diff options
Diffstat (limited to 'security/apparmor/policy_ns.c')
| -rw-r--r-- | security/apparmor/policy_ns.c | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/security/apparmor/policy_ns.c b/security/apparmor/policy_ns.c new file mode 100644 index 000000000..53d24cf63 --- /dev/null +++ b/security/apparmor/policy_ns.c @@ -0,0 +1,410 @@ +// 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" + +/* 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_na_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; +} + +/** + * 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 = aa_alloc_profile("unconfined", NULL, GFP_KERNEL); + if (!ns->unconfined) + goto fail_unconfined; + + ns->unconfined->label.flags |= FLAG_IX_ON_NAME_ERROR | + FLAG_IMMUTIBLE | FLAG_NS_COUNT | FLAG_UNCONFINED; + ns->unconfined->mode = APPARMOR_UNCONFINED; + ns->unconfined->file.dfa = aa_get_dfa(nulldfa); + ns->unconfined->policy.dfa = aa_get_dfa(nulldfa); + + /* 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 + * @base: base list to start looking up profile name from (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_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) +{ + /* released by aa_free_root_ns - used as list ref*/ + root_ns = alloc_ns(NULL, "root"); + if (!root_ns) + return -ENOMEM; + + 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; + + destroy_ns(ns); + aa_put_ns(ns); +} |