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