vorbisdec: Fix decoding bug with channel handling
authorReinhard Tartler <siretart@tauware.de>
Thu, 5 Jan 2012 20:40:18 +0000 (21:40 +0100)
committerReinhard Tartler <siretart@tauware.de>
Sun, 8 Jan 2012 08:10:55 +0000 (09:10 +0100)
Fixes Bug: #191
Chromium Bug: #101458
CVE-2011-3895

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

Signed-off-by: Reinhard Tartler <siretart@tauware.de>
libavcodec/vorbisdec.c

index 017102e..8145814 100644 (file)
@@ -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