From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Stephen Smalley <sds@tycho.nsa.gov>
Cc: "Xing, Cedric" <cedric.xing@intel.com>,
"linux-security-module@vger.kernel.org"
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"Roberts, William C" <william.c.roberts@intel.com>,
"Tricca, Philip B" <philip.b.tricca@intel.com>
Subject: Re: [RFC PATCH v1 2/3] LSM/x86/sgx: Implement SGX specific hooks in SELinux
Date: Thu, 13 Jun 2019 12:48:33 -0700 [thread overview]
Message-ID: <20190613194833.GB18385@linux.intel.com> (raw)
In-Reply-To: <b7f3decf-b1d2-01b1-6294-ccf9ba2d5df4@tycho.nsa.gov>
On Thu, Jun 13, 2019 at 02:00:29PM -0400, Stephen Smalley wrote:
> On 6/11/19 6:55 PM, Xing, Cedric wrote:
> >You are right that there are SGX specific stuff. More precisely, SGX
> >enclaves don't have access to anything except memory, so there are only 3
> >questions that need to be answered for each enclave page: 1) whether X is
> >allowed; 2) whether W->X is allowed and 3 whether WX is allowed. This
> >proposal tries to cache the answers to those questions upon creation of each
> >enclave page, meaning it involves a) figuring out the answers and b)
> >"remember" them for every page. #b is generic, mostly captured in
> >intel_sgx.c, and could be shared among all LSM modules; while #a is SELinux
> >specific. I could move intel_sgx.c up one level in the directory hierarchy
> >if that's what you'd suggest.
> >
> >By "SGX", did you mean the SGX subsystem being upstreamed? It doesn’t track
> >that state. In practice, there's no way for SGX to track it because there's
> >no vm_ops->may_mprotect() callback. It doesn't follow the philosophy of
> >Linux either, as mprotect() doesn't track it for regular memory. And it
> >doesn't have a use without LSM, so I believe it makes more sense to track it
> >inside LSM.
>
> Yes, the SGX driver/subsystem. I had the impression from Sean that it does
> track this kind of per-page state already in some manner, but possibly he
> means it does under a given proposal and not in the current driver.
Yeah, under a given proposal. SGX has per-page tracking, adding new flags
is fairly easy. Philosophical objections aside, adding .may_mprotect() is
trivial.
> Even the #b remembering might end up being SELinux-specific if we also have
> to remember the original inputs used to compute the answer so that we can
> audit that information when access is denied later upon mprotect(). At the
> least we'd need it to save some opaque data and pass it to a callback into
> SELinux to perform that auditing.
next prev parent reply other threads:[~2019-06-13 19:48 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 2:11 [RFC PATCH v2 0/5] security: x86/sgx: SGX vs. LSM Sean Christopherson
2019-06-06 2:11 ` [RFC PATCH v2 1/5] mm: Introduce vm_ops->may_mprotect() Sean Christopherson
2019-06-10 15:06 ` Jarkko Sakkinen
2019-06-10 15:55 ` Sean Christopherson
2019-06-10 17:47 ` Xing, Cedric
2019-06-10 19:49 ` Sean Christopherson
2019-06-10 22:06 ` Xing, Cedric
2019-06-06 2:11 ` [RFC PATCH v2 2/5] x86/sgx: Require userspace to define enclave pages' protection bits Sean Christopherson
2019-06-10 15:27 ` Jarkko Sakkinen
2019-06-10 16:15 ` Sean Christopherson
2019-06-10 17:45 ` Jarkko Sakkinen
2019-06-10 18:17 ` Sean Christopherson
2019-06-12 19:26 ` Jarkko Sakkinen
2019-06-10 18:29 ` Xing, Cedric
2019-06-10 19:15 ` Andy Lutomirski
2019-06-10 22:28 ` Xing, Cedric
2019-06-12 0:09 ` Andy Lutomirski
2019-06-12 14:34 ` Sean Christopherson
2019-06-12 18:20 ` Xing, Cedric
2019-06-06 2:11 ` [RFC PATCH v2 3/5] x86/sgx: Enforce noexec filesystem restriction for enclaves Sean Christopherson
2019-06-10 16:00 ` Jarkko Sakkinen
2019-06-10 16:44 ` Andy Lutomirski
2019-06-11 17:21 ` Stephen Smalley
2019-06-06 2:11 ` [RFC PATCH v2 4/5] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX Sean Christopherson
2019-06-07 19:58 ` Stephen Smalley
2019-06-10 16:21 ` Sean Christopherson
2019-06-10 16:05 ` Jarkko Sakkinen
2019-06-06 2:11 ` [RFC PATCH v2 5/5] security/selinux: Add enclave_load() implementation Sean Christopherson
2019-06-07 21:16 ` Stephen Smalley
2019-06-10 16:46 ` Sean Christopherson
2019-06-17 16:38 ` Jarkko Sakkinen
2019-06-10 7:03 ` [RFC PATCH v1 0/3] security/x86/sgx: SGX specific LSM hooks Cedric Xing
2019-06-10 7:03 ` [RFC PATCH v1 1/3] LSM/x86/sgx: Add " Cedric Xing
2019-06-10 7:03 ` [RFC PATCH v1 2/3] LSM/x86/sgx: Implement SGX specific hooks in SELinux Cedric Xing
2019-06-11 13:40 ` Stephen Smalley
2019-06-11 22:02 ` Sean Christopherson
2019-06-12 9:32 ` Dr. Greg
2019-06-12 14:25 ` Sean Christopherson
2019-06-13 7:25 ` Dr. Greg
2019-06-12 19:30 ` Andy Lutomirski
2019-06-12 22:02 ` Sean Christopherson
2019-06-13 0:10 ` Xing, Cedric
2019-06-13 1:02 ` Xing, Cedric
2019-06-13 17:02 ` Stephen Smalley
2019-06-13 23:03 ` Xing, Cedric
2019-06-13 23:17 ` Sean Christopherson
2019-06-14 0:31 ` Xing, Cedric
2019-06-14 0:46 ` Sean Christopherson
2019-06-14 15:38 ` Sean Christopherson
2019-06-16 22:14 ` Andy Lutomirski
2019-06-17 16:49 ` Sean Christopherson
2019-06-17 17:08 ` Andy Lutomirski
2019-06-18 15:40 ` Dr. Greg
2019-06-14 17:16 ` Xing, Cedric
2019-06-14 17:45 ` Sean Christopherson
2019-06-14 17:53 ` Sean Christopherson
2019-06-14 20:01 ` Sean Christopherson
2019-06-16 22:16 ` Andy Lutomirski
2019-06-14 23:19 ` Dr. Greg
2019-06-11 22:55 ` Xing, Cedric
2019-06-13 18:00 ` Stephen Smalley
2019-06-13 19:48 ` Sean Christopherson [this message]
2019-06-13 21:09 ` Xing, Cedric
2019-06-13 21:02 ` Xing, Cedric
2019-06-14 0:37 ` Sean Christopherson
2019-06-10 7:03 ` [RFC PATCH v1 3/3] LSM/x86/sgx: Call new LSM hooks from SGX subsystem Cedric Xing
2019-06-10 17:36 ` [RFC PATCH v1 0/3] security/x86/sgx: SGX specific LSM hooks Jarkko Sakkinen
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