[FFmpeg-cvslog] avcodec/hevcdec: Avoid only partly skiping duplicate first slices
Michael Niedermayer
git at videolan.org
Wed Mar 27 09:45:17 EET 2019
ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sat Mar 23 20:55:08 2019 +0100| [54655623a82632e7624714d7b2a3e039dc5faa7e] | committer: Michael Niedermayer
avcodec/hevcdec: Avoid only partly skiping duplicate first slices
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
This also fixes the return code for explode mode
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: James Almer <jamrial at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=54655623a82632e7624714d7b2a3e039dc5faa7e
---
libavcodec/hevcdec.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
index 86adab0ae1..857c10dd12 100644
--- a/libavcodec/hevcdec.c
+++ b/libavcodec/hevcdec.c
@@ -488,6 +488,11 @@ 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) {
+ av_log(s->avctx, AV_LOG_ERROR, "Two slices reporting being the first in the same frame.\n");
+ return 1; // 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;
@@ -2918,6 +2923,11 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
ret = hls_slice_header(s);
if (ret < 0)
return ret;
+ if (ret == 1) {
+ ret = AVERROR_INVALIDDATA;
+ goto fail;
+ }
+
if (
(s->avctx->skip_frame >= AVDISCARD_BIDIR && s->sh.slice_type == HEVC_SLICE_B) ||
@@ -2927,10 +2937,6 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
}
if (s->sh.first_slice_in_pic_flag) {
- if (s->ref) {
- av_log(s->avctx, AV_LOG_ERROR, "Two slices reporting being the first in the same frame.\n");
- goto fail;
- }
if (s->max_ra == INT_MAX) {
if (s->nal_unit_type == HEVC_NAL_CRA_NUT || IS_BLA(s)) {
s->max_ra = s->poc;
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