blob: 0ae100fed6f3a1e29cdcfe95d7c532566233ecf7 [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 Lindstromf9cedb92001-08-06 21:07:11 +000016RCSID("$OpenBSD: sshconnect.c,v 1.110 2001/07/25 14:35:18 markus 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 Millerd4a8b7e1999-10-27 13:42:43 +100034
Damien Millereba71ba2000-04-29 23:57:08 +100035char *client_version_string = NULL;
36char *server_version_string = NULL;
Damien Miller1383bd82000-04-06 12:32:37 +100037
Damien Milleraae6c611999-12-06 11:47:28 +110038extern Options options;
Damien Miller34132e52000-01-14 15:45:46 +110039extern char *__progname;
Damien Milleraae6c611999-12-06 11:47:28 +110040
Ben Lindstrom226cfa02001-01-22 05:34:40 +000041/* AF_UNSPEC or AF_INET or AF_INET6 */
42extern int IPv4or6;
43
Tim Ricee991e3c2001-08-07 15:29:07 -070044#ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
45#define INET6_ADDRSTRLEN 46
46#endif
47
Ben Lindstromf9cedb92001-08-06 21:07:11 +000048static const char *
49sockaddr_ntop(struct sockaddr *sa)
50{
51 void *addr;
52 static char addrbuf[INET6_ADDRSTRLEN];
53
54 switch (sa->sa_family) {
55 case AF_INET:
56 addr = &((struct sockaddr_in *)sa)->sin_addr;
57 break;
58 case AF_INET6:
59 addr = &((struct sockaddr_in6 *)sa)->sin6_addr;
60 break;
61 default:
62 /* This case should be protected against elsewhere */
63 abort();
64 }
65 inet_ntop(sa->sa_family, addr, addrbuf, sizeof(addrbuf));
66 return addrbuf;
67}
68
Damien Miller95def091999-11-25 00:26:21 +110069/*
70 * Connect to the given ssh server using a proxy command.
71 */
Ben Lindstrombba81212001-06-25 05:01:22 +000072static int
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +000073ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
Damien Millerd4a8b7e1999-10-27 13:42:43 +100074 const char *proxy_command)
75{
Damien Miller95def091999-11-25 00:26:21 +110076 Buffer command;
77 const char *cp;
78 char *command_string;
79 int pin[2], pout[2];
Damien Miller166fca82000-04-20 07:42:21 +100080 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +110081 char strport[NI_MAXSERV];
Damien Millerd4a8b7e1999-10-27 13:42:43 +100082
Damien Miller95def091999-11-25 00:26:21 +110083 /* Convert the port number into a string. */
Damien Miller34132e52000-01-14 15:45:46 +110084 snprintf(strport, sizeof strport, "%hu", port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100085
Damien Miller95def091999-11-25 00:26:21 +110086 /* Build the final command string in the buffer by making the
87 appropriate substitutions to the given proxy command. */
88 buffer_init(&command);
89 for (cp = proxy_command; *cp; cp++) {
90 if (cp[0] == '%' && cp[1] == '%') {
91 buffer_append(&command, "%", 1);
92 cp++;
93 continue;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100094 }
Damien Miller95def091999-11-25 00:26:21 +110095 if (cp[0] == '%' && cp[1] == 'h') {
96 buffer_append(&command, host, strlen(host));
97 cp++;
98 continue;
99 }
100 if (cp[0] == '%' && cp[1] == 'p') {
Damien Miller34132e52000-01-14 15:45:46 +1100101 buffer_append(&command, strport, strlen(strport));
Damien Miller95def091999-11-25 00:26:21 +1100102 cp++;
103 continue;
104 }
105 buffer_append(&command, cp, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000106 }
Damien Miller95def091999-11-25 00:26:21 +1100107 buffer_append(&command, "\0", 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000108
Damien Miller95def091999-11-25 00:26:21 +1100109 /* Get the final command string. */
110 command_string = buffer_ptr(&command);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000111
Damien Miller95def091999-11-25 00:26:21 +1100112 /* Create pipes for communicating with the proxy. */
113 if (pipe(pin) < 0 || pipe(pout) < 0)
114 fatal("Could not create pipes to communicate with the proxy: %.100s",
115 strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000116
Damien Miller95def091999-11-25 00:26:21 +1100117 debug("Executing proxy command: %.500s", command_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000118
Damien Miller95def091999-11-25 00:26:21 +1100119 /* Fork and execute the proxy command. */
120 if ((pid = fork()) == 0) {
121 char *argv[10];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000122
Damien Miller95def091999-11-25 00:26:21 +1100123 /* Child. Permanently give up superuser privileges. */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000124 permanently_set_uid(pw);
Damien Miller95def091999-11-25 00:26:21 +1100125
126 /* Redirect stdin and stdout. */
127 close(pin[1]);
128 if (pin[0] != 0) {
129 if (dup2(pin[0], 0) < 0)
130 perror("dup2 stdin");
131 close(pin[0]);
132 }
133 close(pout[0]);
134 if (dup2(pout[1], 1) < 0)
135 perror("dup2 stdout");
136 /* Cannot be 1 because pin allocated two descriptors. */
137 close(pout[1]);
138
139 /* Stderr is left as it is so that error messages get
140 printed on the user's terminal. */
Damien Miller7b413d22000-07-01 13:24:21 +1000141 argv[0] = _PATH_BSHELL;
Damien Miller95def091999-11-25 00:26:21 +1100142 argv[1] = "-c";
143 argv[2] = command_string;
144 argv[3] = NULL;
145
146 /* Execute the proxy command. Note that we gave up any
147 extra privileges above. */
Kevin Stevesfcd5d602001-01-07 11:45:22 +0000148 execv(argv[0], argv);
149 perror(argv[0]);
Damien Miller95def091999-11-25 00:26:21 +1100150 exit(1);
151 }
152 /* Parent. */
153 if (pid < 0)
154 fatal("fork failed: %.100s", strerror(errno));
155
156 /* Close child side of the descriptors. */
157 close(pin[0]);
158 close(pout[1]);
159
160 /* Free the command name. */
161 buffer_free(&command);
162
163 /* Set the connection file descriptors. */
164 packet_set_connection(pout[0], pin[1]);
165
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000166 /* Indicate OK return */
167 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000168}
169
Damien Miller95def091999-11-25 00:26:21 +1100170/*
171 * Creates a (possibly privileged) socket for use as the ssh connection.
172 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000173static int
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000174ssh_create_socket(struct passwd *pw, int privileged, int family)
Damien Miller95def091999-11-25 00:26:21 +1100175{
Ben Lindstrome0f88042001-04-30 13:06:24 +0000176 int sock, gaierr;
177 struct addrinfo hints, *res;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000178
Damien Miller5428f641999-11-25 11:54:57 +1100179 /*
180 * If we are running as root and want to connect to a privileged
181 * port, bind our own socket to a privileged port.
182 */
Damien Miller95def091999-11-25 00:26:21 +1100183 if (privileged) {
184 int p = IPPORT_RESERVED - 1;
Damien Miller34132e52000-01-14 15:45:46 +1100185 sock = rresvport_af(&p, family);
Damien Miller95def091999-11-25 00:26:21 +1100186 if (sock < 0)
Damien Miller98c7ad62000-03-09 21:27:49 +1100187 error("rresvport: af=%d %.100s", family, strerror(errno));
188 else
189 debug("Allocated local port %d.", p);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000190 return sock;
Damien Miller95def091999-11-25 00:26:21 +1100191 }
Ben Lindstrome0f88042001-04-30 13:06:24 +0000192 /*
193 * Just create an ordinary socket on arbitrary port. We use
194 * the user's uid to create the socket.
195 */
196 temporarily_use_uid(pw);
197 sock = socket(family, SOCK_STREAM, 0);
198 if (sock < 0)
199 error("socket: %.100s", strerror(errno));
200 restore_uid();
201
202 /* Bind the socket to an alternative local IP address */
203 if (options.bind_address == NULL)
204 return sock;
205
206 memset(&hints, 0, sizeof(hints));
207 hints.ai_family = IPv4or6;
208 hints.ai_socktype = SOCK_STREAM;
209 hints.ai_flags = AI_PASSIVE;
210 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
211 if (gaierr) {
212 error("getaddrinfo: %s: %s", options.bind_address,
213 gai_strerror(gaierr));
214 close(sock);
215 return -1;
216 }
217 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
218 error("bind: %s: %s", options.bind_address, strerror(errno));
219 close(sock);
220 freeaddrinfo(res);
221 return -1;
222 }
223 freeaddrinfo(res);
Damien Miller95def091999-11-25 00:26:21 +1100224 return sock;
225}
226
227/*
Damien Miller34132e52000-01-14 15:45:46 +1100228 * Opens a TCP/IP connection to the remote server on the given host.
229 * The address of the remote host will be returned in hostaddr.
230 * If port is 0, the default port will be used. If anonymous is zero,
Damien Miller95def091999-11-25 00:26:21 +1100231 * a privileged port will be allocated to make the connection.
232 * This requires super-user privileges if anonymous is false.
233 * Connection_attempts specifies the maximum number of tries (one per
234 * second). If proxy_command is non-NULL, it specifies the command (with %h
235 * and %p substituted for host and port, respectively) to use to contact
236 * the daemon.
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000237 * Return values:
238 * 0 for OK
239 * ECONNREFUSED if we got a "Connection Refused" by the peer on any address
240 * ECONNABORTED if we failed without a "Connection refused"
241 * Suitable error messages for the connection failure will already have been
242 * printed.
Damien Miller95def091999-11-25 00:26:21 +1100243 */
244int
Damien Miller34132e52000-01-14 15:45:46 +1100245ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
Damien Milleraae6c611999-12-06 11:47:28 +1100246 u_short port, int connection_attempts,
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000247 int anonymous, struct passwd *pw,
Damien Miller95def091999-11-25 00:26:21 +1100248 const char *proxy_command)
249{
Damien Miller34132e52000-01-14 15:45:46 +1100250 int gaierr;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000251 int on = 1;
252 int sock = -1, attempt;
253 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
254 struct addrinfo hints, *ai, *aitop;
Damien Miller95def091999-11-25 00:26:21 +1100255 struct linger linger;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000256 struct servent *sp;
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000257 /*
258 * Did we get only other errors than "Connection refused" (which
259 * should block fallback to rsh and similar), or did we get at least
260 * one "Connection refused"?
261 */
262 int full_failure = 1;
Damien Miller95def091999-11-25 00:26:21 +1100263
Damien Millercaf6dd62000-08-29 11:33:50 +1100264 debug("ssh_connect: getuid %u geteuid %u anon %d",
265 (u_int) getuid(), (u_int) geteuid(), anonymous);
Damien Miller95def091999-11-25 00:26:21 +1100266
267 /* Get default port if port has not been set. */
268 if (port == 0) {
269 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
270 if (sp)
271 port = ntohs(sp->s_port);
272 else
273 port = SSH_DEFAULT_PORT;
274 }
275 /* If a proxy command is given, connect using it. */
276 if (proxy_command != NULL)
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000277 return ssh_proxy_connect(host, port, pw, proxy_command);
Damien Miller95def091999-11-25 00:26:21 +1100278
279 /* No proxy command. */
280
Damien Miller34132e52000-01-14 15:45:46 +1100281 memset(&hints, 0, sizeof(hints));
282 hints.ai_family = IPv4or6;
283 hints.ai_socktype = SOCK_STREAM;
284 snprintf(strport, sizeof strport, "%d", port);
285 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
286 fatal("%s: %.100s: %s", __progname, host,
287 gai_strerror(gaierr));
Damien Miller95def091999-11-25 00:26:21 +1100288
Damien Millera34a28b1999-12-14 10:47:15 +1100289 /*
290 * Try to connect several times. On some machines, the first time
291 * will sometimes fail. In general socket code appears to behave
292 * quite magically on many machines.
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000293 */
294 for (attempt = 0; ;) {
Damien Miller95def091999-11-25 00:26:21 +1100295 if (attempt > 0)
296 debug("Trying again...");
297
Damien Miller34132e52000-01-14 15:45:46 +1100298 /* Loop through addresses for this host, and try each one in
Damien Miller4af51302000-04-16 11:18:38 +1000299 sequence until the connection succeeds. */
Damien Miller34132e52000-01-14 15:45:46 +1100300 for (ai = aitop; ai; ai = ai->ai_next) {
301 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
302 continue;
303 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
304 ntop, sizeof(ntop), strport, sizeof(strport),
305 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
306 error("ssh_connect: getnameinfo failed");
307 continue;
308 }
309 debug("Connecting to %.200s [%.100s] port %s.",
310 host, ntop, strport);
Damien Miller95def091999-11-25 00:26:21 +1100311
Damien Miller34132e52000-01-14 15:45:46 +1100312 /* Create a socket for connecting. */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000313 sock = ssh_create_socket(pw,
Damien Millerbac2d8a2000-09-05 16:13:06 +1100314#ifdef HAVE_CYGWIN
Damien Miller0bc1bd82000-11-13 22:57:25 +1100315 !anonymous,
Damien Millerbac2d8a2000-09-05 16:13:06 +1100316#else
Damien Miller0bc1bd82000-11-13 22:57:25 +1100317 !anonymous && geteuid() == 0,
Damien Millerbac2d8a2000-09-05 16:13:06 +1100318#endif
Damien Miller34132e52000-01-14 15:45:46 +1100319 ai->ai_family);
320 if (sock < 0)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000321 /* Any error is already output */
Damien Miller34132e52000-01-14 15:45:46 +1100322 continue;
Damien Miller95def091999-11-25 00:26:21 +1100323
Damien Miller34132e52000-01-14 15:45:46 +1100324 /* Connect to the host. We use the user's uid in the
325 * hope that it will help with tcp_wrappers showing
326 * the remote uid as root.
Damien Miller5428f641999-11-25 11:54:57 +1100327 */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000328 temporarily_use_uid(pw);
Damien Miller34132e52000-01-14 15:45:46 +1100329 if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
330 /* Successful connection. */
Ben Lindstroma3700052001-04-05 23:26:32 +0000331 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
Damien Miller95def091999-11-25 00:26:21 +1100332 restore_uid();
333 break;
Damien Miller34132e52000-01-14 15:45:46 +1100334 } else {
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000335 if (errno == ECONNREFUSED)
336 full_failure = 0;
337 log("ssh: connect to address %s port %s: %s",
338 sockaddr_ntop(ai->ai_addr), strport,
339 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100340 restore_uid();
Damien Miller5428f641999-11-25 11:54:57 +1100341 /*
342 * Close the failed socket; there appear to
343 * be some problems when reusing a socket for
344 * which connect() has already returned an
345 * error.
346 */
Damien Miller95def091999-11-25 00:26:21 +1100347 shutdown(sock, SHUT_RDWR);
348 close(sock);
349 }
Damien Miller95def091999-11-25 00:26:21 +1100350 }
Damien Miller34132e52000-01-14 15:45:46 +1100351 if (ai)
352 break; /* Successful connection. */
Damien Miller95def091999-11-25 00:26:21 +1100353
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000354 attempt++;
355 if (attempt >= connection_attempts)
356 break;
Damien Miller95def091999-11-25 00:26:21 +1100357 /* Sleep a moment before retrying. */
358 sleep(1);
359 }
Damien Miller34132e52000-01-14 15:45:46 +1100360
361 freeaddrinfo(aitop);
362
Damien Miller95def091999-11-25 00:26:21 +1100363 /* Return failure if we didn't get a successful connection. */
364 if (attempt >= connection_attempts)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000365 return full_failure ? ECONNABORTED : ECONNREFUSED;
Damien Miller95def091999-11-25 00:26:21 +1100366
367 debug("Connection established.");
368
Damien Miller5428f641999-11-25 11:54:57 +1100369 /*
370 * Set socket options. We would like the socket to disappear as soon
371 * as it has been closed for whatever reason.
372 */
373 /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
Damien Miller95def091999-11-25 00:26:21 +1100374 linger.l_onoff = 1;
375 linger.l_linger = 5;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000376 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
377
378 /* Set keepalives if requested. */
379 if (options.keepalives &&
380 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
381 sizeof(on)) < 0)
382 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100383
384 /* Set the connection. */
385 packet_set_connection(sock, sock);
386
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000387 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100388}
389
Damien Milleraae6c611999-12-06 11:47:28 +1100390/*
Damien Miller95def091999-11-25 00:26:21 +1100391 * Waits for the server identification string, and sends our own
392 * identification string.
393 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000394static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000395ssh_exchange_identification(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000396{
Damien Miller95def091999-11-25 00:26:21 +1100397 char buf[256], remote_version[256]; /* must be same size! */
Damien Miller78928792000-04-12 20:17:38 +1000398 int remote_major, remote_minor, i, mismatch;
Damien Miller95def091999-11-25 00:26:21 +1100399 int connection_in = packet_get_connection_in();
400 int connection_out = packet_get_connection_out();
Kevin Stevesef4eea92001-02-05 12:42:17 +0000401 int minor1 = PROTOCOL_MINOR_1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000402
Damien Miller95def091999-11-25 00:26:21 +1100403 /* Read other side\'s version identification. */
Damien Millerf6d9e222000-06-18 14:50:44 +1000404 for (;;) {
405 for (i = 0; i < sizeof(buf) - 1; i++) {
406 int len = atomicio(read, connection_in, &buf[i], 1);
407 if (len < 0)
408 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
409 if (len != 1)
410 fatal("ssh_exchange_identification: Connection closed by remote host");
411 if (buf[i] == '\r') {
412 buf[i] = '\n';
413 buf[i + 1] = 0;
414 continue; /**XXX wait for \n */
415 }
416 if (buf[i] == '\n') {
417 buf[i + 1] = 0;
418 break;
419 }
Damien Miller95def091999-11-25 00:26:21 +1100420 }
Damien Millerf6d9e222000-06-18 14:50:44 +1000421 buf[sizeof(buf) - 1] = 0;
422 if (strncmp(buf, "SSH-", 4) == 0)
Damien Miller95def091999-11-25 00:26:21 +1100423 break;
Damien Millerf6d9e222000-06-18 14:50:44 +1000424 debug("ssh_exchange_identification: %s", buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000425 }
Damien Miller1383bd82000-04-06 12:32:37 +1000426 server_version_string = xstrdup(buf);
Damien Miller95def091999-11-25 00:26:21 +1100427
Damien Miller5428f641999-11-25 11:54:57 +1100428 /*
429 * Check that the versions match. In future this might accept
430 * several versions and set appropriate flags to handle them.
431 */
Damien Miller1383bd82000-04-06 12:32:37 +1000432 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
433 &remote_major, &remote_minor, remote_version) != 3)
Damien Miller95def091999-11-25 00:26:21 +1100434 fatal("Bad remote protocol version identification: '%.100s'", buf);
435 debug("Remote protocol version %d.%d, remote software version %.100s",
436 remote_major, remote_minor, remote_version);
437
Damien Miller1383bd82000-04-06 12:32:37 +1000438 compat_datafellows(remote_version);
Damien Miller78928792000-04-12 20:17:38 +1000439 mismatch = 0;
Damien Miller1383bd82000-04-06 12:32:37 +1000440
Damien Miller78928792000-04-12 20:17:38 +1000441 switch(remote_major) {
442 case 1:
443 if (remote_minor == 99 &&
444 (options.protocol & SSH_PROTO_2) &&
445 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
446 enable_compat20();
447 break;
Damien Miller95def091999-11-25 00:26:21 +1100448 }
Damien Miller78928792000-04-12 20:17:38 +1000449 if (!(options.protocol & SSH_PROTO_1)) {
450 mismatch = 1;
451 break;
452 }
453 if (remote_minor < 3) {
454 fatal("Remote machine has too old SSH software version.");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100455 } else if (remote_minor == 3 || remote_minor == 4) {
Damien Miller78928792000-04-12 20:17:38 +1000456 /* We speak 1.3, too. */
457 enable_compat13();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100458 minor1 = 3;
Damien Miller78928792000-04-12 20:17:38 +1000459 if (options.forward_agent) {
460 log("Agent forwarding disabled for protocol 1.3");
461 options.forward_agent = 0;
462 }
463 }
464 break;
465 case 2:
466 if (options.protocol & SSH_PROTO_2) {
467 enable_compat20();
468 break;
469 }
470 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000471 default:
Damien Miller78928792000-04-12 20:17:38 +1000472 mismatch = 1;
473 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000474 }
Damien Miller78928792000-04-12 20:17:38 +1000475 if (mismatch)
Damien Miller95def091999-11-25 00:26:21 +1100476 fatal("Protocol major versions differ: %d vs. %d",
Damien Miller78928792000-04-12 20:17:38 +1000477 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
478 remote_major);
Damien Miller95def091999-11-25 00:26:21 +1100479 /* Send our own protocol version identification. */
480 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
Damien Miller78928792000-04-12 20:17:38 +1000481 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
Damien Miller0bc1bd82000-11-13 22:57:25 +1100482 compat20 ? PROTOCOL_MINOR_2 : minor1,
Damien Miller1383bd82000-04-06 12:32:37 +1000483 SSH_VERSION);
Damien Miller037a0dc1999-12-07 15:38:31 +1100484 if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
Damien Miller95def091999-11-25 00:26:21 +1100485 fatal("write: %.100s", strerror(errno));
Damien Miller1383bd82000-04-06 12:32:37 +1000486 client_version_string = xstrdup(buf);
487 chop(client_version_string);
488 chop(server_version_string);
489 debug("Local version string %.100s", client_version_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000490}
491
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000492/* defaults to 'no' */
Ben Lindstrombba81212001-06-25 05:01:22 +0000493static int
Damien Miller95def091999-11-25 00:26:21 +1100494read_yes_or_no(const char *prompt, int defval)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000495{
Damien Miller95def091999-11-25 00:26:21 +1100496 char buf[1024];
497 FILE *f;
498 int retval = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000499
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000500 if (options.batch_mode)
501 return 0;
502
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000503 if (isatty(STDIN_FILENO))
Damien Miller95def091999-11-25 00:26:21 +1100504 f = stdin;
505 else
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000506 f = fopen(_PATH_TTY, "rw");
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000507
Damien Miller95def091999-11-25 00:26:21 +1100508 if (f == NULL)
509 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000510
Damien Miller95def091999-11-25 00:26:21 +1100511 fflush(stdout);
512
513 while (1) {
514 fprintf(stderr, "%s", prompt);
515 if (fgets(buf, sizeof(buf), f) == NULL) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000516 /*
517 * Print a newline (the prompt probably didn\'t have
518 * one).
519 */
Damien Miller95def091999-11-25 00:26:21 +1100520 fprintf(stderr, "\n");
521 strlcpy(buf, "no", sizeof buf);
522 }
523 /* Remove newline from response. */
524 if (strchr(buf, '\n'))
525 *strchr(buf, '\n') = 0;
526
527 if (buf[0] == 0)
528 retval = defval;
529 if (strcmp(buf, "yes") == 0)
530 retval = 1;
Damien Miller62cee002000-09-23 17:15:56 +1100531 else if (strcmp(buf, "no") == 0)
Damien Miller95def091999-11-25 00:26:21 +1100532 retval = 0;
Damien Miller62cee002000-09-23 17:15:56 +1100533 else
534 fprintf(stderr, "Please type 'yes' or 'no'.\n");
Damien Miller95def091999-11-25 00:26:21 +1100535
536 if (retval != -1) {
537 if (f != stdin)
538 fclose(f);
539 return retval;
540 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000541 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000542}
543
Damien Miller95def091999-11-25 00:26:21 +1100544/*
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000545 * check whether the supplied host key is valid, return -1 if the key
546 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
Damien Miller95def091999-11-25 00:26:21 +1100547 */
Damien Millera34a28b1999-12-14 10:47:15 +1100548
Ben Lindstrombba81212001-06-25 05:01:22 +0000549static int
Damien Millereba71ba2000-04-29 23:57:08 +1000550check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000551 int readonly, const char *user_hostfile, const char *system_hostfile)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000552{
Damien Miller450a7a12000-03-26 13:04:51 +1000553 Key *file_key;
Damien Millere247cc42000-05-07 12:03:14 +1000554 char *type = key_type(host_key);
Damien Millera34a28b1999-12-14 10:47:15 +1100555 char *ip = NULL;
Ben Lindstromcfccef92001-03-13 04:57:58 +0000556 char hostline[1000], *hostp, *fp;
Damien Miller95def091999-11-25 00:26:21 +1100557 HostStatus host_status;
558 HostStatus ip_status;
Damien Miller34132e52000-01-14 15:45:46 +1100559 int local = 0, host_ip_differ = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100560 int salen;
Damien Miller34132e52000-01-14 15:45:46 +1100561 char ntop[NI_MAXHOST];
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000562 int host_line, ip_line;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000563 const char *host_file = NULL, *ip_file = NULL;
Damien Miller34132e52000-01-14 15:45:46 +1100564
565 /*
566 * Force accepting of the host key for loopback/localhost. The
567 * problem is that if the home directory is NFS-mounted to multiple
568 * machines, localhost will refer to a different machine in each of
569 * them, and the user will get bogus HOST_CHANGED warnings. This
570 * essentially disables host authentication for localhost; however,
571 * this is probably not a real problem.
572 */
Damien Millereba71ba2000-04-29 23:57:08 +1000573 /** hostaddr == 0! */
Damien Miller34132e52000-01-14 15:45:46 +1100574 switch (hostaddr->sa_family) {
575 case AF_INET:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000576 local = (ntohl(((struct sockaddr_in *)hostaddr)->
577 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
Damien Millereaf99942000-01-19 13:45:07 +1100578 salen = sizeof(struct sockaddr_in);
Damien Miller34132e52000-01-14 15:45:46 +1100579 break;
580 case AF_INET6:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000581 local = IN6_IS_ADDR_LOOPBACK(
582 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
Damien Millereaf99942000-01-19 13:45:07 +1100583 salen = sizeof(struct sockaddr_in6);
Damien Miller34132e52000-01-14 15:45:46 +1100584 break;
585 default:
586 local = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100587 salen = sizeof(struct sockaddr_storage);
Damien Miller34132e52000-01-14 15:45:46 +1100588 break;
589 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000590 if (local && options.host_key_alias == NULL) {
591 debug("Forcing accepting of host key for "
592 "loopback/localhost.");
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000593 return 0;
Damien Miller34132e52000-01-14 15:45:46 +1100594 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000595
Damien Milleraae6c611999-12-06 11:47:28 +1100596 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000597 * We don't have the remote ip-address for connections
598 * using a proxy command
Damien Milleraae6c611999-12-06 11:47:28 +1100599 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000600 if (options.proxy_command == NULL) {
601 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
602 NULL, 0, NI_NUMERICHOST) != 0)
603 fatal("check_host_key: getnameinfo failed");
604 ip = xstrdup(ntop);
605 } else {
606 ip = xstrdup("<no hostip for proxy command>");
607 }
608 /*
609 * Turn off check_host_ip if the connection is to localhost, via proxy
610 * command or if we don't have a hostname to compare with
611 */
612 if (options.check_host_ip &&
613 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
Damien Milleraae6c611999-12-06 11:47:28 +1100614 options.check_host_ip = 0;
615
Damien Millera34a28b1999-12-14 10:47:15 +1100616 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000617 * Allow the user to record the key under a different name. This is
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000618 * useful for ssh tunneling over forwarded connections or if you run
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000619 * multiple sshd's on different ports on the same machine.
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000620 */
621 if (options.host_key_alias != NULL) {
622 host = options.host_key_alias;
623 debug("using hostkeyalias: %s", host);
624 }
625
626 /*
Damien Millera34a28b1999-12-14 10:47:15 +1100627 * Store the host key from the known host file in here so that we can
628 * compare it with the key for the IP address.
629 */
Damien Miller450a7a12000-03-26 13:04:51 +1000630 file_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000631
Damien Miller5428f641999-11-25 11:54:57 +1100632 /*
633 * Check if the host key is present in the user\'s list of known
634 * hosts or in the systemwide list.
635 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000636 host_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000637 host_status = check_host_in_hostfile(host_file, host, host_key,
638 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000639 if (host_status == HOST_NEW) {
640 host_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000641 host_status = check_host_in_hostfile(host_file, host, host_key,
642 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000643 }
Damien Miller5428f641999-11-25 11:54:57 +1100644 /*
Damien Miller5428f641999-11-25 11:54:57 +1100645 * Also perform check for the ip address, skip the check if we are
646 * localhost or the hostname was an ip address to begin with
647 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000648 if (options.check_host_ip) {
Damien Miller450a7a12000-03-26 13:04:51 +1000649 Key *ip_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000650
Ben Lindstrom46c16222000-12-22 01:43:59 +0000651 ip_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000652 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
653 ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000654 if (ip_status == HOST_NEW) {
655 ip_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000656 ip_status = check_host_in_hostfile(ip_file, ip,
657 host_key, ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000658 }
Damien Miller95def091999-11-25 00:26:21 +1100659 if (host_status == HOST_CHANGED &&
Damien Miller450a7a12000-03-26 13:04:51 +1000660 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
Damien Miller95def091999-11-25 00:26:21 +1100661 host_ip_differ = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000662
Damien Miller450a7a12000-03-26 13:04:51 +1000663 key_free(ip_key);
Damien Miller95def091999-11-25 00:26:21 +1100664 } else
665 ip_status = host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000666
Damien Miller450a7a12000-03-26 13:04:51 +1000667 key_free(file_key);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000668
Damien Miller95def091999-11-25 00:26:21 +1100669 switch (host_status) {
670 case HOST_OK:
671 /* The host is known and the key matches. */
Damien Millere247cc42000-05-07 12:03:14 +1000672 debug("Host '%.200s' is known and matches the %s host key.",
673 host, type);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000674 debug("Found key in %s:%d", host_file, host_line);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000675 if (options.check_host_ip && ip_status == HOST_NEW) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000676 if (readonly)
677 log("%s host key for IP address "
678 "'%.128s' not in list of known hosts.",
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000679 type, ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000680 else if (!add_host_to_hostfile(user_hostfile, ip,
681 host_key))
682 log("Failed to add the %s host key for IP "
683 "address '%.128s' to the list of known "
684 "hosts (%.30s).", type, ip, user_hostfile);
685 else
686 log("Warning: Permanently added the %s host "
687 "key for IP address '%.128s' to the list "
688 "of known hosts.", type, ip);
Damien Miller95def091999-11-25 00:26:21 +1100689 }
690 break;
691 case HOST_NEW:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000692 if (readonly)
693 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100694 /* The host is new. */
695 if (options.strict_host_key_checking == 1) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000696 /*
697 * User has requested strict host key checking. We
698 * will not add the host key automatically. The only
699 * alternative left is to abort.
700 */
701 error("No %s host key is known for %.200s and you "
702 "have requested strict checking.", type, host);
703 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100704 } else if (options.strict_host_key_checking == 2) {
705 /* The default */
706 char prompt[1024];
Ben Lindstromcfccef92001-03-13 04:57:58 +0000707 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller95def091999-11-25 00:26:21 +1100708 snprintf(prompt, sizeof(prompt),
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000709 "The authenticity of host '%.200s (%s)' can't be "
710 "established.\n"
Damien Millere247cc42000-05-07 12:03:14 +1000711 "%s key fingerprint is %s.\n"
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000712 "Are you sure you want to continue connecting "
713 "(yes/no)? ", host, ip, type, fp);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000714 xfree(fp);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000715 if (!read_yes_or_no(prompt, -1)) {
716 log("Aborted by user!");
717 goto fail;
718 }
Damien Miller95def091999-11-25 00:26:21 +1100719 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000720 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Miller95def091999-11-25 00:26:21 +1100721 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
722 hostp = hostline;
723 } else
724 hostp = host;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000725
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000726 /*
727 * If not in strict mode, add the key automatically to the
728 * local known_hosts file.
729 */
Damien Millereba71ba2000-04-29 23:57:08 +1000730 if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000731 log("Failed to add the host to the list of known "
732 "hosts (%.500s).", user_hostfile);
Damien Miller95def091999-11-25 00:26:21 +1100733 else
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000734 log("Warning: Permanently added '%.200s' (%s) to the "
735 "list of known hosts.", hostp, type);
Damien Miller95def091999-11-25 00:26:21 +1100736 break;
737 case HOST_CHANGED:
738 if (options.check_host_ip && host_ip_differ) {
739 char *msg;
740 if (ip_status == HOST_NEW)
741 msg = "is unknown";
742 else if (ip_status == HOST_OK)
743 msg = "is unchanged";
744 else
745 msg = "has a different value";
746 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
747 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
748 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millere247cc42000-05-07 12:03:14 +1000749 error("The %s host key for %s has changed,", type, host);
Damien Miller95def091999-11-25 00:26:21 +1100750 error("and the key for the according IP address %s", ip);
751 error("%s. This could either mean that", msg);
752 error("DNS SPOOFING is happening or the IP address for the host");
Ben Lindstrom46c16222000-12-22 01:43:59 +0000753 error("and its host key have changed at the same time.");
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000754 if (ip_status != HOST_NEW)
Ben Lindstrom46c16222000-12-22 01:43:59 +0000755 error("Offending key for IP in %s:%d", ip_file, ip_line);
Damien Miller95def091999-11-25 00:26:21 +1100756 }
757 /* The host key has changed. */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000758 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller95def091999-11-25 00:26:21 +1100759 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millerf039bad1999-12-21 20:57:20 +1100760 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
Damien Miller95def091999-11-25 00:26:21 +1100761 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
762 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
763 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
Damien Millere247cc42000-05-07 12:03:14 +1000764 error("It is also possible that the %s host key has just been changed.", type);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000765 error("The fingerprint for the %s key sent by the remote host is\n%s.",
Ben Lindstromcfccef92001-03-13 04:57:58 +0000766 type, fp);
Damien Miller95def091999-11-25 00:26:21 +1100767 error("Please contact your system administrator.");
768 error("Add correct host key in %.100s to get rid of this message.",
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000769 user_hostfile);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000770 error("Offending key in %s:%d", host_file, host_line);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000771 xfree(fp);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000772
Damien Miller5428f641999-11-25 11:54:57 +1100773 /*
774 * If strict host key checking is in use, the user will have
775 * to edit the key manually and we can only abort.
776 */
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000777 if (options.strict_host_key_checking) {
778 error("%s host key for %.200s has changed and you have "
779 "requested strict checking.", type, host);
780 goto fail;
781 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000782
Damien Miller5428f641999-11-25 11:54:57 +1100783 /*
784 * If strict host key checking has not been requested, allow
785 * the connection but without password authentication or
786 * agent forwarding.
787 */
Damien Miller95def091999-11-25 00:26:21 +1100788 if (options.password_authentication) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000789 error("Password authentication is disabled to avoid "
790 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100791 options.password_authentication = 0;
792 }
793 if (options.forward_agent) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000794 error("Agent forwarding is disabled to avoid "
795 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100796 options.forward_agent = 0;
797 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000798 if (options.forward_x11) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000799 error("X11 forwarding is disabled to avoid "
800 "man-in-the-middle attacks.");
Ben Lindstromc72745a2000-12-02 19:03:54 +0000801 options.forward_x11 = 0;
802 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000803 if (options.num_local_forwards > 0 ||
804 options.num_remote_forwards > 0) {
805 error("Port forwarding is disabled to avoid "
806 "man-in-the-middle attacks.");
807 options.num_local_forwards =
808 options.num_remote_forwards = 0;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000809 }
Damien Miller5428f641999-11-25 11:54:57 +1100810 /*
811 * XXX Should permit the user to change to use the new id.
812 * This could be done by converting the host key to an
813 * identifying sentence, tell that the host identifies itself
814 * by that sentence, and ask the user if he/she whishes to
815 * accept the authentication.
816 */
Damien Miller95def091999-11-25 00:26:21 +1100817 break;
818 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000819
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000820 if (options.check_host_ip && host_status != HOST_CHANGED &&
821 ip_status == HOST_CHANGED) {
822 log("Warning: the %s host key for '%.200s' "
Kevin Steves43276862001-02-11 13:56:43 +0000823 "differs from the key for the IP address '%.128s'",
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000824 type, host, ip);
825 if (host_status == HOST_OK)
826 log("Matching host key in %s:%d", host_file, host_line);
827 log("Offending key for IP in %s:%d", ip_file, ip_line);
828 if (options.strict_host_key_checking == 1) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000829 error("Exiting, you have requested strict checking.");
830 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000831 } else if (options.strict_host_key_checking == 2) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000832 if (!read_yes_or_no("Are you sure you want "
833 "to continue connecting (yes/no)? ", -1)) {
834 log("Aborted by user!");
835 goto fail;
836 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000837 }
838 }
839
Ben Lindstromc72745a2000-12-02 19:03:54 +0000840 xfree(ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000841 return 0;
842
843fail:
844 xfree(ip);
845 return -1;
846}
847
848int
849verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
850{
851 struct stat st;
852
853 /* return ok if the key can be found in an old keyfile */
854 if (stat(options.system_hostfile2, &st) == 0 ||
855 stat(options.user_hostfile2, &st) == 0) {
856 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
857 options.user_hostfile2, options.system_hostfile2) == 0)
858 return 0;
859 }
860 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
861 options.user_hostfile, options.system_hostfile);
Damien Millera34a28b1999-12-14 10:47:15 +1100862}
Damien Miller037a0dc1999-12-07 15:38:31 +1100863
Damien Miller396691a2000-01-20 22:44:08 +1100864/*
865 * Starts a dialog with the server, and authenticates the current user on the
866 * server. This does not need any extra privileges. The basic connection
867 * to the server must already have been established before this is called.
868 * If login fails, this function prints an error and never returns.
869 * This function does not require super-user privileges.
870 */
871void
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000872ssh_login(Key **keys, int nkeys, const char *orighost,
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000873 struct sockaddr *hostaddr, struct passwd *pw)
Damien Miller396691a2000-01-20 22:44:08 +1100874{
875 char *host, *cp;
Damien Millereba71ba2000-04-29 23:57:08 +1000876 char *server_user, *local_user;
877
Damien Millereba71ba2000-04-29 23:57:08 +1000878 local_user = xstrdup(pw->pw_name);
879 server_user = options.user ? options.user : local_user;
Damien Miller396691a2000-01-20 22:44:08 +1100880
881 /* Convert the user-supplied hostname into all lowercase. */
882 host = xstrdup(orighost);
883 for (cp = host; *cp; cp++)
884 if (isupper(*cp))
885 *cp = tolower(*cp);
886
887 /* Exchange protocol version identification strings with the server. */
888 ssh_exchange_identification();
889
890 /* Put the connection into non-blocking mode. */
891 packet_set_nonblocking();
892
Damien Miller396691a2000-01-20 22:44:08 +1100893 /* key exchange */
Damien Miller396691a2000-01-20 22:44:08 +1100894 /* authenticate user */
Damien Miller1383bd82000-04-06 12:32:37 +1000895 if (compat20) {
896 ssh_kex2(host, hostaddr);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000897 ssh_userauth2(local_user, server_user, host, keys, nkeys);
Damien Miller1383bd82000-04-06 12:32:37 +1000898 } else {
Damien Miller1383bd82000-04-06 12:32:37 +1000899 ssh_kex(host, hostaddr);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000900 ssh_userauth1(local_user, server_user, host, keys, nkeys);
Damien Miller1383bd82000-04-06 12:32:37 +1000901 }
Damien Miller396691a2000-01-20 22:44:08 +1100902}
Damien Miller79438cc2001-02-16 12:34:57 +1100903
904void
905ssh_put_password(char *password)
906{
907 int size;
908 char *padded;
909
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000910 if (datafellows & SSH_BUG_PASSWORDPAD) {
Ben Lindstrom664408d2001-06-09 01:42:01 +0000911 packet_put_cstring(password);
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000912 return;
913 }
Damien Miller79438cc2001-02-16 12:34:57 +1100914 size = roundup(strlen(password) + 1, 32);
915 padded = xmalloc(size);
916 memset(padded, 0, size);
917 strlcpy(padded, password, size);
918 packet_put_string(padded, size);
919 memset(padded, 0, size);
920 xfree(padded);
921}