linux/security/selinux/ss/avtab.h

/* 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, <sds@tycho.nsa.gov>
 */

/* 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
	/* 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 *, u32);
struct avtab_datum *avtab_search(struct avtab *h, struct avtab_key *k);
void avtab_destroy(struct avtab *h);
void avtab_hash_eval(struct avtab *h, char *tag);

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

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

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

struct avtab_node *avtab_search_node(struct avtab *h, struct avtab_key *key);

struct avtab_node *avtab_search_node_next(struct avtab_node *node, int specified);

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

#endif	/* _SS_AVTAB_H_ */