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

Message ID 20220918171410.31835-10-michael@niedermayer.cc
State New
Headers show
Series [FFmpeg-devel,01/13] avformat/flvdec: Use 64bit for sum_flv_tag_size | expand

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Commit Message

Michael Niedermayer Sept. 18, 2022, 5:14 p.m. UTC
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(-)

Comments

Anton Khirnov Sept. 22, 2022, 1:18 p.m. UTC | #1
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.
Michael Niedermayer Sept. 22, 2022, 4:12 p.m. UTC | #2
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

[...]
diff mbox series

Patch

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;
 
         pb = viv->sb_pb;
         ret = av_get_packet(pb, pkt, size);