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;
  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         uint32_t auth_length;
  48
  49         if (pkt->u.bind.auth_info.length == 0) {
  50                 dce_conn->auth_state.auth_info = NULL;
  51                 return true;
  52         }
  53
  54         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  55         if (!dce_conn->auth_state.auth_info) {
  56                 return false;
  57         }
  58
  59         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.bind.auth_info,
  60                                           dce_conn->auth_state.auth_info,
  61                                           &auth_length, false);
  62         server_credentials
  63                 = cli_credentials_init(call);
  64         if (!server_credentials) {
  65                 DEBUG(1, ("Failed to init server credentials\n"));
  66                 return false;
  67         }
  68
  69         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  70         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  71         if (!NT_STATUS_IS_OK(status)) {
  72                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  73                 talloc_free(server_credentials);
  74                 server_credentials = NULL;
  75         }
  76
  77         status = samba_server_gensec_start(dce_conn, call->event_ctx,
  78                                            call->msg_ctx,
  79                                            call->conn->dce_ctx->lp_ctx,
  80                                            server_credentials,
  81                                            NULL,
  82                                            &auth->gensec_security);
  83         if (!NT_STATUS_IS_OK(status)) {
  84                 DEBUG(1, ("Failed to call samba_server_gensec_start %s\n",
  85                           nt_errstr(status)));
  86                 return false;
  87         }
  88
  89         if (call->conn->remote_address != NULL) {
  90                 status = gensec_set_remote_address(auth->gensec_security,
  91                                                 call->conn->remote_address);
  92                 if (!NT_STATUS_IS_OK(status)) {
  93                         DEBUG(1, ("Failed to call gensec_set_remote_address() %s\n",
  94                                   nt_errstr(status)));
  95                         return false;
  96                 }
  97         }
  98
  99         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
 100                                                auth->auth_info->auth_level);
 101         if (!NT_STATUS_IS_OK(status)) {
 102                 DEBUG(3, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
 103                           (int)auth->auth_info->auth_type,
 104                           (int)auth->auth_info->auth_level,
 105                           nt_errstr(status)));
 106                 return false;
 107         }
 108
 109         return true;
 110 }
 111
 112 /*
 113   add any auth information needed in a bind ack, and process the authentication
 114   information found in the bind.
 115 */
 116 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 117 {
 118         struct dcesrv_connection *dce_conn = call->conn;
 119         NTSTATUS status;
 120         bool want_header_signing = false;
 121
 122         if (!call->conn->auth_state.gensec_security) {
 123                 return NT_STATUS_OK;
 124         }
 125
 126         if (call->pkt.pfc_flags & DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN) {
 127                 dce_conn->auth_state.client_hdr_signing = true;
 128                 want_header_signing = true;
 129         }
 130
 131         if (!lpcfg_parm_bool(call->conn->dce_ctx->lp_ctx, NULL, "dcesrv","header signing", true)) {
 132                 want_header_signing = false;
 133         }
 134
 135         status = gensec_update_ev(dce_conn->auth_state.gensec_security,
 136                                call, call->event_ctx,
 137                                dce_conn->auth_state.auth_info->credentials,
 138                                &dce_conn->auth_state.auth_info->credentials);
 139
 140         if (NT_STATUS_IS_OK(status)) {
 141                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 142                                              dce_conn,
 143                                              &dce_conn->auth_state.session_info);
 144                 if (!NT_STATUS_IS_OK(status)) {
 145                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 146                         return status;
 147                 }
 148
 149                 if (!gensec_have_feature(dce_conn->auth_state.gensec_security,
 150                                          GENSEC_FEATURE_SIGN_PKT_HEADER))
 151                 {
 152                         want_header_signing = false;
 153                 }
 154
 155                 if (want_header_signing) {
 156                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 157                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 158                         dce_conn->auth_state.hdr_signing = true;
 159                         pkt->pfc_flags |= DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN;
 160                 }
 161
 162                 /* Now that we are authenticated, go back to the generic session key... */
 163                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 164                 return NT_STATUS_OK;
 165         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 166                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 167                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 168
 169                 if (!gensec_have_feature(dce_conn->auth_state.gensec_security,
 170                                          GENSEC_FEATURE_SIGN_PKT_HEADER))
 171                 {
 172                         want_header_signing = false;
 173                 }
 174
 175                 if (want_header_signing) {
 176                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 177                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 178                         dce_conn->auth_state.hdr_signing = true;
 179                         pkt->pfc_flags |= DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN;
 180                 }
 181
 182                 return NT_STATUS_OK;
 183         } else {
 184                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_ack: %s\n",
 185                           nt_errstr(status)));
 186                 return status;
 187         }
 188 }
 189
 190
 191 /*
 192   process the final stage of a auth request
 193 */
 194 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 195 {
 196         struct ncacn_packet *pkt = &call->pkt;
 197         struct dcesrv_connection *dce_conn = call->conn;
 198         NTSTATUS status;
 199         uint32_t auth_length;
 200
 201         /* We can't work without an existing gensec state, and an new blob to feed it */
 202         if (!dce_conn->auth_state.auth_info ||
 203             !dce_conn->auth_state.gensec_security ||
 204             pkt->u.auth3.auth_info.length == 0) {
 205                 return false;
 206         }
 207
 208         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.auth3.auth_info,
 209                                           dce_conn->auth_state.auth_info, &auth_length, true);
 210         if (!NT_STATUS_IS_OK(status)) {
 211                 return false;
 212         }
 213
 214         /* Pass the extra data we got from the client down to gensec for processing */
 215         status = gensec_update_ev(dce_conn->auth_state.gensec_security,
 216                                call, call->event_ctx,
 217                                dce_conn->auth_state.auth_info->credentials,
 218                                &dce_conn->auth_state.auth_info->credentials);
 219         if (NT_STATUS_IS_OK(status)) {
 220                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 221                                              dce_conn,
 222                                              &dce_conn->auth_state.session_info);
 223                 if (!NT_STATUS_IS_OK(status)) {
 224                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 225                         return false;
 226                 }
 227                 /* Now that we are authenticated, go back to the generic session key... */
 228                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 229                 return true;
 230         } else {
 231                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_auth3: %s\n",
 232                           nt_errstr(status)));
 233                 return false;
 234         }
 235 }
 236
 237 /*
 238   parse any auth information from a dcerpc alter request
 239   return false if we can't handle the auth request for some
 240   reason (in which case we send a bind_nak (is this true for here?))
 241 */
 242 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 243 {
 244         struct ncacn_packet *pkt = &call->pkt;
 245         struct dcesrv_connection *dce_conn = call->conn;
 246         NTSTATUS status;
 247         uint32_t auth_length;
 248
 249         /* on a pure interface change there is no auth blob */
 250         if (pkt->u.alter.auth_info.length == 0) {
 251                 return true;
 252         }
 253
 254         /* We can't work without an existing gensec state */
 255         if (!dce_conn->auth_state.gensec_security) {
 256                 return false;
 257         }
 258
 259         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 260         if (!dce_conn->auth_state.auth_info) {
 261                 return false;
 262         }
 263
 264         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.alter.auth_info,
 265                                           dce_conn->auth_state.auth_info,
 266                                           &auth_length, true);
 267         if (!NT_STATUS_IS_OK(status)) {
 268                 return false;
 269         }
 270
 271         return true;
 272 }
 273
 274 /*
 275   add any auth information needed in a alter ack, and process the authentication
 276   information found in the alter.
 277 */
 278 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 279 {
 280         struct dcesrv_connection *dce_conn = call->conn;
 281         NTSTATUS status;
 282
 283         /* on a pure interface change there is no auth_info structure
 284            setup */
 285         if (!call->conn->auth_state.auth_info ||
 286             dce_conn->auth_state.auth_info->credentials.length == 0) {
 287                 return NT_STATUS_OK;
 288         }
 289
 290         if (!call->conn->auth_state.gensec_security) {
 291                 return NT_STATUS_INVALID_PARAMETER;
 292         }
 293
 294         status = gensec_update_ev(dce_conn->auth_state.gensec_security,
 295                                call, call->event_ctx,
 296                                dce_conn->auth_state.auth_info->credentials,
 297                                &dce_conn->auth_state.auth_info->credentials);
 298
 299         if (NT_STATUS_IS_OK(status)) {
 300                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 301                                              dce_conn,
 302                                              &dce_conn->auth_state.session_info);
 303                 if (!NT_STATUS_IS_OK(status)) {
 304                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 305                         return status;
 306                 }
 307
 308                 /* Now that we are authenticated, got back to the generic session key... */
 309                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 310                 return NT_STATUS_OK;
 311         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 312                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 313                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 314                 return NT_STATUS_OK;
 315         }
 316
 317         DEBUG(4, ("GENSEC mech rejected the incoming authentication at auth alter_ack: %s\n",
 318                   nt_errstr(status)));
 319         return status;
 320 }
 321
 322 /*
 323   check credentials on a request
 324 */
 325 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 326 {
 327         struct ncacn_packet *pkt = &call->pkt;
 328         struct dcesrv_connection *dce_conn = call->conn;
 329         struct dcerpc_auth auth;
 330         NTSTATUS status;
 331         uint32_t auth_length;
 332         size_t hdr_size = DCERPC_REQUEST_LENGTH;
 333
 334         if (!dce_conn->auth_state.auth_info ||
 335             !dce_conn->auth_state.gensec_security) {
 336                 if (pkt->auth_length != 0) {
 337                         return false;
 338                 }
 339                 return true;
 340         }
 341
 342         if (pkt->pfc_flags & DCERPC_PFC_FLAG_OBJECT_UUID) {
 343                 hdr_size += 16;
 344         }
 345
 346         switch (dce_conn->auth_state.auth_info->auth_level) {
 347         case DCERPC_AUTH_LEVEL_PRIVACY:
 348         case DCERPC_AUTH_LEVEL_INTEGRITY:
 349                 break;
 350
 351         case DCERPC_AUTH_LEVEL_CONNECT:
 352                 if (pkt->auth_length != 0) {
 353                         break;
 354                 }
 355                 return true;
 356         case DCERPC_AUTH_LEVEL_NONE:
 357                 if (pkt->auth_length != 0) {
 358                         return false;
 359                 }
 360                 return true;
 361
 362         default:
 363                 return false;
 364         }
 365
 366         status = dcerpc_pull_auth_trailer(pkt, call,
 367                                           &pkt->u.request.stub_and_verifier,
 368                                           &auth, &auth_length, false);
 369         if (!NT_STATUS_IS_OK(status)) {
 370                 return false;
 371         }
 372
 373         if (auth.auth_type != dce_conn->auth_state.auth_info->auth_type) {
 374                 return false;
 375         }
 376
 377         if (auth.auth_level != dce_conn->auth_state.auth_info->auth_level) {
 378                 return false;
 379         }
 380
 381         if (auth.auth_context_id != dce_conn->auth_state.auth_info->auth_context_id) {
 382                 return false;
 383         }
 384
 385         pkt->u.request.stub_and_verifier.length -= auth_length;
 386
 387         /* check signature or unseal the packet */
 388         switch (dce_conn->auth_state.auth_info->auth_level) {
 389         case DCERPC_AUTH_LEVEL_PRIVACY:
 390                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 391                                               full_packet->data + hdr_size,
 392                                               pkt->u.request.stub_and_verifier.length,
 393                                               full_packet->data,
 394                                               full_packet->length-auth.credentials.length,
 395                                               &auth.credentials);
 396                 memcpy(pkt->u.request.stub_and_verifier.data,
 397                        full_packet->data + hdr_size,
 398                        pkt->u.request.stub_and_verifier.length);
 399                 break;
 400
 401         case DCERPC_AUTH_LEVEL_INTEGRITY:
 402                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 403                                              pkt->u.request.stub_and_verifier.data,
 404                                              pkt->u.request.stub_and_verifier.length,
 405                                              full_packet->data,
 406                                              full_packet->length-auth.credentials.length,
 407                                              &auth.credentials);
 408                 break;
 409
 410         case DCERPC_AUTH_LEVEL_CONNECT:
 411                 /* for now we ignore possible signatures here */
 412                 status = NT_STATUS_OK;
 413                 break;
 414
 415         default:
 416                 status = NT_STATUS_INVALID_LEVEL;
 417                 break;
 418         }
 419
 420         /* remove the indicated amount of padding */
 421         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 422                 return false;
 423         }
 424         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 425
 426         return NT_STATUS_IS_OK(status);
 427 }
 428
 429
 430 /*
 431    push a signed or sealed dcerpc request packet into a blob
 432 */
 433 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 434                           DATA_BLOB *blob, size_t sig_size,
 435                           struct ncacn_packet *pkt)
 436 {
 437         struct dcesrv_connection *dce_conn = call->conn;
 438         NTSTATUS status;
 439         enum ndr_err_code ndr_err;
 440         struct ndr_push *ndr;
 441         uint32_t payload_length;
 442         DATA_BLOB creds2;
 443
 444         /* non-signed packets are simple */
 445         if (sig_size == 0) {
 446                 status = ncacn_push_auth(blob, call, pkt, NULL);
 447                 return NT_STATUS_IS_OK(status);
 448         }
 449
 450         switch (dce_conn->auth_state.auth_info->auth_level) {
 451         case DCERPC_AUTH_LEVEL_PRIVACY:
 452         case DCERPC_AUTH_LEVEL_INTEGRITY:
 453                 break;
 454
 455         case DCERPC_AUTH_LEVEL_CONNECT:
 456                 /*
 457                  * TODO: let the gensec mech decide if it wants to generate a
 458                  *       signature that might be needed for schannel...
 459                  */
 460                 status = ncacn_push_auth(blob, call, pkt, NULL);
 461                 return NT_STATUS_IS_OK(status);
 462
 463         case DCERPC_AUTH_LEVEL_NONE:
 464                 status = ncacn_push_auth(blob, call, pkt, NULL);
 465                 return NT_STATUS_IS_OK(status);
 466
 467         default:
 468                 return false;
 469         }
 470
 471         ndr = ndr_push_init_ctx(call);
 472         if (!ndr) {
 473                 return false;
 474         }
 475
 476         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 477                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 478         }
 479
 480         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 481         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 482                 return false;
 483         }
 484
 485         /* pad to 16 byte multiple in the payload portion of the
 486            packet. This matches what w2k3 does. Note that we can't use
 487            ndr_push_align() as that is relative to the start of the
 488            whole packet, whereas w2k8 wants it relative to the start
 489            of the stub */
 490         dce_conn->auth_state.auth_info->auth_pad_length =
 491                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 492         ndr_err = ndr_push_zero(ndr,
 493                                 dce_conn->auth_state.auth_info->auth_pad_length);
 494         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 495                 return false;
 496         }
 497
 498         payload_length = pkt->u.response.stub_and_verifier.length +
 499                 dce_conn->auth_state.auth_info->auth_pad_length;
 500
 501         /* we start without signature, it will appended later */
 502         dce_conn->auth_state.auth_info->credentials = data_blob(NULL, 0);
 503
 504         /* add the auth verifier */
 505         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 506                                        dce_conn->auth_state.auth_info);
 507         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 508                 return false;
 509         }
 510
 511         /* extract the whole packet as a blob */
 512         *blob = ndr_push_blob(ndr);
 513
 514         /*
 515          * Setup the frag and auth length in the packet buffer.
 516          * This is needed if the GENSEC mech does AEAD signing
 517          * of the packet headers. The signature itself will be
 518          * appended later.
 519          */
 520         dcerpc_set_frag_length(blob, blob->length + sig_size);
 521         dcerpc_set_auth_length(blob, sig_size);
 522
 523         /* sign or seal the packet */
 524         switch (dce_conn->auth_state.auth_info->auth_level) {
 525         case DCERPC_AUTH_LEVEL_PRIVACY:
 526                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 527                                             call,
 528                                             ndr->data + DCERPC_REQUEST_LENGTH,
 529                                             payload_length,
 530                                             blob->data,
 531                                             blob->length,
 532                                             &creds2);
 533                 break;
 534
 535         case DCERPC_AUTH_LEVEL_INTEGRITY:
 536                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 537                                             call,
 538                                             ndr->data + DCERPC_REQUEST_LENGTH,
 539                                             payload_length,
 540                                             blob->data,
 541                                             blob->length,
 542                                             &creds2);
 543                 break;
 544
 545         default:
 546                 status = NT_STATUS_INVALID_LEVEL;
 547                 break;
 548         }
 549
 550         if (!NT_STATUS_IS_OK(status)) {
 551                 return false;
 552         }
 553
 554         if (creds2.length != sig_size) {
 555                 DEBUG(3,("dcesrv_auth_response: creds2.length[%u] != sig_size[%u] pad[%u] stub[%u]\n",
 556                          (unsigned)creds2.length, (uint32_t)sig_size,
 557                          (unsigned)dce_conn->auth_state.auth_info->auth_pad_length,
 558                          (unsigned)pkt->u.response.stub_and_verifier.length));
 559                 dcerpc_set_frag_length(blob, blob->length + creds2.length);
 560                 dcerpc_set_auth_length(blob, creds2.length);
 561         }
 562
 563         if (!data_blob_append(call, blob, creds2.data, creds2.length)) {
 564                 status = NT_STATUS_NO_MEMORY;
 565                 return false;
 566         }
 567         data_blob_free(&creds2);
 568
 569         return true;
 570 }