xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision c42dbd0ed2e61fe6eda8590caa852ccf34719964) 
1 /*	$NetBSD: ssh-keyscan.c,v 1.33 2024/06/25 16:36:54 christos Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.155 2024/01/11 01:45:36 djm 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 1.33 2024/06/25 16:36:54 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 #ifdef WITH_OPENSSL
23 #include <openssl/bn.h>
24 #endif
25 
26 #include <errno.h>
27 #include <limits.h>
28 #include <netdb.h>
29 #include <stdarg.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <poll.h>
33 #include <signal.h>
34 #include <string.h>
35 #include <unistd.h>
36 
37 #include "xmalloc.h"
38 #include "ssh.h"
39 #include "sshbuf.h"
40 #include "sshkey.h"
41 #include "cipher.h"
42 #include "digest.h"
43 #include "kex.h"
44 #include "compat.h"
45 #include "myproposal.h"
46 #include "packet.h"
47 #include "dispatch.h"
48 #include "log.h"
49 #include "atomicio.h"
50 #include "misc.h"
51 #include "hostfile.h"
52 #include "ssherr.h"
53 #include "ssh_api.h"
54 #include "dns.h"
55 #include "addr.h"
56 #include "fmt_scaled.h"
57 
58 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
59    Default value is AF_UNSPEC means both IPv4 and IPv6. */
60 int IPv4or6 = AF_UNSPEC;
61 
62 int ssh_port = SSH_DEFAULT_PORT;
63 
64 #define KT_DSA		(1)
65 #define KT_RSA		(1<<1)
66 #define KT_ECDSA	(1<<2)
67 #define KT_ED25519	(1<<3)
68 #define KT_XMSS		(1<<4)
69 #define KT_ECDSA_SK	(1<<5)
70 #define KT_ED25519_SK	(1<<6)
71 
72 #define KT_MIN		KT_DSA
73 #define KT_MAX		KT_ED25519_SK
74 
75 int get_cert = 0;
76 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
77 
78 int hash_hosts = 0;		/* Hash hostname on output */
79 
80 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
81 
82 int found_one = 0;		/* Successfully found a key */
83 
84 int hashalg = -1;		/* Hash for SSHFP records or -1 for all */
85 
86 #define MAXMAXFD 256
87 
88 /* The number of seconds after which to give up on a TCP connection */
89 int timeout = 5;
90 
91 int maxfd;
92 #define MAXCON (maxfd - 10)
93 
94 extern char *__progname;
95 struct pollfd *read_wait;
96 int ncon;
97 
98 /*
99  * Keep a connection structure for each file descriptor.  The state
100  * associated with file descriptor n is held in fdcon[n].
101  */
102 typedef struct Connection {
103 	u_char c_status;	/* State of connection on this file desc. */
104 #define CS_UNUSED 0		/* File descriptor unused */
105 #define CS_CON 1		/* Waiting to connect/read greeting */
106 #define CS_SIZE 2		/* Waiting to read initial packet size */
107 #define CS_KEYS 3		/* Waiting to read public key packet */
108 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
109 	int c_plen;		/* Packet length field for ssh packet */
110 	int c_len;		/* Total bytes which must be read. */
111 	int c_off;		/* Length of data read so far. */
112 	int c_keytype;		/* Only one of KT_* */
113 	sig_atomic_t c_done;	/* SSH2 done */
114 	char *c_namebase;	/* Address to free for c_name and c_namelist */
115 	char *c_name;		/* Hostname of connection for errors */
116 	char *c_namelist;	/* Pointer to other possible addresses */
117 	char *c_output_name;	/* Hostname of connection for output */
118 	char *c_data;		/* Data read from this fd */
119 	struct ssh *c_ssh;	/* SSH-connection */
120 	struct timespec c_ts;	/* Time at which connection gets aborted */
121 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
122 } con;
123 
124 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
125 con *fdcon;
126 
127 static void keyprint(con *c, struct sshkey *key);
128 
129 static int
130 fdlim_get(int hard)
131 {
132 	struct rlimit rlfd;
133 
134 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
135 		return (-1);
136 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY ||
137 	    (hard ? rlfd.rlim_max : rlfd.rlim_cur) > INT_MAX)
138 		return sysconf(_SC_OPEN_MAX);
139 	return hard ? rlfd.rlim_max : rlfd.rlim_cur;
140 }
141 
142 static int
143 fdlim_set(int lim)
144 {
145 	struct rlimit rlfd;
146 
147 	if (lim <= 0)
148 		return (-1);
149 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
150 		return (-1);
151 	rlfd.rlim_cur = lim;
152 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
153 		return (-1);
154 	return (0);
155 }
156 
157 /*
158  * This is an strsep function that returns a null field for adjacent
159  * separators.  This is the same as the 4.4BSD strsep, but different from the
160  * one in the GNU libc.
161  */
162 static char *
163 xstrsep(char **str, const char *delim)
164 {
165 	char *s, *e;
166 
167 	if (!**str)
168 		return (NULL);
169 
170 	s = *str;
171 	e = s + strcspn(s, delim);
172 
173 	if (*e != '\0')
174 		*e++ = '\0';
175 	*str = e;
176 
177 	return (s);
178 }
179 
180 /*
181  * Get the next non-null token (like GNU strsep).  Strsep() will return a
182  * null token for two adjacent separators, so we may have to loop.
183  */
184 static char *
185 strnnsep(char **stringp, const char *delim)
186 {
187 	char *tok;
188 
189 	do {
190 		tok = xstrsep(stringp, delim);
191 	} while (tok && *tok == '\0');
192 	return (tok);
193 }
194 
195 
196 static int
197 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
198 {
199 	con *c;
200 
201 	if ((c = ssh_get_app_data(ssh)) != NULL)
202 		keyprint(c, hostkey);
203 	/* always abort key exchange */
204 	return -1;
205 }
206 
207 static int
208 ssh2_capable(int remote_major, int remote_minor)
209 {
210 	switch (remote_major) {
211 	case 1:
212 		if (remote_minor == 99)
213 			return 1;
214 		break;
215 	case 2:
216 		return 1;
217 	default:
218 		break;
219 	}
220 	return 0;
221 }
222 
223 static void
224 keygrab_ssh2(con *c)
225 {
226 	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
227 	int r;
228 
229 	switch (c->c_keytype) {
230 	case KT_DSA:
231 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
232 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
233 		break;
234 	case KT_RSA:
235 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
236 		    "rsa-sha2-512-cert-v01@openssh.com,"
237 		    "rsa-sha2-256-cert-v01@openssh.com,"
238 		    "ssh-rsa-cert-v01@openssh.com" :
239 		    "rsa-sha2-512,"
240 		    "rsa-sha2-256,"
241 		    "ssh-rsa";
242 		break;
243 	case KT_ED25519:
244 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
245 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
246 		break;
247 	case KT_XMSS:
248 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
249 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
250 		break;
251 	case KT_ECDSA:
252 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
253 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
254 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
255 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
256 		    "ecdsa-sha2-nistp256,"
257 		    "ecdsa-sha2-nistp384,"
258 		    "ecdsa-sha2-nistp521";
259 		break;
260 	case KT_ECDSA_SK:
261 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
262 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
263 		    "sk-ecdsa-sha2-nistp256@openssh.com";
264 		break;
265 	case KT_ED25519_SK:
266 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
267 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
268 		    "sk-ssh-ed25519@openssh.com";
269 		break;
270 	default:
271 		fatal("unknown key type %d", c->c_keytype);
272 		break;
273 	}
274 	if ((r = kex_setup(c->c_ssh, __UNCONST(myproposal))) != 0) {
275 		free(c->c_ssh);
276 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
277 		exit(1);
278 	}
279 #ifdef WITH_OPENSSL
280 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
281 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
282 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
283 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
284 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
285 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
286 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
287 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
288 #endif
289 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
290 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
291 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
292 	/*
293 	 * do the key-exchange until an error occurs or until
294 	 * the key_print_wrapper() callback sets c_done.
295 	 */
296 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
297 }
298 
299 static void
300 keyprint_one(const char *host, struct sshkey *key)
301 {
302 	char *hostport = NULL, *hashed = NULL;
303 	const char *known_host;
304 	int r = 0;
305 
306 	found_one = 1;
307 
308 	if (print_sshfp) {
309 		export_dns_rr(host, key, stdout, 0, hashalg);
310 		return;
311 	}
312 
313 	hostport = put_host_port(host, ssh_port);
314 	lowercase(hostport);
315 	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
316 		fatal("host_hash failed");
317 	known_host = hash_hosts ? hashed : hostport;
318 	if (!get_cert)
319 		r = fprintf(stdout, "%s ", known_host);
320 	if (r >= 0 && sshkey_write(key, stdout) == 0)
321 		(void)fputs("\n", stdout);
322 	free(hashed);
323 	free(hostport);
324 }
325 
326 static void
327 keyprint(con *c, struct sshkey *key)
328 {
329 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
330 	char *host, *ohosts;
331 
332 	if (key == NULL)
333 		return;
334 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
335 		keyprint_one(hosts, key);
336 		return;
337 	}
338 	ohosts = hosts = xstrdup(hosts);
339 	while ((host = strsep(&hosts, ",")) != NULL)
340 		keyprint_one(host, key);
341 	free(ohosts);
342 }
343 
344 static int
345 tcpconnect(char *host)
346 {
347 	struct addrinfo hints, *ai, *aitop;
348 	char strport[NI_MAXSERV];
349 	int gaierr, s = -1;
350 
351 	snprintf(strport, sizeof strport, "%d", ssh_port);
352 	memset(&hints, 0, sizeof(hints));
353 	hints.ai_family = IPv4or6;
354 	hints.ai_socktype = SOCK_STREAM;
355 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
356 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
357 		return -1;
358 	}
359 	for (ai = aitop; ai; ai = ai->ai_next) {
360 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
361 		if (s == -1) {
362 			error("socket: %s", strerror(errno));
363 			continue;
364 		}
365 		if (set_nonblock(s) == -1)
366 			fatal_f("set_nonblock(%d)", s);
367 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
368 		    errno != EINPROGRESS)
369 			error("connect (`%s'): %s", host, strerror(errno));
370 		else
371 			break;
372 		close(s);
373 		s = -1;
374 	}
375 	freeaddrinfo(aitop);
376 	return s;
377 }
378 
379 static int
380 conalloc(const char *iname, const char *oname, int keytype)
381 {
382 	char *namebase, *name, *namelist;
383 	int s;
384 
385 	namebase = namelist = xstrdup(iname);
386 
387 	do {
388 		name = xstrsep(&namelist, ",");
389 		if (!name) {
390 			free(namebase);
391 			return (-1);
392 		}
393 	} while ((s = tcpconnect(name)) < 0);
394 
395 	if (s >= maxfd)
396 		fatal("conalloc: fdno %d too high", s);
397 	if (fdcon[s].c_status)
398 		fatal("conalloc: attempt to reuse fdno %d", s);
399 
400 	debug3_f("oname %s kt %d", oname, keytype);
401 	fdcon[s].c_fd = s;
402 	fdcon[s].c_status = CS_CON;
403 	fdcon[s].c_namebase = namebase;
404 	fdcon[s].c_name = name;
405 	fdcon[s].c_namelist = namelist;
406 	fdcon[s].c_output_name = xstrdup(oname);
407 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
408 	fdcon[s].c_len = 4;
409 	fdcon[s].c_off = 0;
410 	fdcon[s].c_keytype = keytype;
411 	monotime_ts(&fdcon[s].c_ts);
412 	fdcon[s].c_ts.tv_sec += timeout;
413 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
414 	read_wait[s].fd = s;
415 	read_wait[s].events = POLLIN;
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 	free(fdcon[s].c_namebase);
426 	free(fdcon[s].c_output_name);
427 	if (fdcon[s].c_status == CS_KEYS)
428 		free(fdcon[s].c_data);
429 	fdcon[s].c_status = CS_UNUSED;
430 	fdcon[s].c_keytype = 0;
431 	if (fdcon[s].c_ssh) {
432 		ssh_packet_close(fdcon[s].c_ssh);
433 		free(fdcon[s].c_ssh);
434 		fdcon[s].c_ssh = NULL;
435 	} else
436 		close(s);
437 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
438 	read_wait[s].fd = -1;
439 	read_wait[s].events = 0;
440 	ncon--;
441 }
442 
443 static void
444 contouch(int s)
445 {
446 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
447 	monotime_ts(&fdcon[s].c_ts);
448 	fdcon[s].c_ts.tv_sec += timeout;
449 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
450 }
451 
452 static int
453 conrecycle(int s)
454 {
455 	con *c = &fdcon[s];
456 	int ret;
457 
458 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
459 	confree(s);
460 	return (ret);
461 }
462 
463 static void
464 congreet(int s)
465 {
466 	int n = 0, remote_major = 0, remote_minor = 0;
467 	char buf[256], *cp;
468 	char remote_version[sizeof buf];
469 	size_t bufsiz;
470 	con *c = &fdcon[s];
471 
472 	/* send client banner */
473 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
474 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
475 	if (n < 0 || (size_t)n >= sizeof(buf)) {
476 		error("snprintf: buffer too small");
477 		confree(s);
478 		return;
479 	}
480 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
481 		error("write (%s): %s", c->c_name, strerror(errno));
482 		confree(s);
483 		return;
484 	}
485 
486 	/*
487 	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
488 	 * protocol identification string may be preceded by an arbitrarily
489 	 * large banner which we must read and ignore.  Loop while reading
490 	 * newline-terminated lines until we have one starting with "SSH-".
491 	 * The ID string cannot be longer than 255 characters although the
492 	 * preceding banner lines may (in which case they'll be discarded
493 	 * in multiple iterations of the outer loop).
494 	 */
495 	for (;;) {
496 		memset(buf, '\0', sizeof(buf));
497 		bufsiz = sizeof(buf);
498 		cp = buf;
499 		while (bufsiz-- &&
500 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
501 			if (*cp == '\r')
502 				*cp = '\n';
503 			cp++;
504 		}
505 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
506 			break;
507 	}
508 	if (n == 0) {
509 		switch (errno) {
510 		case EPIPE:
511 			error("%s: Connection closed by remote host", c->c_name);
512 			break;
513 		case ECONNREFUSED:
514 			break;
515 		default:
516 			error("read (%s): %s", c->c_name, strerror(errno));
517 			break;
518 		}
519 		conrecycle(s);
520 		return;
521 	}
522 	if (cp >= buf + sizeof(buf)) {
523 		error("%s: greeting exceeds allowable length", c->c_name);
524 		confree(s);
525 		return;
526 	}
527 	if (*cp != '\n' && *cp != '\r') {
528 		error("%s: bad greeting", c->c_name);
529 		confree(s);
530 		return;
531 	}
532 	*cp = '\0';
533 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
534 		fatal("ssh_packet_set_connection failed");
535 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
536 	ssh_set_app_data(c->c_ssh, c);	/* back link */
537 	c->c_ssh->compat = 0;
538 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
539 	    &remote_major, &remote_minor, remote_version) == 3)
540 		compat_banner(c->c_ssh, remote_version);
541 	if (!ssh2_capable(remote_major, remote_minor)) {
542 		debug("%s doesn't support ssh2", c->c_name);
543 		confree(s);
544 		return;
545 	}
546 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
547 	    c->c_name, ssh_port, chop(buf));
548 	keygrab_ssh2(c);
549 	confree(s);
550 }
551 
552 static void
553 conread(int s)
554 {
555 	con *c = &fdcon[s];
556 	size_t n;
557 
558 	if (c->c_status == CS_CON) {
559 		congreet(s);
560 		return;
561 	}
562 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
563 	if (n == 0) {
564 		error("read (%s): %s", c->c_name, strerror(errno));
565 		confree(s);
566 		return;
567 	}
568 	c->c_off += n;
569 
570 	if (c->c_off == c->c_len)
571 		switch (c->c_status) {
572 		case CS_SIZE:
573 			c->c_plen = htonl(c->c_plen);
574 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
575 			c->c_off = 0;
576 			c->c_data = xmalloc(c->c_len);
577 			c->c_status = CS_KEYS;
578 			break;
579 		default:
580 			fatal("conread: invalid status %d", c->c_status);
581 			break;
582 		}
583 
584 	contouch(s);
585 }
586 
587 static void
588 conloop(void)
589 {
590 	struct timespec seltime, now;
591 	con *c;
592 	int i;
593 
594 	monotime_ts(&now);
595 	c = TAILQ_FIRST(&tq);
596 
597 	if (c && timespeccmp(&c->c_ts, &now, >))
598 		timespecsub(&c->c_ts, &now, &seltime);
599 	else
600 		timespecclear(&seltime);
601 
602 	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
603 		if (errno == EAGAIN || errno == EINTR)
604 			continue;
605 		error("poll error");
606 	}
607 
608 	for (i = 0; i < maxfd; i++) {
609 		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
610 			confree(i);
611 		else if (read_wait[i].revents & (POLLIN|POLLHUP))
612 			conread(i);
613 	}
614 
615 	c = TAILQ_FIRST(&tq);
616 	while (c && timespeccmp(&c->c_ts, &now, <)) {
617 		int s = c->c_fd;
618 
619 		c = TAILQ_NEXT(c, c_link);
620 		conrecycle(s);
621 	}
622 }
623 
624 static void
625 do_one_host(char *host)
626 {
627 	char *name = strnnsep(&host, " \t\n");
628 	int j;
629 
630 	if (name == NULL)
631 		return;
632 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
633 		if (get_keytypes & j) {
634 			while (ncon >= MAXCON)
635 				conloop();
636 			conalloc(name, *host ? host : name, j);
637 		}
638 	}
639 }
640 
641 static void
642 do_host(char *host)
643 {
644 	char daddr[128];
645 	struct xaddr addr, end_addr;
646 	u_int masklen;
647 
648 	if (host == NULL)
649 		return;
650 	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
651 		/* Assume argument is a hostname */
652 		do_one_host(host);
653 	} else {
654 		/* Argument is a CIDR range */
655 		debug("CIDR range %s", host);
656 		end_addr = addr;
657 		if (addr_host_to_all1s(&end_addr, masklen) != 0)
658 			goto badaddr;
659 		/*
660 		 * Note: we deliberately include the all-zero/ones addresses.
661 		 */
662 		for (;;) {
663 			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
664  badaddr:
665 				error("Invalid address %s", host);
666 				return;
667 			}
668 			debug("CIDR expand: address %s", daddr);
669 			do_one_host(daddr);
670 			if (addr_cmp(&addr, &end_addr) == 0)
671 				break;
672 			addr_increment(&addr);
673 		};
674 	}
675 }
676 
677 void
678 sshfatal(const char *file, const char *func, int line, int showfunc,
679     LogLevel level, const char *suffix, const char *fmt, ...)
680 {
681 	va_list args;
682 
683 	va_start(args, fmt);
684 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
685 	va_end(args);
686 	cleanup_exit(255);
687 }
688 
689 __dead static void
690 usage(void)
691 {
692 	fprintf(stderr,
693 	    "usage: ssh-keyscan [-46cDHv] [-f file] [-O option] [-p port] [-T timeout]\n"
694 	    "                   [-t type] [host | addrlist namelist]\n");
695 	exit(1);
696 }
697 
698 int
699 main(int argc, char **argv)
700 {
701 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
702 	int opt, fopt_count = 0, j;
703 	char *tname, *cp, *line = NULL;
704 	size_t linesize = 0;
705 	FILE *fp;
706 
707 	extern int optind;
708 	extern char *optarg;
709 
710 	TAILQ_INIT(&tq);
711 
712 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
713 	sanitise_stdfd();
714 
715 	if (argc <= 1)
716 		usage();
717 
718 	while ((opt = getopt(argc, argv, "cDHv46O:p:T:t:f:")) != -1) {
719 		switch (opt) {
720 		case 'H':
721 			hash_hosts = 1;
722 			break;
723 		case 'c':
724 			get_cert = 1;
725 			break;
726 		case 'D':
727 			print_sshfp = 1;
728 			break;
729 		case 'p':
730 			ssh_port = a2port(optarg);
731 			if (ssh_port <= 0) {
732 				fprintf(stderr, "Bad port '%s'\n", optarg);
733 				exit(1);
734 			}
735 			break;
736 		case 'T':
737 			timeout = convtime(optarg);
738 			if (timeout == -1 || timeout == 0) {
739 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
740 				usage();
741 			}
742 			break;
743 		case 'v':
744 			if (!debug_flag) {
745 				debug_flag = 1;
746 				log_level = SYSLOG_LEVEL_DEBUG1;
747 			}
748 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
749 				log_level++;
750 			else
751 				fatal("Too high debugging level.");
752 			break;
753 		case 'f':
754 			if (strcmp(optarg, "-") == 0)
755 				optarg = NULL;
756 			argv[fopt_count++] = optarg;
757 			break;
758 		case 'O':
759 			/* Maybe other misc options in the future too */
760 			if (strncmp(optarg, "hashalg=", 8) != 0)
761 				fatal("Unsupported -O option");
762 			if ((hashalg = ssh_digest_alg_by_name(
763 			    optarg + 8)) == -1)
764 				fatal("Unsupported hash algorithm");
765 			break;
766 		case 't':
767 			get_keytypes = 0;
768 			tname = strtok(optarg, ",");
769 			while (tname) {
770 				int type = sshkey_type_from_name(tname);
771 
772 				switch (type) {
773 #ifdef WITH_DSA
774 				case KEY_DSA:
775 					get_keytypes |= KT_DSA;
776 					break;
777 #endif
778 				case KEY_ECDSA:
779 					get_keytypes |= KT_ECDSA;
780 					break;
781 				case KEY_RSA:
782 					get_keytypes |= KT_RSA;
783 					break;
784 				case KEY_ED25519:
785 					get_keytypes |= KT_ED25519;
786 					break;
787 				case KEY_XMSS:
788 					get_keytypes |= KT_XMSS;
789 					break;
790 				case KEY_ED25519_SK:
791 					get_keytypes |= KT_ED25519_SK;
792 					break;
793 				case KEY_ECDSA_SK:
794 					get_keytypes |= KT_ECDSA_SK;
795 					break;
796 				case KEY_UNSPEC:
797 				default:
798 					fatal("Unknown key type \"%s\"", tname);
799 				}
800 				tname = strtok(NULL, ",");
801 			}
802 			break;
803 		case '4':
804 			IPv4or6 = AF_INET;
805 			break;
806 		case '6':
807 			IPv4or6 = AF_INET6;
808 			break;
809 		default:
810 			usage();
811 		}
812 	}
813 	if (optind == argc && !fopt_count)
814 		usage();
815 
816 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
817 
818 	maxfd = fdlim_get(1);
819 	if (maxfd < 0)
820 		fatal("%s: fdlim_get: bad value", __progname);
821 	if (maxfd > MAXMAXFD)
822 		maxfd = MAXMAXFD;
823 	if (MAXCON <= 0)
824 		fatal("%s: not enough file descriptors", __progname);
825 	if (maxfd > fdlim_get(0))
826 		fdlim_set(maxfd);
827 	fdcon = xcalloc(maxfd, sizeof(con));
828 	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
829 	for (j = 0; j < maxfd; j++)
830 		read_wait[j].fd = -1;
831 
832 	for (j = 0; j < fopt_count; j++) {
833 		if (argv[j] == NULL)
834 			fp = stdin;
835 		else if ((fp = fopen(argv[j], "r")) == NULL)
836 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
837 
838 		while (getline(&line, &linesize, fp) != -1) {
839 			/* Chomp off trailing whitespace and comments */
840 			if ((cp = strchr(line, '#')) == NULL)
841 				cp = line + strlen(line) - 1;
842 			while (cp >= line) {
843 				if (*cp == ' ' || *cp == '\t' ||
844 				    *cp == '\n' || *cp == '#')
845 					*cp-- = '\0';
846 				else
847 					break;
848 			}
849 
850 			/* Skip empty lines */
851 			if (*line == '\0')
852 				continue;
853 
854 			do_host(line);
855 		}
856 
857 		if (ferror(fp))
858 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
859 
860 		fclose(fp);
861 	}
862 	free(line);
863 
864 	while (optind < argc)
865 		do_host(argv[optind++]);
866 
867 	while (ncon > 0)
868 		conloop();
869 
870 	return found_one ? 0 : 1;
871 }
872