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=-11.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT,USER_IN_DEF_DKIM_WL 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 48224C43331 for ; Thu, 26 Mar 2020 18:15:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1856420719 for ; Thu, 26 Mar 2020 18:15:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="L4H51g1y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727611AbgCZSPM (ORCPT ); Thu, 26 Mar 2020 14:15:12 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:48452 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727354AbgCZSPM (ORCPT ); Thu, 26 Mar 2020 14:15:12 -0400 Received: by mail-qt1-f201.google.com with SMTP id n89so5835970qte.15 for ; Thu, 26 Mar 2020 11:15:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=9W2imRwNIX90Y+pv7hvZUio45RVHKjTkCMpOp3XQz5g=; b=L4H51g1ye0QBy1pKesN7K+qpxcMZHaR/pvy4tsx/SOQ791OkKaMGWDK8acZTk9VIvo 79JW3+veC4INQH6pDPz3HMLI5aMFnzztdMR7KcXsOg2upVPHvZ5+/9NY9d99M9AwsHxr 0HywX1EfJOf+TjX+zojuN3zm1Rq0DcTyRlJCyG9OMVaQwX1VwLwOH89FeCWjtk0CaNY9 DxCYvgfbdWT2LSpz7hnG+2EE6W3BuqfCdVvxI2Qj0jh6oObj8Zd456/UGglmhP8oo3pF IpTY/tcb2l+BkqjcDQeaamxI4lbEhzTiRJJtuLRYW4vTY8iTvatwecihnymCxzMYIDbS hvfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=9W2imRwNIX90Y+pv7hvZUio45RVHKjTkCMpOp3XQz5g=; b=n4DlcSfwNrG7UtUNzg4HZvWSfxEm8qgjMR+LY0eGE30yhP5XSQLz+RR9Pcy0mdz8sB hiODB2hmgvAbbt04l6QfqsHzXGX9WOh375r/BNUFOrXZwPHgoC/VqIGhCozASqt0+Y2r lsFBj+Gl68pIv1XjdR184nCX4QoyxveBF5pFJqdOFOLinUeburgi+e2EcrbbStHsicc+ j5DWKvwHmgYYvUqAoS0SqXlgFXcOGtzHbSG0Olt196aSASWqbZebTurdqO4ewZjllkg9 E6T2fLlbRAkyVdF2aPXZ/32UiCWvv6JNl7eZreBdD0l74Nuzl3M9DHCNLedrfAbtN7bU VDyA== X-Gm-Message-State: ANhLgQ17pP+kh5RzUuEKQtbq7F/1+jdaQQeIIfCkELIvCb5ZVXqlfOLu QWeBGZdqzeTQ/VOrrH0/ibZ2YqxtKiU= X-Google-Smtp-Source: ADFU+vuXYWs53KZQSCzq/xUwtE1DCsUixB0nXsvXZzDLn/OQfnLie5fjL6+pvJ2MBJlcFVtiiQax9ZZZqwI= X-Received: by 2002:aed:37c3:: with SMTP id j61mr639522qtb.284.1585246510936; Thu, 26 Mar 2020 11:15:10 -0700 (PDT) Date: Thu, 26 Mar 2020 11:14:53 -0700 In-Reply-To: <20200214032635.75434-1-dancol@google.com> Message-Id: <20200326181456.132742-1-dancol@google.com> Mime-Version: 1.0 References: <20200214032635.75434-1-dancol@google.com> X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH v3 0/3] SELinux support for anonymous inodes and UFFD From: Daniel Colascione To: timmurray@google.com, selinux@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, viro@zeniv.linux.org.uk, paul@paul-moore.com, nnk@google.com, sds@tycho.nsa.gov, lokeshgidra@google.com, jmorris@namei.org Cc: Daniel Colascione Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: Userfaultfd in unprivileged contexts could be potentially very useful. We'd like to harden userfaultfd to make such unprivileged use less risky. This patch series allows SELinux to manage userfaultfd file descriptors and in the future, other kinds of anonymous-inode-based file descriptor. SELinux policy authors can apply policy types to anonymous inodes by providing name-based transition rules keyed off the anonymous inode internal name ( "[userfaultfd]" in the case of userfaultfd(2) file descriptors) and applying policy to the new SIDs thus produced. Inside the kernel, a pair of new anon_inodes interface, anon_inode_getfile_secure and anon_inode_getfd_secure, allow callers to opt into this SELinux management. In this new "secure" mode, anon_inodes creates new ephemeral inodes for anonymous file objects instead of reusing the normal anon_inodes singleton dummy inode. A new LSM hook gives security modules an opportunity to configure and veto these ephemeral inodes. This patch series is one of two fork of [1] and is an alternative to [2]. The primary difference between the two patch series is that this partch series creates a unique inode for each "secure" anonymous inode, while the other patch series ([2]) continues using the singleton dummy anonymous inode and adds a way to attach SELinux security information directly to file objects. I prefer the approach in this patch series because 1) it's a smaller patch than [2], and 2) it produces a more regular security architecture: in this patch series, secure anonymous inodes aren't S_PRIVATE and they maintain the SELinux property that the label for a file is in its inode. We do need an additional inode per anonymous file, but per-struct-file inode creation doesn't seem to be a problem for pipes and sockets. The previous version of this feature ([1]) created a new SELinux security class for userfaultfd file descriptors. This version adopts the generic transition-based approach of [2]. This patch series also differs from [2] in that it doesn't affect all anonymous inodes right away --- instead requiring anon_inodes callers to opt in --- but this difference isn't one of basic approach. The important question to resolve is whether we should be creating new inodes or enhancing per-file data. Changes from the first version of the patch: - Removed some error checks - Defined a new anon_inode SELinux class to resolve the ambiguity in [3] - Inherit sclass as well as descriptor from context inode Changes from the second version of the patch: - Fixed example policy in the commit message to reflect the use of the new anon_inode class. [1] https://lore.kernel.org/lkml/20200211225547.235083-1-dancol@google.com/ [2] https://lore.kernel.org/linux-fsdevel/20200213194157.5877-1-sds@tycho.nsa.gov/ [3] https://lore.kernel.org/lkml/23f725ca-5b5a-5938-fcc8-5bbbfc9ba9bc@tycho.nsa.gov/ Daniel Colascione (3): Add a new LSM-supporting anonymous inode interface Teach SELinux about anonymous inodes Wire UFFD up to SELinux fs/anon_inodes.c | 196 ++++++++++++++++++++++------ fs/userfaultfd.c | 30 ++++- include/linux/anon_inodes.h | 13 ++ include/linux/lsm_hooks.h | 9 ++ include/linux/security.h | 4 + security/security.c | 10 ++ security/selinux/hooks.c | 54 ++++++++ security/selinux/include/classmap.h | 2 + 8 files changed, 272 insertions(+), 46 deletions(-) -- 2.25.1.696.g5e7596f4ac-goog