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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,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 412E7C28CF6 for ; Wed, 1 Aug 2018 18:31:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E6F3A20840 for ; Wed, 1 Aug 2018 18:31:18 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E6F3A20840 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388320AbeHAUSG (ORCPT ); Wed, 1 Aug 2018 16:18:06 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46142 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404201AbeHATDf (ORCPT ); Wed, 1 Aug 2018 15:03:35 -0400 Received: from localhost (D57E6652.static.ziggozakelijk.nl [213.126.102.82]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 53EA0125F; Wed, 1 Aug 2018 17:09:34 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Theodore Tso , stable@kernel.org Subject: [PATCH 4.17 305/336] ext4: check for allocation block validity with block group locked Date: Wed, 1 Aug 2018 18:50:40 +0200 Message-Id: <20180801165040.722153415@linuxfoundation.org> X-Mailer: git-send-email 2.18.0 In-Reply-To: <20180801165028.930831994@linuxfoundation.org> References: <20180801165028.930831994@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.17-stable review patch. If anyone has any objections, please let me know. ------------------ From: Theodore Ts'o commit 8d5a803c6a6ce4ec258e31f76059ea5153ba46ef upstream. With commit 044e6e3d74a3: "ext4: don't update checksum of new initialized bitmaps" the buffer valid bit will get set without actually setting up the checksum for the allocation bitmap, since the checksum will get calculated once we actually allocate an inode or block. If we are doing this, then we need to (re-)check the verified bit after we take the block group lock. Otherwise, we could race with another process reading and verifying the bitmap, which would then complain about the checksum being invalid. https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1780137 Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/balloc.c | 3 +++ fs/ext4/ialloc.c | 3 +++ 2 files changed, 6 insertions(+) --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -379,6 +379,8 @@ static int ext4_validate_block_bitmap(st return -EFSCORRUPTED; ext4_lock_group(sb, block_group); + if (buffer_verified(bh)) + goto verified; if (unlikely(!ext4_block_bitmap_csum_verify(sb, block_group, desc, bh))) { ext4_unlock_group(sb, block_group); @@ -401,6 +403,7 @@ static int ext4_validate_block_bitmap(st return -EFSCORRUPTED; } set_buffer_verified(bh); +verified: ext4_unlock_group(sb, block_group); return 0; } --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -91,6 +91,8 @@ static int ext4_validate_inode_bitmap(st return -EFSCORRUPTED; ext4_lock_group(sb, block_group); + if (buffer_verified(bh)) + goto verified; blk = ext4_inode_bitmap(sb, desc); if (!ext4_inode_bitmap_csum_verify(sb, block_group, desc, bh, EXT4_INODES_PER_GROUP(sb) / 8)) { @@ -108,6 +110,7 @@ static int ext4_validate_inode_bitmap(st return -EFSBADCRC; } set_buffer_verified(bh); +verified: ext4_unlock_group(sb, block_group); return 0; }