source3/libnet/libnet_keytab.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    dump the remote SAM using rpc samsync operations
   4
   5    Copyright (C) Guenther Deschner 2008.
   6    Copyright (C) Michael Adam 2008
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 3 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  20 */
  21
  22 #include "includes.h"
  23 #include "smb_krb5.h"
  24 #include "ads.h"
  25 #include "secrets.h"
  26 #include "libnet/libnet_keytab.h"
  27
  28 #ifdef HAVE_KRB5
  29
  30 /****************************************************************
  31 ****************************************************************/
  32
  33 static int keytab_close(struct libnet_keytab_context *ctx)
  34 {
  35         if (!ctx) {
  36                 return 0;
  37         }
  38
  39         if (ctx->keytab && ctx->context) {
  40                 krb5_kt_close(ctx->context, ctx->keytab);
  41         }
  42
  43         if (ctx->context) {
  44                 krb5_free_context(ctx->context);
  45         }
  46
  47         if (ctx->ads) {
  48                 ads_destroy(&ctx->ads);
  49         }
  50
  51         TALLOC_FREE(ctx);
  52
  53         return 0;
  54 }
  55
  56 /****************************************************************
  57 ****************************************************************/
  58
  59 krb5_error_code libnet_keytab_init(TALLOC_CTX *mem_ctx,
  60                                    const char *keytab_name,
  61                                    struct libnet_keytab_context **ctx)
  62 {
  63         krb5_error_code ret = 0;
  64         krb5_context context = NULL;
  65         krb5_keytab keytab = NULL;
  66         const char *keytab_string = NULL;
  67
  68         struct libnet_keytab_context *r;
  69
  70         r = talloc_zero(mem_ctx, struct libnet_keytab_context);
  71         if (!r) {
  72                 return ENOMEM;
  73         }
  74
  75         talloc_set_destructor(r, keytab_close);
  76
  77         ret = smb_krb5_init_context_common(&context);
  78         if (ret) {
  79                 DBG_ERR("kerberos init context failed (%s)\n",
  80                         error_message(ret));
  81                 return ret;
  82         }
  83
  84         ret = smb_krb5_kt_open_relative(context,
  85                                         keytab_name,
  86                                         true, /* write_access */
  87                                         &keytab);
  88         if (ret) {
  89                 DEBUG(1,("keytab_init: smb_krb5_open_keytab failed (%s)\n",
  90                         error_message(ret)));
  91                 krb5_free_context(context);
  92                 return ret;
  93         }
  94
  95         ret = smb_krb5_kt_get_name(mem_ctx, context, keytab, &keytab_string);
  96         if (ret) {
  97                 krb5_kt_close(context, keytab);
  98                 krb5_free_context(context);
  99                 return ret;
 100         }
 101
 102         r->context = context;
 103         r->keytab = keytab;
 104         r->keytab_name = keytab_string;
 105         r->clean_old_entries = false;
 106
 107         *ctx = r;
 108
 109         return 0;
 110 }
 111
 112 /****************************************************************
 113 ****************************************************************/
 114
 115 /**
 116  * Remove all entries that have the given principal, kvno and enctype.
 117  */
 118 static krb5_error_code libnet_keytab_remove_entries(krb5_context context,
 119                                                     krb5_keytab keytab,
 120                                                     const char *principal,
 121                                                     int kvno,
 122                                                     const krb5_enctype enctype,
 123                                                     bool ignore_kvno)
 124 {
 125         krb5_error_code ret;
 126         krb5_kt_cursor cursor;
 127         krb5_keytab_entry kt_entry;
 128
 129         ZERO_STRUCT(kt_entry);
 130         ZERO_STRUCT(cursor);
 131
 132         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 133         if (ret) {
 134                 return 0;
 135         }
 136
 137         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0)
 138         {
 139                 krb5_keyblock *keyp;
 140                 char *princ_s = NULL;
 141
 142                 if (kt_entry.vno != kvno && !ignore_kvno) {
 143                         goto cont;
 144                 }
 145
 146                 keyp = KRB5_KT_KEY(&kt_entry);
 147
 148                 if (KRB5_KEY_TYPE(keyp) != enctype) {
 149                         goto cont;
 150                 }
 151
 152                 ret = smb_krb5_unparse_name(talloc_tos(), context, kt_entry.principal,
 153                                             &princ_s);
 154                 if (ret) {
 155                         DEBUG(5, ("smb_krb5_unparse_name failed (%s)\n",
 156                                   error_message(ret)));
 157                         goto cont;
 158                 }
 159
 160                 if (strcmp(principal, princ_s) != 0) {
 161                         goto cont;
 162                 }
 163
 164                 /* match found - remove */
 165
 166                 DEBUG(10, ("found entry for principal %s, kvno %d, "
 167                            "enctype %d - trying to remove it\n",
 168                            princ_s, kt_entry.vno, KRB5_KEY_TYPE(keyp)));
 169
 170                 ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 171                 ZERO_STRUCT(cursor);
 172                 if (ret) {
 173                         DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
 174                                   error_message(ret)));
 175                         goto cont;
 176                 }
 177
 178                 ret = krb5_kt_remove_entry(context, keytab,
 179                                            &kt_entry);
 180                 if (ret) {
 181                         DEBUG(5, ("krb5_kt_remove_entry failed (%s)\n",
 182                                   error_message(ret)));
 183                         goto cont;
 184                 }
 185                 DEBUG(10, ("removed entry for principal %s, kvno %d, "
 186                            "enctype %d\n", princ_s, kt_entry.vno,
 187                            KRB5_KEY_TYPE(keyp)));
 188
 189                 ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 190                 if (ret) {
 191                         DEBUG(5, ("krb5_kt_start_seq_get failed (%s)\n",
 192                                   error_message(ret)));
 193                         goto cont;
 194                 }
 195
 196 cont:
 197                 smb_krb5_kt_free_entry(context, &kt_entry);
 198                 TALLOC_FREE(princ_s);
 199         }
 200
 201         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 202         if (ret) {
 203                 DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
 204                           error_message(ret)));
 205         }
 206
 207         return ret;
 208 }
 209
 210 static krb5_error_code libnet_keytab_add_entry(krb5_context context,
 211                                                krb5_keytab keytab,
 212                                                krb5_kvno kvno,
 213                                                const char *princ_s,
 214                                                krb5_enctype enctype,
 215                                                krb5_data password)
 216 {
 217         krb5_keyblock *keyp;
 218         krb5_keytab_entry kt_entry;
 219         krb5_error_code ret;
 220         krb5_principal salt_princ = NULL;
 221         char *salt_princ_s;
 222
 223         /* remove duplicates first ... */
 224         ret = libnet_keytab_remove_entries(context, keytab, princ_s, kvno,
 225                                            enctype, false);
 226         if (ret) {
 227                 DEBUG(1, ("libnet_keytab_remove_entries failed: %s\n",
 228                           error_message(ret)));
 229         }
 230
 231         ZERO_STRUCT(kt_entry);
 232
 233         kt_entry.vno = kvno;
 234
 235         ret = smb_krb5_parse_name(context, princ_s, &kt_entry.principal);
 236         if (ret) {
 237                 DEBUG(1, ("smb_krb5_parse_name(%s) failed (%s)\n",
 238                           princ_s, error_message(ret)));
 239                 return ret;
 240         }
 241
 242         keyp = KRB5_KT_KEY(&kt_entry);
 243
 244         salt_princ_s = kerberos_secrets_fetch_salt_princ();
 245         if (salt_princ_s == NULL) {
 246                 ret = KRB5KRB_ERR_GENERIC;
 247                 goto done;
 248         }
 249
 250         ret = krb5_parse_name(context, salt_princ_s, &salt_princ);
 251         SAFE_FREE(salt_princ_s);
 252         if (ret != 0) {
 253                 ret = KRB5KRB_ERR_GENERIC;
 254                 goto done;
 255         }
 256
 257         ret = create_kerberos_key_from_string(context,
 258                                               kt_entry.principal,
 259                                               salt_princ,
 260                                               &password,
 261                                               keyp,
 262                                               enctype,
 263                                               true);
 264         krb5_free_principal(context, salt_princ);
 265         if (ret != 0) {
 266                 ret = KRB5KRB_ERR_GENERIC;
 267                 goto done;
 268         }
 269
 270         ret = krb5_kt_add_entry(context, keytab, &kt_entry);
 271         if (ret) {
 272                 DEBUG(1, ("adding entry to keytab failed (%s)\n",
 273                           error_message(ret)));
 274         }
 275
 276 done:
 277         krb5_free_keyblock_contents(context, keyp);
 278         krb5_free_principal(context, kt_entry.principal);
 279         ZERO_STRUCT(kt_entry);
 280         smb_krb5_kt_free_entry(context, &kt_entry);
 281
 282         return ret;
 283 }
 284
 285 krb5_error_code libnet_keytab_add(struct libnet_keytab_context *ctx)
 286 {
 287         krb5_error_code ret = 0;
 288         uint32_t i;
 289
 290
 291         if (ctx->clean_old_entries) {
 292                 DEBUG(0, ("cleaning old entries...\n"));
 293                 for (i=0; i < ctx->count; i++) {
 294                         struct libnet_keytab_entry *entry = &ctx->entries[i];
 295
 296                         ret = libnet_keytab_remove_entries(ctx->context,
 297                                                            ctx->keytab,
 298                                                            entry->principal,
 299                                                            0,
 300                                                            entry->enctype,
 301                                                            true);
 302                         if (ret) {
 303                                 DEBUG(1,("libnet_keytab_add: Failed to remove "
 304                                          "old entries for %s (enctype %u): %s\n",
 305                                          entry->principal, entry->enctype,
 306                                          error_message(ret)));
 307                                 return ret;
 308                         }
 309                 }
 310         }
 311
 312         for (i=0; i<ctx->count; i++) {
 313
 314                 struct libnet_keytab_entry *entry = &ctx->entries[i];
 315                 krb5_data password;
 316
 317                 ZERO_STRUCT(password);
 318                 password.data = (char *)entry->password.data;
 319                 password.length = entry->password.length;
 320
 321                 ret = libnet_keytab_add_entry(ctx->context,
 322                                               ctx->keytab,
 323                                               entry->kvno,
 324                                               entry->principal,
 325                                               entry->enctype,
 326                                               password);
 327                 if (ret) {
 328                         DEBUG(1,("libnet_keytab_add: "
 329                                 "Failed to add entry to keytab file\n"));
 330                         return ret;
 331                 }
 332         }
 333
 334         return ret;
 335 }
 336
 337 struct libnet_keytab_entry *libnet_keytab_search(struct libnet_keytab_context *ctx,
 338                                                  const char *principal,
 339                                                  int kvno,
 340                                                  const krb5_enctype enctype,
 341                                                  TALLOC_CTX *mem_ctx)
 342 {
 343         krb5_error_code ret = 0;
 344         krb5_kt_cursor cursor;
 345         krb5_keytab_entry kt_entry;
 346         struct libnet_keytab_entry *entry = NULL;
 347
 348         ZERO_STRUCT(kt_entry);
 349         ZERO_STRUCT(cursor);
 350
 351         ret = krb5_kt_start_seq_get(ctx->context, ctx->keytab, &cursor);
 352         if (ret) {
 353                 DEBUG(10, ("krb5_kt_start_seq_get failed: %s\n",
 354                           error_message(ret)));
 355                 return NULL;
 356         }
 357
 358         while (krb5_kt_next_entry(ctx->context, ctx->keytab, &kt_entry, &cursor) == 0)
 359         {
 360                 krb5_keyblock *keyp;
 361                 char *princ_s = NULL;
 362
 363                 entry = NULL;
 364
 365                 if (kt_entry.vno != kvno) {
 366                         goto cont;
 367                 }
 368
 369                 keyp = KRB5_KT_KEY(&kt_entry);
 370
 371                 if (KRB5_KEY_TYPE(keyp) != enctype) {
 372                         goto cont;
 373                 }
 374
 375                 entry = talloc_zero(mem_ctx, struct libnet_keytab_entry);
 376                 if (!entry) {
 377                         DEBUG(3, ("talloc failed\n"));
 378                         goto fail;
 379                 }
 380
 381                 ret = smb_krb5_unparse_name(entry, ctx->context, kt_entry.principal,
 382                                             &princ_s);
 383                 if (ret) {
 384                         goto cont;
 385                 }
 386
 387                 if (strcmp(principal, princ_s) != 0) {
 388                         goto cont;
 389                 }
 390
 391                 entry->principal = talloc_strdup(entry, princ_s);
 392                 if (!entry->principal) {
 393                         DEBUG(3, ("talloc_strdup_failed\n"));
 394                         goto fail;
 395                 }
 396
 397                 entry->name = talloc_move(entry, &princ_s);
 398
 399                 entry->password = data_blob_talloc(entry, KRB5_KEY_DATA(keyp),
 400                                                    KRB5_KEY_LENGTH(keyp));
 401                 if (!entry->password.data) {
 402                         DEBUG(3, ("data_blob_talloc failed\n"));
 403                         goto fail;
 404                 }
 405
 406                 DEBUG(10, ("found entry\n"));
 407
 408                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 409                 break;
 410
 411 fail:
 412                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 413                 TALLOC_FREE(entry);
 414                 break;
 415
 416 cont:
 417                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 418                 TALLOC_FREE(entry);
 419                 continue;
 420         }
 421
 422         krb5_kt_end_seq_get(ctx->context, ctx->keytab, &cursor);
 423         return entry;
 424 }
 425
 426 /**
 427  * Helper function to add data to the list
 428  * of keytab entries. It builds the prefix from the input.
 429  */
 430 NTSTATUS libnet_keytab_add_to_keytab_entries(TALLOC_CTX *mem_ctx,
 431                                              struct libnet_keytab_context *ctx,
 432                                              uint32_t kvno,
 433                                              const char *name,
 434                                              const char *prefix,
 435                                              const krb5_enctype enctype,
 436                                              DATA_BLOB blob)
 437 {
 438         struct libnet_keytab_entry entry;
 439
 440         entry.kvno = kvno;
 441         entry.name = talloc_strdup(mem_ctx, name);
 442         entry.principal = talloc_asprintf(mem_ctx, "%s%s%s@%s",
 443                                           prefix ? prefix : "",
 444                                           prefix ? "/" : "",
 445                                           name, ctx->dns_domain_name);
 446         entry.enctype = enctype;
 447         entry.password = blob;
 448         NT_STATUS_HAVE_NO_MEMORY(entry.name);
 449         NT_STATUS_HAVE_NO_MEMORY(entry.principal);
 450         NT_STATUS_HAVE_NO_MEMORY(entry.password.data);
 451
 452         ADD_TO_ARRAY(mem_ctx, struct libnet_keytab_entry, entry,
 453                      &ctx->entries, &ctx->count);
 454         NT_STATUS_HAVE_NO_MEMORY(ctx->entries);
 455
 456         return NT_STATUS_OK;
 457 }
 458
 459 #endif /* HAVE_KRB5 */