From 7aaed57c5c2890634cfadf725173c7c68ea4cb4f Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Tue, 12 Jan 2016 08:58:00 -0800 Subject: [PATCH] phonet: properly unshare skbs in phonet_rcv() Ivaylo Dimitrov reported a regression caused by commit 7866a621043f ("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 Tested-by: Ivaylo Dimitrov Signed-off-by: Eric Dumazet Cc: Remi Denis-Courmont Signed-off-by: David S. Miller --- net/phonet/af_phonet.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c index 10d42f3220ab..f925753668a7 100644 --- a/net/phonet/af_phonet.c +++ b/net/phonet/af_phonet.c @@ -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; -- 2.20.1