// 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_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);
}
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