Home | History | Annotate | Download | only in openssh
      1 /* $OpenBSD: ssh-keyscan.c,v 1.109 2017/03/10 04:26:06 djm 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 <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 (at) openssh.com" : "ssh-dss";
    275 		break;
    276 	case KT_RSA:
    277 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
    278 		    "ssh-rsa-cert-v01 (at) openssh.com" : "ssh-rsa";
    279 		break;
    280 	case KT_ED25519:
    281 		myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
    282 		    "ssh-ed25519-cert-v01 (at) 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 (at) openssh.com,"
    287 		    "ecdsa-sha2-nistp384-cert-v01 (at) openssh.com,"
    288 		    "ecdsa-sha2-nistp521-cert-v01 (at) 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 
    323 static void
    324 keyprint_one(const char *host, struct sshkey *key)
    325 {
    326 	char *hostport;
    327 	const char *known_host, *hashed;
    328 
    329 	hostport = put_host_port(host, ssh_port);
    330 	lowercase(hostport);
    331 	if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
    332 		fatal("host_hash failed");
    333 	known_host = hash_hosts ? hashed : hostport;
    334 	if (!get_cert)
    335 		fprintf(stdout, "%s ", known_host);
    336 	sshkey_write(key, stdout);
    337 	fputs("\n", stdout);
    338 	free(hostport);
    339 }
    340 
    341 static void
    342 keyprint(con *c, struct sshkey *key)
    343 {
    344 	char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
    345 	char *host, *ohosts;
    346 
    347 	if (key == NULL)
    348 		return;
    349 	if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
    350 		keyprint_one(hosts, key);
    351 		return;
    352 	}
    353 	ohosts = hosts = xstrdup(hosts);
    354 	while ((host = strsep(&hosts, ",")) != NULL)
    355 		keyprint_one(host, key);
    356 	free(ohosts);
    357 }
    358 
    359 static int
    360 tcpconnect(char *host)
    361 {
    362 	struct addrinfo hints, *ai, *aitop;
    363 	char strport[NI_MAXSERV];
    364 	int gaierr, s = -1;
    365 
    366 	snprintf(strport, sizeof strport, "%d", ssh_port);
    367 	memset(&hints, 0, sizeof(hints));
    368 	hints.ai_family = IPv4or6;
    369 	hints.ai_socktype = SOCK_STREAM;
    370 	if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
    371 		error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
    372 		return -1;
    373 	}
    374 	for (ai = aitop; ai; ai = ai->ai_next) {
    375 		s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
    376 		if (s < 0) {
    377 			error("socket: %s", strerror(errno));
    378 			continue;
    379 		}
    380 		if (set_nonblock(s) == -1)
    381 			fatal("%s: set_nonblock(%d)", __func__, s);
    382 		if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
    383 		    errno != EINPROGRESS)
    384 			error("connect (`%s'): %s", host, strerror(errno));
    385 		else
    386 			break;
    387 		close(s);
    388 		s = -1;
    389 	}
    390 	freeaddrinfo(aitop);
    391 	return s;
    392 }
    393 
    394 static int
    395 conalloc(char *iname, char *oname, int keytype)
    396 {
    397 	char *namebase, *name, *namelist;
    398 	int s;
    399 
    400 	namebase = namelist = xstrdup(iname);
    401 
    402 	do {
    403 		name = xstrsep(&namelist, ",");
    404 		if (!name) {
    405 			free(namebase);
    406 			return (-1);
    407 		}
    408 	} while ((s = tcpconnect(name)) < 0);
    409 
    410 	if (s >= maxfd)
    411 		fatal("conalloc: fdno %d too high", s);
    412 	if (fdcon[s].c_status)
    413 		fatal("conalloc: attempt to reuse fdno %d", s);
    414 
    415 	debug3("%s: oname %s kt %d", __func__, oname, keytype);
    416 	fdcon[s].c_fd = s;
    417 	fdcon[s].c_status = CS_CON;
    418 	fdcon[s].c_namebase = namebase;
    419 	fdcon[s].c_name = name;
    420 	fdcon[s].c_namelist = namelist;
    421 	fdcon[s].c_output_name = xstrdup(oname);
    422 	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
    423 	fdcon[s].c_len = 4;
    424 	fdcon[s].c_off = 0;
    425 	fdcon[s].c_keytype = keytype;
    426 	gettimeofday(&fdcon[s].c_tv, NULL);
    427 	fdcon[s].c_tv.tv_sec += timeout;
    428 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
    429 	FD_SET(s, read_wait);
    430 	ncon++;
    431 	return (s);
    432 }
    433 
    434 static void
    435 confree(int s)
    436 {
    437 	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
    438 		fatal("confree: attempt to free bad fdno %d", s);
    439 	close(s);
    440 	free(fdcon[s].c_namebase);
    441 	free(fdcon[s].c_output_name);
    442 	if (fdcon[s].c_status == CS_KEYS)
    443 		free(fdcon[s].c_data);
    444 	fdcon[s].c_status = CS_UNUSED;
    445 	fdcon[s].c_keytype = 0;
    446 	if (fdcon[s].c_ssh) {
    447 		ssh_packet_close(fdcon[s].c_ssh);
    448 		free(fdcon[s].c_ssh);
    449 		fdcon[s].c_ssh = NULL;
    450 	}
    451 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
    452 	FD_CLR(s, read_wait);
    453 	ncon--;
    454 }
    455 
    456 static void
    457 contouch(int s)
    458 {
    459 	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
    460 	gettimeofday(&fdcon[s].c_tv, NULL);
    461 	fdcon[s].c_tv.tv_sec += timeout;
    462 	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
    463 }
    464 
    465 static int
    466 conrecycle(int s)
    467 {
    468 	con *c = &fdcon[s];
    469 	int ret;
    470 
    471 	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
    472 	confree(s);
    473 	return (ret);
    474 }
    475 
    476 static void
    477 congreet(int s)
    478 {
    479 	int n = 0, remote_major = 0, remote_minor = 0;
    480 	char buf[256], *cp;
    481 	char remote_version[sizeof buf];
    482 	size_t bufsiz;
    483 	con *c = &fdcon[s];
    484 
    485 	for (;;) {
    486 		memset(buf, '\0', sizeof(buf));
    487 		bufsiz = sizeof(buf);
    488 		cp = buf;
    489 		while (bufsiz-- &&
    490 		    (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
    491 			if (*cp == '\r')
    492 				*cp = '\n';
    493 			cp++;
    494 		}
    495 		if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
    496 			break;
    497 	}
    498 	if (n == 0) {
    499 		switch (errno) {
    500 		case EPIPE:
    501 			error("%s: Connection closed by remote host", c->c_name);
    502 			break;
    503 		case ECONNREFUSED:
    504 			break;
    505 		default:
    506 			error("read (%s): %s", c->c_name, strerror(errno));
    507 			break;
    508 		}
    509 		conrecycle(s);
    510 		return;
    511 	}
    512 	if (*cp != '\n' && *cp != '\r') {
    513 		error("%s: bad greeting", c->c_name);
    514 		confree(s);
    515 		return;
    516 	}
    517 	*cp = '\0';
    518 	if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
    519 		fatal("ssh_packet_set_connection failed");
    520 	ssh_packet_set_timeout(c->c_ssh, timeout, 1);
    521 	ssh_set_app_data(c->c_ssh, c);	/* back link */
    522 	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
    523 	    &remote_major, &remote_minor, remote_version) == 3)
    524 		c->c_ssh->compat = compat_datafellows(remote_version);
    525 	else
    526 		c->c_ssh->compat = 0;
    527 	if (c->c_keytype != KT_RSA1) {
    528 		if (!ssh2_capable(remote_major, remote_minor)) {
    529 			debug("%s doesn't support ssh2", c->c_name);
    530 			confree(s);
    531 			return;
    532 		}
    533 	} else if (remote_major != 1) {
    534 		debug("%s doesn't support ssh1", c->c_name);
    535 		confree(s);
    536 		return;
    537 	}
    538 	fprintf(stderr, "# %s:%d %s\n", c->c_name, ssh_port, chop(buf));
    539 	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
    540 	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
    541 	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
    542 	if (n < 0 || (size_t)n >= sizeof(buf)) {
    543 		error("snprintf: buffer too small");
    544 		confree(s);
    545 		return;
    546 	}
    547 	if (atomicio(vwrite, s, buf, n) != (size_t)n) {
    548 		error("write (%s): %s", c->c_name, strerror(errno));
    549 		confree(s);
    550 		return;
    551 	}
    552 	if (c->c_keytype != KT_RSA1) {
    553 		keygrab_ssh2(c);
    554 		confree(s);
    555 		return;
    556 	}
    557 	c->c_status = CS_SIZE;
    558 	contouch(s);
    559 }
    560 
    561 static void
    562 conread(int s)
    563 {
    564 	con *c = &fdcon[s];
    565 	size_t n;
    566 
    567 	if (c->c_status == CS_CON) {
    568 		congreet(s);
    569 		return;
    570 	}
    571 	n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
    572 	if (n == 0) {
    573 		error("read (%s): %s", c->c_name, strerror(errno));
    574 		confree(s);
    575 		return;
    576 	}
    577 	c->c_off += n;
    578 
    579 	if (c->c_off == c->c_len)
    580 		switch (c->c_status) {
    581 		case CS_SIZE:
    582 			c->c_plen = htonl(c->c_plen);
    583 			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
    584 			c->c_off = 0;
    585 			c->c_data = xmalloc(c->c_len);
    586 			c->c_status = CS_KEYS;
    587 			break;
    588 #ifdef WITH_SSH1
    589 		case CS_KEYS:
    590 			keyprint(c, keygrab_ssh1(c));
    591 			confree(s);
    592 			return;
    593 #endif
    594 		default:
    595 			fatal("conread: invalid status %d", c->c_status);
    596 			break;
    597 		}
    598 
    599 	contouch(s);
    600 }
    601 
    602 static void
    603 conloop(void)
    604 {
    605 	struct timeval seltime, now;
    606 	fd_set *r, *e;
    607 	con *c;
    608 	int i;
    609 
    610 	gettimeofday(&now, NULL);
    611 	c = TAILQ_FIRST(&tq);
    612 
    613 	if (c && (c->c_tv.tv_sec > now.tv_sec ||
    614 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
    615 		seltime = c->c_tv;
    616 		seltime.tv_sec -= now.tv_sec;
    617 		seltime.tv_usec -= now.tv_usec;
    618 		if (seltime.tv_usec < 0) {
    619 			seltime.tv_usec += 1000000;
    620 			seltime.tv_sec--;
    621 		}
    622 	} else
    623 		timerclear(&seltime);
    624 
    625 	r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
    626 	e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
    627 	memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
    628 	memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
    629 
    630 	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
    631 	    (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
    632 		;
    633 
    634 	for (i = 0; i < maxfd; i++) {
    635 		if (FD_ISSET(i, e)) {
    636 			error("%s: exception!", fdcon[i].c_name);
    637 			confree(i);
    638 		} else if (FD_ISSET(i, r))
    639 			conread(i);
    640 	}
    641 	free(r);
    642 	free(e);
    643 
    644 	c = TAILQ_FIRST(&tq);
    645 	while (c && (c->c_tv.tv_sec < now.tv_sec ||
    646 	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
    647 		int s = c->c_fd;
    648 
    649 		c = TAILQ_NEXT(c, c_link);
    650 		conrecycle(s);
    651 	}
    652 }
    653 
    654 static void
    655 do_host(char *host)
    656 {
    657 	char *name = strnnsep(&host, " \t\n");
    658 	int j;
    659 
    660 	if (name == NULL)
    661 		return;
    662 	for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
    663 		if (get_keytypes & j) {
    664 			while (ncon >= MAXCON)
    665 				conloop();
    666 			conalloc(name, *host ? host : name, j);
    667 		}
    668 	}
    669 }
    670 
    671 void
    672 fatal(const char *fmt,...)
    673 {
    674 	va_list args;
    675 
    676 	va_start(args, fmt);
    677 	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
    678 	va_end(args);
    679 	exit(255);
    680 }
    681 
    682 static void
    683 usage(void)
    684 {
    685 	fprintf(stderr,
    686 	    "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
    687 	    "\t\t   [host | addrlist namelist] ...\n",
    688 	    __progname);
    689 	exit(1);
    690 }
    691 
    692 int
    693 main(int argc, char **argv)
    694 {
    695 	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
    696 	int opt, fopt_count = 0, j;
    697 	char *tname, *cp, line[NI_MAXHOST];
    698 	FILE *fp;
    699 	u_long linenum;
    700 
    701 	extern int optind;
    702 	extern char *optarg;
    703 
    704 	ssh_malloc_init();	/* must be called before any mallocs */
    705 	__progname = ssh_get_progname(argv[0]);
    706 	seed_rng();
    707 	TAILQ_INIT(&tq);
    708 
    709 	/* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
    710 	sanitise_stdfd();
    711 
    712 	if (argc <= 1)
    713 		usage();
    714 
    715 	while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
    716 		switch (opt) {
    717 		case 'H':
    718 			hash_hosts = 1;
    719 			break;
    720 		case 'c':
    721 			get_cert = 1;
    722 			break;
    723 		case 'p':
    724 			ssh_port = a2port(optarg);
    725 			if (ssh_port <= 0) {
    726 				fprintf(stderr, "Bad port '%s'\n", optarg);
    727 				exit(1);
    728 			}
    729 			break;
    730 		case 'T':
    731 			timeout = convtime(optarg);
    732 			if (timeout == -1 || timeout == 0) {
    733 				fprintf(stderr, "Bad timeout '%s'\n", optarg);
    734 				usage();
    735 			}
    736 			break;
    737 		case 'v':
    738 			if (!debug_flag) {
    739 				debug_flag = 1;
    740 				log_level = SYSLOG_LEVEL_DEBUG1;
    741 			}
    742 			else if (log_level < SYSLOG_LEVEL_DEBUG3)
    743 				log_level++;
    744 			else
    745 				fatal("Too high debugging level.");
    746 			break;
    747 		case 'f':
    748 			if (strcmp(optarg, "-") == 0)
    749 				optarg = NULL;
    750 			argv[fopt_count++] = optarg;
    751 			break;
    752 		case 't':
    753 			get_keytypes = 0;
    754 			tname = strtok(optarg, ",");
    755 			while (tname) {
    756 				int type = sshkey_type_from_name(tname);
    757 
    758 				switch (type) {
    759 #ifdef WITH_SSH1
    760 				case KEY_RSA1:
    761 					get_keytypes |= KT_RSA1;
    762 					break;
    763 #endif
    764 				case KEY_DSA:
    765 					get_keytypes |= KT_DSA;
    766 					break;
    767 				case KEY_ECDSA:
    768 					get_keytypes |= KT_ECDSA;
    769 					break;
    770 				case KEY_RSA:
    771 					get_keytypes |= KT_RSA;
    772 					break;
    773 				case KEY_ED25519:
    774 					get_keytypes |= KT_ED25519;
    775 					break;
    776 				case KEY_UNSPEC:
    777 				default:
    778 					fatal("Unknown key type \"%s\"", tname);
    779 				}
    780 				tname = strtok(NULL, ",");
    781 			}
    782 			break;
    783 		case '4':
    784 			IPv4or6 = AF_INET;
    785 			break;
    786 		case '6':
    787 			IPv4or6 = AF_INET6;
    788 			break;
    789 		case '?':
    790 		default:
    791 			usage();
    792 		}
    793 	}
    794 	if (optind == argc && !fopt_count)
    795 		usage();
    796 
    797 	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
    798 
    799 	maxfd = fdlim_get(1);
    800 	if (maxfd < 0)
    801 		fatal("%s: fdlim_get: bad value", __progname);
    802 	if (maxfd > MAXMAXFD)
    803 		maxfd = MAXMAXFD;
    804 	if (MAXCON <= 0)
    805 		fatal("%s: not enough file descriptors", __progname);
    806 	if (maxfd > fdlim_get(0))
    807 		fdlim_set(maxfd);
    808 	fdcon = xcalloc(maxfd, sizeof(con));
    809 
    810 	read_wait_nfdset = howmany(maxfd, NFDBITS);
    811 	read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
    812 
    813 	for (j = 0; j < fopt_count; j++) {
    814 		if (argv[j] == NULL)
    815 			fp = stdin;
    816 		else if ((fp = fopen(argv[j], "r")) == NULL)
    817 			fatal("%s: %s: %s", __progname, argv[j],
    818 			    strerror(errno));
    819 		linenum = 0;
    820 
    821 		while (read_keyfile_line(fp,
    822 		    argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
    823 		    &linenum) != -1) {
    824 			/* Chomp off trailing whitespace and comments */
    825 			if ((cp = strchr(line, '#')) == NULL)
    826 				cp = line + strlen(line) - 1;
    827 			while (cp >= line) {
    828 				if (*cp == ' ' || *cp == '\t' ||
    829 				    *cp == '\n' || *cp == '#')
    830 					*cp-- = '\0';
    831 				else
    832 					break;
    833 			}
    834 
    835 			/* Skip empty lines */
    836 			if (*line == '\0')
    837 				continue;
    838 
    839 			do_host(line);
    840 		}
    841 
    842 		if (ferror(fp))
    843 			fatal("%s: %s: %s", __progname, argv[j],
    844 			    strerror(errno));
    845 
    846 		fclose(fp);
    847 	}
    848 
    849 	while (optind < argc)
    850 		do_host(argv[optind++]);
    851 
    852 	while (ncon > 0)
    853 		conloop();
    854 
    855 	return (0);
    856 }
    857