[FFmpeg-cvslog] avcodec/ilbcdec: Check startindex

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michael at niedermayer.cc> | Sun Oct 21 00:35:12 2018 +0200| [e90f0ac334f2bec0961955dceb824148594a4016] | committer: Michael Niedermayer

avcodec/ilbcdec: Check startindex

Fixes: Out of array read
Fixes: 10789/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ILBC_fuzzer-5153255445757952

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Paul B Mahol <onemda at gmail.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=e90f0ac334f2bec0961955dceb824148594a4016
---

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

diff --git a/libavcodec/ilbcdec.c b/libavcodec/ilbcdec.c
index 8f234b98e1..8a6dbe0b75 100644
--- a/libavcodec/ilbcdec.c
+++ b/libavcodec/ilbcdec.c
@@ -1372,7 +1372,7 @@ static int ilbc_decode_frame(AVCodecContext *avctx, void *data,
 
     if (unpack_frame(s))
         mode = 0;
-    if (s->frame.start < 1)
+    if (s->frame.start < 1 || s->frame.start > 5)
         mode = 0;
 
     if (mode) {