From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: netdev@vger.kernel.org, xma@us.ibm.com, davem@davemloft.net,
linux-kernel@vger.kernel.org, ebiederm@xmission.com
Subject: Re: [PATCH 5/6] vhost_net: fix use after free of vq->ubufs
Date: Tue, 17 Apr 2012 13:22:20 +0300 [thread overview]
Message-ID: <20120417102220.GC20905@redhat.com> (raw)
In-Reply-To: <4F8CE14E.5080508@redhat.com>
On Tue, Apr 17, 2012 at 11:19:42AM +0800, Jason Wang wrote:
> On 04/16/2012 09:28 PM, Michael S. Tsirkin wrote:
> >On Mon, Apr 16, 2012 at 02:08:25PM +0800, Jason Wang wrote:
> >>When zerocopy socket is used, ubufs pointer were used in handle_tx()
> >>without any validation. This would cause NULL pointer deference after
> >>it has been freed in vhost_net_set_backend(). Fix this by check the
> >>pointer before using it.
> >>
> >>Signed-off-by: Jason Wang<jasowang@redhat.com>
> >
> >OK so it's NULL dereference and not user after free :)
> >Also could you clarify how does this happen pls?
> >Don't we always initialize ubufs when vhost_sock_zcopy is set?
>
> The problem happens when we want to disable backend. At this time
> ubufs were assigned to NULL and it may be dereferenced by
> handle_tx():
Heh, I see. How about
- zcopy = vhost_sock_zcopy(sock);
+ zcopy = vq->ubufs;
--
MST
next prev parent reply other threads:[~2012-04-17 10:22 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-16 6:07 [PATCH 1/6] macvtap: zerocopy: fix offset calculation when building skb Jason Wang
2012-04-16 6:07 ` [PATCH 2/6] macvtap: zerocopy: fix truesize underestimation Jason Wang
2012-04-16 7:14 ` Michael S. Tsirkin
2012-04-16 8:23 ` Jason Wang
2012-04-16 8:49 ` Eric Dumazet
2012-04-16 13:25 ` Michael S. Tsirkin
2012-04-16 6:08 ` [PATCH 3/6] macvtap: zerocopy: validate vector length before pinning user pages Jason Wang
2012-04-16 6:53 ` Eric Dumazet
2012-04-16 8:21 ` Jason Wang
2012-04-17 5:33 ` Eric Dumazet
2012-04-17 5:43 ` Michael S. Tsirkin
2012-04-17 6:19 ` Michael S. Tsirkin
2012-04-16 7:58 ` Michael S. Tsirkin
2012-04-16 6:08 ` [PATCH 4/6] macvtap: zerocopy: set SKBTX_DEV_ZEROCOPY only when skb is built successfully Jason Wang
2012-04-16 6:08 ` [PATCH 5/6] vhost_net: fix use after free of vq->ubufs Jason Wang
2012-04-16 13:28 ` Michael S. Tsirkin
2012-04-17 3:19 ` Jason Wang
2012-04-17 10:22 ` Michael S. Tsirkin [this message]
2012-04-17 10:47 ` Jason Wang
2012-04-16 6:08 ` [PATCH 6/6] vhost_net: don't poll on -EFAULT Jason Wang
2012-04-16 7:16 ` Michael S. Tsirkin
2012-04-16 8:28 ` Jason Wang
2012-04-16 13:39 ` Michael S. Tsirkin
2012-04-17 3:27 ` Jason Wang
2012-04-17 4:57 ` Michael S. Tsirkin
2012-04-17 5:54 ` Jason Wang
2012-04-17 6:07 ` Michael S. Tsirkin
2012-04-17 6:30 ` Jason Wang
2012-04-17 10:18 ` Michael S. Tsirkin
2012-04-17 10:46 ` Jason Wang
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