[FFmpeg-devel] [PATCH] avcodec/speexdec: Consider mode in frame size check

[FFmpeg-devel] [PATCH] avcodec/speexdec: Consider mode in frame size check

[Michael Niedermayer]

No speex samples with non default frame sizes are known (to me)
the official speexenc seems to only generate the 3 default ones.
Thus it may be that the fuzzer samples where the first non default
values encountered by the decoder.
Possibly the "<" should be "!="

If someone has a valid speex file with non default frame sizes that
would be interesting!

Fixes: out of array access
Fixes: 42821/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SPEEX_fuzzer-5640695772217344

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
 libavcodec/speexdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/speexdec.c b/libavcodec/speexdec.c
index 1c33607db27..dcbdf5e010a 100644
--- a/libavcodec/speexdec.c
+++ b/libavcodec/speexdec.c
@@ -1419,7 +1419,7 @@ static int parse_speex_extradata(AVCodecContext *avctx,
         return AVERROR_INVALIDDATA;
     s->bitrate = bytestream_get_le32(&buf);
     s->frame_size = bytestream_get_le32(&buf);
-    if (s->frame_size < NB_FRAME_SIZE)
+    if (s->frame_size < NB_FRAME_SIZE << s->mode)
         return AVERROR_INVALIDDATA;
     s->vbr = bytestream_get_le32(&buf);
     s->frames_per_packet = bytestream_get_le32(&buf);
-- 
2.17.1

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Re: [FFmpeg-devel] [PATCH] avcodec/speexdec: Consider mode in frame size check

[Michael Niedermayer]

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On Sun, Dec 26, 2021 at 02:37:23PM +0100, Michael Niedermayer wrote:
> No speex samples with non default frame sizes are known (to me)
> the official speexenc seems to only generate the 3 default ones.
> Thus it may be that the fuzzer samples where the first non default
> values encountered by the decoder.
> Possibly the "<" should be "!="
> 
> If someone has a valid speex file with non default frame sizes that
> would be interesting!
> 
> Fixes: out of array access
> Fixes: 42821/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_SPEEX_fuzzer-5640695772217344
> 
> Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/speexdec.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

will apply

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you fake or manipulate statistics in a paper in physics you will never
get a job again.
If you fake or manipulate statistics in a paper in medicin you will get
a job for life at the pharma industry.

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