[FFmpeg-cvslog] avcodec/ituh263dec: Check input for minimal frame size

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Tue Sep 24 00:42:04 2019 +0200| [7f0498ed461987b62bb97ff6463b4df108d60d78] | committer: Michael Niedermayer

avcodec/ituh263dec: Check input for minimal frame size

Fixes: Timeout (28sec -> 3sec)
Fixes: 17559/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_H263_fuzzer-5681050776240128

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=7f0498ed461987b62bb97ff6463b4df108d60d78
---

 libavcodec/ituh263dec.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/ituh263dec.c b/libavcodec/ituh263dec.c
index c37f872b3c..c1005b0994 100644
--- a/libavcodec/ituh263dec.c
+++ b/libavcodec/ituh263dec.c
@@ -1218,6 +1218,11 @@ int ff_h263_decode_picture_header(MpegEncContext *s)
     if ((ret = av_image_check_size(s->width, s->height, 0, s)) < 0)
         return ret;
 
+    if (!(s->avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)) {
+        if ((s->width * s->height / 256 / 8) > get_bits_left(&s->gb))
+            return AVERROR_INVALIDDATA;
+    }
+
     s->mb_width = (s->width  + 15) / 16;
     s->mb_height = (s->height  + 15) / 16;
     s->mb_num = s->mb_width * s->mb_height;