fix: strip path components from gzip NAME field on decompress#416
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Signed-off-by: Thomas Kowalski <thom.kowa@gmail.com>
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What is this PR?
This PR fixes an arbitrary file write arising from using the raw
NAMEwhen decompressing, without checking whether it is a validNAMEentry, or something that would escape the current working directory.The proposed fix is to ensure the
outfile_namedoes not contain a/, or if it does to strip everything that comes before the last/.This matches what should be expected from a correct input per RFC 1952 §2.3.1, which states that the
NAMEfield stores the original filename "with any directory components removed". It also is consistent with how GNUgziphandles the same case (here).The PR also adds a regression check to confirm the issue is fixed (with an example of an ill-formed input).