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96a00a9d | 1 | /* $OpenBSD: sshconnect.c,v 1.212 2008/10/14 18:11:33 stevesk 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> |
28cb0a43 | 31 | #include <netdb.h> |
b5b88c19 | 32 | #ifdef HAVE_PATHS_H |
a75f5360 | 33 | #include <paths.h> |
b5b88c19 | 34 | #endif |
b1842393 | 35 | #include <pwd.h> |
24436b92 | 36 | #include <stdarg.h> |
cf851879 | 37 | #include <stdio.h> |
ffa517a8 | 38 | #include <stdlib.h> |
00146caa | 39 | #include <string.h> |
5188ba17 | 40 | #include <unistd.h> |
8efc0c15 | 41 | |
8efc0c15 | 42 | #include "xmalloc.h" |
31652869 | 43 | #include "key.h" |
44 | #include "hostfile.h" | |
45 | #include "ssh.h" | |
8efc0c15 | 46 | #include "rsa.h" |
8ce64345 | 47 | #include "buffer.h" |
8efc0c15 | 48 | #include "packet.h" |
8efc0c15 | 49 | #include "uidswap.h" |
50 | #include "compat.h" | |
4fe2af09 | 51 | #include "key.h" |
a306f2dd | 52 | #include "sshconnect.h" |
4fe2af09 | 53 | #include "hostfile.h" |
42f11eb2 | 54 | #include "log.h" |
55 | #include "readconf.h" | |
56 | #include "atomicio.h" | |
57 | #include "misc.h" | |
21289cd0 | 58 | #include "dns.h" |
28015df4 | 59 | #include "version.h" |
21289cd0 | 60 | |
a306f2dd | 61 | char *client_version_string = NULL; |
62 | char *server_version_string = NULL; | |
8ce64345 | 63 | |
ed82a2a9 | 64 | static int matching_host_key_dns = 0; |
1432b5c4 | 65 | |
3fb156df | 66 | /* import */ |
57112b5a | 67 | extern Options options; |
48e671d5 | 68 | extern char *__progname; |
3fb156df | 69 | extern uid_t original_real_uid; |
70 | extern uid_t original_effective_uid; | |
6939bbd4 | 71 | extern pid_t proxy_command_pid; |
57112b5a | 72 | |
8a48a7ef | 73 | static int show_other_keys(const char *, Key *); |
1a1bc5d5 | 74 | static void warn_changed_key(Key *); |
8a48a7ef | 75 | |
5260325f | 76 | /* |
77 | * Connect to the given ssh server using a proxy command. | |
78 | */ | |
396c147e | 79 | static int |
3fb156df | 80 | ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) |
8efc0c15 | 81 | { |
a980cbd7 | 82 | char *command_string, *tmp; |
5260325f | 83 | int pin[2], pout[2]; |
9da5c3c9 | 84 | pid_t pid; |
3af8ef1e | 85 | char *shell, strport[NI_MAXSERV]; |
86 | ||
87 | if ((shell = getenv("SHELL")) == NULL) | |
88 | shell = _PATH_BSHELL; | |
5260325f | 89 | |
90 | /* Convert the port number into a string. */ | |
48e671d5 | 91 | snprintf(strport, sizeof strport, "%hu", port); |
5260325f | 92 | |
6939bbd4 | 93 | /* |
94 | * Build the final command string in the buffer by making the | |
95 | * appropriate substitutions to the given proxy command. | |
96 | * | |
aff51935 | 97 | * Use "exec" to avoid "sh -c" processes on some platforms |
6939bbd4 | 98 | * (e.g. Solaris) |
99 | */ | |
52e3daed | 100 | xasprintf(&tmp, "exec %s", proxy_command); |
a980cbd7 | 101 | command_string = percent_expand(tmp, "h", host, |
102 | "p", strport, (char *)NULL); | |
103 | xfree(tmp); | |
5260325f | 104 | |
105 | /* Create pipes for communicating with the proxy. */ | |
106 | if (pipe(pin) < 0 || pipe(pout) < 0) | |
107 | fatal("Could not create pipes to communicate with the proxy: %.100s", | |
184eed6a | 108 | strerror(errno)); |
5260325f | 109 | |
110 | debug("Executing proxy command: %.500s", command_string); | |
111 | ||
112 | /* Fork and execute the proxy command. */ | |
113 | if ((pid = fork()) == 0) { | |
114 | char *argv[10]; | |
115 | ||
116 | /* Child. Permanently give up superuser privileges. */ | |
3c33c1b6 | 117 | permanently_drop_suid(original_real_uid); |
5260325f | 118 | |
119 | /* Redirect stdin and stdout. */ | |
120 | close(pin[1]); | |
121 | if (pin[0] != 0) { | |
122 | if (dup2(pin[0], 0) < 0) | |
123 | perror("dup2 stdin"); | |
124 | close(pin[0]); | |
125 | } | |
126 | close(pout[0]); | |
127 | if (dup2(pout[1], 1) < 0) | |
128 | perror("dup2 stdout"); | |
129 | /* Cannot be 1 because pin allocated two descriptors. */ | |
130 | close(pout[1]); | |
131 | ||
132 | /* Stderr is left as it is so that error messages get | |
133 | printed on the user's terminal. */ | |
3af8ef1e | 134 | argv[0] = shell; |
5260325f | 135 | argv[1] = "-c"; |
136 | argv[2] = command_string; | |
137 | argv[3] = NULL; | |
138 | ||
139 | /* Execute the proxy command. Note that we gave up any | |
140 | extra privileges above. */ | |
328654d8 | 141 | execv(argv[0], argv); |
142 | perror(argv[0]); | |
5260325f | 143 | exit(1); |
8efc0c15 | 144 | } |
5260325f | 145 | /* Parent. */ |
146 | if (pid < 0) | |
147 | fatal("fork failed: %.100s", strerror(errno)); | |
6939bbd4 | 148 | else |
149 | proxy_command_pid = pid; /* save pid to clean up later */ | |
5260325f | 150 | |
151 | /* Close child side of the descriptors. */ | |
152 | close(pin[0]); | |
153 | close(pout[1]); | |
154 | ||
155 | /* Free the command name. */ | |
a980cbd7 | 156 | xfree(command_string); |
5260325f | 157 | |
158 | /* Set the connection file descriptors. */ | |
159 | packet_set_connection(pout[0], pin[1]); | |
bc2d97c8 | 160 | packet_set_timeout(options.server_alive_interval, |
161 | options.server_alive_count_max); | |
8efc0c15 | 162 | |
ce773142 | 163 | /* Indicate OK return */ |
164 | return 0; | |
5260325f | 165 | } |
8efc0c15 | 166 | |
5260325f | 167 | /* |
168 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
169 | */ | |
396c147e | 170 | static int |
3e131a6d | 171 | ssh_create_socket(int privileged, struct addrinfo *ai) |
8efc0c15 | 172 | { |
3435f5a6 | 173 | int sock, gaierr; |
174 | struct addrinfo hints, *res; | |
5260325f | 175 | |
aa3378df | 176 | /* |
177 | * If we are running as root and want to connect to a privileged | |
178 | * port, bind our own socket to a privileged port. | |
179 | */ | |
5260325f | 180 | if (privileged) { |
181 | int p = IPPORT_RESERVED - 1; | |
3fb156df | 182 | PRIV_START; |
3e131a6d | 183 | sock = rresvport_af(&p, ai->ai_family); |
3fb156df | 184 | PRIV_END; |
5260325f | 185 | if (sock < 0) |
3e131a6d | 186 | error("rresvport: af=%d %.100s", ai->ai_family, |
187 | strerror(errno)); | |
c8d54615 | 188 | else |
189 | debug("Allocated local port %d.", p); | |
3435f5a6 | 190 | return sock; |
191 | } | |
3e131a6d | 192 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); |
3435f5a6 | 193 | if (sock < 0) |
194 | error("socket: %.100s", strerror(errno)); | |
3435f5a6 | 195 | |
196 | /* Bind the socket to an alternative local IP address */ | |
197 | if (options.bind_address == NULL) | |
198 | return sock; | |
199 | ||
200 | memset(&hints, 0, sizeof(hints)); | |
3e131a6d | 201 | hints.ai_family = ai->ai_family; |
202 | hints.ai_socktype = ai->ai_socktype; | |
203 | hints.ai_protocol = ai->ai_protocol; | |
3435f5a6 | 204 | hints.ai_flags = AI_PASSIVE; |
c5daf22b | 205 | gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res); |
3435f5a6 | 206 | if (gaierr) { |
207 | error("getaddrinfo: %s: %s", options.bind_address, | |
bb4626fe | 208 | ssh_gai_strerror(gaierr)); |
3435f5a6 | 209 | close(sock); |
210 | return -1; | |
211 | } | |
212 | if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { | |
213 | error("bind: %s: %s", options.bind_address, strerror(errno)); | |
214 | close(sock); | |
215 | freeaddrinfo(res); | |
216 | return -1; | |
5260325f | 217 | } |
3435f5a6 | 218 | freeaddrinfo(res); |
5260325f | 219 | return sock; |
8efc0c15 | 220 | } |
221 | ||
09ab3296 | 222 | static int |
223 | timeout_connect(int sockfd, const struct sockaddr *serv_addr, | |
71300a43 | 224 | socklen_t addrlen, int *timeoutp) |
09ab3296 | 225 | { |
226 | fd_set *fdset; | |
71300a43 | 227 | struct timeval tv, t_start; |
09ab3296 | 228 | socklen_t optlen; |
52e3daed | 229 | int optval, rc, result = -1; |
09ab3296 | 230 | |
71300a43 | 231 | gettimeofday(&t_start, NULL); |
232 | ||
233 | if (*timeoutp <= 0) { | |
234 | result = connect(sockfd, serv_addr, addrlen); | |
235 | goto done; | |
236 | } | |
09ab3296 | 237 | |
2daf1db1 | 238 | set_nonblock(sockfd); |
09ab3296 | 239 | rc = connect(sockfd, serv_addr, addrlen); |
2daf1db1 | 240 | if (rc == 0) { |
241 | unset_nonblock(sockfd); | |
71300a43 | 242 | result = 0; |
243 | goto done; | |
244 | } | |
245 | if (errno != EINPROGRESS) { | |
246 | result = -1; | |
247 | goto done; | |
2daf1db1 | 248 | } |
09ab3296 | 249 | |
52e3daed | 250 | fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS), |
251 | sizeof(fd_mask)); | |
09ab3296 | 252 | FD_SET(sockfd, fdset); |
71300a43 | 253 | ms_to_timeval(&tv, *timeoutp); |
09ab3296 | 254 | |
f8cc7664 | 255 | for (;;) { |
09ab3296 | 256 | rc = select(sockfd + 1, NULL, fdset, NULL, &tv); |
257 | if (rc != -1 || errno != EINTR) | |
258 | break; | |
259 | } | |
260 | ||
f8cc7664 | 261 | switch (rc) { |
09ab3296 | 262 | case 0: |
263 | /* Timed out */ | |
264 | errno = ETIMEDOUT; | |
da54f5be | 265 | break; |
09ab3296 | 266 | case -1: |
267 | /* Select error */ | |
aff51935 | 268 | debug("select: %s", strerror(errno)); |
da54f5be | 269 | break; |
09ab3296 | 270 | case 1: |
271 | /* Completed or failed */ | |
272 | optval = 0; | |
273 | optlen = sizeof(optval); | |
aff51935 | 274 | if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, |
ce26c02a | 275 | &optlen) == -1) { |
aff51935 | 276 | debug("getsockopt: %s", strerror(errno)); |
da54f5be | 277 | break; |
ce26c02a | 278 | } |
09ab3296 | 279 | if (optval != 0) { |
280 | errno = optval; | |
da54f5be | 281 | break; |
09ab3296 | 282 | } |
da54f5be | 283 | result = 0; |
2daf1db1 | 284 | unset_nonblock(sockfd); |
09ab3296 | 285 | break; |
286 | default: | |
287 | /* Should not occur */ | |
288 | fatal("Bogus return (%d) from select()", rc); | |
289 | } | |
290 | ||
da54f5be | 291 | xfree(fdset); |
71300a43 | 292 | |
293 | done: | |
294 | if (result == 0 && *timeoutp > 0) { | |
295 | ms_subtract_diff(&t_start, timeoutp); | |
296 | if (*timeoutp <= 0) { | |
297 | errno = ETIMEDOUT; | |
298 | result = -1; | |
299 | } | |
300 | } | |
301 | ||
da54f5be | 302 | return (result); |
09ab3296 | 303 | } |
304 | ||
5260325f | 305 | /* |
48e671d5 | 306 | * Opens a TCP/IP connection to the remote server on the given host. |
307 | * The address of the remote host will be returned in hostaddr. | |
3fb156df | 308 | * If port is 0, the default port will be used. If needpriv is true, |
5260325f | 309 | * a privileged port will be allocated to make the connection. |
3fb156df | 310 | * This requires super-user privileges if needpriv is true. |
5260325f | 311 | * Connection_attempts specifies the maximum number of tries (one per |
312 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
313 | * and %p substituted for host and port, respectively) to use to contact | |
314 | * the daemon. | |
315 | */ | |
316 | int | |
48e671d5 | 317 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
71300a43 | 318 | u_short port, int family, int connection_attempts, int *timeout_ms, |
319 | int want_keepalive, int needpriv, const char *proxy_command) | |
8efc0c15 | 320 | { |
b5c334cc | 321 | int gaierr; |
322 | int on = 1; | |
48e671d5 | 323 | int sock = -1, attempt; |
48e671d5 | 324 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; |
b5c334cc | 325 | struct addrinfo hints, *ai, *aitop; |
5260325f | 326 | |
a77673cc | 327 | debug2("ssh_connect: needpriv %d", needpriv); |
5260325f | 328 | |
5260325f | 329 | /* If a proxy command is given, connect using it. */ |
330 | if (proxy_command != NULL) | |
3fb156df | 331 | return ssh_proxy_connect(host, port, proxy_command); |
5260325f | 332 | |
333 | /* No proxy command. */ | |
334 | ||
48e671d5 | 335 | memset(&hints, 0, sizeof(hints)); |
dab89049 | 336 | hints.ai_family = family; |
48e671d5 | 337 | hints.ai_socktype = SOCK_STREAM; |
d6133f43 | 338 | snprintf(strport, sizeof strport, "%u", port); |
48e671d5 | 339 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) |
bb4626fe | 340 | fatal("%s: Could not resolve hostname %.100s: %s", __progname, |
341 | host, ssh_gai_strerror(gaierr)); | |
5260325f | 342 | |
4439dde1 | 343 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
77903f77 | 344 | if (attempt > 0) { |
345 | /* Sleep a moment before retrying. */ | |
346 | sleep(1); | |
5260325f | 347 | debug("Trying again..."); |
77903f77 | 348 | } |
4439dde1 | 349 | /* |
350 | * Loop through addresses for this host, and try each one in | |
351 | * sequence until the connection succeeds. | |
352 | */ | |
48e671d5 | 353 | for (ai = aitop; ai; ai = ai->ai_next) { |
354 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
355 | continue; | |
356 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
357 | ntop, sizeof(ntop), strport, sizeof(strport), | |
358 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
359 | error("ssh_connect: getnameinfo failed"); | |
360 | continue; | |
361 | } | |
362 | debug("Connecting to %.200s [%.100s] port %s.", | |
363 | host, ntop, strport); | |
364 | ||
365 | /* Create a socket for connecting. */ | |
3e131a6d | 366 | sock = ssh_create_socket(needpriv, ai); |
48e671d5 | 367 | if (sock < 0) |
ce773142 | 368 | /* Any error is already output */ |
48e671d5 | 369 | continue; |
370 | ||
09ab3296 | 371 | if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, |
71300a43 | 372 | timeout_ms) >= 0) { |
48e671d5 | 373 | /* Successful connection. */ |
cd332296 | 374 | memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); |
5260325f | 375 | break; |
48e671d5 | 376 | } else { |
c750d869 | 377 | debug("connect to address %s port %s: %s", |
378 | ntop, strport, strerror(errno)); | |
5260325f | 379 | close(sock); |
4439dde1 | 380 | sock = -1; |
5260325f | 381 | } |
8efc0c15 | 382 | } |
4439dde1 | 383 | if (sock != -1) |
48e671d5 | 384 | break; /* Successful connection. */ |
5260325f | 385 | } |
48e671d5 | 386 | |
387 | freeaddrinfo(aitop); | |
388 | ||
5260325f | 389 | /* Return failure if we didn't get a successful connection. */ |
4439dde1 | 390 | if (sock == -1) { |
cf039bd1 | 391 | error("ssh: connect to host %s port %s: %s", |
9bd68577 | 392 | host, strport, strerror(errno)); |
cf039bd1 | 393 | return (-1); |
9bd68577 | 394 | } |
8efc0c15 | 395 | |
5260325f | 396 | debug("Connection established."); |
8efc0c15 | 397 | |
fd573618 | 398 | /* Set SO_KEEPALIVE if requested. */ |
71300a43 | 399 | if (want_keepalive && |
b5c334cc | 400 | setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, |
401 | sizeof(on)) < 0) | |
402 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
8efc0c15 | 403 | |
5260325f | 404 | /* Set the connection. */ |
405 | packet_set_connection(sock, sock); | |
bc2d97c8 | 406 | packet_set_timeout(options.server_alive_interval, |
407 | options.server_alive_count_max); | |
8efc0c15 | 408 | |
ce773142 | 409 | return 0; |
8efc0c15 | 410 | } |
411 | ||
5260325f | 412 | /* |
413 | * Waits for the server identification string, and sends our own | |
414 | * identification string. | |
415 | */ | |
396c147e | 416 | static void |
71300a43 | 417 | ssh_exchange_identification(int timeout_ms) |
8efc0c15 | 418 | { |
5260325f | 419 | char buf[256], remote_version[256]; /* must be same size! */ |
2ceb8101 | 420 | int remote_major, remote_minor, mismatch; |
5260325f | 421 | int connection_in = packet_get_connection_in(); |
422 | int connection_out = packet_get_connection_out(); | |
2b87da3b | 423 | int minor1 = PROTOCOL_MINOR_1; |
e5c76324 | 424 | u_int i, n; |
71300a43 | 425 | size_t len; |
426 | int fdsetsz, remaining, rc; | |
427 | struct timeval t_start, t_remaining; | |
428 | fd_set *fdset; | |
429 | ||
430 | fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask); | |
431 | fdset = xcalloc(1, fdsetsz); | |
5260325f | 432 | |
05624c18 | 433 | /* Read other side's version identification. */ |
71300a43 | 434 | remaining = timeout_ms; |
e5c76324 | 435 | for (n = 0;;) { |
38c295d6 | 436 | for (i = 0; i < sizeof(buf) - 1; i++) { |
71300a43 | 437 | if (timeout_ms > 0) { |
438 | gettimeofday(&t_start, NULL); | |
439 | ms_to_timeval(&t_remaining, remaining); | |
440 | FD_SET(connection_in, fdset); | |
441 | rc = select(connection_in + 1, fdset, NULL, | |
442 | fdset, &t_remaining); | |
443 | ms_subtract_diff(&t_start, &remaining); | |
444 | if (rc == 0 || remaining <= 0) | |
445 | fatal("Connection timed out during " | |
446 | "banner exchange"); | |
447 | if (rc == -1) { | |
448 | if (errno == EINTR) | |
449 | continue; | |
450 | fatal("ssh_exchange_identification: " | |
451 | "select: %s", strerror(errno)); | |
452 | } | |
453 | } | |
454 | ||
455 | len = atomicio(read, connection_in, &buf[i], 1); | |
05624c18 | 456 | |
56964485 | 457 | if (len != 1 && errno == EPIPE) |
71300a43 | 458 | fatal("ssh_exchange_identification: " |
459 | "Connection closed by remote host"); | |
05624c18 | 460 | else if (len != 1) |
71300a43 | 461 | fatal("ssh_exchange_identification: " |
462 | "read: %.100s", strerror(errno)); | |
38c295d6 | 463 | if (buf[i] == '\r') { |
464 | buf[i] = '\n'; | |
465 | buf[i + 1] = 0; | |
466 | continue; /**XXX wait for \n */ | |
467 | } | |
468 | if (buf[i] == '\n') { | |
469 | buf[i + 1] = 0; | |
470 | break; | |
471 | } | |
e5c76324 | 472 | if (++n > 65536) |
71300a43 | 473 | fatal("ssh_exchange_identification: " |
474 | "No banner received"); | |
5260325f | 475 | } |
38c295d6 | 476 | buf[sizeof(buf) - 1] = 0; |
477 | if (strncmp(buf, "SSH-", 4) == 0) | |
5260325f | 478 | break; |
38c295d6 | 479 | debug("ssh_exchange_identification: %s", buf); |
8efc0c15 | 480 | } |
8ce64345 | 481 | server_version_string = xstrdup(buf); |
71300a43 | 482 | xfree(fdset); |
5260325f | 483 | |
aa3378df | 484 | /* |
485 | * Check that the versions match. In future this might accept | |
486 | * several versions and set appropriate flags to handle them. | |
487 | */ | |
8ce64345 | 488 | if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", |
489 | &remote_major, &remote_minor, remote_version) != 3) | |
5260325f | 490 | fatal("Bad remote protocol version identification: '%.100s'", buf); |
491 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
184eed6a | 492 | remote_major, remote_minor, remote_version); |
5260325f | 493 | |
8ce64345 | 494 | compat_datafellows(remote_version); |
a8be9f80 | 495 | mismatch = 0; |
496 | ||
6aacefa7 | 497 | switch (remote_major) { |
a8be9f80 | 498 | case 1: |
499 | if (remote_minor == 99 && | |
500 | (options.protocol & SSH_PROTO_2) && | |
501 | !(options.protocol & SSH_PROTO_1_PREFERRED)) { | |
502 | enable_compat20(); | |
503 | break; | |
5260325f | 504 | } |
a8be9f80 | 505 | if (!(options.protocol & SSH_PROTO_1)) { |
506 | mismatch = 1; | |
507 | break; | |
508 | } | |
509 | if (remote_minor < 3) { | |
510 | fatal("Remote machine has too old SSH software version."); | |
fa08c86b | 511 | } else if (remote_minor == 3 || remote_minor == 4) { |
a8be9f80 | 512 | /* We speak 1.3, too. */ |
513 | enable_compat13(); | |
fa08c86b | 514 | minor1 = 3; |
a8be9f80 | 515 | if (options.forward_agent) { |
bbe88b6d | 516 | logit("Agent forwarding disabled for protocol 1.3"); |
a8be9f80 | 517 | options.forward_agent = 0; |
518 | } | |
519 | } | |
520 | break; | |
521 | case 2: | |
522 | if (options.protocol & SSH_PROTO_2) { | |
523 | enable_compat20(); | |
524 | break; | |
525 | } | |
526 | /* FALLTHROUGH */ | |
6ae2364d | 527 | default: |
a8be9f80 | 528 | mismatch = 1; |
529 | break; | |
8efc0c15 | 530 | } |
a8be9f80 | 531 | if (mismatch) |
5260325f | 532 | fatal("Protocol major versions differ: %d vs. %d", |
a8be9f80 | 533 | (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
534 | remote_major); | |
5260325f | 535 | /* Send our own protocol version identification. */ |
f9b45eaf | 536 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", |
a8be9f80 | 537 | compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
fa08c86b | 538 | compat20 ? PROTOCOL_MINOR_2 : minor1, |
f9b45eaf | 539 | SSH_VERSION, compat20 ? "\r\n" : "\n"); |
dc54438a | 540 | if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf)) |
5260325f | 541 | fatal("write: %.100s", strerror(errno)); |
8ce64345 | 542 | client_version_string = xstrdup(buf); |
543 | chop(client_version_string); | |
544 | chop(server_version_string); | |
545 | debug("Local version string %.100s", client_version_string); | |
8efc0c15 | 546 | } |
547 | ||
f21032a6 | 548 | /* defaults to 'no' */ |
396c147e | 549 | static int |
a2c92c4a | 550 | confirm(const char *prompt) |
8efc0c15 | 551 | { |
616a6b93 | 552 | const char *msg, *again = "Please type 'yes' or 'no': "; |
553 | char *p; | |
554 | int ret = -1; | |
5260325f | 555 | |
f21032a6 | 556 | if (options.batch_mode) |
557 | return 0; | |
616a6b93 | 558 | for (msg = prompt;;msg = again) { |
559 | p = read_passphrase(msg, RP_ECHO); | |
560 | if (p == NULL || | |
561 | (p[0] == '\0') || (p[0] == '\n') || | |
562 | strncasecmp(p, "no", 2) == 0) | |
563 | ret = 0; | |
f11fe301 | 564 | if (p && strncasecmp(p, "yes", 3) == 0) |
616a6b93 | 565 | ret = 1; |
566 | if (p) | |
567 | xfree(p); | |
568 | if (ret != -1) | |
569 | return ret; | |
8efc0c15 | 570 | } |
8efc0c15 | 571 | } |
572 | ||
5260325f | 573 | /* |
f49bc4f7 | 574 | * check whether the supplied host key is valid, return -1 if the key |
575 | * is not valid. the user_hostfile will not be updated if 'readonly' is true. | |
5260325f | 576 | */ |
331c3884 | 577 | #define RDRW 0 |
578 | #define RDONLY 1 | |
579 | #define ROQUIET 2 | |
396c147e | 580 | static int |
331c3884 | 581 | check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, |
582 | Key *host_key, int readonly, const char *user_hostfile, | |
583 | const char *system_hostfile) | |
8efc0c15 | 584 | { |
4fe2af09 | 585 | Key *file_key; |
b6c7b7b7 | 586 | const char *type = key_type(host_key); |
d4530052 | 587 | char *ip = NULL, *host = NULL; |
aff73c5f | 588 | char hostline[1000], *hostp, *fp, *ra; |
5260325f | 589 | HostStatus host_status; |
590 | HostStatus ip_status; | |
e79276c2 | 591 | int r, local = 0, host_ip_differ = 0; |
20af321f | 592 | int salen; |
48e671d5 | 593 | char ntop[NI_MAXHOST]; |
616a6b93 | 594 | char msg[1024]; |
979b31ed | 595 | int len, host_line, ip_line, cancelled_forwarding = 0; |
1e3b8b07 | 596 | const char *host_file = NULL, *ip_file = NULL; |
48e671d5 | 597 | |
598 | /* | |
599 | * Force accepting of the host key for loopback/localhost. The | |
600 | * problem is that if the home directory is NFS-mounted to multiple | |
601 | * machines, localhost will refer to a different machine in each of | |
602 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
603 | * essentially disables host authentication for localhost; however, | |
604 | * this is probably not a real problem. | |
605 | */ | |
a306f2dd | 606 | /** hostaddr == 0! */ |
48e671d5 | 607 | switch (hostaddr->sa_family) { |
608 | case AF_INET: | |
f49bc4f7 | 609 | local = (ntohl(((struct sockaddr_in *)hostaddr)-> |
4e2e5cfd | 610 | sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; |
20af321f | 611 | salen = sizeof(struct sockaddr_in); |
48e671d5 | 612 | break; |
613 | case AF_INET6: | |
f49bc4f7 | 614 | local = IN6_IS_ADDR_LOOPBACK( |
615 | &(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
20af321f | 616 | salen = sizeof(struct sockaddr_in6); |
48e671d5 | 617 | break; |
618 | default: | |
619 | local = 0; | |
20af321f | 620 | salen = sizeof(struct sockaddr_storage); |
48e671d5 | 621 | break; |
622 | } | |
8bbc048a | 623 | if (options.no_host_authentication_for_localhost == 1 && local && |
624 | options.host_key_alias == NULL) { | |
7c49df64 | 625 | debug("Forcing accepting of host key for " |
626 | "loopback/localhost."); | |
f49bc4f7 | 627 | return 0; |
48e671d5 | 628 | } |
5260325f | 629 | |
57112b5a | 630 | /* |
7c49df64 | 631 | * We don't have the remote ip-address for connections |
632 | * using a proxy command | |
633 | */ | |
634 | if (options.proxy_command == NULL) { | |
635 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), | |
636 | NULL, 0, NI_NUMERICHOST) != 0) | |
637 | fatal("check_host_key: getnameinfo failed"); | |
331c3884 | 638 | ip = put_host_port(ntop, port); |
7c49df64 | 639 | } else { |
640 | ip = xstrdup("<no hostip for proxy command>"); | |
641 | } | |
e907df41 | 642 | |
7c49df64 | 643 | /* |
644 | * Turn off check_host_ip if the connection is to localhost, via proxy | |
645 | * command or if we don't have a hostname to compare with | |
57112b5a | 646 | */ |
d4530052 | 647 | if (options.check_host_ip && (local || |
648 | strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) | |
57112b5a | 649 | options.check_host_ip = 0; |
650 | ||
8abcdba4 | 651 | /* |
d4530052 | 652 | * Allow the user to record the key under a different name or |
653 | * differentiate a non-standard port. This is useful for ssh | |
654 | * tunneling over forwarded connections or if you run multiple | |
655 | * sshd's on different ports on the same machine. | |
8abcdba4 | 656 | */ |
657 | if (options.host_key_alias != NULL) { | |
d4530052 | 658 | host = xstrdup(options.host_key_alias); |
8abcdba4 | 659 | debug("using hostkeyalias: %s", host); |
d4530052 | 660 | } else { |
331c3884 | 661 | host = put_host_port(hostname, port); |
8abcdba4 | 662 | } |
663 | ||
95f1eccc | 664 | /* |
665 | * Store the host key from the known host file in here so that we can | |
666 | * compare it with the key for the IP address. | |
667 | */ | |
4fe2af09 | 668 | file_key = key_new(host_key->type); |
5260325f | 669 | |
aa3378df | 670 | /* |
7b9b0103 | 671 | * Check if the host key is present in the user's list of known |
aa3378df | 672 | * hosts or in the systemwide list. |
673 | */ | |
1e3b8b07 | 674 | host_file = user_hostfile; |
f49bc4f7 | 675 | host_status = check_host_in_hostfile(host_file, host, host_key, |
184eed6a | 676 | file_key, &host_line); |
1e3b8b07 | 677 | if (host_status == HOST_NEW) { |
678 | host_file = system_hostfile; | |
f49bc4f7 | 679 | host_status = check_host_in_hostfile(host_file, host, host_key, |
680 | file_key, &host_line); | |
1e3b8b07 | 681 | } |
aa3378df | 682 | /* |
683 | * Also perform check for the ip address, skip the check if we are | |
684 | * localhost or the hostname was an ip address to begin with | |
685 | */ | |
7c49df64 | 686 | if (options.check_host_ip) { |
4fe2af09 | 687 | Key *ip_key = key_new(host_key->type); |
5260325f | 688 | |
1e3b8b07 | 689 | ip_file = user_hostfile; |
f49bc4f7 | 690 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, |
691 | ip_key, &ip_line); | |
1e3b8b07 | 692 | if (ip_status == HOST_NEW) { |
693 | ip_file = system_hostfile; | |
f49bc4f7 | 694 | ip_status = check_host_in_hostfile(ip_file, ip, |
695 | host_key, ip_key, &ip_line); | |
1e3b8b07 | 696 | } |
5260325f | 697 | if (host_status == HOST_CHANGED && |
4fe2af09 | 698 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) |
5260325f | 699 | host_ip_differ = 1; |
700 | ||
4fe2af09 | 701 | key_free(ip_key); |
5260325f | 702 | } else |
703 | ip_status = host_status; | |
704 | ||
4fe2af09 | 705 | key_free(file_key); |
5260325f | 706 | |
707 | switch (host_status) { | |
708 | case HOST_OK: | |
709 | /* The host is known and the key matches. */ | |
1d1ffb87 | 710 | debug("Host '%.200s' is known and matches the %s host key.", |
711 | host, type); | |
1e3b8b07 | 712 | debug("Found key in %s:%d", host_file, host_line); |
7c49df64 | 713 | if (options.check_host_ip && ip_status == HOST_NEW) { |
f49bc4f7 | 714 | if (readonly) |
bbe88b6d | 715 | logit("%s host key for IP address " |
f49bc4f7 | 716 | "'%.128s' not in list of known hosts.", |
7c49df64 | 717 | type, ip); |
f49bc4f7 | 718 | else if (!add_host_to_hostfile(user_hostfile, ip, |
5c63c2ab | 719 | host_key, options.hash_known_hosts)) |
bbe88b6d | 720 | logit("Failed to add the %s host key for IP " |
f49bc4f7 | 721 | "address '%.128s' to the list of known " |
722 | "hosts (%.30s).", type, ip, user_hostfile); | |
723 | else | |
bbe88b6d | 724 | logit("Warning: Permanently added the %s host " |
f49bc4f7 | 725 | "key for IP address '%.128s' to the list " |
726 | "of known hosts.", type, ip); | |
7b3999b8 | 727 | } else if (options.visual_host_key) { |
aff73c5f | 728 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); |
729 | ra = key_fingerprint(host_key, SSH_FP_MD5, | |
730 | SSH_FP_RANDOMART); | |
731 | logit("Host key fingerprint is %s\n%s\n", fp, ra); | |
732 | xfree(ra); | |
733 | xfree(fp); | |
5260325f | 734 | } |
735 | break; | |
736 | case HOST_NEW: | |
331c3884 | 737 | if (options.host_key_alias == NULL && port != 0 && |
738 | port != SSH_DEFAULT_PORT) { | |
739 | debug("checking without port identifier"); | |
96a00a9d | 740 | if (check_host_key(hostname, hostaddr, 0, host_key, |
741 | ROQUIET, user_hostfile, system_hostfile) == 0) { | |
331c3884 | 742 | debug("found matching key w/out port"); |
743 | break; | |
744 | } | |
745 | } | |
f49bc4f7 | 746 | if (readonly) |
747 | goto fail; | |
5260325f | 748 | /* The host is new. */ |
749 | if (options.strict_host_key_checking == 1) { | |
f49bc4f7 | 750 | /* |
751 | * User has requested strict host key checking. We | |
752 | * will not add the host key automatically. The only | |
753 | * alternative left is to abort. | |
754 | */ | |
755 | error("No %s host key is known for %.200s and you " | |
756 | "have requested strict checking.", type, host); | |
757 | goto fail; | |
5260325f | 758 | } else if (options.strict_host_key_checking == 2) { |
1432b5c4 | 759 | char msg1[1024], msg2[1024]; |
760 | ||
761 | if (show_other_keys(host, host_key)) | |
762 | snprintf(msg1, sizeof(msg1), | |
4e2e5cfd | 763 | "\nbut keys of different type are already" |
764 | " known for this host."); | |
1432b5c4 | 765 | else |
766 | snprintf(msg1, sizeof(msg1), "."); | |
5260325f | 767 | /* The default */ |
22138a36 | 768 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); |
aff73c5f | 769 | ra = key_fingerprint(host_key, SSH_FP_MD5, |
770 | SSH_FP_RANDOMART); | |
1432b5c4 | 771 | msg2[0] = '\0'; |
1432b5c4 | 772 | if (options.verify_host_key_dns) { |
0161a13d | 773 | if (matching_host_key_dns) |
1432b5c4 | 774 | snprintf(msg2, sizeof(msg2), |
775 | "Matching host key fingerprint" | |
776 | " found in DNS.\n"); | |
777 | else | |
778 | snprintf(msg2, sizeof(msg2), | |
779 | "No matching host key fingerprint" | |
780 | " found in DNS.\n"); | |
781 | } | |
616a6b93 | 782 | snprintf(msg, sizeof(msg), |
f49bc4f7 | 783 | "The authenticity of host '%.200s (%s)' can't be " |
8a48a7ef | 784 | "established%s\n" |
7b3999b8 | 785 | "%s key fingerprint is %s.%s%s\n%s" |
f49bc4f7 | 786 | "Are you sure you want to continue connecting " |
8a48a7ef | 787 | "(yes/no)? ", |
7b3999b8 | 788 | host, ip, msg1, type, fp, |
789 | options.visual_host_key ? "\n" : "", | |
790 | options.visual_host_key ? ra : "", | |
791 | msg2); | |
aff73c5f | 792 | xfree(ra); |
22138a36 | 793 | xfree(fp); |
616a6b93 | 794 | if (!confirm(msg)) |
f49bc4f7 | 795 | goto fail; |
5260325f | 796 | } |
f49bc4f7 | 797 | /* |
798 | * If not in strict mode, add the key automatically to the | |
799 | * local known_hosts file. | |
800 | */ | |
e79276c2 | 801 | if (options.check_host_ip && ip_status == HOST_NEW) { |
802 | snprintf(hostline, sizeof(hostline), "%s,%s", | |
803 | host, ip); | |
804 | hostp = hostline; | |
805 | if (options.hash_known_hosts) { | |
806 | /* Add hash of host and IP separately */ | |
807 | r = add_host_to_hostfile(user_hostfile, host, | |
808 | host_key, options.hash_known_hosts) && | |
809 | add_host_to_hostfile(user_hostfile, ip, | |
810 | host_key, options.hash_known_hosts); | |
811 | } else { | |
812 | /* Add unhashed "host,ip" */ | |
813 | r = add_host_to_hostfile(user_hostfile, | |
814 | hostline, host_key, | |
815 | options.hash_known_hosts); | |
816 | } | |
817 | } else { | |
818 | r = add_host_to_hostfile(user_hostfile, host, host_key, | |
819 | options.hash_known_hosts); | |
820 | hostp = host; | |
821 | } | |
822 | ||
823 | if (!r) | |
bbe88b6d | 824 | logit("Failed to add the host to the list of known " |
f49bc4f7 | 825 | "hosts (%.500s).", user_hostfile); |
5260325f | 826 | else |
bbe88b6d | 827 | logit("Warning: Permanently added '%.200s' (%s) to the " |
f49bc4f7 | 828 | "list of known hosts.", hostp, type); |
5260325f | 829 | break; |
830 | case HOST_CHANGED: | |
331c3884 | 831 | if (readonly == ROQUIET) |
832 | goto fail; | |
5260325f | 833 | if (options.check_host_ip && host_ip_differ) { |
ca75d7de | 834 | char *key_msg; |
5260325f | 835 | if (ip_status == HOST_NEW) |
ca75d7de | 836 | key_msg = "is unknown"; |
5260325f | 837 | else if (ip_status == HOST_OK) |
ca75d7de | 838 | key_msg = "is unchanged"; |
5260325f | 839 | else |
ca75d7de | 840 | key_msg = "has a different value"; |
5260325f | 841 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
842 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
843 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1d1ffb87 | 844 | error("The %s host key for %s has changed,", type, host); |
6d8216ff | 845 | error("and the key for the corresponding IP address %s", ip); |
ca75d7de | 846 | error("%s. This could either mean that", key_msg); |
5260325f | 847 | error("DNS SPOOFING is happening or the IP address for the host"); |
1e3b8b07 | 848 | error("and its host key have changed at the same time."); |
7c49df64 | 849 | if (ip_status != HOST_NEW) |
1e3b8b07 | 850 | error("Offending key for IP in %s:%d", ip_file, ip_line); |
5260325f | 851 | } |
852 | /* The host key has changed. */ | |
1a1bc5d5 | 853 | warn_changed_key(host_key); |
5260325f | 854 | error("Add correct host key in %.100s to get rid of this message.", |
8abcdba4 | 855 | user_hostfile); |
1e3b8b07 | 856 | error("Offending key in %s:%d", host_file, host_line); |
5260325f | 857 | |
aa3378df | 858 | /* |
859 | * If strict host key checking is in use, the user will have | |
860 | * to edit the key manually and we can only abort. | |
861 | */ | |
f49bc4f7 | 862 | if (options.strict_host_key_checking) { |
863 | error("%s host key for %.200s has changed and you have " | |
864 | "requested strict checking.", type, host); | |
865 | goto fail; | |
866 | } | |
5260325f | 867 | |
aa3378df | 868 | /* |
869 | * If strict host key checking has not been requested, allow | |
d453a600 | 870 | * the connection but without MITM-able authentication or |
fee76795 | 871 | * forwarding. |
aa3378df | 872 | */ |
5260325f | 873 | if (options.password_authentication) { |
f49bc4f7 | 874 | error("Password authentication is disabled to avoid " |
875 | "man-in-the-middle attacks."); | |
5260325f | 876 | options.password_authentication = 0; |
979b31ed | 877 | cancelled_forwarding = 1; |
5260325f | 878 | } |
d453a600 | 879 | if (options.kbd_interactive_authentication) { |
880 | error("Keyboard-interactive authentication is disabled" | |
881 | " to avoid man-in-the-middle attacks."); | |
882 | options.kbd_interactive_authentication = 0; | |
883 | options.challenge_response_authentication = 0; | |
979b31ed | 884 | cancelled_forwarding = 1; |
d453a600 | 885 | } |
886 | if (options.challenge_response_authentication) { | |
887 | error("Challenge/response authentication is disabled" | |
888 | " to avoid man-in-the-middle attacks."); | |
889 | options.challenge_response_authentication = 0; | |
979b31ed | 890 | cancelled_forwarding = 1; |
d453a600 | 891 | } |
5260325f | 892 | if (options.forward_agent) { |
f49bc4f7 | 893 | error("Agent forwarding is disabled to avoid " |
894 | "man-in-the-middle attacks."); | |
5260325f | 895 | options.forward_agent = 0; |
979b31ed | 896 | cancelled_forwarding = 1; |
5260325f | 897 | } |
0b6fbf03 | 898 | if (options.forward_x11) { |
f49bc4f7 | 899 | error("X11 forwarding is disabled to avoid " |
900 | "man-in-the-middle attacks."); | |
0b6fbf03 | 901 | options.forward_x11 = 0; |
979b31ed | 902 | cancelled_forwarding = 1; |
0b6fbf03 | 903 | } |
f49bc4f7 | 904 | if (options.num_local_forwards > 0 || |
905 | options.num_remote_forwards > 0) { | |
906 | error("Port forwarding is disabled to avoid " | |
907 | "man-in-the-middle attacks."); | |
908 | options.num_local_forwards = | |
184eed6a | 909 | options.num_remote_forwards = 0; |
979b31ed | 910 | cancelled_forwarding = 1; |
0b6fbf03 | 911 | } |
fee76795 | 912 | if (options.tun_open != SSH_TUNMODE_NO) { |
913 | error("Tunnel forwarding is disabled to avoid " | |
914 | "man-in-the-middle attacks."); | |
915 | options.tun_open = SSH_TUNMODE_NO; | |
979b31ed | 916 | cancelled_forwarding = 1; |
fee76795 | 917 | } |
979b31ed | 918 | if (options.exit_on_forward_failure && cancelled_forwarding) |
919 | fatal("Error: forwarding disabled due to host key " | |
920 | "check failure"); | |
921 | ||
aa3378df | 922 | /* |
923 | * XXX Should permit the user to change to use the new id. | |
924 | * This could be done by converting the host key to an | |
925 | * identifying sentence, tell that the host identifies itself | |
926 | * by that sentence, and ask the user if he/she whishes to | |
927 | * accept the authentication. | |
928 | */ | |
5260325f | 929 | break; |
8a48a7ef | 930 | case HOST_FOUND: |
931 | fatal("internal error"); | |
932 | break; | |
5260325f | 933 | } |
0b6fbf03 | 934 | |
7c49df64 | 935 | if (options.check_host_ip && host_status != HOST_CHANGED && |
936 | ip_status == HOST_CHANGED) { | |
616a6b93 | 937 | snprintf(msg, sizeof(msg), |
938 | "Warning: the %s host key for '%.200s' " | |
939 | "differs from the key for the IP address '%.128s'" | |
940 | "\nOffending key for IP in %s:%d", | |
941 | type, host, ip, ip_file, ip_line); | |
942 | if (host_status == HOST_OK) { | |
943 | len = strlen(msg); | |
944 | snprintf(msg + len, sizeof(msg) - len, | |
945 | "\nMatching host key in %s:%d", | |
7203d6bb | 946 | host_file, host_line); |
616a6b93 | 947 | } |
7c49df64 | 948 | if (options.strict_host_key_checking == 1) { |
b0545fe6 | 949 | logit("%s", msg); |
f49bc4f7 | 950 | error("Exiting, you have requested strict checking."); |
951 | goto fail; | |
7c49df64 | 952 | } else if (options.strict_host_key_checking == 2) { |
616a6b93 | 953 | strlcat(msg, "\nAre you sure you want " |
954 | "to continue connecting (yes/no)? ", sizeof(msg)); | |
955 | if (!confirm(msg)) | |
f49bc4f7 | 956 | goto fail; |
616a6b93 | 957 | } else { |
b0545fe6 | 958 | logit("%s", msg); |
7c49df64 | 959 | } |
960 | } | |
961 | ||
0b6fbf03 | 962 | xfree(ip); |
d4530052 | 963 | xfree(host); |
f49bc4f7 | 964 | return 0; |
965 | ||
966 | fail: | |
967 | xfree(ip); | |
d4530052 | 968 | xfree(host); |
f49bc4f7 | 969 | return -1; |
970 | } | |
971 | ||
21289cd0 | 972 | /* returns 0 if key verifies or -1 if key does NOT verify */ |
f49bc4f7 | 973 | int |
974 | verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) | |
975 | { | |
976 | struct stat st; | |
0161a13d | 977 | int flags = 0; |
f49bc4f7 | 978 | |
0161a13d | 979 | if (options.verify_host_key_dns && |
980 | verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) { | |
981 | ||
982 | if (flags & DNS_VERIFY_FOUND) { | |
983 | ||
984 | if (options.verify_host_key_dns == 1 && | |
985 | flags & DNS_VERIFY_MATCH && | |
986 | flags & DNS_VERIFY_SECURE) | |
987 | return 0; | |
988 | ||
989 | if (flags & DNS_VERIFY_MATCH) { | |
990 | matching_host_key_dns = 1; | |
991 | } else { | |
992 | warn_changed_key(host_key); | |
993 | error("Update the SSHFP RR in DNS with the new " | |
994 | "host key to get rid of this message."); | |
995 | } | |
21289cd0 | 996 | } |
997 | } | |
21289cd0 | 998 | |
f49bc4f7 | 999 | /* return ok if the key can be found in an old keyfile */ |
1000 | if (stat(options.system_hostfile2, &st) == 0 || | |
1001 | stat(options.user_hostfile2, &st) == 0) { | |
331c3884 | 1002 | if (check_host_key(host, hostaddr, options.port, host_key, |
1003 | RDONLY, options.user_hostfile2, | |
1004 | options.system_hostfile2) == 0) | |
f49bc4f7 | 1005 | return 0; |
1006 | } | |
331c3884 | 1007 | return check_host_key(host, hostaddr, options.port, host_key, |
1008 | RDRW, options.user_hostfile, options.system_hostfile); | |
95f1eccc | 1009 | } |
1010 | ||
8ce64345 | 1011 | /* |
a306f2dd | 1012 | * Starts a dialog with the server, and authenticates the current user on the |
1013 | * server. This does not need any extra privileges. The basic connection | |
1014 | * to the server must already have been established before this is called. | |
1015 | * If login fails, this function prints an error and never returns. | |
1016 | * This function does not require super-user privileges. | |
8ce64345 | 1017 | */ |
1018 | void | |
39c00dc2 | 1019 | ssh_login(Sensitive *sensitive, const char *orighost, |
71300a43 | 1020 | struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms) |
8ce64345 | 1021 | { |
a306f2dd | 1022 | char *host, *cp; |
8ce64345 | 1023 | char *server_user, *local_user; |
8ce64345 | 1024 | |
8ce64345 | 1025 | local_user = xstrdup(pw->pw_name); |
1026 | server_user = options.user ? options.user : local_user; | |
1027 | ||
7b2ea3a1 | 1028 | /* Convert the user-supplied hostname into all lowercase. */ |
1029 | host = xstrdup(orighost); | |
1030 | for (cp = host; *cp; cp++) | |
1031 | if (isupper(*cp)) | |
9555d258 | 1032 | *cp = (char)tolower(*cp); |
7b2ea3a1 | 1033 | |
1034 | /* Exchange protocol version identification strings with the server. */ | |
71300a43 | 1035 | ssh_exchange_identification(timeout_ms); |
7b2ea3a1 | 1036 | |
1037 | /* Put the connection into non-blocking mode. */ | |
1038 | packet_set_nonblocking(); | |
1039 | ||
7b2ea3a1 | 1040 | /* key exchange */ |
7b2ea3a1 | 1041 | /* authenticate user */ |
8ce64345 | 1042 | if (compat20) { |
1043 | ssh_kex2(host, hostaddr); | |
39c00dc2 | 1044 | ssh_userauth2(local_user, server_user, host, sensitive); |
8ce64345 | 1045 | } else { |
8ce64345 | 1046 | ssh_kex(host, hostaddr); |
39c00dc2 | 1047 | ssh_userauth1(local_user, server_user, host, sensitive); |
8ce64345 | 1048 | } |
2b8dc5e3 | 1049 | xfree(local_user); |
7b2ea3a1 | 1050 | } |
0ae4fe1d | 1051 | |
1052 | void | |
1053 | ssh_put_password(char *password) | |
1054 | { | |
1055 | int size; | |
1056 | char *padded; | |
1057 | ||
99c415db | 1058 | if (datafellows & SSH_BUG_PASSWORDPAD) { |
449c5ba5 | 1059 | packet_put_cstring(password); |
99c415db | 1060 | return; |
1061 | } | |
0ae4fe1d | 1062 | size = roundup(strlen(password) + 1, 32); |
52e3daed | 1063 | padded = xcalloc(1, size); |
0ae4fe1d | 1064 | strlcpy(padded, password, size); |
1065 | packet_put_string(padded, size); | |
1066 | memset(padded, 0, size); | |
1067 | xfree(padded); | |
1068 | } | |
8a48a7ef | 1069 | |
1070 | static int | |
1071 | show_key_from_file(const char *file, const char *host, int keytype) | |
1072 | { | |
1073 | Key *found; | |
aff73c5f | 1074 | char *fp, *ra; |
8a48a7ef | 1075 | int line, ret; |
1076 | ||
1077 | found = key_new(keytype); | |
1078 | if ((ret = lookup_key_in_hostfile_by_type(file, host, | |
1079 | keytype, found, &line))) { | |
1080 | fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX); | |
aff73c5f | 1081 | ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART); |
bbe88b6d | 1082 | logit("WARNING: %s key found for host %s\n" |
567a05bf | 1083 | "in %s:%d\n" |
aff73c5f | 1084 | "%s key fingerprint %s.\n%s\n", |
8a48a7ef | 1085 | key_type(found), host, file, line, |
aff73c5f | 1086 | key_type(found), fp, ra); |
1087 | xfree(ra); | |
8a48a7ef | 1088 | xfree(fp); |
1089 | } | |
1090 | key_free(found); | |
1091 | return (ret); | |
1092 | } | |
1093 | ||
1094 | /* print all known host keys for a given host, but skip keys of given type */ | |
1095 | static int | |
1096 | show_other_keys(const char *host, Key *key) | |
1097 | { | |
1098 | int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1}; | |
1099 | int i, found = 0; | |
1100 | ||
1101 | for (i = 0; type[i] != -1; i++) { | |
1102 | if (type[i] == key->type) | |
1103 | continue; | |
1104 | if (type[i] != KEY_RSA1 && | |
1105 | show_key_from_file(options.user_hostfile2, host, type[i])) { | |
1106 | found = 1; | |
1107 | continue; | |
1108 | } | |
1109 | if (type[i] != KEY_RSA1 && | |
1110 | show_key_from_file(options.system_hostfile2, host, type[i])) { | |
1111 | found = 1; | |
1112 | continue; | |
1113 | } | |
1114 | if (show_key_from_file(options.user_hostfile, host, type[i])) { | |
1115 | found = 1; | |
1116 | continue; | |
1117 | } | |
1118 | if (show_key_from_file(options.system_hostfile, host, type[i])) { | |
1119 | found = 1; | |
1120 | continue; | |
1121 | } | |
1122 | debug2("no key of type %d for host %s", type[i], host); | |
1123 | } | |
1124 | return (found); | |
1125 | } | |
1a1bc5d5 | 1126 | |
1127 | static void | |
1128 | warn_changed_key(Key *host_key) | |
1129 | { | |
1130 | char *fp; | |
f5da7f70 | 1131 | const char *type = key_type(host_key); |
1a1bc5d5 | 1132 | |
1133 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); | |
1134 | ||
1135 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1136 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); | |
1137 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1138 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1139 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1140 | error("It is also possible that the %s host key has just been changed.", type); | |
1141 | error("The fingerprint for the %s key sent by the remote host is\n%s.", | |
1142 | type, fp); | |
1143 | error("Please contact your system administrator."); | |
1144 | ||
1145 | xfree(fp); | |
1a1bc5d5 | 1146 | } |
d20f3c9e | 1147 | |
1148 | /* | |
1149 | * Execute a local command | |
1150 | */ | |
1151 | int | |
1152 | ssh_local_cmd(const char *args) | |
1153 | { | |
1154 | char *shell; | |
1155 | pid_t pid; | |
1156 | int status; | |
1157 | ||
1158 | if (!options.permit_local_command || | |
1159 | args == NULL || !*args) | |
1160 | return (1); | |
1161 | ||
1162 | if ((shell = getenv("SHELL")) == NULL) | |
1163 | shell = _PATH_BSHELL; | |
1164 | ||
1165 | pid = fork(); | |
1166 | if (pid == 0) { | |
1167 | debug3("Executing %s -c \"%s\"", shell, args); | |
1168 | execl(shell, shell, "-c", args, (char *)NULL); | |
1169 | error("Couldn't execute %s -c \"%s\": %s", | |
1170 | shell, args, strerror(errno)); | |
1171 | _exit(1); | |
1172 | } else if (pid == -1) | |
1173 | fatal("fork failed: %.100s", strerror(errno)); | |
1174 | while (waitpid(pid, &status, 0) == -1) | |
1175 | if (errno != EINTR) | |
1176 | fatal("Couldn't wait for child: %s", strerror(errno)); | |
1177 | ||
1178 | if (!WIFEXITED(status)) | |
1179 | return (1); | |
1180 | ||
1181 | return (WEXITSTATUS(status)); | |
1182 | } |