netfilter: xt_hashlimit: fix lock imbalance

BugLink: http://bugs.launchpad.net/bugs/1756100
commit de526f401284e1638d4c97cb5a4c292ac3f37655 upstream.

syszkaller found that rcu was not held in hashlimit_mt_common()

We only need to enable BH at this point.

Fixes: bea74641e378 ("netfilter: xt_hashlimit: add rate match mode")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzkaller <syzkaller@googlegroups.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index 5da8746f7b88ff4c9446f256e542e823a6a561b0..b8a3e740ffd4eefec9483e09220b8b630a5e8f73 100644 (file)
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -774,7 +774,7 @@ hashlimit_mt_common(const struct sk_buff *skb, struct xt_action_param *par,
                if (!dh->rateinfo.prev_window &&
                    (dh->rateinfo.current_rate <= dh->rateinfo.burst)) {
                        spin_unlock(&dh->lock);
-                       rcu_read_unlock_bh();
+                       local_bh_enable();
                        return !(cfg->mode & XT_HASHLIMIT_INVERT);
                } else {
                        goto overlimit;