xref: /openbsd/usr.bin/ssh/ssh-keyscan.c (revision 55cc5ba3) 
1 /* $OpenBSD: ssh-keyscan.c,v 1.139 2021/01/27 09:26:54 djm 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 #ifdef WITH_OPENSSL
17 #include <openssl/bn.h>
18 #endif
19 
20 #include <errno.h>
21 #include <netdb.h>
22 #include <stdarg.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <signal.h>
26 #include <string.h>
27 #include <unistd.h>
28 
29 #include "xmalloc.h"
30 #include "ssh.h"
31 #include "sshbuf.h"
32 #include "sshkey.h"
33 #include "cipher.h"
34 #include "kex.h"
35 #include "compat.h"
36 #include "myproposal.h"
37 #include "packet.h"
38 #include "dispatch.h"
39 #include "log.h"
40 #include "atomicio.h"
41 #include "misc.h"
42 #include "hostfile.h"
43 #include "ssherr.h"
44 #include "ssh_api.h"
45 #include "dns.h"
46 
47 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
48    Default value is AF_UNSPEC means both IPv4 and IPv6. */
49 int IPv4or6 = AF_UNSPEC;
50 
51 int ssh_port = SSH_DEFAULT_PORT;
52 
53 #define KT_DSA		(1)
54 #define KT_RSA		(1<<1)
55 #define KT_ECDSA	(1<<2)
56 #define KT_ED25519	(1<<3)
57 #define KT_XMSS		(1<<4)
58 #define KT_ECDSA_SK	(1<<5)
59 #define KT_ED25519_SK	(1<<6)
60 
61 #define KT_MIN		KT_DSA
62 #define KT_MAX		KT_ED25519_SK
63 
64 int get_cert = 0;
65 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
66 
67 int hash_hosts = 0;		/* Hash hostname on output */
68 
69 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
70 
71 int found_one = 0;		/* Successfully found a key */
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 /*
87  * Keep a connection structure for each file descriptor.  The state
88  * associated with file descriptor n is held in fdcon[n].
89  */
90 typedef struct Connection {
91 	u_char c_status;	/* State of connection on this file desc. */
92 #define CS_UNUSED 0		/* File descriptor unused */
93 #define CS_CON 1		/* Waiting to connect/read greeting */
94 #define CS_SIZE 2		/* Waiting to read initial packet size */
95 #define CS_KEYS 3		/* Waiting to read public key packet */
96 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
97 	int c_plen;		/* Packet length field for ssh packet */
98 	int c_len;		/* Total bytes which must be read. */
99 	int c_off;		/* Length of data read so far. */
100 	int c_keytype;		/* Only one of KT_* */
101 	sig_atomic_t c_done;	/* SSH2 done */
102 	char *c_namebase;	/* Address to free for c_name and c_namelist */
103 	char *c_name;		/* Hostname of connection for errors */
104 	char *c_namelist;	/* Pointer to other possible addresses */
105 	char *c_output_name;	/* Hostname of connection for output */
106 	char *c_data;		/* Data read from this fd */
107 	struct ssh *c_ssh;	/* SSH-connection */
108 	struct timeval c_tv;	/* Time at which connection gets aborted */
109 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
110 } con;
111 
112 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
113 con *fdcon;
114 
115 static void keyprint(con *c, struct sshkey *key);
116 
117 static int
118 fdlim_get(int hard)
119 {
120 	struct rlimit rlfd;
121 
122 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
123 		return (-1);
124 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
125 		return sysconf(_SC_OPEN_MAX);
126 	else
127 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
128 }
129 
130 static int
131 fdlim_set(int lim)
132 {
133 	struct rlimit rlfd;
134 
135 	if (lim <= 0)
136 		return (-1);
137 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
138 		return (-1);
139 	rlfd.rlim_cur = lim;
140 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
141 		return (-1);
142 	return (0);
143 }
144 
145 /*
146  * This is an strsep function that returns a null field for adjacent
147  * separators.  This is the same as the 4.4BSD strsep, but different from the
148  * one in the GNU libc.
149  */
150 static char *
151 xstrsep(char **str, const char *delim)
152 {
153 	char *s, *e;
154 
155 	if (!**str)
156 		return (NULL);
157 
158 	s = *str;
159 	e = s + strcspn(s, delim);
160 
161 	if (*e != '\0')
162 		*e++ = '\0';
163 	*str = e;
164 
165 	return (s);
166 }
167 
168 /*
169  * Get the next non-null token (like GNU strsep).  Strsep() will return a
170  * null token for two adjacent separators, so we may have to loop.
171  */
172 static char *
173 strnnsep(char **stringp, char *delim)
174 {
175 	char *tok;
176 
177 	do {
178 		tok = xstrsep(stringp, delim);
179 	} while (tok && *tok == '\0');
180 	return (tok);
181 }
182 
183 
184 static int
185 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
186 {
187 	con *c;
188 
189 	if ((c = ssh_get_app_data(ssh)) != NULL)
190 		keyprint(c, hostkey);
191 	/* always abort key exchange */
192 	return -1;
193 }
194 
195 static int
196 ssh2_capable(int remote_major, int remote_minor)
197 {
198 	switch (remote_major) {
199 	case 1:
200 		if (remote_minor == 99)
201 			return 1;
202 		break;
203 	case 2:
204 		return 1;
205 	default:
206 		break;
207 	}
208 	return 0;
209 }
210 
211 static void
212 keygrab_ssh2(con *c)
213 {
214 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
215 	int r;
216 
217 	switch (c->c_keytype) {
218 	case KT_DSA:
219 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
220 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
221 		break;
222 	case KT_RSA:
223 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
224 		    "rsa-sha2-512-cert-v01@openssh.com,"
225 		    "rsa-sha2-256-cert-v01@openssh.com,"
226 		    "ssh-rsa-cert-v01@openssh.com" :
227 		    "rsa-sha2-512,"
228 		    "rsa-sha2-256,"
229 		    "ssh-rsa";
230 		break;
231 	case KT_ED25519:
232 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
233 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
234 		break;
235 	case KT_XMSS:
236 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
237 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
238 		break;
239 	case KT_ECDSA:
240 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
241 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
242 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
243 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
244 		    "ecdsa-sha2-nistp256,"
245 		    "ecdsa-sha2-nistp384,"
246 		    "ecdsa-sha2-nistp521";
247 		break;
248 	case KT_ECDSA_SK:
249 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
250 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
251 		    "sk-ecdsa-sha2-nistp256@openssh.com";
252 		break;
253 	case KT_ED25519_SK:
254 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
255 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
256 		    "sk-ssh-ed25519@openssh.com";
257 		break;
258 	default:
259 		fatal("unknown key type %d", c->c_keytype);
260 		break;
261 	}
262 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
263 		free(c->c_ssh);
264 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
265 		exit(1);
266 	}
267 #ifdef WITH_OPENSSL
268 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
269 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
270 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
271 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
272 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
273 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
274 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
275 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
276 #endif
277 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
278 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
279 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
280 	/*
281 	 * do the key-exchange until an error occurs or until
282 	 * the key_print_wrapper() callback sets c_done.
283 	 */
284 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
285 }
286 
287 static void
288 keyprint_one(const char *host, struct sshkey *key)
289 {
290 	char *hostport;
291 	const char *known_host, *hashed;
292 
293 	found_one = 1;
294 
295 	if (print_sshfp) {
296 		export_dns_rr(host, key, stdout, 0);
297 		return;
298 	}
299 
300 	hostport = put_host_port(host, ssh_port);
301 	lowercase(hostport);
302 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
303 		fatal("host_hash failed");
304 	known_host = hash_hosts ? hashed : hostport;
305 	if (!get_cert)
306 		fprintf(stdout, "%s ", known_host);
307 	sshkey_write(key, stdout);
308 	fputs("\n", stdout);
309 	free(hostport);
310 }
311 
312 static void
313 keyprint(con *c, struct sshkey *key)
314 {
315 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
316 	char *host, *ohosts;
317 
318 	if (key == NULL)
319 		return;
320 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
321 		keyprint_one(hosts, key);
322 		return;
323 	}
324 	ohosts = hosts = xstrdup(hosts);
325 	while ((host = strsep(&hosts, ",")) != NULL)
326 		keyprint_one(host, key);
327 	free(ohosts);
328 }
329 
330 static int
331 tcpconnect(char *host)
332 {
333 	struct addrinfo hints, *ai, *aitop;
334 	char strport[NI_MAXSERV];
335 	int gaierr, s = -1;
336 
337 	snprintf(strport, sizeof strport, "%d", ssh_port);
338 	memset(&hints, 0, sizeof(hints));
339 	hints.ai_family = IPv4or6;
340 	hints.ai_socktype = SOCK_STREAM;
341 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
342 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
343 		return -1;
344 	}
345 	for (ai = aitop; ai; ai = ai->ai_next) {
346 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
347 		if (s == -1) {
348 			error("socket: %s", strerror(errno));
349 			continue;
350 		}
351 		if (set_nonblock(s) == -1)
352 			fatal_f("set_nonblock(%d)", s);
353 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
354 		    errno != EINPROGRESS)
355 			error("connect (`%s'): %s", host, strerror(errno));
356 		else
357 			break;
358 		close(s);
359 		s = -1;
360 	}
361 	freeaddrinfo(aitop);
362 	return s;
363 }
364 
365 static int
366 conalloc(char *iname, char *oname, int keytype)
367 {
368 	char *namebase, *name, *namelist;
369 	int s;
370 
371 	namebase = namelist = xstrdup(iname);
372 
373 	do {
374 		name = xstrsep(&namelist, ",");
375 		if (!name) {
376 			free(namebase);
377 			return (-1);
378 		}
379 	} while ((s = tcpconnect(name)) < 0);
380 
381 	if (s >= maxfd)
382 		fatal("conalloc: fdno %d too high", s);
383 	if (fdcon[s].c_status)
384 		fatal("conalloc: attempt to reuse fdno %d", s);
385 
386 	debug3_f("oname %s kt %d", oname, keytype);
387 	fdcon[s].c_fd = s;
388 	fdcon[s].c_status = CS_CON;
389 	fdcon[s].c_namebase = namebase;
390 	fdcon[s].c_name = name;
391 	fdcon[s].c_namelist = namelist;
392 	fdcon[s].c_output_name = xstrdup(oname);
393 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
394 	fdcon[s].c_len = 4;
395 	fdcon[s].c_off = 0;
396 	fdcon[s].c_keytype = keytype;
397 	monotime_tv(&fdcon[s].c_tv);
398 	fdcon[s].c_tv.tv_sec += timeout;
399 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
400 	FD_SET(s, read_wait);
401 	ncon++;
402 	return (s);
403 }
404 
405 static void
406 confree(int s)
407 {
408 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
409 		fatal("confree: attempt to free bad fdno %d", s);
410 	free(fdcon[s].c_namebase);
411 	free(fdcon[s].c_output_name);
412 	if (fdcon[s].c_status == CS_KEYS)
413 		free(fdcon[s].c_data);
414 	fdcon[s].c_status = CS_UNUSED;
415 	fdcon[s].c_keytype = 0;
416 	if (fdcon[s].c_ssh) {
417 		ssh_packet_close(fdcon[s].c_ssh);
418 		free(fdcon[s].c_ssh);
419 		fdcon[s].c_ssh = NULL;
420 	} else
421 		close(s);
422 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
423 	FD_CLR(s, read_wait);
424 	ncon--;
425 }
426 
427 static void
428 contouch(int s)
429 {
430 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
431 	monotime_tv(&fdcon[s].c_tv);
432 	fdcon[s].c_tv.tv_sec += timeout;
433 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
434 }
435 
436 static int
437 conrecycle(int s)
438 {
439 	con *c = &fdcon[s];
440 	int ret;
441 
442 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
443 	confree(s);
444 	return (ret);
445 }
446 
447 static void
448 congreet(int s)
449 {
450 	int n = 0, remote_major = 0, remote_minor = 0;
451 	char buf[256], *cp;
452 	char remote_version[sizeof buf];
453 	size_t bufsiz;
454 	con *c = &fdcon[s];
455 
456 	/* send client banner */
457 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
458 	    PROTOCOL_MAJOR_2, 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 
470 	for (;;) {
471 		memset(buf, '\0', sizeof(buf));
472 		bufsiz = sizeof(buf);
473 		cp = buf;
474 		while (bufsiz-- &&
475 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
476 			if (*cp == '\r')
477 				*cp = '\n';
478 			cp++;
479 		}
480 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
481 			break;
482 	}
483 	if (n == 0) {
484 		switch (errno) {
485 		case EPIPE:
486 			error("%s: Connection closed by remote host", c->c_name);
487 			break;
488 		case ECONNREFUSED:
489 			break;
490 		default:
491 			error("read (%s): %s", c->c_name, strerror(errno));
492 			break;
493 		}
494 		conrecycle(s);
495 		return;
496 	}
497 	if (*cp != '\n' && *cp != '\r') {
498 		error("%s: bad greeting", c->c_name);
499 		confree(s);
500 		return;
501 	}
502 	*cp = '\0';
503 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
504 		fatal("ssh_packet_set_connection failed");
505 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
506 	ssh_set_app_data(c->c_ssh, c);	/* back link */
507 	c->c_ssh->compat = 0;
508 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
509 	    &remote_major, &remote_minor, remote_version) == 3)
510 		compat_banner(c->c_ssh, remote_version);
511 	if (!ssh2_capable(remote_major, remote_minor)) {
512 		debug("%s doesn't support ssh2", c->c_name);
513 		confree(s);
514 		return;
515 	}
516 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
517 	    c->c_name, ssh_port, chop(buf));
518 	keygrab_ssh2(c);
519 	confree(s);
520 }
521 
522 static void
523 conread(int s)
524 {
525 	con *c = &fdcon[s];
526 	size_t n;
527 
528 	if (c->c_status == CS_CON) {
529 		congreet(s);
530 		return;
531 	}
532 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
533 	if (n == 0) {
534 		error("read (%s): %s", c->c_name, strerror(errno));
535 		confree(s);
536 		return;
537 	}
538 	c->c_off += n;
539 
540 	if (c->c_off == c->c_len)
541 		switch (c->c_status) {
542 		case CS_SIZE:
543 			c->c_plen = htonl(c->c_plen);
544 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
545 			c->c_off = 0;
546 			c->c_data = xmalloc(c->c_len);
547 			c->c_status = CS_KEYS;
548 			break;
549 		default:
550 			fatal("conread: invalid status %d", c->c_status);
551 			break;
552 		}
553 
554 	contouch(s);
555 }
556 
557 static void
558 conloop(void)
559 {
560 	struct timeval seltime, now;
561 	fd_set *r, *e;
562 	con *c;
563 	int i;
564 
565 	monotime_tv(&now);
566 	c = TAILQ_FIRST(&tq);
567 
568 	if (c && timercmp(&c->c_tv, &now, >))
569 		timersub(&c->c_tv, &now, &seltime);
570 	else
571 		timerclear(&seltime);
572 
573 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
574 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
575 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
576 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
577 
578 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
579 	    (errno == EAGAIN || errno == EINTR))
580 		;
581 
582 	for (i = 0; i < maxfd; i++) {
583 		if (FD_ISSET(i, e)) {
584 			error("%s: exception!", fdcon[i].c_name);
585 			confree(i);
586 		} else if (FD_ISSET(i, r))
587 			conread(i);
588 	}
589 	free(r);
590 	free(e);
591 
592 	c = TAILQ_FIRST(&tq);
593 	while (c && timercmp(&c->c_tv, &now, <)) {
594 		int s = c->c_fd;
595 
596 		c = TAILQ_NEXT(c, c_link);
597 		conrecycle(s);
598 	}
599 }
600 
601 static void
602 do_host(char *host)
603 {
604 	char *name = strnnsep(&host, " \t\n");
605 	int j;
606 
607 	if (name == NULL)
608 		return;
609 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
610 		if (get_keytypes & j) {
611 			while (ncon >= MAXCON)
612 				conloop();
613 			conalloc(name, *host ? host : name, j);
614 		}
615 	}
616 }
617 
618 void
619 sshfatal(const char *file, const char *func, int line, int showfunc,
620     LogLevel level, const char *suffix, const char *fmt, ...)
621 {
622 	va_list args;
623 
624 	va_start(args, fmt);
625 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
626 	va_end(args);
627 	cleanup_exit(255);
628 }
629 
630 static void
631 usage(void)
632 {
633 	fprintf(stderr,
634 	    "usage: %s [-46cDHv] [-f file] [-p port] [-T timeout] [-t type]\n"
635 	    "\t\t   [host | addrlist namelist]\n",
636 	    __progname);
637 	exit(1);
638 }
639 
640 int
641 main(int argc, char **argv)
642 {
643 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
644 	int opt, fopt_count = 0, j;
645 	char *tname, *cp, *line = NULL;
646 	size_t linesize = 0;
647 	FILE *fp;
648 
649 	extern int optind;
650 	extern char *optarg;
651 
652 	TAILQ_INIT(&tq);
653 
654 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
655 	sanitise_stdfd();
656 
657 	if (argc <= 1)
658 		usage();
659 
660 	while ((opt = getopt(argc, argv, "cDHv46p:T:t:f:")) != -1) {
661 		switch (opt) {
662 		case 'H':
663 			hash_hosts = 1;
664 			break;
665 		case 'c':
666 			get_cert = 1;
667 			break;
668 		case 'D':
669 			print_sshfp = 1;
670 			break;
671 		case 'p':
672 			ssh_port = a2port(optarg);
673 			if (ssh_port <= 0) {
674 				fprintf(stderr, "Bad port '%s'\n", optarg);
675 				exit(1);
676 			}
677 			break;
678 		case 'T':
679 			timeout = convtime(optarg);
680 			if (timeout == -1 || timeout == 0) {
681 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
682 				usage();
683 			}
684 			break;
685 		case 'v':
686 			if (!debug_flag) {
687 				debug_flag = 1;
688 				log_level = SYSLOG_LEVEL_DEBUG1;
689 			}
690 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
691 				log_level++;
692 			else
693 				fatal("Too high debugging level.");
694 			break;
695 		case 'f':
696 			if (strcmp(optarg, "-") == 0)
697 				optarg = NULL;
698 			argv[fopt_count++] = optarg;
699 			break;
700 		case 't':
701 			get_keytypes = 0;
702 			tname = strtok(optarg, ",");
703 			while (tname) {
704 				int type = sshkey_type_from_name(tname);
705 
706 				switch (type) {
707 				case KEY_DSA:
708 					get_keytypes |= KT_DSA;
709 					break;
710 				case KEY_ECDSA:
711 					get_keytypes |= KT_ECDSA;
712 					break;
713 				case KEY_RSA:
714 					get_keytypes |= KT_RSA;
715 					break;
716 				case KEY_ED25519:
717 					get_keytypes |= KT_ED25519;
718 					break;
719 				case KEY_XMSS:
720 					get_keytypes |= KT_XMSS;
721 					break;
722 				case KEY_ED25519_SK:
723 					get_keytypes |= KT_ED25519_SK;
724 					break;
725 				case KEY_ECDSA_SK:
726 					get_keytypes |= KT_ECDSA_SK;
727 					break;
728 				case KEY_UNSPEC:
729 				default:
730 					fatal("Unknown key type \"%s\"", tname);
731 				}
732 				tname = strtok(NULL, ",");
733 			}
734 			break;
735 		case '4':
736 			IPv4or6 = AF_INET;
737 			break;
738 		case '6':
739 			IPv4or6 = AF_INET6;
740 			break;
741 		case '?':
742 		default:
743 			usage();
744 		}
745 	}
746 	if (optind == argc && !fopt_count)
747 		usage();
748 
749 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
750 
751 	maxfd = fdlim_get(1);
752 	if (maxfd < 0)
753 		fatal("%s: fdlim_get: bad value", __progname);
754 	if (maxfd > MAXMAXFD)
755 		maxfd = MAXMAXFD;
756 	if (MAXCON <= 0)
757 		fatal("%s: not enough file descriptors", __progname);
758 	if (maxfd > fdlim_get(0))
759 		fdlim_set(maxfd);
760 	fdcon = xcalloc(maxfd, sizeof(con));
761 
762 	read_wait_nfdset = howmany(maxfd, NFDBITS);
763 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
764 
765 	for (j = 0; j < fopt_count; j++) {
766 		if (argv[j] == NULL)
767 			fp = stdin;
768 		else if ((fp = fopen(argv[j], "r")) == NULL)
769 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
770 
771 		while (getline(&line, &linesize, fp) != -1) {
772 			/* Chomp off trailing whitespace and comments */
773 			if ((cp = strchr(line, '#')) == NULL)
774 				cp = line + strlen(line) - 1;
775 			while (cp >= line) {
776 				if (*cp == ' ' || *cp == '\t' ||
777 				    *cp == '\n' || *cp == '#')
778 					*cp-- = '\0';
779 				else
780 					break;
781 			}
782 
783 			/* Skip empty lines */
784 			if (*line == '\0')
785 				continue;
786 
787 			do_host(line);
788 		}
789 
790 		if (ferror(fp))
791 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
792 
793 		fclose(fp);
794 	}
795 	free(line);
796 
797 	while (optind < argc)
798 		do_host(argv[optind++]);
799 
800 	while (ncon > 0)
801 		conloop();
802 
803 	return found_one ? 0 : 1;
804 }
805