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 /* hold all the info needed to send a reply */
  37 struct kdc_reply {
  38         struct kdc_reply *next, *prev;
  39         struct socket_address *dest;
  40         DATA_BLOB packet;
  41 };
  42
  43 typedef BOOL (*kdc_process_fn_t)(struct kdc_server *kdc,
  44                                  TALLOC_CTX *mem_ctx,
  45                                  DATA_BLOB *input,
  46                                  DATA_BLOB *reply,
  47                                  struct socket_address *peer_addr,
  48                                  struct socket_address *my_addr);
  49
  50 /* hold information about one kdc socket */
  51 struct kdc_socket {
  52         struct socket_context *sock;
  53         struct kdc_server *kdc;
  54         struct fd_event *fde;
  55
  56         /* a queue of outgoing replies that have been deferred */
  57         struct kdc_reply *send_queue;
  58
  59         kdc_process_fn_t process;
  60 };
  61 /*
  62   state of an open tcp connection
  63 */
  64 struct kdc_tcp_connection {
  65         /* stream connection we belong to */
  66         struct stream_connection *conn;
  67
  68         /* the kdc_server the connection belongs to */
  69         struct kdc_server *kdc;
  70
  71         struct packet_context *packet;
  72
  73         kdc_process_fn_t process;
  74 };
  75
  76 /*
  77   handle fd send events on a KDC socket
  78 */
  79 static void kdc_send_handler(struct kdc_socket *kdc_socket)
  80 {
  81         while (kdc_socket->send_queue) {
  82                 struct kdc_reply *rep = kdc_socket->send_queue;
  83                 NTSTATUS status;
  84                 size_t sendlen;
  85
  86                 status = socket_sendto(kdc_socket->sock, &rep->packet, &sendlen, 0,
  87                                        rep->dest);
  88                 if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
  89                         break;
  90                 }
  91                 if (NT_STATUS_EQUAL(status, NT_STATUS_INVALID_BUFFER_SIZE)) {
  92                         /* Replace with a krb err, response to big */
  93                 }
  94
  95                 DLIST_REMOVE(kdc_socket->send_queue, rep);
  96                 talloc_free(rep);
  97         }
  98
  99         if (kdc_socket->send_queue == NULL) {
 100                 EVENT_FD_NOT_WRITEABLE(kdc_socket->fde);
 101         }
 102 }
 103
 104
 105 /*
 106   handle fd recv events on a KDC socket
 107 */
 108 static void kdc_recv_handler(struct kdc_socket *kdc_socket)
 109 {
 110         NTSTATUS status;
 111         TALLOC_CTX *tmp_ctx = talloc_new(kdc_socket);
 112         DATA_BLOB blob;
 113         struct kdc_reply *rep;
 114         DATA_BLOB reply;
 115         size_t nread, dsize;
 116         struct socket_address *src;
 117         struct socket_address *my_addr;
 118         int ret;
 119
 120         status = socket_pending(kdc_socket->sock, &dsize);
 121         if (!NT_STATUS_IS_OK(status)) {
 122                 talloc_free(tmp_ctx);
 123                 return;
 124         }
 125
 126         blob = data_blob_talloc(kdc_socket, NULL, dsize);
 127         if (blob.data == NULL) {
 128                 /* hope this is a temporary low memory condition */
 129                 talloc_free(tmp_ctx);
 130                 return;
 131         }
 132
 133         status = socket_recvfrom(kdc_socket->sock, blob.data, blob.length, &nread, 0,
 134                                  tmp_ctx, &src);
 135         if (!NT_STATUS_IS_OK(status)) {
 136                 talloc_free(tmp_ctx);
 137                 return;
 138         }
 139         blob.length = nread;
 140
 141         DEBUG(10,("Received krb5 UDP packet of length %lu from %s:%u\n",
 142                  (long)blob.length, src->addr, (uint16_t)src->port));
 143
 144         my_addr = socket_get_my_addr(kdc_socket->sock, tmp_ctx);
 145         if (!my_addr) {
 146                 talloc_free(tmp_ctx);
 147                 return;
 148         }
 149
 150
 151         /* Call krb5 */
 152         ret = kdc_socket->process(kdc_socket->kdc,
 153                                   tmp_ctx,
 154                                   &blob,
 155                                   &reply,
 156                                   src, my_addr);
 157         if (!ret) {
 158                 talloc_free(tmp_ctx);
 159                 return;
 160         }
 161
 162         /* queue a pending reply */
 163         rep = talloc(kdc_socket, struct kdc_reply);
 164         if (rep == NULL) {
 165                 talloc_free(tmp_ctx);
 166                 return;
 167         }
 168         rep->dest         = talloc_steal(rep, src);
 169         rep->packet       = reply;
 170         talloc_steal(rep, reply.data);
 171
 172         if (rep->packet.data == NULL) {
 173                 talloc_free(rep);
 174                 talloc_free(tmp_ctx);
 175                 return;
 176         }
 177
 178         DLIST_ADD_END(kdc_socket->send_queue, rep, struct kdc_reply *);
 179         EVENT_FD_WRITEABLE(kdc_socket->fde);
 180         talloc_free(tmp_ctx);
 181 }
 182
 183 /*
 184   handle fd events on a KDC socket
 185 */
 186 static void kdc_socket_handler(struct event_context *ev, struct fd_event *fde,
 187                                uint16_t flags, void *private)
 188 {
 189         struct kdc_socket *kdc_socket = talloc_get_type(private, struct kdc_socket);
 190         if (flags & EVENT_FD_WRITE) {
 191                 kdc_send_handler(kdc_socket);
 192         }
 193         if (flags & EVENT_FD_READ) {
 194                 kdc_recv_handler(kdc_socket);
 195         }
 196 }
 197
 198 static void kdc_tcp_terminate_connection(struct kdc_tcp_connection *kdcconn, const char *reason)
 199 {
 200         stream_terminate_connection(kdcconn->conn, reason);
 201 }
 202
 203 /*
 204   receive a full packet on a KDC connection
 205 */
 206 static NTSTATUS kdc_tcp_recv(void *private, DATA_BLOB blob)
 207 {
 208         struct kdc_tcp_connection *kdcconn = talloc_get_type(private,
 209                                                              struct kdc_tcp_connection);
 210         NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
 211         TALLOC_CTX *tmp_ctx = talloc_new(kdcconn);
 212         int ret;
 213         DATA_BLOB input, reply;
 214         struct socket_address *src_addr;
 215         struct socket_address *my_addr;
 216
 217         talloc_steal(tmp_ctx, blob.data);
 218
 219         src_addr = socket_get_peer_addr(kdcconn->conn->socket, tmp_ctx);
 220         if (!src_addr) {
 221                 talloc_free(tmp_ctx);
 222                 return NT_STATUS_NO_MEMORY;
 223         }
 224
 225         my_addr = socket_get_my_addr(kdcconn->conn->socket, tmp_ctx);
 226         if (!my_addr) {
 227                 talloc_free(tmp_ctx);
 228                 return NT_STATUS_NO_MEMORY;
 229         }
 230
 231         /* Call krb5 */
 232         input = data_blob_const(blob.data + 4, blob.length - 4);
 233
 234         ret = kdcconn->process(kdcconn->kdc,
 235                                tmp_ctx,
 236                                &input,
 237                                &reply,
 238                                src_addr,
 239                                my_addr);
 240         if (!ret) {
 241                 talloc_free(tmp_ctx);
 242                 return NT_STATUS_INTERNAL_ERROR;
 243         }
 244
 245         /* and now encode the reply */
 246         blob = data_blob_talloc(kdcconn, NULL, reply.length + 4);
 247         if (!blob.data) {
 248                 talloc_free(tmp_ctx);
 249                 return NT_STATUS_NO_MEMORY;
 250         }
 251
 252         RSIVAL(blob.data, 0, reply.length);
 253         memcpy(blob.data + 4, reply.data, reply.length);
 254
 255         status = packet_send(kdcconn->packet, blob);
 256         if (!NT_STATUS_IS_OK(status)) {
 257                 talloc_free(tmp_ctx);
 258                 return status;
 259         }
 260
 261         /* the call isn't needed any more */
 262         talloc_free(tmp_ctx);
 263         return NT_STATUS_OK;
 264 }
 265
 266 /*
 267   receive some data on a KDC connection
 268 */
 269 static void kdc_tcp_recv_handler(struct stream_connection *conn, uint16_t flags)
 270 {
 271         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 272                                                              struct kdc_tcp_connection);
 273         packet_recv(kdcconn->packet);
 274 }
 275
 276 /*
 277   called on a tcp recv error
 278 */
 279 static void kdc_tcp_recv_error(void *private, NTSTATUS status)
 280 {
 281         struct kdc_tcp_connection *kdcconn = talloc_get_type(private, struct kdc_tcp_connection);
 282         kdc_tcp_terminate_connection(kdcconn, nt_errstr(status));
 283 }
 284
 285 /*
 286   called when we can write to a connection
 287 */
 288 static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
 289 {
 290         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 291                                                              struct kdc_tcp_connection);
 292         packet_queue_run(kdcconn->packet);
 293 }
 294
 295 /**
 296    Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
 297    calling conventions
 298 */
 299
 300 static BOOL kdc_process(struct kdc_server *kdc,
 301                         TALLOC_CTX *mem_ctx,
 302                         DATA_BLOB *input,
 303                         DATA_BLOB *reply,
 304                         struct socket_address *peer_addr,
 305                         struct socket_address *my_addr)
 306 {
 307         int ret;
 308         krb5_data k5_reply;
 309
 310         DEBUG(10,("Received KDC packet of length %lu from %s:%d\n",
 311                   (long)input->length - 4, peer_addr->addr, peer_addr->port));
 312
 313         ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
 314                                             kdc->config,
 315                                             input->data, input->length,
 316                                             &k5_reply,
 317                                             peer_addr->addr,
 318                                             peer_addr->sockaddr);
 319         if (ret == -1) {
 320                 *reply = data_blob(NULL, 0);
 321                 return False;
 322         }
 323         *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
 324         krb5_data_free(&k5_reply);
 325         return True;
 326 }
 327
 328 /*
 329   called when we get a new connection
 330 */
 331 static void kdc_tcp_generic_accept(struct stream_connection *conn, kdc_process_fn_t process_fn)
 332 {
 333         struct kdc_server *kdc = talloc_get_type(conn->private, struct kdc_server);
 334         struct kdc_tcp_connection *kdcconn;
 335
 336         kdcconn = talloc_zero(conn, struct kdc_tcp_connection);
 337         if (!kdcconn) {
 338                 stream_terminate_connection(conn, "kdc_tcp_accept: out of memory");
 339                 return;
 340         }
 341         kdcconn->conn    = conn;
 342         kdcconn->kdc     = kdc;
 343         kdcconn->process = process_fn;
 344         conn->private    = kdcconn;
 345
 346         kdcconn->packet = packet_init(kdcconn);
 347         if (kdcconn->packet == NULL) {
 348                 kdc_tcp_terminate_connection(kdcconn, "kdc_tcp_accept: out of memory");
 349                 return;
 350         }
 351         packet_set_private(kdcconn->packet, kdcconn);
 352         packet_set_socket(kdcconn->packet, conn->socket);
 353         packet_set_callback(kdcconn->packet, kdc_tcp_recv);
 354         packet_set_full_request(kdcconn->packet, packet_full_request_u32);
 355         packet_set_error_handler(kdcconn->packet, kdc_tcp_recv_error);
 356         packet_set_event_context(kdcconn->packet, conn->event.ctx);
 357         packet_set_fde(kdcconn->packet, conn->event.fde);
 358         packet_set_serialise(kdcconn->packet);
 359 }
 360
 361 static void kdc_tcp_accept(struct stream_connection *conn)
 362 {
 363         kdc_tcp_generic_accept(conn, kdc_process);
 364 }
 365
 366 static const struct stream_server_ops kdc_tcp_stream_ops = {
 367         .name                   = "kdc_tcp",
 368         .accept_connection      = kdc_tcp_accept,
 369         .recv_handler           = kdc_tcp_recv_handler,
 370         .send_handler           = kdc_tcp_send
 371 };
 372
 373 static void kpasswdd_tcp_accept(struct stream_connection *conn)
 374 {
 375         kdc_tcp_generic_accept(conn, kpasswdd_process);
 376 }
 377
 378 static const struct stream_server_ops kpasswdd_tcp_stream_ops = {
 379         .name                   = "kpasswdd_tcp",
 380         .accept_connection      = kpasswdd_tcp_accept,
 381         .recv_handler           = kdc_tcp_recv_handler,
 382         .send_handler           = kdc_tcp_send
 383 };
 384
 385 /*
 386   start listening on the given address
 387 */
 388 static NTSTATUS kdc_add_socket(struct kdc_server *kdc, const char *address)
 389 {
 390         const struct model_ops *model_ops;
 391         struct kdc_socket *kdc_socket;
 392         struct kdc_socket *kpasswd_socket;
 393         struct socket_address *kdc_address, *kpasswd_address;
 394         NTSTATUS status;
 395         uint16_t kdc_port = lp_krb5_port();
 396         uint16_t kpasswd_port = lp_kpasswd_port();
 397
 398         kdc_socket = talloc(kdc, struct kdc_socket);
 399         NT_STATUS_HAVE_NO_MEMORY(kdc_socket);
 400
 401         kpasswd_socket = talloc(kdc, struct kdc_socket);
 402         NT_STATUS_HAVE_NO_MEMORY(kpasswd_socket);
 403
 404         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kdc_socket->sock, 0);
 405         if (!NT_STATUS_IS_OK(status)) {
 406                 talloc_free(kdc_socket);
 407                 return status;
 408         }
 409
 410         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kpasswd_socket->sock, 0);
 411         if (!NT_STATUS_IS_OK(status)) {
 412                 talloc_free(kpasswd_socket);
 413                 return status;
 414         }
 415
 416         kdc_socket->kdc = kdc;
 417         kdc_socket->send_queue = NULL;
 418         kdc_socket->process = kdc_process;
 419
 420         talloc_steal(kdc_socket, kdc_socket->sock);
 421
 422         kdc_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 423                                        socket_get_fd(kdc_socket->sock), EVENT_FD_READ,
 424                                        kdc_socket_handler, kdc_socket);
 425
 426         kdc_address = socket_address_from_strings(kdc_socket, kdc_socket->sock->backend_name,
 427                                                   address, kdc_port);
 428         NT_STATUS_HAVE_NO_MEMORY(kdc_address);
 429
 430         status = socket_listen(kdc_socket->sock, kdc_address, 0, 0);
 431         if (!NT_STATUS_IS_OK(status)) {
 432                 DEBUG(0,("Failed to bind to %s:%d UDP for kdc - %s\n",
 433                          address, kdc_port, nt_errstr(status)));
 434                 talloc_free(kdc_socket);
 435                 return status;
 436         }
 437
 438         kpasswd_socket->kdc = kdc;
 439         kpasswd_socket->send_queue = NULL;
 440         kpasswd_socket->process = kpasswdd_process;
 441
 442         talloc_steal(kpasswd_socket, kpasswd_socket->sock);
 443
 444         kpasswd_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 445                                            socket_get_fd(kpasswd_socket->sock), EVENT_FD_READ,
 446                                            kdc_socket_handler, kpasswd_socket);
 447
 448         kpasswd_address = socket_address_from_strings(kpasswd_socket, kpasswd_socket->sock->backend_name,
 449                                                       address, kpasswd_port);
 450         NT_STATUS_HAVE_NO_MEMORY(kpasswd_address);
 451
 452         status = socket_listen(kpasswd_socket->sock, kpasswd_address, 0, 0);
 453         if (!NT_STATUS_IS_OK(status)) {
 454                 DEBUG(0,("Failed to bind to %s:%d UDP for kpasswd - %s\n",
 455                          address, kpasswd_port, nt_errstr(status)));
 456                 talloc_free(kpasswd_socket);
 457                 return status;
 458         }
 459
 460         /* within the kdc task we want to be a single process, so
 461            ask for the single process model ops and pass these to the
 462            stream_setup_socket() call. */
 463         model_ops = process_model_byname("single");
 464         if (!model_ops) {
 465                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 466                 talloc_free(kdc_socket);
 467                 return NT_STATUS_INTERNAL_ERROR;
 468         }
 469
 470         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 471                                      &kdc_tcp_stream_ops,
 472                                      "ip", address, &kdc_port, kdc);
 473         if (!NT_STATUS_IS_OK(status)) {
 474                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 475                          address, kdc_port, nt_errstr(status)));
 476                 talloc_free(kdc_socket);
 477                 return status;
 478         }
 479
 480         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 481                                      &kpasswdd_tcp_stream_ops,
 482                                      "ip", address, &kpasswd_port, kdc);
 483         if (!NT_STATUS_IS_OK(status)) {
 484                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 485                          address, kpasswd_port, nt_errstr(status)));
 486                 talloc_free(kdc_socket);
 487                 return status;
 488         }
 489
 490         return NT_STATUS_OK;
 491 }
 492
 493
 494 /*
 495   setup our listening sockets on the configured network interfaces
 496 */
 497 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc)
 498 {
 499         int num_interfaces = iface_count();
 500         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 501         NTSTATUS status;
 502
 503         /* if we are allowing incoming packets from any address, then
 504            we need to bind to the wildcard address */
 505         if (!lp_bind_interfaces_only()) {
 506                 status = kdc_add_socket(kdc, "0.0.0.0");
 507                 NT_STATUS_NOT_OK_RETURN(status);
 508         } else {
 509                 int i;
 510
 511                 for (i=0; i<num_interfaces; i++) {
 512                         const char *address = talloc_strdup(tmp_ctx, iface_n_ip(i));
 513                         status = kdc_add_socket(kdc, address);
 514                         NT_STATUS_NOT_OK_RETURN(status);
 515                 }
 516         }
 517
 518         talloc_free(tmp_ctx);
 519
 520         return NT_STATUS_OK;
 521 }
 522
 523 /*
 524   startup the kdc task
 525 */
 526 static void kdc_task_init(struct task_server *task)
 527 {
 528         struct kdc_server *kdc;
 529         NTSTATUS status;
 530         krb5_error_code ret;
 531
 532         if (iface_count() == 0) {
 533                 task_server_terminate(task, "kdc: no network interfaces configured");
 534                 return;
 535         }
 536
 537         kdc = talloc(task, struct kdc_server);
 538         if (kdc == NULL) {
 539                 task_server_terminate(task, "kdc: out of memory");
 540                 return;
 541         }
 542
 543         kdc->task = task;
 544
 545         /* Setup the KDC configuration */
 546         kdc->config = talloc(kdc, krb5_kdc_configuration);
 547         if (!kdc->config) {
 548                 task_server_terminate(task, "kdc: out of memory");
 549                 return;
 550         }
 551         krb5_kdc_default_config(kdc->config);
 552
 553         initialize_krb5_error_table();
 554
 555         ret = smb_krb5_init_context(kdc, &kdc->smb_krb5_context);
 556         if (ret) {
 557                 DEBUG(1,("kdc_task_init: krb5_init_context failed (%s)\n",
 558                          error_message(ret)));
 559                 task_server_terminate(task, "kdc: krb5_init_context failed");
 560                 return;
 561         }
 562
 563         krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
 564
 565         kdc->config->logf = kdc->smb_krb5_context->logf;
 566         kdc->config->db = talloc(kdc->config, struct HDB *);
 567         if (!kdc->config->db) {
 568                 task_server_terminate(task, "kdc: out of memory");
 569                 return;
 570         }
 571         kdc->config->num_db = 1;
 572
 573         status = hdb_ldb_create(kdc, kdc->smb_krb5_context->krb5_context,
 574                                    &kdc->config->db[0], NULL);
 575         if (!NT_STATUS_IS_OK(status)) {
 576                 task_server_terminate(task, "kdc: hdb_ldb_create (setup KDC database) failed");
 577                 return;
 578         }
 579
 580         /* start listening on the configured network interfaces */
 581         status = kdc_startup_interfaces(kdc);
 582         if (!NT_STATUS_IS_OK(status)) {
 583                 task_server_terminate(task, "kdc failed to setup interfaces");
 584                 return;
 585         }
 586
 587         irpc_add_name(task->msg_ctx, "kdc_server");
 588 }
 589
 590
 591 /*
 592   called on startup of the KDC service
 593 */
 594 static NTSTATUS kdc_init(struct event_context *event_ctx,
 595                          const struct model_ops *model_ops)
 596 {
 597         return task_server_startup(event_ctx, model_ops, kdc_task_init);
 598 }
 599
 600 /* called at smbd startup - register ourselves as a server service */
 601 NTSTATUS server_service_kdc_init(void)
 602 {
 603         return register_server_service("kdc", kdc_init);
 604 }