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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	linux-sgx@vger.kernel.org, akpm@linux-foundation.org,
	dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com,
	haitao.huang@intel.com, andriy.shevchenko@linux.intel.com,
	tglx@linutronix.de, kai.svahn@intel.com, josh@joshtriplett.org,
	luto@kernel.org, kai.huang@intel.com, rientjes@google.com,
	cedric.xing@intel.com, puiterwijk@redhat.com,
	Jethro Beekman <jethro@fortanix.com>
Subject: Re: [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures
Date: Fri, 22 May 2020 09:13:26 -0700
Message-ID: <20200522161326.GC25128@linux.intel.com> (raw)
In-Reply-To: <20200522155405.GA8377@linux.intel.com>

On Fri, May 22, 2020 at 06:54:05PM +0300, Jarkko Sakkinen wrote:
> On Wed, May 20, 2020 at 08:47:45PM +0200, Borislav Petkov wrote:
> > On Fri, May 15, 2020 at 03:43:54AM +0300, Jarkko Sakkinen wrote:
> > > +/**
> > > + * struct sgx_sigstruct_header -  defines author of the enclave
> > > + * @header1:		constant byte string
> > > + * @vendor:		must be either 0x0000 or 0x8086
> > 
> > Out of pure curiosity: what is that about?
> > 
> > Nothing in the patchset enforces this, so hw does? If so, why?
> > 
> > Are those vendor IDs going to be assigned by someone or what's up?
> > 
> > Thx.
> 
> In SGX1 world 0x8086 was used to mark architectural enclaves and 0x0000
> user run enclaves. In SGX2 world they are irrelevant.

That's not accurate, the vendor is irrelevant in all SGX eras, e.g. enclaves
signed by someone other than Intel can use 0x8086 on SGX1 hardware and even
pre-LC hardware.  0x8086 is/was used as an _informal_ "this is an
Intel-signed enclave", but in no way was it mandatory or reliable.

> In order to retain compatiblity I'd add an explicit check to:
> 
> 1. Allow vendor ID of 0x0000 or 0x8086.
> 2. Reject other vendor ID's (-EINVAL).

Unless we also check the reserved fields in sigstruct, I don't see the
point.  Even then, I don't understand what the kernel gains from enforcing
anything with respect to sigstruct.  Enforcing the SECS makes sense as we
don't want to allow userspace to enable some unknown future feature.  But
sigstruct is purely for verification, we (Intel) have far bigger problems
if Intel is enabling new behavior via sigstruct.

That being said, I'm not dead set against sanity checking sigstruct, I just
think it'd be a waste of cycles.

  reply index

Thread overview: 74+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-15  0:43 [PATCH v30 00/20] Intel SGX foundations Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 01/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-05-20 12:16   ` Borislav Petkov
2020-05-20 14:00     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 02/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2020-05-20 12:23   ` Borislav Petkov
2020-05-20 14:04     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 03/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 04/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-05-20 18:47   ` Borislav Petkov
2020-05-20 21:04     ` Sean Christopherson
2020-05-22 15:54     ` Jarkko Sakkinen
2020-05-22 16:13       ` Sean Christopherson [this message]
2020-05-22 19:50         ` Jarkko Sakkinen
2020-05-25  8:20           ` Borislav Petkov
2020-05-27 19:43             ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 05/20] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 06/20] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 07/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2020-05-25  9:23   ` Borislav Petkov
2020-05-27  3:56     ` Sean Christopherson
2020-05-27 20:35       ` Borislav Petkov
2020-05-28  7:36         ` Jarkko Sakkinen
2020-05-28  5:25       ` Jarkko Sakkinen
2020-05-28  5:35         ` Jarkko Sakkinen
2020-05-28  6:14           ` Jarkko Sakkinen
2020-05-28  6:16             ` Jarkko Sakkinen
2020-05-28  5:13     ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2020-05-26 12:52   ` Borislav Petkov
2020-05-27  4:21     ` Sean Christopherson
2020-05-27 20:46       ` Borislav Petkov
2020-05-28  0:52         ` Sean Christopherson
2020-05-28  6:51           ` Jarkko Sakkinen
2020-05-28  1:23         ` Jarkko Sakkinen
2020-05-28  1:36           ` Sean Christopherson
2020-05-28  6:52             ` Jarkko Sakkinen
2020-05-28 17:16               ` Borislav Petkov
2020-05-28 17:19                 ` Sean Christopherson
2020-05-28 17:27                   ` Borislav Petkov
2020-05-28 17:34                     ` Sean Christopherson
2020-05-28 19:07                 ` Jarkko Sakkinen
2020-05-28 19:59                   ` Sean Christopherson
2020-05-29  3:28                     ` Jarkko Sakkinen
2020-05-29  3:37                       ` Sean Christopherson
2020-05-29  5:07                         ` Jarkko Sakkinen
2020-05-29  8:12                         ` Jarkko Sakkinen
2020-05-29  8:13                           ` Jarkko Sakkinen
2020-05-29  3:38                       ` Jarkko Sakkinen
2020-05-15  0:43 ` [PATCH v30 09/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-05-29 12:10   ` Borislav Petkov
2020-05-29 18:18     ` Jarkko Sakkinen
2020-05-29 18:28   ` Dave Hansen
2020-05-15  0:44 ` [PATCH v30 10/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-05-21 19:12   ` Sean Christopherson
2020-05-22 19:26     ` Jarkko Sakkinen
2020-05-22 19:39     ` Jarkko Sakkinen
2020-05-22  3:33   ` Sean Christopherson
2020-05-15  0:44 ` [PATCH v30 11/20] x86/sgx: Add provisioning Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 12/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-05-22  6:58   ` Sean Christopherson
2020-05-22 19:57     ` Jarkko Sakkinen
2020-05-22 21:52       ` Sean Christopherson
2020-05-22  7:15   ` Sean Christopherson
2020-05-22 19:47     ` Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 13/20] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 14/20] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 15/20] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 16/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 17/20] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 18/20] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 19/20] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-05-15  0:44 ` [PATCH v30 20/20] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-05-16  8:57 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen

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