xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision 1f4bcc459a76b7aa664f3fd557684cd0ba6da352)
1 /* $OpenBSD: ssh-keyscan.c,v 1.101 2015/04/10 00:08:55 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 "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 "ssh1.h"
36 #include "sshbuf.h"
37 #include "sshkey.h"
38 #include "cipher.h"
39 #include "kex.h"
40 #include "compat.h"
41 #include "myproposal.h"
42 #include "packet.h"
43 #include "dispatch.h"
44 #include "log.h"
45 #include "atomicio.h"
46 #include "misc.h"
47 #include "hostfile.h"
48 #include "ssherr.h"
49 #include "ssh_api.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_RSA1		1
58 #define KT_DSA		2
59 #define KT_RSA		4
60 #define KT_ECDSA	8
61 #define KT_ED25519	16
62 
63 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
64 
65 int hash_hosts = 0;		/* Hash hostname on output */
66 
67 #define MAXMAXFD 256
68 
69 /* The number of seconds after which to give up on a TCP connection */
70 int timeout = 5;
71 
72 int maxfd;
73 #define MAXCON (maxfd - 10)
74 
75 extern char *__progname;
76 fd_set *read_wait;
77 size_t read_wait_nfdset;
78 int ncon;
79 
80 struct ssh *active_state = NULL; /* XXX needed for linking */
81 
82 /*
83  * Keep a connection structure for each file descriptor.  The state
84  * associated with file descriptor n is held in fdcon[n].
85  */
86 typedef struct Connection {
87 	u_char c_status;	/* State of connection on this file desc. */
88 #define CS_UNUSED 0		/* File descriptor unused */
89 #define CS_CON 1		/* Waiting to connect/read greeting */
90 #define CS_SIZE 2		/* Waiting to read initial packet size */
91 #define CS_KEYS 3		/* Waiting to read public key packet */
92 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
93 	int c_plen;		/* Packet length field for ssh packet */
94 	int c_len;		/* Total bytes which must be read. */
95 	int c_off;		/* Length of data read so far. */
96 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
97 	sig_atomic_t c_done;	/* SSH2 done */
98 	char *c_namebase;	/* Address to free for c_name and c_namelist */
99 	char *c_name;		/* Hostname of connection for errors */
100 	char *c_namelist;	/* Pointer to other possible addresses */
101 	char *c_output_name;	/* Hostname of connection for output */
102 	char *c_data;		/* Data read from this fd */
103 	struct ssh *c_ssh;	/* SSH-connection */
104 	struct timeval c_tv;	/* Time at which connection gets aborted */
105 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
106 } con;
107 
108 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
109 con *fdcon;
110 
111 static void keyprint(con *c, struct sshkey *key);
112 
113 static int
114 fdlim_get(int hard)
115 {
116 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
117 	struct rlimit rlfd;
118 
119 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
120 		return (-1);
121 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
122 		return SSH_SYSFDMAX;
123 	else
124 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
125 #else
126 	return SSH_SYSFDMAX;
127 #endif
128 }
129 
130 static int
131 fdlim_set(int lim)
132 {
133 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
134 	struct rlimit rlfd;
135 #endif
136 
137 	if (lim <= 0)
138 		return (-1);
139 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
140 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
141 		return (-1);
142 	rlfd.rlim_cur = lim;
143 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
144 		return (-1);
145 #elif defined (HAVE_SETDTABLESIZE)
146 	setdtablesize(lim);
147 #endif
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, 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 #ifdef WITH_SSH1
190 static struct sshkey *
191 keygrab_ssh1(con *c)
192 {
193 	static struct sshkey *rsa;
194 	static struct sshbuf *msg;
195 	int r;
196 	u_char type;
197 
198 	if (rsa == NULL) {
199 		if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
200 			error("%s: sshkey_new failed", __func__);
201 			return NULL;
202 		}
203 		if ((msg = sshbuf_new()) == NULL)
204 			fatal("%s: sshbuf_new failed", __func__);
205 	}
206 	if ((r = sshbuf_put(msg, c->c_data, c->c_plen)) != 0 ||
207 	    (r = sshbuf_consume(msg, 8 - (c->c_plen & 7))) != 0 || /* padding */
208 	    (r = sshbuf_get_u8(msg, &type)) != 0)
209 		goto buf_err;
210 	if (type != (int) SSH_SMSG_PUBLIC_KEY) {
211 		error("%s: invalid packet type", c->c_name);
212 		sshbuf_reset(msg);
213 		return NULL;
214 	}
215 	if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
216 	    /* server key */
217 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
218 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
219 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
220 	    /* host key */
221 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
222 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->e)) != 0 ||
223 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->n)) != 0) {
224  buf_err:
225 		error("%s: buffer error: %s", __func__, ssh_err(r));
226 		sshbuf_reset(msg);
227 		return NULL;
228 	}
229 
230 	sshbuf_reset(msg);
231 
232 	return (rsa);
233 }
234 #endif
235 
236 static int
237 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
238 {
239 	con *c;
240 
241 	if ((c = ssh_get_app_data(ssh)) != NULL)
242 		keyprint(c, hostkey);
243 	/* always abort key exchange */
244 	return -1;
245 }
246 
247 static int
248 ssh2_capable(int remote_major, int remote_minor)
249 {
250 	switch (remote_major) {
251 	case 1:
252 		if (remote_minor == 99)
253 			return 1;
254 		break;
255 	case 2:
256 		return 1;
257 	default:
258 		break;
259 	}
260 	return 0;
261 }
262 
263 static void
264 keygrab_ssh2(con *c)
265 {
266 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
267 	int r;
268 
269 	enable_compat20();
270 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
271 	    c->c_keytype == KT_DSA ?  "ssh-dss" :
272 	    (c->c_keytype == KT_RSA ? "ssh-rsa" :
273 	    (c->c_keytype == KT_ED25519 ? "ssh-ed25519" :
274 	    "ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521"));
275 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
276 		free(c->c_ssh);
277 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
278 		exit(1);
279 	}
280 #ifdef WITH_OPENSSL
281 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
282 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
283 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
284 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
285 # ifdef OPENSSL_HAS_ECC
286 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
287 # endif
288 #endif
289 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
290 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
291 	/*
292 	 * do the key-exchange until an error occurs or until
293 	 * the key_print_wrapper() callback sets c_done.
294 	 */
295 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
296 }
297 
298 static void
299 keyprint(con *c, struct sshkey *key)
300 {
301 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
302 	char *hostport = NULL;
303 
304 	if (!key)
305 		return;
306 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
307 		fatal("host_hash failed");
308 
309 	hostport = put_host_port(host, ssh_port);
310 	fprintf(stdout, "%s ", hostport);
311 	sshkey_write(key, stdout);
312 	fputs("\n", stdout);
313 	free(hostport);
314 }
315 
316 static int
317 tcpconnect(char *host)
318 {
319 	struct addrinfo hints, *ai, *aitop;
320 	char strport[NI_MAXSERV];
321 	int gaierr, s = -1;
322 
323 	snprintf(strport, sizeof strport, "%d", ssh_port);
324 	memset(&hints, 0, sizeof(hints));
325 	hints.ai_family = IPv4or6;
326 	hints.ai_socktype = SOCK_STREAM;
327 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
328 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
329 		return -1;
330 	}
331 	for (ai = aitop; ai; ai = ai->ai_next) {
332 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
333 		if (s < 0) {
334 			error("socket: %s", strerror(errno));
335 			continue;
336 		}
337 		if (set_nonblock(s) == -1)
338 			fatal("%s: set_nonblock(%d)", __func__, s);
339 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
340 		    errno != EINPROGRESS)
341 			error("connect (`%s'): %s", host, strerror(errno));
342 		else
343 			break;
344 		close(s);
345 		s = -1;
346 	}
347 	freeaddrinfo(aitop);
348 	return s;
349 }
350 
351 static int
352 conalloc(char *iname, char *oname, int keytype)
353 {
354 	char *namebase, *name, *namelist;
355 	int s;
356 
357 	namebase = namelist = xstrdup(iname);
358 
359 	do {
360 		name = xstrsep(&namelist, ",");
361 		if (!name) {
362 			free(namebase);
363 			return (-1);
364 		}
365 	} while ((s = tcpconnect(name)) < 0);
366 
367 	if (s >= maxfd)
368 		fatal("conalloc: fdno %d too high", s);
369 	if (fdcon[s].c_status)
370 		fatal("conalloc: attempt to reuse fdno %d", s);
371 
372 	fdcon[s].c_fd = s;
373 	fdcon[s].c_status = CS_CON;
374 	fdcon[s].c_namebase = namebase;
375 	fdcon[s].c_name = name;
376 	fdcon[s].c_namelist = namelist;
377 	fdcon[s].c_output_name = xstrdup(oname);
378 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
379 	fdcon[s].c_len = 4;
380 	fdcon[s].c_off = 0;
381 	fdcon[s].c_keytype = keytype;
382 	gettimeofday(&fdcon[s].c_tv, NULL);
383 	fdcon[s].c_tv.tv_sec += timeout;
384 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
385 	FD_SET(s, read_wait);
386 	ncon++;
387 	return (s);
388 }
389 
390 static void
391 confree(int s)
392 {
393 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
394 		fatal("confree: attempt to free bad fdno %d", s);
395 	close(s);
396 	free(fdcon[s].c_namebase);
397 	free(fdcon[s].c_output_name);
398 	if (fdcon[s].c_status == CS_KEYS)
399 		free(fdcon[s].c_data);
400 	fdcon[s].c_status = CS_UNUSED;
401 	fdcon[s].c_keytype = 0;
402 	if (fdcon[s].c_ssh) {
403 		ssh_packet_close(fdcon[s].c_ssh);
404 		free(fdcon[s].c_ssh);
405 		fdcon[s].c_ssh = NULL;
406 	}
407 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
408 	FD_CLR(s, read_wait);
409 	ncon--;
410 }
411 
412 static void
413 contouch(int s)
414 {
415 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
416 	gettimeofday(&fdcon[s].c_tv, NULL);
417 	fdcon[s].c_tv.tv_sec += timeout;
418 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
419 }
420 
421 static int
422 conrecycle(int s)
423 {
424 	con *c = &fdcon[s];
425 	int ret;
426 
427 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
428 	confree(s);
429 	return (ret);
430 }
431 
432 static void
433 congreet(int s)
434 {
435 	int n = 0, remote_major = 0, remote_minor = 0;
436 	char buf[256], *cp;
437 	char remote_version[sizeof buf];
438 	size_t bufsiz;
439 	con *c = &fdcon[s];
440 
441 	for (;;) {
442 		memset(buf, '\0', sizeof(buf));
443 		bufsiz = sizeof(buf);
444 		cp = buf;
445 		while (bufsiz-- &&
446 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
447 			if (*cp == '\r')
448 				*cp = '\n';
449 			cp++;
450 		}
451 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
452 			break;
453 	}
454 	if (n == 0) {
455 		switch (errno) {
456 		case EPIPE:
457 			error("%s: Connection closed by remote host", c->c_name);
458 			break;
459 		case ECONNREFUSED:
460 			break;
461 		default:
462 			error("read (%s): %s", c->c_name, strerror(errno));
463 			break;
464 		}
465 		conrecycle(s);
466 		return;
467 	}
468 	if (*cp != '\n' && *cp != '\r') {
469 		error("%s: bad greeting", c->c_name);
470 		confree(s);
471 		return;
472 	}
473 	*cp = '\0';
474 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
475 		fatal("ssh_packet_set_connection failed");
476 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
477 	ssh_set_app_data(c->c_ssh, c);	/* back link */
478 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
479 	    &remote_major, &remote_minor, remote_version) == 3)
480 		c->c_ssh->compat = compat_datafellows(remote_version);
481 	else
482 		c->c_ssh->compat = 0;
483 	if (c->c_keytype != KT_RSA1) {
484 		if (!ssh2_capable(remote_major, remote_minor)) {
485 			debug("%s doesn't support ssh2", c->c_name);
486 			confree(s);
487 			return;
488 		}
489 	} else if (remote_major != 1) {
490 		debug("%s doesn't support ssh1", c->c_name);
491 		confree(s);
492 		return;
493 	}
494 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
495 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
496 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
497 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
498 	if (n < 0 || (size_t)n >= sizeof(buf)) {
499 		error("snprintf: buffer too small");
500 		confree(s);
501 		return;
502 	}
503 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
504 		error("write (%s): %s", c->c_name, strerror(errno));
505 		confree(s);
506 		return;
507 	}
508 	if (c->c_keytype != KT_RSA1) {
509 		keygrab_ssh2(c);
510 		confree(s);
511 		return;
512 	}
513 	c->c_status = CS_SIZE;
514 	contouch(s);
515 }
516 
517 static void
518 conread(int s)
519 {
520 	con *c = &fdcon[s];
521 	size_t n;
522 
523 	if (c->c_status == CS_CON) {
524 		congreet(s);
525 		return;
526 	}
527 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
528 	if (n == 0) {
529 		error("read (%s): %s", c->c_name, strerror(errno));
530 		confree(s);
531 		return;
532 	}
533 	c->c_off += n;
534 
535 	if (c->c_off == c->c_len)
536 		switch (c->c_status) {
537 		case CS_SIZE:
538 			c->c_plen = htonl(c->c_plen);
539 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
540 			c->c_off = 0;
541 			c->c_data = xmalloc(c->c_len);
542 			c->c_status = CS_KEYS;
543 			break;
544 #ifdef WITH_SSH1
545 		case CS_KEYS:
546 			keyprint(c, keygrab_ssh1(c));
547 			confree(s);
548 			return;
549 #endif
550 		default:
551 			fatal("conread: invalid status %d", c->c_status);
552 			break;
553 		}
554 
555 	contouch(s);
556 }
557 
558 static void
559 conloop(void)
560 {
561 	struct timeval seltime, now;
562 	fd_set *r, *e;
563 	con *c;
564 	int i;
565 
566 	gettimeofday(&now, NULL);
567 	c = TAILQ_FIRST(&tq);
568 
569 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
570 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
571 		seltime = c->c_tv;
572 		seltime.tv_sec -= now.tv_sec;
573 		seltime.tv_usec -= now.tv_usec;
574 		if (seltime.tv_usec < 0) {
575 			seltime.tv_usec += 1000000;
576 			seltime.tv_sec--;
577 		}
578 	} else
579 		timerclear(&seltime);
580 
581 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
582 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
583 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
584 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
585 
586 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
587 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
588 		;
589 
590 	for (i = 0; i < maxfd; i++) {
591 		if (FD_ISSET(i, e)) {
592 			error("%s: exception!", fdcon[i].c_name);
593 			confree(i);
594 		} else if (FD_ISSET(i, r))
595 			conread(i);
596 	}
597 	free(r);
598 	free(e);
599 
600 	c = TAILQ_FIRST(&tq);
601 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
602 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
603 		int s = c->c_fd;
604 
605 		c = TAILQ_NEXT(c, c_link);
606 		conrecycle(s);
607 	}
608 }
609 
610 static void
611 do_host(char *host)
612 {
613 	char *name = strnnsep(&host, " \t\n");
614 	int j;
615 
616 	if (name == NULL)
617 		return;
618 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
619 		if (get_keytypes & j) {
620 			while (ncon >= MAXCON)
621 				conloop();
622 			conalloc(name, *host ? host : name, j);
623 		}
624 	}
625 }
626 
627 void
628 fatal(const char *fmt,...)
629 {
630 	va_list args;
631 
632 	va_start(args, fmt);
633 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
634 	va_end(args);
635 	exit(255);
636 }
637 
638 static void
639 usage(void)
640 {
641 	fprintf(stderr,
642 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
643 	    "\t\t   [host | addrlist namelist] ...\n",
644 	    __progname);
645 	exit(1);
646 }
647 
648 int
649 main(int argc, char **argv)
650 {
651 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
652 	int opt, fopt_count = 0, j;
653 	char *tname, *cp, line[NI_MAXHOST];
654 	FILE *fp;
655 	u_long linenum;
656 
657 	extern int optind;
658 	extern char *optarg;
659 
660 	__progname = ssh_get_progname(argv[0]);
661 	seed_rng();
662 	TAILQ_INIT(&tq);
663 
664 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
665 	sanitise_stdfd();
666 
667 	if (argc <= 1)
668 		usage();
669 
670 	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
671 		switch (opt) {
672 		case 'H':
673 			hash_hosts = 1;
674 			break;
675 		case 'p':
676 			ssh_port = a2port(optarg);
677 			if (ssh_port <= 0) {
678 				fprintf(stderr, "Bad port '%s'\n", optarg);
679 				exit(1);
680 			}
681 			break;
682 		case 'T':
683 			timeout = convtime(optarg);
684 			if (timeout == -1 || timeout == 0) {
685 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
686 				usage();
687 			}
688 			break;
689 		case 'v':
690 			if (!debug_flag) {
691 				debug_flag = 1;
692 				log_level = SYSLOG_LEVEL_DEBUG1;
693 			}
694 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
695 				log_level++;
696 			else
697 				fatal("Too high debugging level.");
698 			break;
699 		case 'f':
700 			if (strcmp(optarg, "-") == 0)
701 				optarg = NULL;
702 			argv[fopt_count++] = optarg;
703 			break;
704 		case 't':
705 			get_keytypes = 0;
706 			tname = strtok(optarg, ",");
707 			while (tname) {
708 				int type = sshkey_type_from_name(tname);
709 				switch (type) {
710 				case KEY_RSA1:
711 					get_keytypes |= KT_RSA1;
712 					break;
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_UNSPEC:
726 					fatal("unknown key type %s", tname);
727 				}
728 				tname = strtok(NULL, ",");
729 			}
730 			break;
731 		case '4':
732 			IPv4or6 = AF_INET;
733 			break;
734 		case '6':
735 			IPv4or6 = AF_INET6;
736 			break;
737 		case '?':
738 		default:
739 			usage();
740 		}
741 	}
742 	if (optind == argc && !fopt_count)
743 		usage();
744 
745 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
746 
747 	maxfd = fdlim_get(1);
748 	if (maxfd < 0)
749 		fatal("%s: fdlim_get: bad value", __progname);
750 	if (maxfd > MAXMAXFD)
751 		maxfd = MAXMAXFD;
752 	if (MAXCON <= 0)
753 		fatal("%s: not enough file descriptors", __progname);
754 	if (maxfd > fdlim_get(0))
755 		fdlim_set(maxfd);
756 	fdcon = xcalloc(maxfd, sizeof(con));
757 
758 	read_wait_nfdset = howmany(maxfd, NFDBITS);
759 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
760 
761 	for (j = 0; j < fopt_count; j++) {
762 		if (argv[j] == NULL)
763 			fp = stdin;
764 		else if ((fp = fopen(argv[j], "r")) == NULL)
765 			fatal("%s: %s: %s", __progname, argv[j],
766 			    strerror(errno));
767 		linenum = 0;
768 
769 		while (read_keyfile_line(fp,
770 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
771 		    &linenum) != -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],
792 			    strerror(errno));
793 
794 		fclose(fp);
795 	}
796 
797 	while (optind < argc)
798 		do_host(argv[optind++]);
799 
800 	while (ncon > 0)
801 		conloop();
802 
803 	return (0);
804 }
805