**Issue:**
- log_target accepted arbitrary paths, allowing authenticated users to write
files as root via fail2ban (e.g., /etc/cron.d/bangui-pwned)
- fail2ban runs as root and opens files specified in log_target
**Solution:**
1. **Model layer validation:** Already existed in GlobalConfigUpdate, prevents
invalid paths before reaching service
2. **Service layer validation:** Added defensive check in update_global_config()
that validates log_target even if model validation is bypassed
3. **New validation helper:** Added validate_log_target() utility that accepts
special values (STDOUT, STDERR, SYSLOG) or paths within allowed directories
**Changes:**
- app/utils/path_utils.py: Added validate_log_target() helper
- app/services/config_service.py: Added service-layer validation before
sending command to fail2ban
- backend/tests: Fixed session_secret length issues in fixtures (min 32 chars)
- backend/tests: Added tests for valid special log targets
- Docs/Backend-Development.md: Documented log_target security requirements
**Test Coverage:**
- Model validation rejects /etc/passwd (existing test)
- Model validation accepts STDOUT, STDERR, SYSLOG special values
- Model validation accepts paths in allowed directories
- Service layer validation tested with special values
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Extract path validation logic into shared helper function in
backend/app/utils/path_utils.py (validate_log_path)
- Refactor AddLogPathRequest to use the helper function
- Apply the same validation to DELETE /api/config/jails/{name}/logpath
endpoint by validating the log_path query parameter
- Return HTTP 422 with descriptive error if validation fails
- Add comprehensive unit tests for path validation
- Update Backend-Development.md with usage examples
This prevents path-traversal attacks on the delete_log_path endpoint
by ensuring all log paths are within allowlisted directories.
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
- Add LogLevel Literal type: CRITICAL, ERROR, WARNING, NOTICE, INFO, DEBUG
- Add log_target validation to accept special values (STDOUT, STDERR, SYSLOG)
or validated file paths within allowed directories
- Update GlobalConfigResponse to use LogLevel type
- Add field_validator for log_target in both GlobalConfigUpdate and
GlobalConfigResponse following the same pattern as AddLogPathRequest
- Add @autouse fixture to test_config_service.py to mock get_settings
- Update existing tests to use uppercase log level values
- Add 12 comprehensive tests for new validation in test_models.py
- Update Features.md to document valid log_target and log_level values
- Add section to Backend-Development.md documenting Literal types and
field_validator patterns with examples
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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>
