Check smartcard_convert_string_list for NULL string
In it has been reported that there are buggy smartcard
drivers that report a string size but fail to allocate the string
itself. This check avoids a crash with such input parameters
@@ -349,6 +349,9 @@ static char* smartcard_convert_string_list(const void* in, size_t bytes, BOOL un
if (bytes < 1)
return NULL;
+ if (in == NULL)
+ return NULL;
+
if (unicode)
{
length = (bytes / sizeof(WCHAR)) - 1;
