xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision 946379e7b37692fc43f68eb0d1c10daa0a7f3b6c)
1 /*	$NetBSD: ssh-keyscan.c,v 1.14 2015/07/03 01:00:00 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.101 2015/04/10 00:08:55 djm Exp $ */
3 /*
4  * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
5  *
6  * Modification and redistribution in source and binary forms is
7  * permitted provided that due credit is given to the author and the
8  * OpenBSD project by leaving this copyright notice intact.
9  */
10 
11 #include "includes.h"
12 __RCSID("$NetBSD: ssh-keyscan.c,v 1.14 2015/07/03 01:00:00 christos Exp $");
13 
14 #include <sys/param.h>
15 #include <sys/types.h>
16 #include <sys/socket.h>
17 #include <sys/queue.h>
18 #include <sys/time.h>
19 #include <sys/resource.h>
20 
21 #include <openssl/bn.h>
22 
23 #include <errno.h>
24 #include <netdb.h>
25 #include <stdarg.h>
26 #include <stdio.h>
27 #include <stdlib.h>
28 #include <signal.h>
29 #include <string.h>
30 #include <unistd.h>
31 
32 #include "xmalloc.h"
33 #include "ssh.h"
34 #include "ssh1.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 
50 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
51    Default value is AF_UNSPEC means both IPv4 and IPv6. */
52 int IPv4or6 = AF_UNSPEC;
53 
54 int ssh_port = SSH_DEFAULT_PORT;
55 
56 #define KT_RSA1		1
57 #define KT_DSA		2
58 #define KT_RSA		4
59 #define KT_ECDSA	8
60 #define KT_ED25519	16
61 
62 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
63 
64 int hash_hosts = 0;		/* Hash hostname on output */
65 
66 #define MAXMAXFD 256
67 
68 /* The number of seconds after which to give up on a TCP connection */
69 int timeout = 5;
70 
71 int maxfd;
72 #define MAXCON (maxfd - 10)
73 
74 extern char *__progname;
75 fd_set *read_wait;
76 size_t read_wait_nfdset;
77 int ncon;
78 
79 /*
80  * Keep a connection structure for each file descriptor.  The state
81  * associated with file descriptor n is held in fdcon[n].
82  */
83 typedef struct Connection {
84 	u_char c_status;	/* State of connection on this file desc. */
85 #define CS_UNUSED 0		/* File descriptor unused */
86 #define CS_CON 1		/* Waiting to connect/read greeting */
87 #define CS_SIZE 2		/* Waiting to read initial packet size */
88 #define CS_KEYS 3		/* Waiting to read public key packet */
89 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
90 	int c_plen;		/* Packet length field for ssh packet */
91 	int c_len;		/* Total bytes which must be read. */
92 	int c_off;		/* Length of data read so far. */
93 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
94 	sig_atomic_t c_done;	/* SSH2 done */
95 	char *c_namebase;	/* Address to free for c_name and c_namelist */
96 	char *c_name;		/* Hostname of connection for errors */
97 	char *c_namelist;	/* Pointer to other possible addresses */
98 	char *c_output_name;	/* Hostname of connection for output */
99 	char *c_data;		/* Data read from this fd */
100 	struct ssh *c_ssh;	/* SSH-connection */
101 	struct timeval c_tv;	/* Time at which connection gets aborted */
102 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
103 } con;
104 
105 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
106 con *fdcon;
107 
108 static void keyprint(con *c, struct sshkey *key);
109 
110 static int
111 fdlim_get(int hard)
112 {
113 	struct rlimit rlfd;
114 
115 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
116 		return (-1);
117 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
118 		return sysconf(_SC_OPEN_MAX);
119 	else
120 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
121 }
122 
123 static int
124 fdlim_set(int lim)
125 {
126 	struct rlimit rlfd;
127 
128 	if (lim <= 0)
129 		return (-1);
130 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
131 		return (-1);
132 	rlfd.rlim_cur = lim;
133 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
134 		return (-1);
135 	return (0);
136 }
137 
138 /*
139  * This is an strsep function that returns a null field for adjacent
140  * separators.  This is the same as the 4.4BSD strsep, but different from the
141  * one in the GNU libc.
142  */
143 static char *
144 xstrsep(char **str, const char *delim)
145 {
146 	char *s, *e;
147 
148 	if (!**str)
149 		return (NULL);
150 
151 	s = *str;
152 	e = s + strcspn(s, delim);
153 
154 	if (*e != '\0')
155 		*e++ = '\0';
156 	*str = e;
157 
158 	return (s);
159 }
160 
161 /*
162  * Get the next non-null token (like GNU strsep).  Strsep() will return a
163  * null token for two adjacent separators, so we may have to loop.
164  */
165 static char *
166 strnnsep(char **stringp, const char *delim)
167 {
168 	char *tok;
169 
170 	do {
171 		tok = xstrsep(stringp, delim);
172 	} while (tok && *tok == '\0');
173 	return (tok);
174 }
175 
176 #ifdef WITH_SSH1
177 static struct sshkey *
178 keygrab_ssh1(con *c)
179 {
180 	static struct sshkey *rsa;
181 	static struct sshbuf *msg;
182 	int r;
183 	u_char type;
184 
185 	if (rsa == NULL) {
186 		if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
187 			error("%s: sshkey_new failed", __func__);
188 			return NULL;
189 		}
190 		if ((msg = sshbuf_new()) == NULL)
191 			fatal("%s: sshbuf_new failed", __func__);
192 	}
193 	if ((r = sshbuf_put(msg, c->c_data, c->c_plen)) != 0 ||
194 	    (r = sshbuf_consume(msg, 8 - (c->c_plen & 7))) != 0 || /* padding */
195 	    (r = sshbuf_get_u8(msg, &type)) != 0)
196 		goto buf_err;
197 	if (type != (int) SSH_SMSG_PUBLIC_KEY) {
198 		error("%s: invalid packet type", c->c_name);
199 		sshbuf_reset(msg);
200 		return NULL;
201 	}
202 	if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
203 	    /* server key */
204 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
205 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
206 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
207 	    /* host key */
208 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
209 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->e)) != 0 ||
210 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->n)) != 0) {
211  buf_err:
212 		error("%s: buffer error: %s", __func__, ssh_err(r));
213 		sshbuf_reset(msg);
214 		return NULL;
215 	}
216 
217 	sshbuf_reset(msg);
218 
219 	return (rsa);
220 }
221 #endif
222 
223 static int
224 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
225 {
226 	con *c;
227 
228 	if ((c = ssh_get_app_data(ssh)) != NULL)
229 		keyprint(c, hostkey);
230 	/* always abort key exchange */
231 	return -1;
232 }
233 
234 static int
235 ssh2_capable(int remote_major, int remote_minor)
236 {
237 	switch (remote_major) {
238 	case 1:
239 		if (remote_minor == 99)
240 			return 1;
241 		break;
242 	case 2:
243 		return 1;
244 	default:
245 		break;
246 	}
247 	return 0;
248 }
249 
250 static void
251 keygrab_ssh2(con *c)
252 {
253 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
254 	int r;
255 
256 	enable_compat20();
257 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
258 	    c->c_keytype == KT_DSA ?  "ssh-dss" :
259 	    (c->c_keytype == KT_RSA ? "ssh-rsa" :
260 	    (c->c_keytype == KT_ED25519 ? "ssh-ed25519" :
261 	    "ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521"));
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] = kexdh_client;
269 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = 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 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
273 #endif
274 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
275 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
276 	/*
277 	 * do the key-exchange until an error occurs or until
278 	 * the key_print_wrapper() callback sets c_done.
279 	 */
280 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
281 }
282 
283 static void
284 keyprint(con *c, struct sshkey *key)
285 {
286 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
287 	int r;
288 	char *hostport = NULL;
289 
290 	if (!key)
291 		return;
292 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
293 		fatal("host_hash failed");
294 
295 	hostport = put_host_port(host, ssh_port);
296 	fprintf(stdout, "%s ", hostport);
297 
298 	if ((r = sshkey_write(key, stdout)) != 0)
299 		fprintf(stderr, "key_write failed: %s", ssh_err(r));
300 
301 	fputs("\n", stdout);
302 	free(hostport);
303 }
304 
305 static int
306 tcpconnect(char *host)
307 {
308 	struct addrinfo hints, *ai, *aitop;
309 	char strport[NI_MAXSERV];
310 	int gaierr, s = -1;
311 
312 	snprintf(strport, sizeof strport, "%d", ssh_port);
313 	memset(&hints, 0, sizeof(hints));
314 	hints.ai_family = IPv4or6;
315 	hints.ai_socktype = SOCK_STREAM;
316 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
317 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
318 		return -1;
319 	}
320 	for (ai = aitop; ai; ai = ai->ai_next) {
321 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
322 		if (s < 0) {
323 			error("socket: %s", strerror(errno));
324 			continue;
325 		}
326 		if (set_nonblock(s) == -1)
327 			fatal("%s: set_nonblock(%d)", __func__, s);
328 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
329 		    errno != EINPROGRESS)
330 			error("connect (`%s'): %s", host, strerror(errno));
331 		else
332 			break;
333 		close(s);
334 		s = -1;
335 	}
336 	freeaddrinfo(aitop);
337 	return s;
338 }
339 
340 static int
341 conalloc(char *iname, char *oname, int keytype)
342 {
343 	char *namebase, *name, *namelist;
344 	int s;
345 
346 	namebase = namelist = xstrdup(iname);
347 
348 	do {
349 		name = xstrsep(&namelist, ",");
350 		if (!name) {
351 			free(namebase);
352 			return (-1);
353 		}
354 	} while ((s = tcpconnect(name)) < 0);
355 
356 	if (s >= maxfd)
357 		fatal("conalloc: fdno %d too high", s);
358 	if (fdcon[s].c_status)
359 		fatal("conalloc: attempt to reuse fdno %d", s);
360 
361 	fdcon[s].c_fd = s;
362 	fdcon[s].c_status = CS_CON;
363 	fdcon[s].c_namebase = namebase;
364 	fdcon[s].c_name = name;
365 	fdcon[s].c_namelist = namelist;
366 	fdcon[s].c_output_name = xstrdup(oname);
367 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
368 	fdcon[s].c_len = 4;
369 	fdcon[s].c_off = 0;
370 	fdcon[s].c_keytype = keytype;
371 	gettimeofday(&fdcon[s].c_tv, NULL);
372 	fdcon[s].c_tv.tv_sec += timeout;
373 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
374 	FD_SET(s, read_wait);
375 	ncon++;
376 	return (s);
377 }
378 
379 static void
380 confree(int s)
381 {
382 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
383 		fatal("confree: attempt to free bad fdno %d", s);
384 	close(s);
385 	free(fdcon[s].c_namebase);
386 	free(fdcon[s].c_output_name);
387 	if (fdcon[s].c_status == CS_KEYS)
388 		free(fdcon[s].c_data);
389 	fdcon[s].c_status = CS_UNUSED;
390 	fdcon[s].c_keytype = 0;
391 	if (fdcon[s].c_ssh) {
392 		ssh_packet_close(fdcon[s].c_ssh);
393 		free(fdcon[s].c_ssh);
394 		fdcon[s].c_ssh = NULL;
395 	}
396 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
397 	FD_CLR(s, read_wait);
398 	ncon--;
399 }
400 
401 static void
402 contouch(int s)
403 {
404 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
405 	gettimeofday(&fdcon[s].c_tv, NULL);
406 	fdcon[s].c_tv.tv_sec += timeout;
407 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
408 }
409 
410 static int
411 conrecycle(int s)
412 {
413 	con *c = &fdcon[s];
414 	int ret;
415 
416 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
417 	confree(s);
418 	return (ret);
419 }
420 
421 static void
422 congreet(int s)
423 {
424 	int n = 0, remote_major = 0, remote_minor = 0;
425 	char buf[256], *cp;
426 	char remote_version[sizeof buf];
427 	size_t bufsiz;
428 	con *c = &fdcon[s];
429 
430 	for (;;) {
431 		memset(buf, '\0', sizeof(buf));
432 		bufsiz = sizeof(buf);
433 		cp = buf;
434 		while (bufsiz-- &&
435 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
436 			if (*cp == '\r')
437 				*cp = '\n';
438 			cp++;
439 		}
440 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
441 			break;
442 	}
443 	if (n == 0) {
444 		switch (errno) {
445 		case EPIPE:
446 			error("%s: Connection closed by remote host", c->c_name);
447 			break;
448 		case ECONNREFUSED:
449 			break;
450 		default:
451 			error("read (%s): %s", c->c_name, strerror(errno));
452 			break;
453 		}
454 		conrecycle(s);
455 		return;
456 	}
457 	if (*cp != '\n' && *cp != '\r') {
458 		error("%s: bad greeting", c->c_name);
459 		confree(s);
460 		return;
461 	}
462 	*cp = '\0';
463 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
464 		fatal("ssh_packet_set_connection failed");
465 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
466 	ssh_set_app_data(c->c_ssh, c);	/* back link */
467 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
468 	    &remote_major, &remote_minor, remote_version) == 3)
469 		c->c_ssh->compat = compat_datafellows(remote_version);
470 	else
471 		c->c_ssh->compat = 0;
472 	if (c->c_keytype != KT_RSA1) {
473 		if (!ssh2_capable(remote_major, remote_minor)) {
474 			debug("%s doesn't support ssh2", c->c_name);
475 			confree(s);
476 			return;
477 		}
478 	} else if (remote_major != 1) {
479 		debug("%s doesn't support ssh1", c->c_name);
480 		confree(s);
481 		return;
482 	}
483 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
484 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
485 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
486 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
487 	if (n < 0 || (size_t)n >= sizeof(buf)) {
488 		error("snprintf: buffer too small");
489 		confree(s);
490 		return;
491 	}
492 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
493 		error("write (%s): %s", c->c_name, strerror(errno));
494 		confree(s);
495 		return;
496 	}
497 	if (c->c_keytype != KT_RSA1) {
498 		keygrab_ssh2(c);
499 		confree(s);
500 		return;
501 	}
502 	c->c_status = CS_SIZE;
503 	contouch(s);
504 }
505 
506 static void
507 conread(int s)
508 {
509 	con *c = &fdcon[s];
510 	size_t n;
511 
512 	if (c->c_status == CS_CON) {
513 		congreet(s);
514 		return;
515 	}
516 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
517 	if (n == 0) {
518 		error("read (%s): %s", c->c_name, strerror(errno));
519 		confree(s);
520 		return;
521 	}
522 	c->c_off += n;
523 
524 	if (c->c_off == c->c_len)
525 		switch (c->c_status) {
526 		case CS_SIZE:
527 			c->c_plen = htonl(c->c_plen);
528 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
529 			c->c_off = 0;
530 			c->c_data = xmalloc(c->c_len);
531 			c->c_status = CS_KEYS;
532 			break;
533 #ifdef WITH_SSH1
534 		case CS_KEYS:
535 			keyprint(c, keygrab_ssh1(c));
536 			confree(s);
537 			return;
538 #endif
539 		default:
540 			fatal("conread: invalid status %d", c->c_status);
541 			break;
542 		}
543 
544 	contouch(s);
545 }
546 
547 static void
548 conloop(void)
549 {
550 	struct timeval seltime, now;
551 	fd_set *r, *e;
552 	con *c;
553 	int i;
554 
555 	gettimeofday(&now, NULL);
556 	c = TAILQ_FIRST(&tq);
557 
558 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
559 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
560 		seltime = c->c_tv;
561 		seltime.tv_sec -= now.tv_sec;
562 		seltime.tv_usec -= now.tv_usec;
563 		if (seltime.tv_usec < 0) {
564 			seltime.tv_usec += 1000000;
565 			seltime.tv_sec--;
566 		}
567 	} else
568 		timerclear(&seltime);
569 
570 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
571 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
572 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
573 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
574 
575 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
576 	    (errno == EAGAIN || errno == EINTR))
577 		;
578 
579 	for (i = 0; i < maxfd; i++) {
580 		if (FD_ISSET(i, e)) {
581 			error("%s: exception!", fdcon[i].c_name);
582 			confree(i);
583 		} else if (FD_ISSET(i, r))
584 			conread(i);
585 	}
586 	free(r);
587 	free(e);
588 
589 	c = TAILQ_FIRST(&tq);
590 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
591 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
592 		int s = c->c_fd;
593 
594 		c = TAILQ_NEXT(c, c_link);
595 		conrecycle(s);
596 	}
597 }
598 
599 static void
600 do_host(char *host)
601 {
602 	char *name = strnnsep(&host, " \t\n");
603 	int j;
604 
605 	if (name == NULL)
606 		return;
607 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
608 		if (get_keytypes & j) {
609 			while (ncon >= MAXCON)
610 				conloop();
611 			conalloc(name, *host ? host : name, j);
612 		}
613 	}
614 }
615 
616 __dead void
617 fatal(const char *fmt,...)
618 {
619 	va_list args;
620 
621 	va_start(args, fmt);
622 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
623 	va_end(args);
624 	exit(255);
625 }
626 
627 __dead static void
628 usage(void)
629 {
630 	fprintf(stderr,
631 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
632 	    "\t\t   [host | addrlist namelist] ...\n",
633 	    __progname);
634 	exit(1);
635 }
636 
637 int
638 main(int argc, char **argv)
639 {
640 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
641 	int opt, fopt_count = 0, j;
642 	char *tname, *cp, line[NI_MAXHOST];
643 	FILE *fp;
644 	u_long linenum;
645 
646 	extern int optind;
647 	extern char *optarg;
648 
649 	TAILQ_INIT(&tq);
650 
651 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
652 	sanitise_stdfd();
653 
654 	if (argc <= 1)
655 		usage();
656 
657 	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
658 		switch (opt) {
659 		case 'H':
660 			hash_hosts = 1;
661 			break;
662 		case 'p':
663 			ssh_port = a2port(optarg);
664 			if (ssh_port <= 0) {
665 				fprintf(stderr, "Bad port '%s'\n", optarg);
666 				exit(1);
667 			}
668 			break;
669 		case 'T':
670 			timeout = convtime(optarg);
671 			if (timeout == -1 || timeout == 0) {
672 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
673 				usage();
674 			}
675 			break;
676 		case 'v':
677 			if (!debug_flag) {
678 				debug_flag = 1;
679 				log_level = SYSLOG_LEVEL_DEBUG1;
680 			}
681 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
682 				log_level++;
683 			else
684 				fatal("Too high debugging level.");
685 			break;
686 		case 'f':
687 			if (strcmp(optarg, "-") == 0)
688 				optarg = NULL;
689 			argv[fopt_count++] = optarg;
690 			break;
691 		case 't':
692 			get_keytypes = 0;
693 			tname = strtok(optarg, ",");
694 			while (tname) {
695 				int type = sshkey_type_from_name(tname);
696 				switch (type) {
697 				case KEY_RSA1:
698 					get_keytypes |= KT_RSA1;
699 					break;
700 				case KEY_DSA:
701 					get_keytypes |= KT_DSA;
702 					break;
703 				case KEY_ECDSA:
704 					get_keytypes |= KT_ECDSA;
705 					break;
706 				case KEY_RSA:
707 					get_keytypes |= KT_RSA;
708 					break;
709 				case KEY_ED25519:
710 					get_keytypes |= KT_ED25519;
711 					break;
712 				case KEY_UNSPEC:
713 					fatal("unknown key type %s", tname);
714 				}
715 				tname = strtok(NULL, ",");
716 			}
717 			break;
718 		case '4':
719 			IPv4or6 = AF_INET;
720 			break;
721 		case '6':
722 			IPv4or6 = AF_INET6;
723 			break;
724 		case '?':
725 		default:
726 			usage();
727 		}
728 	}
729 	if (optind == argc && !fopt_count)
730 		usage();
731 
732 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
733 
734 	maxfd = fdlim_get(1);
735 	if (maxfd < 0)
736 		fatal("%s: fdlim_get: bad value", __progname);
737 	if (maxfd > MAXMAXFD)
738 		maxfd = MAXMAXFD;
739 	if (MAXCON <= 0)
740 		fatal("%s: not enough file descriptors", __progname);
741 	if (maxfd > fdlim_get(0))
742 		fdlim_set(maxfd);
743 	fdcon = xcalloc(maxfd, sizeof(con));
744 
745 	read_wait_nfdset = howmany(maxfd, NFDBITS);
746 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
747 
748 	for (j = 0; j < fopt_count; j++) {
749 		if (argv[j] == NULL)
750 			fp = stdin;
751 		else if ((fp = fopen(argv[j], "r")) == NULL)
752 			fatal("%s: %s: %s", __progname, argv[j],
753 			    strerror(errno));
754 		linenum = 0;
755 
756 		while (read_keyfile_line(fp,
757 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
758 		    &linenum) != -1) {
759 			/* Chomp off trailing whitespace and comments */
760 			if ((cp = strchr(line, '#')) == NULL)
761 				cp = line + strlen(line) - 1;
762 			while (cp >= line) {
763 				if (*cp == ' ' || *cp == '\t' ||
764 				    *cp == '\n' || *cp == '#')
765 					*cp-- = '\0';
766 				else
767 					break;
768 			}
769 
770 			/* Skip empty lines */
771 			if (*line == '\0')
772 				continue;
773 
774 			do_host(line);
775 		}
776 
777 		if (ferror(fp))
778 			fatal("%s: %s: %s", __progname, argv[j],
779 			    strerror(errno));
780 
781 		fclose(fp);
782 	}
783 
784 	while (optind < argc)
785 		do_host(argv[optind++]);
786 
787 	while (ncon > 0)
788 		conloop();
789 
790 	return (0);
791 }
792