[NETFILTER]: ip_conntrack: fix NAT helper unload races

[deliverable/linux.git] / net / ipv4 / netfilter / ip_conntrack_tftp.c

diff --git a/net/ipv4/netfilter/ip_conntrack_tftp.c b/net/ipv4/netfilter/ip_conntrack_tftp.c
index fe0b634dd37761fd15d341698cf45c0158485631..ef56de2eff0c71edc8dd8f29c1d2e431dc041f32 100644 (file)
--- a/net/ipv4/netfilter/ip_conntrack_tftp.c
+++ b/net/ipv4/netfilter/ip_conntrack_tftp.c
@@ -50,6 +50,7 @@ static int tftp_help(struct sk_buff **pskb,
        struct tftphdr _tftph, *tfh;
        struct ip_conntrack_expect *exp;
        unsigned int ret = NF_ACCEPT;
+       typeof(ip_nat_tftp_hook) ip_nat_tftp;
 
        tfh = skb_header_pointer(*pskb,
                                 (*pskb)->nh.iph->ihl*4+sizeof(struct udphdr),
@@ -81,8 +82,9 @@ static int tftp_help(struct sk_buff **pskb,
                DEBUGP("expect: ");
                DUMP_TUPLE(&exp->tuple);
                DUMP_TUPLE(&exp->mask);
-               if (ip_nat_tftp_hook)
-                       ret = ip_nat_tftp_hook(pskb, ctinfo, exp);
+               ip_nat_tftp = rcu_dereference(ip_nat_tftp_hook);
+               if (ip_nat_tftp)
+                       ret = ip_nat_tftp(pskb, ctinfo, exp);
                else if (ip_conntrack_expect_related(exp) != 0)
                        ret = NF_DROP;
                ip_conntrack_expect_put(exp);