rcmd.c revision 331722
1/*
2 * Copyright (c) 1983, 1993, 1994
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 4. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#if defined(LIBC_SCCS) && !defined(lint)
31static char sccsid[] = "@(#)rcmd.c	8.3 (Berkeley) 3/26/94";
32#endif /* LIBC_SCCS and not lint */
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: stable/11/lib/libc/net/rcmd.c 331722 2018-03-29 02:50:57Z eadler $");
35
36#include "namespace.h"
37#include <sys/param.h>
38#include <sys/socket.h>
39#include <sys/stat.h>
40
41#include <netinet/in.h>
42#include <arpa/inet.h>
43
44#include <signal.h>
45#include <fcntl.h>
46#include <netdb.h>
47#include <stdlib.h>
48#include <unistd.h>
49#include <pwd.h>
50#include <errno.h>
51#include <stdio.h>
52#include <ctype.h>
53#include <string.h>
54#include <rpc/rpc.h>
55#ifdef YP
56#include <rpcsvc/yp_prot.h>
57#include <rpcsvc/ypclnt.h>
58#endif
59#include <arpa/nameser.h>
60#include "un-namespace.h"
61#include "libc_private.h"
62
63extern int innetgr( const char *, const char *, const char *, const char * );
64
65#define max(a, b)	((a > b) ? a : b)
66
67int __ivaliduser(FILE *, u_int32_t, const char *, const char *);
68int __ivaliduser_af(FILE *,const void *, const char *, const char *, int, int);
69int __ivaliduser_sa(FILE *, const struct sockaddr *, socklen_t, const char *,
70    const char *);
71static int __icheckhost(const struct sockaddr *, socklen_t, const char *);
72
73char paddr[NI_MAXHOST];
74
75int
76rcmd(char **ahost, int rport, const char *locuser, const char *remuser,
77    const char *cmd, int *fd2p)
78{
79	return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
80}
81
82int
83rcmd_af(char **ahost, int rport, const char *locuser, const char *remuser,
84    const char *cmd, int *fd2p, int af)
85{
86	struct addrinfo hints, *res, *ai;
87	struct sockaddr_storage from;
88	fd_set reads;
89	sigset_t oldmask, newmask;
90	pid_t pid;
91	int s, aport, lport, timo, error;
92	char c, *p;
93	int refused, nres;
94	char num[8];
95	static char canonnamebuf[MAXDNAME];	/* is it proper here? */
96
97	/* call rcmdsh() with specified remote shell if appropriate. */
98	if (!issetugid() && (p = getenv("RSH"))) {
99		struct servent *sp = getservbyname("shell", "tcp");
100
101		if (sp && sp->s_port == rport)
102			return (rcmdsh(ahost, rport, locuser, remuser,
103			    cmd, p));
104	}
105
106	/* use rsh(1) if non-root and remote port is shell. */
107	if (geteuid()) {
108		struct servent *sp = getservbyname("shell", "tcp");
109
110		if (sp && sp->s_port == rport)
111			return (rcmdsh(ahost, rport, locuser, remuser,
112			    cmd, NULL));
113	}
114
115	pid = getpid();
116
117	memset(&hints, 0, sizeof(hints));
118	hints.ai_flags = AI_CANONNAME;
119	hints.ai_family = af;
120	hints.ai_socktype = SOCK_STREAM;
121	hints.ai_protocol = 0;
122	(void)snprintf(num, sizeof(num), "%d", ntohs(rport));
123	error = getaddrinfo(*ahost, num, &hints, &res);
124	if (error) {
125		fprintf(stderr, "rcmd: getaddrinfo: %s\n",
126			gai_strerror(error));
127		if (error == EAI_SYSTEM)
128			fprintf(stderr, "rcmd: getaddrinfo: %s\n",
129				strerror(errno));
130		return (-1);
131	}
132
133	if (res->ai_canonname
134	 && strlen(res->ai_canonname) + 1 < sizeof(canonnamebuf)) {
135		strncpy(canonnamebuf, res->ai_canonname, sizeof(canonnamebuf));
136		*ahost = canonnamebuf;
137	}
138	nres = 0;
139	for (ai = res; ai; ai = ai->ai_next)
140		nres++;
141	ai = res;
142	refused = 0;
143	sigemptyset(&newmask);
144	sigaddset(&newmask, SIGURG);
145	__libc_sigprocmask(SIG_BLOCK, (const sigset_t *)&newmask, &oldmask);
146	for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
147		s = rresvport_af(&lport, ai->ai_family);
148		if (s < 0) {
149			if (errno != EAGAIN && ai->ai_next) {
150				ai = ai->ai_next;
151				continue;
152			}
153			if (errno == EAGAIN)
154				(void)fprintf(stderr,
155				    "rcmd: socket: All ports in use\n");
156			else
157				(void)fprintf(stderr, "rcmd: socket: %s\n",
158				    strerror(errno));
159			freeaddrinfo(res);
160			__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
161			    NULL);
162			return (-1);
163		}
164		_fcntl(s, F_SETOWN, pid);
165		if (_connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
166			break;
167		(void)_close(s);
168		if (errno == EADDRINUSE) {
169			lport--;
170			continue;
171		}
172		if (errno == ECONNREFUSED)
173			refused = 1;
174		if (ai->ai_next == NULL && (!refused || timo > 16)) {
175			(void)fprintf(stderr, "%s: %s\n",
176				      *ahost, strerror(errno));
177			freeaddrinfo(res);
178			__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
179			    NULL);
180			return (-1);
181		}
182		if (nres > 1) {
183			int oerrno = errno;
184
185			getnameinfo(ai->ai_addr, ai->ai_addrlen, paddr,
186			    sizeof(paddr), NULL, 0, NI_NUMERICHOST);
187			(void)fprintf(stderr, "connect to address %s: ",
188				      paddr);
189			errno = oerrno;
190			perror(0);
191		}
192		if ((ai = ai->ai_next) == NULL) {
193			/* refused && timo <= 16 */
194			struct timespec time_to_sleep, time_remaining;
195
196			time_to_sleep.tv_sec = timo;
197			time_to_sleep.tv_nsec = 0;
198			(void)_nanosleep(&time_to_sleep, &time_remaining);
199			timo *= 2;
200			ai = res;
201			refused = 0;
202		}
203		if (nres > 1) {
204			getnameinfo(ai->ai_addr, ai->ai_addrlen, paddr,
205			    sizeof(paddr), NULL, 0, NI_NUMERICHOST);
206			fprintf(stderr, "Trying %s...\n", paddr);
207		}
208	}
209	lport--;
210	if (fd2p == NULL) {
211		_write(s, "", 1);
212		lport = 0;
213	} else {
214		int s2 = rresvport_af(&lport, ai->ai_family), s3;
215		socklen_t len = ai->ai_addrlen;
216		int nfds;
217
218		if (s2 < 0)
219			goto bad;
220		_listen(s2, 1);
221		(void)snprintf(num, sizeof(num), "%d", lport);
222		if (_write(s, num, strlen(num)+1) != strlen(num)+1) {
223			(void)fprintf(stderr,
224			    "rcmd: write (setting up stderr): %s\n",
225			    strerror(errno));
226			(void)_close(s2);
227			goto bad;
228		}
229		nfds = max(s, s2)+1;
230		if(nfds > FD_SETSIZE) {
231			fprintf(stderr, "rcmd: too many files\n");
232			(void)_close(s2);
233			goto bad;
234		}
235again:
236		FD_ZERO(&reads);
237		FD_SET(s, &reads);
238		FD_SET(s2, &reads);
239		errno = 0;
240		if (_select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){
241			if (errno != 0)
242				(void)fprintf(stderr,
243				    "rcmd: select (setting up stderr): %s\n",
244				    strerror(errno));
245			else
246				(void)fprintf(stderr,
247				"select: protocol failure in circuit setup\n");
248			(void)_close(s2);
249			goto bad;
250		}
251		s3 = _accept(s2, (struct sockaddr *)&from, &len);
252		switch (from.ss_family) {
253		case AF_INET:
254			aport = ntohs(((struct sockaddr_in *)&from)->sin_port);
255			break;
256#ifdef INET6
257		case AF_INET6:
258			aport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
259			break;
260#endif
261		default:
262			aport = 0;	/* error */
263			break;
264		}
265		/*
266		 * XXX careful for ftp bounce attacks. If discovered, shut them
267		 * down and check for the real auxiliary channel to connect.
268		 */
269		if (aport == 20) {
270			_close(s3);
271			goto again;
272		}
273		(void)_close(s2);
274		if (s3 < 0) {
275			(void)fprintf(stderr,
276			    "rcmd: accept: %s\n", strerror(errno));
277			lport = 0;
278			goto bad;
279		}
280		*fd2p = s3;
281		if (aport >= IPPORT_RESERVED || aport < IPPORT_RESERVED / 2) {
282			(void)fprintf(stderr,
283			    "socket: protocol failure in circuit setup.\n");
284			goto bad2;
285		}
286	}
287	(void)_write(s, locuser, strlen(locuser)+1);
288	(void)_write(s, remuser, strlen(remuser)+1);
289	(void)_write(s, cmd, strlen(cmd)+1);
290	if (_read(s, &c, 1) != 1) {
291		(void)fprintf(stderr,
292		    "rcmd: %s: %s\n", *ahost, strerror(errno));
293		goto bad2;
294	}
295	if (c != 0) {
296		while (_read(s, &c, 1) == 1) {
297			(void)_write(STDERR_FILENO, &c, 1);
298			if (c == '\n')
299				break;
300		}
301		goto bad2;
302	}
303	__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
304	freeaddrinfo(res);
305	return (s);
306bad2:
307	if (lport)
308		(void)_close(*fd2p);
309bad:
310	(void)_close(s);
311	__libc_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
312	freeaddrinfo(res);
313	return (-1);
314}
315
316int
317rresvport(int *port)
318{
319	return rresvport_af(port, AF_INET);
320}
321
322int
323rresvport_af(int *alport, int family)
324{
325	int s;
326	struct sockaddr_storage ss;
327	u_short *sport;
328
329	memset(&ss, 0, sizeof(ss));
330	ss.ss_family = family;
331	switch (family) {
332	case AF_INET:
333		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in);
334		sport = &((struct sockaddr_in *)&ss)->sin_port;
335		((struct sockaddr_in *)&ss)->sin_addr.s_addr = INADDR_ANY;
336		break;
337#ifdef INET6
338	case AF_INET6:
339		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in6);
340		sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
341		((struct sockaddr_in6 *)&ss)->sin6_addr = in6addr_any;
342		break;
343#endif
344	default:
345		errno = EAFNOSUPPORT;
346		return -1;
347	}
348
349	s = _socket(ss.ss_family, SOCK_STREAM, 0);
350	if (s < 0)
351		return (-1);
352#if 0 /* compat_exact_traditional_rresvport_semantics */
353	sin.sin_port = htons((u_short)*alport);
354	if (_bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
355		return (s);
356	if (errno != EADDRINUSE) {
357		(void)_close(s);
358		return (-1);
359	}
360#endif
361	*sport = 0;
362	if (bindresvport_sa(s, (struct sockaddr *)&ss) == -1) {
363		(void)_close(s);
364		return (-1);
365	}
366	*alport = (int)ntohs(*sport);
367	return (s);
368}
369
370int	__check_rhosts_file = 1;
371char	*__rcmd_errstr;
372
373int
374ruserok(const char *rhost, int superuser, const char *ruser, const char *luser)
375{
376	struct addrinfo hints, *res, *r;
377	int error;
378
379	memset(&hints, 0, sizeof(hints));
380	hints.ai_family = PF_UNSPEC;
381	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
382	error = getaddrinfo(rhost, "0", &hints, &res);
383	if (error)
384		return (-1);
385
386	for (r = res; r; r = r->ai_next) {
387		if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
388		    luser) == 0) {
389			freeaddrinfo(res);
390			return (0);
391		}
392	}
393	freeaddrinfo(res);
394	return (-1);
395}
396
397/*
398 * New .rhosts strategy: We are passed an ip address. We spin through
399 * hosts.equiv and .rhosts looking for a match. When the .rhosts only
400 * has ip addresses, we don't have to trust a nameserver.  When it
401 * contains hostnames, we spin through the list of addresses the nameserver
402 * gives us and look for a match.
403 *
404 * Returns 0 if ok, -1 if not ok.
405 */
406int
407iruserok(unsigned long raddr, int superuser, const char *ruser, const char *luser)
408{
409	struct sockaddr_in sin;
410
411	memset(&sin, 0, sizeof(sin));
412	sin.sin_family = AF_INET;
413	sin.sin_len = sizeof(struct sockaddr_in);
414	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
415	return iruserok_sa((struct sockaddr *)&sin, sin.sin_len, superuser,
416		ruser, luser);
417}
418
419/*
420 * AF independent extension of iruserok.
421 *
422 * Returns 0 if ok, -1 if not ok.
423 */
424int
425iruserok_sa(const void *ra, int rlen, int superuser, const char *ruser,
426    const char *luser)
427{
428	char *cp;
429	struct stat sbuf;
430	struct passwd *pwd;
431	FILE *hostf;
432	uid_t uid;
433	int first;
434	char pbuf[MAXPATHLEN];
435	const struct sockaddr *raddr;
436	struct sockaddr_storage ss;
437
438	/* avoid alignment issue */
439	if (rlen > sizeof(ss))
440		return(-1);
441	memcpy(&ss, ra, rlen);
442	raddr = (struct sockaddr *)&ss;
443
444	first = 1;
445	hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "re");
446again:
447	if (hostf) {
448		if (__ivaliduser_sa(hostf, raddr, rlen, luser, ruser) == 0) {
449			(void)fclose(hostf);
450			return (0);
451		}
452		(void)fclose(hostf);
453	}
454	if (first == 1 && (__check_rhosts_file || superuser)) {
455		first = 0;
456		if ((pwd = getpwnam(luser)) == NULL)
457			return (-1);
458		(void)strcpy(pbuf, pwd->pw_dir);
459		(void)strcat(pbuf, "/.rhosts");
460
461		/*
462		 * Change effective uid while opening .rhosts.  If root and
463		 * reading an NFS mounted file system, can't read files that
464		 * are protected read/write owner only.
465		 */
466		uid = geteuid();
467		(void)seteuid(pwd->pw_uid);
468		hostf = fopen(pbuf, "re");
469		(void)seteuid(uid);
470
471		if (hostf == NULL)
472			return (-1);
473		/*
474		 * If not a regular file, or is owned by someone other than
475		 * user or root or if writeable by anyone but the owner, quit.
476		 */
477		cp = NULL;
478		if (lstat(pbuf, &sbuf) < 0)
479			cp = ".rhosts lstat failed";
480		else if (!S_ISREG(sbuf.st_mode))
481			cp = ".rhosts not regular file";
482		else if (_fstat(fileno(hostf), &sbuf) < 0)
483			cp = ".rhosts fstat failed";
484		else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
485			cp = "bad .rhosts owner";
486		else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
487			cp = ".rhosts writeable by other than owner";
488		/* If there were any problems, quit. */
489		if (cp) {
490			__rcmd_errstr = cp;
491			(void)fclose(hostf);
492			return (-1);
493		}
494		goto again;
495	}
496	return (-1);
497}
498
499/*
500 * XXX
501 * Don't make static, used by lpd(8).
502 *
503 * Returns 0 if ok, -1 if not ok.
504 */
505int
506__ivaliduser(FILE *hostf, u_int32_t raddr, const char *luser, const char *ruser)
507{
508	struct sockaddr_in sin;
509
510	memset(&sin, 0, sizeof(sin));
511	sin.sin_family = AF_INET;
512	sin.sin_len = sizeof(struct sockaddr_in);
513	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
514	return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
515		luser, ruser);
516}
517
518/*
519 * Returns 0 if ok, -1 if not ok.
520 *
521 * XXX obsolete API.
522 */
523int
524__ivaliduser_af(FILE *hostf, const void *raddr, const char *luser,
525    const char *ruser, int af, int len)
526{
527	struct sockaddr *sa = NULL;
528	struct sockaddr_in *sin = NULL;
529#ifdef INET6
530	struct sockaddr_in6 *sin6 = NULL;
531#endif
532	struct sockaddr_storage ss;
533
534	memset(&ss, 0, sizeof(ss));
535	switch (af) {
536	case AF_INET:
537		if (len != sizeof(sin->sin_addr))
538			return -1;
539		sin = (struct sockaddr_in *)&ss;
540		sin->sin_family = AF_INET;
541		sin->sin_len = sizeof(struct sockaddr_in);
542		memcpy(&sin->sin_addr, raddr, sizeof(sin->sin_addr));
543		break;
544#ifdef INET6
545	case AF_INET6:
546		if (len != sizeof(sin6->sin6_addr))
547			return -1;
548		/* you will lose scope info */
549		sin6 = (struct sockaddr_in6 *)&ss;
550		sin6->sin6_family = AF_INET6;
551		sin6->sin6_len = sizeof(struct sockaddr_in6);
552		memcpy(&sin6->sin6_addr, raddr, sizeof(sin6->sin6_addr));
553		break;
554#endif
555	default:
556		return -1;
557	}
558
559	sa = (struct sockaddr *)&ss;
560	return __ivaliduser_sa(hostf, sa, sa->sa_len, luser, ruser);
561}
562
563int
564__ivaliduser_sa(FILE *hostf, const struct sockaddr *raddr, socklen_t salen,
565    const char *luser, const char *ruser)
566{
567	char *user, *p;
568	int ch;
569	char buf[MAXHOSTNAMELEN + 128];		/* host + login */
570	char hname[MAXHOSTNAMELEN];
571	/* Presumed guilty until proven innocent. */
572	int userok = 0, hostok = 0;
573#ifdef YP
574	char *ypdomain;
575
576	if (yp_get_default_domain(&ypdomain))
577		ypdomain = NULL;
578#else
579#define	ypdomain NULL
580#endif
581	/* We need to get the damn hostname back for netgroup matching. */
582	if (getnameinfo(raddr, salen, hname, sizeof(hname), NULL, 0,
583			NI_NAMEREQD) != 0)
584		hname[0] = '\0';
585
586	while (fgets(buf, sizeof(buf), hostf)) {
587		p = buf;
588		/* Skip lines that are too long. */
589		if (strchr(p, '\n') == NULL) {
590			while ((ch = getc(hostf)) != '\n' && ch != EOF);
591			continue;
592		}
593		if (*p == '\n' || *p == '#') {
594			/* comment... */
595			continue;
596		}
597		while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
598			*p = isupper((unsigned char)*p) ? tolower((unsigned char)*p) : *p;
599			p++;
600		}
601		if (*p == ' ' || *p == '\t') {
602			*p++ = '\0';
603			while (*p == ' ' || *p == '\t')
604				p++;
605			user = p;
606			while (*p != '\n' && *p != ' ' &&
607			    *p != '\t' && *p != '\0')
608				p++;
609		} else
610			user = p;
611		*p = '\0';
612		/*
613		 * Do +/- and +@/-@ checking. This looks really nasty,
614		 * but it matches SunOS's behavior so far as I can tell.
615		 */
616		switch(buf[0]) {
617		case '+':
618			if (!buf[1]) {     /* '+' matches all hosts */
619				hostok = 1;
620				break;
621			}
622			if (buf[1] == '@')  /* match a host by netgroup */
623				hostok = hname[0] != '\0' &&
624				    innetgr(&buf[2], hname, NULL, ypdomain);
625			else		/* match a host by addr */
626				hostok = __icheckhost(raddr, salen,
627						      (char *)&buf[1]);
628			break;
629		case '-':     /* reject '-' hosts and all their users */
630			if (buf[1] == '@') {
631				if (hname[0] == '\0' ||
632				    innetgr(&buf[2], hname, NULL, ypdomain))
633					return(-1);
634			} else {
635				if (__icheckhost(raddr, salen,
636						 (char *)&buf[1]))
637					return(-1);
638			}
639			break;
640		default:  /* if no '+' or '-', do a simple match */
641			hostok = __icheckhost(raddr, salen, buf);
642			break;
643		}
644		switch(*user) {
645		case '+':
646			if (!*(user+1)) {      /* '+' matches all users */
647				userok = 1;
648				break;
649			}
650			if (*(user+1) == '@')  /* match a user by netgroup */
651				userok = innetgr(user+2, NULL, ruser, ypdomain);
652			else	   /* match a user by direct specification */
653				userok = !(strcmp(ruser, user+1));
654			break;
655		case '-': 		/* if we matched a hostname, */
656			if (hostok) {   /* check for user field rejections */
657				if (!*(user+1))
658					return(-1);
659				if (*(user+1) == '@') {
660					if (innetgr(user+2, NULL,
661							ruser, ypdomain))
662						return(-1);
663				} else {
664					if (!strcmp(ruser, user+1))
665						return(-1);
666				}
667			}
668			break;
669		default:	/* no rejections: try to match the user */
670			if (hostok)
671				userok = !(strcmp(ruser,*user ? user : luser));
672			break;
673		}
674		if (hostok && userok)
675			return(0);
676	}
677	return (-1);
678}
679
680/*
681 * Returns "true" if match, 0 if no match.
682 */
683static int
684__icheckhost(const struct sockaddr *raddr, socklen_t salen, const char *lhost)
685{
686	struct sockaddr_in sin;
687	struct sockaddr_in6 *sin6;
688	struct addrinfo hints, *res, *r;
689	int error;
690	char h1[NI_MAXHOST], h2[NI_MAXHOST];
691
692	if (raddr->sa_family == AF_INET6) {
693		sin6 = (struct sockaddr_in6 *)raddr;
694		if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
695			memset(&sin, 0, sizeof(sin));
696			sin.sin_family = AF_INET;
697			sin.sin_len = sizeof(struct sockaddr_in);
698			memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12],
699			       sizeof(sin.sin_addr));
700			raddr = (struct sockaddr *)&sin;
701			salen = sin.sin_len;
702		}
703	}
704
705	h1[0] = '\0';
706	if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
707			NI_NUMERICHOST) != 0)
708		return (0);
709
710	/* Resolve laddr into sockaddr */
711	memset(&hints, 0, sizeof(hints));
712	hints.ai_family = raddr->sa_family;
713	hints.ai_socktype = SOCK_DGRAM;	/*XXX dummy*/
714	res = NULL;
715	error = getaddrinfo(lhost, "0", &hints, &res);
716	if (error)
717		return (0);
718
719	for (r = res; r ; r = r->ai_next) {
720		h2[0] = '\0';
721		if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
722				NULL, 0, NI_NUMERICHOST) != 0)
723			continue;
724		if (strcmp(h1, h2) == 0) {
725			freeaddrinfo(res);
726			return (1);
727		}
728	}
729
730	/* No match. */
731	freeaddrinfo(res);
732	return (0);
733}
734