Make grantToken tenant-aware (#4475)

Adds multi-tenancy support on grantToken endpoint by pulling tenant ID from refresh token. Changes include: - Make refresh token minting / validating stateless by serializing RefreshTokenRecord instead of representing with random string - Changing server side logic to check request body's refresh token for tenant ID (note that `grantToken` is the only endpoint in which the tenant ID cannot be obtained from the request path, query params, or ID token in the request body) - Added additional unit tests for `grantToken` edge cases Fixes #4414.
firebase · Apr 27, 2022 · 58a95e0 · 58a95e0
1 parent 28b3467
commit 58a95e0
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1 +1,2 @@
 - Updates `superstatic` to `v8` to fix audit issues.
+- Make grantToken tenant-aware (#4475)
diff --git a/src/emulator/auth/operations.ts b/src/emulator/auth/operations.ts
@@ -1704,7 +1704,6 @@ function grantToken(
   assert(reqBody.refreshToken, "MISSING_REFRESH_TOKEN");
 
   const refreshTokenRecord = state.validateRefreshToken(reqBody.refreshToken);
-  assert(refreshTokenRecord, "INVALID_REFRESH_TOKEN");
   assert(!refreshTokenRecord.user.disabled, "USER_DISABLED");
   const tokens = issueTokens(state, refreshTokenRecord.user, refreshTokenRecord.provider, {
     extraClaims: refreshTokenRecord.extraClaims,

diff --git a/src/emulator/auth/server.ts b/src/emulator/auth/server.ts
@@ -7,7 +7,7 @@ import { OpenAPIObject, PathsObject, ServerObject, OperationObject } from "opena
 import { EmulatorLogger } from "../emulatorLogger";
 import { Emulators } from "../types";
 import { authOperations, AuthOps, AuthOperation, FirebaseJwtPayload } from "./operations";
-import { AgentProjectState, ProjectState } from "./state";
+import { AgentProjectState, decodeRefreshToken, ProjectState } from "./state";
 import apiSpecUntyped from "./apiSpec";
 import {
   PromiseController,
@@ -506,6 +506,19 @@ function toExegesisController(
         targetTenantId = targetTenantId || decoded?.payload.firebase.tenant;
       }
 
+      // Need to check refresh token for tenant ID for grantToken endpoint
+      if (ctx.requestBody?.refreshToken) {
+        const refreshTokenRecord = decodeRefreshToken(ctx.requestBody!.refreshToken);
+        if (refreshTokenRecord.tenantId && targetTenantId) {
+          // Shouldn't ever reach this assertion, but adding for completeness
+          assert(
+            refreshTokenRecord.tenantId === targetTenantId,
+            "TENANT_ID_MISMATCH: ((Refresh token tenant ID does not match target tenant ID.))"
+          );
+        }
+        targetTenantId = targetTenantId || refreshTokenRecord.tenantId;
+      }
+
       return operation(getProjectStateById(targetProjectId, targetTenantId), ctx.requestBody, ctx);
     };
   }

diff --git a/src/emulator/auth/state.ts b/src/emulator/auth/state.ts
@@ -9,7 +9,7 @@ import {
 } from "./utils";
 import { MakeRequired } from "./utils";
 import { AuthCloudFunction } from "./cloudFunctions";
-import { assert } from "./errors";
+import { assert, BadRequestError } from "./errors";
 import { MfaEnrollments, Schemas } from "./types";
 
 export const PROVIDER_PASSWORD = "password";
@@ -27,8 +27,6 @@ export abstract class ProjectState {
   private localIdForPhoneNumber: Map<string, string> = new Map();
   private localIdsForProviderEmail: Map<string, Set<string>> = new Map();
   private userIdForProviderRawId: Map<string, Map<string, string>> = new Map();
-  private refreshTokens: Map<string, RefreshTokenRecord> = new Map();
-  private refreshTokensForLocalId: Map<string, Set<string>> = new Map();
   private oobs: Map<string, OobRecord> = new Map();
   private verificationCodes: Map<string, PhoneVerificationRecord> = new Map();
   private temporaryProofs: Map<string, TemporaryProofRecord> = new Map();
@@ -123,15 +121,6 @@ export abstract class ProjectState {
   deleteUser(user: UserInfo): void {
     this.users.delete(user.localId);
     this.removeUserFromIndex(user);
-
-    const refreshTokens = this.refreshTokensForLocalId.get(user.localId);
-    if (refreshTokens) {
-      this.refreshTokensForLocalId.delete(user.localId);
-      for (const refreshToken of refreshTokens) {
-        this.refreshTokens.delete(refreshToken);
-      }
-    }
-
     this.authCloudFunction.dispatch("delete", user);
   }
 
@@ -399,34 +388,30 @@ export abstract class ProjectState {
     } = {}
   ): string {
     const localId = userInfo.localId;
-    const refreshToken = randomBase64UrlStr(204);
-    this.refreshTokens.set(refreshToken, {
+    const refreshTokenRecord = {
+      _AuthEmulatorRefreshToken: "DO NOT MODIFY",
       localId,
       provider,
       extraClaims,
+      projectId: this.projectId,
       secondFactor,
       tenantId: userInfo.tenantId,
-    });
-    let refreshTokens = this.refreshTokensForLocalId.get(localId);
-    if (!refreshTokens) {
-      refreshTokens = new Set();
-      this.refreshTokensForLocalId.set(localId, refreshTokens);
-    }
-    refreshTokens.add(refreshToken);
+    };
+    const refreshToken = encodeRefreshToken(refreshTokenRecord);
     return refreshToken;
   }
 
-  validateRefreshToken(refreshToken: string):
-    | {
-        user: UserInfo;
-        provider: string;
-        extraClaims: Record<string, unknown>;
-        secondFactor?: SecondFactorRecord;
-      }
-    | undefined {
-    const record = this.refreshTokens.get(refreshToken);
-    if (!record) {
-      return undefined;
+  validateRefreshToken(refreshToken: string): {
+    user: UserInfo;
+    provider: string;
+    extraClaims: Record<string, unknown>;
+    secondFactor?: SecondFactorRecord;
+  } {
+    const record = decodeRefreshToken(refreshToken);
+    assert(record.projectId === this.projectId, "INVALID_REFRESH_TOKEN");
+    if (this instanceof TenantProjectState) {
+      // Shouldn't ever reach this assertion, but adding for completeness
+      assert(record.tenantId === this.tenantId, "TENANT_ID_MISMATCH");
     }
     return {
       user: this.getUserByLocalIdAssertingExists(record.localId),
@@ -495,8 +480,6 @@ export abstract class ProjectState {
     this.localIdForPhoneNumber.clear();
     this.localIdsForProviderEmail.clear();
     this.userIdForProviderRawId.clear();
-    this.refreshTokens.clear();
-    this.refreshTokensForLocalId.clear();
 
     // We do not clear OOBs / phone verification codes since some of those may
     // still be valid (e.g. email link / phone sign-in may still create a new
@@ -871,10 +854,12 @@ export type Config = {
   blockingFunctions: BlockingFunctionsConfig;
 };
 
-interface RefreshTokenRecord {
+export interface RefreshTokenRecord {
+  _AuthEmulatorRefreshToken: string;
   localId: string;
   provider: string;
   extraClaims: Record<string, unknown>;
+  projectId: string;
   secondFactor?: SecondFactorRecord;
   tenantId?: string;
 }
@@ -922,6 +907,22 @@ interface TemporaryProofRecord {
   // a bit easier. Therefore, there's no need to record createdAt timestamps.
 }
 
+export function encodeRefreshToken(refreshTokenRecord: RefreshTokenRecord): string {
+  return Buffer.from(JSON.stringify(refreshTokenRecord), "utf8").toString("base64");
+}
+
+export function decodeRefreshToken(refreshTokenString: string): RefreshTokenRecord {
+  let refreshTokenRecord: RefreshTokenRecord;
+  try {
+    const json = Buffer.from(refreshTokenString, "base64").toString("utf8");
+    refreshTokenRecord = JSON.parse(json) as RefreshTokenRecord;
+  } catch {
+    throw new BadRequestError("INVALID_REFRESH_TOKEN");
+  }
+  assert(refreshTokenRecord._AuthEmulatorRefreshToken, "INVALID_REFRESH_TOKEN");
+  return refreshTokenRecord;
+}
+
 function getProviderEmailsForUser(user: UserInfo): Set<string> {
   const emails = new Set<string>();
   user.providerUserInfo?.forEach(({ email }) => {

diff --git a/src/test/emulators/auth/misc.spec.ts b/src/test/emulators/auth/misc.spec.ts
@@ -1,6 +1,11 @@
 import { expect } from "chai";
 import { decode as decodeJwt, JwtHeader } from "jsonwebtoken";
-import { UserInfo } from "../../../emulator/auth/state";
+import {
+  decodeRefreshToken,
+  encodeRefreshToken,
+  RefreshTokenRecord,
+  UserInfo,
+} from "../../../emulator/auth/state";
 import {
   deleteAccount,
   getAccountInfoByIdToken,
@@ -47,6 +52,40 @@ describeAuthEmulator("token refresh", ({ authApi, getClock }) => {
       });
   });
 
+  it("should exchange refresh tokens for new tokens in a tenant project", async () => {
+    const tenant = await registerTenant(authApi(), PROJECT_ID, {
+      disableAuth: false,
+      allowPasswordSignup: true,
+    });
+    const { refreshToken, localId } = await registerUser(authApi(), {
+      email: "alice@example.com",
+      password: "notasecret",
+      tenantId: tenant.tenantId,
+    });
+
+    await authApi()
+      .post("/securetoken.googleapis.com/v1/token")
+      .type("form")
+      // snake_case parameters also work, per OAuth 2.0 spec.
+      .send({ refresh_token: refreshToken, grantType: "refresh_token" })
+      .query({ key: "fake-api-key" })
+      .then((res) => {
+        expectStatusCode(200, res);
+        expect(res.body.id_token).to.be.a("string");
+        expect(res.body.access_token).to.equal(res.body.id_token);
+        expect(res.body.refresh_token).to.be.a("string");
+        expect(res.body.expires_in)
+          .to.be.a("string")
+          .matches(/[0-9]+/);
+        expect(res.body.project_id).to.equal("12345");
+        expect(res.body.token_type).to.equal("Bearer");
+        expect(res.body.user_id).to.equal(localId);
+
+        const refreshTokenRecord = decodeRefreshToken(res.body.refresh_token);
+        expect(refreshTokenRecord.tenantId).to.equal(tenant.tenantId);
+      });
+  });
+
   it("should populate auth_time to match lastLoginAt (in seconds since epoch)", async () => {
     getClock().tick(444); // Make timestamps a bit more interesting (non-zero).
     const emailUser = { email: "alice@example.com", password: "notasecret" };
@@ -75,6 +114,62 @@ describeAuthEmulator("token refresh", ({ authApi, getClock }) => {
     expect(decoded!.payload.auth_time).to.equal(lastLoginAtSeconds);
   });
 
+  it("should error if grant type is missing", async () => {
+    const { refreshToken } = await registerAnonUser(authApi());
+
+    await authApi()
+      .post("/securetoken.googleapis.com/v1/token")
+      .type("form")
+      // snake_case parameters also work, per OAuth 2.0 spec.
+      .send({ refresh_token: refreshToken })
+      .query({ key: "fake-api-key" })
+      .then((res) => {
+        expectStatusCode(400, res);
+        expect(res.body.error.message).to.contain("MISSING_GRANT_TYPE");
+      });
+  });
+
+  it("should error if grant type is not refresh_token", async () => {
+    const { refreshToken } = await registerAnonUser(authApi());
+
+    await authApi()
+      .post("/securetoken.googleapis.com/v1/token")
+      .type("form")
+      // snake_case parameters also work, per OAuth 2.0 spec.
+      .send({ refresh_token: refreshToken, grantType: "other_grant_type" })
+      .query({ key: "fake-api-key" })
+      .then((res) => {
+        expectStatusCode(400, res);
+        expect(res.body.error.message).to.contain("INVALID_GRANT_TYPE");
+      });
+  });
+
+  it("should error if refresh token is missing", async () => {
+    await authApi()
+      .post("/securetoken.googleapis.com/v1/token")
+      .type("form")
+      // snake_case parameters also work, per OAuth 2.0 spec.
+      .send({ grantType: "refresh_token" })
+      .query({ key: "fake-api-key" })
+      .then((res) => {
+        expectStatusCode(400, res);
+        expect(res.body.error.message).to.contain("MISSING_REFRESH_TOKEN");
+      });
+  });
+
+  it("should error on malformed refresh tokens", async () => {
+    await authApi()
+      .post("/securetoken.googleapis.com/v1/token")
+      .type("form")
+      // snake_case parameters also work, per OAuth 2.0 spec.
+      .send({ refresh_token: "malformedToken", grantType: "refresh_token" })
+      .query({ key: "fake-api-key" })
+      .then((res) => {
+        expectStatusCode(400, res);
+        expect(res.body.error.message).to.contain("INVALID_REFRESH_TOKEN");
+      });
+  });
+
   it("should error if user is disabled", async () => {
     const { refreshToken, localId } = await registerAnonUser(authApi());
     await updateAccountByLocalId(authApi(), localId, { disableUser: true });
@@ -107,6 +202,47 @@ describeAuthEmulator("token refresh", ({ authApi, getClock }) => {
           .equals("UNSUPPORTED_PASSTHROUGH_OPERATION");
       });
   });
+
+  it("should error when refresh tokens are from a different project", async () => {
+    const refreshTokenRecord = {
+      _AuthEmulatorRefreshToken: "DO NOT MODIFY",
+      localId: "localId",
+      provider: "provider",
+      extraClaims: {},
+      projectId: "notMatchingProjectId",
+    };
+    const refreshToken = encodeRefreshToken(refreshTokenRecord);
+
+    await authApi()
+      .post("/securetoken.googleapis.com/v1/token")
+      .type("form")
+      .send({ refresh_token: refreshToken, grantType: "refresh_token" })
+      .query({ key: "fake-api-key" })
+      .then((res) => {
+        expectStatusCode(400, res);
+        expect(res.body.error).to.have.property("message").equals("INVALID_REFRESH_TOKEN");
+      });
+  });
+
+  it("should error on refresh tokens without required fields", async () => {
+    const refreshTokenRecord = {
+      localId: "localId",
+      provider: "provider",
+      extraClaims: {},
+      projectId: "notMatchingProjectId",
+    };
+    const refreshToken = encodeRefreshToken(refreshTokenRecord as RefreshTokenRecord);
+
+    await authApi()
+      .post("/securetoken.googleapis.com/v1/token")
+      .type("form")
+      .send({ refresh_token: refreshToken, grantType: "refresh_token" })
+      .query({ key: "fake-api-key" })
+      .then((res) => {
+        expectStatusCode(400, res);
+        expect(res.body.error).to.have.property("message").equals("INVALID_REFRESH_TOKEN");
+      });
+  });
 });
 
 describeAuthEmulator("createSessionCookie", ({ authApi }) => {

diff --git a/src/test/emulators/auth/rest.spec.ts b/src/test/emulators/auth/rest.spec.ts
@@ -180,7 +180,7 @@ describeAuthEmulator("authentication", ({ authApi }) => {
       });
   });
 
-  it("should deny requests where tenant IDs do not match in the token and path", async () => {
+  it("should deny requests where tenant IDs do not match in the ID token and path", async () => {
     const tenant = await registerTenant(authApi(), PROJECT_ID, {
       disableAuth: false,
       allowPasswordSignup: true,
@@ -203,12 +203,12 @@ describeAuthEmulator("authentication", ({ authApi }) => {
       });
   });
 
-  it("should deny requests where tenant IDs do not match in the token and request body", async () => {
+  it("should deny requests where tenant IDs do not match in the ID token and request body", async () => {
     const tenant = await registerTenant(authApi(), PROJECT_ID, {
       disableAuth: false,
       allowPasswordSignup: true,
     });
-    const { idToken, localId } = await registerUser(authApi(), {
+    const { idToken } = await registerUser(authApi(), {
       email: "alice@example.com",
       password: "notasecret",
       tenantId: tenant.tenantId,