xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision 41059135ce931c0f1014a999ffabc6bc470ce856)
1 /* $OpenBSD: ssh-keyscan.c,v 1.106 2016/05/02 10:26:04 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 "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 #include <openssl/bn.h>
23 
24 #include <netdb.h>
25 #include <errno.h>
26 #include <stdarg.h>
27 #include <stdio.h>
28 #include <stdlib.h>
29 #include <signal.h>
30 #include <string.h>
31 #include <unistd.h>
32 
33 #include "xmalloc.h"
34 #include "ssh.h"
35 #include "ssh1.h"
36 #include "sshbuf.h"
37 #include "sshkey.h"
38 #include "cipher.h"
39 #include "kex.h"
40 #include "compat.h"
41 #include "myproposal.h"
42 #include "packet.h"
43 #include "dispatch.h"
44 #include "log.h"
45 #include "atomicio.h"
46 #include "misc.h"
47 #include "hostfile.h"
48 #include "ssherr.h"
49 #include "ssh_api.h"
50 
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_RSA1		1
58 #define KT_DSA		2
59 #define KT_RSA		4
60 #define KT_ECDSA	8
61 #define KT_ED25519	16
62 
63 int get_cert = 0;
64 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
65 
66 int hash_hosts = 0;		/* Hash hostname on output */
67 
68 #define MAXMAXFD 256
69 
70 /* The number of seconds after which to give up on a TCP connection */
71 int timeout = 5;
72 
73 int maxfd;
74 #define MAXCON (maxfd - 10)
75 
76 extern char *__progname;
77 fd_set *read_wait;
78 size_t read_wait_nfdset;
79 int ncon;
80 
81 struct ssh *active_state = NULL; /* XXX needed for linking */
82 
83 /*
84  * Keep a connection structure for each file descriptor.  The state
85  * associated with file descriptor n is held in fdcon[n].
86  */
87 typedef struct Connection {
88 	u_char c_status;	/* State of connection on this file desc. */
89 #define CS_UNUSED 0		/* File descriptor unused */
90 #define CS_CON 1		/* Waiting to connect/read greeting */
91 #define CS_SIZE 2		/* Waiting to read initial packet size */
92 #define CS_KEYS 3		/* Waiting to read public key packet */
93 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
94 	int c_plen;		/* Packet length field for ssh packet */
95 	int c_len;		/* Total bytes which must be read. */
96 	int c_off;		/* Length of data read so far. */
97 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
98 	sig_atomic_t c_done;	/* SSH2 done */
99 	char *c_namebase;	/* Address to free for c_name and c_namelist */
100 	char *c_name;		/* Hostname of connection for errors */
101 	char *c_namelist;	/* Pointer to other possible addresses */
102 	char *c_output_name;	/* Hostname of connection for output */
103 	char *c_data;		/* Data read from this fd */
104 	struct ssh *c_ssh;	/* SSH-connection */
105 	struct timeval c_tv;	/* Time at which connection gets aborted */
106 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
107 } con;
108 
109 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
110 con *fdcon;
111 
112 static void keyprint(con *c, struct sshkey *key);
113 
114 static int
115 fdlim_get(int hard)
116 {
117 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
118 	struct rlimit rlfd;
119 
120 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
121 		return (-1);
122 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
123 		return SSH_SYSFDMAX;
124 	else
125 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
126 #else
127 	return SSH_SYSFDMAX;
128 #endif
129 }
130 
131 static int
132 fdlim_set(int lim)
133 {
134 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
135 	struct rlimit rlfd;
136 #endif
137 
138 	if (lim <= 0)
139 		return (-1);
140 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
141 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
142 		return (-1);
143 	rlfd.rlim_cur = lim;
144 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
145 		return (-1);
146 #elif defined (HAVE_SETDTABLESIZE)
147 	setdtablesize(lim);
148 #endif
149 	return (0);
150 }
151 
152 /*
153  * This is an strsep function that returns a null field for adjacent
154  * separators.  This is the same as the 4.4BSD strsep, but different from the
155  * one in the GNU libc.
156  */
157 static char *
158 xstrsep(char **str, const char *delim)
159 {
160 	char *s, *e;
161 
162 	if (!**str)
163 		return (NULL);
164 
165 	s = *str;
166 	e = s + strcspn(s, delim);
167 
168 	if (*e != '\0')
169 		*e++ = '\0';
170 	*str = e;
171 
172 	return (s);
173 }
174 
175 /*
176  * Get the next non-null token (like GNU strsep).  Strsep() will return a
177  * null token for two adjacent separators, so we may have to loop.
178  */
179 static char *
180 strnnsep(char **stringp, char *delim)
181 {
182 	char *tok;
183 
184 	do {
185 		tok = xstrsep(stringp, delim);
186 	} while (tok && *tok == '\0');
187 	return (tok);
188 }
189 
190 #ifdef WITH_SSH1
191 static struct sshkey *
192 keygrab_ssh1(con *c)
193 {
194 	static struct sshkey *rsa;
195 	static struct sshbuf *msg;
196 	int r;
197 	u_char type;
198 
199 	if (rsa == NULL) {
200 		if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
201 			error("%s: sshkey_new failed", __func__);
202 			return NULL;
203 		}
204 		if ((msg = sshbuf_new()) == NULL)
205 			fatal("%s: sshbuf_new failed", __func__);
206 	}
207 	if ((r = sshbuf_put(msg, c->c_data, c->c_plen)) != 0 ||
208 	    (r = sshbuf_consume(msg, 8 - (c->c_plen & 7))) != 0 || /* padding */
209 	    (r = sshbuf_get_u8(msg, &type)) != 0)
210 		goto buf_err;
211 	if (type != (int) SSH_SMSG_PUBLIC_KEY) {
212 		error("%s: invalid packet type", c->c_name);
213 		sshbuf_reset(msg);
214 		return NULL;
215 	}
216 	if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
217 	    /* server key */
218 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
219 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
220 	    (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
221 	    /* host key */
222 	    (r = sshbuf_get_u32(msg, NULL)) != 0 ||
223 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->e)) != 0 ||
224 	    (r = sshbuf_get_bignum1(msg, rsa->rsa->n)) != 0) {
225  buf_err:
226 		error("%s: buffer error: %s", __func__, ssh_err(r));
227 		sshbuf_reset(msg);
228 		return NULL;
229 	}
230 
231 	sshbuf_reset(msg);
232 
233 	return (rsa);
234 }
235 #endif
236 
237 static int
238 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
239 {
240 	con *c;
241 
242 	if ((c = ssh_get_app_data(ssh)) != NULL)
243 		keyprint(c, hostkey);
244 	/* always abort key exchange */
245 	return -1;
246 }
247 
248 static int
249 ssh2_capable(int remote_major, int remote_minor)
250 {
251 	switch (remote_major) {
252 	case 1:
253 		if (remote_minor == 99)
254 			return 1;
255 		break;
256 	case 2:
257 		return 1;
258 	default:
259 		break;
260 	}
261 	return 0;
262 }
263 
264 static void
265 keygrab_ssh2(con *c)
266 {
267 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
268 	int r;
269 
270 	enable_compat20();
271 	switch (c->c_keytype) {
272 	case KT_DSA:
273 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
274 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
275 		break;
276 	case KT_RSA:
277 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
278 		    "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
279 		break;
280 	case KT_ED25519:
281 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
282 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
283 		break;
284 	case KT_ECDSA:
285 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
286 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
287 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
288 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
289 		    "ecdsa-sha2-nistp256,"
290 		    "ecdsa-sha2-nistp384,"
291 		    "ecdsa-sha2-nistp521";
292 		break;
293 	default:
294 		fatal("unknown key type %d", c->c_keytype);
295 		break;
296 	}
297 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
298 		free(c->c_ssh);
299 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
300 		exit(1);
301 	}
302 #ifdef WITH_OPENSSL
303 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
304 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
305 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
306 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
307 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
308 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
309 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
310 # ifdef OPENSSL_HAS_ECC
311 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
312 # endif
313 #endif
314 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
315 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
316 	/*
317 	 * do the key-exchange until an error occurs or until
318 	 * the key_print_wrapper() callback sets c_done.
319 	 */
320 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
321 }
322 
323 static void
324 keyprint_one(char *host, struct sshkey *key)
325 {
326 	char *hostport;
327 
328 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
329 		fatal("host_hash failed");
330 
331 	hostport = put_host_port(host, ssh_port);
332 	if (!get_cert)
333 		fprintf(stdout, "%s ", hostport);
334 	sshkey_write(key, stdout);
335 	fputs("\n", stdout);
336 	free(hostport);
337 }
338 
339 static void
340 keyprint(con *c, struct sshkey *key)
341 {
342 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
343 	char *host, *ohosts;
344 
345 	if (key == NULL)
346 		return;
347 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
348 		keyprint_one(hosts, key);
349 		return;
350 	}
351 	ohosts = hosts = xstrdup(hosts);
352 	while ((host = strsep(&hosts, ",")) != NULL)
353 		keyprint_one(host, key);
354 	free(ohosts);
355 }
356 
357 static int
358 tcpconnect(char *host)
359 {
360 	struct addrinfo hints, *ai, *aitop;
361 	char strport[NI_MAXSERV];
362 	int gaierr, s = -1;
363 
364 	snprintf(strport, sizeof strport, "%d", ssh_port);
365 	memset(&hints, 0, sizeof(hints));
366 	hints.ai_family = IPv4or6;
367 	hints.ai_socktype = SOCK_STREAM;
368 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
369 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
370 		return -1;
371 	}
372 	for (ai = aitop; ai; ai = ai->ai_next) {
373 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
374 		if (s < 0) {
375 			error("socket: %s", strerror(errno));
376 			continue;
377 		}
378 		if (set_nonblock(s) == -1)
379 			fatal("%s: set_nonblock(%d)", __func__, s);
380 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
381 		    errno != EINPROGRESS)
382 			error("connect (`%s'): %s", host, strerror(errno));
383 		else
384 			break;
385 		close(s);
386 		s = -1;
387 	}
388 	freeaddrinfo(aitop);
389 	return s;
390 }
391 
392 static int
393 conalloc(char *iname, char *oname, int keytype)
394 {
395 	char *namebase, *name, *namelist;
396 	int s;
397 
398 	namebase = namelist = xstrdup(iname);
399 
400 	do {
401 		name = xstrsep(&namelist, ",");
402 		if (!name) {
403 			free(namebase);
404 			return (-1);
405 		}
406 	} while ((s = tcpconnect(name)) < 0);
407 
408 	if (s >= maxfd)
409 		fatal("conalloc: fdno %d too high", s);
410 	if (fdcon[s].c_status)
411 		fatal("conalloc: attempt to reuse fdno %d", s);
412 
413 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
414 	fdcon[s].c_fd = s;
415 	fdcon[s].c_status = CS_CON;
416 	fdcon[s].c_namebase = namebase;
417 	fdcon[s].c_name = name;
418 	fdcon[s].c_namelist = namelist;
419 	fdcon[s].c_output_name = xstrdup(oname);
420 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
421 	fdcon[s].c_len = 4;
422 	fdcon[s].c_off = 0;
423 	fdcon[s].c_keytype = keytype;
424 	gettimeofday(&fdcon[s].c_tv, NULL);
425 	fdcon[s].c_tv.tv_sec += timeout;
426 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
427 	FD_SET(s, read_wait);
428 	ncon++;
429 	return (s);
430 }
431 
432 static void
433 confree(int s)
434 {
435 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
436 		fatal("confree: attempt to free bad fdno %d", s);
437 	close(s);
438 	free(fdcon[s].c_namebase);
439 	free(fdcon[s].c_output_name);
440 	if (fdcon[s].c_status == CS_KEYS)
441 		free(fdcon[s].c_data);
442 	fdcon[s].c_status = CS_UNUSED;
443 	fdcon[s].c_keytype = 0;
444 	if (fdcon[s].c_ssh) {
445 		ssh_packet_close(fdcon[s].c_ssh);
446 		free(fdcon[s].c_ssh);
447 		fdcon[s].c_ssh = NULL;
448 	}
449 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
450 	FD_CLR(s, read_wait);
451 	ncon--;
452 }
453 
454 static void
455 contouch(int s)
456 {
457 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
458 	gettimeofday(&fdcon[s].c_tv, NULL);
459 	fdcon[s].c_tv.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 	for (;;) {
484 		memset(buf, '\0', sizeof(buf));
485 		bufsiz = sizeof(buf);
486 		cp = buf;
487 		while (bufsiz-- &&
488 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
489 			if (*cp == '\r')
490 				*cp = '\n';
491 			cp++;
492 		}
493 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
494 			break;
495 	}
496 	if (n == 0) {
497 		switch (errno) {
498 		case EPIPE:
499 			error("%s: Connection closed by remote host", c->c_name);
500 			break;
501 		case ECONNREFUSED:
502 			break;
503 		default:
504 			error("read (%s): %s", c->c_name, strerror(errno));
505 			break;
506 		}
507 		conrecycle(s);
508 		return;
509 	}
510 	if (*cp != '\n' && *cp != '\r') {
511 		error("%s: bad greeting", c->c_name);
512 		confree(s);
513 		return;
514 	}
515 	*cp = '\0';
516 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
517 		fatal("ssh_packet_set_connection failed");
518 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
519 	ssh_set_app_data(c->c_ssh, c);	/* back link */
520 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
521 	    &remote_major, &remote_minor, remote_version) == 3)
522 		c->c_ssh->compat = compat_datafellows(remote_version);
523 	else
524 		c->c_ssh->compat = 0;
525 	if (c->c_keytype != KT_RSA1) {
526 		if (!ssh2_capable(remote_major, remote_minor)) {
527 			debug("%s doesn't support ssh2", c->c_name);
528 			confree(s);
529 			return;
530 		}
531 	} else if (remote_major != 1) {
532 		debug("%s doesn't support ssh1", c->c_name);
533 		confree(s);
534 		return;
535 	}
536 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
537 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
538 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
539 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
540 	if (n < 0 || (size_t)n >= sizeof(buf)) {
541 		error("snprintf: buffer too small");
542 		confree(s);
543 		return;
544 	}
545 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
546 		error("write (%s): %s", c->c_name, strerror(errno));
547 		confree(s);
548 		return;
549 	}
550 	if (c->c_keytype != KT_RSA1) {
551 		keygrab_ssh2(c);
552 		confree(s);
553 		return;
554 	}
555 	c->c_status = CS_SIZE;
556 	contouch(s);
557 }
558 
559 static void
560 conread(int s)
561 {
562 	con *c = &fdcon[s];
563 	size_t n;
564 
565 	if (c->c_status == CS_CON) {
566 		congreet(s);
567 		return;
568 	}
569 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
570 	if (n == 0) {
571 		error("read (%s): %s", c->c_name, strerror(errno));
572 		confree(s);
573 		return;
574 	}
575 	c->c_off += n;
576 
577 	if (c->c_off == c->c_len)
578 		switch (c->c_status) {
579 		case CS_SIZE:
580 			c->c_plen = htonl(c->c_plen);
581 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
582 			c->c_off = 0;
583 			c->c_data = xmalloc(c->c_len);
584 			c->c_status = CS_KEYS;
585 			break;
586 #ifdef WITH_SSH1
587 		case CS_KEYS:
588 			keyprint(c, keygrab_ssh1(c));
589 			confree(s);
590 			return;
591 #endif
592 		default:
593 			fatal("conread: invalid status %d", c->c_status);
594 			break;
595 		}
596 
597 	contouch(s);
598 }
599 
600 static void
601 conloop(void)
602 {
603 	struct timeval seltime, now;
604 	fd_set *r, *e;
605 	con *c;
606 	int i;
607 
608 	gettimeofday(&now, NULL);
609 	c = TAILQ_FIRST(&tq);
610 
611 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
612 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
613 		seltime = c->c_tv;
614 		seltime.tv_sec -= now.tv_sec;
615 		seltime.tv_usec -= now.tv_usec;
616 		if (seltime.tv_usec < 0) {
617 			seltime.tv_usec += 1000000;
618 			seltime.tv_sec--;
619 		}
620 	} else
621 		timerclear(&seltime);
622 
623 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
624 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
625 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
626 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
627 
628 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
629 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
630 		;
631 
632 	for (i = 0; i < maxfd; i++) {
633 		if (FD_ISSET(i, e)) {
634 			error("%s: exception!", fdcon[i].c_name);
635 			confree(i);
636 		} else if (FD_ISSET(i, r))
637 			conread(i);
638 	}
639 	free(r);
640 	free(e);
641 
642 	c = TAILQ_FIRST(&tq);
643 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
644 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
645 		int s = c->c_fd;
646 
647 		c = TAILQ_NEXT(c, c_link);
648 		conrecycle(s);
649 	}
650 }
651 
652 static void
653 do_host(char *host)
654 {
655 	char *name = strnnsep(&host, " \t\n");
656 	int j;
657 
658 	if (name == NULL)
659 		return;
660 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
661 		if (get_keytypes & j) {
662 			while (ncon >= MAXCON)
663 				conloop();
664 			conalloc(name, *host ? host : name, j);
665 		}
666 	}
667 }
668 
669 void
670 fatal(const char *fmt,...)
671 {
672 	va_list args;
673 
674 	va_start(args, fmt);
675 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
676 	va_end(args);
677 	exit(255);
678 }
679 
680 static void
681 usage(void)
682 {
683 	fprintf(stderr,
684 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
685 	    "\t\t   [host | addrlist namelist] ...\n",
686 	    __progname);
687 	exit(1);
688 }
689 
690 int
691 main(int argc, char **argv)
692 {
693 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
694 	int opt, fopt_count = 0, j;
695 	char *tname, *cp, line[NI_MAXHOST];
696 	FILE *fp;
697 	u_long linenum;
698 
699 	extern int optind;
700 	extern char *optarg;
701 
702 	ssh_malloc_init();	/* must be called before any mallocs */
703 	__progname = ssh_get_progname(argv[0]);
704 	seed_rng();
705 	TAILQ_INIT(&tq);
706 
707 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
708 	sanitise_stdfd();
709 
710 	if (argc <= 1)
711 		usage();
712 
713 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
714 		switch (opt) {
715 		case 'H':
716 			hash_hosts = 1;
717 			break;
718 		case 'c':
719 			get_cert = 1;
720 			break;
721 		case 'p':
722 			ssh_port = a2port(optarg);
723 			if (ssh_port <= 0) {
724 				fprintf(stderr, "Bad port '%s'\n", optarg);
725 				exit(1);
726 			}
727 			break;
728 		case 'T':
729 			timeout = convtime(optarg);
730 			if (timeout == -1 || timeout == 0) {
731 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
732 				usage();
733 			}
734 			break;
735 		case 'v':
736 			if (!debug_flag) {
737 				debug_flag = 1;
738 				log_level = SYSLOG_LEVEL_DEBUG1;
739 			}
740 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
741 				log_level++;
742 			else
743 				fatal("Too high debugging level.");
744 			break;
745 		case 'f':
746 			if (strcmp(optarg, "-") == 0)
747 				optarg = NULL;
748 			argv[fopt_count++] = optarg;
749 			break;
750 		case 't':
751 			get_keytypes = 0;
752 			tname = strtok(optarg, ",");
753 			while (tname) {
754 				int type = sshkey_type_from_name(tname);
755 				switch (type) {
756 				case KEY_RSA1:
757 					get_keytypes |= KT_RSA1;
758 					break;
759 				case KEY_DSA:
760 					get_keytypes |= KT_DSA;
761 					break;
762 				case KEY_ECDSA:
763 					get_keytypes |= KT_ECDSA;
764 					break;
765 				case KEY_RSA:
766 					get_keytypes |= KT_RSA;
767 					break;
768 				case KEY_ED25519:
769 					get_keytypes |= KT_ED25519;
770 					break;
771 				case KEY_UNSPEC:
772 					fatal("unknown key type %s", tname);
773 				}
774 				tname = strtok(NULL, ",");
775 			}
776 			break;
777 		case '4':
778 			IPv4or6 = AF_INET;
779 			break;
780 		case '6':
781 			IPv4or6 = AF_INET6;
782 			break;
783 		case '?':
784 		default:
785 			usage();
786 		}
787 	}
788 	if (optind == argc && !fopt_count)
789 		usage();
790 
791 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
792 
793 	maxfd = fdlim_get(1);
794 	if (maxfd < 0)
795 		fatal("%s: fdlim_get: bad value", __progname);
796 	if (maxfd > MAXMAXFD)
797 		maxfd = MAXMAXFD;
798 	if (MAXCON <= 0)
799 		fatal("%s: not enough file descriptors", __progname);
800 	if (maxfd > fdlim_get(0))
801 		fdlim_set(maxfd);
802 	fdcon = xcalloc(maxfd, sizeof(con));
803 
804 	read_wait_nfdset = howmany(maxfd, NFDBITS);
805 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
806 
807 	for (j = 0; j < fopt_count; j++) {
808 		if (argv[j] == NULL)
809 			fp = stdin;
810 		else if ((fp = fopen(argv[j], "r")) == NULL)
811 			fatal("%s: %s: %s", __progname, argv[j],
812 			    strerror(errno));
813 		linenum = 0;
814 
815 		while (read_keyfile_line(fp,
816 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
817 		    &linenum) != -1) {
818 			/* Chomp off trailing whitespace and comments */
819 			if ((cp = strchr(line, '#')) == NULL)
820 				cp = line + strlen(line) - 1;
821 			while (cp >= line) {
822 				if (*cp == ' ' || *cp == '\t' ||
823 				    *cp == '\n' || *cp == '#')
824 					*cp-- = '\0';
825 				else
826 					break;
827 			}
828 
829 			/* Skip empty lines */
830 			if (*line == '\0')
831 				continue;
832 
833 			do_host(line);
834 		}
835 
836 		if (ferror(fp))
837 			fatal("%s: %s: %s", __progname, argv[j],
838 			    strerror(errno));
839 
840 		fclose(fp);
841 	}
842 
843 	while (optind < argc)
844 		do_host(argv[optind++]);
845 
846 	while (ncon > 0)
847 		conloop();
848 
849 	return (0);
850 }
851