[Qemu-devel] [PATCH v1] arm: check bit index before usage

[P J P <ppandit@redhat.com>]

From: Prasad J Pandit <pjp@fedoraproject.org>

While performing gpio write via strongarm_gpio_handler_update
routine, the 'bit' index could access beyond s->handler[28] array.
Add check to avoid OOB access.

Reported-by: Moguofang <moguofang@huawei.com>
Signed-off-by: Prasad J Pandit <pjp@fedoraproject.org>
---
 hw/arm/strongarm.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Update v1: use ARRAY_SIZE macro
  -> https://lists.gnu.org/archive/html/qemu-devel/2018-10/msg04826.html

diff --git a/hw/arm/strongarm.c b/hw/arm/strongarm.c
index ec2627374d..9225b1ba6e 100644
--- a/hw/arm/strongarm.c
+++ b/hw/arm/strongarm.c
@@ -532,7 +532,9 @@ static void strongarm_gpio_handler_update(StrongARMGPIOInfo *s)
 
     for (diff = s->prev_level ^ level; diff; diff ^= 1 << bit) {
         bit = ctz32(diff);
-        qemu_set_irq(s->handler[bit], (level >> bit) & 1);
+        if (bit < ARRAY_SIZE(s->handler)) {
+            qemu_set_irq(s->handler[bit], (level >> bit) & 1);
+        }
     }
 
     s->prev_level = level;
-- 
2.17.2