[vlc-devel] [PATCH] es_out: merge es->i_id with es->fmt.i_id

[Francois Cartegnie]

Le 17/08/2018 à 15:07, Thomas Guillem a écrit :
> 
> On Fri, Aug 17, 2018, at 15:00, Francois Cartegnie wrote:
>> Le 17/08/2018 à 14:43, Thomas Guillem a écrit :
>>> Should we identify an ES track with a uint64_t that is always
>>> incremented from the es_out ?
>>> This will allow to either:
>>>  - select a track via the original fmt.i_id (for advanced users via
>>>    params/libvlc only, this doesn't prevent es id collision) - select a track with this unique uint64_t id (this will be the id
>>>    propagated via input events).
>>
>> I don't see why an uint32_t counter would be less prone to overflow than
>> uin64_t in our use case
> 
> If you end up creating more than 4.2949673E9 ES tracks, I think something is wrong (sample is an exploit?) and the input should be terminated right away.
> 
> Could you propose other solutions ?

I can ES add/del UINT64_MAX. Larger counter won't solve anything.

You can't track usable ids unless you allocate UINTxx_MAX bits to
reference id usage, and add a worth case time of that number of bytes - 1.

Someone considered there was no issue in refcounters overflows because
it was unlikely to be ever reached.

-- 
Francois Cartegnie
VideoLAN - VLC Developer