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Date: Mon, 16 Feb 2015 10:29:47 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH] virtio: validate the existence of
 handle_output before calling it
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To: Jason Wang <jasowang@redhat.com>
Cc: qemu-devel <qemu-devel@nongnu.org>



On 15/02/2015 03:35, Jason Wang wrote:
> 
> 
> On Sat, Feb 14, 2015 at 4:50 AM, Paolo Bonzini <pbonzini@redhat.com> wrote:
>>
>>
>> On 12/02/2015 04:05, Jason Wang wrote:
>>>  We don't validate the existence of handle_output which may let a buggy
>>>  guest to trigger a SIGSEV easily. Fix this by validate its existence
>>>  before.
>>>  
>>>  Cc: qemu-stable@nongnu.org
>>>  Cc: Anthony Liguori <aliguori@amazon.com>
>>>  Cc: Michael S. Tsirkin <mst@redhat.com>
>>>  Signed-off-by: Jason Wang <jasowang@redhat.com>
>>
>> Which queue was causing this?
>>
>> Paolo
> 
> The queue that was not used by the device. Though qemu does not use
> them, but it allows guest to do some basic programming. e.g: (for 1q
> virtio-net)
> 
> 1) write 10 to queue_sel
> 2) setup an arbitrary pfn
> 3) then notify queue 10

Oh, I see.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>