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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 3BDCFC2D0C6 for ; Fri, 27 Dec 2019 16:34:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 07434208C4 for ; Fri, 27 Dec 2019 16:34:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577464457; bh=/ce2ChLDw0QLOYk5XALfZjodb4g3teQx58NEvyAvA88=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rOCnee4CWxnDtUCKo0Bc3WFaeUOnfrMgUuFajgugmhcd2FFrjaL1KqOboRrS37BUi XBdwlhMKLP/+A7cdWg9qyXICmB7ZKWXzA74pmEG5rcphou9Ovpj0MeJ0Edg+1nOTnx zhZjnwFMGsgmuk18VmwAmug5BlPKW/+YdxlxCw7w= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726602AbfL0QeQ (ORCPT ); Fri, 27 Dec 2019 11:34:16 -0500 Received: from mail.kernel.org ([198.145.29.99]:46562 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726379AbfL0QeQ (ORCPT ); Fri, 27 Dec 2019 11:34:16 -0500 Received: from e123331-lin.home (amontpellier-657-1-18-247.w109-210.abo.wanadoo.fr [109.210.65.247]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4B69A2173E; Fri, 27 Dec 2019 16:34:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1577464455; bh=/ce2ChLDw0QLOYk5XALfZjodb4g3teQx58NEvyAvA88=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cn7oT7Fv+pSN16jfqC2ChE2cGsRJpggMf8O5vSCs6LVtg89SmB/vEF3uTPeK9cvpg DBgHc6nTBeJBTa52W48Kr+oflyEjUHr3XFkZdqX6n49WxOOX3HG9r0J613EYTLzyGf vZ/J/u70f9YW1XN1Jtx+fnIkxyX27MiPVMIpR+zI= From: Ard Biesheuvel To: linux-efi@vger.kernel.org Cc: nivedita@alum.mit.edu, hdegoede@redhat.com, Ard Biesheuvel , Andy Lutomirski , Ingo Molnar Subject: [PATCH 1/3] x86/mm: fix NX bit clearing issue in kernel_map_pages_in_pgd Date: Fri, 27 Dec 2019 17:34:16 +0100 Message-Id: <20191227163418.16139-2-ardb@kernel.org> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191227163418.16139-1-ardb@kernel.org> References: <20191227163418.16139-1-ardb@kernel.org> Sender: linux-efi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Commit 15f003d20782 ("x86/mm/pat: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd()") modified kernel_map_pages_in_pgd() to manage writable permissions of memory mappings in the EFI page table in a different way, but in the process, it removed the ability to clear NX attributes from read-only mappings, by clobbering the clear mask if _PAGE_RW is not being requested. Failure to remove the NX attribute from read-only mappings is unlikely to be a security issue, but it does prevent us from tightening the permissions in the EFI page tables going forward, so let's fix it now. Fixes: 15f003d20782 ("x86/mm/pat: Don't implicitly allow _PAGE_RW in kernel_map_pages_in_pgd() Signed-off-by: Ard Biesheuvel --- arch/x86/mm/pageattr.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 1b99ad05b117..f42780ba0893 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -2215,7 +2215,7 @@ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, .pgd = pgd, .numpages = numpages, .mask_set = __pgprot(0), - .mask_clr = __pgprot(0), + .mask_clr = __pgprot(~page_flags & (_PAGE_NX|_PAGE_RW)), .flags = 0, }; @@ -2224,12 +2224,6 @@ int __init kernel_map_pages_in_pgd(pgd_t *pgd, u64 pfn, unsigned long address, if (!(__supported_pte_mask & _PAGE_NX)) goto out; - if (!(page_flags & _PAGE_NX)) - cpa.mask_clr = __pgprot(_PAGE_NX); - - if (!(page_flags & _PAGE_RW)) - cpa.mask_clr = __pgprot(_PAGE_RW); - if (!(page_flags & _PAGE_ENC)) cpa.mask_clr = pgprot_encrypted(cpa.mask_clr); -- 2.17.1