From: James Morris <jmorris@namei.org>
To: Casey Schaufler <casey@schaufler-ca.com>
Cc: Casey Schaufler <casey.schaufler@intel.com>,
kristen@linux.intel.com, kernel-hardening@lists.openwall.com,
deneen.t.dock@intel.com, linux-kernel@vger.kernel.org,
dave.hansen@intel.com, linux-security-module@vger.kernel.org,
selinux@tycho.nsa.gov, arjan@linux.intel.com
Subject: Re: [PATCH v5 5/5] sidechannel: Linux Security Module for sidechannel
Date: Fri, 28 Sep 2018 08:47:13 +1000 (AEST) [thread overview]
Message-ID: <alpine.LRH.2.21.1809280846280.8410@namei.org> (raw)
In-Reply-To: <025d4742-5947-545e-f603-502a0c5ee03f@schaufler-ca.com>
On Thu, 27 Sep 2018, Casey Schaufler wrote:
> On 9/27/2018 2:45 PM, James Morris wrote:
> > On Wed, 26 Sep 2018, Casey Schaufler wrote:
> >
> >> + /*
> >> + * Namespace checks. Considered safe if:
> >> + * cgroup namespace is the same
> >> + * User namespace is the same
> >> + * PID namespace is the same
> >> + */
> >> + if (current->nsproxy)
> >> + ccgn = current->nsproxy->cgroup_ns;
> >> + if (p->nsproxy)
> >> + pcgn = p->nsproxy->cgroup_ns;
> >> + if (ccgn != pcgn)
> >> + return -EACCES;
> >> + if (current->cred->user_ns != p->cred->user_ns)
> >> + return -EACCES;
> >> + if (task_active_pid_ns(current) != task_active_pid_ns(p))
> >> + return -EACCES;
> >> + return 0;
> > I really don't like the idea of hard-coding namespace security semantics
> > in an LSM. Also, I'm not sure if these semantics make any sense.
>
> Checks on namespaces where explicitly requested.
By whom and what is the rationale?
--
James Morris
<jmorris@namei.org>
next prev parent reply other threads:[~2018-09-27 22:48 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-26 20:34 [PATCH v5 0/5] LSM: Support ptrace sidechannel access checks Casey Schaufler
2018-09-26 20:34 ` [PATCH v5 1/5] AppArmor: Prepare for PTRACE_MODE_SCHED Casey Schaufler
2018-09-26 21:16 ` Jann Horn
2018-09-26 21:18 ` Jann Horn
2018-09-26 22:47 ` Schaufler, Casey
2018-09-26 20:34 ` [PATCH v5 2/5] Smack: " Casey Schaufler
2018-09-26 21:30 ` Jann Horn
2018-09-26 22:53 ` Schaufler, Casey
2018-09-26 22:58 ` Jann Horn
2018-10-04 7:47 ` Jiri Kosina
2018-10-04 11:36 ` Jann Horn
2018-10-16 11:44 ` Jiri Kosina
2018-09-26 20:34 ` [PATCH v5 3/5] SELinux: " Casey Schaufler
2018-09-27 15:50 ` Stephen Smalley
2018-09-27 16:23 ` Schaufler, Casey
2018-09-26 20:34 ` [PATCH v5 4/5] Capability: Complete PTRACE_MODE_SCHED Casey Schaufler
2018-09-26 21:26 ` Jann Horn
2018-09-26 22:24 ` Schaufler, Casey
2018-09-26 20:34 ` [PATCH v5 5/5] sidechannel: Linux Security Module for sidechannel Casey Schaufler
2018-09-27 21:45 ` James Morris
2018-09-27 22:39 ` Casey Schaufler
2018-09-27 22:47 ` James Morris [this message]
2018-09-27 23:19 ` Schaufler, Casey
2018-09-27 23:43 ` James Morris
2018-09-27 23:47 ` Jann Horn
2018-09-28 16:33 ` James Morris
2018-09-28 17:40 ` Schaufler, Casey
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