/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * An access vector table (avtab) is a hash table
 * of access vectors and transition types indexed
 * by a type pair and a class.  An access vector
 * table is used to represent the type enforcement
 * tables.
 *
 *  Author : Stephen Smalley, <stephen.smalley.work@gmail.com>
 */

/* Updated: Frank Mayer <mayerf@tresys.com> and
 *          Karl MacMillan <kmacmillan@tresys.com>
 *          Added conditional policy language extensions
 *          Copyright (C) 2003 Tresys Technology, LLC
 *
 * Updated: Yuichi Nakamura <ynakam@hitachisoft.jp>
 *          Tuned number of hash slots for avtab to reduce memory usage
 */

#ifndef _SS_AVTAB_H_
#define _SS_AVTAB_H_

#include "security.h"

struct avtab_key {
        u16 source_type; /* source type */
        u16 target_type; /* target type */
        u16 target_class; /* target object class */
#define AVTAB_ALLOWED    0x0001
#define AVTAB_AUDITALLOW 0x0002
#define AVTAB_AUDITDENY  0x0004
#define AVTAB_AV         (AVTAB_ALLOWED | AVTAB_AUDITALLOW | AVTAB_AUDITDENY)
#define AVTAB_TRANSITION 0x0010
#define AVTAB_MEMBER     0x0020
#define AVTAB_CHANGE     0x0040
#define AVTAB_TYPE       (AVTAB_TRANSITION | AVTAB_MEMBER | AVTAB_CHANGE)
/* extended permissions */
#define AVTAB_XPERMS_ALLOWED    0x0100
#define AVTAB_XPERMS_AUDITALLOW 0x0200
#define AVTAB_XPERMS_DONTAUDIT  0x0400
#define AVTAB_XPERMS                                      \
        (AVTAB_XPERMS_ALLOWED | AVTAB_XPERMS_AUDITALLOW | \
         AVTAB_XPERMS_DONTAUDIT)
#define AVTAB_ENABLED_OLD 0x80000000 /* reserved for used in cond_avtab */
#define AVTAB_ENABLED     0x8000 /* reserved for used in cond_avtab */
        u16 specified; /* what field is specified */
};

/*
 * For operations that require more than the 32 permissions provided by the avc
 * extended permissions may be used to provide 256 bits of permissions.
 */
struct avtab_extended_perms {
/* These are not flags. All 256 values may be used */
#define AVTAB_XPERMS_IOCTLFUNCTION      0x01
#define AVTAB_XPERMS_IOCTLDRIVER        0x02
#define AVTAB_XPERMS_NLMSG              0x03
        /* extension of the avtab_key specified */
        u8 specified; /* ioctl, netfilter, ... */
        /*
         * if 256 bits is not adequate as is often the case with ioctls, then
         * multiple extended perms may be used and the driver field
         * specifies which permissions are included.
         */
        u8 driver;
        /* 256 bits of permissions */
        struct extended_perms_data perms;
};

struct avtab_datum {
        union {
                u32 data; /* access vector or type value */
                struct avtab_extended_perms *xperms;
        } u;
};

struct avtab_node {
        struct avtab_key key;
        struct avtab_datum datum;
        struct avtab_node *next;
};

struct avtab {
        struct avtab_node **htable;
        u32 nel; /* number of elements */
        u32 nslot; /* number of hash slots */
        u32 mask; /* mask to compute hash func */
};

void avtab_init(struct avtab *h);
int avtab_alloc(struct avtab *h, u32 nrules);
int avtab_alloc_dup(struct avtab *new, const struct avtab *orig);
void avtab_destroy(struct avtab *h);

#define MAX_AVTAB_HASH_BITS    16
#define MAX_AVTAB_HASH_BUCKETS (1 << MAX_AVTAB_HASH_BITS)

#ifdef CONFIG_SECURITY_SELINUX_DEBUG
void avtab_hash_eval(struct avtab *h, const char *tag);
#else
static inline void avtab_hash_eval(struct avtab *h, const char *tag)
{
}
#endif

struct policydb;
struct policy_file;
int avtab_read_item(struct avtab *a, struct policy_file *fp, struct policydb *pol,
                    int (*insert)(struct avtab *a, const struct avtab_key *k,
                                  const struct avtab_datum *d, void *p),
                    void *p, bool conditional);

int avtab_read(struct avtab *a, struct policy_file *fp, struct policydb *pol);
int avtab_write_item(struct policydb *p, const struct avtab_node *cur,
                     struct policy_file *fp);
int avtab_write(struct policydb *p, struct avtab *a, struct policy_file *fp);

struct avtab_node *avtab_insert_nonunique(struct avtab *h,
                                          const struct avtab_key *key,
                                          const struct avtab_datum *datum);

struct avtab_node *avtab_search_node(struct avtab *h,
                                     const struct avtab_key *key);
struct avtab_node *avtab_search_node_next(struct avtab_node *node,
                                          u16 specified);

#endif /* _SS_AVTAB_H_ */