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         bool want_header_signing = false;
  47         NTSTATUS status;
  48
  49         if (pkt->auth_length == 0) {
  50                 enum dcerpc_transport_t transport =
  51                         dcerpc_binding_get_transport(call->conn->endpoint->ep_description);
  52                 const char *auth_type = derpc_transport_string_by_transport(transport);
  53                 const char *transport_protection = AUTHZ_TRANSPORT_PROTECTION_NONE;
  54                 if (transport == NCACN_NP) {
  55                         transport_protection = AUTHZ_TRANSPORT_PROTECTION_SMB;
  56                 }
  57                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
  58                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
  59                 auth->auth_context_id = 0;
  60
  61                 /*
  62                  * Log the authorization to this RPC interface.  This
  63                  * covered ncacn_np pass-through auth, and anonymous
  64                  * DCE/RPC (eg epmapper, netlogon etc)
  65                  */
  66                 log_successful_authz_event(call->conn->msg_ctx,
  67                                            call->conn->dce_ctx->lp_ctx,
  68                                            call->conn->remote_address,
  69                                            call->conn->local_address,
  70                                            "DCE/RPC",
  71                                            auth_type,
  72                                            transport_protection,
  73                                            call->conn->auth_state.session_info);
  74
  75                 return true;
  76         }
  77
  78         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.bind.auth_info,
  79                                           &call->in_auth_info,
  80                                           NULL, true);
  81         if (!NT_STATUS_IS_OK(status)) {
  82                 /*
  83                  * Setting DCERPC_AUTH_LEVEL_NONE,
  84                  * gives the caller the reject_reason
  85                  * as auth_context_id.
  86                  *
  87                  * Note: DCERPC_AUTH_LEVEL_NONE == 1
  88                  */
  89                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
  90                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
  91                 auth->auth_context_id =
  92                         DCERPC_BIND_NAK_REASON_PROTOCOL_VERSION_NOT_SUPPORTED;
  93                 return false;
  94         }
  95
  96         switch (call->in_auth_info.auth_level) {
  97         case DCERPC_AUTH_LEVEL_CONNECT:
  98         case DCERPC_AUTH_LEVEL_CALL:
  99         case DCERPC_AUTH_LEVEL_PACKET:
 100         case DCERPC_AUTH_LEVEL_INTEGRITY:
 101         case DCERPC_AUTH_LEVEL_PRIVACY:
 102                 /*
 103                  * We evaluate auth_type only if auth_level was valid
 104                  */
 105                 break;
 106         default:
 107                 /*
 108                  * Setting DCERPC_AUTH_LEVEL_NONE,
 109                  * gives the caller the reject_reason
 110                  * as auth_context_id.
 111                  *
 112                  * Note: DCERPC_AUTH_LEVEL_NONE == 1
 113                  */
 114                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
 115                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
 116                 auth->auth_context_id = DCERPC_BIND_NAK_REASON_NOT_SPECIFIED;
 117                 return false;
 118         }
 119
 120         auth->auth_type = call->in_auth_info.auth_type;
 121         auth->auth_level = call->in_auth_info.auth_level;
 122         auth->auth_context_id = call->in_auth_info.auth_context_id;
 123
 124         server_credentials
 125                 = cli_credentials_init(call);
 126         if (!server_credentials) {
 127                 DEBUG(1, ("Failed to init server credentials\n"));
 128                 return false;
 129         }
 130
 131         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
 132         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
 133         if (!NT_STATUS_IS_OK(status)) {
 134                 DEBUG(1, ("Failed to obtain server credentials: %s\n",
 135                           nt_errstr(status)));
 136                 return false;
 137         }
 138
 139         status = samba_server_gensec_start(dce_conn, call->event_ctx,
 140                                            call->msg_ctx,
 141                                            call->conn->dce_ctx->lp_ctx,
 142                                            server_credentials,
 143                                            NULL,
 144                                            &auth->gensec_security);
 145         if (!NT_STATUS_IS_OK(status)) {
 146                 DEBUG(1, ("Failed to call samba_server_gensec_start %s\n",
 147                           nt_errstr(status)));
 148                 return false;
 149         }
 150
 151         /*
 152          * We have to call this because we set the target_service for
 153          * Kerberos to NULL above, and in any case we wish to log a
 154          * more specific service target.
 155          *
 156          */
 157         status = gensec_set_target_service_description(auth->gensec_security,
 158                                                        "DCE/RPC");
 159         if (!NT_STATUS_IS_OK(status)) {
 160                 DEBUG(1, ("Failed to call gensec_set_target_service_description %s\n",
 161                           nt_errstr(status)));
 162                 return false;
 163         }
 164
 165         if (call->conn->remote_address != NULL) {
 166                 status = gensec_set_remote_address(auth->gensec_security,
 167                                                 call->conn->remote_address);
 168                 if (!NT_STATUS_IS_OK(status)) {
 169                         DEBUG(1, ("Failed to call gensec_set_remote_address() %s\n",
 170                                   nt_errstr(status)));
 171                         return false;
 172                 }
 173         }
 174
 175         if (call->conn->local_address != NULL) {
 176                 status = gensec_set_local_address(auth->gensec_security,
 177                                                   call->conn->local_address);
 178                 if (!NT_STATUS_IS_OK(status)) {
 179                         DEBUG(1, ("Failed to call gensec_set_local_address() %s\n",
 180                                   nt_errstr(status)));
 181                         return false;
 182                 }
 183         }
 184
 185         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_type,
 186                                                auth->auth_level);
 187         if (!NT_STATUS_IS_OK(status)) {
 188                 const char *backend_name =
 189                         gensec_get_name_by_authtype(auth->gensec_security,
 190                                                     auth->auth_type);
 191
 192                 DEBUG(3, ("Failed to start GENSEC mechanism for DCERPC server: "
 193                           "auth_type=%d (%s), auth_level=%d: %s\n",
 194                           (int)auth->auth_type, backend_name,
 195                           (int)auth->auth_level,
 196                           nt_errstr(status)));
 197
 198                 /*
 199                  * Setting DCERPC_AUTH_LEVEL_NONE,
 200                  * gives the caller the reject_reason
 201                  * as auth_context_id.
 202                  *
 203                  * Note: DCERPC_AUTH_LEVEL_NONE == 1
 204                  */
 205                 auth->auth_type = DCERPC_AUTH_TYPE_NONE;
 206                 auth->auth_level = DCERPC_AUTH_LEVEL_NONE;
 207                 if (backend_name != NULL) {
 208                         auth->auth_context_id =
 209                                 DCERPC_BIND_NAK_REASON_INVALID_CHECKSUM;
 210                 } else {
 211                         auth->auth_context_id =
 212                                 DCERPC_BIND_NAK_REASON_INVALID_AUTH_TYPE;
 213                 }
 214                 return false;
 215         }
 216
 217         if (call->pkt.pfc_flags & DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN) {
 218                 auth->client_hdr_signing = true;
 219                 want_header_signing = true;
 220         }
 221
 222         if (want_header_signing) {
 223                 want_header_signing = gensec_have_feature(auth->gensec_security,
 224                                                 GENSEC_FEATURE_SIGN_PKT_HEADER);
 225         }
 226
 227         if (want_header_signing) {
 228                 want_header_signing = lpcfg_parm_bool(dce_conn->dce_ctx->lp_ctx,
 229                                                       NULL,
 230                                                       "dcesrv",
 231                                                       "header signing",
 232                                                       true);
 233         }
 234
 235         if (want_header_signing) {
 236                 gensec_want_feature(auth->gensec_security,
 237                                     GENSEC_FEATURE_SIGN_PKT_HEADER);
 238                 auth->hdr_signing = true;
 239         }
 240
 241         return true;
 242 }
 243
 244 NTSTATUS dcesrv_auth_complete(struct dcesrv_call_state *call, NTSTATUS status)
 245 {
 246         struct dcesrv_connection *dce_conn = call->conn;
 247         const char *pdu = "<unknown>";
 248
 249         switch (call->pkt.ptype) {
 250         case DCERPC_PKT_BIND:
 251                 pdu = "BIND";
 252                 break;
 253         case DCERPC_PKT_ALTER:
 254                 pdu = "ALTER";
 255                 break;
 256         case DCERPC_PKT_AUTH3:
 257                 pdu = "AUTH3";
 258                 if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 259                         DEBUG(4, ("GENSEC not finished at at %s\n", pdu));
 260                         return NT_STATUS_RPC_SEC_PKG_ERROR;
 261                 }
 262                 break;
 263         default:
 264                 return NT_STATUS_INTERNAL_ERROR;
 265         }
 266
 267         if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 268                 return NT_STATUS_OK;
 269         }
 270
 271         if (!NT_STATUS_IS_OK(status)) {
 272                 DEBUG(4, ("GENSEC mech rejected the incoming authentication "
 273                           "at %s: %s\n", pdu, nt_errstr(status)));
 274                 return status;
 275         }
 276
 277         status = gensec_session_info(dce_conn->auth_state.gensec_security,
 278                                      dce_conn,
 279                                      &dce_conn->auth_state.session_info);
 280         if (!NT_STATUS_IS_OK(status)) {
 281                 DEBUG(1, ("Failed to establish session_info: %s\n",
 282                           nt_errstr(status)));
 283                 return status;
 284         }
 285         dce_conn->auth_state.auth_finished = true;
 286         dce_conn->allow_request = true;
 287
 288         /* Now that we are authenticated, go back to the generic session key... */
 289         dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 290
 291         if (call->pkt.ptype != DCERPC_PKT_AUTH3) {
 292                 return NT_STATUS_OK;
 293         }
 294
 295         if (call->out_auth_info->credentials.length != 0) {
 296                 DEBUG(4, ("GENSEC produced output token (len=%zu) at %s\n",
 297                           call->out_auth_info->credentials.length, pdu));
 298                 return NT_STATUS_RPC_SEC_PKG_ERROR;
 299         }
 300
 301         return NT_STATUS_OK;
 302 }
 303
 304 /*
 305   add any auth information needed in a bind ack, and process the authentication
 306   information found in the bind.
 307 */
 308 NTSTATUS dcesrv_auth_prepare_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 309 {
 310         struct dcesrv_connection *dce_conn = call->conn;
 311
 312         dce_conn->allow_alter = true;
 313         dce_conn->allow_auth3 = true;
 314
 315         if (call->pkt.auth_length == 0) {
 316                 dce_conn->auth_state.auth_finished = true;
 317                 dce_conn->allow_request = true;
 318                 return NT_STATUS_OK;
 319         }
 320
 321         /* We can't work without an existing gensec state */
 322         if (!call->conn->auth_state.gensec_security) {
 323                 return NT_STATUS_INTERNAL_ERROR;
 324         }
 325
 326         if (dce_conn->auth_state.hdr_signing) {
 327                 pkt->pfc_flags |= DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN;
 328         }
 329
 330         call->_out_auth_info = (struct dcerpc_auth) {
 331                 .auth_type = dce_conn->auth_state.auth_type,
 332                 .auth_level = dce_conn->auth_state.auth_level,
 333                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 334         };
 335         call->out_auth_info = &call->_out_auth_info;
 336
 337         return NT_STATUS_OK;
 338 }
 339
 340 /*
 341   process the final stage of a auth request
 342 */
 343 bool dcesrv_auth_prepare_auth3(struct dcesrv_call_state *call)
 344 {
 345         struct ncacn_packet *pkt = &call->pkt;
 346         struct dcesrv_connection *dce_conn = call->conn;
 347         NTSTATUS status;
 348
 349         if (pkt->auth_length == 0) {
 350                 return false;
 351         }
 352
 353         if (dce_conn->auth_state.auth_finished) {
 354                 return false;
 355         }
 356
 357         /* We can't work without an existing gensec state */
 358         if (!dce_conn->auth_state.gensec_security) {
 359                 return false;
 360         }
 361
 362         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.auth3.auth_info,
 363                                           &call->in_auth_info, NULL, true);
 364         if (!NT_STATUS_IS_OK(status)) {
 365                 /*
 366                  * Windows returns DCERPC_NCA_S_FAULT_REMOTE_NO_MEMORY
 367                  * instead of DCERPC_NCA_S_PROTO_ERROR.
 368                  */
 369                 call->fault_code = DCERPC_NCA_S_FAULT_REMOTE_NO_MEMORY;
 370                 return false;
 371         }
 372
 373         if (call->in_auth_info.auth_type != dce_conn->auth_state.auth_type) {
 374                 return false;
 375         }
 376
 377         if (call->in_auth_info.auth_level != dce_conn->auth_state.auth_level) {
 378                 return false;
 379         }
 380
 381         if (call->in_auth_info.auth_context_id != dce_conn->auth_state.auth_context_id) {
 382                 return false;
 383         }
 384
 385         call->_out_auth_info = (struct dcerpc_auth) {
 386                 .auth_type = dce_conn->auth_state.auth_type,
 387                 .auth_level = dce_conn->auth_state.auth_level,
 388                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 389         };
 390         call->out_auth_info = &call->_out_auth_info;
 391
 392         return true;
 393 }
 394
 395 /*
 396   parse any auth information from a dcerpc alter request
 397   return false if we can't handle the auth request for some
 398   reason (in which case we send a bind_nak (is this true for here?))
 399 */
 400 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 401 {
 402         struct ncacn_packet *pkt = &call->pkt;
 403         struct dcesrv_connection *dce_conn = call->conn;
 404         NTSTATUS status;
 405
 406         /* on a pure interface change there is no auth blob */
 407         if (pkt->auth_length == 0) {
 408                 if (!dce_conn->auth_state.auth_finished) {
 409                         return false;
 410                 }
 411                 return true;
 412         }
 413
 414         if (dce_conn->auth_state.auth_finished) {
 415                 call->fault_code = DCERPC_FAULT_ACCESS_DENIED;
 416                 return false;
 417         }
 418
 419         /* We can't work without an existing gensec state */
 420         if (!dce_conn->auth_state.gensec_security) {
 421                 return false;
 422         }
 423
 424         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.alter.auth_info,
 425                                           &call->in_auth_info, NULL, true);
 426         if (!NT_STATUS_IS_OK(status)) {
 427                 call->fault_code = DCERPC_NCA_S_PROTO_ERROR;
 428                 return false;
 429         }
 430
 431         if (call->in_auth_info.auth_type == DCERPC_AUTH_TYPE_NONE) {
 432                 call->fault_code = DCERPC_FAULT_ACCESS_DENIED;
 433                 return false;
 434         }
 435
 436         if (call->in_auth_info.auth_type != dce_conn->auth_state.auth_type) {
 437                 return false;
 438         }
 439
 440         if (call->in_auth_info.auth_level != dce_conn->auth_state.auth_level) {
 441                 return false;
 442         }
 443
 444         if (call->in_auth_info.auth_context_id != dce_conn->auth_state.auth_context_id) {
 445                 return false;
 446         }
 447
 448         return true;
 449 }
 450
 451 /*
 452   add any auth information needed in a alter ack, and process the authentication
 453   information found in the alter.
 454 */
 455 NTSTATUS dcesrv_auth_prepare_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 456 {
 457         struct dcesrv_connection *dce_conn = call->conn;
 458
 459         /* on a pure interface change there is no auth_info structure
 460            setup */
 461         if (call->pkt.auth_length == 0) {
 462                 return NT_STATUS_OK;
 463         }
 464
 465         if (!call->conn->auth_state.gensec_security) {
 466                 return NT_STATUS_INTERNAL_ERROR;
 467         }
 468
 469         call->_out_auth_info = (struct dcerpc_auth) {
 470                 .auth_type = dce_conn->auth_state.auth_type,
 471                 .auth_level = dce_conn->auth_state.auth_level,
 472                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 473         };
 474         call->out_auth_info = &call->_out_auth_info;
 475
 476         return NT_STATUS_OK;
 477 }
 478
 479 /*
 480   check credentials on a packet
 481 */
 482 bool dcesrv_auth_pkt_pull(struct dcesrv_call_state *call,
 483                           DATA_BLOB *full_packet,
 484                           uint8_t required_flags,
 485                           uint8_t optional_flags,
 486                           uint8_t payload_offset,
 487                           DATA_BLOB *payload_and_verifier)
 488 {
 489         struct ncacn_packet *pkt = &call->pkt;
 490         struct dcesrv_connection *dce_conn = call->conn;
 491         const struct dcerpc_auth tmp_auth = {
 492                 .auth_type = dce_conn->auth_state.auth_type,
 493                 .auth_level = dce_conn->auth_state.auth_level,
 494                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 495         };
 496         NTSTATUS status;
 497
 498         if (!dce_conn->allow_request) {
 499                 call->fault_code = DCERPC_NCA_S_PROTO_ERROR;
 500                 return false;
 501         }
 502
 503         if (dce_conn->auth_state.auth_invalid) {
 504                 return false;
 505         }
 506
 507         status = dcerpc_ncacn_pull_pkt_auth(&tmp_auth,
 508                                             dce_conn->auth_state.gensec_security,
 509                                             call,
 510                                             pkt->ptype,
 511                                             required_flags,
 512                                             optional_flags,
 513                                             payload_offset,
 514                                             payload_and_verifier,
 515                                             full_packet,
 516                                             pkt);
 517         if (NT_STATUS_EQUAL(status, NT_STATUS_RPC_PROTOCOL_ERROR)) {
 518                 call->fault_code = DCERPC_NCA_S_PROTO_ERROR;
 519                 return false;
 520         }
 521         if (NT_STATUS_EQUAL(status, NT_STATUS_RPC_UNSUPPORTED_AUTHN_LEVEL)) {
 522                 call->fault_code = DCERPC_NCA_S_UNSUPPORTED_AUTHN_LEVEL;
 523                 return false;
 524         }
 525         if (NT_STATUS_EQUAL(status, NT_STATUS_RPC_SEC_PKG_ERROR)) {
 526                 call->fault_code = DCERPC_FAULT_SEC_PKG_ERROR;
 527                 return false;
 528         }
 529         if (NT_STATUS_EQUAL(status, NT_STATUS_ACCESS_DENIED)) {
 530                 call->fault_code = DCERPC_FAULT_ACCESS_DENIED;
 531                 return false;
 532         }
 533         if (!NT_STATUS_IS_OK(status)) {
 534                 return false;
 535         }
 536
 537         return true;
 538 }
 539
 540 /*
 541    push a signed or sealed dcerpc request packet into a blob
 542 */
 543 bool dcesrv_auth_pkt_push(struct dcesrv_call_state *call,
 544                           DATA_BLOB *blob, size_t sig_size,
 545                           uint8_t payload_offset,
 546                           const DATA_BLOB *payload,
 547                           const struct ncacn_packet *pkt)
 548 {
 549         struct dcesrv_connection *dce_conn = call->conn;
 550         const struct dcerpc_auth tmp_auth = {
 551                 .auth_type = dce_conn->auth_state.auth_type,
 552                 .auth_level = dce_conn->auth_state.auth_level,
 553                 .auth_context_id = dce_conn->auth_state.auth_context_id,
 554         };
 555         NTSTATUS status;
 556
 557         status = dcerpc_ncacn_push_pkt_auth(&tmp_auth,
 558                                             dce_conn->auth_state.gensec_security,
 559                                             call, blob, sig_size,
 560                                             payload_offset,
 561                                             payload,
 562                                             pkt);
 563         return NT_STATUS_IS_OK(status);
 564 }