From patchwork Tue May 10 18:08:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 12845394 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 786D7C433F5 for ; Tue, 10 May 2022 18:09:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348536AbiEJSN2 (ORCPT ); Tue, 10 May 2022 14:13:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58114 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1348541AbiEJSNT (ORCPT ); Tue, 10 May 2022 14:13:19 -0400 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8DC129C8B; Tue, 10 May 2022 11:09:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1652206161; x=1683742161; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=B0KUtzhdPV9j7URFLi7gBgZGctuhFZQXMtJCJ0bOjjc=; b=i+k5NK5pH5UNGfahK/5i+uclAh60LR1nXQWrjebpTtXsrqF+RvtJOrLe 6KzcIRzYZUXiWWLR+06Trw3yKcABpuspQFNgUR7Ab2M8TJOfb3vl8Zh5h yHY7JHMpwYCpWTG19+VdzC8ip95XP1NeBhh7u9cGWslvZu+VECE6YmOk5 FLbdoy3HHzTSQEU28JNdKinI0cPqrqhAOm4MZgYCiGFREBE/K+eulNbdK ZGw5qtEs+B5VYTjnV8aqqG8t7BVLhTmN8zAOzWZ30bjLoiSFwdAoMlOnS VA743NMYSarAv00GqGCrqn3/G33lv5mO9SO0GEXyrTCeyBQWWH2YamHxn A==; X-IronPort-AV: E=McAfee;i="6400,9594,10343"; a="330057507" X-IronPort-AV: E=Sophos;i="5.91,214,1647327600"; d="scan'208";a="330057507" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2022 11:09:16 -0700 X-IronPort-AV: E=Sophos;i="5.91,214,1647327600"; d="scan'208";a="541908754" Received: from rchatre-ws.ostc.intel.com ([10.54.69.144]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 10 May 2022 11:09:16 -0700 From: Reinette Chatre To: dave.hansen@linux.intel.com, jarkko@kernel.org, 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: [PATCH V5 05/31] x86/sgx: Support loading enclave page without VMA permissions check Date: Tue, 10 May 2022 11:08:41 -0700 Message-Id: X-Mailer: git-send-email 2.25.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org sgx_encl_load_page() is used to find and load an enclave page into enclave (EPC) memory, potentially loading it from the backing storage. Both usages of sgx_encl_load_page() are during an access to the enclave page from a VMA and thus the permissions of the VMA are considered before the enclave page is loaded. SGX2 functions operating on enclave pages belonging to an initialized enclave requiring the page to be in EPC. It is thus required to support loading enclave pages into the EPC independent from a VMA. Split the current sgx_encl_load_page() to support the two usages: A new call, sgx_encl_load_page_in_vma(), behaves exactly like the current sgx_encl_load_page() that takes VMA permissions into account, while sgx_encl_load_page() just loads an enclave page into EPC. VMA, PTE, and EPCM permissions continue to dictate whether the pages can be accessed from within an enclave. Reviewed-by: Jarkko Sakkinen Signed-off-by: Reinette Chatre --- No changes since V4. Changes since V3: - Add Jarkko's Reviewed-by tag. Changes since V2: - New patch arch/x86/kernel/cpu/sgx/encl.c | 57 ++++++++++++++++++++++------------ arch/x86/kernel/cpu/sgx/encl.h | 2 ++ 2 files changed, 40 insertions(+), 19 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index af972dbad965..7217c492e103 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -227,25 +227,10 @@ static struct sgx_epc_page *sgx_encl_eldu(struct sgx_encl_page *encl_page, return epc_page; } -static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl, - unsigned long addr, - unsigned long vm_flags) +static struct sgx_encl_page *__sgx_encl_load_page(struct sgx_encl *encl, + struct sgx_encl_page *entry) { - unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC); struct sgx_epc_page *epc_page; - struct sgx_encl_page *entry; - - entry = xa_load(&encl->page_array, PFN_DOWN(addr)); - if (!entry) - return ERR_PTR(-EFAULT); - - /* - * Verify that the faulted page has equal or higher build time - * permissions than the VMA permissions (i.e. the subset of {VM_READ, - * VM_WRITE, VM_EXECUTE} in vma->vm_flags). - */ - if ((entry->vm_max_prot_bits & vm_prot_bits) != vm_prot_bits) - return ERR_PTR(-EFAULT); /* Entry successfully located. */ if (entry->epc_page) { @@ -271,6 +256,40 @@ static struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl, return entry; } +static struct sgx_encl_page *sgx_encl_load_page_in_vma(struct sgx_encl *encl, + unsigned long addr, + unsigned long vm_flags) +{ + unsigned long vm_prot_bits = vm_flags & (VM_READ | VM_WRITE | VM_EXEC); + struct sgx_encl_page *entry; + + entry = xa_load(&encl->page_array, PFN_DOWN(addr)); + if (!entry) + return ERR_PTR(-EFAULT); + + /* + * Verify that the page has equal or higher build time + * permissions than the VMA permissions (i.e. the subset of {VM_READ, + * VM_WRITE, VM_EXECUTE} in vma->vm_flags). + */ + if ((entry->vm_max_prot_bits & vm_prot_bits) != vm_prot_bits) + return ERR_PTR(-EFAULT); + + return __sgx_encl_load_page(encl, entry); +} + +struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl, + unsigned long addr) +{ + struct sgx_encl_page *entry; + + entry = xa_load(&encl->page_array, PFN_DOWN(addr)); + if (!entry) + return ERR_PTR(-EFAULT); + + return __sgx_encl_load_page(encl, entry); +} + static vm_fault_t sgx_vma_fault(struct vm_fault *vmf) { unsigned long addr = (unsigned long)vmf->address; @@ -292,7 +311,7 @@ static vm_fault_t sgx_vma_fault(struct vm_fault *vmf) mutex_lock(&encl->lock); - entry = sgx_encl_load_page(encl, addr, vma->vm_flags); + entry = sgx_encl_load_page_in_vma(encl, addr, vma->vm_flags); if (IS_ERR(entry)) { mutex_unlock(&encl->lock); @@ -440,7 +459,7 @@ static struct sgx_encl_page *sgx_encl_reserve_page(struct sgx_encl *encl, for ( ; ; ) { mutex_lock(&encl->lock); - entry = sgx_encl_load_page(encl, addr, vm_flags); + entry = sgx_encl_load_page_in_vma(encl, addr, vm_flags); if (PTR_ERR(entry) != -EBUSY) break; diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h index d44e7372151f..522a17e4fd2d 100644 --- a/arch/x86/kernel/cpu/sgx/encl.h +++ b/arch/x86/kernel/cpu/sgx/encl.h @@ -116,5 +116,7 @@ unsigned int sgx_alloc_va_slot(struct sgx_va_page *va_page); void sgx_free_va_slot(struct sgx_va_page *va_page, unsigned int offset); bool sgx_va_page_full(struct sgx_va_page *va_page); void sgx_encl_free_epc_page(struct sgx_epc_page *page); +struct sgx_encl_page *sgx_encl_load_page(struct sgx_encl *encl, + unsigned long addr); #endif /* _X86_ENCL_H */