From 4b41911968cb53458b86b027f0d028e38618df46 Mon Sep 17 00:00:00 2001
From: Michael S. Tsirkin <mst@redhat.com>
Date: Wed, 14 May 2014 08:52:54 +0200
Subject: [PATCH 23/31] hpet: fix buffer overrun on invalid state load

RH-Author: Michael S. Tsirkin <mst@redhat.com>
Message-id: <1400057538-6975-5-git-send-email-mst@redhat.com>
Patchwork-id: 58871
O-Subject: [PATCH qemu-kvm RHEL7.1 4/5] hpet: fix buffer overrun on invalid state load
Bugzilla: 1095707
RH-Acked-by: Dr. David Alan Gilbert (git) <dgilbert@redhat.com>
RH-Acked-by: Marcel Apfelbaum <marcel.a@redhat.com>
RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
RH-Acked-by: Juan Quintela <quintela@redhat.com>

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)

Tested: lightly on developer's box
Brew build: http://brewweb.devel.redhat.com/brew/taskinfo?taskID=7452039
Bugzilla:1095707
---
 hw/timer/hpet.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 hw/timer/hpet.c |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/hw/timer/hpet.c b/hw/timer/hpet.c
index dd486a1..54ffa49 100644
--- a/hw/timer/hpet.c
+++ b/hw/timer/hpet.c
@@ -222,6 +222,18 @@ 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;
@@ -290,6 +302,7 @@ 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()
-- 
1.7.1