Contributors: 11
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Patrick McHardy |
394 |
65.02% |
4 |
16.67% |
| Fernando Fernandez Mancera |
85 |
14.03% |
3 |
12.50% |
| Florian Westphal |
65 |
10.73% |
3 |
12.50% |
| Liping Zhang |
16 |
2.64% |
2 |
8.33% |
| Pablo Neira Ayuso |
12 |
1.98% |
2 |
8.33% |
| Jesper Dangaard Brouer |
9 |
1.49% |
2 |
8.33% |
| Gao Feng |
9 |
1.49% |
1 |
4.17% |
| Yasuyuki Kozakai |
5 |
0.83% |
2 |
8.33% |
| Rob Gill |
5 |
0.83% |
1 |
4.17% |
| Eric W. Biedermann |
4 |
0.66% |
3 |
12.50% |
| Thomas Gleixner |
2 |
0.33% |
1 |
4.17% |
| Total |
606 |
|
24 |
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2013 Patrick McHardy <kaber@trash.net>
*/
#include <linux/netfilter_ipv4/ip_tables.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter/xt_SYNPROXY.h>
#include <net/netfilter/nf_synproxy.h>
static unsigned int
synproxy_tg4(struct sk_buff *skb, const struct xt_action_param *par)
{
const struct xt_synproxy_info *info = par->targinfo;
struct net *net = xt_net(par);
struct synproxy_net *snet = synproxy_pernet(net);
struct synproxy_options opts = {};
struct tcphdr *th, _th;
if (nf_ip_checksum(skb, xt_hooknum(par), par->thoff, IPPROTO_TCP))
return NF_DROP;
th = skb_header_pointer(skb, par->thoff, sizeof(_th), &_th);
if (th == NULL)
return NF_DROP;
if (!synproxy_parse_options(skb, par->thoff, th, &opts))
return NF_DROP;
if (th->syn && !(th->ack || th->fin || th->rst)) {
/* Initial SYN from client */
this_cpu_inc(snet->stats->syn_received);
if (th->ece && th->cwr)
opts.options |= XT_SYNPROXY_OPT_ECN;
opts.options &= info->options;
opts.mss_encode = opts.mss_option;
opts.mss_option = info->mss;
if (opts.options & XT_SYNPROXY_OPT_TIMESTAMP)
synproxy_init_timestamp_cookie(info, &opts);
else
opts.options &= ~(XT_SYNPROXY_OPT_WSCALE |
XT_SYNPROXY_OPT_SACK_PERM |
XT_SYNPROXY_OPT_ECN);
synproxy_send_client_synack(net, skb, th, &opts);
consume_skb(skb);
return NF_STOLEN;
} else if (th->ack && !(th->fin || th->rst || th->syn)) {
/* ACK from client */
if (synproxy_recv_client_ack(net, skb, th, &opts, ntohl(th->seq))) {
consume_skb(skb);
return NF_STOLEN;
} else {
return NF_DROP;
}
}
return XT_CONTINUE;
}
static int synproxy_tg4_check(const struct xt_tgchk_param *par)
{
struct synproxy_net *snet = synproxy_pernet(par->net);
const struct ipt_entry *e = par->entryinfo;
int err;
if (e->ip.proto != IPPROTO_TCP ||
e->ip.invflags & XT_INV_PROTO)
return -EINVAL;
err = nf_ct_netns_get(par->net, par->family);
if (err)
return err;
err = nf_synproxy_ipv4_init(snet, par->net);
if (err) {
nf_ct_netns_put(par->net, par->family);
return err;
}
return err;
}
static void synproxy_tg4_destroy(const struct xt_tgdtor_param *par)
{
struct synproxy_net *snet = synproxy_pernet(par->net);
nf_synproxy_ipv4_fini(snet, par->net);
nf_ct_netns_put(par->net, par->family);
}
static struct xt_target synproxy_tg4_reg __read_mostly = {
.name = "SYNPROXY",
.family = NFPROTO_IPV4,
.hooks = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD),
.target = synproxy_tg4,
.targetsize = sizeof(struct xt_synproxy_info),
.checkentry = synproxy_tg4_check,
.destroy = synproxy_tg4_destroy,
.me = THIS_MODULE,
};
static int __init synproxy_tg4_init(void)
{
return xt_register_target(&synproxy_tg4_reg);
}
static void __exit synproxy_tg4_exit(void)
{
xt_unregister_target(&synproxy_tg4_reg);
}
module_init(synproxy_tg4_init);
module_exit(synproxy_tg4_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
MODULE_DESCRIPTION("Intercept TCP connections and establish them using syncookies");