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