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_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         const char *dest_address;
  40         int dest_port;
  41         DATA_BLOB packet;
  42 };
  43
  44 /* hold information about one kdc socket */
  45 struct kdc_socket {
  46         struct socket_context *sock;
  47         struct kdc_server *kdc;
  48         struct fd_event *fde;
  49
  50         /* a queue of outgoing replies that have been deferred */
  51         struct kdc_reply *send_queue;
  52
  53         BOOL (*process)(struct kdc_server *kdc,
  54                         TALLOC_CTX *mem_ctx,
  55                         DATA_BLOB *input,
  56                         DATA_BLOB *reply,
  57                         const char *from,
  58                         int src_port);
  59 };
  60 /*
  61   state of an open tcp connection
  62 */
  63 struct kdc_tcp_connection {
  64         /* stream connection we belong to */
  65         struct stream_connection *conn;
  66
  67         /* the kdc_server the connection belongs to */
  68         struct kdc_server *kdc;
  69
  70         struct packet_context *packet;
  71
  72         BOOL (*process)(struct kdc_server *kdc,
  73                          TALLOC_CTX *mem_ctx,
  74                          DATA_BLOB *input,
  75                          DATA_BLOB *reply,
  76                          const char *from,
  77                          int src_port);
  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, 0,
  91                                        rep->dest_address, rep->dest_port);
  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         const char *src_addr;
 121         int src_port;
 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(kdc_socket, 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, 0,
 138                                  &src_addr, &src_port);
 139         if (!NT_STATUS_IS_OK(status)) {
 140                 talloc_free(tmp_ctx);
 141                 return;
 142         }
 143         talloc_steal(tmp_ctx, src_addr);
 144         blob.length = nread;
 145
 146         DEBUG(2,("Received krb5 UDP packet of length %u from %s:%u\n",
 147                  blob.length, src_addr, (uint16_t)src_port));
 148
 149         /* Call krb5 */
 150         ret = kdc_socket->process(kdc_socket->kdc,
 151                                   tmp_ctx,
 152                                   &blob,
 153                                   &reply,
 154                                   src_addr, src_port);
 155         if (!ret) {
 156                 talloc_free(tmp_ctx);
 157                 return;
 158         }
 159
 160         /* queue a pending reply */
 161         rep = talloc(kdc_socket, struct kdc_reply);
 162         if (rep == NULL) {
 163                 talloc_free(tmp_ctx);
 164                 return;
 165         }
 166         rep->dest_address = talloc_steal(rep, src_addr);
 167         rep->dest_port    = src_port;
 168         rep->packet       = reply;
 169         talloc_steal(rep, reply.data);
 170
 171         if (rep->packet.data == NULL) {
 172                 talloc_free(rep);
 173                 talloc_free(tmp_ctx);
 174                 return;
 175         }
 176
 177         DLIST_ADD_END(kdc_socket->send_queue, rep, struct kdc_reply *);
 178         EVENT_FD_WRITEABLE(kdc_socket->fde);
 179         talloc_free(tmp_ctx);
 180 }
 181
 182 /*
 183   handle fd events on a KDC socket
 184 */
 185 static void kdc_socket_handler(struct event_context *ev, struct fd_event *fde,
 186                                uint16_t flags, void *private)
 187 {
 188         struct kdc_socket *kdc_socket = talloc_get_type(private, struct kdc_socket);
 189         if (flags & EVENT_FD_WRITE) {
 190                 kdc_send_handler(kdc_socket);
 191         }
 192         if (flags & EVENT_FD_READ) {
 193                 kdc_recv_handler(kdc_socket);
 194         }
 195 }
 196
 197 static void kdc_tcp_terminate_connection(struct kdc_tcp_connection *kdcconn, const char *reason)
 198 {
 199         stream_terminate_connection(kdcconn->conn, reason);
 200 }
 201
 202 /*
 203   receive a full packet on a KDC connection
 204 */
 205 static NTSTATUS kdc_tcp_recv(void *private, DATA_BLOB blob)
 206 {
 207         struct kdc_tcp_connection *kdcconn = talloc_get_type(private,
 208                                                              struct kdc_tcp_connection);
 209         NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
 210         TALLOC_CTX *tmp_ctx = talloc_new(kdcconn);
 211         const char *src_addr;
 212         int src_port;
 213         int ret;
 214         DATA_BLOB input, reply;
 215
 216         talloc_steal(tmp_ctx, blob.data);
 217
 218         src_addr = socket_get_peer_addr(kdcconn->conn->socket, tmp_ctx);
 219         if (!src_addr) goto nomem;
 220         src_port = socket_get_peer_port(kdcconn->conn->socket);
 221
 222         DEBUG(2,("Received krb5 TCP packet of length %u from %s:%u\n",
 223                  blob.length - 4, src_addr, src_port));
 224
 225         /* Call krb5 */
 226         input = data_blob_const(blob.data + 4, blob.length - 4);
 227
 228         ret = kdcconn->process(kdcconn->kdc,
 229                                tmp_ctx,
 230                                &input,
 231                                &reply,
 232                                src_addr, src_port);
 233         if (!ret) {
 234                 status = NT_STATUS_INTERNAL_ERROR;
 235                 goto failed;
 236         }
 237
 238         /* and now encode the reply */
 239         blob = data_blob_talloc(kdcconn, NULL, reply.length + 4);
 240         if (!blob.data) {
 241                 goto nomem;
 242         }
 243
 244         RSIVAL(blob.data, 0, reply.length);
 245         memcpy(blob.data + 4, reply.data, reply.length);
 246
 247         status = packet_send(kdcconn->packet, blob);
 248         if (!NT_STATUS_IS_OK(status)) {
 249                 goto failed;
 250         }
 251
 252         /* the call isn't needed any more */
 253         talloc_free(tmp_ctx);
 254         return NT_STATUS_OK;
 255 nomem:
 256         status = NT_STATUS_NO_MEMORY;
 257
 258 failed:
 259         return status;
 260 }
 261
 262 /*
 263   receive some data on a KDC connection
 264 */
 265 static void kdc_tcp_recv_handler(struct stream_connection *conn, uint16_t flags)
 266 {
 267         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 268                                                              struct kdc_tcp_connection);
 269         packet_recv(kdcconn->packet);
 270 }
 271
 272 /*
 273   called on a tcp recv error
 274 */
 275 static void kdc_tcp_recv_error(void *private, NTSTATUS status)
 276 {
 277         struct kdc_tcp_connection *kdcconn = talloc_get_type(private, struct kdc_tcp_connection);
 278         kdc_tcp_terminate_connection(kdcconn, nt_errstr(status));
 279 }
 280
 281 /*
 282   called when we can write to a connection
 283 */
 284 static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
 285 {
 286         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private,
 287                                                              struct kdc_tcp_connection);
 288         packet_queue_run(kdcconn->packet);
 289 }
 290
 291 /**
 292    Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
 293    calling conventions
 294 */
 295
 296 static BOOL kdc_process(struct kdc_server *kdc,
 297                         TALLOC_CTX *mem_ctx,
 298                         DATA_BLOB *input,
 299                         DATA_BLOB *reply,
 300                         const char *src_addr,
 301                         int src_port)
 302 {
 303         int ret;
 304         krb5_data k5_reply;
 305         struct ipv4_addr addr;
 306         struct sockaddr_in src_sock_addr;
 307
 308         /* TODO:  This really should be in a utility function somewhere */
 309         ZERO_STRUCT(src_sock_addr);
 310 #ifdef HAVE_SOCK_SIN_LEN
 311         src_sock_addr.sin_len           = sizeof(src_sock_addr);
 312 #endif
 313         addr                            = interpret_addr2(src_addr);
 314         src_sock_addr.sin_addr.s_addr   = addr.addr;
 315         src_sock_addr.sin_port          = htons(src_port);
 316         src_sock_addr.sin_family        = PF_INET;
 317
 318
 319         ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
 320                                             kdc->config,
 321                                             input->data, input->length,
 322                                             &k5_reply,
 323                                             src_addr,
 324                                             (struct sockaddr *)&src_sock_addr);
 325         if (ret == -1) {
 326                 *reply = data_blob(NULL, 0);
 327                 return False;
 328         }
 329         *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
 330         krb5_data_free(&k5_reply);
 331         return True;
 332 }
 333
 334 /*
 335   called when we get a new connection
 336 */
 337 static void kdc_tcp_accept(struct stream_connection *conn)
 338 {
 339         struct kdc_server *kdc = talloc_get_type(conn->private, struct kdc_server);
 340         struct kdc_tcp_connection *kdcconn;
 341
 342         kdcconn = talloc_zero(conn, struct kdc_tcp_connection);
 343         if (!kdcconn) {
 344                 stream_terminate_connection(conn, "kdc_tcp_accept: out of memory");
 345                 return;
 346         }
 347         kdcconn->conn    = conn;
 348         kdcconn->kdc     = kdc;
 349         kdcconn->process = kdc_process;
 350         conn->private    = kdcconn;
 351
 352         kdcconn->packet = packet_init(kdcconn);
 353         if (kdcconn->packet == NULL) {
 354                 stream_terminate_connection(conn, "kdc_tcp_accept: out of memory");
 355                 return;
 356         }
 357         packet_set_private(kdcconn->packet, kdcconn);
 358         packet_set_socket(kdcconn->packet, conn->socket);
 359         packet_set_callback(kdcconn->packet, kdc_tcp_recv);
 360         packet_set_full_request(kdcconn->packet, packet_full_request_u32);
 361         packet_set_error_handler(kdcconn->packet, kdc_tcp_recv_error);
 362         packet_set_event_context(kdcconn->packet, conn->event.ctx);
 363         packet_set_serialise(kdcconn->packet, conn->event.fde);
 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 /*
 374   called when we get a new connection
 375 */
 376 void kpasswdd_tcp_accept(struct stream_connection *conn)
 377 {
 378         struct kdc_server *kdc = talloc_get_type(conn->private, struct kdc_server);
 379         struct kdc_tcp_connection *kdcconn;
 380
 381         kdcconn = talloc_zero(conn, struct kdc_tcp_connection);
 382         if (!kdcconn) {
 383                 stream_terminate_connection(conn, "kdc_tcp_accept: out of memory");
 384                 return;
 385         }
 386         kdcconn->conn    = conn;
 387         kdcconn->kdc     = kdc;
 388         kdcconn->process = kpasswdd_process;
 389         conn->private    = kdcconn;
 390 }
 391
 392 static const struct stream_server_ops kpasswdd_tcp_stream_ops = {
 393         .name                   = "kpasswdd_tcp",
 394         .accept_connection      = kpasswdd_tcp_accept,
 395         .recv_handler           = kdc_tcp_recv_handler,
 396         .send_handler           = kdc_tcp_send
 397 };
 398
 399 /*
 400   start listening on the given address
 401 */
 402 static NTSTATUS kdc_add_socket(struct kdc_server *kdc, const char *address)
 403 {
 404         const struct model_ops *model_ops;
 405         struct kdc_socket *kdc_socket;
 406         struct kdc_socket *kpasswd_socket;
 407         NTSTATUS status;
 408         uint16_t kdc_port = lp_krb5_port();
 409         uint16_t kpasswd_port = lp_kpasswd_port();
 410
 411         kdc_socket = talloc(kdc, struct kdc_socket);
 412         NT_STATUS_HAVE_NO_MEMORY(kdc_socket);
 413
 414         kpasswd_socket = talloc(kdc, struct kdc_socket);
 415         NT_STATUS_HAVE_NO_MEMORY(kpasswd_socket);
 416
 417         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kdc_socket->sock, 0);
 418         if (!NT_STATUS_IS_OK(status)) {
 419                 talloc_free(kdc_socket);
 420                 return status;
 421         }
 422
 423         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kpasswd_socket->sock, 0);
 424         if (!NT_STATUS_IS_OK(status)) {
 425                 talloc_free(kpasswd_socket);
 426                 return status;
 427         }
 428
 429         kdc_socket->kdc = kdc;
 430         kdc_socket->send_queue = NULL;
 431         kdc_socket->process = kdc_process;
 432
 433         talloc_steal(kdc_socket, kdc_socket->sock);
 434
 435         kdc_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 436                                        socket_get_fd(kdc_socket->sock), EVENT_FD_READ,
 437                                        kdc_socket_handler, kdc_socket);
 438
 439         status = socket_listen(kdc_socket->sock, address, kdc_port, 0, 0);
 440         if (!NT_STATUS_IS_OK(status)) {
 441                 DEBUG(0,("Failed to bind to %s:%d UDP for kdc - %s\n",
 442                          address, kdc_port, nt_errstr(status)));
 443                 talloc_free(kdc_socket);
 444                 return status;
 445         }
 446
 447         kpasswd_socket->kdc = kdc;
 448         kpasswd_socket->send_queue = NULL;
 449         kpasswd_socket->process = kpasswdd_process;
 450
 451         talloc_steal(kpasswd_socket, kpasswd_socket->sock);
 452
 453         kpasswd_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 454                                            socket_get_fd(kpasswd_socket->sock), EVENT_FD_READ,
 455                                            kdc_socket_handler, kpasswd_socket);
 456
 457         status = socket_listen(kpasswd_socket->sock, address, kpasswd_port, 0, 0);
 458         if (!NT_STATUS_IS_OK(status)) {
 459                 DEBUG(0,("Failed to bind to %s:%d UDP for kpasswd - %s\n",
 460                          address, kpasswd_port, nt_errstr(status)));
 461                 talloc_free(kpasswd_socket);
 462                 return status;
 463         }
 464
 465         /* within the kdc task we want to be a single process, so
 466            ask for the single process model ops and pass these to the
 467            stream_setup_socket() call. */
 468         model_ops = process_model_byname("single");
 469         if (!model_ops) {
 470                 DEBUG(0,("Can't find 'single' process model_ops\n"));
 471                 talloc_free(kdc_socket);
 472                 return NT_STATUS_INTERNAL_ERROR;
 473         }
 474
 475         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 476                                      &kdc_tcp_stream_ops,
 477                                      "ip", address, &kdc_port, kdc);
 478         if (!NT_STATUS_IS_OK(status)) {
 479                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 480                          address, kdc_port, nt_errstr(status)));
 481                 talloc_free(kdc_socket);
 482                 return status;
 483         }
 484
 485         status = stream_setup_socket(kdc->task->event_ctx, model_ops,
 486                                      &kpasswdd_tcp_stream_ops,
 487                                      "ip", address, &kpasswd_port, kdc);
 488         if (!NT_STATUS_IS_OK(status)) {
 489                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 490                          address, kpasswd_port, nt_errstr(status)));
 491                 talloc_free(kdc_socket);
 492                 return status;
 493         }
 494
 495         return NT_STATUS_OK;
 496 }
 497
 498
 499 /*
 500   setup our listening sockets on the configured network interfaces
 501 */
 502 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc)
 503 {
 504         int num_interfaces = iface_count();
 505         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 506         NTSTATUS status;
 507
 508         /* if we are allowing incoming packets from any address, then
 509            we need to bind to the wildcard address */
 510         if (!lp_bind_interfaces_only()) {
 511                 status = kdc_add_socket(kdc, "0.0.0.0");
 512                 NT_STATUS_NOT_OK_RETURN(status);
 513         } else {
 514                 int i;
 515
 516                 for (i=0; i<num_interfaces; i++) {
 517                         const char *address = talloc_strdup(tmp_ctx, iface_n_ip(i));
 518                         status = kdc_add_socket(kdc, address);
 519                         NT_STATUS_NOT_OK_RETURN(status);
 520                 }
 521         }
 522
 523         talloc_free(tmp_ctx);
 524
 525         return NT_STATUS_OK;
 526 }
 527
 528 /*
 529   startup the kdc task
 530 */
 531 static void kdc_task_init(struct task_server *task)
 532 {
 533         struct kdc_server *kdc;
 534         NTSTATUS status;
 535         krb5_error_code ret;
 536
 537         if (iface_count() == 0) {
 538                 task_server_terminate(task, "kdc: no network interfaces configured");
 539                 return;
 540         }
 541
 542         kdc = talloc(task, struct kdc_server);
 543         if (kdc == NULL) {
 544                 task_server_terminate(task, "kdc: out of memory");
 545                 return;
 546         }
 547
 548         kdc->task = task;
 549
 550         /* Setup the KDC configuration */
 551         kdc->config = talloc(kdc, krb5_kdc_configuration);
 552         if (!kdc->config) {
 553                 task_server_terminate(task, "kdc: out of memory");
 554                 return;
 555         }
 556         krb5_kdc_default_config(kdc->config);
 557
 558         /* NAT and the like make this pointless, and painful */
 559         kdc->config->check_ticket_addresses = FALSE;
 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         ret = hdb_ldb_create(kdc, kdc->smb_krb5_context->krb5_context,
 582                              &kdc->config->db[0], NULL);
 583         if (ret != 0) {
 584                 DEBUG(1, ("kdc_task_init: hdb_ldb_create fails: %s\n",
 585                           smb_get_krb5_error_message(kdc->smb_krb5_context->krb5_context, ret, kdc)));
 586                 task_server_terminate(task, "kdc: hdb_ldb_create failed");
 587                 return;
 588         }
 589
 590         /* start listening on the configured network interfaces */
 591         status = kdc_startup_interfaces(kdc);
 592         if (!NT_STATUS_IS_OK(status)) {
 593                 task_server_terminate(task, "kdc failed to setup interfaces");
 594                 return;
 595         }
 596
 597         irpc_add_name(task->msg_ctx, "kdc_server");
 598 }
 599
 600
 601 /*
 602   called on startup of the KDC service
 603 */
 604 static NTSTATUS kdc_init(struct event_context *event_ctx,
 605                          const struct model_ops *model_ops)
 606 {
 607         return task_server_startup(event_ctx, model_ops, kdc_task_init);
 608 }
 609
 610 /* called at smbd startup - register ourselves as a server service */
 611 NTSTATUS server_service_kdc_init(void)
 612 {
 613         return register_server_service("kdc", kdc_init);
 614 }