LXR linux/net/ipv4/netfilter/ipt

   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
  20MODULE_LICENSE("GPL");
  21MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
  22MODULE_DESCRIPTION("iptables owner match");
  23
  24static bool
  25match(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
  54static bool
  55checkentry(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
  71static 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
  81static int __init ipt_owner_init(void)
  82{
  83        return xt_register_match(&owner_match);
  84}
  85
  86static void __exit ipt_owner_fini(void)
  87{
  88        xt_unregister_match(&owner_match);
  89}
  90
  91module_init(ipt_owner_init);
  92module_exit(ipt_owner_fini);
  93