[NETFILTER]: nf_conntrack: fix the race on assign helper to new conntrack

The found helper cannot be assigned to conntrack after unlocking
nf_conntrack_lock. This tries to find helper to assign again.

Signed-off-by: Yasuyuki Kozakai <yasuyuki.kozakai@toshiba.co.jp>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 836541e509fe14e67e04c10012b94ae594c0446b..0f5830779b444c2b73102c5531a9b0aa6bd4c83a 100644 (file)
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -893,12 +893,6 @@ __nf_conntrack_alloc(const struct nf_conntrack_tuple *orig,
 
        memset(conntrack, 0, nf_ct_cache[features].size);
        conntrack->features = features;
-       if (helper) {
-               struct nf_conn_help *help = nfct_help(conntrack);
-               NF_CT_ASSERT(help);
-               help->helper = helper;
-       }
-
        atomic_set(&conntrack->ct_general.use, 1);
        conntrack->ct_general.destroy = destroy_conntrack;
        conntrack->tuplehash[IP_CT_DIR_ORIGINAL].tuple = *orig;
@@ -982,8 +976,13 @@ init_conntrack(const struct nf_conntrack_tuple *tuple,
 #endif
                nf_conntrack_get(&conntrack->master->ct_general);
                NF_CT_STAT_INC(expect_new);
-       } else
+       } else {
+               struct nf_conn_help *help = nfct_help(conntrack);
+
+               if (help)
+                       help->helper = __nf_ct_helper_find(&repl_tuple);
                NF_CT_STAT_INC(new);
+       }
 
        /* Overload tuple linked list to put us in unconfirmed list. */
        list_add(&conntrack->tuplehash[IP_CT_DIR_ORIGINAL].list, &unconfirmed);