xref: /openbsd-src/usr.bin/ssh/ssh-keyscan.c (revision 5c389b79544373bccfce668b646e62e7ba9802a3) 
1 /* $OpenBSD: ssh-keyscan.c,v 1.153 2023/06/21 05:06:04 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 #ifdef WITH_OPENSSL
17 #include <openssl/bn.h>
18 #endif
19 
20 #include <errno.h>
21 #include <limits.h>
22 #include <netdb.h>
23 #include <stdarg.h>
24 #include <stdio.h>
25 #include <stdlib.h>
26 #include <poll.h>
27 #include <signal.h>
28 #include <string.h>
29 #include <unistd.h>
30 
31 #include "xmalloc.h"
32 #include "ssh.h"
33 #include "sshbuf.h"
34 #include "sshkey.h"
35 #include "cipher.h"
36 #include "digest.h"
37 #include "kex.h"
38 #include "compat.h"
39 #include "myproposal.h"
40 #include "packet.h"
41 #include "dispatch.h"
42 #include "log.h"
43 #include "atomicio.h"
44 #include "misc.h"
45 #include "hostfile.h"
46 #include "ssherr.h"
47 #include "ssh_api.h"
48 #include "dns.h"
49 #include "addr.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_DSA		(1)
58 #define KT_RSA		(1<<1)
59 #define KT_ECDSA	(1<<2)
60 #define KT_ED25519	(1<<3)
61 #define KT_XMSS		(1<<4)
62 #define KT_ECDSA_SK	(1<<5)
63 #define KT_ED25519_SK	(1<<6)
64 
65 #define KT_MIN		KT_DSA
66 #define KT_MAX		KT_ED25519_SK
67 
68 int get_cert = 0;
69 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
70 
71 int hash_hosts = 0;		/* Hash hostname on output */
72 
73 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
74 
75 int found_one = 0;		/* Successfully found a key */
76 
77 int hashalg = -1;		/* Hash for SSHFP records or -1 for all */
78 
79 #define MAXMAXFD 256
80 
81 /* The number of seconds after which to give up on a TCP connection */
82 int timeout = 5;
83 
84 int maxfd;
85 #define MAXCON (maxfd - 10)
86 
87 extern char *__progname;
88 struct pollfd *read_wait;
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 timespec c_ts;	/* 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 	    (hard ? rlfd.rlim_max : rlfd.rlim_cur) > INT_MAX)
131 		return sysconf(_SC_OPEN_MAX);
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, 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 	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_SNTRUP761X25519_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 = NULL, *hashed = NULL;
296 	const char *known_host;
297 	int r = 0;
298 
299 	found_one = 1;
300 
301 	if (print_sshfp) {
302 		export_dns_rr(host, key, stdout, 0, hashalg);
303 		return;
304 	}
305 
306 	hostport = put_host_port(host, ssh_port);
307 	lowercase(hostport);
308 	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
309 		fatal("host_hash failed");
310 	known_host = hash_hosts ? hashed : hostport;
311 	if (!get_cert)
312 		r = fprintf(stdout, "%s ", known_host);
313 	if (r >= 0 && sshkey_write(key, stdout) == 0)
314 		(void)fputs("\n", stdout);
315 	free(hashed);
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 == -1) {
355 			error("socket: %s", strerror(errno));
356 			continue;
357 		}
358 		if (set_nonblock(s) == -1)
359 			fatal_f("set_nonblock(%d)", s);
360 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
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(const char *iname, const 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_f("oname %s kt %d", 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 	monotime_ts(&fdcon[s].c_ts);
405 	fdcon[s].c_ts.tv_sec += timeout;
406 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
407 	read_wait[s].fd = s;
408 	read_wait[s].events = POLLIN;
409 	ncon++;
410 	return (s);
411 }
412 
413 static void
414 confree(int s)
415 {
416 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
417 		fatal("confree: attempt to free bad fdno %d", 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 	} else
429 		close(s);
430 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
431 	read_wait[s].fd = -1;
432 	read_wait[s].events = 0;
433 	ncon--;
434 }
435 
436 static void
437 contouch(int s)
438 {
439 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
440 	monotime_ts(&fdcon[s].c_ts);
441 	fdcon[s].c_ts.tv_sec += timeout;
442 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
443 }
444 
445 static int
446 conrecycle(int s)
447 {
448 	con *c = &fdcon[s];
449 	int ret;
450 
451 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
452 	confree(s);
453 	return (ret);
454 }
455 
456 static void
457 congreet(int s)
458 {
459 	int n = 0, remote_major = 0, remote_minor = 0;
460 	char buf[256], *cp;
461 	char remote_version[sizeof buf];
462 	size_t bufsiz;
463 	con *c = &fdcon[s];
464 
465 	/* send client banner */
466 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
467 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
468 	if (n < 0 || (size_t)n >= sizeof(buf)) {
469 		error("snprintf: buffer too small");
470 		confree(s);
471 		return;
472 	}
473 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
474 		error("write (%s): %s", c->c_name, strerror(errno));
475 		confree(s);
476 		return;
477 	}
478 
479 	/*
480 	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
481 	 * protocol identification string may be preceeded by an arbitrarily
482 	 * large banner which we must read and ignore.  Loop while reading
483 	 * newline-terminated lines until we have one starting with "SSH-".
484 	 * The ID string cannot be longer than 255 characters although the
485 	 * preceeding banner lines may (in which case they'll be discarded
486 	 * in multiple iterations of the outer loop).
487 	 */
488 	for (;;) {
489 		memset(buf, '\0', sizeof(buf));
490 		bufsiz = sizeof(buf);
491 		cp = buf;
492 		while (bufsiz-- &&
493 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
494 			if (*cp == '\r')
495 				*cp = '\n';
496 			cp++;
497 		}
498 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
499 			break;
500 	}
501 	if (n == 0) {
502 		switch (errno) {
503 		case EPIPE:
504 			error("%s: Connection closed by remote host", c->c_name);
505 			break;
506 		case ECONNREFUSED:
507 			break;
508 		default:
509 			error("read (%s): %s", c->c_name, strerror(errno));
510 			break;
511 		}
512 		conrecycle(s);
513 		return;
514 	}
515 	if (cp >= buf + sizeof(buf)) {
516 		error("%s: greeting exceeds allowable length", c->c_name);
517 		confree(s);
518 		return;
519 	}
520 	if (*cp != '\n' && *cp != '\r') {
521 		error("%s: bad greeting", c->c_name);
522 		confree(s);
523 		return;
524 	}
525 	*cp = '\0';
526 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
527 		fatal("ssh_packet_set_connection failed");
528 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
529 	ssh_set_app_data(c->c_ssh, c);	/* back link */
530 	c->c_ssh->compat = 0;
531 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
532 	    &remote_major, &remote_minor, remote_version) == 3)
533 		compat_banner(c->c_ssh, remote_version);
534 	if (!ssh2_capable(remote_major, remote_minor)) {
535 		debug("%s doesn't support ssh2", c->c_name);
536 		confree(s);
537 		return;
538 	}
539 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
540 	    c->c_name, ssh_port, chop(buf));
541 	keygrab_ssh2(c);
542 	confree(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 		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 timespec seltime, now;
584 	con *c;
585 	int i;
586 
587 	monotime_ts(&now);
588 	c = TAILQ_FIRST(&tq);
589 
590 	if (c && timespeccmp(&c->c_ts, &now, >))
591 		timespecsub(&c->c_ts, &now, &seltime);
592 	else
593 		timespecclear(&seltime);
594 
595 	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
596 		if (errno == EAGAIN || errno == EINTR)
597 			continue;
598 		error("poll error");
599 	}
600 
601 	for (i = 0; i < maxfd; i++) {
602 		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
603 			confree(i);
604 		else if (read_wait[i].revents & (POLLIN|POLLHUP))
605 			conread(i);
606 	}
607 
608 	c = TAILQ_FIRST(&tq);
609 	while (c && timespeccmp(&c->c_ts, &now, <)) {
610 		int s = c->c_fd;
611 
612 		c = TAILQ_NEXT(c, c_link);
613 		conrecycle(s);
614 	}
615 }
616 
617 static void
618 do_one_host(char *host)
619 {
620 	char *name = strnnsep(&host, " \t\n");
621 	int j;
622 
623 	if (name == NULL)
624 		return;
625 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
626 		if (get_keytypes & j) {
627 			while (ncon >= MAXCON)
628 				conloop();
629 			conalloc(name, *host ? host : name, j);
630 		}
631 	}
632 }
633 
634 static void
635 do_host(char *host)
636 {
637 	char daddr[128];
638 	struct xaddr addr, end_addr;
639 	u_int masklen;
640 
641 	if (host == NULL)
642 		return;
643 	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
644 		/* Assume argument is a hostname */
645 		do_one_host(host);
646 	} else {
647 		/* Argument is a CIDR range */
648 		debug("CIDR range %s", host);
649 		end_addr = addr;
650 		if (addr_host_to_all1s(&end_addr, masklen) != 0)
651 			goto badaddr;
652 		/*
653 		 * Note: we deliberately include the all-zero/ones addresses.
654 		 */
655 		for (;;) {
656 			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
657  badaddr:
658 				error("Invalid address %s", host);
659 				return;
660 			}
661 			debug("CIDR expand: address %s", daddr);
662 			do_one_host(daddr);
663 			if (addr_cmp(&addr, &end_addr) == 0)
664 				break;
665 			addr_increment(&addr);
666 		};
667 	}
668 }
669 
670 void
671 sshfatal(const char *file, const char *func, int line, int showfunc,
672     LogLevel level, const char *suffix, const char *fmt, ...)
673 {
674 	va_list args;
675 
676 	va_start(args, fmt);
677 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
678 	va_end(args);
679 	cleanup_exit(255);
680 }
681 
682 static void
683 usage(void)
684 {
685 	fprintf(stderr,
686 	    "usage: ssh-keyscan [-46cDHv] [-f file] [-O option] [-p port] [-T timeout]\n"
687 	    "                   [-t type] [host | addrlist namelist]\n");
688 	exit(1);
689 }
690 
691 int
692 main(int argc, char **argv)
693 {
694 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
695 	int opt, fopt_count = 0, j;
696 	char *tname, *cp, *line = NULL;
697 	size_t linesize = 0;
698 	FILE *fp;
699 
700 	extern int optind;
701 	extern char *optarg;
702 
703 	TAILQ_INIT(&tq);
704 
705 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
706 	sanitise_stdfd();
707 
708 	if (argc <= 1)
709 		usage();
710 
711 	while ((opt = getopt(argc, argv, "cDHv46O:p:T:t:f:")) != -1) {
712 		switch (opt) {
713 		case 'H':
714 			hash_hosts = 1;
715 			break;
716 		case 'c':
717 			get_cert = 1;
718 			break;
719 		case 'D':
720 			print_sshfp = 1;
721 			break;
722 		case 'p':
723 			ssh_port = a2port(optarg);
724 			if (ssh_port <= 0) {
725 				fprintf(stderr, "Bad port '%s'\n", optarg);
726 				exit(1);
727 			}
728 			break;
729 		case 'T':
730 			timeout = convtime(optarg);
731 			if (timeout == -1 || timeout == 0) {
732 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
733 				usage();
734 			}
735 			break;
736 		case 'v':
737 			if (!debug_flag) {
738 				debug_flag = 1;
739 				log_level = SYSLOG_LEVEL_DEBUG1;
740 			}
741 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
742 				log_level++;
743 			else
744 				fatal("Too high debugging level.");
745 			break;
746 		case 'f':
747 			if (strcmp(optarg, "-") == 0)
748 				optarg = NULL;
749 			argv[fopt_count++] = optarg;
750 			break;
751 		case 'O':
752 			/* Maybe other misc options in the future too */
753 			if (strncmp(optarg, "hashalg=", 8) != 0)
754 				fatal("Unsupported -O option");
755 			if ((hashalg = ssh_digest_alg_by_name(
756 			    optarg + 8)) == -1)
757 				fatal("Unsupported hash algorithm");
758 			break;
759 		case 't':
760 			get_keytypes = 0;
761 			tname = strtok(optarg, ",");
762 			while (tname) {
763 				int type = sshkey_type_from_name(tname);
764 
765 				switch (type) {
766 				case KEY_DSA:
767 					get_keytypes |= KT_DSA;
768 					break;
769 				case KEY_ECDSA:
770 					get_keytypes |= KT_ECDSA;
771 					break;
772 				case KEY_RSA:
773 					get_keytypes |= KT_RSA;
774 					break;
775 				case KEY_ED25519:
776 					get_keytypes |= KT_ED25519;
777 					break;
778 				case KEY_XMSS:
779 					get_keytypes |= KT_XMSS;
780 					break;
781 				case KEY_ED25519_SK:
782 					get_keytypes |= KT_ED25519_SK;
783 					break;
784 				case KEY_ECDSA_SK:
785 					get_keytypes |= KT_ECDSA_SK;
786 					break;
787 				case KEY_UNSPEC:
788 				default:
789 					fatal("Unknown key type \"%s\"", tname);
790 				}
791 				tname = strtok(NULL, ",");
792 			}
793 			break;
794 		case '4':
795 			IPv4or6 = AF_INET;
796 			break;
797 		case '6':
798 			IPv4or6 = AF_INET6;
799 			break;
800 		default:
801 			usage();
802 		}
803 	}
804 	if (optind == argc && !fopt_count)
805 		usage();
806 
807 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
808 
809 	maxfd = fdlim_get(1);
810 	if (maxfd < 0)
811 		fatal("%s: fdlim_get: bad value", __progname);
812 	if (maxfd > MAXMAXFD)
813 		maxfd = MAXMAXFD;
814 	if (MAXCON <= 0)
815 		fatal("%s: not enough file descriptors", __progname);
816 	if (maxfd > fdlim_get(0))
817 		fdlim_set(maxfd);
818 	fdcon = xcalloc(maxfd, sizeof(con));
819 	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
820 	for (j = 0; j < maxfd; j++)
821 		read_wait[j].fd = -1;
822 
823 	for (j = 0; j < fopt_count; j++) {
824 		if (argv[j] == NULL)
825 			fp = stdin;
826 		else if ((fp = fopen(argv[j], "r")) == NULL)
827 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
828 
829 		while (getline(&line, &linesize, fp) != -1) {
830 			/* Chomp off trailing whitespace and comments */
831 			if ((cp = strchr(line, '#')) == NULL)
832 				cp = line + strlen(line) - 1;
833 			while (cp >= line) {
834 				if (*cp == ' ' || *cp == '\t' ||
835 				    *cp == '\n' || *cp == '#')
836 					*cp-- = '\0';
837 				else
838 					break;
839 			}
840 
841 			/* Skip empty lines */
842 			if (*line == '\0')
843 				continue;
844 
845 			do_host(line);
846 		}
847 
848 		if (ferror(fp))
849 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
850 
851 		fclose(fp);
852 	}
853 	free(line);
854 
855 	while (optind < argc)
856 		do_host(argv[optind++]);
857 
858 	while (ncon > 0)
859 		conloop();
860 
861 	return found_one ? 0 : 1;
862 }
863