xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision d909946ca08dceb44d7d0f22ec9488679695d976)
1 /*	$NetBSD: ssh-keyscan.c,v 1.17 2016/08/02 13:45:12 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.106 2016/05/02 10:26:04 djm 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 1.17 2016/08/02 13:45:12 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 "ssh1.h"
35 #include "sshbuf.h"
36 #include "sshkey.h"
37 #include "cipher.h"
38 #include "kex.h"
39 #include "compat.h"
40 #include "myproposal.h"
41 #include "packet.h"
42 #include "dispatch.h"
43 #include "log.h"
44 #include "atomicio.h"
45 #include "misc.h"
46 #include "hostfile.h"
47 #include "ssherr.h"
48 #include "ssh_api.h"
49 
50 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
51    Default value is AF_UNSPEC means both IPv4 and IPv6. */
52 int IPv4or6 = AF_UNSPEC;
53 
54 int ssh_port = SSH_DEFAULT_PORT;
55 
56 #define KT_RSA1		1
57 #define KT_DSA		2
58 #define KT_RSA		4
59 #define KT_ECDSA	8
60 #define KT_ED25519	16
61 
62 int get_cert = 0;
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 /*
81  * Keep a connection structure for each file descriptor.  The state
82  * associated with file descriptor n is held in fdcon[n].
83  */
84 typedef struct Connection {
85 	u_char c_status;	/* State of connection on this file desc. */
86 #define CS_UNUSED 0		/* File descriptor unused */
87 #define CS_CON 1		/* Waiting to connect/read greeting */
88 #define CS_SIZE 2		/* Waiting to read initial packet size */
89 #define CS_KEYS 3		/* Waiting to read public key packet */
90 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
91 	int c_plen;		/* Packet length field for ssh packet */
92 	int c_len;		/* Total bytes which must be read. */
93 	int c_off;		/* Length of data read so far. */
94 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
95 	sig_atomic_t c_done;	/* SSH2 done */
96 	char *c_namebase;	/* Address to free for c_name and c_namelist */
97 	char *c_name;		/* Hostname of connection for errors */
98 	char *c_namelist;	/* Pointer to other possible addresses */
99 	char *c_output_name;	/* Hostname of connection for output */
100 	char *c_data;		/* Data read from this fd */
101 	struct ssh *c_ssh;	/* SSH-connection */
102 	struct timeval c_tv;	/* Time at which connection gets aborted */
103 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
104 } con;
105 
106 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
107 con *fdcon;
108 
109 static void keyprint(con *c, struct sshkey *key);
110 
111 static int
112 fdlim_get(int hard)
113 {
114 	struct rlimit rlfd;
115 
116 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
117 		return (-1);
118 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
119 		return sysconf(_SC_OPEN_MAX);
120 	else
121 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
122 }
123 
124 static int
125 fdlim_set(int lim)
126 {
127 	struct rlimit rlfd;
128 
129 	if (lim <= 0)
130 		return (-1);
131 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
132 		return (-1);
133 	rlfd.rlim_cur = lim;
134 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
135 		return (-1);
136 	return (0);
137 }
138 
139 /*
140  * This is an strsep function that returns a null field for adjacent
141  * separators.  This is the same as the 4.4BSD strsep, but different from the
142  * one in the GNU libc.
143  */
144 static char *
145 xstrsep(char **str, const char *delim)
146 {
147 	char *s, *e;
148 
149 	if (!**str)
150 		return (NULL);
151 
152 	s = *str;
153 	e = s + strcspn(s, delim);
154 
155 	if (*e != '\0')
156 		*e++ = '\0';
157 	*str = e;
158 
159 	return (s);
160 }
161 
162 /*
163  * Get the next non-null token (like GNU strsep).  Strsep() will return a
164  * null token for two adjacent separators, so we may have to loop.
165  */
166 static char *
167 strnnsep(char **stringp, const char *delim)
168 {
169 	char *tok;
170 
171 	do {
172 		tok = xstrsep(stringp, delim);
173 	} while (tok && *tok == '\0');
174 	return (tok);
175 }
176 
177 #ifdef WITH_SSH1
178 static struct sshkey *
179 keygrab_ssh1(con *c)
180 {
181 	static struct sshkey *rsa;
182 	static struct sshbuf *msg;
183 	int r;
184 	u_char type;
185 
186 	if (rsa == NULL) {
187 		if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
188 			error("%s: sshkey_new failed", __func__);
189 			return NULL;
190 		}
191 		if ((msg = sshbuf_new()) == NULL)
192 			fatal("%s: sshbuf_new failed", __func__);
193 	}
194 	if ((r = sshbuf_put(msg, c->c_data, c->c_plen)) != 0 ||
195 	    (r = sshbuf_consume(msg, 8 - (c->c_plen & 7))) != 0 || /* padding */
196 	    (r = sshbuf_get_u8(msg, &type)) != 0)
197 		goto buf_err;
198 	if (type != (int) SSH_SMSG_PUBLIC_KEY) {
199 		error("%s: invalid packet type", c->c_name);
200 		sshbuf_reset(msg);
201 		return NULL;
202 	}
203 	if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
204 	    /* server key */
205 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
206 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
207 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
208 	    /* host key */
209 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
210 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->e)) != 0 ||
211 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->n)) != 0) {
212  buf_err:
213 		error("%s: buffer error: %s", __func__, ssh_err(r));
214 		sshbuf_reset(msg);
215 		return NULL;
216 	}
217 
218 	sshbuf_reset(msg);
219 
220 	return (rsa);
221 }
222 #endif
223 
224 static int
225 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
226 {
227 	con *c;
228 
229 	if ((c = ssh_get_app_data(ssh)) != NULL)
230 		keyprint(c, hostkey);
231 	/* always abort key exchange */
232 	return -1;
233 }
234 
235 static int
236 ssh2_capable(int remote_major, int remote_minor)
237 {
238 	switch (remote_major) {
239 	case 1:
240 		if (remote_minor == 99)
241 			return 1;
242 		break;
243 	case 2:
244 		return 1;
245 	default:
246 		break;
247 	}
248 	return 0;
249 }
250 
251 static void
252 keygrab_ssh2(con *c)
253 {
254 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
255 	int r;
256 
257 	enable_compat20();
258 	switch (c->c_keytype) {
259 	case KT_DSA:
260 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
261 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
262 		break;
263 	case KT_RSA:
264 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
265 		    "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
266 		break;
267 	case KT_ED25519:
268 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
269 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
270 		break;
271 	case KT_ECDSA:
272 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
273 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
274 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
275 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
276 		    "ecdsa-sha2-nistp256,"
277 		    "ecdsa-sha2-nistp384,"
278 		    "ecdsa-sha2-nistp521";
279 		break;
280 	default:
281 		fatal("unknown key type %d", c->c_keytype);
282 		break;
283 	}
284 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
285 		free(c->c_ssh);
286 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
287 		exit(1);
288 	}
289 #ifdef WITH_OPENSSL
290 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
291 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
292 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
293 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
294 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
295 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
296 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
297 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
298 #endif
299 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
300 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
301 	/*
302 	 * do the key-exchange until an error occurs or until
303 	 * the key_print_wrapper() callback sets c_done.
304 	 */
305 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
306 }
307 
308 static void
309 keyprint_one(char *host, struct sshkey *key)
310 {
311 	char *hostport;
312 	int r;
313 
314 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
315 		fatal("host_hash failed");
316 
317 	hostport = put_host_port(host, ssh_port);
318 	if (!get_cert)
319 		fprintf(stdout, "%s ", hostport);
320 	if ((r = sshkey_write(key, stdout)) != 0)
321 		error("key_write failed: %s", ssh_err(r));
322 
323 	fputs("\n", stdout);
324 	free(hostport);
325 }
326 
327 static void
328 keyprint(con *c, struct sshkey *key)
329 {
330 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
331 	char *host, *ohosts;
332 
333 	if (key == NULL)
334 		return;
335 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
336 		keyprint_one(hosts, key);
337 		return;
338 	}
339 	ohosts = hosts = xstrdup(hosts);
340 	while ((host = strsep(&hosts, ",")) != NULL)
341 		keyprint_one(host, key);
342 	free(ohosts);
343 }
344 
345 static int
346 tcpconnect(char *host)
347 {
348 	struct addrinfo hints, *ai, *aitop;
349 	char strport[NI_MAXSERV];
350 	int gaierr, s = -1;
351 
352 	snprintf(strport, sizeof strport, "%d", ssh_port);
353 	memset(&hints, 0, sizeof(hints));
354 	hints.ai_family = IPv4or6;
355 	hints.ai_socktype = SOCK_STREAM;
356 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
357 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
358 		return -1;
359 	}
360 	for (ai = aitop; ai; ai = ai->ai_next) {
361 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
362 		if (s < 0) {
363 			error("socket: %s", strerror(errno));
364 			continue;
365 		}
366 		if (set_nonblock(s) == -1)
367 			fatal("%s: set_nonblock(%d)", __func__, s);
368 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
369 		    errno != EINPROGRESS)
370 			error("connect (`%s'): %s", host, strerror(errno));
371 		else
372 			break;
373 		close(s);
374 		s = -1;
375 	}
376 	freeaddrinfo(aitop);
377 	return s;
378 }
379 
380 static int
381 conalloc(char *iname, char *oname, int keytype)
382 {
383 	char *namebase, *name, *namelist;
384 	int s;
385 
386 	namebase = namelist = xstrdup(iname);
387 
388 	do {
389 		name = xstrsep(&namelist, ",");
390 		if (!name) {
391 			free(namebase);
392 			return (-1);
393 		}
394 	} while ((s = tcpconnect(name)) < 0);
395 
396 	if (s >= maxfd)
397 		fatal("conalloc: fdno %d too high", s);
398 	if (fdcon[s].c_status)
399 		fatal("conalloc: attempt to reuse fdno %d", s);
400 
401 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
402 	fdcon[s].c_fd = s;
403 	fdcon[s].c_status = CS_CON;
404 	fdcon[s].c_namebase = namebase;
405 	fdcon[s].c_name = name;
406 	fdcon[s].c_namelist = namelist;
407 	fdcon[s].c_output_name = xstrdup(oname);
408 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
409 	fdcon[s].c_len = 4;
410 	fdcon[s].c_off = 0;
411 	fdcon[s].c_keytype = keytype;
412 	gettimeofday(&fdcon[s].c_tv, NULL);
413 	fdcon[s].c_tv.tv_sec += timeout;
414 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
415 	FD_SET(s, read_wait);
416 	ncon++;
417 	return (s);
418 }
419 
420 static void
421 confree(int s)
422 {
423 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
424 		fatal("confree: attempt to free bad fdno %d", s);
425 	close(s);
426 	free(fdcon[s].c_namebase);
427 	free(fdcon[s].c_output_name);
428 	if (fdcon[s].c_status == CS_KEYS)
429 		free(fdcon[s].c_data);
430 	fdcon[s].c_status = CS_UNUSED;
431 	fdcon[s].c_keytype = 0;
432 	if (fdcon[s].c_ssh) {
433 		ssh_packet_close(fdcon[s].c_ssh);
434 		free(fdcon[s].c_ssh);
435 		fdcon[s].c_ssh = NULL;
436 	}
437 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
438 	FD_CLR(s, read_wait);
439 	ncon--;
440 }
441 
442 static void
443 contouch(int s)
444 {
445 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
446 	gettimeofday(&fdcon[s].c_tv, NULL);
447 	fdcon[s].c_tv.tv_sec += timeout;
448 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
449 }
450 
451 static int
452 conrecycle(int s)
453 {
454 	con *c = &fdcon[s];
455 	int ret;
456 
457 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
458 	confree(s);
459 	return (ret);
460 }
461 
462 static void
463 congreet(int s)
464 {
465 	int n = 0, remote_major = 0, remote_minor = 0;
466 	char buf[256], *cp;
467 	char remote_version[sizeof buf];
468 	size_t bufsiz;
469 	con *c = &fdcon[s];
470 
471 	for (;;) {
472 		memset(buf, '\0', sizeof(buf));
473 		bufsiz = sizeof(buf);
474 		cp = buf;
475 		while (bufsiz-- &&
476 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
477 			if (*cp == '\r')
478 				*cp = '\n';
479 			cp++;
480 		}
481 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
482 			break;
483 	}
484 	if (n == 0) {
485 		switch (errno) {
486 		case EPIPE:
487 			error("%s: Connection closed by remote host", c->c_name);
488 			break;
489 		case ECONNREFUSED:
490 			break;
491 		default:
492 			error("read (%s): %s", c->c_name, strerror(errno));
493 			break;
494 		}
495 		conrecycle(s);
496 		return;
497 	}
498 	if (*cp != '\n' && *cp != '\r') {
499 		error("%s: bad greeting", c->c_name);
500 		confree(s);
501 		return;
502 	}
503 	*cp = '\0';
504 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
505 		fatal("ssh_packet_set_connection failed");
506 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
507 	ssh_set_app_data(c->c_ssh, c);	/* back link */
508 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
509 	    &remote_major, &remote_minor, remote_version) == 3)
510 		c->c_ssh->compat = compat_datafellows(remote_version);
511 	else
512 		c->c_ssh->compat = 0;
513 	if (c->c_keytype != KT_RSA1) {
514 		if (!ssh2_capable(remote_major, remote_minor)) {
515 			debug("%s doesn't support ssh2", c->c_name);
516 			confree(s);
517 			return;
518 		}
519 	} else if (remote_major != 1) {
520 		debug("%s doesn't support ssh1", c->c_name);
521 		confree(s);
522 		return;
523 	}
524 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
525 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
526 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
527 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
528 	if (n < 0 || (size_t)n >= sizeof(buf)) {
529 		error("snprintf: buffer too small");
530 		confree(s);
531 		return;
532 	}
533 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
534 		error("write (%s): %s", c->c_name, strerror(errno));
535 		confree(s);
536 		return;
537 	}
538 	if (c->c_keytype != KT_RSA1) {
539 		keygrab_ssh2(c);
540 		confree(s);
541 		return;
542 	}
543 	c->c_status = CS_SIZE;
544 	contouch(s);
545 }
546 
547 static void
548 conread(int s)
549 {
550 	con *c = &fdcon[s];
551 	size_t n;
552 
553 	if (c->c_status == CS_CON) {
554 		congreet(s);
555 		return;
556 	}
557 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
558 	if (n == 0) {
559 		error("read (%s): %s", c->c_name, strerror(errno));
560 		confree(s);
561 		return;
562 	}
563 	c->c_off += n;
564 
565 	if (c->c_off == c->c_len)
566 		switch (c->c_status) {
567 		case CS_SIZE:
568 			c->c_plen = htonl(c->c_plen);
569 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
570 			c->c_off = 0;
571 			c->c_data = xmalloc(c->c_len);
572 			c->c_status = CS_KEYS;
573 			break;
574 #ifdef WITH_SSH1
575 		case CS_KEYS:
576 			keyprint(c, keygrab_ssh1(c));
577 			confree(s);
578 			return;
579 #endif
580 		default:
581 			fatal("conread: invalid status %d", c->c_status);
582 			break;
583 		}
584 
585 	contouch(s);
586 }
587 
588 static void
589 conloop(void)
590 {
591 	struct timeval seltime, now;
592 	fd_set *r, *e;
593 	con *c;
594 	int i;
595 
596 	gettimeofday(&now, NULL);
597 	c = TAILQ_FIRST(&tq);
598 
599 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
600 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
601 		seltime = c->c_tv;
602 		seltime.tv_sec -= now.tv_sec;
603 		seltime.tv_usec -= now.tv_usec;
604 		if (seltime.tv_usec < 0) {
605 			seltime.tv_usec += 1000000;
606 			seltime.tv_sec--;
607 		}
608 	} else
609 		timerclear(&seltime);
610 
611 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
612 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
613 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
614 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
615 
616 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
617 	    (errno == EAGAIN || errno == EINTR))
618 		;
619 
620 	for (i = 0; i < maxfd; i++) {
621 		if (FD_ISSET(i, e)) {
622 			error("%s: exception!", fdcon[i].c_name);
623 			confree(i);
624 		} else if (FD_ISSET(i, r))
625 			conread(i);
626 	}
627 	free(r);
628 	free(e);
629 
630 	c = TAILQ_FIRST(&tq);
631 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
632 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
633 		int s = c->c_fd;
634 
635 		c = TAILQ_NEXT(c, c_link);
636 		conrecycle(s);
637 	}
638 }
639 
640 static void
641 do_host(char *host)
642 {
643 	char *name = strnnsep(&host, " \t\n");
644 	int j;
645 
646 	if (name == NULL)
647 		return;
648 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
649 		if (get_keytypes & j) {
650 			while (ncon >= MAXCON)
651 				conloop();
652 			conalloc(name, *host ? host : name, j);
653 		}
654 	}
655 }
656 
657 __dead void
658 fatal(const char *fmt,...)
659 {
660 	va_list args;
661 
662 	va_start(args, fmt);
663 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
664 	va_end(args);
665 	exit(255);
666 }
667 
668 __dead static void
669 usage(void)
670 {
671 	fprintf(stderr,
672 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
673 	    "\t\t   [host | addrlist namelist] ...\n",
674 	    __progname);
675 	exit(1);
676 }
677 
678 int
679 main(int argc, char **argv)
680 {
681 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
682 	int opt, fopt_count = 0, j;
683 	char *tname, *cp, line[NI_MAXHOST];
684 	FILE *fp;
685 	u_long linenum;
686 
687 	extern int optind;
688 	extern char *optarg;
689 
690 	ssh_malloc_init();	/* must be called before any mallocs */
691 	TAILQ_INIT(&tq);
692 
693 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
694 	sanitise_stdfd();
695 
696 	if (argc <= 1)
697 		usage();
698 
699 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
700 		switch (opt) {
701 		case 'H':
702 			hash_hosts = 1;
703 			break;
704 		case 'c':
705 			get_cert = 1;
706 			break;
707 		case 'p':
708 			ssh_port = a2port(optarg);
709 			if (ssh_port <= 0) {
710 				fprintf(stderr, "Bad port '%s'\n", optarg);
711 				exit(1);
712 			}
713 			break;
714 		case 'T':
715 			timeout = convtime(optarg);
716 			if (timeout == -1 || timeout == 0) {
717 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
718 				usage();
719 			}
720 			break;
721 		case 'v':
722 			if (!debug_flag) {
723 				debug_flag = 1;
724 				log_level = SYSLOG_LEVEL_DEBUG1;
725 			}
726 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
727 				log_level++;
728 			else
729 				fatal("Too high debugging level.");
730 			break;
731 		case 'f':
732 			if (strcmp(optarg, "-") == 0)
733 				optarg = NULL;
734 			argv[fopt_count++] = optarg;
735 			break;
736 		case 't':
737 			get_keytypes = 0;
738 			tname = strtok(optarg, ",");
739 			while (tname) {
740 				int type = sshkey_type_from_name(tname);
741 				switch (type) {
742 				case KEY_RSA1:
743 					get_keytypes |= KT_RSA1;
744 					break;
745 				case KEY_DSA:
746 					get_keytypes |= KT_DSA;
747 					break;
748 				case KEY_ECDSA:
749 					get_keytypes |= KT_ECDSA;
750 					break;
751 				case KEY_RSA:
752 					get_keytypes |= KT_RSA;
753 					break;
754 				case KEY_ED25519:
755 					get_keytypes |= KT_ED25519;
756 					break;
757 				case KEY_UNSPEC:
758 					fatal("unknown key type %s", tname);
759 				}
760 				tname = strtok(NULL, ",");
761 			}
762 			break;
763 		case '4':
764 			IPv4or6 = AF_INET;
765 			break;
766 		case '6':
767 			IPv4or6 = AF_INET6;
768 			break;
769 		case '?':
770 		default:
771 			usage();
772 		}
773 	}
774 	if (optind == argc && !fopt_count)
775 		usage();
776 
777 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
778 
779 	maxfd = fdlim_get(1);
780 	if (maxfd < 0)
781 		fatal("%s: fdlim_get: bad value", __progname);
782 	if (maxfd > MAXMAXFD)
783 		maxfd = MAXMAXFD;
784 	if (MAXCON <= 0)
785 		fatal("%s: not enough file descriptors", __progname);
786 	if (maxfd > fdlim_get(0))
787 		fdlim_set(maxfd);
788 	fdcon = xcalloc(maxfd, sizeof(con));
789 
790 	read_wait_nfdset = howmany(maxfd, NFDBITS);
791 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
792 
793 	for (j = 0; j < fopt_count; j++) {
794 		if (argv[j] == NULL)
795 			fp = stdin;
796 		else if ((fp = fopen(argv[j], "r")) == NULL)
797 			fatal("%s: %s: %s", __progname, argv[j],
798 			    strerror(errno));
799 		linenum = 0;
800 
801 		while (read_keyfile_line(fp,
802 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
803 		    &linenum) != -1) {
804 			/* Chomp off trailing whitespace and comments */
805 			if ((cp = strchr(line, '#')) == NULL)
806 				cp = line + strlen(line) - 1;
807 			while (cp >= line) {
808 				if (*cp == ' ' || *cp == '\t' ||
809 				    *cp == '\n' || *cp == '#')
810 					*cp-- = '\0';
811 				else
812 					break;
813 			}
814 
815 			/* Skip empty lines */
816 			if (*line == '\0')
817 				continue;
818 
819 			do_host(line);
820 		}
821 
822 		if (ferror(fp))
823 			fatal("%s: %s: %s", __progname, argv[j],
824 			    strerror(errno));
825 
826 		fclose(fp);
827 	}
828 
829 	while (optind < argc)
830 		do_host(argv[optind++]);
831 
832 	while (ncon > 0)
833 		conloop();
834 
835 	return (0);
836 }
837