From patchwork Mon Aug 19 15:25:40 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11101281 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 1D2F0174A for ; Mon, 19 Aug 2019 15:25:56 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0D12A28396 for ; Mon, 19 Aug 2019 15:25:56 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 00D43287ED; Mon, 19 Aug 2019 15:25:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 92AB128396 for ; Mon, 19 Aug 2019 15:25:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726628AbfHSPZz (ORCPT ); Mon, 19 Aug 2019 11:25:55 -0400 Received: from mga14.intel.com ([192.55.52.115]:9895 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726211AbfHSPZz (ORCPT ); Mon, 19 Aug 2019 11:25:55 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Aug 2019 08:25:54 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,405,1559545200"; d="scan'208";a="180393027" Received: from jsakkine-mobl1.tm.intel.com (HELO localhost) ([10.237.50.125]) by orsmga003.jf.intel.com with ESMTP; 19 Aug 2019 08:25:50 -0700 From: Jarkko Sakkinen To: linux-sgx@vger.kernel.org Cc: Jarkko Sakkinen , Sean Christopherson , Shay Katz-zamir , Serge Ayoun Subject: [PATCH 1/5] x86/sgx: Document permission handling better Date: Mon, 19 Aug 2019 18:25:40 +0300 Message-Id: <20190819152544.7296-2-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190819152544.7296-1-jarkko.sakkinen@linux.intel.com> References: <20190819152544.7296-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The way permissions are managed inside the driver is not trivial and intuitive. The non-obvious parts were not properly remarked in the source code. This patch refines them a bit. Cc: Sean Christopherson Cc: Shay Katz-zamir Cc: Serge Ayoun Signed-off-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/sgx/driver/ioctl.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c index 9b784a061a47..64d3286f3324 100644 --- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c @@ -259,7 +259,10 @@ static struct sgx_encl_page *sgx_encl_page_alloc(struct sgx_encl *encl, return ERR_PTR(-ENOMEM); encl_page->desc = addr; encl_page->encl = encl; + + /* Calculate maximum of the VM flags for the page. */ encl_page->vm_prot_bits = calc_vm_prot_bits(prot, 0); + ret = radix_tree_insert(&encl->page_tree, PFN_DOWN(encl_page->desc), encl_page); if (ret) { @@ -640,11 +643,15 @@ static long sgx_ioc_enclave_add_page(struct file *filep, void __user *arg) data = kmap(data_page); + /* Set prot bits matching to the SECINFO permissions. */ prot = _calc_vm_trans(secinfo.flags, SGX_SECINFO_R, PROT_READ) | _calc_vm_trans(secinfo.flags, SGX_SECINFO_W, PROT_WRITE) | _calc_vm_trans(secinfo.flags, SGX_SECINFO_X, PROT_EXEC); - /* TCS pages need to be RW in the PTEs, but can be 0 in the EPCM. */ + /* TCS pages must always RW set for CPU access while the SECINFO + * permissions are *always* zero - the CPU ignores the user provided + * values and silently overwrites zero permissions. + */ if ((secinfo.flags & SGX_SECINFO_PAGE_TYPE_MASK) == SGX_SECINFO_TCS) prot |= PROT_READ | PROT_WRITE;