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
 146         if (share_db != NULL) {
 147                 return True;
 148         }
 149
 150         share_db = db_open(NULL, state_path("share_info.tdb"), 0,
 151                                  TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
 152         if (share_db == NULL) {
 153                 DEBUG(0,("Failed to open share info database %s (%s)\n",
 154                         state_path("share_info.tdb"), strerror(errno) ));
 155                 return False;
 156         }
 157
 158         status = dbwrap_fetch_int32(share_db, vstring, &vers_id);
 159         if (!NT_STATUS_IS_OK(status)) {
 160                 vers_id = 0;
 161         }
 162
 163         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 164                 return true;
 165         }
 166
 167         if (dbwrap_transaction_start(share_db) != 0) {
 168                 DEBUG(0, ("transaction_start failed\n"));
 169                 TALLOC_FREE(share_db);
 170                 return false;
 171         }
 172
 173         status = dbwrap_fetch_int32(share_db, vstring, &vers_id);
 174         if (!NT_STATUS_IS_OK(status)) {
 175                 vers_id = 0;
 176         }
 177
 178         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 179                 /*
 180                  * Race condition
 181                  */
 182                 if (dbwrap_transaction_cancel(share_db)) {
 183                         smb_panic("transaction_cancel failed");
 184                 }
 185                 return true;
 186         }
 187
 188         /* Move to at least V2. */
 189
 190         /* Cope with byte-reversed older versions of the db. */
 191         if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
 192                 /* Written on a bigendian machine with old fetch_int code. Save as le. */
 193
 194                 status = dbwrap_store_int32(share_db, vstring,
 195                                             SHARE_DATABASE_VERSION_V2);
 196                 if (!NT_STATUS_IS_OK(status)) {
 197                         DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 198                                   nt_errstr(status)));
 199                         goto cancel;
 200                 }
 201                 vers_id = SHARE_DATABASE_VERSION_V2;
 202         }
 203
 204         if (vers_id != SHARE_DATABASE_VERSION_V2) {
 205                 status = dbwrap_traverse(share_db, delete_fn, NULL, NULL);
 206                 if (!NT_STATUS_IS_OK(status)) {
 207                         DEBUG(0, ("traverse failed\n"));
 208                         goto cancel;
 209                 }
 210                 status = dbwrap_store_int32(share_db, vstring,
 211                                             SHARE_DATABASE_VERSION_V2);
 212                 if (!NT_STATUS_IS_OK(status)) {
 213                         DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 214                                   nt_errstr(status)));
 215                         goto cancel;
 216                 }
 217         }
 218
 219         /* Finally upgrade to version 3, with canonicalized sharenames. */
 220
 221         status = dbwrap_traverse(share_db, upgrade_v2_to_v3, &upgrade_ok, NULL);
 222         if (!NT_STATUS_IS_OK(status) || upgrade_ok == false) {
 223                 DEBUG(0, ("traverse failed\n"));
 224                 goto cancel;
 225         }
 226         status = dbwrap_store_int32(share_db, vstring,
 227                                     SHARE_DATABASE_VERSION_V3);
 228         if (!NT_STATUS_IS_OK(status)) {
 229                 DEBUG(0, ("dbwrap_store_int32 failed: %s\n",
 230                           nt_errstr(status)));
 231                 goto cancel;
 232         }
 233
 234         if (dbwrap_transaction_commit(share_db) != 0) {
 235                 DEBUG(0, ("transaction_commit failed\n"));
 236                 return false;
 237         }
 238
 239         return true;
 240
 241  cancel:
 242         if (dbwrap_transaction_cancel(share_db)) {
 243                 smb_panic("transaction_cancel failed");
 244         }
 245
 246         return false;
 247 }
 248
 249 /*******************************************************************
 250  Fake up a Everyone, default access as a default.
 251  def_access is a GENERIC_XXX access mode.
 252  ********************************************************************/
 253
 254 struct security_descriptor *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32 def_access)
 255 {
 256         uint32_t sa;
 257         struct security_ace ace;
 258         struct security_acl *psa = NULL;
 259         struct security_descriptor *psd = NULL;
 260         uint32 spec_access = def_access;
 261
 262         se_map_generic(&spec_access, &file_generic_mapping);
 263
 264         sa = (def_access | spec_access );
 265         init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
 266
 267         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
 268                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 269                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 270                                     psa, psize);
 271         }
 272
 273         if (!psd) {
 274                 DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
 275                 return NULL;
 276         }
 277
 278         return psd;
 279 }
 280
 281 /*******************************************************************
 282  Pull a security descriptor from the share tdb.
 283  ********************************************************************/
 284
 285 struct security_descriptor *get_share_security( TALLOC_CTX *ctx, const char *servicename,
 286                               size_t *psize)
 287 {
 288         char *key;
 289         struct security_descriptor *psd = NULL;
 290         TDB_DATA data;
 291         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 292         NTSTATUS status;
 293
 294         if (!c_servicename) {
 295                 return NULL;
 296         }
 297
 298         if (!share_info_db_init()) {
 299                 TALLOC_FREE(c_servicename);
 300                 return NULL;
 301         }
 302
 303         if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {
 304                 TALLOC_FREE(c_servicename);
 305                 DEBUG(0, ("talloc_asprintf failed\n"));
 306                 return NULL;
 307         }
 308
 309         TALLOC_FREE(c_servicename);
 310
 311         status = dbwrap_fetch_bystring(share_db, talloc_tos(), key, &data);
 312
 313         TALLOC_FREE(key);
 314
 315         if (!NT_STATUS_IS_OK(status)) {
 316                 return get_share_security_default(ctx, psize,
 317                                                   SEC_RIGHTS_DIR_ALL);
 318         }
 319
 320         status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
 321
 322         TALLOC_FREE(data.dptr);
 323
 324         if (!NT_STATUS_IS_OK(status)) {
 325                 DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
 326                           nt_errstr(status)));
 327                 return get_share_security_default(ctx, psize,
 328                                                   SEC_RIGHTS_DIR_ALL);
 329         }
 330
 331         if (psd) {
 332                 *psize = ndr_size_security_descriptor(psd, 0);
 333         } else {
 334                 return get_share_security_default(ctx, psize,
 335                                                   SEC_RIGHTS_DIR_ALL);
 336         }
 337
 338         return psd;
 339 }
 340
 341 /*******************************************************************
 342  Store a security descriptor in the share db.
 343  ********************************************************************/
 344
 345 bool set_share_security(const char *share_name, struct security_descriptor *psd)
 346 {
 347         TALLOC_CTX *frame = talloc_stackframe();
 348         char *key;
 349         bool ret = False;
 350         TDB_DATA blob;
 351         NTSTATUS status;
 352         char *c_share_name = canonicalize_servicename(frame, share_name);
 353
 354         if (!c_share_name) {
 355                 goto out;
 356         }
 357
 358         if (!share_info_db_init()) {
 359                 goto out;
 360         }
 361
 362         status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
 363
 364         if (!NT_STATUS_IS_OK(status)) {
 365                 DEBUG(0, ("marshall_sec_desc failed: %s\n",
 366                           nt_errstr(status)));
 367                 goto out;
 368         }
 369
 370         if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {
 371                 DEBUG(0, ("talloc_asprintf failed\n"));
 372                 goto out;
 373         }
 374
 375         status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
 376                                     TDB_REPLACE);
 377         if (!NT_STATUS_IS_OK(status)) {
 378                 DEBUG(1, ("set_share_security: Failed to store secdesc for "
 379                           "%s: %s\n", share_name, nt_errstr(status)));
 380                 goto out;
 381         }
 382
 383         DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
 384         ret = True;
 385
 386  out:
 387         TALLOC_FREE(frame);
 388         return ret;
 389 }
 390
 391 /*******************************************************************
 392  Delete a security descriptor.
 393 ********************************************************************/
 394
 395 bool delete_share_security(const char *servicename)
 396 {
 397         TDB_DATA kbuf;
 398         char *key;
 399         NTSTATUS status;
 400         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 401
 402         if (!c_servicename) {
 403                 return NULL;
 404         }
 405
 406         if (!share_info_db_init()) {
 407                 TALLOC_FREE(c_servicename);
 408                 return False;
 409         }
 410
 411         if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 412                                     c_servicename))) {
 413                 TALLOC_FREE(c_servicename);
 414                 return False;
 415         }
 416         kbuf = string_term_tdb_data(key);
 417
 418         status = dbwrap_trans_delete(share_db, kbuf);
 419         if (!NT_STATUS_IS_OK(status)) {
 420                 DEBUG(0, ("delete_share_security: Failed to delete entry for "
 421                           "share %s: %s\n", c_servicename, nt_errstr(status)));
 422                 TALLOC_FREE(c_servicename);
 423                 return False;
 424         }
 425
 426         TALLOC_FREE(c_servicename);
 427         return True;
 428 }
 429
 430 /*******************************************************************
 431  Can this user access with share with the required permissions ?
 432 ********************************************************************/
 433
 434 bool share_access_check(const struct security_token *token,
 435                         const char *sharename,
 436                         uint32 desired_access,
 437                         uint32_t *pgranted)
 438 {
 439         uint32 granted;
 440         NTSTATUS status;
 441         struct security_descriptor *psd = NULL;
 442         size_t sd_size;
 443
 444         psd = get_share_security(talloc_tos(), sharename, &sd_size);
 445
 446         if (!psd) {
 447                 if (pgranted != NULL) {
 448                         *pgranted = desired_access;
 449                 }
 450                 return false;
 451         }
 452
 453         status = se_access_check(psd, token, desired_access, &granted);
 454
 455         TALLOC_FREE(psd);
 456
 457         if (pgranted != NULL) {
 458                 *pgranted = granted;
 459         }
 460
 461         return NT_STATUS_IS_OK(status);
 462 }
 463
 464 /***************************************************************************
 465  Parse the contents of an acl string from a usershare file.
 466 ***************************************************************************/
 467
 468 bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, struct security_descriptor **ppsd)
 469 {
 470         size_t s_size = 0;
 471         const char *pacl = acl_str;
 472         int num_aces = 0;
 473         struct security_ace *ace_list = NULL;
 474         struct security_acl *psa = NULL;
 475         struct security_descriptor *psd = NULL;
 476         size_t sd_size = 0;
 477         int i;
 478
 479         *ppsd = NULL;
 480
 481         /* If the acl string is blank return "Everyone:R" */
 482         if (!*acl_str) {
 483                 struct security_descriptor *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
 484                 if (!default_psd) {
 485                         return False;
 486                 }
 487                 *ppsd = default_psd;
 488                 return True;
 489         }
 490
 491         num_aces = 1;
 492
 493         /* Add the number of ',' characters to get the number of aces. */
 494         num_aces += count_chars(pacl,',');
 495
 496         ace_list = talloc_array(ctx, struct security_ace, num_aces);
 497         if (!ace_list) {
 498                 return False;
 499         }
 500
 501         for (i = 0; i < num_aces; i++) {
 502                 uint32_t sa;
 503                 uint32 g_access;
 504                 uint32 s_access;
 505                 struct dom_sid sid;
 506                 char *sidstr;
 507                 enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
 508
 509                 if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
 510                         DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
 511                                 "for ':' in string '%s'\n", pacl));
 512                         return False;
 513                 }
 514
 515                 if (!string_to_sid(&sid, sidstr)) {
 516                         DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
 517                                 sidstr ));
 518                         return False;
 519                 }
 520
 521                 switch (*pacl) {
 522                         case 'F': /* Full Control, ie. R+W */
 523                         case 'f': /* Full Control, ie. R+W */
 524                                 s_access = g_access = GENERIC_ALL_ACCESS;
 525                                 break;
 526                         case 'R': /* Read only. */
 527                         case 'r': /* Read only. */
 528                                 s_access = g_access = GENERIC_READ_ACCESS;
 529                                 break;
 530                         case 'D': /* Deny all to this SID. */
 531                         case 'd': /* Deny all to this SID. */
 532                                 type = SEC_ACE_TYPE_ACCESS_DENIED;
 533                                 s_access = g_access = GENERIC_ALL_ACCESS;
 534                                 break;
 535                         default:
 536                                 DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
 537                                         pacl ));
 538                                 return False;
 539                 }
 540
 541                 pacl++;
 542                 if (*pacl && *pacl != ',') {
 543                         DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
 544                                 pacl ));
 545                         return False;
 546                 }
 547                 pacl++; /* Go past any ',' */
 548
 549                 se_map_generic(&s_access, &file_generic_mapping);
 550                 sa = (g_access | s_access);
 551                 init_sec_ace(&ace_list[i], &sid, type, sa, 0);
 552         }
 553
 554         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
 555                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 556                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 557                                     psa, &sd_size);
 558         }
 559
 560         if (!psd) {
 561                 DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
 562                 return False;
 563         }
 564
 565         *ppsd = psd;
 566         return True;
 567 }