On 9/3/2019 8:13 AM, Michael Niedermayer wrote: > On Mon, Sep 02, 2019 at 09:40:47PM -0300, James Almer wrote: >> On 9/2/2019 9:14 PM, Michael Niedermayer wrote: >>> Fixes: OOM >>> Fixes: >>> 16627/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APE_fuzzer-5638059583864832 >>> >>> Found-by: continuous fuzzing process >>> https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg >>> Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> >>> --- >>> libavcodec/apedec.c | 3 +++ >>> 1 file changed, 3 insertions(+) >>> >>> diff --git a/libavcodec/apedec.c b/libavcodec/apedec.c >>> index e218f7c043..774ce18531 100644 >>> --- a/libavcodec/apedec.c >>> +++ b/libavcodec/apedec.c >>> @@ -1475,6 +1475,9 @@ static int ape_decode_frame(AVCodecContext *avctx, >>> void *data, >>> return AVERROR_INVALIDDATA; >>> } >>> >>> + if (nblocks * (int64_t)avctx->channels > avctx->max_samples) >>> + return AVERROR(EINVAL); >>> + >> >> Shouldn't this be checked in ff_get_buffer()? Same as max_pixels, but >> checking "frame->nb_samples > avctx->max_samples" instead or >> width/height. Otherwise it will barely be used. > > you are correct, it should be checked in *get_buffer somewhere too. > But the offending allocation occurs before any *get_buffer calls so > this check here is what is neccessary and sufficient for this specific > bug
If the allocation you're talking about is https://git.videolan.org/?p=ffmpeg.git;a=blob;f=libavcodec/apedec.c;h=490b11b94e0b1666f18248b2b247c874fed6e0bc;hb=HEAD#l1500 then you could just move it (and the five lines that follow it) right below the ff_get_buffer() call. But it should be ok either way. > > Thanks > > [...] > > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
