ssh-keyscan.c

OpenSSL Source code for SFTP, SSH, and many others

}

static int
conalloc(char *iname, char *oname, int keytype)
{
	int s;
	char *namebase, *name, *namelist;

	namebase = namelist = xstrdup(iname);

	do {
		name = xstrsep(&namelist, ",");
		if (!name) {
			xfree(namebase);
			return (-1);
		}
	} while ((s = tcpconnect(name)) < 0);

	if (s >= maxfd)
		fatal("conalloc: fdno %d too high", s);
	if (fdcon[s].c_status)
		fatal("conalloc: attempt to reuse fdno %d", s);

	fdcon[s].c_fd = s;
	fdcon[s].c_status = CS_CON;
	fdcon[s].c_namebase = namebase;
	fdcon[s].c_name = name;
	fdcon[s].c_namelist = namelist;
	fdcon[s].c_output_name = xstrdup(oname);
	fdcon[s].c_data = (char *) &fdcon[s].c_plen;
	fdcon[s].c_len = 4;
	fdcon[s].c_off = 0;
	fdcon[s].c_keytype = keytype;
	gettimeofday(&fdcon[s].c_tv, NULL);
	fdcon[s].c_tv.tv_sec += timeout;
	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
	FD_SET(s, read_wait);
	ncon++;
	return (s);
}

static void
confree(int s)
{
	if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
		fatal("confree: attempt to free bad fdno %d", s);
	close(s);
	xfree(fdcon[s].c_namebase);
	xfree(fdcon[s].c_output_name);
	if (fdcon[s].c_status == CS_KEYS)
		xfree(fdcon[s].c_data);
	fdcon[s].c_status = CS_UNUSED;
	fdcon[s].c_keytype = 0;
	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
	FD_CLR(s, read_wait);
	ncon--;
}

static void
contouch(int s)
{
	TAILQ_REMOVE(&tq, &fdcon[s], c_link);
	gettimeofday(&fdcon[s].c_tv, NULL);
	fdcon[s].c_tv.tv_sec += timeout;
	TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
}

static int
conrecycle(int s)
{
	int ret;
	con *c = &fdcon[s];

	ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
	confree(s);
	return (ret);
}

static void
congreet(int s)
{
	char buf[256], *cp;
	char remote_version[sizeof buf];
	size_t bufsiz;
	int remote_major, remote_minor, n = 0;
	con *c = &fdcon[s];

	bufsiz = sizeof(buf);
	cp = buf;
	while (bufsiz-- && (n = read(s, cp, 1)) == 1 && *cp != '\n') {
		if (*cp == '\r')
			*cp = '\n';
		cp++;
	}
	if (n < 0) {
		if (errno != ECONNREFUSED)
			error("read (%s): %s", c->c_name, strerror(errno));
		conrecycle(s);
		return;
	}
	if (n == 0) {
		error("%s: Connection closed by remote host", c->c_name);
		conrecycle(s);
		return;
	}
	if (*cp != '\n' && *cp != '\r') {
		error("%s: bad greeting", c->c_name);
		confree(s);
		return;
	}
	*cp = '\0';
	if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
	    &remote_major, &remote_minor, remote_version) == 3)
		compat_datafellows(remote_version);
	else
		datafellows = 0;
	if (c->c_keytype != KT_RSA1) {
		if (!ssh2_capable(remote_major, remote_minor)) {
			debug("%s doesn't support ssh2", c->c_name);
			confree(s);
			return;
		}
	} else if (remote_major != 1) {
		debug("%s doesn't support ssh1", c->c_name);
		confree(s);
		return;
	}
	fprintf(stderr, "# %s %s\n", c->c_name, chop(buf));
	n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
	    c->c_keytype == KT_RSA1? PROTOCOL_MAJOR_1 : PROTOCOL_MAJOR_2,
	    c->c_keytype == KT_RSA1? PROTOCOL_MINOR_1 : PROTOCOL_MINOR_2);
	if (atomicio(write, s, buf, n) != n) {
		error("write (%s): %s", c->c_name, strerror(errno));
		confree(s);
		return;
	}
	if (c->c_keytype != KT_RSA1) {
		keyprint(c, keygrab_ssh2(c));
		confree(s);
		return;
	}
	c->c_status = CS_SIZE;
	contouch(s);
}

static void
conread(int s)
{
	int n;
	con *c = &fdcon[s];

	if (c->c_status == CS_CON) {
		congreet(s);
		return;
	}
	n = read(s, c->c_data + c->c_off, c->c_len - c->c_off);
	if (n < 0) {
		error("read (%s): %s", c->c_name, strerror(errno));
		confree(s);
		return;
	}
	c->c_off += n;

	if (c->c_off == c->c_len)
		switch (c->c_status) {
		case CS_SIZE:
			c->c_plen = htonl(c->c_plen);
			c->c_len = c->c_plen + 8 - (c->c_plen & 7);
			c->c_off = 0;
			c->c_data = xmalloc(c->c_len);
			c->c_status = CS_KEYS;
			break;
		case CS_KEYS:
			keyprint(c, keygrab_ssh1(c));
			confree(s);
			return;
			break;
		default:
			fatal("conread: invalid status %d", c->c_status);
			break;
		}

	contouch(s);
}

static void
conloop(void)
{
	fd_set *r, *e;
	struct timeval seltime, now;
	int i;
	con *c;

	gettimeofday(&now, NULL);
	c = TAILQ_FIRST(&tq);

	if (c && (c->c_tv.tv_sec > now.tv_sec ||
	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
		seltime = c->c_tv;
		seltime.tv_sec -= now.tv_sec;
		seltime.tv_usec -= now.tv_usec;
		if (seltime.tv_usec < 0) {
			seltime.tv_usec += 1000000;
			seltime.tv_sec--;
		}
	} else
		seltime.tv_sec = seltime.tv_usec = 0;

	r = xmalloc(read_wait_size);
	memcpy(r, read_wait, read_wait_size);
	e = xmalloc(read_wait_size);
	memcpy(e, read_wait, read_wait_size);

	while (select(maxfd, r, NULL, e, &seltime) == -1 &&
	    (errno == EAGAIN || errno == EINTR))
		;

	for (i = 0; i < maxfd; i++) {
		if (FD_ISSET(i, e)) {
			error("%s: exception!", fdcon[i].c_name);
			confree(i);
		} else if (FD_ISSET(i, r))
			conread(i);
	}
	xfree(r);
	xfree(e);

	c = TAILQ_FIRST(&tq);
	while (c && (c->c_tv.tv_sec < now.tv_sec ||
	    (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
		int s = c->c_fd;

		c = TAILQ_NEXT(c, c_link);
		conrecycle(s);
	}
}

static void
do_host(char *host)
{
	char *name = strnnsep(&host, " \t\n");
	int j;

	if (name == NULL)
		return;
	for (j = KT_RSA1; j <= KT_RSA; j *= 2) {
		if (get_keytypes & j) {
			while (ncon >= MAXCON)
				conloop();
			conalloc(name, *host ? host : name, j);
		}
	}
}

void
fatal(const char *fmt,...)
{
	va_list args;
	va_start(args, fmt);
	do_log(SYSLOG_LEVEL_FATAL, fmt, args);
	va_end(args);
	if (nonfatal_fatal)
		longjmp(kexjmp, -1);
	else
		fatal_cleanup();
}

static void
usage(void)
{
	fprintf(stderr, "Usage: %s [options] host ...\n",
	    __progname);
	fprintf(stderr, "Options:\n");
	fprintf(stderr, "  -f file     Read hosts or addresses from file.\n");
	fprintf(stderr, "  -p port     Connect to the specified port.\n");
	fprintf(stderr, "  -t keytype  Specify the host key type.\n");
	fprintf(stderr, "  -T timeout  Set connection timeout.\n");
	fprintf(stderr, "  -v          Verbose; display verbose debugging messages.\n");
	fprintf(stderr, "  -4          Use IPv4 only.\n");
	fprintf(stderr, "  -6          Use IPv6 only.\n");
	exit(1);
}

int
main(int argc, char **argv)
{
	int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
	int opt, fopt_count = 0;
	char *tname;

	extern int optind;
	extern char *optarg;

	__progname = get_progname(argv[0]);
	init_rng();
	seed_rng();
	TAILQ_INIT(&tq);

	if (argc <= 1)
		usage();

	while ((opt = getopt(argc, argv, "v46p:T:t:f:")) != -1) {
		switch (opt) {
		case 'p':
			ssh_port = a2port(optarg);
			if (ssh_port == 0) {
				fprintf(stderr, "Bad port '%s'\n", optarg);
				exit(1);
			}
			break;
		case 'T':
			timeout = atoi(optarg);
			if (timeout <= 0)
				usage();
			break;
		case 'v':
			if (!debug_flag) {
				debug_flag = 1;
				log_level = SYSLOG_LEVEL_DEBUG1;
			}
			else if (log_level < SYSLOG_LEVEL_DEBUG3)
				log_level++;
			else
				fatal("Too high debugging level.");
			break;
		case 'f':
			if (strcmp(optarg, "-") == 0)
				optarg = NULL;
			argv[fopt_count++] = optarg;
			break;
		case 't':
			get_keytypes = 0;
			tname = strtok(optarg, ",");
			while (tname) {
				int type = key_type_from_name(tname);
				switch (type) {
				case KEY_RSA1:
					get_keytypes |= KT_RSA1;
					break;
				case KEY_DSA:
					get_keytypes |= KT_DSA;
					break;
				case KEY_RSA:
					get_keytypes |= KT_RSA;
					break;
				case KEY_UNSPEC:
					fatal("unknown key type %s", tname);
				}
				tname = strtok(NULL, ",");
			}
			break;
		case '4':
			IPv4or6 = AF_INET;
			break;
		case '6':
			IPv4or6 = AF_INET6;
			break;
		case '?':
		default:
			usage();
		}
	}
	if (optind == argc && !fopt_count)
		usage();

	log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);

	maxfd = fdlim_get(1);
	if (maxfd < 0)
		fatal("%s: fdlim_get: bad value", __progname);
	if (maxfd > MAXMAXFD)
		maxfd = MAXMAXFD;
	if (MAXCON <= 0)
		fatal("%s: not enough file descriptors", __progname);
	if (maxfd > fdlim_get(0))
		fdlim_set(maxfd);
	fdcon = xmalloc(maxfd * sizeof(con));
	memset(fdcon, 0, maxfd * sizeof(con));

	read_wait_size = howmany(maxfd, NFDBITS) * sizeof(fd_mask);
	read_wait = xmalloc(read_wait_size);
	memset(read_wait, 0, read_wait_size);

	if (fopt_count) {
		Linebuf *lb;
		char *line;
		int j;

		for (j = 0; j < fopt_count; j++) {
			lb = Linebuf_alloc(argv[j], error);
			if (!lb)
				continue;
			while ((line = Linebuf_getline(lb)) != NULL)
				do_host(line);
			Linebuf_free(lb);
		}
	}

	while (optind < argc)
		do_host(argv[optind++]);

	while (ncon > 0)
		conloop();

	return (0);
}