xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision a45db23f655e22f0c2354600d3b3c2cb98abf2dc) 
1 /*	$NetBSD: ssh-keyscan.c,v 1.31 2023/07/26 17:58:16 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.151 2023/02/10 06:41:53 jmc 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 1.31 2023/07/26 17:58:16 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 <poll.h>
31 #include <signal.h>
32 #include <string.h>
33 #include <unistd.h>
34 
35 #include "xmalloc.h"
36 #include "ssh.h"
37 #include "sshbuf.h"
38 #include "sshkey.h"
39 #include "cipher.h"
40 #include "digest.h"
41 #include "kex.h"
42 #include "compat.h"
43 #include "myproposal.h"
44 #include "packet.h"
45 #include "dispatch.h"
46 #include "log.h"
47 #include "atomicio.h"
48 #include "misc.h"
49 #include "hostfile.h"
50 #include "ssherr.h"
51 #include "ssh_api.h"
52 #include "dns.h"
53 #include "addr.h"
54 #include "fmt_scaled.h"
55 
56 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
57    Default value is AF_UNSPEC means both IPv4 and IPv6. */
58 int IPv4or6 = AF_UNSPEC;
59 
60 int ssh_port = SSH_DEFAULT_PORT;
61 
62 #define KT_DSA		(1)
63 #define KT_RSA		(1<<1)
64 #define KT_ECDSA	(1<<2)
65 #define KT_ED25519	(1<<3)
66 #define KT_XMSS		(1<<4)
67 #define KT_ECDSA_SK	(1<<5)
68 #define KT_ED25519_SK	(1<<6)
69 
70 #define KT_MIN		KT_DSA
71 #define KT_MAX		KT_ED25519_SK
72 
73 int get_cert = 0;
74 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
75 
76 int hash_hosts = 0;		/* Hash hostname on output */
77 
78 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
79 
80 int found_one = 0;		/* Successfully found a key */
81 
82 int hashalg = -1;		/* Hash for SSHFP records or -1 for all */
83 
84 #define MAXMAXFD 256
85 
86 /* The number of seconds after which to give up on a TCP connection */
87 int timeout = 5;
88 
89 int maxfd;
90 #define MAXCON (maxfd - 10)
91 
92 extern char *__progname;
93 struct pollfd *read_wait;
94 int ncon;
95 
96 /*
97  * Keep a connection structure for each file descriptor.  The state
98  * associated with file descriptor n is held in fdcon[n].
99  */
100 typedef struct Connection {
101 	u_char c_status;	/* State of connection on this file desc. */
102 #define CS_UNUSED 0		/* File descriptor unused */
103 #define CS_CON 1		/* Waiting to connect/read greeting */
104 #define CS_SIZE 2		/* Waiting to read initial packet size */
105 #define CS_KEYS 3		/* Waiting to read public key packet */
106 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
107 	int c_plen;		/* Packet length field for ssh packet */
108 	int c_len;		/* Total bytes which must be read. */
109 	int c_off;		/* Length of data read so far. */
110 	int c_keytype;		/* Only one of KT_* */
111 	sig_atomic_t c_done;	/* SSH2 done */
112 	char *c_namebase;	/* Address to free for c_name and c_namelist */
113 	char *c_name;		/* Hostname of connection for errors */
114 	char *c_namelist;	/* Pointer to other possible addresses */
115 	char *c_output_name;	/* Hostname of connection for output */
116 	char *c_data;		/* Data read from this fd */
117 	struct ssh *c_ssh;	/* SSH-connection */
118 	struct timespec c_ts;	/* Time at which connection gets aborted */
119 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
120 } con;
121 
122 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
123 con *fdcon;
124 
125 static void keyprint(con *c, struct sshkey *key);
126 
127 static int
128 fdlim_get(int hard)
129 {
130 	struct rlimit rlfd;
131 
132 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
133 		return (-1);
134 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
135 		return sysconf(_SC_OPEN_MAX);
136 	else
137 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
138 }
139 
140 static int
141 fdlim_set(int lim)
142 {
143 	struct rlimit rlfd;
144 
145 	if (lim <= 0)
146 		return (-1);
147 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
148 		return (-1);
149 	rlfd.rlim_cur = lim;
150 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
151 		return (-1);
152 	return (0);
153 }
154 
155 /*
156  * This is an strsep function that returns a null field for adjacent
157  * separators.  This is the same as the 4.4BSD strsep, but different from the
158  * one in the GNU libc.
159  */
160 static char *
161 xstrsep(char **str, const char *delim)
162 {
163 	char *s, *e;
164 
165 	if (!**str)
166 		return (NULL);
167 
168 	s = *str;
169 	e = s + strcspn(s, delim);
170 
171 	if (*e != '\0')
172 		*e++ = '\0';
173 	*str = e;
174 
175 	return (s);
176 }
177 
178 /*
179  * Get the next non-null token (like GNU strsep).  Strsep() will return a
180  * null token for two adjacent separators, so we may have to loop.
181  */
182 static char *
183 strnnsep(char **stringp, const char *delim)
184 {
185 	char *tok;
186 
187 	do {
188 		tok = xstrsep(stringp, delim);
189 	} while (tok && *tok == '\0');
190 	return (tok);
191 }
192 
193 
194 static int
195 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
196 {
197 	con *c;
198 
199 	if ((c = ssh_get_app_data(ssh)) != NULL)
200 		keyprint(c, hostkey);
201 	/* always abort key exchange */
202 	return -1;
203 }
204 
205 static int
206 ssh2_capable(int remote_major, int remote_minor)
207 {
208 	switch (remote_major) {
209 	case 1:
210 		if (remote_minor == 99)
211 			return 1;
212 		break;
213 	case 2:
214 		return 1;
215 	default:
216 		break;
217 	}
218 	return 0;
219 }
220 
221 static void
222 keygrab_ssh2(con *c)
223 {
224 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
225 	int r;
226 
227 	switch (c->c_keytype) {
228 	case KT_DSA:
229 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
230 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
231 		break;
232 	case KT_RSA:
233 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
234 		    "rsa-sha2-512-cert-v01@openssh.com,"
235 		    "rsa-sha2-256-cert-v01@openssh.com,"
236 		    "ssh-rsa-cert-v01@openssh.com" :
237 		    "rsa-sha2-512,"
238 		    "rsa-sha2-256,"
239 		    "ssh-rsa";
240 		break;
241 	case KT_ED25519:
242 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
243 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
244 		break;
245 	case KT_XMSS:
246 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
247 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
248 		break;
249 	case KT_ECDSA:
250 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
251 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
252 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
253 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
254 		    "ecdsa-sha2-nistp256,"
255 		    "ecdsa-sha2-nistp384,"
256 		    "ecdsa-sha2-nistp521";
257 		break;
258 	case KT_ECDSA_SK:
259 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
260 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
261 		    "sk-ecdsa-sha2-nistp256@openssh.com";
262 		break;
263 	case KT_ED25519_SK:
264 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
265 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
266 		    "sk-ssh-ed25519@openssh.com";
267 		break;
268 	default:
269 		fatal("unknown key type %d", c->c_keytype);
270 		break;
271 	}
272 	if ((r = kex_setup(c->c_ssh, __UNCONST(myproposal))) != 0) {
273 		free(c->c_ssh);
274 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
275 		exit(1);
276 	}
277 #ifdef WITH_OPENSSL
278 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
279 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
280 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
281 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
282 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
283 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
284 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
285 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
286 #endif
287 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
288 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
289 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
290 	/*
291 	 * do the key-exchange until an error occurs or until
292 	 * the key_print_wrapper() callback sets c_done.
293 	 */
294 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
295 }
296 
297 static void
298 keyprint_one(const char *host, struct sshkey *key)
299 {
300 	char *hostport = NULL, *hashed = NULL;
301 	const char *known_host;
302 
303 	found_one = 1;
304 
305 	if (print_sshfp) {
306 		export_dns_rr(host, key, stdout, 0, hashalg);
307 		return;
308 	}
309 
310 	hostport = put_host_port(host, ssh_port);
311 	lowercase(hostport);
312 	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
313 		fatal("host_hash failed");
314 	known_host = hash_hosts ? hashed : hostport;
315 	if (!get_cert)
316 		fprintf(stdout, "%s ", known_host);
317 	sshkey_write(key, stdout);
318 	fputs("\n", stdout);
319 	free(hashed);
320 	free(hostport);
321 }
322 
323 static void
324 keyprint(con *c, struct sshkey *key)
325 {
326 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
327 	char *host, *ohosts;
328 
329 	if (key == NULL)
330 		return;
331 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
332 		keyprint_one(hosts, key);
333 		return;
334 	}
335 	ohosts = hosts = xstrdup(hosts);
336 	while ((host = strsep(&hosts, ",")) != NULL)
337 		keyprint_one(host, key);
338 	free(ohosts);
339 }
340 
341 static int
342 tcpconnect(char *host)
343 {
344 	struct addrinfo hints, *ai, *aitop;
345 	char strport[NI_MAXSERV];
346 	int gaierr, s = -1;
347 
348 	snprintf(strport, sizeof strport, "%d", ssh_port);
349 	memset(&hints, 0, sizeof(hints));
350 	hints.ai_family = IPv4or6;
351 	hints.ai_socktype = SOCK_STREAM;
352 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
353 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
354 		return -1;
355 	}
356 	for (ai = aitop; ai; ai = ai->ai_next) {
357 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
358 		if (s == -1) {
359 			error("socket: %s", strerror(errno));
360 			continue;
361 		}
362 		if (set_nonblock(s) == -1)
363 			fatal_f("set_nonblock(%d)", s);
364 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
365 		    errno != EINPROGRESS)
366 			error("connect (`%s'): %s", host, strerror(errno));
367 		else
368 			break;
369 		close(s);
370 		s = -1;
371 	}
372 	freeaddrinfo(aitop);
373 	return s;
374 }
375 
376 static int
377 conalloc(const char *iname, const char *oname, int keytype)
378 {
379 	char *namebase, *name, *namelist;
380 	int s;
381 
382 	namebase = namelist = xstrdup(iname);
383 
384 	do {
385 		name = xstrsep(&namelist, ",");
386 		if (!name) {
387 			free(namebase);
388 			return (-1);
389 		}
390 	} while ((s = tcpconnect(name)) < 0);
391 
392 	if (s >= maxfd)
393 		fatal("conalloc: fdno %d too high", s);
394 	if (fdcon[s].c_status)
395 		fatal("conalloc: attempt to reuse fdno %d", s);
396 
397 	debug3_f("oname %s kt %d", oname, keytype);
398 	fdcon[s].c_fd = s;
399 	fdcon[s].c_status = CS_CON;
400 	fdcon[s].c_namebase = namebase;
401 	fdcon[s].c_name = name;
402 	fdcon[s].c_namelist = namelist;
403 	fdcon[s].c_output_name = xstrdup(oname);
404 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
405 	fdcon[s].c_len = 4;
406 	fdcon[s].c_off = 0;
407 	fdcon[s].c_keytype = keytype;
408 	monotime_ts(&fdcon[s].c_ts);
409 	fdcon[s].c_ts.tv_sec += timeout;
410 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
411 	read_wait[s].fd = s;
412 	read_wait[s].events = POLLIN;
413 	ncon++;
414 	return (s);
415 }
416 
417 static void
418 confree(int s)
419 {
420 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
421 		fatal("confree: attempt to free bad fdno %d", s);
422 	free(fdcon[s].c_namebase);
423 	free(fdcon[s].c_output_name);
424 	if (fdcon[s].c_status == CS_KEYS)
425 		free(fdcon[s].c_data);
426 	fdcon[s].c_status = CS_UNUSED;
427 	fdcon[s].c_keytype = 0;
428 	if (fdcon[s].c_ssh) {
429 		ssh_packet_close(fdcon[s].c_ssh);
430 		free(fdcon[s].c_ssh);
431 		fdcon[s].c_ssh = NULL;
432 	} else
433 		close(s);
434 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
435 	read_wait[s].fd = -1;
436 	read_wait[s].events = 0;
437 	ncon--;
438 }
439 
440 static void
441 contouch(int s)
442 {
443 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
444 	monotime_ts(&fdcon[s].c_ts);
445 	fdcon[s].c_ts.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 	/* send client banner */
470 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
471 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
472 	if (n < 0 || (size_t)n >= sizeof(buf)) {
473 		error("snprintf: buffer too small");
474 		confree(s);
475 		return;
476 	}
477 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
478 		error("write (%s): %s", c->c_name, strerror(errno));
479 		confree(s);
480 		return;
481 	}
482 
483 	/*
484 	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
485 	 * protocol identification string may be preceeded by an arbitrarily
486 	 * large banner which we must read and ignore.  Loop while reading
487 	 * newline-terminated lines until we have one starting with "SSH-".
488 	 * The ID string cannot be longer than 255 characters although the
489 	 * preceeding banner lines may (in which case they'll be discarded
490 	 * in multiple iterations of the outer loop).
491 	 */
492 	for (;;) {
493 		memset(buf, '\0', sizeof(buf));
494 		bufsiz = sizeof(buf);
495 		cp = buf;
496 		while (bufsiz-- &&
497 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
498 			if (*cp == '\r')
499 				*cp = '\n';
500 			cp++;
501 		}
502 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
503 			break;
504 	}
505 	if (n == 0) {
506 		switch (errno) {
507 		case EPIPE:
508 			error("%s: Connection closed by remote host", c->c_name);
509 			break;
510 		case ECONNREFUSED:
511 			break;
512 		default:
513 			error("read (%s): %s", c->c_name, strerror(errno));
514 			break;
515 		}
516 		conrecycle(s);
517 		return;
518 	}
519 	if (cp >= buf + sizeof(buf)) {
520 		error("%s: greeting exceeds allowable length", c->c_name);
521 		confree(s);
522 		return;
523 	}
524 	if (*cp != '\n' && *cp != '\r') {
525 		error("%s: bad greeting", c->c_name);
526 		confree(s);
527 		return;
528 	}
529 	*cp = '\0';
530 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
531 		fatal("ssh_packet_set_connection failed");
532 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
533 	ssh_set_app_data(c->c_ssh, c);	/* back link */
534 	c->c_ssh->compat = 0;
535 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
536 	    &remote_major, &remote_minor, remote_version) == 3)
537 		compat_banner(c->c_ssh, remote_version);
538 	if (!ssh2_capable(remote_major, remote_minor)) {
539 		debug("%s doesn't support ssh2", c->c_name);
540 		confree(s);
541 		return;
542 	}
543 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
544 	    c->c_name, ssh_port, chop(buf));
545 	keygrab_ssh2(c);
546 	confree(s);
547 }
548 
549 static void
550 conread(int s)
551 {
552 	con *c = &fdcon[s];
553 	size_t n;
554 
555 	if (c->c_status == CS_CON) {
556 		congreet(s);
557 		return;
558 	}
559 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
560 	if (n == 0) {
561 		error("read (%s): %s", c->c_name, strerror(errno));
562 		confree(s);
563 		return;
564 	}
565 	c->c_off += n;
566 
567 	if (c->c_off == c->c_len)
568 		switch (c->c_status) {
569 		case CS_SIZE:
570 			c->c_plen = htonl(c->c_plen);
571 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
572 			c->c_off = 0;
573 			c->c_data = xmalloc(c->c_len);
574 			c->c_status = CS_KEYS;
575 			break;
576 		default:
577 			fatal("conread: invalid status %d", c->c_status);
578 			break;
579 		}
580 
581 	contouch(s);
582 }
583 
584 static void
585 conloop(void)
586 {
587 	struct timespec seltime, now;
588 	con *c;
589 	int i;
590 
591 	monotime_ts(&now);
592 	c = TAILQ_FIRST(&tq);
593 
594 	if (c && timespeccmp(&c->c_ts, &now, >))
595 		timespecsub(&c->c_ts, &now, &seltime);
596 	else
597 		timespecclear(&seltime);
598 
599 	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
600 		if (errno == EAGAIN || errno == EINTR)
601 			continue;
602 		error("poll error");
603 	}
604 
605 	for (i = 0; i < maxfd; i++) {
606 		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
607 			confree(i);
608 		else if (read_wait[i].revents & (POLLIN|POLLHUP))
609 			conread(i);
610 	}
611 
612 	c = TAILQ_FIRST(&tq);
613 	while (c && timespeccmp(&c->c_ts, &now, <)) {
614 		int s = c->c_fd;
615 
616 		c = TAILQ_NEXT(c, c_link);
617 		conrecycle(s);
618 	}
619 }
620 
621 static void
622 do_one_host(char *host)
623 {
624 	char *name = strnnsep(&host, " \t\n");
625 	int j;
626 
627 	if (name == NULL)
628 		return;
629 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
630 		if (get_keytypes & j) {
631 			while (ncon >= MAXCON)
632 				conloop();
633 			conalloc(name, *host ? host : name, j);
634 		}
635 	}
636 }
637 
638 static void
639 do_host(char *host)
640 {
641 	char daddr[128];
642 	struct xaddr addr, end_addr;
643 	u_int masklen;
644 
645 	if (host == NULL)
646 		return;
647 	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
648 		/* Assume argument is a hostname */
649 		do_one_host(host);
650 	} else {
651 		/* Argument is a CIDR range */
652 		debug("CIDR range %s", host);
653 		end_addr = addr;
654 		if (addr_host_to_all1s(&end_addr, masklen) != 0)
655 			goto badaddr;
656 		/*
657 		 * Note: we deliberately include the all-zero/ones addresses.
658 		 */
659 		for (;;) {
660 			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
661  badaddr:
662 				error("Invalid address %s", host);
663 				return;
664 			}
665 			debug("CIDR expand: address %s", daddr);
666 			do_one_host(daddr);
667 			if (addr_cmp(&addr, &end_addr) == 0)
668 				break;
669 			addr_increment(&addr);
670 		};
671 	}
672 }
673 
674 void
675 sshfatal(const char *file, const char *func, int line, int showfunc,
676     LogLevel level, const char *suffix, const char *fmt, ...)
677 {
678 	va_list args;
679 
680 	va_start(args, fmt);
681 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
682 	va_end(args);
683 	cleanup_exit(255);
684 }
685 
686 __dead static void
687 usage(void)
688 {
689 	fprintf(stderr,
690 	    "usage: ssh-keyscan [-46cDHv] [-f file] [-O option] [-p port] [-T timeout]\n"
691 	    "                   [-t type] [host | addrlist namelist]\n");
692 	exit(1);
693 }
694 
695 int
696 main(int argc, char **argv)
697 {
698 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
699 	int opt, fopt_count = 0, j;
700 	char *tname, *cp, *line = NULL;
701 	size_t linesize = 0;
702 	FILE *fp;
703 
704 	extern int optind;
705 	extern char *optarg;
706 
707 	TAILQ_INIT(&tq);
708 
709 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
710 	sanitise_stdfd();
711 
712 	if (argc <= 1)
713 		usage();
714 
715 	while ((opt = getopt(argc, argv, "cDHv46O:p:T:t:f:")) != -1) {
716 		switch (opt) {
717 		case 'H':
718 			hash_hosts = 1;
719 			break;
720 		case 'c':
721 			get_cert = 1;
722 			break;
723 		case 'D':
724 			print_sshfp = 1;
725 			break;
726 		case 'p':
727 			ssh_port = a2port(optarg);
728 			if (ssh_port <= 0) {
729 				fprintf(stderr, "Bad port '%s'\n", optarg);
730 				exit(1);
731 			}
732 			break;
733 		case 'T':
734 			timeout = convtime(optarg);
735 			if (timeout == -1 || timeout == 0) {
736 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
737 				usage();
738 			}
739 			break;
740 		case 'v':
741 			if (!debug_flag) {
742 				debug_flag = 1;
743 				log_level = SYSLOG_LEVEL_DEBUG1;
744 			}
745 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
746 				log_level++;
747 			else
748 				fatal("Too high debugging level.");
749 			break;
750 		case 'f':
751 			if (strcmp(optarg, "-") == 0)
752 				optarg = NULL;
753 			argv[fopt_count++] = optarg;
754 			break;
755 		case 'O':
756 			/* Maybe other misc options in the future too */
757 			if (strncmp(optarg, "hashalg=", 8) != 0)
758 				fatal("Unsupported -O option");
759 			if ((hashalg = ssh_digest_alg_by_name(
760 			    optarg + 8)) == -1)
761 				fatal("Unsupported hash algorithm");
762 			break;
763 		case 't':
764 			get_keytypes = 0;
765 			tname = strtok(optarg, ",");
766 			while (tname) {
767 				int type = sshkey_type_from_name(tname);
768 
769 				switch (type) {
770 				case KEY_DSA:
771 					get_keytypes |= KT_DSA;
772 					break;
773 				case KEY_ECDSA:
774 					get_keytypes |= KT_ECDSA;
775 					break;
776 				case KEY_RSA:
777 					get_keytypes |= KT_RSA;
778 					break;
779 				case KEY_ED25519:
780 					get_keytypes |= KT_ED25519;
781 					break;
782 				case KEY_XMSS:
783 					get_keytypes |= KT_XMSS;
784 					break;
785 				case KEY_ED25519_SK:
786 					get_keytypes |= KT_ED25519_SK;
787 					break;
788 				case KEY_ECDSA_SK:
789 					get_keytypes |= KT_ECDSA_SK;
790 					break;
791 				case KEY_UNSPEC:
792 				default:
793 					fatal("Unknown key type \"%s\"", tname);
794 				}
795 				tname = strtok(NULL, ",");
796 			}
797 			break;
798 		case '4':
799 			IPv4or6 = AF_INET;
800 			break;
801 		case '6':
802 			IPv4or6 = AF_INET6;
803 			break;
804 		default:
805 			usage();
806 		}
807 	}
808 	if (optind == argc && !fopt_count)
809 		usage();
810 
811 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
812 
813 	maxfd = fdlim_get(1);
814 	if (maxfd < 0)
815 		fatal("%s: fdlim_get: bad value", __progname);
816 	if (maxfd > MAXMAXFD)
817 		maxfd = MAXMAXFD;
818 	if (MAXCON <= 0)
819 		fatal("%s: not enough file descriptors", __progname);
820 	if (maxfd > fdlim_get(0))
821 		fdlim_set(maxfd);
822 	fdcon = xcalloc(maxfd, sizeof(con));
823 	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
824 	for (j = 0; j < maxfd; j++)
825 		read_wait[j].fd = -1;
826 
827 	for (j = 0; j < fopt_count; j++) {
828 		if (argv[j] == NULL)
829 			fp = stdin;
830 		else if ((fp = fopen(argv[j], "r")) == NULL)
831 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
832 
833 		while (getline(&line, &linesize, fp) != -1) {
834 			/* Chomp off trailing whitespace and comments */
835 			if ((cp = strchr(line, '#')) == NULL)
836 				cp = line + strlen(line) - 1;
837 			while (cp >= line) {
838 				if (*cp == ' ' || *cp == '\t' ||
839 				    *cp == '\n' || *cp == '#')
840 					*cp-- = '\0';
841 				else
842 					break;
843 			}
844 
845 			/* Skip empty lines */
846 			if (*line == '\0')
847 				continue;
848 
849 			do_host(line);
850 		}
851 
852 		if (ferror(fp))
853 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
854 
855 		fclose(fp);
856 	}
857 	free(line);
858 
859 	while (optind < argc)
860 		do_host(argv[optind++]);
861 
862 	while (ncon > 0)
863 		conloop();
864 
865 	return found_one ? 0 : 1;
866 }
867