libutil: Make RestoreSink use *at system calls on UNIX#14597
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libutil: Make RestoreSink use *at system calls on UNIX#14597
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…UL bytes better Same utility as in lix's change I3caf476e59dcb7899ac5a3d83dfa3fb7ceaaabf0. Co-authored-by: eldritch horrors <pennae@lix.systems>
xokdvium
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As stated in Nix team meeting, definite improvement, and seems good to merge.
Longer-term, I'd like us to get rid of the open()s and have the caller pass in the parent dir fd, and preferably only do single-component O_NOFOLLOW openats, since O_NOFOLLOW only applies to the final component.
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xokdvium
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Nov 20, 2025
This is necessary to ban symlink following. It can be considered a defense in depth against issues similar to CVE-2024-45593. By slightly changing the API in a follow-up commit we will be able to mitigate the symlink following issue for good.
Now the intermediate symlink following issue should be completely plugged.
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Just noticed that I've missed some CLOEXEC. Added them, though I doubt it would matter in practice |
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Motivation
This is necessary to ban symlink following. It can be considered
a defense in depth against issues similar to CVE-2024-45593.
Context
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