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