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