[FFmpeg-cvslog] wmaprodec: check num_vec_coeffs for validity

[Michael Niedermayer]

ffmpeg | branch: master | Michael Niedermayer <michaelni at gmx.at> | Sat Apr 14 11:07:11 2012 +0200| [99f392a584dd10b553facc8e819f2c7e982e176d] | committer: Anton Khirnov

wmaprodec: check num_vec_coeffs for validity

Fixes CVE-2012-2789

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Anton Khirnov <anton at khirnov.net>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=99f392a584dd10b553facc8e819f2c7e982e176d
---

 libavcodec/wmaprodec.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/libavcodec/wmaprodec.c b/libavcodec/wmaprodec.c
index 60d39be..1c9c667 100644
--- a/libavcodec/wmaprodec.c
+++ b/libavcodec/wmaprodec.c
@@ -1174,7 +1174,12 @@ static int decode_subframe(WMAProDecodeCtx *s)
             int num_bits = av_log2((s->subframe_len + 3)/4) + 1;
             for (i = 0; i < s->channels_for_cur_subframe; i++) {
                 int c = s->channel_indexes_for_cur_subframe[i];
-                s->channel[c].num_vec_coeffs = get_bits(&s->gb, num_bits) << 2;
+                int num_vec_coeffs = get_bits(&s->gb, num_bits) << 2;
+                if (num_vec_coeffs > WMAPRO_BLOCK_MAX_SIZE) {
+                    av_log(s->avctx, AV_LOG_ERROR, "num_vec_coeffs %d is too large\n", num_vec_coeffs);
+                    return AVERROR_INVALIDDATA;
+                }
+                s->channel[c].num_vec_coeffs = num_vec_coeffs;
             }
         } else {
             for (i = 0; i < s->channels_for_cur_subframe; i++) {