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Issue #15905: Fix theoretical buffer overflow in handling of sys.argv[0], 

prefix and exec_prefix if the operation system does not obey MAXPATHLEN.
This commit is contained in:
Christian Heimes 2013-07-22 12:54:21 +02:00
parent 7fca717815 60a6067709
commit de0e63bd9c
3 changed files with 19 additions and 7 deletions
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3
Misc/NEWS
View File

@ -10,6 +10,9 @@ What's New in Python 3.4.0 Alpha 1?
Core and Builtins
-----------------
- Issue #15905: Fix theoretical buffer overflow in handling of sys.argv[0],
prefix and exec_prefix if the operation system does not obey MAXPATHLEN.
- Issue #18408: Fix many various bugs in code handling errors, especially
on memory allocation failure (MemoryError).

16
Modules/getpath.c
View File

@ -326,6 +326,7 @@ search_for_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_prefix)
if (home) {
wchar_t *delim;
wcsncpy(prefix, home, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
delim = wcschr(prefix, DELIM);
if (delim)
*delim = L'\0';
@ -335,13 +336,15 @@ search_for_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_prefix)
}
/* Check to see if argv[0] is in the build directory */
wcscpy(prefix, argv0_path);
wcsncpy(prefix, argv0_path, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
joinpath(prefix, L"Modules/Setup");
if (isfile(prefix)) {
/* Check VPATH to see if argv0_path is in the build directory. */
vpath = _Py_char2wchar(VPATH, NULL);
if (vpath != NULL) {
wcscpy(prefix, argv0_path);
wcsncpy(prefix, argv0_path, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
joinpath(prefix, vpath);
PyMem_RawFree(vpath);
joinpath(prefix, L"Lib");
@ -365,6 +368,7 @@ search_for_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_prefix)
/* Look at configure's PREFIX */
wcsncpy(prefix, _prefix, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
joinpath(prefix, lib_python);
joinpath(prefix, LANDMARK);
if (ismodule(prefix))
@ -391,6 +395,7 @@ search_for_exec_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_exec_prefix
wcsncpy(exec_prefix, delim+1, MAXPATHLEN);
else
wcsncpy(exec_prefix, home, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, lib_python);
joinpath(exec_prefix, L"lib-dynload");
return 1;
@ -399,7 +404,8 @@ search_for_exec_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_exec_prefix
/* Check to see if argv[0] is in the build directory. "pybuilddir.txt"
is written by setup.py and contains the relative path to the location
of shared library modules. */
wcscpy(exec_prefix, argv0_path);
wcsncpy(exec_prefix, argv0_path, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, L"pybuilddir.txt");
if (isfile(exec_prefix)) {
FILE *f = _Py_wfopen(exec_prefix, L"rb");
@ -420,7 +426,8 @@ search_for_exec_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_exec_prefix
Py_DECREF(decoded);
if (k >= 0) {
rel_builddir_path[k] = L'\0';
wcscpy(exec_prefix, argv0_path);
wcsncpy(exec_prefix, argv0_path, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, rel_builddir_path);
return -1;
}
@ -442,6 +449,7 @@ search_for_exec_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_exec_prefix
/* Look at configure's EXEC_PREFIX */
wcsncpy(exec_prefix, _exec_prefix, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, lib_python);
joinpath(exec_prefix, L"lib-dynload");
if (isdir(exec_prefix))

7
Python/sysmodule.c
View File

@ -1854,10 +1854,11 @@ sys_update_path(int argc, wchar_t **argv)
if (q == NULL)
argv0 = link; /* argv0 without path */
else {
/* Must make a copy */
wcscpy(argv0copy, argv0);
/* Must make a copy, argv0copy has room for 2 * MAXPATHLEN */
wcsncpy(argv0copy, argv0, MAXPATHLEN);
q = wcsrchr(argv0copy, SEP);
wcscpy(q+1, link);
wcsncpy(q+1, link, MAXPATHLEN);
q[MAXPATHLEN + 1] = L'\0';
argv0 = argv0copy;
}
}