security/selinux/avc.c

   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
  35 static const struct av_perm_to_string av_perm_to_string[] = {
  36 #define S_(c, v, s) { c, v, s },
  37 #include "av_perm_to_string.h"
  38 #undef S_
  39 };
  40
  41 static const char *class_to_string[] = {
  42 #define S_(s) s,
  43 #include "class_to_string.h"
  44 #undef S_
  45 };
  46
  47 #define TB_(s) static const char * s [] = {
  48 #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
  55 static const struct av_inherit av_inherit[] = {
  56 #define S_(c, i, b) { c, common_##i##_perm_to_string, b },
  57 #include "av_inherit.h"
  58 #undef S_
  59 };
  60
  61 const 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
  70 #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
  75 #define avc_cache_stats_incr(field)                             \
  76 do {                                                            \
  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
  84 struct avc_entry {
  85         u32                     ssid;
  86         u32                     tsid;
  87         u16                     tclass;
  88         struct av_decision      avd;
  89         atomic_t                used;   /* used recently */
  90 };
  91
  92 struct avc_node {
  93         struct avc_entry        ae;
  94         struct list_head        list;
  95         struct rcu_head         rhead;
  96 };
  97
  98 struct 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
 106 struct avc_callback_node {
 107         int (*callback) (u32 event, u32 ssid, u32 tsid,
 108                          u16 tclass, u32 perms,
 109                          u32 *out_retained);
 110         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 */
 119 unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
 120
 121 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
 122 DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 };
 123 #endif
 124
 125 static struct avc_cache avc_cache;
 126 static struct avc_callback_node *avc_callbacks;
 127 static struct kmem_cache *avc_node_cachep;
 128
 129 static 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  */
 139 static 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  */
 199 static 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
 205         rc = security_sid_to_context(ssid, &scontext, &scontext_len);
 206         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         }
 220
 221         BUG_ON(tclass >= ARRAY_SIZE(class_to_string) || !class_to_string[tclass]);
 222         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  */
 230 void __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),
 242                                              0, SLAB_PANIC, NULL);
 243
 244         audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n");
 245 }
 246
 247 int 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
 275 static 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
 282 static 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
 289 static 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
 296 static 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
 303 static inline int avc_reclaim_node(void)
 304 {
 305         struct avc_node *node;
 306         int hvalue, try, ecx;
 307         unsigned long flags;
 308
 309         for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++ ) {
 310                 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
 315                 list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
 316                         if (atomic_dec_and_test(&node->ae.used)) {
 317                                 /* Recently Unused */
 318                                 avc_node_delete(node);
 319                                 avc_cache_stats_incr(reclaims);
 320                                 ecx++;
 321                                 if (ecx >= AVC_CACHE_RECLAIM) {
 322                                         spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
 323                                         goto out;
 324                                 }
 325                         }
 326                 }
 327                 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
 328         }
 329 out:
 330         return ecx;
 331 }
 332
 333 static struct avc_node *avc_alloc_node(void)
 334 {
 335         struct avc_node *node;
 336
 337         node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC);
 338         if (!node)
 339                 goto out;
 340
 341         INIT_RCU_HEAD(&node->rhead);
 342         INIT_LIST_HEAD(&node->list);
 343         atomic_set(&node->ae.used, 1);
 344         avc_cache_stats_incr(allocations);
 345
 346         if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
 347                 avc_reclaim_node();
 348
 349 out:
 350         return node;
 351 }
 352
 353 static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
 354 {
 355         node->ae.ssid = ssid;
 356         node->ae.tsid = tsid;
 357         node->ae.tclass = tclass;
 358         memcpy(&node->ae.avd, &ae->avd, sizeof(node->ae.avd));
 359 }
 360
 361 static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
 362 {
 363         struct avc_node *node, *ret = NULL;
 364         int hvalue;
 365
 366         hvalue = avc_hash(ssid, tsid, tclass);
 367         list_for_each_entry_rcu(node, &avc_cache.slots[hvalue], list) {
 368                 if (ssid == node->ae.ssid &&
 369                     tclass == node->ae.tclass &&
 370                     tsid == node->ae.tsid) {
 371                         ret = node;
 372                         break;
 373                 }
 374         }
 375
 376         if (ret == NULL) {
 377                 /* cache miss */
 378                 goto out;
 379         }
 380
 381         /* cache hit */
 382         if (atomic_read(&ret->ae.used) != 1)
 383                 atomic_set(&ret->ae.used, 1);
 384 out:
 385         return ret;
 386 }
 387
 388 /**
 389  * avc_lookup - Look up an AVC entry.
 390  * @ssid: source security identifier
 391  * @tsid: target security identifier
 392  * @tclass: target security class
 393  * @requested: requested permissions, interpreted based on @tclass
 394  *
 395  * Look up an AVC entry that is valid for the
 396  * @requested permissions between the SID pair
 397  * (@ssid, @tsid), interpreting the permissions
 398  * based on @tclass.  If a valid AVC entry exists,
 399  * then this function return the avc_node.
 400  * Otherwise, this function returns NULL.
 401  */
 402 static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass, u32 requested)
 403 {
 404         struct avc_node *node;
 405
 406         avc_cache_stats_incr(lookups);
 407         node = avc_search_node(ssid, tsid, tclass);
 408
 409         if (node && ((node->ae.avd.decided & requested) == requested)) {
 410                 avc_cache_stats_incr(hits);
 411                 goto out;
 412         }
 413
 414         node = NULL;
 415         avc_cache_stats_incr(misses);
 416 out:
 417         return node;
 418 }
 419
 420 static int avc_latest_notif_update(int seqno, int is_insert)
 421 {
 422         int ret = 0;
 423         static DEFINE_SPINLOCK(notif_lock);
 424         unsigned long flag;
 425
 426         spin_lock_irqsave(&notif_lock, flag);
 427         if (is_insert) {
 428                 if (seqno < avc_cache.latest_notif) {
 429                         printk(KERN_WARNING "avc:  seqno %d < latest_notif %d\n",
 430                                seqno, avc_cache.latest_notif);
 431                         ret = -EAGAIN;
 432                 }
 433         } else {
 434                 if (seqno > avc_cache.latest_notif)
 435                         avc_cache.latest_notif = seqno;
 436         }
 437         spin_unlock_irqrestore(&notif_lock, flag);
 438
 439         return ret;
 440 }
 441
 442 /**
 443  * avc_insert - Insert an AVC entry.
 444  * @ssid: source security identifier
 445  * @tsid: target security identifier
 446  * @tclass: target security class
 447  * @ae: AVC entry
 448  *
 449  * Insert an AVC entry for the SID pair
 450  * (@ssid, @tsid) and class @tclass.
 451  * The access vectors and the sequence number are
 452  * normally provided by the security server in
 453  * response to a security_compute_av() call.  If the
 454  * sequence number @ae->avd.seqno is not less than the latest
 455  * revocation notification, then the function copies
 456  * the access vectors into a cache entry, returns
 457  * avc_node inserted. Otherwise, this function returns NULL.
 458  */
 459 static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
 460 {
 461         struct avc_node *pos, *node = NULL;
 462         int hvalue;
 463         unsigned long flag;
 464
 465         if (avc_latest_notif_update(ae->avd.seqno, 1))
 466                 goto out;
 467
 468         node = avc_alloc_node();
 469         if (node) {
 470                 hvalue = avc_hash(ssid, tsid, tclass);
 471                 avc_node_populate(node, ssid, tsid, tclass, ae);
 472
 473                 spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
 474                 list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
 475                         if (pos->ae.ssid == ssid &&
 476                             pos->ae.tsid == tsid &&
 477                             pos->ae.tclass == tclass) {
 478                                 avc_node_replace(node, pos);
 479                                 goto found;
 480                         }
 481                 }
 482                 list_add_rcu(&node->list, &avc_cache.slots[hvalue]);
 483 found:
 484                 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
 485         }
 486 out:
 487         return node;
 488 }
 489
 490 static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
 491                                        struct in6_addr *addr, __be16 port,
 492                                        char *name1, char *name2)
 493 {
 494         if (!ipv6_addr_any(addr))
 495                 audit_log_format(ab, " %s=" NIP6_FMT, name1, NIP6(*addr));
 496         if (port)
 497                 audit_log_format(ab, " %s=%d", name2, ntohs(port));
 498 }
 499
 500 static inline void avc_print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
 501                                        __be16 port, char *name1, char *name2)
 502 {
 503         if (addr)
 504                 audit_log_format(ab, " %s=" NIPQUAD_FMT, name1, NIPQUAD(addr));
 505         if (port)
 506                 audit_log_format(ab, " %s=%d", name2, ntohs(port));
 507 }
 508
 509 /**
 510  * avc_audit - Audit the granting or denial of permissions.
 511  * @ssid: source security identifier
 512  * @tsid: target security identifier
 513  * @tclass: target security class
 514  * @requested: requested permissions
 515  * @avd: access vector decisions
 516  * @result: result from avc_has_perm_noaudit
 517  * @a:  auxiliary audit data
 518  *
 519  * Audit the granting or denial of permissions in accordance
 520  * with the policy.  This function is typically called by
 521  * avc_has_perm() after a permission check, but can also be
 522  * called directly by callers who use avc_has_perm_noaudit()
 523  * in order to separate the permission check from the auditing.
 524  * For example, this separation is useful when the permission check must
 525  * be performed under a lock, to allow the lock to be released
 526  * before calling the auditing code.
 527  */
 528 void avc_audit(u32 ssid, u32 tsid,
 529                u16 tclass, u32 requested,
 530                struct av_decision *avd, int result, struct avc_audit_data *a)
 531 {
 532         struct task_struct *tsk = current;
 533         struct inode *inode = NULL;
 534         u32 denied, audited;
 535         struct audit_buffer *ab;
 536
 537         denied = requested & ~avd->allowed;
 538         if (denied) {
 539                 audited = denied;
 540                 if (!(audited & avd->auditdeny))
 541                         return;
 542         } else if (result) {
 543                 audited = denied = requested;
 544         } else {
 545                 audited = requested;
 546                 if (!(audited & avd->auditallow))
 547                         return;
 548         }
 549
 550         ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
 551         if (!ab)
 552                 return;         /* audit_panic has been called */
 553         audit_log_format(ab, "avc:  %s ", denied ? "denied" : "granted");
 554         avc_dump_av(ab, tclass,audited);
 555         audit_log_format(ab, " for ");
 556         if (a && a->tsk)
 557                 tsk = a->tsk;
 558         if (tsk && tsk->pid) {
 559                 audit_log_format(ab, " pid=%d comm=", tsk->pid);
 560                 audit_log_untrustedstring(ab, tsk->comm);
 561         }
 562         if (a) {
 563                 switch (a->type) {
 564                 case AVC_AUDIT_DATA_IPC:
 565                         audit_log_format(ab, " key=%d", a->u.ipc_id);
 566                         break;
 567                 case AVC_AUDIT_DATA_CAP:
 568                         audit_log_format(ab, " capability=%d", a->u.cap);
 569                         break;
 570                 case AVC_AUDIT_DATA_FS:
 571                         if (a->u.fs.path.dentry) {
 572                                 struct dentry *dentry = a->u.fs.path.dentry;
 573                                 if (a->u.fs.path.mnt) {
 574                                         audit_log_d_path(ab, "path=",
 575                                                          &a->u.fs.path);
 576                                 } else {
 577                                         audit_log_format(ab, " name=");
 578                                         audit_log_untrustedstring(ab, dentry->d_name.name);
 579                                 }
 580                                 inode = dentry->d_inode;
 581                         } else if (a->u.fs.inode) {
 582                                 struct dentry *dentry;
 583                                 inode = a->u.fs.inode;
 584                                 dentry = d_find_alias(inode);
 585                                 if (dentry) {
 586                                         audit_log_format(ab, " name=");
 587                                         audit_log_untrustedstring(ab, dentry->d_name.name);
 588                                         dput(dentry);
 589                                 }
 590                         }
 591                         if (inode)
 592                                 audit_log_format(ab, " dev=%s ino=%lu",
 593                                                  inode->i_sb->s_id,
 594                                                  inode->i_ino);
 595                         break;
 596                 case AVC_AUDIT_DATA_NET:
 597                         if (a->u.net.sk) {
 598                                 struct sock *sk = a->u.net.sk;
 599                                 struct unix_sock *u;
 600                                 int len = 0;
 601                                 char *p = NULL;
 602
 603                                 switch (sk->sk_family) {
 604                                 case AF_INET: {
 605                                         struct inet_sock *inet = inet_sk(sk);
 606
 607                                         avc_print_ipv4_addr(ab, inet->rcv_saddr,
 608                                                             inet->sport,
 609                                                             "laddr", "lport");
 610                                         avc_print_ipv4_addr(ab, inet->daddr,
 611                                                             inet->dport,
 612                                                             "faddr", "fport");
 613                                         break;
 614                                 }
 615                                 case AF_INET6: {
 616                                         struct inet_sock *inet = inet_sk(sk);
 617                                         struct ipv6_pinfo *inet6 = inet6_sk(sk);
 618
 619                                         avc_print_ipv6_addr(ab, &inet6->rcv_saddr,
 620                                                             inet->sport,
 621                                                             "laddr", "lport");
 622                                         avc_print_ipv6_addr(ab, &inet6->daddr,
 623                                                             inet->dport,
 624                                                             "faddr", "fport");
 625                                         break;
 626                                 }
 627                                 case AF_UNIX:
 628                                         u = unix_sk(sk);
 629                                         if (u->dentry) {
 630                                                 struct path path = {
 631                                                         .dentry = u->dentry,
 632                                                         .mnt = u->mnt
 633                                                 };
 634                                                 audit_log_d_path(ab, "path=",
 635                                                                  &path);
 636                                                 break;
 637                                         }
 638                                         if (!u->addr)
 639                                                 break;
 640                                         len = u->addr->len-sizeof(short);
 641                                         p = &u->addr->name->sun_path[0];
 642                                         audit_log_format(ab, " path=");
 643                                         if (*p)
 644                                                 audit_log_untrustedstring(ab, p);
 645                                         else
 646                                                 audit_log_hex(ab, p, len);
 647                                         break;
 648                                 }
 649                         }
 650
 651                         switch (a->u.net.family) {
 652                         case AF_INET:
 653                                 avc_print_ipv4_addr(ab, a->u.net.v4info.saddr,
 654                                                     a->u.net.sport,
 655                                                     "saddr", "src");
 656                                 avc_print_ipv4_addr(ab, a->u.net.v4info.daddr,
 657                                                     a->u.net.dport,
 658                                                     "daddr", "dest");
 659                                 break;
 660                         case AF_INET6:
 661                                 avc_print_ipv6_addr(ab, &a->u.net.v6info.saddr,
 662                                                     a->u.net.sport,
 663                                                     "saddr", "src");
 664                                 avc_print_ipv6_addr(ab, &a->u.net.v6info.daddr,
 665                                                     a->u.net.dport,
 666                                                     "daddr", "dest");
 667                                 break;
 668                         }
 669                         if (a->u.net.netif > 0) {
 670                                 struct net_device *dev;
 671
 672                                 /* NOTE: we always use init's namespace */
 673                                 dev = dev_get_by_index(&init_net,
 674                                                        a->u.net.netif);
 675                                 if (dev) {
 676                                         audit_log_format(ab, " netif=%s",
 677                                                          dev->name);
 678                                         dev_put(dev);
 679                                 }
 680                         }
 681                         break;
 682                 }
 683         }
 684         audit_log_format(ab, " ");
 685         avc_dump_query(ab, ssid, tsid, tclass);
 686         audit_log_end(ab);
 687 }
 688
 689 /**
 690  * avc_add_callback - Register a callback for security events.
 691  * @callback: callback function
 692  * @events: security events
 693  * @ssid: source security identifier or %SECSID_WILD
 694  * @tsid: target security identifier or %SECSID_WILD
 695  * @tclass: target security class
 696  * @perms: permissions
 697  *
 698  * Register a callback function for events in the set @events
 699  * related to the SID pair (@ssid, @tsid) and
 700  * and the permissions @perms, interpreting
 701  * @perms based on @tclass.  Returns %0 on success or
 702  * -%ENOMEM if insufficient memory exists to add the callback.
 703  */
 704 int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
 705                                      u16 tclass, u32 perms,
 706                                      u32 *out_retained),
 707                      u32 events, u32 ssid, u32 tsid,
 708                      u16 tclass, u32 perms)
 709 {
 710         struct avc_callback_node *c;
 711         int rc = 0;
 712
 713         c = kmalloc(sizeof(*c), GFP_ATOMIC);
 714         if (!c) {
 715                 rc = -ENOMEM;
 716                 goto out;
 717         }
 718
 719         c->callback = callback;
 720         c->events = events;
 721         c->ssid = ssid;
 722         c->tsid = tsid;
 723         c->perms = perms;
 724         c->next = avc_callbacks;
 725         avc_callbacks = c;
 726 out:
 727         return rc;
 728 }
 729
 730 static inline int avc_sidcmp(u32 x, u32 y)
 731 {
 732         return (x == y || x == SECSID_WILD || y == SECSID_WILD);
 733 }
 734
 735 /**
 736  * avc_update_node Update an AVC entry
 737  * @event : Updating event
 738  * @perms : Permission mask bits
 739  * @ssid,@tsid,@tclass : identifier of an AVC entry
 740  *
 741  * if a valid AVC entry doesn't exist,this function returns -ENOENT.
 742  * if kmalloc() called internal returns NULL, this function returns -ENOMEM.
 743  * otherwise, this function update the AVC entry. The original AVC-entry object
 744  * will release later by RCU.
 745  */
 746 static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass)
 747 {
 748         int hvalue, rc = 0;
 749         unsigned long flag;
 750         struct avc_node *pos, *node, *orig = NULL;
 751
 752         node = avc_alloc_node();
 753         if (!node) {
 754                 rc = -ENOMEM;
 755                 goto out;
 756         }
 757
 758         /* Lock the target slot */
 759         hvalue = avc_hash(ssid, tsid, tclass);
 760         spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
 761
 762         list_for_each_entry(pos, &avc_cache.slots[hvalue], list){
 763                 if ( ssid==pos->ae.ssid &&
 764                      tsid==pos->ae.tsid &&
 765                      tclass==pos->ae.tclass ){
 766                         orig = pos;
 767                         break;
 768                 }
 769         }
 770
 771         if (!orig) {
 772                 rc = -ENOENT;
 773                 avc_node_kill(node);
 774                 goto out_unlock;
 775         }
 776
 777         /*
 778          * Copy and replace original node.
 779          */
 780
 781         avc_node_populate(node, ssid, tsid, tclass, &orig->ae);
 782
 783         switch (event) {
 784         case AVC_CALLBACK_GRANT:
 785                 node->ae.avd.allowed |= perms;
 786                 break;
 787         case AVC_CALLBACK_TRY_REVOKE:
 788         case AVC_CALLBACK_REVOKE:
 789                 node->ae.avd.allowed &= ~perms;
 790                 break;
 791         case AVC_CALLBACK_AUDITALLOW_ENABLE:
 792                 node->ae.avd.auditallow |= perms;
 793                 break;
 794         case AVC_CALLBACK_AUDITALLOW_DISABLE:
 795                 node->ae.avd.auditallow &= ~perms;
 796                 break;
 797         case AVC_CALLBACK_AUDITDENY_ENABLE:
 798                 node->ae.avd.auditdeny |= perms;
 799                 break;
 800         case AVC_CALLBACK_AUDITDENY_DISABLE:
 801                 node->ae.avd.auditdeny &= ~perms;
 802                 break;
 803         }
 804         avc_node_replace(node, orig);
 805 out_unlock:
 806         spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
 807 out:
 808         return rc;
 809 }
 810
 811 /**
 812  * avc_ss_reset - Flush the cache and revalidate migrated permissions.
 813  * @seqno: policy sequence number
 814  */
 815 int avc_ss_reset(u32 seqno)
 816 {
 817         struct avc_callback_node *c;
 818         int i, rc = 0, tmprc;
 819         unsigned long flag;
 820         struct avc_node *node;
 821
 822         for (i = 0; i < AVC_CACHE_SLOTS; i++) {
 823                 spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
 824                 list_for_each_entry(node, &avc_cache.slots[i], list)
 825                         avc_node_delete(node);
 826                 spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
 827         }
 828
 829         for (c = avc_callbacks; c; c = c->next) {
 830                 if (c->events & AVC_CALLBACK_RESET) {
 831                         tmprc = c->callback(AVC_CALLBACK_RESET,
 832                                             0, 0, 0, 0, NULL);
 833                         /* save the first error encountered for the return
 834                            value and continue processing the callbacks */
 835                         if (!rc)
 836                                 rc = tmprc;
 837                 }
 838         }
 839
 840         avc_latest_notif_update(seqno, 0);
 841         return rc;
 842 }
 843
 844 /**
 845  * avc_has_perm_noaudit - Check permissions but perform no auditing.
 846  * @ssid: source security identifier
 847  * @tsid: target security identifier
 848  * @tclass: target security class
 849  * @requested: requested permissions, interpreted based on @tclass
 850  * @flags:  AVC_STRICT or 0
 851  * @avd: access vector decisions
 852  *
 853  * Check the AVC to determine whether the @requested permissions are granted
 854  * for the SID pair (@ssid, @tsid), interpreting the permissions
 855  * based on @tclass, and call the security server on a cache miss to obtain
 856  * a new decision and add it to the cache.  Return a copy of the decisions
 857  * in @avd.  Return %0 if all @requested permissions are granted,
 858  * -%EACCES if any permissions are denied, or another -errno upon
 859  * other errors.  This function is typically called by avc_has_perm(),
 860  * but may also be called directly to separate permission checking from
 861  * auditing, e.g. in cases where a lock must be held for the check but
 862  * should be released for the auditing.
 863  */
 864 int avc_has_perm_noaudit(u32 ssid, u32 tsid,
 865                          u16 tclass, u32 requested,
 866                          unsigned flags,
 867                          struct av_decision *avd)
 868 {
 869         struct avc_node *node;
 870         struct avc_entry entry, *p_ae;
 871         int rc = 0;
 872         u32 denied;
 873
 874         rcu_read_lock();
 875
 876         node = avc_lookup(ssid, tsid, tclass, requested);
 877         if (!node) {
 878                 rcu_read_unlock();
 879                 rc = security_compute_av(ssid,tsid,tclass,requested,&entry.avd);
 880                 if (rc)
 881                         goto out;
 882                 rcu_read_lock();
 883                 node = avc_insert(ssid,tsid,tclass,&entry);
 884         }
 885
 886         p_ae = node ? &node->ae : &entry;
 887
 888         if (avd)
 889                 memcpy(avd, &p_ae->avd, sizeof(*avd));
 890
 891         denied = requested & ~(p_ae->avd.allowed);
 892
 893         if (!requested || denied) {
 894                 if (selinux_enforcing || (flags & AVC_STRICT))
 895                         rc = -EACCES;
 896                 else
 897                         if (node)
 898                                 avc_update_node(AVC_CALLBACK_GRANT,requested,
 899                                                 ssid,tsid,tclass);
 900         }
 901
 902         rcu_read_unlock();
 903 out:
 904         return rc;
 905 }
 906
 907 /**
 908  * avc_has_perm - Check permissions and perform any appropriate auditing.
 909  * @ssid: source security identifier
 910  * @tsid: target security identifier
 911  * @tclass: target security class
 912  * @requested: requested permissions, interpreted based on @tclass
 913  * @auditdata: auxiliary audit data
 914  *
 915  * Check the AVC to determine whether the @requested permissions are granted
 916  * for the SID pair (@ssid, @tsid), interpreting the permissions
 917  * based on @tclass, and call the security server on a cache miss to obtain
 918  * a new decision and add it to the cache.  Audit the granting or denial of
 919  * permissions in accordance with the policy.  Return %0 if all @requested
 920  * permissions are granted, -%EACCES if any permissions are denied, or
 921  * another -errno upon other errors.
 922  */
 923 int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
 924                  u32 requested, struct avc_audit_data *auditdata)
 925 {
 926         struct av_decision avd;
 927         int rc;
 928
 929         rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd);
 930         avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
 931         return rc;
 932 }
 933
 934 u32 avc_policy_seqno(void)
 935 {
 936         return avc_cache.latest_notif;
 937 }