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 #include "system/filesys.h"
  22 #include "../libcli/security/security.h"
  23 #include "../librpc/gen_ndr/ndr_security.h"
  24 #include "dbwrap/dbwrap.h"
  25 #include "dbwrap/dbwrap_open.h"
  26 #include "util_tdb.h"
  27
  28 /*******************************************************************
  29  Create the share security tdb.
  30  ********************************************************************/
  31
  32 static struct db_context *share_db; /* used for share security descriptors */
  33 #define SHARE_DATABASE_VERSION_V1 1
  34 #define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */
  35 #define SHARE_DATABASE_VERSION_V3 3 /* canonicalized sharenames as lower case */
  36
  37 #define SHARE_SECURITY_DB_KEY_PREFIX_STR "SECDESC/"
  38 /* Map generic permissions to file object specific permissions */
  39
  40 extern const struct generic_mapping file_generic_mapping;
  41
  42 static int delete_fn(struct db_record *rec, void *priv)
  43 {
  44         dbwrap_record_delete(rec);
  45         return 0;
  46 }
  47
  48 /*****************************************************
  49  Looking for keys of the form: SHARE_SECURITY_DB_KEY_PREFIX_STR + "non lower case str".
  50  If we find one re-write it into a canonical case form.
  51 *****************************************************/
  52
  53 static int upgrade_v2_to_v3(struct db_record *rec, void *priv)
  54 {
  55         size_t prefix_len = strlen(SHARE_SECURITY_DB_KEY_PREFIX_STR);
  56         const char *servicename = NULL;
  57         char *c_servicename = NULL;
  58         char *newkey = NULL;
  59         bool *p_upgrade_ok = (bool *)priv;
  60         NTSTATUS status;
  61         TDB_DATA key;
  62         TDB_DATA value;
  63
  64         key = dbwrap_record_get_key(rec);
  65
  66         /* Is there space for a one character sharename ? */
  67         if (key.dsize <= prefix_len+2) {
  68                 return 0;
  69         }
  70
  71         /* Does it start with the share key prefix ? */
  72         if (memcmp(key.dptr, SHARE_SECURITY_DB_KEY_PREFIX_STR,
  73                         prefix_len) != 0) {
  74                 return 0;
  75         }
  76
  77         /* Is it a null terminated string as a key ? */
  78         if (key.dptr[key.dsize-1] != '\0') {
  79                 return 0;
  80         }
  81
  82         /* Bytes after the prefix are the sharename string. */
  83         servicename = (char *)&key.dptr[prefix_len];
  84         c_servicename = canonicalize_servicename(talloc_tos(), servicename);
  85         if (!c_servicename) {
  86                 smb_panic("out of memory upgrading share security db from v2 -> v3");
  87         }
  88
  89         if (strcmp(servicename, c_servicename) == 0) {
  90                 /* Old and new names match. No canonicalization needed. */
  91                 TALLOC_FREE(c_servicename);
  92                 return 0;
  93         }
  94
  95         /* Oops. Need to canonicalize name, delete old then store new. */
  96         status = dbwrap_record_delete(rec);
  97         if (!NT_STATUS_IS_OK(status)) {
  98                 DEBUG(1, ("upgrade_v2_to_v3: Failed to delete secdesc for "
  99                           "%s: %s\n", (const char *)key.dptr,
 100                           nt_errstr(status)));
 101                 TALLOC_FREE(c_servicename);
 102                 *p_upgrade_ok = false;
 103                 return -1;
 104         } else {
 105                 DEBUG(10, ("upgrade_v2_to_v3: deleted secdesc for "
 106                           "%s\n", (const char *)key.dptr));
 107         }
 108
 109         if (!(newkey = talloc_asprintf(talloc_tos(),
 110                         SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 111                         c_servicename))) {
 112                 smb_panic("out of memory upgrading share security db from v2 -> v3");
 113         }
 114
 115         value = dbwrap_record_get_value(rec);
 116         status = dbwrap_store(share_db,
 117                                 string_term_tdb_data(newkey),
 118                                 value,
 119                                 TDB_REPLACE);
 120
 121         if (!NT_STATUS_IS_OK(status)) {
 122                 DEBUG(1, ("upgrade_v2_to_v3: Failed to store secdesc for "
 123                           "%s: %s\n", c_servicename, nt_errstr(status)));
 124                 TALLOC_FREE(c_servicename);
 125                 TALLOC_FREE(newkey);
 126                 *p_upgrade_ok = false;
 127                 return -1;
 128         } else {
 129                 DEBUG(10, ("upgrade_v2_to_v3: stored secdesc for "
 130                           "%s\n", newkey ));
 131         }
 132
 133         TALLOC_FREE(newkey);
 134         TALLOC_FREE(c_servicename);
 135
 136         return 0;
 137 }
 138
 139 bool share_info_db_init(void)
 140 {
 141         const char *vstring = "INFO/version";
 142         int32 vers_id = 0;
 143         bool upgrade_ok = true;
 144         NTSTATUS status;
 145         char *db_path;
 146
 147         if (share_db != NULL) {
 148                 return True;
 149         }
 150
 151         db_path = state_path("share_info.tdb");
 152         if (db_path == NULL) {
 153                 return false;
 154         }
 155
 156         share_db = db_open(NULL, db_path, 0,
 157                            TDB_DEFAULT, O_RDWR|O_CREAT, 0600,
 158                            DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);
 159         if (share_db == NULL) {
 160                 DEBUG(0,("Failed to open share info database %s (%s)\n",
 161                          db_path, strerror(errno)));
 162                 TALLOC_FREE(db_path);
 163                 return False;
 164         }
 165         TALLOC_FREE(db_path);
 166
 167         status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);
 168         if (!NT_STATUS_IS_OK(status)) {
 169                 vers_id = 0;
 170         }
 171
 172         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 173                 return true;
 174         }
 175
 176         if (dbwrap_transaction_start(share_db) != 0) {
 177                 DEBUG(0, ("transaction_start failed\n"));
 178                 TALLOC_FREE(share_db);
 179                 return false;
 180         }
 181
 182         status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);
 183         if (!NT_STATUS_IS_OK(status)) {
 184                 vers_id = 0;
 185         }
 186
 187         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 188                 /*
 189                  * Race condition
 190                  */
 191                 if (dbwrap_transaction_cancel(share_db)) {
 192                         smb_panic("transaction_cancel failed");
 193                 }
 194                 return true;
 195         }
 196
 197         /* Move to at least V2. */
 198
 199         /* Cope with byte-reversed older versions of the db. */
 200         if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
 201                 /* Written on a bigendian machine with old fetch_int code. Save as le. */
 202
 203                 status = dbwrap_store_int32_bystring(
 204                         share_db, vstring, SHARE_DATABASE_VERSION_V2);
 205                 if (!NT_STATUS_IS_OK(status)) {
 206                         DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 207                                   nt_errstr(status)));
 208                         goto cancel;
 209                 }
 210                 vers_id = SHARE_DATABASE_VERSION_V2;
 211         }
 212
 213         if (vers_id != SHARE_DATABASE_VERSION_V2) {
 214                 status = dbwrap_traverse(share_db, delete_fn, NULL, NULL);
 215                 if (!NT_STATUS_IS_OK(status)) {
 216                         DEBUG(0, ("traverse failed\n"));
 217                         goto cancel;
 218                 }
 219                 status = dbwrap_store_int32_bystring(
 220                         share_db, vstring, SHARE_DATABASE_VERSION_V2);
 221                 if (!NT_STATUS_IS_OK(status)) {
 222                         DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 223                                   nt_errstr(status)));
 224                         goto cancel;
 225                 }
 226         }
 227
 228         /* Finally upgrade to version 3, with canonicalized sharenames. */
 229
 230         status = dbwrap_traverse(share_db, upgrade_v2_to_v3, &upgrade_ok, NULL);
 231         if (!NT_STATUS_IS_OK(status) || upgrade_ok == false) {
 232                 DEBUG(0, ("traverse failed\n"));
 233                 goto cancel;
 234         }
 235         status = dbwrap_store_int32_bystring(
 236                 share_db, vstring, SHARE_DATABASE_VERSION_V3);
 237         if (!NT_STATUS_IS_OK(status)) {
 238                 DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 239                           nt_errstr(status)));
 240                 goto cancel;
 241         }
 242
 243         if (dbwrap_transaction_commit(share_db) != 0) {
 244                 DEBUG(0, ("transaction_commit failed\n"));
 245                 return false;
 246         }
 247
 248         return true;
 249
 250  cancel:
 251         if (dbwrap_transaction_cancel(share_db)) {
 252                 smb_panic("transaction_cancel failed");
 253         }
 254
 255         return false;
 256 }
 257
 258 /*******************************************************************
 259  Fake up a Everyone, default access as a default.
 260  def_access is a GENERIC_XXX access mode.
 261  ********************************************************************/
 262
 263 struct security_descriptor *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32_t def_access)
 264 {
 265         uint32_t sa;
 266         struct security_ace ace;
 267         struct security_acl *psa = NULL;
 268         struct security_descriptor *psd = NULL;
 269         uint32_t spec_access = def_access;
 270
 271         se_map_generic(&spec_access, &file_generic_mapping);
 272
 273         sa = (def_access | spec_access );
 274         init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
 275
 276         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
 277                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 278                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 279                                     psa, psize);
 280         }
 281
 282         if (!psd) {
 283                 DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
 284                 return NULL;
 285         }
 286
 287         return psd;
 288 }
 289
 290 /*******************************************************************
 291  Pull a security descriptor from the share tdb.
 292  ********************************************************************/
 293
 294 struct security_descriptor *get_share_security( TALLOC_CTX *ctx, const char *servicename,
 295                               size_t *psize)
 296 {
 297         char *key;
 298         struct security_descriptor *psd = NULL;
 299         TDB_DATA data;
 300         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 301         NTSTATUS status;
 302
 303         if (!c_servicename) {
 304                 return NULL;
 305         }
 306
 307         if (!share_info_db_init()) {
 308                 TALLOC_FREE(c_servicename);
 309                 return NULL;
 310         }
 311
 312         if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {
 313                 TALLOC_FREE(c_servicename);
 314                 DEBUG(0, ("talloc_asprintf failed\n"));
 315                 return NULL;
 316         }
 317
 318         TALLOC_FREE(c_servicename);
 319
 320         status = dbwrap_fetch_bystring(share_db, talloc_tos(), key, &data);
 321
 322         TALLOC_FREE(key);
 323
 324         if (!NT_STATUS_IS_OK(status)) {
 325                 return get_share_security_default(ctx, psize,
 326                                                   SEC_RIGHTS_DIR_ALL);
 327         }
 328
 329         status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
 330
 331         TALLOC_FREE(data.dptr);
 332
 333         if (!NT_STATUS_IS_OK(status)) {
 334                 DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
 335                           nt_errstr(status)));
 336                 return get_share_security_default(ctx, psize,
 337                                                   SEC_RIGHTS_DIR_ALL);
 338         }
 339
 340         if (psd) {
 341                 *psize = ndr_size_security_descriptor(psd, 0);
 342         } else {
 343                 return get_share_security_default(ctx, psize,
 344                                                   SEC_RIGHTS_DIR_ALL);
 345         }
 346
 347         return psd;
 348 }
 349
 350 /*******************************************************************
 351  Store a security descriptor in the share db.
 352  ********************************************************************/
 353
 354 bool set_share_security(const char *share_name, struct security_descriptor *psd)
 355 {
 356         TALLOC_CTX *frame = talloc_stackframe();
 357         char *key;
 358         bool ret = False;
 359         TDB_DATA blob;
 360         NTSTATUS status;
 361         char *c_share_name = canonicalize_servicename(frame, share_name);
 362
 363         if (!c_share_name) {
 364                 goto out;
 365         }
 366
 367         if (!share_info_db_init()) {
 368                 goto out;
 369         }
 370
 371         status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
 372
 373         if (!NT_STATUS_IS_OK(status)) {
 374                 DEBUG(0, ("marshall_sec_desc failed: %s\n",
 375                           nt_errstr(status)));
 376                 goto out;
 377         }
 378
 379         if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {
 380                 DEBUG(0, ("talloc_asprintf failed\n"));
 381                 goto out;
 382         }
 383
 384         status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
 385                                     TDB_REPLACE);
 386         if (!NT_STATUS_IS_OK(status)) {
 387                 DEBUG(1, ("set_share_security: Failed to store secdesc for "
 388                           "%s: %s\n", share_name, nt_errstr(status)));
 389                 goto out;
 390         }
 391
 392         DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
 393         ret = True;
 394
 395  out:
 396         TALLOC_FREE(frame);
 397         return ret;
 398 }
 399
 400 /*******************************************************************
 401  Delete a security descriptor.
 402 ********************************************************************/
 403
 404 bool delete_share_security(const char *servicename)
 405 {
 406         TDB_DATA kbuf;
 407         char *key;
 408         NTSTATUS status;
 409         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 410
 411         if (!c_servicename) {
 412                 return NULL;
 413         }
 414
 415         if (!share_info_db_init()) {
 416                 TALLOC_FREE(c_servicename);
 417                 return False;
 418         }
 419
 420         if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 421                                     c_servicename))) {
 422                 TALLOC_FREE(c_servicename);
 423                 return False;
 424         }
 425         kbuf = string_term_tdb_data(key);
 426
 427         status = dbwrap_trans_delete(share_db, kbuf);
 428         if (!NT_STATUS_IS_OK(status)) {
 429                 DEBUG(0, ("delete_share_security: Failed to delete entry for "
 430                           "share %s: %s\n", c_servicename, nt_errstr(status)));
 431                 TALLOC_FREE(c_servicename);
 432                 return False;
 433         }
 434
 435         TALLOC_FREE(c_servicename);
 436         return True;
 437 }
 438
 439 /*******************************************************************
 440  Can this user access with share with the required permissions ?
 441 ********************************************************************/
 442
 443 bool share_access_check(const struct security_token *token,
 444                         const char *sharename,
 445                         uint32_t desired_access,
 446                         uint32_t *pgranted)
 447 {
 448         uint32_t granted;
 449         NTSTATUS status;
 450         struct security_descriptor *psd = NULL;
 451         size_t sd_size;
 452
 453         psd = get_share_security(talloc_tos(), sharename, &sd_size);
 454
 455         if (!psd) {
 456                 if (pgranted != NULL) {
 457                         *pgranted = desired_access;
 458                 }
 459                 return false;
 460         }
 461
 462         status = se_file_access_check(psd, token, true, desired_access, &granted);
 463
 464         TALLOC_FREE(psd);
 465
 466         if (pgranted != NULL) {
 467                 *pgranted = granted;
 468         }
 469
 470         return NT_STATUS_IS_OK(status);
 471 }
 472
 473 /***************************************************************************
 474  Parse the contents of an acl string from a usershare file.
 475 ***************************************************************************/
 476
 477 bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, struct security_descriptor **ppsd)
 478 {
 479         size_t s_size = 0;
 480         const char *pacl = acl_str;
 481         int num_aces = 0;
 482         struct security_ace *ace_list = NULL;
 483         struct security_acl *psa = NULL;
 484         struct security_descriptor *psd = NULL;
 485         size_t sd_size = 0;
 486         int i;
 487
 488         *ppsd = NULL;
 489
 490         /* If the acl string is blank return "Everyone:R" */
 491         if (!*acl_str) {
 492                 struct security_descriptor *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
 493                 if (!default_psd) {
 494                         return False;
 495                 }
 496                 *ppsd = default_psd;
 497                 return True;
 498         }
 499
 500         num_aces = 1;
 501
 502         /* Add the number of ',' characters to get the number of aces. */
 503         num_aces += count_chars(pacl,',');
 504
 505         ace_list = talloc_array(ctx, struct security_ace, num_aces);
 506         if (!ace_list) {
 507                 return False;
 508         }
 509
 510         for (i = 0; i < num_aces; i++) {
 511                 uint32_t sa;
 512                 uint32_t g_access;
 513                 uint32_t s_access;
 514                 struct dom_sid sid;
 515                 char *sidstr;
 516                 enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
 517
 518                 if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
 519                         DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
 520                                 "for ':' in string '%s'\n", pacl));
 521                         return False;
 522                 }
 523
 524                 if (!string_to_sid(&sid, sidstr)) {
 525                         DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
 526                                 sidstr ));
 527                         return False;
 528                 }
 529
 530                 switch (*pacl) {
 531                         case 'F': /* Full Control, ie. R+W */
 532                         case 'f': /* Full Control, ie. R+W */
 533                                 s_access = g_access = GENERIC_ALL_ACCESS;
 534                                 break;
 535                         case 'R': /* Read only. */
 536                         case 'r': /* Read only. */
 537                                 s_access = g_access = GENERIC_READ_ACCESS;
 538                                 break;
 539                         case 'D': /* Deny all to this SID. */
 540                         case 'd': /* Deny all to this SID. */
 541                                 type = SEC_ACE_TYPE_ACCESS_DENIED;
 542                                 s_access = g_access = GENERIC_ALL_ACCESS;
 543                                 break;
 544                         default:
 545                                 DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
 546                                         pacl ));
 547                                 return False;
 548                 }
 549
 550                 pacl++;
 551                 if (*pacl && *pacl != ',') {
 552                         DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
 553                                 pacl ));
 554                         return False;
 555                 }
 556                 pacl++; /* Go past any ',' */
 557
 558                 se_map_generic(&s_access, &file_generic_mapping);
 559                 sa = (g_access | s_access);
 560                 init_sec_ace(&ace_list[i], &sid, type, sa, 0);
 561         }
 562
 563         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
 564                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 565                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 566                                     psa, &sd_size);
 567         }
 568
 569         if (!psd) {
 570                 DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
 571                 return False;
 572         }
 573
 574         *ppsd = psd;
 575         return True;
 576 }