[FFmpeg-cvslog] alsdec: check block length
Michael Niedermayer
git at videolan.org
Sun Feb 17 23:45:46 CET 2013
ffmpeg | branch: release/0.8 | Michael Niedermayer <michaelni at gmx.at> | Wed Dec 12 12:28:45 2012 +0100| [760929117df0d6349a2cb56af084d8a13ee7f33a] | committer: Michael Niedermayer
alsdec: check block length
Fix writing over the end
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
(cherry picked from commit 0ceca269b66ec12a23bf0907bd2c220513cdbf16)
Signed-off-by: Michael Niedermayer <michaelni at gmx.at>
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=760929117df0d6349a2cb56af084d8a13ee7f33a
---
libavcodec/alsdec.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
index cb679d9..8cb5a60 100644
--- a/libavcodec/alsdec.c
+++ b/libavcodec/alsdec.c
@@ -551,12 +551,15 @@ static void get_block_sizes(ALSDecContext *ctx, unsigned int *div_blocks,
/** Read the block data for a constant block
*/
-static void read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
+static int read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
{
ALSSpecificConfig *sconf = &ctx->sconf;
AVCodecContext *avctx = ctx->avctx;
GetBitContext *gb = &ctx->gb;
+ if (bd->block_length <= 0)
+ return -1;
+
*bd->raw_samples = 0;
*bd->const_block = get_bits1(gb); // 1 = constant value, 0 = zero block (silence)
bd->js_blocks = get_bits1(gb);
@@ -571,6 +574,8 @@ static void read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd)
// ensure constant block decoding by reusing this field
*bd->const_block = 1;
+
+ return 0;
}
@@ -970,7 +975,8 @@ static int read_block(ALSDecContext *ctx, ALSBlockData *bd)
if (read_var_block_data(ctx, bd))
return -1;
} else {
- read_const_block_data(ctx, bd);
+ if (read_const_block_data(ctx, bd) < 0)
+ return -1;
}
return 0;
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