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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 7A310C28CC6 for ; Tue, 4 Jun 2019 11:50:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5E25624865 for ; Tue, 4 Jun 2019 11:50:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727591AbfFDLuA (ORCPT ); Tue, 4 Jun 2019 07:50:00 -0400 Received: from mga01.intel.com ([192.55.52.88]:6646 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727301AbfFDLuA (ORCPT ); Tue, 4 Jun 2019 07:50:00 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Jun 2019 04:49:59 -0700 X-ExtLoop1: 1 Received: from jsakkine-mobl1.tm.intel.com (HELO localhost) ([10.237.50.189]) by fmsmga008.fm.intel.com with ESMTP; 04 Jun 2019 04:49:51 -0700 Date: Tue, 4 Jun 2019 14:49:51 +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 2/9] x86/sgx: Do not naturally align MAP_FIXED address Message-ID: <20190604114951.GC30594@linux.intel.com> References: <20190531233159.30992-1-sean.j.christopherson@intel.com> <20190531233159.30992-3-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190531233159.30992-3-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: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org On Fri, May 31, 2019 at 04:31:52PM -0700, Sean Christopherson wrote: > SGX enclaves have an associated Enclave Linear Range (ELRANGE) that is > tracked and enforced by the CPU using a base+mask approach, similar to > how hardware range registers such as the variable MTRRs. As a result, > the ELRANGE must be naturally sized and aligned. > > To reduce boilerplate code that would be needed in every userspace > enclave loader, the SGX driver naturally aligns the mmap() address and > also requires the range to be naturally sized. Unfortunately, SGX fails > to grant a waiver to the MAP_FIXED case, e.g. incorrectly rejects mmap() > if userspace is attempting to map a small slice of an existing enclave. > > Signed-off-by: Sean Christopherson Why you want to allow mmap() to be called multiple times? mmap() could be allowed only once with PROT_NONE and denied afterwards. Is this for sending fd to another process that would map already existing enclave? I don't see any checks for whether the is enclave underneath. Also, I think that in all cases mmap() callback should allow only PROT_NONE as permissions for clarity even if it could called multiple times. /Jarkko