From: Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
To: Andrey Vagin <avagin-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>
Cc: linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Andrey Vagin <avagin-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Andrew Morton
<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
"Eric W. Biederman"
<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
Cyrill Gorcunov
<gorcunov-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>,
Pavel Emelyanov <xemul-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>,
Serge Hallyn
<serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>,
Rob Landley <rob-VoJi6FS/r0vR7s880joybQ@public.gmane.org>
Subject: Re: [PATCH] [RFC] mnt: add ability to clone mntns starting with the current root
Date: Tue, 7 Oct 2014 14:33:39 +0100 [thread overview]
Message-ID: <20141007133339.GH7996@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20141007133039.GG7996-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
On Tue, Oct 07, 2014 at 02:30:40PM +0100, Al Viro wrote:
> On Tue, Oct 07, 2014 at 04:12:57PM +0400, Andrey Vagin wrote:
> > Another problem is that rootfs can't be hidden from a container, because
> > rootfs can't be moved or umounted.
>
> ... which is a bug in mntns_install(), AFAICS.
Ability to get to exposed rootfs, that is.
> > Here is an example how to get access to rootfs:
> > fd = open("/proc/self/ns/mnt", O_RDONLY)
> > umount2("/", MNT_DETACH);
> > setns(fd, CLONE_NEWNS)
> >
> > rootfs may contain data, which should not be avaliable in CT-s.
>
> Indeed.
... and it looks like the above is what your mangled reproducer in previous
patch had been made of -
fd = open("/proc/self/ns/mnt", O_RDONLY)
umount2("/", MNT_DETACH);
setns(fd, CLONE_NEWNS)
umount2("/", MNT_DETACH);
IMO what it shows is setns() bug. This "switch root/cwd, no matter what"
is wrong.
WARNING: multiple messages have this Message-ID (diff)
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Andrey Vagin <avagin@openvz.org>
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, Andrey Vagin <avagin@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Pavel Emelyanov <xemul@parallels.com>,
Serge Hallyn <serge.hallyn@canonical.com>,
Rob Landley <rob@landley.net>
Subject: Re: [PATCH] [RFC] mnt: add ability to clone mntns starting with the current root
Date: Tue, 7 Oct 2014 14:33:39 +0100 [thread overview]
Message-ID: <20141007133339.GH7996@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20141007133039.GG7996@ZenIV.linux.org.uk>
On Tue, Oct 07, 2014 at 02:30:40PM +0100, Al Viro wrote:
> On Tue, Oct 07, 2014 at 04:12:57PM +0400, Andrey Vagin wrote:
> > Another problem is that rootfs can't be hidden from a container, because
> > rootfs can't be moved or umounted.
>
> ... which is a bug in mntns_install(), AFAICS.
Ability to get to exposed rootfs, that is.
> > Here is an example how to get access to rootfs:
> > fd = open("/proc/self/ns/mnt", O_RDONLY)
> > umount2("/", MNT_DETACH);
> > setns(fd, CLONE_NEWNS)
> >
> > rootfs may contain data, which should not be avaliable in CT-s.
>
> Indeed.
... and it looks like the above is what your mangled reproducer in previous
patch had been made of -
fd = open("/proc/self/ns/mnt", O_RDONLY)
umount2("/", MNT_DETACH);
setns(fd, CLONE_NEWNS)
umount2("/", MNT_DETACH);
IMO what it shows is setns() bug. This "switch root/cwd, no matter what"
is wrong.
next prev parent reply other threads:[~2014-10-07 13:33 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-07 12:12 [PATCH] [RFC] mnt: add ability to clone mntns starting with the current root Andrey Vagin
2014-10-07 12:12 ` Andrey Vagin
2014-10-07 13:30 ` Al Viro
[not found] ` <20141007133039.GG7996-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2014-10-07 13:33 ` Al Viro [this message]
2014-10-07 13:33 ` Al Viro
[not found] ` <20141007133339.GH7996-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2014-10-07 19:44 ` Andrew Vagin
2014-10-07 19:44 ` Andrew Vagin
2014-10-07 19:44 ` Andrew Vagin
2014-10-07 20:30 ` Eric W. Biederman
2014-10-07 20:30 ` Eric W. Biederman
2014-10-07 20:46 ` Serge Hallyn
2014-10-07 20:52 ` Eric W. Biederman
2014-10-07 20:52 ` Eric W. Biederman
[not found] ` <87wq8bvbzg.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-07 21:32 ` Serge Hallyn
2014-10-07 21:32 ` Serge Hallyn
2014-10-07 21:42 ` Eric W. Biederman
[not found] ` <87zjd7r1z9.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-07 22:19 ` Andy Lutomirski
2014-10-07 22:19 ` Andy Lutomirski
2014-10-07 22:42 ` Eric W. Biederman
2014-10-07 22:42 ` Eric W. Biederman
[not found] ` <87h9zfpkm3.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-07 22:44 ` Andy Lutomirski
2014-10-07 22:44 ` Andy Lutomirski
2014-10-07 23:42 ` Eric W. Biederman
2014-10-07 23:42 ` Eric W. Biederman
2014-10-07 23:44 ` Andy Lutomirski
2014-10-08 0:20 ` Eric W. Biederman
2014-10-08 0:20 ` Eric W. Biederman
[not found] ` <87vbnvif9e.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-08 0:25 ` Andy Lutomirski
2014-10-08 0:25 ` Andy Lutomirski
[not found] ` <87r3yjy64e.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-07 21:02 ` Andy Lutomirski
2014-10-07 21:02 ` Andy Lutomirski
[not found] ` <CALCETrXgssZfi3BirQ=K7-vrPyEh5AzFX2pF+yj76Ngi0sf7Yw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-07 21:26 ` Eric W. Biederman
2014-10-07 21:26 ` Eric W. Biederman
2014-10-07 21:26 ` Eric W. Biederman
[not found] ` <87siizshav.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-07 21:38 ` Andy Lutomirski
2014-10-07 21:38 ` Andy Lutomirski
[not found] ` <CALCETrWfZwbGCxnUAg0PnM=tN8MGRQkHrJVC42bVF7sdJKXLmw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-07 21:50 ` Eric W. Biederman
2014-10-07 21:50 ` Eric W. Biederman
2014-10-07 21:50 ` Eric W. Biederman
[not found] ` <87zjd7pn0o.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-07 21:52 ` Andy Lutomirski
2014-10-07 21:52 ` Andy Lutomirski
2014-10-07 21:33 ` Serge Hallyn
2014-10-07 21:33 ` Serge Hallyn
[not found] ` <1412683977-29543-1-git-send-email-avagin-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org>
2014-10-07 20:45 ` Eric W. Biederman
2014-10-07 20:45 ` Eric W. Biederman
[not found] ` <87mw97wqvx.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-08 11:08 ` Andrew Vagin
2014-10-08 11:08 ` Andrew Vagin
2014-10-08 11:08 ` Andrew Vagin
[not found] ` <20141008110829.GC24908-yYYamFZzV1regbzhZkK2zA@public.gmane.org>
2014-10-08 15:35 ` Andy Lutomirski
2014-10-08 15:35 ` Andy Lutomirski
[not found] ` <CALCETrX4XrgbQNZZa7=1009KqhJ2gT+VBUkC15+59K9yEiTSbQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-08 19:23 ` Eric W. Biederman
2014-10-08 19:23 ` Eric W. Biederman
2014-10-08 19:23 ` Eric W. Biederman
2014-10-08 19:31 ` Andy Lutomirski
[not found] ` <CALCETrVSxYr=Oa29qHNL-GoifS26U8TfpreGY+KN7g926YgHUw-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-08 21:36 ` Rob Landley
2014-10-08 21:36 ` Rob Landley
2014-10-08 22:01 ` Andy Lutomirski
[not found] ` <CALCETrXapWTiFw2CC1m43fs9yuHuesXxXtmHh-5F3J_bUYeRxg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2014-10-08 23:38 ` Serge Hallyn
2014-10-08 23:38 ` Serge Hallyn
2014-10-08 23:41 ` Andy Lutomirski
2014-10-08 23:41 ` Andy Lutomirski
[not found] ` <87vbnue56f.fsf-JOvCrm2gF+uungPnsOpG7nhyD016LWXt@public.gmane.org>
2014-10-08 21:23 ` Rob Landley
2014-10-08 21:23 ` Rob Landley
2014-10-09 10:29 ` Andrew Vagin
2014-10-09 10:29 ` Andrew Vagin
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