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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" | |
11 | RCSID("$Id$"); | |
12 | ||
5881cd60 | 13 | #ifdef HAVE_OPENSSL |
8efc0c15 | 14 | #include <openssl/bn.h> |
5881cd60 | 15 | #include <openssl/md5.h> |
16 | #endif | |
17 | #ifdef HAVE_SSL | |
18 | #include <ssl/bn.h> | |
19 | #include <ssl/md5.h> | |
20 | #endif | |
21 | ||
8efc0c15 | 22 | #include "xmalloc.h" |
23 | #include "rsa.h" | |
24 | #include "ssh.h" | |
25 | #include "packet.h" | |
26 | #include "authfd.h" | |
27 | #include "cipher.h" | |
28 | #include "mpaux.h" | |
29 | #include "uidswap.h" | |
30 | #include "compat.h" | |
6fa724bc | 31 | #include "readconf.h" |
2bd61362 | 32 | #include "fingerprint.h" |
8efc0c15 | 33 | |
34 | /* Session id for the current session. */ | |
35 | unsigned char session_id[16]; | |
36 | ||
57112b5a | 37 | extern Options options; |
38 | ||
5260325f | 39 | /* |
40 | * Connect to the given ssh server using a proxy command. | |
41 | */ | |
8efc0c15 | 42 | int |
57112b5a | 43 | ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid, |
8efc0c15 | 44 | const char *proxy_command) |
45 | { | |
5260325f | 46 | Buffer command; |
47 | const char *cp; | |
48 | char *command_string; | |
49 | int pin[2], pout[2]; | |
50 | int pid; | |
51 | char portstring[100]; | |
52 | ||
53 | /* Convert the port number into a string. */ | |
57112b5a | 54 | snprintf(portstring, sizeof portstring, "%hu", port); |
5260325f | 55 | |
56 | /* Build the final command string in the buffer by making the | |
57 | appropriate substitutions to the given proxy command. */ | |
58 | buffer_init(&command); | |
59 | for (cp = proxy_command; *cp; cp++) { | |
60 | if (cp[0] == '%' && cp[1] == '%') { | |
61 | buffer_append(&command, "%", 1); | |
62 | cp++; | |
63 | continue; | |
64 | } | |
65 | if (cp[0] == '%' && cp[1] == 'h') { | |
66 | buffer_append(&command, host, strlen(host)); | |
67 | cp++; | |
68 | continue; | |
69 | } | |
70 | if (cp[0] == '%' && cp[1] == 'p') { | |
71 | buffer_append(&command, portstring, strlen(portstring)); | |
72 | cp++; | |
73 | continue; | |
74 | } | |
75 | buffer_append(&command, cp, 1); | |
8efc0c15 | 76 | } |
5260325f | 77 | buffer_append(&command, "\0", 1); |
78 | ||
79 | /* Get the final command string. */ | |
80 | command_string = buffer_ptr(&command); | |
81 | ||
82 | /* Create pipes for communicating with the proxy. */ | |
83 | if (pipe(pin) < 0 || pipe(pout) < 0) | |
84 | fatal("Could not create pipes to communicate with the proxy: %.100s", | |
85 | strerror(errno)); | |
86 | ||
87 | debug("Executing proxy command: %.500s", command_string); | |
88 | ||
89 | /* Fork and execute the proxy command. */ | |
90 | if ((pid = fork()) == 0) { | |
91 | char *argv[10]; | |
92 | ||
93 | /* Child. Permanently give up superuser privileges. */ | |
94 | permanently_set_uid(original_real_uid); | |
95 | ||
96 | /* Redirect stdin and stdout. */ | |
97 | close(pin[1]); | |
98 | if (pin[0] != 0) { | |
99 | if (dup2(pin[0], 0) < 0) | |
100 | perror("dup2 stdin"); | |
101 | close(pin[0]); | |
102 | } | |
103 | close(pout[0]); | |
104 | if (dup2(pout[1], 1) < 0) | |
105 | perror("dup2 stdout"); | |
106 | /* Cannot be 1 because pin allocated two descriptors. */ | |
107 | close(pout[1]); | |
108 | ||
109 | /* Stderr is left as it is so that error messages get | |
110 | printed on the user's terminal. */ | |
111 | argv[0] = "/bin/sh"; | |
112 | argv[1] = "-c"; | |
113 | argv[2] = command_string; | |
114 | argv[3] = NULL; | |
115 | ||
116 | /* Execute the proxy command. Note that we gave up any | |
117 | extra privileges above. */ | |
118 | execv("/bin/sh", argv); | |
119 | perror("/bin/sh"); | |
120 | exit(1); | |
8efc0c15 | 121 | } |
5260325f | 122 | /* Parent. */ |
123 | if (pid < 0) | |
124 | fatal("fork failed: %.100s", strerror(errno)); | |
125 | ||
126 | /* Close child side of the descriptors. */ | |
127 | close(pin[0]); | |
128 | close(pout[1]); | |
129 | ||
130 | /* Free the command name. */ | |
131 | buffer_free(&command); | |
132 | ||
133 | /* Set the connection file descriptors. */ | |
134 | packet_set_connection(pout[0], pin[1]); | |
8efc0c15 | 135 | |
5260325f | 136 | return 1; |
137 | } | |
8efc0c15 | 138 | |
5260325f | 139 | /* |
140 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
141 | */ | |
142 | int | |
143 | ssh_create_socket(uid_t original_real_uid, int privileged) | |
8efc0c15 | 144 | { |
5260325f | 145 | int sock; |
146 | ||
aa3378df | 147 | /* |
148 | * If we are running as root and want to connect to a privileged | |
149 | * port, bind our own socket to a privileged port. | |
150 | */ | |
5260325f | 151 | if (privileged) { |
152 | int p = IPPORT_RESERVED - 1; | |
153 | ||
154 | sock = rresvport(&p); | |
155 | if (sock < 0) | |
156 | fatal("rresvport: %.100s", strerror(errno)); | |
157 | debug("Allocated local port %d.", p); | |
158 | } else { | |
159 | /* Just create an ordinary socket on arbitrary port. We | |
160 | use the user's uid to create the socket. */ | |
161 | temporarily_use_uid(original_real_uid); | |
162 | sock = socket(AF_INET, SOCK_STREAM, 0); | |
163 | if (sock < 0) | |
164 | fatal("socket: %.100s", strerror(errno)); | |
165 | restore_uid(); | |
166 | } | |
167 | return sock; | |
8efc0c15 | 168 | } |
169 | ||
5260325f | 170 | /* |
171 | * Opens a TCP/IP connection to the remote server on the given host. If | |
172 | * port is 0, the default port will be used. If anonymous is zero, | |
173 | * a privileged port will be allocated to make the connection. | |
174 | * This requires super-user privileges if anonymous is false. | |
175 | * Connection_attempts specifies the maximum number of tries (one per | |
176 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
177 | * and %p substituted for host and port, respectively) to use to contact | |
178 | * the daemon. | |
179 | */ | |
180 | int | |
181 | ssh_connect(const char *host, struct sockaddr_in * hostaddr, | |
57112b5a | 182 | u_short port, int connection_attempts, |
5260325f | 183 | int anonymous, uid_t original_real_uid, |
184 | const char *proxy_command) | |
8efc0c15 | 185 | { |
5260325f | 186 | int sock = -1, attempt, i; |
187 | int on = 1; | |
188 | struct servent *sp; | |
189 | struct hostent *hp; | |
190 | struct linger linger; | |
191 | ||
192 | debug("ssh_connect: getuid %d geteuid %d anon %d", | |
193 | (int) getuid(), (int) geteuid(), anonymous); | |
194 | ||
195 | /* Get default port if port has not been set. */ | |
196 | if (port == 0) { | |
197 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); | |
198 | if (sp) | |
199 | port = ntohs(sp->s_port); | |
200 | else | |
201 | port = SSH_DEFAULT_PORT; | |
8efc0c15 | 202 | } |
5260325f | 203 | /* If a proxy command is given, connect using it. */ |
204 | if (proxy_command != NULL) | |
205 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); | |
206 | ||
207 | /* No proxy command. */ | |
208 | ||
209 | /* No host lookup made yet. */ | |
210 | hp = NULL; | |
211 | ||
212 | /* Try to connect several times. On some machines, the first time | |
213 | will sometimes fail. In general socket code appears to behave | |
214 | quite magically on many machines. */ | |
215 | for (attempt = 0; attempt < connection_attempts; attempt++) { | |
216 | if (attempt > 0) | |
217 | debug("Trying again..."); | |
218 | ||
219 | /* Try to parse the host name as a numeric inet address. */ | |
220 | memset(hostaddr, 0, sizeof(hostaddr)); | |
221 | hostaddr->sin_family = AF_INET; | |
222 | hostaddr->sin_port = htons(port); | |
223 | hostaddr->sin_addr.s_addr = inet_addr(host); | |
224 | if ((hostaddr->sin_addr.s_addr & 0xffffffff) != 0xffffffff) { | |
225 | /* Valid numeric IP address */ | |
226 | debug("Connecting to %.100s port %d.", | |
227 | inet_ntoa(hostaddr->sin_addr), port); | |
228 | ||
229 | /* Create a socket. */ | |
230 | sock = ssh_create_socket(original_real_uid, | |
231 | !anonymous && geteuid() == 0 && | |
232 | port < IPPORT_RESERVED); | |
233 | ||
aa3378df | 234 | /* |
235 | * Connect to the host. We use the user's uid in the | |
236 | * hope that it will help with the problems of | |
237 | * tcp_wrappers showing the remote uid as root. | |
238 | */ | |
5260325f | 239 | temporarily_use_uid(original_real_uid); |
240 | if (connect(sock, (struct sockaddr *) hostaddr, sizeof(*hostaddr)) | |
241 | >= 0) { | |
242 | /* Successful connect. */ | |
243 | restore_uid(); | |
244 | break; | |
245 | } | |
246 | debug("connect: %.100s", strerror(errno)); | |
247 | restore_uid(); | |
248 | ||
249 | /* Destroy the failed socket. */ | |
250 | shutdown(sock, SHUT_RDWR); | |
251 | close(sock); | |
252 | } else { | |
253 | /* Not a valid numeric inet address. */ | |
254 | /* Map host name to an address. */ | |
255 | if (!hp) | |
256 | hp = gethostbyname(host); | |
257 | if (!hp) | |
258 | fatal("Bad host name: %.100s", host); | |
259 | if (!hp->h_addr_list[0]) | |
260 | fatal("Host does not have an IP address: %.100s", host); | |
261 | ||
262 | /* Loop through addresses for this host, and try | |
263 | each one in sequence until the connection | |
264 | succeeds. */ | |
265 | for (i = 0; hp->h_addr_list[i]; i++) { | |
266 | /* Set the address to connect to. */ | |
267 | hostaddr->sin_family = hp->h_addrtype; | |
268 | memcpy(&hostaddr->sin_addr, hp->h_addr_list[i], | |
269 | sizeof(hostaddr->sin_addr)); | |
270 | ||
271 | debug("Connecting to %.200s [%.100s] port %d.", | |
272 | host, inet_ntoa(hostaddr->sin_addr), port); | |
273 | ||
274 | /* Create a socket for connecting. */ | |
275 | sock = ssh_create_socket(original_real_uid, | |
276 | !anonymous && geteuid() == 0 && | |
277 | port < IPPORT_RESERVED); | |
278 | ||
aa3378df | 279 | /* |
280 | * Connect to the host. We use the user's | |
281 | * uid in the hope that it will help with | |
282 | * tcp_wrappers showing the remote uid as | |
283 | * root. | |
284 | */ | |
5260325f | 285 | temporarily_use_uid(original_real_uid); |
286 | if (connect(sock, (struct sockaddr *) hostaddr, | |
287 | sizeof(*hostaddr)) >= 0) { | |
288 | /* Successful connection. */ | |
289 | restore_uid(); | |
290 | break; | |
291 | } | |
292 | debug("connect: %.100s", strerror(errno)); | |
293 | restore_uid(); | |
294 | ||
aa3378df | 295 | /* |
296 | * Close the failed socket; there appear to | |
297 | * be some problems when reusing a socket for | |
298 | * which connect() has already returned an | |
299 | * error. | |
300 | */ | |
5260325f | 301 | shutdown(sock, SHUT_RDWR); |
302 | close(sock); | |
303 | } | |
304 | if (hp->h_addr_list[i]) | |
305 | break; /* Successful connection. */ | |
8efc0c15 | 306 | } |
8efc0c15 | 307 | |
5260325f | 308 | /* Sleep a moment before retrying. */ |
309 | sleep(1); | |
310 | } | |
311 | /* Return failure if we didn't get a successful connection. */ | |
312 | if (attempt >= connection_attempts) | |
313 | return 0; | |
8efc0c15 | 314 | |
5260325f | 315 | debug("Connection established."); |
8efc0c15 | 316 | |
aa3378df | 317 | /* |
318 | * Set socket options. We would like the socket to disappear as soon | |
319 | * as it has been closed for whatever reason. | |
320 | */ | |
321 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 322 | setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void *) &on, sizeof(on)); |
323 | linger.l_onoff = 1; | |
324 | linger.l_linger = 5; | |
325 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
8efc0c15 | 326 | |
5260325f | 327 | /* Set the connection. */ |
328 | packet_set_connection(sock, sock); | |
8efc0c15 | 329 | |
5260325f | 330 | return 1; |
8efc0c15 | 331 | } |
332 | ||
5260325f | 333 | /* |
334 | * Checks if the user has an authentication agent, and if so, tries to | |
335 | * authenticate using the agent. | |
336 | */ | |
8efc0c15 | 337 | int |
338 | try_agent_authentication() | |
339 | { | |
5260325f | 340 | int status, type; |
341 | char *comment; | |
342 | AuthenticationConnection *auth; | |
343 | unsigned char response[16]; | |
344 | unsigned int i; | |
345 | BIGNUM *e, *n, *challenge; | |
346 | ||
347 | /* Get connection to the agent. */ | |
348 | auth = ssh_get_authentication_connection(); | |
349 | if (!auth) | |
350 | return 0; | |
351 | ||
352 | e = BN_new(); | |
353 | n = BN_new(); | |
354 | challenge = BN_new(); | |
355 | ||
356 | /* Loop through identities served by the agent. */ | |
357 | for (status = ssh_get_first_identity(auth, e, n, &comment); | |
358 | status; | |
359 | status = ssh_get_next_identity(auth, e, n, &comment)) { | |
360 | int plen, clen; | |
361 | ||
362 | /* Try this identity. */ | |
363 | debug("Trying RSA authentication via agent with '%.100s'", comment); | |
364 | xfree(comment); | |
365 | ||
366 | /* Tell the server that we are willing to authenticate using this key. */ | |
367 | packet_start(SSH_CMSG_AUTH_RSA); | |
368 | packet_put_bignum(n); | |
369 | packet_send(); | |
370 | packet_write_wait(); | |
371 | ||
372 | /* Wait for server's response. */ | |
373 | type = packet_read(&plen); | |
374 | ||
375 | /* The server sends failure if it doesn\'t like our key or | |
376 | does not support RSA authentication. */ | |
377 | if (type == SSH_SMSG_FAILURE) { | |
378 | debug("Server refused our key."); | |
379 | continue; | |
380 | } | |
381 | /* Otherwise it should have sent a challenge. */ | |
382 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
383 | packet_disconnect("Protocol error during RSA authentication: %d", | |
384 | type); | |
8efc0c15 | 385 | |
5260325f | 386 | packet_get_bignum(challenge, &clen); |
8efc0c15 | 387 | |
5260325f | 388 | packet_integrity_check(plen, clen, type); |
8efc0c15 | 389 | |
5260325f | 390 | debug("Received RSA challenge from server."); |
391 | ||
392 | /* Ask the agent to decrypt the challenge. */ | |
393 | if (!ssh_decrypt_challenge(auth, e, n, challenge, | |
394 | session_id, 1, response)) { | |
395 | /* The agent failed to authenticate this identifier although it | |
396 | advertised it supports this. Just return a wrong value. */ | |
397 | log("Authentication agent failed to decrypt challenge."); | |
398 | memset(response, 0, sizeof(response)); | |
399 | } | |
400 | debug("Sending response to RSA challenge."); | |
401 | ||
402 | /* Send the decrypted challenge back to the server. */ | |
403 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
404 | for (i = 0; i < 16; i++) | |
405 | packet_put_char(response[i]); | |
406 | packet_send(); | |
407 | packet_write_wait(); | |
408 | ||
409 | /* Wait for response from the server. */ | |
410 | type = packet_read(&plen); | |
411 | ||
412 | /* The server returns success if it accepted the authentication. */ | |
413 | if (type == SSH_SMSG_SUCCESS) { | |
414 | debug("RSA authentication accepted by server."); | |
415 | BN_clear_free(e); | |
416 | BN_clear_free(n); | |
417 | BN_clear_free(challenge); | |
418 | return 1; | |
419 | } | |
420 | /* Otherwise it should return failure. */ | |
421 | if (type != SSH_SMSG_FAILURE) | |
422 | packet_disconnect("Protocol error waiting RSA auth response: %d", | |
423 | type); | |
424 | } | |
425 | ||
426 | BN_clear_free(e); | |
427 | BN_clear_free(n); | |
428 | BN_clear_free(challenge); | |
8efc0c15 | 429 | |
5260325f | 430 | debug("RSA authentication using agent refused."); |
431 | return 0; | |
432 | } | |
8efc0c15 | 433 | |
5260325f | 434 | /* |
435 | * Computes the proper response to a RSA challenge, and sends the response to | |
436 | * the server. | |
437 | */ | |
8efc0c15 | 438 | void |
5260325f | 439 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
8efc0c15 | 440 | { |
5260325f | 441 | unsigned char buf[32], response[16]; |
442 | MD5_CTX md; | |
443 | int i, len; | |
444 | ||
445 | /* Decrypt the challenge using the private key. */ | |
446 | rsa_private_decrypt(challenge, challenge, prv); | |
447 | ||
448 | /* Compute the response. */ | |
449 | /* The response is MD5 of decrypted challenge plus session id. */ | |
450 | len = BN_num_bytes(challenge); | |
451 | if (len <= 0 || len > sizeof(buf)) | |
452 | packet_disconnect("respond_to_rsa_challenge: bad challenge length %d", | |
453 | len); | |
454 | ||
455 | memset(buf, 0, sizeof(buf)); | |
456 | BN_bn2bin(challenge, buf + sizeof(buf) - len); | |
457 | MD5_Init(&md); | |
458 | MD5_Update(&md, buf, 32); | |
459 | MD5_Update(&md, session_id, 16); | |
460 | MD5_Final(response, &md); | |
461 | ||
462 | debug("Sending response to host key RSA challenge."); | |
463 | ||
464 | /* Send the response back to the server. */ | |
465 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
466 | for (i = 0; i < 16; i++) | |
467 | packet_put_char(response[i]); | |
468 | packet_send(); | |
469 | packet_write_wait(); | |
8efc0c15 | 470 | |
5260325f | 471 | memset(buf, 0, sizeof(buf)); |
472 | memset(response, 0, sizeof(response)); | |
473 | memset(&md, 0, sizeof(md)); | |
474 | } | |
8efc0c15 | 475 | |
5260325f | 476 | /* |
477 | * Checks if the user has authentication file, and if so, tries to authenticate | |
478 | * the user using it. | |
479 | */ | |
8efc0c15 | 480 | int |
57112b5a | 481 | try_rsa_authentication(const char *authfile) |
8efc0c15 | 482 | { |
5260325f | 483 | BIGNUM *challenge; |
484 | RSA *private_key; | |
485 | RSA *public_key; | |
486 | char *passphrase, *comment; | |
487 | int type, i; | |
488 | int plen, clen; | |
489 | ||
490 | /* Try to load identification for the authentication key. */ | |
491 | public_key = RSA_new(); | |
492 | if (!load_public_key(authfile, public_key, &comment)) { | |
493 | RSA_free(public_key); | |
57112b5a | 494 | /* Could not load it. Fail. */ |
495 | return 0; | |
8efc0c15 | 496 | } |
5260325f | 497 | debug("Trying RSA authentication with key '%.100s'", comment); |
498 | ||
499 | /* Tell the server that we are willing to authenticate using this key. */ | |
500 | packet_start(SSH_CMSG_AUTH_RSA); | |
501 | packet_put_bignum(public_key->n); | |
502 | packet_send(); | |
503 | packet_write_wait(); | |
504 | ||
505 | /* We no longer need the public key. */ | |
506 | RSA_free(public_key); | |
507 | ||
508 | /* Wait for server's response. */ | |
509 | type = packet_read(&plen); | |
510 | ||
aa3378df | 511 | /* |
512 | * The server responds with failure if it doesn\'t like our key or | |
513 | * doesn\'t support RSA authentication. | |
514 | */ | |
5260325f | 515 | if (type == SSH_SMSG_FAILURE) { |
516 | debug("Server refused our key."); | |
517 | xfree(comment); | |
57112b5a | 518 | return 0; |
8efc0c15 | 519 | } |
5260325f | 520 | /* Otherwise, the server should respond with a challenge. */ |
521 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
522 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
523 | ||
524 | /* Get the challenge from the packet. */ | |
525 | challenge = BN_new(); | |
526 | packet_get_bignum(challenge, &clen); | |
527 | ||
528 | packet_integrity_check(plen, clen, type); | |
529 | ||
530 | debug("Received RSA challenge from server."); | |
531 | ||
532 | private_key = RSA_new(); | |
aa3378df | 533 | /* |
534 | * Load the private key. Try first with empty passphrase; if it | |
535 | * fails, ask for a passphrase. | |
536 | */ | |
5260325f | 537 | if (!load_private_key(authfile, "", private_key, NULL)) { |
538 | char buf[300]; | |
539 | snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ", | |
a408af76 | 540 | comment); |
5260325f | 541 | if (!options.batch_mode) |
542 | passphrase = read_passphrase(buf, 0); | |
543 | else { | |
544 | debug("Will not query passphrase for %.100s in batch mode.", | |
545 | comment); | |
546 | passphrase = xstrdup(""); | |
547 | } | |
8efc0c15 | 548 | |
5260325f | 549 | /* Load the authentication file using the pasphrase. */ |
550 | if (!load_private_key(authfile, passphrase, private_key, NULL)) { | |
551 | memset(passphrase, 0, strlen(passphrase)); | |
552 | xfree(passphrase); | |
553 | error("Bad passphrase."); | |
554 | ||
555 | /* Send a dummy response packet to avoid protocol error. */ | |
556 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
557 | for (i = 0; i < 16; i++) | |
558 | packet_put_char(0); | |
559 | packet_send(); | |
560 | packet_write_wait(); | |
561 | ||
562 | /* Expect the server to reject it... */ | |
563 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
564 | xfree(comment); | |
565 | return 0; | |
566 | } | |
567 | /* Destroy the passphrase. */ | |
568 | memset(passphrase, 0, strlen(passphrase)); | |
569 | xfree(passphrase); | |
570 | } | |
571 | /* We no longer need the comment. */ | |
572 | xfree(comment); | |
573 | ||
574 | /* Compute and send a response to the challenge. */ | |
575 | respond_to_rsa_challenge(challenge, private_key); | |
576 | ||
577 | /* Destroy the private key. */ | |
578 | RSA_free(private_key); | |
8efc0c15 | 579 | |
5260325f | 580 | /* We no longer need the challenge. */ |
581 | BN_clear_free(challenge); | |
582 | ||
583 | /* Wait for response from the server. */ | |
584 | type = packet_read(&plen); | |
585 | if (type == SSH_SMSG_SUCCESS) { | |
586 | debug("RSA authentication accepted by server."); | |
587 | return 1; | |
588 | } | |
589 | if (type != SSH_SMSG_FAILURE) | |
590 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
591 | debug("RSA authentication refused."); | |
592 | return 0; | |
593 | } | |
8efc0c15 | 594 | |
5260325f | 595 | /* |
596 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
597 | * authentication and RSA host authentication. | |
598 | */ | |
8efc0c15 | 599 | int |
5260325f | 600 | try_rhosts_rsa_authentication(const char *local_user, RSA * host_key) |
8efc0c15 | 601 | { |
5260325f | 602 | int type; |
603 | BIGNUM *challenge; | |
604 | int plen, clen; | |
605 | ||
606 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
607 | ||
608 | /* Tell the server that we are willing to authenticate using this key. */ | |
609 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
610 | packet_put_string(local_user, strlen(local_user)); | |
611 | packet_put_int(BN_num_bits(host_key->n)); | |
612 | packet_put_bignum(host_key->e); | |
613 | packet_put_bignum(host_key->n); | |
614 | packet_send(); | |
615 | packet_write_wait(); | |
616 | ||
617 | /* Wait for server's response. */ | |
618 | type = packet_read(&plen); | |
619 | ||
620 | /* The server responds with failure if it doesn't admit our | |
621 | .rhosts authentication or doesn't know our host key. */ | |
622 | if (type == SSH_SMSG_FAILURE) { | |
623 | debug("Server refused our rhosts authentication or host key."); | |
624 | return 0; | |
625 | } | |
626 | /* Otherwise, the server should respond with a challenge. */ | |
627 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
628 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
629 | ||
630 | /* Get the challenge from the packet. */ | |
631 | challenge = BN_new(); | |
632 | packet_get_bignum(challenge, &clen); | |
633 | ||
634 | packet_integrity_check(plen, clen, type); | |
635 | ||
636 | debug("Received RSA challenge for host key from server."); | |
637 | ||
638 | /* Compute a response to the challenge. */ | |
639 | respond_to_rsa_challenge(challenge, host_key); | |
640 | ||
641 | /* We no longer need the challenge. */ | |
642 | BN_clear_free(challenge); | |
643 | ||
644 | /* Wait for response from the server. */ | |
645 | type = packet_read(&plen); | |
646 | if (type == SSH_SMSG_SUCCESS) { | |
647 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
648 | return 1; | |
649 | } | |
650 | if (type != SSH_SMSG_FAILURE) | |
651 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
652 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
653 | return 0; | |
8efc0c15 | 654 | } |
655 | ||
656 | #ifdef KRB4 | |
5260325f | 657 | int |
658 | try_kerberos_authentication() | |
8efc0c15 | 659 | { |
5260325f | 660 | KTEXT_ST auth; /* Kerberos data */ |
661 | char *reply; | |
662 | char inst[INST_SZ]; | |
663 | char *realm; | |
664 | CREDENTIALS cred; | |
665 | int r, type, plen; | |
666 | Key_schedule schedule; | |
667 | u_long checksum, cksum; | |
668 | MSG_DAT msg_data; | |
669 | struct sockaddr_in local, foreign; | |
670 | struct stat st; | |
671 | ||
672 | /* Don't do anything if we don't have any tickets. */ | |
673 | if (stat(tkt_string(), &st) < 0) | |
674 | return 0; | |
675 | ||
676 | strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ); | |
677 | ||
678 | realm = (char *) krb_realmofhost(get_canonical_hostname()); | |
679 | if (!realm) { | |
680 | debug("Kerberos V4: no realm for %s", get_canonical_hostname()); | |
681 | return 0; | |
682 | } | |
683 | /* This can really be anything. */ | |
684 | checksum = (u_long) getpid(); | |
685 | ||
686 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); | |
687 | if (r != KSUCCESS) { | |
688 | debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]); | |
689 | return 0; | |
690 | } | |
691 | /* Get session key to decrypt the server's reply with. */ | |
692 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
693 | if (r != KSUCCESS) { | |
694 | debug("get_cred failed: %s", krb_err_txt[r]); | |
695 | return 0; | |
696 | } | |
697 | des_key_sched((des_cblock *) cred.session, schedule); | |
698 | ||
699 | /* Send authentication info to server. */ | |
700 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
701 | packet_put_string((char *) auth.dat, auth.length); | |
702 | packet_send(); | |
703 | packet_write_wait(); | |
704 | ||
705 | /* Zero the buffer. */ | |
706 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
707 | ||
708 | r = sizeof(local); | |
709 | memset(&local, 0, sizeof(local)); | |
710 | if (getsockname(packet_get_connection_in(), | |
711 | (struct sockaddr *) & local, &r) < 0) | |
712 | debug("getsockname failed: %s", strerror(errno)); | |
713 | ||
714 | r = sizeof(foreign); | |
715 | memset(&foreign, 0, sizeof(foreign)); | |
716 | if (getpeername(packet_get_connection_in(), | |
717 | (struct sockaddr *) & foreign, &r) < 0) { | |
718 | debug("getpeername failed: %s", strerror(errno)); | |
719 | fatal_cleanup(); | |
720 | } | |
721 | /* Get server reply. */ | |
722 | type = packet_read(&plen); | |
723 | switch (type) { | |
724 | case SSH_SMSG_FAILURE: | |
725 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
726 | debug("Kerberos V4 authentication failed."); | |
727 | return 0; | |
728 | break; | |
729 | ||
730 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
731 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
732 | debug("Kerberos V4 authentication accepted."); | |
733 | ||
734 | /* Get server's response. */ | |
735 | reply = packet_get_string((unsigned int *) &auth.length); | |
736 | memcpy(auth.dat, reply, auth.length); | |
737 | xfree(reply); | |
738 | ||
739 | packet_integrity_check(plen, 4 + auth.length, type); | |
740 | ||
aa3378df | 741 | /* |
742 | * If his response isn't properly encrypted with the session | |
743 | * key, and the decrypted checksum fails to match, he's | |
744 | * bogus. Bail out. | |
745 | */ | |
5260325f | 746 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, |
747 | &foreign, &local, &msg_data); | |
748 | if (r != KSUCCESS) { | |
749 | debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]); | |
750 | packet_disconnect("Kerberos V4 challenge failed!"); | |
751 | } | |
752 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
753 | (void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum)); | |
754 | cksum = ntohl(cksum); | |
755 | ||
756 | /* If it matches, we're golden. */ | |
757 | if (cksum == checksum + 1) { | |
758 | debug("Kerberos V4 challenge successful."); | |
759 | return 1; | |
760 | } else | |
761 | packet_disconnect("Kerberos V4 challenge failed!"); | |
762 | break; | |
763 | ||
764 | default: | |
765 | packet_disconnect("Protocol error on Kerberos V4 response: %d", type); | |
766 | } | |
767 | return 0; | |
8efc0c15 | 768 | } |
5260325f | 769 | |
8efc0c15 | 770 | #endif /* KRB4 */ |
771 | ||
772 | #ifdef AFS | |
5260325f | 773 | int |
774 | send_kerberos_tgt() | |
8efc0c15 | 775 | { |
5260325f | 776 | CREDENTIALS *creds; |
777 | char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; | |
778 | int r, type, plen; | |
779 | unsigned char buffer[8192]; | |
780 | struct stat st; | |
781 | ||
782 | /* Don't do anything if we don't have any tickets. */ | |
783 | if (stat(tkt_string(), &st) < 0) | |
784 | return 0; | |
785 | ||
786 | creds = xmalloc(sizeof(*creds)); | |
787 | ||
788 | if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) { | |
789 | debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]); | |
790 | return 0; | |
791 | } | |
792 | if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) { | |
793 | debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]); | |
794 | return 0; | |
795 | } | |
796 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { | |
797 | debug("Kerberos V4 ticket expired: %s", TKT_FILE); | |
798 | return 0; | |
799 | } | |
800 | creds_to_radix(creds, buffer); | |
801 | xfree(creds); | |
802 | ||
803 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
804 | packet_put_string((char *) buffer, strlen(buffer)); | |
805 | packet_send(); | |
806 | packet_write_wait(); | |
807 | ||
808 | type = packet_read(&plen); | |
809 | ||
810 | if (type == SSH_SMSG_FAILURE) | |
811 | debug("Kerberos TGT for realm %s rejected.", prealm); | |
812 | else if (type != SSH_SMSG_SUCCESS) | |
813 | packet_disconnect("Protocol error on Kerberos TGT response: %d", type); | |
814 | ||
815 | return 1; | |
8efc0c15 | 816 | } |
817 | ||
5260325f | 818 | void |
819 | send_afs_tokens(void) | |
8efc0c15 | 820 | { |
5260325f | 821 | CREDENTIALS creds; |
822 | struct ViceIoctl parms; | |
823 | struct ClearToken ct; | |
824 | int i, type, len, plen; | |
825 | char buf[2048], *p, *server_cell; | |
826 | unsigned char buffer[8192]; | |
827 | ||
828 | /* Move over ktc_GetToken, here's something leaner. */ | |
829 | for (i = 0; i < 100; i++) { /* just in case */ | |
830 | parms.in = (char *) &i; | |
831 | parms.in_size = sizeof(i); | |
832 | parms.out = buf; | |
833 | parms.out_size = sizeof(buf); | |
834 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
835 | break; | |
836 | p = buf; | |
837 | ||
838 | /* Get secret token. */ | |
839 | memcpy(&creds.ticket_st.length, p, sizeof(unsigned int)); | |
840 | if (creds.ticket_st.length > MAX_KTXT_LEN) | |
841 | break; | |
842 | p += sizeof(unsigned int); | |
843 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); | |
844 | p += creds.ticket_st.length; | |
845 | ||
846 | /* Get clear token. */ | |
847 | memcpy(&len, p, sizeof(len)); | |
848 | if (len != sizeof(struct ClearToken)) | |
849 | break; | |
850 | p += sizeof(len); | |
851 | memcpy(&ct, p, len); | |
852 | p += len; | |
853 | p += sizeof(len); /* primary flag */ | |
854 | server_cell = p; | |
855 | ||
856 | /* Flesh out our credentials. */ | |
857 | strlcpy(creds.service, "afs", sizeof creds.service); | |
858 | creds.instance[0] = '\0'; | |
859 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
860 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
861 | creds.issue_date = ct.BeginTimestamp; | |
862 | creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp); | |
863 | creds.kvno = ct.AuthHandle; | |
864 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
865 | creds.pinst[0] = '\0'; | |
866 | ||
867 | /* Encode token, ship it off. */ | |
868 | if (!creds_to_radix(&creds, buffer)) | |
869 | break; | |
870 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
871 | packet_put_string((char *) buffer, strlen(buffer)); | |
872 | packet_send(); | |
873 | packet_write_wait(); | |
874 | ||
875 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
876 | Victor? */ | |
877 | type = packet_read(&plen); | |
878 | ||
879 | if (type == SSH_SMSG_FAILURE) | |
880 | debug("AFS token for cell %s rejected.", server_cell); | |
881 | else if (type != SSH_SMSG_SUCCESS) | |
882 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
883 | } | |
8efc0c15 | 884 | } |
8efc0c15 | 885 | |
5260325f | 886 | #endif /* AFS */ |
8efc0c15 | 887 | |
57112b5a | 888 | /* |
889 | * Tries to authenticate with any string-based challenge/response system. | |
890 | * Note that the client code is not tied to s/key or TIS. | |
891 | */ | |
892 | int | |
893 | try_skey_authentication() | |
894 | { | |
895 | int type, i, payload_len; | |
896 | char *challenge, *response; | |
897 | ||
898 | debug("Doing skey authentication."); | |
899 | ||
900 | /* request a challenge */ | |
901 | packet_start(SSH_CMSG_AUTH_TIS); | |
902 | packet_send(); | |
903 | packet_write_wait(); | |
904 | ||
905 | type = packet_read(&payload_len); | |
906 | if (type != SSH_SMSG_FAILURE && | |
907 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
908 | packet_disconnect("Protocol error: got %d in response " | |
909 | "to skey-auth", type); | |
910 | } | |
911 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
912 | debug("No challenge for skey authentication."); | |
913 | return 0; | |
914 | } | |
915 | challenge = packet_get_string(&payload_len); | |
916 | if (options.cipher == SSH_CIPHER_NONE) | |
917 | log("WARNING: Encryption is disabled! " | |
918 | "Reponse will be transmitted in clear text."); | |
919 | fprintf(stderr, "%s\n", challenge); | |
920 | fflush(stderr); | |
921 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
922 | if (i != 0) | |
923 | error("Permission denied, please try again."); | |
924 | response = read_passphrase("Response: ", 0); | |
925 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); | |
926 | packet_put_string(response, strlen(response)); | |
927 | memset(response, 0, strlen(response)); | |
928 | xfree(response); | |
929 | packet_send(); | |
930 | packet_write_wait(); | |
931 | type = packet_read(&payload_len); | |
932 | if (type == SSH_SMSG_SUCCESS) | |
933 | return 1; | |
934 | if (type != SSH_SMSG_FAILURE) | |
935 | packet_disconnect("Protocol error: got %d in response " | |
936 | "to skey-auth-reponse", type); | |
937 | } | |
938 | /* failure */ | |
939 | return 0; | |
940 | } | |
941 | ||
942 | /* | |
943 | * Tries to authenticate with plain passwd authentication. | |
944 | */ | |
945 | int | |
946 | try_password_authentication(char *prompt) | |
947 | { | |
948 | int type, i, payload_len; | |
949 | char *password; | |
950 | ||
951 | debug("Doing password authentication."); | |
952 | if (options.cipher == SSH_CIPHER_NONE) | |
953 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
954 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
955 | if (i != 0) | |
956 | error("Permission denied, please try again."); | |
957 | password = read_passphrase(prompt, 0); | |
958 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
959 | packet_put_string(password, strlen(password)); | |
960 | memset(password, 0, strlen(password)); | |
961 | xfree(password); | |
962 | packet_send(); | |
963 | packet_write_wait(); | |
964 | ||
965 | type = packet_read(&payload_len); | |
966 | if (type == SSH_SMSG_SUCCESS) | |
967 | return 1; | |
968 | if (type != SSH_SMSG_FAILURE) | |
969 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
970 | } | |
971 | /* failure */ | |
972 | return 0; | |
973 | } | |
974 | ||
5260325f | 975 | /* |
976 | * Waits for the server identification string, and sends our own | |
977 | * identification string. | |
978 | */ | |
979 | void | |
980 | ssh_exchange_identification() | |
8efc0c15 | 981 | { |
5260325f | 982 | char buf[256], remote_version[256]; /* must be same size! */ |
983 | int remote_major, remote_minor, i; | |
984 | int connection_in = packet_get_connection_in(); | |
985 | int connection_out = packet_get_connection_out(); | |
5260325f | 986 | |
987 | /* Read other side\'s version identification. */ | |
988 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
989 | if (read(connection_in, &buf[i], 1) != 1) | |
990 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); | |
991 | if (buf[i] == '\r') { | |
992 | buf[i] = '\n'; | |
993 | buf[i + 1] = 0; | |
994 | break; | |
995 | } | |
996 | if (buf[i] == '\n') { | |
997 | buf[i + 1] = 0; | |
998 | break; | |
999 | } | |
8efc0c15 | 1000 | } |
5260325f | 1001 | buf[sizeof(buf) - 1] = 0; |
1002 | ||
aa3378df | 1003 | /* |
1004 | * Check that the versions match. In future this might accept | |
1005 | * several versions and set appropriate flags to handle them. | |
1006 | */ | |
5260325f | 1007 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
1008 | remote_version) != 3) | |
1009 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
1010 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
1011 | remote_major, remote_minor, remote_version); | |
1012 | ||
1013 | /* Check if the remote protocol version is too old. */ | |
1014 | if (remote_major == 1 && remote_minor < 3) | |
1015 | fatal("Remote machine has too old SSH software version."); | |
1016 | ||
1017 | /* We speak 1.3, too. */ | |
1018 | if (remote_major == 1 && remote_minor == 3) { | |
1019 | enable_compat13(); | |
1020 | if (options.forward_agent && strcmp(remote_version, SSH_VERSION) != 0) { | |
1021 | log("Agent forwarding disabled, remote version '%s' is not compatible.", | |
1022 | remote_version); | |
1023 | options.forward_agent = 0; | |
1024 | } | |
8efc0c15 | 1025 | } |
8efc0c15 | 1026 | #if 0 |
aa3378df | 1027 | /* |
1028 | * Removed for now, to permit compatibility with latter versions. The | |
1029 | * server will reject our version and disconnect if it doesn't | |
1030 | * support it. | |
1031 | */ | |
5260325f | 1032 | if (remote_major != PROTOCOL_MAJOR) |
1033 | fatal("Protocol major versions differ: %d vs. %d", | |
1034 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 1035 | #endif |
1036 | ||
5260325f | 1037 | /* Send our own protocol version identification. */ |
1038 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
a408af76 | 1039 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); |
1040 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) | |
5260325f | 1041 | fatal("write: %.100s", strerror(errno)); |
8efc0c15 | 1042 | } |
1043 | ||
1044 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
1045 | ||
5260325f | 1046 | int |
1047 | read_yes_or_no(const char *prompt, int defval) | |
8efc0c15 | 1048 | { |
5260325f | 1049 | char buf[1024]; |
1050 | FILE *f; | |
1051 | int retval = -1; | |
1052 | ||
1053 | if (isatty(0)) | |
1054 | f = stdin; | |
1055 | else | |
1056 | f = fopen("/dev/tty", "rw"); | |
1057 | ||
1058 | if (f == NULL) | |
1059 | return 0; | |
1060 | ||
1061 | fflush(stdout); | |
1062 | ||
1063 | while (1) { | |
1064 | fprintf(stderr, "%s", prompt); | |
1065 | if (fgets(buf, sizeof(buf), f) == NULL) { | |
1066 | /* Print a newline (the prompt probably didn\'t have one). */ | |
1067 | fprintf(stderr, "\n"); | |
1068 | strlcpy(buf, "no", sizeof buf); | |
1069 | } | |
1070 | /* Remove newline from response. */ | |
1071 | if (strchr(buf, '\n')) | |
1072 | *strchr(buf, '\n') = 0; | |
1073 | ||
1074 | if (buf[0] == 0) | |
1075 | retval = defval; | |
1076 | if (strcmp(buf, "yes") == 0) | |
1077 | retval = 1; | |
1078 | if (strcmp(buf, "no") == 0) | |
1079 | retval = 0; | |
1080 | ||
1081 | if (retval != -1) { | |
1082 | if (f != stdin) | |
1083 | fclose(f); | |
1084 | return retval; | |
1085 | } | |
8efc0c15 | 1086 | } |
8efc0c15 | 1087 | } |
1088 | ||
5260325f | 1089 | /* |
1090 | * Starts a dialog with the server, and authenticates the current user on the | |
1091 | * server. This does not need any extra privileges. The basic connection | |
1092 | * to the server must already have been established before this is called. | |
1093 | * User is the remote user; if it is NULL, the current local user name will | |
1094 | * be used. Anonymous indicates that no rhosts authentication will be used. | |
1095 | * If login fails, this function prints an error and never returns. | |
1096 | * This function does not require super-user privileges. | |
1097 | */ | |
1098 | void | |
1099 | ssh_login(int host_key_valid, | |
1100 | RSA *own_host_key, | |
1101 | const char *orighost, | |
1102 | struct sockaddr_in *hostaddr, | |
1103 | uid_t original_real_uid) | |
8efc0c15 | 1104 | { |
5260325f | 1105 | int i, type; |
5260325f | 1106 | struct passwd *pw; |
1107 | BIGNUM *key; | |
1108 | RSA *host_key, *file_key; | |
1109 | RSA *public_key; | |
1110 | int bits, rbits; | |
1111 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
1112 | const char *server_user, *local_user; | |
1113 | char *cp, *host, *ip = NULL; | |
1114 | char hostline[1000], *hostp; | |
1115 | unsigned char check_bytes[8]; | |
1116 | unsigned int supported_ciphers, supported_authentications, protocol_flags; | |
1117 | HostStatus host_status; | |
1118 | HostStatus ip_status; | |
1119 | int host_ip_differ = 0; | |
1120 | int local = (ntohl(hostaddr->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; | |
1121 | int payload_len, clen, sum_len = 0; | |
1122 | u_int32_t rand = 0; | |
1123 | ||
57112b5a | 1124 | /* |
1125 | * Turn off check_host_ip for proxy connects, since | |
1126 | * we don't have the remote ip-address | |
1127 | */ | |
1128 | if (options.proxy_command != NULL && options.check_host_ip) | |
1129 | options.check_host_ip = 0; | |
1130 | ||
5260325f | 1131 | if (options.check_host_ip) |
1132 | ip = xstrdup(inet_ntoa(hostaddr->sin_addr)); | |
1133 | ||
1134 | /* Convert the user-supplied hostname into all lowercase. */ | |
1135 | host = xstrdup(orighost); | |
1136 | for (cp = host; *cp; cp++) | |
1137 | if (isupper(*cp)) | |
1138 | *cp = tolower(*cp); | |
1139 | ||
1140 | /* Exchange protocol version identification strings with the server. */ | |
1141 | ssh_exchange_identification(); | |
1142 | ||
1143 | /* Put the connection into non-blocking mode. */ | |
1144 | packet_set_nonblocking(); | |
1145 | ||
1146 | /* Get local user name. Use it as server user if no user name was given. */ | |
1147 | pw = getpwuid(original_real_uid); | |
1148 | if (!pw) | |
1149 | fatal("User id %d not found from user database.", original_real_uid); | |
1150 | local_user = xstrdup(pw->pw_name); | |
1151 | server_user = options.user ? options.user : local_user; | |
1152 | ||
1153 | debug("Waiting for server public key."); | |
1154 | ||
1155 | /* Wait for a public key packet from the server. */ | |
1156 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
1157 | ||
1158 | /* Get check bytes from the packet. */ | |
1159 | for (i = 0; i < 8; i++) | |
1160 | check_bytes[i] = packet_get_char(); | |
1161 | ||
1162 | /* Get the public key. */ | |
1163 | public_key = RSA_new(); | |
1164 | bits = packet_get_int();/* bits */ | |
1165 | public_key->e = BN_new(); | |
1166 | packet_get_bignum(public_key->e, &clen); | |
1167 | sum_len += clen; | |
1168 | public_key->n = BN_new(); | |
1169 | packet_get_bignum(public_key->n, &clen); | |
1170 | sum_len += clen; | |
1171 | ||
1172 | rbits = BN_num_bits(public_key->n); | |
1173 | if (bits != rbits) { | |
1174 | log("Warning: Server lies about size of server public key: " | |
1175 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1176 | log("Warning: This may be due to an old implementation of ssh."); | |
1177 | } | |
1178 | /* Get the host key. */ | |
1179 | host_key = RSA_new(); | |
1180 | bits = packet_get_int();/* bits */ | |
1181 | host_key->e = BN_new(); | |
1182 | packet_get_bignum(host_key->e, &clen); | |
1183 | sum_len += clen; | |
1184 | host_key->n = BN_new(); | |
1185 | packet_get_bignum(host_key->n, &clen); | |
1186 | sum_len += clen; | |
1187 | ||
1188 | rbits = BN_num_bits(host_key->n); | |
1189 | if (bits != rbits) { | |
1190 | log("Warning: Server lies about size of server host key: " | |
1191 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1192 | log("Warning: This may be due to an old implementation of ssh."); | |
1193 | } | |
1194 | /* Store the host key from the known host file in here so that we | |
1195 | can compare it with the key for the IP address. */ | |
1196 | file_key = RSA_new(); | |
1197 | file_key->n = BN_new(); | |
1198 | file_key->e = BN_new(); | |
1199 | ||
1200 | /* Get protocol flags. */ | |
1201 | protocol_flags = packet_get_int(); | |
1202 | packet_set_protocol_flags(protocol_flags); | |
1203 | ||
5260325f | 1204 | supported_ciphers = packet_get_int(); |
5260325f | 1205 | supported_authentications = packet_get_int(); |
1206 | ||
1207 | debug("Received server public key (%d bits) and host key (%d bits).", | |
1208 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
1209 | ||
1210 | packet_integrity_check(payload_len, | |
1211 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
1212 | SSH_SMSG_PUBLIC_KEY); | |
1213 | ||
5260325f | 1214 | compute_session_id(session_id, check_bytes, host_key->n, public_key->n); |
1215 | ||
aa3378df | 1216 | /* |
1217 | * Check if the host key is present in the user\'s list of known | |
1218 | * hosts or in the systemwide list. | |
1219 | */ | |
5260325f | 1220 | host_status = check_host_in_hostfile(options.user_hostfile, host, |
1221 | host_key->e, host_key->n, | |
1222 | file_key->e, file_key->n); | |
1223 | if (host_status == HOST_NEW) | |
1224 | host_status = check_host_in_hostfile(options.system_hostfile, host, | |
1225 | host_key->e, host_key->n, | |
1226 | file_key->e, file_key->n); | |
aa3378df | 1227 | /* |
1228 | * Force accepting of the host key for localhost and 127.0.0.1. The | |
1229 | * problem is that if the home directory is NFS-mounted to multiple | |
1230 | * machines, localhost will refer to a different machine in each of | |
1231 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
1232 | * essentially disables host authentication for localhost; however, | |
1233 | * this is probably not a real problem. | |
1234 | */ | |
5260325f | 1235 | if (local) { |
1236 | debug("Forcing accepting of host key for localhost."); | |
1237 | host_status = HOST_OK; | |
1238 | } | |
aa3378df | 1239 | /* |
1240 | * Also perform check for the ip address, skip the check if we are | |
1241 | * localhost or the hostname was an ip address to begin with | |
1242 | */ | |
5260325f | 1243 | if (options.check_host_ip && !local && strcmp(host, ip)) { |
1244 | RSA *ip_key = RSA_new(); | |
1245 | ip_key->n = BN_new(); | |
1246 | ip_key->e = BN_new(); | |
1247 | ip_status = check_host_in_hostfile(options.user_hostfile, ip, | |
1248 | host_key->e, host_key->n, | |
1249 | ip_key->e, ip_key->n); | |
1250 | ||
1251 | if (ip_status == HOST_NEW) | |
1252 | ip_status = check_host_in_hostfile(options.system_hostfile, ip, | |
1253 | host_key->e, host_key->n, | |
1254 | ip_key->e, ip_key->n); | |
1255 | if (host_status == HOST_CHANGED && | |
1256 | (ip_status != HOST_CHANGED || | |
1257 | (BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n)))) | |
1258 | host_ip_differ = 1; | |
1259 | ||
1260 | RSA_free(ip_key); | |
1261 | } else | |
1262 | ip_status = host_status; | |
1263 | ||
1264 | RSA_free(file_key); | |
1265 | ||
1266 | switch (host_status) { | |
1267 | case HOST_OK: | |
1268 | /* The host is known and the key matches. */ | |
1269 | debug("Host '%.200s' is known and matches the host key.", host); | |
1270 | if (options.check_host_ip) { | |
1271 | if (ip_status == HOST_NEW) { | |
1272 | if (!add_host_to_hostfile(options.user_hostfile, ip, | |
1273 | host_key->e, host_key->n)) | |
1274 | log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).", | |
1275 | ip, options.user_hostfile); | |
1276 | else | |
1277 | log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.", | |
1278 | ip); | |
1279 | } else if (ip_status != HOST_OK) | |
1280 | log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'", | |
1281 | host, ip); | |
1282 | } | |
1283 | break; | |
1284 | case HOST_NEW: | |
1285 | /* The host is new. */ | |
1286 | if (options.strict_host_key_checking == 1) { | |
1287 | /* User has requested strict host key checking. We will not add the host key | |
1288 | automatically. The only alternative left is to abort. */ | |
1289 | fatal("No host key is known for %.200s and you have requested strict checking.", host); | |
1290 | } else if (options.strict_host_key_checking == 2) { | |
1291 | /* The default */ | |
1292 | char prompt[1024]; | |
1293 | char *fp = fingerprint(host_key->e, host_key->n); | |
1294 | snprintf(prompt, sizeof(prompt), | |
a408af76 | 1295 | "The authenticity of host '%.200s' can't be established.\n" |
1296 | "Key fingerprint is %d %s.\n" | |
1297 | "Are you sure you want to continue connecting (yes/no)? ", | |
1298 | host, BN_num_bits(host_key->n), fp); | |
5260325f | 1299 | if (!read_yes_or_no(prompt, -1)) |
1300 | fatal("Aborted by user!\n"); | |
1301 | } | |
1302 | if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) { | |
1303 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); | |
1304 | hostp = hostline; | |
1305 | } else | |
1306 | hostp = host; | |
1307 | ||
1308 | /* If not in strict mode, add the key automatically to the local known_hosts file. */ | |
1309 | if (!add_host_to_hostfile(options.user_hostfile, hostp, | |
1310 | host_key->e, host_key->n)) | |
1311 | log("Failed to add the host to the list of known hosts (%.500s).", | |
1312 | options.user_hostfile); | |
1313 | else | |
1314 | log("Warning: Permanently added '%.200s' to the list of known hosts.", | |
1315 | hostp); | |
1316 | break; | |
1317 | case HOST_CHANGED: | |
1318 | if (options.check_host_ip && host_ip_differ) { | |
1319 | char *msg; | |
1320 | if (ip_status == HOST_NEW) | |
1321 | msg = "is unknown"; | |
1322 | else if (ip_status == HOST_OK) | |
1323 | msg = "is unchanged"; | |
1324 | else | |
1325 | msg = "has a different value"; | |
1326 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1327 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
1328 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1329 | error("The host key for %s has changed,", host); | |
1330 | error("and the key for the according IP address %s", ip); | |
1331 | error("%s. This could either mean that", msg); | |
1332 | error("DNS SPOOFING is happening or the IP address for the host"); | |
1333 | error("and its host key have changed at the same time"); | |
1334 | } | |
1335 | /* The host key has changed. */ | |
1336 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1337 | error("@ WARNING: HOST IDENTIFICATION HAS CHANGED! @"); | |
1338 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1339 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1340 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1341 | error("It is also possible that the host key has just been changed."); | |
1342 | error("Please contact your system administrator."); | |
1343 | error("Add correct host key in %.100s to get rid of this message.", | |
1344 | options.user_hostfile); | |
1345 | ||
aa3378df | 1346 | /* |
1347 | * If strict host key checking is in use, the user will have | |
1348 | * to edit the key manually and we can only abort. | |
1349 | */ | |
5260325f | 1350 | if (options.strict_host_key_checking) |
1351 | fatal("Host key for %.200s has changed and you have requested strict checking.", host); | |
1352 | ||
aa3378df | 1353 | /* |
1354 | * If strict host key checking has not been requested, allow | |
1355 | * the connection but without password authentication or | |
1356 | * agent forwarding. | |
1357 | */ | |
5260325f | 1358 | if (options.password_authentication) { |
1359 | error("Password authentication is disabled to avoid trojan horses."); | |
1360 | options.password_authentication = 0; | |
1361 | } | |
1362 | if (options.forward_agent) { | |
1363 | error("Agent forwarding is disabled to avoid trojan horses."); | |
1364 | options.forward_agent = 0; | |
1365 | } | |
aa3378df | 1366 | /* |
1367 | * XXX Should permit the user to change to use the new id. | |
1368 | * This could be done by converting the host key to an | |
1369 | * identifying sentence, tell that the host identifies itself | |
1370 | * by that sentence, and ask the user if he/she whishes to | |
1371 | * accept the authentication. | |
1372 | */ | |
5260325f | 1373 | break; |
1374 | } | |
1375 | ||
1376 | if (options.check_host_ip) | |
1377 | xfree(ip); | |
1378 | ||
1379 | /* Generate a session key. */ | |
1380 | arc4random_stir(); | |
1381 | ||
aa3378df | 1382 | /* |
1383 | * Generate an encryption key for the session. The key is a 256 bit | |
1384 | * random number, interpreted as a 32-byte key, with the least | |
1385 | * significant 8 bits being the first byte of the key. | |
1386 | */ | |
5260325f | 1387 | for (i = 0; i < 32; i++) { |
1388 | if (i % 4 == 0) | |
1389 | rand = arc4random(); | |
1390 | session_key[i] = rand & 0xff; | |
1391 | rand >>= 8; | |
1392 | } | |
1393 | ||
aa3378df | 1394 | /* |
1395 | * According to the protocol spec, the first byte of the session key | |
1396 | * is the highest byte of the integer. The session key is xored with | |
1397 | * the first 16 bytes of the session id. | |
1398 | */ | |
5260325f | 1399 | key = BN_new(); |
1400 | BN_set_word(key, 0); | |
1401 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1402 | BN_lshift(key, key, 8); | |
1403 | if (i < 16) | |
1404 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1405 | else | |
1406 | BN_add_word(key, session_key[i]); | |
1407 | } | |
1408 | ||
aa3378df | 1409 | /* |
1410 | * Encrypt the integer using the public key and host key of the | |
1411 | * server (key with smaller modulus first). | |
1412 | */ | |
5260325f | 1413 | if (BN_cmp(public_key->n, host_key->n) < 0) { |
1414 | /* Public key has smaller modulus. */ | |
1415 | if (BN_num_bits(host_key->n) < | |
1416 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1417 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1418 | "SSH_KEY_BITS_RESERVED %d", | |
1419 | BN_num_bits(host_key->n), | |
1420 | BN_num_bits(public_key->n), | |
1421 | SSH_KEY_BITS_RESERVED); | |
1422 | } | |
1423 | rsa_public_encrypt(key, key, public_key); | |
1424 | rsa_public_encrypt(key, key, host_key); | |
1425 | } else { | |
1426 | /* Host key has smaller modulus (or they are equal). */ | |
1427 | if (BN_num_bits(public_key->n) < | |
1428 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1429 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1430 | "SSH_KEY_BITS_RESERVED %d", | |
1431 | BN_num_bits(public_key->n), | |
1432 | BN_num_bits(host_key->n), | |
1433 | SSH_KEY_BITS_RESERVED); | |
1434 | } | |
1435 | rsa_public_encrypt(key, key, host_key); | |
1436 | rsa_public_encrypt(key, key, public_key); | |
1437 | } | |
1438 | ||
1439 | if (options.cipher == SSH_CIPHER_NOT_SET) { | |
1440 | if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default)) | |
1441 | options.cipher = ssh_cipher_default; | |
1442 | else { | |
1443 | debug("Cipher %s not supported, using %.100s instead.", | |
1444 | cipher_name(ssh_cipher_default), | |
1445 | cipher_name(SSH_FALLBACK_CIPHER)); | |
1446 | options.cipher = SSH_FALLBACK_CIPHER; | |
1447 | } | |
1448 | } | |
1449 | /* Check that the selected cipher is supported. */ | |
1450 | if (!(supported_ciphers & (1 << options.cipher))) | |
1451 | fatal("Selected cipher type %.100s not supported by server.", | |
1452 | cipher_name(options.cipher)); | |
1453 | ||
1454 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1455 | ||
1456 | /* Send the encrypted session key to the server. */ | |
1457 | packet_start(SSH_CMSG_SESSION_KEY); | |
1458 | packet_put_char(options.cipher); | |
1459 | ||
1460 | /* Send the check bytes back to the server. */ | |
1461 | for (i = 0; i < 8; i++) | |
1462 | packet_put_char(check_bytes[i]); | |
1463 | ||
1464 | /* Send the encrypted encryption key. */ | |
1465 | packet_put_bignum(key); | |
1466 | ||
1467 | /* Send protocol flags. */ | |
1468 | packet_put_int(SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN); | |
1469 | ||
1470 | /* Send the packet now. */ | |
8efc0c15 | 1471 | packet_send(); |
1472 | packet_write_wait(); | |
5260325f | 1473 | |
1474 | /* Destroy the session key integer and the public keys since we no longer need them. */ | |
1475 | BN_clear_free(key); | |
1476 | RSA_free(public_key); | |
1477 | RSA_free(host_key); | |
1478 | ||
1479 | debug("Sent encrypted session key."); | |
1480 | ||
1481 | /* Set the encryption key. */ | |
1482 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1483 | ||
1484 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1485 | memset(session_key, 0, sizeof(session_key)); | |
1486 | ||
aa3378df | 1487 | /* |
1488 | * Expect a success message from the server. Note that this message | |
1489 | * will be received in encrypted form. | |
1490 | */ | |
5260325f | 1491 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); |
1492 | ||
1493 | debug("Received encrypted confirmation."); | |
1494 | ||
1495 | /* Send the name of the user to log in as on the server. */ | |
1496 | packet_start(SSH_CMSG_USER); | |
1497 | packet_put_string(server_user, strlen(server_user)); | |
1498 | packet_send(); | |
1499 | packet_write_wait(); | |
1500 | ||
aa3378df | 1501 | /* |
1502 | * The server should respond with success if no authentication is | |
1503 | * needed (the user has no password). Otherwise the server responds | |
1504 | * with failure. | |
1505 | */ | |
8efc0c15 | 1506 | type = packet_read(&payload_len); |
5260325f | 1507 | |
1508 | /* check whether the connection was accepted without authentication. */ | |
8efc0c15 | 1509 | if (type == SSH_SMSG_SUCCESS) |
5260325f | 1510 | return; |
8efc0c15 | 1511 | if (type != SSH_SMSG_FAILURE) |
5260325f | 1512 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", |
1513 | type); | |
1514 | ||
1515 | #ifdef AFS | |
1516 | /* Try Kerberos tgt passing if the server supports it. */ | |
1517 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1518 | options.kerberos_tgt_passing) { | |
1519 | if (options.cipher == SSH_CIPHER_NONE) | |
1520 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1521 | (void) send_kerberos_tgt(); | |
1522 | } | |
1523 | /* Try AFS token passing if the server supports it. */ | |
1524 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1525 | options.afs_token_passing && k_hasafs()) { | |
1526 | if (options.cipher == SSH_CIPHER_NONE) | |
1527 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1528 | send_afs_tokens(); | |
1529 | } | |
1530 | #endif /* AFS */ | |
8efc0c15 | 1531 | |
5260325f | 1532 | #ifdef KRB4 |
1533 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1534 | options.kerberos_authentication) { | |
1535 | debug("Trying Kerberos authentication."); | |
1536 | if (try_kerberos_authentication()) { | |
1537 | /* The server should respond with success or failure. */ | |
1538 | type = packet_read(&payload_len); | |
1539 | if (type == SSH_SMSG_SUCCESS) | |
1540 | return; | |
1541 | if (type != SSH_SMSG_FAILURE) | |
1542 | packet_disconnect("Protocol error: got %d in response to Kerberos auth", type); | |
1543 | } | |
1544 | } | |
1545 | #endif /* KRB4 */ | |
1546 | ||
aa3378df | 1547 | /* |
1548 | * Use rhosts authentication if running in privileged socket and we | |
1549 | * do not wish to remain anonymous. | |
1550 | */ | |
5260325f | 1551 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && |
1552 | options.rhosts_authentication) { | |
1553 | debug("Trying rhosts authentication."); | |
1554 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
1555 | packet_put_string(local_user, strlen(local_user)); | |
1556 | packet_send(); | |
1557 | packet_write_wait(); | |
1558 | ||
1559 | /* The server should respond with success or failure. */ | |
1560 | type = packet_read(&payload_len); | |
1561 | if (type == SSH_SMSG_SUCCESS) | |
1562 | return; | |
1563 | if (type != SSH_SMSG_FAILURE) | |
1564 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1565 | type); | |
1566 | } | |
aa3378df | 1567 | /* |
1568 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1569 | * authentication. | |
1570 | */ | |
5260325f | 1571 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && |
1572 | options.rhosts_rsa_authentication && host_key_valid) { | |
1573 | if (try_rhosts_rsa_authentication(local_user, own_host_key)) | |
1574 | return; | |
1575 | } | |
1576 | /* Try RSA authentication if the server supports it. */ | |
1577 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1578 | options.rsa_authentication) { | |
aa3378df | 1579 | /* |
1580 | * Try RSA authentication using the authentication agent. The | |
1581 | * agent is tried first because no passphrase is needed for | |
1582 | * it, whereas identity files may require passphrases. | |
1583 | */ | |
5260325f | 1584 | if (try_agent_authentication()) |
1585 | return; | |
1586 | ||
1587 | /* Try RSA authentication for each identity. */ | |
1588 | for (i = 0; i < options.num_identity_files; i++) | |
57112b5a | 1589 | if (try_rsa_authentication(options.identity_files[i])) |
5260325f | 1590 | return; |
1591 | } | |
1592 | /* Try skey authentication if the server supports it. */ | |
1593 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && | |
1594 | options.skey_authentication && !options.batch_mode) { | |
57112b5a | 1595 | if (try_skey_authentication()) |
1596 | return; | |
5260325f | 1597 | } |
1598 | /* Try password authentication if the server supports it. */ | |
1599 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1600 | options.password_authentication && !options.batch_mode) { | |
1601 | char prompt[80]; | |
a408af76 | 1602 | |
57112b5a | 1603 | snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
a408af76 | 1604 | server_user, host); |
57112b5a | 1605 | if (try_password_authentication(prompt)) |
1606 | return; | |
5260325f | 1607 | } |
1608 | /* All authentication methods have failed. Exit with an error message. */ | |
1609 | fatal("Permission denied."); | |
1610 | /* NOTREACHED */ | |
8efc0c15 | 1611 | } |