[FFmpeg-devel] [PATCH] Fix off-by-few crasher in ff_h2645_extract_rbsp function

[Carl Eugen Hoyos]

2017-03-07 12:30 GMT+01:00 Michał Krasowski <mkrasowski at opera.com>:

>>> There are few things that are still not clear to me:
>>> * Why is the 32 bit padding used when the doc says that
>>>   64 bit offset may also be needed?
>>
>>I don't understand your question but you may want to
>>send an update for this sentence.
>
> I mean that the doc says:
>> * This is mainly needed because some optimized bitstream readers read
>> * 32 or 64 bit at once and could read over the end.<br>
> So in case of reading 64 bits at once, may it be the case that 8 bytes padding
> is needed?

(No, 32 bytes are - curently - always needed, see Hendrik's email.)

The relevant line is the definition of AV_INPUT_BUFFER_PADDING_SIZE

Your code should look similar to:
uint8_t *ptr = av_malloc(buffer_size + AV_INPUT_BUFFER_PADDING_SIZE);
And a zero-initialization of the padding.

Carl Eugen