xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision 0d66206fff44f864ea8a4b220c3a53b4caa959a0) 
1 /* $OpenBSD: ssh-keyscan.c,v 1.151 2023/02/10 06:41:53 jmc 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 "includes.h"
11 
12 #include <sys/types.h>
13 #include "openbsd-compat/sys-queue.h"
14 #include <sys/resource.h>
15 #ifdef HAVE_SYS_TIME_H
16 # include <sys/time.h>
17 #endif
18 
19 #include <netinet/in.h>
20 #include <arpa/inet.h>
21 
22 #ifdef WITH_OPENSSL
23 #include <openssl/bn.h>
24 #endif
25 
26 #include <netdb.h>
27 #include <errno.h>
28 #ifdef HAVE_POLL_H
29 #include <poll.h>
30 #endif
31 #include <stdarg.h>
32 #include <stdio.h>
33 #include <stdlib.h>
34 #include <signal.h>
35 #include <string.h>
36 #include <unistd.h>
37 
38 #include "xmalloc.h"
39 #include "ssh.h"
40 #include "sshbuf.h"
41 #include "sshkey.h"
42 #include "cipher.h"
43 #include "digest.h"
44 #include "kex.h"
45 #include "compat.h"
46 #include "myproposal.h"
47 #include "packet.h"
48 #include "dispatch.h"
49 #include "log.h"
50 #include "atomicio.h"
51 #include "misc.h"
52 #include "hostfile.h"
53 #include "ssherr.h"
54 #include "ssh_api.h"
55 #include "dns.h"
56 #include "addr.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 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
133 	struct rlimit rlfd;
134 
135 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
136 		return (-1);
137 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
138 		return SSH_SYSFDMAX;
139 	else
140 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
141 #else
142 	return SSH_SYSFDMAX;
143 #endif
144 }
145 
146 static int
147 fdlim_set(int lim)
148 {
149 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
150 	struct rlimit rlfd;
151 #endif
152 
153 	if (lim <= 0)
154 		return (-1);
155 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
156 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
157 		return (-1);
158 	rlfd.rlim_cur = lim;
159 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
160 		return (-1);
161 #elif defined (HAVE_SETDTABLESIZE)
162 	setdtablesize(lim);
163 #endif
164 	return (0);
165 }
166 
167 /*
168  * This is an strsep function that returns a null field for adjacent
169  * separators.  This is the same as the 4.4BSD strsep, but different from the
170  * one in the GNU libc.
171  */
172 static char *
173 xstrsep(char **str, const char *delim)
174 {
175 	char *s, *e;
176 
177 	if (!**str)
178 		return (NULL);
179 
180 	s = *str;
181 	e = s + strcspn(s, delim);
182 
183 	if (*e != '\0')
184 		*e++ = '\0';
185 	*str = e;
186 
187 	return (s);
188 }
189 
190 /*
191  * Get the next non-null token (like GNU strsep).  Strsep() will return a
192  * null token for two adjacent separators, so we may have to loop.
193  */
194 static char *
195 strnnsep(char **stringp, char *delim)
196 {
197 	char *tok;
198 
199 	do {
200 		tok = xstrsep(stringp, delim);
201 	} while (tok && *tok == '\0');
202 	return (tok);
203 }
204 
205 
206 static int
207 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
208 {
209 	con *c;
210 
211 	if ((c = ssh_get_app_data(ssh)) != NULL)
212 		keyprint(c, hostkey);
213 	/* always abort key exchange */
214 	return -1;
215 }
216 
217 static int
218 ssh2_capable(int remote_major, int remote_minor)
219 {
220 	switch (remote_major) {
221 	case 1:
222 		if (remote_minor == 99)
223 			return 1;
224 		break;
225 	case 2:
226 		return 1;
227 	default:
228 		break;
229 	}
230 	return 0;
231 }
232 
233 static void
234 keygrab_ssh2(con *c)
235 {
236 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
237 	int r;
238 
239 	switch (c->c_keytype) {
240 	case KT_DSA:
241 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
242 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
243 		break;
244 	case KT_RSA:
245 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
246 		    "rsa-sha2-512-cert-v01@openssh.com,"
247 		    "rsa-sha2-256-cert-v01@openssh.com,"
248 		    "ssh-rsa-cert-v01@openssh.com" :
249 		    "rsa-sha2-512,"
250 		    "rsa-sha2-256,"
251 		    "ssh-rsa";
252 		break;
253 	case KT_ED25519:
254 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
255 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
256 		break;
257 	case KT_XMSS:
258 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
259 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
260 		break;
261 	case KT_ECDSA:
262 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
263 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
264 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
265 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
266 		    "ecdsa-sha2-nistp256,"
267 		    "ecdsa-sha2-nistp384,"
268 		    "ecdsa-sha2-nistp521";
269 		break;
270 	case KT_ECDSA_SK:
271 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
272 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
273 		    "sk-ecdsa-sha2-nistp256@openssh.com";
274 		break;
275 	case KT_ED25519_SK:
276 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
277 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
278 		    "sk-ssh-ed25519@openssh.com";
279 		break;
280 	default:
281 		fatal("unknown key type %d", c->c_keytype);
282 		break;
283 	}
284 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
285 		free(c->c_ssh);
286 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
287 		exit(1);
288 	}
289 #ifdef WITH_OPENSSL
290 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
291 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
292 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
293 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
294 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
295 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
296 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
297 # ifdef OPENSSL_HAS_ECC
298 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
299 # endif
300 #endif
301 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
302 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
303 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
304 	/*
305 	 * do the key-exchange until an error occurs or until
306 	 * the key_print_wrapper() callback sets c_done.
307 	 */
308 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
309 }
310 
311 static void
312 keyprint_one(const char *host, struct sshkey *key)
313 {
314 	char *hostport = NULL, *hashed = NULL;
315 	const char *known_host;
316 
317 	found_one = 1;
318 
319 	if (print_sshfp) {
320 		export_dns_rr(host, key, stdout, 0, hashalg);
321 		return;
322 	}
323 
324 	hostport = put_host_port(host, ssh_port);
325 	lowercase(hostport);
326 	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
327 		fatal("host_hash failed");
328 	known_host = hash_hosts ? hashed : hostport;
329 	if (!get_cert)
330 		fprintf(stdout, "%s ", known_host);
331 	sshkey_write(key, stdout);
332 	fputs("\n", stdout);
333 	free(hashed);
334 	free(hostport);
335 }
336 
337 static void
338 keyprint(con *c, struct sshkey *key)
339 {
340 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
341 	char *host, *ohosts;
342 
343 	if (key == NULL)
344 		return;
345 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
346 		keyprint_one(hosts, key);
347 		return;
348 	}
349 	ohosts = hosts = xstrdup(hosts);
350 	while ((host = strsep(&hosts, ",")) != NULL)
351 		keyprint_one(host, key);
352 	free(ohosts);
353 }
354 
355 static int
356 tcpconnect(char *host)
357 {
358 	struct addrinfo hints, *ai, *aitop;
359 	char strport[NI_MAXSERV];
360 	int gaierr, s = -1;
361 
362 	snprintf(strport, sizeof strport, "%d", ssh_port);
363 	memset(&hints, 0, sizeof(hints));
364 	hints.ai_family = IPv4or6;
365 	hints.ai_socktype = SOCK_STREAM;
366 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
367 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
368 		return -1;
369 	}
370 	for (ai = aitop; ai; ai = ai->ai_next) {
371 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
372 		if (s == -1) {
373 			error("socket: %s", strerror(errno));
374 			continue;
375 		}
376 		if (set_nonblock(s) == -1)
377 			fatal_f("set_nonblock(%d)", s);
378 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
379 		    errno != EINPROGRESS)
380 			error("connect (`%s'): %s", host, strerror(errno));
381 		else
382 			break;
383 		close(s);
384 		s = -1;
385 	}
386 	freeaddrinfo(aitop);
387 	return s;
388 }
389 
390 static int
391 conalloc(const char *iname, const char *oname, int keytype)
392 {
393 	char *namebase, *name, *namelist;
394 	int s;
395 
396 	namebase = namelist = xstrdup(iname);
397 
398 	do {
399 		name = xstrsep(&namelist, ",");
400 		if (!name) {
401 			free(namebase);
402 			return (-1);
403 		}
404 	} while ((s = tcpconnect(name)) < 0);
405 
406 	if (s >= maxfd)
407 		fatal("conalloc: fdno %d too high", s);
408 	if (fdcon[s].c_status)
409 		fatal("conalloc: attempt to reuse fdno %d", s);
410 
411 	debug3_f("oname %s kt %d", oname, keytype);
412 	fdcon[s].c_fd = s;
413 	fdcon[s].c_status = CS_CON;
414 	fdcon[s].c_namebase = namebase;
415 	fdcon[s].c_name = name;
416 	fdcon[s].c_namelist = namelist;
417 	fdcon[s].c_output_name = xstrdup(oname);
418 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
419 	fdcon[s].c_len = 4;
420 	fdcon[s].c_off = 0;
421 	fdcon[s].c_keytype = keytype;
422 	monotime_ts(&fdcon[s].c_ts);
423 	fdcon[s].c_ts.tv_sec += timeout;
424 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
425 	read_wait[s].fd = s;
426 	read_wait[s].events = POLLIN;
427 	ncon++;
428 	return (s);
429 }
430 
431 static void
432 confree(int s)
433 {
434 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
435 		fatal("confree: attempt to free bad fdno %d", s);
436 	free(fdcon[s].c_namebase);
437 	free(fdcon[s].c_output_name);
438 	if (fdcon[s].c_status == CS_KEYS)
439 		free(fdcon[s].c_data);
440 	fdcon[s].c_status = CS_UNUSED;
441 	fdcon[s].c_keytype = 0;
442 	if (fdcon[s].c_ssh) {
443 		ssh_packet_close(fdcon[s].c_ssh);
444 		free(fdcon[s].c_ssh);
445 		fdcon[s].c_ssh = NULL;
446 	} else
447 		close(s);
448 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
449 	read_wait[s].fd = -1;
450 	read_wait[s].events = 0;
451 	ncon--;
452 }
453 
454 static void
455 contouch(int s)
456 {
457 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
458 	monotime_ts(&fdcon[s].c_ts);
459 	fdcon[s].c_ts.tv_sec += timeout;
460 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
461 }
462 
463 static int
464 conrecycle(int s)
465 {
466 	con *c = &fdcon[s];
467 	int ret;
468 
469 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
470 	confree(s);
471 	return (ret);
472 }
473 
474 static void
475 congreet(int s)
476 {
477 	int n = 0, remote_major = 0, remote_minor = 0;
478 	char buf[256], *cp;
479 	char remote_version[sizeof buf];
480 	size_t bufsiz;
481 	con *c = &fdcon[s];
482 
483 	/* send client banner */
484 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
485 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
486 	if (n < 0 || (size_t)n >= sizeof(buf)) {
487 		error("snprintf: buffer too small");
488 		confree(s);
489 		return;
490 	}
491 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
492 		error("write (%s): %s", c->c_name, strerror(errno));
493 		confree(s);
494 		return;
495 	}
496 
497 	/*
498 	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
499 	 * protocol identification string may be preceeded by an arbitrarily
500 	 * large banner which we must read and ignore.  Loop while reading
501 	 * newline-terminated lines until we have one starting with "SSH-".
502 	 * The ID string cannot be longer than 255 characters although the
503 	 * preceeding banner lines may (in which case they'll be discarded
504 	 * in multiple iterations of the outer loop).
505 	 */
506 	for (;;) {
507 		memset(buf, '\0', sizeof(buf));
508 		bufsiz = sizeof(buf);
509 		cp = buf;
510 		while (bufsiz-- &&
511 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
512 			if (*cp == '\r')
513 				*cp = '\n';
514 			cp++;
515 		}
516 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
517 			break;
518 	}
519 	if (n == 0) {
520 		switch (errno) {
521 		case EPIPE:
522 			error("%s: Connection closed by remote host", c->c_name);
523 			break;
524 		case ECONNREFUSED:
525 			break;
526 		default:
527 			error("read (%s): %s", c->c_name, strerror(errno));
528 			break;
529 		}
530 		conrecycle(s);
531 		return;
532 	}
533 	if (cp >= buf + sizeof(buf)) {
534 		error("%s: greeting exceeds allowable length", c->c_name);
535 		confree(s);
536 		return;
537 	}
538 	if (*cp != '\n' && *cp != '\r') {
539 		error("%s: bad greeting", c->c_name);
540 		confree(s);
541 		return;
542 	}
543 	*cp = '\0';
544 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
545 		fatal("ssh_packet_set_connection failed");
546 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
547 	ssh_set_app_data(c->c_ssh, c);	/* back link */
548 	c->c_ssh->compat = 0;
549 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
550 	    &remote_major, &remote_minor, remote_version) == 3)
551 		compat_banner(c->c_ssh, remote_version);
552 	if (!ssh2_capable(remote_major, remote_minor)) {
553 		debug("%s doesn't support ssh2", c->c_name);
554 		confree(s);
555 		return;
556 	}
557 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
558 	    c->c_name, ssh_port, chop(buf));
559 	keygrab_ssh2(c);
560 	confree(s);
561 }
562 
563 static void
564 conread(int s)
565 {
566 	con *c = &fdcon[s];
567 	size_t n;
568 
569 	if (c->c_status == CS_CON) {
570 		congreet(s);
571 		return;
572 	}
573 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
574 	if (n == 0) {
575 		error("read (%s): %s", c->c_name, strerror(errno));
576 		confree(s);
577 		return;
578 	}
579 	c->c_off += n;
580 
581 	if (c->c_off == c->c_len)
582 		switch (c->c_status) {
583 		case CS_SIZE:
584 			c->c_plen = htonl(c->c_plen);
585 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
586 			c->c_off = 0;
587 			c->c_data = xmalloc(c->c_len);
588 			c->c_status = CS_KEYS;
589 			break;
590 		default:
591 			fatal("conread: invalid status %d", c->c_status);
592 			break;
593 		}
594 
595 	contouch(s);
596 }
597 
598 static void
599 conloop(void)
600 {
601 	struct timespec seltime, now;
602 	con *c;
603 	int i;
604 
605 	monotime_ts(&now);
606 	c = TAILQ_FIRST(&tq);
607 
608 	if (c && timespeccmp(&c->c_ts, &now, >))
609 		timespecsub(&c->c_ts, &now, &seltime);
610 	else
611 		timespecclear(&seltime);
612 
613 	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
614 		if (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK)
615 			continue;
616 		error("poll error");
617 	}
618 
619 	for (i = 0; i < maxfd; i++) {
620 		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
621 			confree(i);
622 		else if (read_wait[i].revents & (POLLIN|POLLHUP))
623 			conread(i);
624 	}
625 
626 	c = TAILQ_FIRST(&tq);
627 	while (c && timespeccmp(&c->c_ts, &now, <)) {
628 		int s = c->c_fd;
629 
630 		c = TAILQ_NEXT(c, c_link);
631 		conrecycle(s);
632 	}
633 }
634 
635 static void
636 do_one_host(char *host)
637 {
638 	char *name = strnnsep(&host, " \t\n");
639 	int j;
640 
641 	if (name == NULL)
642 		return;
643 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
644 		if (get_keytypes & j) {
645 			while (ncon >= MAXCON)
646 				conloop();
647 			conalloc(name, *host ? host : name, j);
648 		}
649 	}
650 }
651 
652 static void
653 do_host(char *host)
654 {
655 	char daddr[128];
656 	struct xaddr addr, end_addr;
657 	u_int masklen;
658 
659 	if (host == NULL)
660 		return;
661 	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
662 		/* Assume argument is a hostname */
663 		do_one_host(host);
664 	} else {
665 		/* Argument is a CIDR range */
666 		debug("CIDR range %s", host);
667 		end_addr = addr;
668 		if (addr_host_to_all1s(&end_addr, masklen) != 0)
669 			goto badaddr;
670 		/*
671 		 * Note: we deliberately include the all-zero/ones addresses.
672 		 */
673 		for (;;) {
674 			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
675  badaddr:
676 				error("Invalid address %s", host);
677 				return;
678 			}
679 			debug("CIDR expand: address %s", daddr);
680 			do_one_host(daddr);
681 			if (addr_cmp(&addr, &end_addr) == 0)
682 				break;
683 			addr_increment(&addr);
684 		};
685 	}
686 }
687 
688 void
689 sshfatal(const char *file, const char *func, int line, int showfunc,
690     LogLevel level, const char *suffix, const char *fmt, ...)
691 {
692 	va_list args;
693 
694 	va_start(args, fmt);
695 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
696 	va_end(args);
697 	cleanup_exit(255);
698 }
699 
700 static void
701 usage(void)
702 {
703 	fprintf(stderr,
704 	    "usage: ssh-keyscan [-46cDHv] [-f file] [-O option] [-p port] [-T timeout]\n"
705 	    "                   [-t type] [host | addrlist namelist]\n");
706 	exit(1);
707 }
708 
709 int
710 main(int argc, char **argv)
711 {
712 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
713 	int opt, fopt_count = 0, j;
714 	char *tname, *cp, *line = NULL;
715 	size_t linesize = 0;
716 	FILE *fp;
717 
718 	extern int optind;
719 	extern char *optarg;
720 
721 	__progname = ssh_get_progname(argv[0]);
722 	seed_rng();
723 	TAILQ_INIT(&tq);
724 
725 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
726 	sanitise_stdfd();
727 
728 	if (argc <= 1)
729 		usage();
730 
731 	while ((opt = getopt(argc, argv, "cDHv46O:p:T:t:f:")) != -1) {
732 		switch (opt) {
733 		case 'H':
734 			hash_hosts = 1;
735 			break;
736 		case 'c':
737 			get_cert = 1;
738 			break;
739 		case 'D':
740 			print_sshfp = 1;
741 			break;
742 		case 'p':
743 			ssh_port = a2port(optarg);
744 			if (ssh_port <= 0) {
745 				fprintf(stderr, "Bad port '%s'\n", optarg);
746 				exit(1);
747 			}
748 			break;
749 		case 'T':
750 			timeout = convtime(optarg);
751 			if (timeout == -1 || timeout == 0) {
752 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
753 				usage();
754 			}
755 			break;
756 		case 'v':
757 			if (!debug_flag) {
758 				debug_flag = 1;
759 				log_level = SYSLOG_LEVEL_DEBUG1;
760 			}
761 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
762 				log_level++;
763 			else
764 				fatal("Too high debugging level.");
765 			break;
766 		case 'f':
767 			if (strcmp(optarg, "-") == 0)
768 				optarg = NULL;
769 			argv[fopt_count++] = optarg;
770 			break;
771 		case 'O':
772 			/* Maybe other misc options in the future too */
773 			if (strncmp(optarg, "hashalg=", 8) != 0)
774 				fatal("Unsupported -O option");
775 			if ((hashalg = ssh_digest_alg_by_name(
776 			    optarg + 8)) == -1)
777 				fatal("Unsupported hash algorithm");
778 			break;
779 		case 't':
780 			get_keytypes = 0;
781 			tname = strtok(optarg, ",");
782 			while (tname) {
783 				int type = sshkey_type_from_name(tname);
784 
785 				switch (type) {
786 				case KEY_DSA:
787 					get_keytypes |= KT_DSA;
788 					break;
789 				case KEY_ECDSA:
790 					get_keytypes |= KT_ECDSA;
791 					break;
792 				case KEY_RSA:
793 					get_keytypes |= KT_RSA;
794 					break;
795 				case KEY_ED25519:
796 					get_keytypes |= KT_ED25519;
797 					break;
798 				case KEY_XMSS:
799 					get_keytypes |= KT_XMSS;
800 					break;
801 				case KEY_ED25519_SK:
802 					get_keytypes |= KT_ED25519_SK;
803 					break;
804 				case KEY_ECDSA_SK:
805 					get_keytypes |= KT_ECDSA_SK;
806 					break;
807 				case KEY_UNSPEC:
808 				default:
809 					fatal("Unknown key type \"%s\"", tname);
810 				}
811 				tname = strtok(NULL, ",");
812 			}
813 			break;
814 		case '4':
815 			IPv4or6 = AF_INET;
816 			break;
817 		case '6':
818 			IPv4or6 = AF_INET6;
819 			break;
820 		default:
821 			usage();
822 		}
823 	}
824 	if (optind == argc && !fopt_count)
825 		usage();
826 
827 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
828 
829 	maxfd = fdlim_get(1);
830 	if (maxfd < 0)
831 		fatal("%s: fdlim_get: bad value", __progname);
832 	if (maxfd > MAXMAXFD)
833 		maxfd = MAXMAXFD;
834 	if (MAXCON <= 0)
835 		fatal("%s: not enough file descriptors", __progname);
836 	if (maxfd > fdlim_get(0))
837 		fdlim_set(maxfd);
838 	fdcon = xcalloc(maxfd, sizeof(con));
839 	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
840 	for (j = 0; j < maxfd; j++)
841 		read_wait[j].fd = -1;
842 
843 	for (j = 0; j < fopt_count; j++) {
844 		if (argv[j] == NULL)
845 			fp = stdin;
846 		else if ((fp = fopen(argv[j], "r")) == NULL)
847 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
848 
849 		while (getline(&line, &linesize, fp) != -1) {
850 			/* Chomp off trailing whitespace and comments */
851 			if ((cp = strchr(line, '#')) == NULL)
852 				cp = line + strlen(line) - 1;
853 			while (cp >= line) {
854 				if (*cp == ' ' || *cp == '\t' ||
855 				    *cp == '\n' || *cp == '#')
856 					*cp-- = '\0';
857 				else
858 					break;
859 			}
860 
861 			/* Skip empty lines */
862 			if (*line == '\0')
863 				continue;
864 
865 			do_host(line);
866 		}
867 
868 		if (ferror(fp))
869 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
870 
871 		fclose(fp);
872 	}
873 	free(line);
874 
875 	while (optind < argc)
876 		do_host(argv[optind++]);
877 
878 	while (ncon > 0)
879 		conloop();
880 
881 	return found_one ? 0 : 1;
882 }
883