[FFmpeg-cvslog] avformat/vividas: Check av_xiphlacing() return value before use

[Michael Niedermayer]

ffmpeg | branch: release/4.2 | Michael Niedermayer <michael at niedermayer.cc> | Wed Aug 21 23:05:21 2019 +0200| [da3e2efad6dc17793f49d08d102663228df63a69] | committer: Michael Niedermayer

avformat/vividas: Check av_xiphlacing() return value before use

Fixes: out of array access
Fixes: 16277/clusterfuzz-testcase-minimized-ffmpeg_DEMUXER_fuzzer-5696629440512000

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 5937f0550304e39be64ce41cc936634f1db54e5d)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=da3e2efad6dc17793f49d08d102663228df63a69
---

 libavformat/vividas.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/libavformat/vividas.c b/libavformat/vividas.c
index 0c33ca2da8..645e322b6e 100644
--- a/libavformat/vividas.c
+++ b/libavformat/vividas.c
@@ -392,8 +392,14 @@ static int track_header(VividasDemuxContext *viv, AVFormatContext *s,  uint8_t *
             p = st->codecpar->extradata;
             p[0] = 2;
 
-            for (j = 0; j < num_data - 1; j++)
-                offset += av_xiphlacing(&p[offset], data_len[j]);
+            for (j = 0; j < num_data - 1; j++) {
+                unsigned delta = av_xiphlacing(&p[offset], data_len[j]);
+                if (delta > data_len[j]) {
+                    av_free(pb);
+                    return AVERROR_INVALIDDATA;
+                }
+                offset += delta;
+            }
 
             for (j = 0; j < num_data; j++) {
                 int ret = avio_read(pb, &p[offset], data_len[j]);