From patchwork Thu Mar 26 20:27:24 2020 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: 11461111 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 24AD315AB for ; Thu, 26 Mar 2020 20:28:21 +0000 (UTC) Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.kernel.org (Postfix) with SMTP id 607AB20775 for ; Thu, 26 Mar 2020 20:28:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 607AB20775 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=digikod.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kernel-hardening-return-18239-patchwork-kernel-hardening=patchwork.kernel.org@lists.openwall.com Received: (qmail 15975 invoked by uid 550); 26 Mar 2020 20:27:56 -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 15876 invoked from network); 26 Mar 2020 20:27:55 -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 , Andy Lutomirski , Arnd Bergmann , Casey Schaufler , James Morris , Jann Horn , Jonathan Corbet , Kees Cook , Michael Kerrisk , =?utf-8?q?Micka=C3=ABl_Sala=C3=BC?= =?utf-8?q?n?= , "Serge E . Hallyn" , Shuah Khan , Vincent Dagonneau , kernel-hardening@lists.openwall.com, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-security-module@vger.kernel.org, x86@kernel.org Subject: [PATCH v15 03/10] landlock: Set up the security framework and manage credentials Date: Thu, 26 Mar 2020 21:27:24 +0100 Message-Id: <20200326202731.693608-4-mic@digikod.net> X-Mailer: git-send-email 2.26.0.rc2 In-Reply-To: <20200326202731.693608-1-mic@digikod.net> References: <20200326202731.693608-1-mic@digikod.net> MIME-Version: 1.0 X-Antivirus: Dr.Web (R) for Unix mail servers drweb plugin ver.6.0.2.8 X-Antivirus-Code: 0x100000 A process credentials point to a Landlock domain, which is underneath implemented with a ruleset. In the following commits, this domain is used to check and enforce the ptrace and filesystem security policies. A domain is inherited from a parent to its child the same way a thread inherits a seccomp policy. Signed-off-by: Mickaël Salaün Cc: Andy Lutomirski Cc: James Morris Cc: Kees Cook Cc: Serge E. Hallyn --- Changes since v14: * Uses pr_fmt from common.h . * Constify variables. * Remove useless NULL initialization. Changes since v13: * totally get ride of the seccomp dependency * only keep credential management and LSM setup. Previous version: https://lore.kernel.org/lkml/20191104172146.30797-4-mic@digikod.net/ --- security/Kconfig | 10 +++---- security/landlock/Makefile | 3 ++- security/landlock/common.h | 20 ++++++++++++++ security/landlock/cred.c | 46 +++++++++++++++++++++++++++++++ security/landlock/cred.h | 55 ++++++++++++++++++++++++++++++++++++++ security/landlock/setup.c | 31 +++++++++++++++++++++ security/landlock/setup.h | 16 +++++++++++ 7 files changed, 175 insertions(+), 6 deletions(-) create mode 100644 security/landlock/common.h create mode 100644 security/landlock/cred.c create mode 100644 security/landlock/cred.h create mode 100644 security/landlock/setup.c create mode 100644 security/landlock/setup.h diff --git a/security/Kconfig b/security/Kconfig index 9d9981394fb0..76547b5c694d 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -278,11 +278,11 @@ endchoice config LSM string "Ordered list of enabled LSMs" - default "lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK - default "lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR - default "lockdown,yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO - default "lockdown,yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC - default "lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor" + default "landlock,lockdown,yama,loadpin,safesetid,integrity,smack,selinux,tomoyo,apparmor" if DEFAULT_SECURITY_SMACK + default "landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo" if DEFAULT_SECURITY_APPARMOR + default "landlock,lockdown,yama,loadpin,safesetid,integrity,tomoyo" if DEFAULT_SECURITY_TOMOYO + default "landlock,lockdown,yama,loadpin,safesetid,integrity" if DEFAULT_SECURITY_DAC + default "landlock,lockdown,yama,loadpin,safesetid,integrity,selinux,smack,tomoyo,apparmor" help A comma-separated list of LSMs, in initialization order. Any LSMs left off this list will be ignored. This can be diff --git a/security/landlock/Makefile b/security/landlock/Makefile index d846eba445bb..041ea242e627 100644 --- a/security/landlock/Makefile +++ b/security/landlock/Makefile @@ -1,3 +1,4 @@ obj-$(CONFIG_SECURITY_LANDLOCK) := landlock.o -landlock-y := object.o ruleset.o +landlock-y := setup.o object.o ruleset.o \ + cred.o diff --git a/security/landlock/common.h b/security/landlock/common.h new file mode 100644 index 000000000000..5dc0fe15707d --- /dev/null +++ b/security/landlock/common.h @@ -0,0 +1,20 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Landlock LSM - Common constants and helpers + * + * Copyright © 2016-2020 Mickaël Salaün + * Copyright © 2018-2020 ANSSI + */ + +#ifndef _SECURITY_LANDLOCK_COMMON_H +#define _SECURITY_LANDLOCK_COMMON_H + +#define LANDLOCK_NAME "landlock" + +#ifdef pr_fmt +#undef pr_fmt +#endif + +#define pr_fmt(fmt) LANDLOCK_NAME ": " fmt + +#endif /* _SECURITY_LANDLOCK_COMMON_H */ diff --git a/security/landlock/cred.c b/security/landlock/cred.c new file mode 100644 index 000000000000..84ecc78da800 --- /dev/null +++ b/security/landlock/cred.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Landlock LSM - Credential hooks + * + * Copyright © 2017-2019 Mickaël Salaün + * Copyright © 2018-2019 ANSSI + */ + +#include +#include + +#include "common.h" +#include "cred.h" +#include "ruleset.h" +#include "setup.h" + +static int hook_cred_prepare(struct cred *const new, + const struct cred *const old, const gfp_t gfp) +{ + const struct landlock_cred_security *cred_old = landlock_cred(old); + struct landlock_cred_security *cred_new = landlock_cred(new); + struct landlock_ruleset *dom_old; + + dom_old = cred_old->domain; + if (dom_old) { + landlock_get_ruleset(dom_old); + cred_new->domain = dom_old; + } + return 0; +} + +static void hook_cred_free(struct cred *const cred) +{ + landlock_put_ruleset_deferred(landlock_cred(cred)->domain); +} + +static struct security_hook_list landlock_hooks[] __lsm_ro_after_init = { + LSM_HOOK_INIT(cred_prepare, hook_cred_prepare), + LSM_HOOK_INIT(cred_free, hook_cred_free), +}; + +__init void landlock_add_hooks_cred(void) +{ + security_add_hooks(landlock_hooks, ARRAY_SIZE(landlock_hooks), + LANDLOCK_NAME); +} diff --git a/security/landlock/cred.h b/security/landlock/cred.h new file mode 100644 index 000000000000..d3a8b1c2a4dd --- /dev/null +++ b/security/landlock/cred.h @@ -0,0 +1,55 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Landlock LSM - Credential hooks + * + * Copyright © 2019 Mickaël Salaün + * Copyright © 2019 ANSSI + */ + +#ifndef _SECURITY_LANDLOCK_CRED_H +#define _SECURITY_LANDLOCK_CRED_H + +#include +#include +#include + +#include "ruleset.h" +#include "setup.h" + +struct landlock_cred_security { + struct landlock_ruleset *domain; +}; + +static inline struct landlock_cred_security *landlock_cred( + const struct cred *cred) +{ + return cred->security + landlock_blob_sizes.lbs_cred; +} + +static inline struct landlock_ruleset *landlock_get_current_domain(void) +{ + return landlock_cred(current_cred())->domain; +} + +/* + * The call needs to come from an RCU read-side critical section. + */ +static inline struct landlock_ruleset *landlock_get_task_domain( + const struct task_struct *const task) +{ + return landlock_cred(__task_cred(task))->domain; +} + +static inline bool landlocked(const struct task_struct *const task) +{ + bool has_dom; + + rcu_read_lock(); + has_dom = !!landlock_get_task_domain(task); + rcu_read_unlock(); + return has_dom; +} + +__init void landlock_add_hooks_cred(void); + +#endif /* _SECURITY_LANDLOCK_CRED_H */ diff --git a/security/landlock/setup.c b/security/landlock/setup.c new file mode 100644 index 000000000000..00eb78275cd8 --- /dev/null +++ b/security/landlock/setup.c @@ -0,0 +1,31 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Landlock LSM - Security framework setup + * + * Copyright © 2016-2020 Mickaël Salaün + * Copyright © 2018-2020 ANSSI + */ + +#include +#include + +#include "common.h" +#include "cred.h" +#include "setup.h" + +struct lsm_blob_sizes landlock_blob_sizes __lsm_ro_after_init = { + .lbs_cred = sizeof(struct landlock_cred_security), +}; + +static int __init landlock_init(void) +{ + pr_info("Registering hooks.\n"); + landlock_add_hooks_cred(); + return 0; +} + +DEFINE_LSM(LANDLOCK_NAME) = { + .name = LANDLOCK_NAME, + .init = landlock_init, + .blobs = &landlock_blob_sizes, +}; diff --git a/security/landlock/setup.h b/security/landlock/setup.h new file mode 100644 index 000000000000..9fdbf33fcc33 --- /dev/null +++ b/security/landlock/setup.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Landlock LSM - Security framework setup + * + * Copyright © 2016-2020 Mickaël Salaün + * Copyright © 2018-2020 ANSSI + */ + +#ifndef _SECURITY_LANDLOCK_SETUP_H +#define _SECURITY_LANDLOCK_SETUP_H + +#include + +extern struct lsm_blob_sizes landlock_blob_sizes; + +#endif /* _SECURITY_LANDLOCK_SETUP_H */