Re: [FFmpeg-devel] [PATCH 1/2] avcodec/hdrdec: Check for end of input in decompress()

[Paul B Mahol <onemda@gmail.com>]

On 12/25/22, Michael Niedermayer <michael@niedermayer.cc> wrote:
> Fixes: Timeout
> Fixes:
> 54386/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_HDR_fuzzer-5053598268784640
>
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
> ---
>  libavcodec/hdrdec.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
>
> diff --git a/libavcodec/hdrdec.c b/libavcodec/hdrdec.c
> index 21d3e7f693..998227744b 100644
> --- a/libavcodec/hdrdec.c
> +++ b/libavcodec/hdrdec.c
> @@ -58,6 +58,8 @@ static int decompress(uint8_t *scanline, int w,
> GetByteContext *gb, const uint8_
>      int rshift = 0;
>
>      while (w > 0) {
> +        if (bytestream2_get_bytes_left(gb) < 4)
> +            return AVERROR_INVALIDDATA;
>          scanline[0] = bytestream2_get_byte(gb);
>          scanline[1] = bytestream2_get_byte(gb);
>          scanline[2] = bytestream2_get_byte(gb);
> @@ -143,13 +145,17 @@ static int hdr_decode_frame(AVCodecContext *avctx,
> AVFrame *p,
>          int i;
>
>          if (width < MINELEN || width > MAXELEN) {
> -            decompress(scanline, width, &gb, scanline);
> +            ret = decompress(scanline, width, &gb, scanline);
> +            if (ret < 0)
> +                return ret;
>              goto convert;
>          }
>
>          i = bytestream2_peek_byte(&gb);
>          if (i != 2) {
> -            decompress(scanline, width, &gb, scanline);
> +            ret = decompress(scanline, width, &gb, scanline);
> +            if (ret < 0)
> +                return ret;
>              goto convert;
>          }
>          bytestream2_skip(&gb, 1);
> @@ -161,7 +167,9 @@ static int hdr_decode_frame(AVCodecContext *avctx,
> AVFrame *p,
>          if (scanline[1] != 2 || scanline[2] & 128) {
>              scanline[0] = 2;
>              scanline[3] = i;
> -            decompress(scanline + 4, width - 1, &gb, scanline);
> +            ret = decompress(scanline + 4, width - 1, &gb, scanline);
> +            if (ret < 0)
> +                return ret;
>              goto convert;
>          }
>
> --
> 2.17.1
>

LGTM

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