1 | /* |
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2 | * chap_ms.c - Microsoft MS-CHAP compatible implementation. |
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3 | * |
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4 | * Copyright (c) 1995 Eric Rosenquist, Strata Software Limited. |
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5 | * http://www.strataware.com/ |
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6 | * |
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7 | * All rights reserved. |
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8 | * |
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9 | * Redistribution and use in source and binary forms are permitted |
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10 | * provided that the above copyright notice and this paragraph are |
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11 | * duplicated in all such forms and that any documentation, |
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12 | * advertising materials, and other materials related to such |
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13 | * distribution and use acknowledge that the software was developed |
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14 | * by Eric Rosenquist. The name of the author may not be used to |
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15 | * endorse or promote products derived from this software without |
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16 | * specific prior written permission. |
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17 | * |
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18 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR |
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19 | * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED |
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20 | * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
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21 | */ |
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22 | |
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23 | /* |
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24 | * Modifications by Lauri Pesonen / lpesonen@clinet.fi, april 1997 |
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25 | * |
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26 | * Implemented LANManager type password response to MS-CHAP challenges. |
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27 | * Now pppd provides both NT style and LANMan style blocks, and the |
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28 | * prefered is set by option "ms-lanman". Default is to use NT. |
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29 | * The hash text (StdText) was taken from Win95 RASAPI32.DLL. |
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30 | * |
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31 | * You should also use DOMAIN\\USERNAME as described in README.MSCHAP80 |
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32 | */ |
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33 | |
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34 | #ifndef lint |
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35 | /* static char rcsid[] = "$Id$"; */ |
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36 | #endif |
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37 | |
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38 | #ifdef CHAPMS |
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39 | |
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40 | #include <stdio.h> |
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41 | #include <string.h> |
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42 | #include <ctype.h> |
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43 | #include <sys/types.h> |
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44 | #include <sys/time.h> |
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45 | #include <syslog.h> |
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46 | #include <unistd.h> |
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47 | #ifdef HAVE_CRYPT_H |
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48 | #include <crypt.h> |
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49 | #endif |
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50 | |
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51 | #include "pppd.h" |
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52 | #include "chap.h" |
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53 | #include "chap_ms.h" |
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54 | #include "md4.h" |
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55 | |
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56 | #ifndef USE_CRYPT |
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57 | #include <des.h> |
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58 | #endif |
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59 | |
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60 | typedef struct { |
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61 | u_char LANManResp[24]; |
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62 | u_char NTResp[24]; |
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63 | u_char UseNT; /* If 1, ignore the LANMan response field */ |
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64 | } MS_ChapResponse; |
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65 | /* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse), |
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66 | in case this struct gets padded. */ |
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67 | |
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68 | |
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69 | static void ChallengeResponse __P((u_char *, u_char *, u_char *)); |
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70 | static void DesEncrypt __P((u_char *, u_char *, u_char *)); |
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71 | static void MakeKey __P((u_char *, u_char *)); |
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72 | static u_char Get7Bits __P((u_char *, int)); |
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73 | static void ChapMS_NT __P((char *, int, char *, int, MS_ChapResponse *)); |
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74 | #ifdef MSLANMAN |
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75 | static void ChapMS_LANMan __P((char *, int, char *, int, MS_ChapResponse *)); |
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76 | #endif |
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77 | |
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78 | #ifdef USE_CRYPT |
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79 | static void Expand __P((u_char *, u_char *)); |
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80 | static void Collapse __P((u_char *, u_char *)); |
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81 | #endif |
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82 | |
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83 | static void |
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84 | ChallengeResponse(challenge, pwHash, response) |
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85 | u_char *challenge; /* IN 8 octets */ |
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86 | u_char *pwHash; /* IN 16 octets */ |
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87 | u_char *response; /* OUT 24 octets */ |
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88 | { |
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89 | char ZPasswordHash[21]; |
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90 | |
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91 | BZERO(ZPasswordHash, sizeof(ZPasswordHash)); |
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92 | BCOPY(pwHash, ZPasswordHash, MD4_SIGNATURE_SIZE); |
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93 | |
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94 | #if 0 |
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95 | log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash", LOG_DEBUG); |
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96 | #endif |
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97 | |
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98 | DesEncrypt(challenge, ZPasswordHash + 0, response + 0); |
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99 | DesEncrypt(challenge, ZPasswordHash + 7, response + 8); |
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100 | DesEncrypt(challenge, ZPasswordHash + 14, response + 16); |
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101 | |
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102 | #if 0 |
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103 | log_packet(response, 24, "ChallengeResponse - response", LOG_DEBUG); |
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104 | #endif |
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105 | } |
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106 | |
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107 | |
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108 | #ifdef USE_CRYPT |
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109 | static void |
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110 | DesEncrypt(clear, key, cipher) |
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111 | u_char *clear; /* IN 8 octets */ |
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112 | u_char *key; /* IN 7 octets */ |
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113 | u_char *cipher; /* OUT 8 octets */ |
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114 | { |
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115 | u_char des_key[8]; |
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116 | u_char crypt_key[66]; |
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117 | u_char des_input[66]; |
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118 | |
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119 | MakeKey(key, des_key); |
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120 | |
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121 | Expand(des_key, crypt_key); |
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122 | setkey(crypt_key); |
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123 | |
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124 | #if 0 |
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125 | CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X", |
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126 | clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7])); |
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127 | #endif |
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128 | |
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129 | Expand(clear, des_input); |
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130 | encrypt(des_input, 0); |
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131 | Collapse(des_input, cipher); |
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132 | |
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133 | #if 0 |
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134 | CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X", |
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135 | cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7])); |
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136 | #endif |
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137 | } |
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138 | |
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139 | #else /* USE_CRYPT */ |
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140 | |
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141 | static void |
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142 | DesEncrypt(clear, key, cipher) |
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143 | u_char *clear; /* IN 8 octets */ |
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144 | u_char *key; /* IN 7 octets */ |
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145 | u_char *cipher; /* OUT 8 octets */ |
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146 | { |
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147 | des_cblock des_key; |
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148 | des_key_schedule key_schedule; |
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149 | |
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150 | MakeKey(key, des_key); |
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151 | |
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152 | des_set_key(&des_key, key_schedule); |
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153 | |
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154 | #if 0 |
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155 | CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X", |
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156 | clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7])); |
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157 | #endif |
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158 | |
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159 | des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1); |
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160 | |
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161 | #if 0 |
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162 | CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X", |
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163 | cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7])); |
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164 | #endif |
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165 | } |
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166 | |
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167 | #endif /* USE_CRYPT */ |
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168 | |
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169 | |
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170 | static u_char Get7Bits(input, startBit) |
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171 | u_char *input; |
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172 | int startBit; |
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173 | { |
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174 | register unsigned int word; |
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175 | |
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176 | word = (unsigned)input[startBit / 8] << 8; |
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177 | word |= (unsigned)input[startBit / 8 + 1]; |
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178 | |
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179 | word >>= 15 - (startBit % 8 + 7); |
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180 | |
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181 | return word & 0xFE; |
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182 | } |
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183 | |
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184 | #ifdef USE_CRYPT |
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185 | |
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186 | /* in == 8-byte string (expanded version of the 56-bit key) |
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187 | * out == 64-byte string where each byte is either 1 or 0 |
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188 | * Note that the low-order "bit" is always ignored by by setkey() |
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189 | */ |
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190 | static void Expand(in, out) |
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191 | u_char *in; |
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192 | u_char *out; |
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193 | { |
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194 | int j, c; |
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195 | int i; |
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196 | |
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197 | for(i = 0; i < 64; in++){ |
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198 | c = *in; |
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199 | for(j = 7; j >= 0; j--) |
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200 | *out++ = (c >> j) & 01; |
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201 | i += 8; |
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202 | } |
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203 | } |
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204 | |
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205 | /* The inverse of Expand |
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206 | */ |
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207 | static void Collapse(in, out) |
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208 | u_char *in; |
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209 | u_char *out; |
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210 | { |
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211 | int j; |
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212 | int i; |
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213 | unsigned int c; |
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214 | |
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215 | for (i = 0; i < 64; i += 8, out++) { |
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216 | c = 0; |
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217 | for (j = 7; j >= 0; j--, in++) |
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218 | c |= *in << j; |
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219 | *out = c & 0xff; |
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220 | } |
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221 | } |
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222 | #endif |
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223 | |
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224 | static void MakeKey(key, des_key) |
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225 | u_char *key; /* IN 56 bit DES key missing parity bits */ |
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226 | u_char *des_key; /* OUT 64 bit DES key with parity bits added */ |
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227 | { |
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228 | des_key[0] = Get7Bits(key, 0); |
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229 | des_key[1] = Get7Bits(key, 7); |
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230 | des_key[2] = Get7Bits(key, 14); |
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231 | des_key[3] = Get7Bits(key, 21); |
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232 | des_key[4] = Get7Bits(key, 28); |
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233 | des_key[5] = Get7Bits(key, 35); |
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234 | des_key[6] = Get7Bits(key, 42); |
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235 | des_key[7] = Get7Bits(key, 49); |
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236 | |
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237 | #ifndef USE_CRYPT |
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238 | des_set_odd_parity((des_cblock *)des_key); |
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239 | #endif |
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240 | |
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241 | #if 0 |
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242 | CHAPDEBUG((LOG_INFO, "MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X", |
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243 | key[0], key[1], key[2], key[3], key[4], key[5], key[6])); |
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244 | CHAPDEBUG((LOG_INFO, "MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X", |
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245 | des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7])); |
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246 | #endif |
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247 | } |
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248 | |
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249 | static void |
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250 | ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, response) |
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251 | char *rchallenge; |
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252 | int rchallenge_len; |
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253 | char *secret; |
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254 | int secret_len; |
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255 | MS_ChapResponse *response; |
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256 | { |
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257 | int i; |
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258 | MD4_CTX md4Context; |
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259 | u_char hash[MD4_SIGNATURE_SIZE]; |
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260 | u_char unicodePassword[MAX_NT_PASSWORD * 2]; |
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261 | |
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262 | /* Initialize the Unicode version of the secret (== password). */ |
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263 | /* This implicitly supports 8-bit ISO8859/1 characters. */ |
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264 | BZERO(unicodePassword, sizeof(unicodePassword)); |
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265 | for (i = 0; i < secret_len; i++) |
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266 | unicodePassword[i * 2] = (u_char)secret[i]; |
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267 | |
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268 | MD4Init(&md4Context); |
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269 | MD4Update(&md4Context, unicodePassword, secret_len * 2 * 8); /* Unicode is 2 bytes/char, *8 for bit count */ |
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270 | |
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271 | MD4Final(hash, &md4Context); /* Tell MD4 we're done */ |
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272 | |
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273 | ChallengeResponse(rchallenge, hash, response->NTResp); |
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274 | } |
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275 | |
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276 | #ifdef MSLANMAN |
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277 | static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */ |
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278 | |
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279 | static void |
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280 | ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, response) |
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281 | char *rchallenge; |
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282 | int rchallenge_len; |
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283 | char *secret; |
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284 | int secret_len; |
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285 | MS_ChapResponse *response; |
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286 | { |
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287 | int i; |
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288 | u_char UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */ |
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289 | u_char PasswordHash[MD4_SIGNATURE_SIZE]; |
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290 | |
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291 | /* LANMan password is case insensitive */ |
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292 | BZERO(UcasePassword, sizeof(UcasePassword)); |
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293 | for (i = 0; i < secret_len; i++) |
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294 | UcasePassword[i] = (u_char)toupper(secret[i]); |
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295 | DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 ); |
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296 | DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 ); |
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297 | ChallengeResponse(rchallenge, PasswordHash, response->LANManResp); |
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298 | } |
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299 | #endif |
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300 | |
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301 | void |
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302 | ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len) |
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303 | chap_state *cstate; |
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304 | char *rchallenge; |
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305 | int rchallenge_len; |
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306 | char *secret; |
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307 | int secret_len; |
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308 | { |
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309 | MS_ChapResponse response; |
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310 | #ifdef MSLANMAN |
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311 | extern int ms_lanman; |
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312 | #endif |
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313 | |
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314 | #if 0 |
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315 | CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret)); |
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316 | #endif |
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317 | BZERO(&response, sizeof(response)); |
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318 | |
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319 | /* Calculate both always */ |
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320 | ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response); |
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321 | |
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322 | #ifdef MSLANMAN |
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323 | ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response); |
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324 | |
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325 | /* prefered method is set by option */ |
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326 | response.UseNT = !ms_lanman; |
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327 | #else |
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328 | response.UseNT = 1; |
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329 | #endif |
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330 | |
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331 | BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN); |
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332 | cstate->resp_length = MS_CHAP_RESPONSE_LEN; |
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333 | } |
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334 | |
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335 | #endif /* CHAPMS */ |
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