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Date: Fri, 25 Nov 2011 12:55:21 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 1.0] qiov: prevent double free or
	use-after-free
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To: Kevin Wolf <kwolf@redhat.com>
Cc: qemu-devel@nongnu.org

On 11/25/2011 12:56 PM, Kevin Wolf wrote:
>> qemu_iovec_destroy does not clear the QEMUIOVector fully, and the data
>> >  could thus be used after free or freed again.  While I do not know any
>> >  example in the tree, I observed this using virtio-scsi (and SCSI
>> >  scatter/gather) when canceling DMA requests.
>> >
>> >  Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> This isn't a bug fix for itself, it just makes bugs in other code more
> visible, right? It probably makes sense to do this change, but I'm not
> sure about doing it for 1.0.

It is a fix.  NULLing the pointer prevents double-free bugs, and setting 
niov/nalloc to 0 should prevent use-after-free.

Paolo