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