Pure-Python fallback of socket.socketpair() doesn’t authenticate peer connection

Vulnerability Description

The “socket” module provides a pure-Python fallback to the socket.socketpair() function for platforms that don’t support AF_UNIX, such as Windows. This pure-Python implementation uses AF_INET or AF_INET6 to create a local connected pair of sockets. The connection between the two sockets was not verified before passing the two sockets back to the user, which leaves the server socket vulnerable to a connection race from a malicious local peer. Platforms that support AF_UNIX such as Linux and macOS are not affected by this vulnerability. Versions prior to CPython 3.5 are not affected due to the vulnerable API not being included.

References

• https://github.com/python/cpython/pull/122134
• https://github.com/python/cpython/issues/122133
• https://mail.python.org/archives/list/security-announce@python.org/thread/WYKDQWIERRE2ICIYMSVRZJO33GSCWU2B/
• http://www.openwall.com/lists/oss-security/2024/07/29/3
• https://github.com/python/cpython/commit/06fa244666ec6335a3b9bf2367e31b42b9a89b20
• https://github.com/python/cpython/commit/0b65c8bf5367625673eafb92f85046a1b31259f2
• https://github.com/python/cpython/commit/220e31adeaaa8436c9ff234cba1398bc49e2bb6c
• https://github.com/python/cpython/commit/5f90abaa786f994db3907fc31e2ee00ea2cf0929
• https://github.com/python/cpython/commit/b252317956b7fc035bb3774ef6a177e227f9fc54
• https://github.com/python/cpython/commit/2621a8a40ba4b2c68ca564671b7daa5da80a4508
• https://github.com/python/cpython/commit/5df322e91a40909e6904bbdbc0c3a6b6a9eead39
• https://github.com/python/cpython/commit/c21a36112a0028d7ac3cf8f480e0dc88dba5922c
• https://github.com/python/cpython/commit/f071f01b7b7e19d7d6b3a4b0ec62f820ecb14660
• https://github.com/python/cpython/commit/31302f5fc24eecd693f0c8aaba7c2840b09b594d
• https://github.com/python/cpython/commit/3f5d9d12c74787fbf3f5891835c85cc15526c86d
• https://github.com/python/cpython/commit/c5655aa6ad120d2ed7f255bebd6e8b71a9c07dde
• https://github.com/python/cpython/commit/e319f774f9e766a2b92949444a2d46081df3363a
• https://github.com/python/cpython/commit/78df1043dbdce5c989600616f9f87b4ee72944e5