[FFmpeg-cvslog] avcodec/qdm2: The smallest header seems to have 2 bytes so treat 1 as invalid

[Michael Niedermayer]

ffmpeg | branch: release/4.0 | Michael Niedermayer <michael at niedermayer.cc> | Thu Oct 31 15:22:53 2019 +0100| [61620896a1acd80e00cb8821febe39efd3724978] | committer: Michael Niedermayer

avcodec/qdm2: The smallest header seems to have 2 bytes so treat 1 as invalid

Fixes: Timeout (217sec -> 2ms)
Fixes: 18488/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_QDM2_fuzzer-5708293662310400

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit e36ccb5048f052b8b2ef08281cb607fa53a7b7e4)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=61620896a1acd80e00cb8821febe39efd3724978
---

 libavcodec/qdm2.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/qdm2.c b/libavcodec/qdm2.c
index ac8ae8cbbb..7b9d50b234 100644
--- a/libavcodec/qdm2.c
+++ b/libavcodec/qdm2.c
@@ -1704,7 +1704,7 @@ static av_cold int qdm2_decode_init(AVCodecContext *avctx)
     s->group_size = bytestream2_get_be32(&gb);
     s->fft_size = bytestream2_get_be32(&gb);
     s->checksum_size = bytestream2_get_be32(&gb);
-    if (s->checksum_size >= 1U << 28 || !s->checksum_size) {
+    if (s->checksum_size >= 1U << 28 || s->checksum_size <= 1) {
         av_log(avctx, AV_LOG_ERROR, "data block size invalid (%u)\n", s->checksum_size);
         return AVERROR_INVALIDDATA;
     }