source3/libads/kerberos_keytab.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    kerberos keytab utility library
   4    Copyright (C) Andrew Tridgell 2001
   5    Copyright (C) Remus Koos 2001
   6    Copyright (C) Luke Howard 2003
   7    Copyright (C) Jim McDonough (jmcd@us.ibm.com) 2003
   8    Copyright (C) Guenther Deschner 2003
   9    Copyright (C) Rakesh Patel 2004
  10    Copyright (C) Dan Perry 2004
  11    Copyright (C) Jeremy Allison 2004
  12
  13    This program is free software; you can redistribute it and/or modify
  14    it under the terms of the GNU General Public License as published by
  15    the Free Software Foundation; either version 2 of the License, or
  16    (at your option) any later version.
  17
  18    This program is distributed in the hope that it will be useful,
  19    but WITHOUT ANY WARRANTY; without even the implied warranty of
  20    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21    GNU General Public License for more details.
  22
  23    You should have received a copy of the GNU General Public License
  24    along with this program; if not, write to the Free Software
  25    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  26 */
  27
  28 #include "includes.h"
  29
  30 #ifdef HAVE_KRB5
  31
  32 /**********************************************************************
  33  Converts a name to a fully qalified domain name.
  34 ***********************************************************************/
  35
  36 void name_to_fqdn(fstring fqdn, const char *name)
  37 {
  38         struct hostent *hp = sys_gethostbyname(name);
  39         if ( hp && hp->h_name && *hp->h_name ) {
  40                 DEBUG(10,("name_to_fqdn: lookup for %s -> %s.\n", name, hp->h_name));
  41                 fstrcpy(fqdn,hp->h_name);
  42         } else {
  43                 DEBUG(10,("name_to_fqdn: lookup for %s failed.\n", name));
  44                 fstrcpy(fqdn, name);
  45         }
  46 }
  47
  48 /**********************************************************************
  49   Adds a single service principal, i.e. 'host' to the system keytab
  50 ***********************************************************************/
  51
  52 int ads_keytab_add_entry(const char *srvPrinc, ADS_STRUCT *ads)
  53 {
  54         krb5_error_code ret = 0;
  55         krb5_context context = NULL;
  56         krb5_keytab keytab = NULL;
  57         krb5_kt_cursor cursor = NULL;
  58         krb5_keytab_entry kt_entry;
  59         krb5_principal princ = NULL;
  60         krb5_data password;
  61         krb5_enctype *enctypes = NULL;
  62         krb5_kvno kvno;
  63         krb5_keyblock *key = NULL;
  64
  65         char *principal = NULL;
  66         char *princ_s = NULL;
  67         char *password_s = NULL;
  68         char keytab_name[MAX_KEYTAB_NAME_LEN];          /* This MAX_NAME_LEN is a constant defined in krb5.h */
  69         fstring my_fqdn;
  70         int i;
  71         char *ktprinc = NULL;
  72
  73         ZERO_STRUCT(kt_entry);
  74         initialize_krb5_error_table();
  75         ret = krb5_init_context(&context);
  76         if (ret) {
  77                 DEBUG(1,("ads_keytab_add_entry: could not krb5_init_context: %s\n",error_message(ret)));
  78                 return -1;
  79         }
  80 #ifdef HAVE_WRFILE_KEYTAB       /* MIT */
  81         keytab_name[0] = 'W';
  82         keytab_name[1] = 'R';
  83         ret = krb5_kt_default_name(context, (char *) &keytab_name[2], MAX_KEYTAB_NAME_LEN - 4);
  84 #else                           /* Heimdal */
  85         ret = krb5_kt_default_name(context, (char *) &keytab_name[0], MAX_KEYTAB_NAME_LEN - 2);
  86 #endif
  87         if (ret) {
  88                 DEBUG(1,("ads_keytab_add_entry: krb5_kt_default_name failed (%s)\n", error_message(ret)));
  89                 goto out;
  90         }
  91         DEBUG(2,("ads_keytab_add_entry: Using default system keytab: %s\n", (char *) &keytab_name));
  92         ret = krb5_kt_resolve(context, (char *) &keytab_name, &keytab);
  93         if (ret) {
  94                 DEBUG(1,("ads_keytab_add_entry: krb5_kt_resolve failed (%s)\n", error_message(ret)));
  95                 goto out;
  96         }
  97
  98         ret = get_kerberos_allowed_etypes(context,&enctypes);
  99         if (ret) {
 100                 DEBUG(1,("ads_keytab_add_entry: get_kerberos_allowed_etypes failed (%s)\n",error_message(ret)));
 101                 goto out;
 102         }
 103
 104         /* retrieve the password */
 105         if (!secrets_init()) {
 106                 DEBUG(1,("ads_keytab_add_entry: secrets_init failed\n"));
 107                 ret = -1;
 108                 goto out;
 109         }
 110         password_s = secrets_fetch_machine_password(lp_workgroup(), NULL, NULL);
 111         if (!password_s) {
 112                 DEBUG(1,("ads_keytab_add_entry: failed to fetch machine password\n"));
 113                 ret = -1;
 114                 goto out;
 115         }
 116         password.data = password_s;
 117         password.length = strlen(password_s);
 118
 119         /* Construct our principal */
 120         name_to_fqdn(my_fqdn, global_myname());
 121         strlower_m(my_fqdn);
 122         asprintf(&princ_s, "%s/%s@%s", srvPrinc, my_fqdn, lp_realm());
 123
 124         ret = krb5_parse_name(context, princ_s, &princ);
 125         if (ret) {
 126                 DEBUG(1,("ads_keytab_add_entry: krb5_parse_name(%s) failed (%s)\n", princ_s, error_message(ret)));
 127                 goto out;
 128         }
 129
 130         kvno = (krb5_kvno) ads_get_kvno(ads, global_myname());
 131         if (kvno == -1) {       /* -1 indicates failure, everything else is OK */
 132                 DEBUG(1,("ads_keytab_add_entry: ads_get_kvno failed to determine the system's kvno.\n"));
 133                 ret = -1;
 134                 goto out;
 135         }
 136
 137         /* Seek and delete old keytab entries */
 138         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 139         if (ret != KRB5_KT_END && ret != ENOENT ) {
 140                 DEBUG(3,("ads_keytab_add_entry: Will try to delete old keytab entries\n"));
 141                 while(!krb5_kt_next_entry(context, keytab, &kt_entry, &cursor)) {
 142
 143                         ret = krb5_unparse_name(context, entry.principal, &ktprinc);
 144                         if (ret) {
 145                                 DEBUG(1,("ads_keytab_add_entry: krb5_unparse_name failed (%s)\n", error_message(ret)));
 146                                 goto out;
 147                         }
 148
 149                         /*---------------------------------------------------------------------------
 150                          * Save the entries with kvno - 1.   This is what microsoft does
 151                          * to allow people with existing sessions that have kvno - 1 to still
 152                          * work.   Otherwise, when the password for the machine changes, all
 153                          * kerberizied sessions will 'break' until either the client reboots or
 154                          * the client's session key expires and they get a new session ticket
 155                          * with the new kvno.
 156                          */
 157
 158                         HERE
 159
 160 #ifdef HAVE_KRB5_KT_COMPARE
 161                         if (krb5_kt_compare(context, &kt_entry, princ, 0, 0) == True && kt_entry.vno != kvno - 1) {
 162 #else
 163                         if (strcmp(ktprinc, princ_s) == 0 && kt_entry.vno != kvno - 1) {
 164 #endif
 165                                 SAFE_FREE(ktprinc);
 166                                 DEBUG(1,("Found old entry for principal: %s (kvno %d) - trying to remove it.\n",
 167                                         princ_s, entry.vno));
 168                                 ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 169                                 if (ret) {
 170                                         DEBUG(1,("krb5_kt_end_seq_get() failed (%s)\n", error_message(ret)));
 171                                         goto out;
 172                                 }
 173                                 ret = krb5_kt_remove_entry(context, keytab, &entry);
 174                                 if (ret) {
 175                                         DEBUG(1,("krb5_kt_remove_entry failed (%s)\n", error_message(ret)));
 176                                         goto out;
 177                                 }
 178                                 ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 179                                 if (ret) {
 180                                         DEBUG(1,("krb5_kt_start_seq failed (%s)\n", error_message(ret)));
 181                                         goto out;
 182                                 }
 183                                 ret = krb5_kt_free_entry(context, &entry);
 184                                 if (ret) {
 185                                         DEBUG(1,("krb5_kt_remove_entry failed (%s)\n", error_message(ret)));
 186                                         goto out;
 187                                 }
 188                                 continue;
 189                         } else {
 190                                 SAFE_FREE(ktprinc);
 191                         }
 192
 193                         ret = krb5_kt_free_entry(context, &entry);
 194                         if (ret) {
 195                                 DEBUG(1,("krb5_kt_free_entry failed (%s)\n", error_message(ret)));
 196                                 goto out;
 197                         }
 198                 }
 199
 200                 ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 201                 if (ret) {
 202                         DEBUG(1,("krb5_kt_end_seq_get failed (%s)\n",error_message(ret)));
 203                         goto out;
 204                 }
 205         }
 206
 207         /* Add keytab entries for all encryption types */
 208         for (i = 0; enctypes[i]; i++) {
 209
 210                 key = (krb5_keyblock *) malloc(sizeof(*key));
 211                 if (!key) {
 212                         DEBUG(1,("Failed to allocate memory to store the keyblock.\n"));
 213                         ret = ENOMEM;
 214                         goto out;
 215                 }
 216
 217                 if (create_kerberos_key_from_string(context, princ, &password, key, enctypes[i])) {
 218                         continue;
 219                 }
 220
 221                 entry.principal = princ;
 222                 entry.vno       = kvno;
 223
 224 #if !defined(HAVE_KRB5_KEYTAB_ENTRY_KEY) && !defined(HAVE_KRB5_KEYTAB_ENTRY_KEYBLOCK)
 225 #error krb5_keytab_entry has no key or keyblock member
 226 #endif
 227 #ifdef HAVE_KRB5_KEYTAB_ENTRY_KEY               /* MIT */
 228                 entry.key = *key;
 229 #endif
 230 #ifdef HAVE_KRB5_KEYTAB_ENTRY_KEYBLOCK          /* Heimdal */
 231                 entry.keyblock = *key;
 232 #endif
 233                 DEBUG(3,("adding keytab entry for (%s) with encryption type (%d) and version (%d)\n",
 234                 princ_s, enctypes[i], entry.vno));
 235                 ret = krb5_kt_add_entry(context, keytab, &entry);
 236                 krb5_free_keyblock(context, key);
 237                 if (ret) {
 238                         DEBUG(1,("adding entry to keytab failed (%s)\n", error_message(ret)));
 239                         krb5_kt_close(context, keytab);
 240                         goto out;
 241                 }
 242         }
 243
 244         /* Update the LDAP with the SPN */
 245         DEBUG(1,("Attempting to add/update '%s'\n", princ_s));
 246         if (!ADS_ERR_OK(ads_add_spn(ads, global_myname(), srvPrinc))) {
 247                 DEBUG(1,("ads_add_spn failed.\n"));
 248                 goto out;
 249         }
 250
 251 out:
 252
 253         SAFE_FREE(principal);
 254         SAFE_FREE(password_s);
 255         SAFE_FREE(princ_s);
 256
 257         {
 258                 krb5_keytab_entry zero_kt_entry;
 259                 ZERO_STRUCT(zero_kt_entry);
 260                 if (memcmp(&zero_kt_entry, &kt_entry, sizeof(krb5_keytab_entry))) {
 261                         krb5_kt_free_entry(context, &kt_entry);
 262                 }
 263         }
 264         if (princ) {
 265                 krb5_free_principal(context, princ);
 266         }
 267         if (enctypes) {
 268                 free_kerberos_etypes(context, enctypes);
 269         }
 270         if (cursor && keytab) {
 271                 krb5_kt_end_seq_get(context, keytab, &cursor);
 272         }
 273         if (keytab) {
 274                 krb5_kt_close(context, keytab);
 275         }
 276         if (context) {
 277                 krb5_free_context(context);
 278         }
 279         return (int)ret;
 280 }
 281
 282
 283 /*
 284   Flushes all entries from the system keytab.
 285 */
 286 int ads_keytab_flush(ADS_STRUCT *ads)
 287 {
 288         krb5_error_code ret;
 289         krb5_context context;
 290         krb5_keytab keytab;
 291         krb5_kt_cursor cursor;
 292         krb5_keytab_entry entry;
 293         krb5_kvno kvno;
 294         char keytab_name[MAX_KEYTAB_NAME_LEN];
 295
 296         initialize_krb5_error_table();
 297         ret = krb5_init_context(&context);
 298         if (ret) {
 299                 DEBUG(1,("could not krb5_init_context: %s\n",error_message(ret)));
 300                 return ret;
 301         }
 302 #ifdef HAVE_WRFILE_KEYTAB
 303         keytab_name[0] = 'W';
 304         keytab_name[1] = 'R';
 305         ret = krb5_kt_default_name(context, (char *) &keytab_name[2], MAX_KEYTAB_NAME_LEN - 4);
 306 #else
 307         ret = krb5_kt_default_name(context, (char *) &keytab_name[0], MAX_KEYTAB_NAME_LEN - 2);
 308 #endif
 309         if (ret) {
 310                 DEBUG(1,("krb5_kt_default failed (%s)\n", error_message(ret)));
 311                 goto out;
 312         }
 313         DEBUG(1,("Using default keytab: %s\n", (char *) &keytab_name));
 314         ret = krb5_kt_resolve(context, (char *) &keytab_name, &keytab);
 315         if (ret) {
 316                 DEBUG(1,("krb5_kt_default failed (%s)\n", error_message(ret)));
 317                 goto out;
 318         }
 319         DEBUG(1,("Using default keytab: %s\n", (char *) &keytab_name));
 320         ret = krb5_kt_resolve(context, (char *) &keytab_name, &keytab);
 321         if (ret) {
 322                 DEBUG(1,("krb5_kt_default failed (%s)\n", error_message(ret)));
 323                 goto out;
 324         }
 325
 326         kvno = (krb5_kvno) ads_get_kvno(ads, global_myname());
 327         if (kvno == -1) {       /* -1 indicates a failure */
 328                 DEBUG(1,("Error determining the system's kvno.\n"));
 329                 goto out;
 330         }
 331
 332         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 333         if (ret != KRB5_KT_END && ret != ENOENT) {
 334                 while (!krb5_kt_next_entry(context, keytab, &entry, &cursor)) {
 335                         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 336                         if (ret) {
 337                                 DEBUG(1,("krb5_kt_end_seq_get() failed (%s)\n",error_message(ret)));
 338                                 goto out;
 339                         }
 340                         ret = krb5_kt_remove_entry(context, keytab, &entry);
 341                         if (ret) {
 342                                 DEBUG(1,("krb5_kt_remove_entry failed (%s)\n",error_message(ret)));
 343                                 goto out;
 344                         }
 345                         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 346                         if (ret) {
 347                                 DEBUG(1,("krb5_kt_start_seq failed (%s)\n",error_message(ret)));
 348                                 goto out;
 349                         }
 350                         ret = krb5_kt_free_entry(context, &entry);
 351                         if (ret) {
 352                                 DEBUG(1,("krb5_kt_remove_entry failed (%s)\n",error_message(ret)));
 353                                 goto out;
 354                         }
 355                 }
 356         }
 357         if (!ADS_ERR_OK(ads_clear_spns(ads, global_myname()))) {
 358                 DEBUG(1,("Error while clearing service principal listings in LDAP.\n"));
 359                 goto out;
 360         }
 361
 362 out:
 363
 364         krb5_kt_close(context, keytab);
 365         return ret;
 366 }
 367
 368
 369 int ads_keytab_create_default(ADS_STRUCT *ads)
 370 {
 371         krb5_error_code ret;
 372         krb5_context context;
 373         krb5_keytab keytab;
 374         krb5_kt_cursor cursor;
 375         krb5_keytab_entry entry;
 376         krb5_kvno kvno;
 377         char *ktprinc;
 378         int i, found = 0;
 379         char **oldEntries;
 380
 381         ret = ads_keytab_add_entry("host", ads);
 382         if (ret) {
 383                 DEBUG(1,("ads_keytab_add_entry failed while adding 'host'.\n"));
 384                 return ret;
 385         }
 386         ret = ads_keytab_add_entry("cifs", ads);
 387         if (ret) {
 388                 DEBUG(1,("ads_keytab_add_entry failed while adding 'cifs'.\n"));
 389                 return ret;
 390         }
 391
 392         kvno = (krb5_kvno) ads_get_kvno(ads, global_myname());
 393         if (kvno == -1) {
 394                 DEBUG(1,("ads_get_kvno failed to determine the system's kvno.\n"));
 395                 return -1;
 396         }
 397
 398         DEBUG(1,("Searching for keytab entries to preserve and update.\n"));
 399         /* Now loop through the keytab and update any other existing entries... */
 400         initialize_krb5_error_table();
 401         ret = krb5_init_context(&context);
 402         if (ret) {
 403                 DEBUG(1,("could not krb5_init_context: %s\n",error_message(ret)));
 404                 return ret;
 405         }
 406         ret = krb5_kt_default(context, &keytab);
 407         if (ret) {
 408                 DEBUG(1,("krb5_kt_default failed (%s)\n",error_message(ret)));
 409                 return ret;
 410         }
 411
 412         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 413         if (ret != KRB5_KT_END && ret != ENOENT ) {
 414                 while ((ret = krb5_kt_next_entry(context, keytab, &entry, &cursor)) == 0) {
 415                         found++;
 416                 }
 417         }
 418
 419         DEBUG(1, ("Found %d entries in the keytab.\n", found));
 420         if (!found) {
 421                 goto done;
 422         }
 423         oldEntries = (char **) malloc(found * sizeof(char *));
 424         if (!oldEntries) {
 425                 DEBUG(1,("Failed to allocate space to store the old keytab entries (malloc failed?).\n"));
 426                 return ENOMEM;
 427         }
 428         memset(oldEntries, 0, found * sizeof(char *));
 429
 430         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 431         if (ret != KRB5_KT_END && ret != ENOENT ) {
 432                 while ((ret = krb5_kt_next_entry(context, keytab, &entry, &cursor)) == 0) {
 433                         if (entry.vno != kvno) {
 434                                 krb5_unparse_name(context, entry.principal, &ktprinc);
 435                                 for (i = 0; *(ktprinc + i); i++) {
 436                                         if (*(ktprinc + i) == '/') {
 437                                                 *(ktprinc + i) = (char) NULL;
 438                                                 break;
 439                                         }
 440                                 }
 441                                 for (i = 0; i < found; i++) {
 442                                         if (!oldEntries[i]) {
 443                                                 oldEntries[i] = ktprinc;
 444                                                 break;
 445                                         }
 446                                         if (!strcmp(oldEntries[i], ktprinc)) {
 447                                                 break;
 448                                         }
 449                                 }
 450                         }
 451                 }
 452                 for (i = 0; oldEntries[i]; i++) {
 453                         ret |= ads_keytab_add_entry(oldEntries[i], ads);
 454                         free(oldEntries[i]);
 455                 }
 456         }
 457         free(oldEntries);
 458
 459 done:
 460
 461         krb5_kt_close(context, keytab);
 462         return ret;
 463 }
 464 #endif /* HAVE_KRB5 */