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) {   .tclass = c,\
  57                         .common_pts = common_##i##_perm_to_string,\
  58                         .common_base =  b },
  59 #include "av_inherit.h"
  60 #undef S_
  61 };
  62
  63 const struct selinux_class_perm selinux_class_perm = {
  64         .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)
  70 };
  71
  72 #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
  77 #define avc_cache_stats_incr(field)                             \
  78 do {                                                            \
  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
  86 struct avc_entry {
  87         u32                     ssid;
  88         u32                     tsid;
  89         u16                     tclass;
  90         struct av_decision      avd;
  91         atomic_t                used;   /* used recently */
  92 };
  93
  94 struct avc_node {
  95         struct avc_entry        ae;
  96         struct list_head        list;
  97         struct rcu_head         rhead;
  98 };
  99
 100 struct avc_cache {
 101         struct list_head        slots[AVC_CACHE_SLOTS];
 102         spinlock_t              slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */
 103         atomic_t                lru_hint;       /* LRU hint for reclaim scan */
 104         atomic_t                active_nodes;
 105         u32                     latest_notif;   /* latest revocation notification */
 106 };
 107
 108 struct avc_callback_node {
 109         int (*callback) (u32 event, u32 ssid, u32 tsid,
 110                          u16 tclass, u32 perms,
 111                          u32 *out_retained);
 112         u32 events;
 113         u32 ssid;
 114         u32 tsid;
 115         u16 tclass;
 116         u32 perms;
 117         struct avc_callback_node *next;
 118 };
 119
 120 /* Exported via selinufs */
 121 unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
 122
 123 #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
 124 DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 };
 125 #endif
 126
 127 static struct avc_cache avc_cache;
 128 static struct avc_callback_node *avc_callbacks;
 129 static struct kmem_cache *avc_node_cachep;
 130
 131 static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
 132 {
 133         return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1);
 134 }
 135
 136 /**
 137  * avc_dump_av - Display an access vector in human-readable form.
 138  * @tclass: target security class
 139  * @av: access vector
 140  */
 141 void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
 142 {
 143         const char **common_pts = NULL;
 144         u32 common_base = 0;
 145         int i, i2, perm;
 146
 147         if (av == 0) {
 148                 audit_log_format(ab, " null");
 149                 return;
 150         }
 151
 152         for (i = 0; i < ARRAY_SIZE(av_inherit); i++) {
 153                 if (av_inherit[i].tclass == tclass) {
 154                         common_pts = av_inherit[i].common_pts;
 155                         common_base = av_inherit[i].common_base;
 156                         break;
 157                 }
 158         }
 159
 160         audit_log_format(ab, " {");
 161         i = 0;
 162         perm = 1;
 163         while (perm < common_base) {
 164                 if (perm & av) {
 165                         audit_log_format(ab, " %s", common_pts[i]);
 166                         av &= ~perm;
 167                 }
 168                 i++;
 169                 perm <<= 1;
 170         }
 171
 172         while (i < sizeof(av) * 8) {
 173                 if (perm & av) {
 174                         for (i2 = 0; i2 < ARRAY_SIZE(av_perm_to_string); i2++) {
 175                                 if ((av_perm_to_string[i2].tclass == tclass) &&
 176                                     (av_perm_to_string[i2].value == perm))
 177                                         break;
 178                         }
 179                         if (i2 < ARRAY_SIZE(av_perm_to_string)) {
 180                                 audit_log_format(ab, " %s",
 181                                                  av_perm_to_string[i2].name);
 182                                 av &= ~perm;
 183                         }
 184                 }
 185                 i++;
 186                 perm <<= 1;
 187         }
 188
 189         if (av)
 190                 audit_log_format(ab, " 0x%x", av);
 191
 192         audit_log_format(ab, " }");
 193 }
 194
 195 /**
 196  * avc_dump_query - Display a SID pair and a class in human-readable form.
 197  * @ssid: source security identifier
 198  * @tsid: target security identifier
 199  * @tclass: target security class
 200  */
 201 static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass)
 202 {
 203         int rc;
 204         char *scontext;
 205         u32 scontext_len;
 206
 207         rc = security_sid_to_context(ssid, &scontext, &scontext_len);
 208         if (rc)
 209                 audit_log_format(ab, "ssid=%d", ssid);
 210         else {
 211                 audit_log_format(ab, "scontext=%s", scontext);
 212                 kfree(scontext);
 213         }
 214
 215         rc = security_sid_to_context(tsid, &scontext, &scontext_len);
 216         if (rc)
 217                 audit_log_format(ab, " tsid=%d", tsid);
 218         else {
 219                 audit_log_format(ab, " tcontext=%s", scontext);
 220                 kfree(scontext);
 221         }
 222
 223         BUG_ON(tclass >= ARRAY_SIZE(class_to_string) || !class_to_string[tclass]);
 224         audit_log_format(ab, " tclass=%s", class_to_string[tclass]);
 225 }
 226
 227 /**
 228  * avc_init - Initialize the AVC.
 229  *
 230  * Initialize the access vector cache.
 231  */
 232 void __init avc_init(void)
 233 {
 234         int i;
 235
 236         for (i = 0; i < AVC_CACHE_SLOTS; i++) {
 237                 INIT_LIST_HEAD(&avc_cache.slots[i]);
 238                 spin_lock_init(&avc_cache.slots_lock[i]);
 239         }
 240         atomic_set(&avc_cache.active_nodes, 0);
 241         atomic_set(&avc_cache.lru_hint, 0);
 242
 243         avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node),
 244                                              0, SLAB_PANIC, NULL);
 245
 246         audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED\n");
 247 }
 248
 249 int avc_get_hash_stats(char *page)
 250 {
 251         int i, chain_len, max_chain_len, slots_used;
 252         struct avc_node *node;
 253
 254         rcu_read_lock();
 255
 256         slots_used = 0;
 257         max_chain_len = 0;
 258         for (i = 0; i < AVC_CACHE_SLOTS; i++) {
 259                 if (!list_empty(&avc_cache.slots[i])) {
 260                         slots_used++;
 261                         chain_len = 0;
 262                         list_for_each_entry_rcu(node, &avc_cache.slots[i], list)
 263                                 chain_len++;
 264                         if (chain_len > max_chain_len)
 265                                 max_chain_len = chain_len;
 266                 }
 267         }
 268
 269         rcu_read_unlock();
 270
 271         return scnprintf(page, PAGE_SIZE, "entries: %d\nbuckets used: %d/%d\n"
 272                          "longest chain: %d\n",
 273                          atomic_read(&avc_cache.active_nodes),
 274                          slots_used, AVC_CACHE_SLOTS, max_chain_len);
 275 }
 276
 277 static void avc_node_free(struct rcu_head *rhead)
 278 {
 279         struct avc_node *node = container_of(rhead, struct avc_node, rhead);
 280         kmem_cache_free(avc_node_cachep, node);
 281         avc_cache_stats_incr(frees);
 282 }
 283
 284 static void avc_node_delete(struct avc_node *node)
 285 {
 286         list_del_rcu(&node->list);
 287         call_rcu(&node->rhead, avc_node_free);
 288         atomic_dec(&avc_cache.active_nodes);
 289 }
 290
 291 static void avc_node_kill(struct avc_node *node)
 292 {
 293         kmem_cache_free(avc_node_cachep, node);
 294         avc_cache_stats_incr(frees);
 295         atomic_dec(&avc_cache.active_nodes);
 296 }
 297
 298 static void avc_node_replace(struct avc_node *new, struct avc_node *old)
 299 {
 300         list_replace_rcu(&old->list, &new->list);
 301         call_rcu(&old->rhead, avc_node_free);
 302         atomic_dec(&avc_cache.active_nodes);
 303 }
 304
 305 static inline int avc_reclaim_node(void)
 306 {
 307         struct avc_node *node;
 308         int hvalue, try, ecx;
 309         unsigned long flags;
 310
 311         for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) {
 312                 hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);
 313
 314                 if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))
 315                         continue;
 316
 317                 rcu_read_lock();
 318                 list_for_each_entry(node, &avc_cache.slots[hvalue], list) {
 319                         if (atomic_dec_and_test(&node->ae.used)) {
 320                                 /* Recently Unused */
 321                                 avc_node_delete(node);
 322                                 avc_cache_stats_incr(reclaims);
 323                                 ecx++;
 324                                 if (ecx >= AVC_CACHE_RECLAIM) {
 325                                         rcu_read_unlock();
 326                                         spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
 327                                         goto out;
 328                                 }
 329                         }
 330                 }
 331                 rcu_read_unlock();
 332                 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);
 333         }
 334 out:
 335         return ecx;
 336 }
 337
 338 static struct avc_node *avc_alloc_node(void)
 339 {
 340         struct avc_node *node;
 341
 342         node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC);
 343         if (!node)
 344                 goto out;
 345
 346         INIT_RCU_HEAD(&node->rhead);
 347         INIT_LIST_HEAD(&node->list);
 348         atomic_set(&node->ae.used, 1);
 349         avc_cache_stats_incr(allocations);
 350
 351         if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
 352                 avc_reclaim_node();
 353
 354 out:
 355         return node;
 356 }
 357
 358 static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
 359 {
 360         node->ae.ssid = ssid;
 361         node->ae.tsid = tsid;
 362         node->ae.tclass = tclass;
 363         memcpy(&node->ae.avd, &ae->avd, sizeof(node->ae.avd));
 364 }
 365
 366 static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
 367 {
 368         struct avc_node *node, *ret = NULL;
 369         int hvalue;
 370
 371         hvalue = avc_hash(ssid, tsid, tclass);
 372         list_for_each_entry_rcu(node, &avc_cache.slots[hvalue], list) {
 373                 if (ssid == node->ae.ssid &&
 374                     tclass == node->ae.tclass &&
 375                     tsid == node->ae.tsid) {
 376                         ret = node;
 377                         break;
 378                 }
 379         }
 380
 381         if (ret == NULL) {
 382                 /* cache miss */
 383                 goto out;
 384         }
 385
 386         /* cache hit */
 387         if (atomic_read(&ret->ae.used) != 1)
 388                 atomic_set(&ret->ae.used, 1);
 389 out:
 390         return ret;
 391 }
 392
 393 /**
 394  * avc_lookup - Look up an AVC entry.
 395  * @ssid: source security identifier
 396  * @tsid: target security identifier
 397  * @tclass: target security class
 398  * @requested: requested permissions, interpreted based on @tclass
 399  *
 400  * Look up an AVC entry that is valid for the
 401  * @requested permissions between the SID pair
 402  * (@ssid, @tsid), interpreting the permissions
 403  * based on @tclass.  If a valid AVC entry exists,
 404  * then this function return the avc_node.
 405  * Otherwise, this function returns NULL.
 406  */
 407 static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass, u32 requested)
 408 {
 409         struct avc_node *node;
 410
 411         avc_cache_stats_incr(lookups);
 412         node = avc_search_node(ssid, tsid, tclass);
 413
 414         if (node && ((node->ae.avd.decided & requested) == requested)) {
 415                 avc_cache_stats_incr(hits);
 416                 goto out;
 417         }
 418
 419         node = NULL;
 420         avc_cache_stats_incr(misses);
 421 out:
 422         return node;
 423 }
 424
 425 static int avc_latest_notif_update(int seqno, int is_insert)
 426 {
 427         int ret = 0;
 428         static DEFINE_SPINLOCK(notif_lock);
 429         unsigned long flag;
 430
 431         spin_lock_irqsave(&notif_lock, flag);
 432         if (is_insert) {
 433                 if (seqno < avc_cache.latest_notif) {
 434                         printk(KERN_WARNING "SELinux: avc:  seqno %d < latest_notif %d\n",
 435                                seqno, avc_cache.latest_notif);
 436                         ret = -EAGAIN;
 437                 }
 438         } else {
 439                 if (seqno > avc_cache.latest_notif)
 440                         avc_cache.latest_notif = seqno;
 441         }
 442         spin_unlock_irqrestore(&notif_lock, flag);
 443
 444         return ret;
 445 }
 446
 447 /**
 448  * avc_insert - Insert an AVC entry.
 449  * @ssid: source security identifier
 450  * @tsid: target security identifier
 451  * @tclass: target security class
 452  * @ae: AVC entry
 453  *
 454  * Insert an AVC entry for the SID pair
 455  * (@ssid, @tsid) and class @tclass.
 456  * The access vectors and the sequence number are
 457  * normally provided by the security server in
 458  * response to a security_compute_av() call.  If the
 459  * sequence number @ae->avd.seqno is not less than the latest
 460  * revocation notification, then the function copies
 461  * the access vectors into a cache entry, returns
 462  * avc_node inserted. Otherwise, this function returns NULL.
 463  */
 464 static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct avc_entry *ae)
 465 {
 466         struct avc_node *pos, *node = NULL;
 467         int hvalue;
 468         unsigned long flag;
 469
 470         if (avc_latest_notif_update(ae->avd.seqno, 1))
 471                 goto out;
 472
 473         node = avc_alloc_node();
 474         if (node) {
 475                 hvalue = avc_hash(ssid, tsid, tclass);
 476                 avc_node_populate(node, ssid, tsid, tclass, ae);
 477
 478                 spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
 479                 list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
 480                         if (pos->ae.ssid == ssid &&
 481                             pos->ae.tsid == tsid &&
 482                             pos->ae.tclass == tclass) {
 483                                 avc_node_replace(node, pos);
 484                                 goto found;
 485                         }
 486                 }
 487                 list_add_rcu(&node->list, &avc_cache.slots[hvalue]);
 488 found:
 489                 spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
 490         }
 491 out:
 492         return node;
 493 }
 494
 495 static inline void avc_print_ipv6_addr(struct audit_buffer *ab,
 496                                        struct in6_addr *addr, __be16 port,
 497                                        char *name1, char *name2)
 498 {
 499         if (!ipv6_addr_any(addr))
 500                 audit_log_format(ab, " %s=%pI6", name1, addr);
 501         if (port)
 502                 audit_log_format(ab, " %s=%d", name2, ntohs(port));
 503 }
 504
 505 static inline void avc_print_ipv4_addr(struct audit_buffer *ab, __be32 addr,
 506                                        __be16 port, char *name1, char *name2)
 507 {
 508         if (addr)
 509                 audit_log_format(ab, " %s=%pI4", name1, &addr);
 510         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  */
 533 void avc_audit(u32 ssid, u32 tsid,
 534                u16 tclass, u32 requested,
 535                struct av_decision *avd, int result, struct avc_audit_data *a)
 536 {
 537         struct task_struct *tsk = current;
 538         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;
 549         } else {
 550                 audited = requested;
 551                 if (!(audited & avd->auditallow))
 552                         return;
 553         }
 554
 555         ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
 556         if (!ab)
 557                 return;         /* audit_panic has been called */
 558         audit_log_format(ab, "avc:  %s ", denied ? "denied" : "granted");
 559         avc_dump_av(ab, tclass, audited);
 560         audit_log_format(ab, " for ");
 561         if (a && a->tsk)
 562                 tsk = a->tsk;
 563         if (tsk && tsk->pid) {
 564                 audit_log_format(ab, " pid=%d comm=", tsk->pid);
 565                 audit_log_untrustedstring(ab, tsk->comm);
 566         }
 567         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:
 576                         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);
 581                                 } else {
 582                                         audit_log_format(ab, " name=");
 583                                         audit_log_untrustedstring(ab, dentry->d_name.name);
 584                                 }
 585                                 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) {
 591                                         audit_log_format(ab, " name=");
 592                                         audit_log_untrustedstring(ab, dentry->d_name.name);
 593                                         dput(dentry);
 594                                 }
 595                         }
 596                         if (inode)
 597                                 audit_log_format(ab, " dev=%s ino=%lu",
 598                                                  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) {
 635                                                 struct path path = {
 636                                                         .dentry = u->dentry,
 637                                                         .mnt = u->mnt
 638                                                 };
 639                                                 audit_log_d_path(ab, "path=",
 640                                                                  &path);
 641                                                 break;
 642                                         }
 643                                         if (!u->addr)
 644                                                 break;
 645                                         len = u->addr->len-sizeof(short);
 646                                         p = &u->addr->name->sun_path[0];
 647                                         audit_log_format(ab, " path=");
 648                                         if (*p)
 649                                                 audit_log_untrustedstring(ab, p);
 650                                         else
 651                                                 audit_log_n_hex(ab, p, len);
 652                                         break;
 653                                 }
 654                         }
 655
 656                         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                         }
 674                         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                         }
 686                         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  */
 709 int avc_add_callback(int (*callback)(u32 event, u32 ssid, u32 tsid,
 710                                      u16 tclass, u32 perms,
 711                                      u32 *out_retained),
 712                      u32 events, u32 ssid, u32 tsid,
 713                      u16 tclass, u32 perms)
 714 {
 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;
 731 out:
 732         return rc;
 733 }
 734
 735 static 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
 745  *
 746  * if a valid AVC entry doesn't exist,this function returns -ENOENT.
 747  * if kmalloc() called internal returns NULL, this function returns -ENOMEM.
 748  * otherwise, this function update the AVC entry. The original AVC-entry object
 749  * will release later by RCU.
 750  */
 751 static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass)
 752 {
 753         int hvalue, rc = 0;
 754         unsigned long flag;
 755         struct avc_node *pos, *node, *orig = NULL;
 756
 757         node = avc_alloc_node();
 758         if (!node) {
 759                 rc = -ENOMEM;
 760                 goto out;
 761         }
 762
 763         /* Lock the target slot */
 764         hvalue = avc_hash(ssid, tsid, tclass);
 765         spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);
 766
 767         list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {
 768                 if (ssid == pos->ae.ssid &&
 769                     tsid == pos->ae.tsid &&
 770                     tclass == pos->ae.tclass){
 771                         orig = pos;
 772                         break;
 773                 }
 774         }
 775
 776         if (!orig) {
 777                 rc = -ENOENT;
 778                 avc_node_kill(node);
 779                 goto out_unlock;
 780         }
 781
 782         /*
 783          * Copy and replace original node.
 784          */
 785
 786         avc_node_populate(node, ssid, tsid, tclass, &orig->ae);
 787
 788         switch (event) {
 789         case AVC_CALLBACK_GRANT:
 790                 node->ae.avd.allowed |= perms;
 791                 break;
 792         case AVC_CALLBACK_TRY_REVOKE:
 793         case AVC_CALLBACK_REVOKE:
 794                 node->ae.avd.allowed &= ~perms;
 795                 break;
 796         case AVC_CALLBACK_AUDITALLOW_ENABLE:
 797                 node->ae.avd.auditallow |= perms;
 798                 break;
 799         case AVC_CALLBACK_AUDITALLOW_DISABLE:
 800                 node->ae.avd.auditallow &= ~perms;
 801                 break;
 802         case AVC_CALLBACK_AUDITDENY_ENABLE:
 803                 node->ae.avd.auditdeny |= perms;
 804                 break;
 805         case AVC_CALLBACK_AUDITDENY_DISABLE:
 806                 node->ae.avd.auditdeny &= ~perms;
 807                 break;
 808         }
 809         avc_node_replace(node, orig);
 810 out_unlock:
 811         spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);
 812 out:
 813         return rc;
 814 }
 815
 816 /**
 817  * avc_ss_reset - Flush the cache and revalidate migrated permissions.
 818  * @seqno: policy sequence number
 819  */
 820 int avc_ss_reset(u32 seqno)
 821 {
 822         struct avc_callback_node *c;
 823         int i, rc = 0, tmprc;
 824         unsigned long flag;
 825         struct avc_node *node;
 826
 827         for (i = 0; i < AVC_CACHE_SLOTS; i++) {
 828                 spin_lock_irqsave(&avc_cache.slots_lock[i], flag);
 829                 /*
 830                  * With preemptable RCU, the outer spinlock does not
 831                  * prevent RCU grace periods from ending.
 832                  */
 833                 rcu_read_lock();
 834                 list_for_each_entry(node, &avc_cache.slots[i], list)
 835                         avc_node_delete(node);
 836                 rcu_read_unlock();
 837                 spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);
 838         }
 839
 840         for (c = avc_callbacks; c; c = c->next) {
 841                 if (c->events & AVC_CALLBACK_RESET) {
 842                         tmprc = c->callback(AVC_CALLBACK_RESET,
 843                                             0, 0, 0, 0, NULL);
 844                         /* save the first error encountered for the return
 845                            value and continue processing the callbacks */
 846                         if (!rc)
 847                                 rc = tmprc;
 848                 }
 849         }
 850
 851         avc_latest_notif_update(seqno, 0);
 852         return rc;
 853 }
 854
 855 /**
 856  * avc_has_perm_noaudit - Check permissions but perform no auditing.
 857  * @ssid: source security identifier
 858  * @tsid: target security identifier
 859  * @tclass: target security class
 860  * @requested: requested permissions, interpreted based on @tclass
 861  * @flags:  AVC_STRICT or 0
 862  * @avd: access vector decisions
 863  *
 864  * Check the AVC to determine whether the @requested permissions are granted
 865  * for the SID pair (@ssid, @tsid), interpreting the permissions
 866  * based on @tclass, and call the security server on a cache miss to obtain
 867  * a new decision and add it to the cache.  Return a copy of the decisions
 868  * in @avd.  Return %0 if all @requested permissions are granted,
 869  * -%EACCES if any permissions are denied, or another -errno upon
 870  * other errors.  This function is typically called by avc_has_perm(),
 871  * but may also be called directly to separate permission checking from
 872  * auditing, e.g. in cases where a lock must be held for the check but
 873  * should be released for the auditing.
 874  */
 875 int avc_has_perm_noaudit(u32 ssid, u32 tsid,
 876                          u16 tclass, u32 requested,
 877                          unsigned flags,
 878                          struct av_decision *avd)
 879 {
 880         struct avc_node *node;
 881         struct avc_entry entry, *p_ae;
 882         int rc = 0;
 883         u32 denied;
 884
 885         BUG_ON(!requested);
 886
 887         rcu_read_lock();
 888
 889         node = avc_lookup(ssid, tsid, tclass, requested);
 890         if (!node) {
 891                 rcu_read_unlock();
 892                 rc = security_compute_av(ssid, tsid, tclass, requested, &entry.avd);
 893                 if (rc)
 894                         goto out;
 895                 rcu_read_lock();
 896                 node = avc_insert(ssid, tsid, tclass, &entry);
 897         }
 898
 899         p_ae = node ? &node->ae : &entry;
 900
 901         if (avd)
 902                 memcpy(avd, &p_ae->avd, sizeof(*avd));
 903
 904         denied = requested & ~(p_ae->avd.allowed);
 905
 906         if (denied) {
 907                 if (flags & AVC_STRICT)
 908                         rc = -EACCES;
 909                 else if (!selinux_enforcing || security_permissive_sid(ssid))
 910                         avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,
 911                                         tsid, tclass);
 912                 else
 913                         rc = -EACCES;
 914         }
 915
 916         rcu_read_unlock();
 917 out:
 918         return rc;
 919 }
 920
 921 /**
 922  * avc_has_perm - Check permissions and perform any appropriate auditing.
 923  * @ssid: source security identifier
 924  * @tsid: target security identifier
 925  * @tclass: target security class
 926  * @requested: requested permissions, interpreted based on @tclass
 927  * @auditdata: auxiliary audit data
 928  *
 929  * Check the AVC to determine whether the @requested permissions are granted
 930  * for the SID pair (@ssid, @tsid), interpreting the permissions
 931  * based on @tclass, and call the security server on a cache miss to obtain
 932  * a new decision and add it to the cache.  Audit the granting or denial of
 933  * permissions in accordance with the policy.  Return %0 if all @requested
 934  * permissions are granted, -%EACCES if any permissions are denied, or
 935  * another -errno upon other errors.
 936  */
 937 int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
 938                  u32 requested, struct avc_audit_data *auditdata)
 939 {
 940         struct av_decision avd;
 941         int rc;
 942
 943         rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd);
 944         avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
 945         return rc;
 946 }
 947
 948 u32 avc_policy_seqno(void)
 949 {
 950         return avc_cache.latest_notif;
 951 }