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/*
* Copyright (c) 1996, David Mazieres <dm@uun.org>
* Copyright (c) 2008, Damien Miller <djm@openbsd.org>
* Copyright (c) 2013, Markus Friedl <markus@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.
*/
#include "../config.h"
#ifndef SSH_RANDOM_DEV
# define SSH_RANDOM_DEV "/dev/urandom"
#endif /* SSH_RANDOM_DEV */
#include <sys/types.h>
#ifdef HAVE_SYS_RANDOM_H
# include <sys/random.h>
#endif
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#ifdef WITH_OPENSSL
#include <openssl/rand.h>
#include <openssl/err.h>
#endif
#include "log.h"
int _ssh_compat_getentropy(void *, size_t);
static int
seed_from_prngd(unsigned char *buf, size_t bytes)
{
return -1;
}
int
_ssh_compat_getentropy(void *s, size_t len)
{
#if defined(WITH_OPENSSL) && defined(OPENSSL_PRNG_ONLY)
if (RAND_bytes(s, len) <= 0)
fatal("Couldn't obtain random bytes (error 0x%lx)",
(unsigned long)ERR_get_error());
#else
int fd, save_errno;
ssize_t r;
size_t o = 0;
#ifdef WITH_OPENSSL
if (RAND_bytes(s, len) == 1)
return 0;
#endif
#ifdef HAVE_GETENTROPY
if ((r = getentropy(s, len)) == 0)
return 0;
#endif /* HAVE_GETENTROPY */
#ifdef HAVE_GETRANDOM
if ((r = getrandom(s, len, 0)) > 0 && (size_t)r == len)
return 0;
#endif /* HAVE_GETRANDOM */
if ((fd = open(SSH_RANDOM_DEV, O_RDONLY)) == -1) {
save_errno = errno;
/* Try egd/prngd before giving up. */
if (seed_from_prngd(s, len) == 0)
return 0;
fatal("Couldn't open %s: %s", SSH_RANDOM_DEV,
strerror(save_errno));
}
while (o < len) {
r = read(fd, (u_char *)s + o, len - o);
if (r < 0) {
if (errno == EAGAIN || errno == EINTR ||
errno == EWOULDBLOCK)
continue;
fatal("read %s: %s", SSH_RANDOM_DEV, strerror(errno));
}
o += r;
}
close(fd);
#endif /* WITH_OPENSSL */
return 0;
}
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