From: "Michael S. Tsirkin" Date: Thu, 3 Apr 2014 19:51:23 +0300 Subject: [PATCH] hpet: fix buffer overrun on invalid state load CVE-2013-4527 hw/timer/hpet.c buffer overrun hpet is a VARRAY with a uint8 size but static array of 32 To fix, make sure num_timers is valid using VMSTATE_VALID hook. Reported-by: Anthony Liguori Signed-off-by: Michael S. Tsirkin Reviewed-by: Dr. David Alan Gilbert Signed-off-by: Juan Quintela (cherry picked from commit 3f1c49e2136fa08ab1ef3183fd55def308829584) --- hw/timer/hpet.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c index 648b383..d4d52f1 100644 --- a/hw/timer/hpet.c +++ b/hw/timer/hpet.c @@ -228,6 +228,18 @@ static int hpet_pre_load(void *opaque) return 0; } +static bool hpet_validate_num_timers(void *opaque, int version_id) +{ + HPETState *s = opaque; + + if (s->num_timers < HPET_MIN_TIMERS) { + return false; + } else if (s->num_timers > HPET_MAX_TIMERS) { + return false; + } + return true; +} + static int hpet_post_load(void *opaque, int version_id) { HPETState *s = opaque; @@ -296,6 +308,7 @@ static const VMStateDescription vmstate_hpet = { VMSTATE_UINT64(isr, HPETState), VMSTATE_UINT64(hpet_counter, HPETState), VMSTATE_UINT8_V(num_timers, HPETState, 2), + VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers), VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0, vmstate_hpet_timer, HPETTimer), VMSTATE_END_OF_LIST()