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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 3612EC4360F for ; Thu, 14 Mar 2019 15:23:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 073902184C for ; Thu, 14 Mar 2019 15:23:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="A04py3Qh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726898AbfCNPX2 (ORCPT ); Thu, 14 Mar 2019 11:23:28 -0400 Received: from mail-lf1-f65.google.com ([209.85.167.65]:46799 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726330AbfCNPX2 (ORCPT ); Thu, 14 Mar 2019 11:23:28 -0400 Received: by mail-lf1-f65.google.com with SMTP id a132so3085448lfa.13; Thu, 14 Mar 2019 08:23:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=5TO12yM7WufkWFhciODab08c+uIiLHgK9xAYUtoPnjg=; b=A04py3QhidUEtRAHxPxTRn/F0L8fiHLfTcI3ptvIahJ4eXSUgKDbbwXsW91oGBQsfF S08CxrQDGCZasd03tij9Z3xNLDPJq3NpBSbEXuXr1bOTloe1Vfr1F/N8GNB1ZztJFcI6 2Jwv7i5eR5SHT7+T2ToYx6LSfA7+20TDZL1usrloJSIhi/tkSKCN4uRmDIN7XWyxwn4F GrKafH9Ov6adDQ5sqRFjDIyx2w4EJ+eRFiSXwoeJi+yy7x0UgHF6UNGuR3Xf4AUNYOed 2e0b982fIq3+EdGb3RynlzXo5hqDeuWVdGBZWVXhdZZsz8Y+Nin+76LA+ON3wpr1kHDi 8D0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=5TO12yM7WufkWFhciODab08c+uIiLHgK9xAYUtoPnjg=; b=mZyqy/tOIr8rpEbesk9OqUS5E8PsAU8OcPDki7aZaZVvajgl6+c0oPIF0IkXanmYxq lXDUxCIoVNPau3G5nRC6jr/Wn+wk3T9fjz5NzAIuMXIvj2UtQi+cHg6jOSIVTqYy/3vO EWDhjjyeEUefl6lu/B4g2nXW1xQODaSySFuCxkhGPzVy0OxF5q/almz85svJjxc0GOFH 6eSmnvVBsff7DRg5yV5RPETcIMFsx4QSJL0ryuYd6YiCKnL3w4qjKto/6lHxo2gPMNej nu6vUUyjiREy79S6v0I1HT7rAPu5FGdTP/k2GUsAg2cbYQ4+UWeTYBvhnMb/Od2Qu6xa Wl+g== X-Gm-Message-State: APjAAAXF8fcrB1maibkz+PhCtLi+NiSdVUaWp7NRpBvsNol6lpgQobLe 0jA/4+ybSH/WCkGZvkD6/56KW76kQmaLOw3FXd8= X-Google-Smtp-Source: APXvYqzRC8LBbbd9Z4o3g/WcEnkmCwELLtyDuivnnwdj+alwtyYDSvB1rYiuEwroOTFRphbRB16BnPKtUiqnNqtLyWU= X-Received: by 2002:ac2:4343:: with SMTP id o3mr8059614lfl.129.1552577005440; Thu, 14 Mar 2019 08:23:25 -0700 (PDT) MIME-Version: 1.0 References: <20190311093701.15734-1-peterx@redhat.com> <58e63635-fc1b-cb53-a4d1-237e6b8b7236@oracle.com> <20190313060023.GD2433@xz-x1> <3714d120-64e3-702e-6eef-4ef253bdb66d@redhat.com> <20190313185230.GH25147@redhat.com> <1934896481.7779933.1552504348591.JavaMail.zimbra@redhat.com> <20190313234458.GJ25147@redhat.com> <298b9469-abd2-b02b-5c71-529b8976a46c@redhat.com> In-Reply-To: <298b9469-abd2-b02b-5c71-529b8976a46c@redhat.com> From: Alexei Starovoitov Date: Thu, 14 Mar 2019 08:23:13 -0700 Message-ID: Subject: Re: [PATCH 0/3] userfaultfd: allow to forbid unprivileged users To: Paolo Bonzini Cc: Andrea Arcangeli , Peter Xu , Mike Kravetz , LKML , Hugh Dickins , Luis Chamberlain , Maxime Coquelin , kvm@vger.kernel.org, Jerome Glisse , Pavel Emelyanov , Johannes Weiner , Martin Cracauer , Denis Plotnikov , linux-mm , Marty McFadden , Maya Gokhale , Mike Rapoport , Kees Cook , Mel Gorman , "Kirill A . Shutemov" , Linux-Fsdevel , "Dr . David Alan Gilbert" , Andrew Morton , Daniel Borkmann Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 14, 2019 at 4:00 AM Paolo Bonzini wrote: > > On 14/03/19 00:44, Andrea Arcangeli wrote: > > Then I thought we can add a tristate so an open of /dev/kvm would also > > allow the syscall to make things more user friendly because > > unprivileged containers ideally should have writable mounts done with > > nodev and no matter the privilege they shouldn't ever get an hold on > > the KVM driver (and those who do, like kubevirt, will then just work). > > I wouldn't even bother with the KVM special case. Containers can use > seccomp if they want a fine-grained policy. > > (Actually I wouldn't bother with the knob at all; the attack surface of > userfaultfd is infinitesimal compared to the BPF JIT...). please name _one_ BPF JIT bug that affected unprivileged user space.