From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C595EC28CC3 for ; Tue, 4 Jun 2019 15:32:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A9B362190D for ; Tue, 4 Jun 2019 15:32:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728178AbfFDPc1 (ORCPT ); Tue, 4 Jun 2019 11:32:27 -0400 Received: from mga06.intel.com ([134.134.136.31]:2019 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727972AbfFDPc0 (ORCPT ); Tue, 4 Jun 2019 11:32:26 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Jun 2019 08:32:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,550,1549958400"; d="scan'208";a="181589010" Received: from tvuori-mobl1.ger.corp.intel.com (HELO localhost) ([10.251.93.210]) by fmsmga002.fm.intel.com with ESMTP; 04 Jun 2019 08:32:16 -0700 Date: Tue, 4 Jun 2019 18:32:15 +0300 From: Jarkko Sakkinen To: Sean Christopherson Cc: Andy Lutomirski , Cedric Xing , Stephen Smalley , James Morris , "Serge E . Hallyn" , LSM List , Paul Moore , Eric Paris , selinux@vger.kernel.org, Jethro Beekman , Dave Hansen , Thomas Gleixner , Linus Torvalds , LKML , X86 ML , linux-sgx@vger.kernel.org, Andrew Morton , nhorman@redhat.com, npmccallum@redhat.com, Serge Ayoun , Shay Katz-zamir , Haitao Huang , Andy Shevchenko , Kai Svahn , Borislav Petkov , Josh Triplett , Kai Huang , David Rientjes , William Roberts , Philip Tricca Subject: Re: [RFC PATCH 5/9] x86/sgx: Restrict mapping without an enclave page to PROT_NONE Message-ID: <20190604153201.GA3811@linux.intel.com> References: <20190531233159.30992-1-sean.j.christopherson@intel.com> <20190531233159.30992-6-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190531233159.30992-6-sean.j.christopherson@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 31, 2019 at 04:31:55PM -0700, Sean Christopherson wrote: > To support LSM integration, SGX will require userspace to explicitly > specify the allowed protections for each page. The allowed protections > will be supplied to and modified by LSMs (based on their policies). How the allowed protections are modified by LSMs? AFAIK they don't touch the PROT_* flags but I could be wrong too. > To prevent userspace from circumventing the allowed protections, do not > allow PROT_{READ,WRITE,EXEC} mappings to an enclave without an > associated enclave page (which will track the allowed protections). > > Signed-off-by: Sean Christopherson > --- > arch/x86/kernel/cpu/sgx/driver/main.c | 5 +++++ > arch/x86/kernel/cpu/sgx/encl.c | 30 +++++++++++++++++++++++++++ > arch/x86/kernel/cpu/sgx/encl.h | 3 +++ > 3 files changed, 38 insertions(+) > > diff --git a/arch/x86/kernel/cpu/sgx/driver/main.c b/arch/x86/kernel/cpu/sgx/driver/main.c > index 129d356aff30..65a87c2fdf02 100644 > --- a/arch/x86/kernel/cpu/sgx/driver/main.c > +++ b/arch/x86/kernel/cpu/sgx/driver/main.c > @@ -63,6 +63,11 @@ 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; > + int ret; > + > + ret = sgx_map_allowed(encl, vma->vm_start, vma->vm_end, vma->vm_flags); > + if (ret) > + return ret; > > vma->vm_ops = &sgx_vm_ops; > vma->vm_flags |= VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO; > diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c > index f23ea0fbaa47..955d4f430adc 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.c > +++ b/arch/x86/kernel/cpu/sgx/encl.c > @@ -235,6 +235,35 @@ static void sgx_vma_close(struct vm_area_struct *vma) > kref_put(&encl->refcount, sgx_encl_release); > } > > +int sgx_map_allowed(struct sgx_encl *encl, unsigned long start, > + unsigned long end, unsigned long prot) Documentation missing. > +{ > + struct sgx_encl_page *page; > + unsigned long addr; > + > + prot &= (VM_READ | VM_WRITE | VM_EXEC); > + if (!prot || !encl) > + return 0; > + > + mutex_lock(&encl->lock); > + > + for (addr = start; addr < end; addr += PAGE_SIZE) { > + page = radix_tree_lookup(&encl->page_tree, addr >> PAGE_SHIFT); > + if (!page) > + return -EACCES; > + } > + > + mutex_unlock(&encl->lock); > + > + return 0; > +} > + > +static int sgx_vma_mprotect(struct vm_area_struct *vma, unsigned long start, > + unsigned long end, unsigned long prot) > +{ > + return sgx_map_allowed(vma->vm_private_data, start, end, prot); > +} > + > static unsigned int sgx_vma_fault(struct vm_fault *vmf) > { > unsigned long addr = (unsigned long)vmf->address; > @@ -372,6 +401,7 @@ static int sgx_vma_access(struct vm_area_struct *vma, unsigned long addr, > const struct vm_operations_struct sgx_vm_ops = { > .close = sgx_vma_close, > .open = sgx_vma_open, > + .mprotect = sgx_vma_mprotect, > .fault = sgx_vma_fault, > .access = sgx_vma_access, > }; > diff --git a/arch/x86/kernel/cpu/sgx/encl.h b/arch/x86/kernel/cpu/sgx/encl.h > index c557f0374d74..6e310e3b3fff 100644 > --- a/arch/x86/kernel/cpu/sgx/encl.h > +++ b/arch/x86/kernel/cpu/sgx/encl.h > @@ -106,6 +106,9 @@ static inline unsigned long sgx_pcmd_offset(pgoff_t page_index) > sizeof(struct sgx_pcmd); > } > > +int sgx_map_allowed(struct sgx_encl *encl, unsigned long start, > + unsigned long end, unsigned long prot); > + > enum sgx_encl_mm_iter { > SGX_ENCL_MM_ITER_DONE = 0, > SGX_ENCL_MM_ITER_NEXT = 1, > -- > 2.21.0 This is missing explanation why it is OK to have a mismatch between the SECINFO flags and VM_* flags. Maybe that could be explained in sgx_map_allowed() documentation. /Jarkko