xref: /freebsd/lib/libc/net/rcmd.c (revision ca9ac06c99bfd0150b85d4d83c396ce6237c0e05)
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 
34 #if defined(LIBC_SCCS) && !defined(lint)
35 static char sccsid[] = "@(#)rcmd.c	8.3 (Berkeley) 3/26/94";
36 #endif /* LIBC_SCCS and not lint */
37 #include <sys/cdefs.h>
38 __FBSDID("$FreeBSD$");
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 <stdlib.h>
52 #include <unistd.h>
53 #include <pwd.h>
54 #include <errno.h>
55 #include <stdio.h>
56 #include <ctype.h>
57 #include <string.h>
58 #include <rpc/rpc.h>
59 #ifdef YP
60 #include <rpcsvc/yp_prot.h>
61 #include <rpcsvc/ypclnt.h>
62 #endif
63 #include <arpa/nameser.h>
64 #include "un-namespace.h"
65 
66 /* wrapper for KAME-special getnameinfo() */
67 #ifndef NI_WITHSCOPEID
68 #define NI_WITHSCOPEID	0
69 #endif
70 
71 extern int innetgr( const char *, const char *, const char *, const char * );
72 
73 #define max(a, b)	((a > b) ? a : b)
74 
75 int __ivaliduser(FILE *, u_int32_t, const char *, const char *);
76 int __ivaliduser_af(FILE *,const void *, const char *, const char *, int, int);
77 int __ivaliduser_sa(FILE *, const struct sockaddr *, socklen_t, const char *,
78     const char *);
79 static int __icheckhost(const struct sockaddr *, socklen_t, const char *);
80 
81 char paddr[NI_MAXHOST];
82 
83 int
84 rcmd(ahost, rport, locuser, remuser, cmd, fd2p)
85 	char **ahost;
86 	u_short rport;
87 	const char *locuser, *remuser, *cmd;
88 	int *fd2p;
89 {
90 	return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
91 }
92 
93 int
94 rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, af)
95 	char **ahost;
96 	u_short rport;
97 	const char *locuser, *remuser, *cmd;
98 	int *fd2p;
99 	int af;
100 {
101 	struct addrinfo hints, *res, *ai;
102 	struct sockaddr_storage from;
103 	fd_set reads;
104 	sigset_t oldmask, newmask;
105 	pid_t pid;
106 	int s, aport, lport, timo, error;
107 	char c, *p;
108 	int refused, nres;
109 	char num[8];
110 	static char canonnamebuf[MAXDNAME];	/* is it proper here? */
111 
112 	/* call rcmdsh() with specified remote shell if appropriate. */
113 	if (!issetugid() && (p = getenv("RSH"))) {
114 		struct servent *sp = getservbyname("shell", "tcp");
115 
116 		if (sp && sp->s_port == rport)
117 			return (rcmdsh(ahost, rport, locuser, remuser,
118 			    cmd, p));
119 	}
120 
121 	/* use rsh(1) if non-root and remote port is shell. */
122 	if (geteuid()) {
123 		struct servent *sp = getservbyname("shell", "tcp");
124 
125 		if (sp && sp->s_port == rport)
126 			return (rcmdsh(ahost, rport, locuser, remuser,
127 			    cmd, NULL));
128 	}
129 
130 	pid = getpid();
131 
132 	memset(&hints, 0, sizeof(hints));
133 	hints.ai_flags = AI_CANONNAME;
134 	hints.ai_family = af;
135 	hints.ai_socktype = SOCK_STREAM;
136 	hints.ai_protocol = 0;
137 	(void)snprintf(num, sizeof(num), "%d", ntohs(rport));
138 	error = getaddrinfo(*ahost, num, &hints, &res);
139 	if (error) {
140 		fprintf(stderr, "rcmd: getaddrinfo: %s\n",
141 			gai_strerror(error));
142 		if (error == EAI_SYSTEM)
143 			fprintf(stderr, "rcmd: getaddrinfo: %s\n",
144 				strerror(errno));
145 		return (-1);
146 	}
147 
148 	if (res->ai_canonname
149 	 && strlen(res->ai_canonname) + 1 < sizeof(canonnamebuf)) {
150 		strncpy(canonnamebuf, res->ai_canonname, sizeof(canonnamebuf));
151 		*ahost = canonnamebuf;
152 	}
153 	nres = 0;
154 	for (ai = res; ai; ai = ai->ai_next)
155 		nres++;
156 	ai = res;
157 	refused = 0;
158 	sigemptyset(&newmask);
159 	sigaddset(&newmask, SIGURG);
160 	_sigprocmask(SIG_BLOCK, (const sigset_t *)&newmask, &oldmask);
161 	for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
162 		s = rresvport_af(&lport, ai->ai_family);
163 		if (s < 0) {
164 			if (errno != EAGAIN && ai->ai_next) {
165 				ai = ai->ai_next;
166 				continue;
167 			}
168 			if (errno == EAGAIN)
169 				(void)fprintf(stderr,
170 				    "rcmd: socket: All ports in use\n");
171 			else
172 				(void)fprintf(stderr, "rcmd: socket: %s\n",
173 				    strerror(errno));
174 			freeaddrinfo(res);
175 			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
176 			    NULL);
177 			return (-1);
178 		}
179 		_fcntl(s, F_SETOWN, pid);
180 		if (_connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
181 			break;
182 		(void)_close(s);
183 		if (errno == EADDRINUSE) {
184 			lport--;
185 			continue;
186 		}
187 		if (errno == ECONNREFUSED)
188 			refused = 1;
189 		if (ai->ai_next == NULL && (!refused || timo > 16)) {
190 			(void)fprintf(stderr, "%s: %s\n",
191 				      *ahost, strerror(errno));
192 			freeaddrinfo(res);
193 			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
194 			    NULL);
195 			return (-1);
196 		}
197 		if (nres > 1) {
198 			int oerrno = errno;
199 
200 			getnameinfo(ai->ai_addr, ai->ai_addrlen,
201 				    paddr, sizeof(paddr),
202 				    NULL, 0,
203 				    NI_NUMERICHOST|NI_WITHSCOPEID);
204 			(void)fprintf(stderr, "connect to address %s: ",
205 				      paddr);
206 			errno = oerrno;
207 			perror(0);
208 		}
209 		if ((ai = ai->ai_next) == NULL) {
210 			/* refused && timo <= 16 */
211 			struct timespec time_to_sleep, time_remaining;
212 
213 			time_to_sleep.tv_sec = timo;
214 			time_to_sleep.tv_nsec = 0;
215 			(void)_nanosleep(&time_to_sleep, &time_remaining);
216 			timo *= 2;
217 			ai = res;
218 			refused = 0;
219 		}
220 		if (nres > 1) {
221 			getnameinfo(ai->ai_addr, ai->ai_addrlen,
222 				    paddr, sizeof(paddr),
223 				    NULL, 0,
224 				    NI_NUMERICHOST|NI_WITHSCOPEID);
225 			fprintf(stderr, "Trying %s...\n", paddr);
226 		}
227 	}
228 	lport--;
229 	if (fd2p == 0) {
230 		_write(s, "", 1);
231 		lport = 0;
232 	} else {
233 		int s2 = rresvport_af(&lport, ai->ai_family), s3;
234 		socklen_t len = ai->ai_addrlen;
235 		int nfds;
236 
237 		if (s2 < 0)
238 			goto bad;
239 		_listen(s2, 1);
240 		(void)snprintf(num, sizeof(num), "%d", lport);
241 		if (_write(s, num, strlen(num)+1) != strlen(num)+1) {
242 			(void)fprintf(stderr,
243 			    "rcmd: write (setting up stderr): %s\n",
244 			    strerror(errno));
245 			(void)_close(s2);
246 			goto bad;
247 		}
248 		nfds = max(s, s2)+1;
249 		if(nfds > FD_SETSIZE) {
250 			fprintf(stderr, "rcmd: too many files\n");
251 			(void)_close(s2);
252 			goto bad;
253 		}
254 again:
255 		FD_ZERO(&reads);
256 		FD_SET(s, &reads);
257 		FD_SET(s2, &reads);
258 		errno = 0;
259 		if (_select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){
260 			if (errno != 0)
261 				(void)fprintf(stderr,
262 				    "rcmd: select (setting up stderr): %s\n",
263 				    strerror(errno));
264 			else
265 				(void)fprintf(stderr,
266 				"select: protocol failure in circuit setup\n");
267 			(void)_close(s2);
268 			goto bad;
269 		}
270 		s3 = _accept(s2, (struct sockaddr *)&from, &len);
271 		switch (from.ss_family) {
272 		case AF_INET:
273 			aport = ntohs(((struct sockaddr_in *)&from)->sin_port);
274 			break;
275 #ifdef INET6
276 		case AF_INET6:
277 			aport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
278 			break;
279 #endif
280 		default:
281 			aport = 0;	/* error */
282 			break;
283 		}
284 		/*
285 		 * XXX careful for ftp bounce attacks. If discovered, shut them
286 		 * down and check for the real auxiliary channel to connect.
287 		 */
288 		if (aport == 20) {
289 			_close(s3);
290 			goto again;
291 		}
292 		(void)_close(s2);
293 		if (s3 < 0) {
294 			(void)fprintf(stderr,
295 			    "rcmd: accept: %s\n", strerror(errno));
296 			lport = 0;
297 			goto bad;
298 		}
299 		*fd2p = s3;
300 		if (aport >= IPPORT_RESERVED || aport < IPPORT_RESERVED / 2) {
301 			(void)fprintf(stderr,
302 			    "socket: protocol failure in circuit setup.\n");
303 			goto bad2;
304 		}
305 	}
306 	(void)_write(s, locuser, strlen(locuser)+1);
307 	(void)_write(s, remuser, strlen(remuser)+1);
308 	(void)_write(s, cmd, strlen(cmd)+1);
309 	if (_read(s, &c, 1) != 1) {
310 		(void)fprintf(stderr,
311 		    "rcmd: %s: %s\n", *ahost, strerror(errno));
312 		goto bad2;
313 	}
314 	if (c != 0) {
315 		while (_read(s, &c, 1) == 1) {
316 			(void)_write(STDERR_FILENO, &c, 1);
317 			if (c == '\n')
318 				break;
319 		}
320 		goto bad2;
321 	}
322 	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
323 	freeaddrinfo(res);
324 	return (s);
325 bad2:
326 	if (lport)
327 		(void)_close(*fd2p);
328 bad:
329 	(void)_close(s);
330 	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
331 	freeaddrinfo(res);
332 	return (-1);
333 }
334 
335 int
336 rresvport(port)
337 	int *port;
338 {
339 	return rresvport_af(port, AF_INET);
340 }
341 
342 int
343 rresvport_af(alport, family)
344 	int *alport, family;
345 {
346 	int s;
347 	struct sockaddr_storage ss;
348 	u_short *sport;
349 
350 	memset(&ss, 0, sizeof(ss));
351 	ss.ss_family = family;
352 	switch (family) {
353 	case AF_INET:
354 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in);
355 		sport = &((struct sockaddr_in *)&ss)->sin_port;
356 		((struct sockaddr_in *)&ss)->sin_addr.s_addr = INADDR_ANY;
357 		break;
358 #ifdef INET6
359 	case AF_INET6:
360 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in6);
361 		sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
362 		((struct sockaddr_in6 *)&ss)->sin6_addr = in6addr_any;
363 		break;
364 #endif
365 	default:
366 		errno = EAFNOSUPPORT;
367 		return -1;
368 	}
369 
370 	s = _socket(ss.ss_family, SOCK_STREAM, 0);
371 	if (s < 0)
372 		return (-1);
373 #if 0 /* compat_exact_traditional_rresvport_semantics */
374 	sin.sin_port = htons((u_short)*alport);
375 	if (_bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
376 		return (s);
377 	if (errno != EADDRINUSE) {
378 		(void)_close(s);
379 		return (-1);
380 	}
381 #endif
382 	*sport = 0;
383 	if (bindresvport_sa(s, (struct sockaddr *)&ss) == -1) {
384 		(void)_close(s);
385 		return (-1);
386 	}
387 	*alport = (int)ntohs(*sport);
388 	return (s);
389 }
390 
391 int	__check_rhosts_file = 1;
392 char	*__rcmd_errstr;
393 
394 int
395 ruserok(rhost, superuser, ruser, luser)
396 	const char *rhost, *ruser, *luser;
397 	int superuser;
398 {
399 	struct addrinfo hints, *res, *r;
400 	int error;
401 
402 	memset(&hints, 0, sizeof(hints));
403 	hints.ai_family = PF_UNSPEC;
404 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
405 	error = getaddrinfo(rhost, "0", &hints, &res);
406 	if (error)
407 		return (-1);
408 
409 	for (r = res; r; r = r->ai_next) {
410 		if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
411 		    luser) == 0) {
412 			freeaddrinfo(res);
413 			return (0);
414 		}
415 	}
416 	freeaddrinfo(res);
417 	return (-1);
418 }
419 
420 /*
421  * New .rhosts strategy: We are passed an ip address. We spin through
422  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
423  * has ip addresses, we don't have to trust a nameserver.  When it
424  * contains hostnames, we spin through the list of addresses the nameserver
425  * gives us and look for a match.
426  *
427  * Returns 0 if ok, -1 if not ok.
428  */
429 int
430 iruserok(raddr, superuser, ruser, luser)
431 	unsigned long raddr;
432 	int superuser;
433 	const char *ruser, *luser;
434 {
435 	struct sockaddr_in sin;
436 
437 	memset(&sin, 0, sizeof(sin));
438 	sin.sin_family = AF_INET;
439 	sin.sin_len = sizeof(struct sockaddr_in);
440 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
441 	return iruserok_sa((struct sockaddr *)&sin, sin.sin_len, superuser,
442 		ruser, luser);
443 }
444 
445 /*
446  * AF independent extension of iruserok.
447  *
448  * Returns 0 if ok, -1 if not ok.
449  */
450 int
451 iruserok_sa(ra, rlen, superuser, ruser, luser)
452 	const void *ra;
453 	int rlen;
454 	int superuser;
455 	const char *ruser, *luser;
456 {
457 	char *cp;
458 	struct stat sbuf;
459 	struct passwd *pwd;
460 	FILE *hostf;
461 	uid_t uid;
462 	int first;
463 	char pbuf[MAXPATHLEN];
464 	const struct sockaddr *raddr;
465 	struct sockaddr_storage ss;
466 
467 	/* avoid alignment issue */
468 	if (rlen > sizeof(ss))
469 		return(-1);
470 	memcpy(&ss, ra, rlen);
471 	raddr = (struct sockaddr *)&ss;
472 
473 	first = 1;
474 	hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
475 again:
476 	if (hostf) {
477 		if (__ivaliduser_sa(hostf, raddr, rlen, luser, ruser) == 0) {
478 			(void)fclose(hostf);
479 			return (0);
480 		}
481 		(void)fclose(hostf);
482 	}
483 	if (first == 1 && (__check_rhosts_file || superuser)) {
484 		first = 0;
485 		if ((pwd = getpwnam(luser)) == NULL)
486 			return (-1);
487 		(void)strcpy(pbuf, pwd->pw_dir);
488 		(void)strcat(pbuf, "/.rhosts");
489 
490 		/*
491 		 * Change effective uid while opening .rhosts.  If root and
492 		 * reading an NFS mounted file system, can't read files that
493 		 * are protected read/write owner only.
494 		 */
495 		uid = geteuid();
496 		(void)seteuid(pwd->pw_uid);
497 		hostf = fopen(pbuf, "r");
498 		(void)seteuid(uid);
499 
500 		if (hostf == NULL)
501 			return (-1);
502 		/*
503 		 * If not a regular file, or is owned by someone other than
504 		 * user or root or if writeable by anyone but the owner, quit.
505 		 */
506 		cp = NULL;
507 		if (lstat(pbuf, &sbuf) < 0)
508 			cp = ".rhosts lstat failed";
509 		else if (!S_ISREG(sbuf.st_mode))
510 			cp = ".rhosts not regular file";
511 		else if (_fstat(fileno(hostf), &sbuf) < 0)
512 			cp = ".rhosts fstat failed";
513 		else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
514 			cp = "bad .rhosts owner";
515 		else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
516 			cp = ".rhosts writeable by other than owner";
517 		/* If there were any problems, quit. */
518 		if (cp) {
519 			__rcmd_errstr = cp;
520 			(void)fclose(hostf);
521 			return (-1);
522 		}
523 		goto again;
524 	}
525 	return (-1);
526 }
527 
528 /*
529  * XXX
530  * Don't make static, used by lpd(8).
531  *
532  * Returns 0 if ok, -1 if not ok.
533  */
534 int
535 __ivaliduser(hostf, raddr, luser, ruser)
536 	FILE *hostf;
537 	u_int32_t raddr;
538 	const char *luser, *ruser;
539 {
540 	struct sockaddr_in sin;
541 
542 	memset(&sin, 0, sizeof(sin));
543 	sin.sin_family = AF_INET;
544 	sin.sin_len = sizeof(struct sockaddr_in);
545 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
546 	return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
547 		luser, ruser);
548 }
549 
550 /*
551  * Returns 0 if ok, -1 if not ok.
552  *
553  * XXX obsolete API.
554  */
555 int
556 __ivaliduser_af(hostf, raddr, luser, ruser, af, len)
557 	FILE *hostf;
558 	const void *raddr;
559 	const char *luser, *ruser;
560 	int af, len;
561 {
562 	struct sockaddr *sa = NULL;
563 	struct sockaddr_in *sin = NULL;
564 #ifdef INET6
565 	struct sockaddr_in6 *sin6 = NULL;
566 #endif
567 	struct sockaddr_storage ss;
568 
569 	memset(&ss, 0, sizeof(ss));
570 	switch (af) {
571 	case AF_INET:
572 		if (len != sizeof(sin->sin_addr))
573 			return -1;
574 		sin = (struct sockaddr_in *)&ss;
575 		sin->sin_family = AF_INET;
576 		sin->sin_len = sizeof(struct sockaddr_in);
577 		memcpy(&sin->sin_addr, raddr, sizeof(sin->sin_addr));
578 		break;
579 #ifdef INET6
580 	case AF_INET6:
581 		if (len != sizeof(sin6->sin6_addr))
582 			return -1;
583 		/* you will lose scope info */
584 		sin6 = (struct sockaddr_in6 *)&ss;
585 		sin6->sin6_family = AF_INET6;
586 		sin6->sin6_len = sizeof(struct sockaddr_in6);
587 		memcpy(&sin6->sin6_addr, raddr, sizeof(sin6->sin6_addr));
588 		break;
589 #endif
590 	default:
591 		return -1;
592 	}
593 
594 	sa = (struct sockaddr *)&ss;
595 	return __ivaliduser_sa(hostf, sa, sa->sa_len, luser, ruser);
596 }
597 
598 int
599 __ivaliduser_sa(hostf, raddr, salen, luser, ruser)
600 	FILE *hostf;
601 	const struct sockaddr *raddr;
602 	socklen_t salen;
603 	const char *luser, *ruser;
604 {
605 	char *user, *p;
606 	int ch;
607 	char buf[MAXHOSTNAMELEN + 128];		/* host + login */
608 	char hname[MAXHOSTNAMELEN];
609 	/* Presumed guilty until proven innocent. */
610 	int userok = 0, hostok = 0;
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