source3/lib/sharesec.c

   1 /*
   2  *  Unix SMB/Netbios implementation.
   3  *  SEC_DESC handling functions
   4  *  Copyright (C) Jeremy R. Allison            1995-2003.
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 3 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include "includes.h"
  21
  22 /*******************************************************************
  23  Create the share security tdb.
  24  ********************************************************************/
  25
  26 static struct db_context *share_db; /* used for share security descriptors */
  27 #define SHARE_DATABASE_VERSION_V1 1
  28 #define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */
  29
  30 /* Map generic permissions to file object specific permissions */
  31
  32 extern const struct generic_mapping file_generic_mapping;
  33
  34 static int delete_fn(struct db_record *rec, void *priv)
  35 {
  36         rec->delete_rec(rec);
  37         return 0;
  38 }
  39
  40 static bool share_info_db_init(void)
  41 {
  42         const char *vstring = "INFO/version";
  43         int32 vers_id;
  44
  45         if (share_db != NULL) {
  46                 return True;
  47         }
  48
  49         share_db = db_open(NULL, state_path("share_info.tdb"), 0,
  50                                  TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
  51         if (share_db == NULL) {
  52                 DEBUG(0,("Failed to open share info database %s (%s)\n",
  53                         state_path("share_info.tdb"), strerror(errno) ));
  54                 return False;
  55         }
  56
  57         vers_id = dbwrap_fetch_int32(share_db, vstring);
  58         if (vers_id == SHARE_DATABASE_VERSION_V2) {
  59                 return true;
  60         }
  61
  62         if (share_db->transaction_start(share_db) != 0) {
  63                 DEBUG(0, ("transaction_start failed\n"));
  64                 TALLOC_FREE(share_db);
  65                 return false;
  66         }
  67
  68         vers_id = dbwrap_fetch_int32(share_db, vstring);
  69         if (vers_id == SHARE_DATABASE_VERSION_V2) {
  70                 /*
  71                  * Race condition
  72                  */
  73                 if (share_db->transaction_cancel(share_db)) {
  74                         smb_panic("transaction_cancel failed");
  75                 }
  76                 return true;
  77         }
  78
  79         /* Cope with byte-reversed older versions of the db. */
  80         if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
  81                 /* Written on a bigendian machine with old fetch_int code. Save as le. */
  82
  83                 if (dbwrap_store_int32(share_db, vstring,
  84                                        SHARE_DATABASE_VERSION_V2) != 0) {
  85                         DEBUG(0, ("dbwrap_store_int32 failed\n"));
  86                         goto cancel;
  87                 }
  88                 vers_id = SHARE_DATABASE_VERSION_V2;
  89         }
  90
  91         if (vers_id != SHARE_DATABASE_VERSION_V2) {
  92                 int ret;
  93                 ret = share_db->traverse(share_db, delete_fn, NULL);
  94                 if (ret < 0) {
  95                         DEBUG(0, ("traverse failed\n"));
  96                         goto cancel;
  97                 }
  98                 if (dbwrap_store_int32(share_db, vstring,
  99                                        SHARE_DATABASE_VERSION_V2) != 0) {
 100                         DEBUG(0, ("dbwrap_store_int32 failed\n"));
 101                         goto cancel;
 102                 }
 103         }
 104
 105         if (share_db->transaction_commit(share_db) != 0) {
 106                 DEBUG(0, ("transaction_commit failed\n"));
 107                 return false;
 108         }
 109
 110         return true;
 111
 112  cancel:
 113         if (share_db->transaction_cancel(share_db)) {
 114                 smb_panic("transaction_cancel failed");
 115         }
 116
 117         return false;
 118 }
 119
 120 /*******************************************************************
 121  Fake up a Everyone, default access as a default.
 122  def_access is a GENERIC_XXX access mode.
 123  ********************************************************************/
 124
 125 SEC_DESC *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32 def_access)
 126 {
 127         uint32_t sa;
 128         SEC_ACE ace;
 129         SEC_ACL *psa = NULL;
 130         SEC_DESC *psd = NULL;
 131         uint32 spec_access = def_access;
 132
 133         se_map_generic(&spec_access, &file_generic_mapping);
 134
 135         sa = (def_access | spec_access );
 136         init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
 137
 138         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
 139                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 140                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 141                                     psa, psize);
 142         }
 143
 144         if (!psd) {
 145                 DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
 146                 return NULL;
 147         }
 148
 149         return psd;
 150 }
 151
 152 /*******************************************************************
 153  Pull a security descriptor from the share tdb.
 154  ********************************************************************/
 155
 156 SEC_DESC *get_share_security( TALLOC_CTX *ctx, const char *servicename,
 157                               size_t *psize)
 158 {
 159         char *key;
 160         SEC_DESC *psd = NULL;
 161         TDB_DATA data;
 162         NTSTATUS status;
 163
 164         if (!share_info_db_init()) {
 165                 return NULL;
 166         }
 167
 168         if (!(key = talloc_asprintf(ctx, "SECDESC/%s", servicename))) {
 169                 DEBUG(0, ("talloc_asprintf failed\n"));
 170                 return NULL;
 171         }
 172
 173         data = dbwrap_fetch_bystring(share_db, talloc_tos(), key);
 174
 175         TALLOC_FREE(key);
 176
 177         if (data.dptr == NULL) {
 178                 return get_share_security_default(ctx, psize,
 179                                                   GENERIC_ALL_ACCESS);
 180         }
 181
 182         status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
 183
 184         TALLOC_FREE(data.dptr);
 185
 186         if (!NT_STATUS_IS_OK(status)) {
 187                 DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
 188                           nt_errstr(status)));
 189                 return NULL;
 190         }
 191
 192         if (psd)
 193                 *psize = ndr_size_security_descriptor(psd, NULL, 0);
 194
 195         return psd;
 196 }
 197
 198 /*******************************************************************
 199  Store a security descriptor in the share db.
 200  ********************************************************************/
 201
 202 bool set_share_security(const char *share_name, SEC_DESC *psd)
 203 {
 204         TALLOC_CTX *frame;
 205         char *key;
 206         bool ret = False;
 207         TDB_DATA blob;
 208         NTSTATUS status;
 209
 210         if (!share_info_db_init()) {
 211                 return False;
 212         }
 213
 214         frame = talloc_stackframe();
 215
 216         status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
 217
 218         if (!NT_STATUS_IS_OK(status)) {
 219                 DEBUG(0, ("marshall_sec_desc failed: %s\n",
 220                           nt_errstr(status)));
 221                 goto out;
 222         }
 223
 224         if (!(key = talloc_asprintf(frame, "SECDESC/%s", share_name))) {
 225                 DEBUG(0, ("talloc_asprintf failed\n"));
 226                 goto out;
 227         }
 228
 229         status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
 230                                     TDB_REPLACE);
 231         if (!NT_STATUS_IS_OK(status)) {
 232                 DEBUG(1, ("set_share_security: Failed to store secdesc for "
 233                           "%s: %s\n", share_name, nt_errstr(status)));
 234                 goto out;
 235         }
 236
 237         DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
 238         ret = True;
 239
 240  out:
 241         TALLOC_FREE(frame);
 242         return ret;
 243 }
 244
 245 /*******************************************************************
 246  Delete a security descriptor.
 247 ********************************************************************/
 248
 249 bool delete_share_security(const char *servicename)
 250 {
 251         TDB_DATA kbuf;
 252         char *key;
 253         NTSTATUS status;
 254
 255         if (!share_info_db_init()) {
 256                 return False;
 257         }
 258
 259         if (!(key = talloc_asprintf(talloc_tos(), "SECDESC/%s",
 260                                     servicename))) {
 261                 return False;
 262         }
 263         kbuf = string_term_tdb_data(key);
 264
 265         status = dbwrap_trans_delete(share_db, kbuf);
 266         if (!NT_STATUS_IS_OK(status)) {
 267                 DEBUG(0, ("delete_share_security: Failed to delete entry for "
 268                           "share %s: %s\n", servicename, nt_errstr(status)));
 269                 return False;
 270         }
 271
 272         return True;
 273 }
 274
 275 /*******************************************************************
 276  Can this user access with share with the required permissions ?
 277 ********************************************************************/
 278
 279 bool share_access_check(const NT_USER_TOKEN *token, const char *sharename,
 280                         uint32 desired_access)
 281 {
 282         uint32 granted;
 283         NTSTATUS status;
 284         SEC_DESC *psd = NULL;
 285         size_t sd_size;
 286
 287         psd = get_share_security(talloc_tos(), sharename, &sd_size);
 288
 289         if (!psd) {
 290                 return True;
 291         }
 292
 293         status = se_access_check(psd, token, desired_access, &granted);
 294
 295         TALLOC_FREE(psd);
 296
 297         return NT_STATUS_IS_OK(status);
 298 }
 299
 300 /***************************************************************************
 301  Parse the contents of an acl string from a usershare file.
 302 ***************************************************************************/
 303
 304 bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, SEC_DESC **ppsd)
 305 {
 306         size_t s_size = 0;
 307         const char *pacl = acl_str;
 308         int num_aces = 0;
 309         SEC_ACE *ace_list = NULL;
 310         SEC_ACL *psa = NULL;
 311         SEC_DESC *psd = NULL;
 312         size_t sd_size = 0;
 313         int i;
 314
 315         *ppsd = NULL;
 316
 317         /* If the acl string is blank return "Everyone:R" */
 318         if (!*acl_str) {
 319                 SEC_DESC *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
 320                 if (!default_psd) {
 321                         return False;
 322                 }
 323                 *ppsd = default_psd;
 324                 return True;
 325         }
 326
 327         num_aces = 1;
 328
 329         /* Add the number of ',' characters to get the number of aces. */
 330         num_aces += count_chars(pacl,',');
 331
 332         ace_list = TALLOC_ARRAY(ctx, SEC_ACE, num_aces);
 333         if (!ace_list) {
 334                 return False;
 335         }
 336
 337         for (i = 0; i < num_aces; i++) {
 338                 uint32_t sa;
 339                 uint32 g_access;
 340                 uint32 s_access;
 341                 DOM_SID sid;
 342                 char *sidstr;
 343                 enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
 344
 345                 if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
 346                         DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
 347                                 "for ':' in string '%s'\n", pacl));
 348                         return False;
 349                 }
 350
 351                 if (!string_to_sid(&sid, sidstr)) {
 352                         DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
 353                                 sidstr ));
 354                         return False;
 355                 }
 356
 357                 switch (*pacl) {
 358                         case 'F': /* Full Control, ie. R+W */
 359                         case 'f': /* Full Control, ie. R+W */
 360                                 s_access = g_access = GENERIC_ALL_ACCESS;
 361                                 break;
 362                         case 'R': /* Read only. */
 363                         case 'r': /* Read only. */
 364                                 s_access = g_access = GENERIC_READ_ACCESS;
 365                                 break;
 366                         case 'D': /* Deny all to this SID. */
 367                         case 'd': /* Deny all to this SID. */
 368                                 type = SEC_ACE_TYPE_ACCESS_DENIED;
 369                                 s_access = g_access = GENERIC_ALL_ACCESS;
 370                                 break;
 371                         default:
 372                                 DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
 373                                         pacl ));
 374                                 return False;
 375                 }
 376
 377                 pacl++;
 378                 if (*pacl && *pacl != ',') {
 379                         DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
 380                                 pacl ));
 381                         return False;
 382                 }
 383                 pacl++; /* Go past any ',' */
 384
 385                 se_map_generic(&s_access, &file_generic_mapping);
 386                 sa = (g_access | s_access);
 387                 init_sec_ace(&ace_list[i], &sid, type, sa, 0);
 388         }
 389
 390         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
 391                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 392                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 393                                     psa, &sd_size);
 394         }
 395
 396         if (!psd) {
 397                 DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
 398                 return False;
 399         }
 400
 401         *ppsd = psd;
 402         return True;
 403 }