util.c revision 1.37 
1/*	$OpenBSD: util.c,v 1.37 2015/01/16 16:18:07 deraadt Exp $	*/
2
3/*
4 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 *
27 */
28
29#include <sys/types.h>
30#include "archdep.h"
31
32/*
33 * Stack protector dummies.
34 * Ideally, a scheme to compile these stubs from libc should be used, but
35 * this would end up dragging too much code from libc here.
36 */
37long __guard_local __dso_hidden __attribute__((section(".openbsd.randomdata")));
38
39void __stack_smash_handler(char [], int);
40
41void
42__stack_smash_handler(char func[], int damaged)
43{
44	extern const char *_dl_progname;
45	char message[100];
46
47	/* <10> indicates LOG_CRIT */
48	_dl_strlcpy(message, "<10>ld.so:", sizeof message);
49	_dl_strlcat(message, _dl_progname, sizeof message);
50	_dl_strlcat(message, "stack overflow in function ", sizeof message);
51	_dl_strlcat(message, func, sizeof message);
52
53	_dl_sendsyslog(message, _dl_strlen(message));
54	_dl_exit(127);
55}
56
57char *
58_dl_strdup(const char *orig)
59{
60	char *newstr;
61	size_t len;
62
63	len = _dl_strlen(orig)+1;
64	newstr = _dl_malloc(len);
65	if (newstr != NULL)
66		_dl_strlcpy(newstr, orig, len);
67	return (newstr);
68}
69
70void
71_dl_randombuf(void *v, size_t buflen)
72{
73	char *buf = v;
74	size_t chunk;
75
76	while (buflen != 0) {
77		if (buflen > 256)
78			chunk = 256;
79		else
80			chunk = buflen;
81		if (_dl_getentropy(buf, chunk) != 0)
82			_dl_exit(8);
83		buflen -= chunk;
84		buf += chunk;
85	}
86}
87
88u_int32_t
89_dl_random(void)
90{
91	u_int32_t rnd;
92	_dl_randombuf(&rnd, sizeof(rnd));
93	return (rnd);
94}
95