fix: harden tenant auth and quality gates

api/src/auth/session-validation.middleware.spec.ts

@@ -1,4 +1,4 @@
-import { UnauthorizedException } from '@nestjs/common';
+import { ForbiddenException, UnauthorizedException } from '@nestjs/common';
 import { SessionValidationMiddleware, type SessionRequest } from './session-validation.middleware';
 
 const record = {
@@ -6,10 +6,10 @@ const record = {
   lastActivityAt: 1, lastAuthenticatedAt: 1, absoluteExpiresAt: Date.now() + 1000,
 };
 
-function request(path = '/api/admin/users', cookie = 'cmpp_admin_session=opaque-token'): SessionRequest {
+function request(path = '/api/admin/users', cookie = 'cmpp_admin_session=opaque-token', tenantId?: string): SessionRequest {
   return {
     originalUrl: path,
-    header: jest.fn((name: string) => name === 'cookie' ? cookie : undefined),
+    header: jest.fn((name: string) => name === 'cookie' ? cookie : name === 'x-tenant-id' ? tenantId : undefined),
   };
 }
 
@@ -17,7 +17,7 @@ describe('SessionValidationMiddleware', () => {
   const cookieName = jest.fn((portal: 'admin' | 'client') => `cmpp_${portal}_session`);
 
   it('accepts an active Redis session and exposes its user and record', async () => {
-    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', status: 'active', deletedAt: null, sessionVersion: 3 }) } };
+    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', tenantId: null, status: 'active', deletedAt: null, sessionVersion: 3 }) } };
     const sessions = { cookieName, validate: jest.fn().mockResolvedValue({ status: 'active', record }), remove: jest.fn() };
     const middleware = new SessionValidationMiddleware(prisma as never, sessions as never);
     const currentRequest = request();
@@ -32,7 +32,7 @@ describe('SessionValidationMiddleware', () => {
   });
 
   it('rejects a session after the user session version changes', async () => {
-    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', status: 'active', deletedAt: null, sessionVersion: 4 }) } };
+    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', tenantId: null, status: 'active', deletedAt: null, sessionVersion: 4 }) } };
     const sessions = { cookieName, validate: jest.fn().mockResolvedValue({ status: 'active', record }), remove: jest.fn() };
     const middleware = new SessionValidationMiddleware(prisma as never, sessions as never);
 
@@ -41,7 +41,7 @@ describe('SessionValidationMiddleware', () => {
   });
 
   it('only lets a locked session reach unlock and logout endpoints', async () => {
-    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', status: 'active', deletedAt: null, sessionVersion: 3 }) } };
+    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', tenantId: null, status: 'active', deletedAt: null, sessionVersion: 3 }) } };
     const sessions = { cookieName, validate: jest.fn().mockResolvedValue({ status: 'locked', record }), remove: jest.fn() };
     const middleware = new SessionValidationMiddleware(prisma as never, sessions as never);
 
@@ -53,7 +53,7 @@ describe('SessionValidationMiddleware', () => {
 
   it('selects only the cookie belonging to the requested portal', async () => {
     const clientRecord = { ...record, portal: 'client' as const };
-    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', status: 'active', deletedAt: null, sessionVersion: 3 }) } };
+    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', tenantId: 'tenant-a', status: 'active', deletedAt: null, sessionVersion: 3 }) } };
     const sessions = { cookieName, validate: jest.fn().mockResolvedValue({ status: 'active', record: clientRecord }), remove: jest.fn() };
     const middleware = new SessionValidationMiddleware(prisma as never, sessions as never);
     const currentRequest = request('/api/client/users', 'cmpp_admin_session=admin-token; cmpp_client_session=client-token');
@@ -62,6 +62,33 @@ describe('SessionValidationMiddleware', () => {
 
     expect(sessions.validate).toHaveBeenCalledWith('client-token', false);
     expect(currentRequest.sessionToken).toBe('client-token');
+    expect(currentRequest.sessionTenantId).toBe('tenant-a');
+  });
+
+  it('rejects a client session whose user is not bound to a tenant', async () => {
+    const clientRecord = { ...record, portal: 'client' as const };
+    const prisma = { user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', tenantId: null, status: 'active', deletedAt: null, sessionVersion: 3 }) } };
+    const sessions = { cookieName, validate: jest.fn().mockResolvedValue({ status: 'active', record: clientRecord }), remove: jest.fn() };
+    const middleware = new SessionValidationMiddleware(prisma as never, sessions as never);
+
+    await expect(middleware.use(request('/api/client/users', 'cmpp_client_session=client-token'), {}, jest.fn()))
+      .rejects.toBeInstanceOf(ForbiddenException);
+  });
+
+  it('rejects and audits a client tenant header that disagrees with the authenticated user', async () => {
+    const clientRecord = { ...record, portal: 'client' as const };
+    const prisma = {
+      user: { findUnique: jest.fn().mockResolvedValue({ id: 'user-1', tenantId: 'tenant-a', status: 'active', deletedAt: null, sessionVersion: 3 }) },
+      operationLog: { create: jest.fn().mockResolvedValue({ id: 'log-1' }) },
+    };
+    const sessions = { cookieName, validate: jest.fn().mockResolvedValue({ status: 'active', record: clientRecord }), remove: jest.fn() };
+    const middleware = new SessionValidationMiddleware(prisma as never, sessions as never);
+
+    await expect(middleware.use(request('/api/client/users', 'cmpp_client_session=client-token', 'tenant-b'), {}, jest.fn()))
+      .rejects.toMatchObject({ response: expect.objectContaining({ code: 'CLIENT_TENANT_MISMATCH' }) });
+    expect(prisma.operationLog.create).toHaveBeenCalledWith({
+      data: expect.objectContaining({ tenantId: 'tenant-a', userId: 'user-1', action: 'security.client_tenant_mismatch' }),
+    });
   });
 
   it('does not accept an admin cookie for a client route', async () => {