feat(oauth): Add option to logout from OpenID Connect provider

* Fixes #598

Signed-off-by: Marvin A. Ruder <signed@mruder.dev>

backend/prisma/migrations/20241007181823_oauth_id_token/migration.sql

@@ -0,0 +1,2 @@
+-- AlterTable
+ALTER TABLE "RefreshToken" ADD COLUMN "oauthIDToken" TEXT;

backend/prisma/schema.prisma

@@ -40,6 +40,8 @@ model RefreshToken {
 
   userId String
   user   User   @relation(fields: [userId], references: [id], onDelete: Cascade)
+
+  oauthIDToken  String? // prefixed with the ID of the issuing OAuth provider, separated by a colon
 }
 
 model LoginToken {

backend/prisma/seed/config.seed.ts

@@ -275,6 +275,10 @@ const configVariables: ConfigVariables = {
       type: "string",
       defaultValue: "",
     },
+    "oidc-signOut": {
+      type: "boolean",
+      defaultValue: "false",
+    },
     "oidc-usernameClaim": {
       type: "string",
       defaultValue: "",

backend/src/auth/auth.controller.ts

@@ -172,10 +172,10 @@ export class AuthController {
     @Req() request: Request,
     @Res({ passthrough: true }) response: Response,
   ) {
-    await this.authService.signOut(request.cookies.access_token);
+    const redirectURI = await this.authService.signOut(request.cookies.access_token);
 
     const isSecure = this.config.get("general.appUrl").startsWith("https");
-    response.cookie("access_token", "accessToken", {
+    response.cookie("access_token", "", {
       maxAge: -1,
       secure: isSecure,
     });
@@ -185,6 +185,10 @@ export class AuthController {
       maxAge: -1,
       secure: isSecure,
     });
+
+    if (typeof redirectURI === "string") {
+      return { redirectURI: redirectURI.toString() };
+    }
   }
 
   @Post("totp/enable")

backend/src/auth/auth.module.ts

@@ -1,4 +1,4 @@
-import { Module } from "@nestjs/common";
+import { forwardRef, Module } from "@nestjs/common";
 import { JwtModule } from "@nestjs/jwt";
 import { EmailModule } from "src/email/email.module";
 import { AuthController } from "./auth.controller";
@@ -7,6 +7,7 @@ import { AuthTotpService } from "./authTotp.service";
 import { JwtStrategy } from "./strategy/jwt.strategy";
 import { LdapService } from "./ldap.service";
 import { UserModule } from "../user/user.module";
+import { OAuthModule } from "../oauth/oauth.module";
 
 @Module({
   imports: [
@@ -14,6 +15,7 @@ import { UserModule } from "../user/user.module";
       global: true,
     }),
     EmailModule,
+    forwardRef(() => OAuthModule),
     UserModule,
   ],
   controllers: [AuthController],

backend/src/auth/auth.service.ts

@@ -1,6 +1,8 @@
 import {
   BadRequestException,
   ForbiddenException,
+  forwardRef,
+  Inject,
   Injectable,
   Logger,
   UnauthorizedException,
@@ -17,7 +19,8 @@ import { PrismaService } from "src/prisma/prisma.service";
 import { AuthRegisterDTO } from "./dto/authRegister.dto";
 import { AuthSignInDTO } from "./dto/authSignIn.dto";
 import { LdapService } from "./ldap.service";
-import { inspect } from "util";
+import { GenericOidcProvider } from "../oauth/provider/genericOidc.provider";
+import { OAuthService } from "../oauth/oauth.service";
 import { UserSevice } from "../user/user.service";
 
 @Injectable()
@@ -29,6 +32,7 @@ export class AuthService {
     private emailService: EmailService,
     private ldapService: LdapService,
     private userService: UserSevice,
+    @Inject(forwardRef(() => OAuthService)) private oAuthService: OAuthService,
   ) {}
   private readonly logger = new Logger(AuthService.name);
 
@@ -113,12 +117,12 @@ export class AuthService {
     throw new UnauthorizedException("Wrong email or password");
   }
 
-  async generateToken(user: User, isOAuth = false) {
+  async generateToken(user: User, oauth?: { idToken?: string }) {
     // TODO: Make all old loginTokens invalid when a new one is created
     // Check if the user has TOTP enabled
     if (
       user.totpVerified &&
-      !(isOAuth && this.config.get("oauth.ignoreTotp"))
+      !(oauth && this.config.get("oauth.ignoreTotp"))
     ) {
       const loginToken = await this.createLoginToken(user.id);
 
@@ -127,6 +131,7 @@ export class AuthService {
 
     const { refreshToken, refreshTokenId } = await this.createRefreshToken(
       user.id,
+      oauth?.idToken,
     );
     const accessToken = await this.createAccessToken(user, refreshTokenId);
 
@@ -225,12 +230,39 @@ export class AuthService {
       }) || {};
 
     if (refreshTokenId) {
+      const oauthIDToken = await this.prisma.refreshToken
+        .findFirst({ select: { oauthIDToken: true }, where: { id: refreshTokenId } })
+        .then((refreshToken) => refreshToken?.oauthIDToken)
+        .catch((e) => {
+          // Ignore error if refresh token doesn't exist
+          if (e.code != "P2025") throw e;
+        });
       await this.prisma.refreshToken
         .delete({ where: { id: refreshTokenId } })
         .catch((e) => {
           // Ignore error if refresh token doesn't exist
           if (e.code != "P2025") throw e;
         });
+
+      if (typeof oauthIDToken === "string") {
+        const [providerName, idTokenHint] = oauthIDToken.split(":");
+        const provider = this.oAuthService.availableProviders()[providerName];
+        let signOutFromProviderSupportedAndActivated = false;
+        try {
+          signOutFromProviderSupportedAndActivated = this.config.get(`oauth.${providerName}-signOut`);
+        } catch (_) {
+          // Ignore error if the provider is not supported or if the provider sign out is not activated
+        }
+        if (provider instanceof GenericOidcProvider && signOutFromProviderSupportedAndActivated) {
+          const configuration =  await provider.getConfiguration();
+          if (configuration.frontchannel_logout_supported && URL.canParse(configuration.end_session_endpoint)) {
+            const redirectURI = new URL(configuration.end_session_endpoint);
+            redirectURI.searchParams.append("id_token_hint", idTokenHint);
+            redirectURI.searchParams.append("client_id", this.config.get(`oauth.${providerName}-clientId`));
+            return redirectURI.toString();
+          }
+        }
+      }
     }
   }
 
@@ -249,13 +281,14 @@ export class AuthService {
     );
   }
 
-  async createRefreshToken(userId: string) {
+  async createRefreshToken(userId: string, idToken?: string) {
     const { id, token } = await this.prisma.refreshToken.create({
       data: {
         userId,
         expiresAt: moment()
           .add(this.config.get("general.sessionDuration"), "hours")
           .toDate(),
+        oauthIDToken: idToken,
       },
     });
 

backend/src/oauth/dto/oauthSignIn.dto.ts

@@ -4,4 +4,5 @@ export interface OAuthSignInDto {
   providerUsername: string;
   email: string;
   isAdmin?: boolean;
+  idToken?: string;
 }

backend/src/oauth/oauth.module.ts

@@ -1,4 +1,4 @@
-import { Module } from "@nestjs/common";
+import { forwardRef, Module } from "@nestjs/common";
 import { OAuthController } from "./oauth.controller";
 import { OAuthService } from "./oauth.service";
 import { AuthModule } from "../auth/auth.module";
@@ -51,6 +51,7 @@ import { MicrosoftProvider } from "./provider/microsoft.provider";
       inject: ["OAUTH_PROVIDERS"],
     },
   ],
-  imports: [AuthModule],
+  imports: [forwardRef(() => AuthModule)],
+  exports: [OAuthService],
 })
 export class OAuthModule {}

backend/src/oauth/oauth.service.ts

@@ -1,4 +1,4 @@
-import { Inject, Injectable, Logger } from "@nestjs/common";
+import { forwardRef, Inject, Injectable, Logger } from "@nestjs/common";
 import { User } from "@prisma/client";
 import { nanoid } from "nanoid";
 import { AuthService } from "../auth/auth.service";
@@ -6,14 +6,16 @@ import { ConfigService } from "../config/config.service";
 import { PrismaService } from "../prisma/prisma.service";
 import { OAuthSignInDto } from "./dto/oauthSignIn.dto";
 import { ErrorPageException } from "./exceptions/errorPage.exception";
+import { OAuthProvider } from "./provider/oauthProvider.interface";
 
 @Injectable()
 export class OAuthService {
   constructor(
     private prisma: PrismaService,
     private config: ConfigService,
-    private auth: AuthService,
+    @Inject(forwardRef(() => AuthService)) private auth: AuthService,
     @Inject("OAUTH_PLATFORMS") private platforms: string[],
+    @Inject("OAUTH_PROVIDERS") private oAuthProviders: Record<string, OAuthProvider<unknown>>,
   ) {}
   private readonly logger = new Logger(OAuthService.name);
 
@@ -27,6 +29,16 @@ export class OAuthService {
       .map(([platform, _]) => platform);
   }
 
+  availableProviders(): Record<string, OAuthProvider<unknown>> {
+    return Object.fromEntries(Object.entries(this.oAuthProviders)
+      .map(([providerName, provider]) => [
+        [providerName, provider],
+        this.config.get(`oauth.${providerName}-enabled`),
+      ])
+      .filter(([_, enabled]) => enabled)
+      .map(([provider, _]) => provider));
+  }
+
   async status(user: User) {
     const oauthUsers = await this.prisma.oAuthUser.findMany({
       select: {
@@ -55,7 +67,7 @@ export class OAuthService {
         },
       });
       this.logger.log(`Successful login for user ${user.email} from IP ${ip}`);
-      return this.auth.generateToken(updatedUser, true);
+      return this.auth.generateToken(updatedUser, { idToken: user.idToken });
     }
 
     return this.signUp(user, ip);
@@ -156,7 +168,7 @@ export class OAuthService {
         },
       });
       await this.updateIsAdmin(user);
-      return this.auth.generateToken(existingUser, true);
+      return this.auth.generateToken(existingUser, { idToken: user.idToken });
     }
 
     const result = await this.auth.signUp(

backend/src/oauth/provider/discord.provider.ts

@@ -91,6 +91,7 @@ export class DiscordProvider implements OAuthProvider<DiscordToken> {
       providerId: user.id,
       providerUsername: user.global_name ?? user.username,
       email: user.email,
+      idToken: `discord:${token.idToken}`,
     };
   }
 

backend/src/oauth/provider/genericOidc.provider.ts

@@ -197,6 +197,7 @@ export abstract class GenericOidcProvider implements OAuthProvider<OidcToken> {
       providerId: idTokenData.sub,
       providerUsername: username,
       ...(isAdmin !== undefined && { isAdmin }),
+      idToken: `${this.name}:${token.idToken}`,
     };
   }
 
@@ -251,6 +252,8 @@ export interface OidcConfiguration {
   id_token_signing_alg_values_supported: string[];
   scopes_supported?: string[];
   claims_supported?: string[];
+  frontchannel_logout_supported?: boolean;
+  end_session_endpoint?: string;
 }
 
 export interface OidcJwk {

backend/src/oauth/provider/github.provider.ts

@@ -61,6 +61,7 @@ export class GitHubProvider implements OAuthProvider<GitHubToken> {
       providerId: user.id.toString(),
       providerUsername: user.name ?? user.login,
       email,
+      idToken: `github:${token.idToken}`,
     };
   }
 

frontend/src/i18n/translations/de-DE.ts

@@ -392,6 +392,8 @@ export default {
   "admin.config.oauth.oidc-enabled.description": "OpenID Connect Anmeldung erlaubt",
   "admin.config.oauth.oidc-discovery-uri": "OpenID Verbindung Discovery URL",
   "admin.config.oauth.oidc-discovery-uri.description": "Discovery-URL der OpenID OAuth App",
+  "admin.config.oauth.oidc-sign-out": "Abmelden von OpenID Connect",
+  "admin.config.oauth.oidc-sign-out.description": "Wenn aktiviert, wird der Benutzer mit der „Abmelden“-Schaltfläche vom OpenID-Connect-Provider abgemeldet.",
   "admin.config.oauth.oidc-username-claim": "OpenID Connect Benutzername anfordern",
   "admin.config.oauth.oidc-username-claim.description": "Benutzername im OpenID Token. Leer lassen, wenn du nicht weißt, was diese Konfiguration bedeutet.",
   "admin.config.oauth.oidc-role-path": "Path to roles in OpenID Connect token",

frontend/src/i18n/translations/en-US.ts

@@ -547,6 +547,9 @@ export default {
   "admin.config.oauth.oidc-discovery-uri": "OpenID Connect Discovery URI",
   "admin.config.oauth.oidc-discovery-uri.description":
     "Discovery URI of the OpenID Connect OAuth app",
+  "admin.config.oauth.oidc-sign-out": "Sign out from OpenID Connect",
+  "admin.config.oauth.oidc-sign-out.description":
+    "Whether the “Sign out” button will sign out from the OpenID Connect provider",
   "admin.config.oauth.oidc-username-claim": "OpenID Connect username claim",
   "admin.config.oauth.oidc-username-claim.description":
     "Username claim in OpenID Connect ID token. Leave it blank if you don't know what this config is.",

frontend/src/services/auth.service.ts

@@ -29,8 +29,10 @@ const signUp = async (email: string, username: string, password: string) => {
 };
 
 const signOut = async () => {
-  await api.post("/auth/signOut");
-  window.location.reload();
+  const response = await api.post("/auth/signOut");
+
+  if (URL.canParse(response.data?.redirectURI)) window.location.href = response.data.redirectURI;
+  else window.location.reload();
 };
 
 const refreshAccessToken = async () => {