/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Access vector cache interface for object managers.
 *
 * Author : Stephen Smalley, <sds@tycho.nsa.gov>
 */
#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, int result,
                   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,
                            int flags)
{
        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, result,
                              a, flags);
}

#define AVC_STRICT 1 /* Ignore permissive mode. */
#define AVC_EXTENDED_PERMS 2    /* update extended permissions */
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);
int avc_has_perm_flags(u32 ssid, u32 tsid,
                       u16 tclass, u32 requested,
                       struct common_audit_data *auditdata,
                       int flags);

int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
                u8 driver, u8 perm, struct common_audit_data *ad);


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
#define AVC_CALLBACK_ADD_XPERMS         256

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_ */