source3/libsmb/samlogon_cache.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Net_sam_logon info3 helpers
   4    Copyright (C) Alexander Bokovoy              2002.
   5    Copyright (C) Andrew Bartlett                2002.
   6    Copyright (C) Gerald Carter                  2003.
   7    Copyright (C) Tim Potter                     2003.
   8    Copyright (C) Guenther Deschner              2008.
   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 "replace.h"
  25 #include "samlogon_cache.h"
  26 #include "system/filesys.h"
  27 #include "system/time.h"
  28 #include "lib/util/debug.h"
  29 #include "lib/util/talloc_stack.h"
  30 #include "lib/util/memory.h" /* for SAFE_FREE() */
  31 #include "source3/lib/util_path.h"
  32 #include "librpc/gen_ndr/ndr_krb5pac.h"
  33 #include "../libcli/security/security.h"
  34 #include "util_tdb.h"
  35
  36 #define NETSAMLOGON_TDB "netsamlogon_cache.tdb"
  37
  38 static TDB_CONTEXT *netsamlogon_tdb = NULL;
  39
  40 /***********************************************************************
  41  open the tdb
  42  ***********************************************************************/
  43
  44 bool netsamlogon_cache_init(void)
  45 {
  46         bool first_try = true;
  47         char *path = NULL;
  48         int ret;
  49         struct tdb_context *tdb;
  50
  51         if (netsamlogon_tdb) {
  52                 return true;
  53         }
  54
  55         path = cache_path(talloc_tos(), NETSAMLOGON_TDB);
  56         if (path == NULL) {
  57                 return false;
  58         }
  59 again:
  60         tdb = tdb_open_log(path, 0, TDB_DEFAULT|TDB_INCOMPATIBLE_HASH,
  61                            O_RDWR | O_CREAT, 0600);
  62         if (tdb == NULL) {
  63                 DEBUG(0,("tdb_open_log('%s') - failed\n", path));
  64                 goto clear;
  65         }
  66
  67         ret = tdb_check(tdb, NULL, NULL);
  68         if (ret != 0) {
  69                 tdb_close(tdb);
  70                 DEBUG(0,("tdb_check('%s') - failed\n", path));
  71                 goto clear;
  72         }
  73
  74         netsamlogon_tdb = tdb;
  75         talloc_free(path);
  76         return true;
  77
  78 clear:
  79         if (!first_try) {
  80                 talloc_free(path);
  81                 return false;
  82         }
  83         first_try = false;
  84
  85         DEBUG(0,("retry after truncate for '%s'\n", path));
  86         ret = truncate(path, 0);
  87         if (ret == -1) {
  88                 DBG_ERR("truncate failed: %s\n", strerror(errno));
  89                 talloc_free(path);
  90                 return false;
  91         }
  92
  93         goto again;
  94 }
  95
  96 /***********************************************************************
  97  Clear cache getpwnam and getgroups entries from the winbindd cache
  98 ***********************************************************************/
  99
 100 void netsamlogon_clear_cached_user(const struct dom_sid *user_sid)
 101 {
 102         struct dom_sid_buf keystr;
 103
 104         if (!netsamlogon_cache_init()) {
 105                 DEBUG(0,("netsamlogon_clear_cached_user: cannot open "
 106                         "%s for write!\n",
 107                         NETSAMLOGON_TDB));
 108                 return;
 109         }
 110
 111         /* Prepare key as DOMAIN-SID/USER-RID string */
 112         dom_sid_str_buf(user_sid, &keystr);
 113
 114         DBG_DEBUG("SID [%s]\n", keystr.buf);
 115
 116         tdb_delete_bystring(netsamlogon_tdb, keystr.buf);
 117 }
 118
 119 /***********************************************************************
 120  Store a netr_SamInfo3 structure in a tdb for later user
 121  username should be in UTF-8 format
 122 ***********************************************************************/
 123
 124 bool netsamlogon_cache_store(const char *username, struct netr_SamInfo3 *info3)
 125 {
 126         uint8_t dummy = 0;
 127         TDB_DATA data = { .dptr = &dummy, .dsize = sizeof(dummy) };
 128         struct dom_sid_buf keystr;
 129         bool result = false;
 130         struct dom_sid  user_sid;
 131         TALLOC_CTX *tmp_ctx = talloc_stackframe();
 132         DATA_BLOB blob;
 133         enum ndr_err_code ndr_err;
 134         struct netsamlogoncache_entry r;
 135         int ret;
 136
 137         if (!info3) {
 138                 goto fail;
 139         }
 140
 141         if (!netsamlogon_cache_init()) {
 142                 D_WARNING("netsamlogon_cache_store: cannot open %s for write!\n",
 143                         NETSAMLOGON_TDB);
 144                 goto fail;
 145         }
 146
 147         /*
 148          * First write a record with just the domain sid for
 149          * netsamlogon_cache_domain_known. Use TDB_INSERT to avoid
 150          * overwriting potentially other data. We're just interested
 151          * in the existence of that record.
 152          */
 153         dom_sid_str_buf(info3->base.domain_sid, &keystr);
 154
 155         ret = tdb_store_bystring(netsamlogon_tdb, keystr.buf, data, TDB_INSERT);
 156
 157         if ((ret == -1) && (tdb_error(netsamlogon_tdb) != TDB_ERR_EXISTS)) {
 158                 D_WARNING("Could not store domain marker for %s: %s\n",
 159                             keystr.buf, tdb_errorstr(netsamlogon_tdb));
 160                 goto fail;
 161         }
 162
 163         sid_compose(&user_sid, info3->base.domain_sid, info3->base.rid);
 164
 165         /* Prepare key as DOMAIN-SID/USER-RID string */
 166         dom_sid_str_buf(&user_sid, &keystr);
 167
 168         DBG_DEBUG("SID [%s]\n", keystr.buf);
 169
 170         /* Prepare data */
 171
 172         if (info3->base.full_name.string == NULL) {
 173                 struct netr_SamInfo3 *cached_info3;
 174                 const char *full_name = NULL;
 175
 176                 cached_info3 = netsamlogon_cache_get(tmp_ctx, &user_sid);
 177                 if (cached_info3 != NULL) {
 178                         full_name = cached_info3->base.full_name.string;
 179                 }
 180
 181                 if (full_name != NULL) {
 182                         info3->base.full_name.string = talloc_strdup(info3, full_name);
 183                         if (info3->base.full_name.string == NULL) {
 184                                 goto fail;
 185                         }
 186                 }
 187         }
 188
 189         /* only Samba fills in the username, not sure why NT doesn't */
 190         /* so we fill it in since winbindd_getpwnam() makes use of it */
 191
 192         if (!info3->base.account_name.string) {
 193                 info3->base.account_name.string = talloc_strdup(info3, username);
 194                 if (info3->base.account_name.string == NULL) {
 195                         goto fail;
 196                 }
 197         }
 198
 199         r.timestamp = time(NULL);
 200         r.info3 = *info3;
 201
 202         /* avoid storing secret information */
 203         ZERO_STRUCT(r.info3.base.key);
 204         ZERO_STRUCT(r.info3.base.LMSessKey);
 205
 206         if (DEBUGLEVEL >= 10) {
 207                 NDR_PRINT_DEBUG(netsamlogoncache_entry, &r);
 208         }
 209
 210         ndr_err = ndr_push_struct_blob(&blob, tmp_ctx, &r,
 211                                        (ndr_push_flags_fn_t)ndr_push_netsamlogoncache_entry);
 212         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 213                 DBG_WARNING("failed to push entry to cache: %s\n",
 214                             ndr_errstr(ndr_err));
 215                 goto fail;
 216         }
 217
 218         data.dsize = blob.length;
 219         data.dptr = blob.data;
 220
 221         if (tdb_store_bystring(netsamlogon_tdb, keystr.buf, data, TDB_REPLACE) == 0) {
 222                 result = true;
 223         }
 224
 225 fail:
 226         TALLOC_FREE(tmp_ctx);
 227         return result;
 228 }
 229
 230 /***********************************************************************
 231  Retrieves a netr_SamInfo3 structure from a tdb.  Caller must
 232  free the user_info struct (talloced memory)
 233 ***********************************************************************/
 234
 235 struct netr_SamInfo3 *netsamlogon_cache_get(TALLOC_CTX *mem_ctx, const struct dom_sid *user_sid)
 236 {
 237         struct netr_SamInfo3 *info3 = NULL;
 238         TDB_DATA data;
 239         struct dom_sid_buf keystr;
 240         enum ndr_err_code ndr_err;
 241         DATA_BLOB blob;
 242         struct netsamlogoncache_entry r;
 243
 244         if (!netsamlogon_cache_init()) {
 245                 DEBUG(0,("netsamlogon_cache_get: cannot open %s for write!\n",
 246                         NETSAMLOGON_TDB));
 247                 return NULL;
 248         }
 249
 250         /* Prepare key as DOMAIN-SID/USER-RID string */
 251         dom_sid_str_buf(user_sid, &keystr);
 252         DBG_DEBUG("SID [%s]\n", keystr.buf);
 253         data = tdb_fetch_bystring( netsamlogon_tdb, keystr.buf );
 254
 255         if (!data.dptr) {
 256                 D_DEBUG("tdb fetch for %s is empty\n", keystr.buf);
 257                 return NULL;
 258         }
 259
 260         info3 = talloc_zero(mem_ctx, struct netr_SamInfo3);
 261         if (!info3) {
 262                 goto done;
 263         }
 264
 265         blob = data_blob_const(data.dptr, data.dsize);
 266
 267         ndr_err = ndr_pull_struct_blob_all(
 268                 &blob, mem_ctx, &r,
 269                 (ndr_pull_flags_fn_t)ndr_pull_netsamlogoncache_entry);
 270
 271         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 272                 D_WARNING("netsamlogon_cache_get: failed to pull entry from cache\n");
 273                 tdb_delete_bystring(netsamlogon_tdb, keystr.buf);
 274                 TALLOC_FREE(info3);
 275                 goto done;
 276         }
 277
 278         NDR_PRINT_DEBUG_LEVEL(DBGLVL_DEBUG, netsamlogoncache_entry, &r);
 279
 280         info3 = (struct netr_SamInfo3 *)talloc_memdup(mem_ctx, &r.info3,
 281                                                       sizeof(r.info3));
 282
 283  done:
 284         SAFE_FREE(data.dptr);
 285
 286         return info3;
 287 }
 288
 289 bool netsamlogon_cache_have(const struct dom_sid *sid)
 290 {
 291         struct dom_sid_buf keystr;
 292         bool ok;
 293
 294         if (!netsamlogon_cache_init()) {
 295                 DBG_WARNING("Cannot open %s\n", NETSAMLOGON_TDB);
 296                 return false;
 297         }
 298
 299         dom_sid_str_buf(sid, &keystr);
 300
 301         ok = tdb_exists(netsamlogon_tdb, string_term_tdb_data(keystr.buf));
 302         return ok;
 303 }
 304
 305 struct netsamlog_cache_forall_state {
 306         TALLOC_CTX *mem_ctx;
 307         int (*cb)(const char *sid_str,
 308                   time_t when_cached,
 309                   struct netr_SamInfo3 *,
 310                   void *private_data);
 311         void *private_data;
 312 };
 313
 314 static int netsamlog_cache_traverse_cb(struct tdb_context *tdb,
 315                                        TDB_DATA key,
 316                                        TDB_DATA data,
 317                                        void *private_data)
 318 {
 319         struct netsamlog_cache_forall_state *state =
 320                 (struct netsamlog_cache_forall_state *)private_data;
 321         TALLOC_CTX *mem_ctx = NULL;
 322         DATA_BLOB blob;
 323         const char *sid_str = NULL;
 324         struct dom_sid sid;
 325         struct netsamlogoncache_entry r;
 326         enum ndr_err_code ndr_err;
 327         int ret;
 328         bool ok;
 329
 330         if (key.dsize == 0) {
 331                 return 0;
 332         }
 333         if (key.dptr[key.dsize - 1] != '\0') {
 334                 return 0;
 335         }
 336         if (data.dptr == NULL) {
 337                 return 0;
 338         }
 339         sid_str = (char *)key.dptr;
 340
 341         ok = string_to_sid(&sid, sid_str);
 342         if (!ok) {
 343                 DBG_ERR("String to SID failed for %s\n", sid_str);
 344                 return -1;
 345         }
 346
 347         if (sid.num_auths != 5) {
 348                 return 0;
 349         }
 350
 351         mem_ctx = talloc_new(state->mem_ctx);
 352         if (mem_ctx == NULL) {
 353                 return -1;
 354         }
 355
 356         blob = data_blob_const(data.dptr, data.dsize);
 357
 358         ndr_err = ndr_pull_struct_blob(
 359                 &blob, state->mem_ctx, &r,
 360                 (ndr_pull_flags_fn_t)ndr_pull_netsamlogoncache_entry);
 361
 362         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 363                 DBG_ERR("failed to pull entry from cache\n");
 364                 return -1;
 365         }
 366
 367         ret = state->cb(sid_str, r.timestamp, &r.info3, state->private_data);
 368
 369         TALLOC_FREE(mem_ctx);
 370         return ret;
 371 }
 372
 373 int netsamlog_cache_for_all(int (*cb)(const char *sid_str,
 374                                       time_t when_cached,
 375                                       struct netr_SamInfo3 *,
 376                                       void *private_data),
 377                             void *private_data)
 378 {
 379         int ret;
 380         TALLOC_CTX *mem_ctx = NULL;
 381         struct netsamlog_cache_forall_state state;
 382
 383         if (!netsamlogon_cache_init()) {
 384                 DBG_ERR("Cannot open %s\n", NETSAMLOGON_TDB);
 385                 return -1;
 386         }
 387
 388         mem_ctx = talloc_init("netsamlog_cache_for_all");
 389         if (mem_ctx == NULL) {
 390                 return -1;
 391         }
 392
 393         state = (struct netsamlog_cache_forall_state) {
 394                 .mem_ctx = mem_ctx,
 395                 .cb = cb,
 396                 .private_data = private_data,
 397         };
 398
 399         ret = tdb_traverse_read(netsamlogon_tdb,
 400                                 netsamlog_cache_traverse_cb,
 401                                 &state);
 402
 403         TALLOC_FREE(state.mem_ctx);
 404         return ret;
 405 }