xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision 926ce35a7e33457153b56be1ba51a31aea674000) 
1 /* $OpenBSD: ssh-keyscan.c,v 1.120 2018/06/06 18:29:18 markus 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 <sys/types.h>
13 #include "openbsd-compat/sys-queue.h"
14 #include <sys/resource.h>
15 #ifdef HAVE_SYS_TIME_H
16 # include <sys/time.h>
17 #endif
18 
19 #include <netinet/in.h>
20 #include <arpa/inet.h>
21 
22 #include <openssl/bn.h>
23 
24 #include <netdb.h>
25 #include <errno.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 "sshbuf.h"
36 #include "sshkey.h"
37 #include "cipher.h"
38 #include "kex.h"
39 #include "compat.h"
40 #include "myproposal.h"
41 #include "packet.h"
42 #include "dispatch.h"
43 #include "log.h"
44 #include "atomicio.h"
45 #include "misc.h"
46 #include "hostfile.h"
47 #include "ssherr.h"
48 #include "ssh_api.h"
49 #include "dns.h"
50 
51 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
52    Default value is AF_UNSPEC means both IPv4 and IPv6. */
53 int IPv4or6 = AF_UNSPEC;
54 
55 int ssh_port = SSH_DEFAULT_PORT;
56 
57 #define KT_DSA		(1)
58 #define KT_RSA		(1<<1)
59 #define KT_ECDSA	(1<<2)
60 #define KT_ED25519	(1<<3)
61 #define KT_XMSS		(1<<4)
62 
63 #define KT_MIN		KT_DSA
64 #define KT_MAX		KT_XMSS
65 
66 int get_cert = 0;
67 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
68 
69 int hash_hosts = 0;		/* Hash hostname on output */
70 
71 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
72 
73 #define MAXMAXFD 256
74 
75 /* The number of seconds after which to give up on a TCP connection */
76 int timeout = 5;
77 
78 int maxfd;
79 #define MAXCON (maxfd - 10)
80 
81 extern char *__progname;
82 fd_set *read_wait;
83 size_t read_wait_nfdset;
84 int ncon;
85 
86 struct ssh *active_state = NULL; /* XXX needed for linking */
87 
88 /*
89  * Keep a connection structure for each file descriptor.  The state
90  * associated with file descriptor n is held in fdcon[n].
91  */
92 typedef struct Connection {
93 	u_char c_status;	/* State of connection on this file desc. */
94 #define CS_UNUSED 0		/* File descriptor unused */
95 #define CS_CON 1		/* Waiting to connect/read greeting */
96 #define CS_SIZE 2		/* Waiting to read initial packet size */
97 #define CS_KEYS 3		/* Waiting to read public key packet */
98 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
99 	int c_plen;		/* Packet length field for ssh packet */
100 	int c_len;		/* Total bytes which must be read. */
101 	int c_off;		/* Length of data read so far. */
102 	int c_keytype;		/* Only one of KT_* */
103 	sig_atomic_t c_done;	/* SSH2 done */
104 	char *c_namebase;	/* Address to free for c_name and c_namelist */
105 	char *c_name;		/* Hostname of connection for errors */
106 	char *c_namelist;	/* Pointer to other possible addresses */
107 	char *c_output_name;	/* Hostname of connection for output */
108 	char *c_data;		/* Data read from this fd */
109 	struct ssh *c_ssh;	/* SSH-connection */
110 	struct timeval c_tv;	/* Time at which connection gets aborted */
111 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
112 } con;
113 
114 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
115 con *fdcon;
116 
117 static void keyprint(con *c, struct sshkey *key);
118 
119 static int
120 fdlim_get(int hard)
121 {
122 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
123 	struct rlimit rlfd;
124 
125 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
126 		return (-1);
127 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
128 		return SSH_SYSFDMAX;
129 	else
130 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
131 #else
132 	return SSH_SYSFDMAX;
133 #endif
134 }
135 
136 static int
137 fdlim_set(int lim)
138 {
139 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
140 	struct rlimit rlfd;
141 #endif
142 
143 	if (lim <= 0)
144 		return (-1);
145 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
146 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
147 		return (-1);
148 	rlfd.rlim_cur = lim;
149 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
150 		return (-1);
151 #elif defined (HAVE_SETDTABLESIZE)
152 	setdtablesize(lim);
153 #endif
154 	return (0);
155 }
156 
157 /*
158  * This is an strsep function that returns a null field for adjacent
159  * separators.  This is the same as the 4.4BSD strsep, but different from the
160  * one in the GNU libc.
161  */
162 static char *
163 xstrsep(char **str, const char *delim)
164 {
165 	char *s, *e;
166 
167 	if (!**str)
168 		return (NULL);
169 
170 	s = *str;
171 	e = s + strcspn(s, delim);
172 
173 	if (*e != '\0')
174 		*e++ = '\0';
175 	*str = e;
176 
177 	return (s);
178 }
179 
180 /*
181  * Get the next non-null token (like GNU strsep).  Strsep() will return a
182  * null token for two adjacent separators, so we may have to loop.
183  */
184 static char *
185 strnnsep(char **stringp, char *delim)
186 {
187 	char *tok;
188 
189 	do {
190 		tok = xstrsep(stringp, delim);
191 	} while (tok && *tok == '\0');
192 	return (tok);
193 }
194 
195 
196 static int
197 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
198 {
199 	con *c;
200 
201 	if ((c = ssh_get_app_data(ssh)) != NULL)
202 		keyprint(c, hostkey);
203 	/* always abort key exchange */
204 	return -1;
205 }
206 
207 static int
208 ssh2_capable(int remote_major, int remote_minor)
209 {
210 	switch (remote_major) {
211 	case 1:
212 		if (remote_minor == 99)
213 			return 1;
214 		break;
215 	case 2:
216 		return 1;
217 	default:
218 		break;
219 	}
220 	return 0;
221 }
222 
223 static void
224 keygrab_ssh2(con *c)
225 {
226 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
227 	int r;
228 
229 	switch (c->c_keytype) {
230 	case KT_DSA:
231 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
232 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
233 		break;
234 	case KT_RSA:
235 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
236 		    "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
237 		break;
238 	case KT_ED25519:
239 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
240 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
241 		break;
242 	case KT_XMSS:
243 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
244 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
245 		break;
246 	case KT_ECDSA:
247 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
248 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
249 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
250 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
251 		    "ecdsa-sha2-nistp256,"
252 		    "ecdsa-sha2-nistp384,"
253 		    "ecdsa-sha2-nistp521";
254 		break;
255 	default:
256 		fatal("unknown key type %d", c->c_keytype);
257 		break;
258 	}
259 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
260 		free(c->c_ssh);
261 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
262 		exit(1);
263 	}
264 #ifdef WITH_OPENSSL
265 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
266 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
267 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
268 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
269 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
270 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
271 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
272 # ifdef OPENSSL_HAS_ECC
273 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
274 # endif
275 #endif
276 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
277 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
278 	/*
279 	 * do the key-exchange until an error occurs or until
280 	 * the key_print_wrapper() callback sets c_done.
281 	 */
282 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
283 }
284 
285 static void
286 keyprint_one(const char *host, struct sshkey *key)
287 {
288 	char *hostport;
289 	const char *known_host, *hashed;
290 
291 	if (print_sshfp) {
292 		export_dns_rr(host, key, stdout, 0);
293 		return;
294 	}
295 
296 	hostport = put_host_port(host, ssh_port);
297 	lowercase(hostport);
298 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
299 		fatal("host_hash failed");
300 	known_host = hash_hosts ? hashed : hostport;
301 	if (!get_cert)
302 		fprintf(stdout, "%s ", known_host);
303 	sshkey_write(key, stdout);
304 	fputs("\n", stdout);
305 	free(hostport);
306 }
307 
308 static void
309 keyprint(con *c, struct sshkey *key)
310 {
311 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
312 	char *host, *ohosts;
313 
314 	if (key == NULL)
315 		return;
316 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
317 		keyprint_one(hosts, key);
318 		return;
319 	}
320 	ohosts = hosts = xstrdup(hosts);
321 	while ((host = strsep(&hosts, ",")) != NULL)
322 		keyprint_one(host, key);
323 	free(ohosts);
324 }
325 
326 static int
327 tcpconnect(char *host)
328 {
329 	struct addrinfo hints, *ai, *aitop;
330 	char strport[NI_MAXSERV];
331 	int gaierr, s = -1;
332 
333 	snprintf(strport, sizeof strport, "%d", ssh_port);
334 	memset(&hints, 0, sizeof(hints));
335 	hints.ai_family = IPv4or6;
336 	hints.ai_socktype = SOCK_STREAM;
337 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
338 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
339 		return -1;
340 	}
341 	for (ai = aitop; ai; ai = ai->ai_next) {
342 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
343 		if (s < 0) {
344 			error("socket: %s", strerror(errno));
345 			continue;
346 		}
347 		if (set_nonblock(s) == -1)
348 			fatal("%s: set_nonblock(%d)", __func__, s);
349 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
350 		    errno != EINPROGRESS)
351 			error("connect (`%s'): %s", host, strerror(errno));
352 		else
353 			break;
354 		close(s);
355 		s = -1;
356 	}
357 	freeaddrinfo(aitop);
358 	return s;
359 }
360 
361 static int
362 conalloc(char *iname, char *oname, int keytype)
363 {
364 	char *namebase, *name, *namelist;
365 	int s;
366 
367 	namebase = namelist = xstrdup(iname);
368 
369 	do {
370 		name = xstrsep(&namelist, ",");
371 		if (!name) {
372 			free(namebase);
373 			return (-1);
374 		}
375 	} while ((s = tcpconnect(name)) < 0);
376 
377 	if (s >= maxfd)
378 		fatal("conalloc: fdno %d too high", s);
379 	if (fdcon[s].c_status)
380 		fatal("conalloc: attempt to reuse fdno %d", s);
381 
382 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
383 	fdcon[s].c_fd = s;
384 	fdcon[s].c_status = CS_CON;
385 	fdcon[s].c_namebase = namebase;
386 	fdcon[s].c_name = name;
387 	fdcon[s].c_namelist = namelist;
388 	fdcon[s].c_output_name = xstrdup(oname);
389 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
390 	fdcon[s].c_len = 4;
391 	fdcon[s].c_off = 0;
392 	fdcon[s].c_keytype = keytype;
393 	monotime_tv(&fdcon[s].c_tv);
394 	fdcon[s].c_tv.tv_sec += timeout;
395 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
396 	FD_SET(s, read_wait);
397 	ncon++;
398 	return (s);
399 }
400 
401 static void
402 confree(int s)
403 {
404 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
405 		fatal("confree: attempt to free bad fdno %d", s);
406 	free(fdcon[s].c_namebase);
407 	free(fdcon[s].c_output_name);
408 	if (fdcon[s].c_status == CS_KEYS)
409 		free(fdcon[s].c_data);
410 	fdcon[s].c_status = CS_UNUSED;
411 	fdcon[s].c_keytype = 0;
412 	if (fdcon[s].c_ssh) {
413 		ssh_packet_close(fdcon[s].c_ssh);
414 		free(fdcon[s].c_ssh);
415 		fdcon[s].c_ssh = NULL;
416 	} else
417 		close(s);
418 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
419 	FD_CLR(s, read_wait);
420 	ncon--;
421 }
422 
423 static void
424 contouch(int s)
425 {
426 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
427 	monotime_tv(&fdcon[s].c_tv);
428 	fdcon[s].c_tv.tv_sec += timeout;
429 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
430 }
431 
432 static int
433 conrecycle(int s)
434 {
435 	con *c = &fdcon[s];
436 	int ret;
437 
438 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
439 	confree(s);
440 	return (ret);
441 }
442 
443 static void
444 congreet(int s)
445 {
446 	int n = 0, remote_major = 0, remote_minor = 0;
447 	char buf[256], *cp;
448 	char remote_version[sizeof buf];
449 	size_t bufsiz;
450 	con *c = &fdcon[s];
451 
452 	/* send client banner */
453 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
454 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
455 	if (n < 0 || (size_t)n >= sizeof(buf)) {
456 		error("snprintf: buffer too small");
457 		confree(s);
458 		return;
459 	}
460 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
461 		error("write (%s): %s", c->c_name, strerror(errno));
462 		confree(s);
463 		return;
464 	}
465 
466 	for (;;) {
467 		memset(buf, '\0', sizeof(buf));
468 		bufsiz = sizeof(buf);
469 		cp = buf;
470 		while (bufsiz-- &&
471 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
472 			if (*cp == '\r')
473 				*cp = '\n';
474 			cp++;
475 		}
476 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
477 			break;
478 	}
479 	if (n == 0) {
480 		switch (errno) {
481 		case EPIPE:
482 			error("%s: Connection closed by remote host", c->c_name);
483 			break;
484 		case ECONNREFUSED:
485 			break;
486 		default:
487 			error("read (%s): %s", c->c_name, strerror(errno));
488 			break;
489 		}
490 		conrecycle(s);
491 		return;
492 	}
493 	if (*cp != '\n' && *cp != '\r') {
494 		error("%s: bad greeting", c->c_name);
495 		confree(s);
496 		return;
497 	}
498 	*cp = '\0';
499 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
500 		fatal("ssh_packet_set_connection failed");
501 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
502 	ssh_set_app_data(c->c_ssh, c);	/* back link */
503 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
504 	    &remote_major, &remote_minor, remote_version) == 3)
505 		c->c_ssh->compat = compat_datafellows(remote_version);
506 	else
507 		c->c_ssh->compat = 0;
508 	if (!ssh2_capable(remote_major, remote_minor)) {
509 		debug("%s doesn't support ssh2", c->c_name);
510 		confree(s);
511 		return;
512 	}
513 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
514 	    c->c_name, ssh_port, chop(buf));
515 	keygrab_ssh2(c);
516 	confree(s);
517 }
518 
519 static void
520 conread(int s)
521 {
522 	con *c = &fdcon[s];
523 	size_t n;
524 
525 	if (c->c_status == CS_CON) {
526 		congreet(s);
527 		return;
528 	}
529 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
530 	if (n == 0) {
531 		error("read (%s): %s", c->c_name, strerror(errno));
532 		confree(s);
533 		return;
534 	}
535 	c->c_off += n;
536 
537 	if (c->c_off == c->c_len)
538 		switch (c->c_status) {
539 		case CS_SIZE:
540 			c->c_plen = htonl(c->c_plen);
541 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
542 			c->c_off = 0;
543 			c->c_data = xmalloc(c->c_len);
544 			c->c_status = CS_KEYS;
545 			break;
546 		default:
547 			fatal("conread: invalid status %d", c->c_status);
548 			break;
549 		}
550 
551 	contouch(s);
552 }
553 
554 static void
555 conloop(void)
556 {
557 	struct timeval seltime, now;
558 	fd_set *r, *e;
559 	con *c;
560 	int i;
561 
562 	monotime_tv(&now);
563 	c = TAILQ_FIRST(&tq);
564 
565 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
566 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
567 		seltime = c->c_tv;
568 		seltime.tv_sec -= now.tv_sec;
569 		seltime.tv_usec -= now.tv_usec;
570 		if (seltime.tv_usec < 0) {
571 			seltime.tv_usec += 1000000;
572 			seltime.tv_sec--;
573 		}
574 	} else
575 		timerclear(&seltime);
576 
577 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
578 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
579 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
580 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
581 
582 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
583 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
584 		;
585 
586 	for (i = 0; i < maxfd; i++) {
587 		if (FD_ISSET(i, e)) {
588 			error("%s: exception!", fdcon[i].c_name);
589 			confree(i);
590 		} else if (FD_ISSET(i, r))
591 			conread(i);
592 	}
593 	free(r);
594 	free(e);
595 
596 	c = TAILQ_FIRST(&tq);
597 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
598 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
599 		int s = c->c_fd;
600 
601 		c = TAILQ_NEXT(c, c_link);
602 		conrecycle(s);
603 	}
604 }
605 
606 static void
607 do_host(char *host)
608 {
609 	char *name = strnnsep(&host, " \t\n");
610 	int j;
611 
612 	if (name == NULL)
613 		return;
614 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
615 		if (get_keytypes & j) {
616 			while (ncon >= MAXCON)
617 				conloop();
618 			conalloc(name, *host ? host : name, j);
619 		}
620 	}
621 }
622 
623 void
624 fatal(const char *fmt,...)
625 {
626 	va_list args;
627 
628 	va_start(args, fmt);
629 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
630 	va_end(args);
631 	exit(255);
632 }
633 
634 static void
635 usage(void)
636 {
637 	fprintf(stderr,
638 	    "usage: %s [-46cDHv] [-f file] [-p port] [-T timeout] [-t type]\n"
639 	    "\t\t   [host | addrlist namelist]\n",
640 	    __progname);
641 	exit(1);
642 }
643 
644 int
645 main(int argc, char **argv)
646 {
647 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
648 	int opt, fopt_count = 0, j;
649 	char *tname, *cp, *line = NULL;
650 	size_t linesize = 0;
651 	FILE *fp;
652 
653 	extern int optind;
654 	extern char *optarg;
655 
656 	ssh_malloc_init();	/* must be called before any mallocs */
657 	__progname = ssh_get_progname(argv[0]);
658 	seed_rng();
659 	TAILQ_INIT(&tq);
660 
661 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
662 	sanitise_stdfd();
663 
664 	if (argc <= 1)
665 		usage();
666 
667 	while ((opt = getopt(argc, argv, "cDHv46p:T:t:f:")) != -1) {
668 		switch (opt) {
669 		case 'H':
670 			hash_hosts = 1;
671 			break;
672 		case 'c':
673 			get_cert = 1;
674 			break;
675 		case 'D':
676 			print_sshfp = 1;
677 			break;
678 		case 'p':
679 			ssh_port = a2port(optarg);
680 			if (ssh_port <= 0) {
681 				fprintf(stderr, "Bad port '%s'\n", optarg);
682 				exit(1);
683 			}
684 			break;
685 		case 'T':
686 			timeout = convtime(optarg);
687 			if (timeout == -1 || timeout == 0) {
688 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
689 				usage();
690 			}
691 			break;
692 		case 'v':
693 			if (!debug_flag) {
694 				debug_flag = 1;
695 				log_level = SYSLOG_LEVEL_DEBUG1;
696 			}
697 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
698 				log_level++;
699 			else
700 				fatal("Too high debugging level.");
701 			break;
702 		case 'f':
703 			if (strcmp(optarg, "-") == 0)
704 				optarg = NULL;
705 			argv[fopt_count++] = optarg;
706 			break;
707 		case 't':
708 			get_keytypes = 0;
709 			tname = strtok(optarg, ",");
710 			while (tname) {
711 				int type = sshkey_type_from_name(tname);
712 
713 				switch (type) {
714 				case KEY_DSA:
715 					get_keytypes |= KT_DSA;
716 					break;
717 				case KEY_ECDSA:
718 					get_keytypes |= KT_ECDSA;
719 					break;
720 				case KEY_RSA:
721 					get_keytypes |= KT_RSA;
722 					break;
723 				case KEY_ED25519:
724 					get_keytypes |= KT_ED25519;
725 					break;
726 				case KEY_XMSS:
727 					get_keytypes |= KT_XMSS;
728 					break;
729 				case KEY_UNSPEC:
730 				default:
731 					fatal("Unknown key type \"%s\"", tname);
732 				}
733 				tname = strtok(NULL, ",");
734 			}
735 			break;
736 		case '4':
737 			IPv4or6 = AF_INET;
738 			break;
739 		case '6':
740 			IPv4or6 = AF_INET6;
741 			break;
742 		case '?':
743 		default:
744 			usage();
745 		}
746 	}
747 	if (optind == argc && !fopt_count)
748 		usage();
749 
750 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
751 
752 	maxfd = fdlim_get(1);
753 	if (maxfd < 0)
754 		fatal("%s: fdlim_get: bad value", __progname);
755 	if (maxfd > MAXMAXFD)
756 		maxfd = MAXMAXFD;
757 	if (MAXCON <= 0)
758 		fatal("%s: not enough file descriptors", __progname);
759 	if (maxfd > fdlim_get(0))
760 		fdlim_set(maxfd);
761 	fdcon = xcalloc(maxfd, sizeof(con));
762 
763 	read_wait_nfdset = howmany(maxfd, NFDBITS);
764 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
765 
766 	for (j = 0; j < fopt_count; j++) {
767 		if (argv[j] == NULL)
768 			fp = stdin;
769 		else if ((fp = fopen(argv[j], "r")) == NULL)
770 			fatal("%s: %s: %s", __progname, argv[j],
771 			    strerror(errno));
772 
773 		while (getline(&line, &linesize, fp) != -1) {
774 			/* Chomp off trailing whitespace and comments */
775 			if ((cp = strchr(line, '#')) == NULL)
776 				cp = line + strlen(line) - 1;
777 			while (cp >= line) {
778 				if (*cp == ' ' || *cp == '\t' ||
779 				    *cp == '\n' || *cp == '#')
780 					*cp-- = '\0';
781 				else
782 					break;
783 			}
784 
785 			/* Skip empty lines */
786 			if (*line == '\0')
787 				continue;
788 
789 			do_host(line);
790 		}
791 
792 		if (ferror(fp))
793 			fatal("%s: %s: %s", __progname, argv[j],
794 			    strerror(errno));
795 
796 		fclose(fp);
797 	}
798 	free(line);
799 
800 	while (optind < argc)
801 		do_host(argv[optind++]);
802 
803 	while (ncon > 0)
804 		conloop();
805 
806 	return (0);
807 }
808