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Re: [Qemu-devel] [PATCH v3] virtio: add check for descriptor's mapped ad
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [PATCH v3] virtio: add check for descriptor's mapped address |
Date: |
Mon, 19 Sep 2016 21:02:27 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 |
On 09/19/16 20:25, P J P wrote:
> From: Prasad J Pandit <address@hidden>
>
> virtio back end uses set of buffers to facilitate I/O operations.
> If its size is too large, 'cpu_physical_memory_map' could return
> a null address. This would result in a null dereference while
> un-mapping descriptors. Add check to avoid it.
>
> Reported-by: Qinghao Tang <address@hidden>
> Signed-off-by: Prasad J Pandit <address@hidden>
> ---
> hw/virtio/virtio.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> Update per:
> -> https://lists.gnu.org/archive/html/qemu-devel/2016-09/msg04329.html
>
> diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> index 15ee3a7..a4ebf8c 100644
> --- a/hw/virtio/virtio.c
> +++ b/hw/virtio/virtio.c
> @@ -472,6 +472,11 @@ static void virtqueue_map_desc(unsigned int *p_num_sg,
> hwaddr *addr, struct iove
> }
>
> iov[num_sg].iov_base = cpu_physical_memory_map(pa, &len, is_write);
> + if (!iov[num_sg].iov_base) {
> + error_report("virtio: bogus descriptor or out of resources");
> + exit(1);
> + }
> +
> iov[num_sg].iov_len = len;
> addr[num_sg] = pa;
>
>
Reviewed-by: Laszlo Ersek <address@hidden>