Commit | Line | Data |
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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. | |
e9fd7292 | 550 | * @avc: the access vector cache |
1da177e4 LT |
551 | * @ssid: source security identifier |
552 | * @tsid: target security identifier | |
553 | * @tclass: target security class | |
1da177e4 LT |
554 | * |
555 | * Look up an AVC entry that is valid for the | |
1da177e4 LT |
556 | * (@ssid, @tsid), interpreting the permissions |
557 | * based on @tclass. If a valid AVC entry exists, | |
6382dc33 | 558 | * then this function returns the avc_node. |
1da177e4 LT |
559 | * Otherwise, this function returns NULL. |
560 | */ | |
6b6bc620 SS |
561 | static struct avc_node *avc_lookup(struct selinux_avc *avc, |
562 | u32 ssid, u32 tsid, u16 tclass) | |
1da177e4 LT |
563 | { |
564 | struct avc_node *node; | |
565 | ||
566 | avc_cache_stats_incr(lookups); | |
6b6bc620 | 567 | node = avc_search_node(avc, ssid, tsid, tclass); |
1da177e4 | 568 | |
f1c6381a | 569 | if (node) |
257313b2 | 570 | return node; |
1da177e4 | 571 | |
257313b2 LT |
572 | avc_cache_stats_incr(misses); |
573 | return NULL; | |
1da177e4 LT |
574 | } |
575 | ||
6b6bc620 SS |
576 | static int avc_latest_notif_update(struct selinux_avc *avc, |
577 | int seqno, int is_insert) | |
1da177e4 LT |
578 | { |
579 | int ret = 0; | |
580 | static DEFINE_SPINLOCK(notif_lock); | |
581 | unsigned long flag; | |
582 | ||
583 | spin_lock_irqsave(¬if_lock, flag); | |
584 | if (is_insert) { | |
6b6bc620 | 585 | if (seqno < avc->avc_cache.latest_notif) { |
07c81ac2 | 586 | pr_warn("SELinux: avc: seqno %d < latest_notif %d\n", |
6b6bc620 | 587 | seqno, avc->avc_cache.latest_notif); |
1da177e4 LT |
588 | ret = -EAGAIN; |
589 | } | |
590 | } else { | |
6b6bc620 SS |
591 | if (seqno > avc->avc_cache.latest_notif) |
592 | avc->avc_cache.latest_notif = seqno; | |
1da177e4 LT |
593 | } |
594 | spin_unlock_irqrestore(¬if_lock, flag); | |
595 | ||
596 | return ret; | |
597 | } | |
598 | ||
599 | /** | |
600 | * avc_insert - Insert an AVC entry. | |
e9fd7292 | 601 | * @avc: the access vector cache |
1da177e4 LT |
602 | * @ssid: source security identifier |
603 | * @tsid: target security identifier | |
604 | * @tclass: target security class | |
21193dcd | 605 | * @avd: resulting av decision |
fa1aa143 | 606 | * @xp_node: resulting extended permissions |
1da177e4 LT |
607 | * |
608 | * Insert an AVC entry for the SID pair | |
609 | * (@ssid, @tsid) and class @tclass. | |
610 | * The access vectors and the sequence number are | |
611 | * normally provided by the security server in | |
612 | * response to a security_compute_av() call. If the | |
21193dcd | 613 | * sequence number @avd->seqno is not less than the latest |
1da177e4 LT |
614 | * revocation notification, then the function copies |
615 | * the access vectors into a cache entry, returns | |
616 | * avc_node inserted. Otherwise, this function returns NULL. | |
617 | */ | |
6b6bc620 SS |
618 | static struct avc_node *avc_insert(struct selinux_avc *avc, |
619 | u32 ssid, u32 tsid, u16 tclass, | |
620 | struct av_decision *avd, | |
621 | struct avc_xperms_node *xp_node) | |
1da177e4 LT |
622 | { |
623 | struct avc_node *pos, *node = NULL; | |
624 | int hvalue; | |
625 | unsigned long flag; | |
d8db60cb PM |
626 | spinlock_t *lock; |
627 | struct hlist_head *head; | |
1da177e4 | 628 | |
6b6bc620 | 629 | if (avc_latest_notif_update(avc, avd->seqno, 1)) |
d8db60cb | 630 | return NULL; |
1da177e4 | 631 | |
6b6bc620 | 632 | node = avc_alloc_node(avc); |
d8db60cb PM |
633 | if (!node) |
634 | return NULL; | |
edf3d1ae | 635 | |
d8db60cb PM |
636 | avc_node_populate(node, ssid, tsid, tclass, avd); |
637 | if (avc_xperms_populate(node, xp_node)) { | |
638 | avc_node_kill(avc, node); | |
639 | return NULL; | |
640 | } | |
641 | ||
642 | hvalue = avc_hash(ssid, tsid, tclass); | |
643 | head = &avc->avc_cache.slots[hvalue]; | |
644 | lock = &avc->avc_cache.slots_lock[hvalue]; | |
645 | spin_lock_irqsave(lock, flag); | |
646 | hlist_for_each_entry(pos, head, list) { | |
647 | if (pos->ae.ssid == ssid && | |
648 | pos->ae.tsid == tsid && | |
649 | pos->ae.tclass == tclass) { | |
650 | avc_node_replace(avc, node, pos); | |
651 | goto found; | |
1da177e4 | 652 | } |
1da177e4 | 653 | } |
d8db60cb PM |
654 | hlist_add_head_rcu(&node->list, head); |
655 | found: | |
656 | spin_unlock_irqrestore(lock, flag); | |
1da177e4 LT |
657 | return node; |
658 | } | |
659 | ||
2bf49690 TL |
660 | /** |
661 | * avc_audit_pre_callback - SELinux specific information | |
662 | * will be called by generic audit code | |
663 | * @ab: the audit buffer | |
664 | * @a: audit_data | |
665 | */ | |
666 | static void avc_audit_pre_callback(struct audit_buffer *ab, void *a) | |
1da177e4 | 667 | { |
2bf49690 | 668 | struct common_audit_data *ad = a; |
a2c51383 OM |
669 | struct selinux_audit_data *sad = ad->selinux_audit_data; |
670 | u32 av = sad->audited; | |
671 | const char **perms; | |
672 | int i, perm; | |
673 | ||
674 | audit_log_format(ab, "avc: %s ", sad->denied ? "denied" : "granted"); | |
675 | ||
676 | if (av == 0) { | |
45189a19 | 677 | audit_log_format(ab, " null"); |
a2c51383 OM |
678 | return; |
679 | } | |
680 | ||
a2c51383 OM |
681 | perms = secclass_map[sad->tclass-1].perms; |
682 | ||
45189a19 | 683 | audit_log_format(ab, " {"); |
a2c51383 OM |
684 | i = 0; |
685 | perm = 1; | |
686 | while (i < (sizeof(av) * 8)) { | |
687 | if ((perm & av) && perms[i]) { | |
688 | audit_log_format(ab, " %s", perms[i]); | |
689 | av &= ~perm; | |
690 | } | |
691 | i++; | |
692 | perm <<= 1; | |
693 | } | |
694 | ||
695 | if (av) | |
696 | audit_log_format(ab, " 0x%x", av); | |
697 | ||
45189a19 | 698 | audit_log_format(ab, " } for "); |
1da177e4 LT |
699 | } |
700 | ||
2bf49690 TL |
701 | /** |
702 | * avc_audit_post_callback - SELinux specific information | |
703 | * will be called by generic audit code | |
704 | * @ab: the audit buffer | |
705 | * @a: audit_data | |
706 | */ | |
707 | static void avc_audit_post_callback(struct audit_buffer *ab, void *a) | |
1da177e4 | 708 | { |
2bf49690 | 709 | struct common_audit_data *ad = a; |
a2c51383 | 710 | struct selinux_audit_data *sad = ad->selinux_audit_data; |
30969bc8 PE |
711 | char *scontext = NULL; |
712 | char *tcontext = NULL; | |
713 | const char *tclass = NULL; | |
a2c51383 | 714 | u32 scontext_len; |
30969bc8 | 715 | u32 tcontext_len; |
a2c51383 OM |
716 | int rc; |
717 | ||
718 | rc = security_sid_to_context(sad->state, sad->ssid, &scontext, | |
719 | &scontext_len); | |
720 | if (rc) | |
721 | audit_log_format(ab, " ssid=%d", sad->ssid); | |
30969bc8 | 722 | else |
a2c51383 | 723 | audit_log_format(ab, " scontext=%s", scontext); |
a2c51383 | 724 | |
30969bc8 PE |
725 | rc = security_sid_to_context(sad->state, sad->tsid, &tcontext, |
726 | &tcontext_len); | |
a2c51383 OM |
727 | if (rc) |
728 | audit_log_format(ab, " tsid=%d", sad->tsid); | |
30969bc8 PE |
729 | else |
730 | audit_log_format(ab, " tcontext=%s", tcontext); | |
a2c51383 | 731 | |
30969bc8 PE |
732 | tclass = secclass_map[sad->tclass-1].name; |
733 | audit_log_format(ab, " tclass=%s", tclass); | |
a2c51383 OM |
734 | |
735 | if (sad->denied) | |
736 | audit_log_format(ab, " permissive=%u", sad->result ? 0 : 1); | |
fede1483 | 737 | |
30969bc8 PE |
738 | trace_selinux_audited(sad, scontext, tcontext, tclass); |
739 | kfree(tcontext); | |
740 | kfree(scontext); | |
741 | ||
fede1483 OM |
742 | /* in case of invalid context report also the actual context string */ |
743 | rc = security_sid_to_context_inval(sad->state, sad->ssid, &scontext, | |
744 | &scontext_len); | |
745 | if (!rc && scontext) { | |
aff7ed48 OM |
746 | if (scontext_len && scontext[scontext_len - 1] == '\0') |
747 | scontext_len--; | |
748 | audit_log_format(ab, " srawcon="); | |
749 | audit_log_n_untrustedstring(ab, scontext, scontext_len); | |
fede1483 OM |
750 | kfree(scontext); |
751 | } | |
752 | ||
753 | rc = security_sid_to_context_inval(sad->state, sad->tsid, &scontext, | |
754 | &scontext_len); | |
755 | if (!rc && scontext) { | |
aff7ed48 OM |
756 | if (scontext_len && scontext[scontext_len - 1] == '\0') |
757 | scontext_len--; | |
758 | audit_log_format(ab, " trawcon="); | |
759 | audit_log_n_untrustedstring(ab, scontext, scontext_len); | |
fede1483 OM |
760 | kfree(scontext); |
761 | } | |
1da177e4 LT |
762 | } |
763 | ||
b17ec22f AV |
764 | /* |
765 | * This is the slow part of avc audit with big stack footprint. | |
766 | * Note that it is non-blocking and can be called from under | |
767 | * rcu_read_lock(). | |
768 | */ | |
6b6bc620 SS |
769 | noinline int slow_avc_audit(struct selinux_state *state, |
770 | u32 ssid, u32 tsid, u16 tclass, | |
771 | u32 requested, u32 audited, u32 denied, int result, | |
0188d5c0 | 772 | struct common_audit_data *a) |
48aab2f7 LT |
773 | { |
774 | struct common_audit_data stack_data; | |
899838b2 | 775 | struct selinux_audit_data sad; |
48aab2f7 | 776 | |
994fb065 OM |
777 | if (WARN_ON(!tclass || tclass >= ARRAY_SIZE(secclass_map))) |
778 | return -EINVAL; | |
779 | ||
48aab2f7 LT |
780 | if (!a) { |
781 | a = &stack_data; | |
50c205f5 | 782 | a->type = LSM_AUDIT_DATA_NONE; |
48aab2f7 LT |
783 | } |
784 | ||
899838b2 EP |
785 | sad.tclass = tclass; |
786 | sad.requested = requested; | |
787 | sad.ssid = ssid; | |
788 | sad.tsid = tsid; | |
789 | sad.audited = audited; | |
790 | sad.denied = denied; | |
ca7786a2 | 791 | sad.result = result; |
6b6bc620 | 792 | sad.state = state; |
899838b2 EP |
793 | |
794 | a->selinux_audit_data = &sad; | |
3f0882c4 | 795 | |
b61c37f5 | 796 | common_lsm_audit(a, avc_audit_pre_callback, avc_audit_post_callback); |
48aab2f7 LT |
797 | return 0; |
798 | } | |
799 | ||
1da177e4 LT |
800 | /** |
801 | * avc_add_callback - Register a callback for security events. | |
802 | * @callback: callback function | |
803 | * @events: security events | |
1da177e4 | 804 | * |
562c99f2 WG |
805 | * Register a callback function for events in the set @events. |
806 | * Returns %0 on success or -%ENOMEM if insufficient memory | |
807 | * exists to add the callback. | |
1da177e4 | 808 | */ |
562c99f2 | 809 | int __init avc_add_callback(int (*callback)(u32 event), u32 events) |
1da177e4 LT |
810 | { |
811 | struct avc_callback_node *c; | |
812 | int rc = 0; | |
813 | ||
0b36e44c | 814 | c = kmalloc(sizeof(*c), GFP_KERNEL); |
1da177e4 LT |
815 | if (!c) { |
816 | rc = -ENOMEM; | |
817 | goto out; | |
818 | } | |
819 | ||
820 | c->callback = callback; | |
821 | c->events = events; | |
1da177e4 LT |
822 | c->next = avc_callbacks; |
823 | avc_callbacks = c; | |
824 | out: | |
825 | return rc; | |
826 | } | |
827 | ||
1da177e4 | 828 | /** |
7cffc377 | 829 | * avc_update_node - Update an AVC entry |
e9fd7292 | 830 | * @avc: the access vector cache |
1da177e4 LT |
831 | * @event : Updating event |
832 | * @perms : Permission mask bits | |
e9fd7292 PM |
833 | * @driver: xperm driver information |
834 | * @xperm: xperm permissions | |
835 | * @ssid: AVC entry source sid | |
836 | * @tsid: AVC entry target sid | |
837 | * @tclass : AVC entry target object class | |
a5dda683 | 838 | * @seqno : sequence number when decision was made |
fa1aa143 | 839 | * @xpd: extended_perms_decision to be added to the node |
b17ec22f | 840 | * @flags: the AVC_* flags, e.g. AVC_EXTENDED_PERMS, or 0. |
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) { | |
030b995a | 898 | avc_node_kill(avc, node); |
fa1aa143 JVS |
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 |
e9fd7292 | 938 | * @avc: the access vector cache |
1da177e4 | 939 | */ |
6b6bc620 | 940 | static void avc_flush(struct selinux_avc *avc) |
1da177e4 | 941 | { |
26036651 | 942 | struct hlist_head *head; |
008574b1 | 943 | struct avc_node *node; |
edf3d1ae | 944 | spinlock_t *lock; |
008574b1 EP |
945 | unsigned long flag; |
946 | int i; | |
1da177e4 LT |
947 | |
948 | for (i = 0; i < AVC_CACHE_SLOTS; i++) { | |
6b6bc620 SS |
949 | head = &avc->avc_cache.slots[i]; |
950 | lock = &avc->avc_cache.slots_lock[i]; | |
edf3d1ae EP |
951 | |
952 | spin_lock_irqsave(lock, flag); | |
61844250 PM |
953 | /* |
954 | * With preemptable RCU, the outer spinlock does not | |
955 | * prevent RCU grace periods from ending. | |
956 | */ | |
957 | rcu_read_lock(); | |
b67bfe0d | 958 | hlist_for_each_entry(node, head, list) |
6b6bc620 | 959 | avc_node_delete(avc, node); |
61844250 | 960 | rcu_read_unlock(); |
edf3d1ae | 961 | spin_unlock_irqrestore(lock, flag); |
1da177e4 | 962 | } |
008574b1 EP |
963 | } |
964 | ||
965 | /** | |
966 | * avc_ss_reset - Flush the cache and revalidate migrated permissions. | |
e9fd7292 | 967 | * @avc: the access vector cache |
008574b1 EP |
968 | * @seqno: policy sequence number |
969 | */ | |
6b6bc620 | 970 | int avc_ss_reset(struct selinux_avc *avc, u32 seqno) |
008574b1 EP |
971 | { |
972 | struct avc_callback_node *c; | |
973 | int rc = 0, tmprc; | |
974 | ||
6b6bc620 | 975 | avc_flush(avc); |
1da177e4 LT |
976 | |
977 | for (c = avc_callbacks; c; c = c->next) { | |
978 | if (c->events & AVC_CALLBACK_RESET) { | |
562c99f2 | 979 | tmprc = c->callback(AVC_CALLBACK_RESET); |
376bd9cb DG |
980 | /* save the first error encountered for the return |
981 | value and continue processing the callbacks */ | |
982 | if (!rc) | |
983 | rc = tmprc; | |
1da177e4 LT |
984 | } |
985 | } | |
986 | ||
6b6bc620 | 987 | avc_latest_notif_update(avc, seqno, 0); |
1da177e4 LT |
988 | return rc; |
989 | } | |
990 | ||
a554bea8 LT |
991 | /* |
992 | * Slow-path helper function for avc_has_perm_noaudit, | |
993 | * when the avc_node lookup fails. We get called with | |
994 | * the RCU read lock held, and need to return with it | |
995 | * still held, but drop if for the security compute. | |
996 | * | |
997 | * Don't inline this, since it's the slow-path and just | |
998 | * results in a bigger stack frame. | |
999 | */ | |
6b6bc620 SS |
1000 | static noinline |
1001 | struct avc_node *avc_compute_av(struct selinux_state *state, | |
1002 | u32 ssid, u32 tsid, | |
1003 | u16 tclass, struct av_decision *avd, | |
1004 | struct avc_xperms_node *xp_node) | |
a554bea8 LT |
1005 | { |
1006 | rcu_read_unlock(); | |
fa1aa143 | 1007 | INIT_LIST_HEAD(&xp_node->xpd_head); |
6b6bc620 | 1008 | security_compute_av(state, ssid, tsid, tclass, avd, &xp_node->xp); |
a554bea8 | 1009 | rcu_read_lock(); |
6b6bc620 | 1010 | return avc_insert(state->avc, ssid, tsid, tclass, avd, xp_node); |
a554bea8 LT |
1011 | } |
1012 | ||
6b6bc620 SS |
1013 | static noinline int avc_denied(struct selinux_state *state, |
1014 | u32 ssid, u32 tsid, | |
1015 | u16 tclass, u32 requested, | |
1016 | u8 driver, u8 xperm, unsigned int flags, | |
1017 | struct av_decision *avd) | |
a554bea8 LT |
1018 | { |
1019 | if (flags & AVC_STRICT) | |
1020 | return -EACCES; | |
1021 | ||
6b6bc620 | 1022 | if (enforcing_enabled(state) && |
aa8e712c | 1023 | !(avd->flags & AVD_FLAGS_PERMISSIVE)) |
a554bea8 LT |
1024 | return -EACCES; |
1025 | ||
6b6bc620 SS |
1026 | avc_update_node(state->avc, AVC_CALLBACK_GRANT, requested, driver, |
1027 | xperm, ssid, tsid, tclass, avd->seqno, NULL, flags); | |
a554bea8 LT |
1028 | return 0; |
1029 | } | |
1030 | ||
fa1aa143 JVS |
1031 | /* |
1032 | * The avc extended permissions logic adds an additional 256 bits of | |
1033 | * permissions to an avc node when extended permissions for that node are | |
1034 | * specified in the avtab. If the additional 256 permissions is not adequate, | |
1035 | * as-is the case with ioctls, then multiple may be chained together and the | |
1036 | * driver field is used to specify which set contains the permission. | |
1037 | */ | |
6b6bc620 SS |
1038 | int avc_has_extended_perms(struct selinux_state *state, |
1039 | u32 ssid, u32 tsid, u16 tclass, u32 requested, | |
1040 | u8 driver, u8 xperm, struct common_audit_data *ad) | |
fa1aa143 JVS |
1041 | { |
1042 | struct avc_node *node; | |
1043 | struct av_decision avd; | |
1044 | u32 denied; | |
1045 | struct extended_perms_decision local_xpd; | |
1046 | struct extended_perms_decision *xpd = NULL; | |
1047 | struct extended_perms_data allowed; | |
1048 | struct extended_perms_data auditallow; | |
1049 | struct extended_perms_data dontaudit; | |
1050 | struct avc_xperms_node local_xp_node; | |
1051 | struct avc_xperms_node *xp_node; | |
1052 | int rc = 0, rc2; | |
1053 | ||
1054 | xp_node = &local_xp_node; | |
e6f2f381 OM |
1055 | if (WARN_ON(!requested)) |
1056 | return -EACCES; | |
fa1aa143 JVS |
1057 | |
1058 | rcu_read_lock(); | |
1059 | ||
6b6bc620 | 1060 | node = avc_lookup(state->avc, ssid, tsid, tclass); |
fa1aa143 | 1061 | if (unlikely(!node)) { |
0a9876f3 | 1062 | avc_compute_av(state, ssid, tsid, tclass, &avd, xp_node); |
fa1aa143 JVS |
1063 | } else { |
1064 | memcpy(&avd, &node->ae.avd, sizeof(avd)); | |
1065 | xp_node = node->ae.xp_node; | |
1066 | } | |
1067 | /* if extended permissions are not defined, only consider av_decision */ | |
1068 | if (!xp_node || !xp_node->xp.len) | |
1069 | goto decision; | |
1070 | ||
1071 | local_xpd.allowed = &allowed; | |
1072 | local_xpd.auditallow = &auditallow; | |
1073 | local_xpd.dontaudit = &dontaudit; | |
1074 | ||
1075 | xpd = avc_xperms_decision_lookup(driver, xp_node); | |
1076 | if (unlikely(!xpd)) { | |
1077 | /* | |
1078 | * Compute the extended_perms_decision only if the driver | |
1079 | * is flagged | |
1080 | */ | |
1081 | if (!security_xperm_test(xp_node->xp.drivers.p, driver)) { | |
1082 | avd.allowed &= ~requested; | |
1083 | goto decision; | |
1084 | } | |
1085 | rcu_read_unlock(); | |
6b6bc620 SS |
1086 | security_compute_xperms_decision(state, ssid, tsid, tclass, |
1087 | driver, &local_xpd); | |
fa1aa143 | 1088 | rcu_read_lock(); |
6b6bc620 SS |
1089 | avc_update_node(state->avc, AVC_CALLBACK_ADD_XPERMS, requested, |
1090 | driver, xperm, ssid, tsid, tclass, avd.seqno, | |
1091 | &local_xpd, 0); | |
fa1aa143 JVS |
1092 | } else { |
1093 | avc_quick_copy_xperms_decision(xperm, &local_xpd, xpd); | |
1094 | } | |
1095 | xpd = &local_xpd; | |
1096 | ||
1097 | if (!avc_xperms_has_perm(xpd, xperm, XPERMS_ALLOWED)) | |
1098 | avd.allowed &= ~requested; | |
1099 | ||
1100 | decision: | |
1101 | denied = requested & ~(avd.allowed); | |
1102 | if (unlikely(denied)) | |
6b6bc620 SS |
1103 | rc = avc_denied(state, ssid, tsid, tclass, requested, |
1104 | driver, xperm, AVC_EXTENDED_PERMS, &avd); | |
fa1aa143 JVS |
1105 | |
1106 | rcu_read_unlock(); | |
1107 | ||
6b6bc620 | 1108 | rc2 = avc_xperms_audit(state, ssid, tsid, tclass, requested, |
fa1aa143 JVS |
1109 | &avd, xpd, xperm, rc, ad); |
1110 | if (rc2) | |
1111 | return rc2; | |
1112 | return rc; | |
1113 | } | |
a554bea8 | 1114 | |
1da177e4 LT |
1115 | /** |
1116 | * avc_has_perm_noaudit - Check permissions but perform no auditing. | |
e9fd7292 | 1117 | * @state: SELinux state |
1da177e4 LT |
1118 | * @ssid: source security identifier |
1119 | * @tsid: target security identifier | |
1120 | * @tclass: target security class | |
1121 | * @requested: requested permissions, interpreted based on @tclass | |
b17ec22f | 1122 | * @flags: AVC_STRICT or 0 |
1da177e4 LT |
1123 | * @avd: access vector decisions |
1124 | * | |
1125 | * Check the AVC to determine whether the @requested permissions are granted | |
1126 | * for the SID pair (@ssid, @tsid), interpreting the permissions | |
1127 | * based on @tclass, and call the security server on a cache miss to obtain | |
1128 | * a new decision and add it to the cache. Return a copy of the decisions | |
1129 | * in @avd. Return %0 if all @requested permissions are granted, | |
1130 | * -%EACCES if any permissions are denied, or another -errno upon | |
1131 | * other errors. This function is typically called by avc_has_perm(), | |
1132 | * but may also be called directly to separate permission checking from | |
1133 | * auditing, e.g. in cases where a lock must be held for the check but | |
1134 | * should be released for the auditing. | |
1135 | */ | |
6b6bc620 SS |
1136 | inline int avc_has_perm_noaudit(struct selinux_state *state, |
1137 | u32 ssid, u32 tsid, | |
1138 | u16 tclass, u32 requested, | |
1139 | unsigned int flags, | |
1140 | struct av_decision *avd) | |
1da177e4 LT |
1141 | { |
1142 | struct avc_node *node; | |
fa1aa143 | 1143 | struct avc_xperms_node xp_node; |
1da177e4 LT |
1144 | int rc = 0; |
1145 | u32 denied; | |
1146 | ||
e6f2f381 OM |
1147 | if (WARN_ON(!requested)) |
1148 | return -EACCES; | |
eda4f69c | 1149 | |
1da177e4 LT |
1150 | rcu_read_lock(); |
1151 | ||
6b6bc620 | 1152 | node = avc_lookup(state->avc, ssid, tsid, tclass); |
83d4a806 | 1153 | if (unlikely(!node)) |
0a9876f3 | 1154 | avc_compute_av(state, ssid, tsid, tclass, avd, &xp_node); |
83d4a806 | 1155 | else |
f01e1af4 | 1156 | memcpy(avd, &node->ae.avd, sizeof(*avd)); |
1da177e4 | 1157 | |
21193dcd | 1158 | denied = requested & ~(avd->allowed); |
a554bea8 | 1159 | if (unlikely(denied)) |
6b6bc620 SS |
1160 | rc = avc_denied(state, ssid, tsid, tclass, requested, 0, 0, |
1161 | flags, avd); | |
1da177e4 LT |
1162 | |
1163 | rcu_read_unlock(); | |
1da177e4 LT |
1164 | return rc; |
1165 | } | |
1166 | ||
1167 | /** | |
1168 | * avc_has_perm - Check permissions and perform any appropriate auditing. | |
e9fd7292 | 1169 | * @state: SELinux state |
1da177e4 LT |
1170 | * @ssid: source security identifier |
1171 | * @tsid: target security identifier | |
1172 | * @tclass: target security class | |
1173 | * @requested: requested permissions, interpreted based on @tclass | |
1174 | * @auditdata: auxiliary audit data | |
1175 | * | |
1176 | * Check the AVC to determine whether the @requested permissions are granted | |
1177 | * for the SID pair (@ssid, @tsid), interpreting the permissions | |
1178 | * based on @tclass, and call the security server on a cache miss to obtain | |
1179 | * a new decision and add it to the cache. Audit the granting or denial of | |
1180 | * permissions in accordance with the policy. Return %0 if all @requested | |
1181 | * permissions are granted, -%EACCES if any permissions are denied, or | |
1182 | * another -errno upon other errors. | |
1183 | */ | |
6b6bc620 | 1184 | int avc_has_perm(struct selinux_state *state, u32 ssid, u32 tsid, u16 tclass, |
cb4fbe57 | 1185 | u32 requested, struct common_audit_data *auditdata) |
1da177e4 LT |
1186 | { |
1187 | struct av_decision avd; | |
9ade0cf4 | 1188 | int rc, rc2; |
1da177e4 | 1189 | |
6b6bc620 SS |
1190 | rc = avc_has_perm_noaudit(state, ssid, tsid, tclass, requested, 0, |
1191 | &avd); | |
9ade0cf4 | 1192 | |
6b6bc620 | 1193 | rc2 = avc_audit(state, ssid, tsid, tclass, requested, &avd, rc, |
d99cf13f | 1194 | auditdata); |
1a37079c SS |
1195 | if (rc2) |
1196 | return rc2; | |
1197 | return rc; | |
1198 | } | |
1199 | ||
6b6bc620 | 1200 | u32 avc_policy_seqno(struct selinux_state *state) |
788e7dd4 | 1201 | { |
6b6bc620 | 1202 | return state->avc->avc_cache.latest_notif; |
788e7dd4 | 1203 | } |
89c86576 TL |
1204 | |
1205 | void avc_disable(void) | |
1206 | { | |
5224ee08 EP |
1207 | /* |
1208 | * If you are looking at this because you have realized that we are | |
1209 | * not destroying the avc_node_cachep it might be easy to fix, but | |
1210 | * I don't know the memory barrier semantics well enough to know. It's | |
1211 | * possible that some other task dereferenced security_ops when | |
1212 | * it still pointed to selinux operations. If that is the case it's | |
1213 | * possible that it is about to use the avc and is about to need the | |
1214 | * avc_node_cachep. I know I could wrap the security.c security_ops call | |
1215 | * in an rcu_lock, but seriously, it's not worth it. Instead I just flush | |
1216 | * the cache and get that memory back. | |
1217 | */ | |
1218 | if (avc_node_cachep) { | |
6b6bc620 | 1219 | avc_flush(selinux_state.avc); |
5224ee08 EP |
1220 | /* kmem_cache_destroy(avc_node_cachep); */ |
1221 | } | |
89c86576 | 1222 | } |