chore: Release

Reviewed-By: timedout <git@nexy7574.co.uk>

Cargo.lock

@@ -887,7 +887,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "clap",
  "conduwuit_admin",
@@ -919,7 +919,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_admin"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "clap",
  "conduwuit_api",
@@ -940,7 +940,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_api"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "async-trait",
  "axum",
@@ -972,14 +972,14 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_build_metadata"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "built",
 ]
 
 [[package]]
 name = "conduwuit_core"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "argon2",
  "arrayvec",
@@ -1041,7 +1041,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_database"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "async-channel",
  "conduwuit_core",
@@ -1059,7 +1059,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_macros"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "itertools 0.14.0",
  "proc-macro2",
@@ -1069,7 +1069,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_router"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "axum",
  "axum-client-ip",
@@ -1103,7 +1103,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_service"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "askama",
  "async-trait",
@@ -1145,7 +1145,7 @@ dependencies = [
 
 [[package]]
 name = "conduwuit_web"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "askama",
  "axum",
@@ -4055,12 +4055,14 @@ dependencies = [
  "sync_wrapper",
  "tokio",
  "tokio-rustls",
+ "tokio-util",
  "tower",
  "tower-http",
  "tower-service",
  "url",
  "wasm-bindgen",
  "wasm-bindgen-futures",
+ "wasm-streams",
  "web-sys",
  "webpki-roots",
 ]
@@ -5868,6 +5870,19 @@ dependencies = [
  "wasmparser",
 ]
 
+[[package]]
+name = "wasm-streams"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "15053d8d85c7eccdbefef60f06769760a563c7f0a9d6902a13d35c7800b0ad65"
+dependencies = [
+ "futures-util",
+ "js-sys",
+ "wasm-bindgen",
+ "wasm-bindgen-futures",
+ "web-sys",
+]
+
 [[package]]
 name = "wasmparser"
 version = "0.244.0"
@@ -6332,7 +6347,7 @@ dependencies = [
 
 [[package]]
 name = "xtask"
-version = "0.5.5"
+version = "0.5.6-alpha"
 dependencies = [
  "askama",
  "cargo_metadata",

Cargo.toml

@@ -12,7 +12,7 @@ license = "Apache-2.0"
 # See also `rust-toolchain.toml`
 readme = "README.md"
 repository = "https://forgejo.ellis.link/continuwuation/continuwuity"
-version = "0.5.5"
+version = "0.5.6-alpha"
 
 [workspace.metadata.crane]
 name = "conduwuit"
@@ -144,6 +144,7 @@ features = [
     "socks",
     "hickory-dns",
     "http2",
+    "stream",
 ]
 
 [workspace.dependencies.serde]
@@ -363,6 +364,7 @@ features = [
     "unstable-msc2870",
     "unstable-msc3026",
     "unstable-msc3061",
+    "unstable-msc3814",
     "unstable-msc3245",
     "unstable-msc3266",
     "unstable-msc3381", # polls

changelog.d/1436.feature.md

@@ -0,0 +1 @@
+Added MSC3814 Dehydrated Devices - you can now decrypt messages sent while all devices were logged out.

clippy.toml

@@ -15,6 +15,18 @@ disallowed-macros = [
 	{ path = "log::trace", reason = "use conduwuit_core::trace" },
 ]
 
-disallowed-methods = [
-    { path = "tokio::spawn", reason = "use and pass conduuwit_core::server::Server::runtime() to spawn from" },
-]
+[[disallowed-methods]]
+path = "tokio::spawn"
+reason = "use and pass conduwuit_core::server::Server::runtime() to spawn from"
+
+[[disallowed-methods]]
+path = "reqwest::Response::bytes"
+reason = "bytes is unsafe, use limit_read via the conduwuit_core::utils::LimitReadExt trait instead"
+
+[[disallowed-methods]]
+path = "reqwest::Response::text"
+reason = "text is unsafe, use limit_read_text via the conduwuit_core::utils::LimitReadExt trait instead"
+
+[[disallowed-methods]]
+path = "reqwest::Response::json"
+reason = "json is unsafe, use limit_read_text via the conduwuit_core::utils::LimitReadExt trait instead"

docker/Dockerfile

@@ -180,6 +180,11 @@ RUN --mount=type=cache,target=/usr/local/cargo/registry \
         export RUSTFLAGS="${RUSTFLAGS}"
     fi
 
+    RUST_PROFILE_DIR="${RUST_PROFILE}"
+    if [[ "${RUST_PROFILE}" == "dev" ]]; then
+        RUST_PROFILE_DIR="debug"
+    fi
+
     TARGET_DIR=($(cargo metadata --no-deps --format-version 1 | \
             jq -r ".target_directory"))
     mkdir /out/sbin
@@ -191,8 +196,8 @@ RUN --mount=type=cache,target=/usr/local/cargo/registry \
         jq -r ".packages[] | select(.name == \"$PACKAGE\") | .targets[] | select( .kind | map(. == \"bin\") | any ) | .name"))
     for BINARY in "${BINARIES[@]}"; do
         echo $BINARY
-        xx-verify $TARGET_DIR/$(xx-cargo --print-target-triple)/${RUST_PROFILE}/$BINARY
-        cp $TARGET_DIR/$(xx-cargo --print-target-triple)/${RUST_PROFILE}/$BINARY /out/sbin/$BINARY
+        xx-verify $TARGET_DIR/$(xx-cargo --print-target-triple)/${RUST_PROFILE_DIR}/$BINARY
+        cp $TARGET_DIR/$(xx-cargo --print-target-triple)/${RUST_PROFILE_DIR}/$BINARY /out/sbin/$BINARY
     done
 EOF
 

src/admin/federation/commands.rs

@@ -1,6 +1,6 @@
 use std::fmt::Write;
 
-use conduwuit::{Err, Result};
+use conduwuit::{Err, Result, utils::response::LimitReadExt};
 use futures::StreamExt;
 use ruma::{OwnedRoomId, OwnedServerName, OwnedUserId};
 
@@ -55,7 +55,15 @@ pub(super) async fn fetch_support_well_known(&self, server_name: OwnedServerName
 		.send()
 		.await?;
 
-	let text = response.text().await?;
+	let text = response
+		.limit_read_text(
+			self.services
+				.config
+				.max_request_size
+				.try_into()
+				.expect("u64 fits into usize"),
+		)
+		.await?;
 
 	if text.is_empty() {
 		return Err!("Response text/body is empty.");

src/api/client/dehydrated_device.rs

@@ -0,0 +1,121 @@
+use axum::extract::State;
+use axum_client_ip::InsecureClientIp;
+use conduwuit::{Err, Result, at};
+use futures::StreamExt;
+use ruma::api::client::dehydrated_device::{
+	delete_dehydrated_device::unstable as delete_dehydrated_device,
+	get_dehydrated_device::unstable as get_dehydrated_device, get_events::unstable as get_events,
+	put_dehydrated_device::unstable as put_dehydrated_device,
+};
+
+use crate::Ruma;
+
+const MAX_BATCH_EVENTS: usize = 50;
+
+/// # `PUT /_matrix/client/../dehydrated_device`
+///
+/// Creates or overwrites the user's dehydrated device.
+#[tracing::instrument(skip_all, fields(%client))]
+pub(crate) async fn put_dehydrated_device_route(
+	State(services): State<crate::State>,
+	InsecureClientIp(client): InsecureClientIp,
+	body: Ruma<put_dehydrated_device::Request>,
+) -> Result<put_dehydrated_device::Response> {
+	let sender_user = body
+		.sender_user
+		.as_deref()
+		.expect("AccessToken authentication required");
+
+	let device_id = body.body.device_id.clone();
+
+	services
+		.users
+		.set_dehydrated_device(sender_user, body.body)
+		.await?;
+
+	Ok(put_dehydrated_device::Response { device_id })
+}
+
+/// # `DELETE /_matrix/client/../dehydrated_device`
+///
+/// Deletes the user's dehydrated device without replacement.
+#[tracing::instrument(skip_all, fields(%client))]
+pub(crate) async fn delete_dehydrated_device_route(
+	State(services): State<crate::State>,
+	InsecureClientIp(client): InsecureClientIp,
+	body: Ruma<delete_dehydrated_device::Request>,
+) -> Result<delete_dehydrated_device::Response> {
+	let sender_user = body.sender_user();
+
+	let device_id = services.users.get_dehydrated_device_id(sender_user).await?;
+
+	services.users.remove_device(sender_user, &device_id).await;
+
+	Ok(delete_dehydrated_device::Response { device_id })
+}
+
+/// # `GET /_matrix/client/../dehydrated_device`
+///
+/// Gets the user's dehydrated device
+#[tracing::instrument(skip_all, fields(%client))]
+pub(crate) async fn get_dehydrated_device_route(
+	State(services): State<crate::State>,
+	InsecureClientIp(client): InsecureClientIp,
+	body: Ruma<get_dehydrated_device::Request>,
+) -> Result<get_dehydrated_device::Response> {
+	let sender_user = body.sender_user();
+
+	let device = services.users.get_dehydrated_device(sender_user).await?;
+
+	Ok(get_dehydrated_device::Response {
+		device_id: device.device_id,
+		device_data: device.device_data,
+	})
+}
+
+/// # `GET /_matrix/client/../dehydrated_device/{device_id}/events`
+///
+/// Paginates the events of the dehydrated device.
+#[tracing::instrument(skip_all, fields(%client))]
+pub(crate) async fn get_dehydrated_events_route(
+	State(services): State<crate::State>,
+	InsecureClientIp(client): InsecureClientIp,
+	body: Ruma<get_events::Request>,
+) -> Result<get_events::Response> {
+	let sender_user = body.sender_user();
+
+	let device_id = &body.body.device_id;
+	let existing_id = services.users.get_dehydrated_device_id(sender_user).await;
+
+	if existing_id.as_ref().is_err()
+		|| existing_id
+			.as_ref()
+			.is_ok_and(|existing_id| existing_id != device_id)
+	{
+		return Err!(Request(Forbidden("Not the dehydrated device_id.")));
+	}
+
+	let since: Option<u64> = body
+		.body
+		.next_batch
+		.as_deref()
+		.map(str::parse)
+		.transpose()?;
+
+	let mut next_batch: Option<u64> = None;
+	let events = services
+		.users
+		.get_to_device_events(sender_user, device_id, since, None)
+		.take(MAX_BATCH_EVENTS)
+		.inspect(|&(count, _)| {
+			next_batch.replace(count);
+		})
+		.map(at!(1))
+		.collect()
+		.await;
+
+	Ok(get_events::Response {
+		events,
+		next_batch: next_batch.as_ref().map(ToString::to_string),
+	})
+}

src/api/client/mod.rs

@@ -6,6 +6,7 @@
 pub(super) mod backup;
 pub(super) mod capabilities;
 pub(super) mod context;
+pub(super) mod dehydrated_device;
 pub(super) mod device;
 pub(super) mod directory;
 pub(super) mod filter;
@@ -49,6 +50,7 @@
 pub(super) use backup::*;
 pub(super) use capabilities::*;
 pub(super) use context::*;
+pub(super) use dehydrated_device::*;
 pub(super) use device::*;
 pub(super) use directory::*;
 pub(super) use filter::*;

src/api/client/sync/v3/mod.rs

@@ -11,7 +11,7 @@
 use axum::extract::State;
 use axum_client_ip::InsecureClientIp;
 use conduwuit::{
-	Result, extract_variant,
+	Result, at, extract_variant,
 	utils::{
 		ReadyExt, TryFutureExtExt,
 		stream::{BroadbandExt, Tools, WidebandExt},
@@ -385,6 +385,7 @@ pub(crate) async fn build_sync_events(
 			last_sync_end_count,
 			Some(current_count),
 		)
+		.map(at!(1))
 		.collect::<Vec<_>>();
 
 	let device_one_time_keys_count = services

src/api/client/sync/v5.rs

@@ -1029,6 +1029,7 @@ async fn collect_to_device(
 		events: services
 			.users
 			.get_to_device_events(sender_user, sender_device, None, Some(next_batch))
+			.map(at!(1))
 			.collect()
 			.await,
 	})

src/api/client/unversioned.rs

@@ -50,6 +50,7 @@ pub(crate) async fn get_supported_versions_route(
 			("org.matrix.msc2836".to_owned(), true), /* threading/threads (https://github.com/matrix-org/matrix-spec-proposals/pull/2836) */
 			("org.matrix.msc2946".to_owned(), true), /* spaces/hierarchy summaries (https://github.com/matrix-org/matrix-spec-proposals/pull/2946) */
 			("org.matrix.msc3026.busy_presence".to_owned(), true), /* busy presence status (https://github.com/matrix-org/matrix-spec-proposals/pull/3026) */
+			("org.matrix.msc3814".to_owned(), true),               /* dehydrated devices */
 			("org.matrix.msc3827".to_owned(), true), /* filtering of /publicRooms by room type (https://github.com/matrix-org/matrix-spec-proposals/pull/3827) */
 			("org.matrix.msc3952_intentional_mentions".to_owned(), true), /* intentional mentions (https://github.com/matrix-org/matrix-spec-proposals/pull/3952) */
 			("org.matrix.msc3916.stable".to_owned(), true), /* authenticated media (https://github.com/matrix-org/matrix-spec-proposals/pull/3916) */

src/api/router.rs

@@ -160,6 +160,10 @@ pub fn build(router: Router<State>, server: &Server) -> Router<State> {
 		.ruma_route(&client::update_device_route)
 		.ruma_route(&client::delete_device_route)
 		.ruma_route(&client::delete_devices_route)
+		.ruma_route(&client::put_dehydrated_device_route)
+		.ruma_route(&client::delete_dehydrated_device_route)
+		.ruma_route(&client::get_dehydrated_device_route)
+		.ruma_route(&client::get_dehydrated_events_route)
 		.ruma_route(&client::get_tags_route)
 		.ruma_route(&client::update_tag_route)
 		.ruma_route(&client::delete_tag_route)

src/core/utils/mod.rs

@@ -11,6 +11,7 @@
 pub mod math;
 pub mod mutex_map;
 pub mod rand;
+pub mod response;
 pub mod result;
 pub mod set;
 pub mod stream;

src/core/utils/response.rs

@@ -0,0 +1,51 @@
+use futures::StreamExt;
+use num_traits::ToPrimitive;
+
+use crate::Err;
+
+/// Reads the response body while enforcing a maximum size limit to prevent
+/// memory exhaustion.
+pub async fn limit_read(response: reqwest::Response, max_size: u64) -> crate::Result<Vec<u8>> {
+	if response.content_length().is_some_and(|len| len > max_size) {
+		return Err!(BadServerResponse("Response too large"));
+	}
+	let mut data = Vec::new();
+	let mut reader = response.bytes_stream();
+
+	while let Some(chunk) = reader.next().await {
+		let chunk = chunk?;
+		data.extend_from_slice(&chunk);
+
+		if data.len() > max_size.to_usize().expect("max_size must fit in usize") {
+			return Err!(BadServerResponse("Response too large"));
+		}
+	}
+
+	Ok(data)
+}
+
+/// Reads the response body as text while enforcing a maximum size limit to
+/// prevent memory exhaustion.
+pub async fn limit_read_text(
+	response: reqwest::Response,
+	max_size: u64,
+) -> crate::Result<String> {
+	let text = String::from_utf8(limit_read(response, max_size).await?)?;
+	Ok(text)
+}
+
+#[allow(async_fn_in_trait)]
+pub trait LimitReadExt {
+	async fn limit_read(self, max_size: u64) -> crate::Result<Vec<u8>>;
+	async fn limit_read_text(self, max_size: u64) -> crate::Result<String>;
+}
+
+impl LimitReadExt for reqwest::Response {
+	async fn limit_read(self, max_size: u64) -> crate::Result<Vec<u8>> {
+		limit_read(self, max_size).await
+	}
+
+	async fn limit_read_text(self, max_size: u64) -> crate::Result<String> {
+		limit_read_text(self, max_size).await
+	}
+}

src/database/maps.rs

@@ -362,6 +362,10 @@ pub(super) fn open_list(db: &Arc<Engine>, maps: &[Descriptor]) -> Result<Maps> {
 		name: "userid_blurhash",
 		..descriptor::RANDOM_SMALL
 	},
+	Descriptor {
+		name: "userid_dehydrateddevice",
+		..descriptor::RANDOM_SMALL
+	},
 	Descriptor {
 		name: "userid_devicelistversion",
 		..descriptor::RANDOM_SMALL

src/service/admin/mod.rs

@@ -530,7 +530,12 @@ async fn handle_response_error(
 		Ok(())
 	}
 
-	pub async fn is_admin_command<E>(&self, event: &E, body: &str) -> Option<InvocationSource>
+	pub async fn is_admin_command<E>(
+		&self,
+		event: &E,
+		body: &str,
+		sent_locally: bool,
+	) -> Option<InvocationSource>
 	where
 		E: Event + Send + Sync,
 	{
@@ -580,6 +585,15 @@ pub async fn is_admin_command<E>(&self, event: &E, body: &str) -> Option<Invocat
 				return None;
 			}
 
+			// Escaped commands must be sent locally (via client API), not via federation
+			if !sent_locally {
+				conduwuit::warn!(
+					"Ignoring escaped admin command from {} that arrived via federation",
+					event.sender()
+				);
+				return None;
+			}
+
 			// Looks good
 			Some(InvocationSource::EscapedCommand)
 		}

src/service/announcements/mod.rs

@@ -18,7 +18,7 @@
 use std::{sync::Arc, time::Duration};
 
 use async_trait::async_trait;
-use conduwuit::{Result, Server, debug, error, warn};
+use conduwuit::{Result, Server, debug, error, utils::response::LimitReadExt, warn};
 use database::{Deserialized, Map};
 use ruma::events::{Mentions, room::message::RoomMessageEventContent};
 use serde::Deserialize;
@@ -137,7 +137,7 @@ async fn check(&self) -> Result<()> {
 			.get(CHECK_FOR_ANNOUNCEMENTS_URL)
 			.send()
 			.await?
-			.text()
+			.limit_read_text(1024 * 1024)
 			.await?;
 
 		let response = serde_json::from_str::<CheckForAnnouncementsResponse>(&response)?;

src/service/federation/execute.rs

@@ -2,8 +2,8 @@
 
 use bytes::Bytes;
 use conduwuit::{
-	Err, Error, Result, debug, debug::INFO_SPAN_LEVEL, debug_error, debug_warn, err,
-	error::inspect_debug_log, implement, trace,
+	Err, Error, Result, debug, debug::INFO_SPAN_LEVEL, debug_error, debug_warn, err, implement,
+	trace, utils::response::LimitReadExt,
 };
 use http::{HeaderValue, header::AUTHORIZATION};
 use ipaddress::IPAddress;
@@ -133,7 +133,22 @@ async fn handle_response<T>(
 where
 	T: OutgoingRequest + Send,
 {
-	let response = into_http_response(dest, actual, method, url, response).await?;
+	const HUGE_ENDPOINTS: [&str; 2] =
+		["/_matrix/federation/v2/send_join/", "/_matrix/federation/v2/state/"];
+	let size_limit: u64 = if HUGE_ENDPOINTS.iter().any(|e| url.path().starts_with(e)) {
+		// Some federation endpoints can return huge response bodies, so we'll bump the
+		// limit for those endpoints specifically.
+		self.services
+			.server
+			.config
+			.max_request_size
+			.saturating_mul(10)
+	} else {
+		self.services.server.config.max_request_size
+	}
+	.try_into()
+	.expect("size_limit (usize) should fit within a u64");
+	let response = into_http_response(dest, actual, method, url, response, size_limit).await?;
 
 	T::IncomingResponse::try_from_http_response(response)
 		.map_err(|e| err!(BadServerResponse("Server returned bad 200 response: {e:?}")))
@@ -145,6 +160,7 @@ async fn into_http_response(
 	method: &Method,
 	url: &Url,
 	mut response: Response,
+	max_size: u64,
 ) -> Result<http::Response<Bytes>> {
 	let status = response.status();
 	trace!(
@@ -167,14 +183,14 @@ async fn into_http_response(
 	);
 
 	trace!("Waiting for response body...");
-	let body = response
-		.bytes()
-		.await
-		.inspect_err(inspect_debug_log)
-		.unwrap_or_else(|_| Vec::new().into());
-
 	let http_response = http_response_builder
-		.body(body)
+		.body(
+			response
+				.limit_read(max_size)
+				.await
+				.unwrap_or_default()
+				.into(),
+		)
 		.expect("reqwest body is valid http body");
 
 	debug!("Got {status:?} for {method} {url}");

src/service/media/preview.rs

@@ -7,7 +7,7 @@
 
 use std::time::SystemTime;
 
-use conduwuit::{Err, Result, debug, err};
+use conduwuit::{Err, Result, debug, err, utils::response::LimitReadExt};
 use conduwuit_core::implement;
 use ipaddress::IPAddress;
 use serde::Serialize;
@@ -112,8 +112,22 @@ pub async fn download_image(&self, url: &str) -> Result<UrlPreviewData> {
 	use image::ImageReader;
 	use ruma::Mxc;
 
-	let image = self.services.client.url_preview.get(url).send().await?;
-	let image = image.bytes().await?;
+	let image = self
+		.services
+		.client
+		.url_preview
+		.get(url)
+		.send()
+		.await?
+		.limit_read(
+			self.services
+				.server
+				.config
+				.max_request_size
+				.try_into()
+				.expect("u64 should fit in usize"),
+		)
+		.await?;
 	let mxc = Mxc {
 		server_name: self.services.globals.server_name(),
 		media_id: &random_string(super::MXC_LENGTH),
@@ -151,24 +165,20 @@ async fn download_html(&self, url: &str) -> Result<UrlPreviewData> {
 	use webpage::HTML;
 
 	let client = &self.services.client.url_preview;
-	let mut response = client.get(url).send().await?;
-
-	let mut bytes: Vec<u8> = Vec::new();
-	while let Some(chunk) = response.chunk().await? {
-		bytes.extend_from_slice(&chunk);
-		if bytes.len() > self.services.globals.url_preview_max_spider_size() {
-			debug!(
-				"Response body from URL {} exceeds url_preview_max_spider_size ({}), not \
-				 processing the rest of the response body and assuming our necessary data is in \
-				 this range.",
-				url,
-				self.services.globals.url_preview_max_spider_size()
-			);
-			break;
-		}
-	}
-	let body = String::from_utf8_lossy(&bytes);
-	let Ok(html) = HTML::from_string(body.to_string(), Some(url.to_owned())) else {
+	let body = client
+		.get(url)
+		.send()
+		.await?
+		.limit_read_text(
+			self.services
+				.server
+				.config
+				.max_request_size
+				.try_into()
+				.expect("u64 should fit in usize"),
+		)
+		.await?;
+	let Ok(html) = HTML::from_string(body.clone(), Some(url.to_owned())) else {
 		return Err!(Request(Unknown("Failed to parse HTML")));
 	};
 

src/service/media/remote.rs

@@ -2,7 +2,7 @@
 
 use conduwuit::{
 	Err, Error, Result, debug_warn, err, implement,
-	utils::content_disposition::make_content_disposition,
+	utils::{content_disposition::make_content_disposition, response::LimitReadExt},
 };
 use http::header::{CONTENT_DISPOSITION, CONTENT_TYPE, HeaderValue};
 use ruma::{
@@ -286,10 +286,15 @@ async fn location_request(&self, location: &str) -> Result<FileMeta> {
 		.and_then(Result::ok);
 
 	response
-		.bytes()
+		.limit_read(
+			self.services
+				.server
+				.config
+				.max_request_size
+				.try_into()
+				.expect("u64 should fit in usize"),
+		)
 		.await
-		.map(Vec::from)
-		.map_err(Into::into)
 		.map(|content| FileMeta {
 			content: Some(content),
 			content_type: content_type.clone(),

src/service/pusher/mod.rs

@@ -1,6 +1,7 @@
 use std::{fmt::Debug, mem, sync::Arc};
 
 use bytes::BytesMut;
+use conduwuit::utils::response::LimitReadExt;
 use conduwuit_core::{
 	Err, Event, Result, debug_warn, err, trace,
 	utils::{stream::TryIgnore, string_from_bytes},
@@ -30,7 +31,7 @@
 	uint,
 };
 
-use crate::{Dep, client, globals, rooms, sending, users};
+use crate::{Dep, client, config, globals, rooms, sending, users};
 
 pub struct Service {
 	db: Data,
@@ -39,6 +40,7 @@ pub struct Service {
 
 struct Services {
 	globals: Dep<globals::Service>,
+	config: Dep<config::Service>,
 	client: Dep<client::Service>,
 	state_accessor: Dep<rooms::state_accessor::Service>,
 	state_cache: Dep<rooms::state_cache::Service>,
@@ -61,6 +63,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 			services: Services {
 				globals: args.depend::<globals::Service>("globals"),
 				client: args.depend::<client::Service>("client"),
+				config: args.depend::<config::Service>("config"),
 				state_accessor: args
 					.depend::<rooms::state_accessor::Service>("rooms::state_accessor"),
 				state_cache: args.depend::<rooms::state_cache::Service>("rooms::state_cache"),
@@ -245,7 +248,15 @@ pub async fn send_request<T>(&self, dest: &str, request: T) -> Result<T::Incomin
 						.expect("http::response::Builder is usable"),
 				);
 
-				let body = response.bytes().await?;
+				let body = response
+					.limit_read(
+						self.services
+							.config
+							.max_request_size
+							.try_into()
+							.expect("usize fits into u64"),
+					)
+					.await?;
 
 				if !status.is_success() {
 					debug_warn!("Push gateway response body: {:?}", string_from_bytes(&body));

src/service/resolver/well_known.rs

@@ -1,4 +1,6 @@
-use conduwuit::{Result, debug, debug_error, debug_info, debug_warn, implement, trace};
+use conduwuit::{
+	Result, debug, debug_error, debug_info, implement, trace, utils::response::LimitReadExt,
+};
 
 #[implement(super::Service)]
 #[tracing::instrument(name = "well-known", level = "debug", skip(self, dest))]
@@ -24,12 +26,8 @@ pub(super) async fn request_well_known(&self, dest: &str) -> Result<Option<Strin
 		return Ok(None);
 	}
 
-	let text = response.text().await?;
+	let text = response.limit_read_text(8192).await?;
 	trace!("response text: {text:?}");
-	if text.len() >= 12288 {
-		debug_warn!("response contains junk");
-		return Ok(None);
-	}
 
 	let body: serde_json::Value = serde_json::from_str(&text).unwrap_or_default();
 

src/service/rooms/timeline/append.rs

@@ -72,6 +72,26 @@ pub async fn append_incoming_pdu<'a, Leaves>(
 		.append_pdu(pdu, pdu_json, new_room_leaves, state_lock, room_id)
 		.await?;
 
+	// Process admin commands for federation events
+	if *pdu.kind() == TimelineEventType::RoomMessage {
+		let content: ExtractBody = pdu.get_content()?;
+		if let Some(body) = content.body {
+			if let Some(source) = self
+				.services
+				.admin
+				.is_admin_command(pdu, &body, false)
+				.await
+			{
+				self.services.admin.command_with_sender(
+					body,
+					Some(pdu.event_id().into()),
+					source,
+					pdu.sender.clone().into(),
+				)?;
+			}
+		}
+	}
+
 	Ok(Some(pdu_id))
 }
 
@@ -334,15 +354,6 @@ pub async fn append_pdu<'a, Leaves>(
 			let content: ExtractBody = pdu.get_content()?;
 			if let Some(body) = content.body {
 				self.services.search.index_pdu(shortroomid, &pdu_id, &body);
-
-				if let Some(source) = self.services.admin.is_admin_command(pdu, &body).await {
-					self.services.admin.command_with_sender(
-						body,
-						Some((pdu.event_id()).into()),
-						source,
-						pdu.sender.clone().into(),
-					)?;
-				}
 			}
 		},
 		| _ => {},

src/service/rooms/timeline/build.rs

@@ -18,7 +18,7 @@
 	},
 };
 
-use super::RoomMutexGuard;
+use super::{ExtractBody, RoomMutexGuard};
 
 /// Creates a new persisted data unit and adds it to a room. This function
 /// takes a roomid_mutex_state, meaning that only this function is able to
@@ -126,6 +126,26 @@ pub async fn build_and_append_pdu(
 		.boxed()
 		.await?;
 
+	// Process admin commands for locally sent events
+	if *pdu.kind() == TimelineEventType::RoomMessage {
+		let content: ExtractBody = pdu.get_content()?;
+		if let Some(body) = content.body {
+			if let Some(source) = self
+				.services
+				.admin
+				.is_admin_command(&pdu, &body, true)
+				.await
+			{
+				self.services.admin.command_with_sender(
+					body,
+					Some(pdu.event_id().into()),
+					source,
+					pdu.sender.clone().into(),
+				)?;
+			}
+		}
+	}
+
 	// We set the room state after inserting the pdu, so that we never have a moment
 	// in time where events in the current room state do not exist
 	trace!("Setting room state for room {room_id}");
@@ -167,6 +187,8 @@ pub async fn build_and_append_pdu(
 	Ok(pdu.event_id().to_owned())
 }
 
+/// Assert invariants about the admin room, to prevent (for example) all admins
+/// from leaving or being banned from the room
 #[implement(super::Service)]
 #[tracing::instrument(skip_all, level = "debug")]
 async fn check_pdu_for_admin_room<Pdu>(&self, pdu: &Pdu, sender: &UserId) -> Result

src/service/sending/antispam.rs

@@ -1,7 +1,7 @@
 use std::{fmt::Debug, mem};
 
 use bytes::BytesMut;
-use conduwuit::{Err, Result, debug_error, err, utils, warn};
+use conduwuit::{Err, Result, debug_error, err, utils, utils::response::LimitReadExt, warn};
 use reqwest::Client;
 use ruma::api::{IncomingResponse, MatrixVersion, OutgoingRequest, SendAccessToken};
 
@@ -38,7 +38,7 @@ pub(crate) async fn send_antispam_request<T>(
 			.expect("http::response::Builder is usable"),
 	);
 
-	let body = response.bytes().await?; // TODO: handle timeout
+	let body = response.limit_read(65535).await?; // TODO: handle timeout
 
 	if !status.is_success() {
 		debug_error!("Antispam response bytes: {:?}", utils::string_from_bytes(&body));

src/service/sending/appservice.rs

@@ -1,7 +1,9 @@
 use std::{fmt::Debug, mem};
 
 use bytes::BytesMut;
-use conduwuit::{Err, Result, debug_error, err, implement, trace, utils, warn};
+use conduwuit::{
+	Err, Result, debug_error, err, implement, trace, utils, utils::response::LimitReadExt, warn,
+};
 use ruma::api::{
 	IncomingResponse, MatrixVersion, OutgoingRequest, SendAccessToken, appservice::Registration,
 };
@@ -77,7 +79,15 @@ pub async fn send_appservice_request<T>(
 			.expect("http::response::Builder is usable"),
 	);
 
-	let body = response.bytes().await?;
+	let body = response
+		.limit_read(
+			self.server
+				.config
+				.max_request_size
+				.try_into()
+				.expect("usize fits into u64"),
+		)
+		.await?;
 
 	if !status.is_success() {
 		debug_error!("Appservice response bytes: {:?}", utils::string_from_bytes(&body));

src/service/sending/sender.rs

@@ -10,7 +10,7 @@
 
 use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD};
 use conduwuit_core::{
-	Error, Event, Result, debug, err, error,
+	Error, Event, Result, at, debug, err, error,
 	result::LogErr,
 	trace,
 	utils::{
@@ -175,7 +175,7 @@ async fn handle_response_ok<'a>(
 		if !new_events.is_empty() {
 			self.db.mark_as_active(new_events.iter());
 
-			let new_events_vec = new_events.into_iter().map(|(_, event)| event).collect();
+			let new_events_vec = new_events.into_iter().map(at!(1)).collect();
 			futures.push(self.send_events(dest.clone(), new_events_vec));
 		} else {
 			statuses.remove(dest);

src/service/users/dehydrated_device.rs

@@ -0,0 +1,149 @@
+use conduwuit::{Err, Result, implement, trace};
+use conduwuit_database::{Deserialized, Json};
+use ruma::{
+	DeviceId, OwnedDeviceId, UserId,
+	api::client::dehydrated_device::{
+		DehydratedDeviceData, put_dehydrated_device::unstable::Request,
+	},
+	serde::Raw,
+};
+use serde::{Deserialize, Serialize};
+
+#[derive(Clone, Debug, Serialize, Deserialize)]
+pub struct DehydratedDevice {
+	/// Unique ID of the device.
+	pub device_id: OwnedDeviceId,
+
+	/// Contains serialized and encrypted private data.
+	pub device_data: Raw<DehydratedDeviceData>,
+}
+
+/// Creates or recreates the user's dehydrated device.
+#[implement(super::Service)]
+#[tracing::instrument(
+	level = "info",
+	skip_all,
+	fields(
+		%user_id,
+		device_id = %request.device_id,
+		display_name = ?request.initial_device_display_name,
+	)
+)]
+pub async fn set_dehydrated_device(&self, user_id: &UserId, request: Request) -> Result {
+	assert!(
+		self.exists(user_id).await,
+		"Tried to create dehydrated device for non-existent user"
+	);
+
+	let existing_id = self.get_dehydrated_device_id(user_id).await;
+
+	if existing_id.is_err()
+		&& self
+			.get_device_metadata(user_id, &request.device_id)
+			.await
+			.is_ok()
+	{
+		return Err!("A hydrated device already exists with that ID.");
+	}
+
+	if let Ok(existing_id) = existing_id {
+		self.remove_device(user_id, &existing_id).await;
+	}
+
+	self.create_device(
+		user_id,
+		&request.device_id,
+		"",
+		request.initial_device_display_name.clone(),
+		None,
+	)
+	.await?;
+
+	trace!(device_data = ?request.device_data);
+	self.db.userid_dehydrateddevice.raw_put(
+		user_id,
+		Json(&DehydratedDevice {
+			device_id: request.device_id.clone(),
+			device_data: request.device_data,
+		}),
+	);
+
+	trace!(device_keys = ?request.device_keys);
+	self.add_device_keys(user_id, &request.device_id, &request.device_keys)
+		.await;
+
+	trace!(one_time_keys = ?request.one_time_keys);
+	for (one_time_key_key, one_time_key_value) in &request.one_time_keys {
+		self.add_one_time_key(user_id, &request.device_id, one_time_key_key, one_time_key_value)
+			.await?;
+	}
+
+	Ok(())
+}
+
+/// Removes a user's dehydrated device.
+///
+/// Calling this directly will remove the dehydrated data but leak the frontage
+/// device. Thus this is called by the regular device interface such that the
+/// dehydrated data will not leak instead.
+///
+/// If device_id is given, the user's dehydrated device must match or this is a
+/// no-op, but an Err is still returned to indicate that. Otherwise returns the
+/// removed dehydrated device_id.
+#[implement(super::Service)]
+#[tracing::instrument(
+	level = "debug",
+	skip_all,
+	fields(
+		%user_id,
+		device_id = ?maybe_device_id,
+	)
+)]
+pub(super) async fn remove_dehydrated_device(
+	&self,
+	user_id: &UserId,
+	maybe_device_id: Option<&DeviceId>,
+) -> Result<OwnedDeviceId> {
+	let Ok(device_id) = self.get_dehydrated_device_id(user_id).await else {
+		return Err!(Request(NotFound("No dehydrated device for this user.")));
+	};
+
+	if let Some(maybe_device_id) = maybe_device_id {
+		if maybe_device_id != device_id {
+			return Err!(Request(NotFound("Not the user's dehydrated device.")));
+		}
+	}
+
+	self.db.userid_dehydrateddevice.remove(user_id);
+
+	Ok(device_id)
+}
+
+/// Get the device_id of the user's dehydrated device.
+#[implement(super::Service)]
+#[tracing::instrument(
+	level = "debug",
+	skip_all,
+	fields(%user_id)
+)]
+pub async fn get_dehydrated_device_id(&self, user_id: &UserId) -> Result<OwnedDeviceId> {
+	self.get_dehydrated_device(user_id)
+		.await
+		.map(|device| device.device_id)
+}
+
+/// Get the dehydrated device private data
+#[implement(super::Service)]
+#[tracing::instrument(
+	level = "debug",
+	skip_all,
+	fields(%user_id),
+	ret,
+)]
+pub async fn get_dehydrated_device(&self, user_id: &UserId) -> Result<DehydratedDevice> {
+	self.db
+		.userid_dehydrateddevice
+		.get(user_id)
+		.await
+		.deserialized()
+}

src/service/users/mod.rs

@@ -1,3 +1,5 @@
+pub(super) mod dehydrated_device;
+
 #[cfg(feature = "ldap")]
 use std::collections::HashMap;
 use std::{collections::BTreeMap, mem, net::IpAddr, sync::Arc};
@@ -5,7 +7,7 @@
 #[cfg(feature = "ldap")]
 use conduwuit::result::LogErr;
 use conduwuit::{
-	Err, Error, Result, Server, at, debug_warn, err, is_equal_to, trace,
+	Err, Error, Result, Server, debug_warn, err, is_equal_to, trace,
 	utils::{self, ReadyExt, stream::TryIgnore, string::Unquoted},
 };
 #[cfg(feature = "ldap")]
@@ -70,6 +72,7 @@ struct Data {
 	userfilterid_filter: Arc<Map>,
 	userid_avatarurl: Arc<Map>,
 	userid_blurhash: Arc<Map>,
+	userid_dehydrateddevice: Arc<Map>,
 	userid_devicelistversion: Arc<Map>,
 	userid_displayname: Arc<Map>,
 	userid_lastonetimekeyupdate: Arc<Map>,
@@ -110,6 +113,7 @@ fn build(args: crate::Args<'_>) -> Result<Arc<Self>> {
 				userfilterid_filter: args.db["userfilterid_filter"].clone(),
 				userid_avatarurl: args.db["userid_avatarurl"].clone(),
 				userid_blurhash: args.db["userid_blurhash"].clone(),
+				userid_dehydrateddevice: args.db["userid_dehydrateddevice"].clone(),
 				userid_devicelistversion: args.db["userid_devicelistversion"].clone(),
 				userid_displayname: args.db["userid_displayname"].clone(),
 				userid_lastonetimekeyupdate: args.db["userid_lastonetimekeyupdate"].clone(),
@@ -480,6 +484,11 @@ pub async fn create_device(
 
 	/// Removes a device from a user.
 	pub async fn remove_device(&self, user_id: &UserId, device_id: &DeviceId) {
+		// Remove dehydrated device if this is the dehydrated device
+		let _: Result<_> = self
+			.remove_dehydrated_device(user_id, Some(device_id))
+			.await;
+
 		let userdeviceid = (user_id, device_id);
 
 		// Remove tokens
@@ -1003,7 +1012,7 @@ pub fn get_to_device_events<'a>(
 		device_id: &'a DeviceId,
 		since: Option<u64>,
 		to: Option<u64>,
-	) -> impl Stream<Item = Raw<AnyToDeviceEvent>> + Send + 'a {
+	) -> impl Stream<Item = (u64, Raw<AnyToDeviceEvent>)> + Send + 'a {
 		type Key<'a> = (&'a UserId, &'a DeviceId, u64);
 
 		let from = (user_id, device_id, since.map_or(0, |since| since.saturating_add(1)));
@@ -1017,7 +1026,7 @@ pub fn get_to_device_events<'a>(
 					&& device_id == *device_id_
 					&& to.is_none_or(|to| *count <= to)
 			})
-			.map(at!(1))
+			.map(|((_, _, count), event)| (count, event))
 	}
 
 	pub async fn remove_to_device_events<Until>(