Both auth surfaces now fail-closed by default:
- ALLOWED_MCP_CLIENTS: removed the silent `claude-desktop` and
`test-mcp-client` fallbacks. Empty/unset env var leaves the registry
empty so /oauth/authorize rejects every client_id.
- ALLOWED_MGMT_CLIENT (new): comma-separated list of OIDC client_ids
whose tokens are accepted by /api/management/*. Enforced in
verify_token_for_management_api on both the cache-hit and cache-miss
paths against the token's client_id claim. Unset/empty rejects all.
Compose: set ALLOWED_MGMT_CLIENT=nextcloudMcpServerUIPublicClient on
mcp-multi-user-basic so the existing Astrolabe integration test
(test_astrolabe_chunk_context.py) still passes.
env.sample documents both vars and notes they may be consolidated later.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Since both multi-audience and exchange modes now validate the same thing
(MCP audience only per RFC 7519), consolidated the duplicate methods:
- Removed duplicate verification methods (_verify_multi_audience_token
and _verify_mcp_audience_only)
- Created single _verify_mcp_audience() method for all validation
- Removed duplicate helper (_validate_multi_audience), kept _has_mcp_audience
- Mode only affects logging and what happens AFTER verification
The mode distinction is now purely about post-verification behavior:
- Multi-audience mode: Use token directly (Nextcloud validates its own)
- Exchange mode: Exchange for Nextcloud-audience token via RFC 8693
This makes the code cleaner and clearer about what's actually happening -
both modes do identical validation, they just differ in how the validated
token is used.
All tests pass: unit (65), OAuth integration confirmed working.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Per RFC 7519 Section 4.1.3, resource servers should only validate their
own presence in the audience claim, not check for other resource servers.
Changes:
- UnifiedTokenVerifier now validates only MCP audience (not Nextcloud's)
- Nextcloud independently validates its own audience when receiving API calls
- This is NOT token passthrough (we validate tokens before use)
- This IS token reuse which is explicitly allowed by RFC 8707
Updates:
- Simplified _validate_multi_audience() to follow OAuth spec
- Updated docstrings and comments to clarify RFC 7519 compliance
- Fixed unit tests that expected dual-audience validation
- Updated ADR-005 to document the correct OAuth interpretation
- All tests pass: unit (65), smoke (5), OAuth integration
This makes the implementation simpler, more maintainable, and properly
aligned with OAuth 2.0 specifications while maintaining security.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
Replace two non-compliant token verifiers (NextcloudTokenVerifier and
ProgressiveConsentTokenVerifier) with a single UnifiedTokenVerifier that properly
validates token audiences per MCP Security Best Practices specification.
The previous implementation had a critical security vulnerability where tokens
intended for the MCP server were passed directly to Nextcloud APIs without
proper audience validation (token passthrough anti-pattern). This violates
OAuth 2.0 security principles and the MCP specification.
Changes:
- Add UnifiedTokenVerifier supporting two compliant modes:
* Multi-audience mode (default): Validates tokens contain BOTH MCP and
Nextcloud audiences, enabling direct use without exchange
* Token exchange mode (opt-in): Validates MCP audience only, exchanges
for Nextcloud tokens via RFC 8693 with caching to minimize latency
- Remove token passthrough vulnerability from context.py and context_helper.py
- Implement token exchange caching (5-minute TTL default) to reduce network calls
- Add required environment variables for audience validation:
* NEXTCLOUD_MCP_SERVER_URL - MCP server URL (used as audience)
* NEXTCLOUD_RESOURCE_URI - Nextcloud resource identifier
* TOKEN_EXCHANGE_CACHE_TTL - Cache TTL for exchanged tokens
- Update docker-compose.yml with resource URI configuration for both OAuth modes
- Add comprehensive test suite (29 tests) covering both authentication modes
- Remove legacy NextcloudTokenVerifier and ProgressiveConsentTokenVerifier
Security improvements:
- Eliminates token passthrough anti-pattern
- Enforces proper audience separation between MCP and Nextcloud
- Complies with MCP Security Best Practices and RFC 8707/8693
- Maintains performance with token exchange caching
Test results: 65/65 unit tests passed, 5/5 smoke tests passed
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
