559 lines
14 KiB
C
559 lines
14 KiB
C
/*-
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* Copyright (c) 1991 The Regents of the University of California.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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/*static char sccsid[] = "from: @(#)krb_des.c 5.1 (Berkeley) 2/28/91";*/
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static char rcsid[] = "$Id: krb_des.c,v 1.2 1993/08/01 18:32:31 mycroft Exp $";
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#endif /* not lint */
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/*
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* Copyright (C) 1990 by the Massachusetts Institute of Technology
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*
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* Export of this software from the United States of America is assumed
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* to require a specific license from the United States Government.
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* It is the responsibility of any person or organization contemplating
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* export to obtain such a license before exporting.
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*
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* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
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* distribute this software and its documentation for any purpose and
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* without fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright notice and
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* this permission notice appear in supporting documentation, and that
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* the name of M.I.T. not be used in advertising or publicity pertaining
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* to distribution of the software without specific, written prior
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* permission. M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is" without express
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* or implied warranty.
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*/
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#if defined(AUTHENTICATE) && defined(ENCRYPT) && defined(KRBDES_ENCRYPT)
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#include <arpa/telnet.h>
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#include <stdio.h>
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#ifdef __STDC__
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#include <stdlib.h>
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#endif
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#include "encrypt.h"
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#include "key-proto.h"
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#include "misc-proto.h"
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extern encrypt_debug_mode;
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static Block krbdes_key = { 0 };
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static Schedule krbdes_sched = { 0 };
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static Block input_feed = { 0 };
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static Block output_feed = { 0 };
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static Block temp_feed = { 0 };
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static unsigned char str_feed[64] = { IAC, SB, TELOPT_ENCRYPT,
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ENCRYPT_IS,
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ENCTYPE_KRBDES, };
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void
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krbdes_init(server)
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int server;
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{
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bzero((void *)krbdes_key, sizeof(Block));
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bzero((void *)krbdes_sched, sizeof(Schedule));
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bzero((void *)input_feed, sizeof(Block));
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bzero((void *)output_feed, sizeof(Block));
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}
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#define KRBDES_FEED_INIT 1
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#define KRBDES_FEED_VRFY 2
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#define KRBDES_FEED_FAIL 3
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#define KRBDES_FEED_OK 4
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#define KRBDES_FEED_VRFY_FAIL 5
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/*
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* Returns:
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* -1: some error. Negotiation is done, encryption not ready.
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* 0: Successful, initial negotiation all done.
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* 1: successful, negotiation not done yet.
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* 2: Not yet. Other things (like getting the key from
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* Kerberos) have to happen before we can continue.
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*/
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#define NOT_YET 2
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#define IN_PROGRESS 1
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#define SUCCESS 0
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#define FAILED -1
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int state[2] = { NOT_YET, NOT_YET };
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#define ENCRYPT_STATE 0
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#define DECRYPT_STATE 1
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/*
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* This is where we keep track of the fact that there has been a
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* call to krbdes_start(), but we haven't gotten a valid key from
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* kerberos, so that when (if) it does come in, we can continue with
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* the initial encryption startup.
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*/
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static int need_start;
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int
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krbdes_start(dir, server)
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int dir;
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int server;
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{
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Block b;
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int x;
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unsigned char *p;
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switch (dir) {
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case DIR_DECRYPT:
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/*
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* This is simply a request to have the other side
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* start output (our input). He will negotiate a
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* feed so we need not look for it.
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*/
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if (!VALIDKEY(krbdes_key))
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return(state[DECRYPT_STATE]);
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if (state[DECRYPT_STATE] == NOT_YET)
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state[DECRYPT_STATE] = IN_PROGRESS;
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return(state[DECRYPT_STATE]);
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case DIR_ENCRYPT:
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if (!VALIDKEY(krbdes_key)) {
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need_start = 1;
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return(state[ENCRYPT_STATE]);
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}
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if (state[ENCRYPT_STATE] == IN_PROGRESS)
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return(IN_PROGRESS);
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if (VALIDKEY(output_feed))
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return(SUCCESS);
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if (encrypt_debug_mode)
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printf("Creating new feed\r\n");
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/*
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* Create a random feed and send it over encrypted.
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* The other side will decrypt it, xor in 'KRBDES'
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* and then recrypt it and send it back.
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*/
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des_new_random_key(temp_feed);
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des_ecb_encrypt(temp_feed, b, krbdes_sched, 1);
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str_feed[3] = ENCRYPT_IS;
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p = str_feed + 5;
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*p++ = KRBDES_FEED_INIT;
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for (x = 0; x < sizeof(Block); ++x) {
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if ((*p++ = b[x]) == IAC)
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*p++ = IAC;
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}
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*p++ = IAC;
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*p++ = SE;
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printsub('>', &str_feed[2], p - &str_feed[2]);
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net_write(str_feed, p - str_feed);
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temp_feed[0] ^= 'K';
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temp_feed[1] ^= 'R';
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temp_feed[2] ^= 'B';
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temp_feed[3] ^= 'D';
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temp_feed[4] ^= 'E';
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temp_feed[5] ^= 'S';
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state[ENCRYPT_STATE] = IN_PROGRESS;
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return(IN_PROGRESS);
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default:
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return(FAILED);
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}
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}
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/*
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* Returns:
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* -1: some error. Negotiation is done, encryption not ready.
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* 0: Successful, initial negotiation all done.
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* 1: successful, negotiation not done yet.
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*/
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int
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krbdes_is(data, cnt)
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unsigned char *data;
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int cnt;
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{
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int x;
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unsigned char *p;
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unsigned char *why = 0;
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Block b;
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if (cnt-- < 1) {
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why = (unsigned char *)"Bad IS suboption";
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goto failure;
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}
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switch (*data++) {
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case KRBDES_FEED_INIT:
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if (cnt != sizeof(Block)) {
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if (encrypt_debug_mode)
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printf("Use Feed failed on size\r\n");
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why = (unsigned char *)"Bad block size";
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goto failure;
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}
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if (!VALIDKEY(krbdes_key)) {
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if (encrypt_debug_mode)
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printf("Use Feed failed on key\r\n");
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why = (unsigned char *)"Invalid key";
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goto failure;
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}
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if (encrypt_debug_mode)
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printf("Have a Use Feed\r\n");
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bcopy((void *)data, (void *)b, sizeof(Block));
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des_ecb_encrypt(b, input_feed, krbdes_sched, 0);
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input_feed[0] ^= 'K';
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input_feed[1] ^= 'R';
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input_feed[2] ^= 'B';
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input_feed[3] ^= 'D';
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input_feed[4] ^= 'E';
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input_feed[5] ^= 'S';
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des_ecb_encrypt(input_feed, b, krbdes_sched, 1);
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str_feed[3] = ENCRYPT_REPLY;
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p = str_feed + 5;
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*p++ = KRBDES_FEED_VRFY;
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for (x = 0; x < sizeof(Block); ++x) {
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if ((*p++ = b[x]) == IAC)
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*p++ = IAC;
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}
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*p++ = IAC;
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*p++ = SE;
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printsub('>', &str_feed[2], p - &str_feed[2]);
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net_write(str_feed, p - str_feed);
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if (encrypt_debug_mode)
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printf("Initializing Decrypt stream\r\n");
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key_stream_init(krbdes_key, input_feed, DIR_DECRYPT);
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state[DECRYPT_STATE] = IN_PROGRESS;
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return(IN_PROGRESS);
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case KRBDES_FEED_OK:
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state[DECRYPT_STATE] = SUCCESS;
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return(SUCCESS);
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case KRBDES_FEED_FAIL:
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state[DECRYPT_STATE] = FAILED;
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return(FAILED);
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default:
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if (encrypt_debug_mode) {
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printf("Unknown option type: %d\r\n", data[-1]);
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printd(data, cnt);
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printf("\r\n");
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}
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why = (unsigned char *)"Unknown sub-suboption";
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failure:
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/*
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* We failed. Send an empty KRBDES_FEED_VRFY option
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* to the other side so it will know that things
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* failed.
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*/
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str_feed[3] = ENCRYPT_REPLY;
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p = str_feed + 5;
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*p++ = KRBDES_FEED_VRFY_FAIL;
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if (why) {
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while (*why) {
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if ((*p++ = *why++) == IAC)
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*p++ = IAC;
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}
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}
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*p++ = IAC;
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*p++ = SE;
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printsub('>', &str_feed[2], p - &str_feed[2]);
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net_write(str_feed, p - str_feed);
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state[DECRYPT_STATE] = FAILED;
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return(FAILED);
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}
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}
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/*
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* Returns:
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* -1: some error. Negotiation is done, encryption not ready.
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* 0: Successful, initial negotiation all done.
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* 1: successful, negotiation not done yet.
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*/
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int
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krbdes_reply(data, cnt)
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unsigned char *data;
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int cnt;
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{
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int x;
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unsigned char *p;
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unsigned char *why = 0;
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Block b;
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if (cnt-- < 1) {
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why = (unsigned char *)"Bad REPLY suboption";
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goto failure;
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}
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switch (*data++) {
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case KRBDES_FEED_VRFY:
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if (cnt != sizeof(Block)) {
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if (encrypt_debug_mode)
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printf("Have Feed failed on size\r\n");
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why = (unsigned char *)"Bad block size";
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goto failure;
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}
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if (!VALIDKEY(krbdes_key)) {
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if (encrypt_debug_mode)
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printf("Have Feed failed on key\r\n");
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why = (unsigned char *)"Invalid key";
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goto failure;
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}
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if (encrypt_debug_mode)
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printf("Have a Test Feed\r\n");
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bcopy((void *)data, (void *)b, sizeof(Block));
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des_ecb_encrypt(b, output_feed, krbdes_sched, 0);
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if (!SAMEKEY(output_feed, temp_feed)) {
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if (encrypt_debug_mode)
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printf("Have Feed failed on challange\r\n");
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bzero((void *)output_feed, sizeof(Block));
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why = (unsigned char*)"Challange decrypt failed";
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goto failure;
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}
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if (encrypt_debug_mode)
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printf("Initializing Encrypt stream\r\n");
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key_stream_init(krbdes_key, output_feed, DIR_ENCRYPT);
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str_feed[3] = ENCRYPT_IS;
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p = str_feed + 5;
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*p++ = KRBDES_FEED_OK;
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*p++ = IAC;
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*p++ = SE;
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printsub('>', &str_feed[2], p - &str_feed[2]);
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net_write(str_feed, p - str_feed);
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state[ENCRYPT_STATE] = SUCCESS;
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return(SUCCESS);
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default:
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if (encrypt_debug_mode) {
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printf("Unknown option type: %d\r\n", data[-1]);
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printd(data, cnt);
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printf("\r\n");
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}
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why = (unsigned char *)"Unknown sub-suboption";
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failure:
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str_feed[3] = ENCRYPT_IS;
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p = str_feed + 5;
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*p++ = KRBDES_FEED_FAIL;
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if (why) {
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while (*why) {
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if ((*p++ = *why++) == IAC)
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*p++ = IAC;
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}
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}
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*p++ = IAC;
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*p++ = SE;
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printsub('>', &str_feed[2], p - &str_feed[2]);
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net_write(str_feed, p - str_feed);
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state[ENCRYPT_STATE] = FAILED;
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return(FAILED);
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}
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}
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void
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krbdes_encrypt(s, c)
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unsigned char *s;
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int c;
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{
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while (c-- > 0) {
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*s = key_stream(DIR_ENCRYPT, *s);
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++s;
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}
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}
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int
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krbdes_decrypt(c)
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int c;
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{
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return(key_stream(DIR_DECRYPT, c));
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#ifdef ndef
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if (c == -1) {
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++use;
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return(0);
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}
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if (use) {
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use = 0;
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} else {
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last = key_stream(DIR_DECRYPT, c);
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}
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return(last ^ c);
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#endif
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}
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void
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krbdes_session(key, server)
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Session_Key *key;
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int server;
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{
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static once = 1;
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if (!key || key->type != SK_DES) {
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if (encrypt_debug_mode)
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printf("Can't set krbdes's session key (%d != %d)\r\n",
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key ? key->type : -1, SK_DES);
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return;
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}
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bcopy((void *)key->data, (void *)krbdes_key, sizeof(Block));
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if (once) {
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des_set_random_generator_seed(krbdes_key);
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once = 0;
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}
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des_key_sched(krbdes_key, krbdes_sched);
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/*
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* Now look to see if krbdes_start() was was waiting for
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* the key to show up. If so, go ahead an call it now
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* that we have the key.
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*/
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if (need_start) {
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krbdes_start(DIR_ENCRYPT, server);
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need_start = 0;
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}
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}
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void
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krbdes_printsub(data, cnt, buf, buflen)
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unsigned char *data, *buf;
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int cnt, buflen;
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{
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char lbuf[32];
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register int i;
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char *cp;
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buf[buflen-1] = '\0'; /* make sure it's NULL terminated */
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buflen -= 1;
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switch(data[2]) {
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case KRBDES_FEED_OK:
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cp = "FEED_OK";
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goto common1;
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case KRBDES_FEED_FAIL:
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cp = "FEED_FAIL";
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common1:
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for (; (buflen > 0) && (*buf = *cp++); buf++)
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buflen--;
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if (cnt > 3) {
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if (buflen <= 0)
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break;
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*buf++ = ' ';
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if (--buflen <= 0)
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break;
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*buf++ = '"';
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for (i = 3; i < cnt && buflen > 0; i++, buflen--)
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*buf++ = data[i];
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if (buflen <= 0)
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break;
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*buf++ = '"';
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--buflen;
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}
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if (buflen <= 0)
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break;
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*buf++ = '\0';
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break;
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case KRBDES_FEED_INIT:
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cp = "FEED_INIT ";
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goto common2;
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case KRBDES_FEED_VRFY:
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cp = "FEED_VRFY ";
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goto common2;
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default:
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sprintf(lbuf, " %d (unknown)", data[2]);
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cp = lbuf;
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common2:
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for (; (buflen > 0) && (*buf = *cp++); buf++)
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buflen--;
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for (i = 3; i < cnt; i++) {
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sprintf(lbuf, " %d", data[i]);
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for (cp = lbuf; (buflen > 0) && (*buf = *cp++); buf++)
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buflen--;
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}
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break;
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}
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}
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static Block stream_output[2];
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static Block stream_feed[2];
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static Schedule stream_sched[2];
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static int stream_index[2];
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void
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key_stream_init(key, seed, dir)
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Block key;
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Block seed;
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int dir;
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{
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des_key_sched(key, stream_sched[--dir]);
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bcopy((void *)seed, (void *)stream_output[dir], sizeof(Block));
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stream_index[dir] = sizeof(Block);
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}
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unsigned char
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key_stream(dir, data)
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int dir;
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int data; /* data de/encrypting */
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{
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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
|