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1 | /* | |
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 | * Code to connect to a remote host, and to perform the client side of the | |
6 | * login (authentication) dialog. | |
7 | * | |
8 | * As far as I am concerned, the code I have written for this software | |
9 | * can be used freely for any purpose. Any derived versions of this | |
10 | * software must be clearly marked as such, and if the derived work is | |
11 | * incompatible with the protocol description in the RFC file, it must be | |
12 | * called by a name other than "ssh" or "Secure Shell". | |
13 | */ | |
14 | ||
15 | #include "includes.h" | |
16 | RCSID("$OpenBSD: sshconnect1.c,v 1.38 2001/06/26 20:14:11 markus Exp $"); | |
17 | ||
18 | #include <openssl/bn.h> | |
19 | #include <openssl/evp.h> | |
20 | ||
21 | #ifdef KRB4 | |
22 | #include <krb.h> | |
23 | #endif | |
24 | #ifdef KRB5 | |
25 | #include <krb5.h> | |
26 | #endif | |
27 | #ifdef AFS | |
28 | #include <kafs.h> | |
29 | #include "radix.h" | |
30 | #endif | |
31 | ||
32 | #include "ssh.h" | |
33 | #include "ssh1.h" | |
34 | #include "xmalloc.h" | |
35 | #include "rsa.h" | |
36 | #include "buffer.h" | |
37 | #include "packet.h" | |
38 | #include "mpaux.h" | |
39 | #include "uidswap.h" | |
40 | #include "log.h" | |
41 | #include "readconf.h" | |
42 | #include "key.h" | |
43 | #include "authfd.h" | |
44 | #include "sshconnect.h" | |
45 | #include "authfile.h" | |
46 | #include "readpass.h" | |
47 | #include "cipher.h" | |
48 | #include "canohost.h" | |
49 | #include "auth.h" | |
50 | ||
51 | /* Session id for the current session. */ | |
52 | u_char session_id[16]; | |
53 | u_int supported_authentications = 0; | |
54 | ||
55 | extern Options options; | |
56 | extern char *__progname; | |
57 | ||
58 | /* | |
59 | * Checks if the user has an authentication agent, and if so, tries to | |
60 | * authenticate using the agent. | |
61 | */ | |
62 | static int | |
63 | try_agent_authentication(void) | |
64 | { | |
65 | int type; | |
66 | char *comment; | |
67 | AuthenticationConnection *auth; | |
68 | u_char response[16]; | |
69 | u_int i; | |
70 | int plen, clen; | |
71 | Key *key; | |
72 | BIGNUM *challenge; | |
73 | ||
74 | /* Get connection to the agent. */ | |
75 | auth = ssh_get_authentication_connection(); | |
76 | if (!auth) | |
77 | return 0; | |
78 | ||
79 | challenge = BN_new(); | |
80 | ||
81 | /* Loop through identities served by the agent. */ | |
82 | for (key = ssh_get_first_identity(auth, &comment, 1); | |
83 | key != NULL; | |
84 | key = ssh_get_next_identity(auth, &comment, 1)) { | |
85 | ||
86 | /* Try this identity. */ | |
87 | debug("Trying RSA authentication via agent with '%.100s'", comment); | |
88 | xfree(comment); | |
89 | ||
90 | /* Tell the server that we are willing to authenticate using this key. */ | |
91 | packet_start(SSH_CMSG_AUTH_RSA); | |
92 | packet_put_bignum(key->rsa->n); | |
93 | packet_send(); | |
94 | packet_write_wait(); | |
95 | ||
96 | /* Wait for server's response. */ | |
97 | type = packet_read(&plen); | |
98 | ||
99 | /* The server sends failure if it doesn\'t like our key or | |
100 | does not support RSA authentication. */ | |
101 | if (type == SSH_SMSG_FAILURE) { | |
102 | debug("Server refused our key."); | |
103 | key_free(key); | |
104 | continue; | |
105 | } | |
106 | /* Otherwise it should have sent a challenge. */ | |
107 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
108 | packet_disconnect("Protocol error during RSA authentication: %d", | |
109 | type); | |
110 | ||
111 | packet_get_bignum(challenge, &clen); | |
112 | ||
113 | packet_integrity_check(plen, clen, type); | |
114 | ||
115 | debug("Received RSA challenge from server."); | |
116 | ||
117 | /* Ask the agent to decrypt the challenge. */ | |
118 | if (!ssh_decrypt_challenge(auth, key, challenge, session_id, 1, response)) { | |
119 | /* | |
120 | * The agent failed to authenticate this identifier | |
121 | * although it advertised it supports this. Just | |
122 | * return a wrong value. | |
123 | */ | |
124 | log("Authentication agent failed to decrypt challenge."); | |
125 | memset(response, 0, sizeof(response)); | |
126 | } | |
127 | key_free(key); | |
128 | debug("Sending response to RSA challenge."); | |
129 | ||
130 | /* Send the decrypted challenge back to the server. */ | |
131 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
132 | for (i = 0; i < 16; i++) | |
133 | packet_put_char(response[i]); | |
134 | packet_send(); | |
135 | packet_write_wait(); | |
136 | ||
137 | /* Wait for response from the server. */ | |
138 | type = packet_read(&plen); | |
139 | ||
140 | /* The server returns success if it accepted the authentication. */ | |
141 | if (type == SSH_SMSG_SUCCESS) { | |
142 | ssh_close_authentication_connection(auth); | |
143 | BN_clear_free(challenge); | |
144 | debug("RSA authentication accepted by server."); | |
145 | return 1; | |
146 | } | |
147 | /* Otherwise it should return failure. */ | |
148 | if (type != SSH_SMSG_FAILURE) | |
149 | packet_disconnect("Protocol error waiting RSA auth response: %d", | |
150 | type); | |
151 | } | |
152 | ssh_close_authentication_connection(auth); | |
153 | BN_clear_free(challenge); | |
154 | debug("RSA authentication using agent refused."); | |
155 | return 0; | |
156 | } | |
157 | ||
158 | /* | |
159 | * Computes the proper response to a RSA challenge, and sends the response to | |
160 | * the server. | |
161 | */ | |
162 | static void | |
163 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) | |
164 | { | |
165 | u_char buf[32], response[16]; | |
166 | MD5_CTX md; | |
167 | int i, len; | |
168 | ||
169 | /* Decrypt the challenge using the private key. */ | |
170 | /* XXX think about Bleichenbacher, too */ | |
171 | if (rsa_private_decrypt(challenge, challenge, prv) <= 0) | |
172 | packet_disconnect( | |
173 | "respond_to_rsa_challenge: rsa_private_decrypt failed"); | |
174 | ||
175 | /* Compute the response. */ | |
176 | /* The response is MD5 of decrypted challenge plus session id. */ | |
177 | len = BN_num_bytes(challenge); | |
178 | if (len <= 0 || len > sizeof(buf)) | |
179 | packet_disconnect( | |
180 | "respond_to_rsa_challenge: bad challenge length %d", len); | |
181 | ||
182 | memset(buf, 0, sizeof(buf)); | |
183 | BN_bn2bin(challenge, buf + sizeof(buf) - len); | |
184 | MD5_Init(&md); | |
185 | MD5_Update(&md, buf, 32); | |
186 | MD5_Update(&md, session_id, 16); | |
187 | MD5_Final(response, &md); | |
188 | ||
189 | debug("Sending response to host key RSA challenge."); | |
190 | ||
191 | /* Send the response back to the server. */ | |
192 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
193 | for (i = 0; i < 16; i++) | |
194 | packet_put_char(response[i]); | |
195 | packet_send(); | |
196 | packet_write_wait(); | |
197 | ||
198 | memset(buf, 0, sizeof(buf)); | |
199 | memset(response, 0, sizeof(response)); | |
200 | memset(&md, 0, sizeof(md)); | |
201 | } | |
202 | ||
203 | /* | |
204 | * Checks if the user has authentication file, and if so, tries to authenticate | |
205 | * the user using it. | |
206 | */ | |
207 | static int | |
208 | try_rsa_authentication(int idx) | |
209 | { | |
210 | BIGNUM *challenge; | |
211 | Key *public, *private; | |
212 | char buf[300], *passphrase, *comment, *authfile; | |
213 | int i, type, quit, plen, clen; | |
214 | ||
215 | public = options.identity_keys[idx]; | |
216 | authfile = options.identity_files[idx]; | |
217 | comment = xstrdup(authfile); | |
218 | ||
219 | debug("Trying RSA authentication with key '%.100s'", comment); | |
220 | ||
221 | /* Tell the server that we are willing to authenticate using this key. */ | |
222 | packet_start(SSH_CMSG_AUTH_RSA); | |
223 | packet_put_bignum(public->rsa->n); | |
224 | packet_send(); | |
225 | packet_write_wait(); | |
226 | ||
227 | /* Wait for server's response. */ | |
228 | type = packet_read(&plen); | |
229 | ||
230 | /* | |
231 | * The server responds with failure if it doesn\'t like our key or | |
232 | * doesn\'t support RSA authentication. | |
233 | */ | |
234 | if (type == SSH_SMSG_FAILURE) { | |
235 | debug("Server refused our key."); | |
236 | xfree(comment); | |
237 | return 0; | |
238 | } | |
239 | /* Otherwise, the server should respond with a challenge. */ | |
240 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
241 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
242 | ||
243 | /* Get the challenge from the packet. */ | |
244 | challenge = BN_new(); | |
245 | packet_get_bignum(challenge, &clen); | |
246 | ||
247 | packet_integrity_check(plen, clen, type); | |
248 | ||
249 | debug("Received RSA challenge from server."); | |
250 | ||
251 | /* | |
252 | * If the key is not stored in external hardware, we have to | |
253 | * load the private key. Try first with empty passphrase; if it | |
254 | * fails, ask for a passphrase. | |
255 | */ | |
256 | if (public->flags && KEY_FLAG_EXT) | |
257 | private = public; | |
258 | else | |
259 | private = key_load_private_type(KEY_RSA1, authfile, "", NULL); | |
260 | if (private == NULL && !options.batch_mode) { | |
261 | snprintf(buf, sizeof(buf), | |
262 | "Enter passphrase for RSA key '%.100s': ", comment); | |
263 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
264 | passphrase = read_passphrase(buf, 0); | |
265 | if (strcmp(passphrase, "") != 0) { | |
266 | private = key_load_private_type(KEY_RSA1, | |
267 | authfile, passphrase, NULL); | |
268 | quit = 0; | |
269 | } else { | |
270 | debug2("no passphrase given, try next key"); | |
271 | quit = 1; | |
272 | } | |
273 | memset(passphrase, 0, strlen(passphrase)); | |
274 | xfree(passphrase); | |
275 | if (private != NULL || quit) | |
276 | break; | |
277 | debug2("bad passphrase given, try again..."); | |
278 | } | |
279 | } | |
280 | /* We no longer need the comment. */ | |
281 | xfree(comment); | |
282 | ||
283 | if (private == NULL) { | |
284 | if (!options.batch_mode) | |
285 | error("Bad passphrase."); | |
286 | ||
287 | /* Send a dummy response packet to avoid protocol error. */ | |
288 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
289 | for (i = 0; i < 16; i++) | |
290 | packet_put_char(0); | |
291 | packet_send(); | |
292 | packet_write_wait(); | |
293 | ||
294 | /* Expect the server to reject it... */ | |
295 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
296 | BN_clear_free(challenge); | |
297 | return 0; | |
298 | } | |
299 | ||
300 | /* Compute and send a response to the challenge. */ | |
301 | respond_to_rsa_challenge(challenge, private->rsa); | |
302 | ||
303 | /* Destroy the private key unless it in external hardware. */ | |
304 | if (!(private->flags & KEY_FLAG_EXT)) | |
305 | key_free(private); | |
306 | ||
307 | /* We no longer need the challenge. */ | |
308 | BN_clear_free(challenge); | |
309 | ||
310 | /* Wait for response from the server. */ | |
311 | type = packet_read(&plen); | |
312 | if (type == SSH_SMSG_SUCCESS) { | |
313 | debug("RSA authentication accepted by server."); | |
314 | return 1; | |
315 | } | |
316 | if (type != SSH_SMSG_FAILURE) | |
317 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
318 | debug("RSA authentication refused."); | |
319 | return 0; | |
320 | } | |
321 | ||
322 | /* | |
323 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
324 | * authentication and RSA host authentication. | |
325 | */ | |
326 | static int | |
327 | try_rhosts_rsa_authentication(const char *local_user, Key * host_key) | |
328 | { | |
329 | int type; | |
330 | BIGNUM *challenge; | |
331 | int plen, clen; | |
332 | ||
333 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
334 | ||
335 | /* Tell the server that we are willing to authenticate using this key. */ | |
336 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
337 | packet_put_cstring(local_user); | |
338 | packet_put_int(BN_num_bits(host_key->rsa->n)); | |
339 | packet_put_bignum(host_key->rsa->e); | |
340 | packet_put_bignum(host_key->rsa->n); | |
341 | packet_send(); | |
342 | packet_write_wait(); | |
343 | ||
344 | /* Wait for server's response. */ | |
345 | type = packet_read(&plen); | |
346 | ||
347 | /* The server responds with failure if it doesn't admit our | |
348 | .rhosts authentication or doesn't know our host key. */ | |
349 | if (type == SSH_SMSG_FAILURE) { | |
350 | debug("Server refused our rhosts authentication or host key."); | |
351 | return 0; | |
352 | } | |
353 | /* Otherwise, the server should respond with a challenge. */ | |
354 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
355 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
356 | ||
357 | /* Get the challenge from the packet. */ | |
358 | challenge = BN_new(); | |
359 | packet_get_bignum(challenge, &clen); | |
360 | ||
361 | packet_integrity_check(plen, clen, type); | |
362 | ||
363 | debug("Received RSA challenge for host key from server."); | |
364 | ||
365 | /* Compute a response to the challenge. */ | |
366 | respond_to_rsa_challenge(challenge, host_key->rsa); | |
367 | ||
368 | /* We no longer need the challenge. */ | |
369 | BN_clear_free(challenge); | |
370 | ||
371 | /* Wait for response from the server. */ | |
372 | type = packet_read(&plen); | |
373 | if (type == SSH_SMSG_SUCCESS) { | |
374 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
375 | return 1; | |
376 | } | |
377 | if (type != SSH_SMSG_FAILURE) | |
378 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
379 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
380 | return 0; | |
381 | } | |
382 | ||
383 | #ifdef KRB4 | |
384 | static int | |
385 | try_krb4_authentication(void) | |
386 | { | |
387 | KTEXT_ST auth; /* Kerberos data */ | |
388 | char *reply; | |
389 | char inst[INST_SZ]; | |
390 | char *realm; | |
391 | CREDENTIALS cred; | |
392 | int r, type, plen; | |
393 | socklen_t slen; | |
394 | Key_schedule schedule; | |
395 | u_long checksum, cksum; | |
396 | MSG_DAT msg_data; | |
397 | struct sockaddr_in local, foreign; | |
398 | struct stat st; | |
399 | ||
400 | /* Don't do anything if we don't have any tickets. */ | |
401 | if (stat(tkt_string(), &st) < 0) | |
402 | return 0; | |
403 | ||
404 | strlcpy(inst, (char *)krb_get_phost(get_canonical_hostname(1)), | |
405 | INST_SZ); | |
406 | ||
407 | realm = (char *)krb_realmofhost(get_canonical_hostname(1)); | |
408 | if (!realm) { | |
409 | debug("Kerberos v4: no realm for %s", get_canonical_hostname(1)); | |
410 | return 0; | |
411 | } | |
412 | /* This can really be anything. */ | |
413 | checksum = (u_long)getpid(); | |
414 | ||
415 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); | |
416 | if (r != KSUCCESS) { | |
417 | debug("Kerberos v4 krb_mk_req failed: %s", krb_err_txt[r]); | |
418 | return 0; | |
419 | } | |
420 | /* Get session key to decrypt the server's reply with. */ | |
421 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
422 | if (r != KSUCCESS) { | |
423 | debug("get_cred failed: %s", krb_err_txt[r]); | |
424 | return 0; | |
425 | } | |
426 | des_key_sched((des_cblock *) cred.session, schedule); | |
427 | ||
428 | /* Send authentication info to server. */ | |
429 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
430 | packet_put_string((char *) auth.dat, auth.length); | |
431 | packet_send(); | |
432 | packet_write_wait(); | |
433 | ||
434 | /* Zero the buffer. */ | |
435 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
436 | ||
437 | slen = sizeof(local); | |
438 | memset(&local, 0, sizeof(local)); | |
439 | if (getsockname(packet_get_connection_in(), | |
440 | (struct sockaddr *)&local, &slen) < 0) | |
441 | debug("getsockname failed: %s", strerror(errno)); | |
442 | ||
443 | slen = sizeof(foreign); | |
444 | memset(&foreign, 0, sizeof(foreign)); | |
445 | if (getpeername(packet_get_connection_in(), | |
446 | (struct sockaddr *)&foreign, &slen) < 0) { | |
447 | debug("getpeername failed: %s", strerror(errno)); | |
448 | fatal_cleanup(); | |
449 | } | |
450 | /* Get server reply. */ | |
451 | type = packet_read(&plen); | |
452 | switch (type) { | |
453 | case SSH_SMSG_FAILURE: | |
454 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
455 | debug("Kerberos v4 authentication failed."); | |
456 | return 0; | |
457 | break; | |
458 | ||
459 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
460 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
461 | debug("Kerberos v4 authentication accepted."); | |
462 | ||
463 | /* Get server's response. */ | |
464 | reply = packet_get_string((u_int *) &auth.length); | |
465 | memcpy(auth.dat, reply, auth.length); | |
466 | xfree(reply); | |
467 | ||
468 | packet_integrity_check(plen, 4 + auth.length, type); | |
469 | ||
470 | /* | |
471 | * If his response isn't properly encrypted with the session | |
472 | * key, and the decrypted checksum fails to match, he's | |
473 | * bogus. Bail out. | |
474 | */ | |
475 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, | |
476 | &foreign, &local, &msg_data); | |
477 | if (r != KSUCCESS) { | |
478 | debug("Kerberos v4 krb_rd_priv failed: %s", | |
479 | krb_err_txt[r]); | |
480 | packet_disconnect("Kerberos v4 challenge failed!"); | |
481 | } | |
482 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
483 | memcpy((char *)&cksum, (char *)msg_data.app_data, | |
484 | sizeof(cksum)); | |
485 | cksum = ntohl(cksum); | |
486 | ||
487 | /* If it matches, we're golden. */ | |
488 | if (cksum == checksum + 1) { | |
489 | debug("Kerberos v4 challenge successful."); | |
490 | return 1; | |
491 | } else | |
492 | packet_disconnect("Kerberos v4 challenge failed!"); | |
493 | break; | |
494 | ||
495 | default: | |
496 | packet_disconnect("Protocol error on Kerberos v4 response: %d", type); | |
497 | } | |
498 | return 0; | |
499 | } | |
500 | ||
501 | #endif /* KRB4 */ | |
502 | ||
503 | #ifdef KRB5 | |
504 | static int | |
505 | try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context) | |
506 | { | |
507 | krb5_error_code problem; | |
508 | const char *tkfile; | |
509 | struct stat buf; | |
510 | krb5_ccache ccache = NULL; | |
511 | const char *remotehost; | |
512 | krb5_data ap; | |
513 | int type, payload_len; | |
514 | krb5_ap_rep_enc_part *reply = NULL; | |
515 | int ret; | |
516 | ||
517 | memset(&ap, 0, sizeof(ap)); | |
518 | ||
519 | problem = krb5_init_context(context); | |
520 | if (problem) { | |
521 | debug("Kerberos v5: krb5_init_context failed"); | |
522 | ret = 0; | |
523 | goto out; | |
524 | } | |
525 | ||
526 | tkfile = krb5_cc_default_name(*context); | |
527 | if (strncmp(tkfile, "FILE:", 5) == 0) | |
528 | tkfile += 5; | |
529 | ||
530 | if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) { | |
531 | debug("Kerberos v5: could not get default ccache (permission denied)."); | |
532 | ret = 0; | |
533 | goto out; | |
534 | } | |
535 | ||
536 | problem = krb5_cc_default(*context, &ccache); | |
537 | if (problem) { | |
538 | debug("Kerberos v5: krb5_cc_default failed: %s", | |
539 | krb5_get_err_text(*context, problem)); | |
540 | ret = 0; | |
541 | goto out; | |
542 | } | |
543 | ||
544 | remotehost = get_canonical_hostname(1); | |
545 | ||
546 | problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED, | |
547 | "host", remotehost, NULL, ccache, &ap); | |
548 | if (problem) { | |
549 | debug("Kerberos v5: krb5_mk_req failed: %s", | |
550 | krb5_get_err_text(*context, problem)); | |
551 | ret = 0; | |
552 | goto out; | |
553 | } | |
554 | ||
555 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
556 | packet_put_string((char *) ap.data, ap.length); | |
557 | packet_send(); | |
558 | packet_write_wait(); | |
559 | ||
560 | xfree(ap.data); | |
561 | ap.length = 0; | |
562 | ||
563 | type = packet_read(&payload_len); | |
564 | switch (type) { | |
565 | case SSH_SMSG_FAILURE: | |
566 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
567 | debug("Kerberos v5 authentication failed."); | |
568 | ret = 0; | |
569 | break; | |
570 | ||
571 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
572 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
573 | debug("Kerberos v5 authentication accepted."); | |
574 | ||
575 | /* Get server's response. */ | |
576 | ap.data = packet_get_string((unsigned int *) &ap.length); | |
577 | ||
578 | packet_integrity_check(payload_len, 4 + ap.length, type); | |
579 | /* XXX je to dobre? */ | |
580 | ||
581 | problem = krb5_rd_rep(*context, *auth_context, &ap, &reply); | |
582 | if (problem) { | |
583 | ret = 0; | |
584 | } | |
585 | ret = 1; | |
586 | break; | |
587 | ||
588 | default: | |
589 | packet_disconnect("Protocol error on Kerberos v5 response: %d", | |
590 | type); | |
591 | ret = 0; | |
592 | break; | |
593 | ||
594 | } | |
595 | ||
596 | out: | |
597 | if (ccache != NULL) | |
598 | krb5_cc_close(*context, ccache); | |
599 | if (reply != NULL) | |
600 | krb5_free_ap_rep_enc_part(*context, reply); | |
601 | if (ap.length > 0) | |
602 | krb5_data_free(&ap); | |
603 | ||
604 | return (ret); | |
605 | } | |
606 | ||
607 | static void | |
608 | send_krb5_tgt(krb5_context context, krb5_auth_context auth_context) | |
609 | { | |
610 | int fd, type, payload_len; | |
611 | krb5_error_code problem; | |
612 | krb5_data outbuf; | |
613 | krb5_ccache ccache = NULL; | |
614 | krb5_creds creds; | |
615 | krb5_kdc_flags flags; | |
616 | const char *remotehost; | |
617 | ||
618 | memset(&creds, 0, sizeof(creds)); | |
619 | memset(&outbuf, 0, sizeof(outbuf)); | |
620 | ||
621 | fd = packet_get_connection_in(); | |
622 | ||
623 | problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd); | |
624 | if (problem) | |
625 | goto out; | |
626 | ||
627 | problem = krb5_cc_default(context, &ccache); | |
628 | if (problem) | |
629 | goto out; | |
630 | ||
631 | problem = krb5_cc_get_principal(context, ccache, &creds.client); | |
632 | if (problem) | |
633 | goto out; | |
634 | ||
635 | problem = krb5_build_principal(context, &creds.server, | |
636 | strlen(creds.client->realm), creds.client->realm, | |
637 | "krbtgt", creds.client->realm, NULL); | |
638 | if (problem) | |
639 | goto out; | |
640 | ||
641 | creds.times.endtime = 0; | |
642 | ||
643 | flags.i = 0; | |
644 | flags.b.forwarded = 1; | |
645 | flags.b.forwardable = krb5_config_get_bool(context, NULL, | |
646 | "libdefaults", "forwardable", NULL); | |
647 | ||
648 | remotehost = get_canonical_hostname(1); | |
649 | ||
650 | problem = krb5_get_forwarded_creds(context, auth_context, | |
651 | ccache, flags.i, remotehost, &creds, &outbuf); | |
652 | if (problem) | |
653 | goto out; | |
654 | ||
655 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
656 | packet_put_string((char *)outbuf.data, outbuf.length); | |
657 | packet_send(); | |
658 | packet_write_wait(); | |
659 | ||
660 | type = packet_read(&payload_len); | |
661 | ||
662 | if (type == SSH_SMSG_SUCCESS) { | |
663 | char *pname; | |
664 | ||
665 | krb5_unparse_name(context, creds.client, &pname); | |
666 | debug("Kerberos v5 TGT forwarded (%s).", pname); | |
667 | xfree(pname); | |
668 | } else | |
669 | debug("Kerberos v5 TGT forwarding failed."); | |
670 | ||
671 | return; | |
672 | ||
673 | out: | |
674 | if (problem) | |
675 | debug("Kerberos v5 TGT forwarding failed: %s", | |
676 | krb5_get_err_text(context, problem)); | |
677 | if (creds.client) | |
678 | krb5_free_principal(context, creds.client); | |
679 | if (creds.server) | |
680 | krb5_free_principal(context, creds.server); | |
681 | if (ccache) | |
682 | krb5_cc_close(context, ccache); | |
683 | if (outbuf.data) | |
684 | xfree(outbuf.data); | |
685 | } | |
686 | #endif /* KRB5 */ | |
687 | ||
688 | #ifdef AFS | |
689 | static void | |
690 | send_krb4_tgt(void) | |
691 | { | |
692 | CREDENTIALS *creds; | |
693 | struct stat st; | |
694 | char buffer[4096], pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; | |
695 | int problem, type, len; | |
696 | ||
697 | /* Don't do anything if we don't have any tickets. */ | |
698 | if (stat(tkt_string(), &st) < 0) | |
699 | return; | |
700 | ||
701 | creds = xmalloc(sizeof(*creds)); | |
702 | ||
703 | problem = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm); | |
704 | if (problem) | |
705 | goto out; | |
706 | ||
707 | problem = krb_get_cred("krbtgt", prealm, prealm, creds); | |
708 | if (problem) | |
709 | goto out; | |
710 | ||
711 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { | |
712 | problem = RD_AP_EXP; | |
713 | goto out; | |
714 | } | |
715 | creds_to_radix(creds, (u_char *)buffer, sizeof(buffer)); | |
716 | ||
717 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
718 | packet_put_cstring(buffer); | |
719 | packet_send(); | |
720 | packet_write_wait(); | |
721 | ||
722 | type = packet_read(&len); | |
723 | ||
724 | if (type == SSH_SMSG_SUCCESS) | |
725 | debug("Kerberos v4 TGT forwarded (%s%s%s@%s).", | |
726 | creds->pname, creds->pinst[0] ? "." : "", | |
727 | creds->pinst, creds->realm); | |
728 | else | |
729 | debug("Kerberos v4 TGT rejected."); | |
730 | ||
731 | xfree(creds); | |
732 | return; | |
733 | ||
734 | out: | |
735 | debug("Kerberos v4 TGT passing failed: %s", krb_err_txt[problem]); | |
736 | xfree(creds); | |
737 | } | |
738 | ||
739 | static void | |
740 | send_afs_tokens(void) | |
741 | { | |
742 | CREDENTIALS creds; | |
743 | struct ViceIoctl parms; | |
744 | struct ClearToken ct; | |
745 | int i, type, len; | |
746 | char buf[2048], *p, *server_cell; | |
747 | char buffer[8192]; | |
748 | ||
749 | /* Move over ktc_GetToken, here's something leaner. */ | |
750 | for (i = 0; i < 100; i++) { /* just in case */ | |
751 | parms.in = (char *) &i; | |
752 | parms.in_size = sizeof(i); | |
753 | parms.out = buf; | |
754 | parms.out_size = sizeof(buf); | |
755 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
756 | break; | |
757 | p = buf; | |
758 | ||
759 | /* Get secret token. */ | |
760 | memcpy(&creds.ticket_st.length, p, sizeof(u_int)); | |
761 | if (creds.ticket_st.length > MAX_KTXT_LEN) | |
762 | break; | |
763 | p += sizeof(u_int); | |
764 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); | |
765 | p += creds.ticket_st.length; | |
766 | ||
767 | /* Get clear token. */ | |
768 | memcpy(&len, p, sizeof(len)); | |
769 | if (len != sizeof(struct ClearToken)) | |
770 | break; | |
771 | p += sizeof(len); | |
772 | memcpy(&ct, p, len); | |
773 | p += len; | |
774 | p += sizeof(len); /* primary flag */ | |
775 | server_cell = p; | |
776 | ||
777 | /* Flesh out our credentials. */ | |
778 | strlcpy(creds.service, "afs", sizeof(creds.service)); | |
779 | creds.instance[0] = '\0'; | |
780 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
781 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
782 | creds.issue_date = ct.BeginTimestamp; | |
783 | creds.lifetime = krb_time_to_life(creds.issue_date, | |
784 | ct.EndTimestamp); | |
785 | creds.kvno = ct.AuthHandle; | |
786 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
787 | creds.pinst[0] = '\0'; | |
788 | ||
789 | /* Encode token, ship it off. */ | |
790 | if (creds_to_radix(&creds, (u_char *)buffer, | |
791 | sizeof(buffer)) <= 0) | |
792 | break; | |
793 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
794 | packet_put_cstring(buffer); | |
795 | packet_send(); | |
796 | packet_write_wait(); | |
797 | ||
798 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
799 | Victor? */ | |
800 | type = packet_read(&len); | |
801 | ||
802 | if (type == SSH_SMSG_FAILURE) | |
803 | debug("AFS token for cell %s rejected.", server_cell); | |
804 | else if (type != SSH_SMSG_SUCCESS) | |
805 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
806 | } | |
807 | } | |
808 | ||
809 | #endif /* AFS */ | |
810 | ||
811 | /* | |
812 | * Tries to authenticate with any string-based challenge/response system. | |
813 | * Note that the client code is not tied to s/key or TIS. | |
814 | */ | |
815 | static int | |
816 | try_challenge_response_authentication(void) | |
817 | { | |
818 | int type, i; | |
819 | int payload_len; | |
820 | u_int clen; | |
821 | char prompt[1024]; | |
822 | char *challenge, *response; | |
823 | ||
824 | debug("Doing challenge reponse authentication."); | |
825 | ||
826 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
827 | /* request a challenge */ | |
828 | packet_start(SSH_CMSG_AUTH_TIS); | |
829 | packet_send(); | |
830 | packet_write_wait(); | |
831 | ||
832 | type = packet_read(&payload_len); | |
833 | if (type != SSH_SMSG_FAILURE && | |
834 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
835 | packet_disconnect("Protocol error: got %d in response " | |
836 | "to SSH_CMSG_AUTH_TIS", type); | |
837 | } | |
838 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
839 | debug("No challenge."); | |
840 | return 0; | |
841 | } | |
842 | challenge = packet_get_string(&clen); | |
843 | packet_integrity_check(payload_len, (4 + clen), type); | |
844 | snprintf(prompt, sizeof prompt, "%s%s", challenge, | |
845 | strchr(challenge, '\n') ? "" : "\nResponse: "); | |
846 | xfree(challenge); | |
847 | if (i != 0) | |
848 | error("Permission denied, please try again."); | |
849 | if (options.cipher == SSH_CIPHER_NONE) | |
850 | log("WARNING: Encryption is disabled! " | |
851 | "Reponse will be transmitted in clear text."); | |
852 | response = read_passphrase(prompt, 0); | |
853 | if (strcmp(response, "") == 0) { | |
854 | xfree(response); | |
855 | break; | |
856 | } | |
857 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); | |
858 | ssh_put_password(response); | |
859 | memset(response, 0, strlen(response)); | |
860 | xfree(response); | |
861 | packet_send(); | |
862 | packet_write_wait(); | |
863 | type = packet_read(&payload_len); | |
864 | if (type == SSH_SMSG_SUCCESS) | |
865 | return 1; | |
866 | if (type != SSH_SMSG_FAILURE) | |
867 | packet_disconnect("Protocol error: got %d in response " | |
868 | "to SSH_CMSG_AUTH_TIS_RESPONSE", type); | |
869 | } | |
870 | /* failure */ | |
871 | return 0; | |
872 | } | |
873 | ||
874 | /* | |
875 | * Tries to authenticate with plain passwd authentication. | |
876 | */ | |
877 | static int | |
878 | try_password_authentication(char *prompt) | |
879 | { | |
880 | int type, i, payload_len; | |
881 | char *password; | |
882 | ||
883 | debug("Doing password authentication."); | |
884 | if (options.cipher == SSH_CIPHER_NONE) | |
885 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
886 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
887 | if (i != 0) | |
888 | error("Permission denied, please try again."); | |
889 | password = read_passphrase(prompt, 0); | |
890 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
891 | ssh_put_password(password); | |
892 | memset(password, 0, strlen(password)); | |
893 | xfree(password); | |
894 | packet_send(); | |
895 | packet_write_wait(); | |
896 | ||
897 | type = packet_read(&payload_len); | |
898 | if (type == SSH_SMSG_SUCCESS) | |
899 | return 1; | |
900 | if (type != SSH_SMSG_FAILURE) | |
901 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
902 | } | |
903 | /* failure */ | |
904 | return 0; | |
905 | } | |
906 | ||
907 | /* | |
908 | * SSH1 key exchange | |
909 | */ | |
910 | void | |
911 | ssh_kex(char *host, struct sockaddr *hostaddr) | |
912 | { | |
913 | int i; | |
914 | BIGNUM *key; | |
915 | RSA *host_key; | |
916 | RSA *public_key; | |
917 | Key k; | |
918 | int bits, rbits; | |
919 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
920 | u_char session_key[SSH_SESSION_KEY_LENGTH]; | |
921 | u_char cookie[8]; | |
922 | u_int supported_ciphers; | |
923 | u_int server_flags, client_flags; | |
924 | int payload_len, clen, sum_len = 0; | |
925 | u_int32_t rand = 0; | |
926 | ||
927 | debug("Waiting for server public key."); | |
928 | ||
929 | /* Wait for a public key packet from the server. */ | |
930 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
931 | ||
932 | /* Get cookie from the packet. */ | |
933 | for (i = 0; i < 8; i++) | |
934 | cookie[i] = packet_get_char(); | |
935 | ||
936 | /* Get the public key. */ | |
937 | public_key = RSA_new(); | |
938 | bits = packet_get_int();/* bits */ | |
939 | public_key->e = BN_new(); | |
940 | packet_get_bignum(public_key->e, &clen); | |
941 | sum_len += clen; | |
942 | public_key->n = BN_new(); | |
943 | packet_get_bignum(public_key->n, &clen); | |
944 | sum_len += clen; | |
945 | ||
946 | rbits = BN_num_bits(public_key->n); | |
947 | if (bits != rbits) { | |
948 | log("Warning: Server lies about size of server public key: " | |
949 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
950 | log("Warning: This may be due to an old implementation of ssh."); | |
951 | } | |
952 | /* Get the host key. */ | |
953 | host_key = RSA_new(); | |
954 | bits = packet_get_int();/* bits */ | |
955 | host_key->e = BN_new(); | |
956 | packet_get_bignum(host_key->e, &clen); | |
957 | sum_len += clen; | |
958 | host_key->n = BN_new(); | |
959 | packet_get_bignum(host_key->n, &clen); | |
960 | sum_len += clen; | |
961 | ||
962 | rbits = BN_num_bits(host_key->n); | |
963 | if (bits != rbits) { | |
964 | log("Warning: Server lies about size of server host key: " | |
965 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
966 | log("Warning: This may be due to an old implementation of ssh."); | |
967 | } | |
968 | ||
969 | /* Get protocol flags. */ | |
970 | server_flags = packet_get_int(); | |
971 | packet_set_protocol_flags(server_flags); | |
972 | ||
973 | supported_ciphers = packet_get_int(); | |
974 | supported_authentications = packet_get_int(); | |
975 | ||
976 | debug("Received server public key (%d bits) and host key (%d bits).", | |
977 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
978 | ||
979 | packet_integrity_check(payload_len, | |
980 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
981 | SSH_SMSG_PUBLIC_KEY); | |
982 | k.type = KEY_RSA1; | |
983 | k.rsa = host_key; | |
984 | if (verify_host_key(host, hostaddr, &k) == -1) | |
985 | fatal("host_key verification failed"); | |
986 | ||
987 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; | |
988 | ||
989 | compute_session_id(session_id, cookie, host_key->n, public_key->n); | |
990 | ||
991 | /* Generate a session key. */ | |
992 | arc4random_stir(); | |
993 | ||
994 | /* | |
995 | * Generate an encryption key for the session. The key is a 256 bit | |
996 | * random number, interpreted as a 32-byte key, with the least | |
997 | * significant 8 bits being the first byte of the key. | |
998 | */ | |
999 | for (i = 0; i < 32; i++) { | |
1000 | if (i % 4 == 0) | |
1001 | rand = arc4random(); | |
1002 | session_key[i] = rand & 0xff; | |
1003 | rand >>= 8; | |
1004 | } | |
1005 | ||
1006 | /* | |
1007 | * According to the protocol spec, the first byte of the session key | |
1008 | * is the highest byte of the integer. The session key is xored with | |
1009 | * the first 16 bytes of the session id. | |
1010 | */ | |
1011 | key = BN_new(); | |
1012 | BN_set_word(key, 0); | |
1013 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1014 | BN_lshift(key, key, 8); | |
1015 | if (i < 16) | |
1016 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1017 | else | |
1018 | BN_add_word(key, session_key[i]); | |
1019 | } | |
1020 | ||
1021 | /* | |
1022 | * Encrypt the integer using the public key and host key of the | |
1023 | * server (key with smaller modulus first). | |
1024 | */ | |
1025 | if (BN_cmp(public_key->n, host_key->n) < 0) { | |
1026 | /* Public key has smaller modulus. */ | |
1027 | if (BN_num_bits(host_key->n) < | |
1028 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1029 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1030 | "SSH_KEY_BITS_RESERVED %d", | |
1031 | BN_num_bits(host_key->n), | |
1032 | BN_num_bits(public_key->n), | |
1033 | SSH_KEY_BITS_RESERVED); | |
1034 | } | |
1035 | rsa_public_encrypt(key, key, public_key); | |
1036 | rsa_public_encrypt(key, key, host_key); | |
1037 | } else { | |
1038 | /* Host key has smaller modulus (or they are equal). */ | |
1039 | if (BN_num_bits(public_key->n) < | |
1040 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1041 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1042 | "SSH_KEY_BITS_RESERVED %d", | |
1043 | BN_num_bits(public_key->n), | |
1044 | BN_num_bits(host_key->n), | |
1045 | SSH_KEY_BITS_RESERVED); | |
1046 | } | |
1047 | rsa_public_encrypt(key, key, host_key); | |
1048 | rsa_public_encrypt(key, key, public_key); | |
1049 | } | |
1050 | ||
1051 | /* Destroy the public keys since we no longer need them. */ | |
1052 | RSA_free(public_key); | |
1053 | RSA_free(host_key); | |
1054 | ||
1055 | if (options.cipher == SSH_CIPHER_NOT_SET) { | |
1056 | if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default)) | |
1057 | options.cipher = ssh_cipher_default; | |
1058 | } else if (options.cipher == SSH_CIPHER_ILLEGAL || | |
1059 | !(cipher_mask_ssh1(1) & (1 << options.cipher))) { | |
1060 | log("No valid SSH1 cipher, using %.100s instead.", | |
1061 | cipher_name(ssh_cipher_default)); | |
1062 | options.cipher = ssh_cipher_default; | |
1063 | } | |
1064 | /* Check that the selected cipher is supported. */ | |
1065 | if (!(supported_ciphers & (1 << options.cipher))) | |
1066 | fatal("Selected cipher type %.100s not supported by server.", | |
1067 | cipher_name(options.cipher)); | |
1068 | ||
1069 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1070 | ||
1071 | /* Send the encrypted session key to the server. */ | |
1072 | packet_start(SSH_CMSG_SESSION_KEY); | |
1073 | packet_put_char(options.cipher); | |
1074 | ||
1075 | /* Send the cookie back to the server. */ | |
1076 | for (i = 0; i < 8; i++) | |
1077 | packet_put_char(cookie[i]); | |
1078 | ||
1079 | /* Send and destroy the encrypted encryption key integer. */ | |
1080 | packet_put_bignum(key); | |
1081 | BN_clear_free(key); | |
1082 | ||
1083 | /* Send protocol flags. */ | |
1084 | packet_put_int(client_flags); | |
1085 | ||
1086 | /* Send the packet now. */ | |
1087 | packet_send(); | |
1088 | packet_write_wait(); | |
1089 | ||
1090 | debug("Sent encrypted session key."); | |
1091 | ||
1092 | /* Set the encryption key. */ | |
1093 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1094 | ||
1095 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1096 | memset(session_key, 0, sizeof(session_key)); | |
1097 | ||
1098 | /* | |
1099 | * Expect a success message from the server. Note that this message | |
1100 | * will be received in encrypted form. | |
1101 | */ | |
1102 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); | |
1103 | ||
1104 | debug("Received encrypted confirmation."); | |
1105 | } | |
1106 | ||
1107 | /* | |
1108 | * Authenticate user | |
1109 | */ | |
1110 | void | |
1111 | ssh_userauth1(const char *local_user, const char *server_user, char *host, | |
1112 | Key **keys, int nkeys) | |
1113 | { | |
1114 | #ifdef KRB5 | |
1115 | krb5_context context = NULL; | |
1116 | krb5_auth_context auth_context = NULL; | |
1117 | #endif | |
1118 | int i, type; | |
1119 | int payload_len; | |
1120 | ||
1121 | if (supported_authentications == 0) | |
1122 | fatal("ssh_userauth1: server supports no auth methods"); | |
1123 | ||
1124 | /* Send the name of the user to log in as on the server. */ | |
1125 | packet_start(SSH_CMSG_USER); | |
1126 | packet_put_cstring(server_user); | |
1127 | packet_send(); | |
1128 | packet_write_wait(); | |
1129 | ||
1130 | /* | |
1131 | * The server should respond with success if no authentication is | |
1132 | * needed (the user has no password). Otherwise the server responds | |
1133 | * with failure. | |
1134 | */ | |
1135 | type = packet_read(&payload_len); | |
1136 | ||
1137 | /* check whether the connection was accepted without authentication. */ | |
1138 | if (type == SSH_SMSG_SUCCESS) | |
1139 | goto success; | |
1140 | if (type != SSH_SMSG_FAILURE) | |
1141 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type); | |
1142 | ||
1143 | #ifdef KRB5 | |
1144 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1145 | options.kerberos_authentication) { | |
1146 | debug("Trying Kerberos v5 authentication."); | |
1147 | ||
1148 | if (try_krb5_authentication(&context, &auth_context)) { | |
1149 | type = packet_read(&payload_len); | |
1150 | if (type == SSH_SMSG_SUCCESS) | |
1151 | goto success; | |
1152 | if (type != SSH_SMSG_FAILURE) | |
1153 | packet_disconnect("Protocol error: got %d in response to Kerberos v5 auth", type); | |
1154 | } | |
1155 | } | |
1156 | #endif /* KRB5 */ | |
1157 | ||
1158 | #ifdef KRB4 | |
1159 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1160 | options.kerberos_authentication) { | |
1161 | debug("Trying Kerberos v4 authentication."); | |
1162 | ||
1163 | if (try_krb4_authentication()) { | |
1164 | type = packet_read(&payload_len); | |
1165 | if (type == SSH_SMSG_SUCCESS) | |
1166 | goto success; | |
1167 | if (type != SSH_SMSG_FAILURE) | |
1168 | packet_disconnect("Protocol error: got %d in response to Kerberos v4 auth", type); | |
1169 | } | |
1170 | } | |
1171 | #endif /* KRB4 */ | |
1172 | ||
1173 | /* | |
1174 | * Use rhosts authentication if running in privileged socket and we | |
1175 | * do not wish to remain anonymous. | |
1176 | */ | |
1177 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && | |
1178 | options.rhosts_authentication) { | |
1179 | debug("Trying rhosts authentication."); | |
1180 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
1181 | packet_put_cstring(local_user); | |
1182 | packet_send(); | |
1183 | packet_write_wait(); | |
1184 | ||
1185 | /* The server should respond with success or failure. */ | |
1186 | type = packet_read(&payload_len); | |
1187 | if (type == SSH_SMSG_SUCCESS) | |
1188 | goto success; | |
1189 | if (type != SSH_SMSG_FAILURE) | |
1190 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1191 | type); | |
1192 | } | |
1193 | /* | |
1194 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1195 | * authentication. | |
1196 | */ | |
1197 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && | |
1198 | options.rhosts_rsa_authentication) { | |
1199 | for (i = 0; i < nkeys; i++) { | |
1200 | if (keys[i] != NULL && keys[i]->type == KEY_RSA1 && | |
1201 | try_rhosts_rsa_authentication(local_user, keys[i])) | |
1202 | goto success; | |
1203 | } | |
1204 | } | |
1205 | /* Try RSA authentication if the server supports it. */ | |
1206 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1207 | options.rsa_authentication) { | |
1208 | /* | |
1209 | * Try RSA authentication using the authentication agent. The | |
1210 | * agent is tried first because no passphrase is needed for | |
1211 | * it, whereas identity files may require passphrases. | |
1212 | */ | |
1213 | if (try_agent_authentication()) | |
1214 | goto success; | |
1215 | ||
1216 | /* Try RSA authentication for each identity. */ | |
1217 | for (i = 0; i < options.num_identity_files; i++) | |
1218 | if (options.identity_keys[i] != NULL && | |
1219 | options.identity_keys[i]->type == KEY_RSA1 && | |
1220 | try_rsa_authentication(i)) | |
1221 | goto success; | |
1222 | } | |
1223 | /* Try challenge response authentication if the server supports it. */ | |
1224 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && | |
1225 | options.challenge_response_authentication && !options.batch_mode) { | |
1226 | if (try_challenge_response_authentication()) | |
1227 | goto success; | |
1228 | } | |
1229 | /* Try password authentication if the server supports it. */ | |
1230 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1231 | options.password_authentication && !options.batch_mode) { | |
1232 | char prompt[80]; | |
1233 | ||
1234 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", | |
1235 | server_user, host); | |
1236 | if (try_password_authentication(prompt)) | |
1237 | goto success; | |
1238 | } | |
1239 | /* All authentication methods have failed. Exit with an error message. */ | |
1240 | fatal("Permission denied."); | |
1241 | /* NOTREACHED */ | |
1242 | ||
1243 | success: | |
1244 | #ifdef KRB5 | |
1245 | /* Try Kerberos v5 TGT passing. */ | |
1246 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1247 | options.kerberos_tgt_passing && context && auth_context) { | |
1248 | if (options.cipher == SSH_CIPHER_NONE) | |
1249 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1250 | send_krb5_tgt(context, auth_context); | |
1251 | } | |
1252 | if (auth_context) | |
1253 | krb5_auth_con_free(context, auth_context); | |
1254 | if (context) | |
1255 | krb5_free_context(context); | |
1256 | #endif | |
1257 | ||
1258 | #ifdef AFS | |
1259 | /* Try Kerberos v4 TGT passing if the server supports it. */ | |
1260 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1261 | options.kerberos_tgt_passing) { | |
1262 | if (options.cipher == SSH_CIPHER_NONE) | |
1263 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1264 | send_krb4_tgt(); | |
1265 | } | |
1266 | /* Try AFS token passing if the server supports it. */ | |
1267 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1268 | options.afs_token_passing && k_hasafs()) { | |
1269 | if (options.cipher == SSH_CIPHER_NONE) | |
1270 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1271 | send_afs_tokens(); | |
1272 | } | |
1273 | #endif /* AFS */ | |
1274 | ||
1275 | /* give the compiler something to do for success: */ | |
1276 | #if !defined(KRB5) && !defined(AFS) | |
1277 | ; | |
1278 | #endif | |
1279 | } |