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52e1856c | 1 | /* $OpenBSD: sshconnect.c,v 1.218 2010/01/13 00:19:04 dtucker Exp $ */ |
8efc0c15 | 2 | /* |
5260325f | 3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
5260325f | 6 | * Code to connect to a remote host, and to perform the client side of the |
7 | * login (authentication) dialog. | |
bcbf86ec | 8 | * |
9 | * As far as I am concerned, the code I have written for this software | |
10 | * can be used freely for any purpose. Any derived versions of this | |
11 | * software must be clearly marked as such, and if the derived work is | |
12 | * incompatible with the protocol description in the RFC file, it must be | |
13 | * called by a name other than "ssh" or "Secure Shell". | |
5260325f | 14 | */ |
8efc0c15 | 15 | |
16 | #include "includes.h" | |
aa2eae64 | 17 | |
18 | #include <sys/types.h> | |
19 | #include <sys/wait.h> | |
4095f623 | 20 | #include <sys/stat.h> |
9794d008 | 21 | #include <sys/socket.h> |
e264ac72 | 22 | #ifdef HAVE_SYS_TIME_H |
23 | # include <sys/time.h> | |
24 | #endif | |
9794d008 | 25 | |
26 | #include <netinet/in.h> | |
5e837c7b | 27 | #include <arpa/inet.h> |
a75f5360 | 28 | |
b6438382 | 29 | #include <ctype.h> |
028094f4 | 30 | #include <errno.h> |
fe5bc072 | 31 | #include <fcntl.h> |
28cb0a43 | 32 | #include <netdb.h> |
b5b88c19 | 33 | #ifdef HAVE_PATHS_H |
a75f5360 | 34 | #include <paths.h> |
b5b88c19 | 35 | #endif |
b1842393 | 36 | #include <pwd.h> |
24436b92 | 37 | #include <stdarg.h> |
cf851879 | 38 | #include <stdio.h> |
ffa517a8 | 39 | #include <stdlib.h> |
00146caa | 40 | #include <string.h> |
5188ba17 | 41 | #include <unistd.h> |
8efc0c15 | 42 | |
8efc0c15 | 43 | #include "xmalloc.h" |
31652869 | 44 | #include "key.h" |
45 | #include "hostfile.h" | |
46 | #include "ssh.h" | |
8efc0c15 | 47 | #include "rsa.h" |
8ce64345 | 48 | #include "buffer.h" |
8efc0c15 | 49 | #include "packet.h" |
8efc0c15 | 50 | #include "uidswap.h" |
51 | #include "compat.h" | |
4fe2af09 | 52 | #include "key.h" |
a306f2dd | 53 | #include "sshconnect.h" |
4fe2af09 | 54 | #include "hostfile.h" |
42f11eb2 | 55 | #include "log.h" |
56 | #include "readconf.h" | |
57 | #include "atomicio.h" | |
58 | #include "misc.h" | |
21289cd0 | 59 | #include "dns.h" |
d0137ef8 | 60 | #include "roaming.h" |
28015df4 | 61 | #include "version.h" |
21289cd0 | 62 | |
a306f2dd | 63 | char *client_version_string = NULL; |
64 | char *server_version_string = NULL; | |
8ce64345 | 65 | |
ed82a2a9 | 66 | static int matching_host_key_dns = 0; |
1432b5c4 | 67 | |
3fb156df | 68 | /* import */ |
57112b5a | 69 | extern Options options; |
48e671d5 | 70 | extern char *__progname; |
3fb156df | 71 | extern uid_t original_real_uid; |
72 | extern uid_t original_effective_uid; | |
6939bbd4 | 73 | extern pid_t proxy_command_pid; |
57112b5a | 74 | |
8a48a7ef | 75 | static int show_other_keys(const char *, Key *); |
1a1bc5d5 | 76 | static void warn_changed_key(Key *); |
8a48a7ef | 77 | |
5260325f | 78 | /* |
79 | * Connect to the given ssh server using a proxy command. | |
80 | */ | |
396c147e | 81 | static int |
3fb156df | 82 | ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) |
8efc0c15 | 83 | { |
a980cbd7 | 84 | char *command_string, *tmp; |
5260325f | 85 | int pin[2], pout[2]; |
9da5c3c9 | 86 | pid_t pid; |
3af8ef1e | 87 | char *shell, strport[NI_MAXSERV]; |
88 | ||
89 | if ((shell = getenv("SHELL")) == NULL) | |
90 | shell = _PATH_BSHELL; | |
5260325f | 91 | |
92 | /* Convert the port number into a string. */ | |
48e671d5 | 93 | snprintf(strport, sizeof strport, "%hu", port); |
5260325f | 94 | |
6939bbd4 | 95 | /* |
96 | * Build the final command string in the buffer by making the | |
97 | * appropriate substitutions to the given proxy command. | |
98 | * | |
aff51935 | 99 | * Use "exec" to avoid "sh -c" processes on some platforms |
6939bbd4 | 100 | * (e.g. Solaris) |
101 | */ | |
52e3daed | 102 | xasprintf(&tmp, "exec %s", proxy_command); |
a980cbd7 | 103 | command_string = percent_expand(tmp, "h", host, |
104 | "p", strport, (char *)NULL); | |
105 | xfree(tmp); | |
5260325f | 106 | |
107 | /* Create pipes for communicating with the proxy. */ | |
108 | if (pipe(pin) < 0 || pipe(pout) < 0) | |
109 | fatal("Could not create pipes to communicate with the proxy: %.100s", | |
184eed6a | 110 | strerror(errno)); |
5260325f | 111 | |
112 | debug("Executing proxy command: %.500s", command_string); | |
113 | ||
114 | /* Fork and execute the proxy command. */ | |
115 | if ((pid = fork()) == 0) { | |
116 | char *argv[10]; | |
117 | ||
118 | /* Child. Permanently give up superuser privileges. */ | |
3c33c1b6 | 119 | permanently_drop_suid(original_real_uid); |
5260325f | 120 | |
121 | /* Redirect stdin and stdout. */ | |
122 | close(pin[1]); | |
123 | if (pin[0] != 0) { | |
124 | if (dup2(pin[0], 0) < 0) | |
125 | perror("dup2 stdin"); | |
126 | close(pin[0]); | |
127 | } | |
128 | close(pout[0]); | |
129 | if (dup2(pout[1], 1) < 0) | |
130 | perror("dup2 stdout"); | |
131 | /* Cannot be 1 because pin allocated two descriptors. */ | |
132 | close(pout[1]); | |
133 | ||
134 | /* Stderr is left as it is so that error messages get | |
135 | printed on the user's terminal. */ | |
3af8ef1e | 136 | argv[0] = shell; |
5260325f | 137 | argv[1] = "-c"; |
138 | argv[2] = command_string; | |
139 | argv[3] = NULL; | |
140 | ||
141 | /* Execute the proxy command. Note that we gave up any | |
142 | extra privileges above. */ | |
328654d8 | 143 | execv(argv[0], argv); |
144 | perror(argv[0]); | |
5260325f | 145 | exit(1); |
8efc0c15 | 146 | } |
5260325f | 147 | /* Parent. */ |
148 | if (pid < 0) | |
149 | fatal("fork failed: %.100s", strerror(errno)); | |
6939bbd4 | 150 | else |
151 | proxy_command_pid = pid; /* save pid to clean up later */ | |
5260325f | 152 | |
153 | /* Close child side of the descriptors. */ | |
154 | close(pin[0]); | |
155 | close(pout[1]); | |
156 | ||
157 | /* Free the command name. */ | |
a980cbd7 | 158 | xfree(command_string); |
5260325f | 159 | |
160 | /* Set the connection file descriptors. */ | |
161 | packet_set_connection(pout[0], pin[1]); | |
bc2d97c8 | 162 | packet_set_timeout(options.server_alive_interval, |
163 | options.server_alive_count_max); | |
8efc0c15 | 164 | |
ce773142 | 165 | /* Indicate OK return */ |
166 | return 0; | |
5260325f | 167 | } |
8efc0c15 | 168 | |
5260325f | 169 | /* |
170 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
171 | */ | |
396c147e | 172 | static int |
3e131a6d | 173 | ssh_create_socket(int privileged, struct addrinfo *ai) |
8efc0c15 | 174 | { |
3435f5a6 | 175 | int sock, gaierr; |
176 | struct addrinfo hints, *res; | |
5260325f | 177 | |
aa3378df | 178 | /* |
179 | * If we are running as root and want to connect to a privileged | |
180 | * port, bind our own socket to a privileged port. | |
181 | */ | |
5260325f | 182 | if (privileged) { |
183 | int p = IPPORT_RESERVED - 1; | |
3fb156df | 184 | PRIV_START; |
3e131a6d | 185 | sock = rresvport_af(&p, ai->ai_family); |
3fb156df | 186 | PRIV_END; |
5260325f | 187 | if (sock < 0) |
3e131a6d | 188 | error("rresvport: af=%d %.100s", ai->ai_family, |
189 | strerror(errno)); | |
c8d54615 | 190 | else |
191 | debug("Allocated local port %d.", p); | |
3435f5a6 | 192 | return sock; |
193 | } | |
16d64584 | 194 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); |
fe5bc072 | 195 | if (sock < 0) { |
3435f5a6 | 196 | error("socket: %.100s", strerror(errno)); |
fe5bc072 | 197 | return -1; |
198 | } | |
199 | fcntl(sock, F_SETFD, FD_CLOEXEC); | |
3435f5a6 | 200 | |
201 | /* Bind the socket to an alternative local IP address */ | |
202 | if (options.bind_address == NULL) | |
203 | return sock; | |
204 | ||
205 | memset(&hints, 0, sizeof(hints)); | |
3e131a6d | 206 | hints.ai_family = ai->ai_family; |
207 | hints.ai_socktype = ai->ai_socktype; | |
208 | hints.ai_protocol = ai->ai_protocol; | |
3435f5a6 | 209 | hints.ai_flags = AI_PASSIVE; |
c5daf22b | 210 | gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res); |
3435f5a6 | 211 | if (gaierr) { |
212 | error("getaddrinfo: %s: %s", options.bind_address, | |
bb4626fe | 213 | ssh_gai_strerror(gaierr)); |
3435f5a6 | 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; | |
5260325f | 222 | } |
3435f5a6 | 223 | freeaddrinfo(res); |
5260325f | 224 | return sock; |
8efc0c15 | 225 | } |
226 | ||
09ab3296 | 227 | static int |
228 | timeout_connect(int sockfd, const struct sockaddr *serv_addr, | |
71300a43 | 229 | socklen_t addrlen, int *timeoutp) |
09ab3296 | 230 | { |
231 | fd_set *fdset; | |
71300a43 | 232 | struct timeval tv, t_start; |
09ab3296 | 233 | socklen_t optlen; |
52e3daed | 234 | int optval, rc, result = -1; |
09ab3296 | 235 | |
71300a43 | 236 | gettimeofday(&t_start, NULL); |
237 | ||
238 | if (*timeoutp <= 0) { | |
239 | result = connect(sockfd, serv_addr, addrlen); | |
240 | goto done; | |
241 | } | |
09ab3296 | 242 | |
2daf1db1 | 243 | set_nonblock(sockfd); |
09ab3296 | 244 | rc = connect(sockfd, serv_addr, addrlen); |
2daf1db1 | 245 | if (rc == 0) { |
246 | unset_nonblock(sockfd); | |
71300a43 | 247 | result = 0; |
248 | goto done; | |
249 | } | |
250 | if (errno != EINPROGRESS) { | |
251 | result = -1; | |
252 | goto done; | |
2daf1db1 | 253 | } |
09ab3296 | 254 | |
52e3daed | 255 | fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS), |
256 | sizeof(fd_mask)); | |
09ab3296 | 257 | FD_SET(sockfd, fdset); |
71300a43 | 258 | ms_to_timeval(&tv, *timeoutp); |
09ab3296 | 259 | |
f8cc7664 | 260 | for (;;) { |
09ab3296 | 261 | rc = select(sockfd + 1, NULL, fdset, NULL, &tv); |
262 | if (rc != -1 || errno != EINTR) | |
263 | break; | |
264 | } | |
265 | ||
f8cc7664 | 266 | switch (rc) { |
09ab3296 | 267 | case 0: |
268 | /* Timed out */ | |
269 | errno = ETIMEDOUT; | |
da54f5be | 270 | break; |
09ab3296 | 271 | case -1: |
272 | /* Select error */ | |
aff51935 | 273 | debug("select: %s", strerror(errno)); |
da54f5be | 274 | break; |
09ab3296 | 275 | case 1: |
276 | /* Completed or failed */ | |
277 | optval = 0; | |
278 | optlen = sizeof(optval); | |
aff51935 | 279 | if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, |
ce26c02a | 280 | &optlen) == -1) { |
aff51935 | 281 | debug("getsockopt: %s", strerror(errno)); |
da54f5be | 282 | break; |
ce26c02a | 283 | } |
09ab3296 | 284 | if (optval != 0) { |
285 | errno = optval; | |
da54f5be | 286 | break; |
09ab3296 | 287 | } |
da54f5be | 288 | result = 0; |
2daf1db1 | 289 | unset_nonblock(sockfd); |
09ab3296 | 290 | break; |
291 | default: | |
292 | /* Should not occur */ | |
293 | fatal("Bogus return (%d) from select()", rc); | |
294 | } | |
295 | ||
da54f5be | 296 | xfree(fdset); |
71300a43 | 297 | |
298 | done: | |
299 | if (result == 0 && *timeoutp > 0) { | |
300 | ms_subtract_diff(&t_start, timeoutp); | |
301 | if (*timeoutp <= 0) { | |
302 | errno = ETIMEDOUT; | |
303 | result = -1; | |
304 | } | |
305 | } | |
306 | ||
da54f5be | 307 | return (result); |
09ab3296 | 308 | } |
309 | ||
5260325f | 310 | /* |
48e671d5 | 311 | * Opens a TCP/IP connection to the remote server on the given host. |
312 | * The address of the remote host will be returned in hostaddr. | |
3fb156df | 313 | * If port is 0, the default port will be used. If needpriv is true, |
5260325f | 314 | * a privileged port will be allocated to make the connection. |
3fb156df | 315 | * This requires super-user privileges if needpriv is true. |
5260325f | 316 | * Connection_attempts specifies the maximum number of tries (one per |
317 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
318 | * and %p substituted for host and port, respectively) to use to contact | |
319 | * the daemon. | |
320 | */ | |
321 | int | |
48e671d5 | 322 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
71300a43 | 323 | u_short port, int family, int connection_attempts, int *timeout_ms, |
324 | int want_keepalive, int needpriv, const char *proxy_command) | |
8efc0c15 | 325 | { |
b5c334cc | 326 | int gaierr; |
327 | int on = 1; | |
48e671d5 | 328 | int sock = -1, attempt; |
48e671d5 | 329 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
b5c334cc | 330 | struct addrinfo hints, *ai, *aitop; |
5260325f | 331 | |
a77673cc | 332 | debug2("ssh_connect: needpriv %d", needpriv); |
5260325f | 333 | |
5260325f | 334 | /* If a proxy command is given, connect using it. */ |
335 | if (proxy_command != NULL) | |
3fb156df | 336 | return ssh_proxy_connect(host, port, proxy_command); |
5260325f | 337 | |
338 | /* No proxy command. */ | |
339 | ||
48e671d5 | 340 | memset(&hints, 0, sizeof(hints)); |
dab89049 | 341 | hints.ai_family = family; |
48e671d5 | 342 | hints.ai_socktype = SOCK_STREAM; |
d6133f43 | 343 | snprintf(strport, sizeof strport, "%u", port); |
48e671d5 | 344 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) |
bb4626fe | 345 | fatal("%s: Could not resolve hostname %.100s: %s", __progname, |
346 | host, ssh_gai_strerror(gaierr)); | |
5260325f | 347 | |
4439dde1 | 348 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
77903f77 | 349 | if (attempt > 0) { |
350 | /* Sleep a moment before retrying. */ | |
351 | sleep(1); | |
5260325f | 352 | debug("Trying again..."); |
77903f77 | 353 | } |
4439dde1 | 354 | /* |
355 | * Loop through addresses for this host, and try each one in | |
356 | * sequence until the connection succeeds. | |
357 | */ | |
48e671d5 | 358 | for (ai = aitop; ai; ai = ai->ai_next) { |
359 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
360 | continue; | |
361 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
362 | ntop, sizeof(ntop), strport, sizeof(strport), | |
363 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
364 | error("ssh_connect: getnameinfo failed"); | |
365 | continue; | |
366 | } | |
367 | debug("Connecting to %.200s [%.100s] port %s.", | |
368 | host, ntop, strport); | |
369 | ||
370 | /* Create a socket for connecting. */ | |
3e131a6d | 371 | sock = ssh_create_socket(needpriv, ai); |
48e671d5 | 372 | if (sock < 0) |
ce773142 | 373 | /* Any error is already output */ |
48e671d5 | 374 | continue; |
375 | ||
09ab3296 | 376 | if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, |
71300a43 | 377 | timeout_ms) >= 0) { |
48e671d5 | 378 | /* Successful connection. */ |
cd332296 | 379 | memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); |
5260325f | 380 | break; |
48e671d5 | 381 | } else { |
c750d869 | 382 | debug("connect to address %s port %s: %s", |
383 | ntop, strport, strerror(errno)); | |
5260325f | 384 | close(sock); |
4439dde1 | 385 | sock = -1; |
5260325f | 386 | } |
8efc0c15 | 387 | } |
4439dde1 | 388 | if (sock != -1) |
48e671d5 | 389 | break; /* Successful connection. */ |
5260325f | 390 | } |
48e671d5 | 391 | |
392 | freeaddrinfo(aitop); | |
393 | ||
5260325f | 394 | /* Return failure if we didn't get a successful connection. */ |
4439dde1 | 395 | if (sock == -1) { |
cf039bd1 | 396 | error("ssh: connect to host %s port %s: %s", |
9bd68577 | 397 | host, strport, strerror(errno)); |
cf039bd1 | 398 | return (-1); |
9bd68577 | 399 | } |
8efc0c15 | 400 | |
5260325f | 401 | debug("Connection established."); |
8efc0c15 | 402 | |
fd573618 | 403 | /* Set SO_KEEPALIVE if requested. */ |
71300a43 | 404 | if (want_keepalive && |
b5c334cc | 405 | setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, |
406 | sizeof(on)) < 0) | |
407 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
8efc0c15 | 408 | |
5260325f | 409 | /* Set the connection. */ |
410 | packet_set_connection(sock, sock); | |
bc2d97c8 | 411 | packet_set_timeout(options.server_alive_interval, |
412 | options.server_alive_count_max); | |
8efc0c15 | 413 | |
ce773142 | 414 | return 0; |
8efc0c15 | 415 | } |
416 | ||
5260325f | 417 | /* |
418 | * Waits for the server identification string, and sends our own | |
419 | * identification string. | |
420 | */ | |
5d4d25cd | 421 | void |
71300a43 | 422 | ssh_exchange_identification(int timeout_ms) |
8efc0c15 | 423 | { |
5260325f | 424 | char buf[256], remote_version[256]; /* must be same size! */ |
2ceb8101 | 425 | int remote_major, remote_minor, mismatch; |
5260325f | 426 | int connection_in = packet_get_connection_in(); |
427 | int connection_out = packet_get_connection_out(); | |
2b87da3b | 428 | int minor1 = PROTOCOL_MINOR_1; |
e5c76324 | 429 | u_int i, n; |
71300a43 | 430 | size_t len; |
431 | int fdsetsz, remaining, rc; | |
432 | struct timeval t_start, t_remaining; | |
433 | fd_set *fdset; | |
434 | ||
435 | fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask); | |
436 | fdset = xcalloc(1, fdsetsz); | |
5260325f | 437 | |
05624c18 | 438 | /* Read other side's version identification. */ |
71300a43 | 439 | remaining = timeout_ms; |
e5c76324 | 440 | for (n = 0;;) { |
38c295d6 | 441 | for (i = 0; i < sizeof(buf) - 1; i++) { |
71300a43 | 442 | if (timeout_ms > 0) { |
443 | gettimeofday(&t_start, NULL); | |
444 | ms_to_timeval(&t_remaining, remaining); | |
445 | FD_SET(connection_in, fdset); | |
446 | rc = select(connection_in + 1, fdset, NULL, | |
447 | fdset, &t_remaining); | |
448 | ms_subtract_diff(&t_start, &remaining); | |
449 | if (rc == 0 || remaining <= 0) | |
450 | fatal("Connection timed out during " | |
451 | "banner exchange"); | |
452 | if (rc == -1) { | |
453 | if (errno == EINTR) | |
454 | continue; | |
455 | fatal("ssh_exchange_identification: " | |
456 | "select: %s", strerror(errno)); | |
457 | } | |
458 | } | |
459 | ||
d0137ef8 | 460 | len = roaming_atomicio(read, connection_in, &buf[i], 1); |
05624c18 | 461 | |
56964485 | 462 | if (len != 1 && errno == EPIPE) |
71300a43 | 463 | fatal("ssh_exchange_identification: " |
464 | "Connection closed by remote host"); | |
05624c18 | 465 | else if (len != 1) |
71300a43 | 466 | fatal("ssh_exchange_identification: " |
467 | "read: %.100s", strerror(errno)); | |
38c295d6 | 468 | if (buf[i] == '\r') { |
469 | buf[i] = '\n'; | |
470 | buf[i + 1] = 0; | |
471 | continue; /**XXX wait for \n */ | |
472 | } | |
473 | if (buf[i] == '\n') { | |
474 | buf[i + 1] = 0; | |
475 | break; | |
476 | } | |
e5c76324 | 477 | if (++n > 65536) |
71300a43 | 478 | fatal("ssh_exchange_identification: " |
479 | "No banner received"); | |
5260325f | 480 | } |
38c295d6 | 481 | buf[sizeof(buf) - 1] = 0; |
482 | if (strncmp(buf, "SSH-", 4) == 0) | |
5260325f | 483 | break; |
38c295d6 | 484 | debug("ssh_exchange_identification: %s", buf); |
8efc0c15 | 485 | } |
8ce64345 | 486 | server_version_string = xstrdup(buf); |
71300a43 | 487 | xfree(fdset); |
5260325f | 488 | |
aa3378df | 489 | /* |
490 | * Check that the versions match. In future this might accept | |
491 | * several versions and set appropriate flags to handle them. | |
492 | */ | |
8ce64345 | 493 | if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", |
494 | &remote_major, &remote_minor, remote_version) != 3) | |
5260325f | 495 | fatal("Bad remote protocol version identification: '%.100s'", buf); |
496 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
184eed6a | 497 | remote_major, remote_minor, remote_version); |
5260325f | 498 | |
8ce64345 | 499 | compat_datafellows(remote_version); |
a8be9f80 | 500 | mismatch = 0; |
501 | ||
6aacefa7 | 502 | switch (remote_major) { |
a8be9f80 | 503 | case 1: |
504 | if (remote_minor == 99 && | |
505 | (options.protocol & SSH_PROTO_2) && | |
506 | !(options.protocol & SSH_PROTO_1_PREFERRED)) { | |
507 | enable_compat20(); | |
508 | break; | |
5260325f | 509 | } |
a8be9f80 | 510 | if (!(options.protocol & SSH_PROTO_1)) { |
511 | mismatch = 1; | |
512 | break; | |
513 | } | |
514 | if (remote_minor < 3) { | |
515 | fatal("Remote machine has too old SSH software version."); | |
fa08c86b | 516 | } else if (remote_minor == 3 || remote_minor == 4) { |
a8be9f80 | 517 | /* We speak 1.3, too. */ |
518 | enable_compat13(); | |
fa08c86b | 519 | minor1 = 3; |
a8be9f80 | 520 | if (options.forward_agent) { |
bbe88b6d | 521 | logit("Agent forwarding disabled for protocol 1.3"); |
a8be9f80 | 522 | options.forward_agent = 0; |
523 | } | |
524 | } | |
525 | break; | |
526 | case 2: | |
527 | if (options.protocol & SSH_PROTO_2) { | |
528 | enable_compat20(); | |
529 | break; | |
530 | } | |
531 | /* FALLTHROUGH */ | |
6ae2364d | 532 | default: |
a8be9f80 | 533 | mismatch = 1; |
534 | break; | |
8efc0c15 | 535 | } |
a8be9f80 | 536 | if (mismatch) |
5260325f | 537 | fatal("Protocol major versions differ: %d vs. %d", |
a8be9f80 | 538 | (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
539 | remote_major); | |
5260325f | 540 | /* Send our own protocol version identification. */ |
f9b45eaf | 541 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", |
a8be9f80 | 542 | compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
fa08c86b | 543 | compat20 ? PROTOCOL_MINOR_2 : minor1, |
f9b45eaf | 544 | SSH_VERSION, compat20 ? "\r\n" : "\n"); |
d0137ef8 | 545 | if (roaming_atomicio(vwrite, connection_out, buf, strlen(buf)) |
546 | != strlen(buf)) | |
5260325f | 547 | fatal("write: %.100s", strerror(errno)); |
8ce64345 | 548 | client_version_string = xstrdup(buf); |
549 | chop(client_version_string); | |
550 | chop(server_version_string); | |
551 | debug("Local version string %.100s", client_version_string); | |
8efc0c15 | 552 | } |
553 | ||
f21032a6 | 554 | /* defaults to 'no' */ |
396c147e | 555 | static int |
a2c92c4a | 556 | confirm(const char *prompt) |
8efc0c15 | 557 | { |
616a6b93 | 558 | const char *msg, *again = "Please type 'yes' or 'no': "; |
559 | char *p; | |
560 | int ret = -1; | |
5260325f | 561 | |
f21032a6 | 562 | if (options.batch_mode) |
563 | return 0; | |
616a6b93 | 564 | for (msg = prompt;;msg = again) { |
565 | p = read_passphrase(msg, RP_ECHO); | |
566 | if (p == NULL || | |
567 | (p[0] == '\0') || (p[0] == '\n') || | |
568 | strncasecmp(p, "no", 2) == 0) | |
569 | ret = 0; | |
f11fe301 | 570 | if (p && strncasecmp(p, "yes", 3) == 0) |
616a6b93 | 571 | ret = 1; |
572 | if (p) | |
573 | xfree(p); | |
574 | if (ret != -1) | |
575 | return ret; | |
8efc0c15 | 576 | } |
8efc0c15 | 577 | } |
578 | ||
5260325f | 579 | /* |
f49bc4f7 | 580 | * check whether the supplied host key is valid, return -1 if the key |
581 | * is not valid. the user_hostfile will not be updated if 'readonly' is true. | |
5260325f | 582 | */ |
331c3884 | 583 | #define RDRW 0 |
584 | #define RDONLY 1 | |
585 | #define ROQUIET 2 | |
396c147e | 586 | static int |
331c3884 | 587 | check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, |
588 | Key *host_key, int readonly, const char *user_hostfile, | |
589 | const char *system_hostfile) | |
8efc0c15 | 590 | { |
4fe2af09 | 591 | Key *file_key; |
b6c7b7b7 | 592 | const char *type = key_type(host_key); |
d4530052 | 593 | char *ip = NULL, *host = NULL; |
aff73c5f | 594 | char hostline[1000], *hostp, *fp, *ra; |
5260325f | 595 | HostStatus host_status; |
596 | HostStatus ip_status; | |
e79276c2 | 597 | int r, local = 0, host_ip_differ = 0; |
20af321f | 598 | int salen; |
48e671d5 | 599 | char ntop[NI_MAXHOST]; |
616a6b93 | 600 | char msg[1024]; |
979b31ed | 601 | int len, host_line, ip_line, cancelled_forwarding = 0; |
1e3b8b07 | 602 | const char *host_file = NULL, *ip_file = NULL; |
48e671d5 | 603 | |
604 | /* | |
605 | * Force accepting of the host key for loopback/localhost. The | |
606 | * problem is that if the home directory is NFS-mounted to multiple | |
607 | * machines, localhost will refer to a different machine in each of | |
608 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
609 | * essentially disables host authentication for localhost; however, | |
610 | * this is probably not a real problem. | |
611 | */ | |
a306f2dd | 612 | /** hostaddr == 0! */ |
48e671d5 | 613 | switch (hostaddr->sa_family) { |
614 | case AF_INET: | |
f49bc4f7 | 615 | local = (ntohl(((struct sockaddr_in *)hostaddr)-> |
4e2e5cfd | 616 | sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; |
20af321f | 617 | salen = sizeof(struct sockaddr_in); |
48e671d5 | 618 | break; |
619 | case AF_INET6: | |
f49bc4f7 | 620 | local = IN6_IS_ADDR_LOOPBACK( |
621 | &(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
20af321f | 622 | salen = sizeof(struct sockaddr_in6); |
48e671d5 | 623 | break; |
624 | default: | |
625 | local = 0; | |
20af321f | 626 | salen = sizeof(struct sockaddr_storage); |
48e671d5 | 627 | break; |
628 | } | |
8bbc048a | 629 | if (options.no_host_authentication_for_localhost == 1 && local && |
630 | options.host_key_alias == NULL) { | |
7c49df64 | 631 | debug("Forcing accepting of host key for " |
632 | "loopback/localhost."); | |
f49bc4f7 | 633 | return 0; |
48e671d5 | 634 | } |
5260325f | 635 | |
57112b5a | 636 | /* |
7c49df64 | 637 | * We don't have the remote ip-address for connections |
638 | * using a proxy command | |
639 | */ | |
640 | if (options.proxy_command == NULL) { | |
641 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), | |
642 | NULL, 0, NI_NUMERICHOST) != 0) | |
643 | fatal("check_host_key: getnameinfo failed"); | |
331c3884 | 644 | ip = put_host_port(ntop, port); |
7c49df64 | 645 | } else { |
646 | ip = xstrdup("<no hostip for proxy command>"); | |
647 | } | |
e907df41 | 648 | |
7c49df64 | 649 | /* |
650 | * Turn off check_host_ip if the connection is to localhost, via proxy | |
651 | * command or if we don't have a hostname to compare with | |
57112b5a | 652 | */ |
d4530052 | 653 | if (options.check_host_ip && (local || |
654 | strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) | |
57112b5a | 655 | options.check_host_ip = 0; |
656 | ||
8abcdba4 | 657 | /* |
d4530052 | 658 | * Allow the user to record the key under a different name or |
659 | * differentiate a non-standard port. This is useful for ssh | |
660 | * tunneling over forwarded connections or if you run multiple | |
661 | * sshd's on different ports on the same machine. | |
8abcdba4 | 662 | */ |
663 | if (options.host_key_alias != NULL) { | |
d4530052 | 664 | host = xstrdup(options.host_key_alias); |
8abcdba4 | 665 | debug("using hostkeyalias: %s", host); |
d4530052 | 666 | } else { |
331c3884 | 667 | host = put_host_port(hostname, port); |
8abcdba4 | 668 | } |
669 | ||
95f1eccc | 670 | /* |
671 | * Store the host key from the known host file in here so that we can | |
672 | * compare it with the key for the IP address. | |
673 | */ | |
4fe2af09 | 674 | file_key = key_new(host_key->type); |
5260325f | 675 | |
aa3378df | 676 | /* |
7b9b0103 | 677 | * Check if the host key is present in the user's list of known |
aa3378df | 678 | * hosts or in the systemwide list. |
679 | */ | |
1e3b8b07 | 680 | host_file = user_hostfile; |
f49bc4f7 | 681 | host_status = check_host_in_hostfile(host_file, host, host_key, |
184eed6a | 682 | file_key, &host_line); |
1e3b8b07 | 683 | if (host_status == HOST_NEW) { |
684 | host_file = system_hostfile; | |
f49bc4f7 | 685 | host_status = check_host_in_hostfile(host_file, host, host_key, |
686 | file_key, &host_line); | |
1e3b8b07 | 687 | } |
aa3378df | 688 | /* |
689 | * Also perform check for the ip address, skip the check if we are | |
690 | * localhost or the hostname was an ip address to begin with | |
691 | */ | |
7c49df64 | 692 | if (options.check_host_ip) { |
4fe2af09 | 693 | Key *ip_key = key_new(host_key->type); |
5260325f | 694 | |
1e3b8b07 | 695 | ip_file = user_hostfile; |
f49bc4f7 | 696 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, |
697 | ip_key, &ip_line); | |
1e3b8b07 | 698 | if (ip_status == HOST_NEW) { |
699 | ip_file = system_hostfile; | |
f49bc4f7 | 700 | ip_status = check_host_in_hostfile(ip_file, ip, |
701 | host_key, ip_key, &ip_line); | |
1e3b8b07 | 702 | } |
5260325f | 703 | if (host_status == HOST_CHANGED && |
4fe2af09 | 704 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) |
5260325f | 705 | host_ip_differ = 1; |
706 | ||
4fe2af09 | 707 | key_free(ip_key); |
5260325f | 708 | } else |
709 | ip_status = host_status; | |
710 | ||
4fe2af09 | 711 | key_free(file_key); |
5260325f | 712 | |
713 | switch (host_status) { | |
714 | case HOST_OK: | |
715 | /* The host is known and the key matches. */ | |
1d1ffb87 | 716 | debug("Host '%.200s' is known and matches the %s host key.", |
717 | host, type); | |
1e3b8b07 | 718 | debug("Found key in %s:%d", host_file, host_line); |
7c49df64 | 719 | if (options.check_host_ip && ip_status == HOST_NEW) { |
f49bc4f7 | 720 | if (readonly) |
bbe88b6d | 721 | logit("%s host key for IP address " |
f49bc4f7 | 722 | "'%.128s' not in list of known hosts.", |
7c49df64 | 723 | type, ip); |
f49bc4f7 | 724 | else if (!add_host_to_hostfile(user_hostfile, ip, |
5c63c2ab | 725 | host_key, options.hash_known_hosts)) |
bbe88b6d | 726 | logit("Failed to add the %s host key for IP " |
f49bc4f7 | 727 | "address '%.128s' to the list of known " |
728 | "hosts (%.30s).", type, ip, user_hostfile); | |
729 | else | |
bbe88b6d | 730 | logit("Warning: Permanently added the %s host " |
f49bc4f7 | 731 | "key for IP address '%.128s' to the list " |
732 | "of known hosts.", type, ip); | |
7b3999b8 | 733 | } else if (options.visual_host_key) { |
aff73c5f | 734 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); |
735 | ra = key_fingerprint(host_key, SSH_FP_MD5, | |
736 | SSH_FP_RANDOMART); | |
737 | logit("Host key fingerprint is %s\n%s\n", fp, ra); | |
738 | xfree(ra); | |
739 | xfree(fp); | |
5260325f | 740 | } |
741 | break; | |
742 | case HOST_NEW: | |
331c3884 | 743 | if (options.host_key_alias == NULL && port != 0 && |
744 | port != SSH_DEFAULT_PORT) { | |
745 | debug("checking without port identifier"); | |
96a00a9d | 746 | if (check_host_key(hostname, hostaddr, 0, host_key, |
747 | ROQUIET, user_hostfile, system_hostfile) == 0) { | |
331c3884 | 748 | debug("found matching key w/out port"); |
749 | break; | |
750 | } | |
751 | } | |
f49bc4f7 | 752 | if (readonly) |
753 | goto fail; | |
5260325f | 754 | /* The host is new. */ |
755 | if (options.strict_host_key_checking == 1) { | |
f49bc4f7 | 756 | /* |
757 | * User has requested strict host key checking. We | |
758 | * will not add the host key automatically. The only | |
759 | * alternative left is to abort. | |
760 | */ | |
761 | error("No %s host key is known for %.200s and you " | |
762 | "have requested strict checking.", type, host); | |
763 | goto fail; | |
5260325f | 764 | } else if (options.strict_host_key_checking == 2) { |
1432b5c4 | 765 | char msg1[1024], msg2[1024]; |
766 | ||
767 | if (show_other_keys(host, host_key)) | |
768 | snprintf(msg1, sizeof(msg1), | |
4e2e5cfd | 769 | "\nbut keys of different type are already" |
770 | " known for this host."); | |
1432b5c4 | 771 | else |
772 | snprintf(msg1, sizeof(msg1), "."); | |
5260325f | 773 | /* The default */ |
22138a36 | 774 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); |
aff73c5f | 775 | ra = key_fingerprint(host_key, SSH_FP_MD5, |
776 | SSH_FP_RANDOMART); | |
1432b5c4 | 777 | msg2[0] = '\0'; |
1432b5c4 | 778 | if (options.verify_host_key_dns) { |
0161a13d | 779 | if (matching_host_key_dns) |
1432b5c4 | 780 | snprintf(msg2, sizeof(msg2), |
781 | "Matching host key fingerprint" | |
782 | " found in DNS.\n"); | |
783 | else | |
784 | snprintf(msg2, sizeof(msg2), | |
785 | "No matching host key fingerprint" | |
786 | " found in DNS.\n"); | |
787 | } | |
616a6b93 | 788 | snprintf(msg, sizeof(msg), |
f49bc4f7 | 789 | "The authenticity of host '%.200s (%s)' can't be " |
8a48a7ef | 790 | "established%s\n" |
7b3999b8 | 791 | "%s key fingerprint is %s.%s%s\n%s" |
f49bc4f7 | 792 | "Are you sure you want to continue connecting " |
8a48a7ef | 793 | "(yes/no)? ", |
7b3999b8 | 794 | host, ip, msg1, type, fp, |
795 | options.visual_host_key ? "\n" : "", | |
796 | options.visual_host_key ? ra : "", | |
797 | msg2); | |
aff73c5f | 798 | xfree(ra); |
22138a36 | 799 | xfree(fp); |
616a6b93 | 800 | if (!confirm(msg)) |
f49bc4f7 | 801 | goto fail; |
5260325f | 802 | } |
f49bc4f7 | 803 | /* |
804 | * If not in strict mode, add the key automatically to the | |
805 | * local known_hosts file. | |
806 | */ | |
e79276c2 | 807 | if (options.check_host_ip && ip_status == HOST_NEW) { |
808 | snprintf(hostline, sizeof(hostline), "%s,%s", | |
809 | host, ip); | |
810 | hostp = hostline; | |
811 | if (options.hash_known_hosts) { | |
812 | /* Add hash of host and IP separately */ | |
813 | r = add_host_to_hostfile(user_hostfile, host, | |
814 | host_key, options.hash_known_hosts) && | |
815 | add_host_to_hostfile(user_hostfile, ip, | |
816 | host_key, options.hash_known_hosts); | |
817 | } else { | |
818 | /* Add unhashed "host,ip" */ | |
819 | r = add_host_to_hostfile(user_hostfile, | |
820 | hostline, host_key, | |
821 | options.hash_known_hosts); | |
822 | } | |
823 | } else { | |
824 | r = add_host_to_hostfile(user_hostfile, host, host_key, | |
825 | options.hash_known_hosts); | |
826 | hostp = host; | |
827 | } | |
828 | ||
829 | if (!r) | |
bbe88b6d | 830 | logit("Failed to add the host to the list of known " |
f49bc4f7 | 831 | "hosts (%.500s).", user_hostfile); |
5260325f | 832 | else |
bbe88b6d | 833 | logit("Warning: Permanently added '%.200s' (%s) to the " |
f49bc4f7 | 834 | "list of known hosts.", hostp, type); |
5260325f | 835 | break; |
836 | case HOST_CHANGED: | |
331c3884 | 837 | if (readonly == ROQUIET) |
838 | goto fail; | |
5260325f | 839 | if (options.check_host_ip && host_ip_differ) { |
ca75d7de | 840 | char *key_msg; |
5260325f | 841 | if (ip_status == HOST_NEW) |
ca75d7de | 842 | key_msg = "is unknown"; |
5260325f | 843 | else if (ip_status == HOST_OK) |
ca75d7de | 844 | key_msg = "is unchanged"; |
5260325f | 845 | else |
ca75d7de | 846 | key_msg = "has a different value"; |
5260325f | 847 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
848 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
849 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1d1ffb87 | 850 | error("The %s host key for %s has changed,", type, host); |
6d8216ff | 851 | error("and the key for the corresponding IP address %s", ip); |
ca75d7de | 852 | error("%s. This could either mean that", key_msg); |
5260325f | 853 | error("DNS SPOOFING is happening or the IP address for the host"); |
1e3b8b07 | 854 | error("and its host key have changed at the same time."); |
7c49df64 | 855 | if (ip_status != HOST_NEW) |
1e3b8b07 | 856 | error("Offending key for IP in %s:%d", ip_file, ip_line); |
5260325f | 857 | } |
858 | /* The host key has changed. */ | |
1a1bc5d5 | 859 | warn_changed_key(host_key); |
5260325f | 860 | error("Add correct host key in %.100s to get rid of this message.", |
8abcdba4 | 861 | user_hostfile); |
1e3b8b07 | 862 | error("Offending key in %s:%d", host_file, host_line); |
5260325f | 863 | |
aa3378df | 864 | /* |
865 | * If strict host key checking is in use, the user will have | |
866 | * to edit the key manually and we can only abort. | |
867 | */ | |
f49bc4f7 | 868 | if (options.strict_host_key_checking) { |
869 | error("%s host key for %.200s has changed and you have " | |
870 | "requested strict checking.", type, host); | |
871 | goto fail; | |
872 | } | |
5260325f | 873 | |
aa3378df | 874 | /* |
875 | * If strict host key checking has not been requested, allow | |
d453a600 | 876 | * the connection but without MITM-able authentication or |
fee76795 | 877 | * forwarding. |
aa3378df | 878 | */ |
5260325f | 879 | if (options.password_authentication) { |
f49bc4f7 | 880 | error("Password authentication is disabled to avoid " |
881 | "man-in-the-middle attacks."); | |
5260325f | 882 | options.password_authentication = 0; |
979b31ed | 883 | cancelled_forwarding = 1; |
5260325f | 884 | } |
d453a600 | 885 | if (options.kbd_interactive_authentication) { |
886 | error("Keyboard-interactive authentication is disabled" | |
887 | " to avoid man-in-the-middle attacks."); | |
888 | options.kbd_interactive_authentication = 0; | |
889 | options.challenge_response_authentication = 0; | |
979b31ed | 890 | cancelled_forwarding = 1; |
d453a600 | 891 | } |
892 | if (options.challenge_response_authentication) { | |
893 | error("Challenge/response authentication is disabled" | |
894 | " to avoid man-in-the-middle attacks."); | |
895 | options.challenge_response_authentication = 0; | |
979b31ed | 896 | cancelled_forwarding = 1; |
d453a600 | 897 | } |
5260325f | 898 | if (options.forward_agent) { |
f49bc4f7 | 899 | error("Agent forwarding is disabled to avoid " |
900 | "man-in-the-middle attacks."); | |
5260325f | 901 | options.forward_agent = 0; |
979b31ed | 902 | cancelled_forwarding = 1; |
5260325f | 903 | } |
0b6fbf03 | 904 | if (options.forward_x11) { |
f49bc4f7 | 905 | error("X11 forwarding is disabled to avoid " |
906 | "man-in-the-middle attacks."); | |
0b6fbf03 | 907 | options.forward_x11 = 0; |
979b31ed | 908 | cancelled_forwarding = 1; |
0b6fbf03 | 909 | } |
f49bc4f7 | 910 | if (options.num_local_forwards > 0 || |
911 | options.num_remote_forwards > 0) { | |
912 | error("Port forwarding is disabled to avoid " | |
913 | "man-in-the-middle attacks."); | |
914 | options.num_local_forwards = | |
184eed6a | 915 | options.num_remote_forwards = 0; |
979b31ed | 916 | cancelled_forwarding = 1; |
0b6fbf03 | 917 | } |
fee76795 | 918 | if (options.tun_open != SSH_TUNMODE_NO) { |
919 | error("Tunnel forwarding is disabled to avoid " | |
920 | "man-in-the-middle attacks."); | |
921 | options.tun_open = SSH_TUNMODE_NO; | |
979b31ed | 922 | cancelled_forwarding = 1; |
fee76795 | 923 | } |
979b31ed | 924 | if (options.exit_on_forward_failure && cancelled_forwarding) |
925 | fatal("Error: forwarding disabled due to host key " | |
926 | "check failure"); | |
927 | ||
aa3378df | 928 | /* |
929 | * XXX Should permit the user to change to use the new id. | |
930 | * This could be done by converting the host key to an | |
931 | * identifying sentence, tell that the host identifies itself | |
52e1856c | 932 | * by that sentence, and ask the user if he/she wishes to |
aa3378df | 933 | * accept the authentication. |
934 | */ | |
5260325f | 935 | break; |
8a48a7ef | 936 | case HOST_FOUND: |
937 | fatal("internal error"); | |
938 | break; | |
5260325f | 939 | } |
0b6fbf03 | 940 | |
7c49df64 | 941 | if (options.check_host_ip && host_status != HOST_CHANGED && |
942 | ip_status == HOST_CHANGED) { | |
616a6b93 | 943 | snprintf(msg, sizeof(msg), |
944 | "Warning: the %s host key for '%.200s' " | |
945 | "differs from the key for the IP address '%.128s'" | |
946 | "\nOffending key for IP in %s:%d", | |
947 | type, host, ip, ip_file, ip_line); | |
948 | if (host_status == HOST_OK) { | |
949 | len = strlen(msg); | |
950 | snprintf(msg + len, sizeof(msg) - len, | |
951 | "\nMatching host key in %s:%d", | |
7203d6bb | 952 | host_file, host_line); |
616a6b93 | 953 | } |
7c49df64 | 954 | if (options.strict_host_key_checking == 1) { |
b0545fe6 | 955 | logit("%s", msg); |
f49bc4f7 | 956 | error("Exiting, you have requested strict checking."); |
957 | goto fail; | |
7c49df64 | 958 | } else if (options.strict_host_key_checking == 2) { |
616a6b93 | 959 | strlcat(msg, "\nAre you sure you want " |
960 | "to continue connecting (yes/no)? ", sizeof(msg)); | |
961 | if (!confirm(msg)) | |
f49bc4f7 | 962 | goto fail; |
616a6b93 | 963 | } else { |
b0545fe6 | 964 | logit("%s", msg); |
7c49df64 | 965 | } |
966 | } | |
967 | ||
0b6fbf03 | 968 | xfree(ip); |
d4530052 | 969 | xfree(host); |
f49bc4f7 | 970 | return 0; |
971 | ||
972 | fail: | |
973 | xfree(ip); | |
d4530052 | 974 | xfree(host); |
f49bc4f7 | 975 | return -1; |
976 | } | |
977 | ||
21289cd0 | 978 | /* returns 0 if key verifies or -1 if key does NOT verify */ |
f49bc4f7 | 979 | int |
980 | verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) | |
981 | { | |
982 | struct stat st; | |
0161a13d | 983 | int flags = 0; |
f49bc4f7 | 984 | |
0161a13d | 985 | if (options.verify_host_key_dns && |
986 | verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) { | |
987 | ||
988 | if (flags & DNS_VERIFY_FOUND) { | |
989 | ||
990 | if (options.verify_host_key_dns == 1 && | |
991 | flags & DNS_VERIFY_MATCH && | |
992 | flags & DNS_VERIFY_SECURE) | |
993 | return 0; | |
994 | ||
995 | if (flags & DNS_VERIFY_MATCH) { | |
996 | matching_host_key_dns = 1; | |
997 | } else { | |
998 | warn_changed_key(host_key); | |
999 | error("Update the SSHFP RR in DNS with the new " | |
1000 | "host key to get rid of this message."); | |
1001 | } | |
21289cd0 | 1002 | } |
1003 | } | |
21289cd0 | 1004 | |
f49bc4f7 | 1005 | /* return ok if the key can be found in an old keyfile */ |
1006 | if (stat(options.system_hostfile2, &st) == 0 || | |
1007 | stat(options.user_hostfile2, &st) == 0) { | |
331c3884 | 1008 | if (check_host_key(host, hostaddr, options.port, host_key, |
1009 | RDONLY, options.user_hostfile2, | |
1010 | options.system_hostfile2) == 0) | |
f49bc4f7 | 1011 | return 0; |
1012 | } | |
331c3884 | 1013 | return check_host_key(host, hostaddr, options.port, host_key, |
1014 | RDRW, options.user_hostfile, options.system_hostfile); | |
95f1eccc | 1015 | } |
1016 | ||
8ce64345 | 1017 | /* |
a306f2dd | 1018 | * Starts a dialog with the server, and authenticates the current user on the |
1019 | * server. This does not need any extra privileges. The basic connection | |
1020 | * to the server must already have been established before this is called. | |
1021 | * If login fails, this function prints an error and never returns. | |
1022 | * This function does not require super-user privileges. | |
8ce64345 | 1023 | */ |
1024 | void | |
39c00dc2 | 1025 | ssh_login(Sensitive *sensitive, const char *orighost, |
71300a43 | 1026 | struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms) |
8ce64345 | 1027 | { |
a306f2dd | 1028 | char *host, *cp; |
8ce64345 | 1029 | char *server_user, *local_user; |
8ce64345 | 1030 | |
8ce64345 | 1031 | local_user = xstrdup(pw->pw_name); |
1032 | server_user = options.user ? options.user : local_user; | |
1033 | ||
7b2ea3a1 | 1034 | /* Convert the user-supplied hostname into all lowercase. */ |
1035 | host = xstrdup(orighost); | |
1036 | for (cp = host; *cp; cp++) | |
1037 | if (isupper(*cp)) | |
9555d258 | 1038 | *cp = (char)tolower(*cp); |
7b2ea3a1 | 1039 | |
1040 | /* Exchange protocol version identification strings with the server. */ | |
71300a43 | 1041 | ssh_exchange_identification(timeout_ms); |
7b2ea3a1 | 1042 | |
1043 | /* Put the connection into non-blocking mode. */ | |
1044 | packet_set_nonblocking(); | |
1045 | ||
7b2ea3a1 | 1046 | /* key exchange */ |
7b2ea3a1 | 1047 | /* authenticate user */ |
8ce64345 | 1048 | if (compat20) { |
1049 | ssh_kex2(host, hostaddr); | |
39c00dc2 | 1050 | ssh_userauth2(local_user, server_user, host, sensitive); |
8ce64345 | 1051 | } else { |
8ce64345 | 1052 | ssh_kex(host, hostaddr); |
39c00dc2 | 1053 | ssh_userauth1(local_user, server_user, host, sensitive); |
8ce64345 | 1054 | } |
2b8dc5e3 | 1055 | xfree(local_user); |
7b2ea3a1 | 1056 | } |
0ae4fe1d | 1057 | |
1058 | void | |
1059 | ssh_put_password(char *password) | |
1060 | { | |
1061 | int size; | |
1062 | char *padded; | |
1063 | ||
99c415db | 1064 | if (datafellows & SSH_BUG_PASSWORDPAD) { |
449c5ba5 | 1065 | packet_put_cstring(password); |
99c415db | 1066 | return; |
1067 | } | |
0ae4fe1d | 1068 | size = roundup(strlen(password) + 1, 32); |
52e3daed | 1069 | padded = xcalloc(1, size); |
0ae4fe1d | 1070 | strlcpy(padded, password, size); |
1071 | packet_put_string(padded, size); | |
1072 | memset(padded, 0, size); | |
1073 | xfree(padded); | |
1074 | } | |
8a48a7ef | 1075 | |
1076 | static int | |
1077 | show_key_from_file(const char *file, const char *host, int keytype) | |
1078 | { | |
1079 | Key *found; | |
aff73c5f | 1080 | char *fp, *ra; |
8a48a7ef | 1081 | int line, ret; |
1082 | ||
1083 | found = key_new(keytype); | |
1084 | if ((ret = lookup_key_in_hostfile_by_type(file, host, | |
1085 | keytype, found, &line))) { | |
1086 | fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX); | |
aff73c5f | 1087 | ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART); |
bbe88b6d | 1088 | logit("WARNING: %s key found for host %s\n" |
567a05bf | 1089 | "in %s:%d\n" |
aff73c5f | 1090 | "%s key fingerprint %s.\n%s\n", |
8a48a7ef | 1091 | key_type(found), host, file, line, |
aff73c5f | 1092 | key_type(found), fp, ra); |
1093 | xfree(ra); | |
8a48a7ef | 1094 | xfree(fp); |
1095 | } | |
1096 | key_free(found); | |
1097 | return (ret); | |
1098 | } | |
1099 | ||
1100 | /* print all known host keys for a given host, but skip keys of given type */ | |
1101 | static int | |
1102 | show_other_keys(const char *host, Key *key) | |
1103 | { | |
1104 | int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1}; | |
1105 | int i, found = 0; | |
1106 | ||
1107 | for (i = 0; type[i] != -1; i++) { | |
1108 | if (type[i] == key->type) | |
1109 | continue; | |
1110 | if (type[i] != KEY_RSA1 && | |
1111 | show_key_from_file(options.user_hostfile2, host, type[i])) { | |
1112 | found = 1; | |
1113 | continue; | |
1114 | } | |
1115 | if (type[i] != KEY_RSA1 && | |
1116 | show_key_from_file(options.system_hostfile2, host, type[i])) { | |
1117 | found = 1; | |
1118 | continue; | |
1119 | } | |
1120 | if (show_key_from_file(options.user_hostfile, host, type[i])) { | |
1121 | found = 1; | |
1122 | continue; | |
1123 | } | |
1124 | if (show_key_from_file(options.system_hostfile, host, type[i])) { | |
1125 | found = 1; | |
1126 | continue; | |
1127 | } | |
1128 | debug2("no key of type %d for host %s", type[i], host); | |
1129 | } | |
1130 | return (found); | |
1131 | } | |
1a1bc5d5 | 1132 | |
1133 | static void | |
1134 | warn_changed_key(Key *host_key) | |
1135 | { | |
1136 | char *fp; | |
f5da7f70 | 1137 | const char *type = key_type(host_key); |
1a1bc5d5 | 1138 | |
1139 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); | |
1140 | ||
1141 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1142 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); | |
1143 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1144 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1145 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1146 | error("It is also possible that the %s host key has just been changed.", type); | |
1147 | error("The fingerprint for the %s key sent by the remote host is\n%s.", | |
1148 | type, fp); | |
1149 | error("Please contact your system administrator."); | |
1150 | ||
1151 | xfree(fp); | |
1a1bc5d5 | 1152 | } |
d20f3c9e | 1153 | |
1154 | /* | |
1155 | * Execute a local command | |
1156 | */ | |
1157 | int | |
1158 | ssh_local_cmd(const char *args) | |
1159 | { | |
1160 | char *shell; | |
1161 | pid_t pid; | |
1162 | int status; | |
1163 | ||
1164 | if (!options.permit_local_command || | |
1165 | args == NULL || !*args) | |
1166 | return (1); | |
1167 | ||
1168 | if ((shell = getenv("SHELL")) == NULL) | |
1169 | shell = _PATH_BSHELL; | |
1170 | ||
1171 | pid = fork(); | |
1172 | if (pid == 0) { | |
1173 | debug3("Executing %s -c \"%s\"", shell, args); | |
1174 | execl(shell, shell, "-c", args, (char *)NULL); | |
1175 | error("Couldn't execute %s -c \"%s\": %s", | |
1176 | shell, args, strerror(errno)); | |
1177 | _exit(1); | |
1178 | } else if (pid == -1) | |
1179 | fatal("fork failed: %.100s", strerror(errno)); | |
1180 | while (waitpid(pid, &status, 0) == -1) | |
1181 | if (errno != EINTR) | |
1182 | fatal("Couldn't wait for child: %s", strerror(errno)); | |
1183 | ||
1184 | if (!WIFEXITED(status)) | |
1185 | return (1); | |
1186 | ||
1187 | return (WEXITSTATUS(status)); | |
1188 | } |