[BACK]Return to ns_samedomain.c CVS log [TXT][DIR] Up to [cvs.NetBSD.org] / src / lib / libc / nameser

File: [cvs.NetBSD.org] / src / lib / libc / nameser / ns_samedomain.c (download)

Revision 1.8, Thu Nov 22 20:22:31 2012 UTC (7 years, 11 months ago) by christos
Branch: MAIN
CVS Tags: yamt-pagecache-base9, yamt-pagecache-base8, yamt-pagecache-base7, tls-maxphys-base, tls-earlyentropy-base, tls-earlyentropy, riastradh-xf86-video-intel-2-7-1-pre-2-21-15, riastradh-drm2-base3, riastradh-drm2-base2, riastradh-drm2-base1, riastradh-drm2-base, riastradh-drm2, prg-localcount2-base3, prg-localcount2-base2, prg-localcount2-base1, prg-localcount2-base, prg-localcount2, phil-wifi-base, phil-wifi-20200421, phil-wifi-20200411, phil-wifi-20200406, phil-wifi-20191119, phil-wifi-20190609, phil-wifi, pgoyette-localcount-base, pgoyette-localcount-20170426, pgoyette-localcount-20170320, pgoyette-localcount-20170107, pgoyette-localcount-20161104, pgoyette-localcount-20160806, pgoyette-localcount-20160726, pgoyette-localcount, pgoyette-compat-merge-20190127, pgoyette-compat-base, pgoyette-compat-20190127, pgoyette-compat-20190118, pgoyette-compat-1226, pgoyette-compat-1126, pgoyette-compat-1020, pgoyette-compat-0930, pgoyette-compat-0906, pgoyette-compat-0728, pgoyette-compat-0625, pgoyette-compat-0521, pgoyette-compat-0502, pgoyette-compat-0422, pgoyette-compat-0415, pgoyette-compat-0407, pgoyette-compat-0330, pgoyette-compat-0322, pgoyette-compat-0315, pgoyette-compat, perseant-stdc-iso10646-base, perseant-stdc-iso10646, netbsd-9-base, netbsd-9-1-RELEASE, netbsd-9-0-RELEASE, netbsd-9-0-RC2, netbsd-9-0-RC1, netbsd-9, netbsd-8-base, netbsd-8-2-RELEASE, netbsd-8-1-RELEASE, netbsd-8-1-RC1, netbsd-8-0-RELEASE, netbsd-8-0-RC2, netbsd-8-0-RC1, netbsd-8, netbsd-7-nhusb-base-20170116, netbsd-7-nhusb-base, netbsd-7-nhusb, netbsd-7-base, netbsd-7-2-RELEASE, netbsd-7-1-RELEASE, netbsd-7-1-RC2, netbsd-7-1-RC1, netbsd-7-1-2-RELEASE, netbsd-7-1-1-RELEASE, netbsd-7-1, netbsd-7-0-RELEASE, netbsd-7-0-RC3, netbsd-7-0-RC2, netbsd-7-0-RC1, netbsd-7-0-2-RELEASE, netbsd-7-0-1-RELEASE, netbsd-7-0, netbsd-7, matt-nb8-mediatek-base, matt-nb8-mediatek, localcount-20160914, is-mlppp-base, is-mlppp, bouyer-socketcan-base1, bouyer-socketcan-base, bouyer-socketcan, agc-symver-base, agc-symver, HEAD
Changes since 1.7: +4 -4 lines

don't compile the libc stuff twice.

/*	$NetBSD: ns_samedomain.c,v 1.8 2012/11/22 20:22:31 christos Exp $	*/

/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1995,1999 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 ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

#include <sys/cdefs.h>
#ifndef lint
#ifdef notdef
static const char rcsid[] = "Id: ns_samedomain.c,v 1.6 2005/04/27 04:56:40 sra Exp";
#else
__RCSID("$NetBSD: ns_samedomain.c,v 1.8 2012/11/22 20:22:31 christos Exp $");
#endif
#endif

#include "port_before.h"

#include <sys/types.h>
#include <arpa/nameser.h>
#include <errno.h>
#include <string.h>

#include "port_after.h"

#ifdef _LIBRESOLV
/*%
 *	Check whether a name belongs to a domain.
 *
 * Inputs:
 *\li	a - the domain whose ancestory is being verified
 *\li	b - the potential ancestor we're checking against
 *
 * Return:
 *\li	boolean - is a at or below b?
 *
 * Notes:
 *\li	Trailing dots are first removed from name and domain.
 *	Always compare complete subdomains, not only whether the
 *	domain name is the trailing string of the given name.
 *
 *\li	"host.foobar.top" lies in "foobar.top" and in "top" and in ""
 *	but NOT in "bar.top"
 */

int
ns_samedomain(const char *a, const char *b) {
	size_t la, lb, i;
	int diff, escaped;
	const char *cp;

	la = strlen(a);
	lb = strlen(b);

	/* Ignore a trailing label separator (i.e. an unescaped dot) in 'a'. */
	if (la != 0U && a[la - 1] == '.') {
		escaped = 0;
		/* Note this loop doesn't get executed if la==1. */
		for (i = la - 1; i > 0; i--)
			if (a[i - 1] == '\\') {
				if (escaped)
					escaped = 0;
				else
					escaped = 1;
			} else
				break;
		if (!escaped)
			la--;
	}

	/* Ignore a trailing label separator (i.e. an unescaped dot) in 'b'. */
	if (lb != 0U && b[lb - 1] == '.') {
		escaped = 0;
		/* note this loop doesn't get executed if lb==1 */
		for (i = lb - 1; i > 0; i--)
			if (b[i - 1] == '\\') {
				if (escaped)
					escaped = 0;
				else
					escaped = 1;
			} else
				break;
		if (!escaped)
			lb--;
	}

	/* lb == 0 means 'b' is the root domain, so 'a' must be in 'b'. */
	if (lb == 0U)
		return (1);

	/* 'b' longer than 'a' means 'a' can't be in 'b'. */
	if (lb > la)
		return (0);

	/* 'a' and 'b' being equal at this point indicates sameness. */
	if (lb == la)
		return (strncasecmp(a, b, lb) == 0);

	/* Ok, we know la > lb. */

	diff = (int)(la - lb);

	/*
	 * If 'a' is only 1 character longer than 'b', then it can't be
	 * a subdomain of 'b' (because of the need for the '.' label
	 * separator).
	 */
	if (diff < 2)
		return (0);

	/*
	 * If the character before the last 'lb' characters of 'b'
	 * isn't '.', then it can't be a match (this lets us avoid
	 * having "foobar.com" match "bar.com").
	 */
	if (a[diff - 1] != '.')
		return (0);

	/*
	 * We're not sure about that '.', however.  It could be escaped
         * and thus not a really a label separator.
	 */
	escaped = 0;
	for (i = diff - 1; i > 0; i--)
		if (a[i - 1] == '\\') {
			if (escaped)
				escaped = 0;
			else
				escaped = 1;
		} else
			break;
	if (escaped)
		return (0);
	  
	/* Now compare aligned trailing substring. */
	cp = a + diff;
	return (strncasecmp(cp, b, lb) == 0);
}

/*%
 *	is "a" a subdomain of "b"?
 */
int
ns_subdomain(const char *a, const char *b) {
	return (ns_samename(a, b) != 1 && ns_samedomain(a, b));
}
#endif
#ifdef _LIBC
/*%
 *	make a canonical copy of domain name "src"
 *
 * notes:
 * \code
 *	foo -> foo.
 *	foo. -> foo.
 *	foo.. -> foo.
 *	foo\. -> foo\..
 *	foo\\. -> foo\\.
 * \endcode
 */

int
ns_makecanon(const char *src, char *dst, size_t dstsize) {
	size_t n = strlen(src);

	if (n + sizeof "." > dstsize) {			/*%< Note: sizeof == 2 */
		errno = EMSGSIZE;
		return (-1);
	}
	strcpy(dst, src);
	while (n >= 1U && dst[n - 1] == '.')		/*%< Ends in "." */
		if (n >= 2U && dst[n - 2] == '\\' &&	/*%< Ends in "\." */
		    (n < 3U || dst[n - 3] != '\\'))	/*%< But not "\\." */
			break;
		else
			dst[--n] = '\0';
	dst[n++] = '.';
	dst[n] = '\0';
	return (0);
}

/*%
 *	determine whether domain name "a" is the same as domain name "b"
 *
 * return:
 *\li	-1 on error
 *\li	0 if names differ
 *\li	1 if names are the same
 */

int
ns_samename(const char *a, const char *b) {
	char ta[NS_MAXDNAME], tb[NS_MAXDNAME];

	if (ns_makecanon(a, ta, sizeof ta) < 0 ||
	    ns_makecanon(b, tb, sizeof tb) < 0)
		return (-1);
	if (strcasecmp(ta, tb) == 0)
		return (1);
	else
		return (0);
}
#endif
/*! \file */