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 "libsmb/namequery.h"
  26 #include "system/filesys.h"
  27 #include "smb_krb5.h"
  28 #include "../librpc/gen_ndr/ndr_misc.h"
  29 #include "libads/kerberos_proto.h"
  30 #include "libads/cldap.h"
  31 #include "secrets.h"
  32 #include "../lib/tsocket/tsocket.h"
  33 #include "lib/util/asn1.h"
  34 #include "krb5_errs.h"
  35
  36 #ifdef HAVE_KRB5
  37
  38 #define LIBADS_CCACHE_NAME "MEMORY:libads"
  39
  40 /*
  41   we use a prompter to avoid a crash bug in the kerberos libs when
  42   dealing with empty passwords
  43   this prompter is just a string copy ...
  44 */
  45 static krb5_error_code
  46 kerb_prompter(krb5_context ctx, void *data,
  47                const char *name,
  48                const char *banner,
  49                int num_prompts,
  50                krb5_prompt prompts[])
  51 {
  52         if (num_prompts == 0) return 0;
  53         if (num_prompts == 2) {
  54                 /*
  55                  * only heimdal has a prompt type and we need to deal with it here to
  56                  * avoid loops.
  57                  *
  58                  * removing the prompter completely is not an option as at least these
  59                  * versions would crash: heimdal-1.0.2 and heimdal-1.1. Later heimdal
  60                  * version have looping detection and return with a proper error code.
  61                  */
  62
  63 #if defined(HAVE_KRB5_PROMPT_TYPE) /* Heimdal */
  64                  if (prompts[0].type == KRB5_PROMPT_TYPE_NEW_PASSWORD &&
  65                      prompts[1].type == KRB5_PROMPT_TYPE_NEW_PASSWORD_AGAIN) {
  66                         /*
  67                          * We don't want to change passwords here. We're
  68                          * called from heimal when the KDC returns
  69                          * KRB5KDC_ERR_KEY_EXPIRED, but at this point we don't
  70                          * have the chance to ask the user for a new
  71                          * password. If we return 0 (i.e. success), we will be
  72                          * spinning in the endless for-loop in
  73                          * change_password() in
  74                          * source4/heimdal/lib/krb5/init_creds_pw.c:526ff
  75                          */
  76                         return KRB5KDC_ERR_KEY_EXPIRED;
  77                 }
  78 #elif defined(HAVE_KRB5_GET_PROMPT_TYPES) /* MIT */
  79                 krb5_prompt_type *prompt_types = NULL;
  80
  81                 prompt_types = krb5_get_prompt_types(ctx);
  82                 if (prompt_types != NULL) {
  83                         if (prompt_types[0] == KRB5_PROMPT_TYPE_NEW_PASSWORD &&
  84                             prompt_types[1] == KRB5_PROMPT_TYPE_NEW_PASSWORD_AGAIN) {
  85                                 return KRB5KDC_ERR_KEY_EXP;
  86                         }
  87                 }
  88 #endif
  89         }
  90
  91         memset(prompts[0].reply->data, '\0', prompts[0].reply->length);
  92         if (prompts[0].reply->length > 0) {
  93                 if (data) {
  94                         strncpy((char *)prompts[0].reply->data, (const char *)data,
  95                                 prompts[0].reply->length-1);
  96                         prompts[0].reply->length = strlen((const char *)prompts[0].reply->data);
  97                 } else {
  98                         prompts[0].reply->length = 0;
  99                 }
 100         }
 101         return 0;
 102 }
 103
 104 /*
 105   simulate a kinit, putting the tgt in the given cache location. If cache_name == NULL
 106   place in default cache location.
 107   remus@snapserver.com
 108 */
 109 int kerberos_kinit_password_ext(const char *given_principal,
 110                                 const char *password,
 111                                 int time_offset,
 112                                 time_t *expire_time,
 113                                 time_t *renew_till_time,
 114                                 const char *cache_name,
 115                                 bool request_pac,
 116                                 bool add_netbios_addr,
 117                                 time_t renewable_time,
 118                                 TALLOC_CTX *mem_ctx,
 119                                 char **_canon_principal,
 120                                 char **_canon_realm,
 121                                 NTSTATUS *ntstatus)
 122 {
 123         TALLOC_CTX *frame = talloc_stackframe();
 124         krb5_context ctx = NULL;
 125         krb5_error_code code = 0;
 126         krb5_ccache cc = NULL;
 127         krb5_principal me = NULL;
 128         krb5_principal canon_princ = NULL;
 129         krb5_creds my_creds;
 130         krb5_get_init_creds_opt *opt = NULL;
 131         smb_krb5_addresses *addr = NULL;
 132         char *canon_principal = NULL;
 133         char *canon_realm = NULL;
 134
 135         ZERO_STRUCT(my_creds);
 136
 137         code = smb_krb5_init_context_common(&ctx);
 138         if (code != 0) {
 139                 DBG_ERR("kerberos init context failed (%s)\n",
 140                         error_message(code));
 141                 TALLOC_FREE(frame);
 142                 return code;
 143         }
 144
 145         if (time_offset != 0) {
 146                 krb5_set_real_time(ctx, time(NULL) + time_offset, 0);
 147         }
 148
 149         DBG_DEBUG("as %s using [%s] as ccache and config [%s]\n",
 150                   given_principal,
 151                   cache_name ? cache_name: krb5_cc_default_name(ctx),
 152                   getenv("KRB5_CONFIG"));
 153
 154         if ((code = krb5_cc_resolve(ctx, cache_name ? cache_name : krb5_cc_default_name(ctx), &cc))) {
 155                 goto out;
 156         }
 157
 158         if ((code = smb_krb5_parse_name(ctx, given_principal, &me))) {
 159                 goto out;
 160         }
 161
 162         if ((code = krb5_get_init_creds_opt_alloc(ctx, &opt))) {
 163                 goto out;
 164         }
 165
 166         krb5_get_init_creds_opt_set_renew_life(opt, renewable_time);
 167         krb5_get_init_creds_opt_set_forwardable(opt, True);
 168
 169         /* Turn on canonicalization for lower case realm support */
 170 #ifndef SAMBA4_USES_HEIMDAL /* MIT */
 171         krb5_get_init_creds_opt_set_canonicalize(opt, true);
 172 #endif /* MIT */
 173 #if 0
 174         /* insane testing */
 175         krb5_get_init_creds_opt_set_tkt_life(opt, 60);
 176 #endif
 177
 178 #ifdef HAVE_KRB5_GET_INIT_CREDS_OPT_SET_PAC_REQUEST
 179         if (request_pac) {
 180                 if ((code = krb5_get_init_creds_opt_set_pac_request(ctx, opt, (krb5_boolean)request_pac))) {
 181                         goto out;
 182                 }
 183         }
 184 #endif
 185         if (add_netbios_addr) {
 186                 if ((code = smb_krb5_gen_netbios_krb5_address(&addr,
 187                                                         lp_netbios_name()))) {
 188                         goto out;
 189                 }
 190                 krb5_get_init_creds_opt_set_address_list(opt, addr->addrs);
 191         }
 192
 193         if ((code = krb5_get_init_creds_password(ctx, &my_creds, me, discard_const_p(char,password),
 194                                                  kerb_prompter, discard_const_p(char, password),
 195                                                  0, NULL, opt))) {
 196                 goto out;
 197         }
 198
 199 #ifndef SAMBA4_USES_HEIMDAL /* MIT */
 200         canon_princ = my_creds.client;
 201 #else
 202         canon_princ = me;
 203 #endif /* MIT */
 204
 205         code = smb_krb5_unparse_name(frame,
 206                                      ctx,
 207                                      canon_princ,
 208                                      &canon_principal);
 209         if (code != 0) {
 210                 goto out;
 211         }
 212
 213         DBG_DEBUG("%s mapped to %s\n", given_principal, canon_principal);
 214
 215         canon_realm = smb_krb5_principal_get_realm(frame, ctx, canon_princ);
 216         if (canon_realm == NULL) {
 217                 code = ENOMEM;
 218                 goto out;
 219         }
 220
 221         if ((code = krb5_cc_initialize(ctx, cc, canon_princ))) {
 222                 goto out;
 223         }
 224
 225         if ((code = krb5_cc_store_cred(ctx, cc, &my_creds))) {
 226                 goto out;
 227         }
 228
 229         if (expire_time) {
 230                 *expire_time = (time_t) my_creds.times.endtime;
 231         }
 232
 233         if (renew_till_time) {
 234                 *renew_till_time = (time_t) my_creds.times.renew_till;
 235         }
 236
 237         if (_canon_principal != NULL) {
 238                 *_canon_principal = talloc_move(mem_ctx, &canon_principal);
 239         }
 240         if (_canon_realm != NULL) {
 241                 *_canon_realm = talloc_move(mem_ctx, &canon_realm);
 242         }
 243  out:
 244         if (ntstatus) {
 245                 /* fast path */
 246                 if (code == 0) {
 247                         *ntstatus = NT_STATUS_OK;
 248                         goto cleanup;
 249                 }
 250
 251                 /* fall back to self-made-mapping */
 252                 *ntstatus = krb5_to_nt_status(code);
 253         }
 254
 255  cleanup:
 256         krb5_free_cred_contents(ctx, &my_creds);
 257         if (me) {
 258                 krb5_free_principal(ctx, me);
 259         }
 260         if (addr) {
 261                 smb_krb5_free_addresses(ctx, addr);
 262         }
 263         if (opt) {
 264                 krb5_get_init_creds_opt_free(ctx, opt);
 265         }
 266         if (cc) {
 267                 krb5_cc_close(ctx, cc);
 268         }
 269         if (ctx) {
 270                 krb5_free_context(ctx);
 271         }
 272         TALLOC_FREE(frame);
 273         return code;
 274 }
 275
 276 int ads_kdestroy(const char *cc_name)
 277 {
 278         krb5_error_code code;
 279         krb5_context ctx = NULL;
 280         krb5_ccache cc = NULL;
 281
 282         code = smb_krb5_init_context_common(&ctx);
 283         if (code != 0) {
 284                 DBG_ERR("kerberos init context failed (%s)\n",
 285                         error_message(code));
 286                 return code;
 287         }
 288
 289         if (!cc_name) {
 290                 if ((code = krb5_cc_default(ctx, &cc))) {
 291                         krb5_free_context(ctx);
 292                         return code;
 293                 }
 294         } else {
 295                 if ((code = krb5_cc_resolve(ctx, cc_name, &cc))) {
 296                         DEBUG(3, ("ads_kdestroy: krb5_cc_resolve failed: %s\n",
 297                                   error_message(code)));
 298                         krb5_free_context(ctx);
 299                         return code;
 300                 }
 301         }
 302
 303         if ((code = krb5_cc_destroy (ctx, cc))) {
 304                 DEBUG(3, ("ads_kdestroy: krb5_cc_destroy failed: %s\n",
 305                         error_message(code)));
 306         }
 307
 308         krb5_free_context (ctx);
 309         return code;
 310 }
 311
 312 int create_kerberos_key_from_string(krb5_context context,
 313                                         krb5_principal host_princ,
 314                                         krb5_principal salt_princ,
 315                                         krb5_data *password,
 316                                         krb5_keyblock *key,
 317                                         krb5_enctype enctype,
 318                                         bool no_salt)
 319 {
 320         int ret;
 321         /*
 322          * Check if we've determined that the KDC is salting keys for this
 323          * principal/enctype in a non-obvious way.  If it is, try to match
 324          * its behavior.
 325          */
 326         if (no_salt) {
 327                 KRB5_KEY_DATA(key) = (KRB5_KEY_DATA_CAST *)SMB_MALLOC(password->length);
 328                 if (!KRB5_KEY_DATA(key)) {
 329                         return ENOMEM;
 330                 }
 331                 memcpy(KRB5_KEY_DATA(key), password->data, password->length);
 332                 KRB5_KEY_LENGTH(key) = password->length;
 333                 KRB5_KEY_TYPE(key) = enctype;
 334                 return 0;
 335         }
 336         ret = smb_krb5_create_key_from_string(context,
 337                                               salt_princ ? salt_princ : host_princ,
 338                                               NULL,
 339                                               password,
 340                                               enctype,
 341                                               key);
 342         return ret;
 343 }
 344
 345 /************************************************************************
 346 ************************************************************************/
 347
 348 int kerberos_kinit_password(const char *principal,
 349                             const char *password,
 350                             int time_offset,
 351                             const char *cache_name)
 352 {
 353         return kerberos_kinit_password_ext(principal,
 354                                            password,
 355                                            time_offset,
 356                                            0,
 357                                            0,
 358                                            cache_name,
 359                                            False,
 360                                            False,
 361                                            0,
 362                                            NULL,
 363                                            NULL,
 364                                            NULL,
 365                                            NULL);
 366 }
 367
 368 /************************************************************************
 369 ************************************************************************/
 370
 371 /************************************************************************
 372  Create a string list of available kdc's, possibly searching by sitename.
 373  Does DNS queries.
 374
 375  If "sitename" is given, the DC's in that site are listed first.
 376
 377 ************************************************************************/
 378
 379 static void add_sockaddr_unique(struct sockaddr_storage *addrs, size_t *num_addrs,
 380                                 const struct sockaddr_storage *addr)
 381 {
 382         size_t i;
 383
 384         for (i=0; i<*num_addrs; i++) {
 385                 if (sockaddr_equal((const struct sockaddr *)&addrs[i],
 386                                    (const struct sockaddr *)addr)) {
 387                         return;
 388                 }
 389         }
 390         addrs[i] = *addr;
 391         *num_addrs += 1;
 392 }
 393
 394 /* print_canonical_sockaddr prints an ipv6 addr in the form of
 395 * [ipv6.addr]. This string, when put in a generated krb5.conf file is not
 396 * always properly dealt with by some older krb5 libraries. Adding the hard-coded
 397 * portnumber workarounds the issue. - gd */
 398
 399 static char *print_canonical_sockaddr_with_port(TALLOC_CTX *mem_ctx,
 400                                                 const struct sockaddr_storage *pss)
 401 {
 402         char *str = NULL;
 403
 404         str = print_canonical_sockaddr(mem_ctx, pss);
 405         if (str == NULL) {
 406                 return NULL;
 407         }
 408
 409         if (pss->ss_family != AF_INET6) {
 410                 return str;
 411         }
 412
 413 #if defined(HAVE_IPV6)
 414         str = talloc_asprintf_append(str, ":88");
 415 #endif
 416         return str;
 417 }
 418
 419 static char *get_kdc_ip_string(char *mem_ctx,
 420                 const char *realm,
 421                 const char *sitename,
 422                 const struct sockaddr_storage *pss)
 423 {
 424         TALLOC_CTX *frame = talloc_stackframe();
 425         size_t i;
 426         struct ip_service *ip_srv_site = NULL;
 427         struct ip_service *ip_srv_nonsite = NULL;
 428         int count_site = 0;
 429         int count_nonsite;
 430         size_t num_dcs;
 431         struct sockaddr_storage *dc_addrs;
 432         struct tsocket_address **dc_addrs2 = NULL;
 433         const struct tsocket_address * const *dc_addrs3 = NULL;
 434         char *result = NULL;
 435         struct netlogon_samlogon_response **responses = NULL;
 436         NTSTATUS status;
 437         char *kdc_str = talloc_asprintf(mem_ctx, "%s\t\tkdc = %s\n", "",
 438                                         print_canonical_sockaddr_with_port(mem_ctx, pss));
 439
 440         if (kdc_str == NULL) {
 441                 TALLOC_FREE(frame);
 442                 return NULL;
 443         }
 444
 445         /*
 446          * First get the KDC's only in this site, the rest will be
 447          * appended later
 448          */
 449
 450         if (sitename) {
 451                 get_kdc_list(realm, sitename, &ip_srv_site, &count_site);
 452                 DEBUG(10, ("got %d addresses from site %s search\n", count_site,
 453                            sitename));
 454         }
 455
 456         /* Get all KDC's. */
 457
 458         get_kdc_list(realm, NULL, &ip_srv_nonsite, &count_nonsite);
 459         DEBUG(10, ("got %d addresses from site-less search\n", count_nonsite));
 460
 461         dc_addrs = talloc_array(talloc_tos(), struct sockaddr_storage,
 462                                 count_site + count_nonsite);
 463         if (dc_addrs == NULL) {
 464                 goto out;
 465         }
 466
 467         num_dcs = 0;
 468
 469         for (i = 0; i < count_site; i++) {
 470                 if (!sockaddr_equal(
 471                         (const struct sockaddr *)pss,
 472                         (const struct sockaddr *)&ip_srv_site[i].ss)) {
 473                         add_sockaddr_unique(dc_addrs, &num_dcs,
 474                                             &ip_srv_site[i].ss);
 475                 }
 476         }
 477
 478         for (i = 0; i < count_nonsite; i++) {
 479                 if (!sockaddr_equal(
 480                         (const struct sockaddr *)pss,
 481                         (const struct sockaddr *)&ip_srv_nonsite[i].ss)) {
 482                         add_sockaddr_unique(dc_addrs, &num_dcs,
 483                                             &ip_srv_nonsite[i].ss);
 484                 }
 485         }
 486
 487         dc_addrs2 = talloc_zero_array(talloc_tos(),
 488                                       struct tsocket_address *,
 489                                       num_dcs);
 490
 491         DBG_DEBUG("%zu additional KDCs to test\n", num_dcs);
 492         if (num_dcs == 0) {
 493                 goto out;
 494         }
 495         if (dc_addrs2 == NULL) {
 496                 goto out;
 497         }
 498
 499         for (i=0; i<num_dcs; i++) {
 500                 char addr[INET6_ADDRSTRLEN];
 501                 int ret;
 502
 503                 print_sockaddr(addr, sizeof(addr), &dc_addrs[i]);
 504
 505                 ret = tsocket_address_inet_from_strings(dc_addrs2, "ip",
 506                                                         addr, LDAP_PORT,
 507                                                         &dc_addrs2[i]);
 508                 if (ret != 0) {
 509                         status = map_nt_error_from_unix(errno);
 510                         DEBUG(2,("Failed to create tsocket_address for %s - %s\n",
 511                                  addr, nt_errstr(status)));
 512                         goto out;
 513                 }
 514         }
 515
 516         dc_addrs3 = (const struct tsocket_address * const *)dc_addrs2;
 517
 518         status = cldap_multi_netlogon(talloc_tos(),
 519                         dc_addrs3, num_dcs,
 520                         realm, lp_netbios_name(),
 521                         NETLOGON_NT_VERSION_5 | NETLOGON_NT_VERSION_5EX,
 522                         MIN(num_dcs, 3), timeval_current_ofs(3, 0), &responses);
 523         TALLOC_FREE(dc_addrs2);
 524         dc_addrs3 = NULL;
 525
 526         if (!NT_STATUS_IS_OK(status)) {
 527                 DEBUG(10,("get_kdc_ip_string: cldap_multi_netlogon failed: "
 528                           "%s\n", nt_errstr(status)));
 529                 goto out;
 530         }
 531
 532         for (i=0; i<num_dcs; i++) {
 533                 char *new_kdc_str;
 534
 535                 if (responses[i] == NULL) {
 536                         continue;
 537                 }
 538
 539                 /* Append to the string - inefficient but not done often. */
 540                 new_kdc_str = talloc_asprintf(mem_ctx, "%s\t\tkdc = %s\n",
 541                                               kdc_str,
 542                                               print_canonical_sockaddr_with_port(mem_ctx, &dc_addrs[i]));
 543                 if (new_kdc_str == NULL) {
 544                         goto out;
 545                 }
 546                 TALLOC_FREE(kdc_str);
 547                 kdc_str = new_kdc_str;
 548         }
 549
 550 out:
 551         DEBUG(10, ("get_kdc_ip_string: Returning %s\n", kdc_str));
 552
 553         result = kdc_str;
 554         SAFE_FREE(ip_srv_site);
 555         SAFE_FREE(ip_srv_nonsite);
 556         TALLOC_FREE(frame);
 557         return result;
 558 }
 559
 560 /************************************************************************
 561  Create  a specific krb5.conf file in the private directory pointing
 562  at a specific kdc for a realm. Keyed off domain name. Sets
 563  KRB5_CONFIG environment variable to point to this file. Must be
 564  run as root or will fail (which is a good thing :-).
 565 ************************************************************************/
 566
 567 #if !defined(SAMBA4_USES_HEIMDAL) /* MIT version */
 568 static char *get_enctypes(TALLOC_CTX *mem_ctx)
 569 {
 570         char *aes_enctypes = NULL;
 571         const char *legacy_enctypes = "";
 572         char *enctypes = NULL;
 573
 574         aes_enctypes = talloc_strdup(mem_ctx, "");
 575         if (aes_enctypes == NULL) {
 576                 goto done;
 577         }
 578
 579         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 580             lp_kerberos_encryption_types() == KERBEROS_ETYPES_STRONG) {
 581 #ifdef HAVE_ENCTYPE_AES256_CTS_HMAC_SHA1_96
 582                 aes_enctypes = talloc_asprintf_append(
 583                     aes_enctypes, "%s", "aes256-cts-hmac-sha1-96 ");
 584                 if (aes_enctypes == NULL) {
 585                         goto done;
 586                 }
 587 #endif
 588 #ifdef HAVE_ENCTYPE_AES128_CTS_HMAC_SHA1_96
 589                 aes_enctypes = talloc_asprintf_append(
 590                     aes_enctypes, "%s", "aes128-cts-hmac-sha1-96");
 591                 if (aes_enctypes == NULL) {
 592                         goto done;
 593                 }
 594 #endif
 595         }
 596
 597         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 598             lp_kerberos_encryption_types() == KERBEROS_ETYPES_LEGACY) {
 599                 legacy_enctypes = "RC4-HMAC DES-CBC-CRC DES-CBC-MD5";
 600         }
 601
 602         enctypes =
 603             talloc_asprintf(mem_ctx, "\tdefault_tgs_enctypes = %s %s\n"
 604                                      "\tdefault_tkt_enctypes = %s %s\n"
 605                                      "\tpreferred_enctypes = %s %s\n",
 606                             aes_enctypes, legacy_enctypes, aes_enctypes,
 607                             legacy_enctypes, aes_enctypes, legacy_enctypes);
 608 done:
 609         TALLOC_FREE(aes_enctypes);
 610         return enctypes;
 611 }
 612 #else /* Heimdal version */
 613 static char *get_enctypes(TALLOC_CTX *mem_ctx)
 614 {
 615         const char *aes_enctypes = "";
 616         const char *legacy_enctypes = "";
 617         char *enctypes = NULL;
 618
 619         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 620             lp_kerberos_encryption_types() == KERBEROS_ETYPES_STRONG) {
 621                 aes_enctypes =
 622                     "aes256-cts-hmac-sha1-96 aes128-cts-hmac-sha1-96";
 623         }
 624
 625         if (lp_kerberos_encryption_types() == KERBEROS_ETYPES_ALL ||
 626             lp_kerberos_encryption_types() == KERBEROS_ETYPES_LEGACY) {
 627                 legacy_enctypes = "arcfour-hmac-md5 des-cbc-crc des-cbc-md5";
 628         }
 629
 630         enctypes = talloc_asprintf(mem_ctx, "\tdefault_etypes = %s %s\n",
 631                                    aes_enctypes, legacy_enctypes);
 632
 633         return enctypes;
 634 }
 635 #endif
 636
 637 bool create_local_private_krb5_conf_for_domain(const char *realm,
 638                                                 const char *domain,
 639                                                 const char *sitename,
 640                                                 const struct sockaddr_storage *pss)
 641 {
 642         char *dname;
 643         char *tmpname = NULL;
 644         char *fname = NULL;
 645         char *file_contents = NULL;
 646         char *kdc_ip_string = NULL;
 647         size_t flen = 0;
 648         ssize_t ret;
 649         int fd;
 650         char *realm_upper = NULL;
 651         bool result = false;
 652         char *enctypes = NULL;
 653         const char *include_system_krb5 = "";
 654         mode_t mask;
 655
 656         if (!lp_create_krb5_conf()) {
 657                 return false;
 658         }
 659
 660         if (realm == NULL) {
 661                 DEBUG(0, ("No realm has been specified! Do you really want to "
 662                           "join an Active Directory server?\n"));
 663                 return false;
 664         }
 665
 666         if (domain == NULL || pss == NULL) {
 667                 return false;
 668         }
 669
 670         dname = lock_path(talloc_tos(), "smb_krb5");
 671         if (!dname) {
 672                 return false;
 673         }
 674         if ((mkdir(dname, 0755)==-1) && (errno != EEXIST)) {
 675                 DEBUG(0,("create_local_private_krb5_conf_for_domain: "
 676                         "failed to create directory %s. Error was %s\n",
 677                         dname, strerror(errno) ));
 678                 goto done;
 679         }
 680
 681         tmpname = lock_path(talloc_tos(), "smb_tmp_krb5.XXXXXX");
 682         if (!tmpname) {
 683                 goto done;
 684         }
 685
 686         fname = talloc_asprintf(dname, "%s/krb5.conf.%s", dname, domain);
 687         if (!fname) {
 688                 goto done;
 689         }
 690
 691         DEBUG(10,("create_local_private_krb5_conf_for_domain: fname = %s, realm = %s, domain = %s\n",
 692                 fname, realm, domain ));
 693
 694         realm_upper = talloc_strdup(fname, realm);
 695         if (!strupper_m(realm_upper)) {
 696                 goto done;
 697         }
 698
 699         kdc_ip_string = get_kdc_ip_string(dname, realm, sitename, pss);
 700         if (!kdc_ip_string) {
 701                 goto done;
 702         }
 703
 704         enctypes = get_enctypes(fname);
 705         if (enctypes == NULL) {
 706                 goto done;
 707         }
 708
 709 #if !defined(SAMBA4_USES_HEIMDAL)
 710         if (lp_include_system_krb5_conf()) {
 711                 include_system_krb5 = "include /etc/krb5.conf";
 712         }
 713 #endif
 714
 715         /*
 716          * We are setting 'dns_lookup_kdc' to true, because we want to lookup
 717          * KDCs which are not configured via DNS SRV records, eg. if we do:
 718          *
 719          *     net ads join -Uadmin@otherdomain
 720          */
 721         file_contents =
 722             talloc_asprintf(fname,
 723                             "[libdefaults]\n"
 724                             "\tdefault_realm = %s\n"
 725                             "%s"
 726                             "\tdns_lookup_realm = false\n"
 727                             "\tdns_lookup_kdc = true\n\n"
 728                             "[realms]\n\t%s = {\n"
 729                             "%s\t}\n"
 730                             "%s\n",
 731                             realm_upper,
 732                             enctypes,
 733                             realm_upper,
 734                             kdc_ip_string,
 735                             include_system_krb5);
 736
 737         if (!file_contents) {
 738                 goto done;
 739         }
 740
 741         flen = strlen(file_contents);
 742
 743         mask = umask(S_IRWXO | S_IRWXG);
 744         fd = mkstemp(tmpname);
 745         umask(mask);
 746         if (fd == -1) {
 747                 DEBUG(0,("create_local_private_krb5_conf_for_domain: smb_mkstemp failed,"
 748                         " for file %s. Errno %s\n",
 749                         tmpname, strerror(errno) ));
 750                 goto done;
 751         }
 752
 753         if (fchmod(fd, 0644)==-1) {
 754                 DEBUG(0,("create_local_private_krb5_conf_for_domain: fchmod failed for %s."
 755                         " Errno %s\n",
 756                         tmpname, strerror(errno) ));
 757                 unlink(tmpname);
 758                 close(fd);
 759                 goto done;
 760         }
 761
 762         ret = write(fd, file_contents, flen);
 763         if (flen != ret) {
 764                 DEBUG(0,("create_local_private_krb5_conf_for_domain: write failed,"
 765                         " returned %d (should be %u). Errno %s\n",
 766                         (int)ret, (unsigned int)flen, strerror(errno) ));
 767                 unlink(tmpname);
 768                 close(fd);
 769                 goto done;
 770         }
 771         if (close(fd)==-1) {
 772                 DEBUG(0,("create_local_private_krb5_conf_for_domain: close failed."
 773                         " Errno %s\n", strerror(errno) ));
 774                 unlink(tmpname);
 775                 goto done;
 776         }
 777
 778         if (rename(tmpname, fname) == -1) {
 779                 DEBUG(0,("create_local_private_krb5_conf_for_domain: rename "
 780                         "of %s to %s failed. Errno %s\n",
 781                         tmpname, fname, strerror(errno) ));
 782                 unlink(tmpname);
 783                 goto done;
 784         }
 785
 786         DEBUG(5,("create_local_private_krb5_conf_for_domain: wrote "
 787                 "file %s with realm %s KDC list = %s\n",
 788                 fname, realm_upper, kdc_ip_string));
 789
 790         /* Set the environment variable to this file. */
 791         setenv("KRB5_CONFIG", fname, 1);
 792
 793         result = true;
 794
 795 #if defined(OVERWRITE_SYSTEM_KRB5_CONF)
 796
 797 #define SYSTEM_KRB5_CONF_PATH "/etc/krb5.conf"
 798         /* Insanity, sheer insanity..... */
 799
 800         if (strequal(realm, lp_realm())) {
 801                 SMB_STRUCT_STAT sbuf;
 802
 803                 if (sys_lstat(SYSTEM_KRB5_CONF_PATH, &sbuf, false) == 0) {
 804                         if (S_ISLNK(sbuf.st_ex_mode) && sbuf.st_ex_size) {
 805                                 int lret;
 806                                 size_t alloc_size = sbuf.st_ex_size + 1;
 807                                 char *linkpath = talloc_array(talloc_tos(), char,
 808                                                 alloc_size);
 809                                 if (!linkpath) {
 810                                         goto done;
 811                                 }
 812                                 lret = readlink(SYSTEM_KRB5_CONF_PATH, linkpath,
 813                                                 alloc_size - 1);
 814                                 if (lret == -1) {
 815                                         TALLOC_FREE(linkpath);
 816                                         goto done;
 817                                 }
 818                                 linkpath[lret] = '\0';
 819
 820                                 if (strcmp(linkpath, fname) == 0) {
 821                                         /* Symlink already exists. */
 822                                         TALLOC_FREE(linkpath);
 823                                         goto done;
 824                                 }
 825                                 TALLOC_FREE(linkpath);
 826                         }
 827                 }
 828
 829                 /* Try and replace with a symlink. */
 830                 if (symlink(fname, SYSTEM_KRB5_CONF_PATH) == -1) {
 831                         const char *newpath = SYSTEM_KRB5_CONF_PATH ".saved";
 832                         if (errno != EEXIST) {
 833                                 DEBUG(0,("create_local_private_krb5_conf_for_domain: symlink "
 834                                         "of %s to %s failed. Errno %s\n",
 835                                         fname, SYSTEM_KRB5_CONF_PATH, strerror(errno) ));
 836                                 goto done; /* Not a fatal error. */
 837                         }
 838
 839                         /* Yes, this is a race conditon... too bad. */
 840                         if (rename(SYSTEM_KRB5_CONF_PATH, newpath) == -1) {
 841                                 DEBUG(0,("create_local_private_krb5_conf_for_domain: rename "
 842                                         "of %s to %s failed. Errno %s\n",
 843                                         SYSTEM_KRB5_CONF_PATH, newpath,
 844                                         strerror(errno) ));
 845                                 goto done; /* Not a fatal error. */
 846                         }
 847
 848                         if (symlink(fname, SYSTEM_KRB5_CONF_PATH) == -1) {
 849                                 DEBUG(0,("create_local_private_krb5_conf_for_domain: "
 850                                         "forced symlink of %s to /etc/krb5.conf failed. Errno %s\n",
 851                                         fname, strerror(errno) ));
 852                                 goto done; /* Not a fatal error. */
 853                         }
 854                 }
 855         }
 856 #endif
 857
 858 done:
 859         TALLOC_FREE(tmpname);
 860         TALLOC_FREE(dname);
 861
 862         return result;
 863 }
 864 #endif