Net2/usr/src/lib/libtelnet/krb_des.c
/*-
* Copyright (c) 1991 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[] = "@(#)krb_des.c 5.1 (Berkeley) 2/28/91";
#endif /* not lint */
/*
* Copyright (C) 1990 by the Massachusetts Institute of Technology
*
* Export of this software from the United States of America is assumed
* to require a specific license from the United States Government.
* It is the responsibility of any person or organization contemplating
* export to obtain such a license before exporting.
*
* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
* distribute this software and its documentation for any purpose and
* without fee is hereby granted, provided that the above copyright
* notice appear in all copies and that both that copyright notice and
* this permission notice appear in supporting documentation, and that
* the name of M.I.T. not be used in advertising or publicity pertaining
* to distribution of the software without specific, written prior
* permission. M.I.T. makes no representations about the suitability of
* this software for any purpose. It is provided "as is" without express
* or implied warranty.
*/
#if defined(AUTHENTICATE) && defined(ENCRYPT) && defined(KRBDES_ENCRYPT)
#include <arpa/telnet.h>
#include <stdio.h>
#ifdef __STDC__
#include <stdlib.h>
#endif
#include "encrypt.h"
#include "key-proto.h"
#include "misc-proto.h"
extern encrypt_debug_mode;
static Block krbdes_key = { 0 };
static Schedule krbdes_sched = { 0 };
static Block input_feed = { 0 };
static Block output_feed = { 0 };
static Block temp_feed = { 0 };
static unsigned char str_feed[64] = { IAC, SB, TELOPT_ENCRYPT,
ENCRYPT_IS,
ENCTYPE_KRBDES, };
void
krbdes_init(server)
int server;
{
bzero((void *)krbdes_key, sizeof(Block));
bzero((void *)krbdes_sched, sizeof(Schedule));
bzero((void *)input_feed, sizeof(Block));
bzero((void *)output_feed, sizeof(Block));
}
#define KRBDES_FEED_INIT 1
#define KRBDES_FEED_VRFY 2
#define KRBDES_FEED_FAIL 3
#define KRBDES_FEED_OK 4
#define KRBDES_FEED_VRFY_FAIL 5
/*
* Returns:
* -1: some error. Negotiation is done, encryption not ready.
* 0: Successful, initial negotiation all done.
* 1: successful, negotiation not done yet.
* 2: Not yet. Other things (like getting the key from
* Kerberos) have to happen before we can continue.
*/
#define NOT_YET 2
#define IN_PROGRESS 1
#define SUCCESS 0
#define FAILED -1
int state[2] = { NOT_YET, NOT_YET };
#define ENCRYPT_STATE 0
#define DECRYPT_STATE 1
/*
* This is where we keep track of the fact that there has been a
* call to krbdes_start(), but we haven't gotten a valid key from
* kerberos, so that when (if) it does come in, we can continue with
* the initial encryption startup.
*/
static int need_start;
int
krbdes_start(dir, server)
int dir;
int server;
{
Block b;
int x;
unsigned char *p;
switch (dir) {
case DIR_DECRYPT:
/*
* This is simply a request to have the other side
* start output (our input). He will negotiate a
* feed so we need not look for it.
*/
if (!VALIDKEY(krbdes_key))
return(state[DECRYPT_STATE]);
if (state[DECRYPT_STATE] == NOT_YET)
state[DECRYPT_STATE] = IN_PROGRESS;
return(state[DECRYPT_STATE]);
case DIR_ENCRYPT:
if (!VALIDKEY(krbdes_key)) {
need_start = 1;
return(state[ENCRYPT_STATE]);
}
if (state[ENCRYPT_STATE] == IN_PROGRESS)
return(IN_PROGRESS);
if (VALIDKEY(output_feed))
return(SUCCESS);
if (encrypt_debug_mode)
printf("Creating new feed\r\n");
/*
* Create a random feed and send it over encrypted.
* The other side will decrypt it, xor in 'KRBDES'
* and then recrypt it and send it back.
*/
des_new_random_key(temp_feed);
des_ecb_encrypt(temp_feed, b, krbdes_sched, 1);
str_feed[3] = ENCRYPT_IS;
p = str_feed + 5;
*p++ = KRBDES_FEED_INIT;
for (x = 0; x < sizeof(Block); ++x) {
if ((*p++ = b[x]) == IAC)
*p++ = IAC;
}
*p++ = IAC;
*p++ = SE;
printsub('>', &str_feed[2], p - &str_feed[2]);
net_write(str_feed, p - str_feed);
temp_feed[0] ^= 'K';
temp_feed[1] ^= 'R';
temp_feed[2] ^= 'B';
temp_feed[3] ^= 'D';
temp_feed[4] ^= 'E';
temp_feed[5] ^= 'S';
state[ENCRYPT_STATE] = IN_PROGRESS;
return(IN_PROGRESS);
default:
return(FAILED);
}
}
/*
* Returns:
* -1: some error. Negotiation is done, encryption not ready.
* 0: Successful, initial negotiation all done.
* 1: successful, negotiation not done yet.
*/
int
krbdes_is(data, cnt)
unsigned char *data;
int cnt;
{
int x;
unsigned char *p;
unsigned char *why = 0;
Block b;
if (cnt-- < 1) {
why = (unsigned char *)"Bad IS suboption";
goto failure;
}
switch (*data++) {
case KRBDES_FEED_INIT:
if (cnt != sizeof(Block)) {
if (encrypt_debug_mode)
printf("Use Feed failed on size\r\n");
why = (unsigned char *)"Bad block size";
goto failure;
}
if (!VALIDKEY(krbdes_key)) {
if (encrypt_debug_mode)
printf("Use Feed failed on key\r\n");
why = (unsigned char *)"Invalid key";
goto failure;
}
if (encrypt_debug_mode)
printf("Have a Use Feed\r\n");
bcopy((void *)data, (void *)b, sizeof(Block));
des_ecb_encrypt(b, input_feed, krbdes_sched, 0);
input_feed[0] ^= 'K';
input_feed[1] ^= 'R';
input_feed[2] ^= 'B';
input_feed[3] ^= 'D';
input_feed[4] ^= 'E';
input_feed[5] ^= 'S';
des_ecb_encrypt(input_feed, b, krbdes_sched, 1);
str_feed[3] = ENCRYPT_REPLY;
p = str_feed + 5;
*p++ = KRBDES_FEED_VRFY;
for (x = 0; x < sizeof(Block); ++x) {
if ((*p++ = b[x]) == IAC)
*p++ = IAC;
}
*p++ = IAC;
*p++ = SE;
printsub('>', &str_feed[2], p - &str_feed[2]);
net_write(str_feed, p - str_feed);
if (encrypt_debug_mode)
printf("Initializing Decrypt stream\r\n");
key_stream_init(krbdes_key, input_feed, DIR_DECRYPT);
state[DECRYPT_STATE] = IN_PROGRESS;
return(IN_PROGRESS);
case KRBDES_FEED_OK:
state[DECRYPT_STATE] = SUCCESS;
return(SUCCESS);
case KRBDES_FEED_FAIL:
state[DECRYPT_STATE] = FAILED;
return(FAILED);
default:
if (encrypt_debug_mode) {
printf("Unknown option type: %d\r\n", data[-1]);
printd(data, cnt);
printf("\r\n");
}
why = (unsigned char *)"Unknown sub-suboption";
failure:
/*
* We failed. Send an empty KRBDES_FEED_VRFY option
* to the other side so it will know that things
* failed.
*/
str_feed[3] = ENCRYPT_REPLY;
p = str_feed + 5;
*p++ = KRBDES_FEED_VRFY_FAIL;
if (why) {
while (*why) {
if ((*p++ = *why++) == IAC)
*p++ = IAC;
}
}
*p++ = IAC;
*p++ = SE;
printsub('>', &str_feed[2], p - &str_feed[2]);
net_write(str_feed, p - str_feed);
state[DECRYPT_STATE] = FAILED;
return(FAILED);
}
}
/*
* Returns:
* -1: some error. Negotiation is done, encryption not ready.
* 0: Successful, initial negotiation all done.
* 1: successful, negotiation not done yet.
*/
int
krbdes_reply(data, cnt)
unsigned char *data;
int cnt;
{
int x;
unsigned char *p;
unsigned char *why = 0;
Block b;
if (cnt-- < 1) {
why = (unsigned char *)"Bad REPLY suboption";
goto failure;
}
switch (*data++) {
case KRBDES_FEED_VRFY:
if (cnt != sizeof(Block)) {
if (encrypt_debug_mode)
printf("Have Feed failed on size\r\n");
why = (unsigned char *)"Bad block size";
goto failure;
}
if (!VALIDKEY(krbdes_key)) {
if (encrypt_debug_mode)
printf("Have Feed failed on key\r\n");
why = (unsigned char *)"Invalid key";
goto failure;
}
if (encrypt_debug_mode)
printf("Have a Test Feed\r\n");
bcopy((void *)data, (void *)b, sizeof(Block));
des_ecb_encrypt(b, output_feed, krbdes_sched, 0);
if (!SAMEKEY(output_feed, temp_feed)) {
if (encrypt_debug_mode)
printf("Have Feed failed on challange\r\n");
bzero((void *)output_feed, sizeof(Block));
why = (unsigned char*)"Challange decrypt failed";
goto failure;
}
if (encrypt_debug_mode)
printf("Initializing Encrypt stream\r\n");
key_stream_init(krbdes_key, output_feed, DIR_ENCRYPT);
str_feed[3] = ENCRYPT_IS;
p = str_feed + 5;
*p++ = KRBDES_FEED_OK;
*p++ = IAC;
*p++ = SE;
printsub('>', &str_feed[2], p - &str_feed[2]);
net_write(str_feed, p - str_feed);
state[ENCRYPT_STATE] = SUCCESS;
return(SUCCESS);
default:
if (encrypt_debug_mode) {
printf("Unknown option type: %d\r\n", data[-1]);
printd(data, cnt);
printf("\r\n");
}
why = (unsigned char *)"Unknown sub-suboption";
failure:
str_feed[3] = ENCRYPT_IS;
p = str_feed + 5;
*p++ = KRBDES_FEED_FAIL;
if (why) {
while (*why) {
if ((*p++ = *why++) == IAC)
*p++ = IAC;
}
}
*p++ = IAC;
*p++ = SE;
printsub('>', &str_feed[2], p - &str_feed[2]);
net_write(str_feed, p - str_feed);
state[ENCRYPT_STATE] = FAILED;
return(FAILED);
}
}
void
krbdes_encrypt(s, c)
unsigned char *s;
int c;
{
while (c-- > 0) {
*s = key_stream(DIR_ENCRYPT, *s);
++s;
}
}
int
krbdes_decrypt(c)
int c;
{
return(key_stream(DIR_DECRYPT, c));
#ifdef ndef
if (c == -1) {
++use;
return(0);
}
if (use) {
use = 0;
} else {
last = key_stream(DIR_DECRYPT, c);
}
return(last ^ c);
#endif
}
void
krbdes_session(key, server)
Session_Key *key;
int server;
{
static once = 1;
if (!key || key->type != SK_DES) {
if (encrypt_debug_mode)
printf("Can't set krbdes's session key (%d != %d)\r\n",
key ? key->type : -1, SK_DES);
return;
}
bcopy((void *)key->data, (void *)krbdes_key, sizeof(Block));
if (once) {
des_set_random_generator_seed(krbdes_key);
once = 0;
}
des_key_sched(krbdes_key, krbdes_sched);
/*
* Now look to see if krbdes_start() was was waiting for
* the key to show up. If so, go ahead an call it now
* that we have the key.
*/
if (need_start) {
krbdes_start(DIR_ENCRYPT, server);
need_start = 0;
}
}
void
krbdes_printsub(data, cnt, buf, buflen)
unsigned char *data, *buf;
int cnt, buflen;
{
char lbuf[32];
register int i;
char *cp;
buf[buflen-1] = '\0'; /* make sure it's NULL terminated */
buflen -= 1;
switch(data[2]) {
case KRBDES_FEED_OK:
cp = "FEED_OK";
goto common1;
case KRBDES_FEED_FAIL:
cp = "FEED_FAIL";
common1:
for (; (buflen > 0) && (*buf = *cp++); buf++)
buflen--;
if (cnt > 3) {
if (buflen <= 0)
break;
*buf++ = ' ';
if (--buflen <= 0)
break;
*buf++ = '"';
for (i = 3; i < cnt && buflen > 0; i++, buflen--)
*buf++ = data[i];
if (buflen <= 0)
break;
*buf++ = '"';
--buflen;
}
if (buflen <= 0)
break;
*buf++ = '\0';
break;
case KRBDES_FEED_INIT:
cp = "FEED_INIT ";
goto common2;
case KRBDES_FEED_VRFY:
cp = "FEED_VRFY ";
goto common2;
default:
sprintf(lbuf, " %d (unknown)", data[2]);
cp = lbuf;
common2:
for (; (buflen > 0) && (*buf = *cp++); buf++)
buflen--;
for (i = 3; i < cnt; i++) {
sprintf(lbuf, " %d", data[i]);
for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++)
buflen--;
}
break;
}
}
static Block stream_output[2];
static Block stream_feed[2];
static Schedule stream_sched[2];
static int stream_index[2];
void
key_stream_init(key, seed, dir)
Block key;
Block seed;
int dir;
{
des_key_sched(key, stream_sched[--dir]);
bcopy((void *)seed, (void *)stream_output[dir], sizeof(Block));
stream_index[dir] = sizeof(Block);
}
unsigned char
key_stream(dir, data)
int dir;
int data; /* data de/encrypting */
{
int index;
if (data == -1) {
/* Backpeddle */
if (stream_index[--dir])
--stream_index[dir];
return(0);
}
if ((index = stream_index[--dir]++) == sizeof(Block)) {
Block b;
des_ecb_encrypt(stream_output[dir],
b,
stream_sched[dir], 1);
bcopy((void *)b, (void *)stream_feed[dir], sizeof(Block));
stream_index[dir] = 1; /* Next time will be 1 */
index = 0; /* But now use 0 */
}
/*
* On encryption, we store (feed ^ data) which is cypher
* On decryption we store (data) which is cypher
*/
if (dir == DIR_DECRYPT)
return(stream_output[dir][index] =
(stream_feed[dir][index] ^ data));
else
return((stream_output[dir][index] = data) ^
stream_feed[dir][index]);
}
#endif