From patchwork Fri Jul 24 10:04:35 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukasz Pawelczyk X-Patchwork-Id: 6858981 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id 8C5BD9F380 for ; Fri, 24 Jul 2015 10:08:41 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 6E22820631 for ; Fri, 24 Jul 2015 10:08:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1046E20609 for ; Fri, 24 Jul 2015 10:08:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752492AbbGXKFc (ORCPT ); Fri, 24 Jul 2015 06:05:32 -0400 Received: from mailout3.w1.samsung.com ([210.118.77.13]:38651 "EHLO mailout3.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750740AbbGXKF1 (ORCPT ); Fri, 24 Jul 2015 06:05:27 -0400 Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout3.w1.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTP id <0NRZ005I4LD0X190@mailout3.w1.samsung.com>; Fri, 24 Jul 2015 11:05:24 +0100 (BST) X-AuditID: cbfec7f4-f79c56d0000012ee-74-55b20de47177 Received: from eusync2.samsung.com ( [203.254.199.212]) by eucpsbgm1.samsung.com (EUCPMTA) with SMTP id 53.FE.04846.4ED02B55; Fri, 24 Jul 2015 11:05:24 +0100 (BST) Received: from amdc2143.DIGITAL.local ([106.120.53.33]) by eusync2.samsung.com (Oracle Communications Messaging Server 7.0.5.31.0 64bit (built May 5 2014)) with ESMTPA id <0NRZ00EPNLC23A60@eusync2.samsung.com>; Fri, 24 Jul 2015 11:05:23 +0100 (BST) From: Lukasz Pawelczyk To: "Eric W. Biederman" , "Serge E. Hallyn" , Al Viro , Alexey Dobriyan , Andrew Morton , Andy Lutomirski , Arnd Bergmann , Casey Schaufler , David Howells , Eric Dumazet , Eric Paris , Fabian Frederick , Greg KH , James Morris , Jiri Slaby , Joe Perches , John Johansen , Jonathan Corbet , Kees Cook , Lukasz Pawelczyk , Mauro Carvalho Chehab , NeilBrown , Oleg Nesterov , Paul Moore , Stephen Smalley , Tetsuo Handa , Zefan Li , linux-doc@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov Cc: havner@gmail.com Subject: [PATCH v3 01/11] user_ns: 3 new LSM hooks for user namespace operations Date: Fri, 24 Jul 2015 12:04:35 +0200 Message-id: <1437732285-11524-2-git-send-email-l.pawelczyk@samsung.com> X-Mailer: git-send-email 2.4.3 In-reply-to: <1437732285-11524-1-git-send-email-l.pawelczyk@samsung.com> References: <1437732285-11524-1-git-send-email-l.pawelczyk@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAAzWRWUxTYRCF/du/9xa0yaWg3IBirMEtitSAGQi4ECN/jBokEiMvWuEGUFqw ZdWXssoiSIoGwyIQKLLKEiECVhC0ILsBTdSwyGIMZTUokYoIJb6dme+cOQ8j5Is7sI0wSBHG KRWyYAlljrv/dgwdmRTV+Tjqy2jIijkHudWVFKxq9DSMNKxQMNl6D8FcrBHDWkM8DVP6cRqS v/byIcX4m4K4omoK1gyHIX3CG3JGJzB0LiVQ8LBmgQc9qXLo0RTyoDCxGMNL3TsMg025FCzc H6dAk5RGQ0WVWgAV36JAl6/GUN+SgOCLJgtDTvycANqbi/iQOdmGoX+gj4b+1Q7BqT1kdGYV E+OKBpFsdRpFctTvMWnMHqZJQV04+dh8lcS/mRWQxqpyHul8bMSkJa+SJkXpmQKyOPUZk+cP 1q29P31Jle478rL1NXfz54KDIjjl0RPXzQNLS2d5oXVuUYakaaRGxcdSkJmQZZzYXk0aval3 sAMj1VQKMheKGS1i49Zq0OYQw2Njx37xN1wU48guD+j4G8CKqTdjM2qq0AbgM1bsn7lF0ylL xottTk4zBTBjz45lq01axHiya58MeLPOju2rXjJpM4aw3YM/TFnxuic1O5fOQKICtKUcbefC /UJVNwLkUgeVTK4KVwQ4+IXI69Dme5deoCK9axtihEiyTdSqqfURC2QRqmh5G2KFfImVaIt+ fSXyl0Xf4ZQh15ThwZyqDdkKscRalNc0f1nMBMjCuFscF8op/1Oe0MxGjcjNhoLbswtSo87g pD2f5b38IT8d1con3yZozx44o9g1dKHn+Gm3aAv73Y7Pgqy1dkGBMyeduYNPIm0veVxxdwku ieySeimGE6f3d80HcNKdnq+kW1+7esQ8je83cOM6+lHmggW11712X4lOn+S8ispsXNq1F8Ul yKM7926pJSXBqkCZ9BBfqZL9AzxboKDaAgAA Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-8.1 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This commit implements 3 new LSM hooks that provide the means for LSMs to embed their own security context within user namespace, effectively creating some sort of a user_ns related security namespace. The first one to take advantage of this mechanism is Smack. The hooks has been documented in the in the security.h below. Signed-off-by: Lukasz Pawelczyk Reviewed-by: Casey Schaufler Acked-by: Paul Moore --- include/linux/lsm_hooks.h | 28 ++++++++++++++++++++++++++++ include/linux/security.h | 23 +++++++++++++++++++++++ include/linux/user_namespace.h | 4 ++++ kernel/user.c | 3 +++ kernel/user_namespace.c | 18 ++++++++++++++++++ security/security.c | 28 ++++++++++++++++++++++++++++ 6 files changed, 104 insertions(+) diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index 9429f05..228558c 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1261,6 +1261,23 @@ * audit_rule_init. * @rule contains the allocated rule * + * @userns_create: + * Allocates and fills the security part of a new user namespace. + * @ns points to a newly created user namespace. + * Returns 0 or an error code. + * + * @userns_free: + * Deallocates the security part of a user namespace. + * @ns points to a user namespace about to be destroyed. + * + * @userns_setns: + * Run during a setns syscall to add a process to an already existing + * user namespace. Returning failure here will block the operation + * requested from userspace (setns() with CLONE_NEWUSER). + * @nsproxy contains nsproxy to which the user namespace will be assigned. + * @ns contains user namespace that is to be incorporated to the nsproxy. + * Returns 0 or an error code. + * * @inode_notifysecctx: * Notify the security module of what the security context of an inode * should be. Initializes the incore security context managed by the @@ -1613,6 +1630,12 @@ union security_list_options { struct audit_context *actx); void (*audit_rule_free)(void *lsmrule); #endif /* CONFIG_AUDIT */ + +#ifdef CONFIG_USER_NS + int (*userns_create)(struct user_namespace *ns); + void (*userns_free)(struct user_namespace *ns); + int (*userns_setns)(struct nsproxy *nsproxy, struct user_namespace *ns); +#endif /* CONFIG_USER_NS */ }; struct security_hook_heads { @@ -1824,6 +1847,11 @@ struct security_hook_heads { struct list_head audit_rule_match; struct list_head audit_rule_free; #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_USER_NS + struct list_head userns_create; + struct list_head userns_free; + struct list_head userns_setns; +#endif /* CONFIG_USER_NS */ }; /* diff --git a/include/linux/security.h b/include/linux/security.h index 79d85dd..1b0eccc 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1584,6 +1584,29 @@ static inline void security_audit_rule_free(void *lsmrule) #endif /* CONFIG_SECURITY */ #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_USER_NS +int security_userns_create(struct user_namespace *ns); +void security_userns_free(struct user_namespace *ns); +int security_userns_setns(struct nsproxy *nsproxy, struct user_namespace *ns); + +#else + +static inline int security_userns_create(struct user_namespace *ns) +{ + return 0; +} + +static inline void security_userns_free(struct user_namespace *ns) +{ } + +static inline int security_userns_setns(struct nsproxy *nsproxy, + struct user_namespace *ns) +{ + return 0; +} + +#endif /* CONFIG_USER_NS */ + #ifdef CONFIG_SECURITYFS extern struct dentry *securityfs_create_file(const char *name, umode_t mode, diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index 8297e5b..a9400cc 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -39,6 +39,10 @@ struct user_namespace { struct key *persistent_keyring_register; struct rw_semaphore persistent_keyring_register_sem; #endif + +#ifdef CONFIG_SECURITY + void *security; +#endif }; extern struct user_namespace init_user_ns; diff --git a/kernel/user.c b/kernel/user.c index b069ccb..ce5419e 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -59,6 +59,9 @@ struct user_namespace init_user_ns = { .persistent_keyring_register_sem = __RWSEM_INITIALIZER(init_user_ns.persistent_keyring_register_sem), #endif +#ifdef CONFIG_SECURITY + .security = NULL, +#endif }; EXPORT_SYMBOL_GPL(init_user_ns); diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 4109f83..cadffb6 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -22,6 +22,7 @@ #include #include #include +#include static struct kmem_cache *user_ns_cachep __read_mostly; static DEFINE_MUTEX(userns_state_mutex); @@ -108,6 +109,15 @@ int create_user_ns(struct cred *new) set_cred_user_ns(new, ns); +#ifdef CONFIG_SECURITY + ret = security_userns_create(ns); + if (ret) { + ns_free_inum(&ns->ns); + kmem_cache_free(user_ns_cachep, ns); + return ret; + } +#endif + #ifdef CONFIG_PERSISTENT_KEYRINGS init_rwsem(&ns->persistent_keyring_register_sem); #endif @@ -143,6 +153,9 @@ void free_user_ns(struct user_namespace *ns) #ifdef CONFIG_PERSISTENT_KEYRINGS key_put(ns->persistent_keyring_register); #endif +#ifdef CONFIG_SECURITY + security_userns_free(ns); +#endif ns_free_inum(&ns->ns); kmem_cache_free(user_ns_cachep, ns); ns = parent; @@ -969,6 +982,7 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns) { struct user_namespace *user_ns = to_user_ns(ns); struct cred *cred; + int err; /* Don't allow gaining capabilities by reentering * the same user namespace. @@ -986,6 +1000,10 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns) if (!ns_capable(user_ns, CAP_SYS_ADMIN)) return -EPERM; + err = security_userns_setns(nsproxy, user_ns); + if (err) + return err; + cred = prepare_creds(); if (!cred) return -ENOMEM; diff --git a/security/security.c b/security/security.c index 595fffa..5e66388 100644 --- a/security/security.c +++ b/security/security.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #define MAX_LSM_EVM_XATTR 2 @@ -1542,6 +1543,25 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule, } #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_USER_NS + +int security_userns_create(struct user_namespace *ns) +{ + return call_int_hook(userns_create, 0, ns); +} + +void security_userns_free(struct user_namespace *ns) +{ + call_void_hook(userns_free, ns); +} + +int security_userns_setns(struct nsproxy *nsproxy, struct user_namespace *ns) +{ + return call_int_hook(userns_setns, 0, nsproxy, ns); +} + +#endif /* CONFIG_USER_NS */ + struct security_hook_heads security_hook_heads = { .binder_set_context_mgr = LIST_HEAD_INIT(security_hook_heads.binder_set_context_mgr), @@ -1886,4 +1906,12 @@ struct security_hook_heads security_hook_heads = { .audit_rule_free = LIST_HEAD_INIT(security_hook_heads.audit_rule_free), #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_USER_NS + .userns_create = + LIST_HEAD_INIT(security_hook_heads.userns_create), + .userns_free = + LIST_HEAD_INIT(security_hook_heads.userns_free), + .userns_setns = + LIST_HEAD_INIT(security_hook_heads.userns_setns), +#endif /* CONFIG_USER_NS */ };