[FFmpeg-devel] [PATCH 2/4] avformat/vividas: Check av_xiphlacing() return value before use

[Michael Niedermayer]

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
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 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]);
-- 
2.23.0