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_p(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         /* We can't work without an existing gensec state, and an new blob to feed it */
 208         if (!dce_conn->auth_state.gensec_security ||
 209             pkt->u.alter.auth_info.length == 0) {
 210                 return False;
 211         }
 212
 213         dce_conn->auth_state.auth_info = talloc_p(dce_conn, struct dcerpc_auth);
 214         if (!dce_conn->auth_state.auth_info) {
 215                 return False;
 216         }
 217
 218         status = ndr_pull_struct_blob(&pkt->u.alter.auth_info,
 219                                       call,
 220                                       dce_conn->auth_state.auth_info,
 221                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 222         if (!NT_STATUS_IS_OK(status)) {
 223                 return False;
 224         }
 225
 226         return True;
 227 }
 228
 229 /*
 230   add any auth information needed in a alter ack, and process the authentication
 231   information found in the alter.
 232 */
 233 BOOL dcesrv_auth_alter_ack(struct dcesrv_call_state *call, struct dcerpc_packet *pkt)
 234 {
 235         struct dcesrv_connection *dce_conn = call->conn;
 236         NTSTATUS status;
 237
 238         if (!call->conn->auth_state.gensec_security) {
 239                 return False;
 240         }
 241
 242         status = gensec_update(dce_conn->auth_state.gensec_security,
 243                                call,
 244                                dce_conn->auth_state.auth_info->credentials,
 245                                &dce_conn->auth_state.auth_info->credentials);
 246
 247         if (NT_STATUS_IS_OK(status)) {
 248                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 249                                              &dce_conn->auth_state.session_info);
 250                 if (!NT_STATUS_IS_OK(status)) {
 251                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 252                         return False;
 253                 }
 254
 255                 /* Now that we are authenticated, got back to the generic session key... */
 256                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 257                 return True;
 258         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 259                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 260                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 261                 return True;
 262         } else {
 263                 DEBUG(2, ("Failed to finish dcesrv auth alter_ack: %s\n", nt_errstr(status)));
 264                 return True;
 265         }
 266 }
 267
 268 /*
 269   generate a CONNECT level verifier
 270 */
 271 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 272 {
 273         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 274         if (blob->data == NULL) {
 275                 return NT_STATUS_NO_MEMORY;
 276         }
 277         SIVAL(blob->data, 0, 1);
 278         memset(blob->data+4, 0, 12);
 279         return NT_STATUS_OK;
 280 }
 281
 282 /*
 283   generate a CONNECT level verifier
 284 */
 285 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 286 {
 287         if (blob->length != 16 ||
 288             IVAL(blob->data, 0) != 1) {
 289                 return NT_STATUS_ACCESS_DENIED;
 290         }
 291         return NT_STATUS_OK;
 292 }
 293
 294
 295 /*
 296   check credentials on a request
 297 */
 298 BOOL dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 299 {
 300         struct dcerpc_packet *pkt = &call->pkt;
 301         struct dcesrv_connection *dce_conn = call->conn;
 302         DATA_BLOB auth_blob;
 303         struct dcerpc_auth auth;
 304         struct ndr_pull *ndr;
 305         NTSTATUS status;
 306
 307         if (!dce_conn->auth_state.auth_info ||
 308             !dce_conn->auth_state.gensec_security) {
 309                 return True;
 310         }
 311
 312         auth_blob.length = 8 + pkt->auth_length;
 313
 314         /* check for a valid length */
 315         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 316                 return False;
 317         }
 318
 319         auth_blob.data =
 320                 pkt->u.request.stub_and_verifier.data +
 321                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 322         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 323
 324         /* pull the auth structure */
 325         ndr = ndr_pull_init_blob(&auth_blob, call);
 326         if (!ndr) {
 327                 return False;
 328         }
 329
 330         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 331                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 332         }
 333
 334         status = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 335         if (!NT_STATUS_IS_OK(status)) {
 336                 talloc_free(ndr);
 337                 return False;
 338         }
 339
 340         /* check signature or unseal the packet */
 341         switch (dce_conn->auth_state.auth_info->auth_level) {
 342         case DCERPC_AUTH_LEVEL_PRIVACY:
 343                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 344                                               call,
 345                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 346                                               pkt->u.request.stub_and_verifier.length,
 347                                               full_packet->data,
 348                                               full_packet->length-auth.credentials.length,
 349                                               &auth.credentials);
 350                 memcpy(pkt->u.request.stub_and_verifier.data,
 351                        full_packet->data + DCERPC_REQUEST_LENGTH,
 352                        pkt->u.request.stub_and_verifier.length);
 353                 break;
 354
 355         case DCERPC_AUTH_LEVEL_INTEGRITY:
 356                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 357                                              call,
 358                                              pkt->u.request.stub_and_verifier.data,
 359                                              pkt->u.request.stub_and_verifier.length,
 360                                              full_packet->data,
 361                                              full_packet->length-auth.credentials.length,
 362                                              &auth.credentials);
 363                 break;
 364
 365         case DCERPC_AUTH_LEVEL_CONNECT:
 366                 status = dcesrv_check_connect_verifier(&auth.credentials);
 367                 break;
 368
 369         default:
 370                 status = NT_STATUS_INVALID_LEVEL;
 371                 break;
 372         }
 373
 374         /* remove the indicated amount of padding */
 375         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 376                 talloc_free(ndr);
 377                 return False;
 378         }
 379         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 380         talloc_free(ndr);
 381
 382         return NT_STATUS_IS_OK(status);
 383 }
 384
 385
 386 /*
 387    push a signed or sealed dcerpc request packet into a blob
 388 */
 389 BOOL dcesrv_auth_response(struct dcesrv_call_state *call,
 390                           DATA_BLOB *blob, struct dcerpc_packet *pkt)
 391 {
 392         struct dcesrv_connection *dce_conn = call->conn;
 393         NTSTATUS status;
 394         struct ndr_push *ndr;
 395         uint32_t payload_length;
 396
 397         /* non-signed packets are simple */
 398         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 399                 status = dcerpc_push_auth(blob, call, pkt, NULL);
 400                 return NT_STATUS_IS_OK(status);
 401         }
 402
 403         ndr = ndr_push_init_ctx(call);
 404         if (!ndr) {
 405                 return False;
 406         }
 407
 408         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 409                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 410         }
 411
 412         status = ndr_push_dcerpc_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 413         if (!NT_STATUS_IS_OK(status)) {
 414                 return False;
 415         }
 416
 417         /* pad to 8 byte multiple */
 418         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 8);
 419         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 420
 421         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 422
 423         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 424                 status = dcesrv_connect_verifier(call,
 425                                                  &dce_conn->auth_state.auth_info->credentials);
 426                 if (!NT_STATUS_IS_OK(status)) {
 427                         return False;
 428                 }
 429         } else {
 430                 dce_conn->auth_state.auth_info->credentials
 431                         = data_blob_talloc(call, NULL,
 432                                            gensec_sig_size(dce_conn->auth_state.gensec_security));
 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 }