cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ipt_REJECT.c (2947B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * This is a module which is used for rejecting packets.
      4 */
      5
      6/* (C) 1999-2001 Paul `Rusty' Russell
      7 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
      8 */
      9#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
     10#include <linux/module.h>
     11#include <linux/skbuff.h>
     12#include <linux/slab.h>
     13#include <linux/ip.h>
     14#include <linux/udp.h>
     15#include <linux/icmp.h>
     16#include <net/icmp.h>
     17#include <linux/netfilter/x_tables.h>
     18#include <linux/netfilter_ipv4/ip_tables.h>
     19#include <linux/netfilter_ipv4/ipt_REJECT.h>
     20#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
     21#include <linux/netfilter_bridge.h>
     22#endif
     23
     24#include <net/netfilter/ipv4/nf_reject.h>
     25
     26MODULE_LICENSE("GPL");
     27MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
     28MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv4");
     29
     30static unsigned int
     31reject_tg(struct sk_buff *skb, const struct xt_action_param *par)
     32{
     33	const struct ipt_reject_info *reject = par->targinfo;
     34	int hook = xt_hooknum(par);
     35
     36	switch (reject->with) {
     37	case IPT_ICMP_NET_UNREACHABLE:
     38		nf_send_unreach(skb, ICMP_NET_UNREACH, hook);
     39		break;
     40	case IPT_ICMP_HOST_UNREACHABLE:
     41		nf_send_unreach(skb, ICMP_HOST_UNREACH, hook);
     42		break;
     43	case IPT_ICMP_PROT_UNREACHABLE:
     44		nf_send_unreach(skb, ICMP_PROT_UNREACH, hook);
     45		break;
     46	case IPT_ICMP_PORT_UNREACHABLE:
     47		nf_send_unreach(skb, ICMP_PORT_UNREACH, hook);
     48		break;
     49	case IPT_ICMP_NET_PROHIBITED:
     50		nf_send_unreach(skb, ICMP_NET_ANO, hook);
     51		break;
     52	case IPT_ICMP_HOST_PROHIBITED:
     53		nf_send_unreach(skb, ICMP_HOST_ANO, hook);
     54		break;
     55	case IPT_ICMP_ADMIN_PROHIBITED:
     56		nf_send_unreach(skb, ICMP_PKT_FILTERED, hook);
     57		break;
     58	case IPT_TCP_RESET:
     59		nf_send_reset(xt_net(par), par->state->sk, skb, hook);
     60		break;
     61	case IPT_ICMP_ECHOREPLY:
     62		/* Doesn't happen. */
     63		break;
     64	}
     65
     66	return NF_DROP;
     67}
     68
     69static int reject_tg_check(const struct xt_tgchk_param *par)
     70{
     71	const struct ipt_reject_info *rejinfo = par->targinfo;
     72	const struct ipt_entry *e = par->entryinfo;
     73
     74	if (rejinfo->with == IPT_ICMP_ECHOREPLY) {
     75		pr_info_ratelimited("ECHOREPLY no longer supported.\n");
     76		return -EINVAL;
     77	} else if (rejinfo->with == IPT_TCP_RESET) {
     78		/* Must specify that it's a TCP packet */
     79		if (e->ip.proto != IPPROTO_TCP ||
     80		    (e->ip.invflags & XT_INV_PROTO)) {
     81			pr_info_ratelimited("TCP_RESET invalid for non-tcp\n");
     82			return -EINVAL;
     83		}
     84	}
     85	return 0;
     86}
     87
     88static struct xt_target reject_tg_reg __read_mostly = {
     89	.name		= "REJECT",
     90	.family		= NFPROTO_IPV4,
     91	.target		= reject_tg,
     92	.targetsize	= sizeof(struct ipt_reject_info),
     93	.table		= "filter",
     94	.hooks		= (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
     95			  (1 << NF_INET_LOCAL_OUT),
     96	.checkentry	= reject_tg_check,
     97	.me		= THIS_MODULE,
     98};
     99
    100static int __init reject_tg_init(void)
    101{
    102	return xt_register_target(&reject_tg_reg);
    103}
    104
    105static void __exit reject_tg_exit(void)
    106{
    107	xt_unregister_target(&reject_tg_reg);
    108}
    109
    110module_init(reject_tg_init);
    111module_exit(reject_tg_exit);