[FFmpeg-cvslog] avformat/mxfdec: Fix Sign error in mxf_read_primer_pack()

[孙浩(晓黑)]

ffmpeg | branch: master | 孙浩(晓黑) <tony.sh at alibaba-inc.com> | Tue Aug 29 23:59:21 2017 +0200| [9d00fb9d70ee8c0cc7002b89318c5be00f1bbdad] | committer: Michael Niedermayer

avformat/mxfdec: Fix Sign error in mxf_read_primer_pack()

Fixes: 20170829B.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>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=9d00fb9d70ee8c0cc7002b89318c5be00f1bbdad
---

 libavformat/mxfdec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavformat/mxfdec.c b/libavformat/mxfdec.c
index 6adb77d81f..91731a7533 100644
--- a/libavformat/mxfdec.c
+++ b/libavformat/mxfdec.c
@@ -500,7 +500,7 @@ static int mxf_read_primer_pack(void *arg, AVIOContext *pb, int tag, int size, U
         avpriv_request_sample(pb, "Primer pack item length %d", item_len);
         return AVERROR_PATCHWELCOME;
     }
-    if (item_num > 65536) {
+    if (item_num > 65536 || item_num < 0) {
         av_log(mxf->fc, AV_LOG_ERROR, "item_num %d is too large\n", item_num);
         return AVERROR_INVALIDDATA;
     }