π‘οΈ Sentinel: [HIGH] Fix SSRF bypass via HTTP redirects in urllib.request#334
π‘οΈ Sentinel: [HIGH] Fix SSRF bypass via HTTP redirects in urllib.request#334seonghobae wants to merge 2 commits into
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Python's urllib.request.urlopen automatically follows HTTP redirects (301, 302, etc.) natively by default. When the CLI or webhook dispatcher takes user-provided URLs (like webhook target URL or CLI --push url), we first validate the host and scheme, but a malicious target could return a redirect to `http://localhost` or `http://169.254.169.254`. Since `urlopen` blindly follows this redirect internally, the SSRF check is bypassed. This commit introduces a custom `NoRedirectHandler` extending `urllib.request.HTTPRedirectHandler` that explicitly raises an `HTTPError` when a redirect is attempted, preventing SSRF escapes to internal networks.
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β¦n controlplane.py The GitHub CI Semgrep OSS check failed because it flagged `from importlib import resources` as a Python 3.7+ compatibility issue, despite `pyproject.toml` requiring `>=3.9`. As documented in `.jules/sentinel.md` learnings, this CI rule failure can be bypassed by using a flat import `import importlib.resources` along with an inline suppression directive `# nosemgrep: python.lang.compatibility.python37.python37-compatibility-importlib2` to ensure formatting tools like `isort` and `black` do not line-wrap the statement and break the directive.
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π¨ Severity: HIGH
π‘ Vulnerability: Server-Side Request Forgery (SSRF) bypass due to
urllib.request.urlopenautomatically following HTTP redirects natively.π― Impact: An attacker can bypass strict upfront domain and IP validation by pointing the application to a safe external server that issues a 301/302 HTTP redirect to an internal IP (like 127.0.0.1 or AWS Metadata 169.254.169.254). The default opener follows this redirect.
π§ Fix: Swapped out the default
urlopenwith a custombuild_opener(NoRedirectHandler())that explicitly blocks and errors on redirects by overridingredirect_requestin a customurllib.request.HTTPRedirectHandler.β Verification: Ran unit tests and mocked
OpenerDirector.opento ensure no functionality is broken and code is fully covered.PR created automatically by Jules for task 6164294174331742221 started by @seonghobae