[Devel] [PATCH rh7] signal/ve: allow to send signal from another ve namespace

[Stanislav Kinsburskiу]

12 нояб. 2015 г. 17:51 пользователь Andrey Wagin <avagin at gmail.com> написал:
>
> 2015-11-12 19:41 GMT+03:00 Stanislav Kinsburskiy <skinsbursky at odin.com>: 
> > 
> > 
> > 12.11.2015 17:11, Andrey Ryabinin пишет: 
> > 
> >> 
> >> On 11/12/2015 07:08 PM, Stanislav Kinsburskiy wrote: 
> >>> 
> >>> 
> >>> 12.11.2015 16:47, Andrey Ryabinin пишет: 
> >>>> 
> >>>> On 11/12/2015 05:59 PM, Stanislav Kinsburskiy wrote: 
> >>>>> 
> >>>>> 12.11.2015 15:53, Andrey Wagin пишет: 
> >>>>>> 
> >>>>>> 2015-11-12 17:46 GMT+03:00 Stanislav Kinsburskiу 
> >>>>>> <skinsbursky at odin.com>: 
> >>>>>>> 
> >>>>>>> 12 нояб. 2015 г. 15:14 пользователь Andrey Ryabinin 
> >>>>>>> <aryabinin at virtuozzo.com> написал: 
> >>>>>>>> 
> >>>>>>>> CRIU sends SIGKILL to container's init process as a part of 
> >>>>>>>> cleanup process if restoring failed. 
> >>>>>>>> CRIU does this from a different ve, which is currently not allowed 
> >>>>>>>> without any apparent reason. 
> >>>>>>> 
> >>>>>>> The reason looks very clear to me: improve namespaces isolation. 
> >>>>>>> It espesially applies to killing child reaper of another ve. 
> >>>>>>> You throwed away this check, and now it's possible to kill one 
> >>>>>>> container from another one. 
> >>>>>>> Or I'm missing somethig? 
> >>>>>> 
> >>>>>> Each container has its own pidns, so you can't kill anyone who isn't 
> >>>>>> in this pidns. 
> >>>>> 
> >>>>> So how CRIU sends kill signal from one ve to another then? 
> >>>>> 
> >>>> AFAIK, CRIU creates it's own ve namespace, but it still operates in root 
> >>>> pid namespace. 
> >>> 
> >>> Hmm, ok. 
> >>> Then nothing against this patch. 
> >>> The only thing I'm curios: for how long we have this patch? Pid 
> >>> namespaces are used in OpenVZ for at least last 6 years (probably more). 
> >>> When this checks appeared? Maybe there was another reason, which is just 
> >>> not obvious so far? 
> >> 
> >> I suspect that it was just blindly ported from 2.6: 
> >> 
> >> commit fd3207d650434ac82f2c897cadd5607e67f2c274 
> >> Author: Kirill Tkhai <ktkhai at parallels.com> 
> >> Date:   Fri Oct 10 19:35:02 2014 +0400 
> >> 
> >>      ve: Ignore signals from wrong ve 
> >>           Port sig_ve_ignored(). 
> >>           This is a part of 74-diff-ve-mix-combined. 
> >>           https://jira.sw.ru/browse/PSBM-17903 
> >>           Signed-off-by: Kirill Tkhai <ktkhai at parallels.com> 
> > 
> > 
> > That's for sure. 
> > My question was about origins of this patch. 
> > Thanks to Vasiliy: 
> > 
> > RCS file: 
> > /cvs/Virtuozzo/kernel-patches/2.6.18-rhel5/diff-ve-init-signals-20070514,v 
> > Working file: diff-ve-init-signals-20070514 
> > head: 1.1 
> > branch: 
> > locks: strict 
> > access list: 
> > symbolic names: 
> > keyword substitution: o 
> > total revisions: 1;    selected revisions: 1 
> > description: 
> > ---------------------------- 
> > revision 1.1 
> > date: 2007/05/18 13:24:17;  author: dev;  state: Exp; 
> > Patch from Denis Lunev <den at openvz.org> 
> > [VE] VE init signal delivery reworked to be similar to host 
> > Prevent VE init from receiving unexpected signals sent from VE 
> > including fatal ones. Signals sent from VE0 are still allowed, 
> > e.g. for fast VE stop. 
> > Fix for sys_reboot called from VE to force VE death 
> > (SIGKILL is sent in the context of VE). 
> > 
> > http://bugzilla.openvz.org/show_bug.cgi?id=533 
> > 
> > Are you sure, that you are not braking the logic, this patch introduced in 
> > past? 
>
>
>
> [root at fc22-vm ~]# unshare --fork -p 
> [root at fc22-vm ~]# kill -9 1 
> [root at fc22-vm ~]# kill -9 1 
> [root at fc22-vm ~]# kill -9 1 
> [root at fc22-vm ~]# kill -9 1 
> [root at fc22-vm ~]# kill -USR1 1 
> [root at fc22-vm ~]# kill -USR1 1 
> [root at fc22-vm ~]# 
>
> > 

 Ok then. Probably, this patch should be ported to rhel6 as well.