linux-kernel - Re: [lxc-devel] [RFC PATCH 11/11] loop: Allow priveleged operations for root in the namespace which owns a device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 26 May 2014 17:45:36 +0200
From:	Seth Forshee <seth.forshee@...onical.com>
To:	LXC development mailing-list <lxc-devel@...ts.linuxcontainers.org>
Cc:	Jens Axboe <axboe@...nel.dk>,
	Serge Hallyn <serge.hallyn@...onical.com>,
	Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org,
	Marian Marinov <mm@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [lxc-devel] [RFC PATCH 11/11] loop: Allow priveleged operations
 for root in the namespace which owns a device

On Mon, May 26, 2014 at 11:32:05AM -0400, Michael H. Warfield wrote:
> On Mon, 2014-05-26 at 11:16 +0200, Seth Forshee wrote:
> > On Fri, May 23, 2014 at 08:48:25AM +0300, Marian Marinov wrote:
> > > -----BEGIN PGP SIGNED MESSAGE-----
> > > Hash: SHA1
> > > 
> > > One question about this patch.
> > > 
> > > Why don't you use the devices cgroup check if the root user in that namespace is allowed to use this device?
> > > 
> > > This way you can be sure that the root in that namespace can not access devices to which the host system did not gave
> > > him access to.
> 
> > That might be possible, but I don't want to require something on the
> > host to whitelist the device for the container. Then loop would need to
> > automatically add the device to devices.allow, which doesn't seem
> > desirable to me. But I'm not entirely opposed to the idea if others
> > think this is a better way to go.
> 
> I don't see any safe way to avoid it.  The host has to be in control of
> what devices can and can not be accessed by the container.

Hmm, for testing I've been giving access to 7:* block devices since my
containers can't mknod and only see device nodes for loop devices they
have access to, but maybe I'm not being sufficiently paranoid.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/