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 "librpc/gen_ndr/ndr_dcerpc.h"
  26 #include "auth/credentials/credentials.h"
  27 #include "auth/gensec/gensec.h"
  28 #include "param/param.h"
  29
  30 /*
  31   parse any auth information from a dcerpc bind request
  32   return false if we can't handle the auth request for some
  33   reason (in which case we send a bind_nak)
  34 */
  35 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
  36 {
  37         struct cli_credentials *server_credentials;
  38         struct ncacn_packet *pkt = &call->pkt;
  39         struct dcesrv_connection *dce_conn = call->conn;
  40         struct dcesrv_auth *auth = &dce_conn->auth_state;
  41         NTSTATUS status;
  42         enum ndr_err_code ndr_err;
  43
  44         if (pkt->u.bind.auth_info.length == 0) {
  45                 dce_conn->auth_state.auth_info = NULL;
  46                 return true;
  47         }
  48
  49         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  50         if (!dce_conn->auth_state.auth_info) {
  51                 return false;
  52         }
  53
  54         ndr_err = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
  55                                        call,
  56                                        dce_conn->auth_state.auth_info,
  57                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
  58         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  59                 return false;
  60         }
  61
  62         status = gensec_server_start(dce_conn, call->event_ctx, call->conn->dce_ctx->lp_ctx, call->msg_ctx, &auth->gensec_security);
  63         if (!NT_STATUS_IS_OK(status)) {
  64                 DEBUG(1, ("Failed to start GENSEC for DCERPC server: %s\n", nt_errstr(status)));
  65                 return false;
  66         }
  67
  68         server_credentials
  69                 = cli_credentials_init(call);
  70         if (!server_credentials) {
  71                 DEBUG(1, ("Failed to init server credentials\n"));
  72                 return false;
  73         }
  74
  75         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  76         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  77         if (!NT_STATUS_IS_OK(status)) {
  78                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  79                 talloc_free(server_credentials);
  80                 server_credentials = NULL;
  81         }
  82
  83         gensec_set_credentials(auth->gensec_security, server_credentials);
  84
  85         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  86                                                auth->auth_info->auth_level);
  87
  88         if (!NT_STATUS_IS_OK(status)) {
  89                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
  90                           (int)auth->auth_info->auth_type,
  91                           (int)auth->auth_info->auth_level,
  92                           nt_errstr(status)));
  93                 return false;
  94         }
  95
  96         return true;
  97 }
  98
  99 /*
 100   add any auth information needed in a bind ack, and process the authentication
 101   information found in the bind.
 102 */
 103 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 104 {
 105         struct dcesrv_connection *dce_conn = call->conn;
 106         NTSTATUS status;
 107
 108         if (!call->conn->auth_state.gensec_security) {
 109                 return NT_STATUS_OK;
 110         }
 111
 112         status = gensec_update(dce_conn->auth_state.gensec_security,
 113                                call,
 114                                dce_conn->auth_state.auth_info->credentials,
 115                                &dce_conn->auth_state.auth_info->credentials);
 116
 117         if (NT_STATUS_IS_OK(status)) {
 118                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 119                                              &dce_conn->auth_state.session_info);
 120                 if (!NT_STATUS_IS_OK(status)) {
 121                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 122                         return status;
 123                 }
 124
 125                 /* Now that we are authenticated, go back to the generic session key... */
 126                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 127                 return NT_STATUS_OK;
 128         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 129                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 130                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 131                 return NT_STATUS_OK;
 132         } else {
 133                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 134                 return status;
 135         }
 136 }
 137
 138
 139 /*
 140   process the final stage of a auth request
 141 */
 142 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 143 {
 144         struct ncacn_packet *pkt = &call->pkt;
 145         struct dcesrv_connection *dce_conn = call->conn;
 146         NTSTATUS status;
 147         enum ndr_err_code ndr_err;
 148
 149         /* We can't work without an existing gensec state, and an new blob to feed it */
 150         if (!dce_conn->auth_state.auth_info ||
 151             !dce_conn->auth_state.gensec_security ||
 152             pkt->u.auth3.auth_info.length == 0) {
 153                 return false;
 154         }
 155
 156         ndr_err = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 157                                        call,
 158                                        dce_conn->auth_state.auth_info,
 159                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 160         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 161                 return false;
 162         }
 163
 164         /* Pass the extra data we got from the client down to gensec for processing */
 165         status = gensec_update(dce_conn->auth_state.gensec_security,
 166                                call,
 167                                dce_conn->auth_state.auth_info->credentials,
 168                                &dce_conn->auth_state.auth_info->credentials);
 169         if (NT_STATUS_IS_OK(status)) {
 170                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 171                                              &dce_conn->auth_state.session_info);
 172                 if (!NT_STATUS_IS_OK(status)) {
 173                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 174                         return false;
 175                 }
 176                 /* Now that we are authenticated, go back to the generic session key... */
 177                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 178                 return true;
 179         } else {
 180                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 181                           nt_errstr(status)));
 182                 return false;
 183         }
 184
 185         return true;
 186 }
 187
 188 /*
 189   parse any auth information from a dcerpc alter request
 190   return false if we can't handle the auth request for some
 191   reason (in which case we send a bind_nak (is this true for here?))
 192 */
 193 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 194 {
 195         struct ncacn_packet *pkt = &call->pkt;
 196         struct dcesrv_connection *dce_conn = call->conn;
 197         enum ndr_err_code ndr_err;
 198
 199         /* on a pure interface change there is no auth blob */
 200         if (pkt->u.alter.auth_info.length == 0) {
 201                 return true;
 202         }
 203
 204         /* We can't work without an existing gensec state */
 205         if (!dce_conn->auth_state.gensec_security) {
 206                 return false;
 207         }
 208
 209         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 210         if (!dce_conn->auth_state.auth_info) {
 211                 return false;
 212         }
 213
 214         ndr_err = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 215                                        call,
 216                                        dce_conn->auth_state.auth_info,
 217                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 218         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 219                 return false;
 220         }
 221
 222         return true;
 223 }
 224
 225 /*
 226   add any auth information needed in a alter ack, and process the authentication
 227   information found in the alter.
 228 */
 229 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 230 {
 231         struct dcesrv_connection *dce_conn = call->conn;
 232         NTSTATUS status;
 233
 234         /* on a pure interface change there is no auth_info structure
 235            setup */
 236         if (!call->conn->auth_state.auth_info ||
 237             dce_conn->auth_state.auth_info->credentials.length == 0) {
 238                 return NT_STATUS_OK;
 239         }
 240
 241         if (!call->conn->auth_state.gensec_security) {
 242                 return NT_STATUS_INVALID_PARAMETER;
 243         }
 244
 245         status = gensec_update(dce_conn->auth_state.gensec_security,
 246                                call,
 247                                dce_conn->auth_state.auth_info->credentials,
 248                                &dce_conn->auth_state.auth_info->credentials);
 249
 250         if (NT_STATUS_IS_OK(status)) {
 251                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 252                                              &dce_conn->auth_state.session_info);
 253                 if (!NT_STATUS_IS_OK(status)) {
 254                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 255                         return status;
 256                 }
 257
 258                 /* Now that we are authenticated, got back to the generic session key... */
 259                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 260                 return NT_STATUS_OK;
 261         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 262                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 263                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 264                 return NT_STATUS_OK;
 265         }
 266
 267         DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 268         return status;
 269 }
 270
 271 /*
 272   generate a CONNECT level verifier
 273 */
 274 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 275 {
 276         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 277         if (blob->data == NULL) {
 278                 return NT_STATUS_NO_MEMORY;
 279         }
 280         SIVAL(blob->data, 0, 1);
 281         memset(blob->data+4, 0, 12);
 282         return NT_STATUS_OK;
 283 }
 284
 285 /*
 286   generate a CONNECT level verifier
 287 */
 288 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 289 {
 290         if (blob->length != 16 ||
 291             IVAL(blob->data, 0) != 1) {
 292                 return NT_STATUS_ACCESS_DENIED;
 293         }
 294         return NT_STATUS_OK;
 295 }
 296
 297
 298 /*
 299   check credentials on a request
 300 */
 301 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 302 {
 303         struct ncacn_packet *pkt = &call->pkt;
 304         struct dcesrv_connection *dce_conn = call->conn;
 305         DATA_BLOB auth_blob;
 306         struct dcerpc_auth auth;
 307         struct ndr_pull *ndr;
 308         NTSTATUS status;
 309         enum ndr_err_code ndr_err;
 310
 311         if (!dce_conn->auth_state.auth_info ||
 312             !dce_conn->auth_state.gensec_security) {
 313                 return true;
 314         }
 315
 316         auth_blob.length = 8 + pkt->auth_length;
 317
 318         /* check for a valid length */
 319         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 320                 return false;
 321         }
 322
 323         auth_blob.data =
 324                 pkt->u.request.stub_and_verifier.data +
 325                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 326         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 327
 328         /* pull the auth structure */
 329         ndr = ndr_pull_init_blob(&auth_blob, call, lp_iconv_convenience(call->conn->dce_ctx->lp_ctx));
 330         if (!ndr) {
 331                 return false;
 332         }
 333
 334         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 335                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 336         }
 337
 338         ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 339         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 340                 talloc_free(ndr);
 341                 return false;
 342         }
 343
 344         /* check signature or unseal the packet */
 345         switch (dce_conn->auth_state.auth_info->auth_level) {
 346         case DCERPC_AUTH_LEVEL_PRIVACY:
 347                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 348                                               call,
 349                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 350                                               pkt->u.request.stub_and_verifier.length,
 351                                               full_packet->data,
 352                                               full_packet->length-auth.credentials.length,
 353                                               &auth.credentials);
 354                 memcpy(pkt->u.request.stub_and_verifier.data,
 355                        full_packet->data + DCERPC_REQUEST_LENGTH,
 356                        pkt->u.request.stub_and_verifier.length);
 357                 break;
 358
 359         case DCERPC_AUTH_LEVEL_INTEGRITY:
 360                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 361                                              call,
 362                                              pkt->u.request.stub_and_verifier.data,
 363                                              pkt->u.request.stub_and_verifier.length,
 364                                              full_packet->data,
 365                                              full_packet->length-auth.credentials.length,
 366                                              &auth.credentials);
 367                 break;
 368
 369         case DCERPC_AUTH_LEVEL_CONNECT:
 370                 status = dcesrv_check_connect_verifier(&auth.credentials);
 371                 break;
 372
 373         default:
 374                 status = NT_STATUS_INVALID_LEVEL;
 375                 break;
 376         }
 377
 378         /* remove the indicated amount of padding */
 379         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 380                 talloc_free(ndr);
 381                 return false;
 382         }
 383         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 384         talloc_free(ndr);
 385
 386         return NT_STATUS_IS_OK(status);
 387 }
 388
 389
 390 /*
 391    push a signed or sealed dcerpc request packet into a blob
 392 */
 393 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 394                           DATA_BLOB *blob, struct ncacn_packet *pkt)
 395 {
 396         struct dcesrv_connection *dce_conn = call->conn;
 397         NTSTATUS status;
 398         enum ndr_err_code ndr_err;
 399         struct ndr_push *ndr;
 400         uint32_t payload_length;
 401         DATA_BLOB creds2;
 402
 403         /* non-signed packets are simple */
 404         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 405                 status = ncacn_push_auth(blob, call, pkt, NULL);
 406                 return NT_STATUS_IS_OK(status);
 407         }
 408
 409         ndr = ndr_push_init_ctx(call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx));
 410         if (!ndr) {
 411                 return false;
 412         }
 413
 414         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 415                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 416         }
 417
 418         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 419         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 420                 return false;
 421         }
 422
 423         /* pad to 16 byte multiple, match win2k3 */
 424         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 16);
 425         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 426
 427         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 428
 429         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 430                 status = dcesrv_connect_verifier(call,
 431                                                  &dce_conn->auth_state.auth_info->credentials);
 432                 if (!NT_STATUS_IS_OK(status)) {
 433                         return false;
 434                 }
 435         } else {
 436
 437                 /* We hope this length is accruate.  If must be if the
 438                  * GENSEC mech does AEAD signing of the packet
 439                  * headers */
 440                 dce_conn->auth_state.auth_info->credentials
 441                         = data_blob_talloc(call, NULL,
 442                                            gensec_sig_size(dce_conn->auth_state.gensec_security,
 443                                                            payload_length));
 444                 data_blob_clear(&dce_conn->auth_state.auth_info->credentials);
 445         }
 446
 447         /* add the auth verifier */
 448         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 449                                       dce_conn->auth_state.auth_info);
 450         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 451                 return false;
 452         }
 453
 454         /* extract the whole packet as a blob */
 455         *blob = ndr_push_blob(ndr);
 456
 457         /* fill in the fragment length and auth_length, we can't fill
 458            in these earlier as we don't know the signature length (it
 459            could be variable length) */
 460         dcerpc_set_frag_length(blob, blob->length);
 461
 462         /* We hope this value is accruate.  If must be if the GENSEC
 463          * mech does AEAD signing of the packet headers */
 464         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 465
 466         /* sign or seal the packet */
 467         switch (dce_conn->auth_state.auth_info->auth_level) {
 468         case DCERPC_AUTH_LEVEL_PRIVACY:
 469                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 470                                             call,
 471                                             ndr->data + DCERPC_REQUEST_LENGTH,
 472                                             payload_length,
 473                                             blob->data,
 474                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 475                                             &creds2);
 476
 477                 if (NT_STATUS_IS_OK(status)) {
 478                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 479                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
 480                                 status = NT_STATUS_NO_MEMORY;
 481                         else
 482                                 status = NT_STATUS_OK;
 483                 }
 484
 485                 /* If we did AEAD signing of the packet headers, then we hope
 486                  * this value didn't change... */
 487                 dcerpc_set_auth_length(blob, creds2.length);
 488                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 489                 data_blob_free(&creds2);
 490                 break;
 491
 492         case DCERPC_AUTH_LEVEL_INTEGRITY:
 493                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 494                                             call,
 495                                             ndr->data + DCERPC_REQUEST_LENGTH,
 496                                             payload_length,
 497                                             blob->data,
 498                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 499                                             &creds2);
 500                 if (NT_STATUS_IS_OK(status)) {
 501                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 502                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
 503                                 status = NT_STATUS_NO_MEMORY;
 504                         else
 505                                 status = NT_STATUS_OK;
 506                 }
 507
 508                 /* If we did AEAD signing of the packet headers, then we hope
 509                  * this value didn't change... */
 510                 dcerpc_set_auth_length(blob, creds2.length);
 511                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 512                 data_blob_free(&creds2);
 513                 break;
 514
 515         case DCERPC_AUTH_LEVEL_CONNECT:
 516                 break;
 517
 518         default:
 519                 status = NT_STATUS_INVALID_LEVEL;
 520                 break;
 521         }
 522
 523         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 524
 525         if (!NT_STATUS_IS_OK(status)) {
 526                 return false;
 527         }
 528
 529         return true;
 530 }