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