fix: Use correct error code for invalid client ID

feat: Add support for OAuth2 device auth flow
fix: Fix new database migrations running on every server startup
2026-07-16 20:41:54 +00:00 · 2026-07-13 10:01:50 -04:00 · 2026-07-12 17:32:13 -04:00 · 2026-07-12 12:31:12 -04:00 · 2026-07-12 16:28:27 +01:00 · 2026-07-12 16:11:00 +01:00
59 changed files with 2096 additions and 1359 deletions
@@ -1,3 +1,18 @@
+# Continuwuity 26.6.1 (2026-07-12)
+
+## Features
+
+- Added enforcement for new federated invite checks and corrected a bunch of related spec compliance issues along the way. Contributed by @nex. (#1952)
+
+## Bugfixes
+
+- Fixed existing accounts failing to link when logging in with OIDC if `prompt_for_localpart` was `false`. (#1942)
+- Authentication is no longer required on the `/_matrix/client/v3/account/3pid/email/requestToken` endpoint. (#1953)
+- Fixed newly created rooms failing to sync properly in clients using legacy sync.
+- Stopped appservice users from being erroneously marked as deactivated during a 26.6 database migration.
+- Whitespace will now automatically be trimmed from the start and end of the `global.oauth.oidc.client_secret_file`.
+
+
 # Continuwuity 26.6.0 (2026-07-10)

 ## Features
@@ -826,7 +826,7 @@ dependencies = [

 [[package]]
 name = "conduwuit"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "aws-lc-rs",
 "clap",
@@ -864,7 +864,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_admin"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "assign",
 "clap",
@@ -890,7 +890,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_api"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "assign",
 "async-trait",
@@ -928,7 +928,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_build_metadata"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "built",
 "cargo_metadata",
@@ -936,7 +936,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_core"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "argon2",
 "arrayvec",
@@ -1004,7 +1004,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_database"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "async-channel",
 "conduwuit_core",
@@ -1025,7 +1025,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_macros"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "cargo_toml",
 "itertools 0.15.0",
@@ -1036,7 +1036,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_router"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "assign",
 "axum",
@@ -1074,7 +1074,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_service"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "askama",
 "assign",
@@ -1126,7 +1126,7 @@ dependencies = [

 [[package]]
 name = "conduwuit_web"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "askama",
 "assign",
@@ -3253,9 +3253,9 @@ dependencies = [

 [[package]]
 name = "minimad"
-version = "0.14.0"
+version = "0.16.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "df8b688969b16915f3ecadc7829d5b7779dee4977e503f767f34136803d5c06f"
+checksum = "de632ee829aec3a874d18a4192eae64a0460b3a45c54ed556b334f6fe5a1d62f"
 dependencies = [
 "once_cell",
 ]
@@ -4539,9 +4539,9 @@ checksum = "1e061d1b48cb8d38042de4ae0a7a6401009d6143dc80d2e2d6f31f0bdd6470c7"

 [[package]]
 name = "resolvematrix"
-version = "1.1.0"
+version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a574e37f06e219dcfdb14a4f0abf56e806c4551e030aae53802d2c42b29aea33"
+checksum = "a68b9735d8c1096d8152d4dfb5a705c0135dd14d181542fd87301f8d3cb4ed03"
 dependencies = [
 "futures",
 "hickory-resolver",
@@ -4601,7 +4601,7 @@ dependencies = [
 [[package]]
 name = "ruma"
 version = "0.16.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "assign",
 "js_int",
@@ -4620,7 +4620,7 @@ dependencies = [
 [[package]]
 name = "ruma-appservice-api"
 version = "0.16.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "js_int",
 "ruma-common",
@@ -4632,7 +4632,7 @@ dependencies = [
 [[package]]
 name = "ruma-client-api"
 version = "0.24.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "as_variant",
 "assign",
@@ -4654,7 +4654,7 @@ dependencies = [
 [[package]]
 name = "ruma-common"
 version = "0.19.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "as_variant",
 "base64 0.22.1",
@@ -4687,7 +4687,7 @@ dependencies = [
 [[package]]
 name = "ruma-events"
 version = "0.34.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "as_variant",
 "indexmap 2.14.0",
@@ -4708,7 +4708,7 @@ dependencies = [
 [[package]]
 name = "ruma-federation-api"
 version = "0.15.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "bytes",
 "headers",
@@ -4731,7 +4731,7 @@ dependencies = [
 [[package]]
 name = "ruma-identifiers-validation"
 version = "0.12.1"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "js_int",
 "thiserror 2.0.18",
@@ -4740,7 +4740,7 @@ dependencies = [
 [[package]]
 name = "ruma-macros"
 version = "0.19.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "as_variant",
 "cfg-if",
@@ -4756,7 +4756,7 @@ dependencies = [
 [[package]]
 name = "ruma-push-gateway-api"
 version = "0.15.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "js_int",
 "ruma-common",
@@ -4768,7 +4768,7 @@ dependencies = [
 [[package]]
 name = "ruma-signatures"
 version = "0.21.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "base64 0.22.1",
 "ed25519-dalek",
@@ -4785,7 +4785,7 @@ dependencies = [
 [[package]]
 name = "ruma-state-res"
 version = "0.17.0"
-source = "git+https://github.com/ruma/ruma.git?rev=fca1dbc060f730c1aaf84c9c2fb1e8a587455be8#fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+source = "git+https://github.com/ruma/ruma.git?rev=9b6a2e7323649af926e4b5363d87239ee4247f4a#9b6a2e7323649af926e4b5363d87239ee4247f4a"
 dependencies = [
 "js_int",
 "ruma-common",
@@ -4799,7 +4799,7 @@ dependencies = [

 [[package]]
 name = "ruminuwuity"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "assign",
 "ruma",
@@ -5722,9 +5722,9 @@ dependencies = [

 [[package]]
 name = "termimad"
-version = "0.34.1"
+version = "0.35.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "889a9370996b74cf46016ce35b96c248a9ac36d69aab1d112b3e09bc33affa49"
+checksum = "903906afabf58273a7a90b47e0e60701cbd01731ca72ba88508b38b5539647f4"
 dependencies = [
 "coolor",
 "crokey",
@@ -6972,7 +6972,7 @@ dependencies = [

 [[package]]
 name = "xtask"
-version = "26.6.0"
+version = "26.6.1"
 dependencies = [
 "askama",
 "cargo_metadata",
@@ -12,7 +12,7 @@ license = "Apache-2.0"
 # See also `rust-toolchain.toml`
 readme = "README.md"
 repository = "https://forgejo.ellis.link/continuwuation/continuwuity"
-version = "26.6.0"
+version = "26.6.1"

 [workspace.metadata.crane]
 name = "conduwuit"
@@ -141,12 +141,6 @@ features = [
 version = "0.23.25"
 default-features = false

-[workspace.dependencies.aws-lc-sys]
-version = "0.41.0"
-
-[workspace.dependencies.aws-lc-rs]
-version = "1.17.0"
-
 [workspace.dependencies.reqwest]
 version = "0.13.2"
 default-features = false
@@ -350,7 +344,7 @@ version = "1.1.1"
 [workspace.dependencies.ruma]
 # version = "0.14.1"
 git = "https://github.com/ruma/ruma.git"
-rev = "fca1dbc060f730c1aaf84c9c2fb1e8a587455be8"
+rev = "9b6a2e7323649af926e4b5363d87239ee4247f4a"
 features = [
    "appservice-api-c",
    "client-api",
@@ -502,7 +496,7 @@ version = "0.4.9"
 default-features = false

 [workspace.dependencies.termimad]
-version = "0.34.0"
+version = "0.35.0"
 default-features = false

 [workspace.dependencies.checked_ops]
@@ -570,7 +564,7 @@ features = ["std"]
 version = "0.3.0"

 [workspace.dependencies.resolvematrix]
-version = "1.1.0"
+version = "1.2.0"

 [workspace.dependencies.serde_urlencoded]
 version = "0.7.1"
@@ -0,0 +1 @@
+Added support for the OAuth2 device authorization flow. Contributed by @ginger
@@ -0,0 +1 @@
+Fixed `global.oauth.compatibility_mode` being required, despite being ignored, when the `[global.oauth.oidc]` config section is provided.
@@ -0,0 +1 @@
+Fixed an issue with a migration that could cause user accounts imported from an identity provider to be marked as deactivated when the server started. If you have accounts affected by this issue, use `!admin users reset-password --convert-to-local-account` to reactivate them.
@@ -1 +0,0 @@
-Stopped appservice users from being erroneously marked as deactivated during a 26.6 database migration.
@@ -9,7 +9,7 @@
            "id": 15,
            "mention_room": true,
            "date": "2026-07-10",
-            "message": "[Continuwuity 26.6.0](https://forgejo.ellis.link/continuwuation/continuwuity/releases/tag/v26.6.0) is finally out! This is by far our largest release yet, and it wouldn't have been possible without our community. Thank you so much for all of your patience, support, and/or development time over the last three months <3"
+            "message": "[Continuwuity 26.6.1](https://forgejo.ellis.link/continuwuation/continuwuity/releases/tag/v26.6.1) has just been released! This release contains a bunch of bugfixes for bugs found initially after 26.6.0's release - please read the changelog before updating!"
        }
    ]
 }
@@ -43,8 +43,8 @@ let
    env = {
      CARGO_PROFILE = profile;
      RUSTFLAGS = rustflags;
-      GIT_COMMIT_HASH = self.rev or self.dirtyRev;
-      GIT_COMMIT_HASH_SHORT = self.shortRev or self.dirtyShortRev;
+      GIT_COMMIT_HASH = self.rev or self.dirtyRev or "";
+      GIT_COMMIT_HASH_SHORT = self.shortRev or self.dirtyShortRev or "";
    }
    // (lib.optionalAttrs (rocksdb != null) {
      ROCKSDB_INCLUDE_DIR = "${rocksdb}/include";
@@ -486,7 +486,7 @@ pub(super) async fn get_remote_pdu(
 						.services
 						.rooms
 						.event_handler
-						.parse_incoming_pdu(&response.pdu)
+						.parse_incoming_pdu(&response.pdu, None)
 						.boxed()
 						.await;

@@ -832,7 +832,7 @@ pub(super) async fn force_set_room_state_from_server(
 				.services
 				.rooms
 				.event_handler
-				.parse_incoming_pdu(&pdu)
+				.parse_incoming_pdu(&pdu, Some(&room_version_rules))
 				.await
 			{
 				| Ok(t) => t,
@@ -57,13 +57,11 @@ pub(crate) async fn request_3pid_management_token_via_email_route(
 	State(services): State<crate::State>,
 	body: Ruma<request_3pid_management_token_via_email::v3::Request>,
 ) -> Result<request_3pid_management_token_via_email::v3::Response> {
-	// Authentication for this endpoint is technically optional,
-	// but we require the user to be logged in
 	let sender_user = body
 		.identity
 		.as_ref()
 		.map(ClientIdentity::expect_sender_user)
-		.ok_or_else(|| err!(Request(MissingToken("Missing access token."))))??;
+		.transpose()?;

 	if !services.threepid.email_requirement().may_change() {
 		return Err!(Request(Forbidden("You may not change your email address.")));
@@ -88,7 +86,7 @@ pub(crate) async fn request_3pid_management_token_via_email_route(
 			Mailbox::new(None, email),
 			|verification_link| messages::ChangeEmail {
 				server_name: services.config.server_name.as_str(),
-				user_id: Some(sender_user),
+				user_id: sender_user,
 				verification_link,
 			},
 			&body.client_secret,
@@ -3,7 +3,7 @@
 use conduwuit::{
 	Err, Result, debug_error, err, info,
 	matrix::{event::gen_event_id_canonical_json, pdu::PartialPdu},
-	warn,
+	trace, warn,
 };
 use futures::FutureExt;
 use ruma::{
@@ -166,7 +166,7 @@ pub(crate) async fn invite_helper(
 			let invite_room_state = services
 				.rooms
 				.state
-				.summary_stripped(&pdu, room_id, recipient_user)
+				.summary_stripped(&pdu, room_id, recipient_user, true)
 				.await;

 			drop(state_lock);
@@ -193,6 +193,7 @@ pub(crate) async fn invite_helper(
 			.await
 			.ok();

+		trace!(?request, "Sending invite");
 		let response = services
 			.sending
 			.send_federation_request(recipient_user.server_name(), request)
@@ -221,7 +222,7 @@ pub(crate) async fn invite_helper(
 		let pdu_id = services
 			.rooms
 			.event_handler
-			.handle_incoming_pdu(recipient_user.server_name(), room_id, &event_id, value, true)
+			.handle_incoming_pdu(recipient_user.server_name(), room_id, &event_id, value, false)
 			.boxed()
 			.await?
 			.ok_or_else(|| {
@@ -0,0 +1,13 @@
+use axum::{Form, Json, extract::State, response::IntoResponse};
+use http::StatusCode;
+use service::oauth::grant::DeviceCodeRequest;
+
+pub(crate) async fn device_authorization_route(
+	State(services): State<crate::State>,
+	Form(request): Form<DeviceCodeRequest>,
+) -> impl IntoResponse {
+	match services.oauth.request_device_code(request).await {
+		| Ok(response) => Ok(Json(response)),
+		| Err(err) => Err((StatusCode::BAD_REQUEST, Json(err))),
+	}
+}
@@ -10,6 +10,7 @@
 use serde_json::json;
 pub(crate) use server_metadata::*;

+mod device;
 mod register_client;
 mod server_metadata;
 mod token;
@@ -20,6 +21,7 @@
 const CLIENT_REGISTER_PATH: &str = "client/register";
 const TOKEN_REVOKE_PATH: &str = "client/revoke";
 const TOKEN_PATH: &str = "grant/token";
+const DEVICE_AUTHORIZATION_PATH: &str = "device";
 const ACCOUNT_MANAGEMENT_PATH: &str = concat!(conduwuit_core::ROUTE_PREFIX, "/account/deeplink");

 pub(crate) fn router(state: crate::State) -> Router<crate::State> {
@@ -53,4 +55,5 @@ fn oauth_router() -> Router<crate::State> {
 		.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))
+		.route(concat!("/", DEVICE_AUTHORIZATION_PATH), post(device::device_authorization_route))
 }
@@ -12,8 +12,8 @@
 use crate::{
 	Ruma,
 	client::oauth::{
-		ACCOUNT_MANAGEMENT_PATH, AUTH_CODE_PATH, CLIENT_REGISTER_PATH, JWKS_URI_PATH, TOKEN_PATH,
-		TOKEN_REVOKE_PATH,
+		ACCOUNT_MANAGEMENT_PATH, AUTH_CODE_PATH, CLIENT_REGISTER_PATH, DEVICE_AUTHORIZATION_PATH,
+		JWKS_URI_PATH, TOKEN_PATH, TOKEN_REVOKE_PATH,
 	},
 };

@@ -49,7 +49,8 @@ pub(crate) async fn authorization_server_metadata(services: &Services) -> Value
 		],
 		"authorization_endpoint": endpoint_base.join(AUTH_CODE_PATH).unwrap(),
 		"code_challenge_methods_supported": ["S256"],
-		"grant_types_supported": ["authorization_code", "refresh_token"],
+		"device_authorization_endpoint": endpoint_base.join(DEVICE_AUTHORIZATION_PATH).unwrap(),
+		"grant_types_supported": ["authorization_code", "refresh_token", "urn:ietf:params:oauth:grant-type:device_code"],
 		"issuer": services.config.get_client_domain(),
 		"jwks_uri": endpoint_base.join(JWKS_URI_PATH).unwrap(),
 		"prompt_values_supported": ["create"],
@@ -381,16 +381,21 @@ async fn fetch_shortstatehashes(
 				| Some((_, pdu_after_last_sync_end)) => {
 					trace!(?pdu_after_last_sync_end.event_id, "pdu at last sync end");

-					Some(
-						services
-							.rooms
-							.state_accessor
-							.pdu_shortstatehash(&pdu_after_last_sync_end.event_id)
-							.await
-							.map_err(|err| {
-								err!("Last sync end PDU has no shortstatehash: {err}")
-							}),
-					)
+					if pdu_after_last_sync_end.kind == RoomCreate {
+						// Room create events have no previous state
+						None
+					} else {
+						Some(
+							services
+								.rooms
+								.state_accessor
+								.pdu_shortstatehash(&pdu_after_last_sync_end.event_id)
+								.await
+								.map_err(|err| {
+									err!("Last sync end PDU has no shortstatehash: {err}")
+								}),
+						)
+					}
 				},
 				| None => {
 					// No events have been sent since the last sync, or we just joined this room
@@ -1,23 +1,29 @@
+use std::collections::{HashMap, hash_map::Entry};
+
 use axum::extract::State;
 use axum_client_ip::ClientIp;
 use base64::{Engine as _, engine::general_purpose};
 use conduwuit::{
-	Err, Error, PduEvent, Result, err, error,
-	matrix::{Event, event::gen_event_id},
-	utils::{self, hash::sha256},
+	Err, Error, EventTypeExt, PduEvent, Result, debug, err, error,
+	matrix::{Event, StateKey},
+	result::FlatOk,
+	state_res, trace,
+	utils::hash::sha256,
 	warn,
 };
 use ruma::{
-	CanonicalJsonValue, UserId,
+	CanonicalJsonObject, CanonicalJsonValue, OwnedEventId, OwnedRoomId, OwnedUserId, ServerName,
+	UserId,
 	api::{
 		error::{ErrorKind, IncompatibleRoomVersionErrorData},
 		federation::membership::{RawStrippedState, create_invite},
 	},
-	events::room::member::{MembershipState, RoomMemberEventContent},
-	serde::JsonObject,
+	events::{StateEventType, room::member::MembershipState},
+	room_version_rules::RoomVersionRules,
 };
+use serde::Deserialize;

-use crate::Ruma;
+use crate::{Ruma, server::utils::validate_any_membership_event};

 /// # `PUT /_matrix/federation/v2/invite/{roomId}/{eventId}`
 ///
@@ -28,30 +34,16 @@ pub(crate) async fn create_invite_route(
 	ClientIp(client): ClientIp,
 	body: Ruma<create_invite::v2::Request>,
 ) -> Result<create_invite::v2::Response> {
-	// ACL check origin
-	services
-		.rooms
-		.event_handler
-		.acl_check(&body.identity, &body.room_id)
-		.await?;
-
 	if !services.server.supported_room_version(&body.room_version) {
 		return Err(Error::BadRequest(
 			ErrorKind::IncompatibleRoomVersion(IncompatibleRoomVersionErrorData::new(
 				body.room_version.clone(),
 			)),
-			"Server does not support this room version.",
+			"This server does not support that room version",
 		));
 	}
-
 	let room_version_rules = body.room_version.rules().unwrap();

-	if let Some(server) = body.room_id.server_name() {
-		if services.moderation.is_remote_server_forbidden(server) {
-			return Err!(Request(Forbidden("Server is banned on this homeserver.")));
-		}
-	}
-
 	if services
 		.moderation
 		.is_remote_server_forbidden(&body.identity)
@@ -61,90 +53,61 @@ pub(crate) async fn create_invite_route(
 			body.identity, body.room_id
 		);

-		return Err!(Request(Forbidden("Server is banned on this homeserver.")));
+		return Err!(Request(Forbidden("Federation denied with {}", body.identity)));
 	}

-	let mut signed_event = utils::to_canonical_object(&body.event)
-		.map_err(|_| err!(Request(InvalidParam("Invite event is invalid."))))?;
-
-	// Ensure this is a membership event
-	if signed_event
-		.get("type")
-		.expect("event must have a type")
-		.as_str()
-		.expect("type must be a string")
-		!= "m.room.member"
-	{
-		return Err!(Request(BadJson(
-			"Not allowed to send non-membership event to invite endpoint."
-		)));
-	}
-
-	let content: RoomMemberEventContent = serde_json::from_value(
-		signed_event
-			.get("content")
-			.ok_or_else(|| err!(Request(BadJson("Event missing content property"))))?
-			.clone()
-			.into(),
+	// First, validate the invite room state, so we can compare with the create
+	// event.
+	debug!(
+		event_id=%body.event_id,
+		room_id=%body.room_id,
+		room_version=?body.room_version,
+		via=?body.via,
+		"Validating invite room state for invite request"
+	);
+	let (create_event_id, state) = validate_invite_state(
+		&services,
+		&body.invite_room_state,
+		&room_version_rules,
+		body.room_id.clone(),
 	)
-	.map_err(|e| err!(Request(BadJson(warn!("Event content is empty or invalid: {e}")))))?;
+	.await?;
+	let create_event_json = state
+		.get(&StateEventType::RoomCreate.with_state_key(""))
+		.expect("must have create event in invite state by this point");

-	// Ensure this is an invite membership event
-	if content.membership != MembershipState::Invite {
-		return Err!(Request(BadJson(
-			"Not allowed to send a non-invite membership event to invite endpoint."
-		)));
-	}
-
-	// Ensure the sending user isn't a lying bozo
-	let sender_user = signed_event
+	// We can now perform the banned remote server check with the create event.
+	// N.B. this checks the sender field, which is technically incorrect for rooms
+	// v10 and below. This usually isn't the case though so sue me
+	let creator = create_event_json
 		.get("sender")
 		.and_then(|v| v.as_str())
 		.map(UserId::parse)
-		.and_then(Result::ok)
-		.ok_or_else(|| err!(Request(InvalidParam("Invalid sender property"))))?;
-
-	if sender_user.server_name() != body.identity {
-		return Err!(Request(Forbidden("Sender's server does not match the origin server.",)));
-	}
-
-	// Ensure the target user belongs to this server
-	let recipient_user = signed_event
-		.get("state_key")
-		.and_then(|v| v.as_str())
-		.map(UserId::parse)
-		.and_then(Result::ok)
-		.ok_or_else(|| err!(Request(InvalidParam("Invalid state_key property"))))?;
-
-	if !services
-		.globals
-		.server_is_ours(recipient_user.server_name())
+		.flat_ok()
+		.expect("must have valid sender in create event");
+	if services
+		.moderation
+		.is_remote_server_forbidden(creator.server_name())
 	{
-		return Err!(Request(InvalidParam("User does not belong to this homeserver.")));
+		return Err!(Request(Forbidden("Server is banned on this homeserver.")));
 	}

-	// Make sure we're not ACL'ed from their room.
-	services
-		.rooms
-		.event_handler
-		.acl_check(recipient_user.server_name(), &body.room_id)
-		.await?;
-
-	services
-		.server_keys
-		.hash_and_sign_event(&mut signed_event, &room_version_rules)
-		.map_err(|e| err!(Request(InvalidParam("Failed to sign event: {e}"))))?;
-
-	// Generate event id
-	let event_id = gen_event_id(&signed_event, &room_version_rules)?;
-
-	// Add event_id back
-	signed_event.insert("event_id".to_owned(), CanonicalJsonValue::String(event_id.to_string()));
+	// And then we can validate the member event itself
+	let (mut signed_event, sender_user, recipient_user) = validate_invite_membership_event(
+		&services,
+		&body.event,
+		&room_version_rules,
+		&body.identity,
+		create_event_id.clone(),
+		body.room_id.clone(),
+		body.event_id.clone(),
+	)
+	.await?;

 	if services.rooms.metadata.is_banned(&body.room_id).await
 		&& !services.users.is_admin(&recipient_user).await
 	{
-		return Err!(Request(Forbidden("This room is banned on this homeserver.")));
+		return Err!(Request(Forbidden("That room is banned on this homeserver.")));
 	}

 	if services.config.block_non_admin_invites && !services.users.is_admin(&recipient_user).await
@@ -161,30 +124,57 @@ pub(crate) async fn create_invite_route(
 		return Err!(Request(Forbidden("Invite rejected by antispam service.")));
 	}

+	// If we're already in the room, ensure that neither the origin nor ourselves
+	// are ACL'd.
+	let resident = services
+		.rooms
+		.state_cache
+		.server_in_room(services.globals.server_name(), &body.room_id)
+		.await;
+	if resident {
+		services
+			.rooms
+			.event_handler
+			.acl_check(&body.identity, &body.room_id)
+			.await?;
+		services
+			.rooms
+			.event_handler
+			.acl_check(recipient_user.server_name(), &body.room_id)
+			.await
+			.map_err(|_| err!(Request(Forbidden("This server is ACL'd from that room"))))?;
+	}
+
+	services
+		.server_keys
+		.hash_and_sign_event(&mut signed_event, &room_version_rules)
+		.map_err(|e| err!(Request(InvalidParam("Failed to sign event: {e}"))))?;
+
+	// Add event_id back
+	signed_event
+		.insert("event_id".to_owned(), CanonicalJsonValue::String(body.event_id.to_string()));
+
 	let mut invite_state = body.invite_room_state.clone();
-
-	let mut event: JsonObject = serde_json::from_str(body.event.get())
-		.map_err(|e| err!(Request(BadJson("Invalid invite event PDU: {e}"))))?;
-
-	event.insert("event_id".to_owned(), "$placeholder".into());
-
-	let pdu: PduEvent = serde_json::from_value(event.into())
-		.map_err(|e| err!(Request(BadJson("Invalid invite event PDU: {e}"))))?;
-
-	invite_state.push(RawStrippedState::Pdu(
-		serde_json::value::to_raw_value(&pdu).expect("PDU was just created, it must be valid"),
-	));
+	let pdu = PduEvent::from_id_val(&body.event_id, signed_event.clone())
+		.expect("must be able to create PDU object");
+	invite_state.push(RawStrippedState::Pdu(serde_json::value::to_raw_value(&signed_event)?));

 	// If we are active in the room, the remote server will notify us about the
 	// join/invite through /send. If we are not in the room, we need to manually
 	// record the invited state for client /sync through update_membership(), and
 	// send the invite PDU to the relevant appservices.
-	if !services
-		.rooms
-		.state_cache
-		.server_in_room(services.globals.server_name(), &body.room_id)
-		.await
-	{
+	if !resident {
+		// We will start by recording the room's create event as an outlier.
+		// This will allow us to recognise it later in case the sender revokes the
+		// invite over federation later. We could store more state from the invite
+		// request, but we will get that during send_join anyway.
+		// This is safe to just add directly as an outlier as we already auth checked it
+		// during validation.
+		services
+			.rooms
+			.outlier
+			.add_pdu_outlier(&create_event_id, create_event_json);
+
 		services
 			.rooms
 			.state_cache
@@ -240,3 +230,197 @@ pub(crate) async fn create_invite_route(
 			.await,
 	))
 }
+
+/// Validates the *membership event* in the invite request, per the steps listed
+/// under the invite endpoint's [spec].
+///
+/// Returns the validated JSON body, sender user ID, and recipient user ID.
+///
+/// Since this function performs a PDU format check, the create event must be
+/// known ahead of time. This implies validating the invite state before the
+/// invite event itself.
+///
+/// [spec]: https://spec.matrix.org/v1.19/server-server-api/#put_matrixfederationv2inviteroomideventid
+async fn validate_invite_membership_event(
+	services: &crate::State,
+	body: &serde_json::value::RawValue,
+	room_version_rules: &RoomVersionRules,
+	origin: &ServerName,
+	create_event_id: OwnedEventId,
+	room_id: OwnedRoomId,
+	event_id: OwnedEventId,
+) -> Result<(CanonicalJsonObject, OwnedUserId, OwnedUserId)> {
+	trace!(?body, "Invite membership event");
+	let (pdu, target_membership, sender_user, recipient_user) = validate_any_membership_event(
+		services,
+		body,
+		room_version_rules,
+		create_event_id,
+		room_id,
+		event_id,
+	)
+	.await?;
+
+	// Ensure the sender belongs to the remote that is sending the invite
+	if sender_user.server_name() != origin {
+		return Err!(Request(Forbidden("Sender belongs to a different server")));
+	}
+
+	// Ensure the target user belongs to this server
+	if !services
+		.globals
+		.server_is_ours(recipient_user.server_name())
+	{
+		return Err!(Request(InvalidParam("Recipient does not belong to this homeserver")));
+	}
+
+	if target_membership != MembershipState::Invite {
+		return Err!(Request(BadJson("Invalid membership (expected `invite`)")));
+	}
+
+	Ok((pdu, sender_user, recipient_user))
+}
+
+/// Validates the *invite state* of an invite request, per the steps listed
+/// under the endpoint's [spec].
+///
+/// Returns the create event's event ID, and the partial state map.
+///
+/// [spec]: https://spec.matrix.org/v1.19/server-server-api/#put_matrixfederationv2inviteroomideventid
+async fn validate_invite_state(
+	services: &crate::State,
+	invite_state: &[RawStrippedState],
+	room_version_rules: &RoomVersionRules,
+	room_id: OwnedRoomId,
+) -> Result<(OwnedEventId, HashMap<(StateEventType, StateKey), CanonicalJsonObject>)> {
+	trace!(?invite_state, "Raw invite state");
+	let mut invite_state_map: HashMap<(StateEventType, StateKey), _> =
+		HashMap::with_capacity(invite_state.len());
+	let mut create_event_id: Option<OwnedEventId> = None;
+
+	for (idx, invite_state_event) in invite_state.iter().cloned().enumerate() {
+		trace!(%idx, ?invite_state_event, "Invite state event");
+		// Stripped state hasn't been sent over federation since v1.16.
+		let RawStrippedState::Pdu(raw_pdu) = invite_state_event else {
+			debug!(%idx, "Invite state event is not a PDU");
+			return Err!(Request(InvalidParam(
+				"PDU in invite state (index {idx}) violates the room event format"
+			)));
+		};
+		let (state_event_room_id, state_event_id, state_event_json) = services
+			.rooms
+			.event_handler
+			.parse_incoming_pdu(&raw_pdu, Some(room_version_rules))
+			.await
+			.map_err(|e| {
+				err!(Request(InvalidParam(debug_warn!("Invalid PDU in invite state: {e}"))))
+			})?;
+
+		if state_event_room_id != room_id {
+			return Err!(Request(InvalidParam(debug_warn!(
+				%state_event_room_id,
+				%room_id,
+				"PDU in invite state ({state_event_id}) belongs to the wrong room"
+			))));
+		}
+
+		services
+			.server_keys
+			.verify_event(&state_event_json, room_version_rules)
+			.await
+			.map_err(|e| {
+				err!(Request(InvalidParam("Signature verification failed on invite event: {e}")))
+			})?;
+
+		let Some(state_key) = state_event_json.get("state_key").and_then(|k| k.as_str()) else {
+			return Err!(Request(InvalidParam(debug_info!(
+				"PDU in invite state ({state_event_id}) is not a state event"
+			))));
+		};
+		let Some(event_type) = state_event_json.get("type").and_then(|k| k.as_str()) else {
+			return Err!(Request(InvalidParam(debug_warn!(
+				"PDU in invite state ({state_event_id}) is not an event?"
+			))));
+		};
+
+		let key = StateEventType::from(event_type).with_state_key(state_key);
+		match invite_state_map.entry(key) {
+			| Entry::Occupied(entry) =>
+				return Err!(Request(InvalidParam(
+					"Duplicate state events in invite state for state key: {:?}",
+					entry.key(),
+				))),
+			| Entry::Vacant(entry) => {
+				if entry.key().0 == StateEventType::RoomCreate {
+					// Ensure this is a legal create event.
+					let pdu_event =
+						PduEvent::from_id_val(&state_event_id, state_event_json.clone())
+							.expect("must be able to create pdu event from event json");
+					debug!("Validating discovered create event in invite room state");
+					validate_invite_create_event(&pdu_event, room_version_rules).await?;
+					create_event_id = Some(state_event_id);
+				}
+				entry.insert(state_event_json);
+			},
+		}
+	}
+	let Some(create_event_id) = create_event_id else {
+		return Err!(Request(InvalidParam(debug_warn!(
+			parsed_state=?invite_state_map,
+			"Invite state does not contain the m.room.create event"
+		))));
+	};
+	invite_state_map.iter().try_for_each(|(key, event_json)| {
+		service::rooms::event_handler::Service::pdu_format_check_1(
+			event_json,
+			room_version_rules,
+			&create_event_id,
+		)
+		.map_err(|e| {
+			err!(Request(InvalidParam(
+				"PDU in invite state for {key:?} violates the room event format: {e}"
+			)))
+		})
+	})?;
+
+	Ok((create_event_id, invite_state_map))
+}
+
+#[derive(Deserialize)]
+struct MFederate {
+	#[serde(rename = "m.federate")]
+	mfederate: Option<bool>,
+}
+
+/// Validates that a create event is suitable for the invite, namely:
+///
+/// 1. It passes auth checks (aka is valid)
+/// 2. The room is federated (there's no point persisting unfederated rooms)
+async fn validate_invite_create_event(
+	pdu: &PduEvent,
+	room_version_rules: &RoomVersionRules,
+) -> Result {
+	if !state_res::auth_check(
+		room_version_rules,
+		pdu,
+		None,
+		|_, _| async {
+			unreachable!("No state should be fetched when processing a lone create event");
+		},
+		pdu,
+	)
+	.await
+	.unwrap_or_default()
+	{
+		return Err!(Request(InvalidParam("m.room.create event fails auth check")));
+	}
+
+	let can_federate = pdu.get_content::<MFederate>()?.mfederate;
+	if !can_federate.unwrap_or(true) {
+		return Err!(Request(InvalidParam(
+			"Cannot receive invites to a room with m.federate=false"
+		)));
+	}
+
+	Ok(())
+}
@@ -75,14 +75,6 @@ pub(crate) async fn create_join_event_template_route(
 		return Err!(Request(Forbidden("Server is banned on this homeserver.")));
 	}

-	if let Some(server) = body.room_id.server_name() {
-		if services.moderation.is_remote_server_forbidden(server) {
-			return Err!(Request(Forbidden(warn!(
-				"Room ID server name {server} is banned on this homeserver."
-			))));
-		}
-	}
-
 	let room_version = services.rooms.state.get_room_version(&body.room_id).await?;
 	let room_version_rules = room_version.rules().unwrap();
 	if !body.ver.contains(&room_version) {
@@ -58,12 +58,6 @@ pub(crate) async fn create_knock_event_template_route(
 		return Err!(Request(Forbidden("Server is banned on this homeserver.")));
 	}

-	if let Some(server) = body.room_id.server_name() {
-		if services.moderation.is_remote_server_forbidden(server) {
-			return Err!(Request(Forbidden("Server is banned on this homeserver.")));
-		}
-	}
-
 	let room_version = services.rooms.state.get_room_version(&body.room_id).await?;
 	let room_version_rules = room_version.rules().unwrap();

@@ -27,6 +27,7 @@ pub(crate) async fn create_leave_event_template_route(
 	{
 		info!(
 			origin = body.identity.as_str(),
+			room_id = %body.room_id,
 			"Refusing to serve make_leave for room we aren't participating in"
 		);
 		return Err!(Request(NotFound("This server is not participating in that room.")));
@@ -150,7 +150,7 @@ async fn process_inbound_transaction(
 		.pdus
 		.iter()
 		.stream()
-		.broad_then(|pdu| services.rooms.event_handler.parse_incoming_pdu(pdu))
+		.broad_then(|pdu| services.rooms.event_handler.parse_incoming_pdu(pdu, None))
 		.inspect_err(|e| warn!("Could not parse incoming PDU: {e}"))
 		.ready_filter_map(Result::ok);

@@ -241,7 +241,7 @@ async fn handle(
 	pdus: impl Stream<Item = Pdu> + Send,
 	edus: impl Stream<Item = Edu> + Send,
 ) -> std::result::Result<ResolvedMap, TransactionError> {
-	// group pdus by room
+	// Group PDUs by room for parallel processing
 	let pdus = pdus
 		.collect()
 		.map(|mut pdus: Vec<_>| {
@@ -252,7 +252,7 @@ async fn handle(
 		})
 		.await;

-	// we can evaluate rooms concurrently
+	// Evaluate rooms in parallel
 	let results: ResolvedMap = pdus
 		.into_iter()
 		.try_stream()
@@ -266,7 +266,7 @@ async fn handle(
 		.boxed()
 		.await?;

-	// evaluate edus after pdus, at least for now.
+	// Evaluate EDUs after PDUs in case some of the PDUs then forbid some EDUs.
 	edus.for_each_concurrent(automatic_width(), |edu| handle_edu(services, client, origin, edu))
 		.boxed()
 		.await;
@@ -296,20 +296,12 @@ async fn handle_room(
 	// Try to sort PDUs by their dependencies, but fall back to arbitrary order on
 	// failure (e.g., cycles). This is best-effort; proper ordering is the sender's
 	// responsibility.
-	let sorted_event_ids = if pdu_map.len() >= 2 {
-		let refmap = pdu_map
-			.iter()
-			.map(|(event_id, obj)| (event_id.clone(), obj))
-			.collect();
-		build_local_dag(&refmap, DagBuilderTree::PrevEvents)
-			.await
-			.unwrap_or_else(|e| {
-				debug_warn!("Failed to build local DAG for room {room_id}: {e}");
-				pdu_map.keys().cloned().collect()
-			})
-	} else {
-		pdu_map.keys().cloned().collect()
-	};
+	let sorted_event_ids = build_local_dag(&pdu_map, DagBuilderTree::PrevEvents)
+		.await
+		.unwrap_or_else(|e| {
+			debug_warn!("Failed to build local DAG for room {room_id}: {e}");
+			pdu_map.keys().cloned().collect()
+		});
 	let mut results = Vec::with_capacity(sorted_event_ids.len());
 	for event_id in sorted_event_ids {
 		let value = pdu_map
@@ -322,7 +314,7 @@ async fn handle_room(
 		let result = services
 			.rooms
 			.event_handler
-			.handle_incoming_pdu(origin, room_id, &event_id, value.clone(), true)
+			.handle_incoming_pdu(origin, room_id, &event_id, value, false)
 			.boxed()
 			.await
 			.map(|_| ());
@@ -2,34 +2,36 @@

 use axum::extract::State;
 use conduwuit::{
-	Err, Event, Result, at, debug, err, info,
-	matrix::event::gen_event_id_canonical_json,
-	trace,
+	Err, Event, Result, at, debug, err, info, trace,
 	utils::stream::{BroadbandExt, IterStream, TryBroadbandExt},
 	warn,
 };
 use conduwuit_service::Services;
 use futures::{FutureExt, StreamExt, TryStreamExt};
 use ruma::{
-	CanonicalJsonValue, OwnedEventId, OwnedRoomId, OwnedUserId, RoomId, ServerName,
+	CanonicalJsonObject, CanonicalJsonValue, EventId, OwnedEventId, RoomId, ServerName, UserId,
 	api::federation::membership::create_join_event,
 	assign,
 	events::{
-		StateEventType, TimelineEventType,
+		TimelineEventType,
 		room::member::{MembershipState, RoomMemberEventContent},
 	},
+	room_version_rules::RoomVersionRules,
 };
-use serde_json::value::{RawValue as RawJsonValue, to_raw_value};
+use serde_json::value::to_raw_value;

-use crate::Ruma;
+use crate::{Ruma, server::utils::validate_any_membership_event};

-/// helper method for /send_join v1 and v2
+/// Creates a join membership event for the target, returning a computed
+/// response with room state, auth chains, etc.
 #[tracing::instrument(skip(services, pdu, omit_members), fields(room_id = room_id.as_str(), origin = origin.as_str()), level = "info")]
 async fn create_join_event(
 	services: &Services,
 	origin: &ServerName,
 	room_id: &RoomId,
-	pdu: &RawJsonValue,
+	event_id: &EventId,
+	room_version_rules: &RoomVersionRules,
+	mut pdu: CanonicalJsonObject,
 	omit_members: bool,
 ) -> Result<create_join_event::v2::RoomState> {
 	if !services.rooms.metadata.exists(room_id).await {
@@ -43,6 +45,7 @@ async fn create_join_event(
 	{
 		info!(
 			origin = origin.as_str(),
+			room_id = %room_id,
 			"Refusing to serve send_join for room we aren't participating in"
 		);
 		return Err!(Request(NotFound("This server is not participating in that room.")));
@@ -64,94 +67,25 @@ async fn create_join_event(
 		.await
 		.map_err(|e| err!(Request(NotFound(error!("Room has no state: {e}")))))?;

-	// We do not add the event_id field to the pdu here because of signature and
-	// hashes checks
-	trace!("Getting room version");
-	let room_version = services.rooms.state.get_room_version(room_id).await?;
-	let room_version_rules = room_version.rules().unwrap();
-
-	trace!("Generating event ID and converting to canonical json");
-	let Ok((event_id, mut value)) = gen_event_id_canonical_json(pdu, &room_version_rules) else {
-		// Event could not be converted to canonical json
-		return Err!(Request(BadJson("Could not convert event to canonical json.")));
-	};
-
-	let event_room_id: OwnedRoomId = serde_json::from_value(
-		value
-			.get("room_id")
-			.ok_or_else(|| err!(Request(BadJson("Event missing room_id property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("room_id field is not a valid room ID: {e}")))))?;
-
-	if event_room_id != room_id {
-		return Err!(Request(BadJson("Event room_id does not match request path room ID.")));
-	}
-
-	let event_type: StateEventType = serde_json::from_value(
-		value
-			.get("type")
-			.ok_or_else(|| err!(Request(BadJson("Event missing type property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("Event has invalid state event type: {e}")))))?;
-
-	if event_type != StateEventType::RoomMember {
-		return Err!(Request(BadJson(
-			"Not allowed to send non-membership state event to join endpoint."
-		)));
-	}
+	let sender = pdu
+		.get("sender")
+		.and_then(|v| v.as_str())
+		.map(UserId::parse)
+		.and_then(Result::ok)
+		.expect("sender was already validated");

 	let content: RoomMemberEventContent = serde_json::from_value(
-		value
-			.get("content")
+		pdu.get("content")
 			.ok_or_else(|| err!(Request(BadJson("Event missing content property"))))?
 			.clone()
 			.into(),
 	)
 	.map_err(|e| err!(Request(BadJson(warn!("Event content is empty or invalid: {e}")))))?;

-	if content.membership != MembershipState::Join {
-		return Err!(Request(BadJson(
-			"Not allowed to send a non-join membership event to join endpoint."
-		)));
-	}
-
-	let sender: OwnedUserId = serde_json::from_value(
-		value
-			.get("sender")
-			.ok_or_else(|| err!(Request(BadJson("Event missing sender property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("sender property is not a valid user ID: {e}")))))?;
-
-	// check if origin server is trying to send for another server
-	if sender.server_name() != origin {
-		return Err!(Request(Forbidden("Not allowed to join on behalf of another server.")));
-	}
-
-	let state_key: OwnedUserId = serde_json::from_value(
-		value
-			.get("state_key")
-			.ok_or_else(|| err!(Request(BadJson("Event missing state_key property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("State key is not a valid user ID: {e}")))))?;
-
-	if state_key != sender {
-		return Err!(Request(BadJson("State key does not match sender user.")));
-	}
-
 	if let Some(authorising_user) = content.join_authorized_via_users_server {
-		use ruma::RoomVersionId::*;
-
-		if matches!(room_version, V1 | V2 | V3 | V4 | V5 | V6 | V7) {
+		if !room_version_rules.authorization.restricted_join_rule {
 			return Err!(Request(InvalidParam(
-				"Room version {room_version} does not support restricted rooms but \
+				"Room version does not support restricted rooms but \
 				 join_authorised_via_users_server ({authorising_user}) was found in the event."
 			)));
 		}
@@ -174,8 +108,7 @@ async fn create_join_event(
 				 they cannot authorise your join."
 			)));
 		}
-
-		if !super::user_can_perform_restricted_join(services, &state_key, room_id).await? {
+		if !super::user_can_perform_restricted_join(services, &sender, room_id).await? {
 			return Err!(Request(UnableToAuthorizeJoin(
 				"Joining user did not pass restricted room's rules."
 			)));
@@ -183,7 +116,7 @@ async fn create_join_event(

 		services
 			.server_keys
-			.hash_and_sign_event(&mut value, &room_version_rules)
+			.hash_and_sign_event(&mut pdu, room_version_rules)
 			.map_err(|e| {
 				err!(Request(InvalidParam(warn!("Failed to sign send_join event: {e}"))))
 			})?;
@@ -200,7 +133,7 @@ async fn create_join_event(
 	let pdu_id = services
 		.rooms
 		.event_handler
-		.handle_incoming_pdu(sender.server_name(), room_id, &event_id, value.clone(), true)
+		.handle_incoming_pdu(sender.server_name(), room_id, event_id, pdu.clone(), false)
 		.boxed()
 		.await?
 		.ok_or_else(|| err!(Request(InvalidParam("Could not accept as timeline event."))))?;
@@ -220,14 +153,12 @@ async fn create_join_event(
 		.iter()
 		.try_stream()
 		.broad_filter_map(|event_id| async move {
-			if omit_members {
-				if let Ok(e) = event_id.as_ref() {
-					let pdu = services.rooms.timeline.get_pdu(e).await;
-					if pdu.is_ok_and(|p| *p.kind() == TimelineEventType::RoomMember) {
-						trace!("omitting member event {e:?} from returned state");
-						// skip members
-						return None;
-					}
+			if omit_members && let Ok(e) = event_id.as_ref() {
+				let pdu = services.rooms.timeline.get_pdu(e).await;
+				if pdu.is_ok_and(|p| *p.kind() == TimelineEventType::RoomMember) {
+					trace!("omitting member event {e:?} from returned state");
+					// skip members
+					return None;
 				}
 			}
 			Some(event_id)
@@ -289,7 +220,7 @@ async fn create_join_event(
 	Ok(assign!(create_join_event::v2::RoomState::new(), {
 		auth_chain,
 		state,
-		event: to_raw_value(&CanonicalJsonValue::Object(value)).ok(),
+		event: to_raw_value(&CanonicalJsonValue::Object(pdu)).ok(),
 		members_omitted: omit_members,
 		servers_in_room,
 	}))
@@ -309,24 +240,45 @@ pub(crate) async fn create_join_event_v2_route(
 		return Err!(Request(Forbidden("Server is banned on this homeserver.")));
 	}

-	if let Some(server) = body.room_id.server_name() {
-		if services.moderation.is_remote_server_forbidden(server) {
-			warn!(
-				"Server {} tried joining room ID {} through us which has a server name that is \
-				 globally forbidden. Rejecting.",
-				body.identity, &body.room_id,
-			);
-			return Err!(Request(Forbidden(warn!(
-				"Room ID server name {server} is banned on this homeserver."
-			))));
-		}
+	let room_version = services.rooms.state.get_room_version(&body.room_id).await?;
+	let create_event = services
+		.rooms
+		.state_accessor
+		.get_room_create_event(&body.room_id)
+		.await;
+	let room_version_rules = room_version.rules().unwrap();
+
+	let (value, membership, sender, target) = validate_any_membership_event(
+		&services,
+		&body.pdu,
+		&room_version_rules,
+		create_event.event_id.clone(),
+		body.room_id.clone(),
+		body.event_id.clone(),
+	)
+	.await?;
+	if membership != MembershipState::Join {
+		return Err!(Request(InvalidParam("Invalid membership (expected `join`)")));
+	}
+	if sender.server_name() != body.identity {
+		return Err!(Request(InvalidParam("Sender belongs to a different server")));
+	}
+	if sender != target {
+		return Err!(Request(InvalidParam("Sender does not match state key")));
 	}

 	let now = Instant::now();
-	let room_state =
-		create_join_event(&services, &body.identity, &body.room_id, &body.pdu, body.omit_members)
-			.boxed()
-			.await?;
+	let room_state = create_join_event(
+		&services,
+		&body.identity,
+		&body.room_id,
+		&body.event_id,
+		&room_version_rules,
+		value,
+		body.omit_members,
+	)
+	.boxed()
+	.await?;
 	info!(
 		"Finished sending a join for {} in {} in {:?}",
 		body.identity,
@@ -1,21 +1,11 @@
 use axum::extract::State;
-use conduwuit::{
-	Err, Result, err, info,
-	matrix::{event::gen_event_id_canonical_json, pdu::PduEvent},
-	warn,
-};
+use conduwuit::{Err, Event, Result, debug_info, err, matrix::pdu::PduEvent, warn};
 use futures::FutureExt;
 use ruma::{
-	OwnedUserId,
-	api::federation::membership::create_knock_event,
-	events::{
-		StateEventType,
-		room::member::{MembershipState, RoomMemberEventContent},
-	},
-	serde::JsonObject,
+	api::federation::membership::create_knock_event, events::room::member::MembershipState,
 };

-use crate::Ruma;
+use crate::{Ruma, server::utils::validate_any_membership_event};

 /// # `PUT /_matrix/federation/v1/send_knock/{roomId}/{eventId}`
 ///
@@ -33,18 +23,7 @@ pub(crate) async fn create_knock_event_v1_route(
 			 forbidden. Rejecting.",
 			body.identity, &body.room_id,
 		);
-		return Err!(Request(Forbidden("Server is banned on this homeserver.")));
-	}
-
-	if let Some(server) = body.room_id.server_name() {
-		if services.moderation.is_remote_server_forbidden(server) {
-			warn!(
-				"Server {} tried knocking room ID {} which has a server name that is globally \
-				 forbidden. Rejecting.",
-				body.identity, &body.room_id,
-			);
-			return Err!(Request(Forbidden("Server is banned on this homeserver.")));
-		}
+		return Err!(Request(Forbidden("Federation denied with {}", body.identity)));
 	}

 	if !services.rooms.metadata.exists(&body.room_id).await {
@@ -57,8 +36,9 @@ pub(crate) async fn create_knock_event_v1_route(
 		.server_in_room(services.globals.server_name(), &body.room_id)
 		.await
 	{
-		info!(
+		debug_info!(
 			origin = body.identity.as_str(),
+			room_id = %body.room_id,
 			"Refusing to serve send_knock for room we aren't participating in"
 		);
 		return Err!(Request(NotFound("This server is not participating in that room.")));
@@ -72,88 +52,40 @@ pub(crate) async fn create_knock_event_v1_route(
 		.await?;

 	let room_version = services.rooms.state.get_room_version(&body.room_id).await?;
+	let create_event = services
+		.rooms
+		.state_accessor
+		.get_room_create_event(&body.room_id)
+		.await;
 	let room_version_rules = room_version.rules().unwrap();

 	if !room_version_rules.authorization.knocking {
 		return Err!(Request(Forbidden("Room version does not support knocking.")));
 	}

-	let Ok((event_id, value)) = gen_event_id_canonical_json(&body.pdu, &room_version_rules)
-	else {
-		// Event could not be converted to canonical json
-		return Err!(Request(InvalidParam("Could not convert event to canonical json.")));
-	};
-
-	let event_type: StateEventType = serde_json::from_value(
-		value
-			.get("type")
-			.ok_or_else(|| err!(Request(InvalidParam("Event has no event type."))))?
-			.clone()
-			.into(),
+	let (mut event, target_membership, sender, target) = validate_any_membership_event(
+		&services,
+		&body.pdu,
+		&room_version_rules,
+		create_event.event_id().to_owned(),
+		body.room_id.clone(),
+		body.event_id.clone(),
 	)
-	.map_err(|e| err!(Request(InvalidParam("Event has invalid event type: {e}"))))?;
+	.await?;

-	if event_type != StateEventType::RoomMember {
-		return Err!(Request(InvalidParam(
-			"Not allowed to send non-membership state event to knock endpoint.",
-		)));
+	if target_membership != MembershipState::Knock {
+		return Err!(Request(InvalidParam("Invalid membership (expected `knock`)")));
 	}
-
-	let content: RoomMemberEventContent = serde_json::from_value(
-		value
-			.get("content")
-			.ok_or_else(|| err!(Request(InvalidParam("Membership event has no content"))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(InvalidParam("Event has invalid membership content: {e}"))))?;
-
-	if content.membership != MembershipState::Knock {
-		return Err!(Request(InvalidParam(
-			"Not allowed to send a non-knock membership event to knock endpoint."
-		)));
-	}
-
-	// ACL check sender server name
-	let sender: OwnedUserId = serde_json::from_value(
-		value
-			.get("sender")
-			.ok_or_else(|| err!(Request(InvalidParam("Event has no sender user ID."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson("Event sender is not a valid user ID: {e}"))))?;
-
-	services
-		.rooms
-		.event_handler
-		.acl_check(sender.server_name(), &body.room_id)
-		.await?;
-
-	// check if origin server is trying to send for another server
 	if sender.server_name() != body.identity {
-		return Err!(Request(BadJson("Not allowed to knock on behalf of another server/user.")));
+		return Err!(Request(InvalidParam("Sender belongs to a different server")));
+	}
+	if sender != target {
+		return Err!(Request(InvalidParam("Sender does not match state key")));
 	}

-	let state_key: OwnedUserId = serde_json::from_value(
-		value
-			.get("state_key")
-			.ok_or_else(|| err!(Request(InvalidParam("Event does not have a state_key"))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson("Event does not have a valid state_key: {e}"))))?;
+	event.insert("event_id".to_owned(), body.event_id.as_str().into());

-	if state_key != sender {
-		return Err!(Request(InvalidParam("state_key does not match sender user of event.")));
-	}
-
-	let mut event: JsonObject = serde_json::from_str(body.pdu.get())
-		.map_err(|e| err!(Request(InvalidParam("Invalid knock event PDU: {e}"))))?;
-
-	event.insert("event_id".to_owned(), "$placeholder".into());
-
-	let pdu: PduEvent = serde_json::from_value(event.into())
+	let pdu = PduEvent::from_id_val(&body.event_id, event.clone())
 		.map_err(|e| err!(Request(InvalidParam("Invalid knock event PDU: {e}"))))?;

 	let mutex_lock = services
@@ -166,7 +98,7 @@ pub(crate) async fn create_knock_event_v1_route(
 	let pdu_id = services
 		.rooms
 		.event_handler
-		.handle_incoming_pdu(sender.server_name(), &body.room_id, &event_id, value.clone(), true)
+		.handle_incoming_pdu(sender.server_name(), &body.room_id, &body.event_id, event, false)
 		.boxed()
 		.await?
 		.ok_or_else(|| err!(Request(InvalidParam("Could not accept as timeline event."))))?;
@@ -181,7 +113,7 @@ pub(crate) async fn create_knock_event_v1_route(
 	let knock_room_state = services
 		.rooms
 		.state
-		.summary_stripped(&pdu, &body.room_id, &sender)
+		.summary_stripped(&pdu, &body.room_id, &sender, true)
 		.await;

 	Ok(create_knock_event::v1::Response::new(knock_room_state))
@@ -1,18 +1,11 @@
 use axum::extract::State;
-use conduwuit::{Err, Result, err, info, matrix::event::gen_event_id_canonical_json};
-use conduwuit_service::Services;
+use conduwuit::{Err, Result, debug_info, err};
 use futures::FutureExt;
 use ruma::{
-	OwnedRoomId, OwnedUserId, RoomId, ServerName,
-	api::federation::membership::create_leave_event,
-	events::{
-		StateEventType,
-		room::member::{MembershipState, RoomMemberEventContent},
-	},
+	api::federation::membership::create_leave_event, events::room::member::MembershipState,
 };
-use serde_json::value::RawValue as RawJsonValue;

-use crate::Ruma;
+use crate::{Ruma, server::utils::validate_any_membership_event};

 /// # `PUT /_matrix/federation/v2/send_leave/{roomId}/{eventId}`
 ///
@@ -21,17 +14,8 @@ pub(crate) async fn create_leave_event_v2_route(
 	State(services): State<crate::State>,
 	body: Ruma<create_leave_event::v2::Request>,
 ) -> Result<create_leave_event::v2::Response> {
-	create_leave_event(&services, &body.identity, &body.room_id, &body.pdu).await?;
-
-	Ok(create_leave_event::v2::Response::new())
-}
-
-async fn create_leave_event(
-	services: &Services,
-	origin: &ServerName,
-	room_id: &RoomId,
-	pdu: &RawJsonValue,
-) -> Result {
+	let room_id = body.room_id.as_ref();
+	let origin = &body.identity;
 	if !services.rooms.metadata.exists(room_id).await {
 		return Err!(Request(NotFound("Room is unknown to this server.")));
 	}
@@ -42,9 +26,10 @@ async fn create_leave_event(
 		.server_in_room(services.globals.server_name(), room_id)
 		.await
 	{
-		info!(
+		debug_info!(
 			origin = origin.as_str(),
-			"Refusing to serve backfill for room we aren't participating in"
+			room_id = %room_id,
+			"Refusing to send_leave for room we aren't participating in"
 		);
 		return Err!(Request(NotFound("This server is not participating in that room.")));
 	}
@@ -56,91 +41,31 @@ async fn create_leave_event(
 		.acl_check(origin, room_id)
 		.await?;

-	// We do not add the event_id field to the pdu here because of signature and
-	// hashes checks
 	let room_version = services.rooms.state.get_room_version(room_id).await?;
+	let create_event = services
+		.rooms
+		.state_accessor
+		.get_room_create_event(room_id)
+		.await;
 	let room_version_rules = room_version.rules().unwrap();

-	let Ok((event_id, value)) = gen_event_id_canonical_json(pdu, &room_version_rules) else {
-		// Event could not be converted to canonical json
-		return Err!(Request(BadJson("Could not convert event to canonical json.")));
-	};
-
-	let event_room_id: OwnedRoomId = serde_json::from_value(
-		serde_json::to_value(
-			value
-				.get("room_id")
-				.ok_or_else(|| err!(Request(BadJson("Event missing room_id property."))))?,
-		)
-		.expect("CanonicalJson is valid json value"),
+	let (value, membership, sender, target) = validate_any_membership_event(
+		&services,
+		&body.pdu,
+		&room_version_rules,
+		create_event.event_id.clone(),
+		body.room_id.clone(),
+		body.event_id.clone(),
 	)
-	.map_err(|e| err!(Request(BadJson(warn!("room_id field is not a valid room ID: {e}")))))?;
-
-	if event_room_id != room_id {
-		return Err!(Request(BadJson("Event room_id does not match request path room ID.")));
+	.await?;
+	if membership != MembershipState::Leave {
+		return Err!(Request(InvalidParam("Invalid membership (expected `leave`)")));
 	}
-
-	let content: RoomMemberEventContent = serde_json::from_value(
-		value
-			.get("content")
-			.ok_or_else(|| err!(Request(BadJson("Event missing content property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("Event content is empty or invalid: {e}")))))?;
-
-	if content.membership != MembershipState::Leave {
-		return Err!(Request(BadJson(
-			"Not allowed to send a non-leave membership event to leave endpoint."
-		)));
+	if sender.server_name() != body.identity {
+		return Err!(Request(InvalidParam("Sender belongs to a different server")));
 	}
-
-	let event_type: StateEventType = serde_json::from_value(
-		value
-			.get("type")
-			.ok_or_else(|| err!(Request(BadJson("Event missing type property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("Event has invalid state event type: {e}")))))?;
-
-	if event_type != StateEventType::RoomMember {
-		return Err!(Request(BadJson(
-			"Not allowed to send non-membership state event to leave endpoint."
-		)));
-	}
-
-	// ACL check sender server name
-	let sender: OwnedUserId = serde_json::from_value(
-		value
-			.get("sender")
-			.ok_or_else(|| err!(Request(BadJson("Event missing sender property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("sender property is not a valid user ID: {e}")))))?;
-
-	services
-		.rooms
-		.event_handler
-		.acl_check(sender.server_name(), room_id)
-		.await?;
-
-	if sender.server_name() != origin {
-		return Err!(Request(BadJson("Not allowed to leave on behalf of another server/user.")));
-	}
-
-	let state_key: OwnedUserId = serde_json::from_value(
-		value
-			.get("state_key")
-			.ok_or_else(|| err!(Request(BadJson("Event missing state_key property."))))?
-			.clone()
-			.into(),
-	)
-	.map_err(|e| err!(Request(BadJson(warn!("State key is not a valid user ID: {e}")))))?;
-
-	if state_key != sender {
-		return Err!(Request(BadJson("State key does not match sender user.")));
+	if sender != target {
+		return Err!(Request(InvalidParam("Sender does not match state key")));
 	}

 	let mutex_lock = services
@@ -153,7 +78,7 @@ async fn create_leave_event(
 	let pdu_id = services
 		.rooms
 		.event_handler
-		.handle_incoming_pdu(origin, room_id, &event_id, value, true)
+		.handle_incoming_pdu(origin, room_id, &body.event_id, value, false)
 		.boxed()
 		.await?
 		.ok_or_else(|| err!(Request(InvalidParam("Could not accept as timeline event."))))?;
@@ -164,5 +89,7 @@ async fn create_leave_event(
 		.sending
 		.send_pdu_room(room_id, &pdu_id)
 		.boxed()
-		.await
+		.await?;
+
+	Ok(create_leave_event::v2::Response::new())
 }
@@ -1,7 +1,10 @@
-use conduwuit::{Err, Result, is_false};
+use conduwuit::{Err, Result, err, is_false};
 use conduwuit_service::Services;
 use futures::{FutureExt, future::OptionFuture, join};
-use ruma::{EventId, RoomId, ServerName};
+use ruma::{
+	CanonicalJsonObject, EventId, OwnedEventId, OwnedRoomId, OwnedUserId, RoomId, ServerName,
+	UserId, events::room::member::MembershipState, room_version_rules::RoomVersionRules,
+};

 pub(super) struct AccessCheck<'a> {
 	pub(super) services: &'a Services,
@@ -63,3 +66,103 @@ pub(super) async fn assert(&self) -> Result {
 		Ok(())
 	}
 }
+
+/// Performs validation on a membership event that should be run on any event a
+/// remote is trying to send via us.
+///
+/// ## Checks performed
+///
+/// 1. PDU room ID matches request path room ID
+/// 2. PDU event ID matches request path event ID
+/// 3. Signature check
+/// 4. Event type check
+/// 5. `sender` field presence (and parsing)
+/// 6. `state_key` field presence (and parsing)
+/// 7. PDU room format check (PDU check 1)
+///
+/// ## Returns
+///
+/// A resulting tuple of (PDU JSON, target membership state, sender, recipient).
+pub(crate) async fn validate_any_membership_event(
+	services: &crate::State,
+	body: &serde_json::value::RawValue,
+	room_version_rules: &RoomVersionRules,
+	create_event_id: OwnedEventId,
+	expected_room_id: OwnedRoomId,
+	expected_event_id: OwnedEventId,
+) -> Result<(CanonicalJsonObject, MembershipState, OwnedUserId, OwnedUserId)> {
+	let (template_room_id, template_event_id, pdu) = services
+		.rooms
+		.event_handler
+		.parse_incoming_pdu(body, Some(room_version_rules))
+		.await
+		.map_err(|e| err!(Request(BadJson("Invalid membership PDU: {e}"))))?;
+
+	if template_room_id != expected_room_id {
+		return Err!(Request(InvalidParam("Membership event does not belong to requested room")));
+	}
+	if template_event_id != expected_event_id {
+		return Err!(Request(InvalidParam(debug_warn!(
+			%template_event_id,
+			%expected_event_id,
+			"Membership event ID does not match provided event ID"
+		))));
+	}
+
+	services
+		.server_keys
+		.verify_event(&pdu, room_version_rules)
+		.await
+		.map_err(|e| {
+			err!(Request(InvalidParam("Signature verification failed on membership event: {e}")))
+		})?;
+
+	// Ensure this is a membership event
+	if pdu
+		.get("type")
+		.expect("event must have a type")
+		.as_str()
+		.expect("type must be a string")
+		!= "m.room.member"
+	{
+		return Err!(Request(BadJson(
+			"Not allowed to send non-membership event to this endpoint"
+		)));
+	}
+	let membership = pdu
+		.get("content")
+		.ok_or_else(|| err!(Request(BadJson("Event missing content property"))))?
+		.as_object()
+		.ok_or_else(|| err!(Request(BadJson("Event content is not an object"))))?
+		.get("membership")
+		.ok_or_else(|| err!(Request(BadJson("Event missing membership property"))))?
+		.as_str()
+		.ok_or_else(|| err!(Request(BadJson("Event is not a string"))))?
+		.to_owned();
+
+	let sender_user = pdu
+		.get("sender")
+		.and_then(|v| v.as_str())
+		.map(UserId::parse)
+		.and_then(Result::ok)
+		.ok_or_else(|| err!(Request(InvalidParam("Invalid sender property"))))?;
+	let recipient_user = pdu
+		.get("state_key")
+		.and_then(|v| v.as_str())
+		.map(UserId::parse)
+		.and_then(Result::ok)
+		.ok_or_else(|| err!(Request(InvalidParam("Invalid state_key property"))))?;
+
+	// Do a quick format check. The spec doesn't suggest this, but it's probably
+	// a good idea nonetheless.
+	service::rooms::event_handler::Service::pdu_format_check_1(
+		&pdu,
+		room_version_rules,
+		&create_event_id,
+	)
+	.map_err(|e| {
+		err!(Request(InvalidParam("Membership event violates the room event format: {e}")))
+	})?;
+
+	Ok((pdu, membership.into(), sender_user, recipient_user))
+}
@@ -2442,6 +2442,7 @@ pub struct OauthConfig {
 	///   legacy authentication will be unable to log in.
 	///
 	/// default: "hybrid"
+	#[serde(default)]
 	compatibility_mode: OAuthMode,

 	/// display: hidden
@@ -149,6 +149,14 @@ macro_rules! err_log {
 #[macro_export]
 #[collapse_debuginfo(yes)]
 macro_rules! err_lev {
+	(debug_info) => {
+		if $crate::debug::logging() {
+			$crate::tracing::Level::INFO
+		} else {
+			$crate::tracing::Level::DEBUG
+		}
+	};
+
 	(debug_warn) => {
 		if $crate::debug::logging() {
 			$crate::tracing::Level::WARN
@@ -219,7 +219,7 @@ fn configure_output_err(mut output: MadSkin) -> MadSkin {
 	use termimad::{Alignment, CompoundStyle, LineStyle, crossterm::style::Color};

 	let code_style = CompoundStyle::with_fgbg(Color::AnsiValue(196), Color::AnsiValue(234));
-	output.inline_code = code_style.clone();
+	output.inline_code = code_style;
 	output.code_block = LineStyle {
 		left_margin: 0,
 		right_margin: 0,
@@ -234,7 +234,7 @@ fn configure_output(mut output: MadSkin) -> MadSkin {
 	use termimad::{Alignment, CompoundStyle, LineStyle, crossterm::style::Color};

 	let code_style = CompoundStyle::with_fgbg(Color::AnsiValue(40), Color::AnsiValue(234));
-	output.inline_code = code_style.clone();
+	output.inline_code = code_style;
 	output.code_block = LineStyle {
 		left_margin: 0,
 		right_margin: 0,
@@ -829,7 +829,7 @@ async fn fix_local_invite_state(services: &Services) -> Result {
 				&& services.globals.user_is_local(&membership_event.sender) {

 				// build and save stripped state for their invite in the database
-				let stripped_state = services.rooms.state.summary_stripped(&membership_event, &room_id, &user_id).await;
+				let stripped_state = services.rooms.state.summary_stripped(&membership_event, &room_id, &user_id, false).await;
 				userroomid_invitestate.put((&user_id, &room_id), Json(stripped_state));
 				fixed = fixed.saturating_add(1);
 			}
@@ -882,7 +882,7 @@ async fn split_userid_password(services: &Services) -> Result {
 	drop(cork);
 	info!(?remote_users, "Split userid_password.");

-	db["global"].insert(FIXED_LOCAL_INVITE_STATE_MARKER, []);
+	db["global"].insert(SPLIT_USERID_PASSWORD, []);
 	db.db.sort()?;
 	Ok(())
 }
@@ -895,5 +895,7 @@ async fn obliterate_roomsynctoken_shortstatehash_with_extreme_prejudice(

 	info!("Cleared roomsynctoken_shortstatehash.");

+	services.db["global"].insert(DROP_ROOMSYNCTOKEN_SHORTSTATEHASH, []);
+
 	Ok(())
 }
@@ -132,6 +132,8 @@ pub enum ApplicationType {
 #[serde(rename_all = "snake_case")]
 pub enum GrantType {
 	AuthorizationCode,
+	#[serde(rename = "urn:ietf:params:oauth:grant-type:device_code")]
+	DeviceCode,
 	RefreshToken,
 }

@@ -13,6 +13,7 @@
 use url::Url;

 use super::client_metadata::ResponseType;
+use crate::oauth::client_metadata::GrantType;

 #[derive(Debug, Clone, Deserialize, Serialize)]
 pub struct AuthorizationCodeQuery {
@@ -29,6 +30,33 @@ pub struct AuthorizationCodeQuery {
 	pub prompt: Option<Prompt>,
 }

+#[derive(Deserialize, Serialize)]
+pub struct AuthorizationCodeResponse {
+	pub state: String,
+	pub code: String,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct DeviceCodeRequest {
+	pub client_id: String,
+	pub scope: RawScopes,
+}
+
+#[derive(Deserialize, Serialize)]
+pub struct DeviceCodeResponse {
+	pub device_code: String,
+	pub user_code: String,
+	pub verification_uri: Url,
+	#[serde(skip_serializing_if = "Option::is_none")]
+	pub verification_uri_complete: Option<Url>,
+	pub expires_in: u64,
+}
+
+#[derive(Debug, Clone, Deserialize, Serialize)]
+pub struct DeviceCodeVerifyQuery {
+	pub user_code: Option<String>,
+}
+
 #[derive(Debug, Clone, Default, Deserialize, Serialize)]
 #[serde(rename_all = "snake_case")]
 #[non_exhaustive]
@@ -126,19 +154,29 @@ pub struct OAuthError {

 impl OAuthError {
 	#[must_use]
-	pub const fn invalid_request(error_description: &'static str) -> Self {
+	pub fn new(error: ErrorCode, error_description: String) -> Self {
 		Self {
-			error: ErrorCode::InvalidRequest,
+			error,
+			error_description: Cow::Owned(error_description),
+		}
+	}
+
+	#[must_use]
+	pub const fn new_static(error: ErrorCode, error_description: &'static str) -> Self {
+		Self {
+			error,
 			error_description: Cow::Borrowed(error_description),
 		}
 	}

+	#[must_use]
+	pub const fn invalid_request(error_description: &'static str) -> Self {
+		Self::new_static(ErrorCode::InvalidRequest, error_description)
+	}
+
 	#[must_use]
 	pub const fn invalid_grant(error_description: &'static str) -> Self {
-		Self {
-			error: ErrorCode::InvalidGrant,
-			error_description: Cow::Borrowed(error_description),
-		}
+		Self::new_static(ErrorCode::InvalidGrant, error_description)
 	}
 }

@@ -157,36 +195,43 @@ pub enum ErrorCode {
 	AccessDenied,
 	InvalidScope,
 	InvalidGrant,
+	InvalidClient,
 	InvalidClientMetadata,
+	AuthorizationPending,
+	ExpiredToken,
 }

-#[derive(Serialize, Deserialize)]
-pub struct AuthorizationCodeResponse {
-	pub state: String,
-	pub code: String,
+#[derive(Deserialize)]
+pub struct TokenRequest {
+	pub client_id: String,
+	#[serde(flatten)]
+	pub request: TokenRequestType,
 }

 #[derive(Deserialize)]
 #[serde(tag = "grant_type", rename_all = "snake_case")]
-pub enum TokenRequest {
+pub enum TokenRequestType {
 	AuthorizationCode {
 		code: String,
 		redirect_uri: Url,
-		client_id: String,
 		code_verifier: String,
 	},
+	#[serde(rename = "urn:ietf:params:oauth:grant-type:device_code")]
+	DeviceCode {
+		device_code: String,
+	},
 	RefreshToken {
-		client_id: String,
 		refresh_token: String,
 	},
 }

-impl TokenRequest {
+impl TokenRequestType {
 	#[must_use]
-	pub fn client_id(&self) -> &str {
+	pub fn grant_type(&self) -> GrantType {
 		match self {
-			| Self::AuthorizationCode { client_id, .. }
-			| Self::RefreshToken { client_id, .. } => client_id,
+			| Self::AuthorizationCode { .. } => GrantType::AuthorizationCode,
+			| Self::DeviceCode { .. } => GrantType::DeviceCode,
+			| Self::RefreshToken { .. } => GrantType::RefreshToken,
 		}
 	}
 }
@@ -12,17 +12,19 @@
 use database::{Deserialized, Json, Map};
 use itertools::Itertools;
 use lru_cache::LruCache;
+use rand::distr::{Distribution, slice::Choose};
 use ruma::{DeviceId, OwnedDeviceId, OwnedUserId, UserId};
 use serde::{Deserialize, Serialize};
 use url::Url;

 use crate::{
-	Dep,
+	Dep, config,
 	oauth::{
 		client_metadata::{ApplicationType, ClientMetadata, ResponseType},
 		grant::{
-			AuthorizationCodeQuery, AuthorizationCodeResponse, CodeChallengeMethod, ErrorCode,
-			OAuthError, ResponseMode, Scope, TokenRequest, TokenResponse, TokenType,
+			AuthorizationCodeQuery, AuthorizationCodeResponse, CodeChallengeMethod,
+			DeviceCodeRequest, DeviceCodeResponse, ErrorCode, OAuthError, ResponseMode, Scope,
+			TokenRequest, TokenRequestType, TokenResponse, TokenType,
 		},
 	},
 	users,
@@ -35,7 +37,8 @@ pub struct Service {
 	services: Services,
 	db: Data,
 	tickets: Mutex<HashMap<String, HashMap<OAuthTicket, SystemTime>>>,
-	pending_code_grants: tokio::sync::Mutex<LruCache<String, PendingCodeGrant>>,
+	pending_auth_code_grants: tokio::sync::Mutex<LruCache<String, PendingAuthCodeGrant>>,
+	pending_device_code_grants: tokio::sync::Mutex<LruCache<String, PendingDeviceCodeGrant>>,
 }

 struct Data {
@@ -46,6 +49,7 @@ struct Data {

 struct Services {
 	users: Dep<users::Service>,
+	config: Dep<config::Service>,
 }

 #[derive(Debug, Deserialize, Serialize)]
@@ -62,7 +66,7 @@ struct RefreshTokenInfo {
 	device_id: OwnedDeviceId,
 }

-struct PendingCodeGrant {
+struct PendingAuthCodeGrant {
 	authorizing_user: OwnedUserId,
 	requested_scopes: BTreeSet<Scope>,
 	client_name: Option<String>,
@@ -72,12 +76,8 @@ struct PendingCodeGrant {
 	requested_at: SystemTime,
 }

-impl PendingCodeGrant {
+impl PendingAuthCodeGrant {
 	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 {
@@ -90,6 +90,43 @@ pub(crate) fn is_valid_for(&self, client_id: &str) -> bool {
 	}
 }

+struct PendingDeviceCodeGrant {
+	state: DeviceCodeGrantState,
+	requested_scopes: BTreeSet<Scope>,
+	client_name: Option<String>,
+	client_id: String,
+	requested_at: SystemTime,
+}
+
+enum DeviceCodeGrantState {
+	Unverified {
+		user_code: String,
+	},
+	Verified {
+		authorizing_user: OwnedUserId,
+	},
+}
+
+impl PendingDeviceCodeGrant {
+	const MAX_AGE: Duration = Duration::from_mins(1);
+
+	#[must_use]
+	pub(crate) fn is_valid_for(&self, client_id: &str) -> bool {
+		let now = SystemTime::now();
+
+		self.client_id == client_id
+			&& now
+				.duration_since(self.requested_at)
+				.is_ok_and(|age| age < Self::MAX_AGE)
+	}
+}
+
+pub struct DeviceCodeGrantInfo {
+	pub device_code: String,
+	pub client_metadata: ClientMetadata,
+	pub requested_scopes: BTreeSet<Scope>,
+}
+
 /// A time-limited grant for a client to perform some sensitive action.
 #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
 pub enum OAuthTicket {
@@ -112,6 +149,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 		Ok(Arc::new(Self {
 			services: Services {
 				users: args.depend::<users::Service>("users"),
+				config: args.depend::<config::Service>("config"),
 			},
 			db: Data {
 				clientid_clientmetadata: args.db["clientid_clientmetadata"].clone(),
@@ -119,8 +157,11 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 				refreshtoken_refreshtokeninfo: args.db["refreshtoken_refreshtokeninfo"].clone(),
 			},
 			tickets: Mutex::default(),
-			pending_code_grants: tokio::sync::Mutex::new(LruCache::new(
-				Self::MAX_PENDING_CODE_GRANTS,
+			pending_auth_code_grants: tokio::sync::Mutex::new(LruCache::new(
+				Self::MAX_PENDING_GRANTS,
+			)),
+			pending_device_code_grants: tokio::sync::Mutex::new(LruCache::new(
+				Self::MAX_PENDING_GRANTS,
 			)),
 		}))
 	}
@@ -133,11 +174,21 @@ impl Service {
 	// 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 MAX_PENDING_GRANTS: usize = 100;
 	const RANDOM_TOKEN_LENGTH: usize = 32;
+	const USER_CODE_CHARACTERS: &[char] = &['0', '1', '2', '3', '4', '5', '6', '7', '8', '9'];
+	const USER_CODE_LENGTH: usize = 6;

 	fn generate_token() -> String { utils::random_string(Self::RANDOM_TOKEN_LENGTH) }

+	fn generate_user_code() -> String {
+		Choose::new(Self::USER_CODE_CHARACTERS)
+			.unwrap()
+			.sample_iter(&mut rand::rng())
+			.take(Self::USER_CODE_LENGTH)
+			.collect()
+	}
+
 	pub async fn register_client(&self, metadata: &ClientMetadata) -> Result<String, OAuthError> {
 		metadata.validate().map_err(|error| OAuthError {
 			error: ErrorCode::InvalidClientMetadata,
@@ -231,14 +282,14 @@ pub async fn request_authorization_code(
 			| ResponseMode::Query => '?',
 		};

-		let code = PendingCodeGrant::generate_code();
+		let code = Self::generate_token();

 		info!(
 			client_id = &query.client_id,
 			client_name = &client_metadata.client_name,
 			?requested_scopes,
 			?authorizing_user,
-			"Issuing oauth authorization code"
+			"Issuing OAuth authorization code"
 		);

 		let redirect_uri = format!(
@@ -252,7 +303,7 @@ pub async fn request_authorization_code(
 			.unwrap(),
 		);

-		let pending_grant = PendingCodeGrant {
+		let pending_grant = PendingAuthCodeGrant {
 			authorizing_user,
 			requested_scopes,
 			client_name: client_metadata.client_name,
@@ -262,7 +313,7 @@ pub async fn request_authorization_code(
 			requested_at: SystemTime::now(),
 		};

-		self.pending_code_grants
+		self.pending_auth_code_grants
 			.lock()
 			.await
 			.insert(code, pending_grant);
@@ -270,15 +321,129 @@ pub async fn request_authorization_code(
 		Ok(redirect_uri)
 	}

+	pub async fn request_device_code(
+		&self,
+		query: DeviceCodeRequest,
+	) -> Result<DeviceCodeResponse, OAuthError> {
+		let Some(client_metadata) = self.get_client_metadata(&query.client_id).await else {
+			return Err(OAuthError::new_static(ErrorCode::InvalidClient, "Invalid client ID"));
+		};
+
+		let requested_scopes = query
+			.scope
+			.to_scopes()
+			.map_err(|err| OAuthError::new(ErrorCode::InvalidGrant, err))?;
+
+		let device_code = Self::generate_token();
+		let user_code = Self::generate_user_code();
+
+		let verification_uri = self
+			.services
+			.config
+			.get_client_domain()
+			.join(&format!("{}/oauth2/grant/device_code", conduwuit::ROUTE_PREFIX))
+			.unwrap();
+
+		let mut verification_uri_complete = verification_uri.clone();
+		verification_uri_complete
+			.query_pairs_mut()
+			.append_pair("user_code", &user_code);
+
+		info!(
+			client_id = &query.client_id,
+			client_name = &client_metadata.client_name,
+			?requested_scopes,
+			"Issuing OAuth device code"
+		);
+
+		let pending_grant = PendingDeviceCodeGrant {
+			state: DeviceCodeGrantState::Unverified { user_code: user_code.clone() },
+			requested_scopes,
+			client_name: client_metadata.client_name,
+			client_id: query.client_id,
+			requested_at: SystemTime::now(),
+		};
+
+		self.pending_device_code_grants
+			.lock()
+			.await
+			.insert(device_code.clone(), pending_grant);
+
+		Ok(DeviceCodeResponse {
+			device_code,
+			user_code,
+			verification_uri,
+			verification_uri_complete: Some(verification_uri_complete),
+			expires_in: PendingDeviceCodeGrant::MAX_AGE.as_secs(),
+		})
+	}
+
+	pub async fn grant_info_for_user_code(
+		&self,
+		supplied_user_code: &str,
+	) -> Option<DeviceCodeGrantInfo> {
+		let pending_grants = self.pending_device_code_grants.lock().await;
+
+		let (device_code, grant) = pending_grants
+			.iter()
+			.find(|(_, grant)| {
+				matches!(&grant.state, DeviceCodeGrantState::Unverified { user_code } if user_code == supplied_user_code)
+			})?;
+
+		let client_metadata = self
+			.get_client_metadata(&grant.client_id)
+			.await
+			.expect("client should exist");
+
+		Some(DeviceCodeGrantInfo {
+			device_code: device_code.clone(),
+			client_metadata,
+			requested_scopes: grant.requested_scopes.clone(),
+		})
+	}
+
+	pub async fn validate_device_code(
+		&self,
+		authorizing_user: OwnedUserId,
+		device_code: &str,
+	) -> Result<(), String> {
+		let mut pending_grants = self.pending_device_code_grants.lock().await;
+
+		let Some(pending_grant) = pending_grants.get_mut(device_code) else {
+			return Err("Invalid device code".to_owned());
+		};
+
+		match &mut pending_grant.state {
+			| state @ DeviceCodeGrantState::Unverified { .. } => {
+				*state = DeviceCodeGrantState::Verified { authorizing_user };
+
+				Ok(())
+			},
+			| DeviceCodeGrantState::Verified {
+				authorizing_user: previous_authorizing_user,
+			} =>
+				if *previous_authorizing_user == authorizing_user {
+					Ok(())
+				} else {
+					Err("Device code is already verified".to_owned())
+				},
+		}
+	}
+
 	pub async fn issue_token(&self, request: TokenRequest) -> Result<TokenResponse, OAuthError> {
+		let TokenRequest { client_id, request } = request;
+
+		let Some(client_metadata) = self.get_client_metadata(&client_id).await else {
+			return Err(OAuthError::new_static(ErrorCode::InvalidClient, "Invalid client ID"));
+		};
+
+		if !client_metadata.grant_types.contains(&request.grant_type()) {
+			return Err(OAuthError::invalid_grant("Client cannot request this grant type"));
+		}
+
 		match request {
-			| TokenRequest::AuthorizationCode {
-				code,
-				redirect_uri,
-				client_id,
-				code_verifier,
-			} => {
-				let mut pending_grants = self.pending_code_grants.lock().await;
+			| TokenRequestType::AuthorizationCode { code, redirect_uri, code_verifier } => {
+				let mut pending_grants = self.pending_auth_code_grants.lock().await;

 				let Some(pending_grant) = pending_grants
 					.remove(&code)
@@ -305,7 +470,39 @@ pub async fn issue_token(&self, request: TokenRequest) -> Result<TokenResponse,
 				)
 				.await
 			},
-			| TokenRequest::RefreshToken { client_id, refresh_token } =>
+			| TokenRequestType::DeviceCode { device_code } => {
+				let mut pending_grants = self.pending_device_code_grants.lock().await;
+
+				let Some(pending_grant) = pending_grants
+					.remove(&device_code)
+					.filter(|grant| grant.is_valid_for(&client_id))
+				else {
+					return Err(OAuthError::new_static(
+						ErrorCode::ExpiredToken,
+						"Invalid device code",
+					));
+				};
+
+				match &pending_grant.state {
+					| DeviceCodeGrantState::Unverified { .. } => {
+						pending_grants.insert(device_code, pending_grant);
+
+						Err(OAuthError::new_static(
+							ErrorCode::AuthorizationPending,
+							"Authorization is pending",
+						))
+					},
+					| DeviceCodeGrantState::Verified { authorizing_user } =>
+						self.create_session(
+							authorizing_user.to_owned(),
+							pending_grant.requested_scopes,
+							pending_grant.client_name,
+							client_id,
+						)
+						.await,
+				}
+			},
+			| TokenRequestType::RefreshToken { refresh_token } =>
 				self.refresh_session(client_id, refresh_token).await,
 		}
 	}
@@ -364,11 +561,10 @@ async fn create_session(
 			.await
 			.is_ok()
 		{
-			return Err(OAuthError {
-				error: ErrorCode::InvalidScope,
-				error_description: "A device with the supplied ID already exists for this user"
-					.into(),
-			});
+			return Err(OAuthError::new_static(
+				ErrorCode::InvalidScope,
+				"A device with the supplied ID already exists for this user",
+			));
 		}

 		self.services
@@ -115,6 +115,21 @@ pub enum SessionCompletionStatus {
 	Complete(OwnedUserId),
 }

+pub enum ClaimedLocalUser {
+	/// The claim refers to an existing user.
+	Existing(OwnedUserId),
+	/// The claim refers to a new user ID which should be registered.
+	New(OwnedUserId),
+}
+
+impl ClaimedLocalUser {
+	fn into_user_id(self) -> OwnedUserId {
+		match self {
+			| Self::Existing(user_id) | Self::New(user_id) => user_id,
+		}
+	}
+}
+
 #[async_trait]
 impl crate::Service for Service {
 	fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
@@ -136,6 +151,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
                    config: config.clone(),
 					client_secret: if let Some(client_secret_file) = &config.client_secret_file {
 						std::fs::read_to_string(client_secret_file)
+							.map(|client_secret| client_secret.trim().to_owned())
 							.map(ClientSecret::new)
 							.map_err(|err| err!("Failed to read OIDC client secret file: {err}"))?
 					} else if let Some(client_secret) = &config.client_secret {
@@ -303,7 +319,7 @@ pub async fn complete_session(
 			.expect("claims should be an object")
 			.to_owned();

-		debug!(?all_claims);
+		debug!(?all_claims, "Got claims from the identity provider");

 		let subject = claims.subject().as_str();

@@ -326,14 +342,13 @@ pub async fn complete_session(
 			.get(&config.preferred_username_claim)
 			.and_then(|claim| claim.as_str())
 		{
-			self.services
-				.users
-				.determine_registration_user_id(Some(preferred_username.to_owned()), None, None)
+			self.identify_claimed_local_user(preferred_username)
 				.await
+				.map(ClaimedLocalUser::into_user_id)
 				.map_err(|err| {
 					error!("Preferred username claim is not a valid localpart: {err}");
-					"Your preferred username is not a valid Matrix user ID localpart. Contact \
-					 your homeserver's administrator."
+					"Your preferred username could not be converted to a valid Matrix user ID. \
+					 Contact your homeserver's administrator."
 				})?
 		} else {
 			error!("Preferred username claim was not present or was not a string");
@@ -482,4 +497,22 @@ pub fn link_user(&self, user_id: &UserId, subject: &str) {
 	}

 	pub fn unlink_user(&self, subject: &str) { self.db.openidsubject_localpart.remove(subject); }
+
+	/// Determine what user ID a localpart claim refers to.
+	pub async fn identify_claimed_local_user(&self, claim: &str) -> Result<ClaimedLocalUser> {
+		if let Ok(user_id) =
+			UserId::parse(format!("@{}:{}", claim, self.services.globals.server_name()))
+			&& self.services.users.status(&user_id).await.is_active()
+		{
+			Ok(ClaimedLocalUser::Existing(user_id))
+		} else {
+			let user_id = self
+				.services
+				.users
+				.determine_registration_user_id(Some(claim.to_owned()), None, None)
+				.await?;
+
+			Ok(ClaimedLocalUser::New(user_id))
+		}
+	}
 }
@@ -14,6 +14,7 @@ pub async fn acl_check(&self, server_name: &ServerName, room_id: &RoomId) -> Res
 			.await
 			.map(|c: RoomServerAclEventContent| c)
 		else {
+			trace!("Room has no ACL, allowing");
 			return Ok(());
 		};

@@ -1,5 +1,6 @@
 use std::{
 	collections::{HashMap, HashSet, VecDeque},
+	fmt::{Display, Formatter},
 	time::Instant,
 };

@@ -33,6 +34,20 @@ pub enum DagBuilderTree {
 	AuthEvents,
 }

+impl DagBuilderTree {
+	#[must_use]
+	pub fn as_str(&self) -> &str {
+		match self {
+			| Self::AuthEvents => "auth_events",
+			| Self::PrevEvents => "prev_events",
+		}
+	}
+}
+
+impl Display for DagBuilderTree {
+	fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result { f.write_str(self.as_str()) }
+}
+
 /// Attempts to build a localised directed acyclic graph out of the given PDUs,
 /// returning them in a topologically sorted order.
 ///
@@ -42,23 +57,22 @@ pub enum DagBuilderTree {
 /// not account for power levels or other tie breaks.
 #[allow(clippy::implicit_hasher)]
 pub async fn build_local_dag(
-	pdu_map: &HashMap<OwnedEventId, &CanonicalJsonObject>,
+	pdu_map: &HashMap<OwnedEventId, CanonicalJsonObject>,
 	tree: DagBuilderTree,
 ) -> Result<Vec<OwnedEventId>> {
-	debug_assert!(pdu_map.len() >= 2, "needless call to build_local_dag with less than 2 PDUs");
+	if pdu_map.len() <= 1 {
+		return Ok(pdu_map.keys().cloned().collect());
+	}
+
 	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 tree = match tree {
-		| DagBuilderTree::AuthEvents => "auth_events",
-		| DagBuilderTree::PrevEvents => "prev_events",
-	};

 	for (event_id, value) in pdu_map {
 		// Parse all prev events as event IDs - if they are missing, return an error (we
 		// can't sanely continue in this case), otherwise skip invalid prev events.
 		let prev_events = value
-			.get(tree)
+			.get(tree.as_str())
 			.and_then(CanonicalJsonValue::as_array)
 			.ok_or_else(|| err!(Request(BadJson("event JSON for {event_id} is missing {tree}"))))?
 			.iter()
@@ -227,7 +241,7 @@ pub async fn get_missing_events(

 			latest_events.clear();
 			for raw_event in response.events {
-				let (_, event_id, pdu_json) = self.parse_incoming_pdu(&raw_event).await?;
+				let (_, event_id, pdu_json) = self.parse_incoming_pdu(&raw_event, None).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}")))
 				})?;
@@ -370,8 +384,8 @@ async fn fetch_event_via(
 			.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)
+		let (_, calculated_event_id, value) = self
+			.parse_incoming_pdu(&res.pdu, Some(room_version_rules))
 			.await?;

 		if calculated_event_id != event_id {
@@ -538,11 +552,7 @@ pub(super) async fn fetch_and_handle_auth_events<Pdu>(
 			}
 		}

-		let refmap: HashMap<OwnedEventId, &CanonicalJsonObject> = discovered_events
-			.iter()
-			.map(|(id, data)| (id.clone(), data))
-			.collect();
-		let seeded_ordered = build_local_dag(&refmap, DagBuilderTree::AuthEvents)
+		let seeded_ordered = build_local_dag(&discovered_events, DagBuilderTree::AuthEvents)
 			.await
 			.expect("failed to build local DAG");
 		let mut pdus = HashMap::with_capacity(seeded_ordered.len());
@@ -1,9 +1,8 @@
 use std::collections::{HashMap, hash_map};

-use conduwuit::{Err, Event, EventTypeExt, PduEvent, Result, err};
+use conduwuit::{Err, Event, EventTypeExt, PduEvent, Result, err, warn};
 use ruma::{
-	CanonicalJsonObject, OwnedEventId, ServerName,
-	api::federation::authorization::get_event_authorization,
+	OwnedEventId, ServerName, api::federation::authorization::get_event_authorization,
 	room_version_rules::RoomVersionRules,
 };
 use tokio::join;
@@ -49,17 +48,52 @@ pub(super) async fn fetch_and_persist_event_auth<Pdu>(
 		let mut auth_chain_map = HashMap::with_capacity(event_auth.auth_chain.len());

 		for auth_pdu_json in event_auth.auth_chain {
-			let (auth_event_room_id, auth_event_id, auth_pdu_json) =
-				self.parse_incoming_pdu(&auth_pdu_json).await?;
+			let (auth_event_room_id, auth_event_id, auth_pdu_json) = match self
+				.parse_incoming_pdu(&auth_pdu_json, Some(room_version_rules))
+				.await
+			{
+				| Ok(parsed) => parsed,
+				| Err(e) => {
+					warn!(error=?e, "Dropping auth chain event as it could not be parsed");
+					continue;
+				},
+			};
+			if let Err(e) = Self::pdu_format_check_1(
+				&auth_pdu_json,
+				room_version_rules,
+				create_event.event_id(),
+			) {
+				// drop this PDU
+				warn!(%auth_event_id, error=?e, "Dropping auth chain event as it violates the room event format");
+				continue;
+			}
+			let auth_pdu_json = match self
+				.signature_hash_check_2_3(auth_pdu_json, room_version_rules)
+				.await
+			{
+				| Ok(pdu_json) => pdu_json,
+				| Err(e) => {
+					// drop this PDU
+					warn!(
+						%auth_event_id,
+						error=?e,
+						"Dropping auth chain event as it has an invalid signature"
+					);
+					continue;
+				},
+			};
+
+			// PDU check 4 is done when we've finished aggregating
 			if auth_event_room_id != incoming_event.room_id_or_hash() {
 				return Err!(Request(Forbidden(
-					"Auth event {auth_event_id} is in {auth_event_room_id}, not {}.",
+					"Auth chain event {auth_event_id} is in {auth_event_room_id}, not {}.",
 					incoming_event.room_id_or_hash()
 				)));
 			}
 			let auth_pdu = PduEvent::from_id_val(&auth_event_id, auth_pdu_json).map_err(|e| {
 				err!(Request(BadJson("Invalid PDU {auth_event_id} in auth chain: {e}")))
 			})?;
+
 			if auth_pdu.state_key().is_none() {
 				return Err!(Request(BadJson(
 					"Invalid PDU {auth_event_id} in auth_chain: not a state event"
@@ -97,17 +131,11 @@ async fn authorise_remote_auth_chain<Pdu>(
 	where
 		Pdu: Event + Send + Sync,
 	{
-		// TODO(nex): build_local_dag's signature needs changing because all callsites
-		// seem to do this refmap hack.
 		let pdu_objects = auth_chain_map
 			.iter()
-			.map(|(event_id, pdu)| (event_id, pdu.to_canonical_object()))
+			.map(|(event_id, pdu)| (event_id.clone(), pdu.to_canonical_object()))
 			.collect::<HashMap<_, _>>();
-		let refmap: HashMap<OwnedEventId, &CanonicalJsonObject> = pdu_objects
-			.iter()
-			.map(|(id, data)| ((*id).to_owned(), data))
-			.collect();
-		let auth_chain_topo = build_local_dag(&refmap, DagBuilderTree::AuthEvents)
+		let auth_chain_topo = build_local_dag(&pdu_objects, DagBuilderTree::AuthEvents)
 			.await?
 			.into_iter()
 			.map(|event_id| (event_id.clone(), auth_chain_map.get(&event_id).unwrap().to_owned()))
@@ -127,6 +155,12 @@ async fn authorise_remote_auth_chain<Pdu>(
 				continue;
 			}

+			// IMPORTANT: We can't use the handy dandy `handle_outlier_pdu` function here
+			// because it may then try to fetch missing auth events, resulting in deep
+			// recursion. We will do the minimum required steps to validate the PDU here.
+			// Checks 1-3 were already done before this function is called, so we only need
+			// to do check 4.
+
 			let mut auth_events_by_key: HashMap<_, _> =
 				HashMap::with_capacity(pdu.auth_events.len());

@@ -150,24 +184,21 @@ async fn authorise_remote_auth_chain<Pdu>(
 					},
 					| hash_map::Entry::Occupied(_) => {
 						// Duplicate auth events by key are not allowed.
-						self.services
-							.pdu_metadata
-							.mark_event_rejected(auth_event_id);
-						self.services.pdu_metadata.mark_event_rejected(&event_id);
+						self.reject_and_persist(&event_id, &pdu.to_canonical_object());
 						continue 'outer;
 					},
 				}
 			}
 			if !self
-				.is_event_self_authorised(
+				.auth_state_check_4(
 					&pdu,
 					room_version_rules,
 					create_event.as_pdu(),
 					&auth_events_by_key,
 				)
-				.await
+				.await?
 			{
-				self.services.pdu_metadata.mark_event_rejected(&event_id);
+				self.reject_and_persist(&event_id, &pdu.to_canonical_object());
 			}
 		}

@@ -5,13 +5,13 @@
 	utils::{BoolExt, IterStream, stream::BroadbandExt},
 };
 use futures::StreamExt;
-use ruma::{CanonicalJsonObject, MilliSecondsSinceUnixEpoch, OwnedEventId, RoomId, ServerName};
+use ruma::{MilliSecondsSinceUnixEpoch, RoomId, ServerName};

 use crate::rooms::event_handler::{build_local_dag, fetch_and_handle_outliers::DagBuilderTree};

 impl super::Service {
 	/// Fetches any missing prev_events for this event and persists them before
-	/// returning.
+	/// returning. The caller is responsible for then handling the incoming PDU.
 	pub(super) async fn fetch_prevs(
 		&self,
 		room_id: &RoomId,
@@ -84,13 +84,7 @@ pub(super) async fn fetch_prevs(
 			})
 			.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, DagBuilderTree::PrevEvents).await?
-		};
+		let to_persist = build_local_dag(&mapped, DagBuilderTree::PrevEvents).await?;

 		let job_start = Instant::now();
 		trace!("Starting to persist {} prev events", to_persist.len());
@@ -314,7 +314,7 @@ pub(super) async fn fetch_full_state(
 			.iter()
 			.stream()
 			.broad_filter_map(|raw_event_json| async {
-				if let Some(parsed) = self.parse_incoming_pdu(raw_event_json).await.ok()
+				if let Some(parsed) = self.parse_incoming_pdu(raw_event_json, None).await.ok()
 					&& parsed.0 == room_id
 				{
 					Some(parsed)
@@ -351,7 +351,7 @@ pub(super) async fn fetch_full_state(
 			.iter()
 			.stream()
 			.broad_filter_map(|raw_event_json| async {
-				if let Some(parsed) = self.parse_incoming_pdu(raw_event_json).await.ok()
+				if let Some(parsed) = self.parse_incoming_pdu(raw_event_json, None).await.ok()
 					&& parsed.0 == room_id
 				{
 					Some(parsed)
@@ -4,46 +4,37 @@
 };

 use conduwuit::{
-	Err, Event, Result, debug, debug_error, debug_warn, defer, err, error, info,
-	matrix::PartialPdu, result::DebugInspect, trace, utils::time::jitter, warn,
+	Err, Event, Result, debug, debug_error, debug_warn, defer, matrix::PartialPdu, trace,
+	utils::time::jitter,
 };
-use futures::{
-	FutureExt, StreamExt,
-	future::{OptionFuture, try_join4},
-};
-use ruma::{CanonicalJsonValue, EventId, OwnedUserId, RoomId, ServerName, UserId};
+use futures::{FutureExt, StreamExt, future::try_join3};
+use ruma::{CanonicalJsonValue, EventId, RoomId, ServerName, UserId};
 use tokio::sync::mpsc;

-use crate::rooms::timeline::{RawPduId, pdu_fits};
+use crate::rooms::timeline::RawPduId;

 impl super::Service {
-	/// When receiving an event one needs to:
-	/// 0. Check the server is in the room
-	/// 1. Skip the PDU if we already know about it
-	/// 1.1. Remove unsigned field
-	/// 2. Check signatures, otherwise drop
-	/// 3. Check content hash, redact if doesn't match
-	/// 4. Fetch any missing auth events doing all checks listed here starting
-	///    at 1. These are not timeline events
-	/// 5. Reject "due to auth events" if can't get all the auth events or some
-	///    of the auth events are also rejected "due to auth events"
-	/// 6. Reject "due to auth events" if the event doesn't pass auth based on
-	///    the auth events
-	/// 7. Persist this event as an outlier
-	/// 8. If not timeline event: stop
-	/// 9. Fetch any missing prev events doing all checks listed here starting
-	///    at 1. These are timeline events
-	/// 10. Fetch missing state and auth chain events by calling `/state_ids` at
-	///     backwards extremities doing all the checks in this list starting at
-	///     1. These are not timeline events
-	/// 11. Check the auth of the event passes based on the state of the event
-	/// 12. Ensure that the state is derived from the previous current state
-	///     (i.e. we calculated by doing state res where one of the inputs was a
-	///     previously trusted set of state, don't just trust a set of state we
-	///     got from a remote)
-	/// 13. Use state resolution to find new room state
-	/// 14. Check if the event passes auth based on the "current state" of the
-	///     room, if not soft fail it
+	/// Handles an incoming PDU from federation.
+	///
+	/// First checks that we want to receive this PDU. If we already have it as
+	/// a timeline PDU, or we don't want to receive the PDU (e.g. origin ACL'd,
+	/// room disabled/unknown), abort.
+	///
+	/// The PDU is then handled as an outlier event, which performs [PDU checks]
+	/// 1 through 4. See: `handle_outlier_pdu`.
+	///
+	/// Once handled as an outlier, any missing prev events are fetched, and
+	/// then the PDU will be promoted/upgraded from an outlier to a timeline
+	/// event clients can see. See: `upgrade_outlier_to_timeline_pdu`. After
+	/// this finishes, the PDU is either accepted or left as an outlier.
+	///
+	/// If the PDU is successfully upgraded, the remaining extremity count of
+	/// the room is checked. If there are a potentially problematic number of
+	/// forward extremities, a squasher task is started with a debounce period,
+	/// which will eventually send a dummy event that ties up as many DAG forks
+	/// as possible.
+	///
+	/// [PDU checks]: https://spec.matrix.org/v1.19/server-server-api/#checks-performed-on-receipt-of-a-pdu
 	#[tracing::instrument(
 		name = "pdu",
 		skip_all,
@@ -55,51 +46,33 @@ pub async fn handle_incoming_pdu<'a>(
 		room_id: &'a RoomId,
 		event_id: &'a EventId,
 		value: BTreeMap<String, CanonicalJsonValue>,
-		is_timeline_event: bool,
+		is_backfilled_event: bool,
 	) -> Result<Option<RawPduId>> {
-		// 1. Skip the PDU if we already have it as a timeline event
+		// Skip the PDU if we already have it as a timeline event. We still re-process
+		// outliers in this scenario.
 		if let Ok(pdu_id) = self.services.timeline.get_pdu_id(event_id).await {
+			debug!("Database hit for incoming PDU, skipping processing");
 			return Ok(Some(pdu_id));
 		}
-		if !pdu_fits(&mut value.clone()) {
-			warn!(
-				"dropping incoming PDU {event_id} in room {room_id} from {origin} because it \
-				 exceeds 65535 bytes or is otherwise too large."
-			);
-			return Err!(Request(TooLarge("PDU is too large")));
-		}
 		trace!(
 			"processing incoming PDU from {origin} for room {room_id} with event id {event_id}"
 		);

-		// 1.1 Check we even know about the room
-		let meta_exists = self.services.metadata.exists(room_id).map(Ok);
+		// If this is a membership state event for a local user, we will be interested
+		// in this event even if we aren't in the room. This allows us to process things
+		// like revoking invites over federation, without being in the room.
+		let is_interesting_member_event = value.get("type").and_then(|t| t.as_str())
+			== Some("m.room.member")
+			&& value
+				.get("state_key")
+				.and_then(|s| s.as_str())
+				.and_then(|s| UserId::parse(s).ok())
+				.is_some_and(|u| self.services.globals.user_is_local(&u));

-		// 1.2 Check if the room is disabled
-		let is_disabled = self.services.metadata.is_disabled(room_id).map(Ok);
-
-		// 1.3.1 Check room ACL on origin field/server
-		let origin_acl_check = self.acl_check(origin, room_id);
-
-		// 1.3.2 Check room ACL on sender's server name
-		let sender: OwnedUserId = value
-			.get("sender")
-			.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(BadJson("PDU does not have a valid sender key: {e}"))))?;
-
-		let sender_acl_check: OptionFuture<_> = sender
-			.server_name()
-			.ne(origin)
-			.then(|| self.acl_check(sender.server_name(), room_id))
-			.into();
-
-		let (meta_exists, is_disabled, (), ()) = try_join4(
-			meta_exists,
-			is_disabled,
-			origin_acl_check,
-			sender_acl_check.map(|o| o.unwrap_or(Ok(()))),
+		let (room_exists, is_disabled, ()) = try_join3(
+			self.services.metadata.exists(room_id).map(Ok),
+			self.services.metadata.is_disabled(room_id).map(Ok),
+			self.acl_check(origin, room_id),
 		)
 		.await
 		.inspect_err(
@@ -112,21 +85,11 @@ pub async fn handle_incoming_pdu<'a>(
 			)));
 		}

-		if !self
-			.services
-			.state_cache
-			.server_in_room(self.services.globals.server_name(), room_id)
-			.await
-		{
-			info!(
-				%origin,
-				%room_id,
-				"Dropping inbound PDU for room we aren't participating in"
-			);
-			return Err!(Request(NotFound("This server is not participating in that room.")));
-		}
-
-		if !meta_exists {
+		if !room_exists {
+			if is_interesting_member_event {
+				// TODO: handle interesting membership events where we aren't in
+				// the room
+			}
 			return Err!(Request(NotFound("Room is unknown to this server")));
 		}

@@ -152,8 +115,10 @@ pub async fn handle_incoming_pdu<'a>(
 			.handle_outlier_pdu(origin, create_event, event_id, room_id, value)
 			.await?;

-		// 8. if not timeline event: stop
-		if !is_timeline_event {
+		// If this event is being processed as part of backfill, we don't want to end up
+		// *appending* it during the upgrade process, so we return early.
+		if is_backfilled_event {
+			debug!("Not promoting incoming event as it is being backfilled");
 			return Ok(None);
 		}

@@ -166,11 +131,16 @@ pub async fn handle_incoming_pdu<'a>(
 			.await?
 			.origin_server_ts();
 		if incoming_pdu.origin_server_ts() < first_ts_in_room {
+			debug_warn!(
+				"Not promoting incoming event as it is sent before we joined the room (but was \
+				 not backfilled)"
+			);
 			return Ok(None);
 		}

-		// 9. Fetch any missing prev events doing all checks listed here starting at 1.
-		//    These are timeline events
+		// Fetch any missing prev events doing all checks listed here starting at 1.
+		// These are timeline events.
+		// TODO: This part needs to be done in a background queue somewhere.

 		debug!("Fetching and persisting any missing prev events");
 		Box::pin(self.fetch_prevs(
@@ -181,13 +151,14 @@ pub async fn handle_incoming_pdu<'a>(
 			first_ts_in_room,
 		))
 		.await
-		.debug_inspect_err(|e| {
-			error!("Failed to fetch and persist incoming event's prev_events: {e:?}");
+		.inspect_err(|e| {
+			debug_error!("Failed to fetch and persist incoming event's prev_events: {e:?}");
 		})?;

-		let is_dummy_event = incoming_pdu.event_type().to_string() == "org.matrix.dummy_event";
+		let is_dummy_event = incoming_pdu.event_type().to_string() == "org.matrix.dummy_event"
+			&& incoming_pdu.state_key().is_none();

-		// Done with prev events, now handling the incoming event
+		// Done with prev events, now we can handle promoting the PDU
 		let pdu_id = Box::pin(self.upgrade_outlier_to_timeline_pdu(
 			incoming_pdu,
 			val,
@@ -1,24 +1,25 @@
 use std::collections::{BTreeMap, HashMap, hash_map};

 use conduwuit::{
-	Err, Event, EventTypeExt, PduEvent, Result, debug, debug_info, debug_warn, err, info,
-	matrix::StateKey, state_res::auth_check, trace, warn,
-};
-use futures::future::ready;
-use ruma::{
-	CanonicalJsonObject, CanonicalJsonValue, EventId, OwnedEventId, RoomId, ServerName,
-	canonical_json::redact, events::StateEventType, room_version_rules::RoomVersionRules,
+	Err, Event, EventTypeExt, PduEvent, Result, debug, debug_warn, err, info, trace,
 };
+use ruma::{CanonicalJsonObject, CanonicalJsonValue, EventId, OwnedEventId, RoomId, ServerName};

-use super::{check_room_id, get_room_version_rules};
-use crate::rooms::timeline::pdu_fits;
+use super::get_room_version_rules;

 impl super::Service {
 	/// Handles a PDU as an outlier, performing basic checks like signatures and
 	/// hashes, proclaimed event auth, and then adding it to the outlier tree.
+	///
+	/// This performs steps 1 through 4 of [S-S section 5.1][spec], returning
+	/// the parsed PDU and modified JSON object.
+	///
+	/// **External callers likely want `handle_incoming_pdu` instead.**
+	///
+	/// [spec]: https://spec.matrix.org/v1.19/server-server-api/#checks-performed-on-receipt-of-a-pdu
 	#[allow(clippy::too_many_arguments)]
-	#[tracing::instrument(name="handle_outlier", skip_all, fields(%event_id))]
-	pub(super) async fn handle_outlier_pdu<'a, Pdu>(
+	#[tracing::instrument(name = "handle_outlier", skip_all)]
+	pub async fn handle_outlier_pdu<'a, Pdu>(
 		&self,
 		origin: &'a ServerName,
 		create_event: &'a Pdu,
@@ -29,61 +30,38 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 	where
 		Pdu: Event + Send + Sync,
 	{
-		if !pdu_fits(&mut value.clone()) {
-			warn!(
-				"dropping incoming PDU {event_id} in room {room_id} from {origin} because it \
-				 exceeds 65535 bytes or is otherwise too large."
+		// Skip outlier handling if we already have this event as either a timeline or
+		// outlier PDU.
+		if let Ok(pdu_event) = self.services.timeline.get_pdu(event_id).await {
+			debug!(
+				"Database hit for {event_id} (event is either an outlier or already promoted), \
+				 skipping outlier handling"
 			);
-			return Err!(Request(TooLarge("PDU is too large")));
+			value.insert(
+				"event_id".to_owned(),
+				CanonicalJsonValue::String(event_id.as_str().to_owned()),
+			);
+			return Ok((pdu_event, value));
 		}
-		// 1. Remove unsigned field
+
+		// 1. Check that the PDU follows the format for the room version
+		// (in this case, just size check)
+		let room_version_rules = get_room_version_rules(create_event)?;
+		Self::pdu_format_check_1(&value, &room_version_rules, create_event.event_id())
+			.inspect_err(|e| {
+				info!(
+					err=?e,
+					"Dropping incoming PDU from {origin} because it violates the room event format"
+				);
+			})?;
+
 		value.remove("unsigned");

-		// 2. Check signatures, otherwise drop
-		// 3. check content hash, redact if doesn't match
-		let room_version_rules = get_room_version_rules(create_event)?;
-		let mut incoming_pdu = match self
-			.services
-			.server_keys
-			.verify_event(&value, &room_version_rules)
-			.await
-		{
-			| 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) => {
-				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));
-				}
-
-				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(Forbidden(debug_error!(
-					"Signature verification failed for {event_id}: {e}"
-				))));
-			},
-		};
+		// 2. Check signatures, otherwise drop.
+		// 3. Check content hash, redacting the event if it fails.
+		let mut incoming_pdu = self
+			.signature_hash_check_2_3(value, &room_version_rules)
+			.await?;

 		// Now that we have checked the signature and hashes we can add the eventID and
 		// convert to our PduEvent type
@@ -91,14 +69,11 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 			"event_id".to_owned(),
 			CanonicalJsonValue::String(event_id.as_str().to_owned()),
 		);
-
 		let pdu_event = serde_json::from_value::<PduEvent>(
 			serde_json::to_value(&incoming_pdu).expect("CanonicalJsonObj is a valid JsonValue"),
 		)
 		.map_err(|e| err!(Request(BadJson(debug_warn!("Event is not a valid PDU: {e}")))))?;

-		check_room_id(room_id, &pdu_event)?;
-
 		// TODO(nex): From hereon the event is not dropped, and thus always added as an
 		// outlier. However, we only do that at the end of this function, which means
 		// several duplicated calls to add_pdu_outlier. Shouldn't we just do it here
@@ -116,7 +91,6 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(

 		for auth_event_id in pdu_event.auth_events() {
 			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 {auth_event_id} for outlier event {event_id} locally");
 				auth_events.insert(auth_event_id.to_owned(), auth_event);
 			} else {
@@ -154,7 +128,7 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 		}

 		// Ensure none of the auth events are rejected - if they are, reject too.
-		for auth_event_id in auth_events.keys() {
+		for (auth_event_id, auth_event) in &auth_events {
 			if self
 				.services
 				.pdu_metadata
@@ -166,15 +140,27 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 					 {auth_event_id}",
 					event_id,
 				);
-				self.services.pdu_metadata.mark_event_rejected(event_id);
+				self.reject_and_persist(event_id, &incoming_pdu);
 				return Err!(Request(Forbidden(
 					"Event has rejected auth event: {auth_event_id}"
 				)));
 			}
+			if auth_event.room_id_or_hash() != room_id {
+				debug_warn!(
+					%auth_event_id,
+					auth_event_room_id=%auth_event.room_id_or_hash(),
+					expected_room_id=%room_id,
+					"Rejecting incoming event which depends on an auth event in another room.",
+				);
+				self.reject_and_persist(event_id, &incoming_pdu);
+				return Err!(Request(Forbidden(
+					"Event depends on a cross-room auth event: {auth_event_id}"
+				)));
+			}
 		}

-		// 6. Reject "due to auth events" if the event doesn't pass auth based on the
-		//    auth events
+		// 4. Reject "due to auth events" if the event doesn't pass auth based on the
+		//    claimed auth events
 		debug!("Checking based on auth events");
 		let mut auth_events_by_key: HashMap<_, _> = HashMap::with_capacity(auth_events.len());
 		// Build map of auth events
@@ -184,8 +170,6 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 				.expect("we just checked that we have all auth events")
 				.to_owned();

-			check_room_id(room_id, &auth_event)?;
-
 			let key = auth_event.kind().with_state_key(
 				auth_event
 					.state_key
@@ -197,98 +181,45 @@ pub(super) async fn handle_outlier_pdu<'a, Pdu>(
 					v.insert(auth_event);
 				},
 				| hash_map::Entry::Occupied(_) => {
-					self.services
-						.outlier
-						.add_pdu_outlier(pdu_event.event_id(), &incoming_pdu);
-					self.services.pdu_metadata.mark_event_rejected(event_id);
-					return Err!(Request(Forbidden(
+					self.reject_and_persist(event_id, &incoming_pdu);
+					return Err!(Request(Forbidden(debug_warn!(
 						"Auth event's type and state_key combination exists multiple times: {}, \
 						 {}",
 						auth_event.kind,
 						auth_event.state_key().unwrap_or("")
-					)));
+					))));
 				},
 			}
 		}

 		if !self
-			.is_event_self_authorised(
+			.auth_state_check_4(
 				&pdu_event,
 				&room_version_rules,
 				create_event.as_pdu(),
 				&auth_events_by_key,
 			)
-			.await
+			.await?
 		{
-			self.services.pdu_metadata.mark_event_rejected(event_id);
-			self.services
-				.outlier
-				.add_pdu_outlier(pdu_event.event_id(), &incoming_pdu);
-			return Err!(Request(Forbidden(
+			self.reject_and_persist(event_id, &incoming_pdu);
+			return Err!(Request(Forbidden(debug_warn!(
 				"Event authorisation fails based on event's claimed auth events"
-			)));
+			))));
 		}

-		trace!("Validation successful.");
-
 		// 7. Persist the event as an outlier.
 		self.services
 			.outlier
 			.add_pdu_outlier(pdu_event.event_id(), &incoming_pdu);

-		trace!("Added pdu as outlier.");
+		debug!("PDU passed checks and has been persisted as an outlier");

 		Ok((pdu_event, incoming_pdu))
 	}

-	/// Helper method that turns the return value of `is_event_self_authorised`
-	/// into a `Result` depending on the value.
-	///
-	/// If the event is not authorised, a Forbidden error is returned.
-	/// Otherwise, an empty `Ok`.
-	pub(super) async fn is_event_self_authorised(
-		&self,
-		pdu: &PduEvent,
-		room_version_rules: &RoomVersionRules,
-		create_event: &PduEvent,
-		auth_events_by_key: &HashMap<(StateEventType, StateKey), PduEvent>,
-	) -> bool {
-		self.expect_event_is_self_authorised(
-			pdu,
-			room_version_rules,
-			create_event,
-			auth_events_by_key,
-		)
-		.await
-		.is_ok()
-	}
-
-	/// Checks PDU check 4: Passes authorisation rules based on the event's auth
-	/// events ([spec]).
-	///
-	/// If the auth check fails, false is returned, otherwise true.
-	///
-	/// [spec]: https://spec.matrix.org/v1.19/server-server-api/#checks-performed-on-receipt-of-a-pdu
-	pub(super) async fn expect_event_is_self_authorised(
-		&self,
-		pdu: &PduEvent,
-		room_version_rules: &RoomVersionRules,
-		create_event: &PduEvent,
-		auth_events_by_key: &HashMap<(StateEventType, StateKey), PduEvent>,
-	) -> Result<bool> {
-		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))
-		};
-
-		auth_check(
-			room_version_rules,
-			pdu,
-			None, // TODO: third party invite
-			state_fetch,
-			create_event,
-		)
-		.await
-		.map_err(|e| err!("Event self-authentication failed: {e:?}"))
+	/// Marks the event as rejected and then saves it as an outlier.
+	pub(super) fn reject_and_persist(&self, event_id: &EventId, pdu: &CanonicalJsonObject) {
+		self.services.pdu_metadata.mark_event_rejected(event_id);
+		self.services.outlier.add_pdu_outlier(event_id, pdu);
 	}
 }
@@ -6,6 +6,7 @@
 mod handle_incoming_pdu;
 mod handle_outlier_pdu;
 mod parse_incoming_pdu;
+pub mod pdu_checks;
 mod policy_server;
 mod resolve_state;
 mod state_at_incoming;
@@ -19,7 +20,7 @@
 	DagBuilderTree, GET_MISSING_EVENTS_MAX_BATCH_SIZE, build_local_dag,
 };
 use ruma::{
-	OwnedEventId, OwnedRoomId, RoomId, events::room::create::RoomCreateEventContent,
+	OwnedEventId, OwnedRoomId, events::room::create::RoomCreateEventContent,
 	room_version_rules::RoomVersionRules,
 };
 use tokio::sync::{Notify, mpsc};
@@ -114,22 +115,6 @@ async fn event_fetch(&self, event_id: OwnedEventId) -> Option<PduEvent> {
 	}
 }

-fn check_room_id<Pdu: Event>(room_id: &RoomId, pdu: &Pdu) -> Result {
-	if pdu
-		.room_id()
-		.is_some_and(|claimed_room_id| claimed_room_id != room_id)
-	{
-		return Err!(Request(InvalidParam(error!(
-			pdu_event_id = %pdu.event_id(),
-			pdu_room_id = pdu.room_id().map(tracing::field::display),
-			%room_id,
-			"Found event from room in room",
-		))));
-	}
-
-	Ok(())
-}
-
 fn get_room_version_rules<Pdu: Event>(create_event: &Pdu) -> Result<RoomVersionRules> {
 	let content: RoomCreateEventContent = create_event.get_content()?;
 	let Some(room_version_rules) = content.room_version.rules() else {
@@ -23,7 +23,12 @@ fn extract_room_id(event_type: &str, pdu: &CanonicalJsonObject) -> Result<OwnedR
 			.map_err(|e| err!(Request(BadJson("Invalid room_id {room_id:?} in pdu: {e}"))));
 	}
 	// If there's no room ID, and this is not a create event, it is illegal.
-	if event_type != "m.room.create" || pdu.get("state_key").is_none() {
+	let is_create = event_type == "m.room.create"
+		&& pdu
+			.get("state_key")
+			.and_then(|v| v.as_str())
+			.is_some_and(str::is_empty);
+	if !is_create {
 		return Err!(Request(BadJson("Missing room_id in pdu")));
 	}

@@ -42,10 +47,7 @@ fn extract_room_id(event_type: &str, pdu: &CanonicalJsonObject) -> Result<OwnedR
 		return Err!(Request(BadJson("Unknown room version in pdu")));
 	};

-	if !room_version_rules
-		.authorization
-		.room_create_event_id_as_room_id
-	{
+	if room_version_rules.event_format.require_room_create_room_id {
 		return Err!(Request(BadJson("Missing room_id in pdu")));
 	}

@@ -80,45 +82,14 @@ pub(super) fn expect_event_id_array(
 }

 impl super::Service {
-	/// Performs some basic validation on the PDU to make sure it's not
-	/// obviously malformed. This is not a full validation, but guards against
-	/// extreme errors.
-	///
-	/// Currently, this just validates that prev/auth events are within
-	/// acceptable ranges. Other servers do some additional things like
-	/// checking depth range, but serde will do that later when converting the
-	/// object to a PduEvent.
-	pub fn validate_pdu(&self, pdu: &CanonicalJsonObject) -> Result {
-		// Since v3:
-		// `event_id` should not be present on the PDU.
-		// NOTE: The above is ignored since technically it's still allowed to be
-		// included, but should be ignored instead.
-		// `auth_events` and `prev_events` must be an array of event IDs
-		let auth_events = expect_event_id_array(pdu, "auth_events")?;
-		if auth_events.len() > 10 {
-			return Err!(Request(BadJson("PDU has too many auth events")));
-		}
-		let prev_events = expect_event_id_array(pdu, "prev_events")?;
-		if prev_events.len() > 20 {
-			return Err!(Request(BadJson("PDU has too many prev events")));
-		}
-		Ok(())
-	}
-
-	pub async fn parse_incoming_pdu_with_known_room(
+	/// Parses an incoming PDU JSON object, generating an event ID for it and
+	/// attempts to discover the associated room ID. Does not insert the event
+	/// ID into the returned object.
+	pub async fn parse_incoming_pdu(
 		&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))
-	}
-
-	pub async fn parse_incoming_pdu(&self, pdu: &RawJsonValue) -> Result<Parsed> {
+		room_version_rules: Option<&RoomVersionRules>,
+	) -> Result<Parsed> {
 		let value = serde_json::from_str::<CanonicalJsonObject>(pdu.get()).map_err(|e| {
 			err!(BadServerResponse(debug_warn!("Error parsing incoming event {e:?}")))
 		})?;
@@ -129,20 +100,23 @@ pub async fn parse_incoming_pdu(&self, pdu: &RawJsonValue) -> Result<Parsed> {

 		let room_id = extract_room_id(event_type, &value)?;

-		let room_version_rules = self
-			.services
-			.state
-			.get_room_version(&room_id)
-			.await
-			.unwrap_or(RoomVersionId::V1)
-			.rules()
-			.unwrap();
+		let room_version_rules = match room_version_rules {
+			| Some(r) => r,
+			| None => &self
+				.services
+				.state
+				.get_room_version(&room_id)
+				.await
+				.unwrap_or(RoomVersionId::V1)
+				.rules()
+				.expect("room version must be supported"),
+		};

 		let (event_id, value) =
-			gen_event_id_canonical_json(pdu, &room_version_rules).map_err(|e| {
+			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)?;
+		// NOTE: validation checks are now performed by `pdu_format_check_1`.
 		Ok((room_id, event_id, value))
 	}
 }
@@ -0,0 +1,291 @@
+use std::collections::HashMap;
+
+use conduwuit::{
+	Err, Event, EventTypeExt, PduEvent, Result, debug, debug::DebugInspect, debug_error,
+	debug_info, err, info, matrix::StateKey, state_res, trace,
+};
+use futures::future::ready;
+use ruma::{
+	CanonicalJsonObject, EventId, OwnedEventId, ServerName, api::error::ErrorKind,
+	canonical_json::redact, events::StateEventType, room_version_rules::RoomVersionRules,
+};
+
+use crate::rooms::{
+	event_handler::parse_incoming_pdu::expect_event_id_array, timeline::pdu_fits,
+};
+
+impl super::Service {
+	/// Checks that the PDU conforms to the PDU format (check 1). This is
+	/// already mostly done during deserialisation, so this function just checks
+	/// that the PDU isn't a too large.
+	pub fn pdu_format_check_1(
+		pdu_json: &CanonicalJsonObject,
+		room_version_rules: &RoomVersionRules,
+		create_event_id: &EventId,
+	) -> Result<()> {
+		let event_format = &room_version_rules.event_format;
+		// NOTE: if we do any more validation outside of deserialisation, it has to be
+		// done here.
+
+		if !pdu_fits(pdu_json) {
+			return Err!(Request(TooLarge("PDU is too large")));
+		}
+
+		if event_format.require_room_create_room_id {
+			if pdu_json.get("room_id").is_none() {
+				return Err!(Request(BadJson("Missing required PDU field: `room_id`")));
+			}
+		}
+
+		let auth_events = expect_event_id_array(pdu_json, "auth_events")?;
+		if auth_events.len() > 10 {
+			return Err!(Request(BadJson("PDU has too many auth events")));
+		}
+
+		let create_event_in_auth_events = auth_events.iter().any(|id| id == create_event_id);
+		if !event_format.allow_room_create_in_auth_events && create_event_in_auth_events {
+			return Err!(Request(BadJson("PDU references a create event")));
+		} else if event_format.allow_room_create_in_auth_events && !create_event_in_auth_events {
+			return Err!(Request(BadJson("PDU does not reference the room create event")));
+		}
+
+		let prev_events = expect_event_id_array(pdu_json, "prev_events")?;
+		if prev_events.len() > 20 {
+			return Err!(Request(BadJson("PDU has too many prev events")));
+		}
+
+		Ok(())
+	}
+
+	/// Checks that the PDU has a valid signature (check 2), and redacts it if
+	/// the content hash verification fails (check 3), returning the
+	/// potentially modified JSON. Returns an error if the PDU cannot be
+	/// redacted, or fails signature verification.
+	pub async fn signature_hash_check_2_3(
+		&self,
+		pdu_json: CanonicalJsonObject,
+		room_version_rules: &RoomVersionRules,
+	) -> Result<CanonicalJsonObject> {
+		match self
+			.services
+			.server_keys
+			.verify_event(&pdu_json, room_version_rules)
+			.await
+		{
+			| Ok(ruma::signatures::Verified::All) => {
+				trace!("Signatures and hashes verified successfully");
+				Ok(pdu_json)
+			},
+			| Ok(ruma::signatures::Verified::Signatures) => {
+				debug_info!("Content hash mismatch, redacting event and continuing");
+				let redacted = redact(pdu_json, &room_version_rules.redaction, None)
+					.map_err(|e| err!(Request(BadJson("Unable to redact event: {e}"))))?;
+				Ok(redacted)
+			},
+			| Err(e) => {
+				Err!(Request(Forbidden(debug_error!("Signature verification failed: {e}"))))
+			},
+		}
+	}
+
+	/// Checks PDU check 4: Passes authorisation rules based on the event's auth
+	/// events ([spec]).
+	///
+	/// If the auth check fails, false is returned, otherwise true.
+	///
+	/// [spec]: https://spec.matrix.org/v1.19/server-server-api/#checks-performed-on-receipt-of-a-pdu
+	pub async fn auth_state_check_4(
+		&self,
+		pdu: &PduEvent,
+		room_version_rules: &RoomVersionRules,
+		create_event: &PduEvent,
+		auth_events_by_key: &HashMap<(StateEventType, StateKey), PduEvent>,
+	) -> Result<bool> {
+		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))
+		};
+
+		state_res::event_auth::auth_check(
+			room_version_rules,
+			pdu,
+			None, // TODO: third party invite
+			state_fetch,
+			create_event,
+		)
+		.await
+		.map_err(|e| err!("Event self-authentication failed: {e:?}"))
+	}
+
+	/// Checks that the event passes PDU check 5, which ensures that the event
+	/// is authorised based on the state before the event (which is the resolved
+	/// state across all prev events).
+	///
+	/// Returns a boolean indicating whether the event is authorised, and also
+	/// the resolved state before the event for later use. Returns an error if
+	/// state fetching or auth checking fails.
+	pub(super) async fn state_before_check_5(
+		&self,
+		incoming_pdu: &PduEvent,
+		room_version_rules: &RoomVersionRules,
+		create_event: &PduEvent,
+		origin: &ServerName,
+	) -> Result<(bool, HashMap<u64, OwnedEventId>)> {
+		debug!(
+			event_id = %incoming_pdu.event_id,
+			"Resolving state at event"
+		);
+		let room_id = incoming_pdu.room_id_or_hash();
+
+		// If the incoming event only has one prev event, we can just use the state at
+		// that event, but otherwise we have to resolve across each fork. If we're
+		// missing even one of the prev events, we have to ask a remote server for help.
+		//
+		// TODO: this can be optimised by only loading auth chain events into memory,
+		// rather than the entire state.
+		let state_before = self
+			.state_before_incoming(&incoming_pdu, room_version_rules)
+			.await?;
+		let state_before = match state_before {
+			| 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
+					.inspect_err(|e| {
+						debug_error!("Could not fetch state from {origin}: {e}");
+					})?
+			},
+		};
+
+		if state_before.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 before event")));
+		}
+		trace!(state_events = state_before.len(), "Calculated incoming state");
+
+		let state_fetch_state = &state_before;
+		let state_fetch = |k: StateEventType, s: StateKey| async move {
+			let shortstatekey = self.services.short.get_shortstatekey(&k, &s).await.ok()?;
+
+			let event_id = state_fetch_state.get(&shortstatekey)?;
+			self.services.timeline.get_pdu(event_id).await.ok()
+		};
+
+		debug!(
+			event_id = %incoming_pdu.event_id,
+			"Running state-before auth check"
+		);
+
+		// PDU check: 5
+		let auth_check = state_res::event_auth::auth_check(
+			room_version_rules,
+			incoming_pdu,
+			None, // TODO: third party invite
+			|ty, sk| state_fetch(ty.clone(), sk.into()),
+			create_event.as_pdu(),
+		)
+		.await
+		.map_err(|e| err!(Request(Forbidden("Auth check failed: {e:?}"))))?;
+		Ok((auth_check, state_before))
+	}
+
+	/// Checks that the event passes PDU check 6, which ensures that the event
+	/// is authorised based on the room's current state (which is the resolved
+	/// state across all current forward extremities).
+	///
+	/// Returns a boolean indicating whether the event is authorised, or an
+	/// error if the auth check fails.
+	pub(super) async fn current_state_check_6(
+		&self,
+		incoming_pdu: &PduEvent,
+		room_version_rules: &RoomVersionRules,
+		create_event: &PduEvent,
+	) -> Result<bool> {
+		debug!(
+			event_id = %incoming_pdu.event_id,
+			"Gathering auth events"
+		);
+		let auth_events = self
+			.services
+			.state
+			.get_auth_events(
+				&incoming_pdu.room_id_or_hash(),
+				incoming_pdu.kind(),
+				incoming_pdu.sender(),
+				incoming_pdu.state_key(),
+				incoming_pdu.content(),
+				room_version_rules,
+			)
+			.await?;
+
+		let state_fetch = |k: &StateEventType, s: &str| {
+			let key = k.with_state_key(s);
+			ready(auth_events.get(&key).map(ToOwned::to_owned))
+		};
+
+		debug!(
+			event_id = %incoming_pdu.event_id,
+			"Running current state auth check"
+		);
+		state_res::event_auth::auth_check(
+			room_version_rules,
+			incoming_pdu,
+			None, // third-party invite
+			state_fetch,
+			create_event.as_pdu(),
+		)
+		.await
+		.map_err(|e| err!(Request(Forbidden("Auth check failed: {e:?}"))))
+	}
+
+	/// Performs PDU check 7 - does the policy server allow this event.
+	///
+	/// If the policy server forbids the event, false is returned. If there is a
+	/// problem contacting the policy server, or it returns an unrecognised
+	/// response, an appropriate error is returned.
+	pub(super) async fn policy_server_check_7(
+		&self,
+		incoming_pdu: &PduEvent,
+		pdu_json: &mut CanonicalJsonObject,
+		room_version_rules: &RoomVersionRules,
+	) -> Result<bool> {
+		let event_id = pdu_json
+			.remove("event_id")
+			.expect("event_id should be present in pdu_json at this stage");
+		if let Err(e) = self
+			.policy_server_allows_event(
+				incoming_pdu,
+				pdu_json,
+				&incoming_pdu.room_id_or_hash(),
+				room_version_rules,
+				true,
+			)
+			.await
+			.debug_inspect(|()| {
+				debug!(
+					event_id = %incoming_pdu.event_id,
+					"Event has passed policy server check."
+				);
+			}) {
+			return if matches!(e.kind(), ErrorKind::Forbidden) {
+				info!(
+					event_id = %incoming_pdu.event_id,
+					error = %e,
+					"Event has been marked as spam by policy server: {}",
+					e.message(),
+				);
+				Ok(false)
+			} else {
+				Err(e)
+			};
+		}
+		pdu_json.insert("event_id".to_owned(), event_id);
+		Ok(true)
+	}
+}
@@ -16,10 +16,31 @@
 use crate::rooms::short::ShortStateHash;

 impl super::Service {
-	// TODO: if we know the prev_events of the incoming event we can avoid the
-	// request and build the state from a known point and resolve if > 1 prev_event
+	/// Resolves the state before the incoming event.
+	///
+	/// If we do not know enough information to resolve the state, `Ok(None)` is
+	/// returned, and the caller will have to figure it out some other way (e.g.
+	/// by fetching the state from a remote server).
+	pub(super) async fn state_before_incoming<Pdu>(
+		&self,
+		incoming_pdu: &Pdu,
+		room_version_rules: &RoomVersionRules,
+	) -> Result<Option<HashMap<u64, OwnedEventId>>>
+	where
+		Pdu: Event + Send + Sync,
+	{
+		if incoming_pdu.prev_events().count() == 1 {
+			self.state_before_incoming_degree_one(incoming_pdu).await
+		} else {
+			self.state_before_incoming_resolved(incoming_pdu, room_version_rules)
+				.await
+		}
+	}
+
+	/// Determines the state before the incoming pdu, when it has only one prev
+	/// event. This is a special case that does not require state resolution.
 	#[tracing::instrument(name = "state", level = "debug", skip_all)]
-	pub(super) async fn state_at_incoming_degree_one<Pdu>(
+	async fn state_before_incoming_degree_one<Pdu>(
 		&self,
 		incoming_pdu: &Pdu,
 	) -> Result<Option<HashMap<u64, OwnedEventId>>>
@@ -66,7 +87,7 @@ pub(super) async fn state_at_incoming_degree_one<Pdu>(
 				.await;

 			state.insert(shortstatekey, prev_event.to_owned());
-			// Now it's the state after the pdu
+			// Now it's the state at the pdu
 		}

 		debug_assert!(!state.is_empty(), "should be returning None for empty HashMap result");
@@ -74,11 +95,14 @@ pub(super) async fn state_at_incoming_degree_one<Pdu>(
 		Ok(Some(state))
 	}

+	/// Resolves the state before the incoming pdu across all of its prev
+	/// events. If we do not know enough information to resolve the state,
+	/// `Ok(None)` is returned, and the caller will have to figure it out some
+	/// other way (e.g. by fetching the state from a remote server).
 	#[tracing::instrument(name = "state", level = "debug", skip_all)]
-	pub(super) async fn state_at_incoming_resolved<Pdu>(
+	async fn state_before_incoming_resolved<Pdu>(
 		&self,
 		incoming_pdu: &Pdu,
-		room_id: &RoomId,
 		room_version_rules: &RoomVersionRules,
 	) -> Result<Option<HashMap<u64, OwnedEventId>>>
 	where
@@ -108,6 +132,7 @@ pub(super) async fn state_at_incoming_resolved<Pdu>(
 		};

 		trace!("Calculating fork states...");
+		let room_id = &incoming_pdu.room_id_or_hash();
 		let (fork_states, auth_chain_sets): (Vec<StateMap<_>>, Vec<HashSet<_>>) =
 			extremity_sstatehashes
 				.into_iter()
@@ -145,6 +170,8 @@ pub(super) async fn state_at_incoming_resolved<Pdu>(
 			.await
 	}

+	/// Determines the state at an incoming fork (aka the state at a prev
+	/// event), returning the resolved state and its associated auth chain.
 	async fn state_at_incoming_fork<Pdu>(
 		&self,
 		room_id: &RoomId,
@@ -1,27 +1,15 @@
-use std::{borrow::Borrow, sync::Arc, time::Instant};
+use std::time::Instant;

 use conduwuit::{
-	Err, Result, debug, debug_error, debug_info, err, info, is_equal_to,
-	matrix::{Event, EventTypeExt, PduEvent, StateKey, state_res},
-	result::DebugInspect,
+	Err, Result, debug, debug_info, debug_warn, is_true,
+	matrix::{Event, PduEvent},
 	trace,
-	utils::{
-		IterStream,
-		stream::{BroadbandExt, ReadyExt},
-	},
-	warn,
-};
-use futures::{FutureExt, StreamExt, future::ready};
-use ruma::{
-	CanonicalJsonObject, RoomId, ServerName, api::error::ErrorKind, events::StateEventType,
 };
+use ruma::{CanonicalJsonObject, RoomId, ServerName, events::StateEventType};
 use tokio::join;

 use super::get_room_version_rules;
-use crate::rooms::{
-	state_compressor::{CompressedState, HashSetCompressStateEvent},
-	timeline::RawPduId,
-};
+use crate::rooms::timeline::RawPduId;

 impl super::Service {
 	#[tracing::instrument(name="upgrade_outlier", skip_all, fields(event_id=%incoming_pdu.event_id()))]
@@ -46,16 +34,24 @@ pub(super) async fn upgrade_outlier_to_timeline_pdu(
 			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")));
+			return Err!(Request(Forbidden(debug_info!("Event has been rejected"))));
 		} else if soft_failed {
-			return Err!(Request(Forbidden("Event has been soft-failed")));
+			// Soft-failed events cannot be promoted.
+			return Err!(Request(Forbidden(debug_info!("Event has been soft-failed"))));
 		}

+		// These should never happen, but they're good last-minute sanity checks to
+		// ensure we never promote totally illegal events.
 		assert_eq!(
 			*create_event.kind(),
 			StateEventType::RoomCreate.into(),
 			"tried to upgrade a PDU with a create_event that is not a room create event"
 		);
+		assert_eq!(
+			incoming_pdu.room_id_or_hash(),
+			*room_id,
+			"room ID mismatch: PDU room ID differs from parameter"
+		);

 		debug!(
 			event_id = %incoming_pdu.event_id,
@@ -65,326 +61,118 @@ pub(super) async fn upgrade_outlier_to_timeline_pdu(
 		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
-		//     backwards extremities doing all the checks in this list starting at 1.
-		//     These are not timeline events.
-
-		debug!(
-			event_id = %incoming_pdu.event_id,
-			"Resolving state at event"
-		);
-		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_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")));
-		}
-		trace!(state_events = state_at_incoming_event.len(), "Calculated incoming state");
-
-		debug!(
-			event_id = %incoming_pdu.event_id,
-			"Performing auth check to upgrade"
-		);
-		// 11. Check the auth of the event passes based on the state of the event
-		let state_fetch_state = &state_at_incoming_event;
-		let state_fetch = |k: StateEventType, s: StateKey| async move {
-			let shortstatekey = self.services.short.get_shortstatekey(&k, &s).await.ok()?;
-
-			let event_id = state_fetch_state.get(&shortstatekey)?;
-			self.services.timeline.get_pdu(event_id).await.ok()
-		};
-
-		debug!(
-			event_id = %incoming_pdu.event_id,
-			"Running initial auth check"
-		);
-		// PDU check: 5
-		let auth_check = state_res::event_auth::auth_check(
-			&room_version_rules,
-			&incoming_pdu,
-			None, // TODO: third party invite
-			|ty, sk| state_fetch(ty.clone(), sk.into()),
-			create_event.as_pdu(),
-		)
-		.await
-		.map_err(|e| err!(Request(Forbidden("Auth check failed: {e:?}"))))?;
-
-		if !auth_check {
-			self.services
-				.pdu_metadata
-				.mark_event_rejected(incoming_pdu.event_id());
-			return Err!(Request(Forbidden(
-				"Event authorisation fails based on the state before the event"
-			)));
-		}
-
-		debug!(
-			event_id = %incoming_pdu.event_id,
-			"Gathering auth events"
-		);
-		let auth_events = self
-			.services
-			.state
-			.get_auth_events(
-				room_id,
-				incoming_pdu.kind(),
-				incoming_pdu.sender(),
-				incoming_pdu.state_key(),
-				incoming_pdu.content(),
-				&room_version_rules,
-			)
+		// We now need to resolve the state before the event so that we can perform PDU
+		// check 5 (event auth passes based on state before the event). To do this, we
+		// either need to have all the prev events locally, or ask a remote server
+		// for the state at the event.
+		let (passes_state_before, state_before) = self
+			.state_before_check_5(&incoming_pdu, &room_version_rules, create_event, origin)
 			.await?;

-		let state_fetch = |k: &StateEventType, s: &str| {
-			let key = k.with_state_key(s);
-			ready(auth_events.get(&key).map(ToOwned::to_owned))
-		};
-
-		debug!(
-			event_id = %incoming_pdu.event_id,
-			"Running auth check with claimed state auth"
-		);
-		// PDU check: 6
-		let auth_check = state_res::event_auth::auth_check(
-			&room_version_rules,
-			&incoming_pdu,
-			None, // third-party invite
-			state_fetch,
-			create_event.as_pdu(),
-		)
-		.await
-		.map_err(|e| err!(Request(Forbidden("Auth check failed: {e:?}"))))?;
-		if !auth_check {
-			warn!(
-				event_id = %incoming_pdu.event_id,
-				"Event authorization fails based on the current state of the room"
-			);
+		if !passes_state_before {
+			self.reject_and_persist(incoming_pdu.event_id(), &val);
+			return Err!(Request(Forbidden(debug_warn!(
+				"Event authorisation fails based on the state before the event"
+			))));
 		}

-		// Soft fail check before doing state res
-		debug!(
-			event_id = %incoming_pdu.event_id,
-			"Performing soft-fail check"
-		);
-		let mut soft_fail = match (auth_check, incoming_pdu.redacts_id(&room_version_rules)) {
-			| (false, _) => true,
-			| (true, None) => false,
-			| (true, Some(redact_id)) => {
-				if !self
-					.services
-					.state_accessor
-					.user_can_redact(&redact_id, incoming_pdu.sender(), room_id, true)
-					.await?
-				{
-					warn!(redacts = %redact_id, "User is not allowed to redact event");
-					true
-				} else {
-					false
-				}
-			},
-		};
+		// Now that we know the event passes both self-authentication, and
+		// authentication based on the state before the event, we need to check that it
+		// passes based on the *current* room state (state across all forward
+		// extremities). If it doesn't, we accept it, but soft-fail it, and this
+		// prevents it being promoted.

-		// 13. Use state resolution to find new room state
-		// We start looking at current room state now, so lets lock the room
+		// We lock the room here to prevent the current state from changing beneath us
+		// mid-check.
 		trace!(
 			room_id = %room_id,
 			"Locking the room"
 		);
 		let state_lock = self.services.state.mutex.lock(room_id).await;
-
-		let state_ids_compressed: Arc<CompressedState> = self
-			.services
-			.state_compressor
-			.compress_state_events(
-				state_at_incoming_event
-					.iter()
-					.map(|(ssk, eid)| (ssk, eid.borrow())),
-			)
-			.collect()
-			.map(Arc::new)
-			.await;
-
-		if incoming_pdu.state_key().is_some() {
-			debug!("Event is a state-event. Deriving new room state");
-
-			// We also add state after incoming event to the fork states
-			let mut state_after = state_at_incoming_event.clone();
-			if let Some(state_key) = incoming_pdu.state_key() {
-				let shortstatekey = self
-					.services
-					.short
-					.get_or_create_shortstatekey(
-						&incoming_pdu.kind().to_string().into(),
-						state_key,
-					)
-					.await;
-
-				let event_id = incoming_pdu.event_id();
-				state_after.insert(shortstatekey, event_id.to_owned());
-			}
-
-			let new_room_state = self
-				.resolve_state(room_id, &room_version_rules, state_after)
-				.await?;
-
-			// Set the new room state to the resolved state
-			debug!("Forcing new room state");
-			let HashSetCompressStateEvent { shortstatehash, added, removed } = self
-				.services
-				.state_compressor
-				.save_state(room_id, new_room_state)
-				.await?;
-
-			self.services
-				.state
-				.force_state(room_id, shortstatehash, added, removed, &state_lock)
-				.await?;
-		}
-
-		if !soft_fail {
-			// Don't call the below checks on events that have already soft-failed, there's
-			// no reason to re-calculate that.
-			// 14-pre. ask the policy server to sign the event, if possible
-			debug!(event_id = %incoming_pdu.event_id, "Checking policy server for event");
-			let tmp_evt_id = val.remove("event_id");
-			if let Err(e) = self
-				.policy_server_allows_event(
-					&incoming_pdu,
-					&mut val,
-					room_id,
-					&room_version_rules,
-					true,
-				)
-				.await
-			{
-				if matches!(e.kind(), ErrorKind::Forbidden) {
-					info!(
-						event_id = %incoming_pdu.event_id,
-						error = %e,
-						"Event has been marked as spam by policy server: {}",
-						e.message(),
+		let passes_current_state = self
+			.current_state_check_6(&incoming_pdu, &room_version_rules, create_event)
+			.await
+			.inspect(|passes| {
+				if !*passes {
+					debug_warn!(
+						"Event authorisation fails based on the current room state - will be \
+						 soft-failed"
 					);
-					soft_fail = true;
-				} else {
-					return Err(e);
 				}
-			} else {
-				debug!(
-					event_id = %incoming_pdu.event_id,
-					"Event has passed policy server check."
-				);
-			}
-			if let Some(id) = tmp_evt_id {
-				val.insert("event_id".to_owned(), id);
-			}
+			})?;

-			// Additionally, if this is a redaction for a soft-failed event, we soft-fail it
-			// also.
+		// Determine whether this PDU should be soft-failed.
+		// If the auth check failed, invariably yes. Otherwise, only if the user isn't
+		// allowed to redact the target event (if any).
+		let mut should_soft_fail =
+			match (passes_current_state, incoming_pdu.redacts_id(&room_version_rules)) {
+				| (false, _) => true,
+				| (true, None) => false,
+				| (true, Some(redact_id)) => self
+					.services
+					.state_accessor
+					.user_can_redact(&redact_id, incoming_pdu.sender(), room_id, true)
+					.await
+					.is_ok_and(is_true!()),
+			};

-			// TODO: this is supposed to hide redactions from policy servers, however, for
-			// full efficacy it also needs to hide redactions for unknown events. This
-			// needs to be investigated at a later time.
+		if !should_soft_fail {
+			// Now we can perform check 7, which is ensuring the event passes policy server
+			// checks.
+			// We explicitly only do this if we aren't already going to soft-fail the event,
+			// since the policy server refusing this event also soft-fails it.
+			debug!(event_id = %incoming_pdu.event_id, "Checking policy server for event");
+			should_soft_fail = !self
+				.policy_server_check_7(&incoming_pdu, &mut val, &room_version_rules)
+				.await
+				.inspect(|passes| {
+					if !*passes {
+						debug_warn!(
+							"Event did not pass the policy server check and will be soft-failed"
+						);
+					}
+				})?;
+
+			// TODO: this is supposed to hide redactions from policy servers and janitorial
+			// bots, however, for full efficacy it also needs to hide redactions for
+			// unknown events. This needs to be investigated at a later time.
 			if let Some(redact_id) = incoming_pdu.redacts_id(&room_version_rules) {
 				debug!(
 					redact_id = %redact_id,
-					"Checking if redaction is for a soft-failed event"
+					"Checking if redaction is for a soft-failed/rejected event"
 				);
-				if self
+				if !self
 					.services
 					.pdu_metadata
-					.is_event_soft_failed(&redact_id)
+					.is_event_accepted(&redact_id)
 					.await
 				{
-					info!(
-						redact_id = %redact_id,
-						"Redaction is for a soft-failed event"
+					debug_info!(
+						"Soft-failing valid redaction because it targets a non-accepted event"
 					);
-					soft_fail = true;
+					should_soft_fail = true;
 				}
 			}
 		}

+		// The PDU has now passed all checks! We can now promote it (or soft-fail it if
+		// the verdict is such).
 		trace!("Appending pdu to timeline");
-		let mut extremities: Vec<_> = self
-			.services
-			.state
-			.get_forward_extremities(room_id)
-			.collect()
-			.await;
-		if !soft_fail {
-			// Per https://spec.matrix.org/unstable/server-server-api/#soft-failure, soft-failed events
-			// are not added as forward extremities.
-
-			// Now we calculate the set of extremities this room has after the incoming
-			// event has been applied. We start with the previous extremities (aka leaves)
-			trace!("Calculating extremities");
-			extremities = extremities
-				.into_iter()
-				.stream()
-				.ready_filter(|event_id| {
-					// Remove any that are referenced by this incoming event's prev_events
-					!incoming_pdu.prev_events().any(is_equal_to!(event_id))
-				})
-				.broad_filter_map(|event_id| async move {
-					// Only keep those extremities were not referenced yet
-					self.services
-						.pdu_metadata
-						.is_event_referenced(room_id, &event_id)
-						.await
-						.eq(&false)
-						.then_some(event_id)
-				})
-				.collect::<Vec<_>>()
-				.await;
-			extremities.push(incoming_pdu.event_id().to_owned());
-			debug!(
-				"Retained {} extremities checked against {} prev_events",
-				extremities.len(),
-				incoming_pdu.prev_events().count()
-			);
-			assert!(!extremities.is_empty(), "extremities must not empty");
-		}
-
 		let pdu_id = self
 			.services
 			.timeline
 			.append_incoming_pdu(
 				&incoming_pdu,
 				val,
-				extremities.iter().map(Borrow::borrow),
-				state_ids_compressed,
-				soft_fail,
+				&room_version_rules,
+				state_before,
+				should_soft_fail,
 				&state_lock,
-				room_id,
 			)
 			.await?;
-		if soft_fail {
-			self.services
-				.pdu_metadata
-				.mark_event_soft_failed(incoming_pdu.event_id());

-			info!(
+		if should_soft_fail {
+			debug_info!(
 				elapsed = ?timer.elapsed(),
 				event_id = %incoming_pdu.event_id,
 				"Event was soft failed"
@@ -520,7 +520,7 @@ pub async fn join_remote_room(
 						return state;
 					},
 				};
-				if !pdu_fits(&mut value.clone()) {
+				if !pdu_fits(&value.clone()) {
 					warn!(
 						"dropping incoming PDU {event_id} in room {room_id} from room join \
 						 because it exceeds 65535 bytes or is otherwise too large."
@@ -1,7 +1,7 @@
 use std::{collections::HashMap, fmt::Write, sync::Arc};

 use async_trait::async_trait;
-use conduwuit::debug;
+use conduwuit::{debug, utils::stream::WidebandExt};
 use conduwuit_core::{
 	Event, PduEvent, Result, err,
 	result::FlatOk,
@@ -30,7 +30,7 @@
 		short::{ShortEventId, ShortStateHash},
 		state_compressor::{CompressedState, parse_compressed_state_event},
 	},
-	sync,
+	sending, sync,
 };

 pub struct Service {
@@ -45,6 +45,7 @@ struct Services {
 	state_cache: Dep<rooms::state_cache::Service>,
 	state_accessor: Dep<rooms::state_accessor::Service>,
 	state_compressor: Dep<rooms::state_compressor::Service>,
+	sending: Dep<sending::Service>,
 	sync: Dep<sync::Service>,
 	timeline: Dep<rooms::timeline::Service>,
 }
@@ -71,6 +72,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 					.depend::<rooms::state_accessor::Service>("rooms::state_accessor"),
 				state_compressor: args
 					.depend::<rooms::state_compressor::Service>("rooms::state_compressor"),
+				sending: args.depend::<sending::Service>("sending"),
 				sync: args.depend::<sync::Service>("sync"),
 				timeline: args.depend::<rooms::timeline::Service>("rooms::timeline"),
 			},
@@ -307,6 +309,7 @@ pub async fn summary_stripped(
 		event: &PduEvent,
 		room_id: &RoomId,
 		target_user: &UserId,
+		federation: bool,
 	) -> Vec<RawStrippedState> {
 		let mut state_events = [
 			(&StateEventType::RoomCreate, ""),
@@ -343,8 +346,20 @@ pub async fn summary_stripped(
 			.await
 			.into_iter()
 			.filter_map(Result::ok)
-			.map(|pdu| RawStrippedState::Pdu(serde_json::value::to_raw_value(&pdu).unwrap()))
+			.stream()
+			.wide_then(async |pdu| {
+				let formatted = if federation {
+					self.services
+						.sending
+						.convert_to_outgoing_federation_event(pdu.to_canonical_object())
+						.await
+				} else {
+					serde_json::value::to_raw_value(&pdu).unwrap()
+				};
+				RawStrippedState::Pdu(formatted)
+			})
 			.collect()
+			.await
 	}

 	/// Set the state hash to a new version, but does not update state_cache.
@@ -114,7 +114,7 @@ pub async fn update_membership(
 				let invite_state = if is_local {
 					self.services
 						.state
-						.summary_stripped(pdu, room_id, user_id)
+						.summary_stripped(pdu, room_id, user_id, false)
 						.await
 				} else {
 					vec![]
@@ -1,69 +1,113 @@
 use std::{
-	collections::{BTreeMap, HashSet},
+	borrow::Borrow,
+	collections::{BTreeMap, HashMap, HashSet},
 	sync::Arc,
 };

 use conduwuit::{
-	debug_warn,
+	Result, debug, debug_warn, is_equal_to,
+	matrix::{Event, PduEvent},
 	pdu::{Count, ShortRoomId},
 	trace,
-	utils::{IterStream, TryFutureExtExt, stream::BroadbandExt},
+	utils::{
+		IterStream, TryFutureExtExt,
+		mutex_map::Guard,
+		stream::{BroadbandExt, ReadyExt},
+	},
 	warn,
 };
 use conduwuit_core::{
-	Result, err, error,
-	matrix::{
-		event::Event,
-		pdu::{PduCount, PduEvent, PduId, RawPduId},
-	},
-	utils::{self, ReadyExt},
+	err, error,
+	matrix::pdu::{PduCount, PduId, RawPduId},
+	utils::{self},
 };
-use futures::{StreamExt, TryFutureExt};
+use futures::{FutureExt, StreamExt, TryFutureExt};
 use ruma::{
-	CanonicalJsonObject, CanonicalJsonValue, EventId, RoomId, RoomVersionId, UserId,
+	CanonicalJsonObject, CanonicalJsonValue, EventId, OwnedEventId, OwnedRoomId, RoomId,
+	RoomVersionId, UserId,
 	events::{
 		GlobalAccountDataEventType, TimelineEventType,
 		push_rules::PushRulesEvent,
 		room::{encrypted::Relation, redaction::RoomRedactionEventContent},
 	},
 	push::{Action, Ruleset, Tweak},
+	room_version_rules::RoomVersionRules,
 };

 use super::{ExtractBody, ExtractRelatesTo, ExtractRelatesToEventId, RoomMutexGuard};
-use crate::{appservice::RegistrationInfo, rooms::state_compressor::CompressedState};
+use crate::{
+	appservice::RegistrationInfo,
+	rooms::state_compressor::{CompressedState, HashSetCompressStateEvent},
+};

 impl super::Service {
 	/// Append the incoming event setting the state snapshot to the state from
 	/// the server that sent the event.
-	#[allow(clippy::too_many_arguments)]
-	pub async fn append_incoming_pdu<'a, Leaves>(
+	pub async fn append_incoming_pdu<'a>(
 		&'a self,
 		pdu: &'a PduEvent,
 		pdu_json: CanonicalJsonObject,
-		new_room_leaves: Leaves,
-		state_ids_compressed: Arc<CompressedState>,
-		soft_fail: bool,
+		room_version_rules: &RoomVersionRules,
+		state_before: HashMap<u64, OwnedEventId>,
+		should_soft_fail: bool,
 		state_lock: &'a RoomMutexGuard,
-		room_id: &'a RoomId,
-	) -> Result<Option<RawPduId>>
-	where
-		Leaves: Iterator<Item = &'a EventId> + Send + 'a,
-	{
+	) -> Result<Option<RawPduId>> {
+		let room_id = pdu.room_id_or_hash();
+
+		let sb = state_before.iter().map(|(ssk, eid)| (ssk, eid.as_ref()));
+		let state_ids_compressed: Arc<CompressedState> = self
+			.services
+			.state_compressor
+			.compress_state_events(sb)
+			.collect()
+			.map(Arc::new)
+			.await;
+
 		// We append to state before appending the pdu, so we don't have a moment in
 		// time with the pdu without it's state. This is okay because append_pdu can't
 		// fail.
 		self.services
 			.state
-			.set_event_state(&pdu.event_id, room_id, state_ids_compressed)
+			.set_event_state(&pdu.event_id, &room_id, state_ids_compressed)
 			.await?;

-		if soft_fail {
+		if should_soft_fail {
 			// Nothing else to do with a soft-failed event.
+			self.services
+				.pdu_metadata
+				.mark_event_soft_failed(pdu.event_id());
 			return Ok(None);
 		}

+		// Per https://spec.matrix.org/unstable/server-server-api/#soft-failure, soft-failed events
+		// are not added as forward extremities.
+		// This also means we set the state here.
+		// We do this BEFORE setting the extremities so that there's never a point in
+		// time where we have fresh extremities referencing stale state.
+		let mut extremities: Vec<_> = self
+			.services
+			.state
+			.get_forward_extremities(&room_id)
+			.collect()
+			.await;
+		extremities = self
+			.progress_state_and_extremities(
+				pdu,
+				room_version_rules,
+				state_before.clone(),
+				extremities,
+				state_lock,
+			)
+			.await?;
+
 		let pdu_id = self
-			.append_pdu(pdu, pdu_json, new_room_leaves, state_lock, room_id)
+			.append_pdu(
+				pdu,
+				pdu_json,
+				extremities.iter().map(Borrow::borrow),
+				state_lock,
+				&room_id,
+			)
 			.await?;

 		// Process admin commands for federation events
@@ -86,11 +130,110 @@ pub async fn append_incoming_pdu<'a, Leaves>(
 			}
 		}

-		self.services.sync.wake_all_joined(room_id).await;
+		self.services.sync.wake_all_joined(&room_id).await;

 		Ok(Some(pdu_id))
 	}

+	/// Derives new room state from the incoming event and filters forward
+	/// extremities accordingly. Does not set forward extremities.
+	///
+	/// Only call this function if the incoming PDU is not soft-failed or
+	/// rejected.
+	async fn progress_state_and_extremities(
+		&self,
+		incoming_pdu: &PduEvent,
+		room_version_rules: &RoomVersionRules,
+		state_before: HashMap<u64, OwnedEventId>,
+		forward_extremities: Vec<OwnedEventId>,
+		state_lock: &Guard<OwnedRoomId, ()>,
+	) -> Result<Vec<OwnedEventId>> {
+		if incoming_pdu.state_key().is_some() {
+			debug!("Event is a state-event. Deriving new room state");
+			self.derive_new_state(incoming_pdu, room_version_rules, state_before, state_lock)
+				.await?;
+		}
+
+		// Now we calculate the set of extremities this room has after the incoming
+		// event has been applied. We start with the previous extremities
+		trace!("Calculating extremities");
+		let mut forward_extremities = forward_extremities
+			.into_iter()
+			.stream()
+			.ready_filter(|event_id| {
+				// Remove any that are referenced by this incoming event's prev_events
+				!incoming_pdu.prev_events().any(is_equal_to!(event_id))
+			})
+			.broad_filter_map(|event_id| async move {
+				// Only keep those extremities were not referenced yet
+				self.services
+					.pdu_metadata
+					.is_event_referenced(&incoming_pdu.room_id_or_hash(), &event_id)
+					.await
+					.eq(&false)
+					.then_some(event_id)
+			})
+			.collect::<Vec<_>>()
+			.await;
+		forward_extremities.push(incoming_pdu.event_id().to_owned());
+		debug!(
+			"Retained {} extremities checked against {} prev_events",
+			forward_extremities.len(),
+			incoming_pdu.prev_events().count()
+		);
+		assert!(!forward_extremities.is_empty(), "resolved extremities cannot be empty");
+		Ok(forward_extremities)
+	}
+
+	/// Derives a new room state by adding the incoming PDU to the state before
+	/// it to create the state at, which then becomes the current room state.
+	///
+	/// The caller MUST ensure forward extremities are set appropriately,
+	/// including this incoming pdu, either before or after calling this
+	/// function. Failing to do so will result in an inconsistent current state
+	/// cache, which may affect event authentication.
+	async fn derive_new_state(
+		&self,
+		incoming_pdu: &PduEvent,
+		room_version_rules: &RoomVersionRules,
+		state_before: HashMap<u64, OwnedEventId>,
+		state_lock: &Guard<OwnedRoomId, ()>,
+	) -> Result {
+		let room_id = incoming_pdu.room_id_or_hash();
+		// We also add state after incoming event to the fork states
+		let mut state_at_incoming_event = state_before;
+		let shortstatekey = self
+			.services
+			.short
+			.get_or_create_shortstatekey(
+				&incoming_pdu.kind().to_string().into(),
+				incoming_pdu.state_key().unwrap(),
+			)
+			.await;
+
+		let event_id = incoming_pdu.event_id();
+		state_at_incoming_event.insert(shortstatekey, event_id.to_owned());
+
+		debug!("Resolving new room state");
+		let new_room_state = self
+			.services
+			.event_handler
+			.resolve_state(&room_id, room_version_rules, state_at_incoming_event)
+			.await?;
+
+		debug!("Forcing new room state");
+		let HashSetCompressStateEvent { shortstatehash, added, removed } = self
+			.services
+			.state_compressor
+			.save_state(&room_id, new_room_state)
+			.await?;
+
+		self.services
+			.state
+			.force_state(&room_id, shortstatehash, added, removed, state_lock)
+			.await
+	}
+
 	/// Populates the unsigned data of a PDU
 	async fn populate_unsigned(&self, pdu: &PduEvent, pdu_json: &mut CanonicalJsonObject) {
 		let Some(state_key) = pdu.state_key() else {
@@ -143,7 +143,7 @@ pub async fn get_remote_pdu(&self, room_id: &RoomId, event_id: &EventId) -> Resu
 				| Ok(value) => {
 					self.services
 						.event_handler
-						.handle_incoming_pdu(&backfill_server, room_id, event_id, value, false)
+						.handle_incoming_pdu(&backfill_server, room_id, event_id, value, true)
 						.boxed()
 						.await?;
 					debug!("Successfully backfilled {event_id} from {backfill_server}");
@@ -166,8 +166,11 @@ pub async fn get_remote_pdu(&self, room_id: &RoomId, event_id: &EventId) -> Resu
 	/// Backfills a single PDU.
 	#[tracing::instrument(skip(self, pdu), level = "debug")]
 	pub async fn backfill_pdu(&self, origin: &ServerName, pdu: Box<RawJsonValue>) -> Result<()> {
-		let (room_id, event_id, value) =
-			self.services.event_handler.parse_incoming_pdu(&pdu).await?;
+		let (room_id, event_id, value) = self
+			.services
+			.event_handler
+			.parse_incoming_pdu(&pdu, None)
+			.await?;

 		// Lock so we cannot backfill the same pdu twice at the same time
 		let mutex_lock = self
@@ -185,7 +188,7 @@ pub async fn backfill_pdu(&self, origin: &ServerName, pdu: Box<RawJsonValue>) ->

 		self.services
 			.event_handler
-			.handle_incoming_pdu(origin, &room_id, &event_id, value, false)
+			.handle_incoming_pdu(origin, &room_id, &event_id, value, true)
 			.boxed()
 			.await?;

@@ -22,7 +22,9 @@

 use super::RoomMutexGuard;

-pub fn pdu_fits(owned_obj: &mut CanonicalJsonObject) -> bool {
+/// Ensures the given PDU fits inside the size limits for a PDU.
+#[must_use]
+pub fn pdu_fits(owned_obj: &CanonicalJsonObject) -> bool {
 	// room IDs, event IDs, senders, types, and state keys must all be <= 255 bytes
 	if let Some(CanonicalJsonValue::String(room_id)) = owned_obj.get("room_id") {
 		if room_id.len() > 255 {
@@ -306,12 +308,27 @@ pub async fn create_hash_and_sign_event(
 				| _ => Err!(Request(Unknown(warn!("Signing event failed: {e}")))),
 			};
 		}
+
+		// Evil hack because only the PDU JSON gets signed
+		pdu.hashes = serde_json::from_value(serde_json::to_value(
+			pdu_json
+				.get("hashes")
+				.expect("must have hashes after signing")
+				.clone(),
+		)?)?;
+		pdu.signatures = serde_json::from_value(serde_json::to_value(
+			pdu_json
+				.get("signatures")
+				.expect("must have signatures after signing")
+				.clone(),
+		)?)?;
+
 		// Generate event id
 		pdu.event_id = gen_event_id(&pdu_json, &room_version_rules)?;
 		pdu_json
 			.insert("event_id".into(), CanonicalJsonValue::String(pdu.event_id.clone().into()));
 		// Verify that the *full* PDU isn't over 64KiB.
-		if !pdu_fits(&mut pdu_json.clone()) {
+		if !pdu_fits(&pdu_json.clone()) {
 			// feckin huge PDU mate
 			return Err!(Request(TooLarge("Message/PDU is too long (exceeds 65535 bytes)")));
 		}
@@ -77,6 +77,7 @@ struct Services {
 	short: Dep<rooms::short::Service>,
 	state: Dep<rooms::state::Service>,
 	state_accessor: Dep<rooms::state_accessor::Service>,
+	state_compressor: Dep<rooms::state_compressor::Service>,
 	state_cache: Dep<rooms::state_cache::Service>,
 	sync: Dep<sync::Service>,
 	threads: Dep<rooms::threads::Service>,
@@ -110,6 +111,8 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 				state: args.depend::<rooms::state::Service>("rooms::state"),
 				state_accessor: args
 					.depend::<rooms::state_accessor::Service>("rooms::state_accessor"),
+				state_compressor: args
+					.depend::<rooms::state_compressor::Service>("rooms::state_compressor"),
 				state_cache: args.depend::<rooms::state_cache::Service>("rooms::state_cache"),
 				sync: args.depend::<sync::Service>("sync"),
 				threads: args.depend::<rooms::threads::Service>("rooms::threads"),
@@ -65,17 +65,17 @@ pub(super) async fn for_local_user(services: &Services, user_id: &UserId) -> Sel
 	}

 	pub(super) fn for_device(
-		oauth_metadata: Option<&ClientMetadata>,
+		client_metadata: Option<&ClientMetadata>,
 		display_name: Option<&str>,
 	) -> Self {
-		let avatar_src = oauth_metadata
+		let avatar_src = client_metadata
 			.and_then(|metadata| metadata.logo_uri.as_ref())
 			.map(|uri| uri.as_str().to_owned());

 		let avatar_type = if let Some(avatar_src) = avatar_src {
 			AvatarType::Image(avatar_src)
 		} else if let Some(initial) = display_name.and_then(|name| name.chars().next()) {
-			if oauth_metadata.is_some() {
+			if client_metadata.is_some() {
 				AvatarType::Initial(initial)
 			} else {
 				AvatarType::Initial('❖')
@@ -86,6 +86,20 @@ pub(super) fn for_device(

 		Self { avatar_type }
 	}
+
+	pub(super) fn for_client(client_metadata: &ClientMetadata) -> Self {
+		let avatar_type = if let Some(logo) = &client_metadata.logo_uri {
+			AvatarType::Image(logo.to_string())
+		} else if let Some(name) = &client_metadata.client_name
+			&& let Some(char) = name.chars().next()
+		{
+			AvatarType::Initial(char)
+		} else {
+			AvatarType::Initial('?')
+		};
+
+		Self { avatar_type }
+	}
 }

 #[derive(Debug, Template)]
@@ -4,9 +4,12 @@
 	response::Redirect,
 	routing::on,
 };
-use conduwuit_service::oauth::grant::{AuthorizationCodeQuery, Prompt};
+use conduwuit_service::oauth::{
+	client_metadata::ClientMetadata,
+	grant::{AuthorizationCodeQuery, DeviceCodeVerifyQuery, Prompt},
+};
 use ruma::OwnedUserId;
-use url::Url;
+use serde::Deserialize;

 use crate::{
 	ROUTE_PREFIX, WebError,
@@ -14,7 +17,7 @@
 	pages::{
 		GET_POST, Result, TemplateContext,
 		account::register::{RegisterQuery, RequestedRegistrationFlow},
-		components::{Avatar, AvatarType, ClientScopes},
+		components::{Avatar, ClientScopes, UserCard},
 	},
 	response,
 	session::{LoginIntent, LoginQuery, LoginTarget, User},
@@ -22,7 +25,9 @@
 };

 pub(crate) fn build() -> Router<crate::State> {
-	Router::new().route("/authorization_code", on(GET_POST, route_authorization_code))
+	Router::new()
+		.route("/authorization_code", on(GET_POST, route_authorization_code))
+		.route("/device_code", on(GET_POST, route_device_code))
 }

 template! {
@@ -30,12 +35,9 @@ struct Grant use "grant.html.j2" {
 		logout_query: String,
 		user_id: OwnedUserId,
 		user_avatar: Avatar,
-		client_uri: Url,
-		client_name: String,
-		client_avatar: Avatar,
-		policy_uri: Option<Url>,
-		tos_uri: Option<Url>,
-		scopes: ClientScopes
+		client_metadata: ClientMetadata,
+		scopes: ClientScopes,
+		device_code: Option<String>
 	}
 }

@@ -102,27 +104,6 @@ async fn route_authorization_code(

 	let scopes = query.scope.to_scopes().map_err(WebError::BadRequest)?;

-	let client_name = if let Some(name) = &client.client_name {
-		name
-	} else {
-		"Unknown application"
-	}
-	.to_owned();
-
-	let client_avatar = {
-		let avatar_type = if let Some(logo) = &client.logo_uri {
-			AvatarType::Image(logo.to_string())
-		} else if let Some(name) = &client.client_name
-			&& let Some(char) = name.chars().next()
-		{
-			AvatarType::Initial(char)
-		} else {
-			AvatarType::Initial('?')
-		};
-
-		Avatar { avatar_type }
-	};
-
 	let user_avatar = Avatar::for_local_user(&services, &user_id).await;

 	response!(Grant::new(
@@ -135,11 +116,102 @@ async fn route_authorization_code(
 		.unwrap(),
 		user_id,
 		user_avatar,
-		client.client_uri.clone(),
-		client_name,
-		client_avatar,
-		client.policy_uri.clone(),
-		client.tos_uri.clone(),
+		client,
 		ClientScopes { scopes },
+		None,
 	))
 }
+
+#[derive(Deserialize)]
+#[serde(tag = "stage", rename_all = "snake_case")]
+enum DeviceCodeForm {
+	Lookup {
+		user_code: String,
+	},
+	Confirm {
+		device_code: String,
+	},
+}
+
+template! {
+	struct DeviceCodeGrant use "device_code_grant.html.j2" {
+		user_card: UserCard,
+		body: DeviceCodeGrantBody
+	}
+}
+
+#[derive(Debug)]
+enum DeviceCodeGrantBody {
+	Lookup {
+		user_code_error: bool,
+	},
+	Success,
+}
+
+async fn route_device_code(
+	State(services): State<crate::State>,
+	Extension(context): Extension<TemplateContext>,
+	user: User<true>,
+	Expect(Query(query)): Expect<Query<DeviceCodeVerifyQuery>>,
+	PostForm(form): PostForm<DeviceCodeForm>,
+) -> Result {
+	let user_id = if let Some(user) = user.into_session() {
+		user.user_id
+	} else {
+		let next = LoginTarget::DeviceCode(query.clone());
+
+		let uri = format!(
+			"{}/account/login?{}",
+			ROUTE_PREFIX,
+			serde_urlencoded::to_string(LoginQuery { next: Some(next), ..Default::default() })
+				.unwrap()
+		);
+
+		return response!(Redirect::to(&uri));
+	};
+
+	let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+
+	match (form, query.user_code.clone()) {
+		| (None, Some(user_code)) | (Some(DeviceCodeForm::Lookup { user_code }), _) => {
+			let Some(grant_info) = services.oauth.grant_info_for_user_code(&user_code).await
+			else {
+				return response!(DeviceCodeGrant::new(
+					context,
+					user_card,
+					DeviceCodeGrantBody::Lookup { user_code_error: true }
+				));
+			};
+
+			let user_avatar = Avatar::for_local_user(&services, &user_id).await;
+
+			response!(Grant::new(
+				context,
+				serde_urlencoded::to_string(LoginQuery {
+					next: Some(LoginTarget::DeviceCode(query)),
+					intent: Some(LoginIntent::SwitchAccounts),
+					..Default::default()
+				})
+				.unwrap(),
+				user_id,
+				user_avatar,
+				grant_info.client_metadata,
+				ClientScopes { scopes: grant_info.requested_scopes },
+				Some(grant_info.device_code),
+			))
+		},
+		| (Some(DeviceCodeForm::Confirm { device_code }), _) => {
+			services
+				.oauth
+				.validate_device_code(user_id, &device_code)
+				.await
+				.map_err(WebError::BadRequest)?;
+
+			response!(DeviceCodeGrant::new(context, user_card, DeviceCodeGrantBody::Success))
+		},
+		| (None, None) =>
+			response!(DeviceCodeGrant::new(context, user_card, DeviceCodeGrantBody::Lookup {
+				user_code_error: false
+			})),
+	}
+}
@@ -6,9 +6,12 @@
 	response::Redirect,
 	routing::on,
 };
-use conduwuit_service::{oauth::grant::AuthorizationCodeResponse, oidc::SessionCompletionStatus};
+use conduwuit_service::{
+	oauth::grant::AuthorizationCodeResponse,
+	oidc::{ClaimedLocalUser, SessionCompletionStatus},
+};
 use futures::FutureExt;
-use ruma::{OwnedServerName, UserId};
+use ruma::OwnedServerName;
 use serde::{Deserialize, de::IgnoredAny};
 use tower_sessions::Session;

@@ -99,65 +102,60 @@ async fn route_complete(
 					state: OidcSessionState::Authorized { claims: Box::new(claims.clone()) },
 				})
 				.await
-				.expect("Should be able to serialize oidc session");
+				.expect("should be able to serialize oidc session");

 			services.oidc.complete_session(&claims, None).await
 		},
 		| OidcSessionState::Authorized { claims } => {
 			let supplied_user_id = if let Some(form) = form {
-				if let Ok(user_id) = UserId::parse(format!(
-					"@{}:{}",
-					form.username,
-					services.globals.server_name()
-				)) && services.users.status(&user_id).await.is_active()
+				match services
+					.oidc
+					.identify_claimed_local_user(&form.username)
+					.await
 				{
-					let user_card = UserCard::for_local_user(&services, user_id.clone()).await;
+					| Ok(ClaimedLocalUser::Existing(user_id)) => {
+						let user_card =
+							UserCard::for_local_user(&services, user_id.clone()).await;

-					if let Some(password) = form.password {
-						if services
-							.users
-							.check_password(&user_id, &password)
-							.await
-							.is_ok()
-						{
-							Some(user_id)
+						if let Some(password) = form.password {
+							if services
+								.users
+								.check_password(&user_id, &password)
+								.await
+								.is_ok()
+							{
+								Some(user_id)
+							} else {
+								return response!(OidcComplete::new(
+									context,
+									OidcCompleteBody::PasswordPrompt {
+										username: form.username,
+										user_card,
+										password_error: true
+									}
+								));
+							}
 						} else {
 							return response!(OidcComplete::new(
 								context,
 								OidcCompleteBody::PasswordPrompt {
 									username: form.username,
 									user_card,
-									password_error: true
+									password_error: false,
 								}
 							));
 						}
-					} else {
+					},
+					| Ok(ClaimedLocalUser::New(user_id)) => Some(user_id),
+					| Err(err) => {
 						return response!(OidcComplete::new(
 							context,
-							OidcCompleteBody::PasswordPrompt {
-								username: form.username,
-								user_card,
-								password_error: false,
+							OidcCompleteBody::UsernamePrompt {
+								server_name: services.globals.server_name().to_owned(),
+								username_error: Some(err.message()),
 							}
 						));
-					}
-				} else {
-					match services
-						.users
-						.determine_registration_user_id(Some(form.username), None, None)
-						.await
-					{
-						| Ok(user_id) => Some(user_id),
-						| Err(err) => {
-							return response!(OidcComplete::new(
-								context,
-								OidcCompleteBody::UsernamePrompt {
-									server_name: services.globals.server_name().to_owned(),
-									username_error: Some(err.message()),
-								}
-							));
-						},
-					}
+					},
 				}
 			} else {
 				None
@@ -20,3 +20,17 @@
    font-style: italic;
    text-align: center;
 }
+
+.user-code {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+
+    input {
+        text-align: center;
+        font-weight: bold;
+        font-size: 200%;
+        padding: 0.2em;
+        width: 6em !important;
+    }
+}
@@ -0,0 +1,50 @@
+{% extends "_layout.html.j2" %}
+
+{%- block head -%}
+<link rel="stylesheet" href="{{ crate::ROUTE_PREFIX }}/resources/grant.css">
+{%- endblock -%}
+
+{%- block title -%}
+Authorize client
+{%- endblock -%}
+
+{%- block content -%}
+<div class="panel narrow">
+    <h1>Authorize device</h1>
+    {{ user_card }}
+    {% match body %}
+        {% when DeviceCodeGrantBody::Lookup { user_code_error }  %}
+            <p>
+                Enter the code displayed on your device, or in the app you're signing into.
+            </p>
+            <p>
+                <em class="negative">Never enter a code given to you by someone else.</em>
+                Your homeserver administrator will never ask you to enter a code on this page.
+            </p>
+
+            <form method="post">
+                <p>
+                    <div class="user-code">
+                        <label for="user_code">Validation code</label>
+                        <input
+                            type="text"
+                            id="user_code"
+                            name="user_code"
+                            maxlength="6"
+                            spellcheck="false"
+                            pattern="\d{6}"
+                            title="Enter the six-digit validation code"
+                        >
+                    </div>
+                    {% if user_code_error %}
+                        <small class="error">Invalid code</small>
+                    {% endif %}
+                </p>
+                <input type="hidden" name="stage" value="lookup">
+                <button type="submit">Continue</button>
+            </form>
+        {% when DeviceCodeGrantBody::Success %}
+            <p>Success! 🎉 You can close this tab and return to your device.</p>
+    {% endmatch %}
+</div>
+{% endblock %}
@@ -9,6 +9,7 @@ Authorize client
 {%- endblock -%}

 {%- block content -%}
+{% let client_name = client_metadata.client_name.as_deref().unwrap_or("Unknown application") %}
 <div class="panel narrow">
    <h1>Authorize {{ client_name }}</h1>
    <div class="avatars">
@@ -18,17 +19,17 @@ Authorize client
        <div class="separator" aria-hidden="true">
            ⇄
        </div>
-        {{ client_avatar }}
+        {{ Avatar::for_client(client_metadata) }}
    </div>
    <div class="identity">
        Signed in as <code>{{ user_id }}</code>. <a href="{{ crate::ROUTE_PREFIX }}/account/logout?{{ logout_query }}">Switch accounts</a>
    </div>
    <p>
-        <b>{{ client_name }}</b> (<a href="{{ client_uri }}">{{ client_uri.domain().unwrap() }}</a>) would like
+        <b>{{ client_name }}</b> (<a href="{{ client_metadata.client_uri }}">{{ client_metadata.client_uri.domain().unwrap() }}</a>) would like
        your permission to:
        {{ scopes }}
    </p>
-    {% match (&policy_uri, &tos_uri) %}
+    {% match (&client_metadata.policy_uri, &client_metadata.tos_uri) %}
        {% when (Some(policy_uri), Some(tos_uri)) %}
            <p>
                {{ client_name }}'s <a href="{{ policy_uri }}">policies</a>
@@ -49,6 +50,10 @@ Authorize client
    {% endmatch %}

    <form method="post">
+        <input type="hidden" name="stage" value="confirm">
+        {% if let Some(device_code) = device_code %}
+            <input type="hidden" name="device_code" value="{{ device_code }}">
+        {% endif %}
        <button type="submit">Continue</button>
    </form>
 </div>
@@ -9,7 +9,7 @@
 	http::request::Parts,
 	response::{IntoResponse, Redirect, Response},
 };
-use conduwuit_service::oauth::grant::AuthorizationCodeQuery;
+use conduwuit_service::oauth::grant::{AuthorizationCodeQuery, DeviceCodeVerifyQuery};
 use ruma::{OwnedUserId, UserId};
 use serde::{Deserialize, Serialize};
 use tower_sessions::Session;
@@ -38,6 +38,7 @@ pub(crate) enum LoginTarget {
 	ChangeEmail,
 	CrossSigningReset,
 	Deactivate,
+	DeviceCode(DeviceCodeVerifyQuery),
 	DeviceInfo(DevicePath),
 	RemoveDevice(DevicePath),
 }
@@ -59,6 +60,9 @@ pub(crate) fn target_path(&self) -> String {
 			| Self::ChangeEmail => "account/email/change/".into(),
 			| Self::CrossSigningReset => "account/cross_signing_reset".into(),
 			| Self::Deactivate => "account/deactivate".into(),
+			| Self::DeviceCode(code) =>
+				format!("oauth2/grant/device_code?{}", serde_urlencoded::to_string(code).unwrap())
+					.into(),
 			| Self::DeviceInfo(path) => format!("account/device/{}/", path.device).into(),
 			| Self::RemoveDevice(path) => format!("account/device/{}/remove", path.device).into(),
 		};
Author	SHA1	Message	Date
Ginger	64189263ba	fix: Use correct error code for invalid client ID	2026-07-13 10:01:50 -04:00
Ginger	14b8333183	feat: Add support for OAuth2 device auth flow	2026-07-12 17:32:13 -04:00
Ginger	9a94b93ddd	fix: Fix new database migrations running on every server startup	2026-07-12 12:31:12 -04:00
Gingerandtimedout	0ac0bd93ae	fix: Default deserialize for `compatibility_mode`	2026-07-12 16:28:27 +01:00
Gingerandtimedout	fe9f718c6e	fix: Stop using the federation DNS resolver for non-federation requests	2026-07-12 16:11:00 +01:00
nexandEllis Git	e333f5a8e5	chore: announce	2026-07-12 04:14:23 +00:00
Ginger	b8c64a68d4	chore: Release	2026-07-12 00:09:26 -04:00
Ginger	163f049757	chore: Update changelog	2026-07-12 00:07:20 -04:00
Ginger	f48125c37a	fix: Remove dependency on aws-lc-rs	2026-07-11 22:48:30 -04:00
timedoutandEllis Git	4001b99261	style: Make send_join's docstring more useful	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	b6e5a106ff	fix: Don't unhelpfully panic when encountering an unrecognised room version	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	e1eea45fd6	style: Fix EOL	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	7cb53f41d6	chore: Add newsfrag	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	fbf81fcdeb	fix: Opportunistically re-use room format rules when parsing incoming PDUs	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	87030a3a22	fix: Ensure PDU returned by `create_hash_and_sign_event` is itself signed	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	4f509fa113	fix: Convert room summary to federation format when sending invites	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	aa7ed885c0	fix: Check correct field name when determining event type	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	d5e6e617d1	fix: Remove redundant banned room server checks These don't make sense here anyway	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	1f7680ad5f	feat: Give send_join the invite treatment	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	0c37a542d4	feat: Give send_leave the invite treatment	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	efd07da0d7	feat: Give send_knock the invite treatment	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	f0590e882a	fix: Only run ACL checks when we know we have live state Prevents a potential bug where we might inadvertently reject valid invites because we have a stale state cache that blocks the sender or even ourselves Also fixes the banned remote server room check by using the create event instead of room ID	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	7225bf25ae	feat: Persist create events received during the invite process	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	e52bb5db69	style: Move invite validation into own functions	2026-07-12 02:11:50 +00:00
timedoutandEllis Git	995726923b	feat: Enforce new federation invite checks These were introduced in spec v1.16 however we didn't implement them until now for compatibility.	2026-07-12 02:11:50 +00:00
GingerandEllis Git	556141b404	fix: Trim whitespace from OIDC client secret file	2026-07-12 02:06:48 +00:00
Henry-HilesandEllis Git	6858e1b893	fix: fallback rev to empty string Fixes flake-compat support	2026-07-11 20:13:58 +00:00
GingerandEllis Git	07e241f616	chore: News fragment	2026-07-11 19:40:25 +00:00
GingerandEllis Git	cfbe590f1c	fix: Do not require an access token on 3pid token request route	2026-07-11 19:40:25 +00:00
GingerandEllis Git	d9c2f04d73	fix: Correctly handle preferred_username claim	2026-07-11 19:21:33 +00:00
GingerandEllis Git	ada0b3184b	fix: Properly sync newly created rooms	2026-07-11 19:21:19 +00:00
Renovate BotandEllis Git	1d6ad485f6	chore(deps): update ruma digest to 9b6a2e7	2026-07-11 16:29:54 +00:00
timedout	9d2ce72f73	style: Remove redundant length check for dag build	2026-07-11 17:27:42 +01:00
timedout	13bcb5af13	style: Accept event id reference in `pdu_format_check_1`	2026-07-11 17:27:42 +01:00
timedout	5868510df1	fix: Remove redundant "correct room ID" filter	2026-07-11 17:27:42 +01:00
timedout	c34d1fe76e	feat: Move PDU validation out of parsing and into check 1	2026-07-11 17:27:42 +01:00
timedout	838764b0ac	style: Remove needless async def for `parse_incoming_pdu_with_known_room`	2026-07-11 17:27:42 +01:00
timedout	b51a34c1c1	fix: Address review feedback	2026-07-11 17:27:42 +01:00
timedout	2fbb779d12	fix: Invert boolean returned by policy server check	2026-07-11 17:27:42 +01:00
timedout	e16a62e1ed	feat: Add more debug logging to PDU handle funcs Tracking down weird soft-fails	2026-07-11 17:27:42 +01:00
timedout	64a08262ca	perf: Change signature of `build_local_dag` to remove refmap hacks	2026-07-11 17:27:42 +01:00
timedout	70a3905761	style: Remove duplicate pdu check 1 call in handle_incoming_pdu	2026-07-11 17:27:42 +01:00
timedout	cf9179e8f6	fix: Perform checks 1-3 on auth chain PDUs	2026-07-11 17:27:42 +01:00
timedout	6b899b7f80	refactor: Move PDU checks 1, 2, and 3 into pdu_checks.rs	2026-07-11 17:27:42 +01:00
timedout	ad57fa06fc	style: Unify and document `state_before_incoming`	2026-07-11 17:27:42 +01:00
timedout	ec9efbada5	fix: Don't reject auth events when they're innocent in auth chain response	2026-07-11 17:27:42 +01:00
timedout	318d2b205a	style: Move PDU check functions into their own module	2026-07-11 17:27:42 +01:00
timedout	99a5f2a9fb	refactor: Reduce complexity of incoming PDU handling * Ignores any events pushed without a room ID * Removes needless clones for PDU size checking * Removes incorrect ACL check in incoming handler * Fast-path handling already handled outlier events * Remove redundant same-room checks, replace with useful ones * Combine event rejection and persistence in a single function * Additional safety assertions in upgrade task * Split upgrade task into multiple subroutines for reduced cognitive complexity * Only mutate current state and forward extremities in tandem * Improve code documentation to better explain the logic flow	2026-07-11 17:27:42 +01:00
Renovate BotandEllis Git	ace0d52074	chore(deps): Update rust crate termimad to 0.35.0	2026-07-11 15:35:53 +00:00
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				`Added support for the OAuth2 device authorization flow. Contributed by @ginger`
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				Fixed `global.oauth.compatibility_mode` being required, despite being ignored, when the `[global.oauth.oidc]` config section is provided.
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				Fixed an issue with a migration that could cause user accounts imported from an identity provider to be marked as deactivated when the server started. If you have accounts affected by this issue, use `!admin users reset-password --convert-to-local-account` to reactivate them.
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				`Stopped appservice users from being erroneously marked as deactivated during a 26.6 database migration.`