1 /* $OpenBSD: sshconnect.c,v 1.197 2006/08/01 11:34:36 dtucker 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>
47 #include "sshconnect.h"
56 char *client_version_string = NULL;
57 char *server_version_string = NULL;
59 static int matching_host_key_dns = 0;
62 extern Options options;
63 extern char *__progname;
64 extern uid_t original_real_uid;
65 extern uid_t original_effective_uid;
66 extern pid_t proxy_command_pid;
68 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
69 #define INET6_ADDRSTRLEN 46
72 static int show_other_keys(const char *, Key *);
73 static void warn_changed_key(Key *);
76 * Connect to the given ssh server using a proxy command.
79 ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
81 char *command_string, *tmp;
84 char strport[NI_MAXSERV];
86 /* Convert the port number into a string. */
87 snprintf(strport, sizeof strport, "%hu", port);
90 * Build the final command string in the buffer by making the
91 * appropriate substitutions to the given proxy command.
93 * Use "exec" to avoid "sh -c" processes on some platforms
96 xasprintf(&tmp, "exec %s", proxy_command);
97 command_string = percent_expand(tmp, "h", host,
98 "p", strport, (char *)NULL);
101 /* Create pipes for communicating with the proxy. */
102 if (pipe(pin) < 0 || pipe(pout) < 0)
103 fatal("Could not create pipes to communicate with the proxy: %.100s",
106 debug("Executing proxy command: %.500s", command_string);
108 /* Fork and execute the proxy command. */
109 if ((pid = fork()) == 0) {
112 /* Child. Permanently give up superuser privileges. */
113 permanently_drop_suid(original_real_uid);
115 /* Redirect stdin and stdout. */
118 if (dup2(pin[0], 0) < 0)
119 perror("dup2 stdin");
123 if (dup2(pout[1], 1) < 0)
124 perror("dup2 stdout");
125 /* Cannot be 1 because pin allocated two descriptors. */
128 /* Stderr is left as it is so that error messages get
129 printed on the user's terminal. */
130 argv[0] = _PATH_BSHELL;
132 argv[2] = command_string;
135 /* Execute the proxy command. Note that we gave up any
136 extra privileges above. */
137 execv(argv[0], argv);
143 fatal("fork failed: %.100s", strerror(errno));
145 proxy_command_pid = pid; /* save pid to clean up later */
147 /* Close child side of the descriptors. */
151 /* Free the command name. */
152 xfree(command_string);
154 /* Set the connection file descriptors. */
155 packet_set_connection(pout[0], pin[1]);
157 /* Indicate OK return */
162 * Creates a (possibly privileged) socket for use as the ssh connection.
165 ssh_create_socket(int privileged, struct addrinfo *ai)
168 struct addrinfo hints, *res;
171 * If we are running as root and want to connect to a privileged
172 * port, bind our own socket to a privileged port.
175 int p = IPPORT_RESERVED - 1;
177 sock = rresvport_af(&p, ai->ai_family);
180 error("rresvport: af=%d %.100s", ai->ai_family,
183 debug("Allocated local port %d.", p);
186 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
188 error("socket: %.100s", strerror(errno));
190 /* Bind the socket to an alternative local IP address */
191 if (options.bind_address == NULL)
194 memset(&hints, 0, sizeof(hints));
195 hints.ai_family = ai->ai_family;
196 hints.ai_socktype = ai->ai_socktype;
197 hints.ai_protocol = ai->ai_protocol;
198 hints.ai_flags = AI_PASSIVE;
199 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
201 error("getaddrinfo: %s: %s", options.bind_address,
202 gai_strerror(gaierr));
206 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
207 error("bind: %s: %s", options.bind_address, strerror(errno));
217 timeout_connect(int sockfd, const struct sockaddr *serv_addr,
218 socklen_t addrlen, int timeout)
223 int optval, rc, result = -1;
226 return (connect(sockfd, serv_addr, addrlen));
228 set_nonblock(sockfd);
229 rc = connect(sockfd, serv_addr, addrlen);
231 unset_nonblock(sockfd);
234 if (errno != EINPROGRESS)
237 fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
239 FD_SET(sockfd, fdset);
244 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
245 if (rc != -1 || errno != EINTR)
256 debug("select: %s", strerror(errno));
259 /* Completed or failed */
261 optlen = sizeof(optval);
262 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
264 debug("getsockopt: %s", strerror(errno));
272 unset_nonblock(sockfd);
275 /* Should not occur */
276 fatal("Bogus return (%d) from select()", rc);
284 * Opens a TCP/IP connection to the remote server on the given host.
285 * The address of the remote host will be returned in hostaddr.
286 * If port is 0, the default port will be used. If needpriv is true,
287 * a privileged port will be allocated to make the connection.
288 * This requires super-user privileges if needpriv is true.
289 * Connection_attempts specifies the maximum number of tries (one per
290 * second). If proxy_command is non-NULL, it specifies the command (with %h
291 * and %p substituted for host and port, respectively) to use to contact
295 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
296 u_short port, int family, int connection_attempts,
297 int needpriv, const char *proxy_command)
301 int sock = -1, attempt;
302 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
303 struct addrinfo hints, *ai, *aitop;
305 debug2("ssh_connect: needpriv %d", needpriv);
307 /* If a proxy command is given, connect using it. */
308 if (proxy_command != NULL)
309 return ssh_proxy_connect(host, port, proxy_command);
311 /* No proxy command. */
313 memset(&hints, 0, sizeof(hints));
314 hints.ai_family = family;
315 hints.ai_socktype = SOCK_STREAM;
316 snprintf(strport, sizeof strport, "%u", port);
317 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
318 fatal("%s: %.100s: %s", __progname, host,
319 gai_strerror(gaierr));
321 for (attempt = 0; attempt < connection_attempts; attempt++) {
323 debug("Trying again...");
326 * Loop through addresses for this host, and try each one in
327 * sequence until the connection succeeds.
329 for (ai = aitop; ai; ai = ai->ai_next) {
330 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
332 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
333 ntop, sizeof(ntop), strport, sizeof(strport),
334 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
335 error("ssh_connect: getnameinfo failed");
338 debug("Connecting to %.200s [%.100s] port %s.",
339 host, ntop, strport);
341 /* Create a socket for connecting. */
342 sock = ssh_create_socket(needpriv, ai);
344 /* Any error is already output */
347 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
348 options.connection_timeout) >= 0) {
349 /* Successful connection. */
350 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
353 debug("connect to address %s port %s: %s",
354 ntop, strport, strerror(errno));
360 break; /* Successful connection. */
362 /* Sleep a moment before retrying. */
368 /* Return failure if we didn't get a successful connection. */
370 error("ssh: connect to host %s port %s: %s",
371 host, strport, strerror(errno));
375 debug("Connection established.");
377 /* Set SO_KEEPALIVE if requested. */
378 if (options.tcp_keep_alive &&
379 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
381 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
383 /* Set the connection. */
384 packet_set_connection(sock, sock);
390 * Waits for the server identification string, and sends our own
391 * identification string.
394 ssh_exchange_identification(void)
396 char buf[256], remote_version[256]; /* must be same size! */
397 int remote_major, remote_minor, mismatch;
398 int connection_in = packet_get_connection_in();
399 int connection_out = packet_get_connection_out();
400 int minor1 = PROTOCOL_MINOR_1;
403 /* Read other side's version identification. */
405 for (i = 0; i < sizeof(buf) - 1; i++) {
406 size_t len = atomicio(read, connection_in, &buf[i], 1);
408 if (len != 1 && errno == EPIPE)
409 fatal("ssh_exchange_identification: Connection closed by remote host");
411 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
412 if (buf[i] == '\r') {
415 continue; /**XXX wait for \n */
417 if (buf[i] == '\n') {
422 fatal("ssh_exchange_identification: No banner received");
424 buf[sizeof(buf) - 1] = 0;
425 if (strncmp(buf, "SSH-", 4) == 0)
427 debug("ssh_exchange_identification: %s", buf);
429 server_version_string = xstrdup(buf);
432 * Check that the versions match. In future this might accept
433 * several versions and set appropriate flags to handle them.
435 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
436 &remote_major, &remote_minor, remote_version) != 3)
437 fatal("Bad remote protocol version identification: '%.100s'", buf);
438 debug("Remote protocol version %d.%d, remote software version %.100s",
439 remote_major, remote_minor, remote_version);
441 compat_datafellows(remote_version);
444 switch (remote_major) {
446 if (remote_minor == 99 &&
447 (options.protocol & SSH_PROTO_2) &&
448 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
452 if (!(options.protocol & SSH_PROTO_1)) {
456 if (remote_minor < 3) {
457 fatal("Remote machine has too old SSH software version.");
458 } else if (remote_minor == 3 || remote_minor == 4) {
459 /* We speak 1.3, too. */
462 if (options.forward_agent) {
463 logit("Agent forwarding disabled for protocol 1.3");
464 options.forward_agent = 0;
469 if (options.protocol & SSH_PROTO_2) {
479 fatal("Protocol major versions differ: %d vs. %d",
480 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
482 /* Send our own protocol version identification. */
483 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
484 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
485 compat20 ? PROTOCOL_MINOR_2 : minor1,
487 if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
488 fatal("write: %.100s", strerror(errno));
489 client_version_string = xstrdup(buf);
490 chop(client_version_string);
491 chop(server_version_string);
492 debug("Local version string %.100s", client_version_string);
495 /* defaults to 'no' */
497 confirm(const char *prompt)
499 const char *msg, *again = "Please type 'yes' or 'no': ";
503 if (options.batch_mode)
505 for (msg = prompt;;msg = again) {
506 p = read_passphrase(msg, RP_ECHO);
508 (p[0] == '\0') || (p[0] == '\n') ||
509 strncasecmp(p, "no", 2) == 0)
511 if (p && strncasecmp(p, "yes", 3) == 0)
521 * check whether the supplied host key is valid, return -1 if the key
522 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
528 check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
529 Key *host_key, int readonly, const char *user_hostfile,
530 const char *system_hostfile)
533 const char *type = key_type(host_key);
534 char *ip = NULL, *host = NULL;
535 char hostline[1000], *hostp, *fp;
536 HostStatus host_status;
537 HostStatus ip_status;
538 int r, local = 0, host_ip_differ = 0;
540 char ntop[NI_MAXHOST];
542 int len, host_line, ip_line;
543 const char *host_file = NULL, *ip_file = NULL;
546 * Force accepting of the host key for loopback/localhost. The
547 * problem is that if the home directory is NFS-mounted to multiple
548 * machines, localhost will refer to a different machine in each of
549 * them, and the user will get bogus HOST_CHANGED warnings. This
550 * essentially disables host authentication for localhost; however,
551 * this is probably not a real problem.
553 /** hostaddr == 0! */
554 switch (hostaddr->sa_family) {
556 local = (ntohl(((struct sockaddr_in *)hostaddr)->
557 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
558 salen = sizeof(struct sockaddr_in);
561 local = IN6_IS_ADDR_LOOPBACK(
562 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
563 salen = sizeof(struct sockaddr_in6);
567 salen = sizeof(struct sockaddr_storage);
570 if (options.no_host_authentication_for_localhost == 1 && local &&
571 options.host_key_alias == NULL) {
572 debug("Forcing accepting of host key for "
573 "loopback/localhost.");
578 * We don't have the remote ip-address for connections
579 * using a proxy command
581 if (options.proxy_command == NULL) {
582 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
583 NULL, 0, NI_NUMERICHOST) != 0)
584 fatal("check_host_key: getnameinfo failed");
585 ip = put_host_port(ntop, port);
587 ip = xstrdup("<no hostip for proxy command>");
590 * Turn off check_host_ip if the connection is to localhost, via proxy
591 * command or if we don't have a hostname to compare with
593 if (options.check_host_ip && (local ||
594 strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
595 options.check_host_ip = 0;
598 * Allow the user to record the key under a different name or
599 * differentiate a non-standard port. This is useful for ssh
600 * tunneling over forwarded connections or if you run multiple
601 * sshd's on different ports on the same machine.
603 if (options.host_key_alias != NULL) {
604 host = xstrdup(options.host_key_alias);
605 debug("using hostkeyalias: %s", host);
607 host = put_host_port(hostname, port);
611 * Store the host key from the known host file in here so that we can
612 * compare it with the key for the IP address.
614 file_key = key_new(host_key->type);
617 * Check if the host key is present in the user's list of known
618 * hosts or in the systemwide list.
620 host_file = user_hostfile;
621 host_status = check_host_in_hostfile(host_file, host, host_key,
622 file_key, &host_line);
623 if (host_status == HOST_NEW) {
624 host_file = system_hostfile;
625 host_status = check_host_in_hostfile(host_file, host, host_key,
626 file_key, &host_line);
629 * Also perform check for the ip address, skip the check if we are
630 * localhost or the hostname was an ip address to begin with
632 if (options.check_host_ip) {
633 Key *ip_key = key_new(host_key->type);
635 ip_file = user_hostfile;
636 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
638 if (ip_status == HOST_NEW) {
639 ip_file = system_hostfile;
640 ip_status = check_host_in_hostfile(ip_file, ip,
641 host_key, ip_key, &ip_line);
643 if (host_status == HOST_CHANGED &&
644 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
649 ip_status = host_status;
653 switch (host_status) {
655 /* The host is known and the key matches. */
656 debug("Host '%.200s' is known and matches the %s host key.",
658 debug("Found key in %s:%d", host_file, host_line);
659 if (options.check_host_ip && ip_status == HOST_NEW) {
661 logit("%s host key for IP address "
662 "'%.128s' not in list of known hosts.",
664 else if (!add_host_to_hostfile(user_hostfile, ip,
665 host_key, options.hash_known_hosts))
666 logit("Failed to add the %s host key for IP "
667 "address '%.128s' to the list of known "
668 "hosts (%.30s).", type, ip, user_hostfile);
670 logit("Warning: Permanently added the %s host "
671 "key for IP address '%.128s' to the list "
672 "of known hosts.", type, ip);
676 if (options.host_key_alias == NULL && port != 0 &&
677 port != SSH_DEFAULT_PORT) {
678 debug("checking without port identifier");
679 if (check_host_key(hostname, hostaddr, 0, host_key, 2,
680 user_hostfile, system_hostfile) == 0) {
681 debug("found matching key w/out port");
687 /* The host is new. */
688 if (options.strict_host_key_checking == 1) {
690 * User has requested strict host key checking. We
691 * will not add the host key automatically. The only
692 * alternative left is to abort.
694 error("No %s host key is known for %.200s and you "
695 "have requested strict checking.", type, host);
697 } else if (options.strict_host_key_checking == 2) {
698 char msg1[1024], msg2[1024];
700 if (show_other_keys(host, host_key))
701 snprintf(msg1, sizeof(msg1),
702 "\nbut keys of different type are already"
703 " known for this host.");
705 snprintf(msg1, sizeof(msg1), ".");
707 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
709 if (options.verify_host_key_dns) {
710 if (matching_host_key_dns)
711 snprintf(msg2, sizeof(msg2),
712 "Matching host key fingerprint"
715 snprintf(msg2, sizeof(msg2),
716 "No matching host key fingerprint"
719 snprintf(msg, sizeof(msg),
720 "The authenticity of host '%.200s (%s)' can't be "
722 "%s key fingerprint is %s.\n%s"
723 "Are you sure you want to continue connecting "
725 host, ip, msg1, type, fp, msg2);
731 * If not in strict mode, add the key automatically to the
732 * local known_hosts file.
734 if (options.check_host_ip && ip_status == HOST_NEW) {
735 snprintf(hostline, sizeof(hostline), "%s,%s",
738 if (options.hash_known_hosts) {
739 /* Add hash of host and IP separately */
740 r = add_host_to_hostfile(user_hostfile, host,
741 host_key, options.hash_known_hosts) &&
742 add_host_to_hostfile(user_hostfile, ip,
743 host_key, options.hash_known_hosts);
745 /* Add unhashed "host,ip" */
746 r = add_host_to_hostfile(user_hostfile,
748 options.hash_known_hosts);
751 r = add_host_to_hostfile(user_hostfile, host, host_key,
752 options.hash_known_hosts);
757 logit("Failed to add the host to the list of known "
758 "hosts (%.500s).", user_hostfile);
760 logit("Warning: Permanently added '%.200s' (%s) to the "
761 "list of known hosts.", hostp, type);
764 if (readonly == ROQUIET)
766 if (options.check_host_ip && host_ip_differ) {
768 if (ip_status == HOST_NEW)
769 key_msg = "is unknown";
770 else if (ip_status == HOST_OK)
771 key_msg = "is unchanged";
773 key_msg = "has a different value";
774 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
775 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
776 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
777 error("The %s host key for %s has changed,", type, host);
778 error("and the key for the according IP address %s", ip);
779 error("%s. This could either mean that", key_msg);
780 error("DNS SPOOFING is happening or the IP address for the host");
781 error("and its host key have changed at the same time.");
782 if (ip_status != HOST_NEW)
783 error("Offending key for IP in %s:%d", ip_file, ip_line);
785 /* The host key has changed. */
786 warn_changed_key(host_key);
787 error("Add correct host key in %.100s to get rid of this message.",
789 error("Offending key in %s:%d", host_file, host_line);
792 * If strict host key checking is in use, the user will have
793 * to edit the key manually and we can only abort.
795 if (options.strict_host_key_checking) {
796 error("%s host key for %.200s has changed and you have "
797 "requested strict checking.", type, host);
802 * If strict host key checking has not been requested, allow
803 * the connection but without MITM-able authentication or
806 if (options.password_authentication) {
807 error("Password authentication is disabled to avoid "
808 "man-in-the-middle attacks.");
809 options.password_authentication = 0;
811 if (options.kbd_interactive_authentication) {
812 error("Keyboard-interactive authentication is disabled"
813 " to avoid man-in-the-middle attacks.");
814 options.kbd_interactive_authentication = 0;
815 options.challenge_response_authentication = 0;
817 if (options.challenge_response_authentication) {
818 error("Challenge/response authentication is disabled"
819 " to avoid man-in-the-middle attacks.");
820 options.challenge_response_authentication = 0;
822 if (options.forward_agent) {
823 error("Agent forwarding is disabled to avoid "
824 "man-in-the-middle attacks.");
825 options.forward_agent = 0;
827 if (options.forward_x11) {
828 error("X11 forwarding is disabled to avoid "
829 "man-in-the-middle attacks.");
830 options.forward_x11 = 0;
832 if (options.num_local_forwards > 0 ||
833 options.num_remote_forwards > 0) {
834 error("Port forwarding is disabled to avoid "
835 "man-in-the-middle attacks.");
836 options.num_local_forwards =
837 options.num_remote_forwards = 0;
839 if (options.tun_open != SSH_TUNMODE_NO) {
840 error("Tunnel forwarding is disabled to avoid "
841 "man-in-the-middle attacks.");
842 options.tun_open = SSH_TUNMODE_NO;
845 * XXX Should permit the user to change to use the new id.
846 * This could be done by converting the host key to an
847 * identifying sentence, tell that the host identifies itself
848 * by that sentence, and ask the user if he/she whishes to
849 * accept the authentication.
853 fatal("internal error");
857 if (options.check_host_ip && host_status != HOST_CHANGED &&
858 ip_status == HOST_CHANGED) {
859 snprintf(msg, sizeof(msg),
860 "Warning: the %s host key for '%.200s' "
861 "differs from the key for the IP address '%.128s'"
862 "\nOffending key for IP in %s:%d",
863 type, host, ip, ip_file, ip_line);
864 if (host_status == HOST_OK) {
866 snprintf(msg + len, sizeof(msg) - len,
867 "\nMatching host key in %s:%d",
868 host_file, host_line);
870 if (options.strict_host_key_checking == 1) {
872 error("Exiting, you have requested strict checking.");
874 } else if (options.strict_host_key_checking == 2) {
875 strlcat(msg, "\nAre you sure you want "
876 "to continue connecting (yes/no)? ", sizeof(msg));
894 /* returns 0 if key verifies or -1 if key does NOT verify */
896 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
901 if (options.verify_host_key_dns &&
902 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
904 if (flags & DNS_VERIFY_FOUND) {
906 if (options.verify_host_key_dns == 1 &&
907 flags & DNS_VERIFY_MATCH &&
908 flags & DNS_VERIFY_SECURE)
911 if (flags & DNS_VERIFY_MATCH) {
912 matching_host_key_dns = 1;
914 warn_changed_key(host_key);
915 error("Update the SSHFP RR in DNS with the new "
916 "host key to get rid of this message.");
921 /* return ok if the key can be found in an old keyfile */
922 if (stat(options.system_hostfile2, &st) == 0 ||
923 stat(options.user_hostfile2, &st) == 0) {
924 if (check_host_key(host, hostaddr, options.port, host_key,
925 RDONLY, options.user_hostfile2,
926 options.system_hostfile2) == 0)
929 return check_host_key(host, hostaddr, options.port, host_key,
930 RDRW, options.user_hostfile, options.system_hostfile);
934 * Starts a dialog with the server, and authenticates the current user on the
935 * server. This does not need any extra privileges. The basic connection
936 * to the server must already have been established before this is called.
937 * If login fails, this function prints an error and never returns.
938 * This function does not require super-user privileges.
941 ssh_login(Sensitive *sensitive, const char *orighost,
942 struct sockaddr *hostaddr, struct passwd *pw)
945 char *server_user, *local_user;
947 local_user = xstrdup(pw->pw_name);
948 server_user = options.user ? options.user : local_user;
950 /* Convert the user-supplied hostname into all lowercase. */
951 host = xstrdup(orighost);
952 for (cp = host; *cp; cp++)
954 *cp = (char)tolower(*cp);
956 /* Exchange protocol version identification strings with the server. */
957 ssh_exchange_identification();
959 /* Put the connection into non-blocking mode. */
960 packet_set_nonblocking();
963 /* authenticate user */
965 ssh_kex2(host, hostaddr);
966 ssh_userauth2(local_user, server_user, host, sensitive);
968 ssh_kex(host, hostaddr);
969 ssh_userauth1(local_user, server_user, host, sensitive);
975 ssh_put_password(char *password)
980 if (datafellows & SSH_BUG_PASSWORDPAD) {
981 packet_put_cstring(password);
984 size = roundup(strlen(password) + 1, 32);
985 padded = xcalloc(1, size);
986 strlcpy(padded, password, size);
987 packet_put_string(padded, size);
988 memset(padded, 0, size);
993 show_key_from_file(const char *file, const char *host, int keytype)
999 found = key_new(keytype);
1000 if ((ret = lookup_key_in_hostfile_by_type(file, host,
1001 keytype, found, &line))) {
1002 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
1003 logit("WARNING: %s key found for host %s\n"
1005 "%s key fingerprint %s.",
1006 key_type(found), host, file, line,
1007 key_type(found), fp);
1014 /* print all known host keys for a given host, but skip keys of given type */
1016 show_other_keys(const char *host, Key *key)
1018 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
1021 for (i = 0; type[i] != -1; i++) {
1022 if (type[i] == key->type)
1024 if (type[i] != KEY_RSA1 &&
1025 show_key_from_file(options.user_hostfile2, host, type[i])) {
1029 if (type[i] != KEY_RSA1 &&
1030 show_key_from_file(options.system_hostfile2, host, type[i])) {
1034 if (show_key_from_file(options.user_hostfile, host, type[i])) {
1038 if (show_key_from_file(options.system_hostfile, host, type[i])) {
1042 debug2("no key of type %d for host %s", type[i], host);
1048 warn_changed_key(Key *host_key)
1051 const char *type = key_type(host_key);
1053 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1055 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1056 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1057 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1058 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1059 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1060 error("It is also possible that the %s host key has just been changed.", type);
1061 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1063 error("Please contact your system administrator.");
1069 * Execute a local command
1072 ssh_local_cmd(const char *args)
1078 if (!options.permit_local_command ||
1079 args == NULL || !*args)
1082 if ((shell = getenv("SHELL")) == NULL)
1083 shell = _PATH_BSHELL;
1087 debug3("Executing %s -c \"%s\"", shell, args);
1088 execl(shell, shell, "-c", args, (char *)NULL);
1089 error("Couldn't execute %s -c \"%s\": %s",
1090 shell, args, strerror(errno));
1092 } else if (pid == -1)
1093 fatal("fork failed: %.100s", strerror(errno));
1094 while (waitpid(pid, &status, 0) == -1)
1096 fatal("Couldn't wait for child: %s", strerror(errno));
1098 if (!WIFEXITED(status))
1101 return (WEXITSTATUS(status));