feat: multi-issuer OIDC support with config consolidation

- Support multiple OAuth providers (core-api, tatlock-ui, tatlock)
- Changed oidc_issuer (string) to oidc_issuers (list)
- Per-issuer JWKS caching
- Validates token issuer against allowed list
- Consolidated config files (removed deprecated src/config.py, src/security.py)
- Updated imports to use src/shared/config and src/shared/security

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/auth/oidc.py

@@ -22,29 +22,42 @@ class OIDCConfig:
     def __init__(self):
         # These will be set from environment variables in config.py
         self.enabled = False
-        self.issuer = ""
+        self.issuers: list[str] = []
         self.audiences: list[str] = []
-        self.jwks_uri = ""
 
-    def configure(self, enabled: bool, issuer: str, audiences: list[str]):
+    def configure(self, enabled: bool, issuers: list[str], audiences: list[str]):
         """Configure OIDC settings"""
         self.enabled = enabled
-        self.issuer = issuer
+        self.issuers = [iss.rstrip('/') for iss in issuers]  # Normalize without trailing slash
         self.audiences = audiences
-        self.jwks_uri = f"{issuer.rstrip('/')}/jwks/"
-        logger.info(f"OIDC configured: enabled={enabled}, issuer={issuer}, audiences={audiences}")
+        logger.info(f"OIDC configured: enabled={enabled}, issuers={self.issuers}, audiences={audiences}")
+
+    def get_jwks_uri(self, issuer: str) -> str:
+        """Get JWKS URI for a specific issuer"""
+        return f"{issuer.rstrip('/')}/jwks/"
+
+    def is_valid_issuer(self, issuer: str) -> bool:
+        """Check if issuer is in the allowed list"""
+        normalized = issuer.rstrip('/')
+        return normalized in self.issuers
 
 
 # Global OIDC config instance
 oidc_config = OIDCConfig()
 
 
-@lru_cache(maxsize=1)
-def get_jwks() -> Dict:
-    """
-    Fetch JSON Web Key Set (JWKS) from Authentik
+# Per-issuer JWKS cache
+_jwks_cache: Dict[str, Dict] = {}
 
-    Cached to avoid repeated requests. Cache is cleared on server restart.
+
+def get_jwks_for_issuer(issuer: str) -> Dict:
+    """
+    Fetch JSON Web Key Set (JWKS) for a specific issuer.
+
+    Cached per-issuer to avoid repeated requests. Cache is cleared on server restart.
+
+    Args:
+        issuer: The token issuer URL
 
     Returns:
         JWKS dictionary containing public keys for token verification
@@ -55,15 +68,24 @@ def get_jwks() -> Dict:
     if not oidc_config.enabled:
         return {}
 
+    normalized_issuer = issuer.rstrip('/')
+
+    # Return cached JWKS if available
+    if normalized_issuer in _jwks_cache:
+        return _jwks_cache[normalized_issuer]
+
+    jwks_uri = oidc_config.get_jwks_uri(normalized_issuer)
+
     try:
-        logger.debug(f"Fetching JWKS from {oidc_config.jwks_uri}")
-        response = httpx.get(oidc_config.jwks_uri, timeout=10.0)
+        logger.debug(f"Fetching JWKS from {jwks_uri}")
+        response = httpx.get(jwks_uri, timeout=10.0)
         response.raise_for_status()
         jwks = response.json()
-        logger.info(f"JWKS fetched successfully ({len(jwks.get('keys', []))} keys)")
+        logger.info(f"JWKS fetched successfully for {normalized_issuer} ({len(jwks.get('keys', []))} keys)")
+        _jwks_cache[normalized_issuer] = jwks
         return jwks
     except Exception as e:
-        logger.error(f"Failed to fetch JWKS: {e}")
+        logger.error(f"Failed to fetch JWKS from {jwks_uri}: {e}")
         raise HTTPException(
             status_code=503,
             detail="Authentication service unavailable"
@@ -109,6 +131,15 @@ async def get_current_user(
     token = credentials.credentials
 
     try:
+        # First, extract issuer from unverified claims to know which JWKS to use
+        unverified_claims = jwt.get_unverified_claims(token)
+        token_issuer = unverified_claims.get("iss", "")
+
+        # Validate issuer is in our allowed list
+        if not oidc_config.is_valid_issuer(token_issuer):
+            logger.warning(f"Invalid token issuer: {token_issuer}")
+            raise HTTPException(status_code=401, detail="Invalid token issuer")
+
         # Decode token header to get key ID
         unverified_header = jwt.get_unverified_header(token)
         kid = unverified_header.get("kid")
@@ -116,8 +147,8 @@ async def get_current_user(
         if not kid:
             raise HTTPException(status_code=401, detail="Invalid token format")
 
-        # Find matching key in JWKS
-        jwks = get_jwks()
+        # Find matching key in JWKS for this specific issuer
+        jwks = get_jwks_for_issuer(token_issuer)
         rsa_key = None
 
         for key in jwks.get("keys", []):
@@ -130,12 +161,13 @@ async def get_current_user(
             raise HTTPException(status_code=401, detail="Invalid token key")
 
         # Verify and decode token (accepts any of the configured audiences)
+        # Use the token's issuer for validation (already verified it's in our allowed list)
         payload = jwt.decode(
             token,
             rsa_key,
             algorithms=["RS256"],
             audience=oidc_config.audiences,
-            issuer=oidc_config.issuer,
+            issuer=token_issuer,
         )
 
         user_email = payload.get("email", "unknown")

src/auth/service.py

@@ -13,7 +13,7 @@ from sqlalchemy import select
 from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload
 
-from src.config import get_settings
+from src.shared.config import get_settings
 from src.logging_config import get_logger
 from src.db.models import User, Role, UserPreferences, Group
 from src.auth.schemas import TokenInfoSchema, UserSchema, RoleSchema, UserPreferencesSchema, UserListItemSchema, BulkSyncResultSchema, GroupListItemSchema