source3/passdb/machine_sid.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Password and authentication handling
   4    Copyright (C) Jeremy Allison                 1996-2002
   5    Copyright (C) Andrew Tridgell                2002
   6    Copyright (C) Gerald (Jerry) Carter          2000
   7    Copyright (C) Stefan (metze) Metzmacher      2002
   8
   9    This program is free software; you can redistribute it and/or modify
  10    it under the terms of the GNU General Public License as published by
  11    the Free Software Foundation; either version 3 of the License, or
  12    (at your option) any later version.
  13
  14    This program is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17    GNU General Public License for more details.
  18
  19    You should have received a copy of the GNU General Public License
  20    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  21 */
  22
  23 #include "includes.h"
  24 #include "passdb/machine_sid.h"
  25 #include "secrets.h"
  26 #include "dbwrap/dbwrap.h"
  27 #include "../libcli/security/security.h"
  28
  29 /* NOTE! the global_sam_sid is the SID of our local SAM. This is only
  30    equal to the domain SID when we are a DC, otherwise its our
  31    workstation SID */
  32 static struct dom_sid *global_sam_sid=NULL;
  33
  34 #undef DBGC_CLASS
  35 #define DBGC_CLASS DBGC_PASSDB
  36
  37 /****************************************************************************
  38  Read a SID from a file. This is for compatibility with the old MACHINE.SID
  39  style of SID storage
  40 ****************************************************************************/
  41
  42 static bool read_sid_from_file(const char *fname, struct dom_sid *sid)
  43 {
  44         char *line = NULL;
  45         size_t n;
  46         ssize_t len;
  47         bool ret = false;
  48         FILE *f = NULL;
  49
  50         f = fopen(fname, "r");
  51         if (f == NULL) {
  52                 return false;
  53         }
  54
  55         len = getline(&line, &n, f);
  56         if (len >= 0) {
  57                 ret = string_to_sid(sid, line);
  58                 SAFE_FREE(line);
  59         }
  60
  61         fclose(f);
  62         return ret;
  63 }
  64
  65 /*
  66   generate a random sid - used to build our own sid if we don't have one
  67 */
  68 static void generate_random_sid(struct dom_sid *sid)
  69 {
  70         int i;
  71         uchar raw_sid_data[12];
  72
  73         *sid = (struct dom_sid) {
  74                 .sid_rev_num = 1,
  75                 .id_auth[5] = 5,
  76         };
  77
  78         sid->sub_auths[sid->num_auths++] = 21;
  79
  80         generate_random_buffer(raw_sid_data, 12);
  81         for (i = 0; i < 3; i++)
  82                 sid->sub_auths[sid->num_auths++] = IVAL(raw_sid_data, i*4);
  83 }
  84
  85 /****************************************************************************
  86  Generate the global machine sid.
  87 ****************************************************************************/
  88
  89 static struct dom_sid *pdb_generate_sam_sid(void)
  90 {
  91         struct dom_sid domain_sid;
  92         char *fname = NULL;
  93         struct dom_sid *sam_sid;
  94
  95         if(!(sam_sid=SMB_MALLOC_P(struct dom_sid)))
  96                 return NULL;
  97
  98         if ( IS_DC ) {
  99                 if (secrets_fetch_domain_sid(lp_workgroup(), &domain_sid)) {
 100                         sid_copy(sam_sid, &domain_sid);
 101                         return sam_sid;
 102                 }
 103         }
 104
 105         if (secrets_fetch_domain_sid(lp_netbios_name(), sam_sid)) {
 106
 107                 /* We got our sid. If not a pdc/bdc, we're done. */
 108                 if ( !IS_DC )
 109                         return sam_sid;
 110
 111                 if (!secrets_fetch_domain_sid(lp_workgroup(), &domain_sid)) {
 112
 113                         /* No domain sid and we're a pdc/bdc. Store it */
 114
 115                         if (!secrets_store_domain_sid(lp_workgroup(), sam_sid)) {
 116                                 DEBUG(0,("pdb_generate_sam_sid: Can't store domain SID as a pdc/bdc.\n"));
 117                                 SAFE_FREE(sam_sid);
 118                                 return NULL;
 119                         }
 120                         return sam_sid;
 121                 }
 122
 123                 if (!dom_sid_equal(&domain_sid, sam_sid)) {
 124
 125                         /* Domain name sid doesn't match global sam sid. Re-store domain sid as 'local' sid. */
 126
 127                         DEBUG(0,("pdb_generate_sam_sid: Mismatched SIDs as a pdc/bdc.\n"));
 128                         if (!secrets_store_domain_sid(lp_netbios_name(), &domain_sid)) {
 129                                 DEBUG(0,("pdb_generate_sam_sid: Can't re-store domain SID for local sid as PDC/BDC.\n"));
 130                                 SAFE_FREE(sam_sid);
 131                                 return NULL;
 132                         }
 133                         return sam_sid;
 134                 }
 135
 136                 return sam_sid;
 137         }
 138
 139         /* check for an old MACHINE.SID file for backwards compatibility */
 140         if (asprintf(&fname, "%s/MACHINE.SID", lp_private_dir()) == -1) {
 141                 SAFE_FREE(sam_sid);
 142                 return NULL;
 143         }
 144
 145         if (read_sid_from_file(fname, sam_sid)) {
 146                 /* remember it for future reference and unlink the old MACHINE.SID */
 147                 if (!secrets_store_domain_sid(lp_netbios_name(), sam_sid)) {
 148                         DEBUG(0,("pdb_generate_sam_sid: Failed to store SID from file.\n"));
 149                         SAFE_FREE(fname);
 150                         SAFE_FREE(sam_sid);
 151                         return NULL;
 152                 }
 153                 unlink(fname);
 154                 if ( !IS_DC ) {
 155                         if (!secrets_store_domain_sid(lp_workgroup(), sam_sid)) {
 156                                 DEBUG(0,("pdb_generate_sam_sid: Failed to store domain SID from file.\n"));
 157                                 SAFE_FREE(fname);
 158                                 SAFE_FREE(sam_sid);
 159                                 return NULL;
 160                         }
 161                 }
 162
 163                 /* Stored the old sid from MACHINE.SID successfully.*/
 164                 SAFE_FREE(fname);
 165                 return sam_sid;
 166         }
 167
 168         SAFE_FREE(fname);
 169
 170         /* we don't have the SID in secrets.tdb, we will need to
 171            generate one and save it */
 172         generate_random_sid(sam_sid);
 173
 174         if (!secrets_store_domain_sid(lp_netbios_name(), sam_sid)) {
 175                 DEBUG(0,("pdb_generate_sam_sid: Failed to store generated machine SID.\n"));
 176                 SAFE_FREE(sam_sid);
 177                 return NULL;
 178         }
 179         if ( IS_DC ) {
 180                 if (!secrets_store_domain_sid(lp_workgroup(), sam_sid)) {
 181                         DEBUG(0,("pdb_generate_sam_sid: Failed to store generated domain SID.\n"));
 182                         SAFE_FREE(sam_sid);
 183                         return NULL;
 184                 }
 185         }
 186
 187         return sam_sid;
 188 }
 189
 190 /* return our global_sam_sid */
 191 struct dom_sid *get_global_sam_sid(void)
 192 {
 193         struct db_context *db;
 194
 195         if (global_sam_sid != NULL)
 196                 return global_sam_sid;
 197
 198         /*
 199          * memory for global_sam_sid is allocated in
 200          * pdb_generate_sam_sid() as needed
 201          *
 202          * Note: this is guarded by a transaction
 203          *       to prevent races on startup which
 204          *       can happen with some dbwrap backends
 205          */
 206
 207         db = secrets_db_ctx();
 208         if (!db) {
 209                 smb_panic("could not open secrets db");
 210         }
 211
 212         if (dbwrap_transaction_start(db) != 0) {
 213                 smb_panic("could not start transaction on secrets db");
 214         }
 215
 216         if (!(global_sam_sid = pdb_generate_sam_sid())) {
 217                 dbwrap_transaction_cancel(db);
 218                 smb_panic("could not generate a machine SID");
 219         }
 220
 221         if (dbwrap_transaction_commit(db) != 0) {
 222                 smb_panic("could not start commit secrets db");
 223         }
 224
 225         return global_sam_sid;
 226 }
 227
 228 /**
 229  * Force get_global_sam_sid to requery the backends
 230  */
 231 void reset_global_sam_sid(void)
 232 {
 233         SAFE_FREE(global_sam_sid);
 234 }
 235
 236 /*****************************************************************
 237  Check if the SID is our sam SID (S-1-5-21-x-y-z).
 238 *****************************************************************/
 239
 240 bool sid_check_is_our_sam(const struct dom_sid *sid)
 241 {
 242         return dom_sid_equal(sid, get_global_sam_sid());
 243 }
 244
 245 /*****************************************************************
 246  Check if the SID is our domain SID (S-1-5-21-x-y-z).
 247 *****************************************************************/
 248
 249 bool sid_check_is_in_our_sam(const struct dom_sid *sid)
 250 {
 251         struct dom_sid dom_sid;
 252
 253         sid_copy(&dom_sid, sid);
 254         sid_split_rid(&dom_sid, NULL);
 255         return sid_check_is_our_sam(&dom_sid);
 256 }