archive_random.c revision 370535 
1/*-
2 * Copyright (c) 2014 Michihiro NAKAJIMA
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 AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "archive_platform.h"
27__FBSDID("$FreeBSD: stable/11/contrib/libarchive/libarchive/archive_random.c 370535 2021-09-10 08:34:36Z git2svn $");
28
29#ifdef HAVE_STDLIB_H
30#include <stdlib.h>
31#endif
32
33#if !defined(HAVE_ARC4RANDOM_BUF) && (!defined(_WIN32) || defined(__CYGWIN__))
34
35#ifdef HAVE_FCNTL
36#include <fcntl.h>
37#endif
38#ifdef HAVE_LIMITS_H
39#include <limits.h>
40#endif
41#ifdef HAVE_UNISTD_H
42#include <unistd.h>
43#endif
44#ifdef HAVE_SYS_TYPES_H
45#include <sys/types.h>
46#endif
47#ifdef HAVE_SYS_TIME_H
48#include <sys/time.h>
49#endif
50#ifdef HAVE_PTHREAD_H
51#include <pthread.h>
52#endif
53
54static void arc4random_buf(void *, size_t);
55
56#endif /* HAVE_ARC4RANDOM_BUF */
57
58#include "archive.h"
59#include "archive_random_private.h"
60
61#if defined(HAVE_WINCRYPT_H) && !defined(__CYGWIN__)
62#include <wincrypt.h>
63#endif
64
65#ifndef O_CLOEXEC
66#define O_CLOEXEC	0
67#endif
68
69/*
70 * Random number generator function.
71 * This simply calls arc4random_buf function if the platform provides it.
72 */
73
74int
75archive_random(void *buf, size_t nbytes)
76{
77#if defined(_WIN32) && !defined(__CYGWIN__)
78	HCRYPTPROV hProv;
79	BOOL success;
80
81	success = CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL,
82	    CRYPT_VERIFYCONTEXT);
83	if (!success && GetLastError() == (DWORD)NTE_BAD_KEYSET) {
84		success = CryptAcquireContext(&hProv, NULL, NULL,
85		    PROV_RSA_FULL, CRYPT_NEWKEYSET);
86	}
87	if (success) {
88		success = CryptGenRandom(hProv, (DWORD)nbytes, (BYTE*)buf);
89		CryptReleaseContext(hProv, 0);
90		if (success)
91			return ARCHIVE_OK;
92	}
93	/* TODO: Does this case really happen? */
94	return ARCHIVE_FAILED;
95#else
96	arc4random_buf(buf, nbytes);
97	return ARCHIVE_OK;
98#endif
99}
100
101#if !defined(HAVE_ARC4RANDOM_BUF) && (!defined(_WIN32) || defined(__CYGWIN__))
102
103/*	$OpenBSD: arc4random.c,v 1.24 2013/06/11 16:59:50 deraadt Exp $	*/
104/*
105 * Copyright (c) 1996, David Mazieres <dm@uun.org>
106 * Copyright (c) 2008, Damien Miller <djm@openbsd.org>
107 *
108 * Permission to use, copy, modify, and distribute this software for any
109 * purpose with or without fee is hereby granted, provided that the above
110 * copyright notice and this permission notice appear in all copies.
111 *
112 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
113 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
114 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
115 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
116 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
117 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
118 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
119 */
120
121/*
122 * Arc4 random number generator for OpenBSD.
123 *
124 * This code is derived from section 17.1 of Applied Cryptography,
125 * second edition, which describes a stream cipher allegedly
126 * compatible with RSA Labs "RC4" cipher (the actual description of
127 * which is a trade secret).  The same algorithm is used as a stream
128 * cipher called "arcfour" in Tatu Ylonen's ssh package.
129 *
130 * RC4 is a registered trademark of RSA Laboratories.
131 */
132
133#ifdef __GNUC__
134#define inline __inline
135#else				/* !__GNUC__ */
136#define inline
137#endif				/* !__GNUC__ */
138
139struct arc4_stream {
140	uint8_t i;
141	uint8_t j;
142	uint8_t s[256];
143};
144
145#define	RANDOMDEV	"/dev/urandom"
146#define	KEYSIZE		128
147#ifdef HAVE_PTHREAD_H
148static pthread_mutex_t	arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
149#define	_ARC4_LOCK()	pthread_mutex_lock(&arc4random_mtx);
150#define	_ARC4_UNLOCK()  pthread_mutex_unlock(&arc4random_mtx);
151#else
152#define	_ARC4_LOCK()
153#define	_ARC4_UNLOCK()
154#endif
155
156static int rs_initialized;
157static struct arc4_stream rs;
158static pid_t arc4_stir_pid;
159static int arc4_count;
160
161static inline uint8_t arc4_getbyte(void);
162static void arc4_stir(void);
163
164static inline void
165arc4_init(void)
166{
167	int     n;
168
169	for (n = 0; n < 256; n++)
170		rs.s[n] = n;
171	rs.i = 0;
172	rs.j = 0;
173}
174
175static inline void
176arc4_addrandom(uint8_t *dat, int datlen)
177{
178	int     n;
179	uint8_t si;
180
181	rs.i--;
182	for (n = 0; n < 256; n++) {
183		rs.i = (rs.i + 1);
184		si = rs.s[rs.i];
185		rs.j = (rs.j + si + dat[n % datlen]);
186		rs.s[rs.i] = rs.s[rs.j];
187		rs.s[rs.j] = si;
188	}
189	rs.j = rs.i;
190}
191
192static void
193arc4_stir(void)
194{
195	int done, fd, i;
196	struct {
197		struct timeval	tv;
198		pid_t		pid;
199		uint8_t		rnd[KEYSIZE];
200	} rdat;
201
202	if (!rs_initialized) {
203		arc4_init();
204		rs_initialized = 1;
205	}
206	done = 0;
207	fd = open(RANDOMDEV, O_RDONLY | O_CLOEXEC, 0);
208	if (fd >= 0) {
209		if (read(fd, &rdat, KEYSIZE) == KEYSIZE)
210			done = 1;
211		(void)close(fd);
212	}
213	if (!done) {
214		(void)gettimeofday(&rdat.tv, NULL);
215		rdat.pid = getpid();
216		/* We'll just take whatever was on the stack too... */
217	}
218
219	arc4_addrandom((uint8_t *)&rdat, KEYSIZE);
220
221	/*
222	 * Discard early keystream, as per recommendations in:
223	 * "(Not So) Random Shuffles of RC4" by Ilya Mironov.
224	 * As per the Network Operations Division, cryptographic requirements
225	 * published on wikileaks on March 2017.
226	 */
227
228	for (i = 0; i < 3072; i++)
229		(void)arc4_getbyte();
230	arc4_count = 1600000;
231}
232
233static void
234arc4_stir_if_needed(void)
235{
236	pid_t pid = getpid();
237
238	if (arc4_count <= 0 || !rs_initialized || arc4_stir_pid != pid) {
239		arc4_stir_pid = pid;
240		arc4_stir();
241	}
242}
243
244static inline uint8_t
245arc4_getbyte(void)
246{
247	uint8_t si, sj;
248
249	rs.i = (rs.i + 1);
250	si = rs.s[rs.i];
251	rs.j = (rs.j + si);
252	sj = rs.s[rs.j];
253	rs.s[rs.i] = sj;
254	rs.s[rs.j] = si;
255	return (rs.s[(si + sj) & 0xff]);
256}
257
258static void
259arc4random_buf(void *_buf, size_t n)
260{
261	uint8_t *buf = (uint8_t *)_buf;
262	_ARC4_LOCK();
263	arc4_stir_if_needed();
264	while (n--) {
265		if (--arc4_count <= 0)
266			arc4_stir();
267		buf[n] = arc4_getbyte();
268	}
269	_ARC4_UNLOCK();
270}
271
272#endif /* !HAVE_ARC4RANDOM_BUF */
273