[FFmpeg-cvslog] avcodec/webp: Fixes null pointer dereference

[Michael Niedermayer]

ffmpeg | branch: release/3.1 | Michael Niedermayer <michael at niedermayer.cc> | Wed May 10 18:37:50 2017 +0200| [f88fd9027c49f20ce0ff0b04658322314fac605e] | committer: Michael Niedermayer

avcodec/webp: Fixes null pointer dereference

Fixes: 1470/clusterfuzz-testcase-minimized-5404421666111488
Fixes: 1472/clusterfuzz-testcase-minimized-5677426430443520
Fixes: 1875/clusterfuzz-testcase-minimized-5536474562822144

Approved-by: BBB

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 67020711b7d45afa073ef671f755765035a64373)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=f88fd9027c49f20ce0ff0b04658322314fac605e
---

 libavcodec/webp.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/webp.c b/libavcodec/webp.c
index 04d898ee7b..6aa0e4aed8 100644
--- a/libavcodec/webp.c
+++ b/libavcodec/webp.c
@@ -1350,6 +1350,9 @@ static int vp8_lossy_decode_frame(AVCodecContext *avctx, AVFrame *p,
     if (ret < 0)
         return ret;
 
+    if (!*got_frame)
+        return AVERROR_INVALIDDATA;
+
     update_canvas_size(avctx, avctx->width, avctx->height);
 
     if (s->has_alpha) {