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