2 * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
17 * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT,
18 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
20 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
22 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
23 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
24 * POSSIBILITY OF SUCH DAMAGE.
26 * $OpenBSD: stack_protector.c,v 1.3 2002/12/10 08:53:42 etoh Exp $
27 * $DragonFly: src/lib/libc/sys/stack_protector.c,v 1.2 2005/01/31 22:29:46 dillon Exp $
30 #include "namespace.h"
31 #include <sys/param.h>
32 #include <sys/sysctl.h>
34 #include "un-namespace.h"
36 void __stack_smash_handler(char func[], int damaged __attribute__((unused)));
37 static void __guard_setup(void) __attribute__ ((constructor));
39 long __guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
49 if ((fd = _open ("/dev/urandom", 0)) >= 0) {
50 size = _read (fd, (char*)&__guard, sizeof(__guard));
52 if (size == sizeof(__guard))
57 * If a random generator can't be used, the protector switches the
58 * guard to the "terminator canary"
60 ((char*)__guard)[0] = 0;
61 ((char*)__guard)[1] = 0;
62 ((char*)__guard)[2] = '\n';
63 ((char*)__guard)[3] = 255;
67 __stack_smash_handler(char func[], int damaged)
69 const char message[] = "stack overflow in function %s";
72 /* this may fail on a chroot jail, though luck */
73 syslog(LOG_CRIT, message, func);
75 bzero(&sa, sizeof(struct sigaction));
76 sigemptyset(&sa.sa_mask);
78 sa.sa_handler = SIG_DFL;
79 __sys_sigaction(SIGABRT, &sa, NULL);
81 kill(getpid(), SIGABRT);