michael@0: /*	$NetBSD: ns_samedomain.c,v 1.2 2004/05/20 20:35:05 christos Exp $	*/
michael@0: 
michael@0: /*
michael@0:  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
michael@0:  * Copyright (c) 1995,1999 by Internet Software Consortium.
michael@0:  *
michael@0:  * Permission to use, copy, modify, and distribute this software for any
michael@0:  * purpose with or without fee is hereby granted, provided that the above
michael@0:  * copyright notice and this permission notice appear in all copies.
michael@0:  *
michael@0:  * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES
michael@0:  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
michael@0:  * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC BE LIABLE FOR
michael@0:  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
michael@0:  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
michael@0:  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
michael@0:  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
michael@0:  */
michael@0: 
michael@0: /*
michael@0:  * This version of this file is derived from Android 2.3 "Gingerbread",
michael@0:  * which contains uncredited changes by Android/Google developers.  It has
michael@0:  * been modified in 2011 for use in the Android build of Mozilla Firefox by
michael@0:  * Mozilla contributors (including Michael Edwards <m.k.edwards@gmail.com>,
michael@0:  * and Steve Workman <sjhworkman@gmail.com>).
michael@0:  * These changes are offered under the same license as the original NetBSD
michael@0:  * file, whose copyright and license are unchanged above.
michael@0:  */
michael@0: 
michael@0: #define ANDROID_CHANGES 1
michael@0: #define MOZILLA_NECKO_EXCLUDE_CODE 1
michael@0: 
michael@0: #include <sys/cdefs.h>
michael@0: #ifndef lint
michael@0: #ifdef notdef
michael@0: static const char rcsid[] = "Id: ns_samedomain.c,v 1.1.2.2.4.2 2004/03/16 12:34:17 marka Exp";
michael@0: #else
michael@0: __RCSID("$NetBSD: ns_samedomain.c,v 1.2 2004/05/20 20:35:05 christos Exp $");
michael@0: #endif
michael@0: #endif
michael@0: 
michael@0: #include <sys/types.h>
michael@0: #include "arpa_nameser.h"
michael@0: #include <errno.h>
michael@0: #include <string.h>
michael@0: 
michael@0: #ifndef MOZILLA_NECKO_EXCLUDE_CODE
michael@0: #ifndef _LIBC
michael@0: /*
michael@0:  * int
michael@0:  * ns_samedomain(a, b)
michael@0:  *	Check whether a name belongs to a domain.
michael@0:  * Inputs:
michael@0:  *	a - the domain whose ancestory is being verified
michael@0:  *	b - the potential ancestor we're checking against
michael@0:  * Return:
michael@0:  *	boolean - is a at or below b?
michael@0:  * Notes:
michael@0:  *	Trailing dots are first removed from name and domain.
michael@0:  *	Always compare complete subdomains, not only whether the
michael@0:  *	domain name is the trailing string of the given name.
michael@0:  *
michael@0:  *	"host.foobar.top" lies in "foobar.top" and in "top" and in ""
michael@0:  *	but NOT in "bar.top"
michael@0:  */
michael@0: 
michael@0: int
michael@0: ns_samedomain(const char *a, const char *b) {
michael@0: 	size_t la, lb;
michael@0: 	int diff, i, escaped;
michael@0: 	const char *cp;
michael@0: 
michael@0: 	la = strlen(a);
michael@0: 	lb = strlen(b);
michael@0: 
michael@0: 	/* Ignore a trailing label separator (i.e. an unescaped dot) in 'a'. */
michael@0: 	if (la != 0U && a[la - 1] == '.') {
michael@0: 		escaped = 0;
michael@0: 		/* Note this loop doesn't get executed if la==1. */
michael@0: 		for (i = la - 2; i >= 0; i--)
michael@0: 			if (a[i] == '\\') {
michael@0: 				if (escaped)
michael@0: 					escaped = 0;
michael@0: 				else
michael@0: 					escaped = 1;
michael@0: 			} else
michael@0: 				break;
michael@0: 		if (!escaped)
michael@0: 			la--;
michael@0: 	}
michael@0: 
michael@0: 	/* Ignore a trailing label separator (i.e. an unescaped dot) in 'b'. */
michael@0: 	if (lb != 0U && b[lb - 1] == '.') {
michael@0: 		escaped = 0;
michael@0: 		/* note this loop doesn't get executed if lb==1 */
michael@0: 		for (i = lb - 2; i >= 0; i--)
michael@0: 			if (b[i] == '\\') {
michael@0: 				if (escaped)
michael@0: 					escaped = 0;
michael@0: 				else
michael@0: 					escaped = 1;
michael@0: 			} else
michael@0: 				break;
michael@0: 		if (!escaped)
michael@0: 			lb--;
michael@0: 	}
michael@0: 
michael@0: 	/* lb == 0 means 'b' is the root domain, so 'a' must be in 'b'. */
michael@0: 	if (lb == 0U)
michael@0: 		return (1);
michael@0: 
michael@0: 	/* 'b' longer than 'a' means 'a' can't be in 'b'. */
michael@0: 	if (lb > la)
michael@0: 		return (0);
michael@0: 
michael@0: 	/* 'a' and 'b' being equal at this point indicates sameness. */
michael@0: 	if (lb == la)
michael@0: 		return (strncasecmp(a, b, lb) == 0);
michael@0: 
michael@0: 	/* Ok, we know la > lb. */
michael@0: 
michael@0: 	diff = la - lb;
michael@0: 
michael@0: 	/*
michael@0: 	 * If 'a' is only 1 character longer than 'b', then it can't be
michael@0: 	 * a subdomain of 'b' (because of the need for the '.' label
michael@0: 	 * separator).
michael@0: 	 */
michael@0: 	if (diff < 2)
michael@0: 		return (0);
michael@0: 
michael@0: 	/*
michael@0: 	 * If the character before the last 'lb' characters of 'b'
michael@0: 	 * isn't '.', then it can't be a match (this lets us avoid
michael@0: 	 * having "foobar.com" match "bar.com").
michael@0: 	 */
michael@0: 	if (a[diff - 1] != '.')
michael@0: 		return (0);
michael@0: 
michael@0: 	/*
michael@0: 	 * We're not sure about that '.', however.  It could be escaped
michael@0:          * and thus not a really a label separator.
michael@0: 	 */
michael@0: 	escaped = 0;
michael@0: 	for (i = diff - 2; i >= 0; i--)
michael@0: 		if (a[i] == '\\') {
michael@0: 			if (escaped)
michael@0: 				escaped = 0;
michael@0: 			else
michael@0: 				escaped = 1;
michael@0: 		} else
michael@0: 			break;
michael@0: 	if (escaped)
michael@0: 		return (0);
michael@0: 
michael@0: 	/* Now compare aligned trailing substring. */
michael@0: 	cp = a + diff;
michael@0: 	return (strncasecmp(cp, b, lb) == 0);
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * int
michael@0:  * ns_subdomain(a, b)
michael@0:  *	is "a" a subdomain of "b"?
michael@0:  */
michael@0: int
michael@0: ns_subdomain(const char *a, const char *b) {
michael@0: 	return (ns_samename(a, b) != 1 && ns_samedomain(a, b));
michael@0: }
michael@0: #endif
michael@0: #endif
michael@0: 
michael@0: /*
michael@0:  * int
michael@0:  * ns_makecanon(src, dst, dstsize)
michael@0:  *	make a canonical copy of domain name "src"
michael@0:  * notes:
michael@0:  *	foo -> foo.
michael@0:  *	foo. -> foo.
michael@0:  *	foo.. -> foo.
michael@0:  *	foo\. -> foo\..
michael@0:  *	foo\\. -> foo\\.
michael@0:  */
michael@0: 
michael@0: int
michael@0: ns_makecanon(const char *src, char *dst, size_t dstsize) {
michael@0: 	size_t n = strlen(src);
michael@0: 
michael@0: 	if (n + sizeof "." > dstsize) {			/* Note: sizeof == 2 */
michael@0: 		errno = EMSGSIZE;
michael@0: 		return (-1);
michael@0: 	}
michael@0: 	strcpy(dst, src);
michael@0: 	while (n >= 1U && dst[n - 1] == '.')		/* Ends in "." */
michael@0: 		if (n >= 2U && dst[n - 2] == '\\' &&	/* Ends in "\." */
michael@0: 		    (n < 3U || dst[n - 3] != '\\'))	/* But not "\\." */
michael@0: 			break;
michael@0: 		else
michael@0: 			dst[--n] = '\0';
michael@0: 	dst[n++] = '.';
michael@0: 	dst[n] = '\0';
michael@0: 	return (0);
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * int
michael@0:  * ns_samename(a, b)
michael@0:  *	determine whether domain name "a" is the same as domain name "b"
michael@0:  * return:
michael@0:  *	-1 on error
michael@0:  *	0 if names differ
michael@0:  *	1 if names are the same
michael@0:  */
michael@0: 
michael@0: int
michael@0: ns_samename(const char *a, const char *b) {
michael@0: 	char ta[NS_MAXDNAME], tb[NS_MAXDNAME];
michael@0: 
michael@0: 	if (ns_makecanon(a, ta, sizeof ta) < 0 ||
michael@0: 	    ns_makecanon(b, tb, sizeof tb) < 0)
michael@0: 		return (-1);
michael@0: 	if (strcasecmp(ta, tb) == 0)
michael@0: 		return (1);
michael@0: 	else
michael@0: 		return (0);
michael@0: }