[NETFILTER]: Handle NAT in IPsec policy checks
Handle NAT of decapsulated IPsec packets by reconstructing the struct flowi
of the original packet from the conntrack information for IPsec policy
checks.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 79bb977..84506df 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -274,6 +274,20 @@
extern int nf_register_queue_rerouter(int pf, struct nf_queue_rerouter *rer);
extern int nf_unregister_queue_rerouter(int pf);
+#include <net/flow.h>
+extern void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
+
+static inline void
+nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family)
+{
+#ifdef CONFIG_IP_NF_NAT_NEEDED
+ void (*decodefn)(struct sk_buff *, struct flowi *);
+
+ if (family == AF_INET && (decodefn = ip_nat_decode_session) != NULL)
+ decodefn(skb, fl);
+#endif
+}
+
#ifdef CONFIG_PROC_FS
#include <linux/proc_fs.h>
extern struct proc_dir_entry *proc_net_netfilter;
@@ -282,6 +296,8 @@
#else /* !CONFIG_NETFILTER */
#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
static inline void nf_ct_attach(struct sk_buff *new, struct sk_buff *skb) {}
+static inline void
+nf_nat_decode_session(struct sk_buff *skb, struct flowi *fl, int family) {}
#endif /*CONFIG_NETFILTER*/
#endif /*__KERNEL__*/
diff --git a/net/dccp/ipv4.c b/net/dccp/ipv4.c
index 23ba177..00f9832 100644
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
@@ -986,6 +986,7 @@
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
goto discard_and_relse;
+ nf_reset(skb);
return sk_receive_skb(sk, skb);
@@ -1099,7 +1100,6 @@
kfree_skb(sk->sk_send_head);
sk->sk_send_head = NULL;
}
- nf_reset(skb);
/* Clean up a referenced DCCP bind bucket. */
if (inet_csk(sk)->icsk_bind_hash != NULL)
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index 4c637a1..3321092 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -86,6 +86,9 @@
}
EXPORT_SYMBOL(ip_route_me_harder);
+void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
+EXPORT_SYMBOL(ip_nat_decode_session);
+
/*
* Extra routing may needed on local out, as the QUEUE target never
* returns control to the table.
diff --git a/net/ipv4/netfilter/ip_nat_standalone.c b/net/ipv4/netfilter/ip_nat_standalone.c
index b518697..8b8a1f0 100644
--- a/net/ipv4/netfilter/ip_nat_standalone.c
+++ b/net/ipv4/netfilter/ip_nat_standalone.c
@@ -55,6 +55,44 @@
: ((hooknum) == NF_IP_LOCAL_IN ? "LOCAL_IN" \
: "*ERROR*")))
+#ifdef CONFIG_XFRM
+static void nat_decode_session(struct sk_buff *skb, struct flowi *fl)
+{
+ struct ip_conntrack *ct;
+ struct ip_conntrack_tuple *t;
+ enum ip_conntrack_info ctinfo;
+ enum ip_conntrack_dir dir;
+ unsigned long statusbit;
+
+ ct = ip_conntrack_get(skb, &ctinfo);
+ if (ct == NULL)
+ return;
+ dir = CTINFO2DIR(ctinfo);
+ t = &ct->tuplehash[dir].tuple;
+
+ if (dir == IP_CT_DIR_ORIGINAL)
+ statusbit = IPS_DST_NAT;
+ else
+ statusbit = IPS_SRC_NAT;
+
+ if (ct->status & statusbit) {
+ fl->fl4_dst = t->dst.ip;
+ if (t->dst.protonum == IPPROTO_TCP ||
+ t->dst.protonum == IPPROTO_UDP)
+ fl->fl_ip_dport = t->dst.u.tcp.port;
+ }
+
+ statusbit ^= IPS_NAT_MASK;
+
+ if (ct->status & statusbit) {
+ fl->fl4_src = t->src.ip;
+ if (t->dst.protonum == IPPROTO_TCP ||
+ t->dst.protonum == IPPROTO_UDP)
+ fl->fl_ip_sport = t->src.u.tcp.port;
+ }
+}
+#endif
+
static unsigned int
ip_nat_fn(unsigned int hooknum,
struct sk_buff **pskb,
@@ -330,10 +368,14 @@
if (!init) goto cleanup;
+#ifdef CONFIG_XFRM
+ BUG_ON(ip_nat_decode_session != NULL);
+ ip_nat_decode_session = nat_decode_session;
+#endif
ret = ip_nat_rule_init();
if (ret < 0) {
printk("ip_nat_init: can't setup rules.\n");
- goto cleanup_nothing;
+ goto cleanup_decode_session;
}
ret = nf_register_hook(&ip_nat_in_ops);
if (ret < 0) {
@@ -381,7 +423,11 @@
nf_unregister_hook(&ip_nat_in_ops);
cleanup_rule_init:
ip_nat_rule_cleanup();
- cleanup_nothing:
+ cleanup_decode_session:
+#ifdef CONFIG_XFRM
+ ip_nat_decode_session = NULL;
+ synchronize_net();
+#endif
return ret;
}
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index f2edc92..59614a9 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -22,6 +22,7 @@
#include <linux/workqueue.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
+#include <linux/netfilter.h>
#include <linux/module.h>
#include <net/xfrm.h>
#include <net/ip.h>
@@ -985,6 +986,7 @@
if (xfrm_decode_session(skb, &fl, family) < 0)
return 0;
+ nf_nat_decode_session(skb, &fl, family);
sk_sid = security_sk_sid(sk, &fl, fl_dir);