From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:35672 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404341AbeKTDXg (ORCPT ); Mon, 19 Nov 2018 22:23:36 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Anatoly Trosinenko , Nicolas Pitre Subject: [PATCH 4.4 081/160] Cramfs: fix abad comparison when wrap-arounds occur Date: Mon, 19 Nov 2018 17:28:40 +0100 Message-Id: <20181119162639.071893784@linuxfoundation.org> In-Reply-To: <20181119162630.031306128@linuxfoundation.org> References: <20181119162630.031306128@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Nicolas Pitre commit 672ca9dd13f1aca0c17516f76fc5b0e8344b3e46 upstream. It is possible for corrupted filesystem images to produce very large block offsets that may wrap when a length is added, and wrongly pass the buffer size test. Reported-by: Anatoly Trosinenko Signed-off-by: Nicolas Pitre Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/cramfs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/fs/cramfs/inode.c +++ b/fs/cramfs/inode.c @@ -185,7 +185,8 @@ static void *cramfs_read(struct super_bl continue; blk_offset = (blocknr - buffer_blocknr[i]) << PAGE_CACHE_SHIFT; blk_offset += offset; - if (blk_offset + len > BUFFER_SIZE) + if (blk_offset > BUFFER_SIZE || + blk_offset + len > BUFFER_SIZE) continue; return read_buffers[i] + blk_offset; }