[FFmpeg-cvslog] avformat/vividas: Make len signed

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Nov 22 17:24:20 2020 +0100| [b29d351f972f801d0374ca8565cee398b8f69160] | committer: Michael Niedermayer

avformat/vividas: Make len signed

Fixes: out of array access
Fixes: 27424/clusterfuzz-testcase-minimized-ffmpeg_dem_VIVIDAS_fuzzer-5682070692823040

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b29d351f972f801d0374ca8565cee398b8f69160
---

 libavformat/vividas.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/vividas.c b/libavformat/vividas.c
index 46c66bf9a0..4adc125439 100644
--- a/libavformat/vividas.c
+++ b/libavformat/vividas.c
@@ -389,8 +389,8 @@ static int track_header(VividasDemuxContext *viv, AVFormatContext *s,  uint8_t *
             ffio_read_varlen(pb); // len_3
             num_data = avio_r8(pb);
             for (j = 0; j < num_data; j++) {
-                uint64_t len = ffio_read_varlen(pb);
-                if (len > INT_MAX/2 - xd_size) {
+                int64_t len = ffio_read_varlen(pb);
+                if (len < 0 || len > INT_MAX/2 - xd_size) {
                     return AVERROR_INVALIDDATA;
                 }
                 data_len[j] = len;