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