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.auth.auth_info.length == 0) {
 161                 return False;
 162         }
 163
 164         status = ndr_pull_struct_blob(&pkt->u.auth.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 /*
 198   generate a CONNECT level verifier
 199 */
 200 static NTSTATUS dcesrv_connect_verifier(TALLOC_CTX *mem_ctx, DATA_BLOB *blob)
 201 {
 202         *blob = data_blob_talloc(mem_ctx, NULL, 16);
 203         if (blob->data == NULL) {
 204                 return NT_STATUS_NO_MEMORY;
 205         }
 206         SIVAL(blob->data, 0, 1);
 207         memset(blob->data+4, 0, 12);
 208         return NT_STATUS_OK;
 209 }
 210
 211 /*
 212   generate a CONNECT level verifier
 213 */
 214 static NTSTATUS dcesrv_check_connect_verifier(DATA_BLOB *blob)
 215 {
 216         if (blob->length != 16 ||
 217             IVAL(blob->data, 0) != 1) {
 218                 return NT_STATUS_ACCESS_DENIED;
 219         }
 220         return NT_STATUS_OK;
 221 }
 222
 223
 224 /*
 225   check credentials on a request
 226 */
 227 BOOL dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 228 {
 229         struct dcerpc_packet *pkt = &call->pkt;
 230         struct dcesrv_connection *dce_conn = call->conn;
 231         DATA_BLOB auth_blob;
 232         struct dcerpc_auth auth;
 233         struct ndr_pull *ndr;
 234         NTSTATUS status;
 235
 236         if (!dce_conn->auth_state.auth_info ||
 237             !dce_conn->auth_state.gensec_security) {
 238                 return True;
 239         }
 240
 241         auth_blob.length = 8 + pkt->auth_length;
 242
 243         /* check for a valid length */
 244         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 245                 return False;
 246         }
 247
 248         auth_blob.data =
 249                 pkt->u.request.stub_and_verifier.data +
 250                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 251         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 252
 253         /* pull the auth structure */
 254         ndr = ndr_pull_init_blob(&auth_blob, call);
 255         if (!ndr) {
 256                 return False;
 257         }
 258
 259         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 260                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 261         }
 262
 263         status = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 264         if (!NT_STATUS_IS_OK(status)) {
 265                 talloc_free(ndr);
 266                 return False;
 267         }
 268
 269         /* check signature or unseal the packet */
 270         switch (dce_conn->auth_state.auth_info->auth_level) {
 271         case DCERPC_AUTH_LEVEL_PRIVACY:
 272                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 273                                               call,
 274                                               full_packet->data + DCERPC_REQUEST_LENGTH,
 275                                               pkt->u.request.stub_and_verifier.length,
 276                                               full_packet->data,
 277                                               full_packet->length-auth.credentials.length,
 278                                               &auth.credentials);
 279                 memcpy(pkt->u.request.stub_and_verifier.data,
 280                        full_packet->data + DCERPC_REQUEST_LENGTH,
 281                        pkt->u.request.stub_and_verifier.length);
 282                 break;
 283
 284         case DCERPC_AUTH_LEVEL_INTEGRITY:
 285                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 286                                              call,
 287                                              pkt->u.request.stub_and_verifier.data,
 288                                              pkt->u.request.stub_and_verifier.length,
 289                                              full_packet->data,
 290                                              full_packet->length-auth.credentials.length,
 291                                              &auth.credentials);
 292                 break;
 293
 294         case DCERPC_AUTH_LEVEL_CONNECT:
 295                 status = dcesrv_check_connect_verifier(&auth.credentials);
 296                 break;
 297
 298         default:
 299                 status = NT_STATUS_INVALID_LEVEL;
 300                 break;
 301         }
 302
 303         /* remove the indicated amount of padding */
 304         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 305                 talloc_free(ndr);
 306                 return False;
 307         }
 308         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 309         talloc_free(ndr);
 310
 311         return NT_STATUS_IS_OK(status);
 312 }
 313
 314
 315 /*
 316    push a signed or sealed dcerpc request packet into a blob
 317 */
 318 BOOL dcesrv_auth_response(struct dcesrv_call_state *call,
 319                           DATA_BLOB *blob, struct dcerpc_packet *pkt)
 320 {
 321         struct dcesrv_connection *dce_conn = call->conn;
 322         NTSTATUS status;
 323         struct ndr_push *ndr;
 324         uint32_t payload_length;
 325
 326         /* non-signed packets are simple */
 327         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 328                 status = dcerpc_push_auth(blob, call, pkt, NULL);
 329                 return NT_STATUS_IS_OK(status);
 330         }
 331
 332         ndr = ndr_push_init_ctx(call);
 333         if (!ndr) {
 334                 return False;
 335         }
 336
 337         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 338                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 339         }
 340
 341         status = ndr_push_dcerpc_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 342         if (!NT_STATUS_IS_OK(status)) {
 343                 return False;
 344         }
 345
 346         /* pad to 8 byte multiple */
 347         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 8);
 348         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 349
 350         payload_length = ndr->offset - DCERPC_REQUEST_LENGTH;
 351
 352         if (dce_conn->auth_state.auth_info->auth_level == DCERPC_AUTH_LEVEL_CONNECT) {
 353                 status = dcesrv_connect_verifier(call,
 354                                                  &dce_conn->auth_state.auth_info->credentials);
 355                 if (!NT_STATUS_IS_OK(status)) {
 356                         return False;
 357                 }
 358         } else {
 359                 dce_conn->auth_state.auth_info->credentials
 360                         = data_blob_talloc(call, NULL,
 361                                            gensec_sig_size(dce_conn->auth_state.gensec_security));
 362         }
 363
 364         /* add the auth verifier */
 365         status = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, dce_conn->auth_state.auth_info);
 366         if (!NT_STATUS_IS_OK(status)) {
 367                 return False;
 368         }
 369
 370         /* extract the whole packet as a blob */
 371         *blob = ndr_push_blob(ndr);
 372
 373         /* fill in the fragment length and auth_length, we can't fill
 374            in these earlier as we don't know the signature length (it
 375            could be variable length) */
 376         dcerpc_set_frag_length(blob, blob->length);
 377         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 378
 379         /* sign or seal the packet */
 380         switch (dce_conn->auth_state.auth_info->auth_level) {
 381         case DCERPC_AUTH_LEVEL_PRIVACY:
 382                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 383                                             call,
 384                                             ndr->data + DCERPC_REQUEST_LENGTH,
 385                                             payload_length,
 386                                             blob->data,
 387                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 388                                             &dce_conn->auth_state.auth_info->credentials);
 389                 break;
 390
 391         case DCERPC_AUTH_LEVEL_INTEGRITY:
 392                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 393                                             call,
 394                                             ndr->data + DCERPC_REQUEST_LENGTH,
 395                                             payload_length,
 396                                             blob->data,
 397                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 398                                             &dce_conn->auth_state.auth_info->credentials);
 399
 400                 break;
 401
 402         case DCERPC_AUTH_LEVEL_CONNECT:
 403                 break;
 404
 405         default:
 406                 status = NT_STATUS_INVALID_LEVEL;
 407                 break;
 408         }
 409
 410         if (!NT_STATUS_IS_OK(status)) {
 411                 return False;
 412         }
 413
 414         memcpy(blob->data + blob->length - dce_conn->auth_state.auth_info->credentials.length,
 415                dce_conn->auth_state.auth_info->credentials.data, dce_conn->auth_state.auth_info->credentials.length);
 416
 417         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 418
 419         return True;
 420 }