1 /* $OpenBSD: stack_protector.c,v 1.24 2017/11/29 05:13:57 guenther 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
__stack_smash_handler(const char func[],int damaged)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_BUILTIN(__stack_smash_handler);
84