encrypt.c

inetutils的源代码

/*-
 * 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.
 * 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[] = "@(#)encrypt.c	8.2 (Berkeley) 5/30/95";
#endif /* not lint */

/*
 * Copyright (C) 1990, 2000 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.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#ifdef	ENCRYPTION

#define	ENCRYPT_NAMES
#include <arpa/telnet.h>

#include "encrypt.h"
#include "misc.h"

#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef	NO_STRING_H
#include <strings.h>
#else
#include <string.h>
#endif

/*
 * These functions pointers point to the current routines
 * for encrypting and decrypting data.
 */
void	(*encrypt_output) P((unsigned char *, int));
int	(*decrypt_input) P((int));

int encrypt_debug_mode = 0;
static int decrypt_mode = 0;
static int encrypt_mode = 0;
static int encrypt_verbose = 0;
static int autoencrypt = 0;
static int autodecrypt = 0;
static int havesessionkey = 0;
static int Server = 0;
static char *Name = "Noname";

#define	typemask(x)	((x) > 0 ? 1 << ((x)-1) : 0)

static long i_support_encrypt = typemask(ENCTYPE_DES_CFB64)
				| typemask(ENCTYPE_DES_OFB64);
static long i_support_decrypt = typemask(ENCTYPE_DES_CFB64)
				| typemask(ENCTYPE_DES_OFB64);
static long i_wont_support_encrypt = 0;
static long i_wont_support_decrypt = 0;
#define	I_SUPPORT_ENCRYPT	(i_support_encrypt & ~i_wont_support_encrypt)
#define	I_SUPPORT_DECRYPT	(i_support_decrypt & ~i_wont_support_decrypt)

static long remote_supports_encrypt = 0;
static long remote_supports_decrypt = 0;

static Encryptions encryptions[] = {
#ifdef	DES_ENCRYPTION
    { "DES_CFB64",	ENCTYPE_DES_CFB64,
			cfb64_encrypt,
			cfb64_decrypt,
			cfb64_init,
			cfb64_start,
			cfb64_is,
			cfb64_reply,
			cfb64_session,
			cfb64_keyid,
			cfb64_printsub },
    { "DES_OFB64",	ENCTYPE_DES_OFB64,
			ofb64_encrypt,
			ofb64_decrypt,
			ofb64_init,
			ofb64_start,
			ofb64_is,
			ofb64_reply,
			ofb64_session,
			ofb64_keyid,
			ofb64_printsub },
#endif	/* DES_ENCRYPTION */
    { 0, },
};

static unsigned char str_send[64] = { IAC, SB, TELOPT_ENCRYPT,
					 ENCRYPT_SUPPORT };
static unsigned char str_suplen = 0;
static unsigned char str_start[72] = { IAC, SB, TELOPT_ENCRYPT };
static unsigned char str_end[] = { IAC, SB, TELOPT_ENCRYPT, 0, IAC, SE };

	Encryptions *
findencryption(type)
	int type;
{
	Encryptions *ep = encryptions;

	if (!(I_SUPPORT_ENCRYPT & remote_supports_decrypt & typemask(type)))
		return(0);
	while (ep->type && ep->type != type)
		++ep;
	return(ep->type ? ep : 0);
}

	Encryptions *
finddecryption(type)
	int type;
{
	Encryptions *ep = encryptions;

	if (!(I_SUPPORT_DECRYPT & remote_supports_encrypt & typemask(type)))
		return(0);
	while (ep->type && ep->type != type)
		++ep;
	return(ep->type ? ep : 0);
}

#define	MAXKEYLEN 64

static struct key_info {
	unsigned char keyid[MAXKEYLEN];
	int keylen;
	int dir;
	int *modep;
	Encryptions *(*getcrypt)();
} ki[2] = {
	{ { 0 }, 0, DIR_ENCRYPT, &encrypt_mode, findencryption },
	{ { 0 }, 0, DIR_DECRYPT, &decrypt_mode, finddecryption },
};

	void
encrypt_init(name, server)
	char *name;
	int server;
{
	Encryptions *ep = encryptions;

	Name = name;
	Server = server;
	i_support_encrypt = i_support_decrypt = 0;
	remote_supports_encrypt = remote_supports_decrypt = 0;
	encrypt_mode = 0;
	decrypt_mode = 0;
	encrypt_output = 0;
	decrypt_input = 0;
#ifdef notdef
	encrypt_verbose = !server;
#endif

	str_suplen = 4;

	while (ep->type) {
		if (encrypt_debug_mode)
			printf(">>>%s: I will support %s\r\n",
				Name, ENCTYPE_NAME(ep->type));
		i_support_encrypt |= typemask(ep->type);
		i_support_decrypt |= typemask(ep->type);
		if ((i_wont_support_decrypt & typemask(ep->type)) == 0)
			if ((str_send[str_suplen++] = ep->type) == IAC)
				str_send[str_suplen++] = IAC;
		if (ep->init)
			(*ep->init)(Server);
		++ep;
	}
	str_send[str_suplen++] = IAC;
	str_send[str_suplen++] = SE;
}

	void
encrypt_list_types()
{
	Encryptions *ep = encryptions;

	printf("Valid encryption types:\n");
	while (ep->type) {
		printf("\t%s (%d)\r\n", ENCTYPE_NAME(ep->type), ep->type);
		++ep;
	}
}

	int
EncryptEnable(type, mode)
	char *type, *mode;
{
	if (isprefix(type, "help") || isprefix(type, "?")) {
		printf("Usage: encrypt enable <type> [input|output]\n");
		encrypt_list_types();
		return(0);
	}
	if (EncryptType(type, mode))
		return(EncryptStart(mode));
	return(0);
}

	int
EncryptDisable(type, mode)
	char *type, *mode;
{
	register Encryptions *ep;
	int ret = 0;

	if (isprefix(type, "help") || isprefix(type, "?")) {
		printf("Usage: encrypt disable <type> [input|output]\n");
		encrypt_list_types();
	} else if ((ep = (Encryptions *)genget(type, encryptions,
						sizeof(Encryptions))) == 0) {
		printf("%s: invalid encryption type\n", type);
	} else if (Ambiguous(ep)) {
		printf("Ambiguous type '%s'\n", type);
	} else {
		if ((mode == 0) || (isprefix(mode, "input") ? 1 : 0)) {
			if (decrypt_mode == ep->type)
				EncryptStopInput();
			i_wont_support_decrypt |= typemask(ep->type);
			ret = 1;
		}
		if ((mode == 0) || (isprefix(mode, "output"))) {
			if (encrypt_mode == ep->type)
				EncryptStopOutput();
			i_wont_support_encrypt |= typemask(ep->type);
			ret = 1;
		}
		if (ret == 0)
			printf("%s: invalid encryption mode\n", mode);
	}
	return(ret);
}

	int
EncryptType(type, mode)
	char *type;
	char *mode;
{
	register Encryptions *ep;
	int ret = 0;

	if (isprefix(type, "help") || isprefix(type, "?")) {
		printf("Usage: encrypt type <type> [input|output]\n");
		encrypt_list_types();
	} else if ((ep = (Encryptions *)genget(type, encryptions,
						sizeof(Encryptions))) == 0) {
		printf("%s: invalid encryption type\n", type);
	} else if (Ambiguous(ep)) {
		printf("Ambiguous type '%s'\n", type);
	} else {
		if ((mode == 0) || isprefix(mode, "input")) {
			decrypt_mode = ep->type;
			i_wont_support_decrypt &= ~typemask(ep->type);
			ret = 1;
		}
		if ((mode == 0) || isprefix(mode, "output")) {
			encrypt_mode = ep->type;
			i_wont_support_encrypt &= ~typemask(ep->type);
			ret = 1;
		}
		if (ret == 0)
			printf("%s: invalid encryption mode\n", mode);
	}
	return(ret);
}

	int
EncryptStart(mode)
	char *mode;
{
	register int ret = 0;
	if (mode) {
		if (isprefix(mode, "input"))
			return(EncryptStartInput());
		if (isprefix(mode, "output"))
			return(EncryptStartOutput());
		if (isprefix(mode, "help") || isprefix(mode, "?")) {
			printf("Usage: encrypt start [input|output]\n");
			return(0);
		}
		printf("%s: invalid encryption mode 'encrypt start ?' for help\n", mode);
		return(0);
	}
	ret += EncryptStartInput();
	ret += EncryptStartOutput();
	return(ret);
}

	int
EncryptStartInput()
{
	if (decrypt_mode) {
		encrypt_send_request_start();
		return(1);
	}
	printf("No previous decryption mode, decryption not enabled\r\n");
	return(0);
}

	int
EncryptStartOutput()
{
	if (encrypt_mode) {
		encrypt_start_output(encrypt_mode);
		return(1);
	}
	printf("No previous encryption mode, encryption not enabled\r\n");
	return(0);
}

	int
EncryptStop(mode)
	char *mode;
{
	int ret = 0;
	if (mode) {
		if (isprefix(mode, "input"))
			return(EncryptStopInput());
		if (isprefix(mode, "output"))
			return(EncryptStopOutput());
		if (isprefix(mode, "help") || isprefix(mode, "?")) {
			printf("Usage: encrypt stop [input|output]\n");
			return(0);
		}
		printf("%s: invalid encryption mode 'encrypt stop ?' for help\n", mode);
		return(0);
	}
	ret += EncryptStopInput();
	ret += EncryptStopOutput();
	return(ret);
}

	int
EncryptStopInput()
{
	encrypt_send_request_end();
	return(1);
}

	int
EncryptStopOutput()
{
	encrypt_send_end();
	return(1);
}

	void
encrypt_display()
{
	if (encrypt_output)
		printf("Currently encrypting output with %s\r\n",
			ENCTYPE_NAME(encrypt_mode));
	if (decrypt_input)
		printf("Currently decrypting input with %s\r\n",
			ENCTYPE_NAME(decrypt_mode));
}

	int
EncryptStatus()
{
	if (encrypt_output)
		printf("Currently encrypting output with %s\r\n",
			ENCTYPE_NAME(encrypt_mode));
	else if (encrypt_mode) {
		printf("Currently output is clear text.\r\n");
		printf("Last encryption mode was %s\r\n",
			ENCTYPE_NAME(encrypt_mode));
	}
	if (decrypt_input) {
		printf("Currently decrypting input with %s\r\n",
			ENCTYPE_NAME(decrypt_mode));
	} else if (decrypt_mode) {
		printf("Currently input is clear text.\r\n");
		printf("Last decryption mode was %s\r\n",
			ENCTYPE_NAME(decrypt_mode));
	}
	return 1;
}

	void
encrypt_send_support()
{
	if (str_suplen) {
		/*
		 * If the user has requested that decryption start
		 * immediatly, then send a "REQUEST START" before
		 * we negotiate the type.
		 */
		if (!Server && autodecrypt)
			encrypt_send_request_start();
		net_write(str_send, str_suplen);
		printsub('>', &str_send[2], str_suplen - 2);
		str_suplen = 0;
	}
}

	int
EncryptDebug(on)
	int on;
{
	if (on < 0)
		encrypt_debug_mode ^= 1;
	else
		encrypt_debug_mode = on;
	printf("Encryption debugging %s\r\n",
		encrypt_debug_mode ? "enabled" : "disabled");
	return(1);
}

	int
EncryptVerbose(on)
	int on;
{
	if (on < 0)
		encrypt_verbose ^= 1;
	else
		encrypt_verbose = on;
	printf("Encryption %s verbose\r\n",
		encrypt_verbose ? "is" : "is not");
	return(1);
}

	int
EncryptAutoEnc(on)
	int on;
{
	encrypt_auto(on);
	printf("Automatic encryption of output is %s\r\n",
		autoencrypt ? "enabled" : "disabled");
	return(1);
}

	int
EncryptAutoDec(on)
	int on;
{
	decrypt_auto(on);
	printf("Automatic decryption of input is %s\r\n",
		autodecrypt ? "enabled" : "disabled");
	return(1);
}

/*
 * Called when ENCRYPT SUPPORT is received.
 */
	void
encrypt_support(typelist, cnt)
	unsigned char *typelist;
	int cnt;
{
	register int type, use_type = 0;
	Encryptions *ep;

	/*
	 * Forget anything the other side has previously told us.
	 */
	remote_supports_decrypt = 0;

	while (cnt-- > 0) {
		type = *typelist++;