source/nmbd/nmbd_incomingrequests.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    NBT netbios routines and daemon - version 2
   4    Copyright (C) Andrew Tridgell 1994-1998
   5    Copyright (C) Luke Kenneth Casson Leighton 1994-1998
   6    Copyright (C) Jeremy Allison 1994-2003
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21
  22    This file contains all the code to process NetBIOS requests coming
  23    in on port 137. It does not deal with the code needed to service
  24    WINS server requests, but only broadcast and unicast requests.
  25
  26 */
  27
  28 #include "includes.h"
  29
  30 /****************************************************************************
  31 Send a name release response.
  32 **************************************************************************/
  33
  34 static void send_name_release_response(int rcode, struct packet_struct *p)
  35 {
  36         struct nmb_packet *nmb = &p->packet.nmb;
  37         char rdata[6];
  38
  39         memcpy(&rdata[0], &nmb->additional->rdata[0], 6);
  40
  41         reply_netbios_packet(p,                       /* Packet to reply to. */
  42                         rcode,                        /* Result code. */
  43                         NMB_REL,                      /* nmbd type code. */
  44                         NMB_NAME_RELEASE_OPCODE,      /* opcode. */
  45                         0,                            /* ttl. */
  46                         rdata,                        /* data to send. */
  47                         6);                           /* data length. */
  48 }
  49
  50 /****************************************************************************
  51 Process a name release packet on a broadcast subnet.
  52 Ignore it if it's not one of our names.
  53 ****************************************************************************/
  54
  55 void process_name_release_request(struct subnet_record *subrec,
  56                                   struct packet_struct *p)
  57 {
  58         struct nmb_packet *nmb = &p->packet.nmb;
  59         struct in_addr owner_ip;
  60         struct nmb_name *question = &nmb->question.question_name;
  61         nstring qname;
  62         BOOL bcast = nmb->header.nm_flags.bcast;
  63         uint16 nb_flags = get_nb_flags(nmb->additional->rdata);
  64         BOOL group = (nb_flags & NB_GROUP) ? True : False;
  65         struct name_record *namerec;
  66         int rcode = 0;
  67
  68         putip((char *)&owner_ip,&nmb->additional->rdata[2]);
  69
  70         if(!bcast) {
  71                 /* We should only get broadcast name release packets here.
  72                    Anyone trying to release unicast should be going to a WINS
  73                    server. If the code gets here, then either we are not a wins
  74                    server and they sent it anyway, or we are a WINS server and
  75                    the request was malformed. Either way, log an error here.
  76                    and send an error reply back.
  77                 */
  78                 DEBUG(0,("process_name_release_request: unicast name release request \
  79 received for name %s from IP %s on subnet %s. Error - should be sent to WINS server\n",
  80                         nmb_namestr(question), inet_ntoa(owner_ip), subrec->subnet_name));
  81
  82                 send_name_release_response(FMT_ERR, p);
  83                 return;
  84         }
  85
  86         DEBUG(3,("process_name_release_request: Name release on name %s, \
  87 subnet %s from owner IP %s\n",
  88                 nmb_namestr(&nmb->question.question_name),
  89                 subrec->subnet_name, inet_ntoa(owner_ip)));
  90
  91         /* If someone is releasing a broadcast group name, just ignore it. */
  92         if( group && !ismyip(owner_ip) )
  93                 return;
  94
  95         /*
  96          * Code to work around a bug in FTP OnNet software NBT implementation.
  97          * They do a broadcast name release for WORKGROUP<0> and WORKGROUP<1e>
  98          * names and *don't set the group bit* !!!!!
  99          */
 100
 101         pull_ascii_nstring(qname, question->name);
 102         if( !group && !ismyip(owner_ip) && strequal(qname, lp_workgroup()) &&
 103                         ((question->name_type == 0x0) || (question->name_type == 0x1e))) {
 104                 DEBUG(6,("process_name_release_request: FTP OnNet bug workaround. Ignoring \
 105 group release name %s from IP %s on subnet %s with no group bit set.\n",
 106                         nmb_namestr(question), inet_ntoa(owner_ip), subrec->subnet_name ));
 107                 return;
 108         }
 109
 110         namerec = find_name_on_subnet(subrec, question, FIND_ANY_NAME);
 111
 112         /* We only care about someone trying to release one of our names. */
 113         if( namerec && ( (namerec->data.source == SELF_NAME)
 114                         || (namerec->data.source == PERMANENT_NAME) ) ) {
 115                 rcode = ACT_ERR;
 116                 DEBUG(0, ("process_name_release_request: Attempt to release name %s from IP %s \
 117 on subnet %s being rejected as it is one of our names.\n",
 118                 nmb_namestr(&nmb->question.question_name), inet_ntoa(owner_ip), subrec->subnet_name));
 119         }
 120
 121         if(rcode == 0)
 122                 return;
 123
 124         /* Send a NAME RELEASE RESPONSE (pos/neg) see rfc1002.txt 4.2.10-11 */
 125         send_name_release_response(rcode, p);
 126 }
 127
 128 /****************************************************************************
 129 Send a name registration response.
 130 **************************************************************************/
 131
 132 static void send_name_registration_response(int rcode, int ttl, struct packet_struct *p)
 133 {
 134         struct nmb_packet *nmb = &p->packet.nmb;
 135         char rdata[6];
 136
 137         memcpy(&rdata[0], &nmb->additional->rdata[0], 6);
 138
 139         reply_netbios_packet(p,                                /* Packet to reply to. */
 140                                 rcode,                         /* Result code. */
 141                                 NMB_REG,                       /* nmbd type code. */
 142                                 NMB_NAME_REG_OPCODE,           /* opcode. */
 143                                 ttl,                           /* ttl. */
 144                                 rdata,                         /* data to send. */
 145                                 6);                            /* data length. */
 146 }
 147
 148 /****************************************************************************
 149 Process a name refresh request on a broadcast subnet.
 150 **************************************************************************/
 151
 152 void process_name_refresh_request(struct subnet_record *subrec,
 153                                   struct packet_struct *p)
 154 {
 155         struct nmb_packet *nmb = &p->packet.nmb;
 156         struct nmb_name *question = &nmb->question.question_name;
 157         BOOL bcast = nmb->header.nm_flags.bcast;
 158         struct in_addr from_ip;
 159
 160         putip((char *)&from_ip,&nmb->additional->rdata[2]);
 161
 162         if(!bcast) {
 163                 /* We should only get broadcast name refresh packets here.
 164                    Anyone trying to refresh unicast should be going to a WINS
 165                    server. If the code gets here, then either we are not a wins
 166                    server and they sent it anyway, or we are a WINS server and
 167                    the request was malformed. Either way, log an error here.
 168                    and send an error reply back.
 169                 */
 170                 DEBUG(0,("process_name_refresh_request: unicast name registration request \
 171 received for name %s from IP %s on subnet %s.\n",
 172                         nmb_namestr(question), inet_ntoa(from_ip), subrec->subnet_name));
 173                 DEBUG(0,("Error - should be sent to WINS server\n"));
 174
 175                 send_name_registration_response(FMT_ERR, 0, p);
 176                 return;
 177         }
 178
 179         /* Just log a message. We really don't care about broadcast name refreshes. */
 180
 181         DEBUG(3,("process_name_refresh_request: Name refresh for name %s \
 182 IP %s on subnet %s\n", nmb_namestr(question), inet_ntoa(from_ip), subrec->subnet_name));
 183 }
 184
 185 /****************************************************************************
 186 Process a name registration request on a broadcast subnet.
 187 **************************************************************************/
 188
 189 void process_name_registration_request(struct subnet_record *subrec,
 190                                        struct packet_struct *p)
 191 {
 192         struct nmb_packet *nmb = &p->packet.nmb;
 193         struct nmb_name *question = &nmb->question.question_name;
 194         BOOL bcast = nmb->header.nm_flags.bcast;
 195         uint16 nb_flags = get_nb_flags(nmb->additional->rdata);
 196         BOOL group = (nb_flags & NB_GROUP) ? True : False;
 197         struct name_record *namerec = NULL;
 198         int ttl = nmb->additional->ttl;
 199         struct in_addr from_ip;
 200
 201         putip((char *)&from_ip,&nmb->additional->rdata[2]);
 202
 203         if(!bcast) {
 204                 /* We should only get broadcast name registration packets here.
 205                    Anyone trying to register unicast should be going to a WINS
 206                    server. If the code gets here, then either we are not a wins
 207                    server and they sent it anyway, or we are a WINS server and
 208                    the request was malformed. Either way, log an error here.
 209                    and send an error reply back.
 210                 */
 211                 DEBUG(0,("process_name_registration_request: unicast name registration request \
 212 received for name %s from IP %s on subnet %s. Error - should be sent to WINS server\n",
 213                         nmb_namestr(question), inet_ntoa(from_ip), subrec->subnet_name));
 214
 215                 send_name_registration_response(FMT_ERR, 0, p);
 216                 return;
 217         }
 218
 219         DEBUG(3,("process_name_registration_request: Name registration for name %s \
 220 IP %s on subnet %s\n", nmb_namestr(question), inet_ntoa(from_ip), subrec->subnet_name));
 221
 222         /* See if the name already exists. */
 223         namerec = find_name_on_subnet(subrec, question, FIND_ANY_NAME);
 224
 225         /*
 226          * If the name being registered exists and is a WINS_PROXY_NAME
 227          * then delete the WINS proxy name entry so we don't reply erroneously
 228          * later to queries.
 229          */
 230
 231         if((namerec != NULL) && (namerec->data.source == WINS_PROXY_NAME)) {
 232                 remove_name_from_namelist( subrec, namerec );
 233                 namerec = NULL;
 234         }
 235
 236         if (!group) {
 237                 /* Unique name. */
 238
 239                 if( (namerec != NULL)
 240                                 && ( (namerec->data.source == SELF_NAME)
 241                                 || (namerec->data.source == PERMANENT_NAME)
 242                                 || NAME_GROUP(namerec) ) ) {
 243                         /* No-one can register one of Samba's names, nor can they
 244                                 register a name that's a group name as a unique name */
 245
 246                         send_name_registration_response(ACT_ERR, 0, p);
 247                         return;
 248                 } else if(namerec != NULL) {
 249                         /* Update the namelist record with the new information. */
 250                         namerec->data.ip[0] = from_ip;
 251                         update_name_ttl(namerec, ttl);
 252
 253                         DEBUG(3,("process_name_registration_request: Updated name record %s \
 254 with IP %s on subnet %s\n",nmb_namestr(&namerec->name),inet_ntoa(from_ip), subrec->subnet_name));
 255                         return;
 256                 }
 257         } else {
 258                 /* Group name. */
 259
 260                 if( (namerec != NULL)
 261                                 && !NAME_GROUP(namerec)
 262                                 && ( (namerec->data.source == SELF_NAME)
 263                                 || (namerec->data.source == PERMANENT_NAME) ) ) {
 264                         /* Disallow group names when we have a unique name. */
 265                         send_name_registration_response(ACT_ERR, 0, p);
 266                         return;
 267                 }
 268         }
 269 }
 270
 271 /****************************************************************************
 272 This is used to sort names for a name status into a sensible order.
 273 We put our own names first, then in alphabetical order.
 274 **************************************************************************/
 275
 276 static int status_compare(char *n1,char *n2)
 277 {
 278         nstring name1, name2;
 279         int l1,l2,l3;
 280
 281         pull_ascii_nstring(name1, n1);
 282         pull_ascii_nstring(name2, n2);
 283         n1 = name1;
 284         n2 = name2;
 285
 286         /* It's a bit tricky because the names are space padded */
 287         for (l1=0;l1<15 && n1[l1] && n1[l1] != ' ';l1++)
 288                 ;
 289         for (l2=0;l2<15 && n2[l2] && n2[l2] != ' ';l2++)
 290                 ;
 291         l3 = strlen(global_myname());
 292
 293         if ((l1==l3) && strncmp(n1,global_myname(),l3) == 0 &&
 294                         (l2!=l3 || strncmp(n2,global_myname(),l3) != 0))
 295                 return -1;
 296
 297         if ((l2==l3) && strncmp(n2,global_myname(),l3) == 0 &&
 298                         (l1!=l3 || strncmp(n1,global_myname(),l3) != 0))
 299                 return 1;
 300
 301         return memcmp(n1,n2,sizeof(nstring));
 302 }
 303
 304 /****************************************************************************
 305   Process a node status query
 306   ****************************************************************************/
 307
 308 void process_node_status_request(struct subnet_record *subrec, struct packet_struct *p)
 309 {
 310         struct nmb_packet *nmb = &p->packet.nmb;
 311         nstring qname;
 312         int ques_type = nmb->question.question_name.name_type;
 313         char rdata[MAX_DGRAM_SIZE];
 314         char *countptr, *buf, *bufend, *buf0;
 315         int names_added,i;
 316         struct name_record *namerec;
 317
 318         pull_ascii_nstring(qname, nmb->question.question_name.name);
 319
 320         DEBUG(3,("process_node_status_request: status request for name %s from IP %s on \
 321 subnet %s.\n", nmb_namestr(&nmb->question.question_name), inet_ntoa(p->ip), subrec->subnet_name));
 322
 323         if((namerec = find_name_on_subnet(subrec, &nmb->question.question_name, FIND_SELF_NAME)) == 0) {
 324                 DEBUG(1,("process_node_status_request: status request for name %s from IP %s on \
 325 subnet %s - name not found.\n", nmb_namestr(&nmb->question.question_name),
 326                         inet_ntoa(p->ip), subrec->subnet_name));
 327
 328                 return;
 329         }
 330
 331         /* this is not an exact calculation. the 46 is for the stats buffer
 332                 and the 60 is to leave room for the header etc */
 333         bufend = &rdata[MAX_DGRAM_SIZE] - (18 + 46 + 60);
 334         countptr = buf = rdata;
 335         buf += 1;
 336         buf0 = buf;
 337
 338         names_added = 0;
 339
 340         namerec = (struct name_record *)ubi_trFirst( subrec->namelist );
 341
 342         while (buf < bufend) {
 343                 if( (namerec->data.source == SELF_NAME) || (namerec->data.source == PERMANENT_NAME) ) {
 344                         int name_type = namerec->name.name_type;
 345                         nstring name;
 346
 347                         pull_ascii_nstring(name, namerec->name.name);
 348                         strupper_m(name);
 349                         if (!strequal(name,"*") &&
 350                                         !strequal(name,"__SAMBA__") &&
 351                                         (name_type < 0x1b || name_type >= 0x20 ||
 352                                         ques_type < 0x1b || ques_type >= 0x20 ||
 353                                         strequal(qname, name))) {
 354                                 /* Start with the name. */
 355                                 nstring tmp_name;
 356                                 memset(tmp_name,'\0',sizeof(tmp_name));
 357                                 snprintf(tmp_name, sizeof(tmp_name), "%-15.15s",name);
 358                                 push_ascii_nstring(buf, tmp_name);
 359
 360                                 /* Put the name type and netbios flags in the buffer. */
 361
 362                                 buf[15] = name_type;
 363                                 set_nb_flags( &buf[16],namerec->data.nb_flags );
 364                                 buf[16] |= NB_ACTIVE; /* all our names are active */
 365
 366                                 buf += 18;
 367
 368                                 names_added++;
 369                         }
 370                 }
 371
 372                 /* Remove duplicate names. */
 373                 if (names_added > 1) {
 374                         qsort( buf0, names_added, 18, QSORT_CAST status_compare );
 375                 }
 376
 377                 for( i=1; i < names_added ; i++ ) {
 378                         if (memcmp(buf0 + 18*i,buf0 + 18*(i-1),16) == 0) {
 379                                 names_added--;
 380                                 if (names_added == i)
 381                                         break;
 382                                 memmove(buf0 + 18*i,buf0 + 18*(i+1),18*(names_added-i));
 383                                 i--;
 384                         }
 385                 }
 386
 387                 buf = buf0 + 18*names_added;
 388
 389                 namerec = (struct name_record *)ubi_trNext( namerec );
 390
 391                 if (!namerec) {
 392                         /* End of the subnet specific name list. Now
 393                                 add the names on the unicast subnet . */
 394                         struct subnet_record *uni_subrec = unicast_subnet;
 395
 396                         if (uni_subrec != subrec) {
 397                                 subrec = uni_subrec;
 398                                 namerec = (struct name_record *)ubi_trFirst( subrec->namelist );
 399                         }
 400                 }
 401                 if (!namerec)
 402                         break;
 403
 404         }
 405
 406         SCVAL(countptr,0,names_added);
 407
 408         /* We don't send any stats as they could be used to attack
 409                 the protocol. */
 410         memset(buf,'\0',46);
 411
 412         buf += 46;
 413
 414         /* Send a NODE STATUS RESPONSE */
 415         reply_netbios_packet(p,                               /* Packet to reply to. */
 416                                 0,                            /* Result code. */
 417                                 NMB_STATUS,                   /* nmbd type code. */
 418                                 NMB_NAME_QUERY_OPCODE,        /* opcode. */
 419                                 0,                            /* ttl. */
 420                                 rdata,                        /* data to send. */
 421                                 PTR_DIFF(buf,rdata));         /* data length. */
 422 }
 423
 424
 425 /***************************************************************************
 426 Process a name query.
 427
 428 For broadcast name queries:
 429
 430   - Only reply if the query is for one of YOUR names.
 431   - NEVER send a negative response to a broadcast query.
 432
 433 ****************************************************************************/
 434
 435 void process_name_query_request(struct subnet_record *subrec, struct packet_struct *p)
 436 {
 437         struct nmb_packet *nmb = &p->packet.nmb;
 438         struct nmb_name *question = &nmb->question.question_name;
 439         int name_type = question->name_type;
 440         BOOL bcast = nmb->header.nm_flags.bcast;
 441         int ttl=0;
 442         int rcode = 0;
 443         char *prdata = NULL;
 444         char rdata[6];
 445         BOOL success = False;
 446         struct name_record *namerec = NULL;
 447         int reply_data_len = 0;
 448         int i;
 449
 450         DEBUG(3,("process_name_query_request: Name query from %s on subnet %s for name %s\n",
 451                  inet_ntoa(p->ip), subrec->subnet_name, nmb_namestr(question)));
 452
 453         /* Look up the name in the cache - if the request is a broadcast request that
 454            came from a subnet we don't know about then search all the broadcast subnets
 455            for a match (as we don't know what interface the request came in on). */
 456
 457         if(subrec == remote_broadcast_subnet)
 458                 namerec = find_name_for_remote_broadcast_subnet( question, FIND_ANY_NAME);
 459         else
 460                 namerec = find_name_on_subnet(subrec, question, FIND_ANY_NAME);
 461
 462         /* Check if it is a name that expired */
 463         if (namerec &&
 464             ((namerec->data.death_time != PERMANENT_TTL) &&
 465              (namerec->data.death_time < p->timestamp))) {
 466                 DEBUG(5,("process_name_query_request: expired name %s\n", nmb_namestr(&namerec->name)));
 467                 namerec = NULL;
 468         }
 469
 470         if (namerec) {
 471                 /*
 472                  * Always respond to unicast queries.
 473                  * Don't respond to broadcast queries unless the query is for
 474                  * a name we own, a Primary Domain Controller name, or a WINS_PROXY
 475                  * name with type 0 or 0x20. WINS_PROXY names are only ever added
 476                  * into the namelist if we were configured as a WINS proxy.
 477                  */
 478
 479                 if (!bcast ||
 480                     (bcast && ((name_type == 0x1b) ||
 481                                (namerec->data.source == SELF_NAME) ||
 482                                (namerec->data.source == PERMANENT_NAME) ||
 483                                ((namerec->data.source == WINS_PROXY_NAME) &&
 484                                 ((name_type == 0) || (name_type == 0x20)))))) {
 485                         /* The requested name is a directed query, or it's SELF or PERMANENT or WINS_PROXY,
 486                            or it's a Domain Master type. */
 487
 488                         /*
 489                          * If this is a WINS_PROXY_NAME, then ceck that none of the IP
 490                          * addresses we are returning is on the same broadcast subnet
 491                          * as the requesting packet. If it is then don't reply as the
 492                          * actual machine will be replying also and we don't want two
 493                          * replies to a broadcast query.
 494                          */
 495
 496                         if (namerec->data.source == WINS_PROXY_NAME) {
 497                                 for( i = 0; i < namerec->data.num_ips; i++) {
 498                                         if (same_net(namerec->data.ip[i], subrec->myip, subrec->mask_ip)) {
 499                                                 DEBUG(5,("process_name_query_request: name %s is a WINS proxy name and is also on the same subnet (%s) as the requestor. Not replying.\n",
 500                                                          nmb_namestr(&namerec->name), subrec->subnet_name ));
 501                                                 return;
 502                                         }
 503                                 }
 504                         }
 505
 506                         ttl = (namerec->data.death_time != PERMANENT_TTL) ?
 507                                 namerec->data.death_time - p->timestamp : lp_max_ttl();
 508
 509                         /* Copy all known ip addresses into the return data. */
 510                         /* Optimise for the common case of one IP address so
 511                            we don't need a malloc. */
 512
 513                         if (namerec->data.num_ips == 1) {
 514                                 prdata = rdata;
 515                         } else {
 516                                 if ((prdata = (char *)malloc( namerec->data.num_ips * 6 )) == NULL) {
 517                                         DEBUG(0,("process_name_query_request: malloc fail !\n"));
 518                                         return;
 519                                 }
 520                         }
 521
 522                         for (i = 0; i < namerec->data.num_ips; i++) {
 523                                 set_nb_flags(&prdata[i*6],namerec->data.nb_flags);
 524                                 putip((char *)&prdata[2+(i*6)], &namerec->data.ip[i]);
 525                         }
 526
 527                         sort_query_replies(prdata, i, p->ip);
 528
 529                         reply_data_len = namerec->data.num_ips * 6;
 530                         success = True;
 531                 }
 532         }
 533
 534         /*
 535          * If a machine is broadcasting a name lookup request and we have lp_wins_proxy()
 536          * set we should initiate a WINS query here. On success we add the resolved name
 537          * into our namelist with a type of WINS_PROXY_NAME and then reply to the query.
 538          */
 539
 540         if(!success && (namerec == NULL) && we_are_a_wins_client() && lp_wins_proxy() &&
 541            bcast && (subrec != remote_broadcast_subnet)) {
 542                 make_wins_proxy_name_query_request( subrec, p, question );
 543                 return;
 544         }
 545
 546         if (!success && bcast) {
 547                 if(prdata != rdata)
 548                         SAFE_FREE(prdata);
 549                 return; /* Never reply with a negative response to broadcasts. */
 550         }
 551
 552         /*
 553          * Final check. From observation, if a unicast packet is sent
 554          * to a non-WINS server with the recursion desired bit set
 555          * then never send a negative response.
 556          */
 557
 558         if(!success && !bcast && nmb->header.nm_flags.recursion_desired) {
 559                 if(prdata != rdata)
 560                         SAFE_FREE(prdata);
 561                 return;
 562         }
 563
 564         if (success) {
 565                 rcode = 0;
 566                 DEBUG(3,("OK\n"));
 567         } else {
 568                 rcode = NAM_ERR;
 569                 DEBUG(3,("UNKNOWN\n"));
 570         }
 571
 572         /* See rfc1002.txt 4.2.13. */
 573
 574         reply_netbios_packet(p,                              /* Packet to reply to. */
 575                              rcode,                          /* Result code. */
 576                              NMB_QUERY,                      /* nmbd type code. */
 577                              NMB_NAME_QUERY_OPCODE,          /* opcode. */
 578                              ttl,                            /* ttl. */
 579                              prdata,                         /* data to send. */
 580                              reply_data_len);                /* data length. */
 581
 582         if(prdata != rdata)
 583                 SAFE_FREE(prdata);
 584 }