From 4e06acbde4a75cf9aa6a3e46dd3a7c6ed1ecfb8f Mon Sep 17 00:00:00 2001
From: Laurent Aimar <fenrir@videolan.org>
Date: Fri, 26 Feb 2010 18:50:01 +0000
Subject: [PATCH] Fixed a segfault in the DCA decoder with corrupted streams.

 It happens when the number of channels defined by DCAContext:acmod is lower
than DCAContext:prim_channels. In this case, dca_subsubframe() will call
qmf_32_subbands() using s->channel_order_tab[] entries equal to -1.

Originally committed as revision 22083 to svn://svn.ffmpeg.org/ffmpeg/trunk
---
 libavcodec/dca.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/libavcodec/dca.c b/libavcodec/dca.c
index 20d7144c2c..e10ced7221 100644
--- a/libavcodec/dca.c
+++ b/libavcodec/dca.c
@@ -1244,6 +1244,10 @@ static int dca_decode_frame(AVCodecContext * avctx,
         } else
             s->channel_order_tab = dca_channel_reorder_nolfe[s->amode];
 
+        if (s->prim_channels > 0 &&
+            s->channel_order_tab[s->prim_channels - 1] < 0)
+            return -1;
+
         if(avctx->request_channels == 2 && s->prim_channels > 2) {
             channels = 2;
             s->output = DCA_STEREO;