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1/*
2 * AppArmor security module
3 *
4 * This file contains AppArmor policy manipulation functions
5 *
6 * Copyright (C) 1998-2008 Novell/SUSE
7 * Copyright 2009-2017 Canonical Ltd.
8 *
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License as
11 * published by the Free Software Foundation, version 2 of the
12 * License.
13 *
14 * AppArmor policy namespaces, allow for different sets of policies
15 * to be loaded for tasks within the namespace.
16 */
17
18#include <linux/list.h>
19#include <linux/mutex.h>
20#include <linux/slab.h>
21#include <linux/string.h>
22
23#include "include/apparmor.h"
24#include "include/cred.h"
25#include "include/policy_ns.h"
26#include "include/label.h"
27#include "include/policy.h"
28
29/* root profile namespace */
30struct aa_ns *root_ns;
31const char *aa_hidden_ns_name = "---";
32
33/**
34 * aa_ns_visible - test if @view is visible from @curr
35 * @curr: namespace to treat as the parent (NOT NULL)
36 * @view: namespace to test if visible from @curr (NOT NULL)
37 * @subns: whether view of a subns is allowed
38 *
39 * Returns: true if @view is visible from @curr else false
40 */
41bool aa_ns_visible(struct aa_ns *curr, struct aa_ns *view, bool subns)
42{
43 if (curr == view)
44 return true;
45
46 if (!subns)
47 return false;
48
49 for ( ; view; view = view->parent) {
50 if (view->parent == curr)
51 return true;
52 }
53
54 return false;
55}
56
57/**
58 * aa_na_name - Find the ns name to display for @view from @curr
59 * @curr - current namespace (NOT NULL)
60 * @view - namespace attempting to view (NOT NULL)
61 * @subns - are subns visible
62 *
63 * Returns: name of @view visible from @curr
64 */
65const char *aa_ns_name(struct aa_ns *curr, struct aa_ns *view, bool subns)
66{
67 /* if view == curr then the namespace name isn't displayed */
68 if (curr == view)
69 return "";
70
71 if (aa_ns_visible(curr, view, subns)) {
72 /* at this point if a ns is visible it is in a view ns
73 * thus the curr ns.hname is a prefix of its name.
74 * Only output the virtualized portion of the name
75 * Add + 2 to skip over // separating curr hname prefix
76 * from the visible tail of the views hname
77 */
78 return view->base.hname + strlen(curr->base.hname) + 2;
79 }
80
81 return aa_hidden_ns_name;
82}
83
84/**
85 * alloc_ns - allocate, initialize and return a new namespace
86 * @prefix: parent namespace name (MAYBE NULL)
87 * @name: a preallocated name (NOT NULL)
88 *
89 * Returns: refcounted namespace or NULL on failure.
90 */
91static struct aa_ns *alloc_ns(const char *prefix, const char *name)
92{
93 struct aa_ns *ns;
94
95 ns = kzalloc(sizeof(*ns), GFP_KERNEL);
96 AA_DEBUG("%s(%p)\n", __func__, ns);
97 if (!ns)
98 return NULL;
99 if (!aa_policy_init(&ns->base, prefix, name, GFP_KERNEL))
100 goto fail_ns;
101
102 INIT_LIST_HEAD(&ns->sub_ns);
103 INIT_LIST_HEAD(&ns->rawdata_list);
104 mutex_init(&ns->lock);
105 init_waitqueue_head(&ns->wait);
106
107 /* released by aa_free_ns() */
108 ns->unconfined = aa_alloc_profile("unconfined", NULL, GFP_KERNEL);
109 if (!ns->unconfined)
110 goto fail_unconfined;
111
112 ns->unconfined->label.flags |= FLAG_IX_ON_NAME_ERROR |
113 FLAG_IMMUTIBLE | FLAG_NS_COUNT | FLAG_UNCONFINED;
114 ns->unconfined->mode = APPARMOR_UNCONFINED;
115 ns->unconfined->file.dfa = aa_get_dfa(nulldfa);
116 ns->unconfined->policy.dfa = aa_get_dfa(nulldfa);
117
118 /* ns and ns->unconfined share ns->unconfined refcount */
119 ns->unconfined->ns = ns;
120
121 atomic_set(&ns->uniq_null, 0);
122
123 aa_labelset_init(&ns->labels);
124
125 return ns;
126
127fail_unconfined:
128 kzfree(ns->base.hname);
129fail_ns:
130 kzfree(ns);
131 return NULL;
132}
133
134/**
135 * aa_free_ns - free a profile namespace
136 * @ns: the namespace to free (MAYBE NULL)
137 *
138 * Requires: All references to the namespace must have been put, if the
139 * namespace was referenced by a profile confining a task,
140 */
141void aa_free_ns(struct aa_ns *ns)
142{
143 if (!ns)
144 return;
145
146 aa_policy_destroy(&ns->base);
147 aa_labelset_destroy(&ns->labels);
148 aa_put_ns(ns->parent);
149
150 ns->unconfined->ns = NULL;
151 aa_free_profile(ns->unconfined);
152 kzfree(ns);
153}
154
155/**
156 * aa_findn_ns - look up a profile namespace on the namespace list
157 * @root: namespace to search in (NOT NULL)
158 * @name: name of namespace to find (NOT NULL)
159 * @n: length of @name
160 *
161 * Returns: a refcounted namespace on the list, or NULL if no namespace
162 * called @name exists.
163 *
164 * refcount released by caller
165 */
166struct aa_ns *aa_findn_ns(struct aa_ns *root, const char *name, size_t n)
167{
168 struct aa_ns *ns = NULL;
169
170 rcu_read_lock();
171 ns = aa_get_ns(__aa_findn_ns(&root->sub_ns, name, n));
172 rcu_read_unlock();
173
174 return ns;
175}
176
177/**
178 * aa_find_ns - look up a profile namespace on the namespace list
179 * @root: namespace to search in (NOT NULL)
180 * @name: name of namespace to find (NOT NULL)
181 *
182 * Returns: a refcounted namespace on the list, or NULL if no namespace
183 * called @name exists.
184 *
185 * refcount released by caller
186 */
187struct aa_ns *aa_find_ns(struct aa_ns *root, const char *name)
188{
189 return aa_findn_ns(root, name, strlen(name));
190}
191
192/**
193 * __aa_lookupn_ns - lookup the namespace matching @hname
194 * @base: base list to start looking up profile name from (NOT NULL)
195 * @hname: hierarchical ns name (NOT NULL)
196 * @n: length of @hname
197 *
198 * Requires: rcu_read_lock be held
199 *
200 * Returns: unrefcounted ns pointer or NULL if not found
201 *
202 * Do a relative name lookup, recursing through profile tree.
203 */
204struct aa_ns *__aa_lookupn_ns(struct aa_ns *view, const char *hname, size_t n)
205{
206 struct aa_ns *ns = view;
207 const char *split;
208
209 for (split = strnstr(hname, "//", n); split;
210 split = strnstr(hname, "//", n)) {
211 ns = __aa_findn_ns(&ns->sub_ns, hname, split - hname);
212 if (!ns)
213 return NULL;
214
215 n -= split + 2 - hname;
216 hname = split + 2;
217 }
218
219 if (n)
220 return __aa_findn_ns(&ns->sub_ns, hname, n);
221 return NULL;
222}
223
224/**
225 * aa_lookupn_ns - look up a policy namespace relative to @view
226 * @view: namespace to search in (NOT NULL)
227 * @name: name of namespace to find (NOT NULL)
228 * @n: length of @name
229 *
230 * Returns: a refcounted namespace on the list, or NULL if no namespace
231 * called @name exists.
232 *
233 * refcount released by caller
234 */
235struct aa_ns *aa_lookupn_ns(struct aa_ns *view, const char *name, size_t n)
236{
237 struct aa_ns *ns = NULL;
238
239 rcu_read_lock();
240 ns = aa_get_ns(__aa_lookupn_ns(view, name, n));
241 rcu_read_unlock();
242
243 return ns;
244}
245
246static struct aa_ns *__aa_create_ns(struct aa_ns *parent, const char *name,
247 struct dentry *dir)
248{
249 struct aa_ns *ns;
250 int error;
251
252 AA_BUG(!parent);
253 AA_BUG(!name);
254 AA_BUG(!mutex_is_locked(&parent->lock));
255
256 ns = alloc_ns(parent->base.hname, name);
257 if (!ns)
258 return NULL;
259 ns->level = parent->level + 1;
260 mutex_lock_nested(&ns->lock, ns->level);
261 error = __aafs_ns_mkdir(ns, ns_subns_dir(parent), name, dir);
262 if (error) {
263 AA_ERROR("Failed to create interface for ns %s\n",
264 ns->base.name);
265 mutex_unlock(&ns->lock);
266 aa_free_ns(ns);
267 return ERR_PTR(error);
268 }
269 ns->parent = aa_get_ns(parent);
270 list_add_rcu(&ns->base.list, &parent->sub_ns);
271 /* add list ref */
272 aa_get_ns(ns);
273 mutex_unlock(&ns->lock);
274
275 return ns;
276}
277
278/**
279 * aa_create_ns - create an ns, fail if it already exists
280 * @parent: the parent of the namespace being created
281 * @name: the name of the namespace
282 * @dir: if not null the dir to put the ns entries in
283 *
284 * Returns: the a refcounted ns that has been add or an ERR_PTR
285 */
286struct aa_ns *__aa_find_or_create_ns(struct aa_ns *parent, const char *name,
287 struct dentry *dir)
288{
289 struct aa_ns *ns;
290
291 AA_BUG(!mutex_is_locked(&parent->lock));
292
293 /* try and find the specified ns */
294 /* released by caller */
295 ns = aa_get_ns(__aa_find_ns(&parent->sub_ns, name));
296 if (!ns)
297 ns = __aa_create_ns(parent, name, dir);
298 else
299 ns = ERR_PTR(-EEXIST);
300
301 /* return ref */
302 return ns;
303}
304
305/**
306 * aa_prepare_ns - find an existing or create a new namespace of @name
307 * @parent: ns to treat as parent
308 * @name: the namespace to find or add (NOT NULL)
309 *
310 * Returns: refcounted namespace or PTR_ERR if failed to create one
311 */
312struct aa_ns *aa_prepare_ns(struct aa_ns *parent, const char *name)
313{
314 struct aa_ns *ns;
315
316 mutex_lock_nested(&parent->lock, parent->level);
317 /* try and find the specified ns and if it doesn't exist create it */
318 /* released by caller */
319 ns = aa_get_ns(__aa_find_ns(&parent->sub_ns, name));
320 if (!ns)
321 ns = __aa_create_ns(parent, name, NULL);
322 mutex_unlock(&parent->lock);
323
324 /* return ref */
325 return ns;
326}
327
328static void __ns_list_release(struct list_head *head);
329
330/**
331 * destroy_ns - remove everything contained by @ns
332 * @ns: namespace to have it contents removed (NOT NULL)
333 */
334static void destroy_ns(struct aa_ns *ns)
335{
336 if (!ns)
337 return;
338
339 mutex_lock_nested(&ns->lock, ns->level);
340 /* release all profiles in this namespace */
341 __aa_profile_list_release(&ns->base.profiles);
342
343 /* release all sub namespaces */
344 __ns_list_release(&ns->sub_ns);
345
346 if (ns->parent) {
347 unsigned long flags;
348
349 write_lock_irqsave(&ns->labels.lock, flags);
350 __aa_proxy_redirect(ns_unconfined(ns),
351 ns_unconfined(ns->parent));
352 write_unlock_irqrestore(&ns->labels.lock, flags);
353 }
354 __aafs_ns_rmdir(ns);
355 mutex_unlock(&ns->lock);
356}
357
358/**
359 * __aa_remove_ns - remove a namespace and all its children
360 * @ns: namespace to be removed (NOT NULL)
361 *
362 * Requires: ns->parent->lock be held and ns removed from parent.
363 */
364void __aa_remove_ns(struct aa_ns *ns)
365{
366 /* remove ns from namespace list */
367 list_del_rcu(&ns->base.list);
368 destroy_ns(ns);
369 aa_put_ns(ns);
370}
371
372/**
373 * __ns_list_release - remove all profile namespaces on the list put refs
374 * @head: list of profile namespaces (NOT NULL)
375 *
376 * Requires: namespace lock be held
377 */
378static void __ns_list_release(struct list_head *head)
379{
380 struct aa_ns *ns, *tmp;
381
382 list_for_each_entry_safe(ns, tmp, head, base.list)
383 __aa_remove_ns(ns);
384
385}
386
387/**
388 * aa_alloc_root_ns - allocate the root profile namespace
389 *
390 * Returns: %0 on success else error
391 *
392 */
393int __init aa_alloc_root_ns(void)
394{
395 /* released by aa_free_root_ns - used as list ref*/
396 root_ns = alloc_ns(NULL, "root");
397 if (!root_ns)
398 return -ENOMEM;
399
400 return 0;
401}
402
403 /**
404 * aa_free_root_ns - free the root profile namespace
405 */
406void __init aa_free_root_ns(void)
407{
408 struct aa_ns *ns = root_ns;
409
410 root_ns = NULL;
411
412 destroy_ns(ns);
413 aa_put_ns(ns);
414}