[NETFILTER]: nf_nat: don't add NAT extension for confirmed conntracks

Adding extensions to confirmed conntracks is not allowed to avoid races
on reallocation. Don't setup NAT for confirmed conntracks in case NAT
module is loaded late.

The has one side-effect, the connections existing before the NAT module
was loaded won't enter the bysource hash. The only case where this actually
makes a difference is in case of SNAT to a multirange where the IP before
NAT is also part of the range. Since old connections don't enter the
bysource hash the first new connection from the IP will have a new address
selected. This shouldn't matter at all.

Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/include/net/netfilter/nf_nat_rule.h b/include/net/netfilter/nf_nat_rule.h
index 75d1825031d712fa420a3af403fe0ad78e593b90..e4a18ae361c62fd543999554461299ad86ba3714 100644 (file)
--- a/include/net/netfilter/nf_nat_rule.h
+++ b/include/net/netfilter/nf_nat_rule.h
@@ -14,7 +14,4 @@ extern int nf_nat_rule_find(struct sk_buff *skb,
 
 extern unsigned int
 alloc_null_binding(struct nf_conn *ct, unsigned int hooknum);
-
-extern unsigned int
-alloc_null_binding_confirmed(struct nf_conn *ct, unsigned int hooknum);
 #endif /* _NF_NAT_RULE_H */

diff --git a/net/ipv4/netfilter/nf_nat_rule.c b/net/ipv4/netfilter/nf_nat_rule.c
index ebe0c7903ae964823f5552edb3499e69ebde1d42..e8b4d0d4439ea51fb0b638ae46b1b5a86ca6aca6 100644 (file)
--- a/net/ipv4/netfilter/nf_nat_rule.c
+++ b/net/ipv4/netfilter/nf_nat_rule.c
@@ -188,25 +188,6 @@ alloc_null_binding(struct nf_conn *ct, unsigned int hooknum)
        return nf_nat_setup_info(ct, &range, HOOK2MANIP(hooknum));
 }
 
-unsigned int
-alloc_null_binding_confirmed(struct nf_conn *ct, unsigned int hooknum)
-{
-       __be32 ip
-               = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
-                  ? ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip
-                  : ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u3.ip);
-       __be16 all
-               = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC
-                  ? ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u.all
-                  : ct->tuplehash[IP_CT_DIR_REPLY].tuple.src.u.all);
-       struct nf_nat_range range
-               = { IP_NAT_RANGE_MAP_IPS, ip, ip, { all }, { all } };
-
-       pr_debug("Allocating NULL binding for confirmed %p (%u.%u.%u.%u)\n",
-                ct, NIPQUAD(ip));
-       return nf_nat_setup_info(ct, &range, HOOK2MANIP(hooknum));
-}
-
 int nf_nat_rule_find(struct sk_buff *skb,
                     unsigned int hooknum,
                     const struct net_device *in,

diff --git a/net/ipv4/netfilter/nf_nat_standalone.c b/net/ipv4/netfilter/nf_nat_standalone.c
index c362f672755a59dcd0c404a18d8b74441bbad9ca..a366b5865b9c3c3b0556a5ebb772097b64299ac4 100644 (file)
--- a/net/ipv4/netfilter/nf_nat_standalone.c
+++ b/net/ipv4/netfilter/nf_nat_standalone.c
@@ -102,6 +102,9 @@ nf_nat_fn(unsigned int hooknum,
 
        nat = nfct_nat(ct);
        if (!nat) {
+               /* NAT module was loaded late. */
+               if (nf_ct_is_confirmed(ct))
+                       return NF_ACCEPT;
                nat = nf_ct_ext_add(ct, NF_CT_EXT_NAT, GFP_ATOMIC);
                if (nat == NULL) {
                        pr_debug("failed to add NAT extension\n");
@@ -127,10 +130,7 @@ nf_nat_fn(unsigned int hooknum,
                if (!nf_nat_initialized(ct, maniptype)) {
                        unsigned int ret;
 
-                       if (unlikely(nf_ct_is_confirmed(ct)))
-                               /* NAT module was loaded late */
-                               ret = alloc_null_binding_confirmed(ct, hooknum);
-                       else if (hooknum == NF_INET_LOCAL_IN)
+                       if (hooknum == NF_INET_LOCAL_IN)
                                /* LOCAL_IN hook doesn't have a chain!  */
                                ret = alloc_null_binding(ct, hooknum);
                        else