/* * 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> #endif 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(sa)); __sigfillset(&sa.sa_mask); /* Block all signals */ if (SIG_DFL) /* if it's constant zero, it's already done */ sa.sa_handler = SIG_DFL; sigaction(SSP_SIGTYPE, &sa, NULL); } static void __cold ssp_write(int fd, const char *msg1, const char *msg2, const char *msg3) { 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