WIP: upstream OIDC provider support

crates/handlers/src/upstream_oauth2/authorize.rs

@@ -0,0 +1,149 @@
+// Copyright 2022 The Matrix.org Foundation C.I.C.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use axum::{
+    extract::{Path, State},
+    response::{IntoResponse, Redirect},
+};
+use axum_extra::extract::{cookie::Cookie, PrivateCookieJar};
+use hyper::StatusCode;
+use mas_http::ClientInitError;
+use mas_keystore::Encrypter;
+use mas_oidc_client::{
+    error::{AuthorizationError, DiscoveryError},
+    requests::authorization_code::AuthorizationRequestData,
+};
+use mas_router::UrlBuilder;
+use mas_storage::{upstream_oauth2::lookup_provider, LookupResultExt};
+use sqlx::PgPool;
+use thiserror::Error;
+use ulid::Ulid;
+
+use super::http_service;
+
+#[derive(Debug, Error)]
+pub(crate) enum RouteError {
+    #[error("Provider not found")]
+    ProviderNotFound,
+
+    #[error(transparent)]
+    Authorization(#[from] AuthorizationError),
+
+    #[error(transparent)]
+    InternalError(Box<dyn std::error::Error>),
+
+    #[error(transparent)]
+    Anyhow(#[from] anyhow::Error),
+}
+
+impl From<sqlx::Error> for RouteError {
+    fn from(e: sqlx::Error) -> Self {
+        Self::InternalError(Box::new(e))
+    }
+}
+
+impl From<DiscoveryError> for RouteError {
+    fn from(e: DiscoveryError) -> Self {
+        Self::InternalError(Box::new(e))
+    }
+}
+
+impl From<mas_storage::upstream_oauth2::ProviderLookupError> for RouteError {
+    fn from(e: mas_storage::upstream_oauth2::ProviderLookupError) -> Self {
+        Self::InternalError(Box::new(e))
+    }
+}
+
+impl From<ClientInitError> for RouteError {
+    fn from(e: ClientInitError) -> Self {
+        Self::InternalError(Box::new(e))
+    }
+}
+
+impl IntoResponse for RouteError {
+    fn into_response(self) -> axum::response::Response {
+        match self {
+            Self::ProviderNotFound => (StatusCode::NOT_FOUND, "Provider not found").into_response(),
+            Self::Authorization(e) => {
+                (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response()
+            }
+            Self::InternalError(e) => {
+                (StatusCode::INTERNAL_SERVER_ERROR, e.to_string()).into_response()
+            }
+            Self::Anyhow(e) => {
+                (StatusCode::INTERNAL_SERVER_ERROR, format!("{e:?}")).into_response()
+            }
+        }
+    }
+}
+
+pub(crate) async fn get(
+    State(pool): State<PgPool>,
+    State(url_builder): State<UrlBuilder>,
+    cookie_jar: PrivateCookieJar<Encrypter>,
+    Path(provider_id): Path<Ulid>,
+) -> Result<impl IntoResponse, RouteError> {
+    let (clock, mut rng) = crate::rng_and_clock()?;
+
+    let mut txn = pool.begin().await?;
+
+    let provider = lookup_provider(&mut txn, provider_id)
+        .await
+        .to_option()?
+        .ok_or(RouteError::ProviderNotFound)?;
+
+    let http_service = http_service("upstream-discover").await?;
+
+    // First, discover the provider
+    let metadata =
+        mas_oidc_client::requests::discovery::discover(&http_service, &provider.issuer).await?;
+
+    let redirect_uri = url_builder.upstream_oauth_callback(provider.id);
+
+    let data = AuthorizationRequestData {
+        client_id: &provider.client_id,
+        scope: &provider.scope,
+        prompt: None,
+        redirect_uri: &redirect_uri,
+        code_challenge_methods_supported: metadata.code_challenge_methods_supported.as_deref(),
+    };
+
+    // Build an authorization request for it
+    let (url, data) = mas_oidc_client::requests::authorization_code::build_authorization_url(
+        metadata.authorization_endpoint().clone(),
+        data,
+        &mut rng,
+    )?;
+
+    let session = mas_storage::upstream_oauth2::add_session(
+        &mut txn,
+        &mut rng,
+        &clock,
+        &provider,
+        data.state,
+        data.code_challenge_verifier,
+        data.nonce,
+    )
+    .await?;
+
+    // TODO: handle that cookie somewhere else?
+    let mut cookie = Cookie::new("upstream-oauth2-session-id", session.id.to_string());
+    cookie.set_path("/");
+    cookie.set_http_only(true);
+    let cookie_jar = cookie_jar.add(cookie);
+
+    txn.commit().await?;
+
+    Ok((cookie_jar, Redirect::temporary(url.as_str())))
+}