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