Validate persisted session info on both save and load

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/wise-melons-hope.md

@@ -0,0 +1,5 @@
+---
+'@backstage/core-app-api': patch
+---
+
+Schema-validate local storage cached session info on load

packages/core-app-api/package.json

@@ -42,7 +42,8 @@
     "prop-types": "^15.7.2",
     "react-router-dom": "6.0.0-beta.0",
     "react-use": "^17.2.4",
-    "zen-observable": "^0.8.15"
+    "zen-observable": "^0.8.15",
+    "zod": "^3.11.6"
   },
   "peerDependencies": {
     "@types/react": "^16.13.1 || ^17.0.0",

packages/core-app-api/src/apis/implementations/auth/github/GithubAuth.ts

@@ -14,25 +14,25 @@
  * limitations under the License.
  */
 
-import { DefaultAuthConnector } from '../../../../lib/AuthConnector';
-import { GithubSession } from './types';
 import {
+  AuthRequestOptions,
+  BackstageIdentity,
   OAuthApi,
+  ProfileInfo,
   SessionApi,
   SessionState,
-  ProfileInfo,
-  BackstageIdentity,
-  AuthRequestOptions,
 } from '@backstage/core-plugin-api';
 import { Observable } from '@backstage/types';
-import { SessionManager } from '../../../../lib/AuthSessionManager/types';
+import { DefaultAuthConnector } from '../../../../lib/AuthConnector';
 import {
   AuthSessionStore,
   RefreshingAuthSessionManager,
   StaticAuthSessionManager,
 } from '../../../../lib/AuthSessionManager';
-import { OAuthApiCreateOptions } from '../types';
 import { OptionalRefreshSessionManagerMux } from '../../../../lib/AuthSessionManager/OptionalRefreshSessionManagerMux';
+import { SessionManager } from '../../../../lib/AuthSessionManager/types';
+import { OAuthApiCreateOptions } from '../types';
+import { GithubSession, githubSessionSchema } from './types';
 
 export type GithubAuthResponse = {
   providerInfo: {
@@ -105,6 +105,7 @@ export default class GithubAuth implements OAuthApi, SessionApi {
         sessionScopes: (session: GithubSession) => session.providerInfo.scopes,
       }),
       storageKey: `${provider.id}Session`,
+      schema: githubSessionSchema,
       sessionScopes: (session: GithubSession) => session.providerInfo.scopes,
     });
 

packages/core-app-api/src/apis/implementations/auth/github/index.ts

@@ -14,5 +14,5 @@
  * limitations under the License.
  */
 
-export * from './types';
+export type { GithubSession } from './types';
 export { default as GithubAuth } from './GithubAuth';

packages/core-app-api/src/apis/implementations/auth/github/types.ts

@@ -15,6 +15,7 @@
  */
 
 import { ProfileInfo, BackstageIdentity } from '@backstage/core-plugin-api';
+import { z } from 'zod';
 
 /**
  * Session information for GitHub auth.
@@ -30,3 +31,25 @@ export type GithubSession = {
   profile: ProfileInfo;
   backstageIdentity: BackstageIdentity;
 };
+
+export const githubSessionSchema: z.ZodSchema<GithubSession> = z.object({
+  providerInfo: z.object({
+    accessToken: z.string(),
+    scopes: z.set(z.string()),
+    expiresAt: z.date().optional(),
+  }),
+  profile: z.object({
+    email: z.string().optional(),
+    displayName: z.string().optional(),
+    picture: z.string().optional(),
+  }),
+  backstageIdentity: z.object({
+    id: z.string(),
+    token: z.string(),
+    identity: z.object({
+      type: z.literal('user'),
+      userEntityRef: z.string(),
+      ownershipEntityRefs: z.array(z.string()),
+    }),
+  }),
+});

packages/core-app-api/src/apis/implementations/auth/saml/SamlAuth.ts

@@ -14,24 +14,24 @@
  * limitations under the License.
  */
 
-import { DirectAuthConnector } from '../../../../lib/AuthConnector';
-import { SessionManager } from '../../../../lib/AuthSessionManager/types';
 import {
-  ProfileInfo,
-  BackstageIdentity,
-  SessionState,
   AuthRequestOptions,
-  ProfileInfoApi,
+  BackstageIdentity,
   BackstageIdentityApi,
+  ProfileInfo,
+  ProfileInfoApi,
   SessionApi,
+  SessionState,
 } from '@backstage/core-plugin-api';
 import { Observable } from '@backstage/types';
-import { SamlSession } from './types';
+import { DirectAuthConnector } from '../../../../lib/AuthConnector';
 import {
   AuthSessionStore,
   StaticAuthSessionManager,
 } from '../../../../lib/AuthSessionManager';
+import { SessionManager } from '../../../../lib/AuthSessionManager/types';
 import { AuthApiCreateOptions } from '../types';
+import { SamlSession, samlSessionSchema } from './types';
 
 export type SamlAuthResponse = {
   profile: ProfileInfo;
@@ -72,6 +72,7 @@ export default class SamlAuth
     const authSessionStore = new AuthSessionStore<SamlSession>({
       manager: sessionManager,
       storageKey: `${provider.id}Session`,
+      schema: samlSessionSchema,
     });
 
     return new SamlAuth(authSessionStore);

packages/core-app-api/src/apis/implementations/auth/saml/types.ts

@@ -13,7 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { ProfileInfo, BackstageIdentity } from '@backstage/core-plugin-api';
+
+import { BackstageIdentity, ProfileInfo } from '@backstage/core-plugin-api';
+import { z } from 'zod';
 
 /**
  * Session information for SAML auth.
@@ -25,3 +27,21 @@ export type SamlSession = {
   profile: ProfileInfo;
   backstageIdentity: BackstageIdentity;
 };
+
+export const samlSessionSchema: z.ZodSchema<SamlSession> = z.object({
+  userId: z.string(),
+  profile: z.object({
+    email: z.string().optional(),
+    displayName: z.string().optional(),
+    picture: z.string().optional(),
+  }),
+  backstageIdentity: z.object({
+    id: z.string(),
+    token: z.string(),
+    identity: z.object({
+      type: z.literal('user'),
+      userEntityRef: z.string(),
+      ownershipEntityRefs: z.array(z.string()),
+    }),
+  }),
+});

packages/core-app-api/src/lib/AuthSessionManager/AuthSessionStore.test.ts

@@ -13,11 +13,15 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+import { withLogCollector } from '@backstage/test-utils';
+import { z } from 'zod';
 import { AuthSessionStore } from './AuthSessionStore';
 import { SessionManager } from './types';
 
 const defaultOptions = {
   storageKey: 'my-key',
+  schema: z.any(),
   sessionScopes: (session: string) => new Set(session.split(' ')),
 };
 
@@ -147,4 +151,48 @@ describe('GheAuth AuthSessionStore', () => {
     store.sessionState$();
     expect(manager.sessionState$).toHaveBeenCalled();
   });
+
+  it('should schema-validate stored data', async () => {
+    const manager = new MockManager();
+
+    const firstStore = new AuthSessionStore<boolean>({
+      manager,
+      storageKey: 'a',
+      schema: z.boolean(),
+      sessionScopes: () => new Set(),
+    });
+    const secondStore = new AuthSessionStore<number>({
+      manager,
+      storageKey: 'a',
+      schema: z.number(),
+      sessionScopes: () => new Set(),
+    });
+
+    firstStore.setSession(true);
+    await expect(firstStore.getSession({})).resolves.toBe(true);
+
+    await expect(
+      withLogCollector(async () => {
+        await expect(secondStore.getSession({})).resolves.toBeUndefined();
+      }),
+    ).resolves.toMatchObject({
+      log: [
+        expect.stringContaining(
+          'Failed to load session from local storage because it did not conform to the expected schema',
+        ),
+      ],
+    });
+
+    await expect(
+      withLogCollector(async () => {
+        await secondStore.setSession('no' as any);
+      }),
+    ).resolves.toMatchObject({
+      warn: [
+        expect.stringContaining(
+          'Failed to save session to local storage because it did not conform to the expected schema',
+        ),
+      ],
+    });
+  });
 });

packages/core-app-api/src/lib/AuthSessionManager/AuthSessionStore.ts

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import { ZodSchema } from 'zod';
 import {
   MutableSessionManager,
   SessionScopesFunc,
@@ -27,6 +28,8 @@ type Options<T> = {
   manager: MutableSessionManager<T>;
   /** Storage key to use to store sessions */
   storageKey: string;
+  /** The schema used to validate the stored data */
+  schema: ZodSchema<T>;
   /** Used to get the scope of the session */
   sessionScopes?: SessionScopesFunc<T>;
   /** Used to check if the session needs to be refreshed, defaults to never refresh */
@@ -42,19 +45,22 @@ type Options<T> = {
 export class AuthSessionStore<T> implements MutableSessionManager<T> {
   private readonly manager: MutableSessionManager<T>;
   private readonly storageKey: string;
+  private readonly schema: ZodSchema<T>;
   private readonly sessionShouldRefreshFunc: SessionShouldRefreshFunc<T>;
   private readonly helper: SessionScopeHelper<T>;
 
   constructor(options: Options<T>) {
     const {
       manager,
       storageKey,
+      schema,
       sessionScopes,
       sessionShouldRefresh = () => false,
     } = options;
 
     this.manager = manager;
     this.storageKey = storageKey;
+    this.schema = schema;
     this.sessionShouldRefreshFunc = sessionShouldRefresh;
     this.helper = new SessionScopeHelper({
       sessionScopes,
@@ -104,7 +110,16 @@ export class AuthSessionStore<T> implements MutableSessionManager<T> {
           }
           return value;
         });
-        return session;
+
+        try {
+          return this.schema.parse(session);
+        } catch (e) {
+          // eslint-disable-next-line no-console
+          console.log(
+            `Failed to load session from local storage because it did not conform to the expected schema, ${e}`,
+          );
+          throw e;
+        }
       }
 
       return undefined;
@@ -117,19 +132,30 @@ export class AuthSessionStore<T> implements MutableSessionManager<T> {
   private saveSession(session: T | undefined) {
     if (session === undefined) {
       localStorage.removeItem(this.storageKey);
-    } else {
-      localStorage.setItem(
-        this.storageKey,
-        JSON.stringify(session, (_key, value) => {
-          if (value instanceof Set) {
-            return {
-              __type: 'Set',
-              __value: Array.from(value),
-            };
-          }
-          return value;
-        }),
+      return;
+    }
+
+    try {
+      this.schema.parse(session);
+    } catch (e) {
+      // eslint-disable-next-line no-console
+      console.warn(
+        `Failed to save session to local storage because it did not conform to the expected schema, ${e}`,
       );
+      return;
     }
+
+    localStorage.setItem(
+      this.storageKey,
+      JSON.stringify(session, (_key, value) => {
+        if (value instanceof Set) {
+          return {
+            __type: 'Set',
+            __value: Array.from(value),
+          };
+        }
+        return value;
+      }),
+    );
   }
 }