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         return true;
  96 }
  97
  98 /*
  99   add any auth information needed in a bind ack, and process the authentication
 100   information found in the bind.
 101 */
 102 NTSTATUS dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 103 {
 104         struct dcesrv_connection *dce_conn = call->conn;
 105         NTSTATUS status;
 106         bool want_header_signing = false;
 107
 108         if (!call->conn->auth_state.gensec_security) {
 109                 return NT_STATUS_OK;
 110         }
 111
 112         if (call->pkt.pfc_flags & DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN) {
 113                 want_header_signing = true;
 114         }
 115
 116         if (!lpcfg_parm_bool(call->conn->dce_ctx->lp_ctx, NULL, "dcesrv","header signing", true)) {
 117                 want_header_signing = false;
 118         }
 119
 120         status = gensec_update(dce_conn->auth_state.gensec_security,
 121                                call, call->event_ctx,
 122                                dce_conn->auth_state.auth_info->credentials,
 123                                &dce_conn->auth_state.auth_info->credentials);
 124
 125         if (NT_STATUS_IS_OK(status)) {
 126                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 127                                              dce_conn,
 128                                              &dce_conn->auth_state.session_info);
 129                 if (!NT_STATUS_IS_OK(status)) {
 130                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 131                         return status;
 132                 }
 133
 134                 if (!gensec_have_feature(dce_conn->auth_state.gensec_security,
 135                                          GENSEC_FEATURE_SIGN_PKT_HEADER))
 136                 {
 137                         want_header_signing = false;
 138                 }
 139
 140                 if (want_header_signing) {
 141                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 142                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 143                         call->conn->state_flags |= DCESRV_CALL_STATE_FLAG_HEADER_SIGNING;
 144                         pkt->pfc_flags |= DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN;
 145                 }
 146
 147                 /* Now that we are authenticated, go back to the generic session key... */
 148                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 149                 return NT_STATUS_OK;
 150         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 151                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 152                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 153
 154                 if (!gensec_have_feature(dce_conn->auth_state.gensec_security,
 155                                          GENSEC_FEATURE_SIGN_PKT_HEADER))
 156                 {
 157                         want_header_signing = false;
 158                 }
 159
 160                 if (want_header_signing) {
 161                         gensec_want_feature(dce_conn->auth_state.gensec_security,
 162                                             GENSEC_FEATURE_SIGN_PKT_HEADER);
 163                         call->conn->state_flags |= DCESRV_CALL_STATE_FLAG_HEADER_SIGNING;
 164                         pkt->pfc_flags |= DCERPC_PFC_FLAG_SUPPORT_HEADER_SIGN;
 165                 }
 166
 167                 return NT_STATUS_OK;
 168         } else {
 169                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_ack: %s\n",
 170                           nt_errstr(status)));
 171                 return status;
 172         }
 173 }
 174
 175
 176 /*
 177   process the final stage of a auth request
 178 */
 179 bool dcesrv_auth_auth3(struct dcesrv_call_state *call)
 180 {
 181         struct ncacn_packet *pkt = &call->pkt;
 182         struct dcesrv_connection *dce_conn = call->conn;
 183         NTSTATUS status;
 184         uint32_t auth_length;
 185
 186         /* We can't work without an existing gensec state, and an new blob to feed it */
 187         if (!dce_conn->auth_state.auth_info ||
 188             !dce_conn->auth_state.gensec_security ||
 189             pkt->u.auth3.auth_info.length == 0) {
 190                 return false;
 191         }
 192
 193         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.auth3.auth_info,
 194                                           dce_conn->auth_state.auth_info, &auth_length, true);
 195         if (!NT_STATUS_IS_OK(status)) {
 196                 return false;
 197         }
 198
 199         /* Pass the extra data we got from the client down to gensec for processing */
 200         status = gensec_update(dce_conn->auth_state.gensec_security,
 201                                call, call->event_ctx,
 202                                dce_conn->auth_state.auth_info->credentials,
 203                                &dce_conn->auth_state.auth_info->credentials);
 204         if (NT_STATUS_IS_OK(status)) {
 205                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 206                                              dce_conn,
 207                                              &dce_conn->auth_state.session_info);
 208                 if (!NT_STATUS_IS_OK(status)) {
 209                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 210                         return false;
 211                 }
 212                 /* Now that we are authenticated, go back to the generic session key... */
 213                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 214                 return true;
 215         } else {
 216                 DEBUG(4, ("GENSEC mech rejected the incoming authentication at bind_auth3: %s\n",
 217                           nt_errstr(status)));
 218                 return false;
 219         }
 220 }
 221
 222 /*
 223   parse any auth information from a dcerpc alter request
 224   return false if we can't handle the auth request for some
 225   reason (in which case we send a bind_nak (is this true for here?))
 226 */
 227 bool dcesrv_auth_alter(struct dcesrv_call_state *call)
 228 {
 229         struct ncacn_packet *pkt = &call->pkt;
 230         struct dcesrv_connection *dce_conn = call->conn;
 231         NTSTATUS status;
 232         uint32_t auth_length;
 233
 234         /* on a pure interface change there is no auth blob */
 235         if (pkt->u.alter.auth_info.length == 0) {
 236                 return true;
 237         }
 238
 239         /* We can't work without an existing gensec state */
 240         if (!dce_conn->auth_state.gensec_security) {
 241                 return false;
 242         }
 243
 244         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 245         if (!dce_conn->auth_state.auth_info) {
 246                 return false;
 247         }
 248
 249         status = dcerpc_pull_auth_trailer(pkt, call, &pkt->u.alter.auth_info,
 250                                           dce_conn->auth_state.auth_info,
 251                                           &auth_length, true);
 252         if (!NT_STATUS_IS_OK(status)) {
 253                 return false;
 254         }
 255
 256         return true;
 257 }
 258
 259 /*
 260   add any auth information needed in a alter ack, and process the authentication
 261   information found in the alter.
 262 */
 263 NTSTATUS dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 264 {
 265         struct dcesrv_connection *dce_conn = call->conn;
 266         NTSTATUS status;
 267
 268         /* on a pure interface change there is no auth_info structure
 269            setup */
 270         if (!call->conn->auth_state.auth_info ||
 271             dce_conn->auth_state.auth_info->credentials.length == 0) {
 272                 return NT_STATUS_OK;
 273         }
 274
 275         if (!call->conn->auth_state.gensec_security) {
 276                 return NT_STATUS_INVALID_PARAMETER;
 277         }
 278
 279         status = gensec_update(dce_conn->auth_state.gensec_security,
 280                                call, call->event_ctx,
 281                                dce_conn->auth_state.auth_info->credentials,
 282                                &dce_conn->auth_state.auth_info->credentials);
 283
 284         if (NT_STATUS_IS_OK(status)) {
 285                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 286                                              dce_conn,
 287                                              &dce_conn->auth_state.session_info);
 288                 if (!NT_STATUS_IS_OK(status)) {
 289                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 290                         return status;
 291                 }
 292
 293                 /* Now that we are authenticated, got back to the generic session key... */
 294                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 295                 return NT_STATUS_OK;
 296         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 297                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 298                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 299                 return NT_STATUS_OK;
 300         }
 301
 302         DEBUG(4, ("GENSEC mech rejected the incoming authentication at auth alter_ack: %s\n",
 303                   nt_errstr(status)));
 304         return status;
 305 }
 306
 307 /*
 308   check credentials on a request
 309 */
 310 bool dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 311 {
 312         struct ncacn_packet *pkt = &call->pkt;
 313         struct dcesrv_connection *dce_conn = call->conn;
 314         struct dcerpc_auth auth;
 315         NTSTATUS status;
 316         uint32_t auth_length;
 317         size_t hdr_size = DCERPC_REQUEST_LENGTH;
 318
 319         if (!dce_conn->auth_state.auth_info ||
 320             !dce_conn->auth_state.gensec_security) {
 321                 return true;
 322         }
 323
 324         if (pkt->pfc_flags & DCERPC_PFC_FLAG_OBJECT_UUID) {
 325                 hdr_size += 16;
 326         }
 327
 328         switch (dce_conn->auth_state.auth_info->auth_level) {
 329         case DCERPC_AUTH_LEVEL_PRIVACY:
 330         case DCERPC_AUTH_LEVEL_INTEGRITY:
 331                 break;
 332
 333         case DCERPC_AUTH_LEVEL_CONNECT:
 334                 if (pkt->auth_length != 0) {
 335                         break;
 336                 }
 337                 return true;
 338         case DCERPC_AUTH_LEVEL_NONE:
 339                 if (pkt->auth_length != 0) {
 340                         return false;
 341                 }
 342                 return true;
 343
 344         default:
 345                 return false;
 346         }
 347
 348         status = dcerpc_pull_auth_trailer(pkt, call,
 349                                           &pkt->u.request.stub_and_verifier,
 350                                           &auth, &auth_length, false);
 351         if (!NT_STATUS_IS_OK(status)) {
 352                 return false;
 353         }
 354
 355         pkt->u.request.stub_and_verifier.length -= auth_length;
 356
 357         /* check signature or unseal the packet */
 358         switch (dce_conn->auth_state.auth_info->auth_level) {
 359         case DCERPC_AUTH_LEVEL_PRIVACY:
 360                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 361                                               full_packet->data + hdr_size,
 362                                               pkt->u.request.stub_and_verifier.length,
 363                                               full_packet->data,
 364                                               full_packet->length-auth.credentials.length,
 365                                               &auth.credentials);
 366                 memcpy(pkt->u.request.stub_and_verifier.data,
 367                        full_packet->data + hdr_size,
 368                        pkt->u.request.stub_and_verifier.length);
 369                 break;
 370
 371         case DCERPC_AUTH_LEVEL_INTEGRITY:
 372                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 373                                              pkt->u.request.stub_and_verifier.data,
 374                                              pkt->u.request.stub_and_verifier.length,
 375                                              full_packet->data,
 376                                              full_packet->length-auth.credentials.length,
 377                                              &auth.credentials);
 378                 break;
 379
 380         case DCERPC_AUTH_LEVEL_CONNECT:
 381                 /* for now we ignore possible signatures here */
 382                 status = NT_STATUS_OK;
 383                 break;
 384
 385         default:
 386                 status = NT_STATUS_INVALID_LEVEL;
 387                 break;
 388         }
 389
 390         /* remove the indicated amount of padding */
 391         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 392                 return false;
 393         }
 394         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 395
 396         return NT_STATUS_IS_OK(status);
 397 }
 398
 399
 400 /*
 401    push a signed or sealed dcerpc request packet into a blob
 402 */
 403 bool dcesrv_auth_response(struct dcesrv_call_state *call,
 404                           DATA_BLOB *blob, size_t sig_size,
 405                           struct ncacn_packet *pkt)
 406 {
 407         struct dcesrv_connection *dce_conn = call->conn;
 408         NTSTATUS status;
 409         enum ndr_err_code ndr_err;
 410         struct ndr_push *ndr;
 411         uint32_t payload_length;
 412         DATA_BLOB creds2;
 413
 414         /* non-signed packets are simple */
 415         if (sig_size == 0) {
 416                 status = ncacn_push_auth(blob, call, pkt, NULL);
 417                 return NT_STATUS_IS_OK(status);
 418         }
 419
 420         switch (dce_conn->auth_state.auth_info->auth_level) {
 421         case DCERPC_AUTH_LEVEL_PRIVACY:
 422         case DCERPC_AUTH_LEVEL_INTEGRITY:
 423                 break;
 424
 425         case DCERPC_AUTH_LEVEL_CONNECT:
 426                 /*
 427                  * TODO: let the gensec mech decide if it wants to generate a
 428                  *       signature that might be needed for schannel...
 429                  */
 430                 status = ncacn_push_auth(blob, call, pkt, NULL);
 431                 return NT_STATUS_IS_OK(status);
 432
 433         case DCERPC_AUTH_LEVEL_NONE:
 434                 status = ncacn_push_auth(blob, call, pkt, NULL);
 435                 return NT_STATUS_IS_OK(status);
 436
 437         default:
 438                 return false;
 439         }
 440
 441         ndr = ndr_push_init_ctx(call);
 442         if (!ndr) {
 443                 return false;
 444         }
 445
 446         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 447                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 448         }
 449
 450         ndr_err = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 451         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 452                 return false;
 453         }
 454
 455         /* pad to 16 byte multiple in the payload portion of the
 456            packet. This matches what w2k3 does. Note that we can't use
 457            ndr_push_align() as that is relative to the start of the
 458            whole packet, whereas w2k8 wants it relative to the start
 459            of the stub */
 460         dce_conn->auth_state.auth_info->auth_pad_length =
 461                 (16 - (pkt->u.response.stub_and_verifier.length & 15)) & 15;
 462         ndr_err = ndr_push_zero(ndr,
 463                                 dce_conn->auth_state.auth_info->auth_pad_length);
 464         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 465                 return false;
 466         }
 467
 468         payload_length = pkt->u.response.stub_and_verifier.length +
 469                 dce_conn->auth_state.auth_info->auth_pad_length;
 470
 471         /* we start without signature, it will appended later */
 472         dce_conn->auth_state.auth_info->credentials = data_blob(NULL, 0);
 473
 474         /* add the auth verifier */
 475         ndr_err = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS,
 476                                        dce_conn->auth_state.auth_info);
 477         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 478                 return false;
 479         }
 480
 481         /* extract the whole packet as a blob */
 482         *blob = ndr_push_blob(ndr);
 483
 484         /*
 485          * Setup the frag and auth length in the packet buffer.
 486          * This is needed if the GENSEC mech does AEAD signing
 487          * of the packet headers. The signature itself will be
 488          * appended later.
 489          */
 490         dcerpc_set_frag_length(blob, blob->length + sig_size);
 491         dcerpc_set_auth_length(blob, sig_size);
 492
 493         /* sign or seal the packet */
 494         switch (dce_conn->auth_state.auth_info->auth_level) {
 495         case DCERPC_AUTH_LEVEL_PRIVACY:
 496                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 497                                             call,
 498                                             ndr->data + DCERPC_REQUEST_LENGTH,
 499                                             payload_length,
 500                                             blob->data,
 501                                             blob->length,
 502                                             &creds2);
 503                 break;
 504
 505         case DCERPC_AUTH_LEVEL_INTEGRITY:
 506                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 507                                             call,
 508                                             ndr->data + DCERPC_REQUEST_LENGTH,
 509                                             payload_length,
 510                                             blob->data,
 511                                             blob->length,
 512                                             &creds2);
 513                 break;
 514
 515         default:
 516                 status = NT_STATUS_INVALID_LEVEL;
 517                 break;
 518         }
 519
 520         if (!NT_STATUS_IS_OK(status)) {
 521                 return false;
 522         }
 523
 524         if (creds2.length != sig_size) {
 525                 DEBUG(3,("dcesrv_auth_response: creds2.length[%u] != sig_size[%u] pad[%u] stub[%u]\n",
 526                          (unsigned)creds2.length, (uint32_t)sig_size,
 527                          (unsigned)dce_conn->auth_state.auth_info->auth_pad_length,
 528                          (unsigned)pkt->u.response.stub_and_verifier.length));
 529                 dcerpc_set_frag_length(blob, blob->length + creds2.length);
 530                 dcerpc_set_auth_length(blob, creds2.length);
 531         }
 532
 533         if (!data_blob_append(call, blob, creds2.data, creds2.length)) {
 534                 status = NT_STATUS_NO_MEMORY;
 535                 return false;
 536         }
 537         data_blob_free(&creds2);
 538
 539         return true;
 540 }