root/net/netfilter/xt_owner.c

DEFINITIONS

1. owner_mt_v0
2. owner_mt6_v0
3. owner_mt
4. owner_mt_check_v0
5. owner_mt6_check_v0
6. owner_mt_init
7. owner_mt_exit

/*
 * Kernel module to match various things tied to sockets associated with
 * locally generated outgoing packets.
 *
 * (C) 2000 Marc Boucher <marc@mbsi.ca>
 *
 * Copyright © CC Computer Consultants GmbH, 2007 - 2008
 * <jengelh@computergmbh.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/file.h>
#include <net/sock.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_owner.h>
#include <linux/netfilter_ipv4/ipt_owner.h>
#include <linux/netfilter_ipv6/ip6t_owner.h>

static bool
owner_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct ipt_owner_info *info = par->matchinfo;
        const struct file *filp;

        if (skb->sk == NULL || skb->sk->sk_socket == NULL)
                return false;

        filp = skb->sk->sk_socket->file;
        if (filp == NULL)
                return false;

        if (info->match & IPT_OWNER_UID)
                if ((filp->f_uid != info->uid) ^
                    !!(info->invert & IPT_OWNER_UID))
                        return false;

        if (info->match & IPT_OWNER_GID)
                if ((filp->f_gid != info->gid) ^
                    !!(info->invert & IPT_OWNER_GID))
                        return false;

        return true;
}

static bool
owner_mt6_v0(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct ip6t_owner_info *info = par->matchinfo;
        const struct file *filp;

        if (skb->sk == NULL || skb->sk->sk_socket == NULL)
                return false;

        filp = skb->sk->sk_socket->file;
        if (filp == NULL)
                return false;

        if (info->match & IP6T_OWNER_UID)
                if ((filp->f_uid != info->uid) ^
                    !!(info->invert & IP6T_OWNER_UID))
                        return false;

        if (info->match & IP6T_OWNER_GID)
                if ((filp->f_gid != info->gid) ^
                    !!(info->invert & IP6T_OWNER_GID))
                        return false;

        return true;
}

static bool
owner_mt(const struct sk_buff *skb, const struct xt_match_param *par)
{
        const struct xt_owner_match_info *info = par->matchinfo;
        const struct file *filp;

        if (skb->sk == NULL || skb->sk->sk_socket == NULL)
                return (info->match ^ info->invert) == 0;
        else if (info->match & info->invert & XT_OWNER_SOCKET)
                /*
                 * Socket exists but user wanted ! --socket-exists.
                 * (Single ampersands intended.)
                 */
                return false;

        filp = skb->sk->sk_socket->file;
        if (filp == NULL)
                return ((info->match ^ info->invert) &
                       (XT_OWNER_UID | XT_OWNER_GID)) == 0;

        if (info->match & XT_OWNER_UID)
                if ((filp->f_uid >= info->uid_min &&
                    filp->f_uid <= info->uid_max) ^
                    !(info->invert & XT_OWNER_UID))
                        return false;

        if (info->match & XT_OWNER_GID)
                if ((filp->f_gid >= info->gid_min &&
                    filp->f_gid <= info->gid_max) ^
                    !(info->invert & XT_OWNER_GID))
                        return false;

        return true;
}

static bool owner_mt_check_v0(const struct xt_mtchk_param *par)
{
        const struct ipt_owner_info *info = par->matchinfo;

        if (info->match & (IPT_OWNER_PID | IPT_OWNER_SID | IPT_OWNER_COMM)) {
                printk(KERN_WARNING KBUILD_MODNAME
                       ": PID, SID and command matching is not "
                       "supported anymore\n");
                return false;
        }

        return true;
}

static bool owner_mt6_check_v0(const struct xt_mtchk_param *par)
{
        const struct ip6t_owner_info *info = par->matchinfo;

        if (info->match & (IP6T_OWNER_PID | IP6T_OWNER_SID)) {
                printk(KERN_WARNING KBUILD_MODNAME
                       ": PID and SID matching is not supported anymore\n");
                return false;
        }

        return true;
}

static struct xt_match owner_mt_reg[] __read_mostly = {
        {
                .name       = "owner",
                .revision   = 0,
                .family     = NFPROTO_IPV4,
                .match      = owner_mt_v0,
                .matchsize  = sizeof(struct ipt_owner_info),
                .checkentry = owner_mt_check_v0,
                .hooks      = (1 << NF_INET_LOCAL_OUT) |
                              (1 << NF_INET_POST_ROUTING),
                .me         = THIS_MODULE,
        },
        {
                .name       = "owner",
                .revision   = 0,
                .family     = NFPROTO_IPV6,
                .match      = owner_mt6_v0,
                .matchsize  = sizeof(struct ip6t_owner_info),
                .checkentry = owner_mt6_check_v0,
                .hooks      = (1 << NF_INET_LOCAL_OUT) |
                              (1 << NF_INET_POST_ROUTING),
                .me         = THIS_MODULE,
        },
        {
                .name       = "owner",
                .revision   = 1,
                .family     = NFPROTO_UNSPEC,
                .match      = owner_mt,
                .matchsize  = sizeof(struct xt_owner_match_info),
                .hooks      = (1 << NF_INET_LOCAL_OUT) |
                              (1 << NF_INET_POST_ROUTING),
                .me         = THIS_MODULE,
        },
};

static int __init owner_mt_init(void)
{
        return xt_register_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
}

static void __exit owner_mt_exit(void)
{
        xt_unregister_matches(owner_mt_reg, ARRAY_SIZE(owner_mt_reg));
}

module_init(owner_mt_init);
module_exit(owner_mt_exit);
MODULE_AUTHOR("Jan Engelhardt <jengelh@computergmbh.de>");
MODULE_DESCRIPTION("Xtables: socket owner matching");
MODULE_LICENSE("GPL");
MODULE_ALIAS("ipt_owner");
MODULE_ALIAS("ip6t_owner");