External variable 'filename' used in file path
25def push2tg(filename: str, group_id: str, bot_token: str) -> dict:
26 result = {"status": -1, "code": -1}
27 try:
28 with open(filename, "rb") as f:29 sent = telegram.Bot(bot_token).send_photo(photo=f, chat_id=group_id)
30 logger.info(f"Pushing {filename} to telegram group.")
31 print("返回结果：", sent)
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