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

[孙浩 and 张洪亮(望初)]

ffmpeg | branch: release/3.0 | 孙浩 and 张洪亮(望初) <tony.sh and wangchu.zhl at alibaba-inc.com> | Fri Aug 25 12:37:25 2017 +0200| [39ddbd204aad0e1e1988b108a507f3c608b0129b] | committer: Michael Niedermayer

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

Fixes: loop.asf

Found-by: Xiaohei and Wangchu from Alibaba Security Team
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 7f9ec5593e04827249e7aeb466da06a98a0d7329)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=39ddbd204aad0e1e1988b108a507f3c608b0129b
---

 libavformat/asfdec_f.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavformat/asfdec_f.c b/libavformat/asfdec_f.c
index 3ee0fcd473..42f00259a6 100644
--- a/libavformat/asfdec_f.c
+++ b/libavformat/asfdec_f.c
@@ -749,13 +749,15 @@ static int asf_read_marker(AVFormatContext *s, int64_t size)
     count = avio_rl32(pb);    // markers count
     avio_rl16(pb);            // reserved 2 bytes
     name_len = avio_rl16(pb); // name length
-    for (i = 0; i < name_len; i++)
-        avio_r8(pb); // skip the name
+    avio_skip(pb, name_len);
 
     for (i = 0; i < count; i++) {
         int64_t pres_time;
         int name_len;
 
+        if (avio_feof(pb))
+            return AVERROR_INVALIDDATA;
+
         avio_rl64(pb);             // offset, 8 bytes
         pres_time = avio_rl64(pb); // presentation time
         pres_time -= asf->hdr.preroll * 10000;