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[3.6] bpo-30730: Prevent environment variables injection in subprocess on Windows. (GH-2325) (#2360)

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Prevent passing other invalid environment variables and command arguments..
(cherry picked from commit d174d24a5d)
This commit is contained in:
Serhiy Storchaka 2017-06-23 20:17:38 +03:00 • committed by GitHub
parent 1b7474dedc
commit e7135751b8
5 changed files with 72 additions and 9 deletions
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26
Modules/_winapi.c
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@ -744,6 +744,20 @@ getenvironment(PyObject* environment)
"environment can only contain strings");
goto error;
}
if (PyUnicode_FindChar(key, '\0', 0, PyUnicode_GET_LENGTH(key), 1) != -1 ||
PyUnicode_FindChar(value, '\0', 0, PyUnicode_GET_LENGTH(value), 1) != -1)
{
PyErr_SetString(PyExc_ValueError, "embedded null character");
goto error;
}
/* Search from index 1 because on Windows starting '=' is allowed for
defining hidden environment variables. */
if (PyUnicode_GET_LENGTH(key) == 0 ||
PyUnicode_FindChar(key, '=', 1, PyUnicode_GET_LENGTH(key), 1) != -1)
{
PyErr_SetString(PyExc_ValueError, "illegal environment variable name");
goto error;
}
if (totalsize > PY_SSIZE_T_MAX - PyUnicode_GET_LENGTH(key) - 1) {
PyErr_SetString(PyExc_OverflowError, "environment too long");
goto error;
@ -830,7 +844,8 @@ _winapi_CreateProcess_impl(PyObject *module, Py_UNICODE *application_name,
PROCESS_INFORMATION pi;
STARTUPINFOW si;
PyObject* environment;
wchar_t *wenvironment;
const wchar_t *wenvironment;
Py_ssize_t wenvironment_size;
ZeroMemory(&si, sizeof(si));
si.cb = sizeof(si);
@ -846,12 +861,13 @@ _winapi_CreateProcess_impl(PyObject *module, Py_UNICODE *application_name,
if (env_mapping != Py_None) {
environment = getenvironment(env_mapping);
if (! environment)
if (environment == NULL) {
return NULL;
}
/* contains embedded null characters */
wenvironment = PyUnicode_AsUnicode(environment);
if (wenvironment == NULL)
{
Py_XDECREF(environment);
if (wenvironment == NULL) {
Py_DECREF(environment);
return NULL;
}
}