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

[walter harms <wharms@bfs.de>]

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;


re,
 wh
>>
>> On 3/7/2017 22:30, Colin King wrote:
>>> From: Colin Ian King <colin.king@canonical.com>
>>>
>>> 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@canonical.com>
>>> ---
>>>  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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