[FFmpeg-cvslog] avformat/mvdec: Fix DoS due to lack of eof check

[Michael Niedermayer]

ffmpeg | branch: release/3.0 | Michael Niedermayer <michael at niedermayer.cc> | Fri Aug 25 01:15:30 2017 +0200| [9a73a776816b359cc5befe2ddaa7edef22c4f353] | committer: Michael Niedermayer

avformat/mvdec: Fix DoS due to lack of eof check

Fixes: loop.mv

Found-by: Xiaohei and Wangchu from Alibaba Security Team
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 4f05e2e2dc1a89f38cd9f0960a6561083d714f1e)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9a73a776816b359cc5befe2ddaa7edef22c4f353
---

 libavformat/mvdec.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavformat/mvdec.c b/libavformat/mvdec.c
index 7aa6452f66..e3feda6687 100644
--- a/libavformat/mvdec.c
+++ b/libavformat/mvdec.c
@@ -338,6 +338,8 @@ static int mv_read_header(AVFormatContext *avctx)
             uint32_t pos   = avio_rb32(pb);
             uint32_t asize = avio_rb32(pb);
             uint32_t vsize = avio_rb32(pb);
+            if (avio_feof(pb))
+                return AVERROR_INVALIDDATA;
             avio_skip(pb, 8);
             av_add_index_entry(ast, pos, timestamp, asize, 0, AVINDEX_KEYFRAME);
             av_add_index_entry(vst, pos + asize, i, vsize, 0, AVINDEX_KEYFRAME);