1 /* $OpenBSD: sshconnect.c,v 1.365 2023/11/20 02:50:00 djm 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>
27 #include <netinet/in.h>
28 #include <arpa/inet.h>
58 #include "sshconnect.h"
64 #include "monitor_fdpass.h"
72 struct sshkey *previous_host_key = NULL;
74 static int matching_host_key_dns = 0;
76 static pid_t proxy_command_pid = 0;
79 extern int debug_flag;
80 extern Options options;
81 extern char *__progname;
83 static int show_other_keys(struct hostkeys *, struct sshkey *);
84 static void warn_changed_key(struct sshkey *);
86 /* Expand a proxy command */
88 expand_proxy_command(const char *proxy_command, const char *user,
89 const char *host, const char *host_arg, int port)
91 char *tmp, *ret, strport[NI_MAXSERV];
92 const char *keyalias = options.host_key_alias ?
93 options.host_key_alias : host_arg;
95 snprintf(strport, sizeof strport, "%d", port);
96 xasprintf(&tmp, "exec %s", proxy_command);
97 ret = percent_expand(tmp,
109 * Connect to the given ssh server using a proxy command that passes a
110 * a connected fd back to us.
113 ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host,
114 const char *host_arg, u_short port, const char *proxy_command)
116 char *command_string;
121 if ((shell = getenv("SHELL")) == NULL)
122 shell = _PATH_BSHELL;
124 if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) == -1)
125 fatal("Could not create socketpair to communicate with "
126 "proxy dialer: %.100s", strerror(errno));
128 command_string = expand_proxy_command(proxy_command, options.user,
129 host, host_arg, port);
130 debug("Executing proxy dialer command: %.500s", command_string);
132 /* Fork and execute the proxy command. */
133 if ((pid = fork()) == 0) {
137 /* Redirect stdin and stdout. */
139 if (dup2(sp[0], 0) == -1)
140 perror("dup2 stdin");
143 if (dup2(sp[0], 1) == -1)
144 perror("dup2 stdout");
150 * Stderr is left for non-ControlPersist connections is so
151 * error messages may be printed on the user's terminal.
153 if (!debug_flag && options.control_path != NULL &&
154 options.control_persist && stdfd_devnull(0, 0, 1) == -1)
155 error_f("stdfd_devnull failed");
159 argv[2] = command_string;
163 * Execute the proxy command.
164 * Note that we gave up any extra privileges above.
166 execv(argv[0], argv);
172 fatal("fork failed: %.100s", strerror(errno));
174 free(command_string);
176 if ((sock = mm_receive_fd(sp[1])) == -1)
177 fatal("proxy dialer did not pass back a connection");
180 while (waitpid(pid, NULL, 0) == -1)
182 fatal("Couldn't wait for child: %s", strerror(errno));
184 /* Set the connection file descriptors. */
185 if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
186 return -1; /* ssh_packet_set_connection logs error */
192 * Connect to the given ssh server using a proxy command.
195 ssh_proxy_connect(struct ssh *ssh, const char *host, const char *host_arg,
196 u_short port, const char *proxy_command)
198 char *command_string;
203 if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
204 shell = _PATH_BSHELL;
206 /* Create pipes for communicating with the proxy. */
207 if (pipe(pin) == -1 || pipe(pout) == -1)
208 fatal("Could not create pipes to communicate with the proxy: %.100s",
211 command_string = expand_proxy_command(proxy_command, options.user,
212 host, host_arg, port);
213 debug("Executing proxy command: %.500s", command_string);
215 /* Fork and execute the proxy command. */
216 if ((pid = fork()) == 0) {
219 /* Redirect stdin and stdout. */
222 if (dup2(pin[0], 0) == -1)
223 perror("dup2 stdin");
227 if (dup2(pout[1], 1) == -1)
228 perror("dup2 stdout");
229 /* Cannot be 1 because pin allocated two descriptors. */
233 * Stderr is left for non-ControlPersist connections is so
234 * error messages may be printed on the user's terminal.
236 if (!debug_flag && options.control_path != NULL &&
237 options.control_persist && stdfd_devnull(0, 0, 1) == -1)
238 error_f("stdfd_devnull failed");
242 argv[2] = command_string;
246 * Execute the proxy command. Note that we gave up any
247 * extra privileges above.
249 ssh_signal(SIGPIPE, SIG_DFL);
250 execv(argv[0], argv);
256 fatal("fork failed: %.100s", strerror(errno));
258 proxy_command_pid = pid; /* save pid to clean up later */
260 /* Close child side of the descriptors. */
264 /* Free the command name. */
265 free(command_string);
267 /* Set the connection file descriptors. */
268 if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL)
269 return -1; /* ssh_packet_set_connection logs error */
275 ssh_kill_proxy_command(void)
278 * Send SIGHUP to proxy command if used. We don't wait() in
279 * case it hangs and instead rely on init to reap the child
281 if (proxy_command_pid > 1)
282 kill(proxy_command_pid, SIGHUP);
285 #ifdef HAVE_IFADDRS_H
287 * Search a interface address list (returned from getifaddrs(3)) for an
288 * address that matches the desired address family on the specified interface.
289 * Returns 0 and fills in *resultp and *rlenp on success. Returns -1 on failure.
292 check_ifaddrs(const char *ifname, int af, const struct ifaddrs *ifaddrs,
293 struct sockaddr_storage *resultp, socklen_t *rlenp)
295 struct sockaddr_in6 *sa6;
296 struct sockaddr_in *sa;
297 struct in6_addr *v6addr;
298 const struct ifaddrs *ifa;
302 * Prefer addresses that are not loopback or linklocal, but use them
303 * if nothing else matches.
305 for (allow_local = 0; allow_local < 2; allow_local++) {
306 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
307 if (ifa->ifa_addr == NULL || ifa->ifa_name == NULL ||
308 (ifa->ifa_flags & IFF_UP) == 0 ||
309 ifa->ifa_addr->sa_family != af ||
310 strcmp(ifa->ifa_name, options.bind_interface) != 0)
312 switch (ifa->ifa_addr->sa_family) {
314 sa = (struct sockaddr_in *)ifa->ifa_addr;
315 if (!allow_local && sa->sin_addr.s_addr ==
316 htonl(INADDR_LOOPBACK))
318 if (*rlenp < sizeof(struct sockaddr_in)) {
319 error_f("v4 addr doesn't fit");
322 *rlenp = sizeof(struct sockaddr_in);
323 memcpy(resultp, sa, *rlenp);
326 sa6 = (struct sockaddr_in6 *)ifa->ifa_addr;
327 v6addr = &sa6->sin6_addr;
329 (IN6_IS_ADDR_LINKLOCAL(v6addr) ||
330 IN6_IS_ADDR_LOOPBACK(v6addr)))
332 if (*rlenp < sizeof(struct sockaddr_in6)) {
333 error_f("v6 addr doesn't fit");
336 *rlenp = sizeof(struct sockaddr_in6);
337 memcpy(resultp, sa6, *rlenp);
347 * Creates a socket for use as the ssh connection.
350 ssh_create_socket(struct addrinfo *ai)
353 struct sockaddr_storage bindaddr;
354 socklen_t bindaddrlen = 0;
355 struct addrinfo hints, *res = NULL;
356 #ifdef HAVE_IFADDRS_H
357 struct ifaddrs *ifaddrs = NULL;
359 char ntop[NI_MAXHOST];
361 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
363 error("socket: %s", strerror(errno));
366 (void)fcntl(sock, F_SETFD, FD_CLOEXEC);
368 /* Use interactive QOS (if specified) until authentication completed */
369 if (options.ip_qos_interactive != INT_MAX)
370 set_sock_tos(sock, options.ip_qos_interactive);
372 /* Bind the socket to an alternative local IP address */
373 if (options.bind_address == NULL && options.bind_interface == NULL)
376 if (options.bind_address != NULL) {
377 memset(&hints, 0, sizeof(hints));
378 hints.ai_family = ai->ai_family;
379 hints.ai_socktype = ai->ai_socktype;
380 hints.ai_protocol = ai->ai_protocol;
381 hints.ai_flags = AI_PASSIVE;
382 if ((r = getaddrinfo(options.bind_address, NULL,
383 &hints, &res)) != 0) {
384 error("getaddrinfo: %s: %s", options.bind_address,
385 ssh_gai_strerror(r));
389 error("getaddrinfo: no addrs");
392 memcpy(&bindaddr, res->ai_addr, res->ai_addrlen);
393 bindaddrlen = res->ai_addrlen;
394 } else if (options.bind_interface != NULL) {
395 #ifdef HAVE_IFADDRS_H
396 if ((r = getifaddrs(&ifaddrs)) != 0) {
397 error("getifaddrs: %s: %s", options.bind_interface,
401 bindaddrlen = sizeof(bindaddr);
402 if (check_ifaddrs(options.bind_interface, ai->ai_family,
403 ifaddrs, &bindaddr, &bindaddrlen) != 0) {
404 logit("getifaddrs: %s: no suitable addresses",
405 options.bind_interface);
409 error("BindInterface not supported on this platform.");
412 if ((r = getnameinfo((struct sockaddr *)&bindaddr, bindaddrlen,
413 ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST)) != 0) {
414 error_f("getnameinfo failed: %s", ssh_gai_strerror(r));
417 if (bind(sock, (struct sockaddr *)&bindaddr, bindaddrlen) != 0) {
418 error("bind %s: %s", ntop, strerror(errno));
421 debug_f("bound to %s", ntop);
430 #ifdef HAVE_IFADDRS_H
432 freeifaddrs(ifaddrs);
438 * Opens a TCP/IP connection to the remote server on the given host.
439 * The address of the remote host will be returned in hostaddr.
440 * If port is 0, the default port will be used.
441 * Connection_attempts specifies the maximum number of tries (one per
442 * second). If proxy_command is non-NULL, it specifies the command (with %h
443 * and %p substituted for host and port, respectively) to use to contact
447 ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop,
448 struct sockaddr_storage *hostaddr, u_short port, int connection_attempts,
449 int *timeout_ms, int want_keepalive)
451 int on = 1, saved_timeout_ms = *timeout_ms;
452 int oerrno, sock = -1, attempt;
453 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
456 debug3_f("entering");
457 memset(ntop, 0, sizeof(ntop));
458 memset(strport, 0, sizeof(strport));
460 for (attempt = 0; attempt < connection_attempts; attempt++) {
462 /* Sleep a moment before retrying. */
464 debug("Trying again...");
467 * Loop through addresses for this host, and try each one in
468 * sequence until the connection succeeds.
470 for (ai = aitop; ai; ai = ai->ai_next) {
471 if (ai->ai_family != AF_INET &&
472 ai->ai_family != AF_INET6) {
473 errno = EAFNOSUPPORT;
476 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
477 ntop, sizeof(ntop), strport, sizeof(strport),
478 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
480 error_f("getnameinfo failed");
484 if (options.address_family != AF_UNSPEC &&
485 ai->ai_family != options.address_family) {
486 debug2_f("skipping address [%s]:%s: "
487 "wrong address family", ntop, strport);
488 errno = EAFNOSUPPORT;
492 debug("Connecting to %.200s [%.100s] port %s.",
493 host, ntop, strport);
495 /* Create a socket for connecting. */
496 sock = ssh_create_socket(ai);
498 /* Any error is already output */
503 *timeout_ms = saved_timeout_ms;
504 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
506 /* Successful connection. */
507 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
511 debug("connect to address %s port %s: %s",
512 ntop, strport, strerror(errno));
519 break; /* Successful connection. */
522 /* Return failure if we didn't get a successful connection. */
524 error("ssh: connect to host %s port %s: %s",
525 host, strport, errno == 0 ? "failure" : strerror(errno));
529 debug("Connection established.");
531 /* Set SO_KEEPALIVE if requested. */
532 if (want_keepalive &&
533 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
535 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
537 /* Set the connection. */
538 if (ssh_packet_set_connection(ssh, sock, sock) == NULL)
539 return -1; /* ssh_packet_set_connection logs error */
545 ssh_connect(struct ssh *ssh, const char *host, const char *host_arg,
546 struct addrinfo *addrs, struct sockaddr_storage *hostaddr, u_short port,
547 int connection_attempts, int *timeout_ms, int want_keepalive)
551 if (options.proxy_command == NULL) {
552 return ssh_connect_direct(ssh, host, addrs, hostaddr, port,
553 connection_attempts, timeout_ms, want_keepalive);
554 } else if (strcmp(options.proxy_command, "-") == 0) {
555 if ((in = dup(STDIN_FILENO)) == -1 ||
556 (out = dup(STDOUT_FILENO)) == -1) {
559 error_f("dup() in/out failed");
560 return -1; /* ssh_packet_set_connection logs error */
562 if ((ssh_packet_set_connection(ssh, in, out)) == NULL)
563 return -1; /* ssh_packet_set_connection logs error */
565 } else if (options.proxy_use_fdpass) {
566 return ssh_proxy_fdpass_connect(ssh, host, host_arg, port,
567 options.proxy_command);
569 return ssh_proxy_connect(ssh, host, host_arg, port,
570 options.proxy_command);
573 /* defaults to 'no' */
575 confirm(const char *prompt, const char *fingerprint)
577 const char *msg, *again = "Please type 'yes' or 'no': ";
578 const char *again_fp = "Please type 'yes', 'no' or the fingerprint: ";
582 if (options.batch_mode)
584 for (msg = prompt;;msg = fingerprint ? again_fp : again) {
585 cp = p = read_passphrase(msg, RP_ECHO);
588 p += strspn(p, " \t"); /* skip leading whitespace */
589 p[strcspn(p, " \t\n")] = '\0'; /* remove trailing whitespace */
590 if (p[0] == '\0' || strcasecmp(p, "no") == 0)
592 else if (strcasecmp(p, "yes") == 0 || (fingerprint != NULL &&
593 strcmp(p, fingerprint) == 0))
602 sockaddr_is_local(struct sockaddr *hostaddr)
604 switch (hostaddr->sa_family) {
606 return (ntohl(((struct sockaddr_in *)hostaddr)->
607 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
609 return IN6_IS_ADDR_LOOPBACK(
610 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
617 * Prepare the hostname and ip address strings that are used to lookup
618 * host keys in known_hosts files. These may have a port number appended.
621 get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
622 u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
624 char ntop[NI_MAXHOST];
627 switch (hostaddr == NULL ? -1 : hostaddr->sa_family) {
632 addrlen = sizeof(struct sockaddr_in);
635 addrlen = sizeof(struct sockaddr_in6);
638 addrlen = sizeof(struct sockaddr);
643 * We don't have the remote ip-address for connections
644 * using a proxy command
646 if (hostfile_ipaddr != NULL) {
647 if (options.proxy_command == NULL) {
648 if (getnameinfo(hostaddr, addrlen,
649 ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
650 fatal_f("getnameinfo failed");
651 *hostfile_ipaddr = put_host_port(ntop, port);
653 *hostfile_ipaddr = xstrdup("<no hostip for proxy "
659 * Allow the user to record the key under a different name or
660 * differentiate a non-standard port. This is useful for ssh
661 * tunneling over forwarded connections or if you run multiple
662 * sshd's on different ports on the same machine.
664 if (hostfile_hostname != NULL) {
665 if (options.host_key_alias != NULL) {
666 *hostfile_hostname = xstrdup(options.host_key_alias);
667 debug("using hostkeyalias: %s", *hostfile_hostname);
669 *hostfile_hostname = put_host_port(hostname, port);
674 /* returns non-zero if path appears in hostfiles, or 0 if not. */
676 path_in_hostfiles(const char *path, char **hostfiles, u_int num_hostfiles)
680 for (i = 0; i < num_hostfiles; i++) {
681 if (strcmp(path, hostfiles[i]) == 0)
687 struct find_by_key_ctx {
688 const char *host, *ip;
689 const struct sshkey *key;
694 /* Try to replace home directory prefix (per $HOME) with a ~/ sequence */
696 try_tilde_unexpand(const char *path)
698 char *home, *ret = NULL;
702 return xstrdup(path);
703 if ((home = getenv("HOME")) == NULL || (l = strlen(home)) == 0)
704 return xstrdup(path);
705 if (strncmp(path, home, l) != 0)
706 return xstrdup(path);
708 * ensure we have matched on a path boundary: either the $HOME that
709 * we just compared ends with a '/' or the next character of the path
712 if (home[l - 1] != '/' && path[l] != '/')
713 return xstrdup(path);
716 xasprintf(&ret, "~/%s", path + l);
721 hostkeys_find_by_key_cb(struct hostkey_foreach_line *l, void *_ctx)
723 struct find_by_key_ctx *ctx = (struct find_by_key_ctx *)_ctx;
726 /* we are looking for keys with names that *do not* match */
727 if ((l->match & HKF_MATCH_HOST) != 0)
729 /* not interested in marker lines */
730 if (l->marker != MRK_NONE)
732 /* we are only interested in exact key matches */
733 if (l->key == NULL || !sshkey_equal(ctx->key, l->key))
735 path = try_tilde_unexpand(l->path);
736 debug_f("found matching key in %s:%lu", path, l->linenum);
737 ctx->names = xrecallocarray(ctx->names,
738 ctx->nnames, ctx->nnames + 1, sizeof(*ctx->names));
739 xasprintf(&ctx->names[ctx->nnames], "%s:%lu: %s", path, l->linenum,
740 strncmp(l->hosts, HASH_MAGIC, strlen(HASH_MAGIC)) == 0 ?
741 "[hashed name]" : l->hosts);
748 hostkeys_find_by_key_hostfile(const char *file, const char *which,
749 struct find_by_key_ctx *ctx)
753 debug3_f("trying %s hostfile \"%s\"", which, file);
754 if ((r = hostkeys_foreach(file, hostkeys_find_by_key_cb, ctx,
755 ctx->host, ctx->ip, HKF_WANT_PARSE_KEY, 0)) != 0) {
756 if (r == SSH_ERR_SYSTEM_ERROR && errno == ENOENT) {
757 debug_f("hostkeys file %s does not exist", file);
760 error_fr(r, "hostkeys_foreach failed for %s", file);
767 * Find 'key' in known hosts file(s) that do not match host/ip.
768 * Used to display also-known-as information for previously-unseen hostkeys.
771 hostkeys_find_by_key(const char *host, const char *ip, const struct sshkey *key,
772 char **user_hostfiles, u_int num_user_hostfiles,
773 char **system_hostfiles, u_int num_system_hostfiles,
774 char ***names, u_int *nnames)
776 struct find_by_key_ctx ctx = {0, 0, 0, 0, 0};
782 if (key == NULL || sshkey_is_cert(key))
789 for (i = 0; i < num_user_hostfiles; i++) {
790 if (hostkeys_find_by_key_hostfile(user_hostfiles[i],
794 for (i = 0; i < num_system_hostfiles; i++) {
795 if (hostkeys_find_by_key_hostfile(system_hostfiles[i],
796 "system", &ctx) != 0)
801 *nnames = ctx.nnames;
806 for (i = 0; i < ctx.nnames; i++)
811 #define MAX_OTHER_NAMES 8 /* Maximum number of names to list */
813 other_hostkeys_message(const char *host, const char *ip,
814 const struct sshkey *key,
815 char **user_hostfiles, u_int num_user_hostfiles,
816 char **system_hostfiles, u_int num_system_hostfiles)
818 char *ret = NULL, **othernames = NULL;
819 u_int i, n, num_othernames = 0;
821 hostkeys_find_by_key(host, ip, key,
822 user_hostfiles, num_user_hostfiles,
823 system_hostfiles, num_system_hostfiles,
824 &othernames, &num_othernames);
825 if (num_othernames == 0)
826 return xstrdup("This key is not known by any other names.");
828 xasprintf(&ret, "This host key is known by the following other "
832 if (n > MAX_OTHER_NAMES)
834 for (i = 0; i < n; i++) {
835 xextendf(&ret, "\n", " %s", othernames[i]);
837 if (n < num_othernames) {
838 xextendf(&ret, "\n", " (%d additional names omitted)",
841 for (i = 0; i < num_othernames; i++)
848 load_hostkeys_command(struct hostkeys *hostkeys, const char *command_template,
849 const char *invocation, const struct ssh_conn_info *cinfo,
850 const struct sshkey *host_key, const char *hostfile_hostname)
853 char *key_fp = NULL, *keytext = NULL, *tmp;
854 char *command = NULL, *tag = NULL, **av = NULL;
857 void (*osigchld)(int);
859 xasprintf(&tag, "KnownHostsCommand-%s", invocation);
861 if (host_key != NULL) {
862 if ((key_fp = sshkey_fingerprint(host_key,
863 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL)
864 fatal_f("sshkey_fingerprint failed");
865 if ((r = sshkey_to_base64(host_key, &keytext)) != 0)
866 fatal_fr(r, "sshkey_to_base64 failed");
869 * NB. all returns later this function should go via "out" to
870 * ensure the original SIGCHLD handler is restored properly.
872 osigchld = ssh_signal(SIGCHLD, SIG_DFL);
874 /* Turn the command into an argument vector */
875 if (argv_split(command_template, &ac, &av, 0) != 0) {
876 error("%s \"%s\" contains invalid quotes", tag,
881 error("%s \"%s\" yielded no arguments", tag,
885 for (i = 1; i < ac; i++) {
886 tmp = percent_dollar_expand(av[i],
887 DEFAULT_CLIENT_PERCENT_EXPAND_ARGS(cinfo),
888 "H", hostfile_hostname,
890 "t", host_key == NULL ? "NONE" : sshkey_ssh_name(host_key),
891 "f", key_fp == NULL ? "NONE" : key_fp,
892 "K", keytext == NULL ? "NONE" : keytext,
895 fatal_f("percent_expand failed");
899 /* Prepare a printable command for logs, etc. */
900 command = argv_assemble(ac, av);
902 if ((pid = subprocess(tag, command, ac, av, &f,
903 SSH_SUBPROCESS_STDOUT_CAPTURE|SSH_SUBPROCESS_UNSAFE_PATH|
904 SSH_SUBPROCESS_PRESERVE_ENV, NULL, NULL, NULL)) == 0)
907 load_hostkeys_file(hostkeys, hostfile_hostname, tag, f, 1);
909 if (exited_cleanly(pid, tag, command, 0) != 0)
910 fatal("KnownHostsCommand failed");
915 ssh_signal(SIGCHLD, osigchld);
916 for (i = 0; i < ac; i++)
926 * check whether the supplied host key is valid, return -1 if the key
927 * is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
933 check_host_key(char *hostname, const struct ssh_conn_info *cinfo,
934 struct sockaddr *hostaddr, u_short port,
935 struct sshkey *host_key, int readonly, int clobber_port,
936 char **user_hostfiles, u_int num_user_hostfiles,
937 char **system_hostfiles, u_int num_system_hostfiles,
938 const char *hostfile_command)
940 HostStatus host_status = -1, ip_status = -1;
941 struct sshkey *raw_key = NULL;
942 char *ip = NULL, *host = NULL;
943 char hostline[1000], *hostp, *fp, *ra;
945 const char *type, *fail_reason = NULL;
946 const struct hostkey_entry *host_found = NULL, *ip_found = NULL;
947 int len, cancelled_forwarding = 0, confirmed;
948 int local = sockaddr_is_local(hostaddr);
949 int r, want_cert = sshkey_is_cert(host_key), host_ip_differ = 0;
950 int hostkey_trusted = 0; /* Known or explicitly accepted by user */
951 struct hostkeys *host_hostkeys, *ip_hostkeys;
955 * Force accepting of the host key for loopback/localhost. The
956 * problem is that if the home directory is NFS-mounted to multiple
957 * machines, localhost will refer to a different machine in each of
958 * them, and the user will get bogus HOST_CHANGED warnings. This
959 * essentially disables host authentication for localhost; however,
960 * this is probably not a real problem.
962 if (options.no_host_authentication_for_localhost == 1 && local &&
963 options.host_key_alias == NULL) {
964 debug("Forcing accepting of host key for "
965 "loopback/localhost.");
966 options.update_hostkeys = 0;
971 * Don't ever try to write an invalid name to a known hosts file.
972 * Note: do this before get_hostfile_hostname_ipaddr() to catch
973 * '[' or ']' in the name before they are added.
975 if (strcspn(hostname, "@?*#[]|'\'\"\\") != strlen(hostname)) {
976 debug_f("invalid hostname \"%s\"; will not record: %s",
977 hostname, fail_reason);
982 * Prepare the hostname and address strings used for hostkey lookup.
983 * In some cases, these will have a port number appended.
985 get_hostfile_hostname_ipaddr(hostname, hostaddr,
986 clobber_port ? 0 : port, &host, &ip);
989 * Turn off check_host_ip if the connection is to localhost, via proxy
990 * command or if we don't have a hostname to compare with
992 if (options.check_host_ip && (local ||
993 strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
994 options.check_host_ip = 0;
996 host_hostkeys = init_hostkeys();
997 for (i = 0; i < num_user_hostfiles; i++)
998 load_hostkeys(host_hostkeys, host, user_hostfiles[i], 0);
999 for (i = 0; i < num_system_hostfiles; i++)
1000 load_hostkeys(host_hostkeys, host, system_hostfiles[i], 0);
1001 if (hostfile_command != NULL && !clobber_port) {
1002 load_hostkeys_command(host_hostkeys, hostfile_command,
1003 "HOSTNAME", cinfo, host_key, host);
1007 if (!want_cert && options.check_host_ip) {
1008 ip_hostkeys = init_hostkeys();
1009 for (i = 0; i < num_user_hostfiles; i++)
1010 load_hostkeys(ip_hostkeys, ip, user_hostfiles[i], 0);
1011 for (i = 0; i < num_system_hostfiles; i++)
1012 load_hostkeys(ip_hostkeys, ip, system_hostfiles[i], 0);
1013 if (hostfile_command != NULL && !clobber_port) {
1014 load_hostkeys_command(ip_hostkeys, hostfile_command,
1015 "ADDRESS", cinfo, host_key, ip);
1020 /* Reload these as they may have changed on cert->key downgrade */
1021 want_cert = sshkey_is_cert(host_key);
1022 type = sshkey_type(host_key);
1025 * Check if the host key is present in the user's list of known
1026 * hosts or in the systemwide list.
1028 host_status = check_key_in_hostkeys(host_hostkeys, host_key,
1032 * If there are no hostfiles, or if the hostkey was found via
1033 * KnownHostsCommand, then don't try to touch the disk.
1035 if (!readonly && (num_user_hostfiles == 0 ||
1036 (host_found != NULL && host_found->note != 0)))
1040 * Also perform check for the ip address, skip the check if we are
1041 * localhost, looking for a certificate, or the hostname was an ip
1042 * address to begin with.
1044 if (!want_cert && ip_hostkeys != NULL) {
1045 ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
1047 if (host_status == HOST_CHANGED &&
1048 (ip_status != HOST_CHANGED ||
1049 (ip_found != NULL &&
1050 !sshkey_equal(ip_found->key, host_found->key))))
1053 ip_status = host_status;
1055 switch (host_status) {
1057 /* The host is known and the key matches. */
1058 debug("Host '%.200s' is known and matches the %s host %s.",
1059 host, type, want_cert ? "certificate" : "key");
1060 debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
1061 host_found->file, host_found->line);
1063 if (sshkey_cert_check_host(host_key,
1064 options.host_key_alias == NULL ?
1065 hostname : options.host_key_alias, 0,
1066 options.ca_sign_algorithms, &fail_reason) != 0) {
1067 error("%s", fail_reason);
1071 * Do not attempt hostkey update if a certificate was
1072 * successfully matched.
1074 if (options.update_hostkeys != 0) {
1075 options.update_hostkeys = 0;
1076 debug3_f("certificate host key in use; "
1077 "disabling UpdateHostkeys");
1080 /* Turn off UpdateHostkeys if key was in system known_hosts */
1081 if (options.update_hostkeys != 0 &&
1082 (path_in_hostfiles(host_found->file,
1083 system_hostfiles, num_system_hostfiles) ||
1084 (ip_status == HOST_OK && ip_found != NULL &&
1085 path_in_hostfiles(ip_found->file,
1086 system_hostfiles, num_system_hostfiles)))) {
1087 options.update_hostkeys = 0;
1088 debug3_f("host key found in GlobalKnownHostsFile; "
1089 "disabling UpdateHostkeys");
1091 if (options.update_hostkeys != 0 && host_found->note) {
1092 options.update_hostkeys = 0;
1093 debug3_f("host key found via KnownHostsCommand; "
1094 "disabling UpdateHostkeys");
1096 if (options.check_host_ip && ip_status == HOST_NEW) {
1097 if (readonly || want_cert)
1098 logit("%s host key for IP address "
1099 "'%.128s' not in list of known hosts.",
1101 else if (!add_host_to_hostfile(user_hostfiles[0], ip,
1102 host_key, options.hash_known_hosts))
1103 logit("Failed to add the %s host key for IP "
1104 "address '%.128s' to the list of known "
1105 "hosts (%.500s).", type, ip,
1108 logit("Warning: Permanently added the %s host "
1109 "key for IP address '%.128s' to the list "
1110 "of known hosts.", type, ip);
1111 } else if (options.visual_host_key) {
1112 fp = sshkey_fingerprint(host_key,
1113 options.fingerprint_hash, SSH_FP_DEFAULT);
1114 ra = sshkey_fingerprint(host_key,
1115 options.fingerprint_hash, SSH_FP_RANDOMART);
1116 if (fp == NULL || ra == NULL)
1117 fatal_f("sshkey_fingerprint failed");
1118 logit("Host key fingerprint is %s\n%s", fp, ra);
1122 hostkey_trusted = 1;
1125 if (options.host_key_alias == NULL && port != 0 &&
1126 port != SSH_DEFAULT_PORT && !clobber_port) {
1127 debug("checking without port identifier");
1128 if (check_host_key(hostname, cinfo, hostaddr, 0,
1129 host_key, ROQUIET, 1,
1130 user_hostfiles, num_user_hostfiles,
1131 system_hostfiles, num_system_hostfiles,
1132 hostfile_command) == 0) {
1133 debug("found matching key w/out port");
1137 if (readonly || want_cert)
1139 /* The host is new. */
1140 if (options.strict_host_key_checking ==
1141 SSH_STRICT_HOSTKEY_YES) {
1143 * User has requested strict host key checking. We
1144 * will not add the host key automatically. The only
1145 * alternative left is to abort.
1147 error("No %s host key is known for %.200s and you "
1148 "have requested strict checking.", type, host);
1150 } else if (options.strict_host_key_checking ==
1151 SSH_STRICT_HOSTKEY_ASK) {
1152 char *msg1 = NULL, *msg2 = NULL;
1154 xasprintf(&msg1, "The authenticity of host "
1155 "'%.200s (%s)' can't be established", host, ip);
1157 if (show_other_keys(host_hostkeys, host_key)) {
1158 xextendf(&msg1, "\n", "but keys of different "
1159 "type are already known for this host.");
1161 xextendf(&msg1, "", ".");
1163 fp = sshkey_fingerprint(host_key,
1164 options.fingerprint_hash, SSH_FP_DEFAULT);
1165 ra = sshkey_fingerprint(host_key,
1166 options.fingerprint_hash, SSH_FP_RANDOMART);
1167 if (fp == NULL || ra == NULL)
1168 fatal_f("sshkey_fingerprint failed");
1169 xextendf(&msg1, "\n", "%s key fingerprint is %s.",
1171 if (options.visual_host_key)
1172 xextendf(&msg1, "\n", "%s", ra);
1173 if (options.verify_host_key_dns) {
1174 xextendf(&msg1, "\n",
1175 "%s host key fingerprint found in DNS.",
1176 matching_host_key_dns ?
1177 "Matching" : "No matching");
1179 /* msg2 informs for other names matching this key */
1180 if ((msg2 = other_hostkeys_message(host, ip, host_key,
1181 user_hostfiles, num_user_hostfiles,
1182 system_hostfiles, num_system_hostfiles)) != NULL)
1183 xextendf(&msg1, "\n", "%s", msg2);
1185 xextendf(&msg1, "\n",
1186 "Are you sure you want to continue connecting "
1187 "(yes/no/[fingerprint])? ");
1189 confirmed = confirm(msg1, fp);
1196 hostkey_trusted = 1; /* user explicitly confirmed */
1199 * If in "new" or "off" strict mode, add the key automatically
1200 * to the local known_hosts file.
1202 if (options.check_host_ip && ip_status == HOST_NEW) {
1203 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
1205 if (options.hash_known_hosts) {
1206 /* Add hash of host and IP separately */
1207 r = add_host_to_hostfile(user_hostfiles[0],
1208 host, host_key, options.hash_known_hosts) &&
1209 add_host_to_hostfile(user_hostfiles[0], ip,
1210 host_key, options.hash_known_hosts);
1212 /* Add unhashed "host,ip" */
1213 r = add_host_to_hostfile(user_hostfiles[0],
1215 options.hash_known_hosts);
1218 r = add_host_to_hostfile(user_hostfiles[0], host,
1219 host_key, options.hash_known_hosts);
1224 logit("Failed to add the host to the list of known "
1225 "hosts (%.500s).", user_hostfiles[0]);
1227 logit("Warning: Permanently added '%.200s' (%s) to the "
1228 "list of known hosts.", hostp, type);
1231 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1232 error("@ WARNING: REVOKED HOST KEY DETECTED! @");
1233 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1234 error("The %s host key for %s is marked as revoked.", type, host);
1235 error("This could mean that a stolen key is being used to");
1236 error("impersonate this host.");
1239 * If strict host key checking is in use, the user will have
1240 * to edit the key manually and we can only abort.
1242 if (options.strict_host_key_checking !=
1243 SSH_STRICT_HOSTKEY_OFF) {
1244 error("%s host key for %.200s was revoked and you have "
1245 "requested strict checking.", type, host);
1248 goto continue_unsafe;
1253 * This is only a debug() since it is valid to have
1254 * CAs with wildcard DNS matches that don't match
1255 * all hosts that one might visit.
1257 debug("Host certificate authority does not "
1258 "match %s in %s:%lu", CA_MARKER,
1259 host_found->file, host_found->line);
1262 if (readonly == ROQUIET)
1264 if (options.check_host_ip && host_ip_differ) {
1266 if (ip_status == HOST_NEW)
1267 key_msg = "is unknown";
1268 else if (ip_status == HOST_OK)
1269 key_msg = "is unchanged";
1271 key_msg = "has a different value";
1272 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1273 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
1274 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1275 error("The %s host key for %s has changed,", type, host);
1276 error("and the key for the corresponding IP address %s", ip);
1277 error("%s. This could either mean that", key_msg);
1278 error("DNS SPOOFING is happening or the IP address for the host");
1279 error("and its host key have changed at the same time.");
1280 if (ip_status != HOST_NEW)
1281 error("Offending key for IP in %s:%lu",
1282 ip_found->file, ip_found->line);
1284 /* The host key has changed. */
1285 warn_changed_key(host_key);
1286 if (num_user_hostfiles > 0 || num_system_hostfiles > 0) {
1287 error("Add correct host key in %.100s to get rid "
1288 "of this message.", num_user_hostfiles > 0 ?
1289 user_hostfiles[0] : system_hostfiles[0]);
1291 error("Offending %s key in %s:%lu",
1292 sshkey_type(host_found->key),
1293 host_found->file, host_found->line);
1296 * If strict host key checking is in use, the user will have
1297 * to edit the key manually and we can only abort.
1299 if (options.strict_host_key_checking !=
1300 SSH_STRICT_HOSTKEY_OFF) {
1301 error("Host key for %.200s has changed and you have "
1302 "requested strict checking.", host);
1308 * If strict host key checking has not been requested, allow
1309 * the connection but without MITM-able authentication or
1312 if (options.password_authentication) {
1313 error("Password authentication is disabled to avoid "
1314 "man-in-the-middle attacks.");
1315 options.password_authentication = 0;
1316 cancelled_forwarding = 1;
1318 if (options.kbd_interactive_authentication) {
1319 error("Keyboard-interactive authentication is disabled"
1320 " to avoid man-in-the-middle attacks.");
1321 options.kbd_interactive_authentication = 0;
1322 cancelled_forwarding = 1;
1324 if (options.forward_agent) {
1325 error("Agent forwarding is disabled to avoid "
1326 "man-in-the-middle attacks.");
1327 options.forward_agent = 0;
1328 cancelled_forwarding = 1;
1330 if (options.forward_x11) {
1331 error("X11 forwarding is disabled to avoid "
1332 "man-in-the-middle attacks.");
1333 options.forward_x11 = 0;
1334 cancelled_forwarding = 1;
1336 if (options.num_local_forwards > 0 ||
1337 options.num_remote_forwards > 0) {
1338 error("Port forwarding is disabled to avoid "
1339 "man-in-the-middle attacks.");
1340 options.num_local_forwards =
1341 options.num_remote_forwards = 0;
1342 cancelled_forwarding = 1;
1344 if (options.tun_open != SSH_TUNMODE_NO) {
1345 error("Tunnel forwarding is disabled to avoid "
1346 "man-in-the-middle attacks.");
1347 options.tun_open = SSH_TUNMODE_NO;
1348 cancelled_forwarding = 1;
1350 if (options.update_hostkeys != 0) {
1351 error("UpdateHostkeys is disabled because the host "
1352 "key is not trusted.");
1353 options.update_hostkeys = 0;
1355 if (options.exit_on_forward_failure && cancelled_forwarding)
1356 fatal("Error: forwarding disabled due to host key "
1360 * XXX Should permit the user to change to use the new id.
1361 * This could be done by converting the host key to an
1362 * identifying sentence, tell that the host identifies itself
1363 * by that sentence, and ask the user if they wish to
1364 * accept the authentication.
1368 fatal("internal error");
1372 if (options.check_host_ip && host_status != HOST_CHANGED &&
1373 ip_status == HOST_CHANGED) {
1374 snprintf(msg, sizeof(msg),
1375 "Warning: the %s host key for '%.200s' "
1376 "differs from the key for the IP address '%.128s'"
1377 "\nOffending key for IP in %s:%lu",
1378 type, host, ip, ip_found->file, ip_found->line);
1379 if (host_status == HOST_OK) {
1381 snprintf(msg + len, sizeof(msg) - len,
1382 "\nMatching host key in %s:%lu",
1383 host_found->file, host_found->line);
1385 if (options.strict_host_key_checking ==
1386 SSH_STRICT_HOSTKEY_ASK) {
1387 strlcat(msg, "\nAre you sure you want "
1388 "to continue connecting (yes/no)? ", sizeof(msg));
1389 if (!confirm(msg, NULL))
1391 } else if (options.strict_host_key_checking !=
1392 SSH_STRICT_HOSTKEY_OFF) {
1394 error("Exiting, you have requested strict checking.");
1401 if (!hostkey_trusted && options.update_hostkeys) {
1402 debug_f("hostkey not known or explicitly trusted: "
1403 "disabling UpdateHostkeys");
1404 options.update_hostkeys = 0;
1409 if (host_hostkeys != NULL)
1410 free_hostkeys(host_hostkeys);
1411 if (ip_hostkeys != NULL)
1412 free_hostkeys(ip_hostkeys);
1416 if (want_cert && host_status != HOST_REVOKED) {
1418 * No matching certificate. Downgrade cert to raw key and
1421 debug("No matching CA found. Retry with plain key");
1422 if ((r = sshkey_from_private(host_key, &raw_key)) != 0)
1423 fatal_fr(r, "decode key");
1424 if ((r = sshkey_drop_cert(raw_key)) != 0)
1425 fatal_r(r, "Couldn't drop certificate");
1429 sshkey_free(raw_key);
1432 if (host_hostkeys != NULL)
1433 free_hostkeys(host_hostkeys);
1434 if (ip_hostkeys != NULL)
1435 free_hostkeys(ip_hostkeys);
1439 /* returns 0 if key verifies or -1 if key does NOT verify */
1441 verify_host_key(char *host, struct sockaddr *hostaddr, struct sshkey *host_key,
1442 const struct ssh_conn_info *cinfo)
1445 int r = -1, flags = 0;
1446 char valid[64], *fp = NULL, *cafp = NULL;
1447 struct sshkey *plain = NULL;
1449 if ((fp = sshkey_fingerprint(host_key,
1450 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
1451 error_fr(r, "fingerprint host key");
1456 if (sshkey_is_cert(host_key)) {
1457 if ((cafp = sshkey_fingerprint(host_key->cert->signature_key,
1458 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
1459 error_fr(r, "fingerprint CA key");
1463 sshkey_format_cert_validity(host_key->cert,
1464 valid, sizeof(valid));
1465 debug("Server host certificate: %s %s, serial %llu "
1466 "ID \"%s\" CA %s %s valid %s",
1467 sshkey_ssh_name(host_key), fp,
1468 (unsigned long long)host_key->cert->serial,
1469 host_key->cert->key_id,
1470 sshkey_ssh_name(host_key->cert->signature_key), cafp,
1472 for (i = 0; i < host_key->cert->nprincipals; i++) {
1473 debug2("Server host certificate hostname: %s",
1474 host_key->cert->principals[i]);
1477 debug("Server host key: %s %s", sshkey_ssh_name(host_key), fp);
1480 if (sshkey_equal(previous_host_key, host_key)) {
1481 debug2_f("server host key %s %s matches cached key",
1482 sshkey_type(host_key), fp);
1487 /* Check in RevokedHostKeys file if specified */
1488 if (options.revoked_host_keys != NULL) {
1489 r = sshkey_check_revoked(host_key, options.revoked_host_keys);
1492 break; /* not revoked */
1493 case SSH_ERR_KEY_REVOKED:
1494 error("Host key %s %s revoked by file %s",
1495 sshkey_type(host_key), fp,
1496 options.revoked_host_keys);
1500 error_r(r, "Error checking host key %s %s in "
1501 "revoked keys file %s", sshkey_type(host_key),
1502 fp, options.revoked_host_keys);
1508 if (options.verify_host_key_dns) {
1510 * XXX certs are not yet supported for DNS, so downgrade
1511 * them and try the plain key.
1513 if ((r = sshkey_from_private(host_key, &plain)) != 0)
1515 if (sshkey_is_cert(plain))
1516 sshkey_drop_cert(plain);
1517 if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) {
1518 if (flags & DNS_VERIFY_FOUND) {
1519 if (options.verify_host_key_dns == 1 &&
1520 flags & DNS_VERIFY_MATCH &&
1521 flags & DNS_VERIFY_SECURE) {
1525 if (flags & DNS_VERIFY_MATCH) {
1526 matching_host_key_dns = 1;
1528 warn_changed_key(plain);
1529 error("Update the SSHFP RR in DNS "
1530 "with the new host key to get rid "
1531 "of this message.");
1536 r = check_host_key(host, cinfo, hostaddr, options.port, host_key,
1537 RDRW, 0, options.user_hostfiles, options.num_user_hostfiles,
1538 options.system_hostfiles, options.num_system_hostfiles,
1539 options.known_hosts_command);
1545 if (r == 0 && host_key != NULL) {
1546 sshkey_free(previous_host_key);
1547 r = sshkey_from_private(host_key, &previous_host_key);
1554 * Starts a dialog with the server, and authenticates the current user on the
1555 * server. This does not need any extra privileges. The basic connection
1556 * to the server must already have been established before this is called.
1557 * If login fails, this function prints an error and never returns.
1558 * This function does not require super-user privileges.
1561 ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
1562 struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms,
1563 const struct ssh_conn_info *cinfo)
1566 char *server_user, *local_user;
1569 local_user = xstrdup(pw->pw_name);
1570 server_user = options.user ? options.user : local_user;
1572 /* Convert the user-supplied hostname into all lowercase. */
1573 host = xstrdup(orighost);
1576 /* Exchange protocol version identification strings with the server. */
1577 if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0)
1578 sshpkt_fatal(ssh, r, "banner exchange");
1580 /* Put the connection into non-blocking mode. */
1581 ssh_packet_set_nonblocking(ssh);
1584 /* authenticate user */
1585 debug("Authenticating to %s:%d as '%s'", host, port, server_user);
1586 ssh_kex2(ssh, host, hostaddr, port, cinfo);
1587 ssh_userauth2(ssh, local_user, server_user, host, sensitive);
1592 /* print all known host keys for a given host, but skip keys of given type */
1594 show_other_keys(struct hostkeys *hostkeys, struct sshkey *key)
1606 const struct hostkey_entry *found;
1608 for (i = 0; type[i] != -1; i++) {
1609 if (type[i] == key->type)
1611 if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i],
1614 fp = sshkey_fingerprint(found->key,
1615 options.fingerprint_hash, SSH_FP_DEFAULT);
1616 ra = sshkey_fingerprint(found->key,
1617 options.fingerprint_hash, SSH_FP_RANDOMART);
1618 if (fp == NULL || ra == NULL)
1619 fatal_f("sshkey_fingerprint fail");
1620 logit("WARNING: %s key found for host %s\n"
1622 "%s key fingerprint %s.",
1623 sshkey_type(found->key),
1624 found->host, found->file, found->line,
1625 sshkey_type(found->key), fp);
1626 if (options.visual_host_key)
1636 warn_changed_key(struct sshkey *host_key)
1640 fp = sshkey_fingerprint(host_key, options.fingerprint_hash,
1643 fatal_f("sshkey_fingerprint fail");
1645 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1646 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1647 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1648 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1649 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
1650 error("It is also possible that a host key has just been changed.");
1651 error("The fingerprint for the %s key sent by the remote host is\n%s.",
1652 sshkey_type(host_key), fp);
1653 error("Please contact your system administrator.");
1659 * Execute a local command
1662 ssh_local_cmd(const char *args)
1667 void (*osighand)(int);
1669 if (!options.permit_local_command ||
1670 args == NULL || !*args)
1673 if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
1674 shell = _PATH_BSHELL;
1676 osighand = ssh_signal(SIGCHLD, SIG_DFL);
1679 ssh_signal(SIGPIPE, SIG_DFL);
1680 debug3("Executing %s -c \"%s\"", shell, args);
1681 execl(shell, shell, "-c", args, (char *)NULL);
1682 error("Couldn't execute %s -c \"%s\": %s",
1683 shell, args, strerror(errno));
1685 } else if (pid == -1)
1686 fatal("fork failed: %.100s", strerror(errno));
1687 while (waitpid(pid, &status, 0) == -1)
1689 fatal("Couldn't wait for child: %s", strerror(errno));
1690 ssh_signal(SIGCHLD, osighand);
1692 if (!WIFEXITED(status))
1695 return (WEXITSTATUS(status));
1699 maybe_add_key_to_agent(const char *authfile, struct sshkey *private,
1700 const char *comment, const char *passphrase)
1702 int auth_sock = -1, r;
1703 const char *skprovider = NULL;
1705 if (options.add_keys_to_agent == 0)
1708 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
1709 debug3("no authentication agent, not adding key");
1713 if (options.add_keys_to_agent == 2 &&
1714 !ask_permission("Add key %s (%s) to agent?", authfile, comment)) {
1715 debug3("user denied adding this key");
1719 if (sshkey_is_sk(private))
1720 skprovider = options.sk_provider;
1721 if ((r = ssh_add_identity_constrained(auth_sock, private,
1722 comment == NULL ? authfile : comment,
1723 options.add_keys_to_agent_lifespan,
1724 (options.add_keys_to_agent == 3), 0, skprovider, NULL, 0)) == 0)
1725 debug("identity added to agent: %s", authfile);
1727 debug("could not add identity to agent: %s (%d)", authfile, r);