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a306f2dd | 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 | |
a306f2dd | 5 | * Code to connect to a remote host, and to perform the client side of the |
6 | * login (authentication) dialog. | |
7 | * | |
bcbf86ec | 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". | |
a306f2dd | 13 | */ |
14 | ||
15 | #include "includes.h" | |
ced49be2 | 16 | RCSID("$OpenBSD: sshconnect1.c,v 1.37 2001/06/26 16:15:24 dugsong Exp $"); |
a306f2dd | 17 | |
18 | #include <openssl/bn.h> | |
a306f2dd | 19 | #include <openssl/evp.h> |
20 | ||
42f11eb2 | 21 | #ifdef KRB4 |
22 | #include <krb.h> | |
42f11eb2 | 23 | #endif |
ced49be2 | 24 | #ifdef KRB5 |
25 | #include <krb5.h> | |
26 | #endif | |
42f11eb2 | 27 | #ifdef AFS |
28 | #include <kafs.h> | |
53a24016 | 29 | #include "radix.h" |
42f11eb2 | 30 | #endif |
31 | ||
32 | #include "ssh.h" | |
33 | #include "ssh1.h" | |
a306f2dd | 34 | #include "xmalloc.h" |
35 | #include "rsa.h" | |
a306f2dd | 36 | #include "buffer.h" |
37 | #include "packet.h" | |
a306f2dd | 38 | #include "mpaux.h" |
39 | #include "uidswap.h" | |
42f11eb2 | 40 | #include "log.h" |
a306f2dd | 41 | #include "readconf.h" |
42 | #include "key.h" | |
4c8722d9 | 43 | #include "authfd.h" |
a306f2dd | 44 | #include "sshconnect.h" |
45 | #include "authfile.h" | |
42f11eb2 | 46 | #include "readpass.h" |
47 | #include "cipher.h" | |
48 | #include "canohost.h" | |
ced49be2 | 49 | #include "auth.h" |
a306f2dd | 50 | |
51 | /* Session id for the current session. */ | |
1e3b8b07 | 52 | u_char session_id[16]; |
53 | u_int supported_authentications = 0; | |
a306f2dd | 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 | */ | |
396c147e | 62 | static int |
5ca51e19 | 63 | try_agent_authentication(void) |
a306f2dd | 64 | { |
2e73a022 | 65 | int type; |
a306f2dd | 66 | char *comment; |
67 | AuthenticationConnection *auth; | |
1e3b8b07 | 68 | u_char response[16]; |
69 | u_int i; | |
2e73a022 | 70 | int plen, clen; |
71 | Key *key; | |
72 | BIGNUM *challenge; | |
a306f2dd | 73 | |
74 | /* Get connection to the agent. */ | |
75 | auth = ssh_get_authentication_connection(); | |
76 | if (!auth) | |
77 | return 0; | |
78 | ||
a306f2dd | 79 | challenge = BN_new(); |
80 | ||
81 | /* Loop through identities served by the agent. */ | |
2e73a022 | 82 | for (key = ssh_get_first_identity(auth, &comment, 1); |
83 | key != NULL; | |
84 | key = ssh_get_next_identity(auth, &comment, 1)) { | |
a306f2dd | 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); | |
2e73a022 | 92 | packet_put_bignum(key->rsa->n); |
a306f2dd | 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."); | |
2e73a022 | 103 | key_free(key); |
a306f2dd | 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. */ | |
2e73a022 | 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 | */ | |
a306f2dd | 124 | log("Authentication agent failed to decrypt challenge."); |
125 | memset(response, 0, sizeof(response)); | |
126 | } | |
2e73a022 | 127 | key_free(key); |
a306f2dd | 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) { | |
eea39c02 | 142 | ssh_close_authentication_connection(auth); |
a306f2dd | 143 | BN_clear_free(challenge); |
2e73a022 | 144 | debug("RSA authentication accepted by server."); |
a306f2dd | 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 | } | |
eea39c02 | 152 | ssh_close_authentication_connection(auth); |
a306f2dd | 153 | BN_clear_free(challenge); |
a306f2dd | 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 | */ | |
396c147e | 162 | static void |
a306f2dd | 163 | respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv) |
164 | { | |
1e3b8b07 | 165 | u_char buf[32], response[16]; |
a306f2dd | 166 | MD5_CTX md; |
167 | int i, len; | |
168 | ||
169 | /* Decrypt the challenge using the private key. */ | |
46aa2d1f | 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"); | |
a306f2dd | 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)) | |
46aa2d1f | 179 | packet_disconnect( |
180 | "respond_to_rsa_challenge: bad challenge length %d", len); | |
a306f2dd | 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 | */ | |
396c147e | 207 | static int |
a306f2dd | 208 | try_rsa_authentication(const char *authfile) |
209 | { | |
210 | BIGNUM *challenge; | |
ce404659 | 211 | Key *public, *private; |
212 | char buf[300], *passphrase, *comment; | |
213 | int i, type, quit, plen, clen; | |
a306f2dd | 214 | |
215 | /* Try to load identification for the authentication key. */ | |
aeaa3d9e | 216 | /* XXKEYLOAD */ |
217 | public = key_load_public_type(KEY_RSA1, authfile, &comment); | |
218 | if (public == NULL) { | |
a306f2dd | 219 | /* Could not load it. Fail. */ |
220 | return 0; | |
221 | } | |
222 | debug("Trying RSA authentication with key '%.100s'", comment); | |
223 | ||
224 | /* Tell the server that we are willing to authenticate using this key. */ | |
225 | packet_start(SSH_CMSG_AUTH_RSA); | |
226 | packet_put_bignum(public->rsa->n); | |
227 | packet_send(); | |
228 | packet_write_wait(); | |
229 | ||
230 | /* We no longer need the public key. */ | |
231 | key_free(public); | |
232 | ||
233 | /* Wait for server's response. */ | |
234 | type = packet_read(&plen); | |
235 | ||
236 | /* | |
237 | * The server responds with failure if it doesn\'t like our key or | |
238 | * doesn\'t support RSA authentication. | |
239 | */ | |
240 | if (type == SSH_SMSG_FAILURE) { | |
241 | debug("Server refused our key."); | |
242 | xfree(comment); | |
243 | return 0; | |
244 | } | |
245 | /* Otherwise, the server should respond with a challenge. */ | |
246 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
247 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
248 | ||
249 | /* Get the challenge from the packet. */ | |
250 | challenge = BN_new(); | |
251 | packet_get_bignum(challenge, &clen); | |
252 | ||
253 | packet_integrity_check(plen, clen, type); | |
254 | ||
255 | debug("Received RSA challenge from server."); | |
256 | ||
a306f2dd | 257 | /* |
258 | * Load the private key. Try first with empty passphrase; if it | |
259 | * fails, ask for a passphrase. | |
260 | */ | |
aeaa3d9e | 261 | private = key_load_private_type(KEY_RSA1, authfile, "", NULL); |
ce404659 | 262 | if (private == NULL && !options.batch_mode) { |
263 | snprintf(buf, sizeof(buf), | |
264 | "Enter passphrase for RSA key '%.100s': ", comment); | |
265 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
a306f2dd | 266 | passphrase = read_passphrase(buf, 0); |
ce404659 | 267 | if (strcmp(passphrase, "") != 0) { |
268 | private = key_load_private_type(KEY_RSA1, | |
269 | authfile, passphrase, NULL); | |
270 | quit = 0; | |
271 | } else { | |
272 | debug2("no passphrase given, try next key"); | |
273 | quit = 1; | |
274 | } | |
a306f2dd | 275 | memset(passphrase, 0, strlen(passphrase)); |
276 | xfree(passphrase); | |
ce404659 | 277 | if (private != NULL || quit) |
278 | break; | |
279 | debug2("bad passphrase given, try again..."); | |
a306f2dd | 280 | } |
a306f2dd | 281 | } |
282 | /* We no longer need the comment. */ | |
283 | xfree(comment); | |
284 | ||
ce404659 | 285 | if (private == NULL) { |
286 | if (!options.batch_mode) | |
287 | error("Bad passphrase."); | |
288 | ||
289 | /* Send a dummy response packet to avoid protocol error. */ | |
290 | packet_start(SSH_CMSG_AUTH_RSA_RESPONSE); | |
291 | for (i = 0; i < 16; i++) | |
292 | packet_put_char(0); | |
293 | packet_send(); | |
294 | packet_write_wait(); | |
295 | ||
296 | /* Expect the server to reject it... */ | |
297 | packet_read_expect(&plen, SSH_SMSG_FAILURE); | |
298 | BN_clear_free(challenge); | |
299 | return 0; | |
300 | } | |
301 | ||
a306f2dd | 302 | /* Compute and send a response to the challenge. */ |
303 | respond_to_rsa_challenge(challenge, private->rsa); | |
304 | ||
305 | /* Destroy the private key. */ | |
306 | key_free(private); | |
307 | ||
308 | /* We no longer need the challenge. */ | |
309 | BN_clear_free(challenge); | |
310 | ||
311 | /* Wait for response from the server. */ | |
312 | type = packet_read(&plen); | |
313 | if (type == SSH_SMSG_SUCCESS) { | |
314 | debug("RSA authentication accepted by server."); | |
315 | return 1; | |
316 | } | |
317 | if (type != SSH_SMSG_FAILURE) | |
318 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
319 | debug("RSA authentication refused."); | |
320 | return 0; | |
321 | } | |
322 | ||
323 | /* | |
324 | * Tries to authenticate the user using combined rhosts or /etc/hosts.equiv | |
325 | * authentication and RSA host authentication. | |
326 | */ | |
396c147e | 327 | static int |
aeaa3d9e | 328 | try_rhosts_rsa_authentication(const char *local_user, Key * host_key) |
a306f2dd | 329 | { |
330 | int type; | |
331 | BIGNUM *challenge; | |
332 | int plen, clen; | |
333 | ||
334 | debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication."); | |
335 | ||
336 | /* Tell the server that we are willing to authenticate using this key. */ | |
337 | packet_start(SSH_CMSG_AUTH_RHOSTS_RSA); | |
449c5ba5 | 338 | packet_put_cstring(local_user); |
aeaa3d9e | 339 | packet_put_int(BN_num_bits(host_key->rsa->n)); |
340 | packet_put_bignum(host_key->rsa->e); | |
341 | packet_put_bignum(host_key->rsa->n); | |
a306f2dd | 342 | packet_send(); |
343 | packet_write_wait(); | |
344 | ||
345 | /* Wait for server's response. */ | |
346 | type = packet_read(&plen); | |
347 | ||
348 | /* The server responds with failure if it doesn't admit our | |
349 | .rhosts authentication or doesn't know our host key. */ | |
350 | if (type == SSH_SMSG_FAILURE) { | |
351 | debug("Server refused our rhosts authentication or host key."); | |
352 | return 0; | |
353 | } | |
354 | /* Otherwise, the server should respond with a challenge. */ | |
355 | if (type != SSH_SMSG_AUTH_RSA_CHALLENGE) | |
356 | packet_disconnect("Protocol error during RSA authentication: %d", type); | |
357 | ||
358 | /* Get the challenge from the packet. */ | |
359 | challenge = BN_new(); | |
360 | packet_get_bignum(challenge, &clen); | |
361 | ||
362 | packet_integrity_check(plen, clen, type); | |
363 | ||
364 | debug("Received RSA challenge for host key from server."); | |
365 | ||
366 | /* Compute a response to the challenge. */ | |
aeaa3d9e | 367 | respond_to_rsa_challenge(challenge, host_key->rsa); |
a306f2dd | 368 | |
369 | /* We no longer need the challenge. */ | |
370 | BN_clear_free(challenge); | |
371 | ||
372 | /* Wait for response from the server. */ | |
373 | type = packet_read(&plen); | |
374 | if (type == SSH_SMSG_SUCCESS) { | |
375 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server."); | |
376 | return 1; | |
377 | } | |
378 | if (type != SSH_SMSG_FAILURE) | |
379 | packet_disconnect("Protocol error waiting RSA auth response: %d", type); | |
380 | debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused."); | |
381 | return 0; | |
382 | } | |
383 | ||
384 | #ifdef KRB4 | |
396c147e | 385 | static int |
ced49be2 | 386 | try_krb4_authentication(void) |
a306f2dd | 387 | { |
388 | KTEXT_ST auth; /* Kerberos data */ | |
389 | char *reply; | |
390 | char inst[INST_SZ]; | |
391 | char *realm; | |
392 | CREDENTIALS cred; | |
393 | int r, type, plen; | |
394 | socklen_t slen; | |
395 | Key_schedule schedule; | |
396 | u_long checksum, cksum; | |
397 | MSG_DAT msg_data; | |
398 | struct sockaddr_in local, foreign; | |
399 | struct stat st; | |
400 | ||
401 | /* Don't do anything if we don't have any tickets. */ | |
402 | if (stat(tkt_string(), &st) < 0) | |
403 | return 0; | |
ced49be2 | 404 | |
405 | strlcpy(inst, (char *)krb_get_phost(get_canonical_hostname(1)), | |
406 | INST_SZ); | |
407 | ||
408 | realm = (char *)krb_realmofhost(get_canonical_hostname(1)); | |
a306f2dd | 409 | if (!realm) { |
ced49be2 | 410 | debug("Kerberos v4: no realm for %s", get_canonical_hostname(1)); |
a306f2dd | 411 | return 0; |
412 | } | |
413 | /* This can really be anything. */ | |
ced49be2 | 414 | checksum = (u_long)getpid(); |
415 | ||
a306f2dd | 416 | r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum); |
417 | if (r != KSUCCESS) { | |
ced49be2 | 418 | debug("Kerberos v4 krb_mk_req failed: %s", krb_err_txt[r]); |
a306f2dd | 419 | return 0; |
420 | } | |
421 | /* Get session key to decrypt the server's reply with. */ | |
422 | r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred); | |
423 | if (r != KSUCCESS) { | |
424 | debug("get_cred failed: %s", krb_err_txt[r]); | |
425 | return 0; | |
426 | } | |
427 | des_key_sched((des_cblock *) cred.session, schedule); | |
ced49be2 | 428 | |
a306f2dd | 429 | /* Send authentication info to server. */ |
430 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
431 | packet_put_string((char *) auth.dat, auth.length); | |
432 | packet_send(); | |
433 | packet_write_wait(); | |
ced49be2 | 434 | |
a306f2dd | 435 | /* Zero the buffer. */ |
436 | (void) memset(auth.dat, 0, MAX_KTXT_LEN); | |
ced49be2 | 437 | |
a306f2dd | 438 | slen = sizeof(local); |
439 | memset(&local, 0, sizeof(local)); | |
440 | if (getsockname(packet_get_connection_in(), | |
ced49be2 | 441 | (struct sockaddr *)&local, &slen) < 0) |
a306f2dd | 442 | debug("getsockname failed: %s", strerror(errno)); |
ced49be2 | 443 | |
a306f2dd | 444 | slen = sizeof(foreign); |
445 | memset(&foreign, 0, sizeof(foreign)); | |
446 | if (getpeername(packet_get_connection_in(), | |
ced49be2 | 447 | (struct sockaddr *)&foreign, &slen) < 0) { |
a306f2dd | 448 | debug("getpeername failed: %s", strerror(errno)); |
449 | fatal_cleanup(); | |
450 | } | |
451 | /* Get server reply. */ | |
452 | type = packet_read(&plen); | |
453 | switch (type) { | |
454 | case SSH_SMSG_FAILURE: | |
455 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
ced49be2 | 456 | debug("Kerberos v4 authentication failed."); |
a306f2dd | 457 | return 0; |
458 | break; | |
ced49be2 | 459 | |
a306f2dd | 460 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: |
461 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
ced49be2 | 462 | debug("Kerberos v4 authentication accepted."); |
463 | ||
a306f2dd | 464 | /* Get server's response. */ |
1e3b8b07 | 465 | reply = packet_get_string((u_int *) &auth.length); |
a306f2dd | 466 | memcpy(auth.dat, reply, auth.length); |
467 | xfree(reply); | |
ced49be2 | 468 | |
a306f2dd | 469 | packet_integrity_check(plen, 4 + auth.length, type); |
ced49be2 | 470 | |
a306f2dd | 471 | /* |
472 | * If his response isn't properly encrypted with the session | |
473 | * key, and the decrypted checksum fails to match, he's | |
474 | * bogus. Bail out. | |
475 | */ | |
476 | r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session, | |
ced49be2 | 477 | &foreign, &local, &msg_data); |
a306f2dd | 478 | if (r != KSUCCESS) { |
ced49be2 | 479 | debug("Kerberos v4 krb_rd_priv failed: %s", |
480 | krb_err_txt[r]); | |
481 | packet_disconnect("Kerberos v4 challenge failed!"); | |
a306f2dd | 482 | } |
483 | /* Fetch the (incremented) checksum that we supplied in the request. */ | |
ced49be2 | 484 | memcpy((char *)&cksum, (char *)msg_data.app_data, |
485 | sizeof(cksum)); | |
a306f2dd | 486 | cksum = ntohl(cksum); |
ced49be2 | 487 | |
a306f2dd | 488 | /* If it matches, we're golden. */ |
489 | if (cksum == checksum + 1) { | |
ced49be2 | 490 | debug("Kerberos v4 challenge successful."); |
a306f2dd | 491 | return 1; |
492 | } else | |
ced49be2 | 493 | packet_disconnect("Kerberos v4 challenge failed!"); |
a306f2dd | 494 | break; |
ced49be2 | 495 | |
a306f2dd | 496 | default: |
ced49be2 | 497 | packet_disconnect("Protocol error on Kerberos v4 response: %d", type); |
a306f2dd | 498 | } |
499 | return 0; | |
500 | } | |
501 | ||
502 | #endif /* KRB4 */ | |
503 | ||
ced49be2 | 504 | #ifdef KRB5 |
396c147e | 505 | static int |
ced49be2 | 506 | try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context) |
507 | { | |
508 | krb5_error_code problem; | |
509 | const char *tkfile; | |
510 | struct stat buf; | |
511 | krb5_ccache ccache = NULL; | |
512 | const char *remotehost; | |
513 | krb5_data ap; | |
514 | int type, payload_len; | |
515 | krb5_ap_rep_enc_part *reply = NULL; | |
516 | int ret; | |
517 | ||
518 | memset(&ap, 0, sizeof(ap)); | |
519 | ||
520 | problem = krb5_init_context(context); | |
521 | if (problem) { | |
522 | debug("Kerberos v5: krb5_init_context failed"); | |
523 | ret = 0; | |
524 | goto out; | |
525 | } | |
526 | ||
527 | tkfile = krb5_cc_default_name(*context); | |
528 | if (strncmp(tkfile, "FILE:", 5) == 0) | |
529 | tkfile += 5; | |
530 | ||
531 | if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) { | |
532 | debug("Kerberos v5: could not get default ccache (permission denied)."); | |
533 | ret = 0; | |
534 | goto out; | |
535 | } | |
536 | ||
537 | problem = krb5_cc_default(*context, &ccache); | |
538 | if (problem) { | |
539 | debug("Kerberos v5: krb5_cc_default failed: %s", | |
540 | krb5_get_err_text(*context, problem)); | |
541 | ret = 0; | |
542 | goto out; | |
543 | } | |
544 | ||
545 | remotehost = get_canonical_hostname(1); | |
546 | ||
547 | problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED, | |
548 | "host", remotehost, NULL, ccache, &ap); | |
549 | if (problem) { | |
550 | debug("Kerberos v5: krb5_mk_req failed: %s", | |
551 | krb5_get_err_text(*context, problem)); | |
552 | ret = 0; | |
553 | goto out; | |
554 | } | |
555 | ||
556 | packet_start(SSH_CMSG_AUTH_KERBEROS); | |
557 | packet_put_string((char *) ap.data, ap.length); | |
558 | packet_send(); | |
559 | packet_write_wait(); | |
560 | ||
561 | xfree(ap.data); | |
562 | ap.length = 0; | |
563 | ||
564 | type = packet_read(&payload_len); | |
565 | switch (type) { | |
566 | case SSH_SMSG_FAILURE: | |
567 | /* Should really be SSH_SMSG_AUTH_KERBEROS_FAILURE */ | |
568 | debug("Kerberos v5 authentication failed."); | |
569 | ret = 0; | |
570 | break; | |
571 | ||
572 | case SSH_SMSG_AUTH_KERBEROS_RESPONSE: | |
573 | /* SSH_SMSG_AUTH_KERBEROS_SUCCESS */ | |
574 | debug("Kerberos v5 authentication accepted."); | |
575 | ||
576 | /* Get server's response. */ | |
577 | ap.data = packet_get_string((unsigned int *) &ap.length); | |
578 | ||
579 | packet_integrity_check(payload_len, 4 + ap.length, type); | |
580 | /* XXX je to dobre? */ | |
581 | ||
582 | problem = krb5_rd_rep(*context, *auth_context, &ap, &reply); | |
583 | if (problem) { | |
584 | ret = 0; | |
585 | } | |
586 | ret = 1; | |
587 | break; | |
588 | ||
589 | default: | |
590 | packet_disconnect("Protocol error on Kerberos v5 response: %d", | |
591 | type); | |
592 | ret = 0; | |
593 | break; | |
594 | ||
595 | } | |
596 | ||
597 | out: | |
598 | if (ccache != NULL) | |
599 | krb5_cc_close(*context, ccache); | |
600 | if (reply != NULL) | |
601 | krb5_free_ap_rep_enc_part(*context, reply); | |
602 | if (ap.length > 0) | |
603 | krb5_data_free(&ap); | |
604 | ||
605 | return (ret); | |
606 | } | |
607 | ||
608 | static void | |
609 | send_krb5_tgt(krb5_context context, krb5_auth_context auth_context) | |
610 | { | |
611 | int fd, type, payload_len; | |
612 | krb5_error_code problem; | |
613 | krb5_data outbuf; | |
614 | krb5_ccache ccache = NULL; | |
615 | krb5_creds creds; | |
616 | krb5_kdc_flags flags; | |
617 | const char *remotehost; | |
618 | ||
619 | memset(&creds, 0, sizeof(creds)); | |
620 | memset(&outbuf, 0, sizeof(outbuf)); | |
621 | ||
622 | fd = packet_get_connection_in(); | |
623 | ||
624 | problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd); | |
625 | if (problem) | |
626 | goto out; | |
627 | ||
628 | problem = krb5_cc_default(context, &ccache); | |
629 | if (problem) | |
630 | goto out; | |
631 | ||
632 | problem = krb5_cc_get_principal(context, ccache, &creds.client); | |
633 | if (problem) | |
634 | goto out; | |
635 | ||
636 | problem = krb5_build_principal(context, &creds.server, | |
637 | strlen(creds.client->realm), creds.client->realm, | |
638 | "krbtgt", creds.client->realm, NULL); | |
639 | if (problem) | |
640 | goto out; | |
641 | ||
642 | creds.times.endtime = 0; | |
643 | ||
644 | flags.i = 0; | |
645 | flags.b.forwarded = 1; | |
646 | flags.b.forwardable = krb5_config_get_bool(context, NULL, | |
647 | "libdefaults", "forwardable", NULL); | |
648 | ||
649 | remotehost = get_canonical_hostname(1); | |
650 | ||
651 | problem = krb5_get_forwarded_creds(context, auth_context, | |
652 | ccache, flags.i, remotehost, &creds, &outbuf); | |
653 | if (problem) | |
654 | goto out; | |
655 | ||
656 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); | |
657 | packet_put_string((char *)outbuf.data, outbuf.length); | |
658 | packet_send(); | |
659 | packet_write_wait(); | |
660 | ||
661 | type = packet_read(&payload_len); | |
662 | ||
663 | if (type == SSH_SMSG_SUCCESS) { | |
664 | char *pname; | |
665 | ||
666 | krb5_unparse_name(context, creds.client, &pname); | |
667 | debug("Kerberos v5 TGT forwarded (%s).", pname); | |
668 | xfree(pname); | |
669 | } else | |
670 | debug("Kerberos v5 TGT forwarding failed."); | |
671 | ||
672 | return; | |
673 | ||
674 | out: | |
675 | if (problem) | |
676 | debug("Kerberos v5 TGT forwarding failed: %s", | |
677 | krb5_get_err_text(context, problem)); | |
678 | if (creds.client) | |
679 | krb5_free_principal(context, creds.client); | |
680 | if (creds.server) | |
681 | krb5_free_principal(context, creds.server); | |
682 | if (ccache) | |
683 | krb5_cc_close(context, ccache); | |
684 | if (outbuf.data) | |
685 | xfree(outbuf.data); | |
686 | } | |
687 | #endif /* KRB5 */ | |
688 | ||
689 | #ifdef AFS | |
690 | static void | |
691 | send_krb4_tgt(void) | |
a306f2dd | 692 | { |
693 | CREDENTIALS *creds; | |
a306f2dd | 694 | struct stat st; |
ced49be2 | 695 | char buffer[4096], pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ]; |
696 | int problem, type, len; | |
697 | ||
a306f2dd | 698 | /* Don't do anything if we don't have any tickets. */ |
699 | if (stat(tkt_string(), &st) < 0) | |
ced49be2 | 700 | return; |
701 | ||
a306f2dd | 702 | creds = xmalloc(sizeof(*creds)); |
ced49be2 | 703 | |
704 | problem = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm); | |
705 | if (problem) | |
706 | goto out; | |
707 | ||
708 | problem = krb_get_cred("krbtgt", prealm, prealm, creds); | |
709 | if (problem) | |
710 | goto out; | |
711 | ||
a306f2dd | 712 | if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) { |
ced49be2 | 713 | problem = RD_AP_EXP; |
714 | goto out; | |
a306f2dd | 715 | } |
ced49be2 | 716 | creds_to_radix(creds, (u_char *)buffer, sizeof(buffer)); |
717 | ||
a306f2dd | 718 | packet_start(SSH_CMSG_HAVE_KERBEROS_TGT); |
449c5ba5 | 719 | packet_put_cstring(buffer); |
a306f2dd | 720 | packet_send(); |
721 | packet_write_wait(); | |
ced49be2 | 722 | |
723 | type = packet_read(&len); | |
724 | ||
725 | if (type == SSH_SMSG_SUCCESS) | |
726 | debug("Kerberos v4 TGT forwarded (%s%s%s@%s).", | |
727 | creds->pname, creds->pinst[0] ? "." : "", | |
728 | creds->pinst, creds->realm); | |
729 | else | |
730 | debug("Kerberos v4 TGT rejected."); | |
731 | ||
732 | xfree(creds); | |
733 | return; | |
734 | ||
735 | out: | |
736 | debug("Kerberos v4 TGT passing failed: %s", krb_err_txt[problem]); | |
737 | xfree(creds); | |
a306f2dd | 738 | } |
739 | ||
396c147e | 740 | static void |
a306f2dd | 741 | send_afs_tokens(void) |
742 | { | |
743 | CREDENTIALS creds; | |
744 | struct ViceIoctl parms; | |
745 | struct ClearToken ct; | |
ced49be2 | 746 | int i, type, len; |
a306f2dd | 747 | char buf[2048], *p, *server_cell; |
748 | char buffer[8192]; | |
ced49be2 | 749 | |
a306f2dd | 750 | /* Move over ktc_GetToken, here's something leaner. */ |
751 | for (i = 0; i < 100; i++) { /* just in case */ | |
752 | parms.in = (char *) &i; | |
753 | parms.in_size = sizeof(i); | |
754 | parms.out = buf; | |
755 | parms.out_size = sizeof(buf); | |
756 | if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0) | |
757 | break; | |
758 | p = buf; | |
ced49be2 | 759 | |
a306f2dd | 760 | /* Get secret token. */ |
1e3b8b07 | 761 | memcpy(&creds.ticket_st.length, p, sizeof(u_int)); |
a306f2dd | 762 | if (creds.ticket_st.length > MAX_KTXT_LEN) |
763 | break; | |
1e3b8b07 | 764 | p += sizeof(u_int); |
a306f2dd | 765 | memcpy(creds.ticket_st.dat, p, creds.ticket_st.length); |
766 | p += creds.ticket_st.length; | |
ced49be2 | 767 | |
a306f2dd | 768 | /* Get clear token. */ |
769 | memcpy(&len, p, sizeof(len)); | |
770 | if (len != sizeof(struct ClearToken)) | |
771 | break; | |
772 | p += sizeof(len); | |
773 | memcpy(&ct, p, len); | |
774 | p += len; | |
775 | p += sizeof(len); /* primary flag */ | |
776 | server_cell = p; | |
ced49be2 | 777 | |
a306f2dd | 778 | /* Flesh out our credentials. */ |
ced49be2 | 779 | strlcpy(creds.service, "afs", sizeof(creds.service)); |
a306f2dd | 780 | creds.instance[0] = '\0'; |
781 | strlcpy(creds.realm, server_cell, REALM_SZ); | |
782 | memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ); | |
783 | creds.issue_date = ct.BeginTimestamp; | |
ced49be2 | 784 | creds.lifetime = krb_time_to_life(creds.issue_date, |
785 | ct.EndTimestamp); | |
a306f2dd | 786 | creds.kvno = ct.AuthHandle; |
787 | snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId); | |
788 | creds.pinst[0] = '\0'; | |
ced49be2 | 789 | |
a306f2dd | 790 | /* Encode token, ship it off. */ |
ced49be2 | 791 | if (creds_to_radix(&creds, (u_char *)buffer, |
792 | sizeof(buffer)) <= 0) | |
a306f2dd | 793 | break; |
794 | packet_start(SSH_CMSG_HAVE_AFS_TOKEN); | |
449c5ba5 | 795 | packet_put_cstring(buffer); |
a306f2dd | 796 | packet_send(); |
797 | packet_write_wait(); | |
798 | ||
799 | /* Roger, Roger. Clearance, Clarence. What's your vector, | |
800 | Victor? */ | |
ced49be2 | 801 | type = packet_read(&len); |
802 | ||
a306f2dd | 803 | if (type == SSH_SMSG_FAILURE) |
804 | debug("AFS token for cell %s rejected.", server_cell); | |
805 | else if (type != SSH_SMSG_SUCCESS) | |
806 | packet_disconnect("Protocol error on AFS token response: %d", type); | |
807 | } | |
808 | } | |
809 | ||
810 | #endif /* AFS */ | |
811 | ||
812 | /* | |
813 | * Tries to authenticate with any string-based challenge/response system. | |
814 | * Note that the client code is not tied to s/key or TIS. | |
815 | */ | |
396c147e | 816 | static int |
5ba55ada | 817 | try_challenge_response_authentication(void) |
a306f2dd | 818 | { |
819 | int type, i; | |
820 | int payload_len; | |
1e3b8b07 | 821 | u_int clen; |
e3a70753 | 822 | char prompt[1024]; |
a306f2dd | 823 | char *challenge, *response; |
ced49be2 | 824 | |
d464095c | 825 | debug("Doing challenge reponse authentication."); |
ced49be2 | 826 | |
a306f2dd | 827 | for (i = 0; i < options.number_of_password_prompts; i++) { |
e3a70753 | 828 | /* request a challenge */ |
829 | packet_start(SSH_CMSG_AUTH_TIS); | |
830 | packet_send(); | |
831 | packet_write_wait(); | |
832 | ||
833 | type = packet_read(&payload_len); | |
834 | if (type != SSH_SMSG_FAILURE && | |
835 | type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
836 | packet_disconnect("Protocol error: got %d in response " | |
d464095c | 837 | "to SSH_CMSG_AUTH_TIS", type); |
e3a70753 | 838 | } |
839 | if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) { | |
d464095c | 840 | debug("No challenge."); |
e3a70753 | 841 | return 0; |
842 | } | |
843 | challenge = packet_get_string(&clen); | |
844 | packet_integrity_check(payload_len, (4 + clen), type); | |
59c97189 | 845 | snprintf(prompt, sizeof prompt, "%s%s", challenge, |
846 | strchr(challenge, '\n') ? "" : "\nResponse: "); | |
e3a70753 | 847 | xfree(challenge); |
a306f2dd | 848 | if (i != 0) |
849 | error("Permission denied, please try again."); | |
e3a70753 | 850 | if (options.cipher == SSH_CIPHER_NONE) |
851 | log("WARNING: Encryption is disabled! " | |
852 | "Reponse will be transmitted in clear text."); | |
853 | response = read_passphrase(prompt, 0); | |
854 | if (strcmp(response, "") == 0) { | |
855 | xfree(response); | |
856 | break; | |
857 | } | |
a306f2dd | 858 | packet_start(SSH_CMSG_AUTH_TIS_RESPONSE); |
0ae4fe1d | 859 | ssh_put_password(response); |
a306f2dd | 860 | memset(response, 0, strlen(response)); |
861 | xfree(response); | |
862 | packet_send(); | |
863 | packet_write_wait(); | |
864 | type = packet_read(&payload_len); | |
865 | if (type == SSH_SMSG_SUCCESS) | |
866 | return 1; | |
867 | if (type != SSH_SMSG_FAILURE) | |
868 | packet_disconnect("Protocol error: got %d in response " | |
d464095c | 869 | "to SSH_CMSG_AUTH_TIS_RESPONSE", type); |
a306f2dd | 870 | } |
871 | /* failure */ | |
872 | return 0; | |
873 | } | |
874 | ||
875 | /* | |
876 | * Tries to authenticate with plain passwd authentication. | |
877 | */ | |
396c147e | 878 | static int |
a306f2dd | 879 | try_password_authentication(char *prompt) |
880 | { | |
881 | int type, i, payload_len; | |
882 | char *password; | |
883 | ||
884 | debug("Doing password authentication."); | |
885 | if (options.cipher == SSH_CIPHER_NONE) | |
886 | log("WARNING: Encryption is disabled! Password will be transmitted in clear text."); | |
887 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
888 | if (i != 0) | |
889 | error("Permission denied, please try again."); | |
890 | password = read_passphrase(prompt, 0); | |
891 | packet_start(SSH_CMSG_AUTH_PASSWORD); | |
0ae4fe1d | 892 | ssh_put_password(password); |
a306f2dd | 893 | memset(password, 0, strlen(password)); |
894 | xfree(password); | |
895 | packet_send(); | |
896 | packet_write_wait(); | |
897 | ||
898 | type = packet_read(&payload_len); | |
899 | if (type == SSH_SMSG_SUCCESS) | |
900 | return 1; | |
901 | if (type != SSH_SMSG_FAILURE) | |
902 | packet_disconnect("Protocol error: got %d in response to passwd auth", type); | |
903 | } | |
904 | /* failure */ | |
905 | return 0; | |
906 | } | |
907 | ||
908 | /* | |
909 | * SSH1 key exchange | |
910 | */ | |
911 | void | |
912 | ssh_kex(char *host, struct sockaddr *hostaddr) | |
913 | { | |
914 | int i; | |
915 | BIGNUM *key; | |
916 | RSA *host_key; | |
917 | RSA *public_key; | |
918 | Key k; | |
919 | int bits, rbits; | |
920 | int ssh_cipher_default = SSH_CIPHER_3DES; | |
1e3b8b07 | 921 | u_char session_key[SSH_SESSION_KEY_LENGTH]; |
922 | u_char cookie[8]; | |
923 | u_int supported_ciphers; | |
924 | u_int server_flags, client_flags; | |
a306f2dd | 925 | int payload_len, clen, sum_len = 0; |
926 | u_int32_t rand = 0; | |
927 | ||
928 | debug("Waiting for server public key."); | |
929 | ||
930 | /* Wait for a public key packet from the server. */ | |
931 | packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY); | |
932 | ||
933 | /* Get cookie from the packet. */ | |
934 | for (i = 0; i < 8; i++) | |
935 | cookie[i] = packet_get_char(); | |
936 | ||
937 | /* Get the public key. */ | |
938 | public_key = RSA_new(); | |
939 | bits = packet_get_int();/* bits */ | |
940 | public_key->e = BN_new(); | |
941 | packet_get_bignum(public_key->e, &clen); | |
942 | sum_len += clen; | |
943 | public_key->n = BN_new(); | |
944 | packet_get_bignum(public_key->n, &clen); | |
945 | sum_len += clen; | |
946 | ||
947 | rbits = BN_num_bits(public_key->n); | |
948 | if (bits != rbits) { | |
949 | log("Warning: Server lies about size of server public key: " | |
950 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
951 | log("Warning: This may be due to an old implementation of ssh."); | |
952 | } | |
953 | /* Get the host key. */ | |
954 | host_key = RSA_new(); | |
955 | bits = packet_get_int();/* bits */ | |
956 | host_key->e = BN_new(); | |
957 | packet_get_bignum(host_key->e, &clen); | |
958 | sum_len += clen; | |
959 | host_key->n = BN_new(); | |
960 | packet_get_bignum(host_key->n, &clen); | |
961 | sum_len += clen; | |
962 | ||
963 | rbits = BN_num_bits(host_key->n); | |
964 | if (bits != rbits) { | |
965 | log("Warning: Server lies about size of server host key: " | |
966 | "actual size is %d bits vs. announced %d.", rbits, bits); | |
967 | log("Warning: This may be due to an old implementation of ssh."); | |
968 | } | |
969 | ||
970 | /* Get protocol flags. */ | |
971 | server_flags = packet_get_int(); | |
972 | packet_set_protocol_flags(server_flags); | |
973 | ||
974 | supported_ciphers = packet_get_int(); | |
975 | supported_authentications = packet_get_int(); | |
976 | ||
977 | debug("Received server public key (%d bits) and host key (%d bits).", | |
978 | BN_num_bits(public_key->n), BN_num_bits(host_key->n)); | |
979 | ||
980 | packet_integrity_check(payload_len, | |
981 | 8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4, | |
982 | SSH_SMSG_PUBLIC_KEY); | |
fa08c86b | 983 | k.type = KEY_RSA1; |
a306f2dd | 984 | k.rsa = host_key; |
f49bc4f7 | 985 | if (verify_host_key(host, hostaddr, &k) == -1) |
986 | fatal("host_key verification failed"); | |
a306f2dd | 987 | |
988 | client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN; | |
989 | ||
990 | compute_session_id(session_id, cookie, host_key->n, public_key->n); | |
991 | ||
992 | /* Generate a session key. */ | |
993 | arc4random_stir(); | |
994 | ||
995 | /* | |
996 | * Generate an encryption key for the session. The key is a 256 bit | |
997 | * random number, interpreted as a 32-byte key, with the least | |
998 | * significant 8 bits being the first byte of the key. | |
999 | */ | |
1000 | for (i = 0; i < 32; i++) { | |
1001 | if (i % 4 == 0) | |
1002 | rand = arc4random(); | |
1003 | session_key[i] = rand & 0xff; | |
1004 | rand >>= 8; | |
1005 | } | |
1006 | ||
1007 | /* | |
1008 | * According to the protocol spec, the first byte of the session key | |
1009 | * is the highest byte of the integer. The session key is xored with | |
1010 | * the first 16 bytes of the session id. | |
1011 | */ | |
1012 | key = BN_new(); | |
1013 | BN_set_word(key, 0); | |
1014 | for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) { | |
1015 | BN_lshift(key, key, 8); | |
1016 | if (i < 16) | |
1017 | BN_add_word(key, session_key[i] ^ session_id[i]); | |
1018 | else | |
1019 | BN_add_word(key, session_key[i]); | |
1020 | } | |
1021 | ||
1022 | /* | |
1023 | * Encrypt the integer using the public key and host key of the | |
1024 | * server (key with smaller modulus first). | |
1025 | */ | |
1026 | if (BN_cmp(public_key->n, host_key->n) < 0) { | |
1027 | /* Public key has smaller modulus. */ | |
1028 | if (BN_num_bits(host_key->n) < | |
1029 | BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) { | |
1030 | fatal("respond_to_rsa_challenge: host_key %d < public_key %d + " | |
1031 | "SSH_KEY_BITS_RESERVED %d", | |
1032 | BN_num_bits(host_key->n), | |
1033 | BN_num_bits(public_key->n), | |
1034 | SSH_KEY_BITS_RESERVED); | |
1035 | } | |
1036 | rsa_public_encrypt(key, key, public_key); | |
1037 | rsa_public_encrypt(key, key, host_key); | |
1038 | } else { | |
1039 | /* Host key has smaller modulus (or they are equal). */ | |
1040 | if (BN_num_bits(public_key->n) < | |
1041 | BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) { | |
1042 | fatal("respond_to_rsa_challenge: public_key %d < host_key %d + " | |
1043 | "SSH_KEY_BITS_RESERVED %d", | |
1044 | BN_num_bits(public_key->n), | |
1045 | BN_num_bits(host_key->n), | |
1046 | SSH_KEY_BITS_RESERVED); | |
1047 | } | |
1048 | rsa_public_encrypt(key, key, host_key); | |
1049 | rsa_public_encrypt(key, key, public_key); | |
1050 | } | |
1051 | ||
1052 | /* Destroy the public keys since we no longer need them. */ | |
1053 | RSA_free(public_key); | |
1054 | RSA_free(host_key); | |
1055 | ||
c523303b | 1056 | if (options.cipher == SSH_CIPHER_NOT_SET) { |
1057 | if (cipher_mask_ssh1(1) & supported_ciphers & (1 << ssh_cipher_default)) | |
1058 | options.cipher = ssh_cipher_default; | |
1059 | } else if (options.cipher == SSH_CIPHER_ILLEGAL || | |
1060 | !(cipher_mask_ssh1(1) & (1 << options.cipher))) { | |
d0c832f3 | 1061 | log("No valid SSH1 cipher, using %.100s instead.", |
94ec8c6b | 1062 | cipher_name(ssh_cipher_default)); |
1063 | options.cipher = ssh_cipher_default; | |
a306f2dd | 1064 | } |
1065 | /* Check that the selected cipher is supported. */ | |
1066 | if (!(supported_ciphers & (1 << options.cipher))) | |
1067 | fatal("Selected cipher type %.100s not supported by server.", | |
1068 | cipher_name(options.cipher)); | |
1069 | ||
1070 | debug("Encryption type: %.100s", cipher_name(options.cipher)); | |
1071 | ||
1072 | /* Send the encrypted session key to the server. */ | |
1073 | packet_start(SSH_CMSG_SESSION_KEY); | |
1074 | packet_put_char(options.cipher); | |
1075 | ||
1076 | /* Send the cookie back to the server. */ | |
1077 | for (i = 0; i < 8; i++) | |
1078 | packet_put_char(cookie[i]); | |
1079 | ||
1080 | /* Send and destroy the encrypted encryption key integer. */ | |
1081 | packet_put_bignum(key); | |
1082 | BN_clear_free(key); | |
1083 | ||
1084 | /* Send protocol flags. */ | |
1085 | packet_put_int(client_flags); | |
1086 | ||
1087 | /* Send the packet now. */ | |
1088 | packet_send(); | |
1089 | packet_write_wait(); | |
1090 | ||
1091 | debug("Sent encrypted session key."); | |
1092 | ||
1093 | /* Set the encryption key. */ | |
1094 | packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher); | |
1095 | ||
1096 | /* We will no longer need the session key here. Destroy any extra copies. */ | |
1097 | memset(session_key, 0, sizeof(session_key)); | |
1098 | ||
1099 | /* | |
1100 | * Expect a success message from the server. Note that this message | |
1101 | * will be received in encrypted form. | |
1102 | */ | |
1103 | packet_read_expect(&payload_len, SSH_SMSG_SUCCESS); | |
1104 | ||
1105 | debug("Received encrypted confirmation."); | |
1106 | } | |
1107 | ||
1108 | /* | |
1109 | * Authenticate user | |
1110 | */ | |
1111 | void | |
8002af61 | 1112 | ssh_userauth1(const char *local_user, const char *server_user, char *host, |
1113 | Key **keys, int nkeys) | |
a306f2dd | 1114 | { |
ced49be2 | 1115 | #ifdef KRB5 |
1116 | krb5_context context = NULL; | |
1117 | krb5_auth_context auth_context = NULL; | |
1118 | #endif | |
a306f2dd | 1119 | int i, type; |
1120 | int payload_len; | |
ced49be2 | 1121 | |
a306f2dd | 1122 | if (supported_authentications == 0) |
8002af61 | 1123 | fatal("ssh_userauth1: server supports no auth methods"); |
a306f2dd | 1124 | |
1125 | /* Send the name of the user to log in as on the server. */ | |
1126 | packet_start(SSH_CMSG_USER); | |
449c5ba5 | 1127 | packet_put_cstring(server_user); |
a306f2dd | 1128 | packet_send(); |
1129 | packet_write_wait(); | |
1130 | ||
1131 | /* | |
1132 | * The server should respond with success if no authentication is | |
1133 | * needed (the user has no password). Otherwise the server responds | |
1134 | * with failure. | |
1135 | */ | |
1136 | type = packet_read(&payload_len); | |
1137 | ||
1138 | /* check whether the connection was accepted without authentication. */ | |
1139 | if (type == SSH_SMSG_SUCCESS) | |
ced49be2 | 1140 | goto success; |
a306f2dd | 1141 | if (type != SSH_SMSG_FAILURE) |
ced49be2 | 1142 | packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER", type); |
1143 | ||
1144 | #ifdef KRB5 | |
1145 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1146 | options.kerberos_authentication) { | |
1147 | debug("Trying Kerberos v5 authentication."); | |
1148 | ||
1149 | if (try_krb5_authentication(&context, &auth_context)) { | |
1150 | type = packet_read(&payload_len); | |
1151 | if (type == SSH_SMSG_SUCCESS) | |
1152 | goto success; | |
1153 | if (type != SSH_SMSG_FAILURE) | |
1154 | packet_disconnect("Protocol error: got %d in response to Kerberos v5 auth", type); | |
1155 | } | |
a306f2dd | 1156 | } |
ced49be2 | 1157 | #endif /* KRB5 */ |
1158 | ||
a306f2dd | 1159 | #ifdef KRB4 |
1160 | if ((supported_authentications & (1 << SSH_AUTH_KERBEROS)) && | |
1161 | options.kerberos_authentication) { | |
ced49be2 | 1162 | debug("Trying Kerberos v4 authentication."); |
1163 | ||
1164 | if (try_krb4_authentication()) { | |
a306f2dd | 1165 | type = packet_read(&payload_len); |
1166 | if (type == SSH_SMSG_SUCCESS) | |
ced49be2 | 1167 | goto success; |
a306f2dd | 1168 | if (type != SSH_SMSG_FAILURE) |
ced49be2 | 1169 | packet_disconnect("Protocol error: got %d in response to Kerberos v4 auth", type); |
a306f2dd | 1170 | } |
1171 | } | |
1172 | #endif /* KRB4 */ | |
ced49be2 | 1173 | |
a306f2dd | 1174 | /* |
1175 | * Use rhosts authentication if running in privileged socket and we | |
1176 | * do not wish to remain anonymous. | |
1177 | */ | |
1178 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) && | |
1179 | options.rhosts_authentication) { | |
1180 | debug("Trying rhosts authentication."); | |
1181 | packet_start(SSH_CMSG_AUTH_RHOSTS); | |
449c5ba5 | 1182 | packet_put_cstring(local_user); |
a306f2dd | 1183 | packet_send(); |
1184 | packet_write_wait(); | |
1185 | ||
1186 | /* The server should respond with success or failure. */ | |
1187 | type = packet_read(&payload_len); | |
1188 | if (type == SSH_SMSG_SUCCESS) | |
ced49be2 | 1189 | goto success; |
a306f2dd | 1190 | if (type != SSH_SMSG_FAILURE) |
1191 | packet_disconnect("Protocol error: got %d in response to rhosts auth", | |
1192 | type); | |
1193 | } | |
1194 | /* | |
1195 | * Try .rhosts or /etc/hosts.equiv authentication with RSA host | |
1196 | * authentication. | |
1197 | */ | |
1198 | if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) && | |
8002af61 | 1199 | options.rhosts_rsa_authentication) { |
1200 | for (i = 0; i < nkeys; i++) { | |
eba4bef7 | 1201 | if (keys[i] != NULL && keys[i]->type == KEY_RSA1 && |
8002af61 | 1202 | try_rhosts_rsa_authentication(local_user, keys[i])) |
ced49be2 | 1203 | goto success; |
8002af61 | 1204 | } |
a306f2dd | 1205 | } |
1206 | /* Try RSA authentication if the server supports it. */ | |
1207 | if ((supported_authentications & (1 << SSH_AUTH_RSA)) && | |
1208 | options.rsa_authentication) { | |
1209 | /* | |
1210 | * Try RSA authentication using the authentication agent. The | |
1211 | * agent is tried first because no passphrase is needed for | |
1212 | * it, whereas identity files may require passphrases. | |
1213 | */ | |
1214 | if (try_agent_authentication()) | |
ced49be2 | 1215 | goto success; |
a306f2dd | 1216 | |
1217 | /* Try RSA authentication for each identity. */ | |
1218 | for (i = 0; i < options.num_identity_files; i++) | |
fee56204 | 1219 | if (options.identity_keys[i] != NULL && |
1220 | options.identity_keys[i]->type == KEY_RSA1 && | |
fa08c86b | 1221 | try_rsa_authentication(options.identity_files[i])) |
ced49be2 | 1222 | goto success; |
a306f2dd | 1223 | } |
d464095c | 1224 | /* Try challenge response authentication if the server supports it. */ |
a306f2dd | 1225 | if ((supported_authentications & (1 << SSH_AUTH_TIS)) && |
5ba55ada | 1226 | options.challenge_response_authentication && !options.batch_mode) { |
1227 | if (try_challenge_response_authentication()) | |
ced49be2 | 1228 | goto success; |
a306f2dd | 1229 | } |
1230 | /* Try password authentication if the server supports it. */ | |
1231 | if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) && | |
1232 | options.password_authentication && !options.batch_mode) { | |
1233 | char prompt[80]; | |
1234 | ||
b3b9ad8e | 1235 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", |
a306f2dd | 1236 | server_user, host); |
1237 | if (try_password_authentication(prompt)) | |
ced49be2 | 1238 | goto success; |
a306f2dd | 1239 | } |
1240 | /* All authentication methods have failed. Exit with an error message. */ | |
1241 | fatal("Permission denied."); | |
1242 | /* NOTREACHED */ | |
ced49be2 | 1243 | |
1244 | success: | |
1245 | #ifdef KRB5 | |
1246 | /* Try Kerberos v5 TGT passing. */ | |
1247 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1248 | options.kerberos_tgt_passing && context && auth_context) { | |
1249 | if (options.cipher == SSH_CIPHER_NONE) | |
1250 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1251 | send_krb5_tgt(context, auth_context); | |
1252 | } | |
1253 | if (auth_context) | |
1254 | krb5_auth_con_free(context, auth_context); | |
1255 | if (context) | |
1256 | krb5_free_context(context); | |
1257 | #endif | |
1258 | ||
1259 | #ifdef AFS | |
1260 | /* Try Kerberos v4 TGT passing if the server supports it. */ | |
1261 | if ((supported_authentications & (1 << SSH_PASS_KERBEROS_TGT)) && | |
1262 | options.kerberos_tgt_passing) { | |
1263 | if (options.cipher == SSH_CIPHER_NONE) | |
1264 | log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!"); | |
1265 | send_krb4_tgt(); | |
1266 | } | |
1267 | /* Try AFS token passing if the server supports it. */ | |
1268 | if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) && | |
1269 | options.afs_token_passing && k_hasafs()) { | |
1270 | if (options.cipher == SSH_CIPHER_NONE) | |
1271 | log("WARNING: Encryption is disabled! Token will be transmitted in the clear!"); | |
1272 | send_afs_tokens(); | |
1273 | } | |
1274 | #endif /* AFS */ | |
a306f2dd | 1275 | } |