From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E373BC00140 for ; Mon, 15 Aug 2022 19:58:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241362AbiHOT6h (ORCPT ); Mon, 15 Aug 2022 15:58:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345885AbiHOT4T (ORCPT ); Mon, 15 Aug 2022 15:56:19 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 922787645E; Mon, 15 Aug 2022 11:52:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2D996B810A5; Mon, 15 Aug 2022 18:52:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 734E5C433C1; Mon, 15 Aug 2022 18:52:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660589537; bh=UJmdtNp9UclGRqO3oGh5Wh3J+d7Eg6EFFK3qiBFPpdU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q5ZY1KHTY8dXVjLSX9IcXkXJUdM18qN/jD1nIZPSNJZgOINlbK0sCxv2AKtML3bcY wiNdQFg0fSpC4alx79nLcOAI1+0p7rytdEXEWpPVbAeW5ACdhT6xPyg3sBCSH8VQit iHER1zihIA0kZfFd2cXoN1izv7lXbrjBkLcoykNY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, stable@kernel.org, Lukas Czerner , Andreas Dilger , Theodore Tso , Sasha Levin Subject: [PATCH 5.15 749/779] ext4: make sure ext4_append() always allocates new block Date: Mon, 15 Aug 2022 20:06:33 +0200 Message-Id: <20220815180409.494538455@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180337.130757997@linuxfoundation.org> References: <20220815180337.130757997@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lukas Czerner [ Upstream commit b8a04fe77ef1360fbf73c80fddbdfeaa9407ed1b ] ext4_append() must always allocate a new block, otherwise we run the risk of overwriting existing directory block corrupting the directory tree in the process resulting in all manner of problems later on. Add a sanity check to see if the logical block is already allocated and error out if it is. Cc: stable@kernel.org Signed-off-by: Lukas Czerner Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/20220704142721.157985-2-lczerner@redhat.com Signed-off-by: Theodore Ts'o Signed-off-by: Sasha Levin --- fs/ext4/namei.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index ac0b7e53591f..5821638cb893 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -54,6 +54,7 @@ static struct buffer_head *ext4_append(handle_t *handle, struct inode *inode, ext4_lblk_t *block) { + struct ext4_map_blocks map; struct buffer_head *bh; int err; @@ -63,6 +64,21 @@ static struct buffer_head *ext4_append(handle_t *handle, return ERR_PTR(-ENOSPC); *block = inode->i_size >> inode->i_sb->s_blocksize_bits; + map.m_lblk = *block; + map.m_len = 1; + + /* + * We're appending new directory block. Make sure the block is not + * allocated yet, otherwise we will end up corrupting the + * directory. + */ + err = ext4_map_blocks(NULL, inode, &map, 0); + if (err < 0) + return ERR_PTR(err); + if (err) { + EXT4_ERROR_INODE(inode, "Logical block already allocated"); + return ERR_PTR(-EFSCORRUPTED); + } bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE); if (IS_ERR(bh)) -- 2.35.1