From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org (Eric W. Biederman) Subject: Re: [RFC PATCH 2/2] capabilities: allow nice if we are privileged Date: Wed, 24 Jul 2013 01:07:53 -0700 Message-ID: <87bo5snzxi.fsf@xmission.com> References: <20130723181606.GA6342@sergelap> <20130723181853.GA7005@sergelap> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20130723181853.GA7005@sergelap> (Serge Hallyn's message of "Tue, 23 Jul 2013 13:18:53 -0500") List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Serge Hallyn Cc: containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: containers.vger.kernel.org Serge Hallyn writes: > We allow task A to change B's nice level if it has a supserset of > B's privileges, or of it has CAP_SYS_NICE. Also allow it if A has > CAP_SYS_NICE with respect to B - meaning it is root in the same > namespace, or it created B's namespace. This patch looks good to me. We already have this logic elsewhere in the kernel so I don't expect this will make things worse. Reviewed-by: "Eric W. Biederman" > Signed-off-by: Serge Hallyn > --- > security/commoncap.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/security/commoncap.c b/security/commoncap.c > index d78b003..ef98b56 100644 > --- a/security/commoncap.c > +++ b/security/commoncap.c > @@ -768,16 +768,16 @@ int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags) > */ > static int cap_safe_nice(struct task_struct *p) > { > - int is_subset; > + int is_subset, ret = 0; > > rcu_read_lock(); > is_subset = cap_issubset(__task_cred(p)->cap_permitted, > current_cred()->cap_permitted); > + if (!is_subset && !ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) > + ret = -EPERM; > rcu_read_unlock(); > > - if (!is_subset && !capable(CAP_SYS_NICE)) > - return -EPERM; > - return 0; > + return ret; > } > > /**