Commit 7aaed57c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

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: default avatarIvaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Tested-by: default avatarIvaylo Dimitrov <ivo.g.dimitrov.75@gmail.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Remi Denis-Courmont <courmisch@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d4618732
......@@ -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;
......
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