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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; |
48e671d5 | 38 | extern char *__progname; |
57112b5a | 39 | |
5260325f | 40 | /* |
41 | * Connect to the given ssh server using a proxy command. | |
42 | */ | |
8efc0c15 | 43 | int |
57112b5a | 44 | ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid, |
8efc0c15 | 45 | const char *proxy_command) |
46 | { | |
5260325f | 47 | Buffer command; |
48 | const char *cp; | |
49 | char *command_string; | |
50 | int pin[2], pout[2]; | |
51 | int pid; | |
48e671d5 | 52 | char strport[NI_MAXSERV]; |
5260325f | 53 | |
54 | /* Convert the port number into a string. */ | |
48e671d5 | 55 | snprintf(strport, sizeof strport, "%hu", port); |
5260325f | 56 | |
57 | /* Build the final command string in the buffer by making the | |
58 | appropriate substitutions to the given proxy command. */ | |
59 | buffer_init(&command); | |
60 | for (cp = proxy_command; *cp; cp++) { | |
61 | if (cp[0] == '%' && cp[1] == '%') { | |
62 | buffer_append(&command, "%", 1); | |
63 | cp++; | |
64 | continue; | |
65 | } | |
66 | if (cp[0] == '%' && cp[1] == 'h') { | |
67 | buffer_append(&command, host, strlen(host)); | |
68 | cp++; | |
69 | continue; | |
70 | } | |
71 | if (cp[0] == '%' && cp[1] == 'p') { | |
48e671d5 | 72 | buffer_append(&command, strport, strlen(strport)); |
5260325f | 73 | cp++; |
74 | continue; | |
75 | } | |
76 | buffer_append(&command, cp, 1); | |
8efc0c15 | 77 | } |
5260325f | 78 | buffer_append(&command, "\0", 1); |
79 | ||
80 | /* Get the final command string. */ | |
81 | command_string = buffer_ptr(&command); | |
82 | ||
83 | /* Create pipes for communicating with the proxy. */ | |
84 | if (pipe(pin) < 0 || pipe(pout) < 0) | |
85 | fatal("Could not create pipes to communicate with the proxy: %.100s", | |
86 | strerror(errno)); | |
87 | ||
88 | debug("Executing proxy command: %.500s", command_string); | |
89 | ||
90 | /* Fork and execute the proxy command. */ | |
91 | if ((pid = fork()) == 0) { | |
92 | char *argv[10]; | |
93 | ||
94 | /* Child. Permanently give up superuser privileges. */ | |
95 | permanently_set_uid(original_real_uid); | |
96 | ||
97 | /* Redirect stdin and stdout. */ | |
98 | close(pin[1]); | |
99 | if (pin[0] != 0) { | |
100 | if (dup2(pin[0], 0) < 0) | |
101 | perror("dup2 stdin"); | |
102 | close(pin[0]); | |
103 | } | |
104 | close(pout[0]); | |
105 | if (dup2(pout[1], 1) < 0) | |
106 | perror("dup2 stdout"); | |
107 | /* Cannot be 1 because pin allocated two descriptors. */ | |
108 | close(pout[1]); | |
109 | ||
110 | /* Stderr is left as it is so that error messages get | |
111 | printed on the user's terminal. */ | |
112 | argv[0] = "/bin/sh"; | |
113 | argv[1] = "-c"; | |
114 | argv[2] = command_string; | |
115 | argv[3] = NULL; | |
116 | ||
117 | /* Execute the proxy command. Note that we gave up any | |
118 | extra privileges above. */ | |
119 | execv("/bin/sh", argv); | |
120 | perror("/bin/sh"); | |
121 | exit(1); | |
8efc0c15 | 122 | } |
5260325f | 123 | /* Parent. */ |
124 | if (pid < 0) | |
125 | fatal("fork failed: %.100s", strerror(errno)); | |
126 | ||
127 | /* Close child side of the descriptors. */ | |
128 | close(pin[0]); | |
129 | close(pout[1]); | |
130 | ||
131 | /* Free the command name. */ | |
132 | buffer_free(&command); | |
133 | ||
134 | /* Set the connection file descriptors. */ | |
135 | packet_set_connection(pout[0], pin[1]); | |
8efc0c15 | 136 | |
5260325f | 137 | return 1; |
138 | } | |
8efc0c15 | 139 | |
5260325f | 140 | /* |
141 | * Creates a (possibly privileged) socket for use as the ssh connection. | |
142 | */ | |
143 | int | |
48e671d5 | 144 | ssh_create_socket(uid_t original_real_uid, int privileged, int family) |
8efc0c15 | 145 | { |
5260325f | 146 | int sock; |
147 | ||
aa3378df | 148 | /* |
149 | * If we are running as root and want to connect to a privileged | |
150 | * port, bind our own socket to a privileged port. | |
151 | */ | |
5260325f | 152 | if (privileged) { |
153 | int p = IPPORT_RESERVED - 1; | |
48e671d5 | 154 | sock = rresvport_af(&p, family); |
5260325f | 155 | if (sock < 0) |
48e671d5 | 156 | fatal("rresvport: af=%d %.100s", family, strerror(errno)); |
5260325f | 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); |
48e671d5 | 164 | sock = socket(family, SOCK_STREAM, 0); |
5260325f | 165 | if (sock < 0) |
48e671d5 | 166 | error("socket: %.100s", strerror(errno)); |
5260325f | 167 | restore_uid(); |
168 | } | |
169 | return sock; | |
8efc0c15 | 170 | } |
171 | ||
5260325f | 172 | /* |
48e671d5 | 173 | * Opens a TCP/IP connection to the remote server on the given host. |
174 | * The address of the remote host will be returned in hostaddr. | |
175 | * If port is 0, the default port will be used. If anonymous is zero, | |
5260325f | 176 | * a privileged port will be allocated to make the connection. |
177 | * This requires super-user privileges if anonymous is false. | |
178 | * Connection_attempts specifies the maximum number of tries (one per | |
179 | * second). If proxy_command is non-NULL, it specifies the command (with %h | |
180 | * and %p substituted for host and port, respectively) to use to contact | |
181 | * the daemon. | |
182 | */ | |
183 | int | |
48e671d5 | 184 | ssh_connect(const char *host, struct sockaddr_storage * hostaddr, |
57112b5a | 185 | u_short port, int connection_attempts, |
5260325f | 186 | int anonymous, uid_t original_real_uid, |
187 | const char *proxy_command) | |
8efc0c15 | 188 | { |
48e671d5 | 189 | int sock = -1, attempt; |
5260325f | 190 | struct servent *sp; |
48e671d5 | 191 | struct addrinfo hints, *ai, *aitop; |
192 | char ntop[NI_MAXHOST], strport[NI_MAXSERV]; | |
193 | int gaierr; | |
5260325f | 194 | struct linger linger; |
195 | ||
196 | debug("ssh_connect: getuid %d geteuid %d anon %d", | |
197 | (int) getuid(), (int) geteuid(), anonymous); | |
198 | ||
199 | /* Get default port if port has not been set. */ | |
200 | if (port == 0) { | |
201 | sp = getservbyname(SSH_SERVICE_NAME, "tcp"); | |
202 | if (sp) | |
203 | port = ntohs(sp->s_port); | |
204 | else | |
205 | port = SSH_DEFAULT_PORT; | |
8efc0c15 | 206 | } |
5260325f | 207 | /* If a proxy command is given, connect using it. */ |
208 | if (proxy_command != NULL) | |
209 | return ssh_proxy_connect(host, port, original_real_uid, proxy_command); | |
210 | ||
211 | /* No proxy command. */ | |
212 | ||
48e671d5 | 213 | memset(&hints, 0, sizeof(hints)); |
214 | hints.ai_family = IPv4or6; | |
215 | hints.ai_socktype = SOCK_STREAM; | |
216 | snprintf(strport, sizeof strport, "%d", port); | |
217 | if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) | |
218 | fatal("%s: %.100s: %s", __progname, host, | |
219 | gai_strerror(gaierr)); | |
5260325f | 220 | |
95f1eccc | 221 | /* |
222 | * Try to connect several times. On some machines, the first time | |
223 | * will sometimes fail. In general socket code appears to behave | |
224 | * quite magically on many machines. | |
225 | */ | |
5260325f | 226 | for (attempt = 0; attempt < connection_attempts; attempt++) { |
227 | if (attempt > 0) | |
228 | debug("Trying again..."); | |
229 | ||
48e671d5 | 230 | /* Loop through addresses for this host, and try each one in |
231 | sequence until the connection succeeds. */ | |
232 | for (ai = aitop; ai; ai = ai->ai_next) { | |
233 | if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) | |
234 | continue; | |
235 | if (getnameinfo(ai->ai_addr, ai->ai_addrlen, | |
236 | ntop, sizeof(ntop), strport, sizeof(strport), | |
237 | NI_NUMERICHOST|NI_NUMERICSERV) != 0) { | |
238 | error("ssh_connect: getnameinfo failed"); | |
239 | continue; | |
240 | } | |
241 | debug("Connecting to %.200s [%.100s] port %s.", | |
242 | host, ntop, strport); | |
243 | ||
244 | /* Create a socket for connecting. */ | |
245 | sock = ssh_create_socket(original_real_uid, | |
246 | !anonymous && geteuid() == 0 && port < IPPORT_RESERVED, | |
247 | ai->ai_family); | |
248 | if (sock < 0) | |
249 | continue; | |
250 | ||
251 | /* Connect to the host. We use the user's uid in the | |
252 | * hope that it will help with tcp_wrappers showing | |
253 | * the remote uid as root. | |
aa3378df | 254 | */ |
5260325f | 255 | temporarily_use_uid(original_real_uid); |
48e671d5 | 256 | if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { |
257 | /* Successful connection. */ | |
258 | memcpy(hostaddr, ai->ai_addr, sizeof(*(ai->ai_addr))); | |
5260325f | 259 | restore_uid(); |
260 | break; | |
48e671d5 | 261 | } else { |
5260325f | 262 | debug("connect: %.100s", strerror(errno)); |
263 | restore_uid(); | |
aa3378df | 264 | /* |
265 | * Close the failed socket; there appear to | |
266 | * be some problems when reusing a socket for | |
267 | * which connect() has already returned an | |
268 | * error. | |
269 | */ | |
5260325f | 270 | shutdown(sock, SHUT_RDWR); |
271 | close(sock); | |
272 | } | |
8efc0c15 | 273 | } |
48e671d5 | 274 | if (ai) |
275 | break; /* Successful connection. */ | |
8efc0c15 | 276 | |
5260325f | 277 | /* Sleep a moment before retrying. */ |
278 | sleep(1); | |
279 | } | |
48e671d5 | 280 | |
281 | freeaddrinfo(aitop); | |
282 | ||
5260325f | 283 | /* Return failure if we didn't get a successful connection. */ |
284 | if (attempt >= connection_attempts) | |
285 | return 0; | |
8efc0c15 | 286 | |
5260325f | 287 | debug("Connection established."); |
8efc0c15 | 288 | |
aa3378df | 289 | /* |
290 | * Set socket options. We would like the socket to disappear as soon | |
291 | * as it has been closed for whatever reason. | |
292 | */ | |
293 | /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ | |
5260325f | 294 | linger.l_onoff = 1; |
295 | linger.l_linger = 5; | |
296 | setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger)); | |
8efc0c15 | 297 | |
5260325f | 298 | /* Set the connection. */ |
299 | packet_set_connection(sock, sock); | |
8efc0c15 | 300 | |
5260325f | 301 | return 1; |
8efc0c15 | 302 | } |
303 | ||
5260325f | 304 | /* |
305 | * Checks if the user has an authentication agent, and if so, tries to | |
306 | * authenticate using the agent. | |
307 | */ | |
8efc0c15 | 308 | int |
309 | try_agent_authentication() | |
310 | { | |
5260325f | 311 | int status, type; |
312 | char *comment; | |
313 | AuthenticationConnection *auth; | |
314 | unsigned char response[16]; | |
315 | unsigned int i; | |
316 | BIGNUM *e, *n, *challenge; | |
317 | ||
318 | /* Get connection to the agent. */ | |
319 | auth = ssh_get_authentication_connection(); | |
320 | if (!auth) | |
321 | return 0; | |
322 | ||
323 | e = BN_new(); | |
324 | n = BN_new(); | |
325 | challenge = BN_new(); | |
326 | ||
327 | /* Loop through identities served by the agent. */ | |
328 | for (status = ssh_get_first_identity(auth, e, n, &comment); | |
329 | status; | |
330 | status = ssh_get_next_identity(auth, e, n, &comment)) { | |
331 | int plen, clen; | |
332 | ||
333 | /* Try this identity. */ | |
334 | debug("Trying RSA authentication via agent with '%.100s'", comment); | |
335 | xfree(comment); | |
336 | ||
337 | /* Tell the server that we are willing to authenticate using this key. */ | |
338 | packet_start(SSH_CMSG_AUTH_RSA); | |
339 | packet_put_bignum(n); | |
340 | packet_send(); | |
341 | packet_write_wait(); | |
342 | ||
343 | /* Wait for server's response. */ | |
344 | type = packet_read(&plen); | |
345 | ||
346 | /* The server sends failure if it doesn\'t like our key or | |
347 | does not support RSA authentication. */ | |
348 | if (type == SSH_SMSG_FAILURE) { | |
349 | debug("Server refused our key."); | |
350 | continue; | |
351 | } | |
352 | /* Otherwise it should have sent a challenge. */ | |
353 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
354 | packet_disconnect("Protocol error during RSA authentication: %d", | |
355 | type); | |
8efc0c15 | 356 | |
5260325f | 357 | packet_get_bignum(challenge, &clen); |
8efc0c15 | 358 | |
5260325f | 359 | packet_integrity_check(plen, clen, type); |
8efc0c15 | 360 | |
5260325f | 361 | debug("Received RSA challenge from server."); |
362 | ||
363 | /* Ask the agent to decrypt the challenge. */ | |
364 | if (!ssh_decrypt_challenge(auth, e, n, challenge, | |
365 | session_id, 1, response)) { | |
366 | /* The agent failed to authenticate this identifier although it | |
367 | advertised it supports this. Just return a wrong value. */ | |
368 | log("Authentication agent failed to decrypt challenge."); | |
369 | memset(response, 0, sizeof(response)); | |
370 | } | |
371 | debug("Sending response to RSA challenge."); | |
372 | ||
373 | /* Send the decrypted challenge back to the server. */ | |
374 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
375 | for (i = 0; i < 16; i++) | |
376 | packet_put_char(response[i]); | |
377 | packet_send(); | |
378 | packet_write_wait(); | |
379 | ||
380 | /* Wait for response from the server. */ | |
381 | type = packet_read(&plen); | |
382 | ||
383 | /* The server returns success if it accepted the authentication. */ | |
384 | if (type == SSH_SMSG_SUCCESS) { | |
385 | debug("RSA authentication accepted by server."); | |
386 | BN_clear_free(e); | |
387 | BN_clear_free(n); | |
388 | BN_clear_free(challenge); | |
389 | return 1; | |
390 | } | |
391 | /* Otherwise it should return failure. */ | |
392 | if (type != SSH_SMSG_FAILURE) | |
393 | packet_disconnect("Protocol error waiting RSA auth response: %d", | |
394 | type); | |
395 | } | |
396 | ||
397 | BN_clear_free(e); | |
398 | BN_clear_free(n); | |
399 | BN_clear_free(challenge); | |
8efc0c15 | 400 | |
5260325f | 401 | debug("RSA authentication using agent refused."); |
402 | return 0; | |
403 | } | |
8efc0c15 | 404 | |
5260325f | 405 | /* |
406 | * Computes the proper response to a RSA challenge, and sends the response to | |
407 | * the server. | |
408 | */ | |
8efc0c15 | 409 | void |
5260325f | 410 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
8efc0c15 | 411 | { |
5260325f | 412 | unsigned char buf[32], response[16]; |
413 | MD5_CTX md; | |
414 | int i, len; | |
415 | ||
416 | /* Decrypt the challenge using the private key. */ | |
417 | rsa_private_decrypt(challenge, challenge, prv); | |
418 | ||
419 | /* Compute the response. */ | |
420 | /* The response is MD5 of decrypted challenge plus session id. */ | |
421 | len = BN_num_bytes(challenge); | |
422 | if (len <= 0 || len > sizeof(buf)) | |
423 | packet_disconnect("respond_to_rsa_challenge: bad challenge length %d", | |
424 | len); | |
425 | ||
426 | memset(buf, 0, sizeof(buf)); | |
427 | BN_bn2bin(challenge, buf + sizeof(buf) - len); | |
428 | MD5_Init(&md); | |
429 | MD5_Update(&md, buf, 32); | |
430 | MD5_Update(&md, session_id, 16); | |
431 | MD5_Final(response, &md); | |
432 | ||
433 | debug("Sending response to host key RSA challenge."); | |
434 | ||
435 | /* Send the response back to the server. */ | |
436 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
437 | for (i = 0; i < 16; i++) | |
438 | packet_put_char(response[i]); | |
439 | packet_send(); | |
440 | packet_write_wait(); | |
8efc0c15 | 441 | |
5260325f | 442 | memset(buf, 0, sizeof(buf)); |
443 | memset(response, 0, sizeof(response)); | |
444 | memset(&md, 0, sizeof(md)); | |
445 | } | |
8efc0c15 | 446 | |
5260325f | 447 | /* |
448 | * Checks if the user has authentication file, and if so, tries to authenticate | |
449 | * the user using it. | |
450 | */ | |
8efc0c15 | 451 | int |
57112b5a | 452 | try_rsa_authentication(const char *authfile) |
8efc0c15 | 453 | { |
5260325f | 454 | BIGNUM *challenge; |
455 | RSA *private_key; | |
456 | RSA *public_key; | |
457 | char *passphrase, *comment; | |
458 | int type, i; | |
459 | int plen, clen; | |
460 | ||
461 | /* Try to load identification for the authentication key. */ | |
462 | public_key = RSA_new(); | |
463 | if (!load_public_key(authfile, public_key, &comment)) { | |
464 | RSA_free(public_key); | |
57112b5a | 465 | /* Could not load it. Fail. */ |
466 | return 0; | |
8efc0c15 | 467 | } |
5260325f | 468 | debug("Trying RSA authentication with key '%.100s'", comment); |
469 | ||
470 | /* Tell the server that we are willing to authenticate using this key. */ | |
471 | packet_start(SSH_CMSG_AUTH_RSA); | |
472 | packet_put_bignum(public_key->n); | |
473 | packet_send(); | |
474 | packet_write_wait(); | |
475 | ||
476 | /* We no longer need the public key. */ | |
477 | RSA_free(public_key); | |
478 | ||
479 | /* Wait for server's response. */ | |
480 | type = packet_read(&plen); | |
481 | ||
aa3378df | 482 | /* |
483 | * The server responds with failure if it doesn\'t like our key or | |
484 | * doesn\'t support RSA authentication. | |
485 | */ | |
5260325f | 486 | if (type == SSH_SMSG_FAILURE) { |
487 | debug("Server refused our key."); | |
488 | xfree(comment); | |
57112b5a | 489 | return 0; |
8efc0c15 | 490 | } |
5260325f | 491 | /* Otherwise, the server should respond with a challenge. */ |
492 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
493 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
494 | ||
495 | /* Get the challenge from the packet. */ | |
496 | challenge = BN_new(); | |
497 | packet_get_bignum(challenge, &clen); | |
498 | ||
499 | packet_integrity_check(plen, clen, type); | |
500 | ||
501 | debug("Received RSA challenge from server."); | |
502 | ||
503 | private_key = RSA_new(); | |
aa3378df | 504 | /* |
505 | * Load the private key. Try first with empty passphrase; if it | |
506 | * fails, ask for a passphrase. | |
507 | */ | |
5260325f | 508 | if (!load_private_key(authfile, "", private_key, NULL)) { |
509 | char buf[300]; | |
510 | snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ", | |
a408af76 | 511 | comment); |
5260325f | 512 | if (!options.batch_mode) |
513 | passphrase = read_passphrase(buf, 0); | |
514 | else { | |
515 | debug("Will not query passphrase for %.100s in batch mode.", | |
516 | comment); | |
517 | passphrase = xstrdup(""); | |
518 | } | |
8efc0c15 | 519 | |
5260325f | 520 | /* Load the authentication file using the pasphrase. */ |
521 | if (!load_private_key(authfile, passphrase, private_key, NULL)) { | |
522 | memset(passphrase, 0, strlen(passphrase)); | |
523 | xfree(passphrase); | |
524 | error("Bad passphrase."); | |
525 | ||
526 | /* Send a dummy response packet to avoid protocol error. */ | |
527 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
528 | for (i = 0; i < 16; i++) | |
529 | packet_put_char(0); | |
530 | packet_send(); | |
531 | packet_write_wait(); | |
532 | ||
533 | /* Expect the server to reject it... */ | |
534 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
535 | xfree(comment); | |
536 | return 0; | |
537 | } | |
538 | /* Destroy the passphrase. */ | |
539 | memset(passphrase, 0, strlen(passphrase)); | |
540 | xfree(passphrase); | |
541 | } | |
542 | /* We no longer need the comment. */ | |
543 | xfree(comment); | |
544 | ||
545 | /* Compute and send a response to the challenge. */ | |
546 | respond_to_rsa_challenge(challenge, private_key); | |
547 | ||
548 | /* Destroy the private key. */ | |
549 | RSA_free(private_key); | |
8efc0c15 | 550 | |
5260325f | 551 | /* We no longer need the challenge. */ |
552 | BN_clear_free(challenge); | |
553 | ||
554 | /* Wait for response from the server. */ | |
555 | type = packet_read(&plen); | |
556 | if (type == SSH_SMSG_SUCCESS) { | |
557 | debug("RSA authentication accepted by server."); | |
558 | return 1; | |
559 | } | |
560 | if (type != SSH_SMSG_FAILURE) | |
561 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
562 | debug("RSA authentication refused."); | |
563 | return 0; | |
564 | } | |
8efc0c15 | 565 | |
5260325f | 566 | /* |
567 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
568 | * authentication and RSA host authentication. | |
569 | */ | |
8efc0c15 | 570 | int |
5260325f | 571 | try_rhosts_rsa_authentication(const char *local_user, RSA * host_key) |
8efc0c15 | 572 | { |
5260325f | 573 | int type; |
574 | BIGNUM *challenge; | |
575 | int plen, clen; | |
576 | ||
577 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
578 | ||
579 | /* Tell the server that we are willing to authenticate using this key. */ | |
580 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
581 | packet_put_string(local_user, strlen(local_user)); | |
582 | packet_put_int(BN_num_bits(host_key->n)); | |
583 | packet_put_bignum(host_key->e); | |
584 | packet_put_bignum(host_key->n); | |
585 | packet_send(); | |
586 | packet_write_wait(); | |
587 | ||
588 | /* Wait for server's response. */ | |
589 | type = packet_read(&plen); | |
590 | ||
591 | /* The server responds with failure if it doesn't admit our | |
592 | .rhosts authentication or doesn't know our host key. */ | |
593 | if (type == SSH_SMSG_FAILURE) { | |
594 | debug("Server refused our rhosts authentication or host key."); | |
595 | return 0; | |
596 | } | |
597 | /* Otherwise, the server should respond with a challenge. */ | |
598 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
599 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
600 | ||
601 | /* Get the challenge from the packet. */ | |
602 | challenge = BN_new(); | |
603 | packet_get_bignum(challenge, &clen); | |
604 | ||
605 | packet_integrity_check(plen, clen, type); | |
606 | ||
607 | debug("Received RSA challenge for host key from server."); | |
608 | ||
609 | /* Compute a response to the challenge. */ | |
610 | respond_to_rsa_challenge(challenge, host_key); | |
611 | ||
612 | /* We no longer need the challenge. */ | |
613 | BN_clear_free(challenge); | |
614 | ||
615 | /* Wait for response from the server. */ | |
616 | type = packet_read(&plen); | |
617 | if (type == SSH_SMSG_SUCCESS) { | |
618 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
619 | return 1; | |
620 | } | |
621 | if (type != SSH_SMSG_FAILURE) | |
622 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
623 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
624 | return 0; | |
8efc0c15 | 625 | } |
626 | ||
627 | #ifdef KRB4 | |
5260325f | 628 | int |
629 | try_kerberos_authentication() | |
8efc0c15 | 630 | { |
5260325f | 631 | KTEXT_ST auth; /* Kerberos data */ |
632 | char *reply; | |
633 | char inst[INST_SZ]; | |
634 | char *realm; | |
635 | CREDENTIALS cred; | |
636 | int r, type, plen; | |
637 | Key_schedule schedule; | |
638 | u_long checksum, cksum; | |
639 | MSG_DAT msg_data; | |
640 | struct sockaddr_in local, foreign; | |
641 | struct stat st; | |
642 | ||
643 | /* Don't do anything if we don't have any tickets. */ | |
644 | if (stat(tkt_string(), &st) < 0) | |
645 | return 0; | |
646 | ||
647 | strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ); | |
648 | ||
649 | realm = (char *) krb_realmofhost(get_canonical_hostname()); | |
650 | if (!realm) { | |
651 | debug("Kerberos V4: no realm for %s", get_canonical_hostname()); | |
652 | return 0; | |
653 | } | |
654 | /* This can really be anything. */ | |
655 | checksum = (u_long) getpid(); | |
656 | ||
657 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); | |
658 | if (r != KSUCCESS) { | |
659 | debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]); | |
660 | return 0; | |
661 | } | |
662 | /* Get session key to decrypt the server's reply with. */ | |
663 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
664 | if (r != KSUCCESS) { | |
665 | debug("get_cred failed: %s", krb_err_txt[r]); | |
666 | return 0; | |
667 | } | |
668 | des_key_sched((des_cblock *) cred.session, schedule); | |
669 | ||
670 | /* Send authentication info to server. */ | |
671 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
672 | packet_put_string((char *) auth.dat, auth.length); | |
673 | packet_send(); | |
674 | packet_write_wait(); | |
675 | ||
676 | /* Zero the buffer. */ | |
677 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
678 | ||
679 | r = sizeof(local); | |
680 | memset(&local, 0, sizeof(local)); | |
681 | if (getsockname(packet_get_connection_in(), | |
682 | (struct sockaddr *) & local, &r) < 0) | |
683 | debug("getsockname failed: %s", strerror(errno)); | |
684 | ||
685 | r = sizeof(foreign); | |
686 | memset(&foreign, 0, sizeof(foreign)); | |
687 | if (getpeername(packet_get_connection_in(), | |
688 | (struct sockaddr *) & foreign, &r) < 0) { | |
689 | debug("getpeername failed: %s", strerror(errno)); | |
690 | fatal_cleanup(); | |
691 | } | |
692 | /* Get server reply. */ | |
693 | type = packet_read(&plen); | |
694 | switch (type) { | |
695 | case SSH_SMSG_FAILURE: | |
696 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
697 | debug("Kerberos V4 authentication failed."); | |
698 | return 0; | |
699 | break; | |
700 | ||
701 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
702 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
703 | debug("Kerberos V4 authentication accepted."); | |
704 | ||
705 | /* Get server's response. */ | |
706 | reply = packet_get_string((unsigned int *) &auth.length); | |
707 | memcpy(auth.dat, reply, auth.length); | |
708 | xfree(reply); | |
709 | ||
710 | packet_integrity_check(plen, 4 + auth.length, type); | |
711 | ||
aa3378df | 712 | /* |
713 | * If his response isn't properly encrypted with the session | |
714 | * key, and the decrypted checksum fails to match, he's | |
715 | * bogus. Bail out. | |
716 | */ | |
5260325f | 717 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, |
718 | &foreign, &local, &msg_data); | |
719 | if (r != KSUCCESS) { | |
720 | debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]); | |
721 | packet_disconnect("Kerberos V4 challenge failed!"); | |
722 | } | |
723 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
724 | (void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum)); | |
725 | cksum = ntohl(cksum); | |
726 | ||
727 | /* If it matches, we're golden. */ | |
728 | if (cksum == checksum + 1) { | |
729 | debug("Kerberos V4 challenge successful."); | |
730 | return 1; | |
731 | } else | |
732 | packet_disconnect("Kerberos V4 challenge failed!"); | |
733 | break; | |
734 | ||
735 | default: | |
736 | packet_disconnect("Protocol error on Kerberos V4 response: %d", type); | |
737 | } | |
738 | return 0; | |
8efc0c15 | 739 | } |
5260325f | 740 | |
8efc0c15 | 741 | #endif /* KRB4 */ |
742 | ||
743 | #ifdef AFS | |
5260325f | 744 | int |
745 | send_kerberos_tgt() | |
8efc0c15 | 746 | { |
5260325f | 747 | CREDENTIALS *creds; |
748 | char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; | |
749 | int r, type, plen; | |
750 | unsigned char buffer[8192]; | |
751 | struct stat st; | |
752 | ||
753 | /* Don't do anything if we don't have any tickets. */ | |
754 | if (stat(tkt_string(), &st) < 0) | |
755 | return 0; | |
756 | ||
757 | creds = xmalloc(sizeof(*creds)); | |
758 | ||
759 | if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) { | |
760 | debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]); | |
761 | return 0; | |
762 | } | |
763 | if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) { | |
764 | debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]); | |
765 | return 0; | |
766 | } | |
767 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { | |
768 | debug("Kerberos V4 ticket expired: %s", TKT_FILE); | |
769 | return 0; | |
770 | } | |
771 | creds_to_radix(creds, buffer); | |
772 | xfree(creds); | |
773 | ||
774 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
775 | packet_put_string((char *) buffer, strlen(buffer)); | |
776 | packet_send(); | |
777 | packet_write_wait(); | |
778 | ||
779 | type = packet_read(&plen); | |
780 | ||
781 | if (type == SSH_SMSG_FAILURE) | |
782 | debug("Kerberos TGT for realm %s rejected.", prealm); | |
783 | else if (type != SSH_SMSG_SUCCESS) | |
784 | packet_disconnect("Protocol error on Kerberos TGT response: %d", type); | |
785 | ||
786 | return 1; | |
8efc0c15 | 787 | } |
788 | ||
5260325f | 789 | void |
790 | send_afs_tokens(void) | |
8efc0c15 | 791 | { |
5260325f | 792 | CREDENTIALS creds; |
793 | struct ViceIoctl parms; | |
794 | struct ClearToken ct; | |
795 | int i, type, len, plen; | |
796 | char buf[2048], *p, *server_cell; | |
797 | unsigned char buffer[8192]; | |
798 | ||
799 | /* Move over ktc_GetToken, here's something leaner. */ | |
800 | for (i = 0; i < 100; i++) { /* just in case */ | |
801 | parms.in = (char *) &i; | |
802 | parms.in_size = sizeof(i); | |
803 | parms.out = buf; | |
804 | parms.out_size = sizeof(buf); | |
805 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
806 | break; | |
807 | p = buf; | |
808 | ||
809 | /* Get secret token. */ | |
810 | memcpy(&creds.ticket_st.length, p, sizeof(unsigned int)); | |
811 | if (creds.ticket_st.length > MAX_KTXT_LEN) | |
812 | break; | |
813 | p += sizeof(unsigned int); | |
814 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); | |
815 | p += creds.ticket_st.length; | |
816 | ||
817 | /* Get clear token. */ | |
818 | memcpy(&len, p, sizeof(len)); | |
819 | if (len != sizeof(struct ClearToken)) | |
820 | break; | |
821 | p += sizeof(len); | |
822 | memcpy(&ct, p, len); | |
823 | p += len; | |
824 | p += sizeof(len); /* primary flag */ | |
825 | server_cell = p; | |
826 | ||
827 | /* Flesh out our credentials. */ | |
828 | strlcpy(creds.service, "afs", sizeof creds.service); | |
829 | creds.instance[0] = '\0'; | |
830 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
831 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
832 | creds.issue_date = ct.BeginTimestamp; | |
833 | creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp); | |
834 | creds.kvno = ct.AuthHandle; | |
835 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
836 | creds.pinst[0] = '\0'; | |
837 | ||
838 | /* Encode token, ship it off. */ | |
839 | if (!creds_to_radix(&creds, buffer)) | |
840 | break; | |
841 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
842 | packet_put_string((char *) buffer, strlen(buffer)); | |
843 | packet_send(); | |
844 | packet_write_wait(); | |
845 | ||
846 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
847 | Victor? */ | |
848 | type = packet_read(&plen); | |
849 | ||
850 | if (type == SSH_SMSG_FAILURE) | |
851 | debug("AFS token for cell %s rejected.", server_cell); | |
852 | else if (type != SSH_SMSG_SUCCESS) | |
853 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
854 | } | |
8efc0c15 | 855 | } |
8efc0c15 | 856 | |
5260325f | 857 | #endif /* AFS */ |
8efc0c15 | 858 | |
57112b5a | 859 | /* |
860 | * Tries to authenticate with any string-based challenge/response system. | |
861 | * Note that the client code is not tied to s/key or TIS. | |
862 | */ | |
863 | int | |
864 | try_skey_authentication() | |
865 | { | |
866 | int type, i, payload_len; | |
867 | char *challenge, *response; | |
868 | ||
869 | debug("Doing skey authentication."); | |
870 | ||
871 | /* request a challenge */ | |
872 | packet_start(SSH_CMSG_AUTH_TIS); | |
873 | packet_send(); | |
874 | packet_write_wait(); | |
875 | ||
876 | type = packet_read(&payload_len); | |
877 | if (type != SSH_SMSG_FAILURE && | |
878 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
879 | packet_disconnect("Protocol error: got %d in response " | |
880 | "to skey-auth", type); | |
881 | } | |
882 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
883 | debug("No challenge for skey authentication."); | |
884 | return 0; | |
885 | } | |
886 | challenge = packet_get_string(&payload_len); | |
887 | if (options.cipher == SSH_CIPHER_NONE) | |
888 | log("WARNING: Encryption is disabled! " | |
889 | "Reponse will be transmitted in clear text."); | |
890 | fprintf(stderr, "%s\n", challenge); | |
891 | fflush(stderr); | |
892 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
893 | if (i != 0) | |
894 | error("Permission denied, please try again."); | |
895 | response = read_passphrase("Response: ", 0); | |
896 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); | |
897 | packet_put_string(response, strlen(response)); | |
898 | memset(response, 0, strlen(response)); | |
899 | xfree(response); | |
900 | packet_send(); | |
901 | packet_write_wait(); | |
902 | type = packet_read(&payload_len); | |
903 | if (type == SSH_SMSG_SUCCESS) | |
904 | return 1; | |
905 | if (type != SSH_SMSG_FAILURE) | |
906 | packet_disconnect("Protocol error: got %d in response " | |
907 | "to skey-auth-reponse", type); | |
908 | } | |
909 | /* failure */ | |
910 | return 0; | |
911 | } | |
912 | ||
913 | /* | |
914 | * Tries to authenticate with plain passwd authentication. | |
915 | */ | |
916 | int | |
917 | try_password_authentication(char *prompt) | |
918 | { | |
919 | int type, i, payload_len; | |
920 | char *password; | |
921 | ||
922 | debug("Doing password authentication."); | |
923 | if (options.cipher == SSH_CIPHER_NONE) | |
924 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
925 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
926 | if (i != 0) | |
927 | error("Permission denied, please try again."); | |
928 | password = read_passphrase(prompt, 0); | |
929 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
930 | packet_put_string(password, strlen(password)); | |
931 | memset(password, 0, strlen(password)); | |
932 | xfree(password); | |
933 | packet_send(); | |
934 | packet_write_wait(); | |
935 | ||
936 | type = packet_read(&payload_len); | |
937 | if (type == SSH_SMSG_SUCCESS) | |
938 | return 1; | |
939 | if (type != SSH_SMSG_FAILURE) | |
940 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
941 | } | |
942 | /* failure */ | |
943 | return 0; | |
944 | } | |
945 | ||
5260325f | 946 | /* |
947 | * Waits for the server identification string, and sends our own | |
948 | * identification string. | |
949 | */ | |
950 | void | |
951 | ssh_exchange_identification() | |
8efc0c15 | 952 | { |
5260325f | 953 | char buf[256], remote_version[256]; /* must be same size! */ |
954 | int remote_major, remote_minor, i; | |
955 | int connection_in = packet_get_connection_in(); | |
956 | int connection_out = packet_get_connection_out(); | |
5260325f | 957 | |
958 | /* Read other side\'s version identification. */ | |
959 | for (i = 0; i < sizeof(buf) - 1; i++) { | |
960 | if (read(connection_in, &buf[i], 1) != 1) | |
961 | fatal("ssh_exchange_identification: read: %.100s", strerror(errno)); | |
962 | if (buf[i] == '\r') { | |
963 | buf[i] = '\n'; | |
964 | buf[i + 1] = 0; | |
965 | break; | |
966 | } | |
967 | if (buf[i] == '\n') { | |
968 | buf[i + 1] = 0; | |
969 | break; | |
970 | } | |
8efc0c15 | 971 | } |
5260325f | 972 | buf[sizeof(buf) - 1] = 0; |
973 | ||
aa3378df | 974 | /* |
975 | * Check that the versions match. In future this might accept | |
976 | * several versions and set appropriate flags to handle them. | |
977 | */ | |
5260325f | 978 | if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, |
979 | remote_version) != 3) | |
980 | fatal("Bad remote protocol version identification: '%.100s'", buf); | |
981 | debug("Remote protocol version %d.%d, remote software version %.100s", | |
982 | remote_major, remote_minor, remote_version); | |
983 | ||
984 | /* Check if the remote protocol version is too old. */ | |
985 | if (remote_major == 1 && remote_minor < 3) | |
986 | fatal("Remote machine has too old SSH software version."); | |
987 | ||
988 | /* We speak 1.3, too. */ | |
989 | if (remote_major == 1 && remote_minor == 3) { | |
990 | enable_compat13(); | |
e02735bb | 991 | if (options.forward_agent && strcmp(remote_version, "OpenSSH-1.1") != 0) { |
5260325f | 992 | log("Agent forwarding disabled, remote version '%s' is not compatible.", |
993 | remote_version); | |
994 | options.forward_agent = 0; | |
995 | } | |
8efc0c15 | 996 | } |
8efc0c15 | 997 | #if 0 |
aa3378df | 998 | /* |
999 | * Removed for now, to permit compatibility with latter versions. The | |
1000 | * server will reject our version and disconnect if it doesn't | |
1001 | * support it. | |
1002 | */ | |
5260325f | 1003 | if (remote_major != PROTOCOL_MAJOR) |
1004 | fatal("Protocol major versions differ: %d vs. %d", | |
1005 | PROTOCOL_MAJOR, remote_major); | |
8efc0c15 | 1006 | #endif |
1007 | ||
5260325f | 1008 | /* Send our own protocol version identification. */ |
1009 | snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", | |
a408af76 | 1010 | PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); |
1011 | if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf)) | |
5260325f | 1012 | fatal("write: %.100s", strerror(errno)); |
8efc0c15 | 1013 | } |
1014 | ||
1015 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
1016 | ||
5260325f | 1017 | int |
1018 | read_yes_or_no(const char *prompt, int defval) | |
8efc0c15 | 1019 | { |
5260325f | 1020 | char buf[1024]; |
1021 | FILE *f; | |
1022 | int retval = -1; | |
1023 | ||
1024 | if (isatty(0)) | |
1025 | f = stdin; | |
1026 | else | |
1027 | f = fopen("/dev/tty", "rw"); | |
1028 | ||
1029 | if (f == NULL) | |
1030 | return 0; | |
1031 | ||
1032 | fflush(stdout); | |
1033 | ||
1034 | while (1) { | |
1035 | fprintf(stderr, "%s", prompt); | |
1036 | if (fgets(buf, sizeof(buf), f) == NULL) { | |
1037 | /* Print a newline (the prompt probably didn\'t have one). */ | |
1038 | fprintf(stderr, "\n"); | |
1039 | strlcpy(buf, "no", sizeof buf); | |
1040 | } | |
1041 | /* Remove newline from response. */ | |
1042 | if (strchr(buf, '\n')) | |
1043 | *strchr(buf, '\n') = 0; | |
1044 | ||
1045 | if (buf[0] == 0) | |
1046 | retval = defval; | |
1047 | if (strcmp(buf, "yes") == 0) | |
1048 | retval = 1; | |
1049 | if (strcmp(buf, "no") == 0) | |
1050 | retval = 0; | |
1051 | ||
1052 | if (retval != -1) { | |
1053 | if (f != stdin) | |
1054 | fclose(f); | |
1055 | return retval; | |
1056 | } | |
8efc0c15 | 1057 | } |
8efc0c15 | 1058 | } |
1059 | ||
5260325f | 1060 | /* |
95f1eccc | 1061 | * check whether the supplied host key is valid, return only if ok. |
5260325f | 1062 | */ |
95f1eccc | 1063 | |
5260325f | 1064 | void |
48e671d5 | 1065 | check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key) |
8efc0c15 | 1066 | { |
95f1eccc | 1067 | RSA *file_key; |
1068 | char *ip = NULL; | |
5260325f | 1069 | char hostline[1000], *hostp; |
5260325f | 1070 | HostStatus host_status; |
1071 | HostStatus ip_status; | |
48e671d5 | 1072 | int local = 0, host_ip_differ = 0; |
1073 | int sa_len; | |
1074 | char ntop[NI_MAXHOST]; | |
1075 | ||
1076 | /* | |
1077 | * Force accepting of the host key for loopback/localhost. The | |
1078 | * problem is that if the home directory is NFS-mounted to multiple | |
1079 | * machines, localhost will refer to a different machine in each of | |
1080 | * them, and the user will get bogus HOST_CHANGED warnings. This | |
1081 | * essentially disables host authentication for localhost; however, | |
1082 | * this is probably not a real problem. | |
1083 | */ | |
1084 | switch (hostaddr->sa_family) { | |
1085 | case AF_INET: | |
1086 | local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET; | |
1087 | sa_len = sizeof(struct sockaddr_in); | |
1088 | break; | |
1089 | case AF_INET6: | |
1090 | local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr)); | |
1091 | sa_len = sizeof(struct sockaddr_in6); | |
1092 | break; | |
1093 | default: | |
1094 | local = 0; | |
1095 | sa_len = sizeof(struct sockaddr_storage); | |
1096 | break; | |
1097 | } | |
1098 | if (local) { | |
1099 | debug("Forcing accepting of host key for loopback/localhost."); | |
1100 | return; | |
1101 | } | |
5260325f | 1102 | |
57112b5a | 1103 | /* |
1104 | * Turn off check_host_ip for proxy connects, since | |
1105 | * we don't have the remote ip-address | |
1106 | */ | |
1107 | if (options.proxy_command != NULL && options.check_host_ip) | |
1108 | options.check_host_ip = 0; | |
1109 | ||
48e671d5 | 1110 | if (options.check_host_ip) { |
1111 | if (getnameinfo(hostaddr, sa_len, ntop, sizeof(ntop), | |
1112 | NULL, 0, NI_NUMERICHOST) != 0) | |
1113 | fatal("check_host_key: getnameinfo failed"); | |
1114 | ip = xstrdup(ntop); | |
1115 | } | |
5260325f | 1116 | |
95f1eccc | 1117 | /* |
1118 | * Store the host key from the known host file in here so that we can | |
1119 | * compare it with the key for the IP address. | |
1120 | */ | |
5260325f | 1121 | file_key = RSA_new(); |
1122 | file_key->n = BN_new(); | |
1123 | file_key->e = BN_new(); | |
1124 | ||
aa3378df | 1125 | /* |
1126 | * Check if the host key is present in the user\'s list of known | |
1127 | * hosts or in the systemwide list. | |
1128 | */ | |
5260325f | 1129 | host_status = check_host_in_hostfile(options.user_hostfile, host, |
1130 | host_key->e, host_key->n, | |
1131 | file_key->e, file_key->n); | |
1132 | if (host_status == HOST_NEW) | |
1133 | host_status = check_host_in_hostfile(options.system_hostfile, host, | |
1134 | host_key->e, host_key->n, | |
1135 | file_key->e, file_key->n); | |
aa3378df | 1136 | /* |
1137 | * Also perform check for the ip address, skip the check if we are | |
1138 | * localhost or the hostname was an ip address to begin with | |
1139 | */ | |
5260325f | 1140 | if (options.check_host_ip && !local && strcmp(host, ip)) { |
1141 | RSA *ip_key = RSA_new(); | |
1142 | ip_key->n = BN_new(); | |
1143 | ip_key->e = BN_new(); | |
1144 | ip_status = check_host_in_hostfile(options.user_hostfile, ip, | |
1145 | host_key->e, host_key->n, | |
1146 | ip_key->e, ip_key->n); | |
1147 | ||
1148 | if (ip_status == HOST_NEW) | |
1149 | ip_status = check_host_in_hostfile(options.system_hostfile, ip, | |
1150 | host_key->e, host_key->n, | |
1151 | ip_key->e, ip_key->n); | |
1152 | if (host_status == HOST_CHANGED && | |
1153 | (ip_status != HOST_CHANGED || | |
1154 | (BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n)))) | |
1155 | host_ip_differ = 1; | |
1156 | ||
1157 | RSA_free(ip_key); | |
1158 | } else | |
1159 | ip_status = host_status; | |
1160 | ||
1161 | RSA_free(file_key); | |
1162 | ||
1163 | switch (host_status) { | |
1164 | case HOST_OK: | |
1165 | /* The host is known and the key matches. */ | |
1166 | debug("Host '%.200s' is known and matches the host key.", host); | |
1167 | if (options.check_host_ip) { | |
1168 | if (ip_status == HOST_NEW) { | |
1169 | if (!add_host_to_hostfile(options.user_hostfile, ip, | |
1170 | host_key->e, host_key->n)) | |
1171 | log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).", | |
1172 | ip, options.user_hostfile); | |
1173 | else | |
1174 | log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.", | |
1175 | ip); | |
1176 | } else if (ip_status != HOST_OK) | |
1177 | log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'", | |
1178 | host, ip); | |
1179 | } | |
1180 | break; | |
1181 | case HOST_NEW: | |
1182 | /* The host is new. */ | |
1183 | if (options.strict_host_key_checking == 1) { | |
1184 | /* User has requested strict host key checking. We will not add the host key | |
1185 | automatically. The only alternative left is to abort. */ | |
1186 | fatal("No host key is known for %.200s and you have requested strict checking.", host); | |
1187 | } else if (options.strict_host_key_checking == 2) { | |
1188 | /* The default */ | |
1189 | char prompt[1024]; | |
1190 | char *fp = fingerprint(host_key->e, host_key->n); | |
1191 | snprintf(prompt, sizeof(prompt), | |
a408af76 | 1192 | "The authenticity of host '%.200s' can't be established.\n" |
1193 | "Key fingerprint is %d %s.\n" | |
1194 | "Are you sure you want to continue connecting (yes/no)? ", | |
1195 | host, BN_num_bits(host_key->n), fp); | |
5260325f | 1196 | if (!read_yes_or_no(prompt, -1)) |
1197 | fatal("Aborted by user!\n"); | |
1198 | } | |
1199 | if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) { | |
1200 | snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); | |
1201 | hostp = hostline; | |
1202 | } else | |
1203 | hostp = host; | |
1204 | ||
1205 | /* If not in strict mode, add the key automatically to the local known_hosts file. */ | |
1206 | if (!add_host_to_hostfile(options.user_hostfile, hostp, | |
1207 | host_key->e, host_key->n)) | |
1208 | log("Failed to add the host to the list of known hosts (%.500s).", | |
1209 | options.user_hostfile); | |
1210 | else | |
1211 | log("Warning: Permanently added '%.200s' to the list of known hosts.", | |
1212 | hostp); | |
1213 | break; | |
1214 | case HOST_CHANGED: | |
1215 | if (options.check_host_ip && host_ip_differ) { | |
1216 | char *msg; | |
1217 | if (ip_status == HOST_NEW) | |
1218 | msg = "is unknown"; | |
1219 | else if (ip_status == HOST_OK) | |
1220 | msg = "is unchanged"; | |
1221 | else | |
1222 | msg = "has a different value"; | |
1223 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1224 | error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @"); | |
1225 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
1226 | error("The host key for %s has changed,", host); | |
1227 | error("and the key for the according IP address %s", ip); | |
1228 | error("%s. This could either mean that", msg); | |
1229 | error("DNS SPOOFING is happening or the IP address for the host"); | |
1230 | error("and its host key have changed at the same time"); | |
1231 | } | |
1232 | /* The host key has changed. */ | |
1233 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); | |
ae2f7af7 | 1234 | error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @"); |
5260325f | 1235 | error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
1236 | error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!"); | |
1237 | error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); | |
1238 | error("It is also possible that the host key has just been changed."); | |
1239 | error("Please contact your system administrator."); | |
1240 | error("Add correct host key in %.100s to get rid of this message.", | |
1241 | options.user_hostfile); | |
1242 | ||
aa3378df | 1243 | /* |
1244 | * If strict host key checking is in use, the user will have | |
1245 | * to edit the key manually and we can only abort. | |
1246 | */ | |
5260325f | 1247 | if (options.strict_host_key_checking) |
1248 | fatal("Host key for %.200s has changed and you have requested strict checking.", host); | |
1249 | ||
aa3378df | 1250 | /* |
1251 | * If strict host key checking has not been requested, allow | |
1252 | * the connection but without password authentication or | |
1253 | * agent forwarding. | |
1254 | */ | |
5260325f | 1255 | if (options.password_authentication) { |
1256 | error("Password authentication is disabled to avoid trojan horses."); | |
1257 | options.password_authentication = 0; | |
1258 | } | |
1259 | if (options.forward_agent) { | |
1260 | error("Agent forwarding is disabled to avoid trojan horses."); | |
1261 | options.forward_agent = 0; | |
1262 | } | |
aa3378df | 1263 | /* |
1264 | * XXX Should permit the user to change to use the new id. | |
1265 | * This could be done by converting the host key to an | |
1266 | * identifying sentence, tell that the host identifies itself | |
1267 | * by that sentence, and ask the user if he/she whishes to | |
1268 | * accept the authentication. | |
1269 | */ | |
5260325f | 1270 | break; |
1271 | } | |
5260325f | 1272 | if (options.check_host_ip) |
1273 | xfree(ip); | |
95f1eccc | 1274 | } |
1275 | ||
1276 | /* | |
1277 | * Starts a dialog with the server, and authenticates the current user on the | |
1278 | * server. This does not need any extra privileges. The basic connection | |
1279 | * to the server must already have been established before this is called. | |
1280 | * User is the remote user; if it is NULL, the current local user name will | |
1281 | * be used. Anonymous indicates that no rhosts authentication will be used. | |
1282 | * If login fails, this function prints an error and never returns. | |
1283 | * This function does not require super-user privileges. | |
1284 | */ | |
1285 | void | |
1286 | ssh_login(int host_key_valid, | |
1287 | RSA *own_host_key, | |
1288 | const char *orighost, | |
48e671d5 | 1289 | struct sockaddr *hostaddr, |
95f1eccc | 1290 | uid_t original_real_uid) |
1291 | { | |
1292 | int i, type; | |
1293 | struct passwd *pw; | |
1294 | BIGNUM *key; | |
1295 | RSA *host_key; | |
1296 | RSA *public_key; | |
1297 | int bits, rbits; | |
1298 | unsigned char session_key[SSH_SESSION_KEY_LENGTH]; | |
1299 | const char *server_user, *local_user; | |
1300 | char *host, *cp; | |
1301 | unsigned char check_bytes[8]; | |
1302 | unsigned int supported_ciphers, supported_authentications; | |
1303 | unsigned int server_flags, client_flags; | |
1304 | int payload_len, clen, sum_len = 0; | |
1305 | u_int32_t rand = 0; | |
1306 | ||
1307 | /* Convert the user-supplied hostname into all lowercase. */ | |
1308 | host = xstrdup(orighost); | |
1309 | for (cp = host; *cp; cp++) | |
1310 | if (isupper(*cp)) | |
1311 | *cp = tolower(*cp); | |
1312 | ||
1313 | /* Exchange protocol version identification strings with the server. */ | |
1314 | ssh_exchange_identification(); | |
1315 | ||
1316 | /* Put the connection into non-blocking mode. */ | |
1317 | packet_set_nonblocking(); | |
1318 | ||
1319 | /* Get local user name. Use it as server user if no user name was given. */ | |
1320 | pw = getpwuid(original_real_uid); | |
1321 | if (!pw) | |
1322 | fatal("User id %d not found from user database.", original_real_uid); | |
1323 | local_user = xstrdup(pw->pw_name); | |
1324 | server_user = options.user ? options.user : local_user; | |
1325 | ||
1326 | debug("Waiting for server public key."); | |
1327 | ||
1328 | /* Wait for a public key packet from the server. */ | |
1329 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
1330 | ||
1331 | /* Get check bytes from the packet. */ | |
1332 | for (i = 0; i < 8; i++) | |
1333 | check_bytes[i] = packet_get_char(); | |
1334 | ||
1335 | /* Get the public key. */ | |
1336 | public_key = RSA_new(); | |
1337 | bits = packet_get_int();/* bits */ | |
1338 | public_key->e = BN_new(); | |
1339 | packet_get_bignum(public_key->e, &clen); | |
1340 | sum_len += clen; | |
1341 | public_key->n = BN_new(); | |
1342 | packet_get_bignum(public_key->n, &clen); | |
1343 | sum_len += clen; | |
1344 | ||
1345 | rbits = BN_num_bits(public_key->n); | |
1346 | if (bits != rbits) { | |
1347 | log("Warning: Server lies about size of server public key: " | |
1348 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1349 | log("Warning: This may be due to an old implementation of ssh."); | |
1350 | } | |
1351 | /* Get the host key. */ | |
1352 | host_key = RSA_new(); | |
1353 | bits = packet_get_int();/* bits */ | |
1354 | host_key->e = BN_new(); | |
1355 | packet_get_bignum(host_key->e, &clen); | |
1356 | sum_len += clen; | |
1357 | host_key->n = BN_new(); | |
1358 | packet_get_bignum(host_key->n, &clen); | |
1359 | sum_len += clen; | |
1360 | ||
1361 | rbits = BN_num_bits(host_key->n); | |
1362 | if (bits != rbits) { | |
1363 | log("Warning: Server lies about size of server host key: " | |
1364 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
1365 | log("Warning: This may be due to an old implementation of ssh."); | |
1366 | } | |
1367 | ||
1368 | /* Get protocol flags. */ | |
1369 | server_flags = packet_get_int(); | |
1370 | packet_set_protocol_flags(server_flags); | |
1371 | ||
1372 | supported_ciphers = packet_get_int(); | |
1373 | supported_authentications = packet_get_int(); | |
1374 | ||
1375 | debug("Received server public key (%d bits) and host key (%d bits).", | |
1376 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
1377 | ||
1378 | packet_integrity_check(payload_len, | |
1379 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
1380 | SSH_SMSG_PUBLIC_KEY); | |
1381 | ||
1382 | check_host_key(host, hostaddr, host_key); | |
1383 | ||
1384 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; | |
1385 | ||
1386 | compute_session_id(session_id, check_bytes, host_key->n, public_key->n); | |
5260325f | 1387 | |
1388 | /* Generate a session key. */ | |
1389 | arc4random_stir(); | |
1390 | ||
aa3378df | 1391 | /* |
1392 | * Generate an encryption key for the session. The key is a 256 bit | |
1393 | * random number, interpreted as a 32-byte key, with the least | |
1394 | * significant 8 bits being the first byte of the key. | |
1395 | */ | |
5260325f | 1396 | for (i = 0; i < 32; i++) { |
1397 | if (i % 4 == 0) | |
1398 | rand = arc4random(); | |
1399 | session_key[i] = rand & 0xff; | |
1400 | rand >>= 8; | |
1401 | } | |
1402 | ||
aa3378df | 1403 | /* |
1404 | * According to the protocol spec, the first byte of the session key | |
1405 | * is the highest byte of the integer. The session key is xored with | |
1406 | * the first 16 bytes of the session id. | |
1407 | */ | |
5260325f | 1408 | key = BN_new(); |
1409 | BN_set_word(key, 0); | |
1410 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1411 | BN_lshift(key, key, 8); | |
1412 | if (i < 16) | |
1413 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1414 | else | |
1415 | BN_add_word(key, session_key[i]); | |
1416 | } | |
1417 | ||
aa3378df | 1418 | /* |
1419 | * Encrypt the integer using the public key and host key of the | |
1420 | * server (key with smaller modulus first). | |
1421 | */ | |
5260325f | 1422 | if (BN_cmp(public_key->n, host_key->n) < 0) { |
1423 | /* Public key has smaller modulus. */ | |
1424 | if (BN_num_bits(host_key->n) < | |
1425 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1426 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1427 | "SSH_KEY_BITS_RESERVED %d", | |
1428 | BN_num_bits(host_key->n), | |
1429 | BN_num_bits(public_key->n), | |
1430 | SSH_KEY_BITS_RESERVED); | |
1431 | } | |
1432 | rsa_public_encrypt(key, key, public_key); | |
1433 | rsa_public_encrypt(key, key, host_key); | |
1434 | } else { | |
1435 | /* Host key has smaller modulus (or they are equal). */ | |
1436 | if (BN_num_bits(public_key->n) < | |
1437 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1438 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1439 | "SSH_KEY_BITS_RESERVED %d", | |
1440 | BN_num_bits(public_key->n), | |
1441 | BN_num_bits(host_key->n), | |
1442 | SSH_KEY_BITS_RESERVED); | |
1443 | } | |
1444 | rsa_public_encrypt(key, key, host_key); | |
1445 | rsa_public_encrypt(key, key, public_key); | |
1446 | } | |
1447 | ||
1448 | if (options.cipher == SSH_CIPHER_NOT_SET) { | |
1449 | if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default)) | |
1450 | options.cipher = ssh_cipher_default; | |
1451 | else { | |
1452 | debug("Cipher %s not supported, using %.100s instead.", | |
1453 | cipher_name(ssh_cipher_default), | |
1454 | cipher_name(SSH_FALLBACK_CIPHER)); | |
1455 | options.cipher = SSH_FALLBACK_CIPHER; | |
1456 | } | |
1457 | } | |
1458 | /* Check that the selected cipher is supported. */ | |
1459 | if (!(supported_ciphers & (1 << options.cipher))) | |
1460 | fatal("Selected cipher type %.100s not supported by server.", | |
1461 | cipher_name(options.cipher)); | |
1462 | ||
1463 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1464 | ||
1465 | /* Send the encrypted session key to the server. */ | |
1466 | packet_start(SSH_CMSG_SESSION_KEY); | |
1467 | packet_put_char(options.cipher); | |
1468 | ||
1469 | /* Send the check bytes back to the server. */ | |
1470 | for (i = 0; i < 8; i++) | |
1471 | packet_put_char(check_bytes[i]); | |
1472 | ||
1473 | /* Send the encrypted encryption key. */ | |
1474 | packet_put_bignum(key); | |
1475 | ||
1476 | /* Send protocol flags. */ | |
95f1eccc | 1477 | packet_put_int(client_flags); |
5260325f | 1478 | |
1479 | /* Send the packet now. */ | |
8efc0c15 | 1480 | packet_send(); |
1481 | packet_write_wait(); | |
5260325f | 1482 | |
1483 | /* Destroy the session key integer and the public keys since we no longer need them. */ | |
1484 | BN_clear_free(key); | |
1485 | RSA_free(public_key); | |
1486 | RSA_free(host_key); | |
1487 | ||
1488 | debug("Sent encrypted session key."); | |
1489 | ||
1490 | /* Set the encryption key. */ | |
1491 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1492 | ||
1493 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1494 | memset(session_key, 0, sizeof(session_key)); | |
1495 | ||
aa3378df | 1496 | /* |
1497 | * Expect a success message from the server. Note that this message | |
1498 | * will be received in encrypted form. | |
1499 | */ | |
5260325f | 1500 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); |
1501 | ||
1502 | debug("Received encrypted confirmation."); | |
1503 | ||
1504 | /* Send the name of the user to log in as on the server. */ | |
1505 | packet_start(SSH_CMSG_USER); | |
1506 | packet_put_string(server_user, strlen(server_user)); | |
1507 | packet_send(); | |
1508 | packet_write_wait(); | |
1509 | ||
aa3378df | 1510 | /* |
1511 | * The server should respond with success if no authentication is | |
1512 | * needed (the user has no password). Otherwise the server responds | |
1513 | * with failure. | |
1514 | */ | |
8efc0c15 | 1515 | type = packet_read(&payload_len); |
5260325f | 1516 | |
1517 | /* check whether the connection was accepted without authentication. */ | |
8efc0c15 | 1518 | if (type == SSH_SMSG_SUCCESS) |
5260325f | 1519 | return; |
8efc0c15 | 1520 | if (type != SSH_SMSG_FAILURE) |
5260325f | 1521 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", |
1522 | type); | |
1523 | ||
1524 | #ifdef AFS | |
1525 | /* Try Kerberos tgt passing if the server supports it. */ | |
1526 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1527 | options.kerberos_tgt_passing) { | |
1528 | if (options.cipher == SSH_CIPHER_NONE) | |
1529 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1530 | (void) send_kerberos_tgt(); | |
1531 | } | |
1532 | /* Try AFS token passing if the server supports it. */ | |
1533 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1534 | options.afs_token_passing && k_hasafs()) { | |
1535 | if (options.cipher == SSH_CIPHER_NONE) | |
1536 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1537 | send_afs_tokens(); | |
1538 | } | |
1539 | #endif /* AFS */ | |
8efc0c15 | 1540 | |
5260325f | 1541 | #ifdef KRB4 |
1542 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1543 | options.kerberos_authentication) { | |
1544 | debug("Trying Kerberos authentication."); | |
1545 | if (try_kerberos_authentication()) { | |
1546 | /* The server should respond with success or failure. */ | |
1547 | type = packet_read(&payload_len); | |
1548 | if (type == SSH_SMSG_SUCCESS) | |
1549 | return; | |
1550 | if (type != SSH_SMSG_FAILURE) | |
1551 | packet_disconnect("Protocol error: got %d in response to Kerberos auth", type); | |
1552 | } | |
1553 | } | |
1554 | #endif /* KRB4 */ | |
1555 | ||
aa3378df | 1556 | /* |
1557 | * Use rhosts authentication if running in privileged socket and we | |
1558 | * do not wish to remain anonymous. | |
1559 | */ | |
5260325f | 1560 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && |
1561 | options.rhosts_authentication) { | |
1562 | debug("Trying rhosts authentication."); | |
1563 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
1564 | packet_put_string(local_user, strlen(local_user)); | |
1565 | packet_send(); | |
1566 | packet_write_wait(); | |
1567 | ||
1568 | /* The server should respond with success or failure. */ | |
1569 | type = packet_read(&payload_len); | |
1570 | if (type == SSH_SMSG_SUCCESS) | |
1571 | return; | |
1572 | if (type != SSH_SMSG_FAILURE) | |
1573 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1574 | type); | |
1575 | } | |
aa3378df | 1576 | /* |
1577 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1578 | * authentication. | |
1579 | */ | |
5260325f | 1580 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && |
1581 | options.rhosts_rsa_authentication && host_key_valid) { | |
1582 | if (try_rhosts_rsa_authentication(local_user, own_host_key)) | |
1583 | return; | |
1584 | } | |
1585 | /* Try RSA authentication if the server supports it. */ | |
1586 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1587 | options.rsa_authentication) { | |
aa3378df | 1588 | /* |
1589 | * Try RSA authentication using the authentication agent. The | |
1590 | * agent is tried first because no passphrase is needed for | |
1591 | * it, whereas identity files may require passphrases. | |
1592 | */ | |
5260325f | 1593 | if (try_agent_authentication()) |
1594 | return; | |
1595 | ||
1596 | /* Try RSA authentication for each identity. */ | |
1597 | for (i = 0; i < options.num_identity_files; i++) | |
57112b5a | 1598 | if (try_rsa_authentication(options.identity_files[i])) |
5260325f | 1599 | return; |
1600 | } | |
1601 | /* Try skey authentication if the server supports it. */ | |
1602 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && | |
1603 | options.skey_authentication && !options.batch_mode) { | |
57112b5a | 1604 | if (try_skey_authentication()) |
1605 | return; | |
5260325f | 1606 | } |
1607 | /* Try password authentication if the server supports it. */ | |
1608 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1609 | options.password_authentication && !options.batch_mode) { | |
1610 | char prompt[80]; | |
a408af76 | 1611 | |
57112b5a | 1612 | snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ", |
a408af76 | 1613 | server_user, host); |
57112b5a | 1614 | if (try_password_authentication(prompt)) |
1615 | return; | |
5260325f | 1616 | } |
1617 | /* All authentication methods have failed. Exit with an error message. */ | |
1618 | fatal("Permission denied."); | |
1619 | /* NOTREACHED */ | |
8efc0c15 | 1620 | } |