Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752528AbXA2RoK (ORCPT ); Mon, 29 Jan 2007 12:44:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752522AbXA2RoJ (ORCPT ); Mon, 29 Jan 2007 12:44:09 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:40893 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524AbXA2RoF (ORCPT ); Mon, 29 Jan 2007 12:44:05 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Stephen Smalley Cc: Andrew Morton , Ingo Molnar , tglx@linutronix.de, linux-kernel@vger.kernel.org, selinux@tycho.nsa.gov, jmorris@namei.org Subject: Re: [PATCH] sysctl selinux: Don't look at table->de References: <200701280106.l0S16CG3019873@shell0.pdx.osdl.net> <20070127172410.2b041952.akpm@osdl.org> <1169972718.17469.164.camel@localhost.localdomain> <20070128003549.2ca38dc8.akpm@osdl.org> <20070128093358.GA2071@elte.hu> <20070128095712.GA6485@elte.hu> <20070128100627.GA8416@elte.hu> <20070128104548.a835d859.akpm@osdl.org> <1170075866.8720.15.camel@moss-spartans.epoch.ncsc.mil> Date: Mon, 29 Jan 2007 10:43:07 -0700 In-Reply-To: <1170075866.8720.15.camel@moss-spartans.epoch.ncsc.mil> (Stephen Smalley's message of "Mon, 29 Jan 2007 08:04:26 -0500") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3032 Lines: 69 Stephen Smalley writes: > On Sun, 2007-01-28 at 12:21 -0700, Eric W. Biederman wrote: >> With the sysctl cleanups sysctl is not really a part of proc >> it just shows up there, and any path based approach will not >> adequately describe the data as sysctl is essentially a >> union mount underneath the covers. As designed this mechanism >> is viewer dependent so trying to be path based gets even worse. >> >> However the permissions in sys_sysctl are currently immutable >> and going through proc does not change the permission checks >> when accessing sysctl. So we might as well stick with the well >> defined sysctl sid, as that is what selinux uses when proc is >> not compiled in. >> >> I.e. I see no hope for salvaging the selinux_proc_get_sid call >> in selinux_sysctl so I'm removing it. >> >> Signed-off-by: Eric W. Biederman >> --- >> security/selinux/hooks.c | 8 ++------ >> 1 files changed, 2 insertions(+), 6 deletions(-) >> >> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c >> index 7b38372..3a36057 100644 >> --- a/security/selinux/hooks.c >> +++ b/security/selinux/hooks.c >> @@ -1438,12 +1438,8 @@ static int selinux_sysctl(ctl_table *table, int op) >> >> tsec = current->security; >> >> - rc = selinux_proc_get_sid(table->de, (op == 001) ? >> - SECCLASS_DIR : SECCLASS_FILE, &tsid); >> - if (rc) { >> - /* Default to the well-defined sysctl SID. */ >> - tsid = SECINITSID_SYSCTL; >> - } >> + /* Use the well-defined sysctl SID. */ >> + tsid = SECINITSID_SYSCTL; >> >> /* The op values are "defined" in sysctl.c, thereby creating >> * a bad coupling between this module and sysctl.c */ > > NAK. Mapping all sysctls to a single security label prevents any kind > of fine-grained security on sysctls, and current policies already make > use of the current distinctions to limit access to particular sets of > sysctls to particular processes. As is, I'd expect breakage of current > systems running SELinux from this patch, because (confined) processes > that formerly only required access to specific sysctl labels will > suddenly run into denials on the generic fallback label. Reasonable. There is the issue that your code already had this code path for when /proc was compiled out. > If the ctl_table supplied more information about the functional purpose > and the security sensitivity of the sysctl, then we could leverage that > information instead, as long as we can at least derive the current > labelings from that information for compatibility. What do information do you need to do need? Do you need extra fields in sysctl? I am more than willing to help but I am not familiar enough with selinux to do a reasonable job on my own. Eric - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/