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91d9cdd3 | 1 | /* $OpenBSD: sshconnect.c,v 1.212 2008/10/14 18:11:33 stevesk Exp $ */ |
3c0ef626 | 2 | /* |
3 | * Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | * All rights reserved | |
6 | * Code to connect to a remote host, and to perform the client side of the | |
7 | * login (authentication) dialog. | |
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". | |
14 | */ | |
15 | ||
16 | #include "includes.h" | |
3c0ef626 | 17 | |
9108f8d9 | 18 | #include <sys/types.h> |
19 | #include <sys/wait.h> | |
20 | #include <sys/stat.h> | |
21 | #include <sys/socket.h> | |
22 | #ifdef HAVE_SYS_TIME_H | |
23 | # include <sys/time.h> | |
24 | #endif | |
25 | ||
26 | #include <netinet/in.h> | |
27 | #include <arpa/inet.h> | |
28 | ||
29 | #include <ctype.h> | |
30 | #include <errno.h> | |
31 | #include <netdb.h> | |
32 | #ifdef HAVE_PATHS_H | |
33 | #include <paths.h> | |
34 | #endif | |
35 | #include <pwd.h> | |
36 | #include <stdarg.h> | |
37 | #include <stdio.h> | |
38 | #include <stdlib.h> | |
39 | #include <string.h> | |
40 | #include <unistd.h> | |
3c0ef626 | 41 | |
3c0ef626 | 42 | #include "xmalloc.h" |
9108f8d9 | 43 | #include "key.h" |
44 | #include "hostfile.h" | |
45 | #include "ssh.h" | |
3c0ef626 | 46 | #include "rsa.h" |
47 | #include "buffer.h" | |
48 | #include "packet.h" | |
49 | #include "uidswap.h" | |
50 | #include "compat.h" | |
51 | #include "key.h" | |
52 | #include "sshconnect.h" | |
53 | #include "hostfile.h" | |
54 | #include "log.h" | |
55 | #include "readconf.h" | |
56 | #include "atomicio.h" | |
57 | #include "misc.h" | |
0fff78ff | 58 | #include "dns.h" |
9108f8d9 | 59 | #include "version.h" |
0fff78ff | 60 | |
3c0ef626 | 61 | char *client_version_string = NULL; |
62 | char *server_version_string = NULL; | |
63 | ||
2c06c99b | 64 | static int matching_host_key_dns = 0; |
0fff78ff | 65 | |
f5799ae1 | 66 | /* import */ |
3c0ef626 | 67 | extern Options options; |
68 | extern char *__progname; | |
f5799ae1 | 69 | extern uid_t original_real_uid; |
70 | extern uid_t original_effective_uid; | |
41b2f314 | 71 | extern pid_t proxy_command_pid; |
3c0ef626 | 72 | |
41b2f314 | 73 | static int show_other_keys(const char *, Key *); |
cdd66111 | 74 | static void warn_changed_key(Key *); |
3c0ef626 | 75 | |
76 | /* | |
77 | * Connect to the given ssh server using a proxy command. | |
78 | */ | |
79 | static int | |
f5799ae1 | 80 | ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) |
3c0ef626 | 81 | { |
665a873d | 82 | char *command_string, *tmp; |
3c0ef626 | 83 | int pin[2], pout[2]; |
84 | pid_t pid; | |
47686178 | 85 | char *shell, strport[NI_MAXSERV]; |
86 | ||
87 | if ((shell = getenv("SHELL")) == NULL) | |
88 | shell = _PATH_BSHELL; | |
3c0ef626 | 89 | |
90 | /* Convert the port number into a string. */ | |
91 | snprintf(strport, sizeof strport, "%hu", port); | |
92 | ||
41b2f314 | 93 | /* |
94 | * Build the final command string in the buffer by making the | |
95 | * appropriate substitutions to the given proxy command. | |
96 | * | |
cdd66111 | 97 | * Use "exec" to avoid "sh -c" processes on some platforms |
41b2f314 | 98 | * (e.g. Solaris) |
99 | */ | |
9108f8d9 | 100 | xasprintf(&tmp, "exec %s", proxy_command); |
665a873d | 101 | command_string = percent_expand(tmp, "h", host, |
102 | "p", strport, (char *)NULL); | |
103 | xfree(tmp); | |
3c0ef626 | 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", | |
e9a17296 | 108 | strerror(errno)); |
3c0ef626 | 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. */ | |
9108f8d9 | 117 | permanently_drop_suid(original_real_uid); |
3c0ef626 | 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. */ | |
47686178 | 134 | argv[0] = shell; |
3c0ef626 | 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. */ | |
141 | execv(argv[0], argv); | |
142 | perror(argv[0]); | |
143 | exit(1); | |
144 | } | |
145 | /* Parent. */ | |
146 | if (pid < 0) | |
147 | fatal("fork failed: %.100s", strerror(errno)); | |
41b2f314 | 148 | else |
149 | proxy_command_pid = pid; /* save pid to clean up later */ | |
3c0ef626 | 150 | |
151 | /* Close child side of the descriptors. */ | |
152 | close(pin[0]); | |
153 | close(pout[1]); | |
154 | ||
155 | /* Free the command name. */ | |
665a873d | 156 | xfree(command_string); |
3c0ef626 | 157 | |
158 | /* Set the connection file descriptors. */ | |
159 | packet_set_connection(pout[0], pin[1]); | |
22616013 | 160 | packet_set_timeout(options.server_alive_interval, |
161 | options.server_alive_count_max); | |
3c0ef626 | 162 | |
163 | /* Indicate OK return */ | |
164 | return 0; | |
165 | } | |
166 | ||
76d45d2f | 167 | /* |
168 | * Set TCP receive buffer if requested. | |
169 | * Note: tuning needs to happen after the socket is | |
170 | * created but before the connection happens | |
171 | * so winscale is negotiated properly -cjr | |
172 | */ | |
173 | static void | |
174 | ssh_set_socket_recvbuf(int sock) | |
175 | { | |
176 | void *buf = (void *)&options.tcp_rcv_buf; | |
177 | int sz = sizeof(options.tcp_rcv_buf); | |
178 | int socksize; | |
179 | int socksizelen = sizeof(int); | |
180 | ||
181 | debug("setsockopt Attempting to set SO_RCVBUF to %d", options.tcp_rcv_buf); | |
182 | if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF, buf, sz) >= 0) { | |
183 | getsockopt(sock, SOL_SOCKET, SO_RCVBUF, &socksize, &socksizelen); | |
184 | debug("setsockopt SO_RCVBUF: %.100s %d", strerror(errno), socksize); | |
185 | } | |
186 | else | |
187 | error("Couldn't set socket receive buffer to %d: %.100s", | |
188 | options.tcp_rcv_buf, strerror(errno)); | |
189 | } | |
190 | ||
191 | ||
3c0ef626 | 192 | /* |
193 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
194 | */ | |
195 | static int | |
0fff78ff | 196 | ssh_create_socket(int privileged, struct addrinfo *ai) |
3c0ef626 | 197 | { |
198 | int sock, gaierr; | |
199 | struct addrinfo hints, *res; | |
200 | ||
201 | /* | |
202 | * If we are running as root and want to connect to a privileged | |
203 | * port, bind our own socket to a privileged port. | |
204 | */ | |
205 | if (privileged) { | |
206 | int p = IPPORT_RESERVED - 1; | |
f5799ae1 | 207 | PRIV_START; |
0fff78ff | 208 | sock = rresvport_af(&p, ai->ai_family); |
f5799ae1 | 209 | PRIV_END; |
3c0ef626 | 210 | if (sock < 0) |
0fff78ff | 211 | error("rresvport: af=%d %.100s", ai->ai_family, |
212 | strerror(errno)); | |
3c0ef626 | 213 | else |
214 | debug("Allocated local port %d.", p); | |
76d45d2f | 215 | |
216 | if (options.tcp_rcv_buf > 0) | |
217 | ssh_set_socket_recvbuf(sock); | |
3c0ef626 | 218 | return sock; |
219 | } | |
0fff78ff | 220 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); |
3c0ef626 | 221 | if (sock < 0) |
222 | error("socket: %.100s", strerror(errno)); | |
3c0ef626 | 223 | |
76d45d2f | 224 | if (options.tcp_rcv_buf > 0) |
225 | ssh_set_socket_recvbuf(sock); | |
226 | ||
3c0ef626 | 227 | /* Bind the socket to an alternative local IP address */ |
228 | if (options.bind_address == NULL) | |
229 | return sock; | |
230 | ||
231 | memset(&hints, 0, sizeof(hints)); | |
0fff78ff | 232 | hints.ai_family = ai->ai_family; |
233 | hints.ai_socktype = ai->ai_socktype; | |
234 | hints.ai_protocol = ai->ai_protocol; | |
3c0ef626 | 235 | hints.ai_flags = AI_PASSIVE; |
22616013 | 236 | gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res); |
3c0ef626 | 237 | if (gaierr) { |
238 | error("getaddrinfo: %s: %s", options.bind_address, | |
47686178 | 239 | ssh_gai_strerror(gaierr)); |
3c0ef626 | 240 | close(sock); |
241 | return -1; | |
242 | } | |
243 | if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { | |
244 | error("bind: %s: %s", options.bind_address, strerror(errno)); | |
245 | close(sock); | |
246 | freeaddrinfo(res); | |
247 | return -1; | |
248 | } | |
249 | freeaddrinfo(res); | |
250 | return sock; | |
251 | } | |
252 | ||
0fff78ff | 253 | static int |
254 | timeout_connect(int sockfd, const struct sockaddr *serv_addr, | |
47686178 | 255 | socklen_t addrlen, int *timeoutp) |
0fff78ff | 256 | { |
257 | fd_set *fdset; | |
47686178 | 258 | struct timeval tv, t_start; |
0fff78ff | 259 | socklen_t optlen; |
9108f8d9 | 260 | int optval, rc, result = -1; |
0fff78ff | 261 | |
47686178 | 262 | gettimeofday(&t_start, NULL); |
263 | ||
264 | if (*timeoutp <= 0) { | |
265 | result = connect(sockfd, serv_addr, addrlen); | |
266 | goto done; | |
267 | } | |
0fff78ff | 268 | |
cdd66111 | 269 | set_nonblock(sockfd); |
0fff78ff | 270 | rc = connect(sockfd, serv_addr, addrlen); |
cdd66111 | 271 | if (rc == 0) { |
272 | unset_nonblock(sockfd); | |
47686178 | 273 | result = 0; |
274 | goto done; | |
275 | } | |
276 | if (errno != EINPROGRESS) { | |
277 | result = -1; | |
278 | goto done; | |
cdd66111 | 279 | } |
0fff78ff | 280 | |
9108f8d9 | 281 | fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS), |
282 | sizeof(fd_mask)); | |
0fff78ff | 283 | FD_SET(sockfd, fdset); |
47686178 | 284 | ms_to_timeval(&tv, *timeoutp); |
0fff78ff | 285 | |
dec6d9fe | 286 | for (;;) { |
0fff78ff | 287 | rc = select(sockfd + 1, NULL, fdset, NULL, &tv); |
288 | if (rc != -1 || errno != EINTR) | |
289 | break; | |
290 | } | |
291 | ||
dec6d9fe | 292 | switch (rc) { |
0fff78ff | 293 | case 0: |
294 | /* Timed out */ | |
295 | errno = ETIMEDOUT; | |
296 | break; | |
297 | case -1: | |
298 | /* Select error */ | |
cdd66111 | 299 | debug("select: %s", strerror(errno)); |
0fff78ff | 300 | break; |
301 | case 1: | |
302 | /* Completed or failed */ | |
303 | optval = 0; | |
304 | optlen = sizeof(optval); | |
cdd66111 | 305 | if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, |
acc3d05e | 306 | &optlen) == -1) { |
cdd66111 | 307 | debug("getsockopt: %s", strerror(errno)); |
0fff78ff | 308 | break; |
acc3d05e | 309 | } |
0fff78ff | 310 | if (optval != 0) { |
311 | errno = optval; | |
312 | break; | |
313 | } | |
314 | result = 0; | |
cdd66111 | 315 | unset_nonblock(sockfd); |
0fff78ff | 316 | break; |
317 | default: | |
318 | /* Should not occur */ | |
319 | fatal("Bogus return (%d) from select()", rc); | |
320 | } | |
321 | ||
322 | xfree(fdset); | |
47686178 | 323 | |
324 | done: | |
325 | if (result == 0 && *timeoutp > 0) { | |
326 | ms_subtract_diff(&t_start, timeoutp); | |
327 | if (*timeoutp <= 0) { | |
328 | errno = ETIMEDOUT; | |
329 | result = -1; | |
330 | } | |
331 | } | |
332 | ||
0fff78ff | 333 | return (result); |
334 | } | |
335 | ||
3c0ef626 | 336 | /* |
337 | * Opens a TCP/IP connection to the remote server on the given host. | |
338 | * The address of the remote host will be returned in hostaddr. | |
f5799ae1 | 339 | * If port is 0, the default port will be used. If needpriv is true, |
3c0ef626 | 340 | * a privileged port will be allocated to make the connection. |
f5799ae1 | 341 | * This requires super-user privileges if needpriv is true. |
3c0ef626 | 342 | * Connection_attempts specifies the maximum number of tries (one per |
343 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
344 | * and %p substituted for host and port, respectively) to use to contact | |
345 | * the daemon. | |
3c0ef626 | 346 | */ |
347 | int | |
348 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, | |
47686178 | 349 | u_short port, int family, int connection_attempts, int *timeout_ms, |
350 | int want_keepalive, int needpriv, const char *proxy_command) | |
3c0ef626 | 351 | { |
352 | int gaierr; | |
353 | int on = 1; | |
354 | int sock = -1, attempt; | |
355 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
356 | struct addrinfo hints, *ai, *aitop; | |
3c0ef626 | 357 | |
6a9b3198 | 358 | debug2("ssh_connect: needpriv %d", needpriv); |
3c0ef626 | 359 | |
3c0ef626 | 360 | /* If a proxy command is given, connect using it. */ |
361 | if (proxy_command != NULL) | |
f5799ae1 | 362 | return ssh_proxy_connect(host, port, proxy_command); |
3c0ef626 | 363 | |
364 | /* No proxy command. */ | |
365 | ||
366 | memset(&hints, 0, sizeof(hints)); | |
367 | hints.ai_family = family; | |
368 | hints.ai_socktype = SOCK_STREAM; | |
680cee3b | 369 | snprintf(strport, sizeof strport, "%u", port); |
3c0ef626 | 370 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) |
47686178 | 371 | fatal("%s: Could not resolve hostname %.100s: %s", __progname, |
372 | host, ssh_gai_strerror(gaierr)); | |
3c0ef626 | 373 | |
9108f8d9 | 374 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
ff7ec503 | 375 | if (attempt > 0) { |
376 | /* Sleep a moment before retrying. */ | |
377 | sleep(1); | |
3c0ef626 | 378 | debug("Trying again..."); |
ff7ec503 | 379 | } |
9108f8d9 | 380 | /* |
381 | * Loop through addresses for this host, and try each one in | |
382 | * sequence until the connection succeeds. | |
383 | */ | |
3c0ef626 | 384 | for (ai = aitop; ai; ai = ai->ai_next) { |
385 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
386 | continue; | |
387 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
388 | ntop, sizeof(ntop), strport, sizeof(strport), | |
389 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
390 | error("ssh_connect: getnameinfo failed"); | |
391 | continue; | |
392 | } | |
393 | debug("Connecting to %.200s [%.100s] port %s.", | |
394 | host, ntop, strport); | |
395 | ||
396 | /* Create a socket for connecting. */ | |
0fff78ff | 397 | sock = ssh_create_socket(needpriv, ai); |
3c0ef626 | 398 | if (sock < 0) |
399 | /* Any error is already output */ | |
400 | continue; | |
401 | ||
0fff78ff | 402 | if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, |
47686178 | 403 | timeout_ms) >= 0) { |
3c0ef626 | 404 | /* Successful connection. */ |
405 | memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); | |
3c0ef626 | 406 | break; |
407 | } else { | |
41b2f314 | 408 | debug("connect to address %s port %s: %s", |
409 | ntop, strport, strerror(errno)); | |
3c0ef626 | 410 | close(sock); |
9108f8d9 | 411 | sock = -1; |
3c0ef626 | 412 | } |
413 | } | |
9108f8d9 | 414 | if (sock != -1) |
3c0ef626 | 415 | break; /* Successful connection. */ |
3c0ef626 | 416 | } |
417 | ||
418 | freeaddrinfo(aitop); | |
419 | ||
420 | /* Return failure if we didn't get a successful connection. */ | |
9108f8d9 | 421 | if (sock == -1) { |
996d5e62 | 422 | error("ssh: connect to host %s port %s: %s", |
41b2f314 | 423 | host, strport, strerror(errno)); |
996d5e62 | 424 | return (-1); |
41b2f314 | 425 | } |
3c0ef626 | 426 | |
427 | debug("Connection established."); | |
428 | ||
cdd66111 | 429 | /* Set SO_KEEPALIVE if requested. */ |
47686178 | 430 | if (want_keepalive && |
3c0ef626 | 431 | setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, |
432 | sizeof(on)) < 0) | |
433 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
434 | ||
435 | /* Set the connection. */ | |
436 | packet_set_connection(sock, sock); | |
22616013 | 437 | packet_set_timeout(options.server_alive_interval, |
438 | options.server_alive_count_max); | |
3c0ef626 | 439 | |
440 | return 0; | |
441 | } | |
442 | ||
443 | /* | |
444 | * Waits for the server identification string, and sends our own | |
445 | * identification string. | |
446 | */ | |
447 | static void | |
47686178 | 448 | ssh_exchange_identification(int timeout_ms) |
3c0ef626 | 449 | { |
450 | char buf[256], remote_version[256]; /* must be same size! */ | |
665a873d | 451 | int remote_major, remote_minor, mismatch; |
3c0ef626 | 452 | int connection_in = packet_get_connection_in(); |
453 | int connection_out = packet_get_connection_out(); | |
454 | int minor1 = PROTOCOL_MINOR_1; | |
9108f8d9 | 455 | u_int i, n; |
47686178 | 456 | size_t len; |
457 | int fdsetsz, remaining, rc; | |
458 | struct timeval t_start, t_remaining; | |
459 | fd_set *fdset; | |
460 | ||
461 | fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask); | |
462 | fdset = xcalloc(1, fdsetsz); | |
3c0ef626 | 463 | |
665a873d | 464 | /* Read other side's version identification. */ |
47686178 | 465 | remaining = timeout_ms; |
9108f8d9 | 466 | for (n = 0;;) { |
3c0ef626 | 467 | for (i = 0; i < sizeof(buf) - 1; i++) { |
47686178 | 468 | if (timeout_ms > 0) { |
469 | gettimeofday(&t_start, NULL); | |
470 | ms_to_timeval(&t_remaining, remaining); | |
471 | FD_SET(connection_in, fdset); | |
472 | rc = select(connection_in + 1, fdset, NULL, | |
473 | fdset, &t_remaining); | |
474 | ms_subtract_diff(&t_start, &remaining); | |
475 | if (rc == 0 || remaining <= 0) | |
476 | fatal("Connection timed out during " | |
477 | "banner exchange"); | |
478 | if (rc == -1) { | |
479 | if (errno == EINTR) | |
480 | continue; | |
481 | fatal("ssh_exchange_identification: " | |
482 | "select: %s", strerror(errno)); | |
483 | } | |
484 | } | |
485 | ||
486 | len = atomicio(read, connection_in, &buf[i], 1); | |
665a873d | 487 | |
488 | if (len != 1 && errno == EPIPE) | |
47686178 | 489 | fatal("ssh_exchange_identification: " |
490 | "Connection closed by remote host"); | |
665a873d | 491 | else if (len != 1) |
47686178 | 492 | fatal("ssh_exchange_identification: " |
493 | "read: %.100s", strerror(errno)); | |
3c0ef626 | 494 | if (buf[i] == '\r') { |
495 | buf[i] = '\n'; | |
496 | buf[i + 1] = 0; | |
497 | continue; /**XXX wait for \n */ | |
498 | } | |
499 | if (buf[i] == '\n') { | |
500 | buf[i + 1] = 0; | |
501 | break; | |
502 | } | |
9108f8d9 | 503 | if (++n > 65536) |
47686178 | 504 | fatal("ssh_exchange_identification: " |
505 | "No banner received"); | |
3c0ef626 | 506 | } |
507 | buf[sizeof(buf) - 1] = 0; | |
508 | if (strncmp(buf, "SSH-", 4) == 0) | |
509 | break; | |
510 | debug("ssh_exchange_identification: %s", buf); | |
511 | } | |
512 | server_version_string = xstrdup(buf); | |
47686178 | 513 | xfree(fdset); |
3c0ef626 | 514 | |
515 | /* | |
516 | * Check that the versions match. In future this might accept | |
517 | * several versions and set appropriate flags to handle them. | |
518 | */ | |
519 | if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", | |
520 | &remote_major, &remote_minor, remote_version) != 3) | |
521 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
522 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
e9a17296 | 523 | remote_major, remote_minor, remote_version); |
3c0ef626 | 524 | |
525 | compat_datafellows(remote_version); | |
526 | mismatch = 0; | |
527 | ||
e9a17296 | 528 | switch (remote_major) { |
3c0ef626 | 529 | case 1: |
530 | if (remote_minor == 99 && | |
531 | (options.protocol & SSH_PROTO_2) && | |
532 | !(options.protocol & SSH_PROTO_1_PREFERRED)) { | |
533 | enable_compat20(); | |
534 | break; | |
535 | } | |
536 | if (!(options.protocol & SSH_PROTO_1)) { | |
537 | mismatch = 1; | |
538 | break; | |
539 | } | |
540 | if (remote_minor < 3) { | |
541 | fatal("Remote machine has too old SSH software version."); | |
542 | } else if (remote_minor == 3 || remote_minor == 4) { | |
543 | /* We speak 1.3, too. */ | |
544 | enable_compat13(); | |
545 | minor1 = 3; | |
546 | if (options.forward_agent) { | |
0fff78ff | 547 | logit("Agent forwarding disabled for protocol 1.3"); |
3c0ef626 | 548 | options.forward_agent = 0; |
549 | } | |
550 | } | |
551 | break; | |
552 | case 2: | |
553 | if (options.protocol & SSH_PROTO_2) { | |
554 | enable_compat20(); | |
555 | break; | |
556 | } | |
557 | /* FALLTHROUGH */ | |
558 | default: | |
559 | mismatch = 1; | |
560 | break; | |
561 | } | |
562 | if (mismatch) | |
563 | fatal("Protocol major versions differ: %d vs. %d", | |
564 | (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, | |
565 | remote_major); | |
566 | /* Send our own protocol version identification. */ | |
22616013 | 567 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", |
3c0ef626 | 568 | compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
569 | compat20 ? PROTOCOL_MINOR_2 : minor1, | |
76d45d2f | 570 | SSH_RELEASE, compat20 ? "\r\n" : "\n"); |
0fff78ff | 571 | if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf)) |
3c0ef626 | 572 | fatal("write: %.100s", strerror(errno)); |
573 | client_version_string = xstrdup(buf); | |
574 | chop(client_version_string); | |
575 | chop(server_version_string); | |
576 | debug("Local version string %.100s", client_version_string); | |
577 | } | |
578 | ||
579 | /* defaults to 'no' */ | |
580 | static int | |
581 | confirm(const char *prompt) | |
582 | { | |
e9a17296 | 583 | const char *msg, *again = "Please type 'yes' or 'no': "; |
584 | char *p; | |
585 | int ret = -1; | |
3c0ef626 | 586 | |
587 | if (options.batch_mode) | |
588 | return 0; | |
e9a17296 | 589 | for (msg = prompt;;msg = again) { |
590 | p = read_passphrase(msg, RP_ECHO); | |
591 | if (p == NULL || | |
592 | (p[0] == '\0') || (p[0] == '\n') || | |
593 | strncasecmp(p, "no", 2) == 0) | |
594 | ret = 0; | |
41b2f314 | 595 | if (p && strncasecmp(p, "yes", 3) == 0) |
e9a17296 | 596 | ret = 1; |
597 | if (p) | |
598 | xfree(p); | |
599 | if (ret != -1) | |
600 | return ret; | |
3c0ef626 | 601 | } |
602 | } | |
603 | ||
604 | /* | |
605 | * check whether the supplied host key is valid, return -1 if the key | |
606 | * is not valid. the user_hostfile will not be updated if 'readonly' is true. | |
607 | */ | |
9108f8d9 | 608 | #define RDRW 0 |
609 | #define RDONLY 1 | |
610 | #define ROQUIET 2 | |
3c0ef626 | 611 | static int |
9108f8d9 | 612 | check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, |
613 | Key *host_key, int readonly, const char *user_hostfile, | |
614 | const char *system_hostfile) | |
3c0ef626 | 615 | { |
616 | Key *file_key; | |
cdd66111 | 617 | const char *type = key_type(host_key); |
9108f8d9 | 618 | char *ip = NULL, *host = NULL; |
22616013 | 619 | char hostline[1000], *hostp, *fp, *ra; |
3c0ef626 | 620 | HostStatus host_status; |
621 | HostStatus ip_status; | |
996d5e62 | 622 | int r, local = 0, host_ip_differ = 0; |
3c0ef626 | 623 | int salen; |
624 | char ntop[NI_MAXHOST]; | |
e9a17296 | 625 | char msg[1024]; |
22616013 | 626 | int len, host_line, ip_line, cancelled_forwarding = 0; |
3c0ef626 | 627 | const char *host_file = NULL, *ip_file = NULL; |
628 | ||
629 | /* | |
630 | * Force accepting of the host key for loopback/localhost. The | |
631 | * problem is that if the home directory is NFS-mounted to multiple | |
632 | * machines, localhost will refer to a different machine in each of | |
633 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
634 | * essentially disables host authentication for localhost; however, | |
635 | * this is probably not a real problem. | |
636 | */ | |
637 | /** hostaddr == 0! */ | |
638 | switch (hostaddr->sa_family) { | |
639 | case AF_INET: | |
640 | local = (ntohl(((struct sockaddr_in *)hostaddr)-> | |
665a873d | 641 | sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; |
3c0ef626 | 642 | salen = sizeof(struct sockaddr_in); |
643 | break; | |
644 | case AF_INET6: | |
645 | local = IN6_IS_ADDR_LOOPBACK( | |
646 | &(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
647 | salen = sizeof(struct sockaddr_in6); | |
648 | break; | |
649 | default: | |
650 | local = 0; | |
651 | salen = sizeof(struct sockaddr_storage); | |
652 | break; | |
653 | } | |
654 | if (options.no_host_authentication_for_localhost == 1 && local && | |
655 | options.host_key_alias == NULL) { | |
656 | debug("Forcing accepting of host key for " | |
657 | "loopback/localhost."); | |
658 | return 0; | |
659 | } | |
660 | ||
661 | /* | |
662 | * We don't have the remote ip-address for connections | |
663 | * using a proxy command | |
664 | */ | |
665 | if (options.proxy_command == NULL) { | |
666 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), | |
667 | NULL, 0, NI_NUMERICHOST) != 0) | |
668 | fatal("check_host_key: getnameinfo failed"); | |
9108f8d9 | 669 | ip = put_host_port(ntop, port); |
3c0ef626 | 670 | } else { |
671 | ip = xstrdup("<no hostip for proxy command>"); | |
672 | } | |
22616013 | 673 | |
3c0ef626 | 674 | /* |
675 | * Turn off check_host_ip if the connection is to localhost, via proxy | |
676 | * command or if we don't have a hostname to compare with | |
677 | */ | |
9108f8d9 | 678 | if (options.check_host_ip && (local || |
679 | strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) | |
3c0ef626 | 680 | options.check_host_ip = 0; |
681 | ||
682 | /* | |
9108f8d9 | 683 | * Allow the user to record the key under a different name or |
684 | * differentiate a non-standard port. This is useful for ssh | |
685 | * tunneling over forwarded connections or if you run multiple | |
686 | * sshd's on different ports on the same machine. | |
3c0ef626 | 687 | */ |
688 | if (options.host_key_alias != NULL) { | |
9108f8d9 | 689 | host = xstrdup(options.host_key_alias); |
3c0ef626 | 690 | debug("using hostkeyalias: %s", host); |
9108f8d9 | 691 | } else { |
692 | host = put_host_port(hostname, port); | |
3c0ef626 | 693 | } |
694 | ||
695 | /* | |
696 | * Store the host key from the known host file in here so that we can | |
697 | * compare it with the key for the IP address. | |
698 | */ | |
699 | file_key = key_new(host_key->type); | |
700 | ||
701 | /* | |
2c06c99b | 702 | * Check if the host key is present in the user's list of known |
3c0ef626 | 703 | * hosts or in the systemwide list. |
704 | */ | |
705 | host_file = user_hostfile; | |
706 | host_status = check_host_in_hostfile(host_file, host, host_key, | |
e9a17296 | 707 | file_key, &host_line); |
3c0ef626 | 708 | if (host_status == HOST_NEW) { |
709 | host_file = system_hostfile; | |
710 | host_status = check_host_in_hostfile(host_file, host, host_key, | |
711 | file_key, &host_line); | |
712 | } | |
713 | /* | |
714 | * Also perform check for the ip address, skip the check if we are | |
715 | * localhost or the hostname was an ip address to begin with | |
716 | */ | |
717 | if (options.check_host_ip) { | |
718 | Key *ip_key = key_new(host_key->type); | |
719 | ||
720 | ip_file = user_hostfile; | |
721 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, | |
722 | ip_key, &ip_line); | |
723 | if (ip_status == HOST_NEW) { | |
724 | ip_file = system_hostfile; | |
725 | ip_status = check_host_in_hostfile(ip_file, ip, | |
726 | host_key, ip_key, &ip_line); | |
727 | } | |
728 | if (host_status == HOST_CHANGED && | |
729 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) | |
730 | host_ip_differ = 1; | |
731 | ||
732 | key_free(ip_key); | |
733 | } else | |
734 | ip_status = host_status; | |
735 | ||
736 | key_free(file_key); | |
737 | ||
738 | switch (host_status) { | |
739 | case HOST_OK: | |
740 | /* The host is known and the key matches. */ | |
741 | debug("Host '%.200s' is known and matches the %s host key.", | |
742 | host, type); | |
743 | debug("Found key in %s:%d", host_file, host_line); | |
744 | if (options.check_host_ip && ip_status == HOST_NEW) { | |
745 | if (readonly) | |
0fff78ff | 746 | logit("%s host key for IP address " |
3c0ef626 | 747 | "'%.128s' not in list of known hosts.", |
748 | type, ip); | |
749 | else if (!add_host_to_hostfile(user_hostfile, ip, | |
996d5e62 | 750 | host_key, options.hash_known_hosts)) |
0fff78ff | 751 | logit("Failed to add the %s host key for IP " |
3c0ef626 | 752 | "address '%.128s' to the list of known " |
753 | "hosts (%.30s).", type, ip, user_hostfile); | |
754 | else | |
0fff78ff | 755 | logit("Warning: Permanently added the %s host " |
3c0ef626 | 756 | "key for IP address '%.128s' to the list " |
757 | "of known hosts.", type, ip); | |
22616013 | 758 | } else if (options.visual_host_key) { |
759 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); | |
760 | ra = key_fingerprint(host_key, SSH_FP_MD5, | |
761 | SSH_FP_RANDOMART); | |
762 | logit("Host key fingerprint is %s\n%s\n", fp, ra); | |
763 | xfree(ra); | |
764 | xfree(fp); | |
3c0ef626 | 765 | } |
766 | break; | |
767 | case HOST_NEW: | |
9108f8d9 | 768 | if (options.host_key_alias == NULL && port != 0 && |
769 | port != SSH_DEFAULT_PORT) { | |
770 | debug("checking without port identifier"); | |
91d9cdd3 | 771 | if (check_host_key(hostname, hostaddr, 0, host_key, |
772 | ROQUIET, user_hostfile, system_hostfile) == 0) { | |
9108f8d9 | 773 | debug("found matching key w/out port"); |
774 | break; | |
775 | } | |
776 | } | |
3c0ef626 | 777 | if (readonly) |
778 | goto fail; | |
779 | /* The host is new. */ | |
780 | if (options.strict_host_key_checking == 1) { | |
781 | /* | |
782 | * User has requested strict host key checking. We | |
783 | * will not add the host key automatically. The only | |
784 | * alternative left is to abort. | |
785 | */ | |
786 | error("No %s host key is known for %.200s and you " | |
787 | "have requested strict checking.", type, host); | |
788 | goto fail; | |
789 | } else if (options.strict_host_key_checking == 2) { | |
0fff78ff | 790 | char msg1[1024], msg2[1024]; |
791 | ||
792 | if (show_other_keys(host, host_key)) | |
793 | snprintf(msg1, sizeof(msg1), | |
665a873d | 794 | "\nbut keys of different type are already" |
795 | " known for this host."); | |
0fff78ff | 796 | else |
797 | snprintf(msg1, sizeof(msg1), "."); | |
3c0ef626 | 798 | /* The default */ |
3c0ef626 | 799 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); |
22616013 | 800 | ra = key_fingerprint(host_key, SSH_FP_MD5, |
801 | SSH_FP_RANDOMART); | |
0fff78ff | 802 | msg2[0] = '\0'; |
0fff78ff | 803 | if (options.verify_host_key_dns) { |
cdd66111 | 804 | if (matching_host_key_dns) |
0fff78ff | 805 | snprintf(msg2, sizeof(msg2), |
806 | "Matching host key fingerprint" | |
807 | " found in DNS.\n"); | |
808 | else | |
809 | snprintf(msg2, sizeof(msg2), | |
810 | "No matching host key fingerprint" | |
811 | " found in DNS.\n"); | |
812 | } | |
e9a17296 | 813 | snprintf(msg, sizeof(msg), |
3c0ef626 | 814 | "The authenticity of host '%.200s (%s)' can't be " |
41b2f314 | 815 | "established%s\n" |
22616013 | 816 | "%s key fingerprint is %s.%s%s\n%s" |
3c0ef626 | 817 | "Are you sure you want to continue connecting " |
41b2f314 | 818 | "(yes/no)? ", |
22616013 | 819 | host, ip, msg1, type, fp, |
820 | options.visual_host_key ? "\n" : "", | |
821 | options.visual_host_key ? ra : "", | |
822 | msg2); | |
823 | xfree(ra); | |
3c0ef626 | 824 | xfree(fp); |
e9a17296 | 825 | if (!confirm(msg)) |
3c0ef626 | 826 | goto fail; |
3c0ef626 | 827 | } |
3c0ef626 | 828 | /* |
829 | * If not in strict mode, add the key automatically to the | |
830 | * local known_hosts file. | |
831 | */ | |
996d5e62 | 832 | if (options.check_host_ip && ip_status == HOST_NEW) { |
833 | snprintf(hostline, sizeof(hostline), "%s,%s", | |
834 | host, ip); | |
835 | hostp = hostline; | |
836 | if (options.hash_known_hosts) { | |
837 | /* Add hash of host and IP separately */ | |
838 | r = add_host_to_hostfile(user_hostfile, host, | |
839 | host_key, options.hash_known_hosts) && | |
840 | add_host_to_hostfile(user_hostfile, ip, | |
841 | host_key, options.hash_known_hosts); | |
842 | } else { | |
843 | /* Add unhashed "host,ip" */ | |
844 | r = add_host_to_hostfile(user_hostfile, | |
845 | hostline, host_key, | |
846 | options.hash_known_hosts); | |
847 | } | |
848 | } else { | |
849 | r = add_host_to_hostfile(user_hostfile, host, host_key, | |
850 | options.hash_known_hosts); | |
851 | hostp = host; | |
852 | } | |
853 | ||
854 | if (!r) | |
0fff78ff | 855 | logit("Failed to add the host to the list of known " |
3c0ef626 | 856 | "hosts (%.500s).", user_hostfile); |
857 | else | |
0fff78ff | 858 | logit("Warning: Permanently added '%.200s' (%s) to the " |
3c0ef626 | 859 | "list of known hosts.", hostp, type); |
860 | break; | |
861 | case HOST_CHANGED: | |
9108f8d9 | 862 | if (readonly == ROQUIET) |
863 | goto fail; | |
3c0ef626 | 864 | if (options.check_host_ip && host_ip_differ) { |
c9f39d2c | 865 | char *key_msg; |
3c0ef626 | 866 | if (ip_status == HOST_NEW) |
c9f39d2c | 867 | key_msg = "is unknown"; |
3c0ef626 | 868 | else if (ip_status == HOST_OK) |
c9f39d2c | 869 | key_msg = "is unchanged"; |
3c0ef626 | 870 | else |
c9f39d2c | 871 | key_msg = "has a different value"; |
3c0ef626 | 872 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
873 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
874 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
875 | error("The %s host key for %s has changed,", type, host); | |
22616013 | 876 | error("and the key for the corresponding IP address %s", ip); |
c9f39d2c | 877 | error("%s. This could either mean that", key_msg); |
3c0ef626 | 878 | error("DNS SPOOFING is happening or the IP address for the host"); |
879 | error("and its host key have changed at the same time."); | |
880 | if (ip_status != HOST_NEW) | |
881 | error("Offending key for IP in %s:%d", ip_file, ip_line); | |
882 | } | |
883 | /* The host key has changed. */ | |
cdd66111 | 884 | warn_changed_key(host_key); |
3c0ef626 | 885 | error("Add correct host key in %.100s to get rid of this message.", |
886 | user_hostfile); | |
887 | error("Offending key in %s:%d", host_file, host_line); | |
3c0ef626 | 888 | |
889 | /* | |
890 | * If strict host key checking is in use, the user will have | |
891 | * to edit the key manually and we can only abort. | |
892 | */ | |
893 | if (options.strict_host_key_checking) { | |
894 | error("%s host key for %.200s has changed and you have " | |
895 | "requested strict checking.", type, host); | |
896 | goto fail; | |
897 | } | |
898 | ||
899 | /* | |
900 | * If strict host key checking has not been requested, allow | |
0fff78ff | 901 | * the connection but without MITM-able authentication or |
9108f8d9 | 902 | * forwarding. |
3c0ef626 | 903 | */ |
904 | if (options.password_authentication) { | |
905 | error("Password authentication is disabled to avoid " | |
906 | "man-in-the-middle attacks."); | |
907 | options.password_authentication = 0; | |
22616013 | 908 | cancelled_forwarding = 1; |
3c0ef626 | 909 | } |
0fff78ff | 910 | if (options.kbd_interactive_authentication) { |
911 | error("Keyboard-interactive authentication is disabled" | |
912 | " to avoid man-in-the-middle attacks."); | |
913 | options.kbd_interactive_authentication = 0; | |
914 | options.challenge_response_authentication = 0; | |
22616013 | 915 | cancelled_forwarding = 1; |
0fff78ff | 916 | } |
917 | if (options.challenge_response_authentication) { | |
918 | error("Challenge/response authentication is disabled" | |
919 | " to avoid man-in-the-middle attacks."); | |
920 | options.challenge_response_authentication = 0; | |
22616013 | 921 | cancelled_forwarding = 1; |
0fff78ff | 922 | } |
3c0ef626 | 923 | if (options.forward_agent) { |
924 | error("Agent forwarding is disabled to avoid " | |
925 | "man-in-the-middle attacks."); | |
926 | options.forward_agent = 0; | |
22616013 | 927 | cancelled_forwarding = 1; |
3c0ef626 | 928 | } |
929 | if (options.forward_x11) { | |
930 | error("X11 forwarding is disabled to avoid " | |
931 | "man-in-the-middle attacks."); | |
932 | options.forward_x11 = 0; | |
22616013 | 933 | cancelled_forwarding = 1; |
3c0ef626 | 934 | } |
935 | if (options.num_local_forwards > 0 || | |
936 | options.num_remote_forwards > 0) { | |
937 | error("Port forwarding is disabled to avoid " | |
938 | "man-in-the-middle attacks."); | |
939 | options.num_local_forwards = | |
e9a17296 | 940 | options.num_remote_forwards = 0; |
22616013 | 941 | cancelled_forwarding = 1; |
3c0ef626 | 942 | } |
9108f8d9 | 943 | if (options.tun_open != SSH_TUNMODE_NO) { |
944 | error("Tunnel forwarding is disabled to avoid " | |
945 | "man-in-the-middle attacks."); | |
946 | options.tun_open = SSH_TUNMODE_NO; | |
22616013 | 947 | cancelled_forwarding = 1; |
9108f8d9 | 948 | } |
22616013 | 949 | if (options.exit_on_forward_failure && cancelled_forwarding) |
950 | fatal("Error: forwarding disabled due to host key " | |
951 | "check failure"); | |
952 | ||
3c0ef626 | 953 | /* |
954 | * XXX Should permit the user to change to use the new id. | |
955 | * This could be done by converting the host key to an | |
956 | * identifying sentence, tell that the host identifies itself | |
957 | * by that sentence, and ask the user if he/she whishes to | |
958 | * accept the authentication. | |
959 | */ | |
960 | break; | |
41b2f314 | 961 | case HOST_FOUND: |
962 | fatal("internal error"); | |
963 | break; | |
3c0ef626 | 964 | } |
965 | ||
966 | if (options.check_host_ip && host_status != HOST_CHANGED && | |
967 | ip_status == HOST_CHANGED) { | |
e9a17296 | 968 | snprintf(msg, sizeof(msg), |
969 | "Warning: the %s host key for '%.200s' " | |
970 | "differs from the key for the IP address '%.128s'" | |
971 | "\nOffending key for IP in %s:%d", | |
972 | type, host, ip, ip_file, ip_line); | |
973 | if (host_status == HOST_OK) { | |
974 | len = strlen(msg); | |
975 | snprintf(msg + len, sizeof(msg) - len, | |
976 | "\nMatching host key in %s:%d", | |
f5799ae1 | 977 | host_file, host_line); |
e9a17296 | 978 | } |
3c0ef626 | 979 | if (options.strict_host_key_checking == 1) { |
0fff78ff | 980 | logit("%s", msg); |
3c0ef626 | 981 | error("Exiting, you have requested strict checking."); |
982 | goto fail; | |
983 | } else if (options.strict_host_key_checking == 2) { | |
e9a17296 | 984 | strlcat(msg, "\nAre you sure you want " |
985 | "to continue connecting (yes/no)? ", sizeof(msg)); | |
986 | if (!confirm(msg)) | |
3c0ef626 | 987 | goto fail; |
e9a17296 | 988 | } else { |
0fff78ff | 989 | logit("%s", msg); |
3c0ef626 | 990 | } |
991 | } | |
992 | ||
993 | xfree(ip); | |
9108f8d9 | 994 | xfree(host); |
3c0ef626 | 995 | return 0; |
996 | ||
997 | fail: | |
998 | xfree(ip); | |
9108f8d9 | 999 | xfree(host); |
3c0ef626 | 1000 | return -1; |
1001 | } | |
1002 | ||
0fff78ff | 1003 | /* returns 0 if key verifies or -1 if key does NOT verify */ |
3c0ef626 | 1004 | int |
1005 | verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) | |
1006 | { | |
1007 | struct stat st; | |
cdd66111 | 1008 | int flags = 0; |
12408a1b | 1009 | |
cdd66111 | 1010 | if (options.verify_host_key_dns && |
1011 | verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) { | |
1012 | ||
1013 | if (flags & DNS_VERIFY_FOUND) { | |
1014 | ||
1015 | if (options.verify_host_key_dns == 1 && | |
1016 | flags & DNS_VERIFY_MATCH && | |
1017 | flags & DNS_VERIFY_SECURE) | |
1018 | return 0; | |
1019 | ||
1020 | if (flags & DNS_VERIFY_MATCH) { | |
1021 | matching_host_key_dns = 1; | |
1022 | } else { | |
1023 | warn_changed_key(host_key); | |
1024 | error("Update the SSHFP RR in DNS with the new " | |
1025 | "host key to get rid of this message."); | |
1026 | } | |
0fff78ff | 1027 | } |
1028 | } | |
0fff78ff | 1029 | |
3c0ef626 | 1030 | /* return ok if the key can be found in an old keyfile */ |
1031 | if (stat(options.system_hostfile2, &st) == 0 || | |
1032 | stat(options.user_hostfile2, &st) == 0) { | |
9108f8d9 | 1033 | if (check_host_key(host, hostaddr, options.port, host_key, |
1034 | RDONLY, options.user_hostfile2, | |
1035 | options.system_hostfile2) == 0) | |
3c0ef626 | 1036 | return 0; |
1037 | } | |
9108f8d9 | 1038 | return check_host_key(host, hostaddr, options.port, host_key, |
1039 | RDRW, options.user_hostfile, options.system_hostfile); | |
3c0ef626 | 1040 | } |
1041 | ||
1042 | /* | |
1043 | * Starts a dialog with the server, and authenticates the current user on the | |
1044 | * server. This does not need any extra privileges. The basic connection | |
1045 | * to the server must already have been established before this is called. | |
1046 | * If login fails, this function prints an error and never returns. | |
1047 | * This function does not require super-user privileges. | |
1048 | */ | |
1049 | void | |
f5799ae1 | 1050 | ssh_login(Sensitive *sensitive, const char *orighost, |
47686178 | 1051 | struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms) |
3c0ef626 | 1052 | { |
1053 | char *host, *cp; | |
1054 | char *server_user, *local_user; | |
1055 | ||
1056 | local_user = xstrdup(pw->pw_name); | |
1057 | server_user = options.user ? options.user : local_user; | |
1058 | ||
1059 | /* Convert the user-supplied hostname into all lowercase. */ | |
1060 | host = xstrdup(orighost); | |
1061 | for (cp = host; *cp; cp++) | |
1062 | if (isupper(*cp)) | |
9108f8d9 | 1063 | *cp = (char)tolower(*cp); |
3c0ef626 | 1064 | |
1065 | /* Exchange protocol version identification strings with the server. */ | |
47686178 | 1066 | ssh_exchange_identification(timeout_ms); |
3c0ef626 | 1067 | |
1068 | /* Put the connection into non-blocking mode. */ | |
1069 | packet_set_nonblocking(); | |
1070 | ||
1071 | /* key exchange */ | |
1072 | /* authenticate user */ | |
1073 | if (compat20) { | |
1074 | ssh_kex2(host, hostaddr); | |
f5799ae1 | 1075 | ssh_userauth2(local_user, server_user, host, sensitive); |
3c0ef626 | 1076 | } else { |
1077 | ssh_kex(host, hostaddr); | |
f5799ae1 | 1078 | ssh_userauth1(local_user, server_user, host, sensitive); |
3c0ef626 | 1079 | } |
9108f8d9 | 1080 | xfree(local_user); |
3c0ef626 | 1081 | } |
1082 | ||
1083 | void | |
1084 | ssh_put_password(char *password) | |
1085 | { | |
1086 | int size; | |
1087 | char *padded; | |
1088 | ||
1089 | if (datafellows & SSH_BUG_PASSWORDPAD) { | |
1090 | packet_put_cstring(password); | |
1091 | return; | |
1092 | } | |
1093 | size = roundup(strlen(password) + 1, 32); | |
9108f8d9 | 1094 | padded = xcalloc(1, size); |
3c0ef626 | 1095 | strlcpy(padded, password, size); |
1096 | packet_put_string(padded, size); | |
1097 | memset(padded, 0, size); | |
1098 | xfree(padded); | |
1099 | } | |
41b2f314 | 1100 | |
1101 | static int | |
1102 | show_key_from_file(const char *file, const char *host, int keytype) | |
1103 | { | |
1104 | Key *found; | |
22616013 | 1105 | char *fp, *ra; |
41b2f314 | 1106 | int line, ret; |
1107 | ||
1108 | found = key_new(keytype); | |
1109 | if ((ret = lookup_key_in_hostfile_by_type(file, host, | |
1110 | keytype, found, &line))) { | |
1111 | fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX); | |
22616013 | 1112 | ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART); |
0fff78ff | 1113 | logit("WARNING: %s key found for host %s\n" |
41b2f314 | 1114 | "in %s:%d\n" |
22616013 | 1115 | "%s key fingerprint %s.\n%s\n", |
41b2f314 | 1116 | key_type(found), host, file, line, |
22616013 | 1117 | key_type(found), fp, ra); |
1118 | xfree(ra); | |
41b2f314 | 1119 | xfree(fp); |
1120 | } | |
1121 | key_free(found); | |
1122 | return (ret); | |
1123 | } | |
1124 | ||
1125 | /* print all known host keys for a given host, but skip keys of given type */ | |
1126 | static int | |
1127 | show_other_keys(const char *host, Key *key) | |
1128 | { | |
1129 | int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1}; | |
1130 | int i, found = 0; | |
1131 | ||
1132 | for (i = 0; type[i] != -1; i++) { | |
1133 | if (type[i] == key->type) | |
1134 | continue; | |
1135 | if (type[i] != KEY_RSA1 && | |
1136 | show_key_from_file(options.user_hostfile2, host, type[i])) { | |
1137 | found = 1; | |
1138 | continue; | |
1139 | } | |
1140 | if (type[i] != KEY_RSA1 && | |
1141 | show_key_from_file(options.system_hostfile2, host, type[i])) { | |
1142 | found = 1; | |
1143 | continue; | |
1144 | } | |
1145 | if (show_key_from_file(options.user_hostfile, host, type[i])) { | |
1146 | found = 1; | |
1147 | continue; | |
1148 | } | |
1149 | if (show_key_from_file(options.system_hostfile, host, type[i])) { | |
1150 | found = 1; | |
1151 | continue; | |
1152 | } | |
1153 | debug2("no key of type %d for host %s", type[i], host); | |
1154 | } | |
1155 | return (found); | |
1156 | } | |
cdd66111 | 1157 | |
1158 | static void | |
1159 | warn_changed_key(Key *host_key) | |
1160 | { | |
1161 | char *fp; | |
1162 | const char *type = key_type(host_key); | |
1163 | ||
1164 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); | |
1165 | ||
1166 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1167 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); | |
1168 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1169 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1170 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1171 | error("It is also possible that the %s host key has just been changed.", type); | |
1172 | error("The fingerprint for the %s key sent by the remote host is\n%s.", | |
1173 | type, fp); | |
1174 | error("Please contact your system administrator."); | |
1175 | ||
1176 | xfree(fp); | |
1177 | } | |
2c06c99b | 1178 | |
1179 | /* | |
1180 | * Execute a local command | |
1181 | */ | |
1182 | int | |
1183 | ssh_local_cmd(const char *args) | |
1184 | { | |
1185 | char *shell; | |
1186 | pid_t pid; | |
1187 | int status; | |
1188 | ||
1189 | if (!options.permit_local_command || | |
1190 | args == NULL || !*args) | |
1191 | return (1); | |
1192 | ||
1193 | if ((shell = getenv("SHELL")) == NULL) | |
1194 | shell = _PATH_BSHELL; | |
1195 | ||
1196 | pid = fork(); | |
1197 | if (pid == 0) { | |
1198 | debug3("Executing %s -c \"%s\"", shell, args); | |
1199 | execl(shell, shell, "-c", args, (char *)NULL); | |
1200 | error("Couldn't execute %s -c \"%s\": %s", | |
1201 | shell, args, strerror(errno)); | |
1202 | _exit(1); | |
1203 | } else if (pid == -1) | |
1204 | fatal("fork failed: %.100s", strerror(errno)); | |
1205 | while (waitpid(pid, &status, 0) == -1) | |
1206 | if (errno != EINTR) | |
1207 | fatal("Couldn't wait for child: %s", strerror(errno)); | |
1208 | ||
1209 | if (!WIFEXITED(status)) | |
1210 | return (1); | |
1211 | ||
1212 | return (WEXITSTATUS(status)); | |
1213 | } |