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