/* SPDX-License-Identifier: GPL-2.0 */
/*
 * Access vector cache interface for object managers.
 *
 * Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
 */

#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"

/*
 * 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;
} __randomize_layout;

/*
 * 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;

        if (avd->flags & AVD_FLAGS_NEVERAUDIT)
                return 0;

        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);

/**
 * 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
 *
 * 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,
                              result, a);
}

#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 int flags, struct av_decision *avd);

int avc_has_perm(u32 ssid, u32 tsid, u16 tclass, u32 requested,
                 struct common_audit_data *auditdata);

#define AVC_EXT_IOCTL   (1 << 0) /* Cache entry for an ioctl extended permission */
#define AVC_EXT_NLMSG   (1 << 1) /* Cache entry for an nlmsg extended permission */
int avc_has_extended_perms(u32 ssid, u32 tsid, u16 tclass, u32 requested,
                           u8 driver, u8 base_perm, 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);
unsigned int avc_get_cache_threshold(void);
void avc_set_cache_threshold(unsigned int cache_threshold);

#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
DECLARE_PER_CPU(struct avc_cache_stats, avc_cache_stats);
#endif

#endif /* _SELINUX_AVC_H_ */