[issue2443] uninitialized access to va_list
R. David Murray rdmur...@bitdance.com added the comment: Reducing the priority and updating the target releases, since from the discussion there doesn't appear to be a bug here. -- nosy: +r.david.murray priority: critical - normal stage: - commit review versions: +Python 2.7, Python 3.2 -Python 2.5, Python 2.6, Python 3.0 ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue2443 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue2443] uninitialized access to va_list
Daniel Stutzbach dan...@stutzbachenterprises.com added the comment: Rolland, The va_list is initialized by the function that calls objargs_mktuple. va_start() and va_end() need to be called in the function that takes ... as a parameter, and it is. Not a bug, but +1 on Alexander's patch to consolidate all the #ifdef's for cleanliness. -- nosy: +stutzbach ___ Python tracker rep...@bugs.python.org http://bugs.python.org/issue2443 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue2443] uninitialized access to va_list
Changes by Benjamin Peterson [EMAIL PROTECTED]: -- priority: critical - release blocker ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue2443 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue2443] uninitialized access to va_list
Benjamin Peterson [EMAIL PROTECTED] added the comment: What's the status of this? -- nosy: +benjamin.peterson ___ Python tracker [EMAIL PROTECTED] http://bugs.python.org/issue2443 ___ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue2443] uninitialized access to va_list
Rolland Dudemaine [EMAIL PROTECTED] added the comment: Actually, this thing is more complex to solve than I thought. Specifically, as described in http://www.opengroup.org/onlinepubs/007908775/xsh/stdarg.h.html stdarg requires that variable argument functions have at least one fixed argument. This is implied by the declaration of void va_start(va_list ap, argN);. As explained in the original ticket description, and also described before in the above link, va_start() must be called before any call to va_arg(), and this includes any access to the argument list using __va_copy namely. The problem is that at least objargs_mktuple(), line 2649 of Objects/abstract.c does not have a first fixed argument. __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue2443 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue2443] uninitialized access to va_list
Alexander Belopolsky [EMAIL PROTECTED] added the comment:
This is not a bug. All the reported functions expect va_list argument
to be initialized before being called. AFAICT, they are consistently
used in this way. For example,
PyObject *
PyObject_CallFunctionObjArgs(PyObject *callable, ...)
{
PyObject *args, *tmp;
va_list vargs;
if (callable == NULL)
return null_error();
/* count the args */
va_start(vargs, callable);
args = objargs_mktuple(vargs);
va_end(vargs);
if (args == NULL)
return NULL;
tmp = PyObject_Call(callable, args, NULL);
Py_DECREF(args);
return tmp;
}
This may need to be clarified in the docs. For example, PyString_FromFormatV
does not mention that vargs needs to be
initialized: http://docs.python.org/dev/c-
api/string.html#PyString_FromFormatV. On the other hand, this may be
obvious to most C programmers.
I suggest to close this issue as invalid.
--
nosy: +belopolsky
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[issue2443] uninitialized access to va_list
Alexander Belopolsky [EMAIL PROTECTED] added the comment: On the second thought the macro dance highlighted by OP belongs to pyport.h. Attached patch defines Py_VA_COPY macro and uses it to simplify va_list copying code. -- keywords: +patch Added file: http://bugs.python.org/file9849/issue2443.diff __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue2443 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue2443] uninitialized access to va_list
Christian Heimes [EMAIL PROTECTED] added the comment: Looks like a good idea to me -- priority: high - critical resolution: - accepted __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue2443 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue2443] uninitialized access to va_list
Rolland Dudemaine [EMAIL PROTECTED] added the comment:
This is what I meant. The initialization should be done by calling
va_start(count_va); as you described.
In the files and lines I reported though, this is not called.
I'll file a patch for it soon.
--Rolland Dudemaine
Alexander Belopolsky wrote:
Alexander Belopolsky [EMAIL PROTECTED] added the comment:
This is not a bug. All the reported functions expect va_list argument
to be initialized before being called. AFAICT, they are consistently
used in this way. For example,
PyObject *
PyObject_CallFunctionObjArgs(PyObject *callable, ...)
{
PyObject *args, *tmp;
va_list vargs;
if (callable == NULL)
return null_error();
/* count the args */
va_start(vargs, callable);
args = objargs_mktuple(vargs);
va_end(vargs);
if (args == NULL)
return NULL;
tmp = PyObject_Call(callable, args, NULL);
Py_DECREF(args);
return tmp;
}
This may need to be clarified in the docs. For example, PyString_FromFormatV
does not mention that vargs needs to be
initialized: http://docs.python.org/dev/c-
api/string.html#PyString_FromFormatV. On the other hand, this may be
obvious to most C programmers.
I suggest to close this issue as invalid.
--
nosy: +belopolsky
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title: Define Py_VA_COPY macro as a cross-platform replacement for gcc
__va_copy - uninitialized access to va_list
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[issue2443] uninitialized access to va_list
New submission from Rolland Dudemaine [EMAIL PROTECTED]:
In many files, the following code is present (with slight variations,
but the important part is there) :
static PyObject *
objargs_mktuple(va_list va)
{
int i, n = 0;
va_list countva;
PyObject *result, *tmp;
#ifdef VA_LIST_IS_ARRAY
memcpy(countva, va, sizeof(va_list));
#else
#ifdef __va_copy
__va_copy(countva, va);
#else
countva = va;
#endif
#endif
...
memcpy() is accessing va_list before it is initialized.
Before the first access to a va_list type variable, and after the last
access to that variable, calls to va_start() and va_end() must be made
to initialize and free the variable.
Such behaviour should be corrected in the following files :
- Objects/abstract.c, line 1901
- Objects/stringobject.c, line 162
- getargs.c, line 66
- getargs.c, line 1188
- modsupport.c, line 479
--
components: Build
messages: 64234
nosy: rolland
severity: normal
status: open
title: uninitialized access to va_list
type: compile error
versions: Python 2.5, Python 2.6, Python 3.0
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[issue2443] uninitialized access to va_list
Christian Heimes [EMAIL PROTECTED] added the comment: Can you provide a patch for 2.6 against the latest svn checkout of the trunk please? -- components: +Interpreter Core -Build nosy: +tiran priority: - high __ Tracker [EMAIL PROTECTED] http://bugs.python.org/issue2443 __ ___ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
