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 1.4 2004/05/20 19:24:42 cpressey 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 static void
  83 ChallengeResponse(challenge, pwHash, response)
  84     u_char *challenge;  /* IN   8 octets */
  85     u_char *pwHash;     /* IN  16 octets */
  86     u_char *response;   /* OUT 24 octets */
  87 {
  88     char    ZPasswordHash[21];
  89
  90     BZERO(ZPasswordHash, sizeof(ZPasswordHash));
  91     BCOPY(pwHash, ZPasswordHash, MD4_SIGNATURE_SIZE);
  92
  93 #if 0
  94     log_packet(ZPasswordHash, sizeof(ZPasswordHash), "ChallengeResponse - ZPasswordHash", LOG_DEBUG);
  95 #endif
  96
  97     DesEncrypt(challenge, ZPasswordHash +  0, response + 0);
  98     DesEncrypt(challenge, ZPasswordHash +  7, response + 8);
  99     DesEncrypt(challenge, ZPasswordHash + 14, response + 16);
 100
 101 #if 0
 102     log_packet(response, 24, "ChallengeResponse - response", LOG_DEBUG);
 103 #endif
 104 }
 105
 106
 107 #ifdef USE_CRYPT
 108 static void
 109 DesEncrypt(clear, key, cipher)
 110     u_char *clear;      /* IN  8 octets */
 111     u_char *key;        /* IN  7 octets */
 112     u_char *cipher;     /* OUT 8 octets */
 113 {
 114     u_char des_key[8];
 115     u_char crypt_key[66];
 116     u_char des_input[66];
 117
 118     MakeKey(key, des_key);
 119
 120     Expand(des_key, crypt_key);
 121     setkey(crypt_key);
 122
 123 #if 0
 124     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
 125                clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
 126 #endif
 127
 128     Expand(clear, des_input);
 129     encrypt(des_input, 0);
 130     Collapse(des_input, cipher);
 131
 132 #if 0
 133     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
 134                cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
 135 #endif
 136 }
 137
 138 #else /* USE_CRYPT */
 139
 140 static void
 141 DesEncrypt(clear, key, cipher)
 142     u_char *clear;      /* IN  8 octets */
 143     u_char *key;        /* IN  7 octets */
 144     u_char *cipher;     /* OUT 8 octets */
 145 {
 146     des_cblock          des_key;
 147     des_key_schedule    key_schedule;
 148
 149     MakeKey(key, des_key);
 150
 151     des_set_key(&des_key, key_schedule);
 152
 153 #if 0
 154     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet input : %02X%02X%02X%02X%02X%02X%02X%02X",
 155                clear[0], clear[1], clear[2], clear[3], clear[4], clear[5], clear[6], clear[7]));
 156 #endif
 157
 158     des_ecb_encrypt((des_cblock *)clear, (des_cblock *)cipher, key_schedule, 1);
 159
 160 #if 0
 161     CHAPDEBUG((LOG_INFO, "DesEncrypt: 8 octet output: %02X%02X%02X%02X%02X%02X%02X%02X",
 162                cipher[0], cipher[1], cipher[2], cipher[3], cipher[4], cipher[5], cipher[6], cipher[7]));
 163 #endif
 164 }
 165
 166 #endif /* USE_CRYPT */
 167
 168
 169 static u_char Get7Bits(input, startBit)
 170     u_char *input;
 171     int startBit;
 172 {
 173     unsigned int word;
 174
 175     word  = (unsigned)input[startBit / 8] << 8;
 176     word |= (unsigned)input[startBit / 8 + 1];
 177
 178     word >>= 15 - (startBit % 8 + 7);
 179
 180     return word & 0xFE;
 181 }
 182
 183 #ifdef USE_CRYPT
 184
 185 /* in == 8-byte string (expanded version of the 56-bit key)
 186  * out == 64-byte string where each byte is either 1 or 0
 187  * Note that the low-order "bit" is always ignored by by setkey()
 188  */
 189 static void Expand(in, out)
 190     u_char *in;
 191     u_char *out;
 192 {
 193         int j, c;
 194         int i;
 195
 196         for(i = 0; i < 64; in++){
 197                 c = *in;
 198                 for(j = 7; j >= 0; j--)
 199                         *out++ = (c >> j) & 01;
 200                 i += 8;
 201         }
 202 }
 203
 204 /* The inverse of Expand
 205  */
 206 static void Collapse(in, out)
 207     u_char *in;
 208     u_char *out;
 209 {
 210         int j;
 211         int i;
 212         unsigned int c;
 213
 214         for (i = 0; i < 64; i += 8, out++) {
 215             c = 0;
 216             for (j = 7; j >= 0; j--, in++)
 217                 c |= *in << j;
 218             *out = c & 0xff;
 219         }
 220 }
 221 #endif
 222
 223 static void MakeKey(key, des_key)
 224     u_char *key;        /* IN  56 bit DES key missing parity bits */
 225     u_char *des_key;    /* OUT 64 bit DES key with parity bits added */
 226 {
 227     des_key[0] = Get7Bits(key,  0);
 228     des_key[1] = Get7Bits(key,  7);
 229     des_key[2] = Get7Bits(key, 14);
 230     des_key[3] = Get7Bits(key, 21);
 231     des_key[4] = Get7Bits(key, 28);
 232     des_key[5] = Get7Bits(key, 35);
 233     des_key[6] = Get7Bits(key, 42);
 234     des_key[7] = Get7Bits(key, 49);
 235
 236 #ifndef USE_CRYPT
 237     des_set_odd_parity((des_cblock *)des_key);
 238 #endif
 239
 240 #if 0
 241     CHAPDEBUG((LOG_INFO, "MakeKey: 56-bit input : %02X%02X%02X%02X%02X%02X%02X",
 242                key[0], key[1], key[2], key[3], key[4], key[5], key[6]));
 243     CHAPDEBUG((LOG_INFO, "MakeKey: 64-bit output: %02X%02X%02X%02X%02X%02X%02X%02X",
 244                des_key[0], des_key[1], des_key[2], des_key[3], des_key[4], des_key[5], des_key[6], des_key[7]));
 245 #endif
 246 }
 247
 248 static void
 249 ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, response)
 250     char *rchallenge;
 251     int rchallenge_len;
 252     char *secret;
 253     int secret_len;
 254     MS_ChapResponse    *response;
 255 {
 256     int                 i;
 257     MD4_CTX             md4Context;
 258     u_char              hash[MD4_SIGNATURE_SIZE];
 259     u_char              unicodePassword[MAX_NT_PASSWORD * 2];
 260
 261     /* Initialize the Unicode version of the secret (== password). */
 262     /* This implicitly supports 8-bit ISO8859/1 characters. */
 263     BZERO(unicodePassword, sizeof(unicodePassword));
 264     for (i = 0; i < secret_len; i++)
 265         unicodePassword[i * 2] = (u_char)secret[i];
 266
 267     MD4Init(&md4Context);
 268     MD4Update(&md4Context, unicodePassword, secret_len * 2);    /* Unicode is 2 bytes/char */
 269
 270     MD4Final(hash, &md4Context);        /* Tell MD4 we're done */
 271
 272     ChallengeResponse(rchallenge, hash, response->NTResp);
 273 }
 274
 275 #ifdef MSLANMAN
 276 static u_char *StdText = (u_char *)"KGS!@#$%"; /* key from rasapi32.dll */
 277
 278 static void
 279 ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, response)
 280     char *rchallenge;
 281     int rchallenge_len;
 282     char *secret;
 283     int secret_len;
 284     MS_ChapResponse     *response;
 285 {
 286     int                 i;
 287     u_char              UcasePassword[MAX_NT_PASSWORD]; /* max is actually 14 */
 288     u_char              PasswordHash[MD4_SIGNATURE_SIZE];
 289
 290     /* LANMan password is case insensitive */
 291     BZERO(UcasePassword, sizeof(UcasePassword));
 292     for (i = 0; i < secret_len; i++)
 293        UcasePassword[i] = (u_char)toupper(secret[i]);
 294     DesEncrypt( StdText, UcasePassword + 0, PasswordHash + 0 );
 295     DesEncrypt( StdText, UcasePassword + 7, PasswordHash + 8 );
 296     ChallengeResponse(rchallenge, PasswordHash, response->LANManResp);
 297 }
 298 #endif
 299
 300 void
 301 ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len)
 302     chap_state *cstate;
 303     char *rchallenge;
 304     int rchallenge_len;
 305     char *secret;
 306     int secret_len;
 307 {
 308     MS_ChapResponse     response;
 309 #ifdef MSLANMAN
 310     extern int ms_lanman;
 311 #endif
 312
 313 #if 0
 314     CHAPDEBUG((LOG_INFO, "ChapMS: secret is '%.*s'", secret_len, secret));
 315 #endif
 316     BZERO(&response, sizeof(response));
 317
 318     /* Calculate both always */
 319     ChapMS_NT(rchallenge, rchallenge_len, secret, secret_len, &response);
 320
 321 #ifdef MSLANMAN
 322     ChapMS_LANMan(rchallenge, rchallenge_len, secret, secret_len, &response);
 323
 324     /* prefered method is set by option  */
 325     response.UseNT = !ms_lanman;
 326 #else
 327     response.UseNT = 1;
 328 #endif
 329
 330     BCOPY(&response, cstate->response, MS_CHAP_RESPONSE_LEN);
 331     cstate->resp_length = MS_CHAP_RESPONSE_LEN;
 332 }
 333
 334 #endif /* CHAPMS */