tproxy: added IPv6 support to the socket match

The ICMP extraction bits were contributed by Harry Mason.

Signed-off-by: Balazs Scheidler <bazsi@balabit.hu>
Signed-off-by: KOVACS Krisztian <hidden@balabit.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>

1 files changed, 154 insertions, 11 deletions

diff --git a/net/netfilter/xt_socket.c b/net/netfilter/xt_socket.c
index 266faa0a2fbf..2dbd4c857735 100644
--- a/net/netfilter/xt_socket.c
+++ b/net/netfilter/xt_socket.c
@@ -14,6 +14,7 @@
 #include <linux/skbuff.h>
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter_ipv6/ip6_tables.h>
 #include <net/tcp.h>
 #include <net/udp.h>
 #include <net/icmp.h>
@@ -21,6 +22,7 @@
 #include <net/inet_sock.h>
 #include <net/netfilter/nf_tproxy_core.h>
 #include <net/netfilter/ipv4/nf_defrag_ipv4.h>
+#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
 
 #include <linux/netfilter/xt_socket.h>
 
@@ -30,7 +32,7 @@
 #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,
@@ -86,7 +88,6 @@ extract_icmp_fields(const struct sk_buff *skb,
         return 0;
 }
 
-
 static bool
 socket_match(const struct sk_buff *skb, struct xt_action_param *par,
              const struct xt_socket_mtinfo1 *info)
@@ -115,7 +116,7 @@ socket_match(const struct sk_buff *skb, struct xt_action_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 {
@@ -165,32 +166,157 @@ socket_match(const struct sk_buff *skb, struct xt_action_param *par,
                         sk = NULL;
         }
 
-        pr_debug("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, struct xt_action_param *par)
+socket_mt4_v0(const struct sk_buff *skb, struct xt_action_param *par)
 {
         return socket_match(skb, par, NULL);
 }
 
 static bool
-socket_mt_v1(const struct sk_buff *skb, struct xt_action_param *par)
+socket_mt4_v1(const struct sk_buff *skb, struct xt_action_param *par)
 {
         return socket_match(skb, par, par->matchinfo);
 }
 
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+
+static int
+extract_icmp6_fields(const struct sk_buff *skb,
+                     unsigned int outside_hdrlen,
+                     u8 *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;
+        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);
+        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 bool
+socket_mt6_v1(const struct sk_buff *skb, struct xt_action_param *par)
+{
+        struct ipv6hdr *iph = ipv6_hdr(skb);
+        struct udphdr _hdr, *hp = NULL;
+        struct sock *sk;
+        struct in6_addr *daddr, *saddr;
+        __be16 dport, sport;
+        int thoff;
+        u8 tproto;
+        const struct xt_socket_mtinfo1 *info = (struct xt_socket_mtinfo1 *) par->matchinfo;
+
+        tproto = ipv6_find_hdr(skb, &thoff, -1, 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;
+        }
+
+        sk = nf_tproxy_get_sock_v6(dev_net(skb->dev), tproto,
+                                   saddr, daddr, sport, dport, par->in, NFT_LOOKUP_ANY);
+        if (sk != NULL) {
+                bool wildcard;
+                bool transparent = true;
+
+                /* Ignore sockets listening on INADDR_ANY */
+                wildcard = (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 && 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 (wildcard || !transparent)
+                        sk = NULL;
+        }
+
+        pr_debug("proto %hhu %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 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,
@@ -199,17 +325,33 @@ static struct xt_match socket_mt_reg[] __read_mostly = {
                 .name           = "socket",
                 .revision       = 1,
                 .family         = NFPROTO_IPV4,
-                .match          = socket_mt_v1,
+                .match          = socket_mt4_v1,
                 .matchsize      = sizeof(struct xt_socket_mtinfo1),
                 .hooks          = (1 << NF_INET_PRE_ROUTING) |
                                   (1 << NF_INET_LOCAL_IN),
                 .me             = THIS_MODULE,
         },
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+        {
+                .name           = "socket",
+                .revision       = 1,
+                .family         = NFPROTO_IPV6,
+                .match          = socket_mt6_v1,
+                .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();
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+        nf_defrag_ipv6_enable();
+#endif
+
         return xt_register_matches(socket_mt_reg, ARRAY_SIZE(socket_mt_reg));
 }
 
@@ -225,3 +367,4 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Krisztian Kovacs, Balazs Scheidler");
 MODULE_DESCRIPTION("x_tables socket match module");
 MODULE_ALIAS("ipt_socket");
+MODULE_ALIAS("ip6t_socket");