xref: /openbsd-src/usr.bin/ssh/ssh-keyscan.c (revision 7c0ec4b8992567abb1e1536622dc789a9a39d9f1) 
1 /* $OpenBSD: ssh-keyscan.c,v 1.160 2024/09/04 05:33:34 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 <limits.h>
22 #include <netdb.h>
23 #include <stdarg.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <poll.h>
27 #include <signal.h>
28 #include <string.h>
29 #include <unistd.h>
30 
31 #include "xmalloc.h"
32 #include "ssh.h"
33 #include "sshbuf.h"
34 #include "sshkey.h"
35 #include "cipher.h"
36 #include "digest.h"
37 #include "kex.h"
38 #include "compat.h"
39 #include "myproposal.h"
40 #include "packet.h"
41 #include "dispatch.h"
42 #include "log.h"
43 #include "atomicio.h"
44 #include "misc.h"
45 #include "hostfile.h"
46 #include "ssherr.h"
47 #include "ssh_api.h"
48 #include "dns.h"
49 #include "addr.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 #define KT_ECDSA_SK	(1<<5)
63 #define KT_ED25519_SK	(1<<6)
64 
65 #define KT_MIN		KT_DSA
66 #define KT_MAX		KT_ED25519_SK
67 
68 int get_cert = 0;
69 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
70 
71 int hash_hosts = 0;		/* Hash hostname on output */
72 
73 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
74 
75 int found_one = 0;		/* Successfully found a key */
76 
77 int hashalg = -1;		/* Hash for SSHFP records or -1 for all */
78 
79 int quiet = 0;			/* Don't print key comment lines */
80 
81 #define MAXMAXFD 256
82 
83 /* The number of seconds after which to give up on a TCP connection */
84 int timeout = 5;
85 
86 int maxfd;
87 #define MAXCON (maxfd - 10)
88 
89 extern char *__progname;
90 struct pollfd *read_wait;
91 int ncon;
92 
93 /*
94  * Keep a connection structure for each file descriptor.  The state
95  * associated with file descriptor n is held in fdcon[n].
96  */
97 typedef struct Connection {
98 	u_char c_status;	/* State of connection on this file desc. */
99 #define CS_UNUSED 0		/* File descriptor unused */
100 #define CS_CON 1		/* Waiting to connect/read greeting */
101 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
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 	struct ssh *c_ssh;	/* SSH-connection */
109 	struct timespec c_ts;	/* Time at which connection gets aborted */
110 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
111 } con;
112 
113 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
114 con *fdcon;
115 
116 static void keyprint(con *c, struct sshkey *key);
117 
118 static int
119 fdlim_get(int hard)
120 {
121 	struct rlimit rlfd;
122 
123 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
124 		return (-1);
125 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY ||
126 	    (hard ? rlfd.rlim_max : rlfd.rlim_cur) > INT_MAX)
127 		return sysconf(_SC_OPEN_MAX);
128 	return hard ? rlfd.rlim_max : rlfd.rlim_cur;
129 }
130 
131 static int
132 fdlim_set(int lim)
133 {
134 	struct rlimit rlfd;
135 
136 	if (lim <= 0)
137 		return (-1);
138 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
139 		return (-1);
140 	rlfd.rlim_cur = lim;
141 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
142 		return (-1);
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 *
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 *
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 
185 static int
186 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
187 {
188 	con *c;
189 
190 	if ((c = ssh_get_app_data(ssh)) != NULL)
191 		keyprint(c, hostkey);
192 	/* always abort key exchange */
193 	return -1;
194 }
195 
196 static int
197 ssh2_capable(int remote_major, int remote_minor)
198 {
199 	switch (remote_major) {
200 	case 1:
201 		if (remote_minor == 99)
202 			return 1;
203 		break;
204 	case 2:
205 		return 1;
206 	default:
207 		break;
208 	}
209 	return 0;
210 }
211 
212 static void
213 keygrab_ssh2(con *c)
214 {
215 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
216 	int r;
217 
218 	switch (c->c_keytype) {
219 	case KT_DSA:
220 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
221 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
222 		break;
223 	case KT_RSA:
224 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
225 		    "rsa-sha2-512-cert-v01@openssh.com,"
226 		    "rsa-sha2-256-cert-v01@openssh.com,"
227 		    "ssh-rsa-cert-v01@openssh.com" :
228 		    "rsa-sha2-512,"
229 		    "rsa-sha2-256,"
230 		    "ssh-rsa";
231 		break;
232 	case KT_ED25519:
233 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
234 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
235 		break;
236 	case KT_XMSS:
237 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
238 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
239 		break;
240 	case KT_ECDSA:
241 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
242 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
243 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
244 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
245 		    "ecdsa-sha2-nistp256,"
246 		    "ecdsa-sha2-nistp384,"
247 		    "ecdsa-sha2-nistp521";
248 		break;
249 	case KT_ECDSA_SK:
250 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
251 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
252 		    "sk-ecdsa-sha2-nistp256@openssh.com";
253 		break;
254 	case KT_ED25519_SK:
255 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
256 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
257 		    "sk-ssh-ed25519@openssh.com";
258 		break;
259 	default:
260 		fatal("unknown key type %d", c->c_keytype);
261 		break;
262 	}
263 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
264 		free(c->c_ssh);
265 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
266 		exit(1);
267 	}
268 #ifdef WITH_OPENSSL
269 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
270 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
271 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
272 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
273 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
274 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
275 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
276 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
277 #endif
278 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
279 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
280 #ifdef WITH_MLKEM
281 	c->c_ssh->kex->kex[KEX_KEM_MLKEM768X25519_SHA256] = kex_gen_client;
282 #endif
283 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
284 	/*
285 	 * do the key-exchange until an error occurs or until
286 	 * the key_print_wrapper() callback sets c_done.
287 	 */
288 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
289 }
290 
291 static void
292 keyprint_one(const char *host, struct sshkey *key)
293 {
294 	char *hostport = NULL, *hashed = NULL;
295 	const char *known_host;
296 	int r = 0;
297 
298 	found_one = 1;
299 
300 	if (print_sshfp) {
301 		export_dns_rr(host, key, stdout, 0, hashalg);
302 		return;
303 	}
304 
305 	hostport = put_host_port(host, ssh_port);
306 	lowercase(hostport);
307 	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
308 		fatal("host_hash failed");
309 	known_host = hash_hosts ? hashed : hostport;
310 	if (!get_cert)
311 		r = fprintf(stdout, "%s ", known_host);
312 	if (r >= 0 && sshkey_write(key, stdout) == 0)
313 		(void)fputs("\n", stdout);
314 	free(hashed);
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(const char *iname, const 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_keytype = keytype;
400 	monotime_ts(&fdcon[s].c_ts);
401 	fdcon[s].c_ts.tv_sec += timeout;
402 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
403 	read_wait[s].fd = s;
404 	read_wait[s].events = POLLIN;
405 	ncon++;
406 	return (s);
407 }
408 
409 static void
410 confree(int s)
411 {
412 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
413 		fatal("confree: attempt to free bad fdno %d", s);
414 	free(fdcon[s].c_namebase);
415 	free(fdcon[s].c_output_name);
416 	fdcon[s].c_status = CS_UNUSED;
417 	fdcon[s].c_keytype = 0;
418 	if (fdcon[s].c_ssh) {
419 		ssh_packet_close(fdcon[s].c_ssh);
420 		free(fdcon[s].c_ssh);
421 		fdcon[s].c_ssh = NULL;
422 	} else
423 		close(s);
424 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
425 	read_wait[s].fd = -1;
426 	read_wait[s].events = 0;
427 	ncon--;
428 }
429 
430 static int
431 conrecycle(int s)
432 {
433 	con *c = &fdcon[s];
434 	int ret;
435 
436 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
437 	confree(s);
438 	return (ret);
439 }
440 
441 static void
442 congreet(int s)
443 {
444 	int n = 0, remote_major = 0, remote_minor = 0;
445 	char buf[256], *cp;
446 	char remote_version[sizeof buf];
447 	size_t bufsiz;
448 	con *c = &fdcon[s];
449 
450 	/* send client banner */
451 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
452 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
453 	if (n < 0 || (size_t)n >= sizeof(buf)) {
454 		error("snprintf: buffer too small");
455 		confree(s);
456 		return;
457 	}
458 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
459 		error("write (%s): %s", c->c_name, strerror(errno));
460 		confree(s);
461 		return;
462 	}
463 
464 	/*
465 	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
466 	 * protocol identification string may be preceded by an arbitrarily
467 	 * large banner which we must read and ignore.  Loop while reading
468 	 * newline-terminated lines until we have one starting with "SSH-".
469 	 * The ID string cannot be longer than 255 characters although the
470 	 * preceding banner lines may (in which case they'll be discarded
471 	 * in multiple iterations of the outer loop).
472 	 */
473 	for (;;) {
474 		memset(buf, '\0', sizeof(buf));
475 		bufsiz = sizeof(buf);
476 		cp = buf;
477 		while (bufsiz-- &&
478 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
479 			if (*cp == '\r')
480 				*cp = '\n';
481 			cp++;
482 		}
483 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
484 			break;
485 	}
486 	if (n == 0) {
487 		switch (errno) {
488 		case EPIPE:
489 			error("%s: Connection closed by remote host", c->c_name);
490 			break;
491 		case ECONNREFUSED:
492 			break;
493 		default:
494 			error("read (%s): %s", c->c_name, strerror(errno));
495 			break;
496 		}
497 		conrecycle(s);
498 		return;
499 	}
500 	if (cp >= buf + sizeof(buf)) {
501 		error("%s: greeting exceeds allowable length", c->c_name);
502 		confree(s);
503 		return;
504 	}
505 	if (*cp != '\n' && *cp != '\r') {
506 		error("%s: bad greeting", c->c_name);
507 		confree(s);
508 		return;
509 	}
510 	*cp = '\0';
511 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
512 		fatal("ssh_packet_set_connection failed");
513 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
514 	ssh_set_app_data(c->c_ssh, c);	/* back link */
515 	c->c_ssh->compat = 0;
516 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
517 	    &remote_major, &remote_minor, remote_version) == 3)
518 		compat_banner(c->c_ssh, remote_version);
519 	if (!ssh2_capable(remote_major, remote_minor)) {
520 		debug("%s doesn't support ssh2", c->c_name);
521 		confree(s);
522 		return;
523 	}
524 	if (!quiet) {
525 		fprintf(stdout, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
526 		    c->c_name, ssh_port, chop(buf));
527 	}
528 	keygrab_ssh2(c);
529 	confree(s);
530 }
531 
532 static void
533 conread(int s)
534 {
535 	con *c = &fdcon[s];
536 
537 	if (c->c_status != CS_CON)
538 		fatal("conread: invalid status %d", c->c_status);
539 
540 	congreet(s);
541 }
542 
543 static void
544 conloop(void)
545 {
546 	struct timespec seltime, now;
547 	con *c;
548 	int i;
549 
550 	monotime_ts(&now);
551 	c = TAILQ_FIRST(&tq);
552 
553 	if (c && timespeccmp(&c->c_ts, &now, >))
554 		timespecsub(&c->c_ts, &now, &seltime);
555 	else
556 		timespecclear(&seltime);
557 
558 	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
559 		if (errno == EAGAIN || errno == EINTR)
560 			continue;
561 		error("poll error");
562 	}
563 
564 	for (i = 0; i < maxfd; i++) {
565 		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
566 			confree(i);
567 		else if (read_wait[i].revents & (POLLIN|POLLHUP))
568 			conread(i);
569 	}
570 
571 	c = TAILQ_FIRST(&tq);
572 	while (c && timespeccmp(&c->c_ts, &now, <)) {
573 		int s = c->c_fd;
574 
575 		c = TAILQ_NEXT(c, c_link);
576 		conrecycle(s);
577 	}
578 }
579 
580 static void
581 do_one_host(char *host)
582 {
583 	char *name = strnnsep(&host, " \t\n");
584 	int j;
585 
586 	if (name == NULL)
587 		return;
588 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
589 		if (get_keytypes & j) {
590 			while (ncon >= MAXCON)
591 				conloop();
592 			conalloc(name, *host ? host : name, j);
593 		}
594 	}
595 }
596 
597 static void
598 do_host(char *host)
599 {
600 	char daddr[128];
601 	struct xaddr addr, end_addr;
602 	u_int masklen;
603 
604 	if (host == NULL)
605 		return;
606 	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
607 		/* Assume argument is a hostname */
608 		do_one_host(host);
609 	} else {
610 		/* Argument is a CIDR range */
611 		debug("CIDR range %s", host);
612 		end_addr = addr;
613 		if (addr_host_to_all1s(&end_addr, masklen) != 0)
614 			goto badaddr;
615 		/*
616 		 * Note: we deliberately include the all-zero/ones addresses.
617 		 */
618 		for (;;) {
619 			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
620  badaddr:
621 				error("Invalid address %s", host);
622 				return;
623 			}
624 			debug("CIDR expand: address %s", daddr);
625 			do_one_host(daddr);
626 			if (addr_cmp(&addr, &end_addr) == 0)
627 				break;
628 			addr_increment(&addr);
629 		};
630 	}
631 }
632 
633 void
634 sshfatal(const char *file, const char *func, int line, int showfunc,
635     LogLevel level, const char *suffix, const char *fmt, ...)
636 {
637 	va_list args;
638 
639 	va_start(args, fmt);
640 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
641 	va_end(args);
642 	cleanup_exit(255);
643 }
644 
645 static void
646 usage(void)
647 {
648 	fprintf(stderr,
649 	    "usage: ssh-keyscan [-46cDHqv] [-f file] [-O option] [-p port] [-T timeout]\n"
650 	    "                   [-t type] [host | addrlist namelist]\n");
651 	exit(1);
652 }
653 
654 int
655 main(int argc, char **argv)
656 {
657 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
658 	int opt, fopt_count = 0, j;
659 	char *tname, *cp, *line = NULL;
660 	size_t linesize = 0;
661 	FILE *fp;
662 
663 	extern int optind;
664 	extern char *optarg;
665 
666 	TAILQ_INIT(&tq);
667 
668 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
669 	sanitise_stdfd();
670 
671 	if (argc <= 1)
672 		usage();
673 
674 	while ((opt = getopt(argc, argv, "cDHqv46O:p:T:t:f:")) != -1) {
675 		switch (opt) {
676 		case 'H':
677 			hash_hosts = 1;
678 			break;
679 		case 'c':
680 			get_cert = 1;
681 			break;
682 		case 'D':
683 			print_sshfp = 1;
684 			break;
685 		case 'p':
686 			ssh_port = a2port(optarg);
687 			if (ssh_port <= 0) {
688 				fprintf(stderr, "Bad port '%s'\n", optarg);
689 				exit(1);
690 			}
691 			break;
692 		case 'T':
693 			timeout = convtime(optarg);
694 			if (timeout == -1 || timeout == 0) {
695 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
696 				usage();
697 			}
698 			break;
699 		case 'v':
700 			if (!debug_flag) {
701 				debug_flag = 1;
702 				log_level = SYSLOG_LEVEL_DEBUG1;
703 			}
704 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
705 				log_level++;
706 			else
707 				fatal("Too high debugging level.");
708 			break;
709 		case 'q':
710 			quiet = 1;
711 			break;
712 		case 'f':
713 			if (strcmp(optarg, "-") == 0)
714 				optarg = NULL;
715 			argv[fopt_count++] = optarg;
716 			break;
717 		case 'O':
718 			/* Maybe other misc options in the future too */
719 			if (strncmp(optarg, "hashalg=", 8) != 0)
720 				fatal("Unsupported -O option");
721 			if ((hashalg = ssh_digest_alg_by_name(
722 			    optarg + 8)) == -1)
723 				fatal("Unsupported hash algorithm");
724 			break;
725 		case 't':
726 			get_keytypes = 0;
727 			tname = strtok(optarg, ",");
728 			while (tname) {
729 				int type = sshkey_type_from_shortname(tname);
730 
731 				switch (type) {
732 #ifdef WITH_DSA
733 				case KEY_DSA:
734 					get_keytypes |= KT_DSA;
735 					break;
736 #endif
737 				case KEY_ECDSA:
738 					get_keytypes |= KT_ECDSA;
739 					break;
740 				case KEY_RSA:
741 					get_keytypes |= KT_RSA;
742 					break;
743 				case KEY_ED25519:
744 					get_keytypes |= KT_ED25519;
745 					break;
746 				case KEY_XMSS:
747 					get_keytypes |= KT_XMSS;
748 					break;
749 				case KEY_ED25519_SK:
750 					get_keytypes |= KT_ED25519_SK;
751 					break;
752 				case KEY_ECDSA_SK:
753 					get_keytypes |= KT_ECDSA_SK;
754 					break;
755 				case KEY_UNSPEC:
756 				default:
757 					fatal("Unknown key type \"%s\"", tname);
758 				}
759 				tname = strtok(NULL, ",");
760 			}
761 			break;
762 		case '4':
763 			IPv4or6 = AF_INET;
764 			break;
765 		case '6':
766 			IPv4or6 = AF_INET6;
767 			break;
768 		default:
769 			usage();
770 		}
771 	}
772 	if (optind == argc && !fopt_count)
773 		usage();
774 
775 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
776 
777 	maxfd = fdlim_get(1);
778 	if (maxfd < 0)
779 		fatal("%s: fdlim_get: bad value", __progname);
780 	if (maxfd > MAXMAXFD)
781 		maxfd = MAXMAXFD;
782 	if (MAXCON <= 0)
783 		fatal("%s: not enough file descriptors", __progname);
784 	if (maxfd > fdlim_get(0))
785 		fdlim_set(maxfd);
786 	fdcon = xcalloc(maxfd, sizeof(con));
787 	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
788 	for (j = 0; j < maxfd; j++)
789 		read_wait[j].fd = -1;
790 
791 	for (j = 0; j < fopt_count; j++) {
792 		if (argv[j] == NULL)
793 			fp = stdin;
794 		else if ((fp = fopen(argv[j], "r")) == NULL)
795 			fatal("%s: %s: %s", __progname,
796 			    fp == stdin ? "<stdin>" : argv[j], strerror(errno));
797 
798 		while (getline(&line, &linesize, fp) != -1) {
799 			/* Chomp off trailing whitespace and comments */
800 			if ((cp = strchr(line, '#')) == NULL)
801 				cp = line + strlen(line) - 1;
802 			while (cp >= line) {
803 				if (*cp == ' ' || *cp == '\t' ||
804 				    *cp == '\n' || *cp == '#')
805 					*cp-- = '\0';
806 				else
807 					break;
808 			}
809 
810 			/* Skip empty lines */
811 			if (*line == '\0')
812 				continue;
813 
814 			do_host(line);
815 		}
816 
817 		if (ferror(fp))
818 			fatal("%s: %s: %s", __progname,
819 			    fp == stdin ? "<stdin>" : argv[j], strerror(errno));
820 
821 		if (fp != stdin)
822 			fclose(fp);
823 	}
824 	free(line);
825 
826 	while (optind < argc)
827 		do_host(argv[optind++]);
828 
829 	while (ncon > 0)
830 		conloop();
831 
832 	return found_one ? 0 : 1;
833 }
834