xref: /openbsd-src/usr.bin/ssh/ssh-keyscan.c (revision ff0e7be1ebbcc809ea8ad2b6dafe215824da9e46) 
1 /* $OpenBSD: ssh-keyscan.c,v 1.152 2023/03/31 04:21:56 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 #ifdef WITH_OPENSSL
17 #include <openssl/bn.h>
18 #endif
19 
20 #include <errno.h>
21 #include <netdb.h>
22 #include <stdarg.h>
23 #include <stdio.h>
24 #include <stdlib.h>
25 #include <poll.h>
26 #include <signal.h>
27 #include <string.h>
28 #include <unistd.h>
29 
30 #include "xmalloc.h"
31 #include "ssh.h"
32 #include "sshbuf.h"
33 #include "sshkey.h"
34 #include "cipher.h"
35 #include "digest.h"
36 #include "kex.h"
37 #include "compat.h"
38 #include "myproposal.h"
39 #include "packet.h"
40 #include "dispatch.h"
41 #include "log.h"
42 #include "atomicio.h"
43 #include "misc.h"
44 #include "hostfile.h"
45 #include "ssherr.h"
46 #include "ssh_api.h"
47 #include "dns.h"
48 #include "addr.h"
49 
50 /* Flag indicating whether IPv4 or IPv6.  This can be set on the command line.
51    Default value is AF_UNSPEC means both IPv4 and IPv6. */
52 int IPv4or6 = AF_UNSPEC;
53 
54 int ssh_port = SSH_DEFAULT_PORT;
55 
56 #define KT_DSA		(1)
57 #define KT_RSA		(1<<1)
58 #define KT_ECDSA	(1<<2)
59 #define KT_ED25519	(1<<3)
60 #define KT_XMSS		(1<<4)
61 #define KT_ECDSA_SK	(1<<5)
62 #define KT_ED25519_SK	(1<<6)
63 
64 #define KT_MIN		KT_DSA
65 #define KT_MAX		KT_ED25519_SK
66 
67 int get_cert = 0;
68 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519|KT_ECDSA_SK|KT_ED25519_SK;
69 
70 int hash_hosts = 0;		/* Hash hostname on output */
71 
72 int print_sshfp = 0;		/* Print SSHFP records instead of known_hosts */
73 
74 int found_one = 0;		/* Successfully found a key */
75 
76 int hashalg = -1;		/* Hash for SSHFP records or -1 for all */
77 
78 #define MAXMAXFD 256
79 
80 /* The number of seconds after which to give up on a TCP connection */
81 int timeout = 5;
82 
83 int maxfd;
84 #define MAXCON (maxfd - 10)
85 
86 extern char *__progname;
87 struct pollfd *read_wait;
88 int ncon;
89 
90 /*
91  * Keep a connection structure for each file descriptor.  The state
92  * associated with file descriptor n is held in fdcon[n].
93  */
94 typedef struct Connection {
95 	u_char c_status;	/* State of connection on this file desc. */
96 #define CS_UNUSED 0		/* File descriptor unused */
97 #define CS_CON 1		/* Waiting to connect/read greeting */
98 #define CS_SIZE 2		/* Waiting to read initial packet size */
99 #define CS_KEYS 3		/* Waiting to read public key packet */
100 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
101 	int c_plen;		/* Packet length field for ssh packet */
102 	int c_len;		/* Total bytes which must be read. */
103 	int c_off;		/* Length of data read so far. */
104 	int c_keytype;		/* Only one of KT_* */
105 	sig_atomic_t c_done;	/* SSH2 done */
106 	char *c_namebase;	/* Address to free for c_name and c_namelist */
107 	char *c_name;		/* Hostname of connection for errors */
108 	char *c_namelist;	/* Pointer to other possible addresses */
109 	char *c_output_name;	/* Hostname of connection for output */
110 	char *c_data;		/* Data read from this fd */
111 	struct ssh *c_ssh;	/* SSH-connection */
112 	struct timespec c_ts;	/* Time at which connection gets aborted */
113 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
114 } con;
115 
116 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
117 con *fdcon;
118 
119 static void keyprint(con *c, struct sshkey *key);
120 
121 static int
122 fdlim_get(int hard)
123 {
124 	struct rlimit rlfd;
125 
126 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
127 		return (-1);
128 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
129 		return sysconf(_SC_OPEN_MAX);
130 	else
131 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
132 }
133 
134 static int
135 fdlim_set(int lim)
136 {
137 	struct rlimit rlfd;
138 
139 	if (lim <= 0)
140 		return (-1);
141 	if (getrlimit(RLIMIT_NOFILE, &rlfd) == -1)
142 		return (-1);
143 	rlfd.rlim_cur = lim;
144 	if (setrlimit(RLIMIT_NOFILE, &rlfd) == -1)
145 		return (-1);
146 	return (0);
147 }
148 
149 /*
150  * This is an strsep function that returns a null field for adjacent
151  * separators.  This is the same as the 4.4BSD strsep, but different from the
152  * one in the GNU libc.
153  */
154 static char *
155 xstrsep(char **str, const char *delim)
156 {
157 	char *s, *e;
158 
159 	if (!**str)
160 		return (NULL);
161 
162 	s = *str;
163 	e = s + strcspn(s, delim);
164 
165 	if (*e != '\0')
166 		*e++ = '\0';
167 	*str = e;
168 
169 	return (s);
170 }
171 
172 /*
173  * Get the next non-null token (like GNU strsep).  Strsep() will return a
174  * null token for two adjacent separators, so we may have to loop.
175  */
176 static char *
177 strnnsep(char **stringp, char *delim)
178 {
179 	char *tok;
180 
181 	do {
182 		tok = xstrsep(stringp, delim);
183 	} while (tok && *tok == '\0');
184 	return (tok);
185 }
186 
187 
188 static int
189 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
190 {
191 	con *c;
192 
193 	if ((c = ssh_get_app_data(ssh)) != NULL)
194 		keyprint(c, hostkey);
195 	/* always abort key exchange */
196 	return -1;
197 }
198 
199 static int
200 ssh2_capable(int remote_major, int remote_minor)
201 {
202 	switch (remote_major) {
203 	case 1:
204 		if (remote_minor == 99)
205 			return 1;
206 		break;
207 	case 2:
208 		return 1;
209 	default:
210 		break;
211 	}
212 	return 0;
213 }
214 
215 static void
216 keygrab_ssh2(con *c)
217 {
218 	char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
219 	int r;
220 
221 	switch (c->c_keytype) {
222 	case KT_DSA:
223 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
224 		    "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
225 		break;
226 	case KT_RSA:
227 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
228 		    "rsa-sha2-512-cert-v01@openssh.com,"
229 		    "rsa-sha2-256-cert-v01@openssh.com,"
230 		    "ssh-rsa-cert-v01@openssh.com" :
231 		    "rsa-sha2-512,"
232 		    "rsa-sha2-256,"
233 		    "ssh-rsa";
234 		break;
235 	case KT_ED25519:
236 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
237 		    "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
238 		break;
239 	case KT_XMSS:
240 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
241 		    "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
242 		break;
243 	case KT_ECDSA:
244 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
245 		    "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
246 		    "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
247 		    "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
248 		    "ecdsa-sha2-nistp256,"
249 		    "ecdsa-sha2-nistp384,"
250 		    "ecdsa-sha2-nistp521";
251 		break;
252 	case KT_ECDSA_SK:
253 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
254 		    "sk-ecdsa-sha2-nistp256-cert-v01@openssh.com" :
255 		    "sk-ecdsa-sha2-nistp256@openssh.com";
256 		break;
257 	case KT_ED25519_SK:
258 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
259 		    "sk-ssh-ed25519-cert-v01@openssh.com" :
260 		    "sk-ssh-ed25519@openssh.com";
261 		break;
262 	default:
263 		fatal("unknown key type %d", c->c_keytype);
264 		break;
265 	}
266 	if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
267 		free(c->c_ssh);
268 		fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
269 		exit(1);
270 	}
271 #ifdef WITH_OPENSSL
272 	c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
273 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
274 	c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
275 	c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
276 	c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
277 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
278 	c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
279 	c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
280 #endif
281 	c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
282 	c->c_ssh->kex->kex[KEX_KEM_SNTRUP761X25519_SHA512] = kex_gen_client;
283 	ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
284 	/*
285 	 * do the key-exchange until an error occurs or until
286 	 * the key_print_wrapper() callback sets c_done.
287 	 */
288 	ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
289 }
290 
291 static void
292 keyprint_one(const char *host, struct sshkey *key)
293 {
294 	char *hostport = NULL, *hashed = NULL;
295 	const char *known_host;
296 	int r = 0;
297 
298 	found_one = 1;
299 
300 	if (print_sshfp) {
301 		export_dns_rr(host, key, stdout, 0, hashalg);
302 		return;
303 	}
304 
305 	hostport = put_host_port(host, ssh_port);
306 	lowercase(hostport);
307 	if (hash_hosts && (hashed = host_hash(hostport, NULL, 0)) == NULL)
308 		fatal("host_hash failed");
309 	known_host = hash_hosts ? hashed : hostport;
310 	if (!get_cert)
311 		r = fprintf(stdout, "%s ", known_host);
312 	if (r >= 0 && sshkey_write(key, stdout) == 0)
313 		(void)fputs("\n", stdout);
314 	free(hashed);
315 	free(hostport);
316 }
317 
318 static void
319 keyprint(con *c, struct sshkey *key)
320 {
321 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
322 	char *host, *ohosts;
323 
324 	if (key == NULL)
325 		return;
326 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
327 		keyprint_one(hosts, key);
328 		return;
329 	}
330 	ohosts = hosts = xstrdup(hosts);
331 	while ((host = strsep(&hosts, ",")) != NULL)
332 		keyprint_one(host, key);
333 	free(ohosts);
334 }
335 
336 static int
337 tcpconnect(char *host)
338 {
339 	struct addrinfo hints, *ai, *aitop;
340 	char strport[NI_MAXSERV];
341 	int gaierr, s = -1;
342 
343 	snprintf(strport, sizeof strport, "%d", ssh_port);
344 	memset(&hints, 0, sizeof(hints));
345 	hints.ai_family = IPv4or6;
346 	hints.ai_socktype = SOCK_STREAM;
347 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
348 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
349 		return -1;
350 	}
351 	for (ai = aitop; ai; ai = ai->ai_next) {
352 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
353 		if (s == -1) {
354 			error("socket: %s", strerror(errno));
355 			continue;
356 		}
357 		if (set_nonblock(s) == -1)
358 			fatal_f("set_nonblock(%d)", s);
359 		if (connect(s, ai->ai_addr, ai->ai_addrlen) == -1 &&
360 		    errno != EINPROGRESS)
361 			error("connect (`%s'): %s", host, strerror(errno));
362 		else
363 			break;
364 		close(s);
365 		s = -1;
366 	}
367 	freeaddrinfo(aitop);
368 	return s;
369 }
370 
371 static int
372 conalloc(const char *iname, const char *oname, int keytype)
373 {
374 	char *namebase, *name, *namelist;
375 	int s;
376 
377 	namebase = namelist = xstrdup(iname);
378 
379 	do {
380 		name = xstrsep(&namelist, ",");
381 		if (!name) {
382 			free(namebase);
383 			return (-1);
384 		}
385 	} while ((s = tcpconnect(name)) < 0);
386 
387 	if (s >= maxfd)
388 		fatal("conalloc: fdno %d too high", s);
389 	if (fdcon[s].c_status)
390 		fatal("conalloc: attempt to reuse fdno %d", s);
391 
392 	debug3_f("oname %s kt %d", oname, keytype);
393 	fdcon[s].c_fd = s;
394 	fdcon[s].c_status = CS_CON;
395 	fdcon[s].c_namebase = namebase;
396 	fdcon[s].c_name = name;
397 	fdcon[s].c_namelist = namelist;
398 	fdcon[s].c_output_name = xstrdup(oname);
399 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
400 	fdcon[s].c_len = 4;
401 	fdcon[s].c_off = 0;
402 	fdcon[s].c_keytype = keytype;
403 	monotime_ts(&fdcon[s].c_ts);
404 	fdcon[s].c_ts.tv_sec += timeout;
405 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
406 	read_wait[s].fd = s;
407 	read_wait[s].events = POLLIN;
408 	ncon++;
409 	return (s);
410 }
411 
412 static void
413 confree(int s)
414 {
415 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
416 		fatal("confree: attempt to free bad fdno %d", s);
417 	free(fdcon[s].c_namebase);
418 	free(fdcon[s].c_output_name);
419 	if (fdcon[s].c_status == CS_KEYS)
420 		free(fdcon[s].c_data);
421 	fdcon[s].c_status = CS_UNUSED;
422 	fdcon[s].c_keytype = 0;
423 	if (fdcon[s].c_ssh) {
424 		ssh_packet_close(fdcon[s].c_ssh);
425 		free(fdcon[s].c_ssh);
426 		fdcon[s].c_ssh = NULL;
427 	} else
428 		close(s);
429 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
430 	read_wait[s].fd = -1;
431 	read_wait[s].events = 0;
432 	ncon--;
433 }
434 
435 static void
436 contouch(int s)
437 {
438 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
439 	monotime_ts(&fdcon[s].c_ts);
440 	fdcon[s].c_ts.tv_sec += timeout;
441 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
442 }
443 
444 static int
445 conrecycle(int s)
446 {
447 	con *c = &fdcon[s];
448 	int ret;
449 
450 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
451 	confree(s);
452 	return (ret);
453 }
454 
455 static void
456 congreet(int s)
457 {
458 	int n = 0, remote_major = 0, remote_minor = 0;
459 	char buf[256], *cp;
460 	char remote_version[sizeof buf];
461 	size_t bufsiz;
462 	con *c = &fdcon[s];
463 
464 	/* send client banner */
465 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
466 	    PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
467 	if (n < 0 || (size_t)n >= sizeof(buf)) {
468 		error("snprintf: buffer too small");
469 		confree(s);
470 		return;
471 	}
472 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
473 		error("write (%s): %s", c->c_name, strerror(errno));
474 		confree(s);
475 		return;
476 	}
477 
478 	/*
479 	 * Read the server banner as per RFC4253 section 4.2.  The "SSH-"
480 	 * protocol identification string may be preceeded by an arbitrarily
481 	 * large banner which we must read and ignore.  Loop while reading
482 	 * newline-terminated lines until we have one starting with "SSH-".
483 	 * The ID string cannot be longer than 255 characters although the
484 	 * preceeding banner lines may (in which case they'll be discarded
485 	 * in multiple iterations of the outer loop).
486 	 */
487 	for (;;) {
488 		memset(buf, '\0', sizeof(buf));
489 		bufsiz = sizeof(buf);
490 		cp = buf;
491 		while (bufsiz-- &&
492 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
493 			if (*cp == '\r')
494 				*cp = '\n';
495 			cp++;
496 		}
497 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
498 			break;
499 	}
500 	if (n == 0) {
501 		switch (errno) {
502 		case EPIPE:
503 			error("%s: Connection closed by remote host", c->c_name);
504 			break;
505 		case ECONNREFUSED:
506 			break;
507 		default:
508 			error("read (%s): %s", c->c_name, strerror(errno));
509 			break;
510 		}
511 		conrecycle(s);
512 		return;
513 	}
514 	if (cp >= buf + sizeof(buf)) {
515 		error("%s: greeting exceeds allowable length", c->c_name);
516 		confree(s);
517 		return;
518 	}
519 	if (*cp != '\n' && *cp != '\r') {
520 		error("%s: bad greeting", c->c_name);
521 		confree(s);
522 		return;
523 	}
524 	*cp = '\0';
525 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
526 		fatal("ssh_packet_set_connection failed");
527 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
528 	ssh_set_app_data(c->c_ssh, c);	/* back link */
529 	c->c_ssh->compat = 0;
530 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
531 	    &remote_major, &remote_minor, remote_version) == 3)
532 		compat_banner(c->c_ssh, remote_version);
533 	if (!ssh2_capable(remote_major, remote_minor)) {
534 		debug("%s doesn't support ssh2", c->c_name);
535 		confree(s);
536 		return;
537 	}
538 	fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
539 	    c->c_name, ssh_port, chop(buf));
540 	keygrab_ssh2(c);
541 	confree(s);
542 }
543 
544 static void
545 conread(int s)
546 {
547 	con *c = &fdcon[s];
548 	size_t n;
549 
550 	if (c->c_status == CS_CON) {
551 		congreet(s);
552 		return;
553 	}
554 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
555 	if (n == 0) {
556 		error("read (%s): %s", c->c_name, strerror(errno));
557 		confree(s);
558 		return;
559 	}
560 	c->c_off += n;
561 
562 	if (c->c_off == c->c_len)
563 		switch (c->c_status) {
564 		case CS_SIZE:
565 			c->c_plen = htonl(c->c_plen);
566 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
567 			c->c_off = 0;
568 			c->c_data = xmalloc(c->c_len);
569 			c->c_status = CS_KEYS;
570 			break;
571 		default:
572 			fatal("conread: invalid status %d", c->c_status);
573 			break;
574 		}
575 
576 	contouch(s);
577 }
578 
579 static void
580 conloop(void)
581 {
582 	struct timespec seltime, now;
583 	con *c;
584 	int i;
585 
586 	monotime_ts(&now);
587 	c = TAILQ_FIRST(&tq);
588 
589 	if (c && timespeccmp(&c->c_ts, &now, >))
590 		timespecsub(&c->c_ts, &now, &seltime);
591 	else
592 		timespecclear(&seltime);
593 
594 	while (ppoll(read_wait, maxfd, &seltime, NULL) == -1) {
595 		if (errno == EAGAIN || errno == EINTR)
596 			continue;
597 		error("poll error");
598 	}
599 
600 	for (i = 0; i < maxfd; i++) {
601 		if (read_wait[i].revents & (POLLHUP|POLLERR|POLLNVAL))
602 			confree(i);
603 		else if (read_wait[i].revents & (POLLIN|POLLHUP))
604 			conread(i);
605 	}
606 
607 	c = TAILQ_FIRST(&tq);
608 	while (c && timespeccmp(&c->c_ts, &now, <)) {
609 		int s = c->c_fd;
610 
611 		c = TAILQ_NEXT(c, c_link);
612 		conrecycle(s);
613 	}
614 }
615 
616 static void
617 do_one_host(char *host)
618 {
619 	char *name = strnnsep(&host, " \t\n");
620 	int j;
621 
622 	if (name == NULL)
623 		return;
624 	for (j = KT_MIN; j <= KT_MAX; j *= 2) {
625 		if (get_keytypes & j) {
626 			while (ncon >= MAXCON)
627 				conloop();
628 			conalloc(name, *host ? host : name, j);
629 		}
630 	}
631 }
632 
633 static void
634 do_host(char *host)
635 {
636 	char daddr[128];
637 	struct xaddr addr, end_addr;
638 	u_int masklen;
639 
640 	if (host == NULL)
641 		return;
642 	if (addr_pton_cidr(host, &addr, &masklen) != 0) {
643 		/* Assume argument is a hostname */
644 		do_one_host(host);
645 	} else {
646 		/* Argument is a CIDR range */
647 		debug("CIDR range %s", host);
648 		end_addr = addr;
649 		if (addr_host_to_all1s(&end_addr, masklen) != 0)
650 			goto badaddr;
651 		/*
652 		 * Note: we deliberately include the all-zero/ones addresses.
653 		 */
654 		for (;;) {
655 			if (addr_ntop(&addr, daddr, sizeof(daddr)) != 0) {
656  badaddr:
657 				error("Invalid address %s", host);
658 				return;
659 			}
660 			debug("CIDR expand: address %s", daddr);
661 			do_one_host(daddr);
662 			if (addr_cmp(&addr, &end_addr) == 0)
663 				break;
664 			addr_increment(&addr);
665 		};
666 	}
667 }
668 
669 void
670 sshfatal(const char *file, const char *func, int line, int showfunc,
671     LogLevel level, const char *suffix, const char *fmt, ...)
672 {
673 	va_list args;
674 
675 	va_start(args, fmt);
676 	sshlogv(file, func, line, showfunc, level, suffix, fmt, args);
677 	va_end(args);
678 	cleanup_exit(255);
679 }
680 
681 static void
682 usage(void)
683 {
684 	fprintf(stderr,
685 	    "usage: ssh-keyscan [-46cDHv] [-f file] [-O option] [-p port] [-T timeout]\n"
686 	    "                   [-t type] [host | addrlist namelist]\n");
687 	exit(1);
688 }
689 
690 int
691 main(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 = NULL;
696 	size_t linesize = 0;
697 	FILE *fp;
698 
699 	extern int optind;
700 	extern char *optarg;
701 
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, "cDHv46O:p: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 'D':
719 			print_sshfp = 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 'O':
751 			/* Maybe other misc options in the future too */
752 			if (strncmp(optarg, "hashalg=", 8) != 0)
753 				fatal("Unsupported -O option");
754 			if ((hashalg = ssh_digest_alg_by_name(
755 			    optarg + 8)) == -1)
756 				fatal("Unsupported hash algorithm");
757 			break;
758 		case 't':
759 			get_keytypes = 0;
760 			tname = strtok(optarg, ",");
761 			while (tname) {
762 				int type = sshkey_type_from_name(tname);
763 
764 				switch (type) {
765 				case KEY_DSA:
766 					get_keytypes |= KT_DSA;
767 					break;
768 				case KEY_ECDSA:
769 					get_keytypes |= KT_ECDSA;
770 					break;
771 				case KEY_RSA:
772 					get_keytypes |= KT_RSA;
773 					break;
774 				case KEY_ED25519:
775 					get_keytypes |= KT_ED25519;
776 					break;
777 				case KEY_XMSS:
778 					get_keytypes |= KT_XMSS;
779 					break;
780 				case KEY_ED25519_SK:
781 					get_keytypes |= KT_ED25519_SK;
782 					break;
783 				case KEY_ECDSA_SK:
784 					get_keytypes |= KT_ECDSA_SK;
785 					break;
786 				case KEY_UNSPEC:
787 				default:
788 					fatal("Unknown key type \"%s\"", tname);
789 				}
790 				tname = strtok(NULL, ",");
791 			}
792 			break;
793 		case '4':
794 			IPv4or6 = AF_INET;
795 			break;
796 		case '6':
797 			IPv4or6 = AF_INET6;
798 			break;
799 		default:
800 			usage();
801 		}
802 	}
803 	if (optind == argc && !fopt_count)
804 		usage();
805 
806 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
807 
808 	maxfd = fdlim_get(1);
809 	if (maxfd < 0)
810 		fatal("%s: fdlim_get: bad value", __progname);
811 	if (maxfd > MAXMAXFD)
812 		maxfd = MAXMAXFD;
813 	if (MAXCON <= 0)
814 		fatal("%s: not enough file descriptors", __progname);
815 	if (maxfd > fdlim_get(0))
816 		fdlim_set(maxfd);
817 	fdcon = xcalloc(maxfd, sizeof(con));
818 	read_wait = xcalloc(maxfd, sizeof(struct pollfd));
819 	for (j = 0; j < maxfd; j++)
820 		read_wait[j].fd = -1;
821 
822 	for (j = 0; j < fopt_count; j++) {
823 		if (argv[j] == NULL)
824 			fp = stdin;
825 		else if ((fp = fopen(argv[j], "r")) == NULL)
826 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
827 
828 		while (getline(&line, &linesize, fp) != -1) {
829 			/* Chomp off trailing whitespace and comments */
830 			if ((cp = strchr(line, '#')) == NULL)
831 				cp = line + strlen(line) - 1;
832 			while (cp >= line) {
833 				if (*cp == ' ' || *cp == '\t' ||
834 				    *cp == '\n' || *cp == '#')
835 					*cp-- = '\0';
836 				else
837 					break;
838 			}
839 
840 			/* Skip empty lines */
841 			if (*line == '\0')
842 				continue;
843 
844 			do_host(line);
845 		}
846 
847 		if (ferror(fp))
848 			fatal("%s: %s: %s", __progname, argv[j], strerror(errno));
849 
850 		fclose(fp);
851 	}
852 	free(line);
853 
854 	while (optind < argc)
855 		do_host(argv[optind++]);
856 
857 	while (ncon > 0)
858 		conloop();
859 
860 	return found_one ? 0 : 1;
861 }
862