1 /* $OpenBSD: ssh-keyscan.c,v 1.89 2013/12/06 13:39:49 markus 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 "openbsd-compat/sys-queue.h"
13 #include <sys/resource.h>
14 #ifdef HAVE_SYS_TIME_H
15 # include <sys/time.h>
16 #endif
17 
18 #include <netinet/in.h>
19 #include <arpa/inet.h>
20 
21 #include <openssl/bn.h>
22 
23 #include <netdb.h>
24 #include <errno.h>
25 #include <setjmp.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 "buffer.h"
37 #include "key.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 
49 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
50    Default value is AF_UNSPEC means both IPv4 and IPv6. */
51 int IPv4or6 = AF_UNSPEC;
52 
53 int ssh_port = SSH_DEFAULT_PORT;
54 
55 #define KT_RSA1		1
56 #define KT_DSA		2
57 #define KT_RSA		4
58 #define KT_ECDSA	8
59 #define KT_ED25519	16
60 
61 int get_keytypes = KT_RSA|KT_ECDSA;/* Get RSA and ECDSA keys by default */
62 
63 int hash_hosts = 0;		/* Hash hostname on output */
64 
65 #define MAXMAXFD 256
66 
67 /* The number of seconds after which to give up on a TCP connection */
68 int timeout = 5;
69 
70 int maxfd;
71 #define MAXCON (maxfd - 10)
72 
73 extern char *__progname;
74 fd_set *read_wait;
75 size_t read_wait_nfdset;
76 int ncon;
77 int nonfatal_fatal = 0;
78 jmp_buf kexjmp;
79 Key *kexjmp_key;
80 
81 /*
82  * Keep a connection structure for each file descriptor.  The state
83  * associated with file descriptor n is held in fdcon[n].
84  */
85 typedef struct Connection {
86 	u_char c_status;	/* State of connection on this file desc. */
87 #define CS_UNUSED 0		/* File descriptor unused */
88 #define CS_CON 1		/* Waiting to connect/read greeting */
89 #define CS_SIZE 2		/* Waiting to read initial packet size */
90 #define CS_KEYS 3		/* Waiting to read public key packet */
91 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
92 	int c_plen;		/* Packet length field for ssh packet */
93 	int c_len;		/* Total bytes which must be read. */
94 	int c_off;		/* Length of data read so far. */
95 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
96 	char *c_namebase;	/* Address to free for c_name and c_namelist */
97 	char *c_name;		/* Hostname of connection for errors */
98 	char *c_namelist;	/* Pointer to other possible addresses */
99 	char *c_output_name;	/* Hostname of connection for output */
100 	char *c_data;		/* Data read from this fd */
101 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
102 	struct timeval c_tv;	/* Time at which connection gets aborted */
103 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
104 } con;
105 
106 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
107 con *fdcon;
108 
109 static int
fdlim_get(int hard)110 fdlim_get(int hard)
111 {
112 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
113 	struct rlimit rlfd;
114 
115 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
116 		return (-1);
117 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
118 		return SSH_SYSFDMAX;
119 	else
120 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
121 #else
122 	return SSH_SYSFDMAX;
123 #endif
124 }
125 
126 static int
fdlim_set(int lim)127 fdlim_set(int lim)
128 {
129 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
130 	struct rlimit rlfd;
131 #endif
132 
133 	if (lim <= 0)
134 		return (-1);
135 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
136 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
137 		return (-1);
138 	rlfd.rlim_cur = lim;
139 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
140 		return (-1);
141 #elif defined (HAVE_SETDTABLESIZE)
142 	setdtablesize(lim);
143 #endif
144 	return (0);
145 }
146 
147 /*
148  * This is an strsep function that returns a null field for adjacent
149  * separators.  This is the same as the 4.4BSD strsep, but different from the
150  * one in the GNU libc.
151  */
152 static char *
xstrsep(char ** str,const char * delim)153 xstrsep(char **str, const char *delim)
154 {
155 	char *s, *e;
156 
157 	if (!**str)
158 		return (NULL);
159 
160 	s = *str;
161 	e = s + strcspn(s, delim);
162 
163 	if (*e != '\0')
164 		*e++ = '\0';
165 	*str = e;
166 
167 	return (s);
168 }
169 
170 /*
171  * Get the next non-null token (like GNU strsep).  Strsep() will return a
172  * null token for two adjacent separators, so we may have to loop.
173  */
174 static char *
strnnsep(char ** stringp,char * delim)175 strnnsep(char **stringp, char *delim)
176 {
177 	char *tok;
178 
179 	do {
180 		tok = xstrsep(stringp, delim);
181 	} while (tok && *tok == '\0');
182 	return (tok);
183 }
184 
185 static Key *
keygrab_ssh1(con * c)186 keygrab_ssh1(con *c)
187 {
188 	static Key *rsa;
189 	static Buffer msg;
190 
191 	if (rsa == NULL) {
192 		buffer_init(&msg);
193 		rsa = key_new(KEY_RSA1);
194 	}
195 	buffer_append(&msg, c->c_data, c->c_plen);
196 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
197 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
198 		error("%s: invalid packet type", c->c_name);
199 		buffer_clear(&msg);
200 		return NULL;
201 	}
202 	buffer_consume(&msg, 8);		/* cookie */
203 
204 	/* server key */
205 	(void) buffer_get_int(&msg);
206 	buffer_get_bignum(&msg, rsa->rsa->e);
207 	buffer_get_bignum(&msg, rsa->rsa->n);
208 
209 	/* host key */
210 	(void) buffer_get_int(&msg);
211 	buffer_get_bignum(&msg, rsa->rsa->e);
212 	buffer_get_bignum(&msg, rsa->rsa->n);
213 
214 	buffer_clear(&msg);
215 
216 	return (rsa);
217 }
218 
219 static int
hostjump(Key * hostkey)220 hostjump(Key *hostkey)
221 {
222 	kexjmp_key = hostkey;
223 	longjmp(kexjmp, 1);
224 }
225 
226 static int
ssh2_capable(int remote_major,int remote_minor)227 ssh2_capable(int remote_major, int remote_minor)
228 {
229 	switch (remote_major) {
230 	case 1:
231 		if (remote_minor == 99)
232 			return 1;
233 		break;
234 	case 2:
235 		return 1;
236 	default:
237 		break;
238 	}
239 	return 0;
240 }
241 
242 static Key *
keygrab_ssh2(con * c)243 keygrab_ssh2(con *c)
244 {
245 	int j;
246 
247 	packet_set_connection(c->c_fd, c->c_fd);
248 	enable_compat20();
249 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
250 	    c->c_keytype == KT_DSA ?  "ssh-dss" :
251 	    (c->c_keytype == KT_RSA ? "ssh-rsa" :
252 	    (c->c_keytype == KT_ED25519 ? "ssh-ed25519" :
253 	    "ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521"));
254 	c->c_kex = kex_setup(myproposal);
255 	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
256 	c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
257 	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
258 	c->c_kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
259 	c->c_kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
260 	c->c_kex->kex[KEX_C25519_SHA256] = kexc25519_client;
261 	c->c_kex->verify_host_key = hostjump;
262 
263 	if (!(j = setjmp(kexjmp))) {
264 		nonfatal_fatal = 1;
265 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
266 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
267 		exit(1);
268 	}
269 	nonfatal_fatal = 0;
270 	free(c->c_kex);
271 	c->c_kex = NULL;
272 	packet_close();
273 
274 	return j < 0? NULL : kexjmp_key;
275 }
276 
277 static void
keyprint(con * c,Key * key)278 keyprint(con *c, Key *key)
279 {
280 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
281 
282 	if (!key)
283 		return;
284 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
285 		fatal("host_hash failed");
286 
287 	fprintf(stdout, "%s ", host);
288 	key_write(key, stdout);
289 	fputs("\n", stdout);
290 }
291 
292 static int
tcpconnect(char * host)293 tcpconnect(char *host)
294 {
295 	struct addrinfo hints, *ai, *aitop;
296 	char strport[NI_MAXSERV];
297 	int gaierr, s = -1;
298 
299 	snprintf(strport, sizeof strport, "%d", ssh_port);
300 	memset(&hints, 0, sizeof(hints));
301 	hints.ai_family = IPv4or6;
302 	hints.ai_socktype = SOCK_STREAM;
303 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
304 		fatal("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
305 	for (ai = aitop; ai; ai = ai->ai_next) {
306 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
307 		if (s < 0) {
308 			error("socket: %s", strerror(errno));
309 			continue;
310 		}
311 		if (set_nonblock(s) == -1)
312 			fatal("%s: set_nonblock(%d)", __func__, s);
313 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
314 		    errno != EINPROGRESS)
315 			error("connect (`%s'): %s", host, strerror(errno));
316 		else
317 			break;
318 		close(s);
319 		s = -1;
320 	}
321 	freeaddrinfo(aitop);
322 	return s;
323 }
324 
325 static int
conalloc(char * iname,char * oname,int keytype)326 conalloc(char *iname, char *oname, int keytype)
327 {
328 	char *namebase, *name, *namelist;
329 	int s;
330 
331 	namebase = namelist = xstrdup(iname);
332 
333 	do {
334 		name = xstrsep(&namelist, ",");
335 		if (!name) {
336 			free(namebase);
337 			return (-1);
338 		}
339 	} while ((s = tcpconnect(name)) < 0);
340 
341 	if (s >= maxfd)
342 		fatal("conalloc: fdno %d too high", s);
343 	if (fdcon[s].c_status)
344 		fatal("conalloc: attempt to reuse fdno %d", s);
345 
346 	fdcon[s].c_fd = s;
347 	fdcon[s].c_status = CS_CON;
348 	fdcon[s].c_namebase = namebase;
349 	fdcon[s].c_name = name;
350 	fdcon[s].c_namelist = namelist;
351 	fdcon[s].c_output_name = xstrdup(oname);
352 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
353 	fdcon[s].c_len = 4;
354 	fdcon[s].c_off = 0;
355 	fdcon[s].c_keytype = keytype;
356 	gettimeofday(&fdcon[s].c_tv, NULL);
357 	fdcon[s].c_tv.tv_sec += timeout;
358 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
359 	FD_SET(s, read_wait);
360 	ncon++;
361 	return (s);
362 }
363 
364 static void
confree(int s)365 confree(int s)
366 {
367 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
368 		fatal("confree: attempt to free bad fdno %d", s);
369 	close(s);
370 	free(fdcon[s].c_namebase);
371 	free(fdcon[s].c_output_name);
372 	if (fdcon[s].c_status == CS_KEYS)
373 		free(fdcon[s].c_data);
374 	fdcon[s].c_status = CS_UNUSED;
375 	fdcon[s].c_keytype = 0;
376 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
377 	FD_CLR(s, read_wait);
378 	ncon--;
379 }
380 
381 static void
contouch(int s)382 contouch(int s)
383 {
384 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
385 	gettimeofday(&fdcon[s].c_tv, NULL);
386 	fdcon[s].c_tv.tv_sec += timeout;
387 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
388 }
389 
390 static int
conrecycle(int s)391 conrecycle(int s)
392 {
393 	con *c = &fdcon[s];
394 	int ret;
395 
396 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
397 	confree(s);
398 	return (ret);
399 }
400 
401 static void
congreet(int s)402 congreet(int s)
403 {
404 	int n = 0, remote_major = 0, remote_minor = 0;
405 	char buf[256], *cp;
406 	char remote_version[sizeof buf];
407 	size_t bufsiz;
408 	con *c = &fdcon[s];
409 
410 	for (;;) {
411 		memset(buf, '\0', sizeof(buf));
412 		bufsiz = sizeof(buf);
413 		cp = buf;
414 		while (bufsiz-- &&
415 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
416 			if (*cp == '\r')
417 				*cp = '\n';
418 			cp++;
419 		}
420 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
421 			break;
422 	}
423 	if (n == 0) {
424 		switch (errno) {
425 		case EPIPE:
426 			error("%s: Connection closed by remote host", c->c_name);
427 			break;
428 		case ECONNREFUSED:
429 			break;
430 		default:
431 			error("read (%s): %s", c->c_name, strerror(errno));
432 			break;
433 		}
434 		conrecycle(s);
435 		return;
436 	}
437 	if (*cp != '\n' && *cp != '\r') {
438 		error("%s: bad greeting", c->c_name);
439 		confree(s);
440 		return;
441 	}
442 	*cp = '\0';
443 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
444 	    &remote_major, &remote_minor, remote_version) == 3)
445 		compat_datafellows(remote_version);
446 	else
447 		datafellows = 0;
448 	if (c->c_keytype != KT_RSA1) {
449 		if (!ssh2_capable(remote_major, remote_minor)) {
450 			debug("%s doesn't support ssh2", c->c_name);
451 			confree(s);
452 			return;
453 		}
454 	} else if (remote_major != 1) {
455 		debug("%s doesn't support ssh1", c->c_name);
456 		confree(s);
457 		return;
458 	}
459 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
460 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
461 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
462 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
463 	if (n < 0 || (size_t)n >= sizeof(buf)) {
464 		error("snprintf: buffer too small");
465 		confree(s);
466 		return;
467 	}
468 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
469 		error("write (%s): %s", c->c_name, strerror(errno));
470 		confree(s);
471 		return;
472 	}
473 	if (c->c_keytype != KT_RSA1) {
474 		keyprint(c, keygrab_ssh2(c));
475 		confree(s);
476 		return;
477 	}
478 	c->c_status = CS_SIZE;
479 	contouch(s);
480 }
481 
482 static void
conread(int s)483 conread(int s)
484 {
485 	con *c = &fdcon[s];
486 	size_t n;
487 
488 	if (c->c_status == CS_CON) {
489 		congreet(s);
490 		return;
491 	}
492 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
493 	if (n == 0) {
494 		error("read (%s): %s", c->c_name, strerror(errno));
495 		confree(s);
496 		return;
497 	}
498 	c->c_off += n;
499 
500 	if (c->c_off == c->c_len)
501 		switch (c->c_status) {
502 		case CS_SIZE:
503 			c->c_plen = htonl(c->c_plen);
504 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
505 			c->c_off = 0;
506 			c->c_data = xmalloc(c->c_len);
507 			c->c_status = CS_KEYS;
508 			break;
509 		case CS_KEYS:
510 			keyprint(c, keygrab_ssh1(c));
511 			confree(s);
512 			return;
513 		default:
514 			fatal("conread: invalid status %d", c->c_status);
515 			break;
516 		}
517 
518 	contouch(s);
519 }
520 
521 static void
conloop(void)522 conloop(void)
523 {
524 	struct timeval seltime, now;
525 	fd_set *r, *e;
526 	con *c;
527 	int i;
528 
529 	gettimeofday(&now, NULL);
530 	c = TAILQ_FIRST(&tq);
531 
532 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
533 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
534 		seltime = c->c_tv;
535 		seltime.tv_sec -= now.tv_sec;
536 		seltime.tv_usec -= now.tv_usec;
537 		if (seltime.tv_usec < 0) {
538 			seltime.tv_usec += 1000000;
539 			seltime.tv_sec--;
540 		}
541 	} else
542 		timerclear(&seltime);
543 
544 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
545 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
546 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
547 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
548 
549 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
550 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
551 		;
552 
553 	for (i = 0; i < maxfd; i++) {
554 		if (FD_ISSET(i, e)) {
555 			error("%s: exception!", fdcon[i].c_name);
556 			confree(i);
557 		} else if (FD_ISSET(i, r))
558 			conread(i);
559 	}
560 	free(r);
561 	free(e);
562 
563 	c = TAILQ_FIRST(&tq);
564 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
565 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
566 		int s = c->c_fd;
567 
568 		c = TAILQ_NEXT(c, c_link);
569 		conrecycle(s);
570 	}
571 }
572 
573 static void
do_host(char * host)574 do_host(char *host)
575 {
576 	char *name = strnnsep(&host, " \t\n");
577 	int j;
578 
579 	if (name == NULL)
580 		return;
581 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
582 		if (get_keytypes & j) {
583 			while (ncon >= MAXCON)
584 				conloop();
585 			conalloc(name, *host ? host : name, j);
586 		}
587 	}
588 }
589 
590 void
fatal(const char * fmt,...)591 fatal(const char *fmt,...)
592 {
593 	va_list args;
594 
595 	va_start(args, fmt);
596 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
597 	va_end(args);
598 	if (nonfatal_fatal)
599 		longjmp(kexjmp, -1);
600 	else
601 		exit(255);
602 }
603 
604 static void
usage(void)605 usage(void)
606 {
607 	fprintf(stderr,
608 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
609 	    "\t\t   [host | addrlist namelist] ...\n",
610 	    __progname);
611 	exit(1);
612 }
613 
614 int
main(int argc,char ** argv)615 main(int argc, char **argv)
616 {
617 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
618 	int opt, fopt_count = 0, j;
619 	char *tname, *cp, line[NI_MAXHOST];
620 	FILE *fp;
621 	u_long linenum;
622 
623 	extern int optind;
624 	extern char *optarg;
625 
626 	__progname = ssh_get_progname(argv[0]);
627 	seed_rng();
628 	TAILQ_INIT(&tq);
629 
630 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
631 	sanitise_stdfd();
632 
633 	if (argc <= 1)
634 		usage();
635 
636 	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
637 		switch (opt) {
638 		case 'H':
639 			hash_hosts = 1;
640 			break;
641 		case 'p':
642 			ssh_port = a2port(optarg);
643 			if (ssh_port <= 0) {
644 				fprintf(stderr, "Bad port '%s'\n", optarg);
645 				exit(1);
646 			}
647 			break;
648 		case 'T':
649 			timeout = convtime(optarg);
650 			if (timeout == -1 || timeout == 0) {
651 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
652 				usage();
653 			}
654 			break;
655 		case 'v':
656 			if (!debug_flag) {
657 				debug_flag = 1;
658 				log_level = SYSLOG_LEVEL_DEBUG1;
659 			}
660 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
661 				log_level++;
662 			else
663 				fatal("Too high debugging level.");
664 			break;
665 		case 'f':
666 			if (strcmp(optarg, "-") == 0)
667 				optarg = NULL;
668 			argv[fopt_count++] = optarg;
669 			break;
670 		case 't':
671 			get_keytypes = 0;
672 			tname = strtok(optarg, ",");
673 			while (tname) {
674 				int type = key_type_from_name(tname);
675 				switch (type) {
676 				case KEY_RSA1:
677 					get_keytypes |= KT_RSA1;
678 					break;
679 				case KEY_DSA:
680 					get_keytypes |= KT_DSA;
681 					break;
682 				case KEY_ECDSA:
683 					get_keytypes |= KT_ECDSA;
684 					break;
685 				case KEY_RSA:
686 					get_keytypes |= KT_RSA;
687 					break;
688 				case KEY_ED25519:
689 					get_keytypes |= KT_ED25519;
690 					break;
691 				case KEY_UNSPEC:
692 					fatal("unknown key type %s", tname);
693 				}
694 				tname = strtok(NULL, ",");
695 			}
696 			break;
697 		case '4':
698 			IPv4or6 = AF_INET;
699 			break;
700 		case '6':
701 			IPv4or6 = AF_INET6;
702 			break;
703 		case '?':
704 		default:
705 			usage();
706 		}
707 	}
708 	if (optind == argc && !fopt_count)
709 		usage();
710 
711 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
712 
713 	maxfd = fdlim_get(1);
714 	if (maxfd < 0)
715 		fatal("%s: fdlim_get: bad value", __progname);
716 	if (maxfd > MAXMAXFD)
717 		maxfd = MAXMAXFD;
718 	if (MAXCON <= 0)
719 		fatal("%s: not enough file descriptors", __progname);
720 	if (maxfd > fdlim_get(0))
721 		fdlim_set(maxfd);
722 	fdcon = xcalloc(maxfd, sizeof(con));
723 
724 	read_wait_nfdset = howmany(maxfd, NFDBITS);
725 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
726 
727 	for (j = 0; j < fopt_count; j++) {
728 		if (argv[j] == NULL)
729 			fp = stdin;
730 		else if ((fp = fopen(argv[j], "r")) == NULL)
731 			fatal("%s: %s: %s", __progname, argv[j],
732 			    strerror(errno));
733 		linenum = 0;
734 
735 		while (read_keyfile_line(fp,
736 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
737 		    &linenum) != -1) {
738 			/* Chomp off trailing whitespace and comments */
739 			if ((cp = strchr(line, '#')) == NULL)
740 				cp = line + strlen(line) - 1;
741 			while (cp >= line) {
742 				if (*cp == ' ' || *cp == '\t' ||
743 				    *cp == '\n' || *cp == '#')
744 					*cp-- = '\0';
745 				else
746 					break;
747 			}
748 
749 			/* Skip empty lines */
750 			if (*line == '\0')
751 				continue;
752 
753 			do_host(line);
754 		}
755 
756 		if (ferror(fp))
757 			fatal("%s: %s: %s", __progname, argv[j],
758 			    strerror(errno));
759 
760 		fclose(fp);
761 	}
762 
763 	while (optind < argc)
764 		do_host(argv[optind++]);
765 
766 	while (ncon > 0)
767 		conloop();
768 
769 	return (0);
770 }
771