On Sun, Jun 23, 2019 at 12:30:54AM +0200, Michael Niedermayer wrote:
> This checks the ham value much stricter and avoids hitting cases which cannot be reached
> with data from the libavformat demuxer.
>
> Fixes: out of array access
> Fixes: 15320/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5080476840099840
> Fixes: 15423/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_IFF_ILBM_fuzzer-5630765833912320
>
> 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/iff.c | 15 ++++++++++++---
> 1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/iff.c b/libavcodec/iff.c
> index b43bd507b3..b065bbe598 100644
> --- a/libavcodec/iff.c
> +++ b/libavcodec/iff.c
> @@ -280,6 +280,18 @@ static int extract_header(AVCodecContext *const avctx,
> for (i = 0; i < 16; i++)
> s->tvdc[i] = bytestream_get_be16(&buf);
>
> + if (s->ham) {
> + if (s->bpp > 8) {
> + av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u\n", s->ham);
> + s->ham = 0;
> + return AVERROR_INVALIDDATA;
> + } if (s->ham != (s->bpp > 6 ? 6 : 4)) {
> + av_log(avctx, AV_LOG_ERROR, "Invalid number of hold bits for HAM: %u, BPP: %u\n", s->ham, s->bpp);
> + s->ham = 0;
> + return AVERROR_INVALIDDATA;
> + }
> + }
i am curious why we need to reset ham = 0? otherwise patch okay.
patch 1 and 3 okay.
-- Peter
(A907 E02F A6E5 0CD2 34CD 20D2 6760 79C5 AC40 DD6B)
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