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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 { | |
95f1eccc | 159 | /* |
160 | * Just create an ordinary socket on arbitrary port. We use | |
161 | * the user's uid to create the socket. | |
162 | */ | |
5260325f | 163 | temporarily_use_uid(original_real_uid); |
164 | sock = socket(AF_INET, SOCK_STREAM, 0); | |
165 | if (sock < 0) | |
166 | fatal("socket: %.100s", strerror(errno)); | |
167 | restore_uid(); | |
168 | } | |
169 | return sock; | |
8efc0c15 | 170 | } |
171 | ||
5260325f | 172 | /* |
173 | * Opens a TCP/IP connection to the remote server on the given host. If | |
174 | * port is 0, the default port will be used. If anonymous is zero, | |
175 | * a privileged port will be allocated to make the connection. | |
176 | * This requires super-user privileges if anonymous is false. | |
177 | * Connection_attempts specifies the maximum number of tries (one per | |
178 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
179 | * and %p substituted for host and port, respectively) to use to contact | |
180 | * the daemon. | |
181 | */ | |
182 | int | |
183 | ssh_connect(const char *host, struct sockaddr_in * hostaddr, | |
57112b5a | 184 | u_short port, int connection_attempts, |
5260325f | 185 | int anonymous, uid_t original_real_uid, |
186 | const char *proxy_command) | |
8efc0c15 | 187 | { |
5260325f | 188 | int sock = -1, attempt, i; |
189 | int on = 1; | |
190 | struct servent *sp; | |
191 | struct hostent *hp; | |
192 | struct linger linger; | |
193 | ||
194 | debug("ssh_connect: getuid %d geteuid %d anon %d", | |
195 | (int) getuid(), (int) geteuid(), anonymous); | |
196 | ||
197 | /* Get default port if port has not been set. */ | |
198 | if (port == 0) { | |
199 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); | |
200 | if (sp) | |
201 | port = ntohs(sp->s_port); | |
202 | else | |
203 | port = SSH_DEFAULT_PORT; | |
8efc0c15 | 204 | } |
5260325f | 205 | /* If a proxy command is given, connect using it. */ |
206 | if (proxy_command != NULL) | |
207 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); | |
208 | ||
209 | /* No proxy command. */ | |
210 | ||
211 | /* No host lookup made yet. */ | |
212 | hp = NULL; | |
213 | ||
95f1eccc | 214 | /* |
215 | * Try to connect several times. On some machines, the first time | |
216 | * will sometimes fail. In general socket code appears to behave | |
217 | * quite magically on many machines. | |
218 | */ | |
5260325f | 219 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
220 | if (attempt > 0) | |
221 | debug("Trying again..."); | |
222 | ||
223 | /* Try to parse the host name as a numeric inet address. */ | |
224 | memset(hostaddr, 0, sizeof(hostaddr)); | |
225 | hostaddr->sin_family = AF_INET; | |
226 | hostaddr->sin_port = htons(port); | |
227 | hostaddr->sin_addr.s_addr = inet_addr(host); | |
228 | if ((hostaddr->sin_addr.s_addr & 0xffffffff) != 0xffffffff) { | |
229 | /* Valid numeric IP address */ | |
230 | debug("Connecting to %.100s port %d.", | |
231 | inet_ntoa(hostaddr->sin_addr), port); | |
232 | ||
233 | /* Create a socket. */ | |
234 | sock = ssh_create_socket(original_real_uid, | |
235 | !anonymous && geteuid() == 0 && | |
236 | port < IPPORT_RESERVED); | |
237 | ||
aa3378df | 238 | /* |
239 | * Connect to the host. We use the user's uid in the | |
240 | * hope that it will help with the problems of | |
241 | * tcp_wrappers showing the remote uid as root. | |
242 | */ | |
5260325f | 243 | temporarily_use_uid(original_real_uid); |
244 | if (connect(sock, (struct sockaddr *) hostaddr, sizeof(*hostaddr)) | |
245 | >= 0) { | |
246 | /* Successful connect. */ | |
247 | restore_uid(); | |
248 | break; | |
249 | } | |
250 | debug("connect: %.100s", strerror(errno)); | |
251 | restore_uid(); | |
252 | ||
253 | /* Destroy the failed socket. */ | |
254 | shutdown(sock, SHUT_RDWR); | |
255 | close(sock); | |
256 | } else { | |
257 | /* Not a valid numeric inet address. */ | |
258 | /* Map host name to an address. */ | |
259 | if (!hp) | |
260 | hp = gethostbyname(host); | |
261 | if (!hp) | |
262 | fatal("Bad host name: %.100s", host); | |
263 | if (!hp->h_addr_list[0]) | |
264 | fatal("Host does not have an IP address: %.100s", host); | |
265 | ||
266 | /* Loop through addresses for this host, and try | |
267 | each one in sequence until the connection | |
268 | succeeds. */ | |
269 | for (i = 0; hp->h_addr_list[i]; i++) { | |
270 | /* Set the address to connect to. */ | |
271 | hostaddr->sin_family = hp->h_addrtype; | |
272 | memcpy(&hostaddr->sin_addr, hp->h_addr_list[i], | |
273 | sizeof(hostaddr->sin_addr)); | |
274 | ||
275 | debug("Connecting to %.200s [%.100s] port %d.", | |
276 | host, inet_ntoa(hostaddr->sin_addr), port); | |
277 | ||
278 | /* Create a socket for connecting. */ | |
279 | sock = ssh_create_socket(original_real_uid, | |
280 | !anonymous && geteuid() == 0 && | |
281 | port < IPPORT_RESERVED); | |
282 | ||
aa3378df | 283 | /* |
284 | * Connect to the host. We use the user's | |
285 | * uid in the hope that it will help with | |
286 | * tcp_wrappers showing the remote uid as | |
287 | * root. | |
288 | */ | |
5260325f | 289 | temporarily_use_uid(original_real_uid); |
290 | if (connect(sock, (struct sockaddr *) hostaddr, | |
291 | sizeof(*hostaddr)) >= 0) { | |
292 | /* Successful connection. */ | |
293 | restore_uid(); | |
294 | break; | |
295 | } | |
296 | debug("connect: %.100s", strerror(errno)); | |
297 | restore_uid(); | |
298 | ||
aa3378df | 299 | /* |
300 | * Close the failed socket; there appear to | |
301 | * be some problems when reusing a socket for | |
302 | * which connect() has already returned an | |
303 | * error. | |
304 | */ | |
5260325f | 305 | shutdown(sock, SHUT_RDWR); |
306 | close(sock); | |
307 | } | |
308 | if (hp->h_addr_list[i]) | |
309 | break; /* Successful connection. */ | |
8efc0c15 | 310 | } |
8efc0c15 | 311 | |
5260325f | 312 | /* Sleep a moment before retrying. */ |
313 | sleep(1); | |
314 | } | |
315 | /* Return failure if we didn't get a successful connection. */ | |
316 | if (attempt >= connection_attempts) | |
317 | return 0; | |
8efc0c15 | 318 | |
5260325f | 319 | debug("Connection established."); |
8efc0c15 | 320 | |
aa3378df | 321 | /* |
322 | * Set socket options. We would like the socket to disappear as soon | |
323 | * as it has been closed for whatever reason. | |
324 | */ | |
325 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 326 | setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, (void *) &on, sizeof(on)); |
327 | linger.l_onoff = 1; | |
328 | linger.l_linger = 5; | |
329 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
8efc0c15 | 330 | |
5260325f | 331 | /* Set the connection. */ |
332 | packet_set_connection(sock, sock); | |
8efc0c15 | 333 | |
5260325f | 334 | return 1; |
8efc0c15 | 335 | } |
336 | ||
5260325f | 337 | /* |
338 | * Checks if the user has an authentication agent, and if so, tries to | |
339 | * authenticate using the agent. | |
340 | */ | |
8efc0c15 | 341 | int |
342 | try_agent_authentication() | |
343 | { | |
5260325f | 344 | int status, type; |
345 | char *comment; | |
346 | AuthenticationConnection *auth; | |
347 | unsigned char response[16]; | |
348 | unsigned int i; | |
349 | BIGNUM *e, *n, *challenge; | |
350 | ||
351 | /* Get connection to the agent. */ | |
352 | auth = ssh_get_authentication_connection(); | |
353 | if (!auth) | |
354 | return 0; | |
355 | ||
356 | e = BN_new(); | |
357 | n = BN_new(); | |
358 | challenge = BN_new(); | |
359 | ||
360 | /* Loop through identities served by the agent. */ | |
361 | for (status = ssh_get_first_identity(auth, e, n, &comment); | |
362 | status; | |
363 | status = ssh_get_next_identity(auth, e, n, &comment)) { | |
364 | int plen, clen; | |
365 | ||
366 | /* Try this identity. */ | |
367 | debug("Trying RSA authentication via agent with '%.100s'", comment); | |
368 | xfree(comment); | |
369 | ||
370 | /* Tell the server that we are willing to authenticate using this key. */ | |
371 | packet_start(SSH_CMSG_AUTH_RSA); | |
372 | packet_put_bignum(n); | |
373 | packet_send(); | |
374 | packet_write_wait(); | |
375 | ||
376 | /* Wait for server's response. */ | |
377 | type = packet_read(&plen); | |
378 | ||
379 | /* The server sends failure if it doesn\'t like our key or | |
380 | does not support RSA authentication. */ | |
381 | if (type == SSH_SMSG_FAILURE) { | |
382 | debug("Server refused our key."); | |
383 | continue; | |
384 | } | |
385 | /* Otherwise it should have sent a challenge. */ | |
386 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
387 | packet_disconnect("Protocol error during RSA authentication: %d", | |
388 | type); | |
8efc0c15 | 389 | |
5260325f | 390 | packet_get_bignum(challenge, &clen); |
8efc0c15 | 391 | |
5260325f | 392 | packet_integrity_check(plen, clen, type); |
8efc0c15 | 393 | |
5260325f | 394 | debug("Received RSA challenge from server."); |
395 | ||
396 | /* Ask the agent to decrypt the challenge. */ | |
397 | if (!ssh_decrypt_challenge(auth, e, n, challenge, | |
398 | session_id, 1, response)) { | |
399 | /* The agent failed to authenticate this identifier although it | |
400 | advertised it supports this. Just return a wrong value. */ | |
401 | log("Authentication agent failed to decrypt challenge."); | |
402 | memset(response, 0, sizeof(response)); | |
403 | } | |
404 | debug("Sending response to RSA challenge."); | |
405 | ||
406 | /* Send the decrypted challenge back to the server. */ | |
407 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
408 | for (i = 0; i < 16; i++) | |
409 | packet_put_char(response[i]); | |
410 | packet_send(); | |
411 | packet_write_wait(); | |
412 | ||
413 | /* Wait for response from the server. */ | |
414 | type = packet_read(&plen); | |
415 | ||
416 | /* The server returns success if it accepted the authentication. */ | |
417 | if (type == SSH_SMSG_SUCCESS) { | |
418 | debug("RSA authentication accepted by server."); | |
419 | BN_clear_free(e); | |
420 | BN_clear_free(n); | |
421 | BN_clear_free(challenge); | |
422 | return 1; | |
423 | } | |
424 | /* Otherwise it should return failure. */ | |
425 | if (type != SSH_SMSG_FAILURE) | |
426 | packet_disconnect("Protocol error waiting RSA auth response: %d", | |
427 | type); | |
428 | } | |
429 | ||
430 | BN_clear_free(e); | |
431 | BN_clear_free(n); | |
432 | BN_clear_free(challenge); | |
8efc0c15 | 433 | |
5260325f | 434 | debug("RSA authentication using agent refused."); |
435 | return 0; | |
436 | } | |
8efc0c15 | 437 | |
5260325f | 438 | /* |
439 | * Computes the proper response to a RSA challenge, and sends the response to | |
440 | * the server. | |
441 | */ | |
8efc0c15 | 442 | void |
5260325f | 443 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
8efc0c15 | 444 | { |
5260325f | 445 | unsigned char buf[32], response[16]; |
446 | MD5_CTX md; | |
447 | int i, len; | |
448 | ||
449 | /* Decrypt the challenge using the private key. */ | |
450 | rsa_private_decrypt(challenge, challenge, prv); | |
451 | ||
452 | /* Compute the response. */ | |
453 | /* The response is MD5 of decrypted challenge plus session id. */ | |
454 | len = BN_num_bytes(challenge); | |
455 | if (len <= 0 || len > sizeof(buf)) | |
456 | packet_disconnect("respond_to_rsa_challenge: bad challenge length %d", | |
457 | len); | |
458 | ||
459 | memset(buf, 0, sizeof(buf)); | |
460 | BN_bn2bin(challenge, buf + sizeof(buf) - len); | |
461 | MD5_Init(&md); | |
462 | MD5_Update(&md, buf, 32); | |
463 | MD5_Update(&md, session_id, 16); | |
464 | MD5_Final(response, &md); | |
465 | ||
466 | debug("Sending response to host key RSA challenge."); | |
467 | ||
468 | /* Send the response back to the server. */ | |
469 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
470 | for (i = 0; i < 16; i++) | |
471 | packet_put_char(response[i]); | |
472 | packet_send(); | |
473 | packet_write_wait(); | |
8efc0c15 | 474 | |
5260325f | 475 | memset(buf, 0, sizeof(buf)); |
476 | memset(response, 0, sizeof(response)); | |
477 | memset(&md, 0, sizeof(md)); | |
478 | } | |
8efc0c15 | 479 | |
5260325f | 480 | /* |
481 | * Checks if the user has authentication file, and if so, tries to authenticate | |
482 | * the user using it. | |
483 | */ | |
8efc0c15 | 484 | int |
57112b5a | 485 | try_rsa_authentication(const char *authfile) |
8efc0c15 | 486 | { |
5260325f | 487 | BIGNUM *challenge; |
488 | RSA *private_key; | |
489 | RSA *public_key; | |
490 | char *passphrase, *comment; | |
491 | int type, i; | |
492 | int plen, clen; | |
493 | ||
494 | /* Try to load identification for the authentication key. */ | |
495 | public_key = RSA_new(); | |
496 | if (!load_public_key(authfile, public_key, &comment)) { | |
497 | RSA_free(public_key); | |
57112b5a | 498 | /* Could not load it. Fail. */ |
499 | return 0; | |
8efc0c15 | 500 | } |
5260325f | 501 | debug("Trying RSA authentication with key '%.100s'", comment); |
502 | ||
503 | /* Tell the server that we are willing to authenticate using this key. */ | |
504 | packet_start(SSH_CMSG_AUTH_RSA); | |
505 | packet_put_bignum(public_key->n); | |
506 | packet_send(); | |
507 | packet_write_wait(); | |
508 | ||
509 | /* We no longer need the public key. */ | |
510 | RSA_free(public_key); | |
511 | ||
512 | /* Wait for server's response. */ | |
513 | type = packet_read(&plen); | |
514 | ||
aa3378df | 515 | /* |
516 | * The server responds with failure if it doesn\'t like our key or | |
517 | * doesn\'t support RSA authentication. | |
518 | */ | |
5260325f | 519 | if (type == SSH_SMSG_FAILURE) { |
520 | debug("Server refused our key."); | |
521 | xfree(comment); | |
57112b5a | 522 | return 0; |
8efc0c15 | 523 | } |
5260325f | 524 | /* Otherwise, the server should respond with a challenge. */ |
525 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
526 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
527 | ||
528 | /* Get the challenge from the packet. */ | |
529 | challenge = BN_new(); | |
530 | packet_get_bignum(challenge, &clen); | |
531 | ||
532 | packet_integrity_check(plen, clen, type); | |
533 | ||
534 | debug("Received RSA challenge from server."); | |
535 | ||
536 | private_key = RSA_new(); | |
aa3378df | 537 | /* |
538 | * Load the private key. Try first with empty passphrase; if it | |
539 | * fails, ask for a passphrase. | |
540 | */ | |
5260325f | 541 | if (!load_private_key(authfile, "", private_key, NULL)) { |
542 | char buf[300]; | |
543 | snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ", | |
a408af76 | 544 | comment); |
5260325f | 545 | if (!options.batch_mode) |
546 | passphrase = read_passphrase(buf, 0); | |
547 | else { | |
548 | debug("Will not query passphrase for %.100s in batch mode.", | |
549 | comment); | |
550 | passphrase = xstrdup(""); | |
551 | } | |
8efc0c15 | 552 | |
5260325f | 553 | /* Load the authentication file using the pasphrase. */ |
554 | if (!load_private_key(authfile, passphrase, private_key, NULL)) { | |
555 | memset(passphrase, 0, strlen(passphrase)); | |
556 | xfree(passphrase); | |
557 | error("Bad passphrase."); | |
558 | ||
559 | /* Send a dummy response packet to avoid protocol error. */ | |
560 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
561 | for (i = 0; i < 16; i++) | |
562 | packet_put_char(0); | |
563 | packet_send(); | |
564 | packet_write_wait(); | |
565 | ||
566 | /* Expect the server to reject it... */ | |
567 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
568 | xfree(comment); | |
569 | return 0; | |
570 | } | |
571 | /* Destroy the passphrase. */ | |
572 | memset(passphrase, 0, strlen(passphrase)); | |
573 | xfree(passphrase); | |
574 | } | |
575 | /* We no longer need the comment. */ | |
576 | xfree(comment); | |
577 | ||
578 | /* Compute and send a response to the challenge. */ | |
579 | respond_to_rsa_challenge(challenge, private_key); | |
580 | ||
581 | /* Destroy the private key. */ | |
582 | RSA_free(private_key); | |
8efc0c15 | 583 | |
5260325f | 584 | /* We no longer need the challenge. */ |
585 | BN_clear_free(challenge); | |
586 | ||
587 | /* Wait for response from the server. */ | |
588 | type = packet_read(&plen); | |
589 | if (type == SSH_SMSG_SUCCESS) { | |
590 | debug("RSA authentication accepted by server."); | |
591 | return 1; | |
592 | } | |
593 | if (type != SSH_SMSG_FAILURE) | |
594 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
595 | debug("RSA authentication refused."); | |
596 | return 0; | |
597 | } | |
8efc0c15 | 598 | |
5260325f | 599 | /* |
600 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
601 | * authentication and RSA host authentication. | |
602 | */ | |
8efc0c15 | 603 | int |
5260325f | 604 | try_rhosts_rsa_authentication(const char *local_user, RSA * host_key) |
8efc0c15 | 605 | { |
5260325f | 606 | int type; |
607 | BIGNUM *challenge; | |
608 | int plen, clen; | |
609 | ||
610 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
611 | ||
612 | /* Tell the server that we are willing to authenticate using this key. */ | |
613 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
614 | packet_put_string(local_user, strlen(local_user)); | |
615 | packet_put_int(BN_num_bits(host_key->n)); | |
616 | packet_put_bignum(host_key->e); | |
617 | packet_put_bignum(host_key->n); | |
618 | packet_send(); | |
619 | packet_write_wait(); | |
620 | ||
621 | /* Wait for server's response. */ | |
622 | type = packet_read(&plen); | |
623 | ||
624 | /* The server responds with failure if it doesn't admit our | |
625 | .rhosts authentication or doesn't know our host key. */ | |
626 | if (type == SSH_SMSG_FAILURE) { | |
627 | debug("Server refused our rhosts authentication or host key."); | |
628 | return 0; | |
629 | } | |
630 | /* Otherwise, the server should respond with a challenge. */ | |
631 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
632 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
633 | ||
634 | /* Get the challenge from the packet. */ | |
635 | challenge = BN_new(); | |
636 | packet_get_bignum(challenge, &clen); | |
637 | ||
638 | packet_integrity_check(plen, clen, type); | |
639 | ||
640 | debug("Received RSA challenge for host key from server."); | |
641 | ||
642 | /* Compute a response to the challenge. */ | |
643 | respond_to_rsa_challenge(challenge, host_key); | |
644 | ||
645 | /* We no longer need the challenge. */ | |
646 | BN_clear_free(challenge); | |
647 | ||
648 | /* Wait for response from the server. */ | |
649 | type = packet_read(&plen); | |
650 | if (type == SSH_SMSG_SUCCESS) { | |
651 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
652 | return 1; | |
653 | } | |
654 | if (type != SSH_SMSG_FAILURE) | |
655 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
656 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
657 | return 0; | |
8efc0c15 | 658 | } |
659 | ||
660 | #ifdef KRB4 | |
5260325f | 661 | int |
662 | try_kerberos_authentication() | |
8efc0c15 | 663 | { |
5260325f | 664 | KTEXT_ST auth; /* Kerberos data */ |
665 | char *reply; | |
666 | char inst[INST_SZ]; | |
667 | char *realm; | |
668 | CREDENTIALS cred; | |
669 | int r, type, plen; | |
670 | Key_schedule schedule; | |
671 | u_long checksum, cksum; | |
672 | MSG_DAT msg_data; | |
673 | struct sockaddr_in local, foreign; | |
674 | struct stat st; | |
675 | ||
676 | /* Don't do anything if we don't have any tickets. */ | |
677 | if (stat(tkt_string(), &st) < 0) | |
678 | return 0; | |
679 | ||
680 | strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ); | |
681 | ||
682 | realm = (char *) krb_realmofhost(get_canonical_hostname()); | |
683 | if (!realm) { | |
684 | debug("Kerberos V4: no realm for %s", get_canonical_hostname()); | |
685 | return 0; | |
686 | } | |
687 | /* This can really be anything. */ | |
688 | checksum = (u_long) getpid(); | |
689 | ||
690 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); | |
691 | if (r != KSUCCESS) { | |
692 | debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]); | |
693 | return 0; | |
694 | } | |
695 | /* Get session key to decrypt the server's reply with. */ | |
696 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
697 | if (r != KSUCCESS) { | |
698 | debug("get_cred failed: %s", krb_err_txt[r]); | |
699 | return 0; | |
700 | } | |
701 | des_key_sched((des_cblock *) cred.session, schedule); | |
702 | ||
703 | /* Send authentication info to server. */ | |
704 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
705 | packet_put_string((char *) auth.dat, auth.length); | |
706 | packet_send(); | |
707 | packet_write_wait(); | |
708 | ||
709 | /* Zero the buffer. */ | |
710 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
711 | ||
712 | r = sizeof(local); | |
713 | memset(&local, 0, sizeof(local)); | |
714 | if (getsockname(packet_get_connection_in(), | |
715 | (struct sockaddr *) & local, &r) < 0) | |
716 | debug("getsockname failed: %s", strerror(errno)); | |
717 | ||
718 | r = sizeof(foreign); | |
719 | memset(&foreign, 0, sizeof(foreign)); | |
720 | if (getpeername(packet_get_connection_in(), | |
721 | (struct sockaddr *) & foreign, &r) < 0) { | |
722 | debug("getpeername failed: %s", strerror(errno)); | |
723 | fatal_cleanup(); | |
724 | } | |
725 | /* Get server reply. */ | |
726 | type = packet_read(&plen); | |
727 | switch (type) { | |
728 | case SSH_SMSG_FAILURE: | |
729 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
730 | debug("Kerberos V4 authentication failed."); | |
731 | return 0; | |
732 | break; | |
733 | ||
734 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
735 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
736 | debug("Kerberos V4 authentication accepted."); | |
737 | ||
738 | /* Get server's response. */ | |
739 | reply = packet_get_string((unsigned int *) &auth.length); | |
740 | memcpy(auth.dat, reply, auth.length); | |
741 | xfree(reply); | |
742 | ||
743 | packet_integrity_check(plen, 4 + auth.length, type); | |
744 | ||
aa3378df | 745 | /* |
746 | * If his response isn't properly encrypted with the session | |
747 | * key, and the decrypted checksum fails to match, he's | |
748 | * bogus. Bail out. | |
749 | */ | |
5260325f | 750 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, |
751 | &foreign, &local, &msg_data); | |
752 | if (r != KSUCCESS) { | |
753 | debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]); | |
754 | packet_disconnect("Kerberos V4 challenge failed!"); | |
755 | } | |
756 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
757 | (void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum)); | |
758 | cksum = ntohl(cksum); | |
759 | ||
760 | /* If it matches, we're golden. */ | |
761 | if (cksum == checksum + 1) { | |
762 | debug("Kerberos V4 challenge successful."); | |
763 | return 1; | |
764 | } else | |
765 | packet_disconnect("Kerberos V4 challenge failed!"); | |
766 | break; | |
767 | ||
768 | default: | |
769 | packet_disconnect("Protocol error on Kerberos V4 response: %d", type); | |
770 | } | |
771 | return 0; | |
8efc0c15 | 772 | } |
5260325f | 773 | |
8efc0c15 | 774 | #endif /* KRB4 */ |
775 | ||
776 | #ifdef AFS | |
5260325f | 777 | int |
778 | send_kerberos_tgt() | |
8efc0c15 | 779 | { |
5260325f | 780 | CREDENTIALS *creds; |
781 | char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; | |
782 | int r, type, plen; | |
783 | unsigned char buffer[8192]; | |
784 | struct stat st; | |
785 | ||
786 | /* Don't do anything if we don't have any tickets. */ | |
787 | if (stat(tkt_string(), &st) < 0) | |
788 | return 0; | |
789 | ||
790 | creds = xmalloc(sizeof(*creds)); | |
791 | ||
792 | if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) { | |
793 | debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]); | |
794 | return 0; | |
795 | } | |
796 | if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) { | |
797 | debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]); | |
798 | return 0; | |
799 | } | |
800 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { | |
801 | debug("Kerberos V4 ticket expired: %s", TKT_FILE); | |
802 | return 0; | |
803 | } | |
804 | creds_to_radix(creds, buffer); | |
805 | xfree(creds); | |
806 | ||
807 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
808 | packet_put_string((char *) buffer, strlen(buffer)); | |
809 | packet_send(); | |
810 | packet_write_wait(); | |
811 | ||
812 | type = packet_read(&plen); | |
813 | ||
814 | if (type == SSH_SMSG_FAILURE) | |
815 | debug("Kerberos TGT for realm %s rejected.", prealm); | |
816 | else if (type != SSH_SMSG_SUCCESS) | |
817 | packet_disconnect("Protocol error on Kerberos TGT response: %d", type); | |
818 | ||
819 | return 1; | |
8efc0c15 | 820 | } |
821 | ||
5260325f | 822 | void |
823 | send_afs_tokens(void) | |
8efc0c15 | 824 | { |
5260325f | 825 | CREDENTIALS creds; |
826 | struct ViceIoctl parms; | |
827 | struct ClearToken ct; | |
828 | int i, type, len, plen; | |
829 | char buf[2048], *p, *server_cell; | |
830 | unsigned char buffer[8192]; | |
831 | ||
832 | /* Move over ktc_GetToken, here's something leaner. */ | |
833 | for (i = 0; i < 100; i++) { /* just in case */ | |
834 | parms.in = (char *) &i; | |
835 | parms.in_size = sizeof(i); | |
836 | parms.out = buf; | |
837 | parms.out_size = sizeof(buf); | |
838 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
839 | break; | |
840 | p = buf; | |
841 | ||
842 | /* Get secret token. */ | |
843 | memcpy(&creds.ticket_st.length, p, sizeof(unsigned int)); | |
844 | if (creds.ticket_st.length > MAX_KTXT_LEN) | |
845 | break; | |
846 | p += sizeof(unsigned int); | |
847 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); | |
848 | p += creds.ticket_st.length; | |
849 | ||
850 | /* Get clear token. */ | |
851 | memcpy(&len, p, sizeof(len)); | |
852 | if (len != sizeof(struct ClearToken)) | |
853 | break; | |
854 | p += sizeof(len); | |
855 | memcpy(&ct, p, len); | |
856 | p += len; | |
857 | p += sizeof(len); /* primary flag */ | |
858 | server_cell = p; | |
859 | ||
860 | /* Flesh out our credentials. */ | |
861 | strlcpy(creds.service, "afs", sizeof creds.service); | |
862 | creds.instance[0] = '\0'; | |
863 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
864 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
865 | creds.issue_date = ct.BeginTimestamp; | |
866 | creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp); | |
867 | creds.kvno = ct.AuthHandle; | |
868 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
869 | creds.pinst[0] = '\0'; | |
870 | ||
871 | /* Encode token, ship it off. */ | |
872 | if (!creds_to_radix(&creds, buffer)) | |
873 | break; | |
874 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
875 | packet_put_string((char *) buffer, strlen(buffer)); | |
876 | packet_send(); | |
877 | packet_write_wait(); | |
878 | ||
879 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
880 | Victor? */ | |
881 | type = packet_read(&plen); | |
882 | ||
883 | if (type == SSH_SMSG_FAILURE) | |
884 | debug("AFS token for cell %s rejected.", server_cell); | |
885 | else if (type != SSH_SMSG_SUCCESS) | |
886 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
887 | } | |
8efc0c15 | 888 | } |
8efc0c15 | 889 | |
5260325f | 890 | #endif /* AFS */ |
8efc0c15 | 891 | |
57112b5a | 892 | /* |
893 | * Tries to authenticate with any string-based challenge/response system. | |
894 | * Note that the client code is not tied to s/key or TIS. | |
895 | */ | |
896 | int | |
897 | try_skey_authentication() | |
898 | { | |
899 | int type, i, payload_len; | |
900 | char *challenge, *response; | |
901 | ||
902 | debug("Doing skey authentication."); | |
903 | ||
904 | /* request a challenge */ | |
905 | packet_start(SSH_CMSG_AUTH_TIS); | |
906 | packet_send(); | |
907 | packet_write_wait(); | |
908 | ||
909 | type = packet_read(&payload_len); | |
910 | if (type != SSH_SMSG_FAILURE && | |
911 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
912 | packet_disconnect("Protocol error: got %d in response " | |
913 | "to skey-auth", type); | |
914 | } | |
915 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
916 | debug("No challenge for skey authentication."); | |
917 | return 0; | |
918 | } | |
919 | challenge = packet_get_string(&payload_len); | |
920 | if (options.cipher == SSH_CIPHER_NONE) | |
921 | log("WARNING: Encryption is disabled! " | |
922 | "Reponse will be transmitted in clear text."); | |
923 | fprintf(stderr, "%s\n", challenge); | |
924 | fflush(stderr); | |
925 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
926 | if (i != 0) | |
927 | error("Permission denied, please try again."); | |
928 | response = read_passphrase("Response: ", 0); | |
929 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); | |
930 | packet_put_string(response, strlen(response)); | |
931 | memset(response, 0, strlen(response)); | |
932 | xfree(response); | |
933 | packet_send(); | |
934 | packet_write_wait(); | |
935 | type = packet_read(&payload_len); | |
936 | if (type == SSH_SMSG_SUCCESS) | |
937 | return 1; | |
938 | if (type != SSH_SMSG_FAILURE) | |
939 | packet_disconnect("Protocol error: got %d in response " | |
940 | "to skey-auth-reponse", type); | |
941 | } | |
942 | /* failure */ | |
943 | return 0; | |
944 | } | |
945 | ||
946 | /* | |
947 | * Tries to authenticate with plain passwd authentication. | |
948 | */ | |
949 | int | |
950 | try_password_authentication(char *prompt) | |
951 | { | |
952 | int type, i, payload_len; | |
953 | char *password; | |
954 | ||
955 | debug("Doing password authentication."); | |
956 | if (options.cipher == SSH_CIPHER_NONE) | |
957 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
958 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
959 | if (i != 0) | |
960 | error("Permission denied, please try again."); | |
961 | password = read_passphrase(prompt, 0); | |
962 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
963 | packet_put_string(password, strlen(password)); | |
964 | memset(password, 0, strlen(password)); | |
965 | xfree(password); | |
966 | packet_send(); | |
967 | packet_write_wait(); | |
968 | ||
969 | type = packet_read(&payload_len); | |
970 | if (type == SSH_SMSG_SUCCESS) | |
971 | return 1; | |
972 | if (type != SSH_SMSG_FAILURE) | |
973 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
974 | } | |
975 | /* failure */ | |
976 | return 0; | |
977 | } | |
978 | ||
5260325f | 979 | /* |
980 | * Waits for the server identification string, and sends our own | |
981 | * identification string. | |
982 | */ | |
983 | void | |
984 | ssh_exchange_identification() | |
8efc0c15 | 985 | { |
5260325f | 986 | char buf[256], remote_version[256]; /* must be same size! */ |
987 | int remote_major, remote_minor, i; | |
988 | int connection_in = packet_get_connection_in(); | |
989 | int connection_out = packet_get_connection_out(); | |
5260325f | 990 | |
991 | /* Read other side\'s version identification. */ | |
992 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
993 | if (read(connection_in, &buf[i], 1) != 1) | |
994 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); | |
995 | if (buf[i] == '\r') { | |
996 | buf[i] = '\n'; | |
997 | buf[i + 1] = 0; | |
998 | break; | |
999 | } | |
1000 | if (buf[i] == '\n') { | |
1001 | buf[i + 1] = 0; | |
1002 | break; | |
1003 | } | |
8efc0c15 | 1004 | } |
5260325f | 1005 | buf[sizeof(buf) - 1] = 0; |
1006 | ||
aa3378df | 1007 | /* |
1008 | * Check that the versions match. In future this might accept | |
1009 | * several versions and set appropriate flags to handle them. | |
1010 | */ | |
5260325f | 1011 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
1012 | remote_version) != 3) | |
1013 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
1014 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
1015 | remote_major, remote_minor, remote_version); | |
1016 | ||
1017 | /* Check if the remote protocol version is too old. */ | |
1018 | if (remote_major == 1 && remote_minor < 3) | |
1019 | fatal("Remote machine has too old SSH software version."); | |
1020 | ||
1021 | /* We speak 1.3, too. */ | |
1022 | if (remote_major == 1 && remote_minor == 3) { | |
1023 | enable_compat13(); | |
e02735bb | 1024 | if (options.forward_agent && strcmp(remote_version, "OpenSSH-1.1") != 0) { |
5260325f | 1025 | log("Agent forwarding disabled, remote version '%s' is not compatible.", |
1026 | remote_version); | |
1027 | options.forward_agent = 0; | |
1028 | } | |
8efc0c15 | 1029 | } |
8efc0c15 | 1030 | #if 0 |
aa3378df | 1031 | /* |
1032 | * Removed for now, to permit compatibility with latter versions. The | |
1033 | * server will reject our version and disconnect if it doesn't | |
1034 | * support it. | |
1035 | */ | |
5260325f | 1036 | if (remote_major != PROTOCOL_MAJOR) |
1037 | fatal("Protocol major versions differ: %d vs. %d", | |
1038 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 1039 | #endif |
1040 | ||
5260325f | 1041 | /* Send our own protocol version identification. */ |
1042 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
a408af76 | 1043 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); |
1044 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) | |
5260325f | 1045 | fatal("write: %.100s", strerror(errno)); |
8efc0c15 | 1046 | } |
1047 | ||
1048 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
1049 | ||
5260325f | 1050 | int |
1051 | read_yes_or_no(const char *prompt, int defval) | |
8efc0c15 | 1052 | { |
5260325f | 1053 | char buf[1024]; |
1054 | FILE *f; | |
1055 | int retval = -1; | |
1056 | ||
1057 | if (isatty(0)) | |
1058 | f = stdin; | |
1059 | else | |
1060 | f = fopen("/dev/tty", "rw"); | |
1061 | ||
1062 | if (f == NULL) | |
1063 | return 0; | |
1064 | ||
1065 | fflush(stdout); | |
1066 | ||
1067 | while (1) { | |
1068 | fprintf(stderr, "%s", prompt); | |
1069 | if (fgets(buf, sizeof(buf), f) == NULL) { | |
1070 | /* Print a newline (the prompt probably didn\'t have one). */ | |
1071 | fprintf(stderr, "\n"); | |
1072 | strlcpy(buf, "no", sizeof buf); | |
1073 | } | |
1074 | /* Remove newline from response. */ | |
1075 | if (strchr(buf, '\n')) | |
1076 | *strchr(buf, '\n') = 0; | |
1077 | ||
1078 | if (buf[0] == 0) | |
1079 | retval = defval; | |
1080 | if (strcmp(buf, "yes") == 0) | |
1081 | retval = 1; | |
1082 | if (strcmp(buf, "no") == 0) | |
1083 | retval = 0; | |
1084 | ||
1085 | if (retval != -1) { | |
1086 | if (f != stdin) | |
1087 | fclose(f); | |
1088 | return retval; | |
1089 | } | |
8efc0c15 | 1090 | } |
8efc0c15 | 1091 | } |
1092 | ||
5260325f | 1093 | /* |
95f1eccc | 1094 | * check whether the supplied host key is valid, return only if ok. |
5260325f | 1095 | */ |
95f1eccc | 1096 | |
5260325f | 1097 | void |
95f1eccc | 1098 | check_host_key(char *host, |
1099 | struct sockaddr_in *hostaddr, | |
1100 | RSA *host_key) | |
8efc0c15 | 1101 | { |
95f1eccc | 1102 | RSA *file_key; |
1103 | char *ip = NULL; | |
5260325f | 1104 | char hostline[1000], *hostp; |
5260325f | 1105 | HostStatus host_status; |
1106 | HostStatus ip_status; | |
1107 | int host_ip_differ = 0; | |
1108 | int local = (ntohl(hostaddr->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; | |
5260325f | 1109 | |
57112b5a | 1110 | /* |
1111 | * Turn off check_host_ip for proxy connects, since | |
1112 | * we don't have the remote ip-address | |
1113 | */ | |
1114 | if (options.proxy_command != NULL && options.check_host_ip) | |
1115 | options.check_host_ip = 0; | |
1116 | ||
5260325f | 1117 | if (options.check_host_ip) |
1118 | ip = xstrdup(inet_ntoa(hostaddr->sin_addr)); | |
1119 | ||
95f1eccc | 1120 | /* |
1121 | * Store the host key from the known host file in here so that we can | |
1122 | * compare it with the key for the IP address. | |
1123 | */ | |
5260325f | 1124 | file_key = RSA_new(); |
1125 | file_key->n = BN_new(); | |
1126 | file_key->e = BN_new(); | |
1127 | ||
aa3378df | 1128 | /* |
1129 | * Check if the host key is present in the user\'s list of known | |
1130 | * hosts or in the systemwide list. | |
1131 | */ | |
5260325f | 1132 | host_status = check_host_in_hostfile(options.user_hostfile, host, |
1133 | host_key->e, host_key->n, | |
1134 | file_key->e, file_key->n); | |
1135 | if (host_status == HOST_NEW) | |
1136 | host_status = check_host_in_hostfile(options.system_hostfile, host, | |
1137 | host_key->e, host_key->n, | |
1138 | file_key->e, file_key->n); | |
aa3378df | 1139 | /* |
1140 | * Force accepting of the host key for localhost and 127.0.0.1. The | |
1141 | * problem is that if the home directory is NFS-mounted to multiple | |
1142 | * machines, localhost will refer to a different machine in each of | |
1143 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
1144 | * essentially disables host authentication for localhost; however, | |
1145 | * this is probably not a real problem. | |
1146 | */ | |
5260325f | 1147 | if (local) { |
1148 | debug("Forcing accepting of host key for localhost."); | |
1149 | host_status = HOST_OK; | |
1150 | } | |
aa3378df | 1151 | /* |
1152 | * Also perform check for the ip address, skip the check if we are | |
1153 | * localhost or the hostname was an ip address to begin with | |
1154 | */ | |
5260325f | 1155 | if (options.check_host_ip && !local && strcmp(host, ip)) { |
1156 | RSA *ip_key = RSA_new(); | |
1157 | ip_key->n = BN_new(); | |
1158 | ip_key->e = BN_new(); | |
1159 | ip_status = check_host_in_hostfile(options.user_hostfile, ip, | |
1160 | host_key->e, host_key->n, | |
1161 | ip_key->e, ip_key->n); | |
1162 | ||
1163 | if (ip_status == HOST_NEW) | |
1164 | ip_status = check_host_in_hostfile(options.system_hostfile, ip, | |
1165 | host_key->e, host_key->n, | |
1166 | ip_key->e, ip_key->n); | |
1167 | if (host_status == HOST_CHANGED && | |
1168 | (ip_status != HOST_CHANGED || | |
1169 | (BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n)))) | |
1170 | host_ip_differ = 1; | |
1171 | ||
1172 | RSA_free(ip_key); | |
1173 | } else | |
1174 | ip_status = host_status; | |
1175 | ||
1176 | RSA_free(file_key); | |
1177 | ||
1178 | switch (host_status) { | |
1179 | case HOST_OK: | |
1180 | /* The host is known and the key matches. */ | |
1181 | debug("Host '%.200s' is known and matches the host key.", host); | |
1182 | if (options.check_host_ip) { | |
1183 | if (ip_status == HOST_NEW) { | |
1184 | if (!add_host_to_hostfile(options.user_hostfile, ip, | |
1185 | host_key->e, host_key->n)) | |
1186 | log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).", | |
1187 | ip, options.user_hostfile); | |
1188 | else | |
1189 | log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.", | |
1190 | ip); | |
1191 | } else if (ip_status != HOST_OK) | |
1192 | log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'", | |
1193 | host, ip); | |
1194 | } | |
1195 | break; | |
1196 | case HOST_NEW: | |
1197 | /* The host is new. */ | |
1198 | if (options.strict_host_key_checking == 1) { | |
1199 | /* User has requested strict host key checking. We will not add the host key | |
1200 | automatically. The only alternative left is to abort. */ | |
1201 | fatal("No host key is known for %.200s and you have requested strict checking.", host); | |
1202 | } else if (options.strict_host_key_checking == 2) { | |
1203 | /* The default */ | |
1204 | char prompt[1024]; | |
1205 | char *fp = fingerprint(host_key->e, host_key->n); | |
1206 | snprintf(prompt, sizeof(prompt), | |
a408af76 | 1207 | "The authenticity of host '%.200s' can't be established.\n" |
1208 | "Key fingerprint is %d %s.\n" | |
1209 | "Are you sure you want to continue connecting (yes/no)? ", | |
1210 | host, BN_num_bits(host_key->n), fp); | |
5260325f | 1211 | if (!read_yes_or_no(prompt, -1)) |
1212 | fatal("Aborted by user!\n"); | |
1213 | } | |
1214 | if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) { | |
1215 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); | |
1216 | hostp = hostline; | |
1217 | } else | |
1218 | hostp = host; | |
1219 | ||
1220 | /* If not in strict mode, add the key automatically to the local known_hosts file. */ | |
1221 | if (!add_host_to_hostfile(options.user_hostfile, hostp, | |
1222 | host_key->e, host_key->n)) | |
1223 | log("Failed to add the host to the list of known hosts (%.500s).", | |
1224 | options.user_hostfile); | |
1225 | else | |
1226 | log("Warning: Permanently added '%.200s' to the list of known hosts.", | |
1227 | hostp); | |
1228 | break; | |
1229 | case HOST_CHANGED: | |
1230 | if (options.check_host_ip && host_ip_differ) { | |
1231 | char *msg; | |
1232 | if (ip_status == HOST_NEW) | |
1233 | msg = "is unknown"; | |
1234 | else if (ip_status == HOST_OK) | |
1235 | msg = "is unchanged"; | |
1236 | else | |
1237 | msg = "has a different value"; | |
1238 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1239 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
1240 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1241 | error("The host key for %s has changed,", host); | |
1242 | error("and the key for the according IP address %s", ip); | |
1243 | error("%s. This could either mean that", msg); | |
1244 | error("DNS SPOOFING is happening or the IP address for the host"); | |
1245 | error("and its host key have changed at the same time"); | |
1246 | } | |
1247 | /* The host key has changed. */ | |
1248 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
ae2f7af7 | 1249 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
5260325f | 1250 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
1251 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1252 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1253 | error("It is also possible that the host key has just been changed."); | |
1254 | error("Please contact your system administrator."); | |
1255 | error("Add correct host key in %.100s to get rid of this message.", | |
1256 | options.user_hostfile); | |
1257 | ||
aa3378df | 1258 | /* |
1259 | * If strict host key checking is in use, the user will have | |
1260 | * to edit the key manually and we can only abort. | |
1261 | */ | |
5260325f | 1262 | if (options.strict_host_key_checking) |
1263 | fatal("Host key for %.200s has changed and you have requested strict checking.", host); | |
1264 | ||
aa3378df | 1265 | /* |
1266 | * If strict host key checking has not been requested, allow | |
1267 | * the connection but without password authentication or | |
1268 | * agent forwarding. | |
1269 | */ | |
5260325f | 1270 | if (options.password_authentication) { |
1271 | error("Password authentication is disabled to avoid trojan horses."); | |
1272 | options.password_authentication = 0; | |
1273 | } | |
1274 | if (options.forward_agent) { | |
1275 | error("Agent forwarding is disabled to avoid trojan horses."); | |
1276 | options.forward_agent = 0; | |
1277 | } | |
aa3378df | 1278 | /* |
1279 | * XXX Should permit the user to change to use the new id. | |
1280 | * This could be done by converting the host key to an | |
1281 | * identifying sentence, tell that the host identifies itself | |
1282 | * by that sentence, and ask the user if he/she whishes to | |
1283 | * accept the authentication. | |
1284 | */ | |
5260325f | 1285 | break; |
1286 | } | |
5260325f | 1287 | if (options.check_host_ip) |
1288 | xfree(ip); | |
95f1eccc | 1289 | } |
1290 | ||
1291 | /* | |
1292 | * Starts a dialog with the server, and authenticates the current user on the | |
1293 | * server. This does not need any extra privileges. The basic connection | |
1294 | * to the server must already have been established before this is called. | |
1295 | * User is the remote user; if it is NULL, the current local user name will | |
1296 | * be used. Anonymous indicates that no rhosts authentication will be used. | |
1297 | * If login fails, this function prints an error and never returns. | |
1298 | * This function does not require super-user privileges. | |
1299 | */ | |
1300 | void | |
1301 | ssh_login(int host_key_valid, | |
1302 | RSA *own_host_key, | |
1303 | const char *orighost, | |
1304 | struct sockaddr_in *hostaddr, | |
1305 | uid_t original_real_uid) | |
1306 | { | |
1307 | int i, type; | |
1308 | struct passwd *pw; | |
1309 | BIGNUM *key; | |
1310 | RSA *host_key; | |
1311 | RSA *public_key; | |
1312 | int bits, rbits; | |
1313 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
1314 | const char *server_user, *local_user; | |
1315 | char *host, *cp; | |
1316 | unsigned char check_bytes[8]; | |
1317 | unsigned int supported_ciphers, supported_authentications; | |
1318 | unsigned int server_flags, client_flags; | |
1319 | int payload_len, clen, sum_len = 0; | |
1320 | u_int32_t rand = 0; | |
1321 | ||
1322 | /* Convert the user-supplied hostname into all lowercase. */ | |
1323 | host = xstrdup(orighost); | |
1324 | for (cp = host; *cp; cp++) | |
1325 | if (isupper(*cp)) | |
1326 | *cp = tolower(*cp); | |
1327 | ||
1328 | /* Exchange protocol version identification strings with the server. */ | |
1329 | ssh_exchange_identification(); | |
1330 | ||
1331 | /* Put the connection into non-blocking mode. */ | |
1332 | packet_set_nonblocking(); | |
1333 | ||
1334 | /* Get local user name. Use it as server user if no user name was given. */ | |
1335 | pw = getpwuid(original_real_uid); | |
1336 | if (!pw) | |
1337 | fatal("User id %d not found from user database.", original_real_uid); | |
1338 | local_user = xstrdup(pw->pw_name); | |
1339 | server_user = options.user ? options.user : local_user; | |
1340 | ||
1341 | debug("Waiting for server public key."); | |
1342 | ||
1343 | /* Wait for a public key packet from the server. */ | |
1344 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
1345 | ||
1346 | /* Get check bytes from the packet. */ | |
1347 | for (i = 0; i < 8; i++) | |
1348 | check_bytes[i] = packet_get_char(); | |
1349 | ||
1350 | /* Get the public key. */ | |
1351 | public_key = RSA_new(); | |
1352 | bits = packet_get_int();/* bits */ | |
1353 | public_key->e = BN_new(); | |
1354 | packet_get_bignum(public_key->e, &clen); | |
1355 | sum_len += clen; | |
1356 | public_key->n = BN_new(); | |
1357 | packet_get_bignum(public_key->n, &clen); | |
1358 | sum_len += clen; | |
1359 | ||
1360 | rbits = BN_num_bits(public_key->n); | |
1361 | if (bits != rbits) { | |
1362 | log("Warning: Server lies about size of server public key: " | |
1363 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1364 | log("Warning: This may be due to an old implementation of ssh."); | |
1365 | } | |
1366 | /* Get the host key. */ | |
1367 | host_key = RSA_new(); | |
1368 | bits = packet_get_int();/* bits */ | |
1369 | host_key->e = BN_new(); | |
1370 | packet_get_bignum(host_key->e, &clen); | |
1371 | sum_len += clen; | |
1372 | host_key->n = BN_new(); | |
1373 | packet_get_bignum(host_key->n, &clen); | |
1374 | sum_len += clen; | |
1375 | ||
1376 | rbits = BN_num_bits(host_key->n); | |
1377 | if (bits != rbits) { | |
1378 | log("Warning: Server lies about size of server host key: " | |
1379 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1380 | log("Warning: This may be due to an old implementation of ssh."); | |
1381 | } | |
1382 | ||
1383 | /* Get protocol flags. */ | |
1384 | server_flags = packet_get_int(); | |
1385 | packet_set_protocol_flags(server_flags); | |
1386 | ||
1387 | supported_ciphers = packet_get_int(); | |
1388 | supported_authentications = packet_get_int(); | |
1389 | ||
1390 | debug("Received server public key (%d bits) and host key (%d bits).", | |
1391 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
1392 | ||
1393 | packet_integrity_check(payload_len, | |
1394 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
1395 | SSH_SMSG_PUBLIC_KEY); | |
1396 | ||
1397 | check_host_key(host, hostaddr, host_key); | |
1398 | ||
1399 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; | |
1400 | ||
1401 | compute_session_id(session_id, check_bytes, host_key->n, public_key->n); | |
5260325f | 1402 | |
1403 | /* Generate a session key. */ | |
1404 | arc4random_stir(); | |
1405 | ||
aa3378df | 1406 | /* |
1407 | * Generate an encryption key for the session. The key is a 256 bit | |
1408 | * random number, interpreted as a 32-byte key, with the least | |
1409 | * significant 8 bits being the first byte of the key. | |
1410 | */ | |
5260325f | 1411 | for (i = 0; i < 32; i++) { |
1412 | if (i % 4 == 0) | |
1413 | rand = arc4random(); | |
1414 | session_key[i] = rand & 0xff; | |
1415 | rand >>= 8; | |
1416 | } | |
1417 | ||
aa3378df | 1418 | /* |
1419 | * According to the protocol spec, the first byte of the session key | |
1420 | * is the highest byte of the integer. The session key is xored with | |
1421 | * the first 16 bytes of the session id. | |
1422 | */ | |
5260325f | 1423 | key = BN_new(); |
1424 | BN_set_word(key, 0); | |
1425 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1426 | BN_lshift(key, key, 8); | |
1427 | if (i < 16) | |
1428 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1429 | else | |
1430 | BN_add_word(key, session_key[i]); | |
1431 | } | |
1432 | ||
aa3378df | 1433 | /* |
1434 | * Encrypt the integer using the public key and host key of the | |
1435 | * server (key with smaller modulus first). | |
1436 | */ | |
5260325f | 1437 | if (BN_cmp(public_key->n, host_key->n) < 0) { |
1438 | /* Public key has smaller modulus. */ | |
1439 | if (BN_num_bits(host_key->n) < | |
1440 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1441 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1442 | "SSH_KEY_BITS_RESERVED %d", | |
1443 | BN_num_bits(host_key->n), | |
1444 | BN_num_bits(public_key->n), | |
1445 | SSH_KEY_BITS_RESERVED); | |
1446 | } | |
1447 | rsa_public_encrypt(key, key, public_key); | |
1448 | rsa_public_encrypt(key, key, host_key); | |
1449 | } else { | |
1450 | /* Host key has smaller modulus (or they are equal). */ | |
1451 | if (BN_num_bits(public_key->n) < | |
1452 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1453 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1454 | "SSH_KEY_BITS_RESERVED %d", | |
1455 | BN_num_bits(public_key->n), | |
1456 | BN_num_bits(host_key->n), | |
1457 | SSH_KEY_BITS_RESERVED); | |
1458 | } | |
1459 | rsa_public_encrypt(key, key, host_key); | |
1460 | rsa_public_encrypt(key, key, public_key); | |
1461 | } | |
1462 | ||
1463 | if (options.cipher == SSH_CIPHER_NOT_SET) { | |
1464 | if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default)) | |
1465 | options.cipher = ssh_cipher_default; | |
1466 | else { | |
1467 | debug("Cipher %s not supported, using %.100s instead.", | |
1468 | cipher_name(ssh_cipher_default), | |
1469 | cipher_name(SSH_FALLBACK_CIPHER)); | |
1470 | options.cipher = SSH_FALLBACK_CIPHER; | |
1471 | } | |
1472 | } | |
1473 | /* Check that the selected cipher is supported. */ | |
1474 | if (!(supported_ciphers & (1 << options.cipher))) | |
1475 | fatal("Selected cipher type %.100s not supported by server.", | |
1476 | cipher_name(options.cipher)); | |
1477 | ||
1478 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1479 | ||
1480 | /* Send the encrypted session key to the server. */ | |
1481 | packet_start(SSH_CMSG_SESSION_KEY); | |
1482 | packet_put_char(options.cipher); | |
1483 | ||
1484 | /* Send the check bytes back to the server. */ | |
1485 | for (i = 0; i < 8; i++) | |
1486 | packet_put_char(check_bytes[i]); | |
1487 | ||
1488 | /* Send the encrypted encryption key. */ | |
1489 | packet_put_bignum(key); | |
1490 | ||
1491 | /* Send protocol flags. */ | |
95f1eccc | 1492 | packet_put_int(client_flags); |
5260325f | 1493 | |
1494 | /* Send the packet now. */ | |
8efc0c15 | 1495 | packet_send(); |
1496 | packet_write_wait(); | |
5260325f | 1497 | |
1498 | /* Destroy the session key integer and the public keys since we no longer need them. */ | |
1499 | BN_clear_free(key); | |
1500 | RSA_free(public_key); | |
1501 | RSA_free(host_key); | |
1502 | ||
1503 | debug("Sent encrypted session key."); | |
1504 | ||
1505 | /* Set the encryption key. */ | |
1506 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1507 | ||
1508 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1509 | memset(session_key, 0, sizeof(session_key)); | |
1510 | ||
aa3378df | 1511 | /* |
1512 | * Expect a success message from the server. Note that this message | |
1513 | * will be received in encrypted form. | |
1514 | */ | |
5260325f | 1515 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); |
1516 | ||
1517 | debug("Received encrypted confirmation."); | |
1518 | ||
1519 | /* Send the name of the user to log in as on the server. */ | |
1520 | packet_start(SSH_CMSG_USER); | |
1521 | packet_put_string(server_user, strlen(server_user)); | |
1522 | packet_send(); | |
1523 | packet_write_wait(); | |
1524 | ||
aa3378df | 1525 | /* |
1526 | * The server should respond with success if no authentication is | |
1527 | * needed (the user has no password). Otherwise the server responds | |
1528 | * with failure. | |
1529 | */ | |
8efc0c15 | 1530 | type = packet_read(&payload_len); |
5260325f | 1531 | |
1532 | /* check whether the connection was accepted without authentication. */ | |
8efc0c15 | 1533 | if (type == SSH_SMSG_SUCCESS) |
5260325f | 1534 | return; |
8efc0c15 | 1535 | if (type != SSH_SMSG_FAILURE) |
5260325f | 1536 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", |
1537 | type); | |
1538 | ||
1539 | #ifdef AFS | |
1540 | /* Try Kerberos tgt passing if the server supports it. */ | |
1541 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1542 | options.kerberos_tgt_passing) { | |
1543 | if (options.cipher == SSH_CIPHER_NONE) | |
1544 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1545 | (void) send_kerberos_tgt(); | |
1546 | } | |
1547 | /* Try AFS token passing if the server supports it. */ | |
1548 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1549 | options.afs_token_passing && k_hasafs()) { | |
1550 | if (options.cipher == SSH_CIPHER_NONE) | |
1551 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1552 | send_afs_tokens(); | |
1553 | } | |
1554 | #endif /* AFS */ | |
8efc0c15 | 1555 | |
5260325f | 1556 | #ifdef KRB4 |
1557 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1558 | options.kerberos_authentication) { | |
1559 | debug("Trying Kerberos authentication."); | |
1560 | if (try_kerberos_authentication()) { | |
1561 | /* The server should respond with success or failure. */ | |
1562 | type = packet_read(&payload_len); | |
1563 | if (type == SSH_SMSG_SUCCESS) | |
1564 | return; | |
1565 | if (type != SSH_SMSG_FAILURE) | |
1566 | packet_disconnect("Protocol error: got %d in response to Kerberos auth", type); | |
1567 | } | |
1568 | } | |
1569 | #endif /* KRB4 */ | |
1570 | ||
aa3378df | 1571 | /* |
1572 | * Use rhosts authentication if running in privileged socket and we | |
1573 | * do not wish to remain anonymous. | |
1574 | */ | |
5260325f | 1575 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && |
1576 | options.rhosts_authentication) { | |
1577 | debug("Trying rhosts authentication."); | |
1578 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
1579 | packet_put_string(local_user, strlen(local_user)); | |
1580 | packet_send(); | |
1581 | packet_write_wait(); | |
1582 | ||
1583 | /* The server should respond with success or failure. */ | |
1584 | type = packet_read(&payload_len); | |
1585 | if (type == SSH_SMSG_SUCCESS) | |
1586 | return; | |
1587 | if (type != SSH_SMSG_FAILURE) | |
1588 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1589 | type); | |
1590 | } | |
aa3378df | 1591 | /* |
1592 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1593 | * authentication. | |
1594 | */ | |
5260325f | 1595 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && |
1596 | options.rhosts_rsa_authentication && host_key_valid) { | |
1597 | if (try_rhosts_rsa_authentication(local_user, own_host_key)) | |
1598 | return; | |
1599 | } | |
1600 | /* Try RSA authentication if the server supports it. */ | |
1601 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1602 | options.rsa_authentication) { | |
aa3378df | 1603 | /* |
1604 | * Try RSA authentication using the authentication agent. The | |
1605 | * agent is tried first because no passphrase is needed for | |
1606 | * it, whereas identity files may require passphrases. | |
1607 | */ | |
5260325f | 1608 | if (try_agent_authentication()) |
1609 | return; | |
1610 | ||
1611 | /* Try RSA authentication for each identity. */ | |
1612 | for (i = 0; i < options.num_identity_files; i++) | |
57112b5a | 1613 | if (try_rsa_authentication(options.identity_files[i])) |
5260325f | 1614 | return; |
1615 | } | |
1616 | /* Try skey authentication if the server supports it. */ | |
1617 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && | |
1618 | options.skey_authentication && !options.batch_mode) { | |
57112b5a | 1619 | if (try_skey_authentication()) |
1620 | return; | |
5260325f | 1621 | } |
1622 | /* Try password authentication if the server supports it. */ | |
1623 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1624 | options.password_authentication && !options.batch_mode) { | |
1625 | char prompt[80]; | |
a408af76 | 1626 | |
57112b5a | 1627 | snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
a408af76 | 1628 | server_user, host); |
57112b5a | 1629 | if (try_password_authentication(prompt)) |
1630 | return; | |
5260325f | 1631 | } |
1632 | /* All authentication methods have failed. Exit with an error message. */ | |
1633 | fatal("Permission denied."); | |
1634 | /* NOTREACHED */ | |
8efc0c15 | 1635 | } |