f374ba41f5
Release notes are available at https://www.openssh.com/txt/release-9.2 OpenSSH 9.2 contains fixes for two security problems and a memory safety problem. The memory safety problem is not believed to be exploitable. These fixes have already been committed to OpenSSH 9.1 in FreeBSD. Some other notable items from the release notes: * ssh(1): add a new EnableEscapeCommandline ssh_config(5) option that controls whether the client-side ~C escape sequence that provides a command-line is available. Among other things, the ~C command-line could be used to add additional port-forwards at runtime. * sshd(8): add support for channel inactivity timeouts via a new sshd_config(5) ChannelTimeout directive. This allows channels that have not seen traffic in a configurable interval to be automatically closed. Different timeouts may be applied to session, X11, agent and TCP forwarding channels. * sshd(8): add a sshd_config UnusedConnectionTimeout option to terminate client connections that have no open channels for a length of time. This complements the ChannelTimeout option above. * sshd(8): add a -V (version) option to sshd like the ssh client has. * scp(1), sftp(1): add a -X option to both scp(1) and sftp(1) to allow control over some SFTP protocol parameters: the copy buffer length and the number of in-flight requests, both of which are used during upload/download. Previously these could be controlled in sftp(1) only. This makes them available in both SFTP protocol clients using the same option character sequence. * ssh-keyscan(1): allow scanning of complete CIDR address ranges, e.g. "ssh-keyscan 192.168.0.0/24". If a CIDR range is passed, then it will be expanded to all possible addresses in the range including the all-0s and all-1s addresses. bz#976 * ssh(1): support dynamic remote port forwarding in escape command-line's -R processing. bz#3499 MFC after: 1 week Sponsored by: The FreeBSD Foundation
255 lines
6.0 KiB
C
255 lines
6.0 KiB
C
/* $OpenBSD: arc4random.c,v 1.58 2022/07/31 13:41:45 tb Exp $ */
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/*
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* Copyright (c) 1996, David Mazieres <dm@uun.org>
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* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
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* Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
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* Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* ChaCha based random number generator for OpenBSD.
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*/
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/* OPENBSD ORIGINAL: lib/libc/crypt/arc4random.c */
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#include "includes.h"
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#include <sys/types.h>
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#include <fcntl.h>
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#include <limits.h>
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#include <signal.h>
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#ifdef HAVE_STDINT_H
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#include <stdint.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <sys/time.h>
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#ifndef HAVE_ARC4RANDOM
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/*
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* Always use the getentropy implementation from bsd-getentropy.c, which
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* will call a native getentropy if available then fall back as required.
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* We use a different name so that OpenSSL cannot call the wrong getentropy.
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*/
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int _ssh_compat_getentropy(void *, size_t);
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#ifdef getentropy
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# undef getentropy
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#endif
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#define getentropy(x, y) (_ssh_compat_getentropy((x), (y)))
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#include "log.h"
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#define KEYSTREAM_ONLY
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#include "chacha_private.h"
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#define minimum(a, b) ((a) < (b) ? (a) : (b))
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#if defined(__GNUC__) || defined(_MSC_VER)
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#define inline __inline
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#else /* __GNUC__ || _MSC_VER */
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#define inline
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#endif /* !__GNUC__ && !_MSC_VER */
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#define KEYSZ 32
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#define IVSZ 8
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#define BLOCKSZ 64
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#define RSBUFSZ (16*BLOCKSZ)
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#define REKEY_BASE (1024*1024) /* NB. should be a power of 2 */
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/* Marked MAP_INHERIT_ZERO, so zero'd out in fork children. */
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static struct _rs {
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size_t rs_have; /* valid bytes at end of rs_buf */
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size_t rs_count; /* bytes till reseed */
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} *rs;
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/* Maybe be preserved in fork children, if _rs_allocate() decides. */
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static struct _rsx {
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chacha_ctx rs_chacha; /* chacha context for random keystream */
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u_char rs_buf[RSBUFSZ]; /* keystream blocks */
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} *rsx;
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static inline int _rs_allocate(struct _rs **, struct _rsx **);
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static inline void _rs_forkdetect(void);
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#include "arc4random.h"
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static inline void _rs_rekey(u_char *dat, size_t datlen);
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static inline void
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_rs_init(u_char *buf, size_t n)
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{
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if (n < KEYSZ + IVSZ)
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return;
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if (rs == NULL) {
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if (_rs_allocate(&rs, &rsx) == -1)
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_exit(1);
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}
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chacha_keysetup(&rsx->rs_chacha, buf, KEYSZ * 8);
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chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ);
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}
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static void
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_rs_stir(void)
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{
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u_char rnd[KEYSZ + IVSZ];
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uint32_t rekey_fuzz = 0;
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if (getentropy(rnd, sizeof rnd) == -1)
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_getentropy_fail();
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if (!rs)
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_rs_init(rnd, sizeof(rnd));
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else
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_rs_rekey(rnd, sizeof(rnd));
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explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */
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/* invalidate rs_buf */
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rs->rs_have = 0;
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memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
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/* rekey interval should not be predictable */
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chacha_encrypt_bytes(&rsx->rs_chacha, (uint8_t *)&rekey_fuzz,
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(uint8_t *)&rekey_fuzz, sizeof(rekey_fuzz));
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rs->rs_count = REKEY_BASE + (rekey_fuzz % REKEY_BASE);
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}
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static inline void
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_rs_stir_if_needed(size_t len)
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{
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_rs_forkdetect();
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if (!rs || rs->rs_count <= len)
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_rs_stir();
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if (rs->rs_count <= len)
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rs->rs_count = 0;
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else
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rs->rs_count -= len;
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}
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static inline void
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_rs_rekey(u_char *dat, size_t datlen)
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{
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#ifndef KEYSTREAM_ONLY
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memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
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#endif
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/* fill rs_buf with the keystream */
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chacha_encrypt_bytes(&rsx->rs_chacha, rsx->rs_buf,
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rsx->rs_buf, sizeof(rsx->rs_buf));
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/* mix in optional user provided data */
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if (dat) {
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size_t i, m;
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m = minimum(datlen, KEYSZ + IVSZ);
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for (i = 0; i < m; i++)
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rsx->rs_buf[i] ^= dat[i];
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}
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/* immediately reinit for backtracking resistance */
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_rs_init(rsx->rs_buf, KEYSZ + IVSZ);
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memset(rsx->rs_buf, 0, KEYSZ + IVSZ);
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rs->rs_have = sizeof(rsx->rs_buf) - KEYSZ - IVSZ;
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}
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static inline void
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_rs_random_buf(void *_buf, size_t n)
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{
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u_char *buf = (u_char *)_buf;
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u_char *keystream;
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size_t m;
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_rs_stir_if_needed(n);
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while (n > 0) {
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if (rs->rs_have > 0) {
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m = minimum(n, rs->rs_have);
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keystream = rsx->rs_buf + sizeof(rsx->rs_buf)
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- rs->rs_have;
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memcpy(buf, keystream, m);
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memset(keystream, 0, m);
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buf += m;
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n -= m;
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rs->rs_have -= m;
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}
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if (rs->rs_have == 0)
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_rs_rekey(NULL, 0);
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}
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}
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static inline void
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_rs_random_u32(uint32_t *val)
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{
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u_char *keystream;
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_rs_stir_if_needed(sizeof(*val));
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if (rs->rs_have < sizeof(*val))
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_rs_rekey(NULL, 0);
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keystream = rsx->rs_buf + sizeof(rsx->rs_buf) - rs->rs_have;
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memcpy(val, keystream, sizeof(*val));
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memset(keystream, 0, sizeof(*val));
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rs->rs_have -= sizeof(*val);
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}
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uint32_t
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arc4random(void)
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{
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uint32_t val;
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_ARC4_LOCK();
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_rs_random_u32(&val);
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_ARC4_UNLOCK();
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return val;
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}
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DEF_WEAK(arc4random);
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/*
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* If we are providing arc4random, then we can provide a more efficient
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* arc4random_buf().
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*/
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# ifndef HAVE_ARC4RANDOM_BUF
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void
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arc4random_buf(void *buf, size_t n)
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{
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_ARC4_LOCK();
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_rs_random_buf(buf, n);
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_ARC4_UNLOCK();
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}
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DEF_WEAK(arc4random_buf);
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# endif /* !HAVE_ARC4RANDOM_BUF */
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#endif /* !HAVE_ARC4RANDOM */
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/* arc4random_buf() that uses platform arc4random() */
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#if !defined(HAVE_ARC4RANDOM_BUF) && defined(HAVE_ARC4RANDOM)
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void
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arc4random_buf(void *_buf, size_t n)
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{
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size_t i;
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u_int32_t r = 0;
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char *buf = (char *)_buf;
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for (i = 0; i < n; i++) {
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if (i % 4 == 0)
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r = arc4random();
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buf[i] = r & 0xff;
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r >>= 8;
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}
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explicit_bzero(&r, sizeof(r));
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}
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#endif /* !defined(HAVE_ARC4RANDOM_BUF) && defined(HAVE_ARC4RANDOM) */
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