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
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "libnet/libnet.h"
  23
  24 #ifdef HAVE_KRB5
  25
  26 /****************************************************************
  27 ****************************************************************/
  28
  29 static int keytab_close(struct libnet_keytab_context *ctx)
  30 {
  31         if (!ctx) {
  32                 return 0;
  33         }
  34
  35         if (ctx->keytab && ctx->context) {
  36                 krb5_kt_close(ctx->context, ctx->keytab);
  37         }
  38
  39         if (ctx->context) {
  40                 krb5_free_context(ctx->context);
  41         }
  42
  43         if (ctx->ads) {
  44                 ads_destroy(&ctx->ads);
  45         }
  46
  47         TALLOC_FREE(ctx);
  48
  49         return 0;
  50 }
  51
  52 /****************************************************************
  53 ****************************************************************/
  54
  55 krb5_error_code libnet_keytab_init(TALLOC_CTX *mem_ctx,
  56                                    const char *keytab_name,
  57                                    struct libnet_keytab_context **ctx)
  58 {
  59         krb5_error_code ret = 0;
  60         krb5_context context = NULL;
  61         krb5_keytab keytab = NULL;
  62         const char *keytab_string = NULL;
  63
  64         struct libnet_keytab_context *r;
  65
  66         r = TALLOC_ZERO_P(mem_ctx, struct libnet_keytab_context);
  67         if (!r) {
  68                 return ENOMEM;
  69         }
  70
  71         talloc_set_destructor(r, keytab_close);
  72
  73         initialize_krb5_error_table();
  74         ret = krb5_init_context(&context);
  75         if (ret) {
  76                 DEBUG(1,("keytab_init: could not krb5_init_context: %s\n",
  77                         error_message(ret)));
  78                 return ret;
  79         }
  80
  81         ret = smb_krb5_open_keytab(context, keytab_name, true, &keytab);
  82         if (ret) {
  83                 DEBUG(1,("keytab_init: smb_krb5_open_keytab failed (%s)\n",
  84                         error_message(ret)));
  85                 krb5_free_context(context);
  86                 return ret;
  87         }
  88
  89         ret = smb_krb5_keytab_name(mem_ctx, context, keytab, &keytab_string);
  90         if (ret) {
  91                 krb5_kt_close(context, keytab);
  92                 krb5_free_context(context);
  93                 return ret;
  94         }
  95
  96         r->context = context;
  97         r->keytab = keytab;
  98         r->keytab_name = keytab_string;
  99         r->clean_old_entries = false;
 100
 101         *ctx = r;
 102
 103         return 0;
 104 }
 105
 106 /****************************************************************
 107 ****************************************************************/
 108
 109 /**
 110  * Remove all entries that have the given principal, kvno and enctype.
 111  */
 112 static krb5_error_code libnet_keytab_remove_entries(krb5_context context,
 113                                                     krb5_keytab keytab,
 114                                                     const char *principal,
 115                                                     int kvno,
 116                                                     const krb5_enctype enctype,
 117                                                     bool ignore_kvno)
 118 {
 119         krb5_error_code ret;
 120         krb5_kt_cursor cursor;
 121         krb5_keytab_entry kt_entry;
 122
 123         ZERO_STRUCT(kt_entry);
 124         ZERO_STRUCT(cursor);
 125
 126         ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 127         if (ret) {
 128                 return 0;
 129         }
 130
 131         while (krb5_kt_next_entry(context, keytab, &kt_entry, &cursor) == 0)
 132         {
 133                 char *princ_s = NULL;
 134
 135                 if (kt_entry.vno != kvno && !ignore_kvno) {
 136                         goto cont;
 137                 }
 138
 139                 if (kt_entry.key.enctype != enctype) {
 140                         goto cont;
 141                 }
 142
 143                 ret = smb_krb5_unparse_name(context, kt_entry.principal,
 144                                             &princ_s);
 145                 if (ret) {
 146                         DEBUG(5, ("smb_krb5_unparse_name failed (%s)\n",
 147                                   error_message(ret)));
 148                         goto cont;
 149                 }
 150
 151                 if (strcmp(principal, princ_s) != 0) {
 152                         goto cont;
 153                 }
 154
 155                 /* match found - remove */
 156
 157                 DEBUG(10, ("found entry for principal %s, kvno %d, "
 158                            "enctype %d - trying to remove it\n",
 159                            princ_s, kt_entry.vno, kt_entry.key.enctype));
 160
 161                 ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 162                 ZERO_STRUCT(cursor);
 163                 if (ret) {
 164                         DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
 165                                   error_message(ret)));
 166                         goto cont;
 167                 }
 168
 169                 ret = krb5_kt_remove_entry(context, keytab,
 170                                            &kt_entry);
 171                 if (ret) {
 172                         DEBUG(5, ("krb5_kt_remove_entry failed (%s)\n",
 173                                   error_message(ret)));
 174                         goto cont;
 175                 }
 176                 DEBUG(10, ("removed entry for principal %s, kvno %d, "
 177                            "enctype %d\n", princ_s, kt_entry.vno,
 178                            kt_entry.key.enctype));
 179
 180                 ret = krb5_kt_start_seq_get(context, keytab, &cursor);
 181                 if (ret) {
 182                         DEBUG(5, ("krb5_kt_start_seq_get failed (%s)\n",
 183                                   error_message(ret)));
 184                         goto cont;
 185                 }
 186
 187 cont:
 188                 smb_krb5_kt_free_entry(context, &kt_entry);
 189                 SAFE_FREE(princ_s);
 190         }
 191
 192         ret = krb5_kt_end_seq_get(context, keytab, &cursor);
 193         if (ret) {
 194                 DEBUG(5, ("krb5_kt_end_seq_get failed (%s)\n",
 195                           error_message(ret)));
 196         }
 197
 198         return ret;
 199 }
 200
 201 static krb5_error_code libnet_keytab_add_entry(krb5_context context,
 202                                                krb5_keytab keytab,
 203                                                krb5_kvno kvno,
 204                                                const char *princ_s,
 205                                                krb5_enctype enctype,
 206                                                krb5_data password)
 207 {
 208         krb5_keyblock *keyp;
 209         krb5_keytab_entry kt_entry;
 210         krb5_error_code ret;
 211
 212         /* remove duplicates first ... */
 213         ret = libnet_keytab_remove_entries(context, keytab, princ_s, kvno,
 214                                            enctype, false);
 215         if (ret) {
 216                 DEBUG(1, ("libnet_keytab_remove_entries failed: %s\n",
 217                           error_message(ret)));
 218         }
 219
 220         ZERO_STRUCT(kt_entry);
 221
 222         kt_entry.vno = kvno;
 223
 224         ret = smb_krb5_parse_name(context, princ_s, &kt_entry.principal);
 225         if (ret) {
 226                 DEBUG(1, ("smb_krb5_parse_name(%s) failed (%s)\n",
 227                           princ_s, error_message(ret)));
 228                 return ret;
 229         }
 230
 231 #if !defined(HAVE_KRB5_KEYTAB_ENTRY_KEY) && !defined(HAVE_KRB5_KEYTAB_ENTRY_KEYBLOCK)
 232 #error krb5_keytab_entry has no key or keyblock member
 233 #endif
 234 #ifdef HAVE_KRB5_KEYTAB_ENTRY_KEY               /* MIT */
 235         keyp = &kt_entry.key;
 236 #endif
 237 #ifdef HAVE_KRB5_KEYTAB_ENTRY_KEYBLOCK          /* Heimdal */
 238         keyp = &kt_entry.keyblock;
 239 #endif
 240
 241         if (create_kerberos_key_from_string(context, kt_entry.principal,
 242                                             &password, keyp, enctype, true))
 243         {
 244                 ret = KRB5KRB_ERR_GENERIC;
 245                 goto done;
 246         }
 247
 248         ret = krb5_kt_add_entry(context, keytab, &kt_entry);
 249         if (ret) {
 250                 DEBUG(1, ("adding entry to keytab failed (%s)\n",
 251                           error_message(ret)));
 252         }
 253
 254 done:
 255         krb5_free_keyblock_contents(context, keyp);
 256         krb5_free_principal(context, kt_entry.principal);
 257         ZERO_STRUCT(kt_entry);
 258         smb_krb5_kt_free_entry(context, &kt_entry);
 259
 260         return ret;
 261 }
 262
 263 krb5_error_code libnet_keytab_add(struct libnet_keytab_context *ctx)
 264 {
 265         krb5_error_code ret = 0;
 266         uint32_t i;
 267
 268
 269         if (ctx->clean_old_entries) {
 270                 DEBUG(0, ("cleaning old entries...\n"));
 271                 for (i=0; i < ctx->count; i++) {
 272                         struct libnet_keytab_entry *entry = &ctx->entries[i];
 273
 274                         ret = libnet_keytab_remove_entries(ctx->context,
 275                                                            ctx->keytab,
 276                                                            entry->principal,
 277                                                            0,
 278                                                            entry->enctype,
 279                                                            true);
 280                         if (ret) {
 281                                 DEBUG(1,("libnet_keytab_add: Failed to remove "
 282                                          "old entries for %s (enctype %u): %s\n",
 283                                          entry->principal, entry->enctype,
 284                                          error_message(ret)));
 285                                 return ret;
 286                         }
 287                 }
 288         }
 289
 290         for (i=0; i<ctx->count; i++) {
 291
 292                 struct libnet_keytab_entry *entry = &ctx->entries[i];
 293                 krb5_data password;
 294
 295                 password.data = (char *)entry->password.data;
 296                 password.length = entry->password.length;
 297
 298                 ret = libnet_keytab_add_entry(ctx->context,
 299                                               ctx->keytab,
 300                                               entry->kvno,
 301                                               entry->principal,
 302                                               entry->enctype,
 303                                               password);
 304                 if (ret) {
 305                         DEBUG(1,("libnet_keytab_add: "
 306                                 "Failed to add entry to keytab file\n"));
 307                         return ret;
 308                 }
 309         }
 310
 311         return ret;
 312 }
 313
 314 struct libnet_keytab_entry *libnet_keytab_search(struct libnet_keytab_context *ctx,
 315                                                  const char *principal,
 316                                                  int kvno,
 317                                                  const krb5_enctype enctype,
 318                                                  TALLOC_CTX *mem_ctx)
 319 {
 320         krb5_error_code ret = 0;
 321         krb5_kt_cursor cursor;
 322         krb5_keytab_entry kt_entry;
 323         struct libnet_keytab_entry *entry = NULL;
 324
 325         ZERO_STRUCT(kt_entry);
 326         ZERO_STRUCT(cursor);
 327
 328         ret = krb5_kt_start_seq_get(ctx->context, ctx->keytab, &cursor);
 329         if (ret) {
 330                 DEBUG(10, ("krb5_kt_start_seq_get failed: %s",
 331                           error_message(ret)));
 332                 return NULL;
 333         }
 334
 335         while (krb5_kt_next_entry(ctx->context, ctx->keytab, &kt_entry, &cursor) == 0)
 336         {
 337                 char *princ_s = NULL;
 338
 339                 if (kt_entry.vno != kvno) {
 340                         goto cont;
 341                 }
 342
 343                 if (kt_entry.key.enctype != enctype) {
 344                         goto cont;
 345                 }
 346
 347                 ret = smb_krb5_unparse_name(ctx->context, kt_entry.principal,
 348                                             &princ_s);
 349                 if (ret) {
 350                         goto cont;
 351                 }
 352
 353                 if (strcmp(principal, princ_s) != 0) {
 354                         goto cont;
 355                 }
 356
 357                 entry = talloc_zero(mem_ctx, struct libnet_keytab_entry);
 358                 if (!entry) {
 359                         DEBUG(3, ("talloc failed\n"));
 360                         goto fail;
 361                 }
 362
 363                 entry->name = talloc_strdup(entry, princ_s);
 364                 if (!entry->name) {
 365                         DEBUG(3, ("talloc_strdup_failed\n"));
 366                         goto fail;
 367                 }
 368
 369                 entry->principal = talloc_strdup(entry, princ_s);
 370                 if (!entry->principal) {
 371                         DEBUG(3, ("talloc_strdup_failed\n"));
 372                         goto fail;
 373                 }
 374
 375                 entry->password = data_blob_talloc(entry, kt_entry.key.contents,
 376                                                    kt_entry.key.length);
 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                 SAFE_FREE(princ_s);
 386                 break;
 387
 388 fail:
 389                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 390                 SAFE_FREE(princ_s);
 391                 TALLOC_FREE(entry);
 392                 break;
 393
 394 cont:
 395                 smb_krb5_kt_free_entry(ctx->context, &kt_entry);
 396                 SAFE_FREE(princ_s);
 397                 continue;
 398         }
 399
 400         krb5_kt_end_seq_get(ctx->context, ctx->keytab, &cursor);
 401         return entry;
 402 }
 403
 404 #endif /* HAVE_KRB5 */