From: Cornelia Huck <cohuck@redhat.com>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, eric.auger@redhat.com
Subject: Re: [PATCH] vfio/type1: Limit DMA mappings per container
Date: Tue, 2 Apr 2019 16:58:35 +0200 [thread overview]
Message-ID: <20190402165835.53d4ec9b.cohuck@redhat.com> (raw)
In-Reply-To: <155414977872.12780.13728555131525362206.stgit@gimli.home>
On Mon, 01 Apr 2019 14:16:52 -0600
Alex Williamson <alex.williamson@redhat.com> wrote:
> Memory backed DMA mappings are accounted against a user's locked
> memory limit, including multiple mappings of the same memory. This
> accounting bounds the number of such mappings that a user can create.
> However, DMA mappings that are not backed by memory, such as DMA
> mappings of device MMIO via mmaps, do not make use of page pinning
> and therefore do not count against the user's locked memory limit.
> These mappings still consume memory, but the memory is not well
> associated to the process for the purpose of oom killing a task.
>
> To add bounding on this use case, we introduce a limit to the total
> number of concurrent DMA mappings that a user is allowed to create.
> This limit is exposed as a tunable module option where the default
> value of 64K is expected to be well in excess of any reasonable use
> case (a large virtual machine configuration would typically only make
> use of tens of concurrent mappings).
>
> This fixes CVE-2019-3882.
>
> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
> drivers/vfio/vfio_iommu_type1.c | 14 ++++++++++++++
> 1 file changed, 14 insertions(+)
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
prev parent reply other threads:[~2019-04-02 14:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-01 20:16 [PATCH] vfio/type1: Limit DMA mappings per container Alex Williamson
2019-04-02 2:41 ` Peter Xu
2019-04-02 4:34 ` Alex Williamson
2019-04-02 5:18 ` Peter Xu
2019-04-02 14:40 ` Alex Williamson
2019-04-02 14:58 ` Cornelia Huck [this message]
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