netdev - Re: [net] net: fix double free issue of skbuff

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Message-ID: <1456751411.4837.25.camel@redhat.com>
Date:	Mon, 29 Feb 2016 14:10:11 +0100
From:	Paolo Abeni <pabeni@...hat.com>
To:	Zhang Shengju <zhangshengju@...s.chinamobile.com>
Cc:	davem@...emloft.net, netdev@...r.kernel.org
Subject: Re: [net] net: fix double free issue of skbuff

On Mon, 2016-02-29 at 12:22 +0000, Zhang Shengju wrote:
> If skb_reorder_vlan_header() failed, skb is freed and NULL is returned.
> Then at skb_vlan_untag(), it will free skbuff again which cause double
> free.

On skb_reorder_vlan_header() failure, skb_vlan_untag() will call
kfree_skb() using the return value of skb_reorder_vlan_header(), that is
NULL. kfree_skb() is a noop when the argument is NULL.

The current code seams safe.

Paolo