Logo Search packages:      
Sourcecode: likewise-open version File versions  Download package

sharesec.c

/* 
 *  Unix SMB/Netbios implementation.
 *  SEC_DESC handling functions
 *  Copyright (C) Jeremy R. Allison            1995-2003.
 *  
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 3 of the License, or
 *  (at your option) any later version.
 *  
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *  
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 */

#include "includes.h"

/*******************************************************************
 Create the share security tdb.
 ********************************************************************/

static TDB_CONTEXT *share_tdb; /* used for share security descriptors */
#define SHARE_DATABASE_VERSION_V1 1
#define SHARE_DATABASE_VERSION_V2 2 /* version id in little endian. */

/* Map generic permissions to file object specific permissions */

static const struct generic_mapping file_generic_mapping = {
        FILE_GENERIC_READ,
        FILE_GENERIC_WRITE,
        FILE_GENERIC_EXECUTE,
        FILE_GENERIC_ALL
};


static bool share_info_db_init(void)
{
      const char *vstring = "INFO/version";
      int32 vers_id;
 
      if (share_tdb) {
            return True;
      }

      share_tdb = tdb_open_log(state_path("share_info.tdb"), 0, TDB_DEFAULT, O_RDWR|O_CREAT, 0600);
      if (!share_tdb) {
            DEBUG(0,("Failed to open share info database %s (%s)\n",
                  state_path("share_info.tdb"), strerror(errno) ));
            return False;
      }
 
      /* handle a Samba upgrade */
      tdb_lock_bystring(share_tdb, vstring);

      /* Cope with byte-reversed older versions of the db. */
      vers_id = tdb_fetch_int32(share_tdb, vstring);
      if ((vers_id == SHARE_DATABASE_VERSION_V1) || (IREV(vers_id) == SHARE_DATABASE_VERSION_V1)) {
            /* Written on a bigendian machine with old fetch_int code. Save as le. */
            tdb_store_int32(share_tdb, vstring, SHARE_DATABASE_VERSION_V2);
            vers_id = SHARE_DATABASE_VERSION_V2;
      }

      if (vers_id != SHARE_DATABASE_VERSION_V2) {
            tdb_traverse(share_tdb, tdb_traverse_delete_fn, NULL);
            tdb_store_int32(share_tdb, vstring, SHARE_DATABASE_VERSION_V2);
      }
      tdb_unlock_bystring(share_tdb, vstring);

      return True;
}

/*******************************************************************
 Fake up a Everyone, default access as a default.
 def_access is a GENERIC_XXX access mode.
 ********************************************************************/

SEC_DESC *get_share_security_default( TALLOC_CTX *ctx, size_t *psize, uint32 def_access)
{
      SEC_ACCESS sa;
      SEC_ACE ace;
      SEC_ACL *psa = NULL;
      SEC_DESC *psd = NULL;
      uint32 spec_access = def_access;

      se_map_generic(&spec_access, &file_generic_mapping);

      init_sec_access(&sa, def_access | spec_access );
      init_sec_ace(&ace, &global_sid_World, SEC_ACE_TYPE_ACCESS_ALLOWED, sa, 0);

      if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, 1, &ace)) != NULL) {
            psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
                            SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
                            psa, psize);
      }

      if (!psd) {
            DEBUG(0,("get_share_security: Failed to make SEC_DESC.\n"));
            return NULL;
      }

      return psd;
}

/*******************************************************************
 Pull a security descriptor from the share tdb.
 ********************************************************************/

SEC_DESC *get_share_security( TALLOC_CTX *ctx, const char *servicename,
                        size_t *psize)
{
      char *key;
      SEC_DESC *psd = NULL;
      TDB_DATA data;
      NTSTATUS status;

      if (!share_info_db_init()) {
            return NULL;
      }

      if (!(key = talloc_asprintf(ctx, "SECDESC/%s", servicename))) {
            DEBUG(0, ("talloc_asprintf failed\n"));
            return NULL;
      }

      data = tdb_fetch_bystring(share_tdb, key);

      TALLOC_FREE(key);

      if (data.dptr == NULL) {
            return get_share_security_default(ctx, psize,
                                      GENERIC_ALL_ACCESS);
      }

      status = unmarshall_sec_desc(ctx, data.dptr, data.dsize, &psd);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("unmarshall_sec_desc failed: %s\n",
                    nt_errstr(status)));
            return NULL;
      }

      if (psd)
            *psize = ndr_size_security_descriptor(psd, 0);

      return psd;
}

/*******************************************************************
 Store a security descriptor in the share db.
 ********************************************************************/

bool set_share_security(const char *share_name, SEC_DESC *psd)
{
      TALLOC_CTX *frame;
      char *key;
      bool ret = False;
      TDB_DATA blob;
      NTSTATUS status;

      if (!share_info_db_init()) {
            return False;
      }

      frame = talloc_stackframe();

      status = marshall_sec_desc(frame, psd, &blob.dptr, &blob.dsize);

      if (!NT_STATUS_IS_OK(status)) {
            DEBUG(0, ("marshall_sec_desc failed: %s\n",
                    nt_errstr(status)));
            goto out;
      }

      if (!(key = talloc_asprintf(frame, "SECDESC/%s", share_name))) {
            DEBUG(0, ("talloc_asprintf failed\n"));
            goto out;
      }

      if (tdb_trans_store_bystring(share_tdb, key, blob,
                             TDB_REPLACE) == -1) {
            DEBUG(1,("set_share_security: Failed to store secdesc for "
                   "%s\n", share_name ));
            goto out;
      }

      DEBUG(5,("set_share_security: stored secdesc for %s\n", share_name ));
      ret = True;

 out:
      TALLOC_FREE(frame);
      return ret;
}

/*******************************************************************
 Delete a security descriptor.
********************************************************************/

bool delete_share_security(const char *servicename)
{
      TDB_DATA kbuf;
      char *key;

      if (!(key = talloc_asprintf(talloc_tos(), "SECDESC/%s",
                            servicename))) {
            return False;
      }
      kbuf = string_term_tdb_data(key);

      if (tdb_trans_delete(share_tdb, kbuf) != 0) {
            DEBUG(0, ("delete_share_security: Failed to delete entry for "
                    "share %s\n", servicename));
            return False;
      }

      return True;
}

/*******************************************************************
 Can this user access with share with the required permissions ?
********************************************************************/

bool share_access_check(const NT_USER_TOKEN *token, const char *sharename,
                  uint32 desired_access)
{
      uint32 granted;
      NTSTATUS status;
      SEC_DESC *psd = NULL;
      size_t sd_size;
      bool ret = True;

      psd = get_share_security(talloc_tos(), sharename, &sd_size);

      if (!psd) {
            return True;
      }

      ret = se_access_check(psd, token, desired_access, &granted, &status);

      TALLOC_FREE(psd);

      return ret;
}

/***************************************************************************
 Parse the contents of an acl string from a usershare file.
***************************************************************************/

bool parse_usershare_acl(TALLOC_CTX *ctx, const char *acl_str, SEC_DESC **ppsd)
{
      size_t s_size = 0;
      const char *pacl = acl_str;
      int num_aces = 0;
      SEC_ACE *ace_list = NULL;
      SEC_ACL *psa = NULL;
      SEC_DESC *psd = NULL;
      size_t sd_size = 0;
      int i;

      *ppsd = NULL;

      /* If the acl string is blank return "Everyone:R" */
      if (!*acl_str) {
            SEC_DESC *default_psd = get_share_security_default(ctx, &s_size, GENERIC_READ_ACCESS);
            if (!default_psd) {
                  return False;
            }
            *ppsd = default_psd;
            return True;
      }

      num_aces = 1;

      /* Add the number of ',' characters to get the number of aces. */
      num_aces += count_chars(pacl,',');

      ace_list = TALLOC_ARRAY(ctx, SEC_ACE, num_aces);
      if (!ace_list) {
            return False;
      }

      for (i = 0; i < num_aces; i++) {
            SEC_ACCESS sa;
            uint32 g_access;
            uint32 s_access;
            DOM_SID sid;
            char *sidstr;
            enum security_ace_type type = SEC_ACE_TYPE_ACCESS_ALLOWED;

            if (!next_token_talloc(ctx, &pacl, &sidstr, ":")) {
                  DEBUG(0,("parse_usershare_acl: malformed usershare acl looking "
                        "for ':' in string '%s'\n", pacl));
                  return False;
            }

            if (!string_to_sid(&sid, sidstr)) {
                  DEBUG(0,("parse_usershare_acl: failed to convert %s to sid.\n",
                        sidstr ));
                  return False;
            }

            switch (*pacl) {
                  case 'F': /* Full Control, ie. R+W */
                  case 'f': /* Full Control, ie. R+W */
                        s_access = g_access = GENERIC_ALL_ACCESS;
                        break;
                  case 'R': /* Read only. */
                  case 'r': /* Read only. */
                        s_access = g_access = GENERIC_READ_ACCESS;
                        break;
                  case 'D': /* Deny all to this SID. */
                  case 'd': /* Deny all to this SID. */
                        type = SEC_ACE_TYPE_ACCESS_DENIED;
                        s_access = g_access = GENERIC_ALL_ACCESS;
                        break;
                  default:
                        DEBUG(0,("parse_usershare_acl: unknown acl type at %s.\n",
                              pacl ));
                        return False;
            }

            pacl++;
            if (*pacl && *pacl != ',') {
                  DEBUG(0,("parse_usershare_acl: bad acl string at %s.\n",
                        pacl ));
                  return False;
            }
            pacl++; /* Go past any ',' */

            se_map_generic(&s_access, &file_generic_mapping);
            init_sec_access(&sa, g_access | s_access );
            init_sec_ace(&ace_list[i], &sid, type, sa, 0);
      }

      if ((psa = make_sec_acl(ctx, NT4_ACL_REVISION, num_aces, ace_list)) != NULL) {
            psd = make_sec_desc(ctx, SECURITY_DESCRIPTOR_REVISION_1,
                            SEC_DESC_SELF_RELATIVE, NULL, NULL, NULL,
                            psa, &sd_size);
      }

      if (!psd) {
            DEBUG(0,("parse_usershare_acl: Failed to make SEC_DESC.\n"));
            return False;
      }

      *ppsd = psd;
      return True;
}

Generated by  Doxygen 1.6.0   Back to index