xref: /dragonfly/lib/libc/net/rcmd.c (revision 1de703da)
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  * 3. All advertising materials mentioning features or use of this software
14  *    must display the following acknowledgement:
15  *	This product includes software developed by the University of
16  *	California, Berkeley and its contributors.
17  * 4. Neither the name of the University nor the names of its contributors
18  *    may be used to endorse or promote products derived from this software
19  *    without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  *
33  * $FreeBSD: src/lib/libc/net/rcmd.c,v 1.23.2.7 2002/08/26 16:17:49 jdp Exp $
34  * $DragonFly: src/lib/libc/net/rcmd.c,v 1.2 2003/06/17 04:26:44 dillon Exp $
35  *
36  * @(#)rcmd.c	8.3 (Berkeley) 3/26/94
37  */
38 
39 #include <sys/param.h>
40 #include <sys/socket.h>
41 #include <sys/stat.h>
42 
43 #include <netinet/in.h>
44 #include <arpa/inet.h>
45 
46 #include <signal.h>
47 #include <fcntl.h>
48 #include <netdb.h>
49 #include <stdlib.h>
50 #include <unistd.h>
51 #include <pwd.h>
52 #include <errno.h>
53 #include <stdio.h>
54 #include <ctype.h>
55 #include <string.h>
56 #ifdef YP
57 #include <rpc/rpc.h>
58 #include <rpcsvc/yp_prot.h>
59 #include <rpcsvc/ypclnt.h>
60 #endif
61 #include <arpa/nameser.h>
62 
63 /* wrapper for KAME-special getnameinfo() */
64 #ifndef NI_WITHSCOPEID
65 #define NI_WITHSCOPEID	0
66 #endif
67 
68 extern int innetgr __P(( const char *, const char *, const char *, const char * ));
69 
70 #define max(a, b)	((a > b) ? a : b)
71 
72 int	__ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
73 int __ivaliduser_af __P((FILE *,const void *, const char *, const char *,
74 	int, int));
75 int __ivaliduser_sa __P((FILE *, const struct sockaddr *, socklen_t,
76 	const char *,const char *));
77 static int __icheckhost __P((const struct sockaddr *, socklen_t,
78 	const char *));
79 
80 char paddr[NI_MAXHOST];
81 
82 int
83 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
84 	char **ahost;
85 	u_short rport;
86 	const char *locuser, *remuser, *cmd;
87 	int *fd2p;
88 {
89 	return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
90 }
91 
92 int
93 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
94 	char **ahost;
95 	u_short rport;
96 	const char *locuser, *remuser, *cmd;
97 	int *fd2p;
98 	int af;
99 {
100 	struct addrinfo hints, *res, *ai;
101 	struct sockaddr_storage from;
102 	fd_set reads;
103 	long oldmask;
104 	pid_t pid;
105 	int s, aport, lport, timo, error;
106 	char c, *p;
107 	int refused, nres;
108 	char num[8];
109 	static char canonnamebuf[MAXDNAME];	/* is it proper here? */
110 
111 	/* call rcmdsh() with specified remote shell if appropriate. */
112 	if (!issetugid() && (p = getenv("RSH"))) {
113 		struct servent *sp = getservbyname("shell", "tcp");
114 
115 		if (sp && sp->s_port == rport)
116 			return (rcmdsh(ahost, rport, locuser, remuser,
117 			    cmd, p));
118 	}
119 
120 	/* use rsh(1) if non-root and remote port is shell. */
121 	if (geteuid()) {
122 		struct servent *sp = getservbyname("shell", "tcp");
123 
124 		if (sp && sp->s_port == rport)
125 			return (rcmdsh(ahost, rport, locuser, remuser,
126 			    cmd, NULL));
127 	}
128 
129 	pid = getpid();
130 
131 	memset(&hints, 0, sizeof(hints));
132 	hints.ai_flags = AI_CANONNAME;
133 	hints.ai_family = af;
134 	hints.ai_socktype = SOCK_STREAM;
135 	hints.ai_protocol = 0;
136 	(void)snprintf(num, sizeof(num), "%d", ntohs(rport));
137 	error = getaddrinfo(*ahost, num, &hints, &res);
138 	if (error) {
139 		fprintf(stderr, "rcmd: getaddrinfo: %s\n",
140 			gai_strerror(error));
141 		if (error == EAI_SYSTEM)
142 			fprintf(stderr, "rcmd: getaddrinfo: %s\n",
143 				strerror(errno));
144 		return (-1);
145 	}
146 
147 	if (res->ai_canonname
148 	 && strlen(res->ai_canonname) + 1 < sizeof(canonnamebuf)) {
149 		strncpy(canonnamebuf, res->ai_canonname, sizeof(canonnamebuf));
150 		*ahost = canonnamebuf;
151 	}
152 	nres = 0;
153 	for (ai = res; ai; ai = ai->ai_next)
154 		nres++;
155 	ai = res;
156 	refused = 0;
157 	oldmask = sigblock(sigmask(SIGURG));
158 	for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
159 		s = rresvport_af(&lport, ai->ai_family);
160 		if (s < 0) {
161 			if (errno != EAGAIN && ai->ai_next) {
162 				ai = ai->ai_next;
163 				continue;
164 			}
165 			if (errno == EAGAIN)
166 				(void)fprintf(stderr,
167 				    "rcmd: socket: All ports in use\n");
168 			else
169 				(void)fprintf(stderr, "rcmd: socket: %s\n",
170 				    strerror(errno));
171 			freeaddrinfo(res);
172 			sigsetmask(oldmask);
173 			return (-1);
174 		}
175 		_fcntl(s, F_SETOWN, pid);
176 		if (connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
177 			break;
178 		(void)_close(s);
179 		if (errno == EADDRINUSE) {
180 			lport--;
181 			continue;
182 		}
183 		if (errno == ECONNREFUSED)
184 			refused = 1;
185 		if (ai->ai_next == NULL && (!refused || timo > 16)) {
186 			(void)fprintf(stderr, "%s: %s\n",
187 				      *ahost, strerror(errno));
188 			freeaddrinfo(res);
189 			sigsetmask(oldmask);
190 			return (-1);
191 		}
192 		if (nres > 1) {
193 			int oerrno = errno;
194 
195 			getnameinfo(ai->ai_addr, ai->ai_addrlen,
196 				    paddr, sizeof(paddr),
197 				    NULL, 0,
198 				    NI_NUMERICHOST|NI_WITHSCOPEID);
199 			(void)fprintf(stderr, "connect to address %s: ",
200 				      paddr);
201 			errno = oerrno;
202 			perror(0);
203 		}
204 		if ((ai = ai->ai_next) == NULL) {
205 			/* refused && timo <= 16 */
206 			struct timespec time_to_sleep, time_remaining;
207 
208 			time_to_sleep.tv_sec = timo;
209 			time_to_sleep.tv_nsec = 0;
210 			(void)_nanosleep(&time_to_sleep, &time_remaining);
211 			timo *= 2;
212 			ai = res;
213 			refused = 0;
214 		}
215 		if (nres > 1) {
216 			getnameinfo(ai->ai_addr, ai->ai_addrlen,
217 				    paddr, sizeof(paddr),
218 				    NULL, 0,
219 				    NI_NUMERICHOST|NI_WITHSCOPEID);
220 			fprintf(stderr, "Trying %s...\n", paddr);
221 		}
222 	}
223 	lport--;
224 	if (fd2p == 0) {
225 		_write(s, "", 1);
226 		lport = 0;
227 	} else {
228 		char num[8];
229 		int s2 = rresvport_af(&lport, ai->ai_family), s3;
230 		int len = ai->ai_addrlen;
231 		int nfds;
232 
233 		if (s2 < 0)
234 			goto bad;
235 		listen(s2, 1);
236 		(void)snprintf(num, sizeof(num), "%d", lport);
237 		if (_write(s, num, strlen(num)+1) != strlen(num)+1) {
238 			(void)fprintf(stderr,
239 			    "rcmd: write (setting up stderr): %s\n",
240 			    strerror(errno));
241 			(void)_close(s2);
242 			goto bad;
243 		}
244 		nfds = max(s, s2)+1;
245 		if(nfds > FD_SETSIZE) {
246 			fprintf(stderr, "rcmd: too many files\n");
247 			(void)_close(s2);
248 			goto bad;
249 		}
250 again:
251 		FD_ZERO(&reads);
252 		FD_SET(s, &reads);
253 		FD_SET(s2, &reads);
254 		errno = 0;
255 		if (select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){
256 			if (errno != 0)
257 				(void)fprintf(stderr,
258 				    "rcmd: select (setting up stderr): %s\n",
259 				    strerror(errno));
260 			else
261 				(void)fprintf(stderr,
262 				"select: protocol failure in circuit setup\n");
263 			(void)_close(s2);
264 			goto bad;
265 		}
266 		s3 = accept(s2, (struct sockaddr *)&from, &len);
267 		switch (from.ss_family) {
268 		case AF_INET:
269 			aport = ntohs(((struct sockaddr_in *)&from)->sin_port);
270 			break;
271 #ifdef INET6
272 		case AF_INET6:
273 			aport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
274 			break;
275 #endif
276 		default:
277 			aport = 0;	/* error */
278 			break;
279 		}
280 		/*
281 		 * XXX careful for ftp bounce attacks. If discovered, shut them
282 		 * down and check for the real auxiliary channel to connect.
283 		 */
284 		if (aport == 20) {
285 			_close(s3);
286 			goto again;
287 		}
288 		(void)_close(s2);
289 		if (s3 < 0) {
290 			(void)fprintf(stderr,
291 			    "rcmd: accept: %s\n", strerror(errno));
292 			lport = 0;
293 			goto bad;
294 		}
295 		*fd2p = s3;
296 		if (aport >= IPPORT_RESERVED || aport < IPPORT_RESERVED / 2) {
297 			(void)fprintf(stderr,
298 			    "socket: protocol failure in circuit setup.\n");
299 			goto bad2;
300 		}
301 	}
302 	(void)_write(s, locuser, strlen(locuser)+1);
303 	(void)_write(s, remuser, strlen(remuser)+1);
304 	(void)_write(s, cmd, strlen(cmd)+1);
305 	if (_read(s, &c, 1) != 1) {
306 		(void)fprintf(stderr,
307 		    "rcmd: %s: %s\n", *ahost, strerror(errno));
308 		goto bad2;
309 	}
310 	if (c != 0) {
311 		while (_read(s, &c, 1) == 1) {
312 			(void)_write(STDERR_FILENO, &c, 1);
313 			if (c == '\n')
314 				break;
315 		}
316 		goto bad2;
317 	}
318 	sigsetmask(oldmask);
319 	freeaddrinfo(res);
320 	return (s);
321 bad2:
322 	if (lport)
323 		(void)_close(*fd2p);
324 bad:
325 	(void)_close(s);
326 	sigsetmask(oldmask);
327 	freeaddrinfo(res);
328 	return (-1);
329 }
330 
331 int
332 rresvport(port)
333 	int *port;
334 {
335 	return rresvport_af(port, AF_INET);
336 }
337 
338 int
339 rresvport_af(alport, family)
340 	int *alport, family;
341 {
342 	int i, s, len, err;
343 	struct sockaddr_storage ss;
344 	u_short *sport;
345 
346 	memset(&ss, 0, sizeof(ss));
347 	ss.ss_family = family;
348 	switch (family) {
349 	case AF_INET:
350 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in);
351 		sport = &((struct sockaddr_in *)&ss)->sin_port;
352 		((struct sockaddr_in *)&ss)->sin_addr.s_addr = INADDR_ANY;
353 		break;
354 #ifdef INET6
355 	case AF_INET6:
356 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in6);
357 		sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
358 		((struct sockaddr_in6 *)&ss)->sin6_addr = in6addr_any;
359 		break;
360 #endif
361 	default:
362 		errno = EAFNOSUPPORT;
363 		return -1;
364 	}
365 
366 	s = socket(ss.ss_family, SOCK_STREAM, 0);
367 	if (s < 0)
368 		return (-1);
369 #if 0 /* compat_exact_traditional_rresvport_semantics */
370 	sin.sin_port = htons((u_short)*alport);
371 	if (bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
372 		return (s);
373 	if (errno != EADDRINUSE) {
374 		(void)_close(s);
375 		return (-1);
376 	}
377 #endif
378 	*sport = 0;
379 	if (bindresvport_sa(s, (struct sockaddr *)&ss) == -1) {
380 		(void)_close(s);
381 		return (-1);
382 	}
383 	*alport = (int)ntohs(*sport);
384 	return (s);
385 }
386 
387 int	__check_rhosts_file = 1;
388 char	*__rcmd_errstr;
389 
390 int
391 ruserok(rhost, superuser, ruser, luser)
392 	const char *rhost, *ruser, *luser;
393 	int superuser;
394 {
395 	struct addrinfo hints, *res, *r;
396 	int error;
397 
398 	memset(&hints, 0, sizeof(hints));
399 	hints.ai_family = PF_UNSPEC;
400 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
401 	error = getaddrinfo(rhost, "0", &hints, &res);
402 	if (error)
403 		return (-1);
404 
405 	for (r = res; r; r = r->ai_next) {
406 		if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
407 		    luser) == 0) {
408 			freeaddrinfo(res);
409 			return (0);
410 		}
411 	}
412 	freeaddrinfo(res);
413 	return (-1);
414 }
415 
416 /*
417  * New .rhosts strategy: We are passed an ip address. We spin through
418  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
419  * has ip addresses, we don't have to trust a nameserver.  When it
420  * contains hostnames, we spin through the list of addresses the nameserver
421  * gives us and look for a match.
422  *
423  * Returns 0 if ok, -1 if not ok.
424  */
425 int
426 iruserok(raddr, superuser, ruser, luser)
427 	unsigned long raddr;
428 	int superuser;
429 	const char *ruser, *luser;
430 {
431 	struct sockaddr_in sin;
432 
433 	memset(&sin, 0, sizeof(sin));
434 	sin.sin_family = AF_INET;
435 	sin.sin_len = sizeof(struct sockaddr_in);
436 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
437 	return iruserok_sa((struct sockaddr *)&sin, sin.sin_len, superuser,
438 		ruser, luser);
439 }
440 
441 /*
442  * AF independent extension of iruserok.
443  *
444  * Returns 0 if ok, -1 if not ok.
445  */
446 int
447 iruserok_sa(ra, rlen, superuser, ruser, luser)
448 	const void *ra;
449 	int rlen;
450 	int superuser;
451 	const char *ruser, *luser;
452 {
453 	register char *cp;
454 	struct stat sbuf;
455 	struct passwd *pwd;
456 	FILE *hostf;
457 	uid_t uid;
458 	int first;
459 	char pbuf[MAXPATHLEN];
460 	const struct sockaddr *raddr;
461 	struct sockaddr_storage ss;
462 
463 	/* avoid alignment issue */
464 	if (rlen > sizeof(ss))
465 		return(-1);
466 	memcpy(&ss, ra, rlen);
467 	raddr = (struct sockaddr *)&ss;
468 
469 	first = 1;
470 	hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
471 again:
472 	if (hostf) {
473 		if (__ivaliduser_sa(hostf, raddr, rlen, luser, ruser) == 0) {
474 			(void)fclose(hostf);
475 			return (0);
476 		}
477 		(void)fclose(hostf);
478 	}
479 	if (first == 1 && (__check_rhosts_file || superuser)) {
480 		first = 0;
481 		if ((pwd = getpwnam(luser)) == NULL)
482 			return (-1);
483 		(void)strcpy(pbuf, pwd->pw_dir);
484 		(void)strcat(pbuf, "/.rhosts");
485 
486 		/*
487 		 * Change effective uid while opening .rhosts.  If root and
488 		 * reading an NFS mounted file system, can't read files that
489 		 * are protected read/write owner only.
490 		 */
491 		uid = geteuid();
492 		(void)seteuid(pwd->pw_uid);
493 		hostf = fopen(pbuf, "r");
494 		(void)seteuid(uid);
495 
496 		if (hostf == NULL)
497 			return (-1);
498 		/*
499 		 * If not a regular file, or is owned by someone other than
500 		 * user or root or if writeable by anyone but the owner, quit.
501 		 */
502 		cp = NULL;
503 		if (lstat(pbuf, &sbuf) < 0)
504 			cp = ".rhosts lstat failed";
505 		else if (!S_ISREG(sbuf.st_mode))
506 			cp = ".rhosts not regular file";
507 		else if (fstat(fileno(hostf), &sbuf) < 0)
508 			cp = ".rhosts fstat failed";
509 		else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
510 			cp = "bad .rhosts owner";
511 		else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
512 			cp = ".rhosts writeable by other than owner";
513 		/* If there were any problems, quit. */
514 		if (cp) {
515 			__rcmd_errstr = cp;
516 			(void)fclose(hostf);
517 			return (-1);
518 		}
519 		goto again;
520 	}
521 	return (-1);
522 }
523 
524 /*
525  * XXX
526  * Don't make static, used by lpd(8).
527  *
528  * Returns 0 if ok, -1 if not ok.
529  */
530 int
531 __ivaliduser(hostf, raddr, luser, ruser)
532 	FILE *hostf;
533 	u_int32_t raddr;
534 	const char *luser, *ruser;
535 {
536 	struct sockaddr_in sin;
537 
538 	memset(&sin, 0, sizeof(sin));
539 	sin.sin_family = AF_INET;
540 	sin.sin_len = sizeof(struct sockaddr_in);
541 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
542 	return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
543 		luser, ruser);
544 }
545 
546 /*
547  * Returns 0 if ok, -1 if not ok.
548  *
549  * XXX obsolete API.
550  */
551 int
552 __ivaliduser_af(hostf, raddr, luser, ruser, af, len)
553 	FILE *hostf;
554 	const void *raddr;
555 	const char *luser, *ruser;
556 	int af, len;
557 {
558 	struct sockaddr *sa = NULL;
559 	struct sockaddr_in *sin = NULL;
560 #ifdef INET6
561 	struct sockaddr_in6 *sin6 = NULL;
562 #endif
563 	struct sockaddr_storage ss;
564 
565 	memset(&ss, 0, sizeof(ss));
566 	switch (af) {
567 	case AF_INET:
568 		if (len != sizeof(sin->sin_addr))
569 			return -1;
570 		sin = (struct sockaddr_in *)&ss;
571 		sin->sin_family = AF_INET;
572 		sin->sin_len = sizeof(struct sockaddr_in);
573 		memcpy(&sin->sin_addr, raddr, sizeof(sin->sin_addr));
574 		break;
575 #ifdef INET6
576 	case AF_INET6:
577 		if (len != sizeof(sin6->sin6_addr))
578 			return -1;
579 		/* you will lose scope info */
580 		sin6 = (struct sockaddr_in6 *)&ss;
581 		sin6->sin6_family = AF_INET6;
582 		sin6->sin6_len = sizeof(struct sockaddr_in6);
583 		memcpy(&sin6->sin6_addr, raddr, sizeof(sin6->sin6_addr));
584 		break;
585 #endif
586 	default:
587 		return -1;
588 	}
589 
590 	sa = (struct sockaddr *)&ss;
591 	return __ivaliduser_sa(hostf, sa, sa->sa_len, luser, ruser);
592 }
593 
594 /*
595  * Returns 0 if ok, -1 if not ok.
596  */
597 int
598 __ivaliduser_sa(hostf, raddr, salen, luser, ruser)
599 	FILE *hostf;
600 	const struct sockaddr *raddr;
601 	socklen_t salen;
602 	const char *luser, *ruser;
603 {
604 	register char *user, *p;
605 	int ch;
606 	char buf[MAXHOSTNAMELEN + 128];		/* host + login */
607 	char hname[MAXHOSTNAMELEN];
608 	/* Presumed guilty until proven innocent. */
609 	int userok = 0, hostok = 0;
610 	int h_error;
611 #ifdef YP
612 	char *ypdomain;
613 
614 	if (yp_get_default_domain(&ypdomain))
615 		ypdomain = NULL;
616 #else
617 #define	ypdomain NULL
618 #endif
619 	/* We need to get the damn hostname back for netgroup matching. */
620 	if (getnameinfo(raddr, salen, hname, sizeof(hname), NULL, 0,
621 			NI_NAMEREQD) != 0)
622 		hname[0] = '\0';
623 
624 	while (fgets(buf, sizeof(buf), hostf)) {
625 		p = buf;
626 		/* Skip lines that are too long. */
627 		if (strchr(p, '\n') == NULL) {
628 			while ((ch = getc(hostf)) != '\n' && ch != EOF);
629 			continue;
630 		}
631 		if (*p == '\n' || *p == '#') {
632 			/* comment... */
633 			continue;
634 		}
635 		while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
636 			*p = isupper((unsigned char)*p) ? tolower((unsigned char)*p) : *p;
637 			p++;
638 		}
639 		if (*p == ' ' || *p == '\t') {
640 			*p++ = '\0';
641 			while (*p == ' ' || *p == '\t')
642 				p++;
643 			user = p;
644 			while (*p != '\n' && *p != ' ' &&
645 			    *p != '\t' && *p != '\0')
646 				p++;
647 		} else
648 			user = p;
649 		*p = '\0';
650 		/*
651 		 * Do +/- and +@/-@ checking. This looks really nasty,
652 		 * but it matches SunOS's behavior so far as I can tell.
653 		 */
654 		switch(buf[0]) {
655 		case '+':
656 			if (!buf[1]) {     /* '+' matches all hosts */
657 				hostok = 1;
658 				break;
659 			}
660 			if (buf[1] == '@')  /* match a host by netgroup */
661 				hostok = hname[0] != '\0' &&
662 				    innetgr(&buf[2], hname, NULL, ypdomain);
663 			else		/* match a host by addr */
664 				hostok = __icheckhost(raddr, salen,
665 						      (char *)&buf[1]);
666 			break;
667 		case '-':     /* reject '-' hosts and all their users */
668 			if (buf[1] == '@') {
669 				if (hname[0] == '\0' ||
670 				    innetgr(&buf[2], hname, NULL, ypdomain))
671 					return(-1);
672 			} else {
673 				if (__icheckhost(raddr, salen,
674 						 (char *)&buf[1]))
675 					return(-1);
676 			}
677 			break;
678 		default:  /* if no '+' or '-', do a simple match */
679 			hostok = __icheckhost(raddr, salen, buf);
680 			break;
681 		}
682 		switch(*user) {
683 		case '+':
684 			if (!*(user+1)) {      /* '+' matches all users */
685 				userok = 1;
686 				break;
687 			}
688 			if (*(user+1) == '@')  /* match a user by netgroup */
689 				userok = innetgr(user+2, NULL, ruser, ypdomain);
690 			else	   /* match a user by direct specification */
691 				userok = !(strcmp(ruser, user+1));
692 			break;
693 		case '-': 		/* if we matched a hostname, */
694 			if (hostok) {   /* check for user field rejections */
695 				if (!*(user+1))
696 					return(-1);
697 				if (*(user+1) == '@') {
698 					if (innetgr(user+2, NULL,
699 							ruser, ypdomain))
700 						return(-1);
701 				} else {
702 					if (!strcmp(ruser, user+1))
703 						return(-1);
704 				}
705 			}
706 			break;
707 		default:	/* no rejections: try to match the user */
708 			if (hostok)
709 				userok = !(strcmp(ruser,*user ? user : luser));
710 			break;
711 		}
712 		if (hostok && userok)
713 			return(0);
714 	}
715 	return (-1);
716 }
717 
718 /*
719  * Returns "true" if match, 0 if no match.
720  *
721  * NI_WITHSCOPEID is useful for comparing sin6_scope_id portion
722  * if af == AF_INET6.
723  */
724 static int
725 __icheckhost(raddr, salen, lhost)
726 	const struct sockaddr *raddr;
727 	socklen_t salen;
728         const char *lhost;
729 {
730 	struct sockaddr_in sin;
731 	struct sockaddr_in6 *sin6;
732 	struct addrinfo hints, *res, *r;
733 	int error;
734 	char h1[NI_MAXHOST], h2[NI_MAXHOST];
735 
736 	if (raddr->sa_family == AF_INET6) {
737 		sin6 = (struct sockaddr_in6 *)raddr;
738 		if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
739 			memset(&sin, 0, sizeof(sin));
740 			sin.sin_family = AF_INET;
741 			sin.sin_len = sizeof(struct sockaddr_in);
742 			memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12],
743 			       sizeof(sin.sin_addr));
744 			raddr = (struct sockaddr *)&sin;
745 			salen = sin.sin_len;
746 		}
747 	}
748 
749 	h1[0] = '\0';
750 	if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
751 			NI_NUMERICHOST | NI_WITHSCOPEID) != 0)
752 		return (0);
753 
754 	/* Resolve laddr into sockaddr */
755 	memset(&hints, 0, sizeof(hints));
756 	hints.ai_family = raddr->sa_family;
757 	hints.ai_socktype = SOCK_DGRAM;	/*XXX dummy*/
758 	res = NULL;
759 	error = getaddrinfo(lhost, "0", &hints, &res);
760 	if (error)
761 		return (0);
762 
763 	for (r = res; r ; r = r->ai_next) {
764 		h2[0] = '\0';
765 		if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
766 				NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID) != 0)
767 			continue;
768 		if (strcmp(h1, h2) == 0) {
769 			freeaddrinfo(res);
770 			return (1);
771 		}
772 	}
773 
774 	/* No match. */
775 	freeaddrinfo(res);
776 	return (0);
777 }
778