From patchwork Wed Dec 12 08:17:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= X-Patchwork-Id: 10725659 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 67243159A for ; Wed, 12 Dec 2018 08:18:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 564E52AF73 for ; Wed, 12 Dec 2018 08:18:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4A1512AF87; Wed, 12 Dec 2018 08:18:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 0FABB2AF73 for ; Wed, 12 Dec 2018 08:17:58 +0000 (UTC) Received: (qmail 16132 invoked by uid 550); 12 Dec 2018 08:17:57 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 16098 invoked from network); 12 Dec 2018 08:17:56 -0000 From: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= To: linux-kernel@vger.kernel.org Cc: =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Al Viro , James Morris , Jonathan Corbet , Kees Cook , Matthew Garrett , Michael Kerrisk , =?utf-8?q?Micka=C3=ABl_Sala=C3=BCn?= , Mimi Zohar , =?utf-8?q?Philippe_Tr=C3=A9buchet?= , Shuah Khan , Thibaut Sautereau , Vincent Strubel , Yves-Alexis Perez , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-security-module@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [RFC PATCH v1 0/5] Add support for O_MAYEXEC Date: Wed, 12 Dec 2018 09:17:07 +0100 Message-Id: <20181212081712.32347-1-mic@digikod.net> X-Mailer: git-send-email 2.20.0.rc2 MIME-Version: 1.0 X-Antivirus: Dr.Web (R) for Unix mail servers drweb plugin ver.6.0.2.8 X-Antivirus-Code: 0x100000 X-Virus-Scanned: ClamAV using ClamSMTP Hi, The goal of this patch series is to control script interpretation. A new O_MAYEXEC flag used by sys_open() is added to enable userland script interpreter to delegate to the kernel (and thus the system security policy) the permission to interpret scripts or other files containing what can be seen as commands. The security policy is the responsibility of an LSM. A basic system-wide policy is implemented with Yama and configurable through a sysctl. The initial idea come from CLIP OS and the original implementation has been used for more than 10 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 v4.20-rc6. This can be tested with CONFIG_SECURITY_YAMA. I would really appreciate constructive comments on this RFC. Regards, Mickaël Salaün (5): fs: Add support for an O_MAYEXEC flag on sys_open() fs: Add a MAY_EXECMOUNT flag to infer the noexec mount propertie Yama: Enforces noexec mounts or file executability through O_MAYEXEC selftest/yama: Add tests for O_MAYEXEC enforcing doc: Add documentation for Yama's open_mayexec_enforce Documentation/admin-guide/LSM/Yama.rst | 41 +++ MAINTAINERS | 1 + fs/fcntl.c | 2 +- fs/namei.c | 2 + fs/open.c | 4 + include/linux/fcntl.h | 2 +- include/linux/fs.h | 4 + include/uapi/asm-generic/fcntl.h | 3 + security/yama/Kconfig | 3 +- security/yama/yama_lsm.c | 82 +++++- tools/testing/selftests/Makefile | 1 + tools/testing/selftests/yama/.gitignore | 1 + tools/testing/selftests/yama/Makefile | 19 ++ tools/testing/selftests/yama/config | 2 + tools/testing/selftests/yama/test_omayexec.c | 276 +++++++++++++++++++ 15 files changed, 439 insertions(+), 4 deletions(-) create mode 100644 tools/testing/selftests/yama/.gitignore create mode 100644 tools/testing/selftests/yama/Makefile create mode 100644 tools/testing/selftests/yama/config create mode 100644 tools/testing/selftests/yama/test_omayexec.c