From patchwork Sat Oct 3 04:50:52 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11815037 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D88986CB for ; Sat, 3 Oct 2020 04:52:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C787823447 for ; Sat, 3 Oct 2020 04:52:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726029AbgJCEwT (ORCPT ); Sat, 3 Oct 2020 00:52:19 -0400 Received: from mail.kernel.org ([198.145.29.99]:52932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725770AbgJCEvw (ORCPT ); Sat, 3 Oct 2020 00:51:52 -0400 Received: from localhost (83-245-197-237.elisa-laajakaista.fi [83.245.197.237]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 749FE22262; Sat, 3 Oct 2020 04:51:43 +0000 (UTC) From: Jarkko Sakkinen To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jarkko Sakkinen , linux-mm@kvack.org, Andrew Morton , Matthew Wilcox , Jethro Beekman , andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, luto@kernel.org, nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com, rientjes@google.com, sean.j.christopherson@intel.com, tglx@linutronix.de, yaozhangx@google.com, mikko.ylinen@intel.com Subject: [PATCH v39 17/24] x86/sgx: Add ptrace() support for the SGX driver Date: Sat, 3 Oct 2020 07:50:52 +0300 Message-Id: <20201003045059.665934-18-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201003045059.665934-1-jarkko.sakkinen@linux.intel.com> References: <20201003045059.665934-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Intel Sofware Guard eXtensions (SGX) allows creation of executable blobs called enclaves, which cannot be accessed by default when not executing inside the enclave. Enclaves can be entered by only using predefined memory addresses, which are defined when the enclave is loaded. However, enclaves can defined as debug enclaves at the load time. In debug enclaves data can be read and/or written a memory word at a time by by using ENCLS[EDBGRD] and ENCLS[EDBGWR] leaf instructions. Add sgx_vma_access() function that implements 'access' virtual function of struct vm_operations_struct. Use aforementioned leaf instructions to provide read and write primitives for the enclave memory. Cc: linux-mm@kvack.org Cc: Andrew Morton Cc: Matthew Wilcox Acked-by: Jethro Beekman Signed-off-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/sgx/encl.c | 89 ++++++++++++++++++++++++++++++++++ 1 file changed, 89 insertions(+) diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 54326efa6c2f..ae45f8f0951e 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -337,10 +337,99 @@ static int sgx_vma_mprotect(struct vm_area_struct *vma, return mprotect_fixup(vma, pprev, start, end, newflags); } +static int sgx_encl_debug_read(struct sgx_encl *encl, struct sgx_encl_page *page, + unsigned long addr, void *data) +{ + unsigned long offset = addr & ~PAGE_MASK; + int ret; + + + ret = __edbgrd(sgx_get_epc_addr(page->epc_page) + offset, data); + if (ret) + return -EIO; + + return 0; +} + +static int sgx_encl_debug_write(struct sgx_encl *encl, struct sgx_encl_page *page, + unsigned long addr, void *data) +{ + unsigned long offset = addr & ~PAGE_MASK; + int ret; + + ret = __edbgwr(sgx_get_epc_addr(page->epc_page) + offset, data); + if (ret) + return -EIO; + + return 0; +} + +static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr, + void *buf, int len, int write) +{ + struct sgx_encl *encl = vma->vm_private_data; + struct sgx_encl_page *entry = NULL; + char data[sizeof(unsigned long)]; + unsigned long align; + unsigned int flags; + int offset; + int cnt; + int ret = 0; + int i; + + /* + * If process was forked, VMA is still there but vm_private_data is set + * to NULL. + */ + if (!encl) + return -EFAULT; + + flags = atomic_read(&encl->flags); + + if (!(flags & SGX_ENCL_DEBUG) || !(flags & SGX_ENCL_INITIALIZED) || + (flags & SGX_ENCL_DEAD)) + return -EFAULT; + + for (i = 0; i < len; i += cnt) { + entry = sgx_encl_reserve_page(encl, (addr + i) & PAGE_MASK); + if (IS_ERR(entry)) { + ret = PTR_ERR(entry); + break; + } + + align = ALIGN_DOWN(addr + i, sizeof(unsigned long)); + offset = (addr + i) & (sizeof(unsigned long) - 1); + cnt = sizeof(unsigned long) - offset; + cnt = min(cnt, len - i); + + ret = sgx_encl_debug_read(encl, entry, align, data); + if (ret) + goto out; + + if (write) { + memcpy(data + offset, buf + i, cnt); + ret = sgx_encl_debug_write(encl, entry, align, data); + if (ret) + goto out; + } else { + memcpy(buf + i, data + offset, cnt); + } + +out: + mutex_unlock(&encl->lock); + + if (ret) + break; + } + + return ret < 0 ? ret : i; +} + const struct vm_operations_struct sgx_vm_ops = { .open = sgx_vma_open, .fault = sgx_vma_fault, .mprotect = sgx_vma_mprotect, + .access = sgx_vma_access, }; /**