Restrict monitored log paths to a configurable allowlist of safe directories
to prevent authenticated users from instructing fail2ban to monitor arbitrary
files on the system, which could leak contents via fail2ban logging.
Changes:
- Add 'allowed_log_dirs' setting to Settings (defaults to /var/log, /config/log)
- Add @field_validator to AddLogPathRequest to validate log paths at request time
- Validator resolves paths to canonical form and checks against allowed prefixes
- Use Path.is_relative_to() to prevent prefix bypass attacks like /var/log_evil
- Add comprehensive tests for valid/invalid paths and symlink handling
- Update Features.md and Backend-Development.md with security documentation
Security improvements:
- Blocks access to sensitive files (/etc/shadow, /etc/passwd, etc.)
- Resolves symlinks before validation to prevent escape routes
- Uses proper path comparison instead of string prefix matching
- Configurable via BANGUI_ALLOWED_LOG_DIRS environment variable
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Lukas
308cf680a7