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