HardenedBSD/contrib/bind/bin/named/db_lookup.c

#if !defined(lint) && !defined(SABER)
static const char sccsid[] = "@(#)db_lookup.c	4.18 (Berkeley) 3/21/91";
static const char rcsid[] = "$Id: db_lookup.c,v 8.26 2000/04/21 06:54:03 vixie Exp $";
#endif /* not lint */

/*
 * Copyright (c) 1986
 *    The Regents of the University of California.  All rights reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 * 	This product includes software developed by the University of
 * 	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Portions Copyright (c) 1993 by Digital Equipment Corporation.
 * 
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies, and that
 * the name of Digital Equipment Corporation not be used in advertising or
 * publicity pertaining to distribution of the document or software without
 * specific, written prior permission.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS" AND DIGITAL EQUIPMENT CORP. DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS.   IN NO EVENT SHALL DIGITAL EQUIPMENT
 * CORPORATION BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/*
 * Portions Copyright (c) 1996-2000 by Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM DISCLAIMS
 * ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL INTERNET SOFTWARE
 * CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL
 * DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
 * PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
 * ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
 * SOFTWARE.
 */

/*
 * Table lookup routines.
 */

#include "port_before.h"

#include <sys/types.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/un.h>

#include <netinet/in.h>
#include <arpa/nameser.h>

#include <ctype.h>
#include <stdio.h>
#include <string.h>
#include <syslog.h>
#include <time.h>

#include <isc/eventlib.h>
#include <isc/logging.h>

#include "port_after.h"

#include "named.h"

/* 
 * Lookup 'name' and return a pointer to the namebuf;
 * NULL otherwise. If 'insert', insert name into tables.
 * Wildcard lookups are handled.
 */
struct namebuf *
nlookup(const char *name, struct hashbuf **htpp,
	const char **fname, int insert)
{
	struct namebuf *np;
	const char *cp;
	int c;
	u_int hval;
	struct hashbuf *htp;
	struct namebuf *parent = NULL;
	int escaped = 0;

	htp = *htpp;
	hval = 0;
	*fname = "???";
	for (cp = name; (c = *cp++) != 0; (void)NULL) {
		if (!escaped && (c == '.')) {
			parent = np = nlookup(cp, htpp, fname, insert);
			if (np == NULL)
				return (NULL);
			if (*fname != cp)
				return (np);
			if ((htp = np->n_hash) == NULL) {
				if (!insert) {
					if (ns_wildcard(NAME(*np)))
						*fname = name;
					return (np);
				}
				htp = savehash((struct hashbuf *)NULL);
				np->n_hash = htp;
			}
			*htpp = htp;
			break;
		}

		HASHIMILATE(hval, c);
		if (escaped)
			escaped = 0;
		else if (c == '\\')
			escaped = 1;
	}
	cp--;
	/*
	 * Lookup this label in current hash table.
	 */
	for (np = htp->h_tab[hval % htp->h_size];
	     np != NULL;
	     np = np->n_next) {
		if (np->n_hashval == hval &&
		    ((size_t)NAMELEN(*np) == (size_t)(cp - name)) && 
		    (strncasecmp(name, NAME(*np), cp - name) == 0)) {
			*fname = name;
			return (np);
		}
	}
	if (!insert) {
		/*
		 * Look for wildcard in this hash table.
		 * Don't use a cached "*" name as a wildcard,
		 * only authoritative.
		 */
		hval = ('*' & HASHMASK) % htp->h_size;
		for (np = htp->h_tab[hval]; np != NULL; np = np->n_next) {
			if (ns_wildcard(NAME(*np)) &&
			    np->n_data && np->n_data->d_zone != 0) {
				*fname = name;
				return (np);
			}
		}
		return (parent);
	}
	np = savename(name, cp - name);
	np->n_parent = parent;
	np->n_hashval = hval;
	hval %= htp->h_size;
	np->n_next = htp->h_tab[hval];
	htp->h_tab[hval] = np;
	/* Increase hash table size. */
	if (++htp->h_cnt > (htp->h_size * AVGCH_NLOOKUP)) {
		*htpp = savehash(htp);
		if (parent == NULL) {
			if (htp == hashtab) {
				hashtab = *htpp;
			} else {
				fcachetab = *htpp;
		        }
		}
		else
			parent->n_hash = *htpp;
		htp = *htpp;
	}
	*fname = name;
	return (np);
}

/* struct namebuf *
 * np_parent(struct namebuf *np)
 *	Find the "parent" namebuf of np.
 *	This is tricky since the parent of "com" is "" and both are stored
 *	in the same hashbuf.
 * See also:
 *	the AXFR wart description in ns_axfr.c
 */
struct namebuf *
np_parent(struct namebuf *np) {
	struct hashbuf *htp;
	struct namebuf *np2;

	if (np->n_parent != NULL || NAME(*np)[0] == '\0')
		return (np->n_parent);

	/* Try to figure out if np is pointing into the cache or hints. */
	/* Try the cache first. */
	htp = hashtab;
 try_again:
	/* Search the hash chain that np should be part of. */
	for (np2 = htp->h_tab[np->n_hashval % htp->h_size];
	     np2 != NULL;
	     np2 = np2->n_next)
	{
		if (np == np2) {	/* found it! */
			/* "" hashes into the first bucket */
			for (np = htp->h_tab[0]; np != NULL; np = np->n_next) {
				if (NAME(*np)[0] == '\0')
					/* found the root namebuf */
					return (np);
			}
			/* there are no RR's with a owner name of "." yet */
			return (NULL);
		}
	}
	/* Try the hints. */
	if (htp == hashtab) {
		htp = fcachetab;
		goto try_again;
	}
	ns_debug(ns_log_db, 1, "np_parent(0x%lx) couldn't find namebuf",
		 (u_long)np);
	return (NULL);  /* XXX shouldn't happen */
}

/* int
 * match(dp, class, type)
 *	Does data record `dp' match the class and type?
 * return value:
 *	boolean
 */
int
match(struct databuf *dp, int class, int type) {
	if (dp->d_class != class && class != C_ANY)
		return (0);
	if (dp->d_type != type && dp->d_type != T_SIG && type != T_ANY)
		return (0);
	if (type != T_SIG && dp->d_type == T_SIG && SIG_COVERS(dp) != type)
		return (0);
	return (1);
}

/* static int
 * nxtlower(name, dp)
 *	Is the NXT/SIG NXT record 'lower'?
 * return value:
 *	boolean
 */
static int
nxtlower(const char *name, struct databuf *dp) {
	/* An NXT is a lower NXT iff the SOA bit is set in the bitmap */
	if (dp->d_type == T_NXT) {
		u_char *nxtbitmap = dp->d_data + strlen((char *)dp->d_data) + 1;
		return (NS_NXT_BIT_ISSET(T_SOA, nxtbitmap) ? 1 : 0);
	}
	/* If it's not an NXT, it's a SIG NXT.  An NXT record must be signed
	 * by the zone, so the signer name must be the same as the owner.
	 */
	return (ns_samename(name, (char *)dp->d_data + SIG_HDR_SIZE) != 1 ? 0 : 1);
}   

/* int
 * nxtmatch(name, dp1, dp2)
 *	Do NXT/SIG NXT records `dp1' and `dp2' belong to the same NXT set?
 * return value:
 *	boolean
 */
int
nxtmatch(const char *name, struct databuf *dp1, struct databuf *dp2) {
        int dp1_lower, dp2_lower;
	int type1, type2;

	if (dp1->d_type == ns_t_sig)
		type1 = SIG_COVERS(dp1);
	else
		type1 = dp1->d_type;
	if (dp2->d_type == ns_t_sig)
		type2 = SIG_COVERS(dp2);
	else
		type2 = dp2->d_type;

	if (type1 != ns_t_nxt || type2 != ns_t_nxt)
		return (0);
        dp1_lower = nxtlower(name, dp1);
        dp2_lower = nxtlower(name, dp2);
        return (dp1_lower == dp2_lower); 
}

/* int
 * rrmatch(name, dp1, dp2)
 *	Do data records `dp1' and `dp2' match in class and type?
 *	If both are NXTs, do they belong in the same NXT set?
 *	If both are SIGs, do the covered types match?
 *	If both are SIG NXTs, do the covered NXTs belong in the same set?
 *	Why is DNSSEC so confusing?
 * return value:
 *	boolean
 */
int
rrmatch(const char *name, struct databuf *dp1, struct databuf *dp2) {
	if (dp1->d_class != dp2->d_class &&
	    dp1->d_class != C_ANY && dp2->d_class != C_ANY)
		return(0);
	if (dp1->d_type != dp2->d_type &&
	    dp1->d_type != T_ANY && dp2->d_type != T_ANY)
		return(0);
	if (dp1->d_type == T_NXT)
		return(nxtmatch(name, dp1, dp2));
	if (dp1->d_type != T_SIG)
		return(1);
	if (SIG_COVERS(dp1) == SIG_COVERS(dp2)) {
		if (SIG_COVERS(dp1) == ns_t_nxt)
			return(nxtmatch(name, dp1, dp2));
		else
			return(1);
	}
	return(0);
}