Files
composiohq__composio/python/setup.py
T
Alberto Schiabel d544006a25 fix(sdk): pin the validated address when fetching URLs (SSRF DNS rebinding) (#4172)
Fixes #4151.

## The problem

Both SDKs validated a URL by resolving its hostname, and then handed the
*hostname* to the HTTP client, which resolved it again when it opened
the socket. Two lookups, two answers: a short-TTL record under an
attacker's control answers publicly for the check and with
`169.254.169.254`, `127.0.0.1`, or RFC 1918 space for the connect. The
guard passes and the connection lands inside the network — classic
TOCTOU DNS rebinding, documented in both modules until now as a known
residual.

```mermaid
sequenceDiagram
    participant SDK
    participant DNS as Attacker DNS
    participant Meta as 169.254.169.254
    Note over SDK,Meta: before
    SDK->>DNS: resolve evil.example.com (validate)
    DNS-->>SDK: 93.184.216.34 — passes the guard
    SDK->>DNS: resolve evil.example.com (connect)
    DNS-->>SDK: 169.254.169.254
    SDK->>Meta: GET /latest/meta-data/…
    Meta-->>SDK: credentials
```

## The fix

Resolve once, validate every answer, then connect to the address that
was validated. There is no second lookup left to rebind.

- **Python** — `safe_get` / `safe_request` mount a transport adapter
that swaps the connect target for the duration of the socket connect
only. The `Host` header and TLS SNI keep the hostname, so certificate
verification is unchanged; rewriting `conn._dns_host` for the whole
connection would have sent `Host: <ip>` and offered the IP as SNI,
failing against every real origin. Every fetch call site now goes
through those two helpers, so no `requests.get` sits next to a bare
check any more:
- `_files.py::_fetch_file_from_url`,
`_files.py::FileDownloadable.download`
  - `tool_router_session_files.py::_fetch_url_bytes`
  - `safe_request`, per redirect hop
- **TypeScript** — `assertSafeFetchTarget` returns the validated address
and `ssrfSafeFetch` hands `fetch` a dispatcher pinned to it, re-pinned
per redirect hop. The dispatcher goes to the runtime's own `fetch`, so
callers that stub `globalThis.fetch` keep working. The pinned `lookup`
answers both shapes Node calls it with — the address *list* it uses for
Happy Eyeballs, and the single `(address, family)` it uses when
`autoSelectFamily` is off — since answering in the wrong shape is
rejected as an invalid address.
- A fail-closed peer assertion runs on the Python side before a byte is
written to the socket — redundant while pinning works, and a tripwire if
a urllib3 upgrade ever breaks it.
- `workerd` is unchanged: it already fails closed for user-supplied
URLs.

Redirect *validation* already existed in both SDKs (`safe_request` /
`ssrfSafeFetch`); what was missing was re-pinning each hop.

## Tests

The existing suites could not express this bug: they mock both the
resolver and the HTTP client, so check and use are the same mock. The
new tests use real sockets.

- `python/tests/test_url_safety_pinning.py` — two loopback servers and a
resolver that answers the first lookup with one endpoint and every later
one with another, which is what a short-TTL rebinding record does.
Asserts the rebound endpoint receives **zero** connections, and that
`Host` still carries the hostname. Both tests fail on `next` and pass
here.
- `ts/packages/core/test/utils/pinnedDispatcher.node.test.ts` — a real
server plus a hostname under `.invalid`, which RFC 2606 guarantees never
resolves. A request that arrives proves the connect used the pinned
address and never consulted DNS. The third case shows the contrast:
unpinned, the same fetch cannot resolve at all.
- `ssrfGuard.test.ts` gains assertions that each hop is pinned to that
hop's own validated address.
- `pinnedDispatcher.node.test.ts` also pins with
`setDefaultAutoSelectFamily(false)`, which is the branch Node takes for
the single-address callback.

## Notes

- Supersedes #4157, which diagnosed this correctly. Its post-response
peer check turned out not to hold: with an HTTP/1.0 or `Connection:
close` server, urllib3 detaches the socket (`conn.sock is None`) while
`r.content` still returns the full body, so the check fails open exactly
where exfiltration succeeds. That is why the assertion here runs at
connect time instead.
- The Python package now declares `urllib3>=2` directly. `url_safety`
imports it for `NameResolutionError`, which only exists from 2.0, and
the pinning adapter reaches into 2.x connection internals; `requests`
alone allows 1.x, where `import composio` would have failed outright.
- `@composio/core` gains an `undici` dependency, pinned to `^7`: undici
8 dispatchers are rejected by the `fetch` in every Node version this
package supports (22/24/25, verified). The real-socket test runs on the
full CI matrix, so a future incompatibility fails loudly instead of
silently un-pinning.
- `undici` is imported on first pinned request rather than at module
load: importing it installs a process-wide global dispatcher, which
would have handed the host application's own unrelated `fetch` calls
this package's undici merely because it imported `@composio/core`.
- Residuals, now documented in the modules:
- Requests routed through an environment proxy keep the pre-flight check
only. The proxy resolves the hostname itself and the SDK cannot see or
pin that resolution.
- A process that does perform a pinned fetch still ends up on this
package's `Agent` if nothing had claimed the global dispatcher slot yet.
undici defines that slot non-configurable, so it cannot be handed back —
assigning `undefined` leaves the runtime's own `fetch` asserting on a
missing dispatcher.
2026-08-20 13:34:37 +02:00

42 lines
1.4 KiB
Python

"""
Setup configuration for compsio core.
"""
from pathlib import Path
from setuptools import find_packages, setup
setup(
name="composio",
author="Composio",
author_email="tech@composio.dev",
description="Core package to act as a bridge between composio platform and other services.",
long_description=(Path(__file__).parent / "README.md").read_text(encoding="utf-8"),
long_description_content_type="text/markdown",
url="https://github.com/composiohq/composio",
classifiers=[
"Programming Language :: Python :: 3",
"License :: OSI Approved :: Apache Software License",
"Operating System :: OS Independent",
],
python_requires=">=3.10,<4",
packages=find_packages(include=["composio*"]),
install_requires=[
"pysher>=1.0.8",
"pydantic>=2.11.9",
"composio-client==1.43.0",
"typing-extensions>=4.16.0",
"openai>=2.48.0",
"json-schema-to-pydantic>=0.4.11",
"jsonschema>=4.23.0",
# `get_connection_with_tls_context` (the pinning adapter's mount
# point) is only called by `HTTPAdapter.send` on requests >= 2.32.2.
"requests>=2.32.2",
# `url_safety` imports urllib3 directly and needs 2.x: 1.x has no
# `NameResolutionError` and different connection internals.
"urllib3>=2",
],
include_package_data=True,
)