[linux-2.6-block.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 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)
			sock_gen_put(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(&sk->sk_v6_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)
			sock_gen_put(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
	38	static int
b64c9256	39	extract_icmp4_fields(const struct sk_buff *skb,
136cdc71 KK	40	u8 *protocol,
	41	__be32 *raddr,
	42	__be32 *laddr,
	43	__be16 *rport,
	44	__be16 *lport)
	45	{
	46	unsigned int outside_hdrlen = ip_hdrlen(skb);
	47	struct iphdr *inside_iph, _inside_iph;
	48	struct icmphdr *icmph, _icmph;
	49	__be16 *ports, _ports[2];
	50
	51	icmph = skb_header_pointer(skb, outside_hdrlen,
	52	sizeof(_icmph), &_icmph);
	53	if (icmph == NULL)
	54	return 1;
	55
	56	switch (icmph->type) {
	57	case ICMP_DEST_UNREACH:
	58	case ICMP_SOURCE_QUENCH:
	59	case ICMP_REDIRECT:
	60	case ICMP_TIME_EXCEEDED:
	61	case ICMP_PARAMETERPROB:
	62	break;
	63	default:
	64	return 1;
	65	}
	66
	67	inside_iph = skb_header_pointer(skb, outside_hdrlen +
	68	sizeof(struct icmphdr),
	69	sizeof(_inside_iph), &_inside_iph);
	70	if (inside_iph == NULL)
	71	return 1;
	72
	73	if (inside_iph->protocol != IPPROTO_TCP &&
	74	inside_iph->protocol != IPPROTO_UDP)
	75	return 1;
	76
	77	ports = skb_header_pointer(skb, outside_hdrlen +
	78	sizeof(struct icmphdr) +
	79	(inside_iph->ihl << 2),
	80	sizeof(_ports), &_ports);
	81	if (ports == NULL)
	82	return 1;
	83
	84	/* the inside IP packet is the one quoted from our side, thus
	85	* its saddr is the local address */
	86	*protocol = inside_iph->protocol;
	87	*laddr = inside_iph->saddr;
	88	*lport = ports[0];
	89	*raddr = inside_iph->daddr;
	90	*rport = ports[1];
	91
	92	return 0;
	93	}
	94
93742cf8 FW	95	/* "socket" match based redirection (no specific rule)
	96	* ===================================================
	97	*
	98	* There are connections with dynamic endpoints (e.g. FTP data
	99	* connection) that the user is unable to add explicit rules
	100	* for. These are taken care of by a generic "socket" rule. It is
	101	* assumed that the proxy application is trusted to open such
	102	* connections without explicit iptables rule (except of course the
	103	* generic 'socket' rule). In this case the following sockets are
	104	* matched in preference order:
	105	*
	106	* - match: if there's a fully established connection matching the
	107	* _packet_ tuple
	108	*
	109	* - match: if there's a non-zero bound listener (possibly with a
	110	* non-local address) We don't accept zero-bound listeners, since
	111	* then local services could intercept traffic going through the
	112	* box.
	113	*/
	114	static struct sock *
	115	xt_socket_get_sock_v4(struct net *net, const u8 protocol,
	116	const __be32 saddr, const __be32 daddr,
	117	const __be16 sport, const __be16 dport,
	118	const struct net_device *in)
	119	{
	120	switch (protocol) {
	121	case IPPROTO_TCP:
	122	return __inet_lookup(net, &tcp_hashinfo,
	123	saddr, sport, daddr, dport,
	124	in->ifindex);
	125	case IPPROTO_UDP:
	126	return udp4_lib_lookup(net, saddr, sport, daddr, dport,
	127	in->ifindex);
	128	}
	129	return NULL;
	130	}
	131
136cdc71	132	static bool
62fc8051	133	socket_match(const struct sk_buff skb, struct xt_action_param par,
a31e1ffd	134	const struct xt_socket_mtinfo1 *info)
136cdc71 KK	135	{
	136	const struct iphdr *iph = ip_hdr(skb);
	137	struct udphdr _hdr, *hp = NULL;
00028aa3	138	struct sock *sk = skb->sk;
6703aa74 PNA	139	__be32 uninitialized_var(daddr), uninitialized_var(saddr);
	140	__be16 uninitialized_var(dport), uninitialized_var(sport);
	141	u8 uninitialized_var(protocol);
136cdc71 KK	142	#ifdef XT_SOCKET_HAVE_CONNTRACK
	143	struct nf_conn const *ct;
	144	enum ip_conntrack_info ctinfo;
	145	#endif
	146
	147	if (iph->protocol == IPPROTO_UDP \|\| iph->protocol == IPPROTO_TCP) {
	148	hp = skb_header_pointer(skb, ip_hdrlen(skb),
	149	sizeof(_hdr), &_hdr);
	150	if (hp == NULL)
	151	return false;
	152
	153	protocol = iph->protocol;
	154	saddr = iph->saddr;
	155	sport = hp->source;
	156	daddr = iph->daddr;
	157	dport = hp->dest;
	158
	159	} else if (iph->protocol == IPPROTO_ICMP) {
b64c9256	160	if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr,
136cdc71 KK	161	&sport, &dport))
	162	return false;
	163	} else {
	164	return false;
	165	}
	166
	167	#ifdef XT_SOCKET_HAVE_CONNTRACK
	168	/* Do the lookup with the original socket address in case this is a
	169	* reply packet of an established SNAT-ted connection. */
	170
	171	ct = nf_ct_get(skb, &ctinfo);
5bfddbd4	172	if (ct && !nf_ct_is_untracked(ct) &&
136cdc71	173	((iph->protocol != IPPROTO_ICMP &&
fb048833	174	ctinfo == IP_CT_ESTABLISHED_REPLY) \|\|
136cdc71	175	(iph->protocol == IPPROTO_ICMP &&
fb048833	176	ctinfo == IP_CT_RELATED_REPLY)) &&
136cdc71 KK	177	(ct->status & IPS_SRC_NAT_DONE)) {
	178
	179	daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
	180	dport = (iph->protocol == IPPROTO_TCP) ?
	181	ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.tcp.port :
	182	ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port;
	183	}
	184	#endif
	185
00028aa3	186	if (!sk)
93742cf8	187	sk = xt_socket_get_sock_v4(dev_net(skb->dev), protocol,
00028aa3	188	saddr, daddr, sport, dport,
93742cf8	189	par->in);
00028aa3	190	if (sk) {
a31e1ffd LAT	191	bool wildcard;
	192	bool transparent = true;
	193
681f130f ED	194	/* Ignore sockets listening on INADDR_ANY,
	195	* unless XT_SOCKET_NOWILDCARD is set
	196	*/
	197	wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
	198	sk->sk_state != TCP_TIME_WAIT &&
c720c7e8	199	inet_sk(sk)->inet_rcv_saddr == 0);
a31e1ffd LAT	200
	201	/* Ignore non-transparent sockets,
	202	if XT_SOCKET_TRANSPARENT is used */
baf60efa	203	if (info->flags & XT_SOCKET_TRANSPARENT)
a31e1ffd LAT	204	transparent = ((sk->sk_state != TCP_TIME_WAIT &&
	205	inet_sk(sk)->transparent) \|\|
	206	(sk->sk_state == TCP_TIME_WAIT &&
	207	inet_twsk(sk)->tw_transparent));
136cdc71	208
00028aa3	209	if (sk != skb->sk)
1a8bf6ee	210	sock_gen_put(sk);
a31e1ffd LAT	211
a31e1ffd LAT	212	if (wildcard \|\| !transparent)
136cdc71 KK	213	sk = NULL;
	214	}
	215
b64c9256 BS	216	pr_debug("proto %hhu %pI4:%hu -> %pI4:%hu (orig %pI4:%hu) sock %p\n",
	217	protocol, &saddr, ntohs(sport),
	218	&daddr, ntohs(dport),
	219	&iph->daddr, hp ? ntohs(hp->dest) : 0, sk);
136cdc71 KK	220
	221	return (sk != NULL);
	222	}
	223
a31e1ffd	224	static bool
b64c9256	225	socket_mt4_v0(const struct sk_buff skb, struct xt_action_param par)
a31e1ffd	226	{
baf60efa ED	227	static struct xt_socket_mtinfo1 xt_info_v0 = {
	228	.flags = 0,
	229	};
	230
	231	return socket_match(skb, par, &xt_info_v0);
a31e1ffd LAT	232	}
	233
	234	static bool
681f130f	235	socket_mt4_v1_v2(const struct sk_buff skb, struct xt_action_param par)
a31e1ffd LAT	236	{
	237	return socket_match(skb, par, par->matchinfo);
	238	}
	239
f6318e55	240	#ifdef XT_SOCKET_HAVE_IPV6
b64c9256 BS	241
	242	static int
	243	extract_icmp6_fields(const struct sk_buff *skb,
	244	unsigned int outside_hdrlen,
089282fb	245	int *protocol,
b64c9256 BS	246	struct in6_addr **raddr,
	247	struct in6_addr **laddr,
	248	__be16 *rport,
	249	__be16 *lport)
	250	{
	251	struct ipv6hdr *inside_iph, _inside_iph;
	252	struct icmp6hdr *icmph, _icmph;
	253	__be16 *ports, _ports[2];
	254	u8 inside_nexthdr;
75f2811c	255	__be16 inside_fragoff;
b64c9256 BS	256	int inside_hdrlen;
	257
	258	icmph = skb_header_pointer(skb, outside_hdrlen,
	259	sizeof(_icmph), &_icmph);
	260	if (icmph == NULL)
	261	return 1;
	262
	263	if (icmph->icmp6_type & ICMPV6_INFOMSG_MASK)
	264	return 1;
	265
	266	inside_iph = skb_header_pointer(skb, outside_hdrlen + sizeof(_icmph), sizeof(_inside_iph), &_inside_iph);
	267	if (inside_iph == NULL)
	268	return 1;
	269	inside_nexthdr = inside_iph->nexthdr;
	270
75f2811c JG	271	inside_hdrlen = ipv6_skip_exthdr(skb, outside_hdrlen + sizeof(_icmph) + sizeof(_inside_iph),
75f2811c JG	272	&inside_nexthdr, &inside_fragoff);
b64c9256 BS	273	if (inside_hdrlen < 0)
	274	return 1; /* hjm: Packet has no/incomplete transport layer headers. */
	275
	276	if (inside_nexthdr != IPPROTO_TCP &&
	277	inside_nexthdr != IPPROTO_UDP)
	278	return 1;
	279
	280	ports = skb_header_pointer(skb, inside_hdrlen,
	281	sizeof(_ports), &_ports);
	282	if (ports == NULL)
	283	return 1;
	284
	285	/* the inside IP packet is the one quoted from our side, thus
	286	* its saddr is the local address */
	287	*protocol = inside_nexthdr;
	288	*laddr = &inside_iph->saddr;
	289	*lport = ports[0];
	290	*raddr = &inside_iph->daddr;
	291	*rport = ports[1];
	292
	293	return 0;
	294	}
	295
93742cf8 FW	296	static struct sock *
	297	xt_socket_get_sock_v6(struct net *net, const u8 protocol,
	298	const struct in6_addr saddr, const struct in6_addr daddr,
	299	const __be16 sport, const __be16 dport,
	300	const struct net_device *in)
	301	{
	302	switch (protocol) {
	303	case IPPROTO_TCP:
	304	return inet6_lookup(net, &tcp_hashinfo,
	305	saddr, sport, daddr, dport,
	306	in->ifindex);
	307	case IPPROTO_UDP:
	308	return udp6_lib_lookup(net, saddr, sport, daddr, dport,
	309	in->ifindex);
	310	}
	311
	312	return NULL;
	313	}
	314
b64c9256	315	static bool
681f130f	316	socket_mt6_v1_v2(const struct sk_buff skb, struct xt_action_param par)
b64c9256 BS	317	{
	318	struct ipv6hdr *iph = ipv6_hdr(skb);
	319	struct udphdr _hdr, *hp = NULL;
00028aa3	320	struct sock *sk = skb->sk;
6703aa74 PNA	321	struct in6_addr daddr = NULL, saddr = NULL;
	322	__be16 uninitialized_var(dport), uninitialized_var(sport);
	323	int thoff = 0, uninitialized_var(tproto);
b64c9256 BS	324	const struct xt_socket_mtinfo1 info = (struct xt_socket_mtinfo1 ) par->matchinfo;
b64c9256 BS	325
84018f55	326	tproto = ipv6_find_hdr(skb, &thoff, -1, NULL, NULL);
b64c9256 BS	327	if (tproto < 0) {
	328	pr_debug("unable to find transport header in IPv6 packet, dropping\n");
	329	return NF_DROP;
	330	}
	331
	332	if (tproto == IPPROTO_UDP \|\| tproto == IPPROTO_TCP) {
	333	hp = skb_header_pointer(skb, thoff,
	334	sizeof(_hdr), &_hdr);
	335	if (hp == NULL)
	336	return false;
	337
	338	saddr = &iph->saddr;
	339	sport = hp->source;
	340	daddr = &iph->daddr;
	341	dport = hp->dest;
	342
	343	} else if (tproto == IPPROTO_ICMPV6) {
	344	if (extract_icmp6_fields(skb, thoff, &tproto, &saddr, &daddr,
	345	&sport, &dport))
	346	return false;
	347	} else {
	348	return false;
	349	}
	350
00028aa3	351	if (!sk)
93742cf8	352	sk = xt_socket_get_sock_v6(dev_net(skb->dev), tproto,
00028aa3	353	saddr, daddr, sport, dport,
93742cf8	354	par->in);
00028aa3	355	if (sk) {
b64c9256 BS	356	bool wildcard;
	357	bool transparent = true;
	358
681f130f ED	359	/* Ignore sockets listening on INADDR_ANY
	360	* unless XT_SOCKET_NOWILDCARD is set
	361	*/
	362	wildcard = (!(info->flags & XT_SOCKET_NOWILDCARD) &&
	363	sk->sk_state != TCP_TIME_WAIT &&
efe4208f	364	ipv6_addr_any(&sk->sk_v6_rcv_saddr));
b64c9256 BS	365
	366	/* Ignore non-transparent sockets,
	367	if XT_SOCKET_TRANSPARENT is used */
baf60efa	368	if (info->flags & XT_SOCKET_TRANSPARENT)
b64c9256 BS	369	transparent = ((sk->sk_state != TCP_TIME_WAIT &&
	370	inet_sk(sk)->transparent) \|\|
	371	(sk->sk_state == TCP_TIME_WAIT &&
	372	inet_twsk(sk)->tw_transparent));
	373
00028aa3	374	if (sk != skb->sk)
1a8bf6ee	375	sock_gen_put(sk);
b64c9256 BS	376
	377	if (wildcard \|\| !transparent)
	378	sk = NULL;
	379	}
	380
089282fb	381	pr_debug("proto %hhd %pI6:%hu -> %pI6:%hu "
b64c9256 BS	382	"(orig %pI6:%hu) sock %p\n",
	383	tproto, saddr, ntohs(sport),
	384	daddr, ntohs(dport),
	385	&iph->daddr, hp ? ntohs(hp->dest) : 0, sk);
	386
	387	return (sk != NULL);
	388	}
	389	#endif
	390
681f130f ED	391	static int socket_mt_v1_check(const struct xt_mtchk_param *par)
	392	{
	393	const struct xt_socket_mtinfo1 info = (struct xt_socket_mtinfo1 ) par->matchinfo;
	394
	395	if (info->flags & ~XT_SOCKET_FLAGS_V1) {
	396	pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V1);
	397	return -EINVAL;
	398	}
	399	return 0;
	400	}
	401
	402	static int socket_mt_v2_check(const struct xt_mtchk_param *par)
	403	{
	404	const struct xt_socket_mtinfo2 info = (struct xt_socket_mtinfo2 ) par->matchinfo;
	405
	406	if (info->flags & ~XT_SOCKET_FLAGS_V2) {
	407	pr_info("unknown flags 0x%x\n", info->flags & ~XT_SOCKET_FLAGS_V2);
	408	return -EINVAL;
	409	}
	410	return 0;
	411	}
	412
a31e1ffd LAT	413	static struct xt_match socket_mt_reg[] __read_mostly = {
	414	{
	415	.name = "socket",
	416	.revision = 0,
	417	.family = NFPROTO_IPV4,
b64c9256	418	.match = socket_mt4_v0,
aa3c487f JE	419	.hooks = (1 << NF_INET_PRE_ROUTING) \|
aa3c487f JE	420	(1 << NF_INET_LOCAL_IN),
a31e1ffd LAT	421	.me = THIS_MODULE,
	422	},
	423	{
	424	.name = "socket",
	425	.revision = 1,
	426	.family = NFPROTO_IPV4,
681f130f ED	427	.match = socket_mt4_v1_v2,
681f130f ED	428	.checkentry = socket_mt_v1_check,
a31e1ffd	429	.matchsize = sizeof(struct xt_socket_mtinfo1),
aa3c487f JE	430	.hooks = (1 << NF_INET_PRE_ROUTING) \|
aa3c487f JE	431	(1 << NF_INET_LOCAL_IN),
a31e1ffd LAT	432	.me = THIS_MODULE,
a31e1ffd LAT	433	},
f6318e55	434	#ifdef XT_SOCKET_HAVE_IPV6
b64c9256 BS	435	{
	436	.name = "socket",
	437	.revision = 1,
	438	.family = NFPROTO_IPV6,
681f130f ED	439	.match = socket_mt6_v1_v2,
	440	.checkentry = socket_mt_v1_check,
	441	.matchsize = sizeof(struct xt_socket_mtinfo1),
	442	.hooks = (1 << NF_INET_PRE_ROUTING) \|
	443	(1 << NF_INET_LOCAL_IN),
	444	.me = THIS_MODULE,
	445	},
	446	#endif
	447	{
	448	.name = "socket",
	449	.revision = 2,
	450	.family = NFPROTO_IPV4,
	451	.match = socket_mt4_v1_v2,
	452	.checkentry = socket_mt_v2_check,
	453	.matchsize = sizeof(struct xt_socket_mtinfo1),
	454	.hooks = (1 << NF_INET_PRE_ROUTING) \|
	455	(1 << NF_INET_LOCAL_IN),
	456	.me = THIS_MODULE,
	457	},
	458	#ifdef XT_SOCKET_HAVE_IPV6
	459	{
	460	.name = "socket",
	461	.revision = 2,
	462	.family = NFPROTO_IPV6,
	463	.match = socket_mt6_v1_v2,
	464	.checkentry = socket_mt_v2_check,
b64c9256 BS	465	.matchsize = sizeof(struct xt_socket_mtinfo1),
	466	.hooks = (1 << NF_INET_PRE_ROUTING) \|
	467	(1 << NF_INET_LOCAL_IN),
	468	.me = THIS_MODULE,
	469	},
	470	#endif
136cdc71 KK	471	};
	472
	473	static int __init socket_mt_init(void)
	474	{
	475	nf_defrag_ipv4_enable();
f6318e55	476	#ifdef XT_SOCKET_HAVE_IPV6
b64c9256 BS	477	nf_defrag_ipv6_enable();
	478	#endif
	479
a31e1ffd	480	return xt_register_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
136cdc71 KK	481	}
	482
	483	static void __exit socket_mt_exit(void)
	484	{
a31e1ffd	485	xt_unregister_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
136cdc71 KK	486	}
	487
	488	module_init(socket_mt_init);
	489	module_exit(socket_mt_exit);
	490
	491	MODULE_LICENSE("GPL");
	492	MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler");
	493	MODULE_DESCRIPTION("x_tables socket match module");
	494	MODULE_ALIAS("ipt_socket");
b64c9256	495	MODULE_ALIAS("ip6t_socket");