Re: [FFmpeg-devel] [PATCH 10/13] avformat/vividas: Check packet size

From: Michael Niedermayer <michael@niedermayer.cc>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: Re: [FFmpeg-devel] [PATCH 10/13] avformat/vividas: Check packet size
Date: Thu, 22 Sep 2022 18:12:32 +0200
Message-ID: <20220922161232.GL6583@pb2> (raw)
In-Reply-To: <166385270026.3205.1761442577153286949@lain.khirnov.net>

[-- Attachment #1.1: Type: text/plain, Size: 1754 bytes --]

On Thu, Sep 22, 2022 at 03:18:20PM +0200, Anton Khirnov wrote:
> Quoting Michael Niedermayer (2022-09-18 19:14:07)
> > Fixes: signed integer overflow: 119760682 - -2084600173 cannot be represented in type 'int'
> > Fixes: 50993/clusterfuzz-testcase-minimized-ffmpeg_dem_VIVIDAS_fuzzer-6745781167587328
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavformat/vividas.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/libavformat/vividas.c b/libavformat/vividas.c
> > index e9954f73ed0..22f61db7576 100644
> > --- a/libavformat/vividas.c
> > +++ b/libavformat/vividas.c
> > @@ -643,7 +643,9 @@ static int viv_read_packet(AVFormatContext *s,
> >  
> >      if (viv->current_audio_subpacket < viv->n_audio_subpackets) {
> >          AVStream *astream;
> > -        int size = viv->audio_subpackets[viv->current_audio_subpacket+1].start - viv->audio_subpackets[viv->current_audio_subpacket].start;
> > +        int64_t size = viv->audio_subpackets[viv->current_audio_subpacket+1].start - (int64_t)viv->audio_subpackets[viv->current_audio_subpacket].start;
> > +        if (size < 0 || size != (int)size)
> > +            return AVERROR_INVALIDDATA;
> 
> These values should be checked in the loop where they are set.

ok but then we fail before the actual problem is encountered
i will send a patch doing that

thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No human being will ever know the Truth, for even if they happen to say it
by chance, they would not even known they had done so. -- Xenophanes

[-- Attachment #1.2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]

[-- Attachment #2: Type: text/plain, Size: 251 bytes --]

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".