[FFmpeg-devel] [PATCH] avcodec/hevcdec: Avoid only partly skiping duplicate first slices

[Michael Niedermayer]

Fixes: NULL pointer dereference and out of array access
Fixes: 13871/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5746167087890432
Fixes: 13845/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5650370728034304

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
 libavcodec/hevcdec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 86adab0ae1..4d149f4d9f 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -488,6 +488,9 @@ static int hls_slice_header(HEVCContext *s)
 
     // Coded parameters
     sh->first_slice_in_pic_flag = get_bits1(gb);
+    if (s->ref && sh->first_slice_in_pic_flag)
+        return 0; // This slice will be skiped later, do not corrupt state
+
     if ((IS_IDR(s) || IS_BLA(s)) && sh->first_slice_in_pic_flag) {
         s->seq_decode = (s->seq_decode + 1) & 0xff;
         s->max_ra     = INT_MAX;
-- 
2.21.0