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Re: [Qemu-devel] [PATCH v2] virtio-balloon: fix integer overflow in memo
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v2] virtio-balloon: fix integer overflow in memory stats feature |
Date: |
Tue, 16 Sep 2014 18:02:54 +0300 |
On Tue, Sep 16, 2014 at 09:39:50AM -0400, 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 manipulated as an int64_t variable.
>
> 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.
>
> This commit fix this bug by changing balloon_stats_change_timer()
> to take an int64_t and also it limits the polling interval value
> to UINT_MAX to avoid other kinds of overflow.
>
> Signed-off-by: Luiz Capitulino <address@hidden>
OK but pls remember to Cc qemu-stable on bugfixes.
> ---
> hw/virtio/virtio-balloon.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c
> index 2c30b3d..b5cf7ca 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);
> }
> @@ -170,6 +170,11 @@ static void balloon_stats_set_poll_interval(Object *obj,
> struct Visitor *v,
> return;
> }
>
> + if (value > UINT_MAX) {
> + error_setg(errp, "timer value is too big");
> + return;
> + }
> +
> if (value == s->stats_poll_interval) {
> return;
> }
> --
> 1.9.3
>