feat(auth): implement generic oauth2 provider

plugins/auth-backend/src/providers/factories.ts

@@ -15,14 +15,15 @@
  */
 
 import Router from 'express-promise-router';
-import { createGithubProvider } from './github';
-import { createGoogleProvider } from './google';
-import { createGitlabProvider } from './gitlab';
-import { createSamlProvider } from './saml';
-import { createOktaProvider } from './okta';
-import { AuthProviderFactory, AuthProviderConfig } from './types';
 import { Logger } from 'winston';
 import { TokenIssuer } from '../identity';
+import { createGithubProvider } from './github';
+import { createGitlabProvider } from './gitlab';
+import { createGoogleProvider } from './google';
+import { createOAuth2Provider } from './oauth2';
+import { createOktaProvider } from './okta';
+import { createSamlProvider } from './saml';
+import { AuthProviderConfig, AuthProviderFactory } from './types';
 
 const factories: { [providerId: string]: AuthProviderFactory } = {
   google: createGoogleProvider,
@@ -30,6 +31,7 @@ const factories: { [providerId: string]: AuthProviderFactory } = {
   gitlab: createGitlabProvider,
   saml: createSamlProvider,
   okta: createOktaProvider,
+  oauth2: createOAuth2Provider,
 };
 
 export const createAuthProviderRouter = (

plugins/auth-backend/src/providers/oauth2/index.ts

@@ -0,0 +1,17 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * 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.
+ */
+
+export { createOAuth2Provider } from './provider';

plugins/auth-backend/src/providers/oauth2/provider.ts

@@ -0,0 +1,198 @@
+/*
+ * Copyright 2020 Spotify AB
+ *
+ * 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.
+ */
+
+import express from 'express';
+import passport from 'passport';
+import { Strategy as OAuth2Strategy } from 'passport-oauth2';
+import { Logger } from 'winston';
+import { TokenIssuer } from '../../identity';
+import {
+  EnvironmentHandler,
+  EnvironmentHandlers,
+} from '../../lib/EnvironmentHandler';
+import { OAuthProvider } from '../../lib/OAuthProvider';
+import {
+  executeFetchUserProfileStrategy,
+  executeFrameHandlerStrategy,
+  executeRedirectStrategy,
+  executeRefreshTokenStrategy,
+  makeProfileInfo,
+} from '../../lib/PassportStrategyHelper';
+import {
+  AuthProviderConfig,
+  EnvironmentProviderConfig,
+  GenericOAuth2ProviderConfig,
+  GenericOAuth2ProviderOptions,
+  OAuthProviderHandlers,
+  OAuthResponse,
+  PassportDoneCallback,
+  RedirectInfo,
+} from '../types';
+
+type PrivateInfo = {
+  refreshToken: string;
+};
+
+export class OAuth2AuthProvider implements OAuthProviderHandlers {
+  private readonly _strategy: OAuth2Strategy;
+
+  constructor(options: GenericOAuth2ProviderOptions) {
+    this._strategy = new OAuth2Strategy(
+      { ...options, passReqToCallback: false as true },
+      (
+        accessToken: any,
+        refreshToken: any,
+        params: any,
+        rawProfile: passport.Profile,
+        done: PassportDoneCallback<OAuthResponse, PrivateInfo>,
+      ) => {
+        const profile = makeProfileInfo(rawProfile, params.id_token);
+        done(
+          undefined,
+          {
+            providerInfo: {
+              idToken: params.id_token,
+              accessToken,
+              scope: params.scope,
+              expiresInSeconds: params.expires_in,
+            },
+            profile,
+          },
+          {
+            refreshToken,
+          },
+        );
+      },
+    );
+  }
+
+  async start(
+    req: express.Request,
+    options: Record<string, string>,
+  ): Promise<RedirectInfo> {
+    const providerOptions = {
+      ...options,
+      accessType: 'offline',
+      prompt: 'consent',
+    };
+    return await executeRedirectStrategy(req, this._strategy, providerOptions);
+  }
+
+  async handler(
+    req: express.Request,
+  ): Promise<{ response: OAuthResponse; refreshToken: string }> {
+    const { response, privateInfo } = await executeFrameHandlerStrategy<
+      OAuthResponse,
+      PrivateInfo
+    >(req, this._strategy);
+
+    return {
+      response: await this.populateIdentity(response),
+      refreshToken: privateInfo.refreshToken,
+    };
+  }
+
+  async refresh(refreshToken: string, scope: string): Promise<OAuthResponse> {
+    const { accessToken, params } = await executeRefreshTokenStrategy(
+      this._strategy,
+      refreshToken,
+      scope,
+    );
+
+    const profile = await executeFetchUserProfileStrategy(
+      this._strategy,
+      accessToken,
+      params.id_token,
+    );
+
+    return this.populateIdentity({
+      providerInfo: {
+        accessToken,
+        idToken: params.id_token,
+        expiresInSeconds: params.expires_in,
+        scope: params.scope,
+      },
+      profile,
+    });
+  }
+
+  // Use this function to grab the user profile info from the token
+  // Then populate the profile with it
+  private async populateIdentity(
+    response: OAuthResponse,
+  ): Promise<OAuthResponse> {
+    const { profile } = response;
+
+    if (!profile.email) {
+      throw new Error('Profile does not contain a profile');
+    }
+
+    const id = profile.email.split('@')[0];
+
+    return { ...response, backstageIdentity: { id } };
+  }
+}
+
+export function createOAuth2Provider(
+  { baseUrl }: AuthProviderConfig,
+  providerConfig: EnvironmentProviderConfig,
+  logger: Logger,
+  tokenIssuer: TokenIssuer,
+) {
+  const envProviders: EnvironmentHandlers = {};
+
+  for (const [env, envConfig] of Object.entries(providerConfig)) {
+    const config = (envConfig as unknown) as GenericOAuth2ProviderConfig;
+    const { secure, appOrigin } = config;
+    const callbackURLParam = `?env=${env}`;
+    const opts = {
+      clientID: config.clientId,
+      clientSecret: config.clientSecret,
+      callbackURL: `${baseUrl}/oauth2/handler/frame${callbackURLParam}`,
+      authorizationURL: config.authorizationURL,
+      tokenURL: config.tokenURL,
+    };
+
+    if (
+      !opts.clientID ||
+      !opts.clientSecret ||
+      !opts.authorizationURL ||
+      !opts.tokenURL
+    ) {
+      if (process.env.NODE_ENV !== 'development') {
+        throw new Error(
+          'Failed to initialize OAuth2 auth provider, set AUTH_OAUTH2_CLIENT_ID, AUTH_OAUTH2_CLIENT_SECRET, AUTH_OAUTH2_AUTH_URL, and AUTH_OAUTH2_TOKEN_URL env vars',
+        );
+      }
+
+      logger.warn(
+        'OAuth2 auth provider disabled, set AUTH_OAUTH2_CLIENT_ID, AUTH_OAUTH2_CLIENT_SECRET, AUTH_OAUTH2_AUTH_URL, and AUTH_OAUTH2_TOKEN_URL env vars to enable',
+      );
+      continue;
+    }
+
+    envProviders[env] = new OAuthProvider(new OAuth2AuthProvider(opts), {
+      disableRefresh: false,
+      providerId: 'oauth2',
+      secure,
+      baseUrl,
+      appOrigin,
+      tokenIssuer,
+    });
+  }
+
+  return new EnvironmentHandler(envProviders);
+}

plugins/auth-backend/src/providers/types.ts

@@ -33,6 +33,11 @@ export type OAuthProviderOptions = {
   callbackURL: string;
 };
 
+export type GenericOAuth2ProviderOptions = OAuthProviderOptions & {
+  authorizationURL: string;
+  tokenURL: string;
+};
+
 export type OAuthProviderConfig = {
   /**
    * Cookies can be marked with a secure flag to send cookies only when the request
@@ -61,6 +66,11 @@ export type OAuthProviderConfig = {
   audience?: string;
 };
 
+export type GenericOAuth2ProviderConfig = OAuthProviderConfig & {
+  authorizationURL: string;
+  tokenURL: string;
+};
+
 export type EnvironmentProviderConfig = {
   /**
    * key, values are environment names and OAuthProviderConfigs

plugins/auth-backend/src/service/router.ts

@@ -100,6 +100,16 @@ export async function createRouter(
             audience: process.env.AUTH_OKTA_AUDIENCE,
           },
         },
+        oauth2: {
+          development: {
+            appOrigin: 'http://localhost:3000',
+            secure: false,
+            clientId: process.env.AUTH_OAUTH2_CLIENT_ID!,
+            clientSecret: process.env.AUTH_OAUTH2_CLIENT_SECRET!,
+            authorizationURL: process.env.AUTH_OAUTH2_AUTH_URL!,
+            tokenURL: process.env.AUTH_OAUTH2_TOKEN_URL!,
+          },
+        },
       },
     },
   };