cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

iptable_mangle.c (3502B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
      4 *
      5 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
      6 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
      7 */
      8#include <linux/module.h>
      9#include <linux/netfilter_ipv4/ip_tables.h>
     10#include <linux/netdevice.h>
     11#include <linux/skbuff.h>
     12#include <linux/slab.h>
     13#include <net/sock.h>
     14#include <net/route.h>
     15#include <linux/ip.h>
     16#include <net/ip.h>
     17
     18MODULE_LICENSE("GPL");
     19MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
     20MODULE_DESCRIPTION("iptables mangle table");
     21
     22#define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
     23			    (1 << NF_INET_LOCAL_IN) | \
     24			    (1 << NF_INET_FORWARD) | \
     25			    (1 << NF_INET_LOCAL_OUT) | \
     26			    (1 << NF_INET_POST_ROUTING))
     27
     28static const struct xt_table packet_mangler = {
     29	.name		= "mangle",
     30	.valid_hooks	= MANGLE_VALID_HOOKS,
     31	.me		= THIS_MODULE,
     32	.af		= NFPROTO_IPV4,
     33	.priority	= NF_IP_PRI_MANGLE,
     34};
     35
     36static unsigned int
     37ipt_mangle_out(void *priv, struct sk_buff *skb, const struct nf_hook_state *state)
     38{
     39	unsigned int ret;
     40	const struct iphdr *iph;
     41	u_int8_t tos;
     42	__be32 saddr, daddr;
     43	u_int32_t mark;
     44	int err;
     45
     46	/* Save things which could affect route */
     47	mark = skb->mark;
     48	iph = ip_hdr(skb);
     49	saddr = iph->saddr;
     50	daddr = iph->daddr;
     51	tos = iph->tos;
     52
     53	ret = ipt_do_table(priv, skb, state);
     54	/* Reroute for ANY change. */
     55	if (ret != NF_DROP && ret != NF_STOLEN) {
     56		iph = ip_hdr(skb);
     57
     58		if (iph->saddr != saddr ||
     59		    iph->daddr != daddr ||
     60		    skb->mark != mark ||
     61		    iph->tos != tos) {
     62			err = ip_route_me_harder(state->net, state->sk, skb, RTN_UNSPEC);
     63			if (err < 0)
     64				ret = NF_DROP_ERR(err);
     65		}
     66	}
     67
     68	return ret;
     69}
     70
     71/* The work comes in here from netfilter.c. */
     72static unsigned int
     73iptable_mangle_hook(void *priv,
     74		     struct sk_buff *skb,
     75		     const struct nf_hook_state *state)
     76{
     77	if (state->hook == NF_INET_LOCAL_OUT)
     78		return ipt_mangle_out(priv, skb, state);
     79	return ipt_do_table(priv, skb, state);
     80}
     81
     82static struct nf_hook_ops *mangle_ops __read_mostly;
     83static int iptable_mangle_table_init(struct net *net)
     84{
     85	struct ipt_replace *repl;
     86	int ret;
     87
     88	repl = ipt_alloc_initial_table(&packet_mangler);
     89	if (repl == NULL)
     90		return -ENOMEM;
     91	ret = ipt_register_table(net, &packet_mangler, repl, mangle_ops);
     92	kfree(repl);
     93	return ret;
     94}
     95
     96static void __net_exit iptable_mangle_net_pre_exit(struct net *net)
     97{
     98	ipt_unregister_table_pre_exit(net, "mangle");
     99}
    100
    101static void __net_exit iptable_mangle_net_exit(struct net *net)
    102{
    103	ipt_unregister_table_exit(net, "mangle");
    104}
    105
    106static struct pernet_operations iptable_mangle_net_ops = {
    107	.pre_exit = iptable_mangle_net_pre_exit,
    108	.exit = iptable_mangle_net_exit,
    109};
    110
    111static int __init iptable_mangle_init(void)
    112{
    113	int ret = xt_register_template(&packet_mangler,
    114				       iptable_mangle_table_init);
    115	if (ret < 0)
    116		return ret;
    117
    118	mangle_ops = xt_hook_ops_alloc(&packet_mangler, iptable_mangle_hook);
    119	if (IS_ERR(mangle_ops)) {
    120		xt_unregister_template(&packet_mangler);
    121		ret = PTR_ERR(mangle_ops);
    122		return ret;
    123	}
    124
    125	ret = register_pernet_subsys(&iptable_mangle_net_ops);
    126	if (ret < 0) {
    127		xt_unregister_template(&packet_mangler);
    128		kfree(mangle_ops);
    129		return ret;
    130	}
    131
    132	return ret;
    133}
    134
    135static void __exit iptable_mangle_fini(void)
    136{
    137	unregister_pernet_subsys(&iptable_mangle_net_ops);
    138	xt_unregister_template(&packet_mangler);
    139	kfree(mangle_ops);
    140}
    141
    142module_init(iptable_mangle_init);
    143module_exit(iptable_mangle_fini);