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