Implement SSO/OIDC support. (closes #7)

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

src/api/client/session/mod.rs

@@ -4,6 +4,7 @@ mod ldap;
 mod logout;
 mod password;
 mod refresh;
+mod sso;
 mod token;
 
 use axum::extract::State;
@@ -12,8 +13,8 @@ use ruma::api::client::session::{
 	get_login_types::{
 		self,
 		v3::{
-			ApplicationServiceLoginType, JwtLoginType, LoginType, PasswordLoginType,
-			TokenLoginType,
+			ApplicationServiceLoginType, IdentityProvider, JwtLoginType, LoginType,
+			PasswordLoginType, SsoLoginType, TokenLoginType,
 		},
 	},
 	login::{
@@ -28,6 +29,7 @@ use self::{ldap::ldap_login, password::password_login};
 pub(crate) use self::{
 	logout::{logout_all_route, logout_route},
 	refresh::refresh_token_route,
+	sso::{sso_callback_route, sso_login_route, sso_login_with_provider_route},
 	token::login_token_route,
 };
 use super::TOKEN_LENGTH;
@@ -50,6 +52,20 @@ pub(crate) async fn get_login_types_route(
 		LoginType::Token(TokenLoginType {
 			get_login_token: services.config.login_via_existing_session,
 		}),
+		LoginType::Sso(SsoLoginType {
+			identity_providers: services
+				.config
+				.identity_provider
+				.iter()
+				.cloned()
+				.map(|config| IdentityProvider {
+					id: config.id().to_owned(),
+					brand: Some(config.brand.clone().into()),
+					icon: config.icon,
+					name: config.name.unwrap_or(config.brand),
+				})
+				.collect(),
+		}),
 	]))
 }
 
@@ -89,6 +105,10 @@ pub(crate) async fn login_route(
 		},
 	};
 
+	if !services.users.is_active_local(&user_id).await {
+		return Err!(Request(UserDeactivated("This user has been deactivated.")));
+	}
+
 	// Generate a new token for the device
 	let (access_token, expires_in) = services
 		.users

src/api/client/session/sso.rs

@@ -0,0 +1,601 @@
+use std::time::Duration;
+
+use axum::extract::State;
+use axum_client_ip::InsecureClientIp;
+use axum_extra::extract::cookie::{Cookie, SameSite};
+use base64::{Engine as _, engine::general_purpose::URL_SAFE_NO_PAD as b64};
+use futures::{StreamExt, TryFutureExt, future::try_join};
+use itertools::Itertools;
+use reqwest::header::{CONTENT_TYPE, HeaderValue};
+use ruma::{
+	Mxc, OwnedRoomId, OwnedUserId, ServerName, UserId,
+	api::client::session::{sso_callback, sso_login, sso_login_with_provider},
+};
+use serde::{Deserialize, Serialize};
+use tuwunel_core::{
+	Err, Result, at,
+	debug::INFO_SPAN_LEVEL,
+	debug_info, debug_warn, err, info, utils,
+	utils::{
+		content_disposition::make_content_disposition,
+		hash::sha256,
+		result::{FlatOk, LogErr},
+		string::{EMPTY, truncate_deterministic},
+		timepoint_from_now, timepoint_has_passed,
+	},
+	warn,
+};
+use tuwunel_service::{
+	Services,
+	media::MXC_LENGTH,
+	oauth::{
+		CODE_VERIFIER_LENGTH, Provider, SESSION_ID_LENGTH, Session, UserInfo, unique_id,
+		unique_id_sub,
+	},
+	users::Register,
+};
+use url::Url;
+
+use super::TOKEN_LENGTH;
+use crate::Ruma;
+
+/// Grant phase query string.
+#[derive(Debug, Serialize)]
+struct GrantQuery<'a> {
+	client_id: &'a str,
+	state: &'a str,
+	nonce: &'a str,
+	scope: &'a str,
+	response_type: &'a str,
+	access_type: &'a str,
+	code_challenge_method: &'a str,
+	code_challenge: &'a str,
+	redirect_uri: Option<&'a str>,
+}
+
+#[derive(Debug, Deserialize, Serialize)]
+struct GrantCookie<'a> {
+	client_id: &'a str,
+	state: &'a str,
+	nonce: &'a str,
+	redirect_uri: &'a str,
+}
+
+static GRANT_SESSION_COOKIE: &str = "tuwunel_grant_session";
+
+#[tracing::instrument(
+	name = "sso_login",
+	level = "debug",
+	skip_all,
+	fields(%client),
+)]
+pub(crate) async fn sso_login_route(
+	State(_services): State<crate::State>,
+	InsecureClientIp(client): InsecureClientIp,
+	_body: Ruma<sso_login::v3::Request>,
+) -> Result<sso_login::v3::Response> {
+	Err!(Request(NotImplemented(
+		"SSO login without specific provider has not been implemented."
+	)))
+}
+
+#[tracing::instrument(
+	name = "sso_login_with_provider",
+	level = "info",
+	skip_all,
+	ret(level = "debug")
+	fields(
+		%client,
+		idp_id = body.body.idp_id,
+	),
+)]
+pub(crate) async fn sso_login_with_provider_route(
+	State(services): State<crate::State>,
+	InsecureClientIp(client): InsecureClientIp,
+	body: Ruma<sso_login_with_provider::v3::Request>,
+) -> Result<sso_login_with_provider::v3::Response> {
+	let sso_login_with_provider::v3::Request { idp_id, redirect_url } = body.body;
+	let Ok(redirect_url) = redirect_url.parse::<Url>() else {
+		return Err!(Request(InvalidParam("Invalid redirect_url")));
+	};
+
+	let provider = services.oauth.providers.get(&idp_id).await?;
+	let sess_id = utils::random_string(SESSION_ID_LENGTH);
+	let query_nonce = utils::random_string(CODE_VERIFIER_LENGTH);
+	let cookie_nonce = utils::random_string(CODE_VERIFIER_LENGTH);
+	let code_verifier = utils::random_string(CODE_VERIFIER_LENGTH);
+	let code_challenge = b64.encode(sha256::hash(code_verifier.as_bytes()));
+	let callback_uri = provider.callback_url.as_ref().map(Url::as_str);
+	let scope = provider.scope.iter().join(" ");
+
+	let query = GrantQuery {
+		client_id: &provider.client_id,
+		state: &sess_id,
+		nonce: &query_nonce,
+		access_type: "online",
+		response_type: "code",
+		code_challenge_method: "S256",
+		code_challenge: &code_challenge,
+		redirect_uri: callback_uri,
+		scope: scope
+			.is_empty()
+			.then_some("openid email profile")
+			.unwrap_or(scope.as_str()),
+	};
+
+	let location = provider
+		.authorization_url
+		.clone()
+		.map(|mut location| {
+			let query = serde_html_form::to_string(&query).ok();
+			location.set_query(query.as_deref());
+			location
+		})
+		.ok_or_else(|| {
+			err!(Config("authorization_url", "Missing required IdentityProvider config"))
+		})?;
+
+	let cookie_val = GrantCookie {
+		client_id: query.client_id,
+		state: query.state,
+		nonce: &cookie_nonce,
+		redirect_uri: redirect_url.as_str(),
+	};
+
+	let cookie_path = provider
+		.callback_url
+		.as_ref()
+		.map(Url::path)
+		.unwrap_or("/");
+
+	let cookie_max_age = provider
+		.grant_session_duration
+		.map(Duration::from_secs)
+		.expect("Defaulted to Some value during configure_idp()")
+		.try_into()
+		.expect("std::time::Duration to time::Duration conversion failure");
+
+	let cookie = Cookie::build((GRANT_SESSION_COOKIE, serde_html_form::to_string(&cookie_val)?))
+		.path(cookie_path)
+		.max_age(cookie_max_age)
+		.same_site(SameSite::None)
+		.secure(true)
+		.http_only(true)
+		.build()
+		.to_string()
+		.into();
+
+	let session = Session {
+		idp_id: Some(idp_id),
+		sess_id: Some(sess_id.clone()),
+		redirect_url: Some(redirect_url),
+		code_verifier: Some(code_verifier),
+		query_nonce: Some(query_nonce),
+		cookie_nonce: Some(cookie_nonce),
+		authorize_expires_at: provider
+			.grant_session_duration
+			.map(Duration::from_secs)
+			.map(timepoint_from_now)
+			.transpose()?,
+
+		..Default::default()
+	};
+
+	services
+		.oauth
+		.sessions
+		.put(&sess_id, &session)
+		.await;
+
+	Ok(sso_login_with_provider::v3::Response {
+		location: location.into(),
+		cookie: Some(cookie),
+	})
+}
+
+#[tracing::instrument(
+	name = "sso_callback"
+	level = "debug",
+	skip_all,
+	fields(
+		%client,
+		cookie = ?body.cookie,
+		body = ?body.body,
+	),
+)]
+pub(crate) async fn sso_callback_route(
+	State(services): State<crate::State>,
+	InsecureClientIp(client): InsecureClientIp,
+	body: Ruma<sso_callback::unstable::Request>,
+) -> Result<sso_callback::unstable::Response> {
+	let sess_id = body
+		.body
+		.state
+		.as_deref()
+		.ok_or_else(|| err!(Request(Forbidden("Missing sess_id in callback."))))?;
+
+	let code = body
+		.body
+		.code
+		.as_deref()
+		.ok_or_else(|| err!(Request(Forbidden("Missing code in callback."))))?;
+
+	let session = services
+		.oauth
+		.sessions
+		.get(sess_id)
+		.map_err(|_| err!(Request(Forbidden("Invalid state in callback"))));
+
+	let idp_id = body.body.idp_id.as_str();
+	let provider = services.oauth.providers.get(idp_id);
+	let (provider, session) = try_join(provider, session).await.log_err()?;
+	let client_id = &provider.client_id;
+
+	if session.idp_id.as_deref() != Some(idp_id) {
+		return Err!(Request(Unauthorized("Identity Provider {idp_id} session not recognized.")));
+	}
+
+	if session
+		.authorize_expires_at
+		.map(timepoint_has_passed)
+		.unwrap_or(false)
+	{
+		return Err!(Request(Unauthorized("Authorization grant session has expired.")));
+	}
+
+	let cookie = body
+		.cookie
+		.get(GRANT_SESSION_COOKIE)
+		.map(Cookie::value)
+		.map(serde_html_form::from_str::<GrantCookie<'_>>)
+		.transpose()?
+		.ok_or_else(|| err!(Request(Unauthorized("Missing cookie {GRANT_SESSION_COOKIE:?}"))))?;
+
+	if cookie.client_id != client_id {
+		return Err!(Request(Unauthorized("Client ID {client_id:?} cookie mismatch.")));
+	}
+
+	if Some(cookie.nonce) != session.cookie_nonce.as_deref() {
+		return Err!(Request(Unauthorized("Cookie nonce does not match session state.")));
+	}
+
+	if cookie.state != sess_id {
+		return Err!(Request(Unauthorized("Session ID {sess_id:?} cookie mismatch.")));
+	}
+
+	// Request access token.
+	let token_response = services
+		.oauth
+		.request_token((&provider, &session), code)
+		.await?;
+
+	let token_expires_at = token_response
+		.expires_in
+		.map(Duration::from_secs)
+		.map(timepoint_from_now)
+		.transpose()?;
+
+	let refresh_token_expires_at = token_response
+		.refresh_token_expires_in
+		.map(Duration::from_secs)
+		.map(timepoint_from_now)
+		.transpose()?;
+
+	// Update the session with access token results
+	let session = Session {
+		scope: token_response.scope,
+		token_type: token_response.token_type,
+		access_token: token_response.access_token,
+		expires_at: token_expires_at,
+		refresh_token: token_response.refresh_token,
+		refresh_token_expires_at,
+		..session
+	};
+
+	// Request userinfo claims.
+	let userinfo = services
+		.oauth
+		.request_userinfo((&provider, &session))
+		.await?;
+
+	// Check for an existing session from this identity. We want to maintain one
+	// session for each identity and keep the newer one which has up-to-date state
+	// and access.
+	let (user_id, old_sess_id) = match services
+		.oauth
+		.sessions
+		.get_by_unique_id(&unique_id_sub((&provider, &userinfo.sub))?)
+		.await
+	{
+		| Ok(session) => (session.user_id, session.sess_id),
+		| Err(error) if !error.is_not_found() => return Err(error),
+		| Err(_) => (None, None),
+	};
+
+	// Update the session with userinfo
+	let session = Session {
+		user_info: Some(userinfo.clone()),
+		..session
+	};
+
+	// Keep the user_id from the old session as best as possible.
+	let user_id = match user_id {
+		| Some(user_id) => user_id,
+		| None => decide_user_id(&services, &provider, &session, &userinfo).await?,
+	};
+
+	// Update the session with user_id
+	let session = Session {
+		user_id: Some(user_id.clone()),
+		..session
+	};
+
+	// Attempt to register a non-existing user.
+	if !services.users.exists(&user_id).await {
+		register_user(&services, &provider, &session, &userinfo, &user_id).await?;
+	}
+
+	// Commit the updated session.
+	services
+		.oauth
+		.sessions
+		.put(sess_id, &session)
+		.await;
+
+	// Delete any old session.
+	if let Some(old_sess_id) = old_sess_id
+		&& sess_id != old_sess_id
+	{
+		services.oauth.sessions.delete(&old_sess_id).await;
+	}
+
+	if !services.users.is_active_local(&user_id).await {
+		return Err!(Request(UserDeactivated("This user has been deactivated.")));
+	}
+
+	// Allow the user to login to Matrix.
+	let login_token = utils::random_string(TOKEN_LENGTH);
+	let _login_token_expires_in = services
+		.users
+		.create_login_token(&user_id, &login_token);
+
+	let location = session
+		.redirect_url
+		.as_ref()
+		.ok_or_else(|| err!(Request(InvalidParam("Missing redirect URL in session data"))))?
+		.clone()
+		.query_pairs_mut()
+		.append_pair("loginToken", &login_token)
+		.finish()
+		.to_string();
+
+	let cookie = Cookie::build((GRANT_SESSION_COOKIE, EMPTY))
+		.removal()
+		.build()
+		.to_string()
+		.into();
+
+	Ok(sso_callback::unstable::Response { location, cookie: Some(cookie) })
+}
+
+#[tracing::instrument(
+	name = "register",
+	level = INFO_SPAN_LEVEL,
+	skip_all,
+	fields(user_id, userinfo)
+)]
+async fn register_user(
+	services: &Services,
+	provider: &Provider,
+	session: &Session,
+	userinfo: &UserInfo,
+	user_id: &UserId,
+) -> Result {
+	debug_info!(%user_id, "Creating new user account...");
+
+	services
+		.users
+		.full_register(Register {
+			user_id: Some(user_id),
+			password: Some("*"),
+			origin: Some("sso"),
+			displayname: userinfo.name.as_deref(),
+			..Default::default()
+		})
+		.await?;
+
+	if let Some(avatar_url) = userinfo
+		.avatar_url
+		.as_deref()
+		.or(userinfo.picture.as_deref())
+	{
+		set_avatar(services, provider, session, userinfo, user_id, avatar_url)
+			.await
+			.ok();
+	}
+
+	let idp_id = provider.id();
+	let idp_name = provider
+		.name
+		.as_deref()
+		.unwrap_or(provider.brand.as_str());
+
+	// log in conduit admin channel if a non-guest user registered
+	let notice =
+		format!("New user \"{user_id}\" registered on this server via {idp_name} ({idp_id})",);
+
+	info!("{notice}");
+	if services.server.config.admin_room_notices {
+		services.admin.notice(&notice).await;
+	}
+
+	Ok(())
+}
+
+#[tracing::instrument(level = "debug", skip_all, fields(user_id, avatar_url))]
+async fn set_avatar(
+	services: &Services,
+	_provider: &Provider,
+	_session: &Session,
+	_userinfo: &UserInfo,
+	user_id: &UserId,
+	avatar_url: &str,
+) -> Result {
+	use reqwest::Response;
+
+	let response = services
+		.client
+		.default
+		.get(avatar_url)
+		.send()
+		.await
+		.and_then(Response::error_for_status)?;
+
+	let content_type = response
+		.headers()
+		.get(CONTENT_TYPE)
+		.map(HeaderValue::to_str)
+		.flat_ok()
+		.map(ToOwned::to_owned);
+
+	let mxc = Mxc {
+		server_name: services.globals.server_name(),
+		media_id: &utils::random_string(MXC_LENGTH),
+	};
+
+	let content_disposition = make_content_disposition(None, content_type.as_deref(), None);
+	let bytes = response.bytes().await?;
+	services
+		.media
+		.create(&mxc, Some(user_id), Some(&content_disposition), content_type.as_deref(), &bytes)
+		.await?;
+
+	let all_joined_rooms: Vec<OwnedRoomId> = services
+		.state_cache
+		.rooms_joined(user_id)
+		.map(ToOwned::to_owned)
+		.collect()
+		.await;
+
+	let mxc_uri = mxc.to_string().into();
+	services
+		.users
+		.update_avatar_url(user_id, Some(mxc_uri), None, &all_joined_rooms)
+		.await;
+
+	Ok(())
+}
+
+#[tracing::instrument(
+	level = "debug",
+	ret(level = "debug")
+	skip_all,
+	fields(user),
+)]
+async fn decide_user_id(
+	services: &Services,
+	provider: &Provider,
+	session: &Session,
+	userinfo: &UserInfo,
+) -> Result<OwnedUserId> {
+	let allowed =
+		|claim: &str| provider.userid_claims.is_empty() || provider.userid_claims.contains(claim);
+
+	let choices = [
+		userinfo
+			.preferred_username
+			.as_deref()
+			.map(str::to_lowercase)
+			.filter(|_| allowed("preferred_username")),
+		userinfo
+			.nickname
+			.as_deref()
+			.map(str::to_lowercase)
+			.filter(|_| allowed("nickname")),
+		provider
+			.brand
+			.eq(&"github")
+			.then_some(userinfo.sub.as_str())
+			.map(str::to_lowercase)
+			.filter(|_| allowed("login")),
+		userinfo
+			.email
+			.as_deref()
+			.and_then(|email| email.split_once('@'))
+			.map(at!(0))
+			.map(str::to_lowercase)
+			.filter(|_| allowed("email")),
+	];
+
+	for choice in choices.into_iter().flatten() {
+		if let Some(user_id) = try_user_id(services, &choice, false).await {
+			return Ok(user_id);
+		}
+	}
+
+	if let Ok(infallible) = unique_id((provider, session))
+		.map(|h| truncate_deterministic(&h, Some(15..23)).to_lowercase())
+		.log_err()
+	{
+		if let Some(user_id) = try_user_id(services, &infallible, true).await {
+			return Ok(user_id);
+		}
+	}
+
+	Err!(Request(UserInUse("User ID is not available.")))
+}
+
+#[tracing::instrument(level = "debug", skip_all, fields(username))]
+async fn try_user_id(
+	services: &Services,
+	username: &str,
+	may_exist: bool,
+) -> Option<OwnedUserId> {
+	let server_name = services.globals.server_name();
+	let user_id = parse_user_id(server_name, username)
+		.inspect_err(|e| warn!(?username, "Username invalid: {e}"))
+		.ok()?;
+
+	if services
+		.config
+		.forbidden_usernames
+		.is_match(username)
+	{
+		warn!(?username, "Username forbidden.");
+		return None;
+	}
+
+	if services.users.exists(&user_id).await {
+		debug_warn!(?username, "Username exists.");
+
+		if services
+			.users
+			.origin(&user_id)
+			.await
+			.ok()
+			.is_none_or(|origin| origin != "sso")
+		{
+			debug_warn!(?username, "Username has non-sso origin.");
+			return None;
+		}
+
+		if !may_exist {
+			return None;
+		}
+	}
+
+	Some(user_id)
+}
+
+fn parse_user_id(server_name: &ServerName, username: &str) -> Result<OwnedUserId> {
+	match UserId::parse_with_server_name(username, server_name) {
+		| Err(e) =>
+			Err!(Request(InvalidUsername(debug_error!("Username {username} is not valid: {e}")))),
+		| Ok(user_id) => match user_id.validate_strict() {
+			| Ok(()) => Ok(user_id),
+			| Err(e) => Err!(Request(InvalidUsername(debug_error!(
+				"Username {username} contains disallowed characters or spaces: {e}"
+			)))),
+		},
+	}
+}