Validate log_file paths to prevent arbitrary file writes#3656
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eddieran wants to merge 1 commit intopre-commit:mainfrom
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Validate log_file paths to prevent arbitrary file writes#3656eddieran wants to merge 1 commit intopre-commit:mainfrom
eddieran wants to merge 1 commit intopre-commit:mainfrom
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A hook manifest can specify a `log_file` with an absolute path or path traversal sequences (e.g. `../../../etc/cron.d/malicious`), causing pre-commit to write hook output to arbitrary locations on the host filesystem via `output.write_line_b`. Reject absolute paths and paths that traverse above the working directory during manifest validation. Fixes #3655
Member
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there's no such thing as a "malicious remote hook" every part of pre-commit is opt in please don't send ai slop prs |
Member
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also lol if they're truly evil they ALREADY HAVE ARBITRARY CODE EXECUTION |
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Summary
log_filein hook manifests (.pre-commit-hooks.yaml) accepts arbitrary strings and is passed directly toopen(logfile_name, 'ab')inoutput.write_line_b. A malicious remote hook manifest can setlog_fileto an absolute path (e.g./etc/cron.d/malicious) or use path traversal (../../../etc/passwd) to write hook output to arbitrary locations on the host filesystem.Fix
Add path validation for
log_fileinclientlib.pyduring manifest schema validation:../foo)The validation is applied via
check_log_fileon theMANIFEST_HOOK_DICTschema, which also propagates toCONFIG_HOOK_DICTandLOCAL_HOOK_DICT.Test plan
test_check_log_file_valid— verifies relative paths likeoutput.log,logs/hook.log, and empty string pass validationtest_check_log_file_invalid— verifies absolute paths and..traversal paths are rejected withcfgv.ValidationErrorFixes #3655