From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752637AbdLLP5B (ORCPT ); Tue, 12 Dec 2017 10:57:01 -0500 Received: from mail.kernel.org ([198.145.29.99]:44574 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751554AbdLLP4y (ORCPT ); Tue, 12 Dec 2017 10:56:54 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9FE49218D8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org From: Andy Lutomirski To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Borislav Petkov , Brian Gerst , David Laight , Kees Cook , Peter Zijlstra , Andy Lutomirski Subject: [PATCH PTI v3 06/10] x86/vsyscall/64: Warn and fail vsyscall emulation in NATIVE mode Date: Tue, 12 Dec 2017 07:56:41 -0800 Message-Id: X-Mailer: git-send-email 2.13.6 In-Reply-To: <24c898b4f44fdf8c22d93703850fb384ef87cfdc.1513035461.git.luto@kernel.org> References: <24c898b4f44fdf8c22d93703850fb384ef87cfdc.1513035461.git.luto@kernel.org> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If something goes wrong with pagetable setup, vsyscall=native will accidentally fall back to emulation. Make it warn and fail so that we notice. Signed-off-by: Andy Lutomirski --- arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c index bc88a0540347..a06f2ae09ad6 100644 --- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -138,6 +138,10 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) WARN_ON_ONCE(address != regs->ip); + /* This should be unreachable in NATIVE mode. */ + if (WARN_ON(vsyscall_mode == NATIVE)) + return false; + if (vsyscall_mode == NONE) { warn_bad_vsyscall(KERN_INFO, regs, "vsyscall attempted with vsyscall=none"); -- 2.13.6