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 **lines;
  45         int numlines;
  46         bool ret;
  47
  48         lines = file_lines_load(fname, &numlines,0, NULL);
  49
  50         if (!lines || numlines < 1) {
  51                 TALLOC_FREE(lines);
  52                 return False;
  53         }
  54
  55         ret = string_to_sid(sid, lines[0]);
  56         TALLOC_FREE(lines);
  57         return ret;
  58 }
  59
  60 /*
  61   generate a random sid - used to build our own sid if we don't have one
  62 */
  63 static void generate_random_sid(struct dom_sid *sid)
  64 {
  65         int i;
  66         uchar raw_sid_data[12];
  67
  68         ZERO_STRUCTP(sid);
  69
  70         sid->sid_rev_num = 1;
  71         sid->id_auth[5] = 5;
  72         sid->num_auths = 0;
  73         sid->sub_auths[sid->num_auths++] = 21;
  74
  75         generate_random_buffer(raw_sid_data, 12);
  76         for (i = 0; i < 3; i++)
  77                 sid->sub_auths[sid->num_auths++] = IVAL(raw_sid_data, i*4);
  78 }
  79
  80 /****************************************************************************
  81  Generate the global machine sid.
  82 ****************************************************************************/
  83
  84 static struct dom_sid *pdb_generate_sam_sid(void)
  85 {
  86         struct dom_sid domain_sid;
  87         char *fname = NULL;
  88         struct dom_sid *sam_sid;
  89
  90         if(!(sam_sid=SMB_MALLOC_P(struct dom_sid)))
  91                 return NULL;
  92
  93         if ( IS_DC ) {
  94                 if (secrets_fetch_domain_sid(lp_workgroup(), &domain_sid)) {
  95                         sid_copy(sam_sid, &domain_sid);
  96                         return sam_sid;
  97                 }
  98         }
  99
 100         if (secrets_fetch_domain_sid(lp_netbios_name(), sam_sid)) {
 101
 102                 /* We got our sid. If not a pdc/bdc, we're done. */
 103                 if ( !IS_DC )
 104                         return sam_sid;
 105
 106                 if (!secrets_fetch_domain_sid(lp_workgroup(), &domain_sid)) {
 107
 108                         /* No domain sid and we're a pdc/bdc. Store it */
 109
 110                         if (!secrets_store_domain_sid(lp_workgroup(), sam_sid)) {
 111                                 DEBUG(0,("pdb_generate_sam_sid: Can't store domain SID as a pdc/bdc.\n"));
 112                                 SAFE_FREE(sam_sid);
 113                                 return NULL;
 114                         }
 115                         return sam_sid;
 116                 }
 117
 118                 if (!dom_sid_equal(&domain_sid, sam_sid)) {
 119
 120                         /* Domain name sid doesn't match global sam sid. Re-store domain sid as 'local' sid. */
 121
 122                         DEBUG(0,("pdb_generate_sam_sid: Mismatched SIDs as a pdc/bdc.\n"));
 123                         if (!secrets_store_domain_sid(lp_netbios_name(), &domain_sid)) {
 124                                 DEBUG(0,("pdb_generate_sam_sid: Can't re-store domain SID for local sid as PDC/BDC.\n"));
 125                                 SAFE_FREE(sam_sid);
 126                                 return NULL;
 127                         }
 128                         return sam_sid;
 129                 }
 130
 131                 return sam_sid;
 132         }
 133
 134         /* check for an old MACHINE.SID file for backwards compatibility */
 135         if (asprintf(&fname, "%s/MACHINE.SID", lp_private_dir()) == -1) {
 136                 SAFE_FREE(sam_sid);
 137                 return NULL;
 138         }
 139
 140         if (read_sid_from_file(fname, sam_sid)) {
 141                 /* remember it for future reference and unlink the old MACHINE.SID */
 142                 if (!secrets_store_domain_sid(lp_netbios_name(), sam_sid)) {
 143                         DEBUG(0,("pdb_generate_sam_sid: Failed to store SID from file.\n"));
 144                         SAFE_FREE(fname);
 145                         SAFE_FREE(sam_sid);
 146                         return NULL;
 147                 }
 148                 unlink(fname);
 149                 if ( !IS_DC ) {
 150                         if (!secrets_store_domain_sid(lp_workgroup(), sam_sid)) {
 151                                 DEBUG(0,("pdb_generate_sam_sid: Failed to store domain SID from file.\n"));
 152                                 SAFE_FREE(fname);
 153                                 SAFE_FREE(sam_sid);
 154                                 return NULL;
 155                         }
 156                 }
 157
 158                 /* Stored the old sid from MACHINE.SID successfully.*/
 159                 SAFE_FREE(fname);
 160                 return sam_sid;
 161         }
 162
 163         SAFE_FREE(fname);
 164
 165         /* we don't have the SID in secrets.tdb, we will need to
 166            generate one and save it */
 167         generate_random_sid(sam_sid);
 168
 169         if (!secrets_store_domain_sid(lp_netbios_name(), sam_sid)) {
 170                 DEBUG(0,("pdb_generate_sam_sid: Failed to store generated machine SID.\n"));
 171                 SAFE_FREE(sam_sid);
 172                 return NULL;
 173         }
 174         if ( IS_DC ) {
 175                 if (!secrets_store_domain_sid(lp_workgroup(), sam_sid)) {
 176                         DEBUG(0,("pdb_generate_sam_sid: Failed to store generated domain SID.\n"));
 177                         SAFE_FREE(sam_sid);
 178                         return NULL;
 179                 }
 180         }
 181
 182         return sam_sid;
 183 }
 184
 185 /* return our global_sam_sid */
 186 struct dom_sid *get_global_sam_sid(void)
 187 {
 188         struct db_context *db;
 189
 190         if (global_sam_sid != NULL)
 191                 return global_sam_sid;
 192
 193         /*
 194          * memory for global_sam_sid is allocated in
 195          * pdb_generate_sam_sid() as needed
 196          *
 197          * Note: this is guarded by a transaction
 198          *       to prevent races on startup which
 199          *       can happen with some dbwrap backends
 200          */
 201
 202         db = secrets_db_ctx();
 203         if (!db) {
 204                 smb_panic("could not open secrets db");
 205         }
 206
 207         if (dbwrap_transaction_start(db) != 0) {
 208                 smb_panic("could not start transaction on secrets db");
 209         }
 210
 211         if (!(global_sam_sid = pdb_generate_sam_sid())) {
 212                 dbwrap_transaction_cancel(db);
 213                 smb_panic("could not generate a machine SID");
 214         }
 215
 216         if (dbwrap_transaction_commit(db) != 0) {
 217                 smb_panic("could not start commit secrets db");
 218         }
 219
 220         return global_sam_sid;
 221 }
 222
 223 /**
 224  * Force get_global_sam_sid to requery the backends
 225  */
 226 void reset_global_sam_sid(void)
 227 {
 228         SAFE_FREE(global_sam_sid);
 229 }
 230
 231 /*****************************************************************
 232  Check if the SID is our sam SID (S-1-5-21-x-y-z).
 233 *****************************************************************/
 234
 235 bool sid_check_is_our_sam(const struct dom_sid *sid)
 236 {
 237         return dom_sid_equal(sid, get_global_sam_sid());
 238 }
 239
 240 /*****************************************************************
 241  Check if the SID is our domain SID (S-1-5-21-x-y-z).
 242 *****************************************************************/
 243
 244 bool sid_check_is_in_our_sam(const struct dom_sid *sid)
 245 {
 246         struct dom_sid dom_sid;
 247
 248         sid_copy(&dom_sid, sid);
 249         sid_split_rid(&dom_sid, NULL);
 250         return sid_check_is_our_sam(&dom_sid);
 251 }