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 2 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, write to the Free Software
  21    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  22 */
  23
  24 #include "includes.h"
  25 #include "rpc_server/dcerpc_server.h"
  26 #include "librpc/gen_ndr/ndr_dcerpc.h"
  27 #include "auth/gensec/gensec.h"
  28
  29 /*
  30   parse any auth information from a dcerpc bind request
  31   return False if we can't handle the auth request for some
  32   reason (in which case we send a bind_nak)
  33 */
  34 BOOL dcesrv_auth_bind(struct dcesrv_call_state *call)
  35 {
  36         struct cli_credentials *server_credentials;
  37         struct ncacn_packet *pkt = &call->pkt;
  38         struct dcesrv_connection *dce_conn = call->conn;
  39         struct dcesrv_auth *auth = &dce_conn->auth_state;
  40         NTSTATUS status;
  41
  42         if (pkt->u.bind.auth_info.length == 0) {
  43                 dce_conn->auth_state.auth_info = NULL;
  44                 return True;
  45         }
  46
  47         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  48         if (!dce_conn->auth_state.auth_info) {
  49                 return False;
  50         }
  51
  52         status = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
  53                                       call,
  54                                       dce_conn->auth_state.auth_info,
  55                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
  56         if (!NT_STATUS_IS_OK(status)) {
  57                 return False;
  58         }
  59
  60         status = gensec_server_start(dce_conn, &auth->gensec_security, call->event_ctx);
  61         if (!NT_STATUS_IS_OK(status)) {
  62                 DEBUG(1, ("Failed to start GENSEC for DCERPC server: %s\n", nt_errstr(status)));
  63                 return False;
  64         }
  65
  66         server_credentials
  67                 = cli_credentials_init(call);
  68         if (!server_credentials) {
  69                 DEBUG(1, ("Failed to init server credentials\n"));
  70                 return False;
  71         }
  72
  73         cli_credentials_set_conf(server_credentials);
  74         status = cli_credentials_set_machine_account(server_credentials);
  75         if (!NT_STATUS_IS_OK(status)) {
  76                 DEBUG(10, ("Failed to obtain server credentials, perhaps a standalone server?: %s\n", nt_errstr(status)));
  77                 talloc_free(server_credentials);
  78                 server_credentials = NULL;
  79         }
  80
  81         gensec_set_credentials(auth->gensec_security, server_credentials);
  82
  83         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  84                                                auth->auth_info->auth_level);
  85
  86         if (!NT_STATUS_IS_OK(status)) {
  87                 DEBUG(1, ("Failed to start GENSEC mechanism for DCERPC server: auth_type=%d, auth_level=%d: %s\n",
  88                           (int)auth->auth_info->auth_type,
  89                           (int)auth->auth_info->auth_level,
  90                           nt_errstr(status)));
  91                 return False;
  92         }
  93
  94         return True;
  95 }
  96
  97 /*
  98   add any auth information needed in a bind ack, and process the authentication
  99   information found in the bind.
 100 */
 101 BOOL dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 102 {
 103         struct dcesrv_connection *dce_conn = call->conn;
 104         NTSTATUS status;
 105
 106         if (!call->conn->auth_state.gensec_security) {
 107                 return True;
 108         }
 109
 110         status = gensec_update(dce_conn->auth_state.gensec_security,
 111                                call,
 112                                dce_conn->auth_state.auth_info->credentials,
 113                                &dce_conn->auth_state.auth_info->credentials);
 114
 115         if (NT_STATUS_IS_OK(status)) {
 116                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 117                                              &dce_conn->auth_state.session_info);
 118                 if (!NT_STATUS_IS_OK(status)) {
 119                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 120                         return False;
 121                 }
 122
 123                 /* Now that we are authenticated, go back to the generic session key... */
 124                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 125                 return True;
 126         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 127                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 128                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 129                 return True;
 130         } else {
 131                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 132                 return False;
 133         }
 134 }
 135
 136
 137 /*
 138   process the final stage of a auth request
 139 */
 140 BOOL dcesrv_auth_auth3(struct dcesrv_call_state *call)
 141 {
 142         struct ncacn_packet *pkt = &call->pkt;
 143         struct dcesrv_connection *dce_conn = call->conn;
 144         NTSTATUS status;
 145
 146         /* We can't work without an existing gensec state, and an new blob to feed it */
 147         if (!dce_conn->auth_state.auth_info ||
 148             !dce_conn->auth_state.gensec_security ||
 149             pkt->u.auth3.auth_info.length == 0) {
 150                 return False;
 151         }
 152
 153         status = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 154                                       call,
 155                                       dce_conn->auth_state.auth_info,
 156                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 157         if (!NT_STATUS_IS_OK(status)) {
 158                 return False;
 159         }
 160
 161         /* Pass the extra data we got from the client down to gensec for processing */
 162         status = gensec_update(dce_conn->auth_state.gensec_security,
 163                                call,
 164                                dce_conn->auth_state.auth_info->credentials,
 165                                &dce_conn->auth_state.auth_info->credentials);
 166         if (NT_STATUS_IS_OK(status)) {
 167                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 168                                              &dce_conn->auth_state.session_info);
 169                 if (!NT_STATUS_IS_OK(status)) {
 170                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 171                         return False;
 172                 }
 173                 /* Now that we are authenticated, go back to the generic session key... */
 174                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 175                 return True;
 176         } else {
 177                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 178                           nt_errstr(status)));
 179                 return False;
 180         }
 181
 182         return True;
 183 }
 184
 185 /*
 186   parse any auth information from a dcerpc alter request
 187   return False if we can't handle the auth request for some
 188   reason (in which case we send a bind_nak (is this true for here?))
 189 */
 190 BOOL dcesrv_auth_alter(struct dcesrv_call_state *call)
 191 {
 192         struct ncacn_packet *pkt = &call->pkt;
 193         struct dcesrv_connection *dce_conn = call->conn;
 194         NTSTATUS status;
 195
 196         /* on a pure interface change there is no auth blob */
 197         if (pkt->u.alter.auth_info.length == 0) {
 198                 return True;
 199         }
 200
 201         /* We can't work without an existing gensec state */
 202         if (!dce_conn->auth_state.gensec_security) {
 203                 return False;
 204         }
 205
 206         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
 207         if (!dce_conn->auth_state.auth_info) {
 208                 return False;
 209         }
 210
 211         status = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 212                                       call,
 213                                       dce_conn->auth_state.auth_info,
 214                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 215         if (!NT_STATUS_IS_OK(status)) {
 216                 return False;
 217         }
 218
 219         return True;
 220 }
 221
 222 /*
 223   add any auth information needed in a alter ack, and process the authentication
 224   information found in the alter.
 225 */
 226 BOOL dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct ncacn_packet *pkt)
 227 {
 228         struct dcesrv_connection *dce_conn = call->conn;
 229         NTSTATUS status;
 230
 231         /* on a pure interface change there is no auth_info structure
 232            setup */
 233         if (!call->conn->auth_state.auth_info) {
 234                 return True;
 235         }
 236
 237         if (!call->conn->auth_state.gensec_security) {
 238                 return False;
 239         }
 240
 241         status = gensec_update(dce_conn->auth_state.gensec_security,
 242                                call,
 243                                dce_conn->auth_state.auth_info->credentials,
 244                                &dce_conn->auth_state.auth_info->credentials);
 245
 246         if (NT_STATUS_IS_OK(status)) {
 247                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 248                                              &dce_conn->auth_state.session_info);
 249                 if (!NT_STATUS_IS_OK(status)) {
 250                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 251                         return False;
 252                 }
 253
 254                 /* Now that we are authenticated, got back to the generic session key... */
 255                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 256                 return True;
 257         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 258                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 259                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 260                 return True;
 261         } else {
 262                 DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 263                 return True;
 264         }
 265 }
 266
 267 /*
 268   generate a CONNECT level verifier
 269 */
 270 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 271 {
 272         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 273         if (blob->data == NULL) {
 274                 return NT_STATUS_NO_MEMORY;
 275         }
 276         SIVAL(blob->data, 0, 1);
 277         memset(blob->data+4, 0, 12);
 278         return NT_STATUS_OK;
 279 }
 280
 281 /*
 282   generate a CONNECT level verifier
 283 */
 284 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 285 {
 286         if (blob->length != 16 ||
 287             IVAL(blob->data, 0) != 1) {
 288                 return NT_STATUS_ACCESS_DENIED;
 289         }
 290         return NT_STATUS_OK;
 291 }
 292
 293
 294 /*
 295   check credentials on a request
 296 */
 297 BOOL dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 298 {
 299         struct ncacn_packet *pkt = &call->pkt;
 300         struct dcesrv_connection *dce_conn = call->conn;
 301         DATA_BLOB auth_blob;
 302         struct dcerpc_auth auth;
 303         struct ndr_pull *ndr;
 304         NTSTATUS status;
 305
 306         if (!dce_conn->auth_state.auth_info ||
 307             !dce_conn->auth_state.gensec_security) {
 308                 return True;
 309         }
 310
 311         auth_blob.length = 8 + pkt->auth_length;
 312
 313         /* check for a valid length */
 314         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 315                 return False;
 316         }
 317
 318         auth_blob.data =
 319                 pkt->u.request.stub_and_verifier.data +
 320                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 321         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 322
 323         /* pull the auth structure */
 324         ndr = ndr_pull_init_blob(&auth_blob, call);
 325         if (!ndr) {
 326                 return False;
 327         }
 328
 329         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 330                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 331         }
 332
 333         status = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 334         if (!NT_STATUS_IS_OK(status)) {
 335                 talloc_free(ndr);
 336                 return False;
 337         }
 338
 339         /* check signature or unseal the packet */
 340         switch (dce_conn->auth_state.auth_info->auth_level) {
 341         case DCERPC_AUTH_LEVEL_PRIVACY:
 342                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 343                                               call,
 344                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 345                                               pkt->u.request.stub_and_verifier.length,
 346                                               full_packet->data,
 347                                               full_packet->length-auth.credentials.length,
 348                                               &auth.credentials);
 349                 memcpy(pkt->u.request.stub_and_verifier.data,
 350                        full_packet->data + DCERPC_REQUEST_LENGTH,
 351                        pkt->u.request.stub_and_verifier.length);
 352                 break;
 353
 354         case DCERPC_AUTH_LEVEL_INTEGRITY:
 355                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 356                                              call,
 357                                              pkt->u.request.stub_and_verifier.data,
 358                                              pkt->u.request.stub_and_verifier.length,
 359                                              full_packet->data,
 360                                              full_packet->length-auth.credentials.length,
 361                                              &auth.credentials);
 362                 break;
 363
 364         case DCERPC_AUTH_LEVEL_CONNECT:
 365                 status = dcesrv_check_connect_verifier(&auth.credentials);
 366                 break;
 367
 368         default:
 369                 status = NT_STATUS_INVALID_LEVEL;
 370                 break;
 371         }
 372
 373         /* remove the indicated amount of padding */
 374         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 375                 talloc_free(ndr);
 376                 return False;
 377         }
 378         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 379         talloc_free(ndr);
 380
 381         return NT_STATUS_IS_OK(status);
 382 }
 383
 384
 385 /*
 386    push a signed or sealed dcerpc request packet into a blob
 387 */
 388 BOOL dcesrv_auth_response(struct dcesrv_call_state *call,
 389                           DATA_BLOB *blob, struct ncacn_packet *pkt)
 390 {
 391         struct dcesrv_connection *dce_conn = call->conn;
 392         NTSTATUS status;
 393         struct ndr_push *ndr;
 394         uint32_t payload_length;
 395
 396         /* non-signed packets are simple */
 397         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 398                 status = ncacn_push_auth(blob, call, pkt, NULL);
 399                 return NT_STATUS_IS_OK(status);
 400         }
 401
 402         ndr = ndr_push_init_ctx(call);
 403         if (!ndr) {
 404                 return False;
 405         }
 406
 407         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 408                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 409         }
 410
 411         status = ndr_push_ncacn_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 412         if (!NT_STATUS_IS_OK(status)) {
 413                 return False;
 414         }
 415
 416         /* pad to 16 byte multiple, match win2k3 */
 417         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 16);
 418         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 419
 420         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 421
 422         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 423                 status = dcesrv_connect_verifier(call,
 424                                                  &dce_conn->auth_state.auth_info->credentials);
 425                 if (!NT_STATUS_IS_OK(status)) {
 426                         return False;
 427                 }
 428         } else {
 429                 dce_conn->auth_state.auth_info->credentials
 430                         = data_blob_talloc(call, NULL,
 431                                            gensec_sig_size(dce_conn->auth_state.gensec_security,
 432                                                            payload_length));
 433         }
 434
 435         /* add the auth verifier */
 436         status = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, dce_conn->auth_state.auth_info);
 437         if (!NT_STATUS_IS_OK(status)) {
 438                 return False;
 439         }
 440
 441         /* extract the whole packet as a blob */
 442         *blob = ndr_push_blob(ndr);
 443
 444         /* fill in the fragment length and auth_length, we can't fill
 445            in these earlier as we don't know the signature length (it
 446            could be variable length) */
 447         dcerpc_set_frag_length(blob, blob->length);
 448         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 449
 450         /* sign or seal the packet */
 451         switch (dce_conn->auth_state.auth_info->auth_level) {
 452         case DCERPC_AUTH_LEVEL_PRIVACY:
 453                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 454                                             call,
 455                                             ndr->data + DCERPC_REQUEST_LENGTH,
 456                                             payload_length,
 457                                             blob->data,
 458                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 459                                             &dce_conn->auth_state.auth_info->credentials);
 460                 break;
 461
 462         case DCERPC_AUTH_LEVEL_INTEGRITY:
 463                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 464                                             call,
 465                                             ndr->data + DCERPC_REQUEST_LENGTH,
 466                                             payload_length,
 467                                             blob->data,
 468                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 469                                             &dce_conn->auth_state.auth_info->credentials);
 470
 471                 break;
 472
 473         case DCERPC_AUTH_LEVEL_CONNECT:
 474                 break;
 475
 476         default:
 477                 status = NT_STATUS_INVALID_LEVEL;
 478                 break;
 479         }
 480
 481         if (!NT_STATUS_IS_OK(status)) {
 482                 return False;
 483         }
 484
 485         memcpy(blob->data + blob->length - dce_conn->auth_state.auth_info->credentials.length,
 486                dce_conn->auth_state.auth_info->credentials.data, dce_conn->auth_state.auth_info->credentials.length);
 487
 488         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 489
 490         return True;
 491 }