[FFmpeg-cvslog] jpeg2000dec: Check that theres a SOT before SOD

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Thu Jun  6 10:50:33 2013 +0200| [b26bcd08e670b90740f7253f21adddafb9d8c478] | committer: Michael Niedermayer

jpeg2000dec: Check that theres a SOT before SOD

Fixes out of array access

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=b26bcd08e670b90740f7253f21adddafb9d8c478
---

 libavcodec/jpeg2000dec.c |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index 4968036..fdc0a93 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -1208,9 +1208,16 @@ static int jpeg2000_read_main_headers(Jpeg2000DecoderContext *s)
         oldpos = bytestream2_tell(&s->g);
 
         if (marker == JPEG2000_SOD) {
-            Jpeg2000Tile *tile = s->tile + s->curtileno;
-            Jpeg2000TilePart *tp = tile->tile_part + tile->tp_idx;
+            Jpeg2000Tile *tile;
+            Jpeg2000TilePart *tp;
 
+            if (s->curtileno < 0) {
+                av_log(s->avctx, AV_LOG_ERROR, "Missing SOT\n");
+                return AVERROR_INVALIDDATA;
+            }
+
+            tile = s->tile + s->curtileno;
+            tp = tile->tile_part + tile->tp_idx;
             bytestream2_init(&tp->tpg, s->g.buffer, tp->tp_end - s->g.buffer);
             bytestream2_skip(&s->g, tp->tp_end - s->g.buffer);