blob: 776d72065579604979cba8ed1cd4f76d8b3e9775 [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"
Damien Miller8c4e18a2002-09-19 12:05:02 +100016RCSID("$OpenBSD: sshconnect.c,v 1.135 2002/09/19 01:58:18 djm 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 Miller8c4e18a2002-09-19 12:05:02 +100044extern pid_t proxy_command_pid;
Damien Milleraae6c611999-12-06 11:47:28 +110045
Tim Ricee991e3c2001-08-07 15:29:07 -070046#ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
47#define INET6_ADDRSTRLEN 46
48#endif
49
Ben Lindstrom3ed66402002-08-01 01:21:56 +000050static int show_other_keys(const char *, Key *);
51
Damien Miller95def091999-11-25 00:26:21 +110052/*
53 * Connect to the given ssh server using a proxy command.
54 */
Ben Lindstrombba81212001-06-25 05:01:22 +000055static int
Ben Lindstromf9c48842002-06-11 16:37:51 +000056ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
Damien Millerd4a8b7e1999-10-27 13:42:43 +100057{
Damien Miller95def091999-11-25 00:26:21 +110058 Buffer command;
59 const char *cp;
60 char *command_string;
61 int pin[2], pout[2];
Damien Miller166fca82000-04-20 07:42:21 +100062 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +110063 char strport[NI_MAXSERV];
Damien Millerd4a8b7e1999-10-27 13:42:43 +100064
Damien Miller95def091999-11-25 00:26:21 +110065 /* Convert the port number into a string. */
Damien Miller34132e52000-01-14 15:45:46 +110066 snprintf(strport, sizeof strport, "%hu", port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100067
Damien Miller8c4e18a2002-09-19 12:05:02 +100068 /*
69 * Build the final command string in the buffer by making the
70 * appropriate substitutions to the given proxy command.
71 *
72 * Use "exec" to avoid "sh -c" processes on some platforms
73 * (e.g. Solaris)
74 */
Damien Miller95def091999-11-25 00:26:21 +110075 buffer_init(&command);
Damien Miller8c4e18a2002-09-19 12:05:02 +100076 buffer_append(&command, "exec ", 5);
77
Damien Miller95def091999-11-25 00:26:21 +110078 for (cp = proxy_command; *cp; cp++) {
79 if (cp[0] == '%' && cp[1] == '%') {
80 buffer_append(&command, "%", 1);
81 cp++;
82 continue;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100083 }
Damien Miller95def091999-11-25 00:26:21 +110084 if (cp[0] == '%' && cp[1] == 'h') {
85 buffer_append(&command, host, strlen(host));
86 cp++;
87 continue;
88 }
89 if (cp[0] == '%' && cp[1] == 'p') {
Damien Miller34132e52000-01-14 15:45:46 +110090 buffer_append(&command, strport, strlen(strport));
Damien Miller95def091999-11-25 00:26:21 +110091 cp++;
92 continue;
93 }
94 buffer_append(&command, cp, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100095 }
Damien Miller95def091999-11-25 00:26:21 +110096 buffer_append(&command, "\0", 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100097
Damien Miller95def091999-11-25 00:26:21 +110098 /* Get the final command string. */
99 command_string = buffer_ptr(&command);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000100
Damien Miller95def091999-11-25 00:26:21 +1100101 /* Create pipes for communicating with the proxy. */
102 if (pipe(pin) < 0 || pipe(pout) < 0)
103 fatal("Could not create pipes to communicate with the proxy: %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100104 strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000105
Damien Miller95def091999-11-25 00:26:21 +1100106 debug("Executing proxy command: %.500s", command_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000107
Damien Miller95def091999-11-25 00:26:21 +1100108 /* Fork and execute the proxy command. */
109 if ((pid = fork()) == 0) {
110 char *argv[10];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000111
Damien Miller95def091999-11-25 00:26:21 +1100112 /* Child. Permanently give up superuser privileges. */
Ben Lindstromf9c48842002-06-11 16:37:51 +0000113 seteuid(original_real_uid);
114 setuid(original_real_uid);
Damien Miller95def091999-11-25 00:26:21 +1100115
116 /* Redirect stdin and stdout. */
117 close(pin[1]);
118 if (pin[0] != 0) {
119 if (dup2(pin[0], 0) < 0)
120 perror("dup2 stdin");
121 close(pin[0]);
122 }
123 close(pout[0]);
124 if (dup2(pout[1], 1) < 0)
125 perror("dup2 stdout");
126 /* Cannot be 1 because pin allocated two descriptors. */
127 close(pout[1]);
128
129 /* Stderr is left as it is so that error messages get
130 printed on the user's terminal. */
Damien Miller7b413d22000-07-01 13:24:21 +1000131 argv[0] = _PATH_BSHELL;
Damien Miller95def091999-11-25 00:26:21 +1100132 argv[1] = "-c";
133 argv[2] = command_string;
134 argv[3] = NULL;
135
136 /* Execute the proxy command. Note that we gave up any
137 extra privileges above. */
Kevin Stevesfcd5d602001-01-07 11:45:22 +0000138 execv(argv[0], argv);
139 perror(argv[0]);
Damien Miller95def091999-11-25 00:26:21 +1100140 exit(1);
141 }
142 /* Parent. */
143 if (pid < 0)
144 fatal("fork failed: %.100s", strerror(errno));
Damien Miller8c4e18a2002-09-19 12:05:02 +1000145 else
146 proxy_command_pid = pid; /* save pid to clean up later */
Damien Miller95def091999-11-25 00:26:21 +1100147
148 /* Close child side of the descriptors. */
149 close(pin[0]);
150 close(pout[1]);
151
152 /* Free the command name. */
153 buffer_free(&command);
154
155 /* Set the connection file descriptors. */
156 packet_set_connection(pout[0], pin[1]);
157
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000158 /* Indicate OK return */
159 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000160}
161
Damien Miller95def091999-11-25 00:26:21 +1100162/*
163 * Creates a (possibly privileged) socket for use as the ssh connection.
164 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000165static int
Ben Lindstromf9c48842002-06-11 16:37:51 +0000166ssh_create_socket(int privileged, int family)
Damien Miller95def091999-11-25 00:26:21 +1100167{
Ben Lindstrome0f88042001-04-30 13:06:24 +0000168 int sock, gaierr;
169 struct addrinfo hints, *res;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000170
Damien Miller5428f641999-11-25 11:54:57 +1100171 /*
172 * If we are running as root and want to connect to a privileged
173 * port, bind our own socket to a privileged port.
174 */
Damien Miller95def091999-11-25 00:26:21 +1100175 if (privileged) {
176 int p = IPPORT_RESERVED - 1;
Ben Lindstromf9c48842002-06-11 16:37:51 +0000177 PRIV_START;
Damien Miller34132e52000-01-14 15:45:46 +1100178 sock = rresvport_af(&p, family);
Ben Lindstromf9c48842002-06-11 16:37:51 +0000179 PRIV_END;
Damien Miller95def091999-11-25 00:26:21 +1100180 if (sock < 0)
Damien Miller98c7ad62000-03-09 21:27:49 +1100181 error("rresvport: af=%d %.100s", family, strerror(errno));
182 else
183 debug("Allocated local port %d.", p);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000184 return sock;
Damien Miller95def091999-11-25 00:26:21 +1100185 }
Ben Lindstrome0f88042001-04-30 13:06:24 +0000186 sock = socket(family, SOCK_STREAM, 0);
187 if (sock < 0)
188 error("socket: %.100s", strerror(errno));
Ben Lindstrome0f88042001-04-30 13:06:24 +0000189
190 /* Bind the socket to an alternative local IP address */
191 if (options.bind_address == NULL)
192 return sock;
193
194 memset(&hints, 0, sizeof(hints));
Damien Miller7ea6f202001-10-10 15:04:41 +1000195 hints.ai_family = family;
Ben Lindstrome0f88042001-04-30 13:06:24 +0000196 hints.ai_socktype = SOCK_STREAM;
197 hints.ai_flags = AI_PASSIVE;
198 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
199 if (gaierr) {
200 error("getaddrinfo: %s: %s", options.bind_address,
201 gai_strerror(gaierr));
202 close(sock);
203 return -1;
204 }
205 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
206 error("bind: %s: %s", options.bind_address, strerror(errno));
207 close(sock);
208 freeaddrinfo(res);
209 return -1;
210 }
211 freeaddrinfo(res);
Damien Miller95def091999-11-25 00:26:21 +1100212 return sock;
213}
214
215/*
Damien Miller34132e52000-01-14 15:45:46 +1100216 * Opens a TCP/IP connection to the remote server on the given host.
217 * The address of the remote host will be returned in hostaddr.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000218 * If port is 0, the default port will be used. If needpriv is true,
Damien Miller95def091999-11-25 00:26:21 +1100219 * a privileged port will be allocated to make the connection.
Ben Lindstromf9c48842002-06-11 16:37:51 +0000220 * This requires super-user privileges if needpriv is true.
Damien Miller95def091999-11-25 00:26:21 +1100221 * Connection_attempts specifies the maximum number of tries (one per
222 * second). If proxy_command is non-NULL, it specifies the command (with %h
223 * and %p substituted for host and port, respectively) to use to contact
224 * the daemon.
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000225 * Return values:
226 * 0 for OK
227 * ECONNREFUSED if we got a "Connection Refused" by the peer on any address
228 * ECONNABORTED if we failed without a "Connection refused"
229 * Suitable error messages for the connection failure will already have been
230 * printed.
Damien Miller95def091999-11-25 00:26:21 +1100231 */
232int
Damien Miller34132e52000-01-14 15:45:46 +1100233ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
Damien Miller139d4cd2001-10-10 15:07:44 +1000234 u_short port, int family, int connection_attempts,
Ben Lindstromf9c48842002-06-11 16:37:51 +0000235 int needpriv, const char *proxy_command)
Damien Miller95def091999-11-25 00:26:21 +1100236{
Damien Miller34132e52000-01-14 15:45:46 +1100237 int gaierr;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000238 int on = 1;
239 int sock = -1, attempt;
240 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
241 struct addrinfo hints, *ai, *aitop;
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;
Ben Lindstrom728aa7e2002-07-15 17:48:11 +0000310 debug("connect to address %s port %s: %s",
311 ntop, strport, strerror(errno));
Damien Miller5428f641999-11-25 11:54:57 +1100312 /*
313 * Close the failed socket; there appear to
314 * be some problems when reusing a socket for
315 * which connect() has already returned an
316 * error.
317 */
Damien Miller95def091999-11-25 00:26:21 +1100318 close(sock);
319 }
Damien Miller95def091999-11-25 00:26:21 +1100320 }
Damien Miller34132e52000-01-14 15:45:46 +1100321 if (ai)
322 break; /* Successful connection. */
Damien Miller95def091999-11-25 00:26:21 +1100323
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000324 attempt++;
325 if (attempt >= connection_attempts)
326 break;
Damien Miller95def091999-11-25 00:26:21 +1100327 /* Sleep a moment before retrying. */
328 sleep(1);
329 }
Damien Miller34132e52000-01-14 15:45:46 +1100330
331 freeaddrinfo(aitop);
332
Damien Miller95def091999-11-25 00:26:21 +1100333 /* Return failure if we didn't get a successful connection. */
Ben Lindstroma6cd75c2002-07-11 04:00:19 +0000334 if (attempt >= connection_attempts) {
335 log("ssh: connect to host %s port %s: %s",
336 host, strport, strerror(errno));
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000337 return full_failure ? ECONNABORTED : ECONNREFUSED;
Ben Lindstroma6cd75c2002-07-11 04:00:19 +0000338 }
Damien Miller95def091999-11-25 00:26:21 +1100339
340 debug("Connection established.");
341
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000342 /* Set keepalives if requested. */
343 if (options.keepalives &&
344 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
345 sizeof(on)) < 0)
346 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100347
348 /* Set the connection. */
349 packet_set_connection(sock, sock);
350
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000351 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100352}
353
Damien Milleraae6c611999-12-06 11:47:28 +1100354/*
Damien Miller95def091999-11-25 00:26:21 +1100355 * Waits for the server identification string, and sends our own
356 * identification string.
357 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000358static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000359ssh_exchange_identification(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000360{
Damien Miller95def091999-11-25 00:26:21 +1100361 char buf[256], remote_version[256]; /* must be same size! */
Damien Miller78928792000-04-12 20:17:38 +1000362 int remote_major, remote_minor, i, mismatch;
Damien Miller95def091999-11-25 00:26:21 +1100363 int connection_in = packet_get_connection_in();
364 int connection_out = packet_get_connection_out();
Kevin Stevesef4eea92001-02-05 12:42:17 +0000365 int minor1 = PROTOCOL_MINOR_1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000366
Damien Miller95def091999-11-25 00:26:21 +1100367 /* Read other side\'s version identification. */
Damien Millerf6d9e222000-06-18 14:50:44 +1000368 for (;;) {
369 for (i = 0; i < sizeof(buf) - 1; i++) {
370 int len = atomicio(read, connection_in, &buf[i], 1);
371 if (len < 0)
372 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
373 if (len != 1)
374 fatal("ssh_exchange_identification: Connection closed by remote host");
375 if (buf[i] == '\r') {
376 buf[i] = '\n';
377 buf[i + 1] = 0;
378 continue; /**XXX wait for \n */
379 }
380 if (buf[i] == '\n') {
381 buf[i + 1] = 0;
382 break;
383 }
Damien Miller95def091999-11-25 00:26:21 +1100384 }
Damien Millerf6d9e222000-06-18 14:50:44 +1000385 buf[sizeof(buf) - 1] = 0;
386 if (strncmp(buf, "SSH-", 4) == 0)
Damien Miller95def091999-11-25 00:26:21 +1100387 break;
Damien Millerf6d9e222000-06-18 14:50:44 +1000388 debug("ssh_exchange_identification: %s", buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000389 }
Damien Miller1383bd82000-04-06 12:32:37 +1000390 server_version_string = xstrdup(buf);
Damien Miller95def091999-11-25 00:26:21 +1100391
Damien Miller5428f641999-11-25 11:54:57 +1100392 /*
393 * Check that the versions match. In future this might accept
394 * several versions and set appropriate flags to handle them.
395 */
Damien Miller1383bd82000-04-06 12:32:37 +1000396 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
397 &remote_major, &remote_minor, remote_version) != 3)
Damien Miller95def091999-11-25 00:26:21 +1100398 fatal("Bad remote protocol version identification: '%.100s'", buf);
399 debug("Remote protocol version %d.%d, remote software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100400 remote_major, remote_minor, remote_version);
Damien Miller95def091999-11-25 00:26:21 +1100401
Damien Miller1383bd82000-04-06 12:32:37 +1000402 compat_datafellows(remote_version);
Damien Miller78928792000-04-12 20:17:38 +1000403 mismatch = 0;
Damien Miller1383bd82000-04-06 12:32:37 +1000404
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000405 switch (remote_major) {
Damien Miller78928792000-04-12 20:17:38 +1000406 case 1:
407 if (remote_minor == 99 &&
408 (options.protocol & SSH_PROTO_2) &&
409 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
410 enable_compat20();
411 break;
Damien Miller95def091999-11-25 00:26:21 +1100412 }
Damien Miller78928792000-04-12 20:17:38 +1000413 if (!(options.protocol & SSH_PROTO_1)) {
414 mismatch = 1;
415 break;
416 }
417 if (remote_minor < 3) {
418 fatal("Remote machine has too old SSH software version.");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100419 } else if (remote_minor == 3 || remote_minor == 4) {
Damien Miller78928792000-04-12 20:17:38 +1000420 /* We speak 1.3, too. */
421 enable_compat13();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100422 minor1 = 3;
Damien Miller78928792000-04-12 20:17:38 +1000423 if (options.forward_agent) {
424 log("Agent forwarding disabled for protocol 1.3");
425 options.forward_agent = 0;
426 }
427 }
428 break;
429 case 2:
430 if (options.protocol & SSH_PROTO_2) {
431 enable_compat20();
432 break;
433 }
434 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000435 default:
Damien Miller78928792000-04-12 20:17:38 +1000436 mismatch = 1;
437 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000438 }
Damien Miller78928792000-04-12 20:17:38 +1000439 if (mismatch)
Damien Miller95def091999-11-25 00:26:21 +1100440 fatal("Protocol major versions differ: %d vs. %d",
Damien Miller78928792000-04-12 20:17:38 +1000441 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
442 remote_major);
Damien Miller95def091999-11-25 00:26:21 +1100443 /* Send our own protocol version identification. */
444 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
Damien Miller78928792000-04-12 20:17:38 +1000445 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
Damien Miller0bc1bd82000-11-13 22:57:25 +1100446 compat20 ? PROTOCOL_MINOR_2 : minor1,
Damien Miller1383bd82000-04-06 12:32:37 +1000447 SSH_VERSION);
Damien Miller037a0dc1999-12-07 15:38:31 +1100448 if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
Damien Miller95def091999-11-25 00:26:21 +1100449 fatal("write: %.100s", strerror(errno));
Damien Miller1383bd82000-04-06 12:32:37 +1000450 client_version_string = xstrdup(buf);
451 chop(client_version_string);
452 chop(server_version_string);
453 debug("Local version string %.100s", client_version_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000454}
455
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000456/* defaults to 'no' */
Ben Lindstrombba81212001-06-25 05:01:22 +0000457static int
Damien Millere3980042001-10-10 15:02:03 +1000458confirm(const char *prompt)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000459{
Damien Miller49d795c2002-01-22 23:34:12 +1100460 const char *msg, *again = "Please type 'yes' or 'no': ";
461 char *p;
462 int ret = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000463
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000464 if (options.batch_mode)
465 return 0;
Damien Miller49d795c2002-01-22 23:34:12 +1100466 for (msg = prompt;;msg = again) {
467 p = read_passphrase(msg, RP_ECHO);
468 if (p == NULL ||
469 (p[0] == '\0') || (p[0] == '\n') ||
470 strncasecmp(p, "no", 2) == 0)
471 ret = 0;
Ben Lindstrom04f9af72002-07-04 00:03:56 +0000472 if (p && strncasecmp(p, "yes", 3) == 0)
Damien Miller49d795c2002-01-22 23:34:12 +1100473 ret = 1;
474 if (p)
475 xfree(p);
476 if (ret != -1)
477 return ret;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000478 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000479}
480
Damien Miller95def091999-11-25 00:26:21 +1100481/*
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000482 * check whether the supplied host key is valid, return -1 if the key
483 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
Damien Miller95def091999-11-25 00:26:21 +1100484 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000485static int
Damien Millereba71ba2000-04-29 23:57:08 +1000486check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000487 int readonly, const char *user_hostfile, const char *system_hostfile)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000488{
Damien Miller450a7a12000-03-26 13:04:51 +1000489 Key *file_key;
Damien Millere247cc42000-05-07 12:03:14 +1000490 char *type = key_type(host_key);
Damien Millera34a28b1999-12-14 10:47:15 +1100491 char *ip = NULL;
Ben Lindstromcfccef92001-03-13 04:57:58 +0000492 char hostline[1000], *hostp, *fp;
Damien Miller95def091999-11-25 00:26:21 +1100493 HostStatus host_status;
494 HostStatus ip_status;
Damien Miller34132e52000-01-14 15:45:46 +1100495 int local = 0, host_ip_differ = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100496 int salen;
Damien Miller34132e52000-01-14 15:45:46 +1100497 char ntop[NI_MAXHOST];
Damien Miller49d795c2002-01-22 23:34:12 +1100498 char msg[1024];
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000499 int len, host_line, ip_line, has_keys;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000500 const char *host_file = NULL, *ip_file = NULL;
Damien Miller34132e52000-01-14 15:45:46 +1100501
502 /*
503 * Force accepting of the host key for loopback/localhost. The
504 * problem is that if the home directory is NFS-mounted to multiple
505 * machines, localhost will refer to a different machine in each of
506 * them, and the user will get bogus HOST_CHANGED warnings. This
507 * essentially disables host authentication for localhost; however,
508 * this is probably not a real problem.
509 */
Damien Millereba71ba2000-04-29 23:57:08 +1000510 /** hostaddr == 0! */
Damien Miller34132e52000-01-14 15:45:46 +1100511 switch (hostaddr->sa_family) {
512 case AF_INET:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000513 local = (ntohl(((struct sockaddr_in *)hostaddr)->
Kevin Steves399ec972002-03-05 18:59:45 +0000514 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
Damien Millereaf99942000-01-19 13:45:07 +1100515 salen = sizeof(struct sockaddr_in);
Damien Miller34132e52000-01-14 15:45:46 +1100516 break;
517 case AF_INET6:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000518 local = IN6_IS_ADDR_LOOPBACK(
519 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
Damien Millereaf99942000-01-19 13:45:07 +1100520 salen = sizeof(struct sockaddr_in6);
Damien Miller34132e52000-01-14 15:45:46 +1100521 break;
522 default:
523 local = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100524 salen = sizeof(struct sockaddr_storage);
Damien Miller34132e52000-01-14 15:45:46 +1100525 break;
526 }
Ben Lindstrom3cecc9a2001-10-03 17:39:38 +0000527 if (options.no_host_authentication_for_localhost == 1 && local &&
528 options.host_key_alias == NULL) {
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000529 debug("Forcing accepting of host key for "
530 "loopback/localhost.");
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000531 return 0;
Damien Miller34132e52000-01-14 15:45:46 +1100532 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000533
Damien Milleraae6c611999-12-06 11:47:28 +1100534 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000535 * We don't have the remote ip-address for connections
536 * using a proxy command
Damien Milleraae6c611999-12-06 11:47:28 +1100537 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000538 if (options.proxy_command == NULL) {
539 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
540 NULL, 0, NI_NUMERICHOST) != 0)
541 fatal("check_host_key: getnameinfo failed");
542 ip = xstrdup(ntop);
543 } else {
544 ip = xstrdup("<no hostip for proxy command>");
545 }
546 /*
547 * Turn off check_host_ip if the connection is to localhost, via proxy
548 * command or if we don't have a hostname to compare with
549 */
550 if (options.check_host_ip &&
551 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
Damien Milleraae6c611999-12-06 11:47:28 +1100552 options.check_host_ip = 0;
553
Damien Millera34a28b1999-12-14 10:47:15 +1100554 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000555 * Allow the user to record the key under a different name. This is
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000556 * useful for ssh tunneling over forwarded connections or if you run
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000557 * multiple sshd's on different ports on the same machine.
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000558 */
559 if (options.host_key_alias != NULL) {
560 host = options.host_key_alias;
561 debug("using hostkeyalias: %s", host);
562 }
563
564 /*
Damien Millera34a28b1999-12-14 10:47:15 +1100565 * Store the host key from the known host file in here so that we can
566 * compare it with the key for the IP address.
567 */
Damien Miller450a7a12000-03-26 13:04:51 +1000568 file_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000569
Damien Miller5428f641999-11-25 11:54:57 +1100570 /*
571 * Check if the host key is present in the user\'s list of known
572 * hosts or in the systemwide list.
573 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000574 host_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000575 host_status = check_host_in_hostfile(host_file, host, host_key,
Damien Miller9f0f5c62001-12-21 14:45:46 +1100576 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000577 if (host_status == HOST_NEW) {
578 host_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000579 host_status = check_host_in_hostfile(host_file, host, host_key,
580 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000581 }
Damien Miller5428f641999-11-25 11:54:57 +1100582 /*
Damien Miller5428f641999-11-25 11:54:57 +1100583 * Also perform check for the ip address, skip the check if we are
584 * localhost or the hostname was an ip address to begin with
585 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000586 if (options.check_host_ip) {
Damien Miller450a7a12000-03-26 13:04:51 +1000587 Key *ip_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000588
Ben Lindstrom46c16222000-12-22 01:43:59 +0000589 ip_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000590 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
591 ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000592 if (ip_status == HOST_NEW) {
593 ip_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000594 ip_status = check_host_in_hostfile(ip_file, ip,
595 host_key, ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000596 }
Damien Miller95def091999-11-25 00:26:21 +1100597 if (host_status == HOST_CHANGED &&
Damien Miller450a7a12000-03-26 13:04:51 +1000598 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
Damien Miller95def091999-11-25 00:26:21 +1100599 host_ip_differ = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000600
Damien Miller450a7a12000-03-26 13:04:51 +1000601 key_free(ip_key);
Damien Miller95def091999-11-25 00:26:21 +1100602 } else
603 ip_status = host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000604
Damien Miller450a7a12000-03-26 13:04:51 +1000605 key_free(file_key);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000606
Damien Miller95def091999-11-25 00:26:21 +1100607 switch (host_status) {
608 case HOST_OK:
609 /* The host is known and the key matches. */
Damien Millere247cc42000-05-07 12:03:14 +1000610 debug("Host '%.200s' is known and matches the %s host key.",
611 host, type);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000612 debug("Found key in %s:%d", host_file, host_line);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000613 if (options.check_host_ip && ip_status == HOST_NEW) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000614 if (readonly)
615 log("%s host key for IP address "
616 "'%.128s' not in list of known hosts.",
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000617 type, ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000618 else if (!add_host_to_hostfile(user_hostfile, ip,
Damien Miller9f0f5c62001-12-21 14:45:46 +1100619 host_key))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000620 log("Failed to add the %s host key for IP "
621 "address '%.128s' to the list of known "
622 "hosts (%.30s).", type, ip, user_hostfile);
623 else
624 log("Warning: Permanently added the %s host "
625 "key for IP address '%.128s' to the list "
626 "of known hosts.", type, ip);
Damien Miller95def091999-11-25 00:26:21 +1100627 }
628 break;
629 case HOST_NEW:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000630 if (readonly)
631 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100632 /* The host is new. */
633 if (options.strict_host_key_checking == 1) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000634 /*
635 * User has requested strict host key checking. We
636 * will not add the host key automatically. The only
637 * alternative left is to abort.
638 */
639 error("No %s host key is known for %.200s and you "
640 "have requested strict checking.", type, host);
641 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100642 } else if (options.strict_host_key_checking == 2) {
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000643 has_keys = show_other_keys(host, host_key);
Damien Miller95def091999-11-25 00:26:21 +1100644 /* The default */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000645 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller49d795c2002-01-22 23:34:12 +1100646 snprintf(msg, sizeof(msg),
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000647 "The authenticity of host '%.200s (%s)' can't be "
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000648 "established%s\n"
Damien Millere247cc42000-05-07 12:03:14 +1000649 "%s key fingerprint is %s.\n"
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000650 "Are you sure you want to continue connecting "
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000651 "(yes/no)? ",
652 host, ip,
653 has_keys ? ",\nbut keys of different type are already "
654 "known for this host." : ".",
655 type, fp);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000656 xfree(fp);
Damien Miller49d795c2002-01-22 23:34:12 +1100657 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000658 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100659 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000660 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Miller95def091999-11-25 00:26:21 +1100661 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
662 hostp = hostline;
663 } else
664 hostp = host;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000665
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000666 /*
667 * If not in strict mode, add the key automatically to the
668 * local known_hosts file.
669 */
Damien Millereba71ba2000-04-29 23:57:08 +1000670 if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000671 log("Failed to add the host to the list of known "
672 "hosts (%.500s).", user_hostfile);
Damien Miller95def091999-11-25 00:26:21 +1100673 else
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000674 log("Warning: Permanently added '%.200s' (%s) to the "
675 "list of known hosts.", hostp, type);
Damien Miller95def091999-11-25 00:26:21 +1100676 break;
677 case HOST_CHANGED:
678 if (options.check_host_ip && host_ip_differ) {
679 char *msg;
680 if (ip_status == HOST_NEW)
681 msg = "is unknown";
682 else if (ip_status == HOST_OK)
683 msg = "is unchanged";
684 else
685 msg = "has a different value";
686 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
687 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
688 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millere247cc42000-05-07 12:03:14 +1000689 error("The %s host key for %s has changed,", type, host);
Damien Miller95def091999-11-25 00:26:21 +1100690 error("and the key for the according IP address %s", ip);
691 error("%s. This could either mean that", msg);
692 error("DNS SPOOFING is happening or the IP address for the host");
Ben Lindstrom46c16222000-12-22 01:43:59 +0000693 error("and its host key have changed at the same time.");
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000694 if (ip_status != HOST_NEW)
Ben Lindstrom46c16222000-12-22 01:43:59 +0000695 error("Offending key for IP in %s:%d", ip_file, ip_line);
Damien Miller95def091999-11-25 00:26:21 +1100696 }
697 /* The host key has changed. */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000698 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller95def091999-11-25 00:26:21 +1100699 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millerf039bad1999-12-21 20:57:20 +1100700 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
Damien Miller95def091999-11-25 00:26:21 +1100701 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
702 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
703 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
Damien Millere247cc42000-05-07 12:03:14 +1000704 error("It is also possible that the %s host key has just been changed.", type);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000705 error("The fingerprint for the %s key sent by the remote host is\n%s.",
Ben Lindstromcfccef92001-03-13 04:57:58 +0000706 type, fp);
Damien Miller95def091999-11-25 00:26:21 +1100707 error("Please contact your system administrator.");
708 error("Add correct host key in %.100s to get rid of this message.",
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000709 user_hostfile);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000710 error("Offending key in %s:%d", host_file, host_line);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000711 xfree(fp);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000712
Damien Miller5428f641999-11-25 11:54:57 +1100713 /*
714 * If strict host key checking is in use, the user will have
715 * to edit the key manually and we can only abort.
716 */
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000717 if (options.strict_host_key_checking) {
718 error("%s host key for %.200s has changed and you have "
719 "requested strict checking.", type, host);
720 goto fail;
721 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000722
Damien Miller5428f641999-11-25 11:54:57 +1100723 /*
724 * If strict host key checking has not been requested, allow
725 * the connection but without password authentication or
726 * agent forwarding.
727 */
Damien Miller95def091999-11-25 00:26:21 +1100728 if (options.password_authentication) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000729 error("Password authentication is disabled to avoid "
730 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100731 options.password_authentication = 0;
732 }
733 if (options.forward_agent) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000734 error("Agent forwarding is disabled to avoid "
735 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100736 options.forward_agent = 0;
737 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000738 if (options.forward_x11) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000739 error("X11 forwarding is disabled to avoid "
740 "man-in-the-middle attacks.");
Ben Lindstromc72745a2000-12-02 19:03:54 +0000741 options.forward_x11 = 0;
742 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000743 if (options.num_local_forwards > 0 ||
744 options.num_remote_forwards > 0) {
745 error("Port forwarding is disabled to avoid "
746 "man-in-the-middle attacks.");
747 options.num_local_forwards =
Damien Miller9f0f5c62001-12-21 14:45:46 +1100748 options.num_remote_forwards = 0;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000749 }
Damien Miller5428f641999-11-25 11:54:57 +1100750 /*
751 * XXX Should permit the user to change to use the new id.
752 * This could be done by converting the host key to an
753 * identifying sentence, tell that the host identifies itself
754 * by that sentence, and ask the user if he/she whishes to
755 * accept the authentication.
756 */
Damien Miller95def091999-11-25 00:26:21 +1100757 break;
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000758 case HOST_FOUND:
759 fatal("internal error");
760 break;
Damien Miller95def091999-11-25 00:26:21 +1100761 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000762
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000763 if (options.check_host_ip && host_status != HOST_CHANGED &&
764 ip_status == HOST_CHANGED) {
Damien Miller49d795c2002-01-22 23:34:12 +1100765 snprintf(msg, sizeof(msg),
766 "Warning: the %s host key for '%.200s' "
767 "differs from the key for the IP address '%.128s'"
768 "\nOffending key for IP in %s:%d",
769 type, host, ip, ip_file, ip_line);
770 if (host_status == HOST_OK) {
771 len = strlen(msg);
772 snprintf(msg + len, sizeof(msg) - len,
773 "\nMatching host key in %s:%d",
Ben Lindstromcb72e4f2002-06-21 00:41:51 +0000774 host_file, host_line);
Damien Miller49d795c2002-01-22 23:34:12 +1100775 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000776 if (options.strict_host_key_checking == 1) {
Damien Miller49d795c2002-01-22 23:34:12 +1100777 log(msg);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000778 error("Exiting, you have requested strict checking.");
779 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000780 } else if (options.strict_host_key_checking == 2) {
Damien Miller49d795c2002-01-22 23:34:12 +1100781 strlcat(msg, "\nAre you sure you want "
782 "to continue connecting (yes/no)? ", sizeof(msg));
783 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000784 goto fail;
Damien Miller49d795c2002-01-22 23:34:12 +1100785 } else {
786 log(msg);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000787 }
788 }
789
Ben Lindstromc72745a2000-12-02 19:03:54 +0000790 xfree(ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000791 return 0;
792
793fail:
794 xfree(ip);
795 return -1;
796}
797
798int
799verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
800{
801 struct stat st;
802
803 /* return ok if the key can be found in an old keyfile */
804 if (stat(options.system_hostfile2, &st) == 0 ||
805 stat(options.user_hostfile2, &st) == 0) {
806 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
807 options.user_hostfile2, options.system_hostfile2) == 0)
808 return 0;
809 }
810 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
811 options.user_hostfile, options.system_hostfile);
Damien Millera34a28b1999-12-14 10:47:15 +1100812}
Damien Miller037a0dc1999-12-07 15:38:31 +1100813
Damien Miller396691a2000-01-20 22:44:08 +1100814/*
815 * Starts a dialog with the server, and authenticates the current user on the
816 * server. This does not need any extra privileges. The basic connection
817 * to the server must already have been established before this is called.
818 * If login fails, this function prints an error and never returns.
819 * This function does not require super-user privileges.
820 */
821void
Ben Lindstrom1bad2562002-06-06 19:57:33 +0000822ssh_login(Sensitive *sensitive, const char *orighost,
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000823 struct sockaddr *hostaddr, struct passwd *pw)
Damien Miller396691a2000-01-20 22:44:08 +1100824{
825 char *host, *cp;
Damien Millereba71ba2000-04-29 23:57:08 +1000826 char *server_user, *local_user;
827
Damien Millereba71ba2000-04-29 23:57:08 +1000828 local_user = xstrdup(pw->pw_name);
829 server_user = options.user ? options.user : local_user;
Damien Miller396691a2000-01-20 22:44:08 +1100830
831 /* Convert the user-supplied hostname into all lowercase. */
832 host = xstrdup(orighost);
833 for (cp = host; *cp; cp++)
834 if (isupper(*cp))
835 *cp = tolower(*cp);
836
837 /* Exchange protocol version identification strings with the server. */
838 ssh_exchange_identification();
839
840 /* Put the connection into non-blocking mode. */
841 packet_set_nonblocking();
842
Damien Miller396691a2000-01-20 22:44:08 +1100843 /* key exchange */
Damien Miller396691a2000-01-20 22:44:08 +1100844 /* authenticate user */
Damien Miller1383bd82000-04-06 12:32:37 +1000845 if (compat20) {
846 ssh_kex2(host, hostaddr);
Ben Lindstrom1bad2562002-06-06 19:57:33 +0000847 ssh_userauth2(local_user, server_user, host, sensitive);
Damien Miller1383bd82000-04-06 12:32:37 +1000848 } else {
Damien Miller1383bd82000-04-06 12:32:37 +1000849 ssh_kex(host, hostaddr);
Ben Lindstrom1bad2562002-06-06 19:57:33 +0000850 ssh_userauth1(local_user, server_user, host, sensitive);
Damien Miller1383bd82000-04-06 12:32:37 +1000851 }
Damien Miller396691a2000-01-20 22:44:08 +1100852}
Damien Miller79438cc2001-02-16 12:34:57 +1100853
854void
855ssh_put_password(char *password)
856{
857 int size;
858 char *padded;
859
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000860 if (datafellows & SSH_BUG_PASSWORDPAD) {
Ben Lindstrom664408d2001-06-09 01:42:01 +0000861 packet_put_cstring(password);
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000862 return;
863 }
Damien Miller79438cc2001-02-16 12:34:57 +1100864 size = roundup(strlen(password) + 1, 32);
865 padded = xmalloc(size);
866 memset(padded, 0, size);
867 strlcpy(padded, password, size);
868 packet_put_string(padded, size);
869 memset(padded, 0, size);
870 xfree(padded);
871}
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000872
873static int
874show_key_from_file(const char *file, const char *host, int keytype)
875{
876 Key *found;
877 char *fp;
878 int line, ret;
879
880 found = key_new(keytype);
881 if ((ret = lookup_key_in_hostfile_by_type(file, host,
882 keytype, found, &line))) {
883 fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
884 log("WARNING: %s key found for host %s\n"
Ben Lindstrom4b99be82002-08-01 01:26:29 +0000885 "in %s:%d\n"
Ben Lindstrom3ed66402002-08-01 01:21:56 +0000886 "%s key fingerprint %s.",
887 key_type(found), host, file, line,
888 key_type(found), fp);
889 xfree(fp);
890 }
891 key_free(found);
892 return (ret);
893}
894
895/* print all known host keys for a given host, but skip keys of given type */
896static int
897show_other_keys(const char *host, Key *key)
898{
899 int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
900 int i, found = 0;
901
902 for (i = 0; type[i] != -1; i++) {
903 if (type[i] == key->type)
904 continue;
905 if (type[i] != KEY_RSA1 &&
906 show_key_from_file(options.user_hostfile2, host, type[i])) {
907 found = 1;
908 continue;
909 }
910 if (type[i] != KEY_RSA1 &&
911 show_key_from_file(options.system_hostfile2, host, type[i])) {
912 found = 1;
913 continue;
914 }
915 if (show_key_from_file(options.user_hostfile, host, type[i])) {
916 found = 1;
917 continue;
918 }
919 if (show_key_from_file(options.system_hostfile, host, type[i])) {
920 found = 1;
921 continue;
922 }
923 debug2("no key of type %d for host %s", type[i], host);
924 }
925 return (found);
926}