From 2a0fb7286d67c47e44aa76c237ede117b22af616 Mon Sep 17 00:00:00 2001
From: Reinhard Tartler <siretart@tauware.de>
Date: Sun, 8 Dec 2013 13:24:26 -0500
Subject: [PATCH] alsdec: check block length
Fix writing over the end
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Addresses: CVE-2013-0845
---
libavcodec/alsdec.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c
index 782a1b8b80c..f7dee7de129 100644
--- a/libavcodec/alsdec.c
+++ b/libavcodec/alsdec.c
@@ -1376,6 +1376,11 @@ static int read_frame_data(ALSDecContext *ctx, unsigned int ra_frame)
for (b = 0; b < ctx->num_blocks; b++) {
bd.block_length = div_blocks[b];
+ if (bd.block_length <= 0) {
+ av_log(ctx->avctx, AV_LOG_WARNING,
+ "Invalid block length %d in channel data!\n", bd.block_length);
+ continue;
+ }
for (c = 0; c < avctx->channels; c++) {
bd.const_block = ctx->const_block + c;
--
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