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 NTSTATUS server_service_kdc_init(TALLOC_CTX *);
  44
  45 extern struct krb5plugin_kdc_ftable kdc_plugin_table;
  46
  47 /**
  48    Wrapper for krb5_kdc_process_krb5_request, converting to/from Samba
  49    calling conventions
  50 */
  51
  52 static kdc_code kdc_process(struct kdc_server *kdc,
  53                             TALLOC_CTX *mem_ctx,
  54                             DATA_BLOB *input,
  55                             DATA_BLOB *reply,
  56                             struct tsocket_address *peer_addr,
  57                             struct tsocket_address *my_addr,
  58                             int datagram_reply)
  59 {
  60         int ret;
  61         char *pa;
  62         struct sockaddr_storage ss;
  63         krb5_data k5_reply;
  64         krb5_kdc_configuration *kdc_config =
  65                 (krb5_kdc_configuration *)kdc->private_data;
  66
  67         krb5_data_zero(&k5_reply);
  68
  69         krb5_kdc_update_time(NULL);
  70
  71         ret = tsocket_address_bsd_sockaddr(peer_addr, (struct sockaddr *) &ss,
  72                                 sizeof(struct sockaddr_storage));
  73         if (ret < 0) {
  74                 return KDC_ERROR;
  75         }
  76         pa = tsocket_address_string(peer_addr, mem_ctx);
  77         if (pa == NULL) {
  78                 return KDC_ERROR;
  79         }
  80
  81         DBG_DEBUG("Received KDC packet of length %lu from %s\n",
  82                   (long)input->length - 4, pa);
  83
  84         ret = krb5_kdc_process_krb5_request(kdc->smb_krb5_context->krb5_context,
  85                                             kdc_config,
  86                                             input->data, input->length,
  87                                             &k5_reply,
  88                                             pa,
  89                                             (struct sockaddr *) &ss,
  90                                             datagram_reply);
  91         if (ret == -1) {
  92                 *reply = data_blob(NULL, 0);
  93                 return KDC_ERROR;
  94         }
  95
  96         if (ret == HDB_ERR_NOT_FOUND_HERE) {
  97                 *reply = data_blob(NULL, 0);
  98                 return KDC_PROXY_REQUEST;
  99         }
 100
 101         if (k5_reply.length) {
 102                 *reply = data_blob_talloc(mem_ctx, k5_reply.data, k5_reply.length);
 103                 krb5_data_free(&k5_reply);
 104         } else {
 105                 *reply = data_blob(NULL, 0);
 106         }
 107         return KDC_OK;
 108 }
 109
 110 /*
 111   setup our listening sockets on the configured network interfaces
 112 */
 113 static NTSTATUS kdc_startup_interfaces(struct kdc_server *kdc,
 114                                        struct loadparm_context *lp_ctx,
 115                                        struct interface *ifaces,
 116                                        const struct model_ops *model_ops)
 117 {
 118         int num_interfaces;
 119         TALLOC_CTX *tmp_ctx = talloc_new(kdc);
 120         NTSTATUS status;
 121         int i;
 122         uint16_t kdc_port = lpcfg_krb5_port(lp_ctx);
 123         uint16_t kpasswd_port = lpcfg_kpasswd_port(lp_ctx);
 124         bool done_wildcard = false;
 125
 126         num_interfaces = iface_list_count(ifaces);
 127
 128         /* if we are allowing incoming packets from any address, then
 129            we need to bind to the wildcard address */
 130         if (!lpcfg_bind_interfaces_only(lp_ctx)) {
 131                 size_t num_binds = 0;
 132                 char **wcard = iface_list_wildcard(kdc);
 133                 NT_STATUS_HAVE_NO_MEMORY(wcard);
 134                 for (i=0; wcard[i]; i++) {
 135                         if (kdc_port) {
 136                                 status = kdc_add_socket(kdc, model_ops,
 137                                                         "kdc", wcard[i], kdc_port,
 138                                                         kdc_process, false);
 139                                 if (NT_STATUS_IS_OK(status)) {
 140                                         num_binds++;
 141                                 }
 142                         }
 143
 144                         if (kpasswd_port) {
 145                                 status = kdc_add_socket(kdc, model_ops,
 146                                                         "kpasswd", wcard[i], kpasswd_port,
 147                                                         kpasswd_process, false);
 148                                 if (NT_STATUS_IS_OK(status)) {
 149                                         num_binds++;
 150                                 }
 151                         }
 152                 }
 153                 talloc_free(wcard);
 154                 if (num_binds == 0) {
 155                         return NT_STATUS_INVALID_PARAMETER_MIX;
 156                 }
 157                 done_wildcard = true;
 158         }
 159
 160         for (i=0; i<num_interfaces; i++) {
 161                 const char *address = talloc_strdup(tmp_ctx, iface_list_n_ip(ifaces, i));
 162
 163                 if (kdc_port) {
 164                         status = kdc_add_socket(kdc, model_ops,
 165                                                 "kdc", address, kdc_port,
 166                                                 kdc_process, done_wildcard);
 167                         NT_STATUS_NOT_OK_RETURN(status);
 168                 }
 169
 170                 if (kpasswd_port) {
 171                         status = kdc_add_socket(kdc, model_ops,
 172                                                 "kpasswd", address, kpasswd_port,
 173                                                 kpasswd_process, done_wildcard);
 174                         NT_STATUS_NOT_OK_RETURN(status);
 175                 }
 176         }
 177
 178         talloc_free(tmp_ctx);
 179
 180         return NT_STATUS_OK;
 181 }
 182
 183 static NTSTATUS kdc_check_generic_kerberos(struct irpc_message *msg,
 184                                  struct kdc_check_generic_kerberos *r)
 185 {
 186         struct PAC_Validate pac_validate;
 187         DATA_BLOB srv_sig;
 188         struct PAC_SIGNATURE_DATA kdc_sig;
 189         struct kdc_server *kdc = talloc_get_type(msg->private_data, struct kdc_server);
 190         krb5_kdc_configuration *kdc_config =
 191                 (krb5_kdc_configuration *)kdc->private_data;
 192         enum ndr_err_code ndr_err;
 193         int ret;
 194         hdb_entry ent;
 195         krb5_principal principal;
 196
 197
 198         /* There is no reply to this request */
 199         r->out.generic_reply = data_blob(NULL, 0);
 200
 201         ndr_err = ndr_pull_struct_blob(&r->in.generic_request, msg, &pac_validate,
 202                                        (ndr_pull_flags_fn_t)ndr_pull_PAC_Validate);
 203         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 204                 return NT_STATUS_INVALID_PARAMETER;
 205         }
 206
 207         if (pac_validate.MessageType != NETLOGON_GENERIC_KRB5_PAC_VALIDATE) {
 208                 /* We don't implement any other message types - such as certificate validation - yet */
 209                 return NT_STATUS_INVALID_PARAMETER;
 210         }
 211
 212         if (pac_validate.ChecksumAndSignature.length != (pac_validate.ChecksumLength + pac_validate.SignatureLength)
 213             || pac_validate.ChecksumAndSignature.length < pac_validate.ChecksumLength
 214             || pac_validate.ChecksumAndSignature.length < pac_validate.SignatureLength ) {
 215                 return NT_STATUS_INVALID_PARAMETER;
 216         }
 217
 218         srv_sig = data_blob_const(pac_validate.ChecksumAndSignature.data,
 219                                   pac_validate.ChecksumLength);
 220
 221         ret = krb5_make_principal(kdc->smb_krb5_context->krb5_context, &principal,
 222                                   lpcfg_realm(kdc->task->lp_ctx),
 223                                   "krbtgt", lpcfg_realm(kdc->task->lp_ctx),
 224                                   NULL);
 225
 226         if (ret != 0) {
 227                 return NT_STATUS_NO_MEMORY;
 228         }
 229
 230         ret = kdc_config->db[0]->hdb_fetch_kvno(kdc->smb_krb5_context->krb5_context,
 231                                                  kdc_config->db[0],
 232                                                  principal,
 233                                                  HDB_F_GET_KRBTGT | HDB_F_DECRYPT,
 234                                                  0,
 235                                                  &ent);
 236
 237         if (ret != 0) {
 238                 hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
 239                 krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
 240
 241                 return NT_STATUS_LOGON_FAILURE;
 242         }
 243
 244         kdc_sig.type = pac_validate.SignatureType;
 245         kdc_sig.signature = data_blob_const(&pac_validate.ChecksumAndSignature.data[pac_validate.ChecksumLength],
 246                                             pac_validate.SignatureLength);
 247
 248         ret = kdc_check_pac(kdc->smb_krb5_context->krb5_context, srv_sig, &kdc_sig, &ent);
 249
 250         hdb_free_entry(kdc->smb_krb5_context->krb5_context, kdc_config->db[0], &ent);
 251         krb5_free_principal(kdc->smb_krb5_context->krb5_context, principal);
 252
 253         if (ret != 0) {
 254                 return NT_STATUS_LOGON_FAILURE;
 255         }
 256
 257         return NT_STATUS_OK;
 258 }
 259
 260
 261 /*
 262   startup the kdc task
 263 */
 264 static NTSTATUS kdc_task_init(struct task_server *task)
 265 {
 266         struct kdc_server *kdc;
 267         NTSTATUS status;
 268         struct interface *ifaces;
 269
 270         switch (lpcfg_server_role(task->lp_ctx)) {
 271         case ROLE_STANDALONE:
 272                 task_server_terminate(task, "kdc: no KDC required in standalone configuration", false);
 273                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 274         case ROLE_DOMAIN_MEMBER:
 275                 task_server_terminate(task, "kdc: no KDC required in member server configuration", false);
 276                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 277         case ROLE_DOMAIN_PDC:
 278         case ROLE_DOMAIN_BDC:
 279         case ROLE_IPA_DC:
 280                 task_server_terminate(
 281                     task, "Cannot start KDC as a 'classic Samba' DC", false);
 282                 return NT_STATUS_INVALID_DOMAIN_ROLE;
 283         case ROLE_ACTIVE_DIRECTORY_DC:
 284                 /* Yes, we want a KDC */
 285                 break;
 286         }
 287
 288         load_interface_list(task, task->lp_ctx, &ifaces);
 289
 290         if (iface_list_count(ifaces) == 0) {
 291                 task_server_terminate(task, "kdc: no network interfaces configured", false);
 292                 return NT_STATUS_UNSUCCESSFUL;
 293         }
 294
 295         task_server_set_title(task, "task[kdc]");
 296
 297         kdc = talloc_zero(task, struct kdc_server);
 298         if (kdc == NULL) {
 299                 task_server_terminate(task, "kdc: out of memory", true);
 300                 return NT_STATUS_NO_MEMORY;
 301         }
 302
 303         kdc->task = task;
 304         task->private_data = kdc;
 305
 306         /* start listening on the configured network interfaces */
 307         status = kdc_startup_interfaces(kdc, task->lp_ctx, ifaces,
 308                                         task->model_ops);
 309         if (!NT_STATUS_IS_OK(status)) {
 310                 task_server_terminate(task, "kdc failed to setup interfaces", true);
 311                 return status;
 312         }
 313
 314
 315         return NT_STATUS_OK;
 316 }
 317
 318 /*
 319   initialise the kdc task after a fork
 320 */
 321 static void kdc_post_fork(struct task_server *task, struct process_details *pd)
 322 {
 323         struct kdc_server *kdc;
 324         krb5_kdc_configuration *kdc_config = NULL;
 325         NTSTATUS status;
 326         krb5_error_code ret;
 327         int ldb_ret;
 328
 329         if (task == NULL) {
 330                 task_server_terminate(task, "kdc: Null task", true);
 331                 return;
 332         }
 333         if (task->private_data == NULL) {
 334                 task_server_terminate(task, "kdc: No kdc_server info", true);
 335                 return;
 336         }
 337         kdc = talloc_get_type_abort(task->private_data, struct kdc_server);
 338
 339         /* get a samdb connection */
 340         kdc->samdb = samdb_connect(kdc,
 341                                    kdc->task->event_ctx,
 342                                    kdc->task->lp_ctx,
 343                                    system_session(kdc->task->lp_ctx),
 344                                    NULL,
 345                                    0);
 346         if (!kdc->samdb) {
 347                 DBG_WARNING("kdc_task_init: unable to connect to samdb\n");
 348                 task_server_terminate(task, "kdc: krb5_init_context samdb connect failed", true);
 349                 return;
 350         }
 351
 352         ldb_ret = samdb_rodc(kdc->samdb, &kdc->am_rodc);
 353         if (ldb_ret != LDB_SUCCESS) {
 354                 DBG_WARNING("kdc_task_init: "
 355                             "Cannot determine if we are an RODC: %s\n",
 356                             ldb_errstring(kdc->samdb));
 357                 task_server_terminate(task, "kdc: krb5_init_context samdb RODC connect failed", true);
 358                 return;
 359         }
 360
 361         kdc->proxy_timeout = lpcfg_parm_int(kdc->task->lp_ctx, NULL, "kdc", "proxy timeout", 5);
 362
 363         initialize_krb5_error_table();
 364
 365         ret = smb_krb5_init_context(kdc, task->lp_ctx, &kdc->smb_krb5_context);
 366         if (ret) {
 367                 DBG_WARNING("kdc_task_init: krb5_init_context failed (%s)\n",
 368                             error_message(ret));
 369                 task_server_terminate(task, "kdc: krb5_init_context failed", true);
 370                 return;
 371         }
 372
 373         krb5_add_et_list(kdc->smb_krb5_context->krb5_context, initialize_hdb_error_table_r);
 374
 375         ret = krb5_kdc_get_config(kdc->smb_krb5_context->krb5_context,
 376                                   &kdc_config);
 377         if(ret) {
 378                 task_server_terminate(task, "kdc: failed to get KDC configuration", true);
 379                 return;
 380         }
 381
 382         kdc_config->logf = (krb5_log_facility *)kdc->smb_krb5_context->pvt_log_data;
 383         kdc_config->db = talloc(kdc, struct HDB *);
 384         if (!kdc_config->db) {
 385                 task_server_terminate(task, "kdc: out of memory", true);
 386                 return;
 387         }
 388         kdc_config->num_db = 1;
 389
 390         /*
 391          * This restores the behavior before
 392          * commit 255e3e18e00f717d99f3bc57c8a8895ff624f3c3
 393          * s4:heimdal: import lorikeet-heimdal-201107150856
 394          * (commit 48936803fae4a2fb362c79365d31f420c917b85b)
 395          *
 396          * as_use_strongest_session_key,preauth_use_strongest_session_key
 397          * and tgs_use_strongest_session_key are input to the
 398          * _kdc_find_etype() function. The old bahavior is in
 399          * the use_strongest_session_key=FALSE code path.
 400          * (The only remaining difference in _kdc_find_etype()
 401          *  is the is_preauth parameter.)
 402          *
 403          * The old behavior in the _kdc_get_preferred_key()
 404          * function is use_strongest_server_key=TRUE.
 405          */
 406         kdc_config->tgt_use_strongest_session_key = false;
 407         kdc_config->preauth_use_strongest_session_key = true;
 408         kdc_config->svc_use_strongest_session_key = false;
 409         kdc_config->use_strongest_server_key = true;
 410
 411         kdc_config->force_include_pa_etype_salt = true;
 412
 413         /*
 414          * For Samba CVE-2020-25719 Require PAC to be present
 415          * This instructs Heimdal to match AD behaviour,
 416          * as seen after Microsoft's CVE-2021-42287 when
 417          * PacRequestorEnforcement is set to 2.
 418          *
 419          * Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=14686
 420          * REF: https://support.microsoft.com/en-au/topic/kb5008380-authentication-updates-cve-2021-42287-9dafac11-e0d0-4cb8-959a-143bd0201041
 421          */
 422
 423         kdc_config->require_pac = true;
 424
 425         /*
 426          * By default we enable RFC6113/FAST support,
 427          * but we have an option to disable in order to
 428          * test against a KDC with FAST support.
 429          */
 430         kdc_config->enable_fast = lpcfg_kdc_enable_fast(task->lp_ctx);
 431
 432         /*
 433          * Match Windows and RFC6113 and Windows but break older
 434          * Heimdal clients.
 435          */
 436         kdc_config->enable_armored_pa_enc_timestamp = false;
 437
 438         /* Register hdb-samba4 hooks for use as a keytab */
 439
 440         kdc->base_ctx = talloc_zero(kdc, struct samba_kdc_base_context);
 441         if (!kdc->base_ctx) {
 442                 task_server_terminate(task, "kdc: out of memory", true);
 443                 return;
 444         }
 445
 446         kdc->base_ctx->ev_ctx = task->event_ctx;
 447         kdc->base_ctx->lp_ctx = task->lp_ctx;
 448         kdc->base_ctx->msg_ctx = task->msg_ctx;
 449
 450         status = hdb_samba4_create_kdc(kdc->base_ctx,
 451                                        kdc->smb_krb5_context->krb5_context,
 452                                        &kdc_config->db[0]);
 453         if (!NT_STATUS_IS_OK(status)) {
 454                 task_server_terminate(task, "kdc: hdb_samba4_create_kdc (setup KDC database) failed", true);
 455                 return;
 456         }
 457
 458         ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
 459                                    PLUGIN_TYPE_DATA, "hdb_samba4_interface",
 460                                    &hdb_samba4_interface);
 461         if(ret) {
 462                 task_server_terminate(task, "kdc: failed to register hdb plugin", true);
 463                 return;
 464         }
 465
 466         kdc->keytab_name = talloc_asprintf(kdc, "HDBGET:samba4:&%p", kdc->base_ctx);
 467         if (kdc->keytab_name == NULL) {
 468                 task_server_terminate(task,
 469                                       "kdc: Failed to set keytab name",
 470                                       true);
 471                 return;
 472         }
 473
 474         ret = krb5_kt_register(kdc->smb_krb5_context->krb5_context, &hdb_get_kt_ops);
 475         if(ret) {
 476                 task_server_terminate(task, "kdc: failed to register keytab plugin", true);
 477                 return;
 478         }
 479
 480         /* Register KDC hooks */
 481         ret = krb5_plugin_register(kdc->smb_krb5_context->krb5_context,
 482                                    PLUGIN_TYPE_DATA, "kdc",
 483                                    &kdc_plugin_table);
 484         if(ret) {
 485                 task_server_terminate(task, "kdc: failed to register kdc plugin", true);
 486                 return;
 487         }
 488
 489         ret = krb5_kdc_plugin_init(kdc->smb_krb5_context->krb5_context);
 490
 491         if(ret) {
 492                 task_server_terminate(task, "kdc: failed to init kdc plugin", true);
 493                 return;
 494         }
 495
 496         ret = krb5_kdc_pkinit_config(kdc->smb_krb5_context->krb5_context, kdc_config);
 497
 498         if(ret) {
 499                 task_server_terminate(task, "kdc: failed to init kdc pkinit subsystem", true);
 500                 return;
 501         }
 502         kdc->private_data = kdc_config;
 503
 504         status = IRPC_REGISTER(task->msg_ctx, irpc, KDC_CHECK_GENERIC_KERBEROS,
 505                                kdc_check_generic_kerberos, kdc);
 506         if (!NT_STATUS_IS_OK(status)) {
 507                 task_server_terminate(task, "kdc failed to setup monitoring", true);
 508                 return;
 509         }
 510
 511         irpc_add_name(task->msg_ctx, "kdc_server");
 512 }
 513
 514
 515 /* called at smbd startup - register ourselves as a server service */
 516 NTSTATUS server_service_kdc_init(TALLOC_CTX *ctx)
 517 {
 518         static const struct service_details details = {
 519                 .inhibit_fork_on_accept = true,
 520                 .inhibit_pre_fork = false,
 521                 .task_init = kdc_task_init,
 522                 .post_fork = kdc_post_fork
 523         };
 524         return register_server_service(ctx, "kdc", &details);
 525 }