From nobody Mon Sep 29 21:17:52 2025 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 83970C25B0D for ; Tue, 16 Aug 2022 04:54:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232861AbiHPEyi (ORCPT ); Tue, 16 Aug 2022 00:54:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47192 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233789AbiHPEvy (ORCPT ); Tue, 16 Aug 2022 00:51:54 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E065B1A25CF; Mon, 15 Aug 2022 13:49:44 -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 12564B811AB; Mon, 15 Aug 2022 20:49:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 677CFC433D6; Mon, 15 Aug 2022 20:49:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1660596581; bh=NEkv50wXzLdjjphvgfhiudZOSz2eMYNGuhjHWGxHaKM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OYl6pCAo2QjiWqCGUIDyIv0yCRIJi5/zT+LKDPa2j21G0rJ7EV0tukfWRiFD2cDq+ cWyoero55d+0vBXdvjTH2zg1Oe3xq+x66X3+S8nNa12JhhjYZVYMPjaO4zpacTjZ5O TT/klrXDU8SeHkmeUAf5htDBh+E7GA7MVx5Aaygg= 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 5.19 1126/1157] ext4: make sure ext4_append() always allocates new block Date: Mon, 15 Aug 2022 20:08:02 +0200 Message-Id: <20220815180525.397307272@linuxfoundation.org> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220815180439.416659447@linuxfoundation.org> References: <20220815180439.416659447@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 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 cf460aa4f81d..4af441494e09 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; =20 @@ -63,6 +64,21 @@ static struct buffer_head *ext4_append(handle_t *handle, return ERR_PTR(-ENOSPC); =20 *block =3D inode->i_size >> inode->i_sb->s_blocksize_bits; + map.m_lblk =3D *block; + map.m_len =3D 1; + + /* + * We're appending new directory block. Make sure the block is not + * allocated yet, otherwise we will end up corrupting the + * directory. + */ + err =3D 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); + } =20 bh =3D ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE); if (IS_ERR(bh)) --=20 2.35.1