[FFmpeg-cvslog] avformat/nsvdec: Fix DoS due to lack of eof check in nsvs_file_offset loop.

[孙浩(晓黑)]

ffmpeg | branch: release/3.3 | 孙浩(晓黑) <tony.sh at alibaba-inc.com> | Tue Aug 29 23:59:21 2017 +0200| [e6a8d110d7e8e938913a0a85ca933b415f8ed24d] | committer: Michael Niedermayer

avformat/nsvdec: Fix DoS due to lack of eof check in nsvs_file_offset loop.

Fixes: 20170829.nsv

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 c24bcb553650b91e9eff15ef6e54ca73de2453b7)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e6a8d110d7e8e938913a0a85ca933b415f8ed24d
---

 libavformat/nsvdec.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/libavformat/nsvdec.c b/libavformat/nsvdec.c
index c6ddb67bbd..d8ce656817 100644
--- a/libavformat/nsvdec.c
+++ b/libavformat/nsvdec.c
@@ -335,8 +335,11 @@ static int nsv_parse_NSVf_header(AVFormatContext *s)
         if (!nsv->nsvs_file_offset)
             return AVERROR(ENOMEM);
 
-        for(i=0;i<table_entries_used;i++)
+        for(i=0;i<table_entries_used;i++) {
+            if (avio_feof(pb))
+                return AVERROR_INVALIDDATA;
             nsv->nsvs_file_offset[i] = avio_rl32(pb) + size;
+        }
 
         if(table_entries > table_entries_used &&
            avio_rl32(pb) == MKTAG('T','O','C','2')) {