1 | /*␊ |
2 | * Copyright (c) 2002 Hiroaki Etoh, Federico G. Schwindt, and Miodrag Vallat.␊ |
3 | * All rights reserved.␊ |
4 | *␊ |
5 | * Redistribution and use in source and binary forms, with or without␊ |
6 | * modification, are permitted provided that the following conditions␊ |
7 | * are met:␊ |
8 | * 1. Redistributions of source code must retain the above copyright␊ |
9 | * notice, this list of conditions and the following disclaimer.␊ |
10 | * 2. Redistributions in binary form must reproduce the above copyright␊ |
11 | * notice, this list of conditions and the following disclaimer in the␊ |
12 | * documentation and/or other materials provided with the distribution.␊ |
13 | *␊ |
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY EXPRESS OR␊ |
15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED␊ |
16 | * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE␊ |
17 | * DISCLAIMED. IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT,␊ |
18 | * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES␊ |
19 | * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR␊ |
20 | * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)␊ |
21 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,␊ |
22 | * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN␊ |
23 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE␊ |
24 | * POSSIBILITY OF SUCH DAMAGE.␊ |
25 | *␊ |
26 | */␊ |
27 | #include <stdio.h>␊ |
28 | #include <stdlib.h>␊ |
29 | ␊ |
30 | #include <sys/types.h>␊ |
31 | #include <sys/cdefs.h>␊ |
32 | #include <Availability.h>␊ |
33 | ␊ |
34 | #include <_types.h>␊ |
35 | extern void arc4random_buf(void *_buf, size_t n);␊ |
36 | extern void stop(const char *format, ...);␊ |
37 | extern void halt(void);␊ |
38 | ␊ |
39 | #define __arraycount(__x) (sizeof(__x) / sizeof(__x[0]))␊ |
40 | ␊ |
41 | long __stack_chk_guard[8] = {0, 0, 0, 0, 0, 0, 0, 0};␊ |
42 | ␊ |
43 | //__private_extern__ void __guard_setup(void) /*__attribute__ ((visibility ("hidden")))*/;␊ |
44 | void __guard_setup(void) __attribute__((constructor));␊ |
45 | ␊ |
46 | void __stack_chk_fail(void);␊ |
47 | ␊ |
48 | ␊ |
49 | void␊ |
50 | __guard_setup(void)␊ |
51 | {␊ |
52 | ␉if (__stack_chk_guard[0]!=0) return;␊ |
53 | ␉␊ |
54 | ␉size_t i;␊ |
55 | ␉long guard[__arraycount(__stack_chk_guard)];␉␊ |
56 | ␉␊ |
57 | ␉arc4random_buf(guard, sizeof(guard));␊ |
58 | ␉for (i = 0; i < __arraycount(guard); i++)␊ |
59 | ␉␉__stack_chk_guard[i] = guard[i];␊ |
60 | ␉␊ |
61 | ␉if (__stack_chk_guard[0]!=0 && *__stack_chk_guard != 0) return;␊ |
62 | ␉␊ |
63 | ␉/* If a random generator can't be used, the protector switches the guard␊ |
64 | to the "terminator canary" */␊ |
65 | ␉((char*)__stack_chk_guard)[0] = 0; ((char*)__stack_chk_guard)[1] = 0;␊ |
66 | ␉((char*)__stack_chk_guard)[2] = '\n'; ((char*)__stack_chk_guard)[3] = 255;␉␊ |
67 | ␉␊ |
68 | }␊ |
69 | ␊ |
70 | void␊ |
71 | __stack_chk_fail()␊ |
72 | {␊ |
73 | #ifndef BOOT1␊ |
74 | ␉printf("stack overflow");␊ |
75 | #endif␊ |
76 | ␉halt();␊ |
77 | }␊ |
78 | |