auth/ntlmssp/ntlmssp_sign.c

   1 /*
   2  *  Unix SMB/CIFS implementation.
   3  *  Version 3.0
   4  *  NTLMSSP Signing routines
   5  *  Copyright (C) Andrew Bartlett 2003-2005
   6  *
   7  *  This program is free software; you can redistribute it and/or modify
   8  *  it under the terms of the GNU General Public License as published by
   9  *  the Free Software Foundation; either version 3 of the License, or
  10  *  (at your option) any later version.
  11  *
  12  *  This program is distributed in the hope that it will be useful,
  13  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *  GNU General Public License for more details.
  16  *
  17  *  You should have received a copy of the GNU General Public License
  18  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  19  */
  20
  21 #include "includes.h"
  22 #include "../auth/ntlmssp/ntlmssp.h"
  23 #include "../libcli/auth/libcli_auth.h"
  24 #include "../lib/crypto/md5.h"
  25 #include "../lib/crypto/hmacmd5.h"
  26 #include "../lib/crypto/crc32.h"
  27 #include "../auth/ntlmssp/ntlmssp_private.h"
  28
  29 #define CLI_SIGN "session key to client-to-server signing key magic constant"
  30 #define CLI_SEAL "session key to client-to-server sealing key magic constant"
  31 #define SRV_SIGN "session key to server-to-client signing key magic constant"
  32 #define SRV_SEAL "session key to server-to-client sealing key magic constant"
  33
  34 /**
  35  * Some notes on the NTLM2 code:
  36  *
  37  * NTLM2 is a AEAD system.  This means that the data encrypted is not
  38  * all the data that is signed.  In DCE-RPC case, the headers of the
  39  * DCE-RPC packets are also signed.  This prevents some of the
  40  * fun-and-games one might have by changing them.
  41  *
  42  */
  43
  44 static void dump_arc4_state(const char *description,
  45                             struct arcfour_state *state)
  46 {
  47         dump_data_pw(description, state->sbox, sizeof(state->sbox));
  48 }
  49
  50 static void calc_ntlmv2_key(uint8_t subkey[16],
  51                             DATA_BLOB session_key,
  52                             const char *constant)
  53 {
  54         struct MD5Context ctx3;
  55         MD5Init(&ctx3);
  56         MD5Update(&ctx3, session_key.data, session_key.length);
  57         MD5Update(&ctx3, (const uint8_t *)constant, strlen(constant)+1);
  58         MD5Final(subkey, &ctx3);
  59 }
  60
  61 enum ntlmssp_direction {
  62         NTLMSSP_SEND,
  63         NTLMSSP_RECEIVE
  64 };
  65
  66 static NTSTATUS ntlmssp_make_packet_signature(struct ntlmssp_state *ntlmssp_state,
  67                                               TALLOC_CTX *sig_mem_ctx,
  68                                               const uint8_t *data, size_t length,
  69                                               const uint8_t *whole_pdu, size_t pdu_length,
  70                                               enum ntlmssp_direction direction,
  71                                               DATA_BLOB *sig, bool encrypt_sig)
  72 {
  73         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
  74                 HMACMD5Context ctx;
  75                 uint8_t digest[16];
  76                 uint8_t seq_num[4];
  77
  78                 *sig = data_blob_talloc(sig_mem_ctx, NULL, NTLMSSP_SIG_SIZE);
  79                 if (!sig->data) {
  80                         return NT_STATUS_NO_MEMORY;
  81                 }
  82
  83                 switch (direction) {
  84                 case NTLMSSP_SEND:
  85                         DEBUG(100,("ntlmssp_make_packet_signature: SEND seq = %u, len = %u, pdu_len = %u\n",
  86                                 ntlmssp_state->crypt->ntlm2.sending.seq_num,
  87                                 (unsigned int)length,
  88                                 (unsigned int)pdu_length));
  89
  90                         SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.sending.seq_num);
  91                         ntlmssp_state->crypt->ntlm2.sending.seq_num++;
  92                         hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.sending.sign_key, 16, &ctx);
  93                         break;
  94                 case NTLMSSP_RECEIVE:
  95
  96                         DEBUG(100,("ntlmssp_make_packet_signature: RECV seq = %u, len = %u, pdu_len = %u\n",
  97                                 ntlmssp_state->crypt->ntlm2.receiving.seq_num,
  98                                 (unsigned int)length,
  99                                 (unsigned int)pdu_length));
 100
 101                         SIVAL(seq_num, 0, ntlmssp_state->crypt->ntlm2.receiving.seq_num);
 102                         ntlmssp_state->crypt->ntlm2.receiving.seq_num++;
 103                         hmac_md5_init_limK_to_64(ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16, &ctx);
 104                         break;
 105                 }
 106
 107                 dump_data_pw("pdu data ", whole_pdu, pdu_length);
 108
 109                 hmac_md5_update(seq_num, sizeof(seq_num), &ctx);
 110                 hmac_md5_update(whole_pdu, pdu_length, &ctx);
 111                 hmac_md5_final(digest, &ctx);
 112
 113                 if (encrypt_sig && (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH)) {
 114                         switch (direction) {
 115                         case NTLMSSP_SEND:
 116                                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
 117                                                    digest, 8);
 118                                 break;
 119                         case NTLMSSP_RECEIVE:
 120                                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
 121                                                    digest, 8);
 122                                 break;
 123                         }
 124                 }
 125
 126                 SIVAL(sig->data, 0, NTLMSSP_SIGN_VERSION);
 127                 memcpy(sig->data + 4, digest, 8);
 128                 memcpy(sig->data + 12, seq_num, 4);
 129
 130                 dump_data_pw("ntlmssp v2 sig ", sig->data, sig->length);
 131
 132         } else {
 133                 NTSTATUS status;
 134                 uint32_t crc;
 135
 136                 crc = crc32_calc_buffer(data, length);
 137
 138                 status = msrpc_gen(sig_mem_ctx,
 139                                sig, "dddd",
 140                                NTLMSSP_SIGN_VERSION, 0, crc,
 141                                ntlmssp_state->crypt->ntlm.seq_num);
 142                 if (!NT_STATUS_IS_OK(status)) {
 143                         return status;
 144                 }
 145
 146                 ntlmssp_state->crypt->ntlm.seq_num++;
 147
 148                 dump_arc4_state("ntlmssp hash: \n",
 149                                 &ntlmssp_state->crypt->ntlm.seal_state);
 150                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
 151                                    sig->data+4, sig->length-4);
 152         }
 153         return NT_STATUS_OK;
 154 }
 155
 156 NTSTATUS ntlmssp_sign_packet(struct ntlmssp_state *ntlmssp_state,
 157                              TALLOC_CTX *sig_mem_ctx,
 158                              const uint8_t *data, size_t length,
 159                              const uint8_t *whole_pdu, size_t pdu_length,
 160                              DATA_BLOB *sig)
 161 {
 162         NTSTATUS nt_status;
 163
 164         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
 165                 DEBUG(3, ("NTLMSSP Signing not negotiated - cannot sign packet!\n"));
 166                 return NT_STATUS_INVALID_PARAMETER;
 167         }
 168
 169         if (!ntlmssp_state->session_key.length) {
 170                 DEBUG(3, ("NO session key, cannot check sign packet\n"));
 171                 return NT_STATUS_NO_USER_SESSION_KEY;
 172         }
 173
 174         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
 175                                                   sig_mem_ctx,
 176                                                   data, length,
 177                                                   whole_pdu, pdu_length,
 178                                                   NTLMSSP_SEND, sig, true);
 179
 180         return nt_status;
 181 }
 182
 183 /**
 184  * Check the signature of an incoming packet
 185  * @note caller *must* check that the signature is the size it expects
 186  *
 187  */
 188
 189 NTSTATUS ntlmssp_check_packet(struct ntlmssp_state *ntlmssp_state,
 190                               const uint8_t *data, size_t length,
 191                               const uint8_t *whole_pdu, size_t pdu_length,
 192                               const DATA_BLOB *sig)
 193 {
 194         DATA_BLOB local_sig;
 195         NTSTATUS nt_status;
 196         TALLOC_CTX *tmp_ctx;
 197
 198         if (!ntlmssp_state->session_key.length) {
 199                 DEBUG(3, ("NO session key, cannot check packet signature\n"));
 200                 return NT_STATUS_NO_USER_SESSION_KEY;
 201         }
 202
 203         if (sig->length < 8) {
 204                 DEBUG(0, ("NTLMSSP packet check failed due to short signature (%lu bytes)!\n",
 205                           (unsigned long)sig->length));
 206         }
 207
 208         tmp_ctx = talloc_new(ntlmssp_state);
 209         if (!tmp_ctx) {
 210                 return NT_STATUS_NO_MEMORY;
 211         }
 212
 213         nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
 214                                                   tmp_ctx,
 215                                                   data, length,
 216                                                   whole_pdu, pdu_length,
 217                                                   NTLMSSP_RECEIVE,
 218                                                   &local_sig, true);
 219
 220         if (!NT_STATUS_IS_OK(nt_status)) {
 221                 DEBUG(0,("NTLMSSP packet sig creation failed with %s\n",
 222                          nt_errstr(nt_status)));
 223                 talloc_free(tmp_ctx);
 224                 return nt_status;
 225         }
 226
 227         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 228                 if (local_sig.length != sig->length ||
 229                     memcmp(local_sig.data, sig->data, sig->length) != 0) {
 230                         DEBUG(5, ("BAD SIG NTLM2: wanted signature of\n"));
 231                         dump_data(5, local_sig.data, local_sig.length);
 232
 233                         DEBUG(5, ("BAD SIG: got signature of\n"));
 234                         dump_data(5, sig->data, sig->length);
 235
 236                         DEBUG(0, ("NTLMSSP NTLM2 packet check failed due to invalid signature!\n"));
 237                         talloc_free(tmp_ctx);
 238                         return NT_STATUS_ACCESS_DENIED;
 239                 }
 240         } else {
 241                 if (local_sig.length != sig->length ||
 242                     memcmp(local_sig.data + 8, sig->data + 8, sig->length - 8) != 0) {
 243                         DEBUG(5, ("BAD SIG NTLM1: wanted signature of\n"));
 244                         dump_data(5, local_sig.data, local_sig.length);
 245
 246                         DEBUG(5, ("BAD SIG: got signature of\n"));
 247                         dump_data(5, sig->data, sig->length);
 248
 249                         DEBUG(0, ("NTLMSSP NTLM1 packet check failed due to invalid signature!\n"));
 250                         talloc_free(tmp_ctx);
 251                         return NT_STATUS_ACCESS_DENIED;
 252                 }
 253         }
 254         dump_data_pw("checked ntlmssp signature\n", sig->data, sig->length);
 255         DEBUG(10,("ntlmssp_check_packet: NTLMSSP signature OK !\n"));
 256
 257         talloc_free(tmp_ctx);
 258         return NT_STATUS_OK;
 259 }
 260
 261 /**
 262  * Seal data with the NTLMSSP algorithm
 263  *
 264  */
 265
 266 NTSTATUS ntlmssp_seal_packet(struct ntlmssp_state *ntlmssp_state,
 267                              TALLOC_CTX *sig_mem_ctx,
 268                              uint8_t *data, size_t length,
 269                              const uint8_t *whole_pdu, size_t pdu_length,
 270                              DATA_BLOB *sig)
 271 {
 272         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL)) {
 273                 DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
 274                 return NT_STATUS_INVALID_PARAMETER;
 275         }
 276
 277         if (!(ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN)) {
 278                 DEBUG(3, ("NTLMSSP Sealing not negotiated - cannot seal packet!\n"));
 279                 return NT_STATUS_INVALID_PARAMETER;
 280         }
 281
 282         if (!ntlmssp_state->session_key.length) {
 283                 DEBUG(3, ("NO session key, cannot seal packet\n"));
 284                 return NT_STATUS_NO_USER_SESSION_KEY;
 285         }
 286
 287         DEBUG(10,("ntlmssp_seal_data: seal\n"));
 288         dump_data_pw("ntlmssp clear data\n", data, length);
 289         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 290                 NTSTATUS nt_status;
 291                 /*
 292                  * The order of these two operations matters - we
 293                  * must first seal the packet, then seal the
 294                  * sequence number - this is because the
 295                  * send_seal_hash is not constant, but is is rather
 296                  * updated with each iteration
 297                  */
 298                 nt_status = ntlmssp_make_packet_signature(ntlmssp_state,
 299                                                           sig_mem_ctx,
 300                                                           data, length,
 301                                                           whole_pdu, pdu_length,
 302                                                           NTLMSSP_SEND,
 303                                                           sig, false);
 304                 if (!NT_STATUS_IS_OK(nt_status)) {
 305                         return nt_status;
 306                 }
 307
 308                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
 309                                    data, length);
 310                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_KEY_EXCH) {
 311                         arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
 312                                            sig->data+4, 8);
 313                 }
 314         } else {
 315                 NTSTATUS status;
 316                 uint32_t crc;
 317
 318                 crc = crc32_calc_buffer(data, length);
 319
 320                 status = msrpc_gen(sig_mem_ctx,
 321                                sig, "dddd",
 322                                NTLMSSP_SIGN_VERSION, 0, crc,
 323                                ntlmssp_state->crypt->ntlm.seq_num);
 324                 if (!NT_STATUS_IS_OK(status)) {
 325                         return status;
 326                 }
 327
 328                 /*
 329                  * The order of these two operations matters - we
 330                  * must first seal the packet, then seal the
 331                  * sequence number - this is because the ntlmv1_arc4_state
 332                  * is not constant, but is is rather updated with
 333                  * each iteration
 334                  */
 335
 336                 dump_arc4_state("ntlmv1 arc4 state:\n",
 337                                 &ntlmssp_state->crypt->ntlm.seal_state);
 338                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
 339                                    data, length);
 340
 341                 dump_arc4_state("ntlmv1 arc4 state:\n",
 342                                 &ntlmssp_state->crypt->ntlm.seal_state);
 343
 344                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
 345                                    sig->data+4, sig->length-4);
 346
 347                 ntlmssp_state->crypt->ntlm.seq_num++;
 348         }
 349         dump_data_pw("ntlmssp signature\n", sig->data, sig->length);
 350         dump_data_pw("ntlmssp sealed data\n", data, length);
 351
 352         return NT_STATUS_OK;
 353 }
 354
 355 /**
 356  * Unseal data with the NTLMSSP algorithm
 357  *
 358  */
 359
 360 NTSTATUS ntlmssp_unseal_packet(struct ntlmssp_state *ntlmssp_state,
 361                                uint8_t *data, size_t length,
 362                                const uint8_t *whole_pdu, size_t pdu_length,
 363                                const DATA_BLOB *sig)
 364 {
 365         NTSTATUS status;
 366         if (!ntlmssp_state->session_key.length) {
 367                 DEBUG(3, ("NO session key, cannot unseal packet\n"));
 368                 return NT_STATUS_NO_USER_SESSION_KEY;
 369         }
 370
 371         DEBUG(10,("ntlmssp_unseal_packet: seal\n"));
 372         dump_data_pw("ntlmssp sealed data\n", data, length);
 373
 374         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 375                 /* First unseal the data. */
 376                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
 377                                    data, length);
 378                 dump_data_pw("ntlmv2 clear data\n", data, length);
 379         } else {
 380                 arcfour_crypt_sbox(&ntlmssp_state->crypt->ntlm.seal_state,
 381                                    data, length);
 382                 dump_data_pw("ntlmv1 clear data\n", data, length);
 383         }
 384         status = ntlmssp_check_packet(ntlmssp_state,
 385                                       data, length,
 386                                       whole_pdu, pdu_length,
 387                                       sig);
 388
 389         if (!NT_STATUS_IS_OK(status)) {
 390                 DEBUG(1,("NTLMSSP packet check for unseal failed due to invalid signature on %llu bytes of input:\n",
 391                          (unsigned long long)length));
 392         }
 393         return status;
 394 }
 395
 396 NTSTATUS ntlmssp_wrap(struct ntlmssp_state *ntlmssp_state,
 397                       TALLOC_CTX *out_mem_ctx,
 398                       const DATA_BLOB *in,
 399                       DATA_BLOB *out)
 400 {
 401         NTSTATUS nt_status;
 402         DATA_BLOB sig;
 403
 404         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
 405                 *out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
 406                 if (!out->data) {
 407                         return NT_STATUS_NO_MEMORY;
 408                 }
 409                 memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
 410
 411                 nt_status = ntlmssp_seal_packet(ntlmssp_state, out_mem_ctx,
 412                                                 out->data + NTLMSSP_SIG_SIZE,
 413                                                 out->length - NTLMSSP_SIG_SIZE,
 414                                                 out->data + NTLMSSP_SIG_SIZE,
 415                                                 out->length - NTLMSSP_SIG_SIZE,
 416                                                 &sig);
 417
 418                 if (NT_STATUS_IS_OK(nt_status)) {
 419                         memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
 420                         talloc_free(sig.data);
 421                 }
 422                 return nt_status;
 423
 424         } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) {
 425
 426                 *out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
 427                 if (!out->data) {
 428                         return NT_STATUS_NO_MEMORY;
 429                 }
 430                 memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
 431
 432                 nt_status = ntlmssp_sign_packet(ntlmssp_state, out_mem_ctx,
 433                                                 out->data + NTLMSSP_SIG_SIZE,
 434                                                 out->length - NTLMSSP_SIG_SIZE,
 435                                                 out->data + NTLMSSP_SIG_SIZE,
 436                                                 out->length - NTLMSSP_SIG_SIZE,
 437                                                 &sig);
 438
 439                 if (NT_STATUS_IS_OK(nt_status)) {
 440                         memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
 441                         talloc_free(sig.data);
 442                 }
 443                 return nt_status;
 444         } else {
 445                 *out = data_blob_talloc(out_mem_ctx, in->data, in->length);
 446                 if (!out->data) {
 447                         return NT_STATUS_NO_MEMORY;
 448                 }
 449                 return NT_STATUS_OK;
 450         }
 451 }
 452
 453 NTSTATUS ntlmssp_unwrap(struct ntlmssp_state *ntlmssp_state,
 454                         TALLOC_CTX *out_mem_ctx,
 455                         const DATA_BLOB *in,
 456                         DATA_BLOB *out)
 457 {
 458         DATA_BLOB sig;
 459
 460         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
 461                 if (in->length < NTLMSSP_SIG_SIZE) {
 462                         return NT_STATUS_INVALID_PARAMETER;
 463                 }
 464                 sig.data = in->data;
 465                 sig.length = NTLMSSP_SIG_SIZE;
 466
 467                 *out = data_blob_talloc(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
 468
 469                 return ntlmssp_unseal_packet(ntlmssp_state,
 470                                              out->data, out->length,
 471                                              out->data, out->length,
 472                                              &sig);
 473
 474         } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) {
 475                 NTSTATUS status;
 476                 struct ntlmssp_crypt_direction save_direction;
 477
 478                 if (in->length < NTLMSSP_SIG_SIZE) {
 479                         return NT_STATUS_INVALID_PARAMETER;
 480                 }
 481                 sig.data = in->data;
 482                 sig.length = NTLMSSP_SIG_SIZE;
 483                 *out = data_blob_talloc(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
 484
 485                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 486                         save_direction = ntlmssp_state->crypt->ntlm2.receiving;
 487                 } else {
 488                         save_direction = ntlmssp_state->crypt->ntlm;
 489                 }
 490
 491                 status = ntlmssp_check_packet(ntlmssp_state,
 492                                               out->data, out->length,
 493                                               out->data, out->length,
 494                                               &sig);
 495                 if (!NT_STATUS_IS_OK(status)) {
 496                         NTSTATUS check_status = status;
 497                         /*
 498                          * The Windows LDAP libraries seems to have a bug
 499                          * and always use sealing even if only signing was
 500                          * negotiated. So we need to fallback.
 501                          */
 502
 503                         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 504                                 ntlmssp_state->crypt->ntlm2.receiving = save_direction;
 505                         } else {
 506                                 ntlmssp_state->crypt->ntlm = save_direction;
 507                         }
 508
 509                         status = ntlmssp_unseal_packet(ntlmssp_state,
 510                                                        out->data,
 511                                                        out->length,
 512                                                        out->data,
 513                                                        out->length,
 514                                                        &sig);
 515                         if (NT_STATUS_IS_OK(status)) {
 516                                 ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
 517                         } else {
 518                                 status = check_status;
 519                         }
 520                 }
 521
 522                 if (!NT_STATUS_IS_OK(status)) {
 523                         DEBUG(1, ("NTLMSSP packet check for unwrap failed due to invalid signature\n"));
 524                 }
 525                 return status;
 526         } else {
 527                 *out = data_blob_talloc(out_mem_ctx, in->data, in->length);
 528                 if (!out->data) {
 529                         return NT_STATUS_NO_MEMORY;
 530                 }
 531                 return NT_STATUS_OK;
 532         }
 533 }
 534
 535 /**
 536    Initialise the state for NTLMSSP signing.
 537 */
 538 NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
 539 {
 540         DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
 541         debug_ntlmssp_flags(ntlmssp_state->neg_flags);
 542
 543         if (ntlmssp_state->session_key.length < 8) {
 544                 DEBUG(3, ("NO session key, cannot intialise signing\n"));
 545                 return NT_STATUS_NO_USER_SESSION_KEY;
 546         }
 547
 548         ntlmssp_state->crypt = talloc_zero(ntlmssp_state,
 549                                            union ntlmssp_crypt_state);
 550         if (ntlmssp_state->crypt == NULL) {
 551                 return NT_STATUS_NO_MEMORY;
 552         }
 553
 554         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 555                 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
 556                 const char *send_sign_const;
 557                 const char *send_seal_const;
 558                 const char *recv_sign_const;
 559                 const char *recv_seal_const;
 560                 uint8_t send_seal_key[16];
 561                 DATA_BLOB send_seal_blob = data_blob_const(send_seal_key,
 562                                            sizeof(send_seal_key));
 563                 uint8_t recv_seal_key[16];
 564                 DATA_BLOB recv_seal_blob = data_blob_const(recv_seal_key,
 565                                            sizeof(recv_seal_key));
 566
 567                 switch (ntlmssp_state->role) {
 568                 case NTLMSSP_CLIENT:
 569                         send_sign_const = CLI_SIGN;
 570                         send_seal_const = CLI_SEAL;
 571                         recv_sign_const = SRV_SIGN;
 572                         recv_seal_const = SRV_SEAL;
 573                         break;
 574                 case NTLMSSP_SERVER:
 575                         send_sign_const = SRV_SIGN;
 576                         send_seal_const = SRV_SEAL;
 577                         recv_sign_const = CLI_SIGN;
 578                         recv_seal_const = CLI_SEAL;
 579                         break;
 580                 default:
 581                         return NT_STATUS_INTERNAL_ERROR;
 582                 }
 583
 584                 /*
 585                  * Weaken NTLMSSP keys to cope with down-level
 586                  * clients, servers and export restrictions.
 587                  *
 588                  * We probably should have some parameters to
 589                  * control this, once we get NTLM2 working.
 590                  *
 591                  * Key weakening was not performed on the master key
 592                  * for NTLM2, but must be done on the encryption subkeys only.
 593                  */
 594
 595                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
 596                         /* nothing to do */
 597                 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
 598                         weak_session_key.length = 7;
 599                 } else { /* forty bits */
 600                         weak_session_key.length = 5;
 601                 }
 602
 603                 dump_data_pw("NTLMSSP weakend master key:\n",
 604                              weak_session_key.data,
 605                              weak_session_key.length);
 606
 607                 /* SEND: sign key */
 608                 calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.sending.sign_key,
 609                                 ntlmssp_state->session_key, send_sign_const);
 610                 dump_data_pw("NTLMSSP send sign key:\n",
 611                              ntlmssp_state->crypt->ntlm2.sending.sign_key, 16);
 612
 613                 /* SEND: seal ARCFOUR pad */
 614                 calc_ntlmv2_key(send_seal_key,
 615                                 weak_session_key, send_seal_const);
 616                 dump_data_pw("NTLMSSP send seal key:\n", send_seal_key, 16);
 617
 618                 arcfour_init(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
 619                              &send_seal_blob);
 620
 621                 dump_arc4_state("NTLMSSP send seal arc4 state:\n",
 622                                 &ntlmssp_state->crypt->ntlm2.sending.seal_state);
 623
 624                 /* SEND: seq num */
 625                 ntlmssp_state->crypt->ntlm2.sending.seq_num = 0;
 626
 627                 /* RECV: sign key */
 628                 calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.receiving.sign_key,
 629                                 ntlmssp_state->session_key, recv_sign_const);
 630                 dump_data_pw("NTLMSSP recv sign key:\n",
 631                              ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16);
 632
 633                 /* RECV: seal ARCFOUR pad */
 634                 calc_ntlmv2_key(recv_seal_key,
 635                                 weak_session_key, recv_seal_const);
 636                 dump_data_pw("NTLMSSP recv seal key:\n", recv_seal_key, 16);
 637
 638                 arcfour_init(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
 639                              &recv_seal_blob);
 640
 641                 dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
 642                                 &ntlmssp_state->crypt->ntlm2.receiving.seal_state);
 643
 644                 /* RECV: seq num */
 645                 ntlmssp_state->crypt->ntlm2.receiving.seq_num = 0;
 646         } else {
 647                 uint8_t weak_session_key[8];
 648                 DATA_BLOB seal_session_key = ntlmssp_state->session_key;
 649                 bool do_weak = false;
 650
 651                 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
 652
 653                 /*
 654                  * Key weakening not performed on the master key for NTLM2
 655                  * and does not occour for NTLM1. Therefore we only need
 656                  * to do this for the LM_KEY.
 657                  */
 658                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
 659                         do_weak = true;
 660                 }
 661
 662                 /*
 663                  * Nothing to weaken.
 664                  * We certainly don't want to 'extend' the length...
 665                  */
 666                 if (seal_session_key.length < 16) {
 667                         /* TODO: is this really correct? */
 668                         do_weak = false;
 669                 }
 670
 671                 if (do_weak) {
 672                         memcpy(weak_session_key, seal_session_key.data, 8);
 673                         seal_session_key = data_blob_const(weak_session_key, 8);
 674
 675                         /*
 676                          * LM key doesn't support 128 bit crypto, so this is
 677                          * the best we can do. If you negotiate 128 bit, but
 678                          * not 56, you end up with 40 bit...
 679                          */
 680                         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
 681                                 weak_session_key[7] = 0xa0;
 682                         } else { /* forty bits */
 683                                 weak_session_key[5] = 0xe5;
 684                                 weak_session_key[6] = 0x38;
 685                                 weak_session_key[7] = 0xb0;
 686                         }
 687                 }
 688
 689                 arcfour_init(&ntlmssp_state->crypt->ntlm.seal_state,
 690                              &seal_session_key);
 691
 692                 dump_arc4_state("NTLMv1 arc4 state:\n",
 693                                 &ntlmssp_state->crypt->ntlm.seal_state);
 694
 695                 ntlmssp_state->crypt->ntlm.seq_num = 0;
 696         }
 697
 698         return NT_STATUS_OK;
 699 }