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tarfs: Fix two input validation issues.
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Authored by des on Feb 29 2024, 7:47 PM.
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F132564711: D44161.id.diff
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F132564709: D44161.id135257.diff
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Details

Summary
  • Reject hard or soft links with an empty target path. Currently, a debugging kernel will hit an assertion in tarfs_lookup_path() while a non-debugging kernel will happily create a link to the mount root.
  • Use a temporary variable to store the result of the link target path, and copy it to tnp->other only once we have found it to be valid. Otherwise we error out after creating a reference to the target but before incrementing the target's reference count, which results in a use-after-free situation in the cleanup code.
  • Correctly return ENOENT from tarfs_lookup_path() if the requested path was not found and create_dirs is false. Luckily, existing callers did not rely solely on the return value.

MFC after: 3 days
PR: 277360
Sponsored by: Juniper Networks, Inc.
Sponsored by: Klara, Inc.

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rG FreeBSD src repository
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Event Timeline

des requested review of this revision.Feb 29 2024, 7:47 PM

fix link to nonexistent target

This revision is now accepted and ready to land.Mar 1 2024, 9:48 PM
This revision was automatically updated to reflect the committed changes.