apparmor: split apparmor policy namespaces code into its own file

Policy namespaces will be diverging from profile management and
expanding so put it in its own file.

Signed-off-by: John Johansen <john.johansen@canonical.com>

security/apparmor/include/policy_ns.h

@@ -0,0 +1,137 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor policy definitions.
+ *
+ * Copyright (C) 1998-2008 Novell/SUSE
+ * Copyright 2009-2017 Canonical Ltd.
+ *
+ * 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.
+ */
+
+#ifndef __AA_NAMESPACE_H
+#define __AA_NAMESPACE_H
+
+#include <linux/kref.h>
+
+#include "apparmor.h"
+#include "apparmorfs.h"
+#include "policy.h"
+
+
+/* struct aa_ns_acct - accounting of profiles in namespace
+ * @max_size: maximum space allowed for all profiles in namespace
+ * @max_count: maximum number of profiles that can be in this namespace
+ * @size: current size of profiles
+ * @count: current count of profiles (includes null profiles)
+ */
+struct aa_ns_acct {
+	int max_size;
+	int max_count;
+	int size;
+	int count;
+};
+
+/* struct aa_namespace - namespace for a set of profiles
+ * @base: common policy
+ * @parent: parent of namespace
+ * @lock: lock for modifying the object
+ * @acct: accounting for the namespace
+ * @unconfined: special unconfined profile for the namespace
+ * @sub_ns: list of namespaces under the current namespace.
+ * @uniq_null: uniq value used for null learning profiles
+ * @uniq_id: a unique id count for the profiles in the namespace
+ * @dents: dentries for the namespaces file entries in apparmorfs
+ *
+ * An aa_namespace defines the set profiles that are searched to determine
+ * which profile to attach to a task.  Profiles can not be shared between
+ * aa_namespaces and profile names within a namespace are guaranteed to be
+ * unique.  When profiles in separate namespaces have the same name they
+ * are NOT considered to be equivalent.
+ *
+ * Namespaces are hierarchical and only namespaces and profiles below the
+ * current namespace are visible.
+ *
+ * Namespace names must be unique and can not contain the characters :/\0
+ */
+struct aa_namespace {
+	struct aa_policy base;
+	struct aa_namespace *parent;
+	struct mutex lock;
+	struct aa_ns_acct acct;
+	struct aa_profile *unconfined;
+	struct list_head sub_ns;
+	atomic_t uniq_null;
+	long uniq_id;
+
+	struct dentry *dents[AAFS_NS_SIZEOF];
+};
+
+extern struct aa_namespace *root_ns;
+
+extern const char *aa_hidden_ns_name;
+
+bool aa_ns_visible(struct aa_namespace *curr, struct aa_namespace *view);
+const char *aa_ns_name(struct aa_namespace *parent, struct aa_namespace *child);
+void aa_free_namespace(struct aa_namespace *ns);
+int aa_alloc_root_ns(void);
+void aa_free_root_ns(void);
+void aa_free_namespace_kref(struct kref *kref);
+
+struct aa_namespace *aa_find_namespace(struct aa_namespace *root,
+				       const char *name);
+struct aa_namespace *aa_prepare_namespace(const char *name);
+void __aa_remove_namespace(struct aa_namespace *ns);
+
+static inline struct aa_profile *aa_deref_parent(struct aa_profile *p)
+{
+	return rcu_dereference_protected(p->parent,
+					 mutex_is_locked(&p->ns->lock));
+}
+
+/**
+ * aa_get_namespace - increment references count on @ns
+ * @ns: namespace to increment reference count of (MAYBE NULL)
+ *
+ * Returns: pointer to @ns, if @ns is NULL returns NULL
+ * Requires: @ns must be held with valid refcount when called
+ */
+static inline struct aa_namespace *aa_get_namespace(struct aa_namespace *ns)
+{
+	if (ns)
+		aa_get_profile(ns->unconfined);
+
+	return ns;
+}
+
+/**
+ * aa_put_namespace - decrement refcount on @ns
+ * @ns: namespace to put reference of
+ *
+ * Decrement reference count of @ns and if no longer in use free it
+ */
+static inline void aa_put_namespace(struct aa_namespace *ns)
+{
+	if (ns)
+		aa_put_profile(ns->unconfined);
+}
+
+/**
+ * __aa_find_namespace - find a namespace on a list by @name
+ * @head: list to search for namespace on  (NOT NULL)
+ * @name: name of namespace to look for  (NOT NULL)
+ *
+ * Returns: unrefcounted namespace
+ *
+ * Requires: rcu_read_lock be held
+ */
+static inline struct aa_namespace *__aa_find_namespace(struct list_head *head,
+						const char *name)
+{
+	return (struct aa_namespace *)__policy_find(head, name);
+}
+
+#endif /* AA_NAMESPACE_H */