Do not follow a .py symlink out of the scan root - #11
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os.walk does not follow directory symlinks, but a file symlink is yielded and read through. A tree containing `src/x.py -> ~/.ssh/id_rsa` therefore had that file opened by `codesnake check src/`, which SECURITY.md already lists as in scope: reading files outside the analyzed paths. The read is not the whole of it. A parse failure becomes SYN001 and the text report prints the offending source line, so content from the target reaches the output. Reproduced with a benign stand-in: pointing at a config file whose first two lines are valid Python printed the third verbatim, credential and all. On a public repository that lands in the CI log, and the attacker chooses the target, so they choose which line fails to parse. The walk now skips a symlink whose resolved path leaves the root. Symlinks that stay inside it are followed as before -- this is containment, not a ban on symlinks -- and an explicit file argument is still read as given, since naming a file is a deliberate act. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_0114gUUe4CxYr8W8oC95ffmD
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os.walk does not follow directory symlinks, but a file symlink is yielded and
read through. A tree containing
src/x.py -> ~/.ssh/id_rsatherefore had thatfile opened by
codesnake check src/, which SECURITY.md already lists as inscope: reading files outside the analyzed paths.
The read is not the whole of it. A parse failure becomes SYN001 and the text
report prints the offending source line, so content from the target reaches
the output. Reproduced with a benign stand-in: pointing at a config file whose
first two lines are valid Python printed the third verbatim, credential and
all. On a public repository that lands in the CI log, and the attacker chooses
the target, so they choose which line fails to parse.
The walk now skips a symlink whose resolved path leaves the root. Symlinks
that stay inside it are followed as before -- this is containment, not a ban
on symlinks -- and an explicit file argument is still read as given, since
naming a file is a deliberate act.
Co-Authored-By: Claude Opus 5 noreply@anthropic.com
Claude-Session: https://claude.ai/code/session_0114gUUe4CxYr8W8oC95ffmD