Initial import

1 files changed, 792 insertions, 0 deletions

diff --git a/security/selinux/avc.c b/security/selinux/avc.c
new file mode 100644
index 000000000..3c17dda95
--- /dev/null
+++ b/security/selinux/avc.c
@@ -0,0 +1,792 @@
+/*
+ * 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\n");
+}
+
+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\nbuckets used: %d/%d\n"
+			 "longest chain: %d\n",
+			 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\n",
+			       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);
+	if (ad->selinux_audit_data->denied) {
+		audit_log_format(ab, " permissive=%u",
+				 ad->selinux_audit_data->result ? 0 : 1);
+	}
+}
+
+/* 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, int result,
+		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;
+	sad.result = result;
+
+	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;
+}
+
+/**
+ * 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));
+
+	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); */
+	}
+}