1 /* $OpenBSD: ssh-keyscan.c,v 1.126 2019/01/26 22:35:01 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>
40 #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;
59 #define KT_ECDSA (1<<2)
60 #define KT_ED25519 (1<<3)
61 #define KT_XMSS (1<<4)
64 #define KT_MAX KT_XMSS
67 int get_keytypes = KT_RSA|KT_ECDSA|KT_ED25519;
69 int hash_hosts = 0; /* Hash hostname on output */
71 int print_sshfp = 0; /* Print SSHFP records instead of known_hosts */
73 int found_one = 0; /* Successfully found a key */
77 /* The number of seconds after which to give up on a TCP connection */
81 #define MAXCON (maxfd - 10)
83 extern char *__progname;
85 size_t read_wait_nfdset;
89 * Keep a connection structure for each file descriptor. The state
90 * associated with file descriptor n is held in fdcon[n].
92 typedef struct Connection {
93 u_char c_status; /* State of connection on this file desc. */
94 #define CS_UNUSED 0 /* File descriptor unused */
95 #define CS_CON 1 /* Waiting to connect/read greeting */
96 #define CS_SIZE 2 /* Waiting to read initial packet size */
97 #define CS_KEYS 3 /* Waiting to read public key packet */
98 int c_fd; /* Quick lookup: c->c_fd == c - fdcon */
99 int c_plen; /* Packet length field for ssh packet */
100 int c_len; /* Total bytes which must be read. */
101 int c_off; /* Length of data read so far. */
102 int c_keytype; /* Only one of KT_* */
103 sig_atomic_t c_done; /* SSH2 done */
104 char *c_namebase; /* Address to free for c_name and c_namelist */
105 char *c_name; /* Hostname of connection for errors */
106 char *c_namelist; /* Pointer to other possible addresses */
107 char *c_output_name; /* Hostname of connection for output */
108 char *c_data; /* Data read from this fd */
109 struct ssh *c_ssh; /* SSH-connection */
110 struct timeval c_tv; /* Time at which connection gets aborted */
111 TAILQ_ENTRY(Connection) c_link; /* List of connections in timeout order. */
114 TAILQ_HEAD(conlist, Connection) tq; /* Timeout Queue */
117 static void keyprint(con *c, struct sshkey *key);
122 #if defined(HAVE_GETRLIMIT) && defined(RLIMIT_NOFILE)
125 if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
127 if ((hard ? rlfd.rlim_max : rlfd.rlim_cur) == RLIM_INFINITY)
130 return hard ? rlfd.rlim_max : rlfd.rlim_cur;
139 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
145 #if defined(HAVE_SETRLIMIT) && defined(RLIMIT_NOFILE)
146 if (getrlimit(RLIMIT_NOFILE, &rlfd) < 0)
149 if (setrlimit(RLIMIT_NOFILE, &rlfd) < 0)
151 #elif defined (HAVE_SETDTABLESIZE)
158 * This is an strsep function that returns a null field for adjacent
159 * separators. This is the same as the 4.4BSD strsep, but different from the
160 * one in the GNU libc.
163 xstrsep(char **str, const char *delim)
171 e = s + strcspn(s, delim);
181 * Get the next non-null token (like GNU strsep). Strsep() will return a
182 * null token for two adjacent separators, so we may have to loop.
185 strnnsep(char **stringp, char *delim)
190 tok = xstrsep(stringp, delim);
191 } while (tok && *tok == '\0');
197 key_print_wrapper(struct sshkey *hostkey, struct ssh *ssh)
201 if ((c = ssh_get_app_data(ssh)) != NULL)
202 keyprint(c, hostkey);
203 /* always abort key exchange */
208 ssh2_capable(int remote_major, int remote_minor)
210 switch (remote_major) {
212 if (remote_minor == 99)
226 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
229 switch (c->c_keytype) {
231 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
232 "ssh-dss-cert-v01@openssh.com" : "ssh-dss";
235 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
236 "ssh-rsa-cert-v01@openssh.com" : "ssh-rsa";
239 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
240 "ssh-ed25519-cert-v01@openssh.com" : "ssh-ed25519";
243 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
244 "ssh-xmss-cert-v01@openssh.com" : "ssh-xmss@openssh.com";
247 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = get_cert ?
248 "ecdsa-sha2-nistp256-cert-v01@openssh.com,"
249 "ecdsa-sha2-nistp384-cert-v01@openssh.com,"
250 "ecdsa-sha2-nistp521-cert-v01@openssh.com" :
251 "ecdsa-sha2-nistp256,"
252 "ecdsa-sha2-nistp384,"
253 "ecdsa-sha2-nistp521";
256 fatal("unknown key type %d", c->c_keytype);
259 if ((r = kex_setup(c->c_ssh, myproposal)) != 0) {
261 fprintf(stderr, "kex_setup: %s\n", ssh_err(r));
265 c->c_ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client;
266 c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client;
267 c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client;
268 c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client;
269 c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client;
270 c->c_ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
271 c->c_ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
272 # ifdef OPENSSL_HAS_ECC
273 c->c_ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client;
276 c->c_ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client;
277 c->c_ssh->kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_client;
278 ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
280 * do the key-exchange until an error occurs or until
281 * the key_print_wrapper() callback sets c_done.
283 ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
287 keyprint_one(const char *host, struct sshkey *key)
290 const char *known_host, *hashed;
295 export_dns_rr(host, key, stdout, 0);
299 hostport = put_host_port(host, ssh_port);
301 if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
302 fatal("host_hash failed");
303 known_host = hash_hosts ? hashed : hostport;
305 fprintf(stdout, "%s ", known_host);
306 sshkey_write(key, stdout);
312 keyprint(con *c, struct sshkey *key)
314 char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
319 if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
320 keyprint_one(hosts, key);
323 ohosts = hosts = xstrdup(hosts);
324 while ((host = strsep(&hosts, ",")) != NULL)
325 keyprint_one(host, key);
330 tcpconnect(char *host)
332 struct addrinfo hints, *ai, *aitop;
333 char strport[NI_MAXSERV];
336 snprintf(strport, sizeof strport, "%d", ssh_port);
337 memset(&hints, 0, sizeof(hints));
338 hints.ai_family = IPv4or6;
339 hints.ai_socktype = SOCK_STREAM;
340 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
341 error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
344 for (ai = aitop; ai; ai = ai->ai_next) {
345 s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
347 error("socket: %s", strerror(errno));
350 if (set_nonblock(s) == -1)
351 fatal("%s: set_nonblock(%d)", __func__, s);
352 if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
353 errno != EINPROGRESS)
354 error("connect (`%s'): %s", host, strerror(errno));
365 conalloc(char *iname, char *oname, int keytype)
367 char *namebase, *name, *namelist;
370 namebase = namelist = xstrdup(iname);
373 name = xstrsep(&namelist, ",");
378 } while ((s = tcpconnect(name)) < 0);
381 fatal("conalloc: fdno %d too high", s);
382 if (fdcon[s].c_status)
383 fatal("conalloc: attempt to reuse fdno %d", s);
385 debug3("%s: oname %s kt %d", __func__, oname, keytype);
387 fdcon[s].c_status = CS_CON;
388 fdcon[s].c_namebase = namebase;
389 fdcon[s].c_name = name;
390 fdcon[s].c_namelist = namelist;
391 fdcon[s].c_output_name = xstrdup(oname);
392 fdcon[s].c_data = (char *) &fdcon[s].c_plen;
395 fdcon[s].c_keytype = keytype;
396 monotime_tv(&fdcon[s].c_tv);
397 fdcon[s].c_tv.tv_sec += timeout;
398 TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
399 FD_SET(s, read_wait);
407 if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
408 fatal("confree: attempt to free bad fdno %d", s);
409 free(fdcon[s].c_namebase);
410 free(fdcon[s].c_output_name);
411 if (fdcon[s].c_status == CS_KEYS)
412 free(fdcon[s].c_data);
413 fdcon[s].c_status = CS_UNUSED;
414 fdcon[s].c_keytype = 0;
415 if (fdcon[s].c_ssh) {
416 ssh_packet_close(fdcon[s].c_ssh);
417 free(fdcon[s].c_ssh);
418 fdcon[s].c_ssh = NULL;
421 TAILQ_REMOVE(&tq, &fdcon[s], c_link);
422 FD_CLR(s, read_wait);
429 TAILQ_REMOVE(&tq, &fdcon[s], c_link);
430 monotime_tv(&fdcon[s].c_tv);
431 fdcon[s].c_tv.tv_sec += timeout;
432 TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
441 ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
449 int n = 0, remote_major = 0, remote_minor = 0;
451 char remote_version[sizeof buf];
455 /* send client banner */
456 n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
457 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
458 if (n < 0 || (size_t)n >= sizeof(buf)) {
459 error("snprintf: buffer too small");
463 if (atomicio(vwrite, s, buf, n) != (size_t)n) {
464 error("write (%s): %s", c->c_name, strerror(errno));
470 memset(buf, '\0', sizeof(buf));
471 bufsiz = sizeof(buf);
474 (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
479 if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
485 error("%s: Connection closed by remote host", c->c_name);
490 error("read (%s): %s", c->c_name, strerror(errno));
496 if (*cp != '\n' && *cp != '\r') {
497 error("%s: bad greeting", c->c_name);
502 if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
503 fatal("ssh_packet_set_connection failed");
504 ssh_packet_set_timeout(c->c_ssh, timeout, 1);
505 ssh_set_app_data(c->c_ssh, c); /* back link */
506 if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
507 &remote_major, &remote_minor, remote_version) == 3)
508 c->c_ssh->compat = compat_datafellows(remote_version);
510 c->c_ssh->compat = 0;
511 if (!ssh2_capable(remote_major, remote_minor)) {
512 debug("%s doesn't support ssh2", c->c_name);
516 fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
517 c->c_name, ssh_port, chop(buf));
528 if (c->c_status == CS_CON) {
532 n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
534 error("read (%s): %s", c->c_name, strerror(errno));
540 if (c->c_off == c->c_len)
541 switch (c->c_status) {
543 c->c_plen = htonl(c->c_plen);
544 c->c_len = c->c_plen + 8 - (c->c_plen & 7);
546 c->c_data = xmalloc(c->c_len);
547 c->c_status = CS_KEYS;
550 fatal("conread: invalid status %d", c->c_status);
560 struct timeval seltime, now;
566 c = TAILQ_FIRST(&tq);
568 if (c && (c->c_tv.tv_sec > now.tv_sec ||
569 (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
571 seltime.tv_sec -= now.tv_sec;
572 seltime.tv_usec -= now.tv_usec;
573 if (seltime.tv_usec < 0) {
574 seltime.tv_usec += 1000000;
578 timerclear(&seltime);
580 r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
581 e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
582 memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
583 memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
585 while (select(maxfd, r, NULL, e, &seltime) == -1 &&
586 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
589 for (i = 0; i < maxfd; i++) {
590 if (FD_ISSET(i, e)) {
591 error("%s: exception!", fdcon[i].c_name);
593 } else if (FD_ISSET(i, r))
599 c = TAILQ_FIRST(&tq);
600 while (c && (c->c_tv.tv_sec < now.tv_sec ||
601 (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
604 c = TAILQ_NEXT(c, c_link);
612 char *name = strnnsep(&host, " \t\n");
617 for (j = KT_MIN; j <= KT_MAX; j *= 2) {
618 if (get_keytypes & j) {
619 while (ncon >= MAXCON)
621 conalloc(name, *host ? host : name, j);
627 fatal(const char *fmt,...)
632 do_log(SYSLOG_LEVEL_FATAL, fmt, args);
641 "usage: %s [-46cDHv] [-f file] [-p port] [-T timeout] [-t type]\n"
642 "\t\t [host | addrlist namelist]\n",
648 main(int argc, char **argv)
650 int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
651 int opt, fopt_count = 0, j;
652 char *tname, *cp, *line = NULL;
659 ssh_malloc_init(); /* must be called before any mallocs */
660 __progname = ssh_get_progname(argv[0]);
664 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
670 while ((opt = getopt(argc, argv, "cDHv46p:T:t:f:")) != -1) {
682 ssh_port = a2port(optarg);
684 fprintf(stderr, "Bad port '%s'\n", optarg);
689 timeout = convtime(optarg);
690 if (timeout == -1 || timeout == 0) {
691 fprintf(stderr, "Bad timeout '%s'\n", optarg);
698 log_level = SYSLOG_LEVEL_DEBUG1;
700 else if (log_level < SYSLOG_LEVEL_DEBUG3)
703 fatal("Too high debugging level.");
706 if (strcmp(optarg, "-") == 0)
708 argv[fopt_count++] = optarg;
712 tname = strtok(optarg, ",");
714 int type = sshkey_type_from_name(tname);
718 get_keytypes |= KT_DSA;
721 get_keytypes |= KT_ECDSA;
724 get_keytypes |= KT_RSA;
727 get_keytypes |= KT_ED25519;
730 get_keytypes |= KT_XMSS;
734 fatal("Unknown key type \"%s\"", tname);
736 tname = strtok(NULL, ",");
750 if (optind == argc && !fopt_count)
753 log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
755 maxfd = fdlim_get(1);
757 fatal("%s: fdlim_get: bad value", __progname);
758 if (maxfd > MAXMAXFD)
761 fatal("%s: not enough file descriptors", __progname);
762 if (maxfd > fdlim_get(0))
764 fdcon = xcalloc(maxfd, sizeof(con));
766 read_wait_nfdset = howmany(maxfd, NFDBITS);
767 read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
769 for (j = 0; j < fopt_count; j++) {
772 else if ((fp = fopen(argv[j], "r")) == NULL)
773 fatal("%s: %s: %s", __progname, argv[j],
776 while (getline(&line, &linesize, fp) != -1) {
777 /* Chomp off trailing whitespace and comments */
778 if ((cp = strchr(line, '#')) == NULL)
779 cp = line + strlen(line) - 1;
781 if (*cp == ' ' || *cp == '\t' ||
782 *cp == '\n' || *cp == '#')
788 /* Skip empty lines */
796 fatal("%s: %s: %s", __progname, argv[j],
803 while (optind < argc)
804 do_host(argv[optind++]);
809 return found_one ? 0 : 1;