blob: 96b91ce1ab4b8a6555de8476f0a70701da125c6f [file] [log] [blame]
deraadt@openbsd.org9136ec12016-09-12 01:22:38 +00001/* $OpenBSD: sshconnect.c,v 1.272 2016/09/12 01:22:38 deraadt 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"
Damien Miller7acefbb2014-07-18 14:11:24 +100057#include "misc.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000058#include "readconf.h"
59#include "atomicio.h"
Damien Miller37876e92003-05-15 10:19:46 +100060#include "dns.h"
Damien Miller1262b662013-08-21 02:44:24 +100061#include "monitor_fdpass.h"
Damien Miller0a80ca12010-02-27 07:55:05 +110062#include "ssh2.h"
Damien Millerb7576772006-07-10 20:23:39 +100063#include "version.h"
djm@openbsd.org5e39a492014-12-04 02:24:32 +000064#include "authfile.h"
65#include "ssherr.h"
jcs@openbsd.orgf361df42015-11-15 22:26:49 +000066#include "authfd.h"
Damien Miller37876e92003-05-15 10:19:46 +100067
Damien Millereba71ba2000-04-29 23:57:08 +100068char *client_version_string = NULL;
69char *server_version_string = NULL;
Damien Miller6b37fbb2014-07-04 08:59:24 +100070Key *previous_host_key = NULL;
Damien Miller1383bd82000-04-06 12:32:37 +100071
Damien Millerc1af1d52005-11-05 15:08:57 +110072static int matching_host_key_dns = 0;
Damien Miller7392ae62003-06-11 22:05:25 +100073
Damien Millera41ccca2010-10-07 22:07:32 +110074static pid_t proxy_command_pid = 0;
75
Ben Lindstromf9c48842002-06-11 16:37:51 +000076/* import */
Damien Milleraae6c611999-12-06 11:47:28 +110077extern Options options;
Damien Miller34132e52000-01-14 15:45:46 +110078extern char *__progname;
Ben Lindstromf9c48842002-06-11 16:37:51 +000079extern uid_t original_real_uid;
80extern uid_t original_effective_uid;
Damien Milleraae6c611999-12-06 11:47:28 +110081
Damien Millerd925dcd2010-12-01 12:21:51 +110082static int show_other_keys(struct hostkeys *, Key *);
Damien Miller5a388972003-11-17 21:10:47 +110083static void warn_changed_key(Key *);
Ben Lindstrom3ed66402002-08-01 01:21:56 +000084
Damien Miller1262b662013-08-21 02:44:24 +100085/* Expand a proxy command */
86static char *
87expand_proxy_command(const char *proxy_command, const char *user,
88 const char *host, int port)
89{
90 char *tmp, *ret, strport[NI_MAXSERV];
91
Damien Miller0faf7472013-10-17 11:47:23 +110092 snprintf(strport, sizeof strport, "%d", port);
Damien Miller1262b662013-08-21 02:44:24 +100093 xasprintf(&tmp, "exec %s", proxy_command);
94 ret = percent_expand(tmp, "h", host, "p", strport,
95 "r", options.user, (char *)NULL);
96 free(tmp);
97 return ret;
98}
99
100/*
101 * Connect to the given ssh server using a proxy command that passes a
102 * a connected fd back to us.
103 */
104static int
105ssh_proxy_fdpass_connect(const char *host, u_short port,
106 const char *proxy_command)
107{
108 char *command_string;
109 int sp[2], sock;
110 pid_t pid;
111 char *shell;
112
113 if ((shell = getenv("SHELL")) == NULL)
114 shell = _PATH_BSHELL;
115
116 if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0)
117 fatal("Could not create socketpair to communicate with "
118 "proxy dialer: %.100s", strerror(errno));
119
120 command_string = expand_proxy_command(proxy_command, options.user,
121 host, port);
122 debug("Executing proxy dialer command: %.500s", command_string);
123
124 /* Fork and execute the proxy command. */
125 if ((pid = fork()) == 0) {
126 char *argv[10];
127
128 /* Child. Permanently give up superuser privileges. */
129 permanently_drop_suid(original_real_uid);
130
131 close(sp[1]);
132 /* Redirect stdin and stdout. */
133 if (sp[0] != 0) {
134 if (dup2(sp[0], 0) < 0)
135 perror("dup2 stdin");
136 }
137 if (sp[0] != 1) {
138 if (dup2(sp[0], 1) < 0)
139 perror("dup2 stdout");
140 }
141 if (sp[0] >= 2)
142 close(sp[0]);
143
144 /*
145 * Stderr is left as it is so that error messages get
146 * printed on the user's terminal.
147 */
148 argv[0] = shell;
149 argv[1] = "-c";
150 argv[2] = command_string;
151 argv[3] = NULL;
152
153 /*
154 * Execute the proxy command.
155 * Note that we gave up any extra privileges above.
156 */
157 execv(argv[0], argv);
158 perror(argv[0]);
159 exit(1);
160 }
161 /* Parent. */
162 if (pid < 0)
163 fatal("fork failed: %.100s", strerror(errno));
164 close(sp[0]);
165 free(command_string);
166
167 if ((sock = mm_receive_fd(sp[1])) == -1)
168 fatal("proxy dialer did not pass back a connection");
markus@openbsd.orgfc77ccd2016-01-14 22:56:56 +0000169 close(sp[1]);
Damien Miller1262b662013-08-21 02:44:24 +1000170
171 while (waitpid(pid, NULL, 0) == -1)
172 if (errno != EINTR)
173 fatal("Couldn't wait for child: %s", strerror(errno));
174
175 /* Set the connection file descriptors. */
176 packet_set_connection(sock, sock);
Damien Miller1262b662013-08-21 02:44:24 +1000177
178 return 0;
179}
180
Damien Miller95def091999-11-25 00:26:21 +1100181/*
182 * Connect to the given ssh server using a proxy command.
183 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000184static int
Ben Lindstromf9c48842002-06-11 16:37:51 +0000185ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000186{
Damien Miller1262b662013-08-21 02:44:24 +1000187 char *command_string;
Damien Miller95def091999-11-25 00:26:21 +1100188 int pin[2], pout[2];
Damien Miller166fca82000-04-20 07:42:21 +1000189 pid_t pid;
Damien Miller1262b662013-08-21 02:44:24 +1000190 char *shell;
Damien Miller1d824ab2007-09-17 11:58:04 +1000191
Damien Miller38d9a962010-10-07 22:07:11 +1100192 if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
Damien Miller1d824ab2007-09-17 11:58:04 +1000193 shell = _PATH_BSHELL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000194
Damien Miller95def091999-11-25 00:26:21 +1100195 /* Create pipes for communicating with the proxy. */
196 if (pipe(pin) < 0 || pipe(pout) < 0)
197 fatal("Could not create pipes to communicate with the proxy: %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100198 strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000199
Damien Miller1262b662013-08-21 02:44:24 +1000200 command_string = expand_proxy_command(proxy_command, options.user,
201 host, port);
Damien Miller95def091999-11-25 00:26:21 +1100202 debug("Executing proxy command: %.500s", command_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000203
Damien Miller95def091999-11-25 00:26:21 +1100204 /* Fork and execute the proxy command. */
205 if ((pid = fork()) == 0) {
206 char *argv[10];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000207
Damien Miller95def091999-11-25 00:26:21 +1100208 /* Child. Permanently give up superuser privileges. */
Damien Miller2e5fe882006-06-13 13:10:00 +1000209 permanently_drop_suid(original_real_uid);
Damien Miller95def091999-11-25 00:26:21 +1100210
211 /* Redirect stdin and stdout. */
212 close(pin[1]);
213 if (pin[0] != 0) {
214 if (dup2(pin[0], 0) < 0)
215 perror("dup2 stdin");
216 close(pin[0]);
217 }
218 close(pout[0]);
219 if (dup2(pout[1], 1) < 0)
220 perror("dup2 stdout");
221 /* Cannot be 1 because pin allocated two descriptors. */
222 close(pout[1]);
223
224 /* Stderr is left as it is so that error messages get
225 printed on the user's terminal. */
Damien Miller1d824ab2007-09-17 11:58:04 +1000226 argv[0] = shell;
Damien Miller95def091999-11-25 00:26:21 +1100227 argv[1] = "-c";
228 argv[2] = command_string;
229 argv[3] = NULL;
230
231 /* Execute the proxy command. Note that we gave up any
232 extra privileges above. */
Damien Miller6fb6fd52011-01-16 23:17:45 +1100233 signal(SIGPIPE, SIG_DFL);
Kevin Stevesfcd5d602001-01-07 11:45:22 +0000234 execv(argv[0], argv);
235 perror(argv[0]);
Damien Miller95def091999-11-25 00:26:21 +1100236 exit(1);
237 }
238 /* Parent. */
239 if (pid < 0)
240 fatal("fork failed: %.100s", strerror(errno));
Damien Miller8c4e18a2002-09-19 12:05:02 +1000241 else
242 proxy_command_pid = pid; /* save pid to clean up later */
Damien Miller95def091999-11-25 00:26:21 +1100243
244 /* Close child side of the descriptors. */
245 close(pin[0]);
246 close(pout[1]);
247
248 /* Free the command name. */
Darren Tuckera627d422013-06-02 07:31:17 +1000249 free(command_string);
Damien Miller95def091999-11-25 00:26:21 +1100250
251 /* Set the connection file descriptors. */
252 packet_set_connection(pout[0], pin[1]);
253
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000254 /* Indicate OK return */
255 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000256}
257
Damien Millera41ccca2010-10-07 22:07:32 +1100258void
259ssh_kill_proxy_command(void)
260{
261 /*
262 * Send SIGHUP to proxy command if used. We don't wait() in
263 * case it hangs and instead rely on init to reap the child
264 */
265 if (proxy_command_pid > 1)
Damien Miller45fcdaa2010-10-07 22:07:58 +1100266 kill(proxy_command_pid, SIGHUP);
Damien Millera41ccca2010-10-07 22:07:32 +1100267}
268
Damien Miller95def091999-11-25 00:26:21 +1100269/*
270 * Creates a (possibly privileged) socket for use as the ssh connection.
271 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000272static int
Damien Miller2372ace2003-05-14 13:42:23 +1000273ssh_create_socket(int privileged, struct addrinfo *ai)
Damien Miller95def091999-11-25 00:26:21 +1100274{
Darren Tuckere6e52f82013-10-10 10:28:07 +1100275 int sock, r, gaierr;
Damien Millerd1a7a9c2014-02-07 09:24:33 +1100276 struct addrinfo hints, *res = NULL;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000277
Darren Tucker7bd98e72010-01-10 10:31:12 +1100278 sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
Darren Tucker6e7fe1c2010-01-08 17:07:22 +1100279 if (sock < 0) {
Darren Tuckere6e52f82013-10-10 10:28:07 +1100280 error("socket: %s", strerror(errno));
Darren Tucker6e7fe1c2010-01-08 17:07:22 +1100281 return -1;
282 }
283 fcntl(sock, F_SETFD, FD_CLOEXEC);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000284
285 /* Bind the socket to an alternative local IP address */
Darren Tuckere6e52f82013-10-10 10:28:07 +1100286 if (options.bind_address == NULL && !privileged)
Ben Lindstrome0f88042001-04-30 13:06:24 +0000287 return sock;
288
Damien Millerd1a7a9c2014-02-07 09:24:33 +1100289 if (options.bind_address) {
290 memset(&hints, 0, sizeof(hints));
291 hints.ai_family = ai->ai_family;
292 hints.ai_socktype = ai->ai_socktype;
293 hints.ai_protocol = ai->ai_protocol;
294 hints.ai_flags = AI_PASSIVE;
295 gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
296 if (gaierr) {
297 error("getaddrinfo: %s: %s", options.bind_address,
298 ssh_gai_strerror(gaierr));
299 close(sock);
300 return -1;
301 }
Ben Lindstrome0f88042001-04-30 13:06:24 +0000302 }
Darren Tuckere6e52f82013-10-10 10:28:07 +1100303 /*
304 * If we are running as root and want to connect to a privileged
305 * port, bind our own socket to a privileged port.
306 */
307 if (privileged) {
308 PRIV_START;
Damien Millerd1a7a9c2014-02-07 09:24:33 +1100309 r = bindresvport_sa(sock, res ? res->ai_addr : NULL);
Darren Tuckere6e52f82013-10-10 10:28:07 +1100310 PRIV_END;
311 if (r < 0) {
312 error("bindresvport_sa: af=%d %s", ai->ai_family,
313 strerror(errno));
314 goto fail;
315 }
316 } else {
317 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
318 error("bind: %s: %s", options.bind_address,
319 strerror(errno));
320 fail:
321 close(sock);
322 freeaddrinfo(res);
323 return -1;
324 }
Ben Lindstrome0f88042001-04-30 13:06:24 +0000325 }
Damien Millerd1a7a9c2014-02-07 09:24:33 +1100326 if (res != NULL)
327 freeaddrinfo(res);
Damien Miller95def091999-11-25 00:26:21 +1100328 return sock;
329}
330
Damien Millerb78d5eb2003-05-16 11:39:04 +1000331static int
332timeout_connect(int sockfd, const struct sockaddr *serv_addr,
Damien Miller67bd0622007-09-17 12:06:57 +1000333 socklen_t addrlen, int *timeoutp)
Damien Millerb78d5eb2003-05-16 11:39:04 +1000334{
335 fd_set *fdset;
Damien Miller67bd0622007-09-17 12:06:57 +1000336 struct timeval tv, t_start;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000337 socklen_t optlen;
Damien Miller07d86be2006-03-26 14:19:21 +1100338 int optval, rc, result = -1;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000339
Damien Miller67bd0622007-09-17 12:06:57 +1000340 gettimeofday(&t_start, NULL);
341
342 if (*timeoutp <= 0) {
343 result = connect(sockfd, serv_addr, addrlen);
344 goto done;
345 }
Damien Millerb78d5eb2003-05-16 11:39:04 +1000346
Damien Millerf6723f02004-01-27 21:21:27 +1100347 set_nonblock(sockfd);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000348 rc = connect(sockfd, serv_addr, addrlen);
Damien Millerf6723f02004-01-27 21:21:27 +1100349 if (rc == 0) {
350 unset_nonblock(sockfd);
Damien Miller67bd0622007-09-17 12:06:57 +1000351 result = 0;
352 goto done;
Damien Millerf6723f02004-01-27 21:21:27 +1100353 }
Damien Miller67bd0622007-09-17 12:06:57 +1000354 if (errno != EINPROGRESS) {
355 result = -1;
356 goto done;
357 }
Damien Millerb78d5eb2003-05-16 11:39:04 +1000358
deraadt@openbsd.orgce445b02015-08-20 22:32:42 +0000359 fdset = xcalloc(howmany(sockfd + 1, NFDBITS),
Damien Miller07d86be2006-03-26 14:19:21 +1100360 sizeof(fd_mask));
Damien Millerb78d5eb2003-05-16 11:39:04 +1000361 FD_SET(sockfd, fdset);
Damien Miller67bd0622007-09-17 12:06:57 +1000362 ms_to_timeval(&tv, *timeoutp);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000363
Darren Tucker47eede72005-03-14 23:08:12 +1100364 for (;;) {
Damien Millerb78d5eb2003-05-16 11:39:04 +1000365 rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
366 if (rc != -1 || errno != EINTR)
367 break;
368 }
369
Darren Tucker47eede72005-03-14 23:08:12 +1100370 switch (rc) {
Damien Millerb78d5eb2003-05-16 11:39:04 +1000371 case 0:
372 /* Timed out */
373 errno = ETIMEDOUT;
Damien Miller08293fa2003-05-23 18:44:41 +1000374 break;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000375 case -1:
376 /* Select error */
Damien Millera8e06ce2003-11-21 23:48:55 +1100377 debug("select: %s", strerror(errno));
Damien Miller08293fa2003-05-23 18:44:41 +1000378 break;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000379 case 1:
380 /* Completed or failed */
381 optval = 0;
382 optlen = sizeof(optval);
Damien Millera8e06ce2003-11-21 23:48:55 +1100383 if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
Darren Tuckerbd5361b2003-09-22 20:59:16 +1000384 &optlen) == -1) {
Damien Millera8e06ce2003-11-21 23:48:55 +1100385 debug("getsockopt: %s", strerror(errno));
Damien Miller08293fa2003-05-23 18:44:41 +1000386 break;
Darren Tuckerbd5361b2003-09-22 20:59:16 +1000387 }
Damien Millerb78d5eb2003-05-16 11:39:04 +1000388 if (optval != 0) {
389 errno = optval;
Damien Miller08293fa2003-05-23 18:44:41 +1000390 break;
Damien Millerb78d5eb2003-05-16 11:39:04 +1000391 }
Damien Miller08293fa2003-05-23 18:44:41 +1000392 result = 0;
Damien Millerf6723f02004-01-27 21:21:27 +1100393 unset_nonblock(sockfd);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000394 break;
395 default:
396 /* Should not occur */
397 fatal("Bogus return (%d) from select()", rc);
398 }
399
Darren Tuckera627d422013-06-02 07:31:17 +1000400 free(fdset);
Damien Miller67bd0622007-09-17 12:06:57 +1000401
402 done:
403 if (result == 0 && *timeoutp > 0) {
404 ms_subtract_diff(&t_start, timeoutp);
405 if (*timeoutp <= 0) {
406 errno = ETIMEDOUT;
407 result = -1;
408 }
409 }
410
Damien Miller08293fa2003-05-23 18:44:41 +1000411 return (result);
Damien Millerb78d5eb2003-05-16 11:39:04 +1000412}
413
Damien Miller95def091999-11-25 00:26:21 +1100414/*
Damien Miller34132e52000-01-14 15:45:46 +1100415 * Opens a TCP/IP connection to the remote server on the given host.
416 * The address of the remote host will be returned in hostaddr.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000417 * If port is 0, the default port will be used. If needpriv is true,
Damien Miller95def091999-11-25 00:26:21 +1100418 * a privileged port will be allocated to make the connection.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000419 * This requires super-user privileges if needpriv is true.
Damien Miller95def091999-11-25 00:26:21 +1100420 * Connection_attempts specifies the maximum number of tries (one per
421 * second). If proxy_command is non-NULL, it specifies the command (with %h
422 * and %p substituted for host and port, respectively) to use to contact
423 * the daemon.
424 */
Damien Miller0faf7472013-10-17 11:47:23 +1100425static int
426ssh_connect_direct(const char *host, struct addrinfo *aitop,
427 struct sockaddr_storage *hostaddr, u_short port, int family,
428 int connection_attempts, int *timeout_ms, int want_keepalive, int needpriv)
Damien Miller95def091999-11-25 00:26:21 +1100429{
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000430 int on = 1;
431 int sock = -1, attempt;
432 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
Damien Miller0faf7472013-10-17 11:47:23 +1100433 struct addrinfo *ai;
Damien Miller95def091999-11-25 00:26:21 +1100434
djm@openbsd.org46152af2015-09-04 04:55:24 +0000435 debug2("%s: needpriv %d", __func__, needpriv);
djm@openbsd.org88b6fcd2015-11-19 08:23:27 +0000436 memset(ntop, 0, sizeof(ntop));
437 memset(strport, 0, sizeof(strport));
Damien Miller95def091999-11-25 00:26:21 +1100438
Damien Miller56e5e6a2006-04-23 12:08:59 +1000439 for (attempt = 0; attempt < connection_attempts; attempt++) {
Damien Millerf4bcd102006-10-24 03:02:23 +1000440 if (attempt > 0) {
441 /* Sleep a moment before retrying. */
442 sleep(1);
Damien Miller95def091999-11-25 00:26:21 +1100443 debug("Trying again...");
Damien Millerf4bcd102006-10-24 03:02:23 +1000444 }
Damien Miller56e5e6a2006-04-23 12:08:59 +1000445 /*
446 * Loop through addresses for this host, and try each one in
447 * sequence until the connection succeeds.
448 */
Damien Miller34132e52000-01-14 15:45:46 +1100449 for (ai = aitop; ai; ai = ai->ai_next) {
Damien Miller0faf7472013-10-17 11:47:23 +1100450 if (ai->ai_family != AF_INET &&
451 ai->ai_family != AF_INET6)
Damien Miller34132e52000-01-14 15:45:46 +1100452 continue;
453 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
454 ntop, sizeof(ntop), strport, sizeof(strport),
455 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
djm@openbsd.org46152af2015-09-04 04:55:24 +0000456 error("%s: getnameinfo failed", __func__);
Damien Miller34132e52000-01-14 15:45:46 +1100457 continue;
458 }
459 debug("Connecting to %.200s [%.100s] port %s.",
460 host, ntop, strport);
Damien Miller95def091999-11-25 00:26:21 +1100461
Damien Miller34132e52000-01-14 15:45:46 +1100462 /* Create a socket for connecting. */
Damien Miller2372ace2003-05-14 13:42:23 +1000463 sock = ssh_create_socket(needpriv, ai);
Damien Miller34132e52000-01-14 15:45:46 +1100464 if (sock < 0)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000465 /* Any error is already output */
Damien Miller34132e52000-01-14 15:45:46 +1100466 continue;
Damien Miller95def091999-11-25 00:26:21 +1100467
Damien Millerb78d5eb2003-05-16 11:39:04 +1000468 if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
Damien Miller67bd0622007-09-17 12:06:57 +1000469 timeout_ms) >= 0) {
Damien Miller34132e52000-01-14 15:45:46 +1100470 /* Successful connection. */
Ben Lindstroma3700052001-04-05 23:26:32 +0000471 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
Damien Miller95def091999-11-25 00:26:21 +1100472 break;
Damien Miller34132e52000-01-14 15:45:46 +1100473 } else {
Ben Lindstrom728aa7e2002-07-15 17:48:11 +0000474 debug("connect to address %s port %s: %s",
475 ntop, strport, strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100476 close(sock);
Damien Miller56e5e6a2006-04-23 12:08:59 +1000477 sock = -1;
Damien Miller95def091999-11-25 00:26:21 +1100478 }
Damien Miller95def091999-11-25 00:26:21 +1100479 }
Damien Miller56e5e6a2006-04-23 12:08:59 +1000480 if (sock != -1)
Damien Miller34132e52000-01-14 15:45:46 +1100481 break; /* Successful connection. */
Damien Miller95def091999-11-25 00:26:21 +1100482 }
Damien Miller34132e52000-01-14 15:45:46 +1100483
Damien Miller95def091999-11-25 00:26:21 +1100484 /* Return failure if we didn't get a successful connection. */
Damien Miller56e5e6a2006-04-23 12:08:59 +1000485 if (sock == -1) {
Darren Tuckerb2161e32005-01-20 11:00:46 +1100486 error("ssh: connect to host %s port %s: %s",
Ben Lindstroma6cd75c2002-07-11 04:00:19 +0000487 host, strport, strerror(errno));
Darren Tuckerb2161e32005-01-20 11:00:46 +1100488 return (-1);
Ben Lindstroma6cd75c2002-07-11 04:00:19 +0000489 }
Damien Miller95def091999-11-25 00:26:21 +1100490
491 debug("Connection established.");
492
Damien Miller12c150e2003-12-17 16:31:10 +1100493 /* Set SO_KEEPALIVE if requested. */
Damien Miller67bd0622007-09-17 12:06:57 +1000494 if (want_keepalive &&
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000495 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
496 sizeof(on)) < 0)
497 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100498
499 /* Set the connection. */
500 packet_set_connection(sock, sock);
501
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000502 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100503}
504
Damien Miller0faf7472013-10-17 11:47:23 +1100505int
506ssh_connect(const char *host, struct addrinfo *addrs,
507 struct sockaddr_storage *hostaddr, u_short port, int family,
508 int connection_attempts, int *timeout_ms, int want_keepalive, int needpriv)
509{
510 if (options.proxy_command == NULL) {
511 return ssh_connect_direct(host, addrs, hostaddr, port, family,
512 connection_attempts, timeout_ms, want_keepalive, needpriv);
513 } else if (strcmp(options.proxy_command, "-") == 0) {
514 packet_set_connection(STDIN_FILENO, STDOUT_FILENO);
515 return 0; /* Always succeeds */
516 } else if (options.proxy_use_fdpass) {
517 return ssh_proxy_fdpass_connect(host, port,
518 options.proxy_command);
519 }
520 return ssh_proxy_connect(host, port, options.proxy_command);
521}
522
Darren Tucker00c15182012-09-06 21:21:56 +1000523static void
524send_client_banner(int connection_out, int minor1)
525{
Darren Tucker00c15182012-09-06 21:21:56 +1000526 /* Send our own protocol version identification. */
527 if (compat20) {
528 xasprintf(&client_version_string, "SSH-%d.%d-%.100s\r\n",
529 PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION);
530 } else {
531 xasprintf(&client_version_string, "SSH-%d.%d-%.100s\n",
532 PROTOCOL_MAJOR_1, minor1, SSH_VERSION);
533 }
markus@openbsd.orga3068632016-01-14 16:17:39 +0000534 if (atomicio(vwrite, connection_out, client_version_string,
Darren Tucker00c15182012-09-06 21:21:56 +1000535 strlen(client_version_string)) != strlen(client_version_string))
536 fatal("write: %.100s", strerror(errno));
537 chop(client_version_string);
538 debug("Local version string %.100s", client_version_string);
539}
540
Damien Milleraae6c611999-12-06 11:47:28 +1100541/*
Damien Miller95def091999-11-25 00:26:21 +1100542 * Waits for the server identification string, and sends our own
543 * identification string.
544 */
Darren Tucker1cc55d72009-06-21 18:17:19 +1000545void
Damien Miller67bd0622007-09-17 12:06:57 +1000546ssh_exchange_identification(int timeout_ms)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000547{
Damien Miller95def091999-11-25 00:26:21 +1100548 char buf[256], remote_version[256]; /* must be same size! */
Damien Millereccb9de2005-06-17 12:59:34 +1000549 int remote_major, remote_minor, mismatch;
Damien Miller95def091999-11-25 00:26:21 +1100550 int connection_in = packet_get_connection_in();
551 int connection_out = packet_get_connection_out();
Darren Tucker00c15182012-09-06 21:21:56 +1000552 int minor1 = PROTOCOL_MINOR_1, client_banner_sent = 0;
Damien Miller1e88ea62006-07-10 20:15:56 +1000553 u_int i, n;
Damien Miller67bd0622007-09-17 12:06:57 +1000554 size_t len;
555 int fdsetsz, remaining, rc;
556 struct timeval t_start, t_remaining;
557 fd_set *fdset;
558
559 fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
560 fdset = xcalloc(1, fdsetsz);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000561
Darren Tucker00c15182012-09-06 21:21:56 +1000562 /*
563 * If we are SSH2-only then we can send the banner immediately and
564 * save a round-trip.
565 */
566 if (options.protocol == SSH_PROTO_2) {
567 enable_compat20();
568 send_client_banner(connection_out, 0);
569 client_banner_sent = 1;
570 }
571
Damien Millerb253cc42005-05-26 12:23:44 +1000572 /* Read other side's version identification. */
Damien Miller67bd0622007-09-17 12:06:57 +1000573 remaining = timeout_ms;
Damien Miller1e88ea62006-07-10 20:15:56 +1000574 for (n = 0;;) {
Damien Millerf6d9e222000-06-18 14:50:44 +1000575 for (i = 0; i < sizeof(buf) - 1; i++) {
Damien Miller67bd0622007-09-17 12:06:57 +1000576 if (timeout_ms > 0) {
577 gettimeofday(&t_start, NULL);
578 ms_to_timeval(&t_remaining, remaining);
579 FD_SET(connection_in, fdset);
580 rc = select(connection_in + 1, fdset, NULL,
581 fdset, &t_remaining);
582 ms_subtract_diff(&t_start, &remaining);
583 if (rc == 0 || remaining <= 0)
584 fatal("Connection timed out during "
585 "banner exchange");
586 if (rc == -1) {
587 if (errno == EINTR)
588 continue;
589 fatal("ssh_exchange_identification: "
590 "select: %s", strerror(errno));
591 }
592 }
593
markus@openbsd.orga3068632016-01-14 16:17:39 +0000594 len = atomicio(read, connection_in, &buf[i], 1);
Damien Millerb253cc42005-05-26 12:23:44 +1000595
Damien Miller46d38de2005-07-17 17:02:09 +1000596 if (len != 1 && errno == EPIPE)
Damien Miller67bd0622007-09-17 12:06:57 +1000597 fatal("ssh_exchange_identification: "
598 "Connection closed by remote host");
Damien Millerb253cc42005-05-26 12:23:44 +1000599 else if (len != 1)
Damien Miller67bd0622007-09-17 12:06:57 +1000600 fatal("ssh_exchange_identification: "
601 "read: %.100s", strerror(errno));
Damien Millerf6d9e222000-06-18 14:50:44 +1000602 if (buf[i] == '\r') {
603 buf[i] = '\n';
604 buf[i + 1] = 0;
605 continue; /**XXX wait for \n */
606 }
607 if (buf[i] == '\n') {
608 buf[i + 1] = 0;
609 break;
610 }
Damien Miller1e88ea62006-07-10 20:15:56 +1000611 if (++n > 65536)
Damien Miller67bd0622007-09-17 12:06:57 +1000612 fatal("ssh_exchange_identification: "
613 "No banner received");
Damien Miller95def091999-11-25 00:26:21 +1100614 }
Damien Millerf6d9e222000-06-18 14:50:44 +1000615 buf[sizeof(buf) - 1] = 0;
616 if (strncmp(buf, "SSH-", 4) == 0)
Damien Miller95def091999-11-25 00:26:21 +1100617 break;
Damien Millerf6d9e222000-06-18 14:50:44 +1000618 debug("ssh_exchange_identification: %s", buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000619 }
Damien Miller1383bd82000-04-06 12:32:37 +1000620 server_version_string = xstrdup(buf);
Darren Tuckera627d422013-06-02 07:31:17 +1000621 free(fdset);
Damien Miller95def091999-11-25 00:26:21 +1100622
Damien Miller5428f641999-11-25 11:54:57 +1100623 /*
624 * Check that the versions match. In future this might accept
625 * several versions and set appropriate flags to handle them.
626 */
Damien Miller1383bd82000-04-06 12:32:37 +1000627 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
628 &remote_major, &remote_minor, remote_version) != 3)
Damien Miller95def091999-11-25 00:26:21 +1100629 fatal("Bad remote protocol version identification: '%.100s'", buf);
630 debug("Remote protocol version %d.%d, remote software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100631 remote_major, remote_minor, remote_version);
Damien Miller95def091999-11-25 00:26:21 +1100632
markus@openbsd.org48b3b2b2015-01-19 20:20:20 +0000633 active_state->compat = compat_datafellows(remote_version);
Damien Miller78928792000-04-12 20:17:38 +1000634 mismatch = 0;
Damien Miller1383bd82000-04-06 12:32:37 +1000635
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000636 switch (remote_major) {
Damien Miller78928792000-04-12 20:17:38 +1000637 case 1:
638 if (remote_minor == 99 &&
639 (options.protocol & SSH_PROTO_2) &&
640 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
641 enable_compat20();
642 break;
Damien Miller95def091999-11-25 00:26:21 +1100643 }
Damien Miller78928792000-04-12 20:17:38 +1000644 if (!(options.protocol & SSH_PROTO_1)) {
645 mismatch = 1;
646 break;
647 }
648 if (remote_minor < 3) {
649 fatal("Remote machine has too old SSH software version.");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100650 } else if (remote_minor == 3 || remote_minor == 4) {
Damien Miller78928792000-04-12 20:17:38 +1000651 /* We speak 1.3, too. */
652 enable_compat13();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100653 minor1 = 3;
Damien Miller78928792000-04-12 20:17:38 +1000654 if (options.forward_agent) {
Damien Miller996acd22003-04-09 20:59:48 +1000655 logit("Agent forwarding disabled for protocol 1.3");
Damien Miller78928792000-04-12 20:17:38 +1000656 options.forward_agent = 0;
657 }
658 }
659 break;
660 case 2:
661 if (options.protocol & SSH_PROTO_2) {
662 enable_compat20();
663 break;
664 }
665 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000666 default:
Damien Miller78928792000-04-12 20:17:38 +1000667 mismatch = 1;
668 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000669 }
Damien Miller78928792000-04-12 20:17:38 +1000670 if (mismatch)
Damien Miller95def091999-11-25 00:26:21 +1100671 fatal("Protocol major versions differ: %d vs. %d",
Damien Miller78928792000-04-12 20:17:38 +1000672 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
673 remote_major);
Damien Miller58cd63b2014-01-10 10:59:24 +1100674 if ((datafellows & SSH_BUG_DERIVEKEY) != 0)
675 fatal("Server version \"%.100s\" uses unsafe key agreement; "
676 "refusing connection", remote_version);
Damien Miller324541e2013-12-31 12:25:40 +1100677 if ((datafellows & SSH_BUG_RSASIGMD5) != 0)
678 logit("Server version \"%.100s\" uses unsafe RSA signature "
679 "scheme; disabling use of RSA keys", remote_version);
Darren Tucker00c15182012-09-06 21:21:56 +1000680 if (!client_banner_sent)
681 send_client_banner(connection_out, minor1);
Damien Miller1383bd82000-04-06 12:32:37 +1000682 chop(server_version_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000683}
684
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000685/* defaults to 'no' */
Ben Lindstrombba81212001-06-25 05:01:22 +0000686static int
Damien Millere3980042001-10-10 15:02:03 +1000687confirm(const char *prompt)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000688{
Damien Miller49d795c2002-01-22 23:34:12 +1100689 const char *msg, *again = "Please type 'yes' or 'no': ";
690 char *p;
691 int ret = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000692
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000693 if (options.batch_mode)
694 return 0;
Damien Miller49d795c2002-01-22 23:34:12 +1100695 for (msg = prompt;;msg = again) {
696 p = read_passphrase(msg, RP_ECHO);
697 if (p == NULL ||
698 (p[0] == '\0') || (p[0] == '\n') ||
699 strncasecmp(p, "no", 2) == 0)
700 ret = 0;
Ben Lindstrom04f9af72002-07-04 00:03:56 +0000701 if (p && strncasecmp(p, "yes", 3) == 0)
Damien Miller49d795c2002-01-22 23:34:12 +1100702 ret = 1;
Darren Tuckera627d422013-06-02 07:31:17 +1000703 free(p);
Damien Miller49d795c2002-01-22 23:34:12 +1100704 if (ret != -1)
705 return ret;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000706 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000707}
708
Damien Miller0a80ca12010-02-27 07:55:05 +1100709static int
710check_host_cert(const char *host, const Key *host_key)
711{
712 const char *reason;
713
714 if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
715 error("%s", reason);
716 return 0;
717 }
Damien Miller86687062014-07-02 15:28:02 +1000718 if (buffer_len(host_key->cert->critical) != 0) {
Damien Miller4e270b02010-04-16 15:56:21 +1000719 error("Certificate for %s contains unsupported "
720 "critical options(s)", host);
Damien Miller0a80ca12010-02-27 07:55:05 +1100721 return 0;
722 }
723 return 1;
724}
725
Damien Millerd925dcd2010-12-01 12:21:51 +1100726static int
727sockaddr_is_local(struct sockaddr *hostaddr)
728{
729 switch (hostaddr->sa_family) {
730 case AF_INET:
731 return (ntohl(((struct sockaddr_in *)hostaddr)->
732 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
733 case AF_INET6:
734 return IN6_IS_ADDR_LOOPBACK(
735 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
736 default:
737 return 0;
738 }
739}
740
741/*
742 * Prepare the hostname and ip address strings that are used to lookup
743 * host keys in known_hosts files. These may have a port number appended.
744 */
745void
746get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
747 u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
748{
749 char ntop[NI_MAXHOST];
750 socklen_t addrlen;
751
752 switch (hostaddr == NULL ? -1 : hostaddr->sa_family) {
753 case -1:
754 addrlen = 0;
755 break;
756 case AF_INET:
757 addrlen = sizeof(struct sockaddr_in);
758 break;
759 case AF_INET6:
760 addrlen = sizeof(struct sockaddr_in6);
761 break;
762 default:
763 addrlen = sizeof(struct sockaddr);
764 break;
765 }
766
767 /*
768 * We don't have the remote ip-address for connections
769 * using a proxy command
770 */
771 if (hostfile_ipaddr != NULL) {
772 if (options.proxy_command == NULL) {
773 if (getnameinfo(hostaddr, addrlen,
774 ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
djm@openbsd.org9ce86c92015-01-28 22:36:00 +0000775 fatal("%s: getnameinfo failed", __func__);
Damien Millerd925dcd2010-12-01 12:21:51 +1100776 *hostfile_ipaddr = put_host_port(ntop, port);
777 } else {
778 *hostfile_ipaddr = xstrdup("<no hostip for proxy "
779 "command>");
780 }
781 }
782
783 /*
784 * Allow the user to record the key under a different name or
785 * differentiate a non-standard port. This is useful for ssh
786 * tunneling over forwarded connections or if you run multiple
787 * sshd's on different ports on the same machine.
788 */
789 if (hostfile_hostname != NULL) {
790 if (options.host_key_alias != NULL) {
791 *hostfile_hostname = xstrdup(options.host_key_alias);
792 debug("using hostkeyalias: %s", *hostfile_hostname);
793 } else {
794 *hostfile_hostname = put_host_port(hostname, port);
795 }
796 }
797}
798
Damien Miller95def091999-11-25 00:26:21 +1100799/*
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000800 * check whether the supplied host key is valid, return -1 if the key
Damien Miller295ee632011-05-29 21:42:31 +1000801 * is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
Damien Miller95def091999-11-25 00:26:21 +1100802 */
Damien Millerda828392006-08-05 11:35:45 +1000803#define RDRW 0
804#define RDONLY 1
805#define ROQUIET 2
Ben Lindstrombba81212001-06-25 05:01:22 +0000806static int
Damien Millerda828392006-08-05 11:35:45 +1000807check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
Damien Miller295ee632011-05-29 21:42:31 +1000808 Key *host_key, int readonly,
809 char **user_hostfiles, u_int num_user_hostfiles,
810 char **system_hostfiles, u_int num_system_hostfiles)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000811{
Damien Miller95def091999-11-25 00:26:21 +1100812 HostStatus host_status;
813 HostStatus ip_status;
Damien Miller295ee632011-05-29 21:42:31 +1000814 Key *raw_key = NULL;
815 char *ip = NULL, *host = NULL;
816 char hostline[1000], *hostp, *fp, *ra;
Damien Miller49d795c2002-01-22 23:34:12 +1100817 char msg[1024];
Damien Miller295ee632011-05-29 21:42:31 +1000818 const char *type;
Damien Millerd925dcd2010-12-01 12:21:51 +1100819 const struct hostkey_entry *host_found, *ip_found;
Damien Miller295ee632011-05-29 21:42:31 +1000820 int len, cancelled_forwarding = 0;
821 int local = sockaddr_is_local(hostaddr);
822 int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
djm@openbsd.org8d4f8722015-01-26 03:04:45 +0000823 int hostkey_trusted = 0; /* Known or explicitly accepted by user */
Damien Miller295ee632011-05-29 21:42:31 +1000824 struct hostkeys *host_hostkeys, *ip_hostkeys;
825 u_int i;
Damien Miller34132e52000-01-14 15:45:46 +1100826
827 /*
828 * Force accepting of the host key for loopback/localhost. The
829 * problem is that if the home directory is NFS-mounted to multiple
830 * machines, localhost will refer to a different machine in each of
831 * them, and the user will get bogus HOST_CHANGED warnings. This
832 * essentially disables host authentication for localhost; however,
833 * this is probably not a real problem.
834 */
Ben Lindstrom3cecc9a2001-10-03 17:39:38 +0000835 if (options.no_host_authentication_for_localhost == 1 && local &&
836 options.host_key_alias == NULL) {
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000837 debug("Forcing accepting of host key for "
838 "loopback/localhost.");
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000839 return 0;
Damien Miller34132e52000-01-14 15:45:46 +1100840 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000841
Damien Milleraae6c611999-12-06 11:47:28 +1100842 /*
Damien Millerd925dcd2010-12-01 12:21:51 +1100843 * Prepare the hostname and address strings used for hostkey lookup.
844 * In some cases, these will have a port number appended.
Damien Milleraae6c611999-12-06 11:47:28 +1100845 */
Damien Millerd925dcd2010-12-01 12:21:51 +1100846 get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
Darren Tucker78913e02008-06-13 04:47:34 +1000847
848 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000849 * Turn off check_host_ip if the connection is to localhost, via proxy
850 * command or if we don't have a hostname to compare with
851 */
Darren Tuckerda345532006-07-10 23:04:19 +1000852 if (options.check_host_ip && (local ||
853 strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
Damien Milleraae6c611999-12-06 11:47:28 +1100854 options.check_host_ip = 0;
855
Damien Millerd925dcd2010-12-01 12:21:51 +1100856 host_hostkeys = init_hostkeys();
Damien Miller295ee632011-05-29 21:42:31 +1000857 for (i = 0; i < num_user_hostfiles; i++)
858 load_hostkeys(host_hostkeys, host, user_hostfiles[i]);
859 for (i = 0; i < num_system_hostfiles; i++)
860 load_hostkeys(host_hostkeys, host, system_hostfiles[i]);
Damien Millerd925dcd2010-12-01 12:21:51 +1100861
862 ip_hostkeys = NULL;
863 if (!want_cert && options.check_host_ip) {
864 ip_hostkeys = init_hostkeys();
Damien Miller295ee632011-05-29 21:42:31 +1000865 for (i = 0; i < num_user_hostfiles; i++)
866 load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]);
867 for (i = 0; i < num_system_hostfiles; i++)
868 load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000869 }
870
Damien Miller0a80ca12010-02-27 07:55:05 +1100871 retry:
Damien Millerd925dcd2010-12-01 12:21:51 +1100872 /* Reload these as they may have changed on cert->key downgrade */
Damien Miller0a80ca12010-02-27 07:55:05 +1100873 want_cert = key_is_cert(host_key);
874 type = key_type(host_key);
875
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000876 /*
Damien Miller788f2122005-11-05 15:14:59 +1100877 * Check if the host key is present in the user's list of known
Damien Miller5428f641999-11-25 11:54:57 +1100878 * hosts or in the systemwide list.
879 */
Damien Millerd925dcd2010-12-01 12:21:51 +1100880 host_status = check_key_in_hostkeys(host_hostkeys, host_key,
881 &host_found);
882
Damien Miller5428f641999-11-25 11:54:57 +1100883 /*
Damien Miller5428f641999-11-25 11:54:57 +1100884 * Also perform check for the ip address, skip the check if we are
Damien Miller0a80ca12010-02-27 07:55:05 +1100885 * localhost, looking for a certificate, or the hostname was an ip
886 * address to begin with.
Damien Miller5428f641999-11-25 11:54:57 +1100887 */
Damien Millerd925dcd2010-12-01 12:21:51 +1100888 if (!want_cert && ip_hostkeys != NULL) {
889 ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
890 &ip_found);
Damien Miller95def091999-11-25 00:26:21 +1100891 if (host_status == HOST_CHANGED &&
Damien Millerd925dcd2010-12-01 12:21:51 +1100892 (ip_status != HOST_CHANGED ||
893 (ip_found != NULL &&
894 !key_equal(ip_found->key, host_found->key))))
Damien Miller95def091999-11-25 00:26:21 +1100895 host_ip_differ = 1;
Damien Miller95def091999-11-25 00:26:21 +1100896 } else
897 ip_status = host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000898
Damien Miller95def091999-11-25 00:26:21 +1100899 switch (host_status) {
900 case HOST_OK:
901 /* The host is known and the key matches. */
Damien Miller0a80ca12010-02-27 07:55:05 +1100902 debug("Host '%.200s' is known and matches the %s host %s.",
903 host, type, want_cert ? "certificate" : "key");
Damien Millerd925dcd2010-12-01 12:21:51 +1100904 debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
905 host_found->file, host_found->line);
Damien Miller0a80ca12010-02-27 07:55:05 +1100906 if (want_cert && !check_host_cert(hostname, host_key))
907 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000908 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Miller0a80ca12010-02-27 07:55:05 +1100909 if (readonly || want_cert)
Damien Miller996acd22003-04-09 20:59:48 +1000910 logit("%s host key for IP address "
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000911 "'%.128s' not in list of known hosts.",
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000912 type, ip);
Damien Miller295ee632011-05-29 21:42:31 +1000913 else if (!add_host_to_hostfile(user_hostfiles[0], ip,
Damien Millere1776152005-03-01 21:47:37 +1100914 host_key, options.hash_known_hosts))
Damien Miller996acd22003-04-09 20:59:48 +1000915 logit("Failed to add the %s host key for IP "
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000916 "address '%.128s' to the list of known "
dtucker@openbsd.org496aeb22015-05-28 05:41:29 +0000917 "hosts (%.500s).", type, ip,
Damien Miller295ee632011-05-29 21:42:31 +1000918 user_hostfiles[0]);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000919 else
Damien Miller996acd22003-04-09 20:59:48 +1000920 logit("Warning: Permanently added the %s host "
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000921 "key for IP address '%.128s' to the list "
922 "of known hosts.", type, ip);
Damien Miller10288242008-06-30 00:04:03 +1000923 } else if (options.visual_host_key) {
djm@openbsd.org9ce86c92015-01-28 22:36:00 +0000924 fp = sshkey_fingerprint(host_key,
djm@openbsd.org56d1c832014-12-21 22:27:55 +0000925 options.fingerprint_hash, SSH_FP_DEFAULT);
djm@openbsd.org9ce86c92015-01-28 22:36:00 +0000926 ra = sshkey_fingerprint(host_key,
djm@openbsd.org56d1c832014-12-21 22:27:55 +0000927 options.fingerprint_hash, SSH_FP_RANDOMART);
djm@openbsd.org9ce86c92015-01-28 22:36:00 +0000928 if (fp == NULL || ra == NULL)
929 fatal("%s: sshkey_fingerprint fail", __func__);
djm@openbsd.orgac3451d2015-09-04 03:57:38 +0000930 logit("Host key fingerprint is %s\n%s", fp, ra);
Darren Tuckera627d422013-06-02 07:31:17 +1000931 free(ra);
932 free(fp);
Damien Miller95def091999-11-25 00:26:21 +1100933 }
djm@openbsd.org8d4f8722015-01-26 03:04:45 +0000934 hostkey_trusted = 1;
Damien Miller95def091999-11-25 00:26:21 +1100935 break;
936 case HOST_NEW:
Damien Millerda828392006-08-05 11:35:45 +1000937 if (options.host_key_alias == NULL && port != 0 &&
938 port != SSH_DEFAULT_PORT) {
939 debug("checking without port identifier");
Damien Millerece92c82008-11-03 19:25:03 +1100940 if (check_host_key(hostname, hostaddr, 0, host_key,
Damien Miller295ee632011-05-29 21:42:31 +1000941 ROQUIET, user_hostfiles, num_user_hostfiles,
942 system_hostfiles, num_system_hostfiles) == 0) {
Damien Millerda828392006-08-05 11:35:45 +1000943 debug("found matching key w/out port");
944 break;
945 }
946 }
Damien Miller0a80ca12010-02-27 07:55:05 +1100947 if (readonly || want_cert)
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000948 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100949 /* The host is new. */
950 if (options.strict_host_key_checking == 1) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000951 /*
952 * User has requested strict host key checking. We
953 * will not add the host key automatically. The only
954 * alternative left is to abort.
955 */
956 error("No %s host key is known for %.200s and you "
957 "have requested strict checking.", type, host);
958 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100959 } else if (options.strict_host_key_checking == 2) {
Damien Miller7392ae62003-06-11 22:05:25 +1000960 char msg1[1024], msg2[1024];
961
Damien Millerd925dcd2010-12-01 12:21:51 +1100962 if (show_other_keys(host_hostkeys, host_key))
Damien Miller7392ae62003-06-11 22:05:25 +1000963 snprintf(msg1, sizeof(msg1),
Damien Miller0dc1bef2005-07-17 17:22:45 +1000964 "\nbut keys of different type are already"
965 " known for this host.");
Damien Miller7392ae62003-06-11 22:05:25 +1000966 else
967 snprintf(msg1, sizeof(msg1), ".");
Damien Miller95def091999-11-25 00:26:21 +1100968 /* The default */
djm@openbsd.org9ce86c92015-01-28 22:36:00 +0000969 fp = sshkey_fingerprint(host_key,
djm@openbsd.org56d1c832014-12-21 22:27:55 +0000970 options.fingerprint_hash, SSH_FP_DEFAULT);
djm@openbsd.org9ce86c92015-01-28 22:36:00 +0000971 ra = sshkey_fingerprint(host_key,
djm@openbsd.org56d1c832014-12-21 22:27:55 +0000972 options.fingerprint_hash, SSH_FP_RANDOMART);
djm@openbsd.org9ce86c92015-01-28 22:36:00 +0000973 if (fp == NULL || ra == NULL)
974 fatal("%s: sshkey_fingerprint fail", __func__);
Damien Miller7392ae62003-06-11 22:05:25 +1000975 msg2[0] = '\0';
Damien Miller7392ae62003-06-11 22:05:25 +1000976 if (options.verify_host_key_dns) {
Damien Miller150b5572003-11-17 21:19:29 +1100977 if (matching_host_key_dns)
Damien Miller7392ae62003-06-11 22:05:25 +1000978 snprintf(msg2, sizeof(msg2),
979 "Matching host key fingerprint"
980 " found in DNS.\n");
981 else
982 snprintf(msg2, sizeof(msg2),
983 "No matching host key fingerprint"
984 " found in DNS.\n");
985 }
Damien Miller49d795c2002-01-22 23:34:12 +1100986 snprintf(msg, sizeof(msg),
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000987 "The authenticity of host '%.200s (%s)' can't be "
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000988 "established%s\n"
Damien Miller10288242008-06-30 00:04:03 +1000989 "%s key fingerprint is %s.%s%s\n%s"
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000990 "Are you sure you want to continue connecting "
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000991 "(yes/no)? ",
Damien Miller10288242008-06-30 00:04:03 +1000992 host, ip, msg1, type, fp,
993 options.visual_host_key ? "\n" : "",
994 options.visual_host_key ? ra : "",
995 msg2);
Darren Tuckera627d422013-06-02 07:31:17 +1000996 free(ra);
997 free(fp);
Damien Miller49d795c2002-01-22 23:34:12 +1100998 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000999 goto fail;
djm@openbsd.org8d4f8722015-01-26 03:04:45 +00001000 hostkey_trusted = 1; /* user explicitly confirmed */
Damien Miller95def091999-11-25 00:26:21 +11001001 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001002 /*
1003 * If not in strict mode, add the key automatically to the
1004 * local known_hosts file.
1005 */
Damien Miller1227d4c2005-03-02 12:06:51 +11001006 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Millerd925dcd2010-12-01 12:21:51 +11001007 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
Damien Miller1227d4c2005-03-02 12:06:51 +11001008 hostp = hostline;
1009 if (options.hash_known_hosts) {
1010 /* Add hash of host and IP separately */
Damien Miller295ee632011-05-29 21:42:31 +10001011 r = add_host_to_hostfile(user_hostfiles[0],
1012 host, host_key, options.hash_known_hosts) &&
1013 add_host_to_hostfile(user_hostfiles[0], ip,
Damien Miller1227d4c2005-03-02 12:06:51 +11001014 host_key, options.hash_known_hosts);
1015 } else {
1016 /* Add unhashed "host,ip" */
Damien Miller295ee632011-05-29 21:42:31 +10001017 r = add_host_to_hostfile(user_hostfiles[0],
Damien Miller1227d4c2005-03-02 12:06:51 +11001018 hostline, host_key,
1019 options.hash_known_hosts);
1020 }
1021 } else {
Damien Miller295ee632011-05-29 21:42:31 +10001022 r = add_host_to_hostfile(user_hostfiles[0], host,
1023 host_key, options.hash_known_hosts);
Damien Miller1227d4c2005-03-02 12:06:51 +11001024 hostp = host;
1025 }
1026
1027 if (!r)
Damien Miller996acd22003-04-09 20:59:48 +10001028 logit("Failed to add the host to the list of known "
Damien Miller295ee632011-05-29 21:42:31 +10001029 "hosts (%.500s).", user_hostfiles[0]);
Damien Miller95def091999-11-25 00:26:21 +11001030 else
Damien Miller996acd22003-04-09 20:59:48 +10001031 logit("Warning: Permanently added '%.200s' (%s) to the "
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001032 "list of known hosts.", hostp, type);
Damien Miller95def091999-11-25 00:26:21 +11001033 break;
Damien Miller1aed65e2010-03-04 21:53:35 +11001034 case HOST_REVOKED:
1035 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1036 error("@ WARNING: REVOKED HOST KEY DETECTED! @");
1037 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1038 error("The %s host key for %s is marked as revoked.", type, host);
1039 error("This could mean that a stolen key is being used to");
1040 error("impersonate this host.");
1041
1042 /*
1043 * If strict host key checking is in use, the user will have
1044 * to edit the key manually and we can only abort.
1045 */
1046 if (options.strict_host_key_checking) {
1047 error("%s host key for %.200s was revoked and you have "
1048 "requested strict checking.", type, host);
1049 goto fail;
1050 }
1051 goto continue_unsafe;
1052
Damien Miller95def091999-11-25 00:26:21 +11001053 case HOST_CHANGED:
Damien Miller0a80ca12010-02-27 07:55:05 +11001054 if (want_cert) {
1055 /*
1056 * This is only a debug() since it is valid to have
1057 * CAs with wildcard DNS matches that don't match
1058 * all hosts that one might visit.
1059 */
1060 debug("Host certificate authority does not "
Damien Millerd925dcd2010-12-01 12:21:51 +11001061 "match %s in %s:%lu", CA_MARKER,
1062 host_found->file, host_found->line);
Damien Miller0a80ca12010-02-27 07:55:05 +11001063 goto fail;
1064 }
Damien Millerda828392006-08-05 11:35:45 +10001065 if (readonly == ROQUIET)
1066 goto fail;
Damien Miller95def091999-11-25 00:26:21 +11001067 if (options.check_host_ip && host_ip_differ) {
Darren Tucker3f9fdc72004-06-22 12:56:01 +10001068 char *key_msg;
Damien Miller95def091999-11-25 00:26:21 +11001069 if (ip_status == HOST_NEW)
Darren Tucker3f9fdc72004-06-22 12:56:01 +10001070 key_msg = "is unknown";
Damien Miller95def091999-11-25 00:26:21 +11001071 else if (ip_status == HOST_OK)
Darren Tucker3f9fdc72004-06-22 12:56:01 +10001072 key_msg = "is unchanged";
Damien Miller95def091999-11-25 00:26:21 +11001073 else
Darren Tucker3f9fdc72004-06-22 12:56:01 +10001074 key_msg = "has a different value";
Damien Miller95def091999-11-25 00:26:21 +11001075 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1076 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
1077 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millere247cc42000-05-07 12:03:14 +10001078 error("The %s host key for %s has changed,", type, host);
Darren Tuckerff4454d2008-06-13 10:21:51 +10001079 error("and the key for the corresponding IP address %s", ip);
Darren Tucker3f9fdc72004-06-22 12:56:01 +10001080 error("%s. This could either mean that", key_msg);
Damien Miller95def091999-11-25 00:26:21 +11001081 error("DNS SPOOFING is happening or the IP address for the host");
Ben Lindstrom46c16222000-12-22 01:43:59 +00001082 error("and its host key have changed at the same time.");
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001083 if (ip_status != HOST_NEW)
Damien Millerd925dcd2010-12-01 12:21:51 +11001084 error("Offending key for IP in %s:%lu",
1085 ip_found->file, ip_found->line);
Damien Miller95def091999-11-25 00:26:21 +11001086 }
1087 /* The host key has changed. */
Damien Miller5a388972003-11-17 21:10:47 +11001088 warn_changed_key(host_key);
Damien Miller95def091999-11-25 00:26:21 +11001089 error("Add correct host key in %.100s to get rid of this message.",
Damien Miller295ee632011-05-29 21:42:31 +10001090 user_hostfiles[0]);
Damien Millerd925dcd2010-12-01 12:21:51 +11001091 error("Offending %s key in %s:%lu", key_type(host_found->key),
1092 host_found->file, host_found->line);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001093
Damien Miller5428f641999-11-25 11:54:57 +11001094 /*
1095 * If strict host key checking is in use, the user will have
1096 * to edit the key manually and we can only abort.
1097 */
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001098 if (options.strict_host_key_checking) {
1099 error("%s host key for %.200s has changed and you have "
1100 "requested strict checking.", type, host);
1101 goto fail;
1102 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001103
Damien Miller1aed65e2010-03-04 21:53:35 +11001104 continue_unsafe:
Damien Miller5428f641999-11-25 11:54:57 +11001105 /*
1106 * If strict host key checking has not been requested, allow
Damien Miller941ac452003-06-04 20:31:53 +10001107 * the connection but without MITM-able authentication or
Damien Miller437edb92006-08-05 09:11:13 +10001108 * forwarding.
Damien Miller5428f641999-11-25 11:54:57 +11001109 */
Damien Miller95def091999-11-25 00:26:21 +11001110 if (options.password_authentication) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001111 error("Password authentication is disabled to avoid "
1112 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +11001113 options.password_authentication = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001114 cancelled_forwarding = 1;
Damien Miller95def091999-11-25 00:26:21 +11001115 }
Damien Miller941ac452003-06-04 20:31:53 +10001116 if (options.kbd_interactive_authentication) {
1117 error("Keyboard-interactive authentication is disabled"
1118 " to avoid man-in-the-middle attacks.");
1119 options.kbd_interactive_authentication = 0;
1120 options.challenge_response_authentication = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001121 cancelled_forwarding = 1;
Damien Miller941ac452003-06-04 20:31:53 +10001122 }
1123 if (options.challenge_response_authentication) {
1124 error("Challenge/response authentication is disabled"
1125 " to avoid man-in-the-middle attacks.");
1126 options.challenge_response_authentication = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001127 cancelled_forwarding = 1;
Damien Miller941ac452003-06-04 20:31:53 +10001128 }
Damien Miller95def091999-11-25 00:26:21 +11001129 if (options.forward_agent) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001130 error("Agent forwarding is disabled to avoid "
1131 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +11001132 options.forward_agent = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001133 cancelled_forwarding = 1;
Damien Miller95def091999-11-25 00:26:21 +11001134 }
Ben Lindstromc72745a2000-12-02 19:03:54 +00001135 if (options.forward_x11) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001136 error("X11 forwarding is disabled to avoid "
1137 "man-in-the-middle attacks.");
Ben Lindstromc72745a2000-12-02 19:03:54 +00001138 options.forward_x11 = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001139 cancelled_forwarding = 1;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001140 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001141 if (options.num_local_forwards > 0 ||
1142 options.num_remote_forwards > 0) {
1143 error("Port forwarding is disabled to avoid "
1144 "man-in-the-middle attacks.");
1145 options.num_local_forwards =
Damien Miller9f0f5c62001-12-21 14:45:46 +11001146 options.num_remote_forwards = 0;
Darren Tucker068e01f2008-07-02 22:33:55 +10001147 cancelled_forwarding = 1;
Ben Lindstromc72745a2000-12-02 19:03:54 +00001148 }
Damien Miller437edb92006-08-05 09:11:13 +10001149 if (options.tun_open != SSH_TUNMODE_NO) {
1150 error("Tunnel forwarding is disabled to avoid "
1151 "man-in-the-middle attacks.");
1152 options.tun_open = SSH_TUNMODE_NO;
Darren Tucker068e01f2008-07-02 22:33:55 +10001153 cancelled_forwarding = 1;
Damien Miller437edb92006-08-05 09:11:13 +10001154 }
Darren Tucker068e01f2008-07-02 22:33:55 +10001155 if (options.exit_on_forward_failure && cancelled_forwarding)
1156 fatal("Error: forwarding disabled due to host key "
1157 "check failure");
1158
Damien Miller5428f641999-11-25 11:54:57 +11001159 /*
1160 * XXX Should permit the user to change to use the new id.
1161 * This could be done by converting the host key to an
1162 * identifying sentence, tell that the host identifies itself
Darren Tuckere2b36742010-01-13 22:42:34 +11001163 * by that sentence, and ask the user if he/she wishes to
Damien Miller5428f641999-11-25 11:54:57 +11001164 * accept the authentication.
1165 */
Damien Miller95def091999-11-25 00:26:21 +11001166 break;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001167 case HOST_FOUND:
1168 fatal("internal error");
1169 break;
Damien Miller95def091999-11-25 00:26:21 +11001170 }
Ben Lindstromc72745a2000-12-02 19:03:54 +00001171
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001172 if (options.check_host_ip && host_status != HOST_CHANGED &&
1173 ip_status == HOST_CHANGED) {
Damien Miller49d795c2002-01-22 23:34:12 +11001174 snprintf(msg, sizeof(msg),
1175 "Warning: the %s host key for '%.200s' "
1176 "differs from the key for the IP address '%.128s'"
Damien Millerd925dcd2010-12-01 12:21:51 +11001177 "\nOffending key for IP in %s:%lu",
1178 type, host, ip, ip_found->file, ip_found->line);
Damien Miller49d795c2002-01-22 23:34:12 +11001179 if (host_status == HOST_OK) {
1180 len = strlen(msg);
1181 snprintf(msg + len, sizeof(msg) - len,
Damien Millerd925dcd2010-12-01 12:21:51 +11001182 "\nMatching host key in %s:%lu",
1183 host_found->file, host_found->line);
Damien Miller49d795c2002-01-22 23:34:12 +11001184 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001185 if (options.strict_host_key_checking == 1) {
Damien Millerab2db412003-06-02 19:09:13 +10001186 logit("%s", msg);
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001187 error("Exiting, you have requested strict checking.");
1188 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001189 } else if (options.strict_host_key_checking == 2) {
Damien Miller49d795c2002-01-22 23:34:12 +11001190 strlcat(msg, "\nAre you sure you want "
1191 "to continue connecting (yes/no)? ", sizeof(msg));
1192 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001193 goto fail;
Damien Miller49d795c2002-01-22 23:34:12 +11001194 } else {
Damien Millerab2db412003-06-02 19:09:13 +10001195 logit("%s", msg);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +00001196 }
1197 }
1198
djm@openbsd.org8d4f8722015-01-26 03:04:45 +00001199 if (!hostkey_trusted && options.update_hostkeys) {
1200 debug("%s: hostkey not known or explicitly trusted: "
1201 "disabling UpdateHostkeys", __func__);
1202 options.update_hostkeys = 0;
1203 }
1204
Darren Tuckera627d422013-06-02 07:31:17 +10001205 free(ip);
1206 free(host);
Damien Millerd925dcd2010-12-01 12:21:51 +11001207 if (host_hostkeys != NULL)
1208 free_hostkeys(host_hostkeys);
1209 if (ip_hostkeys != NULL)
1210 free_hostkeys(ip_hostkeys);
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001211 return 0;
1212
1213fail:
Damien Miller1aed65e2010-03-04 21:53:35 +11001214 if (want_cert && host_status != HOST_REVOKED) {
Damien Miller0a80ca12010-02-27 07:55:05 +11001215 /*
1216 * No matching certificate. Downgrade cert to raw key and
1217 * search normally.
1218 */
1219 debug("No matching CA found. Retry with plain key");
1220 raw_key = key_from_private(host_key);
1221 if (key_drop_cert(raw_key) != 0)
1222 fatal("Couldn't drop certificate");
1223 host_key = raw_key;
1224 goto retry;
1225 }
1226 if (raw_key != NULL)
1227 key_free(raw_key);
Darren Tuckera627d422013-06-02 07:31:17 +10001228 free(ip);
1229 free(host);
Damien Millerd925dcd2010-12-01 12:21:51 +11001230 if (host_hostkeys != NULL)
1231 free_hostkeys(host_hostkeys);
1232 if (ip_hostkeys != NULL)
1233 free_hostkeys(ip_hostkeys);
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001234 return -1;
1235}
1236
Damien Miller37876e92003-05-15 10:19:46 +10001237/* returns 0 if key verifies or -1 if key does NOT verify */
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001238int
1239verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
1240{
djm@openbsd.orgf96516d2015-11-19 01:09:38 +00001241 u_int i;
Damien Miller6b37fbb2014-07-04 08:59:24 +10001242 int r = -1, flags = 0;
djm@openbsd.orgf96516d2015-11-19 01:09:38 +00001243 char valid[64], *fp = NULL, *cafp = NULL;
djm@openbsd.org5e39a492014-12-04 02:24:32 +00001244 struct sshkey *plain = NULL;
Damien Millerd925dcd2010-12-01 12:21:51 +11001245
djm@openbsd.org5e39a492014-12-04 02:24:32 +00001246 if ((fp = sshkey_fingerprint(host_key,
djm@openbsd.org56d1c832014-12-21 22:27:55 +00001247 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
djm@openbsd.org5e39a492014-12-04 02:24:32 +00001248 error("%s: fingerprint host key: %s", __func__, ssh_err(r));
1249 r = -1;
1250 goto out;
1251 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +00001252
djm@openbsd.orgf96516d2015-11-19 01:09:38 +00001253 if (sshkey_is_cert(host_key)) {
1254 if ((cafp = sshkey_fingerprint(host_key->cert->signature_key,
1255 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) {
1256 error("%s: fingerprint CA key: %s",
1257 __func__, ssh_err(r));
1258 r = -1;
1259 goto out;
1260 }
1261 sshkey_format_cert_validity(host_key->cert,
1262 valid, sizeof(valid));
1263 debug("Server host certificate: %s %s, serial %llu "
1264 "ID \"%s\" CA %s %s valid %s",
1265 sshkey_ssh_name(host_key), fp,
djm@openbsd.org8ca915f2015-11-20 01:45:29 +00001266 (unsigned long long)host_key->cert->serial,
1267 host_key->cert->key_id,
djm@openbsd.orgf96516d2015-11-19 01:09:38 +00001268 sshkey_ssh_name(host_key->cert->signature_key), cafp,
1269 valid);
1270 for (i = 0; i < host_key->cert->nprincipals; i++) {
1271 debug2("Server host certificate hostname: %s",
1272 host_key->cert->principals[i]);
1273 }
1274 } else {
1275 debug("Server host key: %s %s", compat20 ?
1276 sshkey_ssh_name(host_key) : sshkey_type(host_key), fp);
1277 }
djm@openbsd.org5e39a492014-12-04 02:24:32 +00001278
1279 if (sshkey_equal(previous_host_key, host_key)) {
1280 debug2("%s: server host key %s %s matches cached key",
1281 __func__, sshkey_type(host_key), fp);
1282 r = 0;
1283 goto out;
1284 }
1285
1286 /* Check in RevokedHostKeys file if specified */
1287 if (options.revoked_host_keys != NULL) {
1288 r = sshkey_check_revoked(host_key, options.revoked_host_keys);
1289 switch (r) {
1290 case 0:
1291 break; /* not revoked */
1292 case SSH_ERR_KEY_REVOKED:
1293 error("Host key %s %s revoked by file %s",
1294 sshkey_type(host_key), fp,
1295 options.revoked_host_keys);
1296 r = -1;
1297 goto out;
1298 default:
1299 error("Error checking host key %s %s in "
1300 "revoked keys file %s: %s", sshkey_type(host_key),
1301 fp, options.revoked_host_keys, ssh_err(r));
1302 r = -1;
1303 goto out;
1304 }
Damien Miller6b37fbb2014-07-04 08:59:24 +10001305 }
1306
Damien Miller7d6a9fb2014-04-20 13:23:43 +10001307 if (options.verify_host_key_dns) {
1308 /*
1309 * XXX certs are not yet supported for DNS, so downgrade
1310 * them and try the plain key.
1311 */
djm@openbsd.org5e39a492014-12-04 02:24:32 +00001312 if ((r = sshkey_from_private(host_key, &plain)) != 0)
1313 goto out;
1314 if (sshkey_is_cert(plain))
1315 sshkey_drop_cert(plain);
Damien Miller7d6a9fb2014-04-20 13:23:43 +10001316 if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) {
1317 if (flags & DNS_VERIFY_FOUND) {
1318 if (options.verify_host_key_dns == 1 &&
1319 flags & DNS_VERIFY_MATCH &&
1320 flags & DNS_VERIFY_SECURE) {
Damien Miller6b37fbb2014-07-04 08:59:24 +10001321 r = 0;
djm@openbsd.org5e39a492014-12-04 02:24:32 +00001322 goto out;
Damien Miller7d6a9fb2014-04-20 13:23:43 +10001323 }
1324 if (flags & DNS_VERIFY_MATCH) {
1325 matching_host_key_dns = 1;
1326 } else {
1327 warn_changed_key(plain);
1328 error("Update the SSHFP RR in DNS "
1329 "with the new host key to get rid "
1330 "of this message.");
1331 }
Damien Miller150b5572003-11-17 21:19:29 +11001332 }
Damien Miller37876e92003-05-15 10:19:46 +10001333 }
1334 }
Damien Miller6b37fbb2014-07-04 08:59:24 +10001335 r = check_host_key(host, hostaddr, options.port, host_key, RDRW,
Damien Miller295ee632011-05-29 21:42:31 +10001336 options.user_hostfiles, options.num_user_hostfiles,
1337 options.system_hostfiles, options.num_system_hostfiles);
Damien Miller6b37fbb2014-07-04 08:59:24 +10001338
djm@openbsd.org5e39a492014-12-04 02:24:32 +00001339out:
1340 sshkey_free(plain);
1341 free(fp);
djm@openbsd.orgf96516d2015-11-19 01:09:38 +00001342 free(cafp);
Damien Miller6b37fbb2014-07-04 08:59:24 +10001343 if (r == 0 && host_key != NULL) {
1344 key_free(previous_host_key);
1345 previous_host_key = key_from_private(host_key);
1346 }
1347
1348 return r;
Damien Millera34a28b1999-12-14 10:47:15 +11001349}
Damien Miller037a0dc1999-12-07 15:38:31 +11001350
Damien Miller396691a2000-01-20 22:44:08 +11001351/*
1352 * Starts a dialog with the server, and authenticates the current user on the
1353 * server. This does not need any extra privileges. The basic connection
1354 * to the server must already have been established before this is called.
1355 * If login fails, this function prints an error and never returns.
1356 * This function does not require super-user privileges.
1357 */
1358void
Ben Lindstrom1bad2562002-06-06 19:57:33 +00001359ssh_login(Sensitive *sensitive, const char *orighost,
Damien Millerd925dcd2010-12-01 12:21:51 +11001360 struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
Damien Miller396691a2000-01-20 22:44:08 +11001361{
Damien Miller0faf7472013-10-17 11:47:23 +11001362 char *host;
Damien Millereba71ba2000-04-29 23:57:08 +10001363 char *server_user, *local_user;
1364
Damien Millereba71ba2000-04-29 23:57:08 +10001365 local_user = xstrdup(pw->pw_name);
1366 server_user = options.user ? options.user : local_user;
Damien Miller396691a2000-01-20 22:44:08 +11001367
1368 /* Convert the user-supplied hostname into all lowercase. */
1369 host = xstrdup(orighost);
Damien Miller0faf7472013-10-17 11:47:23 +11001370 lowercase(host);
Damien Miller396691a2000-01-20 22:44:08 +11001371
1372 /* Exchange protocol version identification strings with the server. */
Damien Miller67bd0622007-09-17 12:06:57 +10001373 ssh_exchange_identification(timeout_ms);
Damien Miller396691a2000-01-20 22:44:08 +11001374
1375 /* Put the connection into non-blocking mode. */
1376 packet_set_nonblocking();
1377
Damien Miller396691a2000-01-20 22:44:08 +11001378 /* key exchange */
Damien Miller396691a2000-01-20 22:44:08 +11001379 /* authenticate user */
dtucker@openbsd.orgbb2289e2015-04-14 04:17:03 +00001380 debug("Authenticating to %s:%d as '%s'", host, port, server_user);
Damien Miller1383bd82000-04-06 12:32:37 +10001381 if (compat20) {
Damien Millerd925dcd2010-12-01 12:21:51 +11001382 ssh_kex2(host, hostaddr, port);
Ben Lindstrom1bad2562002-06-06 19:57:33 +00001383 ssh_userauth2(local_user, server_user, host, sensitive);
Damien Miller1383bd82000-04-06 12:32:37 +10001384 } else {
Damien Miller1f0311c2014-05-15 14:24:09 +10001385#ifdef WITH_SSH1
Damien Miller1383bd82000-04-06 12:32:37 +10001386 ssh_kex(host, hostaddr);
Ben Lindstrom1bad2562002-06-06 19:57:33 +00001387 ssh_userauth1(local_user, server_user, host, sensitive);
Damien Miller1f0311c2014-05-15 14:24:09 +10001388#else
djm@openbsd.org53097b22015-03-24 01:11:12 +00001389 fatal("ssh1 is not supported");
Damien Miller1f0311c2014-05-15 14:24:09 +10001390#endif
Damien Miller1383bd82000-04-06 12:32:37 +10001391 }
Darren Tuckera627d422013-06-02 07:31:17 +10001392 free(local_user);
Damien Miller396691a2000-01-20 22:44:08 +11001393}
Damien Miller79438cc2001-02-16 12:34:57 +11001394
1395void
1396ssh_put_password(char *password)
1397{
1398 int size;
1399 char *padded;
1400
Ben Lindstromd20d0f32001-03-10 17:22:20 +00001401 if (datafellows & SSH_BUG_PASSWORDPAD) {
Ben Lindstrom664408d2001-06-09 01:42:01 +00001402 packet_put_cstring(password);
Ben Lindstromd20d0f32001-03-10 17:22:20 +00001403 return;
1404 }
deraadt@openbsd.org9136ec12016-09-12 01:22:38 +00001405 size = ROUNDUP(strlen(password) + 1, 32);
Damien Miller07d86be2006-03-26 14:19:21 +11001406 padded = xcalloc(1, size);
Damien Miller79438cc2001-02-16 12:34:57 +11001407 strlcpy(padded, password, size);
1408 packet_put_string(padded, size);
Damien Millera5103f42014-02-04 11:20:14 +11001409 explicit_bzero(padded, size);
Darren Tuckera627d422013-06-02 07:31:17 +10001410 free(padded);
Damien Miller79438cc2001-02-16 12:34:57 +11001411}
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001412
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001413/* print all known host keys for a given host, but skip keys of given type */
1414static int
Damien Millerd925dcd2010-12-01 12:21:51 +11001415show_other_keys(struct hostkeys *hostkeys, Key *key)
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001416{
Damien Miller106bf1c2013-12-29 17:54:03 +11001417 int type[] = {
1418 KEY_RSA1,
1419 KEY_RSA,
1420 KEY_DSA,
1421 KEY_ECDSA,
1422 KEY_ED25519,
1423 -1
1424 };
Damien Millerd925dcd2010-12-01 12:21:51 +11001425 int i, ret = 0;
1426 char *fp, *ra;
1427 const struct hostkey_entry *found;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001428
1429 for (i = 0; type[i] != -1; i++) {
1430 if (type[i] == key->type)
1431 continue;
Damien Millerd925dcd2010-12-01 12:21:51 +11001432 if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001433 continue;
djm@openbsd.org9ce86c92015-01-28 22:36:00 +00001434 fp = sshkey_fingerprint(found->key,
djm@openbsd.org56d1c832014-12-21 22:27:55 +00001435 options.fingerprint_hash, SSH_FP_DEFAULT);
djm@openbsd.org9ce86c92015-01-28 22:36:00 +00001436 ra = sshkey_fingerprint(found->key,
djm@openbsd.org56d1c832014-12-21 22:27:55 +00001437 options.fingerprint_hash, SSH_FP_RANDOMART);
djm@openbsd.org9ce86c92015-01-28 22:36:00 +00001438 if (fp == NULL || ra == NULL)
1439 fatal("%s: sshkey_fingerprint fail", __func__);
Damien Millerd925dcd2010-12-01 12:21:51 +11001440 logit("WARNING: %s key found for host %s\n"
1441 "in %s:%lu\n"
1442 "%s key fingerprint %s.",
1443 key_type(found->key),
1444 found->host, found->file, found->line,
1445 key_type(found->key), fp);
1446 if (options.visual_host_key)
1447 logit("%s", ra);
Darren Tuckera627d422013-06-02 07:31:17 +10001448 free(ra);
1449 free(fp);
Damien Millerd925dcd2010-12-01 12:21:51 +11001450 ret = 1;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001451 }
Damien Millerd925dcd2010-12-01 12:21:51 +11001452 return ret;
Ben Lindstrom3ed66402002-08-01 01:21:56 +00001453}
Damien Miller5a388972003-11-17 21:10:47 +11001454
1455static void
1456warn_changed_key(Key *host_key)
1457{
1458 char *fp;
Damien Miller5a388972003-11-17 21:10:47 +11001459
djm@openbsd.org9ce86c92015-01-28 22:36:00 +00001460 fp = sshkey_fingerprint(host_key, options.fingerprint_hash,
djm@openbsd.org56d1c832014-12-21 22:27:55 +00001461 SSH_FP_DEFAULT);
djm@openbsd.org9ce86c92015-01-28 22:36:00 +00001462 if (fp == NULL)
1463 fatal("%s: sshkey_fingerprint fail", __func__);
Damien Miller5a388972003-11-17 21:10:47 +11001464
1465 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1466 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
1467 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
1468 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
1469 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
Damien Miller05c89972011-01-06 22:42:04 +11001470 error("It is also possible that a host key has just been changed.");
Damien Miller5a388972003-11-17 21:10:47 +11001471 error("The fingerprint for the %s key sent by the remote host is\n%s.",
Damien Miller05c89972011-01-06 22:42:04 +11001472 key_type(host_key), fp);
Damien Miller5a388972003-11-17 21:10:47 +11001473 error("Please contact your system administrator.");
1474
Darren Tuckera627d422013-06-02 07:31:17 +10001475 free(fp);
Damien Miller5a388972003-11-17 21:10:47 +11001476}
Damien Millerd27b9472005-12-13 19:29:02 +11001477
1478/*
1479 * Execute a local command
1480 */
1481int
1482ssh_local_cmd(const char *args)
1483{
1484 char *shell;
1485 pid_t pid;
1486 int status;
Damien Millered3a8eb2011-01-07 10:02:52 +11001487 void (*osighand)(int);
Damien Millerd27b9472005-12-13 19:29:02 +11001488
1489 if (!options.permit_local_command ||
1490 args == NULL || !*args)
1491 return (1);
1492
Damien Miller38d9a962010-10-07 22:07:11 +11001493 if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
Damien Millerd27b9472005-12-13 19:29:02 +11001494 shell = _PATH_BSHELL;
1495
Damien Millered3a8eb2011-01-07 10:02:52 +11001496 osighand = signal(SIGCHLD, SIG_DFL);
Damien Millerd27b9472005-12-13 19:29:02 +11001497 pid = fork();
1498 if (pid == 0) {
Damien Miller6fb6fd52011-01-16 23:17:45 +11001499 signal(SIGPIPE, SIG_DFL);
Damien Millerd27b9472005-12-13 19:29:02 +11001500 debug3("Executing %s -c \"%s\"", shell, args);
1501 execl(shell, shell, "-c", args, (char *)NULL);
1502 error("Couldn't execute %s -c \"%s\": %s",
1503 shell, args, strerror(errno));
1504 _exit(1);
1505 } else if (pid == -1)
1506 fatal("fork failed: %.100s", strerror(errno));
1507 while (waitpid(pid, &status, 0) == -1)
1508 if (errno != EINTR)
1509 fatal("Couldn't wait for child: %s", strerror(errno));
Damien Millered3a8eb2011-01-07 10:02:52 +11001510 signal(SIGCHLD, osighand);
Damien Millerd27b9472005-12-13 19:29:02 +11001511
1512 if (!WIFEXITED(status))
1513 return (1);
1514
1515 return (WEXITSTATUS(status));
1516}
jcs@openbsd.orgf361df42015-11-15 22:26:49 +00001517
1518void
1519maybe_add_key_to_agent(char *authfile, Key *private, char *comment,
1520 char *passphrase)
1521{
1522 int auth_sock = -1, r;
1523
1524 if (options.add_keys_to_agent == 0)
1525 return;
1526
1527 if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) {
1528 debug3("no authentication agent, not adding key");
1529 return;
1530 }
1531
1532 if (options.add_keys_to_agent == 2 &&
1533 !ask_permission("Add key %s (%s) to agent?", authfile, comment)) {
1534 debug3("user denied adding this key");
1535 return;
1536 }
1537
1538 if ((r = ssh_add_identity_constrained(auth_sock, private, comment, 0,
1539 (options.add_keys_to_agent == 3))) == 0)
1540 debug("identity added to agent: %s", authfile);
1541 else
1542 debug("could not add identity to agent: %s (%d)", authfile, r);
1543}