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/*
* chap_ms.c - Microsoft MS-CHAP compatible implementation.
*
* Copyright (c) 1995 Eric Rosenquist, Strata Software Limited.
* http://www.strataware.com/
*
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by Eric Rosenquist. The name of the author may not be used to
* endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*/
#ifndef lint
static char rcsid[] = "$Id: chap_ms.c,v 1.2 1997/01/03 20:42:04 millert Exp $";
#endif
#include <stdio.h>
#include <sys/types.h>
#include <sys/time.h>
#include <syslog.h>
#include <md4.h>
#include "pppd.h"
#include "chap.h"
#include "chap_ms.h"
#ifdef CHAPMS
#include <des.h>
typedef struct {
u_char LANManResp[24];
u_char NTResp[24];
u_char UseNT; /* If 1, ignore the LANMan response field */
} MS_ChapResponse;
/* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse),
in case this struct gets padded. */
static void DesEncrypt __P((u_char *, u_char *, u_char *));
static void MakeKey __P((u_char *, u_char *));
static void
ChallengeResponse(challenge, pwHash, response)
u_char *challenge; /* IN 8 octets */
u_char *pwHash; /* IN 16 octets */
u_char *response; /* OUT 24 octets */
{
char ZPasswordHash[21];
BZERO(ZPasswordHash, sizeof(ZPasswordHash));
BCOPY(pwHash, ZPasswordHash, 16);
#if 0
log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash");
#endif
DesEncrypt(challenge, ZPasswordHash + 0, response + 0);
DesEncrypt(challenge, ZPasswordHash + 7, response + 8);
DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
#if 0
log_packet(response, 24, "ChallengeResponse - response");
#endif
}
static void
DesEncrypt(clear, key, cipher)
u_char *clear; /* IN 8 octets */
u_char *key; /* IN 7 octets */
u_char *cipher; /* OUT 8 octets */
{
des_cblock des_key;
des_key_schedule key_schedule;
MakeKey(key, des_key);
des_set_key(&des_key, key_schedule);
#if 0
CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
#endif
des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
#if 0
CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
#endif
}
static u_char Get7Bits(input, startBit)
u_char *input;
int startBit;
{
register unsigned int word;
word = (unsigned)input[startBit / 8] << 8;
word |= (unsigned)input[startBit / 8 + 1];
word >>= 15 - (startBit % 8 + 7);
return word & 0xFE;
}
static void MakeKey(key, des_key)
u_char *key; /* IN 56 bit DES key missing parity bits */
u_char *des_key; /* OUT 64 bit DES key with parity bits added */
{
des_key[0] = Get7Bits(key, 0);
des_key[1] = Get7Bits(key, 7);
des_key[2] = Get7Bits(key, 14);
des_key[3] = Get7Bits(key, 21);
des_key[4] = Get7Bits(key, 28);
des_key[5] = Get7Bits(key, 35);
des_key[6] = Get7Bits(key, 42);
des_key[7] = Get7Bits(key, 49);
des_set_odd_parity((des_cblock *)des_key);
#if 0
CHAPDEBUG((LOG_INFO, "MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X",
key[0], key[1], key[2], key[3], key[4], key[5], key[6]));
CHAPDEBUG((LOG_INFO, "MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X",
des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7]));
#endif
}
#endif /* CHAPMS */
void
ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len)
chap_state *cstate;
char *rchallenge;
int rchallenge_len;
char *secret;
int secret_len;
{
#ifdef CHAPMS
int i;
MD4_CTX md4Context;
MS_ChapResponse response;
u_char unicodePassword[MAX_NT_PASSWORD * 2];
u_char digest[16];
#if 0
CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret));
#endif
BZERO(&response, sizeof(response));
/* Initialize the Unicode version of the secret (== password). */
/* This implicitly supports 8-bit ISO8859/1 characters. */
BZERO(unicodePassword, sizeof(unicodePassword));
for (i = 0; i < secret_len; i++)
unicodePassword[i * 2] = (u_char)secret[i];
MD4Init(&md4Context);
MD4Update(&md4Context, unicodePassword, secret_len * 2 * 8); /* Unicode is 2 bytes/char, *8 for bit count */
MD4Final(digest, &md4Context); /* Tell MD4 we're done */
ChallengeResponse(rchallenge, (char *)digest, response.NTResp);
response.UseNT = 1;
BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
cstate->resp_length = MS_CHAP_RESPONSE_LEN;
#endif /* CHAPMS */
}
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