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=-2.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 5F3D6C31E40 for ; Tue, 6 Aug 2019 15:44:07 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id A904C20C01 for ; Tue, 6 Aug 2019 15:44:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="dt2cjv9c" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A904C20C01 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=alien8.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-16726-kernel-hardening=archiver.kernel.org@lists.openwall.com Received: (qmail 19818 invoked by uid 550); 6 Aug 2019 15:44:00 -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 19793 invoked from network); 6 Aug 2019 15:43:59 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1565106228; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=TDFDazt6//hwNfwRMzmVKFiu4ldxLz+yMwXDE8Lj5Eo=; b=dt2cjv9ck6Riog7ad+ewdarAX2dM8UrmZhk8qdfxpW8EfZWGjwleuVrU4g1cmXqrcn8Kh+ TWcpA8A1qy+/qbzkXNRCP6wNTc/+TBGiGV3muxnmmGbdGi77lel3IPkl79O3Iqqfn0x3XN 2iqBRrkAzDyyrAqpiKzGnDMqxESTm0c= Date: Tue, 6 Aug 2019 17:43:47 +0200 From: Borislav Petkov To: Thomas Garnier Cc: kernel-hardening@lists.openwall.com, kristen@linux.intel.com, keescook@chromium.org, Herbert Xu , "David S. Miller" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, Andy Lutomirski , Juergen Gross , Thomas Hellstrom , "VMware, Inc." , "Rafael J. Wysocki" , Len Brown , Pavel Machek , Peter Zijlstra , Nadav Amit , Jann Horn , Feng Tang , Maran Wilson , Enrico Weigelt , Allison Randal , Alexios Zavras , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, linux-pm@vger.kernel.org Subject: Re: [PATCH v9 00/11] x86: PIE support to extend KASLR randomization Message-ID: <20190806154347.GD25897@zn.tnic> References: <20190730191303.206365-1-thgarnie@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190730191303.206365-1-thgarnie@chromium.org> User-Agent: Mutt/1.10.1 (2018-07-13) On Tue, Jul 30, 2019 at 12:12:44PM -0700, Thomas Garnier wrote: > These patches make some of the changes necessary to build the kernel as > Position Independent Executable (PIE) on x86_64. Another patchset will > add the PIE option and larger architecture changes. Yeah, about this: do we have a longer writeup about the actual benefits of all this and why we should take this all? After all, after looking at the first couple of asm patches, it is posing restrictions to how we deal with virtual addresses in asm (only RIP-relative addressing in 64-bit mode, MOVs with 64-bit immediates, etc, for example) and I'm willing to bet money that some future unrelated change will break PIE sooner or later. And I'd like to have a better justification why we should enforce those new "rules" unconditionally. Thx. -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.