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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[] = {
Eric Paris76f7ba32009-01-02 17:40:06 -050056#define S_(c, i, b) { .tclass = c,\
57 .common_pts = common_##i##_perm_to_string,\
58 .common_base = b },
Linus Torvalds1da177e2005-04-16 15:20:36 -070059#include "av_inherit.h"
60#undef S_
61};
62
Chad Sellers5c458992006-11-06 12:38:16 -050063const struct selinux_class_perm selinux_class_perm = {
Eric Paris76f7ba32009-01-02 17:40:06 -050064 .av_perm_to_string = av_perm_to_string,
65 .av_pts_len = ARRAY_SIZE(av_perm_to_string),
66 .class_to_string = class_to_string,
67 .cts_len = ARRAY_SIZE(class_to_string),
68 .av_inherit = av_inherit,
69 .av_inherit_len = ARRAY_SIZE(av_inherit)
Chad Sellers5c458992006-11-06 12:38:16 -050070};
71
Linus Torvalds1da177e2005-04-16 15:20:36 -070072#define AVC_CACHE_SLOTS 512
73#define AVC_DEF_CACHE_THRESHOLD 512
74#define AVC_CACHE_RECLAIM 16
75
76#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
Eric Paris95fff332008-04-17 14:42:10 -040077#define avc_cache_stats_incr(field) \
Linus Torvalds1da177e2005-04-16 15:20:36 -070078do { \
79 per_cpu(avc_cache_stats, get_cpu()).field++; \
80 put_cpu(); \
81} while (0)
82#else
83#define avc_cache_stats_incr(field) do {} while (0)
84#endif
85
86struct avc_entry {
87 u32 ssid;
88 u32 tsid;
89 u16 tclass;
90 struct av_decision avd;
Linus Torvalds1da177e2005-04-16 15:20:36 -070091};
92
93struct avc_node {
94 struct avc_entry ae;
Eric Paris26036652009-02-12 14:51:04 -050095 struct hlist_node list; /* anchored in avc_cache->slots[i] */
Eric Paris95fff332008-04-17 14:42:10 -040096 struct rcu_head rhead;
Linus Torvalds1da177e2005-04-16 15:20:36 -070097};
98
99struct avc_cache {
Eric Paris26036652009-02-12 14:51:04 -0500100 struct hlist_head slots[AVC_CACHE_SLOTS]; /* head for avc_node->list */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101 spinlock_t slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */
102 atomic_t lru_hint; /* LRU hint for reclaim scan */
103 atomic_t active_nodes;
104 u32 latest_notif; /* latest revocation notification */
105};
106
107struct avc_callback_node {
108 int (*callback) (u32 event, u32 ssid, u32 tsid,
Eric Paris95fff332008-04-17 14:42:10 -0400109 u16 tclass, u32 perms,
110 u32 *out_retained);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 u32 events;
112 u32 ssid;
113 u32 tsid;
114 u16 tclass;
115 u32 perms;
116 struct avc_callback_node *next;
117};
118
119/* Exported via selinufs */
120unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
121
122#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
123DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 };
124#endif
125
126static struct avc_cache avc_cache;
127static struct avc_callback_node *avc_callbacks;
Christoph Lametere18b8902006-12-06 20:33:20 -0800128static struct kmem_cache *avc_node_cachep;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129
130static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
131{
132 return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1);
133}
134
135/**
136 * avc_dump_av - Display an access vector in human-readable form.
137 * @tclass: target security class
138 * @av: access vector
139 */
KaiGai Koheid9250de2008-08-28 16:35:57 +0900140void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141{
142 const char **common_pts = NULL;
143 u32 common_base = 0;
144 int i, i2, perm;
145
146 if (av == 0) {
147 audit_log_format(ab, " null");
148 return;
149 }
150
151 for (i = 0; i < ARRAY_SIZE(av_inherit); i++) {
152 if (av_inherit[i].tclass == tclass) {
153 common_pts = av_inherit[i].common_pts;
154 common_base = av_inherit[i].common_base;
155 break;
156 }
157 }
158
159 audit_log_format(ab, " {");
160 i = 0;
161 perm = 1;
162 while (perm < common_base) {
163 if (perm & av) {
164 audit_log_format(ab, " %s", common_pts[i]);
165 av &= ~perm;
166 }
167 i++;
168 perm <<= 1;
169 }
170
171 while (i < sizeof(av) * 8) {
172 if (perm & av) {
173 for (i2 = 0; i2 < ARRAY_SIZE(av_perm_to_string); i2++) {
174 if ((av_perm_to_string[i2].tclass == tclass) &&
175 (av_perm_to_string[i2].value == perm))
176 break;
177 }
178 if (i2 < ARRAY_SIZE(av_perm_to_string)) {
179 audit_log_format(ab, " %s",
180 av_perm_to_string[i2].name);
181 av &= ~perm;
182 }
183 }
184 i++;
185 perm <<= 1;
186 }
187
188 if (av)
189 audit_log_format(ab, " 0x%x", av);
190
191 audit_log_format(ab, " }");
192}
193
194/**
195 * avc_dump_query - Display a SID pair and a class in human-readable form.
196 * @ssid: source security identifier
197 * @tsid: target security identifier
198 * @tclass: target security class
199 */
200static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass)
201{
202 int rc;
203 char *scontext;
204 u32 scontext_len;
205
Eric Paris95fff332008-04-17 14:42:10 -0400206 rc = security_sid_to_context(ssid, &scontext, &scontext_len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 if (rc)
208 audit_log_format(ab, "ssid=%d", ssid);
209 else {
210 audit_log_format(ab, "scontext=%s", scontext);
211 kfree(scontext);
212 }
213
214 rc = security_sid_to_context(tsid, &scontext, &scontext_len);
215 if (rc)
216 audit_log_format(ab, " tsid=%d", tsid);
217 else {
218 audit_log_format(ab, " tcontext=%s", scontext);
219 kfree(scontext);
220 }
Stephen Smalleya764ae42007-03-26 13:36:26 -0400221
222 BUG_ON(tclass >= ARRAY_SIZE(class_to_string) || !class_to_string[tclass]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 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++) {
Eric Paris26036652009-02-12 14:51:04 -0500236 INIT_HLIST_HEAD(&avc_cache.slots[i]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700237 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),
Paul Mundt20c2df82007-07-20 10:11:58 +0900243 0, SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244
David Woodhouse9ad9ad32005-06-22 15:04:33 +0100245 audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700246}
247
248int avc_get_hash_stats(char *page)
249{
250 int i, chain_len, max_chain_len, slots_used;
251 struct avc_node *node;
Eric Paris26036652009-02-12 14:51:04 -0500252 struct hlist_head *head;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700253
254 rcu_read_lock();
255
256 slots_used = 0;
257 max_chain_len = 0;
258 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
Eric Parisedf3d1a2009-02-12 14:50:59 -0500259 head = &avc_cache.slots[i];
Eric Paris26036652009-02-12 14:51:04 -0500260 if (!hlist_empty(head)) {
261 struct hlist_node *next;
262
Linus Torvalds1da177e2005-04-16 15:20:36 -0700263 slots_used++;
264 chain_len = 0;
Eric Paris26036652009-02-12 14:51:04 -0500265 hlist_for_each_entry_rcu(node, next, head, list)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266 chain_len++;
267 if (chain_len > max_chain_len)
268 max_chain_len = chain_len;
269 }
270 }
271
272 rcu_read_unlock();
273
274 return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
275 "longest chain: %d\n",
276 atomic_read(&avc_cache.active_nodes),
277 slots_used, AVC_CACHE_SLOTS, max_chain_len);
278}
279
280static void avc_node_free(struct rcu_head *rhead)
281{
282 struct avc_node *node = container_of(rhead, struct avc_node, rhead);
283 kmem_cache_free(avc_node_cachep, node);
284 avc_cache_stats_incr(frees);
285}
286
287static void avc_node_delete(struct avc_node *node)
288{
Eric Paris26036652009-02-12 14:51:04 -0500289 hlist_del_rcu(&node->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700290 call_rcu(&node->rhead, avc_node_free);
291 atomic_dec(&avc_cache.active_nodes);
292}
293
294static void avc_node_kill(struct avc_node *node)
295{
296 kmem_cache_free(avc_node_cachep, node);
297 avc_cache_stats_incr(frees);
298 atomic_dec(&avc_cache.active_nodes);
299}
300
301static void avc_node_replace(struct avc_node *new, struct avc_node *old)
302{
Eric Paris26036652009-02-12 14:51:04 -0500303 hlist_replace_rcu(&old->list, &new->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 call_rcu(&old->rhead, avc_node_free);
305 atomic_dec(&avc_cache.active_nodes);
306}
307
308static inline int avc_reclaim_node(void)
309{
310 struct avc_node *node;
311 int hvalue, try, ecx;
312 unsigned long flags;
Eric Paris26036652009-02-12 14:51:04 -0500313 struct hlist_head *head;
314 struct hlist_node *next;
Eric Parisedf3d1a2009-02-12 14:50:59 -0500315 spinlock_t *lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316
Eric Paris95fff332008-04-17 14:42:10 -0400317 for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);
Eric Parisedf3d1a2009-02-12 14:50:59 -0500319 head = &avc_cache.slots[hvalue];
320 lock = &avc_cache.slots_lock[hvalue];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Eric Parisedf3d1a2009-02-12 14:50:59 -0500322 if (!spin_trylock_irqsave(lock, flags))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 continue;
324
Paul E. McKenney61844252008-04-21 18:12:33 -0700325 rcu_read_lock();
Eric Paris26036652009-02-12 14:51:04 -0500326 hlist_for_each_entry(node, next, head, list) {
Eric Paris906d27d2009-02-12 14:50:43 -0500327 avc_node_delete(node);
328 avc_cache_stats_incr(reclaims);
329 ecx++;
330 if (ecx >= AVC_CACHE_RECLAIM) {
331 rcu_read_unlock();
Eric Parisedf3d1a2009-02-12 14:50:59 -0500332 spin_unlock_irqrestore(lock, flags);
Eric Paris906d27d2009-02-12 14:50:43 -0500333 goto out;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700334 }
335 }
Paul E. McKenney61844252008-04-21 18:12:33 -0700336 rcu_read_unlock();
Eric Parisedf3d1a2009-02-12 14:50:59 -0500337 spin_unlock_irqrestore(lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338 }
339out:
340 return ecx;
341}
342
343static struct avc_node *avc_alloc_node(void)
344{
345 struct avc_node *node;
346
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800347 node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700348 if (!node)
349 goto out;
350
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 INIT_RCU_HEAD(&node->rhead);
Eric Paris26036652009-02-12 14:51:04 -0500352 INIT_HLIST_NODE(&node->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353 avc_cache_stats_incr(allocations);
354
355 if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
356 avc_reclaim_node();
357
358out:
359 return node;
360}
361
Eric Paris21193dc2009-02-12 14:50:49 -0500362static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363{
364 node->ae.ssid = ssid;
365 node->ae.tsid = tsid;
366 node->ae.tclass = tclass;
Eric Paris21193dc2009-02-12 14:50:49 -0500367 memcpy(&node->ae.avd, avd, sizeof(node->ae.avd));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700368}
369
370static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
371{
372 struct avc_node *node, *ret = NULL;
373 int hvalue;
Eric Paris26036652009-02-12 14:51:04 -0500374 struct hlist_head *head;
375 struct hlist_node *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376
377 hvalue = avc_hash(ssid, tsid, tclass);
Eric Parisedf3d1a2009-02-12 14:50:59 -0500378 head = &avc_cache.slots[hvalue];
Eric Paris26036652009-02-12 14:51:04 -0500379 hlist_for_each_entry_rcu(node, next, head, list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700380 if (ssid == node->ae.ssid &&
381 tclass == node->ae.tclass &&
382 tsid == node->ae.tsid) {
383 ret = node;
384 break;
385 }
386 }
387
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 *
397 * Look up an AVC entry that is valid for the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700398 * (@ssid, @tsid), interpreting the permissions
399 * based on @tclass. If a valid AVC entry exists,
400 * then this function return the avc_node.
401 * Otherwise, this function returns NULL.
402 */
Eric Parisf1c63812009-02-12 14:50:54 -0500403static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700404{
405 struct avc_node *node;
406
407 avc_cache_stats_incr(lookups);
408 node = avc_search_node(ssid, tsid, tclass);
409
Eric Parisf1c63812009-02-12 14:50:54 -0500410 if (node)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411 avc_cache_stats_incr(hits);
Eric Parisf1c63812009-02-12 14:50:54 -0500412 else
413 avc_cache_stats_incr(misses);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 return node;
416}
417
418static int avc_latest_notif_update(int seqno, int is_insert)
419{
420 int ret = 0;
421 static DEFINE_SPINLOCK(notif_lock);
422 unsigned long flag;
423
424 spin_lock_irqsave(&notif_lock, flag);
425 if (is_insert) {
426 if (seqno < avc_cache.latest_notif) {
Eric Paris744ba352008-04-17 11:52:44 -0400427 printk(KERN_WARNING "SELinux: avc: seqno %d < latest_notif %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428 seqno, avc_cache.latest_notif);
429 ret = -EAGAIN;
430 }
431 } else {
432 if (seqno > avc_cache.latest_notif)
433 avc_cache.latest_notif = seqno;
434 }
435 spin_unlock_irqrestore(&notif_lock, flag);
436
437 return ret;
438}
439
440/**
441 * avc_insert - Insert an AVC entry.
442 * @ssid: source security identifier
443 * @tsid: target security identifier
444 * @tclass: target security class
Eric Paris21193dc2009-02-12 14:50:49 -0500445 * @avd: resulting av decision
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 *
447 * Insert an AVC entry for the SID pair
448 * (@ssid, @tsid) and class @tclass.
449 * The access vectors and the sequence number are
450 * normally provided by the security server in
451 * response to a security_compute_av() call. If the
Eric Paris21193dc2009-02-12 14:50:49 -0500452 * sequence number @avd->seqno is not less than the latest
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 * revocation notification, then the function copies
454 * the access vectors into a cache entry, returns
455 * avc_node inserted. Otherwise, this function returns NULL.
456 */
Eric Paris21193dc2009-02-12 14:50:49 -0500457static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458{
459 struct avc_node *pos, *node = NULL;
460 int hvalue;
461 unsigned long flag;
462
Eric Paris21193dc2009-02-12 14:50:49 -0500463 if (avc_latest_notif_update(avd->seqno, 1))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 goto out;
465
466 node = avc_alloc_node();
467 if (node) {
Eric Paris26036652009-02-12 14:51:04 -0500468 struct hlist_head *head;
469 struct hlist_node *next;
Eric Parisedf3d1a2009-02-12 14:50:59 -0500470 spinlock_t *lock;
471
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 hvalue = avc_hash(ssid, tsid, tclass);
Eric Paris21193dc2009-02-12 14:50:49 -0500473 avc_node_populate(node, ssid, tsid, tclass, avd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474
Eric Parisedf3d1a2009-02-12 14:50:59 -0500475 head = &avc_cache.slots[hvalue];
476 lock = &avc_cache.slots_lock[hvalue];
477
478 spin_lock_irqsave(lock, flag);
Eric Paris26036652009-02-12 14:51:04 -0500479 hlist_for_each_entry(pos, next, head, list) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 if (pos->ae.ssid == ssid &&
481 pos->ae.tsid == tsid &&
482 pos->ae.tclass == tclass) {
Eric Paris95fff332008-04-17 14:42:10 -0400483 avc_node_replace(node, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 goto found;
485 }
486 }
Eric Paris26036652009-02-12 14:51:04 -0500487 hlist_add_head_rcu(&node->list, head);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488found:
Eric Parisedf3d1a2009-02-12 14:50:59 -0500489 spin_unlock_irqrestore(lock, flag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490 }
491out:
492 return node;
493}
494
495static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
Alexey Dobriyanb5bf6c52005-09-03 15:55:17 -0700496 struct in6_addr *addr, __be16 port,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 char *name1, char *name2)
498{
499 if (!ipv6_addr_any(addr))
Harvey Harrison5b095d9892008-10-29 12:52:50 -0700500 audit_log_format(ab, " %s=%pI6", name1, addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 if (port)
502 audit_log_format(ab, " %s=%d", name2, ntohs(port));
503}
504
Al Viro87fcd702006-12-04 22:00:55 +0000505static inline void avc_print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
Alexey Dobriyanb5bf6c52005-09-03 15:55:17 -0700506 __be16 port, char *name1, char *name2)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507{
508 if (addr)
Harvey Harrison3685f25d2008-10-31 00:56:49 -0700509 audit_log_format(ab, " %s=%pI4", name1, &addr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700510 if (port)
511 audit_log_format(ab, " %s=%d", name2, ntohs(port));
512}
513
514/**
515 * avc_audit - Audit the granting or denial of permissions.
516 * @ssid: source security identifier
517 * @tsid: target security identifier
518 * @tclass: target security class
519 * @requested: requested permissions
520 * @avd: access vector decisions
521 * @result: result from avc_has_perm_noaudit
522 * @a: auxiliary audit data
523 *
524 * Audit the granting or denial of permissions in accordance
525 * with the policy. This function is typically called by
526 * avc_has_perm() after a permission check, but can also be
527 * called directly by callers who use avc_has_perm_noaudit()
528 * in order to separate the permission check from the auditing.
529 * For example, this separation is useful when the permission check must
530 * be performed under a lock, to allow the lock to be released
531 * before calling the auditing code.
532 */
533void avc_audit(u32 ssid, u32 tsid,
Eric Paris95fff332008-04-17 14:42:10 -0400534 u16 tclass, u32 requested,
535 struct av_decision *avd, int result, struct avc_audit_data *a)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536{
David Woodhousecd77b822005-05-19 11:18:24 +0100537 struct task_struct *tsk = current;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 struct inode *inode = NULL;
539 u32 denied, audited;
540 struct audit_buffer *ab;
541
542 denied = requested & ~avd->allowed;
543 if (denied) {
544 audited = denied;
545 if (!(audited & avd->auditdeny))
546 return;
547 } else if (result) {
548 audited = denied = requested;
Eric Paris95fff332008-04-17 14:42:10 -0400549 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 audited = requested;
551 if (!(audited & avd->auditallow))
552 return;
553 }
554
David Woodhouse9ad9ad32005-06-22 15:04:33 +0100555 ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 if (!ab)
557 return; /* audit_panic has been called */
558 audit_log_format(ab, "avc: %s ", denied ? "denied" : "granted");
Eric Paris95fff332008-04-17 14:42:10 -0400559 avc_dump_av(ab, tclass, audited);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 audit_log_format(ab, " for ");
David Woodhousecd77b822005-05-19 11:18:24 +0100561 if (a && a->tsk)
562 tsk = a->tsk;
David Woodhouse7b5d7812005-05-21 16:52:57 +0100563 if (tsk && tsk->pid) {
David Woodhousecd77b822005-05-19 11:18:24 +0100564 audit_log_format(ab, " pid=%d comm=", tsk->pid);
565 audit_log_untrustedstring(ab, tsk->comm);
566 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 if (a) {
568 switch (a->type) {
569 case AVC_AUDIT_DATA_IPC:
570 audit_log_format(ab, " key=%d", a->u.ipc_id);
571 break;
572 case AVC_AUDIT_DATA_CAP:
573 audit_log_format(ab, " capability=%d", a->u.cap);
574 break;
575 case AVC_AUDIT_DATA_FS:
Jan Blunck44707fd2008-02-14 19:38:33 -0800576 if (a->u.fs.path.dentry) {
577 struct dentry *dentry = a->u.fs.path.dentry;
578 if (a->u.fs.path.mnt) {
579 audit_log_d_path(ab, "path=",
580 &a->u.fs.path);
Al Viro4259fa02007-06-07 11:13:31 -0400581 } else {
582 audit_log_format(ab, " name=");
583 audit_log_untrustedstring(ab, dentry->d_name.name);
584 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700585 inode = dentry->d_inode;
586 } else if (a->u.fs.inode) {
587 struct dentry *dentry;
588 inode = a->u.fs.inode;
589 dentry = d_find_alias(inode);
590 if (dentry) {
Stephen Smalley37ca5382005-05-24 21:28:28 +0100591 audit_log_format(ab, " name=");
592 audit_log_untrustedstring(ab, dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 dput(dentry);
594 }
595 }
596 if (inode)
Tobias Oed13bddc22007-06-11 08:56:31 -0400597 audit_log_format(ab, " dev=%s ino=%lu",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700598 inode->i_sb->s_id,
599 inode->i_ino);
600 break;
601 case AVC_AUDIT_DATA_NET:
602 if (a->u.net.sk) {
603 struct sock *sk = a->u.net.sk;
604 struct unix_sock *u;
605 int len = 0;
606 char *p = NULL;
607
608 switch (sk->sk_family) {
609 case AF_INET: {
610 struct inet_sock *inet = inet_sk(sk);
611
612 avc_print_ipv4_addr(ab, inet->rcv_saddr,
613 inet->sport,
614 "laddr", "lport");
615 avc_print_ipv4_addr(ab, inet->daddr,
616 inet->dport,
617 "faddr", "fport");
618 break;
619 }
620 case AF_INET6: {
621 struct inet_sock *inet = inet_sk(sk);
622 struct ipv6_pinfo *inet6 = inet6_sk(sk);
623
624 avc_print_ipv6_addr(ab, &inet6->rcv_saddr,
625 inet->sport,
626 "laddr", "lport");
627 avc_print_ipv6_addr(ab, &inet6->daddr,
628 inet->dport,
629 "faddr", "fport");
630 break;
631 }
632 case AF_UNIX:
633 u = unix_sk(sk);
634 if (u->dentry) {
Jan Blunck44707fd2008-02-14 19:38:33 -0800635 struct path path = {
636 .dentry = u->dentry,
637 .mnt = u->mnt
638 };
Al Viro4259fa02007-06-07 11:13:31 -0400639 audit_log_d_path(ab, "path=",
Jan Blunck44707fd2008-02-14 19:38:33 -0800640 &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 break;
642 }
643 if (!u->addr)
644 break;
645 len = u->addr->len-sizeof(short);
646 p = &u->addr->name->sun_path[0];
Stephen Smalley37ca5382005-05-24 21:28:28 +0100647 audit_log_format(ab, " path=");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700648 if (*p)
Stephen Smalley37ca5382005-05-24 21:28:28 +0100649 audit_log_untrustedstring(ab, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700650 else
Eric Parisb556f8a2008-04-18 10:12:59 -0400651 audit_log_n_hex(ab, p, len);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 break;
653 }
654 }
Eric Paris95fff332008-04-17 14:42:10 -0400655
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 switch (a->u.net.family) {
657 case AF_INET:
658 avc_print_ipv4_addr(ab, a->u.net.v4info.saddr,
659 a->u.net.sport,
660 "saddr", "src");
661 avc_print_ipv4_addr(ab, a->u.net.v4info.daddr,
662 a->u.net.dport,
663 "daddr", "dest");
664 break;
665 case AF_INET6:
666 avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr,
667 a->u.net.sport,
668 "saddr", "src");
669 avc_print_ipv6_addr(ab, &a->u.net.v6info.daddr,
670 a->u.net.dport,
671 "daddr", "dest");
672 break;
673 }
Paul Mooreda5645a2008-01-29 08:38:10 -0500674 if (a->u.net.netif > 0) {
675 struct net_device *dev;
676
677 /* NOTE: we always use init's namespace */
678 dev = dev_get_by_index(&init_net,
679 a->u.net.netif);
680 if (dev) {
681 audit_log_format(ab, " netif=%s",
682 dev->name);
683 dev_put(dev);
684 }
685 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 break;
687 }
688 }
689 audit_log_format(ab, " ");
690 avc_dump_query(ab, ssid, tsid, tclass);
691 audit_log_end(ab);
692}
693
694/**
695 * avc_add_callback - Register a callback for security events.
696 * @callback: callback function
697 * @events: security events
698 * @ssid: source security identifier or %SECSID_WILD
699 * @tsid: target security identifier or %SECSID_WILD
700 * @tclass: target security class
701 * @perms: permissions
702 *
703 * Register a callback function for events in the set @events
704 * related to the SID pair (@ssid, @tsid) and
705 * and the permissions @perms, interpreting
706 * @perms based on @tclass. Returns %0 on success or
707 * -%ENOMEM if insufficient memory exists to add the callback.
708 */
709int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
Eric Paris95fff332008-04-17 14:42:10 -0400710 u16 tclass, u32 perms,
711 u32 *out_retained),
712 u32 events, u32 ssid, u32 tsid,
713 u16 tclass, u32 perms)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714{
715 struct avc_callback_node *c;
716 int rc = 0;
717
718 c = kmalloc(sizeof(*c), GFP_ATOMIC);
719 if (!c) {
720 rc = -ENOMEM;
721 goto out;
722 }
723
724 c->callback = callback;
725 c->events = events;
726 c->ssid = ssid;
727 c->tsid = tsid;
728 c->perms = perms;
729 c->next = avc_callbacks;
730 avc_callbacks = c;
731out:
732 return rc;
733}
734
735static inline int avc_sidcmp(u32 x, u32 y)
736{
737 return (x == y || x == SECSID_WILD || y == SECSID_WILD);
738}
739
740/**
741 * avc_update_node Update an AVC entry
742 * @event : Updating event
743 * @perms : Permission mask bits
744 * @ssid,@tsid,@tclass : identifier of an AVC entry
Eric Parisa5dda6832009-02-12 14:50:11 -0500745 * @seqno : sequence number when decision was made
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 *
747 * if a valid AVC entry doesn't exist,this function returns -ENOENT.
748 * if kmalloc() called internal returns NULL, this function returns -ENOMEM.
749 * otherwise, this function update the AVC entry. The original AVC-entry object
750 * will release later by RCU.
751 */
Eric Parisa5dda6832009-02-12 14:50:11 -0500752static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass,
753 u32 seqno)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700754{
755 int hvalue, rc = 0;
756 unsigned long flag;
757 struct avc_node *pos, *node, *orig = NULL;
Eric Paris26036652009-02-12 14:51:04 -0500758 struct hlist_head *head;
759 struct hlist_node *next;
Eric Parisedf3d1a2009-02-12 14:50:59 -0500760 spinlock_t *lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761
762 node = avc_alloc_node();
763 if (!node) {
764 rc = -ENOMEM;
765 goto out;
766 }
767
768 /* Lock the target slot */
769 hvalue = avc_hash(ssid, tsid, tclass);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770
Eric Parisedf3d1a2009-02-12 14:50:59 -0500771 head = &avc_cache.slots[hvalue];
772 lock = &avc_cache.slots_lock[hvalue];
773
774 spin_lock_irqsave(lock, flag);
775
Eric Paris26036652009-02-12 14:51:04 -0500776 hlist_for_each_entry(pos, next, head, list) {
Eric Paris95fff332008-04-17 14:42:10 -0400777 if (ssid == pos->ae.ssid &&
778 tsid == pos->ae.tsid &&
Eric Parisa5dda6832009-02-12 14:50:11 -0500779 tclass == pos->ae.tclass &&
780 seqno == pos->ae.avd.seqno){
Linus Torvalds1da177e2005-04-16 15:20:36 -0700781 orig = pos;
782 break;
783 }
784 }
785
786 if (!orig) {
787 rc = -ENOENT;
788 avc_node_kill(node);
789 goto out_unlock;
790 }
791
792 /*
793 * Copy and replace original node.
794 */
795
Eric Paris21193dc2009-02-12 14:50:49 -0500796 avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700797
798 switch (event) {
799 case AVC_CALLBACK_GRANT:
800 node->ae.avd.allowed |= perms;
801 break;
802 case AVC_CALLBACK_TRY_REVOKE:
803 case AVC_CALLBACK_REVOKE:
804 node->ae.avd.allowed &= ~perms;
805 break;
806 case AVC_CALLBACK_AUDITALLOW_ENABLE:
807 node->ae.avd.auditallow |= perms;
808 break;
809 case AVC_CALLBACK_AUDITALLOW_DISABLE:
810 node->ae.avd.auditallow &= ~perms;
811 break;
812 case AVC_CALLBACK_AUDITDENY_ENABLE:
813 node->ae.avd.auditdeny |= perms;
814 break;
815 case AVC_CALLBACK_AUDITDENY_DISABLE:
816 node->ae.avd.auditdeny &= ~perms;
817 break;
818 }
819 avc_node_replace(node, orig);
820out_unlock:
Eric Parisedf3d1a2009-02-12 14:50:59 -0500821 spin_unlock_irqrestore(lock, flag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700822out:
823 return rc;
824}
825
826/**
827 * avc_ss_reset - Flush the cache and revalidate migrated permissions.
828 * @seqno: policy sequence number
829 */
830int avc_ss_reset(u32 seqno)
831{
832 struct avc_callback_node *c;
Darrel Goeddel376bd9c2006-02-24 15:44:05 -0600833 int i, rc = 0, tmprc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700834 unsigned long flag;
835 struct avc_node *node;
Eric Paris26036652009-02-12 14:51:04 -0500836 struct hlist_head *head;
837 struct hlist_node *next;
Eric Parisedf3d1a2009-02-12 14:50:59 -0500838 spinlock_t *lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700839
840 for (i = 0; i < AVC_CACHE_SLOTS; i++) {
Eric Parisedf3d1a2009-02-12 14:50:59 -0500841 head = &avc_cache.slots[i];
842 lock = &avc_cache.slots_lock[i];
843
844 spin_lock_irqsave(lock, flag);
Paul E. McKenney61844252008-04-21 18:12:33 -0700845 /*
846 * With preemptable RCU, the outer spinlock does not
847 * prevent RCU grace periods from ending.
848 */
849 rcu_read_lock();
Eric Paris26036652009-02-12 14:51:04 -0500850 hlist_for_each_entry(node, next, head, list)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700851 avc_node_delete(node);
Paul E. McKenney61844252008-04-21 18:12:33 -0700852 rcu_read_unlock();
Eric Parisedf3d1a2009-02-12 14:50:59 -0500853 spin_unlock_irqrestore(lock, flag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 }
855
856 for (c = avc_callbacks; c; c = c->next) {
857 if (c->events & AVC_CALLBACK_RESET) {
Darrel Goeddel376bd9c2006-02-24 15:44:05 -0600858 tmprc = c->callback(AVC_CALLBACK_RESET,
Eric Paris95fff332008-04-17 14:42:10 -0400859 0, 0, 0, 0, NULL);
Darrel Goeddel376bd9c2006-02-24 15:44:05 -0600860 /* save the first error encountered for the return
861 value and continue processing the callbacks */
862 if (!rc)
863 rc = tmprc;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700864 }
865 }
866
867 avc_latest_notif_update(seqno, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700868 return rc;
869}
870
871/**
872 * avc_has_perm_noaudit - Check permissions but perform no auditing.
873 * @ssid: source security identifier
874 * @tsid: target security identifier
875 * @tclass: target security class
876 * @requested: requested permissions, interpreted based on @tclass
Stephen Smalley2c3c05d2007-06-07 15:34:10 -0400877 * @flags: AVC_STRICT or 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700878 * @avd: access vector decisions
879 *
880 * Check the AVC to determine whether the @requested permissions are granted
881 * for the SID pair (@ssid, @tsid), interpreting the permissions
882 * based on @tclass, and call the security server on a cache miss to obtain
883 * a new decision and add it to the cache. Return a copy of the decisions
884 * in @avd. Return %0 if all @requested permissions are granted,
885 * -%EACCES if any permissions are denied, or another -errno upon
886 * other errors. This function is typically called by avc_has_perm(),
887 * but may also be called directly to separate permission checking from
888 * auditing, e.g. in cases where a lock must be held for the check but
889 * should be released for the auditing.
890 */
891int avc_has_perm_noaudit(u32 ssid, u32 tsid,
Stephen Smalley2c3c05d2007-06-07 15:34:10 -0400892 u16 tclass, u32 requested,
893 unsigned flags,
Eric Paris21193dc2009-02-12 14:50:49 -0500894 struct av_decision *in_avd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700895{
896 struct avc_node *node;
Eric Paris21193dc2009-02-12 14:50:49 -0500897 struct av_decision avd_entry, *avd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700898 int rc = 0;
899 u32 denied;
900
Eric Pariseda4f692008-03-11 14:19:34 -0400901 BUG_ON(!requested);
902
Linus Torvalds1da177e2005-04-16 15:20:36 -0700903 rcu_read_lock();
904
Eric Parisf1c63812009-02-12 14:50:54 -0500905 node = avc_lookup(ssid, tsid, tclass);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700906 if (!node) {
907 rcu_read_unlock();
Eric Paris21193dc2009-02-12 14:50:49 -0500908
909 if (in_avd)
910 avd = in_avd;
911 else
912 avd = &avd_entry;
913
914 rc = security_compute_av(ssid, tsid, tclass, requested, avd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700915 if (rc)
916 goto out;
917 rcu_read_lock();
Eric Paris21193dc2009-02-12 14:50:49 -0500918 node = avc_insert(ssid, tsid, tclass, avd);
919 } else {
920 if (in_avd)
921 memcpy(in_avd, &node->ae.avd, sizeof(*in_avd));
922 avd = &node->ae.avd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700923 }
924
Eric Paris21193dc2009-02-12 14:50:49 -0500925 denied = requested & ~(avd->allowed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700926
Eric Pariseda4f692008-03-11 14:19:34 -0400927 if (denied) {
Eric Paris64dbf072008-03-31 12:17:33 +1100928 if (flags & AVC_STRICT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700929 rc = -EACCES;
KaiGai Kohei8a6f83a2009-04-01 10:07:57 +0900930 else if (!selinux_enforcing || (avd->flags & AVD_FLAGS_PERMISSIVE))
Eric Paris64dbf072008-03-31 12:17:33 +1100931 avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,
Eric Paris21193dc2009-02-12 14:50:49 -0500932 tsid, tclass, avd->seqno);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 else
Eric Paris64dbf072008-03-31 12:17:33 +1100934 rc = -EACCES;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700935 }
936
937 rcu_read_unlock();
938out:
939 return rc;
940}
941
942/**
943 * avc_has_perm - Check permissions and perform any appropriate auditing.
944 * @ssid: source security identifier
945 * @tsid: target security identifier
946 * @tclass: target security class
947 * @requested: requested permissions, interpreted based on @tclass
948 * @auditdata: auxiliary audit data
949 *
950 * Check the AVC to determine whether the @requested permissions are granted
951 * for the SID pair (@ssid, @tsid), interpreting the permissions
952 * based on @tclass, and call the security server on a cache miss to obtain
953 * a new decision and add it to the cache. Audit the granting or denial of
954 * permissions in accordance with the policy. Return %0 if all @requested
955 * permissions are granted, -%EACCES if any permissions are denied, or
956 * another -errno upon other errors.
957 */
958int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
Eric Paris95fff332008-04-17 14:42:10 -0400959 u32 requested, struct avc_audit_data *auditdata)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960{
961 struct av_decision avd;
962 int rc;
963
Stephen Smalley2c3c05d2007-06-07 15:34:10 -0400964 rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
966 return rc;
967}
Yuichi Nakamura788e7dd2007-09-14 09:27:07 +0900968
969u32 avc_policy_seqno(void)
970{
971 return avc_cache.latest_notif;
972}