xref: /openbsd-src/usr.bin/ssh/ssh-keyscan.c (revision 0b7734b3d77bb9b21afec6f4621cae6c805dbd45)
1 /* $OpenBSD: ssh-keyscan.c,v 1.106 2016/05/02 10:26:04 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_cert = 0;
58 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
59 
60 int hash_hosts = 0;		/* Hash hostname on output */
61 
62 #define MAXMAXFD 256
63 
64 /* The number of seconds after which to give up on a TCP connection */
65 int timeout = 5;
66 
67 int maxfd;
68 #define MAXCON (maxfd - 10)
69 
70 extern char *__progname;
71 fd_set *read_wait;
72 size_t read_wait_nfdset;
73 int ncon;
74 
75 /*
76  * Keep a connection structure for each file descriptor.  The state
77  * associated with file descriptor n is held in fdcon[n].
78  */
79 typedef struct Connection {
80 	u_char c_status;	/* State of connection on this file desc. */
81 #define CS_UNUSED 0		/* File descriptor unused */
82 #define CS_CON 1		/* Waiting to connect/read greeting */
83 #define CS_SIZE 2		/* Waiting to read initial packet size */
84 #define CS_KEYS 3		/* Waiting to read public key packet */
85 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
86 	int c_plen;		/* Packet length field for ssh packet */
87 	int c_len;		/* Total bytes which must be read. */
88 	int c_off;		/* Length of data read so far. */
89 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
90 	sig_atomic_t c_done;	/* SSH2 done */
91 	char *c_namebase;	/* Address to free for c_name and c_namelist */
92 	char *c_name;		/* Hostname of connection for errors */
93 	char *c_namelist;	/* Pointer to other possible addresses */
94 	char *c_output_name;	/* Hostname of connection for output */
95 	char *c_data;		/* Data read from this fd */
96 	struct ssh *c_ssh;	/* SSH-connection */
97 	struct timeval c_tv;	/* Time at which connection gets aborted */
98 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
99 } con;
100 
101 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
102 con *fdcon;
103 
104 static void keyprint(con *c, struct sshkey *key);
105 
106 static int
107 fdlim_get(int hard)
108 {
109 	struct rlimit rlfd;
110 
111 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
112 		return (-1);
113 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
114 		return sysconf(_SC_OPEN_MAX);
115 	else
116 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
117 }
118 
119 static int
120 fdlim_set(int lim)
121 {
122 	struct rlimit rlfd;
123 
124 	if (lim <= 0)
125 		return (-1);
126 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
127 		return (-1);
128 	rlfd.rlim_cur = lim;
129 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
130 		return (-1);
131 	return (0);
132 }
133 
134 /*
135  * This is an strsep function that returns a null field for adjacent
136  * separators.  This is the same as the 4.4BSD strsep, but different from the
137  * one in the GNU libc.
138  */
139 static char *
140 xstrsep(char **str, const char *delim)
141 {
142 	char *s, *e;
143 
144 	if (!**str)
145 		return (NULL);
146 
147 	s = *str;
148 	e = s + strcspn(s, delim);
149 
150 	if (*e != '\0')
151 		*e++ = '\0';
152 	*str = e;
153 
154 	return (s);
155 }
156 
157 /*
158  * Get the next non-null token (like GNU strsep).  Strsep() will return a
159  * null token for two adjacent separators, so we may have to loop.
160  */
161 static char *
162 strnnsep(char **stringp, char *delim)
163 {
164 	char *tok;
165 
166 	do {
167 		tok = xstrsep(stringp, delim);
168 	} while (tok && *tok == '\0');
169 	return (tok);
170 }
171 
172 #ifdef WITH_SSH1
173 static struct sshkey *
174 keygrab_ssh1(con *c)
175 {
176 	static struct sshkey *rsa;
177 	static struct sshbuf *msg;
178 	int r;
179 	u_char type;
180 
181 	if (rsa == NULL) {
182 		if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
183 			error("%s: sshkey_new failed", __func__);
184 			return NULL;
185 		}
186 		if ((msg = sshbuf_new()) == NULL)
187 			fatal("%s: sshbuf_new failed", __func__);
188 	}
189 	if ((r = sshbuf_put(msg, c->c_data, c->c_plen)) != 0 ||
190 	    (r = sshbuf_consume(msg, 8 - (c->c_plen & 7))) != 0 || /* padding */
191 	    (r = sshbuf_get_u8(msg, &type)) != 0)
192 		goto buf_err;
193 	if (type != (int) SSH_SMSG_PUBLIC_KEY) {
194 		error("%s: invalid packet type", c->c_name);
195 		sshbuf_reset(msg);
196 		return NULL;
197 	}
198 	if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
199 	    /* server key */
200 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
201 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
202 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
203 	    /* host key */
204 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
205 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->e)) != 0 ||
206 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->n)) != 0) {
207  buf_err:
208 		error("%s: buffer error: %s", __func__, ssh_err(r));
209 		sshbuf_reset(msg);
210 		return NULL;
211 	}
212 
213 	sshbuf_reset(msg);
214 
215 	return (rsa);
216 }
217 #endif
218 
219 static int
220 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
221 {
222 	con *c;
223 
224 	if ((c = ssh_get_app_data(ssh)) != NULL)
225 		keyprint(c, hostkey);
226 	/* always abort key exchange */
227 	return -1;
228 }
229 
230 static int
231 ssh2_capable(int remote_major, int remote_minor)
232 {
233 	switch (remote_major) {
234 	case 1:
235 		if (remote_minor == 99)
236 			return 1;
237 		break;
238 	case 2:
239 		return 1;
240 	default:
241 		break;
242 	}
243 	return 0;
244 }
245 
246 static void
247 keygrab_ssh2(con *c)
248 {
249 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
250 	int r;
251 
252 	enable_compat20();
253 	switch (c->c_keytype) {
254 	case KT_DSA:
255 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
256 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
257 		break;
258 	case KT_RSA:
259 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
260 		    "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
261 		break;
262 	case KT_ED25519:
263 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
264 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
265 		break;
266 	case KT_ECDSA:
267 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
268 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
269 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
270 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
271 		    "ecdsa-sha2-nistp256,"
272 		    "ecdsa-sha2-nistp384,"
273 		    "ecdsa-sha2-nistp521";
274 		break;
275 	default:
276 		fatal("unknown key type %d", c->c_keytype);
277 		break;
278 	}
279 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
280 		free(c->c_ssh);
281 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
282 		exit(1);
283 	}
284 #ifdef WITH_OPENSSL
285 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
286 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
287 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
288 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
289 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
290 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
291 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
292 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
293 #endif
294 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
295 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
296 	/*
297 	 * do the key-exchange until an error occurs or until
298 	 * the key_print_wrapper() callback sets c_done.
299 	 */
300 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
301 }
302 
303 static void
304 keyprint_one(char *host, struct sshkey *key)
305 {
306 	char *hostport;
307 
308 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
309 		fatal("host_hash failed");
310 
311 	hostport = put_host_port(host, ssh_port);
312 	if (!get_cert)
313 		fprintf(stdout, "%s ", hostport);
314 	sshkey_write(key, stdout);
315 	fputs("\n", stdout);
316 	free(hostport);
317 }
318 
319 static void
320 keyprint(con *c, struct sshkey *key)
321 {
322 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
323 	char *host, *ohosts;
324 
325 	if (key == NULL)
326 		return;
327 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
328 		keyprint_one(hosts, key);
329 		return;
330 	}
331 	ohosts = hosts = xstrdup(hosts);
332 	while ((host = strsep(&hosts, ",")) != NULL)
333 		keyprint_one(host, key);
334 	free(ohosts);
335 }
336 
337 static int
338 tcpconnect(char *host)
339 {
340 	struct addrinfo hints, *ai, *aitop;
341 	char strport[NI_MAXSERV];
342 	int gaierr, s = -1;
343 
344 	snprintf(strport, sizeof strport, "%d", ssh_port);
345 	memset(&hints, 0, sizeof(hints));
346 	hints.ai_family = IPv4or6;
347 	hints.ai_socktype = SOCK_STREAM;
348 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
349 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
350 		return -1;
351 	}
352 	for (ai = aitop; ai; ai = ai->ai_next) {
353 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
354 		if (s < 0) {
355 			error("socket: %s", strerror(errno));
356 			continue;
357 		}
358 		if (set_nonblock(s) == -1)
359 			fatal("%s: set_nonblock(%d)", __func__, s);
360 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
361 		    errno != EINPROGRESS)
362 			error("connect (`%s'): %s", host, strerror(errno));
363 		else
364 			break;
365 		close(s);
366 		s = -1;
367 	}
368 	freeaddrinfo(aitop);
369 	return s;
370 }
371 
372 static int
373 conalloc(char *iname, char *oname, int keytype)
374 {
375 	char *namebase, *name, *namelist;
376 	int s;
377 
378 	namebase = namelist = xstrdup(iname);
379 
380 	do {
381 		name = xstrsep(&namelist, ",");
382 		if (!name) {
383 			free(namebase);
384 			return (-1);
385 		}
386 	} while ((s = tcpconnect(name)) < 0);
387 
388 	if (s >= maxfd)
389 		fatal("conalloc: fdno %d too high", s);
390 	if (fdcon[s].c_status)
391 		fatal("conalloc: attempt to reuse fdno %d", s);
392 
393 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
394 	fdcon[s].c_fd = s;
395 	fdcon[s].c_status = CS_CON;
396 	fdcon[s].c_namebase = namebase;
397 	fdcon[s].c_name = name;
398 	fdcon[s].c_namelist = namelist;
399 	fdcon[s].c_output_name = xstrdup(oname);
400 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
401 	fdcon[s].c_len = 4;
402 	fdcon[s].c_off = 0;
403 	fdcon[s].c_keytype = keytype;
404 	gettimeofday(&fdcon[s].c_tv, NULL);
405 	fdcon[s].c_tv.tv_sec += timeout;
406 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
407 	FD_SET(s, read_wait);
408 	ncon++;
409 	return (s);
410 }
411 
412 static void
413 confree(int s)
414 {
415 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
416 		fatal("confree: attempt to free bad fdno %d", s);
417 	close(s);
418 	free(fdcon[s].c_namebase);
419 	free(fdcon[s].c_output_name);
420 	if (fdcon[s].c_status == CS_KEYS)
421 		free(fdcon[s].c_data);
422 	fdcon[s].c_status = CS_UNUSED;
423 	fdcon[s].c_keytype = 0;
424 	if (fdcon[s].c_ssh) {
425 		ssh_packet_close(fdcon[s].c_ssh);
426 		free(fdcon[s].c_ssh);
427 		fdcon[s].c_ssh = NULL;
428 	}
429 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
430 	FD_CLR(s, read_wait);
431 	ncon--;
432 }
433 
434 static void
435 contouch(int s)
436 {
437 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
438 	gettimeofday(&fdcon[s].c_tv, NULL);
439 	fdcon[s].c_tv.tv_sec += timeout;
440 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
441 }
442 
443 static int
444 conrecycle(int s)
445 {
446 	con *c = &fdcon[s];
447 	int ret;
448 
449 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
450 	confree(s);
451 	return (ret);
452 }
453 
454 static void
455 congreet(int s)
456 {
457 	int n = 0, remote_major = 0, remote_minor = 0;
458 	char buf[256], *cp;
459 	char remote_version[sizeof buf];
460 	size_t bufsiz;
461 	con *c = &fdcon[s];
462 
463 	for (;;) {
464 		memset(buf, '\0', sizeof(buf));
465 		bufsiz = sizeof(buf);
466 		cp = buf;
467 		while (bufsiz-- &&
468 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
469 			if (*cp == '\r')
470 				*cp = '\n';
471 			cp++;
472 		}
473 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
474 			break;
475 	}
476 	if (n == 0) {
477 		switch (errno) {
478 		case EPIPE:
479 			error("%s: Connection closed by remote host", c->c_name);
480 			break;
481 		case ECONNREFUSED:
482 			break;
483 		default:
484 			error("read (%s): %s", c->c_name, strerror(errno));
485 			break;
486 		}
487 		conrecycle(s);
488 		return;
489 	}
490 	if (*cp != '\n' && *cp != '\r') {
491 		error("%s: bad greeting", c->c_name);
492 		confree(s);
493 		return;
494 	}
495 	*cp = '\0';
496 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
497 		fatal("ssh_packet_set_connection failed");
498 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
499 	ssh_set_app_data(c->c_ssh, c);	/* back link */
500 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
501 	    &remote_major, &remote_minor, remote_version) == 3)
502 		c->c_ssh->compat = compat_datafellows(remote_version);
503 	else
504 		c->c_ssh->compat = 0;
505 	if (c->c_keytype != KT_RSA1) {
506 		if (!ssh2_capable(remote_major, remote_minor)) {
507 			debug("%s doesn't support ssh2", c->c_name);
508 			confree(s);
509 			return;
510 		}
511 	} else if (remote_major != 1) {
512 		debug("%s doesn't support ssh1", c->c_name);
513 		confree(s);
514 		return;
515 	}
516 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
517 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
518 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
519 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
520 	if (n < 0 || (size_t)n >= sizeof(buf)) {
521 		error("snprintf: buffer too small");
522 		confree(s);
523 		return;
524 	}
525 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
526 		error("write (%s): %s", c->c_name, strerror(errno));
527 		confree(s);
528 		return;
529 	}
530 	if (c->c_keytype != KT_RSA1) {
531 		keygrab_ssh2(c);
532 		confree(s);
533 		return;
534 	}
535 	c->c_status = CS_SIZE;
536 	contouch(s);
537 }
538 
539 static void
540 conread(int s)
541 {
542 	con *c = &fdcon[s];
543 	size_t n;
544 
545 	if (c->c_status == CS_CON) {
546 		congreet(s);
547 		return;
548 	}
549 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
550 	if (n == 0) {
551 		error("read (%s): %s", c->c_name, strerror(errno));
552 		confree(s);
553 		return;
554 	}
555 	c->c_off += n;
556 
557 	if (c->c_off == c->c_len)
558 		switch (c->c_status) {
559 		case CS_SIZE:
560 			c->c_plen = htonl(c->c_plen);
561 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
562 			c->c_off = 0;
563 			c->c_data = xmalloc(c->c_len);
564 			c->c_status = CS_KEYS;
565 			break;
566 #ifdef WITH_SSH1
567 		case CS_KEYS:
568 			keyprint(c, keygrab_ssh1(c));
569 			confree(s);
570 			return;
571 #endif
572 		default:
573 			fatal("conread: invalid status %d", c->c_status);
574 			break;
575 		}
576 
577 	contouch(s);
578 }
579 
580 static void
581 conloop(void)
582 {
583 	struct timeval seltime, now;
584 	fd_set *r, *e;
585 	con *c;
586 	int i;
587 
588 	gettimeofday(&now, NULL);
589 	c = TAILQ_FIRST(&tq);
590 
591 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
592 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
593 		seltime = c->c_tv;
594 		seltime.tv_sec -= now.tv_sec;
595 		seltime.tv_usec -= now.tv_usec;
596 		if (seltime.tv_usec < 0) {
597 			seltime.tv_usec += 1000000;
598 			seltime.tv_sec--;
599 		}
600 	} else
601 		timerclear(&seltime);
602 
603 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
604 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
605 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
606 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
607 
608 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
609 	    (errno == EAGAIN || errno == EINTR))
610 		;
611 
612 	for (i = 0; i < maxfd; i++) {
613 		if (FD_ISSET(i, e)) {
614 			error("%s: exception!", fdcon[i].c_name);
615 			confree(i);
616 		} else if (FD_ISSET(i, r))
617 			conread(i);
618 	}
619 	free(r);
620 	free(e);
621 
622 	c = TAILQ_FIRST(&tq);
623 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
624 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
625 		int s = c->c_fd;
626 
627 		c = TAILQ_NEXT(c, c_link);
628 		conrecycle(s);
629 	}
630 }
631 
632 static void
633 do_host(char *host)
634 {
635 	char *name = strnnsep(&host, " \t\n");
636 	int j;
637 
638 	if (name == NULL)
639 		return;
640 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
641 		if (get_keytypes & j) {
642 			while (ncon >= MAXCON)
643 				conloop();
644 			conalloc(name, *host ? host : name, j);
645 		}
646 	}
647 }
648 
649 void
650 fatal(const char *fmt,...)
651 {
652 	va_list args;
653 
654 	va_start(args, fmt);
655 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
656 	va_end(args);
657 	exit(255);
658 }
659 
660 static void
661 usage(void)
662 {
663 	fprintf(stderr,
664 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
665 	    "\t\t   [host | addrlist namelist] ...\n",
666 	    __progname);
667 	exit(1);
668 }
669 
670 int
671 main(int argc, char **argv)
672 {
673 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
674 	int opt, fopt_count = 0, j;
675 	char *tname, *cp, line[NI_MAXHOST];
676 	FILE *fp;
677 	u_long linenum;
678 
679 	extern int optind;
680 	extern char *optarg;
681 
682 	ssh_malloc_init();	/* must be called before any mallocs */
683 	TAILQ_INIT(&tq);
684 
685 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
686 	sanitise_stdfd();
687 
688 	if (argc <= 1)
689 		usage();
690 
691 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
692 		switch (opt) {
693 		case 'H':
694 			hash_hosts = 1;
695 			break;
696 		case 'c':
697 			get_cert = 1;
698 			break;
699 		case 'p':
700 			ssh_port = a2port(optarg);
701 			if (ssh_port <= 0) {
702 				fprintf(stderr, "Bad port '%s'\n", optarg);
703 				exit(1);
704 			}
705 			break;
706 		case 'T':
707 			timeout = convtime(optarg);
708 			if (timeout == -1 || timeout == 0) {
709 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
710 				usage();
711 			}
712 			break;
713 		case 'v':
714 			if (!debug_flag) {
715 				debug_flag = 1;
716 				log_level = SYSLOG_LEVEL_DEBUG1;
717 			}
718 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
719 				log_level++;
720 			else
721 				fatal("Too high debugging level.");
722 			break;
723 		case 'f':
724 			if (strcmp(optarg, "-") == 0)
725 				optarg = NULL;
726 			argv[fopt_count++] = optarg;
727 			break;
728 		case 't':
729 			get_keytypes = 0;
730 			tname = strtok(optarg, ",");
731 			while (tname) {
732 				int type = sshkey_type_from_name(tname);
733 				switch (type) {
734 				case KEY_RSA1:
735 					get_keytypes |= KT_RSA1;
736 					break;
737 				case KEY_DSA:
738 					get_keytypes |= KT_DSA;
739 					break;
740 				case KEY_ECDSA:
741 					get_keytypes |= KT_ECDSA;
742 					break;
743 				case KEY_RSA:
744 					get_keytypes |= KT_RSA;
745 					break;
746 				case KEY_ED25519:
747 					get_keytypes |= KT_ED25519;
748 					break;
749 				case KEY_UNSPEC:
750 					fatal("unknown key type %s", tname);
751 				}
752 				tname = strtok(NULL, ",");
753 			}
754 			break;
755 		case '4':
756 			IPv4or6 = AF_INET;
757 			break;
758 		case '6':
759 			IPv4or6 = AF_INET6;
760 			break;
761 		case '?':
762 		default:
763 			usage();
764 		}
765 	}
766 	if (optind == argc && !fopt_count)
767 		usage();
768 
769 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
770 
771 	maxfd = fdlim_get(1);
772 	if (maxfd < 0)
773 		fatal("%s: fdlim_get: bad value", __progname);
774 	if (maxfd > MAXMAXFD)
775 		maxfd = MAXMAXFD;
776 	if (MAXCON <= 0)
777 		fatal("%s: not enough file descriptors", __progname);
778 	if (maxfd > fdlim_get(0))
779 		fdlim_set(maxfd);
780 	fdcon = xcalloc(maxfd, sizeof(con));
781 
782 	read_wait_nfdset = howmany(maxfd, NFDBITS);
783 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
784 
785 	for (j = 0; j < fopt_count; j++) {
786 		if (argv[j] == NULL)
787 			fp = stdin;
788 		else if ((fp = fopen(argv[j], "r")) == NULL)
789 			fatal("%s: %s: %s", __progname, argv[j],
790 			    strerror(errno));
791 		linenum = 0;
792 
793 		while (read_keyfile_line(fp,
794 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
795 		    &linenum) != -1) {
796 			/* Chomp off trailing whitespace and comments */
797 			if ((cp = strchr(line, '#')) == NULL)
798 				cp = line + strlen(line) - 1;
799 			while (cp >= line) {
800 				if (*cp == ' ' || *cp == '\t' ||
801 				    *cp == '\n' || *cp == '#')
802 					*cp-- = '\0';
803 				else
804 					break;
805 			}
806 
807 			/* Skip empty lines */
808 			if (*line == '\0')
809 				continue;
810 
811 			do_host(line);
812 		}
813 
814 		if (ferror(fp))
815 			fatal("%s: %s: %s", __progname, argv[j],
816 			    strerror(errno));
817 
818 		fclose(fp);
819 	}
820 
821 	while (optind < argc)
822 		do_host(argv[optind++]);
823 
824 	while (ncon > 0)
825 		conloop();
826 
827 	return (0);
828 }
829