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