avcodec/pngdec: Check for fctl after idat

Fixes: out of array access
Fixes: 23554/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_APNG_fuzzer-4796622520451072.fuzz

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 65b1ba680f)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2020-06-25 19:22:01 +02:00
parent a3fdeb0c3a
commit f27a510211
1 changed files with 5 additions and 0 deletions

View File

@ -984,6 +984,11 @@ static int decode_fctl_chunk(AVCodecContext *avctx, PNGDecContext *s,
return AVERROR_INVALIDDATA;
}
if (s->pic_state & PNG_IDAT) {
av_log(avctx, AV_LOG_ERROR, "fctl after IDAT\n");
return AVERROR_INVALIDDATA;
}
s->last_w = s->cur_w;
s->last_h = s->cur_h;
s->last_x_offset = s->x_offset;