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 X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0CA5FC3F357 for ; Thu, 27 Feb 2020 13:46:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D6198246A5 for ; Thu, 27 Feb 2020 13:46:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811218; bh=mUr4reYLoAEnHk+1kcjav4hCT/FUkm9BEbDfdhCOAxE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=apM6YM9fkA7nUJCqpgPrki/Iby70YeQtZrsVPqs6qyFk/PpkRPrx79bJdDt9luXpr 9SYt24G9gotkAhSWxZzgnq2AsO+DJKCm+FnPeFWcpuowwb0TZ0dh8SuA8TA48W2A8r RQFU60zK0Omh2N41YhnucrfOxEdMiKPgO7jBJWmE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730369AbgB0Nq5 (ORCPT ); Thu, 27 Feb 2020 08:46:57 -0500 Received: from mail.kernel.org ([198.145.29.99]:43202 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730112AbgB0Nqw (ORCPT ); Thu, 27 Feb 2020 08:46:52 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D19CA2469F; Thu, 27 Feb 2020 13:46:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1582811212; bh=mUr4reYLoAEnHk+1kcjav4hCT/FUkm9BEbDfdhCOAxE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=i+kYYFTxvuFpOGtqgcTDf1UXHLEjOmzBiZecuGFDFreRn85nsTt9dAVBByX2AwDwA ntypBg0nA3+vUTVcHgEQ698J/Ro76kBiW7C+pTlDDeNVUxVwtKjZbbQIwKN1bZaO0U fZaBHEIRN6z2GXJDqGCDWAib4he+tZ9KY1NhsYss= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Andreas Dilger , Jan Kara , Theodore Tso , stable@kernel.org Subject: [PATCH 4.9 008/165] ext4: fix checksum errors with indexed dirs Date: Thu, 27 Feb 2020 14:34:42 +0100 Message-Id: <20200227132232.335020824@linuxfoundation.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200227132230.840899170@linuxfoundation.org> References: <20200227132230.840899170@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jan Kara commit 48a34311953d921235f4d7bbd2111690d2e469cf upstream. DIR_INDEX has been introduced as a compat ext4 feature. That means that even kernels / tools that don't understand the feature may modify the filesystem. This works because for kernels not understanding indexed dir format, internal htree nodes appear just as empty directory entries. Index dir aware kernels then check the htree structure is still consistent before using the data. This all worked reasonably well until metadata checksums were introduced. The problem is that these effectively made DIR_INDEX only ro-compatible because internal htree nodes store checksums in a different place than normal directory blocks. Thus any modification ignorant to DIR_INDEX (or just clearing EXT4_INDEX_FL from the inode) will effectively cause checksum mismatch and trigger kernel errors. So we have to be more careful when dealing with indexed directories on filesystems with checksumming enabled. 1) We just disallow loading any directory inodes with EXT4_INDEX_FL when DIR_INDEX is not enabled. This is harsh but it should be very rare (it means someone disabled DIR_INDEX on existing filesystem and didn't run e2fsck), e2fsck can fix the problem, and we don't want to answer the difficult question: "Should we rather corrupt the directory more or should we ignore that DIR_INDEX feature is not set?" 2) When we find out htree structure is corrupted (but the filesystem and the directory should in support htrees), we continue just ignoring htree information for reading but we refuse to add new entries to the directory to avoid corrupting it more. Link: https://lore.kernel.org/r/20200210144316.22081-1-jack@suse.cz Fixes: dbe89444042a ("ext4: Calculate and verify checksums for htree nodes") Reviewed-by: Andreas Dilger Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/dir.c | 14 ++++++++------ fs/ext4/ext4.h | 5 ++++- fs/ext4/inode.c | 12 ++++++++++++ fs/ext4/namei.c | 7 +++++++ 4 files changed, 31 insertions(+), 7 deletions(-) --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -124,12 +124,14 @@ static int ext4_readdir(struct file *fil if (err != ERR_BAD_DX_DIR) { return err; } - /* - * We don't set the inode dirty flag since it's not - * critical that it get flushed back to the disk. - */ - ext4_clear_inode_flag(file_inode(file), - EXT4_INODE_INDEX); + /* Can we just clear INDEX flag to ignore htree information? */ + if (!ext4_has_metadata_csum(sb)) { + /* + * We don't set the inode dirty flag since it's not + * critical that it gets flushed back to the disk. + */ + ext4_clear_inode_flag(inode, EXT4_INODE_INDEX); + } } if (ext4_has_inline_data(inode)) { --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2375,8 +2375,11 @@ int ext4_insert_dentry(struct inode *dir struct ext4_filename *fname); static inline void ext4_update_dx_flag(struct inode *inode) { - if (!ext4_has_feature_dir_index(inode->i_sb)) + if (!ext4_has_feature_dir_index(inode->i_sb)) { + /* ext4_iget() should have caught this... */ + WARN_ON_ONCE(ext4_has_feature_metadata_csum(inode->i_sb)); ext4_clear_inode_flag(inode, EXT4_INODE_INDEX); + } } static unsigned char ext4_filetype_table[] = { DT_UNKNOWN, DT_REG, DT_DIR, DT_CHR, DT_BLK, DT_FIFO, DT_SOCK, DT_LNK --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4594,6 +4594,18 @@ struct inode *ext4_iget(struct super_blo ret = -EFSCORRUPTED; goto bad_inode; } + /* + * If dir_index is not enabled but there's dir with INDEX flag set, + * we'd normally treat htree data as empty space. But with metadata + * checksumming that corrupts checksums so forbid that. + */ + if (!ext4_has_feature_dir_index(sb) && ext4_has_metadata_csum(sb) && + ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) { + EXT4_ERROR_INODE(inode, + "iget: Dir with htree data on filesystem without dir_index feature."); + ret = -EFSCORRUPTED; + goto bad_inode; + } ei->i_disksize = inode->i_size; #ifdef CONFIG_QUOTA ei->i_reserved_quota = 0; --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -2148,6 +2148,13 @@ static int ext4_add_entry(handle_t *hand retval = ext4_dx_add_entry(handle, &fname, dir, inode); if (!retval || (retval != ERR_BAD_DX_DIR)) goto out; + /* Can we just ignore htree data? */ + if (ext4_has_metadata_csum(sb)) { + EXT4_ERROR_INODE(dir, + "Directory has corrupted htree index."); + retval = -EFSCORRUPTED; + goto out; + } ext4_clear_inode_flag(dir, EXT4_INODE_INDEX); dx_fallback++; ext4_mark_inode_dirty(handle, dir);