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 #define SHARE_DATABASE_VERSION_V3 3 /* canonicalized sharenames as lower case */
  30
  31 #define SHARE_SECURITY_DB_KEY_PREFIX_STR "SECDESC/"
  32 /* Map generic permissions to file object specific permissions */
  33
  34 extern const struct generic_mapping file_generic_mapping;
  35
  36 static int delete_fn(struct db_record *rec, void *priv)
  37 {
  38         rec->delete_rec(rec);
  39         return 0;
  40 }
  41
  42 /*****************************************************
  43  Looking for keys of the form: SHARE_SECURITY_DB_KEY_PREFIX_STR + "non lower case str".
  44  If we find one re-write it into a canonical case form.
  45 *****************************************************/
  46
  47 static int upgrade_v2_to_v3(struct db_record *rec, void *priv)
  48 {
  49         size_t prefix_len = strlen(SHARE_SECURITY_DB_KEY_PREFIX_STR);
  50         const char *servicename = NULL;
  51         char *c_servicename = NULL;
  52         char *newkey = NULL;
  53         bool *p_upgrade_ok = (bool *)priv;
  54         NTSTATUS status;
  55
  56         /* Is there space for a one character sharename ? */
  57         if (rec->key.dsize <= prefix_len+2) {
  58                 return 0;
  59         }
  60
  61         /* Does it start with the share key prefix ? */
  62         if (memcmp(rec->key.dptr, SHARE_SECURITY_DB_KEY_PREFIX_STR,
  63                         prefix_len) != 0) {
  64                 return 0;
  65         }
  66
  67         /* Is it a null terminated string as a key ? */
  68         if (rec->key.dptr[rec->key.dsize-1] != '\0') {
  69                 return 0;
  70         }
  71
  72         /* Bytes after the prefix are the sharename string. */
  73         servicename = (char *)&rec->key.dptr[prefix_len];
  74         c_servicename = canonicalize_servicename(talloc_tos(), servicename);
  75         if (!c_servicename) {
  76                 smb_panic("out of memory upgrading share security db from v2 -> v3");
  77         }
  78
  79         if (strcmp(servicename, c_servicename) == 0) {
  80                 /* Old and new names match. No canonicalization needed. */
  81                 TALLOC_FREE(c_servicename);
  82                 return 0;
  83         }
  84
  85         /* Oops. Need to canonicalize name, delete old then store new. */
  86         status = rec->delete_rec(rec);
  87         if (!NT_STATUS_IS_OK(status)) {
  88                 DEBUG(1, ("upgrade_v2_to_v3: Failed to delete secdesc for "
  89                           "%s: %s\n", rec->key.dptr, nt_errstr(status)));
  90                 TALLOC_FREE(c_servicename);
  91                 *p_upgrade_ok = false;
  92                 return -1;
  93         } else {
  94                 DEBUG(10, ("upgrade_v2_to_v3: deleted secdesc for "
  95                           "%s\n", rec->key.dptr ));
  96         }
  97
  98         if (!(newkey = talloc_asprintf(talloc_tos(),
  99                         SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 100                         c_servicename))) {
 101                 smb_panic("out of memory upgrading share security db from v2 -> v3");
 102         }
 103
 104         status = dbwrap_store(share_db,
 105                                 string_term_tdb_data(newkey),
 106                                 rec->value,
 107                                 TDB_REPLACE);
 108
 109         if (!NT_STATUS_IS_OK(status)) {
 110                 DEBUG(1, ("upgrade_v2_to_v3: Failed to store secdesc for "
 111                           "%s: %s\n", c_servicename, nt_errstr(status)));
 112                 TALLOC_FREE(c_servicename);
 113                 TALLOC_FREE(newkey);
 114                 *p_upgrade_ok = false;
 115                 return -1;
 116         } else {
 117                 DEBUG(10, ("upgrade_v2_to_v3: stored secdesc for "
 118                           "%s\n", newkey ));
 119         }
 120
 121         TALLOC_FREE(newkey);
 122         TALLOC_FREE(c_servicename);
 123
 124         return 0;
 125 }
 126
 127 bool share_info_db_init(void)
 128 {
 129         const char *vstring = "INFO/version";
 130         int32 vers_id;
 131         int ret;
 132         bool upgrade_ok = true;
 133
 134         if (share_db != NULL) {
 135                 return True;
 136         }
 137
 138         share_db = db_open(NULL, state_path("share_info.tdb"), 0,
 139                                  TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
 140         if (share_db == NULL) {
 141                 DEBUG(0,("Failed to open share info database %s (%s)\n",
 142                         state_path("share_info.tdb"), strerror(errno) ));
 143                 return False;
 144         }
 145
 146         vers_id = dbwrap_fetch_int32(share_db, vstring);
 147         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 148                 return true;
 149         }
 150
 151         if (share_db->transaction_start(share_db) != 0) {
 152                 DEBUG(0, ("transaction_start failed\n"));
 153                 TALLOC_FREE(share_db);
 154                 return false;
 155         }
 156
 157         vers_id = dbwrap_fetch_int32(share_db, vstring);
 158         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 159                 /*
 160                  * Race condition
 161                  */
 162                 if (share_db->transaction_cancel(share_db)) {
 163                         smb_panic("transaction_cancel failed");
 164                 }
 165                 return true;
 166         }
 167
 168         /* Move to at least V2. */
 169
 170         /* Cope with byte-reversed older versions of the db. */
 171         if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
 172                 /* Written on a bigendian machine with old fetch_int code. Save as le. */
 173
 174                 if (dbwrap_store_int32(share_db, vstring,
 175                                        SHARE_DATABASE_VERSION_V2) != 0) {
 176                         DEBUG(0, ("dbwrap_store_int32 failed\n"));
 177                         goto cancel;
 178                 }
 179                 vers_id = SHARE_DATABASE_VERSION_V2;
 180         }
 181
 182         if (vers_id != SHARE_DATABASE_VERSION_V2) {
 183                 ret = share_db->traverse(share_db, delete_fn, NULL);
 184                 if (ret < 0) {
 185                         DEBUG(0, ("traverse failed\n"));
 186                         goto cancel;
 187                 }
 188                 if (dbwrap_store_int32(share_db, vstring,
 189                                        SHARE_DATABASE_VERSION_V2) != 0) {
 190                         DEBUG(0, ("dbwrap_store_int32 failed\n"));
 191                         goto cancel;
 192                 }
 193         }
 194
 195         /* Finally upgrade to version 3, with canonicalized sharenames. */
 196
 197         ret = share_db->traverse(share_db, upgrade_v2_to_v3, &upgrade_ok);
 198         if (ret < 0 || upgrade_ok == false) {
 199                 DEBUG(0, ("traverse failed\n"));
 200                 goto cancel;
 201         }
 202         if (dbwrap_store_int32(share_db, vstring,
 203                                SHARE_DATABASE_VERSION_V3) != 0) {
 204                 DEBUG(0, ("dbwrap_store_int32 failed\n"));
 205                 goto cancel;
 206         }
 207
 208         if (share_db->transaction_commit(share_db) != 0) {
 209                 DEBUG(0, ("transaction_commit failed\n"));
 210                 return false;
 211         }
 212
 213         return true;
 214
 215  cancel:
 216         if (share_db->transaction_cancel(share_db)) {
 217                 smb_panic("transaction_cancel failed");
 218         }
 219
 220         return false;
 221 }
 222
 223 /*******************************************************************
 224  Fake up a Everyone, default access as a default.
 225  def_access is a GENERIC_XXX access mode.
 226  ********************************************************************/
 227
 228 SEC_DESC *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32 def_access)
 229 {
 230         uint32_t sa;
 231         SEC_ACE ace;
 232         SEC_ACL *psa = NULL;
 233         SEC_DESC *psd = NULL;
 234         uint32 spec_access = def_access;
 235
 236         se_map_generic(&spec_access, &file_generic_mapping);
 237
 238         sa = (def_access | spec_access );
 239         init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
 240
 241         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
 242                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 243                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 244                                     psa, psize);
 245         }
 246
 247         if (!psd) {
 248                 DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
 249                 return NULL;
 250         }
 251
 252         return psd;
 253 }
 254
 255 /*******************************************************************
 256  Pull a security descriptor from the share tdb.
 257  ********************************************************************/
 258
 259 SEC_DESC *get_share_security( TALLOC_CTX *ctx, const char *servicename,
 260                               size_t *psize)
 261 {
 262         char *key;
 263         SEC_DESC *psd = NULL;
 264         TDB_DATA data;
 265         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 266         NTSTATUS status;
 267
 268         if (!c_servicename) {
 269                 return NULL;
 270         }
 271
 272         if (!share_info_db_init()) {
 273                 TALLOC_FREE(c_servicename);
 274                 return NULL;
 275         }
 276
 277         if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {
 278                 TALLOC_FREE(c_servicename);
 279                 DEBUG(0, ("talloc_asprintf failed\n"));
 280                 return NULL;
 281         }
 282
 283         TALLOC_FREE(c_servicename);
 284
 285         data = dbwrap_fetch_bystring(share_db, talloc_tos(), key);
 286
 287         TALLOC_FREE(key);
 288
 289         if (data.dptr == NULL) {
 290                 return get_share_security_default(ctx, psize,
 291                                                   GENERIC_ALL_ACCESS);
 292         }
 293
 294         status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
 295
 296         TALLOC_FREE(data.dptr);
 297
 298         if (!NT_STATUS_IS_OK(status)) {
 299                 DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
 300                           nt_errstr(status)));
 301                 return get_share_security_default(ctx, psize,
 302                                                   GENERIC_ALL_ACCESS);
 303         }
 304
 305         if (psd) {
 306                 *psize = ndr_size_security_descriptor(psd, NULL, 0);
 307         } else {
 308                 return get_share_security_default(ctx, psize,
 309                                                   GENERIC_ALL_ACCESS);
 310         }
 311
 312         return psd;
 313 }
 314
 315 /*******************************************************************
 316  Store a security descriptor in the share db.
 317  ********************************************************************/
 318
 319 bool set_share_security(const char *share_name, SEC_DESC *psd)
 320 {
 321         TALLOC_CTX *frame = talloc_stackframe();
 322         char *key;
 323         bool ret = False;
 324         TDB_DATA blob;
 325         NTSTATUS status;
 326         char *c_share_name = canonicalize_servicename(frame, share_name);
 327
 328         if (!c_share_name) {
 329                 goto out;
 330         }
 331
 332         if (!share_info_db_init()) {
 333                 goto out;
 334         }
 335
 336         status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
 337
 338         if (!NT_STATUS_IS_OK(status)) {
 339                 DEBUG(0, ("marshall_sec_desc failed: %s\n",
 340                           nt_errstr(status)));
 341                 goto out;
 342         }
 343
 344         if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {
 345                 DEBUG(0, ("talloc_asprintf failed\n"));
 346                 goto out;
 347         }
 348
 349         status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
 350                                     TDB_REPLACE);
 351         if (!NT_STATUS_IS_OK(status)) {
 352                 DEBUG(1, ("set_share_security: Failed to store secdesc for "
 353                           "%s: %s\n", share_name, nt_errstr(status)));
 354                 goto out;
 355         }
 356
 357         DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
 358         ret = True;
 359
 360  out:
 361         TALLOC_FREE(frame);
 362         return ret;
 363 }
 364
 365 /*******************************************************************
 366  Delete a security descriptor.
 367 ********************************************************************/
 368
 369 bool delete_share_security(const char *servicename)
 370 {
 371         TDB_DATA kbuf;
 372         char *key;
 373         NTSTATUS status;
 374         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 375
 376         if (!c_servicename) {
 377                 return NULL;
 378         }
 379
 380         if (!share_info_db_init()) {
 381                 TALLOC_FREE(c_servicename);
 382                 return False;
 383         }
 384
 385         if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 386                                     c_servicename))) {
 387                 TALLOC_FREE(c_servicename);
 388                 return False;
 389         }
 390         kbuf = string_term_tdb_data(key);
 391
 392         status = dbwrap_trans_delete(share_db, kbuf);
 393         if (!NT_STATUS_IS_OK(status)) {
 394                 DEBUG(0, ("delete_share_security: Failed to delete entry for "
 395                           "share %s: %s\n", c_servicename, nt_errstr(status)));
 396                 TALLOC_FREE(c_servicename);
 397                 return False;
 398         }
 399
 400         TALLOC_FREE(c_servicename);
 401         return True;
 402 }
 403
 404 /*******************************************************************
 405  Can this user access with share with the required permissions ?
 406 ********************************************************************/
 407
 408 bool share_access_check(const NT_USER_TOKEN *token, const char *sharename,
 409                         uint32 desired_access)
 410 {
 411         uint32 granted;
 412         NTSTATUS status;
 413         SEC_DESC *psd = NULL;
 414         size_t sd_size;
 415
 416         psd = get_share_security(talloc_tos(), sharename, &sd_size);
 417
 418         if (!psd) {
 419                 return True;
 420         }
 421
 422         status = se_access_check(psd, token, desired_access, &granted);
 423
 424         TALLOC_FREE(psd);
 425
 426         return NT_STATUS_IS_OK(status);
 427 }
 428
 429 /***************************************************************************
 430  Parse the contents of an acl string from a usershare file.
 431 ***************************************************************************/
 432
 433 bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, SEC_DESC **ppsd)
 434 {
 435         size_t s_size = 0;
 436         const char *pacl = acl_str;
 437         int num_aces = 0;
 438         SEC_ACE *ace_list = NULL;
 439         SEC_ACL *psa = NULL;
 440         SEC_DESC *psd = NULL;
 441         size_t sd_size = 0;
 442         int i;
 443
 444         *ppsd = NULL;
 445
 446         /* If the acl string is blank return "Everyone:R" */
 447         if (!*acl_str) {
 448                 SEC_DESC *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
 449                 if (!default_psd) {
 450                         return False;
 451                 }
 452                 *ppsd = default_psd;
 453                 return True;
 454         }
 455
 456         num_aces = 1;
 457
 458         /* Add the number of ',' characters to get the number of aces. */
 459         num_aces += count_chars(pacl,',');
 460
 461         ace_list = TALLOC_ARRAY(ctx, SEC_ACE, num_aces);
 462         if (!ace_list) {
 463                 return False;
 464         }
 465
 466         for (i = 0; i < num_aces; i++) {
 467                 uint32_t sa;
 468                 uint32 g_access;
 469                 uint32 s_access;
 470                 DOM_SID sid;
 471                 char *sidstr;
 472                 enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
 473
 474                 if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
 475                         DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
 476                                 "for ':' in string '%s'\n", pacl));
 477                         return False;
 478                 }
 479
 480                 if (!string_to_sid(&sid, sidstr)) {
 481                         DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
 482                                 sidstr ));
 483                         return False;
 484                 }
 485
 486                 switch (*pacl) {
 487                         case 'F': /* Full Control, ie. R+W */
 488                         case 'f': /* Full Control, ie. R+W */
 489                                 s_access = g_access = GENERIC_ALL_ACCESS;
 490                                 break;
 491                         case 'R': /* Read only. */
 492                         case 'r': /* Read only. */
 493                                 s_access = g_access = GENERIC_READ_ACCESS;
 494                                 break;
 495                         case 'D': /* Deny all to this SID. */
 496                         case 'd': /* Deny all to this SID. */
 497                                 type = SEC_ACE_TYPE_ACCESS_DENIED;
 498                                 s_access = g_access = GENERIC_ALL_ACCESS;
 499                                 break;
 500                         default:
 501                                 DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
 502                                         pacl ));
 503                                 return False;
 504                 }
 505
 506                 pacl++;
 507                 if (*pacl && *pacl != ',') {
 508                         DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
 509                                 pacl ));
 510                         return False;
 511                 }
 512                 pacl++; /* Go past any ',' */
 513
 514                 se_map_generic(&s_access, &file_generic_mapping);
 515                 sa = (g_access | s_access);
 516                 init_sec_ace(&ace_list[i], &sid, type, sa, 0);
 517         }
 518
 519         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
 520                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 521                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 522                                     psa, &sd_size);
 523         }
 524
 525         if (!psd) {
 526                 DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
 527                 return False;
 528         }
 529
 530         *ppsd = psd;
 531         return True;
 532 }