netdev - [PATCH net] netfilter: xt_hashlimit: fix lock imbalance

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Date:   Mon, 12 Feb 2018 08:11:48 -0800
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Pablo Neira Ayuso <pablo@...filter.org>,
        Florian Westphal <fw@...len.de>
Cc:     Vishwanath Pai <vpai@...mai.com>, netdev <netdev@...r.kernel.org>
Subject: [PATCH net] netfilter: xt_hashlimit: fix lock imbalance

From: Eric Dumazet <edumazet@...gle.com>

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@...gle.com>
Reported-by: syzkaller <syzkaller@...glegroups.com>
---
 net/netfilter/xt_hashlimit.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index ca6847403ca218c478d208080aab3e3c92a0a615..1fea48b4182f7cd5669b9c5e7100b2735cc590e7 100644
--- 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;