2 /* $NetBSD: stack_protector.c,v 1.4 2006/11/22 17:23:25 christos Exp $ */
3 /* $OpenBSD: stack_protector.c,v 1.10 2006/03/31 05:34:44 deraadt Exp $ */
5 * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20 * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT,
21 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
25 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
26 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
35 #include <sys/sysctl.h>
36 #include <sys/types.h>
42 extern int __sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
43 void *newp, size_t newlen);
45 long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
46 static void __guard_setup(void) __attribute__((__constructor__, __used__));
47 static void __fail(const char *);
48 void __stack_chk_fail(void);
49 void __chk_fail(void);
58 if (__stack_chk_guard[0] != 0)
64 len = sizeof(__stack_chk_guard);
65 if (__sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
66 len != sizeof(__stack_chk_guard)) {
67 /* If sysctl was unsuccessful, use the "terminator canary". */
68 ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
69 ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
70 ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
71 ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
77 __fail(const char *msg)
82 /* Immediately block all signal handlers from running code */
83 (void)sigfillset(&mask);
84 (void)sigdelset(&mask, SIGABRT);
85 (void)sigprocmask(SIG_BLOCK, &mask, NULL);
87 /* This may fail on a chroot jail... */
88 syslog(LOG_CRIT, msg);
90 (void)memset(&sa, 0, sizeof(sa));
91 (void)sigemptyset(&sa.sa_mask);
93 sa.sa_handler = SIG_DFL;
94 (void)sigaction(SIGABRT, &sa, NULL);
95 (void)kill(getpid(), SIGABRT);
100 __stack_chk_fail(void)
102 __fail("stack overflow detected; terminated");
108 __fail("buffer overflow detected; terminated");
112 __sym_compat(__stack_chk_fail_local, __stack_chk_fail, FBSD_1.0);
114 __weak_reference(__stack_chk_fail, __stack_chk_fail_local);