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 1.162 2005/03/10 22:01:06 deraadt 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 int len = atomicio(read, connection_in, &buf[i], 1);
434 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
436 fatal("ssh_exchange_identification: Connection closed by remote host");
437 if (buf[i] == '\r') {
440 continue; /**XXX wait for \n */
442 if (buf[i] == '\n') {
447 buf[sizeof(buf) - 1] = 0;
448 if (strncmp(buf, "SSH-", 4) == 0)
450 debug("ssh_exchange_identification: %s", buf);
452 server_version_string = xstrdup(buf);
455 * Check that the versions match. In future this might accept
456 * several versions and set appropriate flags to handle them.
458 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
459 &remote_major, &remote_minor, remote_version) != 3)
460 fatal("Bad remote protocol version identification: '%.100s'", buf);
461 debug("Remote protocol version %d.%d, remote software version %.100s",
462 remote_major, remote_minor, remote_version);
464 compat_datafellows(remote_version);
467 switch (remote_major) {
469 if (remote_minor == 99 &&
470 (options.protocol & SSH_PROTO_2) &&
471 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
475 if (!(options.protocol & SSH_PROTO_1)) {
479 if (remote_minor < 3) {
480 fatal("Remote machine has too old SSH software version.");
481 } else if (remote_minor == 3 || remote_minor == 4) {
482 /* We speak 1.3, too. */
485 if (options.forward_agent) {
486 logit("Agent forwarding disabled for protocol 1.3");
487 options.forward_agent = 0;
492 if (options.protocol & SSH_PROTO_2) {
502 fatal("Protocol major versions differ: %d vs. %d",
503 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
505 /* Send our own protocol version identification. */
506 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
507 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
508 compat20 ? PROTOCOL_MINOR_2 : minor1,
510 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
511 fatal("write: %.100s", strerror(errno));
512 client_version_string = xstrdup(buf);
513 chop(client_version_string);
514 chop(server_version_string);
515 debug("Local version string %.100s", client_version_string);
518 /* defaults to 'no' */
520 confirm(const char *prompt)
522 const char *msg, *again = "Please type 'yes' or 'no': ";
526 if (options.batch_mode)
528 for (msg = prompt;;msg = again) {
529 p = read_passphrase(msg, RP_ECHO);
531 (p[0] == '\0') || (p[0] == '\n') ||
532 strncasecmp(p, "no", 2) == 0)
534 if (p && strncasecmp(p, "yes", 3) == 0)
544 * check whether the supplied host key is valid, return -1 if the key
545 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
548 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
549 int readonly, const char *user_hostfile, const char *system_hostfile)
552 const char *type = key_type(host_key);
554 char hostline[1000], *hostp, *fp;
555 HostStatus host_status;
556 HostStatus ip_status;
557 int r, local = 0, host_ip_differ = 0;
559 char ntop[NI_MAXHOST];
561 int len, host_line, ip_line;
562 const char *host_file = NULL, *ip_file = NULL;
565 * Force accepting of the host key for loopback/localhost. The
566 * problem is that if the home directory is NFS-mounted to multiple
567 * machines, localhost will refer to a different machine in each of
568 * them, and the user will get bogus HOST_CHANGED warnings. This
569 * essentially disables host authentication for localhost; however,
570 * this is probably not a real problem.
572 /** hostaddr == 0! */
573 switch (hostaddr->sa_family) {
575 local = (ntohl(((struct sockaddr_in *)hostaddr)->
576 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
577 salen = sizeof(struct sockaddr_in);
580 local = IN6_IS_ADDR_LOOPBACK(
581 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
582 salen = sizeof(struct sockaddr_in6);
586 salen = sizeof(struct sockaddr_storage);
589 if (options.no_host_authentication_for_localhost == 1 && local &&
590 options.host_key_alias == NULL) {
591 debug("Forcing accepting of host key for "
592 "loopback/localhost.");
597 * We don't have the remote ip-address for connections
598 * using a proxy command
600 if (options.proxy_command == NULL) {
601 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
602 NULL, 0, NI_NUMERICHOST) != 0)
603 fatal("check_host_key: getnameinfo failed");
606 ip = xstrdup("<no hostip for proxy command>");
609 * Turn off check_host_ip if the connection is to localhost, via proxy
610 * command or if we don't have a hostname to compare with
612 if (options.check_host_ip &&
613 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
614 options.check_host_ip = 0;
617 * Allow the user to record the key under a different name. This is
618 * useful for ssh tunneling over forwarded connections or if you run
619 * multiple sshd's on different ports on the same machine.
621 if (options.host_key_alias != NULL) {
622 host = options.host_key_alias;
623 debug("using hostkeyalias: %s", host);
627 * Store the host key from the known host file in here so that we can
628 * compare it with the key for the IP address.
630 file_key = key_new(host_key->type);
633 * Check if the host key is present in the user\'s list of known
634 * hosts or in the systemwide list.
636 host_file = user_hostfile;
637 host_status = check_host_in_hostfile(host_file, host, host_key,
638 file_key, &host_line);
639 if (host_status == HOST_NEW) {
640 host_file = system_hostfile;
641 host_status = check_host_in_hostfile(host_file, host, host_key,
642 file_key, &host_line);
645 * Also perform check for the ip address, skip the check if we are
646 * localhost or the hostname was an ip address to begin with
648 if (options.check_host_ip) {
649 Key *ip_key = key_new(host_key->type);
651 ip_file = user_hostfile;
652 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
654 if (ip_status == HOST_NEW) {
655 ip_file = system_hostfile;
656 ip_status = check_host_in_hostfile(ip_file, ip,
657 host_key, ip_key, &ip_line);
659 if (host_status == HOST_CHANGED &&
660 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
665 ip_status = host_status;
669 switch (host_status) {
671 /* The host is known and the key matches. */
672 debug("Host '%.200s' is known and matches the %s host key.",
674 debug("Found key in %s:%d", host_file, host_line);
675 if (options.check_host_ip && ip_status == HOST_NEW) {
677 logit("%s host key for IP address "
678 "'%.128s' not in list of known hosts.",
680 else if (!add_host_to_hostfile(user_hostfile, ip,
681 host_key, options.hash_known_hosts))
682 logit("Failed to add the %s host key for IP "
683 "address '%.128s' to the list of known "
684 "hosts (%.30s).", type, ip, user_hostfile);
686 logit("Warning: Permanently added the %s host "
687 "key for IP address '%.128s' to the list "
688 "of known hosts.", type, ip);
694 /* The host is new. */
695 if (options.strict_host_key_checking == 1) {
697 * User has requested strict host key checking. We
698 * will not add the host key automatically. The only
699 * alternative left is to abort.
701 error("No %s host key is known for %.200s and you "
702 "have requested strict checking.", type, host);
704 } else if (options.strict_host_key_checking == 2) {
705 char msg1[1024], msg2[1024];
707 if (show_other_keys(host, host_key))
708 snprintf(msg1, sizeof(msg1),
709 "\nbut keys of different type are already"
710 " known for this host.");
712 snprintf(msg1, sizeof(msg1), ".");
714 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
716 if (options.verify_host_key_dns) {
717 if (matching_host_key_dns)
718 snprintf(msg2, sizeof(msg2),
719 "Matching host key fingerprint"
722 snprintf(msg2, sizeof(msg2),
723 "No matching host key fingerprint"
726 snprintf(msg, sizeof(msg),
727 "The authenticity of host '%.200s (%s)' can't be "
729 "%s key fingerprint is %s.\n%s"
730 "Are you sure you want to continue connecting "
732 host, ip, msg1, type, fp, msg2);
738 * If not in strict mode, add the key automatically to the
739 * local known_hosts file.
741 if (options.check_host_ip && ip_status == HOST_NEW) {
742 snprintf(hostline, sizeof(hostline), "%s,%s",
745 if (options.hash_known_hosts) {
746 /* Add hash of host and IP separately */
747 r = add_host_to_hostfile(user_hostfile, host,
748 host_key, options.hash_known_hosts) &&
749 add_host_to_hostfile(user_hostfile, ip,
750 host_key, options.hash_known_hosts);
752 /* Add unhashed "host,ip" */
753 r = add_host_to_hostfile(user_hostfile,
755 options.hash_known_hosts);
758 r = add_host_to_hostfile(user_hostfile, host, host_key,
759 options.hash_known_hosts);
764 logit("Failed to add the host to the list of known "
765 "hosts (%.500s).", user_hostfile);
767 logit("Warning: Permanently added '%.200s' (%s) to the "
768 "list of known hosts.", hostp, type);
771 if (options.check_host_ip && host_ip_differ) {
773 if (ip_status == HOST_NEW)
774 key_msg = "is unknown";
775 else if (ip_status == HOST_OK)
776 key_msg = "is unchanged";
778 key_msg = "has a different value";
779 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
780 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
781 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
782 error("The %s host key for %s has changed,", type, host);
783 error("and the key for the according IP address %s", ip);
784 error("%s. This could either mean that", key_msg);
785 error("DNS SPOOFING is happening or the IP address for the host");
786 error("and its host key have changed at the same time.");
787 if (ip_status != HOST_NEW)
788 error("Offending key for IP in %s:%d", ip_file, ip_line);
790 /* The host key has changed. */
791 warn_changed_key(host_key);
792 error("Add correct host key in %.100s to get rid of this message.",
794 error("Offending key in %s:%d", host_file, host_line);
797 * If strict host key checking is in use, the user will have
798 * to edit the key manually and we can only abort.
800 if (options.strict_host_key_checking) {
801 error("%s host key for %.200s has changed and you have "
802 "requested strict checking.", type, host);
807 * If strict host key checking has not been requested, allow
808 * the connection but without MITM-able authentication or
811 if (options.password_authentication) {
812 error("Password authentication is disabled to avoid "
813 "man-in-the-middle attacks.");
814 options.password_authentication = 0;
816 if (options.kbd_interactive_authentication) {
817 error("Keyboard-interactive authentication is disabled"
818 " to avoid man-in-the-middle attacks.");
819 options.kbd_interactive_authentication = 0;
820 options.challenge_response_authentication = 0;
822 if (options.challenge_response_authentication) {
823 error("Challenge/response authentication is disabled"
824 " to avoid man-in-the-middle attacks.");
825 options.challenge_response_authentication = 0;
827 if (options.forward_agent) {
828 error("Agent forwarding is disabled to avoid "
829 "man-in-the-middle attacks.");
830 options.forward_agent = 0;
832 if (options.forward_x11) {
833 error("X11 forwarding is disabled to avoid "
834 "man-in-the-middle attacks.");
835 options.forward_x11 = 0;
837 if (options.num_local_forwards > 0 ||
838 options.num_remote_forwards > 0) {
839 error("Port forwarding is disabled to avoid "
840 "man-in-the-middle attacks.");
841 options.num_local_forwards =
842 options.num_remote_forwards = 0;
845 * XXX Should permit the user to change to use the new id.
846 * This could be done by converting the host key to an
847 * identifying sentence, tell that the host identifies itself
848 * by that sentence, and ask the user if he/she whishes to
849 * accept the authentication.
853 fatal("internal error");
857 if (options.check_host_ip && host_status != HOST_CHANGED &&
858 ip_status == HOST_CHANGED) {
859 snprintf(msg, sizeof(msg),
860 "Warning: the %s host key for '%.200s' "
861 "differs from the key for the IP address '%.128s'"
862 "\nOffending key for IP in %s:%d",
863 type, host, ip, ip_file, ip_line);
864 if (host_status == HOST_OK) {
866 snprintf(msg + len, sizeof(msg) - len,
867 "\nMatching host key in %s:%d",
868 host_file, host_line);
870 if (options.strict_host_key_checking == 1) {
872 error("Exiting, you have requested strict checking.");
874 } else if (options.strict_host_key_checking == 2) {
875 strlcat(msg, "\nAre you sure you want "
876 "to continue connecting (yes/no)? ", sizeof(msg));
892 /* returns 0 if key verifies or -1 if key does NOT verify */
894 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
899 if (options.verify_host_key_dns &&
900 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
902 if (flags & DNS_VERIFY_FOUND) {
904 if (options.verify_host_key_dns == 1 &&
905 flags & DNS_VERIFY_MATCH &&
906 flags & DNS_VERIFY_SECURE)
909 if (flags & DNS_VERIFY_MATCH) {
910 matching_host_key_dns = 1;
912 warn_changed_key(host_key);
913 error("Update the SSHFP RR in DNS with the new "
914 "host key to get rid of this message.");
919 /* return ok if the key can be found in an old keyfile */
920 if (stat(options.system_hostfile2, &st) == 0 ||
921 stat(options.user_hostfile2, &st) == 0) {
922 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
923 options.user_hostfile2, options.system_hostfile2) == 0)
926 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
927 options.user_hostfile, options.system_hostfile);
931 * Starts a dialog with the server, and authenticates the current user on the
932 * server. This does not need any extra privileges. The basic connection
933 * to the server must already have been established before this is called.
934 * If login fails, this function prints an error and never returns.
935 * This function does not require super-user privileges.
938 ssh_login(Sensitive *sensitive, const char *orighost,
939 struct sockaddr *hostaddr, struct passwd *pw)
942 char *server_user, *local_user;
944 local_user = xstrdup(pw->pw_name);
945 server_user = options.user ? options.user : local_user;
947 /* Convert the user-supplied hostname into all lowercase. */
948 host = xstrdup(orighost);
949 for (cp = host; *cp; cp++)
953 /* Exchange protocol version identification strings with the server. */
954 ssh_exchange_identification();
956 /* Put the connection into non-blocking mode. */
957 packet_set_nonblocking();
960 /* authenticate user */
962 ssh_kex2(host, hostaddr);
963 ssh_userauth2(local_user, server_user, host, sensitive);
965 ssh_kex(host, hostaddr);
966 ssh_userauth1(local_user, server_user, host, sensitive);
971 ssh_put_password(char *password)
976 if (datafellows & SSH_BUG_PASSWORDPAD) {
977 packet_put_cstring(password);
980 size = roundup(strlen(password) + 1, 32);
981 padded = xmalloc(size);
982 memset(padded, 0, size);
983 strlcpy(padded, password, size);
984 packet_put_string(padded, size);
985 memset(padded, 0, size);
990 show_key_from_file(const char *file, const char *host, int keytype)
996 found = key_new(keytype);
997 if ((ret = lookup_key_in_hostfile_by_type(file, host,
998 keytype, found, &line))) {
999 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1000 logit("WARNING: %s key found for host %s\n"
1002 "%s key fingerprint %s.",
1003 key_type(found), host, file, line,
1004 key_type(found), fp);
1011 /* print all known host keys for a given host, but skip keys of given type */
1013 show_other_keys(const char *host, Key *key)
1015 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1018 for (i = 0; type[i] != -1; i++) {
1019 if (type[i] == key->type)
1021 if (type[i] != KEY_RSA1 &&
1022 show_key_from_file(options.user_hostfile2, host, type[i])) {
1026 if (type[i] != KEY_RSA1 &&
1027 show_key_from_file(options.system_hostfile2, host, type[i])) {
1031 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1035 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1039 debug2("no key of type %d for host %s", type[i], host);
1045 warn_changed_key(Key *host_key)
1048 const char *type = key_type(host_key);
1050 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1052 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1053 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1054 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1055 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1056 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1057 error("It is also possible that the %s host key has just been changed.", type);
1058 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1060 error("Please contact your system administrator.");