net/ipv4/netfilter/ipt_owner.c

   1 /* Kernel module to match various things tied to sockets associated with
   2    locally generated outgoing packets. */
   3
   4 /* (C) 2000 Marc Boucher <marc@mbsi.ca>
   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 version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/skbuff.h>
  13 #include <linux/file.h>
  14 #include <linux/rcupdate.h>
  15 #include <net/sock.h>
  16
  17 #include <linux/netfilter_ipv4/ipt_owner.h>
  18 #include <linux/netfilter/x_tables.h>
  19
  20 MODULE_LICENSE("GPL");
  21 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
  22 MODULE_DESCRIPTION("iptables owner match");
  23
  24 static bool
  25 match(const struct sk_buff *skb,
  26       const struct net_device *in,
  27       const struct net_device *out,
  28       const struct xt_match *match,
  29       const void *matchinfo,
  30       int offset,
  31       unsigned int protoff,
  32       bool *hotdrop)
  33 {
  34         const struct ipt_owner_info *info = matchinfo;
  35
  36         if (!skb->sk || !skb->sk->sk_socket || !skb->sk->sk_socket->file)
  37                 return false;
  38
  39         if(info->match & IPT_OWNER_UID) {
  40                 if ((skb->sk->sk_socket->file->f_uid != info->uid) ^
  41                     !!(info->invert & IPT_OWNER_UID))
  42                         return false;
  43         }
  44
  45         if(info->match & IPT_OWNER_GID) {
  46                 if ((skb->sk->sk_socket->file->f_gid != info->gid) ^
  47                     !!(info->invert & IPT_OWNER_GID))
  48                         return false;
  49         }
  50
  51         return true;
  52 }
  53
  54 static bool
  55 checkentry(const char *tablename,
  56            const void *ip,
  57            const struct xt_match *match,
  58            void *matchinfo,
  59            unsigned int hook_mask)
  60 {
  61         const struct ipt_owner_info *info = matchinfo;
  62
  63         if (info->match & (IPT_OWNER_PID|IPT_OWNER_SID|IPT_OWNER_COMM)) {
  64                 printk("ipt_owner: pid, sid and command matching "
  65                        "not supported anymore\n");
  66                 return false;
  67         }
  68         return true;
  69 }
  70
  71 static struct xt_match owner_match __read_mostly = {
  72         .name           = "owner",
  73         .family         = AF_INET,
  74         .match          = match,
  75         .matchsize      = sizeof(struct ipt_owner_info),
  76         .hooks          = (1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_POST_ROUTING),
  77         .checkentry     = checkentry,
  78         .me             = THIS_MODULE,
  79 };
  80
  81 static int __init ipt_owner_init(void)
  82 {
  83         return xt_register_match(&owner_match);
  84 }
  85
  86 static void __exit ipt_owner_fini(void)
  87 {
  88         xt_unregister_match(&owner_match);
  89 }
  90
  91 module_init(ipt_owner_init);
  92 module_exit(ipt_owner_fini);