[FFmpeg-devel] [PATCH 1/2] MxPEG decoder

[Anatoly Nenashev]

On 29.11.2010 16:12, Anatoly Nenashev wrote:
> On 25.11.2010 18:26, Michael Niedermayer wrote:
>> On Mon, Nov 08, 2010 at 01:40:39PM +0300, Anatoly Nenashev wrote:
>>> [...]
>>> I think I've found a solution for this issue. If input packet doesn't
>>> contain SOF data then the new picture is allocated from
>>> reference_picture which is initiated at decode_frame end. Thus
>>> reference_picture is always good. For more details see attachment.
>>
>> the issue i described has not been fixed
>> a invalid SOF still can lead to inconsistant values and your code 
>> still naively
>> sets got_picture=1 indicating a valid SOF even if that is not so.
>>
>> Fundamentally i think the problem is that you write the code while 
>> ignoring
>> security aspects entirely and expect review to find security issues.
>> You should make sure your code is secure and no crafted input no 
>> matter how
>> evil and malformed can lead to any crash or exploit before you submit 
>> your
>> code.
>>
>>
>> [...]
>>
>
> I've reimplemented decoder to be more secure. There is additional flag 
> named "got_sof_data" which shows that SOF data is succesfully parsed.
> Also ugly picture reallocation removed.
>
Add dimensions check for current and reference picture.
Patch tested under valgrind and on trashed stream.
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