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=-1.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A03CCC4360C for ; Sat, 12 Oct 2019 23:13:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6948E206A1 for ; Sat, 12 Oct 2019 23:13:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570922010; bh=+wHs2Y/Qg5mogbSpED8FXiNC/fGFHyhQ+Ml3FmkKkSo=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=HD32SQhnMfviVPly/m9w7glaezizfirmowX4Rt6ZEvC/+75AdYSc51LscpBxV7tzs ywr4Cdl47BreEDpEIm2UnQqwpoBMwgP7hLq0AC62zT8U0jWRCzv3jxFLfjFWoq7zcm jAL59FBs6dAEBsAxYB/SfOx9ZrPdi4cEZFsOZZb8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728090AbfJLXND (ORCPT ); Sat, 12 Oct 2019 19:13:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:49372 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727149AbfJLXNC (ORCPT ); Sat, 12 Oct 2019 19:13:02 -0400 Received: from mail-wr1-f48.google.com (mail-wr1-f48.google.com [209.85.221.48]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 167A02089F for ; Sat, 12 Oct 2019 23:13:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570921982; bh=+wHs2Y/Qg5mogbSpED8FXiNC/fGFHyhQ+Ml3FmkKkSo=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=WwC2Zd/EElIEXkBTdXusEwwsN4TJ4e5D5MZxTtfywIxcnPXQrwGl5L6KJELMbxZCM S2pRWM8koBpwKPoErCqpDh/JoZER3vtzcv1N90m4xpbH+WN/fw1KTsMGpT5lRl4XwD HHBuNFJU67xnwaOi7vgnJujwYccyolwUM8aW4WPE= Received: by mail-wr1-f48.google.com with SMTP id j11so15578621wrp.1 for ; Sat, 12 Oct 2019 16:13:02 -0700 (PDT) X-Gm-Message-State: APjAAAWHHOOyjjvsTTJKTXy2MJwMKsbGPFqxzHd1U3PY3U8Rxk1/ql/I Wq+eAlkYZn7lQeIc/Zqv9nTQ/2AfvBFLMnNbqXJ+cw== X-Google-Smtp-Source: APXvYqw7HEa5GYoH47kjNp12sTWsxaiCKc6Zk/2lzuijVQxR+tnPNkLDBsht+XtGjda/KjufIv6NxSXSW8gqONbWoYA= X-Received: by 2002:adf:f9cf:: with SMTP id w15mr20086297wrr.61.1570921980646; Sat, 12 Oct 2019 16:13:00 -0700 (PDT) MIME-Version: 1.0 References: <20191012191602.45649-1-dancol@google.com> <20191012191602.45649-7-dancol@google.com> In-Reply-To: <20191012191602.45649-7-dancol@google.com> From: Andy Lutomirski Date: Sat, 12 Oct 2019 16:12:49 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 6/7] Allow users to require UFFD_SECURE To: Daniel Colascione Cc: Linux API , LKML , lokeshgidra@google.com, Nick Kralevich , nosh@google.com, Tim Murray 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 Sat, Oct 12, 2019 at 12:16 PM Daniel Colascione wrote: > > This change adds 2 as an allowable value for > unprivileged_userfaultfd. (Previously, this sysctl could be either 0 > or 1.) When unprivileged_userfaultfd is 2, users with CAP_SYS_PTRACE > may create userfaultfd with or without UFFD_SECURE, but users without > CAP_SYS_PTRACE must pass UFFD_SECURE to userfaultfd in order for the > system call to succeed, effectively forcing them to opt into > additional security checks. This patch can go away entirely if you make UFFD_SECURE automatic.