Fix alias resolution logic; element-web v1.11.111 compat

element-hq/element-web#30641
element-hq/element-web#30611

Signed-off-by: Jason Volk <jason@zemos.net>

src/api/client/directory.rs

@@ -403,18 +403,18 @@ async fn public_rooms_chunk(services: &Services, room_id: OwnedRoomId) -> Public
 	let canonical_alias = services
 		.state_accessor
 		.get_canonical_alias(&room_id)
-		.and_then(async |alias| {
-			if services
-				.globals
-				.server_is_ours(alias.server_name())
-				&& !services.alias.local_alias_exists(&alias).await
+		.ok()
+		.then(async |alias| {
+			if let Some(alias) = alias
+				&& services.globals.alias_is_local(&alias)
+				&& let Ok(alias_room_id) = services.alias.resolve_local_alias(&alias).await
+				&& alias_room_id == room_id
 			{
-				return Err!(Request(NotFound("Canonical alias not found.")));
+				Some(alias)
+			} else {
+				None
 			}
-
-			Ok(alias)
-		})
-		.ok();
+		});
 
 	let avatar_url = services
 		.state_accessor

src/service/globals/mod.rs

@@ -11,7 +11,9 @@ use std::{
 use async_trait::async_trait;
 use data::Data;
 use regex::RegexSet;
-use ruma::{OwnedEventId, OwnedRoomAliasId, OwnedServerName, OwnedUserId, ServerName, UserId};
+use ruma::{
+	OwnedEventId, OwnedRoomAliasId, OwnedServerName, OwnedUserId, RoomAliasId, ServerName, UserId,
+};
 use tuwunel_core::{Result, Server, error, utils::bytes::pretty};
 
 use crate::service;
@@ -250,6 +252,12 @@ impl Service {
 		self.server_is_ours(user_id.server_name())
 	}
 
+	#[inline]
+	#[must_use]
+	pub fn alias_is_local(&self, alias: &RoomAliasId) -> bool {
+		self.server_is_ours(alias.server_name())
+	}
+
 	#[inline]
 	#[must_use]
 	pub fn server_is_ours(&self, server_name: &ServerName) -> bool {

src/service/rooms/alias/mod.rs

@@ -125,33 +125,30 @@ impl Service {
 		room_alias: &RoomAliasId,
 		servers: Option<Vec<OwnedServerName>>,
 	) -> Result<(OwnedRoomId, Vec<OwnedServerName>)> {
-		let server_name = room_alias.server_name();
-		let server_is_ours = self.services.globals.server_is_ours(server_name);
-		let servers_contains_ours = || {
-			servers
-				.as_ref()
-				.is_some_and(|servers| servers.contains(&self.services.server.name))
-		};
+		if self
+			.services
+			.globals
+			.server_is_ours(room_alias.server_name())
+		{
+			if let Ok(room_id) = self.resolve_local_alias(room_alias).await {
+				return Ok((room_id, Vec::new()));
+			}
 
-		if !server_is_ours && !servers_contains_ours() {
-			return self
-				.remote_resolve(room_alias, servers.unwrap_or_default())
-				.await;
+			if let Ok(room_id) = self.resolve_appservice_alias(room_alias).await {
+				return Ok((room_id, Vec::new()));
+			}
+
+			return Err!(Request(NotFound("Room with alias not found.")));
 		}
 
-		let room_id = match self.resolve_local_alias(room_alias).await {
-			| Ok(r) => Some(r),
-			| Err(_) => self.resolve_appservice_alias(room_alias).await?,
-		};
-
-		room_id.map_or_else(
-			|| Err!(Request(NotFound("Room with alias not found."))),
-			|room_id| Ok((room_id, Vec::new())),
-		)
+		return self
+			.remote_resolve(room_alias, servers.unwrap_or_default())
+			.await;
 	}
 
 	#[tracing::instrument(skip(self), level = "trace")]
 	pub async fn resolve_local_alias(&self, alias: &RoomAliasId) -> Result<OwnedRoomId> {
+		self.check_alias_local(alias)?;
 		self.db
 			.alias_roomid
 			.get(alias.alias())
@@ -159,15 +156,6 @@ impl Service {
 			.deserialized()
 	}
 
-	#[tracing::instrument(skip(self), level = "trace")]
-	pub async fn local_alias_exists(&self, alias: &RoomAliasId) -> bool {
-		self.db
-			.alias_roomid
-			.exists(alias.alias())
-			.await
-			.is_ok()
-	}
-
 	#[tracing::instrument(skip(self), level = "debug")]
 	pub fn local_aliases_for_room<'a>(
 		&'a self,
@@ -191,6 +179,8 @@ impl Service {
 	}
 
 	async fn user_can_remove_alias(&self, alias: &RoomAliasId, user_id: &UserId) -> Result<bool> {
+		self.check_alias_local(alias)?;
+
 		let room_id = self
 			.resolve_local_alias(alias)
 			.await
@@ -237,6 +227,8 @@ impl Service {
 	}
 
 	async fn who_created_alias(&self, alias: &RoomAliasId) -> Result<OwnedUserId> {
+		self.check_alias_local(alias)?;
+
 		self.db
 			.alias_userid
 			.get(alias.alias())
@@ -244,12 +236,11 @@ impl Service {
 			.deserialized()
 	}
 
-	async fn resolve_appservice_alias(
-		&self,
-		room_alias: &RoomAliasId,
-	) -> Result<Option<OwnedRoomId>> {
+	async fn resolve_appservice_alias(&self, room_alias: &RoomAliasId) -> Result<OwnedRoomId> {
 		use ruma::api::appservice::query::query_room_alias;
 
+		self.check_alias_local(room_alias)?;
+
 		for appservice in self.services.appservice.read().await.values() {
 			if appservice.aliases.is_match(room_alias.as_str())
 				&& matches!(
@@ -265,12 +256,19 @@ impl Service {
 				return self
 					.resolve_local_alias(room_alias)
 					.await
-					.map_err(|_| err!(Request(NotFound("Room does not exist."))))
-					.map(Some);
+					.map_err(|_| err!(Request(NotFound("Room does not exist."))));
 			}
 		}
 
-		Ok(None)
+		Err!(Request(NotFound("Room does not exist.")))
+	}
+
+	fn check_alias_local(&self, alias: &RoomAliasId) -> Result {
+		if !self.services.globals.alias_is_local(alias) {
+			return Err!(Request(InvalidParam("Alias is from another server.")));
+		}
+
+		Ok(())
 	}
 
 	#[tracing::instrument(skip(self, appservice_info), level = "trace")]
@@ -279,14 +277,7 @@ impl Service {
 		room_alias: &RoomAliasId,
 		appservice_info: &Option<RegistrationInfo>,
 	) -> Result {
-		if !self
-			.services
-			.globals
-			.server_is_ours(room_alias.server_name())
-		{
-			return Err!(Request(InvalidParam("Alias is from another server.")));
-		}
-
+		self.check_alias_local(room_alias)?;
 		if let Some(info) = appservice_info {
 			if !info.aliases.is_match(room_alias.as_str()) {
 				return Err!(Request(Exclusive("Room alias is not in namespace.")));