headroom/tests/test_provider_registry_extended.py
Tejas Chopra 3e3c409436
fix(security): validate caller-supplied upstreams on every resolution path (#3195)
## Summary

CVE-2026-77775 (SSRF via `x-headroom-base-url`) is **not fully fixed on
current `main`**. The advisory lists 0.36.1 as the last affected
version; one route still forwards to any destination a caller names.

`upstream_guard.is_safe_upstream_url` was added and wired into
`/v1/messages` and the catch-all passthrough. But
`select_passthrough_base_url` moved from `providers/proxy_routes.py` to
`providers/proxy_targets.py`, and the guard did not follow it. Its Azure
branch returns the header verbatim whenever an `api-key` header is
present — **both values are caller-supplied** — and `POST
/v1/alpha/search` resolves its upstream through that helper without
checking the header itself.

## Verified, not inferred

Against the current tree, with a listener on loopback standing in for an
internal service:

```
proxy status                : 200
internal service hit        : 1 time(s)
Authorization it received   : 'Bearer SECRET-CLIENT-TOKEN'
internal body relayed back  : True
```

The caller's credentials are forwarded to the attacker-named host and
the internal response is relayed back. After this change: `400`, zero
hits, nothing relayed.

A sweep of all 99 routes isolates exactly one leak on unfixed code —
`POST /v1/alpha/search` with `api-key` — and zero after.

## 1. The missing enforcement

**Guarded at the chokepoint, not just the route.**
`select_passthrough_base_url` now validates before returning, in
`proxy_targets.py` and in the parallel copy in `providers/registry.py`,
so a future caller that forgets the header check cannot reopen this.
`/v1/alpha/search` also rejects explicitly with 400, matching its
sibling routes.

## 2. A second gap in the address policy

RFC 6598 shared address space (`100.64.0.0/10`) is not `is_private`, so
it passed the guard — while routing to ISP and cloud-internal
infrastructure. `_is_internal_address` now also rejects anything not
globally routable.

Verified over a 27-vector battery — 0 bypasses, public control
unaffected:

| Vector | Before | After |
|---|---|---|
| `100.64.0.0/10` shared address space | **allowed** | blocked |
| `198.18/15`, TEST-NET, `240/4` | **allowed** | blocked |
| 6to4 / Teredo embedding internal IPv4 | **allowed** | blocked |
| NAT64 `64:ff9b::/96` embedding loopback | **allowed** | blocked |
| loopback, RFC1918, link-local, metadata, IPv4-mapped, userinfo tricks
| blocked | blocked |
| multicast `224.0.0.1` | blocked | blocked |
| public `8.8.8.8` | allowed | allowed |

The category checks are **kept alongside** `is_global` rather than
replaced — `is_global` is `True` for multicast, so a replacement would
have regressed. NAT64 also reports as global, so its embedded IPv4 is
extracted and judged on its own.

## 3. Unauthenticated stall via the resolver

`socket.getaddrinfo` takes no timeout and runs on the calling thread —
the event loop. Since the hostname is caller-supplied, a deliberately
slow-resolving name stalled every other in-flight request; a handful of
concurrent requests made the proxy unresponsive, unauthenticated.

Resolution now runs in a small dedicated pool with a budget
(`HEADROOM_UPSTREAM_RESOLVE_TIMEOUT_S`, default 3s) and fails closed on
overrun, which bounds every caller including the synchronous chokepoint.
`is_safe_upstream_url_async` runs the lookup off the loop, and the three
route handlers that validate a caller-supplied upstream now await it.

Caching was deliberately avoided: a TTL cache in front of a security
decision invites poisoning, and would widen the rebinding window rather
than narrow it.

## Why this survived

The existing tests unit-tested the guard's *logic* but never asserted it
was *reached*. Added enforcement tests at the sinks plus a **sweep over
the whole route table** that fails if any route forwards to a loopback
address — so the next unguarded upstream resolution fails in CI rather
than in a CVE.

All new tests were confirmed failing against the unfixed tree and
passing after.

## Known residual — deliberately not addressed

**DNS rebinding.** Validation and connection resolve the host
separately, so a low-TTL answer can differ between them. Closing this
needs connection-time pinning in the shared `http_client` transport,
which carries every request in the proxy — too broad to fold into this
patch. It should not be described as fixed.

## Compatibility

An endpoint that does not resolve publicly (split-horizon, on-prem) is
now rejected where it previously passed unvalidated.
`HEADROOM_ALLOWED_BASE_URLS` is the documented opt-in, covered by test.
Three existing tests used fictional hostnames and legitimately began
failing; DNS is pinned in them so they keep testing target precedence
rather than depending on the missing guard.

Separately: `docker-compose.yml` has already been hardened since the
advisory — `HEADROOM_PROXY_TOKEN` is now mandatory and ports are
loopback-only — so the "exposed by default" multiplier the advisory
cites no longer applies to the shipped compose.

Full suite: the 3 failures outside this area
(`test_learn/test_integration`,
`test_release_workflows::test_no_native_tls_in_wheel_build_tree`, and a
`test_graceful_shutdown` ordering flake) reproduce on clean `main` and
are unrelated.

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

---------

Co-authored-by: Tejas Chopra <tejas@Tejass-MacBook-Pro.local>
Co-authored-by: Claude Opus 5 <noreply@anthropic.com>
2026-08-21 23:16:59 -07:00

277 lines
8.5 KiB
Python

from __future__ import annotations
import logging
from types import SimpleNamespace
from typing import Any
from unittest.mock import patch
import pytest
from headroom.providers.registry import (
ProviderApiTargets,
ProxyProviderRuntime,
call_client_transport,
create_proxy_backend,
format_backend_status,
)
from headroom.proxy import upstream_guard
class DummyStorage:
def __init__(self) -> None:
self.saved: list[Any] = []
def save(self, metrics: Any) -> None:
self.saved.append(metrics)
class DummyClient:
def __init__(self) -> None:
self._storage = DummyStorage()
self._wrapped_stream: tuple[Any, Any] | None = None
self._original = SimpleNamespace(
chat=SimpleNamespace(completions=SimpleNamespace(create=self._openai_create)),
messages=SimpleNamespace(create=self._anthropic_create, stream=self._anthropic_stream),
)
self.openai_calls: list[dict[str, Any]] = []
self.anthropic_calls: list[dict[str, Any]] = []
def _openai_create(self, **kwargs: Any) -> Any:
self.openai_calls.append(kwargs)
if kwargs["stream"]:
return iter(["chunk-1", "chunk-2"])
return SimpleNamespace(
usage=SimpleNamespace(
completion_tokens=7,
prompt_tokens_details=SimpleNamespace(cached_tokens=3),
)
)
def _anthropic_create(self, **kwargs: Any) -> Any:
self.anthropic_calls.append(kwargs)
return SimpleNamespace(
usage=SimpleNamespace(
output_tokens=5,
cache_read_input_tokens=2,
)
)
def _anthropic_stream(self, **kwargs: Any) -> Any:
self.anthropic_calls.append(kwargs)
return "anthropic-stream"
def _wrap_stream(self, stream: Any, metrics: Any) -> Any:
self._wrapped_stream = (stream, metrics)
return ("wrapped", stream)
def test_proxy_provider_runtime_selects_targets_and_providers() -> None:
runtime = ProxyProviderRuntime(
api_targets=ProviderApiTargets(
anthropic="https://anthropic.example",
openai="https://openai.example",
gemini="https://gemini.example",
cloudcode="https://cloudcode.example",
),
pipeline_providers={
"anthropic": SimpleNamespace(name="anthropic"),
"openai": SimpleNamespace(name="openai"),
},
)
assert runtime.api_target("anthropic") == "https://anthropic.example"
assert runtime.pipeline_provider("openai").name == "openai"
assert runtime.model_metadata_provider({"Authorization": "Bearer sk-ant-api03-test"}) == (
"anthropic"
)
assert runtime.select_passthrough_base_url({"x-goog-api-key": "test"}) == (
"https://gemini.example"
)
# The Azure branch honours the override only after the SSRF guard clears
# the destination (CVE-2026-77775), and `azure.example` does not resolve.
# Pin a public answer so this stays a test of target *precedence*.
with patch.object(
upstream_guard.socket,
"getaddrinfo",
return_value=[(None, None, None, None, ("20.10.10.10", 443))],
):
assert (
runtime.select_passthrough_base_url(
{"api-key": "azure-key", "x-headroom-base-url": "https://azure.example/openai/"}
)
== "https://azure.example/openai"
)
assert runtime.select_passthrough_base_url({}) == "https://openai.example"
def test_create_proxy_backend_uses_injected_backend_types() -> None:
logger = logging.getLogger("test")
anyllm = create_proxy_backend(
backend="anyllm",
anyllm_provider="groq",
bedrock_region=None,
logger=logger,
anyllm_backend_cls=lambda provider, api_base: {
"kind": "anyllm",
"provider": provider,
"api_base": api_base,
},
)
litellm = create_proxy_backend(
backend="bedrock",
anyllm_provider="ignored",
bedrock_region="us-east-1",
logger=logger,
litellm_backend_cls=lambda provider, region, profile_name=None: {
"kind": "litellm",
"provider": provider,
"region": region,
},
)
assert anyllm == {"kind": "anyllm", "provider": "groq", "api_base": None}
assert litellm == {"kind": "litellm", "provider": "bedrock", "region": "us-east-1"}
def test_create_proxy_backend_passes_openai_api_url_to_anyllm() -> None:
"""Regression for #942: --openai-api-url must reach the any-llm backend."""
logger = logging.getLogger("test")
anyllm = create_proxy_backend(
backend="anyllm",
anyllm_provider="openai",
bedrock_region=None,
logger=logger,
openai_api_url="https://custom-provider.example/v1",
anyllm_backend_cls=lambda provider, api_base: {
"provider": provider,
"api_base": api_base,
},
)
assert anyllm == {
"provider": "openai",
"api_base": "https://custom-provider.example/v1",
}
def test_create_proxy_backend_handles_missing_or_direct_backends(
caplog: pytest.LogCaptureFixture,
) -> None:
logger = logging.getLogger("test")
direct = create_proxy_backend(
backend="anthropic",
anyllm_provider="ignored",
bedrock_region=None,
logger=logger,
)
with caplog.at_level(logging.WARNING):
missing = create_proxy_backend(
backend="anyllm",
anyllm_provider="groq",
bedrock_region=None,
logger=logger,
anyllm_backend_cls=lambda provider, api_base: (_ for _ in ()).throw(
ImportError("missing")
),
)
assert direct is None
assert missing is None
assert "any-llm backend not available" in caplog.text
def test_format_backend_status_uses_litellm_provider_metadata(
monkeypatch: pytest.MonkeyPatch,
) -> None:
monkeypatch.setattr(
"headroom.backends.litellm.get_provider_config",
lambda provider: SimpleNamespace(
display_name=provider.upper(),
uses_region=(provider == "bedrock"),
),
)
assert (
format_backend_status(
backend="litellm-bedrock",
anyllm_provider="ignored",
bedrock_region="us-west-2",
)
== "BEDROCK via LiteLLM (region=us-west-2)"
)
assert (
format_backend_status(
backend="litellm-openai",
anyllm_provider="ignored",
bedrock_region=None,
)
== "OPENAI via LiteLLM"
)
def test_call_client_transport_covers_openai_and_anthropic_paths() -> None:
client = DummyClient()
openai_metrics = SimpleNamespace(tokens_output=0, cached_tokens=0)
anthropic_metrics = SimpleNamespace(tokens_output=0, cached_tokens=0)
openai_response = call_client_transport(
"openai",
client,
model="gpt-4o",
messages=[{"role": "user", "content": "hello"}],
stream=False,
metrics=openai_metrics,
temperature=0,
)
openai_stream = call_client_transport(
"openai",
client,
model="gpt-4o",
messages=[{"role": "user", "content": "hello"}],
stream=True,
metrics=openai_metrics,
)
anthropic_response = call_client_transport(
"anthropic",
client,
model="claude-sonnet",
messages=[{"role": "user", "content": "hello"}],
stream=False,
metrics=anthropic_metrics,
max_tokens=32,
)
anthropic_stream = call_client_transport(
"anthropic",
client,
model="claude-sonnet",
messages=[{"role": "user", "content": "hello"}],
stream=True,
metrics=anthropic_metrics,
max_tokens=32,
)
assert openai_response.usage.completion_tokens == 7
assert openai_metrics.tokens_output == 7
assert openai_metrics.cached_tokens == 3
assert openai_stream == ("wrapped", client._wrapped_stream[0])
assert anthropic_response.usage.output_tokens == 5
assert anthropic_metrics.tokens_output == 5
assert anthropic_metrics.cached_tokens == 2
assert anthropic_stream == "anthropic-stream"
assert len(client._storage.saved) == 3
def test_call_client_transport_rejects_unknown_api_style() -> None:
with pytest.raises(ValueError, match="Unsupported api_style"):
call_client_transport(
"unknown",
DummyClient(),
model="gpt-4o",
messages=[],
stream=False,
metrics=SimpleNamespace(),
)