From 0ceca269b66ec12a23bf0907bd2c220513cdbf16 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 12 Dec 2012 12:28:45 +0100 Subject: [PATCH] alsdec: check block length Fix writing over the end Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind Signed-off-by: Michael Niedermayer --- libavcodec/alsdec.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c index 3428f2c89b..1465129f8c 100644 --- a/libavcodec/alsdec.c +++ b/libavcodec/alsdec.c @@ -553,12 +553,15 @@ 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); @@ -573,6 +576,8 @@ static void read_const_block_data(ALSDecContext *ctx, ALSBlockData *bd) // ensure constant block decoding by reusing this field *bd->const_block = 1; + + return 0; } @@ -972,7 +977,8 @@ 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;