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/*
* chap_ms.c - Microsoft MS-CHAP (NT only) 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.
*
* $FreeBSD$
*
*/
#include <sys/types.h>
#include <ctype.h>
#include <des.h>
#include <string.h>
#include "chap_ms.h"
/* unused, for documentation only */
/* only NTResp is filled in for FreeBSD */
struct MS_ChapResponse {
u_char LANManResp[24];
u_char NTResp[24];
u_char UseNT; /* If 1, ignore the LANMan response field */
};
static u_char Get7Bits(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;
}
/* IN 56 bit DES key missing parity bits
OUT 64 bit DES key with parity bits added */
static void MakeKey(u_char *key, u_char *des_key)
{
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);
}
static void /* IN 8 octets IN 7 octest OUT 8 octets */
DesEncrypt(u_char *clear, u_char *key, u_char *cipher)
{
des_cblock des_key;
des_key_schedule key_schedule;
MakeKey(key, des_key);
des_set_key(&des_key, key_schedule);
des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
}
static void /* IN 8 octets IN 16 octets OUT 24 octets */
ChallengeResponse(u_char *challenge, u_char *pwHash, u_char *response)
{
char ZPasswordHash[21];
memset(ZPasswordHash, '\0', sizeof ZPasswordHash);
memcpy(ZPasswordHash, pwHash, 16);
DesEncrypt(challenge, ZPasswordHash + 0, response + 0);
DesEncrypt(challenge, ZPasswordHash + 7, response + 8);
DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
}
/* passwordHash 16-bytes MD4 hashed password
challenge 8-bytes peer CHAP challenge
since passwordHash is in a 24-byte buffer, response is written in there */
void
mschap_NT(char *passwordHash, char *challenge)
{
u_char response[24];
ChallengeResponse(challenge, passwordHash, response);
memcpy(passwordHash, response, 24);
passwordHash[24] = 1; /* NT-style response */
}
void
mschap_LANMan(char *digest, char *challenge, char *secret)
{
static u_char salt[] = "KGS!@#$%"; /* RASAPI32.dll */
char SECRET[14], *ptr, *end;
u_char hash[16];
end = SECRET + sizeof SECRET;
for (ptr = SECRET; *secret && ptr < end; ptr++, secret++)
*ptr = toupper(*secret);
if (ptr < end)
memset(ptr, '\0', end - ptr);
DesEncrypt(salt, SECRET, hash);
DesEncrypt(salt, SECRET + 7, hash + 8);
ChallengeResponse(challenge, hash, digest);
}
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