From: "Serge E. Hallyn" <serge@hallyn.com>
To: Bastian Blank <bastian@waldi.eu.org>,
"Serge E. Hallyn" <serge@hallyn.com>,
containers@lists.linux-foundation.org,
kernel list <linux-kernel@vger.kernel.org>,
LSM <linux-security-module@vger.kernel.org>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <kees.cook@canonical.com>,
Alexey Dobriyan <adobriyan@gmail.com>,
Michael Kerrisk <mtk.manpages@gmail.com>
Subject: Re: [PATCH 6/7] user namespaces: convert all capable checks in kernel/sys.c
Date: Tue, 11 Jan 2011 05:27:59 +0000 [thread overview]
Message-ID: <20110111052759.GA24970@mail.hallyn.com> (raw)
In-Reply-To: <20110110215937.GB21351@wavehammer.waldi.eu.org>
Quoting Bastian Blank (bastian@waldi.eu.org):
> On Mon, Jan 10, 2011 at 09:14:07PM +0000, Serge E. Hallyn wrote:
> > - if (pcred->uid != cred->euid &&
> > - pcred->euid != cred->euid && !capable(CAP_SYS_NICE)) {
> > + if (pcred->user->user_ns != cred->user->user_ns &&
> > + pcred->uid != cred->euid &&
> > + pcred->euid != cred->euid &&
> > + !ns_capable(pcred->user->user_ns, CAP_SYS_NICE)) {
>
> I don't think this is correct. This would not error out if the both
> userns are the same. Because the same patern (check uid if same userns,
> otherwise only capability) shows up in several parts of the code, maybe
> this should be factored out.
Yeah, I'd really like to factor this out because it shows up everywhere
and I have to think about it every time I look at it. But each time it
shows up, the uids being compared slightly change. There must be some
clever way of doing it, hopefully it'll fall out soon.
Eric's ns_capable() has already simplified this quite a bit - which is
part of why I've sometimes not been thinking about it right, it's now
simpler than it used to be :)
thanks,
-serge
next prev parent reply other threads:[~2011-01-11 5:26 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-01-10 21:11 userns: targeted capabilities v3 Serge E. Hallyn
2011-01-10 21:13 ` [PATCH 1/7] Add a user_namespace as creator/owner of uts_namespace Serge E. Hallyn
2011-01-10 21:13 ` [PATCH 2/7] security: Make capabilities relative to the user namespace Serge E. Hallyn
2011-01-10 21:13 ` [PATCH 3/7] allow sethostname in a container Serge E. Hallyn
2011-01-10 21:13 ` [PATCH 4/7] allow killing tasks in your own or child userns Serge E. Hallyn
2011-01-10 21:52 ` Bastian Blank
2011-01-10 22:51 ` Serge Hallyn
2011-01-10 23:23 ` Bastian Blank
2011-01-11 1:31 ` Serge E. Hallyn
2011-01-14 14:50 ` Bastian Blank
2011-01-15 0:31 ` Serge E. Hallyn
2011-01-15 11:30 ` Bastian Blank
2011-01-15 14:12 ` Serge E. Hallyn
2011-01-11 4:22 ` Oren Laadan
2011-01-11 4:32 ` Serge E. Hallyn
2011-01-10 21:13 ` [PATCH 5/7] Allow ptrace from non-init user namespaces Serge E. Hallyn
2011-01-10 21:14 ` [PATCH 6/7] user namespaces: convert all capable checks in kernel/sys.c Serge E. Hallyn
2011-01-10 21:59 ` Bastian Blank
2011-01-10 22:56 ` Serge Hallyn
2011-01-11 5:27 ` Serge E. Hallyn [this message]
2011-01-14 15:02 ` Bastian Blank
2011-01-10 21:14 ` [PATCH 7/7] user namespaces: convert several capable() calls Serge E. Hallyn
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