[lxc-users] sysctl -p no longer allowed in container
dank at kegel.com
Tue Apr 29 20:56:56 UTC 2014
This may be a jinxed machine. I installed it from trusty beta 2. I
should probably try again with the released version.
Inside the container:
/proc/self/attr/current says lxc-container-default (enforce)
There's no line in syslog, and I don't have an audit/audit.log.
open("/proc/sys/kernel/sem", O_WRONLY|O_CREAT|O_TRUNC, 0666) = -1 EACCESS
apt-cache policy apparmor says it's not installed.
Installing it says it won't start inside a container.
And all this in spite of the container having apparmor off, and being able to
happily write to it there.
I haven't been able to set that parameter in the container yet today :-(
/var/log/upstart/procps.log in the container also shows
sysctl: permission denied on key 'kernel.sem'
(since I put that setting into /etc/sysctl.conf)
And apparmor_status inside lxc fails with permission denied on
(which doesn't seem too surprising, but what do I know...)
On Tue, Apr 29, 2014 at 1:25 PM, Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
> Quoting Dan Kegel (dank at kegel.com):
>> OK, it's not as benign as I thought; I can't even do the setting in the host
>> without disabling apparmor. So I guess I should file a bug against
> Hm? I don't have that problem... what is in /proc/self/attr/current?
> Does /var/log/audit/audit.log or /var/log/syslog show an apparmor
> denial for it? what does strace show?
>> ubuntu 14.04 apparmor. Thanks!
>> - Dan
>> On Tue, Apr 29, 2014 at 12:17 PM, Dan Kegel <dank at kegel.com> wrote:
>> > Think I should file a bug? (And against what?)
>> > - Dan
>> > On Tue, Apr 29, 2014 at 12:15 PM, Serge Hallyn <serge.hallyn at ubuntu.com> wrote:
>> >> Quoting Dan Kegel (dank at kegel.com):
>> >>> My scripts were (unwisely) expecting to be able to do things like
>> >>> echo "kernel.sem = 250 65536 32 32768" | sudo tee -a /etc/sysctl.conf
>> >>> sudo /sbin/sysctl -p
>> >>> inside the container. Tsk. I seem to have gotten away with it in
>> >>> Ubuntu 12.04, but Ubuntu 14.04 complains
>> >>> + sudo /sbin/sysctl -p
>> >>> sysctl: permission denied on key 'kernel.sem'
>> >>> That makes sense -- containers shouldn't be able to tweak kernel parameters.
>> >>> So now I'm rejiggering my scripts to do that outside the container.
>> >>> Onwards!
>> >> Hm, actually i think that one should be fine. The apparmor profile
>> >> excempts /proc/sys/kernel/shm*, and it looks like /proc/sys/kernel/sem
>> >> should also be allowed as it looks to be correctly namespaced - i.e
>> >> the container won't affect the host's settings.
>> >> -serge
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