GCC Code Coverage Report
Directory: ./ Exec Total Coverage
File: sbin/iked/chap_ms.c Lines: 0 94 0.0 %
Date: 2016-12-06 Branches: 0 14 0.0 %

Line Branch Exec Source
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/*	$OpenBSD: chap_ms.c,v 1.9 2015/08/21 11:59:27 reyk Exp $	*/
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/*
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 * Copyright (c) 2010-2013 Reyk Floeter <reyk@openbsd.org>
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 * Copyright (c) 1997-2001 Brian Somers <brian@Awfulhak.org>
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 * Copyright (c) 1997 Gabor Kincses <gabor@acm.org>
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 * Copyright (c) 1995 Eric Rosenquist
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 *
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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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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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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#include <sys/types.h>
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#include <ctype.h>
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#include <string.h>
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#include <stdio.h>
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#include <openssl/evp.h>
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#include <openssl/des.h>
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#include <openssl/md4.h>
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#include <openssl/md5.h>
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#include <openssl/sha.h>
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#include "chap_ms.h"
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/*
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 * Documentation & specifications:
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 *
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 * MS-CHAP (CHAP80)	RFC2433
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 * MS-CHAP-V2 (CHAP81)	RFC2759
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 * MPPE key management	RFC3079
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 *
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 * Security analysis:
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 * Schneier/Mudge/Wagner, "MS-CHAP-v2", Oct 99
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 * "It is unclear to us why this protocol is so complicated."
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 */
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static uint8_t sha1_pad1[40] = {
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	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
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};
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static uint8_t sha1_pad2[40] = {
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	0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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	0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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	0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2,
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	0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2, 0xf2
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};
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uint8_t		 get7bits(uint8_t *, int);
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void		 mschap_des_addparity(uint8_t *, uint8_t *);
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void		 mschap_des_encrypt(uint8_t *, uint8_t *, uint8_t *);
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void		 mschap_challenge_response(uint8_t *, uint8_t *, uint8_t *);
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uint8_t
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get7bits(uint8_t *in, int start)
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{
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	unsigned int	 word;
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	word = (unsigned int)in[start / 8] << 8;
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	word |= (unsigned int)in[start / 8 + 1];
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	word >>= 15 - (start % 8 + 7);
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	return (word & 0xfe);
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}
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/* IN  56 bit DES key missing parity bits
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   OUT 64 bit DES key with parity bits added */
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void
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mschap_des_addparity(uint8_t *key, uint8_t *des_key)
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{
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	des_key[0] = get7bits(key,  0);
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	des_key[1] = get7bits(key,  7);
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	des_key[2] = get7bits(key, 14);
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	des_key[3] = get7bits(key, 21);
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	des_key[4] = get7bits(key, 28);
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	des_key[5] = get7bits(key, 35);
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	des_key[6] = get7bits(key, 42);
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	des_key[7] = get7bits(key, 49);
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	DES_set_odd_parity((DES_cblock *)des_key);
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}
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void
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mschap_des_encrypt(uint8_t *clear, uint8_t *key, uint8_t *cipher)
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{
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	DES_cblock		des_key;
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	DES_key_schedule	key_schedule;
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	mschap_des_addparity(key, des_key);
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	DES_set_key(&des_key, &key_schedule);
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	DES_ecb_encrypt((DES_cblock *)clear, (DES_cblock *)cipher,
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	    &key_schedule, 1);
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}
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void
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mschap_challenge_response(uint8_t *challenge, uint8_t *pwhash,
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    uint8_t *response)
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{
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	uint8_t		 padpwhash[21 + 1];
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	bzero(&padpwhash, sizeof(padpwhash));
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	memcpy(padpwhash, pwhash, MSCHAP_HASH_SZ);
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	mschap_des_encrypt(challenge, padpwhash + 0, response + 0);
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	mschap_des_encrypt(challenge, padpwhash + 7, response + 8);
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	mschap_des_encrypt(challenge, padpwhash + 14, response + 16);
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}
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void
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mschap_ntpassword_hash(uint8_t *in, int inlen, uint8_t *hash)
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{
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	EVP_MD_CTX	 ctx;
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	unsigned int	 mdlen;
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	EVP_DigestInit(&ctx, EVP_md4());
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	EVP_DigestUpdate(&ctx, in, inlen);
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	EVP_DigestFinal(&ctx, hash, &mdlen);
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}
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void
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mschap_challenge_hash(uint8_t *peer_challenge, uint8_t *auth_challenge,
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    uint8_t *username, int usernamelen, uint8_t *challenge)
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{
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	EVP_MD_CTX	 ctx;
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	uint8_t		 md[SHA_DIGEST_LENGTH];
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	unsigned int	 mdlen;
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	uint8_t		*name;
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	if ((name = strrchr(username, '\\')) == NULL)
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		name = username;
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	else
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		name++;
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	EVP_DigestInit(&ctx, EVP_sha1());
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	EVP_DigestUpdate(&ctx, peer_challenge, MSCHAPV2_CHALLENGE_SZ);
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	EVP_DigestUpdate(&ctx, auth_challenge, MSCHAPV2_CHALLENGE_SZ);
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	EVP_DigestUpdate(&ctx, name, strlen(name));
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	EVP_DigestFinal(&ctx, md, &mdlen);
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	memcpy(challenge, md, MSCHAP_CHALLENGE_SZ);
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}
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void
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mschap_nt_response(uint8_t *auth_challenge, uint8_t *peer_challenge,
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    uint8_t *username, int usernamelen, uint8_t *password, int passwordlen,
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    uint8_t *response)
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{
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	uint8_t		 challenge[MSCHAP_CHALLENGE_SZ];
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	uint8_t		 password_hash[MSCHAP_HASH_SZ];
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	mschap_challenge_hash(peer_challenge, auth_challenge,
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	    username, usernamelen, challenge);
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	mschap_ntpassword_hash(password, passwordlen, password_hash);
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	mschap_challenge_response(challenge, password_hash, response);
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}
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void
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mschap_auth_response(uint8_t *password, int passwordlen,
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    uint8_t *ntresponse, uint8_t *auth_challenge, uint8_t *peer_challenge,
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    uint8_t *username, int usernamelen, uint8_t *auth_response)
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{
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	EVP_MD_CTX	 ctx;
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	uint8_t		 password_hash[MSCHAP_HASH_SZ];
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	uint8_t		 password_hash2[MSCHAP_HASH_SZ];
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	uint8_t		 challenge[MSCHAP_CHALLENGE_SZ];
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	uint8_t		 md[SHA_DIGEST_LENGTH], *ptr;
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	unsigned int	 mdlen;
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	int		 i;
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	const uint8_t	 hex[] = "0123456789ABCDEF";
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	static uint8_t	 magic1[39] = {
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		0x4D, 0x61, 0x67, 0x69, 0x63, 0x20, 0x73, 0x65, 0x72, 0x76,
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		0x65, 0x72, 0x20, 0x74, 0x6F, 0x20, 0x63, 0x6C, 0x69, 0x65,
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		0x6E, 0x74, 0x20, 0x73, 0x69, 0x67, 0x6E, 0x69, 0x6E, 0x67,
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		0x20, 0x63, 0x6F, 0x6E, 0x73, 0x74, 0x61, 0x6E, 0x74
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	};
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	static uint8_t	 magic2[41] = {
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		0x50, 0x61, 0x64, 0x20, 0x74, 0x6F, 0x20, 0x6D, 0x61, 0x6B,
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		0x65, 0x20, 0x69, 0x74, 0x20, 0x64, 0x6F, 0x20, 0x6D, 0x6F,
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		0x72, 0x65, 0x20, 0x74, 0x68, 0x61, 0x6E, 0x20, 0x6F, 0x6E,
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		0x65, 0x20, 0x69, 0x74, 0x65, 0x72, 0x61, 0x74, 0x69, 0x6F,
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		0x6E
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	};
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	mschap_ntpassword_hash(password, passwordlen, password_hash);
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	mschap_ntpassword_hash(password_hash, MSCHAP_HASH_SZ, password_hash2);
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	EVP_DigestInit(&ctx, EVP_sha1());
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	EVP_DigestUpdate(&ctx, password_hash2, sizeof(password_hash2));
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	EVP_DigestUpdate(&ctx, ntresponse, 24);
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	EVP_DigestUpdate(&ctx, magic1, 39);
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	EVP_DigestFinal(&ctx, md, &mdlen);
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	mschap_challenge_hash(peer_challenge, auth_challenge,
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	    username, usernamelen, challenge);
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	EVP_DigestInit(&ctx, EVP_sha1());
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	EVP_DigestUpdate(&ctx, md, sizeof(md));
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	EVP_DigestUpdate(&ctx, challenge, sizeof(challenge));
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	EVP_DigestUpdate(&ctx, magic2, 41);
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	EVP_DigestFinal(&ctx, md, &mdlen);
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	/*
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	 * Encode the value of 'Digest' as "S=" followed by
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	 * 40 ASCII hexadecimal digits and return it in
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	 * AuthenticatorResponse.
232
	 * For example,
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	 *   "S=0123456789ABCDEF0123456789ABCDEF01234567"
234
	 */
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	ptr = auth_response;
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	*ptr++ = 'S';
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	*ptr++ = '=';
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	for (i = 0; i < SHA_DIGEST_LENGTH; i++) {
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		*ptr++ = hex[md[i] >> 4];
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		*ptr++ = hex[md[i] & 0x0f];
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	}
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}
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void
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mschap_masterkey(uint8_t *password_hash2, uint8_t *ntresponse,
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    uint8_t *masterkey)
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{
248
	uint8_t		 md[SHA_DIGEST_LENGTH];
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	unsigned int	 mdlen;
250
	EVP_MD_CTX	 ctx;
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	static uint8_t	 magic1[27] = {
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		0x54, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74,
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		0x68, 0x65, 0x20, 0x4d, 0x50, 0x50, 0x45, 0x20, 0x4d,
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		0x61, 0x73, 0x74, 0x65, 0x72, 0x20, 0x4b, 0x65, 0x79
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	};
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	EVP_DigestInit(&ctx, EVP_sha1());
258
	EVP_DigestUpdate(&ctx, password_hash2, MSCHAP_HASH_SZ);
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	EVP_DigestUpdate(&ctx, ntresponse, 24);
260
	EVP_DigestUpdate(&ctx, magic1, 27);
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	EVP_DigestFinal(&ctx, md, &mdlen);
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	memcpy(masterkey, md, 16);
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}
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void
267
mschap_asymetric_startkey(uint8_t *masterkey, uint8_t *sessionkey,
268
    int sessionkeylen, int issend, int isserver)
269
{
270
	EVP_MD_CTX	 ctx;
271
	uint8_t		 md[SHA_DIGEST_LENGTH];
272
	unsigned int	 mdlen;
273
	uint8_t		*s;
274
	static uint8_t	 magic2[84] = {
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		0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
276
		0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
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		0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
278
		0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20, 0x6b, 0x65, 0x79,
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		0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x73,
280
		0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73, 0x69, 0x64, 0x65,
281
		0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
282
		0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
283
		0x6b, 0x65, 0x79, 0x2e
284
	};
285
	static uint8_t	 magic3[84] = {
286
		0x4f, 0x6e, 0x20, 0x74, 0x68, 0x65, 0x20, 0x63, 0x6c, 0x69,
287
		0x65, 0x6e, 0x74, 0x20, 0x73, 0x69, 0x64, 0x65, 0x2c, 0x20,
288
		0x74, 0x68, 0x69, 0x73, 0x20, 0x69, 0x73, 0x20, 0x74, 0x68,
289
		0x65, 0x20, 0x72, 0x65, 0x63, 0x65, 0x69, 0x76, 0x65, 0x20,
290
		0x6b, 0x65, 0x79, 0x3b, 0x20, 0x6f, 0x6e, 0x20, 0x74, 0x68,
291
		0x65, 0x20, 0x73, 0x65, 0x72, 0x76, 0x65, 0x72, 0x20, 0x73,
292
		0x69, 0x64, 0x65, 0x2c, 0x20, 0x69, 0x74, 0x20, 0x69, 0x73,
293
		0x20, 0x74, 0x68, 0x65, 0x20, 0x73, 0x65, 0x6e, 0x64, 0x20,
294
		0x6b, 0x65, 0x79, 0x2e
295
	};
296
297
	if (issend)
298
		s = isserver ? magic3 : magic2;
299
	else
300
		s = isserver ? magic2 : magic3;
301
302
	EVP_DigestInit(&ctx, EVP_sha1());
303
	EVP_DigestUpdate(&ctx, masterkey, 16);
304
	EVP_DigestUpdate(&ctx, sha1_pad1, 40);
305
	EVP_DigestUpdate(&ctx, s, 84);
306
	EVP_DigestUpdate(&ctx, sha1_pad2, 40);
307
	EVP_DigestFinal(&ctx, md, &mdlen);
308
309
	memcpy(sessionkey, md, sessionkeylen);
310
}
311
312
void
313
mschap_msk(uint8_t *password, int passwordlen,
314
    uint8_t *ntresponse, uint8_t *msk)
315
{
316
	uint8_t		 password_hash[MSCHAP_HASH_SZ];
317
	uint8_t		 password_hash2[MSCHAP_HASH_SZ];
318
	uint8_t		 masterkey[MSCHAP_MASTERKEY_SZ];
319
	uint8_t		 sendkey[MSCHAP_MASTERKEY_SZ];
320
	uint8_t		 recvkey[MSCHAP_MASTERKEY_SZ];
321
322
	mschap_ntpassword_hash(password, passwordlen, password_hash);
323
	mschap_ntpassword_hash(password_hash, MSCHAP_HASH_SZ, password_hash2);
324
325
	mschap_masterkey(password_hash2, ntresponse, masterkey);
326
	mschap_asymetric_startkey(masterkey, recvkey, sizeof(recvkey), 0, 1);
327
	mschap_asymetric_startkey(masterkey, sendkey, sizeof(sendkey), 1, 1);
328
329
	/* 16 bytes receive key + 16 bytes send key + 32 bytes 0 padding */
330
	bzero(msk, MSCHAP_MSK_SZ);
331
	memcpy(msk, &recvkey, sizeof(recvkey));
332
	memcpy(msk + sizeof(recvkey), &sendkey, sizeof(sendkey));
333
}
334
335
void
336
mschap_radiuskey(uint8_t *plain, const uint8_t *crypted,
337
    const uint8_t *authenticator, const uint8_t *secret)
338
{
339
	EVP_MD_CTX	 ctx;
340
	uint8_t		 b[MD5_DIGEST_LENGTH], p[32];
341
	unsigned int	 i, mdlen;
342
343
	EVP_DigestInit(&ctx, EVP_md5());
344
	EVP_DigestUpdate(&ctx, secret, strlen(secret));
345
	EVP_DigestUpdate(&ctx, authenticator, 16);
346
	EVP_DigestUpdate(&ctx, crypted, 2);
347
	EVP_DigestFinal(&ctx, b, &mdlen);
348
349
	for (i = 0; i < mdlen; i++) {
350
		p[i] = b[i] ^ crypted[i+2];
351
	}
352
353
	EVP_DigestInit(&ctx, EVP_md5());
354
	EVP_DigestUpdate(&ctx, secret, strlen(secret));
355
	EVP_DigestUpdate(&ctx, crypted + 2, mdlen);
356
	EVP_DigestFinal(&ctx, b, &mdlen);
357
358
	for (i = 0; i < mdlen; i++) {
359
		p[i+16] = b[i] ^ crypted[i+18];
360
	}
361
362
	memcpy(plain, p+1, 16);
363
}