aboutsummaryrefslogtreecommitdiffstats
path: root/security/selinux/avc.c
diff options
context:
space:
mode:
Diffstat (limited to 'security/selinux/avc.c')
-rw-r--r--security/selinux/avc.c949
1 files changed, 949 insertions, 0 deletions
diff --git a/security/selinux/avc.c b/security/selinux/avc.c
new file mode 100644
index 000000000000..fe6285e5c68f
--- /dev/null
+++ b/security/selinux/avc.c
@@ -0,0 +1,949 @@
1/*
2 * Implementation of the kernel access vector cache (AVC).
3 *
4 * Authors: Stephen Smalley, <sds@epoch.ncsc.mil>
5 * James Morris <jmorris@redhat.com>
6 *
7 * Update: KaiGai, Kohei <kaigai@ak.jp.nec.com>
8 * Replaced the avc_lock spinlock by RCU.
9 *
10 * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
11 *
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License version 2,
14 * as published by the Free Software Foundation.
15 */
16#include <linux/types.h>
17#include <linux/stddef.h>
18#include <linux/kernel.h>
19#include <linux/slab.h>
20#include <linux/fs.h>
21#include <linux/dcache.h>
22#include <linux/init.h>
23#include <linux/skbuff.h>
24#include <linux/percpu.h>
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
35static const struct av_perm_to_string
36{
37 u16 tclass;
38 u32 value;
39 const char *name;
40} av_perm_to_string[] = {
41#define S_(c, v, s) { c, v, s },
42#include "av_perm_to_string.h"
43#undef S_
44};
45
46#ifdef CONFIG_AUDIT
47static const char *class_to_string[] = {
48#define S_(s) s,
49#include "class_to_string.h"
50#undef S_
51};
52#endif
53
54#define TB_(s) static const char * s [] = {
55#define TE_(s) };
56#define S_(s) s,
57#include "common_perm_to_string.h"
58#undef TB_
59#undef TE_
60#undef S_
61
62static const struct av_inherit
63{
64 u16 tclass;
65 const char **common_pts;
66 u32 common_base;
67} av_inherit[] = {
68#define S_(c, i, b) { c, common_##i##_perm_to_string, b },
69#include "av_inherit.h"
70#undef S_
71};
72
73#define AVC_CACHE_SLOTS 512
74#define AVC_DEF_CACHE_THRESHOLD 512
75#define AVC_CACHE_RECLAIM 16
76
77#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
78#define avc_cache_stats_incr(field) \
79do { \
80 per_cpu(avc_cache_stats, get_cpu()).field++; \
81 put_cpu(); \
82} while (0)
83#else
84#define avc_cache_stats_incr(field) do {} while (0)
85#endif
86
87struct avc_entry {
88 u32 ssid;
89 u32 tsid;
90 u16 tclass;
91 struct av_decision avd;
92 atomic_t used; /* used recently */
93};
94
95struct avc_node {
96 struct avc_entry ae;
97 struct list_head list;
98 struct rcu_head rhead;
99};
100
101struct avc_cache {
102 struct list_head slots[AVC_CACHE_SLOTS];
103 spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */
104 atomic_t lru_hint; /* LRU hint for reclaim scan */
105 atomic_t active_nodes;
106 u32 latest_notif; /* latest revocation notification */
107};
108
109struct avc_callback_node {
110 int (*callback) (u32 event, u32 ssid, u32 tsid,
111 u16 tclass, u32 perms,
112 u32 *out_retained);
113 u32 events;
114 u32 ssid;
115 u32 tsid;
116 u16 tclass;
117 u32 perms;
118 struct avc_callback_node *next;
119};
120
121/* Exported via selinufs */
122unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
123
124#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
125DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 };
126#endif
127
128static struct avc_cache avc_cache;
129static struct avc_callback_node *avc_callbacks;
130static kmem_cache_t *avc_node_cachep;
131
132static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
133{
134 return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1);
135}
136
137/**
138 * avc_dump_av - Display an access vector in human-readable form.
139 * @tclass: target security class
140 * @av: access vector
141 */
142static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
143{
144 const char **common_pts = NULL;
145 u32 common_base = 0;
146 int i, i2, perm;
147
148 if (av == 0) {
149 audit_log_format(ab, " null");
150 return;
151 }
152
153 for (i = 0; i < ARRAY_SIZE(av_inherit); i++) {
154 if (av_inherit[i].tclass == tclass) {
155 common_pts = av_inherit[i].common_pts;
156 common_base = av_inherit[i].common_base;
157 break;
158 }
159 }
160
161 audit_log_format(ab, " {");
162 i = 0;
163 perm = 1;
164 while (perm < common_base) {
165 if (perm & av) {
166 audit_log_format(ab, " %s", common_pts[i]);
167 av &= ~perm;
168 }
169 i++;
170 perm <<= 1;
171 }
172
173 while (i < sizeof(av) * 8) {
174 if (perm & av) {
175 for (i2 = 0; i2 < ARRAY_SIZE(av_perm_to_string); i2++) {
176 if ((av_perm_to_string[i2].tclass == tclass) &&
177 (av_perm_to_string[i2].value == perm))
178 break;
179 }
180 if (i2 < ARRAY_SIZE(av_perm_to_string)) {
181 audit_log_format(ab, " %s",
182 av_perm_to_string[i2].name);
183 av &= ~perm;
184 }
185 }
186 i++;
187 perm <<= 1;
188 }
189
190 if (av)
191 audit_log_format(ab, " 0x%x", av);
192
193 audit_log_format(ab, " }");
194}
195
196/**
197 * avc_dump_query - Display a SID pair and a class in human-readable form.
198 * @ssid: source security identifier
199 * @tsid: target security identifier
200 * @tclass: target security class
201 */
202static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass)
203{
204 int rc;
205 char *scontext;
206 u32 scontext_len;
207
208 rc = security_sid_to_context(ssid, &scontext, &scontext_len);
209 if (rc)
210 audit_log_format(ab, "ssid=%d", ssid);
211 else {
212 audit_log_format(ab, "scontext=%s", scontext);
213 kfree(scontext);
214 }
215
216 rc = security_sid_to_context(tsid, &scontext, &scontext_len);
217 if (rc)
218 audit_log_format(ab, " tsid=%d", tsid);
219 else {
220 audit_log_format(ab, " tcontext=%s", scontext);
221 kfree(scontext);
222 }
223 audit_log_format(ab, " tclass=%s", class_to_string[tclass]);
224}
225
226/**
227 * avc_init - Initialize the AVC.
228 *
229 * Initialize the access vector cache.
230 */
231void __init avc_init(void)
232{
233 int i;
234
235 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
236 INIT_LIST_HEAD(&avc_cache.slots[i]);
237 spin_lock_init(&avc_cache.slots_lock[i]);
238 }
239 atomic_set(&avc_cache.active_nodes, 0);
240 atomic_set(&avc_cache.lru_hint, 0);
241
242 avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node),
243 0, SLAB_PANIC, NULL, NULL);
244
245 audit_log(current->audit_context, "AVC INITIALIZED\n");
246}
247
248int avc_get_hash_stats(char *page)
249{
250 int i, chain_len, max_chain_len, slots_used;
251 struct avc_node *node;
252
253 rcu_read_lock();
254
255 slots_used = 0;
256 max_chain_len = 0;
257 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
258 if (!list_empty(&avc_cache.slots[i])) {
259 slots_used++;
260 chain_len = 0;
261 list_for_each_entry_rcu(node, &avc_cache.slots[i], list)
262 chain_len++;
263 if (chain_len > max_chain_len)
264 max_chain_len = chain_len;
265 }
266 }
267
268 rcu_read_unlock();
269
270 return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
271 "longest chain: %d\n",
272 atomic_read(&avc_cache.active_nodes),
273 slots_used, AVC_CACHE_SLOTS, max_chain_len);
274}
275
276static void avc_node_free(struct rcu_head *rhead)
277{
278 struct avc_node *node = container_of(rhead, struct avc_node, rhead);
279 kmem_cache_free(avc_node_cachep, node);
280 avc_cache_stats_incr(frees);
281}
282
283static void avc_node_delete(struct avc_node *node)
284{
285 list_del_rcu(&node->list);
286 call_rcu(&node->rhead, avc_node_free);
287 atomic_dec(&avc_cache.active_nodes);
288}
289
290static void avc_node_kill(struct avc_node *node)
291{
292 kmem_cache_free(avc_node_cachep, node);
293 avc_cache_stats_incr(frees);
294 atomic_dec(&avc_cache.active_nodes);
295}
296
297static void avc_node_replace(struct avc_node *new, struct avc_node *old)
298{
299 list_replace_rcu(&old->list, &new->list);
300 call_rcu(&old->rhead, avc_node_free);
301 atomic_dec(&avc_cache.active_nodes);
302}
303
304static inline int avc_reclaim_node(void)
305{
306 struct avc_node *node;
307 int hvalue, try, ecx;
308 unsigned long flags;
309
310 for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++ ) {
311 hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);
312
313 if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))
314 continue;
315
316 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) {
323 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
324 goto out;
325 }
326 }
327 }
328 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
329 }
330out:
331 return ecx;
332}
333
334static struct avc_node *avc_alloc_node(void)
335{
336 struct avc_node *node;
337
338 node = kmem_cache_alloc(avc_node_cachep, SLAB_ATOMIC);
339 if (!node)
340 goto out;
341
342 memset(node, 0, sizeof(*node));
343 INIT_RCU_HEAD(&node->rhead);
344 INIT_LIST_HEAD(&node->list);
345 atomic_set(&node->ae.used, 1);
346 avc_cache_stats_incr(allocations);
347
348 if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
349 avc_reclaim_node();
350
351out:
352 return node;
353}
354
355static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
356{
357 node->ae.ssid = ssid;
358 node->ae.tsid = tsid;
359 node->ae.tclass = tclass;
360 memcpy(&node->ae.avd, &ae->avd, sizeof(node->ae.avd));
361}
362
363static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
364{
365 struct avc_node *node, *ret = NULL;
366 int hvalue;
367
368 hvalue = avc_hash(ssid, tsid, tclass);
369 list_for_each_entry_rcu(node, &avc_cache.slots[hvalue], list) {
370 if (ssid == node->ae.ssid &&
371 tclass == node->ae.tclass &&
372 tsid == node->ae.tsid) {
373 ret = node;
374 break;
375 }
376 }
377
378 if (ret == NULL) {
379 /* cache miss */
380 goto out;
381 }
382
383 /* cache hit */
384 if (atomic_read(&ret->ae.used) != 1)
385 atomic_set(&ret->ae.used, 1);
386out:
387 return ret;
388}
389
390/**
391 * avc_lookup - Look up an AVC entry.
392 * @ssid: source security identifier
393 * @tsid: target security identifier
394 * @tclass: target security class
395 * @requested: requested permissions, interpreted based on @tclass
396 *
397 * Look up an AVC entry that is valid for the
398 * @requested permissions between the SID pair
399 * (@ssid, @tsid), interpreting the permissions
400 * based on @tclass. If a valid AVC entry exists,
401 * then this function return the avc_node.
402 * Otherwise, this function returns NULL.
403 */
404static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass, u32 requested)
405{
406 struct avc_node *node;
407
408 avc_cache_stats_incr(lookups);
409 node = avc_search_node(ssid, tsid, tclass);
410
411 if (node && ((node->ae.avd.decided & requested) == requested)) {
412 avc_cache_stats_incr(hits);
413 goto out;
414 }
415
416 node = NULL;
417 avc_cache_stats_incr(misses);
418out:
419 return node;
420}
421
422static int avc_latest_notif_update(int seqno, int is_insert)
423{
424 int ret = 0;
425 static DEFINE_SPINLOCK(notif_lock);
426 unsigned long flag;
427
428 spin_lock_irqsave(&notif_lock, flag);
429 if (is_insert) {
430 if (seqno < avc_cache.latest_notif) {
431 printk(KERN_WARNING "avc: seqno %d < latest_notif %d\n",
432 seqno, avc_cache.latest_notif);
433 ret = -EAGAIN;
434 }
435 } else {
436 if (seqno > avc_cache.latest_notif)
437 avc_cache.latest_notif = seqno;
438 }
439 spin_unlock_irqrestore(&notif_lock, flag);
440
441 return ret;
442}
443
444/**
445 * avc_insert - Insert an AVC entry.
446 * @ssid: source security identifier
447 * @tsid: target security identifier
448 * @tclass: target security class
449 * @ae: AVC entry
450 *
451 * Insert an AVC entry for the SID pair
452 * (@ssid, @tsid) and class @tclass.
453 * The access vectors and the sequence number are
454 * normally provided by the security server in
455 * response to a security_compute_av() call. If the
456 * sequence number @ae->avd.seqno is not less than the latest
457 * revocation notification, then the function copies
458 * the access vectors into a cache entry, returns
459 * avc_node inserted. Otherwise, this function returns NULL.
460 */
461static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
462{
463 struct avc_node *pos, *node = NULL;
464 int hvalue;
465 unsigned long flag;
466
467 if (avc_latest_notif_update(ae->avd.seqno, 1))
468 goto out;
469
470 node = avc_alloc_node();
471 if (node) {
472 hvalue = avc_hash(ssid, tsid, tclass);
473 avc_node_populate(node, ssid, tsid, tclass, ae);
474
475 spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
476 list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
477 if (pos->ae.ssid == ssid &&
478 pos->ae.tsid == tsid &&
479 pos->ae.tclass == tclass) {
480 avc_node_replace(node, pos);
481 goto found;
482 }
483 }
484 list_add_rcu(&node->list, &avc_cache.slots[hvalue]);
485found:
486 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
487 }
488out:
489 return node;
490}
491
492static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
493 struct in6_addr *addr, u16 port,
494 char *name1, char *name2)
495{
496 if (!ipv6_addr_any(addr))
497 audit_log_format(ab, " %s=%04x:%04x:%04x:%04x:%04x:"
498 "%04x:%04x:%04x", name1, NIP6(*addr));
499 if (port)
500 audit_log_format(ab, " %s=%d", name2, ntohs(port));
501}
502
503static inline void avc_print_ipv4_addr(struct audit_buffer *ab, u32 addr,
504 u16 port, char *name1, char *name2)
505{
506 if (addr)
507 audit_log_format(ab, " %s=%d.%d.%d.%d", name1, NIPQUAD(addr));
508 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,
532 u16 tclass, u32 requested,
533 struct av_decision *avd, int result, struct avc_audit_data *a)
534{
535 struct task_struct *tsk = current;
536 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;
547 } else {
548 audited = requested;
549 if (!(audited & avd->auditallow))
550 return;
551 }
552
553 ab = audit_log_start(current->audit_context);
554 if (!ab)
555 return; /* audit_panic has been called */
556 audit_log_format(ab, "avc: %s ", denied ? "denied" : "granted");
557 avc_dump_av(ab, tclass,audited);
558 audit_log_format(ab, " for ");
559 if (a && a->tsk)
560 tsk = a->tsk;
561 if (tsk && tsk->pid) {
562 struct mm_struct *mm;
563 struct vm_area_struct *vma;
564 audit_log_format(ab, " pid=%d", tsk->pid);
565 if (tsk == current)
566 mm = current->mm;
567 else
568 mm = get_task_mm(tsk);
569 if (mm) {
570 if (down_read_trylock(&mm->mmap_sem)) {
571 vma = mm->mmap;
572 while (vma) {
573 if ((vma->vm_flags & VM_EXECUTABLE) &&
574 vma->vm_file) {
575 audit_log_d_path(ab, "exe=",
576 vma->vm_file->f_dentry,
577 vma->vm_file->f_vfsmnt);
578 break;
579 }
580 vma = vma->vm_next;
581 }
582 up_read(&mm->mmap_sem);
583 } else {
584 audit_log_format(ab, " comm=%s", tsk->comm);
585 }
586 if (tsk != current)
587 mmput(mm);
588 } else {
589 audit_log_format(ab, " comm=%s", tsk->comm);
590 }
591 }
592 if (a) {
593 switch (a->type) {
594 case AVC_AUDIT_DATA_IPC:
595 audit_log_format(ab, " key=%d", a->u.ipc_id);
596 break;
597 case AVC_AUDIT_DATA_CAP:
598 audit_log_format(ab, " capability=%d", a->u.cap);
599 break;
600 case AVC_AUDIT_DATA_FS:
601 if (a->u.fs.dentry) {
602 struct dentry *dentry = a->u.fs.dentry;
603 if (a->u.fs.mnt) {
604 audit_log_d_path(ab, "path=", dentry,
605 a->u.fs.mnt);
606 } else {
607 audit_log_format(ab, " name=%s",
608 dentry->d_name.name);
609 }
610 inode = dentry->d_inode;
611 } else if (a->u.fs.inode) {
612 struct dentry *dentry;
613 inode = a->u.fs.inode;
614 dentry = d_find_alias(inode);
615 if (dentry) {
616 audit_log_format(ab, " name=%s",
617 dentry->d_name.name);
618 dput(dentry);
619 }
620 }
621 if (inode)
622 audit_log_format(ab, " dev=%s ino=%ld",
623 inode->i_sb->s_id,
624 inode->i_ino);
625 break;
626 case AVC_AUDIT_DATA_NET:
627 if (a->u.net.sk) {
628 struct sock *sk = a->u.net.sk;
629 struct unix_sock *u;
630 int len = 0;
631 char *p = NULL;
632
633 switch (sk->sk_family) {
634 case AF_INET: {
635 struct inet_sock *inet = inet_sk(sk);
636
637 avc_print_ipv4_addr(ab, inet->rcv_saddr,
638 inet->sport,
639 "laddr", "lport");
640 avc_print_ipv4_addr(ab, inet->daddr,
641 inet->dport,
642 "faddr", "fport");
643 break;
644 }
645 case AF_INET6: {
646 struct inet_sock *inet = inet_sk(sk);
647 struct ipv6_pinfo *inet6 = inet6_sk(sk);
648
649 avc_print_ipv6_addr(ab, &inet6->rcv_saddr,
650 inet->sport,
651 "laddr", "lport");
652 avc_print_ipv6_addr(ab, &inet6->daddr,
653 inet->dport,
654 "faddr", "fport");
655 break;
656 }
657 case AF_UNIX:
658 u = unix_sk(sk);
659 if (u->dentry) {
660 audit_log_d_path(ab, "path=",
661 u->dentry, u->mnt);
662 break;
663 }
664 if (!u->addr)
665 break;
666 len = u->addr->len-sizeof(short);
667 p = &u->addr->name->sun_path[0];
668 if (*p)
669 audit_log_format(ab,
670 "path=%*.*s", len,
671 len, p);
672 else
673 audit_log_format(ab,
674 "path=@%*.*s", len-1,
675 len-1, p+1);
676 break;
677 }
678 }
679
680 switch (a->u.net.family) {
681 case AF_INET:
682 avc_print_ipv4_addr(ab, a->u.net.v4info.saddr,
683 a->u.net.sport,
684 "saddr", "src");
685 avc_print_ipv4_addr(ab, a->u.net.v4info.daddr,
686 a->u.net.dport,
687 "daddr", "dest");
688 break;
689 case AF_INET6:
690 avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr,
691 a->u.net.sport,
692 "saddr", "src");
693 avc_print_ipv6_addr(ab, &a->u.net.v6info.daddr,
694 a->u.net.dport,
695 "daddr", "dest");
696 break;
697 }
698 if (a->u.net.netif)
699 audit_log_format(ab, " netif=%s",
700 a->u.net.netif);
701 break;
702 }
703 }
704 audit_log_format(ab, " ");
705 avc_dump_query(ab, ssid, tsid, tclass);
706 audit_log_end(ab);
707}
708
709/**
710 * avc_add_callback - Register a callback for security events.
711 * @callback: callback function
712 * @events: security events
713 * @ssid: source security identifier or %SECSID_WILD
714 * @tsid: target security identifier or %SECSID_WILD
715 * @tclass: target security class
716 * @perms: permissions
717 *
718 * Register a callback function for events in the set @events
719 * related to the SID pair (@ssid, @tsid) and
720 * and the permissions @perms, interpreting
721 * @perms based on @tclass. Returns %0 on success or
722 * -%ENOMEM if insufficient memory exists to add the callback.
723 */
724int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
725 u16 tclass, u32 perms,
726 u32 *out_retained),
727 u32 events, u32 ssid, u32 tsid,
728 u16 tclass, u32 perms)
729{
730 struct avc_callback_node *c;
731 int rc = 0;
732
733 c = kmalloc(sizeof(*c), GFP_ATOMIC);
734 if (!c) {
735 rc = -ENOMEM;
736 goto out;
737 }
738
739 c->callback = callback;
740 c->events = events;
741 c->ssid = ssid;
742 c->tsid = tsid;
743 c->perms = perms;
744 c->next = avc_callbacks;
745 avc_callbacks = c;
746out:
747 return rc;
748}
749
750static inline int avc_sidcmp(u32 x, u32 y)
751{
752 return (x == y || x == SECSID_WILD || y == SECSID_WILD);
753}
754
755/**
756 * avc_update_node Update an AVC entry
757 * @event : Updating event
758 * @perms : Permission mask bits
759 * @ssid,@tsid,@tclass : identifier of an AVC entry
760 *
761 * if a valid AVC entry doesn't exist,this function returns -ENOENT.
762 * if kmalloc() called internal returns NULL, this function returns -ENOMEM.
763 * otherwise, this function update the AVC entry. The original AVC-entry object
764 * will release later by RCU.
765 */
766static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass)
767{
768 int hvalue, rc = 0;
769 unsigned long flag;
770 struct avc_node *pos, *node, *orig = NULL;
771
772 node = avc_alloc_node();
773 if (!node) {
774 rc = -ENOMEM;
775 goto out;
776 }
777
778 /* Lock the target slot */
779 hvalue = avc_hash(ssid, tsid, tclass);
780 spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
781
782 list_for_each_entry(pos, &avc_cache.slots[hvalue], list){
783 if ( ssid==pos->ae.ssid &&
784 tsid==pos->ae.tsid &&
785 tclass==pos->ae.tclass ){
786 orig = pos;
787 break;
788 }
789 }
790
791 if (!orig) {
792 rc = -ENOENT;
793 avc_node_kill(node);
794 goto out_unlock;
795 }
796
797 /*
798 * Copy and replace original node.
799 */
800
801 avc_node_populate(node, ssid, tsid, tclass, &orig->ae);
802
803 switch (event) {
804 case AVC_CALLBACK_GRANT:
805 node->ae.avd.allowed |= perms;
806 break;
807 case AVC_CALLBACK_TRY_REVOKE:
808 case AVC_CALLBACK_REVOKE:
809 node->ae.avd.allowed &= ~perms;
810 break;
811 case AVC_CALLBACK_AUDITALLOW_ENABLE:
812 node->ae.avd.auditallow |= perms;
813 break;
814 case AVC_CALLBACK_AUDITALLOW_DISABLE:
815 node->ae.avd.auditallow &= ~perms;
816 break;
817 case AVC_CALLBACK_AUDITDENY_ENABLE:
818 node->ae.avd.auditdeny |= perms;
819 break;
820 case AVC_CALLBACK_AUDITDENY_DISABLE:
821 node->ae.avd.auditdeny &= ~perms;
822 break;
823 }
824 avc_node_replace(node, orig);
825out_unlock:
826 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
827out:
828 return rc;
829}
830
831/**
832 * avc_ss_reset - Flush the cache and revalidate migrated permissions.
833 * @seqno: policy sequence number
834 */
835int avc_ss_reset(u32 seqno)
836{
837 struct avc_callback_node *c;
838 int i, rc = 0;
839 unsigned long flag;
840 struct avc_node *node;
841
842 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
843 spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
844 list_for_each_entry(node, &avc_cache.slots[i], list)
845 avc_node_delete(node);
846 spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
847 }
848
849 for (c = avc_callbacks; c; c = c->next) {
850 if (c->events & AVC_CALLBACK_RESET) {
851 rc = c->callback(AVC_CALLBACK_RESET,
852 0, 0, 0, 0, NULL);
853 if (rc)
854 goto out;
855 }
856 }
857
858 avc_latest_notif_update(seqno, 0);
859out:
860 return rc;
861}
862
863/**
864 * avc_has_perm_noaudit - Check permissions but perform no auditing.
865 * @ssid: source security identifier
866 * @tsid: target security identifier
867 * @tclass: target security class
868 * @requested: requested permissions, interpreted based on @tclass
869 * @avd: access vector decisions
870 *
871 * Check the AVC to determine whether the @requested permissions are granted
872 * for the SID pair (@ssid, @tsid), interpreting the permissions
873 * based on @tclass, and call the security server on a cache miss to obtain
874 * a new decision and add it to the cache. Return a copy of the decisions
875 * in @avd. Return %0 if all @requested permissions are granted,
876 * -%EACCES if any permissions are denied, or another -errno upon
877 * other errors. This function is typically called by avc_has_perm(),
878 * but may also be called directly to separate permission checking from
879 * auditing, e.g. in cases where a lock must be held for the check but
880 * should be released for the auditing.
881 */
882int avc_has_perm_noaudit(u32 ssid, u32 tsid,
883 u16 tclass, u32 requested,
884 struct av_decision *avd)
885{
886 struct avc_node *node;
887 struct avc_entry entry, *p_ae;
888 int rc = 0;
889 u32 denied;
890
891 rcu_read_lock();
892
893 node = avc_lookup(ssid, tsid, tclass, requested);
894 if (!node) {
895 rcu_read_unlock();
896 rc = security_compute_av(ssid,tsid,tclass,requested,&entry.avd);
897 if (rc)
898 goto out;
899 rcu_read_lock();
900 node = avc_insert(ssid,tsid,tclass,&entry);
901 }
902
903 p_ae = node ? &node->ae : &entry;
904
905 if (avd)
906 memcpy(avd, &p_ae->avd, sizeof(*avd));
907
908 denied = requested & ~(p_ae->avd.allowed);
909
910 if (!requested || denied) {
911 if (selinux_enforcing)
912 rc = -EACCES;
913 else
914 if (node)
915 avc_update_node(AVC_CALLBACK_GRANT,requested,
916 ssid,tsid,tclass);
917 }
918
919 rcu_read_unlock();
920out:
921 return rc;
922}
923
924/**
925 * avc_has_perm - Check permissions and perform any appropriate auditing.
926 * @ssid: source security identifier
927 * @tsid: target security identifier
928 * @tclass: target security class
929 * @requested: requested permissions, interpreted based on @tclass
930 * @auditdata: auxiliary audit data
931 *
932 * Check the AVC to determine whether the @requested permissions are granted
933 * for the SID pair (@ssid, @tsid), interpreting the permissions
934 * based on @tclass, and call the security server on a cache miss to obtain
935 * a new decision and add it to the cache. Audit the granting or denial of
936 * permissions in accordance with the policy. Return %0 if all @requested
937 * permissions are granted, -%EACCES if any permissions are denied, or
938 * another -errno upon other errors.
939 */
940int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
941 u32 requested, struct avc_audit_data *auditdata)
942{
943 struct av_decision avd;
944 int rc;
945
946 rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, &avd);
947 avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
948 return rc;
949}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-29 13:35:08 -0500