[FFmpeg-cvslog] jpeg2000dec: dont set ncomponents to an invalid value

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Fri Jun 14 00:35:52 2013 +0200| [129edcb50facad324d80a1e28b6d4be05ce70ab7] | committer: Michael Niedermayer

jpeg2000dec: dont set ncomponents to an invalid value

Fixes out of array accesses

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=129edcb50facad324d80a1e28b6d4be05ce70ab7
---

 libavcodec/jpeg2000dec.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/libavcodec/jpeg2000dec.c b/libavcodec/jpeg2000dec.c
index da510c6..87a1d58 100644
--- a/libavcodec/jpeg2000dec.c
+++ b/libavcodec/jpeg2000dec.c
@@ -160,6 +160,7 @@ static int tag_tree_decode(Jpeg2000DecoderContext *s, Jpeg2000TgtNode *node,
 static int get_siz(Jpeg2000DecoderContext *s)
 {
     int i;
+    int ncomponents;
 
     if (bytestream2_get_bytes_left(&s->g) < 36)
         return AVERROR(EINVAL);
@@ -173,12 +174,14 @@ static int get_siz(Jpeg2000DecoderContext *s)
     s->tile_height    = bytestream2_get_be32u(&s->g); // YTSiz
     s->tile_offset_x  = bytestream2_get_be32u(&s->g); // XT0Siz
     s->tile_offset_y  = bytestream2_get_be32u(&s->g); // YT0Siz
-    s->ncomponents    = bytestream2_get_be16u(&s->g); // CSiz
+    ncomponents       = bytestream2_get_be16u(&s->g); // CSiz
 
-    if (s->ncomponents <= 0 || s->ncomponents > 4) {
-        av_log(s->avctx, AV_LOG_ERROR, "unsupported/invalid ncomponents: %d\n", s->ncomponents);
+    if (ncomponents <= 0 || ncomponents > 4) {
+        av_log(s->avctx, AV_LOG_ERROR, "unsupported/invalid ncomponents: %d\n", ncomponents);
         return AVERROR(EINVAL);
     }
+    s->ncomponents = ncomponents;
+
     if (s->tile_width<=0 || s->tile_height<=0)
         return AVERROR(EINVAL);