1 files changed, 297 insertions, 30 deletions

diff --git a/net/netfilter/xt_socket.c b/net/netfilter/xt_socket.c
index 6a902564d24..1ba67931eb1 100644
--- a/net/netfilter/xt_socket.c
+++ b/net/netfilter/xt_socket.c
@@ -9,7 +9,7 @@
  * 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>
@@ -19,18 +19,24 @@
 #include <net/icmp.h>
 #include <net/sock.h>
 #include <net/inet_sock.h>
-#include <net/netfilter/nf_tproxy_core.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 defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
+#if IS_ENABLED(CONFIG_NF_CONNTRACK)
 #define XT_SOCKET_HAVE_CONNTRACK 1
 #include <net/netfilter/nf_conntrack.h>
 #endif
 
 static int
-extract_icmp_fields(const struct sk_buff *skb,
+extract_icmp4_fields(const struct sk_buff *skb,
 		    u8 *protocol,
 		    __be32 *raddr,
 		    __be32 *laddr,
@@ -86,17 +92,53 @@ extract_icmp_fields(const struct sk_buff *skb,
 	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, const struct xt_match_param *par,
+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;
-	__be32 daddr, saddr;
-	__be16 dport, sport;
-	u8 protocol;
+	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;
@@ -115,7 +157,7 @@ socket_match(const struct sk_buff *skb, const struct xt_match_param *par,
 		dport = hp->dest;
 
 	} else if (iph->protocol == IPPROTO_ICMP) {
-		if (extract_icmp_fields(skb, &protocol, &saddr, &daddr,
+		if (extract_icmp4_fields(skb, &protocol, &saddr, &daddr,
 					&sport, &dport))
 			return false;
 	} else {
@@ -127,11 +169,11 @@ socket_match(const struct sk_buff *skb, const struct xt_match_param *par,
 	 * reply packet of an established SNAT-ted connection. */
 
 	ct = nf_ct_get(skb, &ctinfo);
-	if (ct && (ct != &nf_conntrack_untracked) &&
+	if (ct && !nf_ct_is_untracked(ct) &&
 	    ((iph->protocol != IPPROTO_ICMP &&
-	      ctinfo == IP_CT_IS_REPLY + IP_CT_ESTABLISHED) ||
+	      ctinfo == IP_CT_ESTABLISHED_REPLY) ||
 	     (iph->protocol == IPPROTO_ICMP &&
-	      ctinfo == IP_CT_IS_REPLY + IP_CT_RELATED)) &&
+	      ctinfo == IP_CT_RELATED_REPLY)) &&
 	    (ct->status & IPS_SRC_NAT_DONE)) {
 
 		daddr = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
@@ -141,57 +183,239 @@ socket_match(const struct sk_buff *skb, const struct xt_match_param *par,
 	}
 #endif
 
-	sk = nf_tproxy_get_sock_v4(dev_net(skb->dev), protocol,
-				   saddr, daddr, sport, dport, par->in, false);
-	if (sk != NULL) {
+	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 */
-		wildcard = (sk->sk_state != TCP_TIME_WAIT &&
+		/* 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 && info->flags & XT_SOCKET_TRANSPARENT)
+		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));
 
-		nf_tproxy_put_sock(sk);
+		if (sk != skb->sk)
+			sock_gen_put(sk);
 
 		if (wildcard || !transparent)
 			sk = NULL;
 	}
 
-	pr_debug("socket match: proto %u %08x:%u -> %08x:%u "
-		 "(orig %08x:%u) sock %p\n",
-		 protocol, ntohl(saddr), ntohs(sport),
-		 ntohl(daddr), ntohs(dport),
-		 ntohl(iph->daddr), hp ? ntohs(hp->dest) : 0, sk);
+	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_mt_v0(const struct sk_buff *skb, const struct xt_match_param *par)
+socket_mt4_v0(const struct sk_buff *skb, struct xt_action_param *par)
 {
-	return socket_match(skb, par, NULL);
+	static struct xt_socket_mtinfo1 xt_info_v0 = {
+		.flags = 0,
+	};
+
+	return socket_match(skb, par, &xt_info_v0);
 }
 
 static bool
-socket_mt_v1(const struct sk_buff *skb, const struct xt_match_param *par)
+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_mt_v0,
+		.match		= socket_mt4_v0,
 		.hooks		= (1 << NF_INET_PRE_ROUTING) |
 				  (1 << NF_INET_LOCAL_IN),
 		.me		= THIS_MODULE,
@@ -200,17 +424,59 @@ static struct xt_match socket_mt_reg[] __read_mostly = {
 		.name		= "socket",
 		.revision	= 1,
 		.family		= NFPROTO_IPV4,
-		.match		= socket_mt_v1,
+		.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));
 }
 
@@ -226,3 +492,4 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler");
 MODULE_DESCRIPTION("x_tables socket match module");
 MODULE_ALIAS("ipt_socket");
+MODULE_ALIAS("ip6t_socket");