[FFmpeg-devel] [PATCH 2/5] libavcodec/mpeg12dec: Check input for minimal frame size

[Michael Niedermayer]

Fixes: Timeout (35sec -> 6sec)
Fixes: 16901/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MPEGVIDEO_fuzzer-5729024726269952

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/mpeg12dec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/mpeg12dec.c b/libavcodec/mpeg12dec.c
index 83e537884b..ecfc2a440d 100644
--- a/libavcodec/mpeg12dec.c
+++ b/libavcodec/mpeg12dec.c
@@ -1596,6 +1596,9 @@ static int mpeg_field_start(MpegEncContext *s, const uint8_t *buf, int buf_size)
     Mpeg1Context *s1      = (Mpeg1Context *) s;
     int ret;
 
+    if (s->mb_width * s->mb_height * 11LL / (33 * 2 * 8) > buf_size)
+        return AVERROR_INVALIDDATA;
+
     /* start frame decoding */
     if (s->first_field || s->picture_structure == PICT_FRAME) {
         AVFrameSideData *pan_scan;
-- 
2.23.0