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 1.171 2005/12/06 22:38:27 reyk Exp $");
18 #include <openssl/bn.h>
28 #include "sshconnect.h"
36 char *client_version_string = NULL;
37 char *server_version_string = NULL;
39 static int matching_host_key_dns = 0;
42 extern Options options;
43 extern char *__progname;
44 extern uid_t original_real_uid;
45 extern uid_t original_effective_uid;
46 extern pid_t proxy_command_pid;
48 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
49 #define INET6_ADDRSTRLEN 46
52 static int show_other_keys(const char *, Key *);
53 static void warn_changed_key(Key *);
56 * Connect to the given ssh server using a proxy command.
59 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
61 char *command_string, *tmp;
64 char strport[NI_MAXSERV];
67 /* Convert the port number into a string. */
68 snprintf(strport, sizeof strport, "%hu", port);
71 * Build the final command string in the buffer by making the
72 * appropriate substitutions to the given proxy command.
74 * Use "exec" to avoid "sh -c" processes on some platforms
77 len = strlen(proxy_command) + 6;
79 strlcpy(tmp, "exec ", len);
80 strlcat(tmp, proxy_command, len);
81 command_string = percent_expand(tmp, "h", host,
82 "p", strport, (char *)NULL);
85 /* Create pipes for communicating with the proxy. */
86 if (pipe(pin) < 0 || pipe(pout) < 0)
87 fatal("Could not create pipes to communicate with the proxy: %.100s",
90 debug("Executing proxy command: %.500s", command_string);
92 /* Fork and execute the proxy command. */
93 if ((pid = fork()) == 0) {
96 /* Child. Permanently give up superuser privileges. */
97 seteuid(original_real_uid);
98 setuid(original_real_uid);
100 /* Redirect stdin and stdout. */
103 if (dup2(pin[0], 0) < 0)
104 perror("dup2 stdin");
108 if (dup2(pout[1], 1) < 0)
109 perror("dup2 stdout");
110 /* Cannot be 1 because pin allocated two descriptors. */
113 /* Stderr is left as it is so that error messages get
114 printed on the user's terminal. */
115 argv[0] = _PATH_BSHELL;
117 argv[2] = command_string;
120 /* Execute the proxy command. Note that we gave up any
121 extra privileges above. */
122 execv(argv[0], argv);
128 fatal("fork failed: %.100s", strerror(errno));
130 proxy_command_pid = pid; /* save pid to clean up later */
132 /* Close child side of the descriptors. */
136 /* Free the command name. */
137 xfree(command_string);
139 /* Set the connection file descriptors. */
140 packet_set_connection(pout[0], pin[1]);
142 /* Indicate OK return */
147 * Creates a (possibly privileged) socket for use as the ssh connection.
150 ssh_create_socket(int privileged, struct addrinfo *ai)
153 struct addrinfo hints, *res;
156 * If we are running as root and want to connect to a privileged
157 * port, bind our own socket to a privileged port.
160 int p = IPPORT_RESERVED - 1;
162 sock = rresvport_af(&p, ai->ai_family);
165 error("rresvport: af=%d %.100s", ai->ai_family,
168 debug("Allocated local port %d.", p);
171 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
173 error("socket: %.100s", strerror(errno));
175 /* Bind the socket to an alternative local IP address */
176 if (options.bind_address == NULL)
179 memset(&hints, 0, sizeof(hints));
180 hints.ai_family = ai->ai_family;
181 hints.ai_socktype = ai->ai_socktype;
182 hints.ai_protocol = ai->ai_protocol;
183 hints.ai_flags = AI_PASSIVE;
184 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
186 error("getaddrinfo: %s: %s", options.bind_address,
187 gai_strerror(gaierr));
191 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
192 error("bind: %s: %s", options.bind_address, strerror(errno));
202 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
203 socklen_t addrlen, int timeout)
208 int fdsetsz, optval, rc, result = -1;
211 return (connect(sockfd, serv_addr, addrlen));
213 set_nonblock(sockfd);
214 rc = connect(sockfd, serv_addr, addrlen);
216 unset_nonblock(sockfd);
219 if (errno != EINPROGRESS)
222 fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
223 fdset = (fd_set *)xmalloc(fdsetsz);
225 memset(fdset, 0, fdsetsz);
226 FD_SET(sockfd, fdset);
231 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
232 if (rc != -1 || errno != EINTR)
243 debug("select: %s", strerror(errno));
246 /* Completed or failed */
248 optlen = sizeof(optval);
249 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
251 debug("getsockopt: %s", strerror(errno));
259 unset_nonblock(sockfd);
262 /* Should not occur */
263 fatal("Bogus return (%d) from select()", rc);
271 * Opens a TCP/IP connection to the remote server on the given host.
272 * The address of the remote host will be returned in hostaddr.
273 * If port is 0, the default port will be used. If needpriv is true,
274 * a privileged port will be allocated to make the connection.
275 * This requires super-user privileges if needpriv is true.
276 * Connection_attempts specifies the maximum number of tries (one per
277 * second). If proxy_command is non-NULL, it specifies the command (with %h
278 * and %p substituted for host and port, respectively) to use to contact
282 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
283 u_short port, int family, int connection_attempts,
284 int needpriv, const char *proxy_command)
288 int sock = -1, attempt;
289 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
290 struct addrinfo hints, *ai, *aitop;
292 debug2("ssh_connect: needpriv %d", needpriv);
294 /* If a proxy command is given, connect using it. */
295 if (proxy_command != NULL)
296 return ssh_proxy_connect(host, port, proxy_command);
298 /* No proxy command. */
300 memset(&hints, 0, sizeof(hints));
301 hints.ai_family = family;
302 hints.ai_socktype = SOCK_STREAM;
303 snprintf(strport, sizeof strport, "%u", port);
304 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
305 fatal("%s: %.100s: %s", __progname, host,
306 gai_strerror(gaierr));
309 * Try to connect several times. On some machines, the first time
310 * will sometimes fail. In general socket code appears to behave
311 * quite magically on many machines.
313 for (attempt = 0; ;) {
315 debug("Trying again...");
317 /* Loop through addresses for this host, and try each one in
318 sequence until the connection succeeds. */
319 for (ai = aitop; ai; ai = ai->ai_next) {
320 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
322 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
323 ntop, sizeof(ntop), strport, sizeof(strport),
324 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
325 error("ssh_connect: getnameinfo failed");
328 debug("Connecting to %.200s [%.100s] port %s.",
329 host, ntop, strport);
331 /* Create a socket for connecting. */
332 sock = ssh_create_socket(needpriv, ai);
334 /* Any error is already output */
337 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
338 options.connection_timeout) >= 0) {
339 /* Successful connection. */
340 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
343 debug("connect to address %s port %s: %s",
344 ntop, strport, strerror(errno));
346 * Close the failed socket; there appear to
347 * be some problems when reusing a socket for
348 * which connect() has already returned an
355 break; /* Successful connection. */
358 if (attempt >= connection_attempts)
360 /* Sleep a moment before retrying. */
366 /* Return failure if we didn't get a successful connection. */
367 if (attempt >= connection_attempts) {
368 error("ssh: connect to host %s port %s: %s",
369 host, strport, strerror(errno));
373 debug("Connection established.");
375 /* Set SO_KEEPALIVE if requested. */
376 if (options.tcp_keep_alive &&
377 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
379 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
381 /* Set the connection. */
382 packet_set_connection(sock, sock);
388 * Waits for the server identification string, and sends our own
389 * identification string.
392 ssh_exchange_identification(void)
394 char buf[256], remote_version[256]; /* must be same size! */
395 int remote_major, remote_minor, mismatch;
396 int connection_in = packet_get_connection_in();
397 int connection_out = packet_get_connection_out();
398 int minor1 = PROTOCOL_MINOR_1;
401 /* Read other side's version identification. */
403 for (i = 0; i < sizeof(buf) - 1; i++) {
404 size_t len = atomicio(read, connection_in, &buf[i], 1);
406 if (len != 1 && errno == EPIPE)
407 fatal("ssh_exchange_identification: Connection closed by remote host");
409 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
410 if (buf[i] == '\r') {
413 continue; /**XXX wait for \n */
415 if (buf[i] == '\n') {
420 buf[sizeof(buf) - 1] = 0;
421 if (strncmp(buf, "SSH-", 4) == 0)
423 debug("ssh_exchange_identification: %s", buf);
425 server_version_string = xstrdup(buf);
428 * Check that the versions match. In future this might accept
429 * several versions and set appropriate flags to handle them.
431 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
432 &remote_major, &remote_minor, remote_version) != 3)
433 fatal("Bad remote protocol version identification: '%.100s'", buf);
434 debug("Remote protocol version %d.%d, remote software version %.100s",
435 remote_major, remote_minor, remote_version);
437 compat_datafellows(remote_version);
440 switch (remote_major) {
442 if (remote_minor == 99 &&
443 (options.protocol & SSH_PROTO_2) &&
444 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
448 if (!(options.protocol & SSH_PROTO_1)) {
452 if (remote_minor < 3) {
453 fatal("Remote machine has too old SSH software version.");
454 } else if (remote_minor == 3 || remote_minor == 4) {
455 /* We speak 1.3, too. */
458 if (options.forward_agent) {
459 logit("Agent forwarding disabled for protocol 1.3");
460 options.forward_agent = 0;
465 if (options.protocol & SSH_PROTO_2) {
475 fatal("Protocol major versions differ: %d vs. %d",
476 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
478 /* Send our own protocol version identification. */
479 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
480 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
481 compat20 ? PROTOCOL_MINOR_2 : minor1,
483 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
484 fatal("write: %.100s", strerror(errno));
485 client_version_string = xstrdup(buf);
486 chop(client_version_string);
487 chop(server_version_string);
488 debug("Local version string %.100s", client_version_string);
491 /* defaults to 'no' */
493 confirm(const char *prompt)
495 const char *msg, *again = "Please type 'yes' or 'no': ";
499 if (options.batch_mode)
501 for (msg = prompt;;msg = again) {
502 p = read_passphrase(msg, RP_ECHO);
504 (p[0] == '\0') || (p[0] == '\n') ||
505 strncasecmp(p, "no", 2) == 0)
507 if (p && strncasecmp(p, "yes", 3) == 0)
517 * check whether the supplied host key is valid, return -1 if the key
518 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
521 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
522 int readonly, const char *user_hostfile, const char *system_hostfile)
525 const char *type = key_type(host_key);
527 char hostline[1000], *hostp, *fp;
528 HostStatus host_status;
529 HostStatus ip_status;
530 int r, local = 0, host_ip_differ = 0;
532 char ntop[NI_MAXHOST];
534 int len, host_line, ip_line;
535 const char *host_file = NULL, *ip_file = NULL;
538 * Force accepting of the host key for loopback/localhost. The
539 * problem is that if the home directory is NFS-mounted to multiple
540 * machines, localhost will refer to a different machine in each of
541 * them, and the user will get bogus HOST_CHANGED warnings. This
542 * essentially disables host authentication for localhost; however,
543 * this is probably not a real problem.
545 /** hostaddr == 0! */
546 switch (hostaddr->sa_family) {
548 local = (ntohl(((struct sockaddr_in *)hostaddr)->
549 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
550 salen = sizeof(struct sockaddr_in);
553 local = IN6_IS_ADDR_LOOPBACK(
554 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
555 salen = sizeof(struct sockaddr_in6);
559 salen = sizeof(struct sockaddr_storage);
562 if (options.no_host_authentication_for_localhost == 1 && local &&
563 options.host_key_alias == NULL) {
564 debug("Forcing accepting of host key for "
565 "loopback/localhost.");
570 * We don't have the remote ip-address for connections
571 * using a proxy command
573 if (options.proxy_command == NULL) {
574 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
575 NULL, 0, NI_NUMERICHOST) != 0)
576 fatal("check_host_key: getnameinfo failed");
579 ip = xstrdup("<no hostip for proxy command>");
582 * Turn off check_host_ip if the connection is to localhost, via proxy
583 * command or if we don't have a hostname to compare with
585 if (options.check_host_ip &&
586 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
587 options.check_host_ip = 0;
590 * Allow the user to record the key under a different name. This is
591 * useful for ssh tunneling over forwarded connections or if you run
592 * multiple sshd's on different ports on the same machine.
594 if (options.host_key_alias != NULL) {
595 host = options.host_key_alias;
596 debug("using hostkeyalias: %s", host);
600 * Store the host key from the known host file in here so that we can
601 * compare it with the key for the IP address.
603 file_key = key_new(host_key->type);
606 * Check if the host key is present in the user's list of known
607 * hosts or in the systemwide list.
609 host_file = user_hostfile;
610 host_status = check_host_in_hostfile(host_file, host, host_key,
611 file_key, &host_line);
612 if (host_status == HOST_NEW) {
613 host_file = system_hostfile;
614 host_status = check_host_in_hostfile(host_file, host, host_key,
615 file_key, &host_line);
618 * Also perform check for the ip address, skip the check if we are
619 * localhost or the hostname was an ip address to begin with
621 if (options.check_host_ip) {
622 Key *ip_key = key_new(host_key->type);
624 ip_file = user_hostfile;
625 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
627 if (ip_status == HOST_NEW) {
628 ip_file = system_hostfile;
629 ip_status = check_host_in_hostfile(ip_file, ip,
630 host_key, ip_key, &ip_line);
632 if (host_status == HOST_CHANGED &&
633 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
638 ip_status = host_status;
642 switch (host_status) {
644 /* The host is known and the key matches. */
645 debug("Host '%.200s' is known and matches the %s host key.",
647 debug("Found key in %s:%d", host_file, host_line);
648 if (options.check_host_ip && ip_status == HOST_NEW) {
650 logit("%s host key for IP address "
651 "'%.128s' not in list of known hosts.",
653 else if (!add_host_to_hostfile(user_hostfile, ip,
654 host_key, options.hash_known_hosts))
655 logit("Failed to add the %s host key for IP "
656 "address '%.128s' to the list of known "
657 "hosts (%.30s).", type, ip, user_hostfile);
659 logit("Warning: Permanently added the %s host "
660 "key for IP address '%.128s' to the list "
661 "of known hosts.", type, ip);
667 /* The host is new. */
668 if (options.strict_host_key_checking == 1) {
670 * User has requested strict host key checking. We
671 * will not add the host key automatically. The only
672 * alternative left is to abort.
674 error("No %s host key is known for %.200s and you "
675 "have requested strict checking.", type, host);
677 } else if (options.strict_host_key_checking == 2) {
678 char msg1[1024], msg2[1024];
680 if (show_other_keys(host, host_key))
681 snprintf(msg1, sizeof(msg1),
682 "\nbut keys of different type are already"
683 " known for this host.");
685 snprintf(msg1, sizeof(msg1), ".");
687 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
689 if (options.verify_host_key_dns) {
690 if (matching_host_key_dns)
691 snprintf(msg2, sizeof(msg2),
692 "Matching host key fingerprint"
695 snprintf(msg2, sizeof(msg2),
696 "No matching host key fingerprint"
699 snprintf(msg, sizeof(msg),
700 "The authenticity of host '%.200s (%s)' can't be "
702 "%s key fingerprint is %s.\n%s"
703 "Are you sure you want to continue connecting "
705 host, ip, msg1, type, fp, msg2);
711 * If not in strict mode, add the key automatically to the
712 * local known_hosts file.
714 if (options.check_host_ip && ip_status == HOST_NEW) {
715 snprintf(hostline, sizeof(hostline), "%s,%s",
718 if (options.hash_known_hosts) {
719 /* Add hash of host and IP separately */
720 r = add_host_to_hostfile(user_hostfile, host,
721 host_key, options.hash_known_hosts) &&
722 add_host_to_hostfile(user_hostfile, ip,
723 host_key, options.hash_known_hosts);
725 /* Add unhashed "host,ip" */
726 r = add_host_to_hostfile(user_hostfile,
728 options.hash_known_hosts);
731 r = add_host_to_hostfile(user_hostfile, host, host_key,
732 options.hash_known_hosts);
737 logit("Failed to add the host to the list of known "
738 "hosts (%.500s).", user_hostfile);
740 logit("Warning: Permanently added '%.200s' (%s) to the "
741 "list of known hosts.", hostp, type);
744 if (options.check_host_ip && host_ip_differ) {
746 if (ip_status == HOST_NEW)
747 key_msg = "is unknown";
748 else if (ip_status == HOST_OK)
749 key_msg = "is unchanged";
751 key_msg = "has a different value";
752 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
753 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
754 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
755 error("The %s host key for %s has changed,", type, host);
756 error("and the key for the according IP address %s", ip);
757 error("%s. This could either mean that", key_msg);
758 error("DNS SPOOFING is happening or the IP address for the host");
759 error("and its host key have changed at the same time.");
760 if (ip_status != HOST_NEW)
761 error("Offending key for IP in %s:%d", ip_file, ip_line);
763 /* The host key has changed. */
764 warn_changed_key(host_key);
765 error("Add correct host key in %.100s to get rid of this message.",
767 error("Offending key in %s:%d", host_file, host_line);
770 * If strict host key checking is in use, the user will have
771 * to edit the key manually and we can only abort.
773 if (options.strict_host_key_checking) {
774 error("%s host key for %.200s has changed and you have "
775 "requested strict checking.", type, host);
780 * If strict host key checking has not been requested, allow
781 * the connection but without MITM-able authentication or
784 if (options.password_authentication) {
785 error("Password authentication is disabled to avoid "
786 "man-in-the-middle attacks.");
787 options.password_authentication = 0;
789 if (options.kbd_interactive_authentication) {
790 error("Keyboard-interactive authentication is disabled"
791 " to avoid man-in-the-middle attacks.");
792 options.kbd_interactive_authentication = 0;
793 options.challenge_response_authentication = 0;
795 if (options.challenge_response_authentication) {
796 error("Challenge/response authentication is disabled"
797 " to avoid man-in-the-middle attacks.");
798 options.challenge_response_authentication = 0;
800 if (options.forward_agent) {
801 error("Agent forwarding is disabled to avoid "
802 "man-in-the-middle attacks.");
803 options.forward_agent = 0;
805 if (options.forward_x11) {
806 error("X11 forwarding is disabled to avoid "
807 "man-in-the-middle attacks.");
808 options.forward_x11 = 0;
810 if (options.num_local_forwards > 0 ||
811 options.num_remote_forwards > 0) {
812 error("Port forwarding is disabled to avoid "
813 "man-in-the-middle attacks.");
814 options.num_local_forwards =
815 options.num_remote_forwards = 0;
818 * XXX Should permit the user to change to use the new id.
819 * This could be done by converting the host key to an
820 * identifying sentence, tell that the host identifies itself
821 * by that sentence, and ask the user if he/she whishes to
822 * accept the authentication.
826 fatal("internal error");
830 if (options.check_host_ip && host_status != HOST_CHANGED &&
831 ip_status == HOST_CHANGED) {
832 snprintf(msg, sizeof(msg),
833 "Warning: the %s host key for '%.200s' "
834 "differs from the key for the IP address '%.128s'"
835 "\nOffending key for IP in %s:%d",
836 type, host, ip, ip_file, ip_line);
837 if (host_status == HOST_OK) {
839 snprintf(msg + len, sizeof(msg) - len,
840 "\nMatching host key in %s:%d",
841 host_file, host_line);
843 if (options.strict_host_key_checking == 1) {
845 error("Exiting, you have requested strict checking.");
847 } else if (options.strict_host_key_checking == 2) {
848 strlcat(msg, "\nAre you sure you want "
849 "to continue connecting (yes/no)? ", sizeof(msg));
865 /* returns 0 if key verifies or -1 if key does NOT verify */
867 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
872 if (options.verify_host_key_dns &&
873 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
875 if (flags & DNS_VERIFY_FOUND) {
877 if (options.verify_host_key_dns == 1 &&
878 flags & DNS_VERIFY_MATCH &&
879 flags & DNS_VERIFY_SECURE)
882 if (flags & DNS_VERIFY_MATCH) {
883 matching_host_key_dns = 1;
885 warn_changed_key(host_key);
886 error("Update the SSHFP RR in DNS with the new "
887 "host key to get rid of this message.");
892 /* return ok if the key can be found in an old keyfile */
893 if (stat(options.system_hostfile2, &st) == 0 ||
894 stat(options.user_hostfile2, &st) == 0) {
895 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
896 options.user_hostfile2, options.system_hostfile2) == 0)
899 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
900 options.user_hostfile, options.system_hostfile);
904 * Starts a dialog with the server, and authenticates the current user on the
905 * server. This does not need any extra privileges. The basic connection
906 * to the server must already have been established before this is called.
907 * If login fails, this function prints an error and never returns.
908 * This function does not require super-user privileges.
911 ssh_login(Sensitive *sensitive, const char *orighost,
912 struct sockaddr *hostaddr, struct passwd *pw)
915 char *server_user, *local_user;
917 local_user = xstrdup(pw->pw_name);
918 server_user = options.user ? options.user : local_user;
920 /* Convert the user-supplied hostname into all lowercase. */
921 host = xstrdup(orighost);
922 for (cp = host; *cp; cp++)
926 /* Exchange protocol version identification strings with the server. */
927 ssh_exchange_identification();
929 /* Put the connection into non-blocking mode. */
930 packet_set_nonblocking();
933 /* authenticate user */
935 ssh_kex2(host, hostaddr);
936 ssh_userauth2(local_user, server_user, host, sensitive);
938 ssh_kex(host, hostaddr);
939 ssh_userauth1(local_user, server_user, host, sensitive);
944 ssh_put_password(char *password)
949 if (datafellows & SSH_BUG_PASSWORDPAD) {
950 packet_put_cstring(password);
953 size = roundup(strlen(password) + 1, 32);
954 padded = xmalloc(size);
955 memset(padded, 0, size);
956 strlcpy(padded, password, size);
957 packet_put_string(padded, size);
958 memset(padded, 0, size);
963 show_key_from_file(const char *file, const char *host, int keytype)
969 found = key_new(keytype);
970 if ((ret = lookup_key_in_hostfile_by_type(file, host,
971 keytype, found, &line))) {
972 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
973 logit("WARNING: %s key found for host %s\n"
975 "%s key fingerprint %s.",
976 key_type(found), host, file, line,
977 key_type(found), fp);
984 /* print all known host keys for a given host, but skip keys of given type */
986 show_other_keys(const char *host, Key *key)
988 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
991 for (i = 0; type[i] != -1; i++) {
992 if (type[i] == key->type)
994 if (type[i] != KEY_RSA1 &&
995 show_key_from_file(options.user_hostfile2, host, type[i])) {
999 if (type[i] != KEY_RSA1 &&
1000 show_key_from_file(options.system_hostfile2, host, type[i])) {
1004 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1008 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1012 debug2("no key of type %d for host %s", type[i], host);
1018 warn_changed_key(Key *host_key)
1021 const char *type = key_type(host_key);
1023 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1025 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1026 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1027 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1028 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1029 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1030 error("It is also possible that the %s host key has just been changed.", type);
1031 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1033 error("Please contact your system administrator.");
1039 * Execute a local command
1042 ssh_local_cmd(const char *args)
1048 if (!options.permit_local_command ||
1049 args == NULL || !*args)
1052 if ((shell = getenv("SHELL")) == NULL)
1053 shell = _PATH_BSHELL;
1057 debug3("Executing %s -c \"%s\"", shell, args);
1058 execl(shell, shell, "-c", args, (char *)NULL);
1059 error("Couldn't execute %s -c \"%s\": %s",
1060 shell, args, strerror(errno));
1062 } else if (pid == -1)
1063 fatal("fork failed: %.100s", strerror(errno));
1064 while (waitpid(pid, &status, 0) == -1)
1066 fatal("Couldn't wait for child: %s", strerror(errno));
1068 if (!WIFEXITED(status))
1071 return (WEXITSTATUS(status));