Add security hardening and additional auth tests

Security improvements:
- Add password strength validation (min 8 characters)
- Invalidate all sessions on password change/reset
- Add timing-safe user lookup to prevent enumeration attacks
- Fix SQLAlchemy boolean comparisons (== True -> is_(True))
- Change default admin password to 'changeme123' (meets min length)

New tests (7 additional):
- Inactive user login attempt blocked
- Short password rejected on create/change/reset
- Duplicate username rejected (409)
- Non-owner API key deletion blocked (403)
- Sessions invalidated on password change

backend/tests/integration/test_auth_api.py

@@ -12,7 +12,7 @@ class TestAuthLogin:
         """Test successful login with default admin credentials."""
         response = integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
         assert response.status_code == 200
         data = response.json()
@@ -49,7 +49,7 @@ class TestAuthLogout:
         # First login
         login_response = integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
         assert login_response.status_code == 200
 
@@ -75,7 +75,7 @@ class TestAuthMe:
         # Login first
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         response = integration_client.get("/api/v1/auth/me")
@@ -106,13 +106,13 @@ class TestAuthChangePassword:
         # Login first
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         # Change password
         response = integration_client.post(
             "/api/v1/auth/change-password",
-            json={"current_password": "admin", "new_password": "newpassword123"},
+            json={"current_password": "changeme123", "new_password": "newpassword123"},
         )
         assert response.status_code == 200
 
@@ -120,7 +120,7 @@ class TestAuthChangePassword:
         integration_client.cookies.clear()
         response = integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
         assert response.status_code == 401
 
@@ -132,10 +132,11 @@ class TestAuthChangePassword:
         assert response.status_code == 200
 
         # Reset password back to original for other tests
-        integration_client.post(
+        reset_response = integration_client.post(
             "/api/v1/auth/change-password",
-            json={"current_password": "newpassword123", "new_password": "admin"},
+            json={"current_password": "newpassword123", "new_password": "changeme123"},
         )
+        assert reset_response.status_code == 200, "Failed to reset admin password back to default"
 
     @pytest.mark.integration
     def test_change_password_wrong_current(self, integration_client):
@@ -143,7 +144,7 @@ class TestAuthChangePassword:
         # Login first
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         response = integration_client.post(
@@ -163,7 +164,7 @@ class TestAPIKeys:
         # Login first
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         # Create API key
@@ -195,7 +196,7 @@ class TestAPIKeys:
         # Login and create API key
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
         create_response = integration_client.post(
             "/api/v1/auth/keys",
@@ -216,7 +217,7 @@ class TestAPIKeys:
         # Clean up
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
         integration_client.delete(f"/api/v1/auth/keys/{key_id}")
 
@@ -226,7 +227,7 @@ class TestAPIKeys:
         # Login and create API key
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
         create_response = integration_client.post(
             "/api/v1/auth/keys",
@@ -257,7 +258,7 @@ class TestAdminUserManagement:
         # Login as admin
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         response = integration_client.get("/api/v1/admin/users")
@@ -272,7 +273,7 @@ class TestAdminUserManagement:
         # Login as admin
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         # Create new user
@@ -305,7 +306,7 @@ class TestAdminUserManagement:
         # Login as admin
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         # Create a test user
@@ -331,7 +332,7 @@ class TestAdminUserManagement:
         # Login as admin
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
 
         # Create a test user
@@ -362,7 +363,7 @@ class TestAdminUserManagement:
         # Login as admin and create non-admin user
         integration_client.post(
             "/api/v1/auth/login",
-            json={"username": "admin", "password": "admin"},
+            json={"username": "admin", "password": "changeme123"},
         )
         test_username = f"nonadmin_{uuid4().hex[:8]}"
         integration_client.post(
@@ -381,3 +382,379 @@ class TestAdminUserManagement:
         response = integration_client.get("/api/v1/admin/users")
         assert response.status_code == 403
         assert "Admin privileges required" in response.json()["detail"]
+
+
+class TestSecurityEdgeCases:
+    """Tests for security edge cases and validation."""
+
+    @pytest.mark.integration
+    def test_login_inactive_user(self, integration_client):
+        """Test that inactive users cannot login."""
+        # Login as admin and create a user
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        test_username = f"inactive_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Deactivate the user
+        integration_client.put(
+            f"/api/v1/admin/users/{test_username}",
+            json={"is_active": False},
+        )
+
+        # Try to login as inactive user
+        integration_client.cookies.clear()
+        response = integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": test_username, "password": "password123"},
+        )
+        assert response.status_code == 401
+        assert "Invalid username or password" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_password_too_short_on_create(self, integration_client):
+        """Test that short passwords are rejected when creating users."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        response = integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": f"shortpw_{uuid4().hex[:8]}", "password": "short"},
+        )
+        assert response.status_code == 400
+        assert "at least 8 characters" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_password_too_short_on_change(self, integration_client):
+        """Test that short passwords are rejected when changing password."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        response = integration_client.post(
+            "/api/v1/auth/change-password",
+            json={"current_password": "changeme123", "new_password": "short"},
+        )
+        assert response.status_code == 400
+        assert "at least 8 characters" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_password_too_short_on_reset(self, integration_client):
+        """Test that short passwords are rejected when resetting password."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        # Create a test user first
+        test_username = f"resetshort_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        response = integration_client.post(
+            f"/api/v1/admin/users/{test_username}/reset-password",
+            json={"new_password": "short"},
+        )
+        assert response.status_code == 400
+        assert "at least 8 characters" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_duplicate_username_rejected(self, integration_client):
+        """Test that duplicate usernames are rejected."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        test_username = f"duplicate_{uuid4().hex[:8]}"
+        # Create user first time
+        response1 = integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+        assert response1.status_code == 200
+
+        # Try to create same username again
+        response2 = integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password456"},
+        )
+        assert response2.status_code == 409
+        assert "already exists" in response2.json()["detail"]
+
+    @pytest.mark.integration
+    def test_cannot_delete_other_users_api_key(self, integration_client):
+        """Test that users cannot delete API keys owned by other users."""
+        # Login as admin and create an API key
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        create_response = integration_client.post(
+            "/api/v1/auth/keys",
+            json={"name": "admin-key"},
+        )
+        admin_key_id = create_response.json()["id"]
+
+        # Create a non-admin user
+        test_username = f"nonadmin_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Login as non-admin
+        integration_client.cookies.clear()
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Try to delete admin's API key
+        response = integration_client.delete(f"/api/v1/auth/keys/{admin_key_id}")
+        assert response.status_code == 403
+        assert "Cannot delete another user's API key" in response.json()["detail"]
+
+        # Cleanup: login as admin and delete the key
+        integration_client.cookies.clear()
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        integration_client.delete(f"/api/v1/auth/keys/{admin_key_id}")
+
+    @pytest.mark.integration
+    def test_sessions_invalidated_on_password_change(self, integration_client):
+        """Test that all sessions are invalidated when password is changed."""
+        # Create a test user
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        test_username = f"sessiontest_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Login as test user
+        integration_client.cookies.clear()
+        login_response = integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": test_username, "password": "password123"},
+        )
+        assert login_response.status_code == 200
+
+        # Verify session works
+        me_response = integration_client.get("/api/v1/auth/me")
+        assert me_response.status_code == 200
+
+        # Change password
+        integration_client.post(
+            "/api/v1/auth/change-password",
+            json={"current_password": "password123", "new_password": "newpassword123"},
+        )
+
+        # Old session should be invalidated - try to access /me
+        # (note: the change-password call itself may have cleared the session cookie)
+        me_response2 = integration_client.get("/api/v1/auth/me")
+        # This should fail because all sessions were invalidated
+        assert me_response2.status_code == 401
+
+
+class TestSecurityEdgeCases:
+    """Tests for security edge cases and validation."""
+
+    @pytest.mark.integration
+    def test_login_inactive_user(self, integration_client):
+        """Test that inactive users cannot login."""
+        # Login as admin and create a user
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        test_username = f"inactive_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Deactivate the user
+        integration_client.put(
+            f"/api/v1/admin/users/{test_username}",
+            json={"is_active": False},
+        )
+
+        # Try to login as inactive user
+        integration_client.cookies.clear()
+        response = integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": test_username, "password": "password123"},
+        )
+        assert response.status_code == 401
+        assert "Invalid username or password" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_password_too_short_on_create(self, integration_client):
+        """Test that short passwords are rejected when creating users."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        response = integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": f"shortpw_{uuid4().hex[:8]}", "password": "short"},
+        )
+        assert response.status_code == 400
+        assert "at least 8 characters" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_password_too_short_on_change(self, integration_client):
+        """Test that short passwords are rejected when changing password."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        response = integration_client.post(
+            "/api/v1/auth/change-password",
+            json={"current_password": "changeme123", "new_password": "short"},
+        )
+        assert response.status_code == 400
+        assert "at least 8 characters" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_password_too_short_on_reset(self, integration_client):
+        """Test that short passwords are rejected when resetting password."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        # Create a test user first
+        test_username = f"resetshort_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        response = integration_client.post(
+            f"/api/v1/admin/users/{test_username}/reset-password",
+            json={"new_password": "short"},
+        )
+        assert response.status_code == 400
+        assert "at least 8 characters" in response.json()["detail"]
+
+    @pytest.mark.integration
+    def test_duplicate_username_rejected(self, integration_client):
+        """Test that duplicate usernames are rejected."""
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+
+        test_username = f"duplicate_{uuid4().hex[:8]}"
+        # Create user first time
+        response1 = integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+        assert response1.status_code == 200
+
+        # Try to create same username again
+        response2 = integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password456"},
+        )
+        assert response2.status_code == 409
+        assert "already exists" in response2.json()["detail"]
+
+    @pytest.mark.integration
+    def test_cannot_delete_other_users_api_key(self, integration_client):
+        """Test that users cannot delete API keys owned by other users."""
+        # Login as admin and create an API key
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        create_response = integration_client.post(
+            "/api/v1/auth/keys",
+            json={"name": "admin-key"},
+        )
+        admin_key_id = create_response.json()["id"]
+
+        # Create a non-admin user
+        test_username = f"nonadmin_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Login as non-admin
+        integration_client.cookies.clear()
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Try to delete admin's API key
+        response = integration_client.delete(f"/api/v1/auth/keys/{admin_key_id}")
+        assert response.status_code == 403
+        assert "Cannot delete another user's API key" in response.json()["detail"]
+
+        # Cleanup: login as admin and delete the key
+        integration_client.cookies.clear()
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        integration_client.delete(f"/api/v1/auth/keys/{admin_key_id}")
+
+    @pytest.mark.integration
+    def test_sessions_invalidated_on_password_change(self, integration_client):
+        """Test that all sessions are invalidated when password is changed."""
+        # Create a test user
+        integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": "admin", "password": "changeme123"},
+        )
+        test_username = f"sessiontest_{uuid4().hex[:8]}"
+        integration_client.post(
+            "/api/v1/admin/users",
+            json={"username": test_username, "password": "password123"},
+        )
+
+        # Login as test user
+        integration_client.cookies.clear()
+        login_response = integration_client.post(
+            "/api/v1/auth/login",
+            json={"username": test_username, "password": "password123"},
+        )
+        assert login_response.status_code == 200
+
+        # Verify session works
+        me_response = integration_client.get("/api/v1/auth/me")
+        assert me_response.status_code == 200
+
+        # Change password
+        integration_client.post(
+            "/api/v1/auth/change-password",
+            json={"current_password": "password123", "new_password": "newpassword123"},
+        )
+
+        # Old session should be invalidated - try to access /me
+        # (note: the change-password call itself may have cleared the session cookie)
+        me_response2 = integration_client.get("/api/v1/auth/me")
+        # This should fail because all sessions were invalidated
+        assert me_response2.status_code == 401