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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | * Implementation of the kernel access vector cache (AVC). | |
4 | * | |
7efbb60b | 5 | * Authors: Stephen Smalley, <sds@tycho.nsa.gov> |
95fff33b | 6 | * James Morris <jmorris@redhat.com> |
1da177e4 LT |
7 | * |
8 | * Update: KaiGai, Kohei <kaigai@ak.jp.nec.com> | |
95fff33b | 9 | * Replaced the avc_lock spinlock by RCU. |
1da177e4 LT |
10 | * |
11 | * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
1da177e4 LT |
12 | */ |
13 | #include <linux/types.h> | |
14 | #include <linux/stddef.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/fs.h> | |
18 | #include <linux/dcache.h> | |
19 | #include <linux/init.h> | |
20 | #include <linux/skbuff.h> | |
21 | #include <linux/percpu.h> | |
fa1aa143 | 22 | #include <linux/list.h> |
1da177e4 LT |
23 | #include <net/sock.h> |
24 | #include <linux/un.h> | |
25 | #include <net/af_unix.h> | |
26 | #include <linux/ip.h> | |
27 | #include <linux/audit.h> | |
28 | #include <linux/ipv6.h> | |
29 | #include <net/ipv6.h> | |
30 | #include "avc.h" | |
31 | #include "avc_ss.h" | |
c6d3aaa4 | 32 | #include "classmap.h" |
5c458998 | 33 | |
dd816621 TW |
34 | #define CREATE_TRACE_POINTS |
35 | #include <trace/events/avc.h> | |
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 | ||
cd2bb4cb OM |
121 | static struct avc_callback_node *avc_callbacks __ro_after_init; |
122 | static struct kmem_cache *avc_node_cachep __ro_after_init; | |
123 | static struct kmem_cache *avc_xperms_data_cachep __ro_after_init; | |
124 | static struct kmem_cache *avc_xperms_decision_cachep __ro_after_init; | |
125 | static struct kmem_cache *avc_xperms_cachep __ro_after_init; | |
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 | ||
1da177e4 LT |
132 | /** |
133 | * avc_init - Initialize the AVC. | |
134 | * | |
135 | * Initialize the access vector cache. | |
136 | */ | |
137 | void __init avc_init(void) | |
138 | { | |
1da177e4 | 139 | avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node), |
fa1aa143 JVS |
140 | 0, SLAB_PANIC, NULL); |
141 | avc_xperms_cachep = kmem_cache_create("avc_xperms_node", | |
142 | sizeof(struct avc_xperms_node), | |
143 | 0, SLAB_PANIC, NULL); | |
144 | avc_xperms_decision_cachep = kmem_cache_create( | |
145 | "avc_xperms_decision_node", | |
146 | sizeof(struct avc_xperms_decision_node), | |
147 | 0, SLAB_PANIC, NULL); | |
148 | avc_xperms_data_cachep = kmem_cache_create("avc_xperms_data", | |
149 | sizeof(struct extended_perms_data), | |
150 | 0, SLAB_PANIC, NULL); | |
1da177e4 LT |
151 | } |
152 | ||
6b6bc620 | 153 | int avc_get_hash_stats(struct selinux_avc *avc, char *page) |
1da177e4 LT |
154 | { |
155 | int i, chain_len, max_chain_len, slots_used; | |
156 | struct avc_node *node; | |
26036651 | 157 | struct hlist_head *head; |
1da177e4 LT |
158 | |
159 | rcu_read_lock(); | |
160 | ||
161 | slots_used = 0; | |
162 | max_chain_len = 0; | |
163 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { | |
6b6bc620 | 164 | head = &avc->avc_cache.slots[i]; |
26036651 | 165 | if (!hlist_empty(head)) { |
1da177e4 LT |
166 | slots_used++; |
167 | chain_len = 0; | |
b67bfe0d | 168 | hlist_for_each_entry_rcu(node, head, list) |
1da177e4 LT |
169 | chain_len++; |
170 | if (chain_len > max_chain_len) | |
171 | max_chain_len = chain_len; | |
172 | } | |
173 | } | |
174 | ||
175 | rcu_read_unlock(); | |
176 | ||
177 | return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n" | |
178 | "longest chain: %d\n", | |
6b6bc620 | 179 | atomic_read(&avc->avc_cache.active_nodes), |
1da177e4 LT |
180 | slots_used, AVC_CACHE_SLOTS, max_chain_len); |
181 | } | |
182 | ||
fa1aa143 JVS |
183 | /* |
184 | * using a linked list for extended_perms_decision lookup because the list is | |
185 | * always small. i.e. less than 5, typically 1 | |
186 | */ | |
187 | static struct extended_perms_decision *avc_xperms_decision_lookup(u8 driver, | |
188 | struct avc_xperms_node *xp_node) | |
189 | { | |
190 | struct avc_xperms_decision_node *xpd_node; | |
191 | ||
192 | list_for_each_entry(xpd_node, &xp_node->xpd_head, xpd_list) { | |
193 | if (xpd_node->xpd.driver == driver) | |
194 | return &xpd_node->xpd; | |
195 | } | |
196 | return NULL; | |
197 | } | |
198 | ||
199 | static inline unsigned int | |
200 | avc_xperms_has_perm(struct extended_perms_decision *xpd, | |
201 | u8 perm, u8 which) | |
202 | { | |
203 | unsigned int rc = 0; | |
204 | ||
205 | if ((which == XPERMS_ALLOWED) && | |
206 | (xpd->used & XPERMS_ALLOWED)) | |
207 | rc = security_xperm_test(xpd->allowed->p, perm); | |
208 | else if ((which == XPERMS_AUDITALLOW) && | |
209 | (xpd->used & XPERMS_AUDITALLOW)) | |
210 | rc = security_xperm_test(xpd->auditallow->p, perm); | |
211 | else if ((which == XPERMS_DONTAUDIT) && | |
212 | (xpd->used & XPERMS_DONTAUDIT)) | |
213 | rc = security_xperm_test(xpd->dontaudit->p, perm); | |
214 | return rc; | |
215 | } | |
216 | ||
217 | static void avc_xperms_allow_perm(struct avc_xperms_node *xp_node, | |
218 | u8 driver, u8 perm) | |
219 | { | |
220 | struct extended_perms_decision *xpd; | |
221 | security_xperm_set(xp_node->xp.drivers.p, driver); | |
222 | xpd = avc_xperms_decision_lookup(driver, xp_node); | |
223 | if (xpd && xpd->allowed) | |
224 | security_xperm_set(xpd->allowed->p, perm); | |
225 | } | |
226 | ||
227 | static void avc_xperms_decision_free(struct avc_xperms_decision_node *xpd_node) | |
228 | { | |
229 | struct extended_perms_decision *xpd; | |
230 | ||
231 | xpd = &xpd_node->xpd; | |
232 | if (xpd->allowed) | |
233 | kmem_cache_free(avc_xperms_data_cachep, xpd->allowed); | |
234 | if (xpd->auditallow) | |
235 | kmem_cache_free(avc_xperms_data_cachep, xpd->auditallow); | |
236 | if (xpd->dontaudit) | |
237 | kmem_cache_free(avc_xperms_data_cachep, xpd->dontaudit); | |
238 | kmem_cache_free(avc_xperms_decision_cachep, xpd_node); | |
239 | } | |
240 | ||
241 | static void avc_xperms_free(struct avc_xperms_node *xp_node) | |
242 | { | |
243 | struct avc_xperms_decision_node *xpd_node, *tmp; | |
244 | ||
245 | if (!xp_node) | |
246 | return; | |
247 | ||
248 | list_for_each_entry_safe(xpd_node, tmp, &xp_node->xpd_head, xpd_list) { | |
249 | list_del(&xpd_node->xpd_list); | |
250 | avc_xperms_decision_free(xpd_node); | |
251 | } | |
252 | kmem_cache_free(avc_xperms_cachep, xp_node); | |
253 | } | |
254 | ||
255 | static void avc_copy_xperms_decision(struct extended_perms_decision *dest, | |
256 | struct extended_perms_decision *src) | |
257 | { | |
258 | dest->driver = src->driver; | |
259 | dest->used = src->used; | |
260 | if (dest->used & XPERMS_ALLOWED) | |
261 | memcpy(dest->allowed->p, src->allowed->p, | |
262 | sizeof(src->allowed->p)); | |
263 | if (dest->used & XPERMS_AUDITALLOW) | |
264 | memcpy(dest->auditallow->p, src->auditallow->p, | |
265 | sizeof(src->auditallow->p)); | |
266 | if (dest->used & XPERMS_DONTAUDIT) | |
267 | memcpy(dest->dontaudit->p, src->dontaudit->p, | |
268 | sizeof(src->dontaudit->p)); | |
269 | } | |
270 | ||
271 | /* | |
272 | * similar to avc_copy_xperms_decision, but only copy decision | |
273 | * information relevant to this perm | |
274 | */ | |
275 | static inline void avc_quick_copy_xperms_decision(u8 perm, | |
276 | struct extended_perms_decision *dest, | |
277 | struct extended_perms_decision *src) | |
278 | { | |
279 | /* | |
280 | * compute index of the u32 of the 256 bits (8 u32s) that contain this | |
281 | * command permission | |
282 | */ | |
283 | u8 i = perm >> 5; | |
284 | ||
285 | dest->used = src->used; | |
286 | if (dest->used & XPERMS_ALLOWED) | |
287 | dest->allowed->p[i] = src->allowed->p[i]; | |
288 | if (dest->used & XPERMS_AUDITALLOW) | |
289 | dest->auditallow->p[i] = src->auditallow->p[i]; | |
290 | if (dest->used & XPERMS_DONTAUDIT) | |
291 | dest->dontaudit->p[i] = src->dontaudit->p[i]; | |
292 | } | |
293 | ||
294 | static struct avc_xperms_decision_node | |
295 | *avc_xperms_decision_alloc(u8 which) | |
296 | { | |
297 | struct avc_xperms_decision_node *xpd_node; | |
298 | struct extended_perms_decision *xpd; | |
299 | ||
648f2c61 MK |
300 | xpd_node = kmem_cache_zalloc(avc_xperms_decision_cachep, |
301 | GFP_NOWAIT | __GFP_NOWARN); | |
fa1aa143 JVS |
302 | if (!xpd_node) |
303 | return NULL; | |
304 | ||
305 | xpd = &xpd_node->xpd; | |
306 | if (which & XPERMS_ALLOWED) { | |
307 | xpd->allowed = kmem_cache_zalloc(avc_xperms_data_cachep, | |
648f2c61 | 308 | GFP_NOWAIT | __GFP_NOWARN); |
fa1aa143 JVS |
309 | if (!xpd->allowed) |
310 | goto error; | |
311 | } | |
312 | if (which & XPERMS_AUDITALLOW) { | |
313 | xpd->auditallow = kmem_cache_zalloc(avc_xperms_data_cachep, | |
648f2c61 | 314 | GFP_NOWAIT | __GFP_NOWARN); |
fa1aa143 JVS |
315 | if (!xpd->auditallow) |
316 | goto error; | |
317 | } | |
318 | if (which & XPERMS_DONTAUDIT) { | |
319 | xpd->dontaudit = kmem_cache_zalloc(avc_xperms_data_cachep, | |
648f2c61 | 320 | GFP_NOWAIT | __GFP_NOWARN); |
fa1aa143 JVS |
321 | if (!xpd->dontaudit) |
322 | goto error; | |
323 | } | |
324 | return xpd_node; | |
325 | error: | |
326 | avc_xperms_decision_free(xpd_node); | |
327 | return NULL; | |
328 | } | |
329 | ||
330 | static int avc_add_xperms_decision(struct avc_node *node, | |
331 | struct extended_perms_decision *src) | |
332 | { | |
333 | struct avc_xperms_decision_node *dest_xpd; | |
334 | ||
335 | node->ae.xp_node->xp.len++; | |
336 | dest_xpd = avc_xperms_decision_alloc(src->used); | |
337 | if (!dest_xpd) | |
338 | return -ENOMEM; | |
339 | avc_copy_xperms_decision(&dest_xpd->xpd, src); | |
340 | list_add(&dest_xpd->xpd_list, &node->ae.xp_node->xpd_head); | |
341 | return 0; | |
342 | } | |
343 | ||
344 | static struct avc_xperms_node *avc_xperms_alloc(void) | |
345 | { | |
346 | struct avc_xperms_node *xp_node; | |
347 | ||
648f2c61 | 348 | xp_node = kmem_cache_zalloc(avc_xperms_cachep, GFP_NOWAIT | __GFP_NOWARN); |
fa1aa143 JVS |
349 | if (!xp_node) |
350 | return xp_node; | |
351 | INIT_LIST_HEAD(&xp_node->xpd_head); | |
352 | return xp_node; | |
353 | } | |
354 | ||
355 | static int avc_xperms_populate(struct avc_node *node, | |
356 | struct avc_xperms_node *src) | |
357 | { | |
358 | struct avc_xperms_node *dest; | |
359 | struct avc_xperms_decision_node *dest_xpd; | |
360 | struct avc_xperms_decision_node *src_xpd; | |
361 | ||
362 | if (src->xp.len == 0) | |
363 | return 0; | |
364 | dest = avc_xperms_alloc(); | |
365 | if (!dest) | |
366 | return -ENOMEM; | |
367 | ||
368 | memcpy(dest->xp.drivers.p, src->xp.drivers.p, sizeof(dest->xp.drivers.p)); | |
369 | dest->xp.len = src->xp.len; | |
370 | ||
371 | /* for each source xpd allocate a destination xpd and copy */ | |
372 | list_for_each_entry(src_xpd, &src->xpd_head, xpd_list) { | |
373 | dest_xpd = avc_xperms_decision_alloc(src_xpd->xpd.used); | |
374 | if (!dest_xpd) | |
375 | goto error; | |
376 | avc_copy_xperms_decision(&dest_xpd->xpd, &src_xpd->xpd); | |
377 | list_add(&dest_xpd->xpd_list, &dest->xpd_head); | |
378 | } | |
379 | node->ae.xp_node = dest; | |
380 | return 0; | |
381 | error: | |
382 | avc_xperms_free(dest); | |
383 | return -ENOMEM; | |
384 | ||
385 | } | |
386 | ||
387 | static inline u32 avc_xperms_audit_required(u32 requested, | |
388 | struct av_decision *avd, | |
389 | struct extended_perms_decision *xpd, | |
390 | u8 perm, | |
391 | int result, | |
392 | u32 *deniedp) | |
393 | { | |
394 | u32 denied, audited; | |
395 | ||
396 | denied = requested & ~avd->allowed; | |
397 | if (unlikely(denied)) { | |
398 | audited = denied & avd->auditdeny; | |
399 | if (audited && xpd) { | |
400 | if (avc_xperms_has_perm(xpd, perm, XPERMS_DONTAUDIT)) | |
401 | audited &= ~requested; | |
402 | } | |
403 | } else if (result) { | |
404 | audited = denied = requested; | |
405 | } else { | |
406 | audited = requested & avd->auditallow; | |
407 | if (audited && xpd) { | |
408 | if (!avc_xperms_has_perm(xpd, perm, XPERMS_AUDITALLOW)) | |
409 | audited &= ~requested; | |
410 | } | |
411 | } | |
412 | ||
413 | *deniedp = denied; | |
414 | return audited; | |
415 | } | |
416 | ||
6b6bc620 SS |
417 | static inline int avc_xperms_audit(struct selinux_state *state, |
418 | u32 ssid, u32 tsid, u16 tclass, | |
419 | u32 requested, struct av_decision *avd, | |
420 | struct extended_perms_decision *xpd, | |
421 | u8 perm, int result, | |
422 | struct common_audit_data *ad) | |
fa1aa143 JVS |
423 | { |
424 | u32 audited, denied; | |
425 | ||
426 | audited = avc_xperms_audit_required( | |
427 | requested, avd, xpd, perm, result, &denied); | |
428 | if (likely(!audited)) | |
429 | return 0; | |
6b6bc620 | 430 | return slow_avc_audit(state, ssid, tsid, tclass, requested, |
0188d5c0 | 431 | audited, denied, result, ad); |
fa1aa143 JVS |
432 | } |
433 | ||
1da177e4 LT |
434 | static void avc_node_free(struct rcu_head *rhead) |
435 | { | |
436 | struct avc_node *node = container_of(rhead, struct avc_node, rhead); | |
fa1aa143 | 437 | avc_xperms_free(node->ae.xp_node); |
1da177e4 LT |
438 | kmem_cache_free(avc_node_cachep, node); |
439 | avc_cache_stats_incr(frees); | |
440 | } | |
441 | ||
6b6bc620 | 442 | static void avc_node_delete(struct selinux_avc *avc, struct avc_node *node) |
1da177e4 | 443 | { |
26036651 | 444 | hlist_del_rcu(&node->list); |
1da177e4 | 445 | call_rcu(&node->rhead, avc_node_free); |
6b6bc620 | 446 | atomic_dec(&avc->avc_cache.active_nodes); |
1da177e4 LT |
447 | } |
448 | ||
6b6bc620 | 449 | static void avc_node_kill(struct selinux_avc *avc, struct avc_node *node) |
1da177e4 | 450 | { |
fa1aa143 | 451 | avc_xperms_free(node->ae.xp_node); |
1da177e4 LT |
452 | kmem_cache_free(avc_node_cachep, node); |
453 | avc_cache_stats_incr(frees); | |
6b6bc620 | 454 | atomic_dec(&avc->avc_cache.active_nodes); |
1da177e4 LT |
455 | } |
456 | ||
6b6bc620 SS |
457 | static void avc_node_replace(struct selinux_avc *avc, |
458 | struct avc_node *new, struct avc_node *old) | |
1da177e4 | 459 | { |
26036651 | 460 | hlist_replace_rcu(&old->list, &new->list); |
1da177e4 | 461 | call_rcu(&old->rhead, avc_node_free); |
6b6bc620 | 462 | atomic_dec(&avc->avc_cache.active_nodes); |
1da177e4 LT |
463 | } |
464 | ||
6b6bc620 | 465 | static inline int avc_reclaim_node(struct selinux_avc *avc) |
1da177e4 LT |
466 | { |
467 | struct avc_node *node; | |
468 | int hvalue, try, ecx; | |
469 | unsigned long flags; | |
26036651 | 470 | struct hlist_head *head; |
edf3d1ae | 471 | spinlock_t *lock; |
1da177e4 | 472 | |
95fff33b | 473 | for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) { |
6b6bc620 SS |
474 | hvalue = atomic_inc_return(&avc->avc_cache.lru_hint) & |
475 | (AVC_CACHE_SLOTS - 1); | |
476 | head = &avc->avc_cache.slots[hvalue]; | |
477 | lock = &avc->avc_cache.slots_lock[hvalue]; | |
1da177e4 | 478 | |
edf3d1ae | 479 | if (!spin_trylock_irqsave(lock, flags)) |
1da177e4 LT |
480 | continue; |
481 | ||
61844250 | 482 | rcu_read_lock(); |
b67bfe0d | 483 | hlist_for_each_entry(node, head, list) { |
6b6bc620 | 484 | avc_node_delete(avc, node); |
906d27d9 EP |
485 | avc_cache_stats_incr(reclaims); |
486 | ecx++; | |
487 | if (ecx >= AVC_CACHE_RECLAIM) { | |
488 | rcu_read_unlock(); | |
edf3d1ae | 489 | spin_unlock_irqrestore(lock, flags); |
906d27d9 | 490 | goto out; |
1da177e4 LT |
491 | } |
492 | } | |
61844250 | 493 | rcu_read_unlock(); |
edf3d1ae | 494 | spin_unlock_irqrestore(lock, flags); |
1da177e4 LT |
495 | } |
496 | out: | |
497 | return ecx; | |
498 | } | |
499 | ||
6b6bc620 | 500 | static struct avc_node *avc_alloc_node(struct selinux_avc *avc) |
1da177e4 LT |
501 | { |
502 | struct avc_node *node; | |
503 | ||
648f2c61 | 504 | node = kmem_cache_zalloc(avc_node_cachep, GFP_NOWAIT | __GFP_NOWARN); |
1da177e4 LT |
505 | if (!node) |
506 | goto out; | |
507 | ||
26036651 | 508 | INIT_HLIST_NODE(&node->list); |
1da177e4 LT |
509 | avc_cache_stats_incr(allocations); |
510 | ||
6b6bc620 SS |
511 | if (atomic_inc_return(&avc->avc_cache.active_nodes) > |
512 | avc->avc_cache_threshold) | |
513 | avc_reclaim_node(avc); | |
1da177e4 LT |
514 | |
515 | out: | |
516 | return node; | |
517 | } | |
518 | ||
21193dcd | 519 | static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd) |
1da177e4 LT |
520 | { |
521 | node->ae.ssid = ssid; | |
522 | node->ae.tsid = tsid; | |
523 | node->ae.tclass = tclass; | |
21193dcd | 524 | memcpy(&node->ae.avd, avd, sizeof(node->ae.avd)); |
1da177e4 LT |
525 | } |
526 | ||
6b6bc620 SS |
527 | static inline struct avc_node *avc_search_node(struct selinux_avc *avc, |
528 | u32 ssid, u32 tsid, u16 tclass) | |
1da177e4 LT |
529 | { |
530 | struct avc_node *node, *ret = NULL; | |
531 | int hvalue; | |
26036651 | 532 | struct hlist_head *head; |
1da177e4 LT |
533 | |
534 | hvalue = avc_hash(ssid, tsid, tclass); | |
6b6bc620 | 535 | head = &avc->avc_cache.slots[hvalue]; |
b67bfe0d | 536 | hlist_for_each_entry_rcu(node, head, list) { |
1da177e4 LT |
537 | if (ssid == node->ae.ssid && |
538 | tclass == node->ae.tclass && | |
539 | tsid == node->ae.tsid) { | |
540 | ret = node; | |
541 | break; | |
542 | } | |
543 | } | |
544 | ||
1da177e4 LT |
545 | return ret; |
546 | } | |
547 | ||
548 | /** | |
549 | * avc_lookup - Look up an AVC entry. | |
550 | * @ssid: source security identifier | |
551 | * @tsid: target security identifier | |
552 | * @tclass: target security class | |
1da177e4 LT |
553 | * |
554 | * Look up an AVC entry that is valid for the | |
1da177e4 LT |
555 | * (@ssid, @tsid), interpreting the permissions |
556 | * based on @tclass. If a valid AVC entry exists, | |
6382dc33 | 557 | * then this function returns the avc_node. |
1da177e4 LT |
558 | * Otherwise, this function returns NULL. |
559 | */ | |
6b6bc620 SS |
560 | static struct avc_node *avc_lookup(struct selinux_avc *avc, |
561 | u32 ssid, u32 tsid, u16 tclass) | |
1da177e4 LT |
562 | { |
563 | struct avc_node *node; | |
564 | ||
565 | avc_cache_stats_incr(lookups); | |
6b6bc620 | 566 | node = avc_search_node(avc, ssid, tsid, tclass); |
1da177e4 | 567 | |
f1c6381a | 568 | if (node) |
257313b2 | 569 | return node; |
1da177e4 | 570 | |
257313b2 LT |
571 | avc_cache_stats_incr(misses); |
572 | return NULL; | |
1da177e4 LT |
573 | } |
574 | ||
6b6bc620 SS |
575 | static int avc_latest_notif_update(struct selinux_avc *avc, |
576 | int seqno, int is_insert) | |
1da177e4 LT |
577 | { |
578 | int ret = 0; | |
579 | static DEFINE_SPINLOCK(notif_lock); | |
580 | unsigned long flag; | |
581 | ||
582 | spin_lock_irqsave(¬if_lock, flag); | |
583 | if (is_insert) { | |
6b6bc620 | 584 | if (seqno < avc->avc_cache.latest_notif) { |
07c81ac2 | 585 | pr_warn("SELinux: avc: seqno %d < latest_notif %d\n", |
6b6bc620 | 586 | seqno, avc->avc_cache.latest_notif); |
1da177e4 LT |
587 | ret = -EAGAIN; |
588 | } | |
589 | } else { | |
6b6bc620 SS |
590 | if (seqno > avc->avc_cache.latest_notif) |
591 | avc->avc_cache.latest_notif = seqno; | |
1da177e4 LT |
592 | } |
593 | spin_unlock_irqrestore(¬if_lock, flag); | |
594 | ||
595 | return ret; | |
596 | } | |
597 | ||
598 | /** | |
599 | * avc_insert - Insert an AVC entry. | |
600 | * @ssid: source security identifier | |
601 | * @tsid: target security identifier | |
602 | * @tclass: target security class | |
21193dcd | 603 | * @avd: resulting av decision |
fa1aa143 | 604 | * @xp_node: resulting extended permissions |
1da177e4 LT |
605 | * |
606 | * Insert an AVC entry for the SID pair | |
607 | * (@ssid, @tsid) and class @tclass. | |
608 | * The access vectors and the sequence number are | |
609 | * normally provided by the security server in | |
610 | * response to a security_compute_av() call. If the | |
21193dcd | 611 | * sequence number @avd->seqno is not less than the latest |
1da177e4 LT |
612 | * revocation notification, then the function copies |
613 | * the access vectors into a cache entry, returns | |
614 | * avc_node inserted. Otherwise, this function returns NULL. | |
615 | */ | |
6b6bc620 SS |
616 | static struct avc_node *avc_insert(struct selinux_avc *avc, |
617 | u32 ssid, u32 tsid, u16 tclass, | |
618 | struct av_decision *avd, | |
619 | struct avc_xperms_node *xp_node) | |
1da177e4 LT |
620 | { |
621 | struct avc_node *pos, *node = NULL; | |
622 | int hvalue; | |
623 | unsigned long flag; | |
d8db60cb PM |
624 | spinlock_t *lock; |
625 | struct hlist_head *head; | |
1da177e4 | 626 | |
6b6bc620 | 627 | if (avc_latest_notif_update(avc, avd->seqno, 1)) |
d8db60cb | 628 | return NULL; |
1da177e4 | 629 | |
6b6bc620 | 630 | node = avc_alloc_node(avc); |
d8db60cb PM |
631 | if (!node) |
632 | return NULL; | |
edf3d1ae | 633 | |
d8db60cb PM |
634 | avc_node_populate(node, ssid, tsid, tclass, avd); |
635 | if (avc_xperms_populate(node, xp_node)) { | |
636 | avc_node_kill(avc, node); | |
637 | return NULL; | |
638 | } | |
639 | ||
640 | hvalue = avc_hash(ssid, tsid, tclass); | |
641 | head = &avc->avc_cache.slots[hvalue]; | |
642 | lock = &avc->avc_cache.slots_lock[hvalue]; | |
643 | spin_lock_irqsave(lock, flag); | |
644 | hlist_for_each_entry(pos, head, list) { | |
645 | if (pos->ae.ssid == ssid && | |
646 | pos->ae.tsid == tsid && | |
647 | pos->ae.tclass == tclass) { | |
648 | avc_node_replace(avc, node, pos); | |
649 | goto found; | |
1da177e4 | 650 | } |
1da177e4 | 651 | } |
d8db60cb PM |
652 | hlist_add_head_rcu(&node->list, head); |
653 | found: | |
654 | spin_unlock_irqrestore(lock, flag); | |
1da177e4 LT |
655 | return node; |
656 | } | |
657 | ||
2bf49690 TL |
658 | /** |
659 | * avc_audit_pre_callback - SELinux specific information | |
660 | * will be called by generic audit code | |
661 | * @ab: the audit buffer | |
662 | * @a: audit_data | |
663 | */ | |
664 | static void avc_audit_pre_callback(struct audit_buffer *ab, void *a) | |
1da177e4 | 665 | { |
2bf49690 | 666 | struct common_audit_data *ad = a; |
a2c51383 OM |
667 | struct selinux_audit_data *sad = ad->selinux_audit_data; |
668 | u32 av = sad->audited; | |
669 | const char **perms; | |
670 | int i, perm; | |
671 | ||
672 | audit_log_format(ab, "avc: %s ", sad->denied ? "denied" : "granted"); | |
673 | ||
674 | if (av == 0) { | |
45189a19 | 675 | audit_log_format(ab, " null"); |
a2c51383 OM |
676 | return; |
677 | } | |
678 | ||
a2c51383 OM |
679 | perms = secclass_map[sad->tclass-1].perms; |
680 | ||
45189a19 | 681 | audit_log_format(ab, " {"); |
a2c51383 OM |
682 | i = 0; |
683 | perm = 1; | |
684 | while (i < (sizeof(av) * 8)) { | |
685 | if ((perm & av) && perms[i]) { | |
686 | audit_log_format(ab, " %s", perms[i]); | |
687 | av &= ~perm; | |
688 | } | |
689 | i++; | |
690 | perm <<= 1; | |
691 | } | |
692 | ||
693 | if (av) | |
694 | audit_log_format(ab, " 0x%x", av); | |
695 | ||
45189a19 | 696 | audit_log_format(ab, " } for "); |
1da177e4 LT |
697 | } |
698 | ||
2bf49690 TL |
699 | /** |
700 | * avc_audit_post_callback - SELinux specific information | |
701 | * will be called by generic audit code | |
702 | * @ab: the audit buffer | |
703 | * @a: audit_data | |
704 | */ | |
705 | static void avc_audit_post_callback(struct audit_buffer *ab, void *a) | |
1da177e4 | 706 | { |
2bf49690 | 707 | struct common_audit_data *ad = a; |
a2c51383 | 708 | struct selinux_audit_data *sad = ad->selinux_audit_data; |
30969bc8 PE |
709 | char *scontext = NULL; |
710 | char *tcontext = NULL; | |
711 | const char *tclass = NULL; | |
a2c51383 | 712 | u32 scontext_len; |
30969bc8 | 713 | u32 tcontext_len; |
a2c51383 OM |
714 | int rc; |
715 | ||
716 | rc = security_sid_to_context(sad->state, sad->ssid, &scontext, | |
717 | &scontext_len); | |
718 | if (rc) | |
719 | audit_log_format(ab, " ssid=%d", sad->ssid); | |
30969bc8 | 720 | else |
a2c51383 | 721 | audit_log_format(ab, " scontext=%s", scontext); |
a2c51383 | 722 | |
30969bc8 PE |
723 | rc = security_sid_to_context(sad->state, sad->tsid, &tcontext, |
724 | &tcontext_len); | |
a2c51383 OM |
725 | if (rc) |
726 | audit_log_format(ab, " tsid=%d", sad->tsid); | |
30969bc8 PE |
727 | else |
728 | audit_log_format(ab, " tcontext=%s", tcontext); | |
a2c51383 | 729 | |
30969bc8 PE |
730 | tclass = secclass_map[sad->tclass-1].name; |
731 | audit_log_format(ab, " tclass=%s", tclass); | |
a2c51383 OM |
732 | |
733 | if (sad->denied) | |
734 | audit_log_format(ab, " permissive=%u", sad->result ? 0 : 1); | |
fede1483 | 735 | |
30969bc8 PE |
736 | trace_selinux_audited(sad, scontext, tcontext, tclass); |
737 | kfree(tcontext); | |
738 | kfree(scontext); | |
739 | ||
fede1483 OM |
740 | /* in case of invalid context report also the actual context string */ |
741 | rc = security_sid_to_context_inval(sad->state, sad->ssid, &scontext, | |
742 | &scontext_len); | |
743 | if (!rc && scontext) { | |
aff7ed48 OM |
744 | if (scontext_len && scontext[scontext_len - 1] == '\0') |
745 | scontext_len--; | |
746 | audit_log_format(ab, " srawcon="); | |
747 | audit_log_n_untrustedstring(ab, scontext, scontext_len); | |
fede1483 OM |
748 | kfree(scontext); |
749 | } | |
750 | ||
751 | rc = security_sid_to_context_inval(sad->state, sad->tsid, &scontext, | |
752 | &scontext_len); | |
753 | if (!rc && scontext) { | |
aff7ed48 OM |
754 | if (scontext_len && scontext[scontext_len - 1] == '\0') |
755 | scontext_len--; | |
756 | audit_log_format(ab, " trawcon="); | |
757 | audit_log_n_untrustedstring(ab, scontext, scontext_len); | |
fede1483 OM |
758 | kfree(scontext); |
759 | } | |
1da177e4 LT |
760 | } |
761 | ||
b17ec22f AV |
762 | /* |
763 | * This is the slow part of avc audit with big stack footprint. | |
764 | * Note that it is non-blocking and can be called from under | |
765 | * rcu_read_lock(). | |
766 | */ | |
6b6bc620 SS |
767 | noinline int slow_avc_audit(struct selinux_state *state, |
768 | u32 ssid, u32 tsid, u16 tclass, | |
769 | u32 requested, u32 audited, u32 denied, int result, | |
0188d5c0 | 770 | struct common_audit_data *a) |
48aab2f7 LT |
771 | { |
772 | struct common_audit_data stack_data; | |
899838b2 | 773 | struct selinux_audit_data sad; |
48aab2f7 | 774 | |
994fb065 OM |
775 | if (WARN_ON(!tclass || tclass >= ARRAY_SIZE(secclass_map))) |
776 | return -EINVAL; | |
777 | ||
48aab2f7 LT |
778 | if (!a) { |
779 | a = &stack_data; | |
50c205f5 | 780 | a->type = LSM_AUDIT_DATA_NONE; |
48aab2f7 LT |
781 | } |
782 | ||
899838b2 EP |
783 | sad.tclass = tclass; |
784 | sad.requested = requested; | |
785 | sad.ssid = ssid; | |
786 | sad.tsid = tsid; | |
787 | sad.audited = audited; | |
788 | sad.denied = denied; | |
ca7786a2 | 789 | sad.result = result; |
6b6bc620 | 790 | sad.state = state; |
899838b2 EP |
791 | |
792 | a->selinux_audit_data = &sad; | |
3f0882c4 | 793 | |
b61c37f5 | 794 | common_lsm_audit(a, avc_audit_pre_callback, avc_audit_post_callback); |
48aab2f7 LT |
795 | return 0; |
796 | } | |
797 | ||
1da177e4 LT |
798 | /** |
799 | * avc_add_callback - Register a callback for security events. | |
800 | * @callback: callback function | |
801 | * @events: security events | |
1da177e4 | 802 | * |
562c99f2 WG |
803 | * Register a callback function for events in the set @events. |
804 | * Returns %0 on success or -%ENOMEM if insufficient memory | |
805 | * exists to add the callback. | |
1da177e4 | 806 | */ |
562c99f2 | 807 | int __init avc_add_callback(int (*callback)(u32 event), u32 events) |
1da177e4 LT |
808 | { |
809 | struct avc_callback_node *c; | |
810 | int rc = 0; | |
811 | ||
0b36e44c | 812 | c = kmalloc(sizeof(*c), GFP_KERNEL); |
1da177e4 LT |
813 | if (!c) { |
814 | rc = -ENOMEM; | |
815 | goto out; | |
816 | } | |
817 | ||
818 | c->callback = callback; | |
819 | c->events = events; | |
1da177e4 LT |
820 | c->next = avc_callbacks; |
821 | avc_callbacks = c; | |
822 | out: | |
823 | return rc; | |
824 | } | |
825 | ||
1da177e4 | 826 | /** |
7cffc377 | 827 | * avc_update_node - Update an AVC entry |
1da177e4 LT |
828 | * @event : Updating event |
829 | * @perms : Permission mask bits | |
830 | * @ssid,@tsid,@tclass : identifier of an AVC entry | |
a5dda683 | 831 | * @seqno : sequence number when decision was made |
fa1aa143 | 832 | * @xpd: extended_perms_decision to be added to the node |
b17ec22f | 833 | * @flags: the AVC_* flags, e.g. AVC_EXTENDED_PERMS, or 0. |
1da177e4 LT |
834 | * |
835 | * if a valid AVC entry doesn't exist,this function returns -ENOENT. | |
836 | * if kmalloc() called internal returns NULL, this function returns -ENOMEM. | |
6382dc33 | 837 | * otherwise, this function updates the AVC entry. The original AVC-entry object |
1da177e4 LT |
838 | * will release later by RCU. |
839 | */ | |
6b6bc620 SS |
840 | static int avc_update_node(struct selinux_avc *avc, |
841 | u32 event, u32 perms, u8 driver, u8 xperm, u32 ssid, | |
842 | u32 tsid, u16 tclass, u32 seqno, | |
843 | struct extended_perms_decision *xpd, | |
844 | u32 flags) | |
1da177e4 LT |
845 | { |
846 | int hvalue, rc = 0; | |
847 | unsigned long flag; | |
848 | struct avc_node *pos, *node, *orig = NULL; | |
26036651 | 849 | struct hlist_head *head; |
edf3d1ae | 850 | spinlock_t *lock; |
1da177e4 | 851 | |
6b6bc620 | 852 | node = avc_alloc_node(avc); |
1da177e4 LT |
853 | if (!node) { |
854 | rc = -ENOMEM; | |
855 | goto out; | |
856 | } | |
857 | ||
858 | /* Lock the target slot */ | |
859 | hvalue = avc_hash(ssid, tsid, tclass); | |
1da177e4 | 860 | |
6b6bc620 SS |
861 | head = &avc->avc_cache.slots[hvalue]; |
862 | lock = &avc->avc_cache.slots_lock[hvalue]; | |
edf3d1ae EP |
863 | |
864 | spin_lock_irqsave(lock, flag); | |
865 | ||
b67bfe0d | 866 | hlist_for_each_entry(pos, head, list) { |
95fff33b EP |
867 | if (ssid == pos->ae.ssid && |
868 | tsid == pos->ae.tsid && | |
a5dda683 EP |
869 | tclass == pos->ae.tclass && |
870 | seqno == pos->ae.avd.seqno){ | |
1da177e4 LT |
871 | orig = pos; |
872 | break; | |
873 | } | |
874 | } | |
875 | ||
876 | if (!orig) { | |
877 | rc = -ENOENT; | |
6b6bc620 | 878 | avc_node_kill(avc, node); |
1da177e4 LT |
879 | goto out_unlock; |
880 | } | |
881 | ||
882 | /* | |
883 | * Copy and replace original node. | |
884 | */ | |
885 | ||
21193dcd | 886 | avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd); |
1da177e4 | 887 | |
fa1aa143 JVS |
888 | if (orig->ae.xp_node) { |
889 | rc = avc_xperms_populate(node, orig->ae.xp_node); | |
890 | if (rc) { | |
030b995a | 891 | avc_node_kill(avc, node); |
fa1aa143 JVS |
892 | goto out_unlock; |
893 | } | |
894 | } | |
895 | ||
1da177e4 LT |
896 | switch (event) { |
897 | case AVC_CALLBACK_GRANT: | |
898 | node->ae.avd.allowed |= perms; | |
fa1aa143 JVS |
899 | if (node->ae.xp_node && (flags & AVC_EXTENDED_PERMS)) |
900 | avc_xperms_allow_perm(node->ae.xp_node, driver, xperm); | |
1da177e4 LT |
901 | break; |
902 | case AVC_CALLBACK_TRY_REVOKE: | |
903 | case AVC_CALLBACK_REVOKE: | |
904 | node->ae.avd.allowed &= ~perms; | |
905 | break; | |
906 | case AVC_CALLBACK_AUDITALLOW_ENABLE: | |
907 | node->ae.avd.auditallow |= perms; | |
908 | break; | |
909 | case AVC_CALLBACK_AUDITALLOW_DISABLE: | |
910 | node->ae.avd.auditallow &= ~perms; | |
911 | break; | |
912 | case AVC_CALLBACK_AUDITDENY_ENABLE: | |
913 | node->ae.avd.auditdeny |= perms; | |
914 | break; | |
915 | case AVC_CALLBACK_AUDITDENY_DISABLE: | |
916 | node->ae.avd.auditdeny &= ~perms; | |
917 | break; | |
fa1aa143 JVS |
918 | case AVC_CALLBACK_ADD_XPERMS: |
919 | avc_add_xperms_decision(node, xpd); | |
920 | break; | |
1da177e4 | 921 | } |
6b6bc620 | 922 | avc_node_replace(avc, node, orig); |
1da177e4 | 923 | out_unlock: |
edf3d1ae | 924 | spin_unlock_irqrestore(lock, flag); |
1da177e4 LT |
925 | out: |
926 | return rc; | |
927 | } | |
928 | ||
929 | /** | |
008574b1 | 930 | * avc_flush - Flush the cache |
1da177e4 | 931 | */ |
6b6bc620 | 932 | static void avc_flush(struct selinux_avc *avc) |
1da177e4 | 933 | { |
26036651 | 934 | struct hlist_head *head; |
008574b1 | 935 | struct avc_node *node; |
edf3d1ae | 936 | spinlock_t *lock; |
008574b1 EP |
937 | unsigned long flag; |
938 | int i; | |
1da177e4 LT |
939 | |
940 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { | |
6b6bc620 SS |
941 | head = &avc->avc_cache.slots[i]; |
942 | lock = &avc->avc_cache.slots_lock[i]; | |
edf3d1ae EP |
943 | |
944 | spin_lock_irqsave(lock, flag); | |
61844250 PM |
945 | /* |
946 | * With preemptable RCU, the outer spinlock does not | |
947 | * prevent RCU grace periods from ending. | |
948 | */ | |
949 | rcu_read_lock(); | |
b67bfe0d | 950 | hlist_for_each_entry(node, head, list) |
6b6bc620 | 951 | avc_node_delete(avc, node); |
61844250 | 952 | rcu_read_unlock(); |
edf3d1ae | 953 | spin_unlock_irqrestore(lock, flag); |
1da177e4 | 954 | } |
008574b1 EP |
955 | } |
956 | ||
957 | /** | |
958 | * avc_ss_reset - Flush the cache and revalidate migrated permissions. | |
959 | * @seqno: policy sequence number | |
960 | */ | |
6b6bc620 | 961 | int avc_ss_reset(struct selinux_avc *avc, u32 seqno) |
008574b1 EP |
962 | { |
963 | struct avc_callback_node *c; | |
964 | int rc = 0, tmprc; | |
965 | ||
6b6bc620 | 966 | avc_flush(avc); |
1da177e4 LT |
967 | |
968 | for (c = avc_callbacks; c; c = c->next) { | |
969 | if (c->events & AVC_CALLBACK_RESET) { | |
562c99f2 | 970 | tmprc = c->callback(AVC_CALLBACK_RESET); |
376bd9cb DG |
971 | /* save the first error encountered for the return |
972 | value and continue processing the callbacks */ | |
973 | if (!rc) | |
974 | rc = tmprc; | |
1da177e4 LT |
975 | } |
976 | } | |
977 | ||
6b6bc620 | 978 | avc_latest_notif_update(avc, seqno, 0); |
1da177e4 LT |
979 | return rc; |
980 | } | |
981 | ||
a554bea8 LT |
982 | /* |
983 | * Slow-path helper function for avc_has_perm_noaudit, | |
984 | * when the avc_node lookup fails. We get called with | |
985 | * the RCU read lock held, and need to return with it | |
986 | * still held, but drop if for the security compute. | |
987 | * | |
988 | * Don't inline this, since it's the slow-path and just | |
989 | * results in a bigger stack frame. | |
990 | */ | |
6b6bc620 SS |
991 | static noinline |
992 | struct avc_node *avc_compute_av(struct selinux_state *state, | |
993 | u32 ssid, u32 tsid, | |
994 | u16 tclass, struct av_decision *avd, | |
995 | struct avc_xperms_node *xp_node) | |
a554bea8 LT |
996 | { |
997 | rcu_read_unlock(); | |
fa1aa143 | 998 | INIT_LIST_HEAD(&xp_node->xpd_head); |
6b6bc620 | 999 | security_compute_av(state, ssid, tsid, tclass, avd, &xp_node->xp); |
a554bea8 | 1000 | rcu_read_lock(); |
6b6bc620 | 1001 | return avc_insert(state->avc, ssid, tsid, tclass, avd, xp_node); |
a554bea8 LT |
1002 | } |
1003 | ||
6b6bc620 SS |
1004 | static noinline int avc_denied(struct selinux_state *state, |
1005 | u32 ssid, u32 tsid, | |
1006 | u16 tclass, u32 requested, | |
1007 | u8 driver, u8 xperm, unsigned int flags, | |
1008 | struct av_decision *avd) | |
a554bea8 LT |
1009 | { |
1010 | if (flags & AVC_STRICT) | |
1011 | return -EACCES; | |
1012 | ||
6b6bc620 | 1013 | if (enforcing_enabled(state) && |
aa8e712c | 1014 | !(avd->flags & AVD_FLAGS_PERMISSIVE)) |
a554bea8 LT |
1015 | return -EACCES; |
1016 | ||
6b6bc620 SS |
1017 | avc_update_node(state->avc, AVC_CALLBACK_GRANT, requested, driver, |
1018 | xperm, ssid, tsid, tclass, avd->seqno, NULL, flags); | |
a554bea8 LT |
1019 | return 0; |
1020 | } | |
1021 | ||
fa1aa143 JVS |
1022 | /* |
1023 | * The avc extended permissions logic adds an additional 256 bits of | |
1024 | * permissions to an avc node when extended permissions for that node are | |
1025 | * specified in the avtab. If the additional 256 permissions is not adequate, | |
1026 | * as-is the case with ioctls, then multiple may be chained together and the | |
1027 | * driver field is used to specify which set contains the permission. | |
1028 | */ | |
6b6bc620 SS |
1029 | int avc_has_extended_perms(struct selinux_state *state, |
1030 | u32 ssid, u32 tsid, u16 tclass, u32 requested, | |
1031 | u8 driver, u8 xperm, struct common_audit_data *ad) | |
fa1aa143 JVS |
1032 | { |
1033 | struct avc_node *node; | |
1034 | struct av_decision avd; | |
1035 | u32 denied; | |
1036 | struct extended_perms_decision local_xpd; | |
1037 | struct extended_perms_decision *xpd = NULL; | |
1038 | struct extended_perms_data allowed; | |
1039 | struct extended_perms_data auditallow; | |
1040 | struct extended_perms_data dontaudit; | |
1041 | struct avc_xperms_node local_xp_node; | |
1042 | struct avc_xperms_node *xp_node; | |
1043 | int rc = 0, rc2; | |
1044 | ||
1045 | xp_node = &local_xp_node; | |
e6f2f381 OM |
1046 | if (WARN_ON(!requested)) |
1047 | return -EACCES; | |
fa1aa143 JVS |
1048 | |
1049 | rcu_read_lock(); | |
1050 | ||
6b6bc620 | 1051 | node = avc_lookup(state->avc, ssid, tsid, tclass); |
fa1aa143 | 1052 | if (unlikely(!node)) { |
6b6bc620 | 1053 | node = avc_compute_av(state, ssid, tsid, tclass, &avd, xp_node); |
fa1aa143 JVS |
1054 | } else { |
1055 | memcpy(&avd, &node->ae.avd, sizeof(avd)); | |
1056 | xp_node = node->ae.xp_node; | |
1057 | } | |
1058 | /* if extended permissions are not defined, only consider av_decision */ | |
1059 | if (!xp_node || !xp_node->xp.len) | |
1060 | goto decision; | |
1061 | ||
1062 | local_xpd.allowed = &allowed; | |
1063 | local_xpd.auditallow = &auditallow; | |
1064 | local_xpd.dontaudit = &dontaudit; | |
1065 | ||
1066 | xpd = avc_xperms_decision_lookup(driver, xp_node); | |
1067 | if (unlikely(!xpd)) { | |
1068 | /* | |
1069 | * Compute the extended_perms_decision only if the driver | |
1070 | * is flagged | |
1071 | */ | |
1072 | if (!security_xperm_test(xp_node->xp.drivers.p, driver)) { | |
1073 | avd.allowed &= ~requested; | |
1074 | goto decision; | |
1075 | } | |
1076 | rcu_read_unlock(); | |
6b6bc620 SS |
1077 | security_compute_xperms_decision(state, ssid, tsid, tclass, |
1078 | driver, &local_xpd); | |
fa1aa143 | 1079 | rcu_read_lock(); |
6b6bc620 SS |
1080 | avc_update_node(state->avc, AVC_CALLBACK_ADD_XPERMS, requested, |
1081 | driver, xperm, ssid, tsid, tclass, avd.seqno, | |
1082 | &local_xpd, 0); | |
fa1aa143 JVS |
1083 | } else { |
1084 | avc_quick_copy_xperms_decision(xperm, &local_xpd, xpd); | |
1085 | } | |
1086 | xpd = &local_xpd; | |
1087 | ||
1088 | if (!avc_xperms_has_perm(xpd, xperm, XPERMS_ALLOWED)) | |
1089 | avd.allowed &= ~requested; | |
1090 | ||
1091 | decision: | |
1092 | denied = requested & ~(avd.allowed); | |
1093 | if (unlikely(denied)) | |
6b6bc620 SS |
1094 | rc = avc_denied(state, ssid, tsid, tclass, requested, |
1095 | driver, xperm, AVC_EXTENDED_PERMS, &avd); | |
fa1aa143 JVS |
1096 | |
1097 | rcu_read_unlock(); | |
1098 | ||
6b6bc620 | 1099 | rc2 = avc_xperms_audit(state, ssid, tsid, tclass, requested, |
fa1aa143 JVS |
1100 | &avd, xpd, xperm, rc, ad); |
1101 | if (rc2) | |
1102 | return rc2; | |
1103 | return rc; | |
1104 | } | |
a554bea8 | 1105 | |
1da177e4 LT |
1106 | /** |
1107 | * avc_has_perm_noaudit - Check permissions but perform no auditing. | |
1108 | * @ssid: source security identifier | |
1109 | * @tsid: target security identifier | |
1110 | * @tclass: target security class | |
1111 | * @requested: requested permissions, interpreted based on @tclass | |
b17ec22f | 1112 | * @flags: AVC_STRICT or 0 |
1da177e4 LT |
1113 | * @avd: access vector decisions |
1114 | * | |
1115 | * Check the AVC to determine whether the @requested permissions are granted | |
1116 | * for the SID pair (@ssid, @tsid), interpreting the permissions | |
1117 | * based on @tclass, and call the security server on a cache miss to obtain | |
1118 | * a new decision and add it to the cache. Return a copy of the decisions | |
1119 | * in @avd. Return %0 if all @requested permissions are granted, | |
1120 | * -%EACCES if any permissions are denied, or another -errno upon | |
1121 | * other errors. This function is typically called by avc_has_perm(), | |
1122 | * but may also be called directly to separate permission checking from | |
1123 | * auditing, e.g. in cases where a lock must be held for the check but | |
1124 | * should be released for the auditing. | |
1125 | */ | |
6b6bc620 SS |
1126 | inline int avc_has_perm_noaudit(struct selinux_state *state, |
1127 | u32 ssid, u32 tsid, | |
1128 | u16 tclass, u32 requested, | |
1129 | unsigned int flags, | |
1130 | struct av_decision *avd) | |
1da177e4 LT |
1131 | { |
1132 | struct avc_node *node; | |
fa1aa143 | 1133 | struct avc_xperms_node xp_node; |
1da177e4 LT |
1134 | int rc = 0; |
1135 | u32 denied; | |
1136 | ||
e6f2f381 OM |
1137 | if (WARN_ON(!requested)) |
1138 | return -EACCES; | |
eda4f69c | 1139 | |
1da177e4 LT |
1140 | rcu_read_lock(); |
1141 | ||
6b6bc620 | 1142 | node = avc_lookup(state->avc, ssid, tsid, tclass); |
83d4a806 | 1143 | if (unlikely(!node)) |
6b6bc620 | 1144 | node = avc_compute_av(state, ssid, tsid, tclass, avd, &xp_node); |
83d4a806 | 1145 | else |
f01e1af4 | 1146 | memcpy(avd, &node->ae.avd, sizeof(*avd)); |
1da177e4 | 1147 | |
21193dcd | 1148 | denied = requested & ~(avd->allowed); |
a554bea8 | 1149 | if (unlikely(denied)) |
6b6bc620 SS |
1150 | rc = avc_denied(state, ssid, tsid, tclass, requested, 0, 0, |
1151 | flags, avd); | |
1da177e4 LT |
1152 | |
1153 | rcu_read_unlock(); | |
1da177e4 LT |
1154 | return rc; |
1155 | } | |
1156 | ||
1157 | /** | |
1158 | * avc_has_perm - Check permissions and perform any appropriate auditing. | |
1159 | * @ssid: source security identifier | |
1160 | * @tsid: target security identifier | |
1161 | * @tclass: target security class | |
1162 | * @requested: requested permissions, interpreted based on @tclass | |
1163 | * @auditdata: auxiliary audit data | |
1164 | * | |
1165 | * Check the AVC to determine whether the @requested permissions are granted | |
1166 | * for the SID pair (@ssid, @tsid), interpreting the permissions | |
1167 | * based on @tclass, and call the security server on a cache miss to obtain | |
1168 | * a new decision and add it to the cache. Audit the granting or denial of | |
1169 | * permissions in accordance with the policy. Return %0 if all @requested | |
1170 | * permissions are granted, -%EACCES if any permissions are denied, or | |
1171 | * another -errno upon other errors. | |
1172 | */ | |
6b6bc620 | 1173 | int avc_has_perm(struct selinux_state *state, u32 ssid, u32 tsid, u16 tclass, |
cb4fbe57 | 1174 | u32 requested, struct common_audit_data *auditdata) |
1da177e4 LT |
1175 | { |
1176 | struct av_decision avd; | |
9ade0cf4 | 1177 | int rc, rc2; |
1da177e4 | 1178 | |
6b6bc620 SS |
1179 | rc = avc_has_perm_noaudit(state, ssid, tsid, tclass, requested, 0, |
1180 | &avd); | |
9ade0cf4 | 1181 | |
6b6bc620 | 1182 | rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc, |
d99cf13f | 1183 | auditdata); |
1a37079c SS |
1184 | if (rc2) |
1185 | return rc2; | |
1186 | return rc; | |
1187 | } | |
1188 | ||
6b6bc620 | 1189 | u32 avc_policy_seqno(struct selinux_state *state) |
788e7dd4 | 1190 | { |
6b6bc620 | 1191 | return state->avc->avc_cache.latest_notif; |
788e7dd4 | 1192 | } |
89c86576 TL |
1193 | |
1194 | void avc_disable(void) | |
1195 | { | |
5224ee08 EP |
1196 | /* |
1197 | * If you are looking at this because you have realized that we are | |
1198 | * not destroying the avc_node_cachep it might be easy to fix, but | |
1199 | * I don't know the memory barrier semantics well enough to know. It's | |
1200 | * possible that some other task dereferenced security_ops when | |
1201 | * it still pointed to selinux operations. If that is the case it's | |
1202 | * possible that it is about to use the avc and is about to need the | |
1203 | * avc_node_cachep. I know I could wrap the security.c security_ops call | |
1204 | * in an rcu_lock, but seriously, it's not worth it. Instead I just flush | |
1205 | * the cache and get that memory back. | |
1206 | */ | |
1207 | if (avc_node_cachep) { | |
6b6bc620 | 1208 | avc_flush(selinux_state.avc); |
5224ee08 EP |
1209 | /* kmem_cache_destroy(avc_node_cachep); */ |
1210 | } | |
89c86576 | 1211 | } |