[FFmpeg-cvslog] 4xm: check for invalid zero ac coeffs

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sun Jun 30 01:28:25 2013 +0200| [13c56e9a9cf18f33bcbc2dc1a5cf2a5f98ca9702] | committer: Michael Niedermayer

4xm: check for invalid zero ac coeffs

Signed-off-by: Michael Niedermayer <michaelni at gmx.at>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=13c56e9a9cf18f33bcbc2dc1a5cf2a5f98ca9702
---

 libavcodec/4xm.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavcodec/4xm.c b/libavcodec/4xm.c
index 3e0e681..dc84e96 100644
--- a/libavcodec/4xm.c
+++ b/libavcodec/4xm.c
@@ -525,7 +525,12 @@ static int decode_i_block(FourXContext *f, int16_t *block)
         if (code == 0xf0) {
             i += 16;
         } else {
-            level = get_xbits(&f->gb, code & 0xf);
+            if (code & 0xf) {
+                level = get_xbits(&f->gb, code & 0xf);
+            } else {
+                av_log(f->avctx, AV_LOG_ERROR, "0 coeff\n");
+                return AVERROR_INVALIDDATA;
+            }
             i    += code >> 4;
             if (i >= 64) {
                 av_log(f->avctx, AV_LOG_ERROR, "run %d oveflow\n", i);