[FFmpeg-devel] [PATCH 2/7] 4xm: prevent overflow during block alignment calculation

[Andreas Cadhalpun]

On 16.12.2016 03:33, Rodger Combs wrote:
> 
>> On Dec 15, 2016, at 20:32, Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> wrote:
>>
>> Signed-off-by: Andreas Cadhalpun <Andreas.Cadhalpun at googlemail.com>
>> ---
>> libavformat/4xm.c | 1 +
>> 1 file changed, 1 insertion(+)
>>
>> diff --git a/libavformat/4xm.c b/libavformat/4xm.c
>> index 2758b69..9332f78 100644
>> --- a/libavformat/4xm.c
>> +++ b/libavformat/4xm.c
>> @@ -187,6 +187,7 @@ static int parse_strk(AVFormatContext *s,
>>     st->codecpar->bit_rate              = (int64_t)st->codecpar->channels *
>>                                           st->codecpar->sample_rate *
>>                                           st->codecpar->bits_per_coded_sample;
>> +    FF_BAIL_ON_OVERFLOW(s, st->codecpar->channels && st->codecpar->bits_per_coded_sample > INT_MAX / st->codecpar->channels)
> 
> Shouldn't this go before the actual (potentially-overflowing) calculation is done?

It is.

>>     st->codecpar->block_align           = st->codecpar->channels *
>>                                           st->codecpar->bits_per_coded_sample;

This here is the problem.

Best regards,
Andreas