/*
   * Access vector cache interface for object managers.
   *
   * Author : Stephen Smalley, <sds@epoch.ncsc.mil>
   */
  #ifndef _SELINUX_AVC_H_
  #define _SELINUX_AVC_H_
  
  #include <linux/stddef.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/kdev_t.h>
  #include <linux/spinlock.h>
  #include <linux/init.h>
  #include <linux/audit.h>
  #include <linux/lsm_audit.h>
  #include <linux/in6.h>
  #include "flask.h"
  #include "av_permissions.h"
  #include "security.h"
  
  #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
  extern int selinux_enforcing;
  #else
  #define selinux_enforcing 1
  #endif
  
  /*
   * An entry in the AVC.
   */
  struct avc_entry;
  
  struct task_struct;
  struct inode;
  struct sock;
  struct sk_buff;
  
  /*
   * AVC statistics
   */
  struct avc_cache_stats {
  	unsigned int lookups;
  	unsigned int misses;
  	unsigned int allocations;
  	unsigned int reclaims;
  	unsigned int frees;
  };
  
  /*
   * We only need this data after we have decided to send an audit message.
   */
  struct selinux_audit_data {
  	u32 ssid;
  	u32 tsid;
  	u16 tclass;
  	u32 requested;
  	u32 audited;
  	u32 denied;
  	int result;
  };
  
  /*
   * AVC operations
   */
  
  void __init avc_init(void);
  
  static inline u32 avc_audit_required(u32 requested,
  			      struct av_decision *avd,
  			      int result,
  			      u32 auditdeny,
  			      u32 *deniedp)
  {
  	u32 denied, audited;
  	denied = requested & ~avd->allowed;
  	if (unlikely(denied)) {
  		audited = denied & avd->auditdeny;
  		/*
  		 * auditdeny is TRICKY!  Setting a bit in
  		 * this field means that ANY denials should NOT be audited if
  		 * the policy contains an explicit dontaudit rule for that
  		 * permission.  Take notice that this is unrelated to the
  		 * actual permissions that were denied.  As an example lets
  		 * assume:
  		 *
  		 * denied == READ
  		 * avd.auditdeny & ACCESS == 0 (not set means explicit rule)
  		 * auditdeny & ACCESS == 1
  		 *
  		 * We will NOT audit the denial even though the denied
  		 * permission was READ and the auditdeny checks were for
  		 * ACCESS
  		 */
  		if (auditdeny && !(auditdeny & avd->auditdeny))
  			audited = 0;
  	} else if (result)
  		audited = denied = requested;
  	else
  		audited = requested & avd->auditallow;
  	*deniedp = denied;
  	return audited;
  }
  
  int slow_avc_audit(u32 ssid, u32 tsid, u16 tclass,
  		   u32 requested, u32 audited, u32 denied,
  		   struct common_audit_data *a,
  		   unsigned flags);
  
  /**
   * avc_audit - Audit the granting or denial of permissions.
   * @ssid: source security identifier
   * @tsid: target security identifier
   * @tclass: target security class
   * @requested: requested permissions
   * @avd: access vector decisions
   * @result: result from avc_has_perm_noaudit
   * @a:  auxiliary audit data
   * @flags: VFS walk flags
   *
   * Audit the granting or denial of permissions in accordance
   * with the policy.  This function is typically called by
   * avc_has_perm() after a permission check, but can also be
   * called directly by callers who use avc_has_perm_noaudit()
   * in order to separate the permission check from the auditing.
   * For example, this separation is useful when the permission check must
   * be performed under a lock, to allow the lock to be released
   * before calling the auditing code.
   */
  static inline int avc_audit(u32 ssid, u32 tsid,
  			    u16 tclass, u32 requested,
  			    struct av_decision *avd,
  			    int result,
  			    struct common_audit_data *a)
  {
  	u32 audited, denied;
  	audited = avc_audit_required(requested, avd, result, 0, &denied);
  	if (likely(!audited))
  		return 0;
  	return slow_avc_audit(ssid, tsid, tclass,
  			      requested, audited, denied,
  			      a, 0);
  }
  
  #define AVC_STRICT 1 /* Ignore permissive mode. */
  int avc_has_perm_noaudit(u32 ssid, u32 tsid,
  			 u16 tclass, u32 requested,
  			 unsigned flags,
  			 struct av_decision *avd);
  
  int avc_has_perm(u32 ssid, u32 tsid,
  		 u16 tclass, u32 requested,
  		 struct common_audit_data *auditdata);
  
  u32 avc_policy_seqno(void);
  
  #define AVC_CALLBACK_GRANT		1
  #define AVC_CALLBACK_TRY_REVOKE		2
  #define AVC_CALLBACK_REVOKE		4
  #define AVC_CALLBACK_RESET		8
  #define AVC_CALLBACK_AUDITALLOW_ENABLE	16
  #define AVC_CALLBACK_AUDITALLOW_DISABLE	32
  #define AVC_CALLBACK_AUDITDENY_ENABLE	64
  #define AVC_CALLBACK_AUDITDENY_DISABLE	128
  
  int avc_add_callback(int (*callback)(u32 event), u32 events);
  
  /* Exported to selinuxfs */
  int avc_get_hash_stats(char *page);
  extern unsigned int avc_cache_threshold;
  
  /* Attempt to free avc node cache */
  void avc_disable(void);
  
  #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
  DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
  #endif
  
  #endif /* _SELINUX_AVC_H_ */