fix(auth_v2): require scim:write auth on all SCIM routes

The SCIM router mounted /scim/v2/* with no security dependency, so any caller
could create or delete users and groups unauthenticated. Guard the whole router
with Security(get_current_principal, scopes=["scim:write"]) per design 03 §11, so
provisioning callers authenticate with the same bearer token or API key as every
other route and the scope gates them: unauthenticated requests now 401, an
authenticated principal without scim:write gets 403 insufficient_scope.

Also document two deployment facts uncovered alongside this: uvicorn's
--proxy-headers rewrites request.client from X-Forwarded-For before this module's
trusted_proxy_cidrs check runs and silently bypasses it (install_auth docstring),
and the scheme_order precedence where HTTP precedes openIdConnect so a bearer JWT
is labeled bearer_jwt rather than oidc (both verify identically).

litellm/auth_v2/config.py

@@ -84,6 +84,10 @@ class SamlConfig(BaseModel):
 
 
 class AuthConfig(BaseModel):
+    # First-match-wins precedence. HTTP precedes OPENID_CONNECT, so a bearer JWT
+    # is claimed by HttpAuthenticator (auth_method=bearer_jwt) and OidcAuthenticator
+    # never runs; both share the same JwtVerifiers and verify identically, so this
+    # only changes the auth_method label. Reorder if openIdConnect labeling matters.
     scheme_order: List[SecuritySchemeType] = Field(
         default_factory=lambda: [
             SecuritySchemeType.API_KEY,

litellm/auth_v2/scim.py

@@ -2,7 +2,7 @@ from __future__ import annotations
 
 from typing import Any, Dict, Optional, Type, TypeVar
 
-from fastapi import APIRouter, Request, Response, status
+from fastapi import APIRouter, Request, Response, Security, status
 from fastapi.responses import JSONResponse
 from pydantic import ValidationError
 from scim2_models import (
@@ -23,6 +23,7 @@ from scim2_models import (
 )
 
 from .resolver import ProvisioningStore
+from .security import get_current_principal
 
 R = TypeVar("R", bound=Resource)
 
@@ -63,7 +64,11 @@ def _dump(resource: Resource, ctx: Context) -> Dict[str, Any]:
 
 
 def build_scim_router() -> APIRouter:
-    router = APIRouter(prefix="/scim/v2", tags=["scim"])
+    router = APIRouter(
+        prefix="/scim/v2",
+        tags=["scim"],
+        dependencies=[Security(get_current_principal, scopes=["scim:write"])],
+    )
 
     @router.post("/Users", status_code=status.HTTP_201_CREATED)
     async def create_user(request: Request) -> Response:

litellm/auth_v2/security.py

@@ -31,6 +31,15 @@ def install_auth(
     mount_oidc: bool = True,
     mount_saml: bool = True,
 ) -> AuthContext:
+    """Wire the authenticators, resolver and optional routers onto the app.
+
+    Deployment requirement for trusted-proxy IP resolution: uvicorn's
+    ``--proxy-headers`` (enabled by default) overwrites ``request.client`` from
+    ``X-Forwarded-For`` before this module's ``trusted_proxy_cidrs`` check runs,
+    which silently bypasses it. Run uvicorn with ``--no-proxy-headers`` and let
+    this module resolve the client IP, or leave ``trusted_proxy_cidrs`` empty and
+    rely on uvicorn's own ``--forwarded-allow-ips``. Do not enable both.
+    """
     ctx = AuthContext(config, build_authenticators(config), resolver)
     app.state.auth_v2 = ctx
     if mount_scim: