Re: [PATCH] [media] atmel-isc: fix off-by-one comparison and out of bounds read issue

[Colin Ian King]

On 09/03/17 11:49, walter harms wrote:
> 
> 
> Am 09.03.2017 11:57, schrieb Hans Verkuil:
>> Hi Songjun,
>>
>> On 08/03/17 03:25, Wu, Songjun wrote:
>>> Hi Colin,
>>>
>>> Thank you for your comment.
>>> It is a bug, will be fixed in the next patch.
>>
>> Do you mean that you will provide a new patch for this? Is there anything
>> wrong with this patch? It seems reasonable to me.
>>
>> Regards,
>>
>> 	Hans
>>
> 
> 
> 
> perhaps he will make it a bit more readable, like:
> 
> *hist_count += i * (*hist_entry++);
> 
> *hist_count += hist_entry[i]*i;

As long as it gets fixed somehow, then I'm happy.

Colin
> 
> 
> re,
>  wh
>>>
>>> On 3/7/2017 22:30, Colin King wrote:
>>>> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>>>
>>>> The are only HIST_ENTRIES worth of entries in  hist_entry however the
>>>> for-loop is iterating one too many times leasing to a read access off
>>>> the end off the array ctrls->hist_entry.  Fix this by iterating by
>>>> the correct number of times.
>>>>
>>>> Detected by CoverityScan, CID#1415279 ("Out-of-bounds read")
>>>>
>>>> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>>>> ---
>>>>  drivers/media/platform/atmel/atmel-isc.c | 2 +-
>>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>>
>>>> diff --git a/drivers/media/platform/atmel/atmel-isc.c b/drivers/media/platform/atmel/atmel-isc.c
>>>> index b380a7d..7dacf8c 100644
>>>> --- a/drivers/media/platform/atmel/atmel-isc.c
>>>> +++ b/drivers/media/platform/atmel/atmel-isc.c
>>>> @@ -1298,7 +1298,7 @@ static void isc_hist_count(struct isc_device *isc)
>>>>      regmap_bulk_read(regmap, ISC_HIS_ENTRY, hist_entry, HIST_ENTRIES);
>>>>
>>>>      *hist_count = 0;
>>>> -    for (i = 0; i <= HIST_ENTRIES; i++)
>>>> +    for (i = 0; i < HIST_ENTRIES; i++)
>>>>          *hist_count += i * (*hist_entry++);
>>>>  }
>>>>
>>>>
>>
> 
> 
> 
> 
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