xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f) 
1 /*	$NetBSD: ssh-keyscan.c,v 1.26 2020/02/27 00:24:40 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.131 2019/12/15 19:47:10 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 1.26 2020/02/27 00:24:40 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 #ifdef WITH_OPENSSL
22 #include <openssl/bn.h>
23 #endif
24 
25 #include <errno.h>
26 #include <netdb.h>
27 #include <stdarg.h>
28 #include <stdio.h>
29 #include <stdlib.h>
30 #include <signal.h>
31 #include <string.h>
32 #include <unistd.h>
33 
34 #include "xmalloc.h"
35 #include "ssh.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 #include "dns.h"
51 
52 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
53    Default value is AF_UNSPEC means both IPv4 and IPv6. */
54 int IPv4or6 = AF_UNSPEC;
55 
56 int ssh_port = SSH_DEFAULT_PORT;
57 
58 #define KT_DSA		(1)
59 #define KT_RSA		(1<<1)
60 #define KT_ECDSA	(1<<2)
61 #define KT_ED25519	(1<<3)
62 #define KT_XMSS		(1<<4)
63 #define KT_ECDSA_SK	(1<<5)
64 #define KT_ED25519_SK	(1<<6)
65 
66 #define KT_MIN		KT_DSA
67 #define KT_MAX		KT_ED25519_SK
68 
69 int get_cert = 0;
70 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
71 
72 int hash_hosts = 0;		/* Hash hostname on output */
73 
74 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
75 
76 int found_one = 0;		/* Successfully found a key */
77 
78 #define MAXMAXFD 256
79 
80 /* The number of seconds after which to give up on a TCP connection */
81 int timeout = 5;
82 
83 int maxfd;
84 #define MAXCON (maxfd - 10)
85 
86 extern char *__progname;
87 fd_set *read_wait;
88 size_t read_wait_nfdset;
89 int ncon;
90 
91 /*
92  * Keep a connection structure for each file descriptor.  The state
93  * associated with file descriptor n is held in fdcon[n].
94  */
95 typedef struct Connection {
96 	u_char c_status;	/* State of connection on this file desc. */
97 #define CS_UNUSED 0		/* File descriptor unused */
98 #define CS_CON 1		/* Waiting to connect/read greeting */
99 #define CS_SIZE 2		/* Waiting to read initial packet size */
100 #define CS_KEYS 3		/* Waiting to read public key packet */
101 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
102 	int c_plen;		/* Packet length field for ssh packet */
103 	int c_len;		/* Total bytes which must be read. */
104 	int c_off;		/* Length of data read so far. */
105 	int c_keytype;		/* Only one of KT_* */
106 	sig_atomic_t c_done;	/* SSH2 done */
107 	char *c_namebase;	/* Address to free for c_name and c_namelist */
108 	char *c_name;		/* Hostname of connection for errors */
109 	char *c_namelist;	/* Pointer to other possible addresses */
110 	char *c_output_name;	/* Hostname of connection for output */
111 	char *c_data;		/* Data read from this fd */
112 	struct ssh *c_ssh;	/* SSH-connection */
113 	struct timeval c_tv;	/* Time at which connection gets aborted */
114 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
115 } con;
116 
117 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
118 con *fdcon;
119 
120 static void keyprint(con *c, struct sshkey *key);
121 
122 static int
123 fdlim_get(int hard)
124 {
125 	struct rlimit rlfd;
126 
127 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
128 		return (-1);
129 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
130 		return sysconf(_SC_OPEN_MAX);
131 	else
132 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
133 }
134 
135 static int
136 fdlim_set(int lim)
137 {
138 	struct rlimit rlfd;
139 
140 	if (lim <= 0)
141 		return (-1);
142 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
143 		return (-1);
144 	rlfd.rlim_cur = lim;
145 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
146 		return (-1);
147 	return (0);
148 }
149 
150 /*
151  * This is an strsep function that returns a null field for adjacent
152  * separators.  This is the same as the 4.4BSD strsep, but different from the
153  * one in the GNU libc.
154  */
155 static char *
156 xstrsep(char **str, const char *delim)
157 {
158 	char *s, *e;
159 
160 	if (!**str)
161 		return (NULL);
162 
163 	s = *str;
164 	e = s + strcspn(s, delim);
165 
166 	if (*e != '\0')
167 		*e++ = '\0';
168 	*str = e;
169 
170 	return (s);
171 }
172 
173 /*
174  * Get the next non-null token (like GNU strsep).  Strsep() will return a
175  * null token for two adjacent separators, so we may have to loop.
176  */
177 static char *
178 strnnsep(char **stringp, const char *delim)
179 {
180 	char *tok;
181 
182 	do {
183 		tok = xstrsep(stringp, delim);
184 	} while (tok && *tok == '\0');
185 	return (tok);
186 }
187 
188 
189 static int
190 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
191 {
192 	con *c;
193 
194 	if ((c = ssh_get_app_data(ssh)) != NULL)
195 		keyprint(c, hostkey);
196 	/* always abort key exchange */
197 	return -1;
198 }
199 
200 static int
201 ssh2_capable(int remote_major, int remote_minor)
202 {
203 	switch (remote_major) {
204 	case 1:
205 		if (remote_minor == 99)
206 			return 1;
207 		break;
208 	case 2:
209 		return 1;
210 	default:
211 		break;
212 	}
213 	return 0;
214 }
215 
216 static void
217 keygrab_ssh2(con *c)
218 {
219 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
220 	int r;
221 
222 	switch (c->c_keytype) {
223 	case KT_DSA:
224 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
225 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
226 		break;
227 	case KT_RSA:
228 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
229 		    "rsa-sha2-512-cert-v01@openssh.com,"
230 		    "rsa-sha2-256-cert-v01@openssh.com,"
231 		    "ssh-rsa-cert-v01@openssh.com" :
232 		    "rsa-sha2-512,"
233 		    "rsa-sha2-256,"
234 		    "ssh-rsa";
235 		break;
236 	case KT_ED25519:
237 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
238 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
239 		break;
240 	case KT_XMSS:
241 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
242 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
243 		break;
244 	case KT_ECDSA:
245 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
246 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
247 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
248 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
249 		    "ecdsa-sha2-nistp256,"
250 		    "ecdsa-sha2-nistp384,"
251 		    "ecdsa-sha2-nistp521";
252 		break;
253 	case KT_ECDSA_SK:
254 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
255 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
256 		    "sk-ecdsa-sha2-nistp256@openssh.com";
257 		break;
258 	case KT_ED25519_SK:
259 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
260 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
261 		    "sk-ssh-ed25519@openssh.com";
262 		break;
263 	default:
264 		fatal("unknown key type %d", c->c_keytype);
265 		break;
266 	}
267 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
268 		free(c->c_ssh);
269 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
270 		exit(1);
271 	}
272 #ifdef WITH_OPENSSL
273 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
274 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
275 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
276 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
277 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
278 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
279 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
280 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
281 #endif
282 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
283 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_client;
284 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
285 	/*
286 	 * do the key-exchange until an error occurs or until
287 	 * the key_print_wrapper() callback sets c_done.
288 	 */
289 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
290 }
291 
292 static void
293 keyprint_one(const char *host, struct sshkey *key)
294 {
295 	char *hostport;
296 	const char *known_host, *hashed;
297 
298 	found_one = 1;
299 
300 	if (print_sshfp) {
301 		export_dns_rr(host, key, stdout, 0);
302 		return;
303 	}
304 
305 	hostport = put_host_port(host, ssh_port);
306 	lowercase(hostport);
307 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
308 		fatal("host_hash failed");
309 	known_host = hash_hosts ? hashed : hostport;
310 	if (!get_cert)
311 		fprintf(stdout, "%s ", known_host);
312 	sshkey_write(key, stdout);
313 	fputs("\n", stdout);
314 	free(hostport);
315 }
316 
317 static void
318 keyprint(con *c, struct sshkey *key)
319 {
320 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
321 	char *host, *ohosts;
322 
323 	if (key == NULL)
324 		return;
325 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
326 		keyprint_one(hosts, key);
327 		return;
328 	}
329 	ohosts = hosts = xstrdup(hosts);
330 	while ((host = strsep(&hosts, ",")) != NULL)
331 		keyprint_one(host, key);
332 	free(ohosts);
333 }
334 
335 static int
336 tcpconnect(char *host)
337 {
338 	struct addrinfo hints, *ai, *aitop;
339 	char strport[NI_MAXSERV];
340 	int gaierr, s = -1;
341 
342 	snprintf(strport, sizeof strport, "%d", ssh_port);
343 	memset(&hints, 0, sizeof(hints));
344 	hints.ai_family = IPv4or6;
345 	hints.ai_socktype = SOCK_STREAM;
346 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
347 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
348 		return -1;
349 	}
350 	for (ai = aitop; ai; ai = ai->ai_next) {
351 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
352 		if (s == -1) {
353 			error("socket: %s", strerror(errno));
354 			continue;
355 		}
356 		if (set_nonblock(s) == -1)
357 			fatal("%s: set_nonblock(%d)", __func__, s);
358 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
359 		    errno != EINPROGRESS)
360 			error("connect (`%s'): %s", host, strerror(errno));
361 		else
362 			break;
363 		close(s);
364 		s = -1;
365 	}
366 	freeaddrinfo(aitop);
367 	return s;
368 }
369 
370 static int
371 conalloc(char *iname, char *oname, int keytype)
372 {
373 	char *namebase, *name, *namelist;
374 	int s;
375 
376 	namebase = namelist = xstrdup(iname);
377 
378 	do {
379 		name = xstrsep(&namelist, ",");
380 		if (!name) {
381 			free(namebase);
382 			return (-1);
383 		}
384 	} while ((s = tcpconnect(name)) < 0);
385 
386 	if (s >= maxfd)
387 		fatal("conalloc: fdno %d too high", s);
388 	if (fdcon[s].c_status)
389 		fatal("conalloc: attempt to reuse fdno %d", s);
390 
391 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
392 	fdcon[s].c_fd = s;
393 	fdcon[s].c_status = CS_CON;
394 	fdcon[s].c_namebase = namebase;
395 	fdcon[s].c_name = name;
396 	fdcon[s].c_namelist = namelist;
397 	fdcon[s].c_output_name = xstrdup(oname);
398 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
399 	fdcon[s].c_len = 4;
400 	fdcon[s].c_off = 0;
401 	fdcon[s].c_keytype = keytype;
402 	monotime_tv(&fdcon[s].c_tv);
403 	fdcon[s].c_tv.tv_sec += timeout;
404 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
405 	FD_SET(s, read_wait);
406 	ncon++;
407 	return (s);
408 }
409 
410 static void
411 confree(int s)
412 {
413 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
414 		fatal("confree: attempt to free bad fdno %d", s);
415 	free(fdcon[s].c_namebase);
416 	free(fdcon[s].c_output_name);
417 	if (fdcon[s].c_status == CS_KEYS)
418 		free(fdcon[s].c_data);
419 	fdcon[s].c_status = CS_UNUSED;
420 	fdcon[s].c_keytype = 0;
421 	if (fdcon[s].c_ssh) {
422 		ssh_packet_close(fdcon[s].c_ssh);
423 		free(fdcon[s].c_ssh);
424 		fdcon[s].c_ssh = NULL;
425 	} else
426 		close(s);
427 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
428 	FD_CLR(s, read_wait);
429 	ncon--;
430 }
431 
432 static void
433 contouch(int s)
434 {
435 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
436 	monotime_tv(&fdcon[s].c_tv);
437 	fdcon[s].c_tv.tv_sec += timeout;
438 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
439 }
440 
441 static int
442 conrecycle(int s)
443 {
444 	con *c = &fdcon[s];
445 	int ret;
446 
447 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
448 	confree(s);
449 	return (ret);
450 }
451 
452 static void
453 congreet(int s)
454 {
455 	int n = 0, remote_major = 0, remote_minor = 0;
456 	char buf[256], *cp;
457 	char remote_version[sizeof buf];
458 	size_t bufsiz;
459 	con *c = &fdcon[s];
460 
461 	/* send client banner */
462 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
463 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
464 	if (n < 0 || (size_t)n >= sizeof(buf)) {
465 		error("snprintf: buffer too small");
466 		confree(s);
467 		return;
468 	}
469 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
470 		error("write (%s): %s", c->c_name, strerror(errno));
471 		confree(s);
472 		return;
473 	}
474 
475 	for (;;) {
476 		memset(buf, '\0', sizeof(buf));
477 		bufsiz = sizeof(buf);
478 		cp = buf;
479 		while (bufsiz-- &&
480 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
481 			if (*cp == '\r')
482 				*cp = '\n';
483 			cp++;
484 		}
485 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
486 			break;
487 	}
488 	if (n == 0) {
489 		switch (errno) {
490 		case EPIPE:
491 			error("%s: Connection closed by remote host", c->c_name);
492 			break;
493 		case ECONNREFUSED:
494 			break;
495 		default:
496 			error("read (%s): %s", c->c_name, strerror(errno));
497 			break;
498 		}
499 		conrecycle(s);
500 		return;
501 	}
502 	if (*cp != '\n' && *cp != '\r') {
503 		error("%s: bad greeting", c->c_name);
504 		confree(s);
505 		return;
506 	}
507 	*cp = '\0';
508 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
509 		fatal("ssh_packet_set_connection failed");
510 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
511 	ssh_set_app_data(c->c_ssh, c);	/* back link */
512 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
513 	    &remote_major, &remote_minor, remote_version) == 3)
514 		c->c_ssh->compat = compat_datafellows(remote_version);
515 	else
516 		c->c_ssh->compat = 0;
517 	if (!ssh2_capable(remote_major, remote_minor)) {
518 		debug("%s doesn't support ssh2", c->c_name);
519 		confree(s);
520 		return;
521 	}
522 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
523 	    c->c_name, ssh_port, chop(buf));
524 	keygrab_ssh2(c);
525 	confree(s);
526 }
527 
528 static void
529 conread(int s)
530 {
531 	con *c = &fdcon[s];
532 	size_t n;
533 
534 	if (c->c_status == CS_CON) {
535 		congreet(s);
536 		return;
537 	}
538 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
539 	if (n == 0) {
540 		error("read (%s): %s", c->c_name, strerror(errno));
541 		confree(s);
542 		return;
543 	}
544 	c->c_off += n;
545 
546 	if (c->c_off == c->c_len)
547 		switch (c->c_status) {
548 		case CS_SIZE:
549 			c->c_plen = htonl(c->c_plen);
550 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
551 			c->c_off = 0;
552 			c->c_data = xmalloc(c->c_len);
553 			c->c_status = CS_KEYS;
554 			break;
555 		default:
556 			fatal("conread: invalid status %d", c->c_status);
557 			break;
558 		}
559 
560 	contouch(s);
561 }
562 
563 static void
564 conloop(void)
565 {
566 	struct timeval seltime, now;
567 	fd_set *r, *e;
568 	con *c;
569 	int i;
570 
571 	monotime_tv(&now);
572 	c = TAILQ_FIRST(&tq);
573 
574 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
575 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
576 		seltime = c->c_tv;
577 		seltime.tv_sec -= now.tv_sec;
578 		seltime.tv_usec -= now.tv_usec;
579 		if (seltime.tv_usec < 0) {
580 			seltime.tv_usec += 1000000;
581 			seltime.tv_sec--;
582 		}
583 	} else
584 		timerclear(&seltime);
585 
586 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
587 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
588 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
589 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
590 
591 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
592 	    (errno == EAGAIN || errno == EINTR))
593 		;
594 
595 	for (i = 0; i < maxfd; i++) {
596 		if (FD_ISSET(i, e)) {
597 			error("%s: exception!", fdcon[i].c_name);
598 			confree(i);
599 		} else if (FD_ISSET(i, r))
600 			conread(i);
601 	}
602 	free(r);
603 	free(e);
604 
605 	c = TAILQ_FIRST(&tq);
606 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
607 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
608 		int s = c->c_fd;
609 
610 		c = TAILQ_NEXT(c, c_link);
611 		conrecycle(s);
612 	}
613 }
614 
615 static void
616 do_host(char *host)
617 {
618 	char *name = strnnsep(&host, " \t\n");
619 	int j;
620 
621 	if (name == NULL)
622 		return;
623 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
624 		if (get_keytypes & j) {
625 			while (ncon >= MAXCON)
626 				conloop();
627 			conalloc(name, *host ? host : name, j);
628 		}
629 	}
630 }
631 
632 __dead void
633 fatal(const char *fmt,...)
634 {
635 	va_list args;
636 
637 	va_start(args, fmt);
638 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
639 	va_end(args);
640 	exit(255);
641 }
642 
643 __dead static void
644 usage(void)
645 {
646 	fprintf(stderr,
647 	    "usage: %s [-46cDHv] [-f file] [-p port] [-T timeout] [-t type]\n"
648 	    "\t\t   [host | addrlist namelist]\n",
649 	    __progname);
650 	exit(1);
651 }
652 
653 int
654 main(int argc, char **argv)
655 {
656 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
657 	int opt, fopt_count = 0, j;
658 	char *tname, *cp, *line = NULL;
659 	size_t linesize = 0;
660 	FILE *fp;
661 
662 	extern int optind;
663 	extern char *optarg;
664 
665 	TAILQ_INIT(&tq);
666 
667 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
668 	sanitise_stdfd();
669 
670 	if (argc <= 1)
671 		usage();
672 
673 	while ((opt = getopt(argc, argv, "cDHv46p:T:t:f:")) != -1) {
674 		switch (opt) {
675 		case 'H':
676 			hash_hosts = 1;
677 			break;
678 		case 'c':
679 			get_cert = 1;
680 			break;
681 		case 'D':
682 			print_sshfp = 1;
683 			break;
684 		case 'p':
685 			ssh_port = a2port(optarg);
686 			if (ssh_port <= 0) {
687 				fprintf(stderr, "Bad port '%s'\n", optarg);
688 				exit(1);
689 			}
690 			break;
691 		case 'T':
692 			timeout = convtime(optarg);
693 			if (timeout == -1 || timeout == 0) {
694 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
695 				usage();
696 			}
697 			break;
698 		case 'v':
699 			if (!debug_flag) {
700 				debug_flag = 1;
701 				log_level = SYSLOG_LEVEL_DEBUG1;
702 			}
703 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
704 				log_level++;
705 			else
706 				fatal("Too high debugging level.");
707 			break;
708 		case 'f':
709 			if (strcmp(optarg, "-") == 0)
710 				optarg = NULL;
711 			argv[fopt_count++] = optarg;
712 			break;
713 		case 't':
714 			get_keytypes = 0;
715 			tname = strtok(optarg, ",");
716 			while (tname) {
717 				int type = sshkey_type_from_name(tname);
718 
719 				switch (type) {
720 				case KEY_DSA:
721 					get_keytypes |= KT_DSA;
722 					break;
723 				case KEY_ECDSA:
724 					get_keytypes |= KT_ECDSA;
725 					break;
726 				case KEY_RSA:
727 					get_keytypes |= KT_RSA;
728 					break;
729 				case KEY_ED25519:
730 					get_keytypes |= KT_ED25519;
731 					break;
732 				case KEY_XMSS:
733 					get_keytypes |= KT_XMSS;
734 					break;
735 				case KEY_ED25519_SK:
736 					get_keytypes |= KT_ED25519_SK;
737 					break;
738 				case KEY_ECDSA_SK:
739 					get_keytypes |= KT_ECDSA_SK;
740 					break;
741 				case KEY_UNSPEC:
742 				default:
743 					fatal("Unknown key type \"%s\"", tname);
744 				}
745 				tname = strtok(NULL, ",");
746 			}
747 			break;
748 		case '4':
749 			IPv4or6 = AF_INET;
750 			break;
751 		case '6':
752 			IPv4or6 = AF_INET6;
753 			break;
754 		case '?':
755 		default:
756 			usage();
757 		}
758 	}
759 	if (optind == argc && !fopt_count)
760 		usage();
761 
762 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
763 
764 	maxfd = fdlim_get(1);
765 	if (maxfd < 0)
766 		fatal("%s: fdlim_get: bad value", __progname);
767 	if (maxfd > MAXMAXFD)
768 		maxfd = MAXMAXFD;
769 	if (MAXCON <= 0)
770 		fatal("%s: not enough file descriptors", __progname);
771 	if (maxfd > fdlim_get(0))
772 		fdlim_set(maxfd);
773 	fdcon = xcalloc(maxfd, sizeof(con));
774 
775 	read_wait_nfdset = howmany(maxfd, NFDBITS);
776 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
777 
778 	for (j = 0; j < fopt_count; j++) {
779 		if (argv[j] == NULL)
780 			fp = stdin;
781 		else if ((fp = fopen(argv[j], "r")) == NULL)
782 			fatal("%s: %s: %s", __progname, argv[j],
783 			    strerror(errno));
784 
785 		while (getline(&line, &linesize, fp) != -1) {
786 			/* Chomp off trailing whitespace and comments */
787 			if ((cp = strchr(line, '#')) == NULL)
788 				cp = line + strlen(line) - 1;
789 			while (cp >= line) {
790 				if (*cp == ' ' || *cp == '\t' ||
791 				    *cp == '\n' || *cp == '#')
792 					*cp-- = '\0';
793 				else
794 					break;
795 			}
796 
797 			/* Skip empty lines */
798 			if (*line == '\0')
799 				continue;
800 
801 			do_host(line);
802 		}
803 
804 		if (ferror(fp))
805 			fatal("%s: %s: %s", __progname, argv[j],
806 			    strerror(errno));
807 
808 		fclose(fp);
809 	}
810 	free(line);
811 
812 	while (optind < argc)
813 		do_host(argv[optind++]);
814 
815 	while (ncon > 0)
816 		conloop();
817 
818 	return found_one ? 0 : 1;
819 }
820