[FFmpeg-devel] [PATCH 1/3] Support palette information for vobsub's stored as text in extradata

[Michael Niedermayer]

On Sun, Sep 11, 2011 at 11:27:43PM +0200, Joakim Plate wrote:
> 
> >>  }
> >>  
> >> +static int dvdsub_init(AVCodecContext *avctx)
> >> +{
> >> +    DVDSubContext *ctx = (DVDSubContext*) avctx->priv_data;
> >> +    char *data = avctx->extradata;
> >> +
> >> +    if (!avctx->extradata || !avctx->extradata_size)
> >> +        return 1;
> >> +
> >> +    data[avctx->extradata_size] = '\0';
> > 
> > this does not look safe
> 
> As far as I known, extradata must be padded, so writing one extra byte
> should always be safe. Then again, i'm not sure how well known it is that
> is should be. I suppose i could make a copy of it instead if we don't want
> to rely on padding being present.

thats half of the issue, the other half is that decoders shouldnt
write into their input which extradata is part of
please make a copy of it if this 0 byte is needed

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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