[FFmpeg-cvslog] avformat/mxfdec: Fix DoS issues in mxf_read_index_entry_array()

[孙浩(晓黑)]

ffmpeg | branch: release/3.0 | 孙浩(晓黑) <tony.sh at alibaba-inc.com> | Tue Aug 29 23:59:21 2017 +0200| [74c067e95572dd4bfb069123f44d68b8a12e1991] | committer: Michael Niedermayer

avformat/mxfdec: Fix DoS issues in mxf_read_index_entry_array()

Fixes: 20170829A.mxf

Co-Author: 张洪亮(望初)" <wangchu.zhl at alibaba-inc.com>
Found-by: Xiaohei and Wangchu from Alibaba Security Team
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 900f39692ca0337a98a7cf047e4e2611071810c2)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=74c067e95572dd4bfb069123f44d68b8a12e1991
---

 libavformat/mxfdec.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index 173a769ada..ae518f9a88 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -887,6 +887,8 @@ static int mxf_read_index_entry_array(AVIOContext *pb, MXFIndexTableSegment *seg
     segment->nb_index_entries = avio_rb32(pb);
 
     length = avio_rb32(pb);
+    if(segment->nb_index_entries && length < 11)
+        return AVERROR_INVALIDDATA;
 
     if (!(segment->temporal_offset_entries=av_calloc(segment->nb_index_entries, sizeof(*segment->temporal_offset_entries))) ||
         !(segment->flag_entries          = av_calloc(segment->nb_index_entries, sizeof(*segment->flag_entries))) ||
@@ -897,6 +899,8 @@ static int mxf_read_index_entry_array(AVIOContext *pb, MXFIndexTableSegment *seg
     }
 
     for (i = 0; i < segment->nb_index_entries; i++) {
+        if(avio_feof(pb))
+            return AVERROR_INVALIDDATA;
         segment->temporal_offset_entries[i] = avio_r8(pb);
         avio_r8(pb);                                        /* KeyFrameOffset */
         segment->flag_entries[i] = avio_r8(pb);