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