source4/librpc/rpc/dcerpc_schannel.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    dcerpc schannel operations
   5
   6    Copyright (C) Andrew Tridgell 2004
   7    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2004-2005
   8    Copyright (C) Rafal Szczesniak 2006
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include <tevent.h>
  26 #include "auth/auth.h"
  27 #include "libcli/composite/composite.h"
  28 #include "libcli/auth/libcli_auth.h"
  29 #include "librpc/gen_ndr/ndr_netlogon.h"
  30 #include "librpc/gen_ndr/ndr_netlogon_c.h"
  31 #include "auth/credentials/credentials.h"
  32 #include "librpc/rpc/dcerpc_proto.h"
  33 #include "param/param.h"
  34
  35 struct schannel_key_state {
  36         struct dcerpc_pipe *pipe;
  37         struct dcerpc_pipe *pipe2;
  38         struct dcerpc_binding *binding;
  39         bool dcerpc_schannel_auto;
  40         struct cli_credentials *credentials;
  41         struct netlogon_creds_CredentialState *creds;
  42         uint32_t local_negotiate_flags;
  43         uint32_t remote_negotiate_flags;
  44         struct netr_Credential credentials1;
  45         struct netr_Credential credentials2;
  46         struct netr_Credential credentials3;
  47         struct netr_ServerReqChallenge r;
  48         struct netr_ServerAuthenticate2 a;
  49         const struct samr_Password *mach_pwd;
  50 };
  51
  52
  53 static void continue_secondary_connection(struct composite_context *ctx);
  54 static void continue_bind_auth_none(struct composite_context *ctx);
  55 static void continue_srv_challenge(struct tevent_req *subreq);
  56 static void continue_srv_auth2(struct tevent_req *subreq);
  57
  58
  59 /*
  60   Stage 2 of schannel_key: Receive endpoint mapping and request secondary
  61   rpc connection
  62 */
  63 static void continue_epm_map_binding(struct composite_context *ctx)
  64 {
  65         struct composite_context *c;
  66         struct schannel_key_state *s;
  67         struct composite_context *sec_conn_req;
  68
  69         c = talloc_get_type(ctx->async.private_data, struct composite_context);
  70         s = talloc_get_type(c->private_data, struct schannel_key_state);
  71
  72         /* receive endpoint mapping */
  73         c->status = dcerpc_epm_map_binding_recv(ctx);
  74         if (!NT_STATUS_IS_OK(c->status)) {
  75                 DEBUG(0,("Failed to map DCERPC/TCP NCACN_NP pipe for '%s' - %s\n",
  76                          NDR_NETLOGON_UUID, nt_errstr(c->status)));
  77                 composite_error(c, c->status);
  78                 return;
  79         }
  80
  81         /* send a request for secondary rpc connection */
  82         sec_conn_req = dcerpc_secondary_connection_send(s->pipe,
  83                                                         s->binding);
  84         if (composite_nomem(sec_conn_req, c)) return;
  85
  86         composite_continue(c, sec_conn_req, continue_secondary_connection, c);
  87 }
  88
  89
  90 /*
  91   Stage 3 of schannel_key: Receive secondary rpc connection and perform
  92   non-authenticated bind request
  93 */
  94 static void continue_secondary_connection(struct composite_context *ctx)
  95 {
  96         struct composite_context *c;
  97         struct schannel_key_state *s;
  98         struct composite_context *auth_none_req;
  99
 100         c = talloc_get_type(ctx->async.private_data, struct composite_context);
 101         s = talloc_get_type(c->private_data, struct schannel_key_state);
 102
 103         /* receive secondary rpc connection */
 104         c->status = dcerpc_secondary_connection_recv(ctx, &s->pipe2);
 105         if (!composite_is_ok(c)) return;
 106
 107         talloc_steal(s, s->pipe2);
 108
 109         /* initiate a non-authenticated bind */
 110         auth_none_req = dcerpc_bind_auth_none_send(c, s->pipe2, &ndr_table_netlogon);
 111         if (composite_nomem(auth_none_req, c)) return;
 112
 113         composite_continue(c, auth_none_req, continue_bind_auth_none, c);
 114 }
 115
 116
 117 /*
 118   Stage 4 of schannel_key: Receive non-authenticated bind and get
 119   a netlogon challenge
 120 */
 121 static void continue_bind_auth_none(struct composite_context *ctx)
 122 {
 123         struct composite_context *c;
 124         struct schannel_key_state *s;
 125         struct tevent_req *subreq;
 126
 127         c = talloc_get_type(ctx->async.private_data, struct composite_context);
 128         s = talloc_get_type(c->private_data, struct schannel_key_state);
 129
 130         /* receive result of non-authenticated bind request */
 131         c->status = dcerpc_bind_auth_none_recv(ctx);
 132         if (!composite_is_ok(c)) return;
 133
 134         /* prepare a challenge request */
 135         s->r.in.server_name   = talloc_asprintf(c, "\\\\%s", dcerpc_server_name(s->pipe));
 136         if (composite_nomem(s->r.in.server_name, c)) return;
 137         s->r.in.computer_name = cli_credentials_get_workstation(s->credentials);
 138         s->r.in.credentials   = &s->credentials1;
 139         s->r.out.return_credentials  = &s->credentials2;
 140
 141         generate_random_buffer(s->credentials1.data, sizeof(s->credentials1.data));
 142
 143         /*
 144           request a netlogon challenge - a rpc request over opened secondary pipe
 145         */
 146         subreq = dcerpc_netr_ServerReqChallenge_r_send(s, c->event_ctx,
 147                                                        s->pipe2->binding_handle,
 148                                                        &s->r);
 149         if (composite_nomem(subreq, c)) return;
 150
 151         tevent_req_set_callback(subreq, continue_srv_challenge, c);
 152 }
 153
 154
 155 /*
 156   Stage 5 of schannel_key: Receive a challenge and perform authentication
 157   on the netlogon pipe
 158 */
 159 static void continue_srv_challenge(struct tevent_req *subreq)
 160 {
 161         struct composite_context *c;
 162         struct schannel_key_state *s;
 163
 164         c = tevent_req_callback_data(subreq, struct composite_context);
 165         s = talloc_get_type(c->private_data, struct schannel_key_state);
 166
 167         /* receive rpc request result - netlogon challenge */
 168         c->status = dcerpc_netr_ServerReqChallenge_r_recv(subreq, s);
 169         TALLOC_FREE(subreq);
 170         if (!composite_is_ok(c)) return;
 171
 172         /* prepare credentials for auth2 request */
 173         s->mach_pwd = cli_credentials_get_nt_hash(s->credentials, c);
 174
 175         /* auth2 request arguments */
 176         s->a.in.server_name      = s->r.in.server_name;
 177         s->a.in.account_name     = cli_credentials_get_username(s->credentials);
 178         s->a.in.secure_channel_type =
 179                 cli_credentials_get_secure_channel_type(s->credentials);
 180         s->a.in.computer_name    = cli_credentials_get_workstation(s->credentials);
 181         s->a.in.negotiate_flags  = &s->local_negotiate_flags;
 182         s->a.in.credentials      = &s->credentials3;
 183         s->a.out.negotiate_flags = &s->remote_negotiate_flags;
 184         s->a.out.return_credentials     = &s->credentials3;
 185
 186         s->creds = netlogon_creds_client_init(s,
 187                                               s->a.in.account_name,
 188                                               s->a.in.computer_name,
 189                                               &s->credentials1, &s->credentials2,
 190                                               s->mach_pwd, &s->credentials3,
 191                                               s->local_negotiate_flags);
 192         if (composite_nomem(s->creds, c)) {
 193                 return;
 194         }
 195         /*
 196           authenticate on the netlogon pipe - a rpc request over secondary pipe
 197         */
 198         subreq = dcerpc_netr_ServerAuthenticate2_r_send(s, c->event_ctx,
 199                                                         s->pipe2->binding_handle,
 200                                                         &s->a);
 201         if (composite_nomem(subreq, c)) return;
 202
 203         tevent_req_set_callback(subreq, continue_srv_auth2, c);
 204 }
 205
 206
 207 /*
 208   Stage 6 of schannel_key: Receive authentication request result and verify
 209   received credentials
 210 */
 211 static void continue_srv_auth2(struct tevent_req *subreq)
 212 {
 213         struct composite_context *c;
 214         struct schannel_key_state *s;
 215
 216         c = tevent_req_callback_data(subreq, struct composite_context);
 217         s = talloc_get_type(c->private_data, struct schannel_key_state);
 218
 219         /* receive rpc request result - auth2 credentials */
 220         c->status = dcerpc_netr_ServerAuthenticate2_r_recv(subreq, s);
 221         TALLOC_FREE(subreq);
 222         if (!composite_is_ok(c)) return;
 223
 224         if (!NT_STATUS_EQUAL(s->a.out.result, NT_STATUS_ACCESS_DENIED) &&
 225             !NT_STATUS_IS_OK(s->a.out.result)) {
 226                 composite_error(c, s->a.out.result);
 227                 return;
 228         }
 229
 230         /*
 231          * Strong keys could be unsupported (NT4) or disables. So retry with the
 232          * flags returned by the server. - asn
 233          */
 234         if (NT_STATUS_EQUAL(s->a.out.result, NT_STATUS_ACCESS_DENIED)) {
 235                 uint32_t lf = s->local_negotiate_flags;
 236                 const char *ln = NULL;
 237                 uint32_t rf = s->remote_negotiate_flags;
 238                 const char *rn = NULL;
 239
 240                 if (!s->dcerpc_schannel_auto) {
 241                         composite_error(c, s->a.out.result);
 242                         return;
 243                 }
 244                 s->dcerpc_schannel_auto = false;
 245
 246                 if (lf & NETLOGON_NEG_SUPPORTS_AES)  {
 247                         ln = "aes";
 248                         if (rf & NETLOGON_NEG_SUPPORTS_AES) {
 249                                 composite_error(c, s->a.out.result);
 250                                 return;
 251                         }
 252                 } else if (lf & NETLOGON_NEG_STRONG_KEYS) {
 253                         ln = "strong";
 254                         if (rf & NETLOGON_NEG_STRONG_KEYS) {
 255                                 composite_error(c, s->a.out.result);
 256                                 return;
 257                         }
 258                 } else {
 259                         ln = "des";
 260                 }
 261
 262                 if (rf & NETLOGON_NEG_SUPPORTS_AES)  {
 263                         rn = "aes";
 264                 } else if (rf & NETLOGON_NEG_STRONG_KEYS) {
 265                         rn = "strong";
 266                 } else {
 267                         rn = "des";
 268                 }
 269
 270                 DEBUG(3, ("Server doesn't support %s keys, downgrade to %s"
 271                           "and retry! local[0x%08X] remote[0x%08X]\n",
 272                           ln, rn, lf, rf));
 273
 274                 s->local_negotiate_flags = s->remote_negotiate_flags;
 275
 276                 generate_random_buffer(s->credentials1.data,
 277                                        sizeof(s->credentials1.data));
 278
 279                 subreq = dcerpc_netr_ServerReqChallenge_r_send(s,
 280                                                                c->event_ctx,
 281                                                                s->pipe2->binding_handle,
 282                                                                &s->r);
 283                 if (composite_nomem(subreq, c)) return;
 284
 285                 tevent_req_set_callback(subreq, continue_srv_challenge, c);
 286                 return;
 287         }
 288
 289         s->creds->negotiate_flags = s->remote_negotiate_flags;
 290
 291         /* verify credentials */
 292         if (!netlogon_creds_client_check(s->creds, s->a.out.return_credentials)) {
 293                 composite_error(c, NT_STATUS_UNSUCCESSFUL);
 294                 return;
 295         }
 296
 297         /* setup current netlogon credentials */
 298         cli_credentials_set_netlogon_creds(s->credentials, s->creds);
 299
 300         composite_done(c);
 301 }
 302
 303
 304 /*
 305   Initiate establishing a schannel key using netlogon challenge
 306   on a secondary pipe
 307 */
 308 struct composite_context *dcerpc_schannel_key_send(TALLOC_CTX *mem_ctx,
 309                                                    struct dcerpc_pipe *p,
 310                                                    struct cli_credentials *credentials,
 311                                                    struct loadparm_context *lp_ctx)
 312 {
 313         struct composite_context *c;
 314         struct schannel_key_state *s;
 315         struct composite_context *epm_map_req;
 316         enum netr_SchannelType schannel_type = cli_credentials_get_secure_channel_type(credentials);
 317
 318         /* composite context allocation and setup */
 319         c = composite_create(mem_ctx, p->conn->event_ctx);
 320         if (c == NULL) return NULL;
 321
 322         s = talloc_zero(c, struct schannel_key_state);
 323         if (composite_nomem(s, c)) return c;
 324         c->private_data = s;
 325
 326         /* store parameters in the state structure */
 327         s->pipe        = p;
 328         s->credentials = credentials;
 329         s->local_negotiate_flags = NETLOGON_NEG_AUTH2_FLAGS;
 330
 331         /* allocate credentials */
 332         if (s->pipe->conn->flags & DCERPC_SCHANNEL_128) {
 333                 s->local_negotiate_flags = NETLOGON_NEG_AUTH2_ADS_FLAGS;
 334         }
 335         if (s->pipe->conn->flags & DCERPC_SCHANNEL_AES) {
 336                 s->local_negotiate_flags = NETLOGON_NEG_AUTH2_ADS_FLAGS;
 337                 s->local_negotiate_flags |= NETLOGON_NEG_SUPPORTS_AES;
 338         }
 339         if (s->pipe->conn->flags & DCERPC_SCHANNEL_AUTO) {
 340                 s->local_negotiate_flags = NETLOGON_NEG_AUTH2_ADS_FLAGS;
 341                 s->local_negotiate_flags |= NETLOGON_NEG_SUPPORTS_AES;
 342                 s->dcerpc_schannel_auto = true;
 343         }
 344
 345         /* type of authentication depends on schannel type */
 346         if (schannel_type == SEC_CHAN_RODC) {
 347                 s->local_negotiate_flags |= NETLOGON_NEG_RODC_PASSTHROUGH;
 348         }
 349
 350         /* allocate binding structure */
 351         s->binding = talloc_zero(c, struct dcerpc_binding);
 352         if (composite_nomem(s->binding, c)) return c;
 353
 354         *s->binding = *s->pipe->binding;
 355
 356         /* request the netlogon endpoint mapping */
 357         epm_map_req = dcerpc_epm_map_binding_send(c, s->binding,
 358                                                   &ndr_table_netlogon,
 359                                                   s->pipe->conn->event_ctx,
 360                                                   lp_ctx);
 361         if (composite_nomem(epm_map_req, c)) return c;
 362
 363         composite_continue(c, epm_map_req, continue_epm_map_binding, c);
 364         return c;
 365 }
 366
 367
 368 /*
 369   Receive result of schannel key request
 370  */
 371 NTSTATUS dcerpc_schannel_key_recv(struct composite_context *c)
 372 {
 373         NTSTATUS status = composite_wait(c);
 374
 375         talloc_free(c);
 376         return status;
 377 }
 378
 379
 380 struct auth_schannel_state {
 381         struct dcerpc_pipe *pipe;
 382         struct cli_credentials *credentials;
 383         const struct ndr_interface_table *table;
 384         struct loadparm_context *lp_ctx;
 385         uint8_t auth_level;
 386 };
 387
 388
 389 static void continue_bind_auth(struct composite_context *ctx);
 390
 391
 392 /*
 393   Stage 2 of auth_schannel: Receive schannel key and intitiate an
 394   authenticated bind using received credentials
 395  */
 396 static void continue_schannel_key(struct composite_context *ctx)
 397 {
 398         struct composite_context *auth_req;
 399         struct composite_context *c = talloc_get_type(ctx->async.private_data,
 400                                                       struct composite_context);
 401         struct auth_schannel_state *s = talloc_get_type(c->private_data,
 402                                                         struct auth_schannel_state);
 403         NTSTATUS status;
 404
 405         /* receive schannel key */
 406         status = c->status = dcerpc_schannel_key_recv(ctx);
 407         if (!composite_is_ok(c)) {
 408                 DEBUG(1, ("Failed to setup credentials: %s\n", nt_errstr(status)));
 409                 return;
 410         }
 411
 412         /* send bind auth request with received creds */
 413         auth_req = dcerpc_bind_auth_send(c, s->pipe, s->table, s->credentials,
 414                                          lpcfg_gensec_settings(c, s->lp_ctx),
 415                                          DCERPC_AUTH_TYPE_SCHANNEL, s->auth_level,
 416                                          NULL);
 417         if (composite_nomem(auth_req, c)) return;
 418
 419         composite_continue(c, auth_req, continue_bind_auth, c);
 420 }
 421
 422
 423 /*
 424   Stage 3 of auth_schannel: Receivce result of authenticated bind
 425   and say if we're done ok.
 426 */
 427 static void continue_bind_auth(struct composite_context *ctx)
 428 {
 429         struct composite_context *c = talloc_get_type(ctx->async.private_data,
 430                                                       struct composite_context);
 431
 432         c->status = dcerpc_bind_auth_recv(ctx);
 433         if (!composite_is_ok(c)) return;
 434
 435         composite_done(c);
 436 }
 437
 438
 439 /*
 440   Initiate schannel authentication request
 441 */
 442 struct composite_context *dcerpc_bind_auth_schannel_send(TALLOC_CTX *tmp_ctx,
 443                                                          struct dcerpc_pipe *p,
 444                                                          const struct ndr_interface_table *table,
 445                                                          struct cli_credentials *credentials,
 446                                                          struct loadparm_context *lp_ctx,
 447                                                          uint8_t auth_level)
 448 {
 449         struct composite_context *c;
 450         struct auth_schannel_state *s;
 451         struct composite_context *schan_key_req;
 452
 453         /* composite context allocation and setup */
 454         c = composite_create(tmp_ctx, p->conn->event_ctx);
 455         if (c == NULL) return NULL;
 456
 457         s = talloc_zero(c, struct auth_schannel_state);
 458         if (composite_nomem(s, c)) return c;
 459         c->private_data = s;
 460
 461         /* store parameters in the state structure */
 462         s->pipe        = p;
 463         s->credentials = credentials;
 464         s->table       = table;
 465         s->auth_level  = auth_level;
 466         s->lp_ctx      = lp_ctx;
 467
 468         /* start getting schannel key first */
 469         schan_key_req = dcerpc_schannel_key_send(c, p, credentials, lp_ctx);
 470         if (composite_nomem(schan_key_req, c)) return c;
 471
 472         composite_continue(c, schan_key_req, continue_schannel_key, c);
 473         return c;
 474 }
 475
 476
 477 /*
 478   Receive result of schannel authentication request
 479 */
 480 NTSTATUS dcerpc_bind_auth_schannel_recv(struct composite_context *c)
 481 {
 482         NTSTATUS status = composite_wait(c);
 483
 484         talloc_free(c);
 485         return status;
 486 }
 487
 488
 489 /*
 490   Perform schannel authenticated bind - sync version
 491  */
 492 _PUBLIC_ NTSTATUS dcerpc_bind_auth_schannel(TALLOC_CTX *tmp_ctx,
 493                                    struct dcerpc_pipe *p,
 494                                    const struct ndr_interface_table *table,
 495                                    struct cli_credentials *credentials,
 496                                    struct loadparm_context *lp_ctx,
 497                                    uint8_t auth_level)
 498 {
 499         struct composite_context *c;
 500
 501         c = dcerpc_bind_auth_schannel_send(tmp_ctx, p, table, credentials, lp_ctx,
 502                                            auth_level);
 503         return dcerpc_bind_auth_schannel_recv(c);
 504 }