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/*
* Copyright (c) 2001 Damien Miller. All rights reserved.
*
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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.
*/
#include "includes.h"
#define RANDOM_SEED_SIZE 48
#ifdef WITH_OPENSSL
#include <sys/types.h>
#include <errno.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <openssl/rand.h>
#include <openssl/crypto.h>
#include <openssl/err.h>
#include "openbsd-compat/openssl-compat.h"
#include "ssh.h"
#include "misc.h"
#include "xmalloc.h"
#include "atomicio.h"
#include "pathnames.h"
#include "log.h"
#include "sshbuf.h"
#include "ssherr.h"
/*
* Portable OpenSSH PRNG seeding:
* If OpenSSL has not "internally seeded" itself (e.g. pulled data from
* /dev/random), then collect RANDOM_SEED_SIZE bytes of randomness from
* PRNGd.
*/
#ifndef OPENSSL_PRNG_ONLY
void
rexec_send_rng_seed(struct sshbuf *m)
{
u_char buf[RANDOM_SEED_SIZE];
size_t len = sizeof(buf);
int r;
if (RAND_bytes(buf, sizeof(buf)) <= 0) {
error("Couldn't obtain random bytes (error %ld)",
ERR_get_error());
len = 0;
}
if ((r = sshbuf_put_string(m, buf, len)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
explicit_bzero(buf, sizeof(buf));
}
void
rexec_recv_rng_seed(struct sshbuf *m)
{
const u_char *buf = NULL;
size_t len = 0;
int r;
if ((r = sshbuf_get_string_direct(m, &buf, &len)) != 0)
fatal("%s: buffer error: %s", __func__, ssh_err(r));
debug3("rexec_recv_rng_seed: seeding rng with %lu bytes",
(unsigned long)len);
RAND_add(buf, len, len);
}
#endif /* OPENSSL_PRNG_ONLY */
void
seed_rng(void)
{
unsigned char buf[RANDOM_SEED_SIZE];
/* Initialise libcrypto */
ssh_libcrypto_init();
if (!ssh_compatible_openssl(OPENSSL_VERSION_NUMBER,
OpenSSL_version_num()))
fatal("OpenSSL version mismatch. Built against %lx, you "
"have %lx", (u_long)OPENSSL_VERSION_NUMBER,
OpenSSL_version_num());
#ifndef OPENSSL_PRNG_ONLY
if (RAND_status() == 1)
debug3("RNG is ready, skipping seeding");
else {
if (seed_from_prngd(buf, sizeof(buf)) == -1)
fatal("Could not obtain seed from PRNGd");
RAND_add(buf, sizeof(buf), sizeof(buf));
}
#endif /* OPENSSL_PRNG_ONLY */
if (RAND_status() != 1)
fatal("PRNG is not seeded");
/* Ensure arc4random() is primed */
arc4random_buf(buf, sizeof(buf));
explicit_bzero(buf, sizeof(buf));
}
#else /* WITH_OPENSSL */
#include <stdlib.h>
#include <string.h>
/* Actual initialisation is handled in arc4random() */
void
seed_rng(void)
{
unsigned char buf[RANDOM_SEED_SIZE];
/* Ensure arc4random() is primed */
arc4random_buf(buf, sizeof(buf));
explicit_bzero(buf, sizeof(buf));
}
#endif /* WITH_OPENSSL */
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