source/librpc/rpc/dcerpc_schannel.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    dcerpc schannel operations
   5
   6    Copyright (C) Andrew Tridgell 2004
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  21 */
  22
  23 #include "includes.h"
  24 #include "librpc/gen_ndr/ndr_schannel.h"
  25 #include "auth/auth.h"
  26
  27 enum schannel_position {
  28         DCERPC_SCHANNEL_STATE_START = 0,
  29         DCERPC_SCHANNEL_STATE_UPDATE_1
  30 };
  31
  32 struct dcerpc_schannel_state {
  33         enum schannel_position state;
  34         struct schannel_state *schannel_state;
  35         struct creds_CredentialState creds;
  36         char *account_name;
  37 };
  38
  39 static NTSTATUS dcerpc_schannel_key(struct dcerpc_pipe *p,
  40                                     const char *domain,
  41                                     const char *username,
  42                                     const char *password,
  43                                     int chan_type,
  44                                     uint8_t new_session_key[16]);
  45
  46 /*
  47   wrappers for the schannel_*() functions
  48
  49   These will become static again, when we get dynamic registration, and
  50   decrpc_schannel_security_ops come back here.
  51 */
  52 static NTSTATUS dcerpc_schannel_unseal_packet(struct gensec_security *gensec_security,
  53                                               TALLOC_CTX *mem_ctx,
  54                                               uint8_t *data, size_t length,
  55                                               const uint8_t *whole_pdu, size_t pdu_length,
  56                                               DATA_BLOB *sig)
  57 {
  58         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
  59
  60         return schannel_unseal_packet(dce_schan_state->schannel_state, mem_ctx, data, length, sig);
  61 }
  62
  63 static NTSTATUS dcerpc_schannel_check_packet(struct gensec_security *gensec_security,
  64                                              TALLOC_CTX *mem_ctx,
  65                                              const uint8_t *data, size_t length,
  66                                              const uint8_t *whole_pdu, size_t pdu_length,
  67                                              const DATA_BLOB *sig)
  68 {
  69         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
  70
  71         return schannel_check_packet(dce_schan_state->schannel_state, data, length, sig);
  72 }
  73
  74 static NTSTATUS dcerpc_schannel_seal_packet(struct gensec_security *gensec_security,
  75                                             TALLOC_CTX *mem_ctx,
  76                                             uint8_t *data, size_t length,
  77                                             const uint8_t *whole_pdu, size_t pdu_length,
  78                                             DATA_BLOB *sig)
  79 {
  80         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
  81
  82         return schannel_seal_packet(dce_schan_state->schannel_state, mem_ctx, data, length, sig);
  83 }
  84
  85 static NTSTATUS dcerpc_schannel_sign_packet(struct gensec_security *gensec_security,
  86                                             TALLOC_CTX *mem_ctx,
  87                                             const uint8_t *data, size_t length,
  88                                             const uint8_t *whole_pdu, size_t pdu_length,
  89                                             DATA_BLOB *sig)
  90 {
  91         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
  92
  93         return schannel_sign_packet(dce_schan_state->schannel_state, mem_ctx, data, length, sig);
  94 }
  95
  96 static size_t dcerpc_schannel_sig_size(struct gensec_security *gensec_security)
  97 {
  98         return 32;
  99 }
 100
 101 static NTSTATUS dcerpc_schannel_session_key(struct gensec_security *gensec_security,
 102                                             DATA_BLOB *session_key)
 103 {
 104         return NT_STATUS_NOT_IMPLEMENTED;
 105 }
 106
 107 static NTSTATUS dcerpc_schannel_update(struct gensec_security *gensec_security, TALLOC_CTX *out_mem_ctx,
 108                                        const DATA_BLOB in, DATA_BLOB *out)
 109 {
 110         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
 111         NTSTATUS status;
 112         struct schannel_bind bind_schannel;
 113         struct schannel_bind_ack bind_schannel_ack;
 114         const char *account_name;
 115         *out = data_blob(NULL, 0);
 116
 117         switch (gensec_security->gensec_role) {
 118         case GENSEC_CLIENT:
 119                 if (dce_schan_state->state != DCERPC_SCHANNEL_STATE_START) {
 120                         /* we could parse the bind ack, but we don't know what it is yet */
 121                         return NT_STATUS_OK;
 122                 }
 123
 124                 bind_schannel.unknown1 = 0;
 125 #if 0
 126                 /* to support this we'd need to have access to the full domain name */
 127                 bind_schannel.bind_type = 23;
 128                 bind_schannel.u.info23.domain = gensec_security->user.domain;
 129                 bind_schannel.u.info23.account_name = gensec_security->user.name;
 130                 bind_schannel.u.info23.dnsdomain = str_format_nbt_domain(out_mem_ctx, fulldomainname);
 131                 bind_schannel.u.info23.workstation = str_format_nbt_domain(out_mem_ctx, gensec_security->user.name);
 132 #else
 133                 bind_schannel.bind_type = 3;
 134                 bind_schannel.u.info3.domain = gensec_security->user.domain;
 135                 bind_schannel.u.info3.account_name = gensec_security->user.name;
 136 #endif
 137
 138                 status = ndr_push_struct_blob(out, out_mem_ctx, &bind_schannel,
 139                                               (ndr_push_flags_fn_t)ndr_push_schannel_bind);
 140                 if (!NT_STATUS_IS_OK(status)) {
 141                         DEBUG(3, ("Could not create schannel bind: %s\n",
 142                                   nt_errstr(status)));
 143                         return status;
 144                 }
 145
 146                 dce_schan_state->state = DCERPC_SCHANNEL_STATE_UPDATE_1;
 147
 148                 return NT_STATUS_MORE_PROCESSING_REQUIRED;
 149         case GENSEC_SERVER:
 150
 151                 if (dce_schan_state->state != DCERPC_SCHANNEL_STATE_START) {
 152                         /* no third leg on this protocol */
 153                         return NT_STATUS_INVALID_PARAMETER;
 154                 }
 155
 156                 /* parse the schannel startup blob */
 157                 status = ndr_pull_struct_blob(&in, out_mem_ctx, &bind_schannel,
 158                                               (ndr_pull_flags_fn_t)ndr_pull_schannel_bind);
 159                 if (!NT_STATUS_IS_OK(status)) {
 160                         return status;
 161                 }
 162
 163                 if (bind_schannel.bind_type == 23) {
 164                         account_name = bind_schannel.u.info23.account_name;
 165                 } else {
 166                         account_name = bind_schannel.u.info3.account_name;
 167                 }
 168
 169                 /* pull the session key for this client */
 170                 status = schannel_fetch_session_key(out_mem_ctx, account_name, &dce_schan_state->creds);
 171                 if (!NT_STATUS_IS_OK(status)) {
 172                         DEBUG(3, ("Could not find session key for attempted schannel connection on %s: %s\n",
 173                                   account_name, nt_errstr(status)));
 174                         return status;
 175                 }
 176
 177                 dce_schan_state->account_name = talloc_strdup(dce_schan_state, account_name);
 178
 179                 /* start up the schannel server code */
 180                 status = schannel_start(&dce_schan_state->schannel_state,
 181                                         dce_schan_state->creds.session_key, False);
 182                 if (!NT_STATUS_IS_OK(status)) {
 183                         DEBUG(3, ("Could not initialise schannel state for account %s: %s\n",
 184                                   account_name, nt_errstr(status)));
 185                         return status;
 186                 }
 187                 talloc_steal(dce_schan_state, dce_schan_state->schannel_state);
 188
 189                 bind_schannel_ack.unknown1 = 1;
 190                 bind_schannel_ack.unknown2 = 0;
 191                 bind_schannel_ack.unknown3 = 0x6c0000;
 192
 193                 status = ndr_push_struct_blob(out, out_mem_ctx, &bind_schannel_ack,
 194                                               (ndr_push_flags_fn_t)ndr_push_schannel_bind_ack);
 195                 if (!NT_STATUS_IS_OK(status)) {
 196                         DEBUG(3, ("Could not return schannel bind ack for account %s: %s\n",
 197                                   account_name, nt_errstr(status)));
 198                         return status;
 199                 }
 200
 201                 dce_schan_state->state = DCERPC_SCHANNEL_STATE_UPDATE_1;
 202
 203                 return NT_STATUS_OK;
 204         }
 205         return NT_STATUS_INVALID_PARAMETER;
 206 }
 207
 208 /**
 209  * Return the credentials of a logged on user, including session keys
 210  * etc.
 211  *
 212  * Only valid after a successful authentication
 213  *
 214  * May only be called once per authentication.
 215  *
 216  */
 217
 218 NTSTATUS dcerpc_schannel_session_info(struct gensec_security *gensec_security,
 219                                       struct auth_session_info **session_info)
 220 {
 221         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
 222
 223         (*session_info) = talloc_p(gensec_security, struct auth_session_info);
 224         if (*session_info == NULL) {
 225                 return NT_STATUS_NO_MEMORY;
 226         }
 227
 228         ZERO_STRUCTP(*session_info);
 229         (*session_info)->refcount = 1;
 230
 231         (*session_info)->workstation = talloc_strdup(*session_info, dce_schan_state->account_name);
 232         if ((*session_info)->workstation == NULL) {
 233                 talloc_free(*session_info);
 234                 return NT_STATUS_NO_MEMORY;
 235         }
 236         return NT_STATUS_OK;
 237 }
 238
 239
 240 /**
 241  * Return the struct creds_CredentialState.
 242  *
 243  * Make sure not to call this unless gensec is using schannel...
 244  */
 245
 246 NTSTATUS dcerpc_schannel_creds(struct gensec_security *gensec_security,
 247                                TALLOC_CTX *mem_ctx,
 248                                struct creds_CredentialState **creds)
 249 {
 250         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
 251
 252         *creds = talloc_p(mem_ctx, struct creds_CredentialState);
 253         if (!*creds) {
 254                 return NT_STATUS_NO_MEMORY;
 255         }
 256
 257         **creds = dce_schan_state->creds;
 258         return NT_STATUS_OK;
 259 }
 260
 261
 262 static NTSTATUS dcerpc_schannel_start(struct gensec_security *gensec_security)
 263 {
 264         struct dcerpc_schannel_state *dce_schan_state;
 265
 266         dce_schan_state = talloc_p(gensec_security, struct dcerpc_schannel_state);
 267         if (!dce_schan_state) {
 268                 return NT_STATUS_NO_MEMORY;
 269         }
 270
 271         dce_schan_state->state = DCERPC_SCHANNEL_STATE_START;
 272         gensec_security->private_data = dce_schan_state;
 273
 274         return NT_STATUS_OK;
 275 }
 276
 277 static NTSTATUS dcerpc_schannel_server_start(struct gensec_security *gensec_security)
 278 {
 279         NTSTATUS status;
 280         struct dcerpc_schannel_state *dce_schan_state;
 281
 282         status = dcerpc_schannel_start(gensec_security);
 283
 284         dce_schan_state = gensec_security->private_data;
 285         dce_schan_state->schannel_state = NULL;
 286
 287         if (!NT_STATUS_IS_OK(status)) {
 288                 return status;
 289         }
 290         return NT_STATUS_OK;
 291 }
 292
 293 static NTSTATUS dcerpc_schannel_client_start(struct gensec_security *gensec_security)
 294 {
 295         NTSTATUS status;
 296         struct dcerpc_schannel_state *dce_schan_state;
 297
 298         status = dcerpc_schannel_start(gensec_security);
 299         if (!NT_STATUS_IS_OK(status)) {
 300                 return status;
 301         }
 302         dce_schan_state = gensec_security->private_data;
 303
 304         status = schannel_start(&dce_schan_state->schannel_state,
 305                                 gensec_security->user.schan_session_key,
 306                                 True);
 307         if (!NT_STATUS_IS_OK(status)) {
 308                 DEBUG(1, ("Failed to start schannel client\n"));
 309                 return status;
 310         }
 311         talloc_steal(dce_schan_state, dce_schan_state->schannel_state);
 312
 313         return NT_STATUS_OK;
 314 }
 315
 316 /*
 317   end crypto state
 318 */
 319 static void dcerpc_schannel_end(struct gensec_security *gensec_security)
 320 {
 321         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
 322
 323         schannel_end(&dce_schan_state->schannel_state);
 324
 325         talloc_free(dce_schan_state);
 326
 327         gensec_security->private_data = NULL;
 328 }
 329
 330
 331 /*
 332   get a schannel key using a netlogon challenge on a secondary pipe
 333 */
 334 static NTSTATUS dcerpc_schannel_key(struct dcerpc_pipe *p,
 335                                     const char *domain,
 336                                     const char *username,
 337                                     const char *password,
 338                                     int chan_type,
 339                                     uint8_t new_session_key[16])
 340 {
 341         NTSTATUS status;
 342         struct dcerpc_pipe *p2;
 343         struct netr_ServerReqChallenge r;
 344         struct netr_ServerAuthenticate2 a;
 345         struct netr_Credential credentials1, credentials2, credentials3;
 346         struct samr_Password mach_pwd;
 347         struct creds_CredentialState creds;
 348         const char *workgroup, *workstation;
 349         uint32_t negotiate_flags;
 350
 351         if (p->flags & DCERPC_SCHANNEL_128) {
 352                 negotiate_flags = NETLOGON_NEG_AUTH2_ADS_FLAGS;
 353         } else {
 354                 negotiate_flags = NETLOGON_NEG_AUTH2_FLAGS;
 355         }
 356
 357         workstation = username;
 358         workgroup = domain;
 359
 360         /*
 361           step 1 - establish a netlogon connection, with no authentication
 362         */
 363         status = dcerpc_secondary_connection(p, &p2,
 364                                              DCERPC_NETLOGON_NAME,
 365                                              DCERPC_NETLOGON_UUID,
 366                                              DCERPC_NETLOGON_VERSION);
 367         if (!NT_STATUS_IS_OK(status)) {
 368                 return status;
 369         }
 370
 371
 372         /*
 373           step 2 - request a netlogon challenge
 374         */
 375         r.in.server_name = talloc_asprintf(p, "\\\\%s", dcerpc_server_name(p));
 376         r.in.computer_name = workstation;
 377         r.in.credentials = &credentials1;
 378         r.out.credentials = &credentials2;
 379
 380         generate_random_buffer(credentials1.data, sizeof(credentials1.data));
 381
 382         status = dcerpc_netr_ServerReqChallenge(p2, p, &r);
 383         if (!NT_STATUS_IS_OK(status)) {
 384                 return status;
 385         }
 386
 387         /*
 388           step 3 - authenticate on the netlogon pipe
 389         */
 390         E_md4hash(password, mach_pwd.hash);
 391         creds_client_init(&creds, &credentials1, &credentials2, &mach_pwd, &credentials3,
 392                           negotiate_flags);
 393
 394         a.in.server_name = r.in.server_name;
 395         a.in.account_name = talloc_asprintf(p, "%s$", workstation);
 396         a.in.secure_channel_type = chan_type;
 397         a.in.computer_name = workstation;
 398         a.in.negotiate_flags = &negotiate_flags;
 399         a.out.negotiate_flags = &negotiate_flags;
 400         a.in.credentials = &credentials3;
 401         a.out.credentials = &credentials3;
 402
 403         status = dcerpc_netr_ServerAuthenticate2(p2, p, &a);
 404         if (!NT_STATUS_IS_OK(status)) {
 405                 return status;
 406         }
 407
 408         if (!creds_client_check(&creds, a.out.credentials)) {
 409                 return NT_STATUS_UNSUCCESSFUL;
 410         }
 411
 412         /*
 413           the schannel session key is now in creds.session_key
 414
 415           we no longer need the netlogon pipe open
 416         */
 417         dcerpc_pipe_close(p2);
 418
 419         memcpy(new_session_key, creds.session_key, 16);
 420
 421         return NT_STATUS_OK;
 422 }
 423
 424 /*
 425   do a schannel style bind on a dcerpc pipe. The username is usually
 426   of the form HOSTNAME$ and the password is the domain trust password
 427 */
 428 NTSTATUS dcerpc_bind_auth_schannel_withkey(struct dcerpc_pipe *p,
 429                                            const char *uuid, uint_t version,
 430                                            const char *domain,
 431                                            const char *username,
 432                                            const char *password,
 433                                            uint8_t session_key[16])
 434 {
 435         NTSTATUS status;
 436
 437         status = gensec_client_start(p, &p->security_state.generic_state);
 438         if (!NT_STATUS_IS_OK(status)) {
 439                 return status;
 440         }
 441
 442         memcpy(p->security_state.generic_state->user.schan_session_key,
 443                session_key, 16);
 444
 445         status = gensec_set_username(p->security_state.generic_state, username);
 446         if (!NT_STATUS_IS_OK(status)) {
 447                 DEBUG(1, ("Failed to set schannel username to %s: %s\n", username, nt_errstr(status)));
 448                 gensec_end(&p->security_state.generic_state);
 449                 return status;
 450         }
 451
 452         status = gensec_set_domain(p->security_state.generic_state, domain);
 453         if (!NT_STATUS_IS_OK(status)) {
 454                 DEBUG(1, ("Failed to set schannel domain to %s: %s\n", domain, nt_errstr(status)));
 455                 gensec_end(&p->security_state.generic_state);
 456                 return status;
 457         }
 458
 459         status = gensec_start_mech_by_authtype(p->security_state.generic_state, DCERPC_AUTH_TYPE_SCHANNEL, dcerpc_auth_level(p));
 460
 461         if (!NT_STATUS_IS_OK(status)) {
 462                 DEBUG(1, ("Failed to start SCHANNEL GENSEC backend: %s\n", nt_errstr(status)));
 463                 gensec_end(&p->security_state.generic_state);
 464                 return status;
 465         }
 466
 467         status = dcerpc_bind_auth3(p, DCERPC_AUTH_TYPE_SCHANNEL, dcerpc_auth_level(p),
 468                                   uuid, version);
 469
 470         if (!NT_STATUS_IS_OK(status)) {
 471                 DEBUG(1, ("Failed to bind to pipe with SCHANNEL: %s\n", nt_errstr(status)));
 472                 gensec_end(&p->security_state.generic_state);
 473                 return status;
 474         }
 475
 476         return NT_STATUS_OK;
 477 }
 478
 479 NTSTATUS dcerpc_bind_auth_schannel(struct dcerpc_pipe *p,
 480                                    const char *uuid, uint_t version,
 481                                    const char *domain,
 482                                    const char *username,
 483                                    const char *password)
 484 {
 485         NTSTATUS status;
 486         int chan_type = 0;
 487         uint8_t new_session_key[16];
 488
 489         if (p->flags & DCERPC_SCHANNEL_BDC) {
 490                 chan_type = SEC_CHAN_BDC;
 491         } else if (p->flags & DCERPC_SCHANNEL_WORKSTATION) {
 492                 chan_type = SEC_CHAN_WKSTA;
 493         } else if (p->flags & DCERPC_SCHANNEL_DOMAIN) {
 494                 chan_type = SEC_CHAN_DOMAIN;
 495         }
 496
 497         status = dcerpc_schannel_key(p, domain,
 498                                      username,
 499                                      password,
 500                                      chan_type,
 501                                      new_session_key);
 502
 503         if (!NT_STATUS_IS_OK(status)) {
 504                 DEBUG(1, ("Failed to fetch schannel session key: %s\n",
 505                           nt_errstr(status)));
 506                 return status;
 507         }
 508
 509         return dcerpc_bind_auth_schannel_withkey(p, uuid, version, domain,
 510                                                  username, password,
 511                                                  new_session_key);
 512 }
 513
 514 static const struct gensec_security_ops gensec_dcerpc_schannel_security_ops = {
 515         .name           = "dcerpc_schannel",
 516         .auth_type      = DCERPC_AUTH_TYPE_SCHANNEL,
 517         .client_start   = dcerpc_schannel_client_start,
 518         .server_start   = dcerpc_schannel_server_start,
 519         .update         = dcerpc_schannel_update,
 520         .seal_packet    = dcerpc_schannel_seal_packet,
 521         .sign_packet    = dcerpc_schannel_sign_packet,
 522         .check_packet   = dcerpc_schannel_check_packet,
 523         .unseal_packet  = dcerpc_schannel_unseal_packet,
 524         .session_key    = dcerpc_schannel_session_key,
 525         .session_info   = dcerpc_schannel_session_info,
 526         .sig_size       = dcerpc_schannel_sig_size,
 527         .end            = dcerpc_schannel_end
 528 };
 529
 530 NTSTATUS gensec_dcerpc_schannel_init(void)
 531 {
 532         NTSTATUS ret;
 533         ret = register_backend("gensec", &gensec_dcerpc_schannel_security_ops);
 534         if (!NT_STATUS_IS_OK(ret)) {
 535                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 536                         gensec_dcerpc_schannel_security_ops.name));
 537                 return ret;
 538         }
 539
 540         return ret;
 541 }