1 /* $OpenBSD: sshconnect.c,v 1.199 2006/08/03 03:34:42 deraadt Exp $ */
3 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * Code to connect to a remote host, and to perform the client side of the
7 * login (authentication) dialog.
9 * As far as I am concerned, the code I have written for this software
10 * can be used freely for any purpose. Any derived versions of this
11 * software must be clearly marked as such, and if the derived work is
12 * incompatible with the protocol description in the RFC file, it must be
13 * called by a name other than "ssh" or "Secure Shell".
18 #include <sys/types.h>
21 #include <sys/socket.h>
22 #ifdef HAVE_SYS_TIME_H
23 # include <sys/time.h>
26 #include <netinet/in.h>
27 #include <arpa/inet.h>
52 #include "sshconnect.h"
61 char *client_version_string = NULL;
62 char *server_version_string = NULL;
64 static int matching_host_key_dns = 0;
67 extern Options options;
68 extern char *__progname;
69 extern uid_t original_real_uid;
70 extern uid_t original_effective_uid;
71 extern pid_t proxy_command_pid;
73 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
74 #define INET6_ADDRSTRLEN 46
77 static int show_other_keys(const char *, Key *);
78 static void warn_changed_key(Key *);
81 * Connect to the given ssh server using a proxy command.
84 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
86 char *command_string, *tmp;
89 char strport[NI_MAXSERV];
91 /* Convert the port number into a string. */
92 snprintf(strport, sizeof strport, "%hu", port);
95 * Build the final command string in the buffer by making the
96 * appropriate substitutions to the given proxy command.
98 * Use "exec" to avoid "sh -c" processes on some platforms
101 xasprintf(&tmp, "exec %s", proxy_command);
102 command_string = percent_expand(tmp, "h", host,
103 "p", strport, (char *)NULL);
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 permanently_drop_suid(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 xfree(command_string);
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 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 fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
244 FD_SET(sockfd, fdset);
249 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
250 if (rc != -1 || errno != EINTR)
261 debug("select: %s", strerror(errno));
264 /* Completed or failed */
266 optlen = sizeof(optval);
267 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
269 debug("getsockopt: %s", strerror(errno));
277 unset_nonblock(sockfd);
280 /* Should not occur */
281 fatal("Bogus return (%d) from select()", rc);
289 * Opens a TCP/IP connection to the remote server on the given host.
290 * The address of the remote host will be returned in hostaddr.
291 * If port is 0, the default port will be used. If needpriv is true,
292 * a privileged port will be allocated to make the connection.
293 * This requires super-user privileges if needpriv is true.
294 * Connection_attempts specifies the maximum number of tries (one per
295 * second). If proxy_command is non-NULL, it specifies the command (with %h
296 * and %p substituted for host and port, respectively) to use to contact
300 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
301 u_short port, int family, int connection_attempts,
302 int needpriv, const char *proxy_command)
306 int sock = -1, attempt;
307 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
308 struct addrinfo hints, *ai, *aitop;
310 debug2("ssh_connect: needpriv %d", needpriv);
312 /* If a proxy command is given, connect using it. */
313 if (proxy_command != NULL)
314 return ssh_proxy_connect(host, port, proxy_command);
316 /* No proxy command. */
318 memset(&hints, 0, sizeof(hints));
319 hints.ai_family = family;
320 hints.ai_socktype = SOCK_STREAM;
321 snprintf(strport, sizeof strport, "%u", port);
322 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
323 fatal("%s: %.100s: %s", __progname, host,
324 gai_strerror(gaierr));
326 for (attempt = 0; attempt < connection_attempts; attempt++) {
328 debug("Trying again...");
331 * Loop through addresses for this host, and try each one in
332 * sequence until the connection succeeds.
334 for (ai = aitop; ai; ai = ai->ai_next) {
335 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
337 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
338 ntop, sizeof(ntop), strport, sizeof(strport),
339 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
340 error("ssh_connect: getnameinfo failed");
343 debug("Connecting to %.200s [%.100s] port %s.",
344 host, ntop, strport);
346 /* Create a socket for connecting. */
347 sock = ssh_create_socket(needpriv, ai);
349 /* Any error is already output */
352 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
353 options.connection_timeout) >= 0) {
354 /* Successful connection. */
355 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
358 debug("connect to address %s port %s: %s",
359 ntop, strport, strerror(errno));
365 break; /* Successful connection. */
367 /* Sleep a moment before retrying. */
373 /* Return failure if we didn't get a successful connection. */
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 fatal("ssh_exchange_identification: No banner received");
429 buf[sizeof(buf) - 1] = 0;
430 if (strncmp(buf, "SSH-", 4) == 0)
432 debug("ssh_exchange_identification: %s", buf);
434 server_version_string = xstrdup(buf);
437 * Check that the versions match. In future this might accept
438 * several versions and set appropriate flags to handle them.
440 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
441 &remote_major, &remote_minor, remote_version) != 3)
442 fatal("Bad remote protocol version identification: '%.100s'", buf);
443 debug("Remote protocol version %d.%d, remote software version %.100s",
444 remote_major, remote_minor, remote_version);
446 compat_datafellows(remote_version);
449 switch (remote_major) {
451 if (remote_minor == 99 &&
452 (options.protocol & SSH_PROTO_2) &&
453 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
457 if (!(options.protocol & SSH_PROTO_1)) {
461 if (remote_minor < 3) {
462 fatal("Remote machine has too old SSH software version.");
463 } else if (remote_minor == 3 || remote_minor == 4) {
464 /* We speak 1.3, too. */
467 if (options.forward_agent) {
468 logit("Agent forwarding disabled for protocol 1.3");
469 options.forward_agent = 0;
474 if (options.protocol & SSH_PROTO_2) {
484 fatal("Protocol major versions differ: %d vs. %d",
485 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
487 /* Send our own protocol version identification. */
488 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
489 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
490 compat20 ? PROTOCOL_MINOR_2 : minor1,
492 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
493 fatal("write: %.100s", strerror(errno));
494 client_version_string = xstrdup(buf);
495 chop(client_version_string);
496 chop(server_version_string);
497 debug("Local version string %.100s", client_version_string);
500 /* defaults to 'no' */
502 confirm(const char *prompt)
504 const char *msg, *again = "Please type 'yes' or 'no': ";
508 if (options.batch_mode)
510 for (msg = prompt;;msg = again) {
511 p = read_passphrase(msg, RP_ECHO);
513 (p[0] == '\0') || (p[0] == '\n') ||
514 strncasecmp(p, "no", 2) == 0)
516 if (p && strncasecmp(p, "yes", 3) == 0)
526 * check whether the supplied host key is valid, return -1 if the key
527 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
533 check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
534 Key *host_key, int readonly, const char *user_hostfile,
535 const char *system_hostfile)
538 const char *type = key_type(host_key);
539 char *ip = NULL, *host = NULL;
540 char hostline[1000], *hostp, *fp;
541 HostStatus host_status;
542 HostStatus ip_status;
543 int r, local = 0, host_ip_differ = 0;
545 char ntop[NI_MAXHOST];
547 int len, host_line, ip_line;
548 const char *host_file = NULL, *ip_file = NULL;
551 * Force accepting of the host key for loopback/localhost. The
552 * problem is that if the home directory is NFS-mounted to multiple
553 * machines, localhost will refer to a different machine in each of
554 * them, and the user will get bogus HOST_CHANGED warnings. This
555 * essentially disables host authentication for localhost; however,
556 * this is probably not a real problem.
558 /** hostaddr == 0! */
559 switch (hostaddr->sa_family) {
561 local = (ntohl(((struct sockaddr_in *)hostaddr)->
562 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
563 salen = sizeof(struct sockaddr_in);
566 local = IN6_IS_ADDR_LOOPBACK(
567 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
568 salen = sizeof(struct sockaddr_in6);
572 salen = sizeof(struct sockaddr_storage);
575 if (options.no_host_authentication_for_localhost == 1 && local &&
576 options.host_key_alias == NULL) {
577 debug("Forcing accepting of host key for "
578 "loopback/localhost.");
583 * We don't have the remote ip-address for connections
584 * using a proxy command
586 if (options.proxy_command == NULL) {
587 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
588 NULL, 0, NI_NUMERICHOST) != 0)
589 fatal("check_host_key: getnameinfo failed");
590 ip = put_host_port(ntop, port);
592 ip = xstrdup("<no hostip for proxy command>");
595 * Turn off check_host_ip if the connection is to localhost, via proxy
596 * command or if we don't have a hostname to compare with
598 if (options.check_host_ip && (local ||
599 strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
600 options.check_host_ip = 0;
603 * Allow the user to record the key under a different name or
604 * differentiate a non-standard port. This is useful for ssh
605 * tunneling over forwarded connections or if you run multiple
606 * sshd's on different ports on the same machine.
608 if (options.host_key_alias != NULL) {
609 host = xstrdup(options.host_key_alias);
610 debug("using hostkeyalias: %s", host);
612 host = put_host_port(hostname, port);
616 * Store the host key from the known host file in here so that we can
617 * compare it with the key for the IP address.
619 file_key = key_new(host_key->type);
622 * Check if the host key is present in the user's list of known
623 * hosts or in the systemwide list.
625 host_file = user_hostfile;
626 host_status = check_host_in_hostfile(host_file, host, host_key,
627 file_key, &host_line);
628 if (host_status == HOST_NEW) {
629 host_file = system_hostfile;
630 host_status = check_host_in_hostfile(host_file, host, host_key,
631 file_key, &host_line);
634 * Also perform check for the ip address, skip the check if we are
635 * localhost or the hostname was an ip address to begin with
637 if (options.check_host_ip) {
638 Key *ip_key = key_new(host_key->type);
640 ip_file = user_hostfile;
641 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
643 if (ip_status == HOST_NEW) {
644 ip_file = system_hostfile;
645 ip_status = check_host_in_hostfile(ip_file, ip,
646 host_key, ip_key, &ip_line);
648 if (host_status == HOST_CHANGED &&
649 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
654 ip_status = host_status;
658 switch (host_status) {
660 /* The host is known and the key matches. */
661 debug("Host '%.200s' is known and matches the %s host key.",
663 debug("Found key in %s:%d", host_file, host_line);
664 if (options.check_host_ip && ip_status == HOST_NEW) {
666 logit("%s host key for IP address "
667 "'%.128s' not in list of known hosts.",
669 else if (!add_host_to_hostfile(user_hostfile, ip,
670 host_key, options.hash_known_hosts))
671 logit("Failed to add the %s host key for IP "
672 "address '%.128s' to the list of known "
673 "hosts (%.30s).", type, ip, user_hostfile);
675 logit("Warning: Permanently added the %s host "
676 "key for IP address '%.128s' to the list "
677 "of known hosts.", type, ip);
681 if (options.host_key_alias == NULL && port != 0 &&
682 port != SSH_DEFAULT_PORT) {
683 debug("checking without port identifier");
684 if (check_host_key(hostname, hostaddr, 0, host_key, 2,
685 user_hostfile, system_hostfile) == 0) {
686 debug("found matching key w/out port");
692 /* The host is new. */
693 if (options.strict_host_key_checking == 1) {
695 * User has requested strict host key checking. We
696 * will not add the host key automatically. The only
697 * alternative left is to abort.
699 error("No %s host key is known for %.200s and you "
700 "have requested strict checking.", type, host);
702 } else if (options.strict_host_key_checking == 2) {
703 char msg1[1024], msg2[1024];
705 if (show_other_keys(host, host_key))
706 snprintf(msg1, sizeof(msg1),
707 "\nbut keys of different type are already"
708 " known for this host.");
710 snprintf(msg1, sizeof(msg1), ".");
712 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
714 if (options.verify_host_key_dns) {
715 if (matching_host_key_dns)
716 snprintf(msg2, sizeof(msg2),
717 "Matching host key fingerprint"
720 snprintf(msg2, sizeof(msg2),
721 "No matching host key fingerprint"
724 snprintf(msg, sizeof(msg),
725 "The authenticity of host '%.200s (%s)' can't be "
727 "%s key fingerprint is %s.\n%s"
728 "Are you sure you want to continue connecting "
730 host, ip, msg1, type, fp, msg2);
736 * If not in strict mode, add the key automatically to the
737 * local known_hosts file.
739 if (options.check_host_ip && ip_status == HOST_NEW) {
740 snprintf(hostline, sizeof(hostline), "%s,%s",
743 if (options.hash_known_hosts) {
744 /* Add hash of host and IP separately */
745 r = add_host_to_hostfile(user_hostfile, host,
746 host_key, options.hash_known_hosts) &&
747 add_host_to_hostfile(user_hostfile, ip,
748 host_key, options.hash_known_hosts);
750 /* Add unhashed "host,ip" */
751 r = add_host_to_hostfile(user_hostfile,
753 options.hash_known_hosts);
756 r = add_host_to_hostfile(user_hostfile, host, host_key,
757 options.hash_known_hosts);
762 logit("Failed to add the host to the list of known "
763 "hosts (%.500s).", user_hostfile);
765 logit("Warning: Permanently added '%.200s' (%s) to the "
766 "list of known hosts.", hostp, type);
769 if (readonly == ROQUIET)
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;
844 if (options.tun_open != SSH_TUNMODE_NO) {
845 error("Tunnel forwarding is disabled to avoid "
846 "man-in-the-middle attacks.");
847 options.tun_open = SSH_TUNMODE_NO;
850 * XXX Should permit the user to change to use the new id.
851 * This could be done by converting the host key to an
852 * identifying sentence, tell that the host identifies itself
853 * by that sentence, and ask the user if he/she whishes to
854 * accept the authentication.
858 fatal("internal error");
862 if (options.check_host_ip && host_status != HOST_CHANGED &&
863 ip_status == HOST_CHANGED) {
864 snprintf(msg, sizeof(msg),
865 "Warning: the %s host key for '%.200s' "
866 "differs from the key for the IP address '%.128s'"
867 "\nOffending key for IP in %s:%d",
868 type, host, ip, ip_file, ip_line);
869 if (host_status == HOST_OK) {
871 snprintf(msg + len, sizeof(msg) - len,
872 "\nMatching host key in %s:%d",
873 host_file, host_line);
875 if (options.strict_host_key_checking == 1) {
877 error("Exiting, you have requested strict checking.");
879 } else if (options.strict_host_key_checking == 2) {
880 strlcat(msg, "\nAre you sure you want "
881 "to continue connecting (yes/no)? ", sizeof(msg));
899 /* returns 0 if key verifies or -1 if key does NOT verify */
901 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
906 if (options.verify_host_key_dns &&
907 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
909 if (flags & DNS_VERIFY_FOUND) {
911 if (options.verify_host_key_dns == 1 &&
912 flags & DNS_VERIFY_MATCH &&
913 flags & DNS_VERIFY_SECURE)
916 if (flags & DNS_VERIFY_MATCH) {
917 matching_host_key_dns = 1;
919 warn_changed_key(host_key);
920 error("Update the SSHFP RR in DNS with the new "
921 "host key to get rid of this message.");
926 /* return ok if the key can be found in an old keyfile */
927 if (stat(options.system_hostfile2, &st) == 0 ||
928 stat(options.user_hostfile2, &st) == 0) {
929 if (check_host_key(host, hostaddr, options.port, host_key,
930 RDONLY, options.user_hostfile2,
931 options.system_hostfile2) == 0)
934 return check_host_key(host, hostaddr, options.port, host_key,
935 RDRW, options.user_hostfile, options.system_hostfile);
939 * Starts a dialog with the server, and authenticates the current user on the
940 * server. This does not need any extra privileges. The basic connection
941 * to the server must already have been established before this is called.
942 * If login fails, this function prints an error and never returns.
943 * This function does not require super-user privileges.
946 ssh_login(Sensitive *sensitive, const char *orighost,
947 struct sockaddr *hostaddr, struct passwd *pw)
950 char *server_user, *local_user;
952 local_user = xstrdup(pw->pw_name);
953 server_user = options.user ? options.user : local_user;
955 /* Convert the user-supplied hostname into all lowercase. */
956 host = xstrdup(orighost);
957 for (cp = host; *cp; cp++)
959 *cp = (char)tolower(*cp);
961 /* Exchange protocol version identification strings with the server. */
962 ssh_exchange_identification();
964 /* Put the connection into non-blocking mode. */
965 packet_set_nonblocking();
968 /* authenticate user */
970 ssh_kex2(host, hostaddr);
971 ssh_userauth2(local_user, server_user, host, sensitive);
973 ssh_kex(host, hostaddr);
974 ssh_userauth1(local_user, server_user, host, sensitive);
980 ssh_put_password(char *password)
985 if (datafellows & SSH_BUG_PASSWORDPAD) {
986 packet_put_cstring(password);
989 size = roundup(strlen(password) + 1, 32);
990 padded = xcalloc(1, size);
991 strlcpy(padded, password, size);
992 packet_put_string(padded, size);
993 memset(padded, 0, size);
998 show_key_from_file(const char *file, const char *host, int keytype)
1004 found = key_new(keytype);
1005 if ((ret = lookup_key_in_hostfile_by_type(file, host,
1006 keytype, found, &line))) {
1007 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1008 logit("WARNING: %s key found for host %s\n"
1010 "%s key fingerprint %s.",
1011 key_type(found), host, file, line,
1012 key_type(found), fp);
1019 /* print all known host keys for a given host, but skip keys of given type */
1021 show_other_keys(const char *host, Key *key)
1023 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1026 for (i = 0; type[i] != -1; i++) {
1027 if (type[i] == key->type)
1029 if (type[i] != KEY_RSA1 &&
1030 show_key_from_file(options.user_hostfile2, host, type[i])) {
1034 if (type[i] != KEY_RSA1 &&
1035 show_key_from_file(options.system_hostfile2, host, type[i])) {
1039 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1043 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1047 debug2("no key of type %d for host %s", type[i], host);
1053 warn_changed_key(Key *host_key)
1056 const char *type = key_type(host_key);
1058 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1060 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1061 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1062 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1063 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1064 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1065 error("It is also possible that the %s host key has just been changed.", type);
1066 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1068 error("Please contact your system administrator.");
1074 * Execute a local command
1077 ssh_local_cmd(const char *args)
1083 if (!options.permit_local_command ||
1084 args == NULL || !*args)
1087 if ((shell = getenv("SHELL")) == NULL)
1088 shell = _PATH_BSHELL;
1092 debug3("Executing %s -c \"%s\"", shell, args);
1093 execl(shell, shell, "-c", args, (char *)NULL);
1094 error("Couldn't execute %s -c \"%s\": %s",
1095 shell, args, strerror(errno));
1097 } else if (pid == -1)
1098 fatal("fork failed: %.100s", strerror(errno));
1099 while (waitpid(pid, &status, 0) == -1)
1101 fatal("Couldn't wait for child: %s", strerror(errno));
1103 if (!WIFEXITED(status))
1106 return (WEXITSTATUS(status));