[FFmpeg-devel] [PATCH] avcodec/fic: Check available input space for cursor

[Paul B Mahol]

On 5/5/18, wm4 <nfxjfg at googlemail.com> wrote:
> On Sat,  5 May 2018 22:47:37 +0200
> Michael Niedermayer <michael at niedermayer.cc> wrote:
>
>> Fixes: out of array read
>> Fixes:
>> 6546/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_FIC_fuzzer-6317064647081984
>>
>> 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/fic.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/libavcodec/fic.c b/libavcodec/fic.c
>> index d7ee370423..6824a5683c 100644
>> --- a/libavcodec/fic.c
>> +++ b/libavcodec/fic.c
>> @@ -337,6 +337,11 @@ static int fic_decode_frame(AVCodecContext *avctx,
>> void *data,
>>          skip_cursor = 1;
>>      }
>>
>> +    if (!skip_cursor && avpkt->size < 59 + 32 * 32 * 4) {
>> +        av_log(avctx, AV_LOG_WARNING, "Input is cursorless\n");
>> +        skip_cursor = 1;
>> +    }
>> +
>>      /* Slice height for all but the last slice. */
>>      ctx->slice_h = 16 * (ctx->aligned_height >> 4) / nslices;
>>      if (ctx->slice_h % 16)
>
> No warning needed.

Agreed.