phar: reject extractTo() when destination parent escapes via symlink#43
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phar: reject extractTo() when destination parent escapes via symlink#43
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Phar::extractTo() builds the target path as dest + "/" + entry_path. CWD_EXPAND validates entry_path against ".." traversal but doesn't resolve symlinks. A pre-existing symlink in the destination (e.g., /dest/subdir -> /etc) writes the extracted file outside the intended root. After creating the parent directory, resolve it with VCWD_REALPATH and verify it stays under dest. Return FAILURE if it escapes so the caller throws a PharException.
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Promoted to php#21808. |
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Fixes destination-side symlink traversal in
Phar::extractTo().extractTo()builds the target path asdest + "/" + entry_path.CWD_EXPANDvalidates the entry path against..traversal but doesn't resolve symlinks. A pre-existing symlink in the destination (e.g.,/dest/subdir -> /etc) causes the extracted file to land outside the intended root.After creating the parent directory, resolve it with
VCWD_REALPATHand verify it stays underdest. ReturnFAILUREif it escapes so the caller throws aPharException.The test skips on Windows only when
SeCreateSymbolicLinkPrivilegeis absent. Without it,symlink()returns false without error, so no symlink exists in the destination,extractTo()succeeds, and the test outputsEXTRACTED (unexpected)instead of thePharExceptionthat--EXPECTF--requires.