[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>

1 files changed, 6 insertions, 7 deletions

diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 836541e509fe..0f5830779b44 100644
--- 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);