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From: Kevin Wolf <kwolf@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: qemu-devel@nongnu.org, mreitz@redhat.com,
	Li Qiang <liq3ea@gmail.com>, Keith Busch <keith.busch@intel.com>,
	qemu-block@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] nvme: fix out-of-bounds access to the CMB
Date: Thu, 22 Nov 2018 15:54:29 +0100	[thread overview]
Message-ID: <20181122145429.GD31879@linux.fritz.box> (raw)
In-Reply-To: <20181120184148.22501-1-pbonzini@redhat.com>

Am 20.11.2018 um 19:41 hat Paolo Bonzini geschrieben:
> Because the CMB BAR has a min_access_size of 2, if you read the last
> byte it will try to memcpy *2* bytes from n->cmbuf, causing an off-by-one
> error.  This is CVE-2018-16847.
> 
> Another way to fix this might be to register the CMB as a RAM memory
> region, which would also be more efficient.  However, that might be a
> change for big-endian machines; I didn't think this through and I don't
> know how real hardware works.  Add a basic testcase for the CMB in case
> somebody does this change later on.
> 
> Cc: Keith Busch <keith.busch@intel.com>
> Cc: qemu-block@nongnu.org
> Reported-by: Li Qiang <liq3ea@gmail.com>
> Reviewed-by: Li Qiang <liq3ea@gmail.com>
> Tested-by: Li Qiang <liq3ea@gmail.com>
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Thanks, applied to the block branch and reverted 5e3c0220d7.

Kevin

  parent reply	other threads:[~2018-11-22 14:54 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-20 18:41 [Qemu-devel] [PATCH] nvme: fix out-of-bounds access to the CMB Paolo Bonzini
2018-11-20 21:20 ` Philippe Mathieu-Daudé
2018-11-22  6:37 ` no-reply
2018-11-22 14:54 ` Kevin Wolf [this message]
2018-11-22 17:01 ` Peter Maydell

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