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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 CF9FAC55186 for ; Thu, 23 Apr 2020 23:21:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B8F192077D for ; Thu, 23 Apr 2020 23:21:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729813AbgDWXVp (ORCPT ); Thu, 23 Apr 2020 19:21:45 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:48498 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728186AbgDWXGc (ORCPT ); Thu, 23 Apr 2020 19:06:32 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1jRkvL-0004be-DS; Fri, 24 Apr 2020 00:06:27 +0100 Received: from ben by deadeye with local (Exim 4.93) (envelope-from ) id 1jRkvK-00E6iV-0C; Fri, 24 Apr 2020 00:06:26 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "David Sterba" , "Johannes Thumshirn" , "Nikolay Borisov" , "Qu Wenruo" Date: Fri, 24 Apr 2020 00:04:42 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 055/245] btrfs: ensure that a DUP or RAID1 block group has exactly two stripes In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.83-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Thumshirn commit 349ae63f40638a28c6fce52e8447c2d14b84cc0c upstream. We recently had a customer issue with a corrupted filesystem. When trying to mount this image btrfs panicked with a division by zero in calc_stripe_length(). The corrupt chunk had a 'num_stripes' value of 1. calc_stripe_length() takes this value and divides it by the number of copies the RAID profile is expected to have to calculate the amount of data stripes. As a DUP profile is expected to have 2 copies this division resulted in 1/2 = 0. Later then the 'data_stripes' variable is used as a divisor in the stripe length calculation which results in a division by 0 and thus a kernel panic. When encountering a filesystem with a DUP block group and a 'num_stripes' value unequal to 2, refuse mounting as the image is corrupted and will lead to unexpected behaviour. Code inspection showed a RAID1 block group has the same issues. Fixes: e06cd3dd7cea ("Btrfs: add validadtion checks for chunk loading") Reviewed-by: Qu Wenruo Reviewed-by: Nikolay Borisov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Ben Hutchings --- fs/btrfs/volumes.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -5884,10 +5884,10 @@ static int btrfs_check_chunk_valid(struc } if ((type & BTRFS_BLOCK_GROUP_RAID10 && sub_stripes != 2) || - (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes < 1) || + (type & BTRFS_BLOCK_GROUP_RAID1 && num_stripes != 2) || (type & BTRFS_BLOCK_GROUP_RAID5 && num_stripes < 2) || (type & BTRFS_BLOCK_GROUP_RAID6 && num_stripes < 3) || - (type & BTRFS_BLOCK_GROUP_DUP && num_stripes > 2) || + (type & BTRFS_BLOCK_GROUP_DUP && num_stripes != 2) || ((type & BTRFS_BLOCK_GROUP_PROFILE_MASK) == 0 && num_stripes != 1)) { btrfs_err(root->fs_info,