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      1 /* $OpenBSD: ssh-keyscan.c,v 1.85 2011/03/15 10:36:02 okan Exp $ */
      2 /*
      3  * Copyright 1995, 1996 by David Mazieres <dm (at) 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 "openbsd-compat/sys-queue.h"
     13 #include <sys/resource.h>
     14 #ifdef HAVE_SYS_TIME_H
     15 # include <sys/time.h>
     16 #endif
     17 
     18 #include <netinet/in.h>
     19 #include <arpa/inet.h>
     20 
     21 #include <openssl/bn.h>
     22 
     23 #include <netdb.h>
     24 #include <errno.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 #define KT_ECDSA	8
     59 
     60 int get_keytypes = KT_RSA;	/* Get only RSA keys by default */
     61 
     62 int hash_hosts = 0;		/* Hash hostname on output */
     63 
     64 #define MAXMAXFD 256
     65 
     66 /* The number of seconds after which to give up on a TCP connection */
     67 int timeout = 5;
     68 
     69 int maxfd;
     70 #define MAXCON (maxfd - 10)
     71 
     72 extern char *__progname;
     73 fd_set *read_wait;
     74 size_t read_wait_nfdset;
     75 int ncon;
     76 int nonfatal_fatal = 0;
     77 jmp_buf kexjmp;
     78 Key *kexjmp_key;
     79 
     80 /*
     81  * Keep a connection structure for each file descriptor.  The state
     82  * associated with file descriptor n is held in fdcon[n].
     83  */
     84 typedef struct Connection {
     85 	u_char c_status;	/* State of connection on this file desc. */
     86 #define CS_UNUSED 0		/* File descriptor unused */
     87 #define CS_CON 1		/* Waiting to connect/read greeting */
     88 #define CS_SIZE 2		/* Waiting to read initial packet size */
     89 #define CS_KEYS 3		/* Waiting to read public key packet */
     90 	int c_fd;		/* Quick lookup: c->c_fd == c - fdcon */
     91 	int c_plen;		/* Packet length field for ssh packet */
     92 	int c_len;		/* Total bytes which must be read. */
     93 	int c_off;		/* Length of data read so far. */
     94 	int c_keytype;		/* Only one of KT_RSA1, KT_DSA, or KT_RSA */
     95 	char *c_namebase;	/* Address to free for c_name and c_namelist */
     96 	char *c_name;		/* Hostname of connection for errors */
     97 	char *c_namelist;	/* Pointer to other possible addresses */
     98 	char *c_output_name;	/* Hostname of connection for output */
     99 	char *c_data;		/* Data read from this fd */
    100 	Kex *c_kex;		/* The key-exchange struct for ssh2 */
    101 	struct timeval c_tv;	/* Time at which connection gets aborted */
    102 	TAILQ_ENTRY(Connection) c_link;	/* List of connections in timeout order. */
    103 } con;
    104 
    105 TAILQ_HEAD(conlist, Connection) tq;	/* Timeout Queue */
    106 con *fdcon;
    107 
    108 static int
    109 fdlim_get(int hard)
    110 {
    111 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
    112 	struct rlimit rlfd;
    113 
    114 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
    115 		return (-1);
    116 	if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
    117 		return SSH_SYSFDMAX;
    118 	else
    119 		return hard ? rlfd.rlim_max : rlfd.rlim_cur;
    120 #else
    121 	return SSH_SYSFDMAX;
    122 #endif
    123 }
    124 
    125 static int
    126 fdlim_set(int lim)
    127 {
    128 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
    129 	struct rlimit rlfd;
    130 #endif
    131 
    132 	if (lim <= 0)
    133 		return (-1);
    134 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
    135 	if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
    136 		return (-1);
    137 	rlfd.rlim_cur = lim;
    138 	if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
    139 		return (-1);
    140 #elif defined (HAVE_SETDTABLESIZE)
    141 	setdtablesize(lim);
    142 #endif
    143 	return (0);
    144 }
    145 
    146 /*
    147  * This is an strsep function that returns a null field for adjacent
    148  * separators.  This is the same as the 4.4BSD strsep, but different from the
    149  * one in the GNU libc.
    150  */
    151 static char *
    152 xstrsep(char **str, const char *delim)
    153 {
    154 	char *s, *e;
    155 
    156 	if (!**str)
    157 		return (NULL);
    158 
    159 	s = *str;
    160 	e = s + strcspn(s, delim);
    161 
    162 	if (*e != '\0')
    163 		*e++ = '\0';
    164 	*str = e;
    165 
    166 	return (s);
    167 }
    168 
    169 /*
    170  * Get the next non-null token (like GNU strsep).  Strsep() will return a
    171  * null token for two adjacent separators, so we may have to loop.
    172  */
    173 static char *
    174 strnnsep(char **stringp, char *delim)
    175 {
    176 	char *tok;
    177 
    178 	do {
    179 		tok = xstrsep(stringp, delim);
    180 	} while (tok && *tok == '\0');
    181 	return (tok);
    182 }
    183 
    184 static Key *
    185 keygrab_ssh1(con *c)
    186 {
    187 	static Key *rsa;
    188 	static Buffer msg;
    189 
    190 	if (rsa == NULL) {
    191 		buffer_init(&msg);
    192 		rsa = key_new(KEY_RSA1);
    193 	}
    194 	buffer_append(&msg, c->c_data, c->c_plen);
    195 	buffer_consume(&msg, 8 - (c->c_plen & 7));	/* padding */
    196 	if (buffer_get_char(&msg) != (int) SSH_SMSG_PUBLIC_KEY) {
    197 		error("%s: invalid packet type", c->c_name);
    198 		buffer_clear(&msg);
    199 		return NULL;
    200 	}
    201 	buffer_consume(&msg, 8);		/* cookie */
    202 
    203 	/* server key */
    204 	(void) buffer_get_int(&msg);
    205 	buffer_get_bignum(&msg, rsa->rsa->e);
    206 	buffer_get_bignum(&msg, rsa->rsa->n);
    207 
    208 	/* host key */
    209 	(void) buffer_get_int(&msg);
    210 	buffer_get_bignum(&msg, rsa->rsa->e);
    211 	buffer_get_bignum(&msg, rsa->rsa->n);
    212 
    213 	buffer_clear(&msg);
    214 
    215 	return (rsa);
    216 }
    217 
    218 static int
    219 hostjump(Key *hostkey)
    220 {
    221 	kexjmp_key = hostkey;
    222 	longjmp(kexjmp, 1);
    223 }
    224 
    225 static int
    226 ssh2_capable(int remote_major, int remote_minor)
    227 {
    228 	switch (remote_major) {
    229 	case 1:
    230 		if (remote_minor == 99)
    231 			return 1;
    232 		break;
    233 	case 2:
    234 		return 1;
    235 	default:
    236 		break;
    237 	}
    238 	return 0;
    239 }
    240 
    241 static Key *
    242 keygrab_ssh2(con *c)
    243 {
    244 	int j;
    245 
    246 	packet_set_connection(c->c_fd, c->c_fd);
    247 	enable_compat20();
    248 	myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = c->c_keytype == KT_DSA?
    249 	    "ssh-dss" : (c->c_keytype == KT_RSA ? "ssh-rsa" :
    250 	    "ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521");
    251 	c->c_kex = kex_setup(myproposal);
    252 	c->c_kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
    253 	c->c_kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
    254 	c->c_kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
    255 	c->c_kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
    256 	c->c_kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
    257 	c->c_kex->verify_host_key = hostjump;
    258 
    259 	if (!(j = setjmp(kexjmp))) {
    260 		nonfatal_fatal = 1;
    261 		dispatch_run(DISPATCH_BLOCK, &c->c_kex->done, c->c_kex);
    262 		fprintf(stderr, "Impossible! dispatch_run() returned!\n");
    263 		exit(1);
    264 	}
    265 	nonfatal_fatal = 0;
    266 	xfree(c->c_kex);
    267 	c->c_kex = NULL;
    268 	packet_close();
    269 
    270 	return j < 0? NULL : kexjmp_key;
    271 }
    272 
    273 static void
    274 keyprint(con *c, Key *key)
    275 {
    276 	char *host = c->c_output_name ? c->c_output_name : c->c_name;
    277 
    278 	if (!key)
    279 		return;
    280 	if (hash_hosts && (host = host_hash(host, NULL, 0)) == NULL)
    281 		fatal("host_hash failed");
    282 
    283 	fprintf(stdout, "%s ", host);
    284 	key_write(key, stdout);
    285 	fputs("\n", stdout);
    286 }
    287 
    288 static int
    289 tcpconnect(char *host)
    290 {
    291 	struct addrinfo hints, *ai, *aitop;
    292 	char strport[NI_MAXSERV];
    293 	int gaierr, s = -1;
    294 
    295 	snprintf(strport, sizeof strport, "%d", ssh_port);
    296 	memset(&hints, 0, sizeof(hints));
    297 	hints.ai_family = IPv4or6;
    298 	hints.ai_socktype = SOCK_STREAM;
    299 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
    300 		fatal("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
    301 	for (ai = aitop; ai; ai = ai->ai_next) {
    302 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
    303 		if (s < 0) {
    304 			error("socket: %s", strerror(errno));
    305 			continue;
    306 		}
    307 		if (set_nonblock(s) == -1)
    308 			fatal("%s: set_nonblock(%d)", __func__, s);
    309 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
    310 		    errno != EINPROGRESS)
    311 			error("connect (`%s'): %s", host, strerror(errno));
    312 		else
    313 			break;
    314 		close(s);
    315 		s = -1;
    316 	}
    317 	freeaddrinfo(aitop);
    318 	return s;
    319 }
    320 
    321 static int
    322 conalloc(char *iname, char *oname, int keytype)
    323 {
    324 	char *namebase, *name, *namelist;
    325 	int s;
    326 
    327 	namebase = namelist = xstrdup(iname);
    328 
    329 	do {
    330 		name = xstrsep(&namelist, ",");
    331 		if (!name) {
    332 			xfree(namebase);
    333 			return (-1);
    334 		}
    335 	} while ((s = tcpconnect(name)) < 0);
    336 
    337 	if (s >= maxfd)
    338 		fatal("conalloc: fdno %d too high", s);
    339 	if (fdcon[s].c_status)
    340 		fatal("conalloc: attempt to reuse fdno %d", s);
    341 
    342 	fdcon[s].c_fd = s;
    343 	fdcon[s].c_status = CS_CON;
    344 	fdcon[s].c_namebase = namebase;
    345 	fdcon[s].c_name = name;
    346 	fdcon[s].c_namelist = namelist;
    347 	fdcon[s].c_output_name = xstrdup(oname);
    348 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
    349 	fdcon[s].c_len = 4;
    350 	fdcon[s].c_off = 0;
    351 	fdcon[s].c_keytype = keytype;
    352 	gettimeofday(&fdcon[s].c_tv, NULL);
    353 	fdcon[s].c_tv.tv_sec += timeout;
    354 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
    355 	FD_SET(s, read_wait);
    356 	ncon++;
    357 	return (s);
    358 }
    359 
    360 static void
    361 confree(int s)
    362 {
    363 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
    364 		fatal("confree: attempt to free bad fdno %d", s);
    365 	close(s);
    366 	xfree(fdcon[s].c_namebase);
    367 	xfree(fdcon[s].c_output_name);
    368 	if (fdcon[s].c_status == CS_KEYS)
    369 		xfree(fdcon[s].c_data);
    370 	fdcon[s].c_status = CS_UNUSED;
    371 	fdcon[s].c_keytype = 0;
    372 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
    373 	FD_CLR(s, read_wait);
    374 	ncon--;
    375 }
    376 
    377 static void
    378 contouch(int s)
    379 {
    380 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
    381 	gettimeofday(&fdcon[s].c_tv, NULL);
    382 	fdcon[s].c_tv.tv_sec += timeout;
    383 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
    384 }
    385 
    386 static int
    387 conrecycle(int s)
    388 {
    389 	con *c = &fdcon[s];
    390 	int ret;
    391 
    392 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
    393 	confree(s);
    394 	return (ret);
    395 }
    396 
    397 static void
    398 congreet(int s)
    399 {
    400 	int n = 0, remote_major = 0, remote_minor = 0;
    401 	char buf[256], *cp;
    402 	char remote_version[sizeof buf];
    403 	size_t bufsiz;
    404 	con *c = &fdcon[s];
    405 
    406 	for (;;) {
    407 		memset(buf, '\0', sizeof(buf));
    408 		bufsiz = sizeof(buf);
    409 		cp = buf;
    410 		while (bufsiz-- &&
    411 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
    412 			if (*cp == '\r')
    413 				*cp = '\n';
    414 			cp++;
    415 		}
    416 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
    417 			break;
    418 	}
    419 	if (n == 0) {
    420 		switch (errno) {
    421 		case EPIPE:
    422 			error("%s: Connection closed by remote host", c->c_name);
    423 			break;
    424 		case ECONNREFUSED:
    425 			break;
    426 		default:
    427 			error("read (%s): %s", c->c_name, strerror(errno));
    428 			break;
    429 		}
    430 		conrecycle(s);
    431 		return;
    432 	}
    433 	if (*cp != '\n' && *cp != '\r') {
    434 		error("%s: bad greeting", c->c_name);
    435 		confree(s);
    436 		return;
    437 	}
    438 	*cp = '\0';
    439 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
    440 	    &remote_major, &remote_minor, remote_version) == 3)
    441 		compat_datafellows(remote_version);
    442 	else
    443 		datafellows = 0;
    444 	if (c->c_keytype != KT_RSA1) {
    445 		if (!ssh2_capable(remote_major, remote_minor)) {
    446 			debug("%s doesn't support ssh2", c->c_name);
    447 			confree(s);
    448 			return;
    449 		}
    450 	} else if (remote_major != 1) {
    451 		debug("%s doesn't support ssh1", c->c_name);
    452 		confree(s);
    453 		return;
    454 	}
    455 	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
    456 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
    457 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
    458 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
    459 	if (n < 0 || (size_t)n >= sizeof(buf)) {
    460 		error("snprintf: buffer too small");
    461 		confree(s);
    462 		return;
    463 	}
    464 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
    465 		error("write (%s): %s", c->c_name, strerror(errno));
    466 		confree(s);
    467 		return;
    468 	}
    469 	if (c->c_keytype != KT_RSA1) {
    470 		keyprint(c, keygrab_ssh2(c));
    471 		confree(s);
    472 		return;
    473 	}
    474 	c->c_status = CS_SIZE;
    475 	contouch(s);
    476 }
    477 
    478 static void
    479 conread(int s)
    480 {
    481 	con *c = &fdcon[s];
    482 	size_t n;
    483 
    484 	if (c->c_status == CS_CON) {
    485 		congreet(s);
    486 		return;
    487 	}
    488 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
    489 	if (n == 0) {
    490 		error("read (%s): %s", c->c_name, strerror(errno));
    491 		confree(s);
    492 		return;
    493 	}
    494 	c->c_off += n;
    495 
    496 	if (c->c_off == c->c_len)
    497 		switch (c->c_status) {
    498 		case CS_SIZE:
    499 			c->c_plen = htonl(c->c_plen);
    500 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
    501 			c->c_off = 0;
    502 			c->c_data = xmalloc(c->c_len);
    503 			c->c_status = CS_KEYS;
    504 			break;
    505 		case CS_KEYS:
    506 			keyprint(c, keygrab_ssh1(c));
    507 			confree(s);
    508 			return;
    509 		default:
    510 			fatal("conread: invalid status %d", c->c_status);
    511 			break;
    512 		}
    513 
    514 	contouch(s);
    515 }
    516 
    517 static void
    518 conloop(void)
    519 {
    520 	struct timeval seltime, now;
    521 	fd_set *r, *e;
    522 	con *c;
    523 	int i;
    524 
    525 	gettimeofday(&now, NULL);
    526 	c = TAILQ_FIRST(&tq);
    527 
    528 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
    529 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
    530 		seltime = c->c_tv;
    531 		seltime.tv_sec -= now.tv_sec;
    532 		seltime.tv_usec -= now.tv_usec;
    533 		if (seltime.tv_usec < 0) {
    534 			seltime.tv_usec += 1000000;
    535 			seltime.tv_sec--;
    536 		}
    537 	} else
    538 		timerclear(&seltime);
    539 
    540 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
    541 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
    542 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
    543 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
    544 
    545 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
    546 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
    547 		;
    548 
    549 	for (i = 0; i < maxfd; i++) {
    550 		if (FD_ISSET(i, e)) {
    551 			error("%s: exception!", fdcon[i].c_name);
    552 			confree(i);
    553 		} else if (FD_ISSET(i, r))
    554 			conread(i);
    555 	}
    556 	xfree(r);
    557 	xfree(e);
    558 
    559 	c = TAILQ_FIRST(&tq);
    560 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
    561 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
    562 		int s = c->c_fd;
    563 
    564 		c = TAILQ_NEXT(c, c_link);
    565 		conrecycle(s);
    566 	}
    567 }
    568 
    569 static void
    570 do_host(char *host)
    571 {
    572 	char *name = strnnsep(&host, " \t\n");
    573 	int j;
    574 
    575 	if (name == NULL)
    576 		return;
    577 	for (j = KT_RSA1; j <= KT_ECDSA; j *= 2) {
    578 		if (get_keytypes & j) {
    579 			while (ncon >= MAXCON)
    580 				conloop();
    581 			conalloc(name, *host ? host : name, j);
    582 		}
    583 	}
    584 }
    585 
    586 void
    587 fatal(const char *fmt,...)
    588 {
    589 	va_list args;
    590 
    591 	va_start(args, fmt);
    592 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
    593 	va_end(args);
    594 	if (nonfatal_fatal)
    595 		longjmp(kexjmp, -1);
    596 	else
    597 		exit(255);
    598 }
    599 
    600 static void
    601 usage(void)
    602 {
    603 	fprintf(stderr,
    604 	    "usage: %s [-46Hv] [-f file] [-p port] [-T timeout] [-t type]\n"
    605 	    "\t\t   [host | addrlist namelist] ...\n",
    606 	    __progname);
    607 	exit(1);
    608 }
    609 
    610 int
    611 main(int argc, char **argv)
    612 {
    613 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
    614 	int opt, fopt_count = 0, j;
    615 	char *tname, *cp, line[NI_MAXHOST];
    616 	FILE *fp;
    617 	u_long linenum;
    618 
    619 	extern int optind;
    620 	extern char *optarg;
    621 
    622 	__progname = ssh_get_progname(argv[0]);
    623 	seed_rng();
    624 	TAILQ_INIT(&tq);
    625 
    626 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
    627 	sanitise_stdfd();
    628 
    629 	if (argc <= 1)
    630 		usage();
    631 
    632 	while ((opt = getopt(argc, argv, "Hv46p:T:t:f:")) != -1) {
    633 		switch (opt) {
    634 		case 'H':
    635 			hash_hosts = 1;
    636 			break;
    637 		case 'p':
    638 			ssh_port = a2port(optarg);
    639 			if (ssh_port <= 0) {
    640 				fprintf(stderr, "Bad port '%s'\n", optarg);
    641 				exit(1);
    642 			}
    643 			break;
    644 		case 'T':
    645 			timeout = convtime(optarg);
    646 			if (timeout == -1 || timeout == 0) {
    647 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
    648 				usage();
    649 			}
    650 			break;
    651 		case 'v':
    652 			if (!debug_flag) {
    653 				debug_flag = 1;
    654 				log_level = SYSLOG_LEVEL_DEBUG1;
    655 			}
    656 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
    657 				log_level++;
    658 			else
    659 				fatal("Too high debugging level.");
    660 			break;
    661 		case 'f':
    662 			if (strcmp(optarg, "-") == 0)
    663 				optarg = NULL;
    664 			argv[fopt_count++] = optarg;
    665 			break;
    666 		case 't':
    667 			get_keytypes = 0;
    668 			tname = strtok(optarg, ",");
    669 			while (tname) {
    670 				int type = key_type_from_name(tname);
    671 				switch (type) {
    672 				case KEY_RSA1:
    673 					get_keytypes |= KT_RSA1;
    674 					break;
    675 				case KEY_DSA:
    676 					get_keytypes |= KT_DSA;
    677 					break;
    678 				case KEY_ECDSA:
    679 					get_keytypes |= KT_ECDSA;
    680 					break;
    681 				case KEY_RSA:
    682 					get_keytypes |= KT_RSA;
    683 					break;
    684 				case KEY_UNSPEC:
    685 					fatal("unknown key type %s", tname);
    686 				}
    687 				tname = strtok(NULL, ",");
    688 			}
    689 			break;
    690 		case '4':
    691 			IPv4or6 = AF_INET;
    692 			break;
    693 		case '6':
    694 			IPv4or6 = AF_INET6;
    695 			break;
    696 		case '?':
    697 		default:
    698 			usage();
    699 		}
    700 	}
    701 	if (optind == argc && !fopt_count)
    702 		usage();
    703 
    704 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
    705 
    706 	maxfd = fdlim_get(1);
    707 	if (maxfd < 0)
    708 		fatal("%s: fdlim_get: bad value", __progname);
    709 	if (maxfd > MAXMAXFD)
    710 		maxfd = MAXMAXFD;
    711 	if (MAXCON <= 0)
    712 		fatal("%s: not enough file descriptors", __progname);
    713 	if (maxfd > fdlim_get(0))
    714 		fdlim_set(maxfd);
    715 	fdcon = xcalloc(maxfd, sizeof(con));
    716 
    717 	read_wait_nfdset = howmany(maxfd, NFDBITS);
    718 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
    719 
    720 	for (j = 0; j < fopt_count; j++) {
    721 		if (argv[j] == NULL)
    722 			fp = stdin;
    723 		else if ((fp = fopen(argv[j], "r")) == NULL)
    724 			fatal("%s: %s: %s", __progname, argv[j],
    725 			    strerror(errno));
    726 		linenum = 0;
    727 
    728 		while (read_keyfile_line(fp,
    729 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
    730 		    &linenum) != -1) {
    731 			/* Chomp off trailing whitespace and comments */
    732 			if ((cp = strchr(line, '#')) == NULL)
    733 				cp = line + strlen(line) - 1;
    734 			while (cp >= line) {
    735 				if (*cp == ' ' || *cp == '\t' ||
    736 				    *cp == '\n' || *cp == '#')
    737 					*cp-- = '\0';
    738 				else
    739 					break;
    740 			}
    741 
    742 			/* Skip empty lines */
    743 			if (*line == '\0')
    744 				continue;
    745 
    746 			do_host(line);
    747 		}
    748 
    749 		if (ferror(fp))
    750 			fatal("%s: %s: %s", __progname, argv[j],
    751 			    strerror(errno));
    752 
    753 		fclose(fp);
    754 	}
    755 
    756 	while (optind < argc)
    757 		do_host(argv[optind++]);
    758 
    759 	while (ncon > 0)
    760 		conloop();
    761 
    762 	return (0);
    763 }
    764