diff mbox

[net] phonet: properly unshare skbs in phonet_rcv()

Message ID 1452617880.1223.21.camel@edumazet-glaptop2.roam.corp.google.com (mailing list archive)
State New, archived
Headers show

Commit Message

Eric Dumazet Jan. 12, 2016, 4:58 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

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 <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>
---
 net/phonet/af_phonet.c |    4 ++++
 1 file changed, 4 insertions(+)



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Comments

David Miller Jan. 12, 2016, 8:47 p.m. UTC | #1 
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 12 Jan 2016 08:58:00 -0800

> From: Eric Dumazet <edumazet@google.com>
> 
> 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 <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>

Applied and queued up for -stable, th anks Eric.
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diff mbox

Patch

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;