1 /* $OpenBSD: ssh-keyscan.c,v 1.109 2017/03/10 04:26:06 djm Exp $ */
3 * Copyright 1995, 1996 by David Mazieres <dm@lcs.mit.edu>.
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.
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>
19 #include <netinet/in.h>
20 #include <arpa/inet.h>
22 #include <openssl/bn.h>
41 #include "myproposal.h"
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;
55 int ssh_port = SSH_DEFAULT_PORT;
64 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
66 int hash_hosts = 0; /* Hash hostname on output */
70 /* The number of seconds after which to give up on a TCP connection */
74 #define MAXCON (maxfd - 10)
76 extern char *__progname;
78 size_t read_wait_nfdset;
81 struct ssh *active_state = NULL; /* XXX needed for linking */
84 * Keep a connection structure for each file descriptor. The state
85 * associated with file descriptor n is held in fdcon[n].
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. */
109 TAILQ_HEAD(conlist, Connection) tq; /* Timeout Queue */
112 static void keyprint(con *c, struct sshkey *key);
117 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
120 if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
122 if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
125 return hard ? rlfd.rlim_max : rlfd.rlim_cur;
134 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
140 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
141 if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
144 if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
146 #elif defined (HAVE_SETDTABLESIZE)
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.
158 xstrsep(char **str, const char *delim)
166 e = s + strcspn(s, delim);
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.
180 strnnsep(char **stringp, char *delim)
185 tok = xstrsep(stringp, delim);
186 } while (tok && *tok == '\0');
191 static struct sshkey *
194 static struct sshkey *rsa;
195 static struct sshbuf *msg;
200 if ((rsa = sshkey_new(KEY_RSA1)) == NULL) {
201 error("%s: sshkey_new failed", __func__);
204 if ((msg = sshbuf_new()) == NULL)
205 fatal("%s: sshbuf_new failed", __func__);
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)
211 if (type != (int) SSH_SMSG_PUBLIC_KEY) {
212 error("%s: invalid packet type", c->c_name);
216 if ((r = sshbuf_consume(msg, 8)) != 0 || /* cookie */
218 (r = sshbuf_get_u32(msg, NULL)) != 0 ||
219 (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
220 (r = sshbuf_get_bignum1(msg, NULL)) != 0 ||
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) {
226 error("%s: buffer error: %s", __func__, ssh_err(r));
238 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
242 if ((c = ssh_get_app_data(ssh)) != NULL)
243 keyprint(c, hostkey);
244 /* always abort key exchange */
249 ssh2_capable(int remote_major, int remote_minor)
251 switch (remote_major) {
253 if (remote_minor == 99)
267 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
271 switch (c->c_keytype) {
273 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
274 "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
277 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
278 "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
281 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
282 "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
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";
294 fatal("unknown key type %d", c->c_keytype);
297 if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
299 fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
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;
314 c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
315 ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
317 * do the key-exchange until an error occurs or until
318 * the key_print_wrapper() callback sets c_done.
320 ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done, c->c_ssh);
324 keyprint_one(const char *host, struct sshkey *key)
327 const char *known_host, *hashed;
329 hostport = put_host_port(host, ssh_port);
331 if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
332 fatal("host_hash failed");
333 known_host = hash_hosts ? hashed : hostport;
335 fprintf(stdout, "%s ", known_host);
336 sshkey_write(key, stdout);
342 keyprint(con *c, struct sshkey *key)
344 char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
349 if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
350 keyprint_one(hosts, key);
353 ohosts = hosts = xstrdup(hosts);
354 while ((host = strsep(&hosts, ",")) != NULL)
355 keyprint_one(host, key);
360 tcpconnect(char *host)
362 struct addrinfo hints, *ai, *aitop;
363 char strport[NI_MAXSERV];
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));
374 for (ai = aitop; ai; ai = ai->ai_next) {
375 s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
377 error("socket: %s", strerror(errno));
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));
395 conalloc(char *iname, char *oname, int keytype)
397 char *namebase, *name, *namelist;
400 namebase = namelist = xstrdup(iname);
403 name = xstrsep(&namelist, ",");
408 } while ((s = tcpconnect(name)) < 0);
411 fatal("conalloc: fdno %d too high", s);
412 if (fdcon[s].c_status)
413 fatal("conalloc: attempt to reuse fdno %d", s);
415 debug3("%s: oname %s kt %d", __func__, oname, keytype);
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;
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);
437 if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
438 fatal("confree: attempt to free bad fdno %d", 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;
451 TAILQ_REMOVE(&tq, &fdcon[s], c_link);
452 FD_CLR(s, read_wait);
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);
471 ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
479 int n = 0, remote_major = 0, remote_minor = 0;
481 char remote_version[sizeof buf];
486 memset(buf, '\0', sizeof(buf));
487 bufsiz = sizeof(buf);
490 (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
495 if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
501 error("%s: Connection closed by remote host", c->c_name);
506 error("read (%s): %s", c->c_name, strerror(errno));
512 if (*cp != '\n' && *cp != '\r') {
513 error("%s: bad greeting", c->c_name);
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);
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);
533 } else if (remote_major != 1) {
534 debug("%s doesn't support ssh1", c->c_name);
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");
547 if (atomicio(vwrite, s, buf, n) != (size_t)n) {
548 error("write (%s): %s", c->c_name, strerror(errno));
552 if (c->c_keytype != KT_RSA1) {
557 c->c_status = CS_SIZE;
567 if (c->c_status == CS_CON) {
571 n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
573 error("read (%s): %s", c->c_name, strerror(errno));
579 if (c->c_off == c->c_len)
580 switch (c->c_status) {
582 c->c_plen = htonl(c->c_plen);
583 c->c_len = c->c_plen + 8 - (c->c_plen & 7);
585 c->c_data = xmalloc(c->c_len);
586 c->c_status = CS_KEYS;
590 keyprint(c, keygrab_ssh1(c));
595 fatal("conread: invalid status %d", c->c_status);
605 struct timeval seltime, now;
610 gettimeofday(&now, NULL);
611 c = TAILQ_FIRST(&tq);
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))) {
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;
623 timerclear(&seltime);
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));
630 while (select(maxfd, r, NULL, e, &seltime) == -1 &&
631 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
634 for (i = 0; i < maxfd; i++) {
635 if (FD_ISSET(i, e)) {
636 error("%s: exception!", fdcon[i].c_name);
638 } else if (FD_ISSET(i, r))
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))) {
649 c = TAILQ_NEXT(c, c_link);
657 char *name = strnnsep(&host, " \t\n");
662 for (j = KT_RSA1; j <= KT_ED25519; j *= 2) {
663 if (get_keytypes & j) {
664 while (ncon >= MAXCON)
666 conalloc(name, *host ? host : name, j);
672 fatal(const char *fmt,...)
677 do_log(SYSLOG_LEVEL_FATAL, fmt, args);
686 "usage: %s [-46cHv] [-f file] [-p port] [-T timeout] [-t type]\n"
687 "\t\t [host | addrlist namelist] ...\n",
693 main(int argc, char **argv)
695 int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
696 int opt, fopt_count = 0, j;
697 char *tname, *cp, line[NI_MAXHOST];
704 ssh_malloc_init(); /* must be called before any mallocs */
705 __progname = ssh_get_progname(argv[0]);
709 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
715 while ((opt = getopt(argc, argv, "cHv46p:T:t:f:")) != -1) {
724 ssh_port = a2port(optarg);
726 fprintf(stderr, "Bad port '%s'\n", optarg);
731 timeout = convtime(optarg);
732 if (timeout == -1 || timeout == 0) {
733 fprintf(stderr, "Bad timeout '%s'\n", optarg);
740 log_level = SYSLOG_LEVEL_DEBUG1;
742 else if (log_level < SYSLOG_LEVEL_DEBUG3)
745 fatal("Too high debugging level.");
748 if (strcmp(optarg, "-") == 0)
750 argv[fopt_count++] = optarg;
754 tname = strtok(optarg, ",");
756 int type = sshkey_type_from_name(tname);
761 get_keytypes |= KT_RSA1;
765 get_keytypes |= KT_DSA;
768 get_keytypes |= KT_ECDSA;
771 get_keytypes |= KT_RSA;
774 get_keytypes |= KT_ED25519;
778 fatal("Unknown key type \"%s\"", tname);
780 tname = strtok(NULL, ",");
794 if (optind == argc && !fopt_count)
797 log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
799 maxfd = fdlim_get(1);
801 fatal("%s: fdlim_get: bad value", __progname);
802 if (maxfd > MAXMAXFD)
805 fatal("%s: not enough file descriptors", __progname);
806 if (maxfd > fdlim_get(0))
808 fdcon = xcalloc(maxfd, sizeof(con));
810 read_wait_nfdset = howmany(maxfd, NFDBITS);
811 read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
813 for (j = 0; j < fopt_count; j++) {
816 else if ((fp = fopen(argv[j], "r")) == NULL)
817 fatal("%s: %s: %s", __progname, argv[j],
821 while (read_keyfile_line(fp,
822 argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
824 /* Chomp off trailing whitespace and comments */
825 if ((cp = strchr(line, '#')) == NULL)
826 cp = line + strlen(line) - 1;
828 if (*cp == ' ' || *cp == '\t' ||
829 *cp == '\n' || *cp == '#')
835 /* Skip empty lines */
843 fatal("%s: %s: %s", __progname, argv[j],
849 while (optind < argc)
850 do_host(argv[optind++]);