Commit 1f9296b5 authored Sep 15, 2014 by Luiz Capitulino

virtio-balloon: fix integer overflow in memory stats feature



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 <lcapitulino@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

parent e5554e20

hw/virtio/virtio-balloon.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -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;
		}