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Merged
kumaraditya303 merged 3 commits into from
Apr 10, 2023
Merged

gh-83004: Harden msvcrt init #103383

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18820c1
gh-83004: Harden msvcrt init
erlend-aasland Apr 8, 2023
528221f
Don't leak module object on error
erlend-aasland Apr 8, 2023
ad93c2a
Revert moving 'st'
erlend-aasland Apr 8, 2023
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41 changes: 29 additions & 12 deletions PC/msvcrtmodule.c
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Original file line numberDiff line numberDiff line change
Expand Up@@ -609,11 +609,11 @@ PyMODINIT_FUNC
PyInit_msvcrt(void)
{
int st;
PyObject *d, *version;
PyObject *m = PyModule_Create(&msvcrtmodule);
if (m == NULL)
if (m == NULL) {
return NULL;
d = PyModule_GetDict(m);
}
PyObject *d = PyModule_GetDict(m); // Borrowed ref.

/* constants for the locking() function's mode argument */
insertint(d, "LK_LOCK", _LK_LOCK);
Expand DownExpand Up@@ -644,30 +644,47 @@ PyInit_msvcrt(void)
#ifdef _VC_ASSEMBLY_PUBLICKEYTOKEN
st = PyModule_AddStringConstant(m, "VC_ASSEMBLY_PUBLICKEYTOKEN",
_VC_ASSEMBLY_PUBLICKEYTOKEN);
if (st < 0) return NULL;
if (st < 0) {
goto error;
}
#endif
#ifdef _CRT_ASSEMBLY_VERSION
st = PyModule_AddStringConstant(m, "CRT_ASSEMBLY_VERSION",
_CRT_ASSEMBLY_VERSION);
if (st < 0) return NULL;
if (st < 0) {
goto error;
}
#endif
#ifdef __LIBRARIES_ASSEMBLY_NAME_PREFIX
st = PyModule_AddStringConstant(m, "LIBRARIES_ASSEMBLY_NAME_PREFIX",
__LIBRARIES_ASSEMBLY_NAME_PREFIX);
if (st < 0) return NULL;
if (st < 0) {
goto error;
}
#endif

/* constants for the 2010 crt versions */
#if defined(_VC_CRT_MAJOR_VERSION) && defined (_VC_CRT_MINOR_VERSION) && defined(_VC_CRT_BUILD_VERSION) && defined(_VC_CRT_RBUILD_VERSION)
version = PyUnicode_FromFormat("%d.%d.%d.%d", _VC_CRT_MAJOR_VERSION,
_VC_CRT_MINOR_VERSION,
_VC_CRT_BUILD_VERSION,
_VC_CRT_RBUILD_VERSION);
st = PyModule_AddObject(m, "CRT_ASSEMBLY_VERSION", version);
if (st < 0) return NULL;
PyObject *version = PyUnicode_FromFormat("%d.%d.%d.%d",
_VC_CRT_MAJOR_VERSION,
_VC_CRT_MINOR_VERSION,
_VC_CRT_BUILD_VERSION,
_VC_CRT_RBUILD_VERSION);
if (version == NULL) {
goto error;
}
st = PyModule_AddObjectRef(m, "CRT_ASSEMBLY_VERSION", version);
Comment on lines +673 to +676

@zoobazoobaApr 11, 2023

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@erlend-aasland Just FYI, the modsupport functions allow passing in NULL provided an error has already occurred, and they just let it chain. So the code here was fine before.

No need to revert now though.

@erlend-aaslanderlend-aaslandApr 11, 2023

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TIL! Sorry for not waiting on your review.

@erlend-aaslanderlend-aaslandApr 11, 2023

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However, there was a leak if PyModule_AddObject failed, since that API only eat refs if successful.

@kumaraditya303kumaraditya303Apr 12, 2023

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Sorry I should have been more careful in this.

Py_DECREF(version);
if (st < 0) {
goto error;
}
#endif
/* make compiler warning quiet if st is unused */
(void)st;

return m;

error:
Py_DECREF(m);
return NULL;
}