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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 F14C8C742A2 for ; Thu, 11 Jul 2019 23:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD99620872 for ; Thu, 11 Jul 2019 23:14:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728721AbfGKXOt (ORCPT ); Thu, 11 Jul 2019 19:14:49 -0400 Received: from mailgw-02.dd24.net ([193.46.215.43]:41904 "EHLO mailgw-02.dd24.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726207AbfGKXOt (ORCPT ); Thu, 11 Jul 2019 19:14:49 -0400 X-Greylist: delayed 490 seconds by postgrey-1.27 at vger.kernel.org; Thu, 11 Jul 2019 19:14:48 EDT Received: from mailpolicy-01.live.igb.homer.key-systems.net (mailpolicy-02.live.igb.homer.key-systems.net [192.168.1.27]) by mailgw-02.dd24.net (Postfix) with ESMTP id 724355FDE9 for ; Thu, 11 Jul 2019 23:06:37 +0000 (UTC) X-Virus-Scanned: Debian amavisd-new at mailpolicy-02.live.igb.homer.key-systems.net Received: from smtp.dd24.net ([192.168.1.36]) by mailpolicy-01.live.igb.homer.key-systems.net (mailpolicy-02.live.igb.homer.key-systems.net [192.168.1.25]) (amavisd-new, port 10236) with ESMTP id v22p-4GrnZAL for ; Thu, 11 Jul 2019 23:06:35 +0000 (UTC) Received: from heisenberg.fritz.box (ppp-46-244-248-28.dynamic.mnet-online.de [46.244.248.28]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.dd24.net (Postfix) with ESMTPSA for ; Thu, 11 Jul 2019 23:06:35 +0000 (UTC) Message-ID: Subject: Re: "btrfs: harden agaist duplicate fsid" spams syslog From: Christoph Anton Mitterer To: linux-btrfs@vger.kernel.org Date: Fri, 12 Jul 2019 01:06:34 +0200 In-Reply-To: References: <5d8baf80-4fb3-221f-5ab4-e98a838f63e1@cobb.uk.net> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.30.5-1.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org I'm also seeing these since quite a while on Debian sid: Jul 11 13:33:56 heisenberg kernel: BTRFS info (device dm-0): device fsid 60[...]3c devid 1 moved old:/dev/mapper/system new:/dev/dm-0 Jul 11 13:33:56 heisenberg kernel: BTRFS info (device dm-0): device fsid 60[...]3c devid 1 moved old:/dev/dm-0 new:/dev/mapper/system Jul 11 23:43:35 heisenberg kernel: BTRFS info (device dm-0): device fsid 60[...]3c devid 1 moved old:/dev/mapper/system new:/dev/dm-0 Jul 11 23:43:35 heisenberg kernel: BTRFS info (device dm-0): device fsid 60[...]3c devid 1 moved old:/dev/dm-0 new:/dev/mapper/system In my case it's a simply dm-crypt layer below the fs. Some years ago, there was a longer thread on this list about the fragility of btrfs with respect to accidentally or intentionally colliding UUIDs. IIRC there were quite some concerns that this could have even a big security impact when an attacker e.g. plugs in a device with a certain UUID and the kernel or userland automatically adds or somehow else uses such device (just by UUID). Back then it was said this would be looked into... has anything happened there? Cheers, Chris.