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 1.163 2005/05/24 17:32:44 avsm Exp $");
18 #include <openssl/bn.h>
28 #include "sshconnect.h"
37 char *client_version_string = NULL;
38 char *server_version_string = NULL;
40 int matching_host_key_dns = 0;
43 extern Options options;
44 extern char *__progname;
45 extern uid_t original_real_uid;
46 extern uid_t original_effective_uid;
47 extern pid_t proxy_command_pid;
49 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
50 #define INET6_ADDRSTRLEN 46
53 static int show_other_keys(const char *, Key *);
54 static void warn_changed_key(Key *);
57 * Connect to the given ssh server using a proxy command.
60 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
67 char strport[NI_MAXSERV];
69 /* Convert the port number into a string. */
70 snprintf(strport, sizeof strport, "%hu", port);
73 * Build the final command string in the buffer by making the
74 * appropriate substitutions to the given proxy command.
76 * Use "exec" to avoid "sh -c" processes on some platforms
79 buffer_init(&command);
80 buffer_append(&command, "exec ", 5);
82 for (cp = proxy_command; *cp; cp++) {
83 if (cp[0] == '%' && cp[1] == '%') {
84 buffer_append(&command, "%", 1);
88 if (cp[0] == '%' && cp[1] == 'h') {
89 buffer_append(&command, host, strlen(host));
93 if (cp[0] == '%' && cp[1] == 'p') {
94 buffer_append(&command, strport, strlen(strport));
98 buffer_append(&command, cp, 1);
100 buffer_append(&command, "\0", 1);
102 /* Get the final command string. */
103 command_string = buffer_ptr(&command);
105 /* Create pipes for communicating with the proxy. */
106 if (pipe(pin) < 0 || pipe(pout) < 0)
107 fatal("Could not create pipes to communicate with the proxy: %.100s",
110 debug("Executing proxy command: %.500s", command_string);
112 /* Fork and execute the proxy command. */
113 if ((pid = fork()) == 0) {
116 /* Child. Permanently give up superuser privileges. */
117 seteuid(original_real_uid);
118 setuid(original_real_uid);
120 /* Redirect stdin and stdout. */
123 if (dup2(pin[0], 0) < 0)
124 perror("dup2 stdin");
128 if (dup2(pout[1], 1) < 0)
129 perror("dup2 stdout");
130 /* Cannot be 1 because pin allocated two descriptors. */
133 /* Stderr is left as it is so that error messages get
134 printed on the user's terminal. */
135 argv[0] = _PATH_BSHELL;
137 argv[2] = command_string;
140 /* Execute the proxy command. Note that we gave up any
141 extra privileges above. */
142 execv(argv[0], argv);
148 fatal("fork failed: %.100s", strerror(errno));
150 proxy_command_pid = pid; /* save pid to clean up later */
152 /* Close child side of the descriptors. */
156 /* Free the command name. */
157 buffer_free(&command);
159 /* Set the connection file descriptors. */
160 packet_set_connection(pout[0], pin[1]);
162 /* Indicate OK return */
167 * Creates a (possibly privileged) socket for use as the ssh connection.
170 ssh_create_socket(int privileged, struct addrinfo *ai)
173 struct addrinfo hints, *res;
176 * If we are running as root and want to connect to a privileged
177 * port, bind our own socket to a privileged port.
180 int p = IPPORT_RESERVED - 1;
182 sock = rresvport_af(&p, ai->ai_family);
185 error("rresvport: af=%d %.100s", ai->ai_family,
188 debug("Allocated local port %d.", p);
191 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
193 error("socket: %.100s", strerror(errno));
195 /* Bind the socket to an alternative local IP address */
196 if (options.bind_address == NULL)
199 memset(&hints, 0, sizeof(hints));
200 hints.ai_family = ai->ai_family;
201 hints.ai_socktype = ai->ai_socktype;
202 hints.ai_protocol = ai->ai_protocol;
203 hints.ai_flags = AI_PASSIVE;
204 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
206 error("getaddrinfo: %s: %s", options.bind_address,
207 gai_strerror(gaierr));
211 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
212 error("bind: %s: %s", options.bind_address, strerror(errno));
222 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
223 socklen_t addrlen, int timeout)
228 int fdsetsz, optval, rc, result = -1;
231 return (connect(sockfd, serv_addr, addrlen));
233 set_nonblock(sockfd);
234 rc = connect(sockfd, serv_addr, addrlen);
236 unset_nonblock(sockfd);
239 if (errno != EINPROGRESS)
242 fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
243 fdset = (fd_set *)xmalloc(fdsetsz);
245 memset(fdset, 0, fdsetsz);
246 FD_SET(sockfd, fdset);
251 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
252 if (rc != -1 || errno != EINTR)
263 debug("select: %s", strerror(errno));
266 /* Completed or failed */
268 optlen = sizeof(optval);
269 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
271 debug("getsockopt: %s", strerror(errno));
279 unset_nonblock(sockfd);
282 /* Should not occur */
283 fatal("Bogus return (%d) from select()", rc);
291 * Opens a TCP/IP connection to the remote server on the given host.
292 * The address of the remote host will be returned in hostaddr.
293 * If port is 0, the default port will be used. If needpriv is true,
294 * a privileged port will be allocated to make the connection.
295 * This requires super-user privileges if needpriv is true.
296 * Connection_attempts specifies the maximum number of tries (one per
297 * second). If proxy_command is non-NULL, it specifies the command (with %h
298 * and %p substituted for host and port, respectively) to use to contact
302 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
303 u_short port, int family, int connection_attempts,
304 int needpriv, const char *proxy_command)
308 int sock = -1, attempt;
309 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
310 struct addrinfo hints, *ai, *aitop;
313 debug2("ssh_connect: needpriv %d", needpriv);
315 /* Get default port if port has not been set. */
317 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
319 port = ntohs(sp->s_port);
321 port = SSH_DEFAULT_PORT;
323 /* If a proxy command is given, connect using it. */
324 if (proxy_command != NULL)
325 return ssh_proxy_connect(host, port, proxy_command);
327 /* No proxy command. */
329 memset(&hints, 0, sizeof(hints));
330 hints.ai_family = family;
331 hints.ai_socktype = SOCK_STREAM;
332 snprintf(strport, sizeof strport, "%u", port);
333 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
334 fatal("%s: %.100s: %s", __progname, host,
335 gai_strerror(gaierr));
338 * Try to connect several times. On some machines, the first time
339 * will sometimes fail. In general socket code appears to behave
340 * quite magically on many machines.
342 for (attempt = 0; ;) {
344 debug("Trying again...");
346 /* Loop through addresses for this host, and try each one in
347 sequence until the connection succeeds. */
348 for (ai = aitop; ai; ai = ai->ai_next) {
349 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
351 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
352 ntop, sizeof(ntop), strport, sizeof(strport),
353 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
354 error("ssh_connect: getnameinfo failed");
357 debug("Connecting to %.200s [%.100s] port %s.",
358 host, ntop, strport);
360 /* Create a socket for connecting. */
361 sock = ssh_create_socket(needpriv, ai);
363 /* Any error is already output */
366 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
367 options.connection_timeout) >= 0) {
368 /* Successful connection. */
369 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
372 debug("connect to address %s port %s: %s",
373 ntop, strport, strerror(errno));
375 * Close the failed socket; there appear to
376 * be some problems when reusing a socket for
377 * which connect() has already returned an
384 break; /* Successful connection. */
387 if (attempt >= connection_attempts)
389 /* Sleep a moment before retrying. */
395 /* Return failure if we didn't get a successful connection. */
396 if (attempt >= connection_attempts) {
397 error("ssh: connect to host %s port %s: %s",
398 host, strport, strerror(errno));
402 debug("Connection established.");
404 /* Set SO_KEEPALIVE if requested. */
405 if (options.tcp_keep_alive &&
406 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
408 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
410 /* Set the connection. */
411 packet_set_connection(sock, sock);
417 * Waits for the server identification string, and sends our own
418 * identification string.
421 ssh_exchange_identification(void)
423 char buf[256], remote_version[256]; /* must be same size! */
424 int remote_major, remote_minor, i, mismatch;
425 int connection_in = packet_get_connection_in();
426 int connection_out = packet_get_connection_out();
427 int minor1 = PROTOCOL_MINOR_1;
429 /* Read other side's version identification. */
431 for (i = 0; i < sizeof(buf) - 1; i++) {
432 size_t len = atomicio(read, connection_in, &buf[i], 1);
434 if (len != 1 && errno == EPIPE)
435 fatal("ssh_exchange_identification: Connection closed by remote host");
437 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
438 if (buf[i] == '\r') {
441 continue; /**XXX wait for \n */
443 if (buf[i] == '\n') {
448 buf[sizeof(buf) - 1] = 0;
449 if (strncmp(buf, "SSH-", 4) == 0)
451 debug("ssh_exchange_identification: %s", buf);
453 server_version_string = xstrdup(buf);
456 * Check that the versions match. In future this might accept
457 * several versions and set appropriate flags to handle them.
459 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
460 &remote_major, &remote_minor, remote_version) != 3)
461 fatal("Bad remote protocol version identification: '%.100s'", buf);
462 debug("Remote protocol version %d.%d, remote software version %.100s",
463 remote_major, remote_minor, remote_version);
465 compat_datafellows(remote_version);
468 switch (remote_major) {
470 if (remote_minor == 99 &&
471 (options.protocol & SSH_PROTO_2) &&
472 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
476 if (!(options.protocol & SSH_PROTO_1)) {
480 if (remote_minor < 3) {
481 fatal("Remote machine has too old SSH software version.");
482 } else if (remote_minor == 3 || remote_minor == 4) {
483 /* We speak 1.3, too. */
486 if (options.forward_agent) {
487 logit("Agent forwarding disabled for protocol 1.3");
488 options.forward_agent = 0;
493 if (options.protocol & SSH_PROTO_2) {
503 fatal("Protocol major versions differ: %d vs. %d",
504 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
506 /* Send our own protocol version identification. */
507 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
508 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
509 compat20 ? PROTOCOL_MINOR_2 : minor1,
511 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
512 fatal("write: %.100s", strerror(errno));
513 client_version_string = xstrdup(buf);
514 chop(client_version_string);
515 chop(server_version_string);
516 debug("Local version string %.100s", client_version_string);
519 /* defaults to 'no' */
521 confirm(const char *prompt)
523 const char *msg, *again = "Please type 'yes' or 'no': ";
527 if (options.batch_mode)
529 for (msg = prompt;;msg = again) {
530 p = read_passphrase(msg, RP_ECHO);
532 (p[0] == '\0') || (p[0] == '\n') ||
533 strncasecmp(p, "no", 2) == 0)
535 if (p && strncasecmp(p, "yes", 3) == 0)
545 * check whether the supplied host key is valid, return -1 if the key
546 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
549 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
550 int readonly, const char *user_hostfile, const char *system_hostfile)
553 const char *type = key_type(host_key);
555 char hostline[1000], *hostp, *fp;
556 HostStatus host_status;
557 HostStatus ip_status;
558 int r, local = 0, host_ip_differ = 0;
560 char ntop[NI_MAXHOST];
562 int len, host_line, ip_line;
563 const char *host_file = NULL, *ip_file = NULL;
566 * Force accepting of the host key for loopback/localhost. The
567 * problem is that if the home directory is NFS-mounted to multiple
568 * machines, localhost will refer to a different machine in each of
569 * them, and the user will get bogus HOST_CHANGED warnings. This
570 * essentially disables host authentication for localhost; however,
571 * this is probably not a real problem.
573 /** hostaddr == 0! */
574 switch (hostaddr->sa_family) {
576 local = (ntohl(((struct sockaddr_in *)hostaddr)->
577 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
578 salen = sizeof(struct sockaddr_in);
581 local = IN6_IS_ADDR_LOOPBACK(
582 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
583 salen = sizeof(struct sockaddr_in6);
587 salen = sizeof(struct sockaddr_storage);
590 if (options.no_host_authentication_for_localhost == 1 && local &&
591 options.host_key_alias == NULL) {
592 debug("Forcing accepting of host key for "
593 "loopback/localhost.");
598 * We don't have the remote ip-address for connections
599 * using a proxy command
601 if (options.proxy_command == NULL) {
602 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
603 NULL, 0, NI_NUMERICHOST) != 0)
604 fatal("check_host_key: getnameinfo failed");
607 ip = xstrdup("<no hostip for proxy command>");
610 * Turn off check_host_ip if the connection is to localhost, via proxy
611 * command or if we don't have a hostname to compare with
613 if (options.check_host_ip &&
614 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
615 options.check_host_ip = 0;
618 * Allow the user to record the key under a different name. This is
619 * useful for ssh tunneling over forwarded connections or if you run
620 * multiple sshd's on different ports on the same machine.
622 if (options.host_key_alias != NULL) {
623 host = options.host_key_alias;
624 debug("using hostkeyalias: %s", host);
628 * Store the host key from the known host file in here so that we can
629 * compare it with the key for the IP address.
631 file_key = key_new(host_key->type);
634 * Check if the host key is present in the user\'s list of known
635 * hosts or in the systemwide list.
637 host_file = user_hostfile;
638 host_status = check_host_in_hostfile(host_file, host, host_key,
639 file_key, &host_line);
640 if (host_status == HOST_NEW) {
641 host_file = system_hostfile;
642 host_status = check_host_in_hostfile(host_file, host, host_key,
643 file_key, &host_line);
646 * Also perform check for the ip address, skip the check if we are
647 * localhost or the hostname was an ip address to begin with
649 if (options.check_host_ip) {
650 Key *ip_key = key_new(host_key->type);
652 ip_file = user_hostfile;
653 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
655 if (ip_status == HOST_NEW) {
656 ip_file = system_hostfile;
657 ip_status = check_host_in_hostfile(ip_file, ip,
658 host_key, ip_key, &ip_line);
660 if (host_status == HOST_CHANGED &&
661 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
666 ip_status = host_status;
670 switch (host_status) {
672 /* The host is known and the key matches. */
673 debug("Host '%.200s' is known and matches the %s host key.",
675 debug("Found key in %s:%d", host_file, host_line);
676 if (options.check_host_ip && ip_status == HOST_NEW) {
678 logit("%s host key for IP address "
679 "'%.128s' not in list of known hosts.",
681 else if (!add_host_to_hostfile(user_hostfile, ip,
682 host_key, options.hash_known_hosts))
683 logit("Failed to add the %s host key for IP "
684 "address '%.128s' to the list of known "
685 "hosts (%.30s).", type, ip, user_hostfile);
687 logit("Warning: Permanently added the %s host "
688 "key for IP address '%.128s' to the list "
689 "of known hosts.", type, ip);
695 /* The host is new. */
696 if (options.strict_host_key_checking == 1) {
698 * User has requested strict host key checking. We
699 * will not add the host key automatically. The only
700 * alternative left is to abort.
702 error("No %s host key is known for %.200s and you "
703 "have requested strict checking.", type, host);
705 } else if (options.strict_host_key_checking == 2) {
706 char msg1[1024], msg2[1024];
708 if (show_other_keys(host, host_key))
709 snprintf(msg1, sizeof(msg1),
710 "\nbut keys of different type are already"
711 " known for this host.");
713 snprintf(msg1, sizeof(msg1), ".");
715 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
717 if (options.verify_host_key_dns) {
718 if (matching_host_key_dns)
719 snprintf(msg2, sizeof(msg2),
720 "Matching host key fingerprint"
723 snprintf(msg2, sizeof(msg2),
724 "No matching host key fingerprint"
727 snprintf(msg, sizeof(msg),
728 "The authenticity of host '%.200s (%s)' can't be "
730 "%s key fingerprint is %s.\n%s"
731 "Are you sure you want to continue connecting "
733 host, ip, msg1, type, fp, msg2);
739 * If not in strict mode, add the key automatically to the
740 * local known_hosts file.
742 if (options.check_host_ip && ip_status == HOST_NEW) {
743 snprintf(hostline, sizeof(hostline), "%s,%s",
746 if (options.hash_known_hosts) {
747 /* Add hash of host and IP separately */
748 r = add_host_to_hostfile(user_hostfile, host,
749 host_key, options.hash_known_hosts) &&
750 add_host_to_hostfile(user_hostfile, ip,
751 host_key, options.hash_known_hosts);
753 /* Add unhashed "host,ip" */
754 r = add_host_to_hostfile(user_hostfile,
756 options.hash_known_hosts);
759 r = add_host_to_hostfile(user_hostfile, host, host_key,
760 options.hash_known_hosts);
765 logit("Failed to add the host to the list of known "
766 "hosts (%.500s).", user_hostfile);
768 logit("Warning: Permanently added '%.200s' (%s) to the "
769 "list of known hosts.", hostp, type);
772 if (options.check_host_ip && host_ip_differ) {
774 if (ip_status == HOST_NEW)
775 key_msg = "is unknown";
776 else if (ip_status == HOST_OK)
777 key_msg = "is unchanged";
779 key_msg = "has a different value";
780 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
781 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
782 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
783 error("The %s host key for %s has changed,", type, host);
784 error("and the key for the according IP address %s", ip);
785 error("%s. This could either mean that", key_msg);
786 error("DNS SPOOFING is happening or the IP address for the host");
787 error("and its host key have changed at the same time.");
788 if (ip_status != HOST_NEW)
789 error("Offending key for IP in %s:%d", ip_file, ip_line);
791 /* The host key has changed. */
792 warn_changed_key(host_key);
793 error("Add correct host key in %.100s to get rid of this message.",
795 error("Offending key in %s:%d", host_file, host_line);
798 * If strict host key checking is in use, the user will have
799 * to edit the key manually and we can only abort.
801 if (options.strict_host_key_checking) {
802 error("%s host key for %.200s has changed and you have "
803 "requested strict checking.", type, host);
808 * If strict host key checking has not been requested, allow
809 * the connection but without MITM-able authentication or
812 if (options.password_authentication) {
813 error("Password authentication is disabled to avoid "
814 "man-in-the-middle attacks.");
815 options.password_authentication = 0;
817 if (options.kbd_interactive_authentication) {
818 error("Keyboard-interactive authentication is disabled"
819 " to avoid man-in-the-middle attacks.");
820 options.kbd_interactive_authentication = 0;
821 options.challenge_response_authentication = 0;
823 if (options.challenge_response_authentication) {
824 error("Challenge/response authentication is disabled"
825 " to avoid man-in-the-middle attacks.");
826 options.challenge_response_authentication = 0;
828 if (options.forward_agent) {
829 error("Agent forwarding is disabled to avoid "
830 "man-in-the-middle attacks.");
831 options.forward_agent = 0;
833 if (options.forward_x11) {
834 error("X11 forwarding is disabled to avoid "
835 "man-in-the-middle attacks.");
836 options.forward_x11 = 0;
838 if (options.num_local_forwards > 0 ||
839 options.num_remote_forwards > 0) {
840 error("Port forwarding is disabled to avoid "
841 "man-in-the-middle attacks.");
842 options.num_local_forwards =
843 options.num_remote_forwards = 0;
846 * XXX Should permit the user to change to use the new id.
847 * This could be done by converting the host key to an
848 * identifying sentence, tell that the host identifies itself
849 * by that sentence, and ask the user if he/she whishes to
850 * accept the authentication.
854 fatal("internal error");
858 if (options.check_host_ip && host_status != HOST_CHANGED &&
859 ip_status == HOST_CHANGED) {
860 snprintf(msg, sizeof(msg),
861 "Warning: the %s host key for '%.200s' "
862 "differs from the key for the IP address '%.128s'"
863 "\nOffending key for IP in %s:%d",
864 type, host, ip, ip_file, ip_line);
865 if (host_status == HOST_OK) {
867 snprintf(msg + len, sizeof(msg) - len,
868 "\nMatching host key in %s:%d",
869 host_file, host_line);
871 if (options.strict_host_key_checking == 1) {
873 error("Exiting, you have requested strict checking.");
875 } else if (options.strict_host_key_checking == 2) {
876 strlcat(msg, "\nAre you sure you want "
877 "to continue connecting (yes/no)? ", sizeof(msg));
893 /* returns 0 if key verifies or -1 if key does NOT verify */
895 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
900 if (options.verify_host_key_dns &&
901 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
903 if (flags & DNS_VERIFY_FOUND) {
905 if (options.verify_host_key_dns == 1 &&
906 flags & DNS_VERIFY_MATCH &&
907 flags & DNS_VERIFY_SECURE)
910 if (flags & DNS_VERIFY_MATCH) {
911 matching_host_key_dns = 1;
913 warn_changed_key(host_key);
914 error("Update the SSHFP RR in DNS with the new "
915 "host key to get rid of this message.");
920 /* return ok if the key can be found in an old keyfile */
921 if (stat(options.system_hostfile2, &st) == 0 ||
922 stat(options.user_hostfile2, &st) == 0) {
923 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
924 options.user_hostfile2, options.system_hostfile2) == 0)
927 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
928 options.user_hostfile, options.system_hostfile);
932 * Starts a dialog with the server, and authenticates the current user on the
933 * server. This does not need any extra privileges. The basic connection
934 * to the server must already have been established before this is called.
935 * If login fails, this function prints an error and never returns.
936 * This function does not require super-user privileges.
939 ssh_login(Sensitive *sensitive, const char *orighost,
940 struct sockaddr *hostaddr, struct passwd *pw)
943 char *server_user, *local_user;
945 local_user = xstrdup(pw->pw_name);
946 server_user = options.user ? options.user : local_user;
948 /* Convert the user-supplied hostname into all lowercase. */
949 host = xstrdup(orighost);
950 for (cp = host; *cp; cp++)
954 /* Exchange protocol version identification strings with the server. */
955 ssh_exchange_identification();
957 /* Put the connection into non-blocking mode. */
958 packet_set_nonblocking();
961 /* authenticate user */
963 ssh_kex2(host, hostaddr);
964 ssh_userauth2(local_user, server_user, host, sensitive);
966 ssh_kex(host, hostaddr);
967 ssh_userauth1(local_user, server_user, host, sensitive);
972 ssh_put_password(char *password)
977 if (datafellows & SSH_BUG_PASSWORDPAD) {
978 packet_put_cstring(password);
981 size = roundup(strlen(password) + 1, 32);
982 padded = xmalloc(size);
983 memset(padded, 0, size);
984 strlcpy(padded, password, size);
985 packet_put_string(padded, size);
986 memset(padded, 0, size);
991 show_key_from_file(const char *file, const char *host, int keytype)
997 found = key_new(keytype);
998 if ((ret = lookup_key_in_hostfile_by_type(file, host,
999 keytype, found, &line))) {
1000 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1001 logit("WARNING: %s key found for host %s\n"
1003 "%s key fingerprint %s.",
1004 key_type(found), host, file, line,
1005 key_type(found), fp);
1012 /* print all known host keys for a given host, but skip keys of given type */
1014 show_other_keys(const char *host, Key *key)
1016 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1019 for (i = 0; type[i] != -1; i++) {
1020 if (type[i] == key->type)
1022 if (type[i] != KEY_RSA1 &&
1023 show_key_from_file(options.user_hostfile2, host, type[i])) {
1027 if (type[i] != KEY_RSA1 &&
1028 show_key_from_file(options.system_hostfile2, host, type[i])) {
1032 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1036 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1040 debug2("no key of type %d for host %s", type[i], host);
1046 warn_changed_key(Key *host_key)
1049 const char *type = key_type(host_key);
1051 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1053 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1054 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1055 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1056 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1057 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1058 error("It is also possible that the %s host key has just been changed.", type);
1059 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1061 error("Please contact your system administrator.");