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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Implementation of the kernel access vector cache (AVC).
3 *
4 * Authors: Stephen Smalley, <sds@epoch.ncsc.mil>
Eric Paris95fff332008-04-17 14:42:10 -04005 * James Morris <jmorris@redhat.com>
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
7 * Update: KaiGai, Kohei <kaigai@ak.jp.nec.com>
Eric Paris95fff332008-04-17 14:42:10 -04008 * Replaced the avc_lock spinlock by RCU.
Linus Torvalds1da177e2005-04-16 15:20:36 -07009 *
10 * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2,
Eric Paris95fff332008-04-17 14:42:10 -040014 * as published by the Free Software Foundation.
Linus Torvalds1da177e2005-04-16 15:20:36 -070015 */
16#include <linux/types.h>
17#include <linux/stddef.h>
18#include <linux/kernel.h>
19#include <linux/slab.h>
20#include <linux/fs.h>
21#include <linux/dcache.h>
22#include <linux/init.h>
23#include <linux/skbuff.h>
24#include <linux/percpu.h>
25#include <net/sock.h>
26#include <linux/un.h>
27#include <net/af_unix.h>
28#include <linux/ip.h>
29#include <linux/audit.h>
30#include <linux/ipv6.h>
31#include <net/ipv6.h>
32#include "avc.h"
33#include "avc_ss.h"
34
Chad Sellers5c458992006-11-06 12:38:16 -050035static const struct av_perm_to_string av_perm_to_string[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#define S_(c, v, s) { c, v, s },
37#include "av_perm_to_string.h"
38#undef S_
39};
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041static const char *class_to_string[] = {
42#define S_(s) s,
43#include "class_to_string.h"
44#undef S_
45};
Linus Torvalds1da177e2005-04-16 15:20:36 -070046
Eric Paris95fff332008-04-17 14:42:10 -040047#define TB_(s) static const char *s[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070048#define TE_(s) };
49#define S_(s) s,
50#include "common_perm_to_string.h"
51#undef TB_
52#undef TE_
53#undef S_
54
Chad Sellers5c458992006-11-06 12:38:16 -050055static const struct av_inherit av_inherit[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070056#define S_(c, i, b) { c, common_##i##_perm_to_string, b },
57#include "av_inherit.h"
58#undef S_
59};
60
Chad Sellers5c458992006-11-06 12:38:16 -050061const struct selinux_class_perm selinux_class_perm = {
62 av_perm_to_string,
63 ARRAY_SIZE(av_perm_to_string),
64 class_to_string,
65 ARRAY_SIZE(class_to_string),
66 av_inherit,
67 ARRAY_SIZE(av_inherit)
68};
69
Linus Torvalds1da177e2005-04-16 15:20:36 -070070#define AVC_CACHE_SLOTS 512
71#define AVC_DEF_CACHE_THRESHOLD 512
72#define AVC_CACHE_RECLAIM 16
73
74#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
Eric Paris95fff332008-04-17 14:42:10 -040075#define avc_cache_stats_incr(field) \
Linus Torvalds1da177e2005-04-16 15:20:36 -070076do { \
77 per_cpu(avc_cache_stats, get_cpu()).field++; \
78 put_cpu(); \
79} while (0)
80#else
81#define avc_cache_stats_incr(field) do {} while (0)
82#endif
83
84struct avc_entry {
85 u32 ssid;
86 u32 tsid;
87 u16 tclass;
88 struct av_decision avd;
89 atomic_t used; /* used recently */
90};
91
92struct avc_node {
93 struct avc_entry ae;
94 struct list_head list;
Eric Paris95fff332008-04-17 14:42:10 -040095 struct rcu_head rhead;
Linus Torvalds1da177e2005-04-16 15:20:36 -070096};
97
98struct avc_cache {
99 struct list_head slots[AVC_CACHE_SLOTS];
100 spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */
101 atomic_t lru_hint; /* LRU hint for reclaim scan */
102 atomic_t active_nodes;
103 u32 latest_notif; /* latest revocation notification */
104};
105
106struct avc_callback_node {
107 int (*callback) (u32 event, u32 ssid, u32 tsid,
Eric Paris95fff332008-04-17 14:42:10 -0400108 u16 tclass, u32 perms,
109 u32 *out_retained);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700110 u32 events;
111 u32 ssid;
112 u32 tsid;
113 u16 tclass;
114 u32 perms;
115 struct avc_callback_node *next;
116};
117
118/* Exported via selinufs */
119unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
120
121#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
122DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 };
123#endif
124
125static struct avc_cache avc_cache;
126static struct avc_callback_node *avc_callbacks;
Christoph Lametere18b8902006-12-06 20:33:20 -0800127static struct kmem_cache *avc_node_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128
129static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
130{
131 return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1);
132}
133
134/**
135 * avc_dump_av - Display an access vector in human-readable form.
136 * @tclass: target security class
137 * @av: access vector
138 */
139static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
140{
141 const char **common_pts = NULL;
142 u32 common_base = 0;
143 int i, i2, perm;
144
145 if (av == 0) {
146 audit_log_format(ab, " null");
147 return;
148 }
149
150 for (i = 0; i < ARRAY_SIZE(av_inherit); i++) {
151 if (av_inherit[i].tclass == tclass) {
152 common_pts = av_inherit[i].common_pts;
153 common_base = av_inherit[i].common_base;
154 break;
155 }
156 }
157
158 audit_log_format(ab, " {");
159 i = 0;
160 perm = 1;
161 while (perm < common_base) {
162 if (perm & av) {
163 audit_log_format(ab, " %s", common_pts[i]);
164 av &= ~perm;
165 }
166 i++;
167 perm <<= 1;
168 }
169
170 while (i < sizeof(av) * 8) {
171 if (perm & av) {
172 for (i2 = 0; i2 < ARRAY_SIZE(av_perm_to_string); i2++) {
173 if ((av_perm_to_string[i2].tclass == tclass) &&
174 (av_perm_to_string[i2].value == perm))
175 break;
176 }
177 if (i2 < ARRAY_SIZE(av_perm_to_string)) {
178 audit_log_format(ab, " %s",
179 av_perm_to_string[i2].name);
180 av &= ~perm;
181 }
182 }
183 i++;
184 perm <<= 1;
185 }
186
187 if (av)
188 audit_log_format(ab, " 0x%x", av);
189
190 audit_log_format(ab, " }");
191}
192
193/**
194 * avc_dump_query - Display a SID pair and a class in human-readable form.
195 * @ssid: source security identifier
196 * @tsid: target security identifier
197 * @tclass: target security class
198 */
199static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass)
200{
201 int rc;
202 char *scontext;
203 u32 scontext_len;
204
Eric Paris95fff332008-04-17 14:42:10 -0400205 rc = security_sid_to_context(ssid, &scontext, &scontext_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 if (rc)
207 audit_log_format(ab, "ssid=%d", ssid);
208 else {
209 audit_log_format(ab, "scontext=%s", scontext);
210 kfree(scontext);
211 }
212
213 rc = security_sid_to_context(tsid, &scontext, &scontext_len);
214 if (rc)
215 audit_log_format(ab, " tsid=%d", tsid);
216 else {
217 audit_log_format(ab, " tcontext=%s", scontext);
218 kfree(scontext);
219 }
Stephen Smalleya764ae42007-03-26 13:36:26 -0400220
221 BUG_ON(tclass >= ARRAY_SIZE(class_to_string) || !class_to_string[tclass]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700222 audit_log_format(ab, " tclass=%s", class_to_string[tclass]);
223}
224
225/**
226 * avc_init - Initialize the AVC.
227 *
228 * Initialize the access vector cache.
229 */
230void __init avc_init(void)
231{
232 int i;
233
234 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
235 INIT_LIST_HEAD(&avc_cache.slots[i]);
236 spin_lock_init(&avc_cache.slots_lock[i]);
237 }
238 atomic_set(&avc_cache.active_nodes, 0);
239 atomic_set(&avc_cache.lru_hint, 0);
240
241 avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node),
Paul Mundt20c2df82007-07-20 10:11:58 +0900242 0, SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243
David Woodhouse9ad9ad32005-06-22 15:04:33 +0100244 audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700245}
246
247int avc_get_hash_stats(char *page)
248{
249 int i, chain_len, max_chain_len, slots_used;
250 struct avc_node *node;
251
252 rcu_read_lock();
253
254 slots_used = 0;
255 max_chain_len = 0;
256 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
257 if (!list_empty(&avc_cache.slots[i])) {
258 slots_used++;
259 chain_len = 0;
260 list_for_each_entry_rcu(node, &avc_cache.slots[i], list)
261 chain_len++;
262 if (chain_len > max_chain_len)
263 max_chain_len = chain_len;
264 }
265 }
266
267 rcu_read_unlock();
268
269 return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
270 "longest chain: %d\n",
271 atomic_read(&avc_cache.active_nodes),
272 slots_used, AVC_CACHE_SLOTS, max_chain_len);
273}
274
275static void avc_node_free(struct rcu_head *rhead)
276{
277 struct avc_node *node = container_of(rhead, struct avc_node, rhead);
278 kmem_cache_free(avc_node_cachep, node);
279 avc_cache_stats_incr(frees);
280}
281
282static void avc_node_delete(struct avc_node *node)
283{
284 list_del_rcu(&node->list);
285 call_rcu(&node->rhead, avc_node_free);
286 atomic_dec(&avc_cache.active_nodes);
287}
288
289static void avc_node_kill(struct avc_node *node)
290{
291 kmem_cache_free(avc_node_cachep, node);
292 avc_cache_stats_incr(frees);
293 atomic_dec(&avc_cache.active_nodes);
294}
295
296static void avc_node_replace(struct avc_node *new, struct avc_node *old)
297{
298 list_replace_rcu(&old->list, &new->list);
299 call_rcu(&old->rhead, avc_node_free);
300 atomic_dec(&avc_cache.active_nodes);
301}
302
303static inline int avc_reclaim_node(void)
304{
305 struct avc_node *node;
306 int hvalue, try, ecx;
307 unsigned long flags;
308
Eric Paris95fff332008-04-17 14:42:10 -0400309 for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700310 hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);
311
312 if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))
313 continue;
314
Paul E. McKenney61844252008-04-21 18:12:33 -0700315 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316 list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
317 if (atomic_dec_and_test(&node->ae.used)) {
318 /* Recently Unused */
319 avc_node_delete(node);
320 avc_cache_stats_incr(reclaims);
321 ecx++;
322 if (ecx >= AVC_CACHE_RECLAIM) {
Paul E. McKenney61844252008-04-21 18:12:33 -0700323 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700324 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
325 goto out;
326 }
327 }
328 }
Paul E. McKenney61844252008-04-21 18:12:33 -0700329 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700330 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
331 }
332out:
333 return ecx;
334}
335
336static struct avc_node *avc_alloc_node(void)
337{
338 struct avc_node *node;
339
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800340 node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 if (!node)
342 goto out;
343
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 INIT_RCU_HEAD(&node->rhead);
345 INIT_LIST_HEAD(&node->list);
346 atomic_set(&node->ae.used, 1);
347 avc_cache_stats_incr(allocations);
348
349 if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
350 avc_reclaim_node();
351
352out:
353 return node;
354}
355
356static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
357{
358 node->ae.ssid = ssid;
359 node->ae.tsid = tsid;
360 node->ae.tclass = tclass;
361 memcpy(&node->ae.avd, &ae->avd, sizeof(node->ae.avd));
362}
363
364static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
365{
366 struct avc_node *node, *ret = NULL;
367 int hvalue;
368
369 hvalue = avc_hash(ssid, tsid, tclass);
370 list_for_each_entry_rcu(node, &avc_cache.slots[hvalue], list) {
371 if (ssid == node->ae.ssid &&
372 tclass == node->ae.tclass &&
373 tsid == node->ae.tsid) {
374 ret = node;
375 break;
376 }
377 }
378
379 if (ret == NULL) {
380 /* cache miss */
381 goto out;
382 }
383
384 /* cache hit */
385 if (atomic_read(&ret->ae.used) != 1)
386 atomic_set(&ret->ae.used, 1);
387out:
388 return ret;
389}
390
391/**
392 * avc_lookup - Look up an AVC entry.
393 * @ssid: source security identifier
394 * @tsid: target security identifier
395 * @tclass: target security class
396 * @requested: requested permissions, interpreted based on @tclass
397 *
398 * Look up an AVC entry that is valid for the
399 * @requested permissions between the SID pair
400 * (@ssid, @tsid), interpreting the permissions
401 * based on @tclass. If a valid AVC entry exists,
402 * then this function return the avc_node.
403 * Otherwise, this function returns NULL.
404 */
405static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass, u32 requested)
406{
407 struct avc_node *node;
408
409 avc_cache_stats_incr(lookups);
410 node = avc_search_node(ssid, tsid, tclass);
411
412 if (node && ((node->ae.avd.decided & requested) == requested)) {
413 avc_cache_stats_incr(hits);
414 goto out;
415 }
416
417 node = NULL;
418 avc_cache_stats_incr(misses);
419out:
420 return node;
421}
422
423static int avc_latest_notif_update(int seqno, int is_insert)
424{
425 int ret = 0;
426 static DEFINE_SPINLOCK(notif_lock);
427 unsigned long flag;
428
429 spin_lock_irqsave(&notif_lock, flag);
430 if (is_insert) {
431 if (seqno < avc_cache.latest_notif) {
Eric Paris744ba352008-04-17 11:52:44 -0400432 printk(KERN_WARNING "SELinux: avc: seqno %d < latest_notif %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700433 seqno, avc_cache.latest_notif);
434 ret = -EAGAIN;
435 }
436 } else {
437 if (seqno > avc_cache.latest_notif)
438 avc_cache.latest_notif = seqno;
439 }
440 spin_unlock_irqrestore(&notif_lock, flag);
441
442 return ret;
443}
444
445/**
446 * avc_insert - Insert an AVC entry.
447 * @ssid: source security identifier
448 * @tsid: target security identifier
449 * @tclass: target security class
450 * @ae: AVC entry
451 *
452 * Insert an AVC entry for the SID pair
453 * (@ssid, @tsid) and class @tclass.
454 * The access vectors and the sequence number are
455 * normally provided by the security server in
456 * response to a security_compute_av() call. If the
457 * sequence number @ae->avd.seqno is not less than the latest
458 * revocation notification, then the function copies
459 * the access vectors into a cache entry, returns
460 * avc_node inserted. Otherwise, this function returns NULL.
461 */
462static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
463{
464 struct avc_node *pos, *node = NULL;
465 int hvalue;
466 unsigned long flag;
467
468 if (avc_latest_notif_update(ae->avd.seqno, 1))
469 goto out;
470
471 node = avc_alloc_node();
472 if (node) {
473 hvalue = avc_hash(ssid, tsid, tclass);
474 avc_node_populate(node, ssid, tsid, tclass, ae);
475
476 spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
477 list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
478 if (pos->ae.ssid == ssid &&
479 pos->ae.tsid == tsid &&
480 pos->ae.tclass == tclass) {
Eric Paris95fff332008-04-17 14:42:10 -0400481 avc_node_replace(node, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 goto found;
483 }
484 }
485 list_add_rcu(&node->list, &avc_cache.slots[hvalue]);
486found:
487 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
488 }
489out:
490 return node;
491}
492
493static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
Alexey Dobriyanb5bf6c52005-09-03 15:55:17 -0700494 struct in6_addr *addr, __be16 port,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 char *name1, char *name2)
496{
497 if (!ipv6_addr_any(addr))
Joe Perches46b86a22006-01-13 14:29:07 -0800498 audit_log_format(ab, " %s=" NIP6_FMT, name1, NIP6(*addr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 if (port)
500 audit_log_format(ab, " %s=%d", name2, ntohs(port));
501}
502
Al Viro87fcd702006-12-04 22:00:55 +0000503static inline void avc_print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
Alexey Dobriyanb5bf6c52005-09-03 15:55:17 -0700504 __be16 port, char *name1, char *name2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505{
506 if (addr)
Joe Perches46b86a22006-01-13 14:29:07 -0800507 audit_log_format(ab, " %s=" NIPQUAD_FMT, name1, NIPQUAD(addr));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 if (port)
509 audit_log_format(ab, " %s=%d", name2, ntohs(port));
510}
511
512/**
513 * avc_audit - Audit the granting or denial of permissions.
514 * @ssid: source security identifier
515 * @tsid: target security identifier
516 * @tclass: target security class
517 * @requested: requested permissions
518 * @avd: access vector decisions
519 * @result: result from avc_has_perm_noaudit
520 * @a: auxiliary audit data
521 *
522 * Audit the granting or denial of permissions in accordance
523 * with the policy. This function is typically called by
524 * avc_has_perm() after a permission check, but can also be
525 * called directly by callers who use avc_has_perm_noaudit()
526 * in order to separate the permission check from the auditing.
527 * For example, this separation is useful when the permission check must
528 * be performed under a lock, to allow the lock to be released
529 * before calling the auditing code.
530 */
531void avc_audit(u32 ssid, u32 tsid,
Eric Paris95fff332008-04-17 14:42:10 -0400532 u16 tclass, u32 requested,
533 struct av_decision *avd, int result, struct avc_audit_data *a)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534{
David Woodhousecd77b822005-05-19 11:18:24 +0100535 struct task_struct *tsk = current;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536 struct inode *inode = NULL;
537 u32 denied, audited;
538 struct audit_buffer *ab;
539
540 denied = requested & ~avd->allowed;
541 if (denied) {
542 audited = denied;
543 if (!(audited & avd->auditdeny))
544 return;
545 } else if (result) {
546 audited = denied = requested;
Eric Paris95fff332008-04-17 14:42:10 -0400547 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 audited = requested;
549 if (!(audited & avd->auditallow))
550 return;
551 }
552
David Woodhouse9ad9ad32005-06-22 15:04:33 +0100553 ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 if (!ab)
555 return; /* audit_panic has been called */
556 audit_log_format(ab, "avc: %s ", denied ? "denied" : "granted");
Eric Paris95fff332008-04-17 14:42:10 -0400557 avc_dump_av(ab, tclass, audited);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 audit_log_format(ab, " for ");
David Woodhousecd77b822005-05-19 11:18:24 +0100559 if (a && a->tsk)
560 tsk = a->tsk;
David Woodhouse7b5d7812005-05-21 16:52:57 +0100561 if (tsk && tsk->pid) {
David Woodhousecd77b822005-05-19 11:18:24 +0100562 audit_log_format(ab, " pid=%d comm=", tsk->pid);
563 audit_log_untrustedstring(ab, tsk->comm);
564 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 if (a) {
566 switch (a->type) {
567 case AVC_AUDIT_DATA_IPC:
568 audit_log_format(ab, " key=%d", a->u.ipc_id);
569 break;
570 case AVC_AUDIT_DATA_CAP:
571 audit_log_format(ab, " capability=%d", a->u.cap);
572 break;
573 case AVC_AUDIT_DATA_FS:
Jan Blunck44707fd2008-02-14 19:38:33 -0800574 if (a->u.fs.path.dentry) {
575 struct dentry *dentry = a->u.fs.path.dentry;
576 if (a->u.fs.path.mnt) {
577 audit_log_d_path(ab, "path=",
578 &a->u.fs.path);
Al Viro4259fa02007-06-07 11:13:31 -0400579 } else {
580 audit_log_format(ab, " name=");
581 audit_log_untrustedstring(ab, dentry->d_name.name);
582 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 inode = dentry->d_inode;
584 } else if (a->u.fs.inode) {
585 struct dentry *dentry;
586 inode = a->u.fs.inode;
587 dentry = d_find_alias(inode);
588 if (dentry) {
Stephen Smalley37ca5382005-05-24 21:28:28 +0100589 audit_log_format(ab, " name=");
590 audit_log_untrustedstring(ab, dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700591 dput(dentry);
592 }
593 }
594 if (inode)
Tobias Oed13bddc22007-06-11 08:56:31 -0400595 audit_log_format(ab, " dev=%s ino=%lu",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 inode->i_sb->s_id,
597 inode->i_ino);
598 break;
599 case AVC_AUDIT_DATA_NET:
600 if (a->u.net.sk) {
601 struct sock *sk = a->u.net.sk;
602 struct unix_sock *u;
603 int len = 0;
604 char *p = NULL;
605
606 switch (sk->sk_family) {
607 case AF_INET: {
608 struct inet_sock *inet = inet_sk(sk);
609
610 avc_print_ipv4_addr(ab, inet->rcv_saddr,
611 inet->sport,
612 "laddr", "lport");
613 avc_print_ipv4_addr(ab, inet->daddr,
614 inet->dport,
615 "faddr", "fport");
616 break;
617 }
618 case AF_INET6: {
619 struct inet_sock *inet = inet_sk(sk);
620 struct ipv6_pinfo *inet6 = inet6_sk(sk);
621
622 avc_print_ipv6_addr(ab, &inet6->rcv_saddr,
623 inet->sport,
624 "laddr", "lport");
625 avc_print_ipv6_addr(ab, &inet6->daddr,
626 inet->dport,
627 "faddr", "fport");
628 break;
629 }
630 case AF_UNIX:
631 u = unix_sk(sk);
632 if (u->dentry) {
Jan Blunck44707fd2008-02-14 19:38:33 -0800633 struct path path = {
634 .dentry = u->dentry,
635 .mnt = u->mnt
636 };
Al Viro4259fa02007-06-07 11:13:31 -0400637 audit_log_d_path(ab, "path=",
Jan Blunck44707fd2008-02-14 19:38:33 -0800638 &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 break;
640 }
641 if (!u->addr)
642 break;
643 len = u->addr->len-sizeof(short);
644 p = &u->addr->name->sun_path[0];
Stephen Smalley37ca5382005-05-24 21:28:28 +0100645 audit_log_format(ab, " path=");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 if (*p)
Stephen Smalley37ca5382005-05-24 21:28:28 +0100647 audit_log_untrustedstring(ab, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 else
Stephen Smalley37ca5382005-05-24 21:28:28 +0100649 audit_log_hex(ab, p, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 break;
651 }
652 }
Eric Paris95fff332008-04-17 14:42:10 -0400653
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 switch (a->u.net.family) {
655 case AF_INET:
656 avc_print_ipv4_addr(ab, a->u.net.v4info.saddr,
657 a->u.net.sport,
658 "saddr", "src");
659 avc_print_ipv4_addr(ab, a->u.net.v4info.daddr,
660 a->u.net.dport,
661 "daddr", "dest");
662 break;
663 case AF_INET6:
664 avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr,
665 a->u.net.sport,
666 "saddr", "src");
667 avc_print_ipv6_addr(ab, &a->u.net.v6info.daddr,
668 a->u.net.dport,
669 "daddr", "dest");
670 break;
671 }
Paul Mooreda5645a2008-01-29 08:38:10 -0500672 if (a->u.net.netif > 0) {
673 struct net_device *dev;
674
675 /* NOTE: we always use init's namespace */
676 dev = dev_get_by_index(&init_net,
677 a->u.net.netif);
678 if (dev) {
679 audit_log_format(ab, " netif=%s",
680 dev->name);
681 dev_put(dev);
682 }
683 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 break;
685 }
686 }
687 audit_log_format(ab, " ");
688 avc_dump_query(ab, ssid, tsid, tclass);
689 audit_log_end(ab);
690}
691
692/**
693 * avc_add_callback - Register a callback for security events.
694 * @callback: callback function
695 * @events: security events
696 * @ssid: source security identifier or %SECSID_WILD
697 * @tsid: target security identifier or %SECSID_WILD
698 * @tclass: target security class
699 * @perms: permissions
700 *
701 * Register a callback function for events in the set @events
702 * related to the SID pair (@ssid, @tsid) and
703 * and the permissions @perms, interpreting
704 * @perms based on @tclass. Returns %0 on success or
705 * -%ENOMEM if insufficient memory exists to add the callback.
706 */
707int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
Eric Paris95fff332008-04-17 14:42:10 -0400708 u16 tclass, u32 perms,
709 u32 *out_retained),
710 u32 events, u32 ssid, u32 tsid,
711 u16 tclass, u32 perms)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712{
713 struct avc_callback_node *c;
714 int rc = 0;
715
716 c = kmalloc(sizeof(*c), GFP_ATOMIC);
717 if (!c) {
718 rc = -ENOMEM;
719 goto out;
720 }
721
722 c->callback = callback;
723 c->events = events;
724 c->ssid = ssid;
725 c->tsid = tsid;
726 c->perms = perms;
727 c->next = avc_callbacks;
728 avc_callbacks = c;
729out:
730 return rc;
731}
732
733static inline int avc_sidcmp(u32 x, u32 y)
734{
735 return (x == y || x == SECSID_WILD || y == SECSID_WILD);
736}
737
738/**
739 * avc_update_node Update an AVC entry
740 * @event : Updating event
741 * @perms : Permission mask bits
742 * @ssid,@tsid,@tclass : identifier of an AVC entry
743 *
744 * if a valid AVC entry doesn't exist,this function returns -ENOENT.
745 * if kmalloc() called internal returns NULL, this function returns -ENOMEM.
746 * otherwise, this function update the AVC entry. The original AVC-entry object
747 * will release later by RCU.
748 */
749static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass)
750{
751 int hvalue, rc = 0;
752 unsigned long flag;
753 struct avc_node *pos, *node, *orig = NULL;
754
755 node = avc_alloc_node();
756 if (!node) {
757 rc = -ENOMEM;
758 goto out;
759 }
760
761 /* Lock the target slot */
762 hvalue = avc_hash(ssid, tsid, tclass);
763 spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
764
Eric Paris95fff332008-04-17 14:42:10 -0400765 list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
766 if (ssid == pos->ae.ssid &&
767 tsid == pos->ae.tsid &&
768 tclass == pos->ae.tclass){
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 orig = pos;
770 break;
771 }
772 }
773
774 if (!orig) {
775 rc = -ENOENT;
776 avc_node_kill(node);
777 goto out_unlock;
778 }
779
780 /*
781 * Copy and replace original node.
782 */
783
784 avc_node_populate(node, ssid, tsid, tclass, &orig->ae);
785
786 switch (event) {
787 case AVC_CALLBACK_GRANT:
788 node->ae.avd.allowed |= perms;
789 break;
790 case AVC_CALLBACK_TRY_REVOKE:
791 case AVC_CALLBACK_REVOKE:
792 node->ae.avd.allowed &= ~perms;
793 break;
794 case AVC_CALLBACK_AUDITALLOW_ENABLE:
795 node->ae.avd.auditallow |= perms;
796 break;
797 case AVC_CALLBACK_AUDITALLOW_DISABLE:
798 node->ae.avd.auditallow &= ~perms;
799 break;
800 case AVC_CALLBACK_AUDITDENY_ENABLE:
801 node->ae.avd.auditdeny |= perms;
802 break;
803 case AVC_CALLBACK_AUDITDENY_DISABLE:
804 node->ae.avd.auditdeny &= ~perms;
805 break;
806 }
807 avc_node_replace(node, orig);
808out_unlock:
809 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
810out:
811 return rc;
812}
813
814/**
815 * avc_ss_reset - Flush the cache and revalidate migrated permissions.
816 * @seqno: policy sequence number
817 */
818int avc_ss_reset(u32 seqno)
819{
820 struct avc_callback_node *c;
Darrel Goeddel376bd9c2006-02-24 15:44:05 -0600821 int i, rc = 0, tmprc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822 unsigned long flag;
823 struct avc_node *node;
824
825 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
826 spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
Paul E. McKenney61844252008-04-21 18:12:33 -0700827 /*
828 * With preemptable RCU, the outer spinlock does not
829 * prevent RCU grace periods from ending.
830 */
831 rcu_read_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700832 list_for_each_entry(node, &avc_cache.slots[i], list)
833 avc_node_delete(node);
Paul E. McKenney61844252008-04-21 18:12:33 -0700834 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700835 spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
836 }
837
838 for (c = avc_callbacks; c; c = c->next) {
839 if (c->events & AVC_CALLBACK_RESET) {
Darrel Goeddel376bd9c2006-02-24 15:44:05 -0600840 tmprc = c->callback(AVC_CALLBACK_RESET,
Eric Paris95fff332008-04-17 14:42:10 -0400841 0, 0, 0, 0, NULL);
Darrel Goeddel376bd9c2006-02-24 15:44:05 -0600842 /* save the first error encountered for the return
843 value and continue processing the callbacks */
844 if (!rc)
845 rc = tmprc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700846 }
847 }
848
849 avc_latest_notif_update(seqno, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700850 return rc;
851}
852
853/**
854 * avc_has_perm_noaudit - Check permissions but perform no auditing.
855 * @ssid: source security identifier
856 * @tsid: target security identifier
857 * @tclass: target security class
858 * @requested: requested permissions, interpreted based on @tclass
Stephen Smalley2c3c05d2007-06-07 15:34:10 -0400859 * @flags: AVC_STRICT or 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700860 * @avd: access vector decisions
861 *
862 * Check the AVC to determine whether the @requested permissions are granted
863 * for the SID pair (@ssid, @tsid), interpreting the permissions
864 * based on @tclass, and call the security server on a cache miss to obtain
865 * a new decision and add it to the cache. Return a copy of the decisions
866 * in @avd. Return %0 if all @requested permissions are granted,
867 * -%EACCES if any permissions are denied, or another -errno upon
868 * other errors. This function is typically called by avc_has_perm(),
869 * but may also be called directly to separate permission checking from
870 * auditing, e.g. in cases where a lock must be held for the check but
871 * should be released for the auditing.
872 */
873int avc_has_perm_noaudit(u32 ssid, u32 tsid,
Stephen Smalley2c3c05d2007-06-07 15:34:10 -0400874 u16 tclass, u32 requested,
875 unsigned flags,
876 struct av_decision *avd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700877{
878 struct avc_node *node;
879 struct avc_entry entry, *p_ae;
880 int rc = 0;
881 u32 denied;
882
Eric Pariseda4f692008-03-11 14:19:34 -0400883 BUG_ON(!requested);
884
Linus Torvalds1da177e2005-04-16 15:20:36 -0700885 rcu_read_lock();
886
887 node = avc_lookup(ssid, tsid, tclass, requested);
888 if (!node) {
889 rcu_read_unlock();
Eric Paris95fff332008-04-17 14:42:10 -0400890 rc = security_compute_av(ssid, tsid, tclass, requested, &entry.avd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891 if (rc)
892 goto out;
893 rcu_read_lock();
Eric Paris95fff332008-04-17 14:42:10 -0400894 node = avc_insert(ssid, tsid, tclass, &entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895 }
896
897 p_ae = node ? &node->ae : &entry;
898
899 if (avd)
900 memcpy(avd, &p_ae->avd, sizeof(*avd));
901
902 denied = requested & ~(p_ae->avd.allowed);
903
Eric Pariseda4f692008-03-11 14:19:34 -0400904 if (denied) {
Eric Paris64dbf072008-03-31 12:17:33 +1100905 if (flags & AVC_STRICT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 rc = -EACCES;
Eric Paris64dbf072008-03-31 12:17:33 +1100907 else if (!selinux_enforcing || security_permissive_sid(ssid))
908 avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,
909 tsid, tclass);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700910 else
Eric Paris64dbf072008-03-31 12:17:33 +1100911 rc = -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700912 }
913
914 rcu_read_unlock();
915out:
916 return rc;
917}
918
919/**
920 * avc_has_perm - Check permissions and perform any appropriate auditing.
921 * @ssid: source security identifier
922 * @tsid: target security identifier
923 * @tclass: target security class
924 * @requested: requested permissions, interpreted based on @tclass
925 * @auditdata: auxiliary audit data
926 *
927 * Check the AVC to determine whether the @requested permissions are granted
928 * for the SID pair (@ssid, @tsid), interpreting the permissions
929 * based on @tclass, and call the security server on a cache miss to obtain
930 * a new decision and add it to the cache. Audit the granting or denial of
931 * permissions in accordance with the policy. Return %0 if all @requested
932 * permissions are granted, -%EACCES if any permissions are denied, or
933 * another -errno upon other errors.
934 */
935int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
Eric Paris95fff332008-04-17 14:42:10 -0400936 u32 requested, struct avc_audit_data *auditdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700937{
938 struct av_decision avd;
939 int rc;
940
Stephen Smalley2c3c05d2007-06-07 15:34:10 -0400941 rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942 avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
943 return rc;
944}
Yuichi Nakamura788e7dd2007-09-14 09:27:07 +0900945
946u32 avc_policy_seqno(void)
947{
948 return avc_cache.latest_notif;
949}