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 1.156 2004/01/25 03:49:09 djm Exp $");
18 #include <openssl/bn.h>
28 #include "sshconnect.h"
38 char *client_version_string = NULL;
39 char *server_version_string = NULL;
41 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)
68 char strport[NI_MAXSERV];
70 /* Convert the port number into a string. */
71 snprintf(strport, sizeof strport, "%hu", port);
74 * Build the final command string in the buffer by making the
75 * appropriate substitutions to the given proxy command.
77 * Use "exec" to avoid "sh -c" processes on some platforms
80 buffer_init(&command);
81 buffer_append(&command, "exec ", 5);
83 for (cp = proxy_command; *cp; cp++) {
84 if (cp[0] == '%' && cp[1] == '%') {
85 buffer_append(&command, "%", 1);
89 if (cp[0] == '%' && cp[1] == 'h') {
90 buffer_append(&command, host, strlen(host));
94 if (cp[0] == '%' && cp[1] == 'p') {
95 buffer_append(&command, strport, strlen(strport));
99 buffer_append(&command, cp, 1);
101 buffer_append(&command, "\0", 1);
103 /* Get the final command string. */
104 command_string = buffer_ptr(&command);
106 /* Create pipes for communicating with the proxy. */
107 if (pipe(pin) < 0 || pipe(pout) < 0)
108 fatal("Could not create pipes to communicate with the proxy: %.100s",
111 debug("Executing proxy command: %.500s", command_string);
113 /* Fork and execute the proxy command. */
114 if ((pid = fork()) == 0) {
117 /* Child. Permanently give up superuser privileges. */
118 seteuid(original_real_uid);
119 setuid(original_real_uid);
121 /* Redirect stdin and stdout. */
124 if (dup2(pin[0], 0) < 0)
125 perror("dup2 stdin");
129 if (dup2(pout[1], 1) < 0)
130 perror("dup2 stdout");
131 /* Cannot be 1 because pin allocated two descriptors. */
134 /* Stderr is left as it is so that error messages get
135 printed on the user's terminal. */
136 argv[0] = _PATH_BSHELL;
138 argv[2] = command_string;
141 /* Execute the proxy command. Note that we gave up any
142 extra privileges above. */
143 execv(argv[0], argv);
149 fatal("fork failed: %.100s", strerror(errno));
151 proxy_command_pid = pid; /* save pid to clean up later */
153 /* Close child side of the descriptors. */
157 /* Free the command name. */
158 buffer_free(&command);
160 /* Set the connection file descriptors. */
161 packet_set_connection(pout[0], pin[1]);
163 /* Indicate OK return */
168 * Creates a (possibly privileged) socket for use as the ssh connection.
171 ssh_create_socket(int privileged, struct addrinfo *ai)
174 struct addrinfo hints, *res;
177 * If we are running as root and want to connect to a privileged
178 * port, bind our own socket to a privileged port.
181 int p = IPPORT_RESERVED - 1;
183 sock = rresvport_af(&p, ai->ai_family);
186 error("rresvport: af=%d %.100s", ai->ai_family,
189 debug("Allocated local port %d.", p);
192 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
194 error("socket: %.100s", strerror(errno));
196 /* Bind the socket to an alternative local IP address */
197 if (options.bind_address == NULL)
200 memset(&hints, 0, sizeof(hints));
201 hints.ai_family = ai->ai_family;
202 hints.ai_socktype = ai->ai_socktype;
203 hints.ai_protocol = ai->ai_protocol;
204 hints.ai_flags = AI_PASSIVE;
205 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
207 error("getaddrinfo: %s: %s", options.bind_address,
208 gai_strerror(gaierr));
212 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
213 error("bind: %s: %s", options.bind_address, strerror(errno));
223 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
224 socklen_t addrlen, int timeout)
229 int fdsetsz, optval, rc, result = -1;
232 return (connect(sockfd, serv_addr, addrlen));
234 set_nonblock(sockfd);
235 rc = connect(sockfd, serv_addr, addrlen);
237 unset_nonblock(sockfd);
240 if (errno != EINPROGRESS)
243 fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
244 fdset = (fd_set *)xmalloc(fdsetsz);
246 memset(fdset, 0, fdsetsz);
247 FD_SET(sockfd, fdset);
252 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
253 if (rc != -1 || errno != EINTR)
264 debug("select: %s", strerror(errno));
267 /* Completed or failed */
269 optlen = sizeof(optval);
270 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
272 debug("getsockopt: %s", strerror(errno));
280 unset_nonblock(sockfd);
283 /* Should not occur */
284 fatal("Bogus return (%d) from select()", rc);
292 * Opens a TCP/IP connection to the remote server on the given host.
293 * The address of the remote host will be returned in hostaddr.
294 * If port is 0, the default port will be used. If needpriv is true,
295 * a privileged port will be allocated to make the connection.
296 * This requires super-user privileges if needpriv is true.
297 * Connection_attempts specifies the maximum number of tries (one per
298 * second). If proxy_command is non-NULL, it specifies the command (with %h
299 * and %p substituted for host and port, respectively) to use to contact
303 * ECONNREFUSED if we got a "Connection Refused" by the peer on any address
304 * ECONNABORTED if we failed without a "Connection refused"
305 * Suitable error messages for the connection failure will already have been
309 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
310 u_short port, int family, int connection_attempts,
311 int needpriv, const char *proxy_command)
315 int sock = -1, attempt;
316 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
317 struct addrinfo hints, *ai, *aitop;
320 * Did we get only other errors than "Connection refused" (which
321 * should block fallback to rsh and similar), or did we get at least
322 * one "Connection refused"?
324 int full_failure = 1;
326 debug2("ssh_connect: needpriv %d", needpriv);
328 /* Get default port if port has not been set. */
330 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
332 port = ntohs(sp->s_port);
334 port = SSH_DEFAULT_PORT;
336 /* If a proxy command is given, connect using it. */
337 if (proxy_command != NULL)
338 return ssh_proxy_connect(host, port, proxy_command);
340 /* No proxy command. */
342 memset(&hints, 0, sizeof(hints));
343 hints.ai_family = family;
344 hints.ai_socktype = SOCK_STREAM;
345 snprintf(strport, sizeof strport, "%u", port);
346 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
347 fatal("%s: %.100s: %s", __progname, host,
348 gai_strerror(gaierr));
351 * Try to connect several times. On some machines, the first time
352 * will sometimes fail. In general socket code appears to behave
353 * quite magically on many machines.
355 for (attempt = 0; ;) {
357 debug("Trying again...");
359 /* Loop through addresses for this host, and try each one in
360 sequence until the connection succeeds. */
361 for (ai = aitop; ai; ai = ai->ai_next) {
362 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
364 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
365 ntop, sizeof(ntop), strport, sizeof(strport),
366 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
367 error("ssh_connect: getnameinfo failed");
370 debug("Connecting to %.200s [%.100s] port %s.",
371 host, ntop, strport);
373 /* Create a socket for connecting. */
374 sock = ssh_create_socket(needpriv, ai);
376 /* Any error is already output */
379 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
380 options.connection_timeout) >= 0) {
381 /* Successful connection. */
382 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
385 if (errno == ECONNREFUSED)
387 debug("connect to address %s port %s: %s",
388 ntop, strport, strerror(errno));
390 * Close the failed socket; there appear to
391 * be some problems when reusing a socket for
392 * which connect() has already returned an
399 break; /* Successful connection. */
402 if (attempt >= connection_attempts)
404 /* Sleep a moment before retrying. */
410 /* Return failure if we didn't get a successful connection. */
411 if (attempt >= connection_attempts) {
412 logit("ssh: connect to host %s port %s: %s",
413 host, strport, strerror(errno));
414 return full_failure ? ECONNABORTED : ECONNREFUSED;
417 debug("Connection established.");
419 /* Set SO_KEEPALIVE if requested. */
420 if (options.tcp_keep_alive &&
421 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
423 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
425 /* Set the connection. */
426 packet_set_connection(sock, sock);
432 * Waits for the server identification string, and sends our own
433 * identification string.
436 ssh_exchange_identification(void)
438 char buf[256], remote_version[256]; /* must be same size! */
439 int remote_major, remote_minor, i, mismatch;
440 int connection_in = packet_get_connection_in();
441 int connection_out = packet_get_connection_out();
442 int minor1 = PROTOCOL_MINOR_1;
444 /* Read other side\'s version identification. */
446 for (i = 0; i < sizeof(buf) - 1; i++) {
447 int len = atomicio(read, connection_in, &buf[i], 1);
449 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
451 fatal("ssh_exchange_identification: Connection closed by remote host");
452 if (buf[i] == '\r') {
455 continue; /**XXX wait for \n */
457 if (buf[i] == '\n') {
462 buf[sizeof(buf) - 1] = 0;
463 if (strncmp(buf, "SSH-", 4) == 0)
465 debug("ssh_exchange_identification: %s", buf);
467 server_version_string = xstrdup(buf);
470 * Check that the versions match. In future this might accept
471 * several versions and set appropriate flags to handle them.
473 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
474 &remote_major, &remote_minor, remote_version) != 3)
475 fatal("Bad remote protocol version identification: '%.100s'", buf);
476 debug("Remote protocol version %d.%d, remote software version %.100s",
477 remote_major, remote_minor, remote_version);
479 compat_datafellows(remote_version);
482 switch (remote_major) {
484 if (remote_minor == 99 &&
485 (options.protocol & SSH_PROTO_2) &&
486 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
490 if (!(options.protocol & SSH_PROTO_1)) {
494 if (remote_minor < 3) {
495 fatal("Remote machine has too old SSH software version.");
496 } else if (remote_minor == 3 || remote_minor == 4) {
497 /* We speak 1.3, too. */
500 if (options.forward_agent) {
501 logit("Agent forwarding disabled for protocol 1.3");
502 options.forward_agent = 0;
507 if (options.protocol & SSH_PROTO_2) {
517 fatal("Protocol major versions differ: %d vs. %d",
518 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
520 /* Send our own protocol version identification. */
521 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
522 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
523 compat20 ? PROTOCOL_MINOR_2 : minor1,
525 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
526 fatal("write: %.100s", strerror(errno));
527 client_version_string = xstrdup(buf);
528 chop(client_version_string);
529 chop(server_version_string);
530 debug("Local version string %.100s", client_version_string);
533 /* defaults to 'no' */
535 confirm(const char *prompt)
537 const char *msg, *again = "Please type 'yes' or 'no': ";
541 if (options.batch_mode)
543 for (msg = prompt;;msg = again) {
544 p = read_passphrase(msg, RP_ECHO);
546 (p[0] == '\0') || (p[0] == '\n') ||
547 strncasecmp(p, "no", 2) == 0)
549 if (p && strncasecmp(p, "yes", 3) == 0)
559 * check whether the supplied host key is valid, return -1 if the key
560 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
563 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
564 int readonly, const char *user_hostfile, const char *system_hostfile)
567 const char *type = key_type(host_key);
569 char hostline[1000], *hostp, *fp;
570 HostStatus host_status;
571 HostStatus ip_status;
572 int local = 0, host_ip_differ = 0;
574 char ntop[NI_MAXHOST];
576 int len, host_line, ip_line;
577 const char *host_file = NULL, *ip_file = NULL;
580 * Force accepting of the host key for loopback/localhost. The
581 * problem is that if the home directory is NFS-mounted to multiple
582 * machines, localhost will refer to a different machine in each of
583 * them, and the user will get bogus HOST_CHANGED warnings. This
584 * essentially disables host authentication for localhost; however,
585 * this is probably not a real problem.
587 /** hostaddr == 0! */
588 switch (hostaddr->sa_family) {
590 local = (ntohl(((struct sockaddr_in *)hostaddr)->
591 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
592 salen = sizeof(struct sockaddr_in);
595 local = IN6_IS_ADDR_LOOPBACK(
596 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
597 salen = sizeof(struct sockaddr_in6);
601 salen = sizeof(struct sockaddr_storage);
604 if (options.no_host_authentication_for_localhost == 1 && local &&
605 options.host_key_alias == NULL) {
606 debug("Forcing accepting of host key for "
607 "loopback/localhost.");
612 * We don't have the remote ip-address for connections
613 * using a proxy command
615 if (options.proxy_command == NULL) {
616 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
617 NULL, 0, NI_NUMERICHOST) != 0)
618 fatal("check_host_key: getnameinfo failed");
621 ip = xstrdup("<no hostip for proxy command>");
624 * Turn off check_host_ip if the connection is to localhost, via proxy
625 * command or if we don't have a hostname to compare with
627 if (options.check_host_ip &&
628 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
629 options.check_host_ip = 0;
632 * Allow the user to record the key under a different name. This is
633 * useful for ssh tunneling over forwarded connections or if you run
634 * multiple sshd's on different ports on the same machine.
636 if (options.host_key_alias != NULL) {
637 host = options.host_key_alias;
638 debug("using hostkeyalias: %s", host);
642 * Store the host key from the known host file in here so that we can
643 * compare it with the key for the IP address.
645 file_key = key_new(host_key->type);
648 * Check if the host key is present in the user\'s list of known
649 * hosts or in the systemwide list.
651 host_file = user_hostfile;
652 host_status = check_host_in_hostfile(host_file, host, host_key,
653 file_key, &host_line);
654 if (host_status == HOST_NEW) {
655 host_file = system_hostfile;
656 host_status = check_host_in_hostfile(host_file, host, host_key,
657 file_key, &host_line);
660 * Also perform check for the ip address, skip the check if we are
661 * localhost or the hostname was an ip address to begin with
663 if (options.check_host_ip) {
664 Key *ip_key = key_new(host_key->type);
666 ip_file = user_hostfile;
667 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
669 if (ip_status == HOST_NEW) {
670 ip_file = system_hostfile;
671 ip_status = check_host_in_hostfile(ip_file, ip,
672 host_key, ip_key, &ip_line);
674 if (host_status == HOST_CHANGED &&
675 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
680 ip_status = host_status;
684 switch (host_status) {
686 /* The host is known and the key matches. */
687 debug("Host '%.200s' is known and matches the %s host key.",
689 debug("Found key in %s:%d", host_file, host_line);
690 if (options.check_host_ip && ip_status == HOST_NEW) {
692 logit("%s host key for IP address "
693 "'%.128s' not in list of known hosts.",
695 else if (!add_host_to_hostfile(user_hostfile, ip,
697 logit("Failed to add the %s host key for IP "
698 "address '%.128s' to the list of known "
699 "hosts (%.30s).", type, ip, user_hostfile);
701 logit("Warning: Permanently added the %s host "
702 "key for IP address '%.128s' to the list "
703 "of known hosts.", type, ip);
709 /* The host is new. */
710 if (options.strict_host_key_checking == 1) {
712 * User has requested strict host key checking. We
713 * will not add the host key automatically. The only
714 * alternative left is to abort.
716 error("No %s host key is known for %.200s and you "
717 "have requested strict checking.", type, host);
719 } else if (options.strict_host_key_checking == 2) {
720 char msg1[1024], msg2[1024];
722 if (show_other_keys(host, host_key))
723 snprintf(msg1, sizeof(msg1),
724 "\nbut keys of different type are already"
725 " known for this host.");
727 snprintf(msg1, sizeof(msg1), ".");
729 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
731 if (options.verify_host_key_dns) {
732 if (matching_host_key_dns)
733 snprintf(msg2, sizeof(msg2),
734 "Matching host key fingerprint"
737 snprintf(msg2, sizeof(msg2),
738 "No matching host key fingerprint"
741 snprintf(msg, sizeof(msg),
742 "The authenticity of host '%.200s (%s)' can't be "
744 "%s key fingerprint is %s.\n%s"
745 "Are you sure you want to continue connecting "
747 host, ip, msg1, type, fp, msg2);
752 if (options.check_host_ip && ip_status == HOST_NEW) {
753 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
759 * If not in strict mode, add the key automatically to the
760 * local known_hosts file.
762 if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
763 logit("Failed to add the host to the list of known "
764 "hosts (%.500s).", user_hostfile);
766 logit("Warning: Permanently added '%.200s' (%s) to the "
767 "list of known hosts.", hostp, type);
770 if (options.check_host_ip && host_ip_differ) {
772 if (ip_status == HOST_NEW)
774 else if (ip_status == HOST_OK)
775 msg = "is unchanged";
777 msg = "has a different value";
778 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
779 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
780 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
781 error("The %s host key for %s has changed,", type, host);
782 error("and the key for the according IP address %s", ip);
783 error("%s. This could either mean that", msg);
784 error("DNS SPOOFING is happening or the IP address for the host");
785 error("and its host key have changed at the same time.");
786 if (ip_status != HOST_NEW)
787 error("Offending key for IP in %s:%d", ip_file, ip_line);
789 /* The host key has changed. */
790 warn_changed_key(host_key);
791 error("Add correct host key in %.100s to get rid of this message.",
793 error("Offending key in %s:%d", host_file, host_line);
796 * If strict host key checking is in use, the user will have
797 * to edit the key manually and we can only abort.
799 if (options.strict_host_key_checking) {
800 error("%s host key for %.200s has changed and you have "
801 "requested strict checking.", type, host);
806 * If strict host key checking has not been requested, allow
807 * the connection but without MITM-able authentication or
810 if (options.password_authentication) {
811 error("Password authentication is disabled to avoid "
812 "man-in-the-middle attacks.");
813 options.password_authentication = 0;
815 if (options.kbd_interactive_authentication) {
816 error("Keyboard-interactive authentication is disabled"
817 " to avoid man-in-the-middle attacks.");
818 options.kbd_interactive_authentication = 0;
819 options.challenge_response_authentication = 0;
821 if (options.challenge_response_authentication) {
822 error("Challenge/response authentication is disabled"
823 " to avoid man-in-the-middle attacks.");
824 options.challenge_response_authentication = 0;
826 if (options.forward_agent) {
827 error("Agent forwarding is disabled to avoid "
828 "man-in-the-middle attacks.");
829 options.forward_agent = 0;
831 if (options.forward_x11) {
832 error("X11 forwarding is disabled to avoid "
833 "man-in-the-middle attacks.");
834 options.forward_x11 = 0;
836 if (options.num_local_forwards > 0 ||
837 options.num_remote_forwards > 0) {
838 error("Port forwarding is disabled to avoid "
839 "man-in-the-middle attacks.");
840 options.num_local_forwards =
841 options.num_remote_forwards = 0;
844 * XXX Should permit the user to change to use the new id.
845 * This could be done by converting the host key to an
846 * identifying sentence, tell that the host identifies itself
847 * by that sentence, and ask the user if he/she whishes to
848 * accept the authentication.
852 fatal("internal error");
856 if (options.check_host_ip && host_status != HOST_CHANGED &&
857 ip_status == HOST_CHANGED) {
858 snprintf(msg, sizeof(msg),
859 "Warning: the %s host key for '%.200s' "
860 "differs from the key for the IP address '%.128s'"
861 "\nOffending key for IP in %s:%d",
862 type, host, ip, ip_file, ip_line);
863 if (host_status == HOST_OK) {
865 snprintf(msg + len, sizeof(msg) - len,
866 "\nMatching host key in %s:%d",
867 host_file, host_line);
869 if (options.strict_host_key_checking == 1) {
871 error("Exiting, you have requested strict checking.");
873 } else if (options.strict_host_key_checking == 2) {
874 strlcat(msg, "\nAre you sure you want "
875 "to continue connecting (yes/no)? ", sizeof(msg));
891 /* returns 0 if key verifies or -1 if key does NOT verify */
893 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
898 if (options.verify_host_key_dns &&
899 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
901 if (flags & DNS_VERIFY_FOUND) {
903 if (options.verify_host_key_dns == 1 &&
904 flags & DNS_VERIFY_MATCH &&
905 flags & DNS_VERIFY_SECURE)
908 if (flags & DNS_VERIFY_MATCH) {
909 matching_host_key_dns = 1;
911 warn_changed_key(host_key);
912 error("Update the SSHFP RR in DNS with the new "
913 "host key to get rid of this message.");
918 /* return ok if the key can be found in an old keyfile */
919 if (stat(options.system_hostfile2, &st) == 0 ||
920 stat(options.user_hostfile2, &st) == 0) {
921 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
922 options.user_hostfile2, options.system_hostfile2) == 0)
925 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
926 options.user_hostfile, options.system_hostfile);
930 * Starts a dialog with the server, and authenticates the current user on the
931 * server. This does not need any extra privileges. The basic connection
932 * to the server must already have been established before this is called.
933 * If login fails, this function prints an error and never returns.
934 * This function does not require super-user privileges.
937 ssh_login(Sensitive *sensitive, const char *orighost,
938 struct sockaddr *hostaddr, struct passwd *pw)
941 char *server_user, *local_user;
943 local_user = xstrdup(pw->pw_name);
944 server_user = options.user ? options.user : local_user;
946 /* Convert the user-supplied hostname into all lowercase. */
947 host = xstrdup(orighost);
948 for (cp = host; *cp; cp++)
952 /* Exchange protocol version identification strings with the server. */
953 ssh_exchange_identification();
955 /* Put the connection into non-blocking mode. */
956 packet_set_nonblocking();
959 /* authenticate user */
961 ssh_kex2(host, hostaddr);
962 ssh_userauth2(local_user, server_user, host, sensitive);
964 ssh_kex(host, hostaddr);
965 ssh_userauth1(local_user, server_user, host, sensitive);
970 ssh_put_password(char *password)
975 if (datafellows & SSH_BUG_PASSWORDPAD) {
976 packet_put_cstring(password);
979 size = roundup(strlen(password) + 1, 32);
980 padded = xmalloc(size);
981 memset(padded, 0, size);
982 strlcpy(padded, password, size);
983 packet_put_string(padded, size);
984 memset(padded, 0, size);
989 show_key_from_file(const char *file, const char *host, int keytype)
995 found = key_new(keytype);
996 if ((ret = lookup_key_in_hostfile_by_type(file, host,
997 keytype, found, &line))) {
998 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
999 logit("WARNING: %s key found for host %s\n"
1001 "%s key fingerprint %s.",
1002 key_type(found), host, file, line,
1003 key_type(found), fp);
1010 /* print all known host keys for a given host, but skip keys of given type */
1012 show_other_keys(const char *host, Key *key)
1014 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1017 for (i = 0; type[i] != -1; i++) {
1018 if (type[i] == key->type)
1020 if (type[i] != KEY_RSA1 &&
1021 show_key_from_file(options.user_hostfile2, host, type[i])) {
1025 if (type[i] != KEY_RSA1 &&
1026 show_key_from_file(options.system_hostfile2, host, type[i])) {
1030 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1034 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1038 debug2("no key of type %d for host %s", type[i], host);
1044 warn_changed_key(Key *host_key)
1047 const char *type = key_type(host_key);
1049 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1051 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1052 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1053 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1054 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1055 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1056 error("It is also possible that the %s host key has just been changed.", type);
1057 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1059 error("Please contact your system administrator.");