Mini Shell

/*
 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, you can obtain one at https://mozilla.org/MPL/2.0/.
 *
 * See the COPYRIGHT file distributed with this work for additional
 * information regarding copyright ownership.
 */

#ifndef DNS_ACL_H
#define DNS_ACL_H 1

/*****
 ***** Module Info
 *****/

/*! \file dns/acl.h
 * \brief
 * Address match list handling.
 */

/***
 *** Imports
 ***/

#include <stdbool.h>

#include <isc/lang.h>
#include <isc/magic.h>
#include <isc/netaddr.h>
#include <isc/refcount.h>

#if defined(HAVE_GEOIP) || defined(HAVE_GEOIP2)
#include <dns/geoip.h>
#endif
#include <dns/name.h>
#include <dns/types.h>
#include <dns/iptable.h>

/***
 *** Types
 ***/

typedef enum {
	dns_aclelementtype_ipprefix,
	dns_aclelementtype_keyname,
	dns_aclelementtype_nestedacl,
	dns_aclelementtype_localhost,
	dns_aclelementtype_localnets,
#if defined(HAVE_GEOIP) || defined(HAVE_GEOIP2)
	dns_aclelementtype_geoip,
#endif /* HAVE_GEOIP || HAVE_GEOIP2 */
	dns_aclelementtype_any
} dns_aclelementtype_t;

typedef struct dns_aclipprefix dns_aclipprefix_t;

struct dns_aclipprefix {
	isc_netaddr_t address; /* IP4/IP6 */
	unsigned int prefixlen;
};

struct dns_aclelement {
	dns_aclelementtype_t	type;
	bool		negative;
	dns_name_t		keyname;
#if defined(HAVE_GEOIP) || defined(HAVE_GEOIP2)
	dns_geoip_elem_t	geoip_elem;
#endif /* HAVE_GEOIP || HAVE_GEOIP2 */
	dns_acl_t		*nestedacl;
	int			node_num;
};

#define dns_acl_node_count(acl) acl->iptable->radix->num_added_node

struct dns_acl {
	unsigned int		magic;
	isc_mem_t		*mctx;
	isc_refcount_t		refcount;
	dns_iptable_t		*iptable;
	dns_aclelement_t	*elements;
	bool			has_negatives;
	unsigned int		alloc;		/*%< Elements allocated */
	unsigned int		length;		/*%< Elements initialized */
	char			*name;		/*%< Temporary use only */
	ISC_LINK(dns_acl_t)	nextincache;	/*%< Ditto */
};

struct dns_aclenv {
	dns_acl_t *localhost;
	dns_acl_t *localnets;
	bool match_mapped;
#if defined(HAVE_GEOIP) || defined(HAVE_GEOIP2)
	dns_geoip_databases_t *geoip;
	bool geoip_use_ecs;
#endif
};

#define DNS_ACL_MAGIC		ISC_MAGIC('D','a','c','l')
#define DNS_ACL_VALID(a)	ISC_MAGIC_VALID(a, DNS_ACL_MAGIC)

/***
 *** Functions
 ***/

ISC_LANG_BEGINDECLS

isc_result_t
dns_acl_create(isc_mem_t *mctx, int n, dns_acl_t **target);
/*%<
 * Create a new ACL, including an IP table and an array with room
 * for 'n' ACL elements.  The elements are uninitialized and the
 * length is 0.
 */

isc_result_t
dns_acl_any(isc_mem_t *mctx, dns_acl_t **target);
/*%<
 * Create a new ACL that matches everything.
 */

isc_result_t
dns_acl_none(isc_mem_t *mctx, dns_acl_t **target);
/*%<
 * Create a new ACL that matches nothing.
 */

bool
dns_acl_isany(dns_acl_t *acl);
/*%<
 * Test whether ACL is set to "{ any; }"
 */

bool
dns_acl_isnone(dns_acl_t *acl);
/*%<
 * Test whether ACL is set to "{ none; }"
 */

isc_result_t
dns_acl_merge(dns_acl_t *dest, dns_acl_t *source, bool pos);
/*%<
 * Merge the contents of one ACL into another.  Call dns_iptable_merge()
 * for the IP tables, then concatenate the element arrays.
 *
 * If pos is set to false, then the nested ACL is to be negated.  This
 * means reverse the sense of each *positive* element or IP table node,
 * but leave negatives alone, so as to prevent a double-negative causing
 * an unexpected positive match in the parent ACL.
 */

void
dns_acl_attach(dns_acl_t *source, dns_acl_t **target);
/*%<
 * Attach to acl 'source'.
 *
 * Requires:
 *\li	'source' to be a valid acl.
 *\li	'target' to be non NULL and '*target' to be NULL.
 */

void
dns_acl_detach(dns_acl_t **aclp);
/*%<
 * Detach the acl. On final detach the acl must not be linked on any
 * list.
 *
 * Requires:
 *\li	'*aclp' to be a valid acl.
 *
 * Insists:
 *\li	'*aclp' is not linked on final detach.
 */

bool
dns_acl_isinsecure(const dns_acl_t *a);
/*%<
 * Return #true iff the acl 'a' is considered insecure, that is,
 * if it contains IP addresses other than those of the local host.
 * This is intended for applications such as printing warning
 * messages for suspect ACLs; it is not intended for making access
 * control decisions.  We make no guarantee that an ACL for which
 * this function returns #false is safe.
 */

isc_result_t
dns_aclenv_init(isc_mem_t *mctx, dns_aclenv_t *env);
/*%<
 * Initialize ACL environment, setting up localhost and localnets ACLs
 */

void
dns_aclenv_copy(dns_aclenv_t *t, dns_aclenv_t *s);

void
dns_aclenv_destroy(dns_aclenv_t *env);

isc_result_t
dns_acl_match(const isc_netaddr_t *reqaddr,
	      const dns_name_t *reqsigner,
	      const dns_acl_t *acl,
	      const dns_aclenv_t *env,
	      int *match,
	      const dns_aclelement_t **matchelt);

isc_result_t
dns_acl_match2(const isc_netaddr_t *reqaddr,
	       const dns_name_t *reqsigner,
	       const isc_netaddr_t *ecs,
	       uint8_t ecslen,
	       uint8_t *scope,
	       const dns_acl_t *acl,
	       const dns_aclenv_t *env,
	       int *match,
	       const dns_aclelement_t **matchelt);
/*%<
 * General, low-level ACL matching.  This is expected to
 * be useful even for weird stuff like the topology and sortlist statements.
 *
 * Match the address 'reqaddr', and optionally the key name 'reqsigner',
 * and optionally the client prefix 'ecs' of length 'ecslen'
 * (reported via EDNS client subnet option) against 'acl'.
 *
 * 'reqsigner' and 'ecs' may be NULL.  If an ACL matches against 'ecs'
 * and 'ecslen', then 'scope' will be set to indicate the netmask that
 * matched.
 *
 * If there is a match, '*match' will be set to an integer whose absolute
 * value corresponds to the order in which the matching value was inserted
 * into the ACL.  For a positive match, this value will be positive; for a
 * negative match, it will be negative.
 *
 * If there is no match, *match will be set to zero.
 *
 * If there is a match in the element list (either positive or negative)
 * and 'matchelt' is non-NULL, *matchelt will be pointed to the matching
 * element.
 *
 * 'env' points to the current ACL environment, including the
 * current values of localhost and localnets and (if applicable)
 * the GeoIP context.
 *
 * Returns:
 *\li	#ISC_R_SUCCESS		Always succeeds.
 */

bool
dns_aclelement_match(const isc_netaddr_t *reqaddr,
		     const dns_name_t *reqsigner,
		     const dns_aclelement_t *e,
		     const dns_aclenv_t *env,
		     const dns_aclelement_t **matchelt);

bool
dns_aclelement_match2(const isc_netaddr_t *reqaddr,
		      const dns_name_t *reqsigner,
		      const isc_netaddr_t *ecs,
		      uint8_t ecslen,
		      uint8_t *scope,
		      const dns_aclelement_t *e,
		      const dns_aclenv_t *env,
		      const dns_aclelement_t **matchelt);
/*%<
 * Like dns_acl_match, but matches against the single ACL element 'e'
 * rather than a complete ACL, and returns true iff it matched.
 *
 * To determine whether the match was positive or negative, the
 * caller should examine e->negative.  Since the element 'e' may be
 * a reference to a named ACL or a nested ACL, a matching element
 * returned through 'matchelt' is not necessarily 'e' itself.
 */

ISC_LANG_ENDDECLS

#endif /* DNS_ACL_H */