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8efc0c15 | 1 | /* |
5260325f | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
4 | * All rights reserved | |
5 | * Created: Sat Mar 18 22:15:47 1995 ylo | |
6 | * Code to connect to a remote host, and to perform the client side of the | |
7 | * login (authentication) dialog. | |
8 | */ | |
8efc0c15 | 9 | |
10 | #include "includes.h" | |
4fe2af09 | 11 | RCSID("$OpenBSD: sshconnect.c,v 1.58 2000/03/23 22:15:33 markus Exp $"); |
8efc0c15 | 12 | |
5881cd60 | 13 | #ifdef HAVE_OPENSSL |
4fe2af09 | 14 | #include <openssl/rsa.h> |
15 | #include <openssl/dsa.h> | |
5881cd60 | 16 | #include <openssl/md5.h> |
4fe2af09 | 17 | #include <openssl/bn.h> |
5881cd60 | 18 | #endif |
19 | #ifdef HAVE_SSL | |
4fe2af09 | 20 | #include <ssl/rsa.h> |
21 | #include <ssl/dsa.h> | |
5881cd60 | 22 | #include <ssl/md5.h> |
4fe2af09 | 23 | #include <ssl/bn.h> |
5881cd60 | 24 | #endif |
25 | ||
8efc0c15 | 26 | #include "xmalloc.h" |
27 | #include "rsa.h" | |
28 | #include "ssh.h" | |
29 | #include "packet.h" | |
30 | #include "authfd.h" | |
31 | #include "cipher.h" | |
32 | #include "mpaux.h" | |
33 | #include "uidswap.h" | |
34 | #include "compat.h" | |
6fa724bc | 35 | #include "readconf.h" |
4fe2af09 | 36 | #include "key.h" |
37 | #include "hostfile.h" | |
8efc0c15 | 38 | |
39 | /* Session id for the current session. */ | |
40 | unsigned char session_id[16]; | |
41 | ||
7b2ea3a1 | 42 | /* authentications supported by server */ |
43 | unsigned int supported_authentications; | |
44 | ||
57112b5a | 45 | extern Options options; |
48e671d5 | 46 | extern char *__progname; |
57112b5a | 47 | |
5260325f | 48 | /* |
49 | * Connect to the given ssh server using a proxy command. | |
50 | */ | |
8efc0c15 | 51 | int |
57112b5a | 52 | ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid, |
8efc0c15 | 53 | const char *proxy_command) |
54 | { | |
5260325f | 55 | Buffer command; |
56 | const char *cp; | |
57 | char *command_string; | |
58 | int pin[2], pout[2]; | |
59 | int pid; | |
48e671d5 | 60 | char strport[NI_MAXSERV]; |
5260325f | 61 | |
62 | /* Convert the port number into a string. */ | |
48e671d5 | 63 | snprintf(strport, sizeof strport, "%hu", port); |
5260325f | 64 | |
65 | /* Build the final command string in the buffer by making the | |
66 | appropriate substitutions to the given proxy command. */ | |
67 | buffer_init(&command); | |
68 | for (cp = proxy_command; *cp; cp++) { | |
69 | if (cp[0] == '%' && cp[1] == '%') { | |
70 | buffer_append(&command, "%", 1); | |
71 | cp++; | |
72 | continue; | |
73 | } | |
74 | if (cp[0] == '%' && cp[1] == 'h') { | |
75 | buffer_append(&command, host, strlen(host)); | |
76 | cp++; | |
77 | continue; | |
78 | } | |
79 | if (cp[0] == '%' && cp[1] == 'p') { | |
48e671d5 | 80 | buffer_append(&command, strport, strlen(strport)); |
5260325f | 81 | cp++; |
82 | continue; | |
83 | } | |
84 | buffer_append(&command, cp, 1); | |
8efc0c15 | 85 | } |
5260325f | 86 | buffer_append(&command, "\0", 1); |
87 | ||
88 | /* Get the final command string. */ | |
89 | command_string = buffer_ptr(&command); | |
90 | ||
91 | /* Create pipes for communicating with the proxy. */ | |
92 | if (pipe(pin) < 0 || pipe(pout) < 0) | |
93 | fatal("Could not create pipes to communicate with the proxy: %.100s", | |
94 | strerror(errno)); | |
95 | ||
96 | debug("Executing proxy command: %.500s", command_string); | |
97 | ||
98 | /* Fork and execute the proxy command. */ | |
99 | if ((pid = fork()) == 0) { | |
100 | char *argv[10]; | |
101 | ||
102 | /* Child. Permanently give up superuser privileges. */ | |
103 | permanently_set_uid(original_real_uid); | |
104 | ||
105 | /* Redirect stdin and stdout. */ | |
106 | close(pin[1]); | |
107 | if (pin[0] != 0) { | |
108 | if (dup2(pin[0], 0) < 0) | |
109 | perror("dup2 stdin"); | |
110 | close(pin[0]); | |
111 | } | |
112 | close(pout[0]); | |
113 | if (dup2(pout[1], 1) < 0) | |
114 | perror("dup2 stdout"); | |
115 | /* Cannot be 1 because pin allocated two descriptors. */ | |
116 | close(pout[1]); | |
117 | ||
118 | /* Stderr is left as it is so that error messages get | |
119 | printed on the user's terminal. */ | |
120 | argv[0] = "/bin/sh"; | |
121 | argv[1] = "-c"; | |
122 | argv[2] = command_string; | |
123 | argv[3] = NULL; | |
124 | ||
125 | /* Execute the proxy command. Note that we gave up any | |
126 | extra privileges above. */ | |
127 | execv("/bin/sh", argv); | |
128 | perror("/bin/sh"); | |
129 | exit(1); | |
8efc0c15 | 130 | } |
5260325f | 131 | /* Parent. */ |
132 | if (pid < 0) | |
133 | fatal("fork failed: %.100s", strerror(errno)); | |
134 | ||
135 | /* Close child side of the descriptors. */ | |
136 | close(pin[0]); | |
137 | close(pout[1]); | |
138 | ||
139 | /* Free the command name. */ | |
140 | buffer_free(&command); | |
141 | ||
142 | /* Set the connection file descriptors. */ | |
143 | packet_set_connection(pout[0], pin[1]); | |
8efc0c15 | 144 | |
5260325f | 145 | return 1; |
146 | } | |
8efc0c15 | 147 | |
5260325f | 148 | /* |
149 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
150 | */ | |
151 | int | |
48e671d5 | 152 | ssh_create_socket(uid_t original_real_uid, int privileged, int family) |
8efc0c15 | 153 | { |
5260325f | 154 | int sock; |
155 | ||
aa3378df | 156 | /* |
157 | * If we are running as root and want to connect to a privileged | |
158 | * port, bind our own socket to a privileged port. | |
159 | */ | |
5260325f | 160 | if (privileged) { |
161 | int p = IPPORT_RESERVED - 1; | |
48e671d5 | 162 | sock = rresvport_af(&p, family); |
5260325f | 163 | if (sock < 0) |
c8d54615 | 164 | error("rresvport: af=%d %.100s", family, strerror(errno)); |
165 | else | |
166 | debug("Allocated local port %d.", p); | |
5260325f | 167 | } else { |
95f1eccc | 168 | /* |
169 | * Just create an ordinary socket on arbitrary port. We use | |
170 | * the user's uid to create the socket. | |
171 | */ | |
5260325f | 172 | temporarily_use_uid(original_real_uid); |
48e671d5 | 173 | sock = socket(family, SOCK_STREAM, 0); |
5260325f | 174 | if (sock < 0) |
48e671d5 | 175 | error("socket: %.100s", strerror(errno)); |
5260325f | 176 | restore_uid(); |
177 | } | |
178 | return sock; | |
8efc0c15 | 179 | } |
180 | ||
5260325f | 181 | /* |
48e671d5 | 182 | * Opens a TCP/IP connection to the remote server on the given host. |
183 | * The address of the remote host will be returned in hostaddr. | |
184 | * If port is 0, the default port will be used. If anonymous is zero, | |
5260325f | 185 | * a privileged port will be allocated to make the connection. |
186 | * This requires super-user privileges if anonymous is false. | |
187 | * Connection_attempts specifies the maximum number of tries (one per | |
188 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
189 | * and %p substituted for host and port, respectively) to use to contact | |
190 | * the daemon. | |
191 | */ | |
192 | int | |
48e671d5 | 193 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
57112b5a | 194 | u_short port, int connection_attempts, |
5260325f | 195 | int anonymous, uid_t original_real_uid, |
196 | const char *proxy_command) | |
8efc0c15 | 197 | { |
48e671d5 | 198 | int sock = -1, attempt; |
5260325f | 199 | struct servent *sp; |
48e671d5 | 200 | struct addrinfo hints, *ai, *aitop; |
201 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
202 | int gaierr; | |
5260325f | 203 | struct linger linger; |
204 | ||
205 | debug("ssh_connect: getuid %d geteuid %d anon %d", | |
206 | (int) getuid(), (int) geteuid(), anonymous); | |
207 | ||
208 | /* Get default port if port has not been set. */ | |
209 | if (port == 0) { | |
210 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); | |
211 | if (sp) | |
212 | port = ntohs(sp->s_port); | |
213 | else | |
214 | port = SSH_DEFAULT_PORT; | |
8efc0c15 | 215 | } |
5260325f | 216 | /* If a proxy command is given, connect using it. */ |
217 | if (proxy_command != NULL) | |
218 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); | |
219 | ||
220 | /* No proxy command. */ | |
221 | ||
48e671d5 | 222 | memset(&hints, 0, sizeof(hints)); |
223 | hints.ai_family = IPv4or6; | |
224 | hints.ai_socktype = SOCK_STREAM; | |
225 | snprintf(strport, sizeof strport, "%d", port); | |
226 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) | |
227 | fatal("%s: %.100s: %s", __progname, host, | |
228 | gai_strerror(gaierr)); | |
5260325f | 229 | |
95f1eccc | 230 | /* |
231 | * Try to connect several times. On some machines, the first time | |
232 | * will sometimes fail. In general socket code appears to behave | |
233 | * quite magically on many machines. | |
234 | */ | |
5260325f | 235 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
236 | if (attempt > 0) | |
237 | debug("Trying again..."); | |
238 | ||
48e671d5 | 239 | /* Loop through addresses for this host, and try each one in |
240 | sequence until the connection succeeds. */ | |
241 | for (ai = aitop; ai; ai = ai->ai_next) { | |
242 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
243 | continue; | |
244 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
245 | ntop, sizeof(ntop), strport, sizeof(strport), | |
246 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
247 | error("ssh_connect: getnameinfo failed"); | |
248 | continue; | |
249 | } | |
250 | debug("Connecting to %.200s [%.100s] port %s.", | |
251 | host, ntop, strport); | |
252 | ||
253 | /* Create a socket for connecting. */ | |
254 | sock = ssh_create_socket(original_real_uid, | |
255 | !anonymous && geteuid() == 0 && port < IPPORT_RESERVED, | |
256 | ai->ai_family); | |
257 | if (sock < 0) | |
258 | continue; | |
259 | ||
260 | /* Connect to the host. We use the user's uid in the | |
261 | * hope that it will help with tcp_wrappers showing | |
262 | * the remote uid as root. | |
aa3378df | 263 | */ |
5260325f | 264 | temporarily_use_uid(original_real_uid); |
48e671d5 | 265 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { |
266 | /* Successful connection. */ | |
267 | memcpy(hostaddr, ai->ai_addr, sizeof(*(ai->ai_addr))); | |
5260325f | 268 | restore_uid(); |
269 | break; | |
48e671d5 | 270 | } else { |
5260325f | 271 | debug("connect: %.100s", strerror(errno)); |
272 | restore_uid(); | |
aa3378df | 273 | /* |
274 | * Close the failed socket; there appear to | |
275 | * be some problems when reusing a socket for | |
276 | * which connect() has already returned an | |
277 | * error. | |
278 | */ | |
5260325f | 279 | shutdown(sock, SHUT_RDWR); |
280 | close(sock); | |
281 | } | |
8efc0c15 | 282 | } |
48e671d5 | 283 | if (ai) |
284 | break; /* Successful connection. */ | |
8efc0c15 | 285 | |
5260325f | 286 | /* Sleep a moment before retrying. */ |
287 | sleep(1); | |
288 | } | |
48e671d5 | 289 | |
290 | freeaddrinfo(aitop); | |
291 | ||
5260325f | 292 | /* Return failure if we didn't get a successful connection. */ |
293 | if (attempt >= connection_attempts) | |
294 | return 0; | |
8efc0c15 | 295 | |
5260325f | 296 | debug("Connection established."); |
8efc0c15 | 297 | |
aa3378df | 298 | /* |
299 | * Set socket options. We would like the socket to disappear as soon | |
300 | * as it has been closed for whatever reason. | |
301 | */ | |
302 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 303 | linger.l_onoff = 1; |
304 | linger.l_linger = 5; | |
305 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
8efc0c15 | 306 | |
5260325f | 307 | /* Set the connection. */ |
308 | packet_set_connection(sock, sock); | |
8efc0c15 | 309 | |
5260325f | 310 | return 1; |
8efc0c15 | 311 | } |
312 | ||
5260325f | 313 | /* |
314 | * Checks if the user has an authentication agent, and if so, tries to | |
315 | * authenticate using the agent. | |
316 | */ | |
8efc0c15 | 317 | int |
318 | try_agent_authentication() | |
319 | { | |
5260325f | 320 | int status, type; |
321 | char *comment; | |
322 | AuthenticationConnection *auth; | |
323 | unsigned char response[16]; | |
324 | unsigned int i; | |
325 | BIGNUM *e, *n, *challenge; | |
326 | ||
327 | /* Get connection to the agent. */ | |
328 | auth = ssh_get_authentication_connection(); | |
329 | if (!auth) | |
330 | return 0; | |
331 | ||
332 | e = BN_new(); | |
333 | n = BN_new(); | |
334 | challenge = BN_new(); | |
335 | ||
336 | /* Loop through identities served by the agent. */ | |
337 | for (status = ssh_get_first_identity(auth, e, n, &comment); | |
338 | status; | |
339 | status = ssh_get_next_identity(auth, e, n, &comment)) { | |
340 | int plen, clen; | |
341 | ||
342 | /* Try this identity. */ | |
343 | debug("Trying RSA authentication via agent with '%.100s'", comment); | |
344 | xfree(comment); | |
345 | ||
346 | /* Tell the server that we are willing to authenticate using this key. */ | |
347 | packet_start(SSH_CMSG_AUTH_RSA); | |
348 | packet_put_bignum(n); | |
349 | packet_send(); | |
350 | packet_write_wait(); | |
351 | ||
352 | /* Wait for server's response. */ | |
353 | type = packet_read(&plen); | |
354 | ||
355 | /* The server sends failure if it doesn\'t like our key or | |
356 | does not support RSA authentication. */ | |
357 | if (type == SSH_SMSG_FAILURE) { | |
358 | debug("Server refused our key."); | |
359 | continue; | |
360 | } | |
361 | /* Otherwise it should have sent a challenge. */ | |
362 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
363 | packet_disconnect("Protocol error during RSA authentication: %d", | |
364 | type); | |
8efc0c15 | 365 | |
5260325f | 366 | packet_get_bignum(challenge, &clen); |
8efc0c15 | 367 | |
5260325f | 368 | packet_integrity_check(plen, clen, type); |
8efc0c15 | 369 | |
5260325f | 370 | debug("Received RSA challenge from server."); |
371 | ||
372 | /* Ask the agent to decrypt the challenge. */ | |
373 | if (!ssh_decrypt_challenge(auth, e, n, challenge, | |
374 | session_id, 1, response)) { | |
375 | /* The agent failed to authenticate this identifier although it | |
376 | advertised it supports this. Just return a wrong value. */ | |
377 | log("Authentication agent failed to decrypt challenge."); | |
378 | memset(response, 0, sizeof(response)); | |
379 | } | |
380 | debug("Sending response to RSA challenge."); | |
381 | ||
382 | /* Send the decrypted challenge back to the server. */ | |
383 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
384 | for (i = 0; i < 16; i++) | |
385 | packet_put_char(response[i]); | |
386 | packet_send(); | |
387 | packet_write_wait(); | |
388 | ||
389 | /* Wait for response from the server. */ | |
390 | type = packet_read(&plen); | |
391 | ||
392 | /* The server returns success if it accepted the authentication. */ | |
393 | if (type == SSH_SMSG_SUCCESS) { | |
394 | debug("RSA authentication accepted by server."); | |
395 | BN_clear_free(e); | |
396 | BN_clear_free(n); | |
397 | BN_clear_free(challenge); | |
398 | return 1; | |
399 | } | |
400 | /* Otherwise it should return failure. */ | |
401 | if (type != SSH_SMSG_FAILURE) | |
402 | packet_disconnect("Protocol error waiting RSA auth response: %d", | |
403 | type); | |
404 | } | |
405 | ||
406 | BN_clear_free(e); | |
407 | BN_clear_free(n); | |
408 | BN_clear_free(challenge); | |
8efc0c15 | 409 | |
5260325f | 410 | debug("RSA authentication using agent refused."); |
411 | return 0; | |
412 | } | |
8efc0c15 | 413 | |
5260325f | 414 | /* |
415 | * Computes the proper response to a RSA challenge, and sends the response to | |
416 | * the server. | |
417 | */ | |
8efc0c15 | 418 | void |
5260325f | 419 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
8efc0c15 | 420 | { |
5260325f | 421 | unsigned char buf[32], response[16]; |
422 | MD5_CTX md; | |
423 | int i, len; | |
424 | ||
425 | /* Decrypt the challenge using the private key. */ | |
426 | rsa_private_decrypt(challenge, challenge, prv); | |
427 | ||
428 | /* Compute the response. */ | |
429 | /* The response is MD5 of decrypted challenge plus session id. */ | |
430 | len = BN_num_bytes(challenge); | |
431 | if (len <= 0 || len > sizeof(buf)) | |
432 | packet_disconnect("respond_to_rsa_challenge: bad challenge length %d", | |
433 | len); | |
434 | ||
435 | memset(buf, 0, sizeof(buf)); | |
436 | BN_bn2bin(challenge, buf + sizeof(buf) - len); | |
437 | MD5_Init(&md); | |
438 | MD5_Update(&md, buf, 32); | |
439 | MD5_Update(&md, session_id, 16); | |
440 | MD5_Final(response, &md); | |
441 | ||
442 | debug("Sending response to host key RSA challenge."); | |
443 | ||
444 | /* Send the response back to the server. */ | |
445 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
446 | for (i = 0; i < 16; i++) | |
447 | packet_put_char(response[i]); | |
448 | packet_send(); | |
449 | packet_write_wait(); | |
8efc0c15 | 450 | |
5260325f | 451 | memset(buf, 0, sizeof(buf)); |
452 | memset(response, 0, sizeof(response)); | |
453 | memset(&md, 0, sizeof(md)); | |
454 | } | |
8efc0c15 | 455 | |
5260325f | 456 | /* |
457 | * Checks if the user has authentication file, and if so, tries to authenticate | |
458 | * the user using it. | |
459 | */ | |
8efc0c15 | 460 | int |
57112b5a | 461 | try_rsa_authentication(const char *authfile) |
8efc0c15 | 462 | { |
5260325f | 463 | BIGNUM *challenge; |
464 | RSA *private_key; | |
465 | RSA *public_key; | |
466 | char *passphrase, *comment; | |
467 | int type, i; | |
468 | int plen, clen; | |
469 | ||
470 | /* Try to load identification for the authentication key. */ | |
471 | public_key = RSA_new(); | |
472 | if (!load_public_key(authfile, public_key, &comment)) { | |
473 | RSA_free(public_key); | |
57112b5a | 474 | /* Could not load it. Fail. */ |
475 | return 0; | |
8efc0c15 | 476 | } |
5260325f | 477 | debug("Trying RSA authentication with key '%.100s'", comment); |
478 | ||
479 | /* Tell the server that we are willing to authenticate using this key. */ | |
480 | packet_start(SSH_CMSG_AUTH_RSA); | |
481 | packet_put_bignum(public_key->n); | |
482 | packet_send(); | |
483 | packet_write_wait(); | |
484 | ||
485 | /* We no longer need the public key. */ | |
486 | RSA_free(public_key); | |
487 | ||
488 | /* Wait for server's response. */ | |
489 | type = packet_read(&plen); | |
490 | ||
aa3378df | 491 | /* |
492 | * The server responds with failure if it doesn\'t like our key or | |
493 | * doesn\'t support RSA authentication. | |
494 | */ | |
5260325f | 495 | if (type == SSH_SMSG_FAILURE) { |
496 | debug("Server refused our key."); | |
497 | xfree(comment); | |
57112b5a | 498 | return 0; |
8efc0c15 | 499 | } |
5260325f | 500 | /* Otherwise, the server should respond with a challenge. */ |
501 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
502 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
503 | ||
504 | /* Get the challenge from the packet. */ | |
505 | challenge = BN_new(); | |
506 | packet_get_bignum(challenge, &clen); | |
507 | ||
508 | packet_integrity_check(plen, clen, type); | |
509 | ||
510 | debug("Received RSA challenge from server."); | |
511 | ||
512 | private_key = RSA_new(); | |
aa3378df | 513 | /* |
514 | * Load the private key. Try first with empty passphrase; if it | |
515 | * fails, ask for a passphrase. | |
516 | */ | |
5260325f | 517 | if (!load_private_key(authfile, "", private_key, NULL)) { |
518 | char buf[300]; | |
519 | snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ", | |
a408af76 | 520 | comment); |
5260325f | 521 | if (!options.batch_mode) |
522 | passphrase = read_passphrase(buf, 0); | |
523 | else { | |
524 | debug("Will not query passphrase for %.100s in batch mode.", | |
525 | comment); | |
526 | passphrase = xstrdup(""); | |
527 | } | |
8efc0c15 | 528 | |
5260325f | 529 | /* Load the authentication file using the pasphrase. */ |
530 | if (!load_private_key(authfile, passphrase, private_key, NULL)) { | |
531 | memset(passphrase, 0, strlen(passphrase)); | |
532 | xfree(passphrase); | |
533 | error("Bad passphrase."); | |
534 | ||
535 | /* Send a dummy response packet to avoid protocol error. */ | |
536 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
537 | for (i = 0; i < 16; i++) | |
538 | packet_put_char(0); | |
539 | packet_send(); | |
540 | packet_write_wait(); | |
541 | ||
542 | /* Expect the server to reject it... */ | |
543 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
544 | xfree(comment); | |
545 | return 0; | |
546 | } | |
547 | /* Destroy the passphrase. */ | |
548 | memset(passphrase, 0, strlen(passphrase)); | |
549 | xfree(passphrase); | |
550 | } | |
551 | /* We no longer need the comment. */ | |
552 | xfree(comment); | |
553 | ||
554 | /* Compute and send a response to the challenge. */ | |
555 | respond_to_rsa_challenge(challenge, private_key); | |
556 | ||
557 | /* Destroy the private key. */ | |
558 | RSA_free(private_key); | |
8efc0c15 | 559 | |
5260325f | 560 | /* We no longer need the challenge. */ |
561 | BN_clear_free(challenge); | |
562 | ||
563 | /* Wait for response from the server. */ | |
564 | type = packet_read(&plen); | |
565 | if (type == SSH_SMSG_SUCCESS) { | |
566 | debug("RSA authentication accepted by server."); | |
567 | return 1; | |
568 | } | |
569 | if (type != SSH_SMSG_FAILURE) | |
570 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
571 | debug("RSA authentication refused."); | |
572 | return 0; | |
573 | } | |
8efc0c15 | 574 | |
5260325f | 575 | /* |
576 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
577 | * authentication and RSA host authentication. | |
578 | */ | |
8efc0c15 | 579 | int |
5260325f | 580 | try_rhosts_rsa_authentication(const char *local_user, RSA * host_key) |
8efc0c15 | 581 | { |
5260325f | 582 | int type; |
583 | BIGNUM *challenge; | |
584 | int plen, clen; | |
585 | ||
586 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
587 | ||
588 | /* Tell the server that we are willing to authenticate using this key. */ | |
589 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
590 | packet_put_string(local_user, strlen(local_user)); | |
591 | packet_put_int(BN_num_bits(host_key->n)); | |
592 | packet_put_bignum(host_key->e); | |
593 | packet_put_bignum(host_key->n); | |
594 | packet_send(); | |
595 | packet_write_wait(); | |
596 | ||
597 | /* Wait for server's response. */ | |
598 | type = packet_read(&plen); | |
599 | ||
600 | /* The server responds with failure if it doesn't admit our | |
601 | .rhosts authentication or doesn't know our host key. */ | |
602 | if (type == SSH_SMSG_FAILURE) { | |
603 | debug("Server refused our rhosts authentication or host key."); | |
604 | return 0; | |
605 | } | |
606 | /* Otherwise, the server should respond with a challenge. */ | |
607 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
608 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
609 | ||
610 | /* Get the challenge from the packet. */ | |
611 | challenge = BN_new(); | |
612 | packet_get_bignum(challenge, &clen); | |
613 | ||
614 | packet_integrity_check(plen, clen, type); | |
615 | ||
616 | debug("Received RSA challenge for host key from server."); | |
617 | ||
618 | /* Compute a response to the challenge. */ | |
619 | respond_to_rsa_challenge(challenge, host_key); | |
620 | ||
621 | /* We no longer need the challenge. */ | |
622 | BN_clear_free(challenge); | |
623 | ||
624 | /* Wait for response from the server. */ | |
625 | type = packet_read(&plen); | |
626 | if (type == SSH_SMSG_SUCCESS) { | |
627 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
628 | return 1; | |
629 | } | |
630 | if (type != SSH_SMSG_FAILURE) | |
631 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
632 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
633 | return 0; | |
8efc0c15 | 634 | } |
635 | ||
636 | #ifdef KRB4 | |
5260325f | 637 | int |
638 | try_kerberos_authentication() | |
8efc0c15 | 639 | { |
5260325f | 640 | KTEXT_ST auth; /* Kerberos data */ |
641 | char *reply; | |
642 | char inst[INST_SZ]; | |
643 | char *realm; | |
644 | CREDENTIALS cred; | |
645 | int r, type, plen; | |
610cd5c6 | 646 | socklen_t slen; |
5260325f | 647 | Key_schedule schedule; |
648 | u_long checksum, cksum; | |
649 | MSG_DAT msg_data; | |
650 | struct sockaddr_in local, foreign; | |
651 | struct stat st; | |
652 | ||
653 | /* Don't do anything if we don't have any tickets. */ | |
654 | if (stat(tkt_string(), &st) < 0) | |
655 | return 0; | |
656 | ||
657 | strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ); | |
658 | ||
659 | realm = (char *) krb_realmofhost(get_canonical_hostname()); | |
660 | if (!realm) { | |
661 | debug("Kerberos V4: no realm for %s", get_canonical_hostname()); | |
662 | return 0; | |
663 | } | |
664 | /* This can really be anything. */ | |
665 | checksum = (u_long) getpid(); | |
666 | ||
667 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); | |
668 | if (r != KSUCCESS) { | |
669 | debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]); | |
670 | return 0; | |
671 | } | |
672 | /* Get session key to decrypt the server's reply with. */ | |
673 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
674 | if (r != KSUCCESS) { | |
675 | debug("get_cred failed: %s", krb_err_txt[r]); | |
676 | return 0; | |
677 | } | |
678 | des_key_sched((des_cblock *) cred.session, schedule); | |
679 | ||
680 | /* Send authentication info to server. */ | |
681 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
682 | packet_put_string((char *) auth.dat, auth.length); | |
683 | packet_send(); | |
684 | packet_write_wait(); | |
685 | ||
686 | /* Zero the buffer. */ | |
687 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
688 | ||
610cd5c6 | 689 | slen = sizeof(local); |
5260325f | 690 | memset(&local, 0, sizeof(local)); |
691 | if (getsockname(packet_get_connection_in(), | |
610cd5c6 | 692 | (struct sockaddr *) & local, &slen) < 0) |
5260325f | 693 | debug("getsockname failed: %s", strerror(errno)); |
694 | ||
610cd5c6 | 695 | slen = sizeof(foreign); |
5260325f | 696 | memset(&foreign, 0, sizeof(foreign)); |
697 | if (getpeername(packet_get_connection_in(), | |
610cd5c6 | 698 | (struct sockaddr *) & foreign, &slen) < 0) { |
5260325f | 699 | debug("getpeername failed: %s", strerror(errno)); |
700 | fatal_cleanup(); | |
701 | } | |
702 | /* Get server reply. */ | |
703 | type = packet_read(&plen); | |
704 | switch (type) { | |
705 | case SSH_SMSG_FAILURE: | |
706 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
707 | debug("Kerberos V4 authentication failed."); | |
708 | return 0; | |
709 | break; | |
710 | ||
711 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
712 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
713 | debug("Kerberos V4 authentication accepted."); | |
714 | ||
715 | /* Get server's response. */ | |
716 | reply = packet_get_string((unsigned int *) &auth.length); | |
717 | memcpy(auth.dat, reply, auth.length); | |
718 | xfree(reply); | |
719 | ||
720 | packet_integrity_check(plen, 4 + auth.length, type); | |
721 | ||
aa3378df | 722 | /* |
723 | * If his response isn't properly encrypted with the session | |
724 | * key, and the decrypted checksum fails to match, he's | |
725 | * bogus. Bail out. | |
726 | */ | |
5260325f | 727 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, |
728 | &foreign, &local, &msg_data); | |
729 | if (r != KSUCCESS) { | |
730 | debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]); | |
731 | packet_disconnect("Kerberos V4 challenge failed!"); | |
732 | } | |
733 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
734 | (void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum)); | |
735 | cksum = ntohl(cksum); | |
736 | ||
737 | /* If it matches, we're golden. */ | |
738 | if (cksum == checksum + 1) { | |
739 | debug("Kerberos V4 challenge successful."); | |
740 | return 1; | |
741 | } else | |
742 | packet_disconnect("Kerberos V4 challenge failed!"); | |
743 | break; | |
744 | ||
745 | default: | |
746 | packet_disconnect("Protocol error on Kerberos V4 response: %d", type); | |
747 | } | |
748 | return 0; | |
8efc0c15 | 749 | } |
5260325f | 750 | |
8efc0c15 | 751 | #endif /* KRB4 */ |
752 | ||
753 | #ifdef AFS | |
5260325f | 754 | int |
755 | send_kerberos_tgt() | |
8efc0c15 | 756 | { |
5260325f | 757 | CREDENTIALS *creds; |
758 | char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; | |
759 | int r, type, plen; | |
610cd5c6 | 760 | char buffer[8192]; |
5260325f | 761 | struct stat st; |
762 | ||
763 | /* Don't do anything if we don't have any tickets. */ | |
764 | if (stat(tkt_string(), &st) < 0) | |
765 | return 0; | |
766 | ||
767 | creds = xmalloc(sizeof(*creds)); | |
768 | ||
769 | if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) { | |
770 | debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]); | |
771 | return 0; | |
772 | } | |
773 | if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) { | |
774 | debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]); | |
775 | return 0; | |
776 | } | |
777 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { | |
778 | debug("Kerberos V4 ticket expired: %s", TKT_FILE); | |
779 | return 0; | |
780 | } | |
610cd5c6 | 781 | creds_to_radix(creds, (unsigned char *)buffer); |
5260325f | 782 | xfree(creds); |
783 | ||
784 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
610cd5c6 | 785 | packet_put_string(buffer, strlen(buffer)); |
5260325f | 786 | packet_send(); |
787 | packet_write_wait(); | |
788 | ||
789 | type = packet_read(&plen); | |
790 | ||
791 | if (type == SSH_SMSG_FAILURE) | |
792 | debug("Kerberos TGT for realm %s rejected.", prealm); | |
793 | else if (type != SSH_SMSG_SUCCESS) | |
794 | packet_disconnect("Protocol error on Kerberos TGT response: %d", type); | |
795 | ||
796 | return 1; | |
8efc0c15 | 797 | } |
798 | ||
5260325f | 799 | void |
800 | send_afs_tokens(void) | |
8efc0c15 | 801 | { |
5260325f | 802 | CREDENTIALS creds; |
803 | struct ViceIoctl parms; | |
804 | struct ClearToken ct; | |
805 | int i, type, len, plen; | |
806 | char buf[2048], *p, *server_cell; | |
610cd5c6 | 807 | char buffer[8192]; |
5260325f | 808 | |
809 | /* Move over ktc_GetToken, here's something leaner. */ | |
810 | for (i = 0; i < 100; i++) { /* just in case */ | |
811 | parms.in = (char *) &i; | |
812 | parms.in_size = sizeof(i); | |
813 | parms.out = buf; | |
814 | parms.out_size = sizeof(buf); | |
815 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
816 | break; | |
817 | p = buf; | |
818 | ||
819 | /* Get secret token. */ | |
820 | memcpy(&creds.ticket_st.length, p, sizeof(unsigned int)); | |
821 | if (creds.ticket_st.length > MAX_KTXT_LEN) | |
822 | break; | |
823 | p += sizeof(unsigned int); | |
824 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); | |
825 | p += creds.ticket_st.length; | |
826 | ||
827 | /* Get clear token. */ | |
828 | memcpy(&len, p, sizeof(len)); | |
829 | if (len != sizeof(struct ClearToken)) | |
830 | break; | |
831 | p += sizeof(len); | |
832 | memcpy(&ct, p, len); | |
833 | p += len; | |
834 | p += sizeof(len); /* primary flag */ | |
835 | server_cell = p; | |
836 | ||
837 | /* Flesh out our credentials. */ | |
838 | strlcpy(creds.service, "afs", sizeof creds.service); | |
839 | creds.instance[0] = '\0'; | |
840 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
841 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
842 | creds.issue_date = ct.BeginTimestamp; | |
843 | creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp); | |
844 | creds.kvno = ct.AuthHandle; | |
845 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
846 | creds.pinst[0] = '\0'; | |
847 | ||
848 | /* Encode token, ship it off. */ | |
610cd5c6 | 849 | if (!creds_to_radix(&creds, (unsigned char*) buffer)) |
5260325f | 850 | break; |
851 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
610cd5c6 | 852 | packet_put_string(buffer, strlen(buffer)); |
5260325f | 853 | packet_send(); |
854 | packet_write_wait(); | |
855 | ||
856 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
857 | Victor? */ | |
858 | type = packet_read(&plen); | |
859 | ||
860 | if (type == SSH_SMSG_FAILURE) | |
861 | debug("AFS token for cell %s rejected.", server_cell); | |
862 | else if (type != SSH_SMSG_SUCCESS) | |
863 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
864 | } | |
8efc0c15 | 865 | } |
8efc0c15 | 866 | |
5260325f | 867 | #endif /* AFS */ |
8efc0c15 | 868 | |
57112b5a | 869 | /* |
870 | * Tries to authenticate with any string-based challenge/response system. | |
871 | * Note that the client code is not tied to s/key or TIS. | |
872 | */ | |
873 | int | |
874 | try_skey_authentication() | |
875 | { | |
610cd5c6 | 876 | int type, i; |
877 | int payload_len; | |
878 | unsigned int clen; | |
57112b5a | 879 | char *challenge, *response; |
880 | ||
881 | debug("Doing skey authentication."); | |
882 | ||
883 | /* request a challenge */ | |
884 | packet_start(SSH_CMSG_AUTH_TIS); | |
885 | packet_send(); | |
886 | packet_write_wait(); | |
887 | ||
888 | type = packet_read(&payload_len); | |
889 | if (type != SSH_SMSG_FAILURE && | |
890 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
891 | packet_disconnect("Protocol error: got %d in response " | |
892 | "to skey-auth", type); | |
893 | } | |
894 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
895 | debug("No challenge for skey authentication."); | |
896 | return 0; | |
897 | } | |
610cd5c6 | 898 | challenge = packet_get_string(&clen); |
899 | packet_integrity_check(payload_len, (4 + clen), type); | |
57112b5a | 900 | if (options.cipher == SSH_CIPHER_NONE) |
901 | log("WARNING: Encryption is disabled! " | |
902 | "Reponse will be transmitted in clear text."); | |
903 | fprintf(stderr, "%s\n", challenge); | |
c8d54615 | 904 | xfree(challenge); |
57112b5a | 905 | fflush(stderr); |
906 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
907 | if (i != 0) | |
908 | error("Permission denied, please try again."); | |
909 | response = read_passphrase("Response: ", 0); | |
910 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); | |
911 | packet_put_string(response, strlen(response)); | |
912 | memset(response, 0, strlen(response)); | |
913 | xfree(response); | |
914 | packet_send(); | |
915 | packet_write_wait(); | |
916 | type = packet_read(&payload_len); | |
917 | if (type == SSH_SMSG_SUCCESS) | |
918 | return 1; | |
919 | if (type != SSH_SMSG_FAILURE) | |
920 | packet_disconnect("Protocol error: got %d in response " | |
921 | "to skey-auth-reponse", type); | |
922 | } | |
923 | /* failure */ | |
924 | return 0; | |
925 | } | |
926 | ||
927 | /* | |
928 | * Tries to authenticate with plain passwd authentication. | |
929 | */ | |
930 | int | |
931 | try_password_authentication(char *prompt) | |
932 | { | |
933 | int type, i, payload_len; | |
934 | char *password; | |
935 | ||
936 | debug("Doing password authentication."); | |
937 | if (options.cipher == SSH_CIPHER_NONE) | |
938 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
939 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
940 | if (i != 0) | |
941 | error("Permission denied, please try again."); | |
942 | password = read_passphrase(prompt, 0); | |
943 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
944 | packet_put_string(password, strlen(password)); | |
945 | memset(password, 0, strlen(password)); | |
946 | xfree(password); | |
947 | packet_send(); | |
948 | packet_write_wait(); | |
949 | ||
950 | type = packet_read(&payload_len); | |
951 | if (type == SSH_SMSG_SUCCESS) | |
952 | return 1; | |
953 | if (type != SSH_SMSG_FAILURE) | |
954 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
955 | } | |
956 | /* failure */ | |
957 | return 0; | |
958 | } | |
959 | ||
5260325f | 960 | /* |
961 | * Waits for the server identification string, and sends our own | |
962 | * identification string. | |
963 | */ | |
964 | void | |
965 | ssh_exchange_identification() | |
8efc0c15 | 966 | { |
5260325f | 967 | char buf[256], remote_version[256]; /* must be same size! */ |
968 | int remote_major, remote_minor, i; | |
969 | int connection_in = packet_get_connection_in(); | |
970 | int connection_out = packet_get_connection_out(); | |
5260325f | 971 | |
972 | /* Read other side\'s version identification. */ | |
973 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
c8d54615 | 974 | int len = read(connection_in, &buf[i], 1); |
975 | if (len < 0) | |
5260325f | 976 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); |
c8d54615 | 977 | if (len != 1) |
978 | fatal("ssh_exchange_identification: Connection closed by remote host"); | |
5260325f | 979 | if (buf[i] == '\r') { |
980 | buf[i] = '\n'; | |
981 | buf[i + 1] = 0; | |
982 | break; | |
983 | } | |
984 | if (buf[i] == '\n') { | |
985 | buf[i + 1] = 0; | |
986 | break; | |
987 | } | |
8efc0c15 | 988 | } |
5260325f | 989 | buf[sizeof(buf) - 1] = 0; |
990 | ||
aa3378df | 991 | /* |
992 | * Check that the versions match. In future this might accept | |
993 | * several versions and set appropriate flags to handle them. | |
994 | */ | |
5260325f | 995 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
996 | remote_version) != 3) | |
997 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
998 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
999 | remote_major, remote_minor, remote_version); | |
1000 | ||
1001 | /* Check if the remote protocol version is too old. */ | |
1002 | if (remote_major == 1 && remote_minor < 3) | |
1003 | fatal("Remote machine has too old SSH software version."); | |
1004 | ||
1005 | /* We speak 1.3, too. */ | |
1006 | if (remote_major == 1 && remote_minor == 3) { | |
1007 | enable_compat13(); | |
7b2ea3a1 | 1008 | if (options.forward_agent) { |
1009 | log("Agent forwarding disabled for protocol 1.3"); | |
5260325f | 1010 | options.forward_agent = 0; |
1011 | } | |
8efc0c15 | 1012 | } |
8efc0c15 | 1013 | #if 0 |
aa3378df | 1014 | /* |
1015 | * Removed for now, to permit compatibility with latter versions. The | |
1016 | * server will reject our version and disconnect if it doesn't | |
1017 | * support it. | |
1018 | */ | |
5260325f | 1019 | if (remote_major != PROTOCOL_MAJOR) |
1020 | fatal("Protocol major versions differ: %d vs. %d", | |
1021 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 1022 | #endif |
1023 | ||
5260325f | 1024 | /* Send our own protocol version identification. */ |
1025 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
a408af76 | 1026 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); |
1027 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) | |
5260325f | 1028 | fatal("write: %.100s", strerror(errno)); |
8efc0c15 | 1029 | } |
1030 | ||
1031 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
1032 | ||
5260325f | 1033 | int |
1034 | read_yes_or_no(const char *prompt, int defval) | |
8efc0c15 | 1035 | { |
5260325f | 1036 | char buf[1024]; |
1037 | FILE *f; | |
1038 | int retval = -1; | |
1039 | ||
1040 | if (isatty(0)) | |
1041 | f = stdin; | |
1042 | else | |
1043 | f = fopen("/dev/tty", "rw"); | |
1044 | ||
1045 | if (f == NULL) | |
1046 | return 0; | |
1047 | ||
1048 | fflush(stdout); | |
1049 | ||
1050 | while (1) { | |
1051 | fprintf(stderr, "%s", prompt); | |
1052 | if (fgets(buf, sizeof(buf), f) == NULL) { | |
1053 | /* Print a newline (the prompt probably didn\'t have one). */ | |
1054 | fprintf(stderr, "\n"); | |
1055 | strlcpy(buf, "no", sizeof buf); | |
1056 | } | |
1057 | /* Remove newline from response. */ | |
1058 | if (strchr(buf, '\n')) | |
1059 | *strchr(buf, '\n') = 0; | |
1060 | ||
1061 | if (buf[0] == 0) | |
1062 | retval = defval; | |
1063 | if (strcmp(buf, "yes") == 0) | |
1064 | retval = 1; | |
1065 | if (strcmp(buf, "no") == 0) | |
1066 | retval = 0; | |
1067 | ||
1068 | if (retval != -1) { | |
1069 | if (f != stdin) | |
1070 | fclose(f); | |
1071 | return retval; | |
1072 | } | |
8efc0c15 | 1073 | } |
8efc0c15 | 1074 | } |
1075 | ||
5260325f | 1076 | /* |
95f1eccc | 1077 | * check whether the supplied host key is valid, return only if ok. |
5260325f | 1078 | */ |
95f1eccc | 1079 | |
5260325f | 1080 | void |
4fe2af09 | 1081 | check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) |
8efc0c15 | 1082 | { |
4fe2af09 | 1083 | Key *file_key; |
95f1eccc | 1084 | char *ip = NULL; |
5260325f | 1085 | char hostline[1000], *hostp; |
5260325f | 1086 | HostStatus host_status; |
1087 | HostStatus ip_status; | |
48e671d5 | 1088 | int local = 0, host_ip_differ = 0; |
20af321f | 1089 | int salen; |
48e671d5 | 1090 | char ntop[NI_MAXHOST]; |
1091 | ||
1092 | /* | |
1093 | * Force accepting of the host key for loopback/localhost. The | |
1094 | * problem is that if the home directory is NFS-mounted to multiple | |
1095 | * machines, localhost will refer to a different machine in each of | |
1096 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
1097 | * essentially disables host authentication for localhost; however, | |
1098 | * this is probably not a real problem. | |
1099 | */ | |
1100 | switch (hostaddr->sa_family) { | |
1101 | case AF_INET: | |
1102 | local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; | |
20af321f | 1103 | salen = sizeof(struct sockaddr_in); |
48e671d5 | 1104 | break; |
1105 | case AF_INET6: | |
1106 | local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
20af321f | 1107 | salen = sizeof(struct sockaddr_in6); |
48e671d5 | 1108 | break; |
1109 | default: | |
1110 | local = 0; | |
20af321f | 1111 | salen = sizeof(struct sockaddr_storage); |
48e671d5 | 1112 | break; |
1113 | } | |
1114 | if (local) { | |
1115 | debug("Forcing accepting of host key for loopback/localhost."); | |
1116 | return; | |
1117 | } | |
5260325f | 1118 | |
57112b5a | 1119 | /* |
1120 | * Turn off check_host_ip for proxy connects, since | |
1121 | * we don't have the remote ip-address | |
1122 | */ | |
1123 | if (options.proxy_command != NULL && options.check_host_ip) | |
1124 | options.check_host_ip = 0; | |
1125 | ||
48e671d5 | 1126 | if (options.check_host_ip) { |
20af321f | 1127 | if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop), |
48e671d5 | 1128 | NULL, 0, NI_NUMERICHOST) != 0) |
1129 | fatal("check_host_key: getnameinfo failed"); | |
1130 | ip = xstrdup(ntop); | |
1131 | } | |
5260325f | 1132 | |
95f1eccc | 1133 | /* |
1134 | * Store the host key from the known host file in here so that we can | |
1135 | * compare it with the key for the IP address. | |
1136 | */ | |
4fe2af09 | 1137 | file_key = key_new(host_key->type); |
5260325f | 1138 | |
aa3378df | 1139 | /* |
1140 | * Check if the host key is present in the user\'s list of known | |
1141 | * hosts or in the systemwide list. | |
1142 | */ | |
4fe2af09 | 1143 | host_status = check_host_in_hostfile(options.user_hostfile, host, host_key, file_key); |
5260325f | 1144 | if (host_status == HOST_NEW) |
4fe2af09 | 1145 | host_status = check_host_in_hostfile(options.system_hostfile, host, host_key, file_key); |
aa3378df | 1146 | /* |
1147 | * Also perform check for the ip address, skip the check if we are | |
1148 | * localhost or the hostname was an ip address to begin with | |
1149 | */ | |
5260325f | 1150 | if (options.check_host_ip && !local && strcmp(host, ip)) { |
4fe2af09 | 1151 | Key *ip_key = key_new(host_key->type); |
1152 | ip_status = check_host_in_hostfile(options.user_hostfile, ip, host_key, ip_key); | |
5260325f | 1153 | |
1154 | if (ip_status == HOST_NEW) | |
4fe2af09 | 1155 | ip_status = check_host_in_hostfile(options.system_hostfile, ip, host_key, ip_key); |
5260325f | 1156 | if (host_status == HOST_CHANGED && |
4fe2af09 | 1157 | (ip_status != HOST_CHANGED || !key_equal(ip_key, file_key))) |
5260325f | 1158 | host_ip_differ = 1; |
1159 | ||
4fe2af09 | 1160 | key_free(ip_key); |
5260325f | 1161 | } else |
1162 | ip_status = host_status; | |
1163 | ||
4fe2af09 | 1164 | key_free(file_key); |
5260325f | 1165 | |
1166 | switch (host_status) { | |
1167 | case HOST_OK: | |
1168 | /* The host is known and the key matches. */ | |
1169 | debug("Host '%.200s' is known and matches the host key.", host); | |
1170 | if (options.check_host_ip) { | |
1171 | if (ip_status == HOST_NEW) { | |
4fe2af09 | 1172 | if (!add_host_to_hostfile(options.user_hostfile, ip, host_key)) |
5260325f | 1173 | log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).", |
1174 | ip, options.user_hostfile); | |
1175 | else | |
1176 | log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.", | |
1177 | ip); | |
1178 | } else if (ip_status != HOST_OK) | |
1179 | log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'", | |
1180 | host, ip); | |
1181 | } | |
1182 | break; | |
1183 | case HOST_NEW: | |
1184 | /* The host is new. */ | |
1185 | if (options.strict_host_key_checking == 1) { | |
1186 | /* User has requested strict host key checking. We will not add the host key | |
1187 | automatically. The only alternative left is to abort. */ | |
1188 | fatal("No host key is known for %.200s and you have requested strict checking.", host); | |
1189 | } else if (options.strict_host_key_checking == 2) { | |
1190 | /* The default */ | |
1191 | char prompt[1024]; | |
4fe2af09 | 1192 | char *fp = key_fingerprint(host_key); |
5260325f | 1193 | snprintf(prompt, sizeof(prompt), |
a408af76 | 1194 | "The authenticity of host '%.200s' can't be established.\n" |
4fe2af09 | 1195 | "Key fingerprint is %s.\n" |
a408af76 | 1196 | "Are you sure you want to continue connecting (yes/no)? ", |
4fe2af09 | 1197 | host, fp); |
5260325f | 1198 | if (!read_yes_or_no(prompt, -1)) |
1199 | fatal("Aborted by user!\n"); | |
1200 | } | |
1201 | if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) { | |
1202 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); | |
1203 | hostp = hostline; | |
1204 | } else | |
1205 | hostp = host; | |
1206 | ||
1207 | /* If not in strict mode, add the key automatically to the local known_hosts file. */ | |
4fe2af09 | 1208 | if (!add_host_to_hostfile(options.user_hostfile, hostp, host_key)) |
5260325f | 1209 | log("Failed to add the host to the list of known hosts (%.500s).", |
1210 | options.user_hostfile); | |
1211 | else | |
1212 | log("Warning: Permanently added '%.200s' to the list of known hosts.", | |
1213 | hostp); | |
1214 | break; | |
1215 | case HOST_CHANGED: | |
1216 | if (options.check_host_ip && host_ip_differ) { | |
1217 | char *msg; | |
1218 | if (ip_status == HOST_NEW) | |
1219 | msg = "is unknown"; | |
1220 | else if (ip_status == HOST_OK) | |
1221 | msg = "is unchanged"; | |
1222 | else | |
1223 | msg = "has a different value"; | |
1224 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1225 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
1226 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1227 | error("The host key for %s has changed,", host); | |
1228 | error("and the key for the according IP address %s", ip); | |
1229 | error("%s. This could either mean that", msg); | |
1230 | error("DNS SPOOFING is happening or the IP address for the host"); | |
1231 | error("and its host key have changed at the same time"); | |
1232 | } | |
1233 | /* The host key has changed. */ | |
1234 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
ae2f7af7 | 1235 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
5260325f | 1236 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
1237 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1238 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1239 | error("It is also possible that the host key has just been changed."); | |
1240 | error("Please contact your system administrator."); | |
1241 | error("Add correct host key in %.100s to get rid of this message.", | |
1242 | options.user_hostfile); | |
1243 | ||
aa3378df | 1244 | /* |
1245 | * If strict host key checking is in use, the user will have | |
1246 | * to edit the key manually and we can only abort. | |
1247 | */ | |
5260325f | 1248 | if (options.strict_host_key_checking) |
1249 | fatal("Host key for %.200s has changed and you have requested strict checking.", host); | |
1250 | ||
aa3378df | 1251 | /* |
1252 | * If strict host key checking has not been requested, allow | |
1253 | * the connection but without password authentication or | |
1254 | * agent forwarding. | |
1255 | */ | |
5260325f | 1256 | if (options.password_authentication) { |
1257 | error("Password authentication is disabled to avoid trojan horses."); | |
1258 | options.password_authentication = 0; | |
1259 | } | |
1260 | if (options.forward_agent) { | |
1261 | error("Agent forwarding is disabled to avoid trojan horses."); | |
1262 | options.forward_agent = 0; | |
1263 | } | |
aa3378df | 1264 | /* |
1265 | * XXX Should permit the user to change to use the new id. | |
1266 | * This could be done by converting the host key to an | |
1267 | * identifying sentence, tell that the host identifies itself | |
1268 | * by that sentence, and ask the user if he/she whishes to | |
1269 | * accept the authentication. | |
1270 | */ | |
5260325f | 1271 | break; |
1272 | } | |
5260325f | 1273 | if (options.check_host_ip) |
1274 | xfree(ip); | |
95f1eccc | 1275 | } |
4fe2af09 | 1276 | void |
1277 | check_rsa_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key) | |
1278 | { | |
1279 | Key k; | |
1280 | k.type = KEY_RSA; | |
1281 | k.rsa = host_key; | |
1282 | check_host_key(host, hostaddr, &k); | |
1283 | } | |
95f1eccc | 1284 | |
1285 | /* | |
7b2ea3a1 | 1286 | * SSH1 key exchange |
95f1eccc | 1287 | */ |
1288 | void | |
7b2ea3a1 | 1289 | ssh_kex(char *host, struct sockaddr *hostaddr) |
95f1eccc | 1290 | { |
7b2ea3a1 | 1291 | int i; |
95f1eccc | 1292 | BIGNUM *key; |
1293 | RSA *host_key; | |
1294 | RSA *public_key; | |
1295 | int bits, rbits; | |
1296 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
7b2ea3a1 | 1297 | unsigned char cookie[8]; |
1298 | unsigned int supported_ciphers; | |
95f1eccc | 1299 | unsigned int server_flags, client_flags; |
1300 | int payload_len, clen, sum_len = 0; | |
1301 | u_int32_t rand = 0; | |
1302 | ||
95f1eccc | 1303 | debug("Waiting for server public key."); |
1304 | ||
1305 | /* Wait for a public key packet from the server. */ | |
1306 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
1307 | ||
7b2ea3a1 | 1308 | /* Get cookie from the packet. */ |
95f1eccc | 1309 | for (i = 0; i < 8; i++) |
7b2ea3a1 | 1310 | cookie[i] = packet_get_char(); |
95f1eccc | 1311 | |
1312 | /* Get the public key. */ | |
1313 | public_key = RSA_new(); | |
1314 | bits = packet_get_int();/* bits */ | |
1315 | public_key->e = BN_new(); | |
1316 | packet_get_bignum(public_key->e, &clen); | |
1317 | sum_len += clen; | |
1318 | public_key->n = BN_new(); | |
1319 | packet_get_bignum(public_key->n, &clen); | |
1320 | sum_len += clen; | |
1321 | ||
1322 | rbits = BN_num_bits(public_key->n); | |
1323 | if (bits != rbits) { | |
1324 | log("Warning: Server lies about size of server public key: " | |
1325 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1326 | log("Warning: This may be due to an old implementation of ssh."); | |
1327 | } | |
1328 | /* Get the host key. */ | |
1329 | host_key = RSA_new(); | |
1330 | bits = packet_get_int();/* bits */ | |
1331 | host_key->e = BN_new(); | |
1332 | packet_get_bignum(host_key->e, &clen); | |
1333 | sum_len += clen; | |
1334 | host_key->n = BN_new(); | |
1335 | packet_get_bignum(host_key->n, &clen); | |
1336 | sum_len += clen; | |
1337 | ||
1338 | rbits = BN_num_bits(host_key->n); | |
1339 | if (bits != rbits) { | |
1340 | log("Warning: Server lies about size of server host key: " | |
1341 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1342 | log("Warning: This may be due to an old implementation of ssh."); | |
1343 | } | |
1344 | ||
1345 | /* Get protocol flags. */ | |
1346 | server_flags = packet_get_int(); | |
1347 | packet_set_protocol_flags(server_flags); | |
1348 | ||
1349 | supported_ciphers = packet_get_int(); | |
1350 | supported_authentications = packet_get_int(); | |
1351 | ||
1352 | debug("Received server public key (%d bits) and host key (%d bits).", | |
1353 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
1354 | ||
1355 | packet_integrity_check(payload_len, | |
1356 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
1357 | SSH_SMSG_PUBLIC_KEY); | |
1358 | ||
4fe2af09 | 1359 | check_rsa_host_key(host, hostaddr, host_key); |
95f1eccc | 1360 | |
1361 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; | |
1362 | ||
7b2ea3a1 | 1363 | compute_session_id(session_id, cookie, host_key->n, public_key->n); |
5260325f | 1364 | |
1365 | /* Generate a session key. */ | |
1366 | arc4random_stir(); | |
1367 | ||
aa3378df | 1368 | /* |
1369 | * Generate an encryption key for the session. The key is a 256 bit | |
1370 | * random number, interpreted as a 32-byte key, with the least | |
1371 | * significant 8 bits being the first byte of the key. | |
1372 | */ | |
5260325f | 1373 | for (i = 0; i < 32; i++) { |
1374 | if (i % 4 == 0) | |
1375 | rand = arc4random(); | |
1376 | session_key[i] = rand & 0xff; | |
1377 | rand >>= 8; | |
1378 | } | |
1379 | ||
aa3378df | 1380 | /* |
1381 | * According to the protocol spec, the first byte of the session key | |
1382 | * is the highest byte of the integer. The session key is xored with | |
1383 | * the first 16 bytes of the session id. | |
1384 | */ | |
5260325f | 1385 | key = BN_new(); |
1386 | BN_set_word(key, 0); | |
1387 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1388 | BN_lshift(key, key, 8); | |
1389 | if (i < 16) | |
1390 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1391 | else | |
1392 | BN_add_word(key, session_key[i]); | |
1393 | } | |
1394 | ||
aa3378df | 1395 | /* |
1396 | * Encrypt the integer using the public key and host key of the | |
1397 | * server (key with smaller modulus first). | |
1398 | */ | |
5260325f | 1399 | if (BN_cmp(public_key->n, host_key->n) < 0) { |
1400 | /* Public key has smaller modulus. */ | |
1401 | if (BN_num_bits(host_key->n) < | |
1402 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1403 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1404 | "SSH_KEY_BITS_RESERVED %d", | |
1405 | BN_num_bits(host_key->n), | |
1406 | BN_num_bits(public_key->n), | |
1407 | SSH_KEY_BITS_RESERVED); | |
1408 | } | |
1409 | rsa_public_encrypt(key, key, public_key); | |
1410 | rsa_public_encrypt(key, key, host_key); | |
1411 | } else { | |
1412 | /* Host key has smaller modulus (or they are equal). */ | |
1413 | if (BN_num_bits(public_key->n) < | |
1414 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1415 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1416 | "SSH_KEY_BITS_RESERVED %d", | |
1417 | BN_num_bits(public_key->n), | |
1418 | BN_num_bits(host_key->n), | |
1419 | SSH_KEY_BITS_RESERVED); | |
1420 | } | |
1421 | rsa_public_encrypt(key, key, host_key); | |
1422 | rsa_public_encrypt(key, key, public_key); | |
1423 | } | |
1424 | ||
7b2ea3a1 | 1425 | /* Destroy the public keys since we no longer need them. */ |
1426 | RSA_free(public_key); | |
1427 | RSA_free(host_key); | |
1428 | ||
5260325f | 1429 | if (options.cipher == SSH_CIPHER_NOT_SET) { |
1430 | if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default)) | |
1431 | options.cipher = ssh_cipher_default; | |
1432 | else { | |
1433 | debug("Cipher %s not supported, using %.100s instead.", | |
1434 | cipher_name(ssh_cipher_default), | |
1435 | cipher_name(SSH_FALLBACK_CIPHER)); | |
1436 | options.cipher = SSH_FALLBACK_CIPHER; | |
1437 | } | |
1438 | } | |
1439 | /* Check that the selected cipher is supported. */ | |
1440 | if (!(supported_ciphers & (1 << options.cipher))) | |
1441 | fatal("Selected cipher type %.100s not supported by server.", | |
1442 | cipher_name(options.cipher)); | |
1443 | ||
1444 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1445 | ||
1446 | /* Send the encrypted session key to the server. */ | |
1447 | packet_start(SSH_CMSG_SESSION_KEY); | |
1448 | packet_put_char(options.cipher); | |
1449 | ||
7b2ea3a1 | 1450 | /* Send the cookie back to the server. */ |
5260325f | 1451 | for (i = 0; i < 8; i++) |
7b2ea3a1 | 1452 | packet_put_char(cookie[i]); |
5260325f | 1453 | |
7b2ea3a1 | 1454 | /* Send and destroy the encrypted encryption key integer. */ |
5260325f | 1455 | packet_put_bignum(key); |
7b2ea3a1 | 1456 | BN_clear_free(key); |
5260325f | 1457 | |
1458 | /* Send protocol flags. */ | |
95f1eccc | 1459 | packet_put_int(client_flags); |
5260325f | 1460 | |
1461 | /* Send the packet now. */ | |
8efc0c15 | 1462 | packet_send(); |
1463 | packet_write_wait(); | |
5260325f | 1464 | |
5260325f | 1465 | debug("Sent encrypted session key."); |
1466 | ||
1467 | /* Set the encryption key. */ | |
1468 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1469 | ||
1470 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1471 | memset(session_key, 0, sizeof(session_key)); | |
1472 | ||
aa3378df | 1473 | /* |
1474 | * Expect a success message from the server. Note that this message | |
1475 | * will be received in encrypted form. | |
1476 | */ | |
5260325f | 1477 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); |
1478 | ||
1479 | debug("Received encrypted confirmation."); | |
7b2ea3a1 | 1480 | } |
1481 | ||
1482 | /* | |
1483 | * Authenticate user | |
1484 | */ | |
1485 | void | |
1486 | ssh_userauth(int host_key_valid, RSA *own_host_key, | |
1487 | uid_t original_real_uid, char *host) | |
1488 | { | |
1489 | int i, type; | |
1490 | int payload_len; | |
1491 | struct passwd *pw; | |
1492 | const char *server_user, *local_user; | |
1493 | ||
1494 | /* Get local user name. Use it as server user if no user name was given. */ | |
1495 | pw = getpwuid(original_real_uid); | |
1496 | if (!pw) | |
1497 | fatal("User id %d not found from user database.", original_real_uid); | |
1498 | local_user = xstrdup(pw->pw_name); | |
1499 | server_user = options.user ? options.user : local_user; | |
5260325f | 1500 | |
1501 | /* Send the name of the user to log in as on the server. */ | |
1502 | packet_start(SSH_CMSG_USER); | |
1503 | packet_put_string(server_user, strlen(server_user)); | |
1504 | packet_send(); | |
1505 | packet_write_wait(); | |
1506 | ||
aa3378df | 1507 | /* |
1508 | * The server should respond with success if no authentication is | |
1509 | * needed (the user has no password). Otherwise the server responds | |
1510 | * with failure. | |
1511 | */ | |
8efc0c15 | 1512 | type = packet_read(&payload_len); |
5260325f | 1513 | |
1514 | /* check whether the connection was accepted without authentication. */ | |
8efc0c15 | 1515 | if (type == SSH_SMSG_SUCCESS) |
5260325f | 1516 | return; |
8efc0c15 | 1517 | if (type != SSH_SMSG_FAILURE) |
5260325f | 1518 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", |
1519 | type); | |
1520 | ||
1521 | #ifdef AFS | |
1522 | /* Try Kerberos tgt passing if the server supports it. */ | |
1523 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1524 | options.kerberos_tgt_passing) { | |
1525 | if (options.cipher == SSH_CIPHER_NONE) | |
1526 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1527 | (void) send_kerberos_tgt(); | |
1528 | } | |
1529 | /* Try AFS token passing if the server supports it. */ | |
1530 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1531 | options.afs_token_passing && k_hasafs()) { | |
1532 | if (options.cipher == SSH_CIPHER_NONE) | |
1533 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1534 | send_afs_tokens(); | |
1535 | } | |
1536 | #endif /* AFS */ | |
8efc0c15 | 1537 | |
5260325f | 1538 | #ifdef KRB4 |
1539 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1540 | options.kerberos_authentication) { | |
1541 | debug("Trying Kerberos authentication."); | |
1542 | if (try_kerberos_authentication()) { | |
1543 | /* The server should respond with success or failure. */ | |
1544 | type = packet_read(&payload_len); | |
1545 | if (type == SSH_SMSG_SUCCESS) | |
1546 | return; | |
1547 | if (type != SSH_SMSG_FAILURE) | |
1548 | packet_disconnect("Protocol error: got %d in response to Kerberos auth", type); | |
1549 | } | |
1550 | } | |
1551 | #endif /* KRB4 */ | |
1552 | ||
aa3378df | 1553 | /* |
1554 | * Use rhosts authentication if running in privileged socket and we | |
1555 | * do not wish to remain anonymous. | |
1556 | */ | |
5260325f | 1557 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && |
1558 | options.rhosts_authentication) { | |
1559 | debug("Trying rhosts authentication."); | |
1560 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
1561 | packet_put_string(local_user, strlen(local_user)); | |
1562 | packet_send(); | |
1563 | packet_write_wait(); | |
1564 | ||
1565 | /* The server should respond with success or failure. */ | |
1566 | type = packet_read(&payload_len); | |
1567 | if (type == SSH_SMSG_SUCCESS) | |
1568 | return; | |
1569 | if (type != SSH_SMSG_FAILURE) | |
1570 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1571 | type); | |
1572 | } | |
aa3378df | 1573 | /* |
1574 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1575 | * authentication. | |
1576 | */ | |
5260325f | 1577 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && |
1578 | options.rhosts_rsa_authentication && host_key_valid) { | |
1579 | if (try_rhosts_rsa_authentication(local_user, own_host_key)) | |
1580 | return; | |
1581 | } | |
1582 | /* Try RSA authentication if the server supports it. */ | |
1583 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1584 | options.rsa_authentication) { | |
aa3378df | 1585 | /* |
1586 | * Try RSA authentication using the authentication agent. The | |
1587 | * agent is tried first because no passphrase is needed for | |
1588 | * it, whereas identity files may require passphrases. | |
1589 | */ | |
5260325f | 1590 | if (try_agent_authentication()) |
1591 | return; | |
1592 | ||
1593 | /* Try RSA authentication for each identity. */ | |
1594 | for (i = 0; i < options.num_identity_files; i++) | |
57112b5a | 1595 | if (try_rsa_authentication(options.identity_files[i])) |
5260325f | 1596 | return; |
1597 | } | |
1598 | /* Try skey authentication if the server supports it. */ | |
1599 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && | |
1600 | options.skey_authentication && !options.batch_mode) { | |
57112b5a | 1601 | if (try_skey_authentication()) |
1602 | return; | |
5260325f | 1603 | } |
1604 | /* Try password authentication if the server supports it. */ | |
1605 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1606 | options.password_authentication && !options.batch_mode) { | |
1607 | char prompt[80]; | |
a408af76 | 1608 | |
57112b5a | 1609 | snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
a408af76 | 1610 | server_user, host); |
57112b5a | 1611 | if (try_password_authentication(prompt)) |
1612 | return; | |
5260325f | 1613 | } |
1614 | /* All authentication methods have failed. Exit with an error message. */ | |
1615 | fatal("Permission denied."); | |
1616 | /* NOTREACHED */ | |
8efc0c15 | 1617 | } |
7b2ea3a1 | 1618 | /* |
1619 | * Starts a dialog with the server, and authenticates the current user on the | |
1620 | * server. This does not need any extra privileges. The basic connection | |
1621 | * to the server must already have been established before this is called. | |
1622 | * If login fails, this function prints an error and never returns. | |
1623 | * This function does not require super-user privileges. | |
1624 | */ | |
1625 | void | |
1626 | ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost, | |
1627 | struct sockaddr *hostaddr, uid_t original_real_uid) | |
1628 | { | |
1629 | char *host, *cp; | |
1630 | ||
1631 | /* Convert the user-supplied hostname into all lowercase. */ | |
1632 | host = xstrdup(orighost); | |
1633 | for (cp = host; *cp; cp++) | |
1634 | if (isupper(*cp)) | |
1635 | *cp = tolower(*cp); | |
1636 | ||
1637 | /* Exchange protocol version identification strings with the server. */ | |
1638 | ssh_exchange_identification(); | |
1639 | ||
1640 | /* Put the connection into non-blocking mode. */ | |
1641 | packet_set_nonblocking(); | |
1642 | ||
1643 | supported_authentications = 0; | |
1644 | /* key exchange */ | |
1645 | ssh_kex(host, hostaddr); | |
1646 | if (supported_authentications == 0) | |
1647 | fatal("supported_authentications == 0."); | |
4fe2af09 | 1648 | |
7b2ea3a1 | 1649 | /* authenticate user */ |
1650 | ssh_userauth(host_key_valid, own_host_key, original_real_uid, host); | |
1651 | } |