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
  26 /*
  27   startup the cryptographic side of an authenticated dcerpc server
  28 */
  29 NTSTATUS dcesrv_crypto_select_type(struct dcesrv_connection *dce_conn,
  30                                struct dcesrv_auth *auth)
  31 {
  32         NTSTATUS status;
  33         if (auth->auth_info->auth_level != DCERPC_AUTH_LEVEL_INTEGRITY &&
  34             auth->auth_info->auth_level != DCERPC_AUTH_LEVEL_PRIVACY &&
  35             auth->auth_info->auth_level != DCERPC_AUTH_LEVEL_CONNECT) {
  36                 DEBUG(2,("auth_level %d not supported in dcesrv auth\n",
  37                          auth->auth_info->auth_level));
  38                 return NT_STATUS_INVALID_PARAMETER;
  39         }
  40
  41         if (auth->gensec_security != NULL) {
  42                 /* TODO:
  43                  * this this function should not be called
  44                  * twice per dcesrv_connection!
  45                  *
  46                  * so we need to find out the right
  47                  * dcerpc error to return
  48                  */
  49         }
  50
  51         status = gensec_server_start(&auth->gensec_security);
  52         if (!NT_STATUS_IS_OK(status)) {
  53                 DEBUG(1, ("Failed to start GENSEC server code: %s\n", nt_errstr(status)));
  54                 return status;
  55         }
  56
  57         status = gensec_start_mech_by_authtype(auth->gensec_security, auth->auth_info->auth_type,
  58                                                auth->auth_info->auth_level);
  59
  60         if (!NT_STATUS_IS_OK(status)) {
  61                 DEBUG(1, ("Failed to start GENSEC mech-specific server code (%d): %s\n",
  62                           (int)auth->auth_info->auth_type,
  63                           nt_errstr(status)));
  64                 return status;
  65         }
  66
  67         return status;
  68 }
  69
  70 /*
  71   parse any auth information from a dcerpc bind request
  72   return False if we can't handle the auth request for some
  73   reason (in which case we send a bind_nak)
  74 */
  75 BOOL dcesrv_auth_bind(struct dcesrv_call_state *call)
  76 {
  77         struct dcerpc_packet *pkt = &call->pkt;
  78         struct dcesrv_connection *dce_conn = call->conn;
  79         NTSTATUS status;
  80
  81         if (pkt->u.bind.auth_info.length == 0) {
  82                 dce_conn->auth_state.auth_info = NULL;
  83                 return True;
  84         }
  85
  86         dce_conn->auth_state.auth_info = talloc_p(dce_conn, struct dcerpc_auth);
  87         if (!dce_conn->auth_state.auth_info) {
  88                 return False;
  89         }
  90
  91         status = ndr_pull_struct_blob(&pkt->u.bind.auth_info,
  92                                       call,
  93                                       dce_conn->auth_state.auth_info,
  94                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
  95         if (!NT_STATUS_IS_OK(status)) {
  96                 return False;
  97         }
  98
  99         status = dcesrv_crypto_select_type(dce_conn, &dce_conn->auth_state);
 100         if (!NT_STATUS_IS_OK(status)) {
 101                 return False;
 102         }
 103
 104         return True;
 105 }
 106
 107 /*
 108   add any auth information needed in a bind ack, and process the authentication
 109   information found in the bind.
 110 */
 111 BOOL dcesrv_auth_bind_ack(struct dcesrv_call_state *call, struct dcerpc_packet *pkt)
 112 {
 113         struct dcesrv_connection *dce_conn = call->conn;
 114         NTSTATUS status;
 115
 116         if (!call->conn->auth_state.gensec_security) {
 117                 return True;
 118         }
 119
 120         status = gensec_update(dce_conn->auth_state.gensec_security,
 121                                call,
 122                                dce_conn->auth_state.auth_info->credentials,
 123                                &dce_conn->auth_state.auth_info->credentials);
 124
 125         if (NT_STATUS_IS_OK(status)) {
 126                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 127                                              &dce_conn->auth_state.session_info);
 128                 if (!NT_STATUS_IS_OK(status)) {
 129                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 130                         return False;
 131                 }
 132
 133                 /* Now that we are authenticated, got back to the generic session key... */
 134                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 135                 return True;
 136         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 137                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 138                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 139                 return True;
 140         } else {
 141                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 142                 return False;
 143         }
 144 }
 145
 146
 147 /*
 148   process the final stage of a auth request
 149 */
 150 BOOL dcesrv_auth_auth3(struct dcesrv_call_state *call)
 151 {
 152         struct dcerpc_packet *pkt = &call->pkt;
 153         struct dcesrv_connection *dce_conn = call->conn;
 154         NTSTATUS status;
 155
 156         /* We can't work without an existing gensec state, and an new blob to feed it */
 157         if (!dce_conn->auth_state.auth_info ||
 158             !dce_conn->auth_state.gensec_security ||
 159             pkt->u.auth.auth_info.length == 0) {
 160                 return False;
 161         }
 162
 163         status = ndr_pull_struct_blob(&pkt->u.auth.auth_info,
 164                                       call,
 165                                       dce_conn->auth_state.auth_info,
 166                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 167         if (!NT_STATUS_IS_OK(status)) {
 168                 return False;
 169         }
 170
 171         /* Pass the extra data we got from the client down to gensec for processing */
 172         status = gensec_update(dce_conn->auth_state.gensec_security,
 173                                call,
 174                                dce_conn->auth_state.auth_info->credentials,
 175                                &dce_conn->auth_state.auth_info->credentials);
 176         if (NT_STATUS_IS_OK(status)) {
 177                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 178                                              &dce_conn->auth_state.session_info);
 179                 if (!NT_STATUS_IS_OK(status)) {
 180                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 181                         return False;
 182                 }
 183                 /* Now that we are authenticated, got back to the generic session key... */
 184                 dce_conn->auth_state.session_key = dcesrv_generic_session_key;
 185                 return True;
 186         } else {
 187                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 188                           nt_errstr(status)));
 189                 return False;
 190         }
 191
 192         return True;
 193 }
 194
 195
 196 /*
 197   generate a CONNECT level verifier
 198 */
 199 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 200 {
 201         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 202         if (blob->data == NULL) {
 203                 return NT_STATUS_NO_MEMORY;
 204         }
 205         SIVAL(blob->data, 0, 1);
 206         memset(blob->data+4, 0, 12);
 207         return NT_STATUS_OK;
 208 }
 209
 210 /*
 211   generate a CONNECT level verifier
 212 */
 213 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 214 {
 215         if (blob->length != 16 ||
 216             IVAL(blob->data, 0) != 1) {
 217                 return NT_STATUS_ACCESS_DENIED;
 218         }
 219         return NT_STATUS_OK;
 220 }
 221
 222
 223 /*
 224   check credentials on a request
 225 */
 226 BOOL dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 227 {
 228         struct dcerpc_packet *pkt = &call->pkt;
 229         struct dcesrv_connection *dce_conn = call->conn;
 230         DATA_BLOB auth_blob;
 231         struct dcerpc_auth auth;
 232         struct ndr_pull *ndr;
 233         NTSTATUS status;
 234
 235         if (!dce_conn->auth_state.auth_info ||
 236             !dce_conn->auth_state.gensec_security) {
 237                 return True;
 238         }
 239
 240         auth_blob.length = 8 + pkt->auth_length;
 241
 242         /* check for a valid length */
 243         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 244                 return False;
 245         }
 246
 247         auth_blob.data =
 248                 pkt->u.request.stub_and_verifier.data +
 249                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 250         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 251
 252         /* pull the auth structure */
 253         ndr = ndr_pull_init_blob(&auth_blob, call);
 254         if (!ndr) {
 255                 return False;
 256         }
 257
 258         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 259                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 260         }
 261
 262         status = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 263         if (!NT_STATUS_IS_OK(status)) {
 264                 talloc_free(ndr);
 265                 return False;
 266         }
 267
 268         /* check signature or unseal the packet */
 269         switch (dce_conn->auth_state.auth_info->auth_level) {
 270         case DCERPC_AUTH_LEVEL_PRIVACY:
 271                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 272                                               call,
 273                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 274                                               pkt->u.request.stub_and_verifier.length,
 275                                               full_packet->data,
 276                                               full_packet->length-auth.credentials.length,
 277                                               &auth.credentials);
 278                 memcpy(pkt->u.request.stub_and_verifier.data,
 279                        full_packet->data + DCERPC_REQUEST_LENGTH,
 280                        pkt->u.request.stub_and_verifier.length);
 281                 break;
 282
 283         case DCERPC_AUTH_LEVEL_INTEGRITY:
 284                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 285                                              call,
 286                                              pkt->u.request.stub_and_verifier.data,
 287                                              pkt->u.request.stub_and_verifier.length,
 288                                              full_packet->data,
 289                                              full_packet->length-auth.credentials.length,
 290                                              &auth.credentials);
 291                 break;
 292
 293         case DCERPC_AUTH_LEVEL_CONNECT:
 294                 status = dcesrv_check_connect_verifier(&auth.credentials);
 295                 break;
 296
 297         default:
 298                 status = NT_STATUS_INVALID_LEVEL;
 299                 break;
 300         }
 301
 302         /* remove the indicated amount of padding */
 303         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 304                 talloc_free(ndr);
 305                 return False;
 306         }
 307         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 308         talloc_free(ndr);
 309
 310         return NT_STATUS_IS_OK(status);
 311 }
 312
 313
 314 /*
 315    push a signed or sealed dcerpc request packet into a blob
 316 */
 317 BOOL dcesrv_auth_response(struct dcesrv_call_state *call,
 318                           DATA_BLOB *blob, struct dcerpc_packet *pkt)
 319 {
 320         struct dcesrv_connection *dce_conn = call->conn;
 321         NTSTATUS status;
 322         struct ndr_push *ndr;
 323         uint32_t payload_length;
 324
 325         /* non-signed packets are simple */
 326         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 327                 status = dcerpc_push_auth(blob, call, pkt, NULL);
 328                 return NT_STATUS_IS_OK(status);
 329         }
 330
 331         ndr = ndr_push_init_ctx(call);
 332         if (!ndr) {
 333                 return False;
 334         }
 335
 336         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 337                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 338         }
 339
 340         status = ndr_push_dcerpc_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 341         if (!NT_STATUS_IS_OK(status)) {
 342                 return False;
 343         }
 344
 345         /* pad to 8 byte multiple */
 346         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 8);
 347         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 348
 349         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 350
 351         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 352                 status = dcesrv_connect_verifier(call,
 353                                                  &dce_conn->auth_state.auth_info->credentials);
 354                 if (!NT_STATUS_IS_OK(status)) {
 355                         return False;
 356                 }
 357         } else {
 358                 dce_conn->auth_state.auth_info->credentials
 359                         = data_blob_talloc(call, NULL,
 360                                            gensec_sig_size(dce_conn->auth_state.gensec_security));
 361         }
 362
 363         /* add the auth verifier */
 364         status = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, dce_conn->auth_state.auth_info);
 365         if (!NT_STATUS_IS_OK(status)) {
 366                 return False;
 367         }
 368
 369         /* extract the whole packet as a blob */
 370         *blob = ndr_push_blob(ndr);
 371
 372         /* fill in the fragment length and auth_length, we can't fill
 373            in these earlier as we don't know the signature length (it
 374            could be variable length) */
 375         dcerpc_set_frag_length(blob, blob->length);
 376         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 377
 378         /* sign or seal the packet */
 379         switch (dce_conn->auth_state.auth_info->auth_level) {
 380         case DCERPC_AUTH_LEVEL_PRIVACY:
 381                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 382                                             call,
 383                                             ndr->data + DCERPC_REQUEST_LENGTH,
 384                                             payload_length,
 385                                             blob->data,
 386                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 387                                             &dce_conn->auth_state.auth_info->credentials);
 388                 break;
 389
 390         case DCERPC_AUTH_LEVEL_INTEGRITY:
 391                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 392                                             call,
 393                                             ndr->data + DCERPC_REQUEST_LENGTH,
 394                                             payload_length,
 395                                             blob->data,
 396                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 397                                             &dce_conn->auth_state.auth_info->credentials);
 398
 399                 break;
 400
 401         case DCERPC_AUTH_LEVEL_CONNECT:
 402                 break;
 403
 404         default:
 405                 status = NT_STATUS_INVALID_LEVEL;
 406                 break;
 407         }
 408
 409         if (!NT_STATUS_IS_OK(status)) {
 410                 return False;
 411         }
 412
 413         memcpy(blob->data + blob->length - dce_conn->auth_state.auth_info->credentials.length,
 414                dce_conn->auth_state.auth_info->credentials.data, dce_conn->auth_state.auth_info->credentials.length);
 415
 416         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 417
 418         return True;
 419 }