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[FFmpeg-devel] avcodec/notchlc: Check available space for luma block code

Message ID 20200912164330.25807-1-michael@niedermayer.cc
State New
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Series [FFmpeg-devel] avcodec/notchlc: Check available space for luma block code
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Commit Message

Michael Niedermayer Sept. 12, 2020, 4:43 p.m. UTC
Fixes: Timeout (too long -> 2sec)
Fixes: 25439/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_NOTCHLC_fuzzer-5688211127664640

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/notchlc.c | 3 +++
 1 file changed, 3 insertions(+)

Comments

Paul B Mahol Sept. 12, 2020, 10:39 p.m. UTC | #1
On Sat, Sep 12, 2020 at 06:43:30PM +0200, Michael Niedermayer wrote:
> Fixes: Timeout (too long -> 2sec)
> Fixes: 25439/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_NOTCHLC_fuzzer-5688211127664640
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/notchlc.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/libavcodec/notchlc.c b/libavcodec/notchlc.c
> index 3f7079da70..e7e69b0c21 100644
> --- a/libavcodec/notchlc.c
> +++ b/libavcodec/notchlc.c
> @@ -229,6 +229,9 @@ static int decode_blocks(AVCodecContext *avctx, AVFrame *p, ThreadFrame *frame,
>      bytestream2_seek(&rgb, s->y_data_row_offsets, SEEK_SET);
>      bytestream2_seek(gb, s->y_control_data_offset, SEEK_SET);
>  
> +    if ((avctx->height + 3) / 4 * ((avctx->width + 3) / 4) * 4 > bytestream2_get_bytes_left(gb))
> +        return AVERROR_INVALIDDATA;
> +
>      dsty = (uint16_t *)p->data[0];
>      dsta = (uint16_t *)p->data[3];
>      ylinesize = p->linesize[0] / 2;
> -- 
> 2.17.1

Is this correct at all?

If you do not like timeouts than get smaller samples or reduce dimensions of accepted files.
Michael Niedermayer Sept. 13, 2020, 1:53 p.m. UTC | #2
On Sun, Sep 13, 2020 at 12:39:34AM +0200, Paul B Mahol wrote:
> On Sat, Sep 12, 2020 at 06:43:30PM +0200, Michael Niedermayer wrote:
> > Fixes: Timeout (too long -> 2sec)
> > Fixes: 25439/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_NOTCHLC_fuzzer-5688211127664640
> > 
> > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > ---
> >  libavcodec/notchlc.c | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/libavcodec/notchlc.c b/libavcodec/notchlc.c
> > index 3f7079da70..e7e69b0c21 100644
> > --- a/libavcodec/notchlc.c
> > +++ b/libavcodec/notchlc.c
> > @@ -229,6 +229,9 @@ static int decode_blocks(AVCodecContext *avctx, AVFrame *p, ThreadFrame *frame,
> >      bytestream2_seek(&rgb, s->y_data_row_offsets, SEEK_SET);
> >      bytestream2_seek(gb, s->y_control_data_offset, SEEK_SET);
> >  
> > +    if ((avctx->height + 3) / 4 * ((avctx->width + 3) / 4) * 4 > bytestream2_get_bytes_left(gb))
> > +        return AVERROR_INVALIDDATA;
> > +
> >      dsty = (uint16_t *)p->data[0];
> >      dsta = (uint16_t *)p->data[3];
> >      ylinesize = p->linesize[0] / 2;
> > -- 
> > 2.17.1
> 
> Is this correct at all?

Its the amount that is read from gb in the next loop just below the added 
check

thx

> 
> If you do not like timeouts than get smaller samples or reduce dimensions of accepted files.
> _______________________________________________
> 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".
Paul B Mahol Sept. 13, 2020, 1:59 p.m. UTC | #3
On Sun, Sep 13, 2020 at 03:53:18PM +0200, Michael Niedermayer wrote:
> On Sun, Sep 13, 2020 at 12:39:34AM +0200, Paul B Mahol wrote:
> > On Sat, Sep 12, 2020 at 06:43:30PM +0200, Michael Niedermayer wrote:
> > > Fixes: Timeout (too long -> 2sec)
> > > Fixes: 25439/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_NOTCHLC_fuzzer-5688211127664640
> > > 
> > > Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> > > Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> > > ---
> > >  libavcodec/notchlc.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > > 
> > > diff --git a/libavcodec/notchlc.c b/libavcodec/notchlc.c
> > > index 3f7079da70..e7e69b0c21 100644
> > > --- a/libavcodec/notchlc.c
> > > +++ b/libavcodec/notchlc.c
> > > @@ -229,6 +229,9 @@ static int decode_blocks(AVCodecContext *avctx, AVFrame *p, ThreadFrame *frame,
> > >      bytestream2_seek(&rgb, s->y_data_row_offsets, SEEK_SET);
> > >      bytestream2_seek(gb, s->y_control_data_offset, SEEK_SET);
> > >  
> > > +    if ((avctx->height + 3) / 4 * ((avctx->width + 3) / 4) * 4 > bytestream2_get_bytes_left(gb))
> > > +        return AVERROR_INVALIDDATA;
> > > +
> > >      dsty = (uint16_t *)p->data[0];
> > >      dsta = (uint16_t *)p->data[3];
> > >      ylinesize = p->linesize[0] / 2;
> > > -- 
> > > 2.17.1
> > 
> > Is this correct at all?
> 
> Its the amount that is read from gb in the next loop just below the added 
> check

There is also alpha handling code. Also I dislike completely this reverse style, bytestream2.. should be first.

With that fixed and actually tested that it does not break decoding it should be fine.

> 
> thx
> 
> > 
> > If you do not like timeouts than get smaller samples or reduce dimensions of accepted files.
> > _______________________________________________
> > 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".
> 
> -- 
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
> 
> There will always be a question for which you do not know the correct answer.



> _______________________________________________
> 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".
diff mbox series

Patch

diff --git a/libavcodec/notchlc.c b/libavcodec/notchlc.c
index 3f7079da70..e7e69b0c21 100644
--- a/libavcodec/notchlc.c
+++ b/libavcodec/notchlc.c
@@ -229,6 +229,9 @@  static int decode_blocks(AVCodecContext *avctx, AVFrame *p, ThreadFrame *frame,
     bytestream2_seek(&rgb, s->y_data_row_offsets, SEEK_SET);
     bytestream2_seek(gb, s->y_control_data_offset, SEEK_SET);
 
+    if ((avctx->height + 3) / 4 * ((avctx->width + 3) / 4) * 4 > bytestream2_get_bytes_left(gb))
+        return AVERROR_INVALIDDATA;
+
     dsty = (uint16_t *)p->data[0];
     dsta = (uint16_t *)p->data[3];
     ylinesize = p->linesize[0] / 2;