netdev - [PATCH AUTOSEL 5.4 025/187] netfilter: nf_queue: enqueue skbs with NULL dst

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Message-Id: <20191227174055.4923-25-sashal@kernel.org>
Date:   Fri, 27 Dec 2019 12:38:13 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Marco Oliverio <marco.oliverio@...aza.com>,
        Rocco Folino <rocco.folino@...aza.com>,
        Florian Westphal <fw@...len.de>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        Sasha Levin <sashal@...nel.org>,
        netfilter-devel@...r.kernel.org, coreteam@...filter.org,
        netdev@...r.kernel.org
Subject: [PATCH AUTOSEL 5.4 025/187] netfilter: nf_queue: enqueue skbs with NULL dst

From: Marco Oliverio <marco.oliverio@...aza.com>

[ Upstream commit 0b9173f4688dfa7c5d723426be1d979c24ce3d51 ]

Bridge packets that are forwarded have skb->dst == NULL and get
dropped by the check introduced by
b60a77386b1d4868f72f6353d35dabe5fbe981f2 (net: make skb_dst_force
return true when dst is refcounted).

To fix this we check skb_dst() before skb_dst_force(), so we don't
drop skb packet with dst == NULL. This holds also for skb at the
PRE_ROUTING hook so we remove the second check.

Fixes: b60a77386b1d ("net: make skb_dst_force return true when dst is refcounted")
Signed-off-by: Marco Oliverio <marco.oliverio@...aza.com>
Signed-off-by: Rocco Folino <rocco.folino@...aza.com>
Acked-by: Florian Westphal <fw@...len.de>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 net/netfilter/nf_queue.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netfilter/nf_queue.c b/net/netfilter/nf_queue.c
index a2b58de82600..f8f52ff99cfb 100644
--- a/net/netfilter/nf_queue.c
+++ b/net/netfilter/nf_queue.c
@@ -189,7 +189,7 @@ static int __nf_queue(struct sk_buff *skb, const struct nf_hook_state *state,
 		goto err;
 	}
 
-	if (!skb_dst_force(skb) && state->hook != NF_INET_PRE_ROUTING) {
+	if (skb_dst(skb) && !skb_dst_force(skb)) {
 		status = -ENETDOWN;
 		goto err;
 	}
-- 
2.20.1