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
  25 enum schannel_position {
  26         DCERPC_SCHANNEL_STATE_START = 0,
  27         DCERPC_SCHANNEL_STATE_UPDATE_1
  28 };
  29
  30 struct dcerpc_schannel_state {
  31         TALLOC_CTX *mem_ctx;
  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->mem_ctx, 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
 187                 bind_schannel_ack.unknown1 = 1;
 188                 bind_schannel_ack.unknown2 = 0;
 189                 bind_schannel_ack.unknown3 = 0x6c0000;
 190
 191                 status = ndr_push_struct_blob(out, out_mem_ctx, &bind_schannel_ack,
 192                                               (ndr_push_flags_fn_t)ndr_push_schannel_bind_ack);
 193                 if (!NT_STATUS_IS_OK(status)) {
 194                         DEBUG(3, ("Could not return schannel bind ack for account %s: %s\n",
 195                                   account_name, nt_errstr(status)));
 196                         return status;
 197                 }
 198
 199                 dce_schan_state->state = DCERPC_SCHANNEL_STATE_UPDATE_1;
 200
 201                 return NT_STATUS_OK;
 202         }
 203         return NT_STATUS_INVALID_PARAMETER;
 204 }
 205
 206 /**
 207  * Return the credentials of a logged on user, including session keys
 208  * etc.
 209  *
 210  * Only valid after a successful authentication
 211  *
 212  * May only be called once per authentication.
 213  *
 214  */
 215
 216 NTSTATUS dcerpc_schannel_session_info(struct gensec_security *gensec_security,
 217                                       struct auth_session_info **session_info)
 218 {
 219         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
 220
 221         (*session_info) = talloc_p(gensec_security, struct auth_session_info);
 222         if (*session_info == NULL) {
 223                 return NT_STATUS_NO_MEMORY;
 224         }
 225
 226         ZERO_STRUCTP(*session_info);
 227         (*session_info)->refcount = 1;
 228
 229         (*session_info)->workstation = talloc_strdup(*session_info, dce_schan_state->account_name);
 230         if ((*session_info)->workstation == NULL) {
 231                 talloc_free(*session_info);
 232                 return NT_STATUS_NO_MEMORY;
 233         }
 234         return NT_STATUS_OK;
 235 }
 236
 237
 238 /**
 239  * Return the struct creds_CredentialState.
 240  *
 241  * Make sure not to call this unless gensec is using schannel...
 242  */
 243
 244 NTSTATUS dcerpc_schannel_creds(struct gensec_security *gensec_security,
 245                                TALLOC_CTX *mem_ctx,
 246                                struct creds_CredentialState **creds)
 247 {
 248         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
 249
 250         *creds = talloc_p(mem_ctx, struct creds_CredentialState);
 251         if (!*creds) {
 252                 return NT_STATUS_NO_MEMORY;
 253         }
 254
 255         **creds = dce_schan_state->creds;
 256         return NT_STATUS_OK;
 257 }
 258
 259
 260 static NTSTATUS dcerpc_schannel_start(struct gensec_security *gensec_security)
 261 {
 262         struct dcerpc_schannel_state *dce_schan_state;
 263         TALLOC_CTX *mem_ctx;
 264         mem_ctx = talloc_init("dcerpc_schannel_start");
 265         if (!mem_ctx) {
 266                 return NT_STATUS_NO_MEMORY;
 267         }
 268
 269         dce_schan_state = talloc_p(mem_ctx, struct dcerpc_schannel_state);
 270         if (!dce_schan_state) {
 271                 talloc_destroy(mem_ctx);
 272                 return NT_STATUS_NO_MEMORY;
 273         }
 274
 275         dce_schan_state->mem_ctx = mem_ctx;
 276         dce_schan_state->state = DCERPC_SCHANNEL_STATE_START;
 277
 278
 279         gensec_security->private_data = dce_schan_state;
 280
 281         return NT_STATUS_OK;
 282 }
 283
 284 static NTSTATUS dcerpc_schannel_server_start(struct gensec_security *gensec_security)
 285 {
 286         NTSTATUS status;
 287         struct dcerpc_schannel_state *dce_schan_state;
 288
 289         status = dcerpc_schannel_start(gensec_security);
 290
 291         dce_schan_state = gensec_security->private_data;
 292         dce_schan_state->schannel_state = NULL;
 293
 294         if (!NT_STATUS_IS_OK(status)) {
 295                 return status;
 296         }
 297         return NT_STATUS_OK;
 298 }
 299
 300 static NTSTATUS dcerpc_schannel_client_start(struct gensec_security *gensec_security)
 301 {
 302         NTSTATUS status;
 303         struct dcerpc_schannel_state *dce_schan_state;
 304
 305         status = dcerpc_schannel_start(gensec_security);
 306         if (!NT_STATUS_IS_OK(status)) {
 307                 return status;
 308         }
 309         dce_schan_state = gensec_security->private_data;
 310
 311         status = schannel_start(&dce_schan_state->schannel_state,
 312                                 gensec_security->user.schan_session_key,
 313                                 True);
 314         if (!NT_STATUS_IS_OK(status)) {
 315                 DEBUG(1, ("Failed to start schannel client\n"));
 316                 return status;
 317         }
 318
 319         return NT_STATUS_OK;
 320 }
 321
 322 /*
 323   end crypto state
 324 */
 325 static void dcerpc_schannel_end(struct gensec_security *gensec_security)
 326 {
 327         struct dcerpc_schannel_state *dce_schan_state = gensec_security->private_data;
 328
 329         schannel_end(&dce_schan_state->schannel_state);
 330
 331         talloc_destroy(dce_schan_state->mem_ctx);
 332
 333         gensec_security->private_data = NULL;
 334 }
 335
 336
 337 /*
 338   get a schannel key using a netlogon challenge on a secondary pipe
 339 */
 340 static NTSTATUS dcerpc_schannel_key(struct dcerpc_pipe *p,
 341                                     const char *domain,
 342                                     const char *username,
 343                                     const char *password,
 344                                     int chan_type,
 345                                     uint8_t new_session_key[16])
 346 {
 347         NTSTATUS status;
 348         struct dcerpc_pipe *p2;
 349         struct netr_ServerReqChallenge r;
 350         struct netr_ServerAuthenticate2 a;
 351         struct netr_Credential credentials1, credentials2, credentials3;
 352         struct samr_Password mach_pwd;
 353         struct creds_CredentialState creds;
 354         const char *workgroup, *workstation;
 355         uint32_t negotiate_flags;
 356
 357         if (p->flags & DCERPC_SCHANNEL_128) {
 358                 negotiate_flags = NETLOGON_NEG_AUTH2_ADS_FLAGS;
 359         } else {
 360                 negotiate_flags = NETLOGON_NEG_AUTH2_FLAGS;
 361         }
 362
 363         workstation = username;
 364         workgroup = domain;
 365
 366         /*
 367           step 1 - establish a netlogon connection, with no authentication
 368         */
 369         status = dcerpc_secondary_connection(p, &p2,
 370                                              DCERPC_NETLOGON_NAME,
 371                                              DCERPC_NETLOGON_UUID,
 372                                              DCERPC_NETLOGON_VERSION);
 373
 374
 375         /*
 376           step 2 - request a netlogon challenge
 377         */
 378         r.in.server_name = talloc_asprintf(p, "\\\\%s", dcerpc_server_name(p));
 379         r.in.computer_name = workstation;
 380         r.in.credentials = &credentials1;
 381         r.out.credentials = &credentials2;
 382
 383         generate_random_buffer(credentials1.data, sizeof(credentials1.data));
 384
 385         status = dcerpc_netr_ServerReqChallenge(p2, p, &r);
 386         if (!NT_STATUS_IS_OK(status)) {
 387                 return status;
 388         }
 389
 390         /*
 391           step 3 - authenticate on the netlogon pipe
 392         */
 393         E_md4hash(password, mach_pwd.hash);
 394         creds_client_init(&creds, &credentials1, &credentials2, &mach_pwd, &credentials3,
 395                           negotiate_flags);
 396
 397         a.in.server_name = r.in.server_name;
 398         a.in.account_name = talloc_asprintf(p, "%s$", workstation);
 399         a.in.secure_channel_type = chan_type;
 400         a.in.computer_name = workstation;
 401         a.in.negotiate_flags = &negotiate_flags;
 402         a.out.negotiate_flags = &negotiate_flags;
 403         a.in.credentials = &credentials3;
 404         a.out.credentials = &credentials3;
 405
 406         status = dcerpc_netr_ServerAuthenticate2(p2, p, &a);
 407         if (!NT_STATUS_IS_OK(status)) {
 408                 return status;
 409         }
 410
 411         if (!creds_client_check(&creds, a.out.credentials)) {
 412                 return NT_STATUS_UNSUCCESSFUL;
 413         }
 414
 415         /*
 416           the schannel session key is now in creds.session_key
 417
 418           we no longer need the netlogon pipe open
 419         */
 420         dcerpc_pipe_close(p2);
 421
 422         memcpy(new_session_key, creds.session_key, 16);
 423
 424         return NT_STATUS_OK;
 425 }
 426
 427 /*
 428   do a schannel style bind on a dcerpc pipe. The username is usually
 429   of the form HOSTNAME$ and the password is the domain trust password
 430 */
 431 NTSTATUS dcerpc_bind_auth_schannel(struct dcerpc_pipe *p,
 432                                    const char *uuid, uint_t version,
 433                                    const char *domain,
 434                                    const char *username,
 435                                    const char *password)
 436 {
 437         NTSTATUS status;
 438         int chan_type = 0;
 439
 440         status = gensec_client_start(p, &p->security_state.generic_state);
 441         if (!NT_STATUS_IS_OK(status)) {
 442                 return status;
 443         }
 444
 445         if (p->flags & DCERPC_SCHANNEL_BDC) {
 446                 chan_type = SEC_CHAN_BDC;
 447         } else if (p->flags & DCERPC_SCHANNEL_WORKSTATION) {
 448                 chan_type = SEC_CHAN_WKSTA;
 449         } else if (p->flags & DCERPC_SCHANNEL_DOMAIN) {
 450                 chan_type = SEC_CHAN_DOMAIN;
 451         }
 452
 453         status = dcerpc_schannel_key(p, domain,
 454                                      username,
 455                                      password,
 456                                      chan_type,
 457                                      p->security_state.generic_state->user.schan_session_key);
 458         if (!NT_STATUS_IS_OK(status)) {
 459                 DEBUG(1, ("Failed to fetch schannel session key: %s\n", nt_errstr(status)));
 460                 gensec_end(&p->security_state.generic_state);
 461                 return status;
 462         }
 463
 464         status = gensec_set_username(p->security_state.generic_state, username);
 465         if (!NT_STATUS_IS_OK(status)) {
 466                 DEBUG(1, ("Failed to set schannel username to %s: %s\n", username, nt_errstr(status)));
 467                 gensec_end(&p->security_state.generic_state);
 468                 return status;
 469         }
 470
 471         status = gensec_set_domain(p->security_state.generic_state, domain);
 472         if (!NT_STATUS_IS_OK(status)) {
 473                 DEBUG(1, ("Failed to set schannel domain to %s: %s\n", domain, nt_errstr(status)));
 474                 gensec_end(&p->security_state.generic_state);
 475                 return status;
 476         }
 477
 478         status = gensec_start_mech_by_authtype(p->security_state.generic_state, DCERPC_AUTH_TYPE_SCHANNEL, dcerpc_auth_level(p));
 479
 480         if (!NT_STATUS_IS_OK(status)) {
 481                 DEBUG(1, ("Failed to start SCHANNEL GENSEC backend: %s\n", nt_errstr(status)));
 482                 gensec_end(&p->security_state.generic_state);
 483                 return status;
 484         }
 485
 486         status = dcerpc_bind_auth3(p, DCERPC_AUTH_TYPE_SCHANNEL, dcerpc_auth_level(p),
 487                                   uuid, version);
 488
 489         if (!NT_STATUS_IS_OK(status)) {
 490                 DEBUG(1, ("Failed to bind to pipe with SCHANNEL: %s\n", nt_errstr(status)));
 491                 gensec_end(&p->security_state.generic_state);
 492                 return status;
 493         }
 494
 495         return NT_STATUS_OK;
 496 }
 497
 498
 499 static const struct gensec_security_ops gensec_dcerpc_schannel_security_ops = {
 500         .name           = "dcerpc_schannel",
 501         .auth_type      = DCERPC_AUTH_TYPE_SCHANNEL,
 502         .client_start   = dcerpc_schannel_client_start,
 503         .server_start   = dcerpc_schannel_server_start,
 504         .update         = dcerpc_schannel_update,
 505         .seal_packet    = dcerpc_schannel_seal_packet,
 506         .sign_packet    = dcerpc_schannel_sign_packet,
 507         .check_packet   = dcerpc_schannel_check_packet,
 508         .unseal_packet  = dcerpc_schannel_unseal_packet,
 509         .session_key    = dcerpc_schannel_session_key,
 510         .session_info   = dcerpc_schannel_session_info,
 511         .sig_size       = dcerpc_schannel_sig_size,
 512         .end            = dcerpc_schannel_end
 513 };
 514
 515 NTSTATUS gensec_dcerpc_schannel_init(void)
 516 {
 517         NTSTATUS ret;
 518         ret = register_backend("gensec", &gensec_dcerpc_schannel_security_ops);
 519         if (!NT_STATUS_IS_OK(ret)) {
 520                 DEBUG(0,("Failed to register '%s' gensec backend!\n",
 521                         gensec_dcerpc_schannel_security_ops.name));
 522                 return ret;
 523         }
 524
 525         return ret;
 526 }