[FFmpeg-cvslog] vorbisdec: Error on bark_map_size equal to 0.

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Fri Jan 11 00:54:12 2013 +0100| [11dcecfcca0eca1a571792c4fa3c21fb2cfddddc] | committer: Luca Barbato

vorbisdec: Error on bark_map_size equal to 0.

The value is used to calculate output LSP curve and a division by zero
and out of array accesses would occur.

CVE-2013-0894

CC: libav-stable at libav.org

Reported-by: Dale Curtis <dalecurtis at chromium.org>
Found-by: inferno at chromium.org
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=11dcecfcca0eca1a571792c4fa3c21fb2cfddddc
---

 libavcodec/vorbisdec.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libavcodec/vorbisdec.c b/libavcodec/vorbisdec.c
index 158bd6f..600083b 100644
--- a/libavcodec/vorbisdec.c
+++ b/libavcodec/vorbisdec.c
@@ -586,6 +586,11 @@ static int vorbis_parse_setup_hdr_floors(vorbis_context *vc)
             floor_setup->data.t0.order          = get_bits(gb,  8);
             floor_setup->data.t0.rate           = get_bits(gb, 16);
             floor_setup->data.t0.bark_map_size  = get_bits(gb, 16);
+            if (floor_setup->data.t0.bark_map_size == 0) {
+                av_log(vc->avccontext, AV_LOG_ERROR,
+                       "Floor 0 bark map size is 0.\n");
+                return AVERROR_INVALIDDATA;
+            }
             floor_setup->data.t0.amplitude_bits = get_bits(gb,  6);
             /* zero would result in a div by zero later *
              * 2^0 - 1 == 0                             */