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 "param/param.h"
  31
  32 /*
  33   parse any auth information from a dcerpc bind request
  34   return false if we can't handle the auth request for some
  35   reason (in which case we send a bind_nak)
  36 */
  37 bool dcesrv_auth_bind(struct dcesrv_call_state *call)
  38 {
  39         struct cli_credentials *server_credentials;
  40         struct ncacn_packet *pkt = &call->pkt;
  41         struct dcesrv_connection *dce_conn = call->conn;
  42         struct dcesrv_auth *auth = &dce_conn->auth_state;
  43         NTSTATUS status;
  44         enum ndr_err_code ndr_err;
  45
  46         if (pkt->u.bind.auth_info.length == 0) {
  47                 dce_conn->auth_state.auth_info = NULL;
  48                 return true;
  49         }
  50
  51         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  52         if (!dce_conn->auth_state.auth_info) {
  53                 return false;
  54         }
  55
  56         ndr_err = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
  57                                        call, NULL,
  58                                        dce_conn->auth_state.auth_info,
  59                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
  60         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  61                 return false;
  62         }
  63
  64         status = gensec_server_start(dce_conn, call->event_ctx, call->conn->dce_ctx->lp_ctx, call->msg_ctx, &auth->gensec_security);
  65         if (!NT_STATUS_IS_OK(status)) {
  66                 DEBUG(1, ("Failed to start GENSEC for DCERPC server: %s\n", nt_errstr(status)));
  67                 return false;
  68         }
  69
  70         server_credentials
  71                 = cli_credentials_init(call);
  72         if (!server_credentials) {
  73                 DEBUG(1, ("Failed to init server credentials\n"));
  74                 return false;
  75         }
  76
  77         cli_credentials_set_conf(server_credentials, call->conn->dce_ctx->lp_ctx);
  78         status = cli_credentials_set_machine_account(server_credentials, call->conn->dce_ctx->lp_ctx);
  79         if (!NT_STATUS_IS_OK(status)) {
  80                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  81                 talloc_free(server_credentials);
  82                 server_credentials = NULL;
  83         }
  84
  85         gensec_set_credentials(auth->gensec_security, server_credentials);
  86
  87         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  88                                                auth->auth_info->auth_level);
  89
  90         if (!NT_STATUS_IS_OK(status)) {
  91                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
  92                           (int)auth->auth_info->auth_type,
  93                           (int)auth->auth_info->auth_level,
  94                           nt_errstr(status)));
  95                 return false;
  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(2, ("Failed to start dcesrv auth negotiate: %s\n", 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         enum ndr_err_code ndr_err;
 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         ndr_err = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 164                                        call, NULL,
 165                                        dce_conn->auth_state.auth_info,
 166                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 167         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 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, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 188                           nt_errstr(status)));
 189                 return false;
 190         }
 191
 192         return true;
 193 }
 194
 195 /*
 196   parse any auth information from a dcerpc alter request
 197   return false if we can't handle the auth request for some
 198   reason (in which case we send a bind_nak (is this true for here?))
 199 */
 200 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 201 {
 202         struct ncacn_packet *pkt = &call->pkt;
 203         struct dcesrv_connection *dce_conn = call->conn;
 204         enum ndr_err_code ndr_err;
 205
 206         /* on a pure interface change there is no auth blob */
 207         if (pkt->u.alter.auth_info.length == 0) {
 208                 return true;
 209         }
 210
 211         /* We can't work without an existing gensec state */
 212         if (!dce_conn->auth_state.gensec_security) {
 213                 return false;
 214         }
 215
 216         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 217         if (!dce_conn->auth_state.auth_info) {
 218                 return false;
 219         }
 220
 221         ndr_err = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 222                                        call, NULL,
 223                                        dce_conn->auth_state.auth_info,
 224                                        (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 225         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 226                 return false;
 227         }
 228
 229         return true;
 230 }
 231
 232 /*
 233   add any auth information needed in a alter ack, and process the authentication
 234   information found in the alter.
 235 */
 236 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 237 {
 238         struct dcesrv_connection *dce_conn = call->conn;
 239         NTSTATUS status;
 240
 241         /* on a pure interface change there is no auth_info structure
 242            setup */
 243         if (!call->conn->auth_state.auth_info ||
 244             dce_conn->auth_state.auth_info->credentials.length == 0) {
 245                 return NT_STATUS_OK;
 246         }
 247
 248         if (!call->conn->auth_state.gensec_security) {
 249                 return NT_STATUS_INVALID_PARAMETER;
 250         }
 251
 252         status = gensec_update(dce_conn->auth_state.gensec_security,
 253                                call,
 254                                dce_conn->auth_state.auth_info->credentials,
 255                                &dce_conn->auth_state.auth_info->credentials);
 256
 257         if (NT_STATUS_IS_OK(status)) {
 258                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 259                                              &dce_conn->auth_state.session_info);
 260                 if (!NT_STATUS_IS_OK(status)) {
 261                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 262                         return status;
 263                 }
 264
 265                 /* Now that we are authenticated, got back to the generic session key... */
 266                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 267                 return NT_STATUS_OK;
 268         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 269                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 270                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 271                 return NT_STATUS_OK;
 272         }
 273
 274         DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 275         return status;
 276 }
 277
 278 /*
 279   check credentials on a request
 280 */
 281 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 282 {
 283         struct ncacn_packet *pkt = &call->pkt;
 284         struct dcesrv_connection *dce_conn = call->conn;
 285         DATA_BLOB auth_blob;
 286         struct dcerpc_auth auth;
 287         struct ndr_pull *ndr;
 288         NTSTATUS status;
 289         enum ndr_err_code ndr_err;
 290
 291         if (!dce_conn->auth_state.auth_info ||
 292             !dce_conn->auth_state.gensec_security) {
 293                 return true;
 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         auth_blob.length = 8 + pkt->auth_length;
 317
 318         /* check for a valid length */
 319         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 320                 return false;
 321         }
 322
 323         auth_blob.data =
 324                 pkt->u.request.stub_and_verifier.data +
 325                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 326         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 327
 328         /* pull the auth structure */
 329         ndr = ndr_pull_init_blob(&auth_blob, call, lp_iconv_convenience(call->conn->dce_ctx->lp_ctx));
 330         if (!ndr) {
 331                 return false;
 332         }
 333
 334         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 335                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 336         }
 337
 338         ndr_err = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 339         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 340                 talloc_free(ndr);
 341                 return false;
 342         }
 343
 344         /* check signature or unseal the packet */
 345         switch (dce_conn->auth_state.auth_info->auth_level) {
 346         case DCERPC_AUTH_LEVEL_PRIVACY:
 347                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 348                                               call,
 349                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 350                                               pkt->u.request.stub_and_verifier.length,
 351                                               full_packet->data,
 352                                               full_packet->length-auth.credentials.length,
 353                                               &auth.credentials);
 354                 memcpy(pkt->u.request.stub_and_verifier.data,
 355                        full_packet->data + DCERPC_REQUEST_LENGTH,
 356                        pkt->u.request.stub_and_verifier.length);
 357                 break;
 358
 359         case DCERPC_AUTH_LEVEL_INTEGRITY:
 360                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 361                                              call,
 362                                              pkt->u.request.stub_and_verifier.data,
 363                                              pkt->u.request.stub_and_verifier.length,
 364                                              full_packet->data,
 365                                              full_packet->length-auth.credentials.length,
 366                                              &auth.credentials);
 367                 break;
 368
 369         case DCERPC_AUTH_LEVEL_CONNECT:
 370                 /* for now we ignore possible signatures here */
 371                 status = NT_STATUS_OK;
 372                 break;
 373
 374         default:
 375                 status = NT_STATUS_INVALID_LEVEL;
 376                 break;
 377         }
 378
 379         /* remove the indicated amount of padding */
 380         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 381                 talloc_free(ndr);
 382                 return false;
 383         }
 384         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 385         talloc_free(ndr);
 386
 387         return NT_STATUS_IS_OK(status);
 388 }
 389
 390
 391 /*
 392    push a signed or sealed dcerpc request packet into a blob
 393 */
 394 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 395                           DATA_BLOB *blob, size_t sig_size,
 396                           struct ncacn_packet *pkt)
 397 {
 398         struct dcesrv_connection *dce_conn = call->conn;
 399         NTSTATUS status;
 400         enum ndr_err_code ndr_err;
 401         struct ndr_push *ndr;
 402         uint32_t payload_length;
 403         DATA_BLOB creds2;
 404
 405         /* non-signed packets are simple */
 406         if (sig_size == 0) {
 407                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 408                 return NT_STATUS_IS_OK(status);
 409         }
 410
 411         switch (dce_conn->auth_state.auth_info->auth_level) {
 412         case DCERPC_AUTH_LEVEL_PRIVACY:
 413         case DCERPC_AUTH_LEVEL_INTEGRITY:
 414                 break;
 415
 416         case DCERPC_AUTH_LEVEL_CONNECT:
 417                 /*
 418                  * TODO: let the gensec mech decide if it wants to generate a signature
 419                  *       that might be needed for schannel...
 420                  */
 421                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 422                 return NT_STATUS_IS_OK(status);
 423
 424         case DCERPC_AUTH_LEVEL_NONE:
 425                 status = ncacn_push_auth(blob, call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx), pkt, NULL);
 426                 return NT_STATUS_IS_OK(status);
 427
 428         default:
 429                 return false;
 430         }
 431
 432         ndr = ndr_push_init_ctx(call, lp_iconv_convenience(dce_conn->dce_ctx->lp_ctx));
 433         if (!ndr) {
 434                 return false;
 435         }
 436
 437         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 438                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 439         }
 440
 441         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 442         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 443                 return false;
 444         }
 445
 446         /* pad to 16 byte multiple, match win2k3 */
 447         dce_conn->auth_state.auth_info->auth_pad_length =
 448                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 449         ndr_err = ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 450         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 451                 return false;
 452         }
 453
 454         payload_length = pkt->u.response.stub_and_verifier.length +
 455                 dce_conn->auth_state.auth_info->auth_pad_length;
 456
 457         /* we start without signature, it will appended later */
 458         dce_conn->auth_state.auth_info->credentials = data_blob(NULL, 0);
 459
 460         /* add the auth verifier */
 461         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 462                                       dce_conn->auth_state.auth_info);
 463         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 464                 return false;
 465         }
 466
 467         /* extract the whole packet as a blob */
 468         *blob = ndr_push_blob(ndr);
 469
 470         /*
 471          * Setup the frag and auth length in the packet buffer.
 472          * This is needed if the GENSEC mech does AEAD signing
 473          * of the packet headers. The signature itself will be
 474          * appended later.
 475          */
 476         dcerpc_set_frag_length(blob, blob->length + sig_size);
 477         dcerpc_set_auth_length(blob, sig_size);
 478
 479         /* sign or seal the packet */
 480         switch (dce_conn->auth_state.auth_info->auth_level) {
 481         case DCERPC_AUTH_LEVEL_PRIVACY:
 482                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 483                                             call,
 484                                             ndr->data + DCERPC_REQUEST_LENGTH,
 485                                             payload_length,
 486                                             blob->data,
 487                                             blob->length,
 488                                             &creds2);
 489                 break;
 490
 491         case DCERPC_AUTH_LEVEL_INTEGRITY:
 492                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 493                                             call,
 494                                             ndr->data + DCERPC_REQUEST_LENGTH,
 495                                             payload_length,
 496                                             blob->data,
 497                                             blob->length,
 498                                             &creds2);
 499                 break;
 500
 501         default:
 502                 status = NT_STATUS_INVALID_LEVEL;
 503                 break;
 504         }
 505
 506         if (NT_STATUS_IS_OK(status)) {
 507                 if (creds2.length != sig_size) {
 508                         DEBUG(0,("dcesrv_auth_response: creds2.length[%u] != sig_size[%u] pad[%u] stub[%u]\n",
 509                                 creds2.length, (uint32_t)sig_size,
 510                                 dce_conn->auth_state.auth_info->auth_pad_length,
 511                                 pkt->u.response.stub_and_verifier.length));
 512                         data_blob_free(&creds2);
 513                         status = NT_STATUS_INTERNAL_ERROR;
 514                 }
 515         }
 516
 517         if (NT_STATUS_IS_OK(status)) {
 518                 if (!data_blob_append(call, blob, creds2.data, creds2.length)) {
 519                         status = NT_STATUS_NO_MEMORY;
 520                 }
 521                 data_blob_free(&creds2);
 522         }
 523
 524         if (!NT_STATUS_IS_OK(status)) {
 525                 return false;
 526         }
 527
 528         return true;
 529 }