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, <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
	/* 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);
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;
int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol,
		    int (*insert)(struct avtab *a, const struct avtab_key *k,
				  const 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, const 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,
					  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_ */