From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CAE21494C5; Thu, 15 Aug 2024 13:49:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723729746; cv=none; b=YlNCzPmHm1ogfOigq/f1zg5Q/cl/EjqvCIMnH0d6x+jMmXKOcdnkWNI3rI28oR5LMTqRJcNaYphN8QsKutDAmoy5Qj4TOBpQpHZ+PnesMvhId83mcgHcdEuaepGk5CfIJpSzjg2jg20gO1lCoO44Dx3Q/mUfc8/p74hNRqaF5OM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723729746; c=relaxed/simple; bh=tiLC25xf+lDQf5ah6son5AdOprgJaZkd8lPNvAAalX4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=jaKeIt10RHw2EE6GjLEhkJmHOsl8o3hH65SgRytfq2OdGpqz6+pSgS9qDD6NegTBSa8Ab8Rya/x9UQ2zjoqifmGOQbmUiRx5GbGxq4WzkwPT5DCJezROvo5524HtrFZLs7yQpLwHpJ96q4bPfbMrIdrhvnyZ49X40g9tiDXSNl8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lQrgzTwf; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="lQrgzTwf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C100EC32786; Thu, 15 Aug 2024 13:49:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1723729746; bh=tiLC25xf+lDQf5ah6son5AdOprgJaZkd8lPNvAAalX4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=lQrgzTwfOYN+tB0Ck8/m/Hru4mom8vAX/Ihz577stGwkz1SWSHGDpkS4fvwC/OV6v hkKgcEkhzw6p7UfnIW9wgZvAd0/gC5D3/7/pgX/QTQ8SwgMqpSbFhOlXs/KoyILofq V835O5UmSzwBd0bUo2mnkTDpUmKb306MXQBvRCbs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+ae688d469e36fb5138d0@syzkaller.appspotmail.com, stable@kernel.org, Baokun Li , Jan Kara , Theodore Tso Subject: [PATCH 5.15 193/484] ext4: make sure the first directory block is not a hole Date: Thu, 15 Aug 2024 15:20:51 +0200 Message-ID: <20240815131948.868831995@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240815131941.255804951@linuxfoundation.org> References: <20240815131941.255804951@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Baokun Li commit f9ca51596bbfd0f9c386dd1c613c394c78d9e5e6 upstream. The syzbot constructs a directory that has no dirblock but is non-inline, i.e. the first directory block is a hole. And no errors are reported when creating files in this directory in the following flow. ext4_mknod ... ext4_add_entry // Read block 0 ext4_read_dirblock(dir, block, DIRENT) bh = ext4_bread(NULL, inode, block, 0) if (!bh && (type == INDEX || type == DIRENT_HTREE)) // The first directory block is a hole // But type == DIRENT, so no error is reported. After that, we get a directory block without '.' and '..' but with a valid dentry. This may cause some code that relies on dot or dotdot (such as make_indexed_dir()) to crash. Therefore when ext4_read_dirblock() finds that the first directory block is a hole report that the filesystem is corrupted and return an error to avoid loading corrupted data from disk causing something bad. Reported-by: syzbot+ae688d469e36fb5138d0@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=ae688d469e36fb5138d0 Fixes: 4e19d6b65fb4 ("ext4: allow directory holes") Cc: stable@kernel.org Signed-off-by: Baokun Li Reviewed-by: Jan Kara Link: https://patch.msgid.link/20240702132349.2600605-3-libaokun@huaweicloud.com Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/namei.c | 17 ++++++----------- 1 file changed, 6 insertions(+), 11 deletions(-) --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -151,10 +151,11 @@ static struct buffer_head *__ext4_read_d return bh; } - if (!bh && (type == INDEX || type == DIRENT_HTREE)) { + /* The first directory block must not be a hole. */ + if (!bh && (type == INDEX || type == DIRENT_HTREE || block == 0)) { ext4_error_inode(inode, func, line, block, - "Directory hole found for htree %s block", - (type == INDEX) ? "index" : "leaf"); + "Directory hole found for htree %s block %u", + (type == INDEX) ? "index" : "leaf", block); return ERR_PTR(-EFSCORRUPTED); } if (!bh) @@ -3133,10 +3134,7 @@ bool ext4_empty_dir(struct inode *inode) EXT4_ERROR_INODE(inode, "invalid size"); return false; } - /* The first directory block must not be a hole, - * so treat it as DIRENT_HTREE - */ - bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE); + bh = ext4_read_dirblock(inode, 0, EITHER); if (IS_ERR(bh)) return false; @@ -3594,10 +3592,7 @@ static struct buffer_head *ext4_get_firs struct ext4_dir_entry_2 *de; unsigned int offset; - /* The first directory block must not be a hole, so - * treat it as DIRENT_HTREE - */ - bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE); + bh = ext4_read_dirblock(inode, 0, EITHER); if (IS_ERR(bh)) { *retval = PTR_ERR(bh); return NULL;