openssh/openbsd-compat/bsd-arc4random.c
Damien Miller b0fb6872ed - deraadt@cvs.openbsd.org 2006/03/19 18:51:18
[atomicio.c auth-bsdauth.c auth-chall.c auth-krb5.c auth-options.c]
     [auth-pam.c auth-passwd.c auth-rh-rsa.c auth-rhosts.c auth-rsa.c]
     [auth-shadow.c auth-skey.c auth.c auth1.c auth2-chall.c]
     [auth2-hostbased.c auth2-kbdint.c auth2-none.c auth2-passwd.c]
     [auth2-pubkey.c auth2.c authfd.c authfile.c bufaux.c buffer.c]
     [canohost.c channels.c cipher-3des1.c cipher-acss.c cipher-aes.c]
     [cipher-bf1.c cipher-ctr.c cipher.c cleanup.c clientloop.c compat.c]
     [compress.c deattack.c dh.c dispatch.c dns.c entropy.c fatal.c]
     [groupaccess.c hostfile.c includes.h kex.c kexdh.c kexdhc.c]
     [kexdhs.c kexgex.c kexgexc.c kexgexs.c key.c log.c loginrec.c]
     [loginrec.h logintest.c mac.c match.c md-sha256.c md5crypt.c misc.c]
     [monitor.c monitor_fdpass.c monitor_mm.c monitor_wrap.c msg.c]
     [nchan.c packet.c progressmeter.c readconf.c readpass.c rsa.c]
     [scard.c scp.c servconf.c serverloop.c session.c sftp-client.c]
     [sftp-common.c sftp-glob.c sftp-server.c sftp.c ssh-add.c]
     [ssh-agent.c ssh-dss.c ssh-keygen.c ssh-keyscan.c ssh-keysign.c]
     [ssh-rand-helper.c ssh-rsa.c ssh.c sshconnect.c sshconnect1.c]
     [sshconnect2.c sshd.c sshlogin.c sshpty.c sshtty.c ttymodes.c]
     [uidswap.c uuencode.c xmalloc.c openbsd-compat/bsd-arc4random.c]
     [openbsd-compat/bsd-closefrom.c openbsd-compat/bsd-cygwin_util.c]
     [openbsd-compat/bsd-getpeereid.c openbsd-compat/bsd-misc.c]
     [openbsd-compat/bsd-nextstep.c openbsd-compat/bsd-snprintf.c]
     [openbsd-compat/bsd-waitpid.c openbsd-compat/fake-rfc2553.c]
     RCSID() can die
2006-03-26 00:03:21 +11:00

79 lines
2.0 KiB
C

/*
* Copyright (c) 1999,2000,2004 Damien Miller <djm@mindrot.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 "includes.h"
#include "log.h"
#ifndef HAVE_ARC4RANDOM
#include <openssl/rand.h>
#include <openssl/rc4.h>
#include <openssl/err.h>
/* Size of key to use */
#define SEED_SIZE 20
/* Number of bytes to reseed after */
#define REKEY_BYTES (1 << 24)
static int rc4_ready = 0;
static RC4_KEY rc4;
unsigned int
arc4random(void)
{
unsigned int r = 0;
static int first_time = 1;
if (rc4_ready <= 0) {
if (first_time)
seed_rng();
first_time = 0;
arc4random_stir();
}
RC4(&rc4, sizeof(r), (unsigned char *)&r, (unsigned char *)&r);
rc4_ready -= sizeof(r);
return(r);
}
void
arc4random_stir(void)
{
unsigned char rand_buf[SEED_SIZE];
int i;
memset(&rc4, 0, sizeof(rc4));
if (RAND_bytes(rand_buf, sizeof(rand_buf)) <= 0)
fatal("Couldn't obtain random bytes (error %ld)",
ERR_get_error());
RC4_set_key(&rc4, sizeof(rand_buf), rand_buf);
/*
* Discard early keystream, as per recommendations in:
* http://www.wisdom.weizmann.ac.il/~itsik/RC4/Papers/Rc4_ksa.ps
*/
for(i = 0; i <= 256; i += sizeof(rand_buf))
RC4(&rc4, sizeof(rand_buf), rand_buf, rand_buf);
memset(rand_buf, 0, sizeof(rand_buf));
rc4_ready = REKEY_BYTES;
}
#endif /* !HAVE_ARC4RANDOM */