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