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 "../librpc/gen_ndr/ndr_security.h"
  22 #include "dbwrap.h"
  23
  24 /*******************************************************************
  25  Create the share security tdb.
  26  ********************************************************************/
  27
  28 static struct db_context *share_db; /* used for share security descriptors */
  29 #define SHARE_DATABASE_VERSION_V1 1
  30 #define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */
  31 #define SHARE_DATABASE_VERSION_V3 3 /* canonicalized sharenames as lower case */
  32
  33 #define SHARE_SECURITY_DB_KEY_PREFIX_STR "SECDESC/"
  34 /* Map generic permissions to file object specific permissions */
  35
  36 extern const struct generic_mapping file_generic_mapping;
  37
  38 static int delete_fn(struct db_record *rec, void *priv)
  39 {
  40         rec->delete_rec(rec);
  41         return 0;
  42 }
  43
  44 /*****************************************************
  45  Looking for keys of the form: SHARE_SECURITY_DB_KEY_PREFIX_STR + "non lower case str".
  46  If we find one re-write it into a canonical case form.
  47 *****************************************************/
  48
  49 static int upgrade_v2_to_v3(struct db_record *rec, void *priv)
  50 {
  51         size_t prefix_len = strlen(SHARE_SECURITY_DB_KEY_PREFIX_STR);
  52         const char *servicename = NULL;
  53         char *c_servicename = NULL;
  54         char *newkey = NULL;
  55         bool *p_upgrade_ok = (bool *)priv;
  56         NTSTATUS status;
  57
  58         /* Is there space for a one character sharename ? */
  59         if (rec->key.dsize <= prefix_len+2) {
  60                 return 0;
  61         }
  62
  63         /* Does it start with the share key prefix ? */
  64         if (memcmp(rec->key.dptr, SHARE_SECURITY_DB_KEY_PREFIX_STR,
  65                         prefix_len) != 0) {
  66                 return 0;
  67         }
  68
  69         /* Is it a null terminated string as a key ? */
  70         if (rec->key.dptr[rec->key.dsize-1] != '\0') {
  71                 return 0;
  72         }
  73
  74         /* Bytes after the prefix are the sharename string. */
  75         servicename = (char *)&rec->key.dptr[prefix_len];
  76         c_servicename = canonicalize_servicename(talloc_tos(), servicename);
  77         if (!c_servicename) {
  78                 smb_panic("out of memory upgrading share security db from v2 -> v3");
  79         }
  80
  81         if (strcmp(servicename, c_servicename) == 0) {
  82                 /* Old and new names match. No canonicalization needed. */
  83                 TALLOC_FREE(c_servicename);
  84                 return 0;
  85         }
  86
  87         /* Oops. Need to canonicalize name, delete old then store new. */
  88         status = rec->delete_rec(rec);
  89         if (!NT_STATUS_IS_OK(status)) {
  90                 DEBUG(1, ("upgrade_v2_to_v3: Failed to delete secdesc for "
  91                           "%s: %s\n", rec->key.dptr, nt_errstr(status)));
  92                 TALLOC_FREE(c_servicename);
  93                 *p_upgrade_ok = false;
  94                 return -1;
  95         } else {
  96                 DEBUG(10, ("upgrade_v2_to_v3: deleted secdesc for "
  97                           "%s\n", rec->key.dptr ));
  98         }
  99
 100         if (!(newkey = talloc_asprintf(talloc_tos(),
 101                         SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 102                         c_servicename))) {
 103                 smb_panic("out of memory upgrading share security db from v2 -> v3");
 104         }
 105
 106         status = dbwrap_store(share_db,
 107                                 string_term_tdb_data(newkey),
 108                                 rec->value,
 109                                 TDB_REPLACE);
 110
 111         if (!NT_STATUS_IS_OK(status)) {
 112                 DEBUG(1, ("upgrade_v2_to_v3: Failed to store secdesc for "
 113                           "%s: %s\n", c_servicename, nt_errstr(status)));
 114                 TALLOC_FREE(c_servicename);
 115                 TALLOC_FREE(newkey);
 116                 *p_upgrade_ok = false;
 117                 return -1;
 118         } else {
 119                 DEBUG(10, ("upgrade_v2_to_v3: stored secdesc for "
 120                           "%s\n", newkey ));
 121         }
 122
 123         TALLOC_FREE(newkey);
 124         TALLOC_FREE(c_servicename);
 125
 126         return 0;
 127 }
 128
 129 bool share_info_db_init(void)
 130 {
 131         const char *vstring = "INFO/version";
 132         int32 vers_id;
 133         int ret;
 134         bool upgrade_ok = true;
 135
 136         if (share_db != NULL) {
 137                 return True;
 138         }
 139
 140         share_db = db_open(NULL, state_path("share_info.tdb"), 0,
 141                                  TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
 142         if (share_db == NULL) {
 143                 DEBUG(0,("Failed to open share info database %s (%s)\n",
 144                         state_path("share_info.tdb"), strerror(errno) ));
 145                 return False;
 146         }
 147
 148         vers_id = dbwrap_fetch_int32(share_db, vstring);
 149         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 150                 return true;
 151         }
 152
 153         if (share_db->transaction_start(share_db) != 0) {
 154                 DEBUG(0, ("transaction_start failed\n"));
 155                 TALLOC_FREE(share_db);
 156                 return false;
 157         }
 158
 159         vers_id = dbwrap_fetch_int32(share_db, vstring);
 160         if (vers_id == SHARE_DATABASE_VERSION_V3) {
 161                 /*
 162                  * Race condition
 163                  */
 164                 if (share_db->transaction_cancel(share_db)) {
 165                         smb_panic("transaction_cancel failed");
 166                 }
 167                 return true;
 168         }
 169
 170         /* Move to at least V2. */
 171
 172         /* Cope with byte-reversed older versions of the db. */
 173         if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
 174                 /* Written on a bigendian machine with old fetch_int code. Save as le. */
 175
 176                 if (dbwrap_store_int32(share_db, vstring,
 177                                        SHARE_DATABASE_VERSION_V2) != 0) {
 178                         DEBUG(0, ("dbwrap_store_int32 failed\n"));
 179                         goto cancel;
 180                 }
 181                 vers_id = SHARE_DATABASE_VERSION_V2;
 182         }
 183
 184         if (vers_id != SHARE_DATABASE_VERSION_V2) {
 185                 ret = share_db->traverse(share_db, delete_fn, NULL);
 186                 if (ret < 0) {
 187                         DEBUG(0, ("traverse failed\n"));
 188                         goto cancel;
 189                 }
 190                 if (dbwrap_store_int32(share_db, vstring,
 191                                        SHARE_DATABASE_VERSION_V2) != 0) {
 192                         DEBUG(0, ("dbwrap_store_int32 failed\n"));
 193                         goto cancel;
 194                 }
 195         }
 196
 197         /* Finally upgrade to version 3, with canonicalized sharenames. */
 198
 199         ret = share_db->traverse(share_db, upgrade_v2_to_v3, &upgrade_ok);
 200         if (ret < 0 || upgrade_ok == false) {
 201                 DEBUG(0, ("traverse failed\n"));
 202                 goto cancel;
 203         }
 204         if (dbwrap_store_int32(share_db, vstring,
 205                                SHARE_DATABASE_VERSION_V3) != 0) {
 206                 DEBUG(0, ("dbwrap_store_int32 failed\n"));
 207                 goto cancel;
 208         }
 209
 210         if (share_db->transaction_commit(share_db) != 0) {
 211                 DEBUG(0, ("transaction_commit failed\n"));
 212                 return false;
 213         }
 214
 215         return true;
 216
 217  cancel:
 218         if (share_db->transaction_cancel(share_db)) {
 219                 smb_panic("transaction_cancel failed");
 220         }
 221
 222         return false;
 223 }
 224
 225 /*******************************************************************
 226  Fake up a Everyone, default access as a default.
 227  def_access is a GENERIC_XXX access mode.
 228  ********************************************************************/
 229
 230 struct security_descriptor *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32 def_access)
 231 {
 232         uint32_t sa;
 233         struct security_ace ace;
 234         struct security_acl *psa = NULL;
 235         struct security_descriptor *psd = NULL;
 236         uint32 spec_access = def_access;
 237
 238         se_map_generic(&spec_access, &file_generic_mapping);
 239
 240         sa = (def_access | spec_access );
 241         init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);
 242
 243         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
 244                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 245                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 246                                     psa, psize);
 247         }
 248
 249         if (!psd) {
 250                 DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
 251                 return NULL;
 252         }
 253
 254         return psd;
 255 }
 256
 257 /*******************************************************************
 258  Pull a security descriptor from the share tdb.
 259  ********************************************************************/
 260
 261 struct security_descriptor *get_share_security( TALLOC_CTX *ctx, const char *servicename,
 262                               size_t *psize)
 263 {
 264         char *key;
 265         struct security_descriptor *psd = NULL;
 266         TDB_DATA data;
 267         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 268         NTSTATUS status;
 269
 270         if (!c_servicename) {
 271                 return NULL;
 272         }
 273
 274         if (!share_info_db_init()) {
 275                 TALLOC_FREE(c_servicename);
 276                 return NULL;
 277         }
 278
 279         if (!(key = talloc_asprintf(ctx, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_servicename))) {
 280                 TALLOC_FREE(c_servicename);
 281                 DEBUG(0, ("talloc_asprintf failed\n"));
 282                 return NULL;
 283         }
 284
 285         TALLOC_FREE(c_servicename);
 286
 287         data = dbwrap_fetch_bystring(share_db, talloc_tos(), key);
 288
 289         TALLOC_FREE(key);
 290
 291         if (data.dptr == NULL) {
 292                 return get_share_security_default(ctx, psize,
 293                                                   GENERIC_ALL_ACCESS);
 294         }
 295
 296         status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);
 297
 298         TALLOC_FREE(data.dptr);
 299
 300         if (!NT_STATUS_IS_OK(status)) {
 301                 DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
 302                           nt_errstr(status)));
 303                 return get_share_security_default(ctx, psize,
 304                                                   GENERIC_ALL_ACCESS);
 305         }
 306
 307         if (psd) {
 308                 *psize = ndr_size_security_descriptor(psd, 0);
 309         } else {
 310                 return get_share_security_default(ctx, psize,
 311                                                   GENERIC_ALL_ACCESS);
 312         }
 313
 314         return psd;
 315 }
 316
 317 /*******************************************************************
 318  Store a security descriptor in the share db.
 319  ********************************************************************/
 320
 321 bool set_share_security(const char *share_name, struct security_descriptor *psd)
 322 {
 323         TALLOC_CTX *frame = talloc_stackframe();
 324         char *key;
 325         bool ret = False;
 326         TDB_DATA blob;
 327         NTSTATUS status;
 328         char *c_share_name = canonicalize_servicename(frame, share_name);
 329
 330         if (!c_share_name) {
 331                 goto out;
 332         }
 333
 334         if (!share_info_db_init()) {
 335                 goto out;
 336         }
 337
 338         status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);
 339
 340         if (!NT_STATUS_IS_OK(status)) {
 341                 DEBUG(0, ("marshall_sec_desc failed: %s\n",
 342                           nt_errstr(status)));
 343                 goto out;
 344         }
 345
 346         if (!(key = talloc_asprintf(frame, SHARE_SECURITY_DB_KEY_PREFIX_STR "%s", c_share_name))) {
 347                 DEBUG(0, ("talloc_asprintf failed\n"));
 348                 goto out;
 349         }
 350
 351         status = dbwrap_trans_store(share_db, string_term_tdb_data(key), blob,
 352                                     TDB_REPLACE);
 353         if (!NT_STATUS_IS_OK(status)) {
 354                 DEBUG(1, ("set_share_security: Failed to store secdesc for "
 355                           "%s: %s\n", share_name, nt_errstr(status)));
 356                 goto out;
 357         }
 358
 359         DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
 360         ret = True;
 361
 362  out:
 363         TALLOC_FREE(frame);
 364         return ret;
 365 }
 366
 367 /*******************************************************************
 368  Delete a security descriptor.
 369 ********************************************************************/
 370
 371 bool delete_share_security(const char *servicename)
 372 {
 373         TDB_DATA kbuf;
 374         char *key;
 375         NTSTATUS status;
 376         char *c_servicename = canonicalize_servicename(talloc_tos(), servicename);
 377
 378         if (!c_servicename) {
 379                 return NULL;
 380         }
 381
 382         if (!share_info_db_init()) {
 383                 TALLOC_FREE(c_servicename);
 384                 return False;
 385         }
 386
 387         if (!(key = talloc_asprintf(talloc_tos(), SHARE_SECURITY_DB_KEY_PREFIX_STR "%s",
 388                                     c_servicename))) {
 389                 TALLOC_FREE(c_servicename);
 390                 return False;
 391         }
 392         kbuf = string_term_tdb_data(key);
 393
 394         status = dbwrap_trans_delete(share_db, kbuf);
 395         if (!NT_STATUS_IS_OK(status)) {
 396                 DEBUG(0, ("delete_share_security: Failed to delete entry for "
 397                           "share %s: %s\n", c_servicename, nt_errstr(status)));
 398                 TALLOC_FREE(c_servicename);
 399                 return False;
 400         }
 401
 402         TALLOC_FREE(c_servicename);
 403         return True;
 404 }
 405
 406 /*******************************************************************
 407  Can this user access with share with the required permissions ?
 408 ********************************************************************/
 409
 410 bool share_access_check(const struct security_token *token, const char *sharename,
 411                         uint32 desired_access)
 412 {
 413         uint32 granted;
 414         NTSTATUS status;
 415         struct security_descriptor *psd = NULL;
 416         size_t sd_size;
 417
 418         psd = get_share_security(talloc_tos(), sharename, &sd_size);
 419
 420         if (!psd) {
 421                 return True;
 422         }
 423
 424         status = se_access_check(psd, token, desired_access, &granted);
 425
 426         TALLOC_FREE(psd);
 427
 428         return NT_STATUS_IS_OK(status);
 429 }
 430
 431 /***************************************************************************
 432  Parse the contents of an acl string from a usershare file.
 433 ***************************************************************************/
 434
 435 bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, struct security_descriptor **ppsd)
 436 {
 437         size_t s_size = 0;
 438         const char *pacl = acl_str;
 439         int num_aces = 0;
 440         struct security_ace *ace_list = NULL;
 441         struct security_acl *psa = NULL;
 442         struct security_descriptor *psd = NULL;
 443         size_t sd_size = 0;
 444         int i;
 445
 446         *ppsd = NULL;
 447
 448         /* If the acl string is blank return "Everyone:R" */
 449         if (!*acl_str) {
 450                 struct security_descriptor *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
 451                 if (!default_psd) {
 452                         return False;
 453                 }
 454                 *ppsd = default_psd;
 455                 return True;
 456         }
 457
 458         num_aces = 1;
 459
 460         /* Add the number of ',' characters to get the number of aces. */
 461         num_aces += count_chars(pacl,',');
 462
 463         ace_list = TALLOC_ARRAY(ctx, struct security_ace, num_aces);
 464         if (!ace_list) {
 465                 return False;
 466         }
 467
 468         for (i = 0; i < num_aces; i++) {
 469                 uint32_t sa;
 470                 uint32 g_access;
 471                 uint32 s_access;
 472                 struct dom_sid sid;
 473                 char *sidstr;
 474                 enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;
 475
 476                 if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
 477                         DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
 478                                 "for ':' in string '%s'\n", pacl));
 479                         return False;
 480                 }
 481
 482                 if (!string_to_sid(&sid, sidstr)) {
 483                         DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
 484                                 sidstr ));
 485                         return False;
 486                 }
 487
 488                 switch (*pacl) {
 489                         case 'F': /* Full Control, ie. R+W */
 490                         case 'f': /* Full Control, ie. R+W */
 491                                 s_access = g_access = GENERIC_ALL_ACCESS;
 492                                 break;
 493                         case 'R': /* Read only. */
 494                         case 'r': /* Read only. */
 495                                 s_access = g_access = GENERIC_READ_ACCESS;
 496                                 break;
 497                         case 'D': /* Deny all to this SID. */
 498                         case 'd': /* Deny all to this SID. */
 499                                 type = SEC_ACE_TYPE_ACCESS_DENIED;
 500                                 s_access = g_access = GENERIC_ALL_ACCESS;
 501                                 break;
 502                         default:
 503                                 DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
 504                                         pacl ));
 505                                 return False;
 506                 }
 507
 508                 pacl++;
 509                 if (*pacl && *pacl != ',') {
 510                         DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
 511                                 pacl ));
 512                         return False;
 513                 }
 514                 pacl++; /* Go past any ',' */
 515
 516                 se_map_generic(&s_access, &file_generic_mapping);
 517                 sa = (g_access | s_access);
 518                 init_sec_ace(&ace_list[i], &sid, type, sa, 0);
 519         }
 520
 521         if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
 522                 psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
 523                                     SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
 524                                     psa, &sd_size);
 525         }
 526
 527         if (!psd) {
 528                 DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
 529                 return False;
 530         }
 531
 532         *ppsd = psd;
 533         return True;
 534 }