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avcodec/hevc/hevcdec: Do not allow slices to depend on failed slices

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An alternative would be to leave the context unchanged on failure of hls_slice_header()

Fixes: out of array access
Fixes: NULL pointer dereference
Fixes: 69584/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5931086299856896
Fixes: 69724/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5104066422702080
Fixes: 70422/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HEVC_fuzzer-5908731129298944

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 5d9544cfb03d8597aa2b0037def3a4679949cec6)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2024-06-23 23:17:24 +02:00
parent 23af4eac80
commit 999720f8fd
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GPG Key ID: B18E8928B3948D64
1 changed files with 8 additions and 4 deletions
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12
libavcodec/hevcdec.c
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@ -572,6 +572,10 @@ static int hls_slice_header(HEVCContext *s)
if (s->ps.pps->dependent_slice_segments_enabled_flag)
sh->dependent_slice_segment_flag = get_bits1(gb);
if (sh->dependent_slice_segment_flag && !s->slice_initialized) {
av_log(s->avctx, AV_LOG_ERROR, "Independent slice segment missing.\n");
return AVERROR_INVALIDDATA;
}
slice_address_length = av_ceil_log2(s->ps.sps->ctb_width *
s->ps.sps->ctb_height);
@ -840,9 +844,6 @@ static int hls_slice_header(HEVCContext *s)
} else {
sh->slice_loop_filter_across_slices_enabled_flag = s->ps.pps->seq_loop_filter_across_slices_enabled_flag;
}
} else if (!s->slice_initialized) {
av_log(s->avctx, AV_LOG_ERROR, "Independent slice segment missing.\n");
return AVERROR_INVALIDDATA;
}
sh->num_entry_point_offsets = 0;
@ -2946,8 +2947,11 @@ static int decode_nal_unit(HEVCContext *s, const H2645NAL *nal)
case HEVC_NAL_RASL_N:
case HEVC_NAL_RASL_R:
ret = hls_slice_header(s);
if (ret < 0)
if (ret < 0) {
// hls_slice_header() does not cleanup on failure thus the state now is inconsistant so we cannot use it on depandant slices
s->slice_initialized = 0;
return ret;
}
if (ret == 1) {
ret = AVERROR_INVALIDDATA;
goto fail;