xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision fdd524d4ccd2bb0c6f67401e938dabf773eb0372)
1 /*	$NetBSD: ssh-keyscan.c,v 1.16 2016/03/16 20:57:46 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.105 2016/02/15 09:47:49 dtucker Exp $ */
3 
4 /*
5  * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
6  *
7  * Modification and redistribution in source and binary forms is
8  * permitted provided that due credit is given to the author and the
9  * OpenBSD project by leaving this copyright notice intact.
10  */
11 
12 #include "includes.h"
13 __RCSID("$NetBSD: ssh-keyscan.c,v 1.16 2016/03/16 20:57:46 christos Exp $");
14 
15 #include <sys/param.h>
16 #include <sys/types.h>
17 #include <sys/socket.h>
18 #include <sys/queue.h>
19 #include <sys/time.h>
20 #include <sys/resource.h>
21 
22 #include <openssl/bn.h>
23 
24 #include <errno.h>
25 #include <netdb.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_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_RSA1, KT_DSA, or KT_RSA */
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 #ifdef WITH_SSH1
179 static struct sshkey *
180 keygrab_ssh1(con *c)
181 {
182 	static struct sshkey *rsa;
183 	static struct sshbuf *msg;
184 	int r;
185 	u_char type;
186 
187 	if (rsa == NULL) {
188 		if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
189 			error("%s: sshkey_new failed", __func__);
190 			return NULL;
191 		}
192 		if ((msg = sshbuf_new()) == NULL)
193 			fatal("%s: sshbuf_new failed", __func__);
194 	}
195 	if ((r = sshbuf_put(msg, c->c_data, c->c_plen)) != 0 ||
196 	    (r = sshbuf_consume(msg, 8 - (c->c_plen & 7))) != 0 || /* padding */
197 	    (r = sshbuf_get_u8(msg, &type)) != 0)
198 		goto buf_err;
199 	if (type != (int) SSH_SMSG_PUBLIC_KEY) {
200 		error("%s: invalid packet type", c->c_name);
201 		sshbuf_reset(msg);
202 		return NULL;
203 	}
204 	if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
205 	    /* server key */
206 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
207 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
208 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
209 	    /* host key */
210 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
211 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->e)) != 0 ||
212 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->n)) != 0) {
213  buf_err:
214 		error("%s: buffer error: %s", __func__, ssh_err(r));
215 		sshbuf_reset(msg);
216 		return NULL;
217 	}
218 
219 	sshbuf_reset(msg);
220 
221 	return (rsa);
222 }
223 #endif
224 
225 static int
226 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
227 {
228 	con *c;
229 
230 	if ((c = ssh_get_app_data(ssh)) != NULL)
231 		keyprint(c, hostkey);
232 	/* always abort key exchange */
233 	return -1;
234 }
235 
236 static int
237 ssh2_capable(int remote_major, int remote_minor)
238 {
239 	switch (remote_major) {
240 	case 1:
241 		if (remote_minor == 99)
242 			return 1;
243 		break;
244 	case 2:
245 		return 1;
246 	default:
247 		break;
248 	}
249 	return 0;
250 }
251 
252 static void
253 keygrab_ssh2(con *c)
254 {
255 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
256 	int r;
257 
258 	enable_compat20();
259 	switch (c->c_keytype) {
260 	case KT_DSA:
261 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
262 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
263 		break;
264 	case KT_RSA:
265 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
266 		    "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
267 		break;
268 	case KT_ED25519:
269 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
270 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
271 		break;
272 	case KT_ECDSA:
273 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
274 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
275 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
276 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
277 		    "ecdsa-sha2-nistp256,"
278 		    "ecdsa-sha2-nistp384,"
279 		    "ecdsa-sha2-nistp521";
280 		break;
281 	default:
282 		fatal("unknown key type %d", c->c_keytype);
283 		break;
284 	}
285 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
286 		free(c->c_ssh);
287 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
288 		exit(1);
289 	}
290 #ifdef WITH_OPENSSL
291 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
292 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
293 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
294 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
295 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
296 #endif
297 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
298 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
299 	/*
300 	 * do the key-exchange until an error occurs or until
301 	 * the key_print_wrapper() callback sets c_done.
302 	 */
303 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
304 }
305 
306 static void
307 keyprint_one(char *host, struct sshkey *key)
308 {
309 	char *hostport;
310 	int r;
311 
312 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
313 		fatal("host_hash failed");
314 
315 	hostport = put_host_port(host, ssh_port);
316 	if (!get_cert)
317 		fprintf(stdout, "%s ", hostport);
318 	if ((r = sshkey_write(key, stdout)) != 0)
319 		error("key_write failed: %s", ssh_err(r));
320 
321 	fputs("\n", stdout);
322 	free(hostport);
323 }
324 
325 static void
326 keyprint(con *c, struct sshkey *key)
327 {
328 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
329 	char *host, *ohosts;
330 
331 	if (key == NULL)
332 		return;
333 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
334 		keyprint_one(hosts, key);
335 		return;
336 	}
337 	ohosts = hosts = xstrdup(hosts);
338 	while ((host = strsep(&hosts, ",")) != NULL)
339 		keyprint_one(host, key);
340 	free(ohosts);
341 }
342 
343 static int
344 tcpconnect(char *host)
345 {
346 	struct addrinfo hints, *ai, *aitop;
347 	char strport[NI_MAXSERV];
348 	int gaierr, s = -1;
349 
350 	snprintf(strport, sizeof strport, "%d", ssh_port);
351 	memset(&hints, 0, sizeof(hints));
352 	hints.ai_family = IPv4or6;
353 	hints.ai_socktype = SOCK_STREAM;
354 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
355 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
356 		return -1;
357 	}
358 	for (ai = aitop; ai; ai = ai->ai_next) {
359 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
360 		if (s < 0) {
361 			error("socket: %s", strerror(errno));
362 			continue;
363 		}
364 		if (set_nonblock(s) == -1)
365 			fatal("%s: set_nonblock(%d)", __func__, s);
366 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
367 		    errno != EINPROGRESS)
368 			error("connect (`%s'): %s", host, strerror(errno));
369 		else
370 			break;
371 		close(s);
372 		s = -1;
373 	}
374 	freeaddrinfo(aitop);
375 	return s;
376 }
377 
378 static int
379 conalloc(char *iname, char *oname, int keytype)
380 {
381 	char *namebase, *name, *namelist;
382 	int s;
383 
384 	namebase = namelist = xstrdup(iname);
385 
386 	do {
387 		name = xstrsep(&namelist, ",");
388 		if (!name) {
389 			free(namebase);
390 			return (-1);
391 		}
392 	} while ((s = tcpconnect(name)) < 0);
393 
394 	if (s >= maxfd)
395 		fatal("conalloc: fdno %d too high", s);
396 	if (fdcon[s].c_status)
397 		fatal("conalloc: attempt to reuse fdno %d", s);
398 
399 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
400 	fdcon[s].c_fd = s;
401 	fdcon[s].c_status = CS_CON;
402 	fdcon[s].c_namebase = namebase;
403 	fdcon[s].c_name = name;
404 	fdcon[s].c_namelist = namelist;
405 	fdcon[s].c_output_name = xstrdup(oname);
406 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
407 	fdcon[s].c_len = 4;
408 	fdcon[s].c_off = 0;
409 	fdcon[s].c_keytype = keytype;
410 	gettimeofday(&fdcon[s].c_tv, NULL);
411 	fdcon[s].c_tv.tv_sec += timeout;
412 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
413 	FD_SET(s, read_wait);
414 	ncon++;
415 	return (s);
416 }
417 
418 static void
419 confree(int s)
420 {
421 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
422 		fatal("confree: attempt to free bad fdno %d", s);
423 	close(s);
424 	free(fdcon[s].c_namebase);
425 	free(fdcon[s].c_output_name);
426 	if (fdcon[s].c_status == CS_KEYS)
427 		free(fdcon[s].c_data);
428 	fdcon[s].c_status = CS_UNUSED;
429 	fdcon[s].c_keytype = 0;
430 	if (fdcon[s].c_ssh) {
431 		ssh_packet_close(fdcon[s].c_ssh);
432 		free(fdcon[s].c_ssh);
433 		fdcon[s].c_ssh = NULL;
434 	}
435 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
436 	FD_CLR(s, read_wait);
437 	ncon--;
438 }
439 
440 static void
441 contouch(int s)
442 {
443 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
444 	gettimeofday(&fdcon[s].c_tv, NULL);
445 	fdcon[s].c_tv.tv_sec += timeout;
446 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
447 }
448 
449 static int
450 conrecycle(int s)
451 {
452 	con *c = &fdcon[s];
453 	int ret;
454 
455 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
456 	confree(s);
457 	return (ret);
458 }
459 
460 static void
461 congreet(int s)
462 {
463 	int n = 0, remote_major = 0, remote_minor = 0;
464 	char buf[256], *cp;
465 	char remote_version[sizeof buf];
466 	size_t bufsiz;
467 	con *c = &fdcon[s];
468 
469 	for (;;) {
470 		memset(buf, '\0', sizeof(buf));
471 		bufsiz = sizeof(buf);
472 		cp = buf;
473 		while (bufsiz-- &&
474 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
475 			if (*cp == '\r')
476 				*cp = '\n';
477 			cp++;
478 		}
479 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
480 			break;
481 	}
482 	if (n == 0) {
483 		switch (errno) {
484 		case EPIPE:
485 			error("%s: Connection closed by remote host", c->c_name);
486 			break;
487 		case ECONNREFUSED:
488 			break;
489 		default:
490 			error("read (%s): %s", c->c_name, strerror(errno));
491 			break;
492 		}
493 		conrecycle(s);
494 		return;
495 	}
496 	if (*cp != '\n' && *cp != '\r') {
497 		error("%s: bad greeting", c->c_name);
498 		confree(s);
499 		return;
500 	}
501 	*cp = '\0';
502 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
503 		fatal("ssh_packet_set_connection failed");
504 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
505 	ssh_set_app_data(c->c_ssh, c);	/* back link */
506 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
507 	    &remote_major, &remote_minor, remote_version) == 3)
508 		c->c_ssh->compat = compat_datafellows(remote_version);
509 	else
510 		c->c_ssh->compat = 0;
511 	if (c->c_keytype != KT_RSA1) {
512 		if (!ssh2_capable(remote_major, remote_minor)) {
513 			debug("%s doesn't support ssh2", c->c_name);
514 			confree(s);
515 			return;
516 		}
517 	} else if (remote_major != 1) {
518 		debug("%s doesn't support ssh1", c->c_name);
519 		confree(s);
520 		return;
521 	}
522 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
523 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
524 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
525 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
526 	if (n < 0 || (size_t)n >= sizeof(buf)) {
527 		error("snprintf: buffer too small");
528 		confree(s);
529 		return;
530 	}
531 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
532 		error("write (%s): %s", c->c_name, strerror(errno));
533 		confree(s);
534 		return;
535 	}
536 	if (c->c_keytype != KT_RSA1) {
537 		keygrab_ssh2(c);
538 		confree(s);
539 		return;
540 	}
541 	c->c_status = CS_SIZE;
542 	contouch(s);
543 }
544 
545 static void
546 conread(int s)
547 {
548 	con *c = &fdcon[s];
549 	size_t n;
550 
551 	if (c->c_status == CS_CON) {
552 		congreet(s);
553 		return;
554 	}
555 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
556 	if (n == 0) {
557 		error("read (%s): %s", c->c_name, strerror(errno));
558 		confree(s);
559 		return;
560 	}
561 	c->c_off += n;
562 
563 	if (c->c_off == c->c_len)
564 		switch (c->c_status) {
565 		case CS_SIZE:
566 			c->c_plen = htonl(c->c_plen);
567 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
568 			c->c_off = 0;
569 			c->c_data = xmalloc(c->c_len);
570 			c->c_status = CS_KEYS;
571 			break;
572 #ifdef WITH_SSH1
573 		case CS_KEYS:
574 			keyprint(c, keygrab_ssh1(c));
575 			confree(s);
576 			return;
577 #endif
578 		default:
579 			fatal("conread: invalid status %d", c->c_status);
580 			break;
581 		}
582 
583 	contouch(s);
584 }
585 
586 static void
587 conloop(void)
588 {
589 	struct timeval seltime, now;
590 	fd_set *r, *e;
591 	con *c;
592 	int i;
593 
594 	gettimeofday(&now, NULL);
595 	c = TAILQ_FIRST(&tq);
596 
597 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
598 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
599 		seltime = c->c_tv;
600 		seltime.tv_sec -= now.tv_sec;
601 		seltime.tv_usec -= now.tv_usec;
602 		if (seltime.tv_usec < 0) {
603 			seltime.tv_usec += 1000000;
604 			seltime.tv_sec--;
605 		}
606 	} else
607 		timerclear(&seltime);
608 
609 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
610 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
611 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
612 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
613 
614 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
615 	    (errno == EAGAIN || errno == EINTR))
616 		;
617 
618 	for (i = 0; i < maxfd; i++) {
619 		if (FD_ISSET(i, e)) {
620 			error("%s: exception!", fdcon[i].c_name);
621 			confree(i);
622 		} else if (FD_ISSET(i, r))
623 			conread(i);
624 	}
625 	free(r);
626 	free(e);
627 
628 	c = TAILQ_FIRST(&tq);
629 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
630 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
631 		int s = c->c_fd;
632 
633 		c = TAILQ_NEXT(c, c_link);
634 		conrecycle(s);
635 	}
636 }
637 
638 static void
639 do_host(char *host)
640 {
641 	char *name = strnnsep(&host, " \t\n");
642 	int j;
643 
644 	if (name == NULL)
645 		return;
646 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
647 		if (get_keytypes & j) {
648 			while (ncon >= MAXCON)
649 				conloop();
650 			conalloc(name, *host ? host : name, j);
651 		}
652 	}
653 }
654 
655 __dead void
656 fatal(const char *fmt,...)
657 {
658 	va_list args;
659 
660 	va_start(args, fmt);
661 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
662 	va_end(args);
663 	exit(255);
664 }
665 
666 __dead static void
667 usage(void)
668 {
669 	fprintf(stderr,
670 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
671 	    "\t\t   [host | addrlist namelist] ...\n",
672 	    __progname);
673 	exit(1);
674 }
675 
676 int
677 main(int argc, char **argv)
678 {
679 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
680 	int opt, fopt_count = 0, j;
681 	char *tname, *cp, line[NI_MAXHOST];
682 	FILE *fp;
683 	u_long linenum;
684 
685 	extern int optind;
686 	extern char *optarg;
687 
688 	ssh_malloc_init();	/* must be called before any mallocs */
689 	TAILQ_INIT(&tq);
690 
691 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
692 	sanitise_stdfd();
693 
694 	if (argc <= 1)
695 		usage();
696 
697 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
698 		switch (opt) {
699 		case 'H':
700 			hash_hosts = 1;
701 			break;
702 		case 'c':
703 			get_cert = 1;
704 			break;
705 		case 'p':
706 			ssh_port = a2port(optarg);
707 			if (ssh_port <= 0) {
708 				fprintf(stderr, "Bad port '%s'\n", optarg);
709 				exit(1);
710 			}
711 			break;
712 		case 'T':
713 			timeout = convtime(optarg);
714 			if (timeout == -1 || timeout == 0) {
715 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
716 				usage();
717 			}
718 			break;
719 		case 'v':
720 			if (!debug_flag) {
721 				debug_flag = 1;
722 				log_level = SYSLOG_LEVEL_DEBUG1;
723 			}
724 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
725 				log_level++;
726 			else
727 				fatal("Too high debugging level.");
728 			break;
729 		case 'f':
730 			if (strcmp(optarg, "-") == 0)
731 				optarg = NULL;
732 			argv[fopt_count++] = optarg;
733 			break;
734 		case 't':
735 			get_keytypes = 0;
736 			tname = strtok(optarg, ",");
737 			while (tname) {
738 				int type = sshkey_type_from_name(tname);
739 				switch (type) {
740 				case KEY_RSA1:
741 					get_keytypes |= KT_RSA1;
742 					break;
743 				case KEY_DSA:
744 					get_keytypes |= KT_DSA;
745 					break;
746 				case KEY_ECDSA:
747 					get_keytypes |= KT_ECDSA;
748 					break;
749 				case KEY_RSA:
750 					get_keytypes |= KT_RSA;
751 					break;
752 				case KEY_ED25519:
753 					get_keytypes |= KT_ED25519;
754 					break;
755 				case KEY_UNSPEC:
756 					fatal("unknown key type %s", tname);
757 				}
758 				tname = strtok(NULL, ",");
759 			}
760 			break;
761 		case '4':
762 			IPv4or6 = AF_INET;
763 			break;
764 		case '6':
765 			IPv4or6 = AF_INET6;
766 			break;
767 		case '?':
768 		default:
769 			usage();
770 		}
771 	}
772 	if (optind == argc && !fopt_count)
773 		usage();
774 
775 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
776 
777 	maxfd = fdlim_get(1);
778 	if (maxfd < 0)
779 		fatal("%s: fdlim_get: bad value", __progname);
780 	if (maxfd > MAXMAXFD)
781 		maxfd = MAXMAXFD;
782 	if (MAXCON <= 0)
783 		fatal("%s: not enough file descriptors", __progname);
784 	if (maxfd > fdlim_get(0))
785 		fdlim_set(maxfd);
786 	fdcon = xcalloc(maxfd, sizeof(con));
787 
788 	read_wait_nfdset = howmany(maxfd, NFDBITS);
789 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
790 
791 	for (j = 0; j < fopt_count; j++) {
792 		if (argv[j] == NULL)
793 			fp = stdin;
794 		else if ((fp = fopen(argv[j], "r")) == NULL)
795 			fatal("%s: %s: %s", __progname, argv[j],
796 			    strerror(errno));
797 		linenum = 0;
798 
799 		while (read_keyfile_line(fp,
800 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
801 		    &linenum) != -1) {
802 			/* Chomp off trailing whitespace and comments */
803 			if ((cp = strchr(line, '#')) == NULL)
804 				cp = line + strlen(line) - 1;
805 			while (cp >= line) {
806 				if (*cp == ' ' || *cp == '\t' ||
807 				    *cp == '\n' || *cp == '#')
808 					*cp-- = '\0';
809 				else
810 					break;
811 			}
812 
813 			/* Skip empty lines */
814 			if (*line == '\0')
815 				continue;
816 
817 			do_host(line);
818 		}
819 
820 		if (ferror(fp))
821 			fatal("%s: %s: %s", __progname, argv[j],
822 			    strerror(errno));
823 
824 		fclose(fp);
825 	}
826 
827 	while (optind < argc)
828 		do_host(argv[optind++]);
829 
830 	while (ncon > 0)
831 		conloop();
832 
833 	return (0);
834 }
835