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 =
  68                 (krb5_kdc_configuration *)kdc->private_data;
  69
  70         krb5_data_zero(&k5_reply);
  71
  72         krb5_kdc_update_time(NULL);
  73
  74         ret = tsocket_address_bsd_sockaddr(peer_addr, (struct sockaddr *) &ss,
  75                                 sizeof(struct sockaddr_storage));
  76         if (ret < 0) {
  77                 return KDC_ERROR;
  78         }
  79         pa = tsocket_address_string(peer_addr, mem_ctx);
  80         if (pa == NULL) {
  81                 return KDC_ERROR;
  82         }
  83
  84         DBG_DEBUG("Received KDC packet of length %lu from %s\n",
  85                   (long)input->length - 4, pa);
  86
  87         ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
  88                                             kdc_config,
  89                                             input->data, input->length,
  90                                             &k5_reply,
  91                                             pa,
  92                                             (struct sockaddr *) &ss,
  93                                             datagram_reply);
  94         if (ret == -1) {
  95                 *reply = data_blob(NULL, 0);
  96                 return KDC_ERROR;
  97         }
  98
  99         if (ret == HDB_ERR_NOT_FOUND_HERE) {
 100                 *reply = data_blob(NULL, 0);
 101                 return KDC_PROXY_REQUEST;
 102         }
 103
 104         if (k5_reply.length) {
 105                 *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
 106                 krb5_data_free(&k5_reply);
 107         } else {
 108                 *reply = data_blob(NULL, 0);
 109         }
 110         return KDC_OK;
 111 }
 112
 113 /*
 114   setup our listening sockets on the configured network interfaces
 115 */
 116 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc,
 117                                        struct loadparm_context *lp_ctx,
 118                                        struct interface *ifaces,
 119                                        const struct model_ops *model_ops)
 120 {
 121         int num_interfaces;
 122         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 123         NTSTATUS status;
 124         int i;
 125         uint16_t kdc_port = lpcfg_krb5_port(lp_ctx);
 126         uint16_t kpasswd_port = lpcfg_kpasswd_port(lp_ctx);
 127         bool done_wildcard = false;
 128
 129         num_interfaces = iface_list_count(ifaces);
 130
 131         /* if we are allowing incoming packets from any address, then
 132            we need to bind to the wildcard address */
 133         if (!lpcfg_bind_interfaces_only(lp_ctx)) {
 134                 size_t num_binds = 0;
 135                 char **wcard = iface_list_wildcard(kdc);
 136                 NT_STATUS_HAVE_NO_MEMORY(wcard);
 137                 for (i=0; wcard[i]; i++) {
 138                         if (kdc_port) {
 139                                 status = kdc_add_socket(kdc, model_ops,
 140                                                         "kdc", wcard[i], kdc_port,
 141                                                         kdc_process, false);
 142                                 if (NT_STATUS_IS_OK(status)) {
 143                                         num_binds++;
 144                                 }
 145                         }
 146
 147                         if (kpasswd_port) {
 148                                 status = kdc_add_socket(kdc, model_ops,
 149                                                         "kpasswd", wcard[i], kpasswd_port,
 150                                                         kpasswd_process, false);
 151                                 if (NT_STATUS_IS_OK(status)) {
 152                                         num_binds++;
 153                                 }
 154                         }
 155                 }
 156                 talloc_free(wcard);
 157                 if (num_binds == 0) {
 158                         return NT_STATUS_INVALID_PARAMETER_MIX;
 159                 }
 160                 done_wildcard = true;
 161         }
 162
 163         for (i=0; i<num_interfaces; i++) {
 164                 const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
 165
 166                 if (kdc_port) {
 167                         status = kdc_add_socket(kdc, model_ops,
 168                                                 "kdc", address, kdc_port,
 169                                                 kdc_process, done_wildcard);
 170                         NT_STATUS_NOT_OK_RETURN(status);
 171                 }
 172
 173                 if (kpasswd_port) {
 174                         status = kdc_add_socket(kdc, model_ops,
 175                                                 "kpasswd", address, kpasswd_port,
 176                                                 kpasswd_process, done_wildcard);
 177                         NT_STATUS_NOT_OK_RETURN(status);
 178                 }
 179         }
 180
 181         talloc_free(tmp_ctx);
 182
 183         return NT_STATUS_OK;
 184 }
 185
 186 static NTSTATUS kdc_check_generic_kerberos(struct irpc_message *msg,
 187                                  struct kdc_check_generic_kerberos *r)
 188 {
 189         struct PAC_Validate pac_validate;
 190         DATA_BLOB srv_sig;
 191         struct PAC_SIGNATURE_DATA kdc_sig;
 192         struct kdc_server *kdc = talloc_get_type(msg->private_data, struct kdc_server);
 193         krb5_kdc_configuration *kdc_config =
 194                 (krb5_kdc_configuration *)kdc->private_data;
 195         enum ndr_err_code ndr_err;
 196         int ret;
 197         hdb_entry ent;
 198         krb5_principal principal;
 199
 200
 201         /* There is no reply to this request */
 202         r->out.generic_reply = data_blob(NULL, 0);
 203
 204         ndr_err = ndr_pull_struct_blob(&r->in.generic_request, msg, &pac_validate,
 205                                        (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
 206         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 207                 return NT_STATUS_INVALID_PARAMETER;
 208         }
 209
 210         if (pac_validate.MessageType != NETLOGON_GENERIC_KRB5_PAC_VALIDATE) {
 211                 /* We don't implement any other message types - such as certificate validation - yet */
 212                 return NT_STATUS_INVALID_PARAMETER;
 213         }
 214
 215         if (pac_validate.ChecksumAndSignature.length != (pac_validate.ChecksumLength + pac_validate.SignatureLength)
 216             || pac_validate.ChecksumAndSignature.length < pac_validate.ChecksumLength
 217             || pac_validate.ChecksumAndSignature.length < pac_validate.SignatureLength ) {
 218                 return NT_STATUS_INVALID_PARAMETER;
 219         }
 220
 221         srv_sig = data_blob_const(pac_validate.ChecksumAndSignature.data,
 222                                   pac_validate.ChecksumLength);
 223
 224         ret = krb5_make_principal(kdc->smb_krb5_context->krb5_context, &principal,
 225                                   lpcfg_realm(kdc->task->lp_ctx),
 226                                   "krbtgt", lpcfg_realm(kdc->task->lp_ctx),
 227                                   NULL);
 228
 229         if (ret != 0) {
 230                 return NT_STATUS_NO_MEMORY;
 231         }
 232
 233         ret = kdc_config->db[0]->hdb_fetch_kvno(kdc->smb_krb5_context->krb5_context,
 234                                                  kdc_config->db[0],
 235                                                  principal,
 236                                                  HDB_F_GET_KRBTGT | HDB_F_DECRYPT,
 237                                                  0,
 238                                                  &ent);
 239
 240         if (ret != 0) {
 241                 hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
 242                 krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
 243
 244                 return NT_STATUS_LOGON_FAILURE;
 245         }
 246
 247         kdc_sig.type = pac_validate.SignatureType;
 248         kdc_sig.signature = data_blob_const(&pac_validate.ChecksumAndSignature.data[pac_validate.ChecksumLength],
 249                                             pac_validate.SignatureLength);
 250
 251         ret = kdc_check_pac(kdc->smb_krb5_context->krb5_context, srv_sig, &kdc_sig, &ent);
 252
 253         hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
 254         krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
 255
 256         if (ret != 0) {
 257                 return NT_STATUS_LOGON_FAILURE;
 258         }
 259
 260         return NT_STATUS_OK;
 261 }
 262
 263
 264 /*
 265   startup the kdc task
 266 */
 267 static NTSTATUS kdc_task_init(struct task_server *task)
 268 {
 269         struct kdc_server *kdc;
 270         NTSTATUS status;
 271         struct interface *ifaces;
 272
 273         switch (lpcfg_server_role(task->lp_ctx)) {
 274         case ROLE_STANDALONE:
 275                 task_server_terminate(task, "kdc: no KDC required in standalone configuration", false);
 276                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 277         case ROLE_DOMAIN_MEMBER:
 278                 task_server_terminate(task, "kdc: no KDC required in member server configuration", false);
 279                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 280         case ROLE_DOMAIN_PDC:
 281         case ROLE_DOMAIN_BDC:
 282         case ROLE_IPA_DC:
 283                 task_server_terminate(
 284                     task, "Cannot start KDC as a 'classic Samba' DC", false);
 285                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 286         case ROLE_ACTIVE_DIRECTORY_DC:
 287                 /* Yes, we want a KDC */
 288                 break;
 289         }
 290
 291         load_interface_list(task, task->lp_ctx, &ifaces);
 292
 293         if (iface_list_count(ifaces) == 0) {
 294                 task_server_terminate(task, "kdc: no network interfaces configured", false);
 295                 return NT_STATUS_UNSUCCESSFUL;
 296         }
 297
 298         task_server_set_title(task, "task[kdc]");
 299
 300         kdc = talloc_zero(task, struct kdc_server);
 301         if (kdc == NULL) {
 302                 task_server_terminate(task, "kdc: out of memory", true);
 303                 return NT_STATUS_NO_MEMORY;
 304         }
 305
 306         kdc->task = task;
 307         task->private_data = kdc;
 308
 309         /* start listening on the configured network interfaces */
 310         status = kdc_startup_interfaces(kdc, task->lp_ctx, ifaces,
 311                                         task->model_ops);
 312         if (!NT_STATUS_IS_OK(status)) {
 313                 task_server_terminate(task, "kdc failed to setup interfaces", true);
 314                 return status;
 315         }
 316
 317
 318         return NT_STATUS_OK;
 319 }
 320
 321 /*
 322   initialise the kdc task after a fork
 323 */
 324 static void kdc_post_fork(struct task_server *task, struct process_details *pd)
 325 {
 326         struct kdc_server *kdc;
 327         krb5_kdc_configuration *kdc_config = NULL;
 328         NTSTATUS status;
 329         krb5_error_code ret;
 330         int ldb_ret;
 331
 332         if (task == NULL) {
 333                 task_server_terminate(task, "kdc: Null task", true);
 334                 return;
 335         }
 336         if (task->private_data == NULL) {
 337                 task_server_terminate(task, "kdc: No kdc_server info", true);
 338                 return;
 339         }
 340         kdc = talloc_get_type_abort(task->private_data, struct kdc_server);
 341
 342         /* get a samdb connection */
 343         kdc->samdb = samdb_connect(kdc,
 344                                    kdc->task->event_ctx,
 345                                    kdc->task->lp_ctx,
 346                                    system_session(kdc->task->lp_ctx),
 347                                    NULL,
 348                                    0);
 349         if (!kdc->samdb) {
 350                 DBG_WARNING("kdc_task_init: unable to connect to samdb\n");
 351                 task_server_terminate(task, "kdc: krb5_init_context samdb connect failed", true);
 352                 return;
 353         }
 354
 355         ldb_ret = samdb_rodc(kdc->samdb, &kdc->am_rodc);
 356         if (ldb_ret != LDB_SUCCESS) {
 357                 DBG_WARNING("kdc_task_init: "
 358                             "Cannot determine if we are an RODC: %s\n",
 359                             ldb_errstring(kdc->samdb));
 360                 task_server_terminate(task, "kdc: krb5_init_context samdb RODC connect failed", true);
 361                 return;
 362         }
 363
 364         kdc->proxy_timeout = lpcfg_parm_int(kdc->task->lp_ctx, NULL, "kdc", "proxy timeout", 5);
 365
 366         initialize_krb5_error_table();
 367
 368         ret = smb_krb5_init_context(kdc, task->lp_ctx, &kdc->smb_krb5_context);
 369         if (ret) {
 370                 DBG_WARNING("kdc_task_init: krb5_init_context failed (%s)\n",
 371                             error_message(ret));
 372                 task_server_terminate(task, "kdc: krb5_init_context failed", true);
 373                 return;
 374         }
 375
 376         krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
 377
 378         ret = krb5_kdc_get_config(kdc->smb_krb5_context->krb5_context,
 379                                   &kdc_config);
 380         if(ret) {
 381                 task_server_terminate(task, "kdc: failed to get KDC configuration", true);
 382                 return;
 383         }
 384
 385         kdc_config->logf = (krb5_log_facility *)kdc->smb_krb5_context->pvt_log_data;
 386         kdc_config->db = talloc(kdc, struct HDB *);
 387         if (!kdc_config->db) {
 388                 task_server_terminate(task, "kdc: out of memory", true);
 389                 return;
 390         }
 391         kdc_config->num_db = 1;
 392
 393         /*
 394          * This restores the behavior before
 395          * commit 255e3e18e00f717d99f3bc57c8a8895ff624f3c3
 396          * s4:heimdal: import lorikeet-heimdal-201107150856
 397          * (commit 48936803fae4a2fb362c79365d31f420c917b85b)
 398          *
 399          * as_use_strongest_session_key,preauth_use_strongest_session_key
 400          * and tgs_use_strongest_session_key are input to the
 401          * _kdc_find_etype() function. The old bahavior is in
 402          * the use_strongest_session_key=FALSE code path.
 403          * (The only remaining difference in _kdc_find_etype()
 404          *  is the is_preauth parameter.)
 405          *
 406          * The old behavior in the _kdc_get_preferred_key()
 407          * function is use_strongest_server_key=TRUE.
 408          */
 409         kdc_config->tgt_use_strongest_session_key = false;
 410         kdc_config->preauth_use_strongest_session_key = true;
 411         kdc_config->svc_use_strongest_session_key = false;
 412         kdc_config->use_strongest_server_key = true;
 413
 414         kdc_config->force_include_pa_etype_salt = true;
 415
 416         /*
 417          * For Samba CVE-2020-25719 Require PAC to be present
 418          * This instructs Heimdal to match AD behaviour,
 419          * as seen after Microsoft's CVE-2021-42287 when
 420          * PacRequestorEnforcement is set to 2.
 421          *
 422          * Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=14686
 423          * REF: https://support.microsoft.com/en-au/topic/kb5008380-authentication-updates-cve-2021-42287-9dafac11-e0d0-4cb8-959a-143bd0201041
 424          */
 425
 426         kdc_config->require_pac = true;
 427
 428         /*
 429          * By default we enable RFC6113/FAST support,
 430          * but we have an option to disable in order to
 431          * test against a KDC with FAST support.
 432          */
 433         kdc_config->enable_fast = lpcfg_kdc_enable_fast(task->lp_ctx);
 434
 435         /*
 436          * Match Windows and RFC6113 and Windows but break older
 437          * Heimdal clients.
 438          */
 439         kdc_config->enable_armored_pa_enc_timestamp = false;
 440
 441         /* Register hdb-samba4 hooks for use as a keytab */
 442
 443         kdc->base_ctx = talloc_zero(kdc, struct samba_kdc_base_context);
 444         if (!kdc->base_ctx) {
 445                 task_server_terminate(task, "kdc: out of memory", true);
 446                 return;
 447         }
 448
 449         kdc->base_ctx->ev_ctx = task->event_ctx;
 450         kdc->base_ctx->lp_ctx = task->lp_ctx;
 451         kdc->base_ctx->msg_ctx = task->msg_ctx;
 452
 453         status = hdb_samba4_create_kdc(kdc->base_ctx,
 454                                        kdc->smb_krb5_context->krb5_context,
 455                                        &kdc_config->db[0]);
 456         if (!NT_STATUS_IS_OK(status)) {
 457                 task_server_terminate(task, "kdc: hdb_samba4_create_kdc (setup KDC database) failed", true);
 458                 return;
 459         }
 460
 461         ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
 462                                    PLUGIN_TYPE_DATA, "hdb_samba4_interface",
 463                                    &hdb_samba4_interface);
 464         if(ret) {
 465                 task_server_terminate(task, "kdc: failed to register hdb plugin", true);
 466                 return;
 467         }
 468
 469         kdc->kpasswd_keytab_name = talloc_asprintf(kdc, "HDBGET:samba4:&%p", kdc->base_ctx);
 470         if (kdc->kpasswd_keytab_name == NULL) {
 471                 task_server_terminate(task,
 472                                       "kdc: Failed to set keytab name",
 473                                       true);
 474                 return;
 475         }
 476
 477         ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_get_kt_ops);
 478         if(ret) {
 479                 task_server_terminate(task, "kdc: failed to register keytab plugin", true);
 480                 return;
 481         }
 482
 483         /* Register KDC hooks */
 484         ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
 485                                    PLUGIN_TYPE_DATA, "kdc",
 486                                    &kdc_plugin_table);
 487         if(ret) {
 488                 task_server_terminate(task, "kdc: failed to register kdc plugin", true);
 489                 return;
 490         }
 491
 492         ret = krb5_kdc_plugin_init(kdc->smb_krb5_context->krb5_context);
 493
 494         if(ret) {
 495                 task_server_terminate(task, "kdc: failed to init kdc plugin", true);
 496                 return;
 497         }
 498
 499         ret = krb5_kdc_pkinit_config(kdc->smb_krb5_context->krb5_context, kdc_config);
 500
 501         if(ret) {
 502                 task_server_terminate(task, "kdc: failed to init kdc pkinit subsystem", true);
 503                 return;
 504         }
 505         kdc->private_data = kdc_config;
 506
 507         status = IRPC_REGISTER(task->msg_ctx, irpc, KDC_CHECK_GENERIC_KERBEROS,
 508                                kdc_check_generic_kerberos, kdc);
 509         if (!NT_STATUS_IS_OK(status)) {
 510                 task_server_terminate(task, "kdc failed to setup monitoring", true);
 511                 return;
 512         }
 513
 514         irpc_add_name(task->msg_ctx, "kdc_server");
 515 }
 516
 517
 518 /* called at smbd startup - register ourselves as a server service */
 519 NTSTATUS server_service_kdc_init(TALLOC_CTX *ctx)
 520 {
 521         static const struct service_details details = {
 522                 .inhibit_fork_on_accept = true,
 523                 .inhibit_pre_fork = false,
 524                 .task_init = kdc_task_init,
 525                 .post_fork = kdc_post_fork
 526         };
 527         return register_server_service(ctx, "kdc", &details);
 528 }