• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /* $OpenBSD: ssh-keyscan.c,v 1.85 2011/03/15 10:36:02 okan Exp $ */
2 /*
3  * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
4  *
5  * Modification and redistribution in source and binary forms is
6  * permitted provided that due credit is given to the author and the
7  * OpenBSD project by leaving this copyright notice intact.
8  */
9 
10 #include "includes.h"
11 
12 #include "openbsd-compat/sys-queue.h"
13 #include <sys/resource.h>
14 #ifdef HAVE_SYS_TIME_H
15 # include <sys/time.h>
16 #endif
17 
18 #include <netinet/in.h>
19 #include <arpa/inet.h>
20 
21 #include <openssl/bn.h>
22 
23 #include <netdb.h>
24 #include <errno.h>
25 #include <setjmp.h>
26 #include <stdarg.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <signal.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "xmalloc.h"
34 #include "ssh.h"
35 #include "ssh1.h"
36 #include "buffer.h"
37 #include "key.h"
38 #include "cipher.h"
39 #include "kex.h"
40 #include "compat.h"
41 #include "myproposal.h"
42 #include "packet.h"
43 #include "dispatch.h"
44 #include "log.h"
45 #include "atomicio.h"
46 #include "misc.h"
47 #include "hostfile.h"
48 
49 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
50    Default value is AF_UNSPEC means both IPv4 and IPv6. */
51 int IPv4or6 = AF_UNSPEC;
52 
53 int ssh_port = SSH_DEFAULT_PORT;
54 
55 #define KT_RSA1		1
56 #define KT_DSA		2
57 #define KT_RSA		4
58 #define KT_ECDSA	8
59 
60 int get_keytypes = KT_RSA;	/* Get only RSA keys by default */
61 
62 int hash_hosts = 0;		/* Hash hostname on output */
63 
64 #define MAXMAXFD 256
65 
66 /* The number of seconds after which to give up on a TCP connection */
67 int timeout = 5;
68 
69 int maxfd;
70 #define MAXCON (maxfd - 10)
71 
72 extern char *__progname;
73 fd_set *read_wait;
74 size_t read_wait_nfdset;
75 int ncon;
76 int nonfatal_fatal = 0;
77 jmp_buf kexjmp;
78 Key *kexjmp_key;
79 
80 /*
81  * Keep a connection structure for each file descriptor.  The state
82  * associated with file descriptor n is held in fdcon[n].
83  */
84 typedef struct Connection {
85 	u_char c_status;	/* State of connection on this file desc. */
86 #define CS_UNUSED 0		/* File descriptor unused */
87 #define CS_CON 1		/* Waiting to connect/read greeting */
88 #define CS_SIZE 2		/* Waiting to read initial packet size */
89 #define CS_KEYS 3		/* Waiting to read public key packet */
90 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
91 	int c_plen;		/* Packet length field for ssh packet */
92 	int c_len;		/* Total bytes which must be read. */
93 	int c_off;		/* Length of data read so far. */
94 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
95 	char *c_namebase;	/* Address to free for c_name and c_namelist */
96 	char *c_name;		/* Hostname of connection for errors */
97 	char *c_namelist;	/* Pointer to other possible addresses */
98 	char *c_output_name;	/* Hostname of connection for output */
99 	char *c_data;		/* Data read from this fd */
100 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
101 	struct timeval c_tv;	/* Time at which connection gets aborted */
102 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
103 } con;
104 
105 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
106 con *fdcon;
107 
108 static int
fdlim_get(int hard)109 fdlim_get(int hard)
110 {
111 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
112 	struct rlimit rlfd;
113 
114 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
115 		return (-1);
116 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
117 		return SSH_SYSFDMAX;
118 	else
119 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
120 #else
121 	return SSH_SYSFDMAX;
122 #endif
123 }
124 
125 static int
fdlim_set(int lim)126 fdlim_set(int lim)
127 {
128 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
129 	struct rlimit rlfd;
130 #endif
131 
132 	if (lim <= 0)
133 		return (-1);
134 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
135 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
136 		return (-1);
137 	rlfd.rlim_cur = lim;
138 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
139 		return (-1);
140 #elif defined (HAVE_SETDTABLESIZE)
141 	setdtablesize(lim);
142 #endif
143 	return (0);
144 }
145 
146 /*
147  * This is an strsep function that returns a null field for adjacent
148  * separators.  This is the same as the 4.4BSD strsep, but different from the
149  * one in the GNU libc.
150  */
151 static char *
xstrsep(char ** str,const char * delim)152 xstrsep(char **str, const char *delim)
153 {
154 	char *s, *e;
155 
156 	if (!**str)
157 		return (NULL);
158 
159 	s = *str;
160 	e = s + strcspn(s, delim);
161 
162 	if (*e != '\0')
163 		*e++ = '\0';
164 	*str = e;
165 
166 	return (s);
167 }
168 
169 /*
170  * Get the next non-null token (like GNU strsep).  Strsep() will return a
171  * null token for two adjacent separators, so we may have to loop.
172  */
173 static char *
strnnsep(char ** stringp,char * delim)174 strnnsep(char **stringp, char *delim)
175 {
176 	char *tok;
177 
178 	do {
179 		tok = xstrsep(stringp, delim);
180 	} while (tok && *tok == '\0');
181 	return (tok);
182 }
183 
184 static Key *
keygrab_ssh1(con * c)185 keygrab_ssh1(con *c)
186 {
187 	static Key *rsa;
188 	static Buffer msg;
189 
190 	if (rsa == NULL) {
191 		buffer_init(&msg);
192 		rsa = key_new(KEY_RSA1);
193 	}
194 	buffer_append(&msg, c->c_data, c->c_plen);
195 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
196 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
197 		error("%s: invalid packet type", c->c_name);
198 		buffer_clear(&msg);
199 		return NULL;
200 	}
201 	buffer_consume(&msg, 8);		/* cookie */
202 
203 	/* server key */
204 	(void) buffer_get_int(&msg);
205 	buffer_get_bignum(&msg, rsa->rsa->e);
206 	buffer_get_bignum(&msg, rsa->rsa->n);
207 
208 	/* host key */
209 	(void) buffer_get_int(&msg);
210 	buffer_get_bignum(&msg, rsa->rsa->e);
211 	buffer_get_bignum(&msg, rsa->rsa->n);
212 
213 	buffer_clear(&msg);
214 
215 	return (rsa);
216 }
217 
218 static int
hostjump(Key * hostkey)219 hostjump(Key *hostkey)
220 {
221 	kexjmp_key = hostkey;
222 	longjmp(kexjmp, 1);
223 }
224 
225 static int
ssh2_capable(int remote_major,int remote_minor)226 ssh2_capable(int remote_major, int remote_minor)
227 {
228 	switch (remote_major) {
229 	case 1:
230 		if (remote_minor == 99)
231 			return 1;
232 		break;
233 	case 2:
234 		return 1;
235 	default:
236 		break;
237 	}
238 	return 0;
239 }
240 
241 static Key *
keygrab_ssh2(con * c)242 keygrab_ssh2(con *c)
243 {
244 	int j;
245 
246 	packet_set_connection(c->c_fd, c->c_fd);
247 	enable_compat20();
248 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
249 	    "ssh-dss" : (c->c_keytype == KT_RSA ? "ssh-rsa" :
250 	    "ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521");
251 	c->c_kex = kex_setup(myproposal);
252 	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
253 	c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
254 	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
255 	c->c_kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
256 	c->c_kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
257 	c->c_kex->verify_host_key = hostjump;
258 
259 	if (!(j = setjmp(kexjmp))) {
260 		nonfatal_fatal = 1;
261 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
262 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
263 		exit(1);
264 	}
265 	nonfatal_fatal = 0;
266 	xfree(c->c_kex);
267 	c->c_kex = NULL;
268 	packet_close();
269 
270 	return j < 0? NULL : kexjmp_key;
271 }
272 
273 static void
keyprint(con * c,Key * key)274 keyprint(con *c, Key *key)
275 {
276 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
277 
278 	if (!key)
279 		return;
280 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
281 		fatal("host_hash failed");
282 
283 	fprintf(stdout, "%s ", host);
284 	key_write(key, stdout);
285 	fputs("\n", stdout);
286 }
287 
288 static int
tcpconnect(char * host)289 tcpconnect(char *host)
290 {
291 	struct addrinfo hints, *ai, *aitop;
292 	char strport[NI_MAXSERV];
293 	int gaierr, s = -1;
294 
295 	snprintf(strport, sizeof strport, "%d", ssh_port);
296 	memset(&hints, 0, sizeof(hints));
297 	hints.ai_family = IPv4or6;
298 	hints.ai_socktype = SOCK_STREAM;
299 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
300 		fatal("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
301 	for (ai = aitop; ai; ai = ai->ai_next) {
302 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
303 		if (s < 0) {
304 			error("socket: %s", strerror(errno));
305 			continue;
306 		}
307 		if (set_nonblock(s) == -1)
308 			fatal("%s: set_nonblock(%d)", __func__, s);
309 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
310 		    errno != EINPROGRESS)
311 			error("connect (`%s'): %s", host, strerror(errno));
312 		else
313 			break;
314 		close(s);
315 		s = -1;
316 	}
317 	freeaddrinfo(aitop);
318 	return s;
319 }
320 
321 static int
conalloc(char * iname,char * oname,int keytype)322 conalloc(char *iname, char *oname, int keytype)
323 {
324 	char *namebase, *name, *namelist;
325 	int s;
326 
327 	namebase = namelist = xstrdup(iname);
328 
329 	do {
330 		name = xstrsep(&namelist, ",");
331 		if (!name) {
332 			xfree(namebase);
333 			return (-1);
334 		}
335 	} while ((s = tcpconnect(name)) < 0);
336 
337 	if (s >= maxfd)
338 		fatal("conalloc: fdno %d too high", s);
339 	if (fdcon[s].c_status)
340 		fatal("conalloc: attempt to reuse fdno %d", s);
341 
342 	fdcon[s].c_fd = s;
343 	fdcon[s].c_status = CS_CON;
344 	fdcon[s].c_namebase = namebase;
345 	fdcon[s].c_name = name;
346 	fdcon[s].c_namelist = namelist;
347 	fdcon[s].c_output_name = xstrdup(oname);
348 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
349 	fdcon[s].c_len = 4;
350 	fdcon[s].c_off = 0;
351 	fdcon[s].c_keytype = keytype;
352 	gettimeofday(&fdcon[s].c_tv, NULL);
353 	fdcon[s].c_tv.tv_sec += timeout;
354 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
355 	FD_SET(s, read_wait);
356 	ncon++;
357 	return (s);
358 }
359 
360 static void
confree(int s)361 confree(int s)
362 {
363 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
364 		fatal("confree: attempt to free bad fdno %d", s);
365 	close(s);
366 	xfree(fdcon[s].c_namebase);
367 	xfree(fdcon[s].c_output_name);
368 	if (fdcon[s].c_status == CS_KEYS)
369 		xfree(fdcon[s].c_data);
370 	fdcon[s].c_status = CS_UNUSED;
371 	fdcon[s].c_keytype = 0;
372 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
373 	FD_CLR(s, read_wait);
374 	ncon--;
375 }
376 
377 static void
contouch(int s)378 contouch(int s)
379 {
380 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
381 	gettimeofday(&fdcon[s].c_tv, NULL);
382 	fdcon[s].c_tv.tv_sec += timeout;
383 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
384 }
385 
386 static int
conrecycle(int s)387 conrecycle(int s)
388 {
389 	con *c = &fdcon[s];
390 	int ret;
391 
392 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
393 	confree(s);
394 	return (ret);
395 }
396 
397 static void
congreet(int s)398 congreet(int s)
399 {
400 	int n = 0, remote_major = 0, remote_minor = 0;
401 	char buf[256], *cp;
402 	char remote_version[sizeof buf];
403 	size_t bufsiz;
404 	con *c = &fdcon[s];
405 
406 	for (;;) {
407 		memset(buf, '\0', sizeof(buf));
408 		bufsiz = sizeof(buf);
409 		cp = buf;
410 		while (bufsiz-- &&
411 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
412 			if (*cp == '\r')
413 				*cp = '\n';
414 			cp++;
415 		}
416 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
417 			break;
418 	}
419 	if (n == 0) {
420 		switch (errno) {
421 		case EPIPE:
422 			error("%s: Connection closed by remote host", c->c_name);
423 			break;
424 		case ECONNREFUSED:
425 			break;
426 		default:
427 			error("read (%s): %s", c->c_name, strerror(errno));
428 			break;
429 		}
430 		conrecycle(s);
431 		return;
432 	}
433 	if (*cp != '\n' && *cp != '\r') {
434 		error("%s: bad greeting", c->c_name);
435 		confree(s);
436 		return;
437 	}
438 	*cp = '\0';
439 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
440 	    &remote_major, &remote_minor, remote_version) == 3)
441 		compat_datafellows(remote_version);
442 	else
443 		datafellows = 0;
444 	if (c->c_keytype != KT_RSA1) {
445 		if (!ssh2_capable(remote_major, remote_minor)) {
446 			debug("%s doesn't support ssh2", c->c_name);
447 			confree(s);
448 			return;
449 		}
450 	} else if (remote_major != 1) {
451 		debug("%s doesn't support ssh1", c->c_name);
452 		confree(s);
453 		return;
454 	}
455 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
456 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
457 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
458 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
459 	if (n < 0 || (size_t)n >= sizeof(buf)) {
460 		error("snprintf: buffer too small");
461 		confree(s);
462 		return;
463 	}
464 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
465 		error("write (%s): %s", c->c_name, strerror(errno));
466 		confree(s);
467 		return;
468 	}
469 	if (c->c_keytype != KT_RSA1) {
470 		keyprint(c, keygrab_ssh2(c));
471 		confree(s);
472 		return;
473 	}
474 	c->c_status = CS_SIZE;
475 	contouch(s);
476 }
477 
478 static void
conread(int s)479 conread(int s)
480 {
481 	con *c = &fdcon[s];
482 	size_t n;
483 
484 	if (c->c_status == CS_CON) {
485 		congreet(s);
486 		return;
487 	}
488 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
489 	if (n == 0) {
490 		error("read (%s): %s", c->c_name, strerror(errno));
491 		confree(s);
492 		return;
493 	}
494 	c->c_off += n;
495 
496 	if (c->c_off == c->c_len)
497 		switch (c->c_status) {
498 		case CS_SIZE:
499 			c->c_plen = htonl(c->c_plen);
500 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
501 			c->c_off = 0;
502 			c->c_data = xmalloc(c->c_len);
503 			c->c_status = CS_KEYS;
504 			break;
505 		case CS_KEYS:
506 			keyprint(c, keygrab_ssh1(c));
507 			confree(s);
508 			return;
509 		default:
510 			fatal("conread: invalid status %d", c->c_status);
511 			break;
512 		}
513 
514 	contouch(s);
515 }
516 
517 static void
conloop(void)518 conloop(void)
519 {
520 	struct timeval seltime, now;
521 	fd_set *r, *e;
522 	con *c;
523 	int i;
524 
525 	gettimeofday(&now, NULL);
526 	c = TAILQ_FIRST(&tq);
527 
528 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
529 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
530 		seltime = c->c_tv;
531 		seltime.tv_sec -= now.tv_sec;
532 		seltime.tv_usec -= now.tv_usec;
533 		if (seltime.tv_usec < 0) {
534 			seltime.tv_usec += 1000000;
535 			seltime.tv_sec--;
536 		}
537 	} else
538 		timerclear(&seltime);
539 
540 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
541 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
542 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
543 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
544 
545 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
546 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
547 		;
548 
549 	for (i = 0; i < maxfd; i++) {
550 		if (FD_ISSET(i, e)) {
551 			error("%s: exception!", fdcon[i].c_name);
552 			confree(i);
553 		} else if (FD_ISSET(i, r))
554 			conread(i);
555 	}
556 	xfree(r);
557 	xfree(e);
558 
559 	c = TAILQ_FIRST(&tq);
560 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
561 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
562 		int s = c->c_fd;
563 
564 		c = TAILQ_NEXT(c, c_link);
565 		conrecycle(s);
566 	}
567 }
568 
569 static void
do_host(char * host)570 do_host(char *host)
571 {
572 	char *name = strnnsep(&host, " \t\n");
573 	int j;
574 
575 	if (name == NULL)
576 		return;
577 	for (j = KT_RSA1; j <= KT_ECDSA; j *= 2) {
578 		if (get_keytypes & j) {
579 			while (ncon >= MAXCON)
580 				conloop();
581 			conalloc(name, *host ? host : name, j);
582 		}
583 	}
584 }
585 
586 void
fatal(const char * fmt,...)587 fatal(const char *fmt,...)
588 {
589 	va_list args;
590 
591 	va_start(args, fmt);
592 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
593 	va_end(args);
594 	if (nonfatal_fatal)
595 		longjmp(kexjmp, -1);
596 	else
597 		exit(255);
598 }
599 
600 static void
usage(void)601 usage(void)
602 {
603 	fprintf(stderr,
604 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
605 	    "\t\t   [host | addrlist namelist] ...\n",
606 	    __progname);
607 	exit(1);
608 }
609 
610 int
main(int argc,char ** argv)611 main(int argc, char **argv)
612 {
613 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
614 	int opt, fopt_count = 0, j;
615 	char *tname, *cp, line[NI_MAXHOST];
616 	FILE *fp;
617 	u_long linenum;
618 
619 	extern int optind;
620 	extern char *optarg;
621 
622 	__progname = ssh_get_progname(argv[0]);
623 	seed_rng();
624 	TAILQ_INIT(&tq);
625 
626 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
627 	sanitise_stdfd();
628 
629 	if (argc <= 1)
630 		usage();
631 
632 	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
633 		switch (opt) {
634 		case 'H':
635 			hash_hosts = 1;
636 			break;
637 		case 'p':
638 			ssh_port = a2port(optarg);
639 			if (ssh_port <= 0) {
640 				fprintf(stderr, "Bad port '%s'\n", optarg);
641 				exit(1);
642 			}
643 			break;
644 		case 'T':
645 			timeout = convtime(optarg);
646 			if (timeout == -1 || timeout == 0) {
647 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
648 				usage();
649 			}
650 			break;
651 		case 'v':
652 			if (!debug_flag) {
653 				debug_flag = 1;
654 				log_level = SYSLOG_LEVEL_DEBUG1;
655 			}
656 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
657 				log_level++;
658 			else
659 				fatal("Too high debugging level.");
660 			break;
661 		case 'f':
662 			if (strcmp(optarg, "-") == 0)
663 				optarg = NULL;
664 			argv[fopt_count++] = optarg;
665 			break;
666 		case 't':
667 			get_keytypes = 0;
668 			tname = strtok(optarg, ",");
669 			while (tname) {
670 				int type = key_type_from_name(tname);
671 				switch (type) {
672 				case KEY_RSA1:
673 					get_keytypes |= KT_RSA1;
674 					break;
675 				case KEY_DSA:
676 					get_keytypes |= KT_DSA;
677 					break;
678 				case KEY_ECDSA:
679 					get_keytypes |= KT_ECDSA;
680 					break;
681 				case KEY_RSA:
682 					get_keytypes |= KT_RSA;
683 					break;
684 				case KEY_UNSPEC:
685 					fatal("unknown key type %s", tname);
686 				}
687 				tname = strtok(NULL, ",");
688 			}
689 			break;
690 		case '4':
691 			IPv4or6 = AF_INET;
692 			break;
693 		case '6':
694 			IPv4or6 = AF_INET6;
695 			break;
696 		case '?':
697 		default:
698 			usage();
699 		}
700 	}
701 	if (optind == argc && !fopt_count)
702 		usage();
703 
704 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
705 
706 	maxfd = fdlim_get(1);
707 	if (maxfd < 0)
708 		fatal("%s: fdlim_get: bad value", __progname);
709 	if (maxfd > MAXMAXFD)
710 		maxfd = MAXMAXFD;
711 	if (MAXCON <= 0)
712 		fatal("%s: not enough file descriptors", __progname);
713 	if (maxfd > fdlim_get(0))
714 		fdlim_set(maxfd);
715 	fdcon = xcalloc(maxfd, sizeof(con));
716 
717 	read_wait_nfdset = howmany(maxfd, NFDBITS);
718 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
719 
720 	for (j = 0; j < fopt_count; j++) {
721 		if (argv[j] == NULL)
722 			fp = stdin;
723 		else if ((fp = fopen(argv[j], "r")) == NULL)
724 			fatal("%s: %s: %s", __progname, argv[j],
725 			    strerror(errno));
726 		linenum = 0;
727 
728 		while (read_keyfile_line(fp,
729 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
730 		    &linenum) != -1) {
731 			/* Chomp off trailing whitespace and comments */
732 			if ((cp = strchr(line, '#')) == NULL)
733 				cp = line + strlen(line) - 1;
734 			while (cp >= line) {
735 				if (*cp == ' ' || *cp == '\t' ||
736 				    *cp == '\n' || *cp == '#')
737 					*cp-- = '\0';
738 				else
739 					break;
740 			}
741 
742 			/* Skip empty lines */
743 			if (*line == '\0')
744 				continue;
745 
746 			do_host(line);
747 		}
748 
749 		if (ferror(fp))
750 			fatal("%s: %s: %s", __progname, argv[j],
751 			    strerror(errno));
752 
753 		fclose(fp);
754 	}
755 
756 	while (optind < argc)
757 		do_host(argv[optind++]);
758 
759 	while (ncon > 0)
760 		conloop();
761 
762 	return (0);
763 }
764