Move debug log defaults out of /tmp and reject symlinks - #38
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The default debug_log_path and resolver_debug_log_path were in /tmp, which is world-writable on shared hosts. An attacker who pre-creates a symlink at /tmp/historian-debug.log pointing at e.g. an authorized_keys file could trick Historian (with debug mode on) into overwriting an arbitrary file, because _prepare_private_file opened with O_CREAT and no O_NOFOLLOW/O_EXCL. Two defenses, per the issue: - Move defaults under the XDG data dir (~/.local/share/historian/), which is not world-writable, matching how database_path already works. - Add O_NOFOLLOW to _prepare_private_file so a symlinked target is rejected at open time rather than followed, even for custom paths. Updates config.py, config.example.json, and docs/debugging.md. Adds tests for the new defaults and symlink rejection.
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Summary
The default
debug_log_pathandresolver_debug_log_pathlived in/tmp(world-writable on shared hosts). An attacker who pre-creates a symlink at/tmp/historian-debug.log→ e.g.~/.ssh/authorized_keyscould trick Historian, with debug mode on, into overwriting an arbitrary file, because_prepare_private_fileopened withO_CREATand noO_NOFOLLOW/O_EXCL.This applies the issue's recommended Option 1 plus Option 2 as defense-in-depth:
~/.local/share/historian/), which is not world-writable — matching howdatabase_pathalready works. Updated inconfig.py,config.example.json, anddocs/debugging.md.O_NOFOLLOWto_prepare_private_fileso a symlinked target is rejected at open time rather than followed, even when a user sets a custom path.New tests verify the defaults no longer point at
/tmpand that a symlink target is refused (and the pointed-at file left untouched).Closes #23.
Test commands run
All 70 tests pass; compile check clean.