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