util.c revision 1.42 
1/*	$OpenBSD: util.c,v 1.42 2016/08/05 15:42:05 tedu 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 <syslog.h>
31#include "archdep.h"
32#include "resolve.h"
33
34/*
35 * Stack protector dummies.
36 * Ideally, a scheme to compile these stubs from libc should be used, but
37 * this would end up dragging too much code from libc here.
38 */
39long __guard_local __dso_hidden __attribute__((section(".openbsd.randomdata")));
40
41void __stack_smash_handler(char [], int);
42
43void
44__stack_smash_handler(char func[], int damaged)
45{
46	char message[256];
47
48	/* <10> indicates LOG_CRIT */
49	_dl_strlcpy(message, "<10>ld.so:", sizeof message);
50	_dl_strlcat(message, __progname, sizeof message);
51	if (_dl_strlen(message) > sizeof(message)/2)
52		_dl_strlcpy(message + sizeof(message)/2, "...",
53		    sizeof(message) - sizeof(message)/2);
54	_dl_strlcat(message, "stack overflow in function ", sizeof message);
55	_dl_strlcat(message, func, sizeof message);
56
57	_dl_sendsyslog(message, _dl_strlen(message), LOG_CONS);
58	_dl_exit(127);
59}
60
61char *
62_dl_strdup(const char *orig)
63{
64	char *newstr;
65	size_t len;
66
67	len = _dl_strlen(orig)+1;
68	newstr = _dl_malloc(len);
69	if (newstr != NULL)
70		_dl_strlcpy(newstr, orig, len);
71	return (newstr);
72}
73
74void
75_dl_randombuf(void *v, size_t buflen)
76{
77	static char bytes[256];
78	static u_int reserve;
79	char *buf = v;
80	size_t chunk;
81
82	while (buflen != 0) {
83		if (reserve == 0) {
84			if (_dl_getentropy(bytes, sizeof(bytes)) != 0)
85				_dl_exit(8);
86			reserve = sizeof(bytes);
87		}
88		if (buflen > reserve)
89			chunk = reserve;
90		else
91			chunk = buflen;
92#if 0
93		memcpy(buf, bytes + reserve - chunk, chunk);
94		memset(bytes + reserve - chunk, 0, chunk);
95#else
96		{
97			char *d = buf;
98			char *s = bytes + reserve - chunk;
99			u_int l;
100			for (l = chunk; l > 0; l--, s++, d++) {
101				*d = *s;
102				*s = 0;
103			}
104		}
105#endif
106		reserve -= chunk;
107		buflen -= chunk;
108		buf += chunk;
109	}
110}
111
112u_int32_t
113_dl_random(void)
114{
115	u_int32_t rnd;
116	_dl_randombuf(&rnd, sizeof(rnd));
117	return (rnd);
118}
119