From: ebiederm@xmission.com (Eric W. Biederman)
To: Serge Hallyn <serge@hallyn.com>
Cc: linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
containers@lists.linux-foundation.org, dhowells@redhat.com
Subject: Re: [PATCH 02/14] allow root in container to copy namespaces
Date: Wed, 27 Jul 2011 16:14:30 -0700 [thread overview]
Message-ID: <m1hb67fh9l.fsf@fess.ebiederm.org> (raw)
In-Reply-To: <1311706717-7398-3-git-send-email-serge@hallyn.com> (Serge Hallyn's message of "Tue, 26 Jul 2011 18:58:25 +0000")
Serge Hallyn <serge@hallyn.com> writes:
> From: Serge E. Hallyn <serge.hallyn@canonical.com>
>
> Othewise nested containers with user namespaces won't be possible.
>
> It's true that user namespaces are not yet fully isolated, but for
> that same reason there are far worse things that root in a child
> user ns can do. Spawning a child user ns is not in itself bad.
>
> This patch also allows setns for root in a container:
> @Eric Biederman: are there gotchas in allowing setns from child
> userns?
Yes. We need to ensure that the target namespaces are namespaces
that have been created in from user_namespace or from a child of this
user_namespace.
Aka we need to ensure that we have CAP_SYS_ADMIN for the new namespace.
Eric
> Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
> Cc: Eric W. Biederman <ebiederm@xmission.com>
> ---
> kernel/fork.c | 4 ++--
> kernel/nsproxy.c | 6 +++---
> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/kernel/fork.c b/kernel/fork.c
> index 17bf7c8..22d0cf0 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1473,8 +1473,8 @@ long do_fork(unsigned long clone_flags,
> /* hopefully this check will go away when userns support is
> * complete
> */
> - if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SETUID) ||
> - !capable(CAP_SETGID))
> + if (!nsown_capable(CAP_SYS_ADMIN) || !nsown_capable(CAP_SETUID) ||
> + !nsown_capable(CAP_SETGID))
> return -EPERM;
> }
>
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index 9aeab4b..f50542d 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -134,7 +134,7 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
> CLONE_NEWPID | CLONE_NEWNET)))
> return 0;
>
> - if (!capable(CAP_SYS_ADMIN)) {
> + if (!nsown_capable(CAP_SYS_ADMIN)) {
> err = -EPERM;
> goto out;
> }
> @@ -191,7 +191,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
> CLONE_NEWNET)))
> return 0;
>
> - if (!capable(CAP_SYS_ADMIN))
> + if (!nsown_capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> *new_nsp = create_new_namespaces(unshare_flags, current,
> @@ -241,7 +241,7 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype)
> struct file *file;
> int err;
>
> - if (!capable(CAP_SYS_ADMIN))
> + if (!nsown_capable(CAP_SYS_ADMIN))
> return -EPERM;
>
> file = proc_ns_fget(fd);
next prev parent reply other threads:[~2011-07-27 23:14 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-26 18:58 [PATCH 0/14] user namespaces v2: continue targetting capabilities Serge Hallyn
2011-07-26 18:58 ` [PATCH 01/14] add Documentation/namespaces/user_namespace.txt Serge Hallyn
2011-07-26 20:22 ` Randy Dunlap
2011-07-26 20:29 ` David Howells
2011-07-29 17:25 ` [PATCH 01/14] add Documentation/namespaces/user_namespace.txt (v3) Serge E. Hallyn
2011-07-27 15:38 ` [PATCH 01/14] add Documentation/namespaces/user_namespace.txt Serge E. Hallyn
2011-07-27 16:02 ` Randy Dunlap
2011-07-26 18:58 ` [PATCH 02/14] allow root in container to copy namespaces Serge Hallyn
2011-07-27 23:14 ` Eric W. Biederman [this message]
2011-07-28 2:13 ` Serge E. Hallyn
2011-07-29 17:27 ` [PATCH 02/14] allow root in container to copy namespaces (v3) Serge E. Hallyn
2011-08-01 22:25 ` Eric W. Biederman
2011-08-02 14:08 ` Serge E. Hallyn
2011-08-02 22:03 ` Eric W. Biederman
2011-08-04 22:01 ` Serge E. Hallyn
2011-07-26 18:58 ` [PATCH 03/14] keyctl: check capabilities against key's user_ns Serge Hallyn
2011-07-26 18:58 ` [PATCH 04/14] user_ns: convert fs/attr.c to targeted capabilities Serge Hallyn
2011-07-26 18:58 ` [PATCH 05/14] userns: clamp down users of cap_raised Serge Hallyn
2011-07-28 23:23 ` Vasiliy Kulikov
2011-07-28 23:51 ` Serge E. Hallyn
2011-07-26 18:58 ` [PATCH 06/14] user namespace: make each net (net_ns) belong to a user_ns Serge Hallyn
2011-07-26 18:58 ` [PATCH 07/14] user namespace: use net->user_ns for some capable calls under net/ Serge Hallyn
2011-07-26 18:58 ` [PATCH 08/14] af_netlink.c: make netlink_capable userns-aware Serge Hallyn
2011-07-26 18:58 ` [PATCH 09/14] user ns: convert ipv6 to targeted capabilities Serge Hallyn
2011-07-26 18:58 ` [PATCH 10/14] net/core/scm.c: target capable() calls to user_ns owning the net_ns Serge Hallyn
2011-08-04 22:06 ` Serge E. Hallyn
2011-07-26 18:58 ` [PATCH 11/14] userns: make some net-sysfs capable calls targeted Serge Hallyn
2011-07-26 18:58 ` [PATCH 12/14] user_ns: target af_key capability check Serge Hallyn
2011-07-26 18:58 ` [PATCH 13/14] userns: net: make many network capable calls targeted Serge Hallyn
2011-07-26 18:58 ` [PATCH 14/14] net: pass user_ns to cap_netlink_recv() Serge Hallyn
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=m1hb67fh9l.fsf@fess.ebiederm.org \
--to=ebiederm@xmission.com \
--cc=containers@lists.linux-foundation.org \
--cc=dhowells@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=serge@hallyn.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox