[FFmpeg-devel] [PATCH 4/5] avfilter/formats: proper error handling in ff_set_common_*() functions

[Clément Bœsch]

On Sun, Mar 15, 2015 at 03:11:14PM +0100, Clément Bœsch wrote:
> On Sun, Mar 15, 2015 at 03:07:16PM +0100, Stefano Sabatini wrote:
> > On date Sunday 2015-03-15 14:24:29 +0100, Clément Bœsch encoded:
> > > ---
> > >  libavfilter/formats.c | 45 ++++++++++++++++++++++++++++++++-------------
> > >  libavfilter/formats.h | 10 +++++-----
> > >  2 files changed, 37 insertions(+), 18 deletions(-)
> > > 
> > > diff --git a/libavfilter/formats.c b/libavfilter/formats.c
> > > index 6393416..4f9773b 100644
> > > --- a/libavfilter/formats.c
> > > +++ b/libavfilter/formats.c
> > > @@ -401,7 +401,12 @@ AVFilterChannelLayouts *ff_all_channel_counts(void)
> > >  }
> > >  
> > >  #define FORMATS_REF(f, ref)                                                     \
> > > -    void *tmp = av_realloc_array(f->refs, sizeof(*f->refs), f->refcount + 1);   \
> > > +    void *tmp;                                                                  \
> > > +                                                                                \
> > > +    if (!ref)                                                                   \
> > > +        return AVERROR_BUG;                                                     \
> > 
> > I'd prefer to crash or assert here, assuming the function doesn't
> > assume NULL, same below.
> > 
> 
> In the current state, these functions could be called with a NULL
> parameter. Random examples:
> 
> libavfilter/src_movie.c: ff_formats_ref(ff_make_format_list(list), &outlink->in_formats);
> libavfilter/src_movie.c: ff_formats_ref(ff_make_format_list(list), &outlink->in_samplerates);
> libavfilter/vf_extractplanes.c: ff_formats_ref(ff_make_format_list(in_pixfmts), &ctx->inputs[0]->out_formats);
> libavfilter/vf_extractplanes.c: ff_formats_ref(ff_make_format_list(out_pixfmts), &ctx->outputs[i]->in_formats);
> 
> So I'd better not do that.
> 
> > (Unrelated note: "bug" is a silly term, "defect" is more proper - I'm
> > with Dijkstra here).
> > 

To elaborate on this, the bug here is referring to an allocation check not
done in the caller (there are many currently since I'm just introducing
the error handling).

-- 
Clément B.
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