[FFmpeg-cvslog] asfdec: check for too small size in asf_read_unknown

[Andreas Cadhalpun]

ffmpeg | branch: master | Andreas Cadhalpun <andreas.cadhalpun at googlemail.com> | Wed Jan  6 20:59:58 2016 +0100| [bf50607ab76157ba251a01f5baa5cf67b23b2ee9] | committer: Luca Barbato

asfdec: check for too small size in asf_read_unknown

This fixes infinite loops due to seeking back.

Signed-off-by: Alexandra Hájková <alexandra at khirnov.net>
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bf50607ab76157ba251a01f5baa5cf67b23b2ee9
---

 libavformat/asfdec.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavformat/asfdec.c b/libavformat/asfdec.c
index aef61bb..cbab9a2 100644
--- a/libavformat/asfdec.c
+++ b/libavformat/asfdec.c
@@ -190,8 +190,13 @@ static int asf_read_unknown(AVFormatContext *s, const GUIDParseTable *g)
         if ((ret = detect_unknown_subobject(s, asf->unknown_offset,
                                             asf->unknown_size)) < 0)
             return ret;
-    } else
+    } else {
+        if (size < 24) {
+            av_log(s, AV_LOG_ERROR, "Too small size %"PRIu64" (< 24).\n", size);
+            return AVERROR_INVALIDDATA;
+        }
         avio_skip(pb, size - 24);
+    }
 
     return 0;
 }