External variable 'path' used in file path
425 :type path: str
426
427 """
428 with open(path, "wb") as file_:429 pickle.dump(self, file_, protocol=pickle.HIGHEST_PROTOCOL)
External variable 'path' used in file path
65 :rtype: :py:class:`~.SimDir`
66
67 """
68 with open(path, "rb") as file_: 69 sim = pickle.load(file_)
70
71 if not isinstance(sim, SimDir):
Description
Python's open() function can take in a relative or absolute path and read its file contents.
If a user is provided direct access to the path that is opened, it can have serious security risks.
Bad practice
def read_file(path):
with open(os.path.join('some/path', path)) as f:
f.read()
# Someone can exploit `read_file` and see your secrets this way:
read_file('../../../secrets.txt')
Recommended
Either use a static path:
def read_file(path):
with open('some/path/to/file.txt') as f:
f.read()
Or, do some kind of validation to make sure you're not allowing arbitrary file access:
def read_file(filename):
if filename not in ('x.txt', 'y.txt'):
return 'Invalid filename'
with open(os.path.join('some/path', path)) as f:
f.read()
References
- OWASP Top 10 2021 Category A01 - Broken Access Control
- OWASP Top 10 2021 Category A04 - Insecure Design
- CWE-73 External Control of File Name or Path