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_ipv4/ip_tables.h>
  19
  20 MODULE_LICENSE("GPL");
  21 MODULE_AUTHOR("Marc Boucher <marc@mbsi.ca>");
  22 MODULE_DESCRIPTION("iptables owner match");
  23
  24 static int
  25 match(const struct sk_buff *skb,
  26       const struct net_device *in,
  27       const struct net_device *out,
  28       const void *matchinfo,
  29       int offset,
  30       int *hotdrop)
  31 {
  32         const struct ipt_owner_info *info = matchinfo;
  33
  34         if (!skb->sk || !skb->sk->sk_socket || !skb->sk->sk_socket->file)
  35                 return 0;
  36
  37         if(info->match & IPT_OWNER_UID) {
  38                 if ((skb->sk->sk_socket->file->f_uid != info->uid) ^
  39                     !!(info->invert & IPT_OWNER_UID))
  40                         return 0;
  41         }
  42
  43         if(info->match & IPT_OWNER_GID) {
  44                 if ((skb->sk->sk_socket->file->f_gid != info->gid) ^
  45                     !!(info->invert & IPT_OWNER_GID))
  46                         return 0;
  47         }
  48
  49         return 1;
  50 }
  51
  52 static int
  53 checkentry(const char *tablename,
  54            const struct ipt_ip *ip,
  55            void *matchinfo,
  56            unsigned int matchsize,
  57            unsigned int hook_mask)
  58 {
  59         const struct ipt_owner_info *info = matchinfo;
  60
  61         if (hook_mask
  62             & ~((1 << NF_IP_LOCAL_OUT) | (1 << NF_IP_POST_ROUTING))) {
  63                 printk("ipt_owner: only valid for LOCAL_OUT or POST_ROUTING.\n");
  64                 return 0;
  65         }
  66
  67         if (matchsize != IPT_ALIGN(sizeof(struct ipt_owner_info))) {
  68                 printk("Matchsize %u != %Zu\n", matchsize,
  69                        IPT_ALIGN(sizeof(struct ipt_owner_info)));
  70                 return 0;
  71         }
  72
  73         if (info->match & (IPT_OWNER_PID|IPT_OWNER_SID|IPT_OWNER_COMM)) {
  74                 printk("ipt_owner: pid, sid and command matching "
  75                        "not supported anymore\n");
  76                 return 0;
  77         }
  78
  79         return 1;
  80 }
  81
  82 static struct ipt_match owner_match = {
  83         .name           = "owner",
  84         .match          = &match,
  85         .checkentry     = &checkentry,
  86         .me             = THIS_MODULE,
  87 };
  88
  89 static int __init init(void)
  90 {
  91         return ipt_register_match(&owner_match);
  92 }
  93
  94 static void __exit fini(void)
  95 {
  96         ipt_unregister_match(&owner_match);
  97 }
  98
  99 module_init(init);
 100 module_exit(fini);