Expose end_session endpoint to perform rp_initiated_logout

crates/handlers/src/lib.rs

@@ -429,6 +429,10 @@ where
             mas_router::OAuth2AuthorizationEndpoint::route(),
             get(self::oauth2::authorization::get),
         )
+        .route(
+            mas_router::OAuth2EndSession::route(),
+            get(self::oauth2::end_session::get),
+        )
         .route(
             mas_router::Consent::route(),
             get(self::oauth2::authorization::consent::get)

crates/handlers/src/oauth2/discovery.rs

@@ -65,6 +65,7 @@ pub(crate) async fn get(
     let revocation_endpoint = Some(url_builder.oauth_revocation_endpoint());
     let userinfo_endpoint = Some(url_builder.oidc_userinfo_endpoint());
     let registration_endpoint = Some(url_builder.oauth_registration_endpoint());
+    let end_session_endpoint = Some(url_builder.oauth_end_session_endpoint());
 
     let scopes_supported = Some(vec![scope::OPENID.to_string(), scope::EMAIL.to_string()]);
 
@@ -172,6 +173,7 @@ pub(crate) async fn get(
         request_uri_parameter_supported,
         prompt_values_supported,
         device_authorization_endpoint,
+        end_session_endpoint,
         ..ProviderMetadata::default()
     };
 

crates/handlers/src/oauth2/end_session.rs

@@ -0,0 +1,211 @@
+// Copyright 2024, 2025 New Vector Ltd.
+// Copyright 2023, 2024 The Matrix.org Foundation C.I.C.
+//
+// SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+// Please see LICENSE files in the repository root for full details.
+use axum::{
+    Json,
+    extract::State,
+    response::{IntoResponse, Redirect, Response},
+};
+use axum_extra::extract::Query;
+use hyper::StatusCode;
+use mas_axum_utils::{SessionInfoExt, cookies::CookieJar, record_error};
+use mas_data_model::{BoxClock, BoxRng, Clock};
+use mas_keystore::Keystore;
+use mas_oidc_client::{
+    error::IdTokenError,
+    requests::jose::{JwtVerificationData, verify_id_token},
+};
+use mas_router::UrlBuilder;
+use mas_storage::{
+    BoxRepository, RepositoryAccess,
+    queue::{QueueJobRepositoryExt as _, SyncDevicesJob},
+    user::BrowserSessionRepository,
+};
+use oauth2_types::errors::{ClientError, ClientErrorCode};
+use serde::{Deserialize, Serialize};
+use thiserror::Error;
+
+use crate::{BoundActivityTracker, impl_from_error_for_route};
+
+#[derive(Debug, Deserialize, Serialize)]
+pub(crate) struct EndSessionParam {
+    id_token_hint: String,
+    post_logout_redirect_uri: String,
+}
+
+#[derive(Debug, Error)]
+pub(crate) enum RouteError {
+    #[error(transparent)]
+    Internal(Box<dyn std::error::Error + Send + Sync + 'static>),
+
+    #[error("bad request")]
+    BadRequest,
+
+    #[error("client not found")]
+    ClientNotFound,
+
+    #[error("client is unauthorized")]
+    UnauthorizedClient,
+
+    // #[error("unsupported token type")]
+    // UnsupportedTokenType,
+    #[error("unknown token")]
+    UnknownToken,
+}
+
+impl_from_error_for_route!(mas_storage::RepositoryError);
+
+impl IntoResponse for RouteError {
+    fn into_response(self) -> Response {
+        let sentry_event_id = record_error!(self, Self::Internal(_));
+        let response = match self {
+            Self::Internal(_) => (
+                StatusCode::INTERNAL_SERVER_ERROR,
+                Json(ClientError::from(ClientErrorCode::ServerError)),
+            )
+                .into_response(),
+
+            Self::BadRequest => (
+                StatusCode::BAD_REQUEST,
+                Json(ClientError::from(ClientErrorCode::InvalidRequest)),
+            )
+                .into_response(),
+
+            Self::ClientNotFound => (
+                StatusCode::UNAUTHORIZED,
+                Json(ClientError::from(ClientErrorCode::InvalidClient)),
+            )
+                .into_response(),
+
+            // Self::ClientNotAllowed |
+            Self::UnauthorizedClient => (
+                StatusCode::UNAUTHORIZED,
+                Json(ClientError::from(ClientErrorCode::UnauthorizedClient)),
+            )
+                .into_response(),
+
+            // Self::UnsupportedTokenType => (
+            //     StatusCode::BAD_REQUEST,
+            //     Json(ClientError::from(ClientErrorCode::UnsupportedTokenType)),
+            // )
+            //     .into_response(),
+
+            // If the token is unknown, we still return a 200 OK response.
+            Self::UnknownToken => StatusCode::OK.into_response(),
+        };
+
+        (sentry_event_id, response).into_response()
+    }
+}
+
+impl From<IdTokenError> for RouteError {
+    fn from(_e: IdTokenError) -> Self {
+        Self::UnknownToken
+    }
+}
+
+#[tracing::instrument(name = "handlers.oauth2.end_session.get", skip_all)]
+pub(crate) async fn get(
+    mut rng: BoxRng,
+    clock: BoxClock,
+    State(key_store): State<Keystore>,
+    State(url_builder): State<UrlBuilder>,
+    mut repo: BoxRepository,
+    activity_tracker: BoundActivityTracker,
+    Query(params): Query<EndSessionParam>,
+    cookie_jar: CookieJar,
+) -> Result<Response, RouteError> {
+    let (session_info, cookie_jar) = cookie_jar.session_info();
+
+    let browser_session_id = session_info
+        .current_session_id()
+        .ok_or(RouteError::BadRequest)?;
+
+    let browser_session = repo
+        .browser_session()
+        .lookup(browser_session_id)
+        .await?
+        .ok_or(RouteError::BadRequest)?;
+
+    let oauth_session = repo
+        .oauth2_session()
+        .find_by_browser_session(browser_session.id)
+        .await?
+        .ok_or(RouteError::BadRequest)?;
+
+    let client = repo
+        .oauth2_client()
+        .lookup(oauth_session.client_id)
+        .await?
+        .filter(|client| client.id_token_signed_response_alg.is_some())
+        .ok_or(RouteError::ClientNotFound)?;
+
+    let jwks = key_store.public_jwks();
+    let issuer: String = url_builder.oidc_issuer().into();
+
+    let id_token_verification_data = JwtVerificationData {
+        issuer: Some(&issuer),
+        jwks: &jwks,
+        signing_algorithm: &client.id_token_signed_response_alg.unwrap(),
+        client_id: &client.client_id,
+    };
+
+    verify_id_token(
+        &params.id_token_hint,
+        id_token_verification_data,
+        None,
+        clock.now(),
+    )?;
+
+    // Check that the session is still valid.
+    if !oauth_session.is_valid() {
+        // If the session is not valid, we redirect to post logout uri
+        return Ok((cookie_jar, Redirect::to(&params.post_logout_redirect_uri)).into_response());
+    }
+
+    // Check that the client ending the session is the same as the client that
+    // created it.
+    if client.id != oauth_session.client_id {
+        return Err(RouteError::UnauthorizedClient);
+    }
+
+    activity_tracker
+        .record_oauth2_session(&clock, &oauth_session)
+        .await;
+
+    // If the session is associated with a user, make sure we schedule a device
+    // deletion job for all the devices associated with the session.
+    if let Some(user_id) = oauth_session.user_id {
+        // Fetch the user
+        let user = repo
+            .user()
+            .lookup(user_id)
+            .await?
+            .ok_or(RouteError::UnknownToken)?;
+
+        // Schedule a job to sync the devices of the user with the homeserver
+        repo.queue_job()
+            .schedule_job(&mut rng, &clock, SyncDevicesJob::new(&user))
+            .await?;
+    }
+
+    // Now that we checked everything, we can end the session.
+    repo.oauth2_session().finish(&clock, oauth_session).await?;
+
+    activity_tracker
+        .record_browser_session(&clock, &browser_session)
+        .await;
+    repo.browser_session()
+        .finish(&clock, browser_session)
+        .await?;
+
+    repo.save().await?;
+
+    // We always want to clear out the session cookie, even if the session was
+    // invalid
+    let cookie_jar = cookie_jar.update_session_info(&session_info.mark_session_ended());
+
+    Ok((cookie_jar, Redirect::to(&params.post_logout_redirect_uri)).into_response())
+}

crates/handlers/src/oauth2/mod.rs

@@ -25,6 +25,7 @@ use thiserror::Error;
 pub mod authorization;
 pub mod device;
 pub mod discovery;
+pub mod end_session;
 pub mod introspection;
 pub mod keys;
 pub mod registration;

crates/router/src/endpoints.rs

@@ -155,6 +155,14 @@ impl SimpleRoute for OAuth2AuthorizationEndpoint {
     const PATH: &'static str = "/authorize";
 }
 
+/// `POST /oauth2/end_session`
+#[derive(Default, Debug, Clone)]
+pub struct OAuth2EndSession;
+
+impl SimpleRoute for OAuth2EndSession {
+    const PATH: &'static str = "/oauth2/end_session";
+}
+
 /// `GET /`
 #[derive(Default, Debug, Clone)]
 pub struct Index;

crates/router/src/url_builder.rs

@@ -160,6 +160,12 @@ impl UrlBuilder {
         self.absolute_url_for(&crate::endpoints::OAuth2Revocation)
     }
 
+    /// OAuth 2.0 revocation endpoint
+    #[must_use]
+    pub fn oauth_end_session_endpoint(&self) -> Url {
+        self.absolute_url_for(&crate::endpoints::OAuth2EndSession)
+    }
+
     /// OAuth 2.0 client registration endpoint
     #[must_use]
     pub fn oauth_registration_endpoint(&self) -> Url {