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|
/*-
* Copyright (c) 1991, 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.
*/
/* $FreeBSD$ */
#include <config.h>
RCSID("$Id: enc_des.c,v 1.16 1998/07/09 23:16:23 assar Exp $");
#if defined(AUTHENTICATION) && defined(ENCRYPTION) && defined(DES_ENCRYPTION)
#include <arpa/telnet.h>
#include <stdio.h>
#ifdef __STDC__
#include <stdlib.h>
#include <string.h>
#endif
#include <roken.h>
#ifdef SOCKS
#include <socks.h>
#endif
#include "encrypt.h"
#include "misc-proto.h"
#include <openssl/des.h>
extern int encrypt_debug_mode;
#define CFB 0
#define OFB 1
#define NO_SEND_IV 1
#define NO_RECV_IV 2
#define NO_KEYID 4
#define IN_PROGRESS (NO_SEND_IV|NO_RECV_IV|NO_KEYID)
#define SUCCESS 0
#define FAILED -1
struct stinfo {
des_cblock str_output;
des_cblock str_feed;
des_cblock str_iv;
des_cblock str_ikey;
des_key_schedule str_sched;
int str_index;
int str_flagshift;
};
struct fb {
des_cblock krbdes_key;
des_key_schedule krbdes_sched;
des_cblock temp_feed;
unsigned char fb_feed[64];
int need_start;
int state[2];
int keyid[2];
int once;
struct stinfo streams[2];
};
static struct fb fb[2];
struct keyidlist {
char *keyid;
int keyidlen;
char *key;
int keylen;
int flags;
} keyidlist [] = {
{ "\0", 1, 0, 0, 0 }, /* default key of zero */
{ 0, 0, 0, 0, 0 }
};
#define KEYFLAG_MASK 03
#define KEYFLAG_NOINIT 00
#define KEYFLAG_INIT 01
#define KEYFLAG_OK 02
#define KEYFLAG_BAD 03
#define KEYFLAG_SHIFT 2
#define SHIFT_VAL(a,b) (KEYFLAG_SHIFT*((a)+((b)*2)))
#define FB64_IV 1
#define FB64_IV_OK 2
#define FB64_IV_BAD 3
void fb64_stream_iv (des_cblock, struct stinfo *);
void fb64_init (struct fb *);
static int fb64_start (struct fb *, int, int);
int fb64_is (unsigned char *, int, struct fb *);
int fb64_reply (unsigned char *, int, struct fb *);
static void fb64_session (Session_Key *, int, struct fb *);
void fb64_stream_key (des_cblock, struct stinfo *);
int fb64_keyid (int, unsigned char *, int *, struct fb *);
void cfb64_init(int server)
{
fb64_init(&fb[CFB]);
fb[CFB].fb_feed[4] = ENCTYPE_DES_CFB64;
fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, CFB);
fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, CFB);
}
void ofb64_init(int server)
{
fb64_init(&fb[OFB]);
fb[OFB].fb_feed[4] = ENCTYPE_DES_OFB64;
fb[CFB].streams[0].str_flagshift = SHIFT_VAL(0, OFB);
fb[CFB].streams[1].str_flagshift = SHIFT_VAL(1, OFB);
}
void fb64_init(struct fb *fbp)
{
memset(fbp,0, sizeof(*fbp));
fbp->state[0] = fbp->state[1] = FAILED;
fbp->fb_feed[0] = IAC;
fbp->fb_feed[1] = SB;
fbp->fb_feed[2] = TELOPT_ENCRYPT;
fbp->fb_feed[3] = ENCRYPT_IS;
}
/*
* 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.
*/
int cfb64_start(int dir, int server)
{
return(fb64_start(&fb[CFB], dir, server));
}
int ofb64_start(int dir, int server)
{
return(fb64_start(&fb[OFB], dir, server));
}
static int fb64_start(struct fb *fbp, int dir, int server)
{
int x;
unsigned char *p;
int state;
switch (dir) {
case DIR_DECRYPT:
/*
* This is simply a request to have the other side
* start output (our input). He will negotiate an
* IV so we need not look for it.
*/
state = fbp->state[dir-1];
if (state == FAILED)
state = IN_PROGRESS;
break;
case DIR_ENCRYPT:
state = fbp->state[dir-1];
if (state == FAILED)
state = IN_PROGRESS;
else if ((state & NO_SEND_IV) == 0) {
break;
}
if (!VALIDKEY(fbp->krbdes_key)) {
fbp->need_start = 1;
break;
}
state &= ~NO_SEND_IV;
state |= NO_RECV_IV;
if (encrypt_debug_mode)
printf("Creating new feed\r\n");
/*
* Create a random feed and send it over.
*/
#ifndef OLD_DES_RANDOM_KEY
des_new_random_key(&fbp->temp_feed);
#else
/*
* From des_cryp.man "If the des_check_key flag is non-zero,
* des_set_key will check that the key passed is
* of odd parity and is not a week or semi-weak key."
*/
do {
des_random_key(fbp->temp_feed);
des_set_odd_parity(fbp->temp_feed);
} while (des_is_weak_key(fbp->temp_feed));
#endif
des_ecb_encrypt(&fbp->temp_feed,
&fbp->temp_feed,
fbp->krbdes_sched, 1);
p = fbp->fb_feed + 3;
*p++ = ENCRYPT_IS;
p++;
*p++ = FB64_IV;
for (x = 0; x < sizeof(des_cblock); ++x) {
if ((*p++ = fbp->temp_feed[x]) == IAC)
*p++ = IAC;
}
*p++ = IAC;
*p++ = SE;
printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
telnet_net_write(fbp->fb_feed, p - fbp->fb_feed);
break;
default:
return(FAILED);
}
return(fbp->state[dir-1] = state);
}
/*
* Returns:
* -1: some error. Negotiation is done, encryption not ready.
* 0: Successful, initial negotiation all done.
* 1: successful, negotiation not done yet.
*/
int cfb64_is(unsigned char *data, int cnt)
{
return(fb64_is(data, cnt, &fb[CFB]));
}
int ofb64_is(unsigned char *data, int cnt)
{
return(fb64_is(data, cnt, &fb[OFB]));
}
int fb64_is(unsigned char *data, int cnt, struct fb *fbp)
{
unsigned char *p;
int state = fbp->state[DIR_DECRYPT-1];
if (cnt-- < 1)
goto failure;
switch (*data++) {
case FB64_IV:
if (cnt != sizeof(des_cblock)) {
if (encrypt_debug_mode)
printf("CFB64: initial vector failed on size\r\n");
state = FAILED;
goto failure;
}
if (encrypt_debug_mode)
printf("CFB64: initial vector received\r\n");
if (encrypt_debug_mode)
printf("Initializing Decrypt stream\r\n");
fb64_stream_iv(data, &fbp->streams[DIR_DECRYPT-1]);
p = fbp->fb_feed + 3;
*p++ = ENCRYPT_REPLY;
p++;
*p++ = FB64_IV_OK;
*p++ = IAC;
*p++ = SE;
printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
telnet_net_write(fbp->fb_feed, p - fbp->fb_feed);
state = fbp->state[DIR_DECRYPT-1] = IN_PROGRESS;
break;
default:
if (encrypt_debug_mode) {
printf("Unknown option type: %d\r\n", *(data-1));
printd(data, cnt);
printf("\r\n");
}
/* FALL THROUGH */
failure:
/*
* We failed. Send an FB64_IV_BAD option
* to the other side so it will know that
* things failed.
*/
p = fbp->fb_feed + 3;
*p++ = ENCRYPT_REPLY;
p++;
*p++ = FB64_IV_BAD;
*p++ = IAC;
*p++ = SE;
printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
telnet_net_write(fbp->fb_feed, p - fbp->fb_feed);
break;
}
return(fbp->state[DIR_DECRYPT-1] = state);
}
/*
* Returns:
* -1: some error. Negotiation is done, encryption not ready.
* 0: Successful, initial negotiation all done.
* 1: successful, negotiation not done yet.
*/
int cfb64_reply(unsigned char *data, int cnt)
{
return(fb64_reply(data, cnt, &fb[CFB]));
}
int ofb64_reply(unsigned char *data, int cnt)
{
return(fb64_reply(data, cnt, &fb[OFB]));
}
int fb64_reply(unsigned char *data, int cnt, struct fb *fbp)
{
int state = fbp->state[DIR_ENCRYPT-1];
if (cnt-- < 1)
goto failure;
switch (*data++) {
case FB64_IV_OK:
fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]);
if (state == FAILED)
state = IN_PROGRESS;
state &= ~NO_RECV_IV;
encrypt_send_keyid(DIR_ENCRYPT, (unsigned char *)"\0", 1, 1);
break;
case FB64_IV_BAD:
memset(fbp->temp_feed, 0, sizeof(des_cblock));
fb64_stream_iv(fbp->temp_feed, &fbp->streams[DIR_ENCRYPT-1]);
state = FAILED;
break;
default:
if (encrypt_debug_mode) {
printf("Unknown option type: %d\r\n", data[-1]);
printd(data, cnt);
printf("\r\n");
}
/* FALL THROUGH */
failure:
state = FAILED;
break;
}
return(fbp->state[DIR_ENCRYPT-1] = state);
}
void cfb64_session(Session_Key *key, int server)
{
fb64_session(key, server, &fb[CFB]);
}
void ofb64_session(Session_Key *key, int server)
{
fb64_session(key, server, &fb[OFB]);
}
static void fb64_session(Session_Key *key, int server, struct fb *fbp)
{
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;
}
memcpy(fbp->krbdes_key, key->data, sizeof(des_cblock));
fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]);
fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]);
if (fbp->once == 0) {
#ifndef OLD_DES_RANDOM_KEY
des_init_random_number_generator(&fbp->krbdes_key);
#endif
fbp->once = 1;
}
des_key_sched(&fbp->krbdes_key, fbp->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 (fbp->need_start) {
fbp->need_start = 0;
fb64_start(fbp, DIR_ENCRYPT, server);
}
}
/*
* We only accept a keyid of 0. If we get a keyid of
* 0, then mark the state as SUCCESS.
*/
int cfb64_keyid(int dir, unsigned char *kp, int *lenp)
{
return(fb64_keyid(dir, kp, lenp, &fb[CFB]));
}
int ofb64_keyid(int dir, unsigned char *kp, int *lenp)
{
return(fb64_keyid(dir, kp, lenp, &fb[OFB]));
}
int fb64_keyid(int dir, unsigned char *kp, int *lenp, struct fb *fbp)
{
int state = fbp->state[dir-1];
if (*lenp != 1 || (*kp != '\0')) {
*lenp = 0;
return(state);
}
if (state == FAILED)
state = IN_PROGRESS;
state &= ~NO_KEYID;
return(fbp->state[dir-1] = state);
}
void fb64_printsub(unsigned char *data, int cnt,
unsigned char *buf, int buflen, char *type)
{
char lbuf[32];
int i;
char *cp;
buf[buflen-1] = '\0'; /* make sure it's NULL terminated */
buflen -= 1;
switch(data[2]) {
case FB64_IV:
snprintf(lbuf, sizeof(lbuf), "%s_IV", type);
cp = lbuf;
goto common;
case FB64_IV_OK:
snprintf(lbuf, sizeof(lbuf), "%s_IV_OK", type);
cp = lbuf;
goto common;
case FB64_IV_BAD:
snprintf(lbuf, sizeof(lbuf), "%s_IV_BAD", type);
cp = lbuf;
goto common;
default:
snprintf(lbuf, sizeof(lbuf), " %d (unknown)", data[2]);
cp = lbuf;
common:
for (; (buflen > 0) && (*buf = *cp++); buf++)
buflen--;
for (i = 3; i < cnt; i++) {
snprintf(lbuf, sizeof(lbuf), " %d", data[i]);
for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++)
buflen--;
}
break;
}
}
void cfb64_printsub(unsigned char *data, int cnt,
unsigned char *buf, int buflen)
{
fb64_printsub(data, cnt, buf, buflen, "CFB64");
}
void ofb64_printsub(unsigned char *data, int cnt,
unsigned char *buf, int buflen)
{
fb64_printsub(data, cnt, buf, buflen, "OFB64");
}
void fb64_stream_iv(des_cblock seed, struct stinfo *stp)
{
memcpy(stp->str_iv, seed,sizeof(des_cblock));
memcpy(stp->str_output, seed, sizeof(des_cblock));
des_key_sched(&stp->str_ikey, stp->str_sched);
stp->str_index = sizeof(des_cblock);
}
void fb64_stream_key(des_cblock key, struct stinfo *stp)
{
memcpy(stp->str_ikey, key, sizeof(des_cblock));
des_key_sched((des_cblock*)key, stp->str_sched);
memcpy(stp->str_output, stp->str_iv, sizeof(des_cblock));
stp->str_index = sizeof(des_cblock);
}
/*
* DES 64 bit Cipher Feedback
*
* key --->+-----+
* +->| DES |--+
* | +-----+ |
* | v
* INPUT --(--------->(+)+---> DATA
* | |
* +-------------+
*
*
* Given:
* iV: Initial vector, 64 bits (8 bytes) long.
* Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt).
* On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output.
*
* V0 = DES(iV, key)
* On = Dn ^ Vn
* V(n+1) = DES(On, key)
*/
void cfb64_encrypt(unsigned char *s, int c)
{
struct stinfo *stp = &fb[CFB].streams[DIR_ENCRYPT-1];
int index;
index = stp->str_index;
while (c-- > 0) {
if (index == sizeof(des_cblock)) {
des_cblock b;
des_ecb_encrypt(&stp->str_output, &b,stp->str_sched, 1);
memcpy(stp->str_feed, b, sizeof(des_cblock));
index = 0;
}
/* On encryption, we store (feed ^ data) which is cypher */
*s = stp->str_output[index] = (stp->str_feed[index] ^ *s);
s++;
index++;
}
stp->str_index = index;
}
int cfb64_decrypt(int data)
{
struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1];
int index;
if (data == -1) {
/*
* Back up one byte. It is assumed that we will
* never back up more than one byte. If we do, this
* may or may not work.
*/
if (stp->str_index)
--stp->str_index;
return(0);
}
index = stp->str_index++;
if (index == sizeof(des_cblock)) {
des_cblock b;
des_ecb_encrypt(&stp->str_output,&b, stp->str_sched, 1);
memcpy(stp->str_feed, b, sizeof(des_cblock));
stp->str_index = 1; /* Next time will be 1 */
index = 0; /* But now use 0 */
}
/* On decryption we store (data) which is cypher. */
stp->str_output[index] = data;
return(data ^ stp->str_feed[index]);
}
/*
* DES 64 bit Output Feedback
*
* key --->+-----+
* +->| DES |--+
* | +-----+ |
* +-----------+
* v
* INPUT -------->(+) ----> DATA
*
* Given:
* iV: Initial vector, 64 bits (8 bytes) long.
* Dn: the nth chunk of 64 bits (8 bytes) of data to encrypt (decrypt).
* On: the nth chunk of 64 bits (8 bytes) of encrypted (decrypted) output.
*
* V0 = DES(iV, key)
* V(n+1) = DES(Vn, key)
* On = Dn ^ Vn
*/
void ofb64_encrypt(unsigned char *s, int c)
{
struct stinfo *stp = &fb[OFB].streams[DIR_ENCRYPT-1];
int index;
index = stp->str_index;
while (c-- > 0) {
if (index == sizeof(des_cblock)) {
des_cblock b;
des_ecb_encrypt(&stp->str_feed,&b, stp->str_sched, 1);
memcpy(stp->str_feed, b, sizeof(des_cblock));
index = 0;
}
*s++ ^= stp->str_feed[index];
index++;
}
stp->str_index = index;
}
int ofb64_decrypt(int data)
{
struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1];
int index;
if (data == -1) {
/*
* Back up one byte. It is assumed that we will
* never back up more than one byte. If we do, this
* may or may not work.
*/
if (stp->str_index)
--stp->str_index;
return(0);
}
index = stp->str_index++;
if (index == sizeof(des_cblock)) {
des_cblock b;
des_ecb_encrypt(&stp->str_feed,&b,stp->str_sched, 1);
memcpy(stp->str_feed, b, sizeof(des_cblock));
stp->str_index = 1; /* Next time will be 1 */
index = 0; /* But now use 0 */
}
return(data ^ stp->str_feed[index]);
}
#endif
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