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