text: /*-
   * 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. 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: src/crypto/telnet/libtelnet/enc_des.c,v 1.3.2.2 2003/02/14 22:38:13 nectar Exp $
   * $DragonFly: src/crypto/telnet/libtelnet/enc_des.c,v 1.2 2003/06/17 04:24:37 dillon Exp $
   *
   * @(#)enc_des.c	8.3 (Berkeley) 5/30/95
   * $FreeBSD: src/crypto/telnet/libtelnet/enc_des.c,v 1.3.2.2 2003/02/14 22:38:13 nectar Exp $
   */
  
  #ifdef	ENCRYPTION
  # ifdef	AUTHENTICATION
  #include <arpa/telnet.h>
  #include <openssl/des.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "encrypt.h"
  #include "key-proto.h"
  #include "misc-proto.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 fb {
  	Block krbdes_key;
  	Schedule krbdes_sched;
  	Block temp_feed;
  	unsigned char fb_feed[64];
  	int need_start;
  	int state[2];
  	int keyid[2];
  	struct stinfo {
  		Block		str_output;
  		Block		str_feed;
  		Block		str_iv;
  		Block		str_ikey;
  		Schedule	str_sched;
  		int		str_index;
  		int		str_flagshift;
  	} streams[2];
  };
  
  static struct fb fb[2];
  
  struct keyidlist {
  	const 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(Block, 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(Block, struct stinfo *);
  int fb64_keyid(int, unsigned char *, int *, struct fb *);
  
  void
  cfb64_init(int server __unused)
  {
  	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 __unused)
  {
  	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((void *)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 __unused)
  {
  	size_t 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.
  		 */
  		DES_random_key((Block *)fbp->temp_feed);
  		DES_ecb_encrypt((Block *)fbp->temp_feed, (Block *)fbp->temp_feed,
  				&fbp->krbdes_sched, 1);
  		p = fbp->fb_feed + 3;
  		*p++ = ENCRYPT_IS;
  		p++;
  		*p++ = FB64_IV;
  		for (x = 0; x < sizeof(Block); ++x) {
  			if ((*p++ = fbp->temp_feed[x]) == IAC)
  				*p++ = IAC;
  		}
  		*p++ = IAC;
  		*p++ = SE;
  		printsub('>', &fbp->fb_feed[2], p - &fbp->fb_feed[2]);
  		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(Block)) {
  			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((void *)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]);
  		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]);
  		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, "\0", 1, 1);
  		break;
  
  	case FB64_IV_BAD:
  		memset(fbp->temp_feed, 0, sizeof(Block));
  		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;
  	}
  	memmove((void *)fbp->krbdes_key, (void *)key->data, sizeof(Block));
  
  	fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_ENCRYPT-1]);
  	fb64_stream_key(fbp->krbdes_key, &fbp->streams[DIR_DECRYPT-1]);
  
  	DES_key_sched((Block *)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, const 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:
  		sprintf(lbuf, "%s_IV", type);
  		cp = lbuf;
  		goto common;
  
  	case FB64_IV_OK:
  		sprintf(lbuf, "%s_IV_OK", type);
  		cp = lbuf;
  		goto common;
  
  	case FB64_IV_BAD:
  		sprintf(lbuf, "%s_IV_BAD", type);
  		cp = lbuf;
  		goto common;
  
  	default:
  		sprintf(lbuf, " %d (unknown)", data[2]);
  		cp = lbuf;
  	common:
  		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;
  	}
  }
  
  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(Block seed, struct stinfo *stp)
  {
  
  	memmove((void *)stp->str_iv, (void *)seed, sizeof(Block));
  	memmove((void *)stp->str_output, (void *)seed, sizeof(Block));
  
  	DES_key_sched((Block *)stp->str_ikey, &stp->str_sched);
  
  	stp->str_index = sizeof(Block);
  }
  
  void
  fb64_stream_key(Block key, struct stinfo *stp)
  {
  	memmove((void *)stp->str_ikey, (void *)key, sizeof(Block));
  	DES_key_sched((Block *)key, &stp->str_sched);
  
  	memmove((void *)stp->str_output, (void *)stp->str_iv, sizeof(Block));
  
  	stp->str_index = sizeof(Block);
  }
  
  /*
   * 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 idx;
  
  	idx = stp->str_index;
  	while (c-- > 0) {
  		if (idx == sizeof(Block)) {
  			Block b;
  			DES_ecb_encrypt((Block *)stp->str_output, (Block *)b, &stp->str_sched, 1);
  			memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
  			idx = 0;
  		}
  
  		/* On encryption, we store (feed ^ data) which is cypher */
  		*s = stp->str_output[idx] = (stp->str_feed[idx] ^ *s);
  		s++;
  		idx++;
  	}
  	stp->str_index = idx;
  }
  
  int
  cfb64_decrypt(int data)
  {
  	struct stinfo *stp = &fb[CFB].streams[DIR_DECRYPT-1];
  	int idx;
  
  	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);
  	}
  
  	idx = stp->str_index++;
  	if (idx == sizeof(Block)) {
  		Block b;
  		DES_ecb_encrypt((Block *)stp->str_output, (Block *)b, &stp->str_sched, 1);
  		memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
  		stp->str_index = 1;	/* Next time will be 1 */
  		idx = 0;		/* But now use 0 */
  	}
  
  	/* On decryption we store (data) which is cypher. */
  	stp->str_output[idx] = data;
  	return(data ^ stp->str_feed[idx]);
  }
  
  /*
   * 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 idx;
  
  	idx = stp->str_index;
  	while (c-- > 0) {
  		if (idx == sizeof(Block)) {
  			Block b;
  			DES_ecb_encrypt((Block *)stp->str_feed, (Block *)b, &stp->str_sched, 1);
  			memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
  			idx = 0;
  		}
  		*s++ ^= stp->str_feed[idx];
  		idx++;
  	}
  	stp->str_index = idx;
  }
  
  int
  ofb64_decrypt(int data)
  {
  	struct stinfo *stp = &fb[OFB].streams[DIR_DECRYPT-1];
  	int idx;
  
  	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);
  	}
  
  	idx = stp->str_index++;
  	if (idx == sizeof(Block)) {
  		Block b;
  		DES_ecb_encrypt((Block *)stp->str_feed, (Block *)b, &stp->str_sched, 1);
  		memmove((void *)stp->str_feed, (void *)b, sizeof(Block));
  		stp->str_index = 1;	/* Next time will be 1 */
  		idx = 0;		/* But now use 0 */
  	}
  
  	return(data ^ stp->str_feed[idx]);
  }
  # endif	/* AUTHENTICATION */
  #endif	/* ENCRYPTION */
  