[FFmpeg-cvslog] avcodec/jpeg2000dwt: Check ndeclevels before calling dwt_decode*()

[Michael Niedermayer]

ffmpeg | branch: release/2.6 | Michael Niedermayer <michael at niedermayer.cc> | Fri Nov 27 20:52:39 2015 +0100| [20a96b9d8c71b77761b82edd1971dc54354c175f] | committer: Michael Niedermayer

avcodec/jpeg2000dwt: Check ndeclevels before calling dwt_decode*()

Fixes out of array access
Fixes: 01859c9a9ac6cd60a008274123275574/asan_heap-oob_1dff571_8250_50d3d1611e294c3519fd1fa82198b69b.avi

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 75422280fbcdfbe9dc56bde5525b4d8b280f1bc5)

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=20a96b9d8c71b77761b82edd1971dc54354c175f
---

 libavcodec/jpeg2000dwt.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/jpeg2000dwt.c b/libavcodec/jpeg2000dwt.c
index ceceda3..015a4fe 100644
--- a/libavcodec/jpeg2000dwt.c
+++ b/libavcodec/jpeg2000dwt.c
@@ -555,6 +555,9 @@ int ff_dwt_encode(DWTContext *s, void *t)
 
 int ff_dwt_decode(DWTContext *s, void *t)
 {
+    if (s->ndeclevels == 0)
+        return 0;
+
     switch (s->type) {
     case FF_DWT97:
         dwt_decode97_float(s, t);