b7c4ed65cc
Use a constant array for the MIB. Newer LLVM decided that mib[] warranted stack protections, with the obvious crash after the setup was done. As a positive side effect, code size shrinks a bit. I'm not sure why this hasn't bitten us yes, but it is certainly possible and there are no real drawbacks to this change anyway. Submitted by: pfg Obtained from: NetBSD MFC after: 1 week
118 lines
3.5 KiB
C
118 lines
3.5 KiB
C
/* $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 <errno.h>
|
|
#include <link.h>
|
|
#include <signal.h>
|
|
#include <string.h>
|
|
#include <syslog.h>
|
|
#include <unistd.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__));
|
|
static void __fail(const char *);
|
|
void __stack_chk_fail(void);
|
|
void __chk_fail(void);
|
|
|
|
/*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;
|
|
}
|
|
}
|
|
|
|
/*ARGSUSED*/
|
|
static void
|
|
__fail(const char *msg)
|
|
{
|
|
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);
|
|
|
|
/* This may fail on a chroot jail... */
|
|
syslog(LOG_CRIT, "%s", msg);
|
|
|
|
(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)kill(getpid(), SIGABRT);
|
|
_exit(127);
|
|
}
|
|
|
|
void
|
|
__stack_chk_fail(void)
|
|
{
|
|
__fail("stack overflow detected; terminated");
|
|
}
|
|
|
|
void
|
|
__chk_fail(void)
|
|
{
|
|
__fail("buffer overflow detected; terminated");
|
|
}
|
|
|
|
#ifndef PIC
|
|
__weak_reference(__stack_chk_fail, __stack_chk_fail_local);
|
|
#endif
|