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 #include "librpc/rpc/rpc_common.h"
  34
  35 /*
  36   parse any auth information from a dcerpc bind request
  37   return false if we can't handle the auth request for some
  38   reason (in which case we send a bind_nak)
  39 */
  40 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
  41 {
  42         struct cli_credentials *server_credentials;
  43         struct ncacn_packet *pkt = &call->pkt;
  44         struct dcesrv_connection *dce_conn = call->conn;
  45         struct dcesrv_auth *auth = &dce_conn->auth_state;
  46         NTSTATUS status;
  47         uint32_t auth_length;
  48
  49         if (pkt->u.bind.auth_info.length == 0) {
  50                 dce_conn->auth_state.auth_info = NULL;
  51                 return true;
  52         }
  53
  54         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  55         if (!dce_conn->auth_state.auth_info) {
  56                 return false;
  57         }
  58
  59         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.bind.auth_info,
  60                                           dce_conn->auth_state.auth_info,
  61                                           &auth_length, false);
  62         server_credentials
  63                 = cli_credentials_init(call);
  64         if (!server_credentials) {
  65                 DEBUG(1, ("Failed to init server credentials\n"));
  66                 return false;
  67         }
  68
  69         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  70         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  71         if (!NT_STATUS_IS_OK(status)) {
  72                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  73                 talloc_free(server_credentials);
  74                 server_credentials = NULL;
  75         }
  76
  77         status = samba_server_gensec_start(dce_conn, call->event_ctx,
  78                                            call->msg_ctx,
  79                                            call->conn->dce_ctx->lp_ctx,
  80                                            server_credentials,
  81                                            NULL,
  82                                            &auth->gensec_security);
  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(3, ("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         if (call->conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
  96                 gensec_want_feature(auth->gensec_security, GENSEC_FEATURE_SIGN_PKT_HEADER);
  97         }
  98
  99         return true;
 100 }
 101
 102 /*
 103   add any auth information needed in a bind ack, and process the authentication
 104   information found in the bind.
 105 */
 106 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 107 {
 108         struct dcesrv_connection *dce_conn = call->conn;
 109         NTSTATUS status;
 110
 111         if (!call->conn->auth_state.gensec_security) {
 112                 return NT_STATUS_OK;
 113         }
 114
 115         status = gensec_update(dce_conn->auth_state.gensec_security,
 116                                call,
 117                                dce_conn->auth_state.auth_info->credentials,
 118                                &dce_conn->auth_state.auth_info->credentials);
 119
 120         if (NT_STATUS_IS_OK(status)) {
 121                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 122                                              &dce_conn->auth_state.session_info);
 123                 if (!NT_STATUS_IS_OK(status)) {
 124                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 125                         return status;
 126                 }
 127
 128                 if (dce_conn->state_flags & DCESRV_CALL_STATE_FLAG_HEADER_SIGNING) {
 129                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 130                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 131                 }
 132
 133                 /* Now that we are authenticated, go back to the generic session key... */
 134                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 135                 return NT_STATUS_OK;
 136         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 137                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 138                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 139                 return NT_STATUS_OK;
 140         } else {
 141                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_ack: %s\n",
 142                           nt_errstr(status)));
 143                 return status;
 144         }
 145 }
 146
 147
 148 /*
 149   process the final stage of a auth request
 150 */
 151 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 152 {
 153         struct ncacn_packet *pkt = &call->pkt;
 154         struct dcesrv_connection *dce_conn = call->conn;
 155         NTSTATUS status;
 156         uint32_t auth_length;
 157
 158         /* We can't work without an existing gensec state, and an new blob to feed it */
 159         if (!dce_conn->auth_state.auth_info ||
 160             !dce_conn->auth_state.gensec_security ||
 161             pkt->u.auth3.auth_info.length == 0) {
 162                 return false;
 163         }
 164
 165         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.auth3.auth_info,
 166                                           dce_conn->auth_state.auth_info, &auth_length, true);
 167         if (!NT_STATUS_IS_OK(status)) {
 168                 return false;
 169         }
 170
 171         /* Pass the extra data we got from the client down to gensec for processing */
 172         status = gensec_update(dce_conn->auth_state.gensec_security,
 173                                call,
 174                                dce_conn->auth_state.auth_info->credentials,
 175                                &dce_conn->auth_state.auth_info->credentials);
 176         if (NT_STATUS_IS_OK(status)) {
 177                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 178                                              &dce_conn->auth_state.session_info);
 179                 if (!NT_STATUS_IS_OK(status)) {
 180                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 181                         return false;
 182                 }
 183                 /* Now that we are authenticated, go back to the generic session key... */
 184                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 185                 return true;
 186         } else {
 187                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_auth3: %s\n",
 188                           nt_errstr(status)));
 189                 return false;
 190         }
 191 }
 192
 193 /*
 194   parse any auth information from a dcerpc alter request
 195   return false if we can't handle the auth request for some
 196   reason (in which case we send a bind_nak (is this true for here?))
 197 */
 198 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 199 {
 200         struct ncacn_packet *pkt = &call->pkt;
 201         struct dcesrv_connection *dce_conn = call->conn;
 202         NTSTATUS status;
 203         uint32_t auth_length;
 204
 205         /* on a pure interface change there is no auth blob */
 206         if (pkt->u.alter.auth_info.length == 0) {
 207                 return true;
 208         }
 209
 210         /* We can't work without an existing gensec state */
 211         if (!dce_conn->auth_state.gensec_security) {
 212                 return false;
 213         }
 214
 215         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 216         if (!dce_conn->auth_state.auth_info) {
 217                 return false;
 218         }
 219
 220         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.alter.auth_info,
 221                                           dce_conn->auth_state.auth_info,
 222                                           &auth_length, true);
 223         if (!NT_STATUS_IS_OK(status)) {
 224                 return false;
 225         }
 226
 227         return true;
 228 }
 229
 230 /*
 231   add any auth information needed in a alter ack, and process the authentication
 232   information found in the alter.
 233 */
 234 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 235 {
 236         struct dcesrv_connection *dce_conn = call->conn;
 237         NTSTATUS status;
 238
 239         /* on a pure interface change there is no auth_info structure
 240            setup */
 241         if (!call->conn->auth_state.auth_info ||
 242             dce_conn->auth_state.auth_info->credentials.length == 0) {
 243                 return NT_STATUS_OK;
 244         }
 245
 246         if (!call->conn->auth_state.gensec_security) {
 247                 return NT_STATUS_INVALID_PARAMETER;
 248         }
 249
 250         status = gensec_update(dce_conn->auth_state.gensec_security,
 251                                call,
 252                                dce_conn->auth_state.auth_info->credentials,
 253                                &dce_conn->auth_state.auth_info->credentials);
 254
 255         if (NT_STATUS_IS_OK(status)) {
 256                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 257                                              &dce_conn->auth_state.session_info);
 258                 if (!NT_STATUS_IS_OK(status)) {
 259                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 260                         return status;
 261                 }
 262
 263                 /* Now that we are authenticated, got back to the generic session key... */
 264                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 265                 return NT_STATUS_OK;
 266         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 267                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 268                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 269                 return NT_STATUS_OK;
 270         }
 271
 272         DEBUG(4, ("GENSEC mech rejected the incoming authentication at auth alter_ack: %s\n",
 273                   nt_errstr(status)));
 274         return status;
 275 }
 276
 277 /*
 278   check credentials on a request
 279 */
 280 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 281 {
 282         struct ncacn_packet *pkt = &call->pkt;
 283         struct dcesrv_connection *dce_conn = call->conn;
 284         struct dcerpc_auth auth;
 285         NTSTATUS status;
 286         uint32_t auth_length;
 287         size_t hdr_size = DCERPC_REQUEST_LENGTH;
 288
 289         if (!dce_conn->auth_state.auth_info ||
 290             !dce_conn->auth_state.gensec_security) {
 291                 return true;
 292         }
 293
 294         if (pkt->pfc_flags & DCERPC_PFC_FLAG_OBJECT_UUID) {
 295                 hdr_size += 16;
 296         }
 297
 298         switch (dce_conn->auth_state.auth_info->auth_level) {
 299         case DCERPC_AUTH_LEVEL_PRIVACY:
 300         case DCERPC_AUTH_LEVEL_INTEGRITY:
 301                 break;
 302
 303         case DCERPC_AUTH_LEVEL_CONNECT:
 304                 if (pkt->auth_length != 0) {
 305                         break;
 306                 }
 307                 return true;
 308         case DCERPC_AUTH_LEVEL_NONE:
 309                 if (pkt->auth_length != 0) {
 310                         return false;
 311                 }
 312                 return true;
 313
 314         default:
 315                 return false;
 316         }
 317
 318         status = dcerpc_pull_auth_trailer(pkt, call,
 319                                           &pkt->u.request.stub_and_verifier,
 320                                           &auth, &auth_length, false);
 321         if (!NT_STATUS_IS_OK(status)) {
 322                 return false;
 323         }
 324
 325         pkt->u.request.stub_and_verifier.length -= auth_length;
 326
 327         /* check signature or unseal the packet */
 328         switch (dce_conn->auth_state.auth_info->auth_level) {
 329         case DCERPC_AUTH_LEVEL_PRIVACY:
 330                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 331                                               call,
 332                                               full_packet->data + hdr_size,
 333                                               pkt->u.request.stub_and_verifier.length,
 334                                               full_packet->data,
 335                                               full_packet->length-auth.credentials.length,
 336                                               &auth.credentials);
 337                 memcpy(pkt->u.request.stub_and_verifier.data,
 338                        full_packet->data + hdr_size,
 339                        pkt->u.request.stub_and_verifier.length);
 340                 break;
 341
 342         case DCERPC_AUTH_LEVEL_INTEGRITY:
 343                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 344                                              call,
 345                                              pkt->u.request.stub_and_verifier.data,
 346                                              pkt->u.request.stub_and_verifier.length,
 347                                              full_packet->data,
 348                                              full_packet->length-auth.credentials.length,
 349                                              &auth.credentials);
 350                 break;
 351
 352         case DCERPC_AUTH_LEVEL_CONNECT:
 353                 /* for now we ignore possible signatures here */
 354                 status = NT_STATUS_OK;
 355                 break;
 356
 357         default:
 358                 status = NT_STATUS_INVALID_LEVEL;
 359                 break;
 360         }
 361
 362         /* remove the indicated amount of padding */
 363         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 364                 return false;
 365         }
 366         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 367
 368         return NT_STATUS_IS_OK(status);
 369 }
 370
 371
 372 /*
 373    push a signed or sealed dcerpc request packet into a blob
 374 */
 375 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 376                           DATA_BLOB *blob, size_t sig_size,
 377                           struct ncacn_packet *pkt)
 378 {
 379         struct dcesrv_connection *dce_conn = call->conn;
 380         NTSTATUS status;
 381         enum ndr_err_code ndr_err;
 382         struct ndr_push *ndr;
 383         uint32_t payload_length;
 384         DATA_BLOB creds2;
 385
 386         /* non-signed packets are simple */
 387         if (sig_size == 0) {
 388                 status = ncacn_push_auth(blob, call, pkt, NULL);
 389                 return NT_STATUS_IS_OK(status);
 390         }
 391
 392         switch (dce_conn->auth_state.auth_info->auth_level) {
 393         case DCERPC_AUTH_LEVEL_PRIVACY:
 394         case DCERPC_AUTH_LEVEL_INTEGRITY:
 395                 break;
 396
 397         case DCERPC_AUTH_LEVEL_CONNECT:
 398                 /*
 399                  * TODO: let the gensec mech decide if it wants to generate a
 400                  *       signature that might be needed for schannel...
 401                  */
 402                 status = ncacn_push_auth(blob, call, pkt, NULL);
 403                 return NT_STATUS_IS_OK(status);
 404
 405         case DCERPC_AUTH_LEVEL_NONE:
 406                 status = ncacn_push_auth(blob, call, pkt, NULL);
 407                 return NT_STATUS_IS_OK(status);
 408
 409         default:
 410                 return false;
 411         }
 412
 413         ndr = ndr_push_init_ctx(call);
 414         if (!ndr) {
 415                 return false;
 416         }
 417
 418         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 419                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 420         }
 421
 422         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 423         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 424                 return false;
 425         }
 426
 427         /* pad to 16 byte multiple in the payload portion of the
 428            packet. This matches what w2k3 does. Note that we can't use
 429            ndr_push_align() as that is relative to the start of the
 430            whole packet, whereas w2k8 wants it relative to the start
 431            of the stub */
 432         dce_conn->auth_state.auth_info->auth_pad_length =
 433                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 434         ndr_err = ndr_push_zero(ndr,
 435                                 dce_conn->auth_state.auth_info->auth_pad_length);
 436         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 437                 return false;
 438         }
 439
 440         payload_length = pkt->u.response.stub_and_verifier.length +
 441                 dce_conn->auth_state.auth_info->auth_pad_length;
 442
 443         /* we start without signature, it will appended later */
 444         dce_conn->auth_state.auth_info->credentials = data_blob(NULL, 0);
 445
 446         /* add the auth verifier */
 447         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 448                                        dce_conn->auth_state.auth_info);
 449         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 450                 return false;
 451         }
 452
 453         /* extract the whole packet as a blob */
 454         *blob = ndr_push_blob(ndr);
 455
 456         /*
 457          * Setup the frag and auth length in the packet buffer.
 458          * This is needed if the GENSEC mech does AEAD signing
 459          * of the packet headers. The signature itself will be
 460          * appended later.
 461          */
 462         dcerpc_set_frag_length(blob, blob->length + sig_size);
 463         dcerpc_set_auth_length(blob, sig_size);
 464
 465         /* sign or seal the packet */
 466         switch (dce_conn->auth_state.auth_info->auth_level) {
 467         case DCERPC_AUTH_LEVEL_PRIVACY:
 468                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 469                                             call,
 470                                             ndr->data + DCERPC_REQUEST_LENGTH,
 471                                             payload_length,
 472                                             blob->data,
 473                                             blob->length,
 474                                             &creds2);
 475                 break;
 476
 477         case DCERPC_AUTH_LEVEL_INTEGRITY:
 478                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 479                                             call,
 480                                             ndr->data + DCERPC_REQUEST_LENGTH,
 481                                             payload_length,
 482                                             blob->data,
 483                                             blob->length,
 484                                             &creds2);
 485                 break;
 486
 487         default:
 488                 status = NT_STATUS_INVALID_LEVEL;
 489                 break;
 490         }
 491
 492         if (!NT_STATUS_IS_OK(status)) {
 493                 return false;
 494         }
 495
 496         if (creds2.length != sig_size) {
 497                 DEBUG(3,("dcesrv_auth_response: creds2.length[%u] != sig_size[%u] pad[%u] stub[%u]\n",
 498                          (unsigned)creds2.length, (uint32_t)sig_size,
 499                          (unsigned)dce_conn->auth_state.auth_info->auth_pad_length,
 500                          (unsigned)pkt->u.response.stub_and_verifier.length));
 501                 dcerpc_set_frag_length(blob, blob->length + creds2.length);
 502                 dcerpc_set_auth_length(blob, creds2.length);
 503         }
 504
 505         if (!data_blob_append(call, blob, creds2.data, creds2.length)) {
 506                 status = NT_STATUS_NO_MEMORY;
 507                 return false;
 508         }
 509         data_blob_free(&creds2);
 510
 511         return true;
 512 }