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1 | /* $OpenBSD: sshconnect2.c,v 1.164 2007/05/17 23:53:41 jolan Exp $ */ | |
2 | /* | |
3 | * Copyright (c) 2000 Markus Friedl. All rights reserved. | |
4 | * | |
5 | * Redistribution and use in source and binary forms, with or without | |
6 | * modification, are permitted provided that the following conditions | |
7 | * are met: | |
8 | * 1. Redistributions of source code must retain the above copyright | |
9 | * notice, this list of conditions and the following disclaimer. | |
10 | * 2. Redistributions in binary form must reproduce the above copyright | |
11 | * notice, this list of conditions and the following disclaimer in the | |
12 | * documentation and/or other materials provided with the distribution. | |
13 | * | |
14 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
15 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
16 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
17 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
18 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
19 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
20 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
21 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
22 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
23 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
24 | */ | |
25 | ||
26 | #include "includes.h" | |
27 | ||
28 | #include <sys/types.h> | |
29 | #include <sys/socket.h> | |
30 | #include <sys/wait.h> | |
31 | #include <sys/stat.h> | |
32 | ||
33 | #include <errno.h> | |
34 | #include <netdb.h> | |
35 | #include <pwd.h> | |
36 | #include <signal.h> | |
37 | #include <stdarg.h> | |
38 | #include <stdio.h> | |
39 | #include <string.h> | |
40 | #include <unistd.h> | |
41 | ||
42 | #include "openbsd-compat/sys-queue.h" | |
43 | ||
44 | #include "xmalloc.h" | |
45 | #include "ssh.h" | |
46 | #include "ssh2.h" | |
47 | #include "buffer.h" | |
48 | #include "packet.h" | |
49 | #include "compat.h" | |
50 | #include "cipher.h" | |
51 | #include "key.h" | |
52 | #include "kex.h" | |
53 | #include "myproposal.h" | |
54 | #include "sshconnect.h" | |
55 | #include "authfile.h" | |
56 | #include "dh.h" | |
57 | #include "authfd.h" | |
58 | #include "log.h" | |
59 | #include "readconf.h" | |
60 | #include "misc.h" | |
61 | #include "match.h" | |
62 | #include "dispatch.h" | |
63 | #include "canohost.h" | |
64 | #include "msg.h" | |
65 | #include "pathnames.h" | |
66 | #include "uidswap.h" | |
67 | ||
68 | #ifdef GSSAPI | |
69 | #include "ssh-gss.h" | |
70 | #endif | |
71 | ||
72 | /* import */ | |
73 | extern char *client_version_string; | |
74 | extern char *server_version_string; | |
75 | extern Options options; | |
76 | ||
77 | /* | |
78 | * SSH2 key exchange | |
79 | */ | |
80 | ||
81 | u_char *session_id2 = NULL; | |
82 | u_int session_id2_len = 0; | |
83 | ||
84 | char *xxx_host; | |
85 | struct sockaddr *xxx_hostaddr; | |
86 | ||
87 | Kex *xxx_kex = NULL; | |
88 | ||
89 | static int | |
90 | verify_host_key_callback(Key *hostkey) | |
91 | { | |
92 | if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) | |
93 | fatal("Host key verification failed."); | |
94 | return 0; | |
95 | } | |
96 | ||
97 | void | |
98 | ssh_kex2(char *host, struct sockaddr *hostaddr) | |
99 | { | |
100 | Kex *kex; | |
101 | ||
102 | xxx_host = host; | |
103 | xxx_hostaddr = hostaddr; | |
104 | ||
105 | if (options.ciphers == (char *)-1) { | |
106 | logit("No valid ciphers for protocol version 2 given, using defaults."); | |
107 | options.ciphers = NULL; | |
108 | } | |
109 | if (options.ciphers != NULL) { | |
110 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
111 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
112 | } | |
113 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
114 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
115 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
116 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
117 | if (options.compression) { | |
118 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
119 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; | |
120 | } else { | |
121 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
122 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; | |
123 | } | |
124 | if (options.macs != NULL) { | |
125 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
126 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
127 | } | |
128 | if (options.hostkeyalgorithms != NULL) | |
129 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = | |
130 | options.hostkeyalgorithms; | |
131 | ||
132 | if (options.rekey_limit) | |
133 | packet_set_rekey_limit(options.rekey_limit); | |
134 | ||
135 | /* start key exchange */ | |
136 | kex = kex_setup(myproposal); | |
137 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; | |
138 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; | |
139 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; | |
140 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; | |
141 | kex->client_version_string=client_version_string; | |
142 | kex->server_version_string=server_version_string; | |
143 | kex->verify_host_key=&verify_host_key_callback; | |
144 | ||
145 | xxx_kex = kex; | |
146 | ||
147 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
148 | ||
149 | session_id2 = kex->session_id; | |
150 | session_id2_len = kex->session_id_len; | |
151 | ||
152 | #ifdef DEBUG_KEXDH | |
153 | /* send 1st encrypted/maced/compressed message */ | |
154 | packet_start(SSH2_MSG_IGNORE); | |
155 | packet_put_cstring("markus"); | |
156 | packet_send(); | |
157 | packet_write_wait(); | |
158 | #endif | |
159 | } | |
160 | ||
161 | /* | |
162 | * Authenticate user | |
163 | */ | |
164 | ||
165 | typedef struct Authctxt Authctxt; | |
166 | typedef struct Authmethod Authmethod; | |
167 | typedef struct identity Identity; | |
168 | typedef struct idlist Idlist; | |
169 | ||
170 | struct identity { | |
171 | TAILQ_ENTRY(identity) next; | |
172 | AuthenticationConnection *ac; /* set if agent supports key */ | |
173 | Key *key; /* public/private key */ | |
174 | char *filename; /* comment for agent-only keys */ | |
175 | int tried; | |
176 | int isprivate; /* key points to the private key */ | |
177 | }; | |
178 | TAILQ_HEAD(idlist, identity); | |
179 | ||
180 | struct Authctxt { | |
181 | const char *server_user; | |
182 | const char *local_user; | |
183 | const char *host; | |
184 | const char *service; | |
185 | Authmethod *method; | |
186 | int success; | |
187 | char *authlist; | |
188 | /* pubkey */ | |
189 | Idlist keys; | |
190 | AuthenticationConnection *agent; | |
191 | /* hostbased */ | |
192 | Sensitive *sensitive; | |
193 | /* kbd-interactive */ | |
194 | int info_req_seen; | |
195 | /* generic */ | |
196 | void *methoddata; | |
197 | }; | |
198 | struct Authmethod { | |
199 | char *name; /* string to compare against server's list */ | |
200 | int (*userauth)(Authctxt *authctxt); | |
201 | int *enabled; /* flag in option struct that enables method */ | |
202 | int *batch_flag; /* flag in option struct that disables method */ | |
203 | }; | |
204 | ||
205 | void input_userauth_success(int, u_int32_t, void *); | |
206 | void input_userauth_failure(int, u_int32_t, void *); | |
207 | void input_userauth_banner(int, u_int32_t, void *); | |
208 | void input_userauth_error(int, u_int32_t, void *); | |
209 | void input_userauth_info_req(int, u_int32_t, void *); | |
210 | void input_userauth_pk_ok(int, u_int32_t, void *); | |
211 | void input_userauth_passwd_changereq(int, u_int32_t, void *); | |
212 | ||
213 | int userauth_none(Authctxt *); | |
214 | int userauth_pubkey(Authctxt *); | |
215 | int userauth_passwd(Authctxt *); | |
216 | int userauth_kbdint(Authctxt *); | |
217 | int userauth_hostbased(Authctxt *); | |
218 | int userauth_kerberos(Authctxt *); | |
219 | ||
220 | #ifdef GSSAPI | |
221 | int userauth_gssapi(Authctxt *authctxt); | |
222 | void input_gssapi_response(int type, u_int32_t, void *); | |
223 | void input_gssapi_token(int type, u_int32_t, void *); | |
224 | void input_gssapi_hash(int type, u_int32_t, void *); | |
225 | void input_gssapi_error(int, u_int32_t, void *); | |
226 | void input_gssapi_errtok(int, u_int32_t, void *); | |
227 | #endif | |
228 | ||
229 | void userauth(Authctxt *, char *); | |
230 | ||
231 | static int sign_and_send_pubkey(Authctxt *, Identity *); | |
232 | static void pubkey_prepare(Authctxt *); | |
233 | static void pubkey_cleanup(Authctxt *); | |
234 | static Key *load_identity_file(char *); | |
235 | ||
236 | static Authmethod *authmethod_get(char *authlist); | |
237 | static Authmethod *authmethod_lookup(const char *name); | |
238 | static char *authmethods_get(void); | |
239 | ||
240 | Authmethod authmethods[] = { | |
241 | #ifdef GSSAPI | |
242 | {"gssapi-with-mic", | |
243 | userauth_gssapi, | |
244 | &options.gss_authentication, | |
245 | NULL}, | |
246 | #endif | |
247 | {"hostbased", | |
248 | userauth_hostbased, | |
249 | &options.hostbased_authentication, | |
250 | NULL}, | |
251 | {"publickey", | |
252 | userauth_pubkey, | |
253 | &options.pubkey_authentication, | |
254 | NULL}, | |
255 | {"keyboard-interactive", | |
256 | userauth_kbdint, | |
257 | &options.kbd_interactive_authentication, | |
258 | &options.batch_mode}, | |
259 | {"password", | |
260 | userauth_passwd, | |
261 | &options.password_authentication, | |
262 | &options.batch_mode}, | |
263 | {"none", | |
264 | userauth_none, | |
265 | NULL, | |
266 | NULL}, | |
267 | {NULL, NULL, NULL, NULL} | |
268 | }; | |
269 | ||
270 | void | |
271 | ssh_userauth2(const char *local_user, const char *server_user, char *host, | |
272 | Sensitive *sensitive) | |
273 | { | |
274 | Authctxt authctxt; | |
275 | int type; | |
276 | ||
277 | if (options.challenge_response_authentication) | |
278 | options.kbd_interactive_authentication = 1; | |
279 | ||
280 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
281 | packet_put_cstring("ssh-userauth"); | |
282 | packet_send(); | |
283 | debug("SSH2_MSG_SERVICE_REQUEST sent"); | |
284 | packet_write_wait(); | |
285 | type = packet_read(); | |
286 | if (type != SSH2_MSG_SERVICE_ACCEPT) | |
287 | fatal("Server denied authentication request: %d", type); | |
288 | if (packet_remaining() > 0) { | |
289 | char *reply = packet_get_string(NULL); | |
290 | debug2("service_accept: %s", reply); | |
291 | xfree(reply); | |
292 | } else { | |
293 | debug2("buggy server: service_accept w/o service"); | |
294 | } | |
295 | packet_check_eom(); | |
296 | debug("SSH2_MSG_SERVICE_ACCEPT received"); | |
297 | ||
298 | if (options.preferred_authentications == NULL) | |
299 | options.preferred_authentications = authmethods_get(); | |
300 | ||
301 | /* setup authentication context */ | |
302 | memset(&authctxt, 0, sizeof(authctxt)); | |
303 | pubkey_prepare(&authctxt); | |
304 | authctxt.server_user = server_user; | |
305 | authctxt.local_user = local_user; | |
306 | authctxt.host = host; | |
307 | authctxt.service = "ssh-connection"; /* service name */ | |
308 | authctxt.success = 0; | |
309 | authctxt.method = authmethod_lookup("none"); | |
310 | authctxt.authlist = NULL; | |
311 | authctxt.methoddata = NULL; | |
312 | authctxt.sensitive = sensitive; | |
313 | authctxt.info_req_seen = 0; | |
314 | if (authctxt.method == NULL) | |
315 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
316 | ||
317 | /* initial userauth request */ | |
318 | userauth_none(&authctxt); | |
319 | ||
320 | dispatch_init(&input_userauth_error); | |
321 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
322 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
323 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); | |
324 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ | |
325 | ||
326 | pubkey_cleanup(&authctxt); | |
327 | dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); | |
328 | ||
329 | debug("Authentication succeeded (%s).", authctxt.method->name); | |
330 | } | |
331 | ||
332 | void | |
333 | userauth(Authctxt *authctxt, char *authlist) | |
334 | { | |
335 | if (authctxt->methoddata) { | |
336 | xfree(authctxt->methoddata); | |
337 | authctxt->methoddata = NULL; | |
338 | } | |
339 | if (authlist == NULL) { | |
340 | authlist = authctxt->authlist; | |
341 | } else { | |
342 | if (authctxt->authlist) | |
343 | xfree(authctxt->authlist); | |
344 | authctxt->authlist = authlist; | |
345 | } | |
346 | for (;;) { | |
347 | Authmethod *method = authmethod_get(authlist); | |
348 | if (method == NULL) | |
349 | fatal("Permission denied (%s).", authlist); | |
350 | authctxt->method = method; | |
351 | ||
352 | /* reset the per method handler */ | |
353 | dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, | |
354 | SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); | |
355 | ||
356 | /* and try new method */ | |
357 | if (method->userauth(authctxt) != 0) { | |
358 | debug2("we sent a %s packet, wait for reply", method->name); | |
359 | break; | |
360 | } else { | |
361 | debug2("we did not send a packet, disable method"); | |
362 | method->enabled = NULL; | |
363 | } | |
364 | } | |
365 | } | |
366 | ||
367 | void | |
368 | input_userauth_error(int type, u_int32_t seq, void *ctxt) | |
369 | { | |
370 | fatal("input_userauth_error: bad message during authentication: " | |
371 | "type %d", type); | |
372 | } | |
373 | ||
374 | void | |
375 | input_userauth_banner(int type, u_int32_t seq, void *ctxt) | |
376 | { | |
377 | char *msg, *lang; | |
378 | ||
379 | debug3("input_userauth_banner"); | |
380 | msg = packet_get_string(NULL); | |
381 | lang = packet_get_string(NULL); | |
382 | if (options.log_level >= SYSLOG_LEVEL_INFO) | |
383 | fprintf(stderr, "%s", msg); | |
384 | xfree(msg); | |
385 | xfree(lang); | |
386 | } | |
387 | ||
388 | void | |
389 | input_userauth_success(int type, u_int32_t seq, void *ctxt) | |
390 | { | |
391 | Authctxt *authctxt = ctxt; | |
392 | if (authctxt == NULL) | |
393 | fatal("input_userauth_success: no authentication context"); | |
394 | if (authctxt->authlist) { | |
395 | xfree(authctxt->authlist); | |
396 | authctxt->authlist = NULL; | |
397 | } | |
398 | if (authctxt->methoddata) { | |
399 | xfree(authctxt->methoddata); | |
400 | authctxt->methoddata = NULL; | |
401 | } | |
402 | authctxt->success = 1; /* break out */ | |
403 | } | |
404 | ||
405 | void | |
406 | input_userauth_failure(int type, u_int32_t seq, void *ctxt) | |
407 | { | |
408 | Authctxt *authctxt = ctxt; | |
409 | char *authlist = NULL; | |
410 | int partial; | |
411 | ||
412 | if (authctxt == NULL) | |
413 | fatal("input_userauth_failure: no authentication context"); | |
414 | ||
415 | authlist = packet_get_string(NULL); | |
416 | partial = packet_get_char(); | |
417 | packet_check_eom(); | |
418 | ||
419 | if (partial != 0) | |
420 | logit("Authenticated with partial success."); | |
421 | debug("Authentications that can continue: %s", authlist); | |
422 | ||
423 | userauth(authctxt, authlist); | |
424 | } | |
425 | void | |
426 | input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) | |
427 | { | |
428 | Authctxt *authctxt = ctxt; | |
429 | Key *key = NULL; | |
430 | Identity *id = NULL; | |
431 | Buffer b; | |
432 | int pktype, sent = 0; | |
433 | u_int alen, blen; | |
434 | char *pkalg, *fp; | |
435 | u_char *pkblob; | |
436 | ||
437 | if (authctxt == NULL) | |
438 | fatal("input_userauth_pk_ok: no authentication context"); | |
439 | if (datafellows & SSH_BUG_PKOK) { | |
440 | /* this is similar to SSH_BUG_PKAUTH */ | |
441 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
442 | pkblob = packet_get_string(&blen); | |
443 | buffer_init(&b); | |
444 | buffer_append(&b, pkblob, blen); | |
445 | pkalg = buffer_get_string(&b, &alen); | |
446 | buffer_free(&b); | |
447 | } else { | |
448 | pkalg = packet_get_string(&alen); | |
449 | pkblob = packet_get_string(&blen); | |
450 | } | |
451 | packet_check_eom(); | |
452 | ||
453 | debug("Server accepts key: pkalg %s blen %u", pkalg, blen); | |
454 | ||
455 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { | |
456 | debug("unknown pkalg %s", pkalg); | |
457 | goto done; | |
458 | } | |
459 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
460 | debug("no key from blob. pkalg %s", pkalg); | |
461 | goto done; | |
462 | } | |
463 | if (key->type != pktype) { | |
464 | error("input_userauth_pk_ok: type mismatch " | |
465 | "for decoded key (received %d, expected %d)", | |
466 | key->type, pktype); | |
467 | goto done; | |
468 | } | |
469 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); | |
470 | debug2("input_userauth_pk_ok: fp %s", fp); | |
471 | xfree(fp); | |
472 | ||
473 | /* | |
474 | * search keys in the reverse order, because last candidate has been | |
475 | * moved to the end of the queue. this also avoids confusion by | |
476 | * duplicate keys | |
477 | */ | |
478 | TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { | |
479 | if (key_equal(key, id->key)) { | |
480 | sent = sign_and_send_pubkey(authctxt, id); | |
481 | break; | |
482 | } | |
483 | } | |
484 | done: | |
485 | if (key != NULL) | |
486 | key_free(key); | |
487 | xfree(pkalg); | |
488 | xfree(pkblob); | |
489 | ||
490 | /* try another method if we did not send a packet */ | |
491 | if (sent == 0) | |
492 | userauth(authctxt, NULL); | |
493 | } | |
494 | ||
495 | #ifdef GSSAPI | |
496 | int | |
497 | userauth_gssapi(Authctxt *authctxt) | |
498 | { | |
499 | Gssctxt *gssctxt = NULL; | |
500 | static gss_OID_set gss_supported = NULL; | |
501 | static u_int mech = 0; | |
502 | OM_uint32 min; | |
503 | int ok = 0; | |
504 | ||
505 | /* Try one GSSAPI method at a time, rather than sending them all at | |
506 | * once. */ | |
507 | ||
508 | if (gss_supported == NULL) | |
509 | gss_indicate_mechs(&min, &gss_supported); | |
510 | ||
511 | /* Check to see if the mechanism is usable before we offer it */ | |
512 | while (mech < gss_supported->count && !ok) { | |
513 | /* My DER encoding requires length<128 */ | |
514 | if (gss_supported->elements[mech].length < 128 && | |
515 | ssh_gssapi_check_mechanism(&gssctxt, | |
516 | &gss_supported->elements[mech], authctxt->host)) { | |
517 | ok = 1; /* Mechanism works */ | |
518 | } else { | |
519 | mech++; | |
520 | } | |
521 | } | |
522 | ||
523 | if (!ok) | |
524 | return 0; | |
525 | ||
526 | authctxt->methoddata=(void *)gssctxt; | |
527 | ||
528 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
529 | packet_put_cstring(authctxt->server_user); | |
530 | packet_put_cstring(authctxt->service); | |
531 | packet_put_cstring(authctxt->method->name); | |
532 | ||
533 | packet_put_int(1); | |
534 | ||
535 | packet_put_int((gss_supported->elements[mech].length) + 2); | |
536 | packet_put_char(SSH_GSS_OIDTYPE); | |
537 | packet_put_char(gss_supported->elements[mech].length); | |
538 | packet_put_raw(gss_supported->elements[mech].elements, | |
539 | gss_supported->elements[mech].length); | |
540 | ||
541 | packet_send(); | |
542 | ||
543 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); | |
544 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); | |
545 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); | |
546 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); | |
547 | ||
548 | mech++; /* Move along to next candidate */ | |
549 | ||
550 | return 1; | |
551 | } | |
552 | ||
553 | static OM_uint32 | |
554 | process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) | |
555 | { | |
556 | Authctxt *authctxt = ctxt; | |
557 | Gssctxt *gssctxt = authctxt->methoddata; | |
558 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | |
559 | gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; | |
560 | gss_buffer_desc gssbuf; | |
561 | OM_uint32 status, ms, flags; | |
562 | Buffer b; | |
563 | ||
564 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, | |
565 | recv_tok, &send_tok, &flags); | |
566 | ||
567 | if (send_tok.length > 0) { | |
568 | if (GSS_ERROR(status)) | |
569 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); | |
570 | else | |
571 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); | |
572 | ||
573 | packet_put_string(send_tok.value, send_tok.length); | |
574 | packet_send(); | |
575 | gss_release_buffer(&ms, &send_tok); | |
576 | } | |
577 | ||
578 | if (status == GSS_S_COMPLETE) { | |
579 | /* send either complete or MIC, depending on mechanism */ | |
580 | if (!(flags & GSS_C_INTEG_FLAG)) { | |
581 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); | |
582 | packet_send(); | |
583 | } else { | |
584 | ssh_gssapi_buildmic(&b, authctxt->server_user, | |
585 | authctxt->service, "gssapi-with-mic"); | |
586 | ||
587 | gssbuf.value = buffer_ptr(&b); | |
588 | gssbuf.length = buffer_len(&b); | |
589 | ||
590 | status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); | |
591 | ||
592 | if (!GSS_ERROR(status)) { | |
593 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); | |
594 | packet_put_string(mic.value, mic.length); | |
595 | ||
596 | packet_send(); | |
597 | } | |
598 | ||
599 | buffer_free(&b); | |
600 | gss_release_buffer(&ms, &mic); | |
601 | } | |
602 | } | |
603 | ||
604 | return status; | |
605 | } | |
606 | ||
607 | void | |
608 | input_gssapi_response(int type, u_int32_t plen, void *ctxt) | |
609 | { | |
610 | Authctxt *authctxt = ctxt; | |
611 | Gssctxt *gssctxt; | |
612 | int oidlen; | |
613 | char *oidv; | |
614 | ||
615 | if (authctxt == NULL) | |
616 | fatal("input_gssapi_response: no authentication context"); | |
617 | gssctxt = authctxt->methoddata; | |
618 | ||
619 | /* Setup our OID */ | |
620 | oidv = packet_get_string(&oidlen); | |
621 | ||
622 | if (oidlen <= 2 || | |
623 | oidv[0] != SSH_GSS_OIDTYPE || | |
624 | oidv[1] != oidlen - 2) { | |
625 | xfree(oidv); | |
626 | debug("Badly encoded mechanism OID received"); | |
627 | userauth(authctxt, NULL); | |
628 | return; | |
629 | } | |
630 | ||
631 | if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) | |
632 | fatal("Server returned different OID than expected"); | |
633 | ||
634 | packet_check_eom(); | |
635 | ||
636 | xfree(oidv); | |
637 | ||
638 | if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { | |
639 | /* Start again with next method on list */ | |
640 | debug("Trying to start again"); | |
641 | userauth(authctxt, NULL); | |
642 | return; | |
643 | } | |
644 | } | |
645 | ||
646 | void | |
647 | input_gssapi_token(int type, u_int32_t plen, void *ctxt) | |
648 | { | |
649 | Authctxt *authctxt = ctxt; | |
650 | gss_buffer_desc recv_tok; | |
651 | OM_uint32 status; | |
652 | u_int slen; | |
653 | ||
654 | if (authctxt == NULL) | |
655 | fatal("input_gssapi_response: no authentication context"); | |
656 | ||
657 | recv_tok.value = packet_get_string(&slen); | |
658 | recv_tok.length = slen; /* safe typecast */ | |
659 | ||
660 | packet_check_eom(); | |
661 | ||
662 | status = process_gssapi_token(ctxt, &recv_tok); | |
663 | ||
664 | xfree(recv_tok.value); | |
665 | ||
666 | if (GSS_ERROR(status)) { | |
667 | /* Start again with the next method in the list */ | |
668 | userauth(authctxt, NULL); | |
669 | return; | |
670 | } | |
671 | } | |
672 | ||
673 | void | |
674 | input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) | |
675 | { | |
676 | Authctxt *authctxt = ctxt; | |
677 | Gssctxt *gssctxt; | |
678 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | |
679 | gss_buffer_desc recv_tok; | |
680 | OM_uint32 status, ms; | |
681 | u_int len; | |
682 | ||
683 | if (authctxt == NULL) | |
684 | fatal("input_gssapi_response: no authentication context"); | |
685 | gssctxt = authctxt->methoddata; | |
686 | ||
687 | recv_tok.value = packet_get_string(&len); | |
688 | recv_tok.length = len; | |
689 | ||
690 | packet_check_eom(); | |
691 | ||
692 | /* Stick it into GSSAPI and see what it says */ | |
693 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, | |
694 | &recv_tok, &send_tok, NULL); | |
695 | ||
696 | xfree(recv_tok.value); | |
697 | gss_release_buffer(&ms, &send_tok); | |
698 | ||
699 | /* Server will be returning a failed packet after this one */ | |
700 | } | |
701 | ||
702 | void | |
703 | input_gssapi_error(int type, u_int32_t plen, void *ctxt) | |
704 | { | |
705 | OM_uint32 maj, min; | |
706 | char *msg; | |
707 | char *lang; | |
708 | ||
709 | maj=packet_get_int(); | |
710 | min=packet_get_int(); | |
711 | msg=packet_get_string(NULL); | |
712 | lang=packet_get_string(NULL); | |
713 | ||
714 | packet_check_eom(); | |
715 | ||
716 | debug("Server GSSAPI Error:\n%s", msg); | |
717 | xfree(msg); | |
718 | xfree(lang); | |
719 | } | |
720 | #endif /* GSSAPI */ | |
721 | ||
722 | int | |
723 | userauth_none(Authctxt *authctxt) | |
724 | { | |
725 | /* initial userauth request */ | |
726 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
727 | packet_put_cstring(authctxt->server_user); | |
728 | packet_put_cstring(authctxt->service); | |
729 | packet_put_cstring(authctxt->method->name); | |
730 | packet_send(); | |
731 | return 1; | |
732 | } | |
733 | ||
734 | int | |
735 | userauth_passwd(Authctxt *authctxt) | |
736 | { | |
737 | static int attempt = 0; | |
738 | char prompt[150]; | |
739 | char *password; | |
740 | ||
741 | if (attempt++ >= options.number_of_password_prompts) | |
742 | return 0; | |
743 | ||
744 | if (attempt != 1) | |
745 | error("Permission denied, please try again."); | |
746 | ||
747 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", | |
748 | authctxt->server_user, authctxt->host); | |
749 | password = read_passphrase(prompt, 0); | |
750 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
751 | packet_put_cstring(authctxt->server_user); | |
752 | packet_put_cstring(authctxt->service); | |
753 | packet_put_cstring(authctxt->method->name); | |
754 | packet_put_char(0); | |
755 | packet_put_cstring(password); | |
756 | memset(password, 0, strlen(password)); | |
757 | xfree(password); | |
758 | packet_add_padding(64); | |
759 | packet_send(); | |
760 | ||
761 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, | |
762 | &input_userauth_passwd_changereq); | |
763 | ||
764 | return 1; | |
765 | } | |
766 | /* | |
767 | * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST | |
768 | */ | |
769 | void | |
770 | input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) | |
771 | { | |
772 | Authctxt *authctxt = ctxt; | |
773 | char *info, *lang, *password = NULL, *retype = NULL; | |
774 | char prompt[150]; | |
775 | ||
776 | debug2("input_userauth_passwd_changereq"); | |
777 | ||
778 | if (authctxt == NULL) | |
779 | fatal("input_userauth_passwd_changereq: " | |
780 | "no authentication context"); | |
781 | ||
782 | info = packet_get_string(NULL); | |
783 | lang = packet_get_string(NULL); | |
784 | if (strlen(info) > 0) | |
785 | logit("%s", info); | |
786 | xfree(info); | |
787 | xfree(lang); | |
788 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
789 | packet_put_cstring(authctxt->server_user); | |
790 | packet_put_cstring(authctxt->service); | |
791 | packet_put_cstring(authctxt->method->name); | |
792 | packet_put_char(1); /* additional info */ | |
793 | snprintf(prompt, sizeof(prompt), | |
794 | "Enter %.30s@%.128s's old password: ", | |
795 | authctxt->server_user, authctxt->host); | |
796 | password = read_passphrase(prompt, 0); | |
797 | packet_put_cstring(password); | |
798 | memset(password, 0, strlen(password)); | |
799 | xfree(password); | |
800 | password = NULL; | |
801 | while (password == NULL) { | |
802 | snprintf(prompt, sizeof(prompt), | |
803 | "Enter %.30s@%.128s's new password: ", | |
804 | authctxt->server_user, authctxt->host); | |
805 | password = read_passphrase(prompt, RP_ALLOW_EOF); | |
806 | if (password == NULL) { | |
807 | /* bail out */ | |
808 | return; | |
809 | } | |
810 | snprintf(prompt, sizeof(prompt), | |
811 | "Retype %.30s@%.128s's new password: ", | |
812 | authctxt->server_user, authctxt->host); | |
813 | retype = read_passphrase(prompt, 0); | |
814 | if (strcmp(password, retype) != 0) { | |
815 | memset(password, 0, strlen(password)); | |
816 | xfree(password); | |
817 | logit("Mismatch; try again, EOF to quit."); | |
818 | password = NULL; | |
819 | } | |
820 | memset(retype, 0, strlen(retype)); | |
821 | xfree(retype); | |
822 | } | |
823 | packet_put_cstring(password); | |
824 | memset(password, 0, strlen(password)); | |
825 | xfree(password); | |
826 | packet_add_padding(64); | |
827 | packet_send(); | |
828 | ||
829 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, | |
830 | &input_userauth_passwd_changereq); | |
831 | } | |
832 | ||
833 | static int | |
834 | identity_sign(Identity *id, u_char **sigp, u_int *lenp, | |
835 | u_char *data, u_int datalen) | |
836 | { | |
837 | Key *prv; | |
838 | int ret; | |
839 | ||
840 | /* the agent supports this key */ | |
841 | if (id->ac) | |
842 | return (ssh_agent_sign(id->ac, id->key, sigp, lenp, | |
843 | data, datalen)); | |
844 | /* | |
845 | * we have already loaded the private key or | |
846 | * the private key is stored in external hardware | |
847 | */ | |
848 | if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) | |
849 | return (key_sign(id->key, sigp, lenp, data, datalen)); | |
850 | /* load the private key from the file */ | |
851 | if ((prv = load_identity_file(id->filename)) == NULL) | |
852 | return (-1); | |
853 | ret = key_sign(prv, sigp, lenp, data, datalen); | |
854 | key_free(prv); | |
855 | return (ret); | |
856 | } | |
857 | ||
858 | static int | |
859 | sign_and_send_pubkey(Authctxt *authctxt, Identity *id) | |
860 | { | |
861 | Buffer b; | |
862 | u_char *blob, *signature; | |
863 | u_int bloblen, slen; | |
864 | u_int skip = 0; | |
865 | int ret = -1; | |
866 | int have_sig = 1; | |
867 | ||
868 | debug3("sign_and_send_pubkey"); | |
869 | ||
870 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { | |
871 | /* we cannot handle this key */ | |
872 | debug3("sign_and_send_pubkey: cannot handle key"); | |
873 | return 0; | |
874 | } | |
875 | /* data to be signed */ | |
876 | buffer_init(&b); | |
877 | if (datafellows & SSH_OLD_SESSIONID) { | |
878 | buffer_append(&b, session_id2, session_id2_len); | |
879 | skip = session_id2_len; | |
880 | } else { | |
881 | buffer_put_string(&b, session_id2, session_id2_len); | |
882 | skip = buffer_len(&b); | |
883 | } | |
884 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
885 | buffer_put_cstring(&b, authctxt->server_user); | |
886 | buffer_put_cstring(&b, | |
887 | datafellows & SSH_BUG_PKSERVICE ? | |
888 | "ssh-userauth" : | |
889 | authctxt->service); | |
890 | if (datafellows & SSH_BUG_PKAUTH) { | |
891 | buffer_put_char(&b, have_sig); | |
892 | } else { | |
893 | buffer_put_cstring(&b, authctxt->method->name); | |
894 | buffer_put_char(&b, have_sig); | |
895 | buffer_put_cstring(&b, key_ssh_name(id->key)); | |
896 | } | |
897 | buffer_put_string(&b, blob, bloblen); | |
898 | ||
899 | /* generate signature */ | |
900 | ret = identity_sign(id, &signature, &slen, | |
901 | buffer_ptr(&b), buffer_len(&b)); | |
902 | if (ret == -1) { | |
903 | xfree(blob); | |
904 | buffer_free(&b); | |
905 | return 0; | |
906 | } | |
907 | #ifdef DEBUG_PK | |
908 | buffer_dump(&b); | |
909 | #endif | |
910 | if (datafellows & SSH_BUG_PKSERVICE) { | |
911 | buffer_clear(&b); | |
912 | buffer_append(&b, session_id2, session_id2_len); | |
913 | skip = session_id2_len; | |
914 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
915 | buffer_put_cstring(&b, authctxt->server_user); | |
916 | buffer_put_cstring(&b, authctxt->service); | |
917 | buffer_put_cstring(&b, authctxt->method->name); | |
918 | buffer_put_char(&b, have_sig); | |
919 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
920 | buffer_put_cstring(&b, key_ssh_name(id->key)); | |
921 | buffer_put_string(&b, blob, bloblen); | |
922 | } | |
923 | xfree(blob); | |
924 | ||
925 | /* append signature */ | |
926 | buffer_put_string(&b, signature, slen); | |
927 | xfree(signature); | |
928 | ||
929 | /* skip session id and packet type */ | |
930 | if (buffer_len(&b) < skip + 1) | |
931 | fatal("userauth_pubkey: internal error"); | |
932 | buffer_consume(&b, skip + 1); | |
933 | ||
934 | /* put remaining data from buffer into packet */ | |
935 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
936 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
937 | buffer_free(&b); | |
938 | packet_send(); | |
939 | ||
940 | return 1; | |
941 | } | |
942 | ||
943 | static int | |
944 | send_pubkey_test(Authctxt *authctxt, Identity *id) | |
945 | { | |
946 | u_char *blob; | |
947 | u_int bloblen, have_sig = 0; | |
948 | ||
949 | debug3("send_pubkey_test"); | |
950 | ||
951 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { | |
952 | /* we cannot handle this key */ | |
953 | debug3("send_pubkey_test: cannot handle key"); | |
954 | return 0; | |
955 | } | |
956 | /* register callback for USERAUTH_PK_OK message */ | |
957 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
958 | ||
959 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
960 | packet_put_cstring(authctxt->server_user); | |
961 | packet_put_cstring(authctxt->service); | |
962 | packet_put_cstring(authctxt->method->name); | |
963 | packet_put_char(have_sig); | |
964 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
965 | packet_put_cstring(key_ssh_name(id->key)); | |
966 | packet_put_string(blob, bloblen); | |
967 | xfree(blob); | |
968 | packet_send(); | |
969 | return 1; | |
970 | } | |
971 | ||
972 | static Key * | |
973 | load_identity_file(char *filename) | |
974 | { | |
975 | Key *private; | |
976 | char prompt[300], *passphrase; | |
977 | int perm_ok, quit, i; | |
978 | struct stat st; | |
979 | ||
980 | if (stat(filename, &st) < 0) { | |
981 | debug3("no such identity: %s", filename); | |
982 | return NULL; | |
983 | } | |
984 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); | |
985 | if (!perm_ok) | |
986 | return NULL; | |
987 | if (private == NULL) { | |
988 | if (options.batch_mode) | |
989 | return NULL; | |
990 | snprintf(prompt, sizeof prompt, | |
991 | "Enter passphrase for key '%.100s': ", filename); | |
992 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
993 | passphrase = read_passphrase(prompt, 0); | |
994 | if (strcmp(passphrase, "") != 0) { | |
995 | private = key_load_private_type(KEY_UNSPEC, | |
996 | filename, passphrase, NULL, NULL); | |
997 | quit = 0; | |
998 | } else { | |
999 | debug2("no passphrase given, try next key"); | |
1000 | quit = 1; | |
1001 | } | |
1002 | memset(passphrase, 0, strlen(passphrase)); | |
1003 | xfree(passphrase); | |
1004 | if (private != NULL || quit) | |
1005 | break; | |
1006 | debug2("bad passphrase given, try again..."); | |
1007 | } | |
1008 | } | |
1009 | return private; | |
1010 | } | |
1011 | ||
1012 | /* | |
1013 | * try keys in the following order: | |
1014 | * 1. agent keys that are found in the config file | |
1015 | * 2. other agent keys | |
1016 | * 3. keys that are only listed in the config file | |
1017 | */ | |
1018 | static void | |
1019 | pubkey_prepare(Authctxt *authctxt) | |
1020 | { | |
1021 | Identity *id; | |
1022 | Idlist agent, files, *preferred; | |
1023 | Key *key; | |
1024 | AuthenticationConnection *ac; | |
1025 | char *comment; | |
1026 | int i, found; | |
1027 | ||
1028 | TAILQ_INIT(&agent); /* keys from the agent */ | |
1029 | TAILQ_INIT(&files); /* keys from the config file */ | |
1030 | preferred = &authctxt->keys; | |
1031 | TAILQ_INIT(preferred); /* preferred order of keys */ | |
1032 | ||
1033 | /* list of keys stored in the filesystem */ | |
1034 | for (i = 0; i < options.num_identity_files; i++) { | |
1035 | key = options.identity_keys[i]; | |
1036 | if (key && key->type == KEY_RSA1) | |
1037 | continue; | |
1038 | options.identity_keys[i] = NULL; | |
1039 | id = xcalloc(1, sizeof(*id)); | |
1040 | id->key = key; | |
1041 | id->filename = xstrdup(options.identity_files[i]); | |
1042 | TAILQ_INSERT_TAIL(&files, id, next); | |
1043 | } | |
1044 | /* list of keys supported by the agent */ | |
1045 | if ((ac = ssh_get_authentication_connection())) { | |
1046 | for (key = ssh_get_first_identity(ac, &comment, 2); | |
1047 | key != NULL; | |
1048 | key = ssh_get_next_identity(ac, &comment, 2)) { | |
1049 | found = 0; | |
1050 | TAILQ_FOREACH(id, &files, next) { | |
1051 | /* agent keys from the config file are preferred */ | |
1052 | if (key_equal(key, id->key)) { | |
1053 | key_free(key); | |
1054 | xfree(comment); | |
1055 | TAILQ_REMOVE(&files, id, next); | |
1056 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1057 | id->ac = ac; | |
1058 | found = 1; | |
1059 | break; | |
1060 | } | |
1061 | } | |
1062 | if (!found && !options.identities_only) { | |
1063 | id = xcalloc(1, sizeof(*id)); | |
1064 | id->key = key; | |
1065 | id->filename = comment; | |
1066 | id->ac = ac; | |
1067 | TAILQ_INSERT_TAIL(&agent, id, next); | |
1068 | } | |
1069 | } | |
1070 | /* append remaining agent keys */ | |
1071 | for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { | |
1072 | TAILQ_REMOVE(&agent, id, next); | |
1073 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1074 | } | |
1075 | authctxt->agent = ac; | |
1076 | } | |
1077 | /* append remaining keys from the config file */ | |
1078 | for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { | |
1079 | TAILQ_REMOVE(&files, id, next); | |
1080 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1081 | } | |
1082 | TAILQ_FOREACH(id, preferred, next) { | |
1083 | debug2("key: %s (%p)", id->filename, id->key); | |
1084 | } | |
1085 | } | |
1086 | ||
1087 | static void | |
1088 | pubkey_cleanup(Authctxt *authctxt) | |
1089 | { | |
1090 | Identity *id; | |
1091 | ||
1092 | if (authctxt->agent != NULL) | |
1093 | ssh_close_authentication_connection(authctxt->agent); | |
1094 | for (id = TAILQ_FIRST(&authctxt->keys); id; | |
1095 | id = TAILQ_FIRST(&authctxt->keys)) { | |
1096 | TAILQ_REMOVE(&authctxt->keys, id, next); | |
1097 | if (id->key) | |
1098 | key_free(id->key); | |
1099 | if (id->filename) | |
1100 | xfree(id->filename); | |
1101 | xfree(id); | |
1102 | } | |
1103 | } | |
1104 | ||
1105 | int | |
1106 | userauth_pubkey(Authctxt *authctxt) | |
1107 | { | |
1108 | Identity *id; | |
1109 | int sent = 0; | |
1110 | ||
1111 | while ((id = TAILQ_FIRST(&authctxt->keys))) { | |
1112 | if (id->tried++) | |
1113 | return (0); | |
1114 | /* move key to the end of the queue */ | |
1115 | TAILQ_REMOVE(&authctxt->keys, id, next); | |
1116 | TAILQ_INSERT_TAIL(&authctxt->keys, id, next); | |
1117 | /* | |
1118 | * send a test message if we have the public key. for | |
1119 | * encrypted keys we cannot do this and have to load the | |
1120 | * private key instead | |
1121 | */ | |
1122 | if (id->key && id->key->type != KEY_RSA1) { | |
1123 | debug("Offering public key: %s", id->filename); | |
1124 | sent = send_pubkey_test(authctxt, id); | |
1125 | } else if (id->key == NULL) { | |
1126 | debug("Trying private key: %s", id->filename); | |
1127 | id->key = load_identity_file(id->filename); | |
1128 | if (id->key != NULL) { | |
1129 | id->isprivate = 1; | |
1130 | sent = sign_and_send_pubkey(authctxt, id); | |
1131 | key_free(id->key); | |
1132 | id->key = NULL; | |
1133 | } | |
1134 | } | |
1135 | if (sent) | |
1136 | return (sent); | |
1137 | } | |
1138 | return (0); | |
1139 | } | |
1140 | ||
1141 | /* | |
1142 | * Send userauth request message specifying keyboard-interactive method. | |
1143 | */ | |
1144 | int | |
1145 | userauth_kbdint(Authctxt *authctxt) | |
1146 | { | |
1147 | static int attempt = 0; | |
1148 | ||
1149 | if (attempt++ >= options.number_of_password_prompts) | |
1150 | return 0; | |
1151 | /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ | |
1152 | if (attempt > 1 && !authctxt->info_req_seen) { | |
1153 | debug3("userauth_kbdint: disable: no info_req_seen"); | |
1154 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); | |
1155 | return 0; | |
1156 | } | |
1157 | ||
1158 | debug2("userauth_kbdint"); | |
1159 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1160 | packet_put_cstring(authctxt->server_user); | |
1161 | packet_put_cstring(authctxt->service); | |
1162 | packet_put_cstring(authctxt->method->name); | |
1163 | packet_put_cstring(""); /* lang */ | |
1164 | packet_put_cstring(options.kbd_interactive_devices ? | |
1165 | options.kbd_interactive_devices : ""); | |
1166 | packet_send(); | |
1167 | ||
1168 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1169 | return 1; | |
1170 | } | |
1171 | ||
1172 | /* | |
1173 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE | |
1174 | */ | |
1175 | void | |
1176 | input_userauth_info_req(int type, u_int32_t seq, void *ctxt) | |
1177 | { | |
1178 | Authctxt *authctxt = ctxt; | |
1179 | char *name, *inst, *lang, *prompt, *response; | |
1180 | u_int num_prompts, i; | |
1181 | int echo = 0; | |
1182 | ||
1183 | debug2("input_userauth_info_req"); | |
1184 | ||
1185 | if (authctxt == NULL) | |
1186 | fatal("input_userauth_info_req: no authentication context"); | |
1187 | ||
1188 | authctxt->info_req_seen = 1; | |
1189 | ||
1190 | name = packet_get_string(NULL); | |
1191 | inst = packet_get_string(NULL); | |
1192 | lang = packet_get_string(NULL); | |
1193 | if (strlen(name) > 0) | |
1194 | logit("%s", name); | |
1195 | if (strlen(inst) > 0) | |
1196 | logit("%s", inst); | |
1197 | xfree(name); | |
1198 | xfree(inst); | |
1199 | xfree(lang); | |
1200 | ||
1201 | num_prompts = packet_get_int(); | |
1202 | /* | |
1203 | * Begin to build info response packet based on prompts requested. | |
1204 | * We commit to providing the correct number of responses, so if | |
1205 | * further on we run into a problem that prevents this, we have to | |
1206 | * be sure and clean this up and send a correct error response. | |
1207 | */ | |
1208 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1209 | packet_put_int(num_prompts); | |
1210 | ||
1211 | debug2("input_userauth_info_req: num_prompts %d", num_prompts); | |
1212 | for (i = 0; i < num_prompts; i++) { | |
1213 | prompt = packet_get_string(NULL); | |
1214 | echo = packet_get_char(); | |
1215 | ||
1216 | response = read_passphrase(prompt, echo ? RP_ECHO : 0); | |
1217 | ||
1218 | packet_put_cstring(response); | |
1219 | memset(response, 0, strlen(response)); | |
1220 | xfree(response); | |
1221 | xfree(prompt); | |
1222 | } | |
1223 | packet_check_eom(); /* done with parsing incoming message. */ | |
1224 | ||
1225 | packet_add_padding(64); | |
1226 | packet_send(); | |
1227 | } | |
1228 | ||
1229 | static int | |
1230 | ssh_keysign(Key *key, u_char **sigp, u_int *lenp, | |
1231 | u_char *data, u_int datalen) | |
1232 | { | |
1233 | Buffer b; | |
1234 | struct stat st; | |
1235 | pid_t pid; | |
1236 | int to[2], from[2], status, version = 2; | |
1237 | ||
1238 | debug2("ssh_keysign called"); | |
1239 | ||
1240 | if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { | |
1241 | error("ssh_keysign: no installed: %s", strerror(errno)); | |
1242 | return -1; | |
1243 | } | |
1244 | if (fflush(stdout) != 0) | |
1245 | error("ssh_keysign: fflush: %s", strerror(errno)); | |
1246 | if (pipe(to) < 0) { | |
1247 | error("ssh_keysign: pipe: %s", strerror(errno)); | |
1248 | return -1; | |
1249 | } | |
1250 | if (pipe(from) < 0) { | |
1251 | error("ssh_keysign: pipe: %s", strerror(errno)); | |
1252 | return -1; | |
1253 | } | |
1254 | if ((pid = fork()) < 0) { | |
1255 | error("ssh_keysign: fork: %s", strerror(errno)); | |
1256 | return -1; | |
1257 | } | |
1258 | if (pid == 0) { | |
1259 | permanently_drop_suid(getuid()); | |
1260 | close(from[0]); | |
1261 | if (dup2(from[1], STDOUT_FILENO) < 0) | |
1262 | fatal("ssh_keysign: dup2: %s", strerror(errno)); | |
1263 | close(to[1]); | |
1264 | if (dup2(to[0], STDIN_FILENO) < 0) | |
1265 | fatal("ssh_keysign: dup2: %s", strerror(errno)); | |
1266 | close(from[1]); | |
1267 | close(to[0]); | |
1268 | execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); | |
1269 | fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, | |
1270 | strerror(errno)); | |
1271 | } | |
1272 | close(from[1]); | |
1273 | close(to[0]); | |
1274 | ||
1275 | buffer_init(&b); | |
1276 | buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ | |
1277 | buffer_put_string(&b, data, datalen); | |
1278 | if (ssh_msg_send(to[1], version, &b) == -1) | |
1279 | fatal("ssh_keysign: couldn't send request"); | |
1280 | ||
1281 | if (ssh_msg_recv(from[0], &b) < 0) { | |
1282 | error("ssh_keysign: no reply"); | |
1283 | buffer_free(&b); | |
1284 | return -1; | |
1285 | } | |
1286 | close(from[0]); | |
1287 | close(to[1]); | |
1288 | ||
1289 | while (waitpid(pid, &status, 0) < 0) | |
1290 | if (errno != EINTR) | |
1291 | break; | |
1292 | ||
1293 | if (buffer_get_char(&b) != version) { | |
1294 | error("ssh_keysign: bad version"); | |
1295 | buffer_free(&b); | |
1296 | return -1; | |
1297 | } | |
1298 | *sigp = buffer_get_string(&b, lenp); | |
1299 | buffer_free(&b); | |
1300 | ||
1301 | return 0; | |
1302 | } | |
1303 | ||
1304 | int | |
1305 | userauth_hostbased(Authctxt *authctxt) | |
1306 | { | |
1307 | Key *private = NULL; | |
1308 | Sensitive *sensitive = authctxt->sensitive; | |
1309 | Buffer b; | |
1310 | u_char *signature, *blob; | |
1311 | char *chost, *pkalg, *p, myname[NI_MAXHOST]; | |
1312 | const char *service; | |
1313 | u_int blen, slen; | |
1314 | int ok, i, len, found = 0; | |
1315 | ||
1316 | /* check for a useful key */ | |
1317 | for (i = 0; i < sensitive->nkeys; i++) { | |
1318 | private = sensitive->keys[i]; | |
1319 | if (private && private->type != KEY_RSA1) { | |
1320 | found = 1; | |
1321 | /* we take and free the key */ | |
1322 | sensitive->keys[i] = NULL; | |
1323 | break; | |
1324 | } | |
1325 | } | |
1326 | if (!found) { | |
1327 | debug("No more client hostkeys for hostbased authentication."); | |
1328 | return 0; | |
1329 | } | |
1330 | if (key_to_blob(private, &blob, &blen) == 0) { | |
1331 | key_free(private); | |
1332 | return 0; | |
1333 | } | |
1334 | /* figure out a name for the client host */ | |
1335 | p = NULL; | |
1336 | if (packet_connection_is_on_socket()) | |
1337 | p = get_local_name(packet_get_connection_in()); | |
1338 | if (p == NULL) { | |
1339 | if (gethostname(myname, sizeof(myname)) == -1) { | |
1340 | verbose("userauth_hostbased: gethostname: %s", | |
1341 | strerror(errno)); | |
1342 | } else | |
1343 | p = xstrdup(myname); | |
1344 | } | |
1345 | if (p == NULL) { | |
1346 | error("userauth_hostbased: cannot get local ipaddr/name"); | |
1347 | key_free(private); | |
1348 | xfree(blob); | |
1349 | return 0; | |
1350 | } | |
1351 | len = strlen(p) + 2; | |
1352 | xasprintf(&chost, "%s.", p); | |
1353 | debug2("userauth_hostbased: chost %s", chost); | |
1354 | xfree(p); | |
1355 | ||
1356 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : | |
1357 | authctxt->service; | |
1358 | pkalg = xstrdup(key_ssh_name(private)); | |
1359 | buffer_init(&b); | |
1360 | /* construct data */ | |
1361 | buffer_put_string(&b, session_id2, session_id2_len); | |
1362 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
1363 | buffer_put_cstring(&b, authctxt->server_user); | |
1364 | buffer_put_cstring(&b, service); | |
1365 | buffer_put_cstring(&b, authctxt->method->name); | |
1366 | buffer_put_cstring(&b, pkalg); | |
1367 | buffer_put_string(&b, blob, blen); | |
1368 | buffer_put_cstring(&b, chost); | |
1369 | buffer_put_cstring(&b, authctxt->local_user); | |
1370 | #ifdef DEBUG_PK | |
1371 | buffer_dump(&b); | |
1372 | #endif | |
1373 | if (sensitive->external_keysign) | |
1374 | ok = ssh_keysign(private, &signature, &slen, | |
1375 | buffer_ptr(&b), buffer_len(&b)); | |
1376 | else | |
1377 | ok = key_sign(private, &signature, &slen, | |
1378 | buffer_ptr(&b), buffer_len(&b)); | |
1379 | key_free(private); | |
1380 | buffer_free(&b); | |
1381 | if (ok != 0) { | |
1382 | error("key_sign failed"); | |
1383 | xfree(chost); | |
1384 | xfree(pkalg); | |
1385 | xfree(blob); | |
1386 | return 0; | |
1387 | } | |
1388 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1389 | packet_put_cstring(authctxt->server_user); | |
1390 | packet_put_cstring(authctxt->service); | |
1391 | packet_put_cstring(authctxt->method->name); | |
1392 | packet_put_cstring(pkalg); | |
1393 | packet_put_string(blob, blen); | |
1394 | packet_put_cstring(chost); | |
1395 | packet_put_cstring(authctxt->local_user); | |
1396 | packet_put_string(signature, slen); | |
1397 | memset(signature, 's', slen); | |
1398 | xfree(signature); | |
1399 | xfree(chost); | |
1400 | xfree(pkalg); | |
1401 | xfree(blob); | |
1402 | ||
1403 | packet_send(); | |
1404 | return 1; | |
1405 | } | |
1406 | ||
1407 | /* find auth method */ | |
1408 | ||
1409 | /* | |
1410 | * given auth method name, if configurable options permit this method fill | |
1411 | * in auth_ident field and return true, otherwise return false. | |
1412 | */ | |
1413 | static int | |
1414 | authmethod_is_enabled(Authmethod *method) | |
1415 | { | |
1416 | if (method == NULL) | |
1417 | return 0; | |
1418 | /* return false if options indicate this method is disabled */ | |
1419 | if (method->enabled == NULL || *method->enabled == 0) | |
1420 | return 0; | |
1421 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1422 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1423 | return 0; | |
1424 | return 1; | |
1425 | } | |
1426 | ||
1427 | static Authmethod * | |
1428 | authmethod_lookup(const char *name) | |
1429 | { | |
1430 | Authmethod *method = NULL; | |
1431 | if (name != NULL) | |
1432 | for (method = authmethods; method->name != NULL; method++) | |
1433 | if (strcmp(name, method->name) == 0) | |
1434 | return method; | |
1435 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1436 | return NULL; | |
1437 | } | |
1438 | ||
1439 | /* XXX internal state */ | |
1440 | static Authmethod *current = NULL; | |
1441 | static char *supported = NULL; | |
1442 | static char *preferred = NULL; | |
1443 | ||
1444 | /* | |
1445 | * Given the authentication method list sent by the server, return the | |
1446 | * next method we should try. If the server initially sends a nil list, | |
1447 | * use a built-in default list. | |
1448 | */ | |
1449 | static Authmethod * | |
1450 | authmethod_get(char *authlist) | |
1451 | { | |
1452 | char *name = NULL; | |
1453 | u_int next; | |
1454 | ||
1455 | /* Use a suitable default if we're passed a nil list. */ | |
1456 | if (authlist == NULL || strlen(authlist) == 0) | |
1457 | authlist = options.preferred_authentications; | |
1458 | ||
1459 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
1460 | debug3("start over, passed a different list %s", authlist); | |
1461 | if (supported != NULL) | |
1462 | xfree(supported); | |
1463 | supported = xstrdup(authlist); | |
1464 | preferred = options.preferred_authentications; | |
1465 | debug3("preferred %s", preferred); | |
1466 | current = NULL; | |
1467 | } else if (current != NULL && authmethod_is_enabled(current)) | |
1468 | return current; | |
1469 | ||
1470 | for (;;) { | |
1471 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
1472 | debug("No more authentication methods to try."); | |
1473 | current = NULL; | |
1474 | return NULL; | |
1475 | } | |
1476 | preferred += next; | |
1477 | debug3("authmethod_lookup %s", name); | |
1478 | debug3("remaining preferred: %s", preferred); | |
1479 | if ((current = authmethod_lookup(name)) != NULL && | |
1480 | authmethod_is_enabled(current)) { | |
1481 | debug3("authmethod_is_enabled %s", name); | |
1482 | debug("Next authentication method: %s", name); | |
1483 | return current; | |
1484 | } | |
1485 | } | |
1486 | } | |
1487 | ||
1488 | static char * | |
1489 | authmethods_get(void) | |
1490 | { | |
1491 | Authmethod *method = NULL; | |
1492 | Buffer b; | |
1493 | char *list; | |
1494 | ||
1495 | buffer_init(&b); | |
1496 | for (method = authmethods; method->name != NULL; method++) { | |
1497 | if (authmethod_is_enabled(method)) { | |
1498 | if (buffer_len(&b) > 0) | |
1499 | buffer_append(&b, ",", 1); | |
1500 | buffer_append(&b, method->name, strlen(method->name)); | |
1501 | } | |
1502 | } | |
1503 | buffer_append(&b, "\0", 1); | |
1504 | list = xstrdup(buffer_ptr(&b)); | |
1505 | buffer_free(&b); | |
1506 | return list; | |
1507 | } |