Re: [Qemu-devel] [PATCH 1/3] arm: check bit index before use

[liqsub1]

2018-10-22 

liqsub1 



发件人：P J P <address@hidden>
发送时间：2018-10-23 01:39
主题：[Qemu-devel] [PATCH 1/3] arm: check bit index before use
收件人："Qemu Developers"<address@hidden>
抄送："Peter Maydell"<address@hidden>,"Moguofang"<address@hidden>,"Prasad J 
Pandit"<address@hidden>

From: Prasad J Pandit <address@hidden> 

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 <address@hidden> 
Signed-off-by: Prasad J Pandit <address@hidden> 
--- 
 hw/arm/strongarm.c | 4 +++- 
 1 file changed, 3 insertions(+), 1 deletion(-) 

diff --git a/hw/arm/strongarm.c b/hw/arm/strongarm.c 
index ec2627374d..3dda75feaf 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 < sizeof(s->handler) / sizeof(s->handler[0])) { 

Hello Prasad,
Maybe you can use ARRAY_SIZE here.

Thanks,
Li Qiang

+            qemu_set_irq(s->handler[bit], (level >> bit) & 1); 
+        } 
     } 



  
     s->prev_level = level; 
--  
2.17.2