[FFmpeg-devel] [PATCH]lavc/alac: Avoid allocating huge memory blocks for malicious alac input.

[Paul B Mahol]

On 11/1/17, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
> 2017-11-01 15:40 GMT+01:00 Paul B Mahol <onemda at gmail.com>:
>> On 11/1/17, Carl Eugen Hoyos <ceffmpeg at gmail.com> wrote:
>>> Hi!
>>>
>>> It appears to me that the alac decoder can be used for DoS,
>>> the attached patch limits the maximum frame size to eight
>>> times the default value.
>>> (Higher values brake our encoder here.)
>>>
>>> Please comment and / or suggest another value, Carl Eugen
>>>
>>
>> So alac encoder can not handle bigger frames or what?
>>
>> Look at other alac encoders, what are their limit on frame size?
>
> I am not sure if it is enough to look on Apple's encoder, after
> all, their decoder looks exploitable (or maybe I miss something).
>
>> The limit you set is too low IMHO.
>
> Could you suggest a limit that's below the several-GB area?

I remmeber some lossless audio codecs can have very big frames, several MB.