ssh-keyscan.c revision 323129 
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. */
53int IPv4or6 = AF_UNSPEC;
54
55int 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
63int get_cert = 0;
64int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
65
66int 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 */
71int timeout = 5;
72
73int maxfd;
74#define MAXCON (maxfd - 10)
75
76extern char *__progname;
77fd_set *read_wait;
78size_t read_wait_nfdset;
79int ncon;
80
81struct 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 */
87typedef 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
109TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
110con *fdcon;
111
112static void keyprint(con *c, struct sshkey *key);
113
114static int
115fdlim_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
131static int
132fdlim_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 */
157static char *
158xstrsep(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 */
179static char *
180strnnsep(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
191static struct sshkey *
192keygrab_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
237static int
238key_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
248static int
249ssh2_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
264static void
265keygrab_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
323static void
324keyprint_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
339static void
340keyprint(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
357static int
358tcpconnect(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
392static int
393conalloc(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
432static void
433confree(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
454static void
455contouch(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
463static int
464conrecycle(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
474static void
475congreet(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
559static void
560conread(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
600static void
601conloop(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
652static void
653do_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
669void
670fatal(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
680static void
681usage(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
690int
691main(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