Re: [Qemu-devel] [PATCH 2/2] xen-pt: fix Out-of-bounds read

[Gonglei]

On 2015/2/10 15:00, Stefano Stabellini wrote:
> On Tue, 10 Feb 2015, Gonglei wrote:
>> On 2015/2/10 14:39, Stefano Stabellini wrote:
>>> On Sat, 31 Jan 2015, address@hidden wrote:
>>>> From: Gonglei <address@hidden>
>>>>
>>>> The array length of s->real_device.io_regions[] is
>>>> "PCI_NUM_REGIONS - 1". Add a check, just make Coverity happy.
>>>>
>>>> Signed-off-by: Gonglei <address@hidden>
>>>> ---
>>>>  hw/xen/xen_pt_config_init.c | 5 +++++
>>>>  1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
>>>> index 710fe50..3c8b0f1 100644
>>>> --- a/hw/xen/xen_pt_config_init.c
>>>> +++ b/hw/xen/xen_pt_config_init.c
>>>> @@ -443,6 +443,11 @@ static int xen_pt_bar_reg_read(XenPCIPassthroughState 
>>>> *s, XenPTReg *cfg_entry,
>>>>          return -1;
>>>>      }
>>>>  
>>>> +    if (index == PCI_ROM_SLOT) {
>>>> +        XEN_PT_ERR(&s->dev, "Internal error: Access violation at ROM 
>>>> BAR.\n");
>>>> +        return -1;
>>>> +    }
>>>
>>> Could you please fix the boundaries of the check just above?
>>> Also please avoid using PCI_ROM_SLOT for the array index check, simply
>>> use PCI_NUM_REGIONS.
>>>
>> You meaning is changing the below check:
>>
>> if (index < 0 || index >= PCI_NUM_REGIONS - 1) {
>>         XEN_PT_ERR(&s->dev, "Internal error: Invalid BAR index [%d].\n", 
>> index);
>>         return -1;
>>     }
>>
>> Isn't it?
>  
> that's right
> 
OK, will do, thanks.

Regards,
-Gonglei