xref: /openbsd-src/usr.bin/ssh/ssh-keyscan.c (revision ae3cb403620ab940fbaabb3055fac045a63d56b7)
1 /* $OpenBSD: ssh-keyscan.c,v 1.116 2017/11/25 06:46:22 dtucker 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 <sys/types.h>
11 #include <sys/socket.h>
12 #include <sys/queue.h>
13 #include <sys/time.h>
14 #include <sys/resource.h>
15 
16 #include <openssl/bn.h>
17 
18 #include <errno.h>
19 #include <netdb.h>
20 #include <stdarg.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <signal.h>
24 #include <string.h>
25 #include <unistd.h>
26 
27 #include "xmalloc.h"
28 #include "ssh.h"
29 #include "sshbuf.h"
30 #include "sshkey.h"
31 #include "cipher.h"
32 #include "kex.h"
33 #include "compat.h"
34 #include "myproposal.h"
35 #include "packet.h"
36 #include "dispatch.h"
37 #include "log.h"
38 #include "atomicio.h"
39 #include "misc.h"
40 #include "hostfile.h"
41 #include "ssherr.h"
42 #include "ssh_api.h"
43 
44 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
45    Default value is AF_UNSPEC means both IPv4 and IPv6. */
46 int IPv4or6 = AF_UNSPEC;
47 
48 int ssh_port = SSH_DEFAULT_PORT;
49 
50 #define KT_DSA		(1)
51 #define KT_RSA		(1<<1)
52 #define KT_ECDSA	(1<<2)
53 #define KT_ED25519	(1<<3)
54 
55 #define KT_MIN		KT_DSA
56 #define KT_MAX		KT_ED25519
57 
58 int get_cert = 0;
59 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
60 
61 int hash_hosts = 0;		/* Hash hostname on output */
62 
63 #define MAXMAXFD 256
64 
65 /* The number of seconds after which to give up on a TCP connection */
66 int timeout = 5;
67 
68 int maxfd;
69 #define MAXCON (maxfd - 10)
70 
71 extern char *__progname;
72 fd_set *read_wait;
73 size_t read_wait_nfdset;
74 int ncon;
75 
76 /*
77  * Keep a connection structure for each file descriptor.  The state
78  * associated with file descriptor n is held in fdcon[n].
79  */
80 typedef struct Connection {
81 	u_char c_status;	/* State of connection on this file desc. */
82 #define CS_UNUSED 0		/* File descriptor unused */
83 #define CS_CON 1		/* Waiting to connect/read greeting */
84 #define CS_SIZE 2		/* Waiting to read initial packet size */
85 #define CS_KEYS 3		/* Waiting to read public key packet */
86 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
87 	int c_plen;		/* Packet length field for ssh packet */
88 	int c_len;		/* Total bytes which must be read. */
89 	int c_off;		/* Length of data read so far. */
90 	int c_keytype;		/* Only one of KT_* */
91 	sig_atomic_t c_done;	/* SSH2 done */
92 	char *c_namebase;	/* Address to free for c_name and c_namelist */
93 	char *c_name;		/* Hostname of connection for errors */
94 	char *c_namelist;	/* Pointer to other possible addresses */
95 	char *c_output_name;	/* Hostname of connection for output */
96 	char *c_data;		/* Data read from this fd */
97 	struct ssh *c_ssh;	/* SSH-connection */
98 	struct timeval c_tv;	/* Time at which connection gets aborted */
99 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
100 } con;
101 
102 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
103 con *fdcon;
104 
105 static void keyprint(con *c, struct sshkey *key);
106 
107 static int
108 fdlim_get(int hard)
109 {
110 	struct rlimit rlfd;
111 
112 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
113 		return (-1);
114 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
115 		return sysconf(_SC_OPEN_MAX);
116 	else
117 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
118 }
119 
120 static int
121 fdlim_set(int lim)
122 {
123 	struct rlimit rlfd;
124 
125 	if (lim <= 0)
126 		return (-1);
127 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
128 		return (-1);
129 	rlfd.rlim_cur = lim;
130 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
131 		return (-1);
132 	return (0);
133 }
134 
135 /*
136  * This is an strsep function that returns a null field for adjacent
137  * separators.  This is the same as the 4.4BSD strsep, but different from the
138  * one in the GNU libc.
139  */
140 static char *
141 xstrsep(char **str, const char *delim)
142 {
143 	char *s, *e;
144 
145 	if (!**str)
146 		return (NULL);
147 
148 	s = *str;
149 	e = s + strcspn(s, delim);
150 
151 	if (*e != '\0')
152 		*e++ = '\0';
153 	*str = e;
154 
155 	return (s);
156 }
157 
158 /*
159  * Get the next non-null token (like GNU strsep).  Strsep() will return a
160  * null token for two adjacent separators, so we may have to loop.
161  */
162 static char *
163 strnnsep(char **stringp, char *delim)
164 {
165 	char *tok;
166 
167 	do {
168 		tok = xstrsep(stringp, delim);
169 	} while (tok && *tok == '\0');
170 	return (tok);
171 }
172 
173 
174 static int
175 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
176 {
177 	con *c;
178 
179 	if ((c = ssh_get_app_data(ssh)) != NULL)
180 		keyprint(c, hostkey);
181 	/* always abort key exchange */
182 	return -1;
183 }
184 
185 static int
186 ssh2_capable(int remote_major, int remote_minor)
187 {
188 	switch (remote_major) {
189 	case 1:
190 		if (remote_minor == 99)
191 			return 1;
192 		break;
193 	case 2:
194 		return 1;
195 	default:
196 		break;
197 	}
198 	return 0;
199 }
200 
201 static void
202 keygrab_ssh2(con *c)
203 {
204 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
205 	int r;
206 
207 	switch (c->c_keytype) {
208 	case KT_DSA:
209 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
210 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
211 		break;
212 	case KT_RSA:
213 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
214 		    "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
215 		break;
216 	case KT_ED25519:
217 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
218 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
219 		break;
220 	case KT_ECDSA:
221 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
222 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
223 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
224 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
225 		    "ecdsa-sha2-nistp256,"
226 		    "ecdsa-sha2-nistp384,"
227 		    "ecdsa-sha2-nistp521";
228 		break;
229 	default:
230 		fatal("unknown key type %d", c->c_keytype);
231 		break;
232 	}
233 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
234 		free(c->c_ssh);
235 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
236 		exit(1);
237 	}
238 #ifdef WITH_OPENSSL
239 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
240 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
241 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
242 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
243 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
244 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
245 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
246 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
247 #endif
248 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
249 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
250 	/*
251 	 * do the key-exchange until an error occurs or until
252 	 * the key_print_wrapper() callback sets c_done.
253 	 */
254 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
255 }
256 
257 static void
258 keyprint_one(const char *host, struct sshkey *key)
259 {
260 	char *hostport;
261 	const char *known_host, *hashed;
262 
263 	hostport = put_host_port(host, ssh_port);
264 	lowercase(hostport);
265 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
266 		fatal("host_hash failed");
267 	known_host = hash_hosts ? hashed : hostport;
268 	if (!get_cert)
269 		fprintf(stdout, "%s ", known_host);
270 	sshkey_write(key, stdout);
271 	fputs("\n", stdout);
272 	free(hostport);
273 }
274 
275 static void
276 keyprint(con *c, struct sshkey *key)
277 {
278 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
279 	char *host, *ohosts;
280 
281 	if (key == NULL)
282 		return;
283 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
284 		keyprint_one(hosts, key);
285 		return;
286 	}
287 	ohosts = hosts = xstrdup(hosts);
288 	while ((host = strsep(&hosts, ",")) != NULL)
289 		keyprint_one(host, key);
290 	free(ohosts);
291 }
292 
293 static int
294 tcpconnect(char *host)
295 {
296 	struct addrinfo hints, *ai, *aitop;
297 	char strport[NI_MAXSERV];
298 	int gaierr, s = -1;
299 
300 	snprintf(strport, sizeof strport, "%d", ssh_port);
301 	memset(&hints, 0, sizeof(hints));
302 	hints.ai_family = IPv4or6;
303 	hints.ai_socktype = SOCK_STREAM;
304 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
305 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
306 		return -1;
307 	}
308 	for (ai = aitop; ai; ai = ai->ai_next) {
309 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
310 		if (s < 0) {
311 			error("socket: %s", strerror(errno));
312 			continue;
313 		}
314 		if (set_nonblock(s) == -1)
315 			fatal("%s: set_nonblock(%d)", __func__, s);
316 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
317 		    errno != EINPROGRESS)
318 			error("connect (`%s'): %s", host, strerror(errno));
319 		else
320 			break;
321 		close(s);
322 		s = -1;
323 	}
324 	freeaddrinfo(aitop);
325 	return s;
326 }
327 
328 static int
329 conalloc(char *iname, char *oname, int keytype)
330 {
331 	char *namebase, *name, *namelist;
332 	int s;
333 
334 	namebase = namelist = xstrdup(iname);
335 
336 	do {
337 		name = xstrsep(&namelist, ",");
338 		if (!name) {
339 			free(namebase);
340 			return (-1);
341 		}
342 	} while ((s = tcpconnect(name)) < 0);
343 
344 	if (s >= maxfd)
345 		fatal("conalloc: fdno %d too high", s);
346 	if (fdcon[s].c_status)
347 		fatal("conalloc: attempt to reuse fdno %d", s);
348 
349 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
350 	fdcon[s].c_fd = s;
351 	fdcon[s].c_status = CS_CON;
352 	fdcon[s].c_namebase = namebase;
353 	fdcon[s].c_name = name;
354 	fdcon[s].c_namelist = namelist;
355 	fdcon[s].c_output_name = xstrdup(oname);
356 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
357 	fdcon[s].c_len = 4;
358 	fdcon[s].c_off = 0;
359 	fdcon[s].c_keytype = keytype;
360 	monotime_tv(&fdcon[s].c_tv);
361 	fdcon[s].c_tv.tv_sec += timeout;
362 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
363 	FD_SET(s, read_wait);
364 	ncon++;
365 	return (s);
366 }
367 
368 static void
369 confree(int s)
370 {
371 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
372 		fatal("confree: attempt to free bad fdno %d", s);
373 	free(fdcon[s].c_namebase);
374 	free(fdcon[s].c_output_name);
375 	if (fdcon[s].c_status == CS_KEYS)
376 		free(fdcon[s].c_data);
377 	fdcon[s].c_status = CS_UNUSED;
378 	fdcon[s].c_keytype = 0;
379 	if (fdcon[s].c_ssh) {
380 		ssh_packet_close(fdcon[s].c_ssh);
381 		free(fdcon[s].c_ssh);
382 		fdcon[s].c_ssh = NULL;
383 	} else
384 		close(s);
385 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
386 	FD_CLR(s, read_wait);
387 	ncon--;
388 }
389 
390 static void
391 contouch(int s)
392 {
393 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
394 	monotime_tv(&fdcon[s].c_tv);
395 	fdcon[s].c_tv.tv_sec += timeout;
396 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
397 }
398 
399 static int
400 conrecycle(int s)
401 {
402 	con *c = &fdcon[s];
403 	int ret;
404 
405 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
406 	confree(s);
407 	return (ret);
408 }
409 
410 static void
411 congreet(int s)
412 {
413 	int n = 0, remote_major = 0, remote_minor = 0;
414 	char buf[256], *cp;
415 	char remote_version[sizeof buf];
416 	size_t bufsiz;
417 	con *c = &fdcon[s];
418 
419 	/* send client banner */
420 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
421 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
422 	if (n < 0 || (size_t)n >= sizeof(buf)) {
423 		error("snprintf: buffer too small");
424 		confree(s);
425 		return;
426 	}
427 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
428 		error("write (%s): %s", c->c_name, strerror(errno));
429 		confree(s);
430 		return;
431 	}
432 
433 	for (;;) {
434 		memset(buf, '\0', sizeof(buf));
435 		bufsiz = sizeof(buf);
436 		cp = buf;
437 		while (bufsiz-- &&
438 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
439 			if (*cp == '\r')
440 				*cp = '\n';
441 			cp++;
442 		}
443 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
444 			break;
445 	}
446 	if (n == 0) {
447 		switch (errno) {
448 		case EPIPE:
449 			error("%s: Connection closed by remote host", c->c_name);
450 			break;
451 		case ECONNREFUSED:
452 			break;
453 		default:
454 			error("read (%s): %s", c->c_name, strerror(errno));
455 			break;
456 		}
457 		conrecycle(s);
458 		return;
459 	}
460 	if (*cp != '\n' && *cp != '\r') {
461 		error("%s: bad greeting", c->c_name);
462 		confree(s);
463 		return;
464 	}
465 	*cp = '\0';
466 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
467 		fatal("ssh_packet_set_connection failed");
468 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
469 	ssh_set_app_data(c->c_ssh, c);	/* back link */
470 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
471 	    &remote_major, &remote_minor, remote_version) == 3)
472 		c->c_ssh->compat = compat_datafellows(remote_version);
473 	else
474 		c->c_ssh->compat = 0;
475 	if (!ssh2_capable(remote_major, remote_minor)) {
476 		debug("%s doesn't support ssh2", c->c_name);
477 		confree(s);
478 		return;
479 	}
480 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
481 	keygrab_ssh2(c);
482 	confree(s);
483 }
484 
485 static void
486 conread(int s)
487 {
488 	con *c = &fdcon[s];
489 	size_t n;
490 
491 	if (c->c_status == CS_CON) {
492 		congreet(s);
493 		return;
494 	}
495 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
496 	if (n == 0) {
497 		error("read (%s): %s", c->c_name, strerror(errno));
498 		confree(s);
499 		return;
500 	}
501 	c->c_off += n;
502 
503 	if (c->c_off == c->c_len)
504 		switch (c->c_status) {
505 		case CS_SIZE:
506 			c->c_plen = htonl(c->c_plen);
507 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
508 			c->c_off = 0;
509 			c->c_data = xmalloc(c->c_len);
510 			c->c_status = CS_KEYS;
511 			break;
512 		default:
513 			fatal("conread: invalid status %d", c->c_status);
514 			break;
515 		}
516 
517 	contouch(s);
518 }
519 
520 static void
521 conloop(void)
522 {
523 	struct timeval seltime, now;
524 	fd_set *r, *e;
525 	con *c;
526 	int i;
527 
528 	monotime_tv(&now);
529 	c = TAILQ_FIRST(&tq);
530 
531 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
532 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
533 		seltime = c->c_tv;
534 		seltime.tv_sec -= now.tv_sec;
535 		seltime.tv_usec -= now.tv_usec;
536 		if (seltime.tv_usec < 0) {
537 			seltime.tv_usec += 1000000;
538 			seltime.tv_sec--;
539 		}
540 	} else
541 		timerclear(&seltime);
542 
543 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
544 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
545 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
546 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
547 
548 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
549 	    (errno == EAGAIN || errno == EINTR))
550 		;
551 
552 	for (i = 0; i < maxfd; i++) {
553 		if (FD_ISSET(i, e)) {
554 			error("%s: exception!", fdcon[i].c_name);
555 			confree(i);
556 		} else if (FD_ISSET(i, r))
557 			conread(i);
558 	}
559 	free(r);
560 	free(e);
561 
562 	c = TAILQ_FIRST(&tq);
563 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
564 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
565 		int s = c->c_fd;
566 
567 		c = TAILQ_NEXT(c, c_link);
568 		conrecycle(s);
569 	}
570 }
571 
572 static void
573 do_host(char *host)
574 {
575 	char *name = strnnsep(&host, " \t\n");
576 	int j;
577 
578 	if (name == NULL)
579 		return;
580 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
581 		if (get_keytypes & j) {
582 			while (ncon >= MAXCON)
583 				conloop();
584 			conalloc(name, *host ? host : name, j);
585 		}
586 	}
587 }
588 
589 void
590 fatal(const char *fmt,...)
591 {
592 	va_list args;
593 
594 	va_start(args, fmt);
595 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
596 	va_end(args);
597 	exit(255);
598 }
599 
600 static void
601 usage(void)
602 {
603 	fprintf(stderr,
604 	    "usage: %s [-46cHv] [-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
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 	ssh_malloc_init();	/* must be called before any mallocs */
623 	TAILQ_INIT(&tq);
624 
625 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
626 	sanitise_stdfd();
627 
628 	if (argc <= 1)
629 		usage();
630 
631 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
632 		switch (opt) {
633 		case 'H':
634 			hash_hosts = 1;
635 			break;
636 		case 'c':
637 			get_cert = 1;
638 			break;
639 		case 'p':
640 			ssh_port = a2port(optarg);
641 			if (ssh_port <= 0) {
642 				fprintf(stderr, "Bad port '%s'\n", optarg);
643 				exit(1);
644 			}
645 			break;
646 		case 'T':
647 			timeout = convtime(optarg);
648 			if (timeout == -1 || timeout == 0) {
649 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
650 				usage();
651 			}
652 			break;
653 		case 'v':
654 			if (!debug_flag) {
655 				debug_flag = 1;
656 				log_level = SYSLOG_LEVEL_DEBUG1;
657 			}
658 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
659 				log_level++;
660 			else
661 				fatal("Too high debugging level.");
662 			break;
663 		case 'f':
664 			if (strcmp(optarg, "-") == 0)
665 				optarg = NULL;
666 			argv[fopt_count++] = optarg;
667 			break;
668 		case 't':
669 			get_keytypes = 0;
670 			tname = strtok(optarg, ",");
671 			while (tname) {
672 				int type = sshkey_type_from_name(tname);
673 
674 				switch (type) {
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_ED25519:
685 					get_keytypes |= KT_ED25519;
686 					break;
687 				case KEY_UNSPEC:
688 				default:
689 					fatal("Unknown key type \"%s\"", tname);
690 				}
691 				tname = strtok(NULL, ",");
692 			}
693 			break;
694 		case '4':
695 			IPv4or6 = AF_INET;
696 			break;
697 		case '6':
698 			IPv4or6 = AF_INET6;
699 			break;
700 		case '?':
701 		default:
702 			usage();
703 		}
704 	}
705 	if (optind == argc && !fopt_count)
706 		usage();
707 
708 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
709 
710 	maxfd = fdlim_get(1);
711 	if (maxfd < 0)
712 		fatal("%s: fdlim_get: bad value", __progname);
713 	if (maxfd > MAXMAXFD)
714 		maxfd = MAXMAXFD;
715 	if (MAXCON <= 0)
716 		fatal("%s: not enough file descriptors", __progname);
717 	if (maxfd > fdlim_get(0))
718 		fdlim_set(maxfd);
719 	fdcon = xcalloc(maxfd, sizeof(con));
720 
721 	read_wait_nfdset = howmany(maxfd, NFDBITS);
722 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
723 
724 	for (j = 0; j < fopt_count; j++) {
725 		if (argv[j] == NULL)
726 			fp = stdin;
727 		else if ((fp = fopen(argv[j], "r")) == NULL)
728 			fatal("%s: %s: %s", __progname, argv[j],
729 			    strerror(errno));
730 		linenum = 0;
731 
732 		while (read_keyfile_line(fp,
733 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
734 		    &linenum) != -1) {
735 			/* Chomp off trailing whitespace and comments */
736 			if ((cp = strchr(line, '#')) == NULL)
737 				cp = line + strlen(line) - 1;
738 			while (cp >= line) {
739 				if (*cp == ' ' || *cp == '\t' ||
740 				    *cp == '\n' || *cp == '#')
741 					*cp-- = '\0';
742 				else
743 					break;
744 			}
745 
746 			/* Skip empty lines */
747 			if (*line == '\0')
748 				continue;
749 
750 			do_host(line);
751 		}
752 
753 		if (ferror(fp))
754 			fatal("%s: %s: %s", __progname, argv[j],
755 			    strerror(errno));
756 
757 		fclose(fp);
758 	}
759 
760 	while (optind < argc)
761 		do_host(argv[optind++]);
762 
763 	while (ncon > 0)
764 		conloop();
765 
766 	return (0);
767 }
768