[FFmpeg-cvslog] jpeg2000dec: read and check curtileno

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Wed May 22 02:29:00 2013 +0200| [fec8783883f789802ba6596ce4c324aa5c040754] | committer: Michael Niedermayer

jpeg2000dec: read and check curtileno

Fixes out of array accesses
Code ported from j2kdec

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=fec8783883f789802ba6596ce4c324aa5c040754
---

 libavcodec/jpeg2000dec.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 4768f7e..4e03e0e 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -416,7 +416,11 @@ static int get_sot(Jpeg2000DecoderContext *s, int n)
     if (bytestream2_get_bytes_left(&s->g) < 8)
         return AVERROR(EINVAL);
 
-    Isot = bytestream2_get_be16u(&s->g);        // Isot
+    s->curtileno = Isot = bytestream2_get_be16u(&s->g);        // Isot
+    if((unsigned)s->curtileno >= s->numXtiles * s->numYtiles){
+        s->curtileno=0;
+        return AVERROR(EINVAL);
+    }
     if (Isot) {
         av_log(s->avctx, AV_LOG_ERROR,
                "Not a DCINEMA JP2K file: more than one tile\n");