freebsd-dev/usr.bin/rlogin/des_rw.c

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1994-05-27 12:33:43 +00:00
/*-
* Copyright (c) 1989, 1993
* The Regents of the University of California. 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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 lint
static char sccsid[] = "@(#)des_rw.c 8.1 (Berkeley) 6/6/93";
#endif /* not lint */
#ifdef CRYPT
#ifdef KERBEROS
#include <sys/param.h>
#include <kerberosIV/des.h>
#include <kerberosIV/krb.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
static unsigned char des_inbuf[10240], storage[10240], *store_ptr;
static bit_64 *key;
static u_char *key_schedule;
/* XXX these should be in a kerberos include file */
int krb_net_read __P((int, char *, int));
#ifdef notdef
/* XXX too hard to make this work */
int des_pcbc_encrypt __P((des_cblock *, des_cblock *, long,
des_key_schedule, des_cblock *, int));
#endif
/*
* NB: These routines will not function properly if NBIO
* is set
*/
/*
* des_set_key
*
* Set des encryption/decryption key for use by the des_read and
* des_write routines
*
* The inkey parameter is actually the DES initial vector,
* and the insched is the DES Key unwrapped for faster decryption
*/
void
des_set_key(inkey, insched)
bit_64 *inkey;
u_char *insched;
{
key = inkey;
key_schedule = insched;
}
void
des_clear_key()
{
bzero((char *) key, sizeof(C_Block));
bzero((char *) key_schedule, sizeof(Key_schedule));
}
int
des_read(fd, buf, len)
int fd;
register char *buf;
int len;
{
int nreturned = 0;
long net_len, rd_len;
int nstored = 0;
if (nstored >= len) {
(void) bcopy(store_ptr, buf, len);
store_ptr += len;
nstored -= len;
return(len);
} else if (nstored) {
(void) bcopy(store_ptr, buf, nstored);
nreturned += nstored;
buf += nstored;
len -= nstored;
nstored = 0;
}
if (krb_net_read(fd, (char *)&net_len, sizeof(net_len)) !=
sizeof(net_len)) {
/* XXX can't read enough, pipe
must have closed */
return(0);
}
net_len = ntohl(net_len);
if (net_len <= 0 || net_len > sizeof(des_inbuf)) {
/* preposterous length; assume out-of-sync; only
recourse is to close connection, so return 0 */
return(0);
}
/* the writer tells us how much real data we are getting, but
we need to read the pad bytes (8-byte boundary) */
rd_len = roundup(net_len, 8);
if (krb_net_read(fd, (char *)des_inbuf, rd_len) != rd_len) {
/* pipe must have closed, return 0 */
return(0);
}
(void) des_pcbc_encrypt(des_inbuf, /* inbuf */
storage, /* outbuf */
net_len, /* length */
key_schedule, /* DES key */
key, /* IV */
DECRYPT); /* direction */
if(net_len < 8)
store_ptr = storage + 8 - net_len;
else
store_ptr = storage;
nstored = net_len;
if (nstored > len) {
(void) bcopy(store_ptr, buf, len);
nreturned += len;
store_ptr += len;
nstored -= len;
} else {
(void) bcopy(store_ptr, buf, nstored);
nreturned += nstored;
nstored = 0;
}
return(nreturned);
}
static unsigned char des_outbuf[10240]; /* > longest write */
int
des_write(fd, buf, len)
int fd;
char *buf;
int len;
{
static int seeded = 0;
static char garbage_buf[8];
long net_len, garbage;
if(len < 8) {
if(!seeded) {
seeded = 1;
srandom((int) time((long *)0));
}
garbage = random();
/* insert random garbage */
(void) bcopy(&garbage, garbage_buf, MIN(sizeof(long),8));
/* this "right-justifies" the data in the buffer */
(void) bcopy(buf, garbage_buf + 8 - len, len);
}
/* pcbc_encrypt outputs in 8-byte (64 bit) increments */
(void) des_pcbc_encrypt((len < 8) ? garbage_buf : buf,
des_outbuf,
(len < 8) ? 8 : len,
key_schedule, /* DES key */
key, /* IV */
ENCRYPT);
/* tell the other end the real amount, but send an 8-byte padded
packet */
net_len = htonl(len);
(void) write(fd, &net_len, sizeof(net_len));
(void) write(fd, des_outbuf, roundup(len,8));
return(len);
}
#endif /* KERBEROS */
#endif /* CRYPT */