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=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 BE15AC48BD7 for ; Thu, 27 Jun 2019 17:30:22 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 1E1CF2133F for ; Thu, 27 Jun 2019 17:30:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="gIwVdMW2" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E1CF2133F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=chromium.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-16305-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 32068 invoked by uid 550); 27 Jun 2019 17:30:15 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Received: (qmail 32047 invoked from network); 27 Jun 2019 17:30:14 -0000 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=BK8EGpkSg4lo/2wbZ5MoRN9FK7m59+KFamX/WJ/qAIKHG6EWViTJueU7AormfEPpA1 NROi/aXFNpQwkYwKYgVuGZzApdIbnbz6SRzBVk0+UgGO8nlMGoOjvaIn+vG2qidB0LMQ IuvxQsjnPV4sJy7G1QZqcXqXE7yyX/Om/K+Vf2XGCTF2e4zBYi2tKwqSuX21awfuHA2n 76vR4ZWdLfkDZnzIDGpUUgBcHxNoc6WXijPEwqFDVEN1B3ZH/bwprzwXTBuwSQnz5r59 72h9jVtWFKPAw5HXlm/HQPxIwm9ZHHddksiFbYonMSRxfzK7NUPvQxhn1e780rkdKBgl TcJw== X-Gm-Message-State: APjAAAVNXQLnBadvAoonpiM2yiRFBoTn6Qzn1d5VVNtf1F/HGK9VsdqN c2QKtQOa0tToUr30W2qeGvQsPQ== 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) 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> 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