fix: Re-Add query mutual rooms advertisement

sender_workers scaling. this time, with feeling!

.pre-commit-config.yaml

@@ -51,7 +51,7 @@ repos:
     hooks:
       - id: cargo-clippy
         name: cargo clippy
-        entry: cargo clippy -- -D warnings
+        entry: cargo clippy --
         language: system
         pass_filenames: false
         types: [rust]

Cargo.lock

@@ -1088,6 +1088,7 @@ dependencies = [
  "serde",
  "serde-saphyr",
  "serde_json",
+ "serde_urlencoded",
  "sha2 0.11.0",
  "termimad",
  "tokio",
@@ -1107,18 +1108,29 @@ dependencies = [
  "axum",
  "axum-extra",
  "base64 0.22.1",
+ "conduwuit_api",
  "conduwuit_build_metadata",
  "conduwuit_core",
+ "conduwuit_database",
  "conduwuit_service",
+ "form_urlencoded",
  "futures",
+ "lettre",
  "memory-serve",
  "rand 0.10.1",
+ "recaptcha-verify",
+ "reqwest 0.12.28",
  "ruma",
  "serde",
+ "serde_json",
+ "serde_urlencoded",
  "thiserror",
  "tower-http 0.7.0",
  "tower-sec-fetch",
+ "tower-sessions",
+ "tower-sessions-core",
  "tracing",
+ "url",
  "validator",
 ]
 
@@ -1534,6 +1546,9 @@ name = "deranged"
 version = "0.5.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7cd812cc2bc1d69d4764bd80df88b4317eaef9e773c75226407d9bc0876b211c"
+dependencies = [
+ "serde_core",
+]
 
 [[package]]
 name = "derive_more"
@@ -5616,6 +5631,22 @@ dependencies = [
  "tracing",
 ]
 
+[[package]]
+name = "tower-cookies"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "151b5a3e3c45df17466454bb74e9ecedecc955269bdedbf4d150dfa393b55a36"
+dependencies = [
+ "axum-core",
+ "cookie",
+ "futures-util",
+ "http",
+ "parking_lot",
+ "pin-project-lite",
+ "tower-layer",
+ "tower-service",
+]
+
 [[package]]
 name = "tower-http"
 version = "0.6.11"
@@ -5687,6 +5718,44 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "8df9b6e13f2d32c91b9bd719c00d1958837bc7dec474d94952798cc8e69eeec3"
 
+[[package]]
+name = "tower-sessions"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "518dca34b74a17cadfcee06e616a09d2bd0c3984eff1769e1e76d58df978fc78"
+dependencies = [
+ "async-trait",
+ "http",
+ "time",
+ "tokio",
+ "tower-cookies",
+ "tower-layer",
+ "tower-service",
+ "tower-sessions-core",
+ "tracing",
+]
+
+[[package]]
+name = "tower-sessions-core"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "568531ec3dfcf3ffe493de1958ae5662a0284ac5d767476ecdb6a34ff8c6b06c"
+dependencies = [
+ "async-trait",
+ "axum-core",
+ "base64 0.22.1",
+ "futures",
+ "http",
+ "parking_lot",
+ "rand 0.9.4",
+ "serde",
+ "serde_json",
+ "thiserror",
+ "time",
+ "tokio",
+ "tracing",
+]
+
 [[package]]
 name = "tracing"
 version = "0.1.44"

Cargo.toml

@@ -559,6 +559,9 @@ features = ["std"]
 [workspace.dependencies.nonzero_ext]
 version = "0.3.0"
 
+[workspace.dependencies.serde_urlencoded]
+version = "0.7.1"
+
 #
 # Patches
 #

changelog.d/+7865cde6.feature.md

@@ -0,0 +1 @@
+Users may now be forbidden from deactivating their own accounts with the new `allow_deactivation` config option. Contributed by @ginger.

changelog.d/+98691708.feature.md

@@ -0,0 +1 @@
+Added support for authenticating clients using the new OAuth 2.0 login API. Contributed by @ginger.

changelog.d/1818.feature.md

@@ -0,0 +1,2 @@
+Improved the performance and reliability of fetching missing events, improving network partition recovery. Contributed
+by @nex.

conduwuit-example.toml

@@ -297,7 +297,7 @@
 
 # This item is undocumented. Please contribute documentation for it.
 #
-#max_fetch_prev_events = 192
+#max_fetch_prev_events = 1024
 
 # How many incoming federation transactions the server is willing to be
 # processing at any given time before it becomes overloaded and starts
@@ -521,17 +521,15 @@
 #
 #recaptcha_private_site_key =
 
-# Policy documents, such as terms and conditions or a privacy policy,
-# which users must agree to when registering an account.
+# Controls whether users are allowed to deactivate their own accounts
+# through the account management panel or their Matrix clients. Server
+# admins can always deactivate users using the relevant admin commands.
 #
-# Example:
-# ```ignore
-# [global.registration_terms.privacy_policy]
-# en = { name = "Privacy Policy", url = "https://homeserver.example/en/privacy_policy.html" }
-# es = { name = "Política de Privacidad", url = "https://homeserver.example/es/privacy_policy.html" }
-# ```
+# Note that, in some jurisdictions, you may be legally required to honor
+# users who request to deactivate their accounts if you set this option
+# to `false`.
 #
-#registration_terms = {}
+#allow_deactivation = true
 
 # Controls whether encrypted rooms and events are allowed.
 #
@@ -645,6 +643,14 @@
 #
 #default_room_acl_deny =
 
+# The number of forward extremities to tolerate in a room before
+# attempting to manually squash them with a "dummy event". Setting this
+# above 20 will hinder its efficacy, and setting it below 5 will cause
+# more dummy events to be sent than necessary (which increases federation
+# traffic).
+#
+#dummy_event_threshold = 10
+
 # Enable OpenTelemetry OTLP tracing export. This replaces the deprecated
 # Jaeger exporter. Traces will be sent via OTLP to a collector (such as
 # Jaeger) that supports the OpenTelemetry Protocol.
@@ -1795,11 +1801,9 @@
 #stream_amplification = 1024
 
 # Number of sender task workers; determines sender parallelism. Default is
-# '0' which means the value is determined internally, likely matching the
-# number of tokio worker-threads or number of cores, etc. Override by
-# setting a non-zero value.
+# core count. Override by setting a different value.
 #
-#sender_workers = 0
+#sender_workers = core count
 
 # Enables listener sockets; can be set to false to disable listening. This
 # option is intended for developer/diagnostic purposes only.
@@ -1987,3 +1991,33 @@
 # `require_email_for_registration`.
 #
 #require_email_for_token_registration = false
+
+#[global.registration_terms]
+
+# The language code to provide to clients along with the policy documents.
+#
+#language = "en"
+
+# Policy documents, such as terms and conditions or a privacy policy,
+# which users must agree to when registering an account.
+#
+# Example:
+# ```ignore
+# [global.registration_terms.documents]
+# privacy_policy = { name = "Privacy Policy", url = "https://homeserver.example/en/privacy_policy.html" }
+# ```
+#
+#documents =
+
+#[global.oauth]
+
+# The compatibility mode to use for OAuth.
+#
+# - "disabled": OAuth will be unavailable. Users will only be able to log
+#   in using legacy authentication.
+# - "hybrid": OAuth and legacy authentication will both be available. Some
+#   clients may only use one or the other.
+# - "exclusive": Only OAuth will be available. Clients which require
+#   legacy authentication will be unable to log in.
+#
+#compatibility_mode = "hybrid"

src/admin/admin.rs

@@ -16,7 +16,7 @@
 };
 
 #[derive(Debug, Parser)]
-#[command(name = conduwuit_core::name(), version = conduwuit_core::version())]
+#[command(name = conduwuit_core::BRANDING, version = conduwuit_core::version())]
 pub enum AdminCommand {
 	#[command(subcommand)]
 	/// Commands for managing appservices

src/admin/debug/commands.rs

@@ -31,7 +31,7 @@
 };
 use tracing_subscriber::EnvFilter;
 
-use crate::admin_command;
+use crate::{PAGE_SIZE, admin_command};
 
 #[admin_command]
 pub(super) async fn echo(&self, message: Vec<String>) -> Result {
@@ -1176,3 +1176,53 @@ pub(super) async fn send_test_email(&self) -> Result {
 
 	Ok(())
 }
+
+#[admin_command]
+pub(super) async fn rooms_by_extremity_count(&self, page: Option<usize>) -> Result {
+	let page = page.unwrap_or(1);
+	// My Giant Chain:tm:
+	let mapped: HashMap<OwnedRoomId, u64> = self
+		.services
+		.rooms
+		.state
+		.all_forward_extremities()
+		.ready_fold(HashMap::new(), move |mut map, (room_id, _)| {
+			let count: u64 = map.get(&room_id).copied().unwrap_or(0);
+			map.insert(room_id, count.saturating_add(1));
+			map
+		})
+		.await
+		.into_iter()
+		.filter_map(|(room_id, count)| (count >= 2).then_some((room_id, count)))
+		.collect();
+	if mapped.is_empty() {
+		return Err!("No more rooms.");
+	}
+
+	let mut rooms = mapped.keys().collect::<Vec<_>>();
+	rooms.sort_by_key(|room_id| {
+		mapped
+			.get(*room_id)
+			.copied()
+			.expect("keys must have values")
+	});
+	rooms.reverse();
+
+	let body = rooms
+		.into_iter()
+		.stream()
+		.skip(page.saturating_sub(1).saturating_mul(PAGE_SIZE))
+		.take(PAGE_SIZE)
+		.map(|room_id| {
+			format!("{room_id}: {}", mapped.get(room_id).copied().expect("keys must have values"))
+		})
+		.collect::<Vec<_>>()
+		.await;
+
+	self.write_str(&format!(
+		"Rooms by extremity count ({}):\n```\n{}\n```",
+		body.len(),
+		body.join("\n")
+	))
+	.await
+}

src/admin/debug/mod.rs

@@ -245,6 +245,11 @@ pub enum DebugCommand {
 	/// Send a test email to the invoking admin's email address
 	SendTestEmail,
 
+	/// Lists room IDs by forward extremity count in descending order
+	RoomsByExtremityCount {
+		page: Option<usize>,
+	},
+
 	/// Developer test stubs
 	#[command(subcommand)]
 	#[allow(non_snake_case)]

src/admin/token/commands.rs

@@ -30,14 +30,37 @@ pub(super) async fn issue_token(&self, expires: super::TokenExpires) -> Result {
 		.issue_token(self.sender_or_service_user().into(), expires);
 
 	self.write_str(&format!(
-		"New registration token issued: `{token}`. {}.",
+		"New registration token issued: `{token}` . {}.",
 		if let Some(expires) = info.expires {
 			format!("{expires}")
 		} else {
 			"Never expires".to_owned()
 		}
 	))
-	.await
+	.await?;
+
+	if self
+		.services
+		.config
+		.oauth
+		.compatibility_mode
+		.oauth_available()
+	{
+		self.write_str(&format!(
+			"\nInvite link using this token: {}",
+			self.services
+				.config
+				.get_client_domain()
+				.join(&format!(
+					"{}/account/register/?flow=trusted&token={token}",
+					conduwuit::ROUTE_PREFIX
+				))
+				.unwrap()
+		))
+		.await?;
+	}
+
+	Ok(())
 }
 
 #[admin_command]

src/admin/user/commands.rs

@@ -1,13 +1,10 @@
-use std::{
-	collections::{BTreeMap, HashSet},
-	fmt::Write as _,
-};
+use std::collections::{BTreeMap, HashSet};
 
 use api::client::{
 	full_user_deactivate, leave_room, recreate_push_rules_and_return, remote_leave_room,
 };
 use conduwuit::{
-	Err, Result, debug_warn, error, info,
+	Err, Result, debug_warn, info,
 	matrix::{Event, pdu::PartialPdu},
 	utils::{self, ReadyExt},
 	warn,
@@ -53,130 +50,22 @@ pub(super) async fn list_users(&self) -> Result {
 #[admin_command]
 pub(super) async fn create_user(&self, username: String, password: Option<String>) -> Result {
 	// Validate user id
-	let user_id = parse_local_user_id(self.services, &username)?;
-
-	if let Err(e) = user_id.validate_strict() {
-		if self.services.config.emergency_password.is_none() {
-			return Err!("Username {user_id} contains disallowed characters or spaces: {e}");
-		}
-	}
-
-	if self.services.users.exists(&user_id).await {
-		return Err!("User {user_id} already exists");
-	}
-
-	let password = password.unwrap_or_else(|| utils::random_string(AUTO_GEN_PASSWORD_LENGTH));
-
-	// Create user
-	self.services
-		.users
-		.create(&user_id, Some(HashedPassword::new(&password)?))
-		.await?;
-
-	// Default to pretty displayname
-	let mut displayname = user_id.localpart().to_owned();
-
-	// If `new_user_displayname_suffix` is set, registration will push whatever
-	// content is set to the user's display name with a space before it
-	if !self
+	let user_id = self
 		.services
-		.server
-		.config
-		.new_user_displayname_suffix
-		.is_empty()
-	{
-		write!(displayname, " {}", self.services.server.config.new_user_displayname_suffix)?;
-	}
+		.users
+		.determine_registration_user_id(Some(username), None, None)
+		.await?;
+
+	let password = HashedPassword::new(
+		&password.unwrap_or_else(|| utils::random_string(AUTO_GEN_PASSWORD_LENGTH)),
+	)?;
 
 	self.services
 		.users
-		.set_displayname(&user_id, Some(displayname));
+		.create_local_account(&user_id, password, None)
+		.await;
 
-	// Initial account data
-	self.services
-		.account_data
-		.update(
-			None,
-			&user_id,
-			ruma::events::GlobalAccountDataEventType::PushRules
-				.to_string()
-				.into(),
-			&serde_json::to_value(ruma::events::push_rules::PushRulesEvent::new(
-				ruma::events::push_rules::PushRulesEventContent::new(
-					ruma::push::Ruleset::server_default(&user_id),
-				),
-			))
-			.unwrap(),
-		)
-		.await?;
-
-	if !self.services.server.config.auto_join_rooms.is_empty() {
-		for room in &self.services.server.config.auto_join_rooms {
-			let Ok(room_id) = self.services.rooms.alias.resolve(room).await else {
-				error!(
-					%user_id,
-					"Failed to resolve room alias to room ID when attempting to auto join {room}, skipping"
-				);
-				continue;
-			};
-
-			if !self
-				.services
-				.rooms
-				.state_cache
-				.server_in_room(self.services.globals.server_name(), &room_id)
-				.await
-			{
-				warn!(
-					"Skipping room {room} to automatically join as we have never joined before."
-				);
-				continue;
-			}
-
-			if let Some(room_server_name) = room.server_name() {
-				match self
-					.services
-					.rooms
-					.membership
-					.join_room(
-						&user_id,
-						&room_id,
-						Some("Automatically joining this room upon registration".to_owned()),
-						&[
-							self.services.globals.server_name().to_owned(),
-							room_server_name.to_owned(),
-						],
-					)
-					.await
-				{
-					| Ok(_response) => {
-						info!("Automatically joined room {room} for user {user_id}");
-					},
-					| Err(e) => {
-						// don't return this error so we don't fail registrations
-						error!(
-							"Failed to automatically join room {room} for user {user_id}: {e}"
-						);
-						self.services
-							.admin
-							.send_text(&format!(
-								"Failed to automatically join room {room} for user {user_id}: \
-								 {e}"
-							))
-							.await;
-					},
-				}
-			}
-		}
-	}
-
-	// we dont add a device since we're not the user, just the creator
-
-	// Make the first user to register an administrator and disable first-run mode.
-	self.services.firstrun.empower_first_user(&user_id).await?;
-
-	self.write_str(&format!("Created user with user_id: {user_id} and password: `{password}`"))
-		.await
+	self.write_str(&format!("Created user {user_id}")).await
 }
 
 #[admin_command]
@@ -302,31 +191,6 @@ pub(super) async fn reset_password(
 	Ok(())
 }
 
-#[admin_command]
-pub(super) async fn issue_password_reset_link(&self, username: String) -> Result {
-	use conduwuit_service::password_reset::{PASSWORD_RESET_PATH, RESET_TOKEN_QUERY_PARAM};
-
-	self.bail_restricted()?;
-
-	let mut reset_url = self
-		.services
-		.config
-		.get_client_domain()
-		.join(PASSWORD_RESET_PATH)
-		.unwrap();
-
-	let user_id = parse_local_user_id(self.services, &username)?;
-	let token = self.services.password_reset.issue_token(user_id).await?;
-	reset_url
-		.query_pairs_mut()
-		.append_pair(RESET_TOKEN_QUERY_PARAM, &token.token);
-
-	self.write_str(&format!("Password reset link issued for {username}: {reset_url}"))
-		.await?;
-
-	Ok(())
-}
-
 #[admin_command]
 pub(super) async fn deactivate_all(&self, no_leave_rooms: bool, force: bool) -> Result {
 	if self.body.len() < 2

src/admin/user/mod.rs

@@ -29,12 +29,6 @@ pub enum UserCommand {
 		password: Option<String>,
 	},
 
-	/// Issue a self-service password reset link for a user.
-	IssuePasswordResetLink {
-		/// Username of the user who may use the link
-		username: String,
-	},
-
 	/// Get a user's associated email address.
 	GetEmail {
 		user_id: String,

src/api/client/account/mod.rs

@@ -24,7 +24,7 @@
 		power_levels::RoomPowerLevelsEventContent,
 	},
 };
-use service::{mailer::messages, uiaa::Identity, users::HashedPassword};
+use service::{mailer::messages, uiaa::UiaaInitiator, users::HashedPassword};
 
 use super::{DEVICE_ID_LENGTH, TOKEN_LENGTH};
 use crate::{Ruma, router::ClientIdentity};
@@ -49,39 +49,16 @@ pub(crate) async fn get_register_available_route(
 	ClientIp(client): ClientIp,
 	body: Ruma<get_username_availability::v3::Request>,
 ) -> Result<get_username_availability::v3::Response> {
-	// Validate user id
-	let user_id =
-		match UserId::parse_with_server_name(&body.username, services.globals.server_name()) {
-			| Ok(user_id) => {
-				if let Err(e) = user_id.validate_strict() {
-					return Err!(Request(InvalidUsername(debug_warn!(
-						"Username {} contains disallowed characters or spaces: {e}",
-						body.username
-					))));
-				}
-
-				user_id
-			},
-			| Err(e) => {
-				return Err!(Request(InvalidUsername(debug_warn!(
-					"Username {} is not valid: {e}",
-					body.username
-				))));
-			},
-		};
-
-	// Check if username is creative enough
-	if services.users.exists(&user_id).await {
-		return Err!(Request(UserInUse("User ID is not available.")));
-	}
-
-	if let Some(ClientIdentity::Appservice { appservice_info, .. }) = &body.identity
-		&& !appservice_info.is_user_match(&user_id)
-	{
-		return Err!(Request(Exclusive("Username is not in an appservice namespace.")));
-	} else if services.appservice.is_exclusive_user_id(&user_id).await {
-		return Err!(Request(Exclusive("Username is reserved by an appservice.")));
-	}
+	let _ = services
+		.users
+		.determine_registration_user_id(
+			Some(body.username.clone()),
+			None,
+			body.identity
+				.as_ref()
+				.and_then(ClientIdentity::appservice_info),
+		)
+		.await?;
 
 	Ok(get_username_availability::v3::Response::new(true))
 }
@@ -109,12 +86,7 @@ pub(crate) async fn change_password_route(
 	ClientIp(client): ClientIp,
 	body: Ruma<change_password::v3::Request>,
 ) -> Result<change_password::v3::Response> {
-	let identity = if let Some(user_id) = body
-		.identity
-		.as_ref()
-		.map(ClientIdentity::expect_sender_user)
-		.transpose()?
-	{
+	let identity = if let Some(identity) = body.identity.as_ref() {
 		// A signed-in user is trying to change their password, prompt them for their
 		// existing one
 
@@ -124,7 +96,10 @@ pub(crate) async fn change_password_route(
 				&body.auth,
 				vec![AuthFlow::new(vec![AuthType::Password])],
 				Box::default(),
-				Some(Identity::from_user_id(user_id)),
+				Some(UiaaInitiator::new(
+					identity.expect_sender_user()?,
+					identity.sender_device(),
+				)),
 			)
 			.await?
 	} else {
@@ -280,16 +255,24 @@ pub(crate) async fn deactivate_route(
 ) -> Result<deactivate::v3::Response> {
 	// Authentication for this endpoint is technically optional,
 	// but we require the user to be logged in
-	let sender_user = body
+	let identity = body
 		.identity
 		.as_ref()
-		.map(ClientIdentity::expect_sender_user)
-		.ok_or_else(|| err!(Request(MissingToken("Missing access token."))))??;
+		.ok_or_else(|| err!(Request(MissingToken("Missing access token."))))?;
+
+	let sender_user = identity.expect_sender_user()?;
+
+	if !services.config.allow_deactivation {
+		return Err!(Request(Unauthorized(
+			"You may not deactivate your own account. Contact your server's administrator for \
+			 assistance."
+		)));
+	}
 
 	// Prompt the user to confirm with their password using UIAA
 	let _ = services
 		.uiaa
-		.authenticate_password(&body.auth, Some(Identity::from_user_id(sender_user)))
+		.authenticate_password(&body.auth, sender_user, identity.sender_device(), None)
 		.await?;
 
 	// Remove profile pictures and display name

src/api/client/account/register.rs

@@ -1,17 +1,15 @@
-use std::{collections::HashMap, fmt::Write};
+use std::collections::HashMap;
 
 use axum::extract::State;
 use axum_client_ip::ClientIp;
 use conduwuit::{
-	Err, Result, debug_info, error, info,
+	Err, Result, debug_info, info,
 	utils::{self},
-	warn,
 };
 use conduwuit_service::Services;
-use futures::{FutureExt, StreamExt};
+use futures::StreamExt;
 use lettre::{Address, message::Mailbox};
 use ruma::{
-	OwnedUserId, UserId,
 	api::client::{
 		account::{
 			register::{self, LoginType, RegistrationKind},
@@ -20,11 +18,6 @@
 		uiaa::{AuthFlow, AuthType},
 	},
 	assign,
-	events::{
-		GlobalAccountDataEventType, push_rules::PushRulesEvent,
-		room::message::RoomMessageEventContent,
-	},
-	push,
 };
 use serde_json::value::RawValue;
 use service::{mailer::messages, users::HashedPassword};
@@ -32,8 +25,6 @@
 use super::{DEVICE_ID_LENGTH, TOKEN_LENGTH};
 use crate::Ruma;
 
-const RANDOM_USER_ID_LENGTH: usize = 10;
-
 /// # `POST /_matrix/client/v3/register`
 ///
 /// Register an account on this homeserver.
@@ -52,8 +43,6 @@ pub(crate) async fn register_route(
 		return Err!(Request(GuestAccessForbidden("Guests may not register on this server.")));
 	}
 
-	let emergency_mode_enabled = services.config.emergency_password.is_some();
-
 	// Allow registration if it's enabled in the config file or if this is the first
 	// run (so the first user account can be created)
 	let allow_registration =
@@ -71,99 +60,59 @@ pub(crate) async fn register_route(
 		)));
 	}
 
-	let identity = if body.identity.is_some() {
-		// Appservices can skip auth
-		None
+	let user_id = if body.body.login_type == Some(LoginType::ApplicationService) {
+		let Some(appservice_info) = &body.identity else {
+			return Err!(Request(Forbidden(
+				"Only appservices can use the appservice login type."
+			)));
+		};
+
+		let user_id = services
+			.users
+			.determine_registration_user_id(body.username.clone(), None, Some(appservice_info))
+			.await?;
+
+		services.users.create(&user_id, None).await?;
+
+		user_id
 	} else {
 		// Perform UIAA to determine the user's identity
 		let (flows, params) = create_registration_uiaa_session(&services).await?;
 
-		Some(
-			services
-				.uiaa
-				.authenticate(&body.auth, flows, params, None)
-				.await?,
-		)
-	};
-
-	// If the user didn't supply a username but did supply an email, use
-	// the email's user as their initial localpart to avoid falling back to
-	// a randomly generated localpart
-	let supplied_username = body.username.clone().or_else(|| {
-		if let Some(identity) = &identity
-			&& let Some(email) = &identity.email
-		{
-			Some(email.user().to_owned())
-		} else {
-			None
-		}
-	});
-
-	let user_id =
-		determine_registration_user_id(&services, supplied_username, emergency_mode_enabled)
+		let identity = services
+			.uiaa
+			.authenticate(&body.auth, flows, params, None)
 			.await?;
 
-	if body.body.login_type == Some(LoginType::ApplicationService) {
-		// For appservice logins, make sure that the user ID is in the appservice's
-		// namespace
+		let password = if let Some(password) = &body.password {
+			HashedPassword::new(password)?
+		} else {
+			return Err!(Request(InvalidParam("A password must be provided.")));
+		};
 
-		match body.identity {
-			| Some(ref info) =>
-				if !info.is_user_match(&user_id) && !emergency_mode_enabled {
-					return Err!(Request(Exclusive(
-						"Username is not in an appservice namespace."
-					)));
-				},
-			| _ => {
-				return Err!(Request(MissingToken("Missing appservice token.")));
-			},
-		}
-	} else if services.appservice.is_exclusive_user_id(&user_id).await && !emergency_mode_enabled
-	{
-		// For non-appservice logins, ban user IDs which are in an appservice's
-		// namespace (unless emergency mode is enabled)
-		return Err!(Request(Exclusive("Username is reserved by an appservice.")));
-	}
+		let user_id = services
+			.users
+			.determine_registration_user_id(body.username.clone(), identity.email.as_ref(), None)
+			.await?;
 
-	let password = if body.identity.is_some() {
-		None
-	} else if let Some(password) = body.password.as_deref() {
-		Some(HashedPassword::new(password)?)
-	} else {
-		return Err!(Request(InvalidParam("A password must be provided")));
+		services
+			.users
+			.create_local_account(&user_id, password, identity.email)
+			.await;
+
+		user_id
 	};
 
-	// Create user
-	services.users.create(&user_id, password).await?;
-
-	// Set an initial display name
-	let mut displayname = user_id.localpart().to_owned();
-
-	// Apply the new user displayname suffix, if it's set
-	if !services.globals.new_user_displayname_suffix().is_empty() && body.identity.is_none() {
-		write!(displayname, " {}", services.server.config.new_user_displayname_suffix)?;
-	}
-
-	services
-		.users
-		.set_displayname(&user_id, Some(displayname.clone()));
-
-	// Initial account data
-	services
-		.account_data
-		.update(
-			None,
-			&user_id,
-			GlobalAccountDataEventType::PushRules.to_string().into(),
-			&serde_json::to_value(PushRulesEvent::new(
-				push::Ruleset::server_default(&user_id).into(),
-			))
-			.expect("should be able to serialize push rules"),
-		)
-		.await?;
-
-	// Generate new device id if the user didn't specify one
 	let (token, device) = if !body.inhibit_login {
+		// If UIAA is disabled, we can't create a device. In that case only appservices
+		// can reach this point in the first place, so we return an error for them.
+		if !services.config.oauth.compatibility_mode.uiaa_available() {
+			return Err!(Request(AppserviceLoginUnsupported(
+				"User-interactive appservice registration is not available on this server."
+			)));
+		}
+
+		// Generate new device id if the user didn't specify one
 		let device_id = body
 			.device_id
 			.clone()
@@ -179,6 +128,7 @@ pub(crate) async fn register_route(
 				&user_id,
 				&device_id,
 				&new_token,
+				None,
 				body.initial_device_display_name.clone(),
 				Some(client.to_string()),
 			)
@@ -189,118 +139,7 @@ pub(crate) async fn register_route(
 		(None, None)
 	};
 
-	debug_info!(%user_id, ?device, "User account was created");
-
-	// If the user registered with an email, associate it with their account.
-	if let Some(identity) = identity
-		&& let Some(email) = identity.email
-	{
-		// This may fail if the email is already in use, but we already check for that
-		// in `/requestToken`, so ignoring the error is acceptable here in the rare case
-		// that an email is sniped by another user between the `/requestToken` request
-		// and the `/register` request.
-		let _ = services
-			.threepid
-			.associate_localpart_email(user_id.localpart(), &email)
-			.await;
-	}
-
-	let device_display_name = body.initial_device_display_name.as_deref().unwrap_or("");
-
-	if body.identity.is_none() {
-		if !device_display_name.is_empty() {
-			let notice = format!(
-				"New user \"{user_id}\" registered on this server from IP {client} and device \
-				 display name \"{device_display_name}\""
-			);
-
-			info!("{notice}");
-			if services.server.config.admin_room_notices {
-				services.admin.notice(&notice).await;
-			}
-		} else {
-			let notice = format!("New user \"{user_id}\" registered on this server.");
-
-			info!("{notice}");
-			if services.server.config.admin_room_notices {
-				services.admin.notice(&notice).await;
-			}
-		}
-	}
-
-	// Make the first user to register an administrator and disable first-run mode.
-	let was_first_user = services.firstrun.empower_first_user(&user_id).await?;
-
-	// If the registering user was not the first and we're suspending users on
-	// register, suspend them.
-	if !was_first_user && services.config.suspend_on_register {
-		// Note that we can still do auto joins for suspended users
-		services
-			.users
-			.suspend_account(&user_id, &services.globals.server_user)
-			.await;
-		// And send an @room notice to the admin room, to prompt admins to review the
-		// new user and ideally unsuspend them if deemed appropriate.
-		if services.server.config.admin_room_notices {
-			services
-				.admin
-				.send_loud_message(RoomMessageEventContent::text_plain(format!(
-					"User {user_id} has been suspended as they are not the first user on this \
-					 server. Please review and unsuspend them if appropriate."
-				)))
-				.await
-				.ok();
-		}
-	}
-
-	if body.identity.is_none() && !services.server.config.auto_join_rooms.is_empty() {
-		for room in &services.server.config.auto_join_rooms {
-			let Ok(room_id) = services.rooms.alias.resolve(room).await else {
-				error!(
-					"Failed to resolve room alias to room ID when attempting to auto join \
-					 {room}, skipping"
-				);
-				continue;
-			};
-
-			if !services
-				.rooms
-				.state_cache
-				.server_in_room(services.globals.server_name(), &room_id)
-				.await
-			{
-				warn!(
-					"Skipping room {room} to automatically join as we have never joined before."
-				);
-				continue;
-			}
-
-			if let Some(room_server_name) = room.server_name() {
-				match services
-					.rooms
-					.membership
-					.join_room(
-						&user_id,
-						&room_id,
-						Some("Automatically joining this room upon registration".to_owned()),
-						&[services.globals.server_name().to_owned(), room_server_name.to_owned()],
-					)
-					.boxed()
-					.await
-				{
-					| Err(e) => {
-						// don't return this error so we don't fail registrations
-						error!(
-							"Failed to automatically join room {room} for user {user_id}: {e}"
-						);
-					},
-					| _ => {
-						info!("Automatically joined room {room} for user {user_id}");
-					},
-				}
-			}
-		}
-	}
+	debug_info!(%user_id, ?device, "New account created via legacy registration");
 
 	Ok(assign!(register::v3::Response::new(user_id), {
 		access_token: token,
@@ -372,21 +211,21 @@ async fn create_registration_uiaa_session(
 
 		// Require all users to agree to the terms and conditions, if configured
 		let terms = &services.config.registration_terms;
-		if !terms.is_empty() {
-			let mut terms =
-				serde_json::to_value(terms.clone()).expect("failed to serialize terms");
+		if !terms.documents.is_empty() {
+			let mut terms_map = HashMap::new();
 
-			// Insert a dummy `version` field
-			for (_, documents) in terms.as_object_mut().unwrap() {
-				let documents = documents.as_object_mut().unwrap();
-
-				documents.insert("version".to_owned(), "latest".into());
+			for (id, document) in &terms.documents {
+				terms_map.insert(id.to_owned(), serde_json::json!({
+					terms.language.clone(): serde_json::to_value(document).expect("should be able to serialize document")
+				}));
 			}
 
+			terms_map.insert("version".to_owned(), "latest".into());
+
 			params.insert(
 				AuthType::Terms.as_str().to_owned(),
 				serde_json::json!({
-					"policies": terms,
+					"policies": terms_map,
 				}),
 			);
 
@@ -419,81 +258,6 @@ async fn create_registration_uiaa_session(
 	Ok((flows, params))
 }
 
-async fn determine_registration_user_id(
-	services: &Services,
-	supplied_username: Option<String>,
-	emergency_mode_enabled: bool,
-) -> Result<OwnedUserId> {
-	if let Some(supplied_username) = supplied_username {
-		// The user gets to pick their username. Do some validation to make sure it's
-		// acceptable.
-
-		// Don't allow registration with forbidden usernames.
-		if services
-			.globals
-			.forbidden_usernames()
-			.is_match(&supplied_username)
-			&& !emergency_mode_enabled
-		{
-			return Err!(Request(Forbidden("Username is forbidden")));
-		}
-
-		// Create and validate the user ID
-		let user_id = match UserId::parse_with_server_name(
-			&supplied_username,
-			services.globals.server_name(),
-		) {
-			| Ok(user_id) => {
-				if let Err(e) = user_id.validate_strict() {
-					// Unless we are in emergency mode, we should follow synapse's behaviour on
-					// not allowing things like spaces and UTF-8 characters in usernames
-					if !emergency_mode_enabled {
-						return Err!(Request(InvalidUsername(debug_warn!(
-							"Username {supplied_username} contains disallowed characters or \
-							 spaces: {e}"
-						))));
-					}
-				}
-
-				// Don't allow registration with user IDs that aren't local
-				if !services.globals.user_is_local(&user_id) {
-					return Err!(Request(InvalidUsername(
-						"Username {supplied_username} is not local to this server"
-					)));
-				}
-
-				user_id
-			},
-			| Err(e) => {
-				return Err!(Request(InvalidUsername(debug_warn!(
-					"Username {supplied_username} is not valid: {e}"
-				))));
-			},
-		};
-
-		if services.users.exists(&user_id).await {
-			return Err!(Request(UserInUse("User ID is not available.")));
-		}
-
-		Ok(user_id)
-	} else {
-		// The user didn't specify a username. Generate a username for
-		// them.
-
-		loop {
-			let user_id = UserId::parse_with_server_name(
-				utils::random_string(RANDOM_USER_ID_LENGTH).to_lowercase(),
-				services.globals.server_name(),
-			)
-			.unwrap();
-
-			if !services.users.exists(&user_id).await {
-				break Ok(user_id);
-			}
-		}
-	}
-}
-
 /// # `POST /_matrix/client/v3/register/email/requestToken`
 ///
 /// Requests a validation email for the purpose of registering a new account.

src/api/client/account/threepid.rs

@@ -11,7 +11,7 @@
 	},
 	thirdparty::{Medium, ThirdPartyIdentifierInit},
 };
-use service::{mailer::messages, uiaa::Identity};
+use service::mailer::messages;
 
 use crate::{Ruma, router::ClientIdentity};
 
@@ -124,15 +124,18 @@ pub(crate) async fn add_3pid_route(
 		.uiaa
 		.authenticate_password(
 			&body.auth,
-			Some(Identity::from_user_id(body.identity.expect_sender_user()?)),
+			body.identity.expect_sender_user()?,
+			body.identity.sender_device(),
+			None,
 		)
 		.await?;
 
 	let email = services
 		.threepid
-		.consume_valid_session(&body.sid, &body.client_secret)
+		.get_valid_session(&body.sid, &body.client_secret)
 		.await
-		.map_err(|message| err!(Request(ThreepidAuthFailed("{message}"))))?;
+		.map_err(|message| err!(Request(ThreepidAuthFailed("{message}"))))?
+		.consume();
 
 	services
 		.threepid

src/api/client/admin/lock.rs

@@ -0,0 +1,90 @@
+use axum::extract::State;
+use conduwuit::{Err, Result};
+use futures::future::{join, join3};
+use ruma::api::client::admin::{is_user_locked, lock_user};
+
+use crate::Ruma;
+
+/// # `GET /_matrix/client/v1/admin/lock/{userId}`
+///
+/// Check the account lock status of a target user
+pub(crate) async fn get_lock_status(
+	State(services): State<crate::State>,
+	body: Ruma<is_user_locked::v1::Request>,
+) -> Result<is_user_locked::v1::Response> {
+	let (admin, active) = join(
+		services.users.is_admin(body.identity.expect_sender_user()?),
+		services.users.is_active(&body.user_id),
+	)
+	.await;
+	if !admin {
+		return Err!(Request(Forbidden("Only server administrators can use this endpoint")));
+	}
+	if !services.globals.user_is_local(&body.user_id) {
+		return Err!(Request(InvalidParam("Can only check the lock status of local users")));
+	}
+	if !active {
+		return Err!(Request(NotFound("Unknown user")));
+	}
+	Ok(is_user_locked::v1::Response::new(
+		services.users.is_locked(&body.user_id).await?,
+	))
+}
+
+/// # `PUT /_matrix/client/v1/admin/lock/{userId}`
+///
+/// Set the account lock status of a target user
+pub(crate) async fn put_lock_status(
+	State(services): State<crate::State>,
+	body: Ruma<lock_user::v1::Request>,
+) -> Result<lock_user::v1::Response> {
+	let sender_user = body.identity.expect_sender_user()?;
+
+	let (sender_admin, active, target_admin) = join3(
+		services.users.is_admin(sender_user),
+		services.users.is_active(&body.user_id),
+		services.users.is_admin(&body.user_id),
+	)
+	.await;
+
+	if !sender_admin {
+		return Err!(Request(Forbidden("Only server administrators can use this endpoint")));
+	}
+	if !services.globals.user_is_local(&body.user_id) {
+		return Err!(Request(InvalidParam("Can only set the lock status of local users")));
+	}
+	if !active {
+		return Err!(Request(NotFound("Unknown user")));
+	}
+	if body.user_id == *sender_user {
+		return Err!(Request(Forbidden("You cannot lock yourself")));
+	}
+	if target_admin {
+		return Err!(Request(Forbidden("You cannot lock another server administrator")));
+	}
+	if services.users.is_locked(&body.user_id).await? == body.locked {
+		// No change
+		return Ok(lock_user::v1::Response::new(body.locked));
+	}
+
+	let action = if body.locked {
+		services
+			.users
+			.suspend_account(&body.user_id, sender_user)
+			.await;
+		"locked"
+	} else {
+		services.users.unsuspend_account(&body.user_id).await;
+		"unlocked"
+	};
+
+	if services.config.admin_room_notices {
+		// Notify the admin room that an account has been un/suspended
+		services
+			.admin
+			.send_text(&format!("{} has been {} by {}.", body.user_id, action, sender_user))
+			.await;
+	}
+
+	Ok(lock_user::v1::Response::new(body.locked))
+}

src/api/client/admin/mod.rs

@@ -1,3 +1,4 @@
+mod lock;
 mod suspend;
 
-pub(crate) use self::suspend::*;
+pub(crate) use self::{lock::*, suspend::*};

src/api/client/admin/suspend.rs

@@ -1,7 +1,7 @@
 use axum::extract::State;
 use conduwuit::{Err, Result};
 use futures::future::{join, join3};
-use ruminuwuity::admin::{get_suspended, set_suspended};
+use ruma::api::client::admin::{is_user_suspended, suspend_user};
 
 use crate::Ruma;
 
@@ -10,8 +10,8 @@
 /// Check the suspension status of a target user
 pub(crate) async fn get_suspended_status(
 	State(services): State<crate::State>,
-	body: Ruma<get_suspended::v1::Request>,
-) -> Result<get_suspended::v1::Response> {
+	body: Ruma<is_user_suspended::v1::Request>,
+) -> Result<is_user_suspended::v1::Response> {
 	let (admin, active) = join(
 		services.users.is_admin(body.identity.expect_sender_user()?),
 		services.users.is_active(&body.user_id),
@@ -26,7 +26,7 @@ pub(crate) async fn get_suspended_status(
 	if !active {
 		return Err!(Request(NotFound("Unknown user")));
 	}
-	Ok(get_suspended::v1::Response::new(
+	Ok(is_user_suspended::v1::Response::new(
 		services.users.is_suspended(&body.user_id).await?,
 	))
 }
@@ -36,8 +36,8 @@ pub(crate) async fn get_suspended_status(
 /// Set the suspension status of a target user
 pub(crate) async fn put_suspended_status(
 	State(services): State<crate::State>,
-	body: Ruma<set_suspended::v1::Request>,
-) -> Result<set_suspended::v1::Response> {
+	body: Ruma<suspend_user::v1::Request>,
+) -> Result<suspend_user::v1::Response> {
 	let sender_user = body.identity.expect_sender_user()?;
 
 	let (sender_admin, active, target_admin) = join3(
@@ -64,7 +64,7 @@ pub(crate) async fn put_suspended_status(
 	}
 	if services.users.is_suspended(&body.user_id).await? == body.suspended {
 		// No change
-		return Ok(set_suspended::v1::Response::new(body.suspended));
+		return Ok(suspend_user::v1::Response::new(body.suspended));
 	}
 
 	let action = if body.suspended {
@@ -86,5 +86,5 @@ pub(crate) async fn put_suspended_status(
 			.await;
 	}
 
-	Ok(set_suspended::v1::Response::new(body.suspended))
+	Ok(suspend_user::v1::Response::new(body.suspended))
 }

src/api/client/capabilities.rs

@@ -12,7 +12,6 @@
 		},
 	},
 };
-use serde_json::json;
 
 use crate::Ruma;
 
@@ -40,21 +39,15 @@ pub(crate) async fn get_capabilities_route(
 	capabilities.get_login_token =
 		GetLoginTokenCapability::new(services.server.config.login_via_existing_session);
 
-	// MSC4133 capability
-	capabilities.set("uk.tcpip.msc4133.profile_fields", json!({"enabled": true}))?;
-
-	capabilities.set(
-		"org.matrix.msc4267.forget_forced_upon_leave",
-		json!({"enabled": services.config.forget_forced_upon_leave}),
-	)?;
+	capabilities.forget_forced_upon_leave.enabled = true;
 
 	if services
 		.users
 		.is_admin(body.identity.expect_sender_user()?)
 		.await
 	{
-		// Advertise suspension API
-		capabilities.set("uk.timedout.msc4323", json!({"suspend": true, "lock": false}))?;
+		capabilities.account_moderation.lock = true;
+		capabilities.account_moderation.suspend = true;
 	}
 
 	Ok(get_capabilities::v3::Response::new(capabilities))

src/api/client/device.rs

@@ -8,7 +8,6 @@
 		self, delete_device, delete_devices, get_device, get_devices, update_device,
 	},
 };
-use service::uiaa::Identity;
 
 use crate::{Ruma, client::DEVICE_ID_LENGTH};
 
@@ -95,6 +94,7 @@ pub(crate) async fn update_device_route(
 					&device_id,
 					&appservice.registration.as_token,
 					None,
+					None,
 					Some(client.to_string()),
 				)
 				.await?;
@@ -119,14 +119,13 @@ pub(crate) async fn delete_device_route(
 	body: Ruma<delete_device::v3::Request>,
 ) -> Result<delete_device::v3::Response> {
 	let sender_user = body.identity.expect_sender_user()?;
-	let appservice = body.identity.appservice_info();
 
 	// Appservices get to skip UIAA for this endpoint
-	if appservice.is_none() {
+	if let Some(sender_device) = body.identity.sender_device() {
 		// Prompt the user to confirm with their password using UIAA
 		let _ = services
 			.uiaa
-			.authenticate_password(&body.auth, Some(Identity::from_user_id(sender_user)))
+			.authenticate_password(&body.auth, sender_user, Some(sender_device), None)
 			.await?;
 	}
 
@@ -155,14 +154,13 @@ pub(crate) async fn delete_devices_route(
 	body: Ruma<delete_devices::v3::Request>,
 ) -> Result<delete_devices::v3::Response> {
 	let sender_user = body.identity.expect_sender_user()?;
-	let appservice = body.identity.appservice_info();
 
 	// Appservices get to skip UIAA for this endpoint
-	if appservice.is_none() {
+	if let Some(sender_device) = body.identity.sender_device() {
 		// Prompt the user to confirm with their password using UIAA
 		let _ = services
 			.uiaa
-			.authenticate_password(&body.auth, Some(Identity::from_user_id(sender_user)))
+			.authenticate_password(&body.auth, sender_user, Some(sender_device), None)
 			.await?;
 	}
 

src/api/client/keys.rs

@@ -26,7 +26,7 @@
 	serde::Raw,
 };
 use serde_json::json;
-use service::uiaa::Identity;
+use service::oauth::OAuthTicket;
 
 use crate::Ruma;
 
@@ -205,7 +205,12 @@ pub(crate) async fn upload_signing_keys_route(
 	{
 		let _ = services
 			.uiaa
-			.authenticate_password(&body.auth, Some(Identity::from_user_id(sender_user)))
+			.authenticate_password(
+				&body.auth,
+				sender_user,
+				body.identity.sender_device(),
+				Some(OAuthTicket::CrossSigningReset),
+			)
 			.await?;
 	}
 

src/api/client/mod.rs

@@ -16,6 +16,7 @@
 pub(super) mod membership;
 pub(super) mod message;
 pub(super) mod mutual_rooms;
+pub(super) mod oauth;
 pub(super) mod openid;
 pub(super) mod presence;
 pub(super) mod profile;
@@ -61,6 +62,7 @@
 pub use membership::{leave_all_rooms, leave_room, remote_leave_room};
 pub(super) use message::*;
 pub(super) use mutual_rooms::*;
+pub(super) use oauth::*;
 pub(super) use openid::*;
 pub(super) use presence::*;
 pub(super) use profile::*;
@@ -73,6 +75,7 @@
 pub(super) use room::*;
 pub(super) use search::*;
 pub(super) use send::*;
+pub use session::handle_login;
 pub(super) use session::*;
 pub(super) use space::*;
 pub(super) use state::*;

src/api/client/oauth/mod.rs

@@ -0,0 +1,56 @@
+use axum::{
+	Json, Router,
+	extract::{Request, State},
+	middleware::{self, Next},
+	response::{IntoResponse, Response},
+	routing::method_routing::{get, post},
+};
+use const_str::concat;
+use http::StatusCode;
+use serde_json::json;
+pub(crate) use server_metadata::*;
+
+mod register_client;
+mod server_metadata;
+mod token;
+
+const BASE_PATH: &str = concat!(conduwuit_core::ROUTE_PREFIX, "/oauth2/");
+const AUTH_CODE_PATH: &str = "grant/authorization_code";
+const JWKS_URI_PATH: &str = "client/keys.json";
+const CLIENT_REGISTER_PATH: &str = "client/register";
+const TOKEN_REVOKE_PATH: &str = "client/revoke";
+const TOKEN_PATH: &str = "grant/token";
+const ACCOUNT_MANAGEMENT_PATH: &str = concat!(conduwuit_core::ROUTE_PREFIX, "/account/deeplink");
+
+pub(crate) fn router(state: crate::State) -> Router<crate::State> {
+	Router::new()
+		.nest(BASE_PATH, oauth_router())
+		.route(
+			"/.well-known/openid-configuration",
+			get(
+				// TODO(unspecced): used by old versions of the matrix-js-sdk
+				async |State(services): State<crate::State>| {
+					Json(authorization_server_metadata(&services).await)
+				},
+			),
+		)
+		.layer(middleware::from_fn_with_state(
+			state,
+			async |State(state): State<crate::State>, request: Request, next: Next| -> Response {
+				if state.config.oauth.compatibility_mode.oauth_available() {
+					next.run(request).await
+				} else {
+					(StatusCode::NOT_FOUND, "OAuth is unavailable on this server").into_response()
+				}
+			},
+		))
+}
+
+fn oauth_router() -> Router<crate::State> {
+	Router::new()
+		.route(concat!("/", CLIENT_REGISTER_PATH), post(register_client::register_client_route))
+		// TODO(unspecced): used by old versions of the matrix-js-sdk
+		.route(concat!("/", JWKS_URI_PATH), get(async || Json(json!({"keys": []}))))
+		.route(concat!("/", TOKEN_PATH), post(token::token_route))
+		.route(concat!("/", TOKEN_REVOKE_PATH), post(token::revoke_token_route))
+}

src/api/client/oauth/register_client.rs

@@ -0,0 +1,28 @@
+use axum::{
+	Json,
+	extract::State,
+	response::{IntoResponse, Response},
+};
+use http::StatusCode;
+use serde::Serialize;
+use service::oauth::client_metadata::ClientMetadata;
+
+#[derive(Serialize)]
+struct RegisteredClient {
+	client_id: String,
+	#[serde(flatten)]
+	metadata: ClientMetadata,
+}
+
+pub(crate) async fn register_client_route(
+	State(services): State<crate::State>,
+	Json(metadata): Json<ClientMetadata>,
+) -> Result<Response, Response> {
+	let client_id = services
+		.oauth
+		.register_client(&metadata)
+		.await
+		.map_err(|err| (StatusCode::BAD_REQUEST, Json(err)).into_response())?;
+
+	Ok(Json(RegisteredClient { client_id, metadata }).into_response())
+}

src/api/client/oauth/server_metadata.rs

@@ -0,0 +1,62 @@
+use axum::extract::State;
+use conduwuit::{Err, Result};
+use ruma::{
+	api::client::discovery::get_authorization_server_metadata::{
+		self, v1::AccountManagementAction,
+	},
+	serde::Raw,
+};
+use serde_json::{Value, json};
+use service::Services;
+
+use crate::{
+	Ruma,
+	client::oauth::{
+		ACCOUNT_MANAGEMENT_PATH, AUTH_CODE_PATH, CLIENT_REGISTER_PATH, JWKS_URI_PATH, TOKEN_PATH,
+		TOKEN_REVOKE_PATH,
+	},
+};
+
+pub(crate) async fn get_authorization_server_metadata_route(
+	State(services): State<crate::State>,
+	_body: Ruma<get_authorization_server_metadata::v1::Request>,
+) -> Result<get_authorization_server_metadata::v1::Response> {
+	if !services.config.oauth.compatibility_mode.oauth_available() {
+		return Err!(Request(Unrecognized("OAuth is unavailable on this server")));
+	}
+
+	let metadata = Raw::new(&authorization_server_metadata(&services).await).unwrap();
+
+	Ok(get_authorization_server_metadata::v1::Response::new(metadata.cast_unchecked()))
+}
+
+pub(crate) async fn authorization_server_metadata(services: &Services) -> Value {
+	let endpoint_base = services
+		.config
+		.get_client_domain()
+		.join(super::BASE_PATH)
+		.unwrap();
+
+	json!({
+		"account_management_uri": endpoint_base.join(ACCOUNT_MANAGEMENT_PATH).unwrap(),
+		"account_management_actions_supported": [
+			AccountManagementAction::AccountDeactivate,
+			AccountManagementAction::CrossSigningReset,
+			AccountManagementAction::DeviceDelete,
+			AccountManagementAction::DeviceView,
+			AccountManagementAction::DevicesList,
+			AccountManagementAction::Profile,
+		],
+		"authorization_endpoint": endpoint_base.join(AUTH_CODE_PATH).unwrap(),
+		"code_challenge_methods_supported": ["S256"],
+		"grant_types_supported": ["authorization_code", "refresh_token"],
+		"issuer": services.config.get_client_domain(),
+		"jwks_uri": endpoint_base.join(JWKS_URI_PATH).unwrap(),
+		"prompt_values_supported": ["create"],
+		"registration_endpoint": endpoint_base.join(CLIENT_REGISTER_PATH).unwrap(),
+		"response_modes_supported": ["query", "fragment"],
+		"response_types_supported": ["code"],
+		"revocation_endpoint": endpoint_base.join(TOKEN_REVOKE_PATH).unwrap(),
+		"token_endpoint": endpoint_base.join(TOKEN_PATH).unwrap(),
+	})
+}

src/api/client/oauth/token.rs

@@ -0,0 +1,23 @@
+use axum::{Form, Json, extract::State, response::IntoResponse};
+use http::StatusCode;
+use service::oauth::grant::{RevokeTokenRequest, TokenRequest};
+
+pub(crate) async fn token_route(
+	State(services): State<crate::State>,
+	Form(request): Form<TokenRequest>,
+) -> impl IntoResponse {
+	match services.oauth.issue_token(request).await {
+		| Ok(response) => Ok(Json(response)),
+		| Err(err) => Err((StatusCode::BAD_REQUEST, Json(err))),
+	}
+}
+
+pub(crate) async fn revoke_token_route(
+	State(services): State<crate::State>,
+	Form(request): Form<RevokeTokenRequest>,
+) -> impl IntoResponse {
+	match services.oauth.revoke_token(request.token).await {
+		| Ok(()) => Ok(StatusCode::OK),
+		| Err(err) => Err((StatusCode::BAD_REQUEST, Json(err))),
+	}
+}

src/api/client/session.rs

@@ -21,7 +21,7 @@
 			},
 			login::{
 				self,
-				v3::{DiscoveryInfo, HomeserverInfo},
+				v3::{DiscoveryInfo, HomeserverInfo, LoginInfo},
 			},
 			logout, logout_all,
 		},
@@ -29,7 +29,6 @@
 	},
 	assign,
 };
-use service::uiaa::Identity;
 
 use super::{DEVICE_ID_LENGTH, TOKEN_LENGTH};
 use crate::Ruma;
@@ -44,6 +43,12 @@ pub(crate) async fn get_login_types_route(
 	ClientIp(client): ClientIp,
 	_body: Ruma<get_login_types::v3::Request>,
 ) -> Result<get_login_types::v3::Response> {
+	if !services.config.oauth.compatibility_mode.uiaa_available() {
+		return Err!(Request(Unrecognized(
+			"User-interactive authentication is not available on this server."
+		)));
+	}
+
 	Ok(get_login_types::v3::Response::new(vec![
 		get_login_types::v3::LoginType::Password(PasswordLoginType::default()),
 		get_login_types::v3::LoginType::ApplicationService(ApplicationServiceLoginType::default()),
@@ -53,7 +58,7 @@ pub(crate) async fn get_login_types_route(
 	]))
 }
 
-pub(crate) async fn handle_login(
+pub async fn handle_login(
 	services: &Services,
 	identifier: Option<&UserIdentifier>,
 	password: &str,
@@ -87,14 +92,6 @@ pub(crate) async fn handle_login(
 		return Err!(Request(InvalidParam("User ID does not belong to this homeserver")));
 	}
 
-	if services.users.is_deactivated(&user_id).await? {
-		return Err!(Request(UserDeactivated("This account has been deactivated.")));
-	}
-
-	if services.users.is_locked(&user_id).await? {
-		return Err!(Request(UserLocked("This account has been locked.")));
-	}
-
 	if services.users.is_login_disabled(&user_id).await {
 		warn!(%user_id, "user attempted to log in with a login-disabled account");
 		return Err!(Request(Forbidden("This account is not permitted to log in.")));
@@ -123,19 +120,29 @@ pub(crate) async fn login_route(
 	ClientIp(client): ClientIp,
 	body: Ruma<login::v3::Request>,
 ) -> Result<login::v3::Response> {
+	if !services.config.oauth.compatibility_mode.uiaa_available() {
+		return match body.login_info {
+			| LoginInfo::ApplicationService(_) => {
+				Err!(Request(AppserviceLoginUnsupported(
+					"User-interactive appservice login is not available on this server."
+				)))
+			},
+			| _ => {
+				Err!(Request(Unrecognized(
+					"User-interactive authentication is not available on this server."
+				)))
+			},
+		};
+	}
+
 	let emergency_mode_enabled = services.config.emergency_password.is_some();
 
 	// Validate login method
-	// TODO: Other login methods
 	let user_id = match &body.login_info {
 		#[allow(deprecated)]
-		| login::v3::LoginInfo::Password(login::v3::Password {
-			identifier,
-			password,
-			user,
-			..
-		}) => handle_login(&services, identifier.as_ref(), password, user.as_ref()).await?,
-		| login::v3::LoginInfo::Token(login::v3::Token { token, .. }) => {
+		| LoginInfo::Password(login::v3::Password { identifier, password, user, .. }) =>
+			handle_login(&services, identifier.as_ref(), password, user.as_ref()).await?,
+		| LoginInfo::Token(login::v3::Token { token, .. }) => {
 			debug!("Got token login type");
 			if !services.server.config.login_via_existing_session {
 				return Err!(Request(Unknown("Token login is not enabled.")));
@@ -143,7 +150,7 @@ pub(crate) async fn login_route(
 			services.users.find_from_login_token(token).await?
 		},
 		#[allow(deprecated)]
-		| login::v3::LoginInfo::ApplicationService(login::v3::ApplicationService {
+		| LoginInfo::ApplicationService(login::v3::ApplicationService {
 			identifier,
 			user,
 			..
@@ -177,7 +184,6 @@ pub(crate) async fn login_route(
 			user_id
 		},
 		| _ => {
-			debug!("/login json_body: {:?}", &body.json_body);
 			return Err!(Request(Unknown(
 				debug_warn!(?body.login_info, "Invalid or unsupported login type")
 			)));
@@ -207,7 +213,7 @@ pub(crate) async fn login_route(
 	if device_exists {
 		services
 			.users
-			.set_token(&user_id, &device_id, &token)
+			.set_token(&user_id, &device_id, &token, None)
 			.await?;
 	} else {
 		services
@@ -216,6 +222,7 @@ pub(crate) async fn login_route(
 				&user_id,
 				&device_id,
 				&token,
+				None,
 				body.initial_device_display_name.clone(),
 				Some(client.to_string()),
 			)
@@ -254,7 +261,7 @@ pub(crate) async fn login_token_route(
 	ClientIp(client): ClientIp,
 	body: Ruma<get_login_token::v1::Request>,
 ) -> Result<get_login_token::v1::Response> {
-	if !services.server.config.login_via_existing_session {
+	if !services.config.login_via_existing_session {
 		return Err!(Request(Forbidden("Login via an existing session is not enabled")));
 	}
 
@@ -263,7 +270,7 @@ pub(crate) async fn login_token_route(
 	// Prompt the user to confirm with their password using UIAA
 	let _ = services
 		.uiaa
-		.authenticate_password(&body.auth, Some(Identity::from_user_id(sender_user)))
+		.authenticate_password(&body.auth, sender_user, body.identity.sender_device(), None)
 		.await?;
 
 	let login_token = utils::random_string(TOKEN_LENGTH);

src/api/client/sync/v5.rs

@@ -70,7 +70,6 @@ pub(crate) async fn sync_events_v5_route(
 	ClientIp(client_ip): ClientIp,
 	body: Ruma<sync_events::v5::Request>,
 ) -> Result<sync_events::v5::Response> {
-	debug_assert!(DEFAULT_BUMP_TYPES.is_sorted(), "DEFAULT_BUMP_TYPES is not sorted");
 	let sender_user = body.identity.expect_sender_user()?;
 	let sender_device = body.identity.expect_sender_device()?;
 

src/api/client/unversioned.rs

@@ -35,8 +35,8 @@ pub(crate) async fn get_supported_versions_route(
 /// `/_matrix/federation/v1/version`
 pub(crate) async fn conduwuit_server_version() -> Result<impl IntoResponse> {
 	Ok(Json(serde_json::json!({
-		"name": conduwuit::version::name(),
-		"version": conduwuit::version::version(),
+		"name": conduwuit::BRANDING,
+		"version": conduwuit::version(),
 	})))
 }
 

src/api/client/well_known.rs

@@ -3,8 +3,7 @@
 use ruma::{
 	api::client::discovery::{
 		discover_homeserver::{self, HomeserverInfo},
-		discover_policy_server,
-		discover_support::{self, Contact, ContactRole},
+		discover_policy_server, discover_support,
 	},
 	assign,
 };
@@ -67,46 +66,7 @@ pub(crate) async fn well_known_support(
 		.as_ref()
 		.map(ToString::to_string);
 
-	let email_address = services.config.well_known.support_email.clone();
-	let matrix_id = services.config.well_known.support_mxid.clone();
-	let pgp_key = services.config.well_known.support_pgp_key.clone();
-
-	// TODO: support defining multiple contacts in the config
-	let mut contacts: Vec<Contact> = vec![];
-
-	let role = services
-		.config
-		.well_known
-		.support_role
-		.clone()
-		.unwrap_or(ContactRole::Admin);
-
-	// Add configured contact if at least one contact method is specified
-	let configured_contact = match (matrix_id, email_address) {
-		| (Some(matrix_id), email_address) =>
-			Some(assign!(Contact::with_matrix_id(role, matrix_id), { email_address })),
-		| (None, Some(email_address)) => Some(Contact::with_email_address(role, email_address)),
-		| (None, None) => None,
-	};
-
-	if let Some(mut configured_contact) = configured_contact {
-		configured_contact.pgp_key = pgp_key;
-
-		contacts.push(configured_contact);
-	}
-
-	// Try to add admin users as contacts if no contacts are configured
-	if contacts.is_empty() {
-		let admin_users = services.admin.get_admins().await;
-
-		for user_id in &admin_users {
-			if *user_id == services.globals.server_user {
-				continue;
-			}
-
-			contacts.push(Contact::with_matrix_id(ContactRole::Admin, user_id.to_owned()));
-		}
-	}
+	let contacts = services.admin.get_support_contacts().await;
 
 	if contacts.is_empty() && support_page.is_none() {
 		// No admin room, no configured contacts, and no support page

src/api/mod.rs

@@ -1,4 +1,5 @@
 #![type_length_limit = "16384"] //TODO: reduce me
+#![recursion_limit = "256"] // My Giant Async Function
 #![allow(clippy::toplevel_ref_arg)]
 
 extern crate conduwuit_core as conduwuit;

src/api/router.rs

@@ -10,7 +10,7 @@
 	response::{IntoResponse, Redirect},
 	routing::{any, get, post},
 };
-use conduwuit::{Server, err};
+use conduwuit::err;
 pub(super) use conduwuit_service::state::State;
 use http::{Uri, uri};
 
@@ -18,8 +18,8 @@
 pub(super) use self::{args::Args as Ruma, auth::ClientIdentity, response::RumaResponse};
 use crate::{admin, client, server};
 
-pub fn build(router: Router<State>, server: &Server) -> Router<State> {
-	let config = &server.config;
+pub fn build(router: Router<State>, state: State) -> Router<State> {
+	let config = &state.server.config;
 	let mut router = router
         .ruma_route(&client::appservice_ping)
 		.ruma_route(&client::get_supported_versions_route)
@@ -181,11 +181,15 @@ pub fn build(router: Router<State>, server: &Server) -> Router<State> {
 		.ruma_route(&client::get_room_summary)
 		.ruma_route(&client::get_suspended_status)
 		.ruma_route(&client::put_suspended_status)
+		.ruma_route(&client::get_lock_status)
+		.ruma_route(&client::put_lock_status)
 		.ruma_route(&client::well_known_support)
 		.ruma_route(&client::well_known_client)
 		.ruma_route(&client::well_known_policy_server)
 		.ruma_route(&client::get_rtc_transports)
 		.ruma_route(&client::room_initial_sync_route)
+		.ruma_route(&client::get_authorization_server_metadata_route)
+		.merge(client::oauth::router(state))
 		.route("/_conduwuit/server_version", get(client::conduwuit_server_version))
 		.route("/_continuwuity/server_version", get(client::conduwuit_server_version))
 		.ruma_route(&admin::rooms::ban::ban_room)

src/api/router/auth.rs

@@ -1,6 +1,7 @@
 use std::any::{Any, TypeId};
 
-use conduwuit::{Err, Result, err};
+use conduwuit::{Err, Error, Result, err};
+use http::StatusCode;
 use ruma::{
 	DeviceId, OwnedDeviceId, OwnedServerName, OwnedUserId, UserId,
 	api::{
@@ -10,12 +11,15 @@
 			AuthScheme, NoAccessToken, NoAuthentication,
 		},
 		client,
+		error::{ErrorKind, UnknownTokenErrorData},
 		federation::authentication::ServerSignatures,
 	},
+	assign,
 };
 use service::{
 	Services,
 	server_keys::{PubKeyMap, PubKeys},
+	users::AccessTokenStatus,
 };
 
 use crate::{router::args::AuthQueryParams, service::appservice::RegistrationInfo};
@@ -162,10 +166,20 @@ async fn verify<B: AsRef<[u8]> + Sync>(
 		query: AuthQueryParams,
 		route: TypeId,
 	) -> Result<Self::Identity> {
-		if output.is_empty() {
-			return Err!(Request(Unauthorized("Missing access token.")));
-		}
-		if let Ok((sender_user, sender_device)) = services.users.find_from_token(&output).await {
+		if let Some((sender_user, sender_device, status)) =
+			services.users.find_from_token(&output).await
+		{
+			// If the token is expired we return a soft logout
+			if matches!(status, AccessTokenStatus::Expired) {
+				return Err(Error::Request(
+					ErrorKind::UnknownToken(
+						assign!(UnknownTokenErrorData::new(), { soft_logout: true }),
+					),
+					"This token has expired".into(),
+					StatusCode::UNAUTHORIZED,
+				));
+			}
+
 			// Locked users can only use /logout and /logout/all
 			if services
 				.users
@@ -176,7 +190,7 @@ async fn verify<B: AsRef<[u8]> + Sync>(
 				if !(route == TypeId::of::<client::session::logout::v3::Request>()
 					|| route == TypeId::of::<client::session::logout_all::v3::Request>())
 				{
-					return Err!(Request(Unauthorized("Your account is locked.")));
+					return Err!(Request(UserLocked("Your account is locked.")));
 				}
 			}
 
@@ -227,7 +241,11 @@ async fn verify<B: AsRef<[u8]> + Sync>(
 				appservice_info: Box::new(appservice_info),
 			})
 		} else {
-			Err!(Request(Unauthorized("Invalid access token.")))
+			Err(Error::Request(
+				ErrorKind::UnknownToken(UnknownTokenErrorData::new()),
+				"Invalid token".into(),
+				StatusCode::UNAUTHORIZED,
+			))
 		}
 	}
 }
@@ -262,9 +280,6 @@ async fn verify<B: AsRef<[u8]> + Sync>(
 		_query: AuthQueryParams,
 		_route: TypeId,
 	) -> Result<Self::Identity> {
-		if output.is_empty() {
-			return Err!(Request(Unauthorized("Missing access token.")));
-		}
 		let Ok(appservice_info) = services.appservice.find_from_token(&output).await else {
 			return Err!(Request(Unauthorized("Invalid appservice token.")));
 		};

src/api/server/get_missing_events.rs

@@ -4,15 +4,11 @@
 use conduwuit::{Err, Event, Result, debug, info, trace, utils::to_canonical_object, warn};
 use ruma::{OwnedEventId, api::federation::event::get_missing_events};
 use serde_json::{json, value::RawValue};
+use service::rooms::event_handler::GET_MISSING_EVENTS_MAX_BATCH_SIZE;
 
 use super::AccessCheck;
 use crate::Ruma;
 
-/// arbitrary number but synapse's is 20 and we can handle lots of these anyways
-const LIMIT_MAX: usize = 50;
-/// spec says default is 10
-const LIMIT_DEFAULT: usize = 10;
-
 /// # `POST /_matrix/federation/v1/get_missing_events/{roomId}`
 ///
 /// Retrieves events that the sender is missing.
@@ -45,8 +41,8 @@ pub(crate) async fn get_missing_events_route(
 	let limit = body
 		.limit
 		.try_into()
-		.unwrap_or(LIMIT_DEFAULT)
-		.min(LIMIT_MAX);
+		.unwrap_or(10)
+		.min(GET_MISSING_EVENTS_MAX_BATCH_SIZE);
 
 	let room_version = services.rooms.state.get_room_version(&body.room_id).await?;
 

src/api/server/send.rs

@@ -7,7 +7,7 @@
 use axum::extract::State;
 use axum_client_ip::ClientIp;
 use conduwuit::{
-	Err, Error, Result, debug, debug_warn, err, error,
+	Err, Error, Result, debug, debug_error, debug_warn, err, error,
 	result::LogErr,
 	state_res::lexicographical_topological_sort,
 	trace,
@@ -133,6 +133,7 @@ async fn wait_for_result(
 }
 
 #[instrument(
+	name="transaction"
 	skip_all,
 	fields(
 		id = ?body.transaction_id.as_str(),
@@ -174,8 +175,14 @@ async fn process_inbound_transaction(
 
 	for (id, result) in &results {
 		if let Err(e) = result {
-			if matches!(e, Error::BadRequest(ErrorKind::NotFound, _)) {
-				debug_warn!("Incoming PDU failed {id}: {e:?}");
+			match e {
+				| Error::BadRequest(
+					ErrorKind::Forbidden | ErrorKind::InvalidParam | ErrorKind::BadJson,
+					..,
+				) => {
+					debug_warn!("Incoming PDU {id} failed: {e:?}");
+				},
+				| _ => debug_error!("Incoming PDU {id} failed: {e:?}"),
 			}
 		}
 	}
@@ -381,6 +388,7 @@ async fn handle_room(
 			.rooms
 			.event_handler
 			.handle_incoming_pdu(origin, room_id, &event_id, value, true)
+			.boxed()
 			.await
 			.map(|_| ());
 		results.push((event_id, result));

src/api/server/version.rs

@@ -11,8 +11,8 @@ pub(crate) async fn get_server_version_route(
 ) -> Result<get_server_version::v1::Response> {
 	Ok(assign!(get_server_version::v1::Response::new(), {
 		server: Some(assign!(get_server_version::v1::Server::new(), {
-			name: Some(conduwuit::version::name().into()),
-			version: Some(conduwuit::version::version().into()),
+			name: Some(conduwuit::BRANDING.into()),
+			version: Some(conduwuit::version().into()),
 		})),
 	}))
 }

src/core/config/mod.rs

@@ -4,7 +4,7 @@
 pub mod proxy;
 
 use std::{
-	collections::{BTreeMap, BTreeSet, HashMap},
+	collections::{BTreeMap, BTreeSet},
 	net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr},
 	path::PathBuf,
 };
@@ -375,7 +375,7 @@ pub struct Config {
 	#[serde(default = "default_max_request_size")]
 	pub max_request_size: usize,
 
-	/// default: 192
+	/// default: 1024
 	#[serde(default = "default_max_fetch_prev_events")]
 	pub max_fetch_prev_events: u16,
 
@@ -655,19 +655,25 @@ pub struct Config {
 	/// even if `recaptcha_site_key` is set.
 	pub recaptcha_private_site_key: Option<String>,
 
-	/// Policy documents, such as terms and conditions or a privacy policy,
-	/// which users must agree to when registering an account.
-	///
-	/// Example:
-	/// ```ignore
-	/// [global.registration_terms.privacy_policy]
-	/// en = { name = "Privacy Policy", url = "https://homeserver.example/en/privacy_policy.html" }
-	/// es = { name = "Política de Privacidad", url = "https://homeserver.example/es/privacy_policy.html" }
-	/// ```
-	///
-	/// default: {}
+	/// display: nested
 	#[serde(default)]
-	pub registration_terms: HashMap<String, HashMap<String, TermsDocument>>,
+	pub registration_terms: RegistrationTerms,
+
+	/// display: nested
+	#[serde(default)]
+	pub oauth: OauthConfig,
+
+	/// Controls whether users are allowed to deactivate their own accounts
+	/// through the account management panel or their Matrix clients. Server
+	/// admins can always deactivate users using the relevant admin commands.
+	///
+	/// Note that, in some jurisdictions, you may be legally required to honor
+	/// users who request to deactivate their accounts if you set this option
+	/// to `false`.
+	///
+	/// default: true
+	#[serde(default = "true_fn")]
+	pub allow_deactivation: bool,
 
 	/// Controls whether encrypted rooms and events are allowed.
 	#[serde(default = "true_fn")]
@@ -781,6 +787,16 @@ pub struct Config {
 	/// a substitute for moderation bots.
 	pub default_room_acl_deny: Option<Vec<String>>,
 
+	/// The number of forward extremities to tolerate in a room before
+	/// attempting to manually squash them with a "dummy event". Setting this
+	/// above 20 will hinder its efficacy, and setting it below 5 will cause
+	/// more dummy events to be sent than necessary (which increases federation
+	/// traffic).
+	///
+	/// default: 10
+	#[serde(default = "default_extremity_threshold")]
+	pub dummy_event_threshold: u8,
+
 	/// display: nested
 	#[serde(default)]
 	pub well_known: WellKnownConfig,
@@ -2071,12 +2087,10 @@ pub struct Config {
 	pub stream_amplification: usize,
 
 	/// Number of sender task workers; determines sender parallelism. Default is
-	/// '0' which means the value is determined internally, likely matching the
-	/// number of tokio worker-threads or number of cores, etc. Override by
-	/// setting a non-zero value.
+	/// core count. Override by setting a different value.
 	///
-	/// default: 0
-	#[serde(default)]
+	/// default: core count
+	#[serde(default = "default_sender_workers")]
 	pub sender_workers: usize,
 
 	/// Enables listener sockets; can be set to false to disable listening. This
@@ -2351,6 +2365,29 @@ pub struct SmtpConfig {
 	pub require_email_for_token_registration: bool,
 }
 
+#[derive(Clone, Debug, Default, Deserialize, Serialize)]
+#[config_example_generator(
+	filename = "conduwuit-example.toml",
+	section = "global.registration_terms",
+	optional = "true"
+)]
+pub struct RegistrationTerms {
+	/// The language code to provide to clients along with the policy documents.
+	///
+	/// default: "en"
+	#[serde(default = "default_terms_language")]
+	pub language: String,
+	/// Policy documents, such as terms and conditions or a privacy policy,
+	/// which users must agree to when registering an account.
+	///
+	/// Example:
+	/// ```ignore
+	/// [global.registration_terms.documents]
+	/// privacy_policy = { name = "Privacy Policy", url = "https://homeserver.example/en/privacy_policy.html" }
+	/// ```
+	pub documents: BTreeMap<String, TermsDocument>,
+}
+
 /// A policy document for use with a m.login.terms stage.
 #[derive(Clone, Debug, Deserialize, Serialize)]
 pub struct TermsDocument {
@@ -2358,6 +2395,43 @@ pub struct TermsDocument {
 	pub url: String,
 }
 
+#[derive(Clone, Debug, Default, Deserialize)]
+#[config_example_generator(
+	filename = "conduwuit-example.toml",
+	section = "global.oauth",
+	optional = "true"
+)]
+pub struct OauthConfig {
+	/// The compatibility mode to use for OAuth.
+	///
+	/// - "disabled": OAuth will be unavailable. Users will only be able to log
+	///   in using legacy authentication.
+	/// - "hybrid": OAuth and legacy authentication will both be available. Some
+	///   clients may only use one or the other.
+	/// - "exclusive": Only OAuth will be available. Clients which require
+	///   legacy authentication will be unable to log in.
+	///
+	/// default: "hybrid"
+	pub compatibility_mode: OAuthMode,
+}
+
+#[derive(Clone, Debug, Default, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum OAuthMode {
+	Disabled,
+	#[default]
+	Hybrid,
+	Exclusive,
+}
+
+impl OAuthMode {
+	#[must_use]
+	pub fn uiaa_available(&self) -> bool { matches!(self, Self::Disabled | Self::Hybrid) }
+
+	#[must_use]
+	pub fn oauth_available(&self) -> bool { matches!(self, Self::Hybrid | Self::Exclusive) }
+}
+
 const DEPRECATED_KEYS: &[&str] = &[
 	"cache_capacity",
 	"conduit_cache_capacity_modifier",
@@ -2455,45 +2529,47 @@ fn default_database_backups_to_keep() -> i16 { 1 }
 
 fn default_db_write_buffer_capacity_mb() -> f64 { 48.0 + parallelism_scaled_f64(4.0) }
 
-fn default_db_cache_capacity_mb() -> f64 { 128.0 + parallelism_scaled_f64(64.0) }
+fn default_db_cache_capacity_mb() -> f64 { 512.0 + parallelism_scaled_f64(512.0) }
 
-fn default_pdu_cache_capacity() -> u32 { parallelism_scaled_u32(10_000).saturating_add(100_000) }
+fn default_pdu_cache_capacity() -> u32 { parallelism_scaled_u32(50_000).saturating_add(100_000) }
 
 fn default_cache_capacity_modifier() -> f64 { 1.0 }
 
 fn default_auth_chain_cache_capacity() -> u32 {
-	parallelism_scaled_u32(10_000).saturating_add(100_000)
-}
-
-fn default_shorteventid_cache_capacity() -> u32 {
 	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
+fn default_shorteventid_cache_capacity() -> u32 {
+	parallelism_scaled_u32(100_000).saturating_add(100_000)
+}
+
 fn default_eventidshort_cache_capacity() -> u32 {
-	parallelism_scaled_u32(25_000).saturating_add(100_000)
+	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
 fn default_eventid_pdu_cache_capacity() -> u32 {
-	parallelism_scaled_u32(25_000).saturating_add(100_000)
+	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
 fn default_shortstatekey_cache_capacity() -> u32 {
-	parallelism_scaled_u32(10_000).saturating_add(100_000)
+	parallelism_scaled_u32(100_000).saturating_add(100_000)
 }
 
 fn default_statekeyshort_cache_capacity() -> u32 {
-	parallelism_scaled_u32(10_000).saturating_add(100_000)
+	parallelism_scaled_u32(50_000).saturating_add(100_000)
 }
 
 fn default_servernameevent_data_cache_capacity() -> u32 {
-	parallelism_scaled_u32(100_000).saturating_add(500_000)
+	parallelism_scaled_u32(100_000).saturating_add(100_000)
 }
 
-fn default_stateinfo_cache_capacity() -> u32 { parallelism_scaled_u32(100) }
+fn default_stateinfo_cache_capacity() -> u32 { parallelism_scaled_u32(500).clamp(100, 12000) }
 
-fn default_roomid_spacehierarchy_cache_capacity() -> u32 { parallelism_scaled_u32(1000) }
+fn default_roomid_spacehierarchy_cache_capacity() -> u32 {
+	parallelism_scaled_u32(500).clamp(100, 12000)
+}
 
-fn default_dns_cache_entries() -> u32 { 32768 }
+fn default_dns_cache_entries() -> u32 { 327_680 }
 
 fn default_dns_min_ttl() -> u64 { 60 * 180 }
 
@@ -2549,7 +2625,7 @@ fn default_pusher_timeout() -> u64 { 60 }
 
 fn default_pusher_idle_timeout() -> u64 { 15 }
 
-fn default_max_fetch_prev_events() -> u16 { 192_u16 }
+fn default_max_fetch_prev_events() -> u16 { 1024 }
 
 fn default_max_concurrent_inbound_transactions() -> usize { 150 }
 
@@ -2652,6 +2728,8 @@ fn default_rocksdb_stats_level() -> u8 { 1 }
 #[inline]
 pub fn default_default_room_version() -> RoomVersionId { RoomVersionId::V12 }
 
+fn default_extremity_threshold() -> u8 { 10 }
+
 fn default_ip_range_denylist() -> Vec<String> {
 	vec![
 		"127.0.0.0/8".to_owned(),
@@ -2701,15 +2779,26 @@ fn default_admin_log_capture() -> String {
 
 fn default_admin_room_tag() -> String { "m.server_notice".to_owned() }
 
+#[must_use]
 #[allow(clippy::as_conversions, clippy::cast_precision_loss)]
-fn parallelism_scaled_f64(val: f64) -> f64 { val * (sys::available_parallelism() as f64) }
+pub fn parallelism_scaled_f64(val: f64) -> f64 { val * (sys::available_parallelism() as f64) }
 
-fn parallelism_scaled_u32(val: u32) -> u32 {
-	let val = val.try_into().expect("failed to cast u32 to usize");
-	parallelism_scaled(val).try_into().unwrap_or(u32::MAX)
+#[must_use]
+#[allow(clippy::as_conversions, clippy::cast_possible_truncation)]
+pub fn parallelism_scaled_u32(val: u32) -> u32 {
+	val.saturating_mul(sys::available_parallelism() as u32)
 }
 
-fn parallelism_scaled(val: usize) -> usize { val.saturating_mul(sys::available_parallelism()) }
+#[must_use]
+#[allow(clippy::as_conversions, clippy::cast_possible_truncation, clippy::cast_possible_wrap)]
+pub fn parallelism_scaled_i32(val: i32) -> i32 {
+	val.saturating_mul(sys::available_parallelism() as i32)
+}
+
+#[must_use]
+pub fn parallelism_scaled(val: usize) -> usize {
+	val.saturating_mul(sys::available_parallelism())
+}
 
 fn default_trusted_server_batch_size() -> usize { 256 }
 
@@ -2729,6 +2818,8 @@ fn default_stream_width_scale() -> f32 { 1.0 }
 
 fn default_stream_amplification() -> usize { 1024 }
 
+fn default_sender_workers() -> usize { parallelism_scaled(1) }
+
 fn default_client_receive_timeout() -> u64 { 75 }
 
 fn default_client_request_timeout() -> u64 { 180 }
@@ -2738,3 +2829,5 @@ fn default_client_response_timeout() -> u64 { 120 }
 fn default_client_shutdown_timeout() -> u64 { 15 }
 
 fn default_sender_shutdown_timeout() -> u64 { 5 }
+
+fn default_terms_language() -> String { "en".to_owned() }

src/core/error/mod.rs

@@ -161,6 +161,7 @@ pub fn message(&self) -> String {
 		match self {
 			| Self::Federation(origin, error) => format!("Answer from {origin}: {error}"),
 			| Self::Ruma(error) => response::ruma_error_message(error),
+			| Self::Request(_, message, _) => message.clone().into_owned(),
 			| _ => format!("{self}"),
 		}
 	}

src/core/error/response.rs

@@ -73,11 +73,8 @@ pub(super) fn bad_request_code(kind: &ErrorKind) -> StatusCode {
 		// 413
 		| TooLarge => StatusCode::PAYLOAD_TOO_LARGE,
 
-		// 405
-		| Unrecognized => StatusCode::METHOD_NOT_ALLOWED,
-
 		// 404
-		| NotFound => StatusCode::NOT_FOUND,
+		| Unrecognized | NotFound => StatusCode::NOT_FOUND,
 
 		// 403
 		| GuestAccessForbidden

src/core/info/version.rs

@@ -7,19 +7,16 @@
 
 use std::sync::OnceLock;
 
-static BRANDING: &str = "continuwuity";
-static WEBSITE: &str = "https://continuwuity.org";
-static SEMANTIC: &str = env!("CARGO_PKG_VERSION");
+pub const BRANDING: &str = "continuwuity";
+pub const ROUTE_PREFIX: &str = "/_continuwuity";
+pub const WEBSITE: &str = "https://continuwuity.org";
+pub const SEMANTIC: &str = env!("CARGO_PKG_VERSION");
 
 static VERSION: OnceLock<String> = OnceLock::new();
 static VERSION_UA: OnceLock<String> = OnceLock::new();
 static USER_AGENT: OnceLock<String> = OnceLock::new();
 static USER_AGENT_MEDIA: OnceLock<String> = OnceLock::new();
 
-#[inline]
-#[must_use]
-pub fn name() -> &'static str { BRANDING }
-
 #[inline]
 pub fn version() -> &'static str { VERSION.get_or_init(init_version) }
 
@@ -32,10 +29,10 @@ pub fn user_agent() -> &'static str { USER_AGENT.get_or_init(init_user_agent) }
 #[inline]
 pub fn user_agent_media() -> &'static str { USER_AGENT_MEDIA.get_or_init(init_user_agent_media) }
 
-fn init_user_agent() -> String { format!("{}/{} (bot; +{WEBSITE})", name(), version_ua()) }
+fn init_user_agent() -> String { format!("{BRANDING}/{} (bot; +{WEBSITE})", version_ua()) }
 
 fn init_user_agent_media() -> String {
-	format!("{}/{} (embedbot; facebookexternalhit/1.1; +{WEBSITE})", name(), version_ua())
+	format!("{BRANDING}/{} (embedbot; facebookexternalhit/1.1; +{WEBSITE})", version_ua())
 }
 
 fn init_version_ua() -> String {

src/core/matrix/pdu/partial.rs

@@ -62,7 +62,7 @@ impl Default for PartialPdu {
 	fn default() -> Self {
 		Self {
 			event_type: "m.room.message".into(),
-			content: Box::<RawJsonValue>::default(),
+			content: to_raw_value("{}").unwrap(),
 			unsigned: None,
 			state_key: None,
 			redacts: None,

src/core/matrix/versions.rs

@@ -22,28 +22,19 @@ pub fn versions() -> Vec<String> {
 		"v1.13".to_owned(),
 		"v1.14".to_owned(),
 		"v1.16".to_owned(),
+		// "v1.17".to_owned(),
+		// v1.17 requires: MSC4326 (AS device masquerading), MSC4312 (m.auth), MSC4190 (AS oauth
+		// user registration).
+		"v1.18".to_owned(),
 	]
 }
 
 #[must_use]
 pub fn unstable_features() -> BTreeMap<String, bool> {
 	BTreeMap::from_iter([
-		("org.matrix.e2e_cross_signing".to_owned(), true),
-		("org.matrix.msc2285.stable".to_owned(), true), /* private read receipts (https://github.com/matrix-org/matrix-spec-proposals/pull/2285) */
 		("uk.half-shot.msc2666.query_mutual_rooms".to_owned(), true), /* query mutual rooms (https://github.com/matrix-org/matrix-spec-proposals/pull/2666) */
-		("org.matrix.msc2836".to_owned(), true), /* threading/threads (https://github.com/matrix-org/matrix-spec-proposals/pull/2836) */
-		("org.matrix.msc2946".to_owned(), true), /* spaces/hierarchy summaries (https://github.com/matrix-org/matrix-spec-proposals/pull/2946) */
-		("org.matrix.msc3026.busy_presence".to_owned(), true), /* busy presence status (https://github.com/matrix-org/matrix-spec-proposals/pull/3026) */
-		("org.matrix.msc3827".to_owned(), true), /* filtering of /publicRooms by room type (https://github.com/matrix-org/matrix-spec-proposals/pull/3827) */
-		("org.matrix.msc3952_intentional_mentions".to_owned(), true), /* intentional mentions (https://github.com/matrix-org/matrix-spec-proposals/pull/3952) */
-		("org.matrix.msc3916.stable".to_owned(), true), /* authenticated media (https://github.com/matrix-org/matrix-spec-proposals/pull/3916) */
-		("org.matrix.msc4180".to_owned(), true), /* stable flag for 3916 (https://github.com/matrix-org/matrix-spec-proposals/pull/4180) */
-		("uk.tcpip.msc4133".to_owned(), true), /* Extending User Profile API with Key:Value Pairs (https://github.com/matrix-org/matrix-spec-proposals/pull/4133) */
-		("us.cloke.msc4175".to_owned(), true), /* Profile field for user time zone (https://github.com/matrix-org/matrix-spec-proposals/pull/4175) */
 		("org.matrix.simplified_msc3575".to_owned(), true), /* Simplified Sliding sync (https://github.com/matrix-org/matrix-spec-proposals/pull/4186) */
-		("uk.timedout.msc4323".to_owned(), true), /* agnostic suspend (https://github.com/matrix-org/matrix-spec-proposals/pull/4323) */
 		("org.matrix.msc4155".to_owned(), true), /* invite filtering (https://github.com/matrix-org/matrix-spec-proposals/pull/4155) */
 		("computer.gingershaped.msc4466".to_owned(), true), /* profile change propagation (https://github.com/matrix-org/matrix-spec-proposals/pull/4466) */
-		("org.matrix.msc4380.stable".to_owned(), true),
 	])
 }

src/core/mod.rs

@@ -34,10 +34,7 @@ macro_rules! mod_dtor {
 pub use conduwuit_build_metadata as build_metadata;
 pub use config::Config;
 pub use error::Error;
-pub use info::{
-	version,
-	version::{name, version},
-};
+pub use info::version::*;
 pub use matrix::{Event, EventTypeExt, Pdu, PduCount, PduEvent, PduId, pdu, state_res};
 pub use parking_lot::{Mutex as SyncMutex, RwLock as SyncRwLock};
 pub use server::Server;

src/core/utils/hash/sha256.rs

@@ -5,6 +5,7 @@
 /// Sha256 hash (input gather joined by 0xFF bytes)
 #[must_use]
 #[tracing::instrument(skip(inputs), level = "trace")]
+#[allow(clippy::unnecessary_fallible_conversions)]
 pub fn delimited<'a, T, I>(mut inputs: I) -> DigestOut
 where
 	I: Iterator<Item = T> + 'a,
@@ -25,6 +26,7 @@ pub fn delimited<'a, T, I>(mut inputs: I) -> DigestOut
 /// Sha256 hash (input gather)
 #[must_use]
 #[tracing::instrument(skip(inputs), level = "trace")]
+#[allow(clippy::unnecessary_fallible_conversions)]
 pub fn concat<'a, T, I>(inputs: I) -> DigestOut
 where
 	I: Iterator<Item = T> + 'a,
@@ -43,6 +45,7 @@ pub fn concat<'a, T, I>(inputs: I) -> DigestOut
 #[inline]
 #[must_use]
 #[tracing::instrument(skip(input), level = "trace")]
+#[allow(clippy::unnecessary_fallible_conversions)]
 pub fn hash<T>(input: T) -> DigestOut
 where
 	T: AsRef<[u8]>,

src/core/utils/time.rs

@@ -61,17 +61,23 @@ pub fn format(ts: SystemTime, str: &str) -> String {
 pub fn pretty(d: Duration) -> String {
 	use Unit::*;
 
-	let fmt = |w, f, u| format!("{w}.{f} {u}");
-	let gen64 = |w, f, u| fmt(w, (f * 100.0) as u32, u);
-	let gen128 = |w, f, u| gen64(u64::try_from(w).expect("u128 to u64"), f, u);
+	let fmt = |w, u| {
+		if w == 1 {
+			format!("{w} {u}")
+		} else {
+			format!("{w} {u}s")
+		}
+	};
+	let gen64 = |w, u| fmt(w, u);
+	let gen128 = |w, u| gen64(u64::try_from(w).expect("u128 to u64"), u);
 	match whole_and_frac(d) {
-		| (Days(whole), frac) => gen64(whole, frac, "days"),
-		| (Hours(whole), frac) => gen64(whole, frac, "hours"),
-		| (Mins(whole), frac) => gen64(whole, frac, "minutes"),
-		| (Secs(whole), frac) => gen64(whole, frac, "seconds"),
-		| (Millis(whole), frac) => gen128(whole, frac, "milliseconds"),
-		| (Micros(whole), frac) => gen128(whole, frac, "microseconds"),
-		| (Nanos(whole), frac) => gen128(whole, frac, "nanoseconds"),
+		| (Days(whole), _) => gen64(whole, "day"),
+		| (Hours(whole), _) => gen64(whole, "hour"),
+		| (Mins(whole), _) => gen64(whole, "minute"),
+		| (Secs(whole), _) => gen64(whole, "second"),
+		| (Millis(whole), _) => gen128(whole, "millisecond"),
+		| (Micros(whole), _) => gen128(whole, "microsecond"),
+		| (Nanos(whole), _) => gen128(whole, "nanosecond"),
 	}
 }
 

src/database/engine/cf_opts.rs

@@ -29,7 +29,7 @@ fn descriptor_cf_options(
 	set_table_options(&mut opts, &desc, cache)?;
 
 	opts.set_min_write_buffer_number(1);
-	opts.set_max_write_buffer_number(2);
+	opts.set_max_write_buffer_number(3);
 	opts.set_write_buffer_size(desc.write_size);
 
 	opts.set_target_file_size_base(desc.file_size);

src/database/maps.rs

@@ -49,6 +49,10 @@ pub(super) fn open_list(db: &Arc<Engine>, maps: &[Descriptor]) -> Result<Maps> {
 		name: "bannedroomids",
 		..descriptor::RANDOM_SMALL
 	},
+	Descriptor {
+		name: "clientid_clientmetadata",
+		..descriptor::RANDOM_SMALL
+	},
 	Descriptor {
 		name: "disabledroomids",
 		..descriptor::RANDOM_SMALL
@@ -157,6 +161,10 @@ pub(super) fn open_list(db: &Arc<Engine>, maps: &[Descriptor]) -> Result<Maps> {
 		name: "referencedevents",
 		..descriptor::RANDOM
 	},
+	Descriptor {
+		name: "refreshtoken_refreshtokeninfo",
+		..descriptor::RANDOM_SMALL
+	},
 	Descriptor {
 		name: "registrationtoken_info",
 		..descriptor::RANDOM_SMALL
@@ -187,6 +195,10 @@ pub(super) fn open_list(db: &Arc<Engine>, maps: &[Descriptor]) -> Result<Maps> {
 		val_size_hint: Some(8),
 		..descriptor::RANDOM_SMALL
 	},
+	Descriptor {
+		name: "roomid_mindepth",
+		..descriptor::RANDOM_SMALL
+	},
 	Descriptor {
 		name: "roomserverids",
 		..descriptor::RANDOM_SMALL
@@ -366,6 +378,14 @@ pub(super) fn open_list(db: &Arc<Engine>, maps: &[Descriptor]) -> Result<Maps> {
 		name: "userdevicetxnid_response",
 		..descriptor::RANDOM_SMALL
 	},
+	Descriptor {
+		name: "userdeviceid_oauthsessioninfo",
+		..descriptor::RANDOM_SMALL
+	},
+	Descriptor {
+		name: "userdeviceid_tokenexpires",
+		..descriptor::RANDOM_SMALL
+	},
 	Descriptor {
 		name: "userfilterid_filter",
 		..descriptor::RANDOM_SMALL
@@ -470,4 +490,8 @@ pub(super) fn open_list(db: &Arc<Engine>, maps: &[Descriptor]) -> Result<Maps> {
 		name: "userroomid_invitesender",
 		..descriptor::RANDOM_SMALL
 	},
+	Descriptor {
+		name: "websessionid_session",
+		..descriptor::RANDOM_SMALL
+	},
 ];

src/main/clap.rs

@@ -15,7 +15,7 @@
 #[clap(
 	about,
 	long_about = None,
-	name = conduwuit_core::name(),
+	name = conduwuit_core::BRANDING,
 	version = conduwuit_core::version(),
 )]
 pub struct Args {

src/main/logging.rs

@@ -110,7 +110,7 @@ pub(crate) fn init(
 				.with_batch_exporter(exporter)
 				.build();
 
-			let tracer = provider.tracer(conduwuit_core::name());
+			let tracer = provider.tracer(conduwuit_core::BRANDING);
 
 			let telemetry = tracing_opentelemetry::layer().with_tracer(tracer);
 

src/main/sentry.rs

@@ -47,7 +47,7 @@ fn options(config: &Config) -> ClientOptions {
 		traces_sample_rate: config.sentry_traces_sample_rate,
 		debug: cfg!(debug_assertions),
 		release: release_name(),
-		user_agent: conduwuit_core::version::user_agent().into(),
+		user_agent: conduwuit_core::user_agent().into(),
 		attach_stacktrace: config.sentry_attach_stacktrace,
 		before_send: Some(Arc::new(before_send)),
 		before_breadcrumb: Some(Arc::new(before_breadcrumb)),

src/router/request.rs

@@ -8,7 +8,7 @@
 	extract::State,
 	response::{IntoResponse, Response},
 };
-use conduwuit::{Result, debug, debug_error, debug_warn, err, error, trace};
+use conduwuit::{Result, debug_warn, err, error, info, trace};
 use conduwuit_service::Services;
 use futures::FutureExt;
 use http::{Method, StatusCode, Uri};
@@ -102,17 +102,19 @@ fn handle_result(method: &Method, uri: &Uri, result: Response) -> Result<Respons
 	let reason = status.canonical_reason().unwrap_or("Unknown Reason");
 
 	if status.is_server_error() {
-		error!(%method, %uri, "{code} {reason}");
+		info!(%method, %uri, "{code} {reason}");
 	} else if status.is_client_error() {
-		debug_error!(%method, %uri, "{code} {reason}");
+		info!(%method, %uri, "{code} {reason}");
 	} else if status.is_redirection() {
-		debug!(%method, %uri, "{code} {reason}");
+		trace!(%method, %uri, "{code} {reason}");
 	} else {
 		trace!(%method, %uri, "{code} {reason}");
 	}
 
 	if status == StatusCode::METHOD_NOT_ALLOWED {
-		return Ok(err!(Request(Unrecognized("Method Not Allowed"))).into_response());
+		return Ok(
+			err!(Request(Unrecognized("Method not allowed"), METHOD_NOT_ALLOWED)).into_response()
+		);
 	}
 
 	Ok(result)

src/router/router.rs

@@ -9,8 +9,8 @@
 pub(crate) fn build(services: &Arc<Services>) -> (Router, Guard) {
 	let router = Router::<state::State>::new();
 	let (state, guard) = state::create(services.clone());
-	let router = conduwuit_api::router::build(router, &services.server)
-		.merge(conduwuit_web::build())
+	let router = conduwuit_api::router::build(router, state)
+		.merge(conduwuit_web::build(services))
 		.fallback(not_found)
 		.with_state(state);
 

src/service/Cargo.toml

@@ -119,6 +119,7 @@ recaptcha-verify = { version = "0.2.0", default-features = false }
 reqwest_recaptcha = { package = "reqwest", version = "0.12.28", default-features = false, features = ["rustls-tls-native-roots-no-provider"]  } # As long as recaptcha-verify's reqwest is outdated
 yansi.workspace = true
 lettre.workspace = true
+serde_urlencoded.workspace = true
 
 [target.'cfg(all(unix, target_os = "linux"))'.dependencies]
 sd-notify.workspace = true

src/service/admin/mod.rs

@@ -18,6 +18,8 @@
 use loole::{Receiver, Sender};
 use ruma::{
 	OwnedEventId, OwnedMxcUri, OwnedRoomId, OwnedUserId, RoomId, UInt, UserId,
+	api::client::discovery::discover_support::{Contact, ContactRole},
+	assign,
 	events::{
 		Mentions,
 		room::message::{
@@ -28,7 +30,7 @@
 use tokio::sync::RwLock;
 
 use crate::{
-	Dep, account_data, globals,
+	Dep, account_data, config, globals,
 	media::{MXC_LENGTH, mxc::Mxc},
 	rooms::{self, state::RoomMutexGuard},
 };
@@ -44,6 +46,7 @@ pub struct Service {
 
 struct Services {
 	server: Arc<Server>,
+	config: Dep<config::Service>,
 	globals: Dep<globals::Service>,
 	alias: Dep<rooms::alias::Service>,
 	timeline: Dep<rooms::timeline::Service>,
@@ -115,6 +118,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 		Ok(Arc::new(Self {
 			services: Services {
 				server: args.server.clone(),
+				config: args.depend::<config::Service>("config"),
 				globals: args.depend::<globals::Service>("globals"),
 				alias: args.depend::<rooms::alias::Service>("rooms::alias"),
 				timeline: args.depend::<rooms::timeline::Service>("rooms::timeline"),
@@ -623,4 +627,52 @@ pub(super) fn set_services(&self, services: Option<&Arc<crate::Services>>) {
 		let weak = services.map(Arc::downgrade);
 		*receiver = weak;
 	}
+
+	/// Get the server's configured support contacts.
+	pub async fn get_support_contacts(&self) -> Vec<Contact> {
+		let email_address = self.services.config.well_known.support_email.clone();
+		let matrix_id = self.services.config.well_known.support_mxid.clone();
+		let pgp_key = self.services.config.well_known.support_pgp_key.clone();
+
+		// TODO: support defining multiple contacts in the config
+		let mut contacts: Vec<Contact> = vec![];
+
+		let role = self
+			.services
+			.config
+			.well_known
+			.support_role
+			.clone()
+			.unwrap_or(ContactRole::Admin);
+
+		// Add configured contact if at least one contact method is specified
+		let configured_contact = match (matrix_id, email_address) {
+			| (Some(matrix_id), email_address) =>
+				Some(assign!(Contact::with_matrix_id(role, matrix_id), { email_address })),
+			| (None, Some(email_address)) =>
+				Some(Contact::with_email_address(role, email_address)),
+			| (None, None) => None,
+		};
+
+		if let Some(mut configured_contact) = configured_contact {
+			configured_contact.pgp_key = pgp_key;
+
+			contacts.push(configured_contact);
+		}
+
+		// Try to add admin users as contacts if no contacts are configured
+		if contacts.is_empty() {
+			let admin_users = self.get_admins().await;
+
+			for user_id in &admin_users {
+				if *user_id == self.services.globals.server_user {
+					continue;
+				}
+
+				contacts.push(Contact::with_matrix_id(ContactRole::Admin, user_id.to_owned()));
+			}
+		}
+
+		contacts
+	}
 }

src/service/appservice/mod.rs

@@ -67,7 +67,7 @@ async fn worker(self: Arc<Self>) -> Result {
 		for (id, registration) in appservices {
 			// During startup, resolve any token collisions in favour of appservices
 			// by logging out conflicting user devices
-			if let Ok((user_id, device_id)) = self
+			if let Some((user_id, device_id, _)) = self
 				.services
 				.users
 				.find_from_token(&registration.as_token)
@@ -158,7 +158,7 @@ pub async fn register_appservice(
 			.users
 			.find_from_token(&registration.as_token)
 			.await
-			.is_ok()
+			.is_some()
 		{
 			return Err(err!(Request(InvalidParam(
 				"Cannot register appservice: The provided token is already in use by a user \

src/service/client/mod.rs

@@ -39,7 +39,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 		let url_preview_user_agent = config
 			.url_preview_user_agent
 			.clone()
-			.unwrap_or_else(|| conduwuit::version::user_agent_media().to_owned());
+			.unwrap_or_else(|| conduwuit::user_agent_media().to_owned());
 
 		Ok(Arc::new(Self {
 			default: base(config)?
@@ -149,7 +149,7 @@ fn base(config: &Config) -> Result<reqwest::ClientBuilder> {
 		.timeout(Duration::from_secs(config.request_total_timeout))
 		.pool_idle_timeout(Duration::from_secs(config.request_idle_timeout))
 		.pool_max_idle_per_host(config.request_idle_per_host.into())
-		.user_agent(conduwuit::version::user_agent())
+		.user_agent(conduwuit::user_agent())
 		.redirect(redirect::Policy::limited(6))
         .danger_accept_invalid_certs(config.allow_invalid_tls_certificates_yes_i_know_what_the_fuck_i_am_doing_with_this_and_i_know_this_is_insecure)
 		.connection_verbose(cfg!(debug_assertions));

src/service/firstrun/mod.rs

@@ -6,7 +6,7 @@
 use askama::Template;
 use async_trait::async_trait;
 use conduwuit::{Result, info, utils::ReadyExt};
-use futures::{FutureExt, StreamExt};
+use futures::StreamExt;
 use ruma::{UserId, events::room::message::RoomMessageEventContent};
 
 use crate::{
@@ -120,7 +120,7 @@ fn disable_first_run(&self) -> bool {
 	///
 	/// Returns Ok(true) if the specified user was the first user, and Ok(false)
 	/// if they were not.
-	pub async fn empower_first_user(&self, user: &UserId) -> Result<bool> {
+	pub async fn empower_first_user(&self, user: &UserId) -> bool {
 		#[derive(Template)]
 		#[template(path = "welcome.md")]
 		struct WelcomeMessage<'a> {
@@ -130,10 +130,14 @@ struct WelcomeMessage<'a> {
 
 		// If first run mode isn't active, do nothing.
 		if !self.disable_first_run() {
-			return Ok(false);
+			return false;
 		}
 
-		self.services.admin.make_user_admin(user).boxed().await?;
+		self.services
+			.admin
+			.make_user_admin(user)
+			.await
+			.expect("should have been able to empower the first user");
 
 		// Send the welcome message
 		let welcome_message = WelcomeMessage {
@@ -146,11 +150,12 @@ struct WelcomeMessage<'a> {
 		self.services
 			.admin
 			.send_loud_message(RoomMessageEventContent::text_markdown(welcome_message))
-			.await?;
+			.await
+			.expect("should have been able to send welcome message");
 
 		info!("{user} has been invited to the admin room as the first user.");
 
-		Ok(true)
+		true
 	}
 
 	/// Get the single-use registration token which may be used to create the
@@ -181,7 +186,7 @@ pub fn print_first_run_banner(&self) {
 		eprintln!(
 			"Welcome to {} {}!",
 			"Continuwuity".bold().bright_magenta(),
-			conduwuit::version::version().bold()
+			conduwuit::version().bold()
 		);
 		eprintln!();
 		eprintln!(

src/service/mailer/mod.rs

@@ -92,8 +92,8 @@ pub async fn send<Template: MessageTemplate>(
 
 		let message = MessageBuilder::new()
 			.from(self.sender.clone())
-			.to(recipient)
-			.subject(subject)
+			.to(recipient.clone())
+			.subject(subject.clone())
 			.date_now()
 			.header(ContentType::TEXT_PLAIN)
 			.body(body)
@@ -104,6 +104,8 @@ pub async fn send<Template: MessageTemplate>(
 			.await
 			.map_err(|err: TransportError| err!("Failed to send message: {err}"))?;
 
+		info!(recipient = recipient.to_string(), ?subject, "Email sent");
+
 		Ok(())
 	}
 }

src/service/mod.rs

@@ -27,7 +27,7 @@
 pub mod mailer;
 pub mod media;
 pub mod moderation;
-pub mod password_reset;
+pub mod oauth;
 pub mod presence;
 pub mod pusher;
 pub mod registration_tokens;

src/service/oauth/client_metadata.rs

@@ -0,0 +1,196 @@
+use std::{collections::BTreeSet, hash::Hash};
+
+use itertools::Itertools;
+use serde::{Deserialize, Deserializer, Serialize};
+use url::Url;
+
+#[derive(Clone, Debug, PartialEq, Eq, Deserialize, Serialize)]
+#[non_exhaustive]
+pub struct ClientMetadata {
+	#[serde(default)]
+	pub application_type: ApplicationType,
+
+	#[serde(default, skip_serializing_if = "Option::is_none")]
+	pub client_name: Option<String>,
+
+	pub client_uri: Url,
+
+	#[serde(default, deserialize_with = "btreeset_skip_err")]
+	pub grant_types: BTreeSet<GrantType>,
+
+	#[serde(default, skip_serializing_if = "Option::is_none")]
+	pub logo_uri: Option<Url>,
+
+	#[serde(default, skip_serializing_if = "Option::is_none")]
+	pub policy_uri: Option<Url>,
+
+	#[serde(default)]
+	pub redirect_uris: Vec<Url>,
+
+	#[serde(default, deserialize_with = "btreeset_skip_err")]
+	pub response_types: BTreeSet<ResponseType>,
+
+	#[serde(default, skip_serializing_if = "Option::is_none")]
+	pub token_endpoint_auth_method: Option<String>,
+
+	#[serde(default, skip_serializing_if = "Option::is_none")]
+	pub tos_uri: Option<Url>,
+}
+
+impl ClientMetadata {
+	pub(super) const ACCEPTABLE_LOCALHOSTS: [&str; 3] = ["localhost", "127.0.0.1", "[::1]"];
+
+	pub(super) fn validate(&self) -> Result<(), &'static str> {
+		let Some(client_domain) = self.client_uri.domain() else {
+			return Err("Client URI must have a domain.");
+		};
+
+		if self.client_uri.scheme() != "https" {
+			return Err("Client URI must be HTTPS.");
+		}
+
+		if !self.client_uri.username().is_empty() || self.client_uri.password().is_some() {
+			return Err("Client URI must not include credentials.");
+		}
+
+		for uri in [&self.logo_uri, &self.policy_uri, &self.tos_uri]
+			.iter()
+			.filter_map(|uri| uri.as_ref())
+		{
+			if uri.scheme() != "https" {
+				return Err("All metadata URIs must be HTTPS.");
+			}
+
+			if !uri.username().is_empty() || uri.password().is_some() {
+				return Err("All metadata URIs must not include credentials.");
+			}
+
+			if !uri
+				.domain()
+				.is_some_and(|domain| is_subdomain(domain, client_domain))
+			{
+				return Err("All metadata URIs must be subdomains of the client URI.");
+			}
+		}
+
+		for uri in &self.redirect_uris {
+			match uri.scheme() {
+				| "https" => {
+					// HTTPS URIs are okay for native and web clients
+
+					if !uri.username().is_empty() || uri.password().is_some() {
+						return Err("HTTPS redirect URIs must not contain credentials.");
+					}
+				},
+				| "http" if self.application_type == ApplicationType::Native => {
+					if uri
+						.host_str()
+						.is_none_or(|host| !Self::ACCEPTABLE_LOCALHOSTS.contains(&host))
+					{
+						return Err("HTTP redirect URIs for native applications must only \
+						            refer to localhost.");
+					}
+
+					if uri.port().is_some() {
+						return Err("HTTP redirect URIs for native applications do not need to \
+						            specify a port. All ports will be accepted during \
+						            authorization.");
+					}
+				},
+				| private_scheme if self.application_type == ApplicationType::Native => {
+					let rdns_client_uri = client_domain.split('.').rev().join(".");
+
+					if !private_scheme.starts_with(&rdns_client_uri) {
+						return Err("Private-use scheme URIs for native applications must \
+						            begin with the application's client URI domain in \
+						            reverse-DNS notation.");
+					}
+
+					if uri.has_authority() {
+						return Err("Private-use scheme URIs for native applications must not \
+						            have an authority.");
+					}
+				},
+				| _ =>
+					return Err("A redirect URI's scheme is not valid for this application type."),
+			}
+		}
+
+		Ok(())
+	}
+}
+
+#[derive(Clone, Debug, Default, PartialEq, Eq, Deserialize, Serialize)]
+#[serde(rename_all = "snake_case")]
+pub enum ApplicationType {
+	#[default]
+	Web,
+	Native,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, Deserialize, Serialize)]
+#[serde(rename_all = "snake_case")]
+pub enum GrantType {
+	AuthorizationCode,
+	RefreshToken,
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, Hash, PartialOrd, Ord, Deserialize, Serialize)]
+#[serde(rename_all = "snake_case")]
+#[non_exhaustive]
+pub enum ResponseType {
+	Code,
+}
+
+/// Deserialize a BTreeSet from a sequence, skipping items which fail to
+/// deserialize. This is used as a deserialize helper for ClientMetadata to
+/// ignore unknown enum variants in a few fields.
+fn btreeset_skip_err<'de, D, V>(de: D) -> Result<BTreeSet<V>, D::Error>
+where
+	D: Deserializer<'de>,
+	V: Deserialize<'de> + Hash + Eq + Ord,
+{
+	use std::marker::PhantomData;
+
+	use serde::de::{SeqAccess, Visitor};
+
+	struct BTreeSetVisitor<V> {
+		item: PhantomData<V>,
+	}
+
+	impl<'de, V> Visitor<'de> for BTreeSetVisitor<V>
+	where
+		V: Deserialize<'de> + Hash + Eq + Ord,
+	{
+		type Value = BTreeSet<V>;
+
+		fn expecting(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+			write!(formatter, "a sequence")
+		}
+
+		fn visit_seq<A>(self, mut seq: A) -> Result<Self::Value, A::Error>
+		where
+			A: SeqAccess<'de>,
+		{
+			let mut set = BTreeSet::new();
+
+			while let Some(element) = seq.next_element().transpose() {
+				if let Ok(element) = element {
+					set.insert(element);
+				}
+			}
+
+			Ok(set)
+		}
+	}
+
+	de.deserialize_seq(BTreeSetVisitor { item: PhantomData })
+}
+
+fn is_subdomain(subdomain: &str, domain: &str) -> bool {
+	if subdomain == domain {
+		return true;
+	}
+
+	subdomain.ends_with(&format!(".{domain}"))
+}

src/service/oauth/grant.rs

@@ -0,0 +1,211 @@
+use std::{
+	borrow::Cow,
+	collections::BTreeSet,
+	error::Error,
+	fmt::{Debug, Display},
+	hash::Hash,
+	mem::discriminant,
+};
+
+use regex::Regex;
+use ruma::OwnedDeviceId;
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+use super::client_metadata::ResponseType;
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct AuthorizationCodeQuery {
+	pub response_type: ResponseType,
+	pub client_id: String,
+	pub redirect_uri: Url,
+	pub scope: RawScopes,
+	pub state: String,
+	#[serde(default)]
+	pub response_mode: ResponseMode,
+	pub code_challenge: String,
+	pub code_challenge_method: CodeChallengeMethod,
+	#[serde(default)]
+	pub prompt: Option<Prompt>,
+}
+
+#[derive(Debug, Clone, Default, Deserialize, Serialize)]
+#[serde(rename_all = "snake_case")]
+#[non_exhaustive]
+pub enum ResponseMode {
+	#[default]
+	// default for `code` response type, see https://openid.net/specs/oauth-v2-multiple-response-types-1_0.html#:~:text=Client%2E-,For,encoding%2E,-See
+	Query,
+	Fragment,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[non_exhaustive]
+pub enum CodeChallengeMethod {
+	S256,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+#[serde(rename_all = "snake_case")]
+#[non_exhaustive]
+pub enum Prompt {
+	Create,
+	#[serde(other)]
+	Unknown,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize, PartialOrd, Ord)]
+pub enum Scope {
+	Device(OwnedDeviceId),
+	ClientApi,
+}
+
+impl PartialEq for Scope {
+	fn eq(&self, other: &Self) -> bool { discriminant(self) == discriminant(other) }
+}
+
+impl Eq for Scope {}
+
+impl Hash for Scope {
+	fn hash<H: std::hash::Hasher>(&self, state: &mut H) { discriminant(self).hash(state); }
+}
+
+impl Display for Scope {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		let urn = match self {
+			| Self::ClientApi => "urn:matrix:client:api:*".to_owned(),
+			| Self::Device(device_id) => format!("urn:matrix:client:device:{device_id}"),
+		};
+
+		f.write_str(&urn)
+	}
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct RawScopes(String);
+
+impl RawScopes {
+	pub fn to_scopes(&self) -> Result<BTreeSet<Scope>, String> {
+		let client_api_token_regex =
+			Regex::new(r"urn:matrix:(client|org.matrix.msc2967.client):api:\*").unwrap();
+		let device_token_regex = Regex::new(
+			r"urn:matrix:(client|org.matrix.msc2967.client):device:([a-zA-Z0-9-._~]{5,})",
+		)
+		.unwrap();
+
+		let mut scopes = BTreeSet::new();
+
+		for token in self.0.split(' ') {
+			let scope_was_new = {
+				if client_api_token_regex.is_match(token) {
+					scopes.insert(Scope::ClientApi)
+				} else if let Some(captures) = device_token_regex.captures(token) {
+					scopes.insert(Scope::Device(captures.get(2).unwrap().as_str().into()))
+				} else if token == "openid" {
+					// TODO(unspecced): Element sets this scope but doesn't use it for anything
+					true
+				} else {
+					return Err(format!("Invalid scope: {token}"));
+				}
+			};
+
+			if !scope_was_new {
+				return Err("Scope was specified more than once".to_owned());
+			}
+		}
+
+		Ok(scopes)
+	}
+}
+
+#[derive(Serialize, Debug, Clone)]
+pub struct OAuthError {
+	pub error: ErrorCode,
+	pub error_description: Cow<'static, str>,
+}
+
+impl OAuthError {
+	#[must_use]
+	pub const fn invalid_request(error_description: &'static str) -> Self {
+		Self {
+			error: ErrorCode::InvalidRequest,
+			error_description: Cow::Borrowed(error_description),
+		}
+	}
+
+	#[must_use]
+	pub const fn invalid_grant(error_description: &'static str) -> Self {
+		Self {
+			error: ErrorCode::InvalidGrant,
+			error_description: Cow::Borrowed(error_description),
+		}
+	}
+}
+
+impl Display for OAuthError {
+	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+		write!(f, "OAuth error {:?}: {}", self.error, self.error_description)
+	}
+}
+
+impl Error for OAuthError {}
+
+#[derive(Serialize, Debug, Clone, Copy, PartialEq, Eq)]
+#[serde(rename_all = "snake_case")]
+pub enum ErrorCode {
+	InvalidRequest,
+	AccessDenied,
+	InvalidScope,
+	InvalidGrant,
+	InvalidClientMetadata,
+}
+
+#[derive(Serialize)]
+pub struct AuthorizationCodeResponse {
+	pub state: String,
+	pub code: String,
+}
+
+#[derive(Deserialize)]
+#[serde(tag = "grant_type", rename_all = "snake_case")]
+pub enum TokenRequest {
+	AuthorizationCode {
+		code: String,
+		redirect_uri: Url,
+		client_id: String,
+		code_verifier: String,
+	},
+	RefreshToken {
+		client_id: String,
+		refresh_token: String,
+	},
+}
+
+impl TokenRequest {
+	#[must_use]
+	pub fn client_id(&self) -> &str {
+		match self {
+			| Self::AuthorizationCode { client_id, .. }
+			| Self::RefreshToken { client_id, .. } => client_id,
+		}
+	}
+}
+
+#[derive(Serialize)]
+pub struct TokenResponse {
+	pub access_token: String,
+	pub token_type: TokenType,
+	pub expires_in: u64,
+	pub refresh_token: String,
+	pub scope: String,
+}
+
+#[derive(Serialize)]
+pub enum TokenType {
+	Bearer,
+}
+
+#[derive(Deserialize)]
+pub struct RevokeTokenRequest {
+	pub token: String,
+}

src/service/oauth/mod.rs

@@ -0,0 +1,528 @@
+use std::{
+	collections::{BTreeSet, HashMap},
+	sync::{Arc, Mutex},
+	time::{Duration, SystemTime},
+};
+
+use base64::Engine;
+use conduwuit::{
+	Result, info,
+	utils::{self, hash::sha256},
+};
+use database::{Deserialized, Json, Map};
+use itertools::Itertools;
+use lru_cache::LruCache;
+use ruma::{DeviceId, OwnedDeviceId, OwnedUserId, UserId};
+use serde::{Deserialize, Serialize};
+use url::Url;
+
+use crate::{
+	Dep,
+	oauth::{
+		client_metadata::{ApplicationType, ClientMetadata, ResponseType},
+		grant::{
+			AuthorizationCodeQuery, AuthorizationCodeResponse, CodeChallengeMethod, ErrorCode,
+			OAuthError, ResponseMode, Scope, TokenRequest, TokenResponse, TokenType,
+		},
+	},
+	users,
+};
+
+pub mod client_metadata;
+pub mod grant;
+
+pub struct Service {
+	services: Services,
+	db: Data,
+	tickets: Mutex<HashMap<String, HashMap<OAuthTicket, SystemTime>>>,
+	pending_code_grants: tokio::sync::Mutex<LruCache<String, PendingCodeGrant>>,
+}
+
+struct Data {
+	clientid_clientmetadata: Arc<Map>,
+	userdeviceid_oauthsessioninfo: Arc<Map>,
+	refreshtoken_refreshtokeninfo: Arc<Map>,
+}
+
+struct Services {
+	users: Dep<users::Service>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+pub struct SessionInfo {
+	pub client_id: String,
+	pub scopes: BTreeSet<Scope>,
+	current_refresh_token: String,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+struct RefreshTokenInfo {
+	client_id: String,
+	user_id: OwnedUserId,
+	device_id: OwnedDeviceId,
+}
+
+struct PendingCodeGrant {
+	authorizing_user: OwnedUserId,
+	requested_scopes: BTreeSet<Scope>,
+	client_name: Option<String>,
+	expected_client_id: String,
+	expected_redirect_uri: Url,
+	code_challenge: String,
+	requested_at: SystemTime,
+}
+
+impl PendingCodeGrant {
+	const MAX_AGE: Duration = Duration::from_mins(1);
+	const RANDOM_CODE_LENGTH: usize = 32;
+
+	#[must_use]
+	pub(crate) fn generate_code() -> String { utils::random_string(Self::RANDOM_CODE_LENGTH) }
+
+	#[must_use]
+	pub(crate) fn is_valid_for(&self, client_id: &str) -> bool {
+		let now = SystemTime::now();
+
+		self.expected_client_id == client_id
+			&& now
+				.duration_since(self.requested_at)
+				.is_ok_and(|age| age < Self::MAX_AGE)
+	}
+}
+
+/// A time-limited grant for a client to perform some sensitive action.
+#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum OAuthTicket {
+	CrossSigningReset,
+}
+
+impl OAuthTicket {
+	const MAX_AGE: Duration = Duration::from_mins(10);
+
+	#[must_use]
+	pub fn ticket_issue_path(&self) -> &'static str {
+		match self {
+			| Self::CrossSigningReset => "/account/cross_signing_reset",
+		}
+	}
+}
+
+impl crate::Service for Service {
+	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
+		Ok(Arc::new(Self {
+			services: Services {
+				users: args.depend::<users::Service>("users"),
+			},
+			db: Data {
+				clientid_clientmetadata: args.db["clientid_clientmetadata"].clone(),
+				userdeviceid_oauthsessioninfo: args.db["userdeviceid_oauthsessioninfo"].clone(),
+				refreshtoken_refreshtokeninfo: args.db["refreshtoken_refreshtokeninfo"].clone(),
+			},
+			tickets: Mutex::default(),
+			pending_code_grants: tokio::sync::Mutex::new(LruCache::new(
+				Self::MAX_PENDING_CODE_GRANTS,
+			)),
+		}))
+	}
+
+	fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
+}
+
+impl Service {
+	const ACCESS_TOKEN_MAX_AGE: Duration = Duration::from_hours(1);
+	// Maximum number of pending code grants which will be held in memory at once,
+	// to prevent unbounded memory use if someone decides to repeatedly reload the
+	// grant page.
+	const MAX_PENDING_CODE_GRANTS: usize = 100;
+	const RANDOM_TOKEN_LENGTH: usize = 32;
+
+	fn generate_token() -> String { utils::random_string(Self::RANDOM_TOKEN_LENGTH) }
+
+	pub async fn register_client(&self, metadata: &ClientMetadata) -> Result<String, OAuthError> {
+		metadata.validate().map_err(|error| OAuthError {
+			error: ErrorCode::InvalidClientMetadata,
+			error_description: error.into(),
+		})?;
+
+		let client_id = base64::prelude::BASE64_STANDARD
+			.encode(sha256::hash(serde_json::to_string(metadata).unwrap().as_bytes()));
+
+		if self
+			.db
+			.clientid_clientmetadata
+			.exists(&client_id)
+			.await
+			.is_err()
+		{
+			self.db
+				.clientid_clientmetadata
+				.raw_put(&client_id, Json(metadata.clone()));
+		}
+
+		Ok(client_id)
+	}
+
+	pub async fn get_client_metadata(&self, client_id: &str) -> Option<ClientMetadata> {
+		self.db
+			.clientid_clientmetadata
+			.get(client_id)
+			.await
+			.deserialized()
+			.ok()
+	}
+
+	pub async fn get_session_info_for_device(
+		&self,
+		user_id: &UserId,
+		device_id: &DeviceId,
+	) -> Option<SessionInfo> {
+		self.db
+			.userdeviceid_oauthsessioninfo
+			.qry(&(user_id, device_id))
+			.await
+			.deserialized::<SessionInfo>()
+			.ok()
+	}
+
+	pub async fn request_authorization_code(
+		&self,
+		authorizing_user: OwnedUserId,
+		query: AuthorizationCodeQuery,
+	) -> Result<String, String> {
+		let Some(client_metadata) = self.get_client_metadata(&query.client_id).await else {
+			return Err("Invalid client ID".to_owned());
+		};
+
+		if !(client_metadata
+			.response_types
+			.contains(&query.response_type)
+			&& matches!(query.response_type, ResponseType::Code))
+		{
+			return Err("Invalid response type".to_owned());
+		}
+
+		if !matches!(query.code_challenge_method, CodeChallengeMethod::S256) {
+			return Err("Invalid code challenge type".to_owned());
+		}
+
+		{
+			let mut stripped_uri = query.redirect_uri.clone();
+
+			if client_metadata.application_type == ApplicationType::Native
+				&& query
+					.redirect_uri
+					.host_str()
+					.is_some_and(|host| ClientMetadata::ACCEPTABLE_LOCALHOSTS.contains(&host))
+			{
+				// Remove the port from localhost redirect URIs for native applications when
+				// checking if it's valid
+				stripped_uri.set_port(None).unwrap();
+			}
+
+			if !client_metadata.redirect_uris.contains(&stripped_uri) {
+				return Err("Invalid redirect URI".to_owned());
+			}
+		}
+
+		let requested_scopes = query.scope.to_scopes()?;
+
+		let redirect_uri_query_separator = match query.response_mode {
+			| ResponseMode::Fragment => '#',
+			| ResponseMode::Query => '?',
+		};
+
+		let code = PendingCodeGrant::generate_code();
+
+		info!(
+			client_id = &query.client_id,
+			client_name = &client_metadata.client_name,
+			?requested_scopes,
+			?authorizing_user,
+			"Issuing oauth authorization code"
+		);
+
+		let redirect_uri = format!(
+			"{}{}{}",
+			query.redirect_uri,
+			redirect_uri_query_separator,
+			serde_urlencoded::to_string(AuthorizationCodeResponse {
+				state: query.state,
+				code: code.clone(),
+			})
+			.unwrap(),
+		);
+
+		let pending_grant = PendingCodeGrant {
+			authorizing_user,
+			requested_scopes,
+			client_name: client_metadata.client_name,
+			expected_client_id: query.client_id,
+			expected_redirect_uri: query.redirect_uri,
+			code_challenge: query.code_challenge,
+			requested_at: SystemTime::now(),
+		};
+
+		self.pending_code_grants
+			.lock()
+			.await
+			.insert(code, pending_grant);
+
+		Ok(redirect_uri)
+	}
+
+	pub async fn issue_token(&self, request: TokenRequest) -> Result<TokenResponse, OAuthError> {
+		match request {
+			| TokenRequest::AuthorizationCode {
+				code,
+				redirect_uri,
+				client_id,
+				code_verifier,
+			} => {
+				let mut pending_grants = self.pending_code_grants.lock().await;
+
+				let Some(pending_grant) = pending_grants
+					.remove(&code)
+					.filter(|grant| grant.is_valid_for(&client_id))
+				else {
+					return Err(OAuthError::invalid_grant("Invalid authorization code"));
+				};
+
+				if redirect_uri != pending_grant.expected_redirect_uri {
+					return Err(OAuthError::invalid_grant("Invalid redirect URI"));
+				}
+
+				let expected_code_challenge =
+					base64::prelude::BASE64_URL_SAFE_NO_PAD.encode(sha256::hash(&code_verifier));
+				if expected_code_challenge != pending_grant.code_challenge {
+					return Err(OAuthError::invalid_grant("Invalid code challenge"));
+				}
+
+				self.create_session(
+					pending_grant.authorizing_user,
+					pending_grant.requested_scopes,
+					pending_grant.client_name,
+					client_id,
+				)
+				.await
+			},
+			| TokenRequest::RefreshToken { client_id, refresh_token } =>
+				self.refresh_session(client_id, refresh_token).await,
+		}
+	}
+
+	pub async fn revoke_token(&self, token: String) -> Result<(), OAuthError> {
+		let (user_id, device_id) = if let Ok(refresh_token_info) = self
+			.db
+			.refreshtoken_refreshtokeninfo
+			.get(&token)
+			.await
+			.deserialized::<RefreshTokenInfo>()
+		{
+			(refresh_token_info.user_id, refresh_token_info.device_id)
+		} else if let Some((user_id, device_id, _)) =
+			self.services.users.find_from_token(&token).await
+		{
+			(user_id, device_id)
+		} else {
+			return Err(OAuthError::invalid_grant("Invalid access or refersh token"));
+		};
+
+		// This will also call [`Self::remove_session`]
+		self.services
+			.users
+			.remove_device(&user_id, &device_id)
+			.await;
+
+		Ok(())
+	}
+
+	async fn create_session(
+		&self,
+		authorizing_user: OwnedUserId,
+		requested_scopes: BTreeSet<Scope>,
+		client_name: Option<String>,
+		client_id: String,
+	) -> Result<TokenResponse, OAuthError> {
+		let access_token = Self::generate_token();
+		let refresh_token = Self::generate_token();
+
+		let device_id = requested_scopes
+			.iter()
+			.find_map(|scope| {
+				if let Scope::Device(device_id) = scope {
+					Some(device_id)
+				} else {
+					None
+				}
+			})
+			.ok_or_else(|| OAuthError::invalid_grant("No device ID scope supplied"))?;
+
+		if self
+			.services
+			.users
+			.get_device_metadata(&authorizing_user, device_id)
+			.await
+			.is_ok()
+		{
+			return Err(OAuthError {
+				error: ErrorCode::InvalidScope,
+				error_description: "A device with the supplied ID already exists for this user"
+					.into(),
+			});
+		}
+
+		self.services
+			.users
+			.create_device(
+				&authorizing_user,
+				device_id,
+				&access_token,
+				Some(Self::ACCESS_TOKEN_MAX_AGE),
+				client_name,
+				None,
+			)
+			.await
+			// This can only panic if the authorizing user suffered a spontaneous existence
+			// failure during authentication, which should(?) be impossible(?)
+			.expect("failed to create device");
+
+		self.db.userdeviceid_oauthsessioninfo.put(
+			(&authorizing_user, device_id),
+			Json(SessionInfo {
+				client_id: client_id.clone(),
+				current_refresh_token: refresh_token.clone(),
+				scopes: requested_scopes.clone(),
+			}),
+		);
+
+		self.db.refreshtoken_refreshtokeninfo.raw_put(
+			&refresh_token,
+			Json(RefreshTokenInfo {
+				client_id: client_id.clone(),
+				user_id: authorizing_user.clone(),
+				device_id: device_id.to_owned(),
+			}),
+		);
+
+		info!(
+			?client_id,
+			?authorizing_user,
+			?device_id,
+			?requested_scopes,
+			"Created new oauth session"
+		);
+
+		Ok(TokenResponse {
+			access_token,
+			token_type: TokenType::Bearer,
+			expires_in: Self::ACCESS_TOKEN_MAX_AGE.as_secs(),
+			scope: requested_scopes.iter().join(" "),
+			refresh_token,
+		})
+	}
+
+	async fn refresh_session(
+		&self,
+		client_id: String,
+		refresh_token: String,
+	) -> Result<TokenResponse, OAuthError> {
+		let Some(refresh_token_info) = self
+			.db
+			.refreshtoken_refreshtokeninfo
+			.get(&refresh_token)
+			.await
+			.deserialized::<RefreshTokenInfo>()
+			.ok()
+		else {
+			return Err(OAuthError::invalid_grant("Invalid refresh token"));
+		};
+
+		assert_eq!(&client_id, &refresh_token_info.client_id, "refresh token client id mismatch");
+
+		let mut session_info = self
+			.get_session_info_for_device(
+				&refresh_token_info.user_id,
+				&refresh_token_info.device_id,
+			)
+			.await
+			.expect("session info should exist");
+
+		assert_eq!(&client_id, &session_info.client_id, "session info client id mismatch");
+
+		let new_access_token = Self::generate_token();
+		let new_refresh_token = Self::generate_token();
+		let scope = session_info.scopes.iter().join(" ");
+		session_info
+			.current_refresh_token
+			.clone_from(&new_refresh_token);
+
+		self.services
+			.users
+			.set_token(
+				&refresh_token_info.user_id,
+				&refresh_token_info.device_id,
+				&new_access_token,
+				Some(Self::ACCESS_TOKEN_MAX_AGE),
+			)
+			.await
+			.expect("should be able to set token");
+
+		self.db.userdeviceid_oauthsessioninfo.put(
+			(&refresh_token_info.user_id, &refresh_token_info.device_id),
+			Json(session_info),
+		);
+
+		self.db.refreshtoken_refreshtokeninfo.remove(&refresh_token);
+		drop(refresh_token);
+		self.db
+			.refreshtoken_refreshtokeninfo
+			.raw_put(&new_refresh_token, Json(refresh_token_info));
+
+		Ok(TokenResponse {
+			access_token: new_access_token,
+			token_type: TokenType::Bearer,
+			expires_in: Self::ACCESS_TOKEN_MAX_AGE.as_secs(),
+			scope,
+			refresh_token: new_refresh_token,
+		})
+	}
+
+	pub async fn remove_session(&self, user_id: &UserId, device_id: &DeviceId) {
+		let session_info = self.get_session_info_for_device(user_id, device_id).await;
+
+		if let Some(session_info) = session_info {
+			self.db
+				.refreshtoken_refreshtokeninfo
+				.remove(&session_info.current_refresh_token);
+			self.db
+				.userdeviceid_oauthsessioninfo
+				.del((user_id, device_id));
+			info!(?user_id, ?device_id, "Removed OAuth session");
+		}
+	}
+
+	/// Issue a ticket for `localpart` to perform some action.
+	pub fn issue_ticket(&self, localpart: String, ticket: OAuthTicket) {
+		self.tickets
+			.lock()
+			.unwrap()
+			.entry(localpart)
+			.or_default()
+			.insert(ticket, SystemTime::now());
+	}
+
+	/// Try to consume an unexpired ticket for `localpart`.
+	pub fn try_consume_ticket(&self, localpart: &str, ticket: OAuthTicket) -> bool {
+		let now = SystemTime::now();
+
+		self.tickets
+			.lock()
+			.unwrap()
+			.get_mut(localpart)
+			.and_then(|tickets| tickets.remove(&ticket))
+			.is_some_and(|issued| {
+				now.duration_since(issued)
+					.is_ok_and(|duration| duration < OAuthTicket::MAX_AGE)
+			})
+	}
+}

src/service/password_reset/data.rs

@@ -1,68 +0,0 @@
-use std::{
-	sync::Arc,
-	time::{Duration, SystemTime},
-};
-
-use conduwuit::utils::{ReadyExt, stream::TryExpect};
-use database::{Database, Deserialized, Json, Map};
-use ruma::{OwnedUserId, UserId};
-use serde::{Deserialize, Serialize};
-
-pub(super) struct Data {
-	passwordresettoken_info: Arc<Map>,
-}
-
-#[derive(Debug, Serialize, Deserialize)]
-pub struct ResetTokenInfo {
-	pub user: OwnedUserId,
-	pub issued_at: SystemTime,
-}
-
-impl ResetTokenInfo {
-	// one hour
-	const MAX_TOKEN_AGE: Duration = Duration::from_hours(1);
-
-	pub fn is_valid(&self) -> bool {
-		let now = SystemTime::now();
-
-		now.duration_since(self.issued_at)
-			.is_ok_and(|duration| duration < Self::MAX_TOKEN_AGE)
-	}
-}
-
-impl Data {
-	pub(super) fn new(db: &Arc<Database>) -> Self {
-		Self {
-			passwordresettoken_info: db["passwordresettoken_info"].clone(),
-		}
-	}
-
-	/// Associate a reset token with its info in the database.
-	pub(super) fn save_token(&self, token: &str, info: &ResetTokenInfo) {
-		self.passwordresettoken_info.raw_put(token, Json(info));
-	}
-
-	/// Lookup the info for a reset token.
-	pub(super) async fn lookup_token_info(&self, token: &str) -> Option<ResetTokenInfo> {
-		self.passwordresettoken_info
-			.get(token)
-			.await
-			.deserialized()
-			.ok()
-	}
-
-	/// Find a user's existing reset token, if any.
-	pub(super) async fn find_token_for_user(
-		&self,
-		user: &UserId,
-	) -> Option<(String, ResetTokenInfo)> {
-		self.passwordresettoken_info
-			.stream::<'_, String, ResetTokenInfo>()
-			.expect_ok()
-			.ready_find(|(_, info)| info.user == user)
-			.await
-	}
-
-	/// Remove a reset token.
-	pub(super) fn remove_token(&self, token: &str) { self.passwordresettoken_info.remove(token); }
-}

src/service/password_reset/mod.rs

@@ -1,111 +0,0 @@
-mod data;
-
-use std::{sync::Arc, time::SystemTime};
-
-use conduwuit::{Err, Result, utils};
-use data::{Data, ResetTokenInfo};
-use ruma::OwnedUserId;
-
-use crate::{
-	Dep, globals,
-	users::{self, HashedPassword},
-};
-
-pub const PASSWORD_RESET_PATH: &str = "/_continuwuity/account/reset_password";
-pub const RESET_TOKEN_QUERY_PARAM: &str = "token";
-const RESET_TOKEN_LENGTH: usize = 32;
-
-pub struct Service {
-	db: Data,
-	services: Services,
-}
-
-struct Services {
-	users: Dep<users::Service>,
-	globals: Dep<globals::Service>,
-}
-
-#[derive(Debug)]
-pub struct ValidResetToken {
-	pub token: String,
-	pub info: ResetTokenInfo,
-}
-
-impl crate::Service for Service {
-	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
-		Ok(Arc::new(Self {
-			db: Data::new(args.db),
-			services: Services {
-				users: args.depend::<users::Service>("users"),
-				globals: args.depend::<globals::Service>("globals"),
-			},
-		}))
-	}
-
-	fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
-}
-
-impl Service {
-	/// Generate a random string suitable to be used as a password reset token.
-	#[must_use]
-	pub fn generate_token_string() -> String { utils::random_string(RESET_TOKEN_LENGTH) }
-
-	/// Issue a password reset token for `user`, who must be a local user with
-	/// the `password` origin.
-	pub async fn issue_token(&self, user_id: OwnedUserId) -> Result<ValidResetToken> {
-		if !self.services.globals.user_is_local(&user_id) {
-			return Err!("Cannot issue a password reset token for remote user {user_id}");
-		}
-
-		if user_id == self.services.globals.server_user {
-			return Err!("Cannot issue a password reset token for the server user");
-		}
-
-		if self.services.users.is_deactivated(&user_id).await? {
-			return Err!("Cannot issue a password reset token for deactivated user {user_id}");
-		}
-
-		if let Some((existing_token, _)) = self.db.find_token_for_user(&user_id).await {
-			self.db.remove_token(&existing_token);
-		}
-
-		let token = Self::generate_token_string();
-		let info = ResetTokenInfo {
-			user: user_id,
-			issued_at: SystemTime::now(),
-		};
-
-		self.db.save_token(&token, &info);
-
-		Ok(ValidResetToken { token, info })
-	}
-
-	/// Check if `token` represents a valid, non-expired password reset token.
-	pub async fn check_token(&self, token: &str) -> Option<ValidResetToken> {
-		self.db.lookup_token_info(token).await.and_then(|info| {
-			if info.is_valid() {
-				Some(ValidResetToken { token: token.to_owned(), info })
-			} else {
-				self.db.remove_token(token);
-				None
-			}
-		})
-	}
-
-	/// Consume the supplied valid token, using it to change its user's password
-	/// to `new_password`.
-	pub async fn consume_token(
-		&self,
-		ValidResetToken { token, info }: ValidResetToken,
-		new_password: &str,
-	) -> Result<()> {
-		if info.is_valid() {
-			self.db.remove_token(&token);
-			self.services
-				.users
-				.set_password(&info.user, Some(HashedPassword::new(new_password)?));
-		}
-
-		Ok(())
-	}
-}

src/service/presence/mod.rs

@@ -100,7 +100,7 @@ pub async fn get_presence(&self, user_id: &UserId) -> Result<PresenceEvent> {
 	/// Pings the presence of the given user in the given room, setting the
 	/// specified state.
 	pub async fn ping_presence(&self, user_id: &UserId, new_state: &PresenceState) -> Result<()> {
-		const REFRESH_TIMEOUT: u64 = 60 * 1000;
+		const REFRESH_TIMEOUT: u64 = 60 * 1000 * 4;
 
 		let last_presence = self.db.get_presence(user_id).await;
 		let state_changed = match last_presence {

src/service/registration_tokens/mod.rs

@@ -10,6 +10,7 @@
 	stream::{iter, once},
 };
 use ruma::OwnedUserId;
+use serde::{Deserialize, Serialize};
 
 use crate::{Dep, config, firstrun};
 
@@ -27,7 +28,7 @@ struct Services {
 }
 
 /// A validated registration token which may be used to create an account.
-#[derive(Debug)]
+#[derive(Debug, Deserialize, Serialize)]
 pub struct ValidToken {
 	pub token: String,
 	pub source: ValidTokenSource,
@@ -44,7 +45,7 @@ fn eq(&self, other: &str) -> bool { self.token == other }
 }
 
 /// The source of a valid database token.
-#[derive(Debug)]
+#[derive(Debug, Deserialize, Serialize)]
 pub enum ValidTokenSource {
 	/// The static token set in the homeserver's config file.
 	Config,

src/service/rooms/event_handler/fetch_and_handle_outliers.rs

@@ -1,233 +1,667 @@
 use std::{
-	collections::{BTreeMap, HashSet, VecDeque, hash_map},
+	collections::{HashMap, HashSet, VecDeque},
 	time::Instant,
 };
 
+use assign::assign;
+#[cfg(debug_assertions)]
+use conduwuit::error;
 use conduwuit::{
-	Event, PduEvent, debug, debug_warn, implement, matrix::event::gen_event_id_canonical_json,
-	trace, utils::continue_exponential_backoff_secs, warn,
+	Err, Event, PduEvent, debug, debug_error, debug_info, debug_warn, err,
+	state_res::lexicographical_topological_sort,
+	trace,
+	utils::{IterStream, math::Expected, stream::BroadbandExt},
+	warn,
 };
+use futures::{StreamExt, future::select_ok};
 use ruma::{
-	CanonicalJsonValue, EventId, OwnedEventId, RoomId, ServerName,
-	api::federation::event::get_event,
+	CanonicalJsonObject, CanonicalJsonValue, EventId, MilliSecondsSinceUnixEpoch, OwnedEventId,
+	OwnedServerName, RoomId, ServerName, UInt,
+	api::federation::event::{get_event, get_missing_events},
+	int,
+	room_version_rules::RoomVersionRules,
 };
 
 use super::get_room_version_rules;
+use crate::rooms::event_handler::parse_incoming_pdu::expect_event_id_array;
 
-/// Find the event and auth it. Once the event is validated (steps 1 - 8)
-/// it is appended to the outliers Tree.
+pub const GET_MISSING_EVENTS_MAX_BATCH_SIZE: usize = 50;
+
+/// Attempts to build a localised directed acyclic graph out of the given PDUs,
+/// returning them in a topologically sorted order.
 ///
-/// Returns pdu and if we fetched it over federation the raw json.
-///
-/// a. Look in the main timeline (pduid_pdu tree)
-/// b. Look at outlier pdu tree
-/// c. Ask origin server over federation
-/// d. TODO: Ask other servers over federation?
-#[implement(super::Service)]
-pub(super) async fn fetch_and_handle_outliers<'a, Pdu, Events>(
-	&self,
-	origin: &'a ServerName,
-	events: Events,
-	create_event: &'a Pdu,
-	room_id: &'a RoomId,
-) -> Vec<(PduEvent, Option<BTreeMap<String, CanonicalJsonValue>>)>
-where
-	Pdu: Event + Send + Sync,
-	Events: Iterator<Item = &'a EventId> + Clone + Send,
-{
-	let back_off = |id| match self
-		.services
-		.globals
-		.bad_event_ratelimiter
-		.write()
-		.entry(id)
-	{
-		| hash_map::Entry::Vacant(e) => {
-			e.insert((Instant::now(), 1));
-		},
-		| hash_map::Entry::Occupied(mut e) => {
-			*e.get_mut() = (Instant::now(), e.get().1.saturating_add(1));
-		},
-	};
+/// This is used to attempt to process PDUs in an order that respects their
+/// dependencies, however it is ultimately the sender's responsibility to send
+/// them in a processable order, so this is just a best effort attempt. It does
+/// not account for power levels or other tie breaks.
+pub async fn build_local_dag<S: std::hash::BuildHasher + Send + Sync>(
+	pdu_map: &HashMap<OwnedEventId, &CanonicalJsonObject, S>,
+) -> conduwuit::Result<Vec<OwnedEventId>> {
+	debug_assert!(pdu_map.len() >= 2, "needless call to build_local_dag with less than 2 PDUs");
+	let mut dag: HashMap<OwnedEventId, HashSet<OwnedEventId>> =
+		HashMap::with_capacity(pdu_map.len());
+	let mut id_origin_ts: HashMap<OwnedEventId, _> = HashMap::with_capacity(pdu_map.len());
 
-	let mut events_with_auth_events = Vec::with_capacity(events.clone().count());
-	trace!("Fetching {} outlier pdus", events.clone().count());
+	for (event_id, value) in pdu_map {
+		// We already checked that these properties are correct in parse_incoming_pdu,
+		// so it's safe to unwrap here.
+		// We also filter to remove any prev_events that are not in this pdu_map, as we
+		// need to have at least one event with zero out degrees for the lexico-topo
+		// sort below. If there are multiple events with omitted prevs, they will be
+		// ordered by timestamp, then event ID. At that point though, it's unlikely to
+		// matter.
+		let prev_events = value
+			.get("prev_events")
+			.unwrap()
+			.as_array()
+			.unwrap()
+			.iter()
+			.map(|v| EventId::parse(v.as_str().unwrap()).unwrap())
+			.filter(|id| pdu_map.contains_key(id))
+			.collect();
 
-	for id in events {
-		// a. Look in the main timeline (pduid_pdu tree)
-		// b. Look at outlier pdu tree
-		// (get_pdu_json checks both)
-		if let Ok(local_pdu) = self.services.timeline.get_pdu(id).await {
-			trace!("Found {id} in main timeline or outlier tree");
-			events_with_auth_events.push((id.to_owned(), Some(local_pdu), vec![]));
-			continue;
-		}
+		dag.insert(event_id.clone(), prev_events);
+		let origin_server_ts = value
+			.get("origin_server_ts")
+			.and_then(CanonicalJsonValue::as_integer)
+			.unwrap_or_default();
+		id_origin_ts.insert(event_id.clone(), origin_server_ts);
+	}
 
-		// c. Ask origin server over federation
-		// We also handle its auth chain here so we don't get a stack overflow in
-		// handle_outlier_pdu.
-		let mut todo_auth_events: VecDeque<_> = [id.to_owned()].into();
-		let mut events_in_reverse_order = Vec::with_capacity(todo_auth_events.len());
+	debug!(count = dag.len(), "Sorting incoming events with partial graph");
+	lexicographical_topological_sort(&dag, &async |node_id| {
+		// Note: we don't bother fetching power levels because that would massively slow
+		// this function down. This is a best-effort attempt to order events correctly
+		// for processing, however ultimately that should be the sender's job.
+		let ts = id_origin_ts
+			.get(&node_id)
+			.copied()
+			.unwrap_or_else(|| int!(0))
+			.to_string()
+			.parse::<u64>()
+			.ok()
+			.and_then(UInt::new)
+			.unwrap_or_default();
+		Ok((int!(0), MilliSecondsSinceUnixEpoch(ts)))
+	})
+	.await
+	.inspect(|sorted| {
+		debug_assert_eq!(
+			sorted.len(),
+			pdu_map.len(),
+			"Sorted graph was not the same size as the input graph"
+		);
+	})
+	.map_err(|e| err!("failed to resolve local graph: {e}"))
+}
 
-		let mut events_all = HashSet::with_capacity(todo_auth_events.len());
-		while let Some(next_id) = todo_auth_events.pop_front() {
-			if let Some((time, tries)) = self
-				.services
-				.globals
-				.bad_event_ratelimiter
-				.read()
-				.get(&*next_id)
-			{
-				// Exponential backoff
-				const MIN_DURATION: u64 = 60 * 2;
-				const MAX_DURATION: u64 = 60 * 60 * 8;
-				if continue_exponential_backoff_secs(
-					MIN_DURATION,
-					MAX_DURATION,
-					time.elapsed(),
-					*tries,
-				) {
-					debug_warn!(
-						tried = ?*tries,
-						elapsed = ?time.elapsed(),
-						"Backing off from {next_id}",
-					);
-					continue;
-				}
-			}
+impl super::Service {
+	/// Uses `POST /_matrix/federation/v1/get_missing_events/{room_id}` to fill
+	/// gaps in the DAG.
+	///
+	/// This function walks backwards from `head`, fetching incrementally (by a
+	/// factor of 10) more events until the remote we're fetching from either
+	/// stops returning new events, or the min_depth is reached.
+	///
+	/// This function does not persist the events, but does validate them. The
+	/// caller is responsible for passing them through handle_incoming_pdu or
+	/// related functions.
+	///
+	/// Only the one `via` is asked for missing events, as multiplexing remotes
+	/// may result in the event tree being walked in a gappy or disordered
+	/// manner.
+	///
+	/// ## Parameters
+	///
+	/// - `room_id`: The room's ID.
+	/// - `head`: The event we are potentially missing prev_events for.
+	/// - `tail`: The most recently known events in the graph (typically forward
+	///   extremities).
+	/// - `via`: The server to ask for missing events.
+	/// - `min_depth`: Don't process events with a `depth` lower than this
+	///   value. Not massively useful, but can help short-circuit infinite loops
+	///   and weird edge paths.
+	#[tracing::instrument(name = "get_missing_events_bulk", skip_all)]
+	pub async fn get_missing_events(
+		&self,
+		room_id: &RoomId,
+		head: &PduEvent,
+		tail: Vec<OwnedEventId>,
+		via: &ServerName,
+		min_depth: UInt,
+	) -> conduwuit::Result<HashMap<OwnedEventId, PduEvent>> {
+		let start = Instant::now();
+		#[cfg(debug_assertions)]
+		{
+			let missing_count = head
+				.prev_events()
+				.stream()
+				.fold(0_u8, |i, event_id| async move {
+					if self.services.timeline.pdu_exists(event_id).await {
+						i.expected_add(1)
+					} else {
+						i
+					}
+				})
+				.await;
+			debug_assert_ne!(
+				missing_count, 0,
+				"event passed to get_missing_events is not missing any events (wasteful call)"
+			);
+		};
+		assert!(!tail.is_empty(), "empty tail");
+		assert_ne!(via, self.services.globals.server_name(), "cannot ask ourselves for events");
 
-			if events_all.contains(&next_id) {
-				continue;
-			}
+		// The iteration limit is in place to ensure that if the remote server leaves us
+		// in a state of infinite recursion (as old versions of continuwuity and
+		// predecessors would), we give up. However, get_missing_events doesn't return
+		// that many events per-request. Synapse returns 20, and conduwuit+ return 50.
+		// This means with a hard iteration limit, we might give up too early, before
+		// we get a chance to even come close to max_fetch_prev_events. As such, we'll
+		// calculate the limit based on that config option and the aforementioned
+		// averages.
+		let max_fetch = self.services.server.config.max_fetch_prev_events;
+		let iteration_limit = max_fetch.saturating_div(20).max(10);
 
-			if self.services.timeline.pdu_exists(&next_id).await {
-				trace!("Found {next_id} in db");
-				continue;
-			}
-
-			debug!("Fetching {next_id} over federation from {origin}.");
-			match self
+		let mut discovered = HashMap::with_capacity(head.prev_events.len());
+		let mut latest_events: Vec<OwnedEventId> = vec![head.event_id().to_owned()];
+		debug!(elapsed=?start.elapsed(),
+			%room_id,
+			event_id=%head.event_id(),
+			%iteration_limit,
+			"Fetching any missing events for head event",
+		);
+		for iteration in 0..iteration_limit {
+			let limit = iteration
+				.expected_add(1)
+				.saturating_mul(10)
+				.min(GET_MISSING_EVENTS_MAX_BATCH_SIZE.try_into().expect(
+					"GET_MISSING_EVENTS_MAX_BATCH_SIZE (usize) should fit in u16 (<=65536)",
+				))
+				.max(
+					// This max call ensures we fetch *at least* all the prev events the
+					// head has.
+					u16::try_from(head.prev_events.len())
+						.expect("cannot have more than 20 prev events, which fits in u16"),
+				);
+			debug_info!(elapsed=?start.elapsed(),
+				%limit,
+				%via,
+				%iteration,
+				%iteration_limit,
+				discovered=discovered.len(),
+				%min_depth,
+				"Attempting to gap fill missing events"
+			);
+			let response: get_missing_events::v1::Response = self
 				.services
 				.sending
 				.send_federation_request(
-					origin,
-					get_event::v1::Request::new((*next_id).to_owned()),
+					via,
+					assign!(
+						get_missing_events::v1::Request::new(
+							room_id.to_owned(),
+							tail.clone(),
+							latest_events.clone()
+						),
+						{limit: limit.into(), min_depth}
+					),
 				)
-				.await
-			{
-				| Ok(res) => {
-					debug!("Got {next_id} over federation from {origin}");
-					let Ok(room_version_rules) = get_room_version_rules(create_event) else {
-						back_off((*next_id).to_owned());
-						continue;
-					};
+				.await?;
 
-					let Ok((calculated_event_id, value)) =
-						gen_event_id_canonical_json(&res.pdu, &room_version_rules)
-					else {
-						back_off((*next_id).to_owned());
-						continue;
-					};
-
-					if calculated_event_id != *next_id {
-						warn!(
-							"Server didn't return event id we requested: requested: {next_id}, \
-							 we got {calculated_event_id}. Event: {:?}",
-							&res.pdu
-						);
-					}
-
-					if let Some(auth_events) = value
-						.get("auth_events")
-						.and_then(CanonicalJsonValue::as_array)
-					{
-						for auth_event in auth_events {
-							match serde_json::from_value::<OwnedEventId>(
-								auth_event.clone().into(),
-							) {
-								| Ok(auth_event) => {
-									trace!(
-										"Found auth event id {auth_event} for event {next_id}"
-									);
-									todo_auth_events.push_back(auth_event);
-								},
-								| _ => {
-									warn!("Auth event id is not valid");
-								},
-							}
-						}
-					} else {
-						warn!("Auth event list invalid");
-					}
-
-					events_in_reverse_order.push((next_id.clone(), value));
-					events_all.insert(next_id);
-				},
-				| Err(e) => {
-					warn!("Failed to fetch auth event {next_id} from {origin}: {e}");
-					back_off((*next_id).to_owned());
-				},
+			if response.events.is_empty() {
+				debug_info!(
+					elapsed=?start.elapsed(),
+					%via,
+					"Finished gap filling missing events (remote returned no more events)."
+				);
+				break;
 			}
-		}
+			debug_info!(
+				elapsed=?start.elapsed(),
+				"Got {} events back from remote",
+				response.events.len()
+			);
 
-		events_with_auth_events.push((id.to_owned(), None, events_in_reverse_order));
-	}
-
-	let mut pdus = Vec::with_capacity(events_with_auth_events.len());
-	for (id, local_pdu, events_in_reverse_order) in events_with_auth_events {
-		// a. Look in the main timeline (pduid_pdu tree)
-		// b. Look at outlier pdu tree
-		// (get_pdu_json checks both)
-		if let Some(local_pdu) = local_pdu {
-			trace!("Found {id} in main timeline or outlier tree");
-			pdus.push((local_pdu.clone(), None));
-		}
-
-		for (next_id, value) in events_in_reverse_order.into_iter().rev() {
-			if let Some((time, tries)) = self
-				.services
-				.globals
-				.bad_event_ratelimiter
-				.read()
-				.get(&*next_id)
-			{
-				// Exponential backoff
-				const MIN_DURATION: u64 = 5 * 60;
-				const MAX_DURATION: u64 = 60 * 60 * 24;
-				if continue_exponential_backoff_secs(
-					MIN_DURATION,
-					MAX_DURATION,
-					time.elapsed(),
-					*tries,
-				) {
-					debug!("Backing off from {next_id}");
+			latest_events.clear();
+			for raw_event in response.events {
+				let (_, event_id, pdu_json) = self.parse_incoming_pdu(&raw_event).await?;
+				let pdu = PduEvent::from_id_val(&event_id, pdu_json).map_err(|e| {
+					err!(Request(BadJson("Failed to parse gapfilled event {event_id}: {e}")))
+				})?;
+				if discovered.contains_key(&event_id) {
+					// We already received this event.
+					trace!("Already received {event_id}");
 					continue;
 				}
+				if self
+					.services
+					.timeline
+					.non_outlier_pdu_exists(&event_id)
+					.await
+				{
+					// NOTE: we explicitly check for *non*-outlier events here, as if we end
+					// up discovering outlier events, we will be able to upgrade them
+					// immediately.
+					trace!("Already have {event_id} as a timeline PDU");
+					continue;
+				}
+
+				if pdu.depth < min_depth {
+					debug_warn!(
+						elapsed=?start.elapsed(),
+						"Received PDU with depth {} below min_depth {}",
+						pdu.depth,
+						min_depth
+					);
+					discovered.insert(event_id.clone(), pdu);
+					continue;
+				}
+
+				for prev_event_id in pdu.prev_events() {
+					if discovered.contains_key(prev_event_id) {
+						// We already received this event.
+						trace!("Already received prev event {prev_event_id}");
+						continue;
+					}
+					if self
+						.services
+						.timeline
+						.non_outlier_pdu_exists(prev_event_id)
+						.await
+					{
+						// NOTE: we explicitly check for *non*-outlier events here, as if we end
+						// up discovering outlier events, we will be able to upgrade them
+						// immediately.
+						trace!("Already have prev event {prev_event_id} as a timeline PDU");
+						continue;
+					}
+					if let Ok(outlier) = self.services.timeline.get_pdu(prev_event_id).await {
+						// We already have this PDU as an outlier, don't ask for
+						// it. However, if we are missing any prev events for it, add it to the
+						// latest events anyway.
+						let outlier_missing_prevs = outlier
+							.prev_events()
+							.stream()
+							.fold(0_u8, |i, event_id| async move {
+								if self.services.timeline.pdu_exists(event_id).await {
+									i.expected_add(1)
+								} else {
+									i
+								}
+							})
+							.await;
+						if outlier_missing_prevs > 0 {
+							trace!("Missing {outlier_missing_prevs} PDU(s) for prev event");
+							latest_events.push(prev_event_id.to_owned());
+						}
+						trace!("Had {prev_event_id} as an outlier already, skipping discovery");
+						discovered.insert(prev_event_id.to_owned(), outlier);
+						continue;
+					}
+					trace!("Missing prev {prev_event_id} of {event_id}");
+					latest_events.push(prev_event_id.to_owned());
+				}
+				trace!("Discovered {event_id}");
+				discovered.insert(event_id.clone(), pdu);
 			}
 
-			trace!("Handling outlier {next_id}");
+			if latest_events.is_empty() {
+				debug!(elapsed=?start.elapsed(),
+					%limit,
+					%via,
+					%iteration,
+					discovered=discovered.len(),
+					"No more events to fetch."
+				);
+				break;
+			}
+			if discovered.len() >= self.services.server.config.max_fetch_prev_events.into() {
+				// Stupid hack, debug_error!() drops the log to a DEBUG when not in debug mode,
+				// which is bad because this should at least produce a warning. It's an error in
+				// debug mode because this can be important, but typically not much can be done
+				// about it as a user.
+				#[cfg(debug_assertions)]
+				error!(elapsed=?start.elapsed(),
+					discovered=discovered.len(),
+					max_fetch_prev_events=self.services.server.config.max_fetch_prev_events,
+					%iteration,
+					%iteration_limit,
+					%via,
+					event_id=%head.event_id(),
+					%room_id,
+					"Encountered a gap too large to fill, giving up"
+				);
+				#[cfg(not(debug_assertions))]
+				warn!(elapsed=?start.elapsed(),
+					discovered=discovered.len(),
+					max_fetch_prev_events=self.services.server.config.max_fetch_prev_events,
+					%iteration,
+					%iteration_limit,
+					%via,
+					event_id=%head.event_id(),
+					%room_id,
+					"Encountered a gap too large to fill"
+				);
+				break;
+			}
+		}
+
+		trace!(elapsed=?start.elapsed(), "Finished get_missing_events");
+		Ok(discovered)
+	}
+
+	/// Sends a `GET /_matrix/federation/v1/event/{event_id}` request to the
+	/// target `remote`, parses the resulting PDU, and ensures the remote
+	/// returned the correct event.
+	/// Allows `fetch_and_handle_missing_events` to atomically fetch events from
+	/// multiple remotes in parallel.
+	async fn fetch_event_via(
+		&self,
+		remote: OwnedServerName,
+		event_id: OwnedEventId,
+		room_version_rules: &RoomVersionRules,
+	) -> conduwuit::Result<(OwnedEventId, CanonicalJsonObject)> {
+		let res = self
+			.services
+			.sending
+			.send_federation_request(&remote, get_event::v1::Request::new(event_id.clone()))
+			.await?;
+
+		let (calculated_event_id, value) = self
+			.parse_incoming_pdu_with_known_room(&res.pdu, room_version_rules)
+			.await?;
+
+		if calculated_event_id != event_id {
+			Err!(Request(BadJson(warn!(
+				expected=%event_id,
+				received=%calculated_event_id,
+				"Server didn't return event id we requested",
+			))))
+		} else {
+			Ok((event_id, value))
+		}
+	}
+
+	async fn fetch_event_vias(
+		&self,
+		candidates: impl Iterator<Item = &OwnedServerName>,
+		event_id: &EventId,
+		room_version_rules: &RoomVersionRules,
+	) -> conduwuit::Result<(OwnedEventId, CanonicalJsonObject)> {
+		if let Ok(pdu_json) = self.services.timeline.get_pdu_json(event_id).await {
+			return Ok((event_id.to_owned(), pdu_json));
+		}
+		let futures = candidates
+			.map(|remote| {
+				Box::pin(self.fetch_event_via(
+					remote.to_owned(),
+					event_id.to_owned(),
+					room_version_rules,
+				))
+			})
+			.collect::<Vec<_>>();
+		select_ok(futures).await.map(|(res, _)| res)
+	}
+
+	/// Asks remote servers for any individual events that are missing, also
+	/// known as "atomic fetch". Should only be used for fetching missing auth
+	/// events or resolving missing events from state_ids. For all other uses,
+	/// use get_missing_events.
+	///
+	/// This function manually walks auth_events trees in a breadth-first
+	/// search, and persists all fetched events as outliers when all the
+	/// backwards extremities have been resolved.
+	#[tracing::instrument(name = "get_missing_auth_events_atomic", skip_all)]
+	pub(super) async fn fetch_and_handle_auth_events<Pdu>(
+		&self,
+		origin: &ServerName,
+		events: Vec<OwnedEventId>,
+		create_event: &Pdu,
+		room_id: &RoomId,
+	) -> HashMap<OwnedEventId, PduEvent>
+	where
+		Pdu: Event + Send + Sync,
+	{
+		let start = Instant::now();
+		let room_version_rules =
+			&get_room_version_rules(create_event).unwrap_or(RoomVersionRules::V1);
+		let mut candidates = self
+			.services
+			.timeline
+			.candidate_backfill_servers(room_id)
+			.await;
+		candidates.insert(origin.to_owned());
+		assert!(!candidates.is_empty(), "no candidates to fetch missing events from");
+		let mut discovered_events =
+			HashMap::with_capacity(events.len().saturating_add(events.len().saturating_mul(3)));
+		trace!(
+			elapsed=?start.elapsed(),
+			"Fetching {} unknown PDUs on demand from {} candidates",
+			events.len(),
+			candidates.len()
+		);
+
+		let mut seen: HashMap<OwnedEventId, u8> = HashMap::new();
+		for apex_event_id in &events {
+			let mut todo: VecDeque<OwnedEventId> = [apex_event_id.to_owned()].into();
+
+			while let Some(target_id) = todo.pop_front() {
+				if discovered_events.contains_key(&target_id) {
+					continue;
+				}
+				if let Ok(local_pdu) = self.services.timeline.get_pdu(&target_id).await {
+					trace!(elapsed=?start.elapsed(), "Found {target_id} in db");
+					let mut obj = local_pdu.into_canonical_object();
+					obj.remove("event_id");
+					discovered_events.insert(target_id.clone(), obj);
+					continue;
+				}
+				let attempts = seen.get(&*target_id).copied().unwrap_or_default();
+				if attempts >= 5 {
+					debug_error!(
+						elapsed=?start.elapsed(),
+						%attempts,
+						%target_id,
+						"Could not fetch missing event after 5 attempts, giving up"
+					);
+					continue;
+				}
+
+				debug!(elapsed=?start.elapsed(),"Fetching {target_id} over federation");
+				let value = match self
+					.fetch_event_vias(candidates.iter(), &target_id, room_version_rules)
+					.await
+				{
+					| Ok((_, x)) => x,
+					| Err(e) => {
+						warn!(elapsed=?start.elapsed(),"failed to fetch missing event {target_id} from any candidate: {e}");
+						continue;
+					},
+				};
+				let auth_events =
+					match expect_event_id_array(&value, "auth_events").map_err(|e| {
+						err!(Request(BadJson(warn!(
+							elapsed=?start.elapsed(),
+							event_id=%target_id,
+							"Failed to parse event fetched from remote: {e}"
+						))))
+					}) {
+						| Ok(auth_events) => auth_events,
+						| Err(e) => {
+							warn!(
+								elapsed=?start.elapsed(),
+								?e,
+								"event {target_id} is malformed (bad auth_events), skipping"
+							);
+							continue;
+						},
+					};
+				let mut have_all_auth = true;
+				for auth_event_id in auth_events {
+					if let Ok(local_pdu) = self.services.timeline.get_pdu(&auth_event_id).await {
+						trace!(elapsed=?start.elapsed(),"Found auth event {auth_event_id} in db");
+						let mut obj = local_pdu.into_canonical_object();
+						obj.remove("event_id");
+						discovered_events.insert(auth_event_id.clone(), obj);
+						continue;
+					}
+					if discovered_events.contains_key(&auth_event_id) {
+						trace!(elapsed=?start.elapsed(),%auth_event_id, "Already found auth event");
+						continue;
+					}
+					debug!(elapsed=?start.elapsed(),"Missing auth event {auth_event_id} for event {target_id}");
+					seen.insert(
+						auth_event_id.clone(),
+						seen.get(&auth_event_id)
+							.copied()
+							.unwrap_or_default()
+							.saturating_add(1),
+					);
+					todo.push_back(auth_event_id);
+					have_all_auth = false;
+				}
+				// Insert this PDU back at the end of the queue so that it will be resolved once
+				// all of its auth events have been fetched.
+				if have_all_auth {
+					debug!(elapsed=?start.elapsed(),%target_id, "Have all auth events");
+					discovered_events.insert(target_id, value);
+				} else {
+					debug_warn!(elapsed=?start.elapsed(),
+						"Fetched {target_id} but missing some auth events, will have to re-fetch."
+					);
+					seen.insert(target_id.clone(), attempts.saturating_add(1));
+					todo.push_back(target_id);
+				}
+			}
+		}
+
+		let refmap: HashMap<OwnedEventId, &CanonicalJsonObject> = discovered_events
+			.iter()
+			.map(|(id, data)| (id.clone(), data))
+			.collect();
+		let seeded_ordered = build_local_dag(&refmap)
+			.await
+			.expect("failed to build local DAG");
+		let mut pdus = HashMap::with_capacity(seeded_ordered.len());
+		for discovered_event_id in seeded_ordered {
+			let pdu_json = discovered_events.remove(&discovered_event_id).unwrap();
+			debug_info!(
+				elapsed=?start.elapsed(),
+				"Handling missing event {discovered_event_id} as outlier"
+			);
+			assert_eq!(pdu_json.get("event_id"), None, "pdu_json had event_id");
 			match Box::pin(self.handle_outlier_pdu(
 				origin,
 				create_event,
-				&next_id,
+				&discovered_event_id,
 				room_id,
-				value.clone(),
-				true,
+				pdu_json,
 			))
 			.await
 			{
-				| Ok((pdu, json)) =>
-					if next_id == *id {
-						trace!("Handled outlier {next_id} (original request)");
-						pdus.push((pdu, Some(json)));
-					},
-				| Err(e) => {
-					warn!("Authentication of event {next_id} failed: {e:?}");
-					back_off(next_id);
+				| Ok((pdu, _)) => {
+					trace!(elapsed=?start.elapsed(), "Persisted {discovered_event_id}");
+					let _ = pdus.insert(discovered_event_id, pdu);
 				},
+				| Err(e) => warn!(
+					elapsed=?start.elapsed(),
+					"Authentication of event {discovered_event_id} failed: {e:?}"
+				),
 			}
 		}
+
+		trace!(
+			elapsed=?start.elapsed(),
+			"Finished fetch_and_handle_missing_events: fetched and handled {} missing PDUs",
+			pdus.len()
+		);
+		pdus.retain(|id, _| events.contains(id)); // Only return state events
+		trace!(elapsed=?start.elapsed(), "Filtered return value down to {} PDUs", pdus.len());
+		pdus
+	}
+
+	/// Similar to `fetch_and_handle_missing_events`, but simply walks the
+	/// prev events tree instead of the auth events tree. Additionally, it does
+	/// not *handle* fetched PDUs in any capacity.
+	#[tracing::instrument(name = "get_missing_prev_events_atomic", skip_all)]
+	pub(super) async fn fetch_prev_events<Pdu>(
+		&self,
+		origin: &ServerName,
+		events: Vec<OwnedEventId>,
+		create_event: &Pdu,
+		room_id: &RoomId,
+	) -> HashMap<OwnedEventId, PduEvent>
+	where
+		Pdu: Event + Send + Sync,
+	{
+		let room_version_rules =
+			&get_room_version_rules(create_event).unwrap_or(RoomVersionRules::V1);
+		let mut candidates = self
+			.services
+			.timeline
+			.candidate_backfill_servers(room_id)
+			.await;
+		candidates.insert(origin.to_owned());
+
+		let mut todo: VecDeque<OwnedEventId> = VecDeque::from(events);
+		let mut discovered_events = HashMap::new();
+		while let Some(next_id) = todo.pop_front() {
+			if discovered_events.len() >= self.services.server.config.max_fetch_prev_events.into()
+			{
+				debug_warn!(
+					"Encountered a gap too large to fill, giving up (fetched {} events)",
+					discovered_events.len()
+				);
+				break;
+			}
+			if discovered_events.contains_key(&next_id) {
+				continue;
+			}
+			let pdu = match self
+				.fetch_event_vias(candidates.iter(), &next_id, room_version_rules)
+				.await
+			{
+				| Ok((_, data)) => data,
+				| Err(e) => {
+					warn!("Failed to fetch prev event {next_id} from any candidate: {e}");
+					continue;
+				},
+			};
+
+			let prev_events = match expect_event_id_array(&pdu, "prev_events").map_err(|e| {
+				err!(Request(BadJson(warn!(
+					event_id=%next_id,
+					"Failed to parse event fetched from remote: {e}"
+				))))
+			}) {
+				| Ok(auth_events) => auth_events,
+				| Err(e) => {
+					warn!(?e, "event {next_id} is malformed (bad prev_events), skipping");
+					continue;
+				},
+			};
+			let missing_prev = prev_events
+				.iter()
+				.stream()
+				.broad_filter_map(|event_id| async {
+					if discovered_events.contains_key(event_id)
+						|| self.services.timeline.pdu_exists(event_id).await
+					{
+						None
+					} else {
+						Some(event_id.to_owned())
+					}
+				})
+				.collect::<Vec<_>>()
+				.await;
+			todo.extend(missing_prev);
+			discovered_events.insert(
+				next_id.clone(),
+				PduEvent::from_id_val(&next_id, pdu).expect("fetched PDU was already validated"),
+			);
+		}
+
+		discovered_events
 	}
-	trace!("Fetched and handled {} outlier pdus", pdus.len());
-	pdus
 }

src/service/rooms/event_handler/fetch_prev.rs

@@ -1,128 +1,150 @@
-use std::{
-	collections::{BTreeMap, HashMap, HashSet, VecDeque},
-	iter::once,
-};
+use std::{collections::HashMap, time::Instant};
 
 use conduwuit::{
-	Event, PduEvent, Result, debug_warn, err, implement,
-	state_res::{self},
-};
-use futures::{FutureExt, future};
-use ruma::{
-	CanonicalJsonValue, EventId, MilliSecondsSinceUnixEpoch, OwnedEventId, RoomId, ServerName,
-	int, uint,
+	Event, PduEvent, debug, debug_info, info, trace,
+	utils::{BoolExt, IterStream, stream::BroadbandExt},
+	warn,
 };
+use futures::StreamExt;
+use ruma::{CanonicalJsonObject, MilliSecondsSinceUnixEpoch, OwnedEventId, RoomId, ServerName};
 
-use super::check_room_id;
+use crate::rooms::event_handler::build_local_dag;
 
-#[implement(super::Service)]
-#[tracing::instrument(
-    level = "debug",
-	skip_all,
-	fields(%origin),
-)]
-#[allow(clippy::type_complexity)]
-pub(super) async fn fetch_prev<'a, Pdu, Events>(
-	&self,
-	origin: &ServerName,
-	create_event: &Pdu,
-	room_id: &RoomId,
-	first_ts_in_room: MilliSecondsSinceUnixEpoch,
-	initial_set: Events,
-) -> Result<(
-	Vec<OwnedEventId>,
-	HashMap<OwnedEventId, (PduEvent, BTreeMap<String, CanonicalJsonValue>)>,
-)>
-where
-	Pdu: Event + Send + Sync,
-	Events: Iterator<Item = &'a EventId> + Clone + Send,
-{
-	let num_ids = initial_set.clone().count();
-	let mut eventid_info = HashMap::new();
-	let mut graph: HashMap<OwnedEventId, _> = HashMap::with_capacity(num_ids);
-	let mut todo_outlier_stack: VecDeque<OwnedEventId> =
-		initial_set.map(ToOwned::to_owned).collect();
-
-	let mut amount = 0;
-
-	while let Some(prev_event_id) = todo_outlier_stack.pop_front() {
-		self.services.server.check_running()?;
-
-		match self
-			.fetch_and_handle_outliers(
-				origin,
-				once(prev_event_id.as_ref()),
-				create_event,
-				room_id,
-			)
-			.boxed()
-			.await
-			.pop()
-		{
-			| Some((pdu, mut json_opt)) => {
-				check_room_id(room_id, &pdu)?;
-
-				let limit = self.services.server.config.max_fetch_prev_events;
-				if amount > limit {
-					debug_warn!("Max prev event limit reached! Limit: {limit}");
-					graph.insert(prev_event_id.clone(), HashSet::new());
-					continue;
-				}
-
-				if json_opt.is_none() {
-					json_opt = self
-						.services
-						.outlier
-						.get_outlier_pdu_json(&prev_event_id)
-						.await
-						.ok();
-				}
-
-				if let Some(json) = json_opt {
-					if pdu.origin_server_ts() > first_ts_in_room {
-						amount = amount.saturating_add(1);
-						for prev_prev in pdu.prev_events() {
-							if !graph.contains_key(prev_prev) {
-								todo_outlier_stack.push_back(prev_prev.to_owned());
-							}
-						}
-
-						graph.insert(
-							prev_event_id.clone(),
-							pdu.prev_events().map(ToOwned::to_owned).collect(),
-						);
-					} else {
-						// Time based check failed
-						graph.insert(prev_event_id.clone(), HashSet::new());
-					}
-
-					eventid_info.insert(prev_event_id.clone(), (pdu, json));
-				} else {
-					// Get json failed, so this was not fetched over federation
-					graph.insert(prev_event_id.clone(), HashSet::new());
-				}
-			},
-			| _ => {
-				// Fetch and handle failed
-				graph.insert(prev_event_id.clone(), HashSet::new());
-			},
+impl super::Service {
+	/// Fetches any missing prev_events for this event and persists them before
+	/// returning.
+	pub(super) async fn fetch_prevs(
+		&self,
+		room_id: &RoomId,
+		create_event: &PduEvent,
+		incoming_pdu: &PduEvent,
+		origin: &ServerName,
+		first_ts_in_room: MilliSecondsSinceUnixEpoch,
+	) -> conduwuit::Result<()> {
+		let start = Instant::now();
+		let mut missing = incoming_pdu
+			.prev_events()
+			.stream()
+			.broad_filter_map(|event_id| async move {
+				self.services
+					.timeline
+					.get_non_outlier_pdu_json(event_id)
+					.await
+					.is_ok()
+					.or(|| event_id.to_owned())
+			})
+			.collect::<Vec<_>>()
+			.await;
+		if missing.is_empty() {
+			debug!(elapsed=?start.elapsed(), event_id=%incoming_pdu.event_id(), "No missing prev events.");
+			return Ok(());
 		}
+		debug!(elapsed=?start.elapsed(), %room_id, event_id=%incoming_pdu.event_id(), ?missing, "Fetching previous events");
+		let tail = self
+			.services
+			.state
+			.get_forward_extremities(room_id)
+			.collect::<Vec<_>>()
+			.await;
+
+		let mut gapfilled = self
+			.get_missing_events(
+				room_id,
+				incoming_pdu,
+				tail,
+				origin,
+				self.services
+					.metadata
+					.get_mindepth(room_id)
+					.await
+					.saturating_sub(
+						u8::try_from(incoming_pdu.prev_events.len())
+							.unwrap()
+							.saturating_mul(2)
+							.into(),
+					),
+			)
+			.await?;
+		debug_info!(elapsed=?start.elapsed(), "Fetched {} missing events", gapfilled.len());
+		missing.retain(|eid| !gapfilled.contains_key(eid));
+		if !missing.is_empty() {
+			warn!(elapsed=?start.elapsed(), "Still missing {} events, falling back to atomic fetch.", missing.len());
+			gapfilled.extend(
+				self.fetch_prev_events(origin, missing, create_event, room_id)
+					.await,
+			);
+		}
+
+		// Persist all fetched events
+		let mapped = gapfilled
+			.iter()
+			.map(|(eid, evt)| {
+				let mut obj = evt.to_canonical_object();
+				obj.remove("event_id"); // event_id is inserted by backfill_missing_events
+				(eid.clone(), obj)
+			})
+			.collect::<HashMap<_, _>>();
+
+		let to_persist = if mapped.len() <= 1 {
+			mapped.keys().map(ToOwned::to_owned).collect()
+		} else {
+			let refmap: HashMap<OwnedEventId, &CanonicalJsonObject> =
+				mapped.iter().map(|(id, data)| (id.clone(), data)).collect();
+			build_local_dag(&refmap).await?
+		};
+
+		let job_start = Instant::now();
+		trace!("Starting to persist {} prev events", to_persist.len());
+		for (i, event_id) in to_persist.iter().enumerate() {
+			info!(
+				elapsed=?start.elapsed(),
+				"Persisting fetched prev event: {event_id} ({}/{})",
+				i.saturating_add(1),
+				to_persist.len(),
+			);
+			let obj = mapped.get(event_id).cloned().unwrap();
+			let persist_start = Instant::now();
+			match self
+				.handle_outlier_pdu(origin, create_event, event_id, room_id, obj)
+				.await
+			{
+				| Ok((pdu, val)) if pdu.origin_server_ts() >= first_ts_in_room => {
+					self.upgrade_outlier_to_timeline_pdu(pdu, val, create_event, origin, room_id)
+						.await
+						.inspect_err(|e| {
+							warn!(
+								total_elapsed=?start.elapsed(),
+								job_elapsed=?job_start.elapsed(),
+								task_elapsed=?persist_start.elapsed(),
+								"Failed to upgrade prev event {event_id}: {e}",
+							);
+						})
+						.inspect(|_| {
+							info!(
+								total_elapsed=?start.elapsed(),
+								job_elapsed=?job_start.elapsed(),
+								task_elapsed=?persist_start.elapsed(),
+								"Upgraded prev event {event_id}",
+							);
+						})
+						.ok();
+				},
+				| Err(e) => warn!(
+					total_elapsed=?start.elapsed(),
+					job_elapsed=?job_start.elapsed(),
+					task_elapsed=?persist_start.elapsed(),
+					"Failed to persist prev event {event_id}: {e}",
+				),
+				| _ => {},
+			}
+		}
+
+		// NOTE because i keep forgetting: the caller persists incoming_pdu.
+		// we only care about its prev events
+		trace!(
+			total_elapsed=?start.elapsed(),
+			persist_elapsed=?job_start.elapsed(),
+		);
+		Ok(())
 	}
-
-	let event_fetch = |event_id| {
-		let origin_server_ts = eventid_info
-			.get(&event_id)
-			.map_or_else(|| uint!(0), |info| info.0.origin_server_ts().get());
-
-		// This return value is the key used for sorting events,
-		// events are then sorted by power level, time,
-		// and lexically by event_id.
-		future::ok((int!(0), MilliSecondsSinceUnixEpoch(origin_server_ts)))
-	};
-
-	let sorted = state_res::lexicographical_topological_sort(&graph, &event_fetch)
-		.await
-		.map_err(|e| err!(Database(error!("Error sorting prev events: {e}"))))?;
-
-	Ok((sorted, eventid_info))
 }

src/service/rooms/event_handler/fetch_state.rs

@@ -1,86 +1,392 @@
-use std::collections::{HashMap, hash_map};
-
-use conduwuit::{Err, Event, Result, debug, debug_warn, err, implement};
-use futures::FutureExt;
-use ruma::{
-	EventId, OwnedEventId, RoomId, ServerName, api::federation::event::get_room_state_ids,
-	events::StateEventType,
+use std::{
+	cmp::max,
+	collections::{HashMap, HashSet, hash_map},
+	hash::{BuildHasherDefault, DefaultHasher},
+	time::{Duration, Instant},
 };
 
-use crate::rooms::short::ShortStateKey;
+use conduwuit::{
+	Err, Event, PduEvent, Result, debug, debug_warn, err, info, trace,
+	utils::{BoolExt, IterStream},
+	warn,
+};
+use futures::{StreamExt, TryFutureExt, future::select_ok};
+use ruma::{
+	EventId, OwnedEventId, OwnedRoomId, RoomId, ServerName,
+	api::federation::event::{get_room_state, get_room_state_ids},
+};
 
-/// Call /state_ids to find out what the state at this pdu is. We trust the
-/// server's response to some extend (sic), but we still do a lot of checks
-/// on the events
-#[implement(super::Service)]
-#[tracing::instrument(
-	level = "debug",
-	skip_all,
-	fields(%origin),
-)]
-pub(super) async fn fetch_state<Pdu>(
-	&self,
-	origin: &ServerName,
-	create_event: &Pdu,
-	room_id: &RoomId,
-	event_id: &EventId,
-) -> Result<Option<HashMap<u64, OwnedEventId>>>
-where
-	Pdu: Event + Send + Sync,
-{
-	let res = self
-		.services
-		.sending
-		.send_federation_request(
-			origin,
-			get_room_state_ids::v1::Request::new(event_id.to_owned(), room_id.to_owned()),
-		)
-		.await
-		.inspect_err(|e| debug_warn!("Fetching state for event failed: {e}"))?;
+use crate::{conduwuit::utils::stream::BroadbandExt, rooms::short::ShortStateKey};
 
-	debug!("Fetching state events");
-	let state_ids = res.pdu_ids.iter().map(AsRef::as_ref);
-	let state_vec = self
-		.fetch_and_handle_outliers(origin, state_ids, create_event, room_id)
-		.boxed()
-		.await;
-
-	let mut state: HashMap<ShortStateKey, OwnedEventId> = HashMap::with_capacity(state_vec.len());
-	for (pdu, _) in state_vec {
-		let state_key = pdu
-			.state_key()
-			.ok_or_else(|| err!(Database("Found non-state pdu in state events.")))?;
-
-		let shortstatekey = self
+impl super::Service {
+	/// Asks a remote server what the state at this event is.
+	/// It first attempts to call `GET /_matrix/federation/v1/state_ids` (fast).
+	/// If any events are missing, they are fetched from the remote, and
+	/// persisted as outliers, before being returned back to this function. If
+	/// we are missing a lot of events locally (>=50), this function falls back
+	/// to requesting the full state in PDU format from the remote (`GET
+	/// /_matrix/federation/v1/state, very slow in large rooms), and persists
+	/// them directly.
+	#[tracing::instrument(skip_all)]
+	pub(super) async fn fetch_state(
+		&self,
+		origin: &ServerName,
+		create_event: &PduEvent,
+		room_id: &RoomId,
+		event_id: &EventId,
+	) -> Result<HashMap<u64, OwnedEventId>> {
+		let start = Instant::now();
+		trace!(%origin, "Asking remote for state_ids");
+		let res: get_room_state_ids::v1::Response = match self
 			.services
-			.short
-			.get_or_create_shortstatekey(&pdu.kind().to_string().into(), state_key)
+			.sending
+			.send_federation_request(
+				origin,
+				get_room_state_ids::v1::Request::new(event_id.to_owned(), room_id.to_owned()),
+			)
+			.await
+			.inspect_err(
+				|e| debug_warn!(elapsed=?start.elapsed(), "Fetching state for event failed: {e}"),
+			) {
+			| Ok(resp) => Ok(resp),
+			| Err(e) =>
+				if e.is_not_found() {
+					self.fetch_state_ids_from_backfill_servers(
+						event_id.to_owned(),
+						room_id.to_owned(),
+					)
+					.await
+				} else {
+					Err(e)
+				},
+		}?;
+
+		debug!(elapsed=?start.elapsed(), events = res.pdu_ids.len(), "Fetching state events");
+		let mut state_events: HashMap<OwnedEventId, PduEvent> =
+			HashMap::with_capacity(res.pdu_ids.len());
+		let to_fetch: Vec<OwnedEventId> = res
+			.pdu_ids
+			.clone()
+			.into_iter()
+			.stream()
+			.broad_filter_map(|event_id| async move {
+				self.services
+					.timeline
+					.pdu_exists(&event_id)
+					.await
+					.or_some(event_id)
+			})
+			.collect()
 			.await;
+		if to_fetch.is_empty() {
+			debug!(elapsed=?start.elapsed(), "All required state events are already known.");
+			state_events = res
+				.pdu_ids
+				.iter()
+				.stream()
+				.broad_filter_map(|event_id| async move {
+					Some((
+						event_id.clone(),
+						self.services
+							.timeline
+							.get_pdu(event_id)
+							.await
+							.expect("Event disappeared between filtering and fetching"),
+					))
+				})
+				.collect()
+				.await;
+			assert_eq!(
+				state_events.len(),
+				res.pdu_ids.len(),
+				"Failed to load all required state events despite allegedly knowing all of them \
+				 already",
+			);
+		} else {
+			let total_count = res.pdu_ids.len();
+			let missing_count = to_fetch.len();
+			let missing_threshold = max(50, total_count >> 2);
+			if missing_count >= missing_threshold {
+				// If there's more than 50 events to fetch, or we're missing 25% or more of the
+				// state, we would need to make a lot of atomic requests, so we'll just try
+				// to fetch the full state from the remote instead.
+				// Since this endpoint might fail in huge rooms, we fall back to atomic fetch
+				// anyway.
+				warn!(
+					elapsed=?start.elapsed(),
+					%missing_count,
+					%total_count,
+					%missing_threshold,
+					"Fetching full state from remote server for event"
+				);
+				let state_response = tokio::time::timeout(
+					Duration::from_secs(30),
+					self.fetch_full_state(origin, create_event, room_id, event_id),
+				)
+				.await;
+				info!(
+					elapsed=?start.elapsed(),
+					%missing_count,
+					%total_count,
+					%missing_threshold,
+					"Fetched full state from remote server for event"
+				);
+				let fetched_state = match state_response {
+					| Ok(Ok(state)) => {
+						// Filter to ensure we only use the PDUs we were expecting, preventing
+						// arbitrary state injection.
+						// Atomic fetch does not have this problem as each PDU is evaluated
+						// individually.
+						let expected: &HashSet<OwnedEventId, BuildHasherDefault<DefaultHasher>> =
+							&HashSet::from_iter(res.pdu_ids.clone());
+						state
+							.into_iter()
+							.stream()
+							.broad_filter_map(|(event_id, pdu)| async move {
+								expected.contains(&event_id).then_some((event_id, pdu))
+							})
+							.collect()
+							.await
+					},
+					| Ok(Err(e)) => {
+						warn!(
+							elapsed=?start.elapsed(),
+							error=?e,
+							%origin,
+							"Failed to fetch full state from remote, falling back to atomic fetch"
+						);
+						self.fetch_and_handle_auth_events(
+							origin,
+							res.pdu_ids.clone(),
+							create_event,
+							room_id,
+						)
+						.await
+					},
+					| Err(e) => {
+						warn!(
+							elapsed=?start.elapsed(),
+							error=?e,
+							%origin,
+							"Remote did not return room state in an acceptable timeframe, falling back to atomic fetch"
+						);
+						self.fetch_and_handle_auth_events(
+							origin,
+							res.pdu_ids.clone(),
+							create_event,
+							room_id,
+						)
+						.await
+					},
+				};
 
-		match state.entry(shortstatekey) {
-			| hash_map::Entry::Vacant(v) => {
-				v.insert(pdu.event_id().to_owned());
-			},
-			| hash_map::Entry::Occupied(_) => {
-				return Err!(Database(
-					"State event's type and state_key combination exists multiple times: {}, {}",
-					pdu.kind(),
-					state_key
-				));
-			},
+				assert!(
+					!fetched_state.is_empty(),
+					"fetch_full_state or fetch_and_handle_missing_events returned empty state \
+					 map"
+				);
+				state_events.extend(fetched_state);
+			} else {
+				state_events = res
+					.pdu_ids
+					.iter()
+					.stream()
+					.broad_filter_map(|event_id| async move {
+						self.services
+							.timeline
+							.get_pdu(event_id)
+							.await
+							.map(|p| (event_id.to_owned(), p))
+							.ok()
+					})
+					.collect()
+					.await;
+				assert!(
+					!state_events.is_empty(),
+					"Only missing {} events but read-ahead state vec was empty",
+					to_fetch.len()
+				);
+				debug!(
+					elapsed=?start.elapsed(),
+					to_fetch = to_fetch.len(),
+					"Fetching missing events for state from remote"
+				);
+				let fetched_state = self
+					.fetch_and_handle_auth_events(origin, to_fetch, create_event, room_id)
+					.await;
+				state_events.extend(fetched_state);
+			}
 		}
+		if state_events.is_empty() {
+			return Ok(HashMap::new());
+		}
+
+		let mut state: HashMap<ShortStateKey, OwnedEventId> =
+			HashMap::with_capacity(state_events.len());
+		debug!(elapsed=?start.elapsed(), events = state_events.len(), "Processing state events");
+		for (event_id, pdu) in state_events {
+			let state_key = pdu.state_key().ok_or_else(|| {
+				err!(Request(BadJson("Found non-state pdu in state events: {event_id}")))
+			})?;
+
+			let shortstatekey = self
+				.services
+				.short
+				.get_or_create_shortstatekey(&pdu.kind().to_string().into(), state_key)
+				.await;
+
+			match state.entry(shortstatekey) {
+				| hash_map::Entry::Vacant(v) => {
+					v.insert(pdu.event_id().to_owned());
+				},
+				| hash_map::Entry::Occupied(existing) => {
+					return Err!(Request(Forbidden(
+						"State event's type and state_key combination exists multiple times \
+						 ({event_id} + {}): ({}, \"{}\")",
+						existing.get(),
+						pdu.kind(),
+						state_key,
+					)));
+				},
+			}
+		}
+		trace!(elapsed=?start.elapsed(), "fetch_state finished");
+		Ok(state)
 	}
 
-	// The original create event must still be in the state
-	let create_shortstatekey = self
-		.services
-		.short
-		.get_shortstatekey(&StateEventType::RoomCreate, "")
-		.await?;
-
-	if state.get(&create_shortstatekey).map(AsRef::as_ref) != Some(create_event.event_id()) {
-		return Err!(Database("Incoming event refers to wrong create event."));
+	async fn fetch_state_ids_from_backfill_servers(
+		&self,
+		event_id: OwnedEventId,
+		room_id: OwnedRoomId,
+	) -> Result<get_room_state_ids::v1::Response> {
+		let candidates = self
+			.services
+			.timeline
+			.candidate_backfill_servers(&room_id)
+			.await;
+		if candidates.is_empty() {
+			return Err!(Request(NotFound(
+				"Cannot ask any other servers for the state at this event"
+			)));
+		}
+		debug!(%room_id, ?candidates, "Asking backfill servers for state_ids");
+		let futures = candidates.iter().map(|server_name| {
+			Box::pin(
+				self.services
+					.sending
+					.send_federation_request(
+						server_name,
+						get_room_state_ids::v1::Request::new(event_id.clone(), room_id.clone()),
+					)
+					.inspect_err(|e| {
+						debug_warn!("Fallback fetching state for event failed: {e}");
+					}),
+			)
+		});
+		Ok(select_ok(futures).await?.0)
 	}
 
-	Ok(Some(state))
+	/// Fetches the full state via `GET /_matrix/federation/v1/state` from a
+	/// remote server, and persists all the incoming auth chain events and
+	/// state events as outliers, for use later.
+	///
+	/// Any events that cannot be persisted are dropped with a warning.
+	pub(super) async fn fetch_full_state(
+		&self,
+		origin: &ServerName,
+		create_event: &PduEvent,
+		room_id: &RoomId,
+		event_id: &EventId,
+	) -> Result<HashMap<OwnedEventId, PduEvent>> {
+		let start = Instant::now();
+		trace!("Fetching full state from remote server");
+		let res: get_room_state::v1::Response = self
+			.services
+			.sending
+			.send_federation_request(
+				origin,
+				get_room_state::v1::Request::new(event_id.to_owned(), room_id.to_owned()),
+			)
+			.await
+			.inspect_err(|e| debug_warn!("Fetching state for event failed: {e}"))?;
+		debug!(elapsed=?start.elapsed(), count = res.auth_chain.len(), "Handling incoming auth chain...");
+		res.auth_chain
+			.iter()
+			.stream()
+			.broad_filter_map(|raw_event_json| async {
+				if let Some(parsed) = self.parse_incoming_pdu(raw_event_json).await.ok()
+					&& parsed.0 == room_id
+				{
+					Some(parsed)
+				} else {
+					None
+				}
+			})
+			.for_each_concurrent(
+				None,
+				|(incoming_room_id, incoming_event_id, incoming_event_json)| async move {
+					self.handle_outlier_pdu(
+						origin,
+						create_event,
+						&incoming_event_id,
+						&incoming_room_id,
+						incoming_event_json,
+					)
+					.await
+					.inspect_err(|e| {
+						warn!(
+							%incoming_room_id,
+							%incoming_event_id,
+							?e,
+							"Failed to handle auth chain event from state fetch"
+						);
+					})
+					.ok();
+				},
+			)
+			.await;
+		debug!(elapsed=?start.elapsed(), count = res.pdus.len(), "Handling incoming state PDUs...");
+		let r = res
+			.pdus
+			.iter()
+			.stream()
+			.broad_filter_map(|raw_event_json| async {
+				if let Some(parsed) = self.parse_incoming_pdu(raw_event_json).await.ok()
+					&& parsed.0 == room_id
+				{
+					Some(parsed)
+				} else {
+					None
+				}
+			})
+			.broad_filter_map(
+				|(incoming_room_id, incoming_event_id, incoming_event_json)| async move {
+					self.handle_outlier_pdu(
+						origin,
+						create_event,
+						&incoming_event_id,
+						&incoming_room_id,
+						incoming_event_json,
+					)
+					.await
+					.inspect_err(|e| {
+						warn!(
+							elapsed=?start.elapsed(),
+							%incoming_room_id,
+							%incoming_event_id,
+							?e,
+							"Failed to handle state event from state fetch"
+						);
+					})
+					.ok()
+				},
+			)
+			.fold(HashMap::new(), |mut acc, (event, _)| async move {
+				acc.insert(event.event_id().to_owned(), event);
+				acc
+			})
+			.await;
+		trace!(elapsed=?start.elapsed(), "fetch_full_state finished");
+		Ok(r)
+	}
 }

src/service/rooms/event_handler/handle_incoming_pdu.rs

@@ -1,14 +1,14 @@
 use std::{
-	collections::{BTreeMap, hash_map},
-	time::Instant,
+	collections::BTreeMap,
+	time::{Duration, Instant},
 };
 
 use conduwuit::{
-	Err, Event, PduEvent, Result, debug::INFO_SPAN_LEVEL, debug_error, debug_info, defer, err,
-	implement, info, trace, utils::stream::IterStream, warn,
+	Err, Event, PduEvent, Result, debug, debug_error, debug_info, debug_warn, defer, err, error,
+	implement, info, matrix::PartialPdu, result::DebugInspect, trace, warn,
 };
 use futures::{
-	FutureExt, TryFutureExt, TryStreamExt,
+	FutureExt, StreamExt,
 	future::{OptionFuture, try_join4},
 };
 use ruma::{
@@ -18,7 +18,6 @@
 		room::member::{MembershipState, RoomMemberEventContent},
 	},
 };
-use tracing::debug;
 
 use crate::rooms::timeline::{RawPduId, pdu_fits};
 
@@ -111,7 +110,6 @@ async fn should_rescind_invite(
 #[implement(super::Service)]
 #[tracing::instrument(
 	name = "pdu",
-	level = INFO_SPAN_LEVEL,
 	skip_all,
 	fields(%room_id, %event_id),
 )]
@@ -151,7 +149,7 @@ pub async fn handle_incoming_pdu<'a>(
 		.and_then(|v| v.as_str())
 		.ok_or_else(|| err!("No sender in object"))
 		.and_then(|v| Ok(UserId::parse(v)?))
-		.map_err(|e| err!(Request(InvalidParam("PDU does not have a valid sender key: {e}"))))?;
+		.map_err(|e| err!(Request(BadJson("PDU does not have a valid sender key: {e}"))))?;
 
 	let sender_acl_check: OptionFuture<_> = sender
 		.server_name()
@@ -224,75 +222,107 @@ pub async fn handle_incoming_pdu<'a>(
 		self.federation_handletime
 			.write()
 			.remove(room_id);
-	}};
+	}}
 
 	let (incoming_pdu, val) = self
-		.handle_outlier_pdu(origin, create_event, event_id, room_id, value, false)
-		.await?;
+		.handle_outlier_pdu(origin, create_event, event_id, room_id, value)
+		.await
+		.inspect_err(|e| error!("Failed to handle outlier PDU: {e:?}"))?;
 
 	// 8. if not timeline event: stop
 	if !is_timeline_event {
 		return Ok(None);
 	}
 
-	// Skip old events
+	// Skip events sent before we joined (they need to be persisted as backfilled
+	// events, not timeline events, which is handled elsewhere).
 	let first_ts_in_room = self
 		.services
 		.timeline
 		.first_pdu_in_room(room_id)
 		.await?
 		.origin_server_ts();
+	if incoming_pdu.origin_server_ts() < first_ts_in_room {
+		return Ok(None);
+	}
 
 	// 9. Fetch any missing prev events doing all checks listed here starting at 1.
 	//    These are timeline events
-	let (sorted_prev_events, mut eventid_info) = self
-		.fetch_prev(origin, create_event, room_id, first_ts_in_room, incoming_pdu.prev_events())
-		.await?;
 
-	debug!(
-		events = ?sorted_prev_events,
-		"Handling previous events"
-	);
-
-	sorted_prev_events
-		.iter()
-		.try_stream()
-		.map_ok(AsRef::as_ref)
-		.try_for_each(|prev_id| {
-			self.handle_prev_pdu(
-				origin,
-				event_id,
-				room_id,
-				eventid_info.remove(prev_id),
-				create_event,
-				first_ts_in_room,
-				prev_id,
-			)
-			.inspect_err(move |e| {
-				warn!("Prev {prev_id} failed: {e}");
-				match self
-					.services
-					.globals
-					.bad_event_ratelimiter
-					.write()
-					.entry(prev_id.into())
-				{
-					| hash_map::Entry::Vacant(e) => {
-						e.insert((Instant::now(), 1));
-					},
-					| hash_map::Entry::Occupied(mut e) => {
-						let tries = e.get().1.saturating_add(1);
-						*e.get_mut() = (Instant::now(), tries);
-					},
-				}
-			})
-			.map(|_| self.services.server.check_running())
-		})
-		.boxed()
-		.await?;
+	debug!("Fetching and persisting any missing prev events");
+	self.fetch_prevs(room_id, create_event, &incoming_pdu, origin, first_ts_in_room)
+		.await
+		.debug_inspect_err(|e| {
+			error!("Failed to fetch and persist incoming event's prev_events: {e:?}");
+		})?;
 
 	// Done with prev events, now handling the incoming event
-	self.upgrade_outlier_to_timeline_pdu(incoming_pdu, val, create_event, origin, room_id)
-		.boxed()
-		.await
+	let pdu_id = self
+		.upgrade_outlier_to_timeline_pdu(incoming_pdu, val, create_event, origin, room_id)
+		.await?;
+
+	let extremities_count = self
+		.services
+		.state
+		.get_forward_extremities(room_id)
+		.count()
+		.await;
+
+	if extremities_count >= self.services.server.config.dummy_event_threshold.into() {
+		self.squash_extremities(room_id, extremities_count).await;
+	}
+
+	Ok(pdu_id)
+}
+
+#[implement(super::Service)]
+async fn squash_extremities(&self, room_id: &RoomId, count: usize) {
+	let last_squash = {
+		let squash_timings = self.last_extremity_squash.read();
+		squash_timings.get(room_id).copied()
+	};
+	if last_squash.is_some_and(|s| s.elapsed() < Duration::from_mins(1)) {
+		// Avoid sending more than one squash per minute to avoid flooding rooms.
+		return;
+	}
+	debug_warn!(
+		%count,
+		threshold=%self.services.server.config.dummy_event_threshold,
+		"Attempting to squash extremities after upgrading pdu"
+	);
+	// Try to send a dummy event to squash extremities. See issue #1844
+	let power_levels = self
+		.services
+		.state_accessor
+		.get_room_power_levels(room_id)
+		.await;
+	let mut local_users = self.services.state_cache.local_users_in_room(room_id);
+	while let Some(user_id) = local_users.next().await {
+		if !power_levels.user_can_send_message(&user_id, "org.matrix.dummy_event".into()) {
+			trace!(%user_id, "user does not have power level to send dummy event, skipping");
+			continue;
+		}
+		let state_lock = self.services.state.mutex.lock(room_id).await;
+		if self
+			.services
+			.timeline
+			.build_and_append_pdu(
+				PartialPdu {
+					event_type: "org.matrix.dummy_event".into(),
+					..PartialPdu::default()
+				},
+				&user_id,
+				Some(room_id),
+				&state_lock,
+			)
+			.await
+			.inspect(|_| debug!(sender=%user_id, "Successfully sent a dummy event"))
+			.inspect_err(|e| debug!(sender=%user_id, ?e, "Failed to send a dummy event via user"))
+			.is_ok()
+		{
+			break;
+		}
+	}
+	let mut squash_timings = self.last_extremity_squash.write();
+	squash_timings.insert(room_id.to_owned(), Instant::now());
 }

src/service/rooms/event_handler/handle_outlier_pdu.rs

@@ -1,12 +1,13 @@
 use std::collections::{BTreeMap, HashMap, hash_map};
 
 use conduwuit::{
-	Err, Event, PduEvent, Result, debug, debug_info, debug_warn, err, implement, state_res,
+	Err, Event, PduEvent, Result, debug, debug_info, debug_warn, err, implement, info, state_res,
 	trace, warn,
 };
 use futures::future::ready;
 use ruma::{
 	CanonicalJsonObject, CanonicalJsonValue, EventId, OwnedEventId, RoomId, ServerName,
+	api::federation::authorization::get_event_authorization, canonical_json::redact,
 	events::StateEventType,
 };
 
@@ -15,6 +16,7 @@
 
 #[implement(super::Service)]
 #[allow(clippy::too_many_arguments)]
+#[tracing::instrument(name="handle_outlier", skip_all, fields(%event_id))]
 pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 	&self,
 	origin: &'a ServerName,
@@ -22,7 +24,6 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 	event_id: &'a EventId,
 	room_id: &'a RoomId,
 	mut value: CanonicalJsonObject,
-	auth_events_known: bool,
 ) -> Result<(PduEvent, BTreeMap<String, CanonicalJsonValue>)>
 where
 	Pdu: Event + Send + Sync,
@@ -46,27 +47,38 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 		.verify_event(&value, &room_version_rules)
 		.await
 	{
-		| Ok(ruma::signatures::Verified::All) => value,
+		| Ok(ruma::signatures::Verified::All) => {
+			if let Ok(pdu_event) = self.services.timeline.get_pdu(event_id).await {
+				debug!(
+					"Already have event {event_id} as an outlier or timeline event, not \
+					 re-processing"
+				);
+				value.insert(
+					"event_id".to_owned(),
+					CanonicalJsonValue::String(event_id.as_str().to_owned()),
+				);
+				check_room_id(room_id, &pdu_event)?;
+				return Ok((pdu_event, value));
+			}
+			value
+		},
 		| Ok(ruma::signatures::Verified::Signatures) => {
-			// Redact
-			debug_info!("Calculated hash does not match (redaction): {event_id}");
-			let Ok(obj) =
-				ruma::canonical_json::redact(value, &room_version_rules.redaction, None)
-			else {
-				return Err!(Request(InvalidParam("Redaction failed")));
-			};
-
-			// Skip the PDU if it is redacted and we already have it as an outlier event
-			if self.services.timeline.pdu_exists(event_id).await {
-				return Err!(Request(InvalidParam(
-					"Event was redacted and we already knew about it"
-				)));
+			if let Ok(pdu_event) = self.services.timeline.get_pdu(event_id).await {
+				debug!(
+					"Received a redacted copy of {event_id}, but we already knew about it. \
+					 Re-using known content instead."
+				);
+				check_room_id(room_id, &pdu_event)?;
+				let obj = pdu_event.to_canonical_object();
+				return Ok((pdu_event, obj));
 			}
 
-			obj
+			debug_info!("Calculated hash does not match (redaction): {event_id}");
+			redact(value, &room_version_rules.redaction, None)
+				.map_err(|e| err!(Request(BadJson("Failed to redact {event_id}: {e}"))))?
 		},
 		| Err(e) => {
-			return Err!(Request(InvalidParam(debug_error!(
+			return Err!(Request(Forbidden(debug_error!(
 				"Signature verification failed for {event_id}: {e}"
 			))));
 		},
@@ -87,65 +99,78 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 	// Fetch all auth events
 	let mut auth_events: HashMap<OwnedEventId, PduEvent> = HashMap::new();
 
-	for aid in pdu_event.auth_events() {
-		if self.services.pdu_metadata.is_event_rejected(aid).await {
+	for auth_event_id in pdu_event.auth_events() {
+		if self
+			.services
+			.pdu_metadata
+			.is_event_rejected(auth_event_id)
+			.await
+		{
 			debug_warn!(
-				"Rejecting incoming event {} which depends on rejected auth event {aid}",
+				"Rejecting incoming event {} which depends on rejected auth event \
+				 {auth_event_id}",
 				event_id,
 			);
 			self.services.pdu_metadata.mark_event_rejected(event_id);
-			return Err!(Request(InvalidParam("Event has rejected auth event: {aid}")));
+			return Err!(Request(Forbidden("Event has rejected auth event: {auth_event_id}")));
 		}
 
-		if let Ok(auth_event) = self.services.timeline.get_pdu(aid).await {
+		if let Ok(auth_event) = self.services.timeline.get_pdu(auth_event_id).await {
 			check_room_id(room_id, &auth_event)?;
-			trace!("Found auth event {aid} for outlier event {event_id} locally");
-			auth_events.insert(aid.to_owned(), auth_event);
+			trace!("Found auth event {auth_event_id} for outlier event {event_id} locally");
+			auth_events.insert(auth_event_id.to_owned(), auth_event);
 		} else {
-			debug_warn!("Could not find auth event {aid} for outlier event {event_id} locally");
+			debug_warn!(
+				"Could not find auth event {auth_event_id} for outlier event {event_id} locally"
+			);
 		}
 	}
 
 	// Fetch any missing ones & reject invalid ones
-	let missing_auth_events = if auth_events_known {
-		pdu_event
-			.auth_events()
-			.filter(|id| !auth_events.contains_key(*id))
-			.collect::<Vec<_>>()
-	} else {
-		pdu_event.auth_events().collect::<Vec<_>>()
-	};
-	if !missing_auth_events.is_empty() || !auth_events_known {
-		debug_info!(
-			"Fetching {} missing auth events for outlier event {event_id}",
-			missing_auth_events.len()
-		);
-		for (pdu, _) in self
-			.fetch_and_handle_outliers(
+	if auth_events.len() != pdu_event.auth_events().count() {
+		info!("Missing some auth events, asking remote for auth chain");
+		let response: get_event_authorization::v1::Response = self
+			.services
+			.sending
+			.send_federation_request(
 				origin,
-				missing_auth_events.iter().copied(),
-				create_event,
-				room_id,
+				get_event_authorization::v1::Request::new(
+					room_id.to_owned(),
+					event_id.to_owned(),
+				),
 			)
 			.await
-		{
-			auth_events.insert(pdu.event_id().to_owned(), pdu);
+			.map_err(|e| {
+				err!(Request(Forbidden(
+					"Remote server is not divulging incoming event's auth chain: {e}"
+				)))
+			})?;
+		let mut auth_chain_map = HashMap::with_capacity(response.auth_chain.len());
+		for auth_pdu_json in response.auth_chain {
+			let (auth_event_room_id, auth_event_id, auth_pdu_json) =
+				self.parse_incoming_pdu(&auth_pdu_json).await?;
+			if auth_event_room_id != room_id {
+				return Err!(Request(Forbidden(
+					"Auth event {auth_event_id} is in {auth_event_room_id}, not {room_id}."
+				)));
+			}
+			let auth_pdu = PduEvent::from_id_val(&auth_event_id, auth_pdu_json)
+				.map_err(|e| err!(Request(BadJson("Invalid PDU {auth_event_id}: {e}"))))?;
+			auth_chain_map.insert(auth_event_id, auth_pdu);
+		}
+		for auth_event_id in pdu_event.auth_events() {
+			if auth_events.contains_key(auth_event_id) {
+				continue;
+			}
+			if let Some(auth_event) = auth_chain_map.get(auth_event_id) {
+				auth_events.insert(auth_event_id.to_owned(), auth_event.clone());
+			} else {
+				return Err!(Request(Forbidden(
+					"Remote server is not divulging incoming event's auth events (missing: \
+					 {auth_event_id})"
+				)));
+			}
 		}
-	} else {
-		debug!("No missing auth events for outlier event {event_id}");
-	}
-	// reject if we are still missing some
-	let still_missing = pdu_event
-		.auth_events()
-		.filter(|id| !auth_events.contains_key(*id))
-		.collect::<Vec<_>>();
-	if !still_missing.is_empty() {
-		// Don't reject: this could be a temporary condition
-		// TODO: use get_missing_events?
-		return Err!(Request(InvalidParam(
-			"Could not fetch all auth events for outlier event {event_id}, still missing: \
-			 {still_missing:?}"
-		)));
 	}
 
 	// 6. Reject "due to auth events" if the event doesn't pass auth based on the
@@ -176,7 +201,7 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 					.outlier
 					.add_pdu_outlier(pdu_event.event_id(), &incoming_pdu);
 				self.services.pdu_metadata.mark_event_rejected(event_id);
-				return Err!(Request(InvalidParam(
+				return Err!(Request(Forbidden(
 					"Auth event's type and state_key combination exists multiple times: {}, {}",
 					auth_event.kind,
 					auth_event.state_key().unwrap_or("")
@@ -185,18 +210,6 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 		}
 	}
 
-	// The original create event must be in the auth events
-	if !matches!(
-		auth_events_by_key.get(&(StateEventType::RoomCreate, String::new().into())),
-		Some(_) | None
-	) {
-		self.services.pdu_metadata.mark_event_rejected(event_id);
-		self.services
-			.outlier
-			.add_pdu_outlier(pdu_event.event_id(), &incoming_pdu);
-		return Err!(Request(InvalidParam("Incoming event refers to wrong create event.")));
-	}
-
 	let state_fetch = |ty: &StateEventType, sk: &str| {
 		let key = (ty.to_owned(), sk.into());
 		ready(auth_events_by_key.get(&key).map(ToOwned::to_owned))

src/service/rooms/event_handler/handle_prev_pdu.rs

@@ -46,7 +46,7 @@ pub(super) async fn handle_prev_pdu<'a, Pdu>(
 	{
 		// Exponential backoff
 		const MIN_DURATION: u64 = 5 * 60;
-		const MAX_DURATION: u64 = 60 * 60 * 24;
+		const MAX_DURATION: u64 = 60 * 60;
 		if continue_exponential_backoff_secs(MIN_DURATION, MAX_DURATION, time.elapsed(), *tries) {
 			debug!(
 				?tries,

src/service/rooms/event_handler/mod.rs

@@ -4,7 +4,6 @@
 mod fetch_state;
 mod handle_incoming_pdu;
 mod handle_outlier_pdu;
-mod handle_prev_pdu;
 mod parse_incoming_pdu;
 mod policy_server;
 mod resolve_state;
@@ -15,6 +14,7 @@
 
 use async_trait::async_trait;
 use conduwuit::{Err, Event, PduEvent, Result, Server, SyncRwLock, utils::MutexMap};
+pub use fetch_and_handle_outliers::{GET_MISSING_EVENTS_MAX_BATCH_SIZE, build_local_dag};
 use ruma::{
 	OwnedEventId, OwnedRoomId, RoomId, events::room::create::RoomCreateEventContent,
 	room_version_rules::RoomVersionRules,
@@ -22,10 +22,10 @@
 use tokio::sync::Notify;
 
 use crate::{Dep, globals, rooms, sending, server_keys};
-
 pub struct Service {
 	pub mutex_federation: RoomMutexMap,
 	pub federation_handletime: SyncRwLock<HandleTimeMap>,
+	pub last_extremity_squash: SyncRwLock<HashMap<OwnedRoomId, Instant>>,
 	services: Services,
 	server_shutdown: Notify,
 }
@@ -56,6 +56,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 		Ok(Arc::new(Self {
 			mutex_federation: RoomMutexMap::new(),
 			federation_handletime: HandleTimeMap::new().into(),
+			last_extremity_squash: SyncRwLock::new(HashMap::new()),
 			services: Services {
 				globals: args.depend::<globals::Service>("globals"),
 				sending: args.depend::<sending::Service>("sending"),
@@ -91,6 +92,11 @@ async fn memory_usage(&self, out: &mut (dyn Write + Send)) -> Result {
 	fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
 
 	fn interrupt(&self) { self.server_shutdown.notify_waiters(); }
+
+	async fn clear_cache(&self) {
+		let mut squashes = self.last_extremity_squash.write();
+		squashes.clear();
+	}
 }
 
 impl Service {

src/service/rooms/event_handler/parse_incoming_pdu.rs

@@ -7,7 +7,7 @@
 use itertools::Itertools;
 use ruma::{
 	CanonicalJsonObject, CanonicalJsonValue, EventId, OwnedEventId, OwnedRoomId, RoomId,
-	RoomVersionId,
+	RoomVersionId, room_version_rules::RoomVersionRules,
 };
 use serde_json::value::RawValue as RawJsonValue;
 
@@ -56,7 +56,10 @@ fn extract_room_id(event_type: &str, pdu: &CanonicalJsonObject) -> Result<OwnedR
 
 /// Parses every entry in an array as an event ID, returning an error if any
 /// step fails.
-fn expect_event_id_array(value: &CanonicalJsonObject, field: &str) -> Result<Vec<OwnedEventId>> {
+pub(super) fn expect_event_id_array(
+	value: &CanonicalJsonObject,
+	field: &str,
+) -> Result<Vec<OwnedEventId>> {
 	value
 		.get(field)
 		.ok_or_else(|| err!(Request(BadJson("missing field `{field}` on PDU"))))?
@@ -101,6 +104,21 @@ pub fn validate_pdu(&self, pdu: &CanonicalJsonObject) -> Result {
 }
 
 #[implement(super::Service)]
+pub async fn parse_incoming_pdu_with_known_room(
+	&self,
+	pdu: &RawJsonValue,
+	room_version_rules: &RoomVersionRules,
+) -> Result<(OwnedEventId, CanonicalJsonObject)> {
+	let (event_id, value) =
+		gen_event_id_canonical_json(pdu, room_version_rules).map_err(|e| {
+			err!(Request(InvalidParam("Could not convert event to canonical json: {e}")))
+		})?;
+	self.validate_pdu(&value)?;
+	Ok((event_id, value))
+}
+
+#[implement(super::Service)]
+#[tracing::instrument(name = "parse", skip_all)]
 pub async fn parse_incoming_pdu(&self, pdu: &RawJsonValue) -> Result<Parsed> {
 	let value = serde_json::from_str::<CanonicalJsonObject>(pdu.get()).map_err(|e| {
 		err!(BadServerResponse(debug_warn!("Error parsing incoming event {e:?}")))

src/service/rooms/event_handler/state_at_incoming.rs

@@ -5,7 +5,7 @@
 };
 
 use conduwuit::{
-	Result, debug, err, error, implement,
+	Result, debug, debug_error, err, error, implement,
 	matrix::{Event, StateMap},
 	trace,
 	utils::stream::{BroadbandExt, IterStream, ReadyExt, TryBroadbandExt, TryWidebandExt},
@@ -37,6 +37,7 @@ pub(super) async fn state_at_incoming_degree_one<Pdu>(
 		.pdu_shortstatehash(prev_event)
 		.await
 	else {
+		trace!("No shortstatehash for {prev_event}, cannot calculate one-degree state.");
 		return Ok(None);
 	};
 
@@ -99,6 +100,7 @@ pub(super) async fn state_at_incoming_resolved<Pdu>(
 				.map_ok(move |sstatehash| (sstatehash, prev_event))
 		})
 		.try_collect::<HashMap<_, _>>()
+		.inspect_err(|e| debug_error!("failed to calculate N-degree short state hashes: {e}"))
 		.await
 	else {
 		return Ok(None);

src/service/rooms/event_handler/upgrade_outlier_pdu.rs

@@ -1,8 +1,9 @@
 use std::{borrow::Borrow, sync::Arc, time::Instant};
 
 use conduwuit::{
-	Err, Result, debug, debug_info, err, implement, info, is_equal_to,
+	Err, Result, debug, debug_error, debug_info, err, implement, info, is_equal_to,
 	matrix::{Event, EventTypeExt, PduEvent, StateKey, state_res},
+	result::DebugInspect,
 	trace,
 	utils::{
 		IterStream,
@@ -23,28 +24,17 @@
 };
 
 #[implement(super::Service)]
-pub(super) async fn upgrade_outlier_to_timeline_pdu<Pdu>(
+#[tracing::instrument(name="upgrade_outlier", skip_all, fields(event_id=%incoming_pdu.event_id()))]
+pub(super) async fn upgrade_outlier_to_timeline_pdu(
 	&self,
 	incoming_pdu: PduEvent,
 	mut val: CanonicalJsonObject,
-	create_event: &Pdu,
+	create_event: &PduEvent,
 	origin: &ServerName,
 	room_id: &RoomId,
-) -> Result<Option<RawPduId>>
-where
-	Pdu: Event + Send + Sync,
-{
-	// Skip the PDU if we already have it as a timeline event
-	if let Ok(pduid) = self
-		.services
-		.timeline
-		.get_pdu_id(incoming_pdu.event_id())
-		.await
-	{
-		return Ok(Some(pduid));
-	}
-
-	let (rejected, soft_failed) = join!(
+) -> Result<Option<RawPduId>> {
+	let (pduid, rejected, soft_failed) = join!(
+		self.services.timeline.get_pdu_id(incoming_pdu.event_id()),
 		self.services
 			.pdu_metadata
 			.is_event_rejected(incoming_pdu.event_id()),
@@ -52,17 +42,27 @@ pub(super) async fn upgrade_outlier_to_timeline_pdu<Pdu>(
 			.pdu_metadata
 			.is_event_soft_failed(incoming_pdu.event_id())
 	);
-	if rejected {
-		return Err!(Request(InvalidParam("Event has been rejected")));
+	if let Ok(id) = pduid {
+		trace!(event_id=%incoming_pdu.event_id(), "Skipping upgrade of already upgraded PDU");
+		return Ok(Some(id));
+	} else if rejected {
+		return Err!(Request(Forbidden("Event has been rejected")));
 	} else if soft_failed {
-		return Err!(Request(InvalidParam("Event has been soft-failed")));
+		return Err!(Request(Forbidden("Event has been soft-failed")));
 	}
 
+	assert_eq!(
+		*create_event.kind(),
+		StateEventType::RoomCreate.into(),
+		"tried to upgrade a PDU with a create_event that is not a room create event"
+	);
+
 	debug!(
 		event_id = %incoming_pdu.event_id,
 		"Upgrading PDU from outlier to timeline"
 	);
 	let timer = Instant::now();
+	let min_depth = self.services.metadata.get_mindepth(room_id).await;
 	let room_version_rules = get_room_version_rules(create_event)?;
 
 	// 10. Fetch missing state and auth chain events by calling /state_ids at
@@ -73,21 +73,32 @@ pub(super) async fn upgrade_outlier_to_timeline_pdu<Pdu>(
 		event_id = %incoming_pdu.event_id,
 		"Resolving state at event"
 	);
-	let mut state_at_incoming_event = if incoming_pdu.prev_events().count() == 1 {
+	let state_at_incoming_event = if incoming_pdu.prev_events().count() == 1 {
 		self.state_at_incoming_degree_one(&incoming_pdu).await?
 	} else {
 		self.state_at_incoming_resolved(&incoming_pdu, room_id, &room_version_rules)
 			.await?
 	};
+	let state_at_incoming_event = match state_at_incoming_event {
+		| Some(s) => s,
+		| None => {
+			trace!("Could not calculate incoming state, asking remote {origin} for it");
+			self.fetch_state(origin, create_event, room_id, incoming_pdu.event_id())
+				.await
+				.debug_inspect_err(|e| debug_error!("Could not fetch state from {origin}: {e}"))?
+		},
+	};
 
-	if state_at_incoming_event.is_none() {
-		state_at_incoming_event = self
-			.fetch_state(origin, create_event, room_id, incoming_pdu.event_id())
-			.await?;
+	if state_at_incoming_event.is_empty()
+		&& *incoming_pdu.event_type() != StateEventType::RoomCreate.into()
+	{
+		// This can happen if the remote sends an event but cannot be reached to fetch
+		// the state at it, and all other servers in the room (which might just be the
+		// unreachable server) are unable to provide required info.
+		// returning an error here allows the upgrade to be attempted at another time.
+		return Err!(Request(Forbidden("Could not resolve incoming state at event")));
 	}
-
-	let state_at_incoming_event =
-		state_at_incoming_event.expect("we always set this to some above");
+	trace!(state_events = state_at_incoming_event.len(), "Calculated incoming state");
 
 	debug!(
 		event_id = %incoming_pdu.event_id,
@@ -382,6 +393,12 @@ pub(super) async fn upgrade_outlier_to_timeline_pdu<Pdu>(
 
 	// Event has passed all auth/stateres checks
 	drop(state_lock);
+	if incoming_pdu.depth > min_depth && incoming_pdu.state_key().is_some() {
+		self.services
+			.metadata
+			.set_mindepth(room_id, incoming_pdu.depth.into());
+		trace!("Increased room's min depth from {} to {}", min_depth, incoming_pdu.depth);
+	}
 
 	Ok(pdu_id)
 }

src/service/rooms/membership/mod.rs

@@ -1,7 +1,7 @@
 use std::{collections::HashMap, sync::Arc};
 
 use conduwuit::{
-	Err, Pdu, Result, Server, debug, debug_info, debug_warn, err, error, info, is_true,
+	Err, Event, Pdu, Result, Server, debug, debug_info, debug_warn, err, error, info, is_true,
 	matrix::{
 		StateKey,
 		event::{gen_event_id, gen_event_id_canonical_json},
@@ -34,7 +34,7 @@
 use crate::{
 	Dep, antispam, globals,
 	rooms::{
-		metadata, outlier, pdu_metadata, short,
+		event_handler, metadata, outlier, pdu_metadata, short,
 		state::{self, RoomMutexGuard},
 		state_accessor, state_cache,
 		state_compressor::{self, CompressedState, HashSetCompressStateEvent},
@@ -51,6 +51,7 @@ struct Services {
 	server: Arc<Server>,
 	db: Arc<Database>,
 	antispam: Dep<antispam::Service>,
+	event_handler: Dep<event_handler::Service>,
 	globals: Dep<globals::Service>,
 	metadata: Dep<metadata::Service>,
 	outlier: Dep<outlier::Service>,
@@ -73,6 +74,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 				server: args.server.clone(),
 				db: args.db.clone(),
 				antispam: args.depend::<antispam::Service>("antispam"),
+				event_handler: args.depend::<event_handler::Service>("rooms::event_handler"),
 				globals: args.depend::<globals::Service>("globals"),
 				metadata: args.depend::<metadata::Service>("rooms::metadata"),
 				outlier: args.depend::<outlier::Service>("rooms::outlier"),
@@ -381,8 +383,6 @@ pub async fn join_remote_room(
 
 		// It has enough fields to be called a proper event now
 		let mut join_event = join_event_stub;
-
-		info!("Asking {remote_server} for send_join in room {room_id}");
 		let send_join_request = federation::membership::create_join_event::v2::Request::new(
 			room_id.to_owned(),
 			event_id.clone(),
@@ -392,6 +392,18 @@ pub async fn join_remote_room(
 				.await,
 		);
 
+		// NOTE: send_join can take a long time to respond, but from the point of view
+		// of other servers, we may already have finished joining. This means they
+		// sometimes end up sending PDUs to us that we aren't yet ready to accept, and
+		// consequently drop. Holding the mutex over the room while processing mitigates
+		// this.
+		let _room_lock = self
+			.services
+			.event_handler
+			.mutex_federation
+			.lock(room_id.as_str())
+			.await;
+		info!("Asking {remote_server} for send_join in room {room_id}");
 		let send_join_response = match self
 			.services
 			.sending
@@ -577,7 +589,13 @@ pub async fn join_remote_room(
 		if !auth_check {
 			return Err!(Request(Forbidden("Auth check failed")));
 		}
+		let resident_before = self
+			.services
+			.state_cache
+			.server_in_room(self.services.globals.server_name(), room_id)
+			.await;
 
+		let cork = self.services.db.cork_and_flush();
 		info!("Compressing state from send_join");
 		let compressed: CompressedState = self
 			.services
@@ -626,6 +644,10 @@ pub async fn join_remote_room(
 				room_id,
 			)
 			.await?;
+		self.services
+			.metadata
+			.maybe_set_mindepth(room_id, parsed_join_pdu.depth.into())
+			.await;
 
 		info!("Setting final room state for new room");
 		// We set the room state after inserting the pdu, so that we never have a moment
@@ -633,6 +655,23 @@ pub async fn join_remote_room(
 		self.services
 			.state
 			.set_room_state(room_id, statehash_after_join, &state_lock);
+		if !resident_before {
+			// NOTE: We replace local extremities for this room if we were not a resident
+			// before. We might be doing a remote join to satisfy restricted join rules,
+			// so we don't want to do this if we're already a resident. Otherwise, we
+			// want to replace our forward extremities whole-sale in case we were
+			// desynced.
+			info!("Replacing local forward extremities");
+			self.services
+				.state
+				.set_forward_extremities(
+					room_id,
+					std::iter::once(parsed_join_pdu.event_id()),
+					&state_lock,
+				)
+				.await;
+		}
+		drop(cork);
 
 		Ok(())
 	}

src/service/rooms/metadata/mod.rs

@@ -1,9 +1,9 @@
 use std::sync::Arc;
 
 use conduwuit::{Result, implement, utils::stream::TryIgnore};
-use database::Map;
+use database::{Deserialized, Map};
 use futures::{Stream, StreamExt};
-use ruma::{OwnedRoomId, RoomId};
+use ruma::{OwnedRoomId, RoomId, UInt, uint};
 
 use crate::{Dep, rooms};
 
@@ -17,6 +17,7 @@ struct Data {
 	bannedroomids: Arc<Map>,
 	roomid_shortroomid: Arc<Map>,
 	pduid_pdu: Arc<Map>,
+	roomid_mindepth: Arc<Map>,
 }
 
 struct Services {
@@ -31,6 +32,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 				bannedroomids: args.db["bannedroomids"].clone(),
 				roomid_shortroomid: args.db["roomid_shortroomid"].clone(),
 				pduid_pdu: args.db["pduid_pdu"].clone(),
+				roomid_mindepth: args.db["roomid_mindepth"].clone(),
 			},
 			services: Services {
 				short: args.depend::<rooms::short::Service>("rooms::short"),
@@ -98,3 +100,27 @@ pub async fn is_disabled(&self, room_id: &RoomId) -> bool {
 pub async fn is_banned(&self, room_id: &RoomId) -> bool {
 	self.db.bannedroomids.get(room_id).await.is_ok()
 }
+
+#[implement(Service)]
+pub async fn get_mindepth(&self, room_id: &RoomId) -> UInt {
+	self.db
+		.roomid_mindepth
+		.get(room_id)
+		.await
+		.deserialized::<UInt>()
+		.unwrap_or_else(|_| uint!(0))
+}
+
+#[implement(Service)]
+pub fn set_mindepth(&self, room_id: &RoomId, min_depth: u64) {
+	self.db
+		.roomid_mindepth
+		.put_raw(room_id.as_bytes(), min_depth.to_be_bytes());
+}
+
+#[implement(Service)]
+pub async fn maybe_set_mindepth(&self, room_id: &RoomId, min_depth: u64) {
+	if min_depth > self.get_mindepth(room_id).await.into() {
+		self.set_mindepth(room_id, min_depth);
+	}
+}

src/service/rooms/state/mod.rs

@@ -371,6 +371,16 @@ pub async fn get_room_shortstatehash(&self, room_id: &RoomId) -> Result<ShortSta
 			.deserialized()
 	}
 
+	pub fn all_forward_extremities(
+		&self,
+	) -> impl Stream<Item = (OwnedRoomId, OwnedEventId)> + Send {
+		self.db
+			.roomid_pduleaves
+			.keys()
+			.map_ok(|(room_id, event_id): (OwnedRoomId, OwnedEventId)| (room_id, event_id))
+			.ignore_err()
+	}
+
 	pub fn get_forward_extremities<'a>(
 		&'a self,
 		room_id: &'a RoomId,

src/service/rooms/timeline/backfill.rs

@@ -221,7 +221,10 @@ pub async fn backfill_pdu(&self, origin: &ServerName, pdu: Box<RawJsonValue>) ->
 }
 
 #[implement(super::Service)]
-async fn candidate_backfill_servers(&self, room_id: &RoomId) -> HashSet<OwnedServerName> {
+pub(crate) async fn candidate_backfill_servers(
+	&self,
+	room_id: &RoomId,
+) -> HashSet<OwnedServerName> {
 	let mut candidate_backfill_servers = HashSet::new();
 
 	let power_levels = self

src/service/rooms/timeline/mod.rs

@@ -173,6 +173,10 @@ pub async fn get_non_outlier_pdu_json(
 		self.db.get_non_outlier_pdu_json(event_id).await
 	}
 
+	pub async fn non_outlier_pdu_exists(&self, event_id: &EventId) -> bool {
+		self.db.non_outlier_pdu_exists(event_id).await.is_ok()
+	}
+
 	/// Returns the pdu's id.
 	#[inline]
 	pub async fn get_pdu_id(&self, event_id: &EventId) -> Result<RawPduId> {

src/service/server_keys/request.rs

@@ -34,8 +34,9 @@ pub(super) async fn batch_notary_request<'a, S, K>(
 
 		batch
 	});
-
-	debug_assert!(!server_keys.is_empty(), "empty batch request to notary");
+	if server_keys.is_empty() {
+		return Ok(vec![]);
+	}
 
 	let mut results = Vec::new();
 	while let Some(batch) = server_keys

src/service/services.rs

@@ -11,8 +11,8 @@
 	account_data, admin, announcements, antispam, appservice, client, config, emergency,
 	federation, firstrun, globals, key_backups, mailer,
 	manager::Manager,
-	media, moderation, password_reset, presence, pusher, registration_tokens, resolver, rooms,
-	sending, server_keys,
+	media, moderation, oauth, presence, pusher, registration_tokens, resolver, rooms, sending,
+	server_keys,
 	service::{self, Args, Map, Service},
 	sync, threepid, transactions, uiaa, users,
 };
@@ -27,7 +27,7 @@ pub struct Services {
 	pub globals: Arc<globals::Service>,
 	pub key_backups: Arc<key_backups::Service>,
 	pub media: Arc<media::Service>,
-	pub password_reset: Arc<password_reset::Service>,
+	pub oauth: Arc<oauth::Service>,
 	pub mailer: Arc<mailer::Service>,
 	pub presence: Arc<presence::Service>,
 	pub pusher: Arc<pusher::Service>,
@@ -84,7 +84,7 @@ macro_rules! build {
 			globals: build!(globals::Service),
 			key_backups: build!(key_backups::Service),
 			media: build!(media::Service),
-			password_reset: build!(password_reset::Service),
+			oauth: build!(oauth::Service),
 			mailer: build!(mailer::Service),
 			presence: build!(presence::Service),
 			pusher: build!(pusher::Service),

src/service/threepid/mod.rs

@@ -9,8 +9,9 @@
 	ClientSecret, OwnedClientSecret, OwnedSessionId, SessionId,
 	api::error::{ErrorKind, LimitExceededErrorData},
 };
+use tokio::sync::MutexGuard;
 
-mod session;
+pub mod session;
 
 use crate::{
 	Args, Dep, config,
@@ -26,6 +27,7 @@ pub struct Service {
 	ratelimiter: DefaultKeyedRateLimiter<Address>,
 }
 
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
 pub enum EmailRequirement {
 	/// Users may change their email, but cannot remove it entirely.
 	Required,
@@ -219,13 +221,12 @@ pub async fn try_validate_session(
 		Ok(())
 	}
 
-	/// Consume a validated validation session, removing it from the database
-	/// and returning the newly validated email address.
-	pub async fn consume_valid_session(
+	/// Get a validated validation session.
+	pub async fn get_valid_session(
 		&self,
 		session_id: &SessionId,
 		client_secret: &ClientSecret,
-	) -> Result<Address, Cow<'static, str>> {
+	) -> Result<ValidSession<'_>, Cow<'static, str>> {
 		let mut sessions = self.sessions.lock().await;
 
 		let Some(session) = sessions.get_session(session_id) else {
@@ -235,9 +236,13 @@ pub async fn consume_valid_session(
 		if session.client_secret == client_secret
 			&& matches!(session.validation_state, ValidationState::Validated)
 		{
-			let session = sessions.remove_session(session_id);
+			let email = session.email.clone();
 
-			Ok(session.email)
+			Ok(ValidSession {
+				email,
+				session_id: session_id.to_owned(),
+				sessions,
+			})
 		} else {
 			Err("This email address has not been validated. Did you use the link that was sent \
 			     to you?"
@@ -313,3 +318,20 @@ pub async fn get_localpart_for_email(&self, email: &Address) -> Option<String> {
 			.ok()
 	}
 }
+
+pub struct ValidSession<'lock> {
+	pub email: Address,
+	session_id: OwnedSessionId,
+	sessions: MutexGuard<'lock, ValidationSessions>,
+}
+
+impl ValidSession<'_> {
+	/// Consume this session, removing it from the database and releasing the
+	/// lock it holds.
+	#[must_use]
+	pub fn consume(mut self) -> Address {
+		self.sessions.remove_session(&self.session_id);
+
+		self.email
+	}
+}

src/service/threepid/session.rs

@@ -8,14 +8,14 @@
 use ruma::{ClientSecret, OwnedClientSecret, OwnedSessionId, SessionId};
 
 #[derive(Default)]
-pub(super) struct ValidationSessions {
+pub struct ValidationSessions {
 	sessions: HashMap<OwnedSessionId, ValidationSession>,
 	client_secrets: HashMap<OwnedClientSecret, OwnedSessionId>,
 }
 
 /// A pending or completed email validation session.
 #[derive(Debug)]
-pub(crate) struct ValidationSession {
+pub struct ValidationSession {
 	/// The session's ID
 	pub session_id: OwnedSessionId,
 	/// The client's supplied client secret
@@ -28,7 +28,7 @@ pub(crate) struct ValidationSession {
 
 /// The state of an email validation session.
 #[derive(Debug)]
-pub(crate) enum ValidationState {
+pub enum ValidationState {
 	/// The session is waiting for this validation token to be provided
 	Pending(ValidationToken),
 	/// The session has been validated
@@ -36,7 +36,7 @@ pub(crate) enum ValidationState {
 }
 
 #[derive(Clone, Debug)]
-pub(crate) struct ValidationToken {
+pub struct ValidationToken {
 	pub token: String,
 	pub issued_at: SystemTime,
 }
@@ -69,7 +69,7 @@ impl ValidationSessions {
 	const RANDOM_SID_LENGTH: usize = 16;
 
 	#[must_use]
-	pub(super) fn generate_session_id() -> OwnedSessionId {
+	pub fn generate_session_id() -> OwnedSessionId {
 		SessionId::parse(utils::random_string(Self::RANDOM_SID_LENGTH)).unwrap()
 	}
 

src/service/uiaa/mod.rs

@@ -7,7 +7,7 @@
 use conduwuit::{Err, Error, Result, error, utils};
 use lettre::Address;
 use ruma::{
-	UserId,
+	DeviceId, UserId,
 	api::{
 		client::uiaa::{
 			AuthData, AuthFlow, AuthType, EmailIdentity, EmailUserIdentifier,
@@ -16,11 +16,19 @@
 		},
 		error::{ErrorKind, StandardErrorBody},
 	},
+	assign,
+};
+use serde_json::{
+	json,
+	value::{RawValue, to_raw_value},
 };
-use serde_json::value::RawValue;
 use tokio::sync::Mutex;
 
-use crate::{Dep, config, globals, registration_tokens, threepid, users};
+use crate::{
+	Dep, config, globals,
+	oauth::{self, OAuthTicket},
+	registration_tokens, threepid, users,
+};
 
 pub struct Service {
 	services: Services,
@@ -33,6 +41,7 @@ struct Services {
 	config: Dep<config::Service>,
 	registration_tokens: Dep<registration_tokens::Service>,
 	threepid: Dep<threepid::Service>,
+	oauth: Dep<oauth::Service>,
 }
 
 impl crate::Service for Service {
@@ -45,6 +54,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 				registration_tokens: args
 					.depend::<registration_tokens::Service>("registration_tokens"),
 				threepid: args.depend::<threepid::Service>("threepid"),
+				oauth: args.depend::<oauth::Service>("oauth"),
 			},
 			uiaa_sessions: Mutex::new(HashMap::new()),
 		}))
@@ -54,8 +64,56 @@ fn name(&self) -> &str { crate::service::make_name(std::module_path!()) }
 }
 
 struct UiaaSession {
+	session_metadata: UiaaSessionMetadata,
 	info: UiaaInfo,
-	identity: Identity,
+}
+
+#[derive(Clone)]
+enum UiaaSessionMetadata {
+	Legacy {
+		identity: Identity,
+	},
+	OAuth {
+		localpart: String,
+		ticket: OAuthTicket,
+	},
+}
+
+impl UiaaSessionMetadata {
+	fn into_identity(self) -> Identity {
+		match self {
+			| Self::Legacy { identity } => identity,
+			| Self::OAuth { localpart, .. } =>
+				assign!(Identity::default(), { localpart: Some(localpart) }),
+		}
+	}
+}
+
+/// Information about the user which is initiating this UIAA session.
+pub struct UiaaInitiator<'a> {
+	user_id: &'a UserId,
+	device_id: Option<&'a DeviceId>,
+	oauth_ticket: Option<OAuthTicket>,
+}
+
+impl<'a> UiaaInitiator<'a> {
+	#[must_use]
+	pub fn new(user_id: &'a UserId, device_id: Option<&'a DeviceId>) -> Self {
+		Self { user_id, device_id, oauth_ticket: None }
+	}
+
+	#[must_use]
+	pub fn with_oauth_ticket(
+		user_id: &'a UserId,
+		device_id: Option<&'a DeviceId>,
+		oauth_ticket: OAuthTicket,
+	) -> Self {
+		Self {
+			user_id,
+			device_id,
+			oauth_ticket: Some(oauth_ticket),
+		}
+	}
 }
 
 /// Information about the authenticated user's identity.
@@ -106,7 +164,7 @@ impl Identity {
 	/// Create an Identity with the localpart of the provided user ID
 	/// and all other fields set to None.
 	#[must_use]
-	pub fn from_user_id(user_id: &UserId) -> Self {
+	fn from_user_id(user_id: &UserId) -> Self {
 		Self {
 			localpart: Some(user_id.localpart().to_owned()),
 			..Default::default()
@@ -124,11 +182,11 @@ pub async fn authenticate(
 		auth: &Option<AuthData>,
 		flows: Vec<AuthFlow>,
 		params: Box<RawValue>,
-		identity: Option<Identity>,
+		initiator: Option<UiaaInitiator<'_>>,
 	) -> Result<Identity> {
 		match auth.as_ref() {
 			| None => {
-				let info = self.create_session(flows, params, identity).await;
+				let info = self.create_session(flows, params, initiator).await?;
 
 				Err(Error::Uiaa(info))
 			},
@@ -140,8 +198,8 @@ pub async fn authenticate(
 						// session if they want to start the UIAA exchange with existing
 						// authentication data. If that happens, we create a new session
 						// here.
-						self.create_session(flows, params, identity)
-							.await
+						self.create_session(flows, params, initiator)
+							.await?
 							.session
 							.unwrap()
 							.into()
@@ -161,13 +219,15 @@ pub async fn authenticate(
 	pub async fn authenticate_password(
 		&self,
 		auth: &Option<AuthData>,
-		identity: Option<Identity>,
+		user_id: &UserId,
+		device_id: Option<&DeviceId>,
+		oauth_ticket: Option<OAuthTicket>,
 	) -> Result<Identity> {
 		self.authenticate(
 			auth,
 			vec![AuthFlow::new(vec![AuthType::Password])],
 			Box::default(),
-			identity,
+			Some(UiaaInitiator { user_id, device_id, oauth_ticket }),
 		)
 		.await
 	}
@@ -183,20 +243,88 @@ async fn create_session(
 		&self,
 		flows: Vec<AuthFlow>,
 		params: Box<RawValue>,
-		identity: Option<Identity>,
-	) -> UiaaInfo {
+		initiator: Option<UiaaInitiator<'_>>,
+	) -> Result<UiaaInfo> {
 		let mut uiaa_sessions = self.uiaa_sessions.lock().await;
 
 		let session_id = utils::random_string(Self::SESSION_ID_LENGTH);
-		let mut info = assign::assign!(UiaaInfo::new(flows), {params: Some(params)});
-		info.session = Some(session_id.clone());
 
-		uiaa_sessions.insert(session_id, UiaaSession {
-			info: info.clone(),
-			identity: identity.unwrap_or_default(),
-		});
+		let mut info = assign!(UiaaInfo::new(flows), { params: Some(params), session: Some(session_id.clone()) });
 
-		info
+		let session_metadata = if let Some(initiator) = initiator {
+			let is_oauth = if let Some(device_id) = initiator.device_id {
+				self.services
+					.oauth
+					.get_session_info_for_device(initiator.user_id, device_id)
+					.await
+					.is_some()
+			} else {
+				// Appservices never have oauth sessions
+				false
+			};
+
+			if is_oauth {
+				if let Some(oauth_ticket) = initiator.oauth_ticket {
+					let ticket_url = self
+						.services
+						.config
+						.get_client_domain()
+						.join(&format!(
+							"{}{}",
+							conduwuit_core::ROUTE_PREFIX,
+							oauth_ticket.ticket_issue_path()
+						))
+						.unwrap();
+
+					info.flows = vec![AuthFlow::new(vec![AuthType::OAuth])];
+					info.params = Some(
+						to_raw_value(&json!({
+							AuthType::OAuth.as_str(): {
+								"url": ticket_url,
+							},
+							// TODO(compat): This is necessary for older versions of matrix-rust-sdk
+							"org.matrix.cross_signing_reset": {
+								"url": ticket_url,
+							}
+						}))
+						.unwrap(),
+					);
+
+					UiaaSessionMetadata::OAuth {
+						localpart: initiator.user_id.localpart().to_owned(),
+						ticket: oauth_ticket,
+					}
+				} else {
+					return Err!(Request(Forbidden(
+						"Clients authorized with OAuth cannot use this route."
+					)));
+				}
+			} else {
+				UiaaSessionMetadata::Legacy {
+					identity: Identity::from_user_id(initiator.user_id),
+				}
+			}
+		} else {
+			UiaaSessionMetadata::Legacy { identity: Identity::default() }
+		};
+
+		// Legacy sessions aren't available if OAuth is required
+		if matches!(&session_metadata, UiaaSessionMetadata::Legacy { .. })
+			&& !self
+				.services
+				.config
+				.oauth
+				.compatibility_mode
+				.uiaa_available()
+		{
+			return Err!(Request(Unrecognized(
+				"User-interactive authentication is unavailable on this server"
+			)));
+		}
+
+		uiaa_sessions.insert(session_id, UiaaSession { session_metadata, info: info.clone() });
+
+		Ok(info)
 	}
 
 	/// Proceed with UIAA authentication given a client's authorization data.
@@ -225,7 +353,7 @@ async fn continue_session(
 		}
 
 		let completed = {
-			let UiaaSession { info, identity } = session.get_mut();
+			let UiaaSession { session_metadata, info } = session.get_mut();
 
 			let auth_type = auth.auth_type().expect("auth type should be set");
 
@@ -258,12 +386,12 @@ async fn continue_session(
 
 			// If the provided stage hasn't already been completed, check it for completion
 			if !completed_stages.contains(auth_type.as_str()) {
-				match self.check_stage(auth, identity.clone()).await {
-					| Ok((completed_stage, updated_identity)) => {
+				match self.check_stage(auth, session_metadata.clone()).await {
+					| Ok((completed_stage, updated_metadata)) => {
 						info.auth_error = None;
 						completed_stages.insert(completed_stage.to_string());
 						info.completed.push(completed_stage);
-						*identity = updated_identity;
+						*session_metadata = updated_metadata;
 					},
 					| Err(error) => {
 						info.auth_error = Some(error);
@@ -279,9 +407,9 @@ async fn continue_session(
 
 		if completed {
 			// This session is complete, remove it and return success
-			let (_, UiaaSession { identity, .. }) = session.remove_entry();
+			let (_, UiaaSession { session_metadata, .. }) = session.remove_entry();
 
-			Ok(Ok(identity))
+			Ok(Ok(session_metadata.into_identity()))
 		} else {
 			// The client needs to try again, return the updated session
 			Ok(Err(session.get().info.clone()))
@@ -295,152 +423,176 @@ async fn continue_session(
 	async fn check_stage(
 		&self,
 		auth: &AuthData,
-		mut identity: Identity,
-	) -> Result<(AuthType, Identity), StandardErrorBody> {
-		// Note: This function takes ownership of `identity` because mutations to the
-		// identity must not be applied unless checking the stage succeeds. The
-		// updated identity is returned as part of the Ok value, and
-		// `continue_session` handles saving it to `uiaa_sessions`.
+		mut session_metadata: UiaaSessionMetadata,
+	) -> Result<(AuthType, UiaaSessionMetadata), StandardErrorBody> {
+		// Note: This function takes ownership of `session_metadata` because mutations
+		// to the identity (if it's a legacy session) must not be applied unless
+		// checking the stage succeeds. The updated identity is returned as part of
+		// the Ok value, and `continue_session` handles saving it to `uiaa_sessions`.
 		//
 		// This also means it's fine to mutate `identity` at any point in this function,
 		// because those mutations won't be saved unless the function returns Ok.
 
-		match auth {
-			| AuthData::Dummy(_) => Ok(AuthType::Dummy),
-			| AuthData::EmailIdentity(EmailIdentity {
-				thirdparty_id_creds: ThirdpartyIdCredentials { client_secret, sid, .. },
-				..
-			}) => {
-				match self
-					.services
-					.threepid
-					.consume_valid_session(sid, client_secret)
-					.await
-				{
-					| Ok(email) => {
-						if let Some(localpart) =
-							self.services.threepid.get_localpart_for_email(&email).await
-						{
-							identity.try_set_localpart(localpart)?;
-						}
+		let completed_auth_type = match &mut session_metadata {
+			| UiaaSessionMetadata::OAuth { localpart, ticket } => {
+				// m.oauth is the only valid stage for oauth sessions
+				assert!(
+					matches!(auth, AuthData::OAuth(_)),
+					"got non-oauth auth data for oauth session"
+				);
 
-						identity.try_set_email(email)?;
-
-						Ok(AuthType::EmailIdentity)
-					},
-					| Err(message) => Err(StandardErrorBody::new(
-						ErrorKind::ThreepidAuthFailed,
-						message.into_owned(),
-					)),
+				if self.services.oauth.try_consume_ticket(localpart, *ticket) {
+					Ok(AuthType::OAuth)
+				} else {
+					Err(StandardErrorBody::new(
+						ErrorKind::Forbidden,
+						"No OAuth ticket available".to_owned(),
+					))
 				}
 			},
-			#[allow(clippy::useless_let_if_seq)]
-			| AuthData::Password(Password { identifier, password, .. }) => {
-				let user_id_or_localpart = match identifier {
-					| UserIdentifier::Matrix(MatrixUserIdentifier { user, .. }) =>
-						user.to_owned(),
-					| UserIdentifier::Email(EmailUserIdentifier { address, .. }) => {
-						let Ok(email) = Address::try_from(address.to_owned()) else {
-							return Err(StandardErrorBody::new(
-								ErrorKind::InvalidParam,
-								"Email is malformed".to_owned(),
-							));
-						};
+			| UiaaSessionMetadata::Legacy { identity } => match auth {
+				| AuthData::Dummy(_) => Ok(AuthType::Dummy),
+				| AuthData::EmailIdentity(EmailIdentity {
+					thirdparty_id_creds: ThirdpartyIdCredentials { client_secret, sid, .. },
+					..
+				}) => {
+					match self
+						.services
+						.threepid
+						.get_valid_session(sid, client_secret)
+						.await
+					{
+						| Ok(session) => {
+							let email = session.consume();
+
+							if let Some(localpart) =
+								self.services.threepid.get_localpart_for_email(&email).await
+							{
+								identity.try_set_localpart(localpart)?;
+							}
 
-						if let Some(localpart) =
-							self.services.threepid.get_localpart_for_email(&email).await
-						{
 							identity.try_set_email(email)?;
 
-							localpart
-						} else {
-							return Err(StandardErrorBody::new(
-								ErrorKind::Forbidden,
-								"Invalid identifier or password".to_owned(),
-							));
-						}
-					},
-					| _ =>
-						return Err(StandardErrorBody::new(
-							ErrorKind::Unrecognized,
-							"Identifier type not recognized".to_owned(),
+							Ok(AuthType::EmailIdentity)
+						},
+						| Err(message) => Err(StandardErrorBody::new(
+							ErrorKind::ThreepidAuthFailed,
+							message.into_owned(),
 						)),
-				};
+					}
+				},
+				#[allow(clippy::useless_let_if_seq)]
+				| AuthData::Password(Password { identifier, password, .. }) => {
+					let user_id_or_localpart = match identifier {
+						| UserIdentifier::Matrix(MatrixUserIdentifier { user, .. }) =>
+							user.to_owned(),
+						| UserIdentifier::Email(EmailUserIdentifier { address, .. }) => {
+							let Ok(email) = Address::try_from(address.to_owned()) else {
+								return Err(StandardErrorBody::new(
+									ErrorKind::InvalidParam,
+									"Email is malformed".to_owned(),
+								));
+							};
 
-				let Ok(user_id) = UserId::parse_with_server_name(
-					user_id_or_localpart,
-					self.services.globals.server_name(),
-				) else {
-					return Err(StandardErrorBody::new(
-						ErrorKind::InvalidParam,
-						"User ID is malformed".to_owned(),
-					));
-				};
+							if let Some(localpart) =
+								self.services.threepid.get_localpart_for_email(&email).await
+							{
+								identity.try_set_email(email)?;
 
-				if self
-					.services
-					.users
-					.check_password(&user_id, password)
-					.await
-					.is_ok()
-				{
-					identity.try_set_localpart(user_id.localpart().to_owned())?;
+								localpart
+							} else {
+								return Err(StandardErrorBody::new(
+									ErrorKind::Forbidden,
+									"Invalid identifier or password".to_owned(),
+								));
+							}
+						},
+						| _ =>
+							return Err(StandardErrorBody::new(
+								ErrorKind::Unrecognized,
+								"Identifier type not recognized".to_owned(),
+							)),
+					};
 
-					Ok(AuthType::Password)
-				} else {
-					Err(StandardErrorBody::new(
-						ErrorKind::Forbidden,
-						"Invalid identifier or password".to_owned(),
-					))
-				}
-			},
-			| AuthData::ReCaptcha(ReCaptcha { response, .. }) => {
-				let Some(ref private_site_key) = self.services.config.recaptcha_private_site_key
-				else {
-					return Err(StandardErrorBody::new(
-						ErrorKind::Forbidden,
-						"ReCaptcha is not configured".to_owned(),
-					));
-				};
+					let Ok(user_id) = UserId::parse_with_server_name(
+						user_id_or_localpart,
+						self.services.globals.server_name(),
+					) else {
+						return Err(StandardErrorBody::new(
+							ErrorKind::InvalidParam,
+							"User ID is malformed".to_owned(),
+						));
+					};
 
-				match recaptcha_verify::verify_v3(private_site_key, response, None).await {
-					| Ok(()) => Ok(AuthType::ReCaptcha),
-					| Err(e) => {
-						error!("ReCaptcha verification failed: {e:?}");
+					if self
+						.services
+						.users
+						.check_password(&user_id, password)
+						.await
+						.is_ok()
+					{
+						identity.try_set_localpart(user_id.localpart().to_owned())?;
+
+						Ok(AuthType::Password)
+					} else {
 						Err(StandardErrorBody::new(
 							ErrorKind::Forbidden,
-							"ReCaptcha verification failed".to_owned(),
+							"Invalid identifier or password".to_owned(),
 						))
-					},
-				}
-			},
-			| AuthData::RegistrationToken(RegistrationToken { token, .. }) => {
-				let token = token.trim().to_owned();
+					}
+				},
+				| AuthData::ReCaptcha(ReCaptcha { response, .. }) => {
+					let Some(ref private_site_key) =
+						self.services.config.recaptcha_private_site_key
+					else {
+						return Err(StandardErrorBody::new(
+							ErrorKind::Forbidden,
+							"ReCaptcha is not configured".to_owned(),
+						));
+					};
 
-				if let Some(valid_token) = self
-					.services
-					.registration_tokens
-					.validate_token(token)
-					.await
-				{
-					self.services
+					match recaptcha_verify::verify_v3(private_site_key, response, None).await {
+						| Ok(()) => Ok(AuthType::ReCaptcha),
+						| Err(e) => {
+							error!("ReCaptcha verification failed: {e:?}");
+							Err(StandardErrorBody::new(
+								ErrorKind::CaptchaInvalid,
+								"ReCaptcha verification failed".to_owned(),
+							))
+						},
+					}
+				},
+				| AuthData::RegistrationToken(RegistrationToken { token, .. }) => {
+					let token = token.trim().to_owned();
+
+					if let Some(valid_token) = self
+						.services
 						.registration_tokens
-						.mark_token_as_used(valid_token);
+						.validate_token(token)
+						.await
+					{
+						self.services
+							.registration_tokens
+							.mark_token_as_used(valid_token);
 
-					Ok(AuthType::RegistrationToken)
-				} else {
-					Err(StandardErrorBody::new(
-						ErrorKind::Forbidden,
-						"Invalid registration token".to_owned(),
-					))
-				}
+						Ok(AuthType::RegistrationToken)
+					} else {
+						Err(StandardErrorBody::new(
+							ErrorKind::Forbidden,
+							"Invalid registration token".to_owned(),
+						))
+					}
+				},
+				| AuthData::Terms(_) => Ok(AuthType::Terms),
+				| unknown => {
+					// We already checked that the stage type is one that exists in the flow,
+					// so we can only get here if we ourselves served a flow with a stage that we
+					// don't understand.
+					panic!("tried to check an unsupported stage type: {unknown:?}");
+				},
 			},
-			| AuthData::Terms(_) => Ok(AuthType::Terms),
-			| _ => Err(StandardErrorBody::new(
-				ErrorKind::Unrecognized,
-				"Unsupported stage type".into(),
-			)),
-		}
-		.map(|auth_type| (auth_type, identity))
+		}?;
+
+		Ok((completed_auth_type, session_metadata))
 	}
 }

src/service/users/dehydrated_device.rs

@@ -54,6 +54,7 @@ pub async fn set_dehydrated_device(&self, user_id: &UserId, request: Request) ->
 		user_id,
 		&request.device_id,
 		"",
+		None,
 		request.initial_device_display_name.clone(),
 		None,
 	)
@@ -138,7 +139,6 @@ pub async fn get_dehydrated_device_id(&self, user_id: &UserId) -> Result<OwnedDe
 	level = "debug",
 	skip_all,
 	fields(%user_id),
-	ret,
 )]
 pub async fn get_dehydrated_device(&self, user_id: &UserId) -> Result<DehydratedDevice> {
 	self.db

src/service/users/mod.rs

@@ -1,13 +1,21 @@
 pub(super) mod dehydrated_device;
 
-use std::{collections::BTreeMap, mem, net::IpAddr, sync::Arc};
+use std::{
+	collections::BTreeMap,
+	mem,
+	net::IpAddr,
+	sync::Arc,
+	time::{Duration, SystemTime},
+};
 
 use conduwuit::{
-	Err, Error, Result, Server, debug_error, debug_warn, err, trace,
+	Err, Error, Result, debug_error, debug_warn, err, info, trace,
 	utils::{self, ReadyExt, stream::TryIgnore, string::Unquoted},
+	warn,
 };
 use database::{Deserialized, Ignore, Interfix, Json, Map};
-use futures::{Stream, StreamExt, TryFutureExt};
+use futures::{FutureExt, Stream, StreamExt, TryFutureExt};
+use lettre::Address;
 use ruma::{
 	DeviceId, MilliSecondsSinceUnixEpoch, OneTimeKeyAlgorithm, OneTimeKeyId, OneTimeKeyName,
 	OwnedDeviceId, OwnedKeyId, OwnedMxcUri, OwnedOneTimeKeyId, OwnedUserId, RoomId, UInt, UserId,
@@ -18,15 +26,24 @@
 	encryption::{CrossSigningKey, DeviceKeys, OneTimeKey},
 	events::{
 		AnyToDeviceEvent, GlobalAccountDataEventType, ignored_user_list::IgnoredUserListEvent,
+		push_rules::PushRulesEvent, room::message::RoomMessageEventContent,
 	},
+	push::Ruleset,
 	serde::Raw,
 	uint,
 };
 use ruminuwuity::invite_permission_config::{FilterLevel, InvitePermissionConfigEvent};
 use serde::{Deserialize, Serialize};
 use serde_json::json;
+use tracing::error;
 
-use crate::{Dep, account_data, admin, appservice, globals, rooms};
+use crate::{
+	Dep, account_data, admin,
+	appservice::{self, RegistrationInfo},
+	config, firstrun, globals, oauth,
+	rooms::{self, alias, membership},
+	threepid,
+};
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct UserSuspension {
@@ -41,6 +58,7 @@ pub struct UserSuspension {
 /// A password hash. This is only for use when setting a user's password,
 /// if the hash needs to be kept around for a while without keeping the password
 /// in memory.
+#[derive(Serialize, Deserialize)]
 pub struct HashedPassword(String);
 
 impl HashedPassword {
@@ -51,19 +69,30 @@ pub fn new(password: &str) -> Result<Self> {
 	}
 }
 
+/// The status of an access token.
+pub enum AccessTokenStatus {
+	Valid,
+	Expired,
+}
+
 pub struct Service {
 	services: Services,
 	db: Data,
 }
 
 struct Services {
-	server: Arc<Server>,
 	account_data: Dep<account_data::Service>,
 	admin: Dep<admin::Service>,
+	alias: Dep<alias::Service>,
 	appservice: Dep<appservice::Service>,
+	config: Dep<config::Service>,
+	firstrun: Dep<firstrun::Service>,
 	globals: Dep<globals::Service>,
+	membership: Dep<membership::Service>,
+	oauth: Dep<oauth::Service>,
 	state_accessor: Dep<rooms::state_accessor::Service>,
 	state_cache: Dep<rooms::state_cache::Service>,
+	threepid: Dep<threepid::Service>,
 }
 
 struct Data {
@@ -75,6 +104,7 @@ struct Data {
 	logintoken_expiresatuserid: Arc<Map>,
 	todeviceid_events: Arc<Map>,
 	token_userdeviceid: Arc<Map>,
+	userdeviceid_tokenexpires: Arc<Map>,
 	userdeviceid_metadata: Arc<Map>,
 	userdeviceid_token: Arc<Map>,
 	userfilterid_filter: Arc<Map>,
@@ -97,14 +127,19 @@ impl crate::Service for Service {
 	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 		Ok(Arc::new(Self {
 			services: Services {
-				server: args.server.clone(),
 				account_data: args.depend::<account_data::Service>("account_data"),
 				admin: args.depend::<admin::Service>("admin"),
+				alias: args.depend::<alias::Service>("alias"),
 				appservice: args.depend::<appservice::Service>("appservice"),
+				config: args.depend::<config::Service>("config"),
+				firstrun: args.depend::<firstrun::Service>("firstrun"),
 				globals: args.depend::<globals::Service>("globals"),
+				membership: args.depend::<membership::Service>("membership"),
+				oauth: args.depend::<oauth::Service>("oauth"),
 				state_accessor: args
 					.depend::<rooms::state_accessor::Service>("rooms::state_accessor"),
 				state_cache: args.depend::<rooms::state_cache::Service>("rooms::state_cache"),
+				threepid: args.depend::<threepid::Service>("threepid"),
 			},
 			db: Data {
 				keychangeid_userid: args.db["keychangeid_userid"].clone(),
@@ -131,6 +166,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 				userid_selfsigningkeyid: args.db["userid_selfsigningkeyid"].clone(),
 				userid_usersigningkeyid: args.db["userid_usersigningkeyid"].clone(),
 				useridprofilekey_value: args.db["useridprofilekey_value"].clone(),
+				userdeviceid_tokenexpires: args.db["userdeviceid_tokenexpires"].clone(),
 			},
 		}))
 	}
@@ -206,12 +242,239 @@ pub async fn create(&self, user_id: &UserId, password: Option<HashedPassword>) -
 		Ok(())
 	}
 
-	// /// Create a new account for a local human or bot user.
-	// pub async fn create_local_account(
-	// 	&self,
-	// 	username: String,
-	// 	password:
-	// )
+	/// Create a new account for a local human or bot user.
+	pub async fn create_local_account(
+		&self,
+		user_id: &UserId,
+		password: HashedPassword,
+		email: Option<Address>,
+	) {
+		self.create(user_id, Some(password))
+			.await
+			.expect("should be able to save a new local user. what happened?");
+
+		// Set an initial display name
+		{
+			let mut displayname = user_id.localpart().to_owned();
+
+			let suffix = &self.services.config.new_user_displayname_suffix;
+			if !suffix.is_empty() {
+				displayname.push(' ');
+				displayname.push_str(suffix);
+			}
+
+			self.set_displayname(user_id, Some(displayname));
+		};
+
+		// Set default push rules
+		self.services
+			.account_data
+			.update(
+				None,
+				user_id,
+				GlobalAccountDataEventType::PushRules.to_string().into(),
+				&serde_json::to_value(PushRulesEvent::new(
+					Ruleset::server_default(user_id).into(),
+				))
+				.expect("should be able to serialize push rules"),
+			)
+			.await
+			.expect("should be able to update account data");
+
+		// If the user registered with an email, associate it with their account.
+		if let Some(email) = email {
+			// This may fail if the email is already in use, but we  should have already
+			// checked that when we sent the validation email, so ignoring the error is
+			// acceptable here in the rare case that an email is sniped by another user
+			// between the validation email being sent and the account being created.
+			let _ = self
+				.services
+				.threepid
+				.associate_localpart_email(user_id.localpart(), &email)
+				.await;
+		}
+
+		// Attempt to empower the first user and disable first-run mode.
+		let was_first_user = self.services.firstrun.empower_first_user(user_id).await;
+
+		// If the registering user was not the first and we're suspending users on
+		// register, suspend them.
+		if !was_first_user && self.services.config.suspend_on_register {
+			// Note that we can still do auto joins for suspended users
+			self.suspend_account(user_id, &self.services.globals.server_user)
+				.await;
+
+			// And send an @room notice to the admin room, to prompt admins to review the
+			// new user and ideally unsuspend them if deemed appropriate.
+			if self.services.config.admin_room_notices {
+				self.services
+					.admin
+					.send_loud_message(RoomMessageEventContent::text_plain(format!(
+						"User {user_id} has been suspended as they are not the first user on \
+						 this server. Please review and unsuspend them if appropriate."
+					)))
+					.await
+					.ok();
+			}
+		}
+
+		// Autojoin the user to the configured autojoin rooms
+		for room in &self.services.config.auto_join_rooms {
+			let Ok(room_id) = self.services.alias.resolve(room).await else {
+				error!(
+					"Failed to resolve room alias to room ID when attempting to auto join \
+					 {room}, skipping"
+				);
+				continue;
+			};
+
+			if !self
+				.services
+				.state_cache
+				.server_in_room(self.services.globals.server_name(), &room_id)
+				.await
+			{
+				warn!(
+					"Skipping room {room} to automatically join as we have never joined before."
+				);
+				continue;
+			}
+
+			if let Some(room_server_name) = room.server_name() {
+				match self
+					.services
+					.membership
+					.join_room(
+						user_id,
+						&room_id,
+						Some("Automatically joining this room upon registration".to_owned()),
+						&[
+							self.services.globals.server_name().to_owned(),
+							room_server_name.to_owned(),
+						],
+					)
+					.boxed()
+					.await
+				{
+					| Err(e) => {
+						// don't return this error so we don't fail registrations
+						error!(
+							"Failed to automatically join room {room} for user {user_id}: {e}"
+						);
+					},
+					| _ => {
+						info!("Automatically joined room {room} for user {user_id}");
+					},
+				}
+			}
+		}
+
+		info!("Created new user account for {user_id}");
+	}
+
+	pub async fn determine_registration_user_id(
+		&self,
+		supplied_username: Option<String>,
+		email: Option<&Address>,
+		appservice_info: Option<&RegistrationInfo>,
+	) -> Result<OwnedUserId> {
+		const RANDOM_USER_ID_LENGTH: usize = 10;
+
+		let emergency_mode_enabled = self.services.config.emergency_password.is_some();
+
+		let supplied_username = supplied_username.or_else(|| {
+			// If the user didn't supply a username but did supply an email, use
+			// the email's user part to avoid falling back to a random username
+			email.map(|address| address.user().to_owned())
+		});
+
+		if let Some(supplied_username) = supplied_username {
+			// The user gets to pick their username. Do some validation to make sure it's
+			// acceptable.
+
+			// Don't allow registration with forbidden usernames.
+			if self
+				.services
+				.globals
+				.forbidden_usernames()
+				.is_match(&supplied_username)
+				&& !emergency_mode_enabled
+			{
+				return Err!(Request(Forbidden("Username is forbidden")));
+			}
+
+			// Create and validate the user ID
+			let user_id = match UserId::parse_with_server_name(
+				&supplied_username,
+				self.services.globals.server_name(),
+			) {
+				| Ok(user_id) => {
+					if let Err(e) = user_id.validate_strict() {
+						// Unless we are in emergency mode, we should follow synapse's behaviour
+						// on not allowing things like spaces and UTF-8 characters in
+						// usernames
+						if !emergency_mode_enabled {
+							return Err!(Request(InvalidUsername(debug_warn!(
+								"Username {supplied_username} contains disallowed characters or \
+								 spaces: {e}"
+							))));
+						}
+					}
+
+					// Don't allow registration with user IDs that aren't local
+					if !self.services.globals.user_is_local(&user_id) {
+						return Err!(Request(InvalidUsername(
+							"Username {supplied_username} is not local to this server"
+						)));
+					}
+
+					user_id
+				},
+				| Err(e) => {
+					return Err!(Request(InvalidUsername(debug_warn!(
+						"Username {supplied_username} is not valid: {e}"
+					))));
+				},
+			};
+
+			if self.exists(&user_id).await {
+				return Err!(Request(UserInUse("User ID is not available.")));
+			}
+
+			// Check that the user ID is/is not in an appservice's namespace
+			if let Some(appservice_info) = appservice_info {
+				if !appservice_info.is_user_match(&user_id) && !emergency_mode_enabled {
+					return Err!(Request(Exclusive(
+						"Username is not in this appservice's namespace."
+					)));
+				}
+			} else if self
+				.services
+				.appservice
+				.is_exclusive_user_id(&user_id)
+				.await && !emergency_mode_enabled
+			{
+				return Err!(Request(Exclusive("Username is reserved by an appservice.")));
+			}
+
+			Ok(user_id)
+		} else {
+			// The user didn't specify a username. Generate a username for
+			// them.
+
+			loop {
+				let user_id = UserId::parse_with_server_name(
+					utils::random_string(RANDOM_USER_ID_LENGTH).to_lowercase(),
+					self.services.globals.server_name(),
+				)
+				.unwrap();
+
+				if !self.exists(&user_id).await {
+					break Ok(user_id);
+				}
+			}
+		}
+	}
 
 	/// Deactivate account
 	pub async fn deactivate_account(&self, user_id: &UserId) -> Result<()> {
@@ -351,9 +614,42 @@ pub async fn is_active_local(&self, user_id: &UserId) -> bool {
 	pub async fn count(&self) -> usize { self.db.userid_password.count().await }
 
 	/// Find out which user an access token belongs to.
-	pub async fn find_from_token(&self, token: &str) -> Result<(OwnedUserId, OwnedDeviceId)> {
-		assert!(!token.is_empty(), "Empty access token");
-		self.db.token_userdeviceid.get(token).await.deserialized()
+	pub async fn find_from_token(
+		&self,
+		token: &str,
+	) -> Option<(OwnedUserId, OwnedDeviceId, AccessTokenStatus)> {
+		let user = self
+			.db
+			.token_userdeviceid
+			.get(token)
+			.await
+			.deserialized()
+			.ok();
+
+		// Check if the token has expired
+		if let Some((user_id, device_id)) = user {
+			if let Some(expires) = self
+				.db
+				.userdeviceid_tokenexpires
+				.qry(&(&user_id, &device_id))
+				.await
+				.deserialized::<u64>()
+				.ok()
+				.map(Duration::from_secs)
+			{
+				let expires_at = SystemTime::UNIX_EPOCH
+					.checked_add(expires)
+					.expect("expiry time should not overflow SystemTime");
+
+				if SystemTime::now() > expires_at {
+					return Some((user_id, device_id, AccessTokenStatus::Expired));
+				}
+			}
+
+			Some((user_id, device_id, AccessTokenStatus::Valid))
+		} else {
+			None
+		}
 	}
 
 	/// Returns an iterator over all users on this homeserver.
@@ -449,6 +745,7 @@ pub async fn create_device(
 		user_id: &UserId,
 		device_id: &DeviceId,
 		token: &str,
+		token_max_age: Option<Duration>,
 		initial_device_display_name: Option<String>,
 		client_ip: Option<String>,
 	) -> Result<()> {
@@ -466,7 +763,8 @@ pub async fn create_device(
 
 		increment(&self.db.userid_devicelistversion, user_id.as_bytes());
 		self.db.userdeviceid_metadata.put(key, Json(device));
-		self.set_token(user_id, device_id, token).await
+		self.set_token(user_id, device_id, token, token_max_age)
+			.await
 	}
 
 	/// Removes a device from a user.
@@ -482,6 +780,7 @@ pub async fn remove_device(&self, user_id: &UserId, device_id: &DeviceId) {
 		if let Ok(old_token) = self.db.userdeviceid_token.qry(&userdeviceid).await {
 			self.db.userdeviceid_token.del(userdeviceid);
 			self.db.token_userdeviceid.remove(&old_token);
+			self.db.userdeviceid_tokenexpires.del(userdeviceid);
 		}
 
 		// Remove todevice events
@@ -495,6 +794,9 @@ pub async fn remove_device(&self, user_id: &UserId, device_id: &DeviceId) {
 
 		// TODO: Remove onetimekeys
 
+		// Remove OAuth session information
+		self.services.oauth.remove_session(user_id, device_id).await;
+
 		increment(&self.db.userid_devicelistversion, user_id.as_bytes());
 
 		self.db.userdeviceid_metadata.del(userdeviceid);
@@ -550,6 +852,7 @@ pub async fn set_token(
 		user_id: &UserId,
 		device_id: &DeviceId,
 		token: &str,
+		token_max_age: Option<Duration>,
 	) -> Result<()> {
 		let key = (user_id, device_id);
 		if self.db.userdeviceid_metadata.qry(&key).await.is_err() {
@@ -576,6 +879,7 @@ pub async fn set_token(
 		// Remove old token
 		if let Ok(old_token) = self.db.userdeviceid_token.qry(&key).await {
 			self.db.token_userdeviceid.remove(&old_token);
+			self.db.userdeviceid_tokenexpires.remove(&old_token);
 			// It will be removed from userdeviceid_token by the insert later
 		}
 
@@ -583,6 +887,18 @@ pub async fn set_token(
 		self.db.userdeviceid_token.put_raw(key, token);
 		self.db.token_userdeviceid.raw_put(token, key);
 
+		if let Some(max_age) = token_max_age {
+			let expires = SystemTime::now()
+				.duration_since(SystemTime::UNIX_EPOCH)
+				.expect("system time should not be before the epoch")
+				.saturating_add(max_age)
+				.as_secs();
+
+			self.db.userdeviceid_tokenexpires.put(key, expires);
+		} else {
+			self.db.userdeviceid_tokenexpires.del(key);
+		}
+
 		Ok(())
 	}
 
@@ -1253,7 +1569,7 @@ pub async fn get_filter(
 	pub fn create_openid_token(&self, user_id: &UserId, token: &str) -> Result<u64> {
 		use std::num::Saturating as Sat;
 
-		let expires_in = self.services.server.config.openid_token_ttl;
+		let expires_in = self.services.config.openid_token_ttl;
 		let expires_at = Sat(utils::millis_since_unix_epoch()) + Sat(expires_in) * Sat(1000);
 
 		let mut value = expires_at.0.to_be_bytes().to_vec();
@@ -1297,7 +1613,7 @@ pub async fn find_from_openid_token(&self, token: &str) -> Result<OwnedUserId> {
 	pub fn create_login_token(&self, user_id: &UserId, token: &str) -> u64 {
 		use std::num::Saturating as Sat;
 
-		let expires_in = self.services.server.config.login_token_ttl;
+		let expires_in = self.services.config.login_token_ttl;
 		let expires_at = Sat(utils::millis_since_unix_epoch()) + Sat(expires_in);
 
 		let value = (expires_at.0, user_id);

src/web/Cargo.toml

@@ -22,6 +22,8 @@ crate-type = [
 conduwuit-build-metadata.workspace = true
 conduwuit-service.workspace = true
 conduwuit-core.workspace = true
+conduwuit-database.workspace = true
+conduwuit-api.workspace = true
 async-trait.workspace = true
 askama.workspace = true
 axum.workspace = true
@@ -35,9 +37,18 @@ ruma.workspace = true
 thiserror.workspace = true
 tower-http.workspace = true
 serde.workspace = true
+serde_json.workspace = true
+lettre.workspace = true
 memory-serve = "2.1.0"
 validator = { version = "0.20.0", features = ["derive"] }
 tower-sec-fetch = { version = "0.1.2", features = ["tracing"] }
+tower-sessions = { version = "0.15.0", default-features = false, features = ["axum-core"] }
+tower-sessions-core = { version = "0.15.0", features = ["deletion-task"] }
+serde_urlencoded.workspace = true
+url.workspace = true
+recaptcha-verify = { version = "0.2.0", default-features = false }
+reqwest_recaptcha = { package = "reqwest", version = "0.12.28", default-features = false, features = ["rustls-tls-native-roots-no-provider"]  } # As long as recaptcha-verify's reqwest is outdated
+form_urlencoded = "1.2.2"
 
 [build-dependencies]
 memory-serve = "2.1.0"

src/web/extract.rs

@@ -0,0 +1,48 @@
+use axum::{
+	extract::{FromRequest, FromRequestParts, Request},
+	http::{Method, request::Parts},
+};
+use serde::de::DeserializeOwned;
+
+use crate::WebError;
+
+/// An extractor which deserializes a struct from a POST request's body.
+/// For GET requests the struct will be None.
+#[derive(Debug, Clone, Copy, Default)]
+#[must_use]
+pub(crate) struct PostForm<T>(pub Option<T>);
+
+impl<T, S> FromRequest<S> for PostForm<T>
+where
+	T: DeserializeOwned,
+	S: Send + Sync,
+{
+	type Rejection = WebError;
+
+	async fn from_request(req: Request, state: &S) -> Result<Self, Self::Rejection> {
+		if req.method() == Method::POST {
+			let axum::Form(data) = axum::Form::from_request(req, state).await?;
+
+			Ok(Self(Some(data)))
+		} else {
+			Ok(Self(None))
+		}
+	}
+}
+
+/// An extractor which wraps another extractor and converts its errors into
+/// `WebError`s.
+pub(crate) struct Expect<E>(pub E);
+
+impl<E, S, R> FromRequestParts<S> for Expect<E>
+where
+	E: FromRequestParts<S, Rejection = R>,
+	WebError: From<R>,
+	S: Send + Sync,
+{
+	type Rejection = WebError;
+
+	async fn from_request_parts(parts: &mut Parts, state: &S) -> Result<Self, Self::Rejection> {
+		Ok(Self(E::from_request_parts(parts, state).await?))
+	}
+}

src/web/mod.rs

@@ -1,25 +1,34 @@
-use std::any::Any;
+use std::{any::Any, sync::Once, time::Duration};
 
 use askama::Template;
 use axum::{
 	Router,
-	extract::rejection::{FormRejection, QueryRejection},
-	http::{HeaderValue, StatusCode, header},
-	response::{Html, IntoResponse, Response},
+	extract::rejection::{FormRejection, PathRejection, QueryRejection},
+	http::StatusCode,
+	middleware::from_fn_with_state,
+	response::{Html, IntoResponse, Redirect, Response},
 };
-use conduwuit_service::state;
-use tower_http::{catch_panic::CatchPanicLayer, set_header::SetResponseHeaderLayer};
+use conduwuit_service::{Services, state};
+use tower_http::catch_panic::CatchPanicLayer;
 use tower_sec_fetch::SecFetchLayer;
+use tower_sessions::{ExpiredDeletion, SessionManagerLayer, cookie::SameSite};
 
-use crate::pages::TemplateContext;
+use crate::{
+	pages::TemplateContext,
+	session::{LoginQuery, store::RocksDbSessionStore},
+};
 
+mod extract;
 mod pages;
+mod session;
 
 type State = state::State;
 
 const CATASTROPHIC_FAILURE: &str = "cat-astrophic failure! we couldn't even render the error template. \
 please contact the team @ https://continuwuity.org";
 
+const ROUTE_PREFIX: &str = conduwuit_core::ROUTE_PREFIX;
+
 #[derive(Debug, thiserror::Error)]
 enum WebError {
 	#[error("Failed to validate form body: {0}")]
@@ -29,10 +38,16 @@ enum WebError {
 	#[error("{0}")]
 	FormRejection(#[from] FormRejection),
 	#[error("{0}")]
+	PathRejection(#[from] PathRejection),
+	#[error("{0}")]
 	BadRequest(String),
 
 	#[error("This page does not exist.")]
 	NotFound,
+	#[error("You are not allowed to request this page: {0}")]
+	Forbidden(String),
+	#[error("You must log in to access this page")]
+	LoginRequired(LoginQuery),
 
 	#[error("Failed to render template: {0}")]
 	Render(#[from] askama::Error),
@@ -52,12 +67,26 @@ struct Error {
 			context: TemplateContext,
 		}
 
+		if let Self::LoginRequired(query) = self {
+			return Redirect::to(&format!(
+				"{}/account/login?{}",
+				ROUTE_PREFIX,
+				serde_urlencoded::to_string(query).unwrap()
+			))
+			.into_response();
+		}
+
 		let status = match &self {
 			| Self::ValidationError(_)
 			| Self::BadRequest(_)
 			| Self::QueryRejection(_)
-			| Self::FormRejection(_) => StatusCode::BAD_REQUEST,
+			| Self::FormRejection(_)
+			| Self::InternalError(_) => StatusCode::BAD_REQUEST,
 			| Self::NotFound => StatusCode::NOT_FOUND,
+			| Self::Forbidden(_) => StatusCode::FORBIDDEN,
+			| Self::LoginRequired(_) => {
+				unreachable!("LoginRequired is handled earlier")
+			},
 			| _ => StatusCode::INTERNAL_SERVER_ERROR,
 		};
 
@@ -67,6 +96,7 @@ struct Error {
 			context: TemplateContext {
 				// Statically set false to prevent error pages from being indexed.
 				allow_indexing: false,
+				csp_nonce: String::new(),
 			},
 		};
 
@@ -78,21 +108,40 @@ struct Error {
 	}
 }
 
-pub fn build() -> Router<state::State> {
+static STORE_CLEANUP_TASK: Once = Once::new();
+
+pub fn build(services: &Services) -> Router<state::State> {
 	#[allow(clippy::wildcard_imports)]
 	use pages::*;
 
+	let store = RocksDbSessionStore::new(&services.db);
+
+	STORE_CLEANUP_TASK.call_once(|| {
+		services.server.runtime().spawn(
+			store
+				.clone()
+				.continuously_delete_expired(Duration::from_hours(1)),
+		);
+	});
+
 	Router::new()
 		.merge(index::build())
 		.nest(
 			"/_continuwuity/",
 			Router::new()
-				.merge(resources::build())
-				.merge(password_reset::build())
+				.nest("/about", about::build())
+				.nest("/account/", account::build())
 				.merge(debug::build())
+				.nest("/oauth2/", oauth::build())
+				.merge(resources::build())
 				.merge(threepid::build())
 				.fallback(async || WebError::NotFound),
 		)
+		.layer(
+			SessionManagerLayer::new(store)
+				.with_name("_c10y_session")
+				.with_same_site(SameSite::Lax),
+		)
 		.layer(CatchPanicLayer::custom(|panic: Box<dyn Any + Send + 'static>| {
 			let details = if let Some(s) = panic.downcast_ref::<String>() {
 				s.clone()
@@ -104,10 +153,7 @@ pub fn build() -> Router<state::State> {
 
 			WebError::Panic(details).into_response()
 		}))
-		.layer(SetResponseHeaderLayer::if_not_present(
-			header::CONTENT_SECURITY_POLICY,
-			HeaderValue::from_static("default-src 'self'; img-src 'self' data:;"),
-		))
+		.layer(from_fn_with_state(services.config.clone(), template_context_middleware))
 		.layer(SecFetchLayer::new(|policy| {
 			policy.allow_safe_methods().reject_missing_metadata();
 		}))

src/web/pages/about.rs

@@ -0,0 +1,38 @@
+use std::collections::BTreeMap;
+
+use axum::{Extension, Router, extract::State, routing::get};
+use conduwuit_core::config::TermsDocument;
+use ruma::{
+	OwnedServerName,
+	api::client::discovery::discover_support::{Contact, ContactRole},
+};
+use url::Url;
+
+use crate::{
+	pages::{Result, TemplateContext},
+	response, template,
+};
+
+pub(crate) fn build() -> Router<crate::State> { Router::new().route("/", get(get_about)) }
+
+template! {
+	struct About use "about.html.j2" {
+		server_name: OwnedServerName,
+		support_page: Option<Url>,
+		contacts: Vec<Contact>,
+		terms: BTreeMap<String, TermsDocument>
+	}
+}
+
+async fn get_about(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+) -> Result {
+	response!(About::new(
+		context,
+		services.globals.server_name().to_owned(),
+		services.config.well_known.support_page.clone(),
+		services.admin.get_support_contacts().await,
+		services.config.registration_terms.documents.clone()
+	))
+}

src/web/pages/account/cross_signing_reset.rs

@@ -0,0 +1,47 @@
+use axum::{Extension, Router, extract::State, routing::on};
+use conduwuit_service::oauth::OAuthTicket;
+
+use crate::{
+	extract::PostForm,
+	pages::{GET_POST, Result, TemplateContext, components::UserCard},
+	response,
+	session::{LoginTarget, User},
+	template,
+};
+
+pub(crate) fn build() -> Router<crate::State> {
+	Router::new().route("/", on(GET_POST, route_cross_signing_reset))
+}
+
+template! {
+	struct CrossSigningReset use "cross_signing_reset.html.j2" {
+		user_card: UserCard,
+		body: CrossSigningResetBody
+	}
+}
+
+#[derive(Debug)]
+enum CrossSigningResetBody {
+	Form,
+	Success,
+}
+
+async fn route_cross_signing_reset(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User,
+	PostForm(form): PostForm<()>,
+) -> Result {
+	let user_id = user.expect_recent(LoginTarget::CrossSigningReset)?;
+	let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+
+	if form.is_some() {
+		services
+			.oauth
+			.issue_ticket(user_id.localpart().to_owned(), OAuthTicket::CrossSigningReset);
+
+		response!(CrossSigningReset::new(context, user_card, CrossSigningResetBody::Success))
+	} else {
+		response!(CrossSigningReset::new(context, user_card, CrossSigningResetBody::Form))
+	}
+}

src/web/pages/account/deactivate.rs

@@ -0,0 +1,129 @@
+use axum::{Extension, Router, extract::State, routing::on};
+use conduwuit_api::client::full_user_deactivate;
+use futures::StreamExt;
+use ruma::{OwnedRoomId, OwnedUserId, UserId};
+use tower_sessions::Session;
+use validator::{Validate, ValidationError, ValidationErrors};
+
+use crate::{
+	extract::PostForm,
+	form,
+	pages::{
+		GET_POST, Result, TemplateContext,
+		components::{UserCard, form::Form},
+	},
+	response,
+	session::{LoginTarget, User},
+	template,
+};
+
+pub(crate) fn build() -> Router<crate::State> {
+	Router::new().route("/", on(GET_POST, route_deactivate))
+}
+
+template! {
+	struct Deactivate use "deactivate.html.j2" {
+		body: DeactivateBody
+	}
+}
+
+#[derive(Debug)]
+#[allow(clippy::large_enum_variant)]
+enum DeactivateBody {
+	Unavailable,
+	Form {
+		user_id: OwnedUserId,
+		user_card: UserCard,
+		form: Form<'static>,
+	},
+	Success,
+}
+
+form! {
+	struct DeactivateForm {
+		password: String where {
+			input_type: "password",
+			label: "Enter your password to confirm",
+			autocomplete: "current-password"
+		},
+		#[validate(required(message = "This checkbox must be checked"))]
+		confirm: Option<String> where {
+			input_type: "checkbox",
+			label: "I understand that deactivating my account cannot be undone."
+		}
+
+		submit: "Deactivate my account",
+		slowdown: true
+	}
+}
+
+async fn route_deactivate(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User,
+	session: Session,
+	PostForm(form): PostForm<DeactivateForm>,
+) -> Result {
+	let user_id = user.expect_recent(LoginTarget::Deactivate)?;
+	let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+
+	let body = {
+		if !services.config.allow_deactivation {
+			DeactivateBody::Unavailable
+		} else if let Some(form) = form {
+			if let Err(err) = validate_deactivate_form(&services, &user_id, form).await {
+				DeactivateBody::Form {
+					user_id,
+					user_card,
+					form: DeactivateForm::with_errors(context.clone(), err),
+				}
+			} else {
+				let all_joined_rooms: Vec<OwnedRoomId> = services
+					.rooms
+					.state_cache
+					.rooms_joined(&user_id)
+					.collect()
+					.await;
+
+				full_user_deactivate(&services, &user_id, &all_joined_rooms).await?;
+
+				session.clear().await;
+
+				DeactivateBody::Success
+			}
+		} else {
+			DeactivateBody::Form {
+				user_id,
+				user_card,
+				form: DeactivateForm::build(context.clone()),
+			}
+		}
+	};
+
+	response!(Deactivate::new(context, body))
+}
+
+async fn validate_deactivate_form(
+	services: &crate::State,
+	user_id: &UserId,
+	form: DeactivateForm,
+) -> Result<(), ValidationErrors> {
+	form.validate()?;
+
+	if services
+		.users
+		.check_password(user_id, &form.password)
+		.await
+		.is_err()
+	{
+		let mut errors = ValidationErrors::new();
+		errors.add(
+			"password",
+			ValidationError::new("wrong").with_message("Incorrect password".into()),
+		);
+
+		return Err(errors);
+	}
+
+	Ok(())
+}

src/web/pages/account/device.rs

@@ -0,0 +1,126 @@
+use axum::{
+	Extension, Router,
+	extract::{Path, State},
+	routing::{get, on},
+};
+use conduwuit_service::oauth::{SessionInfo, client_metadata::ClientMetadata};
+use futures::StreamExt;
+use ruma::OwnedDeviceId;
+use serde::{Deserialize, Serialize};
+
+use crate::{
+	WebError,
+	extract::{Expect, PostForm},
+	pages::{
+		GET_POST, Result, TemplateContext,
+		components::{ClientScopes, DeviceCard, DeviceCardStyle},
+	},
+	response,
+	session::{LoginTarget, User},
+	template,
+};
+
+pub(crate) fn build() -> Router<crate::State> {
+	Router::new()
+		.route("/{device}/", get(get_device_info))
+		.route("/{device}/remove", on(GET_POST, route_remove_device))
+}
+
+template! {
+	struct DeviceInfo use "device_info.html.j2" {
+		device_card: DeviceCard,
+		client_metadata: Option<(ClientMetadata, SessionInfo)>
+	}
+}
+
+async fn get_device_info(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User,
+	Expect(Path(query)): Expect<Path<DevicePath>>,
+) -> Result {
+	let user_id = user.expect(LoginTarget::RemoveDevice(query.clone()))?;
+
+	let Ok(device) = services
+		.users
+		.get_device_metadata(&user_id, &query.device)
+		.await
+	else {
+		return response!(WebError::BadRequest("Unknown device".to_owned()));
+	};
+
+	let client_metadata = async {
+		let session_info = services
+			.oauth
+			.get_session_info_for_device(&user_id, &device.device_id)
+			.await?;
+		let client_metadata = services
+			.oauth
+			.get_client_metadata(&session_info.client_id)
+			.await?;
+
+		Some((client_metadata, session_info))
+	}
+	.await;
+
+	let device_card =
+		DeviceCard::for_device(&services, &user_id, device, DeviceCardStyle::Detailed).await;
+
+	response!(DeviceInfo::new(context, device_card, client_metadata))
+}
+
+template! {
+	struct RemoveDevice use "remove_device.html.j2" {
+		body: RemoveDeviceBody
+	}
+}
+
+#[derive(Debug)]
+enum RemoveDeviceBody {
+	Form {
+		device_card: Box<DeviceCard>,
+		last_device: bool,
+	},
+	Success,
+}
+
+#[derive(Clone, Debug, Deserialize, Serialize)]
+pub(crate) struct DevicePath {
+	pub device: OwnedDeviceId,
+}
+
+async fn route_remove_device(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User,
+	Expect(Path(query)): Expect<Path<DevicePath>>,
+	PostForm(form): PostForm<()>,
+) -> Result {
+	let user_id = user.expect_recent(LoginTarget::RemoveDevice(query.clone()))?;
+
+	let Ok(device) = services
+		.users
+		.get_device_metadata(&user_id, &query.device)
+		.await
+	else {
+		return response!(WebError::BadRequest("Unknown device".to_owned()));
+	};
+
+	if form.is_some() {
+		services
+			.users
+			.remove_device(&user_id, &device.device_id)
+			.await;
+
+		response!(RemoveDevice::new(context, RemoveDeviceBody::Success))
+	} else {
+		let device_card =
+			DeviceCard::for_device(&services, &user_id, device, DeviceCardStyle::Minimal).await;
+		let last_device = services.users.all_devices_metadata(&user_id).count().await <= 1;
+
+		response!(RemoveDevice::new(context, RemoveDeviceBody::Form {
+			device_card: Box::new(device_card),
+			last_device
+		}))
+	}
+}

src/web/pages/account/email.rs

@@ -0,0 +1,210 @@
+use axum::{
+	Extension, Router,
+	extract::{Query, State},
+	routing::{get, on, post},
+};
+use conduwuit_core::warn;
+use conduwuit_service::{mailer::messages, threepid::session::ValidationSessions};
+use lettre::{Address, message::Mailbox};
+use ruma::{ClientSecret, OwnedClientSecret, OwnedSessionId};
+use serde::{Deserialize, Serialize};
+
+use crate::{
+	WebError,
+	extract::{Expect, PostForm},
+	form,
+	pages::{
+		GET_POST, Result, TemplateContext,
+		account::ThreepidQuery,
+		components::{UserCard, form::Form},
+	},
+	response,
+	session::{LoginTarget, User},
+	template,
+};
+
+pub(crate) fn build() -> Router<crate::State> {
+	Router::new()
+		.route("/change/", on(GET_POST, route_change_email))
+		.route("/change/validate", get(get_change_email_validate))
+		.route("/change/delete", post(post_delete_email))
+}
+
+template! {
+	struct ChangeEmail use "change_email.html.j2" {
+		user_card: UserCard,
+		email: Option<String>,
+		form: Form<'static>,
+		may_remove: bool
+	}
+}
+
+form! {
+	struct ChangeEmailForm {
+		email: Address where {
+			input_type: "email",
+			label: "Email address"
+		}
+
+		submit: "Change email"
+	}
+}
+
+template! {
+	struct ChangeEmailValidate use "change_email_validate.html.j2" {
+		user_card: UserCard,
+		body: ChangeEmailValidateBody
+	}
+}
+
+template! {
+	struct DeleteEmail use "delete_email.html.j2" {
+		user_card: UserCard
+	}
+}
+
+#[derive(Debug)]
+enum ChangeEmailValidateBody {
+	ValidationPending {
+		session_id: OwnedSessionId,
+		client_secret: OwnedClientSecret,
+		validation_error: bool,
+	},
+	Success,
+}
+
+async fn route_change_email(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User,
+	PostForm(form): PostForm<ChangeEmailForm>,
+) -> Result {
+	let user_id = user.expect_recent(LoginTarget::ChangeEmail)?;
+
+	let Some(form) = form else {
+		return response!(ChangeEmail::new(
+			context.clone(),
+			UserCard::for_local_user(&services, user_id.clone()).await,
+			services
+				.threepid
+				.get_email_for_localpart(user_id.localpart())
+				.await
+				.map(|address| address.to_string()),
+			ChangeEmailForm::build(context),
+			services.threepid.email_requirement().may_remove(),
+		));
+	};
+
+	let client_secret = ClientSecret::new();
+
+	let session_id = {
+		let display_name = services.users.displayname(&user_id).await.ok();
+
+		match services
+			.threepid
+			.send_validation_email(
+				Mailbox::new(display_name, form.email.clone()),
+				|verification_link| messages::ChangeEmail {
+					server_name: services.globals.server_name().as_str(),
+					user_id: Some(&user_id),
+					verification_link,
+				},
+				&client_secret,
+				0,
+			)
+			.await
+		{
+			| Ok(session_id) => session_id,
+			| Err(err) => {
+				// If we couldn't send an email, generate a random session ID to not give that
+				// away
+				warn!(
+					"Failed to send email change message for {user_id} to {}: {err}",
+					form.email
+				);
+
+				ValidationSessions::generate_session_id()
+			},
+		}
+	};
+
+	response!(ChangeEmailValidate::new(
+		context,
+		UserCard::for_local_user(&services, user_id).await,
+		ChangeEmailValidateBody::ValidationPending {
+			session_id,
+			client_secret,
+			validation_error: false
+		}
+	))
+}
+
+#[derive(Deserialize, Serialize)]
+struct ChangeEmailQuery {
+	#[serde(flatten)]
+	threepid: ThreepidQuery,
+}
+
+async fn get_change_email_validate(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	Expect(Query(ChangeEmailQuery {
+		threepid: ThreepidQuery { client_secret, session_id },
+	})): Expect<Query<ChangeEmailQuery>>,
+	user: User,
+) -> Result {
+	let user_id = user.expect(LoginTarget::ChangeEmail)?;
+	let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+
+	if !services.threepid.email_requirement().may_change() {
+		return Err(WebError::Forbidden("You may not change your email address.".to_owned()));
+	}
+
+	let Ok(session) = services
+		.threepid
+		.get_valid_session(&session_id, &client_secret)
+		.await
+	else {
+		return response!(ChangeEmailValidate::new(
+			context,
+			user_card,
+			ChangeEmailValidateBody::ValidationPending {
+				session_id,
+				client_secret,
+				validation_error: true
+			}
+		));
+	};
+
+	let new_email = session.consume();
+
+	if let Err(err) = services
+		.threepid
+		.associate_localpart_email(user_id.localpart(), &new_email)
+		.await
+	{
+		return response!(BadRequest(err.message()));
+	}
+
+	response!(ChangeEmailValidate::new(context, user_card, ChangeEmailValidateBody::Success))
+}
+
+async fn post_delete_email(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User,
+) -> Result {
+	let user_id = user.expect(LoginTarget::ChangeEmail)?;
+	let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+
+	if !services.threepid.email_requirement().may_remove() {
+		return Err(WebError::Forbidden("You may not remove your email address.".to_owned()));
+	}
+
+	let _ = services
+		.threepid
+		.disassociate_localpart_email(user_id.localpart())
+		.await;
+
+	response!(DeleteEmail::new(context, user_card))
+}

src/web/pages/account/login.rs

@@ -0,0 +1,155 @@
+use std::time::SystemTime;
+
+use axum::{
+	Extension, Router,
+	extract::{Query, RawQuery, State},
+	response::{IntoResponse, Redirect},
+	routing::{get, on},
+};
+use conduwuit_api::client::handle_login;
+use ruma::{
+	OwnedUserId,
+	api::client::uiaa::{EmailUserIdentifier, MatrixUserIdentifier, UserIdentifier},
+};
+use serde::Deserialize;
+use tower_sessions::Session;
+
+use crate::{
+	ROUTE_PREFIX, WebError,
+	extract::{Expect, PostForm},
+	pages::{
+		GET_POST, Result, TemplateContext,
+		account::register::{TrustedFlowStatus, UntrustedFlowStatus, registration_flow_status},
+		components::UserCard,
+	},
+	response,
+	session::{LoginQuery, LoginTarget, User, UserSession},
+	template,
+};
+
+pub(crate) fn build() -> Router<crate::State> {
+	Router::new()
+		.route("/login", on(GET_POST, route_login))
+		.route("/logout", get(get_logout))
+}
+
+template! {
+	struct Login use "login.html.j2" {
+		body: LoginBody,
+		login_error: Option<String>
+	}
+}
+
+#[derive(Debug)]
+enum LoginBody {
+	Unauthenticated {
+		server_name: String,
+		registration_available: bool,
+		next: Option<LoginTarget>,
+	},
+	Authenticated {
+		user_card: UserCard,
+	},
+}
+
+#[derive(Deserialize)]
+struct LoginForm {
+	identifier: Option<String>,
+	password: String,
+}
+
+async fn route_login(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	Expect(Query(LoginQuery { next, reauthenticate })): Expect<Query<LoginQuery>>,
+	session_store: Session,
+	user: User<true>,
+	PostForm(form): PostForm<LoginForm>,
+) -> Result {
+	let user_id = user.into_session().map(|session| session.user_id);
+
+	let body = match &user_id {
+		| None => {
+			let (trusted_flow_status, untrusted_flow_status) =
+				registration_flow_status(&services).await;
+
+			let registration_available =
+				matches!(trusted_flow_status, TrustedFlowStatus::Available)
+					|| matches!(untrusted_flow_status, UntrustedFlowStatus::Available { .. });
+
+			LoginBody::Unauthenticated {
+				server_name: services.globals.server_name().to_string(),
+				registration_available,
+				next: next.clone(),
+			}
+		},
+		| Some(user_id) => {
+			if !reauthenticate {
+				return response!(Redirect::to(&next.unwrap_or_default().target_path()));
+			}
+
+			let user_card = UserCard::for_local_user(&services, user_id.to_owned()).await;
+
+			LoginBody::Authenticated { user_card }
+		},
+	};
+
+	let mut template = Login::new(context, body, None);
+
+	if let Some(form) = form {
+		let login_result = match (user_id, form.identifier) {
+			| (Some(user_id), _) => {
+				// The user is already authenticated, we need to check their password
+				services
+					.users
+					.check_password(&user_id, &form.password)
+					.await
+			},
+			| (None, Some(identifier)) => {
+				// The user isn't authenticated, we need to log them in
+				let identifier = if identifier.parse::<lettre::Address>().is_ok() {
+					UserIdentifier::Email(EmailUserIdentifier::new(identifier))
+				} else {
+					UserIdentifier::Matrix(MatrixUserIdentifier::new(identifier))
+				};
+
+				handle_login(&services, Some(&identifier), &form.password, None).await
+			},
+			| (None, None) => {
+				// The user isn't authenticated and didn't supply an identity
+				return response!(WebError::BadRequest("No identity provided".to_owned()));
+			},
+		};
+
+		let user_id = match login_result {
+			| Ok(user_id) => user_id,
+			| Err(err) => {
+				let error_message = if let conduwuit_core::Error::Request(_, message, _) = err {
+					message.into_owned()
+				} else {
+					"Internal login error".to_owned()
+				};
+
+				template.login_error = Some(error_message);
+				return response!(template);
+			},
+		};
+
+		let user_session = UserSession { user_id, last_login: SystemTime::now() };
+
+		session_store
+			.insert(User::KEY, user_session)
+			.await
+			.expect("should be able to serialize user session");
+
+		return response!(Redirect::to(&next.unwrap_or_default().target_path()));
+	}
+
+	response!(template)
+}
+
+async fn get_logout(session: Session, RawQuery(query): RawQuery) -> impl IntoResponse {
+	let _ = session.remove::<OwnedUserId>(User::KEY).await;
+
+	Redirect::to(&format!("{}/account/login?{}", ROUTE_PREFIX, query.unwrap_or_default()))
+}

src/web/pages/account/mod.rs

@@ -0,0 +1,173 @@
+use axum::{
+	Extension, Router,
+	extract::{Query, State},
+	response::Redirect,
+	routing::get,
+};
+use conduwuit_core::utils::{IterStream, ReadyExt, stream::TryExpect};
+use conduwuit_service::threepid::EmailRequirement;
+use futures::StreamExt;
+use ruma::{
+	OwnedClientSecret, OwnedDeviceId, OwnedSessionId,
+	api::client::discovery::get_authorization_server_metadata::v1::AccountManagementAction,
+};
+use serde::{Deserialize, Serialize};
+
+use crate::{
+	WebError,
+	extract::Expect,
+	pages::{
+		Result, TemplateContext,
+		components::{DeviceCard, DeviceCardStyle, UserCard},
+	},
+	response,
+	session::{LoginTarget, User},
+	template,
+};
+
+pub(crate) mod cross_signing_reset;
+pub(crate) mod deactivate;
+pub(crate) mod device;
+pub(crate) mod email;
+pub(crate) mod login;
+pub(crate) mod password;
+pub(crate) mod register;
+
+pub(crate) fn build() -> Router<crate::State> {
+	#[allow(clippy::wildcard_imports)]
+	use self::*;
+
+	Router::new()
+		.route("/", get(get_account))
+		.route("/deeplink", get(get_account_deeplink))
+		.merge(login::build())
+		.nest("/password/", password::build())
+		.nest("/email/", email::build())
+		.nest("/cross_signing_reset", cross_signing_reset::build())
+		.nest("/deactivate", deactivate::build())
+		.nest("/device/", device::build())
+		.nest("/register/", register::build())
+}
+
+#[derive(Deserialize, Serialize)]
+struct ThreepidQuery {
+	client_secret: OwnedClientSecret,
+	session_id: OwnedSessionId,
+}
+
+template! {
+	struct Account use "account.html.j2" {
+		user_card: UserCard,
+		body: AccountBody
+	}
+}
+
+#[derive(Debug)]
+enum AccountBody {
+	Unlocked {
+		suspended: bool,
+		email_requirement: EmailRequirement,
+		email: Option<String>,
+		devices: Vec<DeviceCard>,
+	},
+	Locked,
+}
+
+async fn get_account(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User<true>,
+) -> Result {
+	let user_id = user.expect(LoginTarget::Account)?;
+
+	let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+
+	if services.users.is_locked(&user_id).await.unwrap() {
+		return response!(Account::new(context, user_card, AccountBody::Locked));
+	}
+
+	let email_requirement = services.threepid.email_requirement();
+	let email = services
+		.threepid
+		.get_email_for_localpart(user_id.localpart())
+		.await
+		.map(|address| address.to_string());
+
+	let dehydrated_device_id = services.users.get_dehydrated_device_id(&user_id).await.ok();
+
+	let mut devices: Vec<_> = services
+		.users
+		.all_device_ids(&user_id)
+		.then(async |device_id| {
+			services
+				.users
+				.get_device_metadata(&user_id, &device_id)
+				.await
+		})
+		.expect_ok()
+		.ready_filter(|device| {
+			dehydrated_device_id
+				.as_ref()
+				.is_none_or(|id| device.device_id != *id)
+		})
+		.collect()
+		.await;
+
+	devices.sort_unstable_by(|a, b| a.last_seen_ts.cmp(&b.last_seen_ts).reverse());
+
+	let device_cards = devices
+		.into_iter()
+		.stream()
+		.then(async |device| {
+			DeviceCard::for_device(&services, &user_id, device, DeviceCardStyle::Minimal).await
+		})
+		.collect()
+		.await;
+
+	let suspended = services.users.is_suspended(&user_id).await.unwrap();
+
+	response!(Account::new(context, user_card, AccountBody::Unlocked {
+		suspended,
+		email_requirement,
+		email,
+		devices: device_cards
+	}))
+}
+
+#[derive(Deserialize)]
+struct AccountDeeplinkQuery {
+	action: Option<AccountManagementAction>,
+	device_id: Option<OwnedDeviceId>,
+}
+
+async fn get_account_deeplink(
+	Expect(Query(query)): Expect<Query<AccountDeeplinkQuery>>,
+) -> Result {
+	let redirect_target = match query.action.unwrap_or(AccountManagementAction::Profile) {
+		| AccountManagementAction::AccountDeactivate => "deactivate".to_owned(),
+		| AccountManagementAction::CrossSigningReset => "cross_signing_reset".to_owned(),
+		| AccountManagementAction::DeviceDelete => {
+			let Some(device_id) = query.device_id else {
+				return response!(WebError::BadRequest(
+					"A device ID is required for this action".to_owned()
+				));
+			};
+
+			format!("device/{device_id}/delete")
+		},
+		| AccountManagementAction::DeviceView => {
+			let Some(device_id) = query.device_id else {
+				return response!(WebError::BadRequest(
+					"A device ID is required for this action".to_owned()
+				));
+			};
+
+			format!("device/{device_id}/")
+		},
+		| AccountManagementAction::DevicesList => "#devices".to_owned(),
+		| AccountManagementAction::Profile => String::new(),
+		| _ => return response!(WebError::BadRequest("Unknown action".to_owned())),
+	};
+
+	response!(Redirect::to(&format!("{}/account/{}", crate::ROUTE_PREFIX, redirect_target)))
+}

src/web/pages/account/password/change.rs

@@ -0,0 +1,122 @@
+use axum::{Extension, Router, extract::State, routing::on};
+use conduwuit_service::users::HashedPassword;
+use ruma::UserId;
+use validator::{Validate, ValidationError, ValidationErrors};
+
+use crate::{
+	extract::PostForm,
+	form,
+	pages::{
+		GET_POST, Result, TemplateContext,
+		components::{UserCard, form::Form},
+	},
+	response,
+	session::{LoginTarget, User},
+	template,
+};
+
+pub(crate) fn build() -> Router<crate::State> {
+	Router::new().route("/", on(GET_POST, route_change_password))
+}
+
+template! {
+	struct ChangePassword use "change_password.html.j2" {
+		user_card: UserCard,
+		body: ChangePasswordBody
+	}
+}
+
+#[derive(Debug)]
+enum ChangePasswordBody {
+	Form(Form<'static>),
+	Success,
+}
+
+form! {
+	struct ChangePasswordForm {
+		#[validate(length(min = 1, message = "Current password cannot be empty"))]
+		current_password: String where {
+			input_type: "password",
+			label: "Current password",
+			autocomplete: "current-password"
+		},
+
+		#[validate(length(min = 1, message = "New password cannot be empty"))]
+		new_password: String where {
+			input_type: "password",
+			label: "New password",
+			autocomplete: "new-password"
+		},
+
+		#[validate(must_match(other = "new_password", message = "Passwords must match"))]
+		confirm_new_password: String where {
+			input_type: "password",
+			label: "Confirm new password",
+			autocomplete: "new-password"
+		}
+
+		submit: "Change password"
+	}
+}
+
+async fn route_change_password(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User,
+	PostForm(form): PostForm<ChangePasswordForm>,
+) -> Result {
+	let user_id = user.expect(LoginTarget::ChangePassword)?;
+	let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+
+	let body = if let Some(form) = form {
+		match change_password(&services, &user_id, form).await {
+			| Ok(()) => ChangePasswordBody::Success,
+			| Err(errors) =>
+				ChangePasswordBody::Form(ChangePasswordForm::with_errors(context.clone(), errors)),
+		}
+	} else {
+		ChangePasswordBody::Form(ChangePasswordForm::build(context.clone()))
+	};
+
+	response!(ChangePassword::new(context, user_card, body))
+}
+
+async fn change_password(
+	services: &crate::State,
+	user_id: &UserId,
+	form: ChangePasswordForm,
+) -> Result<(), ValidationErrors> {
+	form.validate()?;
+
+	if services
+		.users
+		.check_password(user_id, &form.current_password)
+		.await
+		.is_err()
+	{
+		let mut errors = ValidationErrors::new();
+		errors.add(
+			"current_password",
+			ValidationError::new("wrong").with_message("Incorrect password".into()),
+		);
+
+		return Err(errors);
+	}
+
+	match HashedPassword::new(&form.new_password) {
+		| Ok(hash) => {
+			services.users.set_password(user_id, Some(hash));
+		},
+		| Err(err) => {
+			let mut errors = ValidationErrors::new();
+			errors.add(
+				"new_password",
+				ValidationError::new("malformed").with_message(err.message().into()),
+			);
+
+			return Err(errors);
+		},
+	}
+
+	Ok(())
+}