/* Test for vfprintf nargs allocation overflow (BZ #13656). Copyright (C) 2012-2016 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Kees Cook , 2012. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #include #include #include #include #include #include #include static int format_failed (const char *fmt, const char *expected) { char output[80]; printf ("%s : ", fmt); memset (output, 0, sizeof output); /* Having sprintf itself detect a failure is good. */ if (sprintf (output, fmt, 1, 2, 3, "test") > 0 && strcmp (output, expected) != 0) { printf ("FAIL (output '%s' != expected '%s')\n", output, expected); return 1; } puts ("ok"); return 0; } static int do_test (void) { int rc = 0; char buf[64]; /* Regular positionals work. */ if (format_failed ("%1$d", "1") != 0) rc = 1; /* Regular width positionals work. */ if (format_failed ("%1$*2$d", " 1") != 0) rc = 1; /* Positional arguments are constructed via read_int, so nargs can only overflow on 32-bit systems. On 64-bit systems, it will attempt to allocate a giant amount of memory and possibly crash, which is the expected situation. Since the 64-bit behavior is arch-specific, only test this on 32-bit systems. */ if (sizeof (long int) == 4) { sprintf (buf, "%%1$d %%%" PRIdPTR "$d", (intptr_t) (UINT32_MAX / sizeof (int))); if (format_failed (buf, "1 %$d") != 0) rc = 1; } return rc; } #define TEST_FUNCTION do_test () #include "../test-skeleton.c"