summaryrefslogtreecommitdiffstats
path: root/security/apparmor/policy_ns.c
blob: 1f02cfe1d974d9a13d8a6c9cff4d9c7a52983c18 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
// 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);
}