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         MD5_CTX 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                 if (in->length + NTLMSSP_SIG_SIZE < in->length) {
 406                         return NT_STATUS_INVALID_PARAMETER;
 407                 }
 408
 409                 *out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
 410                 if (!out->data) {
 411                         return NT_STATUS_NO_MEMORY;
 412                 }
 413                 memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
 414
 415                 nt_status = ntlmssp_seal_packet(ntlmssp_state, out_mem_ctx,
 416                                                 out->data + NTLMSSP_SIG_SIZE,
 417                                                 out->length - NTLMSSP_SIG_SIZE,
 418                                                 out->data + NTLMSSP_SIG_SIZE,
 419                                                 out->length - NTLMSSP_SIG_SIZE,
 420                                                 &sig);
 421
 422                 if (NT_STATUS_IS_OK(nt_status)) {
 423                         memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
 424                         talloc_free(sig.data);
 425                 }
 426                 return nt_status;
 427
 428         } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) {
 429                 if (in->length + NTLMSSP_SIG_SIZE < in->length) {
 430                         return NT_STATUS_INVALID_PARAMETER;
 431                 }
 432
 433                 *out = data_blob_talloc(out_mem_ctx, NULL, in->length + NTLMSSP_SIG_SIZE);
 434                 if (!out->data) {
 435                         return NT_STATUS_NO_MEMORY;
 436                 }
 437                 memcpy(out->data + NTLMSSP_SIG_SIZE, in->data, in->length);
 438
 439                 nt_status = ntlmssp_sign_packet(ntlmssp_state, out_mem_ctx,
 440                                                 out->data + NTLMSSP_SIG_SIZE,
 441                                                 out->length - NTLMSSP_SIG_SIZE,
 442                                                 out->data + NTLMSSP_SIG_SIZE,
 443                                                 out->length - NTLMSSP_SIG_SIZE,
 444                                                 &sig);
 445
 446                 if (NT_STATUS_IS_OK(nt_status)) {
 447                         memcpy(out->data, sig.data, NTLMSSP_SIG_SIZE);
 448                         talloc_free(sig.data);
 449                 }
 450                 return nt_status;
 451         } else {
 452                 *out = data_blob_talloc(out_mem_ctx, in->data, in->length);
 453                 if (!out->data) {
 454                         return NT_STATUS_NO_MEMORY;
 455                 }
 456                 return NT_STATUS_OK;
 457         }
 458 }
 459
 460 NTSTATUS ntlmssp_unwrap(struct ntlmssp_state *ntlmssp_state,
 461                         TALLOC_CTX *out_mem_ctx,
 462                         const DATA_BLOB *in,
 463                         DATA_BLOB *out)
 464 {
 465         DATA_BLOB sig;
 466
 467         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SEAL) {
 468                 if (in->length < NTLMSSP_SIG_SIZE) {
 469                         return NT_STATUS_INVALID_PARAMETER;
 470                 }
 471                 sig.data = in->data;
 472                 sig.length = NTLMSSP_SIG_SIZE;
 473
 474                 *out = data_blob_talloc(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
 475
 476                 return ntlmssp_unseal_packet(ntlmssp_state,
 477                                              out->data, out->length,
 478                                              out->data, out->length,
 479                                              &sig);
 480
 481         } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN) {
 482                 NTSTATUS status;
 483                 struct ntlmssp_crypt_direction save_direction;
 484
 485                 if (in->length < NTLMSSP_SIG_SIZE) {
 486                         return NT_STATUS_INVALID_PARAMETER;
 487                 }
 488                 sig.data = in->data;
 489                 sig.length = NTLMSSP_SIG_SIZE;
 490                 *out = data_blob_talloc(out_mem_ctx, in->data + NTLMSSP_SIG_SIZE, in->length - NTLMSSP_SIG_SIZE);
 491
 492                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 493                         save_direction = ntlmssp_state->crypt->ntlm2.receiving;
 494                 } else {
 495                         save_direction = ntlmssp_state->crypt->ntlm;
 496                 }
 497
 498                 status = ntlmssp_check_packet(ntlmssp_state,
 499                                               out->data, out->length,
 500                                               out->data, out->length,
 501                                               &sig);
 502                 if (!NT_STATUS_IS_OK(status)) {
 503                         NTSTATUS check_status = status;
 504                         /*
 505                          * The Windows LDAP libraries seems to have a bug
 506                          * and always use sealing even if only signing was
 507                          * negotiated. So we need to fallback.
 508                          */
 509
 510                         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 511                                 ntlmssp_state->crypt->ntlm2.receiving = save_direction;
 512                         } else {
 513                                 ntlmssp_state->crypt->ntlm = save_direction;
 514                         }
 515
 516                         status = ntlmssp_unseal_packet(ntlmssp_state,
 517                                                        out->data,
 518                                                        out->length,
 519                                                        out->data,
 520                                                        out->length,
 521                                                        &sig);
 522                         if (NT_STATUS_IS_OK(status)) {
 523                                 ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
 524                         } else {
 525                                 status = check_status;
 526                         }
 527                 }
 528
 529                 if (!NT_STATUS_IS_OK(status)) {
 530                         DEBUG(1, ("NTLMSSP packet check for unwrap failed due to invalid signature\n"));
 531                 }
 532                 return status;
 533         } else {
 534                 *out = data_blob_talloc(out_mem_ctx, in->data, in->length);
 535                 if (!out->data) {
 536                         return NT_STATUS_NO_MEMORY;
 537                 }
 538                 return NT_STATUS_OK;
 539         }
 540 }
 541
 542 /**
 543    Initialise the state for NTLMSSP signing.
 544 */
 545 NTSTATUS ntlmssp_sign_init(struct ntlmssp_state *ntlmssp_state)
 546 {
 547         DEBUG(3, ("NTLMSSP Sign/Seal - Initialising with flags:\n"));
 548         debug_ntlmssp_flags(ntlmssp_state->neg_flags);
 549
 550         if (ntlmssp_state->session_key.length < 8) {
 551                 DEBUG(3, ("NO session key, cannot intialise signing\n"));
 552                 return NT_STATUS_NO_USER_SESSION_KEY;
 553         }
 554
 555         ntlmssp_state->crypt = talloc_zero(ntlmssp_state,
 556                                            union ntlmssp_crypt_state);
 557         if (ntlmssp_state->crypt == NULL) {
 558                 return NT_STATUS_NO_MEMORY;
 559         }
 560
 561         if (ntlmssp_state->force_wrap_seal &&
 562             (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_SIGN))
 563         {
 564                 /*
 565                  * We need to handle NTLMSSP_NEGOTIATE_SIGN as
 566                  * NTLMSSP_NEGOTIATE_SEAL if GENSEC_FEATURE_LDAP_STYLE
 567                  * is requested.
 568                  *
 569                  * The negotiation of flags (and authentication)
 570                  * is completed when ntlmssp_sign_init() is called
 571                  * so we can safely pretent NTLMSSP_NEGOTIATE_SEAL
 572                  * was negotiated.
 573                  */
 574                 ntlmssp_state->neg_flags |= NTLMSSP_NEGOTIATE_SEAL;
 575         }
 576
 577         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_NTLM2) {
 578                 DATA_BLOB weak_session_key = ntlmssp_state->session_key;
 579                 const char *send_sign_const;
 580                 const char *send_seal_const;
 581                 const char *recv_sign_const;
 582                 const char *recv_seal_const;
 583                 uint8_t send_seal_key[16];
 584                 DATA_BLOB send_seal_blob = data_blob_const(send_seal_key,
 585                                            sizeof(send_seal_key));
 586                 uint8_t recv_seal_key[16];
 587                 DATA_BLOB recv_seal_blob = data_blob_const(recv_seal_key,
 588                                            sizeof(recv_seal_key));
 589
 590                 switch (ntlmssp_state->role) {
 591                 case NTLMSSP_CLIENT:
 592                         send_sign_const = CLI_SIGN;
 593                         send_seal_const = CLI_SEAL;
 594                         recv_sign_const = SRV_SIGN;
 595                         recv_seal_const = SRV_SEAL;
 596                         break;
 597                 case NTLMSSP_SERVER:
 598                         send_sign_const = SRV_SIGN;
 599                         send_seal_const = SRV_SEAL;
 600                         recv_sign_const = CLI_SIGN;
 601                         recv_seal_const = CLI_SEAL;
 602                         break;
 603                 default:
 604                         return NT_STATUS_INTERNAL_ERROR;
 605                 }
 606
 607                 /*
 608                  * Weaken NTLMSSP keys to cope with down-level
 609                  * clients, servers and export restrictions.
 610                  *
 611                  * We probably should have some parameters to
 612                  * control this, once we get NTLM2 working.
 613                  *
 614                  * Key weakening was not performed on the master key
 615                  * for NTLM2, but must be done on the encryption subkeys only.
 616                  */
 617
 618                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_128) {
 619                         /* nothing to do */
 620                 } else if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
 621                         weak_session_key.length = 7;
 622                 } else { /* forty bits */
 623                         weak_session_key.length = 5;
 624                 }
 625
 626                 dump_data_pw("NTLMSSP weakend master key:\n",
 627                              weak_session_key.data,
 628                              weak_session_key.length);
 629
 630                 /* SEND: sign key */
 631                 calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.sending.sign_key,
 632                                 ntlmssp_state->session_key, send_sign_const);
 633                 dump_data_pw("NTLMSSP send sign key:\n",
 634                              ntlmssp_state->crypt->ntlm2.sending.sign_key, 16);
 635
 636                 /* SEND: seal ARCFOUR pad */
 637                 calc_ntlmv2_key(send_seal_key,
 638                                 weak_session_key, send_seal_const);
 639                 dump_data_pw("NTLMSSP send seal key:\n", send_seal_key, 16);
 640
 641                 arcfour_init(&ntlmssp_state->crypt->ntlm2.sending.seal_state,
 642                              &send_seal_blob);
 643
 644                 dump_arc4_state("NTLMSSP send seal arc4 state:\n",
 645                                 &ntlmssp_state->crypt->ntlm2.sending.seal_state);
 646
 647                 /* SEND: seq num */
 648                 ntlmssp_state->crypt->ntlm2.sending.seq_num = 0;
 649
 650                 /* RECV: sign key */
 651                 calc_ntlmv2_key(ntlmssp_state->crypt->ntlm2.receiving.sign_key,
 652                                 ntlmssp_state->session_key, recv_sign_const);
 653                 dump_data_pw("NTLMSSP recv sign key:\n",
 654                              ntlmssp_state->crypt->ntlm2.receiving.sign_key, 16);
 655
 656                 /* RECV: seal ARCFOUR pad */
 657                 calc_ntlmv2_key(recv_seal_key,
 658                                 weak_session_key, recv_seal_const);
 659                 dump_data_pw("NTLMSSP recv seal key:\n", recv_seal_key, 16);
 660
 661                 arcfour_init(&ntlmssp_state->crypt->ntlm2.receiving.seal_state,
 662                              &recv_seal_blob);
 663
 664                 dump_arc4_state("NTLMSSP recv seal arc4 state:\n",
 665                                 &ntlmssp_state->crypt->ntlm2.receiving.seal_state);
 666
 667                 /* RECV: seq num */
 668                 ntlmssp_state->crypt->ntlm2.receiving.seq_num = 0;
 669         } else {
 670                 uint8_t weak_session_key[8];
 671                 DATA_BLOB seal_session_key = ntlmssp_state->session_key;
 672                 bool do_weak = false;
 673
 674                 DEBUG(5, ("NTLMSSP Sign/Seal - using NTLM1\n"));
 675
 676                 /*
 677                  * Key weakening not performed on the master key for NTLM2
 678                  * and does not occour for NTLM1. Therefore we only need
 679                  * to do this for the LM_KEY.
 680                  */
 681                 if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_LM_KEY) {
 682                         do_weak = true;
 683                 }
 684
 685                 /*
 686                  * Nothing to weaken.
 687                  * We certainly don't want to 'extend' the length...
 688                  */
 689                 if (seal_session_key.length < 16) {
 690                         /* TODO: is this really correct? */
 691                         do_weak = false;
 692                 }
 693
 694                 if (do_weak) {
 695                         memcpy(weak_session_key, seal_session_key.data, 8);
 696                         seal_session_key = data_blob_const(weak_session_key, 8);
 697
 698                         /*
 699                          * LM key doesn't support 128 bit crypto, so this is
 700                          * the best we can do. If you negotiate 128 bit, but
 701                          * not 56, you end up with 40 bit...
 702                          */
 703                         if (ntlmssp_state->neg_flags & NTLMSSP_NEGOTIATE_56) {
 704                                 weak_session_key[7] = 0xa0;
 705                         } else { /* forty bits */
 706                                 weak_session_key[5] = 0xe5;
 707                                 weak_session_key[6] = 0x38;
 708                                 weak_session_key[7] = 0xb0;
 709                         }
 710                 }
 711
 712                 arcfour_init(&ntlmssp_state->crypt->ntlm.seal_state,
 713                              &seal_session_key);
 714
 715                 dump_arc4_state("NTLMv1 arc4 state:\n",
 716                                 &ntlmssp_state->crypt->ntlm.seal_state);
 717
 718                 ntlmssp_state->crypt->ntlm.seq_num = 0;
 719         }
 720
 721         return NT_STATUS_OK;
 722 }