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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: linux-sgx@vger.kernel.org, linux-security-module@vger.kernel.org,
	selinux@vger.kernel.org,
	Bill Roberts <william.c.roberts@intel.com>,
	Casey Schaufler <casey.schaufler@intel.com>,
	James Morris <jmorris@namei.org>,
	Dave Hansen <dave.hansen@intel.com>,
	Cedric Xing <cedric.xing@intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Jethro Beekman <jethro@fortanix.com>,
	"Dr . Greg Wettstein" <greg@enjellic.com>,
	Stephen Smalley <sds@tycho.nsa.gov>
Subject: Re: [RFC PATCH v4 06/12] mm: Introduce vm_ops->may_mprotect()
Date: Fri, 21 Jun 2019 04:35:20 +0300
Message-ID: <20190621013520.GK20474@linux.intel.com> (raw)
In-Reply-To: <20190619222401.14942-7-sean.j.christopherson@intel.com>

On Wed, Jun 19, 2019 at 03:23:55PM -0700, Sean Christopherson wrote:
> SGX will use ->may_mprotect() to invoke an SGX variant of the existing
> file_mprotect() and mmap_file() LSM hooks.
> 
> The name may_mprotect() is intended to reflect the hook's purpose as a
> way to restrict mprotect() as opposed to a wholesale replacement.
> 
> Due to the nature of SGX and its Enclave Page Cache (EPC), all enclave
> VMAs are backed by a single file, i.e. /dev/sgx/enclave, that must be
> MAP_SHARED.  Furthermore, all enclaves need read, write and execute
> VMAs.  As a result, applying W^X restrictions on /dev/sgx/enclave using
> existing LSM hooks is for all intents and purposes impossible, e.g.
> denying either W or X would deny access to *any* enclave.
> 
> By hooking mprotect(), SGX can invoke an SGX specific LSM hook, which in
> turn allows LSMs to enforce W^X policies.
> 
> Alternatively, SGX could provide a helper to identify enclaves given a
> vma or file.  LSMs could then check if a mapping is for enclave and take
> action according.
> 
> A second alternative would be to have SGX implement its own LSM hooks
> for file_mprotect() and mmap_file(), using them to "forward" the call to
> the SGX specific hook.
> 
> The major con to both alternatives is that they provide zero flexibility
> for the SGX specific LSM hook.  The "is_sgx_enclave()" helper doesn't
> allow SGX can't supply any additional information whatsoever, and the
> mmap_file() hook is called before the final address is known, e.g. SGX
> can't provide any information about the specific enclave being mapped.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>

Absolutely nothing to say about this one. We can take it as part of the
main patch set as it is. Not going to apply it though before the things
have been sorted out.

/Jarkko

  reply index

Thread overview: 156+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-19 22:23 [RFC PATCH v4 00/12] security: x86/sgx: SGX vs. LSM Sean Christopherson
2019-06-19 22:23 ` [RFC PATCH v4 01/12] x86/sgx: Use mmu_notifier.release() instead of per-vma refcounting Sean Christopherson
2019-06-20 21:03   ` Jarkko Sakkinen
2019-07-08 14:57     ` Sean Christopherson
2019-07-09 16:18       ` Jarkko Sakkinen
2019-06-19 22:23 ` [RFC PATCH v4 02/12] x86/sgx: Do not naturally align MAP_FIXED address Sean Christopherson
2019-06-20 21:09   ` Jarkko Sakkinen
2019-06-20 22:09     ` Jarkko Sakkinen
2019-06-19 22:23 ` [RFC PATCH v4 03/12] selftests: x86/sgx: Mark the enclave loader as not needing an exec stack Sean Christopherson
2019-06-20 21:17   ` Jarkko Sakkinen
2019-06-19 22:23 ` [RFC PATCH v4 04/12] x86/sgx: Require userspace to define enclave pages' protection bits Sean Christopherson
2019-06-21  1:07   ` Jarkko Sakkinen
2019-06-21  1:16     ` Jarkko Sakkinen
2019-06-21 16:42   ` Xing, Cedric
2019-07-08 16:34     ` Sean Christopherson
2019-07-08 17:29       ` Xing, Cedric
2019-07-01 18:00   ` Andy Lutomirski
2019-07-01 19:22     ` Xing, Cedric
2019-06-19 22:23 ` [RFC PATCH v4 05/12] x86/sgx: Enforce noexec filesystem restriction for enclaves Sean Christopherson
2019-06-21  1:26   ` Jarkko Sakkinen
2019-07-07 19:03     ` Sean Christopherson
2019-06-19 22:23 ` [RFC PATCH v4 06/12] mm: Introduce vm_ops->may_mprotect() Sean Christopherson
2019-06-21  1:35   ` Jarkko Sakkinen [this message]
2019-06-19 22:23 ` [RFC PATCH v4 07/12] LSM: x86/sgx: Introduce ->enclave_map() hook for Intel SGX Sean Christopherson
2019-06-21  2:28   ` Jarkko Sakkinen
2019-06-21 16:54   ` Xing, Cedric
2019-06-25 20:48     ` Stephen Smalley
2019-06-27 20:29       ` Xing, Cedric
2019-07-07 18:01         ` Sean Christopherson
2019-06-19 22:23 ` [RFC PATCH v4 08/12] security/selinux: Require SGX_MAPWX to map enclave page WX Sean Christopherson
2019-06-21 17:09   ` Xing, Cedric
2019-06-25 21:05     ` Stephen Smalley
2019-06-27 20:26       ` Xing, Cedric
2019-06-25 20:19   ` Stephen Smalley
2019-06-26 12:49     ` Dr. Greg
2019-06-19 22:23 ` [RFC PATCH v4 09/12] LSM: x86/sgx: Introduce ->enclave_load() hook for Intel SGX Sean Christopherson
2019-06-21 17:05   ` Xing, Cedric
2019-06-25 21:01     ` Stephen Smalley
2019-06-25 21:49       ` Stephen Smalley
2019-06-27 19:38         ` Xing, Cedric
2019-06-19 22:23 ` [RFC PATCH v4 10/12] security/selinux: Add enclave_load() implementation Sean Christopherson
2019-06-21 21:22   ` Xing, Cedric
2019-06-25 21:09     ` Stephen Smalley
2019-06-27 20:19       ` Xing, Cedric
2019-06-28 16:16         ` Stephen Smalley
2019-06-28 21:20           ` Xing, Cedric
2019-06-29  1:15             ` Stephen Smalley
2019-07-01 18:14               ` Xing, Cedric
2019-06-29 23:41       ` Andy Lutomirski
2019-07-01 17:46         ` Xing, Cedric
2019-07-01 17:53           ` Andy Lutomirski
2019-07-01 18:54             ` Xing, Cedric
2019-07-01 19:03               ` Xing, Cedric
2019-07-01 19:32               ` Andy Lutomirski
2019-07-01 20:03                 ` Xing, Cedric
2019-07-07 18:46                   ` Sean Christopherson
2019-06-25 20:34   ` Stephen Smalley
2019-06-19 22:24 ` [RFC PATCH v4 11/12] security/apparmor: " Sean Christopherson
2019-06-19 22:24 ` [RFC PATCH v4 12/12] LSM: x86/sgx: Show line of sight to LSM support SGX2's EAUG Sean Christopherson
2019-06-21 17:18   ` Xing, Cedric
2019-07-08 14:34     ` Sean Christopherson
2019-06-21  1:32 ` [RFC PATCH v4 00/12] security: x86/sgx: SGX vs. LSM Jarkko Sakkinen
2019-06-27 18:56 ` [RFC PATCH v2 0/3] security/x86/sgx: SGX specific LSM hooks Cedric Xing
2019-07-03 23:16   ` Jarkko Sakkinen
2019-07-03 23:22     ` Jarkko Sakkinen
2019-07-03 23:23       ` Jarkko Sakkinen
2019-07-06  5:04     ` Xing, Cedric
2019-07-08 14:46       ` Jarkko Sakkinen
2019-07-07 23:41   ` [RFC PATCH v3 0/4] " Cedric Xing
2019-07-08 15:55     ` Sean Christopherson
2019-07-08 17:49       ` Xing, Cedric
2019-07-08 18:49         ` Sean Christopherson
2019-07-08 22:26           ` Xing, Cedric
2019-07-07 23:41   ` [RFC PATCH v3 1/4] x86/sgx: Add " Cedric Xing
2019-07-07 23:41   ` [RFC PATCH v3 2/4] x86/64: Call LSM hooks from SGX subsystem/module Cedric Xing
2019-07-09  1:03     ` Sean Christopherson
2019-07-07 23:41   ` [RFC PATCH v3 3/4] X86/sgx: Introduce EMA as a new LSM module Cedric Xing
2019-07-08 16:26     ` Casey Schaufler
2019-07-08 17:16       ` Xing, Cedric
2019-07-08 23:53         ` Casey Schaufler
2019-07-09 22:13           ` Xing, Cedric
2019-07-10  0:10             ` Casey Schaufler
2019-07-10  0:55               ` Xing, Cedric
2019-07-10 21:14                 ` Casey Schaufler
2019-07-11 13:51                 ` Stephen Smalley
2019-07-11 15:12                   ` Sean Christopherson
2019-07-11 16:11                     ` Stephen Smalley
2019-07-11 16:25                       ` Sean Christopherson
2019-07-11 16:32                         ` Stephen Smalley
2019-07-11 23:41                           ` Xing, Cedric
2019-07-07 23:41   ` [RFC PATCH v3 4/4] x86/sgx: Implement SGX specific hooks in SELinux Cedric Xing
2019-07-09  1:33     ` Sean Christopherson
2019-07-09 21:26       ` Xing, Cedric
2019-07-10 15:49     ` Sean Christopherson
2019-07-10 16:08       ` Jethro Beekman
2019-07-10 18:16         ` Xing, Cedric
2019-07-10 17:54       ` Xing, Cedric
2019-06-27 18:56 ` [RFC PATCH v2 1/3] x86/sgx: Add SGX specific LSM hooks Cedric Xing
2019-06-27 22:06   ` Casey Schaufler
2019-06-27 22:52     ` Xing, Cedric
2019-06-27 23:37       ` Casey Schaufler
2019-06-28  0:47         ` Xing, Cedric
2019-06-28 17:22           ` Casey Schaufler
2019-06-28 22:29             ` Xing, Cedric
2019-06-29  1:37             ` Stephen Smalley
2019-06-29 21:35               ` Casey Schaufler
2019-07-01 17:57                 ` Xing, Cedric
2019-07-01 19:53                   ` Casey Schaufler
2019-07-01 21:45                     ` Xing, Cedric
2019-07-01 23:11                       ` Casey Schaufler
2019-07-02  7:42                         ` Xing, Cedric
2019-07-02 15:44                           ` Casey Schaufler
2019-07-03  9:46                             ` Dr. Greg
2019-07-03 15:32                               ` Casey Schaufler
2019-07-07 13:30                                 ` Dr. Greg
2019-07-09  0:02                                   ` Casey Schaufler
2019-07-09  1:52                                     ` Sean Christopherson
2019-07-09 21:16                                       ` Xing, Cedric
2019-07-11 10:22                                     ` Dr. Greg
2019-07-15 22:23                                       ` Andy Lutomirski
2019-06-28 16:37   ` Stephen Smalley
2019-06-28 21:53     ` Xing, Cedric
2019-06-29  1:22       ` Stephen Smalley
2019-07-01 18:02         ` Xing, Cedric
2019-06-29 23:46   ` Andy Lutomirski
2019-07-01 17:11     ` Xing, Cedric
2019-07-01 17:58       ` Andy Lutomirski
2019-07-01 18:31         ` Xing, Cedric
2019-07-01 19:36           ` Andy Lutomirski
2019-07-01 19:56             ` Xing, Cedric
2019-07-02  2:29               ` Andy Lutomirski
2019-07-02  6:35                 ` Xing, Cedric
2019-06-27 18:56 ` [RFC PATCH v2 2/3] x86/sgx: Call LSM hooks from SGX subsystem/module Cedric Xing
2019-06-27 18:56 ` [RFC PATCH v2 3/3] x86/sgx: Implement SGX specific hooks in SELinux Cedric Xing
2019-07-05 16:05 ` [RFC PATCH v4 00/12] security: x86/sgx: SGX vs. LSM Jarkko Sakkinen
2019-07-08 17:29   ` Sean Christopherson
2019-07-08 17:33     ` Xing, Cedric
2019-07-09 16:22     ` Jarkko Sakkinen
2019-07-09 17:09       ` Sean Christopherson
2019-07-09 20:41         ` Xing, Cedric
2019-07-09 22:25           ` Sean Christopherson
2019-07-09 23:11             ` Xing, Cedric
2019-07-10 16:57               ` Sean Christopherson
2019-07-10 20:19         ` Jarkko Sakkinen
2019-07-10 20:31           ` Sean Christopherson
2019-07-11  9:06             ` Jarkko Sakkinen
2019-07-10 22:00           ` Jarkko Sakkinen
2019-07-10 22:16         ` Jarkko Sakkinen
2019-07-10 23:16           ` Xing, Cedric
2019-07-11  9:26             ` Jarkko Sakkinen
2019-07-11 14:32               ` Stephen Smalley
2019-07-11 17:51                 ` Jarkko Sakkinen
2019-07-12  0:08                   ` Xing, Cedric
2019-07-10  1:28     ` Dr. Greg
2019-07-10  2:04       ` Xing, Cedric
2019-07-10  3:21     ` Jethro Beekman

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