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5156b1a1 | 1 | /* $OpenBSD: sshconnect.c,v 1.211 2008/07/01 07:24:22 dtucker 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 | |
30460aeb | 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" |
30460aeb | 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" | |
473db5ab | 58 | #include "dns.h" |
30460aeb | 59 | #include "version.h" |
473db5ab | 60 | |
3c0ef626 | 61 | char *client_version_string = NULL; |
62 | char *server_version_string = NULL; | |
63 | ||
08822d99 | 64 | static int matching_host_key_dns = 0; |
473db5ab | 65 | |
66 | /* import */ | |
3c0ef626 | 67 | extern Options options; |
68 | extern char *__progname; | |
473db5ab | 69 | extern uid_t original_real_uid; |
70 | extern uid_t original_effective_uid; | |
71 | extern pid_t proxy_command_pid; | |
3c0ef626 | 72 | |
73 | #ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */ | |
74 | #define INET6_ADDRSTRLEN 46 | |
75 | #endif | |
76 | ||
473db5ab | 77 | static int show_other_keys(const char *, Key *); |
78 | static void warn_changed_key(Key *); | |
3c0ef626 | 79 | |
80 | /* | |
81 | * Connect to the given ssh server using a proxy command. | |
82 | */ | |
83 | static int | |
473db5ab | 84 | ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) |
3c0ef626 | 85 | { |
473db5ab | 86 | char *command_string, *tmp; |
3c0ef626 | 87 | int pin[2], pout[2]; |
88 | pid_t pid; | |
e74dc197 | 89 | char *shell, strport[NI_MAXSERV]; |
90 | ||
91 | if ((shell = getenv("SHELL")) == NULL) | |
92 | shell = _PATH_BSHELL; | |
3c0ef626 | 93 | |
94 | /* Convert the port number into a string. */ | |
95 | snprintf(strport, sizeof strport, "%hu", port); | |
96 | ||
473db5ab | 97 | /* |
98 | * Build the final command string in the buffer by making the | |
99 | * appropriate substitutions to the given proxy command. | |
100 | * | |
101 | * Use "exec" to avoid "sh -c" processes on some platforms | |
102 | * (e.g. Solaris) | |
103 | */ | |
30460aeb | 104 | xasprintf(&tmp, "exec %s", proxy_command); |
473db5ab | 105 | command_string = percent_expand(tmp, "h", host, |
106 | "p", strport, (char *)NULL); | |
107 | xfree(tmp); | |
3c0ef626 | 108 | |
109 | /* Create pipes for communicating with the proxy. */ | |
110 | if (pipe(pin) < 0 || pipe(pout) < 0) | |
111 | fatal("Could not create pipes to communicate with the proxy: %.100s", | |
473db5ab | 112 | strerror(errno)); |
3c0ef626 | 113 | |
114 | debug("Executing proxy command: %.500s", command_string); | |
115 | ||
116 | /* Fork and execute the proxy command. */ | |
117 | if ((pid = fork()) == 0) { | |
118 | char *argv[10]; | |
119 | ||
120 | /* Child. Permanently give up superuser privileges. */ | |
30460aeb | 121 | permanently_drop_suid(original_real_uid); |
3c0ef626 | 122 | |
123 | /* Redirect stdin and stdout. */ | |
124 | close(pin[1]); | |
125 | if (pin[0] != 0) { | |
126 | if (dup2(pin[0], 0) < 0) | |
127 | perror("dup2 stdin"); | |
128 | close(pin[0]); | |
129 | } | |
130 | close(pout[0]); | |
131 | if (dup2(pout[1], 1) < 0) | |
132 | perror("dup2 stdout"); | |
133 | /* Cannot be 1 because pin allocated two descriptors. */ | |
134 | close(pout[1]); | |
135 | ||
136 | /* Stderr is left as it is so that error messages get | |
137 | printed on the user's terminal. */ | |
e74dc197 | 138 | argv[0] = shell; |
3c0ef626 | 139 | argv[1] = "-c"; |
140 | argv[2] = command_string; | |
141 | argv[3] = NULL; | |
142 | ||
143 | /* Execute the proxy command. Note that we gave up any | |
144 | extra privileges above. */ | |
145 | execv(argv[0], argv); | |
146 | perror(argv[0]); | |
147 | exit(1); | |
148 | } | |
149 | /* Parent. */ | |
150 | if (pid < 0) | |
151 | fatal("fork failed: %.100s", strerror(errno)); | |
473db5ab | 152 | else |
153 | proxy_command_pid = pid; /* save pid to clean up later */ | |
3c0ef626 | 154 | |
155 | /* Close child side of the descriptors. */ | |
156 | close(pin[0]); | |
157 | close(pout[1]); | |
158 | ||
159 | /* Free the command name. */ | |
473db5ab | 160 | xfree(command_string); |
3c0ef626 | 161 | |
162 | /* Set the connection file descriptors. */ | |
163 | packet_set_connection(pout[0], pin[1]); | |
5156b1a1 | 164 | packet_set_timeout(options.server_alive_interval, |
165 | options.server_alive_count_max); | |
3c0ef626 | 166 | |
167 | /* Indicate OK return */ | |
168 | return 0; | |
169 | } | |
170 | ||
a7213e65 | 171 | /* |
172 | * Set TCP receive buffer if requested. | |
173 | * Note: tuning needs to happen after the socket is | |
174 | * created but before the connection happens | |
175 | * so winscale is negotiated properly -cjr | |
176 | */ | |
177 | static void | |
178 | ssh_set_socket_recvbuf(int sock) | |
179 | { | |
180 | void *buf = (void *)&options.tcp_rcv_buf; | |
181 | int sz = sizeof(options.tcp_rcv_buf); | |
182 | int socksize; | |
183 | int socksizelen = sizeof(int); | |
184 | ||
185 | debug("setsockopt Attempting to set SO_RCVBUF to %d", options.tcp_rcv_buf); | |
186 | if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF, buf, sz) >= 0) { | |
187 | getsockopt(sock, SOL_SOCKET, SO_RCVBUF, &socksize, &socksizelen); | |
188 | debug("setsockopt SO_RCVBUF: %.100s %d", strerror(errno), socksize); | |
189 | } | |
190 | else | |
191 | error("Couldn't set socket receive buffer to %d: %.100s", | |
192 | options.tcp_rcv_buf, strerror(errno)); | |
193 | } | |
194 | ||
195 | ||
3c0ef626 | 196 | /* |
197 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
198 | */ | |
199 | static int | |
473db5ab | 200 | ssh_create_socket(int privileged, struct addrinfo *ai) |
3c0ef626 | 201 | { |
202 | int sock, gaierr; | |
203 | struct addrinfo hints, *res; | |
204 | ||
205 | /* | |
206 | * If we are running as root and want to connect to a privileged | |
207 | * port, bind our own socket to a privileged port. | |
208 | */ | |
209 | if (privileged) { | |
210 | int p = IPPORT_RESERVED - 1; | |
473db5ab | 211 | PRIV_START; |
212 | sock = rresvport_af(&p, ai->ai_family); | |
213 | PRIV_END; | |
3c0ef626 | 214 | if (sock < 0) |
473db5ab | 215 | error("rresvport: af=%d %.100s", ai->ai_family, |
216 | strerror(errno)); | |
3c0ef626 | 217 | else |
218 | debug("Allocated local port %d.", p); | |
473db5ab | 219 | |
a7213e65 | 220 | if (options.tcp_rcv_buf > 0) |
221 | ssh_set_socket_recvbuf(sock); | |
3c0ef626 | 222 | return sock; |
223 | } | |
473db5ab | 224 | sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); |
3c0ef626 | 225 | if (sock < 0) |
226 | error("socket: %.100s", strerror(errno)); | |
473db5ab | 227 | |
6df46d40 | 228 | |
229 | if (options.tcp_rcv_buf > 0) | |
230 | ssh_set_socket_recvbuf(sock); | |
4834571d | 231 | |
d3057ca4 | 232 | if (options.tcp_rcv_buf > 0) |
233 | ssh_set_socket_recvbuf(sock); | |
234 | ||
4834571d | 235 | /* Bind the socket to an alternative local IP address */ |
3c0ef626 | 236 | if (options.bind_address == NULL) |
237 | return sock; | |
238 | ||
239 | memset(&hints, 0, sizeof(hints)); | |
473db5ab | 240 | hints.ai_family = ai->ai_family; |
241 | hints.ai_socktype = ai->ai_socktype; | |
242 | hints.ai_protocol = ai->ai_protocol; | |
3c0ef626 | 243 | hints.ai_flags = AI_PASSIVE; |
5156b1a1 | 244 | gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res); |
3c0ef626 | 245 | if (gaierr) { |
246 | error("getaddrinfo: %s: %s", options.bind_address, | |
e74dc197 | 247 | ssh_gai_strerror(gaierr)); |
3c0ef626 | 248 | close(sock); |
249 | return -1; | |
250 | } | |
251 | if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { | |
252 | error("bind: %s: %s", options.bind_address, strerror(errno)); | |
253 | close(sock); | |
254 | freeaddrinfo(res); | |
255 | return -1; | |
256 | } | |
257 | freeaddrinfo(res); | |
258 | return sock; | |
259 | } | |
260 | ||
473db5ab | 261 | static int |
262 | timeout_connect(int sockfd, const struct sockaddr *serv_addr, | |
e74dc197 | 263 | socklen_t addrlen, int *timeoutp) |
473db5ab | 264 | { |
265 | fd_set *fdset; | |
e74dc197 | 266 | struct timeval tv, t_start; |
473db5ab | 267 | socklen_t optlen; |
30460aeb | 268 | int optval, rc, result = -1; |
473db5ab | 269 | |
e74dc197 | 270 | gettimeofday(&t_start, NULL); |
271 | ||
272 | if (*timeoutp <= 0) { | |
273 | result = connect(sockfd, serv_addr, addrlen); | |
274 | goto done; | |
275 | } | |
473db5ab | 276 | |
277 | set_nonblock(sockfd); | |
278 | rc = connect(sockfd, serv_addr, addrlen); | |
279 | if (rc == 0) { | |
280 | unset_nonblock(sockfd); | |
e74dc197 | 281 | result = 0; |
282 | goto done; | |
283 | } | |
284 | if (errno != EINPROGRESS) { | |
285 | result = -1; | |
286 | goto done; | |
473db5ab | 287 | } |
473db5ab | 288 | |
30460aeb | 289 | fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS), |
290 | sizeof(fd_mask)); | |
473db5ab | 291 | FD_SET(sockfd, fdset); |
e74dc197 | 292 | ms_to_timeval(&tv, *timeoutp); |
473db5ab | 293 | |
294 | for (;;) { | |
295 | rc = select(sockfd + 1, NULL, fdset, NULL, &tv); | |
296 | if (rc != -1 || errno != EINTR) | |
297 | break; | |
298 | } | |
299 | ||
300 | switch (rc) { | |
301 | case 0: | |
302 | /* Timed out */ | |
303 | errno = ETIMEDOUT; | |
304 | break; | |
305 | case -1: | |
306 | /* Select error */ | |
307 | debug("select: %s", strerror(errno)); | |
308 | break; | |
309 | case 1: | |
310 | /* Completed or failed */ | |
311 | optval = 0; | |
312 | optlen = sizeof(optval); | |
313 | if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, | |
314 | &optlen) == -1) { | |
315 | debug("getsockopt: %s", strerror(errno)); | |
316 | break; | |
317 | } | |
318 | if (optval != 0) { | |
319 | errno = optval; | |
320 | break; | |
321 | } | |
322 | result = 0; | |
323 | unset_nonblock(sockfd); | |
324 | break; | |
325 | default: | |
326 | /* Should not occur */ | |
327 | fatal("Bogus return (%d) from select()", rc); | |
328 | } | |
329 | ||
330 | xfree(fdset); | |
e74dc197 | 331 | |
332 | done: | |
333 | if (result == 0 && *timeoutp > 0) { | |
334 | ms_subtract_diff(&t_start, timeoutp); | |
335 | if (*timeoutp <= 0) { | |
336 | errno = ETIMEDOUT; | |
337 | result = -1; | |
338 | } | |
339 | } | |
340 | ||
473db5ab | 341 | return (result); |
342 | } | |
343 | ||
3c0ef626 | 344 | /* |
345 | * Opens a TCP/IP connection to the remote server on the given host. | |
346 | * The address of the remote host will be returned in hostaddr. | |
473db5ab | 347 | * If port is 0, the default port will be used. If needpriv is true, |
3c0ef626 | 348 | * a privileged port will be allocated to make the connection. |
473db5ab | 349 | * This requires super-user privileges if needpriv is true. |
3c0ef626 | 350 | * Connection_attempts specifies the maximum number of tries (one per |
351 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
352 | * and %p substituted for host and port, respectively) to use to contact | |
353 | * the daemon. | |
3c0ef626 | 354 | */ |
355 | int | |
356 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, | |
e74dc197 | 357 | u_short port, int family, int connection_attempts, int *timeout_ms, |
358 | int want_keepalive, int needpriv, const char *proxy_command) | |
3c0ef626 | 359 | { |
360 | int gaierr; | |
361 | int on = 1; | |
362 | int sock = -1, attempt; | |
363 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
364 | struct addrinfo hints, *ai, *aitop; | |
3c0ef626 | 365 | |
473db5ab | 366 | debug2("ssh_connect: needpriv %d", needpriv); |
3c0ef626 | 367 | |
3c0ef626 | 368 | /* If a proxy command is given, connect using it. */ |
369 | if (proxy_command != NULL) | |
473db5ab | 370 | return ssh_proxy_connect(host, port, proxy_command); |
3c0ef626 | 371 | |
372 | /* No proxy command. */ | |
373 | ||
374 | memset(&hints, 0, sizeof(hints)); | |
375 | hints.ai_family = family; | |
376 | hints.ai_socktype = SOCK_STREAM; | |
473db5ab | 377 | snprintf(strport, sizeof strport, "%u", port); |
3c0ef626 | 378 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) |
e74dc197 | 379 | fatal("%s: Could not resolve hostname %.100s: %s", __progname, |
380 | host, ssh_gai_strerror(gaierr)); | |
3c0ef626 | 381 | |
30460aeb | 382 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
240debe0 | 383 | if (attempt > 0) { |
384 | /* Sleep a moment before retrying. */ | |
385 | sleep(1); | |
3c0ef626 | 386 | debug("Trying again..."); |
240debe0 | 387 | } |
30460aeb | 388 | /* |
389 | * Loop through addresses for this host, and try each one in | |
390 | * sequence until the connection succeeds. | |
391 | */ | |
3c0ef626 | 392 | for (ai = aitop; ai; ai = ai->ai_next) { |
393 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
394 | continue; | |
395 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
396 | ntop, sizeof(ntop), strport, sizeof(strport), | |
397 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
398 | error("ssh_connect: getnameinfo failed"); | |
399 | continue; | |
400 | } | |
401 | debug("Connecting to %.200s [%.100s] port %s.", | |
402 | host, ntop, strport); | |
403 | ||
404 | /* Create a socket for connecting. */ | |
473db5ab | 405 | sock = ssh_create_socket(needpriv, ai); |
3c0ef626 | 406 | if (sock < 0) |
407 | /* Any error is already output */ | |
408 | continue; | |
409 | ||
473db5ab | 410 | if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, |
e74dc197 | 411 | timeout_ms) >= 0) { |
3c0ef626 | 412 | /* Successful connection. */ |
413 | memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); | |
3c0ef626 | 414 | break; |
415 | } else { | |
473db5ab | 416 | debug("connect to address %s port %s: %s", |
417 | ntop, strport, strerror(errno)); | |
3c0ef626 | 418 | close(sock); |
30460aeb | 419 | sock = -1; |
3c0ef626 | 420 | } |
421 | } | |
30460aeb | 422 | if (sock != -1) |
3c0ef626 | 423 | break; /* Successful connection. */ |
3c0ef626 | 424 | } |
425 | ||
426 | freeaddrinfo(aitop); | |
427 | ||
428 | /* Return failure if we didn't get a successful connection. */ | |
30460aeb | 429 | if (sock == -1) { |
473db5ab | 430 | error("ssh: connect to host %s port %s: %s", |
431 | host, strport, strerror(errno)); | |
432 | return (-1); | |
433 | } | |
3c0ef626 | 434 | |
435 | debug("Connection established."); | |
436 | ||
473db5ab | 437 | /* Set SO_KEEPALIVE if requested. */ |
e74dc197 | 438 | if (want_keepalive && |
3c0ef626 | 439 | setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, |
440 | sizeof(on)) < 0) | |
441 | error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); | |
442 | ||
443 | /* Set the connection. */ | |
444 | packet_set_connection(sock, sock); | |
5156b1a1 | 445 | packet_set_timeout(options.server_alive_interval, |
446 | options.server_alive_count_max); | |
3c0ef626 | 447 | |
448 | return 0; | |
449 | } | |
450 | ||
451 | /* | |
452 | * Waits for the server identification string, and sends our own | |
453 | * identification string. | |
454 | */ | |
455 | static void | |
e74dc197 | 456 | ssh_exchange_identification(int timeout_ms) |
3c0ef626 | 457 | { |
458 | char buf[256], remote_version[256]; /* must be same size! */ | |
473db5ab | 459 | int remote_major, remote_minor, mismatch; |
3c0ef626 | 460 | int connection_in = packet_get_connection_in(); |
461 | int connection_out = packet_get_connection_out(); | |
462 | int minor1 = PROTOCOL_MINOR_1; | |
30460aeb | 463 | u_int i, n; |
e74dc197 | 464 | size_t len; |
465 | int fdsetsz, remaining, rc; | |
466 | struct timeval t_start, t_remaining; | |
467 | fd_set *fdset; | |
468 | ||
469 | fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask); | |
470 | fdset = xcalloc(1, fdsetsz); | |
3c0ef626 | 471 | |
473db5ab | 472 | /* Read other side's version identification. */ |
e74dc197 | 473 | remaining = timeout_ms; |
30460aeb | 474 | for (n = 0;;) { |
3c0ef626 | 475 | for (i = 0; i < sizeof(buf) - 1; i++) { |
e74dc197 | 476 | if (timeout_ms > 0) { |
477 | gettimeofday(&t_start, NULL); | |
478 | ms_to_timeval(&t_remaining, remaining); | |
479 | FD_SET(connection_in, fdset); | |
480 | rc = select(connection_in + 1, fdset, NULL, | |
481 | fdset, &t_remaining); | |
482 | ms_subtract_diff(&t_start, &remaining); | |
483 | if (rc == 0 || remaining <= 0) | |
484 | fatal("Connection timed out during " | |
485 | "banner exchange"); | |
486 | if (rc == -1) { | |
487 | if (errno == EINTR) | |
488 | continue; | |
489 | fatal("ssh_exchange_identification: " | |
490 | "select: %s", strerror(errno)); | |
491 | } | |
492 | } | |
493 | ||
494 | len = atomicio(read, connection_in, &buf[i], 1); | |
473db5ab | 495 | |
496 | if (len != 1 && errno == EPIPE) | |
e74dc197 | 497 | fatal("ssh_exchange_identification: " |
498 | "Connection closed by remote host"); | |
473db5ab | 499 | else if (len != 1) |
e74dc197 | 500 | fatal("ssh_exchange_identification: " |
501 | "read: %.100s", strerror(errno)); | |
3c0ef626 | 502 | if (buf[i] == '\r') { |
503 | buf[i] = '\n'; | |
504 | buf[i + 1] = 0; | |
505 | continue; /**XXX wait for \n */ | |
506 | } | |
507 | if (buf[i] == '\n') { | |
508 | buf[i + 1] = 0; | |
509 | break; | |
510 | } | |
30460aeb | 511 | if (++n > 65536) |
e74dc197 | 512 | fatal("ssh_exchange_identification: " |
513 | "No banner received"); | |
3c0ef626 | 514 | } |
515 | buf[sizeof(buf) - 1] = 0; | |
516 | if (strncmp(buf, "SSH-", 4) == 0) | |
517 | break; | |
518 | debug("ssh_exchange_identification: %s", buf); | |
519 | } | |
520 | server_version_string = xstrdup(buf); | |
e74dc197 | 521 | xfree(fdset); |
3c0ef626 | 522 | |
523 | /* | |
524 | * Check that the versions match. In future this might accept | |
525 | * several versions and set appropriate flags to handle them. | |
526 | */ | |
527 | if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n", | |
528 | &remote_major, &remote_minor, remote_version) != 3) | |
529 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
530 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
473db5ab | 531 | remote_major, remote_minor, remote_version); |
3c0ef626 | 532 | |
533 | compat_datafellows(remote_version); | |
534 | mismatch = 0; | |
535 | ||
473db5ab | 536 | switch (remote_major) { |
3c0ef626 | 537 | case 1: |
538 | if (remote_minor == 99 && | |
539 | (options.protocol & SSH_PROTO_2) && | |
540 | !(options.protocol & SSH_PROTO_1_PREFERRED)) { | |
541 | enable_compat20(); | |
542 | break; | |
543 | } | |
544 | if (!(options.protocol & SSH_PROTO_1)) { | |
545 | mismatch = 1; | |
546 | break; | |
547 | } | |
548 | if (remote_minor < 3) { | |
549 | fatal("Remote machine has too old SSH software version."); | |
550 | } else if (remote_minor == 3 || remote_minor == 4) { | |
551 | /* We speak 1.3, too. */ | |
552 | enable_compat13(); | |
553 | minor1 = 3; | |
554 | if (options.forward_agent) { | |
473db5ab | 555 | logit("Agent forwarding disabled for protocol 1.3"); |
3c0ef626 | 556 | options.forward_agent = 0; |
557 | } | |
558 | } | |
559 | break; | |
560 | case 2: | |
561 | if (options.protocol & SSH_PROTO_2) { | |
562 | enable_compat20(); | |
563 | break; | |
564 | } | |
565 | /* FALLTHROUGH */ | |
566 | default: | |
567 | mismatch = 1; | |
568 | break; | |
569 | } | |
570 | if (mismatch) | |
571 | fatal("Protocol major versions differ: %d vs. %d", | |
572 | (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, | |
573 | remote_major); | |
574 | /* Send our own protocol version identification. */ | |
5156b1a1 | 575 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s%s", |
3c0ef626 | 576 | compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, |
577 | compat20 ? PROTOCOL_MINOR_2 : minor1, | |
5156b1a1 | 578 | SSH_RELEASE, compat20 ? "\r\n" : "\n"); |
473db5ab | 579 | if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf)) |
3c0ef626 | 580 | fatal("write: %.100s", strerror(errno)); |
581 | client_version_string = xstrdup(buf); | |
582 | chop(client_version_string); | |
583 | chop(server_version_string); | |
584 | debug("Local version string %.100s", client_version_string); | |
585 | } | |
586 | ||
587 | /* defaults to 'no' */ | |
588 | static int | |
589 | confirm(const char *prompt) | |
590 | { | |
473db5ab | 591 | const char *msg, *again = "Please type 'yes' or 'no': "; |
592 | char *p; | |
593 | int ret = -1; | |
3c0ef626 | 594 | |
595 | if (options.batch_mode) | |
596 | return 0; | |
473db5ab | 597 | for (msg = prompt;;msg = again) { |
598 | p = read_passphrase(msg, RP_ECHO); | |
599 | if (p == NULL || | |
600 | (p[0] == '\0') || (p[0] == '\n') || | |
601 | strncasecmp(p, "no", 2) == 0) | |
602 | ret = 0; | |
603 | if (p && strncasecmp(p, "yes", 3) == 0) | |
604 | ret = 1; | |
605 | if (p) | |
606 | xfree(p); | |
607 | if (ret != -1) | |
608 | return ret; | |
3c0ef626 | 609 | } |
610 | } | |
611 | ||
612 | /* | |
613 | * check whether the supplied host key is valid, return -1 if the key | |
614 | * is not valid. the user_hostfile will not be updated if 'readonly' is true. | |
615 | */ | |
30460aeb | 616 | #define RDRW 0 |
617 | #define RDONLY 1 | |
618 | #define ROQUIET 2 | |
3c0ef626 | 619 | static int |
30460aeb | 620 | check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, |
621 | Key *host_key, int readonly, const char *user_hostfile, | |
622 | const char *system_hostfile) | |
3c0ef626 | 623 | { |
624 | Key *file_key; | |
473db5ab | 625 | const char *type = key_type(host_key); |
30460aeb | 626 | char *ip = NULL, *host = NULL; |
5156b1a1 | 627 | char hostline[1000], *hostp, *fp, *ra; |
3c0ef626 | 628 | HostStatus host_status; |
629 | HostStatus ip_status; | |
473db5ab | 630 | int r, local = 0, host_ip_differ = 0; |
3c0ef626 | 631 | int salen; |
632 | char ntop[NI_MAXHOST]; | |
473db5ab | 633 | char msg[1024]; |
5156b1a1 | 634 | int len, host_line, ip_line, cancelled_forwarding = 0; |
3c0ef626 | 635 | const char *host_file = NULL, *ip_file = NULL; |
636 | ||
637 | /* | |
638 | * Force accepting of the host key for loopback/localhost. The | |
639 | * problem is that if the home directory is NFS-mounted to multiple | |
640 | * machines, localhost will refer to a different machine in each of | |
641 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
642 | * essentially disables host authentication for localhost; however, | |
643 | * this is probably not a real problem. | |
644 | */ | |
645 | /** hostaddr == 0! */ | |
646 | switch (hostaddr->sa_family) { | |
647 | case AF_INET: | |
648 | local = (ntohl(((struct sockaddr_in *)hostaddr)-> | |
649 | sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; | |
650 | salen = sizeof(struct sockaddr_in); | |
651 | break; | |
652 | case AF_INET6: | |
653 | local = IN6_IS_ADDR_LOOPBACK( | |
654 | &(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
655 | salen = sizeof(struct sockaddr_in6); | |
656 | break; | |
657 | default: | |
658 | local = 0; | |
659 | salen = sizeof(struct sockaddr_storage); | |
660 | break; | |
661 | } | |
662 | if (options.no_host_authentication_for_localhost == 1 && local && | |
663 | options.host_key_alias == NULL) { | |
664 | debug("Forcing accepting of host key for " | |
665 | "loopback/localhost."); | |
666 | return 0; | |
667 | } | |
668 | ||
669 | /* | |
670 | * We don't have the remote ip-address for connections | |
671 | * using a proxy command | |
672 | */ | |
673 | if (options.proxy_command == NULL) { | |
674 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), | |
675 | NULL, 0, NI_NUMERICHOST) != 0) | |
676 | fatal("check_host_key: getnameinfo failed"); | |
30460aeb | 677 | ip = put_host_port(ntop, port); |
3c0ef626 | 678 | } else { |
679 | ip = xstrdup("<no hostip for proxy command>"); | |
680 | } | |
5156b1a1 | 681 | |
3c0ef626 | 682 | /* |
683 | * Turn off check_host_ip if the connection is to localhost, via proxy | |
684 | * command or if we don't have a hostname to compare with | |
685 | */ | |
30460aeb | 686 | if (options.check_host_ip && (local || |
687 | strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) | |
3c0ef626 | 688 | options.check_host_ip = 0; |
689 | ||
690 | /* | |
30460aeb | 691 | * Allow the user to record the key under a different name or |
692 | * differentiate a non-standard port. This is useful for ssh | |
693 | * tunneling over forwarded connections or if you run multiple | |
694 | * sshd's on different ports on the same machine. | |
3c0ef626 | 695 | */ |
696 | if (options.host_key_alias != NULL) { | |
30460aeb | 697 | host = xstrdup(options.host_key_alias); |
3c0ef626 | 698 | debug("using hostkeyalias: %s", host); |
30460aeb | 699 | } else { |
700 | host = put_host_port(hostname, port); | |
3c0ef626 | 701 | } |
702 | ||
703 | /* | |
704 | * Store the host key from the known host file in here so that we can | |
705 | * compare it with the key for the IP address. | |
706 | */ | |
707 | file_key = key_new(host_key->type); | |
708 | ||
709 | /* | |
08822d99 | 710 | * Check if the host key is present in the user's list of known |
3c0ef626 | 711 | * hosts or in the systemwide list. |
712 | */ | |
713 | host_file = user_hostfile; | |
714 | host_status = check_host_in_hostfile(host_file, host, host_key, | |
473db5ab | 715 | file_key, &host_line); |
3c0ef626 | 716 | if (host_status == HOST_NEW) { |
717 | host_file = system_hostfile; | |
718 | host_status = check_host_in_hostfile(host_file, host, host_key, | |
719 | file_key, &host_line); | |
720 | } | |
721 | /* | |
722 | * Also perform check for the ip address, skip the check if we are | |
723 | * localhost or the hostname was an ip address to begin with | |
724 | */ | |
725 | if (options.check_host_ip) { | |
726 | Key *ip_key = key_new(host_key->type); | |
727 | ||
728 | ip_file = user_hostfile; | |
729 | ip_status = check_host_in_hostfile(ip_file, ip, host_key, | |
730 | ip_key, &ip_line); | |
731 | if (ip_status == HOST_NEW) { | |
732 | ip_file = system_hostfile; | |
733 | ip_status = check_host_in_hostfile(ip_file, ip, | |
734 | host_key, ip_key, &ip_line); | |
735 | } | |
736 | if (host_status == HOST_CHANGED && | |
737 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) | |
738 | host_ip_differ = 1; | |
739 | ||
740 | key_free(ip_key); | |
741 | } else | |
742 | ip_status = host_status; | |
743 | ||
744 | key_free(file_key); | |
745 | ||
746 | switch (host_status) { | |
747 | case HOST_OK: | |
748 | /* The host is known and the key matches. */ | |
749 | debug("Host '%.200s' is known and matches the %s host key.", | |
750 | host, type); | |
751 | debug("Found key in %s:%d", host_file, host_line); | |
752 | if (options.check_host_ip && ip_status == HOST_NEW) { | |
753 | if (readonly) | |
473db5ab | 754 | logit("%s host key for IP address " |
3c0ef626 | 755 | "'%.128s' not in list of known hosts.", |
756 | type, ip); | |
757 | else if (!add_host_to_hostfile(user_hostfile, ip, | |
473db5ab | 758 | host_key, options.hash_known_hosts)) |
759 | logit("Failed to add the %s host key for IP " | |
3c0ef626 | 760 | "address '%.128s' to the list of known " |
761 | "hosts (%.30s).", type, ip, user_hostfile); | |
762 | else | |
473db5ab | 763 | logit("Warning: Permanently added the %s host " |
3c0ef626 | 764 | "key for IP address '%.128s' to the list " |
765 | "of known hosts.", type, ip); | |
5156b1a1 | 766 | } else if (options.visual_host_key) { |
767 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); | |
768 | ra = key_fingerprint(host_key, SSH_FP_MD5, | |
769 | SSH_FP_RANDOMART); | |
770 | logit("Host key fingerprint is %s\n%s\n", fp, ra); | |
771 | xfree(ra); | |
772 | xfree(fp); | |
3c0ef626 | 773 | } |
774 | break; | |
775 | case HOST_NEW: | |
30460aeb | 776 | if (options.host_key_alias == NULL && port != 0 && |
777 | port != SSH_DEFAULT_PORT) { | |
778 | debug("checking without port identifier"); | |
779 | if (check_host_key(hostname, hostaddr, 0, host_key, 2, | |
780 | user_hostfile, system_hostfile) == 0) { | |
781 | debug("found matching key w/out port"); | |
782 | break; | |
783 | } | |
784 | } | |
3c0ef626 | 785 | if (readonly) |
786 | goto fail; | |
787 | /* The host is new. */ | |
788 | if (options.strict_host_key_checking == 1) { | |
789 | /* | |
790 | * User has requested strict host key checking. We | |
791 | * will not add the host key automatically. The only | |
792 | * alternative left is to abort. | |
793 | */ | |
794 | error("No %s host key is known for %.200s and you " | |
795 | "have requested strict checking.", type, host); | |
796 | goto fail; | |
797 | } else if (options.strict_host_key_checking == 2) { | |
473db5ab | 798 | char msg1[1024], msg2[1024]; |
799 | ||
800 | if (show_other_keys(host, host_key)) | |
801 | snprintf(msg1, sizeof(msg1), | |
802 | "\nbut keys of different type are already" | |
803 | " known for this host."); | |
804 | else | |
805 | snprintf(msg1, sizeof(msg1), "."); | |
3c0ef626 | 806 | /* The default */ |
3c0ef626 | 807 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); |
5156b1a1 | 808 | ra = key_fingerprint(host_key, SSH_FP_MD5, |
809 | SSH_FP_RANDOMART); | |
473db5ab | 810 | msg2[0] = '\0'; |
811 | if (options.verify_host_key_dns) { | |
812 | if (matching_host_key_dns) | |
813 | snprintf(msg2, sizeof(msg2), | |
814 | "Matching host key fingerprint" | |
815 | " found in DNS.\n"); | |
816 | else | |
817 | snprintf(msg2, sizeof(msg2), | |
818 | "No matching host key fingerprint" | |
819 | " found in DNS.\n"); | |
820 | } | |
821 | snprintf(msg, sizeof(msg), | |
3c0ef626 | 822 | "The authenticity of host '%.200s (%s)' can't be " |
473db5ab | 823 | "established%s\n" |
5156b1a1 | 824 | "%s key fingerprint is %s.%s%s\n%s" |
3c0ef626 | 825 | "Are you sure you want to continue connecting " |
473db5ab | 826 | "(yes/no)? ", |
5156b1a1 | 827 | host, ip, msg1, type, fp, |
828 | options.visual_host_key ? "\n" : "", | |
829 | options.visual_host_key ? ra : "", | |
830 | msg2); | |
831 | xfree(ra); | |
3c0ef626 | 832 | xfree(fp); |
473db5ab | 833 | if (!confirm(msg)) |
3c0ef626 | 834 | goto fail; |
3c0ef626 | 835 | } |
3c0ef626 | 836 | /* |
837 | * If not in strict mode, add the key automatically to the | |
838 | * local known_hosts file. | |
839 | */ | |
473db5ab | 840 | if (options.check_host_ip && ip_status == HOST_NEW) { |
841 | snprintf(hostline, sizeof(hostline), "%s,%s", | |
842 | host, ip); | |
843 | hostp = hostline; | |
844 | if (options.hash_known_hosts) { | |
845 | /* Add hash of host and IP separately */ | |
846 | r = add_host_to_hostfile(user_hostfile, host, | |
847 | host_key, options.hash_known_hosts) && | |
848 | add_host_to_hostfile(user_hostfile, ip, | |
849 | host_key, options.hash_known_hosts); | |
850 | } else { | |
851 | /* Add unhashed "host,ip" */ | |
852 | r = add_host_to_hostfile(user_hostfile, | |
853 | hostline, host_key, | |
854 | options.hash_known_hosts); | |
855 | } | |
856 | } else { | |
857 | r = add_host_to_hostfile(user_hostfile, host, host_key, | |
858 | options.hash_known_hosts); | |
859 | hostp = host; | |
860 | } | |
861 | ||
862 | if (!r) | |
863 | logit("Failed to add the host to the list of known " | |
3c0ef626 | 864 | "hosts (%.500s).", user_hostfile); |
865 | else | |
473db5ab | 866 | logit("Warning: Permanently added '%.200s' (%s) to the " |
3c0ef626 | 867 | "list of known hosts.", hostp, type); |
868 | break; | |
869 | case HOST_CHANGED: | |
30460aeb | 870 | if (readonly == ROQUIET) |
871 | goto fail; | |
3c0ef626 | 872 | if (options.check_host_ip && host_ip_differ) { |
473db5ab | 873 | char *key_msg; |
3c0ef626 | 874 | if (ip_status == HOST_NEW) |
473db5ab | 875 | key_msg = "is unknown"; |
3c0ef626 | 876 | else if (ip_status == HOST_OK) |
473db5ab | 877 | key_msg = "is unchanged"; |
3c0ef626 | 878 | else |
473db5ab | 879 | key_msg = "has a different value"; |
3c0ef626 | 880 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
881 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
882 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
883 | error("The %s host key for %s has changed,", type, host); | |
5156b1a1 | 884 | error("and the key for the corresponding IP address %s", ip); |
473db5ab | 885 | error("%s. This could either mean that", key_msg); |
3c0ef626 | 886 | error("DNS SPOOFING is happening or the IP address for the host"); |
887 | error("and its host key have changed at the same time."); | |
888 | if (ip_status != HOST_NEW) | |
889 | error("Offending key for IP in %s:%d", ip_file, ip_line); | |
890 | } | |
891 | /* The host key has changed. */ | |
473db5ab | 892 | warn_changed_key(host_key); |
3c0ef626 | 893 | error("Add correct host key in %.100s to get rid of this message.", |
894 | user_hostfile); | |
895 | error("Offending key in %s:%d", host_file, host_line); | |
3c0ef626 | 896 | |
897 | /* | |
898 | * If strict host key checking is in use, the user will have | |
899 | * to edit the key manually and we can only abort. | |
900 | */ | |
901 | if (options.strict_host_key_checking) { | |
902 | error("%s host key for %.200s has changed and you have " | |
903 | "requested strict checking.", type, host); | |
904 | goto fail; | |
905 | } | |
906 | ||
907 | /* | |
908 | * If strict host key checking has not been requested, allow | |
473db5ab | 909 | * the connection but without MITM-able authentication or |
30460aeb | 910 | * forwarding. |
3c0ef626 | 911 | */ |
912 | if (options.password_authentication) { | |
913 | error("Password authentication is disabled to avoid " | |
914 | "man-in-the-middle attacks."); | |
915 | options.password_authentication = 0; | |
5156b1a1 | 916 | cancelled_forwarding = 1; |
3c0ef626 | 917 | } |
473db5ab | 918 | if (options.kbd_interactive_authentication) { |
919 | error("Keyboard-interactive authentication is disabled" | |
920 | " to avoid man-in-the-middle attacks."); | |
921 | options.kbd_interactive_authentication = 0; | |
922 | options.challenge_response_authentication = 0; | |
5156b1a1 | 923 | cancelled_forwarding = 1; |
473db5ab | 924 | } |
925 | if (options.challenge_response_authentication) { | |
926 | error("Challenge/response authentication is disabled" | |
927 | " to avoid man-in-the-middle attacks."); | |
928 | options.challenge_response_authentication = 0; | |
5156b1a1 | 929 | cancelled_forwarding = 1; |
473db5ab | 930 | } |
3c0ef626 | 931 | if (options.forward_agent) { |
932 | error("Agent forwarding is disabled to avoid " | |
933 | "man-in-the-middle attacks."); | |
934 | options.forward_agent = 0; | |
5156b1a1 | 935 | cancelled_forwarding = 1; |
3c0ef626 | 936 | } |
937 | if (options.forward_x11) { | |
938 | error("X11 forwarding is disabled to avoid " | |
939 | "man-in-the-middle attacks."); | |
940 | options.forward_x11 = 0; | |
5156b1a1 | 941 | cancelled_forwarding = 1; |
3c0ef626 | 942 | } |
943 | if (options.num_local_forwards > 0 || | |
944 | options.num_remote_forwards > 0) { | |
945 | error("Port forwarding is disabled to avoid " | |
946 | "man-in-the-middle attacks."); | |
947 | options.num_local_forwards = | |
473db5ab | 948 | options.num_remote_forwards = 0; |
5156b1a1 | 949 | cancelled_forwarding = 1; |
3c0ef626 | 950 | } |
30460aeb | 951 | if (options.tun_open != SSH_TUNMODE_NO) { |
952 | error("Tunnel forwarding is disabled to avoid " | |
953 | "man-in-the-middle attacks."); | |
954 | options.tun_open = SSH_TUNMODE_NO; | |
5156b1a1 | 955 | cancelled_forwarding = 1; |
30460aeb | 956 | } |
5156b1a1 | 957 | if (options.exit_on_forward_failure && cancelled_forwarding) |
958 | fatal("Error: forwarding disabled due to host key " | |
959 | "check failure"); | |
960 | ||
3c0ef626 | 961 | /* |
962 | * XXX Should permit the user to change to use the new id. | |
963 | * This could be done by converting the host key to an | |
964 | * identifying sentence, tell that the host identifies itself | |
965 | * by that sentence, and ask the user if he/she whishes to | |
966 | * accept the authentication. | |
967 | */ | |
968 | break; | |
473db5ab | 969 | case HOST_FOUND: |
970 | fatal("internal error"); | |
971 | break; | |
3c0ef626 | 972 | } |
973 | ||
974 | if (options.check_host_ip && host_status != HOST_CHANGED && | |
975 | ip_status == HOST_CHANGED) { | |
473db5ab | 976 | snprintf(msg, sizeof(msg), |
977 | "Warning: the %s host key for '%.200s' " | |
978 | "differs from the key for the IP address '%.128s'" | |
979 | "\nOffending key for IP in %s:%d", | |
980 | type, host, ip, ip_file, ip_line); | |
981 | if (host_status == HOST_OK) { | |
982 | len = strlen(msg); | |
983 | snprintf(msg + len, sizeof(msg) - len, | |
984 | "\nMatching host key in %s:%d", | |
985 | host_file, host_line); | |
986 | } | |
3c0ef626 | 987 | if (options.strict_host_key_checking == 1) { |
473db5ab | 988 | logit("%s", msg); |
3c0ef626 | 989 | error("Exiting, you have requested strict checking."); |
990 | goto fail; | |
991 | } else if (options.strict_host_key_checking == 2) { | |
473db5ab | 992 | strlcat(msg, "\nAre you sure you want " |
993 | "to continue connecting (yes/no)? ", sizeof(msg)); | |
994 | if (!confirm(msg)) | |
3c0ef626 | 995 | goto fail; |
473db5ab | 996 | } else { |
997 | logit("%s", msg); | |
3c0ef626 | 998 | } |
999 | } | |
1000 | ||
1001 | xfree(ip); | |
30460aeb | 1002 | xfree(host); |
3c0ef626 | 1003 | return 0; |
1004 | ||
1005 | fail: | |
1006 | xfree(ip); | |
30460aeb | 1007 | xfree(host); |
3c0ef626 | 1008 | return -1; |
1009 | } | |
1010 | ||
473db5ab | 1011 | /* returns 0 if key verifies or -1 if key does NOT verify */ |
3c0ef626 | 1012 | int |
1013 | verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) | |
1014 | { | |
1015 | struct stat st; | |
473db5ab | 1016 | int flags = 0; |
1017 | ||
1018 | if (options.verify_host_key_dns && | |
1019 | verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) { | |
1020 | ||
1021 | if (flags & DNS_VERIFY_FOUND) { | |
1022 | ||
1023 | if (options.verify_host_key_dns == 1 && | |
1024 | flags & DNS_VERIFY_MATCH && | |
1025 | flags & DNS_VERIFY_SECURE) | |
1026 | return 0; | |
1027 | ||
1028 | if (flags & DNS_VERIFY_MATCH) { | |
1029 | matching_host_key_dns = 1; | |
1030 | } else { | |
1031 | warn_changed_key(host_key); | |
1032 | error("Update the SSHFP RR in DNS with the new " | |
1033 | "host key to get rid of this message."); | |
1034 | } | |
1035 | } | |
1036 | } | |
3c0ef626 | 1037 | |
1038 | /* return ok if the key can be found in an old keyfile */ | |
1039 | if (stat(options.system_hostfile2, &st) == 0 || | |
1040 | stat(options.user_hostfile2, &st) == 0) { | |
30460aeb | 1041 | if (check_host_key(host, hostaddr, options.port, host_key, |
1042 | RDONLY, options.user_hostfile2, | |
1043 | options.system_hostfile2) == 0) | |
3c0ef626 | 1044 | return 0; |
1045 | } | |
30460aeb | 1046 | return check_host_key(host, hostaddr, options.port, host_key, |
1047 | RDRW, options.user_hostfile, options.system_hostfile); | |
3c0ef626 | 1048 | } |
1049 | ||
1050 | /* | |
1051 | * Starts a dialog with the server, and authenticates the current user on the | |
1052 | * server. This does not need any extra privileges. The basic connection | |
1053 | * to the server must already have been established before this is called. | |
1054 | * If login fails, this function prints an error and never returns. | |
1055 | * This function does not require super-user privileges. | |
1056 | */ | |
1057 | void | |
473db5ab | 1058 | ssh_login(Sensitive *sensitive, const char *orighost, |
e74dc197 | 1059 | struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms) |
3c0ef626 | 1060 | { |
1061 | char *host, *cp; | |
1062 | char *server_user, *local_user; | |
1063 | ||
1064 | local_user = xstrdup(pw->pw_name); | |
1065 | server_user = options.user ? options.user : local_user; | |
1066 | ||
1067 | /* Convert the user-supplied hostname into all lowercase. */ | |
1068 | host = xstrdup(orighost); | |
1069 | for (cp = host; *cp; cp++) | |
1070 | if (isupper(*cp)) | |
30460aeb | 1071 | *cp = (char)tolower(*cp); |
3c0ef626 | 1072 | |
1073 | /* Exchange protocol version identification strings with the server. */ | |
e74dc197 | 1074 | ssh_exchange_identification(timeout_ms); |
3c0ef626 | 1075 | |
1076 | /* Put the connection into non-blocking mode. */ | |
1077 | packet_set_nonblocking(); | |
1078 | ||
1079 | /* key exchange */ | |
1080 | /* authenticate user */ | |
1081 | if (compat20) { | |
1082 | ssh_kex2(host, hostaddr); | |
473db5ab | 1083 | ssh_userauth2(local_user, server_user, host, sensitive); |
3c0ef626 | 1084 | } else { |
1085 | ssh_kex(host, hostaddr); | |
473db5ab | 1086 | ssh_userauth1(local_user, server_user, host, sensitive); |
3c0ef626 | 1087 | } |
30460aeb | 1088 | xfree(local_user); |
3c0ef626 | 1089 | } |
1090 | ||
1091 | void | |
1092 | ssh_put_password(char *password) | |
1093 | { | |
1094 | int size; | |
1095 | char *padded; | |
1096 | ||
1097 | if (datafellows & SSH_BUG_PASSWORDPAD) { | |
1098 | packet_put_cstring(password); | |
1099 | return; | |
1100 | } | |
1101 | size = roundup(strlen(password) + 1, 32); | |
30460aeb | 1102 | padded = xcalloc(1, size); |
3c0ef626 | 1103 | strlcpy(padded, password, size); |
1104 | packet_put_string(padded, size); | |
1105 | memset(padded, 0, size); | |
1106 | xfree(padded); | |
1107 | } | |
473db5ab | 1108 | |
1109 | static int | |
1110 | show_key_from_file(const char *file, const char *host, int keytype) | |
1111 | { | |
1112 | Key *found; | |
5156b1a1 | 1113 | char *fp, *ra; |
473db5ab | 1114 | int line, ret; |
1115 | ||
1116 | found = key_new(keytype); | |
1117 | if ((ret = lookup_key_in_hostfile_by_type(file, host, | |
1118 | keytype, found, &line))) { | |
1119 | fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX); | |
5156b1a1 | 1120 | ra = key_fingerprint(found, SSH_FP_MD5, SSH_FP_RANDOMART); |
473db5ab | 1121 | logit("WARNING: %s key found for host %s\n" |
1122 | "in %s:%d\n" | |
5156b1a1 | 1123 | "%s key fingerprint %s.\n%s\n", |
473db5ab | 1124 | key_type(found), host, file, line, |
5156b1a1 | 1125 | key_type(found), fp, ra); |
1126 | xfree(ra); | |
473db5ab | 1127 | xfree(fp); |
1128 | } | |
1129 | key_free(found); | |
1130 | return (ret); | |
1131 | } | |
1132 | ||
1133 | /* print all known host keys for a given host, but skip keys of given type */ | |
1134 | static int | |
1135 | show_other_keys(const char *host, Key *key) | |
1136 | { | |
1137 | int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1}; | |
1138 | int i, found = 0; | |
1139 | ||
1140 | for (i = 0; type[i] != -1; i++) { | |
1141 | if (type[i] == key->type) | |
1142 | continue; | |
1143 | if (type[i] != KEY_RSA1 && | |
1144 | show_key_from_file(options.user_hostfile2, host, type[i])) { | |
1145 | found = 1; | |
1146 | continue; | |
1147 | } | |
1148 | if (type[i] != KEY_RSA1 && | |
1149 | show_key_from_file(options.system_hostfile2, host, type[i])) { | |
1150 | found = 1; | |
1151 | continue; | |
1152 | } | |
1153 | if (show_key_from_file(options.user_hostfile, host, type[i])) { | |
1154 | found = 1; | |
1155 | continue; | |
1156 | } | |
1157 | if (show_key_from_file(options.system_hostfile, host, type[i])) { | |
1158 | found = 1; | |
1159 | continue; | |
1160 | } | |
1161 | debug2("no key of type %d for host %s", type[i], host); | |
1162 | } | |
1163 | return (found); | |
1164 | } | |
1165 | ||
1166 | static void | |
1167 | warn_changed_key(Key *host_key) | |
1168 | { | |
1169 | char *fp; | |
1170 | const char *type = key_type(host_key); | |
1171 | ||
1172 | fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); | |
1173 | ||
1174 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1175 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); | |
1176 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1177 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1178 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1179 | error("It is also possible that the %s host key has just been changed.", type); | |
1180 | error("The fingerprint for the %s key sent by the remote host is\n%s.", | |
1181 | type, fp); | |
1182 | error("Please contact your system administrator."); | |
1183 | ||
1184 | xfree(fp); | |
1185 | } | |
08822d99 | 1186 | |
1187 | /* | |
1188 | * Execute a local command | |
1189 | */ | |
1190 | int | |
1191 | ssh_local_cmd(const char *args) | |
1192 | { | |
1193 | char *shell; | |
1194 | pid_t pid; | |
1195 | int status; | |
1196 | ||
1197 | if (!options.permit_local_command || | |
1198 | args == NULL || !*args) | |
1199 | return (1); | |
1200 | ||
1201 | if ((shell = getenv("SHELL")) == NULL) | |
1202 | shell = _PATH_BSHELL; | |
1203 | ||
1204 | pid = fork(); | |
1205 | if (pid == 0) { | |
1206 | debug3("Executing %s -c \"%s\"", shell, args); | |
1207 | execl(shell, shell, "-c", args, (char *)NULL); | |
1208 | error("Couldn't execute %s -c \"%s\": %s", | |
1209 | shell, args, strerror(errno)); | |
1210 | _exit(1); | |
1211 | } else if (pid == -1) | |
1212 | fatal("fork failed: %.100s", strerror(errno)); | |
1213 | while (waitpid(pid, &status, 0) == -1) | |
1214 | if (errno != EINTR) | |
1215 | fatal("Couldn't wait for child: %s", strerror(errno)); | |
1216 | ||
1217 | if (!WIFEXITED(status)) | |
1218 | return (1); | |
1219 | ||
1220 | return (WEXITSTATUS(status)); | |
1221 | } |