source3/nsswitch/winbindd_ldap.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    winbind ldap proxy code
   5
   6    Copyright (C) Volker Lendecke
   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
  23 #include "includes.h"
  24 #include "winbindd.h"
  25
  26 /* This rw-buf api is made to avoid memcpy. For now do that like mad...  The
  27    idea is to write into a circular list of buffers where the ideal case is
  28    that a read(2) holds a complete request that is then thrown away
  29    completely. */
  30
  31 struct ldap_message_queue {
  32         struct ldap_message_queue *prev, *next;
  33         struct ldap_message *msg;
  34 };
  35
  36 struct rw_buffer {
  37         uint8 *data;
  38         size_t ofs, length;
  39 };
  40
  41 struct winbind_ldap_client {
  42         struct winbind_ldap_client *next, *prev;
  43         int sock;
  44         BOOL finished;
  45         struct rw_buffer in_buffer, out_buffer;
  46 };
  47
  48 static struct winbind_ldap_client *ldap_clients;
  49
  50 struct winbind_ldap_server {
  51         struct winbind_ldap_server *next, *prev;
  52         int sock;
  53         BOOL ready;             /* Bind successful? */
  54         BOOL finished;
  55         struct rw_buffer in_buffer, out_buffer;
  56         int messageid;
  57 };
  58
  59 static struct winbind_ldap_server *ldap_servers;
  60
  61 struct pending_ldap_message {
  62         struct pending_ldap_message *next, *prev;
  63         struct ldap_message *msg; /* The message the client sent us */
  64         int our_msgid;          /* The messageid we used */
  65         struct winbind_ldap_client *client;
  66 };
  67
  68 struct pending_ldap_message *pending_messages;
  69
  70 static BOOL append_to_buf(struct rw_buffer *buf, uint8 *data, size_t length)
  71 {
  72         buf->data = SMB_REALLOC(buf->data, buf->length+length);
  73
  74         if (buf->data == NULL)
  75                 return False;
  76
  77         memcpy(buf->data+buf->length, data, length);
  78
  79         buf->length += length;
  80         return True;
  81 }
  82
  83 static BOOL read_into_buf(int fd, struct rw_buffer *buf)
  84 {
  85         char tmp_buf[1024];
  86         int len;
  87
  88         len = read(fd, tmp_buf, sizeof(tmp_buf));
  89         if (len == 0)
  90                 return False;
  91
  92         return append_to_buf(buf, tmp_buf, len);
  93 }
  94
  95 static void peek_into_buf(struct rw_buffer *buf, uint8 **out,
  96                           size_t *out_length)
  97 {
  98         *out = buf->data;
  99         *out_length = buf->length;
 100 }
 101
 102 static void consumed_from_buf(struct rw_buffer *buf, size_t length)
 103 {
 104         uint8 *new = memdup(buf->data+length, buf->length-length);
 105         free(buf->data);
 106         buf->data = new;
 107         buf->length -= length;
 108 }
 109
 110 static BOOL write_out_of_buf(int fd, struct rw_buffer *buf)
 111 {
 112         uint8 *tmp;
 113         size_t tmp_length, written;
 114
 115         peek_into_buf(buf, &tmp, &tmp_length);
 116         if (tmp_length == 0)
 117                 return True;
 118
 119         written = write(fd, tmp, tmp_length);
 120         if (written < 0)
 121                 return False;
 122
 123         consumed_from_buf(buf, written);
 124         return True;
 125 }
 126
 127 static BOOL ldap_append_to_buf(struct ldap_message *msg, struct rw_buffer *buf)
 128 {
 129         DATA_BLOB blob;
 130         BOOL res;
 131
 132         if (!ldap_encode(msg, &blob))
 133                 return False;
 134
 135         res = append_to_buf(buf, blob.data, blob.length);
 136
 137         data_blob_free(&blob);
 138         return res;
 139 }
 140
 141 static void new_ldap_client(int listen_sock)
 142 {
 143         struct sockaddr_un sunaddr;
 144         struct winbind_ldap_client *client;
 145         socklen_t len;
 146         int sock;
 147
 148         /* Accept connection */
 149
 150         len = sizeof(sunaddr);
 151
 152         do {
 153                 sock = accept(listen_sock, (struct sockaddr *)&sunaddr, &len);
 154         } while (sock == -1 && errno == EINTR);
 155
 156         if (sock == -1)
 157                 return;
 158
 159         DEBUG(6,("accepted socket %d\n", sock));
 160
 161         /* Create new connection structure */
 162
 163         client = SMB_MALLOC_P(struct winbind_ldap_client);
 164
 165         if (client == NULL)
 166                 return;
 167
 168         ZERO_STRUCTP(client);
 169
 170         client->sock = sock;
 171         client->finished = False;
 172
 173         DLIST_ADD(ldap_clients, client);
 174 }
 175
 176 static struct ldap_message *get_msg_from_buf(struct rw_buffer *buffer,
 177                                              BOOL *error)
 178 {
 179         uint8 *buf;
 180         int buf_length, msg_length;
 181         DATA_BLOB blob;
 182         ASN1_DATA data;
 183         struct ldap_message *msg;
 184
 185         DEBUG(10,("ldapsrv_recv\n"));
 186
 187         *error = False;
 188
 189         peek_into_buf(buffer, &buf, &buf_length);
 190
 191         if (buf_length < 8) {
 192                 /* Arbitrary heuristics: ldap messages are longer than eight
 193                  * bytes, and their tag length fits into the eight bytes */
 194                 return NULL;
 195         }
 196
 197         /* LDAP Messages are always SEQUENCES */
 198
 199         if (!asn1_object_length(buf, buf_length, ASN1_SEQUENCE(0),
 200                                 &msg_length))
 201                 goto disconnect;
 202
 203         if (buf_length < msg_length) {
 204                 /* Not enough yet */
 205                 return NULL;
 206         }
 207
 208         /* We've got a complete LDAP request in the in-buffer */
 209
 210         blob.data = buf;
 211         blob.length = msg_length;
 212
 213         if (!asn1_load(&data, blob))
 214                 goto disconnect;
 215
 216         msg = new_ldap_message();
 217
 218         if ((msg == NULL) || !ldap_decode(&data, msg)) {
 219                 asn1_free(&data);
 220                 goto disconnect;
 221         }
 222
 223         asn1_free(&data);
 224
 225         consumed_from_buf(buffer, msg_length);
 226
 227         return msg;
 228
 229  disconnect:
 230
 231         *error = True;
 232         return NULL;
 233 }
 234
 235 static int send_msg_to_server(struct ldap_message *msg,
 236                               struct winbind_ldap_server *server)
 237 {
 238         int cli_messageid;
 239
 240         cli_messageid = msg->messageid;
 241         msg->messageid = ldap_servers->messageid;
 242
 243         if (!ldap_append_to_buf(msg, &ldap_servers->out_buffer))
 244                 return -1;
 245
 246         msg->messageid = cli_messageid;
 247         return ldap_servers->messageid++;
 248 }
 249
 250 static int send_msg(struct ldap_message *msg)
 251 {
 252         /* This is the scheduling routine that should decide where to send
 253          * stuff. The first attempt is easy: We only have one server. This
 254          * will change once we handle referrals etc. */
 255
 256         SMB_ASSERT(ldap_servers != NULL);
 257
 258         if (!ldap_servers->ready)
 259                 return -1;
 260
 261         return send_msg_to_server(msg, ldap_servers);
 262 }
 263
 264 static void fake_bind_response(struct winbind_ldap_client *client,
 265                                int messageid)
 266 {
 267         struct ldap_message *msg = new_ldap_message();
 268
 269         if (msg == NULL) {
 270                 client->finished = True;
 271                 return;
 272         }
 273
 274         msg->messageid = messageid;
 275         msg->type = LDAP_TAG_BindResponse;
 276         msg->r.BindResponse.response.resultcode = 0;
 277         msg->r.BindResponse.response.dn = "";
 278         msg->r.BindResponse.response.dn = "";
 279         msg->r.BindResponse.response.errormessage = "";
 280         msg->r.BindResponse.response.referral = "";
 281         ldap_append_to_buf(msg, &client->out_buffer);
 282         destroy_ldap_message(msg);
 283 }
 284
 285 static int open_ldap_socket(void)
 286 {
 287         static int fd = -1;
 288
 289         if (fd >= 0)
 290                 return fd;
 291
 292         fd = create_pipe_sock(get_winbind_priv_pipe_dir(), "ldapi", 0750);
 293         return fd;
 294 }
 295
 296 static BOOL do_sigterm = False;
 297
 298 static void ldap_termination_handler(int signum)
 299 {
 300         do_sigterm = True;
 301         sys_select_signal();
 302 }
 303
 304 static BOOL handled_locally(struct ldap_message *msg,
 305                             struct winbind_ldap_server *server)
 306 {
 307         struct ldap_Result *r = &msg->r.BindResponse.response;
 308
 309         if (msg->type != LDAP_TAG_BindResponse)
 310                 return False;
 311
 312         if (r->resultcode != 0) {
 313                 destroy_ldap_message(msg);
 314                 server->finished = True;
 315         }
 316         destroy_ldap_message(msg);
 317         server->ready = True;
 318         return True;
 319 }
 320
 321 static void client_has_data(struct winbind_ldap_client *client)
 322 {
 323
 324         struct ldap_message *msg;
 325
 326         if (!read_into_buf(client->sock, &client->in_buffer)) {
 327                 client->finished = True;
 328                 return;
 329         }
 330
 331         while ((msg = get_msg_from_buf(&client->in_buffer,
 332                                        &client->finished))) {
 333                 struct pending_ldap_message *pending;
 334
 335                 if (msg->type == LDAP_TAG_BindRequest) {
 336                         fake_bind_response(client, msg->messageid);
 337                         destroy_ldap_message(msg);
 338                         continue;
 339                 }
 340
 341                 if (msg->type == LDAP_TAG_UnbindRequest) {
 342                         destroy_ldap_message(msg);
 343                         client->finished = True;
 344                         break;
 345                 }
 346
 347                 pending = SMB_MALLOC_P(struct pending_ldap_message);
 348                 if (pending == NULL)
 349                         continue;
 350
 351                 pending->msg = msg;
 352                 pending->client = client;
 353                 pending->our_msgid = send_msg(msg);
 354
 355                 if (pending->our_msgid < 0) {
 356                         /* could not send */
 357                         client->finished = True;
 358                         free(pending);
 359                 }
 360                 DLIST_ADD(pending_messages, pending);
 361         }
 362 }
 363
 364 static struct ldap_Result *ldap_msg2result(struct ldap_message *msg)
 365 {
 366         switch(msg->type) {
 367         case LDAP_TAG_BindResponse:
 368                 return &msg->r.BindResponse.response;
 369         case LDAP_TAG_SearchResultDone:
 370                 return &msg->r.SearchResultDone;
 371         case LDAP_TAG_ModifyResponse:
 372                 return &msg->r.ModifyResponse;
 373         case LDAP_TAG_AddResponse:
 374                 return &msg->r.AddResponse;
 375         case LDAP_TAG_DelResponse:
 376                 return &msg->r.DelResponse;
 377         case LDAP_TAG_ModifyDNResponse:
 378                 return &msg->r.ModifyDNResponse;
 379         case LDAP_TAG_CompareResponse:
 380                 return &msg->r.CompareResponse;
 381         case LDAP_TAG_ExtendedResponse:
 382                 return &msg->r.ExtendedResponse.response;
 383         }
 384         return NULL;
 385 }
 386
 387 static void server_has_data(struct winbind_ldap_server *server)
 388 {
 389         struct ldap_message *msg;
 390
 391         if (!read_into_buf(server->sock, &server->in_buffer)) {
 392                 server->finished = True;
 393                 return;
 394         }
 395
 396         while ((msg = get_msg_from_buf(&server->in_buffer,
 397                                        &server->finished))) {
 398                 struct pending_ldap_message *pending;
 399                 struct rw_buffer *buf;
 400                 struct ldap_Result *res;
 401
 402                 if (handled_locally(msg, server))
 403                         continue;
 404
 405                 res = ldap_msg2result(msg);
 406
 407                 if ( (res != NULL) && (res->resultcode == 10) )
 408                         DEBUG(5, ("Got Referral %s\n", res->referral));
 409
 410                 for (pending = pending_messages;
 411                      pending != NULL;
 412                      pending = pending->next) {
 413                         if (pending->our_msgid == msg->messageid)
 414                                 break;
 415                 }
 416
 417                 if (pending == NULL) {
 418                         talloc_destroy(msg->mem_ctx);
 419                         continue;
 420                 }
 421
 422                 msg->messageid = pending->msg->messageid;
 423
 424                 buf = &pending->client->out_buffer;
 425                 ldap_append_to_buf(msg, buf);
 426
 427                 if ( (msg->type != LDAP_TAG_SearchResultEntry) &&
 428                      (msg->type != LDAP_TAG_SearchResultReference) ) {
 429                         destroy_ldap_message(pending->msg);
 430                         DLIST_REMOVE(pending_messages,
 431                                      pending);
 432                         SAFE_FREE(pending);
 433                 }
 434                 destroy_ldap_message(msg);
 435         }
 436 }
 437
 438 static void process_ldap_loop(void)
 439 {
 440         struct winbind_ldap_client *client;
 441         struct winbind_ldap_server *server;
 442         fd_set r_fds, w_fds;
 443         int maxfd, listen_sock, selret;
 444         struct timeval timeout;
 445
 446         /* Free up temporary memory */
 447
 448         lp_TALLOC_FREE();
 449         main_loop_TALLOC_FREE();
 450
 451         if (do_sigterm) {
 452 #if 0
 453                 TALLOC_CTX *mem_ctx = talloc_init("describe");
 454                 DEBUG(0, ("%s\n", talloc_describe_all(mem_ctx)));
 455                 talloc_destroy(mem_ctx);
 456 #endif
 457                 exit(0);
 458         }
 459
 460         /* Initialise fd lists for select() */
 461
 462         listen_sock = open_ldap_socket();
 463
 464         if (listen_sock == -1) {
 465                 perror("open_ldap_socket");
 466                 exit(1);
 467         }
 468
 469         maxfd = listen_sock;
 470
 471         FD_ZERO(&r_fds);
 472         FD_ZERO(&w_fds);
 473         FD_SET(listen_sock, &r_fds);
 474
 475         timeout.tv_sec = WINBINDD_ESTABLISH_LOOP;
 476         timeout.tv_usec = 0;
 477
 478         /* Set up client readers and writers */
 479
 480         client = ldap_clients;
 481
 482         while (client != NULL) {
 483
 484                 if (client->finished) {
 485                         struct winbind_ldap_client *next = client->next;
 486                         DLIST_REMOVE(ldap_clients, client);
 487                         close(client->sock);
 488                         SAFE_FREE(client->in_buffer.data);
 489                         SAFE_FREE(client->out_buffer.data);
 490                         SAFE_FREE(client);
 491                         client = next;
 492                         continue;
 493                 }
 494
 495                 if (client->sock > maxfd)
 496                         maxfd = client->sock;
 497
 498                 FD_SET(client->sock, &r_fds);
 499
 500                 if (client->out_buffer.length > 0)
 501                         FD_SET(client->sock, &w_fds);
 502
 503                 client = client->next;
 504         }
 505
 506         /* And now the servers */
 507
 508         server = ldap_servers;
 509
 510         while (server != NULL) {
 511
 512                 if (server->finished) {
 513                         struct winbind_ldap_server *next = server->next;
 514                         DLIST_REMOVE(ldap_servers, server);
 515                         close(server->sock);
 516                         SAFE_FREE(server);
 517                         server = next;
 518                         continue;
 519                 }
 520
 521                 if (server->sock > maxfd)
 522                         maxfd = server->sock;
 523
 524                 FD_SET(server->sock, &r_fds);
 525
 526                 if (server->out_buffer.length > 0)
 527                         FD_SET(server->sock, &w_fds);
 528
 529                 server = server->next;
 530         }
 531
 532         selret = sys_select(maxfd + 1, &r_fds, &w_fds, NULL, &timeout);
 533
 534         if (selret == 0)
 535                 return;
 536
 537         if (selret == -1 && errno != EINTR) {
 538                 perror("select");
 539                 exit(1);
 540         }
 541
 542         if (FD_ISSET(listen_sock, &r_fds))
 543                 new_ldap_client(listen_sock);
 544
 545         for (client = ldap_clients; client != NULL; client = client->next) {
 546
 547                 if (FD_ISSET(client->sock, &r_fds))
 548                         client_has_data(client);
 549
 550                 if ((!client->finished) && FD_ISSET(client->sock, &w_fds))
 551                         write_out_of_buf(client->sock, &client->out_buffer);
 552         }
 553
 554         for (server = ldap_servers; server != NULL; server = server->next) {
 555
 556                 if (FD_ISSET(server->sock, &r_fds))
 557                         server_has_data(server);
 558
 559                 if (!server->finished && FD_ISSET(server->sock, &w_fds))
 560                         write_out_of_buf(server->sock, &server->out_buffer);
 561         }
 562 }
 563
 564 static BOOL setup_ldap_serverconn(void)
 565 {
 566         char *host;
 567         uint16 port;
 568         BOOL ldaps;
 569         struct hostent *hp;
 570         struct in_addr ip;
 571         TALLOC_CTX *mem_ctx = talloc_init("server");
 572         struct ldap_message *msg;
 573         char *dn, *pw;
 574
 575         ldap_servers = SMB_MALLOC_P(struct winbind_ldap_server);
 576
 577         if ((ldap_servers == NULL) || (mem_ctx == NULL))
 578                 return False;
 579
 580         if (!ldap_parse_basic_url(mem_ctx, "ldap://192.168.234.1:3899/",
 581                                   &host, &port, &ldaps))
 582                 return False;
 583
 584         hp = sys_gethostbyname(host);
 585
 586         if ((hp == NULL) || (hp->h_addr == NULL))
 587                 return False;
 588
 589         putip((char *)&ip, (char *)hp->h_addr);
 590
 591         ZERO_STRUCTP(ldap_servers);
 592         ldap_servers->sock = open_socket_out(SOCK_STREAM, &ip, port, 10000);
 593         ldap_servers->messageid = 1;
 594
 595         if (!fetch_ldap_pw(&dn, &pw))
 596                 return False;
 597
 598         msg = new_ldap_simple_bind_msg(dn, pw);
 599
 600         SAFE_FREE(dn);
 601         SAFE_FREE(pw);
 602
 603         if (msg == NULL)
 604                 return False;
 605
 606         msg->messageid = ldap_servers->messageid++;
 607
 608         ldap_append_to_buf(msg, &ldap_servers->out_buffer);
 609
 610         destroy_ldap_message(msg);
 611
 612         return (ldap_servers->sock >= 0);
 613 }
 614
 615 void do_ldap_proxy(void)
 616 {
 617         int ldap_child;
 618
 619         ldap_child = sys_fork();
 620
 621         if (ldap_child != 0)
 622                 return;
 623
 624         /* tdb needs special fork handling */
 625         if (tdb_reopen_all() == -1) {
 626                 DEBUG(0,("tdb_reopen_all failed.\n"));
 627                 _exit(0);
 628         }
 629
 630         if (!message_init()) {
 631                 DEBUG(0, ("message_init failed\n"));
 632                 _exit(0);
 633         }
 634
 635         CatchSignal(SIGINT, ldap_termination_handler);
 636         CatchSignal(SIGQUIT, ldap_termination_handler);
 637         CatchSignal(SIGTERM, ldap_termination_handler);
 638
 639         if (!setup_ldap_serverconn())
 640                 return;
 641
 642         while (1)
 643                 process_ldap_loop();
 644
 645         return;
 646 }