Add native OIDC support in Grist #707 (#717)

app/server/lib/BrowserSession.ts

@@ -68,6 +68,11 @@ export interface SessionObj {
                           // anonymous editing (e.g. to allow the user to edit
                           // something they just added, without allowing the suer
                           // to edit other people's contributions).
+
+  oidc?: {
+    // codeVerifier is used during OIDC authentication, to protect against attacks like CSRF.
+    codeVerifier?: string;
+  }
 }
 
 // Make an artificial change to a session to encourage express-session to set a cookie.

app/server/lib/OIDCConfig.ts

@@ -0,0 +1,187 @@
+/**
+ * Configuration for OpenID Connect (OIDC), useful for enterprise single-sign-on logins.
+ * A good informative overview of OIDC is at https://developer.okta.com/blog/2019/10/21/illustrated-guide-to-oauth-and-oidc
+ * Note:
+ *    SP is "Service Provider", in our case, the Grist application.
+ *    IdP is the "Identity Provider", somewhere users log into, e.g. Okta or Google Apps.
+ *
+ * We also use optional attributes for the user's name, for which we accept any of:
+ *    given_name
+ *    family_name
+ *
+ * Expected environment variables:
+ *    env GRIST_OIDC_SP_HOST=https://<your-domain>
+ *        Host at which our /oauth2 endpoint will live. Optional, defaults to `APP_HOME_URL`.
+ *    env GRIST_OIDC_IDP_ISSUER
+ *        The issuer URL for the IdP, passed to node-openid-client, see: https://github.com/panva/node-openid-client/blob/a84d022f195f82ca1c97f8f6b2567ebcef8738c3/docs/README.md#issuerdiscoverissuer.
+ *        This variable turns on the OIDC login system.
+ *    env GRIST_OIDC_IDP_CLIENT_ID
+ *        The client ID for the application, as registered with the IdP.
+ *    env GRIST_OIDC_IDP_CLIENT_SECRET
+ *        The client secret for the application, as registered with the IdP.
+ *    env GRIST_OIDC_IDP_SCOPES
+ *        The scopes to request from the IdP, as a space-separated list. Defaults to "openid email profile".
+ *
+ * This version of OIDCConfig has been tested with Keycloak OIDC IdP following the instructions
+ * at:
+ *   https://www.keycloak.org/getting-started/getting-started-docker
+ *
+ * /!\ CAUTION: For production, be sure to use https for all URLs. /!\
+ *
+ * For development of this module on localhost, these settings should work:
+ *   - GRIST_OIDC_SP_HOST=http://localhost:8484 (or whatever port you use for Grist)
+ *   - GRIST_OIDC_IDP_ISSUER=http://localhost:8080/realms/myrealm (replace 8080 by the port you use for keycloak)
+ *   - GRIST_OIDC_IDP_CLIENT_ID=my_grist_instance
+ *   - GRIST_OIDC_IDP_CLIENT_SECRET=YOUR_SECRET (as set in keycloak)
+ *   - GRIST_OIDC_IDP_SCOPES="openid email profile"
+ */
+
+import * as express from 'express';
+import { GristLoginSystem, GristServer } from './GristServer';
+import { Client, generators, Issuer, UserinfoResponse } from 'openid-client';
+import { Sessions } from './Sessions';
+import log from 'app/server/lib/log';
+import { appSettings } from './AppSettings';
+import { RequestWithLogin } from './Authorizer';
+
+const CALLBACK_URL = '/oauth2/callback';
+
+export class OIDCConfig {
+  private _client: Client;
+  private _redirectUrl: string;
+
+  public constructor() {
+  }
+
+  public async initOIDC(): Promise<void> {
+    const section = appSettings.section('login').section('system').section('oidc');
+    const spHost = section.flag('spHost').requireString({
+      envVar: 'GRIST_OIDC_SP_HOST',
+      defaultValue: process.env.APP_HOME_URL,
+    });
+    const issuerUrl = section.flag('issuer').requireString({
+      envVar: 'GRIST_OIDC_IDP_ISSUER',
+    });
+    const clientId = section.flag('clientId').requireString({
+      envVar: 'GRIST_OIDC_IDP_CLIENT_ID',
+    });
+    const clientSecret = section.flag('clientSecret').requireString({
+      envVar: 'GRIST_OIDC_IDP_CLIENT_SECRET',
+      censor: true,
+    });
+
+    const issuer = await Issuer.discover(issuerUrl);
+    this._redirectUrl = new URL(CALLBACK_URL, spHost).href;
+    this._client = new issuer.Client({
+      client_id: clientId,
+      client_secret: clientSecret,
+      redirect_uris: [ this._redirectUrl ],
+      response_types: [ 'code' ],
+    });
+  }
+
+  public addEndpoints(app: express.Application, sessions: Sessions): void {
+    app.get(CALLBACK_URL, this.handleCallback.bind(this, sessions));
+  }
+
+  public async handleCallback(sessions: Sessions, req: express.Request, res: express.Response): Promise<void> {
+    try {
+      const params = this._client.callbackParams(req);
+      const { state } = params;
+      if (!state) {
+        throw new Error('Login or logout failed to complete');
+      }
+
+      const codeVerifier = await this._retrieveCodeVerifierFromSession(req);
+
+      const tokenSet = await this._client.callback(
+        this._redirectUrl,
+        params,
+        { state, code_verifier: codeVerifier }
+      );
+
+      const userInfo = await this._client.userinfo(tokenSet);
+      const profile = this._makeUserProfileFromUserInfo(userInfo);
+
+      const scopedSession = sessions.getOrCreateSessionFromRequest(req);
+      await scopedSession.operateOnScopedSession(req, async (user) => Object.assign(user, {
+        profile,
+      }));
+
+      res.redirect('/');
+    } catch (err) {
+      log.error(`OIDC callback failed: ${err.message}`);
+      res.status(500).send(`OIDC callback failed: ${err.message}`);
+    }
+  }
+
+  public async getLoginRedirectUrl(req: express.Request): Promise<string> {
+    const codeVerifier = await this._generateAndStoreCodeVerifier(req);
+    const codeChallenge = generators.codeChallenge(codeVerifier);
+    const state = generators.state();
+
+    const authUrl = this._client.authorizationUrl({
+      scope: process.env.GRIST_OIDC_IDP_SCOPES || 'openid email profile',
+      code_challenge: codeChallenge,
+      code_challenge_method: 'S256',
+      state,
+    });
+    return authUrl;
+  }
+
+  public async getLogoutRedirectUrl(req: express.Request, redirectUrl: URL): Promise<string> {
+    return this._client.endSessionUrl({
+      post_logout_redirect_uri: redirectUrl.href
+    });
+  }
+
+  private async _generateAndStoreCodeVerifier(req: express.Request) {
+    const mreq = req as RequestWithLogin;
+    if (!mreq.session) { throw new Error('no session available'); }
+    const codeVerifier = generators.codeVerifier();
+    mreq.session.oidc = {
+      codeVerifier,
+    };
+
+    return codeVerifier;
+  }
+
+  private async _retrieveCodeVerifierFromSession(req: express.Request) {
+    const mreq = req as RequestWithLogin;
+    if (!mreq.session) { throw new Error('no session available'); }
+    const codeVerifier = mreq.session.oidc?.codeVerifier;
+    if (!codeVerifier) { throw new Error('Login is stale'); }
+    delete mreq.session.oidc?.codeVerifier;
+    return codeVerifier;
+  }
+
+  private _makeUserProfileFromUserInfo(userInfo: UserinfoResponse) {
+      const email = userInfo.email;
+      const fname = userInfo.given_name ?? '';
+      const lname = userInfo.family_name ?? '';
+      return {
+        email,
+        name: `${fname} ${lname}`.trim(),
+      };
+  }
+}
+
+export async function getOIDCLoginSystem(): Promise<GristLoginSystem|undefined> {
+  if (!process.env.GRIST_OIDC_IDP_ISSUER) { return undefined; }
+  return {
+    async getMiddleware(gristServer: GristServer) {
+      const config = new OIDCConfig();
+      await config.initOIDC();
+      return {
+        getLoginRedirectUrl: config.getLoginRedirectUrl.bind(config),
+        getSignUpRedirectUrl: config.getLoginRedirectUrl.bind(config),
+        getLogoutRedirectUrl: config.getLogoutRedirectUrl.bind(config),
+        async addEndpoints(app: express.Express) {
+          config.addEndpoints(app, gristServer.getSessions());
+          return 'oidc';
+        },
+      };
+    },
+    async deleteUser() {},
+  };
+}

package.json

@@ -168,6 +168,7 @@
     "multiparty": "4.2.2",
     "node-abort-controller": "3.0.1",
     "node-fetch": "2.6.7",
+    "openid-client": "^5.6.1",
     "pg": "8.6.0",
     "piscina": "3.2.0",
     "plotly.js-basic-dist": "2.13.2",

stubs/app/server/lib/logins.ts

@@ -1,10 +1,12 @@
 import { getForwardAuthLoginSystem } from 'app/server/lib/ForwardAuthLogin';
 import { GristLoginSystem } from 'app/server/lib/GristServer';
 import { getMinimalLoginSystem } from 'app/server/lib/MinimalLogin';
+import { getOIDCLoginSystem } from 'app/server/lib/OIDCConfig';
 import { getSamlLoginSystem } from 'app/server/lib/SamlConfig';
 
 export async function getLoginSystem(): Promise<GristLoginSystem> {
   return await getSamlLoginSystem() ||
+    await getOIDCLoginSystem() ||
     await getForwardAuthLoginSystem() ||
     await getMinimalLoginSystem();
 }

yarn.lock

@@ -4923,6 +4923,11 @@ jest-worker@^27.4.5:
     merge-stream "^2.0.0"
     supports-color "^8.0.0"
 
+jose@^4.15.1:
+  version "4.15.4"
+  resolved "https://registry.yarnpkg.com/jose/-/jose-4.15.4.tgz#02a9a763803e3872cf55f29ecef0dfdcc218cc03"
+  integrity sha512-W+oqK4H+r5sITxfxpSU+MMdr/YSWGvgZMQDIsNoBDGGy4i7GBPTtvFKibQzW06n3U3TqHjhvBJsirShsEJ6eeQ==
+
 joycon@^3.0.1:
   version "3.1.1"
   resolved "https://registry.npmjs.org/joycon/-/joycon-3.1.1.tgz"
@@ -6067,6 +6072,11 @@ object-assign@^4.0.1, object-assign@^4.1.1:
   resolved "https://registry.npmjs.org/object-assign/-/object-assign-4.1.1.tgz"
   integrity sha1-IQmtx5ZYh8/AXLvUQsrIv7s2CGM=
 
+object-hash@^2.2.0:
+  version "2.2.0"
+  resolved "https://registry.yarnpkg.com/object-hash/-/object-hash-2.2.0.tgz#5ad518581eefc443bd763472b8ff2e9c2c0d54a5"
+  integrity sha512-gScRMn0bS5fH+IuwyIFgnh9zBdo4DV+6GhygmWM9HyNJSgS0hScp1f5vjtm7oIIOiT9trXrShAkLFSc2IqKNgw==
+
 object-inspect@^1.9.0:
   version "1.9.0"
   resolved "https://registry.npmjs.org/object-inspect/-/object-inspect-1.9.0.tgz"
@@ -6087,6 +6097,11 @@ object.assign@^4.0.4:
     has-symbols "^1.0.3"
     object-keys "^1.1.1"
 
+oidc-token-hash@^5.0.3:
+  version "5.0.3"
+  resolved "https://registry.yarnpkg.com/oidc-token-hash/-/oidc-token-hash-5.0.3.tgz#9a229f0a1ce9d4fc89bcaee5478c97a889e7b7b6"
+  integrity sha512-IF4PcGgzAr6XXSff26Sk/+P4KZFJVuHAJZj3wgO3vX2bMdNVp/QXTP3P7CEm9V1IdG8lDLY3HhiqpsE/nOwpPw==
+
 [email protected]:
   version "2.4.1"
   resolved "https://registry.yarnpkg.com/on-finished/-/on-finished-2.4.1.tgz#58c8c44116e54845ad57f14ab10b03533184ac3f"
@@ -6113,6 +6128,16 @@ once@^1.3.0, once@^1.3.1, once@^1.3.2, once@^1.4.0:
   dependencies:
     wrappy "1"
 
+openid-client@^5.6.1:
+  version "5.6.1"
+  resolved "https://registry.yarnpkg.com/openid-client/-/openid-client-5.6.1.tgz#8f7526a50c290a5e28a7fe21b3ece3107511bc73"
+  integrity sha512-PtrWsY+dXg6y8mtMPyL/namZSYVz8pjXz3yJiBNZsEdCnu9miHLB4ELVC85WvneMKo2Rg62Ay7NkuCpM0bgiLQ==
+  dependencies:
+    jose "^4.15.1"
+    lru-cache "^6.0.0"
+    object-hash "^2.2.0"
+    oidc-token-hash "^5.0.3"
+
 optionator@^0.8.1:
   version "0.8.3"
   resolved "https://registry.npmjs.org/optionator/-/optionator-0.8.3.tgz"