From: Borislav Petkov <bp@alien8.de>
To: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
linux-sgx@vger.kernel.org, akpm@linux-foundation.org,
dave.hansen@intel.com, sean.j.christopherson@intel.com,
nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com,
shay.katz-zamir@intel.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
Subject: Re: [PATCH v22 10/24] x86/sgx: Add sgx_einit() for wrapping ENCLS[EINIT]
Date: Tue, 8 Oct 2019 19:30:35 +0200 [thread overview]
Message-ID: <20191008173035.GK14765@zn.tnic> (raw)
In-Reply-To: <20190903142655.21943-11-jarkko.sakkinen@linux.intel.com>
On Tue, Sep 03, 2019 at 05:26:41PM +0300, Jarkko Sakkinen wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
>
> Enclaves are SGX hosted measured and signed software entities. ENCLS[EINIT]
SGX-hosted, measured, and ...
> leaf function checks that the enclave has a legit signed measurement and
> transforms the enclave to the state ready for execution. The signed
> measurement is provided by the caller in the form of SIGSTRUCT data
> structure [1].
>
> Wrap ENCLS[EINIT] into sgx_einit(). Set MSR_IA32_SGXLEPUBKEYHASH* MSRs to
> match the public key contained in the SIGSTRUCT [2]. This sets Linux to
> enforce a policy where the provided public key is as long as the signed
> measurement matches the enclave contents in memory.
That subclause needs to be separated, maybe:
... the provided public key is - as long as the signed measurement
matches the the enclave contents - in memory.
Provided you mean that, of course.
> Add a per-cpu cache to avoid unnecessary reads and write to the MSRs
reads and writes?
> as they are expensive operations.
>
> [1] Intel SDM: 37.1.3 ENCLAVE SIGNATURE STRUCTURE (SIGSTRUCT)
> [2] Intel SDM: 38.1.4 Intel SGX Launch Control Configuration
>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Co-developed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
> ---
> arch/x86/kernel/cpu/sgx/main.c | 51 ++++++++++++++++++++++++++++++++++
> arch/x86/kernel/cpu/sgx/sgx.h | 2 ++
> 2 files changed, 53 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
> index 6b4727df72ca..d3ed742e90fe 100644
> --- a/arch/x86/kernel/cpu/sgx/main.c
> +++ b/arch/x86/kernel/cpu/sgx/main.c
> @@ -17,6 +17,9 @@ EXPORT_SYMBOL_GPL(sgx_epc_sections);
>
> int sgx_nr_epc_sections;
>
> +/* A per-cpu cache for the last known values of IA32_SGXLEPUBKEYHASHx MSRs. */
> +static DEFINE_PER_CPU(u64 [4], sgx_lepubkeyhash_cache);
> +
> static struct sgx_epc_page *sgx_section_get_page(
> struct sgx_epc_section *section)
> {
> @@ -106,6 +109,54 @@ void sgx_free_page(struct sgx_epc_page *page)
> }
> EXPORT_SYMBOL_GPL(sgx_free_page);
>
> +static void sgx_update_lepubkeyhash_msrs(u64 *lepubkeyhash, bool enforce)
> +{
> + u64 *cache;
> + int i;
> +
> + cache = per_cpu(sgx_lepubkeyhash_cache, smp_processor_id());
> + for (i = 0; i < 4; i++) {
> + if (enforce || (lepubkeyhash[i] != cache[i])) {
> + wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
> + cache[i] = lepubkeyhash[i];
> + }
> + }
> +}
> +
> +/**
> + * sgx_einit - initialize an enclave
> + * @sigstruct: a pointer a SIGSTRUCT
> + * @token: a pointer an EINITTOKEN (optional)
> + * @secs: a pointer a SECS
That's a strange formulation "a pointer a/an" ? "to" missing?
> + * @lepubkeyhash: the desired value for IA32_SGXLEPUBKEYHASHx MSRs
> + *
> + * Execute ENCLS[EINIT], writing the IA32_SGXLEPUBKEYHASHx MSRs according
> + * to @lepubkeyhash (if possible and necessary).
> + *
> + * Return:
> + * 0 on success,
> + * -errno or SGX error on failure
> + */
> +int sgx_einit(struct sgx_sigstruct *sigstruct, struct sgx_einittoken *token,
> + struct sgx_epc_page *secs, u64 *lepubkeyhash)
> +{
> + int ret;
> +
> + if (!boot_cpu_has(X86_FEATURE_SGX_LC))
> + return __einit(sigstruct, token, sgx_epc_addr(secs));
> +
> + preempt_disable();
> + sgx_update_lepubkeyhash_msrs(lepubkeyhash, false);
> + ret = __einit(sigstruct, token, sgx_epc_addr(secs));
> + if (ret == SGX_INVALID_EINITTOKEN) {
> + sgx_update_lepubkeyhash_msrs(lepubkeyhash, true);
> + ret = __einit(sigstruct, token, sgx_epc_addr(secs));
> + }
> + preempt_enable();
> + return ret;
> +}
> +EXPORT_SYMBOL(sgx_einit);
I was about to ask why isn't this export _GPL() but it goes away in a
later patch.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next prev parent reply other threads:[~2019-10-08 17:30 UTC|newest]
Thread overview: 102+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-03 14:26 [PATCH v22 00/24] Intel SGX foundations Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 01/24] x86/cpufeatures: x86/msr: Add Intel SGX hardware bits Jarkko Sakkinen
2019-09-24 15:28 ` Borislav Petkov
2019-09-24 16:11 ` Sean Christopherson
2019-09-24 16:25 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 02/24] x86/cpufeatures: x86/msr: Intel SGX Launch Control " Jarkko Sakkinen
2019-09-24 15:52 ` Borislav Petkov
2019-09-24 20:22 ` Sean Christopherson
2019-09-25 8:51 ` Borislav Petkov
2019-09-25 17:18 ` Sean Christopherson
2019-09-25 18:31 ` Borislav Petkov
2019-09-25 19:08 ` Sean Christopherson
2019-09-27 16:11 ` Jarkko Sakkinen
2019-09-25 14:09 ` Jarkko Sakkinen
2019-09-25 14:10 ` Jarkko Sakkinen
2019-09-25 14:38 ` Jarkko Sakkinen
2019-09-25 15:19 ` Borislav Petkov
2019-09-25 16:49 ` Sean Christopherson
2019-09-25 17:28 ` Borislav Petkov
2019-09-25 18:18 ` Sean Christopherson
2019-09-03 14:26 ` [PATCH v22 03/24] x86/mm: x86/sgx: Signal SIGSEGV with PF_SGX Jarkko Sakkinen
2019-09-24 16:04 ` Borislav Petkov
2019-09-25 14:16 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 04/24] x86/cpu/intel: Detect SGX supprt Jarkko Sakkinen
2019-09-24 16:13 ` Borislav Petkov
2019-09-24 17:43 ` Sean Christopherson
2019-09-24 18:21 ` Borislav Petkov
2019-09-25 14:46 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 05/24] x86/sgx: Add ENCLS architectural error codes Jarkko Sakkinen
2019-09-27 10:20 ` Borislav Petkov
2019-09-27 16:08 ` Jarkko Sakkinen
2019-09-27 17:20 ` Sean Christopherson
2019-10-01 20:23 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 06/24] x86/sgx: Add SGX microarchitectural data structures Jarkko Sakkinen
2019-09-27 16:27 ` Borislav Petkov
2019-10-01 19:10 ` Jarkko Sakkinen
2019-10-01 20:39 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 07/24] x86/sgx: Add wrappers for ENCLS leaf functions Jarkko Sakkinen
2019-10-04 9:45 ` Borislav Petkov
2019-10-04 18:56 ` Jarkko Sakkinen
2019-10-08 4:04 ` Sean Christopherson
2019-10-08 7:18 ` Borislav Petkov
2019-10-08 13:35 ` Sean Christopherson
2019-10-08 14:56 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 08/24] x86/sgx: Enumerate and track EPC sections Jarkko Sakkinen
2019-10-05 9:26 ` Borislav Petkov
2019-10-07 11:58 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 09/24] x86/sgx: Add functions to allocate and free EPC pages Jarkko Sakkinen
2019-10-05 16:44 ` Borislav Petkov
2019-10-07 14:50 ` Sean Christopherson
2019-10-08 9:09 ` Borislav Petkov
2019-10-08 13:31 ` Sean Christopherson
2019-10-07 17:55 ` Jarkko Sakkinen
2019-10-07 18:09 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 10/24] x86/sgx: Add sgx_einit() for wrapping ENCLS[EINIT] Jarkko Sakkinen
2019-10-08 17:30 ` Borislav Petkov [this message]
2019-10-08 17:45 ` Sean Christopherson
2019-10-08 17:46 ` Sean Christopherson
2019-10-08 17:53 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 11/24] mm: Introduce vm_ops->may_mprotect() Jarkko Sakkinen
2019-10-08 17:41 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 12/24] x86/sgx: Linux Enclave Driver Jarkko Sakkinen
2019-10-08 17:59 ` Borislav Petkov
2019-10-08 18:17 ` Sean Christopherson
2019-10-08 19:19 ` Borislav Petkov
2019-09-03 14:26 ` [PATCH v22 13/24] x86/sgx: Add provisioning Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 14/24] x86/sgx: Add a page reclaimer Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 15/24] x86/sgx: ptrace() support for the SGX driver Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 16/24] x86/vdso: Add support for exception fixup in vDSO functions Jarkko Sakkinen
2019-10-02 23:18 ` Jarkko Sakkinen
2019-10-02 23:45 ` Jarkko Sakkinen
2019-10-04 0:03 ` Sean Christopherson
2019-10-04 18:49 ` Jarkko Sakkinen
2019-10-04 0:15 ` Sean Christopherson
2019-10-04 18:52 ` Jarkko Sakkinen
2019-10-05 15:54 ` Sean Christopherson
2019-10-07 7:57 ` Jarkko Sakkinen
2019-10-07 8:10 ` Jarkko Sakkinen
2019-10-07 12:04 ` Jarkko Sakkinen
2019-10-08 4:54 ` Sean Christopherson
2019-10-05 18:39 ` Sean Christopherson
2019-10-07 8:01 ` Jarkko Sakkinen
2019-10-06 23:38 ` Jarkko Sakkinen
2019-10-06 23:40 ` Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 17/24] x86/fault: Add helper function to sanitize error code Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 18/24] x86/traps: Attempt to fixup exceptions in vDSO before signaling Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 19/24] x86/vdso: Add __vdso_sgx_enter_enclave() to wrap SGX enclave transitions Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 20/24] selftests/x86: Add a selftest for SGX Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 21/24] selftests/x86: Recurse into subdirectories Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 22/24] x86/sgx: Update MAINTAINERS Jarkko Sakkinen
2019-09-03 14:26 ` [PATCH v22 23/24] docs: x86/sgx: Document microarchitecture Jarkko Sakkinen
2019-09-27 18:15 ` Randy Dunlap
2019-09-03 14:26 ` [PATCH v22 24/24] docs: x86/sgx: Document kernel internals Jarkko Sakkinen
2019-09-27 17:07 ` Randy Dunlap
2019-10-01 19:34 ` Jarkko Sakkinen
2019-09-13 20:38 ` [PATCH v22 00/24] Intel SGX foundations Dave Hansen
2019-09-14 13:41 ` Jarkko Sakkinen
2019-09-14 15:32 ` Dave Hansen
2019-09-16 5:23 ` Jarkko Sakkinen
2019-09-24 17:20 ` Andy Lutomirski
2019-09-25 14:32 ` Jarkko Sakkinen
2019-10-02 23:42 ` Jarkko Sakkinen
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