source4/rpc_server/dcesrv_auth.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    server side dcerpc authentication code
   5
   6    Copyright (C) Andrew Tridgell 2003
   7    Copyright (C) Stefan (metze) Metzmacher 2004
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "rpc_server/dcerpc_server.h"
  25 #include "rpc_server/dcerpc_server_proto.h"
  26 #include "rpc_server/common/proto.h"
  27 #include "librpc/rpc/dcerpc_proto.h"
  28 #include "librpc/gen_ndr/ndr_dcerpc.h"
  29 #include "auth/credentials/credentials.h"
  30 #include "auth/gensec/gensec.h"
  31 #include "auth/auth.h"
  32 #include "param/param.h"
  33 #include "librpc/rpc/rpc_common.h"
  34
  35 /*
  36   parse any auth information from a dcerpc bind request
  37   return false if we can't handle the auth request for some
  38   reason (in which case we send a bind_nak)
  39 */
  40 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
  41 {
  42         struct cli_credentials *server_credentials = NULL;
  43         struct ncacn_packet *pkt = &call->pkt;
  44         struct dcesrv_connection *dce_conn = call->conn;
  45         struct dcesrv_auth *auth = &dce_conn->auth_state;
  46         NTSTATUS status;
  47
  48         if (pkt->auth_length == 0) {
  49                 enum dcerpc_transport_t transport =
  50                         dcerpc_binding_get_transport(call->conn->endpoint->ep_description);
  51                 const char *auth_type = derpc_transport_string_by_transport(transport);
  52                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
  53                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
  54                 auth->auth_context_id = 0;
  55
  56                 /*
  57                  * Log the authorization to this RPC interface.  This
  58                  * covered ncacn_np pass-through auth, and anonymous
  59                  * DCE/RPC (eg epmapper, netlogon etc)
  60                  */
  61                 log_successful_authz_event(call->conn->remote_address,
  62                                            call->conn->local_address,
  63                                            "DCE/RPC",
  64                                            auth_type,
  65                                            call->conn->auth_state.session_info);
  66
  67                 return true;
  68         }
  69
  70         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.bind.auth_info,
  71                                           &call->in_auth_info,
  72                                           NULL, true);
  73         if (!NT_STATUS_IS_OK(status)) {
  74                 /*
  75                  * Setting DCERPC_AUTH_LEVEL_NONE,
  76                  * gives the caller the reject_reason
  77                  * as auth_context_id.
  78                  *
  79                  * Note: DCERPC_AUTH_LEVEL_NONE == 1
  80                  */
  81                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
  82                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
  83                 auth->auth_context_id =
  84                         DCERPC_BIND_NAK_REASON_PROTOCOL_VERSION_NOT_SUPPORTED;
  85                 return false;
  86         }
  87
  88         switch (call->in_auth_info.auth_level) {
  89         case DCERPC_AUTH_LEVEL_CONNECT:
  90         case DCERPC_AUTH_LEVEL_CALL:
  91         case DCERPC_AUTH_LEVEL_PACKET:
  92         case DCERPC_AUTH_LEVEL_INTEGRITY:
  93         case DCERPC_AUTH_LEVEL_PRIVACY:
  94                 /*
  95                  * We evaluate auth_type only if auth_level was valid
  96                  */
  97                 break;
  98         default:
  99                 /*
 100                  * Setting DCERPC_AUTH_LEVEL_NONE,
 101                  * gives the caller the reject_reason
 102                  * as auth_context_id.
 103                  *
 104                  * Note: DCERPC_AUTH_LEVEL_NONE == 1
 105                  */
 106                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
 107                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
 108                 auth->auth_context_id = DCERPC_BIND_NAK_REASON_NOT_SPECIFIED;
 109                 return false;
 110         }
 111
 112         auth->auth_type = call->in_auth_info.auth_type;
 113         auth->auth_level = call->in_auth_info.auth_level;
 114         auth->auth_context_id = call->in_auth_info.auth_context_id;
 115
 116         server_credentials
 117                 = cli_credentials_init(call);
 118         if (!server_credentials) {
 119                 DEBUG(1, ("Failed to init server credentials\n"));
 120                 return false;
 121         }
 122
 123         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
 124         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
 125         if (!NT_STATUS_IS_OK(status)) {
 126                 DEBUG(1, ("Failed to obtain server credentials: %s\n",
 127                           nt_errstr(status)));
 128                 return false;
 129         }
 130
 131         status = samba_server_gensec_start(dce_conn, call->event_ctx,
 132                                            call->msg_ctx,
 133                                            call->conn->dce_ctx->lp_ctx,
 134                                            server_credentials,
 135                                            NULL,
 136                                            &auth->gensec_security);
 137         if (!NT_STATUS_IS_OK(status)) {
 138                 DEBUG(1, ("Failed to call samba_server_gensec_start %s\n",
 139                           nt_errstr(status)));
 140                 return false;
 141         }
 142
 143         /*
 144          * We have to call this because we set the target_service for
 145          * Kerberos to NULL above, and in any case we wish to log a
 146          * more specific service target.
 147          *
 148          */
 149         status = gensec_set_target_service_description(auth->gensec_security,
 150                                                        "DCE/RPC");
 151         if (!NT_STATUS_IS_OK(status)) {
 152                 DEBUG(1, ("Failed to call gensec_set_target_service_description %s\n",
 153                           nt_errstr(status)));
 154                 return false;
 155         }
 156
 157         if (call->conn->remote_address != NULL) {
 158                 status = gensec_set_remote_address(auth->gensec_security,
 159                                                 call->conn->remote_address);
 160                 if (!NT_STATUS_IS_OK(status)) {
 161                         DEBUG(1, ("Failed to call gensec_set_remote_address() %s\n",
 162                                   nt_errstr(status)));
 163                         return false;
 164                 }
 165         }
 166
 167         if (call->conn->local_address != NULL) {
 168                 status = gensec_set_local_address(auth->gensec_security,
 169                                                   call->conn->local_address);
 170                 if (!NT_STATUS_IS_OK(status)) {
 171                         DEBUG(1, ("Failed to call gensec_set_local_address() %s\n",
 172                                   nt_errstr(status)));
 173                         return false;
 174                 }
 175         }
 176
 177         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_type,
 178                                                auth->auth_level);
 179         if (!NT_STATUS_IS_OK(status)) {
 180                 const char *backend_name =
 181                         gensec_get_name_by_authtype(auth->gensec_security,
 182                                                     auth->auth_type);
 183
 184                 DEBUG(3, ("Failed to start GENSEC mechanism for DCERPC server: "
 185                           "auth_type=%d (%s), auth_level=%d: %s\n",
 186                           (int)auth->auth_type, backend_name,
 187                           (int)auth->auth_level,
 188                           nt_errstr(status)));
 189
 190                 /*
 191                  * Setting DCERPC_AUTH_LEVEL_NONE,
 192                  * gives the caller the reject_reason
 193                  * as auth_context_id.
 194                  *
 195                  * Note: DCERPC_AUTH_LEVEL_NONE == 1
 196                  */
 197                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
 198                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
 199                 if (backend_name != NULL) {
 200                         auth->auth_context_id =
 201                                 DCERPC_BIND_NAK_REASON_INVALID_CHECKSUM;
 202                 } else {
 203                         auth->auth_context_id =
 204                                 DCERPC_BIND_NAK_REASON_INVALID_AUTH_TYPE;
 205                 }
 206                 return false;
 207         }
 208
 209         return true;
 210 }
 211
 212 /*
 213   add any auth information needed in a bind ack, and process the authentication
 214   information found in the bind.
 215 */
 216 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 217 {
 218         struct dcesrv_connection *dce_conn = call->conn;
 219         NTSTATUS status;
 220         bool want_header_signing = false;
 221
 222         dce_conn->allow_alter = true;
 223         dce_conn->allow_auth3 = true;
 224
 225         if (call->pkt.auth_length == 0) {
 226                 dce_conn->auth_state.auth_finished = true;
 227                 dce_conn->allow_request = true;
 228                 return NT_STATUS_OK;
 229         }
 230
 231         /* We can't work without an existing gensec state */
 232         if (!call->conn->auth_state.gensec_security) {
 233                 return NT_STATUS_INTERNAL_ERROR;
 234         }
 235
 236         if (call->pkt.pfc_flags & DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN) {
 237                 dce_conn->auth_state.client_hdr_signing = true;
 238                 want_header_signing = true;
 239         }
 240
 241         if (!lpcfg_parm_bool(call->conn->dce_ctx->lp_ctx, NULL, "dcesrv","header signing", true)) {
 242                 want_header_signing = false;
 243         }
 244
 245         call->_out_auth_info = (struct dcerpc_auth) {
 246                 .auth_type = dce_conn->auth_state.auth_type,
 247                 .auth_level = dce_conn->auth_state.auth_level,
 248                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 249         };
 250         call->out_auth_info = &call->_out_auth_info;
 251
 252         status = gensec_update_ev(dce_conn->auth_state.gensec_security,
 253                                call, call->event_ctx,
 254                                call->in_auth_info.credentials,
 255                                &call->out_auth_info->credentials);
 256
 257         if (NT_STATUS_IS_OK(status)) {
 258                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 259                                              dce_conn,
 260                                              &dce_conn->auth_state.session_info);
 261                 if (!NT_STATUS_IS_OK(status)) {
 262                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 263                         return status;
 264                 }
 265                 dce_conn->auth_state.auth_finished = true;
 266                 dce_conn->allow_request = true;
 267
 268                 if (!gensec_have_feature(dce_conn->auth_state.gensec_security,
 269                                          GENSEC_FEATURE_SIGN_PKT_HEADER))
 270                 {
 271                         want_header_signing = false;
 272                 }
 273
 274                 if (want_header_signing) {
 275                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 276                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 277                         dce_conn->auth_state.hdr_signing = true;
 278                         pkt->pfc_flags |= DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN;
 279                 }
 280
 281                 /* Now that we are authenticated, go back to the generic session key... */
 282                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 283                 return NT_STATUS_OK;
 284         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 285                 if (!gensec_have_feature(dce_conn->auth_state.gensec_security,
 286                                          GENSEC_FEATURE_SIGN_PKT_HEADER))
 287                 {
 288                         want_header_signing = false;
 289                 }
 290
 291                 if (want_header_signing) {
 292                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 293                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 294                         dce_conn->auth_state.hdr_signing = true;
 295                         pkt->pfc_flags |= DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN;
 296                 }
 297
 298                 return NT_STATUS_OK;
 299         } else {
 300                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_ack: %s\n",
 301                           nt_errstr(status)));
 302                 return status;
 303         }
 304 }
 305
 306
 307 /*
 308   process the final stage of a auth request
 309 */
 310 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 311 {
 312         struct ncacn_packet *pkt = &call->pkt;
 313         struct dcesrv_connection *dce_conn = call->conn;
 314         NTSTATUS status;
 315
 316         if (pkt->auth_length == 0) {
 317                 return false;
 318         }
 319
 320         if (dce_conn->auth_state.auth_finished) {
 321                 return false;
 322         }
 323
 324         /* We can't work without an existing gensec state */
 325         if (!dce_conn->auth_state.gensec_security) {
 326                 return false;
 327         }
 328
 329         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.auth3.auth_info,
 330                                           &call->in_auth_info, NULL, true);
 331         if (!NT_STATUS_IS_OK(status)) {
 332                 /*
 333                  * Windows returns DCERPC_NCA_S_FAULT_REMOTE_NO_MEMORY
 334                  * instead of DCERPC_NCA_S_PROTO_ERROR.
 335                  */
 336                 call->fault_code = DCERPC_NCA_S_FAULT_REMOTE_NO_MEMORY;
 337                 return false;
 338         }
 339
 340         if (call->in_auth_info.auth_type != dce_conn->auth_state.auth_type) {
 341                 return false;
 342         }
 343
 344         if (call->in_auth_info.auth_level != dce_conn->auth_state.auth_level) {
 345                 return false;
 346         }
 347
 348         if (call->in_auth_info.auth_context_id != dce_conn->auth_state.auth_context_id) {
 349                 return false;
 350         }
 351
 352         call->_out_auth_info = (struct dcerpc_auth) {
 353                 .auth_type = dce_conn->auth_state.auth_type,
 354                 .auth_level = dce_conn->auth_state.auth_level,
 355                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 356         };
 357         call->out_auth_info = &call->_out_auth_info;
 358
 359         /* Pass the extra data we got from the client down to gensec for processing */
 360         status = gensec_update_ev(dce_conn->auth_state.gensec_security,
 361                                call, call->event_ctx,
 362                                call->in_auth_info.credentials,
 363                                &call->out_auth_info->credentials);
 364         if (NT_STATUS_IS_OK(status)) {
 365                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 366                                              dce_conn,
 367                                              &dce_conn->auth_state.session_info);
 368                 if (!NT_STATUS_IS_OK(status)) {
 369                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 370                         return false;
 371                 }
 372                 dce_conn->auth_state.auth_finished = true;
 373                 dce_conn->allow_request = true;
 374
 375                 /* Now that we are authenticated, go back to the generic session key... */
 376                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 377
 378                 if (call->out_auth_info->credentials.length != 0) {
 379
 380                         DEBUG(4, ("GENSEC produced output token (len=%u) at bind_auth3\n",
 381                                   (unsigned)call->out_auth_info->credentials.length));
 382                         return false;
 383                 }
 384                 return true;
 385         } else {
 386                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_auth3: %s\n",
 387                           nt_errstr(status)));
 388                 return false;
 389         }
 390 }
 391
 392 /*
 393   parse any auth information from a dcerpc alter request
 394   return false if we can't handle the auth request for some
 395   reason (in which case we send a bind_nak (is this true for here?))
 396 */
 397 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 398 {
 399         struct ncacn_packet *pkt = &call->pkt;
 400         struct dcesrv_connection *dce_conn = call->conn;
 401         NTSTATUS status;
 402
 403         /* on a pure interface change there is no auth blob */
 404         if (pkt->auth_length == 0) {
 405                 if (!dce_conn->auth_state.auth_finished) {
 406                         return false;
 407                 }
 408                 return true;
 409         }
 410
 411         if (dce_conn->auth_state.auth_finished) {
 412                 call->fault_code = DCERPC_FAULT_ACCESS_DENIED;
 413                 return false;
 414         }
 415
 416         /* We can't work without an existing gensec state */
 417         if (!dce_conn->auth_state.gensec_security) {
 418                 return false;
 419         }
 420
 421         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.alter.auth_info,
 422                                           &call->in_auth_info, NULL, true);
 423         if (!NT_STATUS_IS_OK(status)) {
 424                 call->fault_code = DCERPC_NCA_S_PROTO_ERROR;
 425                 return false;
 426         }
 427
 428         if (call->in_auth_info.auth_type == DCERPC_AUTH_TYPE_NONE) {
 429                 call->fault_code = DCERPC_FAULT_ACCESS_DENIED;
 430                 return false;
 431         }
 432
 433         if (call->in_auth_info.auth_type != dce_conn->auth_state.auth_type) {
 434                 return false;
 435         }
 436
 437         if (call->in_auth_info.auth_level != dce_conn->auth_state.auth_level) {
 438                 return false;
 439         }
 440
 441         if (call->in_auth_info.auth_context_id != dce_conn->auth_state.auth_context_id) {
 442                 return false;
 443         }
 444
 445         return true;
 446 }
 447
 448 /*
 449   add any auth information needed in a alter ack, and process the authentication
 450   information found in the alter.
 451 */
 452 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 453 {
 454         struct dcesrv_connection *dce_conn = call->conn;
 455         NTSTATUS status;
 456
 457         /* on a pure interface change there is no auth_info structure
 458            setup */
 459         if (call->pkt.auth_length == 0) {
 460                 return NT_STATUS_OK;
 461         }
 462
 463         if (!call->conn->auth_state.gensec_security) {
 464                 return NT_STATUS_INTERNAL_ERROR;
 465         }
 466
 467         call->_out_auth_info = (struct dcerpc_auth) {
 468                 .auth_type = dce_conn->auth_state.auth_type,
 469                 .auth_level = dce_conn->auth_state.auth_level,
 470                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 471         };
 472         call->out_auth_info = &call->_out_auth_info;
 473
 474         status = gensec_update_ev(dce_conn->auth_state.gensec_security,
 475                                call, call->event_ctx,
 476                                call->in_auth_info.credentials,
 477                                &call->out_auth_info->credentials);
 478
 479         if (NT_STATUS_IS_OK(status)) {
 480                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 481                                              dce_conn,
 482                                              &dce_conn->auth_state.session_info);
 483                 if (!NT_STATUS_IS_OK(status)) {
 484                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 485                         return status;
 486                 }
 487                 dce_conn->auth_state.auth_finished = true;
 488                 dce_conn->allow_request = true;
 489
 490                 /* Now that we are authenticated, got back to the generic session key... */
 491                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 492                 return NT_STATUS_OK;
 493         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 494                 return NT_STATUS_OK;
 495         }
 496
 497         DEBUG(4, ("GENSEC mech rejected the incoming authentication at auth alter_ack: %s\n",
 498                   nt_errstr(status)));
 499         return status;
 500 }
 501
 502 /*
 503   check credentials on a packet
 504 */
 505 bool dcesrv_auth_pkt_pull(struct dcesrv_call_state *call,
 506                           DATA_BLOB *full_packet,
 507                           uint8_t required_flags,
 508                           uint8_t optional_flags,
 509                           uint8_t payload_offset,
 510                           DATA_BLOB *payload_and_verifier)
 511 {
 512         struct ncacn_packet *pkt = &call->pkt;
 513         struct dcesrv_connection *dce_conn = call->conn;
 514         const struct dcerpc_auth tmp_auth = {
 515                 .auth_type = dce_conn->auth_state.auth_type,
 516                 .auth_level = dce_conn->auth_state.auth_level,
 517                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 518         };
 519         NTSTATUS status;
 520
 521         if (!dce_conn->allow_request) {
 522                 call->fault_code = DCERPC_NCA_S_PROTO_ERROR;
 523                 return false;
 524         }
 525
 526         if (dce_conn->auth_state.auth_invalid) {
 527                 return false;
 528         }
 529
 530         status = dcerpc_ncacn_pull_pkt_auth(&tmp_auth,
 531                                             dce_conn->auth_state.gensec_security,
 532                                             call,
 533                                             pkt->ptype,
 534                                             required_flags,
 535                                             optional_flags,
 536                                             payload_offset,
 537                                             payload_and_verifier,
 538                                             full_packet,
 539                                             pkt);
 540         if (NT_STATUS_EQUAL(status, NT_STATUS_RPC_PROTOCOL_ERROR)) {
 541                 call->fault_code = DCERPC_NCA_S_PROTO_ERROR;
 542                 return false;
 543         }
 544         if (NT_STATUS_EQUAL(status, NT_STATUS_RPC_UNSUPPORTED_AUTHN_LEVEL)) {
 545                 call->fault_code = DCERPC_NCA_S_UNSUPPORTED_AUTHN_LEVEL;
 546                 return false;
 547         }
 548         if (NT_STATUS_EQUAL(status, NT_STATUS_RPC_SEC_PKG_ERROR)) {
 549                 call->fault_code = DCERPC_FAULT_SEC_PKG_ERROR;
 550                 return false;
 551         }
 552         if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 553                 call->fault_code = DCERPC_FAULT_ACCESS_DENIED;
 554                 return false;
 555         }
 556         if (!NT_STATUS_IS_OK(status)) {
 557                 return false;
 558         }
 559
 560         return true;
 561 }
 562
 563 /*
 564    push a signed or sealed dcerpc request packet into a blob
 565 */
 566 bool dcesrv_auth_pkt_push(struct dcesrv_call_state *call,
 567                           DATA_BLOB *blob, size_t sig_size,
 568                           uint8_t payload_offset,
 569                           const DATA_BLOB *payload,
 570                           const struct ncacn_packet *pkt)
 571 {
 572         struct dcesrv_connection *dce_conn = call->conn;
 573         const struct dcerpc_auth tmp_auth = {
 574                 .auth_type = dce_conn->auth_state.auth_type,
 575                 .auth_level = dce_conn->auth_state.auth_level,
 576                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 577         };
 578         NTSTATUS status;
 579
 580         status = dcerpc_ncacn_push_pkt_auth(&tmp_auth,
 581                                             dce_conn->auth_state.gensec_security,
 582                                             call, blob, sig_size,
 583                                             payload_offset,
 584                                             payload,
 585                                             pkt);
 586         return NT_STATUS_IS_OK(status);
 587 }