From: Andy Lutomirski <luto@kernel.org>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "Dr. Greg" <greg@enjellic.com>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
linux-sgx@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Dave Hansen <dave.hansen@intel.com>,
Neil Horman <nhorman@redhat.com>,
npmccallum@redhat.com, "Huang, Haitao" <haitao.huang@intel.com>,
Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"Svahn, Kai" <kai.svahn@intel.com>,
Borislav Petkov <bp@alien8.de>,
Josh Triplett <josh@joshtriplett.org>,
Andrew Lutomirski <luto@kernel.org>,
"Huang, Kai" <kai.huang@intel.com>,
David Rientjes <rientjes@google.com>,
"Xing, Cedric" <cedric.xing@intel.com>,
puiterwijk@redhat.com
Subject: Re: [PATCH v29 00/20] Intel SGX foundations
Date: Thu, 7 May 2020 17:40:11 -0700 [thread overview]
Message-ID: <CALCETrX9w3anusPhNWkv-hs554N6MF9GfChazrG+Br16oFfCaw@mail.gmail.com> (raw)
In-Reply-To: <20200429153004.GD15992@linux.intel.com>
On Wed, Apr 29, 2020 at 8:30 AM Sean Christopherson
<sean.j.christopherson@intel.com> wrote:
>
> On Sun, Apr 26, 2020 at 11:57:53AM -0500, Dr. Greg wrote:
> > In closing, it is important to note that the proposed SGX driver is
> > not available as a module. This effectively excludes any alternative
> > implementations of the driver without replacement of the kernel at
> > large.
>
> No it doesn't. The SGX subsytem won't allocate EPC pages unless userspace
> creates an enclave, i.e. preventing unprivileged userspace from accessing
> /dev/sgx/enclave will allow loading an alternative out-of-tree SGX module.
> Yes, SGX sanitizes the EPC on boot, but that's arguably a good thing for
> out-of-tree modules.
>
> And if you want to get crafty and squash in-kernel SGX altogether, boot
> with "clearcpuid=<SGX_LC>" and/or "clearcpuid=<SGX>" to disable in-kernel
> support entirely. SGX won't be correctly enumerated in /proc/cpuinfo
> relative to the existence of an out-of-tree module, but that seems like a
> very minor issue if you're running with a completely different SGX driver.
>
> > It also means that any platform, with SGX hardware support,
> > running a kernel with this driver, has the potential for the
> > security/privacy issues noted above.
>
> Unless I'm mistaken, /dev/sgx is root-only by default. There are far
> scarier mechanisms available to root for hosing the system.
>
> > If key based policy management is not allowed, then the driver needs
> > to be re-architected to have modular support so that alternative
> > implementations or the absence of any driver support are at least
> > tenable.
>
> As above, using an alternative implementation is teneble, albeit a bit
> kludgy.
It is worth noting that, if someone actualy does this, and a future
kernel patch breaks it, the upstream developers are unlikely to
apologize or even feel particularly bad. See, for example, the
current situation with VirtualBox.
next prev parent reply other threads:[~2020-05-08 0:40 UTC|newest]
Thread overview: 83+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-21 21:52 [PATCH v29 00/20] Intel SGX foundations Jarkko Sakkinen
2020-04-21 21:52 ` [PATCH v29 01/20] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2020-04-21 21:52 ` [PATCH v29 02/20] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2020-04-21 21:52 ` [PATCH v29 03/20] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 04/20] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 05/20] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 06/20] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 07/20] x86/cpu/intel: Detect SGX support Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 08/20] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 09/20] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 10/20] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 11/20] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2020-05-08 19:09 ` Sean Christopherson
2020-04-21 21:53 ` [PATCH v29 12/20] x86/sgx: Add provisioning Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 13/20] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 14/20] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2020-05-06 21:50 ` Sean Christopherson
2020-05-13 21:40 ` Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 15/20] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 16/20] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 17/20] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 18/20] x86/vdso: Implement a vDSO for Intel SGX enclave call Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 19/20] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2020-04-21 21:53 ` [PATCH v29 20/20] docs: x86/sgx: Document SGX micro architecture and kernel internals Jarkko Sakkinen
2020-04-22 16:48 ` [PATCH v29 00/20] Intel SGX foundations Connor Kuehl
2020-04-29 5:22 ` Jarkko Sakkinen
2020-04-26 16:57 ` Dr. Greg
2020-04-29 5:23 ` Jarkko Sakkinen
2020-04-29 15:14 ` Sean Christopherson
2020-04-30 3:59 ` Jarkko Sakkinen
2020-05-02 23:05 ` Dr. Greg
2020-05-03 0:48 ` Andy Lutomirski
2020-05-04 9:34 ` Dr. Greg
2020-04-29 15:30 ` Sean Christopherson
2020-05-08 0:40 ` Andy Lutomirski [this message]
2020-05-07 0:41 ` Thomas Gleixner
2020-05-08 19:02 ` Dr. Greg
2020-05-08 19:56 ` Sean Christopherson
2020-05-14 9:16 ` Dr. Greg
2020-05-14 16:15 ` Sean Christopherson
2020-05-14 16:20 ` Borislav Petkov
2020-05-14 19:29 ` Thomas Gleixner
2020-05-15 9:28 ` Jarkko Sakkinen
2020-05-15 9:42 ` Borislav Petkov
2020-05-15 16:24 ` Jarkko Sakkinen
2020-05-15 0:09 ` Jarkko Sakkinen
2020-05-15 19:54 ` Nathaniel McCallum
2020-05-16 9:58 ` Jarkko Sakkinen
2020-05-24 21:27 ` Pavel Machek
2020-05-26 8:16 ` David Laight
2020-04-26 17:03 ` Dr. Greg
2020-04-29 15:27 ` Jethro Beekman
2020-04-30 3:46 ` Jarkko Sakkinen
2020-04-30 7:19 ` Jethro Beekman
2020-04-30 8:23 ` Jarkko Sakkinen
2020-04-30 14:12 ` Jethro Beekman
2020-05-06 12:16 ` Jarkko Sakkinen
2020-05-06 16:39 ` Jordan Hand
2020-05-07 18:06 ` Dr. Greg
2020-05-08 16:16 ` Jordan Hand
2020-05-13 23:09 ` Jarkko Sakkinen
2020-05-06 21:42 ` Nathaniel McCallum
2020-05-06 22:14 ` Sean Christopherson
2020-05-07 5:02 ` Haitao Huang
2020-05-07 16:49 ` Nathaniel McCallum
2020-05-07 19:34 ` Sean Christopherson
2020-05-07 22:35 ` Haitao Huang
2020-05-08 0:25 ` Sean Christopherson
2020-05-28 11:15 ` Jarkko Sakkinen
2020-05-28 11:19 ` Jarkko Sakkinen
2020-05-07 22:31 ` Haitao Huang
2020-05-13 22:14 ` Jarkko Sakkinen
2020-05-13 22:18 ` Jarkko Sakkinen
2020-05-14 6:31 ` Jethro Beekman
2020-05-14 19:30 ` Thomas Gleixner
2020-05-15 0:22 ` Jarkko Sakkinen
2020-05-08 19:08 ` Sean Christopherson
2020-05-14 19:05 ` Seth Moore
2020-05-15 0:23 ` Jarkko Sakkinen
2020-05-12 11:55 ` Hui, Chunyang
2020-05-12 16:51 ` Dr. Greg
2020-05-14 10:49 ` Jarkko Sakkinen
2020-05-16 8:53 ` [PATCH] x86/cpu/intel: Add nosgx kernel parameter Jarkko Sakkinen
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