xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision ea825d02749f382c3f7e17f28247f20a48733eab)
1 /* $OpenBSD: ssh-keyscan.c,v 1.109 2017/03/10 04:26:06 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(const char *host, struct sshkey *key)
325 {
326 	char *hostport;
327 	const char *known_host, *hashed;
328 
329 	hostport = put_host_port(host, ssh_port);
330 	lowercase(hostport);
331 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
332 		fatal("host_hash failed");
333 	known_host = hash_hosts ? hashed : hostport;
334 	if (!get_cert)
335 		fprintf(stdout, "%s ", known_host);
336 	sshkey_write(key, stdout);
337 	fputs("\n", stdout);
338 	free(hostport);
339 }
340 
341 static void
342 keyprint(con *c, struct sshkey *key)
343 {
344 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
345 	char *host, *ohosts;
346 
347 	if (key == NULL)
348 		return;
349 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
350 		keyprint_one(hosts, key);
351 		return;
352 	}
353 	ohosts = hosts = xstrdup(hosts);
354 	while ((host = strsep(&hosts, ",")) != NULL)
355 		keyprint_one(host, key);
356 	free(ohosts);
357 }
358 
359 static int
360 tcpconnect(char *host)
361 {
362 	struct addrinfo hints, *ai, *aitop;
363 	char strport[NI_MAXSERV];
364 	int gaierr, s = -1;
365 
366 	snprintf(strport, sizeof strport, "%d", ssh_port);
367 	memset(&hints, 0, sizeof(hints));
368 	hints.ai_family = IPv4or6;
369 	hints.ai_socktype = SOCK_STREAM;
370 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
371 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
372 		return -1;
373 	}
374 	for (ai = aitop; ai; ai = ai->ai_next) {
375 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
376 		if (s < 0) {
377 			error("socket: %s", strerror(errno));
378 			continue;
379 		}
380 		if (set_nonblock(s) == -1)
381 			fatal("%s: set_nonblock(%d)", __func__, s);
382 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
383 		    errno != EINPROGRESS)
384 			error("connect (`%s'): %s", host, strerror(errno));
385 		else
386 			break;
387 		close(s);
388 		s = -1;
389 	}
390 	freeaddrinfo(aitop);
391 	return s;
392 }
393 
394 static int
395 conalloc(char *iname, char *oname, int keytype)
396 {
397 	char *namebase, *name, *namelist;
398 	int s;
399 
400 	namebase = namelist = xstrdup(iname);
401 
402 	do {
403 		name = xstrsep(&namelist, ",");
404 		if (!name) {
405 			free(namebase);
406 			return (-1);
407 		}
408 	} while ((s = tcpconnect(name)) < 0);
409 
410 	if (s >= maxfd)
411 		fatal("conalloc: fdno %d too high", s);
412 	if (fdcon[s].c_status)
413 		fatal("conalloc: attempt to reuse fdno %d", s);
414 
415 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
416 	fdcon[s].c_fd = s;
417 	fdcon[s].c_status = CS_CON;
418 	fdcon[s].c_namebase = namebase;
419 	fdcon[s].c_name = name;
420 	fdcon[s].c_namelist = namelist;
421 	fdcon[s].c_output_name = xstrdup(oname);
422 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
423 	fdcon[s].c_len = 4;
424 	fdcon[s].c_off = 0;
425 	fdcon[s].c_keytype = keytype;
426 	gettimeofday(&fdcon[s].c_tv, NULL);
427 	fdcon[s].c_tv.tv_sec += timeout;
428 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
429 	FD_SET(s, read_wait);
430 	ncon++;
431 	return (s);
432 }
433 
434 static void
435 confree(int s)
436 {
437 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
438 		fatal("confree: attempt to free bad fdno %d", s);
439 	close(s);
440 	free(fdcon[s].c_namebase);
441 	free(fdcon[s].c_output_name);
442 	if (fdcon[s].c_status == CS_KEYS)
443 		free(fdcon[s].c_data);
444 	fdcon[s].c_status = CS_UNUSED;
445 	fdcon[s].c_keytype = 0;
446 	if (fdcon[s].c_ssh) {
447 		ssh_packet_close(fdcon[s].c_ssh);
448 		free(fdcon[s].c_ssh);
449 		fdcon[s].c_ssh = NULL;
450 	}
451 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
452 	FD_CLR(s, read_wait);
453 	ncon--;
454 }
455 
456 static void
457 contouch(int s)
458 {
459 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
460 	gettimeofday(&fdcon[s].c_tv, NULL);
461 	fdcon[s].c_tv.tv_sec += timeout;
462 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
463 }
464 
465 static int
466 conrecycle(int s)
467 {
468 	con *c = &fdcon[s];
469 	int ret;
470 
471 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
472 	confree(s);
473 	return (ret);
474 }
475 
476 static void
477 congreet(int s)
478 {
479 	int n = 0, remote_major = 0, remote_minor = 0;
480 	char buf[256], *cp;
481 	char remote_version[sizeof buf];
482 	size_t bufsiz;
483 	con *c = &fdcon[s];
484 
485 	for (;;) {
486 		memset(buf, '\0', sizeof(buf));
487 		bufsiz = sizeof(buf);
488 		cp = buf;
489 		while (bufsiz-- &&
490 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
491 			if (*cp == '\r')
492 				*cp = '\n';
493 			cp++;
494 		}
495 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
496 			break;
497 	}
498 	if (n == 0) {
499 		switch (errno) {
500 		case EPIPE:
501 			error("%s: Connection closed by remote host", c->c_name);
502 			break;
503 		case ECONNREFUSED:
504 			break;
505 		default:
506 			error("read (%s): %s", c->c_name, strerror(errno));
507 			break;
508 		}
509 		conrecycle(s);
510 		return;
511 	}
512 	if (*cp != '\n' && *cp != '\r') {
513 		error("%s: bad greeting", c->c_name);
514 		confree(s);
515 		return;
516 	}
517 	*cp = '\0';
518 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
519 		fatal("ssh_packet_set_connection failed");
520 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
521 	ssh_set_app_data(c->c_ssh, c);	/* back link */
522 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
523 	    &remote_major, &remote_minor, remote_version) == 3)
524 		c->c_ssh->compat = compat_datafellows(remote_version);
525 	else
526 		c->c_ssh->compat = 0;
527 	if (c->c_keytype != KT_RSA1) {
528 		if (!ssh2_capable(remote_major, remote_minor)) {
529 			debug("%s doesn't support ssh2", c->c_name);
530 			confree(s);
531 			return;
532 		}
533 	} else if (remote_major != 1) {
534 		debug("%s doesn't support ssh1", c->c_name);
535 		confree(s);
536 		return;
537 	}
538 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
539 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
540 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
541 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
542 	if (n < 0 || (size_t)n >= sizeof(buf)) {
543 		error("snprintf: buffer too small");
544 		confree(s);
545 		return;
546 	}
547 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
548 		error("write (%s): %s", c->c_name, strerror(errno));
549 		confree(s);
550 		return;
551 	}
552 	if (c->c_keytype != KT_RSA1) {
553 		keygrab_ssh2(c);
554 		confree(s);
555 		return;
556 	}
557 	c->c_status = CS_SIZE;
558 	contouch(s);
559 }
560 
561 static void
562 conread(int s)
563 {
564 	con *c = &fdcon[s];
565 	size_t n;
566 
567 	if (c->c_status == CS_CON) {
568 		congreet(s);
569 		return;
570 	}
571 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
572 	if (n == 0) {
573 		error("read (%s): %s", c->c_name, strerror(errno));
574 		confree(s);
575 		return;
576 	}
577 	c->c_off += n;
578 
579 	if (c->c_off == c->c_len)
580 		switch (c->c_status) {
581 		case CS_SIZE:
582 			c->c_plen = htonl(c->c_plen);
583 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
584 			c->c_off = 0;
585 			c->c_data = xmalloc(c->c_len);
586 			c->c_status = CS_KEYS;
587 			break;
588 #ifdef WITH_SSH1
589 		case CS_KEYS:
590 			keyprint(c, keygrab_ssh1(c));
591 			confree(s);
592 			return;
593 #endif
594 		default:
595 			fatal("conread: invalid status %d", c->c_status);
596 			break;
597 		}
598 
599 	contouch(s);
600 }
601 
602 static void
603 conloop(void)
604 {
605 	struct timeval seltime, now;
606 	fd_set *r, *e;
607 	con *c;
608 	int i;
609 
610 	gettimeofday(&now, NULL);
611 	c = TAILQ_FIRST(&tq);
612 
613 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
614 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
615 		seltime = c->c_tv;
616 		seltime.tv_sec -= now.tv_sec;
617 		seltime.tv_usec -= now.tv_usec;
618 		if (seltime.tv_usec < 0) {
619 			seltime.tv_usec += 1000000;
620 			seltime.tv_sec--;
621 		}
622 	} else
623 		timerclear(&seltime);
624 
625 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
626 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
627 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
628 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
629 
630 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
631 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
632 		;
633 
634 	for (i = 0; i < maxfd; i++) {
635 		if (FD_ISSET(i, e)) {
636 			error("%s: exception!", fdcon[i].c_name);
637 			confree(i);
638 		} else if (FD_ISSET(i, r))
639 			conread(i);
640 	}
641 	free(r);
642 	free(e);
643 
644 	c = TAILQ_FIRST(&tq);
645 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
646 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
647 		int s = c->c_fd;
648 
649 		c = TAILQ_NEXT(c, c_link);
650 		conrecycle(s);
651 	}
652 }
653 
654 static void
655 do_host(char *host)
656 {
657 	char *name = strnnsep(&host, " \t\n");
658 	int j;
659 
660 	if (name == NULL)
661 		return;
662 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
663 		if (get_keytypes & j) {
664 			while (ncon >= MAXCON)
665 				conloop();
666 			conalloc(name, *host ? host : name, j);
667 		}
668 	}
669 }
670 
671 void
672 fatal(const char *fmt,...)
673 {
674 	va_list args;
675 
676 	va_start(args, fmt);
677 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
678 	va_end(args);
679 	exit(255);
680 }
681 
682 static void
683 usage(void)
684 {
685 	fprintf(stderr,
686 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
687 	    "\t\t   [host | addrlist namelist] ...\n",
688 	    __progname);
689 	exit(1);
690 }
691 
692 int
693 main(int argc, char **argv)
694 {
695 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
696 	int opt, fopt_count = 0, j;
697 	char *tname, *cp, line[NI_MAXHOST];
698 	FILE *fp;
699 	u_long linenum;
700 
701 	extern int optind;
702 	extern char *optarg;
703 
704 	ssh_malloc_init();	/* must be called before any mallocs */
705 	__progname = ssh_get_progname(argv[0]);
706 	seed_rng();
707 	TAILQ_INIT(&tq);
708 
709 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
710 	sanitise_stdfd();
711 
712 	if (argc <= 1)
713 		usage();
714 
715 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
716 		switch (opt) {
717 		case 'H':
718 			hash_hosts = 1;
719 			break;
720 		case 'c':
721 			get_cert = 1;
722 			break;
723 		case 'p':
724 			ssh_port = a2port(optarg);
725 			if (ssh_port <= 0) {
726 				fprintf(stderr, "Bad port '%s'\n", optarg);
727 				exit(1);
728 			}
729 			break;
730 		case 'T':
731 			timeout = convtime(optarg);
732 			if (timeout == -1 || timeout == 0) {
733 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
734 				usage();
735 			}
736 			break;
737 		case 'v':
738 			if (!debug_flag) {
739 				debug_flag = 1;
740 				log_level = SYSLOG_LEVEL_DEBUG1;
741 			}
742 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
743 				log_level++;
744 			else
745 				fatal("Too high debugging level.");
746 			break;
747 		case 'f':
748 			if (strcmp(optarg, "-") == 0)
749 				optarg = NULL;
750 			argv[fopt_count++] = optarg;
751 			break;
752 		case 't':
753 			get_keytypes = 0;
754 			tname = strtok(optarg, ",");
755 			while (tname) {
756 				int type = sshkey_type_from_name(tname);
757 
758 				switch (type) {
759 #ifdef WITH_SSH1
760 				case KEY_RSA1:
761 					get_keytypes |= KT_RSA1;
762 					break;
763 #endif
764 				case KEY_DSA:
765 					get_keytypes |= KT_DSA;
766 					break;
767 				case KEY_ECDSA:
768 					get_keytypes |= KT_ECDSA;
769 					break;
770 				case KEY_RSA:
771 					get_keytypes |= KT_RSA;
772 					break;
773 				case KEY_ED25519:
774 					get_keytypes |= KT_ED25519;
775 					break;
776 				case KEY_UNSPEC:
777 				default:
778 					fatal("Unknown key type \"%s\"", tname);
779 				}
780 				tname = strtok(NULL, ",");
781 			}
782 			break;
783 		case '4':
784 			IPv4or6 = AF_INET;
785 			break;
786 		case '6':
787 			IPv4or6 = AF_INET6;
788 			break;
789 		case '?':
790 		default:
791 			usage();
792 		}
793 	}
794 	if (optind == argc && !fopt_count)
795 		usage();
796 
797 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
798 
799 	maxfd = fdlim_get(1);
800 	if (maxfd < 0)
801 		fatal("%s: fdlim_get: bad value", __progname);
802 	if (maxfd > MAXMAXFD)
803 		maxfd = MAXMAXFD;
804 	if (MAXCON <= 0)
805 		fatal("%s: not enough file descriptors", __progname);
806 	if (maxfd > fdlim_get(0))
807 		fdlim_set(maxfd);
808 	fdcon = xcalloc(maxfd, sizeof(con));
809 
810 	read_wait_nfdset = howmany(maxfd, NFDBITS);
811 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
812 
813 	for (j = 0; j < fopt_count; j++) {
814 		if (argv[j] == NULL)
815 			fp = stdin;
816 		else if ((fp = fopen(argv[j], "r")) == NULL)
817 			fatal("%s: %s: %s", __progname, argv[j],
818 			    strerror(errno));
819 		linenum = 0;
820 
821 		while (read_keyfile_line(fp,
822 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
823 		    &linenum) != -1) {
824 			/* Chomp off trailing whitespace and comments */
825 			if ((cp = strchr(line, '#')) == NULL)
826 				cp = line + strlen(line) - 1;
827 			while (cp >= line) {
828 				if (*cp == ' ' || *cp == '\t' ||
829 				    *cp == '\n' || *cp == '#')
830 					*cp-- = '\0';
831 				else
832 					break;
833 			}
834 
835 			/* Skip empty lines */
836 			if (*line == '\0')
837 				continue;
838 
839 			do_host(line);
840 		}
841 
842 		if (ferror(fp))
843 			fatal("%s: %s: %s", __progname, argv[j],
844 			    strerror(errno));
845 
846 		fclose(fp);
847 	}
848 
849 	while (optind < argc)
850 		do_host(argv[optind++]);
851 
852 	while (ncon > 0)
853 		conloop();
854 
855 	return (0);
856 }
857