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From: Peter Maydell <peter.maydell@linaro.org>
Date: Mon, 31 Mar 2014 16:40:41 +0100
Message-ID: <CAFEAcA8fsRikwSMqsEHEzkcM9N-ao+icntkRnk7nrqWEX=uNew@mail.gmail.com>
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Subject: Re: [Qemu-devel] [PATCH v4 12/30] vmstate: fix buffer overflow in
	target-arm/machine.c
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Michael Roth <mdroth@linux.vnet.ibm.com>, Juan Quintela <quintela@redhat.com>, Alexey Kardashevskiy <aik@ozlabs.ru>, qemu-stable <qemu-stable@nongnu.org>, QEMU Developers <qemu-devel@nongnu.org>, Anthony Liguori <anthony@codemonkey.ws>, =?UTF-8?Q?Andreas_F=C3=A4rber?= <afaerber@suse.de>, Dave Gilbert <dgilbert@redhat.com>

On 31 March 2014 15:16, Michael S. Tsirkin <mst@redhat.com> wrote:
> CVE-2013-4531
>
> cpreg_vmstate_indexes is a VARRAY_INT32. A negative value for
> cpreg_vmstate_array_len will cause a buffer overflow.
>
> VMSTATE_INT32_LE was supposed to protect against this
> but doesn't because it doesn't validate that input is
> non-negative.
>
> Fix this macro to valide the value appropriately.
>
> The only other user of VMSTATE_INT32_LE doesn't
> ever use negative numbers so it doesn't care.

This fixes the bug, but it's rather unintuitive semantics
for an INT32_LE not to simply do a signed comparison...
Maybe rename the macro?

thanks
-- PMM