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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 E7C48C48BD7 for ; Thu, 27 Jun 2019 17:30:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BF5792146E for ; Thu, 27 Jun 2019 17:30:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="gIwVdMW2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726674AbfF0RaF (ORCPT ); Thu, 27 Jun 2019 13:30:05 -0400 Received: from mail-pl1-f194.google.com ([209.85.214.194]:36996 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726487AbfF0RaD (ORCPT ); Thu, 27 Jun 2019 13:30:03 -0400 Received: by mail-pl1-f194.google.com with SMTP id bh12so1659167plb.4 for ; Thu, 27 Jun 2019 10:30:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=sqjgvA4tRI7gKXcYMCta47rMHZPYdqhreyw0ltkm5k4=; b=gIwVdMW2M0Xb8QXHac7LT85o8JUB3yXqnOVg8tPtqn6MlnaF7dsdIt9ho5MXcMFGcH vo1ZIAd2cmou7O23mzuhRtXvCTWVrEZ4GO3lvJs5z9K3wSenB4IgRxX9wSXiiXESbZ8I iQhVvuYzrb1LzX6+yTIs2/9up/lZ0BQGPLeas= 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=sqjgvA4tRI7gKXcYMCta47rMHZPYdqhreyw0ltkm5k4=; b=cVWICoskKvoFmVi3AAyBirkjMPk2by0Cpk4mZc1PF+NkDGqDfB4QxNk2qBMeJLCBC1 +C/Dzc/6sI2OBVaIBJEGCfAtNoeSkbT/ctUQZuplr8bru7PCQDtc9BSQfdK0ooNsWeDO czAuMSM8Qfg9faBI2pgIETmKbriphUfgjeFmqn0VBvel2uW32S3Dd96lxsg8SX6a7sZI Mg7IppeC6y1R/jaVfNQ07EtAEt02T2ay9/iV7oICHnsLNXmmjtzQD5XKF3bls0YcSl4U DI9lDENPupLC0a0f6GdupFCuyAKpf2IoYN4TbHt3Vj7Aw88tgpPDZx2JaOGPMUcfTMEZ 3RFw== X-Gm-Message-State: APjAAAWpg8moCNbtggEN53sDng2aJDupe510NU0NjqyihK1rEU02UNCJ Q/62J0JGl7KU28pGy5zfVBM4Qq8JQVA= X-Google-Smtp-Source: APXvYqwPcBbkreT9oXxP01E3l2iGaTwsfiGLYGLgb7tU8kShnT1MEu64YHMK+0/M//JyJa7+K31l3Q== X-Received: by 2002:a17:902:be12:: with SMTP id r18mr5657298pls.341.1561656602817; Thu, 27 Jun 2019 10:30:02 -0700 (PDT) Received: from www.outflux.net (smtp.outflux.net. [198.145.64.163]) by smtp.gmail.com with ESMTPSA id h14sm3638917pfq.22.2019.06.27.10.30.01 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 27 Jun 2019 10:30:02 -0700 (PDT) Date: Thu, 27 Jun 2019 10:30:01 -0700 From: Kees Cook To: Andy Lutomirski Cc: x86@kernel.org, LKML , Florian Weimer , Jann Horn , Borislav Petkov , Kernel Hardening , Peter Zijlstra , Thomas Gleixner Subject: Re: [PATCH v2 6/8] x86/vsyscall: Change the default vsyscall mode to xonly Message-ID: <201906271029.584EC8319@keescook> References: <30539f8072d2376b9c9efcc07e6ed0d6bf20e882.1561610354.git.luto@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <30539f8072d2376b9c9efcc07e6ed0d6bf20e882.1561610354.git.luto@kernel.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 26, 2019 at 09:45:07PM -0700, Andy Lutomirski wrote: > The use case for full emulation over xonly is very esoteric. Let's > change the default to the safer xonly mode. > > Cc: Kees Cook > Cc: Borislav Petkov > Cc: Kernel Hardening > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Signed-off-by: Andy Lutomirski I still think it'd be valuable to describe any known esoteric cases here, but regardless: Reviewed-by: Kees Cook -Kees > --- > arch/x86/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > index 0182d2c67590..32028edc1b0e 100644 > --- a/arch/x86/Kconfig > +++ b/arch/x86/Kconfig > @@ -2285,7 +2285,7 @@ config COMPAT_VDSO > choice > prompt "vsyscall table for legacy applications" > depends on X86_64 > - default LEGACY_VSYSCALL_EMULATE > + default LEGACY_VSYSCALL_XONLY > help > Legacy user code that does not know how to find the vDSO expects > to be able to issue three syscalls by calling fixed addresses in > -- > 2.21.0 > -- Kees Cook