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8 changes: 8 additions & 0 deletions .gitignore
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*~
*.o
/Makefile
/condhashconsts.h
/generate
/nodehashconsts.h
/varhashconsts.h
/omake
14 changes: 14 additions & 0 deletions arc4random-local.h
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/* public domain */

#ifndef _ARC4RANDOM_LOCAL_H
#define _ARC4RANDOM_LOCAL_H

#ifdef __linux__
void arc4random_stir(void);
void arc4random_addrandom(unsigned char *dat, int datlen);
uint32_t arc4random(void);
void arc4random_buf(void *buf, size_t n);
uint32_t arc4random_uniform(uint32_t upper_bound);
#endif

#endif
212 changes: 212 additions & 0 deletions arc4random.c
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/* $OpenBSD: arc4random.c,v 1.53 2015/09/10 18:53:50 bcook Exp $ */

/*
* Copyright (c) 1996, David Mazieres <dm@uun.org>
* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
* Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
* Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
* Copyright (c) 2015, Guillem Jover <guillem@hadrons.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/*
* ChaCha based random number generator for OpenBSD.
*/

#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/time.h>

#define KEYSTREAM_ONLY
#include "chacha_private.h"

#define minimum(a, b) ((a) < (b) ? (a) : (b))

#if defined(__GNUC__) || defined(__clang__) || defined(_MSC_VER)
#define inline __inline
#else /* __GNUC__ || __clang__ || _MSC_VER */
#define inline
#endif /* !__GNUC__ && !__clang__ && !_MSC_VER */

#define KEYSZ 32
#define IVSZ 8
#define BLOCKSZ 64
#define RSBUFSZ (16*BLOCKSZ)

/* Marked MAP_INHERIT_ZERO, so zero'd out in fork children. */
static struct _rs {
size_t rs_have; /* valid bytes at end of rs_buf */
size_t rs_count; /* bytes till reseed */
} *rs;

/* Maybe be preserved in fork children, if _rs_allocate() decides. */
static struct _rsx {
chacha_ctx rs_chacha; /* chacha context for random keystream */
unsigned char rs_buf[RSBUFSZ]; /* keystream blocks */
} *rsx;

static inline int _rs_allocate(struct _rs **, struct _rsx **);
static inline void _rs_forkdetect(void);
#include "arc4random.h"

static inline void
_rs_init(unsigned char *buf, size_t n)
{
if (n < KEYSZ + IVSZ)
return;

if (rs == NULL) {
if (_rs_allocate(&rs, &rsx) == -1)
abort();
}

chacha_keysetup(&rsx->rs_chacha, buf, KEYSZ * 8, 0);
chacha_ivsetup(&rsx->rs_chacha, buf + KEYSZ);
}

static inline void
_rs_rekey(unsigned char *dat, size_t datlen)
{
#ifndef KEYSTREAM_ONLY
memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));
#endif
/* fill rs_buf with the keystream */
chacha_encrypt_bytes(&rsx->rs_chacha, rsx->rs_buf,
rsx->rs_buf, sizeof(rsx->rs_buf));
/* mix in optional user provided data */
if (dat) {
size_t i, m;

m = minimum(datlen, KEYSZ + IVSZ);
for (i = 0; i < m; i++)
rsx->rs_buf[i] ^= dat[i];
}
/* immediately reinit for backtracking resistance */
_rs_init(rsx->rs_buf, KEYSZ + IVSZ);
memset(rsx->rs_buf, 0, KEYSZ + IVSZ);
rs->rs_have = sizeof(rsx->rs_buf) - KEYSZ - IVSZ;
}

static void
_rs_stir(void)
{
unsigned char rnd[KEYSZ + IVSZ];

if (getentropy(rnd, sizeof rnd) == -1)
_getentropy_fail();

if (!rs)
_rs_init(rnd, sizeof(rnd));
else
_rs_rekey(rnd, sizeof(rnd));
explicit_bzero(rnd, sizeof(rnd)); /* discard source seed */

/* invalidate rs_buf */
rs->rs_have = 0;
memset(rsx->rs_buf, 0, sizeof(rsx->rs_buf));

rs->rs_count = 1600000;
}

static inline void
_rs_stir_if_needed(size_t len)
{
_rs_forkdetect();
if (!rs || rs->rs_count <= len)
_rs_stir();
if (rs->rs_count <= len)
rs->rs_count = 0;
else
rs->rs_count -= len;
}

static inline void
_rs_random_buf(void *_buf, size_t n)
{
unsigned char *buf = (unsigned char *)_buf;
unsigned char *keystream;
size_t m;

_rs_stir_if_needed(n);
while (n > 0) {
if (rs->rs_have > 0) {
m = minimum(n, rs->rs_have);
keystream = rsx->rs_buf + sizeof(rsx->rs_buf)
- rs->rs_have;
memcpy(buf, keystream, m);
memset(keystream, 0, m);
buf += m;
n -= m;
rs->rs_have -= m;
}
if (rs->rs_have == 0)
_rs_rekey(NULL, 0);
}
}

static inline void
_rs_random_u32(uint32_t *val)
{
unsigned char *keystream;

_rs_stir_if_needed(sizeof(*val));
if (rs->rs_have < sizeof(*val))
_rs_rekey(NULL, 0);
keystream = rsx->rs_buf + sizeof(rsx->rs_buf) - rs->rs_have;
memcpy(val, keystream, sizeof(*val));
memset(keystream, 0, sizeof(*val));
rs->rs_have -= sizeof(*val);
}

void
arc4random_stir(void)
{
_ARC4_LOCK();
_rs_stir();
_ARC4_UNLOCK();
}

void
arc4random_addrandom(unsigned char *dat, int datlen)
{
_ARC4_LOCK();
_rs_stir_if_needed(datlen);
_rs_rekey(dat, datlen);
_ARC4_UNLOCK();
}

uint32_t
arc4random(void)
{
uint32_t val;

_ARC4_LOCK();
_rs_random_u32(&val);
_ARC4_UNLOCK();
return val;
}

void
arc4random_buf(void *buf, size_t n)
{
_ARC4_LOCK();
_rs_random_buf(buf, n);
_ARC4_UNLOCK();
}
45 changes: 45 additions & 0 deletions arc4random.h
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/*
* Copyright © 2015 Guillem Jover <guillem@hadrons.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef LIBBSD_ARC4RANDOM_H
#define LIBBSD_ARC4RANDOM_H

#include <sys/param.h>

int
getentropy(void *buf, size_t len);

#if defined(__OpenBSD__)
#include "arc4random_openbsd.h"
#elif defined(__linux__)
#include "arc4random_linux.h"
#elif defined(_WIN32)
#include "arc4random_win.h"
#else
#include "arc4random_unix.h"
#endif

#endif
88 changes: 88 additions & 0 deletions arc4random_linux.h
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/* $OpenBSD: arc4random_linux.h,v 1.11 2016/06/30 12:19:51 bcook Exp $ */

/*
* Copyright (c) 1996, David Mazieres <dm@uun.org>
* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
* Copyright (c) 2013, Markus Friedl <markus@openbsd.org>
* Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

/*
* Stub functions for portability.
*/

#include <sys/mman.h>

#include <pthread.h>
#include <signal.h>

static pthread_mutex_t arc4random_mtx = PTHREAD_MUTEX_INITIALIZER;
#define _ARC4_LOCK() pthread_mutex_lock(&arc4random_mtx)
#define _ARC4_UNLOCK() pthread_mutex_unlock(&arc4random_mtx)

#ifdef HAVE___REGISTER_ATFORK
extern void *__dso_handle;
extern int __register_atfork(void (*)(void), void(*)(void), void (*)(void), void *);
#define _ARC4_ATFORK(f) __register_atfork(NULL, NULL, (f), __dso_handle)
#else
#define _ARC4_ATFORK(f) pthread_atfork(NULL, NULL, (f))
#endif

static inline void
_getentropy_fail(void)
{
raise(SIGKILL);
}

static volatile sig_atomic_t _rs_forked;

static inline void
_rs_forkhandler(void)
{
_rs_forked = 1;
}

static inline void
_rs_forkdetect(void)
{
static pid_t _rs_pid = 0;
pid_t pid = getpid();

/* XXX unusual calls to clone() can bypass checks */
if (_rs_pid == 0 || _rs_pid == 1 || _rs_pid != pid || _rs_forked) {
_rs_pid = pid;
_rs_forked = 0;
if (rs)
memset(rs, 0, sizeof(*rs));
}
}

static inline int
_rs_allocate(struct _rs **rsp, struct _rsx **rsxp)
{
if ((*rsp = mmap(NULL, sizeof(**rsp), PROT_READ|PROT_WRITE,
MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED)
return (-1);

if ((*rsxp = mmap(NULL, sizeof(**rsxp), PROT_READ|PROT_WRITE,
MAP_ANON|MAP_PRIVATE, -1, 0)) == MAP_FAILED) {
munmap(*rsp, sizeof(**rsp));
*rsp = NULL;
return (-1);
}

_ARC4_ATFORK(_rs_forkhandler);
return (0);
}
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