/* * 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. * * $Id: chap_ms.c,v 1.5.4.3 1998/05/01 19:24:07 brian Exp $ * */ #include #include #include #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 void DesEncrypt(u_char *, u_char *, u_char *); static void MakeKey(u_char *, u_char *); 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); } 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 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); } /* 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 chap_MS(char *passwordHash, char *challenge, int challenge_len) { u_char response[24]; ChallengeResponse(challenge, passwordHash, response); memcpy(passwordHash, response, 24); passwordHash += 24; *passwordHash = 1; }