[FFmpeg-cvslog] vorbisdec: Fix decoding bug with channel handling

[Reinhard Tartler]

ffmpeg | branch: release/0.8 | Reinhard Tartler <siretart at tauware.de> | Thu Jan  5 21:40:18 2012 +0100| [97f23c72a3815739ab28e297ce60f943349f6939] | committer: Reinhard Tartler

vorbisdec: Fix decoding bug with channel handling

Fixes Bug: #191
Chromium Bug: #101458
CVE-2011-3895

Signed-off-by: Reinhard Tartler <siretart at tauware.de>
(cherry picked from commit e6d527ff729e42d80e4756cab779ff4ad693631b)

Signed-off-by: Reinhard Tartler <siretart at tauware.de>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=97f23c72a3815739ab28e297ce60f943349f6939
---

 libavcodec/vorbisdec.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/libavcodec/vorbisdec.c b/libavcodec/vorbisdec.c
index 017102e..8145814 100644
--- a/libavcodec/vorbisdec.c
+++ b/libavcodec/vorbisdec.c
@@ -660,7 +660,7 @@ static int vorbis_parse_setup_hdr_residues(vorbis_context *vc)
         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",
@@ -1466,6 +1466,7 @@ static int vorbis_parse_audio_packet(vorbis_context *vc)
     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");
@@ -1540,9 +1541,14 @@ static int vorbis_parse_audio_packet(vorbis_context *vc)
             }
         }
         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