source/libsmb/ntlmssp_sign.c

   1 /*
   2  *  Unix SMB/CIFS implementation.
   3  *  Version 3.0
   4  *  NTLMSSP Signing routines
   5  *  Copyright (C) Luke Kenneth Casson Leighton 1996-2001
   6  *  Copyright (C) Andrew Bartlett 2003
   7  *
   8  *  This program is free software; you can redistribute it and/or modify
   9  *  it under the terms of the GNU General Public License as published by
  10  *  the Free Software Foundation; either version 2 of the License, or
  11  *  (at your option) any later version.
  12  *
  13  *  This program is distributed in the hope that it will be useful,
  14  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  *  GNU General Public License for more details.
  17  *
  18  *  You should have received a copy of the GNU General Public License
  19  *  along with this program; if not, write to the Free Software Foundation,
  20  *  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  21  */
  22
  23 #include "includes.h"
  24
  25 #define CLI_SIGN "session key to client-to-server signing key magic constant"
  26 #define CLI_SEAL "session key to client-to-server sealing key magic constant"
  27 #define SRV_SIGN "session key to server-to-client signing key magic constant"
  28 #define SRV_SEAL "session key to server-to-client sealing key magic constant"
  29
  30 static void NTLMSSPcalc_ap( unsigned char *hash, unsigned char *data, int len)
  31 {
  32     unsigned char index_i = hash[256];
  33     unsigned char index_j = hash[257];
  34     int ind;
  35
  36     for (ind = 0; ind < len; ind++)
  37     {
  38         unsigned char tc;
  39         unsigned char t;
  40
  41         index_i++;
  42         index_j += hash[index_i];
  43
  44         tc = hash[index_i];
  45         hash[index_i] = hash[index_j];
  46         hash[index_j] = tc;
  47
  48         t = hash[index_i] + hash[index_j];
  49         data[ind] = data[ind] ^ hash[t];
  50     }
  51
  52     hash[256] = index_i;
  53     hash[257] = index_j;
  54 }
  55
  56 static void calc_hash(unsigned char hash[258], unsigned char *k2, int k2l)
  57 {
  58         unsigned char j = 0;
  59         int ind;
  60
  61         for (ind = 0; ind < 256; ind++)
  62         {
  63                 hash[ind] = (unsigned char)ind;
  64         }
  65
  66         for (ind = 0; ind < 256; ind++)
  67         {
  68                 unsigned char tc;
  69
  70                 j += (hash[ind] + k2[ind%k2l]);
  71
  72                 tc = hash[ind];
  73                 hash[ind] = hash[j];
  74                 hash[j] = tc;
  75         }
  76
  77         hash[256] = 0;
  78         hash[257] = 0;
  79 }
  80
  81 static void calc_ntlmv2_hash(unsigned char hash[258], unsigned char digest[16],
  82                              DATA_BLOB session_key,
  83                              const char *constant)
  84 {
  85         struct MD5Context ctx3;
  86
  87         /* NOTE:  This code is currently complate fantasy - it's
  88            got more in common with reality than the previous code
  89            (the LM session key is not the right thing to use) but
  90            it still needs work */
  91
  92         MD5Init(&ctx3);
  93         MD5Update(&ctx3, session_key.data, session_key.length);
  94         MD5Update(&ctx3, (const unsigned char *)constant, strlen(constant)+1);
  95         MD5Final(digest, &ctx3);
  96
  97         calc_hash(hash, digest, 16);
  98 }
  99
 100 enum ntlmssp_direction {
 101         NTLMSSP_SEND,
 102         NTLMSSP_RECEIVE
 103 };
 104
 105 static NTSTATUS ntlmssp_make_packet_signature(NTLMSSP_STATE *ntlmssp_state,
 106                                               const uchar *data, size_t length,
 107                                               enum ntlmssp_direction direction,
 108                                               DATA_BLOB *sig)
 109 {
 110         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 111                 HMACMD5Context ctx;
 112                 uchar seq_num[4];
 113                 uchar digest[16];
 114                 SIVAL(seq_num, 0, ntlmssp_state->ntlmssp_seq_num);
 115
 116                 hmac_md5_init_limK_to_64((const unsigned char *)(ntlmssp_state->send_sign_const), 16, &ctx);
 117                 hmac_md5_update(seq_num, 4, &ctx);
 118                 hmac_md5_update(data, length, &ctx);
 119                 hmac_md5_final(digest, &ctx);
 120
 121                 if (!msrpc_gen(sig, "dBd", NTLMSSP_SIGN_VERSION, digest, 8 /* only copy first 8 bytes */
 122                                , ntlmssp_state->ntlmssp_seq_num)) {
 123                         return NT_STATUS_NO_MEMORY;
 124                 }
 125
 126                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
 127                         switch (direction) {
 128                         case NTLMSSP_SEND:
 129                                 NTLMSSPcalc_ap(ntlmssp_state->send_sign_hash,  sig->data+4, sig->length-4);
 130                                 break;
 131                         case NTLMSSP_RECEIVE:
 132                                 NTLMSSPcalc_ap(ntlmssp_state->recv_sign_hash,  sig->data+4, sig->length-4);
 133                                 break;
 134                         }
 135                 }
 136         } else {
 137                 uint32 crc;
 138                 crc = crc32_calc_buffer((const char *)data, length);
 139                 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmssp_seq_num)) {
 140                         return NT_STATUS_NO_MEMORY;
 141                 }
 142
 143                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 144                              sizeof(ntlmssp_state->ntlmssp_hash));
 145                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
 146         }
 147         return NT_STATUS_OK;
 148 }
 149
 150 NTSTATUS ntlmssp_sign_packet(NTLMSSP_STATE *ntlmssp_state,
 151                                     const uchar *data, size_t length,
 152                                     DATA_BLOB *sig)
 153 {
 154         NTSTATUS nt_status;
 155         if (!ntlmssp_state->session_key.length) {
 156                 DEBUG(3, ("NO session key, cannot check sign packet\n"));
 157                 return NT_STATUS_NO_USER_SESSION_KEY;
 158         }
 159
 160         nt_status = ntlmssp_make_packet_signature(ntlmssp_state, data, length, NTLMSSP_SEND, sig);
 161
 162         /* increment counter on send */
 163         ntlmssp_state->ntlmssp_seq_num++;
 164         return nt_status;
 165 }
 166
 167 /**
 168  * Check the signature of an incoming packet
 169  * @note caller *must* check that the signature is the size it expects
 170  *
 171  */
 172
 173 NTSTATUS ntlmssp_check_packet(NTLMSSP_STATE *ntlmssp_state,
 174                               const uchar *data, size_t length,
 175                               const DATA_BLOB *sig)
 176 {
 177         DATA_BLOB local_sig;
 178         NTSTATUS nt_status;
 179
 180         if (!ntlmssp_state->session_key.length) {
 181                 DEBUG(3, ("NO session key, cannot check packet signature\n"));
 182                 return NT_STATUS_NO_USER_SESSION_KEY;
 183         }
 184
 185         if (sig->length < 8) {
 186                 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
 187                           (unsigned long)sig->length));
 188         }
 189
 190         nt_status = ntlmssp_make_packet_signature(ntlmssp_state, data,
 191                                                   length, NTLMSSP_RECEIVE, &local_sig);
 192
 193         if (!NT_STATUS_IS_OK(nt_status)) {
 194                 DEBUG(0, ("NTLMSSP packet check failed with %s\n", nt_errstr(nt_status)));
 195                 return nt_status;
 196         }
 197
 198         if (memcmp(sig->data+sig->length - 8, local_sig.data+local_sig.length - 8, 8) != 0) {
 199                 DEBUG(5, ("BAD SIG: wanted signature of\n"));
 200                 dump_data(5, (const char *)local_sig.data, local_sig.length);
 201
 202                 DEBUG(5, ("BAD SIG: got signature of\n"));
 203                 dump_data(5, (const char *)(sig->data), sig->length);
 204
 205                 DEBUG(0, ("NTLMSSP packet check failed due to invalid signature!\n"));
 206                 return NT_STATUS_ACCESS_DENIED;
 207         }
 208
 209         /* increment counter on recieive */
 210         ntlmssp_state->ntlmssp_seq_num++;
 211
 212         return NT_STATUS_OK;
 213 }
 214
 215
 216 /**
 217  * Seal data with the NTLMSSP algorithm
 218  *
 219  */
 220
 221 NTSTATUS ntlmssp_seal_packet(NTLMSSP_STATE *ntlmssp_state,
 222                              uchar *data, size_t length,
 223                              DATA_BLOB *sig)
 224 {
 225         if (!ntlmssp_state->session_key.length) {
 226                 DEBUG(3, ("NO session key, cannot seal packet\n"));
 227                 return NT_STATUS_NO_USER_SESSION_KEY;
 228         }
 229
 230         DEBUG(10,("ntlmssp_seal_data: seal\n"));
 231         dump_data_pw("ntlmssp clear data\n", data, length);
 232         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 233                 HMACMD5Context ctx;
 234                 char seq_num[4];
 235                 uchar digest[16];
 236                 SIVAL(seq_num, 0, ntlmssp_state->ntlmssp_seq_num);
 237
 238                 hmac_md5_init_limK_to_64((const unsigned char *)(ntlmssp_state->send_sign_const), 16, &ctx);
 239                 hmac_md5_update((const unsigned char *)seq_num, 4, &ctx);
 240                 hmac_md5_update(data, length, &ctx);
 241                 hmac_md5_final(digest, &ctx);
 242
 243                 if (!msrpc_gen(sig, "dBd", NTLMSSP_SIGN_VERSION, digest, 8 /* only copy first 8 bytes */
 244                                , ntlmssp_state->ntlmssp_seq_num)) {
 245                         return NT_STATUS_NO_MEMORY;
 246                 }
 247
 248                 dump_data_pw("ntlmssp client sealing hash:\n",
 249                              ntlmssp_state->send_seal_hash,
 250                              sizeof(ntlmssp_state->send_seal_hash));
 251                 NTLMSSPcalc_ap(ntlmssp_state->send_seal_hash, data, length);
 252                 dump_data_pw("ntlmssp client signing hash:\n",
 253                              ntlmssp_state->send_sign_hash,
 254                              sizeof(ntlmssp_state->send_sign_hash));
 255                 NTLMSSPcalc_ap(ntlmssp_state->send_sign_hash,  sig->data+4, sig->length-4);
 256         } else {
 257                 uint32 crc;
 258                 crc = crc32_calc_buffer((const char *)data, length);
 259                 if (!msrpc_gen(sig, "dddd", NTLMSSP_SIGN_VERSION, 0, crc, ntlmssp_state->ntlmssp_seq_num)) {
 260                         return NT_STATUS_NO_MEMORY;
 261                 }
 262
 263                 /* The order of these two operations matters - we must first seal the packet,
 264                    then seal the sequence number - this is becouse the ntlmssp_hash is not
 265                    constant, but is is rather updated with each iteration */
 266
 267                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 268                              sizeof(ntlmssp_state->ntlmssp_hash));
 269                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, data, length);
 270
 271                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 272                              sizeof(ntlmssp_state->ntlmssp_hash));
 273                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, sig->data+4, sig->length-4);
 274         }
 275         dump_data_pw("ntlmssp sealed data\n", data, length);
 276
 277         /* increment counter on send */
 278         ntlmssp_state->ntlmssp_seq_num++;
 279
 280         return NT_STATUS_OK;
 281 }
 282
 283 /**
 284  * Unseal data with the NTLMSSP algorithm
 285  *
 286  */
 287
 288 NTSTATUS ntlmssp_unseal_packet(NTLMSSP_STATE *ntlmssp_state,
 289                                       uchar *data, size_t length,
 290                                       DATA_BLOB *sig)
 291 {
 292         if (!ntlmssp_state->session_key.length) {
 293                 DEBUG(3, ("NO session key, cannot unseal packet\n"));
 294                 return NT_STATUS_NO_USER_SESSION_KEY;
 295         }
 296
 297         DEBUG(10,("ntlmssp__unseal_data: seal\n"));
 298         dump_data_pw("ntlmssp sealed data\n", data, length);
 299         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 300                 NTLMSSPcalc_ap(ntlmssp_state->recv_seal_hash, data, length);
 301         } else {
 302                 dump_data_pw("ntlmssp hash:\n", ntlmssp_state->ntlmssp_hash,
 303                              sizeof(ntlmssp_state->ntlmssp_hash));
 304                 NTLMSSPcalc_ap(ntlmssp_state->ntlmssp_hash, data, length);
 305         }
 306         dump_data_pw("ntlmssp clear data\n", data, length);
 307
 308         return ntlmssp_check_packet(ntlmssp_state, data, length, sig);
 309 }
 310
 311 /**
 312    Initialise the state for NTLMSSP signing.
 313 */
 314 NTSTATUS ntlmssp_sign_init(NTLMSSP_STATE *ntlmssp_state)
 315 {
 316         unsigned char p24[24];
 317         ZERO_STRUCT(p24);
 318
 319         DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
 320         debug_ntlmssp_flags(ntlmssp_state->neg_flags);
 321
 322         if (!ntlmssp_state->session_key.length) {
 323                 DEBUG(3, ("NO session key, cannot intialise signing\n"));
 324                 return NT_STATUS_NO_USER_SESSION_KEY;
 325         }
 326
 327         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2)
 328         {
 329                 const char *send_sign_const;
 330                 const char *send_seal_const;
 331                 const char *recv_sign_const;
 332                 const char *recv_seal_const;
 333
 334                 switch (ntlmssp_state->role) {
 335                 case NTLMSSP_CLIENT:
 336                         send_sign_const = CLI_SIGN;
 337                         send_seal_const = CLI_SEAL;
 338                         recv_sign_const = SRV_SIGN;
 339                         recv_seal_const = SRV_SEAL;
 340                         break;
 341                 case NTLMSSP_SERVER:
 342                         send_sign_const = SRV_SIGN;
 343                         send_seal_const = SRV_SEAL;
 344                         recv_sign_const = CLI_SIGN;
 345                         recv_seal_const = CLI_SEAL;
 346                         break;
 347                 default:
 348                         send_sign_const = "unknown role";
 349                         send_seal_const = "unknown role";
 350                         recv_sign_const = "unknown role";
 351                         recv_seal_const = "unknown role";
 352                         break;
 353                 }
 354
 355                 calc_ntlmv2_hash(ntlmssp_state->send_sign_hash,
 356                                  ntlmssp_state->send_sign_const,
 357                                  ntlmssp_state->session_key, send_sign_const);
 358                 dump_data_pw("NTLMSSP send sign hash:\n",
 359                              ntlmssp_state->send_sign_hash,
 360                              sizeof(ntlmssp_state->send_sign_hash));
 361
 362                 calc_ntlmv2_hash(ntlmssp_state->send_seal_hash,
 363                                  ntlmssp_state->send_seal_const,
 364                                  ntlmssp_state->session_key, send_seal_const);
 365                 dump_data_pw("NTLMSSP send sesl hash:\n",
 366                              ntlmssp_state->send_seal_hash,
 367                              sizeof(ntlmssp_state->send_seal_hash));
 368
 369                 calc_ntlmv2_hash(ntlmssp_state->recv_sign_hash,
 370                                  ntlmssp_state->recv_sign_const,
 371                                  ntlmssp_state->session_key, recv_sign_const);
 372                 dump_data_pw("NTLMSSP receive sign hash:\n",
 373                              ntlmssp_state->recv_sign_hash,
 374                              sizeof(ntlmssp_state->recv_sign_hash));
 375
 376                 calc_ntlmv2_hash(ntlmssp_state->recv_seal_hash,
 377                                  ntlmssp_state->recv_seal_const,
 378                                  ntlmssp_state->session_key, recv_seal_const);
 379                 dump_data_pw("NTLMSSP receive seal hash:\n",
 380                              ntlmssp_state->recv_sign_hash,
 381                              sizeof(ntlmssp_state->recv_sign_hash));
 382
 383         }
 384         else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
 385                 if (!ntlmssp_state->session_key.data || ntlmssp_state->session_key.length < 8) {
 386                         /* can't sign or check signatures yet */
 387                         DEBUG(5, ("NTLMSSP Sign/Seal - cannot use LM KEY yet\n"));
 388                         return NT_STATUS_UNSUCCESSFUL;
 389                 }
 390
 391                 DEBUG(5, ("NTLMSSP Sign/Seal - using LM KEY\n"));
 392
 393                 calc_hash(ntlmssp_state->ntlmssp_hash, ntlmssp_state->session_key.data, 8);
 394                 dump_data_pw("NTLMSSP hash:\n", ntlmssp_state->ntlmssp_hash,
 395                              sizeof(ntlmssp_state->ntlmssp_hash));
 396         } else {
 397                 if (!ntlmssp_state->session_key.data || ntlmssp_state->session_key.length < 16) {
 398                         /* can't sign or check signatures yet */
 399                         DEBUG(5, ("NTLMSSP Sign/Seal - cannot use NT KEY yet\n"));
 400                         return NT_STATUS_UNSUCCESSFUL;
 401                 }
 402
 403                 DEBUG(5, ("NTLMSSP Sign/Seal - using NT KEY\n"));
 404
 405                 calc_hash(ntlmssp_state->ntlmssp_hash, ntlmssp_state->session_key.data, 16);
 406                 dump_data_pw("NTLMSSP hash:\n", ntlmssp_state->ntlmssp_hash,
 407                              sizeof(ntlmssp_state->ntlmssp_hash));
 408         }
 409
 410         ntlmssp_state->ntlmssp_seq_num = 0;
 411
 412         return NT_STATUS_OK;
 413 }