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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	x86@kernel.org, linux-sgx@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	Jethro Beekman <jethro@fortanix.com>,
	Andy Lutomirski <luto@kernel.org>,
	akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com,
	asapek@google.com, cedric.xing@intel.com,
	chenalexchen@google.com, conradparker@google.com,
	cyhanish@google.com, dave.hansen@intel.com,
	haitao.huang@intel.com, josh@joshtriplett.org,
	kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com,
	ludloff@google.com, nhorman@redhat.com, npmccallum@redhat.com,
	puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de,
	yaozhangx@google.com
Subject: Re: [PATCH v33 12/21] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation
Date: Tue, 30 Jun 2020 07:20:28 -0700	[thread overview]
Message-ID: <20200630142027.GA7733@linux.intel.com> (raw)
In-Reply-To: <20200630084956.GB1093@zn.tnic>

On Tue, Jun 30, 2020 at 10:49:56AM +0200, Borislav Petkov wrote:
> On Mon, Jun 29, 2020 at 03:04:00PM -0700, Sean Christopherson wrote:
> > /dev/sgx/provision is root-only by default, the expectation is that the admin
> > will configure the system to grant only specific enclaves access to the
> > PROVISION_KEY.
> 
> Uuh, I don't like "the expectation is" - the reality happens to turn
> differently, more often than not.

Would it help if I worded it as "only root should ever be able to run an
enclave with access to PROVISION_KEY"?  We obviously can't control what
admins actually do, hence my wording of it as the expected behavior.

> > In this series, access is fairly binary, i.e. there's no additional kernel
> > infrastructure to help userspace make per-enclave decisions.  There have been
> > more than a few proposals on how to extend the kernel to help provide better
> > granularity, e.g. LSM hooks, but it was generally agreed to punt that stuff
> > to post-upstreaming to keep things "simple" once we went far enough down
> > various paths to ensure we weren't painting ourselves into a corner.
> 
> So this all sounds to me like we should not upstream /dev/sgx/provision
> now but delay it until the infrastructure for that has been made more
> concrete. We can always add it then. Changing it after the fact -
> if we have to and for whatever reason - would be a lot harder for a
> user-visible interface which someone has started using already.

The userspace and attestation infrastructure is very concrete, i.e. the
need for userspace to be able to access PROVISION_KEY is there, as is the
desire to be able to restrict access to PROVISION_KEY, e.g. I believe Andy
Lutomirski originally requested the ability to restrict access.

The additional infrastructure for per-enclave decisions is somewhat
orthogonal to the PROVISION_KEY, e.g. they won't necessarily be employed
by everyone running enclaves, and environments that do have per-enclave
policies would still likely want the extra layer of restriction for
PROVISION_KEY.  I only brought the additional policy crud to call out that
we've done enough path-finding on additional restrictions to have strong
confidence that adding /dev/sgx/provision won't prevent us from adding more
fine grained control in the future.

> So I'd leave  that out from the initial patchset.

  reply	other threads:[~2020-06-30 14:20 UTC|newest]

Thread overview: 93+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-17 22:08 [PATCH v33 00/21] Intel SGX foundations Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 01/21] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-06-22 17:37   ` Borislav Petkov
2020-06-25  1:25     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 02/21] x86/cpufeatures: x86/msr: Add Intel SGX Launch Control " Jarkko Sakkinen
2020-06-24 13:04   ` Borislav Petkov
2020-06-24 14:34     ` Sean Christopherson
2020-06-25  1:28       ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 03/21] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-06-25  8:59   ` Borislav Petkov
2020-06-25 15:34     ` Sean Christopherson
2020-06-25 16:49       ` Borislav Petkov
2020-06-25 20:52     ` Jarkko Sakkinen
2020-06-25 21:11       ` Borislav Petkov
2020-06-26 13:34         ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 04/21] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 05/21] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 06/21] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 07/21] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 08/21] x86/sgx: Initialize metadata for Enclave Page Cache (EPC) sections Jarkko Sakkinen
2020-06-25 10:14   ` Borislav Petkov
2020-06-25 20:11     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 09/21] x86/sgx: Add __sgx_alloc_epc_page() and sgx_free_epc_page() Jarkko Sakkinen
2020-06-25 17:06   ` Borislav Petkov
2020-06-25 20:55     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 10/21] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-06-25 17:14   ` Borislav Petkov
2020-06-25 17:30     ` Matthew Wilcox
2020-06-25 18:06       ` Sean Christopherson
2020-06-25 22:40         ` Jarkko Sakkinen
2020-06-25 22:26     ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 11/21] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-06-25 17:23   ` Borislav Petkov
2020-06-25 18:34     ` Sean Christopherson
2020-06-25 18:45       ` Borislav Petkov
2020-06-26 14:19       ` Jarkko Sakkinen
2020-06-25 20:21     ` Jarkko Sakkinen
2020-06-25 20:25       ` Borislav Petkov
2020-06-26 13:40         ` Jarkko Sakkinen
2020-06-25 18:53   ` Borislav Petkov
2020-06-26 14:17     ` Jarkko Sakkinen
2020-06-26  9:14   ` Borislav Petkov
2020-06-26 14:16     ` Sean Christopherson
2020-06-26 14:20       ` Borislav Petkov
2020-07-03 23:04         ` Jarkko Sakkinen
2020-07-03  3:09     ` Jarkko Sakkinen
2020-06-26 15:34   ` Borislav Petkov
2020-07-04  0:13     ` Jarkko Sakkinen
2020-10-26 21:26     ` Dave Hansen
2020-10-27  1:52       ` Jarkko Sakkinen
2020-10-27 10:05       ` Borislav Petkov
2020-10-27 15:20         ` Dave Hansen
2020-10-27 15:37           ` Borislav Petkov
2020-06-27 17:43   ` Borislav Petkov
2020-06-29 15:27     ` Sean Christopherson
2020-06-29 15:37       ` Borislav Petkov
2020-07-04  1:43       ` Jarkko Sakkinen
2020-07-07  1:38         ` Sean Christopherson
2020-07-07  3:29           ` Jarkko Sakkinen
2020-07-04  1:42     ` Jarkko Sakkinen
2020-07-02  3:59   ` Sean Christopherson
2020-07-04  3:31     ` Jarkko Sakkinen
2020-09-02  3:06       ` Haitao Huang
2020-09-02 16:10         ` Sean Christopherson
2020-09-02 18:40           ` Haitao Huang
2020-09-04 12:01         ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 12/21] x86/sgx: Allow a limited use of ATTRIBUTE.PROVISIONKEY for attestation Jarkko Sakkinen
2020-06-29 16:02   ` Borislav Petkov
2020-06-29 22:04     ` Sean Christopherson
2020-06-30  8:49       ` Borislav Petkov
2020-06-30 14:20         ` Sean Christopherson [this message]
2020-06-30 17:13           ` Andy Lutomirski
2020-07-02 20:47         ` Dr. Greg
2020-07-03  2:43         ` Jarkko Sakkinen
2020-07-03  2:38       ` Jarkko Sakkinen
2020-07-03  2:32     ` Jarkko Sakkinen
2020-07-03  2:55       ` Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 13/21] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 14/21] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 15/21] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-06-29 17:10   ` Borislav Petkov
2020-06-30  6:00     ` Sean Christopherson
2020-06-30  8:41       ` Borislav Petkov
2020-06-30 14:55         ` Sean Christopherson
2020-06-30 16:48         ` Andy Lutomirski
2020-06-30 17:23           ` Sean Christopherson
2020-07-02 12:52           ` Thomas Gleixner
2020-06-17 22:08 ` [PATCH v33 16/21] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 17/21] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 18/21] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 19/21] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 20/21] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-06-17 22:08 ` [PATCH v33 21/21] x86/sgx: Update MAINTAINERS Jarkko Sakkinen

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