xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision 796c32c94f6e154afc9de0f63da35c91bb739b45)
1 /*	$NetBSD: ssh-keyscan.c,v 1.20 2017/10/07 19:39:19 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.115 2017/06/30 04:17:23 dtucker 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 1.20 2017/10/07 19:39:19 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 "sshbuf.h"
35 #include "sshkey.h"
36 #include "cipher.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 
49 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
50    Default value is AF_UNSPEC means both IPv4 and IPv6. */
51 int IPv4or6 = AF_UNSPEC;
52 
53 int ssh_port = SSH_DEFAULT_PORT;
54 
55 #define KT_DSA		(1)
56 #define KT_RSA		(1<<1)
57 #define KT_ECDSA	(1<<2)
58 #define KT_ED25519	(1<<3)
59 
60 #define KT_MIN		KT_DSA
61 #define KT_MAX		KT_ED25519
62 
63 int get_cert = 0;
64 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
65 
66 int hash_hosts = 0;		/* Hash hostname on output */
67 
68 #define MAXMAXFD 256
69 
70 /* The number of seconds after which to give up on a TCP connection */
71 int timeout = 5;
72 
73 int maxfd;
74 #define MAXCON (maxfd - 10)
75 
76 extern char *__progname;
77 fd_set *read_wait;
78 size_t read_wait_nfdset;
79 int ncon;
80 
81 /*
82  * Keep a connection structure for each file descriptor.  The state
83  * associated with file descriptor n is held in fdcon[n].
84  */
85 typedef struct Connection {
86 	u_char c_status;	/* State of connection on this file desc. */
87 #define CS_UNUSED 0		/* File descriptor unused */
88 #define CS_CON 1		/* Waiting to connect/read greeting */
89 #define CS_SIZE 2		/* Waiting to read initial packet size */
90 #define CS_KEYS 3		/* Waiting to read public key packet */
91 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
92 	int c_plen;		/* Packet length field for ssh packet */
93 	int c_len;		/* Total bytes which must be read. */
94 	int c_off;		/* Length of data read so far. */
95 	int c_keytype;		/* Only one of KT_* */
96 	sig_atomic_t c_done;	/* SSH2 done */
97 	char *c_namebase;	/* Address to free for c_name and c_namelist */
98 	char *c_name;		/* Hostname of connection for errors */
99 	char *c_namelist;	/* Pointer to other possible addresses */
100 	char *c_output_name;	/* Hostname of connection for output */
101 	char *c_data;		/* Data read from this fd */
102 	struct ssh *c_ssh;	/* SSH-connection */
103 	struct timeval c_tv;	/* Time at which connection gets aborted */
104 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
105 } con;
106 
107 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
108 con *fdcon;
109 
110 static void keyprint(con *c, struct sshkey *key);
111 
112 static int
113 fdlim_get(int hard)
114 {
115 	struct rlimit rlfd;
116 
117 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
118 		return (-1);
119 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
120 		return sysconf(_SC_OPEN_MAX);
121 	else
122 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
123 }
124 
125 static int
126 fdlim_set(int lim)
127 {
128 	struct rlimit rlfd;
129 
130 	if (lim <= 0)
131 		return (-1);
132 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
133 		return (-1);
134 	rlfd.rlim_cur = lim;
135 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
136 		return (-1);
137 	return (0);
138 }
139 
140 /*
141  * This is an strsep function that returns a null field for adjacent
142  * separators.  This is the same as the 4.4BSD strsep, but different from the
143  * one in the GNU libc.
144  */
145 static char *
146 xstrsep(char **str, const char *delim)
147 {
148 	char *s, *e;
149 
150 	if (!**str)
151 		return (NULL);
152 
153 	s = *str;
154 	e = s + strcspn(s, delim);
155 
156 	if (*e != '\0')
157 		*e++ = '\0';
158 	*str = e;
159 
160 	return (s);
161 }
162 
163 /*
164  * Get the next non-null token (like GNU strsep).  Strsep() will return a
165  * null token for two adjacent separators, so we may have to loop.
166  */
167 static char *
168 strnnsep(char **stringp, const char *delim)
169 {
170 	char *tok;
171 
172 	do {
173 		tok = xstrsep(stringp, delim);
174 	} while (tok && *tok == '\0');
175 	return (tok);
176 }
177 
178 
179 static int
180 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
181 {
182 	con *c;
183 
184 	if ((c = ssh_get_app_data(ssh)) != NULL)
185 		keyprint(c, hostkey);
186 	/* always abort key exchange */
187 	return -1;
188 }
189 
190 static int
191 ssh2_capable(int remote_major, int remote_minor)
192 {
193 	switch (remote_major) {
194 	case 1:
195 		if (remote_minor == 99)
196 			return 1;
197 		break;
198 	case 2:
199 		return 1;
200 	default:
201 		break;
202 	}
203 	return 0;
204 }
205 
206 static void
207 keygrab_ssh2(con *c)
208 {
209 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
210 	int r;
211 
212 	switch (c->c_keytype) {
213 	case KT_DSA:
214 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
215 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
216 		break;
217 	case KT_RSA:
218 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
219 		    "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
220 		break;
221 	case KT_ED25519:
222 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
223 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
224 		break;
225 	case KT_ECDSA:
226 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
227 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
228 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
229 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
230 		    "ecdsa-sha2-nistp256,"
231 		    "ecdsa-sha2-nistp384,"
232 		    "ecdsa-sha2-nistp521";
233 		break;
234 	default:
235 		fatal("unknown key type %d", c->c_keytype);
236 		break;
237 	}
238 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
239 		free(c->c_ssh);
240 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
241 		exit(1);
242 	}
243 #ifdef WITH_OPENSSL
244 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
245 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
246 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
247 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
248 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
249 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
250 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
251 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
252 #endif
253 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
254 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
255 	/*
256 	 * do the key-exchange until an error occurs or until
257 	 * the key_print_wrapper() callback sets c_done.
258 	 */
259 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
260 }
261 
262 static void
263 keyprint_one(const char *host, struct sshkey *key)
264 {
265 	char *hostport;
266 	const char *known_host, *hashed;
267 
268 	hostport = put_host_port(host, ssh_port);
269 	lowercase(hostport);
270 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
271 		fatal("host_hash failed");
272 	known_host = hash_hosts ? hashed : hostport;
273 	if (!get_cert)
274 		fprintf(stdout, "%s ", known_host);
275 	sshkey_write(key, stdout);
276 	fputs("\n", stdout);
277 	free(hostport);
278 }
279 
280 static void
281 keyprint(con *c, struct sshkey *key)
282 {
283 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
284 	char *host, *ohosts;
285 
286 	if (key == NULL)
287 		return;
288 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
289 		keyprint_one(hosts, key);
290 		return;
291 	}
292 	ohosts = hosts = xstrdup(hosts);
293 	while ((host = strsep(&hosts, ",")) != NULL)
294 		keyprint_one(host, key);
295 	free(ohosts);
296 }
297 
298 static int
299 tcpconnect(char *host)
300 {
301 	struct addrinfo hints, *ai, *aitop;
302 	char strport[NI_MAXSERV];
303 	int gaierr, s = -1;
304 
305 	snprintf(strport, sizeof strport, "%d", ssh_port);
306 	memset(&hints, 0, sizeof(hints));
307 	hints.ai_family = IPv4or6;
308 	hints.ai_socktype = SOCK_STREAM;
309 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
310 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
311 		return -1;
312 	}
313 	for (ai = aitop; ai; ai = ai->ai_next) {
314 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
315 		if (s < 0) {
316 			error("socket: %s", strerror(errno));
317 			continue;
318 		}
319 		if (set_nonblock(s) == -1)
320 			fatal("%s: set_nonblock(%d)", __func__, s);
321 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
322 		    errno != EINPROGRESS)
323 			error("connect (`%s'): %s", host, strerror(errno));
324 		else
325 			break;
326 		close(s);
327 		s = -1;
328 	}
329 	freeaddrinfo(aitop);
330 	return s;
331 }
332 
333 static int
334 conalloc(char *iname, char *oname, int keytype)
335 {
336 	char *namebase, *name, *namelist;
337 	int s;
338 
339 	namebase = namelist = xstrdup(iname);
340 
341 	do {
342 		name = xstrsep(&namelist, ",");
343 		if (!name) {
344 			free(namebase);
345 			return (-1);
346 		}
347 	} while ((s = tcpconnect(name)) < 0);
348 
349 	if (s >= maxfd)
350 		fatal("conalloc: fdno %d too high", s);
351 	if (fdcon[s].c_status)
352 		fatal("conalloc: attempt to reuse fdno %d", s);
353 
354 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
355 	fdcon[s].c_fd = s;
356 	fdcon[s].c_status = CS_CON;
357 	fdcon[s].c_namebase = namebase;
358 	fdcon[s].c_name = name;
359 	fdcon[s].c_namelist = namelist;
360 	fdcon[s].c_output_name = xstrdup(oname);
361 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
362 	fdcon[s].c_len = 4;
363 	fdcon[s].c_off = 0;
364 	fdcon[s].c_keytype = keytype;
365 	gettimeofday(&fdcon[s].c_tv, NULL);
366 	fdcon[s].c_tv.tv_sec += timeout;
367 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
368 	FD_SET(s, read_wait);
369 	ncon++;
370 	return (s);
371 }
372 
373 static void
374 confree(int s)
375 {
376 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
377 		fatal("confree: attempt to free bad fdno %d", s);
378 	free(fdcon[s].c_namebase);
379 	free(fdcon[s].c_output_name);
380 	if (fdcon[s].c_status == CS_KEYS)
381 		free(fdcon[s].c_data);
382 	fdcon[s].c_status = CS_UNUSED;
383 	fdcon[s].c_keytype = 0;
384 	if (fdcon[s].c_ssh) {
385 		ssh_packet_close(fdcon[s].c_ssh);
386 		free(fdcon[s].c_ssh);
387 		fdcon[s].c_ssh = NULL;
388 	} else
389 		close(s);
390 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
391 	FD_CLR(s, read_wait);
392 	ncon--;
393 }
394 
395 static void
396 contouch(int s)
397 {
398 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
399 	gettimeofday(&fdcon[s].c_tv, NULL);
400 	fdcon[s].c_tv.tv_sec += timeout;
401 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
402 }
403 
404 static int
405 conrecycle(int s)
406 {
407 	con *c = &fdcon[s];
408 	int ret;
409 
410 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
411 	confree(s);
412 	return (ret);
413 }
414 
415 static void
416 congreet(int s)
417 {
418 	int n = 0, remote_major = 0, remote_minor = 0;
419 	char buf[256], *cp;
420 	char remote_version[sizeof buf];
421 	size_t bufsiz;
422 	con *c = &fdcon[s];
423 
424 	/* send client banner */
425 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
426 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
427 	if (n < 0 || (size_t)n >= sizeof(buf)) {
428 		error("snprintf: buffer too small");
429 		confree(s);
430 		return;
431 	}
432 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
433 		error("write (%s): %s", c->c_name, strerror(errno));
434 		confree(s);
435 		return;
436 	}
437 
438 	for (;;) {
439 		memset(buf, '\0', sizeof(buf));
440 		bufsiz = sizeof(buf);
441 		cp = buf;
442 		while (bufsiz-- &&
443 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
444 			if (*cp == '\r')
445 				*cp = '\n';
446 			cp++;
447 		}
448 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
449 			break;
450 	}
451 	if (n == 0) {
452 		switch (errno) {
453 		case EPIPE:
454 			error("%s: Connection closed by remote host", c->c_name);
455 			break;
456 		case ECONNREFUSED:
457 			break;
458 		default:
459 			error("read (%s): %s", c->c_name, strerror(errno));
460 			break;
461 		}
462 		conrecycle(s);
463 		return;
464 	}
465 	if (*cp != '\n' && *cp != '\r') {
466 		error("%s: bad greeting", c->c_name);
467 		confree(s);
468 		return;
469 	}
470 	*cp = '\0';
471 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
472 		fatal("ssh_packet_set_connection failed");
473 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
474 	ssh_set_app_data(c->c_ssh, c);	/* back link */
475 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
476 	    &remote_major, &remote_minor, remote_version) == 3)
477 		c->c_ssh->compat = compat_datafellows(remote_version);
478 	else
479 		c->c_ssh->compat = 0;
480 	if (!ssh2_capable(remote_major, remote_minor)) {
481 		debug("%s doesn't support ssh2", c->c_name);
482 		confree(s);
483 		return;
484 	}
485 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
486 	keygrab_ssh2(c);
487 	confree(s);
488 }
489 
490 static void
491 conread(int s)
492 {
493 	con *c = &fdcon[s];
494 	size_t n;
495 
496 	if (c->c_status == CS_CON) {
497 		congreet(s);
498 		return;
499 	}
500 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
501 	if (n == 0) {
502 		error("read (%s): %s", c->c_name, strerror(errno));
503 		confree(s);
504 		return;
505 	}
506 	c->c_off += n;
507 
508 	if (c->c_off == c->c_len)
509 		switch (c->c_status) {
510 		case CS_SIZE:
511 			c->c_plen = htonl(c->c_plen);
512 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
513 			c->c_off = 0;
514 			c->c_data = xmalloc(c->c_len);
515 			c->c_status = CS_KEYS;
516 			break;
517 		default:
518 			fatal("conread: invalid status %d", c->c_status);
519 			break;
520 		}
521 
522 	contouch(s);
523 }
524 
525 static void
526 conloop(void)
527 {
528 	struct timeval seltime, now;
529 	fd_set *r, *e;
530 	con *c;
531 	int i;
532 
533 	gettimeofday(&now, NULL);
534 	c = TAILQ_FIRST(&tq);
535 
536 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
537 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
538 		seltime = c->c_tv;
539 		seltime.tv_sec -= now.tv_sec;
540 		seltime.tv_usec -= now.tv_usec;
541 		if (seltime.tv_usec < 0) {
542 			seltime.tv_usec += 1000000;
543 			seltime.tv_sec--;
544 		}
545 	} else
546 		timerclear(&seltime);
547 
548 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
549 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
550 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
551 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
552 
553 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
554 	    (errno == EAGAIN || errno == EINTR))
555 		;
556 
557 	for (i = 0; i < maxfd; i++) {
558 		if (FD_ISSET(i, e)) {
559 			error("%s: exception!", fdcon[i].c_name);
560 			confree(i);
561 		} else if (FD_ISSET(i, r))
562 			conread(i);
563 	}
564 	free(r);
565 	free(e);
566 
567 	c = TAILQ_FIRST(&tq);
568 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
569 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
570 		int s = c->c_fd;
571 
572 		c = TAILQ_NEXT(c, c_link);
573 		conrecycle(s);
574 	}
575 }
576 
577 static void
578 do_host(char *host)
579 {
580 	char *name = strnnsep(&host, " \t\n");
581 	int j;
582 
583 	if (name == NULL)
584 		return;
585 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
586 		if (get_keytypes & j) {
587 			while (ncon >= MAXCON)
588 				conloop();
589 			conalloc(name, *host ? host : name, j);
590 		}
591 	}
592 }
593 
594 __dead void
595 fatal(const char *fmt,...)
596 {
597 	va_list args;
598 
599 	va_start(args, fmt);
600 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
601 	va_end(args);
602 	exit(255);
603 }
604 
605 __dead static void
606 usage(void)
607 {
608 	fprintf(stderr,
609 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
610 	    "\t\t   [host | addrlist namelist] ...\n",
611 	    __progname);
612 	exit(1);
613 }
614 
615 int
616 main(int argc, char **argv)
617 {
618 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
619 	int opt, fopt_count = 0, j;
620 	char *tname, *cp, line[NI_MAXHOST];
621 	FILE *fp;
622 	u_long linenum;
623 
624 	extern int optind;
625 	extern char *optarg;
626 
627 	ssh_malloc_init();	/* must be called before any mallocs */
628 	TAILQ_INIT(&tq);
629 
630 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
631 	sanitise_stdfd();
632 
633 	if (argc <= 1)
634 		usage();
635 
636 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
637 		switch (opt) {
638 		case 'H':
639 			hash_hosts = 1;
640 			break;
641 		case 'c':
642 			get_cert = 1;
643 			break;
644 		case 'p':
645 			ssh_port = a2port(optarg);
646 			if (ssh_port <= 0) {
647 				fprintf(stderr, "Bad port '%s'\n", optarg);
648 				exit(1);
649 			}
650 			break;
651 		case 'T':
652 			timeout = convtime(optarg);
653 			if (timeout == -1 || timeout == 0) {
654 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
655 				usage();
656 			}
657 			break;
658 		case 'v':
659 			if (!debug_flag) {
660 				debug_flag = 1;
661 				log_level = SYSLOG_LEVEL_DEBUG1;
662 			}
663 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
664 				log_level++;
665 			else
666 				fatal("Too high debugging level.");
667 			break;
668 		case 'f':
669 			if (strcmp(optarg, "-") == 0)
670 				optarg = NULL;
671 			argv[fopt_count++] = optarg;
672 			break;
673 		case 't':
674 			get_keytypes = 0;
675 			tname = strtok(optarg, ",");
676 			while (tname) {
677 				int type = sshkey_type_from_name(tname);
678 
679 				switch (type) {
680 				case KEY_DSA:
681 					get_keytypes |= KT_DSA;
682 					break;
683 				case KEY_ECDSA:
684 					get_keytypes |= KT_ECDSA;
685 					break;
686 				case KEY_RSA:
687 					get_keytypes |= KT_RSA;
688 					break;
689 				case KEY_ED25519:
690 					get_keytypes |= KT_ED25519;
691 					break;
692 				case KEY_UNSPEC:
693 				default:
694 					fatal("Unknown key type \"%s\"", tname);
695 				}
696 				tname = strtok(NULL, ",");
697 			}
698 			break;
699 		case '4':
700 			IPv4or6 = AF_INET;
701 			break;
702 		case '6':
703 			IPv4or6 = AF_INET6;
704 			break;
705 		case '?':
706 		default:
707 			usage();
708 		}
709 	}
710 	if (optind == argc && !fopt_count)
711 		usage();
712 
713 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
714 
715 	maxfd = fdlim_get(1);
716 	if (maxfd < 0)
717 		fatal("%s: fdlim_get: bad value", __progname);
718 	if (maxfd > MAXMAXFD)
719 		maxfd = MAXMAXFD;
720 	if (MAXCON <= 0)
721 		fatal("%s: not enough file descriptors", __progname);
722 	if (maxfd > fdlim_get(0))
723 		fdlim_set(maxfd);
724 	fdcon = xcalloc(maxfd, sizeof(con));
725 
726 	read_wait_nfdset = howmany(maxfd, NFDBITS);
727 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
728 
729 	for (j = 0; j < fopt_count; j++) {
730 		if (argv[j] == NULL)
731 			fp = stdin;
732 		else if ((fp = fopen(argv[j], "r")) == NULL)
733 			fatal("%s: %s: %s", __progname, argv[j],
734 			    strerror(errno));
735 		linenum = 0;
736 
737 		while (read_keyfile_line(fp,
738 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
739 		    &linenum) != -1) {
740 			/* Chomp off trailing whitespace and comments */
741 			if ((cp = strchr(line, '#')) == NULL)
742 				cp = line + strlen(line) - 1;
743 			while (cp >= line) {
744 				if (*cp == ' ' || *cp == '\t' ||
745 				    *cp == '\n' || *cp == '#')
746 					*cp-- = '\0';
747 				else
748 					break;
749 			}
750 
751 			/* Skip empty lines */
752 			if (*line == '\0')
753 				continue;
754 
755 			do_host(line);
756 		}
757 
758 		if (ferror(fp))
759 			fatal("%s: %s: %s", __progname, argv[j],
760 			    strerror(errno));
761 
762 		fclose(fp);
763 	}
764 
765 	while (optind < argc)
766 		do_host(argv[optind++]);
767 
768 	while (ncon > 0)
769 		conloop();
770 
771 	return (0);
772 }
773