[FFmpeg-cvslog] avformat/vpk: Check offset for validity

[Michael Niedermayer]

ffmpeg | branch: release/4.1 | Michael Niedermayer <michael at niedermayer.cc> | Thu Jun  6 23:17:18 2019 +0200| [e73ef454e89dcce85fbc8c12ccb5c6b73c7a343c] | committer: Michael Niedermayer

avformat/vpk: Check offset for validity

Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit aa003019ab9ec5ef7e7b3ff9d6262d3472b427eb)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e73ef454e89dcce85fbc8c12ccb5c6b73c7a343c
---

 libavformat/vpk.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavformat/vpk.c b/libavformat/vpk.c
index 0a058b9d7f..64a0d56926 100644
--- a/libavformat/vpk.c
+++ b/libavformat/vpk.c
@@ -66,6 +66,9 @@ static int vpk_read_header(AVFormatContext *s)
         return AVERROR_INVALIDDATA;
     vpk->block_count       = (st->duration + (samples_per_block - 1)) / samples_per_block;
     vpk->last_block_size   = (st->duration % samples_per_block) * 16 * st->codecpar->channels / 28;
+
+    if (offset < avio_tell(s->pb))
+        return AVERROR_INVALIDDATA;
     avio_skip(s->pb, offset - avio_tell(s->pb));
     avpriv_set_pts_info(st, 64, 1, st->codecpar->sample_rate);