fix(decompress): harden toFile against symlink path-escape - #140
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ranxianglei wants to merge 3 commits into
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fix(decompress): harden toFile against symlink path-escape#140ranxianglei wants to merge 3 commits into
ranxianglei wants to merge 3 commits into
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resolveToFilePath checked containment against the literal resolved path, so a symlink inside an allowed root (e.g. /tmp) pointing elsewhere could pass the check and write outside the allowed roots. Resolve symlinks in the longest existing ancestor of the target before the containment check, and compare against realpath'd roots (tmpdir() itself often sits behind a symlink, e.g. /var -> /private/var on macOS). Also null-guard args.blockId before trim() for robustness. Extracted from #119 (lsmir2).
…k (Windows) existsSync follows symlinks, so a symlink whose target does not (yet) exist reads as non-existent and was skipped by the ancestor walk — the unresolved link component then passed the containment check even though writing through it would land outside the allowed roots. Resolve each suffix component via lstatSync/readlinkSync so dangling symlinks (e.g. to a non-existent /etc on Windows) are caught. Adds a dedicated dangling-symlink test.
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What
resolveToFilePathchecked path containment against the literal resolved path. A symlink inside an allowed root (e.g./tmp) that points outside the allowed roots could pass the check and letdecompress --toFilewrite to an arbitrary filesystem location.Fix
tmpdir()itself often sits behind a symlink (/var -> /private/varon macOS), so the string forms would otherwise diverge and reject legitimate writes.args.blockIdbeforetrim()for robustness.Test
New regression test
decompress toFile rejects paths that escape an allowed root via a symlink: creates a symlink inside an allowed jail pointing at/etc, asserts the write is rejected. Fails on the old code (literal-path check), passes with the fix.Validation
Scope
Minimal, isolated, no cross-repo dependency. Extracted from #119 (thanks @21307369 for the original implementation). This is the high-priority security item from the #119 review split — the rest of #119 (the
/compactpipeline, clean-output, i18n) is being split into separate PRs.