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, call->conn->dce_ctx->lp_ctx, call->msg_ctx, &auth->gensec_security);
  65         if (!NT_STATUS_IS_OK(status)) {
  66                 DEBUG(1, ("Failed to start GENSEC for DCERPC server: %s\n", nt_errstr(status)));
  67                 return false;
  68         }
  69
  70         server_credentials
  71                 = cli_credentials_init(call);
  72         if (!server_credentials) {
  73                 DEBUG(1, ("Failed to init server credentials\n"));
  74                 return false;
  75         }
  76
  77         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  78         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  79         if (!NT_STATUS_IS_OK(status)) {
  80                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  81                 talloc_free(server_credentials);
  82                 server_credentials = NULL;
  83         }
  84
  85         gensec_set_credentials(auth->gensec_security, server_credentials);
  86
  87         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  88                                                auth->auth_info->auth_level);
  89
  90         if (!NT_STATUS_IS_OK(status)) {
  91                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
  92                           (int)auth->auth_info->auth_type,
  93                           (int)auth->auth_info->auth_level,
  94                           nt_errstr(status)));
  95                 return false;
  96         }
  97
  98         return true;
  99 }
 100
 101 /*
 102   add any auth information needed in a bind ack, and process the authentication
 103   information found in the bind.
 104 */
 105 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 106 {
 107         struct dcesrv_connection *dce_conn = call->conn;
 108         NTSTATUS status;
 109
 110         if (!call->conn->auth_state.gensec_security) {
 111                 return NT_STATUS_OK;
 112         }
 113
 114         status = gensec_update(dce_conn->auth_state.gensec_security,
 115                                call,
 116                                dce_conn->auth_state.auth_info->credentials,
 117                                &dce_conn->auth_state.auth_info->credentials);
 118
 119         if (NT_STATUS_IS_OK(status)) {
 120                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 121                                              &dce_conn->auth_state.session_info);
 122                 if (!NT_STATUS_IS_OK(status)) {
 123                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 124                         return status;
 125                 }
 126
 127                 if (dce_conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
 128                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 129                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 130                 }
 131
 132                 /* Now that we are authenticated, go back to the generic session key... */
 133                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 134                 return NT_STATUS_OK;
 135         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 136                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 137                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 138                 return NT_STATUS_OK;
 139         } else {
 140                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 141                 return status;
 142         }
 143 }
 144
 145
 146 /*
 147   process the final stage of a auth request
 148 */
 149 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 150 {
 151         struct ncacn_packet *pkt = &call->pkt;
 152         struct dcesrv_connection *dce_conn = call->conn;
 153         NTSTATUS status;
 154         enum ndr_err_code ndr_err;
 155
 156         /* We can't work without an existing gensec state, and an new blob to feed it */
 157         if (!dce_conn->auth_state.auth_info ||
 158             !dce_conn->auth_state.gensec_security ||
 159             pkt->u.auth3.auth_info.length == 0) {
 160                 return false;
 161         }
 162
 163         ndr_err = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 164                                        call, NULL,
 165                                        dce_conn->auth_state.auth_info,
 166                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 167         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 168                 return false;
 169         }
 170
 171         /* Pass the extra data we got from the client down to gensec for processing */
 172         status = gensec_update(dce_conn->auth_state.gensec_security,
 173                                call,
 174                                dce_conn->auth_state.auth_info->credentials,
 175                                &dce_conn->auth_state.auth_info->credentials);
 176         if (NT_STATUS_IS_OK(status)) {
 177                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 178                                              &dce_conn->auth_state.session_info);
 179                 if (!NT_STATUS_IS_OK(status)) {
 180                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 181                         return false;
 182                 }
 183                 /* Now that we are authenticated, go back to the generic session key... */
 184                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 185                 return true;
 186         } else {
 187                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 188                           nt_errstr(status)));
 189                 return false;
 190         }
 191
 192         return true;
 193 }
 194
 195 /*
 196   parse any auth information from a dcerpc alter request
 197   return false if we can't handle the auth request for some
 198   reason (in which case we send a bind_nak (is this true for here?))
 199 */
 200 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 201 {
 202         struct ncacn_packet *pkt = &call->pkt;
 203         struct dcesrv_connection *dce_conn = call->conn;
 204         enum ndr_err_code ndr_err;
 205
 206         /* on a pure interface change there is no auth blob */
 207         if (pkt->u.alter.auth_info.length == 0) {
 208                 return true;
 209         }
 210
 211         /* We can't work without an existing gensec state */
 212         if (!dce_conn->auth_state.gensec_security) {
 213                 return false;
 214         }
 215
 216         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 217         if (!dce_conn->auth_state.auth_info) {
 218                 return false;
 219         }
 220
 221         ndr_err = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 222                                        call, NULL,
 223                                        dce_conn->auth_state.auth_info,
 224                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 225         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 226                 return false;
 227         }
 228
 229         return true;
 230 }
 231
 232 /*
 233   add any auth information needed in a alter ack, and process the authentication
 234   information found in the alter.
 235 */
 236 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 237 {
 238         struct dcesrv_connection *dce_conn = call->conn;
 239         NTSTATUS status;
 240
 241         /* on a pure interface change there is no auth_info structure
 242            setup */
 243         if (!call->conn->auth_state.auth_info ||
 244             dce_conn->auth_state.auth_info->credentials.length == 0) {
 245                 return NT_STATUS_OK;
 246         }
 247
 248         if (!call->conn->auth_state.gensec_security) {
 249                 return NT_STATUS_INVALID_PARAMETER;
 250         }
 251
 252         status = gensec_update(dce_conn->auth_state.gensec_security,
 253                                call,
 254                                dce_conn->auth_state.auth_info->credentials,
 255                                &dce_conn->auth_state.auth_info->credentials);
 256
 257         if (NT_STATUS_IS_OK(status)) {
 258                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 259                                              &dce_conn->auth_state.session_info);
 260                 if (!NT_STATUS_IS_OK(status)) {
 261                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 262                         return status;
 263                 }
 264
 265                 /* Now that we are authenticated, got back to the generic session key... */
 266                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 267                 return NT_STATUS_OK;
 268         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 269                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 270                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 271                 return NT_STATUS_OK;
 272         }
 273
 274         DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 275         return status;
 276 }
 277
 278 /*
 279   generate a CONNECT level verifier
 280 */
 281 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 282 {
 283         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 284         if (blob->data == NULL) {
 285                 return NT_STATUS_NO_MEMORY;
 286         }
 287         SIVAL(blob->data, 0, 1);
 288         memset(blob->data+4, 0, 12);
 289         return NT_STATUS_OK;
 290 }
 291
 292 /*
 293   generate a CONNECT level verifier
 294 */
 295 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 296 {
 297         if (blob->length != 16 ||
 298             IVAL(blob->data, 0) != 1) {
 299                 return NT_STATUS_ACCESS_DENIED;
 300         }
 301         return NT_STATUS_OK;
 302 }
 303
 304
 305 /*
 306   check credentials on a request
 307 */
 308 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 309 {
 310         struct ncacn_packet *pkt = &call->pkt;
 311         struct dcesrv_connection *dce_conn = call->conn;
 312         DATA_BLOB auth_blob;
 313         struct dcerpc_auth auth;
 314         struct ndr_pull *ndr;
 315         NTSTATUS status;
 316         enum ndr_err_code ndr_err;
 317
 318         if (!dce_conn->auth_state.auth_info ||
 319             !dce_conn->auth_state.gensec_security) {
 320                 return true;
 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         ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 346         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 347                 talloc_free(ndr);
 348                 return false;
 349         }
 350
 351         /* check signature or unseal the packet */
 352         switch (dce_conn->auth_state.auth_info->auth_level) {
 353         case DCERPC_AUTH_LEVEL_PRIVACY:
 354                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 355                                               call,
 356                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 357                                               pkt->u.request.stub_and_verifier.length,
 358                                               full_packet->data,
 359                                               full_packet->length-auth.credentials.length,
 360                                               &auth.credentials);
 361                 memcpy(pkt->u.request.stub_and_verifier.data,
 362                        full_packet->data + DCERPC_REQUEST_LENGTH,
 363                        pkt->u.request.stub_and_verifier.length);
 364                 break;
 365
 366         case DCERPC_AUTH_LEVEL_INTEGRITY:
 367                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 368                                              call,
 369                                              pkt->u.request.stub_and_verifier.data,
 370                                              pkt->u.request.stub_and_verifier.length,
 371                                              full_packet->data,
 372                                              full_packet->length-auth.credentials.length,
 373                                              &auth.credentials);
 374                 break;
 375
 376         case DCERPC_AUTH_LEVEL_CONNECT:
 377                 status = dcesrv_check_connect_verifier(&auth.credentials);
 378                 break;
 379
 380         default:
 381                 status = NT_STATUS_INVALID_LEVEL;
 382                 break;
 383         }
 384
 385         /* remove the indicated amount of padding */
 386         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 387                 talloc_free(ndr);
 388                 return false;
 389         }
 390         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 391         talloc_free(ndr);
 392
 393         return NT_STATUS_IS_OK(status);
 394 }
 395
 396
 397 /*
 398    push a signed or sealed dcerpc request packet into a blob
 399 */
 400 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 401                           DATA_BLOB *blob, size_t sig_size,
 402                           struct ncacn_packet *pkt)
 403 {
 404         struct dcesrv_connection *dce_conn = call->conn;
 405         NTSTATUS status;
 406         enum ndr_err_code ndr_err;
 407         struct ndr_push *ndr;
 408         uint32_t payload_length;
 409         DATA_BLOB creds2;
 410
 411         /* non-signed packets are simple */
 412         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 413                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 414                 return NT_STATUS_IS_OK(status);
 415         }
 416
 417         ndr = ndr_push_init_ctx(call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx));
 418         if (!ndr) {
 419                 return false;
 420         }
 421
 422         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 423                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 424         }
 425
 426         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 427         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 428                 return false;
 429         }
 430
 431         /* pad to 16 byte multiple, match win2k3 */
 432         dce_conn->auth_state.auth_info->auth_pad_length =
 433                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 434         ndr_err = ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 435         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 436                 return false;
 437         }
 438
 439         payload_length = pkt->u.response.stub_and_verifier.length +
 440                 dce_conn->auth_state.auth_info->auth_pad_length;
 441
 442         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 443                 status = dcesrv_connect_verifier(call,
 444                                                  &dce_conn->auth_state.auth_info->credentials);
 445                 if (!NT_STATUS_IS_OK(status)) {
 446                         return false;
 447                 }
 448         } else {
 449
 450                 /* We hope this length is accruate.  If must be if the
 451                  * GENSEC mech does AEAD signing of the packet
 452                  * headers */
 453                 dce_conn->auth_state.auth_info->credentials
 454                         = data_blob_talloc(call, NULL, sig_size);
 455                 data_blob_clear(&dce_conn->auth_state.auth_info->credentials);
 456         }
 457
 458         /* add the auth verifier */
 459         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 460                                       dce_conn->auth_state.auth_info);
 461         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 462                 return false;
 463         }
 464
 465         /* extract the whole packet as a blob */
 466         *blob = ndr_push_blob(ndr);
 467
 468         /* fill in the fragment length and auth_length, we can't fill
 469            in these earlier as we don't know the signature length (it
 470            could be variable length) */
 471         dcerpc_set_frag_length(blob, blob->length);
 472
 473         /* We hope this value is accruate.  If must be if the GENSEC
 474          * mech does AEAD signing of the packet headers */
 475         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 476
 477         /* sign or seal the packet */
 478         switch (dce_conn->auth_state.auth_info->auth_level) {
 479         case DCERPC_AUTH_LEVEL_PRIVACY:
 480                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 481                                             call,
 482                                             ndr->data + DCERPC_REQUEST_LENGTH,
 483                                             payload_length,
 484                                             blob->data,
 485                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 486                                             &creds2);
 487
 488                 if (NT_STATUS_IS_OK(status)) {
 489                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 490                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
 491                                 status = NT_STATUS_NO_MEMORY;
 492                         else
 493                                 status = NT_STATUS_OK;
 494                 }
 495
 496                 /* If we did AEAD signing of the packet headers, then we hope
 497                  * this value didn't change... */
 498                 dcerpc_set_auth_length(blob, creds2.length);
 499                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 500                 data_blob_free(&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 - dce_conn->auth_state.auth_info->credentials.length,
 510                                             &creds2);
 511                 if (NT_STATUS_IS_OK(status)) {
 512                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 513                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
 514                                 status = NT_STATUS_NO_MEMORY;
 515                         else
 516                                 status = NT_STATUS_OK;
 517                 }
 518
 519                 /* If we did AEAD signing of the packet headers, then we hope
 520                  * this value didn't change... */
 521                 dcerpc_set_auth_length(blob, creds2.length);
 522                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 523                 data_blob_free(&creds2);
 524                 break;
 525
 526         case DCERPC_AUTH_LEVEL_CONNECT:
 527                 break;
 528
 529         default:
 530                 status = NT_STATUS_INVALID_LEVEL;
 531                 break;
 532         }
 533
 534         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 535
 536         if (!NT_STATUS_IS_OK(status)) {
 537                 return false;
 538         }
 539
 540         return true;
 541 }