xref: /dragonfly/lib/libc/net/rcmd.c (revision 678e8cc6)
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. 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  * @(#)rcmd.c	8.3 (Berkeley) 3/26/94
30  * $FreeBSD: src/lib/libc/net/rcmd.c,v 1.42 2007/01/09 00:28:02 imp Exp $
31  */
32 
33 #include "namespace.h"
34 #include <sys/param.h>
35 #include <sys/socket.h>
36 #include <sys/stat.h>
37 
38 #include <netinet/in.h>
39 #include <arpa/inet.h>
40 
41 #include <signal.h>
42 #include <fcntl.h>
43 #include <netdb.h>
44 #include <stdlib.h>
45 #include <unistd.h>
46 #include <pwd.h>
47 #include <errno.h>
48 #include <stdio.h>
49 #include <ctype.h>
50 #include <string.h>
51 #include <rpc/rpc.h>
52 #ifdef YP
53 #include <rpcsvc/yp_prot.h>
54 #include <rpcsvc/ypclnt.h>
55 #endif
56 #include <arpa/nameser.h>
57 #include "un-namespace.h"
58 
59 extern int innetgr(const char *, const char *, const char *, const char *);
60 
61 #define max(a, b)	((a > b) ? a : b)
62 
63 int __ivaliduser(FILE *, u_int32_t, const char *, const char *);
64 int __ivaliduser_af(FILE *,const void *, const char *, const char *, int, int);
65 int __ivaliduser_sa(FILE *, const struct sockaddr *, socklen_t, const char *,
66 		    const char *);
67 static int __icheckhost(const struct sockaddr *, socklen_t, const char *);
68 
69 char paddr[NI_MAXHOST];
70 
71 int
rcmd(char ** ahost,int rport,const char * locuser,const char * remuser,const char * cmd,int * fd2p)72 rcmd(char **ahost, int rport, const char *locuser, const char *remuser,
73      const char *cmd, int *fd2p)
74 {
75 	return rcmd_af(ahost, rport, locuser, remuser, cmd, fd2p, AF_INET);
76 }
77 
78 int
rcmd_af(char ** ahost,int rport,const char * locuser,const char * remuser,const char * cmd,int * fd2p,int af)79 rcmd_af(char **ahost, int rport, const char *locuser, const char *remuser,
80 	const char *cmd, int *fd2p, int af)
81 {
82 	struct addrinfo hints, *res, *ai;
83 	struct sockaddr_storage from;
84 	fd_set reads;
85 	sigset_t oldmask, newmask;
86 	pid_t pid;
87 	int s, aport, lport, timo, error;
88 	char c, *p;
89 	int refused, nres;
90 	char num[8];
91 	static char canonnamebuf[MAXDNAME];	/* is it proper here? */
92 
93 	/* call rcmdsh() with specified remote shell if appropriate. */
94 	if (!issetugid() && (p = getenv("RSH"))) {
95 		struct servent *sp = getservbyname("shell", "tcp");
96 
97 		if (sp && sp->s_port == rport)
98 			return (rcmdsh(ahost, rport, locuser, remuser,
99 			    cmd, p));
100 	}
101 
102 	/* use rsh(1) if non-root and remote port is shell. */
103 	if (geteuid()) {
104 		struct servent *sp = getservbyname("shell", "tcp");
105 
106 		if (sp && sp->s_port == rport)
107 			return (rcmdsh(ahost, rport, locuser, remuser,
108 			    cmd, NULL));
109 	}
110 
111 	pid = getpid();
112 
113 	memset(&hints, 0, sizeof(hints));
114 	hints.ai_flags = AI_CANONNAME;
115 	hints.ai_family = af;
116 	hints.ai_socktype = SOCK_STREAM;
117 	hints.ai_protocol = 0;
118 	snprintf(num, sizeof(num), "%d", ntohs(rport));
119 	error = getaddrinfo(*ahost, num, &hints, &res);
120 	if (error) {
121 		fprintf(stderr, "rcmd: getaddrinfo: %s\n",
122 			gai_strerror(error));
123 		if (error == EAI_SYSTEM)
124 			fprintf(stderr, "rcmd: getaddrinfo: %s\n",
125 				strerror(errno));
126 		return (-1);
127 	}
128 
129 	if (res->ai_canonname &&
130 	    strlen(res->ai_canonname) + 1 < sizeof(canonnamebuf)) {
131 		strncpy(canonnamebuf, res->ai_canonname, sizeof(canonnamebuf));
132 		*ahost = canonnamebuf;
133 	}
134 	nres = 0;
135 	for (ai = res; ai; ai = ai->ai_next)
136 		nres++;
137 	ai = res;
138 	refused = 0;
139 	sigemptyset(&newmask);
140 	sigaddset(&newmask, SIGURG);
141 	_sigprocmask(SIG_BLOCK, (const sigset_t *)&newmask, &oldmask);
142 	for (timo = 1, lport = IPPORT_RESERVED - 1;;) {
143 		s = rresvport_af(&lport, ai->ai_family);
144 		if (s < 0) {
145 			if (errno != EAGAIN && ai->ai_next) {
146 				ai = ai->ai_next;
147 				continue;
148 			}
149 			if (errno == EAGAIN)
150 				fprintf(stderr,
151 				    "rcmd: socket: All ports in use\n");
152 			else
153 				fprintf(stderr, "rcmd: socket: %s\n",
154 				    strerror(errno));
155 			freeaddrinfo(res);
156 			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
157 			    NULL);
158 			return (-1);
159 		}
160 		_fcntl(s, F_SETOWN, pid);
161 		if (_connect(s, ai->ai_addr, ai->ai_addrlen) >= 0)
162 			break;
163 		_close(s);
164 		if (errno == EADDRINUSE) {
165 			lport--;
166 			continue;
167 		}
168 		if (errno == ECONNREFUSED)
169 			refused = 1;
170 		if (ai->ai_next == NULL && (!refused || timo > 16)) {
171 			fprintf(stderr, "%s: %s\n", *ahost, strerror(errno));
172 			freeaddrinfo(res);
173 			_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask,
174 			    NULL);
175 			return (-1);
176 		}
177 		if (nres > 1) {
178 			int oerrno = errno;
179 
180 			getnameinfo(ai->ai_addr, ai->ai_addrlen, paddr,
181 			    sizeof(paddr), NULL, 0, NI_NUMERICHOST);
182 			fprintf(stderr, "connect to address %s: ", paddr);
183 			errno = oerrno;
184 			perror(0);
185 		}
186 		if ((ai = ai->ai_next) == NULL) {
187 			/* refused && timo <= 16 */
188 			struct timespec time_to_sleep, time_remaining;
189 
190 			time_to_sleep.tv_sec = timo;
191 			time_to_sleep.tv_nsec = 0;
192 			_nanosleep(&time_to_sleep, &time_remaining);
193 			timo *= 2;
194 			ai = res;
195 			refused = 0;
196 		}
197 		if (nres > 1) {
198 			getnameinfo(ai->ai_addr, ai->ai_addrlen, paddr,
199 			    sizeof(paddr), NULL, 0, NI_NUMERICHOST);
200 			fprintf(stderr, "Trying %s...\n", paddr);
201 		}
202 	}
203 	lport--;
204 	if (fd2p == NULL) {
205 		_write(s, "", 1);
206 		lport = 0;
207 	} else {
208 		int s2 = rresvport_af(&lport, ai->ai_family), s3;
209 		socklen_t len = ai->ai_addrlen;
210 		int nfds;
211 
212 		if (s2 < 0)
213 			goto bad;
214 		_listen(s2, 1);
215 		snprintf(num, sizeof(num), "%d", lport);
216 		if (_write(s, num, strlen(num)+1) != strlen(num)+1) {
217 			fprintf(stderr,
218 			    "rcmd: write (setting up stderr): %s\n",
219 			    strerror(errno));
220 			_close(s2);
221 			goto bad;
222 		}
223 		nfds = max(s, s2)+1;
224 		if(nfds > FD_SETSIZE) {
225 			fprintf(stderr, "rcmd: too many files\n");
226 			_close(s2);
227 			goto bad;
228 		}
229 again:
230 		FD_ZERO(&reads);
231 		FD_SET(s, &reads);
232 		FD_SET(s2, &reads);
233 		errno = 0;
234 		if (_select(nfds, &reads, 0, 0, 0) < 1 || !FD_ISSET(s2, &reads)){
235 			if (errno != 0)
236 				fprintf(stderr,
237 				    "rcmd: select (setting up stderr): %s\n",
238 				    strerror(errno));
239 			else
240 				fprintf(stderr,
241 				"select: protocol failure in circuit setup\n");
242 			_close(s2);
243 			goto bad;
244 		}
245 		s3 = _accept(s2, (struct sockaddr *)&from, &len);
246 		switch (from.ss_family) {
247 		case AF_INET:
248 			aport = ntohs(((struct sockaddr_in *)&from)->sin_port);
249 			break;
250 #ifdef INET6
251 		case AF_INET6:
252 			aport = ntohs(((struct sockaddr_in6 *)&from)->sin6_port);
253 			break;
254 #endif
255 		default:
256 			aport = 0;	/* error */
257 			break;
258 		}
259 		/*
260 		 * XXX careful for ftp bounce attacks. If discovered, shut them
261 		 * down and check for the real auxiliary channel to connect.
262 		 */
263 		if (aport == 20) {
264 			_close(s3);
265 			goto again;
266 		}
267 		_close(s2);
268 		if (s3 < 0) {
269 			fprintf(stderr,
270 			    "rcmd: accept: %s\n", strerror(errno));
271 			lport = 0;
272 			goto bad;
273 		}
274 		*fd2p = s3;
275 		if (aport >= IPPORT_RESERVED || aport < IPPORT_RESERVED / 2) {
276 			fprintf(stderr,
277 			    "socket: protocol failure in circuit setup.\n");
278 			goto bad2;
279 		}
280 	}
281 	_write(s, locuser, strlen(locuser)+1);
282 	_write(s, remuser, strlen(remuser)+1);
283 	_write(s, cmd, strlen(cmd)+1);
284 	if (_read(s, &c, 1) != 1) {
285 		fprintf(stderr,
286 		    "rcmd: %s: %s\n", *ahost, strerror(errno));
287 		goto bad2;
288 	}
289 	if (c != 0) {
290 		while (_read(s, &c, 1) == 1) {
291 			_write(STDERR_FILENO, &c, 1);
292 			if (c == '\n')
293 				break;
294 		}
295 		goto bad2;
296 	}
297 	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
298 	freeaddrinfo(res);
299 	return (s);
300 bad2:
301 	if (lport)
302 		_close(*fd2p);
303 bad:
304 	_close(s);
305 	_sigprocmask(SIG_SETMASK, (const sigset_t *)&oldmask, NULL);
306 	freeaddrinfo(res);
307 	return (-1);
308 }
309 
310 int
rresvport(int * port)311 rresvport(int *port)
312 {
313 	return rresvport_af(port, AF_INET);
314 }
315 
316 int
rresvport_af(int * alport,int family)317 rresvport_af(int *alport, int family)
318 {
319 	int s;
320 	struct sockaddr_storage ss;
321 	u_short *sport;
322 
323 	memset(&ss, 0, sizeof(ss));
324 	ss.ss_family = family;
325 	switch (family) {
326 	case AF_INET:
327 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in);
328 		sport = &((struct sockaddr_in *)&ss)->sin_port;
329 		((struct sockaddr_in *)&ss)->sin_addr.s_addr = INADDR_ANY;
330 		break;
331 #ifdef INET6
332 	case AF_INET6:
333 		((struct sockaddr *)&ss)->sa_len = sizeof(struct sockaddr_in6);
334 		sport = &((struct sockaddr_in6 *)&ss)->sin6_port;
335 		((struct sockaddr_in6 *)&ss)->sin6_addr = in6addr_any;
336 		break;
337 #endif
338 	default:
339 		errno = EAFNOSUPPORT;
340 		return -1;
341 	}
342 
343 	s = _socket(ss.ss_family, SOCK_STREAM, 0);
344 	if (s < 0)
345 		return (-1);
346 #if 0 /* compat_exact_traditional_rresvport_semantics */
347 	sin.sin_port = htons((u_short)*alport);
348 	if (_bind(s, (struct sockaddr *)&sin, sizeof(sin)) >= 0)
349 		return (s);
350 	if (errno != EADDRINUSE) {
351 		_close(s);
352 		return (-1);
353 	}
354 #endif
355 	*sport = 0;
356 	if (bindresvport_sa(s, (struct sockaddr *)&ss) == -1) {
357 		_close(s);
358 		return (-1);
359 	}
360 	*alport = (int)ntohs(*sport);
361 	return (s);
362 }
363 
364 int	__check_rhosts_file = 1;
365 char	*__rcmd_errstr;
366 
367 int
ruserok(const char * rhost,int superuser,const char * ruser,const char * luser)368 ruserok(const char *rhost, int superuser, const char *ruser, const char *luser)
369 {
370 	struct addrinfo hints, *res, *r;
371 	int error;
372 
373 	memset(&hints, 0, sizeof(hints));
374 	hints.ai_family = PF_UNSPEC;
375 	hints.ai_socktype = SOCK_DGRAM;	/*dummy*/
376 	error = getaddrinfo(rhost, "0", &hints, &res);
377 	if (error)
378 		return (-1);
379 
380 	for (r = res; r; r = r->ai_next) {
381 		if (iruserok_sa(r->ai_addr, r->ai_addrlen, superuser, ruser,
382 		    luser) == 0) {
383 			freeaddrinfo(res);
384 			return (0);
385 		}
386 	}
387 	freeaddrinfo(res);
388 	return (-1);
389 }
390 
391 /*
392  * New .rhosts strategy: We are passed an ip address. We spin through
393  * hosts.equiv and .rhosts looking for a match. When the .rhosts only
394  * has ip addresses, we don't have to trust a nameserver.  When it
395  * contains hostnames, we spin through the list of addresses the nameserver
396  * gives us and look for a match.
397  *
398  * Returns 0 if ok, -1 if not ok.
399  */
400 int
iruserok(unsigned long raddr,int superuser,const char * ruser,const char * luser)401 iruserok(unsigned long raddr, int superuser, const char *ruser,
402 	 const char *luser)
403 {
404 	struct sockaddr_in sin;
405 
406 	memset(&sin, 0, sizeof(sin));
407 	sin.sin_family = AF_INET;
408 	sin.sin_len = sizeof(struct sockaddr_in);
409 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
410 	return iruserok_sa((struct sockaddr *)&sin, sin.sin_len, superuser,
411 		ruser, luser);
412 }
413 
414 /*
415  * AF independent extension of iruserok.
416  *
417  * Returns 0 if ok, -1 if not ok.
418  */
419 int
iruserok_sa(const void * ra,int rlen,int superuser,const char * ruser,const char * luser)420 iruserok_sa(const void *ra, int rlen, int superuser, const char *ruser,
421 	    const char *luser)
422 {
423 	char *cp;
424 	struct stat sbuf;
425 	struct passwd *pwd;
426 	FILE *hostf;
427 	uid_t uid;
428 	int first;
429 	char pbuf[MAXPATHLEN];
430 	const struct sockaddr *raddr;
431 	struct sockaddr_storage ss;
432 
433 	/* avoid alignment issue */
434 	if (rlen > sizeof(ss))
435 		return(-1);
436 	memcpy(&ss, ra, rlen);
437 	raddr = (struct sockaddr *)&ss;
438 
439 	first = 1;
440 	hostf = superuser ? NULL : fopen(_PATH_HEQUIV, "r");
441 again:
442 	if (hostf) {
443 		if (__ivaliduser_sa(hostf, raddr, rlen, luser, ruser) == 0) {
444 			fclose(hostf);
445 			return (0);
446 		}
447 		fclose(hostf);
448 	}
449 	if (first == 1 && (__check_rhosts_file || superuser)) {
450 		first = 0;
451 		if ((pwd = getpwnam(luser)) == NULL)
452 			return (-1);
453 		strcpy(pbuf, pwd->pw_dir);
454 		strcat(pbuf, "/.rhosts");
455 
456 		/*
457 		 * Change effective uid while opening .rhosts.  If root and
458 		 * reading an NFS mounted file system, can't read files that
459 		 * are protected read/write owner only.
460 		 */
461 		uid = geteuid();
462 		seteuid(pwd->pw_uid);
463 		hostf = fopen(pbuf, "r");
464 		seteuid(uid);
465 
466 		if (hostf == NULL)
467 			return (-1);
468 		/*
469 		 * If not a regular file, or is owned by someone other than
470 		 * user or root or if writeable by anyone but the owner, quit.
471 		 */
472 		cp = NULL;
473 		if (lstat(pbuf, &sbuf) < 0)
474 			cp = ".rhosts lstat failed";
475 		else if (!S_ISREG(sbuf.st_mode))
476 			cp = ".rhosts not regular file";
477 		else if (_fstat(fileno(hostf), &sbuf) < 0)
478 			cp = ".rhosts fstat failed";
479 		else if (sbuf.st_uid && sbuf.st_uid != pwd->pw_uid)
480 			cp = "bad .rhosts owner";
481 		else if (sbuf.st_mode & (S_IWGRP|S_IWOTH))
482 			cp = ".rhosts writeable by other than owner";
483 		/* If there were any problems, quit. */
484 		if (cp) {
485 			__rcmd_errstr = cp;
486 			fclose(hostf);
487 			return (-1);
488 		}
489 		goto again;
490 	}
491 	return (-1);
492 }
493 
494 /*
495  * XXX
496  * Don't make static, used by lpd(8).
497  *
498  * Returns 0 if ok, -1 if not ok.
499  */
500 int
__ivaliduser(FILE * hostf,u_int32_t raddr,const char * luser,const char * ruser)501 __ivaliduser(FILE *hostf, u_int32_t raddr, const char *luser, const char *ruser)
502 {
503 	struct sockaddr_in sin;
504 
505 	memset(&sin, 0, sizeof(sin));
506 	sin.sin_family = AF_INET;
507 	sin.sin_len = sizeof(struct sockaddr_in);
508 	memcpy(&sin.sin_addr, &raddr, sizeof(sin.sin_addr));
509 	return __ivaliduser_sa(hostf, (struct sockaddr *)&sin, sin.sin_len,
510 		luser, ruser);
511 }
512 
513 /*
514  * Returns 0 if ok, -1 if not ok.
515  *
516  * XXX obsolete API.
517  */
518 int
__ivaliduser_af(FILE * hostf,const void * raddr,const char * luser,const char * ruser,int af,int len)519 __ivaliduser_af(FILE *hostf, const void *raddr, const char *luser,
520 		const char *ruser, int af, int len)
521 {
522 	struct sockaddr *sa = NULL;
523 	struct sockaddr_in *sin = NULL;
524 #ifdef INET6
525 	struct sockaddr_in6 *sin6 = NULL;
526 #endif
527 	struct sockaddr_storage ss;
528 
529 	memset(&ss, 0, sizeof(ss));
530 	switch (af) {
531 	case AF_INET:
532 		if (len != sizeof(sin->sin_addr))
533 			return -1;
534 		sin = (struct sockaddr_in *)&ss;
535 		sin->sin_family = AF_INET;
536 		sin->sin_len = sizeof(struct sockaddr_in);
537 		memcpy(&sin->sin_addr, raddr, sizeof(sin->sin_addr));
538 		break;
539 #ifdef INET6
540 	case AF_INET6:
541 		if (len != sizeof(sin6->sin6_addr))
542 			return -1;
543 		/* you will lose scope info */
544 		sin6 = (struct sockaddr_in6 *)&ss;
545 		sin6->sin6_family = AF_INET6;
546 		sin6->sin6_len = sizeof(struct sockaddr_in6);
547 		memcpy(&sin6->sin6_addr, raddr, sizeof(sin6->sin6_addr));
548 		break;
549 #endif
550 	default:
551 		return -1;
552 	}
553 
554 	sa = (struct sockaddr *)&ss;
555 	return __ivaliduser_sa(hostf, sa, sa->sa_len, luser, ruser);
556 }
557 
558 int
__ivaliduser_sa(FILE * hostf,const struct sockaddr * raddr,socklen_t salen,const char * luser,const char * ruser)559 __ivaliduser_sa(FILE *hostf, const struct sockaddr *raddr, socklen_t salen,
560 		const char *luser, const char *ruser)
561 {
562 	char *user, *p;
563 	int ch;
564 	char buf[MAXHOSTNAMELEN + 128];		/* host + login */
565 	char hname[MAXHOSTNAMELEN];
566 	/* Presumed guilty until proven innocent. */
567 	int userok = 0, hostok = 0;
568 #ifdef YP
569 	char *ypdomain;
570 
571 	if (yp_get_default_domain(&ypdomain))
572 		ypdomain = NULL;
573 #else
574 #define	ypdomain NULL
575 #endif
576 	/* We need to get the damn hostname back for netgroup matching. */
577 	if (getnameinfo(raddr, salen, hname, sizeof(hname), NULL, 0,
578 			NI_NAMEREQD) != 0)
579 		hname[0] = '\0';
580 
581 	while (fgets(buf, sizeof(buf), hostf)) {
582 		p = buf;
583 		/* Skip lines that are too long. */
584 		if (strchr(p, '\n') == NULL) {
585 			while ((ch = getc(hostf)) != '\n' && ch != EOF);
586 			continue;
587 		}
588 		if (*p == '\n' || *p == '#') {
589 			/* comment... */
590 			continue;
591 		}
592 		while (*p != '\n' && *p != ' ' && *p != '\t' && *p != '\0') {
593 			*p = isupper((unsigned char)*p) ? tolower((unsigned char)*p) : *p;
594 			p++;
595 		}
596 		if (*p == ' ' || *p == '\t') {
597 			*p++ = '\0';
598 			while (*p == ' ' || *p == '\t')
599 				p++;
600 			user = p;
601 			while (*p != '\n' && *p != ' ' &&
602 			    *p != '\t' && *p != '\0')
603 				p++;
604 		} else
605 			user = p;
606 		*p = '\0';
607 		/*
608 		 * Do +/- and +@/-@ checking. This looks really nasty,
609 		 * but it matches SunOS's behavior so far as I can tell.
610 		 */
611 		switch(buf[0]) {
612 		case '+':
613 			if (!buf[1]) {     /* '+' matches all hosts */
614 				hostok = 1;
615 				break;
616 			}
617 			if (buf[1] == '@')  /* match a host by netgroup */
618 				hostok = hname[0] != '\0' &&
619 				    innetgr(&buf[2], hname, NULL, ypdomain);
620 			else		/* match a host by addr */
621 				hostok = __icheckhost(raddr, salen,
622 						      (char *)&buf[1]);
623 			break;
624 		case '-':     /* reject '-' hosts and all their users */
625 			if (buf[1] == '@') {
626 				if (hname[0] == '\0' ||
627 				    innetgr(&buf[2], hname, NULL, ypdomain))
628 					return(-1);
629 			} else {
630 				if (__icheckhost(raddr, salen,
631 						 (char *)&buf[1]))
632 					return(-1);
633 			}
634 			break;
635 		default:  /* if no '+' or '-', do a simple match */
636 			hostok = __icheckhost(raddr, salen, buf);
637 			break;
638 		}
639 		switch(*user) {
640 		case '+':
641 			if (!*(user+1)) {      /* '+' matches all users */
642 				userok = 1;
643 				break;
644 			}
645 			if (*(user+1) == '@')  /* match a user by netgroup */
646 				userok = innetgr(user+2, NULL, ruser, ypdomain);
647 			else	   /* match a user by direct specification */
648 				userok = !(strcmp(ruser, user+1));
649 			break;
650 		case '-': 		/* if we matched a hostname, */
651 			if (hostok) {   /* check for user field rejections */
652 				if (!*(user+1))
653 					return(-1);
654 				if (*(user+1) == '@') {
655 					if (innetgr(user+2, NULL,
656 							ruser, ypdomain))
657 						return(-1);
658 				} else {
659 					if (!strcmp(ruser, user+1))
660 						return(-1);
661 				}
662 			}
663 			break;
664 		default:	/* no rejections: try to match the user */
665 			if (hostok)
666 				userok = !(strcmp(ruser,*user ? user : luser));
667 			break;
668 		}
669 		if (hostok && userok)
670 			return(0);
671 	}
672 	return (-1);
673 }
674 
675 /*
676  * Returns "true" if match, 0 if no match.
677  */
678 static int
__icheckhost(const struct sockaddr * raddr,socklen_t salen,const char * lhost)679 __icheckhost(const struct sockaddr *raddr, socklen_t salen, const char *lhost)
680 {
681 	struct sockaddr_in sin;
682 	struct sockaddr_in6 *sin6;
683 	struct addrinfo hints, *res, *r;
684 	int error;
685 	char h1[NI_MAXHOST], h2[NI_MAXHOST];
686 
687 	if (raddr->sa_family == AF_INET6) {
688 		sin6 = (struct sockaddr_in6 *)raddr;
689 		if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
690 			memset(&sin, 0, sizeof(sin));
691 			sin.sin_family = AF_INET;
692 			sin.sin_len = sizeof(struct sockaddr_in);
693 			memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr[12],
694 			       sizeof(sin.sin_addr));
695 			raddr = (struct sockaddr *)&sin;
696 			salen = sin.sin_len;
697 		}
698 	}
699 
700 	h1[0] = '\0';
701 	if (getnameinfo(raddr, salen, h1, sizeof(h1), NULL, 0,
702 			NI_NUMERICHOST) != 0)
703 		return (0);
704 
705 	/* Resolve laddr into sockaddr */
706 	memset(&hints, 0, sizeof(hints));
707 	hints.ai_family = raddr->sa_family;
708 	hints.ai_socktype = SOCK_DGRAM;	/*XXX dummy*/
709 	res = NULL;
710 	error = getaddrinfo(lhost, "0", &hints, &res);
711 	if (error)
712 		return (0);
713 
714 	for (r = res; r ; r = r->ai_next) {
715 		h2[0] = '\0';
716 		if (getnameinfo(r->ai_addr, r->ai_addrlen, h2, sizeof(h2),
717 				NULL, 0, NI_NUMERICHOST) != 0)
718 			continue;
719 		if (strcmp(h1, h2) == 0) {
720 			freeaddrinfo(res);
721 			return (1);
722 		}
723 	}
724 
725 	/* No match. */
726 	freeaddrinfo(res);
727 	return (0);
728 }
729