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=1.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,MAILING_LIST_MULTI,SPF_PASS, USER_AGENT_MUTT 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 0FE8FC43219 for ; Fri, 26 Apr 2019 09:58:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D449F2084F for ; Fri, 26 Apr 2019 09:58:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1556272707; bh=RY7deLFuQ2+MXOQ+UyRqt5TEtBMVYn3waYXdiSMSnN4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=PXuG85I7SHz77ItN1UbaDRs92GVW6RzYb/HjrTG6OuKWwMao32FtLBPOM60kaRBTU +by4U81j1hbc5lGjAL34DLlFUtRo2eWlq/mDtyu8gkjCQ38PIg9mFWYBHC//I60CMC tQC7do3gW5kDVgBjse1O64MOX+2aKB0gV9s11dOI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726247AbfDZJ6H (ORCPT ); Fri, 26 Apr 2019 05:58:07 -0400 Received: from mail-wm1-f68.google.com ([209.85.128.68]:53538 "EHLO mail-wm1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725901AbfDZJ6H (ORCPT ); Fri, 26 Apr 2019 05:58:07 -0400 Received: by mail-wm1-f68.google.com with SMTP id 26so3066686wmj.3; Fri, 26 Apr 2019 02:58:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=YJCStWT0dNYPW3ntuISaTY+7m2TzWui5U3rbJsecnt4=; b=K85URiHSmAJ1R+AeUwGYyucXzeBGpSgFJxfInaFSv6ntKK/zvtuQaZaAHMqosXdqCQ PSwdwnK8AfCbRsW/xqF3cWnqK+cd8FYKwm1lw4QCJH13elJblsFe8d0B4rJmiaypHx2V BPKTRORhHEpvy4fMFoXLQACGi5sY1E9IPfW7Gus8e0NvyirHI1shKtQemU1+usuMcDvY yN+f5fiDh8kXry7A7CVvtVKcIK+17pib8MkhZzdPsM+nfv/EpYuyK3O/gTwUr/EbM0oj VIpstDsdgthviqEU9Rm/RpgvIMDfui0KeJJYGLxqA7m8pSj8BmzEJj7hUPmI0hkzSEgV 0w/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=YJCStWT0dNYPW3ntuISaTY+7m2TzWui5U3rbJsecnt4=; b=P0G4Bbxo3ompvRS5A5SGaJpDh9G6UQQC4m0Kn5MIkK0lecGtTDCWI5XgKcPviNqPlF WpdlGMY3OSYog/weJWOicxMd5BN0A0keXJWnnz9+x3sskMbB3FqktvRrJq9jT4FEMrKZ 2+0t3Epnh1BK6P4wRdZKXMRLhnmvgVgAaI6qnvO+W9+obAPGUPcyFVx577RC/Q8Vsl0g HH6fozK8GuFnccppPf/8Gq4LiZ20PIjo+hemnTVmAvRSPQz/Iilp4cUgejqp/ROcKbpu nqEWv4vJyJimoCPwgts7wnKf2VDYHWaKWa0IJtRmluvHXcV02K+b8WHYw2weHx80cvDp D+7Q== X-Gm-Message-State: APjAAAXrQPxqRwRs7KDpW7SaNg8oabjxbbiufdKgVFlLfoQBG0H4bknA xnvHWTmtdG48C+V/9nlBc10= X-Google-Smtp-Source: APXvYqxU4xRSO//2LeLOAQNJAxp8x2iYJV7YGaHBJl6zzDXEGkhWiOOILZ/XwIJJg56oj/prXk8sRw== X-Received: by 2002:a1c:f204:: with SMTP id s4mr7232803wmc.51.1556272685405; Fri, 26 Apr 2019 02:58:05 -0700 (PDT) Received: from gmail.com (2E8B0CD5.catv.pool.telekom.hu. [46.139.12.213]) by smtp.gmail.com with ESMTPSA id 4sm20102389wmg.12.2019.04.26.02.58.03 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 26 Apr 2019 02:58:04 -0700 (PDT) Date: Fri, 26 Apr 2019 11:58:02 +0200 From: Ingo Molnar To: Mike Rapoport Cc: linux-kernel@vger.kernel.org, Alexandre Chartre , Andy Lutomirski , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Ingo Molnar , James Bottomley , Jonathan Adams , Kees Cook , Paul Turner , Peter Zijlstra , Thomas Gleixner , linux-mm@kvack.org, linux-security-module@vger.kernel.org, x86@kernel.org, Linus Torvalds , Peter Zijlstra , Andrew Morton Subject: Re: [RFC PATCH 2/7] x86/sci: add core implementation for system call isolation Message-ID: <20190426095802.GA35515@gmail.com> References: <1556228754-12996-1-git-send-email-rppt@linux.ibm.com> <1556228754-12996-3-git-send-email-rppt@linux.ibm.com> <20190426083144.GA126896@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190426083144.GA126896@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: * Ingo Molnar wrote: > I really don't like it where this is going. In a couple of years I > really want to be able to think of PTI as a bad dream that is mostly > over fortunately. > > I have the feeling that compiler level protection that avoids > corrupting the stack in the first place is going to be lower overhead, > and would work in a much broader range of environments. Do we have > analysis of what the compiler would have to do to prevent most ROP > attacks, and what the runtime cost of that is? > > I mean, C# and Java programs aren't able to corrupt the stack as long > as the language runtime is corect. Has to be possible, right? So if such security feature is offered then I'm afraid distros would be strongly inclined to enable it - saying 'yes' to a kernel feature that can keep your product off CVE advisories is a strong force. To phrase the argument in a bit more controversial form: If the price of Linux using an insecure C runtime is to slow down system calls with immense PTI-alike runtime costs, then wouldn't it be the right technical decision to write the kernel in a language runtime that doesn't allow stack overflows and such? I.e. if having Linux in C ends up being slower than having it in Java, then what's the performance argument in favor of using C to begin with? ;-) And no, I'm not arguing for Java or C#, but I am arguing for a saner version of C. Thanks, Ingo