Re: [Qemu-devel] [PATCH] virtio-balloon: fix buffer overflow in memory stats feature

[Eric Blake <eblake@redhat.com>]

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On 09/15/2014 12:09 PM, Luiz Capitulino wrote:
> When a QMP client changes the polling interval time by setting
> the guest-stats-polling-interval property, the interval value
> is stored and manipuled as an int64_t variable.
> 

s/manipuled/manipulated/

> However, the balloon_stats_change_timer() function, which is
> used to set the actual timer with the interval value, takes
> an int instead, causing an overflow for big interval values.
> 
> Fix it.
> 
> Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
> ---
>  hw/virtio/virtio-balloon.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 2c30b3d..9629264 100644
> --- a/hw/virtio/virtio-balloon.c
> +++ b/hw/virtio/virtio-balloon.c
> @@ -87,7 +87,7 @@ static void balloon_stats_destroy_timer(VirtIOBalloon *s)
>      }
>  }
>  
> -static void balloon_stats_change_timer(VirtIOBalloon *s, int secs)
> +static void balloon_stats_change_timer(VirtIOBalloon *s, int64_t secs)
>  {
>      timer_mod(s->stats_timer, qemu_clock_get_ms(QEMU_CLOCK_VIRTUAL) + secs * 1000);

secs * 1000 can still overflow for (really large) values, do we care
about that?

-- 
Eric Blake   eblake redhat com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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