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Diffstat (limited to 'net/netfilter/xt_TPROXY.c')
-rw-r--r--net/netfilter/xt_TPROXY.c201
1 files changed, 193 insertions, 8 deletions
diff --git a/net/netfilter/xt_TPROXY.c b/net/netfilter/xt_TPROXY.c
index 640678f47a2..ef8a926752a 100644
--- a/net/netfilter/xt_TPROXY.c
+++ b/net/netfilter/xt_TPROXY.c
@@ -15,24 +15,45 @@
#include <linux/ip.h>
#include <net/checksum.h>
#include <net/udp.h>
+#include <net/tcp.h>
#include <net/inet_sock.h>
+#include <net/inet_hashtables.h>
#include <linux/inetdevice.h>
#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv4/ip_tables.h>
#include <net/netfilter/ipv4/nf_defrag_ipv4.h>
-#if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
+#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
#define XT_TPROXY_HAVE_IPV6 1
#include <net/if_inet6.h>
#include <net/addrconf.h>
+#include <net/inet6_hashtables.h>
#include <linux/netfilter_ipv6/ip6_tables.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#endif
-#include <net/netfilter/nf_tproxy_core.h>
#include <linux/netfilter/xt_TPROXY.h>
+enum nf_tproxy_lookup_t {
+ NFT_LOOKUP_LISTENER,
+ NFT_LOOKUP_ESTABLISHED,
+};
+
+static bool tproxy_sk_is_transparent(struct sock *sk)
+{
+ if (sk->sk_state != TCP_TIME_WAIT) {
+ if (inet_sk(sk)->transparent)
+ return true;
+ sock_put(sk);
+ } else {
+ if (inet_twsk(sk)->tw_transparent)
+ return true;
+ inet_twsk_put(inet_twsk(sk));
+ }
+ return false;
+}
+
static inline __be32
tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
{
@@ -54,8 +75,159 @@ tproxy_laddr4(struct sk_buff *skb, __be32 user_laddr, __be32 daddr)
return laddr ? laddr : daddr;
}
+/*
+ * This is used when the user wants to intercept a connection matching
+ * an explicit iptables rule. In this case the sockets are assumed
+ * matching in preference order:
+ *
+ * - match: if there's a fully established connection matching the
+ * _packet_ tuple, it is returned, assuming the redirection
+ * already took place and we process a packet belonging to an
+ * established connection
+ *
+ * - match: if there's a listening socket matching the redirection
+ * (e.g. on-port & on-ip of the connection), it is returned,
+ * regardless if it was bound to 0.0.0.0 or an explicit
+ * address. The reasoning is that if there's an explicit rule, it
+ * does not really matter if the listener is bound to an interface
+ * or to 0. The user already stated that he wants redirection
+ * (since he added the rule).
+ *
+ * Please note that there's an overlap between what a TPROXY target
+ * and a socket match will match. Normally if you have both rules the
+ * "socket" match will be the first one, effectively all packets
+ * belonging to established connections going through that one.
+ */
+static inline struct sock *
+nf_tproxy_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,
+ const enum nf_tproxy_lookup_t lookup_type)
+{
+ struct sock *sk;
+
+ switch (protocol) {
+ case IPPROTO_TCP:
+ switch (lookup_type) {
+ case NFT_LOOKUP_LISTENER:
+ sk = inet_lookup_listener(net, &tcp_hashinfo,
+ saddr, sport,
+ daddr, dport,
+ in->ifindex);
+
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ break;
+ case NFT_LOOKUP_ESTABLISHED:
+ sk = inet_lookup_established(net, &tcp_hashinfo,
+ saddr, sport, daddr, dport,
+ in->ifindex);
+ break;
+ default:
+ BUG();
+ }
+ break;
+ case IPPROTO_UDP:
+ sk = udp4_lib_lookup(net, saddr, sport, daddr, dport,
+ in->ifindex);
+ if (sk) {
+ int connected = (sk->sk_state == TCP_ESTABLISHED);
+ int wildcard = (inet_sk(sk)->inet_rcv_saddr == 0);
+
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
+ (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
+ sock_put(sk);
+ sk = NULL;
+ }
+ }
+ break;
+ default:
+ WARN_ON(1);
+ sk = NULL;
+ }
+
+ pr_debug("tproxy socket lookup: proto %u %08x:%u -> %08x:%u, lookup type: %d, sock %p\n",
+ protocol, ntohl(saddr), ntohs(sport), ntohl(daddr), ntohs(dport), lookup_type, sk);
+
+ return sk;
+}
+
+#ifdef XT_TPROXY_HAVE_IPV6
+static inline struct sock *
+nf_tproxy_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,
+ const enum nf_tproxy_lookup_t lookup_type)
+{
+ struct sock *sk;
+
+ switch (protocol) {
+ case IPPROTO_TCP:
+ switch (lookup_type) {
+ case NFT_LOOKUP_LISTENER:
+ sk = inet6_lookup_listener(net, &tcp_hashinfo,
+ saddr, sport,
+ daddr, ntohs(dport),
+ in->ifindex);
+
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ break;
+ case NFT_LOOKUP_ESTABLISHED:
+ sk = __inet6_lookup_established(net, &tcp_hashinfo,
+ saddr, sport, daddr, ntohs(dport),
+ in->ifindex);
+ break;
+ default:
+ BUG();
+ }
+ break;
+ case IPPROTO_UDP:
+ sk = udp6_lib_lookup(net, saddr, sport, daddr, dport,
+ in->ifindex);
+ if (sk) {
+ int connected = (sk->sk_state == TCP_ESTABLISHED);
+ int wildcard = ipv6_addr_any(&sk->sk_v6_rcv_saddr);
+
+ /* NOTE: we return listeners even if bound to
+ * 0.0.0.0, those are filtered out in
+ * xt_socket, since xt_TPROXY needs 0 bound
+ * listeners too
+ */
+ if ((lookup_type == NFT_LOOKUP_ESTABLISHED && (!connected || wildcard)) ||
+ (lookup_type == NFT_LOOKUP_LISTENER && connected)) {
+ sock_put(sk);
+ sk = NULL;
+ }
+ }
+ break;
+ default:
+ WARN_ON(1);
+ sk = NULL;
+ }
+
+ pr_debug("tproxy socket lookup: proto %u %pI6:%u -> %pI6:%u, lookup type: %d, sock %p\n",
+ protocol, saddr, ntohs(sport), daddr, ntohs(dport), lookup_type, sk);
+
+ return sk;
+}
+#endif
+
/**
- * tproxy_handle_time_wait4() - handle IPv4 TCP TIME_WAIT reopen redirections
+ * tproxy_handle_time_wait4 - handle IPv4 TCP TIME_WAIT reopen redirections
* @skb: The skb being processed.
* @laddr: IPv4 address to redirect to or zero.
* @lport: TCP port to redirect to or zero.
@@ -103,6 +275,15 @@ tproxy_handle_time_wait4(struct sk_buff *skb, __be32 laddr, __be16 lport,
return sk;
}
+/* assign a socket to the skb -- consumes sk */
+static void
+nf_tproxy_assign_sock(struct sk_buff *skb, struct sock *sk)
+{
+ skb_orphan(skb);
+ skb->sk = sk;
+ skb->destructor = sock_edemux;
+}
+
static unsigned int
tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
u_int32_t mark_mask, u_int32_t mark_value)
@@ -141,7 +322,7 @@ tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
skb->dev, NFT_LOOKUP_LISTENER);
/* NOTE: assign_sock consumes our sk reference */
- if (sk && nf_tproxy_assign_sock(skb, sk)) {
+ if (sk && tproxy_sk_is_transparent(sk)) {
/* This should be in a separate target, but we don't do multiple
targets on the same rule yet */
skb->mark = (skb->mark & ~mark_mask) ^ mark_value;
@@ -149,6 +330,8 @@ tproxy_tg4(struct sk_buff *skb, __be32 laddr, __be16 lport,
pr_debug("redirecting: proto %hhu %pI4:%hu -> %pI4:%hu, mark: %x\n",
iph->protocol, &iph->daddr, ntohs(hp->dest),
&laddr, ntohs(lport), skb->mark);
+
+ nf_tproxy_assign_sock(skb, sk);
return NF_ACCEPT;
}
@@ -204,7 +387,7 @@ tproxy_laddr6(struct sk_buff *skb, const struct in6_addr *user_laddr,
}
/**
- * tproxy_handle_time_wait6() - handle IPv6 TCP TIME_WAIT reopen redirections
+ * tproxy_handle_time_wait6 - handle IPv6 TCP TIME_WAIT reopen redirections
* @skb: The skb being processed.
* @tproto: Transport protocol.
* @thoff: Transport protocol header offset.
@@ -266,10 +449,10 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
struct sock *sk;
const struct in6_addr *laddr;
__be16 lport;
- int thoff;
+ int thoff = 0;
int tproto;
- tproto = ipv6_find_hdr(skb, &thoff, -1, NULL);
+ 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;
@@ -306,7 +489,7 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
par->in, NFT_LOOKUP_LISTENER);
/* NOTE: assign_sock consumes our sk reference */
- if (sk && nf_tproxy_assign_sock(skb, sk)) {
+ if (sk && tproxy_sk_is_transparent(sk)) {
/* This should be in a separate target, but we don't do multiple
targets on the same rule yet */
skb->mark = (skb->mark & ~tgi->mark_mask) ^ tgi->mark_value;
@@ -314,6 +497,8 @@ tproxy_tg6_v1(struct sk_buff *skb, const struct xt_action_param *par)
pr_debug("redirecting: proto %hhu %pI6:%hu -> %pI6:%hu, mark: %x\n",
tproto, &iph->saddr, ntohs(hp->source),
laddr, ntohs(lport), skb->mark);
+
+ nf_tproxy_assign_sock(skb, sk);
return NF_ACCEPT;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-05 08:18:31 +0000