1 files changed, 542 insertions, 0 deletions

diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
new file mode 100644
index 000000000..30ad9554b
--- /dev/null
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -0,0 +1,542 @@
+
+/* (C) 1999-2001 Paul `Rusty' Russell
+ * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
+ * (C) 2006-2012 Patrick McHardy <kaber@trash.net>
+ *
+ * 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/types.h>
+#include <linux/ip.h>
+#include <linux/netfilter.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/icmp.h>
+#include <linux/sysctl.h>
+#include <net/route.h>
+#include <net/ip.h>
+
+#include <linux/netfilter_ipv4.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_helper.h>
+#include <net/netfilter/nf_conntrack_l4proto.h>
+#include <net/netfilter/nf_conntrack_l3proto.h>
+#include <net/netfilter/nf_conntrack_zones.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack_seqadj.h>
+#include <net/netfilter/ipv4/nf_conntrack_ipv4.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
+#include <net/netfilter/nf_log.h>
+
+static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
+			      struct nf_conntrack_tuple *tuple)
+{
+	const __be32 *ap;
+	__be32 _addrs[2];
+	ap = skb_header_pointer(skb, nhoff + offsetof(struct iphdr, saddr),
+				sizeof(u_int32_t) * 2, _addrs);
+	if (ap == NULL)
+		return false;
+
+	tuple->src.u3.ip = ap[0];
+	tuple->dst.u3.ip = ap[1];
+
+	return true;
+}
+
+static bool ipv4_invert_tuple(struct nf_conntrack_tuple *tuple,
+			      const struct nf_conntrack_tuple *orig)
+{
+	tuple->src.u3.ip = orig->dst.u3.ip;
+	tuple->dst.u3.ip = orig->src.u3.ip;
+
+	return true;
+}
+
+static void ipv4_print_tuple(struct seq_file *s,
+			    const struct nf_conntrack_tuple *tuple)
+{
+	seq_printf(s, "src=%pI4 dst=%pI4 ",
+		   &tuple->src.u3.ip, &tuple->dst.u3.ip);
+}
+
+static int ipv4_get_l4proto(const struct sk_buff *skb, unsigned int nhoff,
+			    unsigned int *dataoff, u_int8_t *protonum)
+{
+	const struct iphdr *iph;
+	struct iphdr _iph;
+
+	iph = skb_header_pointer(skb, nhoff, sizeof(_iph), &_iph);
+	if (iph == NULL)
+		return -NF_ACCEPT;
+
+	/* Conntrack defragments packets, we might still see fragments
+	 * inside ICMP packets though. */
+	if (iph->frag_off & htons(IP_OFFSET))
+		return -NF_ACCEPT;
+
+	*dataoff = nhoff + (iph->ihl << 2);
+	*protonum = iph->protocol;
+
+	/* Check bogus IP headers */
+	if (*dataoff > skb->len) {
+		pr_debug("nf_conntrack_ipv4: bogus IPv4 packet: "
+			 "nhoff %u, ihl %u, skblen %u\n",
+			 nhoff, iph->ihl << 2, skb->len);
+		return -NF_ACCEPT;
+	}
+
+	return NF_ACCEPT;
+}
+
+static unsigned int ipv4_helper(const struct nf_hook_ops *ops,
+				struct sk_buff *skb,
+				const struct nf_hook_state *state)
+{
+	struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+	const struct nf_conn_help *help;
+	const struct nf_conntrack_helper *helper;
+
+	/* This is where we call the helper: as the packet goes out. */
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
+		return NF_ACCEPT;
+
+	help = nfct_help(ct);
+	if (!help)
+		return NF_ACCEPT;
+
+	/* rcu_read_lock()ed by nf_hook_slow */
+	helper = rcu_dereference(help->helper);
+	if (!helper)
+		return NF_ACCEPT;
+
+	return helper->help(skb, skb_network_offset(skb) + ip_hdrlen(skb),
+			    ct, ctinfo);
+}
+
+static unsigned int ipv4_confirm(const struct nf_hook_ops *ops,
+				 struct sk_buff *skb,
+				 const struct nf_hook_state *state)
+{
+	struct nf_conn *ct;
+	enum ip_conntrack_info ctinfo;
+
+	ct = nf_ct_get(skb, &ctinfo);
+	if (!ct || ctinfo == IP_CT_RELATED_REPLY)
+		goto out;
+
+	/* adjust seqs for loopback traffic only in outgoing direction */
+	if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
+	    !nf_is_loopback_packet(skb)) {
+		if (!nf_ct_seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) {
+			NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
+			return NF_DROP;
+		}
+	}
+out:
+	/* We've seen it coming out the other side: confirm it */
+	return nf_conntrack_confirm(skb);
+}
+
+static unsigned int ipv4_conntrack_in(const struct nf_hook_ops *ops,
+				      struct sk_buff *skb,
+				      const struct nf_hook_state *state)
+{
+	return nf_conntrack_in(dev_net(state->in), PF_INET, ops->hooknum, skb);
+}
+
+static unsigned int ipv4_conntrack_local(const struct nf_hook_ops *ops,
+					 struct sk_buff *skb,
+					 const struct nf_hook_state *state)
+{
+	/* root is playing with raw sockets. */
+	if (skb->len < sizeof(struct iphdr) ||
+	    ip_hdrlen(skb) < sizeof(struct iphdr))
+		return NF_ACCEPT;
+	return nf_conntrack_in(dev_net(state->out), PF_INET, ops->hooknum, skb);
+}
+
+/* Connection tracking may drop packets, but never alters them, so
+   make it the first hook. */
+static struct nf_hook_ops ipv4_conntrack_ops[] __read_mostly = {
+	{
+		.hook		= ipv4_conntrack_in,
+		.owner		= THIS_MODULE,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_PRE_ROUTING,
+		.priority	= NF_IP_PRI_CONNTRACK,
+	},
+	{
+		.hook		= ipv4_conntrack_local,
+		.owner		= THIS_MODULE,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_LOCAL_OUT,
+		.priority	= NF_IP_PRI_CONNTRACK,
+	},
+	{
+		.hook		= ipv4_helper,
+		.owner		= THIS_MODULE,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_POST_ROUTING,
+		.priority	= NF_IP_PRI_CONNTRACK_HELPER,
+	},
+	{
+		.hook		= ipv4_confirm,
+		.owner		= THIS_MODULE,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_POST_ROUTING,
+		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM,
+	},
+	{
+		.hook		= ipv4_helper,
+		.owner		= THIS_MODULE,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_LOCAL_IN,
+		.priority	= NF_IP_PRI_CONNTRACK_HELPER,
+	},
+	{
+		.hook		= ipv4_confirm,
+		.owner		= THIS_MODULE,
+		.pf		= NFPROTO_IPV4,
+		.hooknum	= NF_INET_LOCAL_IN,
+		.priority	= NF_IP_PRI_CONNTRACK_CONFIRM,
+	},
+};
+
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
+static int log_invalid_proto_min = 0;
+static int log_invalid_proto_max = 255;
+
+static struct ctl_table ip_ct_sysctl_table[] = {
+	{
+		.procname	= "ip_conntrack_max",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "ip_conntrack_count",
+		.maxlen		= sizeof(int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "ip_conntrack_buckets",
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0444,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "ip_conntrack_checksum",
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+	},
+	{
+		.procname	= "ip_conntrack_log_invalid",
+		.maxlen		= sizeof(unsigned int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &log_invalid_proto_min,
+		.extra2		= &log_invalid_proto_max,
+	},
+	{ }
+};
+#endif /* CONFIG_SYSCTL && CONFIG_NF_CONNTRACK_PROC_COMPAT */
+
+/* Fast function for those who don't want to parse /proc (and I don't
+   blame them). */
+/* Reversing the socket's dst/src point of view gives us the reply
+   mapping. */
+static int
+getorigdst(struct sock *sk, int optval, void __user *user, int *len)
+{
+	const struct inet_sock *inet = inet_sk(sk);
+	const struct nf_conntrack_tuple_hash *h;
+	struct nf_conntrack_tuple tuple;
+
+	memset(&tuple, 0, sizeof(tuple));
+	tuple.src.u3.ip = inet->inet_rcv_saddr;
+	tuple.src.u.tcp.port = inet->inet_sport;
+	tuple.dst.u3.ip = inet->inet_daddr;
+	tuple.dst.u.tcp.port = inet->inet_dport;
+	tuple.src.l3num = PF_INET;
+	tuple.dst.protonum = sk->sk_protocol;
+
+	/* We only do TCP and SCTP at the moment: is there a better way? */
+	if (sk->sk_protocol != IPPROTO_TCP && sk->sk_protocol != IPPROTO_SCTP) {
+		pr_debug("SO_ORIGINAL_DST: Not a TCP/SCTP socket\n");
+		return -ENOPROTOOPT;
+	}
+
+	if ((unsigned int) *len < sizeof(struct sockaddr_in)) {
+		pr_debug("SO_ORIGINAL_DST: len %d not %Zu\n",
+			 *len, sizeof(struct sockaddr_in));
+		return -EINVAL;
+	}
+
+	h = nf_conntrack_find_get(sock_net(sk), NF_CT_DEFAULT_ZONE, &tuple);
+	if (h) {
+		struct sockaddr_in sin;
+		struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
+
+		sin.sin_family = AF_INET;
+		sin.sin_port = ct->tuplehash[IP_CT_DIR_ORIGINAL]
+			.tuple.dst.u.tcp.port;
+		sin.sin_addr.s_addr = ct->tuplehash[IP_CT_DIR_ORIGINAL]
+			.tuple.dst.u3.ip;
+		memset(sin.sin_zero, 0, sizeof(sin.sin_zero));
+
+		pr_debug("SO_ORIGINAL_DST: %pI4 %u\n",
+			 &sin.sin_addr.s_addr, ntohs(sin.sin_port));
+		nf_ct_put(ct);
+		if (copy_to_user(user, &sin, sizeof(sin)) != 0)
+			return -EFAULT;
+		else
+			return 0;
+	}
+	pr_debug("SO_ORIGINAL_DST: Can't find %pI4/%u-%pI4/%u.\n",
+		 &tuple.src.u3.ip, ntohs(tuple.src.u.tcp.port),
+		 &tuple.dst.u3.ip, ntohs(tuple.dst.u.tcp.port));
+	return -ENOENT;
+}
+
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
+
+#include <linux/netfilter/nfnetlink.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static int ipv4_tuple_to_nlattr(struct sk_buff *skb,
+				const struct nf_conntrack_tuple *tuple)
+{
+	if (nla_put_in_addr(skb, CTA_IP_V4_SRC, tuple->src.u3.ip) ||
+	    nla_put_in_addr(skb, CTA_IP_V4_DST, tuple->dst.u3.ip))
+		goto nla_put_failure;
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static const struct nla_policy ipv4_nla_policy[CTA_IP_MAX+1] = {
+	[CTA_IP_V4_SRC]	= { .type = NLA_U32 },
+	[CTA_IP_V4_DST]	= { .type = NLA_U32 },
+};
+
+static int ipv4_nlattr_to_tuple(struct nlattr *tb[],
+				struct nf_conntrack_tuple *t)
+{
+	if (!tb[CTA_IP_V4_SRC] || !tb[CTA_IP_V4_DST])
+		return -EINVAL;
+
+	t->src.u3.ip = nla_get_in_addr(tb[CTA_IP_V4_SRC]);
+	t->dst.u3.ip = nla_get_in_addr(tb[CTA_IP_V4_DST]);
+
+	return 0;
+}
+
+static int ipv4_nlattr_tuple_size(void)
+{
+	return nla_policy_len(ipv4_nla_policy, CTA_IP_MAX + 1);
+}
+#endif
+
+static struct nf_sockopt_ops so_getorigdst = {
+	.pf		= PF_INET,
+	.get_optmin	= SO_ORIGINAL_DST,
+	.get_optmax	= SO_ORIGINAL_DST+1,
+	.get		= getorigdst,
+	.owner		= THIS_MODULE,
+};
+
+static int ipv4_init_net(struct net *net)
+{
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
+	struct nf_ip_net *in = &net->ct.nf_ct_proto;
+	in->ctl_table = kmemdup(ip_ct_sysctl_table,
+				sizeof(ip_ct_sysctl_table),
+				GFP_KERNEL);
+	if (!in->ctl_table)
+		return -ENOMEM;
+
+	in->ctl_table[0].data = &nf_conntrack_max;
+	in->ctl_table[1].data = &net->ct.count;
+	in->ctl_table[2].data = &net->ct.htable_size;
+	in->ctl_table[3].data = &net->ct.sysctl_checksum;
+	in->ctl_table[4].data = &net->ct.sysctl_log_invalid;
+#endif
+	return 0;
+}
+
+struct nf_conntrack_l3proto nf_conntrack_l3proto_ipv4 __read_mostly = {
+	.l3proto	 = PF_INET,
+	.name		 = "ipv4",
+	.pkt_to_tuple	 = ipv4_pkt_to_tuple,
+	.invert_tuple	 = ipv4_invert_tuple,
+	.print_tuple	 = ipv4_print_tuple,
+	.get_l4proto	 = ipv4_get_l4proto,
+#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
+	.tuple_to_nlattr = ipv4_tuple_to_nlattr,
+	.nlattr_tuple_size = ipv4_nlattr_tuple_size,
+	.nlattr_to_tuple = ipv4_nlattr_to_tuple,
+	.nla_policy	 = ipv4_nla_policy,
+#endif
+#if defined(CONFIG_SYSCTL) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
+	.ctl_table_path  = "net/ipv4/netfilter",
+#endif
+	.init_net	 = ipv4_init_net,
+	.me		 = THIS_MODULE,
+};
+
+module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
+		  &nf_conntrack_htable_size, 0600);
+
+MODULE_ALIAS("nf_conntrack-" __stringify(AF_INET));
+MODULE_ALIAS("ip_conntrack");
+MODULE_LICENSE("GPL");
+
+static int ipv4_net_init(struct net *net)
+{
+	int ret = 0;
+
+	ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_tcp4);
+	if (ret < 0) {
+		pr_err("nf_conntrack_tcp4: pernet registration failed\n");
+		goto out_tcp;
+	}
+	ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_udp4);
+	if (ret < 0) {
+		pr_err("nf_conntrack_udp4: pernet registration failed\n");
+		goto out_udp;
+	}
+	ret = nf_ct_l4proto_pernet_register(net, &nf_conntrack_l4proto_icmp);
+	if (ret < 0) {
+		pr_err("nf_conntrack_icmp4: pernet registration failed\n");
+		goto out_icmp;
+	}
+	ret = nf_ct_l3proto_pernet_register(net, &nf_conntrack_l3proto_ipv4);
+	if (ret < 0) {
+		pr_err("nf_conntrack_ipv4: pernet registration failed\n");
+		goto out_ipv4;
+	}
+	return 0;
+out_ipv4:
+	nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
+out_icmp:
+	nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
+out_udp:
+	nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
+out_tcp:
+	return ret;
+}
+
+static void ipv4_net_exit(struct net *net)
+{
+	nf_ct_l3proto_pernet_unregister(net, &nf_conntrack_l3proto_ipv4);
+	nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_icmp);
+	nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_udp4);
+	nf_ct_l4proto_pernet_unregister(net, &nf_conntrack_l4proto_tcp4);
+}
+
+static struct pernet_operations ipv4_net_ops = {
+	.init = ipv4_net_init,
+	.exit = ipv4_net_exit,
+};
+
+static int __init nf_conntrack_l3proto_ipv4_init(void)
+{
+	int ret = 0;
+
+	need_conntrack();
+	nf_defrag_ipv4_enable();
+
+	ret = nf_register_sockopt(&so_getorigdst);
+	if (ret < 0) {
+		printk(KERN_ERR "Unable to register netfilter socket option\n");
+		return ret;
+	}
+
+	ret = register_pernet_subsys(&ipv4_net_ops);
+	if (ret < 0) {
+		pr_err("nf_conntrack_ipv4: can't register pernet ops\n");
+		goto cleanup_sockopt;
+	}
+
+	ret = nf_register_hooks(ipv4_conntrack_ops,
+				ARRAY_SIZE(ipv4_conntrack_ops));
+	if (ret < 0) {
+		pr_err("nf_conntrack_ipv4: can't register hooks.\n");
+		goto cleanup_pernet;
+	}
+
+	ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_tcp4);
+	if (ret < 0) {
+		pr_err("nf_conntrack_ipv4: can't register tcp4 proto.\n");
+		goto cleanup_hooks;
+	}
+
+	ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_udp4);
+	if (ret < 0) {
+		pr_err("nf_conntrack_ipv4: can't register udp4 proto.\n");
+		goto cleanup_tcp4;
+	}
+
+	ret = nf_ct_l4proto_register(&nf_conntrack_l4proto_icmp);
+	if (ret < 0) {
+		pr_err("nf_conntrack_ipv4: can't register icmpv4 proto.\n");
+		goto cleanup_udp4;
+	}
+
+	ret = nf_ct_l3proto_register(&nf_conntrack_l3proto_ipv4);
+	if (ret < 0) {
+		pr_err("nf_conntrack_ipv4: can't register ipv4 proto.\n");
+		goto cleanup_icmpv4;
+	}
+
+#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
+	ret = nf_conntrack_ipv4_compat_init();
+	if (ret < 0)
+		goto cleanup_proto;
+#endif
+	return ret;
+#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
+ cleanup_proto:
+	nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
+#endif
+ cleanup_icmpv4:
+	nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
+ cleanup_udp4:
+	nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
+ cleanup_tcp4:
+	nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
+ cleanup_hooks:
+	nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
+ cleanup_pernet:
+	unregister_pernet_subsys(&ipv4_net_ops);
+ cleanup_sockopt:
+	nf_unregister_sockopt(&so_getorigdst);
+	return ret;
+}
+
+static void __exit nf_conntrack_l3proto_ipv4_fini(void)
+{
+	synchronize_net();
+#if defined(CONFIG_PROC_FS) && defined(CONFIG_NF_CONNTRACK_PROC_COMPAT)
+	nf_conntrack_ipv4_compat_fini();
+#endif
+	nf_ct_l3proto_unregister(&nf_conntrack_l3proto_ipv4);
+	nf_ct_l4proto_unregister(&nf_conntrack_l4proto_icmp);
+	nf_ct_l4proto_unregister(&nf_conntrack_l4proto_udp4);
+	nf_ct_l4proto_unregister(&nf_conntrack_l4proto_tcp4);
+	nf_unregister_hooks(ipv4_conntrack_ops, ARRAY_SIZE(ipv4_conntrack_ops));
+	unregister_pernet_subsys(&ipv4_net_ops);
+	nf_unregister_sockopt(&so_getorigdst);
+}
+
+module_init(nf_conntrack_l3proto_ipv4_init);
+module_exit(nf_conntrack_l3proto_ipv4_fini);