[FFmpeg-devel] [PATCH 4/4] avcodec/vp3: Check width to avoid assertion failure
Andreas Rheinhardt
andreas.rheinhardt at outlook.com
Mon Mar 27 12:59:44 EEST 2023
Michael Niedermayer:
> Fixes: Assertion failure on x86-32
> Fixes: 39641/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_THEORA_fuzzer-5925660741206016
>
> 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/vp3.c | 8 +++++++-
> 1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/libavcodec/vp3.c b/libavcodec/vp3.c
> index 9660def675f..22348559461 100644
> --- a/libavcodec/vp3.c
> +++ b/libavcodec/vp3.c
> @@ -2353,6 +2353,8 @@ static av_cold int vp3_decode_init(AVCodecContext *avctx)
> s->avctx = avctx;
> s->width = FFALIGN(avctx->coded_width, 16);
> s->height = FFALIGN(avctx->coded_height, 16);
> + if (s->width < 18)
> + return AVERROR_PATCHWELCOME;
> if (avctx->codec_id != AV_CODEC_ID_THEORA)
> avctx->pix_fmt = AV_PIX_FMT_YUV420P;
> avctx->chroma_sample_location = AVCHROMA_LOC_CENTER;
> @@ -2919,7 +2921,9 @@ static int theora_decode_header(AVCodecContext *avctx, GetBitContext *gb)
> /* sanity check */
> if (av_image_check_size(visible_width, visible_height, 0, avctx) < 0 ||
> visible_width + offset_x > s->width ||
> - visible_height + offset_y > s->height) {
> + visible_height + offset_y > s->height ||
> + visible_width < 18
> + ) {
> av_log(avctx, AV_LOG_ERROR,
> "Invalid frame dimensions - w:%d h:%d x:%d y:%d (%dx%d).\n",
> visible_width, visible_height, offset_x, offset_y,
> @@ -2965,6 +2969,8 @@ static int theora_decode_header(AVCodecContext *avctx, GetBitContext *gb)
> } else
> avctx->pix_fmt = AV_PIX_FMT_YUV420P;
>
> + if (s->width < 18)
> + return AVERROR_PATCHWELCOME;
> ret = ff_set_dimensions(avctx, s->width, s->height);
> if (ret < 0)
> return ret;
Always mention in the commit message which assertion fails when fixing
an assertion.
- Andreas
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