fix: resolve symlink bypass in write deny list on macOS#61
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teknium1 merged 1 commit intoNousResearch:mainfrom Feb 27, 2026
Merged
fix: resolve symlink bypass in write deny list on macOS#61teknium1 merged 1 commit intoNousResearch:mainfrom
teknium1 merged 1 commit intoNousResearch:mainfrom
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On macOS, /etc is a symlink to /private/etc. The _is_write_denied()
function resolves the input path with os.path.realpath() but the deny
list entries were stored as literal strings ("/etc/shadow"). This meant
the resolved path "/private/etc/shadow" never matched, allowing writes
to sensitive system files on macOS.
Fix: Apply os.path.realpath() to deny list entries at module load time
so both sides of the comparison use resolved paths.
Adds 19 regression tests in tests/tools/test_write_deny.py.
0xbyt4
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Feb 26, 2026
These tests documented the macOS symlink bypass bug with platform-conditional assertions. The fix and proper regression tests are in PR NousResearch#61 (tests/tools/test_write_deny.py), so remove them here to avoid ordering conflicts between the two PRs.
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Summary
_is_write_denied()was bypassed on macOS for all/etc/*paths/etcis a symlink to/private/etc. The function resolved the input path withos.path.realpath()but deny list entries were stored as literal strings (/etc/shadow), so the resolved path/private/etc/shadownever matched.os.path.realpath()to deny list entries at module load time so both sides use resolved pathsAffected paths (were unprotected on macOS)
/etc/shadow,/etc/passwd,/etc/sudoers/etc/sudoers.d/*,/etc/systemd/*Test plan
tests/tools/test_write_deny.py— all passing on macOS