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=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 01E8AC43469 for ; Fri, 18 Sep 2020 19:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C2AAD221EC for ; Fri, 18 Sep 2020 19:24:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726840AbgIRTYR (ORCPT ); Fri, 18 Sep 2020 15:24:17 -0400 Received: from mga14.intel.com ([192.55.52.115]:44701 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726811AbgIRTYP (ORCPT ); Fri, 18 Sep 2020 15:24:15 -0400 IronPort-SDR: 0QRhzVnerpejLKrcHfe5P6VW5obmHdo/P1uWx+M5KbheIsp5rOFBBMlKrq5cAa76zAu2fmRFc3 5aSWlYM6b7Nw== X-IronPort-AV: E=McAfee;i="6000,8403,9748"; a="159330654" X-IronPort-AV: E=Sophos;i="5.77,274,1596524400"; d="scan'208";a="159330654" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2020 12:23:32 -0700 IronPort-SDR: Nho7nHA5b5XpzAcHxNEw5h09TPc6KRo+anc12hycz+GZPgKxhymLdoeYO7wmK796bYz31fYQd8 QCN2mRkHYjLg== X-IronPort-AV: E=Sophos;i="5.77,274,1596524400"; d="scan'208";a="484332829" Received: from yyu32-desk.sc.intel.com ([143.183.136.146]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Sep 2020 12:23:32 -0700 From: Yu-cheng Yu To: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-api@vger.kernel.org, Arnd Bergmann , Andy Lutomirski , Balbir Singh , Borislav Petkov , Cyrill Gorcunov , Dave Hansen , Eugene Syromiatnikov , Florian Weimer , "H.J. Lu" , Jann Horn , Jonathan Corbet , Kees Cook , Mike Kravetz , Nadav Amit , Oleg Nesterov , Pavel Machek , Peter Zijlstra , Randy Dunlap , "Ravi V. Shankar" , Vedvyas Shanbhogue , Dave Martin , Weijiang Yang Cc: Yu-cheng Yu Subject: [PATCH v12 8/8] x86: Disallow vsyscall emulation when CET is enabled Date: Fri, 18 Sep 2020 12:23:12 -0700 Message-Id: <20200918192312.25978-9-yu-cheng.yu@intel.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20200918192312.25978-1-yu-cheng.yu@intel.com> References: <20200918192312.25978-1-yu-cheng.yu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org Emulation of the legacy vsyscall page is required by some programs built before 2013. Newer programs after 2013 don't use it. Disable vsyscall emulation when Control-flow Enforcement (CET) is enabled to enhance security. Signed-off-by: Yu-cheng Yu --- v12: - Disable vsyscall emulation only when it is attempted (vs. at compile time). arch/x86/entry/vsyscall/vsyscall_64.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c index 44c33103a955..3196e963e365 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -150,6 +150,15 @@ bool emulate_vsyscall(unsigned long error_code, WARN_ON_ONCE(address != regs->ip); +#ifdef CONFIG_X86_INTEL_CET + if (current->thread.cet.shstk_size || + current->thread.cet.ibt_enabled) { + warn_bad_vsyscall(KERN_INFO, regs, + "vsyscall attempted with cet enabled"); + return false; + } +#endif + if (vsyscall_mode == NONE) { warn_bad_vsyscall(KERN_INFO, regs, "vsyscall attempted with vsyscall=none"); -- 2.21.0