On 17/09/13 11:43, Martin Storsjö wrote:
> On Tue, 17 Sep 2013, Luca Barbato wrote:
> 
>> On 17/09/13 11:34, Martin Storsjö wrote:
>>> On Mon, 16 Sep 2013, Luca Barbato wrote:
>>>
>>>> On 16/09/13 21:06, Martin Storsjö wrote:
>>>>> Since the number of channels is multiplied by 36 and assigned to
>>>>> to a uint16_t, make sure this calculation didn't overflow. (In
>>>>> certain cases the calculation could overflow leaving the
>>>>> truncated block_align at 0, leading to divisions by zero later.)
>>>>>
>>>>> Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
>>>>> CC: [email protected]
>>>>> ---
>>>>>  libavformat/xmv.c |    3 ++-
>>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>>
>>>>> diff --git a/libavformat/xmv.c b/libavformat/xmv.c
>>>>> index bc7c3c9..dd8a02d 100644
>>>>> --- a/libavformat/xmv.c
>>>>> +++ b/libavformat/xmv.c
>>>>> @@ -224,7 +224,8 @@ static int xmv_read_header(AVFormatContext *s)
>>>>>              av_log(s, AV_LOG_WARNING, "Unsupported 5.1 ADPCM audio
>>>>> stream "
>>>>>                                        "(0x%04X)\n", track->flags);
>>>>>
>>>>> -        if (!track->channels || !track->sample_rate) {
>>>>> +        if (!track->channels || !track->sample_rate ||
>>>>> +             track->channels >= UINT16_MAX/36) {
>>>>
>>>> Diego will complain about spaces, I would complain about magic numbers,
>>>> the idea is sound.
>>>
>>> Spaces added locally, what would you suggest doing about the magic
>>> numbers?
>>
>>
>> We have XMV_MIN_HEADER_SIZE already even if I'm not really sure it is
>> the same thing (didn't look at the code properly yet).
> 
> It's not directly related (and if it is, it's only a coincidence
> anyway). It needs to match whatever constant is used in the "block_align
> = 36*channels" multiplication.
> 

XMV_BLOCK_ALIGN_SIZE then.


> // Martin
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