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 
21 struct aa_ns;
22 
23 #define LOCAL_VEC_ENTRIES 8
24 #define DEFINE_VEC(T, V)						\
25 	struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES];	\
26 	struct aa_ ## T **(V)
27 
28 #define vec_setup(T, V, N, GFP)						\
29 ({									\
30 	if ((N) <= LOCAL_VEC_ENTRIES) {					\
31 		typeof(N) i;						\
32 		(V) = (_ ## V ## _localtmp);				\
33 		for (i = 0; i < (N); i++)				\
34 			(V)[i] = NULL;					\
35 	} else								\
36 		(V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP));	\
37 	(V) ? 0 : -ENOMEM;						\
38 })
39 
40 #define vec_cleanup(T, V, N)						\
41 do {									\
42 	int i;								\
43 	for (i = 0; i < (N); i++) {					\
44 		if (!IS_ERR_OR_NULL((V)[i]))				\
45 			aa_put_ ## T((V)[i]);				\
46 	}								\
47 	if ((V) != _ ## V ## _localtmp)					\
48 		kfree(V);						\
49 } while (0)
50 
51 #define vec_last(VEC, SIZE) ((VEC)[(SIZE) - 1])
52 #define vec_ns(VEC, SIZE) (vec_last((VEC), (SIZE))->ns)
53 #define vec_labelset(VEC, SIZE) (&vec_ns((VEC), (SIZE))->labels)
54 #define cleanup_domain_vec(V, L) cleanup_label_vec((V), (L)->size)
55 
56 struct aa_profile;
57 #define VEC_FLAG_TERMINATE 1
58 int aa_vec_unique(struct aa_profile **vec, int n, int flags);
59 struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,
60 					     gfp_t gfp);
61 #define aa_sort_and_merge_vec(N, V) \
62 	aa_sort_and_merge_profiles((N), (struct aa_profile **)(V))
63 
64 
65 /* struct aa_labelset - set of labels for a namespace
66  *
67  * Labels are reference counted; aa_labelset does not contribute to label
68  * reference counts. Once a label's last refcount is put it is removed from
69  * the set.
70  */
71 struct aa_labelset {
72 	rwlock_t lock;
73 
74 	struct rb_root root;
75 };
76 
77 #define __labelset_for_each(LS, N) \
78 	for ((N) = rb_first(&(LS)->root); (N); (N) = rb_next(N))
79 
80 enum label_flags {
81 	FLAG_HAT = 1,			/* profile is a hat */
82 	FLAG_UNCONFINED = 2,		/* label unconfined only if all */
83 	FLAG_NULL = 4,			/* profile is null learning profile */
84 	FLAG_IX_ON_NAME_ERROR = 8,	/* fallback to ix on name lookup fail */
85 	FLAG_IMMUTIBLE = 0x10,		/* don't allow changes/replacement */
86 	FLAG_USER_DEFINED = 0x20,	/* user based profile - lower privs */
87 	FLAG_NO_LIST_REF = 0x40,	/* list doesn't keep profile ref */
88 	FLAG_NS_COUNT = 0x80,		/* carries NS ref count */
89 	FLAG_IN_TREE = 0x100,		/* label is in tree */
90 	FLAG_PROFILE = 0x200,		/* label is a profile */
91 	FLAG_EXPLICIT = 0x400,		/* explicit static label */
92 	FLAG_STALE = 0x800,		/* replaced/removed */
93 	FLAG_RENAMED = 0x1000,		/* label has renaming in it */
94 	FLAG_REVOKED = 0x2000,		/* label has revocation in it */
95 	FLAG_DEBUG1 = 0x4000,
96 	FLAG_DEBUG2 = 0x8000,
97 
98 	/* These flags must correspond with PATH_flags */
99 	/* TODO: add new path flags */
100 };
101 
102 struct aa_label;
103 struct aa_proxy {
104 	struct kref count;
105 	struct aa_label __rcu *label;
106 };
107 
108 struct label_it {
109 	int i, j;
110 };
111 
112 /* struct aa_label - lazy labeling struct
113  * @count: ref count of active users
114  * @node: rbtree position
115  * @rcu: rcu callback struct
116  * @proxy: is set to the label that replaced this label
117  * @hname: text representation of the label (MAYBE_NULL)
118  * @flags: stale and other flags - values may change under label set lock
119  * @secid: secid that references this label
120  * @size: number of entries in @ent[]
121  * @ent: set of profiles for label, actual size determined by @size
122  */
123 struct aa_label {
124 	struct kref count;
125 	struct rb_node node;
126 	struct rcu_head rcu;
127 	struct aa_proxy *proxy;
128 	__counted char *hname;
129 	long flags;
130 	u32 secid;
131 	int size;
132 	struct aa_profile *vec[];
133 };
134 
135 #define last_error(E, FN)				\
136 do {							\
137 	int __subE = (FN);				\
138 	if (__subE)					\
139 		(E) = __subE;				\
140 } while (0)
141 
142 #define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
143 #define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
144 #define unconfined(X) label_unconfined(X)
145 #define label_is_stale(X) ((X)->flags & FLAG_STALE)
146 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
147 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
148 #define labels_set(X) (&labels_ns(X)->labels)
149 #define labels_view(X) labels_ns(X)
150 #define labels_profile(X) ((X)->vec[(X)->size - 1])
151 
152 
153 int aa_label_next_confined(struct aa_label *l, int i);
154 
155 /* for each profile in a label */
156 #define label_for_each(I, L, P)						\
157 	for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
158 
159 /* assumes break/goto ended label_for_each */
160 #define label_for_each_cont(I, L, P)					\
161 	for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
162 
163 #define next_comb(I, L1, L2)						\
164 do {									\
165 	(I).j++;							\
166 	if ((I).j >= (L2)->size) {					\
167 		(I).i++;						\
168 		(I).j = 0;						\
169 	}								\
170 } while (0)
171 
172 
173 /* for each combination of P1 in L1, and P2 in L2 */
174 #define label_for_each_comb(I, L1, L2, P1, P2)				\
175 for ((I).i = (I).j = 0;							\
176 	((P1) = (L1)->vec[(I).i]) && ((P2) = (L2)->vec[(I).j]);		\
177 	(I) = next_comb(I, L1, L2))
178 
179 #define fn_for_each_comb(L1, L2, P1, P2, FN)				\
180 ({									\
181 	struct label_it i;						\
182 	int __E = 0;							\
183 	label_for_each_comb(i, (L1), (L2), (P1), (P2)) {		\
184 		last_error(__E, (FN));					\
185 	}								\
186 	__E;								\
187 })
188 
189 /* for each profile that is enforcing confinement in a label */
190 #define label_for_each_confined(I, L, P)				\
191 	for ((I).i = aa_label_next_confined((L), 0);			\
192 	     ((P) = (L)->vec[(I).i]);					\
193 	     (I).i = aa_label_next_confined((L), (I).i + 1))
194 
195 #define label_for_each_in_merge(I, A, B, P)				\
196 	for ((I).i = (I).j = 0;						\
197 	     ((P) = aa_label_next_in_merge(&(I), (A), (B)));		\
198 	     )
199 
200 #define label_for_each_not_in_set(I, SET, SUB, P)			\
201 	for ((I).i = (I).j = 0;						\
202 	     ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));	\
203 	     )
204 
205 #define next_in_ns(i, NS, L)						\
206 ({									\
207 	typeof(i) ___i = (i);						\
208 	while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))		\
209 		(___i)++;						\
210 	(___i);								\
211 })
212 
213 #define label_for_each_in_ns(I, NS, L, P)				\
214 	for ((I).i = next_in_ns(0, (NS), (L));				\
215 	     ((P) = (L)->vec[(I).i]);					\
216 	     (I).i = next_in_ns((I).i + 1, (NS), (L)))
217 
218 #define fn_for_each_in_ns(L, P, FN)					\
219 ({									\
220 	struct label_it __i;						\
221 	struct aa_ns *__ns = labels_ns(L);				\
222 	int __E = 0;							\
223 	label_for_each_in_ns(__i, __ns, (L), (P)) {			\
224 		last_error(__E, (FN));					\
225 	}								\
226 	__E;								\
227 })
228 
229 
230 #define fn_for_each_XXX(L, P, FN, ...)					\
231 ({									\
232 	struct label_it i;						\
233 	int __E = 0;							\
234 	label_for_each ## __VA_ARGS__(i, (L), (P)) {			\
235 		last_error(__E, (FN));					\
236 	}								\
237 	__E;								\
238 })
239 
240 #define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
241 #define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
242 
243 #define fn_for_each2_XXX(L1, L2, P, FN, ...)				\
244 ({									\
245 	struct label_it i;						\
246 	int __E = 0;							\
247 	label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {		\
248 		last_error(__E, (FN));					\
249 	}								\
250 	__E;								\
251 })
252 
253 #define fn_for_each_in_merge(L1, L2, P, FN)				\
254 	fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
255 #define fn_for_each_not_in_set(L1, L2, P, FN)				\
256 	fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
257 
258 #define LABEL_MEDIATES(L, C)						\
259 ({									\
260 	struct aa_profile *profile;					\
261 	struct label_it i;						\
262 	int ret = 0;							\
263 	label_for_each(i, (L), profile) {				\
264 		if (PROFILE_MEDIATES(profile, (C))) {			\
265 			ret = 1;					\
266 			break;						\
267 		}							\
268 	}								\
269 	ret;								\
270 })
271 
272 
273 void aa_labelset_destroy(struct aa_labelset *ls);
274 void aa_labelset_init(struct aa_labelset *ls);
275 void __aa_labelset_update_subtree(struct aa_ns *ns);
276 
277 void aa_label_destroy(struct aa_label *label);
278 void aa_label_free(struct aa_label *label);
279 void aa_label_kref(struct kref *kref);
280 bool aa_label_init(struct aa_label *label, int size, gfp_t gfp);
281 struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
282 
283 bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
284 bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub);
285 struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
286 					     struct aa_label *set,
287 					     struct aa_label *sub);
288 bool aa_label_remove(struct aa_label *label);
289 struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
290 bool aa_label_replace(struct aa_label *old, struct aa_label *new);
291 bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
292 			  struct aa_label *new);
293 
294 struct aa_label *aa_label_find(struct aa_label *l);
295 
296 struct aa_profile *aa_label_next_in_merge(struct label_it *I,
297 					  struct aa_label *a,
298 					  struct aa_label *b);
299 struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
300 struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
301 				gfp_t gfp);
302 
303 
304 bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
305 
306 #define FLAGS_NONE 0
307 #define FLAG_SHOW_MODE 1
308 #define FLAG_VIEW_SUBNS 2
309 #define FLAG_HIDDEN_UNCONFINED 4
310 #define FLAG_ABS_ROOT 8
311 int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
312 		      struct aa_label *label, int flags);
313 int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
314 		      int flags, gfp_t gfp);
315 int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
316 			 struct aa_label *label, int flags, gfp_t gfp);
317 void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
318 		     struct aa_label *label, int flags, gfp_t gfp);
319 void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
320 			 struct aa_label *label, int flags, gfp_t gfp);
321 void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
322 		      gfp_t gfp);
323 void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp);
324 void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp);
325 void aa_label_printk(struct aa_label *label, gfp_t gfp);
326 
327 struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
328 				     size_t n, gfp_t gfp, bool create,
329 				     bool force_stack);
330 struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
331 				gfp_t gfp, bool create, bool force_stack);
332 
aa_label_strn_split(const char * str,int n)333 static inline const char *aa_label_strn_split(const char *str, int n)
334 {
335 	const char *pos;
336 	unsigned int state;
337 
338 	state = aa_dfa_matchn_until(stacksplitdfa, DFA_START, str, n, &pos);
339 	if (!ACCEPT_TABLE(stacksplitdfa)[state])
340 		return NULL;
341 
342 	return pos - 3;
343 }
344 
aa_label_str_split(const char * str)345 static inline const char *aa_label_str_split(const char *str)
346 {
347 	const char *pos;
348 	unsigned int state;
349 
350 	state = aa_dfa_match_until(stacksplitdfa, DFA_START, str, &pos);
351 	if (!ACCEPT_TABLE(stacksplitdfa)[state])
352 		return NULL;
353 
354 	return pos - 3;
355 }
356 
357 
358 
359 struct aa_perms;
360 int aa_label_match(struct aa_profile *profile, struct aa_label *label,
361 		   unsigned int state, bool subns, u32 request,
362 		   struct aa_perms *perms);
363 
364 
365 /**
366  * __aa_get_label - get a reference count to uncounted label reference
367  * @l: reference to get a count on
368  *
369  * Returns: pointer to reference OR NULL if race is lost and reference is
370  *          being repeated.
371  * Requires: lock held, and the return code MUST be checked
372  */
__aa_get_label(struct aa_label * l)373 static inline struct aa_label *__aa_get_label(struct aa_label *l)
374 {
375 	if (l && kref_get_unless_zero(&l->count))
376 		return l;
377 
378 	return NULL;
379 }
380 
aa_get_label(struct aa_label * l)381 static inline struct aa_label *aa_get_label(struct aa_label *l)
382 {
383 	if (l)
384 		kref_get(&(l->count));
385 
386 	return l;
387 }
388 
389 
390 /**
391  * aa_get_label_rcu - increment refcount on a label that can be replaced
392  * @l: pointer to label that can be replaced (NOT NULL)
393  *
394  * Returns: pointer to a refcounted label.
395  *     else NULL if no label
396  */
aa_get_label_rcu(struct aa_label __rcu ** l)397 static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
398 {
399 	struct aa_label *c;
400 
401 	rcu_read_lock();
402 	do {
403 		c = rcu_dereference(*l);
404 	} while (c && !kref_get_unless_zero(&c->count));
405 	rcu_read_unlock();
406 
407 	return c;
408 }
409 
410 /**
411  * aa_get_newest_label - find the newest version of @l
412  * @l: the label to check for newer versions of
413  *
414  * Returns: refcounted newest version of @l taking into account
415  *          replacement, renames and removals
416  *          return @l.
417  */
aa_get_newest_label(struct aa_label * l)418 static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
419 {
420 	if (!l)
421 		return NULL;
422 
423 	if (label_is_stale(l)) {
424 		struct aa_label *tmp;
425 
426 		AA_BUG(!l->proxy);
427 		AA_BUG(!l->proxy->label);
428 		/* BUG: only way this can happen is @l ref count and its
429 		 * replacement count have gone to 0 and are on their way
430 		 * to destruction. ie. we have a refcounting error
431 		 */
432 		tmp = aa_get_label_rcu(&l->proxy->label);
433 		AA_BUG(!tmp);
434 
435 		return tmp;
436 	}
437 
438 	return aa_get_label(l);
439 }
440 
aa_put_label(struct aa_label * l)441 static inline void aa_put_label(struct aa_label *l)
442 {
443 	if (l)
444 		kref_put(&l->count, aa_label_kref);
445 }
446 
447 
448 struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
449 void aa_proxy_kref(struct kref *kref);
450 
aa_get_proxy(struct aa_proxy * proxy)451 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
452 {
453 	if (proxy)
454 		kref_get(&(proxy->count));
455 
456 	return proxy;
457 }
458 
aa_put_proxy(struct aa_proxy * proxy)459 static inline void aa_put_proxy(struct aa_proxy *proxy)
460 {
461 	if (proxy)
462 		kref_put(&proxy->count, aa_proxy_kref);
463 }
464 
465 void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
466 
467 #endif /* __AA_LABEL_H */
468