source3/libads/kerberos.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    kerberos utility library
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Remus Koos 2001
   6    Copyright (C) Nalin Dahyabhai <nalin@redhat.com> 2004.
   7    Copyright (C) Jeremy Allison 2004.
   8    Copyright (C) Gerald Carter 2006.
   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 "system/filesys.h"
  26 #include "smb_krb5.h"
  27 #include "../librpc/gen_ndr/ndr_misc.h"
  28 #include "libads/kerberos_proto.h"
  29 #include "libads/cldap.h"
  30 #include "secrets.h"
  31 #include "../lib/tsocket/tsocket.h"
  32 #include "lib/util/asn1.h"
  33
  34 #ifdef HAVE_KRB5
  35
  36 #define LIBADS_CCACHE_NAME "MEMORY:libads"
  37
  38 /*
  39   we use a prompter to avoid a crash bug in the kerberos libs when
  40   dealing with empty passwords
  41   this prompter is just a string copy ...
  42 */
  43 static krb5_error_code
  44 kerb_prompter(krb5_context ctx, void *data,
  45                const char *name,
  46                const char *banner,
  47                int num_prompts,
  48                krb5_prompt prompts[])
  49 {
  50         if (num_prompts == 0) return 0;
  51         if (num_prompts == 2) {
  52                 /*
  53                  * only heimdal has a prompt type and we need to deal with it here to
  54                  * avoid loops.
  55                  *
  56                  * removing the prompter completely is not an option as at least these
  57                  * versions would crash: heimdal-1.0.2 and heimdal-1.1. Later heimdal
  58                  * version have looping detection and return with a proper error code.
  59                  */
  60
  61 #if HAVE_KRB5_PROMPT_TYPE /* Heimdal */
  62                  if (prompts[0].type == KRB5_PROMPT_TYPE_NEW_PASSWORD &&
  63                      prompts[1].type == KRB5_PROMPT_TYPE_NEW_PASSWORD_AGAIN) {
  64                         /*
  65                          * We don't want to change passwords here. We're
  66                          * called from heimal when the KDC returns
  67                          * KRB5KDC_ERR_KEY_EXPIRED, but at this point we don't
  68                          * have the chance to ask the user for a new
  69                          * password. If we return 0 (i.e. success), we will be
  70                          * spinning in the endless for-loop in
  71                          * change_password() in
  72                          * source4/heimdal/lib/krb5/init_creds_pw.c:526ff
  73                          */
  74                         return KRB5KDC_ERR_KEY_EXPIRED;
  75                 }
  76 #elif defined(HAVE_KRB5_GET_PROMPT_TYPES) /* MIT */
  77                 krb5_prompt_type *prompt_types = NULL;
  78
  79                 prompt_types = krb5_get_prompt_types(ctx);
  80                 if (prompt_types != NULL) {
  81                         if (prompt_types[0] == KRB5_PROMPT_TYPE_NEW_PASSWORD &&
  82                             prompt_types[1] == KRB5_PROMPT_TYPE_NEW_PASSWORD_AGAIN) {
  83                                 return KRB5KDC_ERR_KEY_EXP;
  84                         }
  85                 }
  86 #endif
  87         }
  88
  89         memset(prompts[0].reply->data, '\0', prompts[0].reply->length);
  90         if (prompts[0].reply->length > 0) {
  91                 if (data) {
  92                         strncpy((char *)prompts[0].reply->data, (const char *)data,
  93                                 prompts[0].reply->length-1);
  94                         prompts[0].reply->length = strlen((const char *)prompts[0].reply->data);
  95                 } else {
  96                         prompts[0].reply->length = 0;
  97                 }
  98         }
  99         return 0;
 100 }
 101
 102 /*
 103   simulate a kinit, putting the tgt in the given cache location. If cache_name == NULL
 104   place in default cache location.
 105   remus@snapserver.com
 106 */
 107 int kerberos_kinit_password_ext(const char *principal,
 108                                 const char *password,
 109                                 int time_offset,
 110                                 time_t *expire_time,
 111                                 time_t *renew_till_time,
 112                                 const char *cache_name,
 113                                 bool request_pac,
 114                                 bool add_netbios_addr,
 115                                 time_t renewable_time,
 116                                 NTSTATUS *ntstatus)
 117 {
 118         krb5_context ctx = NULL;
 119         krb5_error_code code = 0;
 120         krb5_ccache cc = NULL;
 121         krb5_principal me = NULL;
 122         krb5_principal canon_princ = NULL;
 123         krb5_creds my_creds;
 124         krb5_get_init_creds_opt *opt = NULL;
 125         smb_krb5_addresses *addr = NULL;
 126
 127         ZERO_STRUCT(my_creds);
 128
 129         initialize_krb5_error_table();
 130         if ((code = krb5_init_context(&ctx)))
 131                 goto out;
 132
 133         if (time_offset != 0) {
 134                 krb5_set_real_time(ctx, time(NULL) + time_offset, 0);
 135         }
 136
 137         DEBUG(10,("kerberos_kinit_password: as %s using [%s] as ccache and config [%s]\n",
 138                         principal,
 139                         cache_name ? cache_name: krb5_cc_default_name(ctx),
 140                         getenv("KRB5_CONFIG")));
 141
 142         if ((code = krb5_cc_resolve(ctx, cache_name ? cache_name : krb5_cc_default_name(ctx), &cc))) {
 143                 goto out;
 144         }
 145
 146         if ((code = smb_krb5_parse_name(ctx, principal, &me))) {
 147                 goto out;
 148         }
 149
 150         if ((code = krb5_get_init_creds_opt_alloc(ctx, &opt))) {
 151                 goto out;
 152         }
 153
 154         krb5_get_init_creds_opt_set_renew_life(opt, renewable_time);
 155         krb5_get_init_creds_opt_set_forwardable(opt, True);
 156
 157         /* Turn on canonicalization for lower case realm support */
 158 #ifndef SAMBA4_USES_HEIMDAL /* MIT */
 159         krb5_get_init_creds_opt_set_canonicalize(opt, true);
 160 #endif /* MIT */
 161 #if 0
 162         /* insane testing */
 163         krb5_get_init_creds_opt_set_tkt_life(opt, 60);
 164 #endif
 165
 166 #ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_SET_PAC_REQUEST
 167         if (request_pac) {
 168                 if ((code = krb5_get_init_creds_opt_set_pac_request(ctx, opt, (krb5_boolean)request_pac))) {
 169                         goto out;
 170                 }
 171         }
 172 #endif
 173         if (add_netbios_addr) {
 174                 if ((code = smb_krb5_gen_netbios_krb5_address(&addr,
 175                                                         lp_netbios_name()))) {
 176                         goto out;
 177                 }
 178                 krb5_get_init_creds_opt_set_address_list(opt, addr->addrs);
 179         }
 180
 181         if ((code = krb5_get_init_creds_password(ctx, &my_creds, me, discard_const_p(char,password),
 182                                                  kerb_prompter, discard_const_p(char, password),
 183                                                  0, NULL, opt))) {
 184                 goto out;
 185         }
 186
 187         canon_princ = me;
 188 #ifndef SAMBA4_USES_HEIMDAL /* MIT */
 189         canon_princ = my_creds.client;
 190 #endif /* MIT */
 191
 192         if ((code = krb5_cc_initialize(ctx, cc, canon_princ))) {
 193                 goto out;
 194         }
 195
 196         if ((code = krb5_cc_store_cred(ctx, cc, &my_creds))) {
 197                 goto out;
 198         }
 199
 200         if (expire_time) {
 201                 *expire_time = (time_t) my_creds.times.endtime;
 202         }
 203
 204         if (renew_till_time) {
 205                 *renew_till_time = (time_t) my_creds.times.renew_till;
 206         }
 207  out:
 208         if (ntstatus) {
 209                 /* fast path */
 210                 if (code == 0) {
 211                         *ntstatus = NT_STATUS_OK;
 212                         goto cleanup;
 213                 }
 214
 215                 /* fall back to self-made-mapping */
 216                 *ntstatus = krb5_to_nt_status(code);
 217         }
 218
 219  cleanup:
 220         krb5_free_cred_contents(ctx, &my_creds);
 221         if (me) {
 222                 krb5_free_principal(ctx, me);
 223         }
 224         if (addr) {
 225                 smb_krb5_free_addresses(ctx, addr);
 226         }
 227         if (opt) {
 228                 krb5_get_init_creds_opt_free(ctx, opt);
 229         }
 230         if (cc) {
 231                 krb5_cc_close(ctx, cc);
 232         }
 233         if (ctx) {
 234                 krb5_free_context(ctx);
 235         }
 236         return code;
 237 }
 238
 239 int ads_kdestroy(const char *cc_name)
 240 {
 241         krb5_error_code code;
 242         krb5_context ctx = NULL;
 243         krb5_ccache cc = NULL;
 244
 245         initialize_krb5_error_table();
 246         if ((code = krb5_init_context (&ctx))) {
 247                 DEBUG(3, ("ads_kdestroy: kdb5_init_context failed: %s\n",
 248                         error_message(code)));
 249                 return code;
 250         }
 251
 252         if (!cc_name) {
 253                 if ((code = krb5_cc_default(ctx, &cc))) {
 254                         krb5_free_context(ctx);
 255                         return code;
 256                 }
 257         } else {
 258                 if ((code = krb5_cc_resolve(ctx, cc_name, &cc))) {
 259                         DEBUG(3, ("ads_kdestroy: krb5_cc_resolve failed: %s\n",
 260                                   error_message(code)));
 261                         krb5_free_context(ctx);
 262                         return code;
 263                 }
 264         }
 265
 266         if ((code = krb5_cc_destroy (ctx, cc))) {
 267                 DEBUG(3, ("ads_kdestroy: krb5_cc_destroy failed: %s\n",
 268                         error_message(code)));
 269         }
 270
 271         krb5_free_context (ctx);
 272         return code;
 273 }
 274
 275 int create_kerberos_key_from_string(krb5_context context,
 276                                         krb5_principal host_princ,
 277                                         krb5_principal salt_princ,
 278                                         krb5_data *password,
 279                                         krb5_keyblock *key,
 280                                         krb5_enctype enctype,
 281                                         bool no_salt)
 282 {
 283         int ret;
 284         /*
 285          * Check if we've determined that the KDC is salting keys for this
 286          * principal/enctype in a non-obvious way.  If it is, try to match
 287          * its behavior.
 288          */
 289         if (no_salt) {
 290                 KRB5_KEY_DATA(key) = (KRB5_KEY_DATA_CAST *)SMB_MALLOC(password->length);
 291                 if (!KRB5_KEY_DATA(key)) {
 292                         return ENOMEM;
 293                 }
 294                 memcpy(KRB5_KEY_DATA(key), password->data, password->length);
 295                 KRB5_KEY_LENGTH(key) = password->length;
 296                 KRB5_KEY_TYPE(key) = enctype;
 297                 return 0;
 298         }
 299         ret = smb_krb5_create_key_from_string(context,
 300                                               salt_princ ? salt_princ : host_princ,
 301                                               NULL,
 302                                               password,
 303                                               enctype,
 304                                               key);
 305         return ret;
 306 }
 307
 308 /************************************************************************
 309 ************************************************************************/
 310
 311 int kerberos_kinit_password(const char *principal,
 312                             const char *password,
 313                             int time_offset,
 314                             const char *cache_name)
 315 {
 316         return kerberos_kinit_password_ext(principal,
 317                                            password,
 318                                            time_offset,
 319                                            0,
 320                                            0,
 321                                            cache_name,
 322                                            False,
 323                                            False,
 324                                            0,
 325                                            NULL);
 326 }
 327
 328 /************************************************************************
 329 ************************************************************************/
 330
 331 /************************************************************************
 332  Create a string list of available kdc's, possibly searching by sitename.
 333  Does DNS queries.
 334
 335  If "sitename" is given, the DC's in that site are listed first.
 336
 337 ************************************************************************/
 338
 339 static void add_sockaddr_unique(struct sockaddr_storage *addrs, size_t *num_addrs,
 340                                 const struct sockaddr_storage *addr)
 341 {
 342         size_t i;
 343
 344         for (i=0; i<*num_addrs; i++) {
 345                 if (sockaddr_equal((const struct sockaddr *)&addrs[i],
 346                                    (const struct sockaddr *)addr)) {
 347                         return;
 348                 }
 349         }
 350         addrs[i] = *addr;
 351         *num_addrs += 1;
 352 }
 353
 354 /* print_canonical_sockaddr prints an ipv6 addr in the form of
 355 * [ipv6.addr]. This string, when put in a generated krb5.conf file is not
 356 * always properly dealt with by some older krb5 libraries. Adding the hard-coded
 357 * portnumber workarounds the issue. - gd */
 358
 359 static char *print_canonical_sockaddr_with_port(TALLOC_CTX *mem_ctx,
 360                                                 const struct sockaddr_storage *pss)
 361 {
 362         char *str = NULL;
 363
 364         str = print_canonical_sockaddr(mem_ctx, pss);
 365         if (str == NULL) {
 366                 return NULL;
 367         }
 368
 369         if (pss->ss_family != AF_INET6) {
 370                 return str;
 371         }
 372
 373 #if defined(HAVE_IPV6)
 374         str = talloc_asprintf_append(str, ":88");
 375 #endif
 376         return str;
 377 }
 378
 379 static char *get_kdc_ip_string(char *mem_ctx,
 380                 const char *realm,
 381                 const char *sitename,
 382                 const struct sockaddr_storage *pss)
 383 {
 384         TALLOC_CTX *frame = talloc_stackframe();
 385         size_t i;
 386         struct ip_service *ip_srv_site = NULL;
 387         struct ip_service *ip_srv_nonsite = NULL;
 388         int count_site = 0;
 389         int count_nonsite;
 390         size_t num_dcs;
 391         struct sockaddr_storage *dc_addrs;
 392         struct tsocket_address **dc_addrs2 = NULL;
 393         const struct tsocket_address * const *dc_addrs3 = NULL;
 394         char *result = NULL;
 395         struct netlogon_samlogon_response **responses = NULL;
 396         NTSTATUS status;
 397         char *kdc_str = talloc_asprintf(mem_ctx, "%s\t\tkdc = %s\n", "",
 398                                         print_canonical_sockaddr_with_port(mem_ctx, pss));
 399
 400         if (kdc_str == NULL) {
 401                 TALLOC_FREE(frame);
 402                 return NULL;
 403         }
 404
 405         /*
 406          * First get the KDC's only in this site, the rest will be
 407          * appended later
 408          */
 409
 410         if (sitename) {
 411                 get_kdc_list(realm, sitename, &ip_srv_site, &count_site);
 412                 DEBUG(10, ("got %d addresses from site %s search\n", count_site,
 413                            sitename));
 414         }
 415
 416         /* Get all KDC's. */
 417
 418         get_kdc_list(realm, NULL, &ip_srv_nonsite, &count_nonsite);
 419         DEBUG(10, ("got %d addresses from site-less search\n", count_nonsite));
 420
 421         dc_addrs = talloc_array(talloc_tos(), struct sockaddr_storage,
 422                                 count_site + count_nonsite);
 423         if (dc_addrs == NULL) {
 424                 goto out;
 425         }
 426
 427         num_dcs = 0;
 428
 429         for (i = 0; i < count_site; i++) {
 430                 if (!sockaddr_equal(
 431                         (const struct sockaddr *)pss,
 432                         (const struct sockaddr *)&ip_srv_site[i].ss)) {
 433                         add_sockaddr_unique(dc_addrs, &num_dcs,
 434                                             &ip_srv_site[i].ss);
 435                 }
 436         }
 437
 438         for (i = 0; i < count_nonsite; i++) {
 439                 if (!sockaddr_equal(
 440                         (const struct sockaddr *)pss,
 441                         (const struct sockaddr *)&ip_srv_nonsite[i].ss)) {
 442                         add_sockaddr_unique(dc_addrs, &num_dcs,
 443                                             &ip_srv_nonsite[i].ss);
 444                 }
 445         }
 446
 447         dc_addrs2 = talloc_zero_array(talloc_tos(),
 448                                       struct tsocket_address *,
 449                                       num_dcs);
 450
 451         DBG_DEBUG("%zu additional KDCs to test\n", num_dcs);
 452         if (num_dcs == 0) {
 453                 goto out;
 454         }
 455         if (dc_addrs2 == NULL) {
 456                 goto out;
 457         }
 458
 459         for (i=0; i<num_dcs; i++) {
 460                 char addr[INET6_ADDRSTRLEN];
 461                 int ret;
 462
 463                 print_sockaddr(addr, sizeof(addr), &dc_addrs[i]);
 464
 465                 ret = tsocket_address_inet_from_strings(dc_addrs2, "ip",
 466                                                         addr, LDAP_PORT,
 467                                                         &dc_addrs2[i]);
 468                 if (ret != 0) {
 469                         status = map_nt_error_from_unix(errno);
 470                         DEBUG(2,("Failed to create tsocket_address for %s - %s\n",
 471                                  addr, nt_errstr(status)));
 472                         goto out;
 473                 }
 474         }
 475
 476         dc_addrs3 = (const struct tsocket_address * const *)dc_addrs2;
 477
 478         status = cldap_multi_netlogon(talloc_tos(),
 479                         dc_addrs3, num_dcs,
 480                         realm, lp_netbios_name(),
 481                         NETLOGON_NT_VERSION_5 | NETLOGON_NT_VERSION_5EX,
 482                         MIN(num_dcs, 3), timeval_current_ofs(3, 0), &responses);
 483         TALLOC_FREE(dc_addrs2);
 484         dc_addrs3 = NULL;
 485
 486         if (!NT_STATUS_IS_OK(status)) {
 487                 DEBUG(10,("get_kdc_ip_string: cldap_multi_netlogon failed: "
 488                           "%s\n", nt_errstr(status)));
 489                 goto out;
 490         }
 491
 492         for (i=0; i<num_dcs; i++) {
 493                 char *new_kdc_str;
 494
 495                 if (responses[i] == NULL) {
 496                         continue;
 497                 }
 498
 499                 /* Append to the string - inefficient but not done often. */
 500                 new_kdc_str = talloc_asprintf(mem_ctx, "%s\t\tkdc = %s\n",
 501                                               kdc_str,
 502                                               print_canonical_sockaddr_with_port(mem_ctx, &dc_addrs[i]));
 503                 if (new_kdc_str == NULL) {
 504                         goto out;
 505                 }
 506                 TALLOC_FREE(kdc_str);
 507                 kdc_str = new_kdc_str;
 508         }
 509
 510 out:
 511         DEBUG(10, ("get_kdc_ip_string: Returning %s\n", kdc_str));
 512
 513         result = kdc_str;
 514         SAFE_FREE(ip_srv_site);
 515         SAFE_FREE(ip_srv_nonsite);
 516         TALLOC_FREE(frame);
 517         return result;
 518 }
 519
 520 /************************************************************************
 521  Create  a specific krb5.conf file in the private directory pointing
 522  at a specific kdc for a realm. Keyed off domain name. Sets
 523  KRB5_CONFIG environment variable to point to this file. Must be
 524  run as root or will fail (which is a good thing :-).
 525 ************************************************************************/
 526
 527 #if !defined(SAMBA4_USES_HEIMDAL) /* MIT version */
 528 static char *get_enctypes(TALLOC_CTX *mem_ctx)
 529 {
 530         char *aes_enctypes = NULL;
 531         const char *legacy_enctypes = "";
 532         char *enctypes = NULL;
 533
 534         aes_enctypes = talloc_strdup(mem_ctx, "");
 535         if (aes_enctypes == NULL) {
 536                 goto done;
 537         }
 538
 539         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 540             lp_kerberos_encryption_types() == KERBEROS_ETYPES_STRONG) {
 541 #ifdef HAVE_ENCTYPE_AES256_CTS_HMAC_SHA1_96
 542                 aes_enctypes = talloc_asprintf_append(
 543                     aes_enctypes, "%s", "aes256-cts-hmac-sha1-96 ");
 544                 if (aes_enctypes == NULL) {
 545                         goto done;
 546                 }
 547 #endif
 548 #ifdef HAVE_ENCTYPE_AES128_CTS_HMAC_SHA1_96
 549                 aes_enctypes = talloc_asprintf_append(
 550                     aes_enctypes, "%s", "aes128-cts-hmac-sha1-96");
 551                 if (aes_enctypes == NULL) {
 552                         goto done;
 553                 }
 554 #endif
 555         }
 556
 557         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 558             lp_kerberos_encryption_types() == KERBEROS_ETYPES_LEGACY) {
 559                 legacy_enctypes = "RC4-HMAC DES-CBC-CRC DES-CBC-MD5";
 560         }
 561
 562         enctypes =
 563             talloc_asprintf(mem_ctx, "\tdefault_tgs_enctypes = %s %s\n"
 564                                      "\tdefault_tkt_enctypes = %s %s\n"
 565                                      "\tpreferred_enctypes = %s %s\n",
 566                             aes_enctypes, legacy_enctypes, aes_enctypes,
 567                             legacy_enctypes, aes_enctypes, legacy_enctypes);
 568 done:
 569         TALLOC_FREE(aes_enctypes);
 570         return enctypes;
 571 }
 572 #else /* Heimdal version */
 573 static char *get_enctypes(TALLOC_CTX *mem_ctx)
 574 {
 575         const char *aes_enctypes = "";
 576         const char *legacy_enctypes = "";
 577         char *enctypes = NULL;
 578
 579         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 580             lp_kerberos_encryption_types() == KERBEROS_ETYPES_STRONG) {
 581                 aes_enctypes =
 582                     "aes256-cts-hmac-sha1-96 aes128-cts-hmac-sha1-96";
 583         }
 584
 585         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 586             lp_kerberos_encryption_types() == KERBEROS_ETYPES_LEGACY) {
 587                 legacy_enctypes = "arcfour-hmac-md5 des-cbc-crc des-cbc-md5";
 588         }
 589
 590         enctypes = talloc_asprintf(mem_ctx, "\tdefault_etypes = %s %s\n",
 591                                    aes_enctypes, legacy_enctypes);
 592
 593         return enctypes;
 594 }
 595 #endif
 596
 597 bool create_local_private_krb5_conf_for_domain(const char *realm,
 598                                                 const char *domain,
 599                                                 const char *sitename,
 600                                                 const struct sockaddr_storage *pss)
 601 {
 602         char *dname;
 603         char *tmpname = NULL;
 604         char *fname = NULL;
 605         char *file_contents = NULL;
 606         char *kdc_ip_string = NULL;
 607         size_t flen = 0;
 608         ssize_t ret;
 609         int fd;
 610         char *realm_upper = NULL;
 611         bool result = false;
 612         char *enctypes = NULL;
 613         const char *include_system_krb5 = "";
 614         mode_t mask;
 615
 616         if (!lp_create_krb5_conf()) {
 617                 return false;
 618         }
 619
 620         if (realm == NULL) {
 621                 DEBUG(0, ("No realm has been specified! Do you really want to "
 622                           "join an Active Directory server?\n"));
 623                 return false;
 624         }
 625
 626         if (domain == NULL || pss == NULL) {
 627                 return false;
 628         }
 629
 630         dname = lock_path("smb_krb5");
 631         if (!dname) {
 632                 return false;
 633         }
 634         if ((mkdir(dname, 0755)==-1) && (errno != EEXIST)) {
 635                 DEBUG(0,("create_local_private_krb5_conf_for_domain: "
 636                         "failed to create directory %s. Error was %s\n",
 637                         dname, strerror(errno) ));
 638                 goto done;
 639         }
 640
 641         tmpname = lock_path("smb_tmp_krb5.XXXXXX");
 642         if (!tmpname) {
 643                 goto done;
 644         }
 645
 646         fname = talloc_asprintf(dname, "%s/krb5.conf.%s", dname, domain);
 647         if (!fname) {
 648                 goto done;
 649         }
 650
 651         DEBUG(10,("create_local_private_krb5_conf_for_domain: fname = %s, realm = %s, domain = %s\n",
 652                 fname, realm, domain ));
 653
 654         realm_upper = talloc_strdup(fname, realm);
 655         if (!strupper_m(realm_upper)) {
 656                 goto done;
 657         }
 658
 659         kdc_ip_string = get_kdc_ip_string(dname, realm, sitename, pss);
 660         if (!kdc_ip_string) {
 661                 goto done;
 662         }
 663
 664         enctypes = get_enctypes(fname);
 665         if (enctypes == NULL) {
 666                 goto done;
 667         }
 668
 669 #if !defined(SAMBA4_USES_HEIMDAL)
 670         if (lp_include_system_krb5_conf()) {
 671                 include_system_krb5 = "include /etc/krb5.conf";
 672         }
 673 #endif
 674
 675         file_contents =
 676             talloc_asprintf(fname,
 677                             "[libdefaults]\n\tdefault_realm = %s\n"
 678                             "%s"
 679                             "\tdns_lookup_realm = false\n\n"
 680                             "[realms]\n\t%s = {\n"
 681                             "%s\t}\n"
 682                             "%s\n",
 683                             realm_upper,
 684                             enctypes,
 685                             realm_upper,
 686                             kdc_ip_string,
 687                             include_system_krb5);
 688
 689         if (!file_contents) {
 690                 goto done;
 691         }
 692
 693         flen = strlen(file_contents);
 694
 695         mask = umask(S_IRWXO | S_IRWXG);
 696         fd = mkstemp(tmpname);
 697         umask(mask);
 698         if (fd == -1) {
 699                 DEBUG(0,("create_local_private_krb5_conf_for_domain: smb_mkstemp failed,"
 700                         " for file %s. Errno %s\n",
 701                         tmpname, strerror(errno) ));
 702                 goto done;
 703         }
 704
 705         if (fchmod(fd, 0644)==-1) {
 706                 DEBUG(0,("create_local_private_krb5_conf_for_domain: fchmod failed for %s."
 707                         " Errno %s\n",
 708                         tmpname, strerror(errno) ));
 709                 unlink(tmpname);
 710                 close(fd);
 711                 goto done;
 712         }
 713
 714         ret = write(fd, file_contents, flen);
 715         if (flen != ret) {
 716                 DEBUG(0,("create_local_private_krb5_conf_for_domain: write failed,"
 717                         " returned %d (should be %u). Errno %s\n",
 718                         (int)ret, (unsigned int)flen, strerror(errno) ));
 719                 unlink(tmpname);
 720                 close(fd);
 721                 goto done;
 722         }
 723         if (close(fd)==-1) {
 724                 DEBUG(0,("create_local_private_krb5_conf_for_domain: close failed."
 725                         " Errno %s\n", strerror(errno) ));
 726                 unlink(tmpname);
 727                 goto done;
 728         }
 729
 730         if (rename(tmpname, fname) == -1) {
 731                 DEBUG(0,("create_local_private_krb5_conf_for_domain: rename "
 732                         "of %s to %s failed. Errno %s\n",
 733                         tmpname, fname, strerror(errno) ));
 734                 unlink(tmpname);
 735                 goto done;
 736         }
 737
 738         DEBUG(5,("create_local_private_krb5_conf_for_domain: wrote "
 739                 "file %s with realm %s KDC list = %s\n",
 740                 fname, realm_upper, kdc_ip_string));
 741
 742         /* Set the environment variable to this file. */
 743         setenv("KRB5_CONFIG", fname, 1);
 744
 745         result = true;
 746
 747 #if defined(OVERWRITE_SYSTEM_KRB5_CONF)
 748
 749 #define SYSTEM_KRB5_CONF_PATH "/etc/krb5.conf"
 750         /* Insanity, sheer insanity..... */
 751
 752         if (strequal(realm, lp_realm())) {
 753                 SMB_STRUCT_STAT sbuf;
 754
 755                 if (sys_lstat(SYSTEM_KRB5_CONF_PATH, &sbuf, false) == 0) {
 756                         if (S_ISLNK(sbuf.st_ex_mode) && sbuf.st_ex_size) {
 757                                 int lret;
 758                                 size_t alloc_size = sbuf.st_ex_size + 1;
 759                                 char *linkpath = talloc_array(talloc_tos(), char,
 760                                                 alloc_size);
 761                                 if (!linkpath) {
 762                                         goto done;
 763                                 }
 764                                 lret = readlink(SYSTEM_KRB5_CONF_PATH, linkpath,
 765                                                 alloc_size - 1);
 766                                 if (lret == -1) {
 767                                         TALLOC_FREE(linkpath);
 768                                         goto done;
 769                                 }
 770                                 linkpath[lret] = '\0';
 771
 772                                 if (strcmp(linkpath, fname) == 0) {
 773                                         /* Symlink already exists. */
 774                                         TALLOC_FREE(linkpath);
 775                                         goto done;
 776                                 }
 777                                 TALLOC_FREE(linkpath);
 778                         }
 779                 }
 780
 781                 /* Try and replace with a symlink. */
 782                 if (symlink(fname, SYSTEM_KRB5_CONF_PATH) == -1) {
 783                         const char *newpath = SYSTEM_KRB5_CONF_PATH ".saved";
 784                         if (errno != EEXIST) {
 785                                 DEBUG(0,("create_local_private_krb5_conf_for_domain: symlink "
 786                                         "of %s to %s failed. Errno %s\n",
 787                                         fname, SYSTEM_KRB5_CONF_PATH, strerror(errno) ));
 788                                 goto done; /* Not a fatal error. */
 789                         }
 790
 791                         /* Yes, this is a race conditon... too bad. */
 792                         if (rename(SYSTEM_KRB5_CONF_PATH, newpath) == -1) {
 793                                 DEBUG(0,("create_local_private_krb5_conf_for_domain: rename "
 794                                         "of %s to %s failed. Errno %s\n",
 795                                         SYSTEM_KRB5_CONF_PATH, newpath,
 796                                         strerror(errno) ));
 797                                 goto done; /* Not a fatal error. */
 798                         }
 799
 800                         if (symlink(fname, SYSTEM_KRB5_CONF_PATH) == -1) {
 801                                 DEBUG(0,("create_local_private_krb5_conf_for_domain: "
 802                                         "forced symlink of %s to /etc/krb5.conf failed. Errno %s\n",
 803                                         fname, strerror(errno) ));
 804                                 goto done; /* Not a fatal error. */
 805                         }
 806                 }
 807         }
 808 #endif
 809
 810 done:
 811         TALLOC_FREE(tmpname);
 812         TALLOC_FREE(dname);
 813
 814         return result;
 815 }
 816 #endif