source4/kdc/kdc-server.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    KDC related functions
   5
   6    Copyright (c) 2005-2008 Andrew Bartlett <abartlet@samba.org>
   7    Copyright (c) 2005      Andrew Tridgell <tridge@samba.org>
   8    Copyright (c) 2005      Stefan Metzmacher <metze@samba.org>
   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 3 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, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "param/param.h"
  26 #include "samba/process_model.h"
  27 #include "lib/tsocket/tsocket.h"
  28 #include "libcli/util/tstream.h"
  29 #include "kdc/kdc-server.h"
  30 #include "kdc/kdc-proxy.h"
  31 #include "lib/stream/packet.h"
  32
  33 #undef DBGC_CLASS
  34 #define DBGC_CLASS DBGC_KERBEROS
  35
  36 /*
  37  * State of an open tcp connection
  38  */
  39 struct kdc_tcp_connection {
  40         /* stream connection we belong to */
  41         struct stream_connection *conn;
  42
  43         /* the kdc_server the connection belongs to */
  44         struct kdc_socket *kdc_socket;
  45
  46         struct tstream_context *tstream;
  47
  48         struct tevent_queue *send_queue;
  49 };
  50
  51 struct kdc_tcp_call {
  52         struct kdc_tcp_connection *kdc_conn;
  53         DATA_BLOB in;
  54         DATA_BLOB out;
  55         uint8_t out_hdr[4];
  56         struct iovec out_iov[2];
  57 };
  58
  59 struct kdc_udp_call {
  60         struct kdc_udp_socket *sock;
  61         struct tsocket_address *src;
  62         DATA_BLOB in;
  63         DATA_BLOB out;
  64 };
  65
  66 static void kdc_udp_call_proxy_done(struct tevent_req *subreq);
  67 static void kdc_udp_call_sendto_done(struct tevent_req *subreq);
  68
  69 static void kdc_tcp_call_writev_done(struct tevent_req *subreq);
  70 static void kdc_tcp_call_proxy_done(struct tevent_req *subreq);
  71
  72 static void kdc_tcp_terminate_connection(struct kdc_tcp_connection *kdc_conn,
  73                                          const char *reason)
  74 {
  75         stream_terminate_connection(kdc_conn->conn, reason);
  76 }
  77
  78 static NTSTATUS kdc_proxy_unavailable_error(struct kdc_server *kdc,
  79                                             TALLOC_CTX *mem_ctx,
  80                                             DATA_BLOB *out)
  81 {
  82         krb5_error_code code;
  83         krb5_data enc_error;
  84
  85         code = smb_krb5_mk_error(kdc->smb_krb5_context->krb5_context,
  86                                  KRB5KDC_ERR_SVC_UNAVAILABLE,
  87                                  NULL,
  88                                  NULL,
  89                                  NULL,
  90                                  NULL,
  91                                  &enc_error);
  92         if (code != 0) {
  93                 DBG_WARNING("Unable to form krb5 error reply\n");
  94                 return NT_STATUS_INTERNAL_ERROR;
  95         }
  96
  97         *out = data_blob_talloc(mem_ctx, enc_error.data, enc_error.length);
  98         smb_krb5_free_data_contents(kdc->smb_krb5_context->krb5_context,
  99                                     &enc_error);
 100         if (!out->data) {
 101                 return NT_STATUS_NO_MEMORY;
 102         }
 103
 104         return NT_STATUS_OK;
 105 }
 106
 107 static void kdc_udp_call_loop(struct tevent_req *subreq)
 108 {
 109         struct kdc_udp_socket *sock = tevent_req_callback_data(subreq,
 110                                       struct kdc_udp_socket);
 111         struct kdc_udp_call *call;
 112         uint8_t *buf;
 113         ssize_t len;
 114         int sys_errno;
 115         kdc_code ret;
 116
 117         call = talloc(sock, struct kdc_udp_call);
 118         if (call == NULL) {
 119                 talloc_free(call);
 120                 goto done;
 121         }
 122         call->sock = sock;
 123
 124         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 125                                    call, &buf, &call->src);
 126         TALLOC_FREE(subreq);
 127         if (len == -1) {
 128                 talloc_free(call);
 129                 goto done;
 130         }
 131
 132         call->in.data = buf;
 133         call->in.length = len;
 134
 135         DBG_DEBUG("Received krb5 UDP packet of length %zu from %s\n",
 136                   call->in.length,
 137                   tsocket_address_string(call->src, call));
 138
 139         /* Call krb5 */
 140         ret = sock->kdc_socket->process(sock->kdc_socket->kdc,
 141                                        call,
 142                                        &call->in,
 143                                        &call->out,
 144                                        call->src,
 145                                        sock->kdc_socket->local_address,
 146                                        1 /* Datagram */);
 147         if (ret == KDC_ERROR) {
 148                 talloc_free(call);
 149                 goto done;
 150         }
 151
 152         if (ret == KDC_PROXY_REQUEST) {
 153                 uint16_t port;
 154
 155                 if (!sock->kdc_socket->kdc->am_rodc) {
 156                         DBG_ERR("proxying requested when not RODC\n");
 157                         talloc_free(call);
 158                         goto done;
 159                 }
 160
 161                 port = tsocket_address_inet_port(sock->kdc_socket->local_address);
 162
 163                 subreq = kdc_udp_proxy_send(call,
 164                                             sock->kdc_socket->kdc->task->event_ctx,
 165                                             sock->kdc_socket->kdc,
 166                                             port,
 167                                             call->in);
 168                 if (subreq == NULL) {
 169                         talloc_free(call);
 170                         goto done;
 171                 }
 172                 tevent_req_set_callback(subreq, kdc_udp_call_proxy_done, call);
 173                 goto done;
 174         }
 175
 176         subreq = tdgram_sendto_queue_send(call,
 177                                           sock->kdc_socket->kdc->task->event_ctx,
 178                                           sock->dgram,
 179                                           sock->send_queue,
 180                                           call->out.data,
 181                                           call->out.length,
 182                                           call->src);
 183         if (subreq == NULL) {
 184                 talloc_free(call);
 185                 goto done;
 186         }
 187         tevent_req_set_callback(subreq, kdc_udp_call_sendto_done, call);
 188
 189 done:
 190         subreq = tdgram_recvfrom_send(sock,
 191                                       sock->kdc_socket->kdc->task->event_ctx,
 192                                       sock->dgram);
 193         if (subreq == NULL) {
 194                 task_server_terminate(sock->kdc_socket->kdc->task,
 195                                       "no memory for tdgram_recvfrom_send",
 196                                       true);
 197                 return;
 198         }
 199         tevent_req_set_callback(subreq, kdc_udp_call_loop, sock);
 200 }
 201
 202 static void kdc_udp_call_proxy_done(struct tevent_req *subreq)
 203 {
 204         struct kdc_udp_call *call =
 205                 tevent_req_callback_data(subreq,
 206                 struct kdc_udp_call);
 207         NTSTATUS status;
 208
 209         status = kdc_udp_proxy_recv(subreq, call, &call->out);
 210         TALLOC_FREE(subreq);
 211         if (!NT_STATUS_IS_OK(status)) {
 212                 /* generate an error packet */
 213                 status = kdc_proxy_unavailable_error(call->sock->kdc_socket->kdc,
 214                                                      call, &call->out);
 215         }
 216
 217         if (!NT_STATUS_IS_OK(status)) {
 218                 talloc_free(call);
 219                 return;
 220         }
 221
 222         subreq = tdgram_sendto_queue_send(call,
 223                                           call->sock->kdc_socket->kdc->task->event_ctx,
 224                                           call->sock->dgram,
 225                                           call->sock->send_queue,
 226                                           call->out.data,
 227                                           call->out.length,
 228                                           call->src);
 229         if (subreq == NULL) {
 230                 talloc_free(call);
 231                 return;
 232         }
 233
 234         tevent_req_set_callback(subreq, kdc_udp_call_sendto_done, call);
 235 }
 236
 237 static void kdc_udp_call_sendto_done(struct tevent_req *subreq)
 238 {
 239         struct kdc_udp_call *call = tevent_req_callback_data(subreq,
 240                                        struct kdc_udp_call);
 241         int sys_errno;
 242
 243         tdgram_sendto_queue_recv(subreq, &sys_errno);
 244
 245         /* We don't care about errors */
 246
 247         talloc_free(call);
 248 }
 249
 250 static void kdc_tcp_call_loop(struct tevent_req *subreq)
 251 {
 252         struct kdc_tcp_connection *kdc_conn = tevent_req_callback_data(subreq,
 253                                       struct kdc_tcp_connection);
 254         struct kdc_tcp_call *call;
 255         NTSTATUS status;
 256         kdc_code ret;
 257
 258         call = talloc(kdc_conn, struct kdc_tcp_call);
 259         if (call == NULL) {
 260                 kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
 261                                 "no memory for kdc_tcp_call");
 262                 return;
 263         }
 264         call->kdc_conn = kdc_conn;
 265
 266         status = tstream_read_pdu_blob_recv(subreq,
 267                                             call,
 268                                             &call->in);
 269         TALLOC_FREE(subreq);
 270         if (!NT_STATUS_IS_OK(status)) {
 271                 const char *reason;
 272
 273                 reason = talloc_asprintf(call, "kdc_tcp_call_loop: "
 274                                          "tstream_read_pdu_blob_recv() - %s",
 275                                          nt_errstr(status));
 276                 if (!reason) {
 277                         reason = nt_errstr(status);
 278                 }
 279
 280                 kdc_tcp_terminate_connection(kdc_conn, reason);
 281                 return;
 282         }
 283
 284         DBG_DEBUG("Received krb5 TCP packet of length %zu from %s\n",
 285                   call->in.length,
 286                   tsocket_address_string(kdc_conn->conn->remote_address, call));
 287
 288         /* skip length header */
 289         call->in.data +=4;
 290         call->in.length -= 4;
 291
 292         /* Call krb5 */
 293         ret = kdc_conn->kdc_socket->process(kdc_conn->kdc_socket->kdc,
 294                                            call,
 295                                            &call->in,
 296                                            &call->out,
 297                                            kdc_conn->conn->remote_address,
 298                                            kdc_conn->conn->local_address,
 299                                            0 /* Stream */);
 300         if (ret == KDC_ERROR) {
 301                 kdc_tcp_terminate_connection(kdc_conn,
 302                                 "kdc_tcp_call_loop: process function failed");
 303                 return;
 304         }
 305
 306         if (ret == KDC_PROXY_REQUEST) {
 307                 uint16_t port;
 308
 309                 if (!kdc_conn->kdc_socket->kdc->am_rodc) {
 310                         kdc_tcp_terminate_connection(kdc_conn,
 311                                                      "kdc_tcp_call_loop: proxying requested when not RODC");
 312                         return;
 313                 }
 314                 port = tsocket_address_inet_port(kdc_conn->conn->local_address);
 315
 316                 subreq = kdc_tcp_proxy_send(call,
 317                                             kdc_conn->conn->event.ctx,
 318                                             kdc_conn->kdc_socket->kdc,
 319                                             port,
 320                                             call->in);
 321                 if (subreq == NULL) {
 322                         kdc_tcp_terminate_connection(kdc_conn,
 323                                 "kdc_tcp_call_loop: kdc_tcp_proxy_send failed");
 324                         return;
 325                 }
 326                 tevent_req_set_callback(subreq, kdc_tcp_call_proxy_done, call);
 327                 return;
 328         }
 329
 330         /* First add the length of the out buffer */
 331         RSIVAL(call->out_hdr, 0, call->out.length);
 332         call->out_iov[0].iov_base = (char *) call->out_hdr;
 333         call->out_iov[0].iov_len = 4;
 334
 335         call->out_iov[1].iov_base = (char *) call->out.data;
 336         call->out_iov[1].iov_len = call->out.length;
 337
 338         subreq = tstream_writev_queue_send(call,
 339                                            kdc_conn->conn->event.ctx,
 340                                            kdc_conn->tstream,
 341                                            kdc_conn->send_queue,
 342                                            call->out_iov, 2);
 343         if (subreq == NULL) {
 344                 kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
 345                                 "no memory for tstream_writev_queue_send");
 346                 return;
 347         }
 348         tevent_req_set_callback(subreq, kdc_tcp_call_writev_done, call);
 349
 350         /*
 351          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 352          * tstream_full_request_u32 provides the pdu length then.
 353          */
 354         subreq = tstream_read_pdu_blob_send(kdc_conn,
 355                                             kdc_conn->conn->event.ctx,
 356                                             kdc_conn->tstream,
 357                                             4, /* initial_read_size */
 358                                             tstream_full_request_u32,
 359                                             kdc_conn);
 360         if (subreq == NULL) {
 361                 kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_loop: "
 362                                 "no memory for tstream_read_pdu_blob_send");
 363                 return;
 364         }
 365         tevent_req_set_callback(subreq, kdc_tcp_call_loop, kdc_conn);
 366 }
 367
 368 static void kdc_tcp_call_proxy_done(struct tevent_req *subreq)
 369 {
 370         struct kdc_tcp_call *call = tevent_req_callback_data(subreq,
 371                         struct kdc_tcp_call);
 372         struct kdc_tcp_connection *kdc_conn = call->kdc_conn;
 373         NTSTATUS status;
 374
 375         status = kdc_tcp_proxy_recv(subreq, call, &call->out);
 376         TALLOC_FREE(subreq);
 377         if (!NT_STATUS_IS_OK(status)) {
 378                 /* generate an error packet */
 379                 status = kdc_proxy_unavailable_error(kdc_conn->kdc_socket->kdc,
 380                                                      call, &call->out);
 381         }
 382
 383         if (!NT_STATUS_IS_OK(status)) {
 384                 const char *reason;
 385
 386                 reason = talloc_asprintf(call, "kdc_tcp_call_proxy_done: "
 387                                          "kdc_proxy_unavailable_error - %s",
 388                                          nt_errstr(status));
 389                 if (!reason) {
 390                         reason = "kdc_tcp_call_proxy_done: kdc_proxy_unavailable_error() failed";
 391                 }
 392
 393                 kdc_tcp_terminate_connection(call->kdc_conn, reason);
 394                 return;
 395         }
 396
 397         /* First add the length of the out buffer */
 398         RSIVAL(call->out_hdr, 0, call->out.length);
 399         call->out_iov[0].iov_base = (char *) call->out_hdr;
 400         call->out_iov[0].iov_len = 4;
 401
 402         call->out_iov[1].iov_base = (char *) call->out.data;
 403         call->out_iov[1].iov_len = call->out.length;
 404
 405         subreq = tstream_writev_queue_send(call,
 406                                            kdc_conn->conn->event.ctx,
 407                                            kdc_conn->tstream,
 408                                            kdc_conn->send_queue,
 409                                            call->out_iov, 2);
 410         if (subreq == NULL) {
 411                 kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_proxy_done: "
 412                                 "no memory for tstream_writev_queue_send");
 413                 return;
 414         }
 415         tevent_req_set_callback(subreq, kdc_tcp_call_writev_done, call);
 416
 417         /*
 418          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 419          * tstream_full_request_u32 provides the pdu length then.
 420          */
 421         subreq = tstream_read_pdu_blob_send(kdc_conn,
 422                                             kdc_conn->conn->event.ctx,
 423                                             kdc_conn->tstream,
 424                                             4, /* initial_read_size */
 425                                             tstream_full_request_u32,
 426                                             kdc_conn);
 427         if (subreq == NULL) {
 428                 kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_call_proxy_done: "
 429                                 "no memory for tstream_read_pdu_blob_send");
 430                 return;
 431         }
 432         tevent_req_set_callback(subreq, kdc_tcp_call_loop, kdc_conn);
 433 }
 434
 435 static void kdc_tcp_call_writev_done(struct tevent_req *subreq)
 436 {
 437         struct kdc_tcp_call *call = tevent_req_callback_data(subreq,
 438                         struct kdc_tcp_call);
 439         int sys_errno;
 440         int rc;
 441
 442         rc = tstream_writev_queue_recv(subreq, &sys_errno);
 443         TALLOC_FREE(subreq);
 444         if (rc == -1) {
 445                 const char *reason;
 446
 447                 reason = talloc_asprintf(call, "kdc_tcp_call_writev_done: "
 448                                          "tstream_writev_queue_recv() - %d:%s",
 449                                          sys_errno, strerror(sys_errno));
 450                 if (!reason) {
 451                         reason = "kdc_tcp_call_writev_done: tstream_writev_queue_recv() failed";
 452                 }
 453
 454                 kdc_tcp_terminate_connection(call->kdc_conn, reason);
 455                 return;
 456         }
 457
 458         /* We don't care about errors */
 459
 460         talloc_free(call);
 461 }
 462
 463 /*
 464   called when we get a new connection
 465 */
 466 static void kdc_tcp_accept(struct stream_connection *conn)
 467 {
 468         struct kdc_socket *kdc_socket;
 469         struct kdc_tcp_connection *kdc_conn;
 470         struct tevent_req *subreq;
 471         int rc;
 472
 473         kdc_conn = talloc_zero(conn, struct kdc_tcp_connection);
 474         if (kdc_conn == NULL) {
 475                 stream_terminate_connection(conn,
 476                                 "kdc_tcp_accept: out of memory");
 477                 return;
 478         }
 479
 480         kdc_conn->send_queue = tevent_queue_create(conn, "kdc_tcp_accept");
 481         if (kdc_conn->send_queue == NULL) {
 482                 stream_terminate_connection(conn,
 483                                 "kdc_tcp_accept: out of memory");
 484                 return;
 485         }
 486
 487         kdc_socket = talloc_get_type(conn->private_data, struct kdc_socket);
 488
 489         TALLOC_FREE(conn->event.fde);
 490
 491         rc = tstream_bsd_existing_socket(kdc_conn,
 492                         socket_get_fd(conn->socket),
 493                         &kdc_conn->tstream);
 494         if (rc < 0) {
 495                 stream_terminate_connection(conn,
 496                                 "kdc_tcp_accept: out of memory");
 497                 return;
 498         }
 499         /* as server we want to fail early */
 500         tstream_bsd_fail_readv_first_error(kdc_conn->tstream, true);
 501
 502         kdc_conn->conn = conn;
 503         kdc_conn->kdc_socket = kdc_socket;
 504         conn->private_data = kdc_conn;
 505
 506         /*
 507          * The krb5 tcp pdu's has the length as 4 byte (initial_read_size),
 508          * tstream_full_request_u32 provides the pdu length then.
 509          */
 510         subreq = tstream_read_pdu_blob_send(kdc_conn,
 511                                             kdc_conn->conn->event.ctx,
 512                                             kdc_conn->tstream,
 513                                             4, /* initial_read_size */
 514                                             tstream_full_request_u32,
 515                                             kdc_conn);
 516         if (subreq == NULL) {
 517                 kdc_tcp_terminate_connection(kdc_conn, "kdc_tcp_accept: "
 518                                 "no memory for tstream_read_pdu_blob_send");
 519                 return;
 520         }
 521         tevent_req_set_callback(subreq, kdc_tcp_call_loop, kdc_conn);
 522 }
 523
 524 static void kdc_tcp_recv(struct stream_connection *conn, uint16_t flags)
 525 {
 526         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private_data,
 527                                                              struct kdc_tcp_connection);
 528         /* this should never be triggered! */
 529         kdc_tcp_terminate_connection(kdcconn, "kdc_tcp_recv: called");
 530 }
 531
 532 static void kdc_tcp_send(struct stream_connection *conn, uint16_t flags)
 533 {
 534         struct kdc_tcp_connection *kdcconn = talloc_get_type(conn->private_data,
 535                                                              struct kdc_tcp_connection);
 536         /* this should never be triggered! */
 537         kdc_tcp_terminate_connection(kdcconn, "kdc_tcp_send: called");
 538 }
 539
 540 static const struct stream_server_ops kdc_tcp_stream_ops = {
 541         .name                   = "kdc_tcp",
 542         .accept_connection      = kdc_tcp_accept,
 543         .recv_handler           = kdc_tcp_recv,
 544         .send_handler           = kdc_tcp_send
 545 };
 546
 547 /*
 548  * Start listening on the given address
 549  */
 550 NTSTATUS kdc_add_socket(struct kdc_server *kdc,
 551                         const struct model_ops *model_ops,
 552                         const char *name,
 553                         const char *address,
 554                         uint16_t port,
 555                         kdc_process_fn_t process,
 556                         bool udp_only)
 557 {
 558         struct kdc_socket *kdc_socket;
 559         struct kdc_udp_socket *kdc_udp_socket;
 560         struct tevent_req *udpsubreq;
 561         NTSTATUS status;
 562         int ret;
 563
 564         kdc_socket = talloc(kdc, struct kdc_socket);
 565         NT_STATUS_HAVE_NO_MEMORY(kdc_socket);
 566
 567         kdc_socket->kdc = kdc;
 568         kdc_socket->process = process;
 569
 570         ret = tsocket_address_inet_from_strings(kdc_socket, "ip",
 571                                                 address, port,
 572                                                 &kdc_socket->local_address);
 573         if (ret != 0) {
 574                 status = map_nt_error_from_unix_common(errno);
 575                 return status;
 576         }
 577
 578         if (!udp_only) {
 579                 status = stream_setup_socket(kdc->task,
 580                                              kdc->task->event_ctx,
 581                                              kdc->task->lp_ctx,
 582                                              model_ops,
 583                                              &kdc_tcp_stream_ops,
 584                                              "ip", address, &port,
 585                                              lpcfg_socket_options(kdc->task->lp_ctx),
 586                                              kdc_socket,
 587                                              kdc->task->process_context);
 588                 if (!NT_STATUS_IS_OK(status)) {
 589                         DBG_ERR("Failed to bind to %s:%u TCP - %s\n",
 590                                 address, port, nt_errstr(status));
 591                         talloc_free(kdc_socket);
 592                         return status;
 593                 }
 594         }
 595
 596         kdc_udp_socket = talloc(kdc_socket, struct kdc_udp_socket);
 597         NT_STATUS_HAVE_NO_MEMORY(kdc_udp_socket);
 598
 599         kdc_udp_socket->kdc_socket = kdc_socket;
 600
 601         ret = tdgram_inet_udp_socket(kdc_socket->local_address,
 602                                      NULL,
 603                                      kdc_udp_socket,
 604                                      &kdc_udp_socket->dgram);
 605         if (ret != 0) {
 606                 status = map_nt_error_from_unix_common(errno);
 607                 DBG_ERR("Failed to bind to %s:%u UDP - %s\n",
 608                         address, port, nt_errstr(status));
 609                 return status;
 610         }
 611
 612         kdc_udp_socket->send_queue = tevent_queue_create(kdc_udp_socket,
 613                                                          "kdc_udp_send_queue");
 614         NT_STATUS_HAVE_NO_MEMORY(kdc_udp_socket->send_queue);
 615
 616         udpsubreq = tdgram_recvfrom_send(kdc_udp_socket,
 617                                          kdc->task->event_ctx,
 618                                          kdc_udp_socket->dgram);
 619         NT_STATUS_HAVE_NO_MEMORY(udpsubreq);
 620         tevent_req_set_callback(udpsubreq, kdc_udp_call_loop, kdc_udp_socket);
 621
 622         return NT_STATUS_OK;
 623 }