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/* $NetBSD: stack_protector.c,v 1.9 2013/08/19 22:14:37 matt Exp $ */
/* $OpenBSD: stack_protector.c,v 1.10 2006/03/31 05:34:44 deraadt Exp $ */
/*
* Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__RCSID("$NetBSD: stack_protector.c,v 1.9 2013/08/19 22:14:37 matt Exp $");
#ifdef _LIBC
#include "namespace.h"
#endif
#include <sys/param.h>
#include <sys/sysctl.h>
#include <ssp/ssp.h>
#include <signal.h>
#include <string.h>
#include <unistd.h>
#ifdef _LIBC
#include <syslog.h>
#include "extern.h"
#else
#define __sysctl sysctl
void xprintf(const char *fmt, ...);
#include <stdlib.h>
#endif
long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
static void __fail(const char *) __attribute__((__noreturn__));
__dead void __stack_chk_fail_local(void);
void __guard_setup(void);
void __section(".text.startup")
__guard_setup(void)
{
#if !defined(__minix)
static const int mib[2] = { CTL_KERN, KERN_ARND };
size_t len;
#endif /* !defined(__minix) */
if (__stack_chk_guard[0] != 0)
return;
#if !defined(__minix)
len = sizeof(__stack_chk_guard);
if (__sysctl(mib, (u_int)__arraycount(mib), __stack_chk_guard, &len,
NULL, 0) == -1 || len != sizeof(__stack_chk_guard)) {
#endif /* !defined(__minix) */
/* If sysctl was unsuccessful, use the "terminator canary". */
((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
#if !defined(__minix)
}
#endif /* !defined(__minix) */
}
/*ARGSUSED*/
static void
__fail(const char *msg)
{
#ifdef _LIBC
struct syslog_data sdata = SYSLOG_DATA_INIT;
/* MINIX: #endif */
struct sigaction sa;
sigset_t mask;
/* Immediately block all signal handlers from running code */
(void)sigfillset(&mask);
(void)sigdelset(&mask, SIGABRT);
(void)sigprocmask(SIG_BLOCK, &mask, NULL);
/* MINIX: #ifdef _LIBC */
/* This may fail on a chroot jail... */
syslog_ss(LOG_CRIT, &sdata, "%s", msg);
#else
xprintf("%s: %s\n", getprogname(), msg);
#endif
#if defined(__minix) && defined(_LIBC)
(void)memset(&sa, 0, sizeof(sa));
(void)sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = SIG_DFL;
(void)sigaction(SIGABRT, &sa, NULL);
(void)raise(SIGABRT);
#endif /* defined(__minix) && defined(_LIBC) */
_exit(127);
}
void
__stack_chk_fail(void)
{
__fail("stack overflow detected; terminated");
}
void
__chk_fail(void)
{
__fail("buffer overflow detected; terminated");
}
void
__stack_chk_fail_local(void)
{
__stack_chk_fail();
}
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