From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id 26133BB9B2 for ; Mon, 25 Mar 2024 18:30:54 +0100 (CET) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 07EF89451 for ; Mon, 25 Mar 2024 18:30:24 +0100 (CET) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS for ; Mon, 25 Mar 2024 18:30:23 +0100 (CET) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id 34D2B41FBE for ; Mon, 25 Mar 2024 18:30:23 +0100 (CET) Message-ID: Date: Mon, 25 Mar 2024 18:30:22 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: Fiona Ebner , Proxmox VE development discussion References: <20240108135456.74684-1-f.schauer@proxmox.com> From: Filip Schauer In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL -0.089 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pve-devel] [PATCH container] fix #5160: fix move_mount regression for mount point hotplug X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Mar 2024 17:30:54 -0000 On 25/03/2024 11:29, Fiona Ebner wrote: > Am 08.01.24 um 14:54 schrieb Filip Schauer: >> Set up an Apparmor profile to allow moving mounts for mount point >> hotplug. >> >> This fixes a regression caused by >> kernel commit 157a3537d6 ("apparmor: Fix regression in mount mediation") >> >> The commit introduced move_mount mediation, which now requires >> move_mount to be allowed in the Apparmor profile. Although it is allowed >> for most paths in the /usr/bin/lxc-start profile, move_mount is called >> with a file descriptor instead of a path in mountpoint_insert_staged, >> thus it is not affected by the allow rules in >> /etc/apparmor.d/abstractions/lxc/container-base. >> > Would it be difficult/impossible for us to do it path-based instead? A path-based approach would not work as things are right now, since we use the file descriptor to issue a move_mount from within the container's namespace, where we cannot access the staging directory with a path. >> To fix this, introduce a new Apparmor profile to allow move_mount on >> every mount, specifically for mount point hotplug. >> >> Signed-off-by: Filip Schauer > Tested-by: Fiona Ebner > > Fixes the issue and makes hotplug work again :) > > However, I did run into one minor thing (number 1 below), but not sure > if it can be improved. Except the part about the undef warning which is > pre-existing. Another pre-existing issue I ran into is number 2 below, > should also be investigated, but is not caused by this patch. > > 1. > > For an already running container, I got > >> mp0: unable to hotplug mp0: failed to change apparmor profile: > after installing the patched pve-container package and attempting to > hotplug. Maybe that's expected and no big deal, because hotplug already > didn't work. > > Checking in the journal, it's: > >> AVC apparmor="DENIED" operation="change_profile" class="file" info="label not found" error=-2 profile="unconfined" name="pve-container-mounthotplug" pid=99919 comm=7076656461656D6F6E20776F726B65 This happens because the new apparmor profile "pve-container-mounthotplug" is not loaded correctly in postinst. This is fixed in v2. >> Use of uninitialized value in numeric ne (!=) at /usr/share/perl5/PVE/LXC.pm line 1978. > The latter warning seems to be pre-existing for the syswrite comparison > below: > >> @@ -1974,7 +1974,7 @@ sub mountpoint_hotplug :prototype($$$$$) { >> my $dir = get_staging_mount_path($opt); >> >> # Now switch our apparmor profile before mounting: >> - my $data = 'changeprofile /usr/bin/lxc-start'; >> + my $data = 'changeprofile pve-container-mounthotplug'; >> if (syswrite($aa_fd, $data, length($data)) != length($data)) { >> die "failed to change apparmor profile: $!\n"; >> } > > But then $! should be set according to 'perldoc -f syswrite' which it > wasn't telling from my quoted error message above ¯\_(ツ)_/¯ > >> Returns the number of bytes actually >> written, or "undef" if there was an error (in this case the >> errno variable $! is also set) A fix for the warning is in the v2. > 2. > > After shutdown+start, the hotplug worked as expected. Played around a > bit more and something strange happened with LVM as the storage: While > it worked the first time, when I shut down the container, detached the > mount point, started again and then tried to hot-plug, I got: > mp1: unable to hotplug mp1: command 'mount /dev/lvm/vm-129-disk-1 > /var/lib/lxc/.pve-staged-mounts/mp1' failed: exit code 32 > > Doesn't seem to happen with ZFS or directory storage and starting with > the mount point pre-attached also worked fine with previously written > files still there. > > Also booted into 6.2.16-20-pve, installed unpatched pve-container and it > seems the issue was already present then.