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Darren Tuckera627d422013-06-02 07:31:17 +10001/* $OpenBSD: sshconnect.c,v 1.238 2013/05/17 00:13:14 djm Exp $ */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10002/*
Damien Miller95def091999-11-25 00:26:21 +11003 * Author: Tatu Ylonen <ylo@cs.hut.fi>
4 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11006 * Code to connect to a remote host, and to perform the client side of the
7 * login (authentication) dialog.
Damien Millere4340be2000-09-16 13:29:08 +11008 *
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".
Damien Miller95def091999-11-25 00:26:21 +110014 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100015
16#include "includes.h"
Damien Miller9cf6d072006-03-15 11:29:24 +110017
18#include <sys/types.h>
19#include <sys/wait.h>
Damien Millerf17883e2006-03-15 11:45:54 +110020#include <sys/stat.h>
Damien Miller8ec8c3e2006-07-10 20:35:38 +100021#include <sys/socket.h>
Damien Miller9aec9192006-08-05 10:57:45 +100022#ifdef HAVE_SYS_TIME_H
23# include <sys/time.h>
24#endif
Damien Miller8ec8c3e2006-07-10 20:35:38 +100025
26#include <netinet/in.h>
Darren Tucker46aa3e02006-09-02 15:32:40 +100027#include <arpa/inet.h>
Damien Miller03e20032006-03-15 11:16:59 +110028
Damien Millerc7b06362006-03-15 11:53:45 +110029#include <ctype.h>
Darren Tucker39972492006-07-12 22:22:46 +100030#include <errno.h>
Darren Tucker6e7fe1c2010-01-08 17:07:22 +110031#include <fcntl.h>
Damien Millerb8fe89c2006-07-24 14:51:00 +100032#include <netdb.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110033#ifdef HAVE_PATHS_H
Damien Miller03e20032006-03-15 11:16:59 +110034#include <paths.h>
Damien Miller6645e7a2006-03-15 14:42:54 +110035#endif
Damien Miller9f2abc42006-07-10 20:53:08 +100036#include <pwd.h>
Damien Miller9c0c31d2010-10-12 13:30:44 +110037#include <signal.h>
Damien Millerded319c2006-09-01 15:38:36 +100038#include <stdarg.h>
Damien Millera7a73ee2006-08-05 11:37:59 +100039#include <stdio.h>
Damien Millere7a1e5c2006-08-05 11:34:19 +100040#include <stdlib.h>
Damien Millere3476ed2006-07-24 14:13:33 +100041#include <string.h>
Damien Millere6b3b612006-07-24 14:01:23 +100042#include <unistd.h>
Damien Millerd4a8b7e1999-10-27 13:42:43 +100043
Damien Millerd4a8b7e1999-10-27 13:42:43 +100044#include "xmalloc.h"
Damien Millerd7834352006-08-05 12:39:39 +100045#include "key.h"
46#include "hostfile.h"
47#include "ssh.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100048#include "rsa.h"
Damien Miller1383bd82000-04-06 12:32:37 +100049#include "buffer.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100050#include "packet.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100051#include "uidswap.h"
52#include "compat.h"
Damien Miller450a7a12000-03-26 13:04:51 +100053#include "key.h"
Damien Millereba71ba2000-04-29 23:57:08 +100054#include "sshconnect.h"
Damien Miller450a7a12000-03-26 13:04:51 +100055#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000056#include "log.h"
57#include "readconf.h"
58#include "atomicio.h"
59#include "misc.h"
Damien Miller37876e92003-05-15 10:19:46 +100060#include "dns.h"
Darren Tuckerc5564e12009-06-21 18:53:53 +100061#include "roaming.h"
Damien Miller0a80ca12010-02-27 07:55:05 +110062#include "ssh2.h"
Damien Millerb7576772006-07-10 20:23:39 +100063#include "version.h"
Damien Miller37876e92003-05-15 10:19:46 +100064
Damien Millereba71ba2000-04-29 23:57:08 +100065char *client_version_string = NULL;
66char *server_version_string = NULL;
Damien Miller1383bd82000-04-06 12:32:37 +100067
Damien Millerc1af1d52005-11-05 15:08:57 +110068static int matching_host_key_dns = 0;
Damien Miller7392ae62003-06-11 22:05:25 +100069
Damien Millera41ccca2010-10-07 22:07:32 +110070static pid_t proxy_command_pid = 0;
71
Ben Lindstromf9c48842002-06-11 16:37:51 +000072/* import */
Damien Milleraae6c611999-12-06 11:47:28 +110073extern Options options;
Damien Miller34132e52000-01-14 15:45:46 +110074extern char *__progname;
Ben Lindstromf9c48842002-06-11 16:37:51 +000075extern uid_t original_real_uid;
76extern uid_t original_effective_uid;
Damien Milleraae6c611999-12-06 11:47:28 +110077
Damien Millerd925dcd2010-12-01 12:21:51 +110078static int show_other_keys(struct hostkeys *, Key *);
Damien Miller5a388972003-11-17 21:10:47 +110079static void warn_changed_key(Key *);
Ben Lindstrom3ed66402002-08-01 01:21:56 +000080
Damien Miller95def091999-11-25 00:26:21 +110081/*
82 * Connect to the given ssh server using a proxy command.
83 */
Ben Lindstrombba81212001-06-25 05:01:22 +000084static int
Ben Lindstromf9c48842002-06-11 16:37:51 +000085ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100086{
Damien Miller6476cad2005-06-16 13:18:34 +100087 char *command_string, *tmp;
Damien Miller95def091999-11-25 00:26:21 +110088 int pin[2], pout[2];
Damien Miller166fca82000-04-20 07:42:21 +100089 pid_t pid;
Damien Miller1d824ab2007-09-17 11:58:04 +100090 char *shell, strport[NI_MAXSERV];
91
Darren Tucker5d1d9542013-04-05 11:20:00 +110092 if (!strcmp(proxy_command, "-")) {
93 packet_set_connection(STDIN_FILENO, STDOUT_FILENO);
94 packet_set_timeout(options.server_alive_interval,
95 options.server_alive_count_max);
96 return 0;
97 }
98
Damien Miller38d9a962010-10-07 22:07:11 +110099 if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
Damien Miller1d824ab2007-09-17 11:58:04 +1000100 shell = _PATH_BSHELL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000101
Damien Miller95def091999-11-25 00:26:21 +1100102 /* Convert the port number into a string. */
Damien Miller34132e52000-01-14 15:45:46 +1100103 snprintf(strport, sizeof strport, "%hu", port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000104
Damien Miller8c4e18a2002-09-19 12:05:02 +1000105 /*
106 * Build the final command string in the buffer by making the
107 * appropriate substitutions to the given proxy command.
108 *
Damien Millera8e06ce2003-11-21 23:48:55 +1100109 * Use "exec" to avoid "sh -c" processes on some platforms
Damien Miller8c4e18a2002-09-19 12:05:02 +1000110 * (e.g. Solaris)
111 */
Damien Miller07d86be2006-03-26 14:19:21 +1100112 xasprintf(&tmp, "exec %s", proxy_command);
Damien Millerb1b17042010-04-16 15:54:19 +1000113 command_string = percent_expand(tmp, "h", host, "p", strport,
Damien Millerc617aa92010-04-18 08:08:20 +1000114 "r", options.user, (char *)NULL);
Darren Tuckera627d422013-06-02 07:31:17 +1000115 free(tmp);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000116
Damien Miller95def091999-11-25 00:26:21 +1100117 /* Create pipes for communicating with the proxy. */
118 if (pipe(pin) < 0 || pipe(pout) < 0)
119 fatal("Could not create pipes to communicate with the proxy: %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100120 strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000121
Damien Miller95def091999-11-25 00:26:21 +1100122 debug("Executing proxy command: %.500s", command_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000123
Damien Miller95def091999-11-25 00:26:21 +1100124 /* Fork and execute the proxy command. */
125 if ((pid = fork()) == 0) {
126 char *argv[10];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000127
Damien Miller95def091999-11-25 00:26:21 +1100128 /* Child. Permanently give up superuser privileges. */
Damien Miller2e5fe882006-06-13 13:10:00 +1000129 permanently_drop_suid(original_real_uid);
Damien Miller95def091999-11-25 00:26:21 +1100130
131 /* Redirect stdin and stdout. */
132 close(pin[1]);
133 if (pin[0] != 0) {
134 if (dup2(pin[0], 0) < 0)
135 perror("dup2 stdin");
136 close(pin[0]);
137 }
138 close(pout[0]);
139 if (dup2(pout[1], 1) < 0)
140 perror("dup2 stdout");
141 /* Cannot be 1 because pin allocated two descriptors. */
142 close(pout[1]);
143
144 /* Stderr is left as it is so that error messages get
145 printed on the user's terminal. */
Damien Miller1d824ab2007-09-17 11:58:04 +1000146 argv[0] = shell;
Damien Miller95def091999-11-25 00:26:21 +1100147 argv[1] = "-c";
148 argv[2] = command_string;
149 argv[3] = NULL;
150
151 /* Execute the proxy command. Note that we gave up any
152 extra privileges above. */
Damien Miller6fb6fd52011-01-16 23:17:45 +1100153 signal(SIGPIPE, SIG_DFL);
Kevin Stevesfcd5d602001-01-07 11:45:22 +0000154 execv(argv[0], argv);
155 perror(argv[0]);
Damien Miller95def091999-11-25 00:26:21 +1100156 exit(1);
157 }
158 /* Parent. */
159 if (pid < 0)
160 fatal("fork failed: %.100s", strerror(errno));
Damien Miller8c4e18a2002-09-19 12:05:02 +1000161 else
162 proxy_command_pid = pid; /* save pid to clean up later */
Damien Miller95def091999-11-25 00:26:21 +1100163
164 /* Close child side of the descriptors. */
165 close(pin[0]);
166 close(pout[1]);
167
168 /* Free the command name. */
Darren Tuckera627d422013-06-02 07:31:17 +1000169 free(command_string);
Damien Miller95def091999-11-25 00:26:21 +1100170
171 /* Set the connection file descriptors. */
172 packet_set_connection(pout[0], pin[1]);
Darren Tucker3fc464e2008-06-13 06:42:45 +1000173 packet_set_timeout(options.server_alive_interval,
174 options.server_alive_count_max);
Damien Miller95def091999-11-25 00:26:21 +1100175
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000176 /* Indicate OK return */
177 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000178}
179
Damien Millera41ccca2010-10-07 22:07:32 +1100180void
181ssh_kill_proxy_command(void)
182{
183 /*
184 * Send SIGHUP to proxy command if used. We don't wait() in
185 * case it hangs and instead rely on init to reap the child
186 */
187 if (proxy_command_pid > 1)
Damien Miller45fcdaa2010-10-07 22:07:58 +1100188 kill(proxy_command_pid, SIGHUP);
Damien Millera41ccca2010-10-07 22:07:32 +1100189}
190
Damien Miller95def091999-11-25 00:26:21 +1100191/*
192 * Creates a (possibly privileged) socket for use as the ssh connection.
193 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000194static int
Damien Miller2372ace2003-05-14 13:42:23 +1000195ssh_create_socket(int privileged, struct addrinfo *ai)
Damien Miller95def091999-11-25 00:26:21 +1100196{
Ben Lindstrome0f88042001-04-30 13:06:24 +0000197 int sock, gaierr;
198 struct addrinfo hints, *res;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000199
Damien Miller5428f641999-11-25 11:54:57 +1100200 /*
201 * If we are running as root and want to connect to a privileged
202 * port, bind our own socket to a privileged port.
203 */
Damien Miller95def091999-11-25 00:26:21 +1100204 if (privileged) {
205 int p = IPPORT_RESERVED - 1;
Ben Lindstromf9c48842002-06-11 16:37:51 +0000206 PRIV_START;
Damien Miller2372ace2003-05-14 13:42:23 +1000207 sock = rresvport_af(&p, ai->ai_family);
Ben Lindstromf9c48842002-06-11 16:37:51 +0000208 PRIV_END;
Damien Miller95def091999-11-25 00:26:21 +1100209 if (sock < 0)
Damien Miller2372ace2003-05-14 13:42:23 +1000210 error("rresvport: af=%d %.100s", ai->ai_family,
211 strerror(errno));
Damien Miller98c7ad62000-03-09 21:27:49 +1100212 else
213 debug("Allocated local port %d.", p);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000214 return sock;
Damien Miller95def091999-11-25 00:26:21 +1100215 }
Darren Tucker7bd98e72010-01-10 10:31:12 +1100216 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
Darren Tucker6e7fe1c2010-01-08 17:07:22 +1100217 if (sock < 0) {
Ben Lindstrome0f88042001-04-30 13:06:24 +0000218 error("socket: %.100s", strerror(errno));
Darren Tucker6e7fe1c2010-01-08 17:07:22 +1100219 return -1;
220 }
221 fcntl(sock, F_SETFD, FD_CLOEXEC);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000222
223 /* Bind the socket to an alternative local IP address */
224 if (options.bind_address == NULL)
225 return sock;
226
227 memset(&hints, 0, sizeof(hints));
Damien Miller2372ace2003-05-14 13:42:23 +1000228 hints.ai_family = ai->ai_family;
229 hints.ai_socktype = ai->ai_socktype;
230 hints.ai_protocol = ai->ai_protocol;
Ben Lindstrome0f88042001-04-30 13:06:24 +0000231 hints.ai_flags = AI_PASSIVE;
Darren Tucker30ac73b2008-06-13 04:46:45 +1000232 gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000233 if (gaierr) {
234 error("getaddrinfo: %s: %s", options.bind_address,
Darren Tucker4abde772007-12-29 02:43:51 +1100235 ssh_gai_strerror(gaierr));
Ben Lindstrome0f88042001-04-30 13:06:24 +0000236 close(sock);
237 return -1;
238 }
239 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
240 error("bind: %s: %s", options.bind_address, strerror(errno));
241 close(sock);
242 freeaddrinfo(res);
243 return -1;
244 }
245 freeaddrinfo(res);
Damien Miller95def091999-11-25 00:26:21 +1100246 return sock;
247}
248
Damien Millerb78d5eb2003-05-16 11:39:04 +1000249static int
250timeout_connect(int sockfd, const struct sockaddr *serv_addr,
Damien Miller67bd0622007-09-17 12:06:57 +1000251 socklen_t addrlen, int *timeoutp)
Damien Millerb78d5eb2003-05-16 11:39:04 +1000252{
253 fd_set *fdset;
Damien Miller67bd0622007-09-17 12:06:57 +1000254 struct timeval tv, t_start;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000255 socklen_t optlen;
Damien Miller07d86be2006-03-26 14:19:21 +1100256 int optval, rc, result = -1;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000257
Damien Miller67bd0622007-09-17 12:06:57 +1000258 gettimeofday(&t_start, NULL);
259
260 if (*timeoutp <= 0) {
261 result = connect(sockfd, serv_addr, addrlen);
262 goto done;
263 }
Damien Millerb78d5eb2003-05-16 11:39:04 +1000264
Damien Millerf6723f02004-01-27 21:21:27 +1100265 set_nonblock(sockfd);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000266 rc = connect(sockfd, serv_addr, addrlen);
Damien Millerf6723f02004-01-27 21:21:27 +1100267 if (rc == 0) {
268 unset_nonblock(sockfd);
Damien Miller67bd0622007-09-17 12:06:57 +1000269 result = 0;
270 goto done;
Damien Millerf6723f02004-01-27 21:21:27 +1100271 }
Damien Miller67bd0622007-09-17 12:06:57 +1000272 if (errno != EINPROGRESS) {
273 result = -1;
274 goto done;
275 }
Damien Millerb78d5eb2003-05-16 11:39:04 +1000276
Damien Miller07d86be2006-03-26 14:19:21 +1100277 fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
278 sizeof(fd_mask));
Damien Millerb78d5eb2003-05-16 11:39:04 +1000279 FD_SET(sockfd, fdset);
Damien Miller67bd0622007-09-17 12:06:57 +1000280 ms_to_timeval(&tv, *timeoutp);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000281
Darren Tucker47eede72005-03-14 23:08:12 +1100282 for (;;) {
Damien Millerb78d5eb2003-05-16 11:39:04 +1000283 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
284 if (rc != -1 || errno != EINTR)
285 break;
286 }
287
Darren Tucker47eede72005-03-14 23:08:12 +1100288 switch (rc) {
Damien Millerb78d5eb2003-05-16 11:39:04 +1000289 case 0:
290 /* Timed out */
291 errno = ETIMEDOUT;
Damien Miller08293fa2003-05-23 18:44:41 +1000292 break;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000293 case -1:
294 /* Select error */
Damien Millera8e06ce2003-11-21 23:48:55 +1100295 debug("select: %s", strerror(errno));
Damien Miller08293fa2003-05-23 18:44:41 +1000296 break;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000297 case 1:
298 /* Completed or failed */
299 optval = 0;
300 optlen = sizeof(optval);
Damien Millera8e06ce2003-11-21 23:48:55 +1100301 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
Darren Tuckerbd5361b2003-09-22 20:59:16 +1000302 &optlen) == -1) {
Damien Millera8e06ce2003-11-21 23:48:55 +1100303 debug("getsockopt: %s", strerror(errno));
Damien Miller08293fa2003-05-23 18:44:41 +1000304 break;
Darren Tuckerbd5361b2003-09-22 20:59:16 +1000305 }
Damien Millerb78d5eb2003-05-16 11:39:04 +1000306 if (optval != 0) {
307 errno = optval;
Damien Miller08293fa2003-05-23 18:44:41 +1000308 break;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000309 }
Damien Miller08293fa2003-05-23 18:44:41 +1000310 result = 0;
Damien Millerf6723f02004-01-27 21:21:27 +1100311 unset_nonblock(sockfd);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000312 break;
313 default:
314 /* Should not occur */
315 fatal("Bogus return (%d) from select()", rc);
316 }
317
Darren Tuckera627d422013-06-02 07:31:17 +1000318 free(fdset);
Damien Miller67bd0622007-09-17 12:06:57 +1000319
320 done:
321 if (result == 0 && *timeoutp > 0) {
322 ms_subtract_diff(&t_start, timeoutp);
323 if (*timeoutp <= 0) {
324 errno = ETIMEDOUT;
325 result = -1;
326 }
327 }
328
Damien Miller08293fa2003-05-23 18:44:41 +1000329 return (result);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000330}
331
Damien Miller95def091999-11-25 00:26:21 +1100332/*
Damien Miller34132e52000-01-14 15:45:46 +1100333 * Opens a TCP/IP connection to the remote server on the given host.
334 * The address of the remote host will be returned in hostaddr.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000335 * If port is 0, the default port will be used. If needpriv is true,
Damien Miller95def091999-11-25 00:26:21 +1100336 * a privileged port will be allocated to make the connection.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000337 * This requires super-user privileges if needpriv is true.
Damien Miller95def091999-11-25 00:26:21 +1100338 * Connection_attempts specifies the maximum number of tries (one per
339 * second). If proxy_command is non-NULL, it specifies the command (with %h
340 * and %p substituted for host and port, respectively) to use to contact
341 * the daemon.
342 */
343int
Damien Miller34132e52000-01-14 15:45:46 +1100344ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
Damien Miller67bd0622007-09-17 12:06:57 +1000345 u_short port, int family, int connection_attempts, int *timeout_ms,
346 int want_keepalive, int needpriv, const char *proxy_command)
Damien Miller95def091999-11-25 00:26:21 +1100347{
Damien Miller34132e52000-01-14 15:45:46 +1100348 int gaierr;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000349 int on = 1;
350 int sock = -1, attempt;
351 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
352 struct addrinfo hints, *ai, *aitop;
Damien Miller95def091999-11-25 00:26:21 +1100353
Ben Lindstrom064496f2002-12-23 02:04:22 +0000354 debug2("ssh_connect: needpriv %d", needpriv);
Damien Miller95def091999-11-25 00:26:21 +1100355
Damien Miller95def091999-11-25 00:26:21 +1100356 /* If a proxy command is given, connect using it. */
357 if (proxy_command != NULL)
Ben Lindstromf9c48842002-06-11 16:37:51 +0000358 return ssh_proxy_connect(host, port, proxy_command);
Damien Miller95def091999-11-25 00:26:21 +1100359
360 /* No proxy command. */
361
Damien Miller34132e52000-01-14 15:45:46 +1100362 memset(&hints, 0, sizeof(hints));
Damien Miller139d4cd2001-10-10 15:07:44 +1000363 hints.ai_family = family;
Damien Miller34132e52000-01-14 15:45:46 +1100364 hints.ai_socktype = SOCK_STREAM;
Ben Lindstrom5c385522002-06-23 21:23:20 +0000365 snprintf(strport, sizeof strport, "%u", port);
Damien Miller34132e52000-01-14 15:45:46 +1100366 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
Darren Tucker4abde772007-12-29 02:43:51 +1100367 fatal("%s: Could not resolve hostname %.100s: %s", __progname,
368 host, ssh_gai_strerror(gaierr));
Damien Miller95def091999-11-25 00:26:21 +1100369
Damien Miller56e5e6a2006-04-23 12:08:59 +1000370 for (attempt = 0; attempt < connection_attempts; attempt++) {
Damien Millerf4bcd102006-10-24 03:02:23 +1000371 if (attempt > 0) {
372 /* Sleep a moment before retrying. */
373 sleep(1);
Damien Miller95def091999-11-25 00:26:21 +1100374 debug("Trying again...");
Damien Millerf4bcd102006-10-24 03:02:23 +1000375 }
Damien Miller56e5e6a2006-04-23 12:08:59 +1000376 /*
377 * Loop through addresses for this host, and try each one in
378 * sequence until the connection succeeds.
379 */
Damien Miller34132e52000-01-14 15:45:46 +1100380 for (ai = aitop; ai; ai = ai->ai_next) {
381 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
382 continue;
383 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
384 ntop, sizeof(ntop), strport, sizeof(strport),
385 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
386 error("ssh_connect: getnameinfo failed");
387 continue;
388 }
389 debug("Connecting to %.200s [%.100s] port %s.",
390 host, ntop, strport);
Damien Miller95def091999-11-25 00:26:21 +1100391
Damien Miller34132e52000-01-14 15:45:46 +1100392 /* Create a socket for connecting. */
Damien Miller2372ace2003-05-14 13:42:23 +1000393 sock = ssh_create_socket(needpriv, ai);
Damien Miller34132e52000-01-14 15:45:46 +1100394 if (sock < 0)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000395 /* Any error is already output */
Damien Miller34132e52000-01-14 15:45:46 +1100396 continue;
Damien Miller95def091999-11-25 00:26:21 +1100397
Damien Millerb78d5eb2003-05-16 11:39:04 +1000398 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
Damien Miller67bd0622007-09-17 12:06:57 +1000399 timeout_ms) >= 0) {
Damien Miller34132e52000-01-14 15:45:46 +1100400 /* Successful connection. */
Ben Lindstroma3700052001-04-05 23:26:32 +0000401 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
Damien Miller95def091999-11-25 00:26:21 +1100402 break;
Damien Miller34132e52000-01-14 15:45:46 +1100403 } else {
Ben Lindstrom728aa7e2002-07-15 17:48:11 +0000404 debug("connect to address %s port %s: %s",
405 ntop, strport, strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100406 close(sock);
Damien Miller56e5e6a2006-04-23 12:08:59 +1000407 sock = -1;
Damien Miller95def091999-11-25 00:26:21 +1100408 }
Damien Miller95def091999-11-25 00:26:21 +1100409 }
Damien Miller56e5e6a2006-04-23 12:08:59 +1000410 if (sock != -1)
Damien Miller34132e52000-01-14 15:45:46 +1100411 break; /* Successful connection. */
Damien Miller95def091999-11-25 00:26:21 +1100412 }
Damien Miller34132e52000-01-14 15:45:46 +1100413
414 freeaddrinfo(aitop);
415
Damien Miller95def091999-11-25 00:26:21 +1100416 /* Return failure if we didn't get a successful connection. */
Damien Miller56e5e6a2006-04-23 12:08:59 +1000417 if (sock == -1) {
Darren Tuckerb2161e32005-01-20 11:00:46 +1100418 error("ssh: connect to host %s port %s: %s",
Ben Lindstroma6cd75c2002-07-11 04:00:19 +0000419 host, strport, strerror(errno));
Darren Tuckerb2161e32005-01-20 11:00:46 +1100420 return (-1);
Ben Lindstroma6cd75c2002-07-11 04:00:19 +0000421 }
Damien Miller95def091999-11-25 00:26:21 +1100422
423 debug("Connection established.");
424
Damien Miller12c150e2003-12-17 16:31:10 +1100425 /* Set SO_KEEPALIVE if requested. */
Damien Miller67bd0622007-09-17 12:06:57 +1000426 if (want_keepalive &&
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000427 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
428 sizeof(on)) < 0)
429 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100430
431 /* Set the connection. */
432 packet_set_connection(sock, sock);
Darren Tucker3fc464e2008-06-13 06:42:45 +1000433 packet_set_timeout(options.server_alive_interval,
434 options.server_alive_count_max);
Damien Miller95def091999-11-25 00:26:21 +1100435
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000436 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100437}
438
Darren Tucker00c15182012-09-06 21:21:56 +1000439static void
440send_client_banner(int connection_out, int minor1)
441{
Darren Tucker00c15182012-09-06 21:21:56 +1000442 /* Send our own protocol version identification. */
443 if (compat20) {
444 xasprintf(&client_version_string, "SSH-%d.%d-%.100s\r\n",
445 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION);
446 } else {
447 xasprintf(&client_version_string, "SSH-%d.%d-%.100s\n",
448 PROTOCOL_MAJOR_1, minor1, SSH_VERSION);
449 }
450 if (roaming_atomicio(vwrite, connection_out, client_version_string,
451 strlen(client_version_string)) != strlen(client_version_string))
452 fatal("write: %.100s", strerror(errno));
453 chop(client_version_string);
454 debug("Local version string %.100s", client_version_string);
455}
456
Damien Milleraae6c611999-12-06 11:47:28 +1100457/*
Damien Miller95def091999-11-25 00:26:21 +1100458 * Waits for the server identification string, and sends our own
459 * identification string.
460 */
Darren Tucker1cc55d72009-06-21 18:17:19 +1000461void
Damien Miller67bd0622007-09-17 12:06:57 +1000462ssh_exchange_identification(int timeout_ms)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000463{
Damien Miller95def091999-11-25 00:26:21 +1100464 char buf[256], remote_version[256]; /* must be same size! */
Damien Millereccb9de2005-06-17 12:59:34 +1000465 int remote_major, remote_minor, mismatch;
Damien Miller95def091999-11-25 00:26:21 +1100466 int connection_in = packet_get_connection_in();
467 int connection_out = packet_get_connection_out();
Darren Tucker00c15182012-09-06 21:21:56 +1000468 int minor1 = PROTOCOL_MINOR_1, client_banner_sent = 0;
Damien Miller1e88ea62006-07-10 20:15:56 +1000469 u_int i, n;
Damien Miller67bd0622007-09-17 12:06:57 +1000470 size_t len;
471 int fdsetsz, remaining, rc;
472 struct timeval t_start, t_remaining;
473 fd_set *fdset;
474
475 fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
476 fdset = xcalloc(1, fdsetsz);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000477
Darren Tucker00c15182012-09-06 21:21:56 +1000478 /*
479 * If we are SSH2-only then we can send the banner immediately and
480 * save a round-trip.
481 */
482 if (options.protocol == SSH_PROTO_2) {
483 enable_compat20();
484 send_client_banner(connection_out, 0);
485 client_banner_sent = 1;
486 }
487
Damien Millerb253cc42005-05-26 12:23:44 +1000488 /* Read other side's version identification. */
Damien Miller67bd0622007-09-17 12:06:57 +1000489 remaining = timeout_ms;
Damien Miller1e88ea62006-07-10 20:15:56 +1000490 for (n = 0;;) {
Damien Millerf6d9e222000-06-18 14:50:44 +1000491 for (i = 0; i < sizeof(buf) - 1; i++) {
Damien Miller67bd0622007-09-17 12:06:57 +1000492 if (timeout_ms > 0) {
493 gettimeofday(&t_start, NULL);
494 ms_to_timeval(&t_remaining, remaining);
495 FD_SET(connection_in, fdset);
496 rc = select(connection_in + 1, fdset, NULL,
497 fdset, &t_remaining);
498 ms_subtract_diff(&t_start, &remaining);
499 if (rc == 0 || remaining <= 0)
500 fatal("Connection timed out during "
501 "banner exchange");
502 if (rc == -1) {
503 if (errno == EINTR)
504 continue;
505 fatal("ssh_exchange_identification: "
506 "select: %s", strerror(errno));
507 }
508 }
509
Darren Tuckerc5564e12009-06-21 18:53:53 +1000510 len = roaming_atomicio(read, connection_in, &buf[i], 1);
Damien Millerb253cc42005-05-26 12:23:44 +1000511
Damien Miller46d38de2005-07-17 17:02:09 +1000512 if (len != 1 && errno == EPIPE)
Damien Miller67bd0622007-09-17 12:06:57 +1000513 fatal("ssh_exchange_identification: "
514 "Connection closed by remote host");
Damien Millerb253cc42005-05-26 12:23:44 +1000515 else if (len != 1)
Damien Miller67bd0622007-09-17 12:06:57 +1000516 fatal("ssh_exchange_identification: "
517 "read: %.100s", strerror(errno));
Damien Millerf6d9e222000-06-18 14:50:44 +1000518 if (buf[i] == '\r') {
519 buf[i] = '\n';
520 buf[i + 1] = 0;
521 continue; /**XXX wait for \n */
522 }
523 if (buf[i] == '\n') {
524 buf[i + 1] = 0;
525 break;
526 }
Damien Miller1e88ea62006-07-10 20:15:56 +1000527 if (++n > 65536)
Damien Miller67bd0622007-09-17 12:06:57 +1000528 fatal("ssh_exchange_identification: "
529 "No banner received");
Damien Miller95def091999-11-25 00:26:21 +1100530 }
Damien Millerf6d9e222000-06-18 14:50:44 +1000531 buf[sizeof(buf) - 1] = 0;
532 if (strncmp(buf, "SSH-", 4) == 0)
Damien Miller95def091999-11-25 00:26:21 +1100533 break;
Damien Millerf6d9e222000-06-18 14:50:44 +1000534 debug("ssh_exchange_identification: %s", buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000535 }
Damien Miller1383bd82000-04-06 12:32:37 +1000536 server_version_string = xstrdup(buf);
Darren Tuckera627d422013-06-02 07:31:17 +1000537 free(fdset);
Damien Miller95def091999-11-25 00:26:21 +1100538
Damien Miller5428f641999-11-25 11:54:57 +1100539 /*
540 * Check that the versions match. In future this might accept
541 * several versions and set appropriate flags to handle them.
542 */
Damien Miller1383bd82000-04-06 12:32:37 +1000543 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
544 &remote_major, &remote_minor, remote_version) != 3)
Damien Miller95def091999-11-25 00:26:21 +1100545 fatal("Bad remote protocol version identification: '%.100s'", buf);
546 debug("Remote protocol version %d.%d, remote software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100547 remote_major, remote_minor, remote_version);
Damien Miller95def091999-11-25 00:26:21 +1100548
Damien Miller1383bd82000-04-06 12:32:37 +1000549 compat_datafellows(remote_version);
Damien Miller78928792000-04-12 20:17:38 +1000550 mismatch = 0;
Damien Miller1383bd82000-04-06 12:32:37 +1000551
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000552 switch (remote_major) {
Damien Miller78928792000-04-12 20:17:38 +1000553 case 1:
554 if (remote_minor == 99 &&
555 (options.protocol & SSH_PROTO_2) &&
556 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
557 enable_compat20();
558 break;
Damien Miller95def091999-11-25 00:26:21 +1100559 }
Damien Miller78928792000-04-12 20:17:38 +1000560 if (!(options.protocol & SSH_PROTO_1)) {
561 mismatch = 1;
562 break;
563 }
564 if (remote_minor < 3) {
565 fatal("Remote machine has too old SSH software version.");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100566 } else if (remote_minor == 3 || remote_minor == 4) {
Damien Miller78928792000-04-12 20:17:38 +1000567 /* We speak 1.3, too. */
568 enable_compat13();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100569 minor1 = 3;
Damien Miller78928792000-04-12 20:17:38 +1000570 if (options.forward_agent) {
Damien Miller996acd22003-04-09 20:59:48 +1000571 logit("Agent forwarding disabled for protocol 1.3");
Damien Miller78928792000-04-12 20:17:38 +1000572 options.forward_agent = 0;
573 }
574 }
575 break;
576 case 2:
577 if (options.protocol & SSH_PROTO_2) {
578 enable_compat20();
579 break;
580 }
581 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000582 default:
Damien Miller78928792000-04-12 20:17:38 +1000583 mismatch = 1;
584 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000585 }
Damien Miller78928792000-04-12 20:17:38 +1000586 if (mismatch)
Damien Miller95def091999-11-25 00:26:21 +1100587 fatal("Protocol major versions differ: %d vs. %d",
Damien Miller78928792000-04-12 20:17:38 +1000588 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
589 remote_major);
Darren Tucker00c15182012-09-06 21:21:56 +1000590 if (!client_banner_sent)
591 send_client_banner(connection_out, minor1);
Damien Miller1383bd82000-04-06 12:32:37 +1000592 chop(server_version_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000593}
594
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000595/* defaults to 'no' */
Ben Lindstrombba81212001-06-25 05:01:22 +0000596static int
Damien Millere3980042001-10-10 15:02:03 +1000597confirm(const char *prompt)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000598{
Damien Miller49d795c2002-01-22 23:34:12 +1100599 const char *msg, *again = "Please type 'yes' or 'no': ";
600 char *p;
601 int ret = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000602
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000603 if (options.batch_mode)
604 return 0;
Damien Miller49d795c2002-01-22 23:34:12 +1100605 for (msg = prompt;;msg = again) {
606 p = read_passphrase(msg, RP_ECHO);
607 if (p == NULL ||
608 (p[0] == '\0') || (p[0] == '\n') ||
609 strncasecmp(p, "no", 2) == 0)
610 ret = 0;
Ben Lindstrom04f9af72002-07-04 00:03:56 +0000611 if (p && strncasecmp(p, "yes", 3) == 0)
Damien Miller49d795c2002-01-22 23:34:12 +1100612 ret = 1;
Darren Tuckera627d422013-06-02 07:31:17 +1000613 free(p);
Damien Miller49d795c2002-01-22 23:34:12 +1100614 if (ret != -1)
615 return ret;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000616 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000617}
618
Damien Miller0a80ca12010-02-27 07:55:05 +1100619static int
620check_host_cert(const char *host, const Key *host_key)
621{
622 const char *reason;
623
624 if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
625 error("%s", reason);
626 return 0;
627 }
Damien Miller4e270b02010-04-16 15:56:21 +1000628 if (buffer_len(&host_key->cert->critical) != 0) {
629 error("Certificate for %s contains unsupported "
630 "critical options(s)", host);
Damien Miller0a80ca12010-02-27 07:55:05 +1100631 return 0;
632 }
633 return 1;
634}
635
Damien Millerd925dcd2010-12-01 12:21:51 +1100636static int
637sockaddr_is_local(struct sockaddr *hostaddr)
638{
639 switch (hostaddr->sa_family) {
640 case AF_INET:
641 return (ntohl(((struct sockaddr_in *)hostaddr)->
642 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
643 case AF_INET6:
644 return IN6_IS_ADDR_LOOPBACK(
645 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
646 default:
647 return 0;
648 }
649}
650
651/*
652 * Prepare the hostname and ip address strings that are used to lookup
653 * host keys in known_hosts files. These may have a port number appended.
654 */
655void
656get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
657 u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
658{
659 char ntop[NI_MAXHOST];
660 socklen_t addrlen;
661
662 switch (hostaddr == NULL ? -1 : hostaddr->sa_family) {
663 case -1:
664 addrlen = 0;
665 break;
666 case AF_INET:
667 addrlen = sizeof(struct sockaddr_in);
668 break;
669 case AF_INET6:
670 addrlen = sizeof(struct sockaddr_in6);
671 break;
672 default:
673 addrlen = sizeof(struct sockaddr);
674 break;
675 }
676
677 /*
678 * We don't have the remote ip-address for connections
679 * using a proxy command
680 */
681 if (hostfile_ipaddr != NULL) {
682 if (options.proxy_command == NULL) {
683 if (getnameinfo(hostaddr, addrlen,
684 ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
685 fatal("check_host_key: getnameinfo failed");
686 *hostfile_ipaddr = put_host_port(ntop, port);
687 } else {
688 *hostfile_ipaddr = xstrdup("<no hostip for proxy "
689 "command>");
690 }
691 }
692
693 /*
694 * Allow the user to record the key under a different name or
695 * differentiate a non-standard port. This is useful for ssh
696 * tunneling over forwarded connections or if you run multiple
697 * sshd's on different ports on the same machine.
698 */
699 if (hostfile_hostname != NULL) {
700 if (options.host_key_alias != NULL) {
701 *hostfile_hostname = xstrdup(options.host_key_alias);
702 debug("using hostkeyalias: %s", *hostfile_hostname);
703 } else {
704 *hostfile_hostname = put_host_port(hostname, port);
705 }
706 }
707}
708
Damien Miller95def091999-11-25 00:26:21 +1100709/*
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000710 * check whether the supplied host key is valid, return -1 if the key
Damien Miller295ee632011-05-29 21:42:31 +1000711 * is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
Damien Miller95def091999-11-25 00:26:21 +1100712 */
Damien Millerda828392006-08-05 11:35:45 +1000713#define RDRW 0
714#define RDONLY 1
715#define ROQUIET 2
Ben Lindstrombba81212001-06-25 05:01:22 +0000716static int
Damien Millerda828392006-08-05 11:35:45 +1000717check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
Damien Miller295ee632011-05-29 21:42:31 +1000718 Key *host_key, int readonly,
719 char **user_hostfiles, u_int num_user_hostfiles,
720 char **system_hostfiles, u_int num_system_hostfiles)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000721{
Damien Miller95def091999-11-25 00:26:21 +1100722 HostStatus host_status;
723 HostStatus ip_status;
Damien Miller295ee632011-05-29 21:42:31 +1000724 Key *raw_key = NULL;
725 char *ip = NULL, *host = NULL;
726 char hostline[1000], *hostp, *fp, *ra;
Damien Miller49d795c2002-01-22 23:34:12 +1100727 char msg[1024];
Damien Miller295ee632011-05-29 21:42:31 +1000728 const char *type;
Damien Millerd925dcd2010-12-01 12:21:51 +1100729 const struct hostkey_entry *host_found, *ip_found;
Damien Miller295ee632011-05-29 21:42:31 +1000730 int len, cancelled_forwarding = 0;
731 int local = sockaddr_is_local(hostaddr);
732 int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
733 struct hostkeys *host_hostkeys, *ip_hostkeys;
734 u_int i;
Damien Miller34132e52000-01-14 15:45:46 +1100735
736 /*
737 * Force accepting of the host key for loopback/localhost. The
738 * problem is that if the home directory is NFS-mounted to multiple
739 * machines, localhost will refer to a different machine in each of
740 * them, and the user will get bogus HOST_CHANGED warnings. This
741 * essentially disables host authentication for localhost; however,
742 * this is probably not a real problem.
743 */
Ben Lindstrom3cecc9a2001-10-03 17:39:38 +0000744 if (options.no_host_authentication_for_localhost == 1 && local &&
745 options.host_key_alias == NULL) {
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000746 debug("Forcing accepting of host key for "
747 "loopback/localhost.");
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000748 return 0;
Damien Miller34132e52000-01-14 15:45:46 +1100749 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000750
Damien Milleraae6c611999-12-06 11:47:28 +1100751 /*
Damien Millerd925dcd2010-12-01 12:21:51 +1100752 * Prepare the hostname and address strings used for hostkey lookup.
753 * In some cases, these will have a port number appended.
Damien Milleraae6c611999-12-06 11:47:28 +1100754 */
Damien Millerd925dcd2010-12-01 12:21:51 +1100755 get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
Darren Tucker78913e02008-06-13 04:47:34 +1000756
757 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000758 * Turn off check_host_ip if the connection is to localhost, via proxy
759 * command or if we don't have a hostname to compare with
760 */
Darren Tuckerda345532006-07-10 23:04:19 +1000761 if (options.check_host_ip && (local ||
762 strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
Damien Milleraae6c611999-12-06 11:47:28 +1100763 options.check_host_ip = 0;
764
Damien Millerd925dcd2010-12-01 12:21:51 +1100765 host_hostkeys = init_hostkeys();
Damien Miller295ee632011-05-29 21:42:31 +1000766 for (i = 0; i < num_user_hostfiles; i++)
767 load_hostkeys(host_hostkeys, host, user_hostfiles[i]);
768 for (i = 0; i < num_system_hostfiles; i++)
769 load_hostkeys(host_hostkeys, host, system_hostfiles[i]);
Damien Millerd925dcd2010-12-01 12:21:51 +1100770
771 ip_hostkeys = NULL;
772 if (!want_cert && options.check_host_ip) {
773 ip_hostkeys = init_hostkeys();
Damien Miller295ee632011-05-29 21:42:31 +1000774 for (i = 0; i < num_user_hostfiles; i++)
775 load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]);
776 for (i = 0; i < num_system_hostfiles; i++)
777 load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000778 }
779
Damien Miller0a80ca12010-02-27 07:55:05 +1100780 retry:
Damien Millerd925dcd2010-12-01 12:21:51 +1100781 /* Reload these as they may have changed on cert->key downgrade */
Damien Miller0a80ca12010-02-27 07:55:05 +1100782 want_cert = key_is_cert(host_key);
783 type = key_type(host_key);
784
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000785 /*
Damien Miller788f2122005-11-05 15:14:59 +1100786 * Check if the host key is present in the user's list of known
Damien Miller5428f641999-11-25 11:54:57 +1100787 * hosts or in the systemwide list.
788 */
Damien Millerd925dcd2010-12-01 12:21:51 +1100789 host_status = check_key_in_hostkeys(host_hostkeys, host_key,
790 &host_found);
791
Damien Miller5428f641999-11-25 11:54:57 +1100792 /*
Damien Miller5428f641999-11-25 11:54:57 +1100793 * Also perform check for the ip address, skip the check if we are
Damien Miller0a80ca12010-02-27 07:55:05 +1100794 * localhost, looking for a certificate, or the hostname was an ip
795 * address to begin with.
Damien Miller5428f641999-11-25 11:54:57 +1100796 */
Damien Millerd925dcd2010-12-01 12:21:51 +1100797 if (!want_cert && ip_hostkeys != NULL) {
798 ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
799 &ip_found);
Damien Miller95def091999-11-25 00:26:21 +1100800 if (host_status == HOST_CHANGED &&
Damien Millerd925dcd2010-12-01 12:21:51 +1100801 (ip_status != HOST_CHANGED ||
802 (ip_found != NULL &&
803 !key_equal(ip_found->key, host_found->key))))
Damien Miller95def091999-11-25 00:26:21 +1100804 host_ip_differ = 1;
Damien Miller95def091999-11-25 00:26:21 +1100805 } else
806 ip_status = host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000807
Damien Miller95def091999-11-25 00:26:21 +1100808 switch (host_status) {
809 case HOST_OK:
810 /* The host is known and the key matches. */
Damien Miller0a80ca12010-02-27 07:55:05 +1100811 debug("Host '%.200s' is known and matches the %s host %s.",
812 host, type, want_cert ? "certificate" : "key");
Damien Millerd925dcd2010-12-01 12:21:51 +1100813 debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
814 host_found->file, host_found->line);
Damien Miller0a80ca12010-02-27 07:55:05 +1100815 if (want_cert && !check_host_cert(hostname, host_key))
816 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000817 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Miller0a80ca12010-02-27 07:55:05 +1100818 if (readonly || want_cert)
Damien Miller996acd22003-04-09 20:59:48 +1000819 logit("%s host key for IP address "
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000820 "'%.128s' not in list of known hosts.",
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000821 type, ip);
Damien Miller295ee632011-05-29 21:42:31 +1000822 else if (!add_host_to_hostfile(user_hostfiles[0], ip,
Damien Millere1776152005-03-01 21:47:37 +1100823 host_key, options.hash_known_hosts))
Damien Miller996acd22003-04-09 20:59:48 +1000824 logit("Failed to add the %s host key for IP "
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000825 "address '%.128s' to the list of known "
Damien Miller295ee632011-05-29 21:42:31 +1000826 "hosts (%.30s).", type, ip,
827 user_hostfiles[0]);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000828 else
Damien Miller996acd22003-04-09 20:59:48 +1000829 logit("Warning: Permanently added the %s host "
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000830 "key for IP address '%.128s' to the list "
831 "of known hosts.", type, ip);
Damien Miller10288242008-06-30 00:04:03 +1000832 } else if (options.visual_host_key) {
Darren Tucker9c16ac92008-06-13 04:40:35 +1000833 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
834 ra = key_fingerprint(host_key, SSH_FP_MD5,
835 SSH_FP_RANDOMART);
836 logit("Host key fingerprint is %s\n%s\n", fp, ra);
Darren Tuckera627d422013-06-02 07:31:17 +1000837 free(ra);
838 free(fp);
Damien Miller95def091999-11-25 00:26:21 +1100839 }
840 break;
841 case HOST_NEW:
Damien Millerda828392006-08-05 11:35:45 +1000842 if (options.host_key_alias == NULL && port != 0 &&
843 port != SSH_DEFAULT_PORT) {
844 debug("checking without port identifier");
Damien Millerece92c82008-11-03 19:25:03 +1100845 if (check_host_key(hostname, hostaddr, 0, host_key,
Damien Miller295ee632011-05-29 21:42:31 +1000846 ROQUIET, user_hostfiles, num_user_hostfiles,
847 system_hostfiles, num_system_hostfiles) == 0) {
Damien Millerda828392006-08-05 11:35:45 +1000848 debug("found matching key w/out port");
849 break;
850 }
851 }
Damien Miller0a80ca12010-02-27 07:55:05 +1100852 if (readonly || want_cert)
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000853 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100854 /* The host is new. */
855 if (options.strict_host_key_checking == 1) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000856 /*
857 * User has requested strict host key checking. We
858 * will not add the host key automatically. The only
859 * alternative left is to abort.
860 */
861 error("No %s host key is known for %.200s and you "
862 "have requested strict checking.", type, host);
863 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100864 } else if (options.strict_host_key_checking == 2) {
Damien Miller7392ae62003-06-11 22:05:25 +1000865 char msg1[1024], msg2[1024];
866
Damien Millerd925dcd2010-12-01 12:21:51 +1100867 if (show_other_keys(host_hostkeys, host_key))
Damien Miller7392ae62003-06-11 22:05:25 +1000868 snprintf(msg1, sizeof(msg1),
Damien Miller0dc1bef2005-07-17 17:22:45 +1000869 "\nbut keys of different type are already"
870 " known for this host.");
Damien Miller7392ae62003-06-11 22:05:25 +1000871 else
872 snprintf(msg1, sizeof(msg1), ".");
Damien Miller95def091999-11-25 00:26:21 +1100873 /* The default */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000874 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Darren Tucker9c16ac92008-06-13 04:40:35 +1000875 ra = key_fingerprint(host_key, SSH_FP_MD5,
876 SSH_FP_RANDOMART);
Damien Miller7392ae62003-06-11 22:05:25 +1000877 msg2[0] = '\0';
Damien Miller7392ae62003-06-11 22:05:25 +1000878 if (options.verify_host_key_dns) {
Damien Miller150b5572003-11-17 21:19:29 +1100879 if (matching_host_key_dns)
Damien Miller7392ae62003-06-11 22:05:25 +1000880 snprintf(msg2, sizeof(msg2),
881 "Matching host key fingerprint"
882 " found in DNS.\n");
883 else
884 snprintf(msg2, sizeof(msg2),
885 "No matching host key fingerprint"
886 " found in DNS.\n");
887 }
Damien Miller49d795c2002-01-22 23:34:12 +1100888 snprintf(msg, sizeof(msg),
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000889 "The authenticity of host '%.200s (%s)' can't be "
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000890 "established%s\n"
Damien Miller10288242008-06-30 00:04:03 +1000891 "%s key fingerprint is %s.%s%s\n%s"
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000892 "Are you sure you want to continue connecting "
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000893 "(yes/no)? ",
Damien Miller10288242008-06-30 00:04:03 +1000894 host, ip, msg1, type, fp,
895 options.visual_host_key ? "\n" : "",
896 options.visual_host_key ? ra : "",
897 msg2);
Darren Tuckera627d422013-06-02 07:31:17 +1000898 free(ra);
899 free(fp);
Damien Miller49d795c2002-01-22 23:34:12 +1100900 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000901 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100902 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000903 /*
904 * If not in strict mode, add the key automatically to the
905 * local known_hosts file.
906 */
Damien Miller1227d4c2005-03-02 12:06:51 +1100907 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Millerd925dcd2010-12-01 12:21:51 +1100908 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
Damien Miller1227d4c2005-03-02 12:06:51 +1100909 hostp = hostline;
910 if (options.hash_known_hosts) {
911 /* Add hash of host and IP separately */
Damien Miller295ee632011-05-29 21:42:31 +1000912 r = add_host_to_hostfile(user_hostfiles[0],
913 host, host_key, options.hash_known_hosts) &&
914 add_host_to_hostfile(user_hostfiles[0], ip,
Damien Miller1227d4c2005-03-02 12:06:51 +1100915 host_key, options.hash_known_hosts);
916 } else {
917 /* Add unhashed "host,ip" */
Damien Miller295ee632011-05-29 21:42:31 +1000918 r = add_host_to_hostfile(user_hostfiles[0],
Damien Miller1227d4c2005-03-02 12:06:51 +1100919 hostline, host_key,
920 options.hash_known_hosts);
921 }
922 } else {
Damien Miller295ee632011-05-29 21:42:31 +1000923 r = add_host_to_hostfile(user_hostfiles[0], host,
924 host_key, options.hash_known_hosts);
Damien Miller1227d4c2005-03-02 12:06:51 +1100925 hostp = host;
926 }
927
928 if (!r)
Damien Miller996acd22003-04-09 20:59:48 +1000929 logit("Failed to add the host to the list of known "
Damien Miller295ee632011-05-29 21:42:31 +1000930 "hosts (%.500s).", user_hostfiles[0]);
Damien Miller95def091999-11-25 00:26:21 +1100931 else
Damien Miller996acd22003-04-09 20:59:48 +1000932 logit("Warning: Permanently added '%.200s' (%s) to the "
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000933 "list of known hosts.", hostp, type);
Damien Miller95def091999-11-25 00:26:21 +1100934 break;
Damien Miller1aed65e2010-03-04 21:53:35 +1100935 case HOST_REVOKED:
936 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
937 error("@ WARNING: REVOKED HOST KEY DETECTED! @");
938 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
939 error("The %s host key for %s is marked as revoked.", type, host);
940 error("This could mean that a stolen key is being used to");
941 error("impersonate this host.");
942
943 /*
944 * If strict host key checking is in use, the user will have
945 * to edit the key manually and we can only abort.
946 */
947 if (options.strict_host_key_checking) {
948 error("%s host key for %.200s was revoked and you have "
949 "requested strict checking.", type, host);
950 goto fail;
951 }
952 goto continue_unsafe;
953
Damien Miller95def091999-11-25 00:26:21 +1100954 case HOST_CHANGED:
Damien Miller0a80ca12010-02-27 07:55:05 +1100955 if (want_cert) {
956 /*
957 * This is only a debug() since it is valid to have
958 * CAs with wildcard DNS matches that don't match
959 * all hosts that one might visit.
960 */
961 debug("Host certificate authority does not "
Damien Millerd925dcd2010-12-01 12:21:51 +1100962 "match %s in %s:%lu", CA_MARKER,
963 host_found->file, host_found->line);
Damien Miller0a80ca12010-02-27 07:55:05 +1100964 goto fail;
965 }
Damien Millerda828392006-08-05 11:35:45 +1000966 if (readonly == ROQUIET)
967 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100968 if (options.check_host_ip && host_ip_differ) {
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000969 char *key_msg;
Damien Miller95def091999-11-25 00:26:21 +1100970 if (ip_status == HOST_NEW)
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000971 key_msg = "is unknown";
Damien Miller95def091999-11-25 00:26:21 +1100972 else if (ip_status == HOST_OK)
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000973 key_msg = "is unchanged";
Damien Miller95def091999-11-25 00:26:21 +1100974 else
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000975 key_msg = "has a different value";
Damien Miller95def091999-11-25 00:26:21 +1100976 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
977 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
978 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millere247cc42000-05-07 12:03:14 +1000979 error("The %s host key for %s has changed,", type, host);
Darren Tuckerff4454d2008-06-13 10:21:51 +1000980 error("and the key for the corresponding IP address %s", ip);
Darren Tucker3f9fdc72004-06-22 12:56:01 +1000981 error("%s. This could either mean that", key_msg);
Damien Miller95def091999-11-25 00:26:21 +1100982 error("DNS SPOOFING is happening or the IP address for the host");
Ben Lindstrom46c16222000-12-22 01:43:59 +0000983 error("and its host key have changed at the same time.");
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000984 if (ip_status != HOST_NEW)
Damien Millerd925dcd2010-12-01 12:21:51 +1100985 error("Offending key for IP in %s:%lu",
986 ip_found->file, ip_found->line);
Damien Miller95def091999-11-25 00:26:21 +1100987 }
988 /* The host key has changed. */
Damien Miller5a388972003-11-17 21:10:47 +1100989 warn_changed_key(host_key);
Damien Miller95def091999-11-25 00:26:21 +1100990 error("Add correct host key in %.100s to get rid of this message.",
Damien Miller295ee632011-05-29 21:42:31 +1000991 user_hostfiles[0]);
Damien Millerd925dcd2010-12-01 12:21:51 +1100992 error("Offending %s key in %s:%lu", key_type(host_found->key),
993 host_found->file, host_found->line);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000994
Damien Miller5428f641999-11-25 11:54:57 +1100995 /*
996 * If strict host key checking is in use, the user will have
997 * to edit the key manually and we can only abort.
998 */
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000999 if (options.strict_host_key_checking) {
1000 error("%s host key for %.200s has changed and you have "
1001 "requested strict checking.", type, host);
1002 goto fail;
1003 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001004
Damien Miller1aed65e2010-03-04 21:53:35 +11001005 continue_unsafe:
Damien Miller5428f641999-11-25 11:54:57 +11001006 /*
1007 * If strict host key checking has not been requested, allow
Damien Miller941ac452003-06-04 20:31:53 +10001008 * the connection but without MITM-able authentication or
Damien Miller437edb92006-08-05 09:11:13 +10001009 * forwarding.
Damien Miller5428f641999-11-25 11:54:57 +11001010 */
Damien Miller95def091999-11-25 00:26:21 +11001011 if (options.password_authentication) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001012 error("Password authentication is disabled to avoid "
1013 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +11001014 options.password_authentication = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001015 cancelled_forwarding = 1;
Damien Miller95def091999-11-25 00:26:21 +11001016 }
Damien Miller941ac452003-06-04 20:31:53 +10001017 if (options.kbd_interactive_authentication) {
1018 error("Keyboard-interactive authentication is disabled"
1019 " to avoid man-in-the-middle attacks.");
1020 options.kbd_interactive_authentication = 0;
1021 options.challenge_response_authentication = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001022 cancelled_forwarding = 1;
Damien Miller941ac452003-06-04 20:31:53 +10001023 }
1024 if (options.challenge_response_authentication) {
1025 error("Challenge/response authentication is disabled"
1026 " to avoid man-in-the-middle attacks.");
1027 options.challenge_response_authentication = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001028 cancelled_forwarding = 1;
Damien Miller941ac452003-06-04 20:31:53 +10001029 }
Damien Miller95def091999-11-25 00:26:21 +11001030 if (options.forward_agent) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001031 error("Agent forwarding is disabled to avoid "
1032 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +11001033 options.forward_agent = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001034 cancelled_forwarding = 1;
Damien Miller95def091999-11-25 00:26:21 +11001035 }
Ben Lindstromc72745a2000-12-02 19:03:54 +00001036 if (options.forward_x11) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001037 error("X11 forwarding is disabled to avoid "
1038 "man-in-the-middle attacks.");
Ben Lindstromc72745a2000-12-02 19:03:54 +00001039 options.forward_x11 = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001040 cancelled_forwarding = 1;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001041 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001042 if (options.num_local_forwards > 0 ||
1043 options.num_remote_forwards > 0) {
1044 error("Port forwarding is disabled to avoid "
1045 "man-in-the-middle attacks.");
1046 options.num_local_forwards =
Damien Miller9f0f5c62001-12-21 14:45:46 +11001047 options.num_remote_forwards = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001048 cancelled_forwarding = 1;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001049 }
Damien Miller437edb92006-08-05 09:11:13 +10001050 if (options.tun_open != SSH_TUNMODE_NO) {
1051 error("Tunnel forwarding is disabled to avoid "
1052 "man-in-the-middle attacks.");
1053 options.tun_open = SSH_TUNMODE_NO;
Darren Tucker068e01f2008-07-02 22:33:55 +10001054 cancelled_forwarding = 1;
Damien Miller437edb92006-08-05 09:11:13 +10001055 }
Darren Tucker068e01f2008-07-02 22:33:55 +10001056 if (options.exit_on_forward_failure && cancelled_forwarding)
1057 fatal("Error: forwarding disabled due to host key "
1058 "check failure");
1059
Damien Miller5428f641999-11-25 11:54:57 +11001060 /*
1061 * XXX Should permit the user to change to use the new id.
1062 * This could be done by converting the host key to an
1063 * identifying sentence, tell that the host identifies itself
Darren Tuckere2b36742010-01-13 22:42:34 +11001064 * by that sentence, and ask the user if he/she wishes to
Damien Miller5428f641999-11-25 11:54:57 +11001065 * accept the authentication.
1066 */
Damien Miller95def091999-11-25 00:26:21 +11001067 break;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001068 case HOST_FOUND:
1069 fatal("internal error");
1070 break;
Damien Miller95def091999-11-25 00:26:21 +11001071 }
Ben Lindstromc72745a2000-12-02 19:03:54 +00001072
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001073 if (options.check_host_ip && host_status != HOST_CHANGED &&
1074 ip_status == HOST_CHANGED) {
Damien Miller49d795c2002-01-22 23:34:12 +11001075 snprintf(msg, sizeof(msg),
1076 "Warning: the %s host key for '%.200s' "
1077 "differs from the key for the IP address '%.128s'"
Damien Millerd925dcd2010-12-01 12:21:51 +11001078 "\nOffending key for IP in %s:%lu",
1079 type, host, ip, ip_found->file, ip_found->line);
Damien Miller49d795c2002-01-22 23:34:12 +11001080 if (host_status == HOST_OK) {
1081 len = strlen(msg);
1082 snprintf(msg + len, sizeof(msg) - len,
Damien Millerd925dcd2010-12-01 12:21:51 +11001083 "\nMatching host key in %s:%lu",
1084 host_found->file, host_found->line);
Damien Miller49d795c2002-01-22 23:34:12 +11001085 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001086 if (options.strict_host_key_checking == 1) {
Damien Millerab2db412003-06-02 19:09:13 +10001087 logit("%s", msg);
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001088 error("Exiting, you have requested strict checking.");
1089 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001090 } else if (options.strict_host_key_checking == 2) {
Damien Miller49d795c2002-01-22 23:34:12 +11001091 strlcat(msg, "\nAre you sure you want "
1092 "to continue connecting (yes/no)? ", sizeof(msg));
1093 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001094 goto fail;
Damien Miller49d795c2002-01-22 23:34:12 +11001095 } else {
Damien Millerab2db412003-06-02 19:09:13 +10001096 logit("%s", msg);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001097 }
1098 }
1099
Darren Tuckera627d422013-06-02 07:31:17 +10001100 free(ip);
1101 free(host);
Damien Millerd925dcd2010-12-01 12:21:51 +11001102 if (host_hostkeys != NULL)
1103 free_hostkeys(host_hostkeys);
1104 if (ip_hostkeys != NULL)
1105 free_hostkeys(ip_hostkeys);
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001106 return 0;
1107
1108fail:
Damien Miller1aed65e2010-03-04 21:53:35 +11001109 if (want_cert && host_status != HOST_REVOKED) {
Damien Miller0a80ca12010-02-27 07:55:05 +11001110 /*
1111 * No matching certificate. Downgrade cert to raw key and
1112 * search normally.
1113 */
1114 debug("No matching CA found. Retry with plain key");
1115 raw_key = key_from_private(host_key);
1116 if (key_drop_cert(raw_key) != 0)
1117 fatal("Couldn't drop certificate");
1118 host_key = raw_key;
1119 goto retry;
1120 }
1121 if (raw_key != NULL)
1122 key_free(raw_key);
Darren Tuckera627d422013-06-02 07:31:17 +10001123 free(ip);
1124 free(host);
Damien Millerd925dcd2010-12-01 12:21:51 +11001125 if (host_hostkeys != NULL)
1126 free_hostkeys(host_hostkeys);
1127 if (ip_hostkeys != NULL)
1128 free_hostkeys(ip_hostkeys);
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001129 return -1;
1130}
1131
Damien Miller37876e92003-05-15 10:19:46 +10001132/* returns 0 if key verifies or -1 if key does NOT verify */
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001133int
1134verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
1135{
Damien Miller150b5572003-11-17 21:19:29 +11001136 int flags = 0;
Damien Millerd925dcd2010-12-01 12:21:51 +11001137 char *fp;
1138
1139 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1140 debug("Server host key: %s %s", key_type(host_key), fp);
Darren Tuckera627d422013-06-02 07:31:17 +10001141 free(fp);
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001142
Damien Miller0a80ca12010-02-27 07:55:05 +11001143 /* XXX certs are not yet supported for DNS */
1144 if (!key_is_cert(host_key) && options.verify_host_key_dns &&
Damien Miller150b5572003-11-17 21:19:29 +11001145 verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
Damien Miller150b5572003-11-17 21:19:29 +11001146 if (flags & DNS_VERIFY_FOUND) {
1147
1148 if (options.verify_host_key_dns == 1 &&
1149 flags & DNS_VERIFY_MATCH &&
1150 flags & DNS_VERIFY_SECURE)
1151 return 0;
1152
1153 if (flags & DNS_VERIFY_MATCH) {
1154 matching_host_key_dns = 1;
1155 } else {
1156 warn_changed_key(host_key);
1157 error("Update the SSHFP RR in DNS with the new "
1158 "host key to get rid of this message.");
1159 }
Damien Miller37876e92003-05-15 10:19:46 +10001160 }
1161 }
Damien Miller37876e92003-05-15 10:19:46 +10001162
Damien Miller295ee632011-05-29 21:42:31 +10001163 return check_host_key(host, hostaddr, options.port, host_key, RDRW,
1164 options.user_hostfiles, options.num_user_hostfiles,
1165 options.system_hostfiles, options.num_system_hostfiles);
Damien Millera34a28b1999-12-14 10:47:15 +11001166}
Damien Miller037a0dc1999-12-07 15:38:31 +11001167
Damien Miller396691a2000-01-20 22:44:08 +11001168/*
1169 * Starts a dialog with the server, and authenticates the current user on the
1170 * server. This does not need any extra privileges. The basic connection
1171 * to the server must already have been established before this is called.
1172 * If login fails, this function prints an error and never returns.
1173 * This function does not require super-user privileges.
1174 */
1175void
Ben Lindstrom1bad2562002-06-06 19:57:33 +00001176ssh_login(Sensitive *sensitive, const char *orighost,
Damien Millerd925dcd2010-12-01 12:21:51 +11001177 struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
Damien Miller396691a2000-01-20 22:44:08 +11001178{
1179 char *host, *cp;
Damien Millereba71ba2000-04-29 23:57:08 +10001180 char *server_user, *local_user;
1181
Damien Millereba71ba2000-04-29 23:57:08 +10001182 local_user = xstrdup(pw->pw_name);
1183 server_user = options.user ? options.user : local_user;
Damien Miller396691a2000-01-20 22:44:08 +11001184
1185 /* Convert the user-supplied hostname into all lowercase. */
1186 host = xstrdup(orighost);
1187 for (cp = host; *cp; cp++)
1188 if (isupper(*cp))
Damien Miller1d2b6702006-03-26 14:09:54 +11001189 *cp = (char)tolower(*cp);
Damien Miller396691a2000-01-20 22:44:08 +11001190
1191 /* Exchange protocol version identification strings with the server. */
Damien Miller67bd0622007-09-17 12:06:57 +10001192 ssh_exchange_identification(timeout_ms);
Damien Miller396691a2000-01-20 22:44:08 +11001193
1194 /* Put the connection into non-blocking mode. */
1195 packet_set_nonblocking();
1196
Damien Miller396691a2000-01-20 22:44:08 +11001197 /* key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001198 /* authenticate user */
Damien Miller1383bd82000-04-06 12:32:37 +10001199 if (compat20) {
Damien Millerd925dcd2010-12-01 12:21:51 +11001200 ssh_kex2(host, hostaddr, port);
Ben Lindstrom1bad2562002-06-06 19:57:33 +00001201 ssh_userauth2(local_user, server_user, host, sensitive);
Damien Miller1383bd82000-04-06 12:32:37 +10001202 } else {
Damien Miller1383bd82000-04-06 12:32:37 +10001203 ssh_kex(host, hostaddr);
Ben Lindstrom1bad2562002-06-06 19:57:33 +00001204 ssh_userauth1(local_user, server_user, host, sensitive);
Damien Miller1383bd82000-04-06 12:32:37 +10001205 }
Darren Tuckera627d422013-06-02 07:31:17 +10001206 free(local_user);
Damien Miller396691a2000-01-20 22:44:08 +11001207}
Damien Miller79438cc2001-02-16 12:34:57 +11001208
1209void
1210ssh_put_password(char *password)
1211{
1212 int size;
1213 char *padded;
1214
Ben Lindstromd20d0f32001-03-10 17:22:20 +00001215 if (datafellows & SSH_BUG_PASSWORDPAD) {
Ben Lindstrom664408d2001-06-09 01:42:01 +00001216 packet_put_cstring(password);
Ben Lindstromd20d0f32001-03-10 17:22:20 +00001217 return;
1218 }
Damien Miller79438cc2001-02-16 12:34:57 +11001219 size = roundup(strlen(password) + 1, 32);
Damien Miller07d86be2006-03-26 14:19:21 +11001220 padded = xcalloc(1, size);
Damien Miller79438cc2001-02-16 12:34:57 +11001221 strlcpy(padded, password, size);
1222 packet_put_string(padded, size);
1223 memset(padded, 0, size);
Darren Tuckera627d422013-06-02 07:31:17 +10001224 free(padded);
Damien Miller79438cc2001-02-16 12:34:57 +11001225}
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001226
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001227/* print all known host keys for a given host, but skip keys of given type */
1228static int
Damien Millerd925dcd2010-12-01 12:21:51 +11001229show_other_keys(struct hostkeys *hostkeys, Key *key)
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001230{
Damien Millereb8b60e2010-08-31 22:41:14 +10001231 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, -1};
Damien Millerd925dcd2010-12-01 12:21:51 +11001232 int i, ret = 0;
1233 char *fp, *ra;
1234 const struct hostkey_entry *found;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001235
1236 for (i = 0; type[i] != -1; i++) {
1237 if (type[i] == key->type)
1238 continue;
Damien Millerd925dcd2010-12-01 12:21:51 +11001239 if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001240 continue;
Damien Millerd925dcd2010-12-01 12:21:51 +11001241 fp = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
1242 ra = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_RANDOMART);
1243 logit("WARNING: %s key found for host %s\n"
1244 "in %s:%lu\n"
1245 "%s key fingerprint %s.",
1246 key_type(found->key),
1247 found->host, found->file, found->line,
1248 key_type(found->key), fp);
1249 if (options.visual_host_key)
1250 logit("%s", ra);
Darren Tuckera627d422013-06-02 07:31:17 +10001251 free(ra);
1252 free(fp);
Damien Millerd925dcd2010-12-01 12:21:51 +11001253 ret = 1;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001254 }
Damien Millerd925dcd2010-12-01 12:21:51 +11001255 return ret;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001256}
Damien Miller5a388972003-11-17 21:10:47 +11001257
1258static void
1259warn_changed_key(Key *host_key)
1260{
1261 char *fp;
Damien Miller5a388972003-11-17 21:10:47 +11001262
1263 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
1264
1265 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1266 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1267 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1268 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1269 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
Damien Miller05c89972011-01-06 22:42:04 +11001270 error("It is also possible that a host key has just been changed.");
Damien Miller5a388972003-11-17 21:10:47 +11001271 error("The fingerprint for the %s key sent by the remote host is\n%s.",
Damien Miller05c89972011-01-06 22:42:04 +11001272 key_type(host_key), fp);
Damien Miller5a388972003-11-17 21:10:47 +11001273 error("Please contact your system administrator.");
1274
Darren Tuckera627d422013-06-02 07:31:17 +10001275 free(fp);
Damien Miller5a388972003-11-17 21:10:47 +11001276}
Damien Millerd27b9472005-12-13 19:29:02 +11001277
1278/*
1279 * Execute a local command
1280 */
1281int
1282ssh_local_cmd(const char *args)
1283{
1284 char *shell;
1285 pid_t pid;
1286 int status;
Damien Millered3a8eb2011-01-07 10:02:52 +11001287 void (*osighand)(int);
Damien Millerd27b9472005-12-13 19:29:02 +11001288
1289 if (!options.permit_local_command ||
1290 args == NULL || !*args)
1291 return (1);
1292
Damien Miller38d9a962010-10-07 22:07:11 +11001293 if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
Damien Millerd27b9472005-12-13 19:29:02 +11001294 shell = _PATH_BSHELL;
1295
Damien Millered3a8eb2011-01-07 10:02:52 +11001296 osighand = signal(SIGCHLD, SIG_DFL);
Damien Millerd27b9472005-12-13 19:29:02 +11001297 pid = fork();
1298 if (pid == 0) {
Damien Miller6fb6fd52011-01-16 23:17:45 +11001299 signal(SIGPIPE, SIG_DFL);
Damien Millerd27b9472005-12-13 19:29:02 +11001300 debug3("Executing %s -c \"%s\"", shell, args);
1301 execl(shell, shell, "-c", args, (char *)NULL);
1302 error("Couldn't execute %s -c \"%s\": %s",
1303 shell, args, strerror(errno));
1304 _exit(1);
1305 } else if (pid == -1)
1306 fatal("fork failed: %.100s", strerror(errno));
1307 while (waitpid(pid, &status, 0) == -1)
1308 if (errno != EINTR)
1309 fatal("Couldn't wait for child: %s", strerror(errno));
Damien Millered3a8eb2011-01-07 10:02:52 +11001310 signal(SIGCHLD, osighand);
Damien Millerd27b9472005-12-13 19:29:02 +11001311
1312 if (!WIFEXITED(status))
1313 return (1);
1314
1315 return (WEXITSTATUS(status));
1316}