blob: b89321fb8392b9154db711ec4df28e7d058e919d [file] [log] [blame]
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11005 * Code to connect to a remote host, and to perform the client side of the
6 * login (authentication) dialog.
Damien Millere4340be2000-09-16 13:29:08 +11007 *
8 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
Damien Miller95def091999-11-25 00:26:21 +110013 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100014
15#include "includes.h"
Ben Lindstrom5c385522002-06-23 21:23:20 +000016RCSID("$OpenBSD: sshconnect.c,v 1.126 2002/06/23 03:30:17 deraadt Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100017
Damien Miller1383bd82000-04-06 12:32:37 +100018#include <openssl/bn.h>
Damien Millereba71ba2000-04-29 23:57:08 +100019
Ben Lindstrom226cfa02001-01-22 05:34:40 +000020#include "ssh.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100021#include "xmalloc.h"
22#include "rsa.h"
Damien Miller1383bd82000-04-06 12:32:37 +100023#include "buffer.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100024#include "packet.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100025#include "uidswap.h"
26#include "compat.h"
Damien Miller450a7a12000-03-26 13:04:51 +100027#include "key.h"
Damien Millereba71ba2000-04-29 23:57:08 +100028#include "sshconnect.h"
Damien Miller450a7a12000-03-26 13:04:51 +100029#include "hostfile.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000030#include "log.h"
31#include "readconf.h"
32#include "atomicio.h"
33#include "misc.h"
Damien Miller49d795c2002-01-22 23:34:12 +110034#include "readpass.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100035
Damien Millereba71ba2000-04-29 23:57:08 +100036char *client_version_string = NULL;
37char *server_version_string = NULL;
Damien Miller1383bd82000-04-06 12:32:37 +100038
Ben Lindstromf9c48842002-06-11 16:37:51 +000039/* import */
Damien Milleraae6c611999-12-06 11:47:28 +110040extern Options options;
Damien Miller34132e52000-01-14 15:45:46 +110041extern char *__progname;
Ben Lindstromf9c48842002-06-11 16:37:51 +000042extern uid_t original_real_uid;
43extern uid_t original_effective_uid;
Damien Milleraae6c611999-12-06 11:47:28 +110044
Tim Ricee991e3c2001-08-07 15:29:07 -070045#ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
46#define INET6_ADDRSTRLEN 46
47#endif
48
Ben Lindstromf9cedb92001-08-06 21:07:11 +000049static const char *
Ben Lindstrom18a32a72002-06-11 15:46:34 +000050sockaddr_ntop(struct sockaddr *sa, socklen_t salen)
Ben Lindstromf9cedb92001-08-06 21:07:11 +000051{
Ben Lindstrom159ac2e2002-06-09 20:14:54 +000052 static char addrbuf[NI_MAXHOST];
Ben Lindstromf9cedb92001-08-06 21:07:11 +000053
Ben Lindstrom18a32a72002-06-11 15:46:34 +000054 if (getnameinfo(sa, salen, addrbuf, sizeof(addrbuf), NULL, 0,
Ben Lindstrom159ac2e2002-06-09 20:14:54 +000055 NI_NUMERICHOST) != 0)
Ben Lindstrom2749e1c2002-06-09 20:16:22 +000056 fatal("sockaddr_ntop: getnameinfo NI_NUMERICHOST failed");
Ben Lindstromf9cedb92001-08-06 21:07:11 +000057 return addrbuf;
58}
59
Damien Miller95def091999-11-25 00:26:21 +110060/*
61 * Connect to the given ssh server using a proxy command.
62 */
Ben Lindstrombba81212001-06-25 05:01:22 +000063static int
Ben Lindstromf9c48842002-06-11 16:37:51 +000064ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100065{
Damien Miller95def091999-11-25 00:26:21 +110066 Buffer command;
67 const char *cp;
68 char *command_string;
69 int pin[2], pout[2];
Damien Miller166fca82000-04-20 07:42:21 +100070 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +110071 char strport[NI_MAXSERV];
Damien Millerd4a8b7e1999-10-27 13:42:43 +100072
Damien Miller95def091999-11-25 00:26:21 +110073 /* Convert the port number into a string. */
Damien Miller34132e52000-01-14 15:45:46 +110074 snprintf(strport, sizeof strport, "%hu", port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100075
Damien Miller95def091999-11-25 00:26:21 +110076 /* Build the final command string in the buffer by making the
77 appropriate substitutions to the given proxy command. */
78 buffer_init(&command);
79 for (cp = proxy_command; *cp; cp++) {
80 if (cp[0] == '%' && cp[1] == '%') {
81 buffer_append(&command, "%", 1);
82 cp++;
83 continue;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100084 }
Damien Miller95def091999-11-25 00:26:21 +110085 if (cp[0] == '%' && cp[1] == 'h') {
86 buffer_append(&command, host, strlen(host));
87 cp++;
88 continue;
89 }
90 if (cp[0] == '%' && cp[1] == 'p') {
Damien Miller34132e52000-01-14 15:45:46 +110091 buffer_append(&command, strport, strlen(strport));
Damien Miller95def091999-11-25 00:26:21 +110092 cp++;
93 continue;
94 }
95 buffer_append(&command, cp, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100096 }
Damien Miller95def091999-11-25 00:26:21 +110097 buffer_append(&command, "\0", 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100098
Damien Miller95def091999-11-25 00:26:21 +110099 /* Get the final command string. */
100 command_string = buffer_ptr(&command);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000101
Damien Miller95def091999-11-25 00:26:21 +1100102 /* Create pipes for communicating with the proxy. */
103 if (pipe(pin) < 0 || pipe(pout) < 0)
104 fatal("Could not create pipes to communicate with the proxy: %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100105 strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000106
Damien Miller95def091999-11-25 00:26:21 +1100107 debug("Executing proxy command: %.500s", command_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000108
Damien Miller95def091999-11-25 00:26:21 +1100109 /* Fork and execute the proxy command. */
110 if ((pid = fork()) == 0) {
111 char *argv[10];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000112
Damien Miller95def091999-11-25 00:26:21 +1100113 /* Child. Permanently give up superuser privileges. */
Ben Lindstromf9c48842002-06-11 16:37:51 +0000114 seteuid(original_real_uid);
115 setuid(original_real_uid);
Damien Miller95def091999-11-25 00:26:21 +1100116
117 /* Redirect stdin and stdout. */
118 close(pin[1]);
119 if (pin[0] != 0) {
120 if (dup2(pin[0], 0) < 0)
121 perror("dup2 stdin");
122 close(pin[0]);
123 }
124 close(pout[0]);
125 if (dup2(pout[1], 1) < 0)
126 perror("dup2 stdout");
127 /* Cannot be 1 because pin allocated two descriptors. */
128 close(pout[1]);
129
130 /* Stderr is left as it is so that error messages get
131 printed on the user's terminal. */
Damien Miller7b413d22000-07-01 13:24:21 +1000132 argv[0] = _PATH_BSHELL;
Damien Miller95def091999-11-25 00:26:21 +1100133 argv[1] = "-c";
134 argv[2] = command_string;
135 argv[3] = NULL;
136
137 /* Execute the proxy command. Note that we gave up any
138 extra privileges above. */
Kevin Stevesfcd5d602001-01-07 11:45:22 +0000139 execv(argv[0], argv);
140 perror(argv[0]);
Damien Miller95def091999-11-25 00:26:21 +1100141 exit(1);
142 }
143 /* Parent. */
144 if (pid < 0)
145 fatal("fork failed: %.100s", strerror(errno));
146
147 /* Close child side of the descriptors. */
148 close(pin[0]);
149 close(pout[1]);
150
151 /* Free the command name. */
152 buffer_free(&command);
153
154 /* Set the connection file descriptors. */
155 packet_set_connection(pout[0], pin[1]);
156
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000157 /* Indicate OK return */
158 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000159}
160
Damien Miller95def091999-11-25 00:26:21 +1100161/*
162 * Creates a (possibly privileged) socket for use as the ssh connection.
163 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000164static int
Ben Lindstromf9c48842002-06-11 16:37:51 +0000165ssh_create_socket(int privileged, int family)
Damien Miller95def091999-11-25 00:26:21 +1100166{
Ben Lindstrome0f88042001-04-30 13:06:24 +0000167 int sock, gaierr;
168 struct addrinfo hints, *res;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000169
Damien Miller5428f641999-11-25 11:54:57 +1100170 /*
171 * If we are running as root and want to connect to a privileged
172 * port, bind our own socket to a privileged port.
173 */
Damien Miller95def091999-11-25 00:26:21 +1100174 if (privileged) {
175 int p = IPPORT_RESERVED - 1;
Ben Lindstromf9c48842002-06-11 16:37:51 +0000176 PRIV_START;
Damien Miller34132e52000-01-14 15:45:46 +1100177 sock = rresvport_af(&p, family);
Ben Lindstromf9c48842002-06-11 16:37:51 +0000178 PRIV_END;
Damien Miller95def091999-11-25 00:26:21 +1100179 if (sock < 0)
Damien Miller98c7ad62000-03-09 21:27:49 +1100180 error("rresvport: af=%d %.100s", family, strerror(errno));
181 else
182 debug("Allocated local port %d.", p);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000183 return sock;
Damien Miller95def091999-11-25 00:26:21 +1100184 }
Ben Lindstrome0f88042001-04-30 13:06:24 +0000185 sock = socket(family, SOCK_STREAM, 0);
186 if (sock < 0)
187 error("socket: %.100s", strerror(errno));
Ben Lindstrome0f88042001-04-30 13:06:24 +0000188
189 /* Bind the socket to an alternative local IP address */
190 if (options.bind_address == NULL)
191 return sock;
192
193 memset(&hints, 0, sizeof(hints));
Damien Miller7ea6f202001-10-10 15:04:41 +1000194 hints.ai_family = family;
Ben Lindstrome0f88042001-04-30 13:06:24 +0000195 hints.ai_socktype = SOCK_STREAM;
196 hints.ai_flags = AI_PASSIVE;
197 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
198 if (gaierr) {
199 error("getaddrinfo: %s: %s", options.bind_address,
200 gai_strerror(gaierr));
201 close(sock);
202 return -1;
203 }
204 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
205 error("bind: %s: %s", options.bind_address, strerror(errno));
206 close(sock);
207 freeaddrinfo(res);
208 return -1;
209 }
210 freeaddrinfo(res);
Damien Miller95def091999-11-25 00:26:21 +1100211 return sock;
212}
213
214/*
Damien Miller34132e52000-01-14 15:45:46 +1100215 * Opens a TCP/IP connection to the remote server on the given host.
216 * The address of the remote host will be returned in hostaddr.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000217 * If port is 0, the default port will be used. If needpriv is true,
Damien Miller95def091999-11-25 00:26:21 +1100218 * a privileged port will be allocated to make the connection.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000219 * This requires super-user privileges if needpriv is true.
Damien Miller95def091999-11-25 00:26:21 +1100220 * Connection_attempts specifies the maximum number of tries (one per
221 * second). If proxy_command is non-NULL, it specifies the command (with %h
222 * and %p substituted for host and port, respectively) to use to contact
223 * the daemon.
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000224 * Return values:
225 * 0 for OK
226 * ECONNREFUSED if we got a "Connection Refused" by the peer on any address
227 * ECONNABORTED if we failed without a "Connection refused"
228 * Suitable error messages for the connection failure will already have been
229 * printed.
Damien Miller95def091999-11-25 00:26:21 +1100230 */
231int
Damien Miller34132e52000-01-14 15:45:46 +1100232ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
Damien Miller139d4cd2001-10-10 15:07:44 +1000233 u_short port, int family, int connection_attempts,
Ben Lindstromf9c48842002-06-11 16:37:51 +0000234 int needpriv, const char *proxy_command)
Damien Miller95def091999-11-25 00:26:21 +1100235{
Damien Miller34132e52000-01-14 15:45:46 +1100236 int gaierr;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000237 int on = 1;
238 int sock = -1, attempt;
239 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
240 struct addrinfo hints, *ai, *aitop;
Damien Miller95def091999-11-25 00:26:21 +1100241 struct linger linger;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000242 struct servent *sp;
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000243 /*
244 * Did we get only other errors than "Connection refused" (which
245 * should block fallback to rsh and similar), or did we get at least
246 * one "Connection refused"?
247 */
248 int full_failure = 1;
Damien Miller95def091999-11-25 00:26:21 +1100249
Ben Lindstromf9c48842002-06-11 16:37:51 +0000250 debug("ssh_connect: needpriv %d", needpriv);
Damien Miller95def091999-11-25 00:26:21 +1100251
252 /* Get default port if port has not been set. */
253 if (port == 0) {
254 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
255 if (sp)
256 port = ntohs(sp->s_port);
257 else
258 port = SSH_DEFAULT_PORT;
259 }
260 /* If a proxy command is given, connect using it. */
261 if (proxy_command != NULL)
Ben Lindstromf9c48842002-06-11 16:37:51 +0000262 return ssh_proxy_connect(host, port, proxy_command);
Damien Miller95def091999-11-25 00:26:21 +1100263
264 /* No proxy command. */
265
Damien Miller34132e52000-01-14 15:45:46 +1100266 memset(&hints, 0, sizeof(hints));
Damien Miller139d4cd2001-10-10 15:07:44 +1000267 hints.ai_family = family;
Damien Miller34132e52000-01-14 15:45:46 +1100268 hints.ai_socktype = SOCK_STREAM;
Ben Lindstrom5c385522002-06-23 21:23:20 +0000269 snprintf(strport, sizeof strport, "%u", port);
Damien Miller34132e52000-01-14 15:45:46 +1100270 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
271 fatal("%s: %.100s: %s", __progname, host,
272 gai_strerror(gaierr));
Damien Miller95def091999-11-25 00:26:21 +1100273
Damien Millera34a28b1999-12-14 10:47:15 +1100274 /*
275 * Try to connect several times. On some machines, the first time
276 * will sometimes fail. In general socket code appears to behave
277 * quite magically on many machines.
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000278 */
279 for (attempt = 0; ;) {
Damien Miller95def091999-11-25 00:26:21 +1100280 if (attempt > 0)
281 debug("Trying again...");
282
Damien Miller34132e52000-01-14 15:45:46 +1100283 /* Loop through addresses for this host, and try each one in
Damien Miller4af51302000-04-16 11:18:38 +1000284 sequence until the connection succeeds. */
Damien Miller34132e52000-01-14 15:45:46 +1100285 for (ai = aitop; ai; ai = ai->ai_next) {
286 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
287 continue;
288 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
289 ntop, sizeof(ntop), strport, sizeof(strport),
290 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
291 error("ssh_connect: getnameinfo failed");
292 continue;
293 }
294 debug("Connecting to %.200s [%.100s] port %s.",
295 host, ntop, strport);
Damien Miller95def091999-11-25 00:26:21 +1100296
Damien Miller34132e52000-01-14 15:45:46 +1100297 /* Create a socket for connecting. */
Ben Lindstromf9c48842002-06-11 16:37:51 +0000298 sock = ssh_create_socket(needpriv, ai->ai_family);
Damien Miller34132e52000-01-14 15:45:46 +1100299 if (sock < 0)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000300 /* Any error is already output */
Damien Miller34132e52000-01-14 15:45:46 +1100301 continue;
Damien Miller95def091999-11-25 00:26:21 +1100302
Damien Miller34132e52000-01-14 15:45:46 +1100303 if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
304 /* Successful connection. */
Ben Lindstroma3700052001-04-05 23:26:32 +0000305 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
Damien Miller95def091999-11-25 00:26:21 +1100306 break;
Damien Miller34132e52000-01-14 15:45:46 +1100307 } else {
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000308 if (errno == ECONNREFUSED)
309 full_failure = 0;
310 log("ssh: connect to address %s port %s: %s",
Ben Lindstrom18a32a72002-06-11 15:46:34 +0000311 sockaddr_ntop(ai->ai_addr, ai->ai_addrlen),
312 strport, strerror(errno));
Damien Miller5428f641999-11-25 11:54:57 +1100313 /*
314 * Close the failed socket; there appear to
315 * be some problems when reusing a socket for
316 * which connect() has already returned an
317 * error.
318 */
Damien Miller95def091999-11-25 00:26:21 +1100319 close(sock);
320 }
Damien Miller95def091999-11-25 00:26:21 +1100321 }
Damien Miller34132e52000-01-14 15:45:46 +1100322 if (ai)
323 break; /* Successful connection. */
Damien Miller95def091999-11-25 00:26:21 +1100324
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000325 attempt++;
326 if (attempt >= connection_attempts)
327 break;
Damien Miller95def091999-11-25 00:26:21 +1100328 /* Sleep a moment before retrying. */
329 sleep(1);
330 }
Damien Miller34132e52000-01-14 15:45:46 +1100331
332 freeaddrinfo(aitop);
333
Damien Miller95def091999-11-25 00:26:21 +1100334 /* Return failure if we didn't get a successful connection. */
335 if (attempt >= connection_attempts)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000336 return full_failure ? ECONNABORTED : ECONNREFUSED;
Damien Miller95def091999-11-25 00:26:21 +1100337
338 debug("Connection established.");
339
Damien Miller5428f641999-11-25 11:54:57 +1100340 /*
341 * Set socket options. We would like the socket to disappear as soon
342 * as it has been closed for whatever reason.
343 */
344 /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
Damien Miller95def091999-11-25 00:26:21 +1100345 linger.l_onoff = 1;
346 linger.l_linger = 5;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000347 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
348
349 /* Set keepalives if requested. */
350 if (options.keepalives &&
351 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
352 sizeof(on)) < 0)
353 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100354
355 /* Set the connection. */
356 packet_set_connection(sock, sock);
357
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000358 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100359}
360
Damien Milleraae6c611999-12-06 11:47:28 +1100361/*
Damien Miller95def091999-11-25 00:26:21 +1100362 * Waits for the server identification string, and sends our own
363 * identification string.
364 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000365static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000366ssh_exchange_identification(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000367{
Damien Miller95def091999-11-25 00:26:21 +1100368 char buf[256], remote_version[256]; /* must be same size! */
Damien Miller78928792000-04-12 20:17:38 +1000369 int remote_major, remote_minor, i, mismatch;
Damien Miller95def091999-11-25 00:26:21 +1100370 int connection_in = packet_get_connection_in();
371 int connection_out = packet_get_connection_out();
Kevin Stevesef4eea92001-02-05 12:42:17 +0000372 int minor1 = PROTOCOL_MINOR_1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000373
Damien Miller95def091999-11-25 00:26:21 +1100374 /* Read other side\'s version identification. */
Damien Millerf6d9e222000-06-18 14:50:44 +1000375 for (;;) {
376 for (i = 0; i < sizeof(buf) - 1; i++) {
377 int len = atomicio(read, connection_in, &buf[i], 1);
378 if (len < 0)
379 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
380 if (len != 1)
381 fatal("ssh_exchange_identification: Connection closed by remote host");
382 if (buf[i] == '\r') {
383 buf[i] = '\n';
384 buf[i + 1] = 0;
385 continue; /**XXX wait for \n */
386 }
387 if (buf[i] == '\n') {
388 buf[i + 1] = 0;
389 break;
390 }
Damien Miller95def091999-11-25 00:26:21 +1100391 }
Damien Millerf6d9e222000-06-18 14:50:44 +1000392 buf[sizeof(buf) - 1] = 0;
393 if (strncmp(buf, "SSH-", 4) == 0)
Damien Miller95def091999-11-25 00:26:21 +1100394 break;
Damien Millerf6d9e222000-06-18 14:50:44 +1000395 debug("ssh_exchange_identification: %s", buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000396 }
Damien Miller1383bd82000-04-06 12:32:37 +1000397 server_version_string = xstrdup(buf);
Damien Miller95def091999-11-25 00:26:21 +1100398
Damien Miller5428f641999-11-25 11:54:57 +1100399 /*
400 * Check that the versions match. In future this might accept
401 * several versions and set appropriate flags to handle them.
402 */
Damien Miller1383bd82000-04-06 12:32:37 +1000403 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
404 &remote_major, &remote_minor, remote_version) != 3)
Damien Miller95def091999-11-25 00:26:21 +1100405 fatal("Bad remote protocol version identification: '%.100s'", buf);
406 debug("Remote protocol version %d.%d, remote software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100407 remote_major, remote_minor, remote_version);
Damien Miller95def091999-11-25 00:26:21 +1100408
Damien Miller1383bd82000-04-06 12:32:37 +1000409 compat_datafellows(remote_version);
Damien Miller78928792000-04-12 20:17:38 +1000410 mismatch = 0;
Damien Miller1383bd82000-04-06 12:32:37 +1000411
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000412 switch (remote_major) {
Damien Miller78928792000-04-12 20:17:38 +1000413 case 1:
414 if (remote_minor == 99 &&
415 (options.protocol & SSH_PROTO_2) &&
416 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
417 enable_compat20();
418 break;
Damien Miller95def091999-11-25 00:26:21 +1100419 }
Damien Miller78928792000-04-12 20:17:38 +1000420 if (!(options.protocol & SSH_PROTO_1)) {
421 mismatch = 1;
422 break;
423 }
424 if (remote_minor < 3) {
425 fatal("Remote machine has too old SSH software version.");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100426 } else if (remote_minor == 3 || remote_minor == 4) {
Damien Miller78928792000-04-12 20:17:38 +1000427 /* We speak 1.3, too. */
428 enable_compat13();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100429 minor1 = 3;
Damien Miller78928792000-04-12 20:17:38 +1000430 if (options.forward_agent) {
431 log("Agent forwarding disabled for protocol 1.3");
432 options.forward_agent = 0;
433 }
434 }
435 break;
436 case 2:
437 if (options.protocol & SSH_PROTO_2) {
438 enable_compat20();
439 break;
440 }
441 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000442 default:
Damien Miller78928792000-04-12 20:17:38 +1000443 mismatch = 1;
444 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000445 }
Damien Miller78928792000-04-12 20:17:38 +1000446 if (mismatch)
Damien Miller95def091999-11-25 00:26:21 +1100447 fatal("Protocol major versions differ: %d vs. %d",
Damien Miller78928792000-04-12 20:17:38 +1000448 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
449 remote_major);
Damien Miller95def091999-11-25 00:26:21 +1100450 /* Send our own protocol version identification. */
451 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
Damien Miller78928792000-04-12 20:17:38 +1000452 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
Damien Miller0bc1bd82000-11-13 22:57:25 +1100453 compat20 ? PROTOCOL_MINOR_2 : minor1,
Damien Miller1383bd82000-04-06 12:32:37 +1000454 SSH_VERSION);
Damien Miller037a0dc1999-12-07 15:38:31 +1100455 if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
Damien Miller95def091999-11-25 00:26:21 +1100456 fatal("write: %.100s", strerror(errno));
Damien Miller1383bd82000-04-06 12:32:37 +1000457 client_version_string = xstrdup(buf);
458 chop(client_version_string);
459 chop(server_version_string);
460 debug("Local version string %.100s", client_version_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000461}
462
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000463/* defaults to 'no' */
Ben Lindstrombba81212001-06-25 05:01:22 +0000464static int
Damien Millere3980042001-10-10 15:02:03 +1000465confirm(const char *prompt)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000466{
Damien Miller49d795c2002-01-22 23:34:12 +1100467 const char *msg, *again = "Please type 'yes' or 'no': ";
468 char *p;
469 int ret = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000470
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000471 if (options.batch_mode)
472 return 0;
Damien Miller49d795c2002-01-22 23:34:12 +1100473 for (msg = prompt;;msg = again) {
474 p = read_passphrase(msg, RP_ECHO);
475 if (p == NULL ||
476 (p[0] == '\0') || (p[0] == '\n') ||
477 strncasecmp(p, "no", 2) == 0)
478 ret = 0;
479 if (strncasecmp(p, "yes", 3) == 0)
480 ret = 1;
481 if (p)
482 xfree(p);
483 if (ret != -1)
484 return ret;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000485 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000486}
487
Damien Miller95def091999-11-25 00:26:21 +1100488/*
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000489 * check whether the supplied host key is valid, return -1 if the key
490 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
Damien Miller95def091999-11-25 00:26:21 +1100491 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000492static int
Damien Millereba71ba2000-04-29 23:57:08 +1000493check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000494 int readonly, const char *user_hostfile, const char *system_hostfile)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000495{
Damien Miller450a7a12000-03-26 13:04:51 +1000496 Key *file_key;
Damien Millere247cc42000-05-07 12:03:14 +1000497 char *type = key_type(host_key);
Damien Millera34a28b1999-12-14 10:47:15 +1100498 char *ip = NULL;
Ben Lindstromcfccef92001-03-13 04:57:58 +0000499 char hostline[1000], *hostp, *fp;
Damien Miller95def091999-11-25 00:26:21 +1100500 HostStatus host_status;
501 HostStatus ip_status;
Damien Miller34132e52000-01-14 15:45:46 +1100502 int local = 0, host_ip_differ = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100503 int salen;
Damien Miller34132e52000-01-14 15:45:46 +1100504 char ntop[NI_MAXHOST];
Damien Miller49d795c2002-01-22 23:34:12 +1100505 char msg[1024];
506 int len, host_line, ip_line;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000507 const char *host_file = NULL, *ip_file = NULL;
Damien Miller34132e52000-01-14 15:45:46 +1100508
509 /*
510 * Force accepting of the host key for loopback/localhost. The
511 * problem is that if the home directory is NFS-mounted to multiple
512 * machines, localhost will refer to a different machine in each of
513 * them, and the user will get bogus HOST_CHANGED warnings. This
514 * essentially disables host authentication for localhost; however,
515 * this is probably not a real problem.
516 */
Damien Millereba71ba2000-04-29 23:57:08 +1000517 /** hostaddr == 0! */
Damien Miller34132e52000-01-14 15:45:46 +1100518 switch (hostaddr->sa_family) {
519 case AF_INET:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000520 local = (ntohl(((struct sockaddr_in *)hostaddr)->
Kevin Steves399ec972002-03-05 18:59:45 +0000521 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
Damien Millereaf99942000-01-19 13:45:07 +1100522 salen = sizeof(struct sockaddr_in);
Damien Miller34132e52000-01-14 15:45:46 +1100523 break;
524 case AF_INET6:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000525 local = IN6_IS_ADDR_LOOPBACK(
526 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
Damien Millereaf99942000-01-19 13:45:07 +1100527 salen = sizeof(struct sockaddr_in6);
Damien Miller34132e52000-01-14 15:45:46 +1100528 break;
529 default:
530 local = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100531 salen = sizeof(struct sockaddr_storage);
Damien Miller34132e52000-01-14 15:45:46 +1100532 break;
533 }
Ben Lindstrom3cecc9a2001-10-03 17:39:38 +0000534 if (options.no_host_authentication_for_localhost == 1 && local &&
535 options.host_key_alias == NULL) {
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000536 debug("Forcing accepting of host key for "
537 "loopback/localhost.");
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000538 return 0;
Damien Miller34132e52000-01-14 15:45:46 +1100539 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000540
Damien Milleraae6c611999-12-06 11:47:28 +1100541 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000542 * We don't have the remote ip-address for connections
543 * using a proxy command
Damien Milleraae6c611999-12-06 11:47:28 +1100544 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000545 if (options.proxy_command == NULL) {
546 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
547 NULL, 0, NI_NUMERICHOST) != 0)
548 fatal("check_host_key: getnameinfo failed");
549 ip = xstrdup(ntop);
550 } else {
551 ip = xstrdup("<no hostip for proxy command>");
552 }
553 /*
554 * Turn off check_host_ip if the connection is to localhost, via proxy
555 * command or if we don't have a hostname to compare with
556 */
557 if (options.check_host_ip &&
558 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
Damien Milleraae6c611999-12-06 11:47:28 +1100559 options.check_host_ip = 0;
560
Damien Millera34a28b1999-12-14 10:47:15 +1100561 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000562 * Allow the user to record the key under a different name. This is
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000563 * useful for ssh tunneling over forwarded connections or if you run
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000564 * multiple sshd's on different ports on the same machine.
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000565 */
566 if (options.host_key_alias != NULL) {
567 host = options.host_key_alias;
568 debug("using hostkeyalias: %s", host);
569 }
570
571 /*
Damien Millera34a28b1999-12-14 10:47:15 +1100572 * Store the host key from the known host file in here so that we can
573 * compare it with the key for the IP address.
574 */
Damien Miller450a7a12000-03-26 13:04:51 +1000575 file_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000576
Damien Miller5428f641999-11-25 11:54:57 +1100577 /*
578 * Check if the host key is present in the user\'s list of known
579 * hosts or in the systemwide list.
580 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000581 host_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000582 host_status = check_host_in_hostfile(host_file, host, host_key,
Damien Miller9f0f5c62001-12-21 14:45:46 +1100583 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000584 if (host_status == HOST_NEW) {
585 host_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000586 host_status = check_host_in_hostfile(host_file, host, host_key,
587 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000588 }
Damien Miller5428f641999-11-25 11:54:57 +1100589 /*
Damien Miller5428f641999-11-25 11:54:57 +1100590 * Also perform check for the ip address, skip the check if we are
591 * localhost or the hostname was an ip address to begin with
592 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000593 if (options.check_host_ip) {
Damien Miller450a7a12000-03-26 13:04:51 +1000594 Key *ip_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000595
Ben Lindstrom46c16222000-12-22 01:43:59 +0000596 ip_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000597 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
598 ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000599 if (ip_status == HOST_NEW) {
600 ip_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000601 ip_status = check_host_in_hostfile(ip_file, ip,
602 host_key, ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000603 }
Damien Miller95def091999-11-25 00:26:21 +1100604 if (host_status == HOST_CHANGED &&
Damien Miller450a7a12000-03-26 13:04:51 +1000605 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
Damien Miller95def091999-11-25 00:26:21 +1100606 host_ip_differ = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000607
Damien Miller450a7a12000-03-26 13:04:51 +1000608 key_free(ip_key);
Damien Miller95def091999-11-25 00:26:21 +1100609 } else
610 ip_status = host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000611
Damien Miller450a7a12000-03-26 13:04:51 +1000612 key_free(file_key);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000613
Damien Miller95def091999-11-25 00:26:21 +1100614 switch (host_status) {
615 case HOST_OK:
616 /* The host is known and the key matches. */
Damien Millere247cc42000-05-07 12:03:14 +1000617 debug("Host '%.200s' is known and matches the %s host key.",
618 host, type);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000619 debug("Found key in %s:%d", host_file, host_line);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000620 if (options.check_host_ip && ip_status == HOST_NEW) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000621 if (readonly)
622 log("%s host key for IP address "
623 "'%.128s' not in list of known hosts.",
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000624 type, ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000625 else if (!add_host_to_hostfile(user_hostfile, ip,
Damien Miller9f0f5c62001-12-21 14:45:46 +1100626 host_key))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000627 log("Failed to add the %s host key for IP "
628 "address '%.128s' to the list of known "
629 "hosts (%.30s).", type, ip, user_hostfile);
630 else
631 log("Warning: Permanently added the %s host "
632 "key for IP address '%.128s' to the list "
633 "of known hosts.", type, ip);
Damien Miller95def091999-11-25 00:26:21 +1100634 }
635 break;
636 case HOST_NEW:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000637 if (readonly)
638 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100639 /* The host is new. */
640 if (options.strict_host_key_checking == 1) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000641 /*
642 * User has requested strict host key checking. We
643 * will not add the host key automatically. The only
644 * alternative left is to abort.
645 */
646 error("No %s host key is known for %.200s and you "
647 "have requested strict checking.", type, host);
648 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100649 } else if (options.strict_host_key_checking == 2) {
650 /* The default */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000651 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller49d795c2002-01-22 23:34:12 +1100652 snprintf(msg, sizeof(msg),
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000653 "The authenticity of host '%.200s (%s)' can't be "
654 "established.\n"
Damien Millere247cc42000-05-07 12:03:14 +1000655 "%s key fingerprint is %s.\n"
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000656 "Are you sure you want to continue connecting "
657 "(yes/no)? ", host, ip, type, fp);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000658 xfree(fp);
Damien Miller49d795c2002-01-22 23:34:12 +1100659 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000660 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100661 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000662 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Miller95def091999-11-25 00:26:21 +1100663 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
664 hostp = hostline;
665 } else
666 hostp = host;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000667
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000668 /*
669 * If not in strict mode, add the key automatically to the
670 * local known_hosts file.
671 */
Damien Millereba71ba2000-04-29 23:57:08 +1000672 if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000673 log("Failed to add the host to the list of known "
674 "hosts (%.500s).", user_hostfile);
Damien Miller95def091999-11-25 00:26:21 +1100675 else
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000676 log("Warning: Permanently added '%.200s' (%s) to the "
677 "list of known hosts.", hostp, type);
Damien Miller95def091999-11-25 00:26:21 +1100678 break;
679 case HOST_CHANGED:
680 if (options.check_host_ip && host_ip_differ) {
681 char *msg;
682 if (ip_status == HOST_NEW)
683 msg = "is unknown";
684 else if (ip_status == HOST_OK)
685 msg = "is unchanged";
686 else
687 msg = "has a different value";
688 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
689 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
690 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millere247cc42000-05-07 12:03:14 +1000691 error("The %s host key for %s has changed,", type, host);
Damien Miller95def091999-11-25 00:26:21 +1100692 error("and the key for the according IP address %s", ip);
693 error("%s. This could either mean that", msg);
694 error("DNS SPOOFING is happening or the IP address for the host");
Ben Lindstrom46c16222000-12-22 01:43:59 +0000695 error("and its host key have changed at the same time.");
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000696 if (ip_status != HOST_NEW)
Ben Lindstrom46c16222000-12-22 01:43:59 +0000697 error("Offending key for IP in %s:%d", ip_file, ip_line);
Damien Miller95def091999-11-25 00:26:21 +1100698 }
699 /* The host key has changed. */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000700 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller95def091999-11-25 00:26:21 +1100701 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millerf039bad1999-12-21 20:57:20 +1100702 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
Damien Miller95def091999-11-25 00:26:21 +1100703 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
704 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
705 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
Damien Millere247cc42000-05-07 12:03:14 +1000706 error("It is also possible that the %s host key has just been changed.", type);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000707 error("The fingerprint for the %s key sent by the remote host is\n%s.",
Ben Lindstromcfccef92001-03-13 04:57:58 +0000708 type, fp);
Damien Miller95def091999-11-25 00:26:21 +1100709 error("Please contact your system administrator.");
710 error("Add correct host key in %.100s to get rid of this message.",
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000711 user_hostfile);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000712 error("Offending key in %s:%d", host_file, host_line);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000713 xfree(fp);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000714
Damien Miller5428f641999-11-25 11:54:57 +1100715 /*
716 * If strict host key checking is in use, the user will have
717 * to edit the key manually and we can only abort.
718 */
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000719 if (options.strict_host_key_checking) {
720 error("%s host key for %.200s has changed and you have "
721 "requested strict checking.", type, host);
722 goto fail;
723 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000724
Damien Miller5428f641999-11-25 11:54:57 +1100725 /*
726 * If strict host key checking has not been requested, allow
727 * the connection but without password authentication or
728 * agent forwarding.
729 */
Damien Miller95def091999-11-25 00:26:21 +1100730 if (options.password_authentication) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000731 error("Password authentication is disabled to avoid "
732 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100733 options.password_authentication = 0;
734 }
735 if (options.forward_agent) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000736 error("Agent forwarding is disabled to avoid "
737 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100738 options.forward_agent = 0;
739 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000740 if (options.forward_x11) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000741 error("X11 forwarding is disabled to avoid "
742 "man-in-the-middle attacks.");
Ben Lindstromc72745a2000-12-02 19:03:54 +0000743 options.forward_x11 = 0;
744 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000745 if (options.num_local_forwards > 0 ||
746 options.num_remote_forwards > 0) {
747 error("Port forwarding is disabled to avoid "
748 "man-in-the-middle attacks.");
749 options.num_local_forwards =
Damien Miller9f0f5c62001-12-21 14:45:46 +1100750 options.num_remote_forwards = 0;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000751 }
Damien Miller5428f641999-11-25 11:54:57 +1100752 /*
753 * XXX Should permit the user to change to use the new id.
754 * This could be done by converting the host key to an
755 * identifying sentence, tell that the host identifies itself
756 * by that sentence, and ask the user if he/she whishes to
757 * accept the authentication.
758 */
Damien Miller95def091999-11-25 00:26:21 +1100759 break;
760 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000761
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000762 if (options.check_host_ip && host_status != HOST_CHANGED &&
763 ip_status == HOST_CHANGED) {
Damien Miller49d795c2002-01-22 23:34:12 +1100764 snprintf(msg, sizeof(msg),
765 "Warning: the %s host key for '%.200s' "
766 "differs from the key for the IP address '%.128s'"
767 "\nOffending key for IP in %s:%d",
768 type, host, ip, ip_file, ip_line);
769 if (host_status == HOST_OK) {
770 len = strlen(msg);
771 snprintf(msg + len, sizeof(msg) - len,
772 "\nMatching host key in %s:%d",
Ben Lindstromcb72e4f2002-06-21 00:41:51 +0000773 host_file, host_line);
Damien Miller49d795c2002-01-22 23:34:12 +1100774 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000775 if (options.strict_host_key_checking == 1) {
Damien Miller49d795c2002-01-22 23:34:12 +1100776 log(msg);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000777 error("Exiting, you have requested strict checking.");
778 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000779 } else if (options.strict_host_key_checking == 2) {
Damien Miller49d795c2002-01-22 23:34:12 +1100780 strlcat(msg, "\nAre you sure you want "
781 "to continue connecting (yes/no)? ", sizeof(msg));
782 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000783 goto fail;
Damien Miller49d795c2002-01-22 23:34:12 +1100784 } else {
785 log(msg);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000786 }
787 }
788
Ben Lindstromc72745a2000-12-02 19:03:54 +0000789 xfree(ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000790 return 0;
791
792fail:
793 xfree(ip);
794 return -1;
795}
796
797int
798verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
799{
800 struct stat st;
801
802 /* return ok if the key can be found in an old keyfile */
803 if (stat(options.system_hostfile2, &st) == 0 ||
804 stat(options.user_hostfile2, &st) == 0) {
805 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
806 options.user_hostfile2, options.system_hostfile2) == 0)
807 return 0;
808 }
809 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
810 options.user_hostfile, options.system_hostfile);
Damien Millera34a28b1999-12-14 10:47:15 +1100811}
Damien Miller037a0dc1999-12-07 15:38:31 +1100812
Damien Miller396691a2000-01-20 22:44:08 +1100813/*
814 * Starts a dialog with the server, and authenticates the current user on the
815 * server. This does not need any extra privileges. The basic connection
816 * to the server must already have been established before this is called.
817 * If login fails, this function prints an error and never returns.
818 * This function does not require super-user privileges.
819 */
820void
Ben Lindstrom1bad2562002-06-06 19:57:33 +0000821ssh_login(Sensitive *sensitive, const char *orighost,
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000822 struct sockaddr *hostaddr, struct passwd *pw)
Damien Miller396691a2000-01-20 22:44:08 +1100823{
824 char *host, *cp;
Damien Millereba71ba2000-04-29 23:57:08 +1000825 char *server_user, *local_user;
826
Damien Millereba71ba2000-04-29 23:57:08 +1000827 local_user = xstrdup(pw->pw_name);
828 server_user = options.user ? options.user : local_user;
Damien Miller396691a2000-01-20 22:44:08 +1100829
830 /* Convert the user-supplied hostname into all lowercase. */
831 host = xstrdup(orighost);
832 for (cp = host; *cp; cp++)
833 if (isupper(*cp))
834 *cp = tolower(*cp);
835
836 /* Exchange protocol version identification strings with the server. */
837 ssh_exchange_identification();
838
839 /* Put the connection into non-blocking mode. */
840 packet_set_nonblocking();
841
Damien Miller396691a2000-01-20 22:44:08 +1100842 /* key exchange */
Damien Miller396691a2000-01-20 22:44:08 +1100843 /* authenticate user */
Damien Miller1383bd82000-04-06 12:32:37 +1000844 if (compat20) {
845 ssh_kex2(host, hostaddr);
Ben Lindstrom1bad2562002-06-06 19:57:33 +0000846 ssh_userauth2(local_user, server_user, host, sensitive);
Damien Miller1383bd82000-04-06 12:32:37 +1000847 } else {
Damien Miller1383bd82000-04-06 12:32:37 +1000848 ssh_kex(host, hostaddr);
Ben Lindstrom1bad2562002-06-06 19:57:33 +0000849 ssh_userauth1(local_user, server_user, host, sensitive);
Damien Miller1383bd82000-04-06 12:32:37 +1000850 }
Damien Miller396691a2000-01-20 22:44:08 +1100851}
Damien Miller79438cc2001-02-16 12:34:57 +1100852
853void
854ssh_put_password(char *password)
855{
856 int size;
857 char *padded;
858
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000859 if (datafellows & SSH_BUG_PASSWORDPAD) {
Ben Lindstrom664408d2001-06-09 01:42:01 +0000860 packet_put_cstring(password);
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000861 return;
862 }
Damien Miller79438cc2001-02-16 12:34:57 +1100863 size = roundup(strlen(password) + 1, 32);
864 padded = xmalloc(size);
865 memset(padded, 0, size);
866 strlcpy(padded, password, size);
867 packet_put_string(padded, size);
868 memset(padded, 0, size);
869 xfree(padded);
870}