[mirror_ubuntu-jammy-kernel.git] / net / ipv4 / netfilter / ipt_REJECT.c

/*
 * This is a module which is used for rejecting packets.
 */

/* (C) 1999-2001 Paul `Rusty' Russell
 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
 *
 * 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.
 */
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/slab.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <net/icmp.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter_ipv4/ipt_REJECT.h>
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
#include <linux/netfilter_bridge.h>
#endif

#include <net/netfilter/ipv4/nf_reject.h>

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv4");

static unsigned int
reject_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
	const struct ipt_reject_info *reject = par->targinfo;

	switch (reject->with) {
	case IPT_ICMP_NET_UNREACHABLE:
		nf_send_unreach(skb, ICMP_NET_UNREACH);
		break;
	case IPT_ICMP_HOST_UNREACHABLE:
		nf_send_unreach(skb, ICMP_HOST_UNREACH);
		break;
	case IPT_ICMP_PROT_UNREACHABLE:
		nf_send_unreach(skb, ICMP_PROT_UNREACH);
		break;
	case IPT_ICMP_PORT_UNREACHABLE:
		nf_send_unreach(skb, ICMP_PORT_UNREACH);
		break;
	case IPT_ICMP_NET_PROHIBITED:
		nf_send_unreach(skb, ICMP_NET_ANO);
		break;
	case IPT_ICMP_HOST_PROHIBITED:
		nf_send_unreach(skb, ICMP_HOST_ANO);
		break;
	case IPT_ICMP_ADMIN_PROHIBITED:
		nf_send_unreach(skb, ICMP_PKT_FILTERED);
		break;
	case IPT_TCP_RESET:
		nf_send_reset(skb, par->hooknum);
	case IPT_ICMP_ECHOREPLY:
		/* Doesn't happen. */
		break;
	}

	return NF_DROP;
}

static int reject_tg_check(const struct xt_tgchk_param *par)
{
	const struct ipt_reject_info *rejinfo = par->targinfo;
	const struct ipt_entry *e = par->entryinfo;

	if (rejinfo->with == IPT_ICMP_ECHOREPLY) {
		pr_info("ECHOREPLY no longer supported.\n");
		return -EINVAL;
	} else if (rejinfo->with == IPT_TCP_RESET) {
		/* Must specify that it's a TCP packet */
		if (e->ip.proto != IPPROTO_TCP ||
		    (e->ip.invflags & XT_INV_PROTO)) {
			pr_info("TCP_RESET invalid for non-tcp\n");
			return -EINVAL;
		}
	}
	return 0;
}

static struct xt_target reject_tg_reg __read_mostly = {
	.name		= "REJECT",
	.family		= NFPROTO_IPV4,
	.target		= reject_tg,
	.targetsize	= sizeof(struct ipt_reject_info),
	.table		= "filter",
	.hooks		= (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
			  (1 << NF_INET_LOCAL_OUT),
	.checkentry	= reject_tg_check,
	.me		= THIS_MODULE,
};

static int __init reject_tg_init(void)
{
	return xt_register_target(&reject_tg_reg);
}

static void __exit reject_tg_exit(void)
{
	xt_unregister_target(&reject_tg_reg);
}

module_init(reject_tg_init);
module_exit(reject_tg_exit);
Commit	Line	Data
1da177e4 LT	1	/*
1da177e4 LT	2	* This is a module which is used for rejecting packets.
1da177e4 LT	3	*/
	4
	5	/* (C) 1999-2001 Paul `Rusty' Russell
	6	* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
ff67e4e4	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
1da177e4 LT	13	#include <linux/module.h>
1da177e4 LT	14	#include <linux/skbuff.h>
5a0e3ad6	15	#include <linux/slab.h>
1da177e4 LT	16	#include <linux/ip.h>
	17	#include <linux/udp.h>
	18	#include <linux/icmp.h>
	19	#include <net/icmp.h>
6709dbbb	20	#include <linux/netfilter/x_tables.h>
1da177e4 LT	21	#include <linux/netfilter_ipv4/ip_tables.h>
1da177e4 LT	22	#include <linux/netfilter_ipv4/ipt_REJECT.h>
1109a90c	23	#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
1da177e4 LT	24	#include <linux/netfilter_bridge.h>
	25	#endif
	26
cc70d069 EL	27	#include <net/netfilter/ipv4/nf_reject.h>
cc70d069 EL	28
1da177e4 LT	29	MODULE_LICENSE("GPL");
1da177e4 LT	30	MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
2ae15b64	31	MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv4");
1da177e4	32
d3c5ee6d	33	static unsigned int
4b560b44	34	reject_tg(struct sk_buff skb, const struct xt_action_param par)
1da177e4	35	{
7eb35586	36	const struct ipt_reject_info *reject = par->targinfo;
1da177e4	37
e905a9ed YH	38	switch (reject->with) {
e905a9ed YH	39	case IPT_ICMP_NET_UNREACHABLE:
cc70d069	40	nf_send_unreach(skb, ICMP_NET_UNREACH);
e905a9ed YH	41	break;
e905a9ed YH	42	case IPT_ICMP_HOST_UNREACHABLE:
cc70d069	43	nf_send_unreach(skb, ICMP_HOST_UNREACH);
e905a9ed YH	44	break;
e905a9ed YH	45	case IPT_ICMP_PROT_UNREACHABLE:
cc70d069	46	nf_send_unreach(skb, ICMP_PROT_UNREACH);
e905a9ed YH	47	break;
e905a9ed YH	48	case IPT_ICMP_PORT_UNREACHABLE:
cc70d069	49	nf_send_unreach(skb, ICMP_PORT_UNREACH);
e905a9ed YH	50	break;
e905a9ed YH	51	case IPT_ICMP_NET_PROHIBITED:
cc70d069	52	nf_send_unreach(skb, ICMP_NET_ANO);
e905a9ed	53	break;
1da177e4	54	case IPT_ICMP_HOST_PROHIBITED:
cc70d069	55	nf_send_unreach(skb, ICMP_HOST_ANO);
e905a9ed YH	56	break;
e905a9ed YH	57	case IPT_ICMP_ADMIN_PROHIBITED:
cc70d069	58	nf_send_unreach(skb, ICMP_PKT_FILTERED);
1da177e4 LT	59	break;
1da177e4 LT	60	case IPT_TCP_RESET:
cc70d069	61	nf_send_reset(skb, par->hooknum);
1da177e4 LT	62	case IPT_ICMP_ECHOREPLY:
	63	/* Doesn't happen. */
	64	break;
	65	}
	66
	67	return NF_DROP;
	68	}
	69
135367b8	70	static int reject_tg_check(const struct xt_tgchk_param *par)
1da177e4	71	{
af5d6dc2 JE	72	const struct ipt_reject_info *rejinfo = par->targinfo;
af5d6dc2 JE	73	const struct ipt_entry *e = par->entryinfo;
1da177e4	74
1da177e4	75	if (rejinfo->with == IPT_ICMP_ECHOREPLY) {
ff67e4e4	76	pr_info("ECHOREPLY no longer supported.\n");
d6b00a53	77	return -EINVAL;
1da177e4 LT	78	} else if (rejinfo->with == IPT_TCP_RESET) {
1da177e4 LT	79	/* Must specify that it's a TCP packet */
3666ed1c JP	80	if (e->ip.proto != IPPROTO_TCP \|\|
3666ed1c JP	81	(e->ip.invflags & XT_INV_PROTO)) {
ff67e4e4	82	pr_info("TCP_RESET invalid for non-tcp\n");
d6b00a53	83	return -EINVAL;
1da177e4 LT	84	}
1da177e4 LT	85	}
d6b00a53	86	return 0;
1da177e4 LT	87	}
1da177e4 LT	88
d3c5ee6d	89	static struct xt_target reject_tg_reg __read_mostly = {
1da177e4	90	.name = "REJECT",
ee999d8b	91	.family = NFPROTO_IPV4,
d3c5ee6d	92	.target = reject_tg,
1d5cd909 PM	93	.targetsize = sizeof(struct ipt_reject_info),
1d5cd909 PM	94	.table = "filter",
6e23ae2a PM	95	.hooks = (1 << NF_INET_LOCAL_IN) \| (1 << NF_INET_FORWARD) \|
6e23ae2a PM	96	(1 << NF_INET_LOCAL_OUT),
d3c5ee6d	97	.checkentry = reject_tg_check,
1da177e4 LT	98	.me = THIS_MODULE,
	99	};
	100
d3c5ee6d	101	static int __init reject_tg_init(void)
1da177e4	102	{
d3c5ee6d	103	return xt_register_target(&reject_tg_reg);
1da177e4 LT	104	}
1da177e4 LT	105
d3c5ee6d	106	static void __exit reject_tg_exit(void)
1da177e4	107	{
d3c5ee6d	108	xt_unregister_target(&reject_tg_reg);
1da177e4 LT	109	}
1da177e4 LT	110
d3c5ee6d JE	111	module_init(reject_tg_init);
d3c5ee6d JE	112	module_exit(reject_tg_exit);