#include <stdio.h> #include <string.h> #include <fcntl.h> #include <unistd.h> #ifdef _POSIX_SOURCE #include <signal.h> #endif #if defined(HAVE_SYSLOG) #include <sys/types.h> #include <sys/socket.h> #include <sys/un.h> #include <sys/syslog.h> #ifndef _PATH_LOG #define _PATH_LOG "/dev/log" #endif #endif long __guard[8] = {0, 0, 0, 0, 0, 0, 0, 0}; void __guard_setup (void) { int fd; if (__guard[0]!=0) return; fd = open ("/dev/urandom", 0); if (fd != -1) { ssize_t size = read (fd, (char*)&__guard, sizeof(__guard)); close (fd) ; if (size == sizeof(__guard)) return; } /* If a random generator can't be used, the protector switches the guard to the "terminator canary" */ ((char*)__guard)[0] = 0; ((char*)__guard)[1] = 0; ((char*)__guard)[2] = '\n'; ((char*)__guard)[3] = 255; } void __stack_smash_handler (char func[], int damaged) { #if defined (__GNU_LIBRARY__) extern char * __progname; #endif const char message[] = ": stack smashing attack in function "; int bufsz = 512, len; char buf[bufsz]; #if defined(HAVE_SYSLOG) int LogFile; struct sockaddr_un SyslogAddr; /* AF_UNIX address of local logger */ #endif #ifdef _POSIX_SOURCE { sigset_t mask; sigfillset(&mask); sigdelset(&mask, SIGABRT); /* Block all signal handlers */ sigprocmask(SIG_BLOCK, &mask, NULL); /* except SIGABRT */ } #endif strcpy(buf, "<2>"); len=3; /* send LOG_CRIT */ #if defined (__GNU_LIBRARY__) strncat(buf, __progname, bufsz-len-1); len = strlen(buf); #endif if (bufsz>len) {strncat(buf, message, bufsz-len-1); len = strlen(buf);} if (bufsz>len) {strncat(buf, func, bufsz-len-1); len = strlen(buf);} /* print error message */ write (STDERR_FILENO, buf+3, len-3); #if defined(HAVE_SYSLOG) if ((LogFile = socket(AF_UNIX, SOCK_DGRAM, 0)) != -1) { /* * Send "found" message to the "/dev/log" path */ SyslogAddr.sun_family = AF_UNIX; (void)strncpy(SyslogAddr.sun_path, _PATH_LOG, sizeof(SyslogAddr.sun_path) - 1); SyslogAddr.sun_path[sizeof(SyslogAddr.sun_path) - 1] = '\0'; sendto(LogFile, buf, len, 0, (struct sockaddr *)&SyslogAddr, sizeof(SyslogAddr)); } #endif #ifdef _POSIX_SOURCE { /* Make sure the default handler is associated with SIGABRT */ struct sigaction sa; memset(&sa, 0, sizeof(struct sigaction)); sigfillset(&sa.sa_mask); /* Block all signals */ sa.sa_flags = 0; sa.sa_handler = SIG_DFL; sigaction(SIGABRT, &sa, NULL); (void)kill(getpid(), SIGABRT); } #endif _exit(127); }