Reject tar hard link targets that escape the extraction destination - #30878
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Reject tar hard link targets that escape the extraction destination#30878shaggyinsomniac wants to merge 1 commit into
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Hard link targets are re-rooted at the extraction destination, so the existing relative-path guard never fires for them and a linkname like '../foo' can point outside the destination directory. Check the raw linkname for '..' segments before creating the link, similar to how GNU tar refuses such members by default.
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Fixes #30875.
What
For hard links,
maybeDeprefixSymlinkis called withforceExtractRootRelative=true, which always returns an absolute fragment. That means the!targetName.isAbsolute()gate on the existing containment check can never fire for hard links, only for symlinks — so a tar member like a hard link to../fooslips past the guard and the link gets created outside the extraction destination.This PR checks the raw linkname (marker-stripped with
toRawBytesString) for..segments before creating the hard link, similar to how GNU tar refuses such members by default. Everything else in the extraction path is untouched.Testing
testDecompressTarWithHardlinkEscapenext to the existing symlink/regular-file escape tests: builds a tar.gz with a hard linklink->../fooand asserts decompression throws.//src/test/java/.../decompressor:DecompressorTestssuite passes locally (100/100).