source/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 2 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, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25 #include "rpc_server/dcerpc_server.h"
  26 #include "librpc/gen_ndr/ndr_dcerpc.h"
  27 #include "auth/credentials/credentials.h"
  28 #include "auth/gensec/gensec.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
  43         if (pkt->u.bind.auth_info.length == 0) {
  44                 dce_conn->auth_state.auth_info = NULL;
  45                 return True;
  46         }
  47
  48         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  49         if (!dce_conn->auth_state.auth_info) {
  50                 return False;
  51         }
  52
  53         status = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
  54                                       call,
  55                                       dce_conn->auth_state.auth_info,
  56                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
  57         if (!NT_STATUS_IS_OK(status)) {
  58                 return False;
  59         }
  60
  61         status = gensec_server_start(dce_conn, call->event_ctx, call->msg_ctx, &auth->gensec_security);
  62         if (!NT_STATUS_IS_OK(status)) {
  63                 DEBUG(1, ("Failed to start GENSEC for DCERPC server: %s\n", nt_errstr(status)));
  64                 return False;
  65         }
  66
  67         server_credentials
  68                 = cli_credentials_init(call);
  69         if (!server_credentials) {
  70                 DEBUG(1, ("Failed to init server credentials\n"));
  71                 return False;
  72         }
  73
  74         cli_credentials_set_conf(server_credentials);
  75         status = cli_credentials_set_machine_account(server_credentials);
  76         if (!NT_STATUS_IS_OK(status)) {
  77                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  78                 talloc_free(server_credentials);
  79                 server_credentials = NULL;
  80         }
  81
  82         gensec_set_credentials(auth->gensec_security, server_credentials);
  83
  84         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  85                                                auth->auth_info->auth_level);
  86
  87         if (!NT_STATUS_IS_OK(status)) {
  88                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
  89                           (int)auth->auth_info->auth_type,
  90                           (int)auth->auth_info->auth_level,
  91                           nt_errstr(status)));
  92                 return False;
  93         }
  94
  95         return True;
  96 }
  97
  98 /*
  99   add any auth information needed in a bind ack, and process the authentication
 100   information found in the bind.
 101 */
 102 BOOL dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 103 {
 104         struct dcesrv_connection *dce_conn = call->conn;
 105         NTSTATUS status;
 106
 107         if (!call->conn->auth_state.gensec_security) {
 108                 return True;
 109         }
 110
 111         status = gensec_update(dce_conn->auth_state.gensec_security,
 112                                call,
 113                                dce_conn->auth_state.auth_info->credentials,
 114                                &dce_conn->auth_state.auth_info->credentials);
 115
 116         if (NT_STATUS_IS_OK(status)) {
 117                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 118                                              &dce_conn->auth_state.session_info);
 119                 if (!NT_STATUS_IS_OK(status)) {
 120                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 121                         return False;
 122                 }
 123
 124                 /* Now that we are authenticated, go back to the generic session key... */
 125                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 126                 return True;
 127         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 128                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 129                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 130                 return True;
 131         } else {
 132                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 133                 return False;
 134         }
 135 }
 136
 137
 138 /*
 139   process the final stage of a auth request
 140 */
 141 BOOL dcesrv_auth_auth3(struct dcesrv_call_state *call)
 142 {
 143         struct ncacn_packet *pkt = &call->pkt;
 144         struct dcesrv_connection *dce_conn = call->conn;
 145         NTSTATUS status;
 146
 147         /* We can't work without an existing gensec state, and an new blob to feed it */
 148         if (!dce_conn->auth_state.auth_info ||
 149             !dce_conn->auth_state.gensec_security ||
 150             pkt->u.auth3.auth_info.length == 0) {
 151                 return False;
 152         }
 153
 154         status = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 155                                       call,
 156                                       dce_conn->auth_state.auth_info,
 157                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 158         if (!NT_STATUS_IS_OK(status)) {
 159                 return False;
 160         }
 161
 162         /* Pass the extra data we got from the client down to gensec for processing */
 163         status = gensec_update(dce_conn->auth_state.gensec_security,
 164                                call,
 165                                dce_conn->auth_state.auth_info->credentials,
 166                                &dce_conn->auth_state.auth_info->credentials);
 167         if (NT_STATUS_IS_OK(status)) {
 168                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 169                                              &dce_conn->auth_state.session_info);
 170                 if (!NT_STATUS_IS_OK(status)) {
 171                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 172                         return False;
 173                 }
 174                 /* Now that we are authenticated, go back to the generic session key... */
 175                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 176                 return True;
 177         } else {
 178                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 179                           nt_errstr(status)));
 180                 return False;
 181         }
 182
 183         return True;
 184 }
 185
 186 /*
 187   parse any auth information from a dcerpc alter request
 188   return False if we can't handle the auth request for some
 189   reason (in which case we send a bind_nak (is this true for here?))
 190 */
 191 BOOL dcesrv_auth_alter(struct dcesrv_call_state *call)
 192 {
 193         struct ncacn_packet *pkt = &call->pkt;
 194         struct dcesrv_connection *dce_conn = call->conn;
 195         NTSTATUS status;
 196
 197         /* on a pure interface change there is no auth blob */
 198         if (pkt->u.alter.auth_info.length == 0) {
 199                 return True;
 200         }
 201
 202         /* We can't work without an existing gensec state */
 203         if (!dce_conn->auth_state.gensec_security) {
 204                 return False;
 205         }
 206
 207         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 208         if (!dce_conn->auth_state.auth_info) {
 209                 return False;
 210         }
 211
 212         status = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 213                                       call,
 214                                       dce_conn->auth_state.auth_info,
 215                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 216         if (!NT_STATUS_IS_OK(status)) {
 217                 return False;
 218         }
 219
 220         return True;
 221 }
 222
 223 /*
 224   add any auth information needed in a alter ack, and process the authentication
 225   information found in the alter.
 226 */
 227 BOOL dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 228 {
 229         struct dcesrv_connection *dce_conn = call->conn;
 230         NTSTATUS status;
 231
 232         /* on a pure interface change there is no auth_info structure
 233            setup */
 234         if (!call->conn->auth_state.auth_info ||
 235             dce_conn->auth_state.auth_info->credentials.length == 0) {
 236                 return True;
 237         }
 238
 239         if (!call->conn->auth_state.gensec_security) {
 240                 return False;
 241         }
 242
 243         status = gensec_update(dce_conn->auth_state.gensec_security,
 244                                call,
 245                                dce_conn->auth_state.auth_info->credentials,
 246                                &dce_conn->auth_state.auth_info->credentials);
 247
 248         if (NT_STATUS_IS_OK(status)) {
 249                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 250                                              &dce_conn->auth_state.session_info);
 251                 if (!NT_STATUS_IS_OK(status)) {
 252                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 253                         return False;
 254                 }
 255
 256                 /* Now that we are authenticated, got back to the generic session key... */
 257                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 258                 return True;
 259         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 260                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 261                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 262                 return True;
 263         }
 264
 265         DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 266         return False;
 267 }
 268
 269 /*
 270   generate a CONNECT level verifier
 271 */
 272 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 273 {
 274         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 275         if (blob->data == NULL) {
 276                 return NT_STATUS_NO_MEMORY;
 277         }
 278         SIVAL(blob->data, 0, 1);
 279         memset(blob->data+4, 0, 12);
 280         return NT_STATUS_OK;
 281 }
 282
 283 /*
 284   generate a CONNECT level verifier
 285 */
 286 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 287 {
 288         if (blob->length != 16 ||
 289             IVAL(blob->data, 0) != 1) {
 290                 return NT_STATUS_ACCESS_DENIED;
 291         }
 292         return NT_STATUS_OK;
 293 }
 294
 295
 296 /*
 297   check credentials on a request
 298 */
 299 BOOL dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 300 {
 301         struct ncacn_packet *pkt = &call->pkt;
 302         struct dcesrv_connection *dce_conn = call->conn;
 303         DATA_BLOB auth_blob;
 304         struct dcerpc_auth auth;
 305         struct ndr_pull *ndr;
 306         NTSTATUS status;
 307
 308         if (!dce_conn->auth_state.auth_info ||
 309             !dce_conn->auth_state.gensec_security) {
 310                 return True;
 311         }
 312
 313         auth_blob.length = 8 + pkt->auth_length;
 314
 315         /* check for a valid length */
 316         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 317                 return False;
 318         }
 319
 320         auth_blob.data =
 321                 pkt->u.request.stub_and_verifier.data +
 322                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 323         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 324
 325         /* pull the auth structure */
 326         ndr = ndr_pull_init_blob(&auth_blob, call);
 327         if (!ndr) {
 328                 return False;
 329         }
 330
 331         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 332                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 333         }
 334
 335         status = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 336         if (!NT_STATUS_IS_OK(status)) {
 337                 talloc_free(ndr);
 338                 return False;
 339         }
 340
 341         /* check signature or unseal the packet */
 342         switch (dce_conn->auth_state.auth_info->auth_level) {
 343         case DCERPC_AUTH_LEVEL_PRIVACY:
 344                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 345                                               call,
 346                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 347                                               pkt->u.request.stub_and_verifier.length,
 348                                               full_packet->data,
 349                                               full_packet->length-auth.credentials.length,
 350                                               &auth.credentials);
 351                 memcpy(pkt->u.request.stub_and_verifier.data,
 352                        full_packet->data + DCERPC_REQUEST_LENGTH,
 353                        pkt->u.request.stub_and_verifier.length);
 354                 break;
 355
 356         case DCERPC_AUTH_LEVEL_INTEGRITY:
 357                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 358                                              call,
 359                                              pkt->u.request.stub_and_verifier.data,
 360                                              pkt->u.request.stub_and_verifier.length,
 361                                              full_packet->data,
 362                                              full_packet->length-auth.credentials.length,
 363                                              &auth.credentials);
 364                 break;
 365
 366         case DCERPC_AUTH_LEVEL_CONNECT:
 367                 status = dcesrv_check_connect_verifier(&auth.credentials);
 368                 break;
 369
 370         default:
 371                 status = NT_STATUS_INVALID_LEVEL;
 372                 break;
 373         }
 374
 375         /* remove the indicated amount of padding */
 376         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 377                 talloc_free(ndr);
 378                 return False;
 379         }
 380         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 381         talloc_free(ndr);
 382
 383         return NT_STATUS_IS_OK(status);
 384 }
 385
 386
 387 /*
 388    push a signed or sealed dcerpc request packet into a blob
 389 */
 390 BOOL dcesrv_auth_response(struct dcesrv_call_state *call,
 391                           DATA_BLOB *blob, struct ncacn_packet *pkt)
 392 {
 393         struct dcesrv_connection *dce_conn = call->conn;
 394         NTSTATUS status;
 395         struct ndr_push *ndr;
 396         uint32_t payload_length;
 397         DATA_BLOB creds2;
 398
 399         /* non-signed packets are simple */
 400         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 401                 status = ncacn_push_auth(blob, call, pkt, NULL);
 402                 return NT_STATUS_IS_OK(status);
 403         }
 404
 405         ndr = ndr_push_init_ctx(call);
 406         if (!ndr) {
 407                 return False;
 408         }
 409
 410         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 411                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 412         }
 413
 414         status = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 415         if (!NT_STATUS_IS_OK(status)) {
 416                 return False;
 417         }
 418
 419         /* pad to 16 byte multiple, match win2k3 */
 420         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 16);
 421         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 422
 423         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 424
 425         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 426                 status = dcesrv_connect_verifier(call,
 427                                                  &dce_conn->auth_state.auth_info->credentials);
 428                 if (!NT_STATUS_IS_OK(status)) {
 429                         return False;
 430                 }
 431         } else {
 432
 433                 /* We hope this length is accruate.  If must be if the
 434                  * GENSEC mech does AEAD signing of the packet
 435                  * headers */
 436                 dce_conn->auth_state.auth_info->credentials
 437                         = data_blob_talloc(call, NULL,
 438                                            gensec_sig_size(dce_conn->auth_state.gensec_security,
 439                                                            payload_length));
 440                 data_blob_clear(&dce_conn->auth_state.auth_info->credentials);
 441         }
 442
 443         /* add the auth verifier */
 444         status = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 445                                       dce_conn->auth_state.auth_info);
 446         if (!NT_STATUS_IS_OK(status)) {
 447                 return False;
 448         }
 449
 450         /* extract the whole packet as a blob */
 451         *blob = ndr_push_blob(ndr);
 452
 453         /* fill in the fragment length and auth_length, we can't fill
 454            in these earlier as we don't know the signature length (it
 455            could be variable length) */
 456         dcerpc_set_frag_length(blob, blob->length);
 457
 458         /* We hope this value is accruate.  If must be if the GENSEC
 459          * mech does AEAD signing of the packet headers */
 460         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 461
 462         /* sign or seal the packet */
 463         switch (dce_conn->auth_state.auth_info->auth_level) {
 464         case DCERPC_AUTH_LEVEL_PRIVACY:
 465                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 466                                             call,
 467                                             ndr->data + DCERPC_REQUEST_LENGTH,
 468                                             payload_length,
 469                                             blob->data,
 470                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 471                                             &creds2);
 472
 473                 if (NT_STATUS_IS_OK(status)) {
 474                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 475                         status = data_blob_append(call, blob, creds2.data, creds2.length);
 476                 }
 477
 478                 /* If we did AEAD signing of the packet headers, then we hope
 479                  * this value didn't change... */
 480                 dcerpc_set_auth_length(blob, creds2.length);
 481                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 482                 data_blob_free(&creds2);
 483                 break;
 484
 485         case DCERPC_AUTH_LEVEL_INTEGRITY:
 486                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 487                                             call,
 488                                             ndr->data + DCERPC_REQUEST_LENGTH,
 489                                             payload_length,
 490                                             blob->data,
 491                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 492                                             &creds2);
 493                 if (NT_STATUS_IS_OK(status)) {
 494                         blob->length -= dce_conn->auth_state.auth_info->credentials.length;
 495                         status = data_blob_append(call, blob, creds2.data, creds2.length);
 496                 }
 497
 498                 /* If we did AEAD signing of the packet headers, then we hope
 499                  * this value didn't change... */
 500                 dcerpc_set_auth_length(blob, creds2.length);
 501                 dcerpc_set_frag_length(blob, dcerpc_get_frag_length(blob)+creds2.length);
 502                 data_blob_free(&creds2);
 503                 break;
 504
 505         case DCERPC_AUTH_LEVEL_CONNECT:
 506                 break;
 507
 508         default:
 509                 status = NT_STATUS_INVALID_LEVEL;
 510                 break;
 511         }
 512
 513         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 514
 515         if (!NT_STATUS_IS_OK(status)) {
 516                 return False;
 517         }
 518
 519         return True;
 520 }