gh-145335: validate file descriptor in os.fpathconf and os.pathconf#145341
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gourijain029-del wants to merge 1 commit intopython:mainfrom
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gh-145335: validate file descriptor in os.fpathconf and os.pathconf#145341gourijain029-del wants to merge 1 commit intopython:mainfrom
gourijain029-del wants to merge 1 commit intopython:mainfrom
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You've done a whole lot more than that, there are so many changes the diff won't even render. And furthermore, your new test (which should have been added to an existing file) fails. |
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Problem
Calling os.fpathconf(-1, name) or os.pathconf(-1, name) on macOS (and other platforms) caused a segmentation fault. The CPython implementation passed the negative file descriptor straight to the underlying
fpathconf
system call, which is undefined behavior and crashes the interpreter.
Fix
Added a guard in
Modules/posixmodule.c
(
os_fpathconf_impl
) that checks fd < 0.
When the descriptor is negative, the function now raises a clear ValueError with the message “file descriptor cannot be negative” and returns -1 to signal the error.
The existing error‑handling path (errno handling) remains unchanged for valid descriptors.
Regression Test
Introduced
Lib/test/test_os_pathconf.py
which verifies that both os.fpathconf(-1, 1) and os.pathconf(-1, 1) raise ValueError with the expected message.
The test runs as part of the standard CPython test suite, ensuring the fix stays in place.
Impact
Eliminates a hard crash for a common misuse pattern.
Provides a Python‑level exception that developers can catch, matching the behaviour of other os.* functions that validate file descriptors.
No functional changes for valid descriptors; all existing semantics are preserved.
Related Issue
Fixes issue #145335 (segfault from os.pathconf(-1, 1)).
os.pathconf(-1, 1)#145335