Annotation of src/lib/libc/misc/stack_protector.c, Revision 1.2.4.1
1.2.4.1 ! snj 1: /* $NetBSD: stack_protector.c,v 1.2 2008/06/03 19:22:37 ad Exp $ */
1.1 ad 2: /* $OpenBSD: stack_protector.c,v 1.10 2006/03/31 05:34:44 deraadt Exp $ */
3:
4: /*
5: * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.
6: * All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR
18: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
19: * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
20: * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT,
21: * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
22: * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
23: * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
25: * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
26: * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27: * POSSIBILITY OF SUCH DAMAGE.
28: *
29: */
30: #include <sys/cdefs.h>
1.2.4.1 ! snj 31: __RCSID("$NetBSD: stack_protector.c,v 1.2 2008/06/03 19:22:37 ad Exp $");
1.1 ad 32:
33: #ifdef _LIBC
34: #include "namespace.h"
35: #endif
36: #include <sys/param.h>
37: #include <sys/sysctl.h>
38: #include <ssp/ssp.h>
39: #include <signal.h>
40: #include <string.h>
41: #include <unistd.h>
42: #ifdef _LIBC
43: #include <syslog.h>
44: #include "extern.h"
45: #else
46: #define __sysctl sysctl
1.2 ad 47: void xprintf(const char *fmt, ...);
1.1 ad 48: #include <stdlib.h>
49: #endif
50:
51: long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};
52: static void __fail(const char *);
53: void __stack_chk_fail(void);
54: void __chk_fail(void);
55: void __stack_chk_fail_local(void);
56: void __guard_setup(void);
57:
58: void
59: __guard_setup(void)
60: {
61: int mib[2];
62: size_t len;
63:
64: if (__stack_chk_guard[0] != 0)
65: return;
66:
67: mib[0] = CTL_KERN;
68: mib[1] = KERN_ARND;
69:
70: len = sizeof(__stack_chk_guard);
71: if (__sysctl(mib, 2, __stack_chk_guard, &len, NULL, 0) == -1 ||
72: len != sizeof(__stack_chk_guard)) {
73: /* If sysctl was unsuccessful, use the "terminator canary". */
74: ((unsigned char *)(void *)__stack_chk_guard)[0] = 0;
75: ((unsigned char *)(void *)__stack_chk_guard)[1] = 0;
76: ((unsigned char *)(void *)__stack_chk_guard)[2] = '\n';
77: ((unsigned char *)(void *)__stack_chk_guard)[3] = 255;
78: }
79: }
80:
81: /*ARGSUSED*/
82: static void
83: __fail(const char *msg)
84: {
85: #ifdef _LIBC
86: struct syslog_data sdata = SYSLOG_DATA_INIT;
87: #endif
88: struct sigaction sa;
89: sigset_t mask;
90:
91: /* Immediately block all signal handlers from running code */
92: (void)sigfillset(&mask);
93: (void)sigdelset(&mask, SIGABRT);
94: (void)sigprocmask(SIG_BLOCK, &mask, NULL);
95:
96: #ifdef _LIBC
97: /* This may fail on a chroot jail... */
98: syslog_ss(LOG_CRIT, &sdata, msg);
99: #else
100: xprintf("%s: %s\n", getprogname(), msg);
101: #endif
102:
103: (void)memset(&sa, 0, sizeof(sa));
104: (void)sigemptyset(&sa.sa_mask);
105: sa.sa_flags = 0;
106: sa.sa_handler = SIG_DFL;
107: (void)sigaction(SIGABRT, &sa, NULL);
1.2.4.1 ! snj 108: (void)raise(SIGABRT);
1.1 ad 109: _exit(127);
110: }
111:
112: void
113: __stack_chk_fail(void)
114: {
115: __fail("stack overflow detected; terminated");
116: }
117:
118: void
119: __chk_fail(void)
120: {
121: __fail("buffer overflow detected; terminated");
122: }
123:
124: void
125: __stack_chk_fail_local(void)
126: {
127: __stack_chk_fail();
128: }
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