[FFmpeg-devel] [PATCH] webp: avoid trying to decode trailing junk in bitstreams

[Michael Niedermayer]

On Wed, Sep 04, 2019 at 07:43:15AM +0200, Pascal Massimino wrote:
> Hi,
> 
> this patch break the decoding loop when invalid webp chunk is encountered.
> We can still have a valid frame ready to be returned (*got_frame = 1).
> 

> fixes trac #8107 (/#7612)

These bug references should be in the commit message


> 
> skal/

>  webp.c |    7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 2d80b062adade6044f64a00838b55f9427cc1f73  0001-webp-fix-decoding-for-trailing-junk.patch
> From 9edff4f9812fad7f605bdc12954f82a8745a25ee Mon Sep 17 00:00:00 2001
> From: Pascal Massimino <pascal.massimino at gmail.com>
> Date: Wed, 28 Aug 2019 09:41:42 +0200
> Subject: [PATCH] webp: fix decoding for trailing junk
> 
> some bitstream have trailing junk, despite being valid webp data.
> In case of apparent error, abort the loop and let *got_frame
> decide whether this is an error or not.
> Another possibility would be turning the loop into:
>     while (!*got_frame) {...}

what is that trailing junk ?

i would guess its not a known chunk but rather hits the default
is that just a bunch of 0 or 0xFF bytes ?
detecting before we read into the end feels more robust if
we can simply detect the "junk"

thanks

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 181 bytes
Desc: not available
URL: <http://ffmpeg.org/pipermail/ffmpeg-devel/attachments/20190905/07da9c10/attachment.sig>