From 54655623a82632e7624714d7b2a3e039dc5faa7e Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 23 Mar 2019 20:55:08 +0100 Subject: [PATCH] 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 Signed-off-by: Michael Niedermayer --- 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;