[FFmpeg-devel] [PATCH] avcodec/allcodecs: Provide empty codec_list in allcodecs when ossfuzz is used

[Michael Niedermayer]

On Mon, May 28, 2018 at 03:47:08AM +0200, Michael Niedermayer wrote:
> The last workaround is not sufficient to make oss fuzz work with the iterate API
> as it did not provide a FFmpeg that external libs can be linked to.
> 
> This patch does not fully restore the pre iterate functionality. My attempts to
> do this have so far failed.
> 
> The problem with this solution is that it renders the fuzzers virtual system
> ffmpeg (libs) non functional. Which differs from a real system compared to the
> virtual system tested by the fuzzer.
> It should theoretically not matter as the system ffmpeg wouldnt be used.
> But with more cases being fuzzed we likely will hit a case where a external
> lib is involved and it does matter ...
> 
> Working around this may be possible with weak symbols but so far my attempts
> failed
> 
> Alternatively multiple ffmpeg could be built, this becomes messy though
> quickly as they need to be all linked together. That is we need a FFmpeg
> that has the iterate API modified so it can work with the resources
> available to ossfuzz. And at the same time we need a ffmpeg that has
> its full functionality for any external libs which use ffmpeg and are
> used by ffmpeg.
> 
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/allcodecs.c    | 5 ++++-
>  tools/target_dec_fuzzer.c | 5 +----
>  2 files changed, 5 insertions(+), 5 deletions(-)

will apply

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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