[FFmpeg-cvslog] alac: Do bounds checking of lpc_order read from the bitstream

[Martin Storsjö]

ffmpeg | branch: release/1.1 | Martin Storsjö <martin at martin.st> | Sat Sep 28 00:22:52 2013 +0300| [78aa2ed620178044a227fbbe48f749c0dc86023f] | committer: Luca Barbato

alac: Do bounds checking of lpc_order read from the bitstream

In lpc_prediction(), we write up to array element 'lpc_order' in
an array allocated to hold 'max_samples_per_frame' elements.

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable at libav.org
Signed-off-by: Martin Storsjö <martin at martin.st>
(cherry picked from commit 59480abce7e4238e22b3a4a904a9fe6abf4e4188)
Signed-off-by: Luca Barbato <lu_zero at gentoo.org>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=78aa2ed620178044a227fbbe48f749c0dc86023f
---

 libavcodec/alac.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 72e9353..139e352 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -315,6 +315,9 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
             rice_history_mult[ch] = get_bits(&alac->gb, 3);
             lpc_order[ch]         = get_bits(&alac->gb, 5);
 
+            if (lpc_order[ch] >= alac->max_samples_per_frame)
+                return AVERROR_INVALIDDATA;
+
             /* read the predictor table */
             for (i = lpc_order[ch] - 1; i >= 0; i--)
                 lpc_coefs[ch][i] = get_sbits(&alac->gb, 16);