/* Make sure longjmp fortification catches bad signal stacks. Copyright (C) 2013-2019 Free Software Foundation, Inc. This file is part of the GNU C Library. 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 <http://www.gnu.org/licenses/>. */ #include <setjmp.h> #include <signal.h> #include <string.h> static int do_test (void); #define TEST_FUNCTION do_test () #include "../test-skeleton.c" static char buf[SIGSTKSZ * 4]; static jmp_buf jb; static void handler (int sig) { if (sig == SIGUSR1) { if (setjmp (jb) != 0) { puts ("setjmp should not have been called"); kill (getpid (), SIGTERM); } } else if (sig == SIGABRT) { /* Yeah it worked. */ _exit (0); } } static int do_test (void) { stack_t ss; set_fortify_handler (handler); /* Create a valid signal stack and enable it. */ ss.ss_sp = buf; ss.ss_size = sizeof (buf); ss.ss_flags = 0; if (sigaltstack (&ss, NULL) < 0) { printf ("first sigaltstack failed: %m\n"); return 1; } /* Trigger the signal handler which will create a jmpbuf that points to the end of the signal stack. */ signal (SIGUSR1, handler); kill (getpid (), SIGUSR1); /* Shrink the signal stack so the jmpbuf is now invalid. We adjust the start & end to handle stacks that grow up & down. */ ss.ss_sp = buf + sizeof (buf) / 2; ss.ss_size = sizeof (buf) / 4; if (sigaltstack (&ss, NULL) < 0) { printf ("second sigaltstack failed: %m\n"); return 1; } /* This should fail. */ longjmp (jb, 1); puts ("longjmp returned and shouldn't"); return 1; }