blob: 511fe8f39fc385ff47bcfd967e7dd4231b84791e [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 Miller49d795c2002-01-22 23:34:12 +110016RCSID("$OpenBSD: sshconnect.c,v 1.119 2002/01/21 15:13:51 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 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
Damien Milleraae6c611999-12-06 11:47:28 +110039extern Options options;
Damien Miller34132e52000-01-14 15:45:46 +110040extern char *__progname;
Damien Milleraae6c611999-12-06 11:47:28 +110041
Tim Ricee991e3c2001-08-07 15:29:07 -070042#ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
43#define INET6_ADDRSTRLEN 46
44#endif
45
Ben Lindstromf9cedb92001-08-06 21:07:11 +000046static const char *
47sockaddr_ntop(struct sockaddr *sa)
48{
49 void *addr;
50 static char addrbuf[INET6_ADDRSTRLEN];
51
52 switch (sa->sa_family) {
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +000053 case AF_INET:
54 addr = &((struct sockaddr_in *)sa)->sin_addr;
55 break;
56 case AF_INET6:
57 addr = &((struct sockaddr_in6 *)sa)->sin6_addr;
58 break;
59 default:
60 /* This case should be protected against elsewhere */
61 abort(); /* XXX abort is bad -- do something else */
Ben Lindstromf9cedb92001-08-06 21:07:11 +000062 }
63 inet_ntop(sa->sa_family, addr, addrbuf, sizeof(addrbuf));
64 return addrbuf;
65}
66
Damien Miller95def091999-11-25 00:26:21 +110067/*
68 * Connect to the given ssh server using a proxy command.
69 */
Ben Lindstrombba81212001-06-25 05:01:22 +000070static int
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +000071ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
Damien Millerd4a8b7e1999-10-27 13:42:43 +100072 const char *proxy_command)
73{
Damien Miller95def091999-11-25 00:26:21 +110074 Buffer command;
75 const char *cp;
76 char *command_string;
77 int pin[2], pout[2];
Damien Miller166fca82000-04-20 07:42:21 +100078 pid_t pid;
Damien Miller34132e52000-01-14 15:45:46 +110079 char strport[NI_MAXSERV];
Damien Millerd4a8b7e1999-10-27 13:42:43 +100080
Damien Miller95def091999-11-25 00:26:21 +110081 /* Convert the port number into a string. */
Damien Miller34132e52000-01-14 15:45:46 +110082 snprintf(strport, sizeof strport, "%hu", port);
Damien Millerd4a8b7e1999-10-27 13:42:43 +100083
Damien Miller95def091999-11-25 00:26:21 +110084 /* Build the final command string in the buffer by making the
85 appropriate substitutions to the given proxy command. */
86 buffer_init(&command);
87 for (cp = proxy_command; *cp; cp++) {
88 if (cp[0] == '%' && cp[1] == '%') {
89 buffer_append(&command, "%", 1);
90 cp++;
91 continue;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100092 }
Damien Miller95def091999-11-25 00:26:21 +110093 if (cp[0] == '%' && cp[1] == 'h') {
94 buffer_append(&command, host, strlen(host));
95 cp++;
96 continue;
97 }
98 if (cp[0] == '%' && cp[1] == 'p') {
Damien Miller34132e52000-01-14 15:45:46 +110099 buffer_append(&command, strport, strlen(strport));
Damien Miller95def091999-11-25 00:26:21 +1100100 cp++;
101 continue;
102 }
103 buffer_append(&command, cp, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000104 }
Damien Miller95def091999-11-25 00:26:21 +1100105 buffer_append(&command, "\0", 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000106
Damien Miller95def091999-11-25 00:26:21 +1100107 /* Get the final command string. */
108 command_string = buffer_ptr(&command);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000109
Damien Miller95def091999-11-25 00:26:21 +1100110 /* Create pipes for communicating with the proxy. */
111 if (pipe(pin) < 0 || pipe(pout) < 0)
112 fatal("Could not create pipes to communicate with the proxy: %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100113 strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000114
Damien Miller95def091999-11-25 00:26:21 +1100115 debug("Executing proxy command: %.500s", command_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000116
Damien Miller95def091999-11-25 00:26:21 +1100117 /* Fork and execute the proxy command. */
118 if ((pid = fork()) == 0) {
119 char *argv[10];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000120
Damien Miller95def091999-11-25 00:26:21 +1100121 /* Child. Permanently give up superuser privileges. */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000122 permanently_set_uid(pw);
Damien Miller95def091999-11-25 00:26:21 +1100123
124 /* Redirect stdin and stdout. */
125 close(pin[1]);
126 if (pin[0] != 0) {
127 if (dup2(pin[0], 0) < 0)
128 perror("dup2 stdin");
129 close(pin[0]);
130 }
131 close(pout[0]);
132 if (dup2(pout[1], 1) < 0)
133 perror("dup2 stdout");
134 /* Cannot be 1 because pin allocated two descriptors. */
135 close(pout[1]);
136
137 /* Stderr is left as it is so that error messages get
138 printed on the user's terminal. */
Damien Miller7b413d22000-07-01 13:24:21 +1000139 argv[0] = _PATH_BSHELL;
Damien Miller95def091999-11-25 00:26:21 +1100140 argv[1] = "-c";
141 argv[2] = command_string;
142 argv[3] = NULL;
143
144 /* Execute the proxy command. Note that we gave up any
145 extra privileges above. */
Kevin Stevesfcd5d602001-01-07 11:45:22 +0000146 execv(argv[0], argv);
147 perror(argv[0]);
Damien Miller95def091999-11-25 00:26:21 +1100148 exit(1);
149 }
150 /* Parent. */
151 if (pid < 0)
152 fatal("fork failed: %.100s", strerror(errno));
153
154 /* Close child side of the descriptors. */
155 close(pin[0]);
156 close(pout[1]);
157
158 /* Free the command name. */
159 buffer_free(&command);
160
161 /* Set the connection file descriptors. */
162 packet_set_connection(pout[0], pin[1]);
163
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000164 /* Indicate OK return */
165 return 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000166}
167
Damien Miller95def091999-11-25 00:26:21 +1100168/*
169 * Creates a (possibly privileged) socket for use as the ssh connection.
170 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000171static int
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000172ssh_create_socket(struct passwd *pw, int privileged, int family)
Damien Miller95def091999-11-25 00:26:21 +1100173{
Ben Lindstrome0f88042001-04-30 13:06:24 +0000174 int sock, gaierr;
175 struct addrinfo hints, *res;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000176
Damien Miller5428f641999-11-25 11:54:57 +1100177 /*
178 * If we are running as root and want to connect to a privileged
179 * port, bind our own socket to a privileged port.
180 */
Damien Miller95def091999-11-25 00:26:21 +1100181 if (privileged) {
182 int p = IPPORT_RESERVED - 1;
Damien Miller34132e52000-01-14 15:45:46 +1100183 sock = rresvport_af(&p, family);
Damien Miller95def091999-11-25 00:26:21 +1100184 if (sock < 0)
Damien Miller98c7ad62000-03-09 21:27:49 +1100185 error("rresvport: af=%d %.100s", family, strerror(errno));
186 else
187 debug("Allocated local port %d.", p);
Ben Lindstrome0f88042001-04-30 13:06:24 +0000188 return sock;
Damien Miller95def091999-11-25 00:26:21 +1100189 }
Ben Lindstrome0f88042001-04-30 13:06:24 +0000190 /*
191 * Just create an ordinary socket on arbitrary port. We use
192 * the user's uid to create the socket.
193 */
194 temporarily_use_uid(pw);
195 sock = socket(family, SOCK_STREAM, 0);
196 if (sock < 0)
197 error("socket: %.100s", strerror(errno));
198 restore_uid();
199
200 /* Bind the socket to an alternative local IP address */
201 if (options.bind_address == NULL)
202 return sock;
203
204 memset(&hints, 0, sizeof(hints));
Damien Miller7ea6f202001-10-10 15:04:41 +1000205 hints.ai_family = family;
Ben Lindstrome0f88042001-04-30 13:06:24 +0000206 hints.ai_socktype = SOCK_STREAM;
207 hints.ai_flags = AI_PASSIVE;
208 gaierr = getaddrinfo(options.bind_address, "0", &hints, &res);
209 if (gaierr) {
210 error("getaddrinfo: %s: %s", options.bind_address,
211 gai_strerror(gaierr));
212 close(sock);
213 return -1;
214 }
215 if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
216 error("bind: %s: %s", options.bind_address, strerror(errno));
217 close(sock);
218 freeaddrinfo(res);
219 return -1;
220 }
221 freeaddrinfo(res);
Damien Miller95def091999-11-25 00:26:21 +1100222 return sock;
223}
224
225/*
Damien Miller34132e52000-01-14 15:45:46 +1100226 * Opens a TCP/IP connection to the remote server on the given host.
227 * The address of the remote host will be returned in hostaddr.
228 * If port is 0, the default port will be used. If anonymous is zero,
Damien Miller95def091999-11-25 00:26:21 +1100229 * a privileged port will be allocated to make the connection.
230 * This requires super-user privileges if anonymous is false.
231 * Connection_attempts specifies the maximum number of tries (one per
232 * second). If proxy_command is non-NULL, it specifies the command (with %h
233 * and %p substituted for host and port, respectively) to use to contact
234 * the daemon.
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000235 * Return values:
236 * 0 for OK
237 * ECONNREFUSED if we got a "Connection Refused" by the peer on any address
238 * ECONNABORTED if we failed without a "Connection refused"
239 * Suitable error messages for the connection failure will already have been
240 * printed.
Damien Miller95def091999-11-25 00:26:21 +1100241 */
242int
Damien Miller34132e52000-01-14 15:45:46 +1100243ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
Damien Miller139d4cd2001-10-10 15:07:44 +1000244 u_short port, int family, int connection_attempts,
245 int anonymous, struct passwd *pw, const char *proxy_command)
Damien Miller95def091999-11-25 00:26:21 +1100246{
Damien Miller34132e52000-01-14 15:45:46 +1100247 int gaierr;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000248 int on = 1;
249 int sock = -1, attempt;
250 char ntop[NI_MAXHOST], strport[NI_MAXSERV];
251 struct addrinfo hints, *ai, *aitop;
Damien Miller95def091999-11-25 00:26:21 +1100252 struct linger linger;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000253 struct servent *sp;
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000254 /*
255 * Did we get only other errors than "Connection refused" (which
256 * should block fallback to rsh and similar), or did we get at least
257 * one "Connection refused"?
258 */
259 int full_failure = 1;
Damien Miller95def091999-11-25 00:26:21 +1100260
Damien Millercaf6dd62000-08-29 11:33:50 +1100261 debug("ssh_connect: getuid %u geteuid %u anon %d",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100262 (u_int) getuid(), (u_int) geteuid(), anonymous);
Damien Miller95def091999-11-25 00:26:21 +1100263
264 /* Get default port if port has not been set. */
265 if (port == 0) {
266 sp = getservbyname(SSH_SERVICE_NAME, "tcp");
267 if (sp)
268 port = ntohs(sp->s_port);
269 else
270 port = SSH_DEFAULT_PORT;
271 }
272 /* If a proxy command is given, connect using it. */
273 if (proxy_command != NULL)
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000274 return ssh_proxy_connect(host, port, pw, proxy_command);
Damien Miller95def091999-11-25 00:26:21 +1100275
276 /* No proxy command. */
277
Damien Miller34132e52000-01-14 15:45:46 +1100278 memset(&hints, 0, sizeof(hints));
Damien Miller139d4cd2001-10-10 15:07:44 +1000279 hints.ai_family = family;
Damien Miller34132e52000-01-14 15:45:46 +1100280 hints.ai_socktype = SOCK_STREAM;
281 snprintf(strport, sizeof strport, "%d", port);
282 if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
283 fatal("%s: %.100s: %s", __progname, host,
284 gai_strerror(gaierr));
Damien Miller95def091999-11-25 00:26:21 +1100285
Damien Millera34a28b1999-12-14 10:47:15 +1100286 /*
287 * Try to connect several times. On some machines, the first time
288 * will sometimes fail. In general socket code appears to behave
289 * quite magically on many machines.
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000290 */
291 for (attempt = 0; ;) {
Damien Miller95def091999-11-25 00:26:21 +1100292 if (attempt > 0)
293 debug("Trying again...");
294
Damien Miller34132e52000-01-14 15:45:46 +1100295 /* Loop through addresses for this host, and try each one in
Damien Miller4af51302000-04-16 11:18:38 +1000296 sequence until the connection succeeds. */
Damien Miller34132e52000-01-14 15:45:46 +1100297 for (ai = aitop; ai; ai = ai->ai_next) {
298 if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
299 continue;
300 if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
301 ntop, sizeof(ntop), strport, sizeof(strport),
302 NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
303 error("ssh_connect: getnameinfo failed");
304 continue;
305 }
306 debug("Connecting to %.200s [%.100s] port %s.",
307 host, ntop, strport);
Damien Miller95def091999-11-25 00:26:21 +1100308
Damien Miller34132e52000-01-14 15:45:46 +1100309 /* Create a socket for connecting. */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000310 sock = ssh_create_socket(pw,
Damien Millerbac2d8a2000-09-05 16:13:06 +1100311#ifdef HAVE_CYGWIN
Damien Miller0bc1bd82000-11-13 22:57:25 +1100312 !anonymous,
Damien Millerbac2d8a2000-09-05 16:13:06 +1100313#else
Damien Miller0bc1bd82000-11-13 22:57:25 +1100314 !anonymous && geteuid() == 0,
Damien Millerbac2d8a2000-09-05 16:13:06 +1100315#endif
Damien Miller34132e52000-01-14 15:45:46 +1100316 ai->ai_family);
317 if (sock < 0)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000318 /* Any error is already output */
Damien Miller34132e52000-01-14 15:45:46 +1100319 continue;
Damien Miller95def091999-11-25 00:26:21 +1100320
Damien Miller34132e52000-01-14 15:45:46 +1100321 /* Connect to the host. We use the user's uid in the
322 * hope that it will help with tcp_wrappers showing
323 * the remote uid as root.
Damien Miller5428f641999-11-25 11:54:57 +1100324 */
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000325 temporarily_use_uid(pw);
Damien Miller34132e52000-01-14 15:45:46 +1100326 if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
327 /* Successful connection. */
Ben Lindstroma3700052001-04-05 23:26:32 +0000328 memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
Damien Miller95def091999-11-25 00:26:21 +1100329 restore_uid();
330 break;
Damien Miller34132e52000-01-14 15:45:46 +1100331 } else {
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000332 if (errno == ECONNREFUSED)
333 full_failure = 0;
334 log("ssh: connect to address %s port %s: %s",
335 sockaddr_ntop(ai->ai_addr), strport,
336 strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100337 restore_uid();
Damien Miller5428f641999-11-25 11:54:57 +1100338 /*
339 * Close the failed socket; there appear to
340 * be some problems when reusing a socket for
341 * which connect() has already returned an
342 * error.
343 */
Damien Miller95def091999-11-25 00:26:21 +1100344 close(sock);
345 }
Damien Miller95def091999-11-25 00:26:21 +1100346 }
Damien Miller34132e52000-01-14 15:45:46 +1100347 if (ai)
348 break; /* Successful connection. */
Damien Miller95def091999-11-25 00:26:21 +1100349
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000350 attempt++;
351 if (attempt >= connection_attempts)
352 break;
Damien Miller95def091999-11-25 00:26:21 +1100353 /* Sleep a moment before retrying. */
354 sleep(1);
355 }
Damien Miller34132e52000-01-14 15:45:46 +1100356
357 freeaddrinfo(aitop);
358
Damien Miller95def091999-11-25 00:26:21 +1100359 /* Return failure if we didn't get a successful connection. */
360 if (attempt >= connection_attempts)
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000361 return full_failure ? ECONNABORTED : ECONNREFUSED;
Damien Miller95def091999-11-25 00:26:21 +1100362
363 debug("Connection established.");
364
Damien Miller5428f641999-11-25 11:54:57 +1100365 /*
366 * Set socket options. We would like the socket to disappear as soon
367 * as it has been closed for whatever reason.
368 */
369 /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
Damien Miller95def091999-11-25 00:26:21 +1100370 linger.l_onoff = 1;
371 linger.l_linger = 5;
Ben Lindstrombf555ba2001-01-18 02:04:35 +0000372 setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger));
373
374 /* Set keepalives if requested. */
375 if (options.keepalives &&
376 setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
377 sizeof(on)) < 0)
378 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
Damien Miller95def091999-11-25 00:26:21 +1100379
380 /* Set the connection. */
381 packet_set_connection(sock, sock);
382
Ben Lindstromf9cedb92001-08-06 21:07:11 +0000383 return 0;
Damien Miller95def091999-11-25 00:26:21 +1100384}
385
Damien Milleraae6c611999-12-06 11:47:28 +1100386/*
Damien Miller95def091999-11-25 00:26:21 +1100387 * Waits for the server identification string, and sends our own
388 * identification string.
389 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000390static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000391ssh_exchange_identification(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000392{
Damien Miller95def091999-11-25 00:26:21 +1100393 char buf[256], remote_version[256]; /* must be same size! */
Damien Miller78928792000-04-12 20:17:38 +1000394 int remote_major, remote_minor, i, mismatch;
Damien Miller95def091999-11-25 00:26:21 +1100395 int connection_in = packet_get_connection_in();
396 int connection_out = packet_get_connection_out();
Kevin Stevesef4eea92001-02-05 12:42:17 +0000397 int minor1 = PROTOCOL_MINOR_1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000398
Damien Miller95def091999-11-25 00:26:21 +1100399 /* Read other side\'s version identification. */
Damien Millerf6d9e222000-06-18 14:50:44 +1000400 for (;;) {
401 for (i = 0; i < sizeof(buf) - 1; i++) {
402 int len = atomicio(read, connection_in, &buf[i], 1);
403 if (len < 0)
404 fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
405 if (len != 1)
406 fatal("ssh_exchange_identification: Connection closed by remote host");
407 if (buf[i] == '\r') {
408 buf[i] = '\n';
409 buf[i + 1] = 0;
410 continue; /**XXX wait for \n */
411 }
412 if (buf[i] == '\n') {
413 buf[i + 1] = 0;
414 break;
415 }
Damien Miller95def091999-11-25 00:26:21 +1100416 }
Damien Millerf6d9e222000-06-18 14:50:44 +1000417 buf[sizeof(buf) - 1] = 0;
418 if (strncmp(buf, "SSH-", 4) == 0)
Damien Miller95def091999-11-25 00:26:21 +1100419 break;
Damien Millerf6d9e222000-06-18 14:50:44 +1000420 debug("ssh_exchange_identification: %s", buf);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000421 }
Damien Miller1383bd82000-04-06 12:32:37 +1000422 server_version_string = xstrdup(buf);
Damien Miller95def091999-11-25 00:26:21 +1100423
Damien Miller5428f641999-11-25 11:54:57 +1100424 /*
425 * Check that the versions match. In future this might accept
426 * several versions and set appropriate flags to handle them.
427 */
Damien Miller1383bd82000-04-06 12:32:37 +1000428 if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
429 &remote_major, &remote_minor, remote_version) != 3)
Damien Miller95def091999-11-25 00:26:21 +1100430 fatal("Bad remote protocol version identification: '%.100s'", buf);
431 debug("Remote protocol version %d.%d, remote software version %.100s",
Damien Miller9f0f5c62001-12-21 14:45:46 +1100432 remote_major, remote_minor, remote_version);
Damien Miller95def091999-11-25 00:26:21 +1100433
Damien Miller1383bd82000-04-06 12:32:37 +1000434 compat_datafellows(remote_version);
Damien Miller78928792000-04-12 20:17:38 +1000435 mismatch = 0;
Damien Miller1383bd82000-04-06 12:32:37 +1000436
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000437 switch (remote_major) {
Damien Miller78928792000-04-12 20:17:38 +1000438 case 1:
439 if (remote_minor == 99 &&
440 (options.protocol & SSH_PROTO_2) &&
441 !(options.protocol & SSH_PROTO_1_PREFERRED)) {
442 enable_compat20();
443 break;
Damien Miller95def091999-11-25 00:26:21 +1100444 }
Damien Miller78928792000-04-12 20:17:38 +1000445 if (!(options.protocol & SSH_PROTO_1)) {
446 mismatch = 1;
447 break;
448 }
449 if (remote_minor < 3) {
450 fatal("Remote machine has too old SSH software version.");
Damien Miller0bc1bd82000-11-13 22:57:25 +1100451 } else if (remote_minor == 3 || remote_minor == 4) {
Damien Miller78928792000-04-12 20:17:38 +1000452 /* We speak 1.3, too. */
453 enable_compat13();
Damien Miller0bc1bd82000-11-13 22:57:25 +1100454 minor1 = 3;
Damien Miller78928792000-04-12 20:17:38 +1000455 if (options.forward_agent) {
456 log("Agent forwarding disabled for protocol 1.3");
457 options.forward_agent = 0;
458 }
459 }
460 break;
461 case 2:
462 if (options.protocol & SSH_PROTO_2) {
463 enable_compat20();
464 break;
465 }
466 /* FALLTHROUGH */
Damien Miller4af51302000-04-16 11:18:38 +1000467 default:
Damien Miller78928792000-04-12 20:17:38 +1000468 mismatch = 1;
469 break;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000470 }
Damien Miller78928792000-04-12 20:17:38 +1000471 if (mismatch)
Damien Miller95def091999-11-25 00:26:21 +1100472 fatal("Protocol major versions differ: %d vs. %d",
Damien Miller78928792000-04-12 20:17:38 +1000473 (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
474 remote_major);
Damien Miller95def091999-11-25 00:26:21 +1100475 /* Send our own protocol version identification. */
476 snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
Damien Miller78928792000-04-12 20:17:38 +1000477 compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
Damien Miller0bc1bd82000-11-13 22:57:25 +1100478 compat20 ? PROTOCOL_MINOR_2 : minor1,
Damien Miller1383bd82000-04-06 12:32:37 +1000479 SSH_VERSION);
Damien Miller037a0dc1999-12-07 15:38:31 +1100480 if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
Damien Miller95def091999-11-25 00:26:21 +1100481 fatal("write: %.100s", strerror(errno));
Damien Miller1383bd82000-04-06 12:32:37 +1000482 client_version_string = xstrdup(buf);
483 chop(client_version_string);
484 chop(server_version_string);
485 debug("Local version string %.100s", client_version_string);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000486}
487
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000488/* defaults to 'no' */
Ben Lindstrombba81212001-06-25 05:01:22 +0000489static int
Damien Millere3980042001-10-10 15:02:03 +1000490confirm(const char *prompt)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000491{
Damien Miller49d795c2002-01-22 23:34:12 +1100492 const char *msg, *again = "Please type 'yes' or 'no': ";
493 char *p;
494 int ret = -1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000495
Ben Lindstromb6c06d92001-02-10 23:21:09 +0000496 if (options.batch_mode)
497 return 0;
Damien Miller49d795c2002-01-22 23:34:12 +1100498 for (msg = prompt;;msg = again) {
499 p = read_passphrase(msg, RP_ECHO);
500 if (p == NULL ||
501 (p[0] == '\0') || (p[0] == '\n') ||
502 strncasecmp(p, "no", 2) == 0)
503 ret = 0;
504 if (strncasecmp(p, "yes", 3) == 0)
505 ret = 1;
506 if (p)
507 xfree(p);
508 if (ret != -1)
509 return ret;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000510 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000511}
512
Damien Miller95def091999-11-25 00:26:21 +1100513/*
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000514 * check whether the supplied host key is valid, return -1 if the key
515 * is not valid. the user_hostfile will not be updated if 'readonly' is true.
Damien Miller95def091999-11-25 00:26:21 +1100516 */
Damien Millera34a28b1999-12-14 10:47:15 +1100517
Ben Lindstrombba81212001-06-25 05:01:22 +0000518static int
Damien Millereba71ba2000-04-29 23:57:08 +1000519check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000520 int readonly, const char *user_hostfile, const char *system_hostfile)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000521{
Damien Miller450a7a12000-03-26 13:04:51 +1000522 Key *file_key;
Damien Millere247cc42000-05-07 12:03:14 +1000523 char *type = key_type(host_key);
Damien Millera34a28b1999-12-14 10:47:15 +1100524 char *ip = NULL;
Ben Lindstromcfccef92001-03-13 04:57:58 +0000525 char hostline[1000], *hostp, *fp;
Damien Miller95def091999-11-25 00:26:21 +1100526 HostStatus host_status;
527 HostStatus ip_status;
Damien Miller34132e52000-01-14 15:45:46 +1100528 int local = 0, host_ip_differ = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100529 int salen;
Damien Miller34132e52000-01-14 15:45:46 +1100530 char ntop[NI_MAXHOST];
Damien Miller49d795c2002-01-22 23:34:12 +1100531 char msg[1024];
532 int len, host_line, ip_line;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000533 const char *host_file = NULL, *ip_file = NULL;
Damien Miller34132e52000-01-14 15:45:46 +1100534
535 /*
536 * Force accepting of the host key for loopback/localhost. The
537 * problem is that if the home directory is NFS-mounted to multiple
538 * machines, localhost will refer to a different machine in each of
539 * them, and the user will get bogus HOST_CHANGED warnings. This
540 * essentially disables host authentication for localhost; however,
541 * this is probably not a real problem.
542 */
Damien Millereba71ba2000-04-29 23:57:08 +1000543 /** hostaddr == 0! */
Damien Miller34132e52000-01-14 15:45:46 +1100544 switch (hostaddr->sa_family) {
545 case AF_INET:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000546 local = (ntohl(((struct sockaddr_in *)hostaddr)->
547 sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
Damien Millereaf99942000-01-19 13:45:07 +1100548 salen = sizeof(struct sockaddr_in);
Damien Miller34132e52000-01-14 15:45:46 +1100549 break;
550 case AF_INET6:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000551 local = IN6_IS_ADDR_LOOPBACK(
552 &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
Damien Millereaf99942000-01-19 13:45:07 +1100553 salen = sizeof(struct sockaddr_in6);
Damien Miller34132e52000-01-14 15:45:46 +1100554 break;
555 default:
556 local = 0;
Damien Millereaf99942000-01-19 13:45:07 +1100557 salen = sizeof(struct sockaddr_storage);
Damien Miller34132e52000-01-14 15:45:46 +1100558 break;
559 }
Ben Lindstrom3cecc9a2001-10-03 17:39:38 +0000560 if (options.no_host_authentication_for_localhost == 1 && local &&
561 options.host_key_alias == NULL) {
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000562 debug("Forcing accepting of host key for "
563 "loopback/localhost.");
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000564 return 0;
Damien Miller34132e52000-01-14 15:45:46 +1100565 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000566
Damien Milleraae6c611999-12-06 11:47:28 +1100567 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000568 * We don't have the remote ip-address for connections
569 * using a proxy command
Damien Milleraae6c611999-12-06 11:47:28 +1100570 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000571 if (options.proxy_command == NULL) {
572 if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
573 NULL, 0, NI_NUMERICHOST) != 0)
574 fatal("check_host_key: getnameinfo failed");
575 ip = xstrdup(ntop);
576 } else {
577 ip = xstrdup("<no hostip for proxy command>");
578 }
579 /*
580 * Turn off check_host_ip if the connection is to localhost, via proxy
581 * command or if we don't have a hostname to compare with
582 */
583 if (options.check_host_ip &&
584 (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
Damien Milleraae6c611999-12-06 11:47:28 +1100585 options.check_host_ip = 0;
586
Damien Millera34a28b1999-12-14 10:47:15 +1100587 /*
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000588 * Allow the user to record the key under a different name. This is
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000589 * useful for ssh tunneling over forwarded connections or if you run
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000590 * multiple sshd's on different ports on the same machine.
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000591 */
592 if (options.host_key_alias != NULL) {
593 host = options.host_key_alias;
594 debug("using hostkeyalias: %s", host);
595 }
596
597 /*
Damien Millera34a28b1999-12-14 10:47:15 +1100598 * Store the host key from the known host file in here so that we can
599 * compare it with the key for the IP address.
600 */
Damien Miller450a7a12000-03-26 13:04:51 +1000601 file_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000602
Damien Miller5428f641999-11-25 11:54:57 +1100603 /*
604 * Check if the host key is present in the user\'s list of known
605 * hosts or in the systemwide list.
606 */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000607 host_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000608 host_status = check_host_in_hostfile(host_file, host, host_key,
Damien Miller9f0f5c62001-12-21 14:45:46 +1100609 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000610 if (host_status == HOST_NEW) {
611 host_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000612 host_status = check_host_in_hostfile(host_file, host, host_key,
613 file_key, &host_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000614 }
Damien Miller5428f641999-11-25 11:54:57 +1100615 /*
Damien Miller5428f641999-11-25 11:54:57 +1100616 * Also perform check for the ip address, skip the check if we are
617 * localhost or the hostname was an ip address to begin with
618 */
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000619 if (options.check_host_ip) {
Damien Miller450a7a12000-03-26 13:04:51 +1000620 Key *ip_key = key_new(host_key->type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000621
Ben Lindstrom46c16222000-12-22 01:43:59 +0000622 ip_file = user_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000623 ip_status = check_host_in_hostfile(ip_file, ip, host_key,
624 ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000625 if (ip_status == HOST_NEW) {
626 ip_file = system_hostfile;
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000627 ip_status = check_host_in_hostfile(ip_file, ip,
628 host_key, ip_key, &ip_line);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000629 }
Damien Miller95def091999-11-25 00:26:21 +1100630 if (host_status == HOST_CHANGED &&
Damien Miller450a7a12000-03-26 13:04:51 +1000631 (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
Damien Miller95def091999-11-25 00:26:21 +1100632 host_ip_differ = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000633
Damien Miller450a7a12000-03-26 13:04:51 +1000634 key_free(ip_key);
Damien Miller95def091999-11-25 00:26:21 +1100635 } else
636 ip_status = host_status;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000637
Damien Miller450a7a12000-03-26 13:04:51 +1000638 key_free(file_key);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000639
Damien Miller95def091999-11-25 00:26:21 +1100640 switch (host_status) {
641 case HOST_OK:
642 /* The host is known and the key matches. */
Damien Millere247cc42000-05-07 12:03:14 +1000643 debug("Host '%.200s' is known and matches the %s host key.",
644 host, type);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000645 debug("Found key in %s:%d", host_file, host_line);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000646 if (options.check_host_ip && ip_status == HOST_NEW) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000647 if (readonly)
648 log("%s host key for IP address "
649 "'%.128s' not in list of known hosts.",
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000650 type, ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000651 else if (!add_host_to_hostfile(user_hostfile, ip,
Damien Miller9f0f5c62001-12-21 14:45:46 +1100652 host_key))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000653 log("Failed to add the %s host key for IP "
654 "address '%.128s' to the list of known "
655 "hosts (%.30s).", type, ip, user_hostfile);
656 else
657 log("Warning: Permanently added the %s host "
658 "key for IP address '%.128s' to the list "
659 "of known hosts.", type, ip);
Damien Miller95def091999-11-25 00:26:21 +1100660 }
661 break;
662 case HOST_NEW:
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000663 if (readonly)
664 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100665 /* The host is new. */
666 if (options.strict_host_key_checking == 1) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000667 /*
668 * User has requested strict host key checking. We
669 * will not add the host key automatically. The only
670 * alternative left is to abort.
671 */
672 error("No %s host key is known for %.200s and you "
673 "have requested strict checking.", type, host);
674 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100675 } else if (options.strict_host_key_checking == 2) {
676 /* The default */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000677 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller49d795c2002-01-22 23:34:12 +1100678 snprintf(msg, sizeof(msg),
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000679 "The authenticity of host '%.200s (%s)' can't be "
680 "established.\n"
Damien Millere247cc42000-05-07 12:03:14 +1000681 "%s key fingerprint is %s.\n"
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000682 "Are you sure you want to continue connecting "
683 "(yes/no)? ", host, ip, type, fp);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000684 xfree(fp);
Damien Miller49d795c2002-01-22 23:34:12 +1100685 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000686 goto fail;
Damien Miller95def091999-11-25 00:26:21 +1100687 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000688 if (options.check_host_ip && ip_status == HOST_NEW) {
Damien Miller95def091999-11-25 00:26:21 +1100689 snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
690 hostp = hostline;
691 } else
692 hostp = host;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000693
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000694 /*
695 * If not in strict mode, add the key automatically to the
696 * local known_hosts file.
697 */
Damien Millereba71ba2000-04-29 23:57:08 +1000698 if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000699 log("Failed to add the host to the list of known "
700 "hosts (%.500s).", user_hostfile);
Damien Miller95def091999-11-25 00:26:21 +1100701 else
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000702 log("Warning: Permanently added '%.200s' (%s) to the "
703 "list of known hosts.", hostp, type);
Damien Miller95def091999-11-25 00:26:21 +1100704 break;
705 case HOST_CHANGED:
706 if (options.check_host_ip && host_ip_differ) {
707 char *msg;
708 if (ip_status == HOST_NEW)
709 msg = "is unknown";
710 else if (ip_status == HOST_OK)
711 msg = "is unchanged";
712 else
713 msg = "has a different value";
714 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
715 error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
716 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millere247cc42000-05-07 12:03:14 +1000717 error("The %s host key for %s has changed,", type, host);
Damien Miller95def091999-11-25 00:26:21 +1100718 error("and the key for the according IP address %s", ip);
719 error("%s. This could either mean that", msg);
720 error("DNS SPOOFING is happening or the IP address for the host");
Ben Lindstrom46c16222000-12-22 01:43:59 +0000721 error("and its host key have changed at the same time.");
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000722 if (ip_status != HOST_NEW)
Ben Lindstrom46c16222000-12-22 01:43:59 +0000723 error("Offending key for IP in %s:%d", ip_file, ip_line);
Damien Miller95def091999-11-25 00:26:21 +1100724 }
725 /* The host key has changed. */
Ben Lindstromcfccef92001-03-13 04:57:58 +0000726 fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
Damien Miller95def091999-11-25 00:26:21 +1100727 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
Damien Millerf039bad1999-12-21 20:57:20 +1100728 error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
Damien Miller95def091999-11-25 00:26:21 +1100729 error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
730 error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
731 error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
Damien Millere247cc42000-05-07 12:03:14 +1000732 error("It is also possible that the %s host key has just been changed.", type);
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000733 error("The fingerprint for the %s key sent by the remote host is\n%s.",
Ben Lindstromcfccef92001-03-13 04:57:58 +0000734 type, fp);
Damien Miller95def091999-11-25 00:26:21 +1100735 error("Please contact your system administrator.");
736 error("Add correct host key in %.100s to get rid of this message.",
Ben Lindstrom4dccfa52000-12-28 16:40:05 +0000737 user_hostfile);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000738 error("Offending key in %s:%d", host_file, host_line);
Ben Lindstromcfccef92001-03-13 04:57:58 +0000739 xfree(fp);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000740
Damien Miller5428f641999-11-25 11:54:57 +1100741 /*
742 * If strict host key checking is in use, the user will have
743 * to edit the key manually and we can only abort.
744 */
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000745 if (options.strict_host_key_checking) {
746 error("%s host key for %.200s has changed and you have "
747 "requested strict checking.", type, host);
748 goto fail;
749 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000750
Damien Miller5428f641999-11-25 11:54:57 +1100751 /*
752 * If strict host key checking has not been requested, allow
753 * the connection but without password authentication or
754 * agent forwarding.
755 */
Damien Miller95def091999-11-25 00:26:21 +1100756 if (options.password_authentication) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000757 error("Password authentication is disabled to avoid "
758 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100759 options.password_authentication = 0;
760 }
761 if (options.forward_agent) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000762 error("Agent forwarding is disabled to avoid "
763 "man-in-the-middle attacks.");
Damien Miller95def091999-11-25 00:26:21 +1100764 options.forward_agent = 0;
765 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000766 if (options.forward_x11) {
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000767 error("X11 forwarding is disabled to avoid "
768 "man-in-the-middle attacks.");
Ben Lindstromc72745a2000-12-02 19:03:54 +0000769 options.forward_x11 = 0;
770 }
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000771 if (options.num_local_forwards > 0 ||
772 options.num_remote_forwards > 0) {
773 error("Port forwarding is disabled to avoid "
774 "man-in-the-middle attacks.");
775 options.num_local_forwards =
Damien Miller9f0f5c62001-12-21 14:45:46 +1100776 options.num_remote_forwards = 0;
Ben Lindstromc72745a2000-12-02 19:03:54 +0000777 }
Damien Miller5428f641999-11-25 11:54:57 +1100778 /*
779 * XXX Should permit the user to change to use the new id.
780 * This could be done by converting the host key to an
781 * identifying sentence, tell that the host identifies itself
782 * by that sentence, and ask the user if he/she whishes to
783 * accept the authentication.
784 */
Damien Miller95def091999-11-25 00:26:21 +1100785 break;
786 }
Ben Lindstromc72745a2000-12-02 19:03:54 +0000787
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000788 if (options.check_host_ip && host_status != HOST_CHANGED &&
789 ip_status == HOST_CHANGED) {
Damien Miller49d795c2002-01-22 23:34:12 +1100790 snprintf(msg, sizeof(msg),
791 "Warning: the %s host key for '%.200s' "
792 "differs from the key for the IP address '%.128s'"
793 "\nOffending key for IP in %s:%d",
794 type, host, ip, ip_file, ip_line);
795 if (host_status == HOST_OK) {
796 len = strlen(msg);
797 snprintf(msg + len, sizeof(msg) - len,
798 "\nMatching host key in %s:%d",
799 host_file, host_line);
800 }
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000801 if (options.strict_host_key_checking == 1) {
Damien Miller49d795c2002-01-22 23:34:12 +1100802 log(msg);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000803 error("Exiting, you have requested strict checking.");
804 goto fail;
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000805 } else if (options.strict_host_key_checking == 2) {
Damien Miller49d795c2002-01-22 23:34:12 +1100806 strlcat(msg, "\nAre you sure you want "
807 "to continue connecting (yes/no)? ", sizeof(msg));
808 if (!confirm(msg))
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000809 goto fail;
Damien Miller49d795c2002-01-22 23:34:12 +1100810 } else {
811 log(msg);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000812 }
813 }
814
Ben Lindstromc72745a2000-12-02 19:03:54 +0000815 xfree(ip);
Ben Lindstromd6481ea2001-06-25 04:37:41 +0000816 return 0;
817
818fail:
819 xfree(ip);
820 return -1;
821}
822
823int
824verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
825{
826 struct stat st;
827
828 /* return ok if the key can be found in an old keyfile */
829 if (stat(options.system_hostfile2, &st) == 0 ||
830 stat(options.user_hostfile2, &st) == 0) {
831 if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
832 options.user_hostfile2, options.system_hostfile2) == 0)
833 return 0;
834 }
835 return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
836 options.user_hostfile, options.system_hostfile);
Damien Millera34a28b1999-12-14 10:47:15 +1100837}
Damien Miller037a0dc1999-12-07 15:38:31 +1100838
Damien Miller396691a2000-01-20 22:44:08 +1100839/*
840 * Starts a dialog with the server, and authenticates the current user on the
841 * server. This does not need any extra privileges. The basic connection
842 * to the server must already have been established before this is called.
843 * If login fails, this function prints an error and never returns.
844 * This function does not require super-user privileges.
845 */
846void
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000847ssh_login(Key **keys, int nkeys, const char *orighost,
Ben Lindstrom3fcf1a22001-04-08 18:26:59 +0000848 struct sockaddr *hostaddr, struct passwd *pw)
Damien Miller396691a2000-01-20 22:44:08 +1100849{
850 char *host, *cp;
Damien Millereba71ba2000-04-29 23:57:08 +1000851 char *server_user, *local_user;
852
Damien Millereba71ba2000-04-29 23:57:08 +1000853 local_user = xstrdup(pw->pw_name);
854 server_user = options.user ? options.user : local_user;
Damien Miller396691a2000-01-20 22:44:08 +1100855
856 /* Convert the user-supplied hostname into all lowercase. */
857 host = xstrdup(orighost);
858 for (cp = host; *cp; cp++)
859 if (isupper(*cp))
860 *cp = tolower(*cp);
861
862 /* Exchange protocol version identification strings with the server. */
863 ssh_exchange_identification();
864
865 /* Put the connection into non-blocking mode. */
866 packet_set_nonblocking();
867
Damien Miller396691a2000-01-20 22:44:08 +1100868 /* key exchange */
Damien Miller396691a2000-01-20 22:44:08 +1100869 /* authenticate user */
Damien Miller1383bd82000-04-06 12:32:37 +1000870 if (compat20) {
871 ssh_kex2(host, hostaddr);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000872 ssh_userauth2(local_user, server_user, host, keys, nkeys);
Damien Miller1383bd82000-04-06 12:32:37 +1000873 } else {
Damien Miller1383bd82000-04-06 12:32:37 +1000874 ssh_kex(host, hostaddr);
Ben Lindstrom5eabda32001-04-12 23:34:34 +0000875 ssh_userauth1(local_user, server_user, host, keys, nkeys);
Damien Miller1383bd82000-04-06 12:32:37 +1000876 }
Damien Miller396691a2000-01-20 22:44:08 +1100877}
Damien Miller79438cc2001-02-16 12:34:57 +1100878
879void
880ssh_put_password(char *password)
881{
882 int size;
883 char *padded;
884
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000885 if (datafellows & SSH_BUG_PASSWORDPAD) {
Ben Lindstrom664408d2001-06-09 01:42:01 +0000886 packet_put_cstring(password);
Ben Lindstromd20d0f32001-03-10 17:22:20 +0000887 return;
888 }
Damien Miller79438cc2001-02-16 12:34:57 +1100889 size = roundup(strlen(password) + 1, 32);
890 padded = xmalloc(size);
891 memset(padded, 0, size);
892 strlcpy(padded, password, size);
893 packet_put_string(padded, size);
894 memset(padded, 0, size);
895 xfree(padded);
896}