fix nb_samples < order case

patch from ffmpeg to fix CVE-2013-0856

Change-Id: I8ea9793b2b7f83a1d871c18a0ffca820f5e170d4

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 0d2a7ca..535ded1 100644 (file)
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -186,7 +186,7 @@ static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
     }
 
     /* read warm-up samples */
-    for (i = 1; i <= lpc_order; i++)
+    for (i = 1; i <= lpc_order && i < nb_samples; i++)
         buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i], bps);
 
     /* NOTE: 4 and 8 are very common cases that could be optimized. */