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 "rpc_server/common/proto.h"
  27 #include "librpc/rpc/dcerpc_proto.h"
  28 #include "librpc/gen_ndr/ndr_dcerpc.h"
  29 #include "auth/credentials/credentials.h"
  30 #include "auth/gensec/gensec.h"
  31 #include "auth/auth.h"
  32 #include "param/param.h"
  33
  34 /*
  35   parse any auth information from a dcerpc bind request
  36   return false if we can't handle the auth request for some
  37   reason (in which case we send a bind_nak)
  38 */
  39 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
  40 {
  41         struct cli_credentials *server_credentials;
  42         struct ncacn_packet *pkt = &call->pkt;
  43         struct dcesrv_connection *dce_conn = call->conn;
  44         struct dcesrv_auth *auth = &dce_conn->auth_state;
  45         NTSTATUS status;
  46         uint32_t auth_length;
  47
  48         if (pkt->u.bind.auth_info.length == 0) {
  49                 dce_conn->auth_state.auth_info = NULL;
  50                 return true;
  51         }
  52
  53         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  54         if (!dce_conn->auth_state.auth_info) {
  55                 return false;
  56         }
  57
  58         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.bind.auth_info,
  59                                           dce_conn->auth_state.auth_info,
  60                                           &auth_length, false);
  61         server_credentials
  62                 = cli_credentials_init(call);
  63         if (!server_credentials) {
  64                 DEBUG(1, ("Failed to init server credentials\n"));
  65                 return false;
  66         }
  67
  68         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  69         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  70         if (!NT_STATUS_IS_OK(status)) {
  71                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  72                 talloc_free(server_credentials);
  73                 server_credentials = NULL;
  74         }
  75
  76         status = samba_server_gensec_start(dce_conn, call->event_ctx,
  77                                            call->msg_ctx,
  78                                            call->conn->dce_ctx->lp_ctx,
  79                                            server_credentials,
  80                                            NULL,
  81                                            &auth->gensec_security);
  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(3, ("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         if (call->conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
  95                 gensec_want_feature(auth->gensec_security, GENSEC_FEATURE_SIGN_PKT_HEADER);
  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                 if (dce_conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
 128                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 129                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 130                 }
 131
 132                 /* Now that we are authenticated, go back to the generic session key... */
 133                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 134                 return NT_STATUS_OK;
 135         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 136                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 137                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 138                 return NT_STATUS_OK;
 139         } else {
 140                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_ack: %s\n",
 141                           nt_errstr(status)));
 142                 return status;
 143         }
 144 }
 145
 146
 147 /*
 148   process the final stage of a auth request
 149 */
 150 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 151 {
 152         struct ncacn_packet *pkt = &call->pkt;
 153         struct dcesrv_connection *dce_conn = call->conn;
 154         NTSTATUS status;
 155         uint32_t auth_length;
 156
 157         /* We can't work without an existing gensec state, and an new blob to feed it */
 158         if (!dce_conn->auth_state.auth_info ||
 159             !dce_conn->auth_state.gensec_security ||
 160             pkt->u.auth3.auth_info.length == 0) {
 161                 return false;
 162         }
 163
 164         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.auth3.auth_info,
 165                                           dce_conn->auth_state.auth_info, &auth_length, true);
 166         if (!NT_STATUS_IS_OK(status)) {
 167                 return false;
 168         }
 169
 170         /* Pass the extra data we got from the client down to gensec for processing */
 171         status = gensec_update(dce_conn->auth_state.gensec_security,
 172                                call,
 173                                dce_conn->auth_state.auth_info->credentials,
 174                                &dce_conn->auth_state.auth_info->credentials);
 175         if (NT_STATUS_IS_OK(status)) {
 176                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 177                                              &dce_conn->auth_state.session_info);
 178                 if (!NT_STATUS_IS_OK(status)) {
 179                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 180                         return false;
 181                 }
 182                 /* Now that we are authenticated, go back to the generic session key... */
 183                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 184                 return true;
 185         } else {
 186                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_auth3: %s\n",
 187                           nt_errstr(status)));
 188                 return false;
 189         }
 190 }
 191
 192 /*
 193   parse any auth information from a dcerpc alter request
 194   return false if we can't handle the auth request for some
 195   reason (in which case we send a bind_nak (is this true for here?))
 196 */
 197 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 198 {
 199         struct ncacn_packet *pkt = &call->pkt;
 200         struct dcesrv_connection *dce_conn = call->conn;
 201         NTSTATUS status;
 202         uint32_t auth_length;
 203
 204         /* on a pure interface change there is no auth blob */
 205         if (pkt->u.alter.auth_info.length == 0) {
 206                 return true;
 207         }
 208
 209         /* We can't work without an existing gensec state */
 210         if (!dce_conn->auth_state.gensec_security) {
 211                 return false;
 212         }
 213
 214         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 215         if (!dce_conn->auth_state.auth_info) {
 216                 return false;
 217         }
 218
 219         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.alter.auth_info,
 220                                           dce_conn->auth_state.auth_info,
 221                                           &auth_length, true);
 222         if (!NT_STATUS_IS_OK(status)) {
 223                 return false;
 224         }
 225
 226         return true;
 227 }
 228
 229 /*
 230   add any auth information needed in a alter ack, and process the authentication
 231   information found in the alter.
 232 */
 233 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 234 {
 235         struct dcesrv_connection *dce_conn = call->conn;
 236         NTSTATUS status;
 237
 238         /* on a pure interface change there is no auth_info structure
 239            setup */
 240         if (!call->conn->auth_state.auth_info ||
 241             dce_conn->auth_state.auth_info->credentials.length == 0) {
 242                 return NT_STATUS_OK;
 243         }
 244
 245         if (!call->conn->auth_state.gensec_security) {
 246                 return NT_STATUS_INVALID_PARAMETER;
 247         }
 248
 249         status = gensec_update(dce_conn->auth_state.gensec_security,
 250                                call,
 251                                dce_conn->auth_state.auth_info->credentials,
 252                                &dce_conn->auth_state.auth_info->credentials);
 253
 254         if (NT_STATUS_IS_OK(status)) {
 255                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 256                                              &dce_conn->auth_state.session_info);
 257                 if (!NT_STATUS_IS_OK(status)) {
 258                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 259                         return status;
 260                 }
 261
 262                 /* Now that we are authenticated, got back to the generic session key... */
 263                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 264                 return NT_STATUS_OK;
 265         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 266                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 267                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 268                 return NT_STATUS_OK;
 269         }
 270
 271         DEBUG(4, ("GENSEC mech rejected the incoming authentication at auth alter_ack: %s\n",
 272                   nt_errstr(status)));
 273         return status;
 274 }
 275
 276 /*
 277   check credentials on a request
 278 */
 279 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 280 {
 281         struct ncacn_packet *pkt = &call->pkt;
 282         struct dcesrv_connection *dce_conn = call->conn;
 283         struct dcerpc_auth auth;
 284         NTSTATUS status;
 285         uint32_t auth_length;
 286         size_t hdr_size = DCERPC_REQUEST_LENGTH;
 287
 288         if (!dce_conn->auth_state.auth_info ||
 289             !dce_conn->auth_state.gensec_security) {
 290                 return true;
 291         }
 292
 293         if (pkt->pfc_flags & DCERPC_PFC_FLAG_OBJECT_UUID) {
 294                 hdr_size += 16;
 295         }
 296
 297         switch (dce_conn->auth_state.auth_info->auth_level) {
 298         case DCERPC_AUTH_LEVEL_PRIVACY:
 299         case DCERPC_AUTH_LEVEL_INTEGRITY:
 300                 break;
 301
 302         case DCERPC_AUTH_LEVEL_CONNECT:
 303                 if (pkt->auth_length != 0) {
 304                         break;
 305                 }
 306                 return true;
 307         case DCERPC_AUTH_LEVEL_NONE:
 308                 if (pkt->auth_length != 0) {
 309                         return false;
 310                 }
 311                 return true;
 312
 313         default:
 314                 return false;
 315         }
 316
 317         status = dcerpc_pull_auth_trailer(pkt, call,
 318                                           &pkt->u.request.stub_and_verifier,
 319                                           &auth, &auth_length, false);
 320         if (!NT_STATUS_IS_OK(status)) {
 321                 return false;
 322         }
 323
 324         pkt->u.request.stub_and_verifier.length -= auth_length;
 325
 326         /* check signature or unseal the packet */
 327         switch (dce_conn->auth_state.auth_info->auth_level) {
 328         case DCERPC_AUTH_LEVEL_PRIVACY:
 329                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 330                                               call,
 331                                               full_packet->data + hdr_size,
 332                                               pkt->u.request.stub_and_verifier.length,
 333                                               full_packet->data,
 334                                               full_packet->length-auth.credentials.length,
 335                                               &auth.credentials);
 336                 memcpy(pkt->u.request.stub_and_verifier.data,
 337                        full_packet->data + hdr_size,
 338                        pkt->u.request.stub_and_verifier.length);
 339                 break;
 340
 341         case DCERPC_AUTH_LEVEL_INTEGRITY:
 342                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 343                                              call,
 344                                              pkt->u.request.stub_and_verifier.data,
 345                                              pkt->u.request.stub_and_verifier.length,
 346                                              full_packet->data,
 347                                              full_packet->length-auth.credentials.length,
 348                                              &auth.credentials);
 349                 break;
 350
 351         case DCERPC_AUTH_LEVEL_CONNECT:
 352                 /* for now we ignore possible signatures here */
 353                 status = NT_STATUS_OK;
 354                 break;
 355
 356         default:
 357                 status = NT_STATUS_INVALID_LEVEL;
 358                 break;
 359         }
 360
 361         /* remove the indicated amount of padding */
 362         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 363                 return false;
 364         }
 365         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 366
 367         return NT_STATUS_IS_OK(status);
 368 }
 369
 370
 371 /*
 372    push a signed or sealed dcerpc request packet into a blob
 373 */
 374 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 375                           DATA_BLOB *blob, size_t sig_size,
 376                           struct ncacn_packet *pkt)
 377 {
 378         struct dcesrv_connection *dce_conn = call->conn;
 379         NTSTATUS status;
 380         enum ndr_err_code ndr_err;
 381         struct ndr_push *ndr;
 382         uint32_t payload_length;
 383         DATA_BLOB creds2;
 384
 385         /* non-signed packets are simple */
 386         if (sig_size == 0) {
 387                 status = ncacn_push_auth(blob, call, pkt, NULL);
 388                 return NT_STATUS_IS_OK(status);
 389         }
 390
 391         switch (dce_conn->auth_state.auth_info->auth_level) {
 392         case DCERPC_AUTH_LEVEL_PRIVACY:
 393         case DCERPC_AUTH_LEVEL_INTEGRITY:
 394                 break;
 395
 396         case DCERPC_AUTH_LEVEL_CONNECT:
 397                 /*
 398                  * TODO: let the gensec mech decide if it wants to generate a
 399                  *       signature that might be needed for schannel...
 400                  */
 401                 status = ncacn_push_auth(blob, call, pkt, NULL);
 402                 return NT_STATUS_IS_OK(status);
 403
 404         case DCERPC_AUTH_LEVEL_NONE:
 405                 status = ncacn_push_auth(blob, call, pkt, NULL);
 406                 return NT_STATUS_IS_OK(status);
 407
 408         default:
 409                 return false;
 410         }
 411
 412         ndr = ndr_push_init_ctx(call);
 413         if (!ndr) {
 414                 return false;
 415         }
 416
 417         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 418                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 419         }
 420
 421         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 422         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 423                 return false;
 424         }
 425
 426         /* pad to 16 byte multiple in the payload portion of the
 427            packet. This matches what w2k3 does. Note that we can't use
 428            ndr_push_align() as that is relative to the start of the
 429            whole packet, whereas w2k8 wants it relative to the start
 430            of the stub */
 431         dce_conn->auth_state.auth_info->auth_pad_length =
 432                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 433         ndr_err = ndr_push_zero(ndr,
 434                                 dce_conn->auth_state.auth_info->auth_pad_length);
 435         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 436                 return false;
 437         }
 438
 439         payload_length = pkt->u.response.stub_and_verifier.length +
 440                 dce_conn->auth_state.auth_info->auth_pad_length;
 441
 442         /* we start without signature, it will appended later */
 443         dce_conn->auth_state.auth_info->credentials = data_blob(NULL, 0);
 444
 445         /* add the auth verifier */
 446         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 447                                        dce_conn->auth_state.auth_info);
 448         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 449                 return false;
 450         }
 451
 452         /* extract the whole packet as a blob */
 453         *blob = ndr_push_blob(ndr);
 454
 455         /*
 456          * Setup the frag and auth length in the packet buffer.
 457          * This is needed if the GENSEC mech does AEAD signing
 458          * of the packet headers. The signature itself will be
 459          * appended later.
 460          */
 461         dcerpc_set_frag_length(blob, blob->length + sig_size);
 462         dcerpc_set_auth_length(blob, sig_size);
 463
 464         /* sign or seal the packet */
 465         switch (dce_conn->auth_state.auth_info->auth_level) {
 466         case DCERPC_AUTH_LEVEL_PRIVACY:
 467                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 468                                             call,
 469                                             ndr->data + DCERPC_REQUEST_LENGTH,
 470                                             payload_length,
 471                                             blob->data,
 472                                             blob->length,
 473                                             &creds2);
 474                 break;
 475
 476         case DCERPC_AUTH_LEVEL_INTEGRITY:
 477                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 478                                             call,
 479                                             ndr->data + DCERPC_REQUEST_LENGTH,
 480                                             payload_length,
 481                                             blob->data,
 482                                             blob->length,
 483                                             &creds2);
 484                 break;
 485
 486         default:
 487                 status = NT_STATUS_INVALID_LEVEL;
 488                 break;
 489         }
 490
 491         if (!NT_STATUS_IS_OK(status)) {
 492                 return false;
 493         }
 494
 495         if (creds2.length != sig_size) {
 496                 DEBUG(3,("dcesrv_auth_response: creds2.length[%u] != sig_size[%u] pad[%u] stub[%u]\n",
 497                          (unsigned)creds2.length, (uint32_t)sig_size,
 498                          (unsigned)dce_conn->auth_state.auth_info->auth_pad_length,
 499                          (unsigned)pkt->u.response.stub_and_verifier.length));
 500                 dcerpc_set_frag_length(blob, blob->length + creds2.length);
 501                 dcerpc_set_auth_length(blob, creds2.length);
 502         }
 503
 504         if (!data_blob_append(call, blob, creds2.data, creds2.length)) {
 505                 status = NT_STATUS_NO_MEMORY;
 506                 return false;
 507         }
 508         data_blob_free(&creds2);
 509
 510         return true;
 511 }