[FFmpeg-devel] [PATCH 10/10] Add av_image_alloc() and use it in avfilter_default_get_video_buffer().

[Stefano Sabatini]

On date Sunday 2010-11-14 20:22:06 +0100, Michael Niedermayer encoded:
> On Sun, Nov 14, 2010 at 12:26:40PM +0100, Stefano Sabatini wrote:
[...]
> > > > +int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
> > > > +                   int w, int h, enum PixelFormat pix_fmt, int align)
> > > > +{
> > > > +    int i, ret;
> > > > +    uint8_t *buf;
> > > > +
> > > > +    if ((ret = av_image_fill_linesizes(linesizes, pix_fmt, w)) < 0)
> > > > +        return ret;
> > > > +
> > > > +    for (i = 0; i < 4; i++)
> > > > +        linesizes[i] = FFALIGN(linesizes[i], align);
> > > > +
> > > > +    if ((ret = av_image_fill_pointers(pointers, pix_fmt, h, NULL, linesizes)) < 0)
> > > > +        return ret;
> > > 
> > > av_image_fill_pointers() does not seem to check w/h being valid and thus may
> > > be exploitable
> > 
> > Added av_image_check_size() check, I don't know if we should add to
> > the function params a log_offset and log_ctx, or simply disable
> > logging in all cases.
> > 
> > Also I see a function:
> > int av_image_get_size(int linesizes[4], int w, int h, enum PixFmt pix_fmt, int align);
> > 
> > may be useful as well.
> > -- 
> > FFmpeg = Fascinating and Faithless Moronic Plastic Excellent Ghost
> 
> >  libavcore/imgutils.c   |   29 +++++++++++++++++++++++++++++
> >  libavcore/imgutils.h   |   11 +++++++++++
> >  libavfilter/defaults.c |   17 +++--------------
> >  3 files changed, 43 insertions(+), 14 deletions(-)
> > 7b6e0f3d7edb8b14b71429036913e6574b187fa8  0002-Implement-av_image_alloc-and-use-it-in.patch
> > From 7f62492ee5a9ce930b37fd2f6d6e6d2dde2d8ccb Mon Sep 17 00:00:00 2001
> > From: Stefano Sabatini <stefano.sabatini-lala at poste.it>
> > Date: Sun, 7 Nov 2010 16:51:50 +0100
> > Subject: [PATCH 2/7] Implement av_image_alloc() and use it in
> >  avfilter_default_get_video_buffer().
> > 
> > ---
> >  libavcore/imgutils.c   |   29 +++++++++++++++++++++++++++++
> >  libavcore/imgutils.h   |   11 +++++++++++
> >  libavfilter/defaults.c |   17 +++--------------
> >  3 files changed, 43 insertions(+), 14 deletions(-)
> > 
> > diff --git a/libavcore/imgutils.c b/libavcore/imgutils.c
> > index 554639f..3f7df7a 100644
> > --- a/libavcore/imgutils.c
> > +++ b/libavcore/imgutils.c
> > @@ -161,6 +161,35 @@ int ff_set_systematic_pal2(uint32_t pal[256], enum PixelFormat pix_fmt)
> >      return 0;
> >  }
> >  
> > +int av_image_alloc(uint8_t *pointers[4], int linesizes[4],
> > +                   int w, int h, enum PixelFormat pix_fmt, int align)
> > +{
> > +    int i, ret;
> > +    uint8_t *buf;
> > +
> > +    if ((ret = av_image_check_size(w, h, 0, NULL)) < 0)
> > +        return ret;
> 
> thats the wrong place to check,
> av_image_fill_linesizes and av_image_fill_pointers still will fail if they are
> used with too large w/h i think

AFAIK the checks in av_image_check_size() should be enough, they're
even stricter than necessary for most pixel formats.
-- 
FFmpeg = Funny Fanciful Moronic Peaceful Earthshaking Game