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=-5.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 45601C47257 for ; Tue, 5 May 2020 15:36:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F3BD206B9 for ; Tue, 5 May 2020 15:36:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729250AbgEEPgs (ORCPT ); Tue, 5 May 2020 11:36:48 -0400 Received: from smtp-42ac.mail.infomaniak.ch ([84.16.66.172]:38885 "EHLO smtp-42ac.mail.infomaniak.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729392AbgEEPgs (ORCPT ); Tue, 5 May 2020 11:36:48 -0400 Received: from smtp-2-0001.mail.infomaniak.ch (unknown [10.5.36.108]) by smtp-3-3000.mail.infomaniak.ch (Postfix) with ESMTPS id 49GkMz6zCDzlhnlg; Tue, 5 May 2020 17:36:15 +0200 (CEST) Received: from ns3096276.ip-94-23-54.eu (unknown [94.23.54.103]) by smtp-2-0001.mail.infomaniak.ch (Postfix) with ESMTPA id 49GkMy4bmmzlvfCB; Tue, 5 May 2020 17:36:14 +0200 (CEST) Subject: Re: [PATCH v5 0/6] Add support for O_MAYEXEC To: linux-kernel@vger.kernel.org Cc: Aleksa Sarai , Alexei Starovoitov , Al Viro , Andy Lutomirski , Christian Heimes , Daniel Borkmann , Deven Bowers , Eric Chiang , Florian Weimer , James Morris , Jan Kara , Jann Horn , Jonathan Corbet , Kees Cook , Lakshmi Ramasubramanian , Matthew Garrett , Matthew Wilcox , Michael Kerrisk , =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= , Mimi Zohar , =?UTF-8?Q?Philippe_Tr=c3=a9buchet?= , Scott Shell , Sean Christopherson , Shuah Khan , Steve Dower , Steve Grubb , Thibaut Sautereau , Vincent Strubel , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org References: <20200505153156.925111-1-mic@digikod.net> From: =?UTF-8?Q?Micka=c3=abl_Sala=c3=bcn?= Message-ID: Date: Tue, 5 May 2020 17:36:14 +0200 User-Agent: MIME-Version: 1.0 In-Reply-To: <20200505153156.925111-1-mic@digikod.net> Content-Type: text/plain; charset=utf-8 Content-Language: fr Content-Transfer-Encoding: 8bit X-Antivirus: Dr.Web (R) for Unix mail servers drweb plugin ver.6.0.2.8 X-Antivirus-Code: 0x100000 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: On 05/05/2020 17:31, Mickaël Salaün wrote: > Hi, > > This fifth patch series add new kernel configurations (OMAYEXEC_STATIC, > OMAYEXEC_ENFORCE_MOUNT, and OMAYEXEC_ENFORCE_FILE) to enable to > configure the security policy at kernel build time. As requested by > Mimi Zohar, I completed the series with one of her patches for IMA. > > The goal of this patch series is to enable to control script execution > with interpreters help. A new O_MAYEXEC flag, usable through > openat2(2), is added to enable userspace script interpreter to delegate > to the kernel (and thus the system security policy) the permission to > interpret/execute scripts or other files containing what can be seen as > commands. > > A simple system-wide security policy can be enforced by the system > administrator through a sysctl configuration consistent with the mount > points or the file access rights. The documentation patch explains the > prerequisites. > > Furthermore, the security policy can also be delegated to an LSM, either > a MAC system or an integrity system. For instance, the new kernel > MAY_OPENEXEC flag closes a major IMA measurement/appraisal interpreter > integrity gap by bringing the ability to check the use of scripts [1]. > Other uses are expected, such as for openat2(2) [2], SGX integration > [3], bpffs [4] or IPE [5]. > > Userspace needs to adapt to take advantage of this new feature. For > example, the PEP 578 [6] (Runtime Audit Hooks) enables Python 3.8 to be > extended with policy enforcement points related to code interpretation, > which can be used to align with the PowerShell audit features. > Additional Python security improvements (e.g. a limited interpreter > withou -c, stdin piping of code) are on their way. > > The initial idea come from CLIP OS 4 and the original implementation has > been used for more than 12 years: > https://github.com/clipos-archive/clipos4_doc > > An introduction to O_MAYEXEC was given at the Linux Security Summit > Europe 2018 - Linux Kernel Security Contributions by ANSSI: > https://www.youtube.com/watch?v=chNjCRtPKQY&t=17m15s > The "write xor execute" principle was explained at Kernel Recipes 2018 - > CLIP OS: a defense-in-depth OS: > https://www.youtube.com/watch?v=PjRE0uBtkHU&t=11m14s > > This patch series can be applied on top of v5.7-rc4. This can be tested > with CONFIG_SYSCTL. I would really appreciate constructive comments on > this patch series. > > Previous version: > https://lore.kernel.org/lkml/20200428175129.634352-1-mic@digikod.net/ The previous version (v4) is https://lore.kernel.org/lkml/20200430132320.699508-1-mic@digikod.net/