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>
35 #include "sshconnect.h"
43 char *client_version_string = NULL;
44 char *server_version_string = NULL;
46 static int matching_host_key_dns = 0;
49 extern Options options;
50 extern char *__progname;
51 extern uid_t original_real_uid;
52 extern uid_t original_effective_uid;
53 extern pid_t proxy_command_pid;
55 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
56 #define INET6_ADDRSTRLEN 46
59 static int show_other_keys(const char *, Key *);
60 static void warn_changed_key(Key *);
63 * Connect to the given ssh server using a proxy command.
66 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
68 char *command_string, *tmp;
71 char strport[NI_MAXSERV];
74 /* Convert the port number into a string. */
75 snprintf(strport, sizeof strport, "%hu", port);
78 * Build the final command string in the buffer by making the
79 * appropriate substitutions to the given proxy command.
81 * Use "exec" to avoid "sh -c" processes on some platforms
84 len = strlen(proxy_command) + 6;
86 strlcpy(tmp, "exec ", len);
87 strlcat(tmp, proxy_command, len);
88 command_string = percent_expand(tmp, "h", host,
89 "p", strport, (char *)NULL);
92 /* Create pipes for communicating with the proxy. */
93 if (pipe(pin) < 0 || pipe(pout) < 0)
94 fatal("Could not create pipes to communicate with the proxy: %.100s",
97 debug("Executing proxy command: %.500s", command_string);
99 /* Fork and execute the proxy command. */
100 if ((pid = fork()) == 0) {
103 /* Child. Permanently give up superuser privileges. */
104 seteuid(original_real_uid);
105 setuid(original_real_uid);
107 /* Redirect stdin and stdout. */
110 if (dup2(pin[0], 0) < 0)
111 perror("dup2 stdin");
115 if (dup2(pout[1], 1) < 0)
116 perror("dup2 stdout");
117 /* Cannot be 1 because pin allocated two descriptors. */
120 /* Stderr is left as it is so that error messages get
121 printed on the user's terminal. */
122 argv[0] = _PATH_BSHELL;
124 argv[2] = command_string;
127 /* Execute the proxy command. Note that we gave up any
128 extra privileges above. */
129 execv(argv[0], argv);
135 fatal("fork failed: %.100s", strerror(errno));
137 proxy_command_pid = pid; /* save pid to clean up later */
139 /* Close child side of the descriptors. */
143 /* Free the command name. */
144 xfree(command_string);
146 /* Set the connection file descriptors. */
147 packet_set_connection(pout[0], pin[1]);
149 /* Indicate OK return */
154 * Creates a (possibly privileged) socket for use as the ssh connection.
157 ssh_create_socket(int privileged, struct addrinfo *ai)
160 struct addrinfo hints, *res;
163 * If we are running as root and want to connect to a privileged
164 * port, bind our own socket to a privileged port.
167 int p = IPPORT_RESERVED - 1;
169 sock = rresvport_af(&p, ai->ai_family);
172 error("rresvport: af=%d %.100s", ai->ai_family,
175 debug("Allocated local port %d.", p);
178 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
180 error("socket: %.100s", strerror(errno));
182 /* Bind the socket to an alternative local IP address */
183 if (options.bind_address == NULL)
186 memset(&hints, 0, sizeof(hints));
187 hints.ai_family = ai->ai_family;
188 hints.ai_socktype = ai->ai_socktype;
189 hints.ai_protocol = ai->ai_protocol;
190 hints.ai_flags = AI_PASSIVE;
191 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
193 error("getaddrinfo: %s: %s", options.bind_address,
194 gai_strerror(gaierr));
198 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
199 error("bind: %s: %s", options.bind_address, strerror(errno));
209 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
210 socklen_t addrlen, int timeout)
215 int fdsetsz, optval, rc, result = -1;
218 return (connect(sockfd, serv_addr, addrlen));
220 set_nonblock(sockfd);
221 rc = connect(sockfd, serv_addr, addrlen);
223 unset_nonblock(sockfd);
226 if (errno != EINPROGRESS)
229 fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
230 fdset = (fd_set *)xmalloc(fdsetsz);
232 memset(fdset, 0, fdsetsz);
233 FD_SET(sockfd, fdset);
238 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
239 if (rc != -1 || errno != EINTR)
250 debug("select: %s", strerror(errno));
253 /* Completed or failed */
255 optlen = sizeof(optval);
256 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
258 debug("getsockopt: %s", strerror(errno));
266 unset_nonblock(sockfd);
269 /* Should not occur */
270 fatal("Bogus return (%d) from select()", rc);
278 * Opens a TCP/IP connection to the remote server on the given host.
279 * The address of the remote host will be returned in hostaddr.
280 * If port is 0, the default port will be used. If needpriv is true,
281 * a privileged port will be allocated to make the connection.
282 * This requires super-user privileges if needpriv is true.
283 * Connection_attempts specifies the maximum number of tries (one per
284 * second). If proxy_command is non-NULL, it specifies the command (with %h
285 * and %p substituted for host and port, respectively) to use to contact
289 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
290 u_short port, int family, int connection_attempts,
291 int needpriv, const char *proxy_command)
295 int sock = -1, attempt;
296 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
297 struct addrinfo hints, *ai, *aitop;
299 debug2("ssh_connect: needpriv %d", needpriv);
301 /* If a proxy command is given, connect using it. */
302 if (proxy_command != NULL)
303 return ssh_proxy_connect(host, port, proxy_command);
305 /* No proxy command. */
307 memset(&hints, 0, sizeof(hints));
308 hints.ai_family = family;
309 hints.ai_socktype = SOCK_STREAM;
310 snprintf(strport, sizeof strport, "%u", port);
311 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
312 fatal("%s: %.100s: %s", __progname, host,
313 gai_strerror(gaierr));
316 * Try to connect several times. On some machines, the first time
317 * will sometimes fail. In general socket code appears to behave
318 * quite magically on many machines.
320 for (attempt = 0; ;) {
322 debug("Trying again...");
324 /* Loop through addresses for this host, and try each one in
325 sequence until the connection succeeds. */
326 for (ai = aitop; ai; ai = ai->ai_next) {
327 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
329 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
330 ntop, sizeof(ntop), strport, sizeof(strport),
331 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
332 error("ssh_connect: getnameinfo failed");
335 debug("Connecting to %.200s [%.100s] port %s.",
336 host, ntop, strport);
338 /* Create a socket for connecting. */
339 sock = ssh_create_socket(needpriv, ai);
341 /* Any error is already output */
344 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
345 options.connection_timeout) >= 0) {
346 /* Successful connection. */
347 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
350 debug("connect to address %s port %s: %s",
351 ntop, strport, strerror(errno));
353 * Close the failed socket; there appear to
354 * be some problems when reusing a socket for
355 * which connect() has already returned an
362 break; /* Successful connection. */
365 if (attempt >= connection_attempts)
367 /* Sleep a moment before retrying. */
373 /* Return failure if we didn't get a successful connection. */
374 if (attempt >= connection_attempts) {
375 error("ssh: connect to host %s port %s: %s",
376 host, strport, strerror(errno));
380 debug("Connection established.");
382 /* Set SO_KEEPALIVE if requested. */
383 if (options.tcp_keep_alive &&
384 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
386 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
388 /* Set the connection. */
389 packet_set_connection(sock, sock);
395 * Waits for the server identification string, and sends our own
396 * identification string.
399 ssh_exchange_identification(void)
401 char buf[256], remote_version[256]; /* must be same size! */
402 int remote_major, remote_minor, mismatch;
403 int connection_in = packet_get_connection_in();
404 int connection_out = packet_get_connection_out();
405 int minor1 = PROTOCOL_MINOR_1;
408 /* Read other side's version identification. */
410 for (i = 0; i < sizeof(buf) - 1; i++) {
411 size_t len = atomicio(read, connection_in, &buf[i], 1);
413 if (len != 1 && errno == EPIPE)
414 fatal("ssh_exchange_identification: Connection closed by remote host");
416 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
417 if (buf[i] == '\r') {
420 continue; /**XXX wait for \n */
422 if (buf[i] == '\n') {
427 buf[sizeof(buf) - 1] = 0;
428 if (strncmp(buf, "SSH-", 4) == 0)
430 debug("ssh_exchange_identification: %s", buf);
432 server_version_string = xstrdup(buf);
435 * Check that the versions match. In future this might accept
436 * several versions and set appropriate flags to handle them.
438 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
439 &remote_major, &remote_minor, remote_version) != 3)
440 fatal("Bad remote protocol version identification: '%.100s'", buf);
441 debug("Remote protocol version %d.%d, remote software version %.100s",
442 remote_major, remote_minor, remote_version);
444 compat_datafellows(remote_version);
447 switch (remote_major) {
449 if (remote_minor == 99 &&
450 (options.protocol & SSH_PROTO_2) &&
451 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
455 if (!(options.protocol & SSH_PROTO_1)) {
459 if (remote_minor < 3) {
460 fatal("Remote machine has too old SSH software version.");
461 } else if (remote_minor == 3 || remote_minor == 4) {
462 /* We speak 1.3, too. */
465 if (options.forward_agent) {
466 logit("Agent forwarding disabled for protocol 1.3");
467 options.forward_agent = 0;
472 if (options.protocol & SSH_PROTO_2) {
482 fatal("Protocol major versions differ: %d vs. %d",
483 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
485 /* Send our own protocol version identification. */
486 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
487 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
488 compat20 ? PROTOCOL_MINOR_2 : minor1,
490 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
491 fatal("write: %.100s", strerror(errno));
492 client_version_string = xstrdup(buf);
493 chop(client_version_string);
494 chop(server_version_string);
495 debug("Local version string %.100s", client_version_string);
498 /* defaults to 'no' */
500 confirm(const char *prompt)
502 const char *msg, *again = "Please type 'yes' or 'no': ";
506 if (options.batch_mode)
508 for (msg = prompt;;msg = again) {
509 p = read_passphrase(msg, RP_ECHO);
511 (p[0] == '\0') || (p[0] == '\n') ||
512 strncasecmp(p, "no", 2) == 0)
514 if (p && strncasecmp(p, "yes", 3) == 0)
524 * check whether the supplied host key is valid, return -1 if the key
525 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
528 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
529 int readonly, const char *user_hostfile, const char *system_hostfile)
532 const char *type = key_type(host_key);
534 char hostline[1000], *hostp, *fp;
535 HostStatus host_status;
536 HostStatus ip_status;
537 int r, local = 0, host_ip_differ = 0;
539 char ntop[NI_MAXHOST];
541 int len, host_line, ip_line;
542 const char *host_file = NULL, *ip_file = NULL;
545 * Force accepting of the host key for loopback/localhost. The
546 * problem is that if the home directory is NFS-mounted to multiple
547 * machines, localhost will refer to a different machine in each of
548 * them, and the user will get bogus HOST_CHANGED warnings. This
549 * essentially disables host authentication for localhost; however,
550 * this is probably not a real problem.
552 /** hostaddr == 0! */
553 switch (hostaddr->sa_family) {
555 local = (ntohl(((struct sockaddr_in *)hostaddr)->
556 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
557 salen = sizeof(struct sockaddr_in);
560 local = IN6_IS_ADDR_LOOPBACK(
561 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
562 salen = sizeof(struct sockaddr_in6);
566 salen = sizeof(struct sockaddr_storage);
569 if (options.no_host_authentication_for_localhost == 1 && local &&
570 options.host_key_alias == NULL) {
571 debug("Forcing accepting of host key for "
572 "loopback/localhost.");
577 * We don't have the remote ip-address for connections
578 * using a proxy command
580 if (options.proxy_command == NULL) {
581 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
582 NULL, 0, NI_NUMERICHOST) != 0)
583 fatal("check_host_key: getnameinfo failed");
586 ip = xstrdup("<no hostip for proxy command>");
589 * Turn off check_host_ip if the connection is to localhost, via proxy
590 * command or if we don't have a hostname to compare with
592 if (options.check_host_ip &&
593 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
594 options.check_host_ip = 0;
597 * Allow the user to record the key under a different name. This is
598 * useful for ssh tunneling over forwarded connections or if you run
599 * multiple sshd's on different ports on the same machine.
601 if (options.host_key_alias != NULL) {
602 host = options.host_key_alias;
603 debug("using hostkeyalias: %s", host);
607 * Store the host key from the known host file in here so that we can
608 * compare it with the key for the IP address.
610 file_key = key_new(host_key->type);
613 * Check if the host key is present in the user's list of known
614 * hosts or in the systemwide list.
616 host_file = user_hostfile;
617 host_status = check_host_in_hostfile(host_file, host, host_key,
618 file_key, &host_line);
619 if (host_status == HOST_NEW) {
620 host_file = system_hostfile;
621 host_status = check_host_in_hostfile(host_file, host, host_key,
622 file_key, &host_line);
625 * Also perform check for the ip address, skip the check if we are
626 * localhost or the hostname was an ip address to begin with
628 if (options.check_host_ip) {
629 Key *ip_key = key_new(host_key->type);
631 ip_file = user_hostfile;
632 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
634 if (ip_status == HOST_NEW) {
635 ip_file = system_hostfile;
636 ip_status = check_host_in_hostfile(ip_file, ip,
637 host_key, ip_key, &ip_line);
639 if (host_status == HOST_CHANGED &&
640 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
645 ip_status = host_status;
649 switch (host_status) {
651 /* The host is known and the key matches. */
652 debug("Host '%.200s' is known and matches the %s host key.",
654 debug("Found key in %s:%d", host_file, host_line);
655 if (options.check_host_ip && ip_status == HOST_NEW) {
657 logit("%s host key for IP address "
658 "'%.128s' not in list of known hosts.",
660 else if (!add_host_to_hostfile(user_hostfile, ip,
661 host_key, options.hash_known_hosts))
662 logit("Failed to add the %s host key for IP "
663 "address '%.128s' to the list of known "
664 "hosts (%.30s).", type, ip, user_hostfile);
666 logit("Warning: Permanently added the %s host "
667 "key for IP address '%.128s' to the list "
668 "of known hosts.", type, ip);
674 /* The host is new. */
675 if (options.strict_host_key_checking == 1) {
677 * User has requested strict host key checking. We
678 * will not add the host key automatically. The only
679 * alternative left is to abort.
681 error("No %s host key is known for %.200s and you "
682 "have requested strict checking.", type, host);
684 } else if (options.strict_host_key_checking == 2) {
685 char msg1[1024], msg2[1024];
687 if (show_other_keys(host, host_key))
688 snprintf(msg1, sizeof(msg1),
689 "\nbut keys of different type are already"
690 " known for this host.");
692 snprintf(msg1, sizeof(msg1), ".");
694 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
696 if (options.verify_host_key_dns) {
697 if (matching_host_key_dns)
698 snprintf(msg2, sizeof(msg2),
699 "Matching host key fingerprint"
702 snprintf(msg2, sizeof(msg2),
703 "No matching host key fingerprint"
706 snprintf(msg, sizeof(msg),
707 "The authenticity of host '%.200s (%s)' can't be "
709 "%s key fingerprint is %s.\n%s"
710 "Are you sure you want to continue connecting "
712 host, ip, msg1, type, fp, msg2);
718 * If not in strict mode, add the key automatically to the
719 * local known_hosts file.
721 if (options.check_host_ip && ip_status == HOST_NEW) {
722 snprintf(hostline, sizeof(hostline), "%s,%s",
725 if (options.hash_known_hosts) {
726 /* Add hash of host and IP separately */
727 r = add_host_to_hostfile(user_hostfile, host,
728 host_key, options.hash_known_hosts) &&
729 add_host_to_hostfile(user_hostfile, ip,
730 host_key, options.hash_known_hosts);
732 /* Add unhashed "host,ip" */
733 r = add_host_to_hostfile(user_hostfile,
735 options.hash_known_hosts);
738 r = add_host_to_hostfile(user_hostfile, host, host_key,
739 options.hash_known_hosts);
744 logit("Failed to add the host to the list of known "
745 "hosts (%.500s).", user_hostfile);
747 logit("Warning: Permanently added '%.200s' (%s) to the "
748 "list of known hosts.", hostp, type);
751 if (options.check_host_ip && host_ip_differ) {
753 if (ip_status == HOST_NEW)
754 key_msg = "is unknown";
755 else if (ip_status == HOST_OK)
756 key_msg = "is unchanged";
758 key_msg = "has a different value";
759 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
760 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
761 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
762 error("The %s host key for %s has changed,", type, host);
763 error("and the key for the according IP address %s", ip);
764 error("%s. This could either mean that", key_msg);
765 error("DNS SPOOFING is happening or the IP address for the host");
766 error("and its host key have changed at the same time.");
767 if (ip_status != HOST_NEW)
768 error("Offending key for IP in %s:%d", ip_file, ip_line);
770 /* The host key has changed. */
771 warn_changed_key(host_key);
772 error("Add correct host key in %.100s to get rid of this message.",
774 error("Offending key in %s:%d", host_file, host_line);
777 * If strict host key checking is in use, the user will have
778 * to edit the key manually and we can only abort.
780 if (options.strict_host_key_checking) {
781 error("%s host key for %.200s has changed and you have "
782 "requested strict checking.", type, host);
787 * If strict host key checking has not been requested, allow
788 * the connection but without MITM-able authentication or
791 if (options.password_authentication) {
792 error("Password authentication is disabled to avoid "
793 "man-in-the-middle attacks.");
794 options.password_authentication = 0;
796 if (options.kbd_interactive_authentication) {
797 error("Keyboard-interactive authentication is disabled"
798 " to avoid man-in-the-middle attacks.");
799 options.kbd_interactive_authentication = 0;
800 options.challenge_response_authentication = 0;
802 if (options.challenge_response_authentication) {
803 error("Challenge/response authentication is disabled"
804 " to avoid man-in-the-middle attacks.");
805 options.challenge_response_authentication = 0;
807 if (options.forward_agent) {
808 error("Agent forwarding is disabled to avoid "
809 "man-in-the-middle attacks.");
810 options.forward_agent = 0;
812 if (options.forward_x11) {
813 error("X11 forwarding is disabled to avoid "
814 "man-in-the-middle attacks.");
815 options.forward_x11 = 0;
817 if (options.num_local_forwards > 0 ||
818 options.num_remote_forwards > 0) {
819 error("Port forwarding is disabled to avoid "
820 "man-in-the-middle attacks.");
821 options.num_local_forwards =
822 options.num_remote_forwards = 0;
825 * XXX Should permit the user to change to use the new id.
826 * This could be done by converting the host key to an
827 * identifying sentence, tell that the host identifies itself
828 * by that sentence, and ask the user if he/she whishes to
829 * accept the authentication.
833 fatal("internal error");
837 if (options.check_host_ip && host_status != HOST_CHANGED &&
838 ip_status == HOST_CHANGED) {
839 snprintf(msg, sizeof(msg),
840 "Warning: the %s host key for '%.200s' "
841 "differs from the key for the IP address '%.128s'"
842 "\nOffending key for IP in %s:%d",
843 type, host, ip, ip_file, ip_line);
844 if (host_status == HOST_OK) {
846 snprintf(msg + len, sizeof(msg) - len,
847 "\nMatching host key in %s:%d",
848 host_file, host_line);
850 if (options.strict_host_key_checking == 1) {
852 error("Exiting, you have requested strict checking.");
854 } else if (options.strict_host_key_checking == 2) {
855 strlcat(msg, "\nAre you sure you want "
856 "to continue connecting (yes/no)? ", sizeof(msg));
872 /* returns 0 if key verifies or -1 if key does NOT verify */
874 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
879 if (options.verify_host_key_dns &&
880 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
882 if (flags & DNS_VERIFY_FOUND) {
884 if (options.verify_host_key_dns == 1 &&
885 flags & DNS_VERIFY_MATCH &&
886 flags & DNS_VERIFY_SECURE)
889 if (flags & DNS_VERIFY_MATCH) {
890 matching_host_key_dns = 1;
892 warn_changed_key(host_key);
893 error("Update the SSHFP RR in DNS with the new "
894 "host key to get rid of this message.");
899 /* return ok if the key can be found in an old keyfile */
900 if (stat(options.system_hostfile2, &st) == 0 ||
901 stat(options.user_hostfile2, &st) == 0) {
902 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
903 options.user_hostfile2, options.system_hostfile2) == 0)
906 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
907 options.user_hostfile, options.system_hostfile);
911 * Starts a dialog with the server, and authenticates the current user on the
912 * server. This does not need any extra privileges. The basic connection
913 * to the server must already have been established before this is called.
914 * If login fails, this function prints an error and never returns.
915 * This function does not require super-user privileges.
918 ssh_login(Sensitive *sensitive, const char *orighost,
919 struct sockaddr *hostaddr, struct passwd *pw)
922 char *server_user, *local_user;
924 local_user = xstrdup(pw->pw_name);
925 server_user = options.user ? options.user : local_user;
927 /* Convert the user-supplied hostname into all lowercase. */
928 host = xstrdup(orighost);
929 for (cp = host; *cp; cp++)
933 /* Exchange protocol version identification strings with the server. */
934 ssh_exchange_identification();
936 /* Put the connection into non-blocking mode. */
937 packet_set_nonblocking();
940 /* authenticate user */
942 ssh_kex2(host, hostaddr);
943 ssh_userauth2(local_user, server_user, host, sensitive);
945 ssh_kex(host, hostaddr);
946 ssh_userauth1(local_user, server_user, host, sensitive);
951 ssh_put_password(char *password)
956 if (datafellows & SSH_BUG_PASSWORDPAD) {
957 packet_put_cstring(password);
960 size = roundup(strlen(password) + 1, 32);
961 padded = xmalloc(size);
962 memset(padded, 0, size);
963 strlcpy(padded, password, size);
964 packet_put_string(padded, size);
965 memset(padded, 0, size);
970 show_key_from_file(const char *file, const char *host, int keytype)
976 found = key_new(keytype);
977 if ((ret = lookup_key_in_hostfile_by_type(file, host,
978 keytype, found, &line))) {
979 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
980 logit("WARNING: %s key found for host %s\n"
982 "%s key fingerprint %s.",
983 key_type(found), host, file, line,
984 key_type(found), fp);
991 /* print all known host keys for a given host, but skip keys of given type */
993 show_other_keys(const char *host, Key *key)
995 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
998 for (i = 0; type[i] != -1; i++) {
999 if (type[i] == key->type)
1001 if (type[i] != KEY_RSA1 &&
1002 show_key_from_file(options.user_hostfile2, host, type[i])) {
1006 if (type[i] != KEY_RSA1 &&
1007 show_key_from_file(options.system_hostfile2, host, type[i])) {
1011 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1015 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1019 debug2("no key of type %d for host %s", type[i], host);
1025 warn_changed_key(Key *host_key)
1028 const char *type = key_type(host_key);
1030 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1032 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1033 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1034 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1035 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1036 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1037 error("It is also possible that the %s host key has just been changed.", type);
1038 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1040 error("Please contact your system administrator.");
1046 * Execute a local command
1049 ssh_local_cmd(const char *args)
1055 if (!options.permit_local_command ||
1056 args == NULL || !*args)
1059 if ((shell = getenv("SHELL")) == NULL)
1060 shell = _PATH_BSHELL;
1064 debug3("Executing %s -c \"%s\"", shell, args);
1065 execl(shell, shell, "-c", args, (char *)NULL);
1066 error("Couldn't execute %s -c \"%s\": %s",
1067 shell, args, strerror(errno));
1069 } else if (pid == -1)
1070 fatal("fork failed: %.100s", strerror(errno));
1071 while (waitpid(pid, &status, 0) == -1)
1073 fatal("Couldn't wait for child: %s", strerror(errno));
1075 if (!WIFEXITED(status))
1078 return (WEXITSTATUS(status));