xref: /freebsd/lib/libc/net/rcmd.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c)
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  * $FreeBSD$
34  */
35 
36 #if defined(LIBC_SCCS) && !defined(lint)
37 static char sccsid[] = "@(#)rcmd.c	8.3 (Berkeley) 3/26/94";
38 #endif /* LIBC_SCCS and not lint */
39 
40 #include "namespace.h"
41 #include <sys/param.h>
42 #include <sys/socket.h>
43 #include <sys/stat.h>
44 
45 #include <netinet/in.h>
46 #include <arpa/inet.h>
47 
48 #include <signal.h>
49 #include <fcntl.h>
50 #include <netdb.h>
51 #include <unistd.h>
52 #include <pwd.h>
53 #include <errno.h>
54 #include <stdio.h>
55 #include <ctype.h>
56 #include <string.h>
57 #ifdef YP
58 #include <rpc/rpc.h>
59 #include <rpcsvc/yp_prot.h>
60 #include <rpcsvc/ypclnt.h>
61 #endif
62 #include <arpa/nameser.h>
63 #include "un-namespace.h"
64 
65 /* wrapper for KAME-special getnameinfo() */
66 #ifndef NI_WITHSCOPEID
67 #define NI_WITHSCOPEID	0
68 #endif
69 
70 extern int innetgr __P(( const char *, const char *, const char *, const char * ));
71 
72 #define max(a, b)	((a > b) ? a : b)
73 
74 int	__ivaliduser __P((FILE *, u_int32_t, const char *, const char *));
75 int __ivaliduser_af __P((FILE *,const void *, const char *, const char *,
76 	int, int));
77 int __ivaliduser_sa __P((FILE *, const struct sockaddr *, socklen_t,
78 	const char *,const char *));
79 static int __icheckhost __P((const struct sockaddr *, socklen_t,
80 	const char *));
81 
82 char paddr[NI_MAXHOST];
83 
84 int
85 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
86 	char **ahost;
87 	u_short rport;
88 	const char *locuser, *remuser, *cmd;
89 	int *fd2p;
90 {
91 	return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
92 }
93 
94 int
95 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
96 	char **ahost;
97 	u_short rport;
98 	const char *locuser, *remuser, *cmd;
99 	int *fd2p;
100 	int af;
101 {
102 	struct addrinfo hints, *res, *ai;
103 	struct sockaddr_storage from;
104 	fd_set reads;
105 	sigset_t oldmask, newmask;
106 	pid_t pid;
107 	int s, aport, lport, timo, error;
108 	char c;
109 	int refused, nres;
110 	char num[8];
111 	static char canonnamebuf[MAXDNAME];	/* is it proper here? */
112 
113 	pid = getpid();
114 
115 	memset(&hints, 0, sizeof(hints));
116 	hints.ai_flags = AI_CANONNAME;
117 	hints.ai_family = af;
118 	hints.ai_socktype = SOCK_STREAM;
119 	hints.ai_protocol = 0;
120 	(void)snprintf(num, sizeof(num), "%d", ntohs(rport));
121 	error = getaddrinfo(*ahost, num, &hints, &res);
122 	if (error) {
123 		fprintf(stderr, "rcmd: getaddrinfo: %s\n",
124 			gai_strerror(error));
125 		if (error == EAI_SYSTEM)
126 			fprintf(stderr, "rcmd: getaddrinfo: %s\n",
127 				strerror(errno));
128 		return (-1);
129 	}
130 
131 	if (res->ai_canonname
132 	 && strlen(res->ai_canonname) + 1 < sizeof(canonnamebuf)) {
133 		strncpy(canonnamebuf, res->ai_canonname, sizeof(canonnamebuf));
134 		*ahost = canonnamebuf;
135 	}
136 	nres = 0;
137 	for (ai = res; ai; ai = ai->ai_next)
138 		nres++;
139 	ai = res;
140 	refused = 0;
141 	sigemptyset(&newmask);
142 	sigaddset(&newmask, SIGURG);
143 	_sigprocmask(SIG_BLOCK, (const sigset_t *)&newmask, &oldmask);
144 	for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
145 		s = rresvport_af(&lport, ai->ai_family);
146 		if (s < 0) {
147 			if (errno != EAGAIN && ai->ai_next) {
148 				ai = ai->ai_next;
149 				continue;
150 			}
151 			if (errno == EAGAIN)
152 				(void)fprintf(stderr,
153 				    "rcmd: socket: All ports in use\n");
154 			else
155 				(void)fprintf(stderr, "rcmd: socket: %s\n",
156 				    strerror(errno));
157 			freeaddrinfo(res);
158 			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
159 			    NULL);
160 			return (-1);
161 		}
162 		_fcntl(s, F_SETOWN, pid);
163 		if (_connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
164 			break;
165 		(void)_close(s);
166 		if (errno == EADDRINUSE) {
167 			lport--;
168 			continue;
169 		}
170 		if (errno == ECONNREFUSED)
171 			refused = 1;
172 		if (ai->ai_next == NULL && (!refused || timo > 16)) {
173 			(void)fprintf(stderr, "%s: %s\n",
174 				      *ahost, strerror(errno));
175 			freeaddrinfo(res);
176 			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
177 			    NULL);
178 			return (-1);
179 		}
180 		if (nres > 1) {
181 			int oerrno = errno;
182 
183 			getnameinfo(ai->ai_addr, ai->ai_addrlen,
184 				    paddr, sizeof(paddr),
185 				    NULL, 0,
186 				    NI_NUMERICHOST|NI_WITHSCOPEID);
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,
205 				    paddr, sizeof(paddr),
206 				    NULL, 0,
207 				    NI_NUMERICHOST|NI_WITHSCOPEID);
208 			fprintf(stderr, "Trying %s...\n", paddr);
209 		}
210 	}
211 	lport--;
212 	if (fd2p == 0) {
213 		_write(s, "", 1);
214 		lport = 0;
215 	} else {
216 		char num[8];
217 		int s2 = rresvport_af(&lport, ai->ai_family), s3;
218 		int len = ai->ai_addrlen;
219 		int nfds;
220 
221 		if (s2 < 0)
222 			goto bad;
223 		_listen(s2, 1);
224 		(void)snprintf(num, sizeof(num), "%d", lport);
225 		if (_write(s, num, strlen(num)+1) != strlen(num)+1) {
226 			(void)fprintf(stderr,
227 			    "rcmd: write (setting up stderr): %s\n",
228 			    strerror(errno));
229 			(void)_close(s2);
230 			goto bad;
231 		}
232 		nfds = max(s, s2)+1;
233 		if(nfds > FD_SETSIZE) {
234 			fprintf(stderr, "rcmd: too many files\n");
235 			(void)_close(s2);
236 			goto bad;
237 		}
238 again:
239 		FD_ZERO(&reads);
240 		FD_SET(s, &reads);
241 		FD_SET(s2, &reads);
242 		errno = 0;
243 		if (_select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){
244 			if (errno != 0)
245 				(void)fprintf(stderr,
246 				    "rcmd: select (setting up stderr): %s\n",
247 				    strerror(errno));
248 			else
249 				(void)fprintf(stderr,
250 				"select: protocol failure in circuit setup\n");
251 			(void)_close(s2);
252 			goto bad;
253 		}
254 		s3 = _accept(s2, (struct sockaddr *)&from, &len);
255 		switch (from.ss_family) {
256 		case AF_INET:
257 			aport = ntohs(((struct sockaddr_in *)&from)->sin_port);
258 			break;
259 #ifdef INET6
260 		case AF_INET6:
261 			aport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
262 			break;
263 #endif
264 		default:
265 			aport = 0;	/* error */
266 			break;
267 		}
268 		/*
269 		 * XXX careful for ftp bounce attacks. If discovered, shut them
270 		 * down and check for the real auxiliary channel to connect.
271 		 */
272 		if (aport == 20) {
273 			_close(s3);
274 			goto again;
275 		}
276 		(void)_close(s2);
277 		if (s3 < 0) {
278 			(void)fprintf(stderr,
279 			    "rcmd: accept: %s\n", strerror(errno));
280 			lport = 0;
281 			goto bad;
282 		}
283 		*fd2p = s3;
284 		if (aport >= IPPORT_RESERVED || aport < IPPORT_RESERVED / 2) {
285 			(void)fprintf(stderr,
286 			    "socket: protocol failure in circuit setup.\n");
287 			goto bad2;
288 		}
289 	}
290 	(void)_write(s, locuser, strlen(locuser)+1);
291 	(void)_write(s, remuser, strlen(remuser)+1);
292 	(void)_write(s, cmd, strlen(cmd)+1);
293 	if (_read(s, &c, 1) != 1) {
294 		(void)fprintf(stderr,
295 		    "rcmd: %s: %s\n", *ahost, strerror(errno));
296 		goto bad2;
297 	}
298 	if (c != 0) {
299 		while (_read(s, &c, 1) == 1) {
300 			(void)_write(STDERR_FILENO, &c, 1);
301 			if (c == '\n')
302 				break;
303 		}
304 		goto bad2;
305 	}
306 	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
307 	freeaddrinfo(res);
308 	return (s);
309 bad2:
310 	if (lport)
311 		(void)_close(*fd2p);
312 bad:
313 	(void)_close(s);
314 	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
315 	freeaddrinfo(res);
316 	return (-1);
317 }
318 
319 int
320 rresvport(port)
321 	int *port;
322 {
323 	return rresvport_af(port, AF_INET);
324 }
325 
326 int
327 rresvport_af(alport, family)
328 	int *alport, family;
329 {
330 	int i, s, len, err;
331 	struct sockaddr_storage ss;
332 	u_short *sport;
333 
334 	memset(&ss, 0, sizeof(ss));
335 	ss.ss_family = family;
336 	switch (family) {
337 	case AF_INET:
338 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in);
339 		sport = &((struct sockaddr_in *)&ss)->sin_port;
340 		((struct sockaddr_in *)&ss)->sin_addr.s_addr = INADDR_ANY;
341 		break;
342 #ifdef INET6
343 	case AF_INET6:
344 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in6);
345 		sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
346 		((struct sockaddr_in6 *)&ss)->sin6_addr = in6addr_any;
347 		break;
348 #endif
349 	default:
350 		errno = EAFNOSUPPORT;
351 		return -1;
352 	}
353 
354 	s = _socket(ss.ss_family, SOCK_STREAM, 0);
355 	if (s < 0)
356 		return (-1);
357 #if 0 /* compat_exact_traditional_rresvport_semantics */
358 	sin.sin_port = htons((u_short)*alport);
359 	if (_bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
360 		return (s);
361 	if (errno != EADDRINUSE) {
362 		(void)_close(s);
363 		return (-1);
364 	}
365 #endif
366 	*sport = 0;
367 	if (bindresvport_sa(s, (struct sockaddr *)&ss) == -1) {
368 		(void)_close(s);
369 		return (-1);
370 	}
371 	*alport = (int)ntohs(*sport);
372 	return (s);
373 }
374 
375 int	__check_rhosts_file = 1;
376 char	*__rcmd_errstr;
377 
378 int
379 ruserok(rhost, superuser, ruser, luser)
380 	const char *rhost, *ruser, *luser;
381 	int superuser;
382 {
383 	struct addrinfo hints, *res, *r;
384 	int error;
385 
386 	memset(&hints, 0, sizeof(hints));
387 	hints.ai_family = PF_UNSPEC;
388 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
389 	error = getaddrinfo(rhost, "0", &hints, &res);
390 	if (error)
391 		return (-1);
392 
393 	for (r = res; r; r = r->ai_next) {
394 		if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
395 		    luser) == 0) {
396 			freeaddrinfo(res);
397 			return (0);
398 		}
399 	}
400 	freeaddrinfo(res);
401 	return (-1);
402 }
403 
404 /*
405  * New .rhosts strategy: We are passed an ip address. We spin through
406  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
407  * has ip addresses, we don't have to trust a nameserver.  When it
408  * contains hostnames, we spin through the list of addresses the nameserver
409  * gives us and look for a match.
410  *
411  * Returns 0 if ok, -1 if not ok.
412  */
413 int
414 iruserok(raddr, superuser, ruser, luser)
415 	unsigned long raddr;
416 	int superuser;
417 	const char *ruser, *luser;
418 {
419 	struct sockaddr_in sin;
420 
421 	memset(&sin, 0, sizeof(sin));
422 	sin.sin_family = AF_INET;
423 	sin.sin_len = sizeof(struct sockaddr_in);
424 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
425 	return iruserok_sa((struct sockaddr *)&sin, sin.sin_len, superuser,
426 		ruser, luser);
427 }
428 
429 /*
430  * AF independent extension of iruserok.
431  *
432  * Returns 0 if ok, -1 if not ok.
433  */
434 int
435 iruserok_sa(ra, rlen, superuser, ruser, luser)
436 	const void *ra;
437 	int rlen;
438 	int superuser;
439 	const char *ruser, *luser;
440 {
441 	register char *cp;
442 	struct stat sbuf;
443 	struct passwd *pwd;
444 	FILE *hostf;
445 	uid_t uid;
446 	int first;
447 	char pbuf[MAXPATHLEN];
448 	const struct sockaddr *raddr;
449 	struct sockaddr_storage ss;
450 
451 	/* avoid alignment issue */
452 	if (rlen > sizeof(ss))
453 		return(-1);
454 	memcpy(&ss, ra, rlen);
455 	raddr = (struct sockaddr *)&ss;
456 
457 	first = 1;
458 	hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
459 again:
460 	if (hostf) {
461 		if (__ivaliduser_sa(hostf, raddr, rlen, luser, ruser) == 0) {
462 			(void)fclose(hostf);
463 			return (0);
464 		}
465 		(void)fclose(hostf);
466 	}
467 	if (first == 1 && (__check_rhosts_file || superuser)) {
468 		first = 0;
469 		if ((pwd = getpwnam(luser)) == NULL)
470 			return (-1);
471 		(void)strcpy(pbuf, pwd->pw_dir);
472 		(void)strcat(pbuf, "/.rhosts");
473 
474 		/*
475 		 * Change effective uid while opening .rhosts.  If root and
476 		 * reading an NFS mounted file system, can't read files that
477 		 * are protected read/write owner only.
478 		 */
479 		uid = geteuid();
480 		(void)seteuid(pwd->pw_uid);
481 		hostf = fopen(pbuf, "r");
482 		(void)seteuid(uid);
483 
484 		if (hostf == NULL)
485 			return (-1);
486 		/*
487 		 * If not a regular file, or is owned by someone other than
488 		 * user or root or if writeable by anyone but the owner, quit.
489 		 */
490 		cp = NULL;
491 		if (lstat(pbuf, &sbuf) < 0)
492 			cp = ".rhosts lstat failed";
493 		else if (!S_ISREG(sbuf.st_mode))
494 			cp = ".rhosts not regular file";
495 		else if (_fstat(fileno(hostf), &sbuf) < 0)
496 			cp = ".rhosts fstat failed";
497 		else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
498 			cp = "bad .rhosts owner";
499 		else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
500 			cp = ".rhosts writeable by other than owner";
501 		/* If there were any problems, quit. */
502 		if (cp) {
503 			__rcmd_errstr = cp;
504 			(void)fclose(hostf);
505 			return (-1);
506 		}
507 		goto again;
508 	}
509 	return (-1);
510 }
511 
512 /*
513  * XXX
514  * Don't make static, used by lpd(8).
515  *
516  * Returns 0 if ok, -1 if not ok.
517  */
518 int
519 __ivaliduser(hostf, raddr, luser, ruser)
520 	FILE *hostf;
521 	u_int32_t raddr;
522 	const char *luser, *ruser;
523 {
524 	struct sockaddr_in sin;
525 
526 	memset(&sin, 0, sizeof(sin));
527 	sin.sin_family = AF_INET;
528 	sin.sin_len = sizeof(struct sockaddr_in);
529 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
530 	return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
531 		luser, ruser);
532 }
533 
534 /*
535  * Returns 0 if ok, -1 if not ok.
536  *
537  * XXX obsolete API.
538  */
539 int
540 __ivaliduser_af(hostf, raddr, luser, ruser, af, len)
541 	FILE *hostf;
542 	const void *raddr;
543 	const char *luser, *ruser;
544 	int af, len;
545 {
546 	struct sockaddr *sa = NULL;
547 	struct sockaddr_in *sin = NULL;
548 #ifdef INET6
549 	struct sockaddr_in6 *sin6 = NULL;
550 #endif
551 	struct sockaddr_storage ss;
552 
553 	memset(&ss, 0, sizeof(ss));
554 	switch (af) {
555 	case AF_INET:
556 		if (len != sizeof(sin->sin_addr))
557 			return -1;
558 		sin = (struct sockaddr_in *)&ss;
559 		sin->sin_family = AF_INET;
560 		sin->sin_len = sizeof(struct sockaddr_in);
561 		memcpy(&sin->sin_addr, raddr, sizeof(sin->sin_addr));
562 		break;
563 #ifdef INET6
564 	case AF_INET6:
565 		if (len != sizeof(sin6->sin6_addr))
566 			return -1;
567 		/* you will lose scope info */
568 		sin6 = (struct sockaddr_in6 *)&ss;
569 		sin6->sin6_family = AF_INET6;
570 		sin6->sin6_len = sizeof(struct sockaddr_in6);
571 		memcpy(&sin6->sin6_addr, raddr, sizeof(sin6->sin6_addr));
572 		break;
573 #endif
574 	default:
575 		return -1;
576 	}
577 
578 	sa = (struct sockaddr *)&ss;
579 	return __ivaliduser_sa(hostf, sa, sa->sa_len, luser, ruser);
580 }
581 
582 /*
583  * Returns 0 if ok, -1 if not ok.
584  */
585 int
586 __ivaliduser_sa(hostf, raddr, salen, luser, ruser)
587 	FILE *hostf;
588 	const struct sockaddr *raddr;
589 	socklen_t salen;
590 	const char *luser, *ruser;
591 {
592 	register char *user, *p;
593 	int ch;
594 	char buf[MAXHOSTNAMELEN + 128];		/* host + login */
595 	char hname[MAXHOSTNAMELEN];
596 	/* Presumed guilty until proven innocent. */
597 	int userok = 0, hostok = 0;
598 	int h_error;
599 #ifdef YP
600 	char *ypdomain;
601 
602 	if (yp_get_default_domain(&ypdomain))
603 		ypdomain = NULL;
604 #else
605 #define	ypdomain NULL
606 #endif
607 	/* We need to get the damn hostname back for netgroup matching. */
608 	if (getnameinfo(raddr, salen, hname, sizeof(hname), NULL, 0,
609 			NI_NAMEREQD) != 0)
610 		return (-1);
611 
612 	while (fgets(buf, sizeof(buf), hostf)) {
613 		p = buf;
614 		/* Skip lines that are too long. */
615 		if (strchr(p, '\n') == NULL) {
616 			while ((ch = getc(hostf)) != '\n' && ch != EOF);
617 			continue;
618 		}
619 		if (*p == '\n' || *p == '#') {
620 			/* comment... */
621 			continue;
622 		}
623 		while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
624 			*p = isupper((unsigned char)*p) ? tolower((unsigned char)*p) : *p;
625 			p++;
626 		}
627 		if (*p == ' ' || *p == '\t') {
628 			*p++ = '\0';
629 			while (*p == ' ' || *p == '\t')
630 				p++;
631 			user = p;
632 			while (*p != '\n' && *p != ' ' &&
633 			    *p != '\t' && *p != '\0')
634 				p++;
635 		} else
636 			user = p;
637 		*p = '\0';
638 		/*
639 		 * Do +/- and +@/-@ checking. This looks really nasty,
640 		 * but it matches SunOS's behavior so far as I can tell.
641 		 */
642 		switch(buf[0]) {
643 		case '+':
644 			if (!buf[1]) {     /* '+' matches all hosts */
645 				hostok = 1;
646 				break;
647 			}
648 			if (buf[1] == '@')  /* match a host by netgroup */
649 				hostok = innetgr((char *)&buf[2],
650 					(char *)&hname, NULL, ypdomain);
651 			else		/* match a host by addr */
652 				hostok = __icheckhost(raddr, salen,
653 						      (char *)&buf[1]);
654 			break;
655 		case '-':     /* reject '-' hosts and all their users */
656 			if (buf[1] == '@') {
657 				if (innetgr((char *)&buf[2],
658 					      (char *)&hname, NULL, ypdomain))
659 					return(-1);
660 			} else {
661 				if (__icheckhost(raddr, salen,
662 						 (char *)&buf[1]))
663 					return(-1);
664 			}
665 			break;
666 		default:  /* if no '+' or '-', do a simple match */
667 			hostok = __icheckhost(raddr, salen, buf);
668 			break;
669 		}
670 		switch(*user) {
671 		case '+':
672 			if (!*(user+1)) {      /* '+' matches all users */
673 				userok = 1;
674 				break;
675 			}
676 			if (*(user+1) == '@')  /* match a user by netgroup */
677 				userok = innetgr(user+2, NULL, ruser, ypdomain);
678 			else	   /* match a user by direct specification */
679 				userok = !(strcmp(ruser, user+1));
680 			break;
681 		case '-': 		/* if we matched a hostname, */
682 			if (hostok) {   /* check for user field rejections */
683 				if (!*(user+1))
684 					return(-1);
685 				if (*(user+1) == '@') {
686 					if (innetgr(user+2, NULL,
687 							ruser, ypdomain))
688 						return(-1);
689 				} else {
690 					if (!strcmp(ruser, user+1))
691 						return(-1);
692 				}
693 			}
694 			break;
695 		default:	/* no rejections: try to match the user */
696 			if (hostok)
697 				userok = !(strcmp(ruser,*user ? user : luser));
698 			break;
699 		}
700 		if (hostok && userok)
701 			return(0);
702 	}
703 	return (-1);
704 }
705 
706 /*
707  * Returns "true" if match, 0 if no match.
708  *
709  * NI_WITHSCOPEID is useful for comparing sin6_scope_id portion
710  * if af == AF_INET6.
711  */
712 static int
713 __icheckhost(raddr, salen, lhost)
714 	const struct sockaddr *raddr;
715 	socklen_t salen;
716         const char *lhost;
717 {
718 	struct sockaddr_in sin;
719 	struct sockaddr_in6 *sin6;
720 	struct addrinfo hints, *res, *r;
721 	int error;
722 	char h1[NI_MAXHOST], h2[NI_MAXHOST];
723 
724 	if (raddr->sa_family == AF_INET6) {
725 		sin6 = (struct sockaddr_in6 *)raddr;
726 		if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
727 			memset(&sin, 0, sizeof(sin));
728 			sin.sin_family = AF_INET;
729 			sin.sin_len = sizeof(struct sockaddr_in);
730 			memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12],
731 			       sizeof(sin.sin_addr));
732 			raddr = (struct sockaddr *)&sin;
733 			salen = sin.sin_len;
734 		}
735 	}
736 
737 	h1[0] = '\0';
738 	if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
739 			NI_NUMERICHOST | NI_WITHSCOPEID) != 0)
740 		return (0);
741 
742 	/* Resolve laddr into sockaddr */
743 	memset(&hints, 0, sizeof(hints));
744 	hints.ai_family = raddr->sa_family;
745 	hints.ai_socktype = SOCK_DGRAM;	/*XXX dummy*/
746 	res = NULL;
747 	error = getaddrinfo(lhost, "0", &hints, &res);
748 	if (error)
749 		return (0);
750 
751 	for (r = res; r ; r = r->ai_next) {
752 		h2[0] = '\0';
753 		if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
754 				NULL, 0, NI_NUMERICHOST | NI_WITHSCOPEID) != 0)
755 			continue;
756 		if (strcmp(h1, h2) == 0) {
757 			freeaddrinfo(res);
758 			return (1);
759 		}
760 	}
761 
762 	/* No match. */
763 	freeaddrinfo(res);
764 	return (0);
765 }
766