xref: /openbsd-src/usr.bin/ssh/ssh-keyscan.c (revision a28daedfc357b214be5c701aa8ba8adb29a7f1c2)
1 /* $OpenBSD: ssh-keyscan.c,v 1.78 2009/01/22 10:02:34 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 <sys/types.h>
11 #include <sys/socket.h>
12 #include <sys/queue.h>
13 #include <sys/time.h>
14 #include <sys/resource.h>
15 
16 #include <openssl/bn.h>
17 
18 #include <errno.h>
19 #include <netdb.h>
20 #include <setjmp.h>
21 #include <stdarg.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <signal.h>
25 #include <string.h>
26 #include <unistd.h>
27 
28 #include "xmalloc.h"
29 #include "ssh.h"
30 #include "ssh1.h"
31 #include "buffer.h"
32 #include "key.h"
33 #include "cipher.h"
34 #include "kex.h"
35 #include "compat.h"
36 #include "myproposal.h"
37 #include "packet.h"
38 #include "dispatch.h"
39 #include "log.h"
40 #include "atomicio.h"
41 #include "misc.h"
42 #include "hostfile.h"
43 
44 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
45    Default value is AF_UNSPEC means both IPv4 and IPv6. */
46 int IPv4or6 = AF_UNSPEC;
47 
48 int ssh_port = SSH_DEFAULT_PORT;
49 
50 #define KT_RSA1	1
51 #define KT_DSA	2
52 #define KT_RSA	4
53 
54 int get_keytypes = KT_RSA;	/* Get only RSA keys by default */
55 
56 int hash_hosts = 0;		/* Hash hostname on output */
57 
58 #define MAXMAXFD 256
59 
60 /* The number of seconds after which to give up on a TCP connection */
61 int timeout = 5;
62 
63 int maxfd;
64 #define MAXCON (maxfd - 10)
65 
66 extern char *__progname;
67 fd_set *read_wait;
68 size_t read_wait_nfdset;
69 int ncon;
70 int nonfatal_fatal = 0;
71 jmp_buf kexjmp;
72 Key *kexjmp_key;
73 
74 /*
75  * Keep a connection structure for each file descriptor.  The state
76  * associated with file descriptor n is held in fdcon[n].
77  */
78 typedef struct Connection {
79 	u_char c_status;	/* State of connection on this file desc. */
80 #define CS_UNUSED 0		/* File descriptor unused */
81 #define CS_CON 1		/* Waiting to connect/read greeting */
82 #define CS_SIZE 2		/* Waiting to read initial packet size */
83 #define CS_KEYS 3		/* Waiting to read public key packet */
84 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
85 	int c_plen;		/* Packet length field for ssh packet */
86 	int c_len;		/* Total bytes which must be read. */
87 	int c_off;		/* Length of data read so far. */
88 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
89 	char *c_namebase;	/* Address to free for c_name and c_namelist */
90 	char *c_name;		/* Hostname of connection for errors */
91 	char *c_namelist;	/* Pointer to other possible addresses */
92 	char *c_output_name;	/* Hostname of connection for output */
93 	char *c_data;		/* Data read from this fd */
94 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
95 	struct timeval c_tv;	/* Time at which connection gets aborted */
96 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
97 } con;
98 
99 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
100 con *fdcon;
101 
102 /*
103  *  This is just a wrapper around fgets() to make it usable.
104  */
105 
106 /* Stress-test.  Increase this later. */
107 #define LINEBUF_SIZE 16
108 
109 typedef struct {
110 	char *buf;
111 	u_int size;
112 	int lineno;
113 	const char *filename;
114 	FILE *stream;
115 	void (*errfun) (const char *,...);
116 } Linebuf;
117 
118 static Linebuf *
119 Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
120 {
121 	Linebuf *lb;
122 
123 	if (!(lb = malloc(sizeof(*lb)))) {
124 		if (errfun)
125 			(*errfun) ("linebuf (%s): malloc failed\n",
126 			    filename ? filename : "(stdin)");
127 		return (NULL);
128 	}
129 	if (filename) {
130 		lb->filename = filename;
131 		if (!(lb->stream = fopen(filename, "r"))) {
132 			xfree(lb);
133 			if (errfun)
134 				(*errfun) ("%s: %s\n", filename, strerror(errno));
135 			return (NULL);
136 		}
137 	} else {
138 		lb->filename = "(stdin)";
139 		lb->stream = stdin;
140 	}
141 
142 	if (!(lb->buf = malloc((lb->size = LINEBUF_SIZE)))) {
143 		if (errfun)
144 			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
145 		xfree(lb);
146 		return (NULL);
147 	}
148 	lb->errfun = errfun;
149 	lb->lineno = 0;
150 	return (lb);
151 }
152 
153 static void
154 Linebuf_free(Linebuf * lb)
155 {
156 	fclose(lb->stream);
157 	xfree(lb->buf);
158 	xfree(lb);
159 }
160 
161 #if 0
162 static void
163 Linebuf_restart(Linebuf * lb)
164 {
165 	clearerr(lb->stream);
166 	rewind(lb->stream);
167 	lb->lineno = 0;
168 }
169 
170 static int
171 Linebuf_lineno(Linebuf * lb)
172 {
173 	return (lb->lineno);
174 }
175 #endif
176 
177 static char *
178 Linebuf_getline(Linebuf * lb)
179 {
180 	size_t n = 0;
181 	void *p;
182 
183 	lb->lineno++;
184 	for (;;) {
185 		/* Read a line */
186 		if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
187 			if (ferror(lb->stream) && lb->errfun)
188 				(*lb->errfun)("%s: %s\n", lb->filename,
189 				    strerror(errno));
190 			return (NULL);
191 		}
192 		n = strlen(lb->buf);
193 
194 		/* Return it or an error if it fits */
195 		if (n > 0 && lb->buf[n - 1] == '\n') {
196 			lb->buf[n - 1] = '\0';
197 			return (lb->buf);
198 		}
199 		if (n != lb->size - 1) {
200 			if (lb->errfun)
201 				(*lb->errfun)("%s: skipping incomplete last line\n",
202 				    lb->filename);
203 			return (NULL);
204 		}
205 		/* Double the buffer if we need more space */
206 		lb->size *= 2;
207 		if ((p = realloc(lb->buf, lb->size)) == NULL) {
208 			lb->size /= 2;
209 			if (lb->errfun)
210 				(*lb->errfun)("linebuf (%s): realloc failed\n",
211 				    lb->filename);
212 			return (NULL);
213 		}
214 		lb->buf = p;
215 	}
216 }
217 
218 static int
219 fdlim_get(int hard)
220 {
221 	struct rlimit rlfd;
222 
223 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
224 		return (-1);
225 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
226 		return sysconf(_SC_OPEN_MAX);
227 	else
228 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
229 }
230 
231 static int
232 fdlim_set(int lim)
233 {
234 	struct rlimit rlfd;
235 
236 	if (lim <= 0)
237 		return (-1);
238 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
239 		return (-1);
240 	rlfd.rlim_cur = lim;
241 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
242 		return (-1);
243 	return (0);
244 }
245 
246 /*
247  * This is an strsep function that returns a null field for adjacent
248  * separators.  This is the same as the 4.4BSD strsep, but different from the
249  * one in the GNU libc.
250  */
251 static char *
252 xstrsep(char **str, const char *delim)
253 {
254 	char *s, *e;
255 
256 	if (!**str)
257 		return (NULL);
258 
259 	s = *str;
260 	e = s + strcspn(s, delim);
261 
262 	if (*e != '\0')
263 		*e++ = '\0';
264 	*str = e;
265 
266 	return (s);
267 }
268 
269 /*
270  * Get the next non-null token (like GNU strsep).  Strsep() will return a
271  * null token for two adjacent separators, so we may have to loop.
272  */
273 static char *
274 strnnsep(char **stringp, char *delim)
275 {
276 	char *tok;
277 
278 	do {
279 		tok = xstrsep(stringp, delim);
280 	} while (tok && *tok == '\0');
281 	return (tok);
282 }
283 
284 static Key *
285 keygrab_ssh1(con *c)
286 {
287 	static Key *rsa;
288 	static Buffer msg;
289 
290 	if (rsa == NULL) {
291 		buffer_init(&msg);
292 		rsa = key_new(KEY_RSA1);
293 	}
294 	buffer_append(&msg, c->c_data, c->c_plen);
295 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
296 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
297 		error("%s: invalid packet type", c->c_name);
298 		buffer_clear(&msg);
299 		return NULL;
300 	}
301 	buffer_consume(&msg, 8);		/* cookie */
302 
303 	/* server key */
304 	(void) buffer_get_int(&msg);
305 	buffer_get_bignum(&msg, rsa->rsa->e);
306 	buffer_get_bignum(&msg, rsa->rsa->n);
307 
308 	/* host key */
309 	(void) buffer_get_int(&msg);
310 	buffer_get_bignum(&msg, rsa->rsa->e);
311 	buffer_get_bignum(&msg, rsa->rsa->n);
312 
313 	buffer_clear(&msg);
314 
315 	return (rsa);
316 }
317 
318 static int
319 hostjump(Key *hostkey)
320 {
321 	kexjmp_key = hostkey;
322 	longjmp(kexjmp, 1);
323 }
324 
325 static int
326 ssh2_capable(int remote_major, int remote_minor)
327 {
328 	switch (remote_major) {
329 	case 1:
330 		if (remote_minor == 99)
331 			return 1;
332 		break;
333 	case 2:
334 		return 1;
335 	default:
336 		break;
337 	}
338 	return 0;
339 }
340 
341 static Key *
342 keygrab_ssh2(con *c)
343 {
344 	int j;
345 
346 	packet_set_connection(c->c_fd, c->c_fd);
347 	enable_compat20();
348 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
349 	    "ssh-dss": "ssh-rsa";
350 	c->c_kex = kex_setup(myproposal);
351 	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
352 	c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
353 	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
354 	c->c_kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
355 	c->c_kex->verify_host_key = hostjump;
356 
357 	if (!(j = setjmp(kexjmp))) {
358 		nonfatal_fatal = 1;
359 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
360 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
361 		exit(1);
362 	}
363 	nonfatal_fatal = 0;
364 	xfree(c->c_kex);
365 	c->c_kex = NULL;
366 	packet_close();
367 
368 	return j < 0? NULL : kexjmp_key;
369 }
370 
371 static void
372 keyprint(con *c, Key *key)
373 {
374 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
375 
376 	if (!key)
377 		return;
378 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
379 		fatal("host_hash failed");
380 
381 	fprintf(stdout, "%s ", host);
382 	key_write(key, stdout);
383 	fputs("\n", stdout);
384 }
385 
386 static int
387 tcpconnect(char *host)
388 {
389 	struct addrinfo hints, *ai, *aitop;
390 	char strport[NI_MAXSERV];
391 	int gaierr, s = -1;
392 
393 	snprintf(strport, sizeof strport, "%d", ssh_port);
394 	memset(&hints, 0, sizeof(hints));
395 	hints.ai_family = IPv4or6;
396 	hints.ai_socktype = SOCK_STREAM;
397 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
398 		fatal("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
399 	for (ai = aitop; ai; ai = ai->ai_next) {
400 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
401 		if (s < 0) {
402 			error("socket: %s", strerror(errno));
403 			continue;
404 		}
405 		if (set_nonblock(s) == -1)
406 			fatal("%s: set_nonblock(%d)", __func__, s);
407 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
408 		    errno != EINPROGRESS)
409 			error("connect (`%s'): %s", host, strerror(errno));
410 		else
411 			break;
412 		close(s);
413 		s = -1;
414 	}
415 	freeaddrinfo(aitop);
416 	return s;
417 }
418 
419 static int
420 conalloc(char *iname, char *oname, int keytype)
421 {
422 	char *namebase, *name, *namelist;
423 	int s;
424 
425 	namebase = namelist = xstrdup(iname);
426 
427 	do {
428 		name = xstrsep(&namelist, ",");
429 		if (!name) {
430 			xfree(namebase);
431 			return (-1);
432 		}
433 	} while ((s = tcpconnect(name)) < 0);
434 
435 	if (s >= maxfd)
436 		fatal("conalloc: fdno %d too high", s);
437 	if (fdcon[s].c_status)
438 		fatal("conalloc: attempt to reuse fdno %d", s);
439 
440 	fdcon[s].c_fd = s;
441 	fdcon[s].c_status = CS_CON;
442 	fdcon[s].c_namebase = namebase;
443 	fdcon[s].c_name = name;
444 	fdcon[s].c_namelist = namelist;
445 	fdcon[s].c_output_name = xstrdup(oname);
446 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
447 	fdcon[s].c_len = 4;
448 	fdcon[s].c_off = 0;
449 	fdcon[s].c_keytype = keytype;
450 	gettimeofday(&fdcon[s].c_tv, NULL);
451 	fdcon[s].c_tv.tv_sec += timeout;
452 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
453 	FD_SET(s, read_wait);
454 	ncon++;
455 	return (s);
456 }
457 
458 static void
459 confree(int s)
460 {
461 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
462 		fatal("confree: attempt to free bad fdno %d", s);
463 	close(s);
464 	xfree(fdcon[s].c_namebase);
465 	xfree(fdcon[s].c_output_name);
466 	if (fdcon[s].c_status == CS_KEYS)
467 		xfree(fdcon[s].c_data);
468 	fdcon[s].c_status = CS_UNUSED;
469 	fdcon[s].c_keytype = 0;
470 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
471 	FD_CLR(s, read_wait);
472 	ncon--;
473 }
474 
475 static void
476 contouch(int s)
477 {
478 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
479 	gettimeofday(&fdcon[s].c_tv, NULL);
480 	fdcon[s].c_tv.tv_sec += timeout;
481 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
482 }
483 
484 static int
485 conrecycle(int s)
486 {
487 	con *c = &fdcon[s];
488 	int ret;
489 
490 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
491 	confree(s);
492 	return (ret);
493 }
494 
495 static void
496 congreet(int s)
497 {
498 	int n = 0, remote_major = 0, remote_minor = 0;
499 	char buf[256], *cp;
500 	char remote_version[sizeof buf];
501 	size_t bufsiz;
502 	con *c = &fdcon[s];
503 
504 	for (;;) {
505 		memset(buf, '\0', sizeof(buf));
506 		bufsiz = sizeof(buf);
507 		cp = buf;
508 		while (bufsiz-- &&
509 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
510 			if (*cp == '\r')
511 				*cp = '\n';
512 			cp++;
513 		}
514 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
515 			break;
516 	}
517 	if (n == 0) {
518 		switch (errno) {
519 		case EPIPE:
520 			error("%s: Connection closed by remote host", c->c_name);
521 			break;
522 		case ECONNREFUSED:
523 			break;
524 		default:
525 			error("read (%s): %s", c->c_name, strerror(errno));
526 			break;
527 		}
528 		conrecycle(s);
529 		return;
530 	}
531 	if (*cp != '\n' && *cp != '\r') {
532 		error("%s: bad greeting", c->c_name);
533 		confree(s);
534 		return;
535 	}
536 	*cp = '\0';
537 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
538 	    &remote_major, &remote_minor, remote_version) == 3)
539 		compat_datafellows(remote_version);
540 	else
541 		datafellows = 0;
542 	if (c->c_keytype != KT_RSA1) {
543 		if (!ssh2_capable(remote_major, remote_minor)) {
544 			debug("%s doesn't support ssh2", c->c_name);
545 			confree(s);
546 			return;
547 		}
548 	} else if (remote_major != 1) {
549 		debug("%s doesn't support ssh1", c->c_name);
550 		confree(s);
551 		return;
552 	}
553 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
554 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
555 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
556 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
557 	if (n < 0 || (size_t)n >= sizeof(buf)) {
558 		error("snprintf: buffer too small");
559 		confree(s);
560 		return;
561 	}
562 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
563 		error("write (%s): %s", c->c_name, strerror(errno));
564 		confree(s);
565 		return;
566 	}
567 	if (c->c_keytype != KT_RSA1) {
568 		keyprint(c, keygrab_ssh2(c));
569 		confree(s);
570 		return;
571 	}
572 	c->c_status = CS_SIZE;
573 	contouch(s);
574 }
575 
576 static void
577 conread(int s)
578 {
579 	con *c = &fdcon[s];
580 	size_t n;
581 
582 	if (c->c_status == CS_CON) {
583 		congreet(s);
584 		return;
585 	}
586 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
587 	if (n == 0) {
588 		error("read (%s): %s", c->c_name, strerror(errno));
589 		confree(s);
590 		return;
591 	}
592 	c->c_off += n;
593 
594 	if (c->c_off == c->c_len)
595 		switch (c->c_status) {
596 		case CS_SIZE:
597 			c->c_plen = htonl(c->c_plen);
598 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
599 			c->c_off = 0;
600 			c->c_data = xmalloc(c->c_len);
601 			c->c_status = CS_KEYS;
602 			break;
603 		case CS_KEYS:
604 			keyprint(c, keygrab_ssh1(c));
605 			confree(s);
606 			return;
607 		default:
608 			fatal("conread: invalid status %d", c->c_status);
609 			break;
610 		}
611 
612 	contouch(s);
613 }
614 
615 static void
616 conloop(void)
617 {
618 	struct timeval seltime, now;
619 	fd_set *r, *e;
620 	con *c;
621 	int i;
622 
623 	gettimeofday(&now, NULL);
624 	c = TAILQ_FIRST(&tq);
625 
626 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
627 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
628 		seltime = c->c_tv;
629 		seltime.tv_sec -= now.tv_sec;
630 		seltime.tv_usec -= now.tv_usec;
631 		if (seltime.tv_usec < 0) {
632 			seltime.tv_usec += 1000000;
633 			seltime.tv_sec--;
634 		}
635 	} else
636 		seltime.tv_sec = seltime.tv_usec = 0;
637 
638 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
639 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
640 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
641 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
642 
643 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
644 	    (errno == EAGAIN || errno == EINTR))
645 		;
646 
647 	for (i = 0; i < maxfd; i++) {
648 		if (FD_ISSET(i, e)) {
649 			error("%s: exception!", fdcon[i].c_name);
650 			confree(i);
651 		} else if (FD_ISSET(i, r))
652 			conread(i);
653 	}
654 	xfree(r);
655 	xfree(e);
656 
657 	c = TAILQ_FIRST(&tq);
658 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
659 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
660 		int s = c->c_fd;
661 
662 		c = TAILQ_NEXT(c, c_link);
663 		conrecycle(s);
664 	}
665 }
666 
667 static void
668 do_host(char *host)
669 {
670 	char *name = strnnsep(&host, " \t\n");
671 	int j;
672 
673 	if (name == NULL)
674 		return;
675 	for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
676 		if (get_keytypes & j) {
677 			while (ncon >= MAXCON)
678 				conloop();
679 			conalloc(name, *host ? host : name, j);
680 		}
681 	}
682 }
683 
684 void
685 fatal(const char *fmt,...)
686 {
687 	va_list args;
688 
689 	va_start(args, fmt);
690 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
691 	va_end(args);
692 	if (nonfatal_fatal)
693 		longjmp(kexjmp, -1);
694 	else
695 		exit(255);
696 }
697 
698 static void
699 usage(void)
700 {
701 	fprintf(stderr,
702 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
703 	    "\t\t   [host | addrlist namelist] ...\n",
704 	    __progname);
705 	exit(1);
706 }
707 
708 int
709 main(int argc, char **argv)
710 {
711 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
712 	int opt, fopt_count = 0;
713 	char *tname;
714 
715 	extern int optind;
716 	extern char *optarg;
717 
718 	TAILQ_INIT(&tq);
719 
720 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
721 	sanitise_stdfd();
722 
723 	if (argc <= 1)
724 		usage();
725 
726 	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
727 		switch (opt) {
728 		case 'H':
729 			hash_hosts = 1;
730 			break;
731 		case 'p':
732 			ssh_port = a2port(optarg);
733 			if (ssh_port <= 0) {
734 				fprintf(stderr, "Bad port '%s'\n", optarg);
735 				exit(1);
736 			}
737 			break;
738 		case 'T':
739 			timeout = convtime(optarg);
740 			if (timeout == -1 || timeout == 0) {
741 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
742 				usage();
743 			}
744 			break;
745 		case 'v':
746 			if (!debug_flag) {
747 				debug_flag = 1;
748 				log_level = SYSLOG_LEVEL_DEBUG1;
749 			}
750 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
751 				log_level++;
752 			else
753 				fatal("Too high debugging level.");
754 			break;
755 		case 'f':
756 			if (strcmp(optarg, "-") == 0)
757 				optarg = NULL;
758 			argv[fopt_count++] = optarg;
759 			break;
760 		case 't':
761 			get_keytypes = 0;
762 			tname = strtok(optarg, ",");
763 			while (tname) {
764 				int type = key_type_from_name(tname);
765 				switch (type) {
766 				case KEY_RSA1:
767 					get_keytypes |= KT_RSA1;
768 					break;
769 				case KEY_DSA:
770 					get_keytypes |= KT_DSA;
771 					break;
772 				case KEY_RSA:
773 					get_keytypes |= KT_RSA;
774 					break;
775 				case KEY_UNSPEC:
776 					fatal("unknown key type %s", tname);
777 				}
778 				tname = strtok(NULL, ",");
779 			}
780 			break;
781 		case '4':
782 			IPv4or6 = AF_INET;
783 			break;
784 		case '6':
785 			IPv4or6 = AF_INET6;
786 			break;
787 		case '?':
788 		default:
789 			usage();
790 		}
791 	}
792 	if (optind == argc && !fopt_count)
793 		usage();
794 
795 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
796 
797 	maxfd = fdlim_get(1);
798 	if (maxfd < 0)
799 		fatal("%s: fdlim_get: bad value", __progname);
800 	if (maxfd > MAXMAXFD)
801 		maxfd = MAXMAXFD;
802 	if (MAXCON <= 0)
803 		fatal("%s: not enough file descriptors", __progname);
804 	if (maxfd > fdlim_get(0))
805 		fdlim_set(maxfd);
806 	fdcon = xcalloc(maxfd, sizeof(con));
807 
808 	read_wait_nfdset = howmany(maxfd, NFDBITS);
809 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
810 
811 	if (fopt_count) {
812 		Linebuf *lb;
813 		char *line;
814 		int j;
815 
816 		for (j = 0; j < fopt_count; j++) {
817 			lb = Linebuf_alloc(argv[j], error);
818 			if (!lb)
819 				continue;
820 			while ((line = Linebuf_getline(lb)) != NULL)
821 				do_host(line);
822 			Linebuf_free(lb);
823 		}
824 	}
825 
826 	while (optind < argc)
827 		do_host(argv[optind++]);
828 
829 	while (ncon > 0)
830 		conloop();
831 
832 	return (0);
833 }
834