[Samba] Debian Buster, bind_dlz, and apparmor

Rowland Penny rpenny at samba.org
Tue Nov 28 17:56:48 UTC 2017


On Tue, 28 Nov 2017 11:24:58 -0600
Dale Schroeder <dale at BriannasSaladDressing.com> wrote:

> On 11/28/2017 11:11 AM, Robert Wooden wrote:
> > Dale,
> >
> > Been using Ubuntu server for years in my AD. Discovered a long time 
> > ago that apparmor is not needed for a server. (Someone is probably 
> > going to argue the other that is should be but . . .)
> >
> > Do not quote me but, I have read that AppArmor is intended more for
> > a desktop environment. I have always disabled and then removed
> > AppArmor and have never had any issues. Of course I am behind a
> > hardware firewall so, hopefully, no exposure to any unwanted
> > attacks.
> >
> > All my servers work fine without AppArmor.
> >
> > As an Ubuntu user, my 2 cents . . .
> >
> > On Tue, Nov 28, 2017 at 10:55 AM, Dale Schroeder via samba 
> > <samba at lists.samba.org <mailto:samba at lists.samba.org>> wrote:
> >
> >     On 11/28/2017 9:02 AM, Rowland Penny wrote:
> >
> >         On Tue, 28 Nov 2017 08:37:22 -0600
> >         Dale Schroeder via samba <samba at lists.samba.org
> >         <mailto:samba at lists.samba.org>> wrote:
> >
> >
> >             On 11/28/2017 2:38 AM, Rowland Penny via samba wrote:
> >
> >                 On Mon, 27 Nov 2017 14:53:32 -0600
> >                 Dale Schroeder via samba <samba at lists.samba.org
> >                 <mailto:samba at lists.samba.org>> wrote:
> >
> >                     Last week, Debian testing (Buster) added
> > apparmor to the list of
> >                     dependencies for its latest kernel release,
> >                     apparently because
> >                     systemd needs it.  Recently, I noticed my first
> >                     casualty - bind9 -
> >                     due to apparmor failures with bind_dlz.
> >
> >                     Knowing next to nothing about apparmor, what is
> >                     needed to fix this,
> >                     and what further info do you need from me?
> >
> >                     Thanks,
> >                     Dale
> >
> >                 I cannot seem to find a debian kernel that has a
> >                 dependency on
> >                 apparmor, can you provide a link ?
> >
> >                 Even if debian is making the kernel depend on
> > apparmor (by the way,
> >                 does Linus know about this  ?), this isn't a Samba
> >                 problem, it is an
> >                 apparmor one.
> >
> >                 Rowland
> >
> >             Rowland,
> >
> >             Thanks for responding.
> >
> >             From
> >             http://metadata.ftp-master.debian.org/changelogs/main/l/linux/linux_4.13.13-1_changelog
> >             <http://metadata.ftp-master.debian.org/changelogs/main/l/linux/linux_4.13.13-1_changelog>
> >
> >             [ Ben Hutchings ]
> >                 * linux-image: Recommend apparmor, as systemd units
> >             with an
> >             AppArmor profile will fail without it (Closes: #880441)
> >
> >             So, although the word "recommend" implies that one has a
> >             choice, in
> >             reality, the kernel upgrade would not proceed without
> >             installing
> >             apparmor.
> >
> >         Then it is a bug, depend means it will be installed,
> > recommend means
> >         what it says, it is recommended to install it, but you do
> > not need to.
> >
> >             I suppose it would be possible to disable, but assuming
> >             the systemd
> >             warning is a harbinger of things to come, it seemed best
> >             to me to
> >             figure it out now.  I know systemd is not your thing,
> > and I am inclined to agree; however, Debian sees it otherwise,
> >             leaving me to
> >             deal with it.
> >
> >         Easier way out of this, stop using debian and use Devuan
> > instead.
> >
> >             I asked here because there is a wiki section devoted to
> >             the topic -
> >             https://wiki.samba.org/index.php/BIND9_DLZ_AppArmor_and_SELinux_Integration
> >             <https://wiki.samba.org/index.php/BIND9_DLZ_AppArmor_and_SELinux_Integration>
> >
> >             Thus far, SELinux has not been forced by Debian.
> >             Regardless, since
> >             the apparmor install, I have not been able to get Bind9
> > to start if
> >             bind_dlz is enabled.
> >
> >         As I said, apparmor has nothing to do with Samba, the same
> >         goes for
> >         selinux and, in my opinion, they should figure out how to
> > work with
> >         Samba, not the other way round. The page on the wiki is
> >         supplied as a
> >         service, but Samba has no real way to know if the settings
> > are correct,
> >         it relies on feedback from users.
> >
> >         Rowland
> >
> >     Likewise, I had hoped some of the Ubuntu or Red Hat-derived OS
> >     users would chime in.  I had previously tried several different
> >     incantations with no luck.  Just now, I found this, taken from
> >     https://2stech.ca/index.php/linux/linuxtutotials/tutorials/234-samba-active-directory-with-bind-dns-backend-on-ubuntu-1404
> >     <https://2stech.ca/index.php/linux/linuxtutotials/tutorials/234-samba-active-directory-with-bind-dns-backend-on-ubuntu-1404>
> >
> >       /var/lib/samba/private/krb5.co <http://krb5.co>nf r,
> >       /var/lib/samba/private/dns.keytab r,
> >       /var/lib/samba/private/named.conf r,
> >       /var/lib/samba/private/dns/** rwk,
> >       /usr/lib/x86_64-linux-gnu/samba/** m,
> >       /usr/lib/x86_64-linux-gnu/ldb/modules/ldb/** m,
> >
> >     This dated recipe works for me where newer ones did not. BIND
> >     9.10.6 is happy again.  YMMV
> >
> >     Dale
> >
> >     -- 
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> > the instructions: https://lists.samba.org/mailman/options/samba
> >     <https://lists.samba.org/mailman/options/samba>
> >
> >
> >
> >
> > -- 
> > Thank you. Bob Wooden
> >
> > 615.885.2846www.donelsontrophy.com <http://www.donelsontrophy.com>
> >
> > "Everyone deserves an award!!"
> Bob,
> 
> I agree with everything you say and would rather not have it, but if 
> Debian's kernel maintainers are correct in that more systemd service 
> files will require apparmor, what other choice do I have but to learn 
> it?  I am not sure why Debian has decided to follow the
> systemd/apparmor path, but I guess I get to go along for the ride. If
> it becomes to onerous, I may have to do as you did and remove it.
> BTW, the apparmor file for ntp worked out of the box, no
> modifications on my part required.
> 
> Thanks,
> Dale

The problem is that debian has fixed only half of the problem, yes
recommend apparmor by all means, but they also need to fix systemd
units to NOT fail if apparmor isn't installed, after all, apparmor is a
'recommend' and not a 'dependency'. If some systemd units fail if
apparmor isn't installed, then this is, undoubtedly, a bug.

Mind you, all of this is irrelevant to me, I do not use systemd ;-)
 
Rowland
 



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