net/netfilter/xt_cgroup.c

   1 /*
   2  * Xtables module to match the process control group.
   3  *
   4  * Might be used to implement individual "per-application" firewall
   5  * policies in contrast to global policies based on control groups.
   6  * Matching is based upon processes tagged to net_cls' classid marker.
   7  *
   8  * (C) 2013 Daniel Borkmann <dborkman@redhat.com>
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License version 2 as
  12  * published by the Free Software Foundation.
  13  */
  14
  15 #include <linux/skbuff.h>
  16 #include <linux/module.h>
  17 #include <linux/netfilter/x_tables.h>
  18 #include <linux/netfilter/xt_cgroup.h>
  19 #include <net/sock.h>
  20
  21 MODULE_LICENSE("GPL");
  22 MODULE_AUTHOR("Daniel Borkmann <dborkman@redhat.com>");
  23 MODULE_DESCRIPTION("Xtables: process control group matching");
  24 MODULE_ALIAS("ipt_cgroup");
  25 MODULE_ALIAS("ip6t_cgroup");
  26
  27 static int cgroup_mt_check(const struct xt_mtchk_param *par)
  28 {
  29         struct xt_cgroup_info *info = par->matchinfo;
  30
  31         if (info->invert & ~1)
  32                 return -EINVAL;
  33
  34         return info->id ? 0 : -EINVAL;
  35 }
  36
  37 static bool
  38 cgroup_mt(const struct sk_buff *skb, struct xt_action_param *par)
  39 {
  40         const struct xt_cgroup_info *info = par->matchinfo;
  41
  42         if (skb->sk == NULL)
  43                 return false;
  44
  45         return (info->id == skb->sk->sk_classid) ^ info->invert;
  46 }
  47
  48 static struct xt_match cgroup_mt_reg __read_mostly = {
  49         .name       = "cgroup",
  50         .revision   = 0,
  51         .family     = NFPROTO_UNSPEC,
  52         .checkentry = cgroup_mt_check,
  53         .match      = cgroup_mt,
  54         .matchsize  = sizeof(struct xt_cgroup_info),
  55         .me         = THIS_MODULE,
  56         .hooks      = (1 << NF_INET_LOCAL_OUT) |
  57                       (1 << NF_INET_POST_ROUTING) |
  58                       (1 << NF_INET_LOCAL_IN),
  59 };
  60
  61 static int __init cgroup_mt_init(void)
  62 {
  63         return xt_register_match(&cgroup_mt_reg);
  64 }
  65
  66 static void __exit cgroup_mt_exit(void)
  67 {
  68         xt_unregister_match(&cgroup_mt_reg);
  69 }
  70
  71 module_init(cgroup_mt_init);
  72 module_exit(cgroup_mt_exit);