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/*
* Distributed under the terms of the GNU Lesser General Public License
* $Header: $
*
* This is a modified version of Hiroaki Etoh's stack smashing routines
* implemented for glibc.
*
* The following people have contributed input to this code.
* Ned Ludd - <solar[@]gentoo.org>
* Alexander Gabert - <pappy[@]gentoo.org>
* The PaX Team - <pageexec[@]freemail.hu>
* Peter S. Mazinger - <ps.m[@]gmx.net>
* Yoann Vandoorselaere - <yoann[@]prelude-ids.org>
* Robert Connolly - <robert[@]linuxfromscratch.org>
* Cory Visi <cory[@]visi.name>
* Mike Frysinger <vapier[@]gentoo.org>
*/
#if defined __SSP__ || defined __SSP_ALL__
#error "file must not be compiled with stack protection enabled on it. Use -fno-stack-protector"
#endif
#ifdef __PROPOLICE_BLOCK_SEGV__
# define SSP_SIGTYPE SIGSEGV
#else
# define SSP_SIGTYPE SIGABRT
#endif
#include <string.h>
#include <unistd.h>
#include <signal.h>
#if defined __UCLIBC_HAS_SYSLOG__
#include <sys/syslog.h>
libc_hidden_proto(openlog)
libc_hidden_proto(syslog)
libc_hidden_proto(closelog)
#endif
/* libc_hidden_proto(sigaction) */
libc_hidden_proto(sigfillset)
libc_hidden_proto(sigdelset)
/* libc_hidden_proto(sigprocmask) */
/* libc_hidden_proto(write) */
libc_hidden_proto(kill)
/* libc_hidden_proto(getpid) */
/* libc_hidden_proto(_exit) */
static void block_signals(void)
{
struct sigaction sa;
sigset_t mask;
sigfillset(&mask);
sigdelset(&mask, SSP_SIGTYPE); /* Block all signal handlers */
sigprocmask(SIG_BLOCK, &mask, NULL); /* except SSP_SIGTYPE */
/* Make the default handler associated with the signal handler */
memset(&sa, 0, sizeof(struct sigaction));
sigfillset(&sa.sa_mask); /* Block all signals */
sa.sa_flags = 0;
sa.sa_handler = SIG_DFL;
sigaction(SSP_SIGTYPE, &sa, NULL);
}
static void ssp_write(int fd, const char *msg1, const char *msg2, const char *msg3) __cold
{
write(fd, msg1, strlen(msg1));
write(fd, msg2, strlen(msg2));
write(fd, msg3, strlen(msg3));
write(fd, "()\n", 3);
#if defined __UCLIBC_HAS_SYSLOG__
openlog("ssp", LOG_CONS | LOG_PID, LOG_USER);
syslog(LOG_INFO, "%s%s%s()", msg1, msg2, msg3);
closelog();
#endif
}
static attribute_noreturn void terminate(void)
{
(void) kill(getpid(), SSP_SIGTYPE);
_exit(127);
}
void __stack_smash_handler(char func[], int damaged __attribute__ ((unused))) attribute_noreturn __cold;
void __stack_smash_handler(char func[], int damaged)
{
static const char message[] = ": stack smashing attack in function ";
block_signals();
ssp_write(STDERR_FILENO, __uclibc_progname, message, func);
/* The loop is added only to keep gcc happy. */
while(1)
terminate();
}
void __stack_chk_fail(void) attribute_noreturn __cold;
void __stack_chk_fail(void)
{
static const char msg1[] = "stack smashing detected: ";
static const char msg3[] = " terminated";
block_signals();
ssp_write(STDERR_FILENO, msg1, __uclibc_progname, msg3);
/* The loop is added only to keep gcc happy. */
while(1)
terminate();
}
#if 0
void __chk_fail(void) attribute_noreturn;
void __chk_fail(void)
{
static const char msg1[] = "buffer overflow detected: ";
static const char msg3[] = " terminated";
block_signals();
ssp_write(STDERR_FILENO, msg1, __uclibc_progname, msg3);
/* The loop is added only to keep gcc happy. */
while(1)
terminate();
}
#endif
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