coderdailyoneandClaude Fable 5 18ac388162 security: pin fetched connections to the vetted address (close DNS rebinding) ...

guard.get_checked previously resolved a name for the address check and then let
the client resolve it again to connect, so a ~0-TTL record could flip to
127.0.0.1 (or the metadata endpoint) between the two — the exact gap the module
docstring called out as "not covered".

Every hop now connects to the address that passed its check: the request URL
carries the vetted IP, Host keeps the original name (and explicit port) for
virtual hosting, and the sni_hostname extension keeps the TLS handshake — and
certificate verification — against the name. Literal-IP URLs are unchanged.
Redirect Locations are resolved against the logical URL, and the final logical
URL rides resp.extensions["logical_url"] so web_fetch reports the name, not the
pinned address.

Verified against a local TLS server whose cert carries only DNS:pinned.test:
the pinned request (URL=127.0.0.1, sni_hostname=pinned.test) verifies and the
server sees Host: pinned.test; the same request without the extension fails
with "IP address mismatch" — httpcore does verify certificates against
sni_hostname, not the URL host.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

2026-07-31 10:16:09 +01:00

..

__init__.py

OpenWorker: initial import

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fetch.py

security: pin fetched connections to the vetted address (close DNS rebinding)

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guard.py

security: pin fetched connections to the vetted address (close DNS rebinding)

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providers.py

OpenWorker: initial import

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tool.py

OpenWorker: initial import

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