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                 /* Now that we are authenticated, go back to the generic session key... */
 128                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 129                 return NT_STATUS_OK;
 130         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 131                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 132                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 133                 return NT_STATUS_OK;
 134         } else {
 135                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 136                 return status;
 137         }
 138 }
 139
 140
 141 /*
 142   process the final stage of a auth request
 143 */
 144 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 145 {
 146         struct ncacn_packet *pkt = &call->pkt;
 147         struct dcesrv_connection *dce_conn = call->conn;
 148         NTSTATUS status;
 149         enum ndr_err_code ndr_err;
 150
 151         /* We can't work without an existing gensec state, and an new blob to feed it */
 152         if (!dce_conn->auth_state.auth_info ||
 153             !dce_conn->auth_state.gensec_security ||
 154             pkt->u.auth3.auth_info.length == 0) {
 155                 return false;
 156         }
 157
 158         ndr_err = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 159                                        call, NULL,
 160                                        dce_conn->auth_state.auth_info,
 161                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 162         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 163                 return false;
 164         }
 165
 166         /* Pass the extra data we got from the client down to gensec for processing */
 167         status = gensec_update(dce_conn->auth_state.gensec_security,
 168                                call,
 169                                dce_conn->auth_state.auth_info->credentials,
 170                                &dce_conn->auth_state.auth_info->credentials);
 171         if (NT_STATUS_IS_OK(status)) {
 172                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 173                                              &dce_conn->auth_state.session_info);
 174                 if (!NT_STATUS_IS_OK(status)) {
 175                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 176                         return false;
 177                 }
 178                 /* Now that we are authenticated, go back to the generic session key... */
 179                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 180                 return true;
 181         } else {
 182                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 183                           nt_errstr(status)));
 184                 return false;
 185         }
 186
 187         return true;
 188 }
 189
 190 /*
 191   parse any auth information from a dcerpc alter request
 192   return false if we can't handle the auth request for some
 193   reason (in which case we send a bind_nak (is this true for here?))
 194 */
 195 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 196 {
 197         struct ncacn_packet *pkt = &call->pkt;
 198         struct dcesrv_connection *dce_conn = call->conn;
 199         enum ndr_err_code ndr_err;
 200
 201         /* on a pure interface change there is no auth blob */
 202         if (pkt->u.alter.auth_info.length == 0) {
 203                 return true;
 204         }
 205
 206         /* We can't work without an existing gensec state */
 207         if (!dce_conn->auth_state.gensec_security) {
 208                 return false;
 209         }
 210
 211         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 212         if (!dce_conn->auth_state.auth_info) {
 213                 return false;
 214         }
 215
 216         ndr_err = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 217                                        call, NULL,
 218                                        dce_conn->auth_state.auth_info,
 219                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 220         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 221                 return false;
 222         }
 223
 224         return true;
 225 }
 226
 227 /*
 228   add any auth information needed in a alter ack, and process the authentication
 229   information found in the alter.
 230 */
 231 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 232 {
 233         struct dcesrv_connection *dce_conn = call->conn;
 234         NTSTATUS status;
 235
 236         /* on a pure interface change there is no auth_info structure
 237            setup */
 238         if (!call->conn->auth_state.auth_info ||
 239             dce_conn->auth_state.auth_info->credentials.length == 0) {
 240                 return NT_STATUS_OK;
 241         }
 242
 243         if (!call->conn->auth_state.gensec_security) {
 244                 return NT_STATUS_INVALID_PARAMETER;
 245         }
 246
 247         status = gensec_update(dce_conn->auth_state.gensec_security,
 248                                call,
 249                                dce_conn->auth_state.auth_info->credentials,
 250                                &dce_conn->auth_state.auth_info->credentials);
 251
 252         if (NT_STATUS_IS_OK(status)) {
 253                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 254                                              &dce_conn->auth_state.session_info);
 255                 if (!NT_STATUS_IS_OK(status)) {
 256                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 257                         return status;
 258                 }
 259
 260                 /* Now that we are authenticated, got back to the generic session key... */
 261                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 262                 return NT_STATUS_OK;
 263         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 264                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 265                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 266                 return NT_STATUS_OK;
 267         }
 268
 269         DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 270         return status;
 271 }
 272
 273 /*
 274   generate a CONNECT level verifier
 275 */
 276 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 277 {
 278         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 279         if (blob->data == NULL) {
 280                 return NT_STATUS_NO_MEMORY;
 281         }
 282         SIVAL(blob->data, 0, 1);
 283         memset(blob->data+4, 0, 12);
 284         return NT_STATUS_OK;
 285 }
 286
 287 /*
 288   generate a CONNECT level verifier
 289 */
 290 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 291 {
 292         if (blob->length != 16 ||
 293             IVAL(blob->data, 0) != 1) {
 294                 return NT_STATUS_ACCESS_DENIED;
 295         }
 296         return NT_STATUS_OK;
 297 }
 298
 299
 300 /*
 301   check credentials on a request
 302 */
 303 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 304 {
 305         struct ncacn_packet *pkt = &call->pkt;
 306         struct dcesrv_connection *dce_conn = call->conn;
 307         DATA_BLOB auth_blob;
 308         struct dcerpc_auth auth;
 309         struct ndr_pull *ndr;
 310         NTSTATUS status;
 311         enum ndr_err_code ndr_err;
 312
 313         if (!dce_conn->auth_state.auth_info ||
 314             !dce_conn->auth_state.gensec_security) {
 315                 return true;
 316         }
 317
 318         auth_blob.length = 8 + pkt->auth_length;
 319
 320         /* check for a valid length */
 321         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 322                 return false;
 323         }
 324
 325         auth_blob.data =
 326                 pkt->u.request.stub_and_verifier.data +
 327                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 328         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 329
 330         /* pull the auth structure */
 331         ndr = ndr_pull_init_blob(&auth_blob, call, lp_iconv_convenience(call->conn->dce_ctx->lp_ctx));
 332         if (!ndr) {
 333                 return false;
 334         }
 335
 336         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 337                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 338         }
 339
 340         ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 341         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 342                 talloc_free(ndr);
 343                 return false;
 344         }
 345
 346         /* check signature or unseal the packet */
 347         switch (dce_conn->auth_state.auth_info->auth_level) {
 348         case DCERPC_AUTH_LEVEL_PRIVACY:
 349                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 350                                               call,
 351                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 352                                               pkt->u.request.stub_and_verifier.length,
 353                                               full_packet->data,
 354                                               full_packet->length-auth.credentials.length,
 355                                               &auth.credentials);
 356                 memcpy(pkt->u.request.stub_and_verifier.data,
 357                        full_packet->data + DCERPC_REQUEST_LENGTH,
 358                        pkt->u.request.stub_and_verifier.length);
 359                 break;
 360
 361         case DCERPC_AUTH_LEVEL_INTEGRITY:
 362                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 363                                              call,
 364                                              pkt->u.request.stub_and_verifier.data,
 365                                              pkt->u.request.stub_and_verifier.length,
 366                                              full_packet->data,
 367                                              full_packet->length-auth.credentials.length,
 368                                              &auth.credentials);
 369                 break;
 370
 371         case DCERPC_AUTH_LEVEL_CONNECT:
 372                 status = dcesrv_check_connect_verifier(&auth.credentials);
 373                 break;
 374
 375         default:
 376                 status = NT_STATUS_INVALID_LEVEL;
 377                 break;
 378         }
 379
 380         /* remove the indicated amount of padding */
 381         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 382                 talloc_free(ndr);
 383                 return false;
 384         }
 385         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 386         talloc_free(ndr);
 387
 388         return NT_STATUS_IS_OK(status);
 389 }
 390
 391
 392 /*
 393    push a signed or sealed dcerpc request packet into a blob
 394 */
 395 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 396                           DATA_BLOB *blob, struct ncacn_packet *pkt)
 397 {
 398         struct dcesrv_connection *dce_conn = call->conn;
 399         NTSTATUS status;
 400         enum ndr_err_code ndr_err;
 401         struct ndr_push *ndr;
 402         uint32_t payload_length;
 403         DATA_BLOB creds2;
 404
 405         /* non-signed packets are simple */
 406         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 407                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 408                 return NT_STATUS_IS_OK(status);
 409         }
 410
 411         ndr = ndr_push_init_ctx(call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx));
 412         if (!ndr) {
 413                 return false;
 414         }
 415
 416         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 417                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 418         }
 419
 420         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 421         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 422                 return false;
 423         }
 424
 425         /* pad to 16 byte multiple, match win2k3 */
 426         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 16);
 427         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 428
 429         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 430
 431         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 432                 status = dcesrv_connect_verifier(call,
 433                                                  &dce_conn->auth_state.auth_info->credentials);
 434                 if (!NT_STATUS_IS_OK(status)) {
 435                         return false;
 436                 }
 437         } else {
 438
 439                 /* We hope this length is accruate.  If must be if the
 440                  * GENSEC mech does AEAD signing of the packet
 441                  * headers */
 442                 dce_conn->auth_state.auth_info->credentials
 443                         = data_blob_talloc(call, NULL,
 444                                            gensec_sig_size(dce_conn->auth_state.gensec_security,
 445                                                            payload_length));
 446                 data_blob_clear(&dce_conn->auth_state.auth_info->credentials);
 447         }
 448
 449         /* add the auth verifier */
 450         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 451                                       dce_conn->auth_state.auth_info);
 452         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 453                 return false;
 454         }
 455
 456         /* extract the whole packet as a blob */
 457         *blob = ndr_push_blob(ndr);
 458
 459         /* fill in the fragment length and auth_length, we can't fill
 460            in these earlier as we don't know the signature length (it
 461            could be variable length) */
 462         dcerpc_set_frag_length(blob, blob->length);
 463
 464         /* We hope this value is accruate.  If must be if the GENSEC
 465          * mech does AEAD signing of the packet headers */
 466         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 467
 468         /* sign or seal the packet */
 469         switch (dce_conn->auth_state.auth_info->auth_level) {
 470         case DCERPC_AUTH_LEVEL_PRIVACY:
 471                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 472                                             call,
 473                                             ndr->data + DCERPC_REQUEST_LENGTH,
 474                                             payload_length,
 475                                             blob->data,
 476                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 477                                             &creds2);
 478
 479                 if (NT_STATUS_IS_OK(status)) {
 480                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 481                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
 482                                 status = NT_STATUS_NO_MEMORY;
 483                         else
 484                                 status = NT_STATUS_OK;
 485                 }
 486
 487                 /* If we did AEAD signing of the packet headers, then we hope
 488                  * this value didn't change... */
 489                 dcerpc_set_auth_length(blob, creds2.length);
 490                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 491                 data_blob_free(&creds2);
 492                 break;
 493
 494         case DCERPC_AUTH_LEVEL_INTEGRITY:
 495                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 496                                             call,
 497                                             ndr->data + DCERPC_REQUEST_LENGTH,
 498                                             payload_length,
 499                                             blob->data,
 500                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 501                                             &creds2);
 502                 if (NT_STATUS_IS_OK(status)) {
 503                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 504                         if (!data_blob_append(call, blob, creds2.data, creds2.length))
 505                                 status = NT_STATUS_NO_MEMORY;
 506                         else
 507                                 status = NT_STATUS_OK;
 508                 }
 509
 510                 /* If we did AEAD signing of the packet headers, then we hope
 511                  * this value didn't change... */
 512                 dcerpc_set_auth_length(blob, creds2.length);
 513                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 514                 data_blob_free(&creds2);
 515                 break;
 516
 517         case DCERPC_AUTH_LEVEL_CONNECT:
 518                 break;
 519
 520         default:
 521                 status = NT_STATUS_INVALID_LEVEL;
 522                 break;
 523         }
 524
 525         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 526
 527         if (!NT_STATUS_IS_OK(status)) {
 528                 return false;
 529         }
 530
 531         return true;
 532 }