1 /* $OpenBSD: sshconnect.c,v 1.204 2008/06/11 21:01:35 grunk 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 ms_subtract_diff(struct timeval *start, int *ms)
83 struct timeval diff, finish;
85 gettimeofday(&finish, NULL);
86 timersub(&finish, start, &diff);
87 *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
91 ms_to_timeval(struct timeval *tv, int ms)
93 tv->tv_sec = ms / 1000;
94 tv->tv_usec = (ms % 1000) * 1000;
98 * Connect to the given ssh server using a proxy command.
101 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
103 char *command_string, *tmp;
106 char *shell, strport[NI_MAXSERV];
108 if ((shell = getenv("SHELL")) == NULL)
109 shell = _PATH_BSHELL;
111 /* Convert the port number into a string. */
112 snprintf(strport, sizeof strport, "%hu", port);
115 * Build the final command string in the buffer by making the
116 * appropriate substitutions to the given proxy command.
118 * Use "exec" to avoid "sh -c" processes on some platforms
121 xasprintf(&tmp, "exec %s", proxy_command);
122 command_string = percent_expand(tmp, "h", host,
123 "p", strport, (char *)NULL);
126 /* Create pipes for communicating with the proxy. */
127 if (pipe(pin) < 0 || pipe(pout) < 0)
128 fatal("Could not create pipes to communicate with the proxy: %.100s",
131 debug("Executing proxy command: %.500s", command_string);
133 /* Fork and execute the proxy command. */
134 if ((pid = fork()) == 0) {
137 /* Child. Permanently give up superuser privileges. */
138 permanently_drop_suid(original_real_uid);
140 /* Redirect stdin and stdout. */
143 if (dup2(pin[0], 0) < 0)
144 perror("dup2 stdin");
148 if (dup2(pout[1], 1) < 0)
149 perror("dup2 stdout");
150 /* Cannot be 1 because pin allocated two descriptors. */
153 /* Stderr is left as it is so that error messages get
154 printed on the user's terminal. */
157 argv[2] = command_string;
160 /* Execute the proxy command. Note that we gave up any
161 extra privileges above. */
162 execv(argv[0], argv);
168 fatal("fork failed: %.100s", strerror(errno));
170 proxy_command_pid = pid; /* save pid to clean up later */
172 /* Close child side of the descriptors. */
176 /* Free the command name. */
177 xfree(command_string);
179 /* Set the connection file descriptors. */
180 packet_set_connection(pout[0], pin[1]);
182 /* Indicate OK return */
187 * Creates a (possibly privileged) socket for use as the ssh connection.
190 ssh_create_socket(int privileged, struct addrinfo *ai)
193 struct addrinfo hints, *res;
196 * If we are running as root and want to connect to a privileged
197 * port, bind our own socket to a privileged port.
200 int p = IPPORT_RESERVED - 1;
202 sock = rresvport_af(&p, ai->ai_family);
205 error("rresvport: af=%d %.100s", ai->ai_family,
208 debug("Allocated local port %d.", p);
211 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
213 error("socket: %.100s", strerror(errno));
215 /* Bind the socket to an alternative local IP address */
216 if (options.bind_address == NULL)
219 memset(&hints, 0, sizeof(hints));
220 hints.ai_family = ai->ai_family;
221 hints.ai_socktype = ai->ai_socktype;
222 hints.ai_protocol = ai->ai_protocol;
223 hints.ai_flags = AI_PASSIVE;
224 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
226 error("getaddrinfo: %s: %s", options.bind_address,
227 ssh_gai_strerror(gaierr));
231 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
232 error("bind: %s: %s", options.bind_address, strerror(errno));
242 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
243 socklen_t addrlen, int *timeoutp)
246 struct timeval tv, t_start;
248 int optval, rc, result = -1;
250 gettimeofday(&t_start, NULL);
252 if (*timeoutp <= 0) {
253 result = connect(sockfd, serv_addr, addrlen);
257 set_nonblock(sockfd);
258 rc = connect(sockfd, serv_addr, addrlen);
260 unset_nonblock(sockfd);
264 if (errno != EINPROGRESS) {
269 fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
271 FD_SET(sockfd, fdset);
272 ms_to_timeval(&tv, *timeoutp);
275 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
276 if (rc != -1 || errno != EINTR)
287 debug("select: %s", strerror(errno));
290 /* Completed or failed */
292 optlen = sizeof(optval);
293 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
295 debug("getsockopt: %s", strerror(errno));
303 unset_nonblock(sockfd);
306 /* Should not occur */
307 fatal("Bogus return (%d) from select()", rc);
313 if (result == 0 && *timeoutp > 0) {
314 ms_subtract_diff(&t_start, timeoutp);
315 if (*timeoutp <= 0) {
325 * Opens a TCP/IP connection to the remote server on the given host.
326 * The address of the remote host will be returned in hostaddr.
327 * If port is 0, the default port will be used. If needpriv is true,
328 * a privileged port will be allocated to make the connection.
329 * This requires super-user privileges if needpriv is true.
330 * Connection_attempts specifies the maximum number of tries (one per
331 * second). If proxy_command is non-NULL, it specifies the command (with %h
332 * and %p substituted for host and port, respectively) to use to contact
336 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
337 u_short port, int family, int connection_attempts, int *timeout_ms,
338 int want_keepalive, int needpriv, const char *proxy_command)
342 int sock = -1, attempt;
343 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
344 struct addrinfo hints, *ai, *aitop;
346 debug2("ssh_connect: needpriv %d", needpriv);
348 /* If a proxy command is given, connect using it. */
349 if (proxy_command != NULL)
350 return ssh_proxy_connect(host, port, proxy_command);
352 /* No proxy command. */
354 memset(&hints, 0, sizeof(hints));
355 hints.ai_family = family;
356 hints.ai_socktype = SOCK_STREAM;
357 snprintf(strport, sizeof strport, "%u", port);
358 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
359 fatal("%s: Could not resolve hostname %.100s: %s", __progname,
360 host, ssh_gai_strerror(gaierr));
362 for (attempt = 0; attempt < connection_attempts; attempt++) {
364 /* Sleep a moment before retrying. */
366 debug("Trying again...");
369 * Loop through addresses for this host, and try each one in
370 * sequence until the connection succeeds.
372 for (ai = aitop; ai; ai = ai->ai_next) {
373 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
375 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
376 ntop, sizeof(ntop), strport, sizeof(strport),
377 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
378 error("ssh_connect: getnameinfo failed");
381 debug("Connecting to %.200s [%.100s] port %s.",
382 host, ntop, strport);
384 /* Create a socket for connecting. */
385 sock = ssh_create_socket(needpriv, ai);
387 /* Any error is already output */
390 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
392 /* Successful connection. */
393 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
396 debug("connect to address %s port %s: %s",
397 ntop, strport, strerror(errno));
403 break; /* Successful connection. */
408 /* Return failure if we didn't get a successful connection. */
410 error("ssh: connect to host %s port %s: %s",
411 host, strport, strerror(errno));
415 debug("Connection established.");
417 /* Set SO_KEEPALIVE if requested. */
418 if (want_keepalive &&
419 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
421 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
423 /* Set the connection. */
424 packet_set_connection(sock, sock);
430 * Waits for the server identification string, and sends our own
431 * identification string.
434 ssh_exchange_identification(int timeout_ms)
436 char buf[256], remote_version[256]; /* must be same size! */
437 int remote_major, remote_minor, mismatch;
438 int connection_in = packet_get_connection_in();
439 int connection_out = packet_get_connection_out();
440 int minor1 = PROTOCOL_MINOR_1;
443 int fdsetsz, remaining, rc;
444 struct timeval t_start, t_remaining;
447 fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
448 fdset = xcalloc(1, fdsetsz);
450 /* Read other side's version identification. */
451 remaining = timeout_ms;
453 for (i = 0; i < sizeof(buf) - 1; i++) {
454 if (timeout_ms > 0) {
455 gettimeofday(&t_start, NULL);
456 ms_to_timeval(&t_remaining, remaining);
457 FD_SET(connection_in, fdset);
458 rc = select(connection_in + 1, fdset, NULL,
459 fdset, &t_remaining);
460 ms_subtract_diff(&t_start, &remaining);
461 if (rc == 0 || remaining <= 0)
462 fatal("Connection timed out during "
467 fatal("ssh_exchange_identification: "
468 "select: %s", strerror(errno));
472 len = atomicio(read, connection_in, &buf[i], 1);
474 if (len != 1 && errno == EPIPE)
475 fatal("ssh_exchange_identification: "
476 "Connection closed by remote host");
478 fatal("ssh_exchange_identification: "
479 "read: %.100s", strerror(errno));
480 if (buf[i] == '\r') {
483 continue; /**XXX wait for \n */
485 if (buf[i] == '\n') {
490 fatal("ssh_exchange_identification: "
491 "No banner received");
493 buf[sizeof(buf) - 1] = 0;
494 if (strncmp(buf, "SSH-", 4) == 0)
496 debug("ssh_exchange_identification: %s", buf);
498 server_version_string = xstrdup(buf);
502 * Check that the versions match. In future this might accept
503 * several versions and set appropriate flags to handle them.
505 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
506 &remote_major, &remote_minor, remote_version) != 3)
507 fatal("Bad remote protocol version identification: '%.100s'", buf);
508 debug("Remote protocol version %d.%d, remote software version %.100s",
509 remote_major, remote_minor, remote_version);
511 compat_datafellows(remote_version);
514 switch (remote_major) {
516 if (remote_minor == 99 &&
517 (options.protocol & SSH_PROTO_2) &&
518 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
522 if (!(options.protocol & SSH_PROTO_1)) {
526 if (remote_minor < 3) {
527 fatal("Remote machine has too old SSH software version.");
528 } else if (remote_minor == 3 || remote_minor == 4) {
529 /* We speak 1.3, too. */
532 if (options.forward_agent) {
533 logit("Agent forwarding disabled for protocol 1.3");
534 options.forward_agent = 0;
539 if (options.protocol & SSH_PROTO_2) {
549 fatal("Protocol major versions differ: %d vs. %d",
550 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
552 /* Send our own protocol version identification. */
553 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
554 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
555 compat20 ? PROTOCOL_MINOR_2 : minor1,
557 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
558 fatal("write: %.100s", strerror(errno));
559 client_version_string = xstrdup(buf);
560 chop(client_version_string);
561 chop(server_version_string);
562 debug("Local version string %.100s", client_version_string);
565 /* defaults to 'no' */
567 confirm(const char *prompt)
569 const char *msg, *again = "Please type 'yes' or 'no': ";
573 if (options.batch_mode)
575 for (msg = prompt;;msg = again) {
576 p = read_passphrase(msg, RP_ECHO);
578 (p[0] == '\0') || (p[0] == '\n') ||
579 strncasecmp(p, "no", 2) == 0)
581 if (p && strncasecmp(p, "yes", 3) == 0)
591 * check whether the supplied host key is valid, return -1 if the key
592 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
598 check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
599 Key *host_key, int readonly, const char *user_hostfile,
600 const char *system_hostfile)
603 const char *type = key_type(host_key);
604 char *ip = NULL, *host = NULL;
605 char hostline[1000], *hostp, *fp, *ra;
606 HostStatus host_status;
607 HostStatus ip_status;
608 int r, local = 0, host_ip_differ = 0;
610 char ntop[NI_MAXHOST];
612 int len, host_line, ip_line;
613 const char *host_file = NULL, *ip_file = NULL;
616 * Force accepting of the host key for loopback/localhost. The
617 * problem is that if the home directory is NFS-mounted to multiple
618 * machines, localhost will refer to a different machine in each of
619 * them, and the user will get bogus HOST_CHANGED warnings. This
620 * essentially disables host authentication for localhost; however,
621 * this is probably not a real problem.
623 /** hostaddr == 0! */
624 switch (hostaddr->sa_family) {
626 local = (ntohl(((struct sockaddr_in *)hostaddr)->
627 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
628 salen = sizeof(struct sockaddr_in);
631 local = IN6_IS_ADDR_LOOPBACK(
632 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
633 salen = sizeof(struct sockaddr_in6);
637 salen = sizeof(struct sockaddr_storage);
640 if (options.no_host_authentication_for_localhost == 1 && local &&
641 options.host_key_alias == NULL) {
642 debug("Forcing accepting of host key for "
643 "loopback/localhost.");
648 * We don't have the remote ip-address for connections
649 * using a proxy command
651 if (options.proxy_command == NULL) {
652 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
653 NULL, 0, NI_NUMERICHOST) != 0)
654 fatal("check_host_key: getnameinfo failed");
655 ip = put_host_port(ntop, port);
657 ip = xstrdup("<no hostip for proxy command>");
660 * Turn off check_host_ip if the connection is to localhost, via proxy
661 * command or if we don't have a hostname to compare with
663 if (options.check_host_ip && (local ||
664 strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
665 options.check_host_ip = 0;
668 * Allow the user to record the key under a different name or
669 * differentiate a non-standard port. This is useful for ssh
670 * tunneling over forwarded connections or if you run multiple
671 * sshd's on different ports on the same machine.
673 if (options.host_key_alias != NULL) {
674 host = xstrdup(options.host_key_alias);
675 debug("using hostkeyalias: %s", host);
677 host = put_host_port(hostname, port);
681 * Store the host key from the known host file in here so that we can
682 * compare it with the key for the IP address.
684 file_key = key_new(host_key->type);
687 * Check if the host key is present in the user's list of known
688 * hosts or in the systemwide list.
690 host_file = user_hostfile;
691 host_status = check_host_in_hostfile(host_file, host, host_key,
692 file_key, &host_line);
693 if (host_status == HOST_NEW) {
694 host_file = system_hostfile;
695 host_status = check_host_in_hostfile(host_file, host, host_key,
696 file_key, &host_line);
699 * Also perform check for the ip address, skip the check if we are
700 * localhost or the hostname was an ip address to begin with
702 if (options.check_host_ip) {
703 Key *ip_key = key_new(host_key->type);
705 ip_file = user_hostfile;
706 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
708 if (ip_status == HOST_NEW) {
709 ip_file = system_hostfile;
710 ip_status = check_host_in_hostfile(ip_file, ip,
711 host_key, ip_key, &ip_line);
713 if (host_status == HOST_CHANGED &&
714 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
719 ip_status = host_status;
723 switch (host_status) {
725 /* The host is known and the key matches. */
726 debug("Host '%.200s' is known and matches the %s host key.",
728 debug("Found key in %s:%d", host_file, host_line);
729 if (options.check_host_ip && ip_status == HOST_NEW) {
731 logit("%s host key for IP address "
732 "'%.128s' not in list of known hosts.",
734 else if (!add_host_to_hostfile(user_hostfile, ip,
735 host_key, options.hash_known_hosts))
736 logit("Failed to add the %s host key for IP "
737 "address '%.128s' to the list of known "
738 "hosts (%.30s).", type, ip, user_hostfile);
740 logit("Warning: Permanently added the %s host "
741 "key for IP address '%.128s' to the list "
742 "of known hosts.", type, ip);
743 } else if (options.check_host_ip == SSHCTL_CHECKHOSTIP_FPR) {
744 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
745 ra = key_fingerprint(host_key, SSH_FP_MD5,
747 logit("Host key fingerprint is %s\n%s\n", fp, ra);
753 if (options.host_key_alias == NULL && port != 0 &&
754 port != SSH_DEFAULT_PORT) {
755 debug("checking without port identifier");
756 if (check_host_key(hostname, hostaddr, 0, host_key, 2,
757 user_hostfile, system_hostfile) == 0) {
758 debug("found matching key w/out port");
764 /* The host is new. */
765 if (options.strict_host_key_checking == 1) {
767 * User has requested strict host key checking. We
768 * will not add the host key automatically. The only
769 * alternative left is to abort.
771 error("No %s host key is known for %.200s and you "
772 "have requested strict checking.", type, host);
774 } else if (options.strict_host_key_checking == 2) {
775 char msg1[1024], msg2[1024];
777 if (show_other_keys(host, host_key))
778 snprintf(msg1, sizeof(msg1),
779 "\nbut keys of different type are already"
780 " known for this host.");
782 snprintf(msg1, sizeof(msg1), ".");
784 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
785 ra = key_fingerprint(host_key, SSH_FP_MD5,
788 if (options.verify_host_key_dns) {
789 if (matching_host_key_dns)
790 snprintf(msg2, sizeof(msg2),
791 "Matching host key fingerprint"
794 snprintf(msg2, sizeof(msg2),
795 "No matching host key fingerprint"
798 snprintf(msg, sizeof(msg),
799 "The authenticity of host '%.200s (%s)' can't be "
801 "%s key fingerprint is %s.\n%s\n%s"
802 "Are you sure you want to continue connecting "
804 host, ip, msg1, type, fp, ra, msg2);
811 * If not in strict mode, add the key automatically to the
812 * local known_hosts file.
814 if (options.check_host_ip && ip_status == HOST_NEW) {
815 snprintf(hostline, sizeof(hostline), "%s,%s",
818 if (options.hash_known_hosts) {
819 /* Add hash of host and IP separately */
820 r = add_host_to_hostfile(user_hostfile, host,
821 host_key, options.hash_known_hosts) &&
822 add_host_to_hostfile(user_hostfile, ip,
823 host_key, options.hash_known_hosts);
825 /* Add unhashed "host,ip" */
826 r = add_host_to_hostfile(user_hostfile,
828 options.hash_known_hosts);
831 r = add_host_to_hostfile(user_hostfile, host, host_key,
832 options.hash_known_hosts);
837 logit("Failed to add the host to the list of known "
838 "hosts (%.500s).", user_hostfile);
840 logit("Warning: Permanently added '%.200s' (%s) to the "
841 "list of known hosts.", hostp, type);
844 if (readonly == ROQUIET)
846 if (options.check_host_ip && host_ip_differ) {
848 if (ip_status == HOST_NEW)
849 key_msg = "is unknown";
850 else if (ip_status == HOST_OK)
851 key_msg = "is unchanged";
853 key_msg = "has a different value";
854 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
855 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
856 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
857 error("The %s host key for %s has changed,", type, host);
858 error("and the key for the according IP address %s", ip);
859 error("%s. This could either mean that", key_msg);
860 error("DNS SPOOFING is happening or the IP address for the host");
861 error("and its host key have changed at the same time.");
862 if (ip_status != HOST_NEW)
863 error("Offending key for IP in %s:%d", ip_file, ip_line);
865 /* The host key has changed. */
866 warn_changed_key(host_key);
867 error("Add correct host key in %.100s to get rid of this message.",
869 error("Offending key in %s:%d", host_file, host_line);
872 * If strict host key checking is in use, the user will have
873 * to edit the key manually and we can only abort.
875 if (options.strict_host_key_checking) {
876 error("%s host key for %.200s has changed and you have "
877 "requested strict checking.", type, host);
882 * If strict host key checking has not been requested, allow
883 * the connection but without MITM-able authentication or
886 if (options.password_authentication) {
887 error("Password authentication is disabled to avoid "
888 "man-in-the-middle attacks.");
889 options.password_authentication = 0;
891 if (options.kbd_interactive_authentication) {
892 error("Keyboard-interactive authentication is disabled"
893 " to avoid man-in-the-middle attacks.");
894 options.kbd_interactive_authentication = 0;
895 options.challenge_response_authentication = 0;
897 if (options.challenge_response_authentication) {
898 error("Challenge/response authentication is disabled"
899 " to avoid man-in-the-middle attacks.");
900 options.challenge_response_authentication = 0;
902 if (options.forward_agent) {
903 error("Agent forwarding is disabled to avoid "
904 "man-in-the-middle attacks.");
905 options.forward_agent = 0;
907 if (options.forward_x11) {
908 error("X11 forwarding is disabled to avoid "
909 "man-in-the-middle attacks.");
910 options.forward_x11 = 0;
912 if (options.num_local_forwards > 0 ||
913 options.num_remote_forwards > 0) {
914 error("Port forwarding is disabled to avoid "
915 "man-in-the-middle attacks.");
916 options.num_local_forwards =
917 options.num_remote_forwards = 0;
919 if (options.tun_open != SSH_TUNMODE_NO) {
920 error("Tunnel forwarding is disabled to avoid "
921 "man-in-the-middle attacks.");
922 options.tun_open = SSH_TUNMODE_NO;
925 * XXX Should permit the user to change to use the new id.
926 * This could be done by converting the host key to an
927 * identifying sentence, tell that the host identifies itself
928 * by that sentence, and ask the user if he/she whishes to
929 * accept the authentication.
933 fatal("internal error");
937 if (options.check_host_ip && host_status != HOST_CHANGED &&
938 ip_status == HOST_CHANGED) {
939 snprintf(msg, sizeof(msg),
940 "Warning: the %s host key for '%.200s' "
941 "differs from the key for the IP address '%.128s'"
942 "\nOffending key for IP in %s:%d",
943 type, host, ip, ip_file, ip_line);
944 if (host_status == HOST_OK) {
946 snprintf(msg + len, sizeof(msg) - len,
947 "\nMatching host key in %s:%d",
948 host_file, host_line);
950 if (options.strict_host_key_checking == 1) {
952 error("Exiting, you have requested strict checking.");
954 } else if (options.strict_host_key_checking == 2) {
955 strlcat(msg, "\nAre you sure you want "
956 "to continue connecting (yes/no)? ", sizeof(msg));
974 /* returns 0 if key verifies or -1 if key does NOT verify */
976 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
981 if (options.verify_host_key_dns &&
982 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
984 if (flags & DNS_VERIFY_FOUND) {
986 if (options.verify_host_key_dns == 1 &&
987 flags & DNS_VERIFY_MATCH &&
988 flags & DNS_VERIFY_SECURE)
991 if (flags & DNS_VERIFY_MATCH) {
992 matching_host_key_dns = 1;
994 warn_changed_key(host_key);
995 error("Update the SSHFP RR in DNS with the new "
996 "host key to get rid of this message.");
1001 /* return ok if the key can be found in an old keyfile */
1002 if (stat(options.system_hostfile2, &st) == 0 ||
1003 stat(options.user_hostfile2, &st) == 0) {
1004 if (check_host_key(host, hostaddr, options.port, host_key,
1005 RDONLY, options.user_hostfile2,
1006 options.system_hostfile2) == 0)
1009 return check_host_key(host, hostaddr, options.port, host_key,
1010 RDRW, options.user_hostfile, options.system_hostfile);
1014 * Starts a dialog with the server, and authenticates the current user on the
1015 * server. This does not need any extra privileges. The basic connection
1016 * to the server must already have been established before this is called.
1017 * If login fails, this function prints an error and never returns.
1018 * This function does not require super-user privileges.
1021 ssh_login(Sensitive *sensitive, const char *orighost,
1022 struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms)
1025 char *server_user, *local_user;
1027 local_user = xstrdup(pw->pw_name);
1028 server_user = options.user ? options.user : local_user;
1030 /* Convert the user-supplied hostname into all lowercase. */
1031 host = xstrdup(orighost);
1032 for (cp = host; *cp; cp++)
1034 *cp = (char)tolower(*cp);
1036 /* Exchange protocol version identification strings with the server. */
1037 ssh_exchange_identification(timeout_ms);
1039 /* Put the connection into non-blocking mode. */
1040 packet_set_nonblocking();
1043 /* authenticate user */
1045 ssh_kex2(host, hostaddr);
1046 ssh_userauth2(local_user, server_user, host, sensitive);
1048 ssh_kex(host, hostaddr);
1049 ssh_userauth1(local_user, server_user, host, sensitive);
1055 ssh_put_password(char *password)
1060 if (datafellows & SSH_BUG_PASSWORDPAD) {
1061 packet_put_cstring(password);
1064 size = roundup(strlen(password) + 1, 32);
1065 padded = xcalloc(1, size);
1066 strlcpy(padded, password, size);
1067 packet_put_string(padded, size);
1068 memset(padded, 0, size);
1073 show_key_from_file(const char *file, const char *host, int keytype)
1079 found = key_new(keytype);
1080 if ((ret = lookup_key_in_hostfile_by_type(file, host,
1081 keytype, found, &line))) {
1082 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1083 ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART);
1084 logit("WARNING: %s key found for host %s\n"
1086 "%s key fingerprint %s.\n%s\n",
1087 key_type(found), host, file, line,
1088 key_type(found), fp, ra);
1096 /* print all known host keys for a given host, but skip keys of given type */
1098 show_other_keys(const char *host, Key *key)
1100 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1103 for (i = 0; type[i] != -1; i++) {
1104 if (type[i] == key->type)
1106 if (type[i] != KEY_RSA1 &&
1107 show_key_from_file(options.user_hostfile2, host, type[i])) {
1111 if (type[i] != KEY_RSA1 &&
1112 show_key_from_file(options.system_hostfile2, host, type[i])) {
1116 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1120 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1124 debug2("no key of type %d for host %s", type[i], host);
1130 warn_changed_key(Key *host_key)
1133 const char *type = key_type(host_key);
1135 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1137 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1138 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1139 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1140 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1141 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1142 error("It is also possible that the %s host key has just been changed.", type);
1143 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1145 error("Please contact your system administrator.");
1151 * Execute a local command
1154 ssh_local_cmd(const char *args)
1160 if (!options.permit_local_command ||
1161 args == NULL || !*args)
1164 if ((shell = getenv("SHELL")) == NULL)
1165 shell = _PATH_BSHELL;
1169 debug3("Executing %s -c \"%s\"", shell, args);
1170 execl(shell, shell, "-c", args, (char *)NULL);
1171 error("Couldn't execute %s -c \"%s\": %s",
1172 shell, args, strerror(errno));
1174 } else if (pid == -1)
1175 fatal("fork failed: %.100s", strerror(errno));
1176 while (waitpid(pid, &status, 0) == -1)
1178 fatal("Couldn't wait for child: %s", strerror(errno));
1180 if (!WIFEXITED(status))
1183 return (WEXITSTATUS(status));