[FFmpeg-devel] [PATCH] avcodec/tiff: Remove messing with jpeg context

[Paul B Mahol]

Please confirm you are not breaking tile files in any way.

On Sat, Dec 25, 2021 at 11:43 PM Michael Niedermayer <michael at niedermayer.cc>
wrote:

> The whole concept is just not correct, also as it seems not to be needed
> at all, all dng files i have decode without this.
>
> Fixes: various crashes
> Fixes:
> 42937/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-4625073334517760
> Fixes:
> 42938/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-4643368217477120
> Fixes:
> 42939/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-4925325908246528
> Fixes:
> 42940/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-4925378806808576
> Fixes:
> 42941/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-6202009265504256
> Fixes:
> 42944/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_TIFF_fuzzer-6076860998483968
>
> Found-by: continuous fuzzing process
> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
> Signed-off-by
> <https://github.com/google/oss-fuzz/tree/master/projects/ffmpegSigned-off-by>:
> Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/tiff.c | 24 ++----------------------
>  1 file changed, 2 insertions(+), 22 deletions(-)
>
> diff --git a/libavcodec/tiff.c b/libavcodec/tiff.c
> index 60773d59ed0..fd85d104dc4 100644
> --- a/libavcodec/tiff.c
> +++ b/libavcodec/tiff.c
> @@ -721,20 +721,6 @@ static int dng_decode_jpeg(AVCodecContext *avctx,
> AVFrame *frame,
>      return 0;
>  }
>
> -static int dng_decode_strip(AVCodecContext *avctx, AVFrame *frame)
> -{
> -    TiffContext *s = avctx->priv_data;
> -    int ret = ff_set_dimensions(s->avctx_mjpeg, s->width, s->height);
> -
> -    if (ret < 0)
> -        return ret;
> -
> -    s->jpgframe->width  = s->width;
> -    s->jpgframe->height = s->height;
> -
> -    return dng_decode_jpeg(avctx, frame, s->stripsize, 0, 0, s->width,
> s->height);
> -}
> -
>  static int tiff_unpack_strip(TiffContext *s, AVFrame *p, uint8_t *dst,
> int stride,
>                               const uint8_t *src, int size, int
> strip_start, int lines)
>  {
> @@ -856,7 +842,7 @@ static int tiff_unpack_strip(TiffContext *s, AVFrame
> *p, uint8_t *dst, int strid
>              av_log(s->avctx, AV_LOG_ERROR, "More than one DNG JPEG strips
> unsupported\n");
>              return AVERROR_PATCHWELCOME;
>          }
> -        if ((ret = dng_decode_strip(s->avctx, p)) < 0)
> +        if ((ret = dng_decode_jpeg(s->avctx, p, s->stripsize, 0, 0,
> s->width, s->height)) < 0)
>              return ret;
>          return 0;
>      }
> @@ -972,13 +958,7 @@ static int dng_decode_tiles(AVCodecContext *avctx,
> AVFrame *frame,
>      int has_width_leftover, has_height_leftover;
>      int tile_x = 0, tile_y = 0;
>      int pos_x = 0, pos_y = 0;
> -    int ret = ff_set_dimensions(s->avctx_mjpeg, s->tile_width,
> s->tile_length);
> -
> -    if (ret < 0)
> -        return ret;
> -
> -    s->jpgframe->width  = s->tile_width;
> -    s->jpgframe->height = s->tile_length;
> +    int ret;
>
>      has_width_leftover = (s->width % s->tile_width != 0);
>      has_height_leftover = (s->height % s->tile_length != 0);
> --
> 2.17.1
>
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