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
  27 /*
  28   startup the cryptographic side of an authenticated dcerpc server
  29 */
  30 NTSTATUS dcesrv_crypto_select_type(struct dcesrv_connection *dce_conn,
  31                                struct dcesrv_auth *auth)
  32 {
  33         NTSTATUS status;
  34         if (auth->auth_info->auth_level != DCERPC_AUTH_LEVEL_INTEGRITY &&
  35             auth->auth_info->auth_level != DCERPC_AUTH_LEVEL_PRIVACY &&
  36             auth->auth_info->auth_level != DCERPC_AUTH_LEVEL_CONNECT) {
  37                 DEBUG(2,("auth_level %d not supported in dcesrv auth\n",
  38                          auth->auth_info->auth_level));
  39                 return NT_STATUS_INVALID_PARAMETER;
  40         }
  41
  42         if (auth->gensec_security != NULL) {
  43                 /* TODO:
  44                  * this this function should not be called
  45                  * twice per dcesrv_connection!
  46                  *
  47                  * so we need to find out the right
  48                  * dcerpc error to return
  49                  */
  50         }
  51
  52         status = gensec_server_start(dce_conn, &auth->gensec_security);
  53         if (!NT_STATUS_IS_OK(status)) {
  54                 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
  55                 return status;
  56         }
  57
  58         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  59                                                auth->auth_info->auth_level);
  60
  61         if (!NT_STATUS_IS_OK(status)) {
  62                 DEBUG(1, ("Failed to start GENSEC mech-specific server code (%d): %s\n",
  63                           (int)auth->auth_info->auth_type,
  64                           nt_errstr(status)));
  65                 return status;
  66         }
  67
  68         return status;
  69 }
  70
  71 /*
  72   parse any auth information from a dcerpc bind request
  73   return False if we can't handle the auth request for some
  74   reason (in which case we send a bind_nak)
  75 */
  76 BOOL dcesrv_auth_bind(struct dcesrv_call_state *call)
  77 {
  78         struct dcerpc_packet *pkt = &call->pkt;
  79         struct dcesrv_connection *dce_conn = call->conn;
  80         NTSTATUS status;
  81
  82         if (pkt->u.bind.auth_info.length == 0) {
  83                 dce_conn->auth_state.auth_info = NULL;
  84                 return True;
  85         }
  86
  87         dce_conn->auth_state.auth_info = talloc(dce_conn, struct dcerpc_auth);
  88         if (!dce_conn->auth_state.auth_info) {
  89                 return False;
  90         }
  91
  92         status = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
  93                                       call,
  94                                       dce_conn->auth_state.auth_info,
  95                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
  96         if (!NT_STATUS_IS_OK(status)) {
  97                 return False;
  98         }
  99
 100         status = dcesrv_crypto_select_type(dce_conn, &dce_conn->auth_state);
 101         if (!NT_STATUS_IS_OK(status)) {
 102                 return False;
 103         }
 104
 105         return True;
 106 }
 107
 108 /*
 109   add any auth information needed in a bind ack, and process the authentication
 110   information found in the bind.
 111 */
 112 BOOL dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct dcerpc_packet *pkt)
 113 {
 114         struct dcesrv_connection *dce_conn = call->conn;
 115         NTSTATUS status;
 116
 117         if (!call->conn->auth_state.gensec_security) {
 118                 return True;
 119         }
 120
 121         status = gensec_update(dce_conn->auth_state.gensec_security,
 122                                call,
 123                                dce_conn->auth_state.auth_info->credentials,
 124                                &dce_conn->auth_state.auth_info->credentials);
 125
 126         if (NT_STATUS_IS_OK(status)) {
 127                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 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 False;
 132                 }
 133
 134                 /* Now that we are authenticated, got back to the generic session key... */
 135                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 136                 return True;
 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 True;
 141         } else {
 142                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 143                 return False;
 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 dcerpc_packet *pkt = &call->pkt;
 154         struct dcesrv_connection *dce_conn = call->conn;
 155         NTSTATUS status;
 156
 157         /* We can't work without an existing gensec state, and an new blob to feed it */
 158         if (!dce_conn->auth_state.auth_info ||
 159             !dce_conn->auth_state.gensec_security ||
 160             pkt->u.auth3.auth_info.length == 0) {
 161                 return False;
 162         }
 163
 164         status = ndr_pull_struct_blob(&pkt->u.auth3.auth_info,
 165                                       call,
 166                                       dce_conn->auth_state.auth_info,
 167                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 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->auth_state.session_info);
 180                 if (!NT_STATUS_IS_OK(status)) {
 181                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 182                         return False;
 183                 }
 184                 /* Now that we are authenticated, got back to the generic session key... */
 185                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 186                 return True;
 187         } else {
 188                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 189                           nt_errstr(status)));
 190                 return False;
 191         }
 192
 193         return True;
 194 }
 195
 196 /*
 197   parse any auth information from a dcerpc alter request
 198   return False if we can't handle the auth request for some
 199   reason (in which case we send a bind_nak (is this true for here?))
 200 */
 201 BOOL dcesrv_auth_alter(struct dcesrv_call_state *call)
 202 {
 203         struct dcerpc_packet *pkt = &call->pkt;
 204         struct dcesrv_connection *dce_conn = call->conn;
 205         NTSTATUS status;
 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 = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 223                                       call,
 224                                       dce_conn->auth_state.auth_info,
 225                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 226         if (!NT_STATUS_IS_OK(status)) {
 227                 return False;
 228         }
 229
 230         return True;
 231 }
 232
 233 /*
 234   add any auth information needed in a alter ack, and process the authentication
 235   information found in the alter.
 236 */
 237 BOOL dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct dcerpc_packet *pkt)
 238 {
 239         struct dcesrv_connection *dce_conn = call->conn;
 240         NTSTATUS status;
 241
 242         /* on a pure interface change there is no auth_info structure
 243            setup */
 244         if (!call->conn->auth_state.auth_info) {
 245                 return True;
 246         }
 247
 248         if (!call->conn->auth_state.gensec_security) {
 249                 return False;
 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 False;
 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 True;
 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 True;
 272         } else {
 273                 DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 274                 return True;
 275         }
 276 }
 277
 278 /*
 279   generate a CONNECT level verifier
 280 */
 281 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 282 {
 283         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 284         if (blob->data == NULL) {
 285                 return NT_STATUS_NO_MEMORY;
 286         }
 287         SIVAL(blob->data, 0, 1);
 288         memset(blob->data+4, 0, 12);
 289         return NT_STATUS_OK;
 290 }
 291
 292 /*
 293   generate a CONNECT level verifier
 294 */
 295 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 296 {
 297         if (blob->length != 16 ||
 298             IVAL(blob->data, 0) != 1) {
 299                 return NT_STATUS_ACCESS_DENIED;
 300         }
 301         return NT_STATUS_OK;
 302 }
 303
 304
 305 /*
 306   check credentials on a request
 307 */
 308 BOOL dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 309 {
 310         struct dcerpc_packet *pkt = &call->pkt;
 311         struct dcesrv_connection *dce_conn = call->conn;
 312         DATA_BLOB auth_blob;
 313         struct dcerpc_auth auth;
 314         struct ndr_pull *ndr;
 315         NTSTATUS status;
 316
 317         if (!dce_conn->auth_state.auth_info ||
 318             !dce_conn->auth_state.gensec_security) {
 319                 return True;
 320         }
 321
 322         auth_blob.length = 8 + pkt->auth_length;
 323
 324         /* check for a valid length */
 325         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 326                 return False;
 327         }
 328
 329         auth_blob.data =
 330                 pkt->u.request.stub_and_verifier.data +
 331                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 332         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 333
 334         /* pull the auth structure */
 335         ndr = ndr_pull_init_blob(&auth_blob, call);
 336         if (!ndr) {
 337                 return False;
 338         }
 339
 340         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 341                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 342         }
 343
 344         status = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 345         if (!NT_STATUS_IS_OK(status)) {
 346                 talloc_free(ndr);
 347                 return False;
 348         }
 349
 350         /* check signature or unseal the packet */
 351         switch (dce_conn->auth_state.auth_info->auth_level) {
 352         case DCERPC_AUTH_LEVEL_PRIVACY:
 353                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 354                                               call,
 355                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 356                                               pkt->u.request.stub_and_verifier.length,
 357                                               full_packet->data,
 358                                               full_packet->length-auth.credentials.length,
 359                                               &auth.credentials);
 360                 memcpy(pkt->u.request.stub_and_verifier.data,
 361                        full_packet->data + DCERPC_REQUEST_LENGTH,
 362                        pkt->u.request.stub_and_verifier.length);
 363                 break;
 364
 365         case DCERPC_AUTH_LEVEL_INTEGRITY:
 366                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 367                                              call,
 368                                              pkt->u.request.stub_and_verifier.data,
 369                                              pkt->u.request.stub_and_verifier.length,
 370                                              full_packet->data,
 371                                              full_packet->length-auth.credentials.length,
 372                                              &auth.credentials);
 373                 break;
 374
 375         case DCERPC_AUTH_LEVEL_CONNECT:
 376                 status = dcesrv_check_connect_verifier(&auth.credentials);
 377                 break;
 378
 379         default:
 380                 status = NT_STATUS_INVALID_LEVEL;
 381                 break;
 382         }
 383
 384         /* remove the indicated amount of padding */
 385         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 386                 talloc_free(ndr);
 387                 return False;
 388         }
 389         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 390         talloc_free(ndr);
 391
 392         return NT_STATUS_IS_OK(status);
 393 }
 394
 395
 396 /*
 397    push a signed or sealed dcerpc request packet into a blob
 398 */
 399 BOOL dcesrv_auth_response(struct dcesrv_call_state *call,
 400                           DATA_BLOB *blob, struct dcerpc_packet *pkt)
 401 {
 402         struct dcesrv_connection *dce_conn = call->conn;
 403         NTSTATUS status;
 404         struct ndr_push *ndr;
 405         uint32_t payload_length;
 406
 407         /* non-signed packets are simple */
 408         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 409                 status = dcerpc_push_auth(blob, call, pkt, NULL);
 410                 return NT_STATUS_IS_OK(status);
 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         status = ndr_push_dcerpc_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 423         if (!NT_STATUS_IS_OK(status)) {
 424                 return False;
 425         }
 426
 427         /* pad to 8 byte multiple */
 428         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 8);
 429         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 430
 431         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 432
 433         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 434                 status = dcesrv_connect_verifier(call,
 435                                                  &dce_conn->auth_state.auth_info->credentials);
 436                 if (!NT_STATUS_IS_OK(status)) {
 437                         return False;
 438                 }
 439         } else {
 440                 dce_conn->auth_state.auth_info->credentials
 441                         = data_blob_talloc(call, NULL,
 442                                            gensec_sig_size(dce_conn->auth_state.gensec_security));
 443         }
 444
 445         /* add the auth verifier */
 446         status = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, dce_conn->auth_state.auth_info);
 447         if (!NT_STATUS_IS_OK(status)) {
 448                 return False;
 449         }
 450
 451         /* extract the whole packet as a blob */
 452         *blob = ndr_push_blob(ndr);
 453
 454         /* fill in the fragment length and auth_length, we can't fill
 455            in these earlier as we don't know the signature length (it
 456            could be variable length) */
 457         dcerpc_set_frag_length(blob, blob->length);
 458         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 459
 460         /* sign or seal the packet */
 461         switch (dce_conn->auth_state.auth_info->auth_level) {
 462         case DCERPC_AUTH_LEVEL_PRIVACY:
 463                 status = gensec_seal_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                 break;
 471
 472         case DCERPC_AUTH_LEVEL_INTEGRITY:
 473                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 474                                             call,
 475                                             ndr->data + DCERPC_REQUEST_LENGTH,
 476                                             payload_length,
 477                                             blob->data,
 478                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 479                                             &dce_conn->auth_state.auth_info->credentials);
 480
 481                 break;
 482
 483         case DCERPC_AUTH_LEVEL_CONNECT:
 484                 break;
 485
 486         default:
 487                 status = NT_STATUS_INVALID_LEVEL;
 488                 break;
 489         }
 490
 491         if (!NT_STATUS_IS_OK(status)) {
 492                 return False;
 493         }
 494
 495         memcpy(blob->data + blob->length - dce_conn->auth_state.auth_info->credentials.length,
 496                dce_conn->auth_state.auth_info->credentials.data, dce_conn->auth_state.auth_info->credentials.length);
 497
 498         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 499
 500         return True;
 501 }