source3/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 3 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, see <http://www.gnu.org/licenses/>.
  20
  21    This file contains all the code to process NetBIOS requests coming
  22    in on port 137. It does not deal with the code needed to service
  23    WINS server requests, but only broadcast and unicast requests.
  24
  25 */
  26
  27 #include "includes.h"
  28 #include "nmbd/nmbd.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         unstring 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_v4(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, sizeof(qname), question->name);
 102         if( !group && !ismyip_v4(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         unstring name1, name2;
 279         int l1,l2,l3;
 280
 281         memset(name1, '\0', sizeof(name1));
 282         memset(name2, '\0', sizeof(name2));
 283         pull_ascii_nstring(name1, sizeof(name1), n1);
 284         pull_ascii_nstring(name2, sizeof(name2), n2);
 285         n1 = name1;
 286         n2 = name2;
 287
 288         /* It's a bit tricky because the names are space padded */
 289         for (l1=0;l1<15 && n1[l1] && n1[l1] != ' ';l1++)
 290                 ;
 291         for (l2=0;l2<15 && n2[l2] && n2[l2] != ' ';l2++)
 292                 ;
 293         l3 = strlen(lp_netbios_name());
 294
 295         if ((l1==l3) && strncmp(n1,lp_netbios_name(),l3) == 0 &&
 296                         (l2!=l3 || strncmp(n2,lp_netbios_name(),l3) != 0))
 297                 return -1;
 298
 299         if ((l2==l3) && strncmp(n2,lp_netbios_name(),l3) == 0 &&
 300                         (l1!=l3 || strncmp(n1,lp_netbios_name(),l3) != 0))
 301                 return 1;
 302
 303         return memcmp(n1,n2,sizeof(name1));
 304 }
 305
 306 /****************************************************************************
 307   Process a node status query
 308   ****************************************************************************/
 309
 310 void process_node_status_request(struct subnet_record *subrec, struct packet_struct *p)
 311 {
 312         struct nmb_packet *nmb = &p->packet.nmb;
 313         unstring qname;
 314         int ques_type = nmb->question.question_name.name_type;
 315         char rdata[MAX_DGRAM_SIZE];
 316         char *countptr, *buf, *bufend, *buf0;
 317         int names_added,i;
 318         struct name_record *namerec = NULL;
 319
 320         pull_ascii_nstring(qname, sizeof(qname), nmb->question.question_name.name);
 321
 322         DEBUG(3,("process_node_status_request: status request for name %s from IP %s on \
 323 subnet %s.\n", nmb_namestr(&nmb->question.question_name), inet_ntoa(p->ip), subrec->subnet_name));
 324
 325         if(find_name_on_subnet(subrec, &nmb->question.question_name, FIND_SELF_NAME) == 0) {
 326                 DEBUG(1,("process_node_status_request: status request for name %s from IP %s on \
 327 subnet %s - name not found.\n", nmb_namestr(&nmb->question.question_name),
 328                         inet_ntoa(p->ip), subrec->subnet_name));
 329
 330                 return;
 331         }
 332
 333         /* this is not an exact calculation. the 46 is for the stats buffer
 334                 and the 60 is to leave room for the header etc */
 335         bufend = &rdata[MAX_DGRAM_SIZE-1] - (18 + 46 + 60);
 336         countptr = buf = rdata;
 337         buf += 1;
 338         buf0 = buf;
 339
 340         names_added = 0;
 341
 342         namerec = subrec->namelist;
 343
 344         while (buf < bufend) {
 345                 if( (namerec->data.source == SELF_NAME) || (namerec->data.source == PERMANENT_NAME) ) {
 346                         int name_type = namerec->name.name_type;
 347                         unstring name;
 348
 349                         pull_ascii_nstring(name, sizeof(name), namerec->name.name);
 350                         strupper_m(name);
 351                         if (!strequal(name,"*") &&
 352                                         !strequal(name,"__SAMBA__") &&
 353                                         (name_type < 0x1b || name_type >= 0x20 ||
 354                                         ques_type < 0x1b || ques_type >= 0x20 ||
 355                                         strequal(qname, name))) {
 356                                 /* Start with the name. */
 357                                 size_t len;
 358                                 push_ascii_nstring(buf, name);
 359                                 len = strlen(buf);
 360                                 memset(buf + len, ' ', MAX_NETBIOSNAME_LEN - len - 1);
 361                                 buf[MAX_NETBIOSNAME_LEN - 1] = '\0';
 362
 363                                 /* Put the name type and netbios flags in the buffer. */
 364
 365                                 buf[15] = name_type;
 366                                 set_nb_flags( &buf[16],namerec->data.nb_flags );
 367                                 buf[16] |= NB_ACTIVE; /* all our names are active */
 368
 369                                 buf += 18;
 370
 371                                 names_added++;
 372                         }
 373                 }
 374
 375                 /* Remove duplicate names. */
 376                 if (names_added > 1) {
 377                         /* TODO: should use a real type and
 378                            TYPESAFE_QSORT() */
 379                         qsort( buf0, names_added, 18, QSORT_CAST status_compare );
 380                 }
 381
 382                 for( i=1; i < names_added ; i++ ) {
 383                         if (memcmp(buf0 + 18*i,buf0 + 18*(i-1),16) == 0) {
 384                                 names_added--;
 385                                 if (names_added == i)
 386                                         break;
 387                                 memmove(buf0 + 18*i,buf0 + 18*(i+1),18*(names_added-i));
 388                                 i--;
 389                         }
 390                 }
 391
 392                 buf = buf0 + 18*names_added;
 393
 394                 namerec = namerec->next;
 395
 396                 if (!namerec) {
 397                         /* End of the subnet specific name list. Now
 398                                 add the names on the unicast subnet . */
 399                         struct subnet_record *uni_subrec = unicast_subnet;
 400
 401                         if (uni_subrec != subrec) {
 402                                 subrec = uni_subrec;
 403                                 namerec = subrec->namelist;
 404                         }
 405                 }
 406                 if (!namerec)
 407                         break;
 408
 409         }
 410
 411         SCVAL(countptr,0,names_added);
 412
 413         /* We don't send any stats as they could be used to attack
 414                 the protocol. */
 415         memset(buf,'\0',46);
 416
 417         buf += 46;
 418
 419         /* Send a NODE STATUS RESPONSE */
 420         reply_netbios_packet(p,                               /* Packet to reply to. */
 421                                 0,                            /* Result code. */
 422                                 NMB_STATUS,                   /* nmbd type code. */
 423                                 NMB_NAME_QUERY_OPCODE,        /* opcode. */
 424                                 0,                            /* ttl. */
 425                                 rdata,                        /* data to send. */
 426                                 PTR_DIFF(buf,rdata));         /* data length. */
 427 }
 428
 429
 430 /***************************************************************************
 431 Process a name query.
 432
 433 For broadcast name queries:
 434
 435   - Only reply if the query is for one of YOUR names.
 436   - NEVER send a negative response to a broadcast query.
 437
 438 ****************************************************************************/
 439
 440 void process_name_query_request(struct subnet_record *subrec, struct packet_struct *p)
 441 {
 442         struct nmb_packet *nmb = &p->packet.nmb;
 443         struct nmb_name *question = &nmb->question.question_name;
 444         int name_type = question->name_type;
 445         bool bcast = nmb->header.nm_flags.bcast;
 446         int ttl=0;
 447         int rcode = 0;
 448         char *prdata = NULL;
 449         char rdata[6];
 450         bool success = False;
 451         struct name_record *namerec = NULL;
 452         int reply_data_len = 0;
 453         int i;
 454
 455         DEBUG(3,("process_name_query_request: Name query from %s on subnet %s for name %s\n",
 456                  inet_ntoa(p->ip), subrec->subnet_name, nmb_namestr(question)));
 457
 458         /* Look up the name in the cache - if the request is a broadcast request that
 459            came from a subnet we don't know about then search all the broadcast subnets
 460            for a match (as we don't know what interface the request came in on). */
 461
 462         if(subrec == remote_broadcast_subnet)
 463                 namerec = find_name_for_remote_broadcast_subnet( question, FIND_ANY_NAME);
 464         else
 465                 namerec = find_name_on_subnet(subrec, question, FIND_ANY_NAME);
 466
 467         /* Check if it is a name that expired */
 468         if (namerec &&
 469             ((namerec->data.death_time != PERMANENT_TTL) &&
 470              (namerec->data.death_time < p->timestamp))) {
 471                 DEBUG(5,("process_name_query_request: expired name %s\n", nmb_namestr(&namerec->name)));
 472                 namerec = NULL;
 473         }
 474
 475         if (namerec) {
 476                 /*
 477                  * Always respond to unicast queries.
 478                  * Don't respond to broadcast queries unless the query is for
 479                  * a name we own, a Primary Domain Controller name, or a WINS_PROXY
 480                  * name with type 0 or 0x20. WINS_PROXY names are only ever added
 481                  * into the namelist if we were configured as a WINS proxy.
 482                  */
 483
 484                 if (!bcast ||
 485                     (bcast && ((name_type == 0x1b) ||
 486                                (namerec->data.source == SELF_NAME) ||
 487                                (namerec->data.source == PERMANENT_NAME) ||
 488                                ((namerec->data.source == WINS_PROXY_NAME) &&
 489                                 ((name_type == 0) || (name_type == 0x20)))))) {
 490                         /* The requested name is a directed query, or it's SELF or PERMANENT or WINS_PROXY,
 491                            or it's a Domain Master type. */
 492
 493                         /*
 494                          * If this is a WINS_PROXY_NAME, then ceck that none of the IP
 495                          * addresses we are returning is on the same broadcast subnet
 496                          * as the requesting packet. If it is then don't reply as the
 497                          * actual machine will be replying also and we don't want two
 498                          * replies to a broadcast query.
 499                          */
 500
 501                         if (namerec->data.source == WINS_PROXY_NAME) {
 502                                 for( i = 0; i < namerec->data.num_ips; i++) {
 503                                         if (same_net_v4(namerec->data.ip[i], subrec->myip, subrec->mask_ip)) {
 504                                                 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",
 505                                                          nmb_namestr(&namerec->name), subrec->subnet_name ));
 506                                                 return;
 507                                         }
 508                                 }
 509                         }
 510
 511                         ttl = (namerec->data.death_time != PERMANENT_TTL) ?
 512                                 namerec->data.death_time - p->timestamp : lp_max_ttl();
 513
 514                         /* Copy all known ip addresses into the return data. */
 515                         /* Optimise for the common case of one IP address so
 516                            we don't need a malloc. */
 517
 518                         if (namerec->data.num_ips == 1) {
 519                                 prdata = rdata;
 520                         } else {
 521                                 if ((prdata = (char *)SMB_MALLOC( namerec->data.num_ips * 6 )) == NULL) {
 522                                         DEBUG(0,("process_name_query_request: malloc fail !\n"));
 523                                         return;
 524                                 }
 525                         }
 526
 527                         for (i = 0; i < namerec->data.num_ips; i++) {
 528                                 set_nb_flags(&prdata[i*6],namerec->data.nb_flags);
 529                                 putip((char *)&prdata[2+(i*6)], &namerec->data.ip[i]);
 530                         }
 531
 532                         sort_query_replies(prdata, i, p->ip);
 533
 534                         reply_data_len = namerec->data.num_ips * 6;
 535                         success = True;
 536                 }
 537         }
 538
 539         /*
 540          * If a machine is broadcasting a name lookup request and we have lp_wins_proxy()
 541          * set we should initiate a WINS query here. On success we add the resolved name
 542          * into our namelist with a type of WINS_PROXY_NAME and then reply to the query.
 543          */
 544
 545         if(!success && (namerec == NULL) && we_are_a_wins_client() && lp_wins_proxy() &&
 546            bcast && (subrec != remote_broadcast_subnet)) {
 547                 make_wins_proxy_name_query_request( subrec, p, question );
 548                 return;
 549         }
 550
 551         if (!success && bcast) {
 552                 if(prdata != rdata)
 553                         SAFE_FREE(prdata);
 554                 return; /* Never reply with a negative response to broadcasts. */
 555         }
 556
 557         /*
 558          * Final check. From observation, if a unicast packet is sent
 559          * to a non-WINS server with the recursion desired bit set
 560          * then never send a negative response.
 561          */
 562
 563         if(!success && !bcast && nmb->header.nm_flags.recursion_desired) {
 564                 if(prdata != rdata)
 565                         SAFE_FREE(prdata);
 566                 return;
 567         }
 568
 569         if (success) {
 570                 rcode = 0;
 571                 DEBUG(3,("OK\n"));
 572         } else {
 573                 rcode = NAM_ERR;
 574                 DEBUG(3,("UNKNOWN\n"));
 575         }
 576
 577         /* See rfc1002.txt 4.2.13. */
 578
 579         reply_netbios_packet(p,                              /* Packet to reply to. */
 580                              rcode,                          /* Result code. */
 581                              NMB_QUERY,                      /* nmbd type code. */
 582                              NMB_NAME_QUERY_OPCODE,          /* opcode. */
 583                              ttl,                            /* ttl. */
 584                              prdata,                         /* data to send. */
 585                              reply_data_len);                /* data length. */
 586
 587         if(prdata != rdata)
 588                 SAFE_FREE(prdata);
 589 }