From: Michael S. Tsirkin <mst@redhat.com>
Date: Thu, 3 Apr 2014 16:51:23 +0000 (+0300)
Subject: hpet: fix buffer overrun on invalid state load
X-Git-Tag: qemu-xen-4.5.0-rc1^2~109
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=3c6066172ff591512e015ac933e056f6cc069527;p=qemu-upstream-4.5-testing.git

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 <anthony@codemonkey.ws>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit 3f1c49e2136fa08ab1ef3183fd55def308829584)
Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
---

diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index e15d6bcac..2792f89c6 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -239,6 +239,18 @@ 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;
@@ -307,6 +319,7 @@ 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()