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Subject[RFC PATCH v3 1/3] ima: extend clone() with IMA namespace support
Date
From: Yuqiong Sun <suny@us.ibm.com>

Add new CONFIG_IMA_NS config option. Let clone() create a new IMA
namespace upon CLONE_NEWUSER flag. Attach the ima_ns data structure
to user_namespace. ima_ns is allocated and freed upon IMA namespace
creation and exit, which is tied to USER namespace creation and exit.
Currently, the ima_ns contains no useful IMA data but only a dummy
interface. This patch creates the framework for namespacing the different
aspects of IMA (eg. IMA-audit, IMA-measurement, IMA-appraisal).

Changelog:
v3:
* Use CLONE_NEWUSER instead of CLONE_NEWNW flag

v2:
* Moved ima_init_ns and related functions into own file that is
always compiled; init_ima_ns will always be there
* Fixed putting of imans->parent
* Move IMA namespace creation from nsproxy into mount namespace
code; get rid of procfs operations for IMA namespace

v1:
* Use CLONE_NEWNS instead of a new CLONE_NEWIMA flag
* Use existing ima.h headers
* Move the ima_namespace.c to security/integrity/ima/ima_ns.c
* Fix typo INFO->INO
* Each namespace free's itself, removed recursively free'ing
until init_ima_ns from free_ima_ns()

Signed-off-by: Yuqiong Sun <suny@us.ibm.com>
Signed-off-by: Mehmet Kayaalp <mkayaalp@linux.vnet.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
---
include/linux/ima.h | 64 ++++++++++++++++++++++++
include/linux/user_namespace.h | 4 ++
init/Kconfig | 8 +++
kernel/user.c | 7 +++
kernel/user_namespace.c | 18 +++++++
security/integrity/ima/Makefile | 3 +-
security/integrity/ima/ima.h | 4 ++
security/integrity/ima/ima_init.c | 4 ++
security/integrity/ima/ima_init_ima_ns.c | 37 ++++++++++++++
security/integrity/ima/ima_ns.c | 86 ++++++++++++++++++++++++++++++++
10 files changed, 234 insertions(+), 1 deletion(-)
create mode 100644 security/integrity/ima/ima_init_ima_ns.c
create mode 100644 security/integrity/ima/ima_ns.c

diff --git a/include/linux/ima.h b/include/linux/ima.h
index 0e4647e0eb60..8bca67df0ad3 100644
--- a/include/linux/ima.h
+++ b/include/linux/ima.h
@@ -12,6 +12,7 @@

#include <linux/fs.h>
#include <linux/kexec.h>
+#include <linux/user_namespace.h>
struct linux_binprm;

#ifdef CONFIG_IMA
@@ -105,4 +106,67 @@ static inline int ima_inode_removexattr(struct dentry *dentry,
return 0;
}
#endif /* CONFIG_IMA_APPRAISE */
+
+struct ima_namespace {
+ struct kref kref;
+ struct ima_namespace *parent;
+};
+
+extern struct ima_namespace init_ima_ns;
+
+void imans_install(struct ns_common *new);
+
+static inline struct ima_namespace *to_ima_ns(struct ns_common *ns)
+{
+ return container_of(ns, struct user_namespace, ns)->ima_ns;
+}
+
+#ifdef CONFIG_IMA_NS
+
+void free_ima_ns(struct kref *kref);
+
+static inline struct ima_namespace *get_ima_ns(struct ima_namespace *ns)
+{
+ BUG_ON(!ns);
+ if (ns)
+ kref_get(&ns->kref);
+ return ns;
+}
+
+static inline void put_ima_ns(struct ima_namespace *ns)
+{
+ BUG_ON(!ns);
+ if (ns)
+ kref_put(&ns->kref, free_ima_ns);
+}
+
+struct ima_namespace *copy_ima(struct ima_namespace *old_ns);
+
+static inline struct ima_namespace *get_current_ns(void)
+{
+ return current_user_ns()->ima_ns;
+}
+
+#else
+
+static inline struct ima_namespace *get_ima_ns(struct ima_namespace *ns)
+{
+ return ns;
+}
+
+static inline void put_ima_ns(struct ima_namespace *ns)
+{
+ return;
+}
+
+static inline struct ima_namespace *copy_ima(struct ima_namespace *old_ns)
+{
+ return old_ns;
+}
+
+static inline struct ima_namespace *get_current_ns(void)
+{
+ return NULL;
+}
+#endif /* CONFIG_IMA_NS */
#endif /* _LINUX_IMA_H */
diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index d6b74b91096b..8884b22d991c 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -36,6 +36,7 @@ struct uid_gid_map { /* 64 bytes -- 1 cache line */
#define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED

struct ucounts;
+struct ima_namespace;

enum ucount_type {
UCOUNT_USER_NAMESPACES,
@@ -76,6 +77,9 @@ struct user_namespace {
#endif
struct ucounts *ucounts;
int ucount_max[UCOUNT_COUNTS];
+#ifdef CONFIG_IMA
+ struct ima_namespace *ima_ns;
+#endif
} __randomize_layout;

struct ucounts {
diff --git a/init/Kconfig b/init/Kconfig
index a9a2e2c86671..a1ad5384e081 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -931,6 +931,14 @@ config NET_NS
help
Allow user space to create what appear to be multiple instances
of the network stack.
+config IMA_NS
+ bool "IMA namespace"
+ depends on IMA
+ default y
+ help
+ Allow the creation of IMA namespaces for each mount namespace.
+ Namespaced IMA data enables having IMA features work separately
+ for each mount namespace.

endif # NAMESPACES

diff --git a/kernel/user.c b/kernel/user.c
index 9a20acce460d..31c946f3adce 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -19,6 +19,10 @@
#include <linux/user_namespace.h>
#include <linux/proc_ns.h>

+#ifdef CONFIG_IMA
+extern struct ima_namespace init_ima_ns;
+#endif
+
/*
* userns count is 1 for root user, 1 for init_uts_ns,
* and 1 for... ?
@@ -66,6 +70,9 @@ struct user_namespace init_user_ns = {
.persistent_keyring_register_sem =
__RWSEM_INITIALIZER(init_user_ns.persistent_keyring_register_sem),
#endif
+#ifdef CONFIG_IMA
+ .ima_ns = &init_ima_ns,
+#endif
};
EXPORT_SYMBOL_GPL(init_user_ns);

diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 246d4d4ce5c7..7d6e7d6e6a34 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -25,6 +25,7 @@
#include <linux/fs_struct.h>
#include <linux/bsearch.h>
#include <linux/sort.h>
+#include <linux/ima.h>

static struct kmem_cache *user_ns_cachep __read_mostly;
static DEFINE_MUTEX(userns_state_mutex);
@@ -140,8 +141,20 @@ int create_user_ns(struct cred *new)
if (!setup_userns_sysctls(ns))
goto fail_keyring;

+#if CONFIG_IMA
+ ns->ima_ns = copy_ima(parent_ns->ima_ns);
+ if (IS_ERR(ns->ima_ns)) {
+ ret = PTR_ERR(ns->ima_ns);
+ goto fail_userns_sysctls;
+ }
+#endif
+
set_cred_user_ns(new, ns);
return 0;
+#if CONFIG_IMA
+fail_userns_sysctls:
+ retire_userns_sysctls(ns);
+#endif
fail_keyring:
#ifdef CONFIG_PERSISTENT_KEYRINGS
key_put(ns->persistent_keyring_register);
@@ -195,6 +208,9 @@ static void free_user_ns(struct work_struct *work)
kfree(ns->projid_map.forward);
kfree(ns->projid_map.reverse);
}
+#ifdef CONFIG_IMA
+ put_ima_ns(ns->ima_ns);
+#endif
retire_userns_sysctls(ns);
#ifdef CONFIG_PERSISTENT_KEYRINGS
key_put(ns->persistent_keyring_register);
@@ -1285,6 +1301,8 @@ static int userns_install(struct nsproxy *nsproxy, struct ns_common *ns)
put_user_ns(cred->user_ns);
set_cred_user_ns(cred, get_user_ns(user_ns));

+ imans_install(ns);
+
return commit_creds(cred);
}

diff --git a/security/integrity/ima/Makefile b/security/integrity/ima/Makefile
index d921dc4f9eb0..cc60f726e651 100644
--- a/security/integrity/ima/Makefile
+++ b/security/integrity/ima/Makefile
@@ -7,7 +7,8 @@
obj-$(CONFIG_IMA) += ima.o

ima-y := ima_fs.o ima_queue.o ima_init.o ima_main.o ima_crypto.o ima_api.o \
- ima_policy.o ima_template.o ima_template_lib.o
+ ima_policy.o ima_template.o ima_template_lib.o ima_init_ima_ns.o
ima-$(CONFIG_IMA_APPRAISE) += ima_appraise.o
+ima-$(CONFIG_IMA_NS) += ima_ns.o
ima-$(CONFIG_HAVE_IMA_KEXEC) += ima_kexec.o
obj-$(CONFIG_IMA_BLACKLIST_KEYRING) += ima_mok.o
diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
index d52b487ad259..e98c11c7cf75 100644
--- a/security/integrity/ima/ima.h
+++ b/security/integrity/ima/ima.h
@@ -291,6 +291,10 @@ static inline int ima_read_xattr(struct dentry *dentry,

#endif /* CONFIG_IMA_APPRAISE */

+int ima_ns_init(void);
+struct ima_namespace;
+int ima_init_namespace(struct ima_namespace *ns);
+
/* LSM based policy rules require audit */
#ifdef CONFIG_IMA_LSM_RULES

diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c
index 2967d497a665..7f884a71fa1c 100644
--- a/security/integrity/ima/ima_init.c
+++ b/security/integrity/ima/ima_init.c
@@ -137,5 +137,9 @@ int __init ima_init(void)

ima_init_policy();

+ rc = ima_ns_init();
+ if (rc != 0)
+ return rc;
+
return ima_fs_init();
}
diff --git a/security/integrity/ima/ima_init_ima_ns.c b/security/integrity/ima/ima_init_ima_ns.c
new file mode 100644
index 000000000000..52cb94b1d392
--- /dev/null
+++ b/security/integrity/ima/ima_init_ima_ns.c
@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2016-2018 IBM Corporation
+ * Author:
+ * Yuqiong Sun <suny@us.ibm.com>
+ * Stefan Berger <stefanb@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ */
+
+#include <linux/export.h>
+#include <linux/user_namespace.h>
+#include <linux/ima.h>
+
+int ima_init_namespace(struct ima_namespace *ns)
+{
+ return 0;
+}
+
+int __init ima_ns_init(void)
+{
+ return ima_init_namespace(&init_ima_ns);
+}
+
+struct ima_namespace init_ima_ns = {
+ .kref = KREF_INIT(1),
+ .parent = NULL,
+};
+EXPORT_SYMBOL(init_ima_ns);
+
+void imans_install(struct ns_common *new)
+{
+ struct ima_namespace *ns = to_ima_ns(new);
+
+ get_ima_ns(ns);
+}
diff --git a/security/integrity/ima/ima_ns.c b/security/integrity/ima/ima_ns.c
new file mode 100644
index 000000000000..62148908015a
--- /dev/null
+++ b/security/integrity/ima/ima_ns.c
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2016-2018 IBM Corporation
+ * Author:
+ * Yuqiong Sun <suny@us.ibm.com>
+ * Stefan Berger <stefanb@linux.vnet.ibm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 2 of the License.
+ */
+
+#include <linux/kref.h>
+#include <linux/slab.h>
+#include <linux/ima.h>
+#include <linux/mount.h>
+
+#include "ima.h"
+
+static struct ima_namespace *create_ima_ns(void)
+{
+ struct ima_namespace *ima_ns;
+
+ ima_ns = kmalloc(sizeof(*ima_ns), GFP_KERNEL);
+ if (ima_ns)
+ kref_init(&ima_ns->kref);
+
+ return ima_ns;
+}
+
+/**
+ * Clone a new ns copying an original ima namespace, setting refcount to 1
+ *
+ * @old_ns: old ima namespace to clone
+ * Return ERR_PTR(-ENOMEM) on error (failure to kmalloc), new ns otherwise
+ */
+static struct ima_namespace *clone_ima_ns(struct ima_namespace *old_ns)
+{
+ struct ima_namespace *ns;
+
+ ns = create_ima_ns();
+ if (!ns)
+ return ERR_PTR(-ENOMEM);
+
+ get_ima_ns(old_ns);
+ ns->parent = old_ns;
+
+ ima_init_namespace(ns);
+
+ return ns;
+}
+
+/**
+ * Copy task's ima namespace, or clone it if flags specifies CLONE_NEWNS.
+ *
+ * @flags: flags used in the clone syscall
+ * @old_ns: old ima namespace to clone
+ */
+
+struct ima_namespace *copy_ima(struct ima_namespace *old_ns)
+{
+ struct ima_namespace *new_ns;
+
+ BUG_ON(!old_ns);
+ get_ima_ns(old_ns);
+
+ new_ns = clone_ima_ns(old_ns);
+ put_ima_ns(old_ns);
+
+ return new_ns;
+}
+
+static void destroy_ima_ns(struct ima_namespace *ns)
+{
+ put_ima_ns(ns->parent);
+ kfree(ns);
+}
+
+void free_ima_ns(struct kref *kref)
+{
+ struct ima_namespace *ns;
+
+ ns = container_of(kref, struct ima_namespace, kref);
+ BUG_ON(ns == &init_ima_ns);
+
+ destroy_ima_ns(ns);
+}
--
2.14.3
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