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 "librpc/rpc/dcerpc_proto.h"
  27 #include "librpc/gen_ndr/ndr_dcerpc.h"
  28 #include "auth/credentials/credentials.h"
  29 #include "auth/gensec/gensec.h"
  30 #include "param/param.h"
  31
  32 /*
  33   parse any auth information from a dcerpc bind request
  34   return false if we can't handle the auth request for some
  35   reason (in which case we send a bind_nak)
  36 */
  37 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
  38 {
  39         struct cli_credentials *server_credentials;
  40         struct ncacn_packet *pkt = &call->pkt;
  41         struct dcesrv_connection *dce_conn = call->conn;
  42         struct dcesrv_auth *auth = &dce_conn->auth_state;
  43         NTSTATUS status;
  44         enum ndr_err_code ndr_err;
  45
  46         if (pkt->u.bind.auth_info.length == 0) {
  47                 dce_conn->auth_state.auth_info = NULL;
  48                 return true;
  49         }
  50
  51         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  52         if (!dce_conn->auth_state.auth_info) {
  53                 return false;
  54         }
  55
  56         ndr_err = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
  57                                        call, NULL,
  58                                        dce_conn->auth_state.auth_info,
  59                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
  60         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  61                 return false;
  62         }
  63
  64         status = gensec_server_start(dce_conn, call->event_ctx,
  65                                      lp_gensec_settings(dce_conn, call->conn->dce_ctx->lp_ctx),
  66                                      call->msg_ctx, &auth->gensec_security);
  67         if (!NT_STATUS_IS_OK(status)) {
  68                 DEBUG(1, ("Failed to start GENSEC for DCERPC server: %s\n", nt_errstr(status)));
  69                 return false;
  70         }
  71
  72         server_credentials
  73                 = cli_credentials_init(call);
  74         if (!server_credentials) {
  75                 DEBUG(1, ("Failed to init server credentials\n"));
  76                 return false;
  77         }
  78
  79         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  80         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  81         if (!NT_STATUS_IS_OK(status)) {
  82                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  83                 talloc_free(server_credentials);
  84                 server_credentials = NULL;
  85         }
  86
  87         gensec_set_credentials(auth->gensec_security, server_credentials);
  88
  89         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  90                                                auth->auth_info->auth_level);
  91
  92         if (!NT_STATUS_IS_OK(status)) {
  93                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
  94                           (int)auth->auth_info->auth_type,
  95                           (int)auth->auth_info->auth_level,
  96                           nt_errstr(status)));
  97                 return false;
  98         }
  99
 100         if (call->conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
 101                 gensec_want_feature(auth->gensec_security, GENSEC_FEATURE_SIGN_PKT_HEADER);
 102         }
 103
 104         return true;
 105 }
 106
 107 /*
 108   add any auth information needed in a bind ack, and process the authentication
 109   information found in the bind.
 110 */
 111 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 112 {
 113         struct dcesrv_connection *dce_conn = call->conn;
 114         NTSTATUS status;
 115
 116         if (!call->conn->auth_state.gensec_security) {
 117                 return NT_STATUS_OK;
 118         }
 119
 120         status = gensec_update(dce_conn->auth_state.gensec_security,
 121                                call,
 122                                dce_conn->auth_state.auth_info->credentials,
 123                                &dce_conn->auth_state.auth_info->credentials);
 124
 125         if (NT_STATUS_IS_OK(status)) {
 126                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 127                                              &dce_conn->auth_state.session_info);
 128                 if (!NT_STATUS_IS_OK(status)) {
 129                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 130                         return status;
 131                 }
 132
 133                 if (dce_conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
 134                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 135                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 136                 }
 137
 138                 /* Now that we are authenticated, go back to the generic session key... */
 139                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 140                 return NT_STATUS_OK;
 141         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 142                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 143                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 144                 return NT_STATUS_OK;
 145         } else {
 146                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 147                 return status;
 148         }
 149 }
 150
 151
 152 /*
 153   process the final stage of a auth request
 154 */
 155 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 156 {
 157         struct ncacn_packet *pkt = &call->pkt;
 158         struct dcesrv_connection *dce_conn = call->conn;
 159         NTSTATUS status;
 160         enum ndr_err_code ndr_err;
 161
 162         /* We can't work without an existing gensec state, and an new blob to feed it */
 163         if (!dce_conn->auth_state.auth_info ||
 164             !dce_conn->auth_state.gensec_security ||
 165             pkt->u.auth3.auth_info.length == 0) {
 166                 return false;
 167         }
 168
 169         ndr_err = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 170                                        call, NULL,
 171                                        dce_conn->auth_state.auth_info,
 172                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 173         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 174                 return false;
 175         }
 176
 177         /* Pass the extra data we got from the client down to gensec for processing */
 178         status = gensec_update(dce_conn->auth_state.gensec_security,
 179                                call,
 180                                dce_conn->auth_state.auth_info->credentials,
 181                                &dce_conn->auth_state.auth_info->credentials);
 182         if (NT_STATUS_IS_OK(status)) {
 183                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 184                                              &dce_conn->auth_state.session_info);
 185                 if (!NT_STATUS_IS_OK(status)) {
 186                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 187                         return false;
 188                 }
 189                 /* Now that we are authenticated, go back to the generic session key... */
 190                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 191                 return true;
 192         } else {
 193                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 194                           nt_errstr(status)));
 195                 return false;
 196         }
 197
 198         return true;
 199 }
 200
 201 /*
 202   parse any auth information from a dcerpc alter request
 203   return false if we can't handle the auth request for some
 204   reason (in which case we send a bind_nak (is this true for here?))
 205 */
 206 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 207 {
 208         struct ncacn_packet *pkt = &call->pkt;
 209         struct dcesrv_connection *dce_conn = call->conn;
 210         enum ndr_err_code ndr_err;
 211
 212         /* on a pure interface change there is no auth blob */
 213         if (pkt->u.alter.auth_info.length == 0) {
 214                 return true;
 215         }
 216
 217         /* We can't work without an existing gensec state */
 218         if (!dce_conn->auth_state.gensec_security) {
 219                 return false;
 220         }
 221
 222         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 223         if (!dce_conn->auth_state.auth_info) {
 224                 return false;
 225         }
 226
 227         ndr_err = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 228                                        call, NULL,
 229                                        dce_conn->auth_state.auth_info,
 230                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 231         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 232                 return false;
 233         }
 234
 235         return true;
 236 }
 237
 238 /*
 239   add any auth information needed in a alter ack, and process the authentication
 240   information found in the alter.
 241 */
 242 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 243 {
 244         struct dcesrv_connection *dce_conn = call->conn;
 245         NTSTATUS status;
 246
 247         /* on a pure interface change there is no auth_info structure
 248            setup */
 249         if (!call->conn->auth_state.auth_info ||
 250             dce_conn->auth_state.auth_info->credentials.length == 0) {
 251                 return NT_STATUS_OK;
 252         }
 253
 254         if (!call->conn->auth_state.gensec_security) {
 255                 return NT_STATUS_INVALID_PARAMETER;
 256         }
 257
 258         status = gensec_update(dce_conn->auth_state.gensec_security,
 259                                call,
 260                                dce_conn->auth_state.auth_info->credentials,
 261                                &dce_conn->auth_state.auth_info->credentials);
 262
 263         if (NT_STATUS_IS_OK(status)) {
 264                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 265                                              &dce_conn->auth_state.session_info);
 266                 if (!NT_STATUS_IS_OK(status)) {
 267                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 268                         return status;
 269                 }
 270
 271                 /* Now that we are authenticated, got back to the generic session key... */
 272                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 273                 return NT_STATUS_OK;
 274         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 275                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 276                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 277                 return NT_STATUS_OK;
 278         }
 279
 280         DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 281         return status;
 282 }
 283
 284 /*
 285   check credentials on a request
 286 */
 287 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 288 {
 289         struct ncacn_packet *pkt = &call->pkt;
 290         struct dcesrv_connection *dce_conn = call->conn;
 291         DATA_BLOB auth_blob;
 292         struct dcerpc_auth auth;
 293         struct ndr_pull *ndr;
 294         NTSTATUS status;
 295         enum ndr_err_code ndr_err;
 296         size_t hdr_size = DCERPC_REQUEST_LENGTH;
 297
 298         if (!dce_conn->auth_state.auth_info ||
 299             !dce_conn->auth_state.gensec_security) {
 300                 return true;
 301         }
 302
 303         switch (dce_conn->auth_state.auth_info->auth_level) {
 304         case DCERPC_AUTH_LEVEL_PRIVACY:
 305         case DCERPC_AUTH_LEVEL_INTEGRITY:
 306                 break;
 307
 308         case DCERPC_AUTH_LEVEL_CONNECT:
 309                 if (pkt->auth_length != 0) {
 310                         break;
 311                 }
 312                 return true;
 313         case DCERPC_AUTH_LEVEL_NONE:
 314                 if (pkt->auth_length != 0) {
 315                         return false;
 316                 }
 317                 return true;
 318
 319         default:
 320                 return false;
 321         }
 322
 323         auth_blob.length = 8 + pkt->auth_length;
 324
 325         /* check for a valid length */
 326         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 327                 return false;
 328         }
 329
 330         auth_blob.data =
 331                 pkt->u.request.stub_and_verifier.data +
 332                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 333         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 334
 335         /* pull the auth structure */
 336         ndr = ndr_pull_init_blob(&auth_blob, call, lp_iconv_convenience(call->conn->dce_ctx->lp_ctx));
 337         if (!ndr) {
 338                 return false;
 339         }
 340
 341         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 342                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 343         }
 344
 345         if (pkt->pfc_flags & DCERPC_PFC_FLAG_OBJECT_UUID) {
 346                 ndr->flags |= LIBNDR_FLAG_OBJECT_PRESENT;
 347                 hdr_size += 16;
 348         }
 349
 350         ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 351         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 352                 talloc_free(ndr);
 353                 return false;
 354         }
 355
 356         /* check signature or unseal the packet */
 357         switch (dce_conn->auth_state.auth_info->auth_level) {
 358         case DCERPC_AUTH_LEVEL_PRIVACY:
 359                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 360                                               call,
 361                                               full_packet->data + hdr_size,
 362                                               pkt->u.request.stub_and_verifier.length,
 363                                               full_packet->data,
 364                                               full_packet->length-auth.credentials.length,
 365                                               &auth.credentials);
 366                 memcpy(pkt->u.request.stub_and_verifier.data,
 367                        full_packet->data + hdr_size,
 368                        pkt->u.request.stub_and_verifier.length);
 369                 break;
 370
 371         case DCERPC_AUTH_LEVEL_INTEGRITY:
 372                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 373                                              call,
 374                                              pkt->u.request.stub_and_verifier.data,
 375                                              pkt->u.request.stub_and_verifier.length,
 376                                              full_packet->data,
 377                                              full_packet->length-auth.credentials.length,
 378                                              &auth.credentials);
 379                 break;
 380
 381         case DCERPC_AUTH_LEVEL_CONNECT:
 382                 /* for now we ignore possible signatures here */
 383                 status = NT_STATUS_OK;
 384                 break;
 385
 386         default:
 387                 status = NT_STATUS_INVALID_LEVEL;
 388                 break;
 389         }
 390
 391         /* remove the indicated amount of padding */
 392         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 393                 talloc_free(ndr);
 394                 return false;
 395         }
 396         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 397         talloc_free(ndr);
 398
 399         return NT_STATUS_IS_OK(status);
 400 }
 401
 402
 403 /*
 404    push a signed or sealed dcerpc request packet into a blob
 405 */
 406 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 407                           DATA_BLOB *blob, size_t sig_size,
 408                           struct ncacn_packet *pkt)
 409 {
 410         struct dcesrv_connection *dce_conn = call->conn;
 411         NTSTATUS status;
 412         enum ndr_err_code ndr_err;
 413         struct ndr_push *ndr;
 414         uint32_t payload_length;
 415         DATA_BLOB creds2;
 416
 417         /* non-signed packets are simple */
 418         if (sig_size == 0) {
 419                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 420                 return NT_STATUS_IS_OK(status);
 421         }
 422
 423         switch (dce_conn->auth_state.auth_info->auth_level) {
 424         case DCERPC_AUTH_LEVEL_PRIVACY:
 425         case DCERPC_AUTH_LEVEL_INTEGRITY:
 426                 break;
 427
 428         case DCERPC_AUTH_LEVEL_CONNECT:
 429                 /*
 430                  * TODO: let the gensec mech decide if it wants to generate a signature
 431                  *       that might be needed for schannel...
 432                  */
 433                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 434                 return NT_STATUS_IS_OK(status);
 435
 436         case DCERPC_AUTH_LEVEL_NONE:
 437                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 438                 return NT_STATUS_IS_OK(status);
 439
 440         default:
 441                 return false;
 442         }
 443
 444         ndr = ndr_push_init_ctx(call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx));
 445         if (!ndr) {
 446                 return false;
 447         }
 448
 449         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 450                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 451         }
 452
 453         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 454         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 455                 return false;
 456         }
 457
 458         /* pad to 16 byte multiple, match win2k3 */
 459         dce_conn->auth_state.auth_info->auth_pad_length =
 460                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 461         ndr_err = ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 462         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 463                 return false;
 464         }
 465
 466         payload_length = pkt->u.response.stub_and_verifier.length +
 467                 dce_conn->auth_state.auth_info->auth_pad_length;
 468
 469         /* we start without signature, it will appended later */
 470         dce_conn->auth_state.auth_info->credentials = data_blob(NULL, 0);
 471
 472         /* add the auth verifier */
 473         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 474                                       dce_conn->auth_state.auth_info);
 475         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 476                 return false;
 477         }
 478
 479         /* extract the whole packet as a blob */
 480         *blob = ndr_push_blob(ndr);
 481
 482         /*
 483          * Setup the frag and auth length in the packet buffer.
 484          * This is needed if the GENSEC mech does AEAD signing
 485          * of the packet headers. The signature itself will be
 486          * appended later.
 487          */
 488         dcerpc_set_frag_length(blob, blob->length + sig_size);
 489         dcerpc_set_auth_length(blob, sig_size);
 490
 491         /* sign or seal the packet */
 492         switch (dce_conn->auth_state.auth_info->auth_level) {
 493         case DCERPC_AUTH_LEVEL_PRIVACY:
 494                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 495                                             call,
 496                                             ndr->data + DCERPC_REQUEST_LENGTH,
 497                                             payload_length,
 498                                             blob->data,
 499                                             blob->length,
 500                                             &creds2);
 501                 break;
 502
 503         case DCERPC_AUTH_LEVEL_INTEGRITY:
 504                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 505                                             call,
 506                                             ndr->data + DCERPC_REQUEST_LENGTH,
 507                                             payload_length,
 508                                             blob->data,
 509                                             blob->length,
 510                                             &creds2);
 511                 break;
 512
 513         default:
 514                 status = NT_STATUS_INVALID_LEVEL;
 515                 break;
 516         }
 517
 518         if (NT_STATUS_IS_OK(status)) {
 519                 if (creds2.length != sig_size) {
 520                         DEBUG(0,("dcesrv_auth_response: creds2.length[%u] != sig_size[%u] pad[%u] stub[%u]\n",
 521                                 creds2.length, (uint32_t)sig_size,
 522                                 dce_conn->auth_state.auth_info->auth_pad_length,
 523                                 pkt->u.response.stub_and_verifier.length));
 524                         data_blob_free(&creds2);
 525                         status = NT_STATUS_INTERNAL_ERROR;
 526                 }
 527         }
 528
 529         if (NT_STATUS_IS_OK(status)) {
 530                 if (!data_blob_append(call, blob, creds2.data, creds2.length)) {
 531                         status = NT_STATUS_NO_MEMORY;
 532                 }
 533                 data_blob_free(&creds2);
 534         }
 535
 536         if (!NT_STATUS_IS_OK(status)) {
 537                 return false;
 538         }
 539
 540         return true;
 541 }