From: Sebastien Buisson <sbuisson.ddn@gmail.com>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: Paul Moore <pmoore@redhat.com>,
selinux@tycho.nsa.gov, william.c.roberts@intel.com,
linux-kernel@vger.kernel.org,
linux-security-module@vger.kernel.org,
Sebastien Buisson <sbuisson@ddn.com>,
james.l.morris@oracle.com
Subject: Re: [PATCH] selinux: add selinux_is_enforced() function
Date: Wed, 12 Apr 2017 17:11:43 +0200 [thread overview]
Message-ID: <CAPkE-bWQLfSq0+J0uoMRKAPbSdO0giuGZzfRXA7VXL+xo3fNgg@mail.gmail.com> (raw)
In-Reply-To: <1492007701.3881.10.camel@tycho.nsa.gov>
2017-04-12 16:35 GMT+02:00 Stephen Smalley <sds@tycho.nsa.gov>:
> How are you using this SELinux information in the kernel and/or in
> userspace? What's the purpose of it? What are you comparing it
> against? Why do you care if it changes?
Enforcement status and policy version are compared to their previously
stored value. If they differ, then it means we need to call a userland
helper from Lustre client kernelspace to read the currently loaded
policy (reading it will let us know if the Lustre client node is
conforming to the Lustre-wide security policy).
As calling the userland helper is costly, we do it only when it is
necessary by retrieving some SELinux key information directly from
kernelspace.
> Note btw that the notion of a policy name/type and the policy file path
> is purely a userspace construct and shouldn't be embedded in your
> kernel code. Android for example doesn't follow that convention at
> all; their SELinux policy file is simply /sepolicy. On modern kernels,
> you can always read the currently loaded policy from the kernel itself
> via /sys/fs/selinux/policy (formerly just /selinux/policy).
As I understand it, a userspace program can directly read the policy
info exposed by the kernel by reading this file. But how about reading
it from kernelspace?
next prev parent reply other threads:[~2017-04-12 15:12 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-12 9:06 [PATCH] selinux: add selinux_is_enforced() function Sebastien Buisson
2017-04-12 11:55 ` Paul Moore
2017-04-12 13:30 ` Sebastien Buisson
2017-04-12 13:58 ` Stephen Smalley
2017-04-12 15:19 ` Sebastien Buisson
2017-04-12 16:33 ` Stephen Smalley
2017-04-13 0:12 ` Casey Schaufler
2017-04-12 13:30 ` Sebastien Buisson
2017-04-12 14:35 ` Stephen Smalley
2017-04-12 15:11 ` Sebastien Buisson [this message]
2017-04-12 16:24 ` Stephen Smalley
2017-04-12 17:07 ` Sebastien Buisson
2017-04-12 17:24 ` Stephen Smalley
2017-04-12 12:13 ` Stephen Smalley
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