[FFmpeg-cvslog] avcodec/magicyuv: Check that vlc len is not too large

[Michael Niedermayer]

ffmpeg | branch: release/3.2 | Michael Niedermayer <michael at niedermayer.cc> | Wed Jul 12 17:25:16 2017 +0200| [aa01a35dd507e4e692ea37e015fa7a45d7566851] | committer: Michael Niedermayer

avcodec/magicyuv: Check that vlc len is not too large

Fixes: runtime error: shift exponent -95 is negative
Fixes: 2568/clusterfuzz-testcase-minimized-4926115716005888

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 341f01290c2353669ed2263f56e1a9f4c67cc597)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=aa01a35dd507e4e692ea37e015fa7a45d7566851
---

 libavcodec/magicyuv.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libavcodec/magicyuv.c b/libavcodec/magicyuv.c
index 2c312bec17..742e6ecb8c 100644
--- a/libavcodec/magicyuv.c
+++ b/libavcodec/magicyuv.c
@@ -84,6 +84,8 @@ static int huff_build(VLC *vlc, uint8_t *len)
     for (i = 0; i < 256; i++) {
         he[i].sym = 255 - i;
         he[i].len = len[i];
+        if (len[i] == 0 || len[i] > 32)
+            return AVERROR_INVALIDDATA;
     }
     AV_QSORT(he, 256, HuffEntry, huff_cmp_len);