source4/kdc/kdc-heimdal.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    KDC Server startup
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2008
   7    Copyright (C) Andrew Tridgell        2005
   8    Copyright (C) Stefan Metzmacher      2005
   9
  10    This program is free software; you can redistribute it and/or modify
  11    it under the terms of the GNU General Public License as published by
  12    the Free Software Foundation; either version 3 of the License, or
  13    (at your option) any later version.
  14
  15    This program is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18    GNU General Public License for more details.
  19
  20    You should have received a copy of the GNU General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "includes.h"
  25 #include "samba/process_model.h"
  26 #include "lib/tsocket/tsocket.h"
  27 #include "lib/messaging/irpc.h"
  28 #include "librpc/gen_ndr/ndr_irpc.h"
  29 #include "librpc/gen_ndr/ndr_krb5pac.h"
  30 #include "lib/socket/netif.h"
  31 #include "param/param.h"
  32 #include "kdc/kdc-server.h"
  33 #include "kdc/kdc-proxy.h"
  34 #include "kdc/kdc-glue.h"
  35 #include "kdc/pac-glue.h"
  36 #include "kdc/kpasswd-service.h"
  37 #include "dsdb/samdb/samdb.h"
  38 #include "auth/session.h"
  39 #include "libds/common/roles.h"
  40 #include <kdc.h>
  41 #include <hdb.h>
  42
  43 #undef DBGC_CLASS
  44 #define DBGC_CLASS DBGC_KERBEROS
  45
  46 NTSTATUS server_service_kdc_init(TALLOC_CTX *);
  47
  48 extern struct krb5plugin_kdc_ftable kdc_plugin_table;
  49
  50 /**
  51    Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
  52    calling conventions
  53 */
  54
  55 static kdc_code kdc_process(struct kdc_server *kdc,
  56                             TALLOC_CTX *mem_ctx,
  57                             DATA_BLOB *input,
  58                             DATA_BLOB *reply,
  59                             struct tsocket_address *peer_addr,
  60                             struct tsocket_address *my_addr,
  61                             int datagram_reply)
  62 {
  63         int ret;
  64         char *pa;
  65         struct sockaddr_storage ss;
  66         krb5_data k5_reply;
  67         krb5_kdc_configuration *kdc_config = kdc->private_data;
  68         struct timespec now_timespec = timespec_current();
  69         struct timeval now_timeval = convert_timespec_to_timeval(now_timespec);
  70
  71         krb5_data_zero(&k5_reply);
  72
  73         krb5_kdc_update_time(&now_timeval);
  74
  75         /* This sets the time into the DSDB opaque */
  76         *kdc->base_ctx->current_nttime_ull = full_timespec_to_nt_time(&now_timespec);
  77
  78         ret = tsocket_address_bsd_sockaddr(peer_addr, (struct sockaddr *) &ss,
  79                                 sizeof(struct sockaddr_storage));
  80         if (ret < 0) {
  81                 return KDC_ERROR;
  82         }
  83         pa = tsocket_address_string(peer_addr, mem_ctx);
  84         if (pa == NULL) {
  85                 return KDC_ERROR;
  86         }
  87
  88         DBG_DEBUG("Received KDC packet of length %zu from %s\n",
  89                   input->length, pa);
  90
  91         ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
  92                                             kdc_config,
  93                                             input->data, input->length,
  94                                             &k5_reply,
  95                                             pa,
  96                                             (struct sockaddr *) &ss,
  97                                             datagram_reply);
  98         if (ret == -1) {
  99                 *reply = data_blob(NULL, 0);
 100                 return KDC_ERROR;
 101         }
 102
 103         if (ret == HDB_ERR_NOT_FOUND_HERE) {
 104                 *reply = data_blob(NULL, 0);
 105                 return KDC_PROXY_REQUEST;
 106         }
 107
 108         if (k5_reply.length) {
 109                 *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
 110                 krb5_data_free(&k5_reply);
 111         } else {
 112                 *reply = data_blob(NULL, 0);
 113         }
 114         return KDC_OK;
 115 }
 116
 117 /*
 118   setup our listening sockets on the configured network interfaces
 119 */
 120 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc,
 121                                        struct loadparm_context *lp_ctx,
 122                                        struct interface *ifaces,
 123                                        const struct model_ops *model_ops)
 124 {
 125         int num_interfaces;
 126         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 127         NTSTATUS status;
 128         int i;
 129         uint16_t kdc_port = lpcfg_krb5_port(lp_ctx);
 130         uint16_t kpasswd_port = lpcfg_kpasswd_port(lp_ctx);
 131         bool done_wildcard = false;
 132
 133         num_interfaces = iface_list_count(ifaces);
 134
 135         /* if we are allowing incoming packets from any address, then
 136            we need to bind to the wildcard address */
 137         if (!lpcfg_bind_interfaces_only(lp_ctx)) {
 138                 size_t num_binds = 0;
 139                 char **wcard = iface_list_wildcard(kdc);
 140                 NT_STATUS_HAVE_NO_MEMORY(wcard);
 141                 for (i=0; wcard[i]; i++) {
 142                         if (kdc_port) {
 143                                 status = kdc_add_socket(kdc, model_ops,
 144                                                         "kdc", wcard[i], kdc_port,
 145                                                         kdc_process, false);
 146                                 if (NT_STATUS_IS_OK(status)) {
 147                                         num_binds++;
 148                                 }
 149                         }
 150
 151                         if (kpasswd_port) {
 152                                 status = kdc_add_socket(kdc, model_ops,
 153                                                         "kpasswd", wcard[i], kpasswd_port,
 154                                                         kpasswd_process, false);
 155                                 if (NT_STATUS_IS_OK(status)) {
 156                                         num_binds++;
 157                                 }
 158                         }
 159                 }
 160                 talloc_free(wcard);
 161                 if (num_binds == 0) {
 162                         return NT_STATUS_INVALID_PARAMETER_MIX;
 163                 }
 164                 done_wildcard = true;
 165         }
 166
 167         for (i=0; i<num_interfaces; i++) {
 168                 const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
 169
 170                 if (kdc_port) {
 171                         status = kdc_add_socket(kdc, model_ops,
 172                                                 "kdc", address, kdc_port,
 173                                                 kdc_process, done_wildcard);
 174                         NT_STATUS_NOT_OK_RETURN(status);
 175                 }
 176
 177                 if (kpasswd_port) {
 178                         status = kdc_add_socket(kdc, model_ops,
 179                                                 "kpasswd", address, kpasswd_port,
 180                                                 kpasswd_process, done_wildcard);
 181                         NT_STATUS_NOT_OK_RETURN(status);
 182                 }
 183         }
 184
 185         talloc_free(tmp_ctx);
 186
 187         return NT_STATUS_OK;
 188 }
 189
 190 static NTSTATUS kdc_check_generic_kerberos(struct irpc_message *msg,
 191                                  struct kdc_check_generic_kerberos *r)
 192 {
 193         struct PAC_Validate pac_validate;
 194         DATA_BLOB srv_sig;
 195         struct PAC_SIGNATURE_DATA kdc_sig;
 196         struct kdc_server *kdc = talloc_get_type(msg->private_data, struct kdc_server);
 197         krb5_kdc_configuration *kdc_config =
 198                 (krb5_kdc_configuration *)kdc->private_data;
 199         enum ndr_err_code ndr_err;
 200         int ret;
 201         hdb_entry ent;
 202         krb5_principal principal;
 203
 204
 205         /* There is no reply to this request */
 206         r->out.generic_reply = data_blob(NULL, 0);
 207
 208         ndr_err = ndr_pull_struct_blob(&r->in.generic_request, msg, &pac_validate,
 209                                        (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
 210         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 211                 return NT_STATUS_INVALID_PARAMETER;
 212         }
 213
 214         if (pac_validate.MessageType != NETLOGON_GENERIC_KRB5_PAC_VALIDATE) {
 215                 /* We don't implement any other message types - such as certificate validation - yet */
 216                 return NT_STATUS_INVALID_PARAMETER;
 217         }
 218
 219         if (pac_validate.ChecksumAndSignature.length != (pac_validate.ChecksumLength + pac_validate.SignatureLength)
 220             || pac_validate.ChecksumAndSignature.length < pac_validate.ChecksumLength
 221             || pac_validate.ChecksumAndSignature.length < pac_validate.SignatureLength ) {
 222                 return NT_STATUS_INVALID_PARAMETER;
 223         }
 224
 225         srv_sig = data_blob_const(pac_validate.ChecksumAndSignature.data,
 226                                   pac_validate.ChecksumLength);
 227
 228         ret = krb5_make_principal(kdc->smb_krb5_context->krb5_context, &principal,
 229                                   lpcfg_realm(kdc->task->lp_ctx),
 230                                   "krbtgt", lpcfg_realm(kdc->task->lp_ctx),
 231                                   NULL);
 232
 233         if (ret != 0) {
 234                 return NT_STATUS_NO_MEMORY;
 235         }
 236
 237         ret = kdc_config->db[0]->hdb_fetch_kvno(kdc->smb_krb5_context->krb5_context,
 238                                                  kdc_config->db[0],
 239                                                  principal,
 240                                                  HDB_F_GET_KRBTGT | HDB_F_DECRYPT,
 241                                                  0,
 242                                                  &ent);
 243
 244         if (ret != 0) {
 245                 hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
 246                 krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
 247
 248                 return NT_STATUS_LOGON_FAILURE;
 249         }
 250
 251         kdc_sig.type = pac_validate.SignatureType;
 252         kdc_sig.signature = data_blob_const(&pac_validate.ChecksumAndSignature.data[pac_validate.ChecksumLength],
 253                                             pac_validate.SignatureLength);
 254
 255         ret = kdc_check_pac(kdc->smb_krb5_context->krb5_context, srv_sig, &kdc_sig, &ent);
 256
 257         hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
 258         krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
 259
 260         if (ret != 0) {
 261                 return NT_STATUS_LOGON_FAILURE;
 262         }
 263
 264         return NT_STATUS_OK;
 265 }
 266
 267
 268 /*
 269   startup the kdc task
 270 */
 271 static NTSTATUS kdc_task_init(struct task_server *task)
 272 {
 273         struct kdc_server *kdc;
 274         NTSTATUS status;
 275         struct interface *ifaces;
 276
 277         switch (lpcfg_server_role(task->lp_ctx)) {
 278         case ROLE_STANDALONE:
 279                 task_server_terminate(task, "kdc: no KDC required in standalone configuration", false);
 280                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 281         case ROLE_DOMAIN_MEMBER:
 282                 task_server_terminate(task, "kdc: no KDC required in member server configuration", false);
 283                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 284         case ROLE_DOMAIN_PDC:
 285         case ROLE_DOMAIN_BDC:
 286         case ROLE_IPA_DC:
 287                 task_server_terminate(
 288                     task, "Cannot start KDC as a 'classic Samba' DC", false);
 289                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 290         case ROLE_ACTIVE_DIRECTORY_DC:
 291                 /* Yes, we want a KDC */
 292                 break;
 293         }
 294
 295         load_interface_list(task, task->lp_ctx, &ifaces);
 296
 297         if (iface_list_count(ifaces) == 0) {
 298                 task_server_terminate(task, "kdc: no network interfaces configured", false);
 299                 return NT_STATUS_UNSUCCESSFUL;
 300         }
 301
 302         task_server_set_title(task, "task[kdc]");
 303
 304         kdc = talloc_zero(task, struct kdc_server);
 305         if (kdc == NULL) {
 306                 task_server_terminate(task, "kdc: out of memory", true);
 307                 return NT_STATUS_NO_MEMORY;
 308         }
 309
 310         kdc->task = task;
 311         task->private_data = kdc;
 312
 313         /* start listening on the configured network interfaces */
 314         status = kdc_startup_interfaces(kdc, task->lp_ctx, ifaces,
 315                                         task->model_ops);
 316         if (!NT_STATUS_IS_OK(status)) {
 317                 task_server_terminate(task, "kdc failed to setup interfaces", true);
 318                 return status;
 319         }
 320
 321
 322         return NT_STATUS_OK;
 323 }
 324
 325 /*
 326   initialise the kdc task after a fork
 327 */
 328 static void kdc_post_fork(struct task_server *task, struct process_details *pd)
 329 {
 330         struct kdc_server *kdc;
 331         krb5_kdc_configuration *kdc_config = NULL;
 332         NTSTATUS status;
 333         krb5_error_code ret;
 334         int ldb_ret;
 335
 336         if (task == NULL) {
 337                 task_server_terminate(task, "kdc: Null task", true);
 338                 return;
 339         }
 340         if (task->private_data == NULL) {
 341                 task_server_terminate(task, "kdc: No kdc_server info", true);
 342                 return;
 343         }
 344         kdc = talloc_get_type_abort(task->private_data, struct kdc_server);
 345
 346         kdc->proxy_timeout = lpcfg_parm_int(kdc->task->lp_ctx, NULL, "kdc", "proxy timeout", 5);
 347
 348         initialize_krb5_error_table();
 349
 350         ret = smb_krb5_init_context(kdc, task->lp_ctx, &kdc->smb_krb5_context);
 351         if (ret) {
 352                 DBG_WARNING("kdc_task_init: krb5_init_context failed (%s)\n",
 353                             error_message(ret));
 354                 task_server_terminate(task, "kdc: krb5_init_context failed", true);
 355                 return;
 356         }
 357
 358         krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
 359
 360         ret = krb5_kdc_get_config(kdc->smb_krb5_context->krb5_context,
 361                                   &kdc_config);
 362         if(ret) {
 363                 task_server_terminate(task, "kdc: failed to get KDC configuration", true);
 364                 return;
 365         }
 366
 367         kdc_config->logf = (krb5_log_facility *)kdc->smb_krb5_context->pvt_log_data;
 368         kdc_config->db = talloc(kdc, struct HDB *);
 369         if (!kdc_config->db) {
 370                 task_server_terminate(task, "kdc: out of memory", true);
 371                 return;
 372         }
 373         kdc_config->num_db = 1;
 374
 375         /*
 376          * Note with the CVE-2022-37966 patches,
 377          * see https://bugzilla.samba.org/show_bug.cgi?id=15219
 378          * and https://bugzilla.samba.org/show_bug.cgi?id=15237
 379          * we want to use the strongest keys for everything.
 380          *
 381          * Some of these don't have any real effect anymore,
 382          * but it is better to have them as true...
 383          */
 384         kdc_config->tgt_use_strongest_session_key = true;
 385         kdc_config->preauth_use_strongest_session_key = true;
 386         kdc_config->svc_use_strongest_session_key = true;
 387         kdc_config->use_strongest_server_key = true;
 388
 389         kdc_config->force_include_pa_etype_salt = true;
 390
 391         /*
 392          * For Samba CVE-2020-25719 Require PAC to be present
 393          * This instructs Heimdal to match AD behaviour,
 394          * as seen after Microsoft's CVE-2021-42287 when
 395          * PacRequestorEnforcement is set to 2.
 396          *
 397          * Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=14686
 398          * REF: https://support.microsoft.com/en-au/topic/kb5008380-authentication-updates-cve-2021-42287-9dafac11-e0d0-4cb8-959a-143bd0201041
 399          */
 400
 401         kdc_config->require_pac = true;
 402
 403         /*
 404          * By default we enable RFC6113/FAST support,
 405          * but we have an option to disable in order to
 406          * test against a KDC with FAST support.
 407          */
 408         kdc_config->enable_fast = lpcfg_kdc_enable_fast(task->lp_ctx);
 409
 410         {
 411                 static const char *dummy_string = "Microsoft";
 412
 413                 /*
 414                  * The FAST cookie is not cryptographically required,
 415                  * provided that the non-AD gss-preauth authentication
 416                  * method is removed (as this is the only multi-step
 417                  * authentication method).
 418                  *
 419                  * gss-preauth has been disabled both by not being
 420                  * configured and by being made dependent
 421                  * configuration for a "real" fast cookie.
 422                  *
 423                  * The hide_client_names feature in Heimdal is the
 424                  * only other state that is persisted in the cookie,
 425                  * and this does not need to be in the cookie for
 426                  * single-shot authentication protocols such as ENC-TS
 427                  * and ENC-CHAL, the standard password protocols in
 428                  * AD.
 429                  *
 430                  * Furthermore, the Heimdal KDC does not fail if the
 431                  * client does not supply a FAST cookie, showing that
 432                  * the presence of the cookie is not required.
 433                  */
 434                 kdc_config->enable_fast_cookie = false;
 435                 kdc_config->dummy_fast_cookie = smb_krb5_make_data(discard_const_p(char, dummy_string),
 436                                                                    strlen(dummy_string));
 437         }
 438
 439         /*
 440          * Match Windows and RFC6113 and Windows but break older
 441          * Heimdal clients.
 442          */
 443         kdc_config->enable_armored_pa_enc_timestamp = false;
 444
 445         /* Register hdb-samba4 hooks for use as a keytab */
 446
 447         kdc->base_ctx = talloc_zero(kdc, struct samba_kdc_base_context);
 448         if (!kdc->base_ctx) {
 449                 task_server_terminate(task, "kdc: out of memory", true);
 450                 return;
 451         }
 452
 453         kdc->base_ctx->ev_ctx = task->event_ctx;
 454         kdc->base_ctx->lp_ctx = task->lp_ctx;
 455         kdc->base_ctx->msg_ctx = task->msg_ctx;
 456
 457         kdc->base_ctx->current_nttime_ull = talloc_zero(kdc, unsigned long long);
 458         if (kdc->base_ctx->current_nttime_ull == NULL) {
 459                 task_server_terminate(task, "kdc: out of memory creating time variable", true);
 460                 return;
 461         }
 462
 463         status = hdb_samba4_create_kdc(kdc->base_ctx,
 464                                        kdc->smb_krb5_context->krb5_context,
 465                                        &kdc_config->db[0],
 466                                        &kdc->kdc_db_ctx);
 467         if (!NT_STATUS_IS_OK(status)) {
 468                 task_server_terminate(task, "kdc: hdb_samba4_create_kdc (setup KDC database) failed", true);
 469                 return;
 470         }
 471
 472         ldb_ret = samdb_rodc(kdc->kdc_db_ctx->samdb, &kdc->am_rodc);
 473         if (ldb_ret != LDB_SUCCESS) {
 474                 DBG_WARNING("kdc_task_init: "
 475                             "Cannot determine if we are an RODC: %s\n",
 476                             ldb_errstring(kdc->kdc_db_ctx->samdb));
 477                 task_server_terminate(task, "kdc: krb5_init_context samdb RODC query failed", true);
 478                 return;
 479         }
 480
 481         ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
 482                                    PLUGIN_TYPE_DATA, "hdb_samba4_interface",
 483                                    &hdb_samba4_interface);
 484         if(ret) {
 485                 task_server_terminate(task, "kdc: failed to register hdb plugin", true);
 486                 return;
 487         }
 488
 489         kdc->kpasswd_keytab_name = talloc_asprintf(kdc, "HDBGET:samba4:&%p", kdc->base_ctx);
 490         if (kdc->kpasswd_keytab_name == NULL) {
 491                 task_server_terminate(task,
 492                                       "kdc: Failed to set keytab name",
 493                                       true);
 494                 return;
 495         }
 496
 497         ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_get_kt_ops);
 498         if(ret) {
 499                 task_server_terminate(task, "kdc: failed to register keytab plugin", true);
 500                 return;
 501         }
 502
 503         /* Register KDC hooks */
 504         ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
 505                                    PLUGIN_TYPE_DATA, "kdc",
 506                                    &kdc_plugin_table);
 507         if(ret) {
 508                 task_server_terminate(task, "kdc: failed to register kdc plugin", true);
 509                 return;
 510         }
 511
 512         ret = krb5_kdc_plugin_init(kdc->smb_krb5_context->krb5_context);
 513
 514         if(ret) {
 515                 task_server_terminate(task, "kdc: failed to init kdc plugin", true);
 516                 return;
 517         }
 518
 519         ret = krb5_kdc_pkinit_config(kdc->smb_krb5_context->krb5_context, kdc_config);
 520
 521         if(ret) {
 522                 task_server_terminate(task, "kdc: failed to init kdc pkinit subsystem", true);
 523                 return;
 524         }
 525         kdc->private_data = kdc_config;
 526
 527         status = IRPC_REGISTER(task->msg_ctx, irpc, KDC_CHECK_GENERIC_KERBEROS,
 528                                kdc_check_generic_kerberos, kdc);
 529         if (!NT_STATUS_IS_OK(status)) {
 530                 task_server_terminate(task, "kdc failed to setup monitoring", true);
 531                 return;
 532         }
 533
 534         irpc_add_name(task->msg_ctx, "kdc_server");
 535 }
 536
 537
 538 /* called at smbd startup - register ourselves as a server service */
 539 NTSTATUS server_service_kdc_init(TALLOC_CTX *ctx)
 540 {
 541         static const struct service_details details = {
 542                 .inhibit_fork_on_accept = true,
 543                 .inhibit_pre_fork = false,
 544                 .task_init = kdc_task_init,
 545                 .post_fork = kdc_post_fork
 546         };
 547         return register_server_service(ctx, "kdc", &details);
 548 }