Commit 7aaed57c authored Jan 12, 2016 by Eric Dumazet Committed by David S. Miller Jan 12, 2016

phonet: properly unshare skbs in phonet_rcv()



Ivaylo Dimitrov reported a regression caused by commit 7866a621
("dev: add per net_device packet type chains").

skb->dev becomes NULL and we crash in __netif_receive_skb_core().

Before above commit, different kind of bugs or corruptions could happen
without major crash.

But the root cause is that phonet_rcv() can queue skb without checking
if skb is shared or not.

Many thanks to Ivaylo Dimitrov for his help, diagnosis and tests.

Reported-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Tested-by: Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Remi Denis-Courmont <courmisch@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent d4618732

net/phonet/af_phonet.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -377,6 +377,10 @@ static int phonet_rcv(struct sk_buff skb, struct net_device dev,
		struct sockaddr_pn sa;
		u16 len;

		skb = skb_share_check(skb, GFP_ATOMIC);
		if (!skb)
		return NET_RX_DROP;

		/* check we have at least a full Phonet header */
		if (!pskb_pull(skb, sizeof(struct phonethdr)))
		goto out;