From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752716AbbEYMdi (ORCPT ); Mon, 25 May 2015 08:33:38 -0400 Received: from mailout4.w1.samsung.com ([210.118.77.14]:40320 "EHLO mailout4.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752322AbbEYMdN (ORCPT ); Mon, 25 May 2015 08:33:13 -0400 X-AuditID: cbfec7f4-f79c56d0000012ee-42-55631685c676 From: Lukasz Pawelczyk To: "David S. Miller" , "Eric W. Biederman" , "Kirill A. Shutemov" , "Serge E. Hallyn" , Al Viro , Alexey Dobriyan , Andrew Morton , Andy Lutomirski , Casey Schaufler , David Howells , Fabian Frederick , Greg KH , James Morris , Jeff Layton , Jingoo Han , Joe Perches , John Johansen , Jonathan Corbet , Kees Cook , Lukasz Pawelczyk , Mauro Carvalho Chehab , Miklos Szeredi , Oleg Nesterov , Paul Moore , Stephen Smalley , Tetsuo Handa , Zefan Li , Rafal Krypa , linux-doc@vger.kernel.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, containers@lists.linux-foundation.org Cc: Lukasz Pawelczyk Subject: [PATCH v2 1/7] user_ns: 3 new hooks for user namespace operations Date: Mon, 25 May 2015 14:32:36 +0200 Message-id: <1432557162-19123-2-git-send-email-l.pawelczyk@samsung.com> X-Mailer: git-send-email 2.1.0 In-reply-to: <1432557162-19123-1-git-send-email-l.pawelczyk@samsung.com> References: <1432209222-8479-1-git-send-email-l.pawelczyk@samsung.com> <1432557162-19123-1-git-send-email-l.pawelczyk@samsung.com> X-Brightmail-Tracker: H4sIAAAAAAAAAzWRa0iTYRTHffY+ezZni5fl5c1AYiCC5GXUh6OY9K0XP4RdrAyhpr6Yuqlt GhoGU+cldZazMJ1Cw+yis6mllVPM5W15TWldRC01u6oVgpmaeaFvv3P+vz/nwxFSkgHsLoxN SOZUCXKFlIhw39+eVz7ZrlFh/t0dO6E0IwQqzCYCE81/CJjufCEw8ywXQcWQFsN85gqG9Wat APJXlglkVZkJrH/bB0XTx2DUOMIH0+9JBIbJaQy9i9kE+guUYCo2UtCvN/Lg4VIeAWPObQyj LRUEfhROEdDn6QRQW6fhQ+1sKsxaGihoas9GMKYvxWDQzvNhTn+PgueWKgqGhgcFMLTWwz8k ZSe/r2G2XKMjrEHzErOP7r/lsU/LxwWs3RLOajvn+OzTuhoe23tzBbPtlSYBW/LmLmKrikr4 7M+P7zYKVzfcurbPiF2ssVOhe86IgqI5RexFTuUXfE50ftwYn5QblGr4qkcatCbLR45Chj7A DDxoFWyzKzM8YSb5SCSU0NWI6eq8ztseMnhMv92KNi1C+zNLw23UZuBM60SMRTdFNgOK9mKq DVl4k3fRIYx+fHargGlPZmx2dcsR04eZVkMm3j7nwdRb1rccR5pl6steb7GE1iKmdZy+hsS3 kEMNcuFSopLUkTFKma9arlSnJMT4RiUqG9H2kxefoKruQCuihUi6Q1wfFxkm4csvqtOUVsQI KamzWLa6sRJHy9MucarEs6oUBae2oj1CLHUTV7YsnJDQMfJkLp7jkjjV/5QndHTXoCtJGb8K m0/ZbHttg+1QQLUXN+H04IWZ47qb2eaTEWI/75HED33FDo/x6YzpVLDHJQ90pb9/8TqUs2nm O/qtnNuJajkxKwKXwh33e0d/cvF0CS/zsYYFHK3e7WWRysiNMtXliIYjvMYW3FzvcS3Hidgv /J0qFXEJB5edArylWH1eLvOmVGr5P+I9lrXgAgAA Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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 f014f25..b6e0c3d 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1260,6 +1260,23 @@ * 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 a 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 @@ -1611,6 +1628,12 @@ union security_list_options { struct audit_context *actx); void (*audit_rule_free)(void *lsmrule); #endif /* CONFIG_AUDIT */ + +#ifdef CONFIG_SECURITY + 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_SECURITY */ }; struct security_hook_heads { @@ -1822,6 +1845,11 @@ struct security_hook_heads { struct list_head audit_rule_match; struct list_head audit_rule_free; #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_SECURITY + struct list_head userns_create; + struct list_head userns_free; + struct list_head userns_setns; +#endif /* CONFIG_SECURITY */ }; /* diff --git a/include/linux/security.h b/include/linux/security.h index 8c8175d..ec17ae1 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -1583,6 +1583,29 @@ static inline void security_audit_rule_free(void *lsmrule) #endif /* CONFIG_SECURITY */ #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_SECURITY +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_SECURITY */ + #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 bd4c5f6..e902f3b 100644 --- a/security/security.c +++ b/security/security.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #define MAX_LSM_EVM_XATTR 2 @@ -1541,6 +1542,25 @@ int security_audit_rule_match(u32 secid, u32 field, u32 op, void *lsmrule, } #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_SECURITY + +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_SECURITY */ + struct security_hook_heads security_hook_heads = { .binder_set_context_mgr = LIST_HEAD_INIT(security_hook_heads.binder_set_context_mgr), @@ -1885,4 +1905,12 @@ struct security_hook_heads security_hook_heads = { .audit_rule_free = LIST_HEAD_INIT(security_hook_heads.audit_rule_free), #endif /* CONFIG_AUDIT */ +#ifdef CONFIG_SECURITY + .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_SECURITY */ }; -- 2.1.0