1/*	$NetBSD: ssh-keyscan.c,v 1.32 2023/10/25 20:19:57 christos Exp $	*/
2/* $OpenBSD: ssh-keyscan.c,v 1.153 2023/06/21 05:06:04 djm Exp $ */
3
4/*
5 * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
6 *
7 * Modification and redistribution in source and binary forms is
8 * permitted provided that due credit is given to the author and the
9 * OpenBSD project by leaving this copyright notice intact.
10 */
11
12#include "includes.h"
13__RCSID("$NetBSD: ssh-keyscan.c,v 1.32 2023/10/25 20:19:57 christos Exp $");
14
15#include <sys/param.h>
16#include <sys/types.h>
17#include <sys/socket.h>
18#include <sys/queue.h>
19#include <sys/time.h>
20#include <sys/resource.h>
21
22#ifdef WITH_OPENSSL
23#include <openssl/bn.h>
24#endif
25
26#include <errno.h>
27#include <limits.h>
28#include <netdb.h>
29#include <stdarg.h>
30#include <stdio.h>
31#include <stdlib.h>
32#include <poll.h>
33#include <signal.h>
34#include <string.h>
35#include <unistd.h>
36
37#include "xmalloc.h"
38#include "ssh.h"
39#include "sshbuf.h"
40#include "sshkey.h"
41#include "cipher.h"
42#include "digest.h"
43#include "kex.h"
44#include "compat.h"
45#include "myproposal.h"
46#include "packet.h"
47#include "dispatch.h"
48#include "log.h"
49#include "atomicio.h"
50#include "misc.h"
51#include "hostfile.h"
52#include "ssherr.h"
53#include "ssh_api.h"
54#include "dns.h"
55#include "addr.h"
56#include "fmt_scaled.h"
57
58/* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
59   Default value is AF_UNSPEC means both IPv4 and IPv6. */
60int IPv4or6 = AF_UNSPEC;
61
62int ssh_port = SSH_DEFAULT_PORT;
63
64#define KT_DSA		(1)
65#define KT_RSA		(1<<1)
66#define KT_ECDSA	(1<<2)
67#define KT_ED25519	(1<<3)
68#define KT_XMSS		(1<<4)
69#define KT_ECDSA_SK	(1<<5)
70#define KT_ED25519_SK	(1<<6)
71
72#define KT_MIN		KT_DSA
73#define KT_MAX		KT_ED25519_SK
74
75int get_cert = 0;
76int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
77
78int hash_hosts = 0;		/* Hash hostname on output */
79
80int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
81
82int found_one = 0;		/* Successfully found a key */
83
84int hashalg = -1;		/* Hash for SSHFP records or -1 for all */
85
86#define MAXMAXFD 256
87
88/* The number of seconds after which to give up on a TCP connection */
89int timeout = 5;
90
91int maxfd;
92#define MAXCON (maxfd - 10)
93
94extern char *__progname;
95struct pollfd *read_wait;
96int ncon;
97
98/*
99 * Keep a connection structure for each file descriptor.  The state
100 * associated with file descriptor n is held in fdcon[n].
101 */
102typedef struct Connection {
103	u_char c_status;	/* State of connection on this file desc. */
104#define CS_UNUSED 0		/* File descriptor unused */
105#define CS_CON 1		/* Waiting to connect/read greeting */
106#define CS_SIZE 2		/* Waiting to read initial packet size */
107#define CS_KEYS 3		/* Waiting to read public key packet */
108	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
109	int c_plen;		/* Packet length field for ssh packet */
110	int c_len;		/* Total bytes which must be read. */
111	int c_off;		/* Length of data read so far. */
112	int c_keytype;		/* Only one of KT_* */
113	sig_atomic_t c_done;	/* SSH2 done */
114	char *c_namebase;	/* Address to free for c_name and c_namelist */
115	char *c_name;		/* Hostname of connection for errors */
116	char *c_namelist;	/* Pointer to other possible addresses */
117	char *c_output_name;	/* Hostname of connection for output */
118	char *c_data;		/* Data read from this fd */
119	struct ssh *c_ssh;	/* SSH-connection */
120	struct timespec c_ts;	/* Time at which connection gets aborted */
121	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
122} con;
123
124TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
125con *fdcon;
126
127static void keyprint(con *c, struct sshkey *key);
128
129static int
130fdlim_get(int hard)
131{
132	struct rlimit rlfd;
133
134	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
135		return (-1);
136	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY ||
137	    (hard ? rlfd.rlim_max : rlfd.rlim_cur) > INT_MAX)
138		return sysconf(_SC_OPEN_MAX);
139	return hard ? rlfd.rlim_max : rlfd.rlim_cur;
140}
141
142static int
143fdlim_set(int lim)
144{
145	struct rlimit rlfd;
146
147	if (lim <= 0)
148		return (-1);
149	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
150		return (-1);
151	rlfd.rlim_cur = lim;
152	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
153		return (-1);
154	return (0);
155}
156
157/*
158 * This is an strsep function that returns a null field for adjacent
159 * separators.  This is the same as the 4.4BSD strsep, but different from the
160 * one in the GNU libc.
161 */
162static char *
163xstrsep(char **str, const char *delim)
164{
165	char *s, *e;
166
167	if (!**str)
168		return (NULL);
169
170	s = *str;
171	e = s + strcspn(s, delim);
172
173	if (*e != '\0')
174		*e++ = '\0';
175	*str = e;
176
177	return (s);
178}
179
180/*
181 * Get the next non-null token (like GNU strsep).  Strsep() will return a
182 * null token for two adjacent separators, so we may have to loop.
183 */
184static char *
185strnnsep(char **stringp, const char *delim)
186{
187	char *tok;
188
189	do {
190		tok = xstrsep(stringp, delim);
191	} while (tok && *tok == '\0');
192	return (tok);
193}
194
195
196static int
197key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
198{
199	con *c;
200
201	if ((c = ssh_get_app_data(ssh)) != NULL)
202		keyprint(c, hostkey);
203	/* always abort key exchange */
204	return -1;
205}
206
207static int
208ssh2_capable(int remote_major, int remote_minor)
209{
210	switch (remote_major) {
211	case 1:
212		if (remote_minor == 99)
213			return 1;
214		break;
215	case 2:
216		return 1;
217	default:
218		break;
219	}
220	return 0;
221}
222
223static void
224keygrab_ssh2(con *c)
225{
226	const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
227	int r;
228
229	switch (c->c_keytype) {
230	case KT_DSA:
231		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
232		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
233		break;
234	case KT_RSA:
235		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
236		    "rsa-sha2-512-cert-v01@openssh.com,"
237		    "rsa-sha2-256-cert-v01@openssh.com,"
238		    "ssh-rsa-cert-v01@openssh.com" :
239		    "rsa-sha2-512,"
240		    "rsa-sha2-256,"
241		    "ssh-rsa";
242		break;
243	case KT_ED25519:
244		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
245		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
246		break;
247	case KT_XMSS:
248		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
249		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
250		break;
251	case KT_ECDSA:
252		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
253		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
254		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
255		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
256		    "ecdsa-sha2-nistp256,"
257		    "ecdsa-sha2-nistp384,"
258		    "ecdsa-sha2-nistp521";
259		break;
260	case KT_ECDSA_SK:
261		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
262		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
263		    "sk-ecdsa-sha2-nistp256@openssh.com";
264		break;
265	case KT_ED25519_SK:
266		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
267		    "sk-ssh-ed25519-cert-v01@openssh.com" :
268		    "sk-ssh-ed25519@openssh.com";
269		break;
270	default:
271		fatal("unknown key type %d", c->c_keytype);
272		break;
273	}
274	if ((r = kex_setup(c->c_ssh, __UNCONST(myproposal))) != 0) {
275		free(c->c_ssh);
276		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
277		exit(1);
278	}
279#ifdef WITH_OPENSSL
280	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
281	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
282	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
283	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
284	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
285	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
286	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
287	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
288#endif
289	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
290	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
291	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
292	/*
293	 * do the key-exchange until an error occurs or until
294	 * the key_print_wrapper() callback sets c_done.
295	 */
296	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
297}
298
299static void
300keyprint_one(const char *host, struct sshkey *key)
301{
302	char *hostport = NULL, *hashed = NULL;
303	const char *known_host;
304	int r = 0;
305
306	found_one = 1;
307
308	if (print_sshfp) {
309		export_dns_rr(host, key, stdout, 0, hashalg);
310		return;
311	}
312
313	hostport = put_host_port(host, ssh_port);
314	lowercase(hostport);
315	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
316		fatal("host_hash failed");
317	known_host = hash_hosts ? hashed : hostport;
318	if (!get_cert)
319		r = fprintf(stdout, "%s ", known_host);
320	if (r >= 0 && sshkey_write(key, stdout) == 0)
321		(void)fputs("\n", stdout);
322	free(hashed);
323	free(hostport);
324}
325
326static void
327keyprint(con *c, struct sshkey *key)
328{
329	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
330	char *host, *ohosts;
331
332	if (key == NULL)
333		return;
334	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
335		keyprint_one(hosts, key);
336		return;
337	}
338	ohosts = hosts = xstrdup(hosts);
339	while ((host = strsep(&hosts, ",")) != NULL)
340		keyprint_one(host, key);
341	free(ohosts);
342}
343
344static int
345tcpconnect(char *host)
346{
347	struct addrinfo hints, *ai, *aitop;
348	char strport[NI_MAXSERV];
349	int gaierr, s = -1;
350
351	snprintf(strport, sizeof strport, "%d", ssh_port);
352	memset(&hints, 0, sizeof(hints));
353	hints.ai_family = IPv4or6;
354	hints.ai_socktype = SOCK_STREAM;
355	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
356		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
357		return -1;
358	}
359	for (ai = aitop; ai; ai = ai->ai_next) {
360		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
361		if (s == -1) {
362			error("socket: %s", strerror(errno));
363			continue;
364		}
365		if (set_nonblock(s) == -1)
366			fatal_f("set_nonblock(%d)", s);
367		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
368		    errno != EINPROGRESS)
369			error("connect (`%s'): %s", host, strerror(errno));
370		else
371			break;
372		close(s);
373		s = -1;
374	}
375	freeaddrinfo(aitop);
376	return s;
377}
378
379static int
380conalloc(const char *iname, const char *oname, int keytype)
381{
382	char *namebase, *name, *namelist;
383	int s;
384
385	namebase = namelist = xstrdup(iname);
386
387	do {
388		name = xstrsep(&namelist, ",");
389		if (!name) {
390			free(namebase);
391			return (-1);
392		}
393	} while ((s = tcpconnect(name)) < 0);
394
395	if (s >= maxfd)
396		fatal("conalloc: fdno %d too high", s);
397	if (fdcon[s].c_status)
398		fatal("conalloc: attempt to reuse fdno %d", s);
399
400	debug3_f("oname %s kt %d", oname, keytype);
401	fdcon[s].c_fd = s;
402	fdcon[s].c_status = CS_CON;
403	fdcon[s].c_namebase = namebase;
404	fdcon[s].c_name = name;
405	fdcon[s].c_namelist = namelist;
406	fdcon[s].c_output_name = xstrdup(oname);
407	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
408	fdcon[s].c_len = 4;
409	fdcon[s].c_off = 0;
410	fdcon[s].c_keytype = keytype;
411	monotime_ts(&fdcon[s].c_ts);
412	fdcon[s].c_ts.tv_sec += timeout;
413	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
414	read_wait[s].fd = s;
415	read_wait[s].events = POLLIN;
416	ncon++;
417	return (s);
418}
419
420static void
421confree(int s)
422{
423	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
424		fatal("confree: attempt to free bad fdno %d", s);
425	free(fdcon[s].c_namebase);
426	free(fdcon[s].c_output_name);
427	if (fdcon[s].c_status == CS_KEYS)
428		free(fdcon[s].c_data);
429	fdcon[s].c_status = CS_UNUSED;
430	fdcon[s].c_keytype = 0;
431	if (fdcon[s].c_ssh) {
432		ssh_packet_close(fdcon[s].c_ssh);
433		free(fdcon[s].c_ssh);
434		fdcon[s].c_ssh = NULL;
435	} else
436		close(s);
437	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
438	read_wait[s].fd = -1;
439	read_wait[s].events = 0;
440	ncon--;
441}
442
443static void
444contouch(int s)
445{
446	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
447	monotime_ts(&fdcon[s].c_ts);
448	fdcon[s].c_ts.tv_sec += timeout;
449	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
450}
451
452static int
453conrecycle(int s)
454{
455	con *c = &fdcon[s];
456	int ret;
457
458	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
459	confree(s);
460	return (ret);
461}
462
463static void
464congreet(int s)
465{
466	int n = 0, remote_major = 0, remote_minor = 0;
467	char buf[256], *cp;
468	char remote_version[sizeof buf];
469	size_t bufsiz;
470	con *c = &fdcon[s];
471
472	/* send client banner */
473	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
474	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
475	if (n < 0 || (size_t)n >= sizeof(buf)) {
476		error("snprintf: buffer too small");
477		confree(s);
478		return;
479	}
480	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
481		error("write (%s): %s", c->c_name, strerror(errno));
482		confree(s);
483		return;
484	}
485
486	/*
487	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
488	 * protocol identification string may be preceeded by an arbitrarily
489	 * large banner which we must read and ignore.  Loop while reading
490	 * newline-terminated lines until we have one starting with "SSH-".
491	 * The ID string cannot be longer than 255 characters although the
492	 * preceeding banner lines may (in which case they'll be discarded
493	 * in multiple iterations of the outer loop).
494	 */
495	for (;;) {
496		memset(buf, '\0', sizeof(buf));
497		bufsiz = sizeof(buf);
498		cp = buf;
499		while (bufsiz-- &&
500		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
501			if (*cp == '\r')
502				*cp = '\n';
503			cp++;
504		}
505		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
506			break;
507	}
508	if (n == 0) {
509		switch (errno) {
510		case EPIPE:
511			error("%s: Connection closed by remote host", c->c_name);
512			break;
513		case ECONNREFUSED:
514			break;
515		default:
516			error("read (%s): %s", c->c_name, strerror(errno));
517			break;
518		}
519		conrecycle(s);
520		return;
521	}
522	if (cp >= buf + sizeof(buf)) {
523		error("%s: greeting exceeds allowable length", c->c_name);
524		confree(s);
525		return;
526	}
527	if (*cp != '\n' && *cp != '\r') {
528		error("%s: bad greeting", c->c_name);
529		confree(s);
530		return;
531	}
532	*cp = '\0';
533	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
534		fatal("ssh_packet_set_connection failed");
535	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
536	ssh_set_app_data(c->c_ssh, c);	/* back link */
537	c->c_ssh->compat = 0;
538	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
539	    &remote_major, &remote_minor, remote_version) == 3)
540		compat_banner(c->c_ssh, remote_version);
541	if (!ssh2_capable(remote_major, remote_minor)) {
542		debug("%s doesn't support ssh2", c->c_name);
543		confree(s);
544		return;
545	}
546	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
547	    c->c_name, ssh_port, chop(buf));
548	keygrab_ssh2(c);
549	confree(s);
550}
551
552static void
553conread(int s)
554{
555	con *c = &fdcon[s];
556	size_t n;
557
558	if (c->c_status == CS_CON) {
559		congreet(s);
560		return;
561	}
562	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
563	if (n == 0) {
564		error("read (%s): %s", c->c_name, strerror(errno));
565		confree(s);
566		return;
567	}
568	c->c_off += n;
569
570	if (c->c_off == c->c_len)
571		switch (c->c_status) {
572		case CS_SIZE:
573			c->c_plen = htonl(c->c_plen);
574			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
575			c->c_off = 0;
576			c->c_data = xmalloc(c->c_len);
577			c->c_status = CS_KEYS;
578			break;
579		default:
580			fatal("conread: invalid status %d", c->c_status);
581			break;
582		}
583
584	contouch(s);
585}
586
587static void
588conloop(void)
589{
590	struct timespec seltime, now;
591	con *c;
592	int i;
593
594	monotime_ts(&now);
595	c = TAILQ_FIRST(&tq);
596
597	if (c && timespeccmp(&c->c_ts, &now, >))
598		timespecsub(&c->c_ts, &now, &seltime);
599	else
600		timespecclear(&seltime);
601
602	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
603		if (errno == EAGAIN || errno == EINTR)
604			continue;
605		error("poll error");
606	}
607
608	for (i = 0; i < maxfd; i++) {
609		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
610			confree(i);
611		else if (read_wait[i].revents & (POLLIN|POLLHUP))
612			conread(i);
613	}
614
615	c = TAILQ_FIRST(&tq);
616	while (c && timespeccmp(&c->c_ts, &now, <)) {
617		int s = c->c_fd;
618
619		c = TAILQ_NEXT(c, c_link);
620		conrecycle(s);
621	}
622}
623
624static void
625do_one_host(char *host)
626{
627	char *name = strnnsep(&host, " \t\n");
628	int j;
629
630	if (name == NULL)
631		return;
632	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
633		if (get_keytypes & j) {
634			while (ncon >= MAXCON)
635				conloop();
636			conalloc(name, *host ? host : name, j);
637		}
638	}
639}
640
641static void
642do_host(char *host)
643{
644	char daddr[128];
645	struct xaddr addr, end_addr;
646	u_int masklen;
647
648	if (host == NULL)
649		return;
650	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
651		/* Assume argument is a hostname */
652		do_one_host(host);
653	} else {
654		/* Argument is a CIDR range */
655		debug("CIDR range %s", host);
656		end_addr = addr;
657		if (addr_host_to_all1s(&end_addr, masklen) != 0)
658			goto badaddr;
659		/*
660		 * Note: we deliberately include the all-zero/ones addresses.
661		 */
662		for (;;) {
663			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
664 badaddr:
665				error("Invalid address %s", host);
666				return;
667			}
668			debug("CIDR expand: address %s", daddr);
669			do_one_host(daddr);
670			if (addr_cmp(&addr, &end_addr) == 0)
671				break;
672			addr_increment(&addr);
673		};
674	}
675}
676
677void
678sshfatal(const char *file, const char *func, int line, int showfunc,
679    LogLevel level, const char *suffix, const char *fmt, ...)
680{
681	va_list args;
682
683	va_start(args, fmt);
684	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
685	va_end(args);
686	cleanup_exit(255);
687}
688
689__dead static void
690usage(void)
691{
692	fprintf(stderr,
693	    "usage: ssh-keyscan [-46cDHv] [-f file] [-O option] [-p port] [-T timeout]\n"
694	    "                   [-t type] [host | addrlist namelist]\n");
695	exit(1);
696}
697
698int
699main(int argc, char **argv)
700{
701	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
702	int opt, fopt_count = 0, j;
703	char *tname, *cp, *line = NULL;
704	size_t linesize = 0;
705	FILE *fp;
706
707	extern int optind;
708	extern char *optarg;
709
710	TAILQ_INIT(&tq);
711
712	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
713	sanitise_stdfd();
714
715	if (argc <= 1)
716		usage();
717
718	while ((opt = getopt(argc, argv, "cDHv46O:p:T:t:f:")) != -1) {
719		switch (opt) {
720		case 'H':
721			hash_hosts = 1;
722			break;
723		case 'c':
724			get_cert = 1;
725			break;
726		case 'D':
727			print_sshfp = 1;
728			break;
729		case 'p':
730			ssh_port = a2port(optarg);
731			if (ssh_port <= 0) {
732				fprintf(stderr, "Bad port '%s'\n", optarg);
733				exit(1);
734			}
735			break;
736		case 'T':
737			timeout = convtime(optarg);
738			if (timeout == -1 || timeout == 0) {
739				fprintf(stderr, "Bad timeout '%s'\n", optarg);
740				usage();
741			}
742			break;
743		case 'v':
744			if (!debug_flag) {
745				debug_flag = 1;
746				log_level = SYSLOG_LEVEL_DEBUG1;
747			}
748			else if (log_level < SYSLOG_LEVEL_DEBUG3)
749				log_level++;
750			else
751				fatal("Too high debugging level.");
752			break;
753		case 'f':
754			if (strcmp(optarg, "-") == 0)
755				optarg = NULL;
756			argv[fopt_count++] = optarg;
757			break;
758		case 'O':
759			/* Maybe other misc options in the future too */
760			if (strncmp(optarg, "hashalg=", 8) != 0)
761				fatal("Unsupported -O option");
762			if ((hashalg = ssh_digest_alg_by_name(
763			    optarg + 8)) == -1)
764				fatal("Unsupported hash algorithm");
765			break;
766		case 't':
767			get_keytypes = 0;
768			tname = strtok(optarg, ",");
769			while (tname) {
770				int type = sshkey_type_from_name(tname);
771
772				switch (type) {
773				case KEY_DSA:
774					get_keytypes |= KT_DSA;
775					break;
776				case KEY_ECDSA:
777					get_keytypes |= KT_ECDSA;
778					break;
779				case KEY_RSA:
780					get_keytypes |= KT_RSA;
781					break;
782				case KEY_ED25519:
783					get_keytypes |= KT_ED25519;
784					break;
785				case KEY_XMSS:
786					get_keytypes |= KT_XMSS;
787					break;
788				case KEY_ED25519_SK:
789					get_keytypes |= KT_ED25519_SK;
790					break;
791				case KEY_ECDSA_SK:
792					get_keytypes |= KT_ECDSA_SK;
793					break;
794				case KEY_UNSPEC:
795				default:
796					fatal("Unknown key type \"%s\"", tname);
797				}
798				tname = strtok(NULL, ",");
799			}
800			break;
801		case '4':
802			IPv4or6 = AF_INET;
803			break;
804		case '6':
805			IPv4or6 = AF_INET6;
806			break;
807		default:
808			usage();
809		}
810	}
811	if (optind == argc && !fopt_count)
812		usage();
813
814	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
815
816	maxfd = fdlim_get(1);
817	if (maxfd < 0)
818		fatal("%s: fdlim_get: bad value", __progname);
819	if (maxfd > MAXMAXFD)
820		maxfd = MAXMAXFD;
821	if (MAXCON <= 0)
822		fatal("%s: not enough file descriptors", __progname);
823	if (maxfd > fdlim_get(0))
824		fdlim_set(maxfd);
825	fdcon = xcalloc(maxfd, sizeof(con));
826	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
827	for (j = 0; j < maxfd; j++)
828		read_wait[j].fd = -1;
829
830	for (j = 0; j < fopt_count; j++) {
831		if (argv[j] == NULL)
832			fp = stdin;
833		else if ((fp = fopen(argv[j], "r")) == NULL)
834			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
835
836		while (getline(&line, &linesize, fp) != -1) {
837			/* Chomp off trailing whitespace and comments */
838			if ((cp = strchr(line, '#')) == NULL)
839				cp = line + strlen(line) - 1;
840			while (cp >= line) {
841				if (*cp == ' ' || *cp == '\t' ||
842				    *cp == '\n' || *cp == '#')
843					*cp-- = '\0';
844				else
845					break;
846			}
847
848			/* Skip empty lines */
849			if (*line == '\0')
850				continue;
851
852			do_host(line);
853		}
854
855		if (ferror(fp))
856			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
857
858		fclose(fp);
859	}
860	free(line);
861
862	while (optind < argc)
863		do_host(argv[optind++]);
864
865	while (ncon > 0)
866		conloop();
867
868	return found_one ? 0 : 1;
869}
870