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                 return True;
 132         } else if (NT_STATUS_EQUAL(status, NT_STATUS_MORE_PROCESSING_REQUIRED)) {
 133                 dce_conn->auth_state.auth_info->auth_pad_length = 0;
 134                 dce_conn->auth_state.auth_info->auth_reserved = 0;
 135                 return True;
 136         } else {
 137                 DEBUG(2, ("Failed to start dcesrv auth negotiate: %s\n", nt_errstr(status)));
 138                 return False;
 139         }
 140 }
 141
 142
 143 /*
 144   process the final stage of a auth request
 145 */
 146 BOOL dcesrv_auth_auth3(struct dcesrv_call_state *call)
 147 {
 148         struct dcerpc_packet *pkt = &call->pkt;
 149         struct dcesrv_connection *dce_conn = call->conn;
 150         NTSTATUS status;
 151
 152         /* We can't work without an existing gensec state, and an new blob to feed it */
 153         if (!dce_conn->auth_state.auth_info ||
 154             !dce_conn->auth_state.gensec_security ||
 155             pkt->u.auth.auth_info.length == 0) {
 156                 return False;
 157         }
 158
 159         status = ndr_pull_struct_blob(&pkt->u.auth.auth_info,
 160                                       call->mem_ctx,
 161                                       dce_conn->auth_state.auth_info,
 162                                       (ndr_pull_flags_fn_t)ndr_pull_dcerpc_auth);
 163         if (!NT_STATUS_IS_OK(status)) {
 164                 return False;
 165         }
 166
 167         /* Pass the extra data we got from the client down to gensec for processing */
 168         status = gensec_update(dce_conn->auth_state.gensec_security,
 169                                call->mem_ctx,
 170                                dce_conn->auth_state.auth_info->credentials,
 171                                &dce_conn->auth_state.auth_info->credentials);
 172         if (NT_STATUS_IS_OK(status)) {
 173                 status = gensec_session_info(dce_conn->auth_state.gensec_security,
 174                                              &dce_conn->auth_state.session_info);
 175                 if (!NT_STATUS_IS_OK(status)) {
 176                         DEBUG(1, ("Failed to establish session_info: %s\n", nt_errstr(status)));
 177                         return False;
 178                 }
 179                 return True;
 180         } else {
 181                 DEBUG(4, ("dcesrv_auth_auth3: failed to authenticate: %s\n",
 182                           nt_errstr(status)));
 183                 return False;
 184         }
 185
 186         return True;
 187 }
 188
 189 /*
 190   check credentials on a request
 191 */
 192 BOOL dcesrv_auth_request(struct dcesrv_call_state *call, DATA_BLOB *full_packet)
 193 {
 194         struct dcerpc_packet *pkt = &call->pkt;
 195         struct dcesrv_connection *dce_conn = call->conn;
 196         DATA_BLOB auth_blob;
 197         struct dcerpc_auth auth;
 198         struct ndr_pull *ndr;
 199         NTSTATUS status;
 200
 201         if (!dce_conn->auth_state.auth_info ||
 202             !dce_conn->auth_state.gensec_security) {
 203                 return True;
 204         }
 205
 206         auth_blob.length = 8 + pkt->auth_length;
 207
 208         /* check for a valid length */
 209         if (pkt->u.request.stub_and_verifier.length < auth_blob.length) {
 210                 return False;
 211         }
 212
 213         auth_blob.data =
 214                 pkt->u.request.stub_and_verifier.data +
 215                 pkt->u.request.stub_and_verifier.length - auth_blob.length;
 216         pkt->u.request.stub_and_verifier.length -= auth_blob.length;
 217
 218         /* pull the auth structure */
 219         ndr = ndr_pull_init_blob(&auth_blob, call->mem_ctx);
 220         if (!ndr) {
 221                 return False;
 222         }
 223
 224         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 225                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 226         }
 227
 228         status = ndr_pull_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, &auth);
 229         if (!NT_STATUS_IS_OK(status)) {
 230                 return False;
 231         }
 232
 233         /* check signature or unseal the packet */
 234         switch (dce_conn->auth_state.auth_info->auth_level) {
 235         case DCERPC_AUTH_LEVEL_PRIVACY:
 236                 status = gensec_unseal_packet(dce_conn->auth_state.gensec_security,
 237                                               call->mem_ctx,
 238                                               pkt->u.request.stub_and_verifier.data,
 239                                               pkt->u.request.stub_and_verifier.length,
 240                                               full_packet->data,
 241                                               full_packet->length-auth.credentials.length,
 242                                               &auth.credentials);
 243                 break;
 244
 245         case DCERPC_AUTH_LEVEL_INTEGRITY:
 246                 status = gensec_check_packet(dce_conn->auth_state.gensec_security,
 247                                              call->mem_ctx,
 248                                              pkt->u.request.stub_and_verifier.data,
 249                                              pkt->u.request.stub_and_verifier.length,
 250                                              full_packet->data,
 251                                              full_packet->length-auth.credentials.length,
 252                                              &auth.credentials);
 253                 break;
 254
 255         default:
 256                 status = NT_STATUS_INVALID_LEVEL;
 257                 break;
 258         }
 259
 260         /* remove the indicated amount of padding */
 261         if (pkt->u.request.stub_and_verifier.length < auth.auth_pad_length) {
 262                 return False;
 263         }
 264         pkt->u.request.stub_and_verifier.length -= auth.auth_pad_length;
 265
 266         return NT_STATUS_IS_OK(status);
 267 }
 268
 269
 270 /*
 271    push a signed or sealed dcerpc request packet into a blob
 272 */
 273 BOOL dcesrv_auth_response(struct dcesrv_call_state *call,
 274                           DATA_BLOB *blob, struct dcerpc_packet *pkt)
 275 {
 276         struct dcesrv_connection *dce_conn = call->conn;
 277         NTSTATUS status;
 278         struct ndr_push *ndr;
 279
 280         /* non-signed packets are simple */
 281         if (!dce_conn->auth_state.auth_info || !dce_conn->auth_state.gensec_security) {
 282                 status = dcerpc_push_auth(blob, call->mem_ctx, pkt, NULL);
 283                 return NT_STATUS_IS_OK(status);
 284         }
 285
 286         ndr = ndr_push_init_ctx(call->mem_ctx);
 287         if (!ndr) {
 288                 return False;
 289         }
 290
 291         if (!(pkt->drep[0] & DCERPC_DREP_LE)) {
 292                 ndr->flags |= LIBNDR_FLAG_BIGENDIAN;
 293         }
 294
 295         status = ndr_push_dcerpc_packet(ndr, NDR_SCALARS|NDR_BUFFERS, pkt);
 296         if (!NT_STATUS_IS_OK(status)) {
 297                 return False;
 298         }
 299
 300         /* pad to 8 byte multiple */
 301         dce_conn->auth_state.auth_info->auth_pad_length = NDR_ALIGN(ndr, 8);
 302         ndr_push_zero(ndr, dce_conn->auth_state.auth_info->auth_pad_length);
 303
 304
 305         dce_conn->auth_state.auth_info->credentials
 306                 = data_blob_talloc(call->mem_ctx, NULL,
 307                                    gensec_sig_size(dce_conn->auth_state.gensec_security));
 308
 309         /* add the auth verifier */
 310         status = ndr_push_dcerpc_auth(ndr, NDR_SCALARS|NDR_BUFFERS, dce_conn->auth_state.auth_info);
 311         if (!NT_STATUS_IS_OK(status)) {
 312                 return False;
 313         }
 314
 315         /* extract the whole packet as a blob */
 316         *blob = ndr_push_blob(ndr);
 317
 318         /* fill in the fragment length and auth_length, we can't fill
 319            in these earlier as we don't know the signature length (it
 320            could be variable length) */
 321         dcerpc_set_frag_length(blob, blob->length);
 322         dcerpc_set_auth_length(blob, dce_conn->auth_state.auth_info->credentials.length);
 323
 324         /* sign or seal the packet */
 325         switch (dce_conn->auth_state.auth_info->auth_level) {
 326         case DCERPC_AUTH_LEVEL_PRIVACY:
 327                 status = gensec_seal_packet(dce_conn->auth_state.gensec_security,
 328                                             call->mem_ctx,
 329                                             ndr->data + DCERPC_REQUEST_LENGTH,
 330                                             ndr->offset - DCERPC_REQUEST_LENGTH,
 331                                             blob->data,
 332                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 333                                               &dce_conn->auth_state.auth_info->credentials);
 334                 break;
 335
 336         case DCERPC_AUTH_LEVEL_INTEGRITY:
 337                 status = gensec_sign_packet(dce_conn->auth_state.gensec_security,
 338                                             call->mem_ctx,
 339                                             ndr->data + DCERPC_REQUEST_LENGTH,
 340                                             ndr->offset - DCERPC_REQUEST_LENGTH,
 341                                             blob->data,
 342                                             blob->length - dce_conn->auth_state.auth_info->credentials.length,
 343                                             &dce_conn->auth_state.auth_info->credentials);
 344
 345                 break;
 346         default:
 347                 status = NT_STATUS_INVALID_LEVEL;
 348                 break;
 349         }
 350
 351         if (!NT_STATUS_IS_OK(status)) {
 352                 return False;
 353         }
 354
 355         memcpy(blob->data + blob->length - dce_conn->auth_state.auth_info->credentials.length,
 356                dce_conn->auth_state.auth_info->credentials.data, dce_conn->auth_state.auth_info->credentials.length);
 357
 358         data_blob_free(&dce_conn->auth_state.auth_info->credentials);
 359
 360         return True;
 361 }