Fix vorbis decoder bug.

patches/to_upstream/48_vorbis_residue_buffer.patch

+diff -wurp -N orig/libavcodec/vorbisdec.c patched-ffmpeg/libavcodec/vorbisdec.c
+--- orig/libavcodec/vorbisdec.c 2011-10-27 15:48:42.027540743 -0700
++++ patched-ffmpeg/libavcodec/vorbisdec.c       2011-10-27 16:00:51.835226983 -0700
+@@ -660,7 +660,7 @@ static int vorbis_parse_setup_hdr_residu
+         res_setup->partition_size = get_bits(gb, 24) + 1;
+         /* Validations to prevent a buffer overflow later. */
+         if (res_setup->begin>res_setup->end ||
+-            res_setup->end > vc->avccontext->channels * vc->blocksize[1] / 2 ||
++            res_setup->end > (res_setup->type == 2 ? vc->avccontext->channels : 1) * vc->blocksize[1] / 2 ||
+             (res_setup->end-res_setup->begin) / res_setup->partition_size > V_MAX_PARTITIONS) {
+             av_log(vc->avccontext, AV_LOG_ERROR,
+                    "partition out of bounds: type, begin, end, size, blocksize: %"PRIu16", %"PRIu32", %"PRIu32", %u, %"PRIu32"\n",
+@@ -1468,6 +1468,7 @@ static int vorbis_parse_audio_packet(vor
+     uint8_t res_chan[255];
+     unsigned res_num = 0;
+     int retlen  = 0;
++    int ch_left = vc->audio_channels;
+ 
+     if (get_bits1(gb)) {
+         av_log(vc->avccontext, AV_LOG_ERROR, "Not a Vorbis I audio packet.\n");
+@@ -1542,9 +1543,14 @@ static int vorbis_parse_audio_packet(vor
+             }
+         }
+         residue = &vc->residues[mapping->submap_residue[i]];
++        if (ch_left < ch) {
++            av_log(vc->avccontext, AV_LOG_ERROR, "Too many channels in vorbis_floor_decode.\n");
++            return -1;
++        }
+         vorbis_residue_decode(vc, residue, ch, do_not_decode, ch_res_ptr, blocksize/2);
+ 
+         ch_res_ptr += ch * blocksize / 2;
++        ch_left -= ch;
+     }
+ 
+ // Inverse coupling