1 files changed, 433 insertions, 0 deletions
diff --git a/security/apparmor/policy_ns.c b/security/apparmor/policy_ns.c
new file mode 100644
index 000000000..fd5b7afbc
--- /dev/null
+++ b/security/apparmor/policy_ns.c
@@ -0,0 +1,433 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor policy manipulation functions
+ *
+ * Copyright (C) 1998-2008 Novell/SUSE
+ * Copyright 2009-2017 Canonical Ltd.
+ *
+ * AppArmor policy namespaces, allow for different sets of policies
+ * to be loaded for tasks within the namespace.
+ */
+
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include "include/apparmor.h"
+#include "include/cred.h"
+#include "include/policy_ns.h"
+#include "include/label.h"
+#include "include/policy.h"
+
+/* kernel label */
+struct aa_label *kernel_t;
+
+/* root profile namespace */
+struct aa_ns *root_ns;
+const char *aa_hidden_ns_name = "---";
+
+/**
+ * aa_ns_visible - test if @view is visible from @curr
+ * @curr: namespace to treat as the parent (NOT NULL)
+ * @view: namespace to test if visible from @curr (NOT NULL)
+ * @subns: whether view of a subns is allowed
+ *
+ * Returns: true if @view is visible from @curr else false
+ */
+bool aa_ns_visible(struct aa_ns *curr, struct aa_ns *view, bool subns)
+{
+	if (curr == view)
+		return true;
+
+	if (!subns)
+		return false;
+
+	for ( ; view; view = view->parent) {
+		if (view->parent == curr)
+			return true;
+	}
+
+	return false;
+}
+
+/**
+ * aa_ns_name - Find the ns name to display for @view from @curr
+ * @curr: current namespace (NOT NULL)
+ * @view: namespace attempting to view (NOT NULL)
+ * @subns: are subns visible
+ *
+ * Returns: name of @view visible from @curr
+ */
+const char *aa_ns_name(struct aa_ns *curr, struct aa_ns *view, bool subns)
+{
+	/* if view == curr then the namespace name isn't displayed */
+	if (curr == view)
+		return "";
+
+	if (aa_ns_visible(curr, view, subns)) {
+		/* at this point if a ns is visible it is in a view ns
+		 * thus the curr ns.hname is a prefix of its name.
+		 * Only output the virtualized portion of the name
+		 * Add + 2 to skip over // separating curr hname prefix
+		 * from the visible tail of the views hname
+		 */
+		return view->base.hname + strlen(curr->base.hname) + 2;
+	}
+
+	return aa_hidden_ns_name;
+}
+
+static struct aa_profile *alloc_unconfined(const char *name)
+{
+	struct aa_profile *profile;
+
+	profile = aa_alloc_null(NULL, name, GFP_KERNEL);
+	if (!profile)
+		return NULL;
+
+	profile->label.flags |= FLAG_IX_ON_NAME_ERROR |
+		FLAG_IMMUTIBLE | FLAG_NS_COUNT | FLAG_UNCONFINED;
+	profile->mode = APPARMOR_UNCONFINED;
+
+	return profile;
+}
+
+/**
+ * alloc_ns - allocate, initialize and return a new namespace
+ * @prefix: parent namespace name (MAYBE NULL)
+ * @name: a preallocated name  (NOT NULL)
+ *
+ * Returns: refcounted namespace or NULL on failure.
+ */
+static struct aa_ns *alloc_ns(const char *prefix, const char *name)
+{
+	struct aa_ns *ns;
+
+	ns = kzalloc(sizeof(*ns), GFP_KERNEL);
+	AA_DEBUG("%s(%p)\n", __func__, ns);
+	if (!ns)
+		return NULL;
+	if (!aa_policy_init(&ns->base, prefix, name, GFP_KERNEL))
+		goto fail_ns;
+
+	INIT_LIST_HEAD(&ns->sub_ns);
+	INIT_LIST_HEAD(&ns->rawdata_list);
+	mutex_init(&ns->lock);
+	init_waitqueue_head(&ns->wait);
+
+	/* released by aa_free_ns() */
+	ns->unconfined = alloc_unconfined("unconfined");
+	if (!ns->unconfined)
+		goto fail_unconfined;
+	/* ns and ns->unconfined share ns->unconfined refcount */
+	ns->unconfined->ns = ns;
+
+	atomic_set(&ns->uniq_null, 0);
+
+	aa_labelset_init(&ns->labels);
+
+	return ns;
+
+fail_unconfined:
+	aa_policy_destroy(&ns->base);
+fail_ns:
+	kfree_sensitive(ns);
+	return NULL;
+}
+
+/**
+ * aa_free_ns - free a profile namespace
+ * @ns: the namespace to free  (MAYBE NULL)
+ *
+ * Requires: All references to the namespace must have been put, if the
+ *           namespace was referenced by a profile confining a task,
+ */
+void aa_free_ns(struct aa_ns *ns)
+{
+	if (!ns)
+		return;
+
+	aa_policy_destroy(&ns->base);
+	aa_labelset_destroy(&ns->labels);
+	aa_put_ns(ns->parent);
+
+	ns->unconfined->ns = NULL;
+	aa_free_profile(ns->unconfined);
+	kfree_sensitive(ns);
+}
+
+/**
+ * aa_findn_ns  -  look up a profile namespace on the namespace list
+ * @root: namespace to search in  (NOT NULL)
+ * @name: name of namespace to find  (NOT NULL)
+ * @n: length of @name
+ *
+ * Returns: a refcounted namespace on the list, or NULL if no namespace
+ *          called @name exists.
+ *
+ * refcount released by caller
+ */
+struct aa_ns *aa_findn_ns(struct aa_ns *root, const char *name, size_t n)
+{
+	struct aa_ns *ns = NULL;
+
+	rcu_read_lock();
+	ns = aa_get_ns(__aa_findn_ns(&root->sub_ns, name, n));
+	rcu_read_unlock();
+
+	return ns;
+}
+
+/**
+ * aa_find_ns  -  look up a profile namespace on the namespace list
+ * @root: namespace to search in  (NOT NULL)
+ * @name: name of namespace to find  (NOT NULL)
+ *
+ * Returns: a refcounted namespace on the list, or NULL if no namespace
+ *          called @name exists.
+ *
+ * refcount released by caller
+ */
+struct aa_ns *aa_find_ns(struct aa_ns *root, const char *name)
+{
+	return aa_findn_ns(root, name, strlen(name));
+}
+
+/**
+ * __aa_lookupn_ns - lookup the namespace matching @hname
+ * @view: namespace to search in  (NOT NULL)
+ * @hname: hierarchical ns name  (NOT NULL)
+ * @n: length of @hname
+ *
+ * Requires: rcu_read_lock be held
+ *
+ * Returns: unrefcounted ns pointer or NULL if not found
+ *
+ * Do a relative name lookup, recursing through profile tree.
+ */
+struct aa_ns *__aa_lookupn_ns(struct aa_ns *view, const char *hname, size_t n)
+{
+	struct aa_ns *ns = view;
+	const char *split;
+
+	for (split = strnstr(hname, "//", n); split;
+	     split = strnstr(hname, "//", n)) {
+		ns = __aa_findn_ns(&ns->sub_ns, hname, split - hname);
+		if (!ns)
+			return NULL;
+
+		n -= split + 2 - hname;
+		hname = split + 2;
+	}
+
+	if (n)
+		return __aa_findn_ns(&ns->sub_ns, hname, n);
+	return NULL;
+}
+
+/**
+ * aa_lookupn_ns  -  look up a policy namespace relative to @view
+ * @view: namespace to search in  (NOT NULL)
+ * @name: name of namespace to find  (NOT NULL)
+ * @n: length of @name
+ *
+ * Returns: a refcounted namespace on the list, or NULL if no namespace
+ *          called @name exists.
+ *
+ * refcount released by caller
+ */
+struct aa_ns *aa_lookupn_ns(struct aa_ns *view, const char *name, size_t n)
+{
+	struct aa_ns *ns = NULL;
+
+	rcu_read_lock();
+	ns = aa_get_ns(__aa_lookupn_ns(view, name, n));
+	rcu_read_unlock();
+
+	return ns;
+}
+
+static struct aa_ns *__aa_create_ns(struct aa_ns *parent, const char *name,
+				    struct dentry *dir)
+{
+	struct aa_ns *ns;
+	int error;
+
+	AA_BUG(!parent);
+	AA_BUG(!name);
+	AA_BUG(!mutex_is_locked(&parent->lock));
+
+	ns = alloc_ns(parent->base.hname, name);
+	if (!ns)
+		return ERR_PTR(-ENOMEM);
+	ns->level = parent->level + 1;
+	mutex_lock_nested(&ns->lock, ns->level);
+	error = __aafs_ns_mkdir(ns, ns_subns_dir(parent), name, dir);
+	if (error) {
+		AA_ERROR("Failed to create interface for ns %s\n",
+			 ns->base.name);
+		mutex_unlock(&ns->lock);
+		aa_free_ns(ns);
+		return ERR_PTR(error);
+	}
+	ns->parent = aa_get_ns(parent);
+	list_add_rcu(&ns->base.list, &parent->sub_ns);
+	/* add list ref */
+	aa_get_ns(ns);
+	mutex_unlock(&ns->lock);
+
+	return ns;
+}
+
+/**
+ * __aa_find_or_create_ns - create an ns, fail if it already exists
+ * @parent: the parent of the namespace being created
+ * @name: the name of the namespace
+ * @dir: if not null the dir to put the ns entries in
+ *
+ * Returns: the a refcounted ns that has been add or an ERR_PTR
+ */
+struct aa_ns *__aa_find_or_create_ns(struct aa_ns *parent, const char *name,
+				     struct dentry *dir)
+{
+	struct aa_ns *ns;
+
+	AA_BUG(!mutex_is_locked(&parent->lock));
+
+	/* try and find the specified ns */
+	/* released by caller */
+	ns = aa_get_ns(__aa_find_ns(&parent->sub_ns, name));
+	if (!ns)
+		ns = __aa_create_ns(parent, name, dir);
+	else
+		ns = ERR_PTR(-EEXIST);
+
+	/* return ref */
+	return ns;
+}
+
+/**
+ * aa_prepare_ns - find an existing or create a new namespace of @name
+ * @parent: ns to treat as parent
+ * @name: the namespace to find or add  (NOT NULL)
+ *
+ * Returns: refcounted namespace or PTR_ERR if failed to create one
+ */
+struct aa_ns *aa_prepare_ns(struct aa_ns *parent, const char *name)
+{
+	struct aa_ns *ns;
+
+	mutex_lock_nested(&parent->lock, parent->level);
+	/* try and find the specified ns and if it doesn't exist create it */
+	/* released by caller */
+	ns = aa_get_ns(__aa_find_ns(&parent->sub_ns, name));
+	if (!ns)
+		ns = __aa_create_ns(parent, name, NULL);
+	mutex_unlock(&parent->lock);
+
+	/* return ref */
+	return ns;
+}
+
+static void __ns_list_release(struct list_head *head);
+
+/**
+ * destroy_ns - remove everything contained by @ns
+ * @ns: namespace to have it contents removed  (NOT NULL)
+ */
+static void destroy_ns(struct aa_ns *ns)
+{
+	if (!ns)
+		return;
+
+	mutex_lock_nested(&ns->lock, ns->level);
+	/* release all profiles in this namespace */
+	__aa_profile_list_release(&ns->base.profiles);
+
+	/* release all sub namespaces */
+	__ns_list_release(&ns->sub_ns);
+
+	if (ns->parent) {
+		unsigned long flags;
+
+		write_lock_irqsave(&ns->labels.lock, flags);
+		__aa_proxy_redirect(ns_unconfined(ns),
+				    ns_unconfined(ns->parent));
+		write_unlock_irqrestore(&ns->labels.lock, flags);
+	}
+	__aafs_ns_rmdir(ns);
+	mutex_unlock(&ns->lock);
+}
+
+/**
+ * __aa_remove_ns - remove a namespace and all its children
+ * @ns: namespace to be removed  (NOT NULL)
+ *
+ * Requires: ns->parent->lock be held and ns removed from parent.
+ */
+void __aa_remove_ns(struct aa_ns *ns)
+{
+	/* remove ns from namespace list */
+	list_del_rcu(&ns->base.list);
+	destroy_ns(ns);
+	aa_put_ns(ns);
+}
+
+/**
+ * __ns_list_release - remove all profile namespaces on the list put refs
+ * @head: list of profile namespaces  (NOT NULL)
+ *
+ * Requires: namespace lock be held
+ */
+static void __ns_list_release(struct list_head *head)
+{
+	struct aa_ns *ns, *tmp;
+
+	list_for_each_entry_safe(ns, tmp, head, base.list)
+		__aa_remove_ns(ns);
+
+}
+
+/**
+ * aa_alloc_root_ns - allocate the root profile namespace
+ *
+ * Returns: %0 on success else error
+ *
+ */
+int __init aa_alloc_root_ns(void)
+{
+	struct aa_profile *kernel_p;
+
+	/* released by aa_free_root_ns - used as list ref*/
+	root_ns = alloc_ns(NULL, "root");
+	if (!root_ns)
+		return -ENOMEM;
+
+	kernel_p = alloc_unconfined("kernel_t");
+	if (!kernel_p) {
+		destroy_ns(root_ns);
+		aa_free_ns(root_ns);
+		return -ENOMEM;
+	}
+	kernel_t = &kernel_p->label;
+	root_ns->unconfined->ns = aa_get_ns(root_ns);
+
+	return 0;
+}
+
+ /**
+  * aa_free_root_ns - free the root profile namespace
+  */
+void __init aa_free_root_ns(void)
+{
+	 struct aa_ns *ns = root_ns;
+
+	 root_ns = NULL;
+
+	 aa_label_free(kernel_t);
+	 destroy_ns(ns);
+	 aa_put_ns(ns);
+}