Python 3, Are there any known security holes in as

问题:

Are there any known ways for ast.literal_eval(node_or_string)'s evaluation to not actually be safe?

If yes, are patches available for them?

(I already know about PyPy[sandbox], which is presumably more secure, but unless the answers are yes then no, my needs are minor enough that I won't be going that far.)

回答1:

The documentation states it is safe, and there is no bug relative to security of literal_eval in the bug tracker, so you can probably assume it is safe.

Also, according to the source, literal_eval parses the string to a python AST (source tree), and returns only if it is a literal. The code is never executed, only parsed, so there is no reason to be a security risk.

回答2:

>>> code = '()' * 1000000
>>> ast.literal_eval(code)
[1]    3061 segmentation fault (core dumped)  python2

or possibly smaller will crash with SIGSEGV in Python 2. It might be exploitable under some conditions.