ArchiveReader: Preserve special permission bits during extraction - #839
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ArchiveReader: Preserve special permission bits during extraction#839maksim-romanov wants to merge 1 commit into
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ArchiveReader.setFileAttributes was losing the sticky/set-user-ID/set-group-ID bits on every extracted regular file and directory, for two independent reasons: 1. apple#816 masked the applied fchmod mode to 0o777 to strip file-type bits picked up from the archived mode, but 0o777 also strips the sticky/set-user-ID/set-group-ID bits (0o7000) that extraction should keep. 2. setFileAttributes called fchmod before fchown. On Darwin, fchown clears set-user-ID/set-group-ID as a security measure, even when the new owner/group match the file's existing owner/group, so applying ownership after the mode silently drops those bits regardless of (1). Fix: apply ownership first, then fchmod with a 0o7777 mask (the full POSIX permission field, still excluding unrelated file-type bits). Added preserveSpecialPermissionBits() in ArchiveReaderTests.swift: extracts a 0o1777 directory and a 0o6755 regular file (owned by the current uid/gid so fchown succeeds without root) and asserts both survive extraction. Verified the test fails without the fix (reproducing the truncated values reported in the issues) and passes with it. swift test --filter ContainerizationArchiveTests (51 tests) and swift format lint --strict both clean. Closes apple#818 Closes apple#819
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ArchiveReader.setFileAttributes was losing the sticky/set-user-ID/set-group-ID
bits on every extracted regular file and directory, for two independent
reasons:
fchmodmode to0o777to strip file-type bitspicked up from the archived mode, but
0o777also strips thesticky/set-user-ID/set-group-ID bits (
0o7000) that extraction shouldkeep.
setFileAttributescalledfchmodbeforefchown. On Darwin,fchownclears set-user-ID/set-group-ID as a security measure, even when the new
owner/group match the file's existing owner/group, so applying ownership
after the mode silently drops those bits regardless of (1).
Fix: apply ownership first, then
fchmodwith a0o7777mask (the fullPOSIX permission field, still excluding unrelated file-type bits).
Added
preserveSpecialPermissionBits()inArchiveReaderTests.swift:extracts a
0o1777directory and a0o6755regular file (owned by thecurrent uid/gid so
fchownsucceeds without root) and asserts both surviveextraction. Verified the test fails without the fix (reproducing the
truncated values reported in the issues) and passes with it.
swift test --filter ContainerizationArchiveTests(51 tests) andswift format lint --strictboth clean.Closes #818
Closes #819