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 
96 	/* These flags must correspond with PATH_flags */
97 	/* TODO: add new path flags */
98 };
99 
100 struct aa_label;
101 struct aa_proxy {
102 	struct kref count;
103 	struct aa_label __rcu *label;
104 };
105 
106 struct label_it {
107 	int i, j;
108 };
109 
110 /* struct aa_label - lazy labeling struct
111  * @count: ref count of active users
112  * @node: rbtree position
113  * @rcu: rcu callback struct
114  * @proxy: is set to the label that replaced this label
115  * @hname: text representation of the label (MAYBE_NULL)
116  * @flags: stale and other flags - values may change under label set lock
117  * @secid: secid that references this label
118  * @size: number of entries in @ent[]
119  * @ent: set of profiles for label, actual size determined by @size
120  */
121 struct aa_label {
122 	struct kref count;
123 	struct rb_node node;
124 	struct rcu_head rcu;
125 	struct aa_proxy *proxy;
126 	__counted char *hname;
127 	long flags;
128 	u32 secid;
129 	int size;
130 	struct aa_profile *vec[];
131 };
132 
133 #define last_error(E, FN)				\
134 do {							\
135 	int __subE = (FN);				\
136 	if (__subE)					\
137 		(E) = __subE;				\
138 } while (0)
139 
140 #define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
141 #define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
142 #define unconfined(X) label_unconfined(X)
143 #define label_is_stale(X) ((X)->flags & FLAG_STALE)
144 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
145 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
146 #define labels_set(X) (&labels_ns(X)->labels)
147 #define labels_view(X) labels_ns(X)
148 #define labels_profile(X) ((X)->vec[(X)->size - 1])
149 
150 
151 int aa_label_next_confined(struct aa_label *l, int i);
152 
153 /* for each profile in a label */
154 #define label_for_each(I, L, P)						\
155 	for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
156 
157 /* assumes break/goto ended label_for_each */
158 #define label_for_each_cont(I, L, P)					\
159 	for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
160 
161 #define next_comb(I, L1, L2)						\
162 do {									\
163 	(I).j++;							\
164 	if ((I).j >= (L2)->size) {					\
165 		(I).i++;						\
166 		(I).j = 0;						\
167 	}								\
168 } while (0)
169 
170 
171 /* for each combination of P1 in L1, and P2 in L2 */
172 #define label_for_each_comb(I, L1, L2, P1, P2)				\
173 for ((I).i = (I).j = 0;							\
174 	((P1) = (L1)->vec[(I).i]) && ((P2) = (L2)->vec[(I).j]);		\
175 	(I) = next_comb(I, L1, L2))
176 
177 #define fn_for_each_comb(L1, L2, P1, P2, FN)				\
178 ({									\
179 	struct label_it i;						\
180 	int __E = 0;							\
181 	label_for_each_comb(i, (L1), (L2), (P1), (P2)) {		\
182 		last_error(__E, (FN));					\
183 	}								\
184 	__E;								\
185 })
186 
187 /* for each profile that is enforcing confinement in a label */
188 #define label_for_each_confined(I, L, P)				\
189 	for ((I).i = aa_label_next_confined((L), 0);			\
190 	     ((P) = (L)->vec[(I).i]);					\
191 	     (I).i = aa_label_next_confined((L), (I).i + 1))
192 
193 #define label_for_each_in_merge(I, A, B, P)				\
194 	for ((I).i = (I).j = 0;						\
195 	     ((P) = aa_label_next_in_merge(&(I), (A), (B)));		\
196 	     )
197 
198 #define label_for_each_not_in_set(I, SET, SUB, P)			\
199 	for ((I).i = (I).j = 0;						\
200 	     ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB)));	\
201 	     )
202 
203 #define next_in_ns(i, NS, L)						\
204 ({									\
205 	typeof(i) ___i = (i);						\
206 	while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS))		\
207 		(___i)++;						\
208 	(___i);								\
209 })
210 
211 #define label_for_each_in_ns(I, NS, L, P)				\
212 	for ((I).i = next_in_ns(0, (NS), (L));				\
213 	     ((P) = (L)->vec[(I).i]);					\
214 	     (I).i = next_in_ns((I).i + 1, (NS), (L)))
215 
216 #define fn_for_each_in_ns(L, P, FN)					\
217 ({									\
218 	struct label_it __i;						\
219 	struct aa_ns *__ns = labels_ns(L);				\
220 	int __E = 0;							\
221 	label_for_each_in_ns(__i, __ns, (L), (P)) {			\
222 		last_error(__E, (FN));					\
223 	}								\
224 	__E;								\
225 })
226 
227 
228 #define fn_for_each_XXX(L, P, FN, ...)					\
229 ({									\
230 	struct label_it i;						\
231 	int __E = 0;							\
232 	label_for_each ## __VA_ARGS__(i, (L), (P)) {			\
233 		last_error(__E, (FN));					\
234 	}								\
235 	__E;								\
236 })
237 
238 #define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
239 #define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
240 
241 #define fn_for_each2_XXX(L1, L2, P, FN, ...)				\
242 ({									\
243 	struct label_it i;						\
244 	int __E = 0;							\
245 	label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) {		\
246 		last_error(__E, (FN));					\
247 	}								\
248 	__E;								\
249 })
250 
251 #define fn_for_each_in_merge(L1, L2, P, FN)				\
252 	fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
253 #define fn_for_each_not_in_set(L1, L2, P, FN)				\
254 	fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
255 
256 #define LABEL_MEDIATES(L, C)						\
257 ({									\
258 	struct aa_profile *profile;					\
259 	struct label_it i;						\
260 	int ret = 0;							\
261 	label_for_each(i, (L), profile) {				\
262 		if (PROFILE_MEDIATES(profile, (C))) {			\
263 			ret = 1;					\
264 			break;						\
265 		}							\
266 	}								\
267 	ret;								\
268 })
269 
270 
271 void aa_labelset_destroy(struct aa_labelset *ls);
272 void aa_labelset_init(struct aa_labelset *ls);
273 void __aa_labelset_update_subtree(struct aa_ns *ns);
274 
275 void aa_label_destroy(struct aa_label *label);
276 void aa_label_free(struct aa_label *label);
277 void aa_label_kref(struct kref *kref);
278 bool aa_label_init(struct aa_label *label, int size, gfp_t gfp);
279 struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
280 
281 bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
282 bool aa_label_is_unconfined_subset(struct aa_label *set, struct aa_label *sub);
283 struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
284 					     struct aa_label *set,
285 					     struct aa_label *sub);
286 bool aa_label_remove(struct aa_label *label);
287 struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
288 bool aa_label_replace(struct aa_label *old, struct aa_label *new);
289 bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
290 			  struct aa_label *new);
291 
292 struct aa_label *aa_label_find(struct aa_label *l);
293 
294 struct aa_profile *aa_label_next_in_merge(struct label_it *I,
295 					  struct aa_label *a,
296 					  struct aa_label *b);
297 struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
298 struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
299 				gfp_t gfp);
300 
301 
302 bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
303 
304 #define FLAGS_NONE 0
305 #define FLAG_SHOW_MODE 1
306 #define FLAG_VIEW_SUBNS 2
307 #define FLAG_HIDDEN_UNCONFINED 4
308 #define FLAG_ABS_ROOT 8
309 int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
310 		      struct aa_label *label, int flags);
311 int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
312 		      int flags, gfp_t gfp);
313 int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
314 			 struct aa_label *label, int flags, gfp_t gfp);
315 void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
316 		     struct aa_label *label, int flags, gfp_t gfp);
317 void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
318 			 struct aa_label *label, int flags, gfp_t gfp);
319 void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
320 		      gfp_t gfp);
321 void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp);
322 void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp);
323 void aa_label_printk(struct aa_label *label, gfp_t gfp);
324 
325 struct aa_label *aa_label_strn_parse(struct aa_label *base, const char *str,
326 				     size_t n, gfp_t gfp, bool create,
327 				     bool force_stack);
328 struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
329 				gfp_t gfp, bool create, bool force_stack);
330 
aa_label_strn_split(const char * str,int n)331 static inline const char *aa_label_strn_split(const char *str, int n)
332 {
333 	const char *pos;
334 	unsigned int state;
335 
336 	state = aa_dfa_matchn_until(stacksplitdfa, DFA_START, str, n, &pos);
337 	if (!ACCEPT_TABLE(stacksplitdfa)[state])
338 		return NULL;
339 
340 	return pos - 3;
341 }
342 
aa_label_str_split(const char * str)343 static inline const char *aa_label_str_split(const char *str)
344 {
345 	const char *pos;
346 	unsigned int state;
347 
348 	state = aa_dfa_match_until(stacksplitdfa, DFA_START, str, &pos);
349 	if (!ACCEPT_TABLE(stacksplitdfa)[state])
350 		return NULL;
351 
352 	return pos - 3;
353 }
354 
355 
356 
357 struct aa_perms;
358 int aa_label_match(struct aa_profile *profile, struct aa_label *label,
359 		   unsigned int state, bool subns, u32 request,
360 		   struct aa_perms *perms);
361 
362 
363 /**
364  * __aa_get_label - get a reference count to uncounted label reference
365  * @l: reference to get a count on
366  *
367  * Returns: pointer to reference OR NULL if race is lost and reference is
368  *          being repeated.
369  * Requires: lock held, and the return code MUST be checked
370  */
__aa_get_label(struct aa_label * l)371 static inline struct aa_label *__aa_get_label(struct aa_label *l)
372 {
373 	if (l && kref_get_unless_zero(&l->count))
374 		return l;
375 
376 	return NULL;
377 }
378 
aa_get_label(struct aa_label * l)379 static inline struct aa_label *aa_get_label(struct aa_label *l)
380 {
381 	if (l)
382 		kref_get(&(l->count));
383 
384 	return l;
385 }
386 
387 
388 /**
389  * aa_get_label_rcu - increment refcount on a label that can be replaced
390  * @l: pointer to label that can be replaced (NOT NULL)
391  *
392  * Returns: pointer to a refcounted label.
393  *     else NULL if no label
394  */
aa_get_label_rcu(struct aa_label __rcu ** l)395 static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
396 {
397 	struct aa_label *c;
398 
399 	rcu_read_lock();
400 	do {
401 		c = rcu_dereference(*l);
402 	} while (c && !kref_get_unless_zero(&c->count));
403 	rcu_read_unlock();
404 
405 	return c;
406 }
407 
408 /**
409  * aa_get_newest_label - find the newest version of @l
410  * @l: the label to check for newer versions of
411  *
412  * Returns: refcounted newest version of @l taking into account
413  *          replacement, renames and removals
414  *          return @l.
415  */
aa_get_newest_label(struct aa_label * l)416 static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
417 {
418 	if (!l)
419 		return NULL;
420 
421 	if (label_is_stale(l)) {
422 		struct aa_label *tmp;
423 
424 		AA_BUG(!l->proxy);
425 		AA_BUG(!l->proxy->label);
426 		/* BUG: only way this can happen is @l ref count and its
427 		 * replacement count have gone to 0 and are on their way
428 		 * to destruction. ie. we have a refcounting error
429 		 */
430 		tmp = aa_get_label_rcu(&l->proxy->label);
431 		AA_BUG(!tmp);
432 
433 		return tmp;
434 	}
435 
436 	return aa_get_label(l);
437 }
438 
aa_put_label(struct aa_label * l)439 static inline void aa_put_label(struct aa_label *l)
440 {
441 	if (l)
442 		kref_put(&l->count, aa_label_kref);
443 }
444 
445 
446 struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
447 void aa_proxy_kref(struct kref *kref);
448 
aa_get_proxy(struct aa_proxy * proxy)449 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
450 {
451 	if (proxy)
452 		kref_get(&(proxy->count));
453 
454 	return proxy;
455 }
456 
aa_put_proxy(struct aa_proxy * proxy)457 static inline void aa_put_proxy(struct aa_proxy *proxy)
458 {
459 	if (proxy)
460 		kref_put(&proxy->count, aa_proxy_kref);
461 }
462 
463 void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
464 
465 #endif /* __AA_LABEL_H */
466