feat: add verification for v2 auth (#3155)

Author: Salazareo

src/backend/core/http/expressAugmentation.ts

@@ -35,40 +35,18 @@ declare global {
     // eslint-disable-next-line @typescript-eslint/no-namespace
     namespace Express {
         interface Request {
-            /**
-             * Populated by the global auth probe when a valid token is
-             * attached to the request (Bearer header, auth_token body/query,
-             * session cookie, or socket handshake). Absent for anonymous
-             * requests — route-level gates decide whether to reject.
-             */
             actor?: Actor;
 
             /** The raw token string, if one was presented and parsed. */
             token?: string;
 
-            /**
-             * Set by the global auth probe when a token was extracted from
-             * the request but failed to resolve to an actor (bad signature,
-             * expired, references a deleted session/user/app, or has a
-             * legacy shape v2 can't authenticate). Lets `requireAuthGate`
-             * distinguish "no token" from "token present but invalid" and
-             * emit the legacy `token_auth_failed` error so old clients
-             * trigger their re-login flow.
-             */
             tokenAuthFailed?: boolean;
 
-            /**
-             * Raw request body bytes, captured by the global JSON parser's
-             * `verify` callback. Available for any JSON request — needed by
-             * webhook handlers that verify an HMAC over the exact bytes the
-             * sender signed (e.g., AppStore prod webhooks, BroadcastService
-             * inter-instance hooks).
-             *
-             * Set only when the global JSON parser actually ran (request had
-             * `Content-Type: application/json` or one of the recognized
-             * JSON-as-text variants). For non-JSON requests it stays
-             * `undefined`.
-             */
+            requiresReauth?: {
+                reason: 'token_v1' | 'session_revoked' | 'session_expired';
+                auth_id?: string;
+            };
+
             rawBody?: Buffer;
 
             /** Parsed user-agent, populated by the global UA-parsing middleware. */

src/backend/core/http/middleware/authProbe.test.ts

@@ -34,27 +34,48 @@ import { createAuthProbe } from './authProbe';
 // test wants. This is mocking at a real boundary (a service), which the
 // AGENTS.md guidance explicitly allows.
 
+type AuthResultLike =
+    | { actor: Actor }
+    | { reauth: { reason: string; auth_id?: string } }
+    | { invalid: true };
+
 interface StubAuth {
     service: AuthService;
     seenTokens: string[];
-    /** What the next call to authenticateFromToken should return. */
+    /** Legacy setter — accepts the old Actor|null|'throw' shape. */
     setNext: (next: Actor | null | 'throw') => void;
+    /** AUTH-4: set the full AuthResult to be returned by `authenticate()`. */
+    setNextResult: (next: AuthResultLike | 'throw') => void;
 }
 
 const makeStubAuth = (defaultActor: Actor | null = null): StubAuth => {
     const seenTokens: string[] = [];
-    let nextResult: Actor | null | 'throw' = defaultActor;
+    let nextResult: AuthResultLike | 'throw' = defaultActor
+        ? { actor: defaultActor }
+        : { invalid: true };
     const service = {
-        authenticateFromToken: async (token: string) => {
+        // AUTH-4 entry point used by the probe.
+        authenticate: async (token: string) => {
             seenTokens.push(token);
             if (nextResult === 'throw') throw new Error('verify failed');
             return nextResult;
         },
+        // Back-compat wrapper for callers that still want Actor | null.
+        authenticateFromToken: async (token: string) => {
+            seenTokens.push(token);
+            if (nextResult === 'throw') throw new Error('verify failed');
+            return 'actor' in nextResult ? nextResult.actor : null;
+        },
     } as unknown as AuthService;
     return {
         service,
         seenTokens,
         setNext: (n) => {
+            if (n === 'throw') nextResult = 'throw';
+            else if (n === null) nextResult = { invalid: true };
+            else nextResult = { actor: n };
+        },
+        setNextResult: (n) => {
             nextResult = n;
         },
     };
@@ -522,6 +543,224 @@ describe('createAuthProbe — actor attachment + failure tracking', () => {
     });
 });
 
+// ── AUTH-4: reauth signal + KV counters ─────────────────────────────
+
+describe('createAuthProbe — AUTH-4 reauth signal', () => {
+    /** Capture KV increments without a real store. */
+    const makeKvStub = () => {
+        const calls: Array<{
+            key: string;
+            pathAndAmountMap: Record<string, number>;
+        }> = [];
+        return {
+            calls,
+            store: {
+                incr: async (args: {
+                    key: string;
+                    pathAndAmountMap: Record<string, number>;
+                }) => {
+                    calls.push(args);
+                    return { res: {} as Record<string, number>, usage: 0 };
+                },
+            },
+        };
+    };
+
+    it('sets requiresReauth and counts v1 + reauth.token_v1 for a legacy v1 token', async () => {
+        const stub = makeStubAuth();
+        stub.setNextResult({
+            reauth: { reason: 'token_v1', auth_id: 'u-legacy' },
+            // Some legacy paths resolve an actor anyway (lazy-backfill).
+            // The probe must still set requiresReauth; gate emits 401.
+            actor: { user: { uuid: 'u-legacy' } },
+        } as never);
+        const kv = makeKvStub();
+        const probe = createAuthProbe({
+            authService: stub.service,
+            kvStore: kv.store,
+        });
+        const { req } = await runProbe(
+            probe,
+            makeReq({ headers: { authorization: 'Bearer v1-tok' } }),
+        );
+        expect(req.requiresReauth).toEqual({
+            reason: 'token_v1',
+            auth_id: 'u-legacy',
+        });
+        // Both increments fire under the same day-bucketed key.
+        expect(kv.calls).toHaveLength(1);
+        expect(kv.calls[0].key).toMatch(/^auth-v2:metrics:\d{4}-\d{2}-\d{2}$/);
+        expect(kv.calls[0].pathAndAmountMap).toEqual({
+            v1: 1,
+            'reauth.token_v1': 1,
+        });
+    });
+
+    it('sets requiresReauth and counts reauth.session_revoked', async () => {
+        const stub = makeStubAuth();
+        stub.setNextResult({
+            reauth: { reason: 'session_revoked', auth_id: 'u-1' },
+        });
+        const kv = makeKvStub();
+        const probe = createAuthProbe({
+            authService: stub.service,
+            kvStore: kv.store,
+        });
+        const { req } = await runProbe(
+            probe,
+            makeReq({ headers: { authorization: 'Bearer tok' } }),
+        );
+        expect(req.requiresReauth?.reason).toBe('session_revoked');
+        expect(kv.calls[0].pathAndAmountMap).toEqual({
+            v1: 1,
+            'reauth.session_revoked': 1,
+        });
+    });
+
+    it('sets requiresReauth and counts reauth.session_expired', async () => {
+        const stub = makeStubAuth();
+        stub.setNextResult({
+            reauth: { reason: 'session_expired', auth_id: 'u-1' },
+        });
+        const kv = makeKvStub();
+        const probe = createAuthProbe({
+            authService: stub.service,
+            kvStore: kv.store,
+        });
+        const { req } = await runProbe(
+            probe,
+            makeReq({ headers: { authorization: 'Bearer tok' } }),
+        );
+        expect(req.requiresReauth?.reason).toBe('session_expired');
+        expect(kv.calls[0].pathAndAmountMap).toEqual({
+            v1: 1,
+            'reauth.session_expired': 1,
+        });
+    });
+
+    it('counts v2 verify (no reauth) for a healthy token', async () => {
+        const stub = makeStubAuth({ user: { uuid: 'u-1' } });
+        const kv = makeKvStub();
+        const probe = createAuthProbe({
+            authService: stub.service,
+            kvStore: kv.store,
+        });
+        const { req } = await runProbe(
+            probe,
+            makeReq({ headers: { authorization: 'Bearer good-tok' } }),
+        );
+        expect(req.actor).toBeTruthy();
+        expect(req.requiresReauth).toBeUndefined();
+        expect(kv.calls[0].pathAndAmountMap).toEqual({ v2: 1 });
+    });
+
+    it('does not increment counters when no token is presented', async () => {
+        const stub = makeStubAuth();
+        const kv = makeKvStub();
+        const probe = createAuthProbe({
+            authService: stub.service,
+            kvStore: kv.store,
+        });
+        await runProbe(probe, makeReq({}));
+        // Anonymous-OK routes pay no metrics cost.
+        expect(kv.calls).toHaveLength(0);
+    });
+
+    it('absorbs KV failures — never rejects on the hot path', async () => {
+        const stub = makeStubAuth({ user: { uuid: 'u-1' } });
+        // Failing KV: increments throw. Probe must still succeed.
+        const failingKv = {
+            incr: async () => {
+                throw new Error('kv unavailable');
+            },
+        };
+        const probe = createAuthProbe({
+            authService: stub.service,
+            kvStore: failingKv,
+        });
+        const { req, next } = await runProbe(
+            probe,
+            makeReq({ headers: { authorization: 'Bearer good-tok' } }),
+        );
+        expect(next).toHaveBeenCalledWith();
+        expect(req.actor).toBeTruthy();
+    });
+
+    it('works without a kvStore (counters become no-ops)', async () => {
+        const stub = makeStubAuth({ user: { uuid: 'u-1' } });
+        // Production may not always pass a KV — fresh installs without
+        // dynamo wired still need a functioning probe.
+        const probe = createAuthProbe({ authService: stub.service });
+        const { req } = await runProbe(
+            probe,
+            makeReq({ headers: { authorization: 'Bearer good-tok' } }),
+        );
+        expect(req.actor).toBeTruthy();
+        expect(req.requiresReauth).toBeUndefined();
+    });
+
+    it('logs `[auth-v2] reauth reason=<r> auth_id=<id>` per event', async () => {
+        // The log line is the human-facing forensic counterpart to the
+        // KV counter. Asserting the exact shape so ops can `grep
+        // '\[auth-v2\] reauth'` and trust the format won't drift.
+        const stub = makeStubAuth();
+        stub.setNextResult({
+            reauth: { reason: 'session_revoked', auth_id: 'u-grep' },
+        });
+        const infoSpy = vi.spyOn(console, 'info').mockImplementation(() => {});
+        try {
+            const probe = createAuthProbe({ authService: stub.service });
+            await runProbe(
+                probe,
+                makeReq({ headers: { authorization: 'Bearer tok' } }),
+            );
+            expect(infoSpy).toHaveBeenCalledWith(
+                '[auth-v2] reauth reason=session_revoked auth_id=u-grep',
+            );
+        } finally {
+            infoSpy.mockRestore();
+        }
+    });
+
+    it('logs `auth_id=-` when the reauth result has no auth_id', async () => {
+        const stub = makeStubAuth();
+        stub.setNextResult({
+            reauth: { reason: 'session_expired' },
+        });
+        const infoSpy = vi.spyOn(console, 'info').mockImplementation(() => {});
+        try {
+            const probe = createAuthProbe({ authService: stub.service });
+            await runProbe(
+                probe,
+                makeReq({ headers: { authorization: 'Bearer tok' } }),
+            );
+            expect(infoSpy).toHaveBeenCalledWith(
+                '[auth-v2] reauth reason=session_expired auth_id=-',
+            );
+        } finally {
+            infoSpy.mockRestore();
+        }
+    });
+
+    it('does not emit a reauth log line on a healthy v2 verify', async () => {
+        const stub = makeStubAuth({ user: { uuid: 'u-1' } });
+        const infoSpy = vi.spyOn(console, 'info').mockImplementation(() => {});
+        try {
+            const probe = createAuthProbe({ authService: stub.service });
+            await runProbe(
+                probe,
+                makeReq({ headers: { authorization: 'Bearer good-tok' } }),
+            );
+            const reauthCalls = infoSpy.mock.calls.filter((args) =>
+                String(args[0]).startsWith('[auth-v2] reauth'),
+            );
+            expect(reauthCalls).toHaveLength(0);
+        } finally {
+            infoSpy.mockRestore();
+        }
+    });
+});
+
 // ── Server-backed end-to-end (real AuthService + DB) ────────────────
 //
 // The unit tests above cover the extraction logic in isolation. This