source4/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_stream.h"
  28 #include "lib/events/events.h"
  29 #include "lib/socket/socket.h"
  30 #include "kdc/kdc.h"
  31 #include "system/network.h"
  32 #include "dlinklist.h"
  33 #include "lib/messaging/irpc.h"
  34 #include "lib/stream/packet.h"
  35
  36 #include "librpc/gen_ndr/samr.h"
  37
  38 /* hold all the info needed to send a reply */
  39 struct kdc_reply {
  40         struct kdc_reply *next, *prev;
  41         struct socket_address *dest;
  42         DATA_BLOB packet;
  43 };
  44
  45 typedef BOOL (*kdc_process_fn_t)(struct kdc_server *kdc,
  46                                  TALLOC_CTX *mem_ctx,
  47                                  DATA_BLOB *input,
  48                                  DATA_BLOB *reply,
  49                                  struct socket_address *peer_addr,
  50                                  struct socket_address *my_addr);
  51
  52 /* hold information about one kdc socket */
  53 struct kdc_socket {
  54         struct socket_context *sock;
  55         struct kdc_server *kdc;
  56         struct fd_event *fde;
  57
  58         /* a queue of outgoing replies that have been deferred */
  59         struct kdc_reply *send_queue;
  60
  61         kdc_process_fn_t process;
  62 };
  63 /*
  64   state of an open tcp connection
  65 */
  66 struct kdc_tcp_connection {
  67         /* stream connection we belong to */
  68         struct stream_connection *conn;
  69
  70         /* the kdc_server the connection belongs to */
  71         struct kdc_server *kdc;
  72
  73         struct packet_context *packet;
  74
  75         kdc_process_fn_t process;
  76 };
  77
  78 /*
  79   handle fd send events on a KDC socket
  80 */
  81 static void kdc_send_handler(struct kdc_socket *kdc_socket)
  82 {
  83         while (kdc_socket->send_queue) {
  84                 struct kdc_reply *rep = kdc_socket->send_queue;
  85                 NTSTATUS status;
  86                 size_t sendlen;
  87
  88                 status = socket_sendto(kdc_socket->sock, &rep->packet, &sendlen, 0,
  89                                        rep->dest);
  90                 if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
  91                         break;
  92                 }
  93                 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_BUFFER_SIZE)) {
  94                         /* Replace with a krb err, response to big */
  95                 }
  96
  97                 DLIST_REMOVE(kdc_socket->send_queue, rep);
  98                 talloc_free(rep);
  99         }
 100
 101         if (kdc_socket->send_queue == NULL) {
 102                 EVENT_FD_NOT_WRITEABLE(kdc_socket->fde);
 103         }
 104 }
 105
 106
 107 /*
 108   handle fd recv events on a KDC socket
 109 */
 110 static void kdc_recv_handler(struct kdc_socket *kdc_socket)
 111 {
 112         NTSTATUS status;
 113         TALLOC_CTX *tmp_ctx = talloc_new(kdc_socket);
 114         DATA_BLOB blob;
 115         struct kdc_reply *rep;
 116         DATA_BLOB reply;
 117         size_t nread, dsize;
 118         struct socket_address *src;
 119         struct socket_address *my_addr;
 120         int ret;
 121
 122         status = socket_pending(kdc_socket->sock, &dsize);
 123         if (!NT_STATUS_IS_OK(status)) {
 124                 talloc_free(tmp_ctx);
 125                 return;
 126         }
 127
 128         blob = data_blob_talloc(kdc_socket, NULL, dsize);
 129         if (blob.data == NULL) {
 130                 /* hope this is a temporary low memory condition */
 131                 talloc_free(tmp_ctx);
 132                 return;
 133         }
 134
 135         status = socket_recvfrom(kdc_socket->sock, blob.data, blob.length, &nread, 0,
 136                                  tmp_ctx, &src);
 137         if (!NT_STATUS_IS_OK(status)) {
 138                 talloc_free(tmp_ctx);
 139                 return;
 140         }
 141         blob.length = nread;
 142
 143         DEBUG(10,("Received krb5 UDP packet of length %lu from %s:%u\n",
 144                  (long)blob.length, src->addr, (uint16_t)src->port));
 145
 146         my_addr = socket_get_my_addr(kdc_socket->sock, tmp_ctx);
 147         if (!my_addr) {
 148                 talloc_free(tmp_ctx);
 149                 return;
 150         }
 151
 152
 153         /* Call krb5 */
 154         ret = kdc_socket->process(kdc_socket->kdc,
 155                                   tmp_ctx,
 156                                   &blob,
 157                                   &reply,
 158                                   src, my_addr);
 159         if (!ret) {
 160                 talloc_free(tmp_ctx);
 161                 return;
 162         }
 163
 164         /* queue a pending reply */
 165         rep = talloc(kdc_socket, struct kdc_reply);
 166         if (rep == NULL) {
 167                 talloc_free(tmp_ctx);
 168                 return;
 169         }
 170         rep->dest         = talloc_steal(rep, src);
 171         rep->packet       = reply;
 172         talloc_steal(rep, reply.data);
 173
 174         if (rep->packet.data == NULL) {
 175                 talloc_free(rep);
 176                 talloc_free(tmp_ctx);
 177                 return;
 178         }
 179
 180         DLIST_ADD_END(kdc_socket->send_queue, rep, struct kdc_reply *);
 181         EVENT_FD_WRITEABLE(kdc_socket->fde);
 182         talloc_free(tmp_ctx);
 183 }
 184
 185 /*
 186   handle fd events on a KDC socket
 187 */
 188 static void kdc_socket_handler(struct event_context *ev, struct fd_event *fde,
 189                                uint16_t flags, void *private)
 190 {
 191         struct kdc_socket *kdc_socket = talloc_get_type(private, struct kdc_socket);
 192         if (flags & EVENT_FD_WRITE) {
 193                 kdc_send_handler(kdc_socket);
 194         }
 195         if (flags & EVENT_FD_READ) {
 196                 kdc_recv_handler(kdc_socket);
 197         }
 198 }
 199
 200 static void kdc_tcp_terminate_connection(struct kdc_tcp_connection *kdcconn, const char *reason)
 201 {
 202         stream_terminate_connection(kdcconn->conn, reason);
 203 }
 204
 205 /*
 206   receive a full packet on a KDC connection
 207 */
 208 static NTSTATUS kdc_tcp_recv(void *private, DATA_BLOB blob)
 209 {
 210         struct kdc_tcp_connection *kdcconn = talloc_get_type(private,
 211                                                              struct kdc_tcp_connection);
 212         NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
 213         TALLOC_CTX *tmp_ctx = talloc_new(kdcconn);
 214         int ret;
 215         DATA_BLOB input, reply;
 216         struct socket_address *src_addr;
 217         struct socket_address *my_addr;
 218
 219         talloc_steal(tmp_ctx, blob.data);
 220
 221         src_addr = socket_get_peer_addr(kdcconn->conn->socket, tmp_ctx);
 222         if (!src_addr) {
 223                 talloc_free(tmp_ctx);
 224                 return NT_STATUS_NO_MEMORY;
 225         }
 226
 227         my_addr = socket_get_my_addr(kdcconn->conn->socket, tmp_ctx);
 228         if (!my_addr) {
 229                 talloc_free(tmp_ctx);
 230                 return NT_STATUS_NO_MEMORY;
 231         }
 232
 233         /* Call krb5 */
 234         input = data_blob_const(blob.data + 4, blob.length - 4);
 235
 236         ret = kdcconn->process(kdcconn->kdc,
 237                                tmp_ctx,
 238                                &input,
 239                                &reply,
 240                                src_addr,
 241                                my_addr);
 242         if (!ret) {
 243                 talloc_free(tmp_ctx);
 244                 return NT_STATUS_INTERNAL_ERROR;
 245         }
 246
 247         /* and now encode the reply */
 248         blob = data_blob_talloc(kdcconn, NULL, reply.length + 4);
 249         if (!blob.data) {
 250                 talloc_free(tmp_ctx);
 251                 return NT_STATUS_NO_MEMORY;
 252         }
 253
 254         RSIVAL(blob.data, 0, reply.length);
 255         memcpy(blob.data + 4, reply.data, reply.length);
 256
 257         status = packet_send(kdcconn->packet, blob);
 258         if (!NT_STATUS_IS_OK(status)) {
 259                 talloc_free(tmp_ctx);
 260                 return status;
 261         }
 262
 263         /* the call isn't needed any more */
 264         talloc_free(tmp_ctx);
 265         return NT_STATUS_OK;
 266 }
 267
 268 /*
 269   receive some data on a KDC connection
 270 */
 271 static void kdc_tcp_recv_handler(struct stream_connection *conn, uint16_t flags)
 272 {
 273         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 274                                                              struct kdc_tcp_connection);
 275         packet_recv(kdcconn->packet);
 276 }
 277
 278 /*
 279   called on a tcp recv error
 280 */
 281 static void kdc_tcp_recv_error(void *private, NTSTATUS status)
 282 {
 283         struct kdc_tcp_connection *kdcconn = talloc_get_type(private, struct kdc_tcp_connection);
 284         kdc_tcp_terminate_connection(kdcconn, nt_errstr(status));
 285 }
 286
 287 /*
 288   called when we can write to a connection
 289 */
 290 static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
 291 {
 292         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 293                                                              struct kdc_tcp_connection);
 294         packet_queue_run(kdcconn->packet);
 295 }
 296
 297 /**
 298    Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
 299    calling conventions
 300 */
 301
 302 static BOOL kdc_process(struct kdc_server *kdc,
 303                         TALLOC_CTX *mem_ctx,
 304                         DATA_BLOB *input,
 305                         DATA_BLOB *reply,
 306                         struct socket_address *peer_addr,
 307                         struct socket_address *my_addr)
 308 {
 309         int ret;
 310         krb5_data k5_reply;
 311
 312         DEBUG(10,("Received KDC packet of length %lu from %s:%d\n",
 313                   (long)input->length - 4, peer_addr->addr, peer_addr->port));
 314
 315         ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
 316                                             kdc->config,
 317                                             input->data, input->length,
 318                                             &k5_reply,
 319                                             peer_addr->addr,
 320                                             peer_addr->sockaddr);
 321         if (ret == -1) {
 322                 *reply = data_blob(NULL, 0);
 323                 return False;
 324         }
 325         *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
 326         krb5_data_free(&k5_reply);
 327         return True;
 328 }
 329
 330 /*
 331   called when we get a new connection
 332 */
 333 static void kdc_tcp_generic_accept(struct stream_connection *conn, kdc_process_fn_t process_fn)
 334 {
 335         struct kdc_server *kdc = talloc_get_type(conn->private, struct kdc_server);
 336         struct kdc_tcp_connection *kdcconn;
 337
 338         kdcconn = talloc_zero(conn, struct kdc_tcp_connection);
 339         if (!kdcconn) {
 340                 stream_terminate_connection(conn, "kdc_tcp_accept: out of memory");
 341                 return;
 342         }
 343         kdcconn->conn    = conn;
 344         kdcconn->kdc     = kdc;
 345         kdcconn->process = process_fn;
 346         conn->private    = kdcconn;
 347
 348         kdcconn->packet = packet_init(kdcconn);
 349         if (kdcconn->packet == NULL) {
 350                 kdc_tcp_terminate_connection(kdcconn, "kdc_tcp_accept: out of memory");
 351                 return;
 352         }
 353         packet_set_private(kdcconn->packet, kdcconn);
 354         packet_set_socket(kdcconn->packet, conn->socket);
 355         packet_set_callback(kdcconn->packet, kdc_tcp_recv);
 356         packet_set_full_request(kdcconn->packet, packet_full_request_u32);
 357         packet_set_error_handler(kdcconn->packet, kdc_tcp_recv_error);
 358         packet_set_event_context(kdcconn->packet, conn->event.ctx);
 359         packet_set_fde(kdcconn->packet, conn->event.fde);
 360         packet_set_serialise(kdcconn->packet);
 361 }
 362
 363 static void kdc_tcp_accept(struct stream_connection *conn)
 364 {
 365         kdc_tcp_generic_accept(conn, kdc_process);
 366 }
 367
 368 static const struct stream_server_ops kdc_tcp_stream_ops = {
 369         .name                   = "kdc_tcp",
 370         .accept_connection      = kdc_tcp_accept,
 371         .recv_handler           = kdc_tcp_recv_handler,
 372         .send_handler           = kdc_tcp_send
 373 };
 374
 375 static void kpasswdd_tcp_accept(struct stream_connection *conn)
 376 {
 377         kdc_tcp_generic_accept(conn, kpasswdd_process);
 378 }
 379
 380 static const struct stream_server_ops kpasswdd_tcp_stream_ops = {
 381         .name                   = "kpasswdd_tcp",
 382         .accept_connection      = kpasswdd_tcp_accept,
 383         .recv_handler           = kdc_tcp_recv_handler,
 384         .send_handler           = kdc_tcp_send
 385 };
 386
 387 /*
 388   start listening on the given address
 389 */
 390 static NTSTATUS kdc_add_socket(struct kdc_server *kdc, const char *address)
 391 {
 392         const struct model_ops *model_ops;
 393         struct kdc_socket *kdc_socket;
 394         struct kdc_socket *kpasswd_socket;
 395         struct socket_address *kdc_address, *kpasswd_address;
 396         NTSTATUS status;
 397         uint16_t kdc_port = lp_krb5_port();
 398         uint16_t kpasswd_port = lp_kpasswd_port();
 399
 400         kdc_socket = talloc(kdc, struct kdc_socket);
 401         NT_STATUS_HAVE_NO_MEMORY(kdc_socket);
 402
 403         kpasswd_socket = talloc(kdc, struct kdc_socket);
 404         NT_STATUS_HAVE_NO_MEMORY(kpasswd_socket);
 405
 406         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kdc_socket->sock, 0);
 407         if (!NT_STATUS_IS_OK(status)) {
 408                 talloc_free(kdc_socket);
 409                 return status;
 410         }
 411
 412         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kpasswd_socket->sock, 0);
 413         if (!NT_STATUS_IS_OK(status)) {
 414                 talloc_free(kpasswd_socket);
 415                 return status;
 416         }
 417
 418         kdc_socket->kdc = kdc;
 419         kdc_socket->send_queue = NULL;
 420         kdc_socket->process = kdc_process;
 421
 422         talloc_steal(kdc_socket, kdc_socket->sock);
 423
 424         kdc_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 425                                        socket_get_fd(kdc_socket->sock), EVENT_FD_READ,
 426                                        kdc_socket_handler, kdc_socket);
 427
 428         kdc_address = socket_address_from_strings(kdc_socket, kdc_socket->sock->backend_name,
 429                                                   address, kdc_port);
 430         NT_STATUS_HAVE_NO_MEMORY(kdc_address);
 431
 432         status = socket_listen(kdc_socket->sock, kdc_address, 0, 0);
 433         if (!NT_STATUS_IS_OK(status)) {
 434                 DEBUG(0,("Failed to bind to %s:%d UDP for kdc - %s\n",
 435                          address, kdc_port, nt_errstr(status)));
 436                 talloc_free(kdc_socket);
 437                 return status;
 438         }
 439
 440         kpasswd_socket->kdc = kdc;
 441         kpasswd_socket->send_queue = NULL;
 442         kpasswd_socket->process = kpasswdd_process;
 443
 444         talloc_steal(kpasswd_socket, kpasswd_socket->sock);
 445
 446         kpasswd_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 447                                            socket_get_fd(kpasswd_socket->sock), EVENT_FD_READ,
 448                                            kdc_socket_handler, kpasswd_socket);
 449
 450         kpasswd_address = socket_address_from_strings(kpasswd_socket, kpasswd_socket->sock->backend_name,
 451                                                       address, kpasswd_port);
 452         NT_STATUS_HAVE_NO_MEMORY(kpasswd_address);
 453
 454         status = socket_listen(kpasswd_socket->sock, kpasswd_address, 0, 0);
 455         if (!NT_STATUS_IS_OK(status)) {
 456                 DEBUG(0,("Failed to bind to %s:%d UDP for kpasswd - %s\n",
 457                          address, kpasswd_port, nt_errstr(status)));
 458                 talloc_free(kpasswd_socket);
 459                 return status;
 460         }
 461
 462         /* within the kdc task we want to be a single process, so
 463            ask for the single process model ops and pass these to the
 464            stream_setup_socket() call. */
 465         model_ops = process_model_byname("single");
 466         if (!model_ops) {
 467                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 468                 talloc_free(kdc_socket);
 469                 return NT_STATUS_INTERNAL_ERROR;
 470         }
 471
 472         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 473                                      &kdc_tcp_stream_ops,
 474                                      "ip", address, &kdc_port, kdc);
 475         if (!NT_STATUS_IS_OK(status)) {
 476                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 477                          address, kdc_port, nt_errstr(status)));
 478                 talloc_free(kdc_socket);
 479                 return status;
 480         }
 481
 482         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 483                                      &kpasswdd_tcp_stream_ops,
 484                                      "ip", address, &kpasswd_port, kdc);
 485         if (!NT_STATUS_IS_OK(status)) {
 486                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 487                          address, kpasswd_port, nt_errstr(status)));
 488                 talloc_free(kdc_socket);
 489                 return status;
 490         }
 491
 492         return NT_STATUS_OK;
 493 }
 494
 495
 496 /*
 497   setup our listening sockets on the configured network interfaces
 498 */
 499 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc)
 500 {
 501         int num_interfaces = iface_count();
 502         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 503         NTSTATUS status;
 504
 505         int i;
 506
 507         for (i=0; i<num_interfaces; i++) {
 508                 const char *address = talloc_strdup(tmp_ctx, iface_n_ip(i));
 509                 status = kdc_add_socket(kdc, address);
 510                 NT_STATUS_NOT_OK_RETURN(status);
 511         }
 512
 513         talloc_free(tmp_ctx);
 514
 515         return NT_STATUS_OK;
 516 }
 517
 518 /*
 519   startup the kdc task
 520 */
 521 static void kdc_task_init(struct task_server *task)
 522 {
 523         struct kdc_server *kdc;
 524         NTSTATUS status;
 525         krb5_error_code ret;
 526
 527         switch (lp_server_role()) {
 528         case ROLE_STANDALONE:
 529                 task_server_terminate(task, "kdc: no KDC required in standalone configuration");
 530                 return;
 531         case ROLE_DOMAIN_MEMBER:
 532                 task_server_terminate(task, "kdc: no KDC required in member server configuration");
 533                 return;
 534         case ROLE_DOMAIN_PDC:
 535         case ROLE_DOMAIN_BDC:
 536                 /* Yes, we want a KDC */
 537                 break;
 538         }
 539
 540         if (iface_count() == 0) {
 541                 task_server_terminate(task, "kdc: no network interfaces configured");
 542                 return;
 543         }
 544
 545         kdc = talloc(task, struct kdc_server);
 546         if (kdc == NULL) {
 547                 task_server_terminate(task, "kdc: out of memory");
 548                 return;
 549         }
 550
 551         kdc->task = task;
 552
 553         /* Setup the KDC configuration */
 554         kdc->config = talloc(kdc, krb5_kdc_configuration);
 555         if (!kdc->config) {
 556                 task_server_terminate(task, "kdc: out of memory");
 557                 return;
 558         }
 559         krb5_kdc_default_config(kdc->config);
 560
 561         initialize_krb5_error_table();
 562
 563         ret = smb_krb5_init_context(kdc, &kdc->smb_krb5_context);
 564         if (ret) {
 565                 DEBUG(1,("kdc_task_init: krb5_init_context failed (%s)\n",
 566                          error_message(ret)));
 567                 task_server_terminate(task, "kdc: krb5_init_context failed");
 568                 return;
 569         }
 570
 571         krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
 572
 573         kdc->config->logf = kdc->smb_krb5_context->logf;
 574         kdc->config->db = talloc(kdc->config, struct HDB *);
 575         if (!kdc->config->db) {
 576                 task_server_terminate(task, "kdc: out of memory");
 577                 return;
 578         }
 579         kdc->config->num_db = 1;
 580
 581         status = kdc_hdb_ldb_create(kdc, kdc->smb_krb5_context->krb5_context,
 582                                     &kdc->config->db[0], NULL);
 583         if (!NT_STATUS_IS_OK(status)) {
 584                 task_server_terminate(task, "kdc: hdb_ldb_create (setup KDC database) failed");
 585                 return;
 586         }
 587
 588         ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_kt_ops);
 589         if(ret) {
 590                 task_server_terminate(task, "kdc: failed to register hdb keytab");
 591                 return;
 592         }
 593         /* start listening on the configured network interfaces */
 594         status = kdc_startup_interfaces(kdc);
 595         if (!NT_STATUS_IS_OK(status)) {
 596                 task_server_terminate(task, "kdc failed to setup interfaces");
 597                 return;
 598         }
 599
 600         irpc_add_name(task->msg_ctx, "kdc_server");
 601 }
 602
 603
 604 /*
 605   called on startup of the KDC service
 606 */
 607 static NTSTATUS kdc_init(struct event_context *event_ctx,
 608                          const struct model_ops *model_ops)
 609 {
 610         return task_server_startup(event_ctx, model_ops, kdc_task_init);
 611 }
 612
 613 /* called at smbd startup - register ourselves as a server service */
 614 NTSTATUS server_service_kdc_init(void)
 615 {
 616         return register_server_service("kdc", kdc_init);
 617 }