source/libsmb/smb_signing.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    SMB Signing Code
   4    Copyright (C) Jeremy Allison 2003.
   5    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2002-2003
   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 2 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, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 /* Lookup a packet's MID (multiplex id) and figure out it's sequence number */
  25 struct outstanding_packet_lookup {
  26         uint16 mid;
  27         uint32 reply_seq_num;
  28         struct outstanding_packet_lookup *prev, *next;
  29 };
  30
  31 /* Store the data for an ongoing trans/trans2/nttrans operation. */
  32 struct trans_info_context {
  33         uint16 mid;
  34         uint32 send_seq_num;
  35         uint32 reply_seq_num;
  36 };
  37
  38 struct smb_basic_signing_context {
  39         DATA_BLOB mac_key;
  40         uint32 send_seq_num;
  41         struct trans_info_context *trans_info;
  42         struct outstanding_packet_lookup *outstanding_packet_list;
  43 };
  44
  45 static void store_sequence_for_reply(struct outstanding_packet_lookup **list,
  46                                      uint16 mid, uint32 reply_seq_num)
  47 {
  48         struct outstanding_packet_lookup *t;
  49         struct outstanding_packet_lookup *tmp;
  50
  51         t = smb_xmalloc(sizeof(*t));
  52         ZERO_STRUCTP(t);
  53
  54         DLIST_ADD_END(*list, t, tmp);
  55         t->mid = mid;
  56         t->reply_seq_num = reply_seq_num;
  57         DEBUG(10,("store_sequence_for_reply: stored seq = %u mid = %u\n",
  58                         (unsigned int)reply_seq_num, (unsigned int)mid ));
  59 }
  60
  61 static BOOL get_sequence_for_reply(struct outstanding_packet_lookup **list,
  62                                    uint16 mid, uint32 *reply_seq_num)
  63 {
  64         struct outstanding_packet_lookup *t;
  65
  66         for (t = *list; t; t = t->next) {
  67                 if (t->mid == mid) {
  68                         *reply_seq_num = t->reply_seq_num;
  69                         DEBUG(10,("get_sequence_for_reply: found seq = %u mid = %u\n",
  70                                 (unsigned int)t->reply_seq_num, (unsigned int)t->mid ));
  71                         DLIST_REMOVE(*list, t);
  72                         SAFE_FREE(t);
  73                         return True;
  74                 }
  75         }
  76         return False;
  77 }
  78
  79 /***********************************************************
  80  SMB signing - Common code before we set a new signing implementation
  81 ************************************************************/
  82
  83 static BOOL cli_set_smb_signing_common(struct cli_state *cli)
  84 {
  85         if (!cli->sign_info.negotiated_smb_signing
  86             && !cli->sign_info.mandatory_signing) {
  87                 return False;
  88         }
  89
  90         if (cli->sign_info.doing_signing) {
  91                 return False;
  92         }
  93
  94         if (cli->sign_info.free_signing_context)
  95                 cli->sign_info.free_signing_context(&cli->sign_info);
  96
  97         /* These calls are INCOMPATIBLE with SMB signing */
  98         cli->readbraw_supported = False;
  99         cli->writebraw_supported = False;
 100
 101         return True;
 102 }
 103
 104 /***********************************************************
 105  SMB signing - Common code for 'real' implementations
 106 ************************************************************/
 107
 108 static BOOL set_smb_signing_real_common(struct smb_sign_info *si)
 109 {
 110         if (si->mandatory_signing) {
 111                 DEBUG(5, ("Mandatory SMB signing enabled!\n"));
 112         }
 113
 114         si->doing_signing = True;
 115         DEBUG(5, ("SMB signing enabled!\n"));
 116
 117         return True;
 118 }
 119
 120 static void mark_packet_signed(char *outbuf)
 121 {
 122         uint16 flags2;
 123         flags2 = SVAL(outbuf,smb_flg2);
 124         flags2 |= FLAGS2_SMB_SECURITY_SIGNATURES;
 125         SSVAL(outbuf,smb_flg2, flags2);
 126 }
 127
 128 /***********************************************************
 129  SMB signing - NULL implementation - calculate a MAC to send.
 130 ************************************************************/
 131
 132 static void null_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 133 {
 134         /* we can't zero out the sig, as we might be trying to send a
 135            session request - which is NBT-level, not SMB level and doesn't
 136            have the field */
 137         return;
 138 }
 139
 140 /***********************************************************
 141  SMB signing - NULL implementation - check a MAC sent by server.
 142 ************************************************************/
 143
 144 static BOOL null_check_incoming_message(char *inbuf, struct smb_sign_info *si)
 145 {
 146         return True;
 147 }
 148
 149 /***********************************************************
 150  SMB signing - NULL implementation - free signing context
 151 ************************************************************/
 152
 153 static void null_free_signing_context(struct smb_sign_info *si)
 154 {
 155         return;
 156 }
 157
 158 /**
 159  SMB signing - NULL implementation - setup the MAC key.
 160
 161  @note Used as an initialisation only - it will not correctly
 162        shut down a real signing mechanism
 163 */
 164
 165 static BOOL null_set_signing(struct smb_sign_info *si)
 166 {
 167         si->signing_context = NULL;
 168
 169         si->sign_outgoing_message = null_sign_outgoing_message;
 170         si->check_incoming_message = null_check_incoming_message;
 171         si->free_signing_context = null_free_signing_context;
 172
 173         return True;
 174 }
 175
 176 /**
 177  * Free the signing context
 178  */
 179
 180 static void free_signing_context(struct smb_sign_info *si)
 181 {
 182         if (si->free_signing_context) {
 183                 si->free_signing_context(si);
 184                 si->signing_context = NULL;
 185         }
 186
 187         null_set_signing(si);
 188 }
 189
 190
 191 static BOOL signing_good(char *inbuf, struct smb_sign_info *si, BOOL good)
 192 {
 193         if (good && !si->doing_signing) {
 194                 si->doing_signing = True;
 195         }
 196
 197         if (!good) {
 198                 if (si->doing_signing) {
 199                         struct smb_basic_signing_context *data = si->signing_context;
 200
 201                         /* W2K sends a bad first signature but the sign engine is on.... JRA. */
 202                         if (data->send_seq_num > 1)
 203                                 DEBUG(1, ("signing_good: SMB signature check failed!\n"));
 204
 205                         return False;
 206                 } else {
 207                         DEBUG(3, ("signing_good: Peer did not sign reply correctly\n"));
 208                         free_signing_context(si);
 209                         return False;
 210                 }
 211         }
 212         return True;
 213 }
 214
 215 /***********************************************************
 216  SMB signing - Simple implementation - calculate a MAC on the packet
 217 ************************************************************/
 218
 219 static void simple_packet_signature(struct smb_basic_signing_context *data,
 220                                     const uchar *buf, uint32 seq_number,
 221                                     unsigned char calc_md5_mac[16])
 222 {
 223         const size_t offset_end_of_sig = (smb_ss_field + 8);
 224         unsigned char sequence_buf[8];
 225         struct MD5Context md5_ctx;
 226
 227         /*
 228          * Firstly put the sequence number into the first 4 bytes.
 229          * and zero out the next 4 bytes.
 230          *
 231          * We do this here, to avoid modifying the packet.
 232          */
 233
 234         DEBUG(10,("simple_packet_signature: sequence number %u\n", seq_number ));
 235
 236         SIVAL(sequence_buf, 0, seq_number);
 237         SIVAL(sequence_buf, 4, 0);
 238
 239         /* Calculate the 16 byte MAC - but don't alter the data in the
 240            incoming packet.
 241
 242            This makes for a bit of fussing about, but it's not too bad.
 243         */
 244         MD5Init(&md5_ctx);
 245
 246         /* intialise with the key */
 247         MD5Update(&md5_ctx, data->mac_key.data,
 248                   data->mac_key.length);
 249
 250         /* copy in the first bit of the SMB header */
 251         MD5Update(&md5_ctx, buf + 4, smb_ss_field - 4);
 252
 253         /* copy in the sequence number, instead of the signature */
 254         MD5Update(&md5_ctx, sequence_buf, sizeof(sequence_buf));
 255
 256         /* copy in the rest of the packet in, skipping the signature */
 257         MD5Update(&md5_ctx, buf + offset_end_of_sig,
 258                   smb_len(buf) - (offset_end_of_sig - 4));
 259
 260         /* calculate the MD5 sig */
 261         MD5Final(calc_md5_mac, &md5_ctx);
 262 }
 263
 264
 265 /***********************************************************
 266  SMB signing - Client implementation - send the MAC.
 267 ************************************************************/
 268
 269 static void client_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 270 {
 271         unsigned char calc_md5_mac[16];
 272         struct smb_basic_signing_context *data = si->signing_context;
 273         uint32 send_seq_num;
 274
 275         if (!si->doing_signing)
 276                 return;
 277
 278         /* JRA Paranioa test - we should be able to get rid of this... */
 279         if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) {
 280                 DEBUG(1, ("client_sign_outgoing_message: Logic error. Can't check signature on short packet! smb_len = %u\n",
 281                                         smb_len(outbuf) ));
 282                 abort();
 283         }
 284
 285         /* mark the packet as signed - BEFORE we sign it...*/
 286         mark_packet_signed(outbuf);
 287
 288         if (data->trans_info)
 289                 send_seq_num = data->trans_info->send_seq_num;
 290         else
 291                 send_seq_num = data->send_seq_num;
 292
 293         simple_packet_signature(data, outbuf, send_seq_num, calc_md5_mac);
 294
 295         DEBUG(10, ("client_sign_outgoing_message: sent SMB signature of\n"));
 296         dump_data(10, calc_md5_mac, 8);
 297
 298         memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8);
 299
 300 /*      cli->outbuf[smb_ss_field+2]=0;
 301         Uncomment this to test if the remote server actually verifies signatures...*/
 302
 303         if (data->trans_info)
 304                 return;
 305
 306         data->send_seq_num++;
 307         store_sequence_for_reply(&data->outstanding_packet_list,
 308                                  SVAL(outbuf,smb_mid),
 309                                  data->send_seq_num);
 310         data->send_seq_num++;
 311 }
 312
 313 /***********************************************************
 314  SMB signing - Client implementation - check a MAC sent by server.
 315 ************************************************************/
 316
 317 static BOOL client_check_incoming_message(char *inbuf, struct smb_sign_info *si)
 318 {
 319         BOOL good;
 320         uint32 reply_seq_number;
 321         unsigned char calc_md5_mac[16];
 322         unsigned char *server_sent_mac;
 323
 324         struct smb_basic_signing_context *data = si->signing_context;
 325
 326         if (!si->doing_signing)
 327                 return True;
 328
 329         if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
 330                 DEBUG(1, ("client_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
 331                 return False;
 332         }
 333
 334         if (data->trans_info) {
 335                 reply_seq_number = data->trans_info->reply_seq_num;
 336         } else if (!get_sequence_for_reply(&data->outstanding_packet_list,
 337                                     SVAL(inbuf, smb_mid),
 338                                     &reply_seq_number)) {
 339                 DEBUG(1, ("client_check_incoming_message: failed to get sequence number %u for reply.\n",
 340                                         (unsigned int) SVAL(inbuf, smb_mid) ));
 341                 return False;
 342         }
 343
 344         simple_packet_signature(data, inbuf, reply_seq_number, calc_md5_mac);
 345
 346         server_sent_mac = &inbuf[smb_ss_field];
 347         good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
 348
 349         if (!good) {
 350                 DEBUG(5, ("client_check_incoming_message: BAD SIG: wanted SMB signature of\n"));
 351                 dump_data(5, calc_md5_mac, 8);
 352
 353                 DEBUG(5, ("client_check_incoming_message: BAD SIG: got SMB signature of\n"));
 354                 dump_data(5, server_sent_mac, 8);
 355 #if 1 /* JRATEST */
 356                 {
 357                         int i;
 358                         reply_seq_number -= 5;
 359                         for (i = 0; i < 10; i++, reply_seq_number++) {
 360                                 simple_packet_signature(data, inbuf, reply_seq_number, calc_md5_mac);
 361                                 if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
 362                                         DEBUG(0,("client_check_incoming_message: out of seq. seq num %u matches.\n",
 363                                                         reply_seq_number ));
 364                                         break;
 365                                 }
 366                         }
 367                 }
 368 #endif /* JRATEST */
 369
 370         } else {
 371                 DEBUG(10, ("client_check_incoming_message:: seq %u: got good SMB signature of\n", (unsigned int)reply_seq_number));
 372                 dump_data(10, server_sent_mac, 8);
 373         }
 374         return signing_good(inbuf, si, good);
 375 }
 376
 377 /***********************************************************
 378  SMB signing - Simple implementation - free signing context
 379 ************************************************************/
 380
 381 static void simple_free_signing_context(struct smb_sign_info *si)
 382 {
 383         struct smb_basic_signing_context *data = si->signing_context;
 384         struct outstanding_packet_lookup *list = data->outstanding_packet_list;
 385
 386         while (list) {
 387                 struct outstanding_packet_lookup *old_head = list;
 388                 DLIST_REMOVE(list, list);
 389                 SAFE_FREE(old_head);
 390         }
 391
 392         data_blob_free(&data->mac_key);
 393
 394         if (data->trans_info)
 395                 SAFE_FREE(data->trans_info);
 396
 397         SAFE_FREE(si->signing_context);
 398
 399         return;
 400 }
 401
 402 /***********************************************************
 403  SMB signing - Simple implementation - setup the MAC key.
 404 ************************************************************/
 405
 406 BOOL cli_simple_set_signing(struct cli_state *cli, const uchar user_session_key[16], const DATA_BLOB response)
 407 {
 408         struct smb_basic_signing_context *data;
 409
 410         if (!user_session_key)
 411                 return False;
 412
 413         if (!cli_set_smb_signing_common(cli)) {
 414                 return False;
 415         }
 416
 417         if (!set_smb_signing_real_common(&cli->sign_info)) {
 418                 return False;
 419         }
 420
 421         data = smb_xmalloc(sizeof(*data));
 422         memset(data, '\0', sizeof(*data));
 423
 424         cli->sign_info.signing_context = data;
 425
 426         data->mac_key = data_blob(NULL, response.length + 16);
 427
 428         memcpy(&data->mac_key.data[0], user_session_key, 16);
 429
 430         DEBUG(10, ("cli_simple_set_signing: user_session_key\n"));
 431         dump_data(10, user_session_key, 16);
 432
 433         if (response.length) {
 434                 memcpy(&data->mac_key.data[16],response.data, response.length);
 435                 DEBUG(10, ("cli_simple_set_signing: response_data\n"));
 436                 dump_data(10, response.data, response.length);
 437         } else {
 438                 DEBUG(10, ("cli_simple_set_signing: NULL response_data\n"));
 439         }
 440
 441         /* Initialise the sequence number */
 442         data->send_seq_num = 0;
 443
 444         /* Initialise the list of outstanding packets */
 445         data->outstanding_packet_list = NULL;
 446
 447         cli->sign_info.sign_outgoing_message = client_sign_outgoing_message;
 448         cli->sign_info.check_incoming_message = client_check_incoming_message;
 449         cli->sign_info.free_signing_context = simple_free_signing_context;
 450
 451         return True;
 452 }
 453
 454 /***********************************************************
 455  Tell client code we are in a multiple trans reply state.
 456 ************************************************************/
 457
 458 void cli_signing_trans_start(struct cli_state *cli)
 459 {
 460         struct smb_basic_signing_context *data = cli->sign_info.signing_context;
 461
 462         if (!cli->sign_info.doing_signing || !data)
 463                 return;
 464
 465         data->trans_info = smb_xmalloc(sizeof(struct trans_info_context));
 466         ZERO_STRUCTP(data->trans_info);
 467
 468         data->trans_info->send_seq_num = data->send_seq_num;
 469         data->trans_info->mid = SVAL(cli->outbuf,smb_mid);
 470         data->trans_info->reply_seq_num = data->send_seq_num+1;
 471
 472         DEBUG(10,("cli_signing_trans_start: storing mid = %u, reply_seq_num = %u, send_seq_num = %u \
 473 data->send_seq_num = %u\n",
 474                         (unsigned int)data->trans_info->mid,
 475                         (unsigned int)data->trans_info->reply_seq_num,
 476                         (unsigned int)data->trans_info->send_seq_num,
 477                         (unsigned int)data->send_seq_num ));
 478 }
 479
 480 /***********************************************************
 481  Tell client code we are out of a multiple trans reply state.
 482 ************************************************************/
 483
 484 void cli_signing_trans_stop(struct cli_state *cli)
 485 {
 486         struct smb_basic_signing_context *data = cli->sign_info.signing_context;
 487
 488         if (!cli->sign_info.doing_signing || !data)
 489                 return;
 490
 491         SAFE_FREE(data->trans_info);
 492         data->trans_info = NULL;
 493
 494         data->send_seq_num += 2;
 495 }
 496
 497 /***********************************************************
 498  SMB signing - TEMP implementation - calculate a MAC to send.
 499 ************************************************************/
 500
 501 static void temp_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 502 {
 503         /* mark the packet as signed - BEFORE we sign it...*/
 504         mark_packet_signed(outbuf);
 505
 506         /* I wonder what BSRSPYL stands for - but this is what MS
 507            actually sends! */
 508         memcpy(&outbuf[smb_ss_field], "BSRSPYL ", 8);
 509         return;
 510 }
 511
 512 /***********************************************************
 513  SMB signing - TEMP implementation - check a MAC sent by server.
 514 ************************************************************/
 515
 516 static BOOL temp_check_incoming_message(char *inbuf, struct smb_sign_info *si)
 517 {
 518         return True;
 519 }
 520
 521 /***********************************************************
 522  SMB signing - TEMP implementation - free signing context
 523 ************************************************************/
 524
 525 static void temp_free_signing_context(struct smb_sign_info *si)
 526 {
 527         return;
 528 }
 529
 530 /***********************************************************
 531  SMB signing - NULL implementation - setup the MAC key.
 532 ************************************************************/
 533
 534 BOOL cli_null_set_signing(struct cli_state *cli)
 535 {
 536         return null_set_signing(&cli->sign_info);
 537 }
 538
 539 /***********************************************************
 540  SMB signing - temp implementation - setup the MAC key.
 541 ************************************************************/
 542
 543 BOOL cli_temp_set_signing(struct cli_state *cli)
 544 {
 545         if (!cli_set_smb_signing_common(cli)) {
 546                 return False;
 547         }
 548
 549         cli->sign_info.signing_context = NULL;
 550
 551         cli->sign_info.sign_outgoing_message = temp_sign_outgoing_message;
 552         cli->sign_info.check_incoming_message = temp_check_incoming_message;
 553         cli->sign_info.free_signing_context = temp_free_signing_context;
 554
 555         return True;
 556 }
 557
 558 void cli_free_signing_context(struct cli_state *cli)
 559 {
 560         free_signing_context(&cli->sign_info);
 561 }
 562
 563 /**
 564  * Sign a packet with the current mechanism
 565  */
 566
 567 void cli_calculate_sign_mac(struct cli_state *cli)
 568 {
 569         cli->sign_info.sign_outgoing_message(cli->outbuf, &cli->sign_info);
 570 }
 571
 572 /**
 573  * Check a packet with the current mechanism
 574  * @return False if we had an established signing connection
 575  *         which had a bad checksum, True otherwise.
 576  */
 577
 578 BOOL cli_check_sign_mac(struct cli_state *cli)
 579 {
 580         if (!cli->sign_info.check_incoming_message(cli->inbuf, &cli->sign_info)) {
 581                 free_signing_context(&cli->sign_info);
 582                 return False;
 583         }
 584         return True;
 585 }
 586
 587 static BOOL packet_is_oplock_break(char *buf)
 588 {
 589         if (CVAL(buf,smb_com) != SMBlockingX)
 590                 return False;
 591
 592         if (CVAL(buf,smb_vwv3) != LOCKING_ANDX_OPLOCK_RELEASE)
 593                 return False;
 594
 595         return True;
 596 }
 597
 598 /***********************************************************
 599  SMB signing - Server implementation - send the MAC.
 600 ************************************************************/
 601
 602 static void srv_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 603 {
 604         unsigned char calc_md5_mac[16];
 605         struct smb_basic_signing_context *data = si->signing_context;
 606         uint32 send_seq_number = data->send_seq_num;
 607         BOOL was_deferred_packet = False;
 608         uint16 mid;
 609
 610         if (!si->doing_signing) {
 611                 if (si->allow_smb_signing && si->negotiated_smb_signing) {
 612                         mid = SVAL(outbuf, smb_mid);
 613
 614                         was_deferred_packet = get_sequence_for_reply(&data->outstanding_packet_list,
 615                                                     mid, &send_seq_number);
 616                         if (!was_deferred_packet) {
 617                                 /*
 618                                  * Is this an outgoing oplock break ? If so, store the
 619                                  * mid in the outstanding list.
 620                                  */
 621
 622                                 if (packet_is_oplock_break(outbuf)) {
 623                                         store_sequence_for_reply(&data->outstanding_packet_list,
 624                                                                  mid, data->send_seq_num);
 625                                 }
 626
 627                                 data->send_seq_num++;
 628                         }
 629                 }
 630                 return;
 631         }
 632
 633         /* JRA Paranioa test - we should be able to get rid of this... */
 634         if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) {
 635                 DEBUG(1, ("srv_sign_outgoing_message: Logic error. Can't send signature on short packet! smb_len = %u\n",
 636                                         smb_len(outbuf) ));
 637                 abort();
 638         }
 639
 640         /* mark the packet as signed - BEFORE we sign it...*/
 641         mark_packet_signed(outbuf);
 642
 643         mid = SVAL(outbuf, smb_mid);
 644
 645         /* See if this is a reply for a deferred packet. */
 646         was_deferred_packet = get_sequence_for_reply(&data->outstanding_packet_list, mid, &send_seq_number);
 647
 648         if (data->trans_info && (data->trans_info->mid == mid)) {
 649                 /* This is a reply in a trans stream. Use the sequence
 650                  * number associated with the stream mid. */
 651                 send_seq_number = data->trans_info->send_seq_num;
 652         }
 653
 654         simple_packet_signature(data, outbuf, send_seq_number, calc_md5_mac);
 655
 656         DEBUG(10, ("srv_sign_outgoing_message: seq %u: sent SMB signature of\n", (unsigned int)send_seq_number));
 657         dump_data(10, calc_md5_mac, 8);
 658
 659         memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8);
 660
 661 /*      cli->outbuf[smb_ss_field+2]=0;
 662         Uncomment this to test if the remote server actually verifies signatures...*/
 663
 664         if (!was_deferred_packet) {
 665                 if (!data->trans_info) {
 666                         /* Always increment if not in a trans stream. */
 667                         data->send_seq_num++;
 668                 } else if ((data->trans_info->send_seq_num == data->send_seq_num) || (data->trans_info->mid != mid)) {
 669                         /* Increment if this is the first reply in a trans stream or a
 670                          * packet that doesn't belong to this stream (different mid). */
 671                         data->send_seq_num++;
 672                 }
 673         }
 674 }
 675
 676 /***********************************************************
 677  SMB signing - Server implementation - check a MAC sent by server.
 678 ************************************************************/
 679
 680 static BOOL srv_check_incoming_message(char *inbuf, struct smb_sign_info *si)
 681 {
 682         BOOL good;
 683         struct smb_basic_signing_context *data = si->signing_context;
 684         uint32 reply_seq_number = data->send_seq_num;
 685         unsigned char calc_md5_mac[16];
 686         unsigned char *server_sent_mac;
 687         uint mid;
 688
 689         if (!si->doing_signing)
 690                 return True;
 691
 692         if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
 693                 DEBUG(1, ("srv_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
 694                 return False;
 695         }
 696
 697         mid = SVAL(inbuf, smb_mid);
 698
 699         /* Is this part of a trans stream ? */
 700         if (data->trans_info && (data->trans_info->mid == mid)) {
 701                 /* If so we don't increment the sequence. */
 702                 reply_seq_number = data->trans_info->reply_seq_num;
 703         } else {
 704                 /* We always increment the sequence number. */
 705                 data->send_seq_num++;
 706                 /* Oplock break requests store an outgoing mid in the packet list. */
 707                 if (packet_is_oplock_break(inbuf))
 708                         get_sequence_for_reply(&data->outstanding_packet_list, mid, &reply_seq_number);
 709         }
 710
 711         simple_packet_signature(data, inbuf, reply_seq_number, calc_md5_mac);
 712
 713         server_sent_mac = &inbuf[smb_ss_field];
 714         good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
 715
 716         if (!good) {
 717
 718                 DEBUG(5, ("srv_check_incoming_message: BAD SIG: wanted SMB signature of\n"));
 719                 dump_data(5, calc_md5_mac, 8);
 720
 721                 DEBUG(5, ("srv_check_incoming_message: BAD SIG: got SMB signature of\n"));
 722                 dump_data(5, server_sent_mac, 8);
 723
 724 #if 1 /* JRATEST */
 725                 {
 726                         int i;
 727                         reply_seq_number -= 5;
 728                         for (i = 0; i < 10; i++, reply_seq_number++) {
 729                                 simple_packet_signature(data, inbuf, reply_seq_number, calc_md5_mac);
 730                                 if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
 731                                         DEBUG(0,("srv_check_incoming_message: out of seq. seq num %u matches.\n",
 732                                                         reply_seq_number ));
 733                                         break;
 734                                 }
 735                         }
 736                 }
 737 #endif /* JRATEST */
 738
 739         } else {
 740                 DEBUG(10, ("srv_check_incoming_message: seq %u: got good SMB signature of\n", (unsigned int)reply_seq_number));
 741                 dump_data(10, server_sent_mac, 8);
 742         }
 743         return signing_good(inbuf, si, good);
 744 }
 745
 746 /***********************************************************
 747  SMB signing - server API's.
 748 ************************************************************/
 749
 750 static struct smb_sign_info srv_sign_info = {
 751         null_sign_outgoing_message,
 752         null_check_incoming_message,
 753         null_free_signing_context,
 754         NULL,
 755         False,
 756         False,
 757         False,
 758         False
 759 };
 760
 761 /***********************************************************
 762  Turn signing off or on for oplock break code.
 763 ************************************************************/
 764
 765 BOOL srv_oplock_set_signing(BOOL onoff)
 766 {
 767         BOOL ret = srv_sign_info.doing_signing;
 768         srv_sign_info.doing_signing = onoff;
 769         return ret;
 770 }
 771
 772 /***********************************************************
 773  Called to validate an incoming packet from the client.
 774 ************************************************************/
 775
 776 BOOL srv_check_sign_mac(char *inbuf)
 777 {
 778         /* Check if it's a session keepalive. */
 779         if(CVAL(inbuf,0) == SMBkeepalive)
 780                 return True;
 781
 782         return srv_sign_info.check_incoming_message(inbuf, &srv_sign_info);
 783 }
 784
 785 /***********************************************************
 786  Called to sign an outgoing packet to the client.
 787 ************************************************************/
 788
 789 void srv_calculate_sign_mac(char *outbuf)
 790 {
 791         /* Check if it's a session keepalive. */
 792         /* JRA Paranioa test - do we ever generate these in the server ? */
 793         if(CVAL(outbuf,0) == SMBkeepalive)
 794                 return;
 795
 796         srv_sign_info.sign_outgoing_message(outbuf, &srv_sign_info);
 797 }
 798
 799 /***********************************************************
 800  Called by server to defer an outgoing packet.
 801 ************************************************************/
 802
 803 void srv_defer_sign_response(uint16 mid)
 804 {
 805         struct smb_basic_signing_context *data;
 806
 807         if (!srv_sign_info.doing_signing)
 808                 return;
 809
 810         data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
 811
 812         if (!data)
 813                 return;
 814
 815         store_sequence_for_reply(&data->outstanding_packet_list,
 816                                  mid, data->send_seq_num);
 817         data->send_seq_num++;
 818 }
 819
 820 /***********************************************************
 821  Called to remove sequence records when a deferred packet is
 822  cancelled by mid. This should never find one....
 823 ************************************************************/
 824
 825 void srv_cancel_sign_response(uint16 mid)
 826 {
 827         struct smb_basic_signing_context *data;
 828         uint32 dummy_seq;
 829
 830         if (!srv_sign_info.doing_signing)
 831                 return;
 832
 833         data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
 834
 835         if (!data)
 836                 return;
 837
 838         DEBUG(10,("srv_cancel_sign_response: for mid %u\n", (unsigned int)mid ));
 839
 840         while (get_sequence_for_reply(&data->outstanding_packet_list, mid, &dummy_seq))
 841                 ;
 842 }
 843
 844 /***********************************************************
 845  Called by server negprot when signing has been negotiated.
 846 ************************************************************/
 847
 848 void srv_set_signing_negotiated(void)
 849 {
 850         srv_sign_info.allow_smb_signing = True;
 851         srv_sign_info.negotiated_smb_signing = True;
 852         if (lp_server_signing() == Required)
 853                 srv_sign_info.mandatory_signing = True;
 854
 855         srv_sign_info.sign_outgoing_message = temp_sign_outgoing_message;
 856         srv_sign_info.check_incoming_message = temp_check_incoming_message;
 857         srv_sign_info.free_signing_context = temp_free_signing_context;
 858 }
 859
 860 /***********************************************************
 861  Returns whether signing is active. We can't use sendfile or raw
 862  reads/writes if it is.
 863 ************************************************************/
 864
 865 BOOL srv_is_signing_active(void)
 866 {
 867         return srv_sign_info.doing_signing;
 868 }
 869
 870 /***********************************************************
 871  Tell server code we are in a multiple trans reply state.
 872 ************************************************************/
 873
 874 void srv_signing_trans_start(uint16 mid)
 875 {
 876         struct smb_basic_signing_context *data;
 877
 878         if (!srv_sign_info.doing_signing)
 879                 return;
 880
 881         data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
 882         if (!data)
 883                 return;
 884
 885         data->trans_info = smb_xmalloc(sizeof(struct trans_info_context));
 886         ZERO_STRUCTP(data->trans_info);
 887
 888         data->trans_info->reply_seq_num = data->send_seq_num-1;
 889         data->trans_info->mid = mid;
 890         data->trans_info->send_seq_num = data->send_seq_num;
 891
 892         DEBUG(10,("srv_signing_trans_start: storing mid = %u, reply_seq_num = %u, send_seq_num = %u \
 893 data->send_seq_num = %u\n",
 894                         (unsigned int)mid,
 895                         (unsigned int)data->trans_info->reply_seq_num,
 896                         (unsigned int)data->trans_info->send_seq_num,
 897                         (unsigned int)data->send_seq_num ));
 898 }
 899
 900 /***********************************************************
 901  Tell server code we are out of a multiple trans reply state.
 902 ************************************************************/
 903
 904 void srv_signing_trans_stop(void)
 905 {
 906         struct smb_basic_signing_context *data;
 907
 908         if (!srv_sign_info.doing_signing)
 909                 return;
 910
 911         data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
 912         if (!data || !data->trans_info)
 913                 return;
 914
 915         DEBUG(10,("srv_signing_trans_stop: removing mid = %u, reply_seq_num = %u, send_seq_num = %u \
 916 data->send_seq_num = %u\n",
 917                         (unsigned int)data->trans_info->mid,
 918                         (unsigned int)data->trans_info->reply_seq_num,
 919                         (unsigned int)data->trans_info->send_seq_num,
 920                         (unsigned int)data->send_seq_num ));
 921
 922         SAFE_FREE(data->trans_info);
 923         data->trans_info = NULL;
 924 }
 925
 926 /***********************************************************
 927  Turn on signing from this packet onwards.
 928 ************************************************************/
 929
 930 void srv_set_signing(const uchar user_session_key[16], const DATA_BLOB response)
 931 {
 932         struct smb_basic_signing_context *data;
 933
 934         if (!user_session_key)
 935                 return;
 936
 937         if (!srv_sign_info.negotiated_smb_signing && !srv_sign_info.mandatory_signing) {
 938                 DEBUG(5,("srv_set_signing: signing negotiated = %u, mandatory_signing = %u. Not allowing smb signing.\n",
 939                         (unsigned int)srv_sign_info.negotiated_smb_signing,
 940                         (unsigned int)srv_sign_info.mandatory_signing ));
 941                 return;
 942         }
 943
 944         /* Once we've turned on, ignore any more sessionsetups. */
 945         if (srv_sign_info.doing_signing) {
 946                 return;
 947         }
 948
 949         if (srv_sign_info.free_signing_context)
 950                 srv_sign_info.free_signing_context(&srv_sign_info);
 951
 952         srv_sign_info.doing_signing = True;
 953
 954         data = smb_xmalloc(sizeof(*data));
 955         memset(data, '\0', sizeof(*data));
 956
 957         srv_sign_info.signing_context = data;
 958
 959         data->mac_key = data_blob(NULL, response.length + 16);
 960
 961         memcpy(&data->mac_key.data[0], user_session_key, 16);
 962         if (response.length)
 963                 memcpy(&data->mac_key.data[16],response.data, response.length);
 964
 965         /* Initialise the sequence number */
 966         data->send_seq_num = 0;
 967
 968         /* Initialise the list of outstanding packets */
 969         data->outstanding_packet_list = NULL;
 970
 971         srv_sign_info.sign_outgoing_message = srv_sign_outgoing_message;
 972         srv_sign_info.check_incoming_message = srv_check_incoming_message;
 973         srv_sign_info.free_signing_context = simple_free_signing_context;
 974 }