While embedding the Python 2.7 interpreter in an application, I have encountered a crash when the built-in function 'execfile' is invoked with one argument.

A file is attached, execfile_invoke.c, that reproduces the crash. The reproduction steps on my machine are the following:

% gcc -o execfile_invoke execfile_invoke.c -I/usr/include/python2.7 -L/usr/lib -lpthread -ldl -lutil -lm -lpython2.7 -Xlinker -export-dynamic
% ./execfile_invoke
Call execfile with one argument...
Segmentation fault
% 

I am using the following version of Python.

Python 2.7.3 (default, Mar 13 2014, 11:03:55) 
[GCC 4.7.2] on linux2

The crash appears to occur because a call to PyEval_GetGlobals returns a NULL PyObject*,

globals = PyEval_GetGlobals();

and PyDict_GetItemString is called before a NULL check is performed.

In the Python 3 function builtin_exec, globals and locals are checked for NULL. If either is NULL, an exception with message "globals and locals cannot be NULL" is set.

if (!globals || !locals) {
     PyErr_SetString(PyExc_SystemError,
            "globals and locals cannot be NULL");
   return NULL;
}

I created a patch to add a check for NULL globals or locals. The file execfile.patch is attached. A system error is set with the message "globals and locals cannot be NULL" if either is NULL.

An open question I have is how should I create tests for this patch? I verified that the crash doesn't occur when I run the attached execfile_invoke.c program.

Python 2.7 is close to it's end of life, Python 3 doesn't have execfile(), and this issue has no activity since 2014. I close the issue.

nosy: + vstinner
messages: + msg342548

resolution: out of date
stage: resolved