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From: Jarkko Sakkinen <jarkko@kernel.org>
To: Reinette Chatre <reinette.chatre@intel.com>,
	dave.hansen@linux.intel.com, tglx@linutronix.de, bp@alien8.de,
	luto@kernel.org, mingo@redhat.com, linux-sgx@vger.kernel.org,
	x86@kernel.org, shuah@kernel.org,
	linux-kselftest@vger.kernel.org
Cc: seanjc@google.com, kai.huang@intel.com, cathy.zhang@intel.com,
	cedric.xing@intel.com, haitao.huang@intel.com,
	mark.shanahan@intel.com, vijay.dhanraj@intel.com, hpa@zytor.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH V4 15/31] x86/sgx: Support restricting of enclave page permissions
Date: Thu, 14 Apr 2022 14:19:00 +0300	[thread overview]
Message-ID: <9abbecc124d61843c27217bf183d7447a281c297.camel@kernel.org> (raw)
In-Reply-To: <a1d7820ab5f2e6d21cacb14bafd40a682101c492.1649878359.git.reinette.chatre@intel.com>

On Wed, 2022-04-13 at 14:10 -0700, Reinette Chatre wrote:
> In the initial (SGX1) version of SGX, pages in an enclave need to be
> created with permissions that support all usages of the pages, from the
> time the enclave is initialized until it is unloaded. For example,
> pages used by a JIT compiler or when code needs to otherwise be
> relocated need to always have RWX permissions.
> 
> SGX2 includes a new function ENCLS[EMODPR] that is run from the kernel
> and can be used to restrict the EPCM permissions of regular enclave
> pages within an initialized enclave.
> 
> Introduce ioctl() SGX_IOC_ENCLAVE_RESTRICT_PERMISSIONS to support
> restricting EPCM permissions. With this ioctl() the user specifies
> a page range and the EPCM permissions to be applied to all pages in
> the provided range. ENCLS[EMODPR] is run to restrict the EPCM
> permissions followed by the ENCLS[ETRACK] flow that will ensure
> no cached linear-to-physical address mappings to the changed
> pages remain.
> 
> It is possible for the permission change request to fail on any
> page within the provided range, either with an error encountered
> by the kernel or by the SGX hardware while running
> ENCLS[EMODPR]. To support partial success the ioctl() returns an
> error code based on failures encountered by the kernel as well
> as two result output parameters: one for the number of pages
> that were successfully changed and one for the SGX return code.
> 
> The page table entry permissions are not impacted by the EPCM
> permission changes. VMAs and PTEs will continue to allow the
> maximum vetted permissions determined at the time the pages
> are added to the enclave. The SGX error code in a page fault
> will indicate if it was an EPCM permission check that prevented
> an access attempt.
> 
> No checking is done to ensure that the permissions are actually
> being restricted. This is because the enclave may have relaxed
> the EPCM permissions from within the enclave without the kernel
> knowing. An attempt to relax permissions using this call will
> be ignored by the hardware.
> 
> Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>

Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>

BR, Jarkko

  reply	other threads:[~2022-04-14 11:20 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-13 21:10 [PATCH V4 00/31] x86/sgx and selftests/sgx: Support SGX2 Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 01/31] x86/sgx: Add short descriptions to ENCLS wrappers Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 02/31] x86/sgx: Add wrapper for SGX2 EMODPR function Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 03/31] x86/sgx: Add wrapper for SGX2 EMODT function Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 04/31] x86/sgx: Add wrapper for SGX2 EAUG function Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 05/31] x86/sgx: Support loading enclave page without VMA permissions check Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 06/31] x86/sgx: Export sgx_encl_ewb_cpumask() Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 07/31] x86/sgx: Rename sgx_encl_ewb_cpumask() as sgx_encl_cpumask() Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 08/31] x86/sgx: Move PTE zap code to new sgx_zap_enclave_ptes() Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 09/31] x86/sgx: Make sgx_ipi_cb() available internally Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 10/31] x86/sgx: Create utility to validate user provided offset and length Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 11/31] x86/sgx: Keep record of SGX page type Reinette Chatre
2022-04-14 11:12   ` Jarkko Sakkinen
2022-04-14 16:27     ` Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 12/31] x86/sgx: Export sgx_encl_{grow,shrink}() Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 13/31] x86/sgx: Export sgx_encl_page_alloc() Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 14/31] x86/sgx: Support VA page allocation without reclaiming Reinette Chatre
2022-04-14 11:18   ` Jarkko Sakkinen
2022-04-14 16:30     ` Reinette Chatre
2022-04-15 13:54       ` Haitao Huang
2022-04-15 15:22         ` Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 15/31] x86/sgx: Support restricting of enclave page permissions Reinette Chatre
2022-04-14 11:19   ` Jarkko Sakkinen [this message]
2022-04-14 11:19     ` Jarkko Sakkinen
2022-04-14 16:31       ` Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 16/31] x86/sgx: Support adding of pages to an initialized enclave Reinette Chatre
2022-04-14 11:20   ` Jarkko Sakkinen
2022-04-14 16:31     ` Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 17/31] x86/sgx: Tighten accessible memory range after enclave initialization Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 18/31] x86/sgx: Support modifying SGX page type Reinette Chatre
2022-04-14 11:11   ` Jarkko Sakkinen
2022-04-14 16:32     ` Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 19/31] x86/sgx: Support complete page removal Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 20/31] x86/sgx: Free up EPC pages directly to support large page ranges Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 21/31] Documentation/x86: Introduce enclave runtime management section Reinette Chatre
2022-04-14 11:21   ` Jarkko Sakkinen
2022-04-14 16:32     ` Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 22/31] selftests/sgx: Add test for EPCM permission changes Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 23/31] selftests/sgx: Add test for TCS page " Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 24/31] selftests/sgx: Test two different SGX2 EAUG flows Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 25/31] selftests/sgx: Introduce dynamic entry point Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 26/31] selftests/sgx: Introduce TCS initialization enclave operation Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 27/31] selftests/sgx: Test complete changing of page type flow Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 28/31] selftests/sgx: Test faulty enclave behavior Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 29/31] selftests/sgx: Test invalid access to removed enclave page Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 30/31] selftests/sgx: Test reclaiming of untouched page Reinette Chatre
2022-04-13 21:10 ` [PATCH V4 31/31] selftests/sgx: Page removal stress test Reinette Chatre
2022-04-14 11:25 ` [PATCH V4 00/31] x86/sgx and selftests/sgx: Support SGX2 Jarkko Sakkinen
2022-04-14 16:34   ` Reinette Chatre
2022-04-14 16:55     ` Jarkko Sakkinen
2022-04-14 18:35       ` Dhanraj, Vijay
2022-04-17 14:58         ` Jarkko Sakkinen
2022-04-21 23:46           ` Dhanraj, Vijay
2022-04-22  3:29             ` Reinette Chatre
2022-04-22  9:16               ` Jarkko Sakkinen
2022-04-22 13:17                 ` Jarkko Sakkinen
2022-04-25 20:17                 ` Dhanraj, Vijay
2022-04-25 23:56                   ` Reinette Chatre
2022-04-26  4:10                     ` Jarkko Sakkinen
2022-04-22  9:14             ` Jarkko Sakkinen

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