label.h

  1/* SPDX-License-Identifier: GPL-2.0-only */
  2/*
  3 * AppArmor security module
  4 *
  5 * This file contains AppArmor label definitions
  6 *
  7 * Copyright 2017 Canonical Ltd.
  8 */
  9
 10#ifndef __AA_LABEL_H
 11#define __AA_LABEL_H
 12
 13#include <linux/atomic.h>
 14#include <linux/audit.h>
 15#include <linux/rbtree.h>
 16#include <linux/rcupdate.h>
 17
 18#include "apparmor.h"
 19#include "lib.h"
 20
 21struct aa_ns;
 22struct aa_ruleset;
 23
 24#define LOCAL_VEC_ENTRIES 8
 25#define DEFINE_VEC(T, V)						\
 26	struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES];	\
 27	struct aa_ ## T **(V)
 28
 29#define vec_setup(T, V, N, GFP)						\
 30({									\
 31	if ((N) <= LOCAL_VEC_ENTRIES) {					\
 32		typeof(N) i;						\
 33		(V) = (_ ## V ## _localtmp);				\
 34		for (i = 0; i < (N); i++)				\
 35			(V)[i] = NULL;					\
 36	} else								\
 37		(V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP));	\
 38	(V) ? 0 : -ENOMEM;						\
 39})
 40
 41#define vec_cleanup(T, V, N)						\
 42do {									\
 43	int i;								\
 44	for (i = 0; i < (N); i++) {					\
 45		if (!IS_ERR_OR_NULL((V)[i]))				\
 46			aa_put_ ## T((V)[i]);				\
 47	}								\
 48	if ((V) != _ ## V ## _localtmp)					\
 49		kfree(V);						\
 50} while (0)
 51
 52#define vec_last(VEC, SIZE) ((VEC)[(SIZE) - 1])
 53#define vec_ns(VEC, SIZE) (vec_last((VEC), (SIZE))->ns)
 54#define vec_labelset(VEC, SIZE) (&vec_ns((VEC), (SIZE))->labels)
 55#define cleanup_domain_vec(V, L) cleanup_label_vec((V), (L)->size)
 56
 57struct aa_profile;
 58#define VEC_FLAG_TERMINATE 1
 59int aa_vec_unique(struct aa_profile **vec, int n, int flags);
 60struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,
 61					     gfp_t gfp);
 62#define aa_sort_and_merge_vec(N, V) \
 63	aa_sort_and_merge_profiles((N), (struct aa_profile **)(V))
 64
 65
 66/* struct aa_labelset - set of labels for a namespace
 67 *
 68 * Labels are reference counted; aa_labelset does not contribute to label
 69 * reference counts. Once a label's last refcount is put it is removed from
 70 * the set.
 71 */
 72struct aa_labelset {
 73	rwlock_t lock;
 74
 75	struct rb_root root;
 76};
 77
 78#define __labelset_for_each(LS, N) \
 79	for ((N) = rb_first(&(LS)->root); (N); (N) = rb_next(N))
 80
 81enum label_flags {
 82	FLAG_HAT = 1,			/* profile is a hat */
 83	FLAG_UNCONFINED = 2,		/* label unconfined only if all */
 84	FLAG_NULL = 4,			/* profile is null learning profile */
 85	FLAG_IX_ON_NAME_ERROR = 8,	/* fallback to ix on name lookup fail */
 86	FLAG_IMMUTIBLE = 0x10,		/* don't allow changes/replacement */
 87	FLAG_USER_DEFINED = 0x20,	/* user based profile - lower privs */
 88	FLAG_NO_LIST_REF = 0x40,	/* list doesn't keep profile ref */
 89	FLAG_NS_COUNT = 0x80,		/* carries NS ref count */
 90	FLAG_IN_TREE = 0x100,		/* label is in tree */
 91	FLAG_PROFILE = 0x200,		/* label is a profile */
 92	FLAG_EXPLICIT = 0x400,		/* explicit static label */
 93	FLAG_STALE = 0x800,		/* replaced/removed */
 94	FLAG_RENAMED = 0x1000,		/* label has renaming in it */
 95	FLAG_REVOKED = 0x2000,		/* label has revocation in it */
 96	FLAG_DEBUG1 = 0x4000,
 97	FLAG_DEBUG2 = 0x8000,
 98
 99	/* These flags must correspond with PATH_flags */
100	/* TODO: add new path flags */
101};
102
103struct aa_label;
104struct aa_proxy {
105	struct aa_common_ref count;
106	struct aa_label __rcu *label;
107};
108
109struct label_it {
110	int i, j;
111};
112
113/* struct aa_label_base - base info of label
114 * @count: ref count of active users
115 * @node: rbtree position
116 * @rcu: rcu callback struct
117 * @proxy: is set to the label that replaced this label
118 * @hname: text representation of the label (MAYBE_NULL)
119 * @flags: stale and other flags - values may change under label set lock
120 * @secid: secid that references this label
121 * @size: number of entries in @ent[]
122 * @mediates: bitmask for label_mediates
123 * profile: label vec when embedded in a profile FLAG_PROFILE is set
124 * rules: variable length rules in a profile FLAG_PROFILE is set
125 * vec: vector of profiles comprising the compound label
126 */
127struct aa_label {
128	struct aa_common_ref count;
129	struct rb_node node;
130	struct rcu_head rcu;
131	struct aa_proxy *proxy;
132	__counted char *hname;
133	long flags;
134	u32 secid;
135	int size;
136	u64 mediates;
137	union {
138		struct {
139			/* only used is the label is a profile, size of
140			 * rules[] is determined by the profile
141			 * profile[1] is poison or null as guard
142			 */
143			struct aa_profile *profile[2];
144			DECLARE_FLEX_ARRAY(struct aa_ruleset *, rules);
145		};
146		DECLARE_FLEX_ARRAY(struct aa_profile *, vec);
147	};
148};
149
150#define last_error(E, FN)				\
151do {							\
152	int __subE = (FN);				\
153	if (__subE)					\
154		(E) = __subE;				\
155} while (0)
156
157#define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
158#define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
159#define unconfined(X) label_unconfined(X)
160#define label_is_stale(X) ((X)->flags & FLAG_STALE)
161#define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
162#define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
163#define labels_set(X) (&labels_ns(X)->labels)
164#define labels_view(X) labels_ns(X)
165#define labels_profile(X) ((X)->vec[(X)->size - 1])
166
167
168int aa_label_next_confined(struct aa_label *l, int i);
169
170/* for each profile in a label */
171#define label_for_each(I, L, P)						\
172	for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
173
174/* assumes break/goto ended label_for_each */
175#define label_for_each_cont(I, L, P)					\
176	for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
177
178
179
180/* for each profile that is enforcing confinement in a label */
181#define label_for_each_confined(I, L, P)				\
182	for ((I).i = aa_label_next_confined((L), 0);			\
183	     ((P) = (L)->vec[(I).i]);					\
184	     (I).i = aa_label_next_confined((L), (I).i + 1))
185
186#define label_for_each_in_merge(I, A, B, P)				\
187	for ((I).i = (I).j = 0;						\
188	     ((P) = aa_label_next_in_merge(&(I), (A), (B)));		\
189	     )
190
191#define label_for_each_not_in_set(I, SET, SUB, P)			\
192	for ((I).i = (I).j = 0;						\
193	     ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));	\
194	     )
195
196#define next_in_ns(i, NS, L)						\
197({									\
198	typeof(i) ___i = (i);						\
199	while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))		\
200		(___i)++;						\
201	(___i);								\
202})
203
204#define label_for_each_in_ns(I, NS, L, P)				\
205	for ((I).i = next_in_ns(0, (NS), (L));				\
206	     ((P) = (L)->vec[(I).i]);					\
207	     (I).i = next_in_ns((I).i + 1, (NS), (L)))
208
209#define fn_for_each_in_ns(L, P, FN)					\
210({									\
211	struct label_it __i;						\
212	struct aa_ns *__ns = labels_ns(L);				\
213	int __E = 0;							\
214	label_for_each_in_ns(__i, __ns, (L), (P)) {			\
215		last_error(__E, (FN));					\
216	}								\
217	__E;								\
218})
219
220
221#define fn_for_each_XXX(L, P, FN, ...)					\
222({									\
223	struct label_it i;						\
224	int __E = 0;							\
225	label_for_each ## __VA_ARGS__(i, (L), (P)) {			\
226		last_error(__E, (FN));					\
227	}								\
228	__E;								\
229})
230
231#define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
232#define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
233
234#define fn_for_each2_XXX(L1, L2, P, FN, ...)				\
235({									\
236	struct label_it i;						\
237	int __E = 0;							\
238	label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {		\
239		last_error(__E, (FN));					\
240	}								\
241	__E;								\
242})
243
244#define fn_for_each_in_merge(L1, L2, P, FN)				\
245	fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
246#define fn_for_each_not_in_set(L1, L2, P, FN)				\
247	fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
248
249static inline bool label_mediates(struct aa_label *L, unsigned char C)
250{
251	return (L)->mediates & (((u64) 1) << (C));
252}
253
254static inline bool label_mediates_safe(struct aa_label *L, unsigned char C)
255{
256	if (C > AA_CLASS_LAST)
257		return false;
258	return label_mediates(L, C);
259}
260
261void aa_labelset_destroy(struct aa_labelset *ls);
262void aa_labelset_init(struct aa_labelset *ls);
263void __aa_labelset_update_subtree(struct aa_ns *ns);
264
265void aa_label_destroy(struct aa_label *label);
266void aa_label_free(struct aa_label *label);
267void aa_label_kref(struct kref *kref);
268bool aa_label_init(struct aa_label *label, int size, gfp_t gfp);
269struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
270
271bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
272bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub);
273struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
274					     struct aa_label *set,
275					     struct aa_label *sub);
276bool aa_label_remove(struct aa_label *label);
277struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
278bool aa_label_replace(struct aa_label *old, struct aa_label *new);
279bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
280			  struct aa_label *new);
281
282struct aa_profile *aa_label_next_in_merge(struct label_it *I,
283					  struct aa_label *a,
284					  struct aa_label *b);
285struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
286struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
287				gfp_t gfp);
288
289
290bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
291
292#define FLAGS_NONE 0
293#define FLAG_SHOW_MODE 1
294#define FLAG_VIEW_SUBNS 2
295#define FLAG_HIDDEN_UNCONFINED 4
296#define FLAG_ABS_ROOT 8
297int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
298		      struct aa_label *label, int flags);
299int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
300		      int flags, gfp_t gfp);
301int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
302			 struct aa_label *label, int flags, gfp_t gfp);
303void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
304		     struct aa_label *label, int flags, gfp_t gfp);
305void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
306			 struct aa_label *label, int flags, gfp_t gfp);
307void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
308		      gfp_t gfp);
309void aa_label_printk(struct aa_label *label, gfp_t gfp);
310
311struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
312				     size_t n, gfp_t gfp, bool create,
313				     bool force_stack);
314struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
315				gfp_t gfp, bool create, bool force_stack);
316
317static inline const char *aa_label_strn_split(const char *str, int n)
318{
319	const char *pos;
320	aa_state_t state;
321
322	state = aa_dfa_matchn_until(stacksplitdfa, DFA_START, str, n, &pos);
323	if (!ACCEPT_TABLE(stacksplitdfa)[state])
324		return NULL;
325
326	return pos - 3;
327}
328
329static inline const char *aa_label_str_split(const char *str)
330{
331	const char *pos;
332	aa_state_t state;
333
334	state = aa_dfa_match_until(stacksplitdfa, DFA_START, str, &pos);
335	if (!ACCEPT_TABLE(stacksplitdfa)[state])
336		return NULL;
337
338	return pos - 3;
339}
340
341
342
343struct aa_perms;
344struct aa_ruleset;
345int aa_label_match(struct aa_profile *profile, struct aa_ruleset *rules,
346		   struct aa_label *label, aa_state_t state, bool subns,
347		   u32 request, struct aa_perms *perms);
348
349
350/**
351 * __aa_get_label - get a reference count to uncounted label reference
352 * @l: reference to get a count on
353 *
354 * Returns: pointer to reference OR NULL if race is lost and reference is
355 *          being repeated.
356 * Requires: lock held, and the return code MUST be checked
357 */
358static inline struct aa_label *__aa_get_label(struct aa_label *l)
359{
360	if (l && kref_get_unless_zero(&l->count.count))
361		return l;
362
363	return NULL;
364}
365
366static inline struct aa_label *aa_get_label(struct aa_label *l)
367{
368	if (l)
369		kref_get(&(l->count.count));
370
371	return l;
372}
373
374
375/**
376 * aa_get_label_rcu - increment refcount on a label that can be replaced
377 * @l: pointer to label that can be replaced (NOT NULL)
378 *
379 * Returns: pointer to a refcounted label.
380 *     else NULL if no label
381 */
382static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
383{
384	struct aa_label *c;
385
386	rcu_read_lock();
387	do {
388		c = rcu_dereference(*l);
389	} while (c && !kref_get_unless_zero(&c->count.count));
390	rcu_read_unlock();
391
392	return c;
393}
394
395/**
396 * aa_get_newest_label - find the newest version of @l
397 * @l: the label to check for newer versions of
398 *
399 * Returns: refcounted newest version of @l taking into account
400 *          replacement, renames and removals
401 *          return @l.
402 */
403static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
404{
405	if (!l)
406		return NULL;
407
408	if (label_is_stale(l)) {
409		struct aa_label *tmp;
410
411		AA_BUG(!l->proxy);
412		AA_BUG(!l->proxy->label);
413		/* BUG: only way this can happen is @l ref count and its
414		 * replacement count have gone to 0 and are on their way
415		 * to destruction. ie. we have a refcounting error
416		 */
417		tmp = aa_get_label_rcu(&l->proxy->label);
418		AA_BUG(!tmp);
419
420		return tmp;
421	}
422
423	return aa_get_label(l);
424}
425
426static inline void aa_put_label(struct aa_label *l)
427{
428	if (l)
429		kref_put(&l->count.count, aa_label_kref);
430}
431
432/* wrapper fn to indicate semantics of the check */
433static inline bool __aa_subj_label_is_cached(struct aa_label *subj_label,
434					  struct aa_label *obj_label)
435{
436	return aa_label_is_subset(obj_label, subj_label);
437}
438
439
440struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
441void aa_proxy_kref(struct kref *kref);
442
443static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
444{
445	if (proxy)
446		kref_get(&(proxy->count.count));
447
448	return proxy;
449}
450
451static inline void aa_put_proxy(struct aa_proxy *proxy)
452{
453	if (proxy)
454		kref_put(&proxy->count.count, aa_proxy_kref);
455}
456
457void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
458
459#endif /* __AA_LABEL_H */