fix(security): share-login must not bypass gallery password (GHSA-9hmx-68vc-qpqw)

POST /auth/gallery/share-login validated only the 128-bit share token and then
minted a full type:'gallery' access token regardless of require_password —
computing requiresPassword at the end only to echo it, never enforce it. Anyone
holding a gallery's share link could read and download every photo in a
password-protected gallery via a direct API call, no password needed.

Fix: compute requiresPassword before minting; for a password-protected gallery
return { requires_password: true } with NO token and NO cookie. The client then
goes through /gallery/verify, which does bcrypt.compare the password. The public
(no-password) auto-login path is unchanged. The frontend already falls through
to the password prompt when share-login returns no token/event.

Adds route regression test covering the bypass, the public path, and bad tokens.

backend/__tests__/routes/authShareLoginPassword.test.js

@@ -0,0 +1,127 @@
+/**
+ * Regression test for GHSA-9hmx-68vc-qpqw — share-link login must not bypass
+ * the gallery password.
+ *
+ * POST /auth/gallery/share-login validates only the share token. For a
+ * password-protected gallery it previously minted a full `type:'gallery'`
+ * access token on the share token alone, letting anyone holding the share URL
+ * read the gallery without the password. The fix: when the gallery requires a
+ * password, return `{ requires_password: true }` with NO token and NO cookie.
+ */
+
+const express = require('express');
+const request = require('supertest');
+
+process.env.JWT_SECRET = 'share-login-test-secret';
+
+const events = [];
+
+jest.mock('../../src/database/db', () => {
+  function dbFn(table) {
+    if (table === 'events') {
+      let filter = () => true;
+      return {
+        where(criteria) {
+          filter = (row) => Object.entries(criteria).every(([k, v]) => {
+            if (k === 'is_active') return Boolean(row.is_active) === Boolean(v);
+            if (k === 'is_archived') return Boolean(row.is_archived) === Boolean(v);
+            return row[k] === v;
+          });
+          return this;
+        },
+        async first() { return events.find(filter); },
+      };
+    }
+    return { where() { return this; }, async first() { return undefined; } };
+  }
+  dbFn.raw = async () => {};
+  return { db: dbFn, logActivity: async () => {} };
+});
+
+// Share token is stored plainly on the fake event row.
+jest.mock('../../src/services/shareLinkService', () => ({
+  getEventShareToken: (event) => event.share_token,
+  resolveShareIdentifier: async () => ({ event: null }),
+}));
+
+const mockSetGalleryAuthCookies = jest.fn();
+jest.mock('../../src/utils/tokenUtils', () => ({
+  setGalleryAuthCookies: (...args) => mockSetGalleryAuthCookies(...args),
+  clearGalleryAuthCookies: jest.fn(),
+  getGalleryTokenFromRequest: jest.fn(),
+  setAdminAuthCookies: jest.fn(),
+}));
+
+jest.mock('../../src/utils/authSecurity', () => ({
+  trackFailedAttempt: jest.fn(async () => {}),
+  trackSuccessfulLogin: jest.fn(async () => {}),
+  checkAccountLockout: jest.fn(async () => ({ isLocked: false })),
+  resetLockout: jest.fn(async () => {}),
+}));
+
+// Collaborators the router imports at load but the share-login path doesn't hit.
+jest.mock('../../src/services/recaptcha', () => ({ verifyRecaptcha: async () => true }));
+jest.mock('../../src/services/mfaService', () => ({}));
+jest.mock('../../src/middleware/sessionTimeout', () => ({ endSession: jest.fn(), sessionTimeoutMiddleware: (req, res, next) => next() }));
+jest.mock('../../src/utils/tokenRevocation', () => ({ revokeToken: jest.fn(async () => {}), isTokenRevoked: async () => false }));
+
+const authRouter = require('../../src/routes/auth');
+
+function makeApp() {
+  const app = express();
+  app.use(express.json());
+  app.use('/auth', authRouter);
+  return app;
+}
+
+const SHARE_TOKEN = 'a'.repeat(64);
+
+beforeEach(() => {
+  events.length = 0;
+  mockSetGalleryAuthCookies.mockClear();
+});
+
+describe('POST /auth/gallery/share-login password enforcement', () => {
+  it('does NOT mint a token for a password-protected gallery', async () => {
+    events.push({
+      id: 1, slug: 'private-gallery', is_active: 1, is_archived: 0,
+      require_password: 1, share_token: SHARE_TOKEN, event_name: 'Private',
+    });
+    const res = await request(makeApp())
+      .post('/auth/gallery/share-login')
+      .send({ slug: 'private-gallery', token: SHARE_TOKEN });
+
+    expect(res.status).toBe(200);
+    expect(res.body.requires_password).toBe(true);
+    expect(res.body.token).toBeUndefined();
+    expect(mockSetGalleryAuthCookies).not.toHaveBeenCalled();
+  });
+
+  it('mints a token for a public (no-password) gallery', async () => {
+    events.push({
+      id: 2, slug: 'public-gallery', is_active: 1, is_archived: 0,
+      require_password: false, share_token: SHARE_TOKEN, event_name: 'Public',
+    });
+    const res = await request(makeApp())
+      .post('/auth/gallery/share-login')
+      .send({ slug: 'public-gallery', token: SHARE_TOKEN });
+
+    expect(res.status).toBe(200);
+    expect(typeof res.body.token).toBe('string');
+    expect(res.body.event).toBeDefined();
+    expect(mockSetGalleryAuthCookies).toHaveBeenCalledTimes(1);
+  });
+
+  it('rejects a wrong share token regardless of password setting', async () => {
+    events.push({
+      id: 3, slug: 'public-gallery', is_active: 1, is_archived: 0,
+      require_password: false, share_token: SHARE_TOKEN, event_name: 'Public',
+    });
+    const res = await request(makeApp())
+      .post('/auth/gallery/share-login')
+      .send({ slug: 'public-gallery', token: 'b'.repeat(64) });
+
+    expect(res.status).toBe(401);
+    expect(mockSetGalleryAuthCookies).not.toHaveBeenCalled();
+  });
+});

backend/src/routes/auth.js

@@ -543,6 +543,18 @@ router.post('/gallery/share-login', [
       return res.status(401).json({ error: 'Invalid or expired share link' });
     }
 
+    const requiresPassword = !(event.require_password === false || event.require_password === 0 || event.require_password === '0');
+
+    // The share link only proves the holder was given the link — it is NOT the
+    // gallery password. For a password-protected gallery, minting a full
+    // `type:'gallery'` token here would let anyone with the share URL bypass
+    // the password entirely (GHSA-9hmx-68vc-qpqw). Signal that a password is
+    // still required and return WITHOUT a token/cookie; the client then goes
+    // through POST /gallery/verify, which does check the password.
+    if (requiresPassword) {
+      return res.json({ requires_password: true });
+    }
+
     const jwtToken = jwt.sign({
       eventId: event.id,
       eventSlug: event.slug,
@@ -557,8 +569,6 @@ router.post('/gallery/share-login', [
     await trackSuccessfulLogin(`gallery:${event.slug}:share`, ipAddress, userAgent);
     setGalleryAuthCookies(res, jwtToken, event.slug);
 
-    const requiresPassword = !(event.require_password === false || event.require_password === 0 || event.require_password === '0');
-
     res.json({
       token: jwtToken,
       event: {