[New-bugs-announce] [issue46899] use of uninitialized value with msan from subprocess_fork_exec

[Yilei Yang]

New submission from Yilei Yang <yileiyang9 at gmail.com>:

The uid & gid variable from https://github.com/python/cpython/blob/9833bb91e4d5c2606421d9ec2085f5c2dfb6f72c/Modules/_posixsubprocess.c#L737-L738 can be passed to the `do_fork_exec` call below uninitialized and cause msan to report use-of-uninitialized-value errors.

Those variables are guarded by call_setgid/call_setuid so they aren't really used uninitialized in practice. It would just be great if we can make it msan clean.

Ideally, the long list of do_fork_exec arguments could also be rewritten in a struct.

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components: Library (Lib)
messages: 414320
nosy: gregory.p.smith, yilei
priority: normal
severity: normal
status: open
title: use of uninitialized value with msan from subprocess_fork_exec
type: enhancement
versions: Python 3.10, Python 3.11, Python 3.9

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue46899>
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