1 /* $OpenBSD: stack_protector.c,v 1.23 2016/03/21 22:41:28 bluhm Exp $ */ 2 3 /* 4 * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 18 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 19 * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, 20 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 21 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 22 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 24 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 25 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 * 28 */ 29 30 #include <signal.h> 31 #include <stdlib.h> 32 #include <string.h> 33 #include <syslog.h> 34 #include <unistd.h> 35 36 /* 37 * Note: test below is for PIC not __PIC__. This code must only be included 38 * in the shared library and not in libc.a, but __PIC__ is set for libc.a 39 * objects where PIE is supported 40 * 41 * XXX would this work? #if defined(__PIC__) && !defined(__PIE__) 42 * XXX any archs which are always PIC (like mips64) but don't have PIE? 43 */ 44 #ifdef PIC 45 #include <../csu/os-note-elf.h> 46 47 long __guard_local __dso_hidden __attribute__((section(".openbsd.randomdata"))); 48 #endif /* PIC */ 49 50 void 51 __stack_smash_handler(const char func[], int damaged) 52 { 53 struct sigaction sa; 54 sigset_t mask; 55 char buf[1024]; 56 57 /* Immediately block all signal handlers from running code */ 58 sigfillset(&mask); 59 sigdelset(&mask, SIGABRT); 60 sigprocmask(SIG_SETMASK, &mask, NULL); 61 62 /* <10> is LOG_CRIT */ 63 strlcpy(buf, "<10>", sizeof buf); 64 65 /* Make sure progname does not fill the whole buffer */ 66 strlcat(buf, __progname, sizeof(buf) / 2 ); 67 68 strlcat(buf, ": stack overflow in function ", sizeof buf); 69 strlcat(buf, func, sizeof buf); 70 71 sendsyslog(buf, strlen(buf), LOG_CONS); 72 73 memset(&sa, 0, sizeof(sa)); 74 sigemptyset(&sa.sa_mask); 75 sa.sa_flags = 0; 76 sa.sa_handler = SIG_DFL; 77 sigaction(SIGABRT, &sa, NULL); 78 79 thrkill(0, SIGABRT, NULL); 80 81 _exit(127); 82 } 83 DEF_STRONG(__stack_smash_handler); 84