Line data    Source code

       1             : /* 
       2             :    Unix SMB/CIFS implementation.
       3             : 
       4             :    check access rules for socket connections
       5             : 
       6             :    Copyright (C) Andrew Tridgell 2004
       7             :    
       8             :    This program is free software; you can redistribute it and/or modify
       9             :    it under the terms of the GNU General Public License as published by
      10             :    the Free Software Foundation; either version 3 of the License, or
      11             :    (at your option) any later version.
      12             :    
      13             :    This program is distributed in the hope that it will be useful,
      14             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
      15             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      16             :    GNU General Public License for more details.
      17             :    
      18             :    You should have received a copy of the GNU General Public License
      19             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.
      20             : */
      21             : 
      22             : 
      23             : /* 
      24             :    This module is an adaption of code from the tcpd-1.4 package written
      25             :    by Wietse Venema, Eindhoven University of Technology, The Netherlands.
      26             : 
      27             :    The code is used here with permission.
      28             : 
      29             :    The code has been considerably changed from the original. Bug reports
      30             :    should be sent to samba-technical@lists.samba.org
      31             : */
      32             : 
      33             : #include "includes.h"
      34             : #include "system/network.h"
      35             : #include "lib/socket/socket.h"
      36             : #include "lib/util/util_net.h"
      37             : #include "lib/util/access.h"
      38             : 
      39             : /* return true if the char* contains ip addrs only.  Used to avoid 
      40             : gethostbyaddr() calls */
      41             : 
      42           0 : static bool only_ipaddrs_in_list(const char** list)
      43             : {
      44           0 :         bool only_ip = true;
      45             :         
      46           0 :         if (!list)
      47           0 :                 return true;
      48             :                         
      49           0 :         for (; *list ; list++) {
      50             :                 /* factor out the special strings */
      51           0 :                 if (strcmp(*list, "ALL")==0 || 
      52           0 :                     strcmp(*list, "FAIL")==0 || 
      53           0 :                     strcmp(*list, "EXCEPT")==0) {
      54           0 :                         continue;
      55             :                 }
      56             :                 
      57           0 :                 if (!is_ipaddress(*list)) {
      58             :                         /* 
      59             :                          * if we failed, make sure that it was not because the token
      60             :                          * was a network/netmask pair.  Only network/netmask pairs
      61             :                          * have a '/' in them
      62             :                          */
      63           0 :                         if ((strchr(*list, '/')) == NULL) {
      64           0 :                                 only_ip = false;
      65           0 :                                 DEBUG(3,("only_ipaddrs_in_list: list has non-ip address (%s)\n", *list));
      66           0 :                                 break;
      67             :                         }
      68             :                 }
      69             :         }
      70             :         
      71           0 :         return only_ip;
      72             : }
      73             : 
      74             : /* return true if access should be allowed to a service for a socket */
      75       96518 : bool socket_check_access(struct socket_context *sock, 
      76             :                          const char *service_name,
      77             :                          const char **allow_list, const char **deny_list)
      78             : {
      79             :         bool ret;
      80       96518 :         const char *name="";
      81             :         struct socket_address *addr;
      82             :         TALLOC_CTX *mem_ctx;
      83             : 
      84       96518 :         if ((!deny_list  || *deny_list==0) && 
      85           0 :             (!allow_list || *allow_list==0)) {
      86       96518 :                 return true;
      87             :         }
      88             : 
      89           0 :         mem_ctx = talloc_init("socket_check_access");
      90           0 :         if (!mem_ctx) {
      91           0 :                 return false;
      92             :         }
      93             : 
      94           0 :         addr = socket_get_peer_addr(sock, mem_ctx);
      95           0 :         if (!addr) {
      96           0 :                 DEBUG(0,("socket_check_access: Denied connection from unknown host: could not get peer address from kernel\n"));
      97           0 :                 talloc_free(mem_ctx);
      98           0 :                 return false;
      99             :         }
     100             : 
     101             :         /* bypass gethostbyaddr() calls if the lists only contain IP addrs */
     102           0 :         if (!only_ipaddrs_in_list(allow_list) || 
     103           0 :             !only_ipaddrs_in_list(deny_list)) {
     104           0 :                 name = socket_get_peer_name(sock, mem_ctx);
     105           0 :                 if (!name) {
     106           0 :                         name = addr->addr;
     107             :                 }
     108             :         }
     109             : 
     110           0 :         if (!addr) {
     111           0 :                 DEBUG(0,("socket_check_access: Denied connection from unknown host\n"));
     112           0 :                 talloc_free(mem_ctx);
     113           0 :                 return false;
     114             :         }
     115             : 
     116           0 :         ret = allow_access(deny_list, allow_list, name, addr->addr);
     117             :         
     118           0 :         if (ret) {
     119           0 :                 DEBUG(2,("socket_check_access: Allowed connection to '%s' from %s (%s)\n", 
     120             :                          service_name, name, addr->addr));
     121             :         } else {
     122           0 :                 DEBUG(0,("socket_check_access: Denied connection to '%s' from %s (%s)\n", 
     123             :                          service_name, name, addr->addr));
     124             :         }
     125             : 
     126           0 :         talloc_free(mem_ctx);
     127             : 
     128           0 :         return ret;
     129             : }