netdev - [PATCH net] pppoe: only process PADT targeted at local interfaces

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Message-ID: <87314848e98d74e88b3c3b2504566a7691f5a8e9.1589451271.git.gnault@redhat.com>
Date:   Thu, 14 May 2020 12:15:39 +0200
From:   Guillaume Nault <gnault@...hat.com>
To:     David Miller <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>
Cc:     netdev@...r.kernel.org,
        David Balažic <xerces9@...il.com>
Subject: [PATCH net] pppoe: only process PADT targeted at local interfaces

We don't want to disconnect a session because of a stray PADT arriving
while the interface is in promiscuous mode.
Furthermore, multicast and broadcast packets make no sense here, so
only PACKET_HOST is accepted.

Reported-by: David Balažic <xerces9@...il.com>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Guillaume Nault <gnault@...hat.com>
---
 drivers/net/ppp/pppoe.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/ppp/pppoe.c b/drivers/net/ppp/pppoe.c
index d760a36db28c..beedaad08255 100644
--- a/drivers/net/ppp/pppoe.c
+++ b/drivers/net/ppp/pppoe.c
@@ -490,6 +490,9 @@ static int pppoe_disc_rcv(struct sk_buff *skb, struct net_device *dev,
 	if (!skb)
 		goto out;
 
+	if (skb->pkt_type != PACKET_HOST)
+		goto abort;
+
 	if (!pskb_may_pull(skb, sizeof(struct pppoe_hdr)))
 		goto abort;
 
-- 
2.21.1