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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 8B6F3C4727D for ; Sat, 3 Oct 2020 04:51:31 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E76DC221E5 for ; Sat, 3 Oct 2020 04:51:30 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E76DC221E5 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0BD7D6B005C; Sat, 3 Oct 2020 00:51:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 045166B005D; Sat, 3 Oct 2020 00:51:29 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E4EFE6B0062; Sat, 3 Oct 2020 00:51:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0125.hostedemail.com [216.40.44.125]) by kanga.kvack.org (Postfix) with ESMTP id B41DD6B005C for ; Sat, 3 Oct 2020 00:51:29 -0400 (EDT) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 26B818249980 for ; Sat, 3 Oct 2020 04:51:29 +0000 (UTC) X-FDA: 77329390698.29.fan20_3403732271aa Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin29.hostedemail.com (Postfix) with ESMTP id 0CDAB18085CFA for ; Sat, 3 Oct 2020 04:51:29 +0000 (UTC) X-HE-Tag: fan20_3403732271aa X-Filterd-Recvd-Size: 5186 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf23.hostedemail.com (Postfix) with ESMTP for ; Sat, 3 Oct 2020 04:51:28 +0000 (UTC) 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 8B4F9221EA; Sat, 3 Oct 2020 04:51:26 +0000 (UTC) From: Jarkko Sakkinen To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Sean Christopherson , linux-mm@kvack.org, Andrew Morton , Matthew Wilcox , Jethro Beekman , Darren Kenny , Jarkko Sakkinen , 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, tglx@linutronix.de, yaozhangx@google.com, mikko.ylinen@intel.com Subject: [PATCH v39 10/24] mm: Add 'mprotect' hook to struct vm_operations_struct Date: Sat, 3 Oct 2020 07:50:45 +0300 Message-Id: <20201003045059.665934-11-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 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Sean Christopherson Background =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D 1. SGX enclave pages are populated with data by copying data to them from normal memory via an ioctl() (SGX_IOC_ENCLAVE_ADD_PAGES). 2. It is desirable to be able to restrict those normal memory data source= s. For instance, to ensure that the source data is executable before copying data to an executable enclave page. 3. Enclave page permissions are dynamic (just like normal permissions) an= d can be adjusted at runtime with mprotect(). 4. The original data source may have long since vanished at the time when enclave page permissions are established (mmap() or mprotect()). The solution (elsewhere in this series) is to force enclaves creators to declare their paging permission *intent* up front to the ioctl(). This intent can me immediately compared to the source data=E2=80=99s mapping (= and rejected if necessary). The intent is also stashed off for later comparison with enclave PTEs. This ensures that any future mmap()/mprotect() operations performed by th= e enclave creator or done on behalf of the enclave can be compared with the earlier declared permissions. Problem =3D=3D=3D=3D=3D=3D=3D There is an existing mmap() hook which allows SGX to perform this permission comparison at mmap() time. However, there is no corresponding ->mprotect() hook. Solution =3D=3D=3D=3D=3D=3D=3D=3D Add a vm_ops->mprotect() hook so that mprotect() operations which are inconsistent with any page's stashed intent can be rejected by the driver= . Cc: linux-mm@kvack.org Cc: Andrew Morton Cc: Matthew Wilcox Acked-by: Jethro Beekman Reviewed-by: Darren Kenny Signed-off-by: Sean Christopherson Co-developed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- include/linux/mm.h | 3 +++ mm/mprotect.c | 5 ++++- 2 files changed, 7 insertions(+), 1 deletion(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index b2f370f0b420..dca57fe80555 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -551,6 +551,9 @@ struct vm_operations_struct { void (*close)(struct vm_area_struct * area); int (*split)(struct vm_area_struct * area, unsigned long addr); int (*mremap)(struct vm_area_struct * area); + int (*mprotect)(struct vm_area_struct *vma, + struct vm_area_struct **pprev, unsigned long start, + unsigned long end, unsigned long newflags); vm_fault_t (*fault)(struct vm_fault *vmf); vm_fault_t (*huge_fault)(struct vm_fault *vmf, enum page_entry_size pe_size); diff --git a/mm/mprotect.c b/mm/mprotect.c index ce8b8a5eacbb..f170f3da8a4f 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -610,7 +610,10 @@ static int do_mprotect_pkey(unsigned long start, siz= e_t len, tmp =3D vma->vm_end; if (tmp > end) tmp =3D end; - error =3D mprotect_fixup(vma, &prev, nstart, tmp, newflags); + if (vma->vm_ops && vma->vm_ops->mprotect) + error =3D vma->vm_ops->mprotect(vma, &prev, nstart, tmp, newflags); + else + error =3D mprotect_fixup(vma, &prev, nstart, tmp, newflags); if (error) goto out; nstart =3D tmp; --=20 2.25.1