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 "libnet/libnet_keytab.h"
  26
  27 #ifdef HAVE_KRB5
  28
  29 /****************************************************************
  30 ****************************************************************/
  31
  32 static int keytab_close(struct libnet_keytab_context *ctx)
  33 {
  34         if (!ctx) {
  35                 return 0;
  36         }
  37
  38         if (ctx->keytab && ctx->context) {
  39                 krb5_kt_close(ctx->context, ctx->keytab);
  40         }
  41
  42         if (ctx->context) {
  43                 krb5_free_context(ctx->context);
  44         }
  45
  46         if (ctx->ads) {
  47                 ads_destroy(&ctx->ads);
  48         }
  49
  50         TALLOC_FREE(ctx);
  51
  52         return 0;
  53 }
  54
  55 /****************************************************************
  56 ****************************************************************/
  57
  58 krb5_error_code libnet_keytab_init(TALLOC_CTX *mem_ctx,
  59                                    const char *keytab_name,
  60                                    struct libnet_keytab_context **ctx)
  61 {
  62         krb5_error_code ret = 0;
  63         krb5_context context = NULL;
  64         krb5_keytab keytab = NULL;
  65         const char *keytab_string = NULL;
  66
  67         struct libnet_keytab_context *r;
  68
  69         r = TALLOC_ZERO_P(mem_ctx, struct libnet_keytab_context);
  70         if (!r) {
  71                 return ENOMEM;
  72         }
  73
  74         talloc_set_destructor(r, keytab_close);
  75
  76         initialize_krb5_error_table();
  77         ret = krb5_init_context(&context);
  78         if (ret) {
  79                 DEBUG(1,("keytab_init: could not krb5_init_context: %s\n",
  80                         error_message(ret)));
  81                 return ret;
  82         }
  83
  84         ret = smb_krb5_open_keytab(context, keytab_name, true, &keytab);
  85         if (ret) {
  86                 DEBUG(1,("keytab_init: smb_krb5_open_keytab failed (%s)\n",
  87                         error_message(ret)));
  88                 krb5_free_context(context);
  89                 return ret;
  90         }
  91
  92         ret = smb_krb5_keytab_name(mem_ctx, context, keytab, &keytab_string);
  93         if (ret) {
  94                 krb5_kt_close(context, keytab);
  95                 krb5_free_context(context);
  96                 return ret;
  97         }
  98
  99         r->context = context;
 100         r->keytab = keytab;
 101         r->keytab_name = keytab_string;
 102         r->clean_old_entries = false;
 103
 104         *ctx = r;
 105
 106         return 0;
 107 }
 108
 109 /****************************************************************
 110 ****************************************************************/
 111
 112 /**
 113  * Remove all entries that have the given principal, kvno and enctype.
 114  */
 115 static krb5_error_code libnet_keytab_remove_entries(krb5_context context,
 116                                                     krb5_keytab keytab,
 117                                                     const char *principal,
 118                                                     int kvno,
 119                                                     const krb5_enctype enctype,
 120                                                     bool ignore_kvno)
 121 {
 122         krb5_error_code ret;
 123         krb5_kt_cursor cursor;
 124         krb5_keytab_entry kt_entry;
 125
 126         ZERO_STRUCT(kt_entry);
 127         ZERO_STRUCT(cursor);
 128
 129         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 130         if (ret) {
 131                 return 0;
 132         }
 133
 134         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0)
 135         {
 136                 krb5_keyblock *keyp;
 137                 char *princ_s = NULL;
 138
 139                 if (kt_entry.vno != kvno && !ignore_kvno) {
 140                         goto cont;
 141                 }
 142
 143                 keyp = KRB5_KT_KEY(&kt_entry);
 144
 145                 if (KRB5_KEY_TYPE(keyp) != enctype) {
 146                         goto cont;
 147                 }
 148
 149                 ret = smb_krb5_unparse_name(talloc_tos(), context, kt_entry.principal,
 150                                             &princ_s);
 151                 if (ret) {
 152                         DEBUG(5, ("smb_krb5_unparse_name failed (%s)\n",
 153                                   error_message(ret)));
 154                         goto cont;
 155                 }
 156
 157                 if (strcmp(principal, princ_s) != 0) {
 158                         goto cont;
 159                 }
 160
 161                 /* match found - remove */
 162
 163                 DEBUG(10, ("found entry for principal %s, kvno %d, "
 164                            "enctype %d - trying to remove it\n",
 165                            princ_s, kt_entry.vno, KRB5_KEY_TYPE(keyp)));
 166
 167                 ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 168                 ZERO_STRUCT(cursor);
 169                 if (ret) {
 170                         DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
 171                                   error_message(ret)));
 172                         goto cont;
 173                 }
 174
 175                 ret = krb5_kt_remove_entry(context, keytab,
 176                                            &kt_entry);
 177                 if (ret) {
 178                         DEBUG(5, ("krb5_kt_remove_entry failed (%s)\n",
 179                                   error_message(ret)));
 180                         goto cont;
 181                 }
 182                 DEBUG(10, ("removed entry for principal %s, kvno %d, "
 183                            "enctype %d\n", princ_s, kt_entry.vno,
 184                            KRB5_KEY_TYPE(keyp)));
 185
 186                 ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 187                 if (ret) {
 188                         DEBUG(5, ("krb5_kt_start_seq_get failed (%s)\n",
 189                                   error_message(ret)));
 190                         goto cont;
 191                 }
 192
 193 cont:
 194                 smb_krb5_kt_free_entry(context, &kt_entry);
 195                 TALLOC_FREE(princ_s);
 196         }
 197
 198         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 199         if (ret) {
 200                 DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
 201                           error_message(ret)));
 202         }
 203
 204         return ret;
 205 }
 206
 207 static krb5_error_code libnet_keytab_add_entry(krb5_context context,
 208                                                krb5_keytab keytab,
 209                                                krb5_kvno kvno,
 210                                                const char *princ_s,
 211                                                krb5_enctype enctype,
 212                                                krb5_data password)
 213 {
 214         krb5_keyblock *keyp;
 215         krb5_keytab_entry kt_entry;
 216         krb5_error_code ret;
 217
 218         /* remove duplicates first ... */
 219         ret = libnet_keytab_remove_entries(context, keytab, princ_s, kvno,
 220                                            enctype, false);
 221         if (ret) {
 222                 DEBUG(1, ("libnet_keytab_remove_entries failed: %s\n",
 223                           error_message(ret)));
 224         }
 225
 226         ZERO_STRUCT(kt_entry);
 227
 228         kt_entry.vno = kvno;
 229
 230         ret = smb_krb5_parse_name(context, princ_s, &kt_entry.principal);
 231         if (ret) {
 232                 DEBUG(1, ("smb_krb5_parse_name(%s) failed (%s)\n",
 233                           princ_s, error_message(ret)));
 234                 return ret;
 235         }
 236
 237         keyp = KRB5_KT_KEY(&kt_entry);
 238
 239         if (create_kerberos_key_from_string(context, kt_entry.principal,
 240                                             &password, keyp, enctype, true))
 241         {
 242                 ret = KRB5KRB_ERR_GENERIC;
 243                 goto done;
 244         }
 245
 246         ret = krb5_kt_add_entry(context, keytab, &kt_entry);
 247         if (ret) {
 248                 DEBUG(1, ("adding entry to keytab failed (%s)\n",
 249                           error_message(ret)));
 250         }
 251
 252 done:
 253         krb5_free_keyblock_contents(context, keyp);
 254         krb5_free_principal(context, kt_entry.principal);
 255         ZERO_STRUCT(kt_entry);
 256         smb_krb5_kt_free_entry(context, &kt_entry);
 257
 258         return ret;
 259 }
 260
 261 krb5_error_code libnet_keytab_add(struct libnet_keytab_context *ctx)
 262 {
 263         krb5_error_code ret = 0;
 264         uint32_t i;
 265
 266
 267         if (ctx->clean_old_entries) {
 268                 DEBUG(0, ("cleaning old entries...\n"));
 269                 for (i=0; i < ctx->count; i++) {
 270                         struct libnet_keytab_entry *entry = &ctx->entries[i];
 271
 272                         ret = libnet_keytab_remove_entries(ctx->context,
 273                                                            ctx->keytab,
 274                                                            entry->principal,
 275                                                            0,
 276                                                            entry->enctype,
 277                                                            true);
 278                         if (ret) {
 279                                 DEBUG(1,("libnet_keytab_add: Failed to remove "
 280                                          "old entries for %s (enctype %u): %s\n",
 281                                          entry->principal, entry->enctype,
 282                                          error_message(ret)));
 283                                 return ret;
 284                         }
 285                 }
 286         }
 287
 288         for (i=0; i<ctx->count; i++) {
 289
 290                 struct libnet_keytab_entry *entry = &ctx->entries[i];
 291                 krb5_data password;
 292
 293                 ZERO_STRUCT(password);
 294                 password.data = (char *)entry->password.data;
 295                 password.length = entry->password.length;
 296
 297                 ret = libnet_keytab_add_entry(ctx->context,
 298                                               ctx->keytab,
 299                                               entry->kvno,
 300                                               entry->principal,
 301                                               entry->enctype,
 302                                               password);
 303                 if (ret) {
 304                         DEBUG(1,("libnet_keytab_add: "
 305                                 "Failed to add entry to keytab file\n"));
 306                         return ret;
 307                 }
 308         }
 309
 310         return ret;
 311 }
 312
 313 struct libnet_keytab_entry *libnet_keytab_search(struct libnet_keytab_context *ctx,
 314                                                  const char *principal,
 315                                                  int kvno,
 316                                                  const krb5_enctype enctype,
 317                                                  TALLOC_CTX *mem_ctx)
 318 {
 319         krb5_error_code ret = 0;
 320         krb5_kt_cursor cursor;
 321         krb5_keytab_entry kt_entry;
 322         struct libnet_keytab_entry *entry = NULL;
 323
 324         ZERO_STRUCT(kt_entry);
 325         ZERO_STRUCT(cursor);
 326
 327         ret = krb5_kt_start_seq_get(ctx->context, ctx->keytab, &cursor);
 328         if (ret) {
 329                 DEBUG(10, ("krb5_kt_start_seq_get failed: %s\n",
 330                           error_message(ret)));
 331                 return NULL;
 332         }
 333
 334         while (krb5_kt_next_entry(ctx->context, ctx->keytab, &kt_entry, &cursor) == 0)
 335         {
 336                 krb5_keyblock *keyp;
 337                 char *princ_s = NULL;
 338
 339                 entry = NULL;
 340
 341                 if (kt_entry.vno != kvno) {
 342                         goto cont;
 343                 }
 344
 345                 keyp = KRB5_KT_KEY(&kt_entry);
 346
 347                 if (KRB5_KEY_TYPE(keyp) != enctype) {
 348                         goto cont;
 349                 }
 350
 351                 entry = talloc_zero(mem_ctx, struct libnet_keytab_entry);
 352                 if (!entry) {
 353                         DEBUG(3, ("talloc failed\n"));
 354                         goto fail;
 355                 }
 356
 357                 ret = smb_krb5_unparse_name(entry, ctx->context, kt_entry.principal,
 358                                             &princ_s);
 359                 if (ret) {
 360                         goto cont;
 361                 }
 362
 363                 if (strcmp(principal, princ_s) != 0) {
 364                         goto cont;
 365                 }
 366
 367                 entry->principal = talloc_strdup(entry, princ_s);
 368                 if (!entry->principal) {
 369                         DEBUG(3, ("talloc_strdup_failed\n"));
 370                         goto fail;
 371                 }
 372
 373                 entry->name = talloc_move(entry, &princ_s);
 374
 375                 entry->password = data_blob_talloc(entry, KRB5_KEY_DATA(keyp),
 376                                                    KRB5_KEY_LENGTH(keyp));
 377                 if (!entry->password.data) {
 378                         DEBUG(3, ("data_blob_talloc failed\n"));
 379                         goto fail;
 380                 }
 381
 382                 DEBUG(10, ("found entry\n"));
 383
 384                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 385                 break;
 386
 387 fail:
 388                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 389                 TALLOC_FREE(entry);
 390                 break;
 391
 392 cont:
 393                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 394                 TALLOC_FREE(entry);
 395                 continue;
 396         }
 397
 398         krb5_kt_end_seq_get(ctx->context, ctx->keytab, &cursor);
 399         return entry;
 400 }
 401
 402 /**
 403  * Helper function to add data to the list
 404  * of keytab entries. It builds the prefix from the input.
 405  */
 406 NTSTATUS libnet_keytab_add_to_keytab_entries(TALLOC_CTX *mem_ctx,
 407                                              struct libnet_keytab_context *ctx,
 408                                              uint32_t kvno,
 409                                              const char *name,
 410                                              const char *prefix,
 411                                              const krb5_enctype enctype,
 412                                              DATA_BLOB blob)
 413 {
 414         struct libnet_keytab_entry entry;
 415
 416         entry.kvno = kvno;
 417         entry.name = talloc_strdup(mem_ctx, name);
 418         entry.principal = talloc_asprintf(mem_ctx, "%s%s%s@%s",
 419                                           prefix ? prefix : "",
 420                                           prefix ? "/" : "",
 421                                           name, ctx->dns_domain_name);
 422         entry.enctype = enctype;
 423         entry.password = blob;
 424         NT_STATUS_HAVE_NO_MEMORY(entry.name);
 425         NT_STATUS_HAVE_NO_MEMORY(entry.principal);
 426         NT_STATUS_HAVE_NO_MEMORY(entry.password.data);
 427
 428         ADD_TO_ARRAY(mem_ctx, struct libnet_keytab_entry, entry,
 429                      &ctx->entries, &ctx->count);
 430         NT_STATUS_HAVE_NO_MEMORY(ctx->entries);
 431
 432         return NT_STATUS_OK;
 433 }
 434
 435 #endif /* HAVE_KRB5 */