1 /* $OpenBSD: ssh-keyscan.c,v 1.119 2018/03/02 21:40:15 jmc 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 */
75 /* The number of seconds after which to give up on a TCP connection */
79 #define MAXCON (maxfd - 10)
81 extern char *__progname;
83 size_t read_wait_nfdset;
86 struct ssh *active_state = NULL; /* XXX needed for linking */
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] = kexdh_client;
266 c->c_ssh->kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
267 c->c_ssh->kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
268 c->c_ssh->kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
269 c->c_ssh->kex->kex[KEX_DH_GRP18_SHA512] = kexdh_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] = kexecdh_client;
276 c->c_ssh->kex->kex[KEX_C25519_SHA256] = kexc25519_client;
277 ssh_set_verify_host_key_callback(c->c_ssh, key_print_wrapper);
279 * do the key-exchange until an error occurs or until
280 * the key_print_wrapper() callback sets c_done.
282 ssh_dispatch_run(c->c_ssh, DISPATCH_BLOCK, &c->c_done);
286 keyprint_one(const char *host, struct sshkey *key)
289 const char *known_host, *hashed;
292 export_dns_rr(host, key, stdout, 0);
296 hostport = put_host_port(host, ssh_port);
298 if (hash_hosts && (hashed = host_hash(host, NULL, 0)) == NULL)
299 fatal("host_hash failed");
300 known_host = hash_hosts ? hashed : hostport;
302 fprintf(stdout, "%s ", known_host);
303 sshkey_write(key, stdout);
309 keyprint(con *c, struct sshkey *key)
311 char *hosts = c->c_output_name ? c->c_output_name : c->c_name;
316 if (get_cert || (!hash_hosts && ssh_port == SSH_DEFAULT_PORT)) {
317 keyprint_one(hosts, key);
320 ohosts = hosts = xstrdup(hosts);
321 while ((host = strsep(&hosts, ",")) != NULL)
322 keyprint_one(host, key);
327 tcpconnect(char *host)
329 struct addrinfo hints, *ai, *aitop;
330 char strport[NI_MAXSERV];
333 snprintf(strport, sizeof strport, "%d", ssh_port);
334 memset(&hints, 0, sizeof(hints));
335 hints.ai_family = IPv4or6;
336 hints.ai_socktype = SOCK_STREAM;
337 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) {
338 error("getaddrinfo %s: %s", host, ssh_gai_strerror(gaierr));
341 for (ai = aitop; ai; ai = ai->ai_next) {
342 s = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
344 error("socket: %s", strerror(errno));
347 if (set_nonblock(s) == -1)
348 fatal("%s: set_nonblock(%d)", __func__, s);
349 if (connect(s, ai->ai_addr, ai->ai_addrlen) < 0 &&
350 errno != EINPROGRESS)
351 error("connect (`%s'): %s", host, strerror(errno));
362 conalloc(char *iname, char *oname, int keytype)
364 char *namebase, *name, *namelist;
367 namebase = namelist = xstrdup(iname);
370 name = xstrsep(&namelist, ",");
375 } while ((s = tcpconnect(name)) < 0);
378 fatal("conalloc: fdno %d too high", s);
379 if (fdcon[s].c_status)
380 fatal("conalloc: attempt to reuse fdno %d", s);
382 debug3("%s: oname %s kt %d", __func__, oname, keytype);
384 fdcon[s].c_status = CS_CON;
385 fdcon[s].c_namebase = namebase;
386 fdcon[s].c_name = name;
387 fdcon[s].c_namelist = namelist;
388 fdcon[s].c_output_name = xstrdup(oname);
389 fdcon[s].c_data = (char *) &fdcon[s].c_plen;
392 fdcon[s].c_keytype = keytype;
393 monotime_tv(&fdcon[s].c_tv);
394 fdcon[s].c_tv.tv_sec += timeout;
395 TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
396 FD_SET(s, read_wait);
404 if (s >= maxfd || fdcon[s].c_status == CS_UNUSED)
405 fatal("confree: attempt to free bad fdno %d", s);
406 free(fdcon[s].c_namebase);
407 free(fdcon[s].c_output_name);
408 if (fdcon[s].c_status == CS_KEYS)
409 free(fdcon[s].c_data);
410 fdcon[s].c_status = CS_UNUSED;
411 fdcon[s].c_keytype = 0;
412 if (fdcon[s].c_ssh) {
413 ssh_packet_close(fdcon[s].c_ssh);
414 free(fdcon[s].c_ssh);
415 fdcon[s].c_ssh = NULL;
418 TAILQ_REMOVE(&tq, &fdcon[s], c_link);
419 FD_CLR(s, read_wait);
426 TAILQ_REMOVE(&tq, &fdcon[s], c_link);
427 monotime_tv(&fdcon[s].c_tv);
428 fdcon[s].c_tv.tv_sec += timeout;
429 TAILQ_INSERT_TAIL(&tq, &fdcon[s], c_link);
438 ret = conalloc(c->c_namelist, c->c_output_name, c->c_keytype);
446 int n = 0, remote_major = 0, remote_minor = 0;
448 char remote_version[sizeof buf];
452 /* send client banner */
453 n = snprintf(buf, sizeof buf, "SSH-%d.%d-OpenSSH-keyscan\r\n",
454 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2);
455 if (n < 0 || (size_t)n >= sizeof(buf)) {
456 error("snprintf: buffer too small");
460 if (atomicio(vwrite, s, buf, n) != (size_t)n) {
461 error("write (%s): %s", c->c_name, strerror(errno));
467 memset(buf, '\0', sizeof(buf));
468 bufsiz = sizeof(buf);
471 (n = atomicio(read, s, cp, 1)) == 1 && *cp != '\n') {
476 if (n != 1 || strncmp(buf, "SSH-", 4) == 0)
482 error("%s: Connection closed by remote host", c->c_name);
487 error("read (%s): %s", c->c_name, strerror(errno));
493 if (*cp != '\n' && *cp != '\r') {
494 error("%s: bad greeting", c->c_name);
499 if ((c->c_ssh = ssh_packet_set_connection(NULL, s, s)) == NULL)
500 fatal("ssh_packet_set_connection failed");
501 ssh_packet_set_timeout(c->c_ssh, timeout, 1);
502 ssh_set_app_data(c->c_ssh, c); /* back link */
503 if (sscanf(buf, "SSH-%d.%d-%[^\n]\n",
504 &remote_major, &remote_minor, remote_version) == 3)
505 c->c_ssh->compat = compat_datafellows(remote_version);
507 c->c_ssh->compat = 0;
508 if (!ssh2_capable(remote_major, remote_minor)) {
509 debug("%s doesn't support ssh2", c->c_name);
513 fprintf(stderr, "%c %s:%d %s\n", print_sshfp ? ';' : '#',
514 c->c_name, ssh_port, chop(buf));
525 if (c->c_status == CS_CON) {
529 n = atomicio(read, s, c->c_data + c->c_off, c->c_len - c->c_off);
531 error("read (%s): %s", c->c_name, strerror(errno));
537 if (c->c_off == c->c_len)
538 switch (c->c_status) {
540 c->c_plen = htonl(c->c_plen);
541 c->c_len = c->c_plen + 8 - (c->c_plen & 7);
543 c->c_data = xmalloc(c->c_len);
544 c->c_status = CS_KEYS;
547 fatal("conread: invalid status %d", c->c_status);
557 struct timeval seltime, now;
563 c = TAILQ_FIRST(&tq);
565 if (c && (c->c_tv.tv_sec > now.tv_sec ||
566 (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec > now.tv_usec))) {
568 seltime.tv_sec -= now.tv_sec;
569 seltime.tv_usec -= now.tv_usec;
570 if (seltime.tv_usec < 0) {
571 seltime.tv_usec += 1000000;
575 timerclear(&seltime);
577 r = xcalloc(read_wait_nfdset, sizeof(fd_mask));
578 e = xcalloc(read_wait_nfdset, sizeof(fd_mask));
579 memcpy(r, read_wait, read_wait_nfdset * sizeof(fd_mask));
580 memcpy(e, read_wait, read_wait_nfdset * sizeof(fd_mask));
582 while (select(maxfd, r, NULL, e, &seltime) == -1 &&
583 (errno == EAGAIN || errno == EINTR || errno == EWOULDBLOCK))
586 for (i = 0; i < maxfd; i++) {
587 if (FD_ISSET(i, e)) {
588 error("%s: exception!", fdcon[i].c_name);
590 } else if (FD_ISSET(i, r))
596 c = TAILQ_FIRST(&tq);
597 while (c && (c->c_tv.tv_sec < now.tv_sec ||
598 (c->c_tv.tv_sec == now.tv_sec && c->c_tv.tv_usec < now.tv_usec))) {
601 c = TAILQ_NEXT(c, c_link);
609 char *name = strnnsep(&host, " \t\n");
614 for (j = KT_MIN; j <= KT_MAX; j *= 2) {
615 if (get_keytypes & j) {
616 while (ncon >= MAXCON)
618 conalloc(name, *host ? host : name, j);
624 fatal(const char *fmt,...)
629 do_log(SYSLOG_LEVEL_FATAL, fmt, args);
638 "usage: %s [-46cDHv] [-f file] [-p port] [-T timeout] [-t type]\n"
639 "\t\t [host | addrlist namelist]\n",
645 main(int argc, char **argv)
647 int debug_flag = 0, log_level = SYSLOG_LEVEL_INFO;
648 int opt, fopt_count = 0, j;
649 char *tname, *cp, line[NI_MAXHOST];
656 ssh_malloc_init(); /* must be called before any mallocs */
657 __progname = ssh_get_progname(argv[0]);
661 /* Ensure that fds 0, 1 and 2 are open or directed to /dev/null */
667 while ((opt = getopt(argc, argv, "cDHv46p:T:t:f:")) != -1) {
679 ssh_port = a2port(optarg);
681 fprintf(stderr, "Bad port '%s'\n", optarg);
686 timeout = convtime(optarg);
687 if (timeout == -1 || timeout == 0) {
688 fprintf(stderr, "Bad timeout '%s'\n", optarg);
695 log_level = SYSLOG_LEVEL_DEBUG1;
697 else if (log_level < SYSLOG_LEVEL_DEBUG3)
700 fatal("Too high debugging level.");
703 if (strcmp(optarg, "-") == 0)
705 argv[fopt_count++] = optarg;
709 tname = strtok(optarg, ",");
711 int type = sshkey_type_from_name(tname);
715 get_keytypes |= KT_DSA;
718 get_keytypes |= KT_ECDSA;
721 get_keytypes |= KT_RSA;
724 get_keytypes |= KT_ED25519;
727 get_keytypes |= KT_XMSS;
731 fatal("Unknown key type \"%s\"", tname);
733 tname = strtok(NULL, ",");
747 if (optind == argc && !fopt_count)
750 log_init("ssh-keyscan", log_level, SYSLOG_FACILITY_USER, 1);
752 maxfd = fdlim_get(1);
754 fatal("%s: fdlim_get: bad value", __progname);
755 if (maxfd > MAXMAXFD)
758 fatal("%s: not enough file descriptors", __progname);
759 if (maxfd > fdlim_get(0))
761 fdcon = xcalloc(maxfd, sizeof(con));
763 read_wait_nfdset = howmany(maxfd, NFDBITS);
764 read_wait = xcalloc(read_wait_nfdset, sizeof(fd_mask));
766 for (j = 0; j < fopt_count; j++) {
769 else if ((fp = fopen(argv[j], "r")) == NULL)
770 fatal("%s: %s: %s", __progname, argv[j],
774 while (read_keyfile_line(fp,
775 argv[j] == NULL ? "(stdin)" : argv[j], line, sizeof(line),
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],
802 while (optind < argc)
803 do_host(argv[optind++]);