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 1.110 2001/07/25 14:35:18 markus Exp $");
18 #include <openssl/bn.h>
28 #include "sshconnect.h"
35 char *client_version_string = NULL;
36 char *server_version_string = NULL;
38 extern Options options;
39 extern char *__progname;
41 /* AF_UNSPEC or AF_INET or AF_INET6 */
44 #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
45 #define INET6_ADDRSTRLEN 46
49 sockaddr_ntop(struct sockaddr *sa)
52 static char addrbuf[INET6_ADDRSTRLEN];
54 switch (sa->sa_family) {
56 addr = &((struct sockaddr_in *)sa)->sin_addr;
59 addr = &((struct sockaddr_in6 *)sa)->sin6_addr;
62 /* This case should be protected against elsewhere */
65 inet_ntop(sa->sa_family, addr, addrbuf, sizeof(addrbuf));
70 * Connect to the given ssh server using a proxy command.
73 ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
74 const char *proxy_command)
81 char strport[NI_MAXSERV];
83 /* Convert the port number into a string. */
84 snprintf(strport, sizeof strport, "%hu", port);
86 /* Build the final command string in the buffer by making the
87 appropriate substitutions to the given proxy command. */
88 buffer_init(&command);
89 for (cp = proxy_command; *cp; cp++) {
90 if (cp[0] == '%' && cp[1] == '%') {
91 buffer_append(&command, "%", 1);
95 if (cp[0] == '%' && cp[1] == 'h') {
96 buffer_append(&command, host, strlen(host));
100 if (cp[0] == '%' && cp[1] == 'p') {
101 buffer_append(&command, strport, strlen(strport));
105 buffer_append(&command, cp, 1);
107 buffer_append(&command, "\0", 1);
109 /* Get the final command string. */
110 command_string = buffer_ptr(&command);
112 /* Create pipes for communicating with the proxy. */
113 if (pipe(pin) < 0 || pipe(pout) < 0)
114 fatal("Could not create pipes to communicate with the proxy: %.100s",
117 debug("Executing proxy command: %.500s", command_string);
119 /* Fork and execute the proxy command. */
120 if ((pid = fork()) == 0) {
123 /* Child. Permanently give up superuser privileges. */
124 permanently_set_uid(pw);
126 /* Redirect stdin and stdout. */
129 if (dup2(pin[0], 0) < 0)
130 perror("dup2 stdin");
134 if (dup2(pout[1], 1) < 0)
135 perror("dup2 stdout");
136 /* Cannot be 1 because pin allocated two descriptors. */
139 /* Stderr is left as it is so that error messages get
140 printed on the user's terminal. */
141 argv[0] = _PATH_BSHELL;
143 argv[2] = command_string;
146 /* Execute the proxy command. Note that we gave up any
147 extra privileges above. */
148 execv(argv[0], argv);
154 fatal("fork failed: %.100s", strerror(errno));
156 /* Close child side of the descriptors. */
160 /* Free the command name. */
161 buffer_free(&command);
163 /* Set the connection file descriptors. */
164 packet_set_connection(pout[0], pin[1]);
166 /* Indicate OK return */
171 * Creates a (possibly privileged) socket for use as the ssh connection.
174 ssh_create_socket(struct passwd *pw, int privileged, int family)
177 struct addrinfo hints, *res;
180 * If we are running as root and want to connect to a privileged
181 * port, bind our own socket to a privileged port.
184 int p = IPPORT_RESERVED - 1;
185 sock = rresvport_af(&p, family);
187 error("rresvport: af=%d %.100s", family, strerror(errno));
189 debug("Allocated local port %d.", p);
193 * Just create an ordinary socket on arbitrary port. We use
194 * the user's uid to create the socket.
196 temporarily_use_uid(pw);
197 sock = socket(family, SOCK_STREAM, 0);
199 error("socket: %.100s", strerror(errno));
202 /* Bind the socket to an alternative local IP address */
203 if (options.bind_address == NULL)
206 memset(&hints, 0, sizeof(hints));
207 hints.ai_family = IPv4or6;
208 hints.ai_socktype = SOCK_STREAM;
209 hints.ai_flags = AI_PASSIVE;
210 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
212 error("getaddrinfo: %s: %s", options.bind_address,
213 gai_strerror(gaierr));
217 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
218 error("bind: %s: %s", options.bind_address, strerror(errno));
228 * Opens a TCP/IP connection to the remote server on the given host.
229 * The address of the remote host will be returned in hostaddr.
230 * If port is 0, the default port will be used. If anonymous is zero,
231 * a privileged port will be allocated to make the connection.
232 * This requires super-user privileges if anonymous is false.
233 * Connection_attempts specifies the maximum number of tries (one per
234 * second). If proxy_command is non-NULL, it specifies the command (with %h
235 * and %p substituted for host and port, respectively) to use to contact
239 * ECONNREFUSED if we got a "Connection Refused" by the peer on any address
240 * ECONNABORTED if we failed without a "Connection refused"
241 * Suitable error messages for the connection failure will already have been
245 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
246 u_short port, int connection_attempts,
247 int anonymous, struct passwd *pw,
248 const char *proxy_command)
252 int sock = -1, attempt;
253 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
254 struct addrinfo hints, *ai, *aitop;
255 struct linger linger;
258 * Did we get only other errors than "Connection refused" (which
259 * should block fallback to rsh and similar), or did we get at least
260 * one "Connection refused"?
262 int full_failure = 1;
264 debug("ssh_connect: getuid %u geteuid %u anon %d",
265 (u_int) getuid(), (u_int) geteuid(), anonymous);
267 /* Get default port if port has not been set. */
269 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
271 port = ntohs(sp->s_port);
273 port = SSH_DEFAULT_PORT;
275 /* If a proxy command is given, connect using it. */
276 if (proxy_command != NULL)
277 return ssh_proxy_connect(host, port, pw, proxy_command);
279 /* No proxy command. */
281 memset(&hints, 0, sizeof(hints));
282 hints.ai_family = IPv4or6;
283 hints.ai_socktype = SOCK_STREAM;
284 snprintf(strport, sizeof strport, "%d", port);
285 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
286 fatal("%s: %.100s: %s", __progname, host,
287 gai_strerror(gaierr));
290 * Try to connect several times. On some machines, the first time
291 * will sometimes fail. In general socket code appears to behave
292 * quite magically on many machines.
294 for (attempt = 0; ;) {
296 debug("Trying again...");
298 /* Loop through addresses for this host, and try each one in
299 sequence until the connection succeeds. */
300 for (ai = aitop; ai; ai = ai->ai_next) {
301 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
303 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
304 ntop, sizeof(ntop), strport, sizeof(strport),
305 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
306 error("ssh_connect: getnameinfo failed");
309 debug("Connecting to %.200s [%.100s] port %s.",
310 host, ntop, strport);
312 /* Create a socket for connecting. */
313 sock = ssh_create_socket(pw,
317 !anonymous && geteuid() == 0,
321 /* Any error is already output */
324 /* Connect to the host. We use the user's uid in the
325 * hope that it will help with tcp_wrappers showing
326 * the remote uid as root.
328 temporarily_use_uid(pw);
329 if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
330 /* Successful connection. */
331 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
335 if (errno == ECONNREFUSED)
337 log("ssh: connect to address %s port %s: %s",
338 sockaddr_ntop(ai->ai_addr), strport,
342 * Close the failed socket; there appear to
343 * be some problems when reusing a socket for
344 * which connect() has already returned an
347 shutdown(sock, SHUT_RDWR);
352 break; /* Successful connection. */
355 if (attempt >= connection_attempts)
357 /* Sleep a moment before retrying. */
363 /* Return failure if we didn't get a successful connection. */
364 if (attempt >= connection_attempts)
365 return full_failure ? ECONNABORTED : ECONNREFUSED;
367 debug("Connection established.");
370 * Set socket options. We would like the socket to disappear as soon
371 * as it has been closed for whatever reason.
373 /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
376 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
378 /* Set keepalives if requested. */
379 if (options.keepalives &&
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, i, mismatch;
399 int connection_in = packet_get_connection_in();
400 int connection_out = packet_get_connection_out();
401 int minor1 = PROTOCOL_MINOR_1;
403 /* Read other side\'s version identification. */
405 for (i = 0; i < sizeof(buf) - 1; i++) {
406 int len = atomicio(read, connection_in, &buf[i], 1);
408 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
410 fatal("ssh_exchange_identification: Connection closed by remote host");
411 if (buf[i] == '\r') {
414 continue; /**XXX wait for \n */
416 if (buf[i] == '\n') {
421 buf[sizeof(buf) - 1] = 0;
422 if (strncmp(buf, "SSH-", 4) == 0)
424 debug("ssh_exchange_identification: %s", buf);
426 server_version_string = xstrdup(buf);
429 * Check that the versions match. In future this might accept
430 * several versions and set appropriate flags to handle them.
432 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
433 &remote_major, &remote_minor, remote_version) != 3)
434 fatal("Bad remote protocol version identification: '%.100s'", buf);
435 debug("Remote protocol version %d.%d, remote software version %.100s",
436 remote_major, remote_minor, remote_version);
438 compat_datafellows(remote_version);
441 switch(remote_major) {
443 if (remote_minor == 99 &&
444 (options.protocol & SSH_PROTO_2) &&
445 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
449 if (!(options.protocol & SSH_PROTO_1)) {
453 if (remote_minor < 3) {
454 fatal("Remote machine has too old SSH software version.");
455 } else if (remote_minor == 3 || remote_minor == 4) {
456 /* We speak 1.3, too. */
459 if (options.forward_agent) {
460 log("Agent forwarding disabled for protocol 1.3");
461 options.forward_agent = 0;
466 if (options.protocol & SSH_PROTO_2) {
476 fatal("Protocol major versions differ: %d vs. %d",
477 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
479 /* Send our own protocol version identification. */
480 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
481 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
482 compat20 ? PROTOCOL_MINOR_2 : minor1,
484 if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
485 fatal("write: %.100s", strerror(errno));
486 client_version_string = xstrdup(buf);
487 chop(client_version_string);
488 chop(server_version_string);
489 debug("Local version string %.100s", client_version_string);
492 /* defaults to 'no' */
494 read_yes_or_no(const char *prompt, int defval)
500 if (options.batch_mode)
503 if (isatty(STDIN_FILENO))
506 f = fopen(_PATH_TTY, "rw");
514 fprintf(stderr, "%s", prompt);
515 if (fgets(buf, sizeof(buf), f) == NULL) {
517 * Print a newline (the prompt probably didn\'t have
520 fprintf(stderr, "\n");
521 strlcpy(buf, "no", sizeof buf);
523 /* Remove newline from response. */
524 if (strchr(buf, '\n'))
525 *strchr(buf, '\n') = 0;
529 if (strcmp(buf, "yes") == 0)
531 else if (strcmp(buf, "no") == 0)
534 fprintf(stderr, "Please type 'yes' or 'no'.\n");
545 * check whether the supplied host key is valid, return -1 if the key
546 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
550 check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
551 int readonly, const char *user_hostfile, const char *system_hostfile)
554 char *type = key_type(host_key);
556 char hostline[1000], *hostp, *fp;
557 HostStatus host_status;
558 HostStatus ip_status;
559 int local = 0, host_ip_differ = 0;
561 char ntop[NI_MAXHOST];
562 int host_line, ip_line;
563 const char *host_file = NULL, *ip_file = NULL;
566 * Force accepting of the host key for loopback/localhost. The
567 * problem is that if the home directory is NFS-mounted to multiple
568 * machines, localhost will refer to a different machine in each of
569 * them, and the user will get bogus HOST_CHANGED warnings. This
570 * essentially disables host authentication for localhost; however,
571 * this is probably not a real problem.
573 /** hostaddr == 0! */
574 switch (hostaddr->sa_family) {
576 local = (ntohl(((struct sockaddr_in *)hostaddr)->
577 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
578 salen = sizeof(struct sockaddr_in);
581 local = IN6_IS_ADDR_LOOPBACK(
582 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
583 salen = sizeof(struct sockaddr_in6);
587 salen = sizeof(struct sockaddr_storage);
590 if (local && options.host_key_alias == NULL) {
591 debug("Forcing accepting of host key for "
592 "loopback/localhost.");
597 * We don't have the remote ip-address for connections
598 * using a proxy command
600 if (options.proxy_command == NULL) {
601 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
602 NULL, 0, NI_NUMERICHOST) != 0)
603 fatal("check_host_key: getnameinfo failed");
606 ip = xstrdup("<no hostip for proxy command>");
609 * Turn off check_host_ip if the connection is to localhost, via proxy
610 * command or if we don't have a hostname to compare with
612 if (options.check_host_ip &&
613 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
614 options.check_host_ip = 0;
617 * Allow the user to record the key under a different name. This is
618 * useful for ssh tunneling over forwarded connections or if you run
619 * multiple sshd's on different ports on the same machine.
621 if (options.host_key_alias != NULL) {
622 host = options.host_key_alias;
623 debug("using hostkeyalias: %s", host);
627 * Store the host key from the known host file in here so that we can
628 * compare it with the key for the IP address.
630 file_key = key_new(host_key->type);
633 * Check if the host key is present in the user\'s list of known
634 * hosts or in the systemwide list.
636 host_file = user_hostfile;
637 host_status = check_host_in_hostfile(host_file, host, host_key,
638 file_key, &host_line);
639 if (host_status == HOST_NEW) {
640 host_file = system_hostfile;
641 host_status = check_host_in_hostfile(host_file, host, host_key,
642 file_key, &host_line);
645 * Also perform check for the ip address, skip the check if we are
646 * localhost or the hostname was an ip address to begin with
648 if (options.check_host_ip) {
649 Key *ip_key = key_new(host_key->type);
651 ip_file = user_hostfile;
652 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
654 if (ip_status == HOST_NEW) {
655 ip_file = system_hostfile;
656 ip_status = check_host_in_hostfile(ip_file, ip,
657 host_key, ip_key, &ip_line);
659 if (host_status == HOST_CHANGED &&
660 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
665 ip_status = host_status;
669 switch (host_status) {
671 /* The host is known and the key matches. */
672 debug("Host '%.200s' is known and matches the %s host key.",
674 debug("Found key in %s:%d", host_file, host_line);
675 if (options.check_host_ip && ip_status == HOST_NEW) {
677 log("%s host key for IP address "
678 "'%.128s' not in list of known hosts.",
680 else if (!add_host_to_hostfile(user_hostfile, ip,
682 log("Failed to add the %s host key for IP "
683 "address '%.128s' to the list of known "
684 "hosts (%.30s).", type, ip, user_hostfile);
686 log("Warning: Permanently added the %s host "
687 "key for IP address '%.128s' to the list "
688 "of known hosts.", type, ip);
694 /* The host is new. */
695 if (options.strict_host_key_checking == 1) {
697 * User has requested strict host key checking. We
698 * will not add the host key automatically. The only
699 * alternative left is to abort.
701 error("No %s host key is known for %.200s and you "
702 "have requested strict checking.", type, host);
704 } else if (options.strict_host_key_checking == 2) {
707 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
708 snprintf(prompt, sizeof(prompt),
709 "The authenticity of host '%.200s (%s)' can't be "
711 "%s key fingerprint is %s.\n"
712 "Are you sure you want to continue connecting "
713 "(yes/no)? ", host, ip, type, fp);
715 if (!read_yes_or_no(prompt, -1)) {
716 log("Aborted by user!");
720 if (options.check_host_ip && ip_status == HOST_NEW) {
721 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
727 * If not in strict mode, add the key automatically to the
728 * local known_hosts file.
730 if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
731 log("Failed to add the host to the list of known "
732 "hosts (%.500s).", user_hostfile);
734 log("Warning: Permanently added '%.200s' (%s) to the "
735 "list of known hosts.", hostp, type);
738 if (options.check_host_ip && host_ip_differ) {
740 if (ip_status == HOST_NEW)
742 else if (ip_status == HOST_OK)
743 msg = "is unchanged";
745 msg = "has a different value";
746 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
747 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
748 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
749 error("The %s host key for %s has changed,", type, host);
750 error("and the key for the according IP address %s", ip);
751 error("%s. This could either mean that", msg);
752 error("DNS SPOOFING is happening or the IP address for the host");
753 error("and its host key have changed at the same time.");
754 if (ip_status != HOST_NEW)
755 error("Offending key for IP in %s:%d", ip_file, ip_line);
757 /* The host key has changed. */
758 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
759 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
760 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
761 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
762 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
763 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
764 error("It is also possible that the %s host key has just been changed.", type);
765 error("The fingerprint for the %s key sent by the remote host is\n%s.",
767 error("Please contact your system administrator.");
768 error("Add correct host key in %.100s to get rid of this message.",
770 error("Offending key in %s:%d", host_file, host_line);
774 * If strict host key checking is in use, the user will have
775 * to edit the key manually and we can only abort.
777 if (options.strict_host_key_checking) {
778 error("%s host key for %.200s has changed and you have "
779 "requested strict checking.", type, host);
784 * If strict host key checking has not been requested, allow
785 * the connection but without password authentication or
788 if (options.password_authentication) {
789 error("Password authentication is disabled to avoid "
790 "man-in-the-middle attacks.");
791 options.password_authentication = 0;
793 if (options.forward_agent) {
794 error("Agent forwarding is disabled to avoid "
795 "man-in-the-middle attacks.");
796 options.forward_agent = 0;
798 if (options.forward_x11) {
799 error("X11 forwarding is disabled to avoid "
800 "man-in-the-middle attacks.");
801 options.forward_x11 = 0;
803 if (options.num_local_forwards > 0 ||
804 options.num_remote_forwards > 0) {
805 error("Port forwarding is disabled to avoid "
806 "man-in-the-middle attacks.");
807 options.num_local_forwards =
808 options.num_remote_forwards = 0;
811 * XXX Should permit the user to change to use the new id.
812 * This could be done by converting the host key to an
813 * identifying sentence, tell that the host identifies itself
814 * by that sentence, and ask the user if he/she whishes to
815 * accept the authentication.
820 if (options.check_host_ip && host_status != HOST_CHANGED &&
821 ip_status == HOST_CHANGED) {
822 log("Warning: the %s host key for '%.200s' "
823 "differs from the key for the IP address '%.128s'",
825 if (host_status == HOST_OK)
826 log("Matching host key in %s:%d", host_file, host_line);
827 log("Offending key for IP in %s:%d", ip_file, ip_line);
828 if (options.strict_host_key_checking == 1) {
829 error("Exiting, you have requested strict checking.");
831 } else if (options.strict_host_key_checking == 2) {
832 if (!read_yes_or_no("Are you sure you want "
833 "to continue connecting (yes/no)? ", -1)) {
834 log("Aborted by user!");
849 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
853 /* return ok if the key can be found in an old keyfile */
854 if (stat(options.system_hostfile2, &st) == 0 ||
855 stat(options.user_hostfile2, &st) == 0) {
856 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
857 options.user_hostfile2, options.system_hostfile2) == 0)
860 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
861 options.user_hostfile, options.system_hostfile);
865 * Starts a dialog with the server, and authenticates the current user on the
866 * server. This does not need any extra privileges. The basic connection
867 * to the server must already have been established before this is called.
868 * If login fails, this function prints an error and never returns.
869 * This function does not require super-user privileges.
872 ssh_login(Key **keys, int nkeys, const char *orighost,
873 struct sockaddr *hostaddr, struct passwd *pw)
876 char *server_user, *local_user;
878 local_user = xstrdup(pw->pw_name);
879 server_user = options.user ? options.user : local_user;
881 /* Convert the user-supplied hostname into all lowercase. */
882 host = xstrdup(orighost);
883 for (cp = host; *cp; cp++)
887 /* Exchange protocol version identification strings with the server. */
888 ssh_exchange_identification();
890 /* Put the connection into non-blocking mode. */
891 packet_set_nonblocking();
894 /* authenticate user */
896 ssh_kex2(host, hostaddr);
897 ssh_userauth2(local_user, server_user, host, keys, nkeys);
899 ssh_kex(host, hostaddr);
900 ssh_userauth1(local_user, server_user, host, keys, nkeys);
905 ssh_put_password(char *password)
910 if (datafellows & SSH_BUG_PASSWORDPAD) {
911 packet_put_cstring(password);
914 size = roundup(strlen(password) + 1, 32);
915 padded = xmalloc(size);
916 memset(padded, 0, size);
917 strlcpy(padded, password, size);
918 packet_put_string(padded, size);
919 memset(padded, 0, size);