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 #include "libcli/util/ntstatus.h"
  28
  29 /*******************************************************************
  30  Create the share security tdb.
  31  ********************************************************************/
  32
  33 static struct db_context *share_db; /* used for share security descriptors */
  34 #define SHARE_DATABASE_VERSION_V1 1
  35 #define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */
  36 #define SHARE_DATABASE_VERSION_V3 3 /* canonicalized sharenames as lower case */
  37
  38 #define SHARE_SECURITY_DB_KEY_PREFIX_STR "SECDESC/"
  39 /* Map generic permissions to file object specific permissions */
  40
  41 extern const struct generic_mapping file_generic_mapping;
  42
  43 static int delete_fn(struct db_record *rec, void *priv)
  44 {
  45         dbwrap_record_delete(rec);
  46         return 0;
  47 }
  48
  49 /*****************************************************
  50  Looking for keys of the form: SHARE_SECURITY_DB_KEY_PREFIX_STR + "non lower case str".
  51  If we find one re-write it into a canonical case form.
  52 *****************************************************/
  53
  54 static int upgrade_v2_to_v3(struct db_record *rec, void *priv)
  55 {
  56         size_t prefix_len = strlen(SHARE_SECURITY_DB_KEY_PREFIX_STR);
  57         const char *servicename = NULL;
  58         char *c_servicename = NULL;
  59         char *newkey = NULL;
  60         bool *p_upgrade_ok = (bool *)priv;
  61         NTSTATUS status;
  62         TDB_DATA key;
  63         TDB_DATA value;
  64
  65         key = dbwrap_record_get_key(rec);
  66
  67         /* Is there space for a one character sharename ? */
  68         if (key.dsize <= prefix_len+2) {
  69                 return 0;
  70         }
  71
  72         /* Does it start with the share key prefix ? */
  73         if (memcmp(key.dptr, SHARE_SECURITY_DB_KEY_PREFIX_STR,
  74                         prefix_len) != 0) {
  75                 return 0;
  76         }
  77
  78         /* Is it a null terminated string as a key ? */
  79         if (key.dptr[key.dsize-1] != '\0') {
  80                 return 0;
  81         }
  82
  83         /* Bytes after the prefix are the sharename string. */
  84         servicename = (char *)&key.dptr[prefix_len];
  85         c_servicename = canonicalize_servicename(talloc_tos(), servicename);
  86         if (!c_servicename) {
  87                 smb_panic("out of memory upgrading share security db from v2 -> v3");
  88         }
  89
  90         if (strcmp(servicename, c_servicename) == 0) {
  91                 /* Old and new names match. No canonicalization needed. */
  92                 TALLOC_FREE(c_servicename);
  93                 return 0;
  94         }
  95
  96         /* Oops. Need to canonicalize name, delete old then store new. */
  97         status = dbwrap_record_delete(rec);
  98         if (!NT_STATUS_IS_OK(status)) {
  99                 DEBUG(1, ("upgrade_v2_to_v3: Failed to delete secdesc for "
 100                           "%s: %s\n", (const char *)key.dptr,
 101                           nt_errstr(status)));
 102                 TALLOC_FREE(c_servicename);
 103                 *p_upgrade_ok = false;
 104                 return -1;
 105         } else {
 106                 DEBUG(10, ("upgrade_v2_to_v3: deleted secdesc for "
 107                           "%s\n", (const char *)key.dptr));
 108         }
 109
 110         if (!(newkey = talloc_asprintf(talloc_tos(),
 111                         SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 112                         c_servicename))) {
 113                 smb_panic("out of memory upgrading share security db from v2 -> v3");
 114         }
 115
 116         value = dbwrap_record_get_value(rec);
 117         status = dbwrap_store(share_db,
 118                                 string_term_tdb_data(newkey),
 119                                 value,
 120                                 TDB_REPLACE);
 121
 122         if (!NT_STATUS_IS_OK(status)) {
 123                 DEBUG(1, ("upgrade_v2_to_v3: Failed to store secdesc for "
 124                           "%s: %s\n", c_servicename, nt_errstr(status)));
 125                 TALLOC_FREE(c_servicename);
 126                 TALLOC_FREE(newkey);
 127                 *p_upgrade_ok = false;
 128                 return -1;
 129         } else {
 130                 DEBUG(10, ("upgrade_v2_to_v3: stored secdesc for "
 131                           "%s\n", newkey ));
 132         }
 133
 134         TALLOC_FREE(newkey);
 135         TALLOC_FREE(c_servicename);
 136
 137         return 0;
 138 }
 139
 140 NTSTATUS share_info_db_init(void)
 141 {
 142         const char *vstring = "INFO/version";
 143         int32_t vers_id = 0;
 144         bool upgrade_ok = true;
 145         NTSTATUS status;
 146         char *db_path;
 147
 148         if (share_db != NULL) {
 149                 return NT_STATUS_OK;
 150         }
 151
 152         db_path = state_path(talloc_tos(), "share_info.tdb");
 153         if (db_path == NULL) {
 154                 return NT_STATUS_NO_MEMORY;
 155         }
 156
 157         share_db = db_open(NULL, db_path, 0,
 158                            TDB_DEFAULT, O_RDWR|O_CREAT, 0600,
 159                            DBWRAP_LOCK_ORDER_1, DBWRAP_FLAG_NONE);
 160         if (share_db == NULL) {
 161                 DEBUG(0,("Failed to open share info database %s (%s)\n",
 162                          db_path, strerror(errno)));
 163                 TALLOC_FREE(db_path);
 164                 return map_nt_error_from_unix_common(errno);
 165         }
 166         TALLOC_FREE(db_path);
 167
 168         status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);
 169         if (!NT_STATUS_IS_OK(status)) {
 170                 vers_id = 0;
 171         }
 172
 173         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 174                 return NT_STATUS_OK;
 175         }
 176
 177         if (dbwrap_transaction_start(share_db) != 0) {
 178                 DEBUG(0, ("transaction_start failed\n"));
 179                 TALLOC_FREE(share_db);
 180                 return NT_STATUS_INTERNAL_DB_ERROR;
 181         }
 182
 183         status = dbwrap_fetch_int32_bystring(share_db, vstring, &vers_id);
 184         if (!NT_STATUS_IS_OK(status)) {
 185                 vers_id = 0;
 186         }
 187
 188         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 189                 /*
 190                  * Race condition
 191                  */
 192                 if (dbwrap_transaction_cancel(share_db)) {
 193                         smb_panic("transaction_cancel failed");
 194                 }
 195                 return NT_STATUS_OK;
 196         }
 197
 198         /* Move to at least V2. */
 199
 200         /* Cope with byte-reversed older versions of the db. */
 201         if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
 202                 /* Written on a bigendian machine with old fetch_int code. Save as le. */
 203
 204                 status = dbwrap_store_int32_bystring(
 205                         share_db, vstring, SHARE_DATABASE_VERSION_V2);
 206                 if (!NT_STATUS_IS_OK(status)) {
 207                         DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 208                                   nt_errstr(status)));
 209                         goto cancel;
 210                 }
 211                 vers_id = SHARE_DATABASE_VERSION_V2;
 212         }
 213
 214         if (vers_id != SHARE_DATABASE_VERSION_V2) {
 215                 status = dbwrap_traverse(share_db, delete_fn, NULL, NULL);
 216                 if (!NT_STATUS_IS_OK(status)) {
 217                         DEBUG(0, ("traverse failed\n"));
 218                         goto cancel;
 219                 }
 220                 status = dbwrap_store_int32_bystring(
 221                         share_db, vstring, SHARE_DATABASE_VERSION_V2);
 222                 if (!NT_STATUS_IS_OK(status)) {
 223                         DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 224                                   nt_errstr(status)));
 225                         goto cancel;
 226                 }
 227         }
 228
 229         /* Finally upgrade to version 3, with canonicalized sharenames. */
 230
 231         status = dbwrap_traverse(share_db, upgrade_v2_to_v3, &upgrade_ok, NULL);
 232         if (!NT_STATUS_IS_OK(status)) {
 233                 DEBUG(0, ("traverse failed\n"));
 234                 goto cancel;
 235         }
 236         if (!upgrade_ok) {
 237                 DBG_ERR("upgrade failed.\n");
 238                 status = NT_STATUS_INTERNAL_ERROR;
 239                 goto cancel;
 240         }
 241
 242         status = dbwrap_store_int32_bystring(
 243                 share_db, vstring, SHARE_DATABASE_VERSION_V3);
 244         if (!NT_STATUS_IS_OK(status)) {
 245                 DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 246                           nt_errstr(status)));
 247                 goto cancel;
 248         }
 249
 250         if (dbwrap_transaction_commit(share_db) != 0) {
 251                 DEBUG(0, ("transaction_commit failed\n"));
 252                 return NT_STATUS_INTERNAL_ERROR;
 253         }
 254
 255         return NT_STATUS_OK;
 256
 257  cancel:
 258         if (dbwrap_transaction_cancel(share_db)) {
 259                 smb_panic("transaction_cancel failed");
 260         }
 261
 262         return status;
 263 }
 264
 265 /*******************************************************************
 266  Fake up a Everyone, default access as a default.
 267  def_access is a GENERIC_XXX access mode.
 268  ********************************************************************/
 269
 270 struct security_descriptor *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32_t def_access)
 271 {
 272         uint32_t sa;
 273         struct security_ace ace;
 274         struct security_acl *psa = NULL;
 275         struct security_descriptor *psd = NULL;
 276         uint32_t spec_access = def_access;
 277
 278         se_map_generic(&spec_access, &file_generic_mapping);
 279
 280         sa = (def_access | spec_access );
 281         init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
 282
 283         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
 284                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 285                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 286                                     psa, psize);
 287         }
 288
 289         if (!psd) {
 290                 DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
 291                 return NULL;
 292         }
 293
 294         return psd;
 295 }
 296
 297 /*******************************************************************
 298  Pull a security descriptor from the share tdb.
 299  ********************************************************************/
 300
 301 struct security_descriptor *get_share_security( TALLOC_CTX *ctx, const char *servicename,
 302                               size_t *psize)
 303 {
 304         char *key;
 305         struct security_descriptor *psd = NULL;
 306         TDB_DATA data;
 307         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 308         NTSTATUS status;
 309
 310         if (!c_servicename) {
 311                 return NULL;
 312         }
 313
 314         status = share_info_db_init();
 315         if (!NT_STATUS_IS_OK(status)) {
 316                 TALLOC_FREE(c_servicename);
 317                 return NULL;
 318         }
 319
 320         if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {
 321                 TALLOC_FREE(c_servicename);
 322                 DEBUG(0, ("talloc_asprintf failed\n"));
 323                 return NULL;
 324         }
 325
 326         TALLOC_FREE(c_servicename);
 327
 328         status = dbwrap_fetch_bystring(share_db, talloc_tos(), key, &data);
 329
 330         TALLOC_FREE(key);
 331
 332         if (!NT_STATUS_IS_OK(status)) {
 333                 return get_share_security_default(ctx, psize,
 334                                                   SEC_RIGHTS_DIR_ALL);
 335         }
 336
 337         status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
 338
 339         TALLOC_FREE(data.dptr);
 340
 341         if (!NT_STATUS_IS_OK(status)) {
 342                 return get_share_security_default(ctx, psize,
 343                                                   SEC_RIGHTS_DIR_ALL);
 344         }
 345
 346         if (psd) {
 347                 *psize = ndr_size_security_descriptor(psd, 0);
 348         } else {
 349                 return get_share_security_default(ctx, psize,
 350                                                   SEC_RIGHTS_DIR_ALL);
 351         }
 352
 353         return psd;
 354 }
 355
 356 /*******************************************************************
 357  Store a security descriptor in the share db.
 358  ********************************************************************/
 359
 360 NTSTATUS set_share_security(const char *share_name,
 361                             struct security_descriptor *psd)
 362 {
 363         TALLOC_CTX *frame = talloc_stackframe();
 364         char *key;
 365         TDB_DATA blob;
 366         NTSTATUS status;
 367         char *c_share_name = canonicalize_servicename(frame, share_name);
 368
 369         if (c_share_name == NULL) {
 370                 status = NT_STATUS_INVALID_PARAMETER;
 371                 goto out;
 372         }
 373
 374         status = share_info_db_init();
 375         if (!NT_STATUS_IS_OK(status)) {
 376                 goto out;
 377         }
 378
 379         status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
 380
 381         if (!NT_STATUS_IS_OK(status)) {
 382                 DEBUG(0, ("marshall_sec_desc failed: %s\n",
 383                           nt_errstr(status)));
 384                 goto out;
 385         }
 386
 387         if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {
 388                 DEBUG(0, ("talloc_asprintf failed\n"));
 389                 status = NT_STATUS_NO_MEMORY;
 390                 goto out;
 391         }
 392
 393         status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
 394                                     TDB_REPLACE);
 395         if (!NT_STATUS_IS_OK(status)) {
 396                 DEBUG(1, ("set_share_security: Failed to store secdesc for "
 397                           "%s: %s\n", share_name, nt_errstr(status)));
 398                 goto out;
 399         }
 400
 401         DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
 402         status = NT_STATUS_OK;
 403
 404  out:
 405         TALLOC_FREE(frame);
 406         return status;
 407 }
 408
 409 /*******************************************************************
 410  Delete a security descriptor.
 411 ********************************************************************/
 412
 413 NTSTATUS delete_share_security(const char *servicename)
 414 {
 415         TDB_DATA kbuf;
 416         char *key;
 417         NTSTATUS status;
 418         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 419
 420         if (c_servicename == NULL) {
 421                 return NT_STATUS_INVALID_PARAMETER;
 422         }
 423
 424         status = share_info_db_init();
 425         if (!NT_STATUS_IS_OK(status)) {
 426                 TALLOC_FREE(c_servicename);
 427                 return status;
 428         }
 429
 430         if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 431                                     c_servicename))) {
 432                 TALLOC_FREE(c_servicename);
 433                 return NT_STATUS_NO_MEMORY;
 434         }
 435         kbuf = string_term_tdb_data(key);
 436
 437         status = dbwrap_trans_delete(share_db, kbuf);
 438         if (!NT_STATUS_IS_OK(status)) {
 439                 DEBUG(0, ("delete_share_security: Failed to delete entry for "
 440                           "share %s: %s\n", c_servicename, nt_errstr(status)));
 441                 TALLOC_FREE(c_servicename);
 442                 return status;
 443         }
 444
 445         TALLOC_FREE(c_servicename);
 446         return NT_STATUS_OK;
 447 }
 448
 449 /*******************************************************************
 450  Can this user access with share with the required permissions ?
 451 ********************************************************************/
 452
 453 bool share_access_check(const struct security_token *token,
 454                         const char *sharename,
 455                         uint32_t desired_access,
 456                         uint32_t *pgranted)
 457 {
 458         uint32_t granted;
 459         NTSTATUS status;
 460         struct security_descriptor *psd = NULL;
 461         size_t sd_size;
 462
 463         psd = get_share_security(talloc_tos(), sharename, &sd_size);
 464
 465         if (!psd) {
 466                 if (pgranted != NULL) {
 467                         *pgranted = desired_access;
 468                 }
 469                 return false;
 470         }
 471
 472         status = se_file_access_check(psd, token, true, desired_access, &granted);
 473
 474         TALLOC_FREE(psd);
 475
 476         if (pgranted != NULL) {
 477                 *pgranted = granted;
 478         }
 479
 480         return NT_STATUS_IS_OK(status);
 481 }
 482
 483 /***************************************************************************
 484  Parse the contents of an acl string from a usershare file.
 485 ***************************************************************************/
 486
 487 bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, struct security_descriptor **ppsd)
 488 {
 489         size_t s_size = 0;
 490         const char *pacl = acl_str;
 491         int num_aces = 0;
 492         struct security_ace *ace_list = NULL;
 493         struct security_acl *psa = NULL;
 494         struct security_descriptor *psd = NULL;
 495         size_t sd_size = 0;
 496         int i;
 497
 498         *ppsd = NULL;
 499
 500         /* If the acl string is blank return "Everyone:R" */
 501         if (!*acl_str) {
 502                 struct security_descriptor *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
 503                 if (!default_psd) {
 504                         return False;
 505                 }
 506                 *ppsd = default_psd;
 507                 return True;
 508         }
 509
 510         num_aces = 1;
 511
 512         /* Add the number of ',' characters to get the number of aces. */
 513         num_aces += count_chars(pacl,',');
 514
 515         ace_list = talloc_array(ctx, struct security_ace, num_aces);
 516         if (!ace_list) {
 517                 return False;
 518         }
 519
 520         for (i = 0; i < num_aces; i++) {
 521                 uint32_t sa;
 522                 uint32_t g_access;
 523                 uint32_t s_access;
 524                 struct dom_sid sid;
 525                 char *sidstr;
 526                 enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
 527
 528                 if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
 529                         DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
 530                                 "for ':' in string '%s'\n", pacl));
 531                         return False;
 532                 }
 533
 534                 if (!string_to_sid(&sid, sidstr)) {
 535                         DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
 536                                 sidstr ));
 537                         return False;
 538                 }
 539
 540                 switch (*pacl) {
 541                         case 'F': /* Full Control, ie. R+W */
 542                         case 'f': /* Full Control, ie. R+W */
 543                                 s_access = g_access = GENERIC_ALL_ACCESS;
 544                                 break;
 545                         case 'R': /* Read only. */
 546                         case 'r': /* Read only. */
 547                                 s_access = g_access = GENERIC_READ_ACCESS;
 548                                 break;
 549                         case 'D': /* Deny all to this SID. */
 550                         case 'd': /* Deny all to this SID. */
 551                                 type = SEC_ACE_TYPE_ACCESS_DENIED;
 552                                 s_access = g_access = GENERIC_ALL_ACCESS;
 553                                 break;
 554                         default:
 555                                 DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
 556                                         pacl ));
 557                                 return False;
 558                 }
 559
 560                 pacl++;
 561                 if (*pacl && *pacl != ',') {
 562                         DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
 563                                 pacl ));
 564                         return False;
 565                 }
 566                 pacl++; /* Go past any ',' */
 567
 568                 se_map_generic(&s_access, &file_generic_mapping);
 569                 sa = (g_access | s_access);
 570                 init_sec_ace(&ace_list[i], &sid, type, sa, 0);
 571         }
 572
 573         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
 574                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 575                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 576                                     psa, &sd_size);
 577         }
 578
 579         if (!psd) {
 580                 DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
 581                 return False;
 582         }
 583
 584         *ppsd = psd;
 585         return True;
 586 }