usr.sbin/pppd/chap_ms.c

   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  * $FreeBSD: src/usr.sbin/pppd/chap_ms.c,v 1.8 2000/02/24 21:10:28 markm Exp $
  23  * $DragonFly: src/usr.sbin/pppd/chap_ms.c,v 1.5 2005/11/24 23:42:54 swildner Exp $
  24  */
  25
  26 /*
  27  * Modifications by Lauri Pesonen / lpesonen@clinet.fi, april 1997
  28  *
  29  *   Implemented LANManager type password response to MS-CHAP challenges.
  30  *   Now pppd provides both NT style and LANMan style blocks, and the
  31  *   prefered is set by option "ms-lanman". Default is to use NT.
  32  *   The hash text (StdText) was taken from Win95 RASAPI32.DLL.
  33  *
  34  *   You should also use DOMAIN\\USERNAME as described in README.MSCHAP80
  35  */
  36
  37 #ifdef CHAPMS
  38
  39 #include <stdio.h>
  40 #include <string.h>
  41 #include <ctype.h>
  42 #include <sys/types.h>
  43 #include <sys/time.h>
  44 #include <syslog.h>
  45 #include <unistd.h>
  46 #ifdef HAVE_CRYPT_H
  47 #include <crypt.h>
  48 #endif
  49
  50 #include "pppd.h"
  51 #include "chap.h"
  52 #include "chap_ms.h"
  53 #include "md4.h"
  54
  55 #ifndef USE_CRYPT
  56 #include <openssl/des.h>
  57 #endif
  58
  59 typedef struct {
  60     u_char LANManResp[24];
  61     u_char NTResp[24];
  62     u_char UseNT;               /* If 1, ignore the LANMan response field */
  63 } MS_ChapResponse;
  64 /* We use MS_CHAP_RESPONSE_LEN, rather than sizeof(MS_ChapResponse),
  65    in case this struct gets padded. */
  66
  67
  68 static void     ChallengeResponse(u_char *, u_char *, u_char *);
  69 static void     DesEncrypt(u_char *, u_char *, u_char *);
  70 static void     MakeKey(u_char *, u_char *);
  71 static u_char   Get7Bits(u_char *, int);
  72 static void     ChapMS_NT(char *, int, char *, int, MS_ChapResponse *);
  73 #ifdef MSLANMAN
  74 static void     ChapMS_LANMan(char *, int, char *, int, MS_ChapResponse *);
  75 #endif
  76
  77 #ifdef USE_CRYPT
  78 static void     Expand(u_char *, u_char *);
  79 static void     Collapse(u_char *, u_char *);
  80 #endif
  81
  82 /*
  83  * Parameters:
  84  *      challenge:      IN   8 octets
  85  *      pwHash:         IN  16 octets
  86  *      response:       OUT 24 octets
  87  */
  88 static void
  89 ChallengeResponse(u_char *challenge, u_char *pwHash, u_char *response)
  90 {
  91     char    ZPasswordHash[21];
  92
  93     BZERO(ZPasswordHash, sizeof(ZPasswordHash));
  94     BCOPY(pwHash, ZPasswordHash, MD4_SIGNATURE_SIZE);
  95
  96 #if 0
  97     log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash", LOG_DEBUG);
  98 #endif
  99
 100     DesEncrypt(challenge, ZPasswordHash +  0, response + 0);
 101     DesEncrypt(challenge, ZPasswordHash +  7, response + 8);
 102     DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
 103
 104 #if 0
 105     log_packet(response, 24, "ChallengeResponse - response", LOG_DEBUG);
 106 #endif
 107 }
 108
 109
 110 #ifdef USE_CRYPT
 111 /*
 112  * Parameters:
 113  *      clear:          IN  8 octets
 114  *      key:            IN  7 octets
 115  *      cipher:         OUT 8 octets
 116  */
 117 static void
 118 DesEncrypt(u_char *clear, u_char *key, u_char *cipher)
 119 {
 120     u_char des_key[8];
 121     u_char crypt_key[66];
 122     u_char des_input[66];
 123
 124     MakeKey(key, des_key);
 125
 126     Expand(des_key, crypt_key);
 127     setkey(crypt_key);
 128
 129 #if 0
 130     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
 131                clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
 132 #endif
 133
 134     Expand(clear, des_input);
 135     encrypt(des_input, 0);
 136     Collapse(des_input, cipher);
 137
 138 #if 0
 139     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
 140                cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
 141 #endif
 142 }
 143
 144 #else /* USE_CRYPT */
 145
 146 /*
 147  * Parameters:
 148  *      clear:          IN  8 octets
 149  *      key:            IN  7 octets
 150  *      cipher:         OUT 8 octets
 151  */
 152 static void
 153 DesEncrypt(u_char *clear, u_char *key, u_char *cipher)
 154 {
 155     des_cblock          des_key;
 156     des_key_schedule    key_schedule;
 157
 158     MakeKey(key, des_key);
 159
 160     des_set_key(&des_key, key_schedule);
 161
 162 #if 0
 163     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
 164                clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
 165 #endif
 166
 167     des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
 168
 169 #if 0
 170     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
 171                cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
 172 #endif
 173 }
 174
 175 #endif /* USE_CRYPT */
 176
 177
 178 static u_char
 179 Get7Bits(u_char *input, int startBit)
 180 {
 181     unsigned int word;
 182
 183     word  = (unsigned)input[startBit / 8] << 8;
 184     word |= (unsigned)input[startBit / 8 + 1];
 185
 186     word >>= 15 - (startBit % 8 + 7);
 187
 188     return word & 0xFE;
 189 }
 190
 191 #ifdef USE_CRYPT
 192
 193 /* in == 8-byte string (expanded version of the 56-bit key)
 194  * out == 64-byte string where each byte is either 1 or 0
 195  * Note that the low-order "bit" is always ignored by by setkey()
 196  */
 197 static void
 198 Expand(u_char *in, u_char *out)
 199 {
 200         int j, c;
 201         int i;
 202
 203         for(i = 0; i < 64; in++){
 204                 c = *in;
 205                 for(j = 7; j >= 0; j--)
 206                         *out++ = (c >> j) & 01;
 207                 i += 8;
 208         }
 209 }
 210
 211 /* The inverse of Expand
 212  */
 213 static void
 214 Collapse(u_char *in, u_char *out)
 215 {
 216         int j;
 217         int i;
 218         unsigned int c;
 219
 220         for (i = 0; i < 64; i += 8, out++) {
 221             c = 0;
 222             for (j = 7; j >= 0; j--, in++)
 223                 c |= *in << j;
 224             *out = c & 0xff;
 225         }
 226 }
 227 #endif
 228
 229 /*
 230  * Parameters:
 231  *      IN  56 bit DES key missing parity bits
 232  *      OUT 64 bit DES key with parity bits added
 233  */
 234 static void
 235 MakeKey(u_char *key, u_char *des_key)
 236 {
 237     des_key[0] = Get7Bits(key,  0);
 238     des_key[1] = Get7Bits(key,  7);
 239     des_key[2] = Get7Bits(key, 14);
 240     des_key[3] = Get7Bits(key, 21);
 241     des_key[4] = Get7Bits(key, 28);
 242     des_key[5] = Get7Bits(key, 35);
 243     des_key[6] = Get7Bits(key, 42);
 244     des_key[7] = Get7Bits(key, 49);
 245
 246 #ifndef USE_CRYPT
 247     des_set_odd_parity((des_cblock *)des_key);
 248 #endif
 249
 250 #if 0
 251     CHAPDEBUG((LOG_INFO, "MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X",
 252                key[0], key[1], key[2], key[3], key[4], key[5], key[6]));
 253     CHAPDEBUG((LOG_INFO, "MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X",
 254                des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7]));
 255 #endif
 256 }
 257
 258 static void
 259 ChapMS_NT(char *rchallenge, int rchallenge_len, char *secret, int secret_len,
 260           MS_ChapResponse *response)
 261 {
 262     int                 i;
 263     MD4_CTX             md4Context;
 264     u_char              hash[MD4_SIGNATURE_SIZE];
 265     u_char              unicodePassword[MAX_NT_PASSWORD * 2];
 266
 267     /* Initialize the Unicode version of the secret (== password). */
 268     /* This implicitly supports 8-bit ISO8859/1 characters. */
 269     BZERO(unicodePassword, sizeof(unicodePassword));
 270     for (i = 0; i < secret_len; i++)
 271         unicodePassword[i * 2] = (u_char)secret[i];
 272
 273     MD4Init(&md4Context);
 274     MD4Update(&md4Context, unicodePassword, secret_len * 2);    /* Unicode is 2 bytes/char */
 275
 276     MD4Final(hash, &md4Context);        /* Tell MD4 we're done */
 277
 278     ChallengeResponse(rchallenge, hash, response->NTResp);
 279 }
 280
 281 #ifdef MSLANMAN
 282 static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */
 283
 284 static void
 285 ChapMS_LANMan(char *rchallenge, int rchallenge_len, char *secret,
 286               int secret_len, MS_ChapResponse *response)
 287 {
 288     int                 i;
 289     u_char              UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */
 290     u_char              PasswordHash[MD4_SIGNATURE_SIZE];
 291
 292     /* LANMan password is case insensitive */
 293     BZERO(UcasePassword, sizeof(UcasePassword));
 294     for (i = 0; i < secret_len; i++)
 295        UcasePassword[i] = (u_char)toupper(secret[i]);
 296     DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 );
 297     DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 );
 298     ChallengeResponse(rchallenge, PasswordHash, response->LANManResp);
 299 }
 300 #endif
 301
 302 void
 303 ChapMS(chap_state *cstate, char *rchallenge, int rchallenge_len, char *secret,
 304        int secret_len)
 305 {
 306     MS_ChapResponse     response;
 307 #ifdef MSLANMAN
 308     extern int ms_lanman;
 309 #endif
 310
 311 #if 0
 312     CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret));
 313 #endif
 314     BZERO(&response, sizeof(response));
 315
 316     /* Calculate both always */
 317     ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response);
 318
 319 #ifdef MSLANMAN
 320     ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response);
 321
 322     /* prefered method is set by option  */
 323     response.UseNT = !ms_lanman;
 324 #else
 325     response.UseNT = 1;
 326 #endif
 327
 328     BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
 329     cstate->resp_length = MS_CHAP_RESPONSE_LEN;
 330 }
 331
 332 #endif /* CHAPMS */