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1 | /* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 djm Exp $ */ | |
2 | /* | |
3 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
4 | * Copyright (c) 2008 Damien Miller. All rights reserved. | |
5 | * | |
6 | * Redistribution and use in source and binary forms, with or without | |
7 | * modification, are permitted provided that the following conditions | |
8 | * are met: | |
9 | * 1. Redistributions of source code must retain the above copyright | |
10 | * notice, this list of conditions and the following disclaimer. | |
11 | * 2. Redistributions in binary form must reproduce the above copyright | |
12 | * notice, this list of conditions and the following disclaimer in the | |
13 | * documentation and/or other materials provided with the distribution. | |
14 | * | |
15 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
16 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
17 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
18 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
19 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
20 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
21 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
22 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
23 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
24 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
25 | */ | |
26 | ||
27 | #include "includes.h" | |
28 | ||
29 | #include <sys/types.h> | |
30 | #include <sys/socket.h> | |
31 | #include <sys/wait.h> | |
32 | #include <sys/stat.h> | |
33 | ||
34 | #include <errno.h> | |
35 | #include <netdb.h> | |
36 | #include <pwd.h> | |
37 | #include <signal.h> | |
38 | #include <stdarg.h> | |
39 | #include <stdio.h> | |
40 | #include <string.h> | |
41 | #include <unistd.h> | |
42 | #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) | |
43 | #include <vis.h> | |
44 | #endif | |
45 | ||
46 | #include "openbsd-compat/sys-queue.h" | |
47 | ||
48 | #include "xmalloc.h" | |
49 | #include "ssh.h" | |
50 | #include "ssh2.h" | |
51 | #include "buffer.h" | |
52 | #include "packet.h" | |
53 | #include "compat.h" | |
54 | #include "cipher.h" | |
55 | #include "key.h" | |
56 | #include "kex.h" | |
57 | #include "myproposal.h" | |
58 | #include "sshconnect.h" | |
59 | #include "authfile.h" | |
60 | #include "dh.h" | |
61 | #include "authfd.h" | |
62 | #include "log.h" | |
63 | #include "readconf.h" | |
64 | #include "misc.h" | |
65 | #include "match.h" | |
66 | #include "dispatch.h" | |
67 | #include "canohost.h" | |
68 | #include "msg.h" | |
69 | #include "pathnames.h" | |
70 | #include "uidswap.h" | |
71 | #include "jpake.h" | |
72 | ||
73 | #ifdef GSSAPI | |
74 | #include "ssh-gss.h" | |
75 | #endif | |
76 | ||
77 | /* import */ | |
78 | extern char *client_version_string; | |
79 | extern char *server_version_string; | |
80 | extern Options options; | |
81 | ||
82 | /* | |
83 | * SSH2 key exchange | |
84 | */ | |
85 | ||
86 | u_char *session_id2 = NULL; | |
87 | u_int session_id2_len = 0; | |
88 | ||
89 | char *xxx_host; | |
90 | struct sockaddr *xxx_hostaddr; | |
91 | ||
92 | Kex *xxx_kex = NULL; | |
93 | ||
94 | static int | |
95 | verify_host_key_callback(Key *hostkey) | |
96 | { | |
97 | if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) | |
98 | fatal("Host key verification failed."); | |
99 | return 0; | |
100 | } | |
101 | ||
102 | void | |
103 | ssh_kex2(char *host, struct sockaddr *hostaddr) | |
104 | { | |
105 | Kex *kex; | |
106 | ||
107 | xxx_host = host; | |
108 | xxx_hostaddr = hostaddr; | |
109 | ||
110 | if (options.ciphers == (char *)-1) { | |
111 | logit("No valid ciphers for protocol version 2 given, using defaults."); | |
112 | options.ciphers = NULL; | |
113 | } | |
114 | if (options.ciphers != NULL) { | |
115 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
116 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
117 | } | |
118 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
119 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
120 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
121 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
122 | if (options.compression) { | |
123 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
124 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; | |
125 | } else { | |
126 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
127 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; | |
128 | } | |
129 | if (options.macs != NULL) { | |
130 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
131 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
132 | } | |
133 | if (options.hostkeyalgorithms != NULL) | |
134 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = | |
135 | options.hostkeyalgorithms; | |
136 | ||
137 | if (options.rekey_limit) | |
138 | packet_set_rekey_limit((u_int32_t)options.rekey_limit); | |
139 | ||
140 | /* start key exchange */ | |
141 | kex = kex_setup(myproposal); | |
142 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; | |
143 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; | |
144 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; | |
145 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; | |
146 | kex->client_version_string=client_version_string; | |
147 | kex->server_version_string=server_version_string; | |
148 | kex->verify_host_key=&verify_host_key_callback; | |
149 | ||
150 | xxx_kex = kex; | |
151 | ||
152 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
153 | ||
154 | session_id2 = kex->session_id; | |
155 | session_id2_len = kex->session_id_len; | |
156 | ||
157 | #ifdef DEBUG_KEXDH | |
158 | /* send 1st encrypted/maced/compressed message */ | |
159 | packet_start(SSH2_MSG_IGNORE); | |
160 | packet_put_cstring("markus"); | |
161 | packet_send(); | |
162 | packet_write_wait(); | |
163 | #endif | |
164 | } | |
165 | ||
166 | /* | |
167 | * Authenticate user | |
168 | */ | |
169 | ||
170 | typedef struct Authctxt Authctxt; | |
171 | typedef struct Authmethod Authmethod; | |
172 | typedef struct identity Identity; | |
173 | typedef struct idlist Idlist; | |
174 | ||
175 | struct identity { | |
176 | TAILQ_ENTRY(identity) next; | |
177 | AuthenticationConnection *ac; /* set if agent supports key */ | |
178 | Key *key; /* public/private key */ | |
179 | char *filename; /* comment for agent-only keys */ | |
180 | int tried; | |
181 | int isprivate; /* key points to the private key */ | |
182 | }; | |
183 | TAILQ_HEAD(idlist, identity); | |
184 | ||
185 | struct Authctxt { | |
186 | const char *server_user; | |
187 | const char *local_user; | |
188 | const char *host; | |
189 | const char *service; | |
190 | Authmethod *method; | |
191 | int success; | |
192 | char *authlist; | |
193 | /* pubkey */ | |
194 | Idlist keys; | |
195 | AuthenticationConnection *agent; | |
196 | /* hostbased */ | |
197 | Sensitive *sensitive; | |
198 | /* kbd-interactive */ | |
199 | int info_req_seen; | |
200 | /* generic */ | |
201 | void *methoddata; | |
202 | }; | |
203 | struct Authmethod { | |
204 | char *name; /* string to compare against server's list */ | |
205 | int (*userauth)(Authctxt *authctxt); | |
206 | void (*cleanup)(Authctxt *authctxt); | |
207 | int *enabled; /* flag in option struct that enables method */ | |
208 | int *batch_flag; /* flag in option struct that disables method */ | |
209 | }; | |
210 | ||
211 | void input_userauth_success(int, u_int32_t, void *); | |
212 | void input_userauth_failure(int, u_int32_t, void *); | |
213 | void input_userauth_banner(int, u_int32_t, void *); | |
214 | void input_userauth_error(int, u_int32_t, void *); | |
215 | void input_userauth_info_req(int, u_int32_t, void *); | |
216 | void input_userauth_pk_ok(int, u_int32_t, void *); | |
217 | void input_userauth_passwd_changereq(int, u_int32_t, void *); | |
218 | void input_userauth_jpake_server_step1(int, u_int32_t, void *); | |
219 | void input_userauth_jpake_server_step2(int, u_int32_t, void *); | |
220 | void input_userauth_jpake_server_confirm(int, u_int32_t, void *); | |
221 | ||
222 | int userauth_none(Authctxt *); | |
223 | int userauth_pubkey(Authctxt *); | |
224 | int userauth_passwd(Authctxt *); | |
225 | int userauth_kbdint(Authctxt *); | |
226 | int userauth_hostbased(Authctxt *); | |
227 | int userauth_jpake(Authctxt *); | |
228 | ||
229 | void userauth_jpake_cleanup(Authctxt *); | |
230 | ||
231 | #ifdef GSSAPI | |
232 | int userauth_gssapi(Authctxt *authctxt); | |
233 | void input_gssapi_response(int type, u_int32_t, void *); | |
234 | void input_gssapi_token(int type, u_int32_t, void *); | |
235 | void input_gssapi_hash(int type, u_int32_t, void *); | |
236 | void input_gssapi_error(int, u_int32_t, void *); | |
237 | void input_gssapi_errtok(int, u_int32_t, void *); | |
238 | #endif | |
239 | ||
240 | void userauth(Authctxt *, char *); | |
241 | ||
242 | static int sign_and_send_pubkey(Authctxt *, Identity *); | |
243 | static void pubkey_prepare(Authctxt *); | |
244 | static void pubkey_cleanup(Authctxt *); | |
245 | static Key *load_identity_file(char *); | |
246 | ||
247 | static Authmethod *authmethod_get(char *authlist); | |
248 | static Authmethod *authmethod_lookup(const char *name); | |
249 | static char *authmethods_get(void); | |
250 | ||
251 | Authmethod authmethods[] = { | |
252 | #ifdef GSSAPI | |
253 | {"gssapi-with-mic", | |
254 | userauth_gssapi, | |
255 | NULL, | |
256 | &options.gss_authentication, | |
257 | NULL}, | |
258 | #endif | |
259 | {"hostbased", | |
260 | userauth_hostbased, | |
261 | NULL, | |
262 | &options.hostbased_authentication, | |
263 | NULL}, | |
264 | {"publickey", | |
265 | userauth_pubkey, | |
266 | NULL, | |
267 | &options.pubkey_authentication, | |
268 | NULL}, | |
269 | #ifdef JPAKE | |
270 | {"jpake-01@openssh.com", | |
271 | userauth_jpake, | |
272 | userauth_jpake_cleanup, | |
273 | &options.zero_knowledge_password_authentication, | |
274 | &options.batch_mode}, | |
275 | #endif | |
276 | {"keyboard-interactive", | |
277 | userauth_kbdint, | |
278 | NULL, | |
279 | &options.kbd_interactive_authentication, | |
280 | &options.batch_mode}, | |
281 | {"password", | |
282 | userauth_passwd, | |
283 | NULL, | |
284 | &options.password_authentication, | |
285 | &options.batch_mode}, | |
286 | {"none", | |
287 | userauth_none, | |
288 | NULL, | |
289 | NULL, | |
290 | NULL}, | |
291 | {NULL, NULL, NULL, NULL, NULL} | |
292 | }; | |
293 | ||
294 | void | |
295 | ssh_userauth2(const char *local_user, const char *server_user, char *host, | |
296 | Sensitive *sensitive) | |
297 | { | |
298 | Authctxt authctxt; | |
299 | int type; | |
300 | ||
301 | if (options.challenge_response_authentication) | |
302 | options.kbd_interactive_authentication = 1; | |
303 | ||
304 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
305 | packet_put_cstring("ssh-userauth"); | |
306 | packet_send(); | |
307 | debug("SSH2_MSG_SERVICE_REQUEST sent"); | |
308 | packet_write_wait(); | |
309 | type = packet_read(); | |
310 | if (type != SSH2_MSG_SERVICE_ACCEPT) | |
311 | fatal("Server denied authentication request: %d", type); | |
312 | if (packet_remaining() > 0) { | |
313 | char *reply = packet_get_string(NULL); | |
314 | debug2("service_accept: %s", reply); | |
315 | xfree(reply); | |
316 | } else { | |
317 | debug2("buggy server: service_accept w/o service"); | |
318 | } | |
319 | packet_check_eom(); | |
320 | debug("SSH2_MSG_SERVICE_ACCEPT received"); | |
321 | ||
322 | if (options.preferred_authentications == NULL) | |
323 | options.preferred_authentications = authmethods_get(); | |
324 | ||
325 | /* setup authentication context */ | |
326 | memset(&authctxt, 0, sizeof(authctxt)); | |
327 | pubkey_prepare(&authctxt); | |
328 | authctxt.server_user = server_user; | |
329 | authctxt.local_user = local_user; | |
330 | authctxt.host = host; | |
331 | authctxt.service = "ssh-connection"; /* service name */ | |
332 | authctxt.success = 0; | |
333 | authctxt.method = authmethod_lookup("none"); | |
334 | authctxt.authlist = NULL; | |
335 | authctxt.methoddata = NULL; | |
336 | authctxt.sensitive = sensitive; | |
337 | authctxt.info_req_seen = 0; | |
338 | if (authctxt.method == NULL) | |
339 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
340 | ||
341 | /* initial userauth request */ | |
342 | userauth_none(&authctxt); | |
343 | ||
344 | dispatch_init(&input_userauth_error); | |
345 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
346 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
347 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); | |
348 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ | |
349 | ||
350 | pubkey_cleanup(&authctxt); | |
351 | dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); | |
352 | ||
353 | debug("Authentication succeeded (%s).", authctxt.method->name); | |
354 | } | |
355 | ||
356 | void | |
357 | userauth(Authctxt *authctxt, char *authlist) | |
358 | { | |
359 | if (authctxt->method != NULL && authctxt->method->cleanup != NULL) | |
360 | authctxt->method->cleanup(authctxt); | |
361 | ||
362 | if (authctxt->methoddata) { | |
363 | xfree(authctxt->methoddata); | |
364 | authctxt->methoddata = NULL; | |
365 | } | |
366 | if (authlist == NULL) { | |
367 | authlist = authctxt->authlist; | |
368 | } else { | |
369 | if (authctxt->authlist) | |
370 | xfree(authctxt->authlist); | |
371 | authctxt->authlist = authlist; | |
372 | } | |
373 | for (;;) { | |
374 | Authmethod *method = authmethod_get(authlist); | |
375 | if (method == NULL) | |
376 | fatal("Permission denied (%s).", authlist); | |
377 | authctxt->method = method; | |
378 | ||
379 | /* reset the per method handler */ | |
380 | dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, | |
381 | SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); | |
382 | ||
383 | /* and try new method */ | |
384 | if (method->userauth(authctxt) != 0) { | |
385 | debug2("we sent a %s packet, wait for reply", method->name); | |
386 | break; | |
387 | } else { | |
388 | debug2("we did not send a packet, disable method"); | |
389 | method->enabled = NULL; | |
390 | } | |
391 | } | |
392 | } | |
393 | ||
394 | /* ARGSUSED */ | |
395 | void | |
396 | input_userauth_error(int type, u_int32_t seq, void *ctxt) | |
397 | { | |
398 | fatal("input_userauth_error: bad message during authentication: " | |
399 | "type %d", type); | |
400 | } | |
401 | ||
402 | /* ARGSUSED */ | |
403 | void | |
404 | input_userauth_banner(int type, u_int32_t seq, void *ctxt) | |
405 | { | |
406 | char *msg, *raw, *lang; | |
407 | u_int len; | |
408 | ||
409 | debug3("input_userauth_banner"); | |
410 | raw = packet_get_string(&len); | |
411 | lang = packet_get_string(NULL); | |
412 | if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { | |
413 | if (len > 65536) | |
414 | len = 65536; | |
415 | msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ | |
416 | strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL); | |
417 | fprintf(stderr, "%s", msg); | |
418 | xfree(msg); | |
419 | } | |
420 | xfree(raw); | |
421 | xfree(lang); | |
422 | } | |
423 | ||
424 | /* ARGSUSED */ | |
425 | void | |
426 | input_userauth_success(int type, u_int32_t seq, void *ctxt) | |
427 | { | |
428 | Authctxt *authctxt = ctxt; | |
429 | if (authctxt == NULL) | |
430 | fatal("input_userauth_success: no authentication context"); | |
431 | if (authctxt->authlist) { | |
432 | xfree(authctxt->authlist); | |
433 | authctxt->authlist = NULL; | |
434 | } | |
435 | if (authctxt->methoddata) { | |
436 | xfree(authctxt->methoddata); | |
437 | authctxt->methoddata = NULL; | |
438 | } | |
439 | authctxt->success = 1; /* break out */ | |
440 | } | |
441 | ||
442 | /* ARGSUSED */ | |
443 | void | |
444 | input_userauth_failure(int type, u_int32_t seq, void *ctxt) | |
445 | { | |
446 | Authctxt *authctxt = ctxt; | |
447 | char *authlist = NULL; | |
448 | int partial; | |
449 | ||
450 | if (authctxt == NULL) | |
451 | fatal("input_userauth_failure: no authentication context"); | |
452 | ||
453 | authlist = packet_get_string(NULL); | |
454 | partial = packet_get_char(); | |
455 | packet_check_eom(); | |
456 | ||
457 | if (partial != 0) | |
458 | logit("Authenticated with partial success."); | |
459 | debug("Authentications that can continue: %s", authlist); | |
460 | ||
461 | userauth(authctxt, authlist); | |
462 | } | |
463 | ||
464 | /* ARGSUSED */ | |
465 | void | |
466 | input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) | |
467 | { | |
468 | Authctxt *authctxt = ctxt; | |
469 | Key *key = NULL; | |
470 | Identity *id = NULL; | |
471 | Buffer b; | |
472 | int pktype, sent = 0; | |
473 | u_int alen, blen; | |
474 | char *pkalg, *fp; | |
475 | u_char *pkblob; | |
476 | ||
477 | if (authctxt == NULL) | |
478 | fatal("input_userauth_pk_ok: no authentication context"); | |
479 | if (datafellows & SSH_BUG_PKOK) { | |
480 | /* this is similar to SSH_BUG_PKAUTH */ | |
481 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
482 | pkblob = packet_get_string(&blen); | |
483 | buffer_init(&b); | |
484 | buffer_append(&b, pkblob, blen); | |
485 | pkalg = buffer_get_string(&b, &alen); | |
486 | buffer_free(&b); | |
487 | } else { | |
488 | pkalg = packet_get_string(&alen); | |
489 | pkblob = packet_get_string(&blen); | |
490 | } | |
491 | packet_check_eom(); | |
492 | ||
493 | debug("Server accepts key: pkalg %s blen %u", pkalg, blen); | |
494 | ||
495 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { | |
496 | debug("unknown pkalg %s", pkalg); | |
497 | goto done; | |
498 | } | |
499 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
500 | debug("no key from blob. pkalg %s", pkalg); | |
501 | goto done; | |
502 | } | |
503 | if (key->type != pktype) { | |
504 | error("input_userauth_pk_ok: type mismatch " | |
505 | "for decoded key (received %d, expected %d)", | |
506 | key->type, pktype); | |
507 | goto done; | |
508 | } | |
509 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); | |
510 | debug2("input_userauth_pk_ok: fp %s", fp); | |
511 | xfree(fp); | |
512 | ||
513 | /* | |
514 | * search keys in the reverse order, because last candidate has been | |
515 | * moved to the end of the queue. this also avoids confusion by | |
516 | * duplicate keys | |
517 | */ | |
518 | TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { | |
519 | if (key_equal(key, id->key)) { | |
520 | sent = sign_and_send_pubkey(authctxt, id); | |
521 | break; | |
522 | } | |
523 | } | |
524 | done: | |
525 | if (key != NULL) | |
526 | key_free(key); | |
527 | xfree(pkalg); | |
528 | xfree(pkblob); | |
529 | ||
530 | /* try another method if we did not send a packet */ | |
531 | if (sent == 0) | |
532 | userauth(authctxt, NULL); | |
533 | } | |
534 | ||
535 | #ifdef GSSAPI | |
536 | int | |
537 | userauth_gssapi(Authctxt *authctxt) | |
538 | { | |
539 | Gssctxt *gssctxt = NULL; | |
540 | static gss_OID_set gss_supported = NULL; | |
541 | static u_int mech = 0; | |
542 | OM_uint32 min; | |
543 | int ok = 0; | |
544 | ||
545 | /* Try one GSSAPI method at a time, rather than sending them all at | |
546 | * once. */ | |
547 | ||
548 | if (gss_supported == NULL) | |
549 | gss_indicate_mechs(&min, &gss_supported); | |
550 | ||
551 | /* Check to see if the mechanism is usable before we offer it */ | |
552 | while (mech < gss_supported->count && !ok) { | |
553 | /* My DER encoding requires length<128 */ | |
554 | if (gss_supported->elements[mech].length < 128 && | |
555 | ssh_gssapi_check_mechanism(&gssctxt, | |
556 | &gss_supported->elements[mech], authctxt->host)) { | |
557 | ok = 1; /* Mechanism works */ | |
558 | } else { | |
559 | mech++; | |
560 | } | |
561 | } | |
562 | ||
563 | if (!ok) | |
564 | return 0; | |
565 | ||
566 | authctxt->methoddata=(void *)gssctxt; | |
567 | ||
568 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
569 | packet_put_cstring(authctxt->server_user); | |
570 | packet_put_cstring(authctxt->service); | |
571 | packet_put_cstring(authctxt->method->name); | |
572 | ||
573 | packet_put_int(1); | |
574 | ||
575 | packet_put_int((gss_supported->elements[mech].length) + 2); | |
576 | packet_put_char(SSH_GSS_OIDTYPE); | |
577 | packet_put_char(gss_supported->elements[mech].length); | |
578 | packet_put_raw(gss_supported->elements[mech].elements, | |
579 | gss_supported->elements[mech].length); | |
580 | ||
581 | packet_send(); | |
582 | ||
583 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); | |
584 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); | |
585 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); | |
586 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); | |
587 | ||
588 | mech++; /* Move along to next candidate */ | |
589 | ||
590 | return 1; | |
591 | } | |
592 | ||
593 | static OM_uint32 | |
594 | process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) | |
595 | { | |
596 | Authctxt *authctxt = ctxt; | |
597 | Gssctxt *gssctxt = authctxt->methoddata; | |
598 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | |
599 | gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; | |
600 | gss_buffer_desc gssbuf; | |
601 | OM_uint32 status, ms, flags; | |
602 | Buffer b; | |
603 | ||
604 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, | |
605 | recv_tok, &send_tok, &flags); | |
606 | ||
607 | if (send_tok.length > 0) { | |
608 | if (GSS_ERROR(status)) | |
609 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); | |
610 | else | |
611 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); | |
612 | ||
613 | packet_put_string(send_tok.value, send_tok.length); | |
614 | packet_send(); | |
615 | gss_release_buffer(&ms, &send_tok); | |
616 | } | |
617 | ||
618 | if (status == GSS_S_COMPLETE) { | |
619 | /* send either complete or MIC, depending on mechanism */ | |
620 | if (!(flags & GSS_C_INTEG_FLAG)) { | |
621 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); | |
622 | packet_send(); | |
623 | } else { | |
624 | ssh_gssapi_buildmic(&b, authctxt->server_user, | |
625 | authctxt->service, "gssapi-with-mic"); | |
626 | ||
627 | gssbuf.value = buffer_ptr(&b); | |
628 | gssbuf.length = buffer_len(&b); | |
629 | ||
630 | status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); | |
631 | ||
632 | if (!GSS_ERROR(status)) { | |
633 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); | |
634 | packet_put_string(mic.value, mic.length); | |
635 | ||
636 | packet_send(); | |
637 | } | |
638 | ||
639 | buffer_free(&b); | |
640 | gss_release_buffer(&ms, &mic); | |
641 | } | |
642 | } | |
643 | ||
644 | return status; | |
645 | } | |
646 | ||
647 | /* ARGSUSED */ | |
648 | void | |
649 | input_gssapi_response(int type, u_int32_t plen, void *ctxt) | |
650 | { | |
651 | Authctxt *authctxt = ctxt; | |
652 | Gssctxt *gssctxt; | |
653 | int oidlen; | |
654 | char *oidv; | |
655 | ||
656 | if (authctxt == NULL) | |
657 | fatal("input_gssapi_response: no authentication context"); | |
658 | gssctxt = authctxt->methoddata; | |
659 | ||
660 | /* Setup our OID */ | |
661 | oidv = packet_get_string(&oidlen); | |
662 | ||
663 | if (oidlen <= 2 || | |
664 | oidv[0] != SSH_GSS_OIDTYPE || | |
665 | oidv[1] != oidlen - 2) { | |
666 | xfree(oidv); | |
667 | debug("Badly encoded mechanism OID received"); | |
668 | userauth(authctxt, NULL); | |
669 | return; | |
670 | } | |
671 | ||
672 | if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) | |
673 | fatal("Server returned different OID than expected"); | |
674 | ||
675 | packet_check_eom(); | |
676 | ||
677 | xfree(oidv); | |
678 | ||
679 | if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { | |
680 | /* Start again with next method on list */ | |
681 | debug("Trying to start again"); | |
682 | userauth(authctxt, NULL); | |
683 | return; | |
684 | } | |
685 | } | |
686 | ||
687 | /* ARGSUSED */ | |
688 | void | |
689 | input_gssapi_token(int type, u_int32_t plen, void *ctxt) | |
690 | { | |
691 | Authctxt *authctxt = ctxt; | |
692 | gss_buffer_desc recv_tok; | |
693 | OM_uint32 status; | |
694 | u_int slen; | |
695 | ||
696 | if (authctxt == NULL) | |
697 | fatal("input_gssapi_response: no authentication context"); | |
698 | ||
699 | recv_tok.value = packet_get_string(&slen); | |
700 | recv_tok.length = slen; /* safe typecast */ | |
701 | ||
702 | packet_check_eom(); | |
703 | ||
704 | status = process_gssapi_token(ctxt, &recv_tok); | |
705 | ||
706 | xfree(recv_tok.value); | |
707 | ||
708 | if (GSS_ERROR(status)) { | |
709 | /* Start again with the next method in the list */ | |
710 | userauth(authctxt, NULL); | |
711 | return; | |
712 | } | |
713 | } | |
714 | ||
715 | /* ARGSUSED */ | |
716 | void | |
717 | input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) | |
718 | { | |
719 | Authctxt *authctxt = ctxt; | |
720 | Gssctxt *gssctxt; | |
721 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | |
722 | gss_buffer_desc recv_tok; | |
723 | OM_uint32 status, ms; | |
724 | u_int len; | |
725 | ||
726 | if (authctxt == NULL) | |
727 | fatal("input_gssapi_response: no authentication context"); | |
728 | gssctxt = authctxt->methoddata; | |
729 | ||
730 | recv_tok.value = packet_get_string(&len); | |
731 | recv_tok.length = len; | |
732 | ||
733 | packet_check_eom(); | |
734 | ||
735 | /* Stick it into GSSAPI and see what it says */ | |
736 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, | |
737 | &recv_tok, &send_tok, NULL); | |
738 | ||
739 | xfree(recv_tok.value); | |
740 | gss_release_buffer(&ms, &send_tok); | |
741 | ||
742 | /* Server will be returning a failed packet after this one */ | |
743 | } | |
744 | ||
745 | /* ARGSUSED */ | |
746 | void | |
747 | input_gssapi_error(int type, u_int32_t plen, void *ctxt) | |
748 | { | |
749 | OM_uint32 maj, min; | |
750 | char *msg; | |
751 | char *lang; | |
752 | ||
753 | maj=packet_get_int(); | |
754 | min=packet_get_int(); | |
755 | msg=packet_get_string(NULL); | |
756 | lang=packet_get_string(NULL); | |
757 | ||
758 | packet_check_eom(); | |
759 | ||
760 | debug("Server GSSAPI Error:\n%s", msg); | |
761 | xfree(msg); | |
762 | xfree(lang); | |
763 | } | |
764 | #endif /* GSSAPI */ | |
765 | ||
766 | int | |
767 | userauth_none(Authctxt *authctxt) | |
768 | { | |
769 | /* initial userauth request */ | |
770 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
771 | packet_put_cstring(authctxt->server_user); | |
772 | packet_put_cstring(authctxt->service); | |
773 | packet_put_cstring(authctxt->method->name); | |
774 | packet_send(); | |
775 | return 1; | |
776 | } | |
777 | ||
778 | int | |
779 | userauth_passwd(Authctxt *authctxt) | |
780 | { | |
781 | static int attempt = 0; | |
782 | char prompt[150]; | |
783 | char *password; | |
784 | ||
785 | if (attempt++ >= options.number_of_password_prompts) | |
786 | return 0; | |
787 | ||
788 | if (attempt != 1) | |
789 | error("Permission denied, please try again."); | |
790 | ||
791 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", | |
792 | authctxt->server_user, authctxt->host); | |
793 | password = read_passphrase(prompt, 0); | |
794 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
795 | packet_put_cstring(authctxt->server_user); | |
796 | packet_put_cstring(authctxt->service); | |
797 | packet_put_cstring(authctxt->method->name); | |
798 | packet_put_char(0); | |
799 | packet_put_cstring(password); | |
800 | memset(password, 0, strlen(password)); | |
801 | xfree(password); | |
802 | packet_add_padding(64); | |
803 | packet_send(); | |
804 | ||
805 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, | |
806 | &input_userauth_passwd_changereq); | |
807 | ||
808 | return 1; | |
809 | } | |
810 | ||
811 | /* | |
812 | * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST | |
813 | */ | |
814 | /* ARGSUSED */ | |
815 | void | |
816 | input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) | |
817 | { | |
818 | Authctxt *authctxt = ctxt; | |
819 | char *info, *lang, *password = NULL, *retype = NULL; | |
820 | char prompt[150]; | |
821 | ||
822 | debug2("input_userauth_passwd_changereq"); | |
823 | ||
824 | if (authctxt == NULL) | |
825 | fatal("input_userauth_passwd_changereq: " | |
826 | "no authentication context"); | |
827 | ||
828 | info = packet_get_string(NULL); | |
829 | lang = packet_get_string(NULL); | |
830 | if (strlen(info) > 0) | |
831 | logit("%s", info); | |
832 | xfree(info); | |
833 | xfree(lang); | |
834 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
835 | packet_put_cstring(authctxt->server_user); | |
836 | packet_put_cstring(authctxt->service); | |
837 | packet_put_cstring(authctxt->method->name); | |
838 | packet_put_char(1); /* additional info */ | |
839 | snprintf(prompt, sizeof(prompt), | |
840 | "Enter %.30s@%.128s's old password: ", | |
841 | authctxt->server_user, authctxt->host); | |
842 | password = read_passphrase(prompt, 0); | |
843 | packet_put_cstring(password); | |
844 | memset(password, 0, strlen(password)); | |
845 | xfree(password); | |
846 | password = NULL; | |
847 | while (password == NULL) { | |
848 | snprintf(prompt, sizeof(prompt), | |
849 | "Enter %.30s@%.128s's new password: ", | |
850 | authctxt->server_user, authctxt->host); | |
851 | password = read_passphrase(prompt, RP_ALLOW_EOF); | |
852 | if (password == NULL) { | |
853 | /* bail out */ | |
854 | return; | |
855 | } | |
856 | snprintf(prompt, sizeof(prompt), | |
857 | "Retype %.30s@%.128s's new password: ", | |
858 | authctxt->server_user, authctxt->host); | |
859 | retype = read_passphrase(prompt, 0); | |
860 | if (strcmp(password, retype) != 0) { | |
861 | memset(password, 0, strlen(password)); | |
862 | xfree(password); | |
863 | logit("Mismatch; try again, EOF to quit."); | |
864 | password = NULL; | |
865 | } | |
866 | memset(retype, 0, strlen(retype)); | |
867 | xfree(retype); | |
868 | } | |
869 | packet_put_cstring(password); | |
870 | memset(password, 0, strlen(password)); | |
871 | xfree(password); | |
872 | packet_add_padding(64); | |
873 | packet_send(); | |
874 | ||
875 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, | |
876 | &input_userauth_passwd_changereq); | |
877 | } | |
878 | ||
879 | #ifdef JPAKE | |
880 | static char * | |
881 | pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) | |
882 | { | |
883 | /* OpenBSD crypt(3) handles all of these */ | |
884 | if (strcmp(crypt_scheme, "crypt") == 0 || | |
885 | strcmp(crypt_scheme, "bcrypt") == 0 || | |
886 | strcmp(crypt_scheme, "md5crypt") == 0 || | |
887 | strcmp(crypt_scheme, "crypt-extended") == 0) | |
888 | return xstrdup(crypt(password, salt)); | |
889 | error("%s: unsupported password encryption scheme \"%.100s\"", | |
890 | __func__, crypt_scheme); | |
891 | return NULL; | |
892 | } | |
893 | ||
894 | static BIGNUM * | |
895 | jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, | |
896 | const char *salt) | |
897 | { | |
898 | char prompt[256], *password, *crypted; | |
899 | u_char *secret; | |
900 | u_int secret_len; | |
901 | BIGNUM *ret; | |
902 | ||
903 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", | |
904 | authctxt->server_user, authctxt->host); | |
905 | password = read_passphrase(prompt, 0); | |
906 | ||
907 | if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { | |
908 | logit("Disabling %s authentication", authctxt->method->name); | |
909 | authctxt->method->enabled = NULL; | |
910 | /* Continue with an empty password to fail gracefully */ | |
911 | crypted = xstrdup(""); | |
912 | } | |
913 | ||
914 | #ifdef JPAKE_DEBUG | |
915 | debug3("%s: salt = %s", __func__, salt); | |
916 | debug3("%s: scheme = %s", __func__, crypt_scheme); | |
917 | debug3("%s: crypted = %s", __func__, crypted); | |
918 | #endif | |
919 | ||
920 | if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), | |
921 | &secret, &secret_len) != 0) | |
922 | fatal("%s: hash_buffer", __func__); | |
923 | ||
924 | bzero(password, strlen(password)); | |
925 | bzero(crypted, strlen(crypted)); | |
926 | xfree(password); | |
927 | xfree(crypted); | |
928 | ||
929 | if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) | |
930 | fatal("%s: BN_bin2bn (secret)", __func__); | |
931 | bzero(secret, secret_len); | |
932 | xfree(secret); | |
933 | ||
934 | return ret; | |
935 | } | |
936 | ||
937 | /* ARGSUSED */ | |
938 | void | |
939 | input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) | |
940 | { | |
941 | Authctxt *authctxt = ctxt; | |
942 | struct jpake_ctx *pctx = authctxt->methoddata; | |
943 | u_char *x3_proof, *x4_proof, *x2_s_proof; | |
944 | u_int x3_proof_len, x4_proof_len, x2_s_proof_len; | |
945 | char *crypt_scheme, *salt; | |
946 | ||
947 | /* Disable this message */ | |
948 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); | |
949 | ||
950 | if ((pctx->g_x3 = BN_new()) == NULL || | |
951 | (pctx->g_x4 = BN_new()) == NULL) | |
952 | fatal("%s: BN_new", __func__); | |
953 | ||
954 | /* Fetch step 1 values */ | |
955 | crypt_scheme = packet_get_string(NULL); | |
956 | salt = packet_get_string(NULL); | |
957 | pctx->server_id = packet_get_string(&pctx->server_id_len); | |
958 | packet_get_bignum2(pctx->g_x3); | |
959 | packet_get_bignum2(pctx->g_x4); | |
960 | x3_proof = packet_get_string(&x3_proof_len); | |
961 | x4_proof = packet_get_string(&x4_proof_len); | |
962 | packet_check_eom(); | |
963 | ||
964 | JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); | |
965 | ||
966 | /* Obtain password and derive secret */ | |
967 | pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); | |
968 | bzero(crypt_scheme, strlen(crypt_scheme)); | |
969 | bzero(salt, strlen(salt)); | |
970 | xfree(crypt_scheme); | |
971 | xfree(salt); | |
972 | JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); | |
973 | ||
974 | /* Calculate step 2 values */ | |
975 | jpake_step2(pctx->grp, pctx->s, pctx->g_x1, | |
976 | pctx->g_x3, pctx->g_x4, pctx->x2, | |
977 | pctx->server_id, pctx->server_id_len, | |
978 | pctx->client_id, pctx->client_id_len, | |
979 | x3_proof, x3_proof_len, | |
980 | x4_proof, x4_proof_len, | |
981 | &pctx->a, | |
982 | &x2_s_proof, &x2_s_proof_len); | |
983 | ||
984 | bzero(x3_proof, x3_proof_len); | |
985 | bzero(x4_proof, x4_proof_len); | |
986 | xfree(x3_proof); | |
987 | xfree(x4_proof); | |
988 | ||
989 | JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); | |
990 | ||
991 | /* Send values for step 2 */ | |
992 | packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); | |
993 | packet_put_bignum2(pctx->a); | |
994 | packet_put_string(x2_s_proof, x2_s_proof_len); | |
995 | packet_send(); | |
996 | ||
997 | bzero(x2_s_proof, x2_s_proof_len); | |
998 | xfree(x2_s_proof); | |
999 | ||
1000 | /* Expect step 2 packet from peer */ | |
1001 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, | |
1002 | input_userauth_jpake_server_step2); | |
1003 | } | |
1004 | ||
1005 | /* ARGSUSED */ | |
1006 | void | |
1007 | input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) | |
1008 | { | |
1009 | Authctxt *authctxt = ctxt; | |
1010 | struct jpake_ctx *pctx = authctxt->methoddata; | |
1011 | u_char *x4_s_proof; | |
1012 | u_int x4_s_proof_len; | |
1013 | ||
1014 | /* Disable this message */ | |
1015 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); | |
1016 | ||
1017 | if ((pctx->b = BN_new()) == NULL) | |
1018 | fatal("%s: BN_new", __func__); | |
1019 | ||
1020 | /* Fetch step 2 values */ | |
1021 | packet_get_bignum2(pctx->b); | |
1022 | x4_s_proof = packet_get_string(&x4_s_proof_len); | |
1023 | packet_check_eom(); | |
1024 | ||
1025 | JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); | |
1026 | ||
1027 | /* Derive shared key and calculate confirmation hash */ | |
1028 | jpake_key_confirm(pctx->grp, pctx->s, pctx->b, | |
1029 | pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, | |
1030 | pctx->client_id, pctx->client_id_len, | |
1031 | pctx->server_id, pctx->server_id_len, | |
1032 | session_id2, session_id2_len, | |
1033 | x4_s_proof, x4_s_proof_len, | |
1034 | &pctx->k, | |
1035 | &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); | |
1036 | ||
1037 | bzero(x4_s_proof, x4_s_proof_len); | |
1038 | xfree(x4_s_proof); | |
1039 | ||
1040 | JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); | |
1041 | ||
1042 | /* Send key confirmation proof */ | |
1043 | packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); | |
1044 | packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); | |
1045 | packet_send(); | |
1046 | ||
1047 | /* Expect confirmation from peer */ | |
1048 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, | |
1049 | input_userauth_jpake_server_confirm); | |
1050 | } | |
1051 | ||
1052 | /* ARGSUSED */ | |
1053 | void | |
1054 | input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) | |
1055 | { | |
1056 | Authctxt *authctxt = ctxt; | |
1057 | struct jpake_ctx *pctx = authctxt->methoddata; | |
1058 | ||
1059 | /* Disable this message */ | |
1060 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); | |
1061 | ||
1062 | pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); | |
1063 | packet_check_eom(); | |
1064 | ||
1065 | JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); | |
1066 | ||
1067 | /* Verify expected confirmation hash */ | |
1068 | if (jpake_check_confirm(pctx->k, | |
1069 | pctx->server_id, pctx->server_id_len, | |
1070 | session_id2, session_id2_len, | |
1071 | pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) | |
1072 | debug("%s: %s success", __func__, authctxt->method->name); | |
1073 | else { | |
1074 | debug("%s: confirmation mismatch", __func__); | |
1075 | /* XXX stash this so if auth succeeds then we can warn/kill */ | |
1076 | } | |
1077 | ||
1078 | userauth_jpake_cleanup(authctxt); | |
1079 | } | |
1080 | #endif /* JPAKE */ | |
1081 | ||
1082 | static int | |
1083 | identity_sign(Identity *id, u_char **sigp, u_int *lenp, | |
1084 | u_char *data, u_int datalen) | |
1085 | { | |
1086 | Key *prv; | |
1087 | int ret; | |
1088 | ||
1089 | /* the agent supports this key */ | |
1090 | if (id->ac) | |
1091 | return (ssh_agent_sign(id->ac, id->key, sigp, lenp, | |
1092 | data, datalen)); | |
1093 | /* | |
1094 | * we have already loaded the private key or | |
1095 | * the private key is stored in external hardware | |
1096 | */ | |
1097 | if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) | |
1098 | return (key_sign(id->key, sigp, lenp, data, datalen)); | |
1099 | /* load the private key from the file */ | |
1100 | if ((prv = load_identity_file(id->filename)) == NULL) | |
1101 | return (-1); | |
1102 | ret = key_sign(prv, sigp, lenp, data, datalen); | |
1103 | key_free(prv); | |
1104 | return (ret); | |
1105 | } | |
1106 | ||
1107 | static int | |
1108 | sign_and_send_pubkey(Authctxt *authctxt, Identity *id) | |
1109 | { | |
1110 | Buffer b; | |
1111 | u_char *blob, *signature; | |
1112 | u_int bloblen, slen; | |
1113 | u_int skip = 0; | |
1114 | int ret = -1; | |
1115 | int have_sig = 1; | |
1116 | ||
1117 | debug3("sign_and_send_pubkey"); | |
1118 | ||
1119 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { | |
1120 | /* we cannot handle this key */ | |
1121 | debug3("sign_and_send_pubkey: cannot handle key"); | |
1122 | return 0; | |
1123 | } | |
1124 | /* data to be signed */ | |
1125 | buffer_init(&b); | |
1126 | if (datafellows & SSH_OLD_SESSIONID) { | |
1127 | buffer_append(&b, session_id2, session_id2_len); | |
1128 | skip = session_id2_len; | |
1129 | } else { | |
1130 | buffer_put_string(&b, session_id2, session_id2_len); | |
1131 | skip = buffer_len(&b); | |
1132 | } | |
1133 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
1134 | buffer_put_cstring(&b, authctxt->server_user); | |
1135 | buffer_put_cstring(&b, | |
1136 | datafellows & SSH_BUG_PKSERVICE ? | |
1137 | "ssh-userauth" : | |
1138 | authctxt->service); | |
1139 | if (datafellows & SSH_BUG_PKAUTH) { | |
1140 | buffer_put_char(&b, have_sig); | |
1141 | } else { | |
1142 | buffer_put_cstring(&b, authctxt->method->name); | |
1143 | buffer_put_char(&b, have_sig); | |
1144 | buffer_put_cstring(&b, key_ssh_name(id->key)); | |
1145 | } | |
1146 | buffer_put_string(&b, blob, bloblen); | |
1147 | ||
1148 | /* generate signature */ | |
1149 | ret = identity_sign(id, &signature, &slen, | |
1150 | buffer_ptr(&b), buffer_len(&b)); | |
1151 | if (ret == -1) { | |
1152 | xfree(blob); | |
1153 | buffer_free(&b); | |
1154 | return 0; | |
1155 | } | |
1156 | #ifdef DEBUG_PK | |
1157 | buffer_dump(&b); | |
1158 | #endif | |
1159 | if (datafellows & SSH_BUG_PKSERVICE) { | |
1160 | buffer_clear(&b); | |
1161 | buffer_append(&b, session_id2, session_id2_len); | |
1162 | skip = session_id2_len; | |
1163 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
1164 | buffer_put_cstring(&b, authctxt->server_user); | |
1165 | buffer_put_cstring(&b, authctxt->service); | |
1166 | buffer_put_cstring(&b, authctxt->method->name); | |
1167 | buffer_put_char(&b, have_sig); | |
1168 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
1169 | buffer_put_cstring(&b, key_ssh_name(id->key)); | |
1170 | buffer_put_string(&b, blob, bloblen); | |
1171 | } | |
1172 | xfree(blob); | |
1173 | ||
1174 | /* append signature */ | |
1175 | buffer_put_string(&b, signature, slen); | |
1176 | xfree(signature); | |
1177 | ||
1178 | /* skip session id and packet type */ | |
1179 | if (buffer_len(&b) < skip + 1) | |
1180 | fatal("userauth_pubkey: internal error"); | |
1181 | buffer_consume(&b, skip + 1); | |
1182 | ||
1183 | /* put remaining data from buffer into packet */ | |
1184 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1185 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
1186 | buffer_free(&b); | |
1187 | packet_send(); | |
1188 | ||
1189 | return 1; | |
1190 | } | |
1191 | ||
1192 | static int | |
1193 | send_pubkey_test(Authctxt *authctxt, Identity *id) | |
1194 | { | |
1195 | u_char *blob; | |
1196 | u_int bloblen, have_sig = 0; | |
1197 | ||
1198 | debug3("send_pubkey_test"); | |
1199 | ||
1200 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { | |
1201 | /* we cannot handle this key */ | |
1202 | debug3("send_pubkey_test: cannot handle key"); | |
1203 | return 0; | |
1204 | } | |
1205 | /* register callback for USERAUTH_PK_OK message */ | |
1206 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
1207 | ||
1208 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1209 | packet_put_cstring(authctxt->server_user); | |
1210 | packet_put_cstring(authctxt->service); | |
1211 | packet_put_cstring(authctxt->method->name); | |
1212 | packet_put_char(have_sig); | |
1213 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
1214 | packet_put_cstring(key_ssh_name(id->key)); | |
1215 | packet_put_string(blob, bloblen); | |
1216 | xfree(blob); | |
1217 | packet_send(); | |
1218 | return 1; | |
1219 | } | |
1220 | ||
1221 | static Key * | |
1222 | load_identity_file(char *filename) | |
1223 | { | |
1224 | Key *private; | |
1225 | char prompt[300], *passphrase; | |
1226 | int perm_ok, quit, i; | |
1227 | struct stat st; | |
1228 | ||
1229 | if (stat(filename, &st) < 0) { | |
1230 | debug3("no such identity: %s", filename); | |
1231 | return NULL; | |
1232 | } | |
1233 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); | |
1234 | if (!perm_ok) | |
1235 | return NULL; | |
1236 | if (private == NULL) { | |
1237 | if (options.batch_mode) | |
1238 | return NULL; | |
1239 | snprintf(prompt, sizeof prompt, | |
1240 | "Enter passphrase for key '%.100s': ", filename); | |
1241 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
1242 | passphrase = read_passphrase(prompt, 0); | |
1243 | if (strcmp(passphrase, "") != 0) { | |
1244 | private = key_load_private_type(KEY_UNSPEC, | |
1245 | filename, passphrase, NULL, NULL); | |
1246 | quit = 0; | |
1247 | } else { | |
1248 | debug2("no passphrase given, try next key"); | |
1249 | quit = 1; | |
1250 | } | |
1251 | memset(passphrase, 0, strlen(passphrase)); | |
1252 | xfree(passphrase); | |
1253 | if (private != NULL || quit) | |
1254 | break; | |
1255 | debug2("bad passphrase given, try again..."); | |
1256 | } | |
1257 | } | |
1258 | return private; | |
1259 | } | |
1260 | ||
1261 | /* | |
1262 | * try keys in the following order: | |
1263 | * 1. agent keys that are found in the config file | |
1264 | * 2. other agent keys | |
1265 | * 3. keys that are only listed in the config file | |
1266 | */ | |
1267 | static void | |
1268 | pubkey_prepare(Authctxt *authctxt) | |
1269 | { | |
1270 | Identity *id; | |
1271 | Idlist agent, files, *preferred; | |
1272 | Key *key; | |
1273 | AuthenticationConnection *ac; | |
1274 | char *comment; | |
1275 | int i, found; | |
1276 | ||
1277 | TAILQ_INIT(&agent); /* keys from the agent */ | |
1278 | TAILQ_INIT(&files); /* keys from the config file */ | |
1279 | preferred = &authctxt->keys; | |
1280 | TAILQ_INIT(preferred); /* preferred order of keys */ | |
1281 | ||
1282 | /* list of keys stored in the filesystem */ | |
1283 | for (i = 0; i < options.num_identity_files; i++) { | |
1284 | key = options.identity_keys[i]; | |
1285 | if (key && key->type == KEY_RSA1) | |
1286 | continue; | |
1287 | options.identity_keys[i] = NULL; | |
1288 | id = xcalloc(1, sizeof(*id)); | |
1289 | id->key = key; | |
1290 | id->filename = xstrdup(options.identity_files[i]); | |
1291 | TAILQ_INSERT_TAIL(&files, id, next); | |
1292 | } | |
1293 | /* list of keys supported by the agent */ | |
1294 | if ((ac = ssh_get_authentication_connection())) { | |
1295 | for (key = ssh_get_first_identity(ac, &comment, 2); | |
1296 | key != NULL; | |
1297 | key = ssh_get_next_identity(ac, &comment, 2)) { | |
1298 | found = 0; | |
1299 | TAILQ_FOREACH(id, &files, next) { | |
1300 | /* agent keys from the config file are preferred */ | |
1301 | if (key_equal(key, id->key)) { | |
1302 | key_free(key); | |
1303 | xfree(comment); | |
1304 | TAILQ_REMOVE(&files, id, next); | |
1305 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1306 | id->ac = ac; | |
1307 | found = 1; | |
1308 | break; | |
1309 | } | |
1310 | } | |
1311 | if (!found && !options.identities_only) { | |
1312 | id = xcalloc(1, sizeof(*id)); | |
1313 | id->key = key; | |
1314 | id->filename = comment; | |
1315 | id->ac = ac; | |
1316 | TAILQ_INSERT_TAIL(&agent, id, next); | |
1317 | } | |
1318 | } | |
1319 | /* append remaining agent keys */ | |
1320 | for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { | |
1321 | TAILQ_REMOVE(&agent, id, next); | |
1322 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1323 | } | |
1324 | authctxt->agent = ac; | |
1325 | } | |
1326 | /* append remaining keys from the config file */ | |
1327 | for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { | |
1328 | TAILQ_REMOVE(&files, id, next); | |
1329 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1330 | } | |
1331 | TAILQ_FOREACH(id, preferred, next) { | |
1332 | debug2("key: %s (%p)", id->filename, id->key); | |
1333 | } | |
1334 | } | |
1335 | ||
1336 | static void | |
1337 | pubkey_cleanup(Authctxt *authctxt) | |
1338 | { | |
1339 | Identity *id; | |
1340 | ||
1341 | if (authctxt->agent != NULL) | |
1342 | ssh_close_authentication_connection(authctxt->agent); | |
1343 | for (id = TAILQ_FIRST(&authctxt->keys); id; | |
1344 | id = TAILQ_FIRST(&authctxt->keys)) { | |
1345 | TAILQ_REMOVE(&authctxt->keys, id, next); | |
1346 | if (id->key) | |
1347 | key_free(id->key); | |
1348 | if (id->filename) | |
1349 | xfree(id->filename); | |
1350 | xfree(id); | |
1351 | } | |
1352 | } | |
1353 | ||
1354 | int | |
1355 | userauth_pubkey(Authctxt *authctxt) | |
1356 | { | |
1357 | Identity *id; | |
1358 | int sent = 0; | |
1359 | ||
1360 | while ((id = TAILQ_FIRST(&authctxt->keys))) { | |
1361 | if (id->tried++) | |
1362 | return (0); | |
1363 | /* move key to the end of the queue */ | |
1364 | TAILQ_REMOVE(&authctxt->keys, id, next); | |
1365 | TAILQ_INSERT_TAIL(&authctxt->keys, id, next); | |
1366 | /* | |
1367 | * send a test message if we have the public key. for | |
1368 | * encrypted keys we cannot do this and have to load the | |
1369 | * private key instead | |
1370 | */ | |
1371 | if (id->key && id->key->type != KEY_RSA1) { | |
1372 | debug("Offering public key: %s", id->filename); | |
1373 | sent = send_pubkey_test(authctxt, id); | |
1374 | } else if (id->key == NULL) { | |
1375 | debug("Trying private key: %s", id->filename); | |
1376 | id->key = load_identity_file(id->filename); | |
1377 | if (id->key != NULL) { | |
1378 | id->isprivate = 1; | |
1379 | sent = sign_and_send_pubkey(authctxt, id); | |
1380 | key_free(id->key); | |
1381 | id->key = NULL; | |
1382 | } | |
1383 | } | |
1384 | if (sent) | |
1385 | return (sent); | |
1386 | } | |
1387 | return (0); | |
1388 | } | |
1389 | ||
1390 | /* | |
1391 | * Send userauth request message specifying keyboard-interactive method. | |
1392 | */ | |
1393 | int | |
1394 | userauth_kbdint(Authctxt *authctxt) | |
1395 | { | |
1396 | static int attempt = 0; | |
1397 | ||
1398 | if (attempt++ >= options.number_of_password_prompts) | |
1399 | return 0; | |
1400 | /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ | |
1401 | if (attempt > 1 && !authctxt->info_req_seen) { | |
1402 | debug3("userauth_kbdint: disable: no info_req_seen"); | |
1403 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); | |
1404 | return 0; | |
1405 | } | |
1406 | ||
1407 | debug2("userauth_kbdint"); | |
1408 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1409 | packet_put_cstring(authctxt->server_user); | |
1410 | packet_put_cstring(authctxt->service); | |
1411 | packet_put_cstring(authctxt->method->name); | |
1412 | packet_put_cstring(""); /* lang */ | |
1413 | packet_put_cstring(options.kbd_interactive_devices ? | |
1414 | options.kbd_interactive_devices : ""); | |
1415 | packet_send(); | |
1416 | ||
1417 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1418 | return 1; | |
1419 | } | |
1420 | ||
1421 | /* | |
1422 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE | |
1423 | */ | |
1424 | void | |
1425 | input_userauth_info_req(int type, u_int32_t seq, void *ctxt) | |
1426 | { | |
1427 | Authctxt *authctxt = ctxt; | |
1428 | char *name, *inst, *lang, *prompt, *response; | |
1429 | u_int num_prompts, i; | |
1430 | int echo = 0; | |
1431 | ||
1432 | debug2("input_userauth_info_req"); | |
1433 | ||
1434 | if (authctxt == NULL) | |
1435 | fatal("input_userauth_info_req: no authentication context"); | |
1436 | ||
1437 | authctxt->info_req_seen = 1; | |
1438 | ||
1439 | name = packet_get_string(NULL); | |
1440 | inst = packet_get_string(NULL); | |
1441 | lang = packet_get_string(NULL); | |
1442 | if (strlen(name) > 0) | |
1443 | logit("%s", name); | |
1444 | if (strlen(inst) > 0) | |
1445 | logit("%s", inst); | |
1446 | xfree(name); | |
1447 | xfree(inst); | |
1448 | xfree(lang); | |
1449 | ||
1450 | num_prompts = packet_get_int(); | |
1451 | /* | |
1452 | * Begin to build info response packet based on prompts requested. | |
1453 | * We commit to providing the correct number of responses, so if | |
1454 | * further on we run into a problem that prevents this, we have to | |
1455 | * be sure and clean this up and send a correct error response. | |
1456 | */ | |
1457 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1458 | packet_put_int(num_prompts); | |
1459 | ||
1460 | debug2("input_userauth_info_req: num_prompts %d", num_prompts); | |
1461 | for (i = 0; i < num_prompts; i++) { | |
1462 | prompt = packet_get_string(NULL); | |
1463 | echo = packet_get_char(); | |
1464 | ||
1465 | response = read_passphrase(prompt, echo ? RP_ECHO : 0); | |
1466 | ||
1467 | packet_put_cstring(response); | |
1468 | memset(response, 0, strlen(response)); | |
1469 | xfree(response); | |
1470 | xfree(prompt); | |
1471 | } | |
1472 | packet_check_eom(); /* done with parsing incoming message. */ | |
1473 | ||
1474 | packet_add_padding(64); | |
1475 | packet_send(); | |
1476 | } | |
1477 | ||
1478 | static int | |
1479 | ssh_keysign(Key *key, u_char **sigp, u_int *lenp, | |
1480 | u_char *data, u_int datalen) | |
1481 | { | |
1482 | Buffer b; | |
1483 | struct stat st; | |
1484 | pid_t pid; | |
1485 | int to[2], from[2], status, version = 2; | |
1486 | ||
1487 | debug2("ssh_keysign called"); | |
1488 | ||
1489 | if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { | |
1490 | error("ssh_keysign: no installed: %s", strerror(errno)); | |
1491 | return -1; | |
1492 | } | |
1493 | if (fflush(stdout) != 0) | |
1494 | error("ssh_keysign: fflush: %s", strerror(errno)); | |
1495 | if (pipe(to) < 0) { | |
1496 | error("ssh_keysign: pipe: %s", strerror(errno)); | |
1497 | return -1; | |
1498 | } | |
1499 | if (pipe(from) < 0) { | |
1500 | error("ssh_keysign: pipe: %s", strerror(errno)); | |
1501 | return -1; | |
1502 | } | |
1503 | if ((pid = fork()) < 0) { | |
1504 | error("ssh_keysign: fork: %s", strerror(errno)); | |
1505 | return -1; | |
1506 | } | |
1507 | if (pid == 0) { | |
1508 | permanently_drop_suid(getuid()); | |
1509 | close(from[0]); | |
1510 | if (dup2(from[1], STDOUT_FILENO) < 0) | |
1511 | fatal("ssh_keysign: dup2: %s", strerror(errno)); | |
1512 | close(to[1]); | |
1513 | if (dup2(to[0], STDIN_FILENO) < 0) | |
1514 | fatal("ssh_keysign: dup2: %s", strerror(errno)); | |
1515 | close(from[1]); | |
1516 | close(to[0]); | |
1517 | execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); | |
1518 | fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, | |
1519 | strerror(errno)); | |
1520 | } | |
1521 | close(from[1]); | |
1522 | close(to[0]); | |
1523 | ||
1524 | buffer_init(&b); | |
1525 | buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ | |
1526 | buffer_put_string(&b, data, datalen); | |
1527 | if (ssh_msg_send(to[1], version, &b) == -1) | |
1528 | fatal("ssh_keysign: couldn't send request"); | |
1529 | ||
1530 | if (ssh_msg_recv(from[0], &b) < 0) { | |
1531 | error("ssh_keysign: no reply"); | |
1532 | buffer_free(&b); | |
1533 | return -1; | |
1534 | } | |
1535 | close(from[0]); | |
1536 | close(to[1]); | |
1537 | ||
1538 | while (waitpid(pid, &status, 0) < 0) | |
1539 | if (errno != EINTR) | |
1540 | break; | |
1541 | ||
1542 | if (buffer_get_char(&b) != version) { | |
1543 | error("ssh_keysign: bad version"); | |
1544 | buffer_free(&b); | |
1545 | return -1; | |
1546 | } | |
1547 | *sigp = buffer_get_string(&b, lenp); | |
1548 | buffer_free(&b); | |
1549 | ||
1550 | return 0; | |
1551 | } | |
1552 | ||
1553 | int | |
1554 | userauth_hostbased(Authctxt *authctxt) | |
1555 | { | |
1556 | Key *private = NULL; | |
1557 | Sensitive *sensitive = authctxt->sensitive; | |
1558 | Buffer b; | |
1559 | u_char *signature, *blob; | |
1560 | char *chost, *pkalg, *p, myname[NI_MAXHOST]; | |
1561 | const char *service; | |
1562 | u_int blen, slen; | |
1563 | int ok, i, len, found = 0; | |
1564 | ||
1565 | /* check for a useful key */ | |
1566 | for (i = 0; i < sensitive->nkeys; i++) { | |
1567 | private = sensitive->keys[i]; | |
1568 | if (private && private->type != KEY_RSA1) { | |
1569 | found = 1; | |
1570 | /* we take and free the key */ | |
1571 | sensitive->keys[i] = NULL; | |
1572 | break; | |
1573 | } | |
1574 | } | |
1575 | if (!found) { | |
1576 | debug("No more client hostkeys for hostbased authentication."); | |
1577 | return 0; | |
1578 | } | |
1579 | if (key_to_blob(private, &blob, &blen) == 0) { | |
1580 | key_free(private); | |
1581 | return 0; | |
1582 | } | |
1583 | /* figure out a name for the client host */ | |
1584 | p = NULL; | |
1585 | if (packet_connection_is_on_socket()) | |
1586 | p = get_local_name(packet_get_connection_in()); | |
1587 | if (p == NULL) { | |
1588 | if (gethostname(myname, sizeof(myname)) == -1) { | |
1589 | verbose("userauth_hostbased: gethostname: %s", | |
1590 | strerror(errno)); | |
1591 | } else | |
1592 | p = xstrdup(myname); | |
1593 | } | |
1594 | if (p == NULL) { | |
1595 | error("userauth_hostbased: cannot get local ipaddr/name"); | |
1596 | key_free(private); | |
1597 | xfree(blob); | |
1598 | return 0; | |
1599 | } | |
1600 | len = strlen(p) + 2; | |
1601 | xasprintf(&chost, "%s.", p); | |
1602 | debug2("userauth_hostbased: chost %s", chost); | |
1603 | xfree(p); | |
1604 | ||
1605 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : | |
1606 | authctxt->service; | |
1607 | pkalg = xstrdup(key_ssh_name(private)); | |
1608 | buffer_init(&b); | |
1609 | /* construct data */ | |
1610 | buffer_put_string(&b, session_id2, session_id2_len); | |
1611 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
1612 | buffer_put_cstring(&b, authctxt->server_user); | |
1613 | buffer_put_cstring(&b, service); | |
1614 | buffer_put_cstring(&b, authctxt->method->name); | |
1615 | buffer_put_cstring(&b, pkalg); | |
1616 | buffer_put_string(&b, blob, blen); | |
1617 | buffer_put_cstring(&b, chost); | |
1618 | buffer_put_cstring(&b, authctxt->local_user); | |
1619 | #ifdef DEBUG_PK | |
1620 | buffer_dump(&b); | |
1621 | #endif | |
1622 | if (sensitive->external_keysign) | |
1623 | ok = ssh_keysign(private, &signature, &slen, | |
1624 | buffer_ptr(&b), buffer_len(&b)); | |
1625 | else | |
1626 | ok = key_sign(private, &signature, &slen, | |
1627 | buffer_ptr(&b), buffer_len(&b)); | |
1628 | key_free(private); | |
1629 | buffer_free(&b); | |
1630 | if (ok != 0) { | |
1631 | error("key_sign failed"); | |
1632 | xfree(chost); | |
1633 | xfree(pkalg); | |
1634 | xfree(blob); | |
1635 | return 0; | |
1636 | } | |
1637 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1638 | packet_put_cstring(authctxt->server_user); | |
1639 | packet_put_cstring(authctxt->service); | |
1640 | packet_put_cstring(authctxt->method->name); | |
1641 | packet_put_cstring(pkalg); | |
1642 | packet_put_string(blob, blen); | |
1643 | packet_put_cstring(chost); | |
1644 | packet_put_cstring(authctxt->local_user); | |
1645 | packet_put_string(signature, slen); | |
1646 | memset(signature, 's', slen); | |
1647 | xfree(signature); | |
1648 | xfree(chost); | |
1649 | xfree(pkalg); | |
1650 | xfree(blob); | |
1651 | ||
1652 | packet_send(); | |
1653 | return 1; | |
1654 | } | |
1655 | ||
1656 | #ifdef JPAKE | |
1657 | int | |
1658 | userauth_jpake(Authctxt *authctxt) | |
1659 | { | |
1660 | struct jpake_ctx *pctx; | |
1661 | u_char *x1_proof, *x2_proof; | |
1662 | u_int x1_proof_len, x2_proof_len; | |
1663 | static int attempt = 0; /* XXX share with userauth_password's? */ | |
1664 | ||
1665 | if (attempt++ >= options.number_of_password_prompts) | |
1666 | return 0; | |
1667 | if (attempt != 1) | |
1668 | error("Permission denied, please try again."); | |
1669 | ||
1670 | if (authctxt->methoddata != NULL) | |
1671 | fatal("%s: authctxt->methoddata already set (%p)", | |
1672 | __func__, authctxt->methoddata); | |
1673 | ||
1674 | authctxt->methoddata = pctx = jpake_new(); | |
1675 | ||
1676 | /* | |
1677 | * Send request immediately, to get the protocol going while | |
1678 | * we do the initial computations. | |
1679 | */ | |
1680 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1681 | packet_put_cstring(authctxt->server_user); | |
1682 | packet_put_cstring(authctxt->service); | |
1683 | packet_put_cstring(authctxt->method->name); | |
1684 | packet_send(); | |
1685 | packet_write_wait(); | |
1686 | ||
1687 | jpake_step1(pctx->grp, | |
1688 | &pctx->client_id, &pctx->client_id_len, | |
1689 | &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, | |
1690 | &x1_proof, &x1_proof_len, | |
1691 | &x2_proof, &x2_proof_len); | |
1692 | ||
1693 | JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); | |
1694 | ||
1695 | packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); | |
1696 | packet_put_string(pctx->client_id, pctx->client_id_len); | |
1697 | packet_put_bignum2(pctx->g_x1); | |
1698 | packet_put_bignum2(pctx->g_x2); | |
1699 | packet_put_string(x1_proof, x1_proof_len); | |
1700 | packet_put_string(x2_proof, x2_proof_len); | |
1701 | packet_send(); | |
1702 | ||
1703 | bzero(x1_proof, x1_proof_len); | |
1704 | bzero(x2_proof, x2_proof_len); | |
1705 | xfree(x1_proof); | |
1706 | xfree(x2_proof); | |
1707 | ||
1708 | /* Expect step 1 packet from peer */ | |
1709 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, | |
1710 | input_userauth_jpake_server_step1); | |
1711 | ||
1712 | return 1; | |
1713 | } | |
1714 | ||
1715 | void | |
1716 | userauth_jpake_cleanup(Authctxt *authctxt) | |
1717 | { | |
1718 | debug3("%s: clean up", __func__); | |
1719 | if (authctxt->methoddata != NULL) { | |
1720 | jpake_free(authctxt->methoddata); | |
1721 | authctxt->methoddata = NULL; | |
1722 | } | |
1723 | } | |
1724 | #endif /* JPAKE */ | |
1725 | ||
1726 | /* find auth method */ | |
1727 | ||
1728 | /* | |
1729 | * given auth method name, if configurable options permit this method fill | |
1730 | * in auth_ident field and return true, otherwise return false. | |
1731 | */ | |
1732 | static int | |
1733 | authmethod_is_enabled(Authmethod *method) | |
1734 | { | |
1735 | if (method == NULL) | |
1736 | return 0; | |
1737 | /* return false if options indicate this method is disabled */ | |
1738 | if (method->enabled == NULL || *method->enabled == 0) | |
1739 | return 0; | |
1740 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1741 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1742 | return 0; | |
1743 | return 1; | |
1744 | } | |
1745 | ||
1746 | static Authmethod * | |
1747 | authmethod_lookup(const char *name) | |
1748 | { | |
1749 | Authmethod *method = NULL; | |
1750 | if (name != NULL) | |
1751 | for (method = authmethods; method->name != NULL; method++) | |
1752 | if (strcmp(name, method->name) == 0) | |
1753 | return method; | |
1754 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1755 | return NULL; | |
1756 | } | |
1757 | ||
1758 | /* XXX internal state */ | |
1759 | static Authmethod *current = NULL; | |
1760 | static char *supported = NULL; | |
1761 | static char *preferred = NULL; | |
1762 | ||
1763 | /* | |
1764 | * Given the authentication method list sent by the server, return the | |
1765 | * next method we should try. If the server initially sends a nil list, | |
1766 | * use a built-in default list. | |
1767 | */ | |
1768 | static Authmethod * | |
1769 | authmethod_get(char *authlist) | |
1770 | { | |
1771 | char *name = NULL; | |
1772 | u_int next; | |
1773 | ||
1774 | /* Use a suitable default if we're passed a nil list. */ | |
1775 | if (authlist == NULL || strlen(authlist) == 0) | |
1776 | authlist = options.preferred_authentications; | |
1777 | ||
1778 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
1779 | debug3("start over, passed a different list %s", authlist); | |
1780 | if (supported != NULL) | |
1781 | xfree(supported); | |
1782 | supported = xstrdup(authlist); | |
1783 | preferred = options.preferred_authentications; | |
1784 | debug3("preferred %s", preferred); | |
1785 | current = NULL; | |
1786 | } else if (current != NULL && authmethod_is_enabled(current)) | |
1787 | return current; | |
1788 | ||
1789 | for (;;) { | |
1790 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
1791 | debug("No more authentication methods to try."); | |
1792 | current = NULL; | |
1793 | return NULL; | |
1794 | } | |
1795 | preferred += next; | |
1796 | debug3("authmethod_lookup %s", name); | |
1797 | debug3("remaining preferred: %s", preferred); | |
1798 | if ((current = authmethod_lookup(name)) != NULL && | |
1799 | authmethod_is_enabled(current)) { | |
1800 | debug3("authmethod_is_enabled %s", name); | |
1801 | debug("Next authentication method: %s", name); | |
1802 | return current; | |
1803 | } | |
1804 | } | |
1805 | } | |
1806 | ||
1807 | static char * | |
1808 | authmethods_get(void) | |
1809 | { | |
1810 | Authmethod *method = NULL; | |
1811 | Buffer b; | |
1812 | char *list; | |
1813 | ||
1814 | buffer_init(&b); | |
1815 | for (method = authmethods; method->name != NULL; method++) { | |
1816 | if (authmethod_is_enabled(method)) { | |
1817 | if (buffer_len(&b) > 0) | |
1818 | buffer_append(&b, ",", 1); | |
1819 | buffer_append(&b, method->name, strlen(method->name)); | |
1820 | } | |
1821 | } | |
1822 | buffer_append(&b, "\0", 1); | |
1823 | list = xstrdup(buffer_ptr(&b)); | |
1824 | buffer_free(&b); | |
1825 | return list; | |
1826 | } | |
1827 |