From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Thu, 19 Nov 2020 13:44:36 -0500 From: Vivek Goyal Message-ID: <20201119184436.GC3300@redhat.com> References: <0503b244-b426-0779-7b9e-ff63dfa1165c@gmail.com> <20201119181635.GA3300@redhat.com> <04959049-62bf-c7dc-70b5-aacbc649c474@gmail.com> <20201119183841.GB3300@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Disposition: inline Content-Transfer-Encoding: quoted-printable In-Reply-To: <20201119183841.GB3300@redhat.com> Subject: Re: [Virtio-fs] restorcon/SELinux virtiofs question List-Id: Development discussions about virtio-fs List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Harry G. Coin" Cc: virtio-fs@redhat.com On Thu, Nov 19, 2020 at 01:38:41PM -0500, Vivek Goyal wrote: > On Thu, Nov 19, 2020 at 12:27:20PM -0600, Harry G. Coin wrote: > >=20 > > On 11/19/20 12:16 PM, Vivek Goyal wrote: > > > On Thu, Nov 19, 2020 at 10:52:51AM -0600, Harry G. Coin wrote: > > >> Hello virtiofs team.=C2=A0 I need clarification about a 'restorecon'= selinux > > >> guest giving an 'operation not supported' response. > > >> > > >> If the host fs is btrfs (with xattr enabled in virtiofsd) but not > > >> running SELinux, > > > I suspect that on host setxattr(security.selinux) is failing with=20 > > > "operation not supported".=20 > > > > > > What do you mean by host "not running SELinux". SElinux is not compil= ed > > > in? Or it is disabled or in passive mode? > > > > > > Is it working with filesystems other than btrfs, say ext4 or xfs. > > > > > > Now qemu supports xattr remapping. You might want to run virtiofsd > > > to remap security.selinux. I think that might get you going till > > > the root cause of the issue is found. > > > > > > Vivek > >=20 > > Thank you for the focus.=A0=A0 The host os in this instance is not from= the > > fedora/rhel/centos world with selinux running.=A0 My case is a debian > > sourced distro (ubuntu).=A0 That world uses 'apparmor' by default, not > > selinux.=A0=A0 I think it's reasonable to suppose there are a lot of se= rvers > > out there not running selinux that have lots of vms running on them, not > > all using virtiofs.=A0 There should be a documented way to allow the > > 'restorcon' command on one of many guests on such hosts to work.=A0 I > > suppose to wrap this up: > >=20 > > For the future readers who got here by searching,=A0 could you give the > > first kernel version that supports a non-selinux host supporting an > > selinux enabled guest and the virtiofsd command line necessary to get > > the restorecon command to work normally? >=20 > I don't know yet. Because I don't know what's the root cause of the > issue. >=20 > The way you are explaining it, looks like host kernel somehow is > blocking setxattr(security.selinux). And I have no idea why. Is it > apparmor or something else. >=20 > If no selinux module is loaded on host, then as long as virtiofsd > process has CAP_SYS_ADMIN, it should be able to set security.selinux. >=20 > "Operation not supported" means error "EOPNOTSUP". I am assuming > you are running virtiofsd with "-o xattr" to make sure virtiofsd > supports xattr. If that's the case somehow kernel is returning > "EOPNOTSUP". >=20 > Can you run virtiofsd with debug option -d and try to install that > package in guest and capture outout of virtiofsd and post here. It > might confirm that host kernel is returning error. I tried doing "chcon unconfined_u:object_r:admin_home_t:s0 bar.txt"=20 on a file in virtiofs and got "Operation not supported". I think guest kernel failed this. Will need to debug further. Vivek