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