source/kdc/kdc.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    KDC Server startup
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005
   7    Copyright (C) Andrew Tridgell        2005
   8    Copyright (C) Stefan Metzmacher      2005
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 2 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program; if not, write to the Free Software
  22    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  23 */
  24
  25 #include "includes.h"
  26 #include "smbd/service_task.h"
  27 #include "smbd/service.h"
  28 #include "smbd/service_stream.h"
  29 #include "smbd/process_model.h"
  30 #include "lib/events/events.h"
  31 #include "lib/socket/socket.h"
  32 #include "kdc/kdc.h"
  33 #include "system/network.h"
  34 #include "lib/util/dlinklist.h"
  35 #include "lib/messaging/irpc.h"
  36 #include "lib/stream/packet.h"
  37 #include "librpc/gen_ndr/samr.h"
  38 #include "lib/socket/netif.h"
  39
  40 /* hold all the info needed to send a reply */
  41 struct kdc_reply {
  42         struct kdc_reply *next, *prev;
  43         struct socket_address *dest;
  44         DATA_BLOB packet;
  45 };
  46
  47 typedef BOOL (*kdc_process_fn_t)(struct kdc_server *kdc,
  48                                  TALLOC_CTX *mem_ctx,
  49                                  DATA_BLOB *input,
  50                                  DATA_BLOB *reply,
  51                                  struct socket_address *peer_addr,
  52                                  struct socket_address *my_addr);
  53
  54 /* hold information about one kdc socket */
  55 struct kdc_socket {
  56         struct socket_context *sock;
  57         struct kdc_server *kdc;
  58         struct fd_event *fde;
  59
  60         /* a queue of outgoing replies that have been deferred */
  61         struct kdc_reply *send_queue;
  62
  63         kdc_process_fn_t process;
  64 };
  65 /*
  66   state of an open tcp connection
  67 */
  68 struct kdc_tcp_connection {
  69         /* stream connection we belong to */
  70         struct stream_connection *conn;
  71
  72         /* the kdc_server the connection belongs to */
  73         struct kdc_server *kdc;
  74
  75         struct packet_context *packet;
  76
  77         kdc_process_fn_t process;
  78 };
  79
  80 /*
  81   handle fd send events on a KDC socket
  82 */
  83 static void kdc_send_handler(struct kdc_socket *kdc_socket)
  84 {
  85         while (kdc_socket->send_queue) {
  86                 struct kdc_reply *rep = kdc_socket->send_queue;
  87                 NTSTATUS status;
  88                 size_t sendlen;
  89
  90                 status = socket_sendto(kdc_socket->sock, &rep->packet, &sendlen,
  91                                        rep->dest);
  92                 if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
  93                         break;
  94                 }
  95                 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_BUFFER_SIZE)) {
  96                         /* Replace with a krb err, response to big */
  97                 }
  98
  99                 DLIST_REMOVE(kdc_socket->send_queue, rep);
 100                 talloc_free(rep);
 101         }
 102
 103         if (kdc_socket->send_queue == NULL) {
 104                 EVENT_FD_NOT_WRITEABLE(kdc_socket->fde);
 105         }
 106 }
 107
 108
 109 /*
 110   handle fd recv events on a KDC socket
 111 */
 112 static void kdc_recv_handler(struct kdc_socket *kdc_socket)
 113 {
 114         NTSTATUS status;
 115         TALLOC_CTX *tmp_ctx = talloc_new(kdc_socket);
 116         DATA_BLOB blob;
 117         struct kdc_reply *rep;
 118         DATA_BLOB reply;
 119         size_t nread, dsize;
 120         struct socket_address *src;
 121         struct socket_address *my_addr;
 122         int ret;
 123
 124         status = socket_pending(kdc_socket->sock, &dsize);
 125         if (!NT_STATUS_IS_OK(status)) {
 126                 talloc_free(tmp_ctx);
 127                 return;
 128         }
 129
 130         blob = data_blob_talloc(tmp_ctx, NULL, dsize);
 131         if (blob.data == NULL) {
 132                 /* hope this is a temporary low memory condition */
 133                 talloc_free(tmp_ctx);
 134                 return;
 135         }
 136
 137         status = socket_recvfrom(kdc_socket->sock, blob.data, blob.length, &nread,
 138                                  tmp_ctx, &src);
 139         if (!NT_STATUS_IS_OK(status)) {
 140                 talloc_free(tmp_ctx);
 141                 return;
 142         }
 143         blob.length = nread;
 144
 145         DEBUG(10,("Received krb5 UDP packet of length %lu from %s:%u\n",
 146                  (long)blob.length, src->addr, (uint16_t)src->port));
 147
 148         my_addr = socket_get_my_addr(kdc_socket->sock, tmp_ctx);
 149         if (!my_addr) {
 150                 talloc_free(tmp_ctx);
 151                 return;
 152         }
 153
 154
 155         /* Call krb5 */
 156         ret = kdc_socket->process(kdc_socket->kdc,
 157                                   tmp_ctx,
 158                                   &blob,
 159                                   &reply,
 160                                   src, my_addr);
 161         if (!ret) {
 162                 talloc_free(tmp_ctx);
 163                 return;
 164         }
 165
 166         /* queue a pending reply */
 167         rep = talloc(kdc_socket, struct kdc_reply);
 168         if (rep == NULL) {
 169                 talloc_free(tmp_ctx);
 170                 return;
 171         }
 172         rep->dest         = talloc_steal(rep, src);
 173         rep->packet       = reply;
 174         talloc_steal(rep, reply.data);
 175
 176         if (rep->packet.data == NULL) {
 177                 talloc_free(rep);
 178                 talloc_free(tmp_ctx);
 179                 return;
 180         }
 181
 182         DLIST_ADD_END(kdc_socket->send_queue, rep, struct kdc_reply *);
 183         EVENT_FD_WRITEABLE(kdc_socket->fde);
 184         talloc_free(tmp_ctx);
 185 }
 186
 187 /*
 188   handle fd events on a KDC socket
 189 */
 190 static void kdc_socket_handler(struct event_context *ev, struct fd_event *fde,
 191                                uint16_t flags, void *private)
 192 {
 193         struct kdc_socket *kdc_socket = talloc_get_type(private, struct kdc_socket);
 194         if (flags & EVENT_FD_WRITE) {
 195                 kdc_send_handler(kdc_socket);
 196         }
 197         if (flags & EVENT_FD_READ) {
 198                 kdc_recv_handler(kdc_socket);
 199         }
 200 }
 201
 202 static void kdc_tcp_terminate_connection(struct kdc_tcp_connection *kdcconn, const char *reason)
 203 {
 204         stream_terminate_connection(kdcconn->conn, reason);
 205 }
 206
 207 /*
 208   receive a full packet on a KDC connection
 209 */
 210 static NTSTATUS kdc_tcp_recv(void *private, DATA_BLOB blob)
 211 {
 212         struct kdc_tcp_connection *kdcconn = talloc_get_type(private,
 213                                                              struct kdc_tcp_connection);
 214         NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
 215         TALLOC_CTX *tmp_ctx = talloc_new(kdcconn);
 216         int ret;
 217         DATA_BLOB input, reply;
 218         struct socket_address *src_addr;
 219         struct socket_address *my_addr;
 220
 221         talloc_steal(tmp_ctx, blob.data);
 222
 223         src_addr = socket_get_peer_addr(kdcconn->conn->socket, tmp_ctx);
 224         if (!src_addr) {
 225                 talloc_free(tmp_ctx);
 226                 return NT_STATUS_NO_MEMORY;
 227         }
 228
 229         my_addr = socket_get_my_addr(kdcconn->conn->socket, tmp_ctx);
 230         if (!my_addr) {
 231                 talloc_free(tmp_ctx);
 232                 return NT_STATUS_NO_MEMORY;
 233         }
 234
 235         /* Call krb5 */
 236         input = data_blob_const(blob.data + 4, blob.length - 4);
 237
 238         ret = kdcconn->process(kdcconn->kdc,
 239                                tmp_ctx,
 240                                &input,
 241                                &reply,
 242                                src_addr,
 243                                my_addr);
 244         if (!ret) {
 245                 talloc_free(tmp_ctx);
 246                 return NT_STATUS_INTERNAL_ERROR;
 247         }
 248
 249         /* and now encode the reply */
 250         blob = data_blob_talloc(kdcconn, NULL, reply.length + 4);
 251         if (!blob.data) {
 252                 talloc_free(tmp_ctx);
 253                 return NT_STATUS_NO_MEMORY;
 254         }
 255
 256         RSIVAL(blob.data, 0, reply.length);
 257         memcpy(blob.data + 4, reply.data, reply.length);
 258
 259         status = packet_send(kdcconn->packet, blob);
 260         if (!NT_STATUS_IS_OK(status)) {
 261                 talloc_free(tmp_ctx);
 262                 return status;
 263         }
 264
 265         /* the call isn't needed any more */
 266         talloc_free(tmp_ctx);
 267         return NT_STATUS_OK;
 268 }
 269
 270 /*
 271   receive some data on a KDC connection
 272 */
 273 static void kdc_tcp_recv_handler(struct stream_connection *conn, uint16_t flags)
 274 {
 275         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 276                                                              struct kdc_tcp_connection);
 277         packet_recv(kdcconn->packet);
 278 }
 279
 280 /*
 281   called on a tcp recv error
 282 */
 283 static void kdc_tcp_recv_error(void *private, NTSTATUS status)
 284 {
 285         struct kdc_tcp_connection *kdcconn = talloc_get_type(private, struct kdc_tcp_connection);
 286         kdc_tcp_terminate_connection(kdcconn, nt_errstr(status));
 287 }
 288
 289 /*
 290   called when we can write to a connection
 291 */
 292 static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
 293 {
 294         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 295                                                              struct kdc_tcp_connection);
 296         packet_queue_run(kdcconn->packet);
 297 }
 298
 299 /**
 300    Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
 301    calling conventions
 302 */
 303
 304 static BOOL kdc_process(struct kdc_server *kdc,
 305                         TALLOC_CTX *mem_ctx,
 306                         DATA_BLOB *input,
 307                         DATA_BLOB *reply,
 308                         struct socket_address *peer_addr,
 309                         struct socket_address *my_addr)
 310 {
 311         int ret;
 312         krb5_data k5_reply;
 313
 314         DEBUG(10,("Received KDC packet of length %lu from %s:%d\n",
 315                   (long)input->length - 4, peer_addr->addr, peer_addr->port));
 316
 317         ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
 318                                             kdc->config,
 319                                             input->data, input->length,
 320                                             &k5_reply,
 321                                             peer_addr->addr,
 322                                             peer_addr->sockaddr);
 323         if (ret == -1) {
 324                 *reply = data_blob(NULL, 0);
 325                 return False;
 326         }
 327         *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
 328         krb5_data_free(&k5_reply);
 329         return True;
 330 }
 331
 332 /*
 333   called when we get a new connection
 334 */
 335 static void kdc_tcp_generic_accept(struct stream_connection *conn, kdc_process_fn_t process_fn)
 336 {
 337         struct kdc_server *kdc = talloc_get_type(conn->private, struct kdc_server);
 338         struct kdc_tcp_connection *kdcconn;
 339
 340         kdcconn = talloc_zero(conn, struct kdc_tcp_connection);
 341         if (!kdcconn) {
 342                 stream_terminate_connection(conn, "kdc_tcp_accept: out of memory");
 343                 return;
 344         }
 345         kdcconn->conn    = conn;
 346         kdcconn->kdc     = kdc;
 347         kdcconn->process = process_fn;
 348         conn->private    = kdcconn;
 349
 350         kdcconn->packet = packet_init(kdcconn);
 351         if (kdcconn->packet == NULL) {
 352                 kdc_tcp_terminate_connection(kdcconn, "kdc_tcp_accept: out of memory");
 353                 return;
 354         }
 355         packet_set_private(kdcconn->packet, kdcconn);
 356         packet_set_socket(kdcconn->packet, conn->socket);
 357         packet_set_callback(kdcconn->packet, kdc_tcp_recv);
 358         packet_set_full_request(kdcconn->packet, packet_full_request_u32);
 359         packet_set_error_handler(kdcconn->packet, kdc_tcp_recv_error);
 360         packet_set_event_context(kdcconn->packet, conn->event.ctx);
 361         packet_set_fde(kdcconn->packet, conn->event.fde);
 362         packet_set_serialise(kdcconn->packet);
 363 }
 364
 365 static void kdc_tcp_accept(struct stream_connection *conn)
 366 {
 367         kdc_tcp_generic_accept(conn, kdc_process);
 368 }
 369
 370 static const struct stream_server_ops kdc_tcp_stream_ops = {
 371         .name                   = "kdc_tcp",
 372         .accept_connection      = kdc_tcp_accept,
 373         .recv_handler           = kdc_tcp_recv_handler,
 374         .send_handler           = kdc_tcp_send
 375 };
 376
 377 static void kpasswdd_tcp_accept(struct stream_connection *conn)
 378 {
 379         kdc_tcp_generic_accept(conn, kpasswdd_process);
 380 }
 381
 382 static const struct stream_server_ops kpasswdd_tcp_stream_ops = {
 383         .name                   = "kpasswdd_tcp",
 384         .accept_connection      = kpasswdd_tcp_accept,
 385         .recv_handler           = kdc_tcp_recv_handler,
 386         .send_handler           = kdc_tcp_send
 387 };
 388
 389 /*
 390   start listening on the given address
 391 */
 392 static NTSTATUS kdc_add_socket(struct kdc_server *kdc, const char *address)
 393 {
 394         const struct model_ops *model_ops;
 395         struct kdc_socket *kdc_socket;
 396         struct kdc_socket *kpasswd_socket;
 397         struct socket_address *kdc_address, *kpasswd_address;
 398         NTSTATUS status;
 399         uint16_t kdc_port = lp_krb5_port();
 400         uint16_t kpasswd_port = lp_kpasswd_port();
 401
 402         kdc_socket = talloc(kdc, struct kdc_socket);
 403         NT_STATUS_HAVE_NO_MEMORY(kdc_socket);
 404
 405         kpasswd_socket = talloc(kdc, struct kdc_socket);
 406         NT_STATUS_HAVE_NO_MEMORY(kpasswd_socket);
 407
 408         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kdc_socket->sock, 0);
 409         if (!NT_STATUS_IS_OK(status)) {
 410                 talloc_free(kdc_socket);
 411                 return status;
 412         }
 413
 414         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kpasswd_socket->sock, 0);
 415         if (!NT_STATUS_IS_OK(status)) {
 416                 talloc_free(kpasswd_socket);
 417                 return status;
 418         }
 419
 420         kdc_socket->kdc = kdc;
 421         kdc_socket->send_queue = NULL;
 422         kdc_socket->process = kdc_process;
 423
 424         talloc_steal(kdc_socket, kdc_socket->sock);
 425
 426         kdc_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 427                                        socket_get_fd(kdc_socket->sock), EVENT_FD_READ,
 428                                        kdc_socket_handler, kdc_socket);
 429
 430         kdc_address = socket_address_from_strings(kdc_socket, kdc_socket->sock->backend_name,
 431                                                   address, kdc_port);
 432         NT_STATUS_HAVE_NO_MEMORY(kdc_address);
 433
 434         status = socket_listen(kdc_socket->sock, kdc_address, 0, 0);
 435         if (!NT_STATUS_IS_OK(status)) {
 436                 DEBUG(0,("Failed to bind to %s:%d UDP for kdc - %s\n",
 437                          address, kdc_port, nt_errstr(status)));
 438                 talloc_free(kdc_socket);
 439                 return status;
 440         }
 441
 442         kpasswd_socket->kdc = kdc;
 443         kpasswd_socket->send_queue = NULL;
 444         kpasswd_socket->process = kpasswdd_process;
 445
 446         talloc_steal(kpasswd_socket, kpasswd_socket->sock);
 447
 448         kpasswd_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 449                                            socket_get_fd(kpasswd_socket->sock), EVENT_FD_READ,
 450                                            kdc_socket_handler, kpasswd_socket);
 451
 452         kpasswd_address = socket_address_from_strings(kpasswd_socket, kpasswd_socket->sock->backend_name,
 453                                                       address, kpasswd_port);
 454         NT_STATUS_HAVE_NO_MEMORY(kpasswd_address);
 455
 456         status = socket_listen(kpasswd_socket->sock, kpasswd_address, 0, 0);
 457         if (!NT_STATUS_IS_OK(status)) {
 458                 DEBUG(0,("Failed to bind to %s:%d UDP for kpasswd - %s\n",
 459                          address, kpasswd_port, nt_errstr(status)));
 460                 talloc_free(kpasswd_socket);
 461                 return status;
 462         }
 463
 464         /* within the kdc task we want to be a single process, so
 465            ask for the single process model ops and pass these to the
 466            stream_setup_socket() call. */
 467         model_ops = process_model_byname("single");
 468         if (!model_ops) {
 469                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 470                 talloc_free(kdc_socket);
 471                 return NT_STATUS_INTERNAL_ERROR;
 472         }
 473
 474         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 475                                      &kdc_tcp_stream_ops,
 476                                      "ip", address, &kdc_port, kdc);
 477         if (!NT_STATUS_IS_OK(status)) {
 478                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 479                          address, kdc_port, nt_errstr(status)));
 480                 talloc_free(kdc_socket);
 481                 return status;
 482         }
 483
 484         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 485                                      &kpasswdd_tcp_stream_ops,
 486                                      "ip", address, &kpasswd_port, kdc);
 487         if (!NT_STATUS_IS_OK(status)) {
 488                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 489                          address, kpasswd_port, nt_errstr(status)));
 490                 talloc_free(kdc_socket);
 491                 return status;
 492         }
 493
 494         return NT_STATUS_OK;
 495 }
 496
 497
 498 /*
 499   setup our listening sockets on the configured network interfaces
 500 */
 501 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc)
 502 {
 503         int num_interfaces = iface_count();
 504         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 505         NTSTATUS status;
 506
 507         int i;
 508
 509         for (i=0; i<num_interfaces; i++) {
 510                 const char *address = talloc_strdup(tmp_ctx, iface_n_ip(i));
 511                 status = kdc_add_socket(kdc, address);
 512                 NT_STATUS_NOT_OK_RETURN(status);
 513         }
 514
 515         talloc_free(tmp_ctx);
 516
 517         return NT_STATUS_OK;
 518 }
 519
 520 /*
 521   startup the kdc task
 522 */
 523 static void kdc_task_init(struct task_server *task)
 524 {
 525         struct kdc_server *kdc;
 526         NTSTATUS status;
 527         krb5_error_code ret;
 528
 529         switch (lp_server_role()) {
 530         case ROLE_STANDALONE:
 531                 task_server_terminate(task, "kdc: no KDC required in standalone configuration");
 532                 return;
 533         case ROLE_DOMAIN_MEMBER:
 534                 task_server_terminate(task, "kdc: no KDC required in member server configuration");
 535                 return;
 536         case ROLE_DOMAIN_PDC:
 537         case ROLE_DOMAIN_BDC:
 538                 /* Yes, we want a KDC */
 539                 break;
 540         }
 541
 542         if (iface_count() == 0) {
 543                 task_server_terminate(task, "kdc: no network interfaces configured");
 544                 return;
 545         }
 546
 547         task_server_set_title(task, "task[kdc]");
 548
 549         kdc = talloc(task, struct kdc_server);
 550         if (kdc == NULL) {
 551                 task_server_terminate(task, "kdc: out of memory");
 552                 return;
 553         }
 554
 555         kdc->task = task;
 556
 557         /* Setup the KDC configuration */
 558         kdc->config = talloc(kdc, krb5_kdc_configuration);
 559         if (!kdc->config) {
 560                 task_server_terminate(task, "kdc: out of memory");
 561                 return;
 562         }
 563         krb5_kdc_default_config(kdc->config);
 564
 565         initialize_krb5_error_table();
 566
 567         ret = smb_krb5_init_context(kdc, &kdc->smb_krb5_context);
 568         if (ret) {
 569                 DEBUG(1,("kdc_task_init: krb5_init_context failed (%s)\n",
 570                          error_message(ret)));
 571                 task_server_terminate(task, "kdc: krb5_init_context failed");
 572                 return;
 573         }
 574
 575         krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
 576
 577         kdc->config->logf = kdc->smb_krb5_context->logf;
 578         kdc->config->db = talloc(kdc->config, struct HDB *);
 579         if (!kdc->config->db) {
 580                 task_server_terminate(task, "kdc: out of memory");
 581                 return;
 582         }
 583         kdc->config->num_db = 1;
 584
 585         status = kdc_hdb_ldb_create(kdc, kdc->smb_krb5_context->krb5_context,
 586                                     &kdc->config->db[0], NULL);
 587         if (!NT_STATUS_IS_OK(status)) {
 588                 task_server_terminate(task, "kdc: hdb_ldb_create (setup KDC database) failed");
 589                 return;
 590         }
 591
 592         ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_kt_ops);
 593         if(ret) {
 594                 task_server_terminate(task, "kdc: failed to register hdb keytab");
 595                 return;
 596         }
 597         /* start listening on the configured network interfaces */
 598         status = kdc_startup_interfaces(kdc);
 599         if (!NT_STATUS_IS_OK(status)) {
 600                 task_server_terminate(task, "kdc failed to setup interfaces");
 601                 return;
 602         }
 603
 604         irpc_add_name(task->msg_ctx, "kdc_server");
 605 }
 606
 607
 608 /*
 609   called on startup of the KDC service
 610 */
 611 static NTSTATUS kdc_init(struct event_context *event_ctx,
 612                          const struct model_ops *model_ops)
 613 {
 614         return task_server_startup(event_ctx, model_ops, kdc_task_init);
 615 }
 616
 617 /* called at smbd startup - register ourselves as a server service */
 618 NTSTATUS server_service_kdc_init(void)
 619 {
 620         return register_server_service("kdc", kdc_init);
 621 }