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lib/libc/secure/stack_protector.c
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/* $NetBSD: stack_protector.c,v 1.4 2006/11/22 17:23:25 christos 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> | |||||
__FBSDID("$FreeBSD$"); | |||||
#include <sys/param.h> | |||||
#include <sys/sysctl.h> | |||||
#include <sys/types.h> | |||||
#include <secure/security.h> | |||||
#include <link.h> | |||||
#include "libc_private.h" | |||||
extern int __sysctl(const int *name, u_int namelen, void *oldp, | |||||
size_t *oldlenp, void *newp, size_t newlen); | |||||
long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; | |||||
static void __guard_setup(void) __attribute__((__constructor__, __used__)); | |||||
void __stack_chk_fail(void) __dead2; | |||||
/*LINTED used*/ | |||||
static void | |||||
__guard_setup(void) | |||||
{ | |||||
static const int mib[2] = { CTL_KERN, KERN_ARND }; | |||||
size_t len; | |||||
int error; | |||||
if (__stack_chk_guard[0] != 0) | |||||
return; | |||||
error = _elf_aux_info(AT_CANARY, __stack_chk_guard, | |||||
sizeof(__stack_chk_guard)); | |||||
if (error == 0 && __stack_chk_guard[0] != 0) | |||||
return; | |||||
len = sizeof(__stack_chk_guard); | |||||
if (__sysctl(mib, nitems(mib), __stack_chk_guard, &len, NULL, 0) == | |||||
-1 || len != sizeof(__stack_chk_guard)) { | |||||
/* 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; | |||||
} | |||||
} | |||||
void | |||||
__stack_chk_fail(void) | |||||
{ | |||||
__secure_fail("stack overflow detected; terminated"); | |||||
} | |||||
void | |||||
__chk_fail(void) | |||||
{ | |||||
__secure_fail("buffer overflow detected; terminated"); | |||||
} | |||||
#ifndef PIC | |||||
__weak_reference(__stack_chk_fail, __stack_chk_fail_local); | |||||
#endif |