From: "Serge E. Hallyn" <serge@hallyn.com>
To: Bastian Blank <bastian@waldi.eu.org>,
Serge Hallyn <serge.hallyn@canonical.com>,
"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 4/7] allow killing tasks in your own or child userns
Date: Tue, 11 Jan 2011 01:31:52 +0000 [thread overview]
Message-ID: <20110111013152.GA23860@mail.hallyn.com> (raw)
In-Reply-To: <20110110232335.GA27029@wavehammer.waldi.eu.org>
Quoting Bastian Blank (bastian@waldi.eu.org):
> On Mon, Jan 10, 2011 at 04:51:51PM -0600, Serge Hallyn wrote:
> > Quoting Bastian Blank (bastian@waldi.eu.org):
> > > Isn't that equal to this?
> > >
> > > if (ns_capable(tcred->user->user_ns, CAP_KILL))
> > > return 1;
> > >
> > > if (cred->user->user_ns == tcred->user->user_ns &&
> > > (cred->euid == tcred->suid ||
> > > cred->euid == tcred->uid ||
> > > cred->uid == tcred->suid ||
> > > cred->uid == tcred->uid))
> > > return 1;
> > >
> > > return 0;
> > >
> > > I would consider this much easier to read.
> >
> > Unfortunately, it's actually not equivalent. when capable()
> > returns success, then it sets the current->flags |= PF_SUPERPRIV.
> > If permission is granted based on userids and the capability
> > isn't needed, then we don't want to needlessly set PF_SUPERPRIV.
>
> Well, then switch the two if-clauses.
hup, will do, much nicer, thanks.
> What is this flag used for anyway? I only see it used in the accounting
> stuff, and if every user can get it, it is not longer useful.
hm, I'm not sure... maybe noone is using it!
next prev parent reply other threads:[~2011-01-11 1:30 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 [this message]
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
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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