1 /* $OpenBSD: sshconnect.c,v 1.198 2006/08/01 23:22:47 stevesk 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>
48 #include "sshconnect.h"
57 char *client_version_string = NULL;
58 char *server_version_string = NULL;
60 static int matching_host_key_dns = 0;
63 extern Options options;
64 extern char *__progname;
65 extern uid_t original_real_uid;
66 extern uid_t original_effective_uid;
67 extern pid_t proxy_command_pid;
69 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
70 #define INET6_ADDRSTRLEN 46
73 static int show_other_keys(const char *, Key *);
74 static void warn_changed_key(Key *);
77 * Connect to the given ssh server using a proxy command.
80 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
82 char *command_string, *tmp;
85 char strport[NI_MAXSERV];
87 /* Convert the port number into a string. */
88 snprintf(strport, sizeof strport, "%hu", port);
91 * Build the final command string in the buffer by making the
92 * appropriate substitutions to the given proxy command.
94 * Use "exec" to avoid "sh -c" processes on some platforms
97 xasprintf(&tmp, "exec %s", proxy_command);
98 command_string = percent_expand(tmp, "h", host,
99 "p", strport, (char *)NULL);
102 /* Create pipes for communicating with the proxy. */
103 if (pipe(pin) < 0 || pipe(pout) < 0)
104 fatal("Could not create pipes to communicate with the proxy: %.100s",
107 debug("Executing proxy command: %.500s", command_string);
109 /* Fork and execute the proxy command. */
110 if ((pid = fork()) == 0) {
113 /* Child. Permanently give up superuser privileges. */
114 permanently_drop_suid(original_real_uid);
116 /* Redirect stdin and stdout. */
119 if (dup2(pin[0], 0) < 0)
120 perror("dup2 stdin");
124 if (dup2(pout[1], 1) < 0)
125 perror("dup2 stdout");
126 /* Cannot be 1 because pin allocated two descriptors. */
129 /* Stderr is left as it is so that error messages get
130 printed on the user's terminal. */
131 argv[0] = _PATH_BSHELL;
133 argv[2] = command_string;
136 /* Execute the proxy command. Note that we gave up any
137 extra privileges above. */
138 execv(argv[0], argv);
144 fatal("fork failed: %.100s", strerror(errno));
146 proxy_command_pid = pid; /* save pid to clean up later */
148 /* Close child side of the descriptors. */
152 /* Free the command name. */
153 xfree(command_string);
155 /* Set the connection file descriptors. */
156 packet_set_connection(pout[0], pin[1]);
158 /* Indicate OK return */
163 * Creates a (possibly privileged) socket for use as the ssh connection.
166 ssh_create_socket(int privileged, struct addrinfo *ai)
169 struct addrinfo hints, *res;
172 * If we are running as root and want to connect to a privileged
173 * port, bind our own socket to a privileged port.
176 int p = IPPORT_RESERVED - 1;
178 sock = rresvport_af(&p, ai->ai_family);
181 error("rresvport: af=%d %.100s", ai->ai_family,
184 debug("Allocated local port %d.", p);
187 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
189 error("socket: %.100s", strerror(errno));
191 /* Bind the socket to an alternative local IP address */
192 if (options.bind_address == NULL)
195 memset(&hints, 0, sizeof(hints));
196 hints.ai_family = ai->ai_family;
197 hints.ai_socktype = ai->ai_socktype;
198 hints.ai_protocol = ai->ai_protocol;
199 hints.ai_flags = AI_PASSIVE;
200 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
202 error("getaddrinfo: %s: %s", options.bind_address,
203 gai_strerror(gaierr));
207 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
208 error("bind: %s: %s", options.bind_address, strerror(errno));
218 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
219 socklen_t addrlen, int timeout)
224 int optval, rc, result = -1;
227 return (connect(sockfd, serv_addr, addrlen));
229 set_nonblock(sockfd);
230 rc = connect(sockfd, serv_addr, addrlen);
232 unset_nonblock(sockfd);
235 if (errno != EINPROGRESS)
238 fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
240 FD_SET(sockfd, fdset);
245 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
246 if (rc != -1 || errno != EINTR)
257 debug("select: %s", strerror(errno));
260 /* Completed or failed */
262 optlen = sizeof(optval);
263 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
265 debug("getsockopt: %s", strerror(errno));
273 unset_nonblock(sockfd);
276 /* Should not occur */
277 fatal("Bogus return (%d) from select()", rc);
285 * Opens a TCP/IP connection to the remote server on the given host.
286 * The address of the remote host will be returned in hostaddr.
287 * If port is 0, the default port will be used. If needpriv is true,
288 * a privileged port will be allocated to make the connection.
289 * This requires super-user privileges if needpriv is true.
290 * Connection_attempts specifies the maximum number of tries (one per
291 * second). If proxy_command is non-NULL, it specifies the command (with %h
292 * and %p substituted for host and port, respectively) to use to contact
296 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
297 u_short port, int family, int connection_attempts,
298 int needpriv, const char *proxy_command)
302 int sock = -1, attempt;
303 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
304 struct addrinfo hints, *ai, *aitop;
306 debug2("ssh_connect: needpriv %d", needpriv);
308 /* If a proxy command is given, connect using it. */
309 if (proxy_command != NULL)
310 return ssh_proxy_connect(host, port, proxy_command);
312 /* No proxy command. */
314 memset(&hints, 0, sizeof(hints));
315 hints.ai_family = family;
316 hints.ai_socktype = SOCK_STREAM;
317 snprintf(strport, sizeof strport, "%u", port);
318 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
319 fatal("%s: %.100s: %s", __progname, host,
320 gai_strerror(gaierr));
322 for (attempt = 0; attempt < connection_attempts; attempt++) {
324 debug("Trying again...");
327 * Loop through addresses for this host, and try each one in
328 * sequence until the connection succeeds.
330 for (ai = aitop; ai; ai = ai->ai_next) {
331 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
333 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
334 ntop, sizeof(ntop), strport, sizeof(strport),
335 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
336 error("ssh_connect: getnameinfo failed");
339 debug("Connecting to %.200s [%.100s] port %s.",
340 host, ntop, strport);
342 /* Create a socket for connecting. */
343 sock = ssh_create_socket(needpriv, ai);
345 /* Any error is already output */
348 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
349 options.connection_timeout) >= 0) {
350 /* Successful connection. */
351 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
354 debug("connect to address %s port %s: %s",
355 ntop, strport, strerror(errno));
361 break; /* Successful connection. */
363 /* Sleep a moment before retrying. */
369 /* Return failure if we didn't get a successful connection. */
371 error("ssh: connect to host %s port %s: %s",
372 host, strport, strerror(errno));
376 debug("Connection established.");
378 /* Set SO_KEEPALIVE if requested. */
379 if (options.tcp_keep_alive &&
380 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
382 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
384 /* Set the connection. */
385 packet_set_connection(sock, sock);
391 * Waits for the server identification string, and sends our own
392 * identification string.
395 ssh_exchange_identification(void)
397 char buf[256], remote_version[256]; /* must be same size! */
398 int remote_major, remote_minor, mismatch;
399 int connection_in = packet_get_connection_in();
400 int connection_out = packet_get_connection_out();
401 int minor1 = PROTOCOL_MINOR_1;
404 /* Read other side's version identification. */
406 for (i = 0; i < sizeof(buf) - 1; i++) {
407 size_t len = atomicio(read, connection_in, &buf[i], 1);
409 if (len != 1 && errno == EPIPE)
410 fatal("ssh_exchange_identification: Connection closed by remote host");
412 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
413 if (buf[i] == '\r') {
416 continue; /**XXX wait for \n */
418 if (buf[i] == '\n') {
423 fatal("ssh_exchange_identification: No banner received");
425 buf[sizeof(buf) - 1] = 0;
426 if (strncmp(buf, "SSH-", 4) == 0)
428 debug("ssh_exchange_identification: %s", buf);
430 server_version_string = xstrdup(buf);
433 * Check that the versions match. In future this might accept
434 * several versions and set appropriate flags to handle them.
436 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
437 &remote_major, &remote_minor, remote_version) != 3)
438 fatal("Bad remote protocol version identification: '%.100s'", buf);
439 debug("Remote protocol version %d.%d, remote software version %.100s",
440 remote_major, remote_minor, remote_version);
442 compat_datafellows(remote_version);
445 switch (remote_major) {
447 if (remote_minor == 99 &&
448 (options.protocol & SSH_PROTO_2) &&
449 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
453 if (!(options.protocol & SSH_PROTO_1)) {
457 if (remote_minor < 3) {
458 fatal("Remote machine has too old SSH software version.");
459 } else if (remote_minor == 3 || remote_minor == 4) {
460 /* We speak 1.3, too. */
463 if (options.forward_agent) {
464 logit("Agent forwarding disabled for protocol 1.3");
465 options.forward_agent = 0;
470 if (options.protocol & SSH_PROTO_2) {
480 fatal("Protocol major versions differ: %d vs. %d",
481 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
483 /* Send our own protocol version identification. */
484 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
485 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
486 compat20 ? PROTOCOL_MINOR_2 : minor1,
488 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
489 fatal("write: %.100s", strerror(errno));
490 client_version_string = xstrdup(buf);
491 chop(client_version_string);
492 chop(server_version_string);
493 debug("Local version string %.100s", client_version_string);
496 /* defaults to 'no' */
498 confirm(const char *prompt)
500 const char *msg, *again = "Please type 'yes' or 'no': ";
504 if (options.batch_mode)
506 for (msg = prompt;;msg = again) {
507 p = read_passphrase(msg, RP_ECHO);
509 (p[0] == '\0') || (p[0] == '\n') ||
510 strncasecmp(p, "no", 2) == 0)
512 if (p && strncasecmp(p, "yes", 3) == 0)
522 * check whether the supplied host key is valid, return -1 if the key
523 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
529 check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
530 Key *host_key, int readonly, const char *user_hostfile,
531 const char *system_hostfile)
534 const char *type = key_type(host_key);
535 char *ip = NULL, *host = NULL;
536 char hostline[1000], *hostp, *fp;
537 HostStatus host_status;
538 HostStatus ip_status;
539 int r, local = 0, host_ip_differ = 0;
541 char ntop[NI_MAXHOST];
543 int len, host_line, ip_line;
544 const char *host_file = NULL, *ip_file = NULL;
547 * Force accepting of the host key for loopback/localhost. The
548 * problem is that if the home directory is NFS-mounted to multiple
549 * machines, localhost will refer to a different machine in each of
550 * them, and the user will get bogus HOST_CHANGED warnings. This
551 * essentially disables host authentication for localhost; however,
552 * this is probably not a real problem.
554 /** hostaddr == 0! */
555 switch (hostaddr->sa_family) {
557 local = (ntohl(((struct sockaddr_in *)hostaddr)->
558 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
559 salen = sizeof(struct sockaddr_in);
562 local = IN6_IS_ADDR_LOOPBACK(
563 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
564 salen = sizeof(struct sockaddr_in6);
568 salen = sizeof(struct sockaddr_storage);
571 if (options.no_host_authentication_for_localhost == 1 && local &&
572 options.host_key_alias == NULL) {
573 debug("Forcing accepting of host key for "
574 "loopback/localhost.");
579 * We don't have the remote ip-address for connections
580 * using a proxy command
582 if (options.proxy_command == NULL) {
583 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
584 NULL, 0, NI_NUMERICHOST) != 0)
585 fatal("check_host_key: getnameinfo failed");
586 ip = put_host_port(ntop, port);
588 ip = xstrdup("<no hostip for proxy command>");
591 * Turn off check_host_ip if the connection is to localhost, via proxy
592 * command or if we don't have a hostname to compare with
594 if (options.check_host_ip && (local ||
595 strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
596 options.check_host_ip = 0;
599 * Allow the user to record the key under a different name or
600 * differentiate a non-standard port. This is useful for ssh
601 * tunneling over forwarded connections or if you run multiple
602 * sshd's on different ports on the same machine.
604 if (options.host_key_alias != NULL) {
605 host = xstrdup(options.host_key_alias);
606 debug("using hostkeyalias: %s", host);
608 host = put_host_port(hostname, port);
612 * Store the host key from the known host file in here so that we can
613 * compare it with the key for the IP address.
615 file_key = key_new(host_key->type);
618 * Check if the host key is present in the user's list of known
619 * hosts or in the systemwide list.
621 host_file = user_hostfile;
622 host_status = check_host_in_hostfile(host_file, host, host_key,
623 file_key, &host_line);
624 if (host_status == HOST_NEW) {
625 host_file = system_hostfile;
626 host_status = check_host_in_hostfile(host_file, host, host_key,
627 file_key, &host_line);
630 * Also perform check for the ip address, skip the check if we are
631 * localhost or the hostname was an ip address to begin with
633 if (options.check_host_ip) {
634 Key *ip_key = key_new(host_key->type);
636 ip_file = user_hostfile;
637 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
639 if (ip_status == HOST_NEW) {
640 ip_file = system_hostfile;
641 ip_status = check_host_in_hostfile(ip_file, ip,
642 host_key, ip_key, &ip_line);
644 if (host_status == HOST_CHANGED &&
645 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
650 ip_status = host_status;
654 switch (host_status) {
656 /* The host is known and the key matches. */
657 debug("Host '%.200s' is known and matches the %s host key.",
659 debug("Found key in %s:%d", host_file, host_line);
660 if (options.check_host_ip && ip_status == HOST_NEW) {
662 logit("%s host key for IP address "
663 "'%.128s' not in list of known hosts.",
665 else if (!add_host_to_hostfile(user_hostfile, ip,
666 host_key, options.hash_known_hosts))
667 logit("Failed to add the %s host key for IP "
668 "address '%.128s' to the list of known "
669 "hosts (%.30s).", type, ip, user_hostfile);
671 logit("Warning: Permanently added the %s host "
672 "key for IP address '%.128s' to the list "
673 "of known hosts.", type, ip);
677 if (options.host_key_alias == NULL && port != 0 &&
678 port != SSH_DEFAULT_PORT) {
679 debug("checking without port identifier");
680 if (check_host_key(hostname, hostaddr, 0, host_key, 2,
681 user_hostfile, system_hostfile) == 0) {
682 debug("found matching key w/out port");
688 /* The host is new. */
689 if (options.strict_host_key_checking == 1) {
691 * User has requested strict host key checking. We
692 * will not add the host key automatically. The only
693 * alternative left is to abort.
695 error("No %s host key is known for %.200s and you "
696 "have requested strict checking.", type, host);
698 } else if (options.strict_host_key_checking == 2) {
699 char msg1[1024], msg2[1024];
701 if (show_other_keys(host, host_key))
702 snprintf(msg1, sizeof(msg1),
703 "\nbut keys of different type are already"
704 " known for this host.");
706 snprintf(msg1, sizeof(msg1), ".");
708 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
710 if (options.verify_host_key_dns) {
711 if (matching_host_key_dns)
712 snprintf(msg2, sizeof(msg2),
713 "Matching host key fingerprint"
716 snprintf(msg2, sizeof(msg2),
717 "No matching host key fingerprint"
720 snprintf(msg, sizeof(msg),
721 "The authenticity of host '%.200s (%s)' can't be "
723 "%s key fingerprint is %s.\n%s"
724 "Are you sure you want to continue connecting "
726 host, ip, msg1, type, fp, msg2);
732 * If not in strict mode, add the key automatically to the
733 * local known_hosts file.
735 if (options.check_host_ip && ip_status == HOST_NEW) {
736 snprintf(hostline, sizeof(hostline), "%s,%s",
739 if (options.hash_known_hosts) {
740 /* Add hash of host and IP separately */
741 r = add_host_to_hostfile(user_hostfile, host,
742 host_key, options.hash_known_hosts) &&
743 add_host_to_hostfile(user_hostfile, ip,
744 host_key, options.hash_known_hosts);
746 /* Add unhashed "host,ip" */
747 r = add_host_to_hostfile(user_hostfile,
749 options.hash_known_hosts);
752 r = add_host_to_hostfile(user_hostfile, host, host_key,
753 options.hash_known_hosts);
758 logit("Failed to add the host to the list of known "
759 "hosts (%.500s).", user_hostfile);
761 logit("Warning: Permanently added '%.200s' (%s) to the "
762 "list of known hosts.", hostp, type);
765 if (readonly == ROQUIET)
767 if (options.check_host_ip && host_ip_differ) {
769 if (ip_status == HOST_NEW)
770 key_msg = "is unknown";
771 else if (ip_status == HOST_OK)
772 key_msg = "is unchanged";
774 key_msg = "has a different value";
775 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
776 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
777 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
778 error("The %s host key for %s has changed,", type, host);
779 error("and the key for the according IP address %s", ip);
780 error("%s. This could either mean that", key_msg);
781 error("DNS SPOOFING is happening or the IP address for the host");
782 error("and its host key have changed at the same time.");
783 if (ip_status != HOST_NEW)
784 error("Offending key for IP in %s:%d", ip_file, ip_line);
786 /* The host key has changed. */
787 warn_changed_key(host_key);
788 error("Add correct host key in %.100s to get rid of this message.",
790 error("Offending key in %s:%d", host_file, host_line);
793 * If strict host key checking is in use, the user will have
794 * to edit the key manually and we can only abort.
796 if (options.strict_host_key_checking) {
797 error("%s host key for %.200s has changed and you have "
798 "requested strict checking.", type, host);
803 * If strict host key checking has not been requested, allow
804 * the connection but without MITM-able authentication or
807 if (options.password_authentication) {
808 error("Password authentication is disabled to avoid "
809 "man-in-the-middle attacks.");
810 options.password_authentication = 0;
812 if (options.kbd_interactive_authentication) {
813 error("Keyboard-interactive authentication is disabled"
814 " to avoid man-in-the-middle attacks.");
815 options.kbd_interactive_authentication = 0;
816 options.challenge_response_authentication = 0;
818 if (options.challenge_response_authentication) {
819 error("Challenge/response authentication is disabled"
820 " to avoid man-in-the-middle attacks.");
821 options.challenge_response_authentication = 0;
823 if (options.forward_agent) {
824 error("Agent forwarding is disabled to avoid "
825 "man-in-the-middle attacks.");
826 options.forward_agent = 0;
828 if (options.forward_x11) {
829 error("X11 forwarding is disabled to avoid "
830 "man-in-the-middle attacks.");
831 options.forward_x11 = 0;
833 if (options.num_local_forwards > 0 ||
834 options.num_remote_forwards > 0) {
835 error("Port forwarding is disabled to avoid "
836 "man-in-the-middle attacks.");
837 options.num_local_forwards =
838 options.num_remote_forwards = 0;
840 if (options.tun_open != SSH_TUNMODE_NO) {
841 error("Tunnel forwarding is disabled to avoid "
842 "man-in-the-middle attacks.");
843 options.tun_open = SSH_TUNMODE_NO;
846 * XXX Should permit the user to change to use the new id.
847 * This could be done by converting the host key to an
848 * identifying sentence, tell that the host identifies itself
849 * by that sentence, and ask the user if he/she whishes to
850 * accept the authentication.
854 fatal("internal error");
858 if (options.check_host_ip && host_status != HOST_CHANGED &&
859 ip_status == HOST_CHANGED) {
860 snprintf(msg, sizeof(msg),
861 "Warning: the %s host key for '%.200s' "
862 "differs from the key for the IP address '%.128s'"
863 "\nOffending key for IP in %s:%d",
864 type, host, ip, ip_file, ip_line);
865 if (host_status == HOST_OK) {
867 snprintf(msg + len, sizeof(msg) - len,
868 "\nMatching host key in %s:%d",
869 host_file, host_line);
871 if (options.strict_host_key_checking == 1) {
873 error("Exiting, you have requested strict checking.");
875 } else if (options.strict_host_key_checking == 2) {
876 strlcat(msg, "\nAre you sure you want "
877 "to continue connecting (yes/no)? ", sizeof(msg));
895 /* returns 0 if key verifies or -1 if key does NOT verify */
897 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
902 if (options.verify_host_key_dns &&
903 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
905 if (flags & DNS_VERIFY_FOUND) {
907 if (options.verify_host_key_dns == 1 &&
908 flags & DNS_VERIFY_MATCH &&
909 flags & DNS_VERIFY_SECURE)
912 if (flags & DNS_VERIFY_MATCH) {
913 matching_host_key_dns = 1;
915 warn_changed_key(host_key);
916 error("Update the SSHFP RR in DNS with the new "
917 "host key to get rid of this message.");
922 /* return ok if the key can be found in an old keyfile */
923 if (stat(options.system_hostfile2, &st) == 0 ||
924 stat(options.user_hostfile2, &st) == 0) {
925 if (check_host_key(host, hostaddr, options.port, host_key,
926 RDONLY, options.user_hostfile2,
927 options.system_hostfile2) == 0)
930 return check_host_key(host, hostaddr, options.port, host_key,
931 RDRW, options.user_hostfile, options.system_hostfile);
935 * Starts a dialog with the server, and authenticates the current user on the
936 * server. This does not need any extra privileges. The basic connection
937 * to the server must already have been established before this is called.
938 * If login fails, this function prints an error and never returns.
939 * This function does not require super-user privileges.
942 ssh_login(Sensitive *sensitive, const char *orighost,
943 struct sockaddr *hostaddr, struct passwd *pw)
946 char *server_user, *local_user;
948 local_user = xstrdup(pw->pw_name);
949 server_user = options.user ? options.user : local_user;
951 /* Convert the user-supplied hostname into all lowercase. */
952 host = xstrdup(orighost);
953 for (cp = host; *cp; cp++)
955 *cp = (char)tolower(*cp);
957 /* Exchange protocol version identification strings with the server. */
958 ssh_exchange_identification();
960 /* Put the connection into non-blocking mode. */
961 packet_set_nonblocking();
964 /* authenticate user */
966 ssh_kex2(host, hostaddr);
967 ssh_userauth2(local_user, server_user, host, sensitive);
969 ssh_kex(host, hostaddr);
970 ssh_userauth1(local_user, server_user, host, sensitive);
976 ssh_put_password(char *password)
981 if (datafellows & SSH_BUG_PASSWORDPAD) {
982 packet_put_cstring(password);
985 size = roundup(strlen(password) + 1, 32);
986 padded = xcalloc(1, size);
987 strlcpy(padded, password, size);
988 packet_put_string(padded, size);
989 memset(padded, 0, size);
994 show_key_from_file(const char *file, const char *host, int keytype)
1000 found = key_new(keytype);
1001 if ((ret = lookup_key_in_hostfile_by_type(file, host,
1002 keytype, found, &line))) {
1003 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1004 logit("WARNING: %s key found for host %s\n"
1006 "%s key fingerprint %s.",
1007 key_type(found), host, file, line,
1008 key_type(found), fp);
1015 /* print all known host keys for a given host, but skip keys of given type */
1017 show_other_keys(const char *host, Key *key)
1019 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1022 for (i = 0; type[i] != -1; i++) {
1023 if (type[i] == key->type)
1025 if (type[i] != KEY_RSA1 &&
1026 show_key_from_file(options.user_hostfile2, host, type[i])) {
1030 if (type[i] != KEY_RSA1 &&
1031 show_key_from_file(options.system_hostfile2, host, type[i])) {
1035 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1039 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1043 debug2("no key of type %d for host %s", type[i], host);
1049 warn_changed_key(Key *host_key)
1052 const char *type = key_type(host_key);
1054 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1056 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1057 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1058 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1059 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1060 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1061 error("It is also possible that the %s host key has just been changed.", type);
1062 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1064 error("Please contact your system administrator.");
1070 * Execute a local command
1073 ssh_local_cmd(const char *args)
1079 if (!options.permit_local_command ||
1080 args == NULL || !*args)
1083 if ((shell = getenv("SHELL")) == NULL)
1084 shell = _PATH_BSHELL;
1088 debug3("Executing %s -c \"%s\"", shell, args);
1089 execl(shell, shell, "-c", args, (char *)NULL);
1090 error("Couldn't execute %s -c \"%s\": %s",
1091 shell, args, strerror(errno));
1093 } else if (pid == -1)
1094 fatal("fork failed: %.100s", strerror(errno));
1095 while (waitpid(pid, &status, 0) == -1)
1097 fatal("Couldn't wait for child: %s", strerror(errno));
1099 if (!WIFEXITED(status))
1102 return (WEXITSTATUS(status));