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Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * Implementation of the kernel access vector cache (AVC). | |
3 | * | |
7efbb60b | 4 | * Authors: Stephen Smalley, <sds@tycho.nsa.gov> |
95fff33b | 5 | * James Morris <jmorris@redhat.com> |
1da177e4 LT |
6 | * |
7 | * Update: KaiGai, Kohei <kaigai@ak.jp.nec.com> | |
95fff33b | 8 | * Replaced the avc_lock spinlock by RCU. |
1da177e4 LT |
9 | * |
10 | * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License version 2, | |
95fff33b | 14 | * as published by the Free Software Foundation. |
1da177e4 LT |
15 | */ |
16 | #include <linux/types.h> | |
17 | #include <linux/stddef.h> | |
18 | #include <linux/kernel.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/dcache.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/skbuff.h> | |
24 | #include <linux/percpu.h> | |
fa1aa143 | 25 | #include <linux/list.h> |
1da177e4 LT |
26 | #include <net/sock.h> |
27 | #include <linux/un.h> | |
28 | #include <net/af_unix.h> | |
29 | #include <linux/ip.h> | |
30 | #include <linux/audit.h> | |
31 | #include <linux/ipv6.h> | |
32 | #include <net/ipv6.h> | |
33 | #include "avc.h" | |
34 | #include "avc_ss.h" | |
c6d3aaa4 | 35 | #include "classmap.h" |
5c458998 | 36 | |
1da177e4 LT |
37 | #define AVC_CACHE_SLOTS 512 |
38 | #define AVC_DEF_CACHE_THRESHOLD 512 | |
39 | #define AVC_CACHE_RECLAIM 16 | |
40 | ||
41 | #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS | |
044aea9b | 42 | #define avc_cache_stats_incr(field) this_cpu_inc(avc_cache_stats.field) |
1da177e4 LT |
43 | #else |
44 | #define avc_cache_stats_incr(field) do {} while (0) | |
45 | #endif | |
46 | ||
47 | struct avc_entry { | |
48 | u32 ssid; | |
49 | u32 tsid; | |
50 | u16 tclass; | |
51 | struct av_decision avd; | |
fa1aa143 | 52 | struct avc_xperms_node *xp_node; |
1da177e4 LT |
53 | }; |
54 | ||
55 | struct avc_node { | |
56 | struct avc_entry ae; | |
26036651 | 57 | struct hlist_node list; /* anchored in avc_cache->slots[i] */ |
95fff33b | 58 | struct rcu_head rhead; |
1da177e4 LT |
59 | }; |
60 | ||
fa1aa143 JVS |
61 | struct avc_xperms_decision_node { |
62 | struct extended_perms_decision xpd; | |
63 | struct list_head xpd_list; /* list of extended_perms_decision */ | |
64 | }; | |
65 | ||
66 | struct avc_xperms_node { | |
67 | struct extended_perms xp; | |
68 | struct list_head xpd_head; /* list head of extended_perms_decision */ | |
69 | }; | |
70 | ||
1da177e4 | 71 | struct avc_cache { |
26036651 | 72 | struct hlist_head slots[AVC_CACHE_SLOTS]; /* head for avc_node->list */ |
1da177e4 LT |
73 | spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */ |
74 | atomic_t lru_hint; /* LRU hint for reclaim scan */ | |
75 | atomic_t active_nodes; | |
76 | u32 latest_notif; /* latest revocation notification */ | |
77 | }; | |
78 | ||
79 | struct avc_callback_node { | |
562c99f2 | 80 | int (*callback) (u32 event); |
1da177e4 | 81 | u32 events; |
1da177e4 LT |
82 | struct avc_callback_node *next; |
83 | }; | |
84 | ||
1da177e4 LT |
85 | #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS |
86 | DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 }; | |
87 | #endif | |
88 | ||
6b6bc620 SS |
89 | struct selinux_avc { |
90 | unsigned int avc_cache_threshold; | |
91 | struct avc_cache avc_cache; | |
92 | }; | |
93 | ||
94 | static struct selinux_avc selinux_avc; | |
95 | ||
96 | void selinux_avc_init(struct selinux_avc **avc) | |
97 | { | |
98 | int i; | |
99 | ||
100 | selinux_avc.avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD; | |
101 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { | |
102 | INIT_HLIST_HEAD(&selinux_avc.avc_cache.slots[i]); | |
103 | spin_lock_init(&selinux_avc.avc_cache.slots_lock[i]); | |
104 | } | |
105 | atomic_set(&selinux_avc.avc_cache.active_nodes, 0); | |
106 | atomic_set(&selinux_avc.avc_cache.lru_hint, 0); | |
107 | *avc = &selinux_avc; | |
108 | } | |
109 | ||
110 | unsigned int avc_get_cache_threshold(struct selinux_avc *avc) | |
111 | { | |
112 | return avc->avc_cache_threshold; | |
113 | } | |
114 | ||
115 | void avc_set_cache_threshold(struct selinux_avc *avc, | |
116 | unsigned int cache_threshold) | |
117 | { | |
118 | avc->avc_cache_threshold = cache_threshold; | |
119 | } | |
120 | ||
1da177e4 | 121 | static struct avc_callback_node *avc_callbacks; |
e18b890b | 122 | static struct kmem_cache *avc_node_cachep; |
fa1aa143 JVS |
123 | static struct kmem_cache *avc_xperms_data_cachep; |
124 | static struct kmem_cache *avc_xperms_decision_cachep; | |
125 | static struct kmem_cache *avc_xperms_cachep; | |
1da177e4 LT |
126 | |
127 | static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass) | |
128 | { | |
129 | return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1); | |
130 | } | |
131 | ||
132 | /** | |
133 | * avc_dump_av - Display an access vector in human-readable form. | |
134 | * @tclass: target security class | |
135 | * @av: access vector | |
136 | */ | |
44c2d9bd | 137 | static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av) |
1da177e4 | 138 | { |
c6d3aaa4 SS |
139 | const char **perms; |
140 | int i, perm; | |
1da177e4 LT |
141 | |
142 | if (av == 0) { | |
143 | audit_log_format(ab, " null"); | |
144 | return; | |
145 | } | |
146 | ||
bd1741f4 | 147 | BUG_ON(!tclass || tclass >= ARRAY_SIZE(secclass_map)); |
c6d3aaa4 | 148 | perms = secclass_map[tclass-1].perms; |
1da177e4 LT |
149 | |
150 | audit_log_format(ab, " {"); | |
151 | i = 0; | |
152 | perm = 1; | |
c6d3aaa4 | 153 | while (i < (sizeof(av) * 8)) { |
0bce9527 | 154 | if ((perm & av) && perms[i]) { |
c6d3aaa4 | 155 | audit_log_format(ab, " %s", perms[i]); |
1da177e4 LT |
156 | av &= ~perm; |
157 | } | |
158 | i++; | |
159 | perm <<= 1; | |
160 | } | |
161 | ||
1da177e4 LT |
162 | if (av) |
163 | audit_log_format(ab, " 0x%x", av); | |
164 | ||
165 | audit_log_format(ab, " }"); | |
166 | } | |
167 | ||
168 | /** | |
169 | * avc_dump_query - Display a SID pair and a class in human-readable form. | |
170 | * @ssid: source security identifier | |
171 | * @tsid: target security identifier | |
172 | * @tclass: target security class | |
173 | */ | |
6b6bc620 SS |
174 | static void avc_dump_query(struct audit_buffer *ab, struct selinux_state *state, |
175 | u32 ssid, u32 tsid, u16 tclass) | |
1da177e4 LT |
176 | { |
177 | int rc; | |
178 | char *scontext; | |
179 | u32 scontext_len; | |
180 | ||
6b6bc620 | 181 | rc = security_sid_to_context(state, ssid, &scontext, &scontext_len); |
1da177e4 LT |
182 | if (rc) |
183 | audit_log_format(ab, "ssid=%d", ssid); | |
184 | else { | |
185 | audit_log_format(ab, "scontext=%s", scontext); | |
186 | kfree(scontext); | |
187 | } | |
188 | ||
6b6bc620 | 189 | rc = security_sid_to_context(state, tsid, &scontext, &scontext_len); |
1da177e4 LT |
190 | if (rc) |
191 | audit_log_format(ab, " tsid=%d", tsid); | |
192 | else { | |
193 | audit_log_format(ab, " tcontext=%s", scontext); | |
194 | kfree(scontext); | |
195 | } | |
a764ae4b | 196 | |
bd1741f4 | 197 | BUG_ON(!tclass || tclass >= ARRAY_SIZE(secclass_map)); |
c6d3aaa4 | 198 | audit_log_format(ab, " tclass=%s", secclass_map[tclass-1].name); |
1da177e4 LT |
199 | } |
200 | ||
201 | /** | |
202 | * avc_init - Initialize the AVC. | |
203 | * | |
204 | * Initialize the access vector cache. | |
205 | */ | |
206 | void __init avc_init(void) | |
207 | { | |
1da177e4 | 208 | avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node), |
fa1aa143 JVS |
209 | 0, SLAB_PANIC, NULL); |
210 | avc_xperms_cachep = kmem_cache_create("avc_xperms_node", | |
211 | sizeof(struct avc_xperms_node), | |
212 | 0, SLAB_PANIC, NULL); | |
213 | avc_xperms_decision_cachep = kmem_cache_create( | |
214 | "avc_xperms_decision_node", | |
215 | sizeof(struct avc_xperms_decision_node), | |
216 | 0, SLAB_PANIC, NULL); | |
217 | avc_xperms_data_cachep = kmem_cache_create("avc_xperms_data", | |
218 | sizeof(struct extended_perms_data), | |
219 | 0, SLAB_PANIC, NULL); | |
1da177e4 LT |
220 | } |
221 | ||
6b6bc620 | 222 | int avc_get_hash_stats(struct selinux_avc *avc, char *page) |
1da177e4 LT |
223 | { |
224 | int i, chain_len, max_chain_len, slots_used; | |
225 | struct avc_node *node; | |
26036651 | 226 | struct hlist_head *head; |
1da177e4 LT |
227 | |
228 | rcu_read_lock(); | |
229 | ||
230 | slots_used = 0; | |
231 | max_chain_len = 0; | |
232 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { | |
6b6bc620 | 233 | head = &avc->avc_cache.slots[i]; |
26036651 | 234 | if (!hlist_empty(head)) { |
1da177e4 LT |
235 | slots_used++; |
236 | chain_len = 0; | |
b67bfe0d | 237 | hlist_for_each_entry_rcu(node, head, list) |
1da177e4 LT |
238 | chain_len++; |
239 | if (chain_len > max_chain_len) | |
240 | max_chain_len = chain_len; | |
241 | } | |
242 | } | |
243 | ||
244 | rcu_read_unlock(); | |
245 | ||
246 | return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n" | |
247 | "longest chain: %d\n", | |
6b6bc620 | 248 | atomic_read(&avc->avc_cache.active_nodes), |
1da177e4 LT |
249 | slots_used, AVC_CACHE_SLOTS, max_chain_len); |
250 | } | |
251 | ||
fa1aa143 JVS |
252 | /* |
253 | * using a linked list for extended_perms_decision lookup because the list is | |
254 | * always small. i.e. less than 5, typically 1 | |
255 | */ | |
256 | static struct extended_perms_decision *avc_xperms_decision_lookup(u8 driver, | |
257 | struct avc_xperms_node *xp_node) | |
258 | { | |
259 | struct avc_xperms_decision_node *xpd_node; | |
260 | ||
261 | list_for_each_entry(xpd_node, &xp_node->xpd_head, xpd_list) { | |
262 | if (xpd_node->xpd.driver == driver) | |
263 | return &xpd_node->xpd; | |
264 | } | |
265 | return NULL; | |
266 | } | |
267 | ||
268 | static inline unsigned int | |
269 | avc_xperms_has_perm(struct extended_perms_decision *xpd, | |
270 | u8 perm, u8 which) | |
271 | { | |
272 | unsigned int rc = 0; | |
273 | ||
274 | if ((which == XPERMS_ALLOWED) && | |
275 | (xpd->used & XPERMS_ALLOWED)) | |
276 | rc = security_xperm_test(xpd->allowed->p, perm); | |
277 | else if ((which == XPERMS_AUDITALLOW) && | |
278 | (xpd->used & XPERMS_AUDITALLOW)) | |
279 | rc = security_xperm_test(xpd->auditallow->p, perm); | |
280 | else if ((which == XPERMS_DONTAUDIT) && | |
281 | (xpd->used & XPERMS_DONTAUDIT)) | |
282 | rc = security_xperm_test(xpd->dontaudit->p, perm); | |
283 | return rc; | |
284 | } | |
285 | ||
286 | static void avc_xperms_allow_perm(struct avc_xperms_node *xp_node, | |
287 | u8 driver, u8 perm) | |
288 | { | |
289 | struct extended_perms_decision *xpd; | |
290 | security_xperm_set(xp_node->xp.drivers.p, driver); | |
291 | xpd = avc_xperms_decision_lookup(driver, xp_node); | |
292 | if (xpd && xpd->allowed) | |
293 | security_xperm_set(xpd->allowed->p, perm); | |
294 | } | |
295 | ||
296 | static void avc_xperms_decision_free(struct avc_xperms_decision_node *xpd_node) | |
297 | { | |
298 | struct extended_perms_decision *xpd; | |
299 | ||
300 | xpd = &xpd_node->xpd; | |
301 | if (xpd->allowed) | |
302 | kmem_cache_free(avc_xperms_data_cachep, xpd->allowed); | |
303 | if (xpd->auditallow) | |
304 | kmem_cache_free(avc_xperms_data_cachep, xpd->auditallow); | |
305 | if (xpd->dontaudit) | |
306 | kmem_cache_free(avc_xperms_data_cachep, xpd->dontaudit); | |
307 | kmem_cache_free(avc_xperms_decision_cachep, xpd_node); | |
308 | } | |
309 | ||
310 | static void avc_xperms_free(struct avc_xperms_node *xp_node) | |
311 | { | |
312 | struct avc_xperms_decision_node *xpd_node, *tmp; | |
313 | ||
314 | if (!xp_node) | |
315 | return; | |
316 | ||
317 | list_for_each_entry_safe(xpd_node, tmp, &xp_node->xpd_head, xpd_list) { | |
318 | list_del(&xpd_node->xpd_list); | |
319 | avc_xperms_decision_free(xpd_node); | |
320 | } | |
321 | kmem_cache_free(avc_xperms_cachep, xp_node); | |
322 | } | |
323 | ||
324 | static void avc_copy_xperms_decision(struct extended_perms_decision *dest, | |
325 | struct extended_perms_decision *src) | |
326 | { | |
327 | dest->driver = src->driver; | |
328 | dest->used = src->used; | |
329 | if (dest->used & XPERMS_ALLOWED) | |
330 | memcpy(dest->allowed->p, src->allowed->p, | |
331 | sizeof(src->allowed->p)); | |
332 | if (dest->used & XPERMS_AUDITALLOW) | |
333 | memcpy(dest->auditallow->p, src->auditallow->p, | |
334 | sizeof(src->auditallow->p)); | |
335 | if (dest->used & XPERMS_DONTAUDIT) | |
336 | memcpy(dest->dontaudit->p, src->dontaudit->p, | |
337 | sizeof(src->dontaudit->p)); | |
338 | } | |
339 | ||
340 | /* | |
341 | * similar to avc_copy_xperms_decision, but only copy decision | |
342 | * information relevant to this perm | |
343 | */ | |
344 | static inline void avc_quick_copy_xperms_decision(u8 perm, | |
345 | struct extended_perms_decision *dest, | |
346 | struct extended_perms_decision *src) | |
347 | { | |
348 | /* | |
349 | * compute index of the u32 of the 256 bits (8 u32s) that contain this | |
350 | * command permission | |
351 | */ | |
352 | u8 i = perm >> 5; | |
353 | ||
354 | dest->used = src->used; | |
355 | if (dest->used & XPERMS_ALLOWED) | |
356 | dest->allowed->p[i] = src->allowed->p[i]; | |
357 | if (dest->used & XPERMS_AUDITALLOW) | |
358 | dest->auditallow->p[i] = src->auditallow->p[i]; | |
359 | if (dest->used & XPERMS_DONTAUDIT) | |
360 | dest->dontaudit->p[i] = src->dontaudit->p[i]; | |
361 | } | |
362 | ||
363 | static struct avc_xperms_decision_node | |
364 | *avc_xperms_decision_alloc(u8 which) | |
365 | { | |
366 | struct avc_xperms_decision_node *xpd_node; | |
367 | struct extended_perms_decision *xpd; | |
368 | ||
476accbe | 369 | xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, GFP_NOWAIT); |
fa1aa143 JVS |
370 | if (!xpd_node) |
371 | return NULL; | |
372 | ||
373 | xpd = &xpd_node->xpd; | |
374 | if (which & XPERMS_ALLOWED) { | |
375 | xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep, | |
476accbe | 376 | GFP_NOWAIT); |
fa1aa143 JVS |
377 | if (!xpd->allowed) |
378 | goto error; | |
379 | } | |
380 | if (which & XPERMS_AUDITALLOW) { | |
381 | xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep, | |
476accbe | 382 | GFP_NOWAIT); |
fa1aa143 JVS |
383 | if (!xpd->auditallow) |
384 | goto error; | |
385 | } | |
386 | if (which & XPERMS_DONTAUDIT) { | |
387 | xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep, | |
476accbe | 388 | GFP_NOWAIT); |
fa1aa143 JVS |
389 | if (!xpd->dontaudit) |
390 | goto error; | |
391 | } | |
392 | return xpd_node; | |
393 | error: | |
394 | avc_xperms_decision_free(xpd_node); | |
395 | return NULL; | |
396 | } | |
397 | ||
398 | static int avc_add_xperms_decision(struct avc_node *node, | |
399 | struct extended_perms_decision *src) | |
400 | { | |
401 | struct avc_xperms_decision_node *dest_xpd; | |
402 | ||
403 | node->ae.xp_node->xp.len++; | |
404 | dest_xpd = avc_xperms_decision_alloc(src->used); | |
405 | if (!dest_xpd) | |
406 | return -ENOMEM; | |
407 | avc_copy_xperms_decision(&dest_xpd->xpd, src); | |
408 | list_add(&dest_xpd->xpd_list, &node->ae.xp_node->xpd_head); | |
409 | return 0; | |
410 | } | |
411 | ||
412 | static struct avc_xperms_node *avc_xperms_alloc(void) | |
413 | { | |
414 | struct avc_xperms_node *xp_node; | |
415 | ||
476accbe | 416 | xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT); |
fa1aa143 JVS |
417 | if (!xp_node) |
418 | return xp_node; | |
419 | INIT_LIST_HEAD(&xp_node->xpd_head); | |
420 | return xp_node; | |
421 | } | |
422 | ||
423 | static int avc_xperms_populate(struct avc_node *node, | |
424 | struct avc_xperms_node *src) | |
425 | { | |
426 | struct avc_xperms_node *dest; | |
427 | struct avc_xperms_decision_node *dest_xpd; | |
428 | struct avc_xperms_decision_node *src_xpd; | |
429 | ||
430 | if (src->xp.len == 0) | |
431 | return 0; | |
432 | dest = avc_xperms_alloc(); | |
433 | if (!dest) | |
434 | return -ENOMEM; | |
435 | ||
436 | memcpy(dest->xp.drivers.p, src->xp.drivers.p, sizeof(dest->xp.drivers.p)); | |
437 | dest->xp.len = src->xp.len; | |
438 | ||
439 | /* for each source xpd allocate a destination xpd and copy */ | |
440 | list_for_each_entry(src_xpd, &src->xpd_head, xpd_list) { | |
441 | dest_xpd = avc_xperms_decision_alloc(src_xpd->xpd.used); | |
442 | if (!dest_xpd) | |
443 | goto error; | |
444 | avc_copy_xperms_decision(&dest_xpd->xpd, &src_xpd->xpd); | |
445 | list_add(&dest_xpd->xpd_list, &dest->xpd_head); | |
446 | } | |
447 | node->ae.xp_node = dest; | |
448 | return 0; | |
449 | error: | |
450 | avc_xperms_free(dest); | |
451 | return -ENOMEM; | |
452 | ||
453 | } | |
454 | ||
455 | static inline u32 avc_xperms_audit_required(u32 requested, | |
456 | struct av_decision *avd, | |
457 | struct extended_perms_decision *xpd, | |
458 | u8 perm, | |
459 | int result, | |
460 | u32 *deniedp) | |
461 | { | |
462 | u32 denied, audited; | |
463 | ||
464 | denied = requested & ~avd->allowed; | |
465 | if (unlikely(denied)) { | |
466 | audited = denied & avd->auditdeny; | |
467 | if (audited && xpd) { | |
468 | if (avc_xperms_has_perm(xpd, perm, XPERMS_DONTAUDIT)) | |
469 | audited &= ~requested; | |
470 | } | |
471 | } else if (result) { | |
472 | audited = denied = requested; | |
473 | } else { | |
474 | audited = requested & avd->auditallow; | |
475 | if (audited && xpd) { | |
476 | if (!avc_xperms_has_perm(xpd, perm, XPERMS_AUDITALLOW)) | |
477 | audited &= ~requested; | |
478 | } | |
479 | } | |
480 | ||
481 | *deniedp = denied; | |
482 | return audited; | |
483 | } | |
484 | ||
6b6bc620 SS |
485 | static inline int avc_xperms_audit(struct selinux_state *state, |
486 | u32 ssid, u32 tsid, u16 tclass, | |
487 | u32 requested, struct av_decision *avd, | |
488 | struct extended_perms_decision *xpd, | |
489 | u8 perm, int result, | |
490 | struct common_audit_data *ad) | |
fa1aa143 JVS |
491 | { |
492 | u32 audited, denied; | |
493 | ||
494 | audited = avc_xperms_audit_required( | |
495 | requested, avd, xpd, perm, result, &denied); | |
496 | if (likely(!audited)) | |
497 | return 0; | |
6b6bc620 | 498 | return slow_avc_audit(state, ssid, tsid, tclass, requested, |
fa1aa143 JVS |
499 | audited, denied, result, ad, 0); |
500 | } | |
501 | ||
1da177e4 LT |
502 | static void avc_node_free(struct rcu_head *rhead) |
503 | { | |
504 | struct avc_node *node = container_of(rhead, struct avc_node, rhead); | |
fa1aa143 | 505 | avc_xperms_free(node->ae.xp_node); |
1da177e4 LT |
506 | kmem_cache_free(avc_node_cachep, node); |
507 | avc_cache_stats_incr(frees); | |
508 | } | |
509 | ||
6b6bc620 | 510 | static void avc_node_delete(struct selinux_avc *avc, struct avc_node *node) |
1da177e4 | 511 | { |
26036651 | 512 | hlist_del_rcu(&node->list); |
1da177e4 | 513 | call_rcu(&node->rhead, avc_node_free); |
6b6bc620 | 514 | atomic_dec(&avc->avc_cache.active_nodes); |
1da177e4 LT |
515 | } |
516 | ||
6b6bc620 | 517 | static void avc_node_kill(struct selinux_avc *avc, struct avc_node *node) |
1da177e4 | 518 | { |
fa1aa143 | 519 | avc_xperms_free(node->ae.xp_node); |
1da177e4 LT |
520 | kmem_cache_free(avc_node_cachep, node); |
521 | avc_cache_stats_incr(frees); | |
6b6bc620 | 522 | atomic_dec(&avc->avc_cache.active_nodes); |
1da177e4 LT |
523 | } |
524 | ||
6b6bc620 SS |
525 | static void avc_node_replace(struct selinux_avc *avc, |
526 | struct avc_node *new, struct avc_node *old) | |
1da177e4 | 527 | { |
26036651 | 528 | hlist_replace_rcu(&old->list, &new->list); |
1da177e4 | 529 | call_rcu(&old->rhead, avc_node_free); |
6b6bc620 | 530 | atomic_dec(&avc->avc_cache.active_nodes); |
1da177e4 LT |
531 | } |
532 | ||
6b6bc620 | 533 | static inline int avc_reclaim_node(struct selinux_avc *avc) |
1da177e4 LT |
534 | { |
535 | struct avc_node *node; | |
536 | int hvalue, try, ecx; | |
537 | unsigned long flags; | |
26036651 | 538 | struct hlist_head *head; |
edf3d1ae | 539 | spinlock_t *lock; |
1da177e4 | 540 | |
95fff33b | 541 | for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) { |
6b6bc620 SS |
542 | hvalue = atomic_inc_return(&avc->avc_cache.lru_hint) & |
543 | (AVC_CACHE_SLOTS - 1); | |
544 | head = &avc->avc_cache.slots[hvalue]; | |
545 | lock = &avc->avc_cache.slots_lock[hvalue]; | |
1da177e4 | 546 | |
edf3d1ae | 547 | if (!spin_trylock_irqsave(lock, flags)) |
1da177e4 LT |
548 | continue; |
549 | ||
61844250 | 550 | rcu_read_lock(); |
b67bfe0d | 551 | hlist_for_each_entry(node, head, list) { |
6b6bc620 | 552 | avc_node_delete(avc, node); |
906d27d9 EP |
553 | avc_cache_stats_incr(reclaims); |
554 | ecx++; | |
555 | if (ecx >= AVC_CACHE_RECLAIM) { | |
556 | rcu_read_unlock(); | |
edf3d1ae | 557 | spin_unlock_irqrestore(lock, flags); |
906d27d9 | 558 | goto out; |
1da177e4 LT |
559 | } |
560 | } | |
61844250 | 561 | rcu_read_unlock(); |
edf3d1ae | 562 | spin_unlock_irqrestore(lock, flags); |
1da177e4 LT |
563 | } |
564 | out: | |
565 | return ecx; | |
566 | } | |
567 | ||
6b6bc620 | 568 | static struct avc_node *avc_alloc_node(struct selinux_avc *avc) |
1da177e4 LT |
569 | { |
570 | struct avc_node *node; | |
571 | ||
476accbe | 572 | node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT); |
1da177e4 LT |
573 | if (!node) |
574 | goto out; | |
575 | ||
26036651 | 576 | INIT_HLIST_NODE(&node->list); |
1da177e4 LT |
577 | avc_cache_stats_incr(allocations); |
578 | ||
6b6bc620 SS |
579 | if (atomic_inc_return(&avc->avc_cache.active_nodes) > |
580 | avc->avc_cache_threshold) | |
581 | avc_reclaim_node(avc); | |
1da177e4 LT |
582 | |
583 | out: | |
584 | return node; | |
585 | } | |
586 | ||
21193dcd | 587 | static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd) |
1da177e4 LT |
588 | { |
589 | node->ae.ssid = ssid; | |
590 | node->ae.tsid = tsid; | |
591 | node->ae.tclass = tclass; | |
21193dcd | 592 | memcpy(&node->ae.avd, avd, sizeof(node->ae.avd)); |
1da177e4 LT |
593 | } |
594 | ||
6b6bc620 SS |
595 | static inline struct avc_node *avc_search_node(struct selinux_avc *avc, |
596 | u32 ssid, u32 tsid, u16 tclass) | |
1da177e4 LT |
597 | { |
598 | struct avc_node *node, *ret = NULL; | |
599 | int hvalue; | |
26036651 | 600 | struct hlist_head *head; |
1da177e4 LT |
601 | |
602 | hvalue = avc_hash(ssid, tsid, tclass); | |
6b6bc620 | 603 | head = &avc->avc_cache.slots[hvalue]; |
b67bfe0d | 604 | hlist_for_each_entry_rcu(node, head, list) { |
1da177e4 LT |
605 | if (ssid == node->ae.ssid && |
606 | tclass == node->ae.tclass && | |
607 | tsid == node->ae.tsid) { | |
608 | ret = node; | |
609 | break; | |
610 | } | |
611 | } | |
612 | ||
1da177e4 LT |
613 | return ret; |
614 | } | |
615 | ||
616 | /** | |
617 | * avc_lookup - Look up an AVC entry. | |
618 | * @ssid: source security identifier | |
619 | * @tsid: target security identifier | |
620 | * @tclass: target security class | |
1da177e4 LT |
621 | * |
622 | * Look up an AVC entry that is valid for the | |
1da177e4 LT |
623 | * (@ssid, @tsid), interpreting the permissions |
624 | * based on @tclass. If a valid AVC entry exists, | |
6382dc33 | 625 | * then this function returns the avc_node. |
1da177e4 LT |
626 | * Otherwise, this function returns NULL. |
627 | */ | |
6b6bc620 SS |
628 | static struct avc_node *avc_lookup(struct selinux_avc *avc, |
629 | u32 ssid, u32 tsid, u16 tclass) | |
1da177e4 LT |
630 | { |
631 | struct avc_node *node; | |
632 | ||
633 | avc_cache_stats_incr(lookups); | |
6b6bc620 | 634 | node = avc_search_node(avc, ssid, tsid, tclass); |
1da177e4 | 635 | |
f1c6381a | 636 | if (node) |
257313b2 | 637 | return node; |
1da177e4 | 638 | |
257313b2 LT |
639 | avc_cache_stats_incr(misses); |
640 | return NULL; | |
1da177e4 LT |
641 | } |
642 | ||
6b6bc620 SS |
643 | static int avc_latest_notif_update(struct selinux_avc *avc, |
644 | int seqno, int is_insert) | |
1da177e4 LT |
645 | { |
646 | int ret = 0; | |
647 | static DEFINE_SPINLOCK(notif_lock); | |
648 | unsigned long flag; | |
649 | ||
650 | spin_lock_irqsave(¬if_lock, flag); | |
651 | if (is_insert) { | |
6b6bc620 | 652 | if (seqno < avc->avc_cache.latest_notif) { |
744ba35e | 653 | printk(KERN_WARNING "SELinux: avc: seqno %d < latest_notif %d\n", |
6b6bc620 | 654 | seqno, avc->avc_cache.latest_notif); |
1da177e4 LT |
655 | ret = -EAGAIN; |
656 | } | |
657 | } else { | |
6b6bc620 SS |
658 | if (seqno > avc->avc_cache.latest_notif) |
659 | avc->avc_cache.latest_notif = seqno; | |
1da177e4 LT |
660 | } |
661 | spin_unlock_irqrestore(¬if_lock, flag); | |
662 | ||
663 | return ret; | |
664 | } | |
665 | ||
666 | /** | |
667 | * avc_insert - Insert an AVC entry. | |
668 | * @ssid: source security identifier | |
669 | * @tsid: target security identifier | |
670 | * @tclass: target security class | |
21193dcd | 671 | * @avd: resulting av decision |
fa1aa143 | 672 | * @xp_node: resulting extended permissions |
1da177e4 LT |
673 | * |
674 | * Insert an AVC entry for the SID pair | |
675 | * (@ssid, @tsid) and class @tclass. | |
676 | * The access vectors and the sequence number are | |
677 | * normally provided by the security server in | |
678 | * response to a security_compute_av() call. If the | |
21193dcd | 679 | * sequence number @avd->seqno is not less than the latest |
1da177e4 LT |
680 | * revocation notification, then the function copies |
681 | * the access vectors into a cache entry, returns | |
682 | * avc_node inserted. Otherwise, this function returns NULL. | |
683 | */ | |
6b6bc620 SS |
684 | static struct avc_node *avc_insert(struct selinux_avc *avc, |
685 | u32 ssid, u32 tsid, u16 tclass, | |
686 | struct av_decision *avd, | |
687 | struct avc_xperms_node *xp_node) | |
1da177e4 LT |
688 | { |
689 | struct avc_node *pos, *node = NULL; | |
690 | int hvalue; | |
691 | unsigned long flag; | |
692 | ||
6b6bc620 | 693 | if (avc_latest_notif_update(avc, avd->seqno, 1)) |
1da177e4 LT |
694 | goto out; |
695 | ||
6b6bc620 | 696 | node = avc_alloc_node(avc); |
1da177e4 | 697 | if (node) { |
26036651 | 698 | struct hlist_head *head; |
edf3d1ae | 699 | spinlock_t *lock; |
fa1aa143 | 700 | int rc = 0; |
edf3d1ae | 701 | |
1da177e4 | 702 | hvalue = avc_hash(ssid, tsid, tclass); |
21193dcd | 703 | avc_node_populate(node, ssid, tsid, tclass, avd); |
fa1aa143 JVS |
704 | rc = avc_xperms_populate(node, xp_node); |
705 | if (rc) { | |
706 | kmem_cache_free(avc_node_cachep, node); | |
707 | return NULL; | |
708 | } | |
6b6bc620 SS |
709 | head = &avc->avc_cache.slots[hvalue]; |
710 | lock = &avc->avc_cache.slots_lock[hvalue]; | |
edf3d1ae EP |
711 | |
712 | spin_lock_irqsave(lock, flag); | |
b67bfe0d | 713 | hlist_for_each_entry(pos, head, list) { |
1da177e4 LT |
714 | if (pos->ae.ssid == ssid && |
715 | pos->ae.tsid == tsid && | |
716 | pos->ae.tclass == tclass) { | |
6b6bc620 | 717 | avc_node_replace(avc, node, pos); |
1da177e4 LT |
718 | goto found; |
719 | } | |
720 | } | |
26036651 | 721 | hlist_add_head_rcu(&node->list, head); |
1da177e4 | 722 | found: |
edf3d1ae | 723 | spin_unlock_irqrestore(lock, flag); |
1da177e4 LT |
724 | } |
725 | out: | |
726 | return node; | |
727 | } | |
728 | ||
2bf49690 TL |
729 | /** |
730 | * avc_audit_pre_callback - SELinux specific information | |
731 | * will be called by generic audit code | |
732 | * @ab: the audit buffer | |
733 | * @a: audit_data | |
734 | */ | |
735 | static void avc_audit_pre_callback(struct audit_buffer *ab, void *a) | |
1da177e4 | 736 | { |
2bf49690 TL |
737 | struct common_audit_data *ad = a; |
738 | audit_log_format(ab, "avc: %s ", | |
899838b2 EP |
739 | ad->selinux_audit_data->denied ? "denied" : "granted"); |
740 | avc_dump_av(ab, ad->selinux_audit_data->tclass, | |
741 | ad->selinux_audit_data->audited); | |
2bf49690 | 742 | audit_log_format(ab, " for "); |
1da177e4 LT |
743 | } |
744 | ||
2bf49690 TL |
745 | /** |
746 | * avc_audit_post_callback - SELinux specific information | |
747 | * will be called by generic audit code | |
748 | * @ab: the audit buffer | |
749 | * @a: audit_data | |
750 | */ | |
751 | static void avc_audit_post_callback(struct audit_buffer *ab, void *a) | |
1da177e4 | 752 | { |
2bf49690 TL |
753 | struct common_audit_data *ad = a; |
754 | audit_log_format(ab, " "); | |
6b6bc620 SS |
755 | avc_dump_query(ab, ad->selinux_audit_data->state, |
756 | ad->selinux_audit_data->ssid, | |
757 | ad->selinux_audit_data->tsid, | |
758 | ad->selinux_audit_data->tclass); | |
ca7786a2 SS |
759 | if (ad->selinux_audit_data->denied) { |
760 | audit_log_format(ab, " permissive=%u", | |
761 | ad->selinux_audit_data->result ? 0 : 1); | |
762 | } | |
1da177e4 LT |
763 | } |
764 | ||
48aab2f7 | 765 | /* This is the slow part of avc audit with big stack footprint */ |
6b6bc620 SS |
766 | noinline int slow_avc_audit(struct selinux_state *state, |
767 | u32 ssid, u32 tsid, u16 tclass, | |
768 | u32 requested, u32 audited, u32 denied, int result, | |
769 | struct common_audit_data *a, | |
770 | unsigned int flags) | |
48aab2f7 LT |
771 | { |
772 | struct common_audit_data stack_data; | |
899838b2 | 773 | struct selinux_audit_data sad; |
48aab2f7 LT |
774 | |
775 | if (!a) { | |
776 | a = &stack_data; | |
50c205f5 | 777 | a->type = LSM_AUDIT_DATA_NONE; |
48aab2f7 LT |
778 | } |
779 | ||
780 | /* | |
781 | * When in a RCU walk do the audit on the RCU retry. This is because | |
782 | * the collection of the dname in an inode audit message is not RCU | |
783 | * safe. Note this may drop some audits when the situation changes | |
784 | * during retry. However this is logically just as if the operation | |
785 | * happened a little later. | |
786 | */ | |
787 | if ((a->type == LSM_AUDIT_DATA_INODE) && | |
788 | (flags & MAY_NOT_BLOCK)) | |
789 | return -ECHILD; | |
790 | ||
899838b2 EP |
791 | sad.tclass = tclass; |
792 | sad.requested = requested; | |
793 | sad.ssid = ssid; | |
794 | sad.tsid = tsid; | |
795 | sad.audited = audited; | |
796 | sad.denied = denied; | |
ca7786a2 | 797 | sad.result = result; |
6b6bc620 | 798 | sad.state = state; |
899838b2 EP |
799 | |
800 | a->selinux_audit_data = &sad; | |
3f0882c4 | 801 | |
b61c37f5 | 802 | common_lsm_audit(a, avc_audit_pre_callback, avc_audit_post_callback); |
48aab2f7 LT |
803 | return 0; |
804 | } | |
805 | ||
1da177e4 LT |
806 | /** |
807 | * avc_add_callback - Register a callback for security events. | |
808 | * @callback: callback function | |
809 | * @events: security events | |
1da177e4 | 810 | * |
562c99f2 WG |
811 | * Register a callback function for events in the set @events. |
812 | * Returns %0 on success or -%ENOMEM if insufficient memory | |
813 | * exists to add the callback. | |
1da177e4 | 814 | */ |
562c99f2 | 815 | int __init avc_add_callback(int (*callback)(u32 event), u32 events) |
1da177e4 LT |
816 | { |
817 | struct avc_callback_node *c; | |
818 | int rc = 0; | |
819 | ||
0b36e44c | 820 | c = kmalloc(sizeof(*c), GFP_KERNEL); |
1da177e4 LT |
821 | if (!c) { |
822 | rc = -ENOMEM; | |
823 | goto out; | |
824 | } | |
825 | ||
826 | c->callback = callback; | |
827 | c->events = events; | |
1da177e4 LT |
828 | c->next = avc_callbacks; |
829 | avc_callbacks = c; | |
830 | out: | |
831 | return rc; | |
832 | } | |
833 | ||
1da177e4 LT |
834 | /** |
835 | * avc_update_node Update an AVC entry | |
836 | * @event : Updating event | |
837 | * @perms : Permission mask bits | |
838 | * @ssid,@tsid,@tclass : identifier of an AVC entry | |
a5dda683 | 839 | * @seqno : sequence number when decision was made |
fa1aa143 | 840 | * @xpd: extended_perms_decision to be added to the node |
1da177e4 LT |
841 | * |
842 | * if a valid AVC entry doesn't exist,this function returns -ENOENT. | |
843 | * if kmalloc() called internal returns NULL, this function returns -ENOMEM. | |
6382dc33 | 844 | * otherwise, this function updates the AVC entry. The original AVC-entry object |
1da177e4 LT |
845 | * will release later by RCU. |
846 | */ | |
6b6bc620 SS |
847 | static int avc_update_node(struct selinux_avc *avc, |
848 | u32 event, u32 perms, u8 driver, u8 xperm, u32 ssid, | |
849 | u32 tsid, u16 tclass, u32 seqno, | |
850 | struct extended_perms_decision *xpd, | |
851 | u32 flags) | |
1da177e4 LT |
852 | { |
853 | int hvalue, rc = 0; | |
854 | unsigned long flag; | |
855 | struct avc_node *pos, *node, *orig = NULL; | |
26036651 | 856 | struct hlist_head *head; |
edf3d1ae | 857 | spinlock_t *lock; |
1da177e4 | 858 | |
6b6bc620 | 859 | node = avc_alloc_node(avc); |
1da177e4 LT |
860 | if (!node) { |
861 | rc = -ENOMEM; | |
862 | goto out; | |
863 | } | |
864 | ||
865 | /* Lock the target slot */ | |
866 | hvalue = avc_hash(ssid, tsid, tclass); | |
1da177e4 | 867 | |
6b6bc620 SS |
868 | head = &avc->avc_cache.slots[hvalue]; |
869 | lock = &avc->avc_cache.slots_lock[hvalue]; | |
edf3d1ae EP |
870 | |
871 | spin_lock_irqsave(lock, flag); | |
872 | ||
b67bfe0d | 873 | hlist_for_each_entry(pos, head, list) { |
95fff33b EP |
874 | if (ssid == pos->ae.ssid && |
875 | tsid == pos->ae.tsid && | |
a5dda683 EP |
876 | tclass == pos->ae.tclass && |
877 | seqno == pos->ae.avd.seqno){ | |
1da177e4 LT |
878 | orig = pos; |
879 | break; | |
880 | } | |
881 | } | |
882 | ||
883 | if (!orig) { | |
884 | rc = -ENOENT; | |
6b6bc620 | 885 | avc_node_kill(avc, node); |
1da177e4 LT |
886 | goto out_unlock; |
887 | } | |
888 | ||
889 | /* | |
890 | * Copy and replace original node. | |
891 | */ | |
892 | ||
21193dcd | 893 | avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd); |
1da177e4 | 894 | |
fa1aa143 JVS |
895 | if (orig->ae.xp_node) { |
896 | rc = avc_xperms_populate(node, orig->ae.xp_node); | |
897 | if (rc) { | |
898 | kmem_cache_free(avc_node_cachep, node); | |
899 | goto out_unlock; | |
900 | } | |
901 | } | |
902 | ||
1da177e4 LT |
903 | switch (event) { |
904 | case AVC_CALLBACK_GRANT: | |
905 | node->ae.avd.allowed |= perms; | |
fa1aa143 JVS |
906 | if (node->ae.xp_node && (flags & AVC_EXTENDED_PERMS)) |
907 | avc_xperms_allow_perm(node->ae.xp_node, driver, xperm); | |
1da177e4 LT |
908 | break; |
909 | case AVC_CALLBACK_TRY_REVOKE: | |
910 | case AVC_CALLBACK_REVOKE: | |
911 | node->ae.avd.allowed &= ~perms; | |
912 | break; | |
913 | case AVC_CALLBACK_AUDITALLOW_ENABLE: | |
914 | node->ae.avd.auditallow |= perms; | |
915 | break; | |
916 | case AVC_CALLBACK_AUDITALLOW_DISABLE: | |
917 | node->ae.avd.auditallow &= ~perms; | |
918 | break; | |
919 | case AVC_CALLBACK_AUDITDENY_ENABLE: | |
920 | node->ae.avd.auditdeny |= perms; | |
921 | break; | |
922 | case AVC_CALLBACK_AUDITDENY_DISABLE: | |
923 | node->ae.avd.auditdeny &= ~perms; | |
924 | break; | |
fa1aa143 JVS |
925 | case AVC_CALLBACK_ADD_XPERMS: |
926 | avc_add_xperms_decision(node, xpd); | |
927 | break; | |
1da177e4 | 928 | } |
6b6bc620 | 929 | avc_node_replace(avc, node, orig); |
1da177e4 | 930 | out_unlock: |
edf3d1ae | 931 | spin_unlock_irqrestore(lock, flag); |
1da177e4 LT |
932 | out: |
933 | return rc; | |
934 | } | |
935 | ||
936 | /** | |
008574b1 | 937 | * avc_flush - Flush the cache |
1da177e4 | 938 | */ |
6b6bc620 | 939 | static void avc_flush(struct selinux_avc *avc) |
1da177e4 | 940 | { |
26036651 | 941 | struct hlist_head *head; |
008574b1 | 942 | struct avc_node *node; |
edf3d1ae | 943 | spinlock_t *lock; |
008574b1 EP |
944 | unsigned long flag; |
945 | int i; | |
1da177e4 LT |
946 | |
947 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { | |
6b6bc620 SS |
948 | head = &avc->avc_cache.slots[i]; |
949 | lock = &avc->avc_cache.slots_lock[i]; | |
edf3d1ae EP |
950 | |
951 | spin_lock_irqsave(lock, flag); | |
61844250 PM |
952 | /* |
953 | * With preemptable RCU, the outer spinlock does not | |
954 | * prevent RCU grace periods from ending. | |
955 | */ | |
956 | rcu_read_lock(); | |
b67bfe0d | 957 | hlist_for_each_entry(node, head, list) |
6b6bc620 | 958 | avc_node_delete(avc, node); |
61844250 | 959 | rcu_read_unlock(); |
edf3d1ae | 960 | spin_unlock_irqrestore(lock, flag); |
1da177e4 | 961 | } |
008574b1 EP |
962 | } |
963 | ||
964 | /** | |
965 | * avc_ss_reset - Flush the cache and revalidate migrated permissions. | |
966 | * @seqno: policy sequence number | |
967 | */ | |
6b6bc620 | 968 | int avc_ss_reset(struct selinux_avc *avc, u32 seqno) |
008574b1 EP |
969 | { |
970 | struct avc_callback_node *c; | |
971 | int rc = 0, tmprc; | |
972 | ||
6b6bc620 | 973 | avc_flush(avc); |
1da177e4 LT |
974 | |
975 | for (c = avc_callbacks; c; c = c->next) { | |
976 | if (c->events & AVC_CALLBACK_RESET) { | |
562c99f2 | 977 | tmprc = c->callback(AVC_CALLBACK_RESET); |
376bd9cb DG |
978 | /* save the first error encountered for the return |
979 | value and continue processing the callbacks */ | |
980 | if (!rc) | |
981 | rc = tmprc; | |
1da177e4 LT |
982 | } |
983 | } | |
984 | ||
6b6bc620 | 985 | avc_latest_notif_update(avc, seqno, 0); |
1da177e4 LT |
986 | return rc; |
987 | } | |
988 | ||
a554bea8 LT |
989 | /* |
990 | * Slow-path helper function for avc_has_perm_noaudit, | |
991 | * when the avc_node lookup fails. We get called with | |
992 | * the RCU read lock held, and need to return with it | |
993 | * still held, but drop if for the security compute. | |
994 | * | |
995 | * Don't inline this, since it's the slow-path and just | |
996 | * results in a bigger stack frame. | |
997 | */ | |
6b6bc620 SS |
998 | static noinline |
999 | struct avc_node *avc_compute_av(struct selinux_state *state, | |
1000 | u32 ssid, u32 tsid, | |
1001 | u16 tclass, struct av_decision *avd, | |
1002 | struct avc_xperms_node *xp_node) | |
a554bea8 LT |
1003 | { |
1004 | rcu_read_unlock(); | |
fa1aa143 | 1005 | INIT_LIST_HEAD(&xp_node->xpd_head); |
6b6bc620 | 1006 | security_compute_av(state, ssid, tsid, tclass, avd, &xp_node->xp); |
a554bea8 | 1007 | rcu_read_lock(); |
6b6bc620 | 1008 | return avc_insert(state->avc, ssid, tsid, tclass, avd, xp_node); |
a554bea8 LT |
1009 | } |
1010 | ||
6b6bc620 SS |
1011 | static noinline int avc_denied(struct selinux_state *state, |
1012 | u32 ssid, u32 tsid, | |
1013 | u16 tclass, u32 requested, | |
1014 | u8 driver, u8 xperm, unsigned int flags, | |
1015 | struct av_decision *avd) | |
a554bea8 LT |
1016 | { |
1017 | if (flags & AVC_STRICT) | |
1018 | return -EACCES; | |
1019 | ||
6b6bc620 | 1020 | if (enforcing_enabled(state) && |
aa8e712c | 1021 | !(avd->flags & AVD_FLAGS_PERMISSIVE)) |
a554bea8 LT |
1022 | return -EACCES; |
1023 | ||
6b6bc620 SS |
1024 | avc_update_node(state->avc, AVC_CALLBACK_GRANT, requested, driver, |
1025 | xperm, ssid, tsid, tclass, avd->seqno, NULL, flags); | |
a554bea8 LT |
1026 | return 0; |
1027 | } | |
1028 | ||
fa1aa143 JVS |
1029 | /* |
1030 | * The avc extended permissions logic adds an additional 256 bits of | |
1031 | * permissions to an avc node when extended permissions for that node are | |
1032 | * specified in the avtab. If the additional 256 permissions is not adequate, | |
1033 | * as-is the case with ioctls, then multiple may be chained together and the | |
1034 | * driver field is used to specify which set contains the permission. | |
1035 | */ | |
6b6bc620 SS |
1036 | int avc_has_extended_perms(struct selinux_state *state, |
1037 | u32 ssid, u32 tsid, u16 tclass, u32 requested, | |
1038 | u8 driver, u8 xperm, struct common_audit_data *ad) | |
fa1aa143 JVS |
1039 | { |
1040 | struct avc_node *node; | |
1041 | struct av_decision avd; | |
1042 | u32 denied; | |
1043 | struct extended_perms_decision local_xpd; | |
1044 | struct extended_perms_decision *xpd = NULL; | |
1045 | struct extended_perms_data allowed; | |
1046 | struct extended_perms_data auditallow; | |
1047 | struct extended_perms_data dontaudit; | |
1048 | struct avc_xperms_node local_xp_node; | |
1049 | struct avc_xperms_node *xp_node; | |
1050 | int rc = 0, rc2; | |
1051 | ||
1052 | xp_node = &local_xp_node; | |
1053 | BUG_ON(!requested); | |
1054 | ||
1055 | rcu_read_lock(); | |
1056 | ||
6b6bc620 | 1057 | node = avc_lookup(state->avc, ssid, tsid, tclass); |
fa1aa143 | 1058 | if (unlikely(!node)) { |
6b6bc620 | 1059 | node = avc_compute_av(state, ssid, tsid, tclass, &avd, xp_node); |
fa1aa143 JVS |
1060 | } else { |
1061 | memcpy(&avd, &node->ae.avd, sizeof(avd)); | |
1062 | xp_node = node->ae.xp_node; | |
1063 | } | |
1064 | /* if extended permissions are not defined, only consider av_decision */ | |
1065 | if (!xp_node || !xp_node->xp.len) | |
1066 | goto decision; | |
1067 | ||
1068 | local_xpd.allowed = &allowed; | |
1069 | local_xpd.auditallow = &auditallow; | |
1070 | local_xpd.dontaudit = &dontaudit; | |
1071 | ||
1072 | xpd = avc_xperms_decision_lookup(driver, xp_node); | |
1073 | if (unlikely(!xpd)) { | |
1074 | /* | |
1075 | * Compute the extended_perms_decision only if the driver | |
1076 | * is flagged | |
1077 | */ | |
1078 | if (!security_xperm_test(xp_node->xp.drivers.p, driver)) { | |
1079 | avd.allowed &= ~requested; | |
1080 | goto decision; | |
1081 | } | |
1082 | rcu_read_unlock(); | |
6b6bc620 SS |
1083 | security_compute_xperms_decision(state, ssid, tsid, tclass, |
1084 | driver, &local_xpd); | |
fa1aa143 | 1085 | rcu_read_lock(); |
6b6bc620 SS |
1086 | avc_update_node(state->avc, AVC_CALLBACK_ADD_XPERMS, requested, |
1087 | driver, xperm, ssid, tsid, tclass, avd.seqno, | |
1088 | &local_xpd, 0); | |
fa1aa143 JVS |
1089 | } else { |
1090 | avc_quick_copy_xperms_decision(xperm, &local_xpd, xpd); | |
1091 | } | |
1092 | xpd = &local_xpd; | |
1093 | ||
1094 | if (!avc_xperms_has_perm(xpd, xperm, XPERMS_ALLOWED)) | |
1095 | avd.allowed &= ~requested; | |
1096 | ||
1097 | decision: | |
1098 | denied = requested & ~(avd.allowed); | |
1099 | if (unlikely(denied)) | |
6b6bc620 SS |
1100 | rc = avc_denied(state, ssid, tsid, tclass, requested, |
1101 | driver, xperm, AVC_EXTENDED_PERMS, &avd); | |
fa1aa143 JVS |
1102 | |
1103 | rcu_read_unlock(); | |
1104 | ||
6b6bc620 | 1105 | rc2 = avc_xperms_audit(state, ssid, tsid, tclass, requested, |
fa1aa143 JVS |
1106 | &avd, xpd, xperm, rc, ad); |
1107 | if (rc2) | |
1108 | return rc2; | |
1109 | return rc; | |
1110 | } | |
a554bea8 | 1111 | |
1da177e4 LT |
1112 | /** |
1113 | * avc_has_perm_noaudit - Check permissions but perform no auditing. | |
1114 | * @ssid: source security identifier | |
1115 | * @tsid: target security identifier | |
1116 | * @tclass: target security class | |
1117 | * @requested: requested permissions, interpreted based on @tclass | |
2c3c05db | 1118 | * @flags: AVC_STRICT or 0 |
1da177e4 LT |
1119 | * @avd: access vector decisions |
1120 | * | |
1121 | * Check the AVC to determine whether the @requested permissions are granted | |
1122 | * for the SID pair (@ssid, @tsid), interpreting the permissions | |
1123 | * based on @tclass, and call the security server on a cache miss to obtain | |
1124 | * a new decision and add it to the cache. Return a copy of the decisions | |
1125 | * in @avd. Return %0 if all @requested permissions are granted, | |
1126 | * -%EACCES if any permissions are denied, or another -errno upon | |
1127 | * other errors. This function is typically called by avc_has_perm(), | |
1128 | * but may also be called directly to separate permission checking from | |
1129 | * auditing, e.g. in cases where a lock must be held for the check but | |
1130 | * should be released for the auditing. | |
1131 | */ | |
6b6bc620 SS |
1132 | inline int avc_has_perm_noaudit(struct selinux_state *state, |
1133 | u32 ssid, u32 tsid, | |
1134 | u16 tclass, u32 requested, | |
1135 | unsigned int flags, | |
1136 | struct av_decision *avd) | |
1da177e4 LT |
1137 | { |
1138 | struct avc_node *node; | |
fa1aa143 | 1139 | struct avc_xperms_node xp_node; |
1da177e4 LT |
1140 | int rc = 0; |
1141 | u32 denied; | |
1142 | ||
eda4f69c EP |
1143 | BUG_ON(!requested); |
1144 | ||
1da177e4 LT |
1145 | rcu_read_lock(); |
1146 | ||
6b6bc620 | 1147 | node = avc_lookup(state->avc, ssid, tsid, tclass); |
83d4a806 | 1148 | if (unlikely(!node)) |
6b6bc620 | 1149 | node = avc_compute_av(state, ssid, tsid, tclass, avd, &xp_node); |
83d4a806 | 1150 | else |
f01e1af4 | 1151 | memcpy(avd, &node->ae.avd, sizeof(*avd)); |
1da177e4 | 1152 | |
21193dcd | 1153 | denied = requested & ~(avd->allowed); |
a554bea8 | 1154 | if (unlikely(denied)) |
6b6bc620 SS |
1155 | rc = avc_denied(state, ssid, tsid, tclass, requested, 0, 0, |
1156 | flags, avd); | |
1da177e4 LT |
1157 | |
1158 | rcu_read_unlock(); | |
1da177e4 LT |
1159 | return rc; |
1160 | } | |
1161 | ||
1162 | /** | |
1163 | * avc_has_perm - Check permissions and perform any appropriate auditing. | |
1164 | * @ssid: source security identifier | |
1165 | * @tsid: target security identifier | |
1166 | * @tclass: target security class | |
1167 | * @requested: requested permissions, interpreted based on @tclass | |
1168 | * @auditdata: auxiliary audit data | |
1169 | * | |
1170 | * Check the AVC to determine whether the @requested permissions are granted | |
1171 | * for the SID pair (@ssid, @tsid), interpreting the permissions | |
1172 | * based on @tclass, and call the security server on a cache miss to obtain | |
1173 | * a new decision and add it to the cache. Audit the granting or denial of | |
1174 | * permissions in accordance with the policy. Return %0 if all @requested | |
1175 | * permissions are granted, -%EACCES if any permissions are denied, or | |
1176 | * another -errno upon other errors. | |
1177 | */ | |
6b6bc620 | 1178 | int avc_has_perm(struct selinux_state *state, u32 ssid, u32 tsid, u16 tclass, |
cb4fbe57 | 1179 | u32 requested, struct common_audit_data *auditdata) |
1da177e4 LT |
1180 | { |
1181 | struct av_decision avd; | |
9ade0cf4 | 1182 | int rc, rc2; |
1da177e4 | 1183 | |
6b6bc620 SS |
1184 | rc = avc_has_perm_noaudit(state, ssid, tsid, tclass, requested, 0, |
1185 | &avd); | |
9ade0cf4 | 1186 | |
6b6bc620 SS |
1187 | rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc, |
1188 | auditdata, 0); | |
7b20ea25 N |
1189 | if (rc2) |
1190 | return rc2; | |
1191 | return rc; | |
1192 | } | |
1193 | ||
6b6bc620 SS |
1194 | int avc_has_perm_flags(struct selinux_state *state, |
1195 | u32 ssid, u32 tsid, u16 tclass, u32 requested, | |
1196 | struct common_audit_data *auditdata, | |
7b20ea25 N |
1197 | int flags) |
1198 | { | |
1199 | struct av_decision avd; | |
1200 | int rc, rc2; | |
1201 | ||
6b6bc620 SS |
1202 | rc = avc_has_perm_noaudit(state, ssid, tsid, tclass, requested, 0, |
1203 | &avd); | |
7b20ea25 | 1204 | |
6b6bc620 | 1205 | rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc, |
7b20ea25 | 1206 | auditdata, flags); |
9ade0cf4 EP |
1207 | if (rc2) |
1208 | return rc2; | |
1da177e4 LT |
1209 | return rc; |
1210 | } | |
788e7dd4 | 1211 | |
6b6bc620 | 1212 | u32 avc_policy_seqno(struct selinux_state *state) |
788e7dd4 | 1213 | { |
6b6bc620 | 1214 | return state->avc->avc_cache.latest_notif; |
788e7dd4 | 1215 | } |
89c86576 TL |
1216 | |
1217 | void avc_disable(void) | |
1218 | { | |
5224ee08 EP |
1219 | /* |
1220 | * If you are looking at this because you have realized that we are | |
1221 | * not destroying the avc_node_cachep it might be easy to fix, but | |
1222 | * I don't know the memory barrier semantics well enough to know. It's | |
1223 | * possible that some other task dereferenced security_ops when | |
1224 | * it still pointed to selinux operations. If that is the case it's | |
1225 | * possible that it is about to use the avc and is about to need the | |
1226 | * avc_node_cachep. I know I could wrap the security.c security_ops call | |
1227 | * in an rcu_lock, but seriously, it's not worth it. Instead I just flush | |
1228 | * the cache and get that memory back. | |
1229 | */ | |
1230 | if (avc_node_cachep) { | |
6b6bc620 | 1231 | avc_flush(selinux_state.avc); |
5224ee08 EP |
1232 | /* kmem_cache_destroy(avc_node_cachep); */ |
1233 | } | |
89c86576 | 1234 | } |