1 /*
2 * AppArmor security module
3 *
4 * This file contains AppArmor label definitions
5 *
6 * Copyright 2017 Canonical Ltd.
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as
10 * published by the Free Software Foundation, version 2 of the
11 * License.
12 */
13
14 #ifndef __AA_LABEL_H
15 #define __AA_LABEL_H
16
17 #include <linux/atomic.h>
18 #include <linux/audit.h>
19 #include <linux/rbtree.h>
20 #include <linux/rcupdate.h>
21
22 #include "apparmor.h"
23 #include "lib.h"
24
25 struct aa_ns;
26
27 #define LOCAL_VEC_ENTRIES 8
28 #define DEFINE_VEC(T, V) \
29 struct aa_ ## T *(_ ## V ## _localtmp)[LOCAL_VEC_ENTRIES]; \
30 struct aa_ ## T **(V)
31
32 #define vec_setup(T, V, N, GFP) \
33 ({ \
34 if ((N) <= LOCAL_VEC_ENTRIES) { \
35 typeof(N) i; \
36 (V) = (_ ## V ## _localtmp); \
37 for (i = 0; i < (N); i++) \
38 (V)[i] = NULL; \
39 } else \
40 (V) = kzalloc(sizeof(struct aa_ ## T *) * (N), (GFP)); \
41 (V) ? 0 : -ENOMEM; \
42 })
43
44 #define vec_cleanup(T, V, N) \
45 do { \
46 int i; \
47 for (i = 0; i < (N); i++) { \
48 if (!IS_ERR_OR_NULL((V)[i])) \
49 aa_put_ ## T((V)[i]); \
50 } \
51 if ((V) != _ ## V ## _localtmp) \
52 kfree(V); \
53 } while (0)
54
55 #define vec_last(VEC, SIZE) ((VEC)[(SIZE) - 1])
56 #define vec_ns(VEC, SIZE) (vec_last((VEC), (SIZE))->ns)
57 #define vec_labelset(VEC, SIZE) (&vec_ns((VEC), (SIZE))->labels)
58 #define cleanup_domain_vec(V, L) cleanup_label_vec((V), (L)->size)
59
60 struct aa_profile;
61 #define VEC_FLAG_TERMINATE 1
62 int aa_vec_unique(struct aa_profile **vec, int n, int flags);
63 struct aa_label *aa_vec_find_or_create_label(struct aa_profile **vec, int len,
64 gfp_t gfp);
65 #define aa_sort_and_merge_vec(N, V) \
66 aa_sort_and_merge_profiles((N), (struct aa_profile **)(V))
67
68
69 /* struct aa_labelset - set of labels for a namespace
70 *
71 * Labels are reference counted; aa_labelset does not contribute to label
72 * reference counts. Once a label's last refcount is put it is removed from
73 * the set.
74 */
75 struct aa_labelset {
76 rwlock_t lock;
77
78 struct rb_root root;
79 };
80
81 #define __labelset_for_each(LS, N) \
82 for ((N) = rb_first(&(LS)->root); (N); (N) = rb_next(N))
83
84 void aa_labelset_destroy(struct aa_labelset *ls);
85 void aa_labelset_init(struct aa_labelset *ls);
86
87
88 enum label_flags {
89 FLAG_HAT = 1, /* profile is a hat */
90 FLAG_UNCONFINED = 2, /* label unconfined only if all */
91 FLAG_NULL = 4, /* profile is null learning profile */
92 FLAG_IX_ON_NAME_ERROR = 8, /* fallback to ix on name lookup fail */
93 FLAG_IMMUTIBLE = 0x10, /* don't allow changes/replacement */
94 FLAG_USER_DEFINED = 0x20, /* user based profile - lower privs */
95 FLAG_NO_LIST_REF = 0x40, /* list doesn't keep profile ref */
96 FLAG_NS_COUNT = 0x80, /* carries NS ref count */
97 FLAG_IN_TREE = 0x100, /* label is in tree */
98 FLAG_PROFILE = 0x200, /* label is a profile */
99 FLAG_EXPLICIT = 0x400, /* explicit static label */
100 FLAG_STALE = 0x800, /* replaced/removed */
101 FLAG_RENAMED = 0x1000, /* label has renaming in it */
102 FLAG_REVOKED = 0x2000, /* label has revocation in it */
103
104 /* These flags must correspond with PATH_flags */
105 /* TODO: add new path flags */
106 };
107
108 struct aa_label;
109 struct aa_proxy {
110 struct kref count;
111 struct aa_label __rcu *label;
112 };
113
114 struct label_it {
115 int i, j;
116 };
117
118 /* struct aa_label - lazy labeling struct
119 * @count: ref count of active users
120 * @node: rbtree position
121 * @rcu: rcu callback struct
122 * @proxy: is set to the label that replaced this label
123 * @hname: text representation of the label (MAYBE_NULL)
124 * @flags: stale and other flags - values may change under label set lock
125 * @secid: secid that references this label
126 * @size: number of entries in @ent[]
127 * @ent: set of profiles for label, actual size determined by @size
128 */
129 struct aa_label {
130 struct kref count;
131 struct rb_node node;
132 struct rcu_head rcu;
133 struct aa_proxy *proxy;
134 __counted char *hname;
135 long flags;
136 u32 secid;
137 int size;
138 struct aa_profile *vec[];
139 };
140
141 #define last_error(E, FN) \
142 do { \
143 int __subE = (FN); \
144 if (__subE) \
145 (E) = __subE; \
146 } while (0)
147
148 #define label_isprofile(X) ((X)->flags & FLAG_PROFILE)
149 #define label_unconfined(X) ((X)->flags & FLAG_UNCONFINED)
150 #define unconfined(X) label_unconfined(X)
151 #define label_is_stale(X) ((X)->flags & FLAG_STALE)
152 #define __label_make_stale(X) ((X)->flags |= FLAG_STALE)
153 #define labels_ns(X) (vec_ns(&((X)->vec[0]), (X)->size))
154 #define labels_set(X) (&labels_ns(X)->labels)
155 #define labels_profile(X) ((X)->vec[(X)->size - 1])
156
157
158 int aa_label_next_confined(struct aa_label *l, int i);
159
160 /* for each profile in a label */
161 #define label_for_each(I, L, P) \
162 for ((I).i = 0; ((P) = (L)->vec[(I).i]); ++((I).i))
163
164 /* assumes break/goto ended label_for_each */
165 #define label_for_each_cont(I, L, P) \
166 for (++((I).i); ((P) = (L)->vec[(I).i]); ++((I).i))
167
168 #define next_comb(I, L1, L2) \
169 do { \
170 (I).j++; \
171 if ((I).j >= (L2)->size) { \
172 (I).i++; \
173 (I).j = 0; \
174 } \
175 } while (0)
176
177
178 /* for each combination of P1 in L1, and P2 in L2 */
179 #define label_for_each_comb(I, L1, L2, P1, P2) \
180 for ((I).i = (I).j = 0; \
181 ((P1) = (L1)->vec[(I).i]) && ((P2) = (L2)->vec[(I).j]); \
182 (I) = next_comb(I, L1, L2))
183
184 #define fn_for_each_comb(L1, L2, P1, P2, FN) \
185 ({ \
186 struct label_it i; \
187 int __E = 0; \
188 label_for_each_comb(i, (L1), (L2), (P1), (P2)) { \
189 last_error(__E, (FN)); \
190 } \
191 __E; \
192 })
193
194 /* for each profile that is enforcing confinement in a label */
195 #define label_for_each_confined(I, L, P) \
196 for ((I).i = aa_label_next_confined((L), 0); \
197 ((P) = (L)->vec[(I).i]); \
198 (I).i = aa_label_next_confined((L), (I).i + 1))
199
200 #define label_for_each_in_merge(I, A, B, P) \
201 for ((I).i = (I).j = 0; \
202 ((P) = aa_label_next_in_merge(&(I), (A), (B))); \
203 )
204
205 #define label_for_each_not_in_set(I, SET, SUB, P) \
206 for ((I).i = (I).j = 0; \
207 ((P) = __aa_label_next_not_in_set(&(I), (SET), (SUB))); \
208 )
209
210 #define next_in_ns(i, NS, L) \
211 ({ \
212 typeof(i) ___i = (i); \
213 while ((L)->vec[___i] && (L)->vec[___i]->ns != (NS)) \
214 (___i)++; \
215 (___i); \
216 })
217
218 #define label_for_each_in_ns(I, NS, L, P) \
219 for ((I).i = next_in_ns(0, (NS), (L)); \
220 ((P) = (L)->vec[(I).i]); \
221 (I).i = next_in_ns((I).i + 1, (NS), (L)))
222
223 #define fn_for_each_in_ns(L, P, FN) \
224 ({ \
225 struct label_it __i; \
226 struct aa_ns *__ns = labels_ns(L); \
227 int __E = 0; \
228 label_for_each_in_ns(__i, __ns, (L), (P)) { \
229 last_error(__E, (FN)); \
230 } \
231 __E; \
232 })
233
234
235 #define fn_for_each_XXX(L, P, FN, ...) \
236 ({ \
237 struct label_it i; \
238 int __E = 0; \
239 label_for_each ## __VA_ARGS__(i, (L), (P)) { \
240 last_error(__E, (FN)); \
241 } \
242 __E; \
243 })
244
245 #define fn_for_each(L, P, FN) fn_for_each_XXX(L, P, FN)
246 #define fn_for_each_confined(L, P, FN) fn_for_each_XXX(L, P, FN, _confined)
247
248 #define fn_for_each2_XXX(L1, L2, P, FN, ...) \
249 ({ \
250 struct label_it i; \
251 int __E = 0; \
252 label_for_each ## __VA_ARGS__(i, (L1), (L2), (P)) { \
253 last_error(__E, (FN)); \
254 } \
255 __E; \
256 })
257
258 #define fn_for_each_in_merge(L1, L2, P, FN) \
259 fn_for_each2_XXX((L1), (L2), P, FN, _in_merge)
260 #define fn_for_each_not_in_set(L1, L2, P, FN) \
261 fn_for_each2_XXX((L1), (L2), P, FN, _not_in_set)
262
263 #define LABEL_MEDIATES(L, C) \
264 ({ \
265 struct aa_profile *profile; \
266 struct label_it i; \
267 int ret = 0; \
268 label_for_each(i, (L), profile) { \
269 if (PROFILE_MEDIATES(profile, (C))) { \
270 ret = 1; \
271 break; \
272 } \
273 } \
274 ret; \
275 })
276
277
278 void aa_labelset_destroy(struct aa_labelset *ls);
279 void aa_labelset_init(struct aa_labelset *ls);
280 void __aa_labelset_update_subtree(struct aa_ns *ns);
281
282 void aa_label_free(struct aa_label *label);
283 void aa_label_kref(struct kref *kref);
284 bool aa_label_init(struct aa_label *label, int size);
285 struct aa_label *aa_label_alloc(int size, struct aa_proxy *proxy, gfp_t gfp);
286
287 bool aa_label_is_subset(struct aa_label *set, struct aa_label *sub);
288 struct aa_profile *__aa_label_next_not_in_set(struct label_it *I,
289 struct aa_label *set,
290 struct aa_label *sub);
291 bool aa_label_remove(struct aa_label *label);
292 struct aa_label *aa_label_insert(struct aa_labelset *ls, struct aa_label *l);
293 bool aa_label_replace(struct aa_label *old, struct aa_label *new);
294 bool aa_label_make_newest(struct aa_labelset *ls, struct aa_label *old,
295 struct aa_label *new);
296
297 struct aa_label *aa_label_find(struct aa_label *l);
298
299 struct aa_profile *aa_label_next_in_merge(struct label_it *I,
300 struct aa_label *a,
301 struct aa_label *b);
302 struct aa_label *aa_label_find_merge(struct aa_label *a, struct aa_label *b);
303 struct aa_label *aa_label_merge(struct aa_label *a, struct aa_label *b,
304 gfp_t gfp);
305
306
307 bool aa_update_label_name(struct aa_ns *ns, struct aa_label *label, gfp_t gfp);
308
309 #define FLAGS_NONE 0
310 #define FLAG_SHOW_MODE 1
311 #define FLAG_VIEW_SUBNS 2
312 #define FLAG_HIDDEN_UNCONFINED 4
313 #define FLAG_ABS_ROOT 8
314 int aa_label_snxprint(char *str, size_t size, struct aa_ns *view,
315 struct aa_label *label, int flags);
316 int aa_label_asxprint(char **strp, struct aa_ns *ns, struct aa_label *label,
317 int flags, gfp_t gfp);
318 int aa_label_acntsxprint(char __counted **strp, struct aa_ns *ns,
319 struct aa_label *label, int flags, gfp_t gfp);
320 void aa_label_xaudit(struct audit_buffer *ab, struct aa_ns *ns,
321 struct aa_label *label, int flags, gfp_t gfp);
322 void aa_label_seq_xprint(struct seq_file *f, struct aa_ns *ns,
323 struct aa_label *label, int flags, gfp_t gfp);
324 void aa_label_xprintk(struct aa_ns *ns, struct aa_label *label, int flags,
325 gfp_t gfp);
326 void aa_label_audit(struct audit_buffer *ab, struct aa_label *label, gfp_t gfp);
327 void aa_label_seq_print(struct seq_file *f, struct aa_label *label, gfp_t gfp);
328 void aa_label_printk(struct aa_label *label, gfp_t gfp);
329
330 struct aa_label *aa_label_parse(struct aa_label *base, const char *str,
331 gfp_t gfp, bool create, bool force_stack);
332
333
334 struct aa_perms;
335 int aa_label_match(struct aa_profile *profile, struct aa_label *label,
336 unsigned int state, bool subns, u32 request,
337 struct aa_perms *perms);
338
339
340 /**
341 * __aa_get_label - get a reference count to uncounted label reference
342 * @l: reference to get a count on
343 *
344 * Returns: pointer to reference OR NULL if race is lost and reference is
345 * being repeated.
346 * Requires: lock held, and the return code MUST be checked
347 */
__aa_get_label(struct aa_label * l)348 static inline struct aa_label *__aa_get_label(struct aa_label *l)
349 {
350 if (l && kref_get_unless_zero(&l->count))
351 return l;
352
353 return NULL;
354 }
355
aa_get_label(struct aa_label * l)356 static inline struct aa_label *aa_get_label(struct aa_label *l)
357 {
358 if (l)
359 kref_get(&(l->count));
360
361 return l;
362 }
363
364
365 /**
366 * aa_get_label_rcu - increment refcount on a label that can be replaced
367 * @l: pointer to label that can be replaced (NOT NULL)
368 *
369 * Returns: pointer to a refcounted label.
370 * else NULL if no label
371 */
aa_get_label_rcu(struct aa_label __rcu ** l)372 static inline struct aa_label *aa_get_label_rcu(struct aa_label __rcu **l)
373 {
374 struct aa_label *c;
375
376 rcu_read_lock();
377 do {
378 c = rcu_dereference(*l);
379 } while (c && !kref_get_unless_zero(&c->count));
380 rcu_read_unlock();
381
382 return c;
383 }
384
385 /**
386 * aa_get_newest_label - find the newest version of @l
387 * @l: the label to check for newer versions of
388 *
389 * Returns: refcounted newest version of @l taking into account
390 * replacement, renames and removals
391 * return @l.
392 */
aa_get_newest_label(struct aa_label * l)393 static inline struct aa_label *aa_get_newest_label(struct aa_label *l)
394 {
395 if (!l)
396 return NULL;
397
398 if (label_is_stale(l)) {
399 struct aa_label *tmp;
400
401 AA_BUG(!l->proxy);
402 AA_BUG(!l->proxy->label);
403 /* BUG: only way this can happen is @l ref count and its
404 * replacement count have gone to 0 and are on their way
405 * to destruction. ie. we have a refcounting error
406 */
407 tmp = aa_get_label_rcu(&l->proxy->label);
408 AA_BUG(!tmp);
409
410 return tmp;
411 }
412
413 return aa_get_label(l);
414 }
415
aa_put_label(struct aa_label * l)416 static inline void aa_put_label(struct aa_label *l)
417 {
418 if (l)
419 kref_put(&l->count, aa_label_kref);
420 }
421
422
423 struct aa_proxy *aa_alloc_proxy(struct aa_label *l, gfp_t gfp);
424 void aa_proxy_kref(struct kref *kref);
425
aa_get_proxy(struct aa_proxy * proxy)426 static inline struct aa_proxy *aa_get_proxy(struct aa_proxy *proxy)
427 {
428 if (proxy)
429 kref_get(&(proxy->count));
430
431 return proxy;
432 }
433
aa_put_proxy(struct aa_proxy * proxy)434 static inline void aa_put_proxy(struct aa_proxy *proxy)
435 {
436 if (proxy)
437 kref_put(&proxy->count, aa_proxy_kref);
438 }
439
440 void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new);
441
442 #endif /* __AA_LABEL_H */
443