[FFmpeg-devel] [PATCH 2/9] 4xm: prevent overflow during block alignment calculation

[Andreas Cadhalpun]

On 06.01.2017 20:58, Ronald S. Bultje wrote:
> Hi,
> 
> On Fri, Jan 6, 2017 at 2:47 PM, 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 2758b69d29..45949c4e97 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_RETURN_ON_OVERFLOW(s, st->codecpar->channels &&
>> st->codecpar->bits_per_coded_sample > INT_MAX / st->codecpar->channels)
>>      st->codecpar->block_align           = st->codecpar->channels *
>>                                            st->codecpar->bits_per_coded_
>> sample;
>>
>> --
>> 2.11.0
> 
> 
> To an innocent reader (who doesn't know/care about SIGFPE), this might look
> like channels = 0 is an actual valid decoder condition that is explicitly
> handled here.

Actually this function errors out earlier if channels is zero, so I've removed
this pointless additional check. Updated patch is attached.

Best regards,
Andreas


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