xref: /openbsd-src/usr.bin/ssh/ssh-keyscan.c (revision cb39b41371628601fbe4c618205356d538b9d08a)
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 <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 #include <openssl/bn.h>
17 
18 #include <errno.h>
19 #include <netdb.h>
20 #include <stdarg.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <signal.h>
24 #include <string.h>
25 #include <unistd.h>
26 
27 #include "xmalloc.h"
28 #include "ssh.h"
29 #include "ssh1.h"
30 #include "sshbuf.h"
31 #include "sshkey.h"
32 #include "cipher.h"
33 #include "kex.h"
34 #include "compat.h"
35 #include "myproposal.h"
36 #include "packet.h"
37 #include "dispatch.h"
38 #include "log.h"
39 #include "atomicio.h"
40 #include "misc.h"
41 #include "hostfile.h"
42 #include "ssherr.h"
43 #include "ssh_api.h"
44 
45 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
46    Default value is AF_UNSPEC means both IPv4 and IPv6. */
47 int IPv4or6 = AF_UNSPEC;
48 
49 int ssh_port = SSH_DEFAULT_PORT;
50 
51 #define KT_RSA1		1
52 #define KT_DSA		2
53 #define KT_RSA		4
54 #define KT_ECDSA	8
55 #define KT_ED25519	16
56 
57 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
58 
59 int hash_hosts = 0;		/* Hash hostname on output */
60 
61 #define MAXMAXFD 256
62 
63 /* The number of seconds after which to give up on a TCP connection */
64 int timeout = 5;
65 
66 int maxfd;
67 #define MAXCON (maxfd - 10)
68 
69 extern char *__progname;
70 fd_set *read_wait;
71 size_t read_wait_nfdset;
72 int ncon;
73 
74 /*
75  * Keep a connection structure for each file descriptor.  The state
76  * associated with file descriptor n is held in fdcon[n].
77  */
78 typedef struct Connection {
79 	u_char c_status;	/* State of connection on this file desc. */
80 #define CS_UNUSED 0		/* File descriptor unused */
81 #define CS_CON 1		/* Waiting to connect/read greeting */
82 #define CS_SIZE 2		/* Waiting to read initial packet size */
83 #define CS_KEYS 3		/* Waiting to read public key packet */
84 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
85 	int c_plen;		/* Packet length field for ssh packet */
86 	int c_len;		/* Total bytes which must be read. */
87 	int c_off;		/* Length of data read so far. */
88 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
89 	sig_atomic_t c_done;	/* SSH2 done */
90 	char *c_namebase;	/* Address to free for c_name and c_namelist */
91 	char *c_name;		/* Hostname of connection for errors */
92 	char *c_namelist;	/* Pointer to other possible addresses */
93 	char *c_output_name;	/* Hostname of connection for output */
94 	char *c_data;		/* Data read from this fd */
95 	struct ssh *c_ssh;	/* SSH-connection */
96 	struct timeval c_tv;	/* Time at which connection gets aborted */
97 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
98 } con;
99 
100 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
101 con *fdcon;
102 
103 static void keyprint(con *c, struct sshkey *key);
104 
105 static int
106 fdlim_get(int hard)
107 {
108 	struct rlimit rlfd;
109 
110 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
111 		return (-1);
112 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
113 		return sysconf(_SC_OPEN_MAX);
114 	else
115 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
116 }
117 
118 static int
119 fdlim_set(int lim)
120 {
121 	struct rlimit rlfd;
122 
123 	if (lim <= 0)
124 		return (-1);
125 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
126 		return (-1);
127 	rlfd.rlim_cur = lim;
128 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
129 		return (-1);
130 	return (0);
131 }
132 
133 /*
134  * This is an strsep function that returns a null field for adjacent
135  * separators.  This is the same as the 4.4BSD strsep, but different from the
136  * one in the GNU libc.
137  */
138 static char *
139 xstrsep(char **str, const char *delim)
140 {
141 	char *s, *e;
142 
143 	if (!**str)
144 		return (NULL);
145 
146 	s = *str;
147 	e = s + strcspn(s, delim);
148 
149 	if (*e != '\0')
150 		*e++ = '\0';
151 	*str = e;
152 
153 	return (s);
154 }
155 
156 /*
157  * Get the next non-null token (like GNU strsep).  Strsep() will return a
158  * null token for two adjacent separators, so we may have to loop.
159  */
160 static char *
161 strnnsep(char **stringp, char *delim)
162 {
163 	char *tok;
164 
165 	do {
166 		tok = xstrsep(stringp, delim);
167 	} while (tok && *tok == '\0');
168 	return (tok);
169 }
170 
171 #ifdef WITH_SSH1
172 static struct sshkey *
173 keygrab_ssh1(con *c)
174 {
175 	static struct sshkey *rsa;
176 	static struct sshbuf *msg;
177 	int r;
178 	u_char type;
179 
180 	if (rsa == NULL) {
181 		if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
182 			error("%s: sshkey_new failed", __func__);
183 			return NULL;
184 		}
185 		if ((msg = sshbuf_new()) == NULL)
186 			fatal("%s: sshbuf_new failed", __func__);
187 	}
188 	if ((r = sshbuf_put(msg, c->c_data, c->c_plen)) != 0 ||
189 	    (r = sshbuf_consume(msg, 8 - (c->c_plen & 7))) != 0 || /* padding */
190 	    (r = sshbuf_get_u8(msg, &type)) != 0)
191 		goto buf_err;
192 	if (type != (int) SSH_SMSG_PUBLIC_KEY) {
193 		error("%s: invalid packet type", c->c_name);
194 		sshbuf_reset(msg);
195 		return NULL;
196 	}
197 	if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
198 	    /* server key */
199 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
200 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
201 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
202 	    /* host key */
203 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
204 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->e)) != 0 ||
205 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->n)) != 0) {
206  buf_err:
207 		error("%s: buffer error: %s", __func__, ssh_err(r));
208 		sshbuf_reset(msg);
209 		return NULL;
210 	}
211 
212 	sshbuf_reset(msg);
213 
214 	return (rsa);
215 }
216 #endif
217 
218 static int
219 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
220 {
221 	con *c;
222 
223 	if ((c = ssh_get_app_data(ssh)) != NULL)
224 		keyprint(c, hostkey);
225 	/* always abort key exchange */
226 	return -1;
227 }
228 
229 static int
230 ssh2_capable(int remote_major, int remote_minor)
231 {
232 	switch (remote_major) {
233 	case 1:
234 		if (remote_minor == 99)
235 			return 1;
236 		break;
237 	case 2:
238 		return 1;
239 	default:
240 		break;
241 	}
242 	return 0;
243 }
244 
245 static void
246 keygrab_ssh2(con *c)
247 {
248 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
249 	int r;
250 
251 	enable_compat20();
252 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
253 	    c->c_keytype == KT_DSA ?  "ssh-dss" :
254 	    (c->c_keytype == KT_RSA ? "ssh-rsa" :
255 	    (c->c_keytype == KT_ED25519 ? "ssh-ed25519" :
256 	    "ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521"));
257 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
258 		free(c->c_ssh);
259 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
260 		exit(1);
261 	}
262 #ifdef WITH_OPENSSL
263 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
264 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
265 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
266 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
267 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
268 #endif
269 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
270 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
271 	/*
272 	 * do the key-exchange until an error occurs or until
273 	 * the key_print_wrapper() callback sets c_done.
274 	 */
275 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
276 }
277 
278 static void
279 keyprint(con *c, struct sshkey *key)
280 {
281 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
282 	char *hostport = NULL;
283 
284 	if (!key)
285 		return;
286 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
287 		fatal("host_hash failed");
288 
289 	hostport = put_host_port(host, ssh_port);
290 	fprintf(stdout, "%s ", hostport);
291 	sshkey_write(key, stdout);
292 	fputs("\n", stdout);
293 	free(hostport);
294 }
295 
296 static int
297 tcpconnect(char *host)
298 {
299 	struct addrinfo hints, *ai, *aitop;
300 	char strport[NI_MAXSERV];
301 	int gaierr, s = -1;
302 
303 	snprintf(strport, sizeof strport, "%d", ssh_port);
304 	memset(&hints, 0, sizeof(hints));
305 	hints.ai_family = IPv4or6;
306 	hints.ai_socktype = SOCK_STREAM;
307 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
308 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
309 		return -1;
310 	}
311 	for (ai = aitop; ai; ai = ai->ai_next) {
312 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
313 		if (s < 0) {
314 			error("socket: %s", strerror(errno));
315 			continue;
316 		}
317 		if (set_nonblock(s) == -1)
318 			fatal("%s: set_nonblock(%d)", __func__, s);
319 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
320 		    errno != EINPROGRESS)
321 			error("connect (`%s'): %s", host, strerror(errno));
322 		else
323 			break;
324 		close(s);
325 		s = -1;
326 	}
327 	freeaddrinfo(aitop);
328 	return s;
329 }
330 
331 static int
332 conalloc(char *iname, char *oname, int keytype)
333 {
334 	char *namebase, *name, *namelist;
335 	int s;
336 
337 	namebase = namelist = xstrdup(iname);
338 
339 	do {
340 		name = xstrsep(&namelist, ",");
341 		if (!name) {
342 			free(namebase);
343 			return (-1);
344 		}
345 	} while ((s = tcpconnect(name)) < 0);
346 
347 	if (s >= maxfd)
348 		fatal("conalloc: fdno %d too high", s);
349 	if (fdcon[s].c_status)
350 		fatal("conalloc: attempt to reuse fdno %d", s);
351 
352 	fdcon[s].c_fd = s;
353 	fdcon[s].c_status = CS_CON;
354 	fdcon[s].c_namebase = namebase;
355 	fdcon[s].c_name = name;
356 	fdcon[s].c_namelist = namelist;
357 	fdcon[s].c_output_name = xstrdup(oname);
358 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
359 	fdcon[s].c_len = 4;
360 	fdcon[s].c_off = 0;
361 	fdcon[s].c_keytype = keytype;
362 	gettimeofday(&fdcon[s].c_tv, NULL);
363 	fdcon[s].c_tv.tv_sec += timeout;
364 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
365 	FD_SET(s, read_wait);
366 	ncon++;
367 	return (s);
368 }
369 
370 static void
371 confree(int s)
372 {
373 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
374 		fatal("confree: attempt to free bad fdno %d", s);
375 	close(s);
376 	free(fdcon[s].c_namebase);
377 	free(fdcon[s].c_output_name);
378 	if (fdcon[s].c_status == CS_KEYS)
379 		free(fdcon[s].c_data);
380 	fdcon[s].c_status = CS_UNUSED;
381 	fdcon[s].c_keytype = 0;
382 	if (fdcon[s].c_ssh) {
383 		ssh_packet_close(fdcon[s].c_ssh);
384 		free(fdcon[s].c_ssh);
385 		fdcon[s].c_ssh = NULL;
386 	}
387 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
388 	FD_CLR(s, read_wait);
389 	ncon--;
390 }
391 
392 static void
393 contouch(int s)
394 {
395 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
396 	gettimeofday(&fdcon[s].c_tv, NULL);
397 	fdcon[s].c_tv.tv_sec += timeout;
398 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
399 }
400 
401 static int
402 conrecycle(int s)
403 {
404 	con *c = &fdcon[s];
405 	int ret;
406 
407 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
408 	confree(s);
409 	return (ret);
410 }
411 
412 static void
413 congreet(int s)
414 {
415 	int n = 0, remote_major = 0, remote_minor = 0;
416 	char buf[256], *cp;
417 	char remote_version[sizeof buf];
418 	size_t bufsiz;
419 	con *c = &fdcon[s];
420 
421 	for (;;) {
422 		memset(buf, '\0', sizeof(buf));
423 		bufsiz = sizeof(buf);
424 		cp = buf;
425 		while (bufsiz-- &&
426 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
427 			if (*cp == '\r')
428 				*cp = '\n';
429 			cp++;
430 		}
431 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
432 			break;
433 	}
434 	if (n == 0) {
435 		switch (errno) {
436 		case EPIPE:
437 			error("%s: Connection closed by remote host", c->c_name);
438 			break;
439 		case ECONNREFUSED:
440 			break;
441 		default:
442 			error("read (%s): %s", c->c_name, strerror(errno));
443 			break;
444 		}
445 		conrecycle(s);
446 		return;
447 	}
448 	if (*cp != '\n' && *cp != '\r') {
449 		error("%s: bad greeting", c->c_name);
450 		confree(s);
451 		return;
452 	}
453 	*cp = '\0';
454 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
455 		fatal("ssh_packet_set_connection failed");
456 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
457 	ssh_set_app_data(c->c_ssh, c);	/* back link */
458 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
459 	    &remote_major, &remote_minor, remote_version) == 3)
460 		c->c_ssh->compat = compat_datafellows(remote_version);
461 	else
462 		c->c_ssh->compat = 0;
463 	if (c->c_keytype != KT_RSA1) {
464 		if (!ssh2_capable(remote_major, remote_minor)) {
465 			debug("%s doesn't support ssh2", c->c_name);
466 			confree(s);
467 			return;
468 		}
469 	} else if (remote_major != 1) {
470 		debug("%s doesn't support ssh1", c->c_name);
471 		confree(s);
472 		return;
473 	}
474 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
475 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
476 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
477 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
478 	if (n < 0 || (size_t)n >= sizeof(buf)) {
479 		error("snprintf: buffer too small");
480 		confree(s);
481 		return;
482 	}
483 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
484 		error("write (%s): %s", c->c_name, strerror(errno));
485 		confree(s);
486 		return;
487 	}
488 	if (c->c_keytype != KT_RSA1) {
489 		keygrab_ssh2(c);
490 		confree(s);
491 		return;
492 	}
493 	c->c_status = CS_SIZE;
494 	contouch(s);
495 }
496 
497 static void
498 conread(int s)
499 {
500 	con *c = &fdcon[s];
501 	size_t n;
502 
503 	if (c->c_status == CS_CON) {
504 		congreet(s);
505 		return;
506 	}
507 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
508 	if (n == 0) {
509 		error("read (%s): %s", c->c_name, strerror(errno));
510 		confree(s);
511 		return;
512 	}
513 	c->c_off += n;
514 
515 	if (c->c_off == c->c_len)
516 		switch (c->c_status) {
517 		case CS_SIZE:
518 			c->c_plen = htonl(c->c_plen);
519 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
520 			c->c_off = 0;
521 			c->c_data = xmalloc(c->c_len);
522 			c->c_status = CS_KEYS;
523 			break;
524 #ifdef WITH_SSH1
525 		case CS_KEYS:
526 			keyprint(c, keygrab_ssh1(c));
527 			confree(s);
528 			return;
529 #endif
530 		default:
531 			fatal("conread: invalid status %d", c->c_status);
532 			break;
533 		}
534 
535 	contouch(s);
536 }
537 
538 static void
539 conloop(void)
540 {
541 	struct timeval seltime, now;
542 	fd_set *r, *e;
543 	con *c;
544 	int i;
545 
546 	gettimeofday(&now, NULL);
547 	c = TAILQ_FIRST(&tq);
548 
549 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
550 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
551 		seltime = c->c_tv;
552 		seltime.tv_sec -= now.tv_sec;
553 		seltime.tv_usec -= now.tv_usec;
554 		if (seltime.tv_usec < 0) {
555 			seltime.tv_usec += 1000000;
556 			seltime.tv_sec--;
557 		}
558 	} else
559 		timerclear(&seltime);
560 
561 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
562 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
563 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
564 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
565 
566 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
567 	    (errno == EAGAIN || errno == EINTR))
568 		;
569 
570 	for (i = 0; i < maxfd; i++) {
571 		if (FD_ISSET(i, e)) {
572 			error("%s: exception!", fdcon[i].c_name);
573 			confree(i);
574 		} else if (FD_ISSET(i, r))
575 			conread(i);
576 	}
577 	free(r);
578 	free(e);
579 
580 	c = TAILQ_FIRST(&tq);
581 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
582 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
583 		int s = c->c_fd;
584 
585 		c = TAILQ_NEXT(c, c_link);
586 		conrecycle(s);
587 	}
588 }
589 
590 static void
591 do_host(char *host)
592 {
593 	char *name = strnnsep(&host, " \t\n");
594 	int j;
595 
596 	if (name == NULL)
597 		return;
598 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
599 		if (get_keytypes & j) {
600 			while (ncon >= MAXCON)
601 				conloop();
602 			conalloc(name, *host ? host : name, j);
603 		}
604 	}
605 }
606 
607 void
608 fatal(const char *fmt,...)
609 {
610 	va_list args;
611 
612 	va_start(args, fmt);
613 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
614 	va_end(args);
615 	exit(255);
616 }
617 
618 static void
619 usage(void)
620 {
621 	fprintf(stderr,
622 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
623 	    "\t\t   [host | addrlist namelist] ...\n",
624 	    __progname);
625 	exit(1);
626 }
627 
628 int
629 main(int argc, char **argv)
630 {
631 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
632 	int opt, fopt_count = 0, j;
633 	char *tname, *cp, line[NI_MAXHOST];
634 	FILE *fp;
635 	u_long linenum;
636 
637 	extern int optind;
638 	extern char *optarg;
639 
640 	TAILQ_INIT(&tq);
641 
642 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
643 	sanitise_stdfd();
644 
645 	if (argc <= 1)
646 		usage();
647 
648 	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
649 		switch (opt) {
650 		case 'H':
651 			hash_hosts = 1;
652 			break;
653 		case 'p':
654 			ssh_port = a2port(optarg);
655 			if (ssh_port <= 0) {
656 				fprintf(stderr, "Bad port '%s'\n", optarg);
657 				exit(1);
658 			}
659 			break;
660 		case 'T':
661 			timeout = convtime(optarg);
662 			if (timeout == -1 || timeout == 0) {
663 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
664 				usage();
665 			}
666 			break;
667 		case 'v':
668 			if (!debug_flag) {
669 				debug_flag = 1;
670 				log_level = SYSLOG_LEVEL_DEBUG1;
671 			}
672 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
673 				log_level++;
674 			else
675 				fatal("Too high debugging level.");
676 			break;
677 		case 'f':
678 			if (strcmp(optarg, "-") == 0)
679 				optarg = NULL;
680 			argv[fopt_count++] = optarg;
681 			break;
682 		case 't':
683 			get_keytypes = 0;
684 			tname = strtok(optarg, ",");
685 			while (tname) {
686 				int type = sshkey_type_from_name(tname);
687 				switch (type) {
688 				case KEY_RSA1:
689 					get_keytypes |= KT_RSA1;
690 					break;
691 				case KEY_DSA:
692 					get_keytypes |= KT_DSA;
693 					break;
694 				case KEY_ECDSA:
695 					get_keytypes |= KT_ECDSA;
696 					break;
697 				case KEY_RSA:
698 					get_keytypes |= KT_RSA;
699 					break;
700 				case KEY_ED25519:
701 					get_keytypes |= KT_ED25519;
702 					break;
703 				case KEY_UNSPEC:
704 					fatal("unknown key type %s", tname);
705 				}
706 				tname = strtok(NULL, ",");
707 			}
708 			break;
709 		case '4':
710 			IPv4or6 = AF_INET;
711 			break;
712 		case '6':
713 			IPv4or6 = AF_INET6;
714 			break;
715 		case '?':
716 		default:
717 			usage();
718 		}
719 	}
720 	if (optind == argc && !fopt_count)
721 		usage();
722 
723 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
724 
725 	maxfd = fdlim_get(1);
726 	if (maxfd < 0)
727 		fatal("%s: fdlim_get: bad value", __progname);
728 	if (maxfd > MAXMAXFD)
729 		maxfd = MAXMAXFD;
730 	if (MAXCON <= 0)
731 		fatal("%s: not enough file descriptors", __progname);
732 	if (maxfd > fdlim_get(0))
733 		fdlim_set(maxfd);
734 	fdcon = xcalloc(maxfd, sizeof(con));
735 
736 	read_wait_nfdset = howmany(maxfd, NFDBITS);
737 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
738 
739 	for (j = 0; j < fopt_count; j++) {
740 		if (argv[j] == NULL)
741 			fp = stdin;
742 		else if ((fp = fopen(argv[j], "r")) == NULL)
743 			fatal("%s: %s: %s", __progname, argv[j],
744 			    strerror(errno));
745 		linenum = 0;
746 
747 		while (read_keyfile_line(fp,
748 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
749 		    &linenum) != -1) {
750 			/* Chomp off trailing whitespace and comments */
751 			if ((cp = strchr(line, '#')) == NULL)
752 				cp = line + strlen(line) - 1;
753 			while (cp >= line) {
754 				if (*cp == ' ' || *cp == '\t' ||
755 				    *cp == '\n' || *cp == '#')
756 					*cp-- = '\0';
757 				else
758 					break;
759 			}
760 
761 			/* Skip empty lines */
762 			if (*line == '\0')
763 				continue;
764 
765 			do_host(line);
766 		}
767 
768 		if (ferror(fp))
769 			fatal("%s: %s: %s", __progname, argv[j],
770 			    strerror(errno));
771 
772 		fclose(fp);
773 	}
774 
775 	while (optind < argc)
776 		do_host(argv[optind++]);
777 
778 	while (ncon > 0)
779 		conloop();
780 
781 	return (0);
782 }
783