source4/kdc/proxy.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    KDC Server request proxying
   5
   6    Copyright (C) Andrew Tridgell        2010
   7    Copyright (C) Andrew Bartlett        2010
   8    Copyright (C) Stefan Metzmacher      2011
   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 "smbd/process_model.h"
  26 #include "lib/tsocket/tsocket.h"
  27 #include "libcli/util/tstream.h"
  28 #include "lib/util/tevent_ntstatus.h"
  29 #include "lib/stream/packet.h"
  30 #include "kdc/kdc-glue.h"
  31 #include "dsdb/samdb/samdb.h"
  32 #include "libcli/composite/composite.h"
  33 #include "libcli/resolve/resolve.h"
  34
  35
  36 /*
  37   get a list of our replication partners from repsFrom, returning it in *proxy_list
  38  */
  39 static WERROR kdc_proxy_get_writeable_dcs(struct kdc_server *kdc, TALLOC_CTX *mem_ctx, char ***proxy_list)
  40 {
  41         WERROR werr;
  42         uint32_t count, i;
  43         struct repsFromToBlob *reps;
  44
  45         werr = dsdb_loadreps(kdc->samdb, mem_ctx, ldb_get_default_basedn(kdc->samdb), "repsFrom", &reps, &count);
  46         W_ERROR_NOT_OK_RETURN(werr);
  47
  48         if (count == 0) {
  49                 /* we don't have any DCs to replicate with. Very
  50                    strange for a RODC */
  51                 DEBUG(1,(__location__ ": No replication sources for RODC in KDC proxy\n"));
  52                 talloc_free(reps);
  53                 return WERR_DS_DRA_NO_REPLICA;
  54         }
  55
  56         (*proxy_list) = talloc_array(mem_ctx, char *, count+1);
  57         W_ERROR_HAVE_NO_MEMORY_AND_FREE(*proxy_list, reps);
  58
  59         talloc_steal(*proxy_list, reps);
  60
  61         for (i=0; i<count; i++) {
  62                 const char *dns_name = NULL;
  63                 if (reps->version == 1) {
  64                         dns_name = reps->ctr.ctr1.other_info->dns_name;
  65                 } else if (reps->version == 2) {
  66                         dns_name = reps->ctr.ctr2.other_info->dns_name1;
  67                 }
  68                 (*proxy_list)[i] = talloc_strdup(*proxy_list, dns_name);
  69                 W_ERROR_HAVE_NO_MEMORY_AND_FREE((*proxy_list)[i], *proxy_list);
  70         }
  71         (*proxy_list)[i] = NULL;
  72
  73         talloc_free(reps);
  74
  75         return WERR_OK;
  76 }
  77
  78
  79 struct kdc_udp_proxy_state {
  80         struct tevent_context *ev;
  81         struct kdc_server *kdc;
  82         uint16_t port;
  83         DATA_BLOB in;
  84         DATA_BLOB out;
  85         char **proxy_list;
  86         uint32_t next_proxy;
  87         struct {
  88                 struct nbt_name name;
  89                 const char *ip;
  90                 struct tdgram_context *dgram;
  91         } proxy;
  92 };
  93
  94
  95 static void kdc_udp_next_proxy(struct tevent_req *req);
  96
  97 struct tevent_req *kdc_udp_proxy_send(TALLOC_CTX *mem_ctx,
  98                                       struct tevent_context *ev,
  99                                       struct kdc_server *kdc,
 100                                       uint16_t port,
 101                                       DATA_BLOB in)
 102 {
 103         struct tevent_req *req;
 104         struct kdc_udp_proxy_state *state;
 105         WERROR werr;
 106
 107         req = tevent_req_create(mem_ctx, &state,
 108                                 struct kdc_udp_proxy_state);
 109         if (req == NULL) {
 110                 return NULL;
 111         }
 112         state->ev = ev;
 113         state->kdc  = kdc;
 114         state->port = port;
 115         state->in = in;
 116
 117         werr = kdc_proxy_get_writeable_dcs(kdc, state, &state->proxy_list);
 118         if (!W_ERROR_IS_OK(werr)) {
 119                 NTSTATUS status = werror_to_ntstatus(werr);
 120                 tevent_req_nterror(req, status);
 121                 return tevent_req_post(req, ev);
 122         }
 123
 124         kdc_udp_next_proxy(req);
 125         if (!tevent_req_is_in_progress(req)) {
 126                 return tevent_req_post(req, ev);
 127         }
 128
 129         return req;
 130 }
 131
 132 static void kdc_udp_proxy_resolve_done(struct composite_context *csubreq);
 133
 134 /*
 135   try the next proxy in the list
 136  */
 137 static void kdc_udp_next_proxy(struct tevent_req *req)
 138 {
 139         struct kdc_udp_proxy_state *state =
 140                 tevent_req_data(req,
 141                 struct kdc_udp_proxy_state);
 142         const char *proxy_dnsname = state->proxy_list[state->next_proxy];
 143         struct composite_context *csubreq;
 144
 145         if (proxy_dnsname == NULL) {
 146                 tevent_req_nterror(req, NT_STATUS_NO_LOGON_SERVERS);
 147                 return;
 148         }
 149
 150         state->next_proxy++;
 151
 152         /* make sure we close the socket of the last try */
 153         TALLOC_FREE(state->proxy.dgram);
 154         ZERO_STRUCT(state->proxy);
 155
 156         make_nbt_name(&state->proxy.name, proxy_dnsname, 0);
 157
 158         csubreq = resolve_name_ex_send(lpcfg_resolve_context(state->kdc->task->lp_ctx),
 159                                        state,
 160                                        RESOLVE_NAME_FLAG_FORCE_DNS,
 161                                        0,
 162                                        &state->proxy.name,
 163                                        state->ev);
 164         if (tevent_req_nomem(csubreq, req)) {
 165                 return;
 166         }
 167         csubreq->async.fn = kdc_udp_proxy_resolve_done;
 168         csubreq->async.private_data = req;
 169 }
 170
 171 static void kdc_udp_proxy_sendto_done(struct tevent_req *subreq);
 172 static void kdc_udp_proxy_recvfrom_done(struct tevent_req *subreq);
 173
 174 static void kdc_udp_proxy_resolve_done(struct composite_context *csubreq)
 175 {
 176         struct tevent_req *req =
 177                 talloc_get_type_abort(csubreq->async.private_data,
 178                 struct tevent_req);
 179         struct kdc_udp_proxy_state *state =
 180                 tevent_req_data(req,
 181                 struct kdc_udp_proxy_state);
 182         NTSTATUS status;
 183         struct tevent_req *subreq;
 184         struct tsocket_address *local_addr, *proxy_addr;
 185         int ret;
 186
 187         status = resolve_name_recv(csubreq, state, &state->proxy.ip);
 188         if (!NT_STATUS_IS_OK(status)) {
 189                 DEBUG(0,("Unable to resolve proxy[%s] - %s\n",
 190                         state->proxy.name.name, nt_errstr(status)));
 191                 kdc_udp_next_proxy(req);
 192                 return;
 193         }
 194
 195         /* get an address for us to use locally */
 196         ret = tsocket_address_inet_from_strings(state, "ip", NULL, 0, &local_addr);
 197         if (ret != 0) {
 198                 kdc_udp_next_proxy(req);
 199                 return;
 200         }
 201
 202         ret = tsocket_address_inet_from_strings(state, "ip",
 203                                                 state->proxy.ip,
 204                                                 state->port,
 205                                                 &proxy_addr);
 206         if (ret != 0) {
 207                 kdc_udp_next_proxy(req);
 208                 return;
 209         }
 210
 211         /* create a socket for us to work on */
 212         ret = tdgram_inet_udp_socket(local_addr, proxy_addr,
 213                                      state, &state->proxy.dgram);
 214         if (ret != 0) {
 215                 kdc_udp_next_proxy(req);
 216                 return;
 217         }
 218
 219         subreq = tdgram_sendto_send(state,
 220                                     state->ev,
 221                                     state->proxy.dgram,
 222                                     state->in.data,
 223                                     state->in.length,
 224                                     NULL);
 225         if (tevent_req_nomem(subreq, req)) {
 226                 return;
 227         }
 228         tevent_req_set_callback(subreq, kdc_udp_proxy_sendto_done, req);
 229
 230         /* setup to receive the reply from the proxy */
 231         subreq = tdgram_recvfrom_send(state, state->ev, state->proxy.dgram);
 232         if (tevent_req_nomem(subreq, req)) {
 233                 return;
 234         }
 235         tevent_req_set_callback(subreq, kdc_udp_proxy_recvfrom_done, req);
 236         tevent_req_set_endtime(subreq, state->ev,
 237                                timeval_current_ofs(state->kdc->proxy_timeout, 0));
 238
 239         DEBUG(4,("kdc_udp_proxy: proxying request to %s[%s]\n",
 240                  state->proxy.name.name, state->proxy.ip));
 241 }
 242
 243 /*
 244   called when the send of the call to the proxy is complete
 245   this is used to get an errors from the sendto()
 246  */
 247 static void kdc_udp_proxy_sendto_done(struct tevent_req *subreq)
 248 {
 249         struct tevent_req *req =
 250                 tevent_req_callback_data(subreq,
 251                 struct tevent_req);
 252         struct kdc_udp_proxy_state *state =
 253                 tevent_req_data(req,
 254                 struct kdc_udp_proxy_state);
 255         ssize_t ret;
 256         int sys_errno;
 257
 258         ret = tdgram_sendto_recv(subreq, &sys_errno);
 259         TALLOC_FREE(subreq);
 260         if (ret == -1) {
 261                 DEBUG(4,("kdc_udp_proxy: sendto for %s[%s] gave %d : %s\n",
 262                          state->proxy.name.name, state->proxy.ip,
 263                          sys_errno, strerror(sys_errno)));
 264                 kdc_udp_next_proxy(req);
 265         }
 266 }
 267
 268 /*
 269   called when the proxy replies
 270  */
 271 static void kdc_udp_proxy_recvfrom_done(struct tevent_req *subreq)
 272 {
 273         struct tevent_req *req =
 274                 tevent_req_callback_data(subreq,
 275                 struct tevent_req);
 276         struct kdc_udp_proxy_state *state =
 277                 tevent_req_data(req,
 278                 struct kdc_udp_proxy_state);
 279         int sys_errno;
 280         uint8_t *buf;
 281         ssize_t len;
 282
 283         len = tdgram_recvfrom_recv(subreq, &sys_errno,
 284                                    state, &buf, NULL);
 285         TALLOC_FREE(subreq);
 286         if (len == -1) {
 287                 DEBUG(4,("kdc_udp_proxy: reply from %s[%s] gave %d : %s\n",
 288                          state->proxy.name.name, state->proxy.ip,
 289                          sys_errno, strerror(sys_errno)));
 290                 kdc_udp_next_proxy(req);
 291                 return;
 292         }
 293
 294         /*
 295          * Check the reply came from the right IP?
 296          * As we use connected udp sockets, that should not be needed...
 297          */
 298
 299         state->out.length = len;
 300         state->out.data = buf;
 301
 302         tevent_req_done(req);
 303 }
 304
 305 NTSTATUS kdc_udp_proxy_recv(struct tevent_req *req,
 306                             TALLOC_CTX *mem_ctx,
 307                             DATA_BLOB *out)
 308 {
 309         struct kdc_udp_proxy_state *state =
 310                 tevent_req_data(req,
 311                 struct kdc_udp_proxy_state);
 312         NTSTATUS status;
 313
 314         if (tevent_req_is_nterror(req, &status)) {
 315                 tevent_req_received(req);
 316                 return status;
 317         }
 318
 319         out->data = talloc_move(mem_ctx, &state->out.data);
 320         out->length = state->out.length;
 321
 322         tevent_req_received(req);
 323         return NT_STATUS_OK;
 324 }
 325
 326 struct kdc_tcp_proxy_state {
 327         struct tevent_context *ev;
 328         struct kdc_server *kdc;
 329         uint16_t port;
 330         DATA_BLOB in;
 331         uint8_t in_hdr[4];
 332         struct iovec in_iov[2];
 333         DATA_BLOB out;
 334         char **proxy_list;
 335         uint32_t next_proxy;
 336         struct {
 337                 struct nbt_name name;
 338                 const char *ip;
 339                 struct tstream_context *stream;
 340         } proxy;
 341 };
 342
 343 static void kdc_tcp_next_proxy(struct tevent_req *req);
 344
 345 struct tevent_req *kdc_tcp_proxy_send(TALLOC_CTX *mem_ctx,
 346                                       struct tevent_context *ev,
 347                                       struct kdc_server *kdc,
 348                                       uint16_t port,
 349                                       DATA_BLOB in)
 350 {
 351         struct tevent_req *req;
 352         struct kdc_tcp_proxy_state *state;
 353         WERROR werr;
 354
 355         req = tevent_req_create(mem_ctx, &state,
 356                                 struct kdc_tcp_proxy_state);
 357         if (req == NULL) {
 358                 return NULL;
 359         }
 360         state->ev = ev;
 361         state->kdc  = kdc;
 362         state->port = port;
 363         state->in = in;
 364
 365         werr = kdc_proxy_get_writeable_dcs(kdc, state, &state->proxy_list);
 366         if (!W_ERROR_IS_OK(werr)) {
 367                 NTSTATUS status = werror_to_ntstatus(werr);
 368                 tevent_req_nterror(req, status);
 369                 return tevent_req_post(req, ev);
 370         }
 371
 372         RSIVAL(state->in_hdr, 0, state->in.length);
 373         state->in_iov[0].iov_base = (char *)state->in_hdr;
 374         state->in_iov[0].iov_len = 4;
 375         state->in_iov[1].iov_base = (char *)state->in.data;
 376         state->in_iov[1].iov_len = state->in.length;
 377
 378         kdc_tcp_next_proxy(req);
 379         if (!tevent_req_is_in_progress(req)) {
 380                 return tevent_req_post(req, ev);
 381         }
 382
 383         return req;
 384 }
 385
 386 static void kdc_tcp_proxy_resolve_done(struct composite_context *csubreq);
 387
 388 /*
 389   try the next proxy in the list
 390  */
 391 static void kdc_tcp_next_proxy(struct tevent_req *req)
 392 {
 393         struct kdc_tcp_proxy_state *state =
 394                 tevent_req_data(req,
 395                 struct kdc_tcp_proxy_state);
 396         const char *proxy_dnsname = state->proxy_list[state->next_proxy];
 397         struct composite_context *csubreq;
 398
 399         if (proxy_dnsname == NULL) {
 400                 tevent_req_nterror(req, NT_STATUS_NO_LOGON_SERVERS);
 401                 return;
 402         }
 403
 404         state->next_proxy++;
 405
 406         /* make sure we close the socket of the last try */
 407         TALLOC_FREE(state->proxy.stream);
 408         ZERO_STRUCT(state->proxy);
 409
 410         make_nbt_name(&state->proxy.name, proxy_dnsname, 0);
 411
 412         csubreq = resolve_name_ex_send(lpcfg_resolve_context(state->kdc->task->lp_ctx),
 413                                        state,
 414                                        RESOLVE_NAME_FLAG_FORCE_DNS,
 415                                        0,
 416                                        &state->proxy.name,
 417                                        state->ev);
 418         if (tevent_req_nomem(csubreq, req)) {
 419                 return;
 420         }
 421         csubreq->async.fn = kdc_tcp_proxy_resolve_done;
 422         csubreq->async.private_data = req;
 423 }
 424
 425 static void kdc_tcp_proxy_connect_done(struct tevent_req *subreq);
 426
 427 static void kdc_tcp_proxy_resolve_done(struct composite_context *csubreq)
 428 {
 429         struct tevent_req *req =
 430                 talloc_get_type_abort(csubreq->async.private_data,
 431                 struct tevent_req);
 432         struct kdc_tcp_proxy_state *state =
 433                 tevent_req_data(req,
 434                 struct kdc_tcp_proxy_state);
 435         NTSTATUS status;
 436         struct tevent_req *subreq;
 437         struct tsocket_address *local_addr, *proxy_addr;
 438         int ret;
 439
 440         status = resolve_name_recv(csubreq, state, &state->proxy.ip);
 441         if (!NT_STATUS_IS_OK(status)) {
 442                 DEBUG(0,("Unable to resolve proxy[%s] - %s\n",
 443                         state->proxy.name.name, nt_errstr(status)));
 444                 kdc_tcp_next_proxy(req);
 445                 return;
 446         }
 447
 448         /* get an address for us to use locally */
 449         ret = tsocket_address_inet_from_strings(state, "ip", NULL, 0, &local_addr);
 450         if (ret != 0) {
 451                 kdc_tcp_next_proxy(req);
 452                 return;
 453         }
 454
 455         ret = tsocket_address_inet_from_strings(state, "ip",
 456                                                 state->proxy.ip,
 457                                                 state->port,
 458                                                 &proxy_addr);
 459         if (ret != 0) {
 460                 kdc_tcp_next_proxy(req);
 461                 return;
 462         }
 463
 464         subreq = tstream_inet_tcp_connect_send(state, state->ev,
 465                                                local_addr, proxy_addr);
 466         if (tevent_req_nomem(subreq, req)) {
 467                 return;
 468         }
 469         tevent_req_set_callback(subreq, kdc_tcp_proxy_connect_done, req);
 470         tevent_req_set_endtime(subreq, state->ev,
 471                                timeval_current_ofs(state->kdc->proxy_timeout, 0));
 472 }
 473
 474 static void kdc_tcp_proxy_writev_done(struct tevent_req *subreq);
 475 static void kdc_tcp_proxy_read_pdu_done(struct tevent_req *subreq);
 476
 477 static void kdc_tcp_proxy_connect_done(struct tevent_req *subreq)
 478 {
 479         struct tevent_req *req =
 480                 tevent_req_callback_data(subreq,
 481                 struct tevent_req);
 482         struct kdc_tcp_proxy_state *state =
 483                 tevent_req_data(req,
 484                 struct kdc_tcp_proxy_state);
 485         int ret, sys_errno;
 486
 487         ret = tstream_inet_tcp_connect_recv(subreq, &sys_errno,
 488                                             state, &state->proxy.stream, NULL);
 489         TALLOC_FREE(subreq);
 490         if (ret != 0) {
 491                 kdc_tcp_next_proxy(req);
 492                 return;
 493         }
 494
 495         subreq = tstream_writev_send(state,
 496                                      state->ev,
 497                                      state->proxy.stream,
 498                                      state->in_iov, 2);
 499         if (tevent_req_nomem(subreq, req)) {
 500                 return;
 501         }
 502         tevent_req_set_callback(subreq, kdc_tcp_proxy_writev_done, req);
 503
 504         subreq = tstream_read_pdu_blob_send(state,
 505                                             state->ev,
 506                                             state->proxy.stream,
 507                                             4, /* initial_read_size */
 508                                             packet_full_request_u32,
 509                                             req);
 510         if (tevent_req_nomem(subreq, req)) {
 511                 return;
 512         }
 513         tevent_req_set_callback(subreq, kdc_tcp_proxy_read_pdu_done, req);
 514         tevent_req_set_endtime(subreq, state->kdc->task->event_ctx,
 515                                timeval_current_ofs(state->kdc->proxy_timeout, 0));
 516
 517         DEBUG(4,("kdc_tcp_proxy: proxying request to %s[%s]\n",
 518                  state->proxy.name.name, state->proxy.ip));
 519 }
 520
 521 static void kdc_tcp_proxy_writev_done(struct tevent_req *subreq)
 522 {
 523         struct tevent_req *req =
 524                 tevent_req_callback_data(subreq,
 525                 struct tevent_req);
 526         int ret, sys_errno;
 527
 528         ret = tstream_writev_recv(subreq, &sys_errno);
 529         TALLOC_FREE(subreq);
 530         if (ret == -1) {
 531                 kdc_tcp_next_proxy(req);
 532         }
 533 }
 534
 535 static void kdc_tcp_proxy_read_pdu_done(struct tevent_req *subreq)
 536 {
 537         struct tevent_req *req =
 538                 tevent_req_callback_data(subreq,
 539                 struct tevent_req);
 540         struct kdc_tcp_proxy_state *state =
 541                 tevent_req_data(req,
 542                 struct kdc_tcp_proxy_state);
 543         NTSTATUS status;
 544         DATA_BLOB raw;
 545
 546         status = tstream_read_pdu_blob_recv(subreq, state, &raw);
 547         TALLOC_FREE(subreq);
 548         if (!NT_STATUS_IS_OK(status)) {
 549                 kdc_tcp_next_proxy(req);
 550                 return;
 551         }
 552
 553         /*
 554          * raw blob has the length in the first 4 bytes,
 555          * which we do not need here.
 556          */
 557         state->out = data_blob_talloc(state, raw.data + 4, raw.length - 4);
 558         if (state->out.length != raw.length - 4) {
 559                 tevent_req_oom(req);
 560                 return;
 561         }
 562
 563         tevent_req_done(req);
 564 }
 565
 566 NTSTATUS kdc_tcp_proxy_recv(struct tevent_req *req,
 567                             TALLOC_CTX *mem_ctx,
 568                             DATA_BLOB *out)
 569 {
 570         struct kdc_tcp_proxy_state *state =
 571                 tevent_req_data(req,
 572                 struct kdc_tcp_proxy_state);
 573         NTSTATUS status;
 574
 575         if (tevent_req_is_nterror(req, &status)) {
 576                 tevent_req_received(req);
 577                 return status;
 578         }
 579
 580         out->data = talloc_move(mem_ctx, &state->out.data);
 581         out->length = state->out.length;
 582
 583         tevent_req_received(req);
 584         return NT_STATUS_OK;
 585 }