xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision 627f7eb200a4419d89b531d55fccd2ee3ffdcde0)
1 /*	$NetBSD: ssh-keyscan.c,v 1.28 2021/03/05 17:47:16 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.139 2021/01/27 09:26:54 djm Exp $ */
3 
4 /*
5  * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
6  *
7  * Modification and redistribution in source and binary forms is
8  * permitted provided that due credit is given to the author and the
9  * OpenBSD project by leaving this copyright notice intact.
10  */
11 
12 #include "includes.h"
13 __RCSID("$NetBSD: ssh-keyscan.c,v 1.28 2021/03/05 17:47:16 christos Exp $");
14 
15 #include <sys/param.h>
16 #include <sys/types.h>
17 #include <sys/socket.h>
18 #include <sys/queue.h>
19 #include <sys/time.h>
20 #include <sys/resource.h>
21 
22 #ifdef WITH_OPENSSL
23 #include <openssl/bn.h>
24 #endif
25 
26 #include <errno.h>
27 #include <netdb.h>
28 #include <stdarg.h>
29 #include <stdio.h>
30 #include <stdlib.h>
31 #include <signal.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 #include "xmalloc.h"
36 #include "ssh.h"
37 #include "sshbuf.h"
38 #include "sshkey.h"
39 #include "cipher.h"
40 #include "kex.h"
41 #include "compat.h"
42 #include "myproposal.h"
43 #include "packet.h"
44 #include "dispatch.h"
45 #include "log.h"
46 #include "atomicio.h"
47 #include "misc.h"
48 #include "hostfile.h"
49 #include "ssherr.h"
50 #include "ssh_api.h"
51 #include "dns.h"
52 
53 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
54    Default value is AF_UNSPEC means both IPv4 and IPv6. */
55 int IPv4or6 = AF_UNSPEC;
56 
57 int ssh_port = SSH_DEFAULT_PORT;
58 
59 #define KT_DSA		(1)
60 #define KT_RSA		(1<<1)
61 #define KT_ECDSA	(1<<2)
62 #define KT_ED25519	(1<<3)
63 #define KT_XMSS		(1<<4)
64 #define KT_ECDSA_SK	(1<<5)
65 #define KT_ED25519_SK	(1<<6)
66 
67 #define KT_MIN		KT_DSA
68 #define KT_MAX		KT_ED25519_SK
69 
70 int get_cert = 0;
71 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
72 
73 int hash_hosts = 0;		/* Hash hostname on output */
74 
75 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
76 
77 int found_one = 0;		/* Successfully found a key */
78 
79 #define MAXMAXFD 256
80 
81 /* The number of seconds after which to give up on a TCP connection */
82 int timeout = 5;
83 
84 int maxfd;
85 #define MAXCON (maxfd - 10)
86 
87 extern char *__progname;
88 fd_set *read_wait;
89 size_t read_wait_nfdset;
90 int ncon;
91 
92 /*
93  * Keep a connection structure for each file descriptor.  The state
94  * associated with file descriptor n is held in fdcon[n].
95  */
96 typedef struct Connection {
97 	u_char c_status;	/* State of connection on this file desc. */
98 #define CS_UNUSED 0		/* File descriptor unused */
99 #define CS_CON 1		/* Waiting to connect/read greeting */
100 #define CS_SIZE 2		/* Waiting to read initial packet size */
101 #define CS_KEYS 3		/* Waiting to read public key packet */
102 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
103 	int c_plen;		/* Packet length field for ssh packet */
104 	int c_len;		/* Total bytes which must be read. */
105 	int c_off;		/* Length of data read so far. */
106 	int c_keytype;		/* Only one of KT_* */
107 	sig_atomic_t c_done;	/* SSH2 done */
108 	char *c_namebase;	/* Address to free for c_name and c_namelist */
109 	char *c_name;		/* Hostname of connection for errors */
110 	char *c_namelist;	/* Pointer to other possible addresses */
111 	char *c_output_name;	/* Hostname of connection for output */
112 	char *c_data;		/* Data read from this fd */
113 	struct ssh *c_ssh;	/* SSH-connection */
114 	struct timeval c_tv;	/* Time at which connection gets aborted */
115 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
116 } con;
117 
118 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
119 con *fdcon;
120 
121 static void keyprint(con *c, struct sshkey *key);
122 
123 static int
124 fdlim_get(int hard)
125 {
126 	struct rlimit rlfd;
127 
128 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
129 		return (-1);
130 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
131 		return sysconf(_SC_OPEN_MAX);
132 	else
133 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
134 }
135 
136 static int
137 fdlim_set(int lim)
138 {
139 	struct rlimit rlfd;
140 
141 	if (lim <= 0)
142 		return (-1);
143 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
144 		return (-1);
145 	rlfd.rlim_cur = lim;
146 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
147 		return (-1);
148 	return (0);
149 }
150 
151 /*
152  * This is an strsep function that returns a null field for adjacent
153  * separators.  This is the same as the 4.4BSD strsep, but different from the
154  * one in the GNU libc.
155  */
156 static char *
157 xstrsep(char **str, const char *delim)
158 {
159 	char *s, *e;
160 
161 	if (!**str)
162 		return (NULL);
163 
164 	s = *str;
165 	e = s + strcspn(s, delim);
166 
167 	if (*e != '\0')
168 		*e++ = '\0';
169 	*str = e;
170 
171 	return (s);
172 }
173 
174 /*
175  * Get the next non-null token (like GNU strsep).  Strsep() will return a
176  * null token for two adjacent separators, so we may have to loop.
177  */
178 static char *
179 strnnsep(char **stringp, const char *delim)
180 {
181 	char *tok;
182 
183 	do {
184 		tok = xstrsep(stringp, delim);
185 	} while (tok && *tok == '\0');
186 	return (tok);
187 }
188 
189 
190 static int
191 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
192 {
193 	con *c;
194 
195 	if ((c = ssh_get_app_data(ssh)) != NULL)
196 		keyprint(c, hostkey);
197 	/* always abort key exchange */
198 	return -1;
199 }
200 
201 static int
202 ssh2_capable(int remote_major, int remote_minor)
203 {
204 	switch (remote_major) {
205 	case 1:
206 		if (remote_minor == 99)
207 			return 1;
208 		break;
209 	case 2:
210 		return 1;
211 	default:
212 		break;
213 	}
214 	return 0;
215 }
216 
217 static void
218 keygrab_ssh2(con *c)
219 {
220 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
221 	int r;
222 
223 	switch (c->c_keytype) {
224 	case KT_DSA:
225 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
226 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
227 		break;
228 	case KT_RSA:
229 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
230 		    "rsa-sha2-512-cert-v01@openssh.com,"
231 		    "rsa-sha2-256-cert-v01@openssh.com,"
232 		    "ssh-rsa-cert-v01@openssh.com" :
233 		    "rsa-sha2-512,"
234 		    "rsa-sha2-256,"
235 		    "ssh-rsa";
236 		break;
237 	case KT_ED25519:
238 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
239 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
240 		break;
241 	case KT_XMSS:
242 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
243 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
244 		break;
245 	case KT_ECDSA:
246 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
247 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
248 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
249 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
250 		    "ecdsa-sha2-nistp256,"
251 		    "ecdsa-sha2-nistp384,"
252 		    "ecdsa-sha2-nistp521";
253 		break;
254 	case KT_ECDSA_SK:
255 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
256 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
257 		    "sk-ecdsa-sha2-nistp256@openssh.com";
258 		break;
259 	case KT_ED25519_SK:
260 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
261 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
262 		    "sk-ssh-ed25519@openssh.com";
263 		break;
264 	default:
265 		fatal("unknown key type %d", c->c_keytype);
266 		break;
267 	}
268 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
269 		free(c->c_ssh);
270 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
271 		exit(1);
272 	}
273 #ifdef WITH_OPENSSL
274 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
275 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
276 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
277 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
278 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
279 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
280 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
281 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
282 #endif
283 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
284 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
285 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
286 	/*
287 	 * do the key-exchange until an error occurs or until
288 	 * the key_print_wrapper() callback sets c_done.
289 	 */
290 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
291 }
292 
293 static void
294 keyprint_one(const char *host, struct sshkey *key)
295 {
296 	char *hostport;
297 	const char *known_host, *hashed;
298 
299 	found_one = 1;
300 
301 	if (print_sshfp) {
302 		export_dns_rr(host, key, stdout, 0);
303 		return;
304 	}
305 
306 	hostport = put_host_port(host, ssh_port);
307 	lowercase(hostport);
308 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
309 		fatal("host_hash failed");
310 	known_host = hash_hosts ? hashed : hostport;
311 	if (!get_cert)
312 		fprintf(stdout, "%s ", known_host);
313 	sshkey_write(key, stdout);
314 	fputs("\n", stdout);
315 	free(hostport);
316 }
317 
318 static void
319 keyprint(con *c, struct sshkey *key)
320 {
321 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
322 	char *host, *ohosts;
323 
324 	if (key == NULL)
325 		return;
326 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
327 		keyprint_one(hosts, key);
328 		return;
329 	}
330 	ohosts = hosts = xstrdup(hosts);
331 	while ((host = strsep(&hosts, ",")) != NULL)
332 		keyprint_one(host, key);
333 	free(ohosts);
334 }
335 
336 static int
337 tcpconnect(char *host)
338 {
339 	struct addrinfo hints, *ai, *aitop;
340 	char strport[NI_MAXSERV];
341 	int gaierr, s = -1;
342 
343 	snprintf(strport, sizeof strport, "%d", ssh_port);
344 	memset(&hints, 0, sizeof(hints));
345 	hints.ai_family = IPv4or6;
346 	hints.ai_socktype = SOCK_STREAM;
347 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
348 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
349 		return -1;
350 	}
351 	for (ai = aitop; ai; ai = ai->ai_next) {
352 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
353 		if (s == -1) {
354 			error("socket: %s", strerror(errno));
355 			continue;
356 		}
357 		if (set_nonblock(s) == -1)
358 			fatal_f("set_nonblock(%d)", s);
359 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
360 		    errno != EINPROGRESS)
361 			error("connect (`%s'): %s", host, strerror(errno));
362 		else
363 			break;
364 		close(s);
365 		s = -1;
366 	}
367 	freeaddrinfo(aitop);
368 	return s;
369 }
370 
371 static int
372 conalloc(char *iname, char *oname, int keytype)
373 {
374 	char *namebase, *name, *namelist;
375 	int s;
376 
377 	namebase = namelist = xstrdup(iname);
378 
379 	do {
380 		name = xstrsep(&namelist, ",");
381 		if (!name) {
382 			free(namebase);
383 			return (-1);
384 		}
385 	} while ((s = tcpconnect(name)) < 0);
386 
387 	if (s >= maxfd)
388 		fatal("conalloc: fdno %d too high", s);
389 	if (fdcon[s].c_status)
390 		fatal("conalloc: attempt to reuse fdno %d", s);
391 
392 	debug3_f("oname %s kt %d", oname, keytype);
393 	fdcon[s].c_fd = s;
394 	fdcon[s].c_status = CS_CON;
395 	fdcon[s].c_namebase = namebase;
396 	fdcon[s].c_name = name;
397 	fdcon[s].c_namelist = namelist;
398 	fdcon[s].c_output_name = xstrdup(oname);
399 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
400 	fdcon[s].c_len = 4;
401 	fdcon[s].c_off = 0;
402 	fdcon[s].c_keytype = keytype;
403 	monotime_tv(&fdcon[s].c_tv);
404 	fdcon[s].c_tv.tv_sec += timeout;
405 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
406 	FD_SET(s, read_wait);
407 	ncon++;
408 	return (s);
409 }
410 
411 static void
412 confree(int s)
413 {
414 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
415 		fatal("confree: attempt to free bad fdno %d", s);
416 	free(fdcon[s].c_namebase);
417 	free(fdcon[s].c_output_name);
418 	if (fdcon[s].c_status == CS_KEYS)
419 		free(fdcon[s].c_data);
420 	fdcon[s].c_status = CS_UNUSED;
421 	fdcon[s].c_keytype = 0;
422 	if (fdcon[s].c_ssh) {
423 		ssh_packet_close(fdcon[s].c_ssh);
424 		free(fdcon[s].c_ssh);
425 		fdcon[s].c_ssh = NULL;
426 	} else
427 		close(s);
428 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
429 	FD_CLR(s, read_wait);
430 	ncon--;
431 }
432 
433 static void
434 contouch(int s)
435 {
436 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
437 	monotime_tv(&fdcon[s].c_tv);
438 	fdcon[s].c_tv.tv_sec += timeout;
439 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
440 }
441 
442 static int
443 conrecycle(int s)
444 {
445 	con *c = &fdcon[s];
446 	int ret;
447 
448 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
449 	confree(s);
450 	return (ret);
451 }
452 
453 static void
454 congreet(int s)
455 {
456 	int n = 0, remote_major = 0, remote_minor = 0;
457 	char buf[256], *cp;
458 	char remote_version[sizeof buf];
459 	size_t bufsiz;
460 	con *c = &fdcon[s];
461 
462 	/* send client banner */
463 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
464 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
465 	if (n < 0 || (size_t)n >= sizeof(buf)) {
466 		error("snprintf: buffer too small");
467 		confree(s);
468 		return;
469 	}
470 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
471 		error("write (%s): %s", c->c_name, strerror(errno));
472 		confree(s);
473 		return;
474 	}
475 
476 	for (;;) {
477 		memset(buf, '\0', sizeof(buf));
478 		bufsiz = sizeof(buf);
479 		cp = buf;
480 		while (bufsiz-- &&
481 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
482 			if (*cp == '\r')
483 				*cp = '\n';
484 			cp++;
485 		}
486 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
487 			break;
488 	}
489 	if (n == 0) {
490 		switch (errno) {
491 		case EPIPE:
492 			error("%s: Connection closed by remote host", c->c_name);
493 			break;
494 		case ECONNREFUSED:
495 			break;
496 		default:
497 			error("read (%s): %s", c->c_name, strerror(errno));
498 			break;
499 		}
500 		conrecycle(s);
501 		return;
502 	}
503 	if (*cp != '\n' && *cp != '\r') {
504 		error("%s: bad greeting", c->c_name);
505 		confree(s);
506 		return;
507 	}
508 	*cp = '\0';
509 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
510 		fatal("ssh_packet_set_connection failed");
511 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
512 	ssh_set_app_data(c->c_ssh, c);	/* back link */
513 	c->c_ssh->compat = 0;
514 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
515 	    &remote_major, &remote_minor, remote_version) == 3)
516 		compat_banner(c->c_ssh, remote_version);
517 	if (!ssh2_capable(remote_major, remote_minor)) {
518 		debug("%s doesn't support ssh2", c->c_name);
519 		confree(s);
520 		return;
521 	}
522 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
523 	    c->c_name, ssh_port, chop(buf));
524 	keygrab_ssh2(c);
525 	confree(s);
526 }
527 
528 static void
529 conread(int s)
530 {
531 	con *c = &fdcon[s];
532 	size_t n;
533 
534 	if (c->c_status == CS_CON) {
535 		congreet(s);
536 		return;
537 	}
538 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
539 	if (n == 0) {
540 		error("read (%s): %s", c->c_name, strerror(errno));
541 		confree(s);
542 		return;
543 	}
544 	c->c_off += n;
545 
546 	if (c->c_off == c->c_len)
547 		switch (c->c_status) {
548 		case CS_SIZE:
549 			c->c_plen = htonl(c->c_plen);
550 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
551 			c->c_off = 0;
552 			c->c_data = xmalloc(c->c_len);
553 			c->c_status = CS_KEYS;
554 			break;
555 		default:
556 			fatal("conread: invalid status %d", c->c_status);
557 			break;
558 		}
559 
560 	contouch(s);
561 }
562 
563 static void
564 conloop(void)
565 {
566 	struct timeval seltime, now;
567 	fd_set *r, *e;
568 	con *c;
569 	int i;
570 
571 	monotime_tv(&now);
572 	c = TAILQ_FIRST(&tq);
573 
574 	if (c && timercmp(&c->c_tv, &now, >))
575 		timersub(&c->c_tv, &now, &seltime);
576 	else
577 		timerclear(&seltime);
578 
579 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
580 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
581 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
582 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
583 
584 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
585 	    (errno == EAGAIN || errno == EINTR))
586 		;
587 
588 	for (i = 0; i < maxfd; i++) {
589 		if (FD_ISSET(i, e)) {
590 			error("%s: exception!", fdcon[i].c_name);
591 			confree(i);
592 		} else if (FD_ISSET(i, r))
593 			conread(i);
594 	}
595 	free(r);
596 	free(e);
597 
598 	c = TAILQ_FIRST(&tq);
599 	while (c && timercmp(&c->c_tv, &now, <)) {
600 		int s = c->c_fd;
601 
602 		c = TAILQ_NEXT(c, c_link);
603 		conrecycle(s);
604 	}
605 }
606 
607 static void
608 do_host(char *host)
609 {
610 	char *name = strnnsep(&host, " \t\n");
611 	int j;
612 
613 	if (name == NULL)
614 		return;
615 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
616 		if (get_keytypes & j) {
617 			while (ncon >= MAXCON)
618 				conloop();
619 			conalloc(name, *host ? host : name, j);
620 		}
621 	}
622 }
623 
624 void
625 sshfatal(const char *file, const char *func, int line, int showfunc,
626     LogLevel level, const char *suffix, const char *fmt, ...)
627 {
628 	va_list args;
629 
630 	va_start(args, fmt);
631 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
632 	va_end(args);
633 	cleanup_exit(255);
634 }
635 
636 __dead static void
637 usage(void)
638 {
639 	fprintf(stderr,
640 	    "usage: %s [-46cDHv] [-f file] [-p port] [-T timeout] [-t type]\n"
641 	    "\t\t   [host | addrlist namelist]\n",
642 	    __progname);
643 	exit(1);
644 }
645 
646 int
647 main(int argc, char **argv)
648 {
649 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
650 	int opt, fopt_count = 0, j;
651 	char *tname, *cp, *line = NULL;
652 	size_t linesize = 0;
653 	FILE *fp;
654 
655 	extern int optind;
656 	extern char *optarg;
657 
658 	TAILQ_INIT(&tq);
659 
660 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
661 	sanitise_stdfd();
662 
663 	if (argc <= 1)
664 		usage();
665 
666 	while ((opt = getopt(argc, argv, "cDHv46p:T:t:f:")) != -1) {
667 		switch (opt) {
668 		case 'H':
669 			hash_hosts = 1;
670 			break;
671 		case 'c':
672 			get_cert = 1;
673 			break;
674 		case 'D':
675 			print_sshfp = 1;
676 			break;
677 		case 'p':
678 			ssh_port = a2port(optarg);
679 			if (ssh_port <= 0) {
680 				fprintf(stderr, "Bad port '%s'\n", optarg);
681 				exit(1);
682 			}
683 			break;
684 		case 'T':
685 			timeout = convtime(optarg);
686 			if (timeout == -1 || timeout == 0) {
687 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
688 				usage();
689 			}
690 			break;
691 		case 'v':
692 			if (!debug_flag) {
693 				debug_flag = 1;
694 				log_level = SYSLOG_LEVEL_DEBUG1;
695 			}
696 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
697 				log_level++;
698 			else
699 				fatal("Too high debugging level.");
700 			break;
701 		case 'f':
702 			if (strcmp(optarg, "-") == 0)
703 				optarg = NULL;
704 			argv[fopt_count++] = optarg;
705 			break;
706 		case 't':
707 			get_keytypes = 0;
708 			tname = strtok(optarg, ",");
709 			while (tname) {
710 				int type = sshkey_type_from_name(tname);
711 
712 				switch (type) {
713 				case KEY_DSA:
714 					get_keytypes |= KT_DSA;
715 					break;
716 				case KEY_ECDSA:
717 					get_keytypes |= KT_ECDSA;
718 					break;
719 				case KEY_RSA:
720 					get_keytypes |= KT_RSA;
721 					break;
722 				case KEY_ED25519:
723 					get_keytypes |= KT_ED25519;
724 					break;
725 				case KEY_XMSS:
726 					get_keytypes |= KT_XMSS;
727 					break;
728 				case KEY_ED25519_SK:
729 					get_keytypes |= KT_ED25519_SK;
730 					break;
731 				case KEY_ECDSA_SK:
732 					get_keytypes |= KT_ECDSA_SK;
733 					break;
734 				case KEY_UNSPEC:
735 				default:
736 					fatal("Unknown key type \"%s\"", tname);
737 				}
738 				tname = strtok(NULL, ",");
739 			}
740 			break;
741 		case '4':
742 			IPv4or6 = AF_INET;
743 			break;
744 		case '6':
745 			IPv4or6 = AF_INET6;
746 			break;
747 		case '?':
748 		default:
749 			usage();
750 		}
751 	}
752 	if (optind == argc && !fopt_count)
753 		usage();
754 
755 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
756 
757 	maxfd = fdlim_get(1);
758 	if (maxfd < 0)
759 		fatal("%s: fdlim_get: bad value", __progname);
760 	if (maxfd > MAXMAXFD)
761 		maxfd = MAXMAXFD;
762 	if (MAXCON <= 0)
763 		fatal("%s: not enough file descriptors", __progname);
764 	if (maxfd > fdlim_get(0))
765 		fdlim_set(maxfd);
766 	fdcon = xcalloc(maxfd, sizeof(con));
767 
768 	read_wait_nfdset = howmany(maxfd, NFDBITS);
769 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
770 
771 	for (j = 0; j < fopt_count; j++) {
772 		if (argv[j] == NULL)
773 			fp = stdin;
774 		else if ((fp = fopen(argv[j], "r")) == NULL)
775 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
776 
777 		while (getline(&line, &linesize, fp) != -1) {
778 			/* Chomp off trailing whitespace and comments */
779 			if ((cp = strchr(line, '#')) == NULL)
780 				cp = line + strlen(line) - 1;
781 			while (cp >= line) {
782 				if (*cp == ' ' || *cp == '\t' ||
783 				    *cp == '\n' || *cp == '#')
784 					*cp-- = '\0';
785 				else
786 					break;
787 			}
788 
789 			/* Skip empty lines */
790 			if (*line == '\0')
791 				continue;
792 
793 			do_host(line);
794 		}
795 
796 		if (ferror(fp))
797 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
798 
799 		fclose(fp);
800 	}
801 	free(line);
802 
803 	while (optind < argc)
804 		do_host(argv[optind++]);
805 
806 	while (ncon > 0)
807 		conloop();
808 
809 	return found_one ? 0 : 1;
810 }
811