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
  35 /* hold all the info needed to send a reply */
  36 struct kdc_reply {
  37         struct kdc_reply *next, *prev;
  38         const char *dest_address;
  39         int dest_port;
  40         DATA_BLOB packet;
  41 };
  42
  43 /*
  44   top level context structure for the kdc server
  45 */
  46 struct kdc_server {
  47         struct task_server *task;
  48         krb5_kdc_configuration *config;
  49         struct smb_krb5_context *smb_krb5_context;
  50 };
  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         int (*process)(krb5_context context,
  62                        krb5_kdc_configuration *config,
  63                        unsigned char *buf,
  64                        size_t len,
  65                        krb5_data *reply,
  66                        const char *from,
  67                        struct sockaddr *addr);
  68 };
  69 /*
  70   state of an open tcp connection
  71 */
  72 struct kdc_tcp_connection {
  73         /* stream connection we belong to */
  74         struct stream_connection *conn;
  75
  76         /* the kdc_server the connection belongs to */
  77         struct kdc_server *kdc;
  78
  79         /* the partial data we've receiced yet */
  80         DATA_BLOB partial;
  81
  82         /* the amount that we used yet from the partial buffer */
  83         uint32_t partial_read;
  84
  85         /* prevent loops when we use half async code, while processing a requuest */
  86         BOOL processing;
  87
  88         /* a queue of outgoing replies that have been deferred */
  89         struct data_blob_list_item *send_queue;
  90
  91         int (*process)(krb5_context context,
  92                                              krb5_kdc_configuration *config,
  93                                              unsigned char *buf,
  94                                              size_t len,
  95                                              krb5_data *reply,
  96                                              const char *from,
  97                                              struct sockaddr *addr);
  98 };
  99
 100 /*
 101   handle fd send events on a KDC socket
 102 */
 103 static void kdc_send_handler(struct kdc_socket *kdc_socket)
 104 {
 105         while (kdc_socket->send_queue) {
 106                 struct kdc_reply *rep = kdc_socket->send_queue;
 107                 NTSTATUS status;
 108                 size_t sendlen;
 109
 110                 status = socket_sendto(kdc_socket->sock, &rep->packet, &sendlen, 0,
 111                                        rep->dest_address, rep->dest_port);
 112                 if (NT_STATUS_EQUAL(status, STATUS_MORE_ENTRIES)) {
 113                         break;
 114                 }
 115
 116                 DLIST_REMOVE(kdc_socket->send_queue, rep);
 117                 talloc_free(rep);
 118         }
 119
 120         if (kdc_socket->send_queue == NULL) {
 121                 EVENT_FD_NOT_WRITEABLE(kdc_socket->fde);
 122         }
 123 }
 124
 125
 126 /*
 127   handle fd recv events on a KDC socket
 128 */
 129 static void kdc_recv_handler(struct kdc_socket *kdc_socket)
 130 {
 131         NTSTATUS status;
 132         TALLOC_CTX *tmp_ctx = talloc_new(kdc_socket);
 133         DATA_BLOB blob;
 134         struct kdc_reply *rep;
 135         krb5_data reply;
 136         size_t nread, dsize;
 137         const char *src_addr;
 138         int src_port;
 139         struct sockaddr_in src_sock_addr;
 140         struct ipv4_addr addr;
 141         int ret;
 142
 143         status = socket_pending(kdc_socket->sock, &dsize);
 144         if (!NT_STATUS_IS_OK(status)) {
 145                 talloc_free(tmp_ctx);
 146                 return;
 147         }
 148
 149         blob = data_blob_talloc(kdc_socket, NULL, dsize);
 150         if (blob.data == NULL) {
 151                 /* hope this is a temporary low memory condition */
 152                 talloc_free(tmp_ctx);
 153                 return;
 154         }
 155
 156         status = socket_recvfrom(kdc_socket->sock, blob.data, blob.length, &nread, 0,
 157                                  &src_addr, &src_port);
 158         if (!NT_STATUS_IS_OK(status)) {
 159                 talloc_free(tmp_ctx);
 160                 return;
 161         }
 162         talloc_steal(tmp_ctx, src_addr);
 163         blob.length = nread;
 164
 165         DEBUG(2,("Received krb5 UDP packet of length %u from %s:%u\n",
 166                  blob.length, src_addr, (uint16_t)src_port));
 167
 168         /* TODO:  This really should be in a utility function somewhere */
 169         ZERO_STRUCT(src_sock_addr);
 170 #ifdef HAVE_SOCK_SIN_LEN
 171         src_sock_addr.sin_len         = sizeof(src_sock_addr);
 172 #endif
 173         addr                     = interpret_addr2(src_addr);
 174         src_sock_addr.sin_addr.s_addr = addr.addr;
 175         src_sock_addr.sin_port        = htons(src_port);
 176         src_sock_addr.sin_family      = PF_INET;
 177
 178         /* Call krb5 */
 179         ret = kdc_socket->process(kdc_socket->kdc->smb_krb5_context->krb5_context,
 180                                   kdc_socket->kdc->config,
 181                                   blob.data, blob.length,
 182                                   &reply,
 183                                   src_addr,
 184                                   (struct sockaddr *)&src_sock_addr);
 185         if (ret == -1) {
 186                 talloc_free(tmp_ctx);
 187                 return;
 188         }
 189
 190         /* queue a pending reply */
 191         rep = talloc(kdc_socket, struct kdc_reply);
 192         if (rep == NULL) {
 193                 krb5_data_free(&reply);
 194                 talloc_free(tmp_ctx);
 195                 return;
 196         }
 197         rep->dest_address = talloc_steal(rep, src_addr);
 198         rep->dest_port    = src_port;
 199         rep->packet       = data_blob_talloc(rep, reply.data, reply.length);
 200         krb5_data_free(&reply);
 201
 202         if (rep->packet.data == NULL) {
 203                 talloc_free(rep);
 204                 talloc_free(tmp_ctx);
 205                 return;
 206         }
 207
 208         DLIST_ADD_END(kdc_socket->send_queue, rep, struct kdc_reply *);
 209         EVENT_FD_WRITEABLE(kdc_socket->fde);
 210         talloc_free(tmp_ctx);
 211 }
 212
 213 /*
 214   handle fd events on a KDC socket
 215 */
 216 static void kdc_socket_handler(struct event_context *ev, struct fd_event *fde,
 217                                uint16_t flags, void *private)
 218 {
 219         struct kdc_socket *kdc_socket = talloc_get_type(private, struct kdc_socket);
 220         if (flags & EVENT_FD_WRITE) {
 221                 kdc_send_handler(kdc_socket);
 222         }
 223         if (flags & EVENT_FD_READ) {
 224                 kdc_recv_handler(kdc_socket);
 225         }
 226 }
 227
 228 static void kdc_tcp_terminate_connection(struct kdc_tcp_connection *kdcconn, const char *reason)
 229 {
 230         stream_terminate_connection(kdcconn->conn, reason);
 231 }
 232
 233 /*
 234   called when we get a new connection
 235 */
 236 static void kdc_tcp_accept(struct stream_connection *conn)
 237 {
 238         struct kdc_server *kdc = talloc_get_type(conn->private, struct kdc_server);
 239         struct kdc_tcp_connection *kdcconn;
 240
 241         kdcconn = talloc_zero(conn, struct kdc_tcp_connection);
 242         if (!kdcconn) {
 243                 stream_terminate_connection(conn, "kdc_tcp_accept: out of memory");
 244                 return;
 245         }
 246         kdcconn->conn    = conn;
 247         kdcconn->kdc     = kdc;
 248         kdcconn->process = krb5_kdc_process_krb5_request;
 249         conn->private    = kdcconn;
 250 }
 251
 252 /*
 253   receive some data on a KDC connection
 254 */
 255 static void kdc_tcp_recv(struct stream_connection *conn, uint16_t flags)
 256 {
 257         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private, struct kdc_tcp_connection);
 258         NTSTATUS status = NT_STATUS_UNSUCCESSFUL;
 259         TALLOC_CTX *tmp_ctx = talloc_new(kdcconn);
 260         struct data_blob_list_item *rep;
 261         krb5_data reply;
 262         size_t nread;
 263         const char *src_addr;
 264         int src_port;
 265         struct sockaddr_in src_sock_addr;
 266         struct ipv4_addr addr;
 267         int ret;
 268
 269         /* avoid recursion, because of half async code */
 270         if (kdcconn->processing) {
 271                 EVENT_FD_NOT_READABLE(conn->event.fde);
 272                 return;
 273         }
 274
 275         if (kdcconn->partial.length == 0) {
 276                 kdcconn->partial = data_blob_talloc(kdcconn, NULL, 4);
 277                 if (!kdcconn->partial.data) goto nomem;
 278
 279                 kdcconn->partial_read = 0;
 280         }
 281
 282         /* read in the packet length */
 283         if (kdcconn->partial_read < 4) {
 284                 uint32_t packet_length;
 285
 286                 status = socket_recv(conn->socket,
 287                                      kdcconn->partial.data + kdcconn->partial_read,
 288                                      4 - kdcconn->partial_read,
 289                                      &nread, 0);
 290                 if (NT_STATUS_IS_ERR(status)) goto failed;
 291                 if (!NT_STATUS_IS_OK(status)) return;
 292
 293                 kdcconn->partial_read += nread;
 294                 if (kdcconn->partial_read != 4) return;
 295
 296                 packet_length = RIVAL(kdcconn->partial.data, 0) + 4;
 297
 298                 kdcconn->partial.data = talloc_realloc(kdcconn, kdcconn->partial.data,
 299                                                        uint8_t, packet_length);
 300                 if (!kdcconn->partial.data) goto nomem;
 301
 302                 kdcconn->partial.length = packet_length;
 303         }
 304
 305         /* read in the body */
 306         status = socket_recv(conn->socket,
 307                              kdcconn->partial.data + kdcconn->partial_read,
 308                              kdcconn->partial.length - kdcconn->partial_read,
 309                              &nread, 0);
 310         if (NT_STATUS_IS_ERR(status)) goto failed;
 311         if (!NT_STATUS_IS_OK(status)) return;
 312
 313         kdcconn->partial_read += nread;
 314         if (kdcconn->partial_read != kdcconn->partial.length) return;
 315
 316         /*
 317          * we have parsed the request, so we can reset the kdcconn->partial_read,
 318          * maybe we could also free kdcconn->partial, but for now we keep it,
 319          * and overwrite it the next time
 320          */
 321         kdcconn->partial_read = 0;
 322
 323         src_addr = socket_get_peer_addr(kdcconn->conn->socket, tmp_ctx);
 324         if (!src_addr) goto nomem;
 325         src_port = socket_get_peer_port(kdcconn->conn->socket);
 326
 327         DEBUG(2,("Received krb5 TCP packet of length %u from %s:%u\n",
 328                  kdcconn->partial.length - 4, src_addr, src_port));
 329
 330         /* TODO:  This really should be in a utility function somewhere */
 331         ZERO_STRUCT(src_sock_addr);
 332 #ifdef HAVE_SOCK_SIN_LEN
 333         src_sock_addr.sin_len           = sizeof(src_sock_addr);
 334 #endif
 335         addr                            = interpret_addr2(src_addr);
 336         src_sock_addr.sin_addr.s_addr   = addr.addr;
 337         src_sock_addr.sin_port          = htons(src_port);
 338         src_sock_addr.sin_family        = PF_INET;
 339
 340         /* Call krb5 */
 341         kdcconn->processing = True;
 342         ret = kdcconn->process(kdcconn->kdc->smb_krb5_context->krb5_context,
 343                                kdcconn->kdc->config,
 344                                kdcconn->partial.data + 4, kdcconn->partial.length - 4,
 345                                &reply,
 346                                src_addr,
 347                                (struct sockaddr *)&src_sock_addr);
 348         kdcconn->processing = False;
 349         if (ret == -1) {
 350                 status = NT_STATUS_INTERNAL_ERROR;
 351                 goto failed;
 352         }
 353
 354         /* and now encode the reply */
 355         rep = talloc(kdcconn, struct data_blob_list_item);
 356         if (!rep) {
 357                 krb5_data_free(&reply);
 358                 goto nomem;
 359         }
 360
 361         rep->blob = data_blob_talloc(rep, NULL, reply.length + 4);
 362         if (!rep->blob.data)  {
 363                 krb5_data_free(&reply);
 364                 goto nomem;
 365         }
 366
 367         RSIVAL(rep->blob.data, 0, reply.length);
 368         memcpy(rep->blob.data + 4, reply.data, reply.length);
 369         krb5_data_free(&reply);
 370
 371         if (!kdcconn->send_queue) {
 372                 EVENT_FD_WRITEABLE(kdcconn->conn->event.fde);
 373         }
 374         DLIST_ADD_END(kdcconn->send_queue, rep, struct data_blob_list_item *);
 375
 376         EVENT_FD_READABLE(kdcconn->conn->event.fde);
 377
 378         /* the call isn't needed any more */
 379         talloc_free(tmp_ctx);
 380         return;
 381 nomem:
 382         status = NT_STATUS_NO_MEMORY;
 383 failed:
 384         kdc_tcp_terminate_connection(kdcconn, nt_errstr(status));
 385 }
 386
 387 /*
 388   called when we can write to a connection
 389 */
 390 static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
 391 {
 392         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private, struct kdc_tcp_connection);
 393         NTSTATUS status;
 394
 395         while (kdcconn->send_queue) {
 396                 struct data_blob_list_item *q = kdcconn->send_queue;
 397                 size_t sendlen;
 398
 399                 status = socket_send(conn->socket, &q->blob, &sendlen, 0);
 400                 if (NT_STATUS_IS_ERR(status)) goto failed;
 401                 if (!NT_STATUS_IS_OK(status)) return;
 402
 403                 q->blob.length -= sendlen;
 404                 q->blob.data   += sendlen;
 405
 406                 if (q->blob.length == 0) {
 407                         DLIST_REMOVE(kdcconn->send_queue, q);
 408                         talloc_free(q);
 409                 }
 410         }
 411
 412         EVENT_FD_NOT_WRITEABLE(conn->event.fde);
 413         return;
 414 failed:
 415         kdc_tcp_terminate_connection(kdcconn, nt_errstr(status));
 416 }
 417
 418 static const struct stream_server_ops kdc_tcp_stream_ops = {
 419         .name                   = "kdc_tcp",
 420         .accept_connection      = kdc_tcp_accept,
 421         .recv_handler           = kdc_tcp_recv,
 422         .send_handler           = kdc_tcp_send
 423 };
 424
 425 /*
 426   start listening on the given address
 427 */
 428 static NTSTATUS kdc_add_socket(struct kdc_server *kdc, const char *address)
 429 {
 430         const struct model_ops *model_ops;
 431         struct kdc_socket *kdc_socket;
 432         NTSTATUS status;
 433         uint16_t port = lp_krb5_port();
 434
 435         kdc_socket = talloc(kdc, struct kdc_socket);
 436         NT_STATUS_HAVE_NO_MEMORY(kdc_socket);
 437
 438         status = socket_create("ip", SOCKET_TYPE_DGRAM, &kdc_socket->sock, 0);
 439         if (!NT_STATUS_IS_OK(status)) {
 440                 talloc_free(kdc_socket);
 441                 return status;
 442         }
 443
 444         kdc_socket->kdc = kdc;
 445         kdc_socket->send_queue = NULL;
 446         kdc_socket->process = krb5_kdc_process_krb5_request;
 447
 448         talloc_steal(kdc_socket, kdc_socket->sock);
 449
 450         kdc_socket->fde = event_add_fd(kdc->task->event_ctx, kdc,
 451                                        socket_get_fd(kdc_socket->sock), EVENT_FD_READ,
 452                                        kdc_socket_handler, kdc_socket);
 453
 454         status = socket_listen(kdc_socket->sock, address, port, 0, 0);
 455         if (!NT_STATUS_IS_OK(status)) {
 456                 DEBUG(0,("Failed to bind to %s:%d UDP - %s\n",
 457                          address, port, nt_errstr(status)));
 458                 talloc_free(kdc_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, &kdc_tcp_stream_ops,
 473                                      "ip", address, &port, kdc);
 474         if (!NT_STATUS_IS_OK(status)) {
 475                 DEBUG(0,("Failed to bind to %s:%u TCP - %s\n",
 476                          address, port, nt_errstr(status)));
 477                 talloc_free(kdc_socket);
 478                 return status;
 479         }
 480
 481         return NT_STATUS_OK;
 482 }
 483
 484
 485 /*
 486   setup our listening sockets on the configured network interfaces
 487 */
 488 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc)
 489 {
 490         int num_interfaces = iface_count();
 491         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 492         NTSTATUS status;
 493
 494         /* if we are allowing incoming packets from any address, then
 495            we need to bind to the wildcard address */
 496         if (!lp_bind_interfaces_only()) {
 497                 status = kdc_add_socket(kdc, "0.0.0.0");
 498                 NT_STATUS_NOT_OK_RETURN(status);
 499         } else {
 500                 int i;
 501
 502                 for (i=0; i<num_interfaces; i++) {
 503                         const char *address = talloc_strdup(tmp_ctx, iface_n_ip(i));
 504                         status = kdc_add_socket(kdc, address);
 505                         NT_STATUS_NOT_OK_RETURN(status);
 506                 }
 507         }
 508
 509         talloc_free(tmp_ctx);
 510
 511         return NT_STATUS_OK;
 512 }
 513
 514 /*
 515   startup the kdc task
 516 */
 517 static void kdc_task_init(struct task_server *task)
 518 {
 519         struct kdc_server *kdc;
 520         NTSTATUS status;
 521         krb5_error_code ret;
 522
 523         if (iface_count() == 0) {
 524                 task_server_terminate(task, "kdc: no network interfaces configured");
 525                 return;
 526         }
 527
 528         kdc = talloc(task, struct kdc_server);
 529         if (kdc == NULL) {
 530                 task_server_terminate(task, "kdc: out of memory");
 531                 return;
 532         }
 533
 534         kdc->task = task;
 535
 536         /* Setup the KDC configuration */
 537         kdc->config = talloc(kdc, krb5_kdc_configuration);
 538         if (!kdc->config) {
 539                 task_server_terminate(task, "kdc: out of memory");
 540                 return;
 541         }
 542         krb5_kdc_default_config(kdc->config);
 543
 544         /* NAT and the like make this pointless, and painful */
 545         kdc->config->check_ticket_addresses = FALSE;
 546
 547         initialize_krb5_error_table();
 548
 549         ret = smb_krb5_init_context(kdc, &kdc->smb_krb5_context);
 550         if (ret) {
 551                 DEBUG(1,("kdc_task_init: krb5_init_context failed (%s)\n",
 552                          error_message(ret)));
 553                 task_server_terminate(task, "kdc: krb5_init_context failed");
 554                 return;
 555         }
 556
 557         krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
 558
 559         kdc->config->logf = kdc->smb_krb5_context->logf;
 560         kdc->config->db = talloc(kdc->config, struct HDB *);
 561         if (!kdc->config->db) {
 562                 task_server_terminate(task, "kdc: out of memory");
 563                 return;
 564         }
 565         kdc->config->num_db = 1;
 566
 567         ret = hdb_ldb_create(kdc, kdc->smb_krb5_context->krb5_context,
 568                              &kdc->config->db[0], lp_sam_url());
 569         if (ret != 0) {
 570                 DEBUG(1, ("kdc_task_init: hdb_ldb_create fails: %s\n",
 571                           smb_get_krb5_error_message(kdc->smb_krb5_context->krb5_context, ret, kdc)));
 572                 task_server_terminate(task, "kdc: hdb_ldb_create failed");
 573                 return;
 574         }
 575
 576         /* start listening on the configured network interfaces */
 577         status = kdc_startup_interfaces(kdc);
 578         if (!NT_STATUS_IS_OK(status)) {
 579                 task_server_terminate(task, "kdc failed to setup interfaces");
 580                 return;
 581         }
 582
 583         irpc_add_name(task->msg_ctx, "kdc_server");
 584 }
 585
 586
 587 /*
 588   called on startup of the KDC service
 589 */
 590 static NTSTATUS kdc_init(struct event_context *event_ctx,
 591                          const struct model_ops *model_ops)
 592 {
 593         return task_server_startup(event_ctx, model_ops, kdc_task_init);
 594 }
 595
 596 /* called at smbd startup - register ourselves as a server service */
 597 NTSTATUS server_service_kdc_init(void)
 598 {
 599         return register_server_service("kdc", kdc_init);
 600 }