source4/kdc/pac-glue.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3
   4    PAC Glue between Samba and the KDC
   5
   6    Copyright (C) Andrew Bartlett <abartlet@samba.org> 2005-2009
   7    Copyright (C) Simo Sorce <idra@samba.org> 2010
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  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 "../libds/common/flags.h"
  26 #include <ldb.h>
  27 #include "auth/auth.h"
  28 #include "auth/auth_sam_reply.h"
  29 #include "system/kerberos.h"
  30 #include "auth/kerberos/kerberos.h"
  31 #include <hdb.h>
  32 #include "kdc/samba_kdc.h"
  33 #include "kdc/pac-glue.h"
  34 #include "param/param.h"
  35 #include "librpc/gen_ndr/ndr_krb5pac.h"
  36 #include "libcli/security/security.h"
  37 #include "dsdb/samdb/samdb.h"
  38 #include "auth/kerberos/pac_utils.h"
  39
  40 static
  41 NTSTATUS samba_get_logon_info_pac_blob(TALLOC_CTX *mem_ctx,
  42                                        struct auth_user_info_dc *info,
  43                                        DATA_BLOB *pac_data)
  44 {
  45         struct netr_SamInfo3 *info3;
  46         union PAC_INFO pac_info;
  47         enum ndr_err_code ndr_err;
  48         NTSTATUS nt_status;
  49
  50         ZERO_STRUCT(pac_info);
  51
  52         nt_status = auth_convert_user_info_dc_saminfo3(mem_ctx, info, &info3);
  53         if (!NT_STATUS_IS_OK(nt_status)) {
  54                 DEBUG(1, ("Getting Samba info failed: %s\n",
  55                           nt_errstr(nt_status)));
  56                 return nt_status;
  57         }
  58
  59         pac_info.logon_info.info = talloc_zero(mem_ctx, struct PAC_LOGON_INFO);
  60         if (!pac_info.logon_info.info) {
  61                 return NT_STATUS_NO_MEMORY;
  62         }
  63
  64         pac_info.logon_info.info->info3 = *info3;
  65
  66         ndr_err = ndr_push_union_blob(pac_data, mem_ctx, &pac_info,
  67                                       PAC_TYPE_LOGON_INFO,
  68                                       (ndr_push_flags_fn_t)ndr_push_PAC_INFO);
  69         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
  70                 nt_status = ndr_map_error2ntstatus(ndr_err);
  71                 DEBUG(1, ("PAC (presig) push failed: %s\n",
  72                           nt_errstr(nt_status)));
  73                 return nt_status;
  74         }
  75
  76         return NT_STATUS_OK;
  77 }
  78
  79 krb5_error_code samba_make_krb5_pac(krb5_context context,
  80                                     DATA_BLOB *pac_blob,
  81                                     DATA_BLOB *deleg_blob,
  82                                     krb5_pac *pac)
  83 {
  84         krb5_data pac_data;
  85         krb5_data deleg_data;
  86         krb5_error_code ret;
  87
  88         /* The user account may be set not to want the PAC */
  89         if (!pac_blob) {
  90                 return 0;
  91         }
  92
  93         ret = krb5_copy_data_contents(&pac_data,
  94                                       pac_blob->data,
  95                                       pac_blob->length);
  96         if (ret != 0) {
  97                 return ret;
  98         }
  99
 100         ZERO_STRUCT(deleg_data);
 101         if (deleg_blob) {
 102                 ret = krb5_copy_data_contents(&deleg_data,
 103                                               deleg_blob->data,
 104                                               deleg_blob->length);
 105                 if (ret != 0) {
 106                         kerberos_free_data_contents(context, &pac_data);
 107                         return ret;
 108                 }
 109         }
 110
 111         ret = krb5_pac_init(context, pac);
 112         if (ret != 0) {
 113                 kerberos_free_data_contents(context, &pac_data);
 114                 kerberos_free_data_contents(context, &deleg_data);
 115                 return ret;
 116         }
 117
 118         ret = krb5_pac_add_buffer(context, *pac, PAC_TYPE_LOGON_INFO, &pac_data);
 119         kerberos_free_data_contents(context, &pac_data);
 120         if (ret != 0) {
 121                 kerberos_free_data_contents(context, &deleg_data);
 122                 return ret;
 123         }
 124
 125         if (deleg_blob) {
 126                 ret = krb5_pac_add_buffer(context, *pac,
 127                                           PAC_TYPE_CONSTRAINED_DELEGATION,
 128                                           &deleg_data);
 129                 kerberos_free_data_contents(context, &deleg_data);
 130                 if (ret != 0) {
 131                         return ret;
 132                 }
 133         }
 134
 135         return ret;
 136 }
 137
 138 bool samba_princ_needs_pac(struct samba_kdc_entry *skdc_entry)
 139 {
 140
 141         uint32_t userAccountControl;
 142
 143         /* The service account may be set not to want the PAC */
 144         userAccountControl = ldb_msg_find_attr_as_uint(skdc_entry->msg, "userAccountControl", 0);
 145         if (userAccountControl & UF_NO_AUTH_DATA_REQUIRED) {
 146                 return false;
 147         }
 148
 149         return true;
 150 }
 151
 152 /* Was the krbtgt in this DB (ie, should we check the incoming signature) and was it an RODC */
 153 int samba_krbtgt_is_in_db(struct samba_kdc_entry *p,
 154                           bool *is_in_db,
 155                           bool *is_untrusted)
 156 {
 157         NTSTATUS status;
 158         int rodc_krbtgt_number, trust_direction;
 159         uint32_t rid;
 160
 161         TALLOC_CTX *mem_ctx = talloc_new(NULL);
 162         if (!mem_ctx) {
 163                 return ENOMEM;
 164         }
 165
 166         trust_direction = ldb_msg_find_attr_as_int(p->msg, "trustDirection", 0);
 167
 168         if (trust_direction != 0) {
 169                 /* Domain trust - we cannot check the sig, but we trust it for a correct PAC
 170
 171                    This is exactly where we should flag for SID
 172                    validation when we do inter-foreest trusts
 173                  */
 174                 talloc_free(mem_ctx);
 175                 *is_untrusted = false;
 176                 *is_in_db = false;
 177                 return 0;
 178         }
 179
 180         /* The lack of password controls etc applies to krbtgt by
 181          * virtue of being that particular RID */
 182         status = dom_sid_split_rid(NULL, samdb_result_dom_sid(mem_ctx, p->msg, "objectSid"), NULL, &rid);
 183
 184         if (!NT_STATUS_IS_OK(status)) {
 185                 talloc_free(mem_ctx);
 186                 return EINVAL;
 187         }
 188
 189         rodc_krbtgt_number = ldb_msg_find_attr_as_int(p->msg, "msDS-SecondaryKrbTgtNumber", -1);
 190
 191         if (p->kdc_db_ctx->my_krbtgt_number == 0) {
 192                 if (rid == DOMAIN_RID_KRBTGT) {
 193                         *is_untrusted = false;
 194                         *is_in_db = true;
 195                         talloc_free(mem_ctx);
 196                         return 0;
 197                 } else if (rodc_krbtgt_number != -1) {
 198                         *is_in_db = true;
 199                         *is_untrusted = true;
 200                         talloc_free(mem_ctx);
 201                         return 0;
 202                 }
 203         } else if ((rid != DOMAIN_RID_KRBTGT) && (rodc_krbtgt_number == p->kdc_db_ctx->my_krbtgt_number)) {
 204                 talloc_free(mem_ctx);
 205                 *is_untrusted = false;
 206                 *is_in_db = true;
 207                 return 0;
 208         } else if (rid == DOMAIN_RID_KRBTGT) {
 209                 /* krbtgt viewed from an RODC */
 210                 talloc_free(mem_ctx);
 211                 *is_untrusted = false;
 212                 *is_in_db = false;
 213                 return 0;
 214         }
 215
 216         /* Another RODC */
 217         talloc_free(mem_ctx);
 218         *is_untrusted = true;
 219         *is_in_db = false;
 220         return 0;
 221 }
 222
 223 NTSTATUS samba_kdc_get_pac_blob(TALLOC_CTX *mem_ctx,
 224                                 struct samba_kdc_entry *p,
 225                                 DATA_BLOB **_pac_blob)
 226 {
 227         struct auth_user_info_dc *user_info_dc;
 228         DATA_BLOB *pac_blob;
 229         NTSTATUS nt_status;
 230
 231         /* The user account may be set not to want the PAC */
 232         if ( ! samba_princ_needs_pac(p)) {
 233                 *_pac_blob = NULL;
 234                 return NT_STATUS_OK;
 235         }
 236
 237         pac_blob = talloc_zero(mem_ctx, DATA_BLOB);
 238         if (!pac_blob) {
 239                 return NT_STATUS_NO_MEMORY;
 240         }
 241
 242         nt_status = authsam_make_user_info_dc(mem_ctx, p->kdc_db_ctx->samdb,
 243                                              lpcfg_netbios_name(p->kdc_db_ctx->lp_ctx),
 244                                              lpcfg_sam_name(p->kdc_db_ctx->lp_ctx),
 245                                              p->realm_dn,
 246                                              p->msg,
 247                                              data_blob(NULL, 0),
 248                                              data_blob(NULL, 0),
 249                                              &user_info_dc);
 250         if (!NT_STATUS_IS_OK(nt_status)) {
 251                 DEBUG(0, ("Getting user info for PAC failed: %s\n",
 252                           nt_errstr(nt_status)));
 253                 return nt_status;
 254         }
 255
 256         nt_status = samba_get_logon_info_pac_blob(mem_ctx, user_info_dc, pac_blob);
 257         if (!NT_STATUS_IS_OK(nt_status)) {
 258                 DEBUG(0, ("Building PAC failed: %s\n",
 259                           nt_errstr(nt_status)));
 260                 return nt_status;
 261         }
 262
 263         *_pac_blob = pac_blob;
 264         return NT_STATUS_OK;
 265 }
 266
 267 NTSTATUS samba_kdc_update_pac_blob(TALLOC_CTX *mem_ctx,
 268                                    krb5_context context,
 269                                    const krb5_pac pac, DATA_BLOB *pac_blob,
 270                                    struct PAC_SIGNATURE_DATA *pac_srv_sig,
 271                                    struct PAC_SIGNATURE_DATA *pac_kdc_sig)
 272 {
 273         struct auth_user_info_dc *user_info_dc;
 274         krb5_error_code ret;
 275         NTSTATUS nt_status;
 276
 277         ret = kerberos_pac_to_user_info_dc(mem_ctx, pac,
 278                                            context, &user_info_dc, pac_srv_sig, pac_kdc_sig);
 279         if (ret) {
 280                 return NT_STATUS_UNSUCCESSFUL;
 281         }
 282
 283         nt_status = samba_get_logon_info_pac_blob(mem_ctx,
 284                                                   user_info_dc, pac_blob);
 285
 286         return nt_status;
 287 }
 288
 289 NTSTATUS samba_kdc_update_delegation_info_blob(TALLOC_CTX *mem_ctx,
 290                                 krb5_context context,
 291                                 const krb5_pac pac,
 292                                 const krb5_principal server_principal,
 293                                 const krb5_principal proxy_principal,
 294                                 DATA_BLOB *new_blob)
 295 {
 296         krb5_data old_data;
 297         DATA_BLOB old_blob;
 298         krb5_error_code ret;
 299         NTSTATUS nt_status;
 300         enum ndr_err_code ndr_err;
 301         union PAC_INFO info;
 302         struct PAC_CONSTRAINED_DELEGATION _d;
 303         struct PAC_CONSTRAINED_DELEGATION *d = NULL;
 304         char *server = NULL;
 305         char *proxy = NULL;
 306         uint32_t i;
 307         TALLOC_CTX *tmp_ctx = talloc_new(mem_ctx);
 308
 309         if (tmp_ctx == NULL) {
 310                 return NT_STATUS_NO_MEMORY;
 311         }
 312
 313         ret = krb5_pac_get_buffer(context, pac, PAC_TYPE_CONSTRAINED_DELEGATION, &old_data);
 314         if (ret == ENOENT) {
 315                 ZERO_STRUCT(old_data);
 316         } else if (ret) {
 317                 talloc_free(tmp_ctx);
 318                 return NT_STATUS_UNSUCCESSFUL;
 319         }
 320
 321         old_blob.length = old_data.length;
 322         old_blob.data = (uint8_t *)old_data.data;
 323
 324         ZERO_STRUCT(info);
 325         if (old_blob.length > 0) {
 326                 ndr_err = ndr_pull_union_blob(&old_blob, mem_ctx,
 327                                 &info, PAC_TYPE_CONSTRAINED_DELEGATION,
 328                                 (ndr_pull_flags_fn_t)ndr_pull_PAC_INFO);
 329                 if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 330                         kerberos_free_data_contents(context, &old_data);
 331                         nt_status = ndr_map_error2ntstatus(ndr_err);
 332                         DEBUG(0,("can't parse the PAC LOGON_INFO: %s\n", nt_errstr(nt_status)));
 333                         talloc_free(tmp_ctx);
 334                         return nt_status;
 335                 }
 336         } else {
 337                 ZERO_STRUCT(_d);
 338                 info.constrained_delegation.info = &_d;
 339         }
 340         kerberos_free_data_contents(context, &old_data);
 341
 342         ret = krb5_unparse_name(context, server_principal, &server);
 343         if (ret) {
 344                 talloc_free(tmp_ctx);
 345                 return NT_STATUS_INTERNAL_ERROR;
 346         }
 347
 348         ret = krb5_unparse_name_flags(context, proxy_principal,
 349                                       KRB5_PRINCIPAL_UNPARSE_NO_REALM, &proxy);
 350         if (ret) {
 351                 SAFE_FREE(server);
 352                 talloc_free(tmp_ctx);
 353                 return NT_STATUS_INTERNAL_ERROR;
 354         }
 355
 356         d = info.constrained_delegation.info;
 357         i = d->num_transited_services;
 358         d->proxy_target.string = server;
 359         d->transited_services = talloc_realloc(mem_ctx, d->transited_services,
 360                                                struct lsa_String, i + 1);
 361         d->transited_services[i].string = proxy;
 362         d->num_transited_services = i + 1;
 363
 364         ndr_err = ndr_push_union_blob(new_blob, mem_ctx,
 365                                 &info, PAC_TYPE_CONSTRAINED_DELEGATION,
 366                                 (ndr_push_flags_fn_t)ndr_push_PAC_INFO);
 367         SAFE_FREE(server);
 368         SAFE_FREE(proxy);
 369         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 370                 kerberos_free_data_contents(context, &old_data);
 371                 nt_status = ndr_map_error2ntstatus(ndr_err);
 372                 DEBUG(0,("can't parse the PAC LOGON_INFO: %s\n", nt_errstr(nt_status)));
 373                 talloc_free(tmp_ctx);
 374                 return nt_status;
 375         }
 376
 377         talloc_free(tmp_ctx);
 378         return NT_STATUS_OK;
 379 }
 380
 381 /* this function allocates 'data' using malloc.
 382  * The caller is responsible for freeing it */
 383 void samba_kdc_build_edata_reply(NTSTATUS nt_status, DATA_BLOB *e_data)
 384 {
 385         PA_DATA pa;
 386         unsigned char *buf;
 387         size_t len;
 388         krb5_error_code ret = 0;
 389
 390         if (!e_data)
 391                 return;
 392
 393         pa.padata_type          = KRB5_PADATA_PW_SALT;
 394         pa.padata_value.length  = 12;
 395         pa.padata_value.data    = malloc(pa.padata_value.length);
 396         if (!pa.padata_value.data) {
 397                 e_data->length = 0;
 398                 e_data->data = NULL;
 399                 return;
 400         }
 401
 402         SIVAL(pa.padata_value.data, 0, NT_STATUS_V(nt_status));
 403         SIVAL(pa.padata_value.data, 4, 0);
 404         SIVAL(pa.padata_value.data, 8, 1);
 405
 406         ASN1_MALLOC_ENCODE(PA_DATA, buf, len, &pa, &len, ret);
 407         free(pa.padata_value.data);
 408
 409         e_data->data   = buf;
 410         e_data->length = len;
 411
 412         return;
 413 }
 414
 415 /* function to map policy errors */
 416 krb5_error_code samba_kdc_map_policy_err(NTSTATUS nt_status)
 417 {
 418         krb5_error_code ret;
 419
 420         if (NT_STATUS_EQUAL(nt_status, NT_STATUS_PASSWORD_MUST_CHANGE))
 421                 ret = KRB5KDC_ERR_KEY_EXP;
 422         else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_PASSWORD_EXPIRED))
 423                 ret = KRB5KDC_ERR_KEY_EXP;
 424         else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_ACCOUNT_EXPIRED))
 425                 ret = KRB5KDC_ERR_CLIENT_REVOKED;
 426         else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_ACCOUNT_DISABLED))
 427                 ret = KRB5KDC_ERR_CLIENT_REVOKED;
 428         else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_INVALID_LOGON_HOURS))
 429                 ret = KRB5KDC_ERR_CLIENT_REVOKED;
 430         else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_ACCOUNT_LOCKED_OUT))
 431                 ret = KRB5KDC_ERR_CLIENT_REVOKED;
 432         else if (NT_STATUS_EQUAL(nt_status, NT_STATUS_INVALID_WORKSTATION))
 433                 ret = KRB5KDC_ERR_POLICY;
 434         else
 435                 ret = KRB5KDC_ERR_POLICY;
 436
 437         return ret;
 438 }
 439
 440 /* Given a kdc entry, consult the account_ok routine in auth/auth_sam.c
 441  * for consistency */
 442 NTSTATUS samba_kdc_check_client_access(struct samba_kdc_entry *kdc_entry,
 443                                        const char *client_name,
 444                                        const char *workstation,
 445                                        bool password_change)
 446 {
 447         TALLOC_CTX *tmp_ctx;
 448         NTSTATUS nt_status;
 449
 450         tmp_ctx = talloc_named(NULL, 0, "samba_kdc_check_client_access");
 451         if (!tmp_ctx) {
 452                 return NT_STATUS_NO_MEMORY;
 453         }
 454
 455         /* we allow all kinds of trusts here */
 456         nt_status = authsam_account_ok(tmp_ctx,
 457                                        kdc_entry->kdc_db_ctx->samdb,
 458                                        MSV1_0_ALLOW_SERVER_TRUST_ACCOUNT |
 459                                        MSV1_0_ALLOW_WORKSTATION_TRUST_ACCOUNT,
 460                                        kdc_entry->realm_dn, kdc_entry->msg,
 461                                        workstation, client_name,
 462                                        true, password_change);
 463
 464         talloc_free(tmp_ctx);
 465         return nt_status;
 466 }
 467
 468 int kdc_check_pac(krb5_context context,
 469                   DATA_BLOB srv_sig,
 470                   struct PAC_SIGNATURE_DATA *kdc_sig,
 471                   hdb_entry_ex *ent)
 472 {
 473         krb5_enctype etype;
 474         int ret;
 475         krb5_keyblock keyblock;
 476         Key *key;
 477         if (kdc_sig->type == CKSUMTYPE_HMAC_MD5) {
 478                 etype = ENCTYPE_ARCFOUR_HMAC;
 479         } else {
 480                 ret = krb5_cksumtype_to_enctype(context,
 481                                                 kdc_sig->type,
 482                                                 &etype);
 483                 if (ret != 0) {
 484                         return ret;
 485                 }
 486         }
 487
 488 #if HDB_ENCTYPE2KEY_TAKES_KEYSET
 489         ret = hdb_enctype2key(context, &ent->entry, NULL, etype, &key);
 490 #else
 491         ret = hdb_enctype2key(context, &ent->entry, etype, &key);
 492 #endif
 493
 494         if (ret != 0) {
 495                 return ret;
 496         }
 497
 498         keyblock = key->key;
 499
 500         return check_pac_checksum(srv_sig, kdc_sig,
 501                                  context, &keyblock);
 502 }
 503
 504
 505