[mirror_ubuntu-bionic-kernel.git] / net / netfilter / xt_socket.c

/*
 * Transparent proxy support for Linux/iptables
 *
 * Copyright (C) 2007-2008 BalaBit IT Ltd.
 * Author: Krisztian Kovacs
 *
 * 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/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <net/tcp.h>
#include <net/udp.h>
#include <net/icmp.h>
#include <net/sock.h>
#include <net/inet_sock.h>
#include <net/netfilter/ipv4/nf_defrag_ipv4.h>

#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
#define XT_SOCKET_HAVE_IPV6 1
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/inet6_hashtables.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#endif

#include <linux/netfilter/xt_socket.h>

#if IS_ENABLED(CONFIG_NF_CONNTRACK)
#define XT_SOCKET_HAVE_CONNTRACK 1
#include <net/netfilter/nf_conntrack.h>
#endif

static void
xt_socket_put_sk(struct sock *sk)
{
	if (sk->sk_state == TCP_TIME_WAIT)
		inet_twsk_put(inet_twsk(sk));
	else
		sock_put(sk);
}

static int
extract_icmp4_fields(const struct sk_buff *skb,
		    u8 *protocol,
		    __be32 *raddr,
		    __be32 *laddr,
		    __be16 *rport,
		    __be16 *lport)
{
	unsigned int outside_hdrlen = ip_hdrlen(skb);
	struct iphdr *inside_iph, _inside_iph;
	struct icmphdr *icmph, _icmph;
	__be16 *ports, _ports[2];

	icmph = skb_header_pointer(skb, outside_hdrlen,
				   sizeof(_icmph), &_icmph);
	if (icmph == NULL)
		return 1;

	switch (icmph->type) {
	case ICMP_DEST_UNREACH:
	case ICMP_SOURCE_QUENCH:
	case ICMP_REDIRECT:
	case ICMP_TIME_EXCEEDED:
	case ICMP_PARAMETERPROB:
		break;
	default:
		return 1;
	}

	inside_iph = skb_header_pointer(skb, outside_hdrlen +
					sizeof(struct icmphdr),
					sizeof(_inside_iph), &_inside_iph);
	if (inside_iph == NULL)
		return 1;

	if (inside_iph->protocol != IPPROTO_TCP &&
	    inside_iph->protocol != IPPROTO_UDP)
		return 1;

	ports = skb_header_pointer(skb, outside_hdrlen +
				   sizeof(struct icmphdr) +
				   (inside_iph->ihl << 2),
				   sizeof(_ports), &_ports);
	if (ports == NULL)
		return 1;

	/* the inside IP packet is the one quoted from our side, thus
	 * its saddr is the local address */
	*protocol = inside_iph->protocol;
	*laddr = inside_iph->saddr;
	*lport = ports[0];
	*raddr = inside_iph->daddr;
	*rport = ports[1];

	return 0;
}

/* "socket" match based redirection (no specific rule)
 * ===================================================
 *
 * There are connections with dynamic endpoints (e.g. FTP data
 * connection) that the user is unable to add explicit rules
 * for. These are taken care of by a generic "socket" rule. It is
 * assumed that the proxy application is trusted to open such
 * connections without explicit iptables rule (except of course the
 * generic 'socket' rule). In this case the following sockets are
 * matched in preference order:
 *
 *   - match: if there's a fully established connection matching the
 *     _packet_ tuple
 *
 *   - match: if there's a non-zero bound listener (possibly with a
 *     non-local address) We don't accept zero-bound listeners, since
 *     then local services could intercept traffic going through the
 *     box.
 */
static struct sock *
xt_socket_get_sock_v4(struct net *net, const u8 protocol,
		      const __be32 saddr, const __be32 daddr,
		      const __be16 sport, const __be16 dport,
		      const struct net_device *in)
{
	switch (protocol) {
	case IPPROTO_TCP:
		return __inet_lookup(net, &tcp_hashinfo,
				     saddr, sport, daddr, dport,
				     in->ifindex);
	case IPPROTO_UDP:
		return udp4_lib_lookup(net, saddr, sport, daddr, dport,
				       in->ifindex);
	}
	return NULL;
}

static bool
socket_match(const struct sk_buff *skb, struct xt_action_param *par,
	     const struct xt_socket_mtinfo1 *info)
{
	const struct iphdr *iph = ip_hdr(skb);
	struct udphdr _hdr, *hp = NULL;
	struct sock *sk = skb->sk;
	__be32 uninitialized_var(daddr), uninitialized_var(saddr);
	__be16 uninitialized_var(dport), uninitialized_var(sport);
	u8 uninitialized_var(protocol);
#ifdef XT_SOCKET_HAVE_CONNTRACK
	struct nf_conn const *ct;
	enum ip_conntrack_info ctinfo;
#endif

	if (iph->protocol == IPPROTO_UDP || iph->protocol == IPPROTO_TCP) {
		hp = skb_header_pointer(skb, ip_hdrlen(skb),
					sizeof(_hdr), &_hdr);
		if (hp == NULL)
			return false;

		protocol = iph->protocol;
		saddr = iph->saddr;
		sport = hp->source;
		daddr = iph->daddr;
		dport = hp->dest;

	} else if (iph->protocol == IPPROTO_ICMP) {
		if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr,
					&sport, &dport))
			return false;
	} else {
		return false;
	}

#ifdef XT_SOCKET_HAVE_CONNTRACK
	/* Do the lookup with the original socket address in case this is a
	 * reply packet of an established SNAT-ted connection. */

	ct = nf_ct_get(skb, &ctinfo);
	if (ct && !nf_ct_is_untracked(ct) &&
	    ((iph->protocol != IPPROTO_ICMP &&
	      ctinfo == IP_CT_ESTABLISHED_REPLY) ||
	     (iph->protocol == IPPROTO_ICMP &&
	      ctinfo == IP_CT_RELATED_REPLY)) &&
	    (ct->status & IPS_SRC_NAT_DONE)) {

		daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
		dport = (iph->protocol == IPPROTO_TCP) ?
			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port :
			ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
	}
#endif

	if (!sk)
		sk = xt_socket_get_sock_v4(dev_net(skb->dev), protocol,
					   saddr, daddr, sport, dport,
					   par->in);
	if (sk) {
		bool wildcard;
		bool transparent = true;

		/* Ignore sockets listening on INADDR_ANY,
		 * unless XT_SOCKET_NOWILDCARD is set
		 */
		wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
			    sk->sk_state != TCP_TIME_WAIT &&
			    inet_sk(sk)->inet_rcv_saddr == 0);

		/* Ignore non-transparent sockets,
		   if XT_SOCKET_TRANSPARENT is used */
		if (info->flags & XT_SOCKET_TRANSPARENT)
			transparent = ((sk->sk_state != TCP_TIME_WAIT &&
					inet_sk(sk)->transparent) ||
				       (sk->sk_state == TCP_TIME_WAIT &&
					inet_twsk(sk)->tw_transparent));

		if (sk != skb->sk)
			xt_socket_put_sk(sk);

		if (wildcard || !transparent)
			sk = NULL;
	}

	pr_debug("proto %hhu %pI4:%hu -> %pI4:%hu (orig %pI4:%hu) sock %p\n",
		 protocol, &saddr, ntohs(sport),
		 &daddr, ntohs(dport),
		 &iph->daddr, hp ? ntohs(hp->dest) : 0, sk);

	return (sk != NULL);
}

static bool
socket_mt4_v0(const struct sk_buff *skb, struct xt_action_param *par)
{
	static struct xt_socket_mtinfo1 xt_info_v0 = {
		.flags = 0,
	};

	return socket_match(skb, par, &xt_info_v0);
}

static bool
socket_mt4_v1_v2(const struct sk_buff *skb, struct xt_action_param *par)
{
	return socket_match(skb, par, par->matchinfo);
}

#ifdef XT_SOCKET_HAVE_IPV6

static int
extract_icmp6_fields(const struct sk_buff *skb,
		     unsigned int outside_hdrlen,
		     int *protocol,
		     struct in6_addr **raddr,
		     struct in6_addr **laddr,
		     __be16 *rport,
		     __be16 *lport)
{
	struct ipv6hdr *inside_iph, _inside_iph;
	struct icmp6hdr *icmph, _icmph;
	__be16 *ports, _ports[2];
	u8 inside_nexthdr;
	__be16 inside_fragoff;
	int inside_hdrlen;

	icmph = skb_header_pointer(skb, outside_hdrlen,
				   sizeof(_icmph), &_icmph);
	if (icmph == NULL)
		return 1;

	if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK)
		return 1;

	inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph), sizeof(_inside_iph), &_inside_iph);
	if (inside_iph == NULL)
		return 1;
	inside_nexthdr = inside_iph->nexthdr;

	inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) + sizeof(_inside_iph),
					 &inside_nexthdr, &inside_fragoff);
	if (inside_hdrlen < 0)
		return 1; /* hjm: Packet has no/incomplete transport layer headers. */

	if (inside_nexthdr != IPPROTO_TCP &&
	    inside_nexthdr != IPPROTO_UDP)
		return 1;

	ports = skb_header_pointer(skb, inside_hdrlen,
				   sizeof(_ports), &_ports);
	if (ports == NULL)
		return 1;

	/* the inside IP packet is the one quoted from our side, thus
	 * its saddr is the local address */
	*protocol = inside_nexthdr;
	*laddr = &inside_iph->saddr;
	*lport = ports[0];
	*raddr = &inside_iph->daddr;
	*rport = ports[1];

	return 0;
}

static struct sock *
xt_socket_get_sock_v6(struct net *net, const u8 protocol,
		      const struct in6_addr *saddr, const struct in6_addr *daddr,
		      const __be16 sport, const __be16 dport,
		      const struct net_device *in)
{
	switch (protocol) {
	case IPPROTO_TCP:
		return inet6_lookup(net, &tcp_hashinfo,
				    saddr, sport, daddr, dport,
				    in->ifindex);
	case IPPROTO_UDP:
		return udp6_lib_lookup(net, saddr, sport, daddr, dport,
				       in->ifindex);
	}

	return NULL;
}

static bool
socket_mt6_v1_v2(const struct sk_buff *skb, struct xt_action_param *par)
{
	struct ipv6hdr *iph = ipv6_hdr(skb);
	struct udphdr _hdr, *hp = NULL;
	struct sock *sk = skb->sk;
	struct in6_addr *daddr = NULL, *saddr = NULL;
	__be16 uninitialized_var(dport), uninitialized_var(sport);
	int thoff = 0, uninitialized_var(tproto);
	const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;

	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
	if (tproto < 0) {
		pr_debug("unable to find transport header in IPv6 packet, dropping\n");
		return NF_DROP;
	}

	if (tproto == IPPROTO_UDP || tproto == IPPROTO_TCP) {
		hp = skb_header_pointer(skb, thoff,
					sizeof(_hdr), &_hdr);
		if (hp == NULL)
			return false;

		saddr = &iph->saddr;
		sport = hp->source;
		daddr = &iph->daddr;
		dport = hp->dest;

	} else if (tproto == IPPROTO_ICMPV6) {
		if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr,
					 &sport, &dport))
			return false;
	} else {
		return false;
	}

	if (!sk)
		sk = xt_socket_get_sock_v6(dev_net(skb->dev), tproto,
					   saddr, daddr, sport, dport,
					   par->in);
	if (sk) {
		bool wildcard;
		bool transparent = true;

		/* Ignore sockets listening on INADDR_ANY
		 * unless XT_SOCKET_NOWILDCARD is set
		 */
		wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
			    sk->sk_state != TCP_TIME_WAIT &&
			    ipv6_addr_any(&inet6_sk(sk)->rcv_saddr));

		/* Ignore non-transparent sockets,
		   if XT_SOCKET_TRANSPARENT is used */
		if (info->flags & XT_SOCKET_TRANSPARENT)
			transparent = ((sk->sk_state != TCP_TIME_WAIT &&
					inet_sk(sk)->transparent) ||
				       (sk->sk_state == TCP_TIME_WAIT &&
					inet_twsk(sk)->tw_transparent));

		if (sk != skb->sk)
			xt_socket_put_sk(sk);

		if (wildcard || !transparent)
			sk = NULL;
	}

	pr_debug("proto %hhd %pI6:%hu -> %pI6:%hu "
		 "(orig %pI6:%hu) sock %p\n",
		 tproto, saddr, ntohs(sport),
		 daddr, ntohs(dport),
		 &iph->daddr, hp ? ntohs(hp->dest) : 0, sk);

	return (sk != NULL);
}
#endif

static int socket_mt_v1_check(const struct xt_mtchk_param *par)
{
	const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;

	if (info->flags & ~XT_SOCKET_FLAGS_V1) {
		pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V1);
		return -EINVAL;
	}
	return 0;
}

static int socket_mt_v2_check(const struct xt_mtchk_param *par)
{
	const struct xt_socket_mtinfo2 *info = (struct xt_socket_mtinfo2 *) par->matchinfo;

	if (info->flags & ~XT_SOCKET_FLAGS_V2) {
		pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V2);
		return -EINVAL;
	}
	return 0;
}

static struct xt_match socket_mt_reg[] __read_mostly = {
	{
		.name		= "socket",
		.revision	= 0,
		.family		= NFPROTO_IPV4,
		.match		= socket_mt4_v0,
		.hooks		= (1 << NF_INET_PRE_ROUTING) |
				  (1 << NF_INET_LOCAL_IN),
		.me		= THIS_MODULE,
	},
	{
		.name		= "socket",
		.revision	= 1,
		.family		= NFPROTO_IPV4,
		.match		= socket_mt4_v1_v2,
		.checkentry	= socket_mt_v1_check,
		.matchsize	= sizeof(struct xt_socket_mtinfo1),
		.hooks		= (1 << NF_INET_PRE_ROUTING) |
				  (1 << NF_INET_LOCAL_IN),
		.me		= THIS_MODULE,
	},
#ifdef XT_SOCKET_HAVE_IPV6
	{
		.name		= "socket",
		.revision	= 1,
		.family		= NFPROTO_IPV6,
		.match		= socket_mt6_v1_v2,
		.checkentry	= socket_mt_v1_check,
		.matchsize	= sizeof(struct xt_socket_mtinfo1),
		.hooks		= (1 << NF_INET_PRE_ROUTING) |
				  (1 << NF_INET_LOCAL_IN),
		.me		= THIS_MODULE,
	},
#endif
	{
		.name		= "socket",
		.revision	= 2,
		.family		= NFPROTO_IPV4,
		.match		= socket_mt4_v1_v2,
		.checkentry	= socket_mt_v2_check,
		.matchsize	= sizeof(struct xt_socket_mtinfo1),
		.hooks		= (1 << NF_INET_PRE_ROUTING) |
				  (1 << NF_INET_LOCAL_IN),
		.me		= THIS_MODULE,
	},
#ifdef XT_SOCKET_HAVE_IPV6
	{
		.name		= "socket",
		.revision	= 2,
		.family		= NFPROTO_IPV6,
		.match		= socket_mt6_v1_v2,
		.checkentry	= socket_mt_v2_check,
		.matchsize	= sizeof(struct xt_socket_mtinfo1),
		.hooks		= (1 << NF_INET_PRE_ROUTING) |
				  (1 << NF_INET_LOCAL_IN),
		.me		= THIS_MODULE,
	},
#endif
};

static int __init socket_mt_init(void)
{
	nf_defrag_ipv4_enable();
#ifdef XT_SOCKET_HAVE_IPV6
	nf_defrag_ipv6_enable();
#endif

	return xt_register_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
}

static void __exit socket_mt_exit(void)
{
	xt_unregister_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
}

module_init(socket_mt_init);
module_exit(socket_mt_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler");
MODULE_DESCRIPTION("x_tables socket match module");
MODULE_ALIAS("ipt_socket");
MODULE_ALIAS("ip6t_socket");
Commit	Line	Data
136cdc71 KK	1	/*
	2	* Transparent proxy support for Linux/iptables
	3	*
	4	* Copyright (C) 2007-2008 BalaBit IT Ltd.
	5	* Author: Krisztian Kovacs
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*
	11	*/
ff67e4e4	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
136cdc71 KK	13	#include <linux/module.h>
	14	#include <linux/skbuff.h>
	15	#include <linux/netfilter/x_tables.h>
	16	#include <linux/netfilter_ipv4/ip_tables.h>
	17	#include <net/tcp.h>
	18	#include <net/udp.h>
	19	#include <net/icmp.h>
	20	#include <net/sock.h>
	21	#include <net/inet_sock.h>
136cdc71	22	#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
f6318e55	23
c0cd1156	24	#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
f6318e55 KK	25	#define XT_SOCKET_HAVE_IPV6 1
f6318e55 KK	26	#include <linux/netfilter_ipv6/ip6_tables.h>
93742cf8	27	#include <net/inet6_hashtables.h>
b64c9256	28	#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
f6318e55	29	#endif
136cdc71	30
a31e1ffd LAT	31	#include <linux/netfilter/xt_socket.h>
a31e1ffd LAT	32
c0cd1156	33	#if IS_ENABLED(CONFIG_NF_CONNTRACK)
136cdc71 KK	34	#define XT_SOCKET_HAVE_CONNTRACK 1
	35	#include <net/netfilter/nf_conntrack.h>
	36	#endif
	37
d503b30b FW	38	static void
	39	xt_socket_put_sk(struct sock *sk)
	40	{
	41	if (sk->sk_state == TCP_TIME_WAIT)
	42	inet_twsk_put(inet_twsk(sk));
	43	else
	44	sock_put(sk);
	45	}
	46
136cdc71	47	static int
b64c9256	48	extract_icmp4_fields(const struct sk_buff *skb,
136cdc71 KK	49	u8 *protocol,
	50	__be32 *raddr,
	51	__be32 *laddr,
	52	__be16 *rport,
	53	__be16 *lport)
	54	{
	55	unsigned int outside_hdrlen = ip_hdrlen(skb);
	56	struct iphdr *inside_iph, _inside_iph;
	57	struct icmphdr *icmph, _icmph;
	58	__be16 *ports, _ports[2];
	59
	60	icmph = skb_header_pointer(skb, outside_hdrlen,
	61	sizeof(_icmph), &_icmph);
	62	if (icmph == NULL)
	63	return 1;
	64
	65	switch (icmph->type) {
	66	case ICMP_DEST_UNREACH:
	67	case ICMP_SOURCE_QUENCH:
	68	case ICMP_REDIRECT:
	69	case ICMP_TIME_EXCEEDED:
	70	case ICMP_PARAMETERPROB:
	71	break;
	72	default:
	73	return 1;
	74	}
	75
	76	inside_iph = skb_header_pointer(skb, outside_hdrlen +
	77	sizeof(struct icmphdr),
	78	sizeof(_inside_iph), &_inside_iph);
	79	if (inside_iph == NULL)
	80	return 1;
	81
	82	if (inside_iph->protocol != IPPROTO_TCP &&
	83	inside_iph->protocol != IPPROTO_UDP)
	84	return 1;
	85
	86	ports = skb_header_pointer(skb, outside_hdrlen +
	87	sizeof(struct icmphdr) +
	88	(inside_iph->ihl << 2),
	89	sizeof(_ports), &_ports);
	90	if (ports == NULL)
	91	return 1;
	92
	93	/* the inside IP packet is the one quoted from our side, thus
	94	* its saddr is the local address */
	95	*protocol = inside_iph->protocol;
	96	*laddr = inside_iph->saddr;
	97	*lport = ports[0];
	98	*raddr = inside_iph->daddr;
	99	*rport = ports[1];
	100
	101	return 0;
	102	}
	103
93742cf8 FW	104	/* "socket" match based redirection (no specific rule)
	105	* ===================================================
	106	*
	107	* There are connections with dynamic endpoints (e.g. FTP data
	108	* connection) that the user is unable to add explicit rules
	109	* for. These are taken care of by a generic "socket" rule. It is
	110	* assumed that the proxy application is trusted to open such
	111	* connections without explicit iptables rule (except of course the
	112	* generic 'socket' rule). In this case the following sockets are
	113	* matched in preference order:
	114	*
	115	* - match: if there's a fully established connection matching the
	116	* _packet_ tuple
	117	*
	118	* - match: if there's a non-zero bound listener (possibly with a
	119	* non-local address) We don't accept zero-bound listeners, since
	120	* then local services could intercept traffic going through the
	121	* box.
	122	*/
	123	static struct sock *
	124	xt_socket_get_sock_v4(struct net *net, const u8 protocol,
	125	const __be32 saddr, const __be32 daddr,
	126	const __be16 sport, const __be16 dport,
	127	const struct net_device *in)
	128	{
	129	switch (protocol) {
	130	case IPPROTO_TCP:
	131	return __inet_lookup(net, &tcp_hashinfo,
	132	saddr, sport, daddr, dport,
	133	in->ifindex);
	134	case IPPROTO_UDP:
	135	return udp4_lib_lookup(net, saddr, sport, daddr, dport,
	136	in->ifindex);
	137	}
	138	return NULL;
	139	}
	140
136cdc71	141	static bool
62fc8051	142	socket_match(const struct sk_buff skb, struct xt_action_param par,
a31e1ffd	143	const struct xt_socket_mtinfo1 *info)
136cdc71 KK	144	{
	145	const struct iphdr *iph = ip_hdr(skb);
	146	struct udphdr _hdr, *hp = NULL;
00028aa3	147	struct sock *sk = skb->sk;
6703aa74 PNA	148	__be32 uninitialized_var(daddr), uninitialized_var(saddr);
	149	__be16 uninitialized_var(dport), uninitialized_var(sport);
	150	u8 uninitialized_var(protocol);
136cdc71 KK	151	#ifdef XT_SOCKET_HAVE_CONNTRACK
	152	struct nf_conn const *ct;
	153	enum ip_conntrack_info ctinfo;
	154	#endif
	155
	156	if (iph->protocol == IPPROTO_UDP \|\| iph->protocol == IPPROTO_TCP) {
	157	hp = skb_header_pointer(skb, ip_hdrlen(skb),
	158	sizeof(_hdr), &_hdr);
	159	if (hp == NULL)
	160	return false;
	161
	162	protocol = iph->protocol;
	163	saddr = iph->saddr;
	164	sport = hp->source;
	165	daddr = iph->daddr;
	166	dport = hp->dest;
	167
	168	} else if (iph->protocol == IPPROTO_ICMP) {
b64c9256	169	if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr,
136cdc71 KK	170	&sport, &dport))
	171	return false;
	172	} else {
	173	return false;
	174	}
	175
	176	#ifdef XT_SOCKET_HAVE_CONNTRACK
	177	/* Do the lookup with the original socket address in case this is a
	178	* reply packet of an established SNAT-ted connection. */
	179
	180	ct = nf_ct_get(skb, &ctinfo);
5bfddbd4	181	if (ct && !nf_ct_is_untracked(ct) &&
136cdc71	182	((iph->protocol != IPPROTO_ICMP &&
fb048833	183	ctinfo == IP_CT_ESTABLISHED_REPLY) \|\|
136cdc71	184	(iph->protocol == IPPROTO_ICMP &&
fb048833	185	ctinfo == IP_CT_RELATED_REPLY)) &&
136cdc71 KK	186	(ct->status & IPS_SRC_NAT_DONE)) {
	187
	188	daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
	189	dport = (iph->protocol == IPPROTO_TCP) ?
	190	ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port :
	191	ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
	192	}
	193	#endif
	194
00028aa3	195	if (!sk)
93742cf8	196	sk = xt_socket_get_sock_v4(dev_net(skb->dev), protocol,
00028aa3	197	saddr, daddr, sport, dport,
93742cf8	198	par->in);
00028aa3	199	if (sk) {
a31e1ffd LAT	200	bool wildcard;
	201	bool transparent = true;
	202
681f130f ED	203	/* Ignore sockets listening on INADDR_ANY,
	204	* unless XT_SOCKET_NOWILDCARD is set
	205	*/
	206	wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
	207	sk->sk_state != TCP_TIME_WAIT &&
c720c7e8	208	inet_sk(sk)->inet_rcv_saddr == 0);
a31e1ffd LAT	209
	210	/* Ignore non-transparent sockets,
	211	if XT_SOCKET_TRANSPARENT is used */
baf60efa	212	if (info->flags & XT_SOCKET_TRANSPARENT)
a31e1ffd LAT	213	transparent = ((sk->sk_state != TCP_TIME_WAIT &&
	214	inet_sk(sk)->transparent) \|\|
	215	(sk->sk_state == TCP_TIME_WAIT &&
	216	inet_twsk(sk)->tw_transparent));
136cdc71	217
00028aa3 ED	218	if (sk != skb->sk)
00028aa3 ED	219	xt_socket_put_sk(sk);
a31e1ffd LAT	220
a31e1ffd LAT	221	if (wildcard \|\| !transparent)
136cdc71 KK	222	sk = NULL;
	223	}
	224
b64c9256 BS	225	pr_debug("proto %hhu %pI4:%hu -> %pI4:%hu (orig %pI4:%hu) sock %p\n",
	226	protocol, &saddr, ntohs(sport),
	227	&daddr, ntohs(dport),
	228	&iph->daddr, hp ? ntohs(hp->dest) : 0, sk);
136cdc71 KK	229
	230	return (sk != NULL);
	231	}
	232
a31e1ffd	233	static bool
b64c9256	234	socket_mt4_v0(const struct sk_buff skb, struct xt_action_param par)
a31e1ffd	235	{
baf60efa ED	236	static struct xt_socket_mtinfo1 xt_info_v0 = {
	237	.flags = 0,
	238	};
	239
	240	return socket_match(skb, par, &xt_info_v0);
a31e1ffd LAT	241	}
	242
	243	static bool
681f130f	244	socket_mt4_v1_v2(const struct sk_buff skb, struct xt_action_param par)
a31e1ffd LAT	245	{
	246	return socket_match(skb, par, par->matchinfo);
	247	}
	248
f6318e55	249	#ifdef XT_SOCKET_HAVE_IPV6
b64c9256 BS	250
	251	static int
	252	extract_icmp6_fields(const struct sk_buff *skb,
	253	unsigned int outside_hdrlen,
089282fb	254	int *protocol,
b64c9256 BS	255	struct in6_addr **raddr,
	256	struct in6_addr **laddr,
	257	__be16 *rport,
	258	__be16 *lport)
	259	{
	260	struct ipv6hdr *inside_iph, _inside_iph;
	261	struct icmp6hdr *icmph, _icmph;
	262	__be16 *ports, _ports[2];
	263	u8 inside_nexthdr;
75f2811c	264	__be16 inside_fragoff;
b64c9256 BS	265	int inside_hdrlen;
	266
	267	icmph = skb_header_pointer(skb, outside_hdrlen,
	268	sizeof(_icmph), &_icmph);
	269	if (icmph == NULL)
	270	return 1;
	271
	272	if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK)
	273	return 1;
	274
	275	inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph), sizeof(_inside_iph), &_inside_iph);
	276	if (inside_iph == NULL)
	277	return 1;
	278	inside_nexthdr = inside_iph->nexthdr;
	279
75f2811c JG	280	inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) + sizeof(_inside_iph),
75f2811c JG	281	&inside_nexthdr, &inside_fragoff);
b64c9256 BS	282	if (inside_hdrlen < 0)
	283	return 1; /* hjm: Packet has no/incomplete transport layer headers. */
	284
	285	if (inside_nexthdr != IPPROTO_TCP &&
	286	inside_nexthdr != IPPROTO_UDP)
	287	return 1;
	288
	289	ports = skb_header_pointer(skb, inside_hdrlen,
	290	sizeof(_ports), &_ports);
	291	if (ports == NULL)
	292	return 1;
	293
	294	/* the inside IP packet is the one quoted from our side, thus
	295	* its saddr is the local address */
	296	*protocol = inside_nexthdr;
	297	*laddr = &inside_iph->saddr;
	298	*lport = ports[0];
	299	*raddr = &inside_iph->daddr;
	300	*rport = ports[1];
	301
	302	return 0;
	303	}
	304
93742cf8 FW	305	static struct sock *
	306	xt_socket_get_sock_v6(struct net *net, const u8 protocol,
	307	const struct in6_addr saddr, const struct in6_addr daddr,
	308	const __be16 sport, const __be16 dport,
	309	const struct net_device *in)
	310	{
	311	switch (protocol) {
	312	case IPPROTO_TCP:
	313	return inet6_lookup(net, &tcp_hashinfo,
	314	saddr, sport, daddr, dport,
	315	in->ifindex);
	316	case IPPROTO_UDP:
	317	return udp6_lib_lookup(net, saddr, sport, daddr, dport,
	318	in->ifindex);
	319	}
	320
	321	return NULL;
	322	}
	323
b64c9256	324	static bool
681f130f	325	socket_mt6_v1_v2(const struct sk_buff skb, struct xt_action_param par)
b64c9256 BS	326	{
	327	struct ipv6hdr *iph = ipv6_hdr(skb);
	328	struct udphdr _hdr, *hp = NULL;
00028aa3	329	struct sock *sk = skb->sk;
6703aa74 PNA	330	struct in6_addr daddr = NULL, saddr = NULL;
	331	__be16 uninitialized_var(dport), uninitialized_var(sport);
	332	int thoff = 0, uninitialized_var(tproto);
b64c9256 BS	333	const struct xt_socket_mtinfo1 info = (struct xt_socket_mtinfo1 ) par->matchinfo;
b64c9256 BS	334
84018f55	335	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
b64c9256 BS	336	if (tproto < 0) {
	337	pr_debug("unable to find transport header in IPv6 packet, dropping\n");
	338	return NF_DROP;
	339	}
	340
	341	if (tproto == IPPROTO_UDP \|\| tproto == IPPROTO_TCP) {
	342	hp = skb_header_pointer(skb, thoff,
	343	sizeof(_hdr), &_hdr);
	344	if (hp == NULL)
	345	return false;
	346
	347	saddr = &iph->saddr;
	348	sport = hp->source;
	349	daddr = &iph->daddr;
	350	dport = hp->dest;
	351
	352	} else if (tproto == IPPROTO_ICMPV6) {
	353	if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr,
	354	&sport, &dport))
	355	return false;
	356	} else {
	357	return false;
	358	}
	359
00028aa3	360	if (!sk)
93742cf8	361	sk = xt_socket_get_sock_v6(dev_net(skb->dev), tproto,
00028aa3	362	saddr, daddr, sport, dport,
93742cf8	363	par->in);
00028aa3	364	if (sk) {
b64c9256 BS	365	bool wildcard;
	366	bool transparent = true;
	367
681f130f ED	368	/* Ignore sockets listening on INADDR_ANY
	369	* unless XT_SOCKET_NOWILDCARD is set
	370	*/
	371	wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
	372	sk->sk_state != TCP_TIME_WAIT &&
b64c9256 BS	373	ipv6_addr_any(&inet6_sk(sk)->rcv_saddr));
	374
	375	/* Ignore non-transparent sockets,
	376	if XT_SOCKET_TRANSPARENT is used */
baf60efa	377	if (info->flags & XT_SOCKET_TRANSPARENT)
b64c9256 BS	378	transparent = ((sk->sk_state != TCP_TIME_WAIT &&
	379	inet_sk(sk)->transparent) \|\|
	380	(sk->sk_state == TCP_TIME_WAIT &&
	381	inet_twsk(sk)->tw_transparent));
	382
00028aa3 ED	383	if (sk != skb->sk)
00028aa3 ED	384	xt_socket_put_sk(sk);
b64c9256 BS	385
	386	if (wildcard \|\| !transparent)
	387	sk = NULL;
	388	}
	389
089282fb	390	pr_debug("proto %hhd %pI6:%hu -> %pI6:%hu "
b64c9256 BS	391	"(orig %pI6:%hu) sock %p\n",
	392	tproto, saddr, ntohs(sport),
	393	daddr, ntohs(dport),
	394	&iph->daddr, hp ? ntohs(hp->dest) : 0, sk);
	395
	396	return (sk != NULL);
	397	}
	398	#endif
	399
681f130f ED	400	static int socket_mt_v1_check(const struct xt_mtchk_param *par)
	401	{
	402	const struct xt_socket_mtinfo1 info = (struct xt_socket_mtinfo1 ) par->matchinfo;
	403
	404	if (info->flags & ~XT_SOCKET_FLAGS_V1) {
	405	pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V1);
	406	return -EINVAL;
	407	}
	408	return 0;
	409	}
	410
	411	static int socket_mt_v2_check(const struct xt_mtchk_param *par)
	412	{
	413	const struct xt_socket_mtinfo2 info = (struct xt_socket_mtinfo2 ) par->matchinfo;
	414
	415	if (info->flags & ~XT_SOCKET_FLAGS_V2) {
	416	pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V2);
	417	return -EINVAL;
	418	}
	419	return 0;
	420	}
	421
a31e1ffd LAT	422	static struct xt_match socket_mt_reg[] __read_mostly = {
	423	{
	424	.name = "socket",
	425	.revision = 0,
	426	.family = NFPROTO_IPV4,
b64c9256	427	.match = socket_mt4_v0,
aa3c487f JE	428	.hooks = (1 << NF_INET_PRE_ROUTING) \|
aa3c487f JE	429	(1 << NF_INET_LOCAL_IN),
a31e1ffd LAT	430	.me = THIS_MODULE,
	431	},
	432	{
	433	.name = "socket",
	434	.revision = 1,
	435	.family = NFPROTO_IPV4,
681f130f ED	436	.match = socket_mt4_v1_v2,
681f130f ED	437	.checkentry = socket_mt_v1_check,
a31e1ffd	438	.matchsize = sizeof(struct xt_socket_mtinfo1),
aa3c487f JE	439	.hooks = (1 << NF_INET_PRE_ROUTING) \|
aa3c487f JE	440	(1 << NF_INET_LOCAL_IN),
a31e1ffd LAT	441	.me = THIS_MODULE,
a31e1ffd LAT	442	},
f6318e55	443	#ifdef XT_SOCKET_HAVE_IPV6
b64c9256 BS	444	{
	445	.name = "socket",
	446	.revision = 1,
	447	.family = NFPROTO_IPV6,
681f130f ED	448	.match = socket_mt6_v1_v2,
	449	.checkentry = socket_mt_v1_check,
	450	.matchsize = sizeof(struct xt_socket_mtinfo1),
	451	.hooks = (1 << NF_INET_PRE_ROUTING) \|
	452	(1 << NF_INET_LOCAL_IN),
	453	.me = THIS_MODULE,
	454	},
	455	#endif
	456	{
	457	.name = "socket",
	458	.revision = 2,
	459	.family = NFPROTO_IPV4,
	460	.match = socket_mt4_v1_v2,
	461	.checkentry = socket_mt_v2_check,
	462	.matchsize = sizeof(struct xt_socket_mtinfo1),
	463	.hooks = (1 << NF_INET_PRE_ROUTING) \|
	464	(1 << NF_INET_LOCAL_IN),
	465	.me = THIS_MODULE,
	466	},
	467	#ifdef XT_SOCKET_HAVE_IPV6
	468	{
	469	.name = "socket",
	470	.revision = 2,
	471	.family = NFPROTO_IPV6,
	472	.match = socket_mt6_v1_v2,
	473	.checkentry = socket_mt_v2_check,
b64c9256 BS	474	.matchsize = sizeof(struct xt_socket_mtinfo1),
	475	.hooks = (1 << NF_INET_PRE_ROUTING) \|
	476	(1 << NF_INET_LOCAL_IN),
	477	.me = THIS_MODULE,
	478	},
	479	#endif
136cdc71 KK	480	};
	481
	482	static int __init socket_mt_init(void)
	483	{
	484	nf_defrag_ipv4_enable();
f6318e55	485	#ifdef XT_SOCKET_HAVE_IPV6
b64c9256 BS	486	nf_defrag_ipv6_enable();
	487	#endif
	488
a31e1ffd	489	return xt_register_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
136cdc71 KK	490	}
	491
	492	static void __exit socket_mt_exit(void)
	493	{
a31e1ffd	494	xt_unregister_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
136cdc71 KK	495	}
	496
	497	module_init(socket_mt_init);
	498	module_exit(socket_mt_exit);
	499
	500	MODULE_LICENSE("GPL");
	501	MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler");
	502	MODULE_DESCRIPTION("x_tables socket match module");
	503	MODULE_ALIAS("ipt_socket");
b64c9256	504	MODULE_ALIAS("ip6t_socket");