xref: /netbsd-src/crypto/external/bsd/openssh/dist/ssh-keyscan.c (revision b1c86f5f087524e68db12794ee9c3e3da1ab17a0)
1 /*	$NetBSD: ssh-keyscan.c,v 1.3 2010/07/08 21:16:44 rmind Exp $	*/
2 /* $OpenBSD: ssh-keyscan.c,v 1.78 2009/01/22 10:02:34 djm Exp $ */
3 /*
4  * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
5  *
6  * Modification and redistribution in source and binary forms is
7  * permitted provided that due credit is given to the author and the
8  * OpenBSD project by leaving this copyright notice intact.
9  */
10 
11 #include "includes.h"
12 __RCSID("$NetBSD: ssh-keyscan.c,v 1.3 2010/07/08 21:16:44 rmind Exp $");
13 
14 #include <sys/param.h>
15 #include <sys/types.h>
16 #include <sys/socket.h>
17 #include <sys/queue.h>
18 #include <sys/time.h>
19 #include <sys/resource.h>
20 
21 #include <openssl/bn.h>
22 
23 #include <errno.h>
24 #include <netdb.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 
59 int get_keytypes = KT_RSA;	/* Get only RSA keys by default */
60 
61 int hash_hosts = 0;		/* Hash hostname on output */
62 
63 #define MAXMAXFD 256
64 
65 /* The number of seconds after which to give up on a TCP connection */
66 int timeout = 5;
67 
68 int maxfd;
69 #define MAXCON (maxfd - 10)
70 
71 extern char *__progname;
72 fd_set *read_wait;
73 size_t read_wait_nfdset;
74 int ncon;
75 int nonfatal_fatal = 0;
76 jmp_buf kexjmp;
77 Key *kexjmp_key;
78 
79 /*
80  * Keep a connection structure for each file descriptor.  The state
81  * associated with file descriptor n is held in fdcon[n].
82  */
83 typedef struct Connection {
84 	u_char c_status;	/* State of connection on this file desc. */
85 #define CS_UNUSED 0		/* File descriptor unused */
86 #define CS_CON 1		/* Waiting to connect/read greeting */
87 #define CS_SIZE 2		/* Waiting to read initial packet size */
88 #define CS_KEYS 3		/* Waiting to read public key packet */
89 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
90 	int c_plen;		/* Packet length field for ssh packet */
91 	int c_len;		/* Total bytes which must be read. */
92 	int c_off;		/* Length of data read so far. */
93 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
94 	char *c_namebase;	/* Address to free for c_name and c_namelist */
95 	char *c_name;		/* Hostname of connection for errors */
96 	char *c_namelist;	/* Pointer to other possible addresses */
97 	char *c_output_name;	/* Hostname of connection for output */
98 	char *c_data;		/* Data read from this fd */
99 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
100 	struct timeval c_tv;	/* Time at which connection gets aborted */
101 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
102 } con;
103 
104 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
105 con *fdcon;
106 
107 /*
108  *  This is just a wrapper around fgets() to make it usable.
109  */
110 
111 /* Stress-test.  Increase this later. */
112 #define LINEBUF_SIZE 16
113 
114 typedef struct {
115 	char *buf;
116 	u_int size;
117 	int lineno;
118 	const char *filename;
119 	FILE *stream;
120 	void (*errfun) (const char *,...);
121 } Linebuf;
122 
123 static Linebuf *
124 Linebuf_alloc(const char *filename, void (*errfun) (const char *,...))
125 {
126 	Linebuf *lb;
127 
128 	if (!(lb = malloc(sizeof(*lb)))) {
129 		if (errfun)
130 			(*errfun) ("linebuf (%s): malloc failed\n",
131 			    filename ? filename : "(stdin)");
132 		return (NULL);
133 	}
134 	if (filename) {
135 		lb->filename = filename;
136 		if (!(lb->stream = fopen(filename, "r"))) {
137 			xfree(lb);
138 			if (errfun)
139 				(*errfun) ("%s: %s\n", filename, strerror(errno));
140 			return (NULL);
141 		}
142 	} else {
143 		lb->filename = "(stdin)";
144 		lb->stream = stdin;
145 	}
146 
147 	if (!(lb->buf = malloc((lb->size = LINEBUF_SIZE)))) {
148 		if (errfun)
149 			(*errfun) ("linebuf (%s): malloc failed\n", lb->filename);
150 		xfree(lb);
151 		return (NULL);
152 	}
153 	lb->errfun = errfun;
154 	lb->lineno = 0;
155 	return (lb);
156 }
157 
158 static void
159 Linebuf_free(Linebuf * lb)
160 {
161 	fclose(lb->stream);
162 	xfree(lb->buf);
163 	xfree(lb);
164 }
165 
166 #if 0
167 static void
168 Linebuf_restart(Linebuf * lb)
169 {
170 	clearerr(lb->stream);
171 	rewind(lb->stream);
172 	lb->lineno = 0;
173 }
174 
175 static int
176 Linebuf_lineno(Linebuf * lb)
177 {
178 	return (lb->lineno);
179 }
180 #endif
181 
182 static char *
183 Linebuf_getline(Linebuf * lb)
184 {
185 	size_t n = 0;
186 	void *p;
187 
188 	lb->lineno++;
189 	for (;;) {
190 		/* Read a line */
191 		if (!fgets(&lb->buf[n], lb->size - n, lb->stream)) {
192 			if (ferror(lb->stream) && lb->errfun)
193 				(*lb->errfun)("%s: %s\n", lb->filename,
194 				    strerror(errno));
195 			return (NULL);
196 		}
197 		n = strlen(lb->buf);
198 
199 		/* Return it or an error if it fits */
200 		if (n > 0 && lb->buf[n - 1] == '\n') {
201 			lb->buf[n - 1] = '\0';
202 			return (lb->buf);
203 		}
204 		if (n != lb->size - 1) {
205 			if (lb->errfun)
206 				(*lb->errfun)("%s: skipping incomplete last line\n",
207 				    lb->filename);
208 			return (NULL);
209 		}
210 		/* Double the buffer if we need more space */
211 		lb->size *= 2;
212 		if ((p = realloc(lb->buf, lb->size)) == NULL) {
213 			lb->size /= 2;
214 			if (lb->errfun)
215 				(*lb->errfun)("linebuf (%s): realloc failed\n",
216 				    lb->filename);
217 			return (NULL);
218 		}
219 		lb->buf = p;
220 	}
221 }
222 
223 static int
224 fdlim_get(int hard)
225 {
226 	struct rlimit rlfd;
227 
228 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
229 		return (-1);
230 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
231 		return sysconf(_SC_OPEN_MAX);
232 	else
233 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
234 }
235 
236 static int
237 fdlim_set(int lim)
238 {
239 	struct rlimit rlfd;
240 
241 	if (lim <= 0)
242 		return (-1);
243 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
244 		return (-1);
245 	rlfd.rlim_cur = lim;
246 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
247 		return (-1);
248 	return (0);
249 }
250 
251 /*
252  * This is an strsep function that returns a null field for adjacent
253  * separators.  This is the same as the 4.4BSD strsep, but different from the
254  * one in the GNU libc.
255  */
256 static char *
257 xstrsep(char **str, const char *delim)
258 {
259 	char *s, *e;
260 
261 	if (!**str)
262 		return (NULL);
263 
264 	s = *str;
265 	e = s + strcspn(s, delim);
266 
267 	if (*e != '\0')
268 		*e++ = '\0';
269 	*str = e;
270 
271 	return (s);
272 }
273 
274 /*
275  * Get the next non-null token (like GNU strsep).  Strsep() will return a
276  * null token for two adjacent separators, so we may have to loop.
277  */
278 static char *
279 strnnsep(char **stringp, char *delim)
280 {
281 	char *tok;
282 
283 	do {
284 		tok = xstrsep(stringp, delim);
285 	} while (tok && *tok == '\0');
286 	return (tok);
287 }
288 
289 static Key *
290 keygrab_ssh1(con *c)
291 {
292 	static Key *rsa;
293 	static Buffer msg;
294 
295 	if (rsa == NULL) {
296 		buffer_init(&msg);
297 		rsa = key_new(KEY_RSA1);
298 	}
299 	buffer_append(&msg, c->c_data, c->c_plen);
300 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
301 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
302 		error("%s: invalid packet type", c->c_name);
303 		buffer_clear(&msg);
304 		return NULL;
305 	}
306 	buffer_consume(&msg, 8);		/* cookie */
307 
308 	/* server 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 	/* host key */
314 	(void) buffer_get_int(&msg);
315 	buffer_get_bignum(&msg, rsa->rsa->e);
316 	buffer_get_bignum(&msg, rsa->rsa->n);
317 
318 	buffer_clear(&msg);
319 
320 	return (rsa);
321 }
322 
323 static int
324 hostjump(Key *hostkey)
325 {
326 	kexjmp_key = hostkey;
327 	longjmp(kexjmp, 1);
328 }
329 
330 static int
331 ssh2_capable(int remote_major, int remote_minor)
332 {
333 	switch (remote_major) {
334 	case 1:
335 		if (remote_minor == 99)
336 			return 1;
337 		break;
338 	case 2:
339 		return 1;
340 	default:
341 		break;
342 	}
343 	return 0;
344 }
345 
346 static Key *
347 keygrab_ssh2(con *c)
348 {
349 	int j;
350 
351 	packet_set_connection(c->c_fd, c->c_fd);
352 	enable_compat20();
353 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
354 	    "ssh-dss": "ssh-rsa";
355 	c->c_kex = kex_setup(myproposal);
356 	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
357 	c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
358 	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
359 	c->c_kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
360 	c->c_kex->verify_host_key = hostjump;
361 
362 	if (!(j = setjmp(kexjmp))) {
363 		nonfatal_fatal = 1;
364 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
365 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
366 		exit(1);
367 	}
368 	nonfatal_fatal = 0;
369 	xfree(c->c_kex);
370 	c->c_kex = NULL;
371 	packet_close();
372 
373 	return j < 0? NULL : kexjmp_key;
374 }
375 
376 static void
377 keyprint(con *c, Key *key)
378 {
379 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
380 
381 	if (!key)
382 		return;
383 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
384 		fatal("host_hash failed");
385 
386 	fprintf(stdout, "%s ", host);
387 	key_write(key, stdout);
388 	fputs("\n", stdout);
389 }
390 
391 static int
392 tcpconnect(char *host)
393 {
394 	struct addrinfo hints, *ai, *aitop;
395 	char strport[NI_MAXSERV];
396 	int gaierr, s = -1;
397 
398 	snprintf(strport, sizeof strport, "%d", ssh_port);
399 	memset(&hints, 0, sizeof(hints));
400 	hints.ai_family = IPv4or6;
401 	hints.ai_socktype = SOCK_STREAM;
402 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
403 		fatal("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
404 	for (ai = aitop; ai; ai = ai->ai_next) {
405 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
406 		if (s < 0) {
407 			error("socket: %s", strerror(errno));
408 			continue;
409 		}
410 		if (set_nonblock(s) == -1)
411 			fatal("%s: set_nonblock(%d)", __func__, s);
412 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
413 		    errno != EINPROGRESS)
414 			error("connect (`%s'): %s", host, strerror(errno));
415 		else
416 			break;
417 		close(s);
418 		s = -1;
419 	}
420 	freeaddrinfo(aitop);
421 	return s;
422 }
423 
424 static int
425 conalloc(char *iname, char *oname, int keytype)
426 {
427 	char *namebase, *name, *namelist;
428 	int s;
429 
430 	namebase = namelist = xstrdup(iname);
431 
432 	do {
433 		name = xstrsep(&namelist, ",");
434 		if (!name) {
435 			xfree(namebase);
436 			return (-1);
437 		}
438 	} while ((s = tcpconnect(name)) < 0);
439 
440 	if (s >= maxfd)
441 		fatal("conalloc: fdno %d too high", s);
442 	if (fdcon[s].c_status)
443 		fatal("conalloc: attempt to reuse fdno %d", s);
444 
445 	fdcon[s].c_fd = s;
446 	fdcon[s].c_status = CS_CON;
447 	fdcon[s].c_namebase = namebase;
448 	fdcon[s].c_name = name;
449 	fdcon[s].c_namelist = namelist;
450 	fdcon[s].c_output_name = xstrdup(oname);
451 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
452 	fdcon[s].c_len = 4;
453 	fdcon[s].c_off = 0;
454 	fdcon[s].c_keytype = keytype;
455 	gettimeofday(&fdcon[s].c_tv, NULL);
456 	fdcon[s].c_tv.tv_sec += timeout;
457 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
458 	FD_SET(s, read_wait);
459 	ncon++;
460 	return (s);
461 }
462 
463 static void
464 confree(int s)
465 {
466 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
467 		fatal("confree: attempt to free bad fdno %d", s);
468 	close(s);
469 	xfree(fdcon[s].c_namebase);
470 	xfree(fdcon[s].c_output_name);
471 	if (fdcon[s].c_status == CS_KEYS)
472 		xfree(fdcon[s].c_data);
473 	fdcon[s].c_status = CS_UNUSED;
474 	fdcon[s].c_keytype = 0;
475 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
476 	FD_CLR(s, read_wait);
477 	ncon--;
478 }
479 
480 static void
481 contouch(int s)
482 {
483 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
484 	gettimeofday(&fdcon[s].c_tv, NULL);
485 	fdcon[s].c_tv.tv_sec += timeout;
486 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
487 }
488 
489 static int
490 conrecycle(int s)
491 {
492 	con *c = &fdcon[s];
493 	int ret;
494 
495 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
496 	confree(s);
497 	return (ret);
498 }
499 
500 static void
501 congreet(int s)
502 {
503 	int n = 0, remote_major = 0, remote_minor = 0;
504 	char buf[256], *cp;
505 	char remote_version[sizeof buf];
506 	size_t bufsiz;
507 	con *c = &fdcon[s];
508 
509 	for (;;) {
510 		memset(buf, '\0', sizeof(buf));
511 		bufsiz = sizeof(buf);
512 		cp = buf;
513 		while (bufsiz-- &&
514 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
515 			if (*cp == '\r')
516 				*cp = '\n';
517 			cp++;
518 		}
519 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
520 			break;
521 	}
522 	if (n == 0) {
523 		switch (errno) {
524 		case EPIPE:
525 			error("%s: Connection closed by remote host", c->c_name);
526 			break;
527 		case ECONNREFUSED:
528 			break;
529 		default:
530 			error("read (%s): %s", c->c_name, strerror(errno));
531 			break;
532 		}
533 		conrecycle(s);
534 		return;
535 	}
536 	if (*cp != '\n' && *cp != '\r') {
537 		error("%s: bad greeting", c->c_name);
538 		confree(s);
539 		return;
540 	}
541 	*cp = '\0';
542 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
543 	    &remote_major, &remote_minor, remote_version) == 3)
544 		compat_datafellows(remote_version);
545 	else
546 		datafellows = 0;
547 	if (c->c_keytype != KT_RSA1) {
548 		if (!ssh2_capable(remote_major, remote_minor)) {
549 			debug("%s doesn't support ssh2", c->c_name);
550 			confree(s);
551 			return;
552 		}
553 	} else if (remote_major != 1) {
554 		debug("%s doesn't support ssh1", c->c_name);
555 		confree(s);
556 		return;
557 	}
558 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
559 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
560 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
561 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
562 	if (n < 0 || (size_t)n >= sizeof(buf)) {
563 		error("snprintf: buffer too small");
564 		confree(s);
565 		return;
566 	}
567 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
568 		error("write (%s): %s", c->c_name, strerror(errno));
569 		confree(s);
570 		return;
571 	}
572 	if (c->c_keytype != KT_RSA1) {
573 		keyprint(c, keygrab_ssh2(c));
574 		confree(s);
575 		return;
576 	}
577 	c->c_status = CS_SIZE;
578 	contouch(s);
579 }
580 
581 static void
582 conread(int s)
583 {
584 	con *c = &fdcon[s];
585 	size_t n;
586 
587 	if (c->c_status == CS_CON) {
588 		congreet(s);
589 		return;
590 	}
591 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
592 	if (n == 0) {
593 		error("read (%s): %s", c->c_name, strerror(errno));
594 		confree(s);
595 		return;
596 	}
597 	c->c_off += n;
598 
599 	if (c->c_off == c->c_len)
600 		switch (c->c_status) {
601 		case CS_SIZE:
602 			c->c_plen = htonl(c->c_plen);
603 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
604 			c->c_off = 0;
605 			c->c_data = xmalloc(c->c_len);
606 			c->c_status = CS_KEYS;
607 			break;
608 		case CS_KEYS:
609 			keyprint(c, keygrab_ssh1(c));
610 			confree(s);
611 			return;
612 		default:
613 			fatal("conread: invalid status %d", c->c_status);
614 			break;
615 		}
616 
617 	contouch(s);
618 }
619 
620 static void
621 conloop(void)
622 {
623 	struct timeval seltime, now;
624 	fd_set *r, *e;
625 	con *c;
626 	int i;
627 
628 	gettimeofday(&now, NULL);
629 	c = TAILQ_FIRST(&tq);
630 
631 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
632 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
633 		seltime = c->c_tv;
634 		seltime.tv_sec -= now.tv_sec;
635 		seltime.tv_usec -= now.tv_usec;
636 		if (seltime.tv_usec < 0) {
637 			seltime.tv_usec += 1000000;
638 			seltime.tv_sec--;
639 		}
640 	} else
641 		seltime.tv_sec = seltime.tv_usec = 0;
642 
643 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
644 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
645 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
646 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
647 
648 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
649 	    (errno == EAGAIN || errno == EINTR))
650 		;
651 
652 	for (i = 0; i < maxfd; i++) {
653 		if (FD_ISSET(i, e)) {
654 			error("%s: exception!", fdcon[i].c_name);
655 			confree(i);
656 		} else if (FD_ISSET(i, r))
657 			conread(i);
658 	}
659 	xfree(r);
660 	xfree(e);
661 
662 	c = TAILQ_FIRST(&tq);
663 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
664 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
665 		int s = c->c_fd;
666 
667 		c = TAILQ_NEXT(c, c_link);
668 		conrecycle(s);
669 	}
670 }
671 
672 static void
673 do_host(char *host)
674 {
675 	char *name = strnnsep(&host, " \t\n");
676 	int j;
677 
678 	if (name == NULL)
679 		return;
680 	for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
681 		if (get_keytypes & j) {
682 			while (ncon >= MAXCON)
683 				conloop();
684 			conalloc(name, *host ? host : name, j);
685 		}
686 	}
687 }
688 
689 void
690 fatal(const char *fmt,...)
691 {
692 	va_list args;
693 
694 	va_start(args, fmt);
695 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
696 	va_end(args);
697 	if (nonfatal_fatal)
698 		longjmp(kexjmp, -1);
699 	else
700 		exit(255);
701 }
702 
703 static void
704 usage(void)
705 {
706 	fprintf(stderr,
707 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
708 	    "\t\t   [host | addrlist namelist] ...\n",
709 	    __progname);
710 	exit(1);
711 }
712 
713 int
714 main(int argc, char **argv)
715 {
716 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
717 	int opt, fopt_count = 0;
718 	char *tname;
719 
720 	extern int optind;
721 	extern char *optarg;
722 
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, "Hv46p:T:t:f:")) != -1) {
732 		switch (opt) {
733 		case 'H':
734 			hash_hosts = 1;
735 			break;
736 		case 'p':
737 			ssh_port = a2port(optarg);
738 			if (ssh_port <= 0) {
739 				fprintf(stderr, "Bad port '%s'\n", optarg);
740 				exit(1);
741 			}
742 			break;
743 		case 'T':
744 			timeout = convtime(optarg);
745 			if (timeout == -1 || timeout == 0) {
746 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
747 				usage();
748 			}
749 			break;
750 		case 'v':
751 			if (!debug_flag) {
752 				debug_flag = 1;
753 				log_level = SYSLOG_LEVEL_DEBUG1;
754 			}
755 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
756 				log_level++;
757 			else
758 				fatal("Too high debugging level.");
759 			break;
760 		case 'f':
761 			if (strcmp(optarg, "-") == 0)
762 				optarg = NULL;
763 			argv[fopt_count++] = optarg;
764 			break;
765 		case 't':
766 			get_keytypes = 0;
767 			tname = strtok(optarg, ",");
768 			while (tname) {
769 				int type = key_type_from_name(tname);
770 				switch (type) {
771 				case KEY_RSA1:
772 					get_keytypes |= KT_RSA1;
773 					break;
774 				case KEY_DSA:
775 					get_keytypes |= KT_DSA;
776 					break;
777 				case KEY_RSA:
778 					get_keytypes |= KT_RSA;
779 					break;
780 				case KEY_UNSPEC:
781 					fatal("unknown key type %s", tname);
782 				}
783 				tname = strtok(NULL, ",");
784 			}
785 			break;
786 		case '4':
787 			IPv4or6 = AF_INET;
788 			break;
789 		case '6':
790 			IPv4or6 = AF_INET6;
791 			break;
792 		case '?':
793 		default:
794 			usage();
795 		}
796 	}
797 	if (optind == argc && !fopt_count)
798 		usage();
799 
800 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
801 
802 	maxfd = fdlim_get(1);
803 	if (maxfd < 0)
804 		fatal("%s: fdlim_get: bad value", __progname);
805 	if (maxfd > MAXMAXFD)
806 		maxfd = MAXMAXFD;
807 	if (MAXCON <= 0)
808 		fatal("%s: not enough file descriptors", __progname);
809 	if (maxfd > fdlim_get(0))
810 		fdlim_set(maxfd);
811 	fdcon = xcalloc(maxfd, sizeof(con));
812 
813 	read_wait_nfdset = howmany(maxfd, NFDBITS);
814 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
815 
816 	if (fopt_count) {
817 		Linebuf *lb;
818 		char *line;
819 		int j;
820 
821 		for (j = 0; j < fopt_count; j++) {
822 			lb = Linebuf_alloc(argv[j], error);
823 			if (!lb)
824 				continue;
825 			while ((line = Linebuf_getline(lb)) != NULL)
826 				do_host(line);
827 			Linebuf_free(lb);
828 		}
829 	}
830 
831 	while (optind < argc)
832 		do_host(argv[optind++]);
833 
834 	while (ncon > 0)
835 		conloop();
836 
837 	return (0);
838 }
839