2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * Code to connect to a remote host, and to perform the client side of the
6 * login (authentication) dialog.
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
16 RCSID("$OpenBSD: sshconnect.c,v 1.172 2006/02/08 12:15:27 stevesk Exp $");
20 #include <openssl/bn.h>
30 #include "sshconnect.h"
38 char *client_version_string = NULL;
39 char *server_version_string = NULL;
41 static int matching_host_key_dns = 0;
44 extern Options options;
45 extern char *__progname;
46 extern uid_t original_real_uid;
47 extern uid_t original_effective_uid;
48 extern pid_t proxy_command_pid;
50 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
51 #define INET6_ADDRSTRLEN 46
54 static int show_other_keys(const char *, Key *);
55 static void warn_changed_key(Key *);
58 * Connect to the given ssh server using a proxy command.
61 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
63 char *command_string, *tmp;
66 char strport[NI_MAXSERV];
69 /* Convert the port number into a string. */
70 snprintf(strport, sizeof strport, "%hu", port);
73 * Build the final command string in the buffer by making the
74 * appropriate substitutions to the given proxy command.
76 * Use "exec" to avoid "sh -c" processes on some platforms
79 len = strlen(proxy_command) + 6;
81 strlcpy(tmp, "exec ", len);
82 strlcat(tmp, proxy_command, len);
83 command_string = percent_expand(tmp, "h", host,
84 "p", strport, (char *)NULL);
87 /* Create pipes for communicating with the proxy. */
88 if (pipe(pin) < 0 || pipe(pout) < 0)
89 fatal("Could not create pipes to communicate with the proxy: %.100s",
92 debug("Executing proxy command: %.500s", command_string);
94 /* Fork and execute the proxy command. */
95 if ((pid = fork()) == 0) {
98 /* Child. Permanently give up superuser privileges. */
99 seteuid(original_real_uid);
100 setuid(original_real_uid);
102 /* Redirect stdin and stdout. */
105 if (dup2(pin[0], 0) < 0)
106 perror("dup2 stdin");
110 if (dup2(pout[1], 1) < 0)
111 perror("dup2 stdout");
112 /* Cannot be 1 because pin allocated two descriptors. */
115 /* Stderr is left as it is so that error messages get
116 printed on the user's terminal. */
117 argv[0] = _PATH_BSHELL;
119 argv[2] = command_string;
122 /* Execute the proxy command. Note that we gave up any
123 extra privileges above. */
124 execv(argv[0], argv);
130 fatal("fork failed: %.100s", strerror(errno));
132 proxy_command_pid = pid; /* save pid to clean up later */
134 /* Close child side of the descriptors. */
138 /* Free the command name. */
139 xfree(command_string);
141 /* Set the connection file descriptors. */
142 packet_set_connection(pout[0], pin[1]);
144 /* Indicate OK return */
149 * Creates a (possibly privileged) socket for use as the ssh connection.
152 ssh_create_socket(int privileged, struct addrinfo *ai)
155 struct addrinfo hints, *res;
158 * If we are running as root and want to connect to a privileged
159 * port, bind our own socket to a privileged port.
162 int p = IPPORT_RESERVED - 1;
164 sock = rresvport_af(&p, ai->ai_family);
167 error("rresvport: af=%d %.100s", ai->ai_family,
170 debug("Allocated local port %d.", p);
173 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
175 error("socket: %.100s", strerror(errno));
177 /* Bind the socket to an alternative local IP address */
178 if (options.bind_address == NULL)
181 memset(&hints, 0, sizeof(hints));
182 hints.ai_family = ai->ai_family;
183 hints.ai_socktype = ai->ai_socktype;
184 hints.ai_protocol = ai->ai_protocol;
185 hints.ai_flags = AI_PASSIVE;
186 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
188 error("getaddrinfo: %s: %s", options.bind_address,
189 gai_strerror(gaierr));
193 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
194 error("bind: %s: %s", options.bind_address, strerror(errno));
204 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
205 socklen_t addrlen, int timeout)
210 int fdsetsz, optval, rc, result = -1;
213 return (connect(sockfd, serv_addr, addrlen));
215 set_nonblock(sockfd);
216 rc = connect(sockfd, serv_addr, addrlen);
218 unset_nonblock(sockfd);
221 if (errno != EINPROGRESS)
224 fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
225 fdset = (fd_set *)xmalloc(fdsetsz);
227 memset(fdset, 0, fdsetsz);
228 FD_SET(sockfd, fdset);
233 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
234 if (rc != -1 || errno != EINTR)
245 debug("select: %s", strerror(errno));
248 /* Completed or failed */
250 optlen = sizeof(optval);
251 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
253 debug("getsockopt: %s", strerror(errno));
261 unset_nonblock(sockfd);
264 /* Should not occur */
265 fatal("Bogus return (%d) from select()", rc);
273 * Opens a TCP/IP connection to the remote server on the given host.
274 * The address of the remote host will be returned in hostaddr.
275 * If port is 0, the default port will be used. If needpriv is true,
276 * a privileged port will be allocated to make the connection.
277 * This requires super-user privileges if needpriv is true.
278 * Connection_attempts specifies the maximum number of tries (one per
279 * second). If proxy_command is non-NULL, it specifies the command (with %h
280 * and %p substituted for host and port, respectively) to use to contact
284 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
285 u_short port, int family, int connection_attempts,
286 int needpriv, const char *proxy_command)
290 int sock = -1, attempt;
291 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
292 struct addrinfo hints, *ai, *aitop;
294 debug2("ssh_connect: needpriv %d", needpriv);
296 /* If a proxy command is given, connect using it. */
297 if (proxy_command != NULL)
298 return ssh_proxy_connect(host, port, proxy_command);
300 /* No proxy command. */
302 memset(&hints, 0, sizeof(hints));
303 hints.ai_family = family;
304 hints.ai_socktype = SOCK_STREAM;
305 snprintf(strport, sizeof strport, "%u", port);
306 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
307 fatal("%s: %.100s: %s", __progname, host,
308 gai_strerror(gaierr));
311 * Try to connect several times. On some machines, the first time
312 * will sometimes fail. In general socket code appears to behave
313 * quite magically on many machines.
315 for (attempt = 0; ;) {
317 debug("Trying again...");
319 /* Loop through addresses for this host, and try each one in
320 sequence until the connection succeeds. */
321 for (ai = aitop; ai; ai = ai->ai_next) {
322 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
324 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
325 ntop, sizeof(ntop), strport, sizeof(strport),
326 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
327 error("ssh_connect: getnameinfo failed");
330 debug("Connecting to %.200s [%.100s] port %s.",
331 host, ntop, strport);
333 /* Create a socket for connecting. */
334 sock = ssh_create_socket(needpriv, ai);
336 /* Any error is already output */
339 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
340 options.connection_timeout) >= 0) {
341 /* Successful connection. */
342 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
345 debug("connect to address %s port %s: %s",
346 ntop, strport, strerror(errno));
348 * Close the failed socket; there appear to
349 * be some problems when reusing a socket for
350 * which connect() has already returned an
357 break; /* Successful connection. */
360 if (attempt >= connection_attempts)
362 /* Sleep a moment before retrying. */
368 /* Return failure if we didn't get a successful connection. */
369 if (attempt >= connection_attempts) {
370 error("ssh: connect to host %s port %s: %s",
371 host, strport, strerror(errno));
375 debug("Connection established.");
377 /* Set SO_KEEPALIVE if requested. */
378 if (options.tcp_keep_alive &&
379 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
381 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
383 /* Set the connection. */
384 packet_set_connection(sock, sock);
390 * Waits for the server identification string, and sends our own
391 * identification string.
394 ssh_exchange_identification(void)
396 char buf[256], remote_version[256]; /* must be same size! */
397 int remote_major, remote_minor, mismatch;
398 int connection_in = packet_get_connection_in();
399 int connection_out = packet_get_connection_out();
400 int minor1 = PROTOCOL_MINOR_1;
403 /* Read other side's version identification. */
405 for (i = 0; i < sizeof(buf) - 1; i++) {
406 size_t len = atomicio(read, connection_in, &buf[i], 1);
408 if (len != 1 && errno == EPIPE)
409 fatal("ssh_exchange_identification: Connection closed by remote host");
411 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
412 if (buf[i] == '\r') {
415 continue; /**XXX wait for \n */
417 if (buf[i] == '\n') {
422 buf[sizeof(buf) - 1] = 0;
423 if (strncmp(buf, "SSH-", 4) == 0)
425 debug("ssh_exchange_identification: %s", buf);
427 server_version_string = xstrdup(buf);
430 * Check that the versions match. In future this might accept
431 * several versions and set appropriate flags to handle them.
433 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
434 &remote_major, &remote_minor, remote_version) != 3)
435 fatal("Bad remote protocol version identification: '%.100s'", buf);
436 debug("Remote protocol version %d.%d, remote software version %.100s",
437 remote_major, remote_minor, remote_version);
439 compat_datafellows(remote_version);
442 switch (remote_major) {
444 if (remote_minor == 99 &&
445 (options.protocol & SSH_PROTO_2) &&
446 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
450 if (!(options.protocol & SSH_PROTO_1)) {
454 if (remote_minor < 3) {
455 fatal("Remote machine has too old SSH software version.");
456 } else if (remote_minor == 3 || remote_minor == 4) {
457 /* We speak 1.3, too. */
460 if (options.forward_agent) {
461 logit("Agent forwarding disabled for protocol 1.3");
462 options.forward_agent = 0;
467 if (options.protocol & SSH_PROTO_2) {
477 fatal("Protocol major versions differ: %d vs. %d",
478 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
480 /* Send our own protocol version identification. */
481 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
482 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
483 compat20 ? PROTOCOL_MINOR_2 : minor1,
485 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
486 fatal("write: %.100s", strerror(errno));
487 client_version_string = xstrdup(buf);
488 chop(client_version_string);
489 chop(server_version_string);
490 debug("Local version string %.100s", client_version_string);
493 /* defaults to 'no' */
495 confirm(const char *prompt)
497 const char *msg, *again = "Please type 'yes' or 'no': ";
501 if (options.batch_mode)
503 for (msg = prompt;;msg = again) {
504 p = read_passphrase(msg, RP_ECHO);
506 (p[0] == '\0') || (p[0] == '\n') ||
507 strncasecmp(p, "no", 2) == 0)
509 if (p && strncasecmp(p, "yes", 3) == 0)
519 * check whether the supplied host key is valid, return -1 if the key
520 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
523 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
524 int readonly, const char *user_hostfile, const char *system_hostfile)
527 const char *type = key_type(host_key);
529 char hostline[1000], *hostp, *fp;
530 HostStatus host_status;
531 HostStatus ip_status;
532 int r, local = 0, host_ip_differ = 0;
534 char ntop[NI_MAXHOST];
536 int len, host_line, ip_line;
537 const char *host_file = NULL, *ip_file = NULL;
540 * Force accepting of the host key for loopback/localhost. The
541 * problem is that if the home directory is NFS-mounted to multiple
542 * machines, localhost will refer to a different machine in each of
543 * them, and the user will get bogus HOST_CHANGED warnings. This
544 * essentially disables host authentication for localhost; however,
545 * this is probably not a real problem.
547 /** hostaddr == 0! */
548 switch (hostaddr->sa_family) {
550 local = (ntohl(((struct sockaddr_in *)hostaddr)->
551 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
552 salen = sizeof(struct sockaddr_in);
555 local = IN6_IS_ADDR_LOOPBACK(
556 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
557 salen = sizeof(struct sockaddr_in6);
561 salen = sizeof(struct sockaddr_storage);
564 if (options.no_host_authentication_for_localhost == 1 && local &&
565 options.host_key_alias == NULL) {
566 debug("Forcing accepting of host key for "
567 "loopback/localhost.");
572 * We don't have the remote ip-address for connections
573 * using a proxy command
575 if (options.proxy_command == NULL) {
576 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
577 NULL, 0, NI_NUMERICHOST) != 0)
578 fatal("check_host_key: getnameinfo failed");
581 ip = xstrdup("<no hostip for proxy command>");
584 * Turn off check_host_ip if the connection is to localhost, via proxy
585 * command or if we don't have a hostname to compare with
587 if (options.check_host_ip &&
588 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
589 options.check_host_ip = 0;
592 * Allow the user to record the key under a different name. This is
593 * useful for ssh tunneling over forwarded connections or if you run
594 * multiple sshd's on different ports on the same machine.
596 if (options.host_key_alias != NULL) {
597 host = options.host_key_alias;
598 debug("using hostkeyalias: %s", host);
602 * Store the host key from the known host file in here so that we can
603 * compare it with the key for the IP address.
605 file_key = key_new(host_key->type);
608 * Check if the host key is present in the user's list of known
609 * hosts or in the systemwide list.
611 host_file = user_hostfile;
612 host_status = check_host_in_hostfile(host_file, host, host_key,
613 file_key, &host_line);
614 if (host_status == HOST_NEW) {
615 host_file = system_hostfile;
616 host_status = check_host_in_hostfile(host_file, host, host_key,
617 file_key, &host_line);
620 * Also perform check for the ip address, skip the check if we are
621 * localhost or the hostname was an ip address to begin with
623 if (options.check_host_ip) {
624 Key *ip_key = key_new(host_key->type);
626 ip_file = user_hostfile;
627 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
629 if (ip_status == HOST_NEW) {
630 ip_file = system_hostfile;
631 ip_status = check_host_in_hostfile(ip_file, ip,
632 host_key, ip_key, &ip_line);
634 if (host_status == HOST_CHANGED &&
635 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
640 ip_status = host_status;
644 switch (host_status) {
646 /* The host is known and the key matches. */
647 debug("Host '%.200s' is known and matches the %s host key.",
649 debug("Found key in %s:%d", host_file, host_line);
650 if (options.check_host_ip && ip_status == HOST_NEW) {
652 logit("%s host key for IP address "
653 "'%.128s' not in list of known hosts.",
655 else if (!add_host_to_hostfile(user_hostfile, ip,
656 host_key, options.hash_known_hosts))
657 logit("Failed to add the %s host key for IP "
658 "address '%.128s' to the list of known "
659 "hosts (%.30s).", type, ip, user_hostfile);
661 logit("Warning: Permanently added the %s host "
662 "key for IP address '%.128s' to the list "
663 "of known hosts.", type, ip);
669 /* The host is new. */
670 if (options.strict_host_key_checking == 1) {
672 * User has requested strict host key checking. We
673 * will not add the host key automatically. The only
674 * alternative left is to abort.
676 error("No %s host key is known for %.200s and you "
677 "have requested strict checking.", type, host);
679 } else if (options.strict_host_key_checking == 2) {
680 char msg1[1024], msg2[1024];
682 if (show_other_keys(host, host_key))
683 snprintf(msg1, sizeof(msg1),
684 "\nbut keys of different type are already"
685 " known for this host.");
687 snprintf(msg1, sizeof(msg1), ".");
689 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
691 if (options.verify_host_key_dns) {
692 if (matching_host_key_dns)
693 snprintf(msg2, sizeof(msg2),
694 "Matching host key fingerprint"
697 snprintf(msg2, sizeof(msg2),
698 "No matching host key fingerprint"
701 snprintf(msg, sizeof(msg),
702 "The authenticity of host '%.200s (%s)' can't be "
704 "%s key fingerprint is %s.\n%s"
705 "Are you sure you want to continue connecting "
707 host, ip, msg1, type, fp, msg2);
713 * If not in strict mode, add the key automatically to the
714 * local known_hosts file.
716 if (options.check_host_ip && ip_status == HOST_NEW) {
717 snprintf(hostline, sizeof(hostline), "%s,%s",
720 if (options.hash_known_hosts) {
721 /* Add hash of host and IP separately */
722 r = add_host_to_hostfile(user_hostfile, host,
723 host_key, options.hash_known_hosts) &&
724 add_host_to_hostfile(user_hostfile, ip,
725 host_key, options.hash_known_hosts);
727 /* Add unhashed "host,ip" */
728 r = add_host_to_hostfile(user_hostfile,
730 options.hash_known_hosts);
733 r = add_host_to_hostfile(user_hostfile, host, host_key,
734 options.hash_known_hosts);
739 logit("Failed to add the host to the list of known "
740 "hosts (%.500s).", user_hostfile);
742 logit("Warning: Permanently added '%.200s' (%s) to the "
743 "list of known hosts.", hostp, type);
746 if (options.check_host_ip && host_ip_differ) {
748 if (ip_status == HOST_NEW)
749 key_msg = "is unknown";
750 else if (ip_status == HOST_OK)
751 key_msg = "is unchanged";
753 key_msg = "has a different value";
754 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
755 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
756 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
757 error("The %s host key for %s has changed,", type, host);
758 error("and the key for the according IP address %s", ip);
759 error("%s. This could either mean that", key_msg);
760 error("DNS SPOOFING is happening or the IP address for the host");
761 error("and its host key have changed at the same time.");
762 if (ip_status != HOST_NEW)
763 error("Offending key for IP in %s:%d", ip_file, ip_line);
765 /* The host key has changed. */
766 warn_changed_key(host_key);
767 error("Add correct host key in %.100s to get rid of this message.",
769 error("Offending key in %s:%d", host_file, host_line);
772 * If strict host key checking is in use, the user will have
773 * to edit the key manually and we can only abort.
775 if (options.strict_host_key_checking) {
776 error("%s host key for %.200s has changed and you have "
777 "requested strict checking.", type, host);
782 * If strict host key checking has not been requested, allow
783 * the connection but without MITM-able authentication or
786 if (options.password_authentication) {
787 error("Password authentication is disabled to avoid "
788 "man-in-the-middle attacks.");
789 options.password_authentication = 0;
791 if (options.kbd_interactive_authentication) {
792 error("Keyboard-interactive authentication is disabled"
793 " to avoid man-in-the-middle attacks.");
794 options.kbd_interactive_authentication = 0;
795 options.challenge_response_authentication = 0;
797 if (options.challenge_response_authentication) {
798 error("Challenge/response authentication is disabled"
799 " to avoid man-in-the-middle attacks.");
800 options.challenge_response_authentication = 0;
802 if (options.forward_agent) {
803 error("Agent forwarding is disabled to avoid "
804 "man-in-the-middle attacks.");
805 options.forward_agent = 0;
807 if (options.forward_x11) {
808 error("X11 forwarding is disabled to avoid "
809 "man-in-the-middle attacks.");
810 options.forward_x11 = 0;
812 if (options.num_local_forwards > 0 ||
813 options.num_remote_forwards > 0) {
814 error("Port forwarding is disabled to avoid "
815 "man-in-the-middle attacks.");
816 options.num_local_forwards =
817 options.num_remote_forwards = 0;
820 * XXX Should permit the user to change to use the new id.
821 * This could be done by converting the host key to an
822 * identifying sentence, tell that the host identifies itself
823 * by that sentence, and ask the user if he/she whishes to
824 * accept the authentication.
828 fatal("internal error");
832 if (options.check_host_ip && host_status != HOST_CHANGED &&
833 ip_status == HOST_CHANGED) {
834 snprintf(msg, sizeof(msg),
835 "Warning: the %s host key for '%.200s' "
836 "differs from the key for the IP address '%.128s'"
837 "\nOffending key for IP in %s:%d",
838 type, host, ip, ip_file, ip_line);
839 if (host_status == HOST_OK) {
841 snprintf(msg + len, sizeof(msg) - len,
842 "\nMatching host key in %s:%d",
843 host_file, host_line);
845 if (options.strict_host_key_checking == 1) {
847 error("Exiting, you have requested strict checking.");
849 } else if (options.strict_host_key_checking == 2) {
850 strlcat(msg, "\nAre you sure you want "
851 "to continue connecting (yes/no)? ", sizeof(msg));
867 /* returns 0 if key verifies or -1 if key does NOT verify */
869 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
874 if (options.verify_host_key_dns &&
875 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
877 if (flags & DNS_VERIFY_FOUND) {
879 if (options.verify_host_key_dns == 1 &&
880 flags & DNS_VERIFY_MATCH &&
881 flags & DNS_VERIFY_SECURE)
884 if (flags & DNS_VERIFY_MATCH) {
885 matching_host_key_dns = 1;
887 warn_changed_key(host_key);
888 error("Update the SSHFP RR in DNS with the new "
889 "host key to get rid of this message.");
894 /* return ok if the key can be found in an old keyfile */
895 if (stat(options.system_hostfile2, &st) == 0 ||
896 stat(options.user_hostfile2, &st) == 0) {
897 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
898 options.user_hostfile2, options.system_hostfile2) == 0)
901 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
902 options.user_hostfile, options.system_hostfile);
906 * Starts a dialog with the server, and authenticates the current user on the
907 * server. This does not need any extra privileges. The basic connection
908 * to the server must already have been established before this is called.
909 * If login fails, this function prints an error and never returns.
910 * This function does not require super-user privileges.
913 ssh_login(Sensitive *sensitive, const char *orighost,
914 struct sockaddr *hostaddr, struct passwd *pw)
917 char *server_user, *local_user;
919 local_user = xstrdup(pw->pw_name);
920 server_user = options.user ? options.user : local_user;
922 /* Convert the user-supplied hostname into all lowercase. */
923 host = xstrdup(orighost);
924 for (cp = host; *cp; cp++)
928 /* Exchange protocol version identification strings with the server. */
929 ssh_exchange_identification();
931 /* Put the connection into non-blocking mode. */
932 packet_set_nonblocking();
935 /* authenticate user */
937 ssh_kex2(host, hostaddr);
938 ssh_userauth2(local_user, server_user, host, sensitive);
940 ssh_kex(host, hostaddr);
941 ssh_userauth1(local_user, server_user, host, sensitive);
946 ssh_put_password(char *password)
951 if (datafellows & SSH_BUG_PASSWORDPAD) {
952 packet_put_cstring(password);
955 size = roundup(strlen(password) + 1, 32);
956 padded = xmalloc(size);
957 memset(padded, 0, size);
958 strlcpy(padded, password, size);
959 packet_put_string(padded, size);
960 memset(padded, 0, size);
965 show_key_from_file(const char *file, const char *host, int keytype)
971 found = key_new(keytype);
972 if ((ret = lookup_key_in_hostfile_by_type(file, host,
973 keytype, found, &line))) {
974 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
975 logit("WARNING: %s key found for host %s\n"
977 "%s key fingerprint %s.",
978 key_type(found), host, file, line,
979 key_type(found), fp);
986 /* print all known host keys for a given host, but skip keys of given type */
988 show_other_keys(const char *host, Key *key)
990 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
993 for (i = 0; type[i] != -1; i++) {
994 if (type[i] == key->type)
996 if (type[i] != KEY_RSA1 &&
997 show_key_from_file(options.user_hostfile2, host, type[i])) {
1001 if (type[i] != KEY_RSA1 &&
1002 show_key_from_file(options.system_hostfile2, host, type[i])) {
1006 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1010 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1014 debug2("no key of type %d for host %s", type[i], host);
1020 warn_changed_key(Key *host_key)
1023 const char *type = key_type(host_key);
1025 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1027 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1028 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1029 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1030 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1031 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1032 error("It is also possible that the %s host key has just been changed.", type);
1033 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1035 error("Please contact your system administrator.");
1041 * Execute a local command
1044 ssh_local_cmd(const char *args)
1050 if (!options.permit_local_command ||
1051 args == NULL || !*args)
1054 if ((shell = getenv("SHELL")) == NULL)
1055 shell = _PATH_BSHELL;
1059 debug3("Executing %s -c \"%s\"", shell, args);
1060 execl(shell, shell, "-c", args, (char *)NULL);
1061 error("Couldn't execute %s -c \"%s\": %s",
1062 shell, args, strerror(errno));
1064 } else if (pid == -1)
1065 fatal("fork failed: %.100s", strerror(errno));
1066 while (waitpid(pid, &status, 0) == -1)
1068 fatal("Couldn't wait for child: %s", strerror(errno));
1070 if (!WIFEXITED(status))
1073 return (WEXITSTATUS(status));