Commit Graph
3 Commits
Author SHA1 Message Date
Chris CoutinhoandClaude 849c67c32a fix: Complete Keycloak external IdP integration with all tests passing
This commit completes the Keycloak external IdP integration for the MCP
server, implementing ADR-002 Tier 2 (External Identity Provider) with
full Bearer token authentication support.

Key Changes:
1. **Keycloak backchannel-dynamic configuration**
   - Added --hostname-strict=false and --hostname-backchannel-dynamic=true
   - Allows external issuer (localhost:8888) with internal endpoints (keycloak:8080)
   - Solves Docker networking issue where containers can't reach localhost

2. **CORSMiddleware Bearer token patch**
   - Created app-hooks/patches/cors-bearer-token.patch from upstream commit 8fb5e77db82
   - Allows Bearer tokens to bypass CORS/CSRF checks (stateless authentication)
   - Applied via post-installation hook 20-apply-cors-bearer-token-patch.sh
   - Enables app-specific APIs (Notes, Calendar, etc.) to work with Bearer tokens

3. **Patch organization**
   - Moved patches to app-hooks/patches/ directory
   - Updated docker-compose.yml to mount entire app-hooks directory
   - Consolidated patch management for better maintainability

4. **Test improvements**
   - All 11 Keycloak integration tests passing
   - Tests validate OAuth token acquisition, MCP connectivity, token validation,
     tool execution, token persistence, user provisioning, scope filtering,
     and error handling

Architecture:
- Keycloak acts as external OAuth/OIDC identity provider
- MCP server uses Keycloak tokens to access Nextcloud APIs
- Nextcloud user_oidc app validates Bearer tokens from Keycloak
- No admin credentials needed - all API access uses user's OAuth tokens

Cache Note:
- Discovery and JWKS caches must be cleared when switching Keycloak configurations
- Use: docker compose exec redis redis-cli DEL "<cache-key>"
- Or: docker compose exec app php occ user_oidc:provider keycloak --clientid nextcloud

Related:
- ADR-002: Vector sync background jobs authentication
- Validates external IdP integration pattern
- Demonstrates offline_access with refresh tokens (Tier 1 & 2)

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Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-02 22:03:20 +01:00
Chris CoutinhoandClaude 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

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Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-02 22:03:19 +01:00
Chris CoutinhoandClaude f34366a260 feat: Add Keycloak OAuth provider support with refresh token storage
Implements Keycloak as an external OIDC provider following ADR-002
architecture for background job authentication using offline_access.

## Features

- Keycloak OAuth provider with PKCE and offline_access support
- Refresh token storage with Fernet encryption
- Token verifier for both JWT and opaque tokens
- Multi-client validation (realm-level trust)
- Sample configuration for Keycloak integration

## Implementation

### OAuth Provider (keycloak_oauth.py)
- Authorization Code Flow with PKCE
- Refresh token exchange
- OIDC discovery endpoint support
- Token validation with JWKS

### Token Storage (refresh_token_storage.py)
- Encrypted storage using Fernet symmetric encryption
- SQLite backend for persistence
- Token rotation support
- Per-user token management

### Token Verifier Updates
- Support both JWT (self-encoded) and opaque tokens
- JWKS-based JWT signature verification
- Introspection endpoint fallback for opaque tokens
- Scope extraction from both token types

### Configuration
- .env.keycloak.sample: Example configuration with Keycloak URLs
- docs/keycloak-multi-client-validation.md: Realm-level validation documentation
- app-hooks/post-installation/10-install-user_oidc-app.sh: Updated dependencies

## Architecture Notes

- MCP Server is a protected resource (requires OAuth)
- MCP Client initiates OAuth flow and shares refresh tokens
- Refresh tokens enable background operations without admin credentials
- Supports future token exchange delegation when Keycloak implements it

## References

- ADR-002: Vector Database Background Sync Authentication
- RFC 6749: OAuth 2.0 (offline_access, refresh tokens)
- RFC 7517: JSON Web Key (JWK)

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

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