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 "auth/auth.h"
  31 #include "param/param.h"
  32
  33 /*
  34   parse any auth information from a dcerpc bind request
  35   return false if we can't handle the auth request for some
  36   reason (in which case we send a bind_nak)
  37 */
  38 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
  39 {
  40         struct cli_credentials *server_credentials;
  41         struct ncacn_packet *pkt = &call->pkt;
  42         struct dcesrv_connection *dce_conn = call->conn;
  43         struct dcesrv_auth *auth = &dce_conn->auth_state;
  44         NTSTATUS status;
  45         uint32_t auth_length;
  46
  47         if (pkt->u.bind.auth_info.length == 0) {
  48                 dce_conn->auth_state.auth_info = NULL;
  49                 return true;
  50         }
  51
  52         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  53         if (!dce_conn->auth_state.auth_info) {
  54                 return false;
  55         }
  56
  57         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.bind.auth_info,
  58                                           dce_conn->auth_state.auth_info,
  59                                           &auth_length, false);
  60         server_credentials
  61                 = cli_credentials_init(call);
  62         if (!server_credentials) {
  63                 DEBUG(1, ("Failed to init server credentials\n"));
  64                 return false;
  65         }
  66
  67         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  68         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  69         if (!NT_STATUS_IS_OK(status)) {
  70                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  71                 talloc_free(server_credentials);
  72                 server_credentials = NULL;
  73         }
  74
  75         status = samba_server_gensec_start(dce_conn, call->event_ctx,
  76                                            call->msg_ctx,
  77                                            call->conn->dce_ctx->lp_ctx,
  78                                            server_credentials,
  79                                            NULL,
  80                                            &auth->gensec_security);
  81
  82         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  83                                                auth->auth_info->auth_level);
  84
  85         if (!NT_STATUS_IS_OK(status)) {
  86                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
  87                           (int)auth->auth_info->auth_type,
  88                           (int)auth->auth_info->auth_level,
  89                           nt_errstr(status)));
  90                 return false;
  91         }
  92
  93         if (call->conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
  94                 gensec_want_feature(auth->gensec_security, GENSEC_FEATURE_SIGN_PKT_HEADER);
  95         }
  96
  97         return true;
  98 }
  99
 100 /*
 101   add any auth information needed in a bind ack, and process the authentication
 102   information found in the bind.
 103 */
 104 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 105 {
 106         struct dcesrv_connection *dce_conn = call->conn;
 107         NTSTATUS status;
 108
 109         if (!call->conn->auth_state.gensec_security) {
 110                 return NT_STATUS_OK;
 111         }
 112
 113         status = gensec_update(dce_conn->auth_state.gensec_security,
 114                                call,
 115                                dce_conn->auth_state.auth_info->credentials,
 116                                &dce_conn->auth_state.auth_info->credentials);
 117
 118         if (NT_STATUS_IS_OK(status)) {
 119                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 120                                              &dce_conn->auth_state.session_info);
 121                 if (!NT_STATUS_IS_OK(status)) {
 122                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 123                         return status;
 124                 }
 125
 126                 if (dce_conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
 127                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 128                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 129                 }
 130
 131                 /* Now that we are authenticated, go back to the generic session key... */
 132                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 133                 return NT_STATUS_OK;
 134         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 135                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 136                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 137                 return NT_STATUS_OK;
 138         } else {
 139                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 140                 return status;
 141         }
 142 }
 143
 144
 145 /*
 146   process the final stage of a auth request
 147 */
 148 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 149 {
 150         struct ncacn_packet *pkt = &call->pkt;
 151         struct dcesrv_connection *dce_conn = call->conn;
 152         NTSTATUS status;
 153         uint32_t auth_length;
 154
 155         /* We can't work without an existing gensec state, and an new blob to feed it */
 156         if (!dce_conn->auth_state.auth_info ||
 157             !dce_conn->auth_state.gensec_security ||
 158             pkt->u.auth3.auth_info.length == 0) {
 159                 return false;
 160         }
 161
 162         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.auth3.auth_info,
 163                                           dce_conn->auth_state.auth_info, &auth_length, true);
 164         if (!NT_STATUS_IS_OK(status)) {
 165                 return false;
 166         }
 167
 168         /* Pass the extra data we got from the client down to gensec for processing */
 169         status = gensec_update(dce_conn->auth_state.gensec_security,
 170                                call,
 171                                dce_conn->auth_state.auth_info->credentials,
 172                                &dce_conn->auth_state.auth_info->credentials);
 173         if (NT_STATUS_IS_OK(status)) {
 174                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 175                                              &dce_conn->auth_state.session_info);
 176                 if (!NT_STATUS_IS_OK(status)) {
 177                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 178                         return false;
 179                 }
 180                 /* Now that we are authenticated, go back to the generic session key... */
 181                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 182                 return true;
 183         } else {
 184                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 185                           nt_errstr(status)));
 186                 return false;
 187         }
 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         NTSTATUS status;
 200         uint32_t auth_length;
 201
 202         /* on a pure interface change there is no auth blob */
 203         if (pkt->u.alter.auth_info.length == 0) {
 204                 return true;
 205         }
 206
 207         /* We can't work without an existing gensec state */
 208         if (!dce_conn->auth_state.gensec_security) {
 209                 return false;
 210         }
 211
 212         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 213         if (!dce_conn->auth_state.auth_info) {
 214                 return false;
 215         }
 216
 217         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.alter.auth_info,
 218                                           dce_conn->auth_state.auth_info,
 219                                           &auth_length, true);
 220         if (!NT_STATUS_IS_OK(status)) {
 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   check credentials on a request
 275 */
 276 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 277 {
 278         struct ncacn_packet *pkt = &call->pkt;
 279         struct dcesrv_connection *dce_conn = call->conn;
 280         struct dcerpc_auth auth;
 281         NTSTATUS status;
 282         uint32_t auth_length;
 283         size_t hdr_size = DCERPC_REQUEST_LENGTH;
 284
 285         if (!dce_conn->auth_state.auth_info ||
 286             !dce_conn->auth_state.gensec_security) {
 287                 return true;
 288         }
 289
 290         if (pkt->pfc_flags & DCERPC_PFC_FLAG_OBJECT_UUID) {
 291                 hdr_size += 16;
 292         }
 293
 294         switch (dce_conn->auth_state.auth_info->auth_level) {
 295         case DCERPC_AUTH_LEVEL_PRIVACY:
 296         case DCERPC_AUTH_LEVEL_INTEGRITY:
 297                 break;
 298
 299         case DCERPC_AUTH_LEVEL_CONNECT:
 300                 if (pkt->auth_length != 0) {
 301                         break;
 302                 }
 303                 return true;
 304         case DCERPC_AUTH_LEVEL_NONE:
 305                 if (pkt->auth_length != 0) {
 306                         return false;
 307                 }
 308                 return true;
 309
 310         default:
 311                 return false;
 312         }
 313
 314         status = dcerpc_pull_auth_trailer(pkt, call,
 315                                           &pkt->u.request.stub_and_verifier,
 316                                           &auth, &auth_length, false);
 317         if (!NT_STATUS_IS_OK(status)) {
 318                 return false;
 319         }
 320
 321         pkt->u.request.stub_and_verifier.length -= auth_length;
 322
 323         /* check signature or unseal the packet */
 324         switch (dce_conn->auth_state.auth_info->auth_level) {
 325         case DCERPC_AUTH_LEVEL_PRIVACY:
 326                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 327                                               call,
 328                                               full_packet->data + hdr_size,
 329                                               pkt->u.request.stub_and_verifier.length,
 330                                               full_packet->data,
 331                                               full_packet->length-auth.credentials.length,
 332                                               &auth.credentials);
 333                 memcpy(pkt->u.request.stub_and_verifier.data,
 334                        full_packet->data + hdr_size,
 335                        pkt->u.request.stub_and_verifier.length);
 336                 break;
 337
 338         case DCERPC_AUTH_LEVEL_INTEGRITY:
 339                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 340                                              call,
 341                                              pkt->u.request.stub_and_verifier.data,
 342                                              pkt->u.request.stub_and_verifier.length,
 343                                              full_packet->data,
 344                                              full_packet->length-auth.credentials.length,
 345                                              &auth.credentials);
 346                 break;
 347
 348         case DCERPC_AUTH_LEVEL_CONNECT:
 349                 /* for now we ignore possible signatures here */
 350                 status = NT_STATUS_OK;
 351                 break;
 352
 353         default:
 354                 status = NT_STATUS_INVALID_LEVEL;
 355                 break;
 356         }
 357
 358         /* remove the indicated amount of padding */
 359         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 360                 return false;
 361         }
 362         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 363
 364         return NT_STATUS_IS_OK(status);
 365 }
 366
 367
 368 /*
 369    push a signed or sealed dcerpc request packet into a blob
 370 */
 371 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 372                           DATA_BLOB *blob, size_t sig_size,
 373                           struct ncacn_packet *pkt)
 374 {
 375         struct dcesrv_connection *dce_conn = call->conn;
 376         NTSTATUS status;
 377         enum ndr_err_code ndr_err;
 378         struct ndr_push *ndr;
 379         uint32_t payload_length;
 380         DATA_BLOB creds2;
 381
 382         /* non-signed packets are simple */
 383         if (sig_size == 0) {
 384                 status = ncacn_push_auth(blob, call, pkt, NULL);
 385                 return NT_STATUS_IS_OK(status);
 386         }
 387
 388         switch (dce_conn->auth_state.auth_info->auth_level) {
 389         case DCERPC_AUTH_LEVEL_PRIVACY:
 390         case DCERPC_AUTH_LEVEL_INTEGRITY:
 391                 break;
 392
 393         case DCERPC_AUTH_LEVEL_CONNECT:
 394                 /*
 395                  * TODO: let the gensec mech decide if it wants to generate a signature
 396                  *       that might be needed for schannel...
 397                  */
 398                 status = ncacn_push_auth(blob, call, pkt, NULL);
 399                 return NT_STATUS_IS_OK(status);
 400
 401         case DCERPC_AUTH_LEVEL_NONE:
 402                 status = ncacn_push_auth(blob, call, pkt, NULL);
 403                 return NT_STATUS_IS_OK(status);
 404
 405         default:
 406                 return false;
 407         }
 408
 409         ndr = ndr_push_init_ctx(call);
 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 in the payload portion of the
 424            packet. This matches what w2k3 does. Note that we can't use
 425            ndr_push_align() as that is relative to the start of the
 426            whole packet, whereas w2k8 wants it relative to the start
 427            of the stub */
 428         dce_conn->auth_state.auth_info->auth_pad_length =
 429                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 430         ndr_err = ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 431         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 432                 return false;
 433         }
 434
 435         payload_length = pkt->u.response.stub_and_verifier.length +
 436                 dce_conn->auth_state.auth_info->auth_pad_length;
 437
 438         /* we start without signature, it will appended later */
 439         dce_conn->auth_state.auth_info->credentials = data_blob(NULL, 0);
 440
 441         /* add the auth verifier */
 442         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 443                                       dce_conn->auth_state.auth_info);
 444         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 445                 return false;
 446         }
 447
 448         /* extract the whole packet as a blob */
 449         *blob = ndr_push_blob(ndr);
 450
 451         /*
 452          * Setup the frag and auth length in the packet buffer.
 453          * This is needed if the GENSEC mech does AEAD signing
 454          * of the packet headers. The signature itself will be
 455          * appended later.
 456          */
 457         dcerpc_set_frag_length(blob, blob->length + sig_size);
 458         dcerpc_set_auth_length(blob, sig_size);
 459
 460         /* sign or seal the packet */
 461         switch (dce_conn->auth_state.auth_info->auth_level) {
 462         case DCERPC_AUTH_LEVEL_PRIVACY:
 463                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 464                                             call,
 465                                             ndr->data + DCERPC_REQUEST_LENGTH,
 466                                             payload_length,
 467                                             blob->data,
 468                                             blob->length,
 469                                             &creds2);
 470                 break;
 471
 472         case DCERPC_AUTH_LEVEL_INTEGRITY:
 473                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 474                                             call,
 475                                             ndr->data + DCERPC_REQUEST_LENGTH,
 476                                             payload_length,
 477                                             blob->data,
 478                                             blob->length,
 479                                             &creds2);
 480                 break;
 481
 482         default:
 483                 status = NT_STATUS_INVALID_LEVEL;
 484                 break;
 485         }
 486
 487         if (!NT_STATUS_IS_OK(status)) {
 488                 return false;
 489         }
 490
 491         if (creds2.length != sig_size) {
 492                 DEBUG(3,("dcesrv_auth_response: creds2.length[%u] != sig_size[%u] pad[%u] stub[%u]\n",
 493                          (unsigned)creds2.length, (uint32_t)sig_size,
 494                          (unsigned)dce_conn->auth_state.auth_info->auth_pad_length,
 495                          (unsigned)pkt->u.response.stub_and_verifier.length));
 496                 dcerpc_set_frag_length(blob, blob->length + creds2.length);
 497                 dcerpc_set_auth_length(blob, creds2.length);
 498         }
 499
 500         if (!data_blob_append(call, blob, creds2.data, creds2.length)) {
 501                 status = NT_STATUS_NO_MEMORY;
 502                 return false;
 503         }
 504         data_blob_free(&creds2);
 505
 506         return true;
 507 }