mirror of
https://github.com/omar-polo/gmid.git
synced 2024-10-01 23:11:14 +02:00
f9ab77a898
gmid (like all other daemons that want to do privsep crypto) has a very close relationship with libtls and need to stay in sync with it. OpenBSD' libtls was recently changed to use OpenSSL' EC_KEY_METHOD instead of the older ECDSA_METHOD, on the gmid side we have to do the same otherwise failures happens at runtime. In a similar manner, privsep crypto is silently broken in the current libretls (next version should fix it.) The proper solution would be to complete the signer APIs so that applications don't need to dive into the library' internals, but that's a mid-term goal, for the immediate bundling the 'little' libtls is the lesser evil. The configure script has gained a new (undocumented for the time being) flag `--with-libtls=bundled|system' to control which libtls to use. It defaults to `bundled' except for OpenBSD where it uses the `system' one. Note that OpenBSD versions before 7.3 (inclusive) ought to use --with-libtls=bundled too since they still do ECDSA_METHOD.
253 lines
6.0 KiB
C
253 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 "../config.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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/*
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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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# 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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