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=-13.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=no 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 24C7CC433ED for ; Wed, 7 Apr 2021 22:05:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E64646124C for ; Wed, 7 Apr 2021 22:05:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229752AbhDGWFL (ORCPT ); Wed, 7 Apr 2021 18:05:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229637AbhDGWFL (ORCPT ); Wed, 7 Apr 2021 18:05:11 -0400 Received: from mail-pg1-x52b.google.com (mail-pg1-x52b.google.com [IPv6:2607:f8b0:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1850DC061760 for ; Wed, 7 Apr 2021 15:05:00 -0700 (PDT) Received: by mail-pg1-x52b.google.com with SMTP id l76so14054806pga.6 for ; Wed, 07 Apr 2021 15:05:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wH47jkj5S01XtLG9mqIn/0RS8pjr8zTeS3YRDC+IerM=; b=cbvFByG+VGs0Zws3AKH8tM3Vb9ziVhXmXafsPjAdvsok4vtedKTwj6VTqONg+3OZRo 3ip6UggFgETc/hCIr551tQ2Unkb2AaAYD1ZRyn5cu0lddqZGBJC/3ON5yWKKKK0cexcT RPEf/LOPjMKF9S8wk7HfkG5TK7+ul9HD6sZQ3w9gz7NhtOmZsA6sIt2qSZzTK04HiCI0 XKGAM2yZ1LQKr/sE22SmXC8pjPqLQ+IwlM+bMM3QNRS7fDAdFbzSCPJnpG4JW6ZZDiac gBnzoorjNRQ6ydD4B1vBlASwBM4NwJDsuPkTilvdrbnQ67UdzzIhuJyhXmWskcchY5Lk Vr7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wH47jkj5S01XtLG9mqIn/0RS8pjr8zTeS3YRDC+IerM=; b=Zo4+efE1Z3Dl1rW6YFS/1Ggv7YfHTf+xZ+Cw3HS2J1XKFGkS+0ofPdSTBenH7TNh4A /xb3oHNuefjL7cK/cJZ53rNy3GghqAcMBaktG8icOVTni0FEpI2qONMhi1QDua3kpDIk MUpLEMsTTQLbcd/KzAjshvRIEV+ZYGtaAMSdfzj5Q/FaCltrLNlupP6rOeAPVy2Y3bfI jIV9aAqHvXxc49OmpWM9PXEMRZFuPnPhqosFCFi7ea9Z9lmdC1XepCnMsKc+qtJOwcbw sXhazWlmUsZPtq0e4zGKFX8twnUxPoQWMBUjFN4BrCGRAX9q8sKOCJp9D6Blvwd/zK10 7skw== X-Gm-Message-State: AOAM533h5AkvGZRgjdKIUEUR6XfhPecNwrXG3jANWZjTobAIiIv/rZ2I nSslja2x4Kcmq5+OmInnkUoTAg== X-Google-Smtp-Source: ABdhPJycw3Ip2ZYVbU5IdBWfM80vuSAGI32jxVnYO6j0W1f8udMokCjUCNVmtxIH6B7uvRZzyXbT9g== X-Received: by 2002:a62:7f02:0:b029:244:152b:99a5 with SMTP id a2-20020a627f020000b0290244152b99a5mr782397pfd.46.1617833099506; Wed, 07 Apr 2021 15:04:59 -0700 (PDT) Received: from google.com (240.111.247.35.bc.googleusercontent.com. [35.247.111.240]) by smtp.gmail.com with ESMTPSA id mu6sm6056208pjb.35.2021.04.07.15.04.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Apr 2021 15:04:58 -0700 (PDT) Date: Wed, 7 Apr 2021 22:04:55 +0000 From: Sean Christopherson To: Kai Huang Cc: kvm@vger.kernel.org, linux-sgx@vger.kernel.org, pbonzini@redhat.com, bp@alien8.de, jarkko@kernel.org, dave.hansen@intel.com, luto@kernel.org, rick.p.edgecombe@intel.com, haitao.huang@intel.com Subject: Re: [PATCH v4 07/11] KVM: VMX: Add SGX ENCLS[ECREATE] handler to enforce CPUID restrictions Message-ID: References: <963a2416333290e23773260d824a9e038aed5a53.1617825858.git.kai.huang@intel.com> <20210408095822.24d0c709c2680bb78b689ed1@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210408095822.24d0c709c2680bb78b689ed1@intel.com> Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Thu, Apr 08, 2021, Kai Huang wrote: > On Wed, 7 Apr 2021 21:52:50 +0000 Sean Christopherson wrote: > > On Thu, Apr 08, 2021, Kai Huang wrote: > > > + /* > > > + * Copy contents into kernel memory to prevent TOCTOU attack. E.g. the > > > + * guest could do ECREATE w/ SECS.SGX_ATTR_PROVISIONKEY=0, and > > > + * simultaneously set SGX_ATTR_PROVISIONKEY to bypass the check to > > > + * enforce restriction of access to the PROVISIONKEY. > > > + */ > > > + contents = (struct sgx_secs *)__get_free_page(GFP_KERNEL); > > > > This should use GFP_KERNEL_ACCOUNT. > > May I ask why? The page is only a temporary allocation, it will be freed before > this function returns. I guess a 4K page is OK? A hard limit should not be violated, even temporarily. This is also per vCPU, e.g. a 256 vCPU VM could go 1mb over the limit.