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classification
Title: Potential AV in vgetargskeywords
Type: Stage:
Components: Interpreter Core Versions: Python 2.2
process
Status: closed Resolution: fixed
Dependencies: Superseder:
Assigned To: gvanrossum Nosy List: glchapman, gvanrossum, loewis
Priority: normal Keywords:

Created on 2002-03-24 16:30 by glchapman, last changed 2022-04-10 16:05 by admin. This issue is now closed.

Files
File name Uploaded Description Edit
getargs.c.diff glchapman, 2002-03-24 16:30
getargs.c.2.diff glchapman, 2002-03-27 17:20
Messages (5)
msg9941 - (view) Author: Greg Chapman (glchapman) Date: 2002-03-24 16:30
If you are dumb enough to do what I just did, pass a 
dictionary with non-string keys to 
PyEval_CallObjectWithKeyWords, you may cause an access 
violation in Python (if the call ends up going through 
PyArg_ParseTupleAndKeywords).  The problem is in the 
section of vgetargskeywords which checks for 
extraneous keyword arguments: it does not check to 
make sure PyString_AsString(key) succeeded.  Attached 
is a simple patch.
msg9942 - (view) Author: Martin v. Löwis (loewis) * (Python committer) Date: 2002-03-27 12:40
Logged In: YES 
user_id=21627

I think you need to clear the previous exception which is
indicated by the NULL return value (or just let it trough as
is).
msg9943 - (view) Author: Greg Chapman (glchapman) Date: 2002-03-27 16:55
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user_id=86307

I don't think calling PyErr_Clear is necessary given the 
current implementation; both PyErr_Clear and 
PyErr_SetString ultimately call PyErr_Restore, which clears 
the old error.

As for passing the error through, that might be a better 
choice.  I put in the PyErr_SetString to try to follow the 
behavior of PyEval_EvalCodeEx when it gets non-string keys 
in a keyword dict.
msg9944 - (view) Author: Greg Chapman (glchapman) Date: 2002-03-27 17:20
Logged In: YES 
user_id=86307

On second thought, perhaps I didn't follow 
PyEval_EvalCodeEx closely enough.  PyString_AsString can 
succeed for some non-string types (unicode, etc.), but 
these keys would not work if passed to PyEval_EvalCodeEx.  
So attached is a second version of the patch which calls 
PyString_Check before calling PyString_AsString. 
msg9945 - (view) Author: Guido van Rossum (gvanrossum) * (Python committer) Date: 2002-04-04 16:27
Logged In: YES 
user_id=6380

Fixed in CVS.  Thanks!
History
Date User Action Args
2022-04-10 16:05:08adminsetgithub: 36322
2002-03-24 16:30:10glchapmancreate