xref: /freebsd/crypto/openssh/ssh-keyscan.c (revision 8ef24a0d4b28fe230e20637f56869cc4148cd2ca)
1 /* $OpenBSD: ssh-keyscan.c,v 1.105 2016/02/15 09:47:49 dtucker 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. */
53 int IPv4or6 = AF_UNSPEC;
54 
55 int 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 
63 int get_cert = 0;
64 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
65 
66 int 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 */
71 int timeout = 5;
72 
73 int maxfd;
74 #define MAXCON (maxfd - 10)
75 
76 extern char *__progname;
77 fd_set *read_wait;
78 size_t read_wait_nfdset;
79 int ncon;
80 
81 struct 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  */
87 typedef 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 
109 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
110 con *fdcon;
111 
112 static void keyprint(con *c, struct sshkey *key);
113 
114 static int
115 fdlim_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 
131 static int
132 fdlim_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  */
157 static char *
158 xstrsep(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  */
179 static char *
180 strnnsep(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
191 static struct sshkey *
192 keygrab_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 
237 static int
238 key_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 
248 static int
249 ssh2_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 
264 static void
265 keygrab_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_GEX_SHA1] = kexgex_client;
306 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
307 # ifdef OPENSSL_HAS_ECC
308 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
309 # endif
310 #endif
311 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
312 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
313 	/*
314 	 * do the key-exchange until an error occurs or until
315 	 * the key_print_wrapper() callback sets c_done.
316 	 */
317 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
318 }
319 
320 static void
321 keyprint_one(char *host, struct sshkey *key)
322 {
323 	char *hostport;
324 
325 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
326 		fatal("host_hash failed");
327 
328 	hostport = put_host_port(host, ssh_port);
329 	if (!get_cert)
330 		fprintf(stdout, "%s ", hostport);
331 	sshkey_write(key, stdout);
332 	fputs("\n", stdout);
333 	free(hostport);
334 }
335 
336 static void
337 keyprint(con *c, struct sshkey *key)
338 {
339 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
340 	char *host, *ohosts;
341 
342 	if (key == NULL)
343 		return;
344 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
345 		keyprint_one(hosts, key);
346 		return;
347 	}
348 	ohosts = hosts = xstrdup(hosts);
349 	while ((host = strsep(&hosts, ",")) != NULL)
350 		keyprint_one(host, key);
351 	free(ohosts);
352 }
353 
354 static int
355 tcpconnect(char *host)
356 {
357 	struct addrinfo hints, *ai, *aitop;
358 	char strport[NI_MAXSERV];
359 	int gaierr, s = -1;
360 
361 	snprintf(strport, sizeof strport, "%d", ssh_port);
362 	memset(&hints, 0, sizeof(hints));
363 	hints.ai_family = IPv4or6;
364 	hints.ai_socktype = SOCK_STREAM;
365 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
366 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
367 		return -1;
368 	}
369 	for (ai = aitop; ai; ai = ai->ai_next) {
370 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
371 		if (s < 0) {
372 			error("socket: %s", strerror(errno));
373 			continue;
374 		}
375 		if (set_nonblock(s) == -1)
376 			fatal("%s: set_nonblock(%d)", __func__, s);
377 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
378 		    errno != EINPROGRESS)
379 			error("connect (`%s'): %s", host, strerror(errno));
380 		else
381 			break;
382 		close(s);
383 		s = -1;
384 	}
385 	freeaddrinfo(aitop);
386 	return s;
387 }
388 
389 static int
390 conalloc(char *iname, char *oname, int keytype)
391 {
392 	char *namebase, *name, *namelist;
393 	int s;
394 
395 	namebase = namelist = xstrdup(iname);
396 
397 	do {
398 		name = xstrsep(&namelist, ",");
399 		if (!name) {
400 			free(namebase);
401 			return (-1);
402 		}
403 	} while ((s = tcpconnect(name)) < 0);
404 
405 	if (s >= maxfd)
406 		fatal("conalloc: fdno %d too high", s);
407 	if (fdcon[s].c_status)
408 		fatal("conalloc: attempt to reuse fdno %d", s);
409 
410 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
411 	fdcon[s].c_fd = s;
412 	fdcon[s].c_status = CS_CON;
413 	fdcon[s].c_namebase = namebase;
414 	fdcon[s].c_name = name;
415 	fdcon[s].c_namelist = namelist;
416 	fdcon[s].c_output_name = xstrdup(oname);
417 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
418 	fdcon[s].c_len = 4;
419 	fdcon[s].c_off = 0;
420 	fdcon[s].c_keytype = keytype;
421 	gettimeofday(&fdcon[s].c_tv, NULL);
422 	fdcon[s].c_tv.tv_sec += timeout;
423 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
424 	FD_SET(s, read_wait);
425 	ncon++;
426 	return (s);
427 }
428 
429 static void
430 confree(int s)
431 {
432 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
433 		fatal("confree: attempt to free bad fdno %d", s);
434 	close(s);
435 	free(fdcon[s].c_namebase);
436 	free(fdcon[s].c_output_name);
437 	if (fdcon[s].c_status == CS_KEYS)
438 		free(fdcon[s].c_data);
439 	fdcon[s].c_status = CS_UNUSED;
440 	fdcon[s].c_keytype = 0;
441 	if (fdcon[s].c_ssh) {
442 		ssh_packet_close(fdcon[s].c_ssh);
443 		free(fdcon[s].c_ssh);
444 		fdcon[s].c_ssh = NULL;
445 	}
446 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
447 	FD_CLR(s, read_wait);
448 	ncon--;
449 }
450 
451 static void
452 contouch(int s)
453 {
454 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
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 }
459 
460 static int
461 conrecycle(int s)
462 {
463 	con *c = &fdcon[s];
464 	int ret;
465 
466 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
467 	confree(s);
468 	return (ret);
469 }
470 
471 static void
472 congreet(int s)
473 {
474 	int n = 0, remote_major = 0, remote_minor = 0;
475 	char buf[256], *cp;
476 	char remote_version[sizeof buf];
477 	size_t bufsiz;
478 	con *c = &fdcon[s];
479 
480 	for (;;) {
481 		memset(buf, '\0', sizeof(buf));
482 		bufsiz = sizeof(buf);
483 		cp = buf;
484 		while (bufsiz-- &&
485 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
486 			if (*cp == '\r')
487 				*cp = '\n';
488 			cp++;
489 		}
490 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
491 			break;
492 	}
493 	if (n == 0) {
494 		switch (errno) {
495 		case EPIPE:
496 			error("%s: Connection closed by remote host", c->c_name);
497 			break;
498 		case ECONNREFUSED:
499 			break;
500 		default:
501 			error("read (%s): %s", c->c_name, strerror(errno));
502 			break;
503 		}
504 		conrecycle(s);
505 		return;
506 	}
507 	if (*cp != '\n' && *cp != '\r') {
508 		error("%s: bad greeting", c->c_name);
509 		confree(s);
510 		return;
511 	}
512 	*cp = '\0';
513 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
514 		fatal("ssh_packet_set_connection failed");
515 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
516 	ssh_set_app_data(c->c_ssh, c);	/* back link */
517 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
518 	    &remote_major, &remote_minor, remote_version) == 3)
519 		c->c_ssh->compat = compat_datafellows(remote_version);
520 	else
521 		c->c_ssh->compat = 0;
522 	if (c->c_keytype != KT_RSA1) {
523 		if (!ssh2_capable(remote_major, remote_minor)) {
524 			debug("%s doesn't support ssh2", c->c_name);
525 			confree(s);
526 			return;
527 		}
528 	} else if (remote_major != 1) {
529 		debug("%s doesn't support ssh1", c->c_name);
530 		confree(s);
531 		return;
532 	}
533 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
534 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
535 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
536 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
537 	if (n < 0 || (size_t)n >= sizeof(buf)) {
538 		error("snprintf: buffer too small");
539 		confree(s);
540 		return;
541 	}
542 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
543 		error("write (%s): %s", c->c_name, strerror(errno));
544 		confree(s);
545 		return;
546 	}
547 	if (c->c_keytype != KT_RSA1) {
548 		keygrab_ssh2(c);
549 		confree(s);
550 		return;
551 	}
552 	c->c_status = CS_SIZE;
553 	contouch(s);
554 }
555 
556 static void
557 conread(int s)
558 {
559 	con *c = &fdcon[s];
560 	size_t n;
561 
562 	if (c->c_status == CS_CON) {
563 		congreet(s);
564 		return;
565 	}
566 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
567 	if (n == 0) {
568 		error("read (%s): %s", c->c_name, strerror(errno));
569 		confree(s);
570 		return;
571 	}
572 	c->c_off += n;
573 
574 	if (c->c_off == c->c_len)
575 		switch (c->c_status) {
576 		case CS_SIZE:
577 			c->c_plen = htonl(c->c_plen);
578 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
579 			c->c_off = 0;
580 			c->c_data = xmalloc(c->c_len);
581 			c->c_status = CS_KEYS;
582 			break;
583 #ifdef WITH_SSH1
584 		case CS_KEYS:
585 			keyprint(c, keygrab_ssh1(c));
586 			confree(s);
587 			return;
588 #endif
589 		default:
590 			fatal("conread: invalid status %d", c->c_status);
591 			break;
592 		}
593 
594 	contouch(s);
595 }
596 
597 static void
598 conloop(void)
599 {
600 	struct timeval seltime, now;
601 	fd_set *r, *e;
602 	con *c;
603 	int i;
604 
605 	gettimeofday(&now, NULL);
606 	c = TAILQ_FIRST(&tq);
607 
608 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
609 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
610 		seltime = c->c_tv;
611 		seltime.tv_sec -= now.tv_sec;
612 		seltime.tv_usec -= now.tv_usec;
613 		if (seltime.tv_usec < 0) {
614 			seltime.tv_usec += 1000000;
615 			seltime.tv_sec--;
616 		}
617 	} else
618 		timerclear(&seltime);
619 
620 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
621 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
622 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
623 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
624 
625 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
626 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
627 		;
628 
629 	for (i = 0; i < maxfd; i++) {
630 		if (FD_ISSET(i, e)) {
631 			error("%s: exception!", fdcon[i].c_name);
632 			confree(i);
633 		} else if (FD_ISSET(i, r))
634 			conread(i);
635 	}
636 	free(r);
637 	free(e);
638 
639 	c = TAILQ_FIRST(&tq);
640 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
641 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
642 		int s = c->c_fd;
643 
644 		c = TAILQ_NEXT(c, c_link);
645 		conrecycle(s);
646 	}
647 }
648 
649 static void
650 do_host(char *host)
651 {
652 	char *name = strnnsep(&host, " \t\n");
653 	int j;
654 
655 	if (name == NULL)
656 		return;
657 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
658 		if (get_keytypes & j) {
659 			while (ncon >= MAXCON)
660 				conloop();
661 			conalloc(name, *host ? host : name, j);
662 		}
663 	}
664 }
665 
666 void
667 fatal(const char *fmt,...)
668 {
669 	va_list args;
670 
671 	va_start(args, fmt);
672 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
673 	va_end(args);
674 	exit(255);
675 }
676 
677 static void
678 usage(void)
679 {
680 	fprintf(stderr,
681 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
682 	    "\t\t   [host | addrlist namelist] ...\n",
683 	    __progname);
684 	exit(1);
685 }
686 
687 int
688 main(int argc, char **argv)
689 {
690 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
691 	int opt, fopt_count = 0, j;
692 	char *tname, *cp, line[NI_MAXHOST];
693 	FILE *fp;
694 	u_long linenum;
695 
696 	extern int optind;
697 	extern char *optarg;
698 
699 	ssh_malloc_init();	/* must be called before any mallocs */
700 	__progname = ssh_get_progname(argv[0]);
701 	seed_rng();
702 	TAILQ_INIT(&tq);
703 
704 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
705 	sanitise_stdfd();
706 
707 	if (argc <= 1)
708 		usage();
709 
710 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
711 		switch (opt) {
712 		case 'H':
713 			hash_hosts = 1;
714 			break;
715 		case 'c':
716 			get_cert = 1;
717 			break;
718 		case 'p':
719 			ssh_port = a2port(optarg);
720 			if (ssh_port <= 0) {
721 				fprintf(stderr, "Bad port '%s'\n", optarg);
722 				exit(1);
723 			}
724 			break;
725 		case 'T':
726 			timeout = convtime(optarg);
727 			if (timeout == -1 || timeout == 0) {
728 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
729 				usage();
730 			}
731 			break;
732 		case 'v':
733 			if (!debug_flag) {
734 				debug_flag = 1;
735 				log_level = SYSLOG_LEVEL_DEBUG1;
736 			}
737 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
738 				log_level++;
739 			else
740 				fatal("Too high debugging level.");
741 			break;
742 		case 'f':
743 			if (strcmp(optarg, "-") == 0)
744 				optarg = NULL;
745 			argv[fopt_count++] = optarg;
746 			break;
747 		case 't':
748 			get_keytypes = 0;
749 			tname = strtok(optarg, ",");
750 			while (tname) {
751 				int type = sshkey_type_from_name(tname);
752 				switch (type) {
753 				case KEY_RSA1:
754 					get_keytypes |= KT_RSA1;
755 					break;
756 				case KEY_DSA:
757 					get_keytypes |= KT_DSA;
758 					break;
759 				case KEY_ECDSA:
760 					get_keytypes |= KT_ECDSA;
761 					break;
762 				case KEY_RSA:
763 					get_keytypes |= KT_RSA;
764 					break;
765 				case KEY_ED25519:
766 					get_keytypes |= KT_ED25519;
767 					break;
768 				case KEY_UNSPEC:
769 					fatal("unknown key type %s", tname);
770 				}
771 				tname = strtok(NULL, ",");
772 			}
773 			break;
774 		case '4':
775 			IPv4or6 = AF_INET;
776 			break;
777 		case '6':
778 			IPv4or6 = AF_INET6;
779 			break;
780 		case '?':
781 		default:
782 			usage();
783 		}
784 	}
785 	if (optind == argc && !fopt_count)
786 		usage();
787 
788 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
789 
790 	maxfd = fdlim_get(1);
791 	if (maxfd < 0)
792 		fatal("%s: fdlim_get: bad value", __progname);
793 	if (maxfd > MAXMAXFD)
794 		maxfd = MAXMAXFD;
795 	if (MAXCON <= 0)
796 		fatal("%s: not enough file descriptors", __progname);
797 	if (maxfd > fdlim_get(0))
798 		fdlim_set(maxfd);
799 	fdcon = xcalloc(maxfd, sizeof(con));
800 
801 	read_wait_nfdset = howmany(maxfd, NFDBITS);
802 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
803 
804 	for (j = 0; j < fopt_count; j++) {
805 		if (argv[j] == NULL)
806 			fp = stdin;
807 		else if ((fp = fopen(argv[j], "r")) == NULL)
808 			fatal("%s: %s: %s", __progname, argv[j],
809 			    strerror(errno));
810 		linenum = 0;
811 
812 		while (read_keyfile_line(fp,
813 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
814 		    &linenum) != -1) {
815 			/* Chomp off trailing whitespace and comments */
816 			if ((cp = strchr(line, '#')) == NULL)
817 				cp = line + strlen(line) - 1;
818 			while (cp >= line) {
819 				if (*cp == ' ' || *cp == '\t' ||
820 				    *cp == '\n' || *cp == '#')
821 					*cp-- = '\0';
822 				else
823 					break;
824 			}
825 
826 			/* Skip empty lines */
827 			if (*line == '\0')
828 				continue;
829 
830 			do_host(line);
831 		}
832 
833 		if (ferror(fp))
834 			fatal("%s: %s: %s", __progname, argv[j],
835 			    strerror(errno));
836 
837 		fclose(fp);
838 	}
839 
840 	while (optind < argc)
841 		do_host(argv[optind++]);
842 
843 	while (ncon > 0)
844 		conloop();
845 
846 	return (0);
847 }
848