release/src/router/samba3/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         struct outstanding_packet_lookup *prev, *next;
  27         uint16 mid;
  28         uint32 reply_seq_num;
  29         BOOL can_delete; /* Set to False in trans state. */
  30 };
  31
  32 struct smb_basic_signing_context {
  33         DATA_BLOB mac_key;
  34         uint32 send_seq_num;
  35         struct outstanding_packet_lookup *outstanding_packet_list;
  36 };
  37
  38 static BOOL store_sequence_for_reply(struct outstanding_packet_lookup **list,
  39                                      uint16 mid, uint32 reply_seq_num)
  40 {
  41         struct outstanding_packet_lookup *t;
  42
  43         /* Ensure we only add a mid once. */
  44         for (t = *list; t; t = t->next) {
  45                 if (t->mid == mid) {
  46                         return False;
  47                 }
  48         }
  49
  50         t = SMB_XMALLOC_P(struct outstanding_packet_lookup);
  51         ZERO_STRUCTP(t);
  52
  53         t->mid = mid;
  54         t->reply_seq_num = reply_seq_num;
  55         t->can_delete = True;
  56
  57         /*
  58          * Add to the *start* of the list not the end of the list.
  59          * This ensures that the *last* send sequence with this mid
  60          * is returned by preference.
  61          * This can happen if the mid wraps and one of the early
  62          * mid numbers didn't get a reply and is still lurking on
  63          * the list. JRA. Found by Fran Fabrizio <fran@cis.uab.edu>.
  64          */
  65
  66         DLIST_ADD(*list, t);
  67         DEBUG(10,("store_sequence_for_reply: stored seq = %u mid = %u\n",
  68                         (unsigned int)reply_seq_num, (unsigned int)mid ));
  69         return True;
  70 }
  71
  72 static BOOL get_sequence_for_reply(struct outstanding_packet_lookup **list,
  73                                    uint16 mid, uint32 *reply_seq_num)
  74 {
  75         struct outstanding_packet_lookup *t;
  76
  77         for (t = *list; t; t = t->next) {
  78                 if (t->mid == mid) {
  79                         *reply_seq_num = t->reply_seq_num;
  80                         DEBUG(10,("get_sequence_for_reply: found seq = %u mid = %u\n",
  81                                 (unsigned int)t->reply_seq_num, (unsigned int)t->mid ));
  82                         if (t->can_delete) {
  83                                 DLIST_REMOVE(*list, t);
  84                                 SAFE_FREE(t);
  85                         }
  86                         return True;
  87                 }
  88         }
  89         return False;
  90 }
  91
  92 static BOOL set_sequence_can_delete_flag(struct outstanding_packet_lookup **list, uint16 mid, BOOL can_delete_entry)
  93 {
  94         struct outstanding_packet_lookup *t;
  95
  96         for (t = *list; t; t = t->next) {
  97                 if (t->mid == mid) {
  98                         t->can_delete = can_delete_entry;
  99                         return True;
 100                 }
 101         }
 102         return False;
 103 }
 104
 105 /***********************************************************
 106  SMB signing - Common code before we set a new signing implementation
 107 ************************************************************/
 108
 109 static BOOL cli_set_smb_signing_common(struct cli_state *cli)
 110 {
 111         if (!cli->sign_info.allow_smb_signing) {
 112                 return False;
 113         }
 114
 115         if (!cli->sign_info.negotiated_smb_signing
 116             && !cli->sign_info.mandatory_signing) {
 117                 return False;
 118         }
 119
 120         if (cli->sign_info.doing_signing) {
 121                 return False;
 122         }
 123
 124         if (cli->sign_info.free_signing_context)
 125                 cli->sign_info.free_signing_context(&cli->sign_info);
 126
 127         /* These calls are INCOMPATIBLE with SMB signing */
 128         cli->readbraw_supported = False;
 129         cli->writebraw_supported = False;
 130
 131         return True;
 132 }
 133
 134 /***********************************************************
 135  SMB signing - Common code for 'real' implementations
 136 ************************************************************/
 137
 138 static BOOL set_smb_signing_real_common(struct smb_sign_info *si)
 139 {
 140         if (si->mandatory_signing) {
 141                 DEBUG(5, ("Mandatory SMB signing enabled!\n"));
 142         }
 143
 144         si->doing_signing = True;
 145         DEBUG(5, ("SMB signing enabled!\n"));
 146
 147         return True;
 148 }
 149
 150 static void mark_packet_signed(char *outbuf)
 151 {
 152         uint16 flags2;
 153         flags2 = SVAL(outbuf,smb_flg2);
 154         flags2 |= FLAGS2_SMB_SECURITY_SIGNATURES;
 155         SSVAL(outbuf,smb_flg2, flags2);
 156 }
 157
 158 /***********************************************************
 159  SMB signing - NULL implementation - calculate a MAC to send.
 160 ************************************************************/
 161
 162 static void null_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 163 {
 164         /* we can't zero out the sig, as we might be trying to send a
 165            session request - which is NBT-level, not SMB level and doesn't
 166            have the field */
 167         return;
 168 }
 169
 170 /***********************************************************
 171  SMB signing - NULL implementation - check a MAC sent by server.
 172 ************************************************************/
 173
 174 static BOOL null_check_incoming_message(char *inbuf, struct smb_sign_info *si, BOOL must_be_ok)
 175 {
 176         return True;
 177 }
 178
 179 /***********************************************************
 180  SMB signing - NULL implementation - free signing context
 181 ************************************************************/
 182
 183 static void null_free_signing_context(struct smb_sign_info *si)
 184 {
 185         return;
 186 }
 187
 188 /**
 189  SMB signing - NULL implementation - setup the MAC key.
 190
 191  @note Used as an initialisation only - it will not correctly
 192        shut down a real signing mechanism
 193 */
 194
 195 static BOOL null_set_signing(struct smb_sign_info *si)
 196 {
 197         si->signing_context = NULL;
 198
 199         si->sign_outgoing_message = null_sign_outgoing_message;
 200         si->check_incoming_message = null_check_incoming_message;
 201         si->free_signing_context = null_free_signing_context;
 202
 203         return True;
 204 }
 205
 206 /**
 207  * Free the signing context
 208  */
 209
 210 static void free_signing_context(struct smb_sign_info *si)
 211 {
 212         if (si->free_signing_context) {
 213                 si->free_signing_context(si);
 214                 si->signing_context = NULL;
 215         }
 216
 217         null_set_signing(si);
 218 }
 219
 220
 221 static BOOL signing_good(char *inbuf, struct smb_sign_info *si, BOOL good, uint32 seq, BOOL must_be_ok)
 222 {
 223         if (good) {
 224
 225                 if (!si->doing_signing) {
 226                         si->doing_signing = True;
 227                 }
 228
 229                 if (!si->seen_valid) {
 230                         si->seen_valid = True;
 231                 }
 232
 233         } else {
 234                 if (!si->mandatory_signing && !si->seen_valid) {
 235
 236                         if (!must_be_ok) {
 237                                 return True;
 238                         }
 239                         /* Non-mandatory signing - just turn off if this is the first bad packet.. */
 240                         DEBUG(5, ("srv_check_incoming_message: signing negotiated but not required and peer\n"
 241                                   "isn't sending correct signatures. Turning off.\n"));
 242                         si->negotiated_smb_signing = False;
 243                         si->allow_smb_signing = False;
 244                         si->doing_signing = False;
 245                         free_signing_context(si);
 246                         return True;
 247                 } else if (!must_be_ok) {
 248                         /* This packet is known to be unsigned */
 249                         return True;
 250                 } else {
 251                         /* Mandatory signing or bad packet after signing started - fail and disconnect. */
 252                         if (seq)
 253                                 DEBUG(0, ("signing_good: BAD SIG: seq %u\n", (unsigned int)seq));
 254                         return False;
 255                 }
 256         }
 257         return True;
 258 }
 259
 260 /***********************************************************
 261  SMB signing - Simple implementation - calculate a MAC on the packet
 262 ************************************************************/
 263
 264 static void simple_packet_signature(struct smb_basic_signing_context *data,
 265                                     const uchar *buf, uint32 seq_number,
 266                                     unsigned char calc_md5_mac[16])
 267 {
 268         const size_t offset_end_of_sig = (smb_ss_field + 8);
 269         unsigned char sequence_buf[8];
 270         struct MD5Context md5_ctx;
 271 #if 0
 272         /* JRA - apparently this is incorrect. */
 273         unsigned char key_buf[16];
 274 #endif
 275
 276         /*
 277          * Firstly put the sequence number into the first 4 bytes.
 278          * and zero out the next 4 bytes.
 279          *
 280          * We do this here, to avoid modifying the packet.
 281          */
 282
 283         DEBUG(10,("simple_packet_signature: sequence number %u\n", seq_number ));
 284
 285         SIVAL(sequence_buf, 0, seq_number);
 286         SIVAL(sequence_buf, 4, 0);
 287
 288         /* Calculate the 16 byte MAC - but don't alter the data in the
 289            incoming packet.
 290
 291            This makes for a bit of fussing about, but it's not too bad.
 292         */
 293         MD5Init(&md5_ctx);
 294
 295         /* intialise with the key */
 296         MD5Update(&md5_ctx, data->mac_key.data, data->mac_key.length);
 297 #if 0
 298         /* JRA - apparently this is incorrect. */
 299         /* NB. When making and verifying SMB signatures, Windows apparently
 300                 zero-pads the key to 128 bits if it isn't long enough.
 301                 From Nalin Dahyabhai <nalin@redhat.com> */
 302         if (data->mac_key.length < sizeof(key_buf)) {
 303                 memset(key_buf, 0, sizeof(key_buf));
 304                 MD5Update(&md5_ctx, key_buf, sizeof(key_buf) - data->mac_key.length);
 305         }
 306 #endif
 307
 308         /* copy in the first bit of the SMB header */
 309         MD5Update(&md5_ctx, buf + 4, smb_ss_field - 4);
 310
 311         /* copy in the sequence number, instead of the signature */
 312         MD5Update(&md5_ctx, sequence_buf, sizeof(sequence_buf));
 313
 314         /* copy in the rest of the packet in, skipping the signature */
 315         MD5Update(&md5_ctx, buf + offset_end_of_sig,
 316                   smb_len(buf) - (offset_end_of_sig - 4));
 317
 318         /* calculate the MD5 sig */
 319         MD5Final(calc_md5_mac, &md5_ctx);
 320 }
 321
 322
 323 /***********************************************************
 324  SMB signing - Client implementation - send the MAC.
 325 ************************************************************/
 326
 327 static void client_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 328 {
 329         unsigned char calc_md5_mac[16];
 330         struct smb_basic_signing_context *data = si->signing_context;
 331
 332         if (!si->doing_signing)
 333                 return;
 334
 335         /* JRA Paranioa test - we should be able to get rid of this... */
 336         if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) {
 337                 DEBUG(1, ("client_sign_outgoing_message: Logic error. Can't check signature on short packet! smb_len = %u\n",
 338                                         smb_len(outbuf) ));
 339                 abort();
 340         }
 341
 342         /* mark the packet as signed - BEFORE we sign it...*/
 343         mark_packet_signed(outbuf);
 344
 345         simple_packet_signature(data, (const unsigned char *)outbuf,
 346                                 data->send_seq_num, calc_md5_mac);
 347
 348         DEBUG(10, ("client_sign_outgoing_message: sent SMB signature of\n"));
 349         dump_data(10, (const char *)calc_md5_mac, 8);
 350
 351         memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8);
 352
 353 /*      cli->outbuf[smb_ss_field+2]=0;
 354         Uncomment this to test if the remote server actually verifies signatures...*/
 355
 356         /* Instead of re-introducing the trans_info_conect we
 357            used to have here, we use the fact that during a
 358            SMBtrans/SMBtrans2/SMBnttrans send that the mid stays
 359            constant. This means that calling store_sequence_for_reply()
 360            will return False for all trans secondaries, as the mid is already
 361            on the stored sequence list. As the send_seqence_number must
 362            remain constant for all primary+secondary trans sends, we
 363            only increment the send sequence number when we successfully
 364            add a new entry to the outstanding sequence list. This means
 365            I can isolate the fix here rather than re-adding the trans
 366            signing on/off calls in libsmb/clitrans2.c JRA.
 367          */
 368
 369         if (store_sequence_for_reply(&data->outstanding_packet_list, SVAL(outbuf,smb_mid), data->send_seq_num + 1)) {
 370                 data->send_seq_num += 2;
 371         }
 372 }
 373
 374 /***********************************************************
 375  SMB signing - Client implementation - check a MAC sent by server.
 376 ************************************************************/
 377
 378 static BOOL client_check_incoming_message(char *inbuf, struct smb_sign_info *si, BOOL must_be_ok)
 379 {
 380         BOOL good;
 381         uint32 reply_seq_number;
 382         unsigned char calc_md5_mac[16];
 383         unsigned char *server_sent_mac;
 384
 385         struct smb_basic_signing_context *data = si->signing_context;
 386
 387         if (!si->doing_signing)
 388                 return True;
 389
 390         if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
 391                 DEBUG(1, ("client_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
 392                 return False;
 393         }
 394
 395         if (!get_sequence_for_reply(&data->outstanding_packet_list, SVAL(inbuf, smb_mid), &reply_seq_number)) {
 396                 DEBUG(1, ("client_check_incoming_message: received message "
 397                         "with mid %u with no matching send record.\n", (unsigned int)SVAL(inbuf, smb_mid) ));
 398                 return False;
 399         }
 400
 401         simple_packet_signature(data, (const unsigned char *)inbuf,
 402                                 reply_seq_number, calc_md5_mac);
 403
 404         server_sent_mac = (unsigned char *)&inbuf[smb_ss_field];
 405         good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
 406
 407         if (!good) {
 408                 DEBUG(5, ("client_check_incoming_message: BAD SIG: wanted SMB signature of\n"));
 409                 dump_data(5, (const char *)calc_md5_mac, 8);
 410
 411                 DEBUG(5, ("client_check_incoming_message: BAD SIG: got SMB signature of\n"));
 412                 dump_data(5, (const char *)server_sent_mac, 8);
 413 #if 1 /* JRATEST */
 414                 {
 415                         int i;
 416                         for (i = -5; i < 5; i++) {
 417                                 simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number+i, calc_md5_mac);
 418                                 if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
 419                                         DEBUG(0,("client_check_incoming_message: out of seq. seq num %u matches. \
 420 We were expecting seq %u\n", reply_seq_number+i, reply_seq_number ));
 421                                         break;
 422                                 }
 423                         }
 424                 }
 425 #endif /* JRATEST */
 426
 427         } else {
 428                 DEBUG(10, ("client_check_incoming_message: seq %u: got good SMB signature of\n", (unsigned int)reply_seq_number));
 429                 dump_data(10, (const char *)server_sent_mac, 8);
 430         }
 431         return signing_good(inbuf, si, good, reply_seq_number, must_be_ok);
 432 }
 433
 434 /***********************************************************
 435  SMB signing - Simple implementation - free signing context
 436 ************************************************************/
 437
 438 static void simple_free_signing_context(struct smb_sign_info *si)
 439 {
 440         struct smb_basic_signing_context *data = si->signing_context;
 441         struct outstanding_packet_lookup *list;
 442         struct outstanding_packet_lookup *next;
 443
 444         for (list = data->outstanding_packet_list; list; list = next) {
 445                 next = list->next;
 446                 DLIST_REMOVE(data->outstanding_packet_list, list);
 447                 SAFE_FREE(list);
 448         }
 449
 450         data_blob_free(&data->mac_key);
 451
 452         SAFE_FREE(si->signing_context);
 453
 454         return;
 455 }
 456
 457 /***********************************************************
 458  SMB signing - Simple implementation - setup the MAC key.
 459 ************************************************************/
 460
 461 BOOL cli_simple_set_signing(struct cli_state *cli,
 462                             const DATA_BLOB user_session_key,
 463                             const DATA_BLOB response)
 464 {
 465         struct smb_basic_signing_context *data;
 466
 467         if (!user_session_key.length)
 468                 return False;
 469
 470         if (!cli_set_smb_signing_common(cli)) {
 471                 return False;
 472         }
 473
 474         if (!set_smb_signing_real_common(&cli->sign_info)) {
 475                 return False;
 476         }
 477
 478         data = SMB_XMALLOC_P(struct smb_basic_signing_context);
 479         memset(data, '\0', sizeof(*data));
 480
 481         cli->sign_info.signing_context = data;
 482
 483         data->mac_key = data_blob(NULL, response.length + user_session_key.length);
 484
 485         memcpy(&data->mac_key.data[0], user_session_key.data, user_session_key.length);
 486
 487         DEBUG(10, ("cli_simple_set_signing: user_session_key\n"));
 488         dump_data(10, (const char *)user_session_key.data, user_session_key.length);
 489
 490         if (response.length) {
 491                 memcpy(&data->mac_key.data[user_session_key.length],response.data, response.length);
 492                 DEBUG(10, ("cli_simple_set_signing: response_data\n"));
 493                 dump_data(10, (const char *)response.data, response.length);
 494         } else {
 495                 DEBUG(10, ("cli_simple_set_signing: NULL response_data\n"));
 496         }
 497
 498         dump_data_pw("MAC ssession key is:\n", data->mac_key.data, data->mac_key.length);
 499
 500         /* Initialise the sequence number */
 501         data->send_seq_num = 0;
 502
 503         /* Initialise the list of outstanding packets */
 504         data->outstanding_packet_list = NULL;
 505
 506         cli->sign_info.sign_outgoing_message = client_sign_outgoing_message;
 507         cli->sign_info.check_incoming_message = client_check_incoming_message;
 508         cli->sign_info.free_signing_context = simple_free_signing_context;
 509
 510         return True;
 511 }
 512
 513 /***********************************************************
 514  SMB signing - TEMP implementation - calculate a MAC to send.
 515 ************************************************************/
 516
 517 static void temp_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 518 {
 519         /* mark the packet as signed - BEFORE we sign it...*/
 520         mark_packet_signed(outbuf);
 521
 522         /* I wonder what BSRSPYL stands for - but this is what MS
 523            actually sends! */
 524         memcpy(&outbuf[smb_ss_field], "BSRSPYL ", 8);
 525         return;
 526 }
 527
 528 /***********************************************************
 529  SMB signing - TEMP implementation - check a MAC sent by server.
 530 ************************************************************/
 531
 532 static BOOL temp_check_incoming_message(char *inbuf, struct smb_sign_info *si, BOOL foo)
 533 {
 534         return True;
 535 }
 536
 537 /***********************************************************
 538  SMB signing - TEMP implementation - free signing context
 539 ************************************************************/
 540
 541 static void temp_free_signing_context(struct smb_sign_info *si)
 542 {
 543         return;
 544 }
 545
 546 /***********************************************************
 547  SMB signing - NULL implementation - setup the MAC key.
 548 ************************************************************/
 549
 550 BOOL cli_null_set_signing(struct cli_state *cli)
 551 {
 552         return null_set_signing(&cli->sign_info);
 553 }
 554
 555 /***********************************************************
 556  SMB signing - temp implementation - setup the MAC key.
 557 ************************************************************/
 558
 559 BOOL cli_temp_set_signing(struct cli_state *cli)
 560 {
 561         if (!cli_set_smb_signing_common(cli)) {
 562                 return False;
 563         }
 564
 565         cli->sign_info.signing_context = NULL;
 566
 567         cli->sign_info.sign_outgoing_message = temp_sign_outgoing_message;
 568         cli->sign_info.check_incoming_message = temp_check_incoming_message;
 569         cli->sign_info.free_signing_context = temp_free_signing_context;
 570
 571         return True;
 572 }
 573
 574 void cli_free_signing_context(struct cli_state *cli)
 575 {
 576         free_signing_context(&cli->sign_info);
 577 }
 578
 579 /**
 580  * Sign a packet with the current mechanism
 581  */
 582
 583 void cli_calculate_sign_mac(struct cli_state *cli)
 584 {
 585         cli->sign_info.sign_outgoing_message(cli->outbuf, &cli->sign_info);
 586 }
 587
 588 /**
 589  * Check a packet with the current mechanism
 590  * @return False if we had an established signing connection
 591  *         which had a bad checksum, True otherwise.
 592  */
 593
 594 BOOL cli_check_sign_mac(struct cli_state *cli)
 595 {
 596         if (!cli->sign_info.check_incoming_message(cli->inbuf, &cli->sign_info, True)) {
 597                 free_signing_context(&cli->sign_info);
 598                 return False;
 599         }
 600         return True;
 601 }
 602
 603 /***********************************************************
 604  Enter trans/trans2/nttrans state.
 605 ************************************************************/
 606
 607 BOOL client_set_trans_sign_state_on(struct cli_state *cli, uint16 mid)
 608 {
 609         struct smb_sign_info *si = &cli->sign_info;
 610         struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context;
 611
 612         if (!si->doing_signing) {
 613                 return True;
 614         }
 615
 616         if (!data) {
 617                 return False;
 618         }
 619
 620         if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, False)) {
 621                 return False;
 622         }
 623
 624         return True;
 625 }
 626
 627 /***********************************************************
 628  Leave trans/trans2/nttrans state.
 629 ************************************************************/
 630
 631 BOOL client_set_trans_sign_state_off(struct cli_state *cli, uint16 mid)
 632 {
 633         uint32 reply_seq_num;
 634         struct smb_sign_info *si = &cli->sign_info;
 635         struct smb_basic_signing_context *data = (struct smb_basic_signing_context *)si->signing_context;
 636
 637         if (!si->doing_signing) {
 638                 return True;
 639         }
 640
 641         if (!data) {
 642                 return False;
 643         }
 644
 645         if (!set_sequence_can_delete_flag(&data->outstanding_packet_list, mid, True)) {
 646                 return False;
 647         }
 648
 649         /* Now delete the stored mid entry. */
 650         if (!get_sequence_for_reply(&data->outstanding_packet_list, mid, &reply_seq_num)) {
 651                 return False;
 652         }
 653
 654         return True;
 655 }
 656
 657 /***********************************************************
 658  SMB signing - Server implementation - send the MAC.
 659 ************************************************************/
 660
 661 static void srv_sign_outgoing_message(char *outbuf, struct smb_sign_info *si)
 662 {
 663         unsigned char calc_md5_mac[16];
 664         struct smb_basic_signing_context *data = si->signing_context;
 665         uint32 send_seq_number = data->send_seq_num-1;
 666         uint16 mid;
 667
 668         if (!si->doing_signing) {
 669                 return;
 670         }
 671
 672         /* JRA Paranioa test - we should be able to get rid of this... */
 673         if (smb_len(outbuf) < (smb_ss_field + 8 - 4)) {
 674                 DEBUG(1, ("srv_sign_outgoing_message: Logic error. Can't send signature on short packet! smb_len = %u\n",
 675                                         smb_len(outbuf) ));
 676                 abort();
 677         }
 678
 679         /* mark the packet as signed - BEFORE we sign it...*/
 680         mark_packet_signed(outbuf);
 681
 682         mid = SVAL(outbuf, smb_mid);
 683
 684         /* See if this is a reply for a deferred packet. */
 685         get_sequence_for_reply(&data->outstanding_packet_list, mid, &send_seq_number);
 686
 687         simple_packet_signature(data, (const unsigned char *)outbuf, send_seq_number, calc_md5_mac);
 688
 689         DEBUG(10, ("srv_sign_outgoing_message: seq %u: sent SMB signature of\n", (unsigned int)send_seq_number));
 690         dump_data(10, (const char *)calc_md5_mac, 8);
 691
 692         memcpy(&outbuf[smb_ss_field], calc_md5_mac, 8);
 693
 694 /*      cli->outbuf[smb_ss_field+2]=0;
 695         Uncomment this to test if the remote client actually verifies signatures...*/
 696 }
 697
 698 /***********************************************************
 699  SMB signing - Server implementation - check a MAC sent by server.
 700 ************************************************************/
 701
 702 static BOOL srv_check_incoming_message(char *inbuf, struct smb_sign_info *si, BOOL must_be_ok)
 703 {
 704         BOOL good;
 705         struct smb_basic_signing_context *data = si->signing_context;
 706         uint32 reply_seq_number = data->send_seq_num;
 707         uint32 saved_seq;
 708         unsigned char calc_md5_mac[16];
 709         unsigned char *server_sent_mac;
 710
 711         if (!si->doing_signing)
 712                 return True;
 713
 714         if (smb_len(inbuf) < (smb_ss_field + 8 - 4)) {
 715                 DEBUG(1, ("srv_check_incoming_message: Can't check signature on short packet! smb_len = %u\n", smb_len(inbuf)));
 716                 return False;
 717         }
 718
 719         /* We always increment the sequence number. */
 720         data->send_seq_num += 2;
 721
 722         saved_seq = reply_seq_number;
 723         simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number, calc_md5_mac);
 724
 725         server_sent_mac = (unsigned char *)&inbuf[smb_ss_field];
 726         good = (memcmp(server_sent_mac, calc_md5_mac, 8) == 0);
 727
 728         if (!good) {
 729
 730                 if (saved_seq) {
 731                         DEBUG(0, ("srv_check_incoming_message: BAD SIG: seq %u wanted SMB signature of\n",
 732                                         (unsigned int)saved_seq));
 733                         dump_data(5, (const char *)calc_md5_mac, 8);
 734
 735                         DEBUG(0, ("srv_check_incoming_message: BAD SIG: seq %u got SMB signature of\n",
 736                                                 (unsigned int)reply_seq_number));
 737                         dump_data(5, (const char *)server_sent_mac, 8);
 738                 }
 739
 740 #if 1 /* JRATEST */
 741                 {
 742                         int i;
 743                         reply_seq_number -= 5;
 744                         for (i = 0; i < 10; i++, reply_seq_number++) {
 745                                 simple_packet_signature(data, (const unsigned char *)inbuf, reply_seq_number, calc_md5_mac);
 746                                 if (memcmp(server_sent_mac, calc_md5_mac, 8) == 0) {
 747                                         DEBUG(0,("srv_check_incoming_message: out of seq. seq num %u matches. \
 748 We were expecting seq %u\n", reply_seq_number, saved_seq ));
 749                                         break;
 750                                 }
 751                         }
 752                 }
 753 #endif /* JRATEST */
 754
 755         } else {
 756                 DEBUG(10, ("srv_check_incoming_message: seq %u: (current is %u) got good SMB signature of\n", (unsigned int)reply_seq_number, (unsigned int)data->send_seq_num));
 757                 dump_data(10, (const char *)server_sent_mac, 8);
 758         }
 759
 760         return (signing_good(inbuf, si, good, saved_seq, must_be_ok));
 761 }
 762
 763 /***********************************************************
 764  SMB signing - server API's.
 765 ************************************************************/
 766
 767 static struct smb_sign_info srv_sign_info = {
 768         null_sign_outgoing_message,
 769         null_check_incoming_message,
 770         null_free_signing_context,
 771         NULL,
 772         False,
 773         False,
 774         False,
 775         False
 776 };
 777
 778 /***********************************************************
 779  Turn signing off or on for oplock break code.
 780 ************************************************************/
 781
 782 BOOL srv_oplock_set_signing(BOOL onoff)
 783 {
 784         BOOL ret = srv_sign_info.doing_signing;
 785         srv_sign_info.doing_signing = onoff;
 786         return ret;
 787 }
 788
 789 /***********************************************************
 790  Called to validate an incoming packet from the client.
 791 ************************************************************/
 792
 793 BOOL srv_check_sign_mac(char *inbuf, BOOL must_be_ok)
 794 {
 795         /* Check if it's a session keepalive. */
 796         if(CVAL(inbuf,0) == SMBkeepalive)
 797                 return True;
 798
 799         return srv_sign_info.check_incoming_message(inbuf, &srv_sign_info, must_be_ok);
 800 }
 801
 802 /***********************************************************
 803  Called to sign an outgoing packet to the client.
 804 ************************************************************/
 805
 806 void srv_calculate_sign_mac(char *outbuf)
 807 {
 808         /* Check if it's a session keepalive. */
 809         /* JRA Paranioa test - do we ever generate these in the server ? */
 810         if(CVAL(outbuf,0) == SMBkeepalive)
 811                 return;
 812
 813         srv_sign_info.sign_outgoing_message(outbuf, &srv_sign_info);
 814 }
 815
 816 /***********************************************************
 817  Called by server to defer an outgoing packet.
 818 ************************************************************/
 819
 820 void srv_defer_sign_response(uint16 mid)
 821 {
 822         struct smb_basic_signing_context *data;
 823
 824         if (!srv_sign_info.doing_signing)
 825                 return;
 826
 827         data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
 828
 829         if (!data)
 830                 return;
 831
 832         /*
 833          * Ensure we only store this mid reply once...
 834          */
 835
 836         store_sequence_for_reply(&data->outstanding_packet_list, mid,
 837                                  data->send_seq_num-1);
 838 }
 839
 840 /***********************************************************
 841  Called to remove sequence records when a deferred packet is
 842  cancelled by mid. This should never find one....
 843 ************************************************************/
 844
 845 void srv_cancel_sign_response(uint16 mid)
 846 {
 847         struct smb_basic_signing_context *data;
 848         uint32 dummy_seq;
 849
 850         if (!srv_sign_info.doing_signing)
 851                 return;
 852
 853         data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
 854
 855         if (!data)
 856                 return;
 857
 858         DEBUG(10,("srv_cancel_sign_response: for mid %u\n", (unsigned int)mid ));
 859
 860         while (get_sequence_for_reply(&data->outstanding_packet_list, mid, &dummy_seq))
 861                 ;
 862
 863         /* cancel doesn't send a reply so doesn't burn a sequence number. */
 864         data->send_seq_num -= 1;
 865 }
 866
 867 /***********************************************************
 868  Called by server negprot when signing has been negotiated.
 869 ************************************************************/
 870
 871 void srv_set_signing_negotiated(void)
 872 {
 873         srv_sign_info.allow_smb_signing = True;
 874         srv_sign_info.negotiated_smb_signing = True;
 875         if (lp_server_signing() == Required)
 876                 srv_sign_info.mandatory_signing = True;
 877
 878         srv_sign_info.sign_outgoing_message = temp_sign_outgoing_message;
 879         srv_sign_info.check_incoming_message = temp_check_incoming_message;
 880         srv_sign_info.free_signing_context = temp_free_signing_context;
 881 }
 882
 883 /***********************************************************
 884  Returns whether signing is active. We can't use sendfile or raw
 885  reads/writes if it is.
 886 ************************************************************/
 887
 888 BOOL srv_is_signing_active(void)
 889 {
 890         return srv_sign_info.doing_signing;
 891 }
 892
 893
 894 /***********************************************************
 895  Returns whether signing is negotiated. We can't use it unless it was
 896  in the negprot.
 897 ************************************************************/
 898
 899 BOOL srv_is_signing_negotiated(void)
 900 {
 901         return srv_sign_info.negotiated_smb_signing;
 902 }
 903
 904 /***********************************************************
 905  Returns whether signing is actually happening
 906 ************************************************************/
 907
 908 BOOL srv_signing_started(void)
 909 {
 910         struct smb_basic_signing_context *data;
 911
 912         if (!srv_sign_info.doing_signing) {
 913                 return False;
 914         }
 915
 916         data = (struct smb_basic_signing_context *)srv_sign_info.signing_context;
 917         if (!data)
 918                 return False;
 919
 920         if (data->send_seq_num == 0) {
 921                 return False;
 922         }
 923
 924         return True;
 925 }
 926
 927 /***********************************************************
 928  Turn on signing from this packet onwards.
 929 ************************************************************/
 930
 931 void srv_set_signing(const DATA_BLOB user_session_key, const DATA_BLOB response)
 932 {
 933         struct smb_basic_signing_context *data;
 934
 935         if (!user_session_key.length)
 936                 return;
 937
 938         if (!srv_sign_info.negotiated_smb_signing && !srv_sign_info.mandatory_signing) {
 939                 DEBUG(5,("srv_set_signing: signing negotiated = %u, mandatory_signing = %u. Not allowing smb signing.\n",
 940                         (unsigned int)srv_sign_info.negotiated_smb_signing,
 941                         (unsigned int)srv_sign_info.mandatory_signing ));
 942                 return;
 943         }
 944
 945         /* Once we've turned on, ignore any more sessionsetups. */
 946         if (srv_sign_info.doing_signing) {
 947                 return;
 948         }
 949
 950         if (srv_sign_info.free_signing_context)
 951                 srv_sign_info.free_signing_context(&srv_sign_info);
 952
 953         srv_sign_info.doing_signing = True;
 954
 955         data = SMB_XMALLOC_P(struct smb_basic_signing_context);
 956         memset(data, '\0', sizeof(*data));
 957
 958         srv_sign_info.signing_context = data;
 959
 960         data->mac_key = data_blob(NULL, response.length + user_session_key.length);
 961
 962         memcpy(&data->mac_key.data[0], user_session_key.data, user_session_key.length);
 963         if (response.length)
 964                 memcpy(&data->mac_key.data[user_session_key.length],response.data, response.length);
 965
 966         dump_data_pw("MAC ssession key is:\n", data->mac_key.data, data->mac_key.length);
 967
 968         DEBUG(3,("srv_set_signing: turning on SMB signing: signing negotiated = %s, mandatory_signing = %s.\n",
 969                                 BOOLSTR(srv_sign_info.negotiated_smb_signing),
 970                                 BOOLSTR(srv_sign_info.mandatory_signing) ));
 971
 972         /* Initialise the sequence number */
 973         data->send_seq_num = 0;
 974
 975         /* Initialise the list of outstanding packets */
 976         data->outstanding_packet_list = NULL;
 977
 978         srv_sign_info.sign_outgoing_message = srv_sign_outgoing_message;
 979         srv_sign_info.check_incoming_message = srv_check_incoming_message;
 980         srv_sign_info.free_signing_context = simple_free_signing_context;
 981 }