1 /* 2 * chap_ms.c - Microsoft MS-CHAP compatible implementation. 3 * 4 * Copyright (c) 1995 Eric Rosenquist, Strata Software Limited. 5 * http://www.strataware.com/ 6 * 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms are permitted 10 * provided that the above copyright notice and this paragraph are 11 * duplicated in all such forms and that any documentation, 12 * advertising materials, and other materials related to such 13 * distribution and use acknowledge that the software was developed 14 * by Eric Rosenquist. The name of the author may not be used to 15 * endorse or promote products derived from this software without 16 * specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 20 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 21 * 22 * $Id: chap_ms.c,v 1.5.4.3 1998/05/01 19:24:07 brian Exp $ 23 * 24 */ 25 26 #include <sys/types.h> 27 28 #include <des.h> 29 #include <string.h> 30 31 #include "chap_ms.h" 32 33 /* unused, for documentation only */ 34 /* only NTResp is filled in for FreeBSD */ 35 struct MS_ChapResponse { 36 u_char LANManResp[24]; 37 u_char NTResp[24]; 38 u_char UseNT; /* If 1, ignore the LANMan response field */ 39 }; 40 41 static void DesEncrypt(u_char *, u_char *, u_char *); 42 static void MakeKey(u_char *, u_char *); 43 44 static void /* IN 8 octets IN 16 octets OUT 24 octets */ 45 ChallengeResponse(u_char *challenge, u_char *pwHash, u_char *response) 46 { 47 char ZPasswordHash[21]; 48 49 memset(ZPasswordHash, '\0', sizeof ZPasswordHash); 50 memcpy(ZPasswordHash, pwHash, 16); 51 52 DesEncrypt(challenge, ZPasswordHash + 0, response + 0); 53 DesEncrypt(challenge, ZPasswordHash + 7, response + 8); 54 DesEncrypt(challenge, ZPasswordHash + 14, response + 16); 55 } 56 57 static void /* IN 8 octets IN 7 octest OUT 8 octets */ 58 DesEncrypt(u_char *clear, u_char *key, u_char *cipher) 59 { 60 des_cblock des_key; 61 des_key_schedule key_schedule; 62 63 MakeKey(key, des_key); 64 des_set_key(&des_key, key_schedule); 65 des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1); 66 } 67 68 static u_char Get7Bits(u_char *input, int startBit) 69 { 70 register unsigned int word; 71 72 word = (unsigned)input[startBit / 8] << 8; 73 word |= (unsigned)input[startBit / 8 + 1]; 74 75 word >>= 15 - (startBit % 8 + 7); 76 77 return word & 0xFE; 78 } 79 80 /* IN 56 bit DES key missing parity bits 81 OUT 64 bit DES key with parity bits added */ 82 static void MakeKey(u_char *key, u_char *des_key) 83 { 84 des_key[0] = Get7Bits(key, 0); 85 des_key[1] = Get7Bits(key, 7); 86 des_key[2] = Get7Bits(key, 14); 87 des_key[3] = Get7Bits(key, 21); 88 des_key[4] = Get7Bits(key, 28); 89 des_key[5] = Get7Bits(key, 35); 90 des_key[6] = Get7Bits(key, 42); 91 des_key[7] = Get7Bits(key, 49); 92 93 des_set_odd_parity((des_cblock *)des_key); 94 } 95 96 /* passwordHash 16-bytes MD4 hashed password 97 challenge 8-bytes peer CHAP challenge 98 since passwordHash is in a 24-byte buffer, response is written in there */ 99 void 100 chap_MS(char *passwordHash, char *challenge, int challenge_len) 101 { 102 u_char response[24]; 103 104 ChallengeResponse(challenge, passwordHash, response); 105 memcpy(passwordHash, response, 24); 106 passwordHash += 24; 107 *passwordHash = 1; 108 } 109