telnetd/libtelnet/encrypt.h
nsayer 0f2c0f75fe Add SRA authentication to src/crypto/telnet.
SRA does a Diffie-Hellmen exchange and then DES-encrypts the
authentication data. If the authentication is successful, it also
sets up a session key for DES encryption.

SRA was originally developed at Texas A&M University.

This code is probably export restricted (despite the fact that I
originally found it at a University in Germany).

SRA is not perfect. It is vulnerable to monkey-in-the-middle attacks
and does not use tremendously large DH constants (and thus an individual
exchange probably could be factored in a few days on modern CPU
horsepower). It does not, however, require any changes in user or
administrative behavior and foils session hijacking and sniffing.
The goal of this commit is that telnet and telnetd end up in the DES
distribution and that therefore an encrypted session telnet becomes
standard issue for FreeBSD.


git-svn-id: http://svn0.us-east.freebsd.org/base/head/contrib/telnet@49887 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
1999-08-16 11:24:29 +00:00

114 lines
4.1 KiB
C

/*-
* 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.
*
* @(#)encrypt.h 8.1 (Berkeley) 6/4/93
*/
/*
* 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.
*/
#ifdef ENCRYPTION
# ifndef __ENCRYPTION__
# define __ENCRYPTION__
#define DIR_DECRYPT 1
#define DIR_ENCRYPT 2
#include <des.h>
typedef unsigned char Block[8];
typedef unsigned char *BlockT;
#if 0
typedef struct { Block __; } Schedule[16];
#else
#define Schedule des_key_schedule
#endif
#define VALIDKEY(key) ( key[0] | key[1] | key[2] | key[3] | \
key[4] | key[5] | key[6] | key[7])
#define SAMEKEY(k1, k2) (!bcmp((void *)k1, (void *)k2, sizeof(Block)))
typedef struct {
short type;
int length;
unsigned char *data;
} Session_Key;
# if !defined(P)
# ifdef __STDC__
# define P(x) x
# else
# define P(x) ()
# endif
# endif
typedef struct {
char *name;
int type;
void (*output) P((unsigned char *, int));
int (*input) P((int));
void (*init) P((int));
int (*start) P((int, int));
int (*is) P((unsigned char *, int));
int (*reply) P((unsigned char *, int));
void (*session) P((Session_Key *, int));
int (*keyid) P((int, unsigned char *, int *));
void (*printsub) P((unsigned char *, int, unsigned char *, int));
} Encryptions;
#define SK_DES 1 /* Matched Kerberos v5 KEYTYPE_DES */
#include "enc-proto.h"
extern int encrypt_debug_mode;
extern int (*decrypt_input) P((int));
extern void (*encrypt_output) P((unsigned char *, int));
# endif /* __ENCRYPTION__ */
#endif /* ENCRYPTION */