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 1.176 2006/02/22 00:04:45 stevesk Exp $");
18 #include <sys/types.h>
33 #include "sshconnect.h"
41 char *client_version_string = NULL;
42 char *server_version_string = NULL;
44 static int matching_host_key_dns = 0;
47 extern Options options;
48 extern char *__progname;
49 extern uid_t original_real_uid;
50 extern uid_t original_effective_uid;
51 extern pid_t proxy_command_pid;
53 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
54 #define INET6_ADDRSTRLEN 46
57 static int show_other_keys(const char *, Key *);
58 static void warn_changed_key(Key *);
61 * Connect to the given ssh server using a proxy command.
64 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
66 char *command_string, *tmp;
69 char strport[NI_MAXSERV];
72 /* Convert the port number into a string. */
73 snprintf(strport, sizeof strport, "%hu", port);
76 * Build the final command string in the buffer by making the
77 * appropriate substitutions to the given proxy command.
79 * Use "exec" to avoid "sh -c" processes on some platforms
82 len = strlen(proxy_command) + 6;
84 strlcpy(tmp, "exec ", len);
85 strlcat(tmp, proxy_command, len);
86 command_string = percent_expand(tmp, "h", host,
87 "p", strport, (char *)NULL);
90 /* Create pipes for communicating with the proxy. */
91 if (pipe(pin) < 0 || pipe(pout) < 0)
92 fatal("Could not create pipes to communicate with the proxy: %.100s",
95 debug("Executing proxy command: %.500s", command_string);
97 /* Fork and execute the proxy command. */
98 if ((pid = fork()) == 0) {
101 /* Child. Permanently give up superuser privileges. */
102 seteuid(original_real_uid);
103 setuid(original_real_uid);
105 /* Redirect stdin and stdout. */
108 if (dup2(pin[0], 0) < 0)
109 perror("dup2 stdin");
113 if (dup2(pout[1], 1) < 0)
114 perror("dup2 stdout");
115 /* Cannot be 1 because pin allocated two descriptors. */
118 /* Stderr is left as it is so that error messages get
119 printed on the user's terminal. */
120 argv[0] = _PATH_BSHELL;
122 argv[2] = command_string;
125 /* Execute the proxy command. Note that we gave up any
126 extra privileges above. */
127 execv(argv[0], argv);
133 fatal("fork failed: %.100s", strerror(errno));
135 proxy_command_pid = pid; /* save pid to clean up later */
137 /* Close child side of the descriptors. */
141 /* Free the command name. */
142 xfree(command_string);
144 /* Set the connection file descriptors. */
145 packet_set_connection(pout[0], pin[1]);
147 /* Indicate OK return */
152 * Creates a (possibly privileged) socket for use as the ssh connection.
155 ssh_create_socket(int privileged, struct addrinfo *ai)
158 struct addrinfo hints, *res;
161 * If we are running as root and want to connect to a privileged
162 * port, bind our own socket to a privileged port.
165 int p = IPPORT_RESERVED - 1;
167 sock = rresvport_af(&p, ai->ai_family);
170 error("rresvport: af=%d %.100s", ai->ai_family,
173 debug("Allocated local port %d.", p);
176 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
178 error("socket: %.100s", strerror(errno));
180 /* Bind the socket to an alternative local IP address */
181 if (options.bind_address == NULL)
184 memset(&hints, 0, sizeof(hints));
185 hints.ai_family = ai->ai_family;
186 hints.ai_socktype = ai->ai_socktype;
187 hints.ai_protocol = ai->ai_protocol;
188 hints.ai_flags = AI_PASSIVE;
189 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
191 error("getaddrinfo: %s: %s", options.bind_address,
192 gai_strerror(gaierr));
196 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
197 error("bind: %s: %s", options.bind_address, strerror(errno));
207 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
208 socklen_t addrlen, int timeout)
213 int fdsetsz, optval, rc, result = -1;
216 return (connect(sockfd, serv_addr, addrlen));
218 set_nonblock(sockfd);
219 rc = connect(sockfd, serv_addr, addrlen);
221 unset_nonblock(sockfd);
224 if (errno != EINPROGRESS)
227 fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
228 fdset = (fd_set *)xmalloc(fdsetsz);
230 memset(fdset, 0, fdsetsz);
231 FD_SET(sockfd, fdset);
236 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
237 if (rc != -1 || errno != EINTR)
248 debug("select: %s", strerror(errno));
251 /* Completed or failed */
253 optlen = sizeof(optval);
254 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
256 debug("getsockopt: %s", strerror(errno));
264 unset_nonblock(sockfd);
267 /* Should not occur */
268 fatal("Bogus return (%d) from select()", rc);
276 * Opens a TCP/IP connection to the remote server on the given host.
277 * The address of the remote host will be returned in hostaddr.
278 * If port is 0, the default port will be used. If needpriv is true,
279 * a privileged port will be allocated to make the connection.
280 * This requires super-user privileges if needpriv is true.
281 * Connection_attempts specifies the maximum number of tries (one per
282 * second). If proxy_command is non-NULL, it specifies the command (with %h
283 * and %p substituted for host and port, respectively) to use to contact
287 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
288 u_short port, int family, int connection_attempts,
289 int needpriv, const char *proxy_command)
293 int sock = -1, attempt;
294 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
295 struct addrinfo hints, *ai, *aitop;
297 debug2("ssh_connect: needpriv %d", needpriv);
299 /* If a proxy command is given, connect using it. */
300 if (proxy_command != NULL)
301 return ssh_proxy_connect(host, port, proxy_command);
303 /* No proxy command. */
305 memset(&hints, 0, sizeof(hints));
306 hints.ai_family = family;
307 hints.ai_socktype = SOCK_STREAM;
308 snprintf(strport, sizeof strport, "%u", port);
309 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
310 fatal("%s: %.100s: %s", __progname, host,
311 gai_strerror(gaierr));
314 * Try to connect several times. On some machines, the first time
315 * will sometimes fail. In general socket code appears to behave
316 * quite magically on many machines.
318 for (attempt = 0; ;) {
320 debug("Trying again...");
322 /* Loop through addresses for this host, and try each one in
323 sequence until the connection succeeds. */
324 for (ai = aitop; ai; ai = ai->ai_next) {
325 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
327 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
328 ntop, sizeof(ntop), strport, sizeof(strport),
329 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
330 error("ssh_connect: getnameinfo failed");
333 debug("Connecting to %.200s [%.100s] port %s.",
334 host, ntop, strport);
336 /* Create a socket for connecting. */
337 sock = ssh_create_socket(needpriv, ai);
339 /* Any error is already output */
342 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
343 options.connection_timeout) >= 0) {
344 /* Successful connection. */
345 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
348 debug("connect to address %s port %s: %s",
349 ntop, strport, strerror(errno));
351 * Close the failed socket; there appear to
352 * be some problems when reusing a socket for
353 * which connect() has already returned an
360 break; /* Successful connection. */
363 if (attempt >= connection_attempts)
365 /* Sleep a moment before retrying. */
371 /* Return failure if we didn't get a successful connection. */
372 if (attempt >= connection_attempts) {
373 error("ssh: connect to host %s port %s: %s",
374 host, strport, strerror(errno));
378 debug("Connection established.");
380 /* Set SO_KEEPALIVE if requested. */
381 if (options.tcp_keep_alive &&
382 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
384 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
386 /* Set the connection. */
387 packet_set_connection(sock, sock);
393 * Waits for the server identification string, and sends our own
394 * identification string.
397 ssh_exchange_identification(void)
399 char buf[256], remote_version[256]; /* must be same size! */
400 int remote_major, remote_minor, mismatch;
401 int connection_in = packet_get_connection_in();
402 int connection_out = packet_get_connection_out();
403 int minor1 = PROTOCOL_MINOR_1;
406 /* Read other side's version identification. */
408 for (i = 0; i < sizeof(buf) - 1; i++) {
409 size_t len = atomicio(read, connection_in, &buf[i], 1);
411 if (len != 1 && errno == EPIPE)
412 fatal("ssh_exchange_identification: Connection closed by remote host");
414 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
415 if (buf[i] == '\r') {
418 continue; /**XXX wait for \n */
420 if (buf[i] == '\n') {
425 buf[sizeof(buf) - 1] = 0;
426 if (strncmp(buf, "SSH-", 4) == 0)
428 debug("ssh_exchange_identification: %s", buf);
430 server_version_string = xstrdup(buf);
433 * Check that the versions match. In future this might accept
434 * several versions and set appropriate flags to handle them.
436 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
437 &remote_major, &remote_minor, remote_version) != 3)
438 fatal("Bad remote protocol version identification: '%.100s'", buf);
439 debug("Remote protocol version %d.%d, remote software version %.100s",
440 remote_major, remote_minor, remote_version);
442 compat_datafellows(remote_version);
445 switch (remote_major) {
447 if (remote_minor == 99 &&
448 (options.protocol & SSH_PROTO_2) &&
449 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
453 if (!(options.protocol & SSH_PROTO_1)) {
457 if (remote_minor < 3) {
458 fatal("Remote machine has too old SSH software version.");
459 } else if (remote_minor == 3 || remote_minor == 4) {
460 /* We speak 1.3, too. */
463 if (options.forward_agent) {
464 logit("Agent forwarding disabled for protocol 1.3");
465 options.forward_agent = 0;
470 if (options.protocol & SSH_PROTO_2) {
480 fatal("Protocol major versions differ: %d vs. %d",
481 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
483 /* Send our own protocol version identification. */
484 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
485 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
486 compat20 ? PROTOCOL_MINOR_2 : minor1,
488 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
489 fatal("write: %.100s", strerror(errno));
490 client_version_string = xstrdup(buf);
491 chop(client_version_string);
492 chop(server_version_string);
493 debug("Local version string %.100s", client_version_string);
496 /* defaults to 'no' */
498 confirm(const char *prompt)
500 const char *msg, *again = "Please type 'yes' or 'no': ";
504 if (options.batch_mode)
506 for (msg = prompt;;msg = again) {
507 p = read_passphrase(msg, RP_ECHO);
509 (p[0] == '\0') || (p[0] == '\n') ||
510 strncasecmp(p, "no", 2) == 0)
512 if (p && strncasecmp(p, "yes", 3) == 0)
522 * check whether the supplied host key is valid, return -1 if the key
523 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
526 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
527 int readonly, const char *user_hostfile, const char *system_hostfile)
530 const char *type = key_type(host_key);
532 char hostline[1000], *hostp, *fp;
533 HostStatus host_status;
534 HostStatus ip_status;
535 int r, local = 0, host_ip_differ = 0;
537 char ntop[NI_MAXHOST];
539 int len, host_line, ip_line;
540 const char *host_file = NULL, *ip_file = NULL;
543 * Force accepting of the host key for loopback/localhost. The
544 * problem is that if the home directory is NFS-mounted to multiple
545 * machines, localhost will refer to a different machine in each of
546 * them, and the user will get bogus HOST_CHANGED warnings. This
547 * essentially disables host authentication for localhost; however,
548 * this is probably not a real problem.
550 /** hostaddr == 0! */
551 switch (hostaddr->sa_family) {
553 local = (ntohl(((struct sockaddr_in *)hostaddr)->
554 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
555 salen = sizeof(struct sockaddr_in);
558 local = IN6_IS_ADDR_LOOPBACK(
559 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
560 salen = sizeof(struct sockaddr_in6);
564 salen = sizeof(struct sockaddr_storage);
567 if (options.no_host_authentication_for_localhost == 1 && local &&
568 options.host_key_alias == NULL) {
569 debug("Forcing accepting of host key for "
570 "loopback/localhost.");
575 * We don't have the remote ip-address for connections
576 * using a proxy command
578 if (options.proxy_command == NULL) {
579 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
580 NULL, 0, NI_NUMERICHOST) != 0)
581 fatal("check_host_key: getnameinfo failed");
584 ip = xstrdup("<no hostip for proxy command>");
587 * Turn off check_host_ip if the connection is to localhost, via proxy
588 * command or if we don't have a hostname to compare with
590 if (options.check_host_ip &&
591 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
592 options.check_host_ip = 0;
595 * Allow the user to record the key under a different name. This is
596 * useful for ssh tunneling over forwarded connections or if you run
597 * multiple sshd's on different ports on the same machine.
599 if (options.host_key_alias != NULL) {
600 host = options.host_key_alias;
601 debug("using hostkeyalias: %s", host);
605 * Store the host key from the known host file in here so that we can
606 * compare it with the key for the IP address.
608 file_key = key_new(host_key->type);
611 * Check if the host key is present in the user's list of known
612 * hosts or in the systemwide list.
614 host_file = user_hostfile;
615 host_status = check_host_in_hostfile(host_file, host, host_key,
616 file_key, &host_line);
617 if (host_status == HOST_NEW) {
618 host_file = system_hostfile;
619 host_status = check_host_in_hostfile(host_file, host, host_key,
620 file_key, &host_line);
623 * Also perform check for the ip address, skip the check if we are
624 * localhost or the hostname was an ip address to begin with
626 if (options.check_host_ip) {
627 Key *ip_key = key_new(host_key->type);
629 ip_file = user_hostfile;
630 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
632 if (ip_status == HOST_NEW) {
633 ip_file = system_hostfile;
634 ip_status = check_host_in_hostfile(ip_file, ip,
635 host_key, ip_key, &ip_line);
637 if (host_status == HOST_CHANGED &&
638 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
643 ip_status = host_status;
647 switch (host_status) {
649 /* The host is known and the key matches. */
650 debug("Host '%.200s' is known and matches the %s host key.",
652 debug("Found key in %s:%d", host_file, host_line);
653 if (options.check_host_ip && ip_status == HOST_NEW) {
655 logit("%s host key for IP address "
656 "'%.128s' not in list of known hosts.",
658 else if (!add_host_to_hostfile(user_hostfile, ip,
659 host_key, options.hash_known_hosts))
660 logit("Failed to add the %s host key for IP "
661 "address '%.128s' to the list of known "
662 "hosts (%.30s).", type, ip, user_hostfile);
664 logit("Warning: Permanently added the %s host "
665 "key for IP address '%.128s' to the list "
666 "of known hosts.", type, ip);
672 /* The host is new. */
673 if (options.strict_host_key_checking == 1) {
675 * User has requested strict host key checking. We
676 * will not add the host key automatically. The only
677 * alternative left is to abort.
679 error("No %s host key is known for %.200s and you "
680 "have requested strict checking.", type, host);
682 } else if (options.strict_host_key_checking == 2) {
683 char msg1[1024], msg2[1024];
685 if (show_other_keys(host, host_key))
686 snprintf(msg1, sizeof(msg1),
687 "\nbut keys of different type are already"
688 " known for this host.");
690 snprintf(msg1, sizeof(msg1), ".");
692 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
694 if (options.verify_host_key_dns) {
695 if (matching_host_key_dns)
696 snprintf(msg2, sizeof(msg2),
697 "Matching host key fingerprint"
700 snprintf(msg2, sizeof(msg2),
701 "No matching host key fingerprint"
704 snprintf(msg, sizeof(msg),
705 "The authenticity of host '%.200s (%s)' can't be "
707 "%s key fingerprint is %s.\n%s"
708 "Are you sure you want to continue connecting "
710 host, ip, msg1, type, fp, msg2);
716 * If not in strict mode, add the key automatically to the
717 * local known_hosts file.
719 if (options.check_host_ip && ip_status == HOST_NEW) {
720 snprintf(hostline, sizeof(hostline), "%s,%s",
723 if (options.hash_known_hosts) {
724 /* Add hash of host and IP separately */
725 r = add_host_to_hostfile(user_hostfile, host,
726 host_key, options.hash_known_hosts) &&
727 add_host_to_hostfile(user_hostfile, ip,
728 host_key, options.hash_known_hosts);
730 /* Add unhashed "host,ip" */
731 r = add_host_to_hostfile(user_hostfile,
733 options.hash_known_hosts);
736 r = add_host_to_hostfile(user_hostfile, host, host_key,
737 options.hash_known_hosts);
742 logit("Failed to add the host to the list of known "
743 "hosts (%.500s).", user_hostfile);
745 logit("Warning: Permanently added '%.200s' (%s) to the "
746 "list of known hosts.", hostp, type);
749 if (options.check_host_ip && host_ip_differ) {
751 if (ip_status == HOST_NEW)
752 key_msg = "is unknown";
753 else if (ip_status == HOST_OK)
754 key_msg = "is unchanged";
756 key_msg = "has a different value";
757 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
758 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
759 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
760 error("The %s host key for %s has changed,", type, host);
761 error("and the key for the according IP address %s", ip);
762 error("%s. This could either mean that", key_msg);
763 error("DNS SPOOFING is happening or the IP address for the host");
764 error("and its host key have changed at the same time.");
765 if (ip_status != HOST_NEW)
766 error("Offending key for IP in %s:%d", ip_file, ip_line);
768 /* The host key has changed. */
769 warn_changed_key(host_key);
770 error("Add correct host key in %.100s to get rid of this message.",
772 error("Offending key in %s:%d", host_file, host_line);
775 * If strict host key checking is in use, the user will have
776 * to edit the key manually and we can only abort.
778 if (options.strict_host_key_checking) {
779 error("%s host key for %.200s has changed and you have "
780 "requested strict checking.", type, host);
785 * If strict host key checking has not been requested, allow
786 * the connection but without MITM-able authentication or
789 if (options.password_authentication) {
790 error("Password authentication is disabled to avoid "
791 "man-in-the-middle attacks.");
792 options.password_authentication = 0;
794 if (options.kbd_interactive_authentication) {
795 error("Keyboard-interactive authentication is disabled"
796 " to avoid man-in-the-middle attacks.");
797 options.kbd_interactive_authentication = 0;
798 options.challenge_response_authentication = 0;
800 if (options.challenge_response_authentication) {
801 error("Challenge/response authentication is disabled"
802 " to avoid man-in-the-middle attacks.");
803 options.challenge_response_authentication = 0;
805 if (options.forward_agent) {
806 error("Agent forwarding is disabled to avoid "
807 "man-in-the-middle attacks.");
808 options.forward_agent = 0;
810 if (options.forward_x11) {
811 error("X11 forwarding is disabled to avoid "
812 "man-in-the-middle attacks.");
813 options.forward_x11 = 0;
815 if (options.num_local_forwards > 0 ||
816 options.num_remote_forwards > 0) {
817 error("Port forwarding is disabled to avoid "
818 "man-in-the-middle attacks.");
819 options.num_local_forwards =
820 options.num_remote_forwards = 0;
823 * XXX Should permit the user to change to use the new id.
824 * This could be done by converting the host key to an
825 * identifying sentence, tell that the host identifies itself
826 * by that sentence, and ask the user if he/she whishes to
827 * accept the authentication.
831 fatal("internal error");
835 if (options.check_host_ip && host_status != HOST_CHANGED &&
836 ip_status == HOST_CHANGED) {
837 snprintf(msg, sizeof(msg),
838 "Warning: the %s host key for '%.200s' "
839 "differs from the key for the IP address '%.128s'"
840 "\nOffending key for IP in %s:%d",
841 type, host, ip, ip_file, ip_line);
842 if (host_status == HOST_OK) {
844 snprintf(msg + len, sizeof(msg) - len,
845 "\nMatching host key in %s:%d",
846 host_file, host_line);
848 if (options.strict_host_key_checking == 1) {
850 error("Exiting, you have requested strict checking.");
852 } else if (options.strict_host_key_checking == 2) {
853 strlcat(msg, "\nAre you sure you want "
854 "to continue connecting (yes/no)? ", sizeof(msg));
870 /* returns 0 if key verifies or -1 if key does NOT verify */
872 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
877 if (options.verify_host_key_dns &&
878 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
880 if (flags & DNS_VERIFY_FOUND) {
882 if (options.verify_host_key_dns == 1 &&
883 flags & DNS_VERIFY_MATCH &&
884 flags & DNS_VERIFY_SECURE)
887 if (flags & DNS_VERIFY_MATCH) {
888 matching_host_key_dns = 1;
890 warn_changed_key(host_key);
891 error("Update the SSHFP RR in DNS with the new "
892 "host key to get rid of this message.");
897 /* return ok if the key can be found in an old keyfile */
898 if (stat(options.system_hostfile2, &st) == 0 ||
899 stat(options.user_hostfile2, &st) == 0) {
900 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
901 options.user_hostfile2, options.system_hostfile2) == 0)
904 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
905 options.user_hostfile, options.system_hostfile);
909 * Starts a dialog with the server, and authenticates the current user on the
910 * server. This does not need any extra privileges. The basic connection
911 * to the server must already have been established before this is called.
912 * If login fails, this function prints an error and never returns.
913 * This function does not require super-user privileges.
916 ssh_login(Sensitive *sensitive, const char *orighost,
917 struct sockaddr *hostaddr, struct passwd *pw)
920 char *server_user, *local_user;
922 local_user = xstrdup(pw->pw_name);
923 server_user = options.user ? options.user : local_user;
925 /* Convert the user-supplied hostname into all lowercase. */
926 host = xstrdup(orighost);
927 for (cp = host; *cp; cp++)
931 /* Exchange protocol version identification strings with the server. */
932 ssh_exchange_identification();
934 /* Put the connection into non-blocking mode. */
935 packet_set_nonblocking();
938 /* authenticate user */
940 ssh_kex2(host, hostaddr);
941 ssh_userauth2(local_user, server_user, host, sensitive);
943 ssh_kex(host, hostaddr);
944 ssh_userauth1(local_user, server_user, host, sensitive);
949 ssh_put_password(char *password)
954 if (datafellows & SSH_BUG_PASSWORDPAD) {
955 packet_put_cstring(password);
958 size = roundup(strlen(password) + 1, 32);
959 padded = xmalloc(size);
960 memset(padded, 0, size);
961 strlcpy(padded, password, size);
962 packet_put_string(padded, size);
963 memset(padded, 0, size);
968 show_key_from_file(const char *file, const char *host, int keytype)
974 found = key_new(keytype);
975 if ((ret = lookup_key_in_hostfile_by_type(file, host,
976 keytype, found, &line))) {
977 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
978 logit("WARNING: %s key found for host %s\n"
980 "%s key fingerprint %s.",
981 key_type(found), host, file, line,
982 key_type(found), fp);
989 /* print all known host keys for a given host, but skip keys of given type */
991 show_other_keys(const char *host, Key *key)
993 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
996 for (i = 0; type[i] != -1; i++) {
997 if (type[i] == key->type)
999 if (type[i] != KEY_RSA1 &&
1000 show_key_from_file(options.user_hostfile2, host, type[i])) {
1004 if (type[i] != KEY_RSA1 &&
1005 show_key_from_file(options.system_hostfile2, host, type[i])) {
1009 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1013 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1017 debug2("no key of type %d for host %s", type[i], host);
1023 warn_changed_key(Key *host_key)
1026 const char *type = key_type(host_key);
1028 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1030 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1031 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1032 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1033 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1034 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1035 error("It is also possible that the %s host key has just been changed.", type);
1036 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1038 error("Please contact your system administrator.");
1044 * Execute a local command
1047 ssh_local_cmd(const char *args)
1053 if (!options.permit_local_command ||
1054 args == NULL || !*args)
1057 if ((shell = getenv("SHELL")) == NULL)
1058 shell = _PATH_BSHELL;
1062 debug3("Executing %s -c \"%s\"", shell, args);
1063 execl(shell, shell, "-c", args, (char *)NULL);
1064 error("Couldn't execute %s -c \"%s\": %s",
1065 shell, args, strerror(errno));
1067 } else if (pid == -1)
1068 fatal("fork failed: %.100s", strerror(errno));
1069 while (waitpid(pid, &status, 0) == -1)
1071 fatal("Couldn't wait for child: %s", strerror(errno));
1073 if (!WIFEXITED(status))
1076 return (WEXITSTATUS(status));