Files
nextcloud-mcp-server/tests/manual/test_nextcloud_impersonate.py
T
Chris Coutinho e331544cee feat: Implement RFC 8693 token exchange for Keycloak (ADR-002 Tier 2)
Implements OAuth 2.0 Token Exchange (RFC 8693) enabling the MCP server to
exchange service account tokens for user-scoped tokens. This provides an
alternative to refresh tokens for background operations.

**Core Implementation:**
- Added `get_service_account_token()` method to KeycloakOAuthClient for
  client_credentials grant
- Added `exchange_token_for_user()` method implementing RFC 8693 token exchange
- Fixed Fernet encryption key handling in RefreshTokenStorage (was incorrectly
  base64 decoding already-encoded keys)
- Updated OAuth configuration to support offline_access scope and refresh token
  storage infrastructure

**Keycloak Configuration:**
- Enabled `serviceAccountsEnabled` in realm-export.json
- Added `token.exchange.grant.enabled` attribute
- Added `client.token.exchange.standard.enabled` attribute (required for
  Keycloak 26.2+ Standard Token Exchange V2)
- Fresh Keycloak imports now correctly enable token exchange

**Docker Compose:**
- Added TOKEN_ENCRYPTION_KEY and ENABLE_OFFLINE_ACCESS environment variables
- Created oauth-tokens volume for refresh token storage
- Configured both mcp-oauth and mcp-keycloak services

**Testing & Documentation:**
- Added tests/manual/test_token_exchange.py - Validates complete RFC 8693 flow
- Added tests/manual/test_nextcloud_impersonate.py - Documents session-based
  impersonation limitations
- Added docs/oauth-impersonation-findings.md - Comprehensive investigation
  findings and resolution documentation

**Verified Working:**
 Service account token acquisition (client_credentials grant)
 RFC 8693 token exchange for internal-to-internal tokens
 Exchanged tokens validate with Nextcloud APIs
 Keycloak 26.4.2 Standard Token Exchange V2 support

**Known Limitations:**
- User impersonation (requested_subject) requires Keycloak Legacy V1 with
  preview features
- Cross-client token exchange limited to same realm
- Refresh token storage infrastructure ready but unused (MCP protocol limitation)

Dependencies: aiosqlite>=0.20.0

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-02 22:03:19 +01:00

228 lines
7.5 KiB
Python

"""
Manual test for Nextcloud impersonate API.
This script tests using the Nextcloud impersonate app to allow
admin users to act on behalf of other users.
This is NOT the same as OAuth token exchange, but could serve
as a workaround for background operations.
Usage:
# Start app container
docker compose up -d app
# Run the test
uv run python tests/manual/test_nextcloud_impersonate.py
"""
import asyncio
import logging
import os
import sys
# Add parent directory to path
sys.path.insert(0, os.path.join(os.path.dirname(__file__), "../.."))
import httpx
# Setup logging
logging.basicConfig(
level=logging.INFO, format="%(levelname)-8s | %(name)-30s | %(message)s"
)
logger = logging.getLogger(__name__)
async def main():
"""Test Nextcloud impersonate API"""
# Configuration
nextcloud_host = os.getenv("NEXTCLOUD_HOST", "http://localhost:8080")
admin_user = os.getenv("NEXTCLOUD_USERNAME", "admin")
admin_password = os.getenv("NEXTCLOUD_PASSWORD", "admin")
target_user = "testuser" # We'll create this user
logger.info("=" * 80)
logger.info("Nextcloud Impersonate API Test")
logger.info("=" * 80)
logger.info(f"Nextcloud: {nextcloud_host}")
logger.info(f"Admin user: {admin_user}")
logger.info(f"Target user: {target_user}")
logger.info("")
async with httpx.AsyncClient() as client:
# Step 1: Login as admin and get session
logger.info("Step 1: Logging in as admin...")
login_response = await client.post(
f"{nextcloud_host}/login",
data={
"user": admin_user,
"password": admin_password,
},
follow_redirects=True,
)
if login_response.status_code != 200:
logger.error(f"❌ Admin login failed: {login_response.status_code}")
return 1
# Get requesttoken from response
requesttoken = None
for cookie in client.cookies.jar:
if cookie.name == "nc_session":
logger.info(f"✓ Admin logged in, session: {cookie.value[:20]}...")
break
logger.info("")
# Step 2: Create test user if doesn't exist
logger.info(f"Step 2: Creating test user '{target_user}'...")
create_user_response = await client.post(
f"{nextcloud_host}/ocs/v1.php/cloud/users",
auth=(admin_user, admin_password),
data={
"userid": target_user,
"password": "testpassword123",
},
headers={"OCS-APIRequest": "true"},
)
if create_user_response.status_code in (200, 400): # 400 if already exists
logger.info("✓ Test user ready")
else:
logger.warning(
f"User creation response: {create_user_response.status_code}"
)
# Make sure user has logged in at least once (requirement for impersonation)
logger.info(f" Performing initial login for {target_user}...")
await client.post(
f"{nextcloud_host}/login",
data={
"user": target_user,
"password": "testpassword123",
},
follow_redirects=True,
)
logger.info("✓ Test user has logged in")
# Re-login as admin
await client.post(
f"{nextcloud_host}/login",
data={
"user": admin_user,
"password": admin_password,
},
follow_redirects=True,
)
logger.info("")
# Step 3: Get CSRF token for impersonate request
logger.info("Step 3: Getting CSRF token...")
# Try to get token from settings page
settings_response = await client.get(
f"{nextcloud_host}/settings/users",
follow_redirects=True,
)
# Extract requesttoken from HTML
import re
token_match = re.search(r'data-requesttoken="([^"]+)"', settings_response.text)
if token_match:
requesttoken = token_match.group(1)
logger.info(f"✓ CSRF token acquired: {requesttoken[:20]}...")
else:
logger.error("❌ Could not extract CSRF token from page")
return 1
logger.info("")
# Step 4: Call impersonate API
logger.info(f"Step 4: Impersonating user '{target_user}'...")
impersonate_response = await client.post(
f"{nextcloud_host}/apps/impersonate/user",
data={
"userId": target_user,
},
headers={
"requesttoken": requesttoken,
"Content-Type": "application/x-www-form-urlencoded",
},
)
if impersonate_response.status_code != 200:
logger.error(f"❌ Impersonate failed: {impersonate_response.status_code}")
logger.error(f"Response: {impersonate_response.text}")
return 1
logger.info("✓ Impersonation successful")
logger.info("")
# Step 5: Test API call as impersonated user
logger.info("Step 5: Testing API call as impersonated user...")
capabilities_response = await client.get(
f"{nextcloud_host}/ocs/v2.php/cloud/capabilities",
headers={"OCS-APIRequest": "true"},
)
if capabilities_response.status_code == 200:
caps = capabilities_response.json()
logger.info(f"✓ API call successful as {target_user}")
logger.info(
f" Version: {caps.get('ocs', {}).get('data', {}).get('version', {}).get('string')}"
)
else:
logger.error(f"❌ API call failed: {capabilities_response.status_code}")
return 1
logger.info("")
# Step 6: Get current user to verify impersonation
logger.info("Step 6: Verifying current user...")
user_response = await client.get(
f"{nextcloud_host}/ocs/v2.php/cloud/user",
headers={"OCS-APIRequest": "true"},
)
if user_response.status_code == 200:
user_data = user_response.json()
current_user = user_data.get("ocs", {}).get("data", {}).get("id")
logger.info(f"✓ Current user: {current_user}")
if current_user == target_user:
logger.info(" ✓ Successfully impersonating target user!")
else:
logger.warning(f" ⚠ Expected {target_user}, got {current_user}")
else:
logger.error(f"❌ User check failed: {user_response.status_code}")
logger.info("")
logger.info("=" * 80)
logger.info("✅ Impersonate API Test PASSED")
logger.info("=" * 80)
logger.info("")
logger.info("Summary:")
logger.info(" 1. Admin can impersonate other users via session-based API")
logger.info(" 2. Impersonated session can access APIs as that user")
logger.info(" 3. Requires admin credentials and CSRF token")
logger.info("")
logger.info("Limitations:")
logger.info(" - Session-based (not stateless like OAuth)")
logger.info(" - Requires admin credentials")
logger.info(" - Target user must have logged in at least once")
logger.info(" - Not suitable for distributed/background workers")
logger.info("")
logger.info("For background operations, consider:")
logger.info(" - Use service account with appropriate permissions")
logger.info(" - Or implement proper OAuth delegation (RFC 8693)")
logger.info("")
return 0
if __name__ == "__main__":
exit_code = asyncio.run(main())
sys.exit(exit_code)