/*
   * Implementation of the kernel access vector cache (AVC).
   *
   * Authors:  Stephen Smalley, <sds@epoch.ncsc.mil>
   *	     James Morris <jmorris@redhat.com>
   *
   * Update:   KaiGai, Kohei <kaigai@ak.jp.nec.com>
   *	Replaced the avc_lock spinlock by RCU.
   *
   * Copyright (C) 2003 Red Hat, Inc., James Morris <jmorris@redhat.com>
   *
   *	This program is free software; you can redistribute it and/or modify
   *	it under the terms of the GNU General Public License version 2,
   *	as published by the Free Software Foundation.
   */
  #include <linux/types.h>
  #include <linux/stddef.h>
  #include <linux/kernel.h>
  #include <linux/slab.h>
  #include <linux/fs.h>
  #include <linux/dcache.h>
  #include <linux/init.h>
  #include <linux/skbuff.h>
  #include <linux/percpu.h>
  #include <net/sock.h>
  #include <linux/un.h>
  #include <net/af_unix.h>
  #include <linux/ip.h>
  #include <linux/audit.h>
  #include <linux/ipv6.h>
  #include <net/ipv6.h>
  #include "avc.h"
  #include "avc_ss.h"
  #include "classmap.h"
  
  #define AVC_CACHE_SLOTS			512
  #define AVC_DEF_CACHE_THRESHOLD		512
  #define AVC_CACHE_RECLAIM		16
  
  #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
  #define avc_cache_stats_incr(field)	this_cpu_inc(avc_cache_stats.field)
  #else
  #define avc_cache_stats_incr(field)	do {} while (0)
  #endif
  
  struct avc_entry {
  	u32			ssid;
  	u32			tsid;
  	u16			tclass;
  	struct av_decision	avd;
  };
  
  struct avc_node {
  	struct avc_entry	ae;
  	struct hlist_node	list; /* anchored in avc_cache->slots[i] */
  	struct rcu_head		rhead;
  };
  
  struct avc_cache {
  	struct hlist_head	slots[AVC_CACHE_SLOTS]; /* head for avc_node->list */
  	spinlock_t		slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */
  	atomic_t		lru_hint;	/* LRU hint for reclaim scan */
  	atomic_t		active_nodes;
  	u32			latest_notif;	/* latest revocation notification */
  };
  
  struct avc_callback_node {
  	int (*callback) (u32 event);
  	u32 events;
  	struct avc_callback_node *next;
  };
  
  /* Exported via selinufs */
  unsigned int avc_cache_threshold = AVC_DEF_CACHE_THRESHOLD;
  
  #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
  DEFINE_PER_CPU(struct avc_cache_stats, avc_cache_stats) = { 0 };
  #endif
  
  static struct avc_cache avc_cache;
  static struct avc_callback_node *avc_callbacks;
  static struct kmem_cache *avc_node_cachep;
  
  static inline int avc_hash(u32 ssid, u32 tsid, u16 tclass)
  {
  	return (ssid ^ (tsid<<2) ^ (tclass<<4)) & (AVC_CACHE_SLOTS - 1);
  }
  
  /**
   * avc_dump_av - Display an access vector in human-readable form.
   * @tclass: target security class
   * @av: access vector
   */
  static void avc_dump_av(struct audit_buffer *ab, u16 tclass, u32 av)
  {
  	const char **perms;
  	int i, perm;
  
  	if (av == 0) {
  		audit_log_format(ab, " null");
  		return;
  	}
  
  	perms = secclass_map[tclass-1].perms;
  
  	audit_log_format(ab, " {");
  	i = 0;
  	perm = 1;
  	while (i < (sizeof(av) * 8)) {
  		if ((perm & av) && perms[i]) {
  			audit_log_format(ab, " %s", perms[i]);
  			av &= ~perm;
  		}
  		i++;
  		perm <<= 1;
  	}
  
  	if (av)
  		audit_log_format(ab, " 0x%x", av);
  
  	audit_log_format(ab, " }");
  }
  
  /**
   * avc_dump_query - Display a SID pair and a class in human-readable form.
   * @ssid: source security identifier
   * @tsid: target security identifier
   * @tclass: target security class
   */
  static void avc_dump_query(struct audit_buffer *ab, u32 ssid, u32 tsid, u16 tclass)
  {
  	int rc;
  	char *scontext;
  	u32 scontext_len;
  
  	rc = security_sid_to_context(ssid, &scontext, &scontext_len);
  	if (rc)
  		audit_log_format(ab, "ssid=%d", ssid);
  	else {
  		audit_log_format(ab, "scontext=%s", scontext);
  		kfree(scontext);
  	}
  
  	rc = security_sid_to_context(tsid, &scontext, &scontext_len);
  	if (rc)
  		audit_log_format(ab, " tsid=%d", tsid);
  	else {
  		audit_log_format(ab, " tcontext=%s", scontext);
  		kfree(scontext);
  	}
  
  	BUG_ON(tclass >= ARRAY_SIZE(secclass_map));
  	audit_log_format(ab, " tclass=%s", secclass_map[tclass-1].name);
  }
  
  /**
   * avc_init - Initialize the AVC.
   *
   * Initialize the access vector cache.
   */
  void __init avc_init(void)
  {
  	int i;
  
  	for (i = 0; i < AVC_CACHE_SLOTS; i++) {
  		INIT_HLIST_HEAD(&avc_cache.slots[i]);
  		spin_lock_init(&avc_cache.slots_lock[i]);
  	}
  	atomic_set(&avc_cache.active_nodes, 0);
  	atomic_set(&avc_cache.lru_hint, 0);
  
  	avc_node_cachep = kmem_cache_create("avc_node", sizeof(struct avc_node),
  					     0, SLAB_PANIC, NULL);
  
  	audit_log(current->audit_context, GFP_KERNEL, AUDIT_KERNEL, "AVC INITIALIZED
  ");
  }
  
  int avc_get_hash_stats(char *page)
  {
  	int i, chain_len, max_chain_len, slots_used;
  	struct avc_node *node;
  	struct hlist_head *head;
  
  	rcu_read_lock();
  
  	slots_used = 0;
  	max_chain_len = 0;
  	for (i = 0; i < AVC_CACHE_SLOTS; i++) {
  		head = &avc_cache.slots[i];
  		if (!hlist_empty(head)) {
  			slots_used++;
  			chain_len = 0;
  			hlist_for_each_entry_rcu(node, head, list)
  				chain_len++;
  			if (chain_len > max_chain_len)
  				max_chain_len = chain_len;
  		}
  	}
  
  	rcu_read_unlock();
  
  	return scnprintf(page, PAGE_SIZE, "entries: %d
  buckets used: %d/%d
  "
  			 "longest chain: %d
  ",
  			 atomic_read(&avc_cache.active_nodes),
  			 slots_used, AVC_CACHE_SLOTS, max_chain_len);
  }
  
  static void avc_node_free(struct rcu_head *rhead)
  {
  	struct avc_node *node = container_of(rhead, struct avc_node, rhead);
  	kmem_cache_free(avc_node_cachep, node);
  	avc_cache_stats_incr(frees);
  }
  
  static void avc_node_delete(struct avc_node *node)
  {
  	hlist_del_rcu(&node->list);
  	call_rcu(&node->rhead, avc_node_free);
  	atomic_dec(&avc_cache.active_nodes);
  }
  
  static void avc_node_kill(struct avc_node *node)
  {
  	kmem_cache_free(avc_node_cachep, node);
  	avc_cache_stats_incr(frees);
  	atomic_dec(&avc_cache.active_nodes);
  }
  
  static void avc_node_replace(struct avc_node *new, struct avc_node *old)
  {
  	hlist_replace_rcu(&old->list, &new->list);
  	call_rcu(&old->rhead, avc_node_free);
  	atomic_dec(&avc_cache.active_nodes);
  }
  
  static inline int avc_reclaim_node(void)
  {
  	struct avc_node *node;
  	int hvalue, try, ecx;
  	unsigned long flags;
  	struct hlist_head *head;
  	spinlock_t *lock;
  
  	for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) {
  		hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);
  		head = &avc_cache.slots[hvalue];
  		lock = &avc_cache.slots_lock[hvalue];
  
  		if (!spin_trylock_irqsave(lock, flags))
  			continue;
  
  		rcu_read_lock();
  		hlist_for_each_entry(node, head, list) {
  			avc_node_delete(node);
  			avc_cache_stats_incr(reclaims);
  			ecx++;
  			if (ecx >= AVC_CACHE_RECLAIM) {
  				rcu_read_unlock();
  				spin_unlock_irqrestore(lock, flags);
  				goto out;
  			}
  		}
  		rcu_read_unlock();
  		spin_unlock_irqrestore(lock, flags);
  	}
  out:
  	return ecx;
  }
  
  static struct avc_node *avc_alloc_node(void)
  {
  	struct avc_node *node;
  
  	node = kmem_cache_zalloc(avc_node_cachep, GFP_ATOMIC|__GFP_NOMEMALLOC);
  	if (!node)
  		goto out;
  
  	INIT_HLIST_NODE(&node->list);
  	avc_cache_stats_incr(allocations);
  
  	if (atomic_inc_return(&avc_cache.active_nodes) > avc_cache_threshold)
  		avc_reclaim_node();
  
  out:
  	return node;
  }
  
  static void avc_node_populate(struct avc_node *node, u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd)
  {
  	node->ae.ssid = ssid;
  	node->ae.tsid = tsid;
  	node->ae.tclass = tclass;
  	memcpy(&node->ae.avd, avd, sizeof(node->ae.avd));
  }
  
  static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass)
  {
  	struct avc_node *node, *ret = NULL;
  	int hvalue;
  	struct hlist_head *head;
  
  	hvalue = avc_hash(ssid, tsid, tclass);
  	head = &avc_cache.slots[hvalue];
  	hlist_for_each_entry_rcu(node, head, list) {
  		if (ssid == node->ae.ssid &&
  		    tclass == node->ae.tclass &&
  		    tsid == node->ae.tsid) {
  			ret = node;
  			break;
  		}
  	}
  
  	return ret;
  }
  
  /**
   * avc_lookup - Look up an AVC entry.
   * @ssid: source security identifier
   * @tsid: target security identifier
   * @tclass: target security class
   *
   * Look up an AVC entry that is valid for the
   * (@ssid, @tsid), interpreting the permissions
   * based on @tclass.  If a valid AVC entry exists,
   * then this function returns the avc_node.
   * Otherwise, this function returns NULL.
   */
  static struct avc_node *avc_lookup(u32 ssid, u32 tsid, u16 tclass)
  {
  	struct avc_node *node;
  
  	avc_cache_stats_incr(lookups);
  	node = avc_search_node(ssid, tsid, tclass);
  
  	if (node)
  		return node;
  
  	avc_cache_stats_incr(misses);
  	return NULL;
  }
  
  static int avc_latest_notif_update(int seqno, int is_insert)
  {
  	int ret = 0;
  	static DEFINE_SPINLOCK(notif_lock);
  	unsigned long flag;
  
  	spin_lock_irqsave(&notif_lock, flag);
  	if (is_insert) {
  		if (seqno < avc_cache.latest_notif) {
  			printk(KERN_WARNING "SELinux: avc:  seqno %d < latest_notif %d
  ",
  			       seqno, avc_cache.latest_notif);
  			ret = -EAGAIN;
  		}
  	} else {
  		if (seqno > avc_cache.latest_notif)
  			avc_cache.latest_notif = seqno;
  	}
  	spin_unlock_irqrestore(&notif_lock, flag);
  
  	return ret;
  }
  
  /**
   * avc_insert - Insert an AVC entry.
   * @ssid: source security identifier
   * @tsid: target security identifier
   * @tclass: target security class
   * @avd: resulting av decision
   *
   * Insert an AVC entry for the SID pair
   * (@ssid, @tsid) and class @tclass.
   * The access vectors and the sequence number are
   * normally provided by the security server in
   * response to a security_compute_av() call.  If the
   * sequence number @avd->seqno is not less than the latest
   * revocation notification, then the function copies
   * the access vectors into a cache entry, returns
   * avc_node inserted. Otherwise, this function returns NULL.
   */
  static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_decision *avd)
  {
  	struct avc_node *pos, *node = NULL;
  	int hvalue;
  	unsigned long flag;
  
  	if (avc_latest_notif_update(avd->seqno, 1))
  		goto out;
  
  	node = avc_alloc_node();
  	if (node) {
  		struct hlist_head *head;
  		spinlock_t *lock;
  
  		hvalue = avc_hash(ssid, tsid, tclass);
  		avc_node_populate(node, ssid, tsid, tclass, avd);
  
  		head = &avc_cache.slots[hvalue];
  		lock = &avc_cache.slots_lock[hvalue];
  
  		spin_lock_irqsave(lock, flag);
  		hlist_for_each_entry(pos, head, list) {
  			if (pos->ae.ssid == ssid &&
  			    pos->ae.tsid == tsid &&
  			    pos->ae.tclass == tclass) {
  				avc_node_replace(node, pos);
  				goto found;
  			}
  		}
  		hlist_add_head_rcu(&node->list, head);
  found:
  		spin_unlock_irqrestore(lock, flag);
  	}
  out:
  	return node;
  }
  
  /**
   * avc_audit_pre_callback - SELinux specific information
   * will be called by generic audit code
   * @ab: the audit buffer
   * @a: audit_data
   */
  static void avc_audit_pre_callback(struct audit_buffer *ab, void *a)
  {
  	struct common_audit_data *ad = a;
  	audit_log_format(ab, "avc:  %s ",
  			 ad->selinux_audit_data->denied ? "denied" : "granted");
  	avc_dump_av(ab, ad->selinux_audit_data->tclass,
  			ad->selinux_audit_data->audited);
  	audit_log_format(ab, " for ");
  }
  
  /**
   * avc_audit_post_callback - SELinux specific information
   * will be called by generic audit code
   * @ab: the audit buffer
   * @a: audit_data
   */
  static void avc_audit_post_callback(struct audit_buffer *ab, void *a)
  {
  	struct common_audit_data *ad = a;
  	audit_log_format(ab, " ");
  	avc_dump_query(ab, ad->selinux_audit_data->ssid,
  			   ad->selinux_audit_data->tsid,
  			   ad->selinux_audit_data->tclass);
  }
  
  /* This is the slow part of avc audit with big stack footprint */
  noinline int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
  		u32 requested, u32 audited, u32 denied,
  		struct common_audit_data *a,
  		unsigned flags)
  {
  	struct common_audit_data stack_data;
  	struct selinux_audit_data sad;
  
  	if (!a) {
  		a = &stack_data;
  		a->type = LSM_AUDIT_DATA_NONE;
  	}
  
  	/*
  	 * When in a RCU walk do the audit on the RCU retry.  This is because
  	 * the collection of the dname in an inode audit message is not RCU
  	 * safe.  Note this may drop some audits when the situation changes
  	 * during retry. However this is logically just as if the operation
  	 * happened a little later.
  	 */
  	if ((a->type == LSM_AUDIT_DATA_INODE) &&
  	    (flags & MAY_NOT_BLOCK))
  		return -ECHILD;
  
  	sad.tclass = tclass;
  	sad.requested = requested;
  	sad.ssid = ssid;
  	sad.tsid = tsid;
  	sad.audited = audited;
  	sad.denied = denied;
  
  	a->selinux_audit_data = &sad;
  
  	common_lsm_audit(a, avc_audit_pre_callback, avc_audit_post_callback);
  	return 0;
  }
  
  /**
   * avc_add_callback - Register a callback for security events.
   * @callback: callback function
   * @events: security events
   *
   * Register a callback function for events in the set @events.
   * Returns %0 on success or -%ENOMEM if insufficient memory
   * exists to add the callback.
   */
  int __init avc_add_callback(int (*callback)(u32 event), u32 events)
  {
  	struct avc_callback_node *c;
  	int rc = 0;
  
  	c = kmalloc(sizeof(*c), GFP_KERNEL);
  	if (!c) {
  		rc = -ENOMEM;
  		goto out;
  	}
  
  	c->callback = callback;
  	c->events = events;
  	c->next = avc_callbacks;
  	avc_callbacks = c;
  out:
  	return rc;
  }
  
  static inline int avc_sidcmp(u32 x, u32 y)
  {
  	return (x == y || x == SECSID_WILD || y == SECSID_WILD);
  }
  
  /**
   * avc_update_node Update an AVC entry
   * @event : Updating event
   * @perms : Permission mask bits
   * @ssid,@tsid,@tclass : identifier of an AVC entry
   * @seqno : sequence number when decision was made
   *
   * if a valid AVC entry doesn't exist,this function returns -ENOENT.
   * if kmalloc() called internal returns NULL, this function returns -ENOMEM.
   * otherwise, this function updates the AVC entry. The original AVC-entry object
   * will release later by RCU.
   */
  static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass,
  			   u32 seqno)
  {
  	int hvalue, rc = 0;
  	unsigned long flag;
  	struct avc_node *pos, *node, *orig = NULL;
  	struct hlist_head *head;
  	spinlock_t *lock;
  
  	node = avc_alloc_node();
  	if (!node) {
  		rc = -ENOMEM;
  		goto out;
  	}
  
  	/* Lock the target slot */
  	hvalue = avc_hash(ssid, tsid, tclass);
  
  	head = &avc_cache.slots[hvalue];
  	lock = &avc_cache.slots_lock[hvalue];
  
  	spin_lock_irqsave(lock, flag);
  
  	hlist_for_each_entry(pos, head, list) {
  		if (ssid == pos->ae.ssid &&
  		    tsid == pos->ae.tsid &&
  		    tclass == pos->ae.tclass &&
  		    seqno == pos->ae.avd.seqno){
  			orig = pos;
  			break;
  		}
  	}
  
  	if (!orig) {
  		rc = -ENOENT;
  		avc_node_kill(node);
  		goto out_unlock;
  	}
  
  	/*
  	 * Copy and replace original node.
  	 */
  
  	avc_node_populate(node, ssid, tsid, tclass, &orig->ae.avd);
  
  	switch (event) {
  	case AVC_CALLBACK_GRANT:
  		node->ae.avd.allowed |= perms;
  		break;
  	case AVC_CALLBACK_TRY_REVOKE:
  	case AVC_CALLBACK_REVOKE:
  		node->ae.avd.allowed &= ~perms;
  		break;
  	case AVC_CALLBACK_AUDITALLOW_ENABLE:
  		node->ae.avd.auditallow |= perms;
  		break;
  	case AVC_CALLBACK_AUDITALLOW_DISABLE:
  		node->ae.avd.auditallow &= ~perms;
  		break;
  	case AVC_CALLBACK_AUDITDENY_ENABLE:
  		node->ae.avd.auditdeny |= perms;
  		break;
  	case AVC_CALLBACK_AUDITDENY_DISABLE:
  		node->ae.avd.auditdeny &= ~perms;
  		break;
  	}
  	avc_node_replace(node, orig);
  out_unlock:
  	spin_unlock_irqrestore(lock, flag);
  out:
  	return rc;
  }
  
  /**
   * avc_flush - Flush the cache
   */
  static void avc_flush(void)
  {
  	struct hlist_head *head;
  	struct avc_node *node;
  	spinlock_t *lock;
  	unsigned long flag;
  	int i;
  
  	for (i = 0; i < AVC_CACHE_SLOTS; i++) {
  		head = &avc_cache.slots[i];
  		lock = &avc_cache.slots_lock[i];
  
  		spin_lock_irqsave(lock, flag);
  		/*
  		 * With preemptable RCU, the outer spinlock does not
  		 * prevent RCU grace periods from ending.
  		 */
  		rcu_read_lock();
  		hlist_for_each_entry(node, head, list)
  			avc_node_delete(node);
  		rcu_read_unlock();
  		spin_unlock_irqrestore(lock, flag);
  	}
  }
  
  /**
   * avc_ss_reset - Flush the cache and revalidate migrated permissions.
   * @seqno: policy sequence number
   */
  int avc_ss_reset(u32 seqno)
  {
  	struct avc_callback_node *c;
  	int rc = 0, tmprc;
  
  	avc_flush();
  
  	for (c = avc_callbacks; c; c = c->next) {
  		if (c->events & AVC_CALLBACK_RESET) {
  			tmprc = c->callback(AVC_CALLBACK_RESET);
  			/* save the first error encountered for the return
  			   value and continue processing the callbacks */
  			if (!rc)
  				rc = tmprc;
  		}
  	}
  
  	avc_latest_notif_update(seqno, 0);
  	return rc;
  }
  
  /*
   * Slow-path helper function for avc_has_perm_noaudit,
   * when the avc_node lookup fails. We get called with
   * the RCU read lock held, and need to return with it
   * still held, but drop if for the security compute.
   *
   * Don't inline this, since it's the slow-path and just
   * results in a bigger stack frame.
   */
  static noinline struct avc_node *avc_compute_av(u32 ssid, u32 tsid,
  			 u16 tclass, struct av_decision *avd)
  {
  	rcu_read_unlock();
  	security_compute_av(ssid, tsid, tclass, avd);
  	rcu_read_lock();
  	return avc_insert(ssid, tsid, tclass, avd);
  }
  
  static noinline int avc_denied(u32 ssid, u32 tsid,
  			 u16 tclass, u32 requested,
  			 unsigned flags,
  			 struct av_decision *avd)
  {
  	if (flags & AVC_STRICT)
  		return -EACCES;
  
  	if (selinux_enforcing && !(avd->flags & AVD_FLAGS_PERMISSIVE))
  		return -EACCES;
  
  	avc_update_node(AVC_CALLBACK_GRANT, requested, ssid,
  				tsid, tclass, avd->seqno);
  	return 0;
  }
  
  
  /**
   * avc_has_perm_noaudit - Check permissions but perform no auditing.
   * @ssid: source security identifier
   * @tsid: target security identifier
   * @tclass: target security class
   * @requested: requested permissions, interpreted based on @tclass
   * @flags:  AVC_STRICT or 0
   * @avd: access vector decisions
   *
   * Check the AVC to determine whether the @requested permissions are granted
   * for the SID pair (@ssid, @tsid), interpreting the permissions
   * based on @tclass, and call the security server on a cache miss to obtain
   * a new decision and add it to the cache.  Return a copy of the decisions
   * in @avd.  Return %0 if all @requested permissions are granted,
   * -%EACCES if any permissions are denied, or another -errno upon
   * other errors.  This function is typically called by avc_has_perm(),
   * but may also be called directly to separate permission checking from
   * auditing, e.g. in cases where a lock must be held for the check but
   * should be released for the auditing.
   */
  inline int avc_has_perm_noaudit(u32 ssid, u32 tsid,
  			 u16 tclass, u32 requested,
  			 unsigned flags,
  			 struct av_decision *avd)
  {
  	struct avc_node *node;
  	int rc = 0;
  	u32 denied;
  
  	BUG_ON(!requested);
  
  	rcu_read_lock();
  
  	node = avc_lookup(ssid, tsid, tclass);
  	if (unlikely(!node)) {
  		node = avc_compute_av(ssid, tsid, tclass, avd);
  	} else {
  		memcpy(avd, &node->ae.avd, sizeof(*avd));
  		avd = &node->ae.avd;
  	}
  
  	denied = requested & ~(avd->allowed);
  	if (unlikely(denied))
  		rc = avc_denied(ssid, tsid, tclass, requested, flags, avd);
  
  	rcu_read_unlock();
  	return rc;
  }
  
  /**
   * avc_has_perm - Check permissions and perform any appropriate auditing.
   * @ssid: source security identifier
   * @tsid: target security identifier
   * @tclass: target security class
   * @requested: requested permissions, interpreted based on @tclass
   * @auditdata: auxiliary audit data
   *
   * Check the AVC to determine whether the @requested permissions are granted
   * for the SID pair (@ssid, @tsid), interpreting the permissions
   * based on @tclass, and call the security server on a cache miss to obtain
   * a new decision and add it to the cache.  Audit the granting or denial of
   * permissions in accordance with the policy.  Return %0 if all @requested
   * permissions are granted, -%EACCES if any permissions are denied, or
   * another -errno upon other errors.
   */
  int avc_has_perm(u32 ssid, u32 tsid, u16 tclass,
  		 u32 requested, struct common_audit_data *auditdata)
  {
  	struct av_decision avd;
  	int rc, rc2;
  
  	rc = avc_has_perm_noaudit(ssid, tsid, tclass, requested, 0, &avd);
  
  	rc2 = avc_audit(ssid, tsid, tclass, requested, &avd, rc, auditdata);
  	if (rc2)
  		return rc2;
  	return rc;
  }
  
  u32 avc_policy_seqno(void)
  {
  	return avc_cache.latest_notif;
  }
  
  void avc_disable(void)
  {
  	/*
  	 * If you are looking at this because you have realized that we are
  	 * not destroying the avc_node_cachep it might be easy to fix, but
  	 * I don't know the memory barrier semantics well enough to know.  It's
  	 * possible that some other task dereferenced security_ops when
  	 * it still pointed to selinux operations.  If that is the case it's
  	 * possible that it is about to use the avc and is about to need the
  	 * avc_node_cachep.  I know I could wrap the security.c security_ops call
  	 * in an rcu_lock, but seriously, it's not worth it.  Instead I just flush
  	 * the cache and get that memory back.
  	 */
  	if (avc_node_cachep) {
  		avc_flush();
  		/* kmem_cache_destroy(avc_node_cachep); */
  	}
  }