From patchwork Thu Jun 27 18:56:20 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: "Xing, Cedric" X-Patchwork-Id: 11020297 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 2D5B71932 for ; Thu, 27 Jun 2019 18:56:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 22F5D26E4A for ; Thu, 27 Jun 2019 18:56:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1684B286E5; Thu, 27 Jun 2019 18:56:31 +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=unavailable 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 1271126E4A for ; Thu, 27 Jun 2019 18:56:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726508AbfF0S42 (ORCPT ); Thu, 27 Jun 2019 14:56:28 -0400 Received: from mga12.intel.com ([192.55.52.136]:10286 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726384AbfF0S41 (ORCPT ); Thu, 27 Jun 2019 14:56:27 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 27 Jun 2019 11:56:26 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,424,1557212400"; d="scan'208";a="361259291" Received: from bxing-desk.ccr.corp.intel.com (HELO ubt18.jf.intel.com) ([134.134.148.187]) by fmsmga006.fm.intel.com with ESMTP; 27 Jun 2019 11:56:26 -0700 From: Cedric Xing To: linux-sgx@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@vger.kernel.org, cedric.xing@intel.com Cc: casey.schaufler@intel.com, jmorris@namei.org, luto@kernel.org, jethro@fortanix.com, greg@enjellic.com, sds@tycho.nsa.gov, jarkko.sakkinen@linux.intel.com, sean.j.christopherson@intel.com Subject: [RFC PATCH v2 2/3] x86/sgx: Call LSM hooks from SGX subsystem/module Date: Thu, 27 Jun 2019 11:56:20 -0700 Message-Id: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: <20190619222401.14942-1-sean.j.christopherson@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 It’s straightforward to call new LSM hooks from the SGX subsystem/module. There are three places where LSM hooks are invoked. 1) sgx_mmap() invokes security_file_mprotect() to validate requested protection. It is necessary because security_mmap_file() invoked by mmap() syscall only validates protections against /dev/sgx/enclave file, but not against those files from which the pages were loaded from. 2) security_enclave_load() is invoked upon loading of every enclave page by the EADD ioctl. Please note that if pages are EADD’ed in batch, the SGX subsystem/module is responsible for dividing pages in trunks so that each trunk is loaded from a single VMA. 3) security_enclave_init() is invoked before initializing (EINIT) every enclave. Signed-off-by: Cedric Xing --- arch/x86/kernel/cpu/sgx/driver/ioctl.c | 80 +++++++++++++++++++++++--- arch/x86/kernel/cpu/sgx/driver/main.c | 16 +++++- 2 files changed, 85 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/driver/ioctl.c b/arch/x86/kernel/cpu/sgx/driver/ioctl.c index b186fb7b48d5..4f5abf9819a7 100644 --- a/arch/x86/kernel/cpu/sgx/driver/ioctl.c +++ b/arch/x86/kernel/cpu/sgx/driver/ioctl.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) // Copyright(c) 2016-19 Intel Corporation. -#include +#include #include #include #include @@ -11,6 +11,7 @@ #include #include #include +#include #include "driver.h" struct sgx_add_page_req { @@ -575,6 +576,46 @@ static int sgx_encl_add_page(struct sgx_encl *encl, unsigned long addr, return ret; } +static int sgx_encl_prepare_page(struct file *filp, unsigned long dst, + unsigned long src, void *buf) +{ + struct vm_area_struct *vma; + unsigned long prot; + int rc; + + if (dst & ~PAGE_SIZE) + return -EINVAL; + + rc = down_read_killable(¤t->mm->mmap_sem); + if (rc) + return rc; + + vma = find_vma(current->mm, dst); + if (vma && dst >= vma->vm_start) + prot = _calc_vm_trans(vma->vm_flags, VM_READ, PROT_READ) | + _calc_vm_trans(vma->vm_flags, VM_WRITE, PROT_WRITE) | + _calc_vm_trans(vma->vm_flags, VM_EXEC, PROT_EXEC); + else + prot = 0; + + vma = find_vma(current->mm, src); + if (!vma || src < vma->vm_start || src + PAGE_SIZE > vma->vm_end) + rc = -EFAULT; + + if (!rc && !(vma->vm_flags & VM_MAYEXEC)) + rc = -EACCES; + + if (!rc && copy_from_user(buf, (void __user *)src, PAGE_SIZE)) + rc = -EFAULT; + + if (!rc) + rc = security_enclave_load(filp, dst, PAGE_SIZE, prot, vma); + + up_read(¤t->mm->mmap_sem); + + return rc; +} + /** * sgx_ioc_enclave_add_page - handler for %SGX_IOC_ENCLAVE_ADD_PAGE * @@ -613,10 +654,9 @@ static long sgx_ioc_enclave_add_page(struct file *filep, unsigned int cmd, data = kmap(data_page); - if (copy_from_user((void *)data, (void __user *)addp->src, PAGE_SIZE)) { - ret = -EFAULT; + ret = sgx_encl_prepare_page(filep, addp->addr, addp->src, data); + if (ret) goto out; - } ret = sgx_encl_add_page(encl, addp->addr, data, &secinfo, addp->mrmask); if (ret) @@ -718,6 +758,31 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct, return ret; } +static int sgx_encl_prepare_sigstruct(struct file *filp, unsigned long src, + struct sgx_sigstruct *ss) +{ + struct vm_area_struct *vma; + int rc; + + rc = down_read_killable(¤t->mm->mmap_sem); + if (rc) + return rc; + + vma = find_vma(current->mm, src); + if (!vma || src < vma->vm_start || src + sizeof(*ss) > vma->vm_end) + rc = -EFAULT; + + if (!rc && copy_from_user(ss, (void __user *)src, sizeof(*ss))) + rc = -EFAULT; + + if (!rc) + rc = security_enclave_init(filp, ss, vma); + + up_read(¤t->mm->mmap_sem); + + return rc; +} + /** * sgx_ioc_enclave_init - handler for %SGX_IOC_ENCLAVE_INIT * @@ -753,12 +818,9 @@ static long sgx_ioc_enclave_init(struct file *filep, unsigned int cmd, ((unsigned long)sigstruct + PAGE_SIZE / 2); memset(einittoken, 0, sizeof(*einittoken)); - if (copy_from_user(sigstruct, (void __user *)initp->sigstruct, - sizeof(*sigstruct))) { - ret = -EFAULT; + ret = sgx_encl_prepare_sigstruct(filep, initp->sigstruct, sigstruct); + if (ret) goto out; - } - ret = sgx_encl_init(encl, sigstruct, einittoken); diff --git a/arch/x86/kernel/cpu/sgx/driver/main.c b/arch/x86/kernel/cpu/sgx/driver/main.c index afe844aa81d6..95fe18c37b84 100644 --- a/arch/x86/kernel/cpu/sgx/driver/main.c +++ b/arch/x86/kernel/cpu/sgx/driver/main.c @@ -63,14 +63,26 @@ static long sgx_compat_ioctl(struct file *filep, unsigned int cmd, static int sgx_mmap(struct file *file, struct vm_area_struct *vma) { struct sgx_encl *encl = file->private_data; + unsigned long prot; + int rc; vma->vm_ops = &sgx_vm_ops; vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO; vma->vm_private_data = encl; - kref_get(&encl->refcount); + prot = vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC); + vma->vm_flags &= ~prot; - return 0; + prot = _calc_vm_trans(prot, VM_READ, PROT_READ) | + _calc_vm_trans(prot, VM_WRITE, PROT_WRITE) | + _calc_vm_trans(prot, VM_EXEC, PROT_EXEC); + rc = security_file_mprotect(vma, prot, prot); + if (!rc) { + vma->vm_flags |= calc_vm_prot_bits(prot, 0); + kref_get(&encl->refcount); + } + + return rc; } static unsigned long sgx_get_unmapped_area(struct file *file,