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 1.168 2005/07/17 07:17:55 djm 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)
62 char *command_string, *tmp;
65 char strport[NI_MAXSERV];
68 /* Convert the port number into a string. */
69 snprintf(strport, sizeof strport, "%hu", port);
72 * Build the final command string in the buffer by making the
73 * appropriate substitutions to the given proxy command.
75 * Use "exec" to avoid "sh -c" processes on some platforms
78 len = strlen(proxy_command) + 6;
80 strlcpy(tmp, "exec ", len);
81 strlcat(tmp, proxy_command, len);
82 command_string = percent_expand(tmp, "h", host,
83 "p", strport, (char *)NULL);
86 /* Create pipes for communicating with the proxy. */
87 if (pipe(pin) < 0 || pipe(pout) < 0)
88 fatal("Could not create pipes to communicate with the proxy: %.100s",
91 debug("Executing proxy command: %.500s", command_string);
93 /* Fork and execute the proxy command. */
94 if ((pid = fork()) == 0) {
97 /* Child. Permanently give up superuser privileges. */
98 seteuid(original_real_uid);
99 setuid(original_real_uid);
101 /* Redirect stdin and stdout. */
104 if (dup2(pin[0], 0) < 0)
105 perror("dup2 stdin");
109 if (dup2(pout[1], 1) < 0)
110 perror("dup2 stdout");
111 /* Cannot be 1 because pin allocated two descriptors. */
114 /* Stderr is left as it is so that error messages get
115 printed on the user's terminal. */
116 argv[0] = _PATH_BSHELL;
118 argv[2] = command_string;
121 /* Execute the proxy command. Note that we gave up any
122 extra privileges above. */
123 execv(argv[0], argv);
129 fatal("fork failed: %.100s", strerror(errno));
131 proxy_command_pid = pid; /* save pid to clean up later */
133 /* Close child side of the descriptors. */
137 /* Free the command name. */
138 xfree(command_string);
140 /* Set the connection file descriptors. */
141 packet_set_connection(pout[0], pin[1]);
143 /* Indicate OK return */
148 * Creates a (possibly privileged) socket for use as the ssh connection.
151 ssh_create_socket(int privileged, struct addrinfo *ai)
154 struct addrinfo hints, *res;
157 * If we are running as root and want to connect to a privileged
158 * port, bind our own socket to a privileged port.
161 int p = IPPORT_RESERVED - 1;
163 sock = rresvport_af(&p, ai->ai_family);
166 error("rresvport: af=%d %.100s", ai->ai_family,
169 debug("Allocated local port %d.", p);
172 /* tuning needs to happen after the socket is */
173 /* created but before the connection happens */
174 /* so winscale is negotiated properly -cjr */
176 /* Set tcp receive buffer if requested */
177 if (options.tcp_rcv_buf)
179 if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
180 (void *)&options.tcp_rcv_buf,
181 sizeof(options.tcp_rcv_buf)) >= 0)
183 debug("setsockopt SO_RCVBUF: %.100s", strerror(errno));
187 /* coudln't set the socket size to use spec. */
188 /* should default to system param and continue */
189 /* warn the user though - cjr */
190 error("Couldn't set socket receive buffer as requested. Continuing anyway.");
195 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
197 error("socket: %.100s", strerror(errno));
199 /* tuning needs to happen after the socket is */
200 /* created but before the connection happens */
201 /* so winscale is negotiated properly -cjr */
203 /* Set tcp receive buffer if requested */
204 if (options.tcp_rcv_buf)
206 if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF,
207 (void *)&options.tcp_rcv_buf,
208 sizeof(options.tcp_rcv_buf)) >= 0)
210 debug("setsockopt SO_RCVBUF: %.100s", strerror(errno));
214 /* coudln't set the socket size to use spec. */
215 /* should default to system param and continue */
216 /* warn the user though - cjr */
217 error("Couldn't set socket receive buffer as requested. Continuing anyway.");
221 /* Bind the socket to an alternative local IP address */
222 if (options.bind_address == NULL)
225 memset(&hints, 0, sizeof(hints));
226 hints.ai_family = ai->ai_family;
227 hints.ai_socktype = ai->ai_socktype;
228 hints.ai_protocol = ai->ai_protocol;
229 hints.ai_flags = AI_PASSIVE;
230 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
232 error("getaddrinfo: %s: %s", options.bind_address,
233 gai_strerror(gaierr));
237 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
238 error("bind: %s: %s", options.bind_address, strerror(errno));
248 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
249 socklen_t addrlen, int timeout)
254 int fdsetsz, optval, rc, result = -1;
257 return (connect(sockfd, serv_addr, addrlen));
259 set_nonblock(sockfd);
260 rc = connect(sockfd, serv_addr, addrlen);
262 unset_nonblock(sockfd);
265 if (errno != EINPROGRESS)
268 fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
269 fdset = (fd_set *)xmalloc(fdsetsz);
271 memset(fdset, 0, fdsetsz);
272 FD_SET(sockfd, fdset);
277 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
278 if (rc != -1 || errno != EINTR)
289 debug("select: %s", strerror(errno));
292 /* Completed or failed */
294 optlen = sizeof(optval);
295 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
297 debug("getsockopt: %s", strerror(errno));
305 unset_nonblock(sockfd);
308 /* Should not occur */
309 fatal("Bogus return (%d) from select()", rc);
317 * Opens a TCP/IP connection to the remote server on the given host.
318 * The address of the remote host will be returned in hostaddr.
319 * If port is 0, the default port will be used. If needpriv is true,
320 * a privileged port will be allocated to make the connection.
321 * This requires super-user privileges if needpriv is true.
322 * Connection_attempts specifies the maximum number of tries (one per
323 * second). If proxy_command is non-NULL, it specifies the command (with %h
324 * and %p substituted for host and port, respectively) to use to contact
328 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
329 u_short port, int family, int connection_attempts,
330 int needpriv, const char *proxy_command)
334 int sock = -1, attempt;
335 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
336 struct addrinfo hints, *ai, *aitop;
338 debug2("ssh_connect: needpriv %d", needpriv);
340 /* If a proxy command is given, connect using it. */
341 if (proxy_command != NULL)
342 return ssh_proxy_connect(host, port, proxy_command);
344 /* No proxy command. */
346 memset(&hints, 0, sizeof(hints));
347 hints.ai_family = family;
348 hints.ai_socktype = SOCK_STREAM;
349 snprintf(strport, sizeof strport, "%u", port);
350 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
351 fatal("%s: %.100s: %s", __progname, host,
352 gai_strerror(gaierr));
355 * Try to connect several times. On some machines, the first time
356 * will sometimes fail. In general socket code appears to behave
357 * quite magically on many machines.
359 for (attempt = 0; ;) {
361 debug("Trying again...");
363 /* Loop through addresses for this host, and try each one in
364 sequence until the connection succeeds. */
365 for (ai = aitop; ai; ai = ai->ai_next) {
366 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
368 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
369 ntop, sizeof(ntop), strport, sizeof(strport),
370 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
371 error("ssh_connect: getnameinfo failed");
374 debug("Connecting to %.200s [%.100s] port %s.",
375 host, ntop, strport);
377 /* Create a socket for connecting. */
378 sock = ssh_create_socket(needpriv, ai);
380 /* Any error is already output */
383 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
384 options.connection_timeout) >= 0) {
385 /* Successful connection. */
386 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
389 debug("connect to address %s port %s: %s",
390 ntop, strport, strerror(errno));
392 * Close the failed socket; there appear to
393 * be some problems when reusing a socket for
394 * which connect() has already returned an
401 break; /* Successful connection. */
404 if (attempt >= connection_attempts)
406 /* Sleep a moment before retrying. */
412 /* Return failure if we didn't get a successful connection. */
413 if (attempt >= connection_attempts) {
414 error("ssh: connect to host %s port %s: %s",
415 host, strport, strerror(errno));
419 debug("Connection established.");
421 /* Set SO_KEEPALIVE if requested. */
422 if (options.tcp_keep_alive &&
423 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
425 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
427 /* Set the connection. */
428 packet_set_connection(sock, sock);
434 * Waits for the server identification string, and sends our own
435 * identification string.
438 ssh_exchange_identification(void)
440 char buf[256], remote_version[256]; /* must be same size! */
441 int remote_major, remote_minor, mismatch;
442 int connection_in = packet_get_connection_in();
443 int connection_out = packet_get_connection_out();
444 int minor1 = PROTOCOL_MINOR_1;
447 /* Read other side's version identification. */
449 for (i = 0; i < sizeof(buf) - 1; i++) {
450 size_t len = atomicio(read, connection_in, &buf[i], 1);
452 if (len != 1 && errno == EPIPE)
453 fatal("ssh_exchange_identification: Connection closed by remote host");
455 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
456 if (buf[i] == '\r') {
459 continue; /**XXX wait for \n */
461 if (buf[i] == '\n') {
466 buf[sizeof(buf) - 1] = 0;
467 if (strncmp(buf, "SSH-", 4) == 0)
469 debug("ssh_exchange_identification: %s", buf);
471 server_version_string = xstrdup(buf);
474 * Check that the versions match. In future this might accept
475 * several versions and set appropriate flags to handle them.
477 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
478 &remote_major, &remote_minor, remote_version) != 3)
479 fatal("Bad remote protocol version identification: '%.100s'", buf);
480 debug("Remote protocol version %d.%d, remote software version %.100s",
481 remote_major, remote_minor, remote_version);
483 compat_datafellows(remote_version);
486 switch (remote_major) {
488 if (remote_minor == 99 &&
489 (options.protocol & SSH_PROTO_2) &&
490 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
494 if (!(options.protocol & SSH_PROTO_1)) {
498 if (remote_minor < 3) {
499 fatal("Remote machine has too old SSH software version.");
500 } else if (remote_minor == 3 || remote_minor == 4) {
501 /* We speak 1.3, too. */
504 if (options.forward_agent) {
505 logit("Agent forwarding disabled for protocol 1.3");
506 options.forward_agent = 0;
511 if (options.protocol & SSH_PROTO_2) {
521 fatal("Protocol major versions differ: %d vs. %d",
522 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
524 /* Send our own protocol version identification. */
525 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
526 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
527 compat20 ? PROTOCOL_MINOR_2 : minor1,
529 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
530 fatal("write: %.100s", strerror(errno));
531 client_version_string = xstrdup(buf);
532 chop(client_version_string);
533 chop(server_version_string);
534 debug("Local version string %.100s", client_version_string);
537 /* defaults to 'no' */
539 confirm(const char *prompt)
541 const char *msg, *again = "Please type 'yes' or 'no': ";
545 if (options.batch_mode)
547 for (msg = prompt;;msg = again) {
548 p = read_passphrase(msg, RP_ECHO);
550 (p[0] == '\0') || (p[0] == '\n') ||
551 strncasecmp(p, "no", 2) == 0)
553 if (p && strncasecmp(p, "yes", 3) == 0)
563 * check whether the supplied host key is valid, return -1 if the key
564 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
567 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
568 int readonly, const char *user_hostfile, const char *system_hostfile)
571 const char *type = key_type(host_key);
573 char hostline[1000], *hostp, *fp;
574 HostStatus host_status;
575 HostStatus ip_status;
576 int r, local = 0, host_ip_differ = 0;
578 char ntop[NI_MAXHOST];
580 int len, host_line, ip_line;
581 const char *host_file = NULL, *ip_file = NULL;
584 * Force accepting of the host key for loopback/localhost. The
585 * problem is that if the home directory is NFS-mounted to multiple
586 * machines, localhost will refer to a different machine in each of
587 * them, and the user will get bogus HOST_CHANGED warnings. This
588 * essentially disables host authentication for localhost; however,
589 * this is probably not a real problem.
591 /** hostaddr == 0! */
592 switch (hostaddr->sa_family) {
594 local = (ntohl(((struct sockaddr_in *)hostaddr)->
595 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
596 salen = sizeof(struct sockaddr_in);
599 local = IN6_IS_ADDR_LOOPBACK(
600 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
601 salen = sizeof(struct sockaddr_in6);
605 salen = sizeof(struct sockaddr_storage);
608 if (options.no_host_authentication_for_localhost == 1 && local &&
609 options.host_key_alias == NULL) {
610 debug("Forcing accepting of host key for "
611 "loopback/localhost.");
616 * We don't have the remote ip-address for connections
617 * using a proxy command
619 if (options.proxy_command == NULL) {
620 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
621 NULL, 0, NI_NUMERICHOST) != 0)
622 fatal("check_host_key: getnameinfo failed");
625 ip = xstrdup("<no hostip for proxy command>");
628 * Turn off check_host_ip if the connection is to localhost, via proxy
629 * command or if we don't have a hostname to compare with
631 if (options.check_host_ip &&
632 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
633 options.check_host_ip = 0;
636 * Allow the user to record the key under a different name. This is
637 * useful for ssh tunneling over forwarded connections or if you run
638 * multiple sshd's on different ports on the same machine.
640 if (options.host_key_alias != NULL) {
641 host = options.host_key_alias;
642 debug("using hostkeyalias: %s", host);
646 * Store the host key from the known host file in here so that we can
647 * compare it with the key for the IP address.
649 file_key = key_new(host_key->type);
652 * Check if the host key is present in the user\'s list of known
653 * hosts or in the systemwide list.
655 host_file = user_hostfile;
656 host_status = check_host_in_hostfile(host_file, host, host_key,
657 file_key, &host_line);
658 if (host_status == HOST_NEW) {
659 host_file = system_hostfile;
660 host_status = check_host_in_hostfile(host_file, host, host_key,
661 file_key, &host_line);
664 * Also perform check for the ip address, skip the check if we are
665 * localhost or the hostname was an ip address to begin with
667 if (options.check_host_ip) {
668 Key *ip_key = key_new(host_key->type);
670 ip_file = user_hostfile;
671 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
673 if (ip_status == HOST_NEW) {
674 ip_file = system_hostfile;
675 ip_status = check_host_in_hostfile(ip_file, ip,
676 host_key, ip_key, &ip_line);
678 if (host_status == HOST_CHANGED &&
679 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
684 ip_status = host_status;
688 switch (host_status) {
690 /* The host is known and the key matches. */
691 debug("Host '%.200s' is known and matches the %s host key.",
693 debug("Found key in %s:%d", host_file, host_line);
694 if (options.check_host_ip && ip_status == HOST_NEW) {
696 logit("%s host key for IP address "
697 "'%.128s' not in list of known hosts.",
699 else if (!add_host_to_hostfile(user_hostfile, ip,
700 host_key, options.hash_known_hosts))
701 logit("Failed to add the %s host key for IP "
702 "address '%.128s' to the list of known "
703 "hosts (%.30s).", type, ip, user_hostfile);
705 logit("Warning: Permanently added the %s host "
706 "key for IP address '%.128s' to the list "
707 "of known hosts.", type, ip);
713 /* The host is new. */
714 if (options.strict_host_key_checking == 1) {
716 * User has requested strict host key checking. We
717 * will not add the host key automatically. The only
718 * alternative left is to abort.
720 error("No %s host key is known for %.200s and you "
721 "have requested strict checking.", type, host);
723 } else if (options.strict_host_key_checking == 2) {
724 char msg1[1024], msg2[1024];
726 if (show_other_keys(host, host_key))
727 snprintf(msg1, sizeof(msg1),
728 "\nbut keys of different type are already"
729 " known for this host.");
731 snprintf(msg1, sizeof(msg1), ".");
733 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
735 if (options.verify_host_key_dns) {
736 if (matching_host_key_dns)
737 snprintf(msg2, sizeof(msg2),
738 "Matching host key fingerprint"
741 snprintf(msg2, sizeof(msg2),
742 "No matching host key fingerprint"
745 snprintf(msg, sizeof(msg),
746 "The authenticity of host '%.200s (%s)' can't be "
748 "%s key fingerprint is %s.\n%s"
749 "Are you sure you want to continue connecting "
751 host, ip, msg1, type, fp, msg2);
757 * If not in strict mode, add the key automatically to the
758 * local known_hosts file.
760 if (options.check_host_ip && ip_status == HOST_NEW) {
761 snprintf(hostline, sizeof(hostline), "%s,%s",
764 if (options.hash_known_hosts) {
765 /* Add hash of host and IP separately */
766 r = add_host_to_hostfile(user_hostfile, host,
767 host_key, options.hash_known_hosts) &&
768 add_host_to_hostfile(user_hostfile, ip,
769 host_key, options.hash_known_hosts);
771 /* Add unhashed "host,ip" */
772 r = add_host_to_hostfile(user_hostfile,
774 options.hash_known_hosts);
777 r = add_host_to_hostfile(user_hostfile, host, host_key,
778 options.hash_known_hosts);
783 logit("Failed to add the host to the list of known "
784 "hosts (%.500s).", user_hostfile);
786 logit("Warning: Permanently added '%.200s' (%s) to the "
787 "list of known hosts.", hostp, type);
790 if (options.check_host_ip && host_ip_differ) {
792 if (ip_status == HOST_NEW)
793 key_msg = "is unknown";
794 else if (ip_status == HOST_OK)
795 key_msg = "is unchanged";
797 key_msg = "has a different value";
798 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
799 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
800 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
801 error("The %s host key for %s has changed,", type, host);
802 error("and the key for the according IP address %s", ip);
803 error("%s. This could either mean that", key_msg);
804 error("DNS SPOOFING is happening or the IP address for the host");
805 error("and its host key have changed at the same time.");
806 if (ip_status != HOST_NEW)
807 error("Offending key for IP in %s:%d", ip_file, ip_line);
809 /* The host key has changed. */
810 warn_changed_key(host_key);
811 error("Add correct host key in %.100s to get rid of this message.",
813 error("Offending key in %s:%d", host_file, host_line);
816 * If strict host key checking is in use, the user will have
817 * to edit the key manually and we can only abort.
819 if (options.strict_host_key_checking) {
820 error("%s host key for %.200s has changed and you have "
821 "requested strict checking.", type, host);
826 * If strict host key checking has not been requested, allow
827 * the connection but without MITM-able authentication or
830 if (options.password_authentication) {
831 error("Password authentication is disabled to avoid "
832 "man-in-the-middle attacks.");
833 options.password_authentication = 0;
835 if (options.kbd_interactive_authentication) {
836 error("Keyboard-interactive authentication is disabled"
837 " to avoid man-in-the-middle attacks.");
838 options.kbd_interactive_authentication = 0;
839 options.challenge_response_authentication = 0;
841 if (options.challenge_response_authentication) {
842 error("Challenge/response authentication is disabled"
843 " to avoid man-in-the-middle attacks.");
844 options.challenge_response_authentication = 0;
846 if (options.forward_agent) {
847 error("Agent forwarding is disabled to avoid "
848 "man-in-the-middle attacks.");
849 options.forward_agent = 0;
851 if (options.forward_x11) {
852 error("X11 forwarding is disabled to avoid "
853 "man-in-the-middle attacks.");
854 options.forward_x11 = 0;
856 if (options.num_local_forwards > 0 ||
857 options.num_remote_forwards > 0) {
858 error("Port forwarding is disabled to avoid "
859 "man-in-the-middle attacks.");
860 options.num_local_forwards =
861 options.num_remote_forwards = 0;
864 * XXX Should permit the user to change to use the new id.
865 * This could be done by converting the host key to an
866 * identifying sentence, tell that the host identifies itself
867 * by that sentence, and ask the user if he/she whishes to
868 * accept the authentication.
872 fatal("internal error");
876 if (options.check_host_ip && host_status != HOST_CHANGED &&
877 ip_status == HOST_CHANGED) {
878 snprintf(msg, sizeof(msg),
879 "Warning: the %s host key for '%.200s' "
880 "differs from the key for the IP address '%.128s'"
881 "\nOffending key for IP in %s:%d",
882 type, host, ip, ip_file, ip_line);
883 if (host_status == HOST_OK) {
885 snprintf(msg + len, sizeof(msg) - len,
886 "\nMatching host key in %s:%d",
887 host_file, host_line);
889 if (options.strict_host_key_checking == 1) {
891 error("Exiting, you have requested strict checking.");
893 } else if (options.strict_host_key_checking == 2) {
894 strlcat(msg, "\nAre you sure you want "
895 "to continue connecting (yes/no)? ", sizeof(msg));
911 /* returns 0 if key verifies or -1 if key does NOT verify */
913 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
918 if (options.verify_host_key_dns &&
919 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
921 if (flags & DNS_VERIFY_FOUND) {
923 if (options.verify_host_key_dns == 1 &&
924 flags & DNS_VERIFY_MATCH &&
925 flags & DNS_VERIFY_SECURE)
928 if (flags & DNS_VERIFY_MATCH) {
929 matching_host_key_dns = 1;
931 warn_changed_key(host_key);
932 error("Update the SSHFP RR in DNS with the new "
933 "host key to get rid of this message.");
938 /* return ok if the key can be found in an old keyfile */
939 if (stat(options.system_hostfile2, &st) == 0 ||
940 stat(options.user_hostfile2, &st) == 0) {
941 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
942 options.user_hostfile2, options.system_hostfile2) == 0)
945 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
946 options.user_hostfile, options.system_hostfile);
950 * Starts a dialog with the server, and authenticates the current user on the
951 * server. This does not need any extra privileges. The basic connection
952 * to the server must already have been established before this is called.
953 * If login fails, this function prints an error and never returns.
954 * This function does not require super-user privileges.
957 ssh_login(Sensitive *sensitive, const char *orighost,
958 struct sockaddr *hostaddr, struct passwd *pw)
961 char *server_user, *local_user;
963 local_user = xstrdup(pw->pw_name);
964 server_user = options.user ? options.user : local_user;
966 /* Convert the user-supplied hostname into all lowercase. */
967 host = xstrdup(orighost);
968 for (cp = host; *cp; cp++)
972 /* Exchange protocol version identification strings with the server. */
973 ssh_exchange_identification();
975 /* Put the connection into non-blocking mode. */
976 packet_set_nonblocking();
979 /* authenticate user */
981 ssh_kex2(host, hostaddr);
982 ssh_userauth2(local_user, server_user, host, sensitive);
984 ssh_kex(host, hostaddr);
985 ssh_userauth1(local_user, server_user, host, sensitive);
990 ssh_put_password(char *password)
995 if (datafellows & SSH_BUG_PASSWORDPAD) {
996 packet_put_cstring(password);
999 size = roundup(strlen(password) + 1, 32);
1000 padded = xmalloc(size);
1001 memset(padded, 0, size);
1002 strlcpy(padded, password, size);
1003 packet_put_string(padded, size);
1004 memset(padded, 0, size);
1009 show_key_from_file(const char *file, const char *host, int keytype)
1015 found = key_new(keytype);
1016 if ((ret = lookup_key_in_hostfile_by_type(file, host,
1017 keytype, found, &line))) {
1018 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1019 logit("WARNING: %s key found for host %s\n"
1021 "%s key fingerprint %s.",
1022 key_type(found), host, file, line,
1023 key_type(found), fp);
1030 /* print all known host keys for a given host, but skip keys of given type */
1032 show_other_keys(const char *host, Key *key)
1034 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1037 for (i = 0; type[i] != -1; i++) {
1038 if (type[i] == key->type)
1040 if (type[i] != KEY_RSA1 &&
1041 show_key_from_file(options.user_hostfile2, host, type[i])) {
1045 if (type[i] != KEY_RSA1 &&
1046 show_key_from_file(options.system_hostfile2, host, type[i])) {
1050 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1054 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1058 debug2("no key of type %d for host %s", type[i], host);
1064 warn_changed_key(Key *host_key)
1067 const char *type = key_type(host_key);
1069 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1071 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1072 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1073 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1074 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1075 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1076 error("It is also possible that the %s host key has just been changed.", type);
1077 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1079 error("Please contact your system administrator.");