source/param/secrets.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Copyright (C) Andrew Tridgell 1992-2001
   4    Copyright (C) Andrew Bartlett      2002
   5    Copyright (C) Rafal Szczesniak     2002
   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 2 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, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 /* the Samba secrets database stores any generated, private information
  23    such as the local SID and machine trust password */
  24
  25 #include "includes.h"
  26 #include "secrets.h"
  27 #include "param/param.h"
  28 #include "system/filesys.h"
  29 #include "db_wrap.h"
  30 #include "lib/ldb/include/ldb.h"
  31 #include "lib/tdb/include/tdb.h"
  32 #include "lib/util/util_tdb.h"
  33 #include "dsdb/samdb/samdb.h"
  34
  35 static struct tdb_wrap *tdb;
  36
  37 /**
  38  * Use a TDB to store an incrementing random seed.
  39  *
  40  * Initialised to the current pid, the very first time Samba starts,
  41  * and incremented by one each time it is needed.
  42  *
  43  * @note Not called by systems with a working /dev/urandom.
  44  */
  45 static void get_rand_seed(int *new_seed)
  46 {
  47         *new_seed = getpid();
  48         if (tdb) {
  49                 tdb_change_int32_atomic(tdb->tdb, "INFO/random_seed", new_seed, 1);
  50         }
  51 }
  52
  53 /* close the secrets database */
  54 void secrets_shutdown(void)
  55 {
  56        talloc_free(tdb);
  57 }
  58
  59 /* open up the secrets database */
  60 BOOL secrets_init(void)
  61 {
  62         char *fname;
  63         uint8_t dummy;
  64
  65         if (tdb)
  66                 return True;
  67
  68         asprintf(&fname, "%s/secrets.tdb", lp_private_dir());
  69
  70         tdb = tdb_wrap_open(talloc_autofree_context(), fname, 0, TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
  71
  72         if (!tdb) {
  73                 DEBUG(0,("Failed to open %s\n", fname));
  74                 SAFE_FREE(fname);
  75                 return False;
  76         }
  77         SAFE_FREE(fname);
  78
  79         /**
  80          * Set a reseed function for the crypto random generator
  81          *
  82          * This avoids a problem where systems without /dev/urandom
  83          * could send the same challenge to multiple clients
  84          */
  85         set_rand_reseed_callback(get_rand_seed);
  86
  87         /* Ensure that the reseed is done now, while we are root, etc */
  88         generate_random_buffer(&dummy, sizeof(dummy));
  89
  90         return True;
  91 }
  92
  93 /*
  94   connect to the schannel ldb
  95 */
  96 struct ldb_context *secrets_db_connect(TALLOC_CTX *mem_ctx)
  97 {
  98         char *path;
  99         const char *url;
 100         struct ldb_context *ldb;
 101         BOOL existed;
 102         const char *init_ldif =
 103                 "dn: @ATTRIBUTES\n" \
 104                 "computerName: CASE_INSENSITIVE\n" \
 105                 "flatname: CASE_INSENSITIVE\n";
 106
 107         url = lp_secrets_url();
 108         if (!url || !url[0]) {
 109                 return NULL;
 110         }
 111
 112         path = private_path(mem_ctx, url);
 113         if (!path) {
 114                 return NULL;
 115         }
 116
 117         existed = file_exist(path);
 118
 119         /* Secrets.ldb *must* always be local.  If we call for a
 120          * system_session() we will recurse */
 121         ldb = ldb_wrap_connect(mem_ctx, path, NULL, NULL, 0, NULL);
 122         talloc_free(path);
 123         if (!ldb) {
 124                 return NULL;
 125         }
 126
 127         if (!existed) {
 128                 gendb_add_ldif(ldb, init_ldif);
 129         }
 130
 131         return ldb;
 132 }
 133
 134 struct dom_sid *secrets_get_domain_sid(TALLOC_CTX *mem_ctx,
 135                                        const char *domain)
 136 {
 137         struct ldb_context *ldb;
 138         struct ldb_message **msgs;
 139         int ldb_ret;
 140         const char *attrs[] = { "objectSid", NULL };
 141         struct dom_sid *result = NULL;
 142
 143         ldb = secrets_db_connect(mem_ctx);
 144         if (ldb == NULL) {
 145                 DEBUG(5, ("secrets_db_connect failed\n"));
 146                 return NULL;
 147         }
 148
 149         ldb_ret = gendb_search(ldb, ldb,
 150                                ldb_dn_new(mem_ctx, ldb, SECRETS_PRIMARY_DOMAIN_DN),
 151                                &msgs, attrs,
 152                                SECRETS_PRIMARY_DOMAIN_FILTER, domain);
 153
 154         if (ldb_ret == -1) {
 155                 DEBUG(5, ("Error searching for domain SID for %s: %s",
 156                           domain, ldb_errstring(ldb)));
 157                 talloc_free(ldb);
 158                 return NULL;
 159         }
 160
 161         if (ldb_ret == 0) {
 162                 DEBUG(5, ("Did not find domain record for %s\n", domain));
 163                 talloc_free(ldb);
 164                 return NULL;
 165         }
 166
 167         if (ldb_ret > 1) {
 168                 DEBUG(5, ("Found more than one (%d) domain records for %s\n",
 169                           ldb_ret, domain));
 170                 talloc_free(ldb);
 171                 return NULL;
 172         }
 173
 174         result = samdb_result_dom_sid(mem_ctx, msgs[0], "objectSid");
 175         if (result == NULL) {
 176                 DEBUG(0, ("Domain object for %s does not contain a SID!\n",
 177                           domain));
 178                 talloc_free(ldb);
 179                 return NULL;
 180         }
 181
 182         return result;
 183 }