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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 | extern Kex *xxx_kex; | |
82 | ||
83 | /* tty_flag is set in ssh.c. use this in ssh_userauth2 */ | |
84 | /* if it is set then prevent the switch to the null cipher */ | |
85 | ||
86 | extern int tty_flag; | |
87 | ||
88 | /* tty_flag is set in ssh.c. use this in ssh_userauth2 */ | |
89 | /* if it is set then prevent the switch to the null cipher */ | |
90 | ||
91 | extern int tty_flag; | |
92 | ||
93 | /* tty_flag is set in ssh.c. use this in ssh_userauth2 */ | |
94 | /* if it is set then prevent the switch to the null cipher */ | |
95 | ||
96 | extern int tty_flag; | |
97 | ||
98 | /* | |
99 | * SSH2 key exchange | |
100 | */ | |
101 | ||
102 | u_char *session_id2 = NULL; | |
103 | u_int session_id2_len = 0; | |
104 | ||
105 | char *xxx_host; | |
106 | struct sockaddr *xxx_hostaddr; | |
107 | ||
108 | Kex *xxx_kex = NULL; | |
109 | ||
110 | static int | |
111 | verify_host_key_callback(Key *hostkey) | |
112 | { | |
113 | if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) | |
114 | fatal("Host key verification failed."); | |
115 | return 0; | |
116 | } | |
117 | ||
118 | void | |
119 | ssh_kex2(char *host, struct sockaddr *hostaddr) | |
120 | { | |
121 | Kex *kex; | |
122 | ||
123 | #ifdef GSSAPI | |
124 | char *orig = NULL, *gss = NULL; | |
125 | char *gss_host = NULL; | |
126 | #endif | |
127 | ||
128 | xxx_host = host; | |
129 | xxx_hostaddr = hostaddr; | |
130 | ||
131 | #ifdef GSSAPI | |
132 | if (options.gss_keyex) { | |
133 | /* Add the GSSAPI mechanisms currently supported on this | |
134 | * client to the key exchange algorithm proposal */ | |
135 | orig = myproposal[PROPOSAL_KEX_ALGS]; | |
136 | ||
137 | if (options.gss_trust_dns) | |
138 | gss_host = (char *)get_canonical_hostname(1); | |
139 | else | |
140 | gss_host = host; | |
141 | ||
142 | gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity); | |
143 | if (gss) { | |
144 | debug("Offering GSSAPI proposal: %s", gss); | |
145 | xasprintf(&myproposal[PROPOSAL_KEX_ALGS], | |
146 | "%s,%s", gss, orig); | |
147 | } | |
148 | } | |
149 | #endif | |
150 | ||
151 | if (options.ciphers == (char *)-1) { | |
152 | logit("No valid ciphers for protocol version 2 given, using defaults."); | |
153 | options.ciphers = NULL; | |
154 | } | |
155 | if (options.ciphers != NULL) { | |
156 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
157 | myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; | |
158 | } | |
159 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = | |
160 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); | |
161 | myproposal[PROPOSAL_ENC_ALGS_STOC] = | |
162 | compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); | |
163 | if (options.compression) { | |
164 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
165 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; | |
166 | } else { | |
167 | myproposal[PROPOSAL_COMP_ALGS_CTOS] = | |
168 | myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; | |
169 | } | |
170 | if (options.macs != NULL) { | |
171 | myproposal[PROPOSAL_MAC_ALGS_CTOS] = | |
172 | myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; | |
173 | } | |
174 | if (options.hostkeyalgorithms != NULL) | |
175 | myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = | |
176 | options.hostkeyalgorithms; | |
177 | ||
178 | #ifdef GSSAPI | |
179 | /* If we've got GSSAPI algorithms, then we also support the | |
180 | * 'null' hostkey, as a last resort */ | |
181 | if (options.gss_keyex && gss) { | |
182 | orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; | |
183 | xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], | |
184 | "%s,null", orig); | |
185 | xfree(gss); | |
186 | } | |
187 | #endif | |
188 | ||
189 | if (options.rekey_limit) | |
190 | packet_set_rekey_limit((u_int32_t)options.rekey_limit); | |
191 | ||
192 | /* start key exchange */ | |
193 | kex = kex_setup(myproposal); | |
194 | kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; | |
195 | kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; | |
196 | kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; | |
197 | kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; | |
198 | #ifdef GSSAPI | |
199 | if (options.gss_keyex) { | |
200 | kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client; | |
201 | kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client; | |
202 | kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client; | |
203 | } | |
204 | #endif | |
205 | kex->client_version_string=client_version_string; | |
206 | kex->server_version_string=server_version_string; | |
207 | kex->verify_host_key=&verify_host_key_callback; | |
208 | ||
209 | #ifdef GSSAPI | |
210 | if (options.gss_keyex) { | |
211 | kex->gss_deleg_creds = options.gss_deleg_creds; | |
212 | kex->gss_trust_dns = options.gss_trust_dns; | |
213 | kex->gss_client = options.gss_client_identity; | |
214 | kex->gss_host = gss_host; | |
215 | } | |
216 | #endif | |
217 | ||
218 | xxx_kex = kex; | |
219 | ||
220 | dispatch_run(DISPATCH_BLOCK, &kex->done, kex); | |
221 | ||
222 | session_id2 = kex->session_id; | |
223 | session_id2_len = kex->session_id_len; | |
224 | ||
225 | #ifdef DEBUG_KEXDH | |
226 | /* send 1st encrypted/maced/compressed message */ | |
227 | packet_start(SSH2_MSG_IGNORE); | |
228 | packet_put_cstring("markus"); | |
229 | packet_send(); | |
230 | packet_write_wait(); | |
231 | #endif | |
232 | } | |
233 | ||
234 | /* | |
235 | * Authenticate user | |
236 | */ | |
237 | ||
238 | typedef struct Authctxt Authctxt; | |
239 | typedef struct Authmethod Authmethod; | |
240 | typedef struct identity Identity; | |
241 | typedef struct idlist Idlist; | |
242 | ||
243 | struct identity { | |
244 | TAILQ_ENTRY(identity) next; | |
245 | AuthenticationConnection *ac; /* set if agent supports key */ | |
246 | Key *key; /* public/private key */ | |
247 | char *filename; /* comment for agent-only keys */ | |
248 | int tried; | |
249 | int isprivate; /* key points to the private key */ | |
250 | }; | |
251 | TAILQ_HEAD(idlist, identity); | |
252 | ||
253 | struct Authctxt { | |
254 | const char *server_user; | |
255 | const char *local_user; | |
256 | const char *host; | |
257 | const char *service; | |
258 | Authmethod *method; | |
259 | int success; | |
260 | char *authlist; | |
261 | /* pubkey */ | |
262 | Idlist keys; | |
263 | AuthenticationConnection *agent; | |
264 | /* hostbased */ | |
265 | Sensitive *sensitive; | |
266 | /* kbd-interactive */ | |
267 | int info_req_seen; | |
268 | /* generic */ | |
269 | void *methoddata; | |
270 | }; | |
271 | struct Authmethod { | |
272 | char *name; /* string to compare against server's list */ | |
273 | int (*userauth)(Authctxt *authctxt); | |
274 | void (*cleanup)(Authctxt *authctxt); | |
275 | int *enabled; /* flag in option struct that enables method */ | |
276 | int *batch_flag; /* flag in option struct that disables method */ | |
277 | }; | |
278 | ||
279 | void input_userauth_success(int, u_int32_t, void *); | |
280 | void input_userauth_failure(int, u_int32_t, void *); | |
281 | void input_userauth_banner(int, u_int32_t, void *); | |
282 | void input_userauth_error(int, u_int32_t, void *); | |
283 | void input_userauth_info_req(int, u_int32_t, void *); | |
284 | void input_userauth_pk_ok(int, u_int32_t, void *); | |
285 | void input_userauth_passwd_changereq(int, u_int32_t, void *); | |
286 | void input_userauth_jpake_server_step1(int, u_int32_t, void *); | |
287 | void input_userauth_jpake_server_step2(int, u_int32_t, void *); | |
288 | void input_userauth_jpake_server_confirm(int, u_int32_t, void *); | |
289 | ||
290 | int userauth_none(Authctxt *); | |
291 | int userauth_pubkey(Authctxt *); | |
292 | int userauth_passwd(Authctxt *); | |
293 | int userauth_kbdint(Authctxt *); | |
294 | int userauth_hostbased(Authctxt *); | |
295 | int userauth_jpake(Authctxt *); | |
296 | ||
297 | void userauth_jpake_cleanup(Authctxt *); | |
298 | ||
299 | #ifdef GSSAPI | |
300 | int userauth_external(Authctxt *authctxt); | |
301 | int userauth_gssapi(Authctxt *authctxt); | |
302 | int userauth_gssapi_with_mic(Authctxt *authctxt); | |
303 | int userauth_gssapi_without_mic(Authctxt *authctxt); | |
304 | void input_gssapi_response(int type, u_int32_t, void *); | |
305 | void input_gssapi_token(int type, u_int32_t, void *); | |
306 | void input_gssapi_hash(int type, u_int32_t, void *); | |
307 | void input_gssapi_error(int, u_int32_t, void *); | |
308 | void input_gssapi_errtok(int, u_int32_t, void *); | |
309 | int userauth_gsskeyex(Authctxt *authctxt); | |
310 | #endif | |
311 | ||
312 | void userauth(Authctxt *, char *); | |
313 | ||
314 | static int sign_and_send_pubkey(Authctxt *, Identity *); | |
315 | static void pubkey_prepare(Authctxt *); | |
316 | static void pubkey_cleanup(Authctxt *); | |
317 | static Key *load_identity_file(char *); | |
318 | ||
319 | static Authmethod *authmethod_get(char *authlist); | |
320 | static Authmethod *authmethod_lookup(const char *name); | |
321 | static char *authmethods_get(void); | |
322 | ||
323 | Authmethod authmethods[] = { | |
324 | #ifdef GSSAPI | |
325 | {"gssapi-keyex", | |
326 | userauth_gsskeyex, | |
327 | NULL, | |
328 | &options.gss_authentication, | |
329 | NULL}, | |
330 | {"external-keyx", | |
331 | userauth_external, | |
332 | NULL, | |
333 | &options.gss_authentication, | |
334 | NULL}, | |
335 | {"gssapi-with-mic", | |
336 | userauth_gssapi, | |
337 | NULL, | |
338 | &options.gss_authentication, | |
339 | NULL}, | |
340 | {"gssapi", | |
341 | userauth_gssapi, | |
342 | NULL, | |
343 | &options.gss_authentication, | |
344 | NULL}, | |
345 | #endif | |
346 | {"hostbased", | |
347 | userauth_hostbased, | |
348 | NULL, | |
349 | &options.hostbased_authentication, | |
350 | NULL}, | |
351 | {"publickey", | |
352 | userauth_pubkey, | |
353 | NULL, | |
354 | &options.pubkey_authentication, | |
355 | NULL}, | |
356 | #ifdef JPAKE | |
357 | {"jpake-01@openssh.com", | |
358 | userauth_jpake, | |
359 | userauth_jpake_cleanup, | |
360 | &options.zero_knowledge_password_authentication, | |
361 | &options.batch_mode}, | |
362 | #endif | |
363 | {"keyboard-interactive", | |
364 | userauth_kbdint, | |
365 | NULL, | |
366 | &options.kbd_interactive_authentication, | |
367 | &options.batch_mode}, | |
368 | {"password", | |
369 | userauth_passwd, | |
370 | NULL, | |
371 | &options.password_authentication, | |
372 | &options.batch_mode}, | |
373 | {"none", | |
374 | userauth_none, | |
375 | NULL, | |
376 | NULL, | |
377 | NULL}, | |
378 | {NULL, NULL, NULL, NULL, NULL} | |
379 | }; | |
380 | ||
381 | void | |
382 | ssh_userauth2(const char *local_user, const char *server_user, char *host, | |
383 | Sensitive *sensitive) | |
384 | { | |
385 | Authctxt authctxt; | |
386 | int type; | |
387 | ||
388 | if (options.challenge_response_authentication) | |
389 | options.kbd_interactive_authentication = 1; | |
390 | ||
391 | packet_start(SSH2_MSG_SERVICE_REQUEST); | |
392 | packet_put_cstring("ssh-userauth"); | |
393 | packet_send(); | |
394 | debug("SSH2_MSG_SERVICE_REQUEST sent"); | |
395 | packet_write_wait(); | |
396 | type = packet_read(); | |
397 | if (type != SSH2_MSG_SERVICE_ACCEPT) | |
398 | fatal("Server denied authentication request: %d", type); | |
399 | if (packet_remaining() > 0) { | |
400 | char *reply = packet_get_string(NULL); | |
401 | debug2("service_accept: %s", reply); | |
402 | xfree(reply); | |
403 | } else { | |
404 | debug2("buggy server: service_accept w/o service"); | |
405 | } | |
406 | packet_check_eom(); | |
407 | debug("SSH2_MSG_SERVICE_ACCEPT received"); | |
408 | ||
409 | if (options.preferred_authentications == NULL) | |
410 | options.preferred_authentications = authmethods_get(); | |
411 | ||
412 | /* setup authentication context */ | |
413 | memset(&authctxt, 0, sizeof(authctxt)); | |
414 | pubkey_prepare(&authctxt); | |
415 | authctxt.server_user = server_user; | |
416 | authctxt.local_user = local_user; | |
417 | authctxt.host = host; | |
418 | authctxt.service = "ssh-connection"; /* service name */ | |
419 | authctxt.success = 0; | |
420 | authctxt.method = authmethod_lookup("none"); | |
421 | authctxt.authlist = NULL; | |
422 | authctxt.methoddata = NULL; | |
423 | authctxt.sensitive = sensitive; | |
424 | authctxt.info_req_seen = 0; | |
425 | if (authctxt.method == NULL) | |
426 | fatal("ssh_userauth2: internal error: cannot send userauth none request"); | |
427 | ||
428 | /* initial userauth request */ | |
429 | userauth_none(&authctxt); | |
430 | ||
431 | dispatch_init(&input_userauth_error); | |
432 | dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); | |
433 | dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); | |
434 | dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); | |
435 | dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ | |
436 | ||
437 | pubkey_cleanup(&authctxt); | |
438 | dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); | |
439 | ||
440 | /* if the user wants to use the none cipher do it */ | |
441 | /* post authentication and only if the right conditions are met */ | |
442 | /* both of the NONE commands must be true and there must be no */ | |
443 | /* tty allocated */ | |
444 | if ((options.none_switch == 1) && (options.none_enabled == 1)) | |
445 | { | |
446 | if (!tty_flag) /* no null on tty sessions */ | |
447 | { | |
448 | debug("Requesting none rekeying..."); | |
449 | myproposal[PROPOSAL_ENC_ALGS_STOC] = "none"; | |
450 | myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none"; | |
451 | kex_prop2buf(&xxx_kex->my,myproposal); | |
452 | packet_request_rekeying(); | |
453 | fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n"); | |
454 | } | |
455 | else | |
456 | { | |
457 | /* requested NONE cipher when in a tty */ | |
458 | debug("Cannot switch to NONE cipher with tty allocated"); | |
459 | fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n"); | |
460 | } | |
461 | } | |
462 | debug("Authentication succeeded (%s).", authctxt.method->name); | |
463 | } | |
464 | ||
465 | void | |
466 | userauth(Authctxt *authctxt, char *authlist) | |
467 | { | |
468 | if (authctxt->method != NULL && authctxt->method->cleanup != NULL) | |
469 | authctxt->method->cleanup(authctxt); | |
470 | ||
471 | if (authctxt->methoddata) { | |
472 | xfree(authctxt->methoddata); | |
473 | authctxt->methoddata = NULL; | |
474 | } | |
475 | if (authlist == NULL) { | |
476 | authlist = authctxt->authlist; | |
477 | } else { | |
478 | if (authctxt->authlist) | |
479 | xfree(authctxt->authlist); | |
480 | authctxt->authlist = authlist; | |
481 | } | |
482 | for (;;) { | |
483 | Authmethod *method = authmethod_get(authlist); | |
484 | if (method == NULL) | |
485 | fatal("Permission denied (%s).", authlist); | |
486 | authctxt->method = method; | |
487 | ||
488 | /* reset the per method handler */ | |
489 | dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, | |
490 | SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); | |
491 | ||
492 | /* and try new method */ | |
493 | if (method->userauth(authctxt) != 0) { | |
494 | debug2("we sent a %s packet, wait for reply", method->name); | |
495 | break; | |
496 | } else { | |
497 | debug2("we did not send a packet, disable method"); | |
498 | method->enabled = NULL; | |
499 | } | |
500 | } | |
501 | } | |
502 | ||
503 | /* ARGSUSED */ | |
504 | void | |
505 | input_userauth_error(int type, u_int32_t seq, void *ctxt) | |
506 | { | |
507 | fatal("input_userauth_error: bad message during authentication: " | |
508 | "type %d", type); | |
509 | } | |
510 | ||
511 | /* ARGSUSED */ | |
512 | void | |
513 | input_userauth_banner(int type, u_int32_t seq, void *ctxt) | |
514 | { | |
515 | char *msg, *raw, *lang; | |
516 | u_int len; | |
517 | ||
518 | debug3("input_userauth_banner"); | |
519 | raw = packet_get_string(&len); | |
520 | lang = packet_get_string(NULL); | |
521 | if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { | |
522 | if (len > 65536) | |
523 | len = 65536; | |
524 | msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ | |
525 | strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL); | |
526 | fprintf(stderr, "%s", msg); | |
527 | xfree(msg); | |
528 | } | |
529 | xfree(raw); | |
530 | xfree(lang); | |
531 | } | |
532 | ||
533 | /* ARGSUSED */ | |
534 | void | |
535 | input_userauth_success(int type, u_int32_t seq, void *ctxt) | |
536 | { | |
537 | Authctxt *authctxt = ctxt; | |
538 | if (authctxt == NULL) | |
539 | fatal("input_userauth_success: no authentication context"); | |
540 | if (authctxt->authlist) { | |
541 | xfree(authctxt->authlist); | |
542 | authctxt->authlist = NULL; | |
543 | } | |
544 | if (authctxt->methoddata) { | |
545 | xfree(authctxt->methoddata); | |
546 | authctxt->methoddata = NULL; | |
547 | } | |
548 | authctxt->success = 1; /* break out */ | |
549 | } | |
550 | ||
551 | /* ARGSUSED */ | |
552 | void | |
553 | input_userauth_failure(int type, u_int32_t seq, void *ctxt) | |
554 | { | |
555 | Authctxt *authctxt = ctxt; | |
556 | char *authlist = NULL; | |
557 | int partial; | |
558 | ||
559 | if (authctxt == NULL) | |
560 | fatal("input_userauth_failure: no authentication context"); | |
561 | ||
562 | authlist = packet_get_string(NULL); | |
563 | partial = packet_get_char(); | |
564 | packet_check_eom(); | |
565 | ||
566 | if (partial != 0) | |
567 | logit("Authenticated with partial success."); | |
568 | debug("Authentications that can continue: %s", authlist); | |
569 | ||
570 | userauth(authctxt, authlist); | |
571 | } | |
572 | ||
573 | /* ARGSUSED */ | |
574 | void | |
575 | input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) | |
576 | { | |
577 | Authctxt *authctxt = ctxt; | |
578 | Key *key = NULL; | |
579 | Identity *id = NULL; | |
580 | Buffer b; | |
581 | int pktype, sent = 0; | |
582 | u_int alen, blen; | |
583 | char *pkalg, *fp; | |
584 | u_char *pkblob; | |
585 | ||
586 | if (authctxt == NULL) | |
587 | fatal("input_userauth_pk_ok: no authentication context"); | |
588 | if (datafellows & SSH_BUG_PKOK) { | |
589 | /* this is similar to SSH_BUG_PKAUTH */ | |
590 | debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); | |
591 | pkblob = packet_get_string(&blen); | |
592 | buffer_init(&b); | |
593 | buffer_append(&b, pkblob, blen); | |
594 | pkalg = buffer_get_string(&b, &alen); | |
595 | buffer_free(&b); | |
596 | } else { | |
597 | pkalg = packet_get_string(&alen); | |
598 | pkblob = packet_get_string(&blen); | |
599 | } | |
600 | packet_check_eom(); | |
601 | ||
602 | debug("Server accepts key: pkalg %s blen %u", pkalg, blen); | |
603 | ||
604 | if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { | |
605 | debug("unknown pkalg %s", pkalg); | |
606 | goto done; | |
607 | } | |
608 | if ((key = key_from_blob(pkblob, blen)) == NULL) { | |
609 | debug("no key from blob. pkalg %s", pkalg); | |
610 | goto done; | |
611 | } | |
612 | if (key->type != pktype) { | |
613 | error("input_userauth_pk_ok: type mismatch " | |
614 | "for decoded key (received %d, expected %d)", | |
615 | key->type, pktype); | |
616 | goto done; | |
617 | } | |
618 | fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); | |
619 | debug2("input_userauth_pk_ok: fp %s", fp); | |
620 | xfree(fp); | |
621 | ||
622 | /* | |
623 | * search keys in the reverse order, because last candidate has been | |
624 | * moved to the end of the queue. this also avoids confusion by | |
625 | * duplicate keys | |
626 | */ | |
627 | TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { | |
628 | if (key_equal(key, id->key)) { | |
629 | sent = sign_and_send_pubkey(authctxt, id); | |
630 | break; | |
631 | } | |
632 | } | |
633 | done: | |
634 | if (key != NULL) | |
635 | key_free(key); | |
636 | xfree(pkalg); | |
637 | xfree(pkblob); | |
638 | ||
639 | /* try another method if we did not send a packet */ | |
640 | if (sent == 0) | |
641 | userauth(authctxt, NULL); | |
642 | } | |
643 | ||
644 | #ifdef GSSAPI | |
645 | int | |
646 | userauth_gssapi(Authctxt *authctxt) | |
647 | { | |
648 | Gssctxt *gssctxt = NULL; | |
649 | static gss_OID_set gss_supported = NULL; | |
650 | static u_int mech = 0; | |
651 | OM_uint32 min; | |
652 | int ok = 0; | |
653 | char *gss_host = NULL; | |
654 | ||
655 | if (!options.gss_authentication) { | |
656 | verbose("GSSAPI authentication disabled."); | |
657 | return 0; | |
658 | } | |
659 | ||
660 | if (options.gss_trust_dns) | |
661 | gss_host = (char *)get_canonical_hostname(1); | |
662 | else | |
663 | gss_host = (char *)authctxt->host; | |
664 | ||
665 | /* Try one GSSAPI method at a time, rather than sending them all at | |
666 | * once. */ | |
667 | ||
668 | if (gss_supported == NULL) | |
669 | if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) { | |
670 | gss_supported = NULL; | |
671 | return 0; | |
672 | } | |
673 | ||
674 | /* Check to see if the mechanism is usable before we offer it */ | |
675 | while (mech < gss_supported->count && !ok) { | |
676 | /* My DER encoding requires length<128 */ | |
677 | if (gss_supported->elements[mech].length < 128 && | |
678 | ssh_gssapi_check_mechanism(&gssctxt, | |
679 | &gss_supported->elements[mech], gss_host, | |
680 | options.gss_client_identity)) { | |
681 | ok = 1; /* Mechanism works */ | |
682 | } else { | |
683 | mech++; | |
684 | } | |
685 | } | |
686 | ||
687 | if (!ok) | |
688 | return 0; | |
689 | ||
690 | authctxt->methoddata=(void *)gssctxt; | |
691 | ||
692 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
693 | packet_put_cstring(authctxt->server_user); | |
694 | packet_put_cstring(authctxt->service); | |
695 | packet_put_cstring(authctxt->method->name); | |
696 | ||
697 | packet_put_int(1); | |
698 | ||
699 | packet_put_int((gss_supported->elements[mech].length) + 2); | |
700 | packet_put_char(SSH_GSS_OIDTYPE); | |
701 | packet_put_char(gss_supported->elements[mech].length); | |
702 | packet_put_raw(gss_supported->elements[mech].elements, | |
703 | gss_supported->elements[mech].length); | |
704 | ||
705 | packet_send(); | |
706 | ||
707 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); | |
708 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); | |
709 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); | |
710 | dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); | |
711 | ||
712 | mech++; /* Move along to next candidate */ | |
713 | ||
714 | return 1; | |
715 | } | |
716 | ||
717 | static OM_uint32 | |
718 | process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) | |
719 | { | |
720 | Authctxt *authctxt = ctxt; | |
721 | Gssctxt *gssctxt = authctxt->methoddata; | |
722 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | |
723 | gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; | |
724 | gss_buffer_desc gssbuf; | |
725 | OM_uint32 status, ms, flags; | |
726 | Buffer b; | |
727 | ||
728 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, | |
729 | recv_tok, &send_tok, &flags); | |
730 | ||
731 | if (send_tok.length > 0) { | |
732 | if (GSS_ERROR(status)) | |
733 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); | |
734 | else | |
735 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); | |
736 | ||
737 | packet_put_string(send_tok.value, send_tok.length); | |
738 | packet_send(); | |
739 | gss_release_buffer(&ms, &send_tok); | |
740 | } | |
741 | ||
742 | if (status == GSS_S_COMPLETE) { | |
743 | /* send either complete or MIC, depending on mechanism */ | |
744 | if (strcmp(authctxt->method->name,"gssapi")==0 || | |
745 | (!(flags & GSS_C_INTEG_FLAG))) { | |
746 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); | |
747 | packet_send(); | |
748 | } else { | |
749 | ssh_gssapi_buildmic(&b, authctxt->server_user, | |
750 | authctxt->service, "gssapi-with-mic"); | |
751 | ||
752 | gssbuf.value = buffer_ptr(&b); | |
753 | gssbuf.length = buffer_len(&b); | |
754 | ||
755 | status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); | |
756 | ||
757 | if (!GSS_ERROR(status)) { | |
758 | packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); | |
759 | packet_put_string(mic.value, mic.length); | |
760 | ||
761 | packet_send(); | |
762 | } | |
763 | ||
764 | buffer_free(&b); | |
765 | gss_release_buffer(&ms, &mic); | |
766 | } | |
767 | } | |
768 | ||
769 | return status; | |
770 | } | |
771 | ||
772 | /* ARGSUSED */ | |
773 | void | |
774 | input_gssapi_response(int type, u_int32_t plen, void *ctxt) | |
775 | { | |
776 | Authctxt *authctxt = ctxt; | |
777 | Gssctxt *gssctxt; | |
778 | u_int oidlen; | |
779 | u_char *oidv; | |
780 | ||
781 | if (authctxt == NULL) | |
782 | fatal("input_gssapi_response: no authentication context"); | |
783 | gssctxt = authctxt->methoddata; | |
784 | ||
785 | /* Setup our OID */ | |
786 | oidv = packet_get_string(&oidlen); | |
787 | ||
788 | if (oidlen <= 2 || | |
789 | oidv[0] != SSH_GSS_OIDTYPE || | |
790 | oidv[1] != oidlen - 2) { | |
791 | xfree(oidv); | |
792 | debug("Badly encoded mechanism OID received"); | |
793 | userauth(authctxt, NULL); | |
794 | return; | |
795 | } | |
796 | ||
797 | if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) | |
798 | fatal("Server returned different OID than expected"); | |
799 | ||
800 | packet_check_eom(); | |
801 | ||
802 | xfree(oidv); | |
803 | ||
804 | if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { | |
805 | /* Start again with next method on list */ | |
806 | debug("Trying to start again"); | |
807 | userauth(authctxt, NULL); | |
808 | return; | |
809 | } | |
810 | } | |
811 | ||
812 | /* ARGSUSED */ | |
813 | void | |
814 | input_gssapi_token(int type, u_int32_t plen, void *ctxt) | |
815 | { | |
816 | Authctxt *authctxt = ctxt; | |
817 | gss_buffer_desc recv_tok; | |
818 | OM_uint32 status; | |
819 | u_int slen; | |
820 | ||
821 | if (authctxt == NULL) | |
822 | fatal("input_gssapi_response: no authentication context"); | |
823 | ||
824 | recv_tok.value = packet_get_string(&slen); | |
825 | recv_tok.length = slen; /* safe typecast */ | |
826 | ||
827 | packet_check_eom(); | |
828 | ||
829 | status = process_gssapi_token(ctxt, &recv_tok); | |
830 | ||
831 | xfree(recv_tok.value); | |
832 | ||
833 | if (GSS_ERROR(status)) { | |
834 | /* Start again with the next method in the list */ | |
835 | userauth(authctxt, NULL); | |
836 | return; | |
837 | } | |
838 | } | |
839 | ||
840 | /* ARGSUSED */ | |
841 | void | |
842 | input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) | |
843 | { | |
844 | Authctxt *authctxt = ctxt; | |
845 | Gssctxt *gssctxt; | |
846 | gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; | |
847 | gss_buffer_desc recv_tok; | |
848 | OM_uint32 status, ms; | |
849 | u_int len; | |
850 | ||
851 | if (authctxt == NULL) | |
852 | fatal("input_gssapi_response: no authentication context"); | |
853 | gssctxt = authctxt->methoddata; | |
854 | ||
855 | recv_tok.value = packet_get_string(&len); | |
856 | recv_tok.length = len; | |
857 | ||
858 | packet_check_eom(); | |
859 | ||
860 | /* Stick it into GSSAPI and see what it says */ | |
861 | status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, | |
862 | &recv_tok, &send_tok, NULL); | |
863 | ||
864 | xfree(recv_tok.value); | |
865 | gss_release_buffer(&ms, &send_tok); | |
866 | ||
867 | /* Server will be returning a failed packet after this one */ | |
868 | } | |
869 | ||
870 | /* ARGSUSED */ | |
871 | void | |
872 | input_gssapi_error(int type, u_int32_t plen, void *ctxt) | |
873 | { | |
874 | OM_uint32 maj, min; | |
875 | char *msg; | |
876 | char *lang; | |
877 | ||
878 | maj=packet_get_int(); | |
879 | min=packet_get_int(); | |
880 | msg=packet_get_string(NULL); | |
881 | lang=packet_get_string(NULL); | |
882 | ||
883 | packet_check_eom(); | |
884 | ||
885 | debug("Server GSSAPI Error:\n%s", msg); | |
886 | xfree(msg); | |
887 | xfree(lang); | |
888 | } | |
889 | ||
890 | #ifdef GSI | |
891 | extern | |
892 | const gss_OID_desc * const gss_mech_globus_gssapi_openssl; | |
893 | #define is_gsi_oid(oid) \ | |
894 | (oid->length == gss_mech_globus_gssapi_openssl->length && \ | |
895 | (memcmp(oid->elements, gss_mech_globus_gssapi_openssl->elements, \ | |
896 | oid->length) == 0)) | |
897 | #endif | |
898 | ||
899 | int | |
900 | userauth_external(Authctxt *authctxt) | |
901 | { | |
902 | static int attempt = 0; | |
903 | ||
904 | if (attempt++ >= 1) | |
905 | return 0; | |
906 | ||
907 | /* The client MUST NOT try this method if initial key exchange | |
908 | was not performed using a GSSAPI-based key exchange | |
909 | method. */ | |
910 | if (gss_kex_context == NULL) { | |
911 | debug2("gsskex not performed, skipping external-keyx"); | |
912 | return 0; | |
913 | } | |
914 | ||
915 | debug2("userauth_external"); | |
916 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
917 | #ifdef GSI | |
918 | if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { | |
919 | packet_put_cstring(""); | |
920 | } else { | |
921 | #endif | |
922 | packet_put_cstring(authctxt->server_user); | |
923 | #ifdef GSI | |
924 | } | |
925 | #endif | |
926 | packet_put_cstring(authctxt->service); | |
927 | packet_put_cstring(authctxt->method->name); | |
928 | packet_send(); | |
929 | packet_write_wait(); | |
930 | return 1; | |
931 | } | |
932 | int | |
933 | userauth_gsskeyex(Authctxt *authctxt) | |
934 | { | |
935 | Buffer b; | |
936 | gss_buffer_desc gssbuf; | |
937 | gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; | |
938 | OM_uint32 ms; | |
939 | ||
940 | static int attempt = 0; | |
941 | if (attempt++ >= 1) | |
942 | return (0); | |
943 | ||
944 | if (gss_kex_context == NULL) { | |
945 | debug("No valid Key exchange context"); | |
946 | return (0); | |
947 | } | |
948 | ||
949 | #ifdef GSI | |
950 | if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { | |
951 | ssh_gssapi_buildmic(&b, "", authctxt->service, "gssapi-keyex"); | |
952 | } else { | |
953 | #endif | |
954 | ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service, | |
955 | "gssapi-keyex"); | |
956 | #ifdef GSI | |
957 | } | |
958 | #endif | |
959 | ||
960 | gssbuf.value = buffer_ptr(&b); | |
961 | gssbuf.length = buffer_len(&b); | |
962 | ||
963 | if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) { | |
964 | buffer_free(&b); | |
965 | return (0); | |
966 | } | |
967 | ||
968 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
969 | #ifdef GSI | |
970 | if (options.implicit && is_gsi_oid(gss_kex_context->oid)) { | |
971 | packet_put_cstring(""); | |
972 | } else { | |
973 | #endif | |
974 | packet_put_cstring(authctxt->server_user); | |
975 | #ifdef GSI | |
976 | } | |
977 | #endif | |
978 | packet_put_cstring(authctxt->service); | |
979 | packet_put_cstring(authctxt->method->name); | |
980 | packet_put_string(mic.value, mic.length); | |
981 | packet_send(); | |
982 | ||
983 | buffer_free(&b); | |
984 | gss_release_buffer(&ms, &mic); | |
985 | ||
986 | return (1); | |
987 | } | |
988 | ||
989 | #endif /* GSSAPI */ | |
990 | ||
991 | int | |
992 | userauth_none(Authctxt *authctxt) | |
993 | { | |
994 | /* initial userauth request */ | |
995 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
996 | packet_put_cstring(authctxt->server_user); | |
997 | packet_put_cstring(authctxt->service); | |
998 | packet_put_cstring(authctxt->method->name); | |
999 | packet_send(); | |
1000 | return 1; | |
1001 | } | |
1002 | ||
1003 | int | |
1004 | userauth_passwd(Authctxt *authctxt) | |
1005 | { | |
1006 | static int attempt = 0; | |
1007 | char prompt[150]; | |
1008 | char *password; | |
1009 | ||
1010 | if (attempt++ >= options.number_of_password_prompts) | |
1011 | return 0; | |
1012 | ||
1013 | if (attempt != 1) | |
1014 | error("Permission denied, please try again."); | |
1015 | ||
1016 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", | |
1017 | authctxt->server_user, authctxt->host); | |
1018 | password = read_passphrase(prompt, 0); | |
1019 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1020 | packet_put_cstring(authctxt->server_user); | |
1021 | packet_put_cstring(authctxt->service); | |
1022 | packet_put_cstring(authctxt->method->name); | |
1023 | packet_put_char(0); | |
1024 | packet_put_cstring(password); | |
1025 | memset(password, 0, strlen(password)); | |
1026 | xfree(password); | |
1027 | packet_add_padding(64); | |
1028 | packet_send(); | |
1029 | ||
1030 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, | |
1031 | &input_userauth_passwd_changereq); | |
1032 | ||
1033 | return 1; | |
1034 | } | |
1035 | ||
1036 | /* | |
1037 | * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST | |
1038 | */ | |
1039 | /* ARGSUSED */ | |
1040 | void | |
1041 | input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) | |
1042 | { | |
1043 | Authctxt *authctxt = ctxt; | |
1044 | char *info, *lang, *password = NULL, *retype = NULL; | |
1045 | char prompt[150]; | |
1046 | ||
1047 | debug2("input_userauth_passwd_changereq"); | |
1048 | ||
1049 | if (authctxt == NULL) | |
1050 | fatal("input_userauth_passwd_changereq: " | |
1051 | "no authentication context"); | |
1052 | ||
1053 | info = packet_get_string(NULL); | |
1054 | lang = packet_get_string(NULL); | |
1055 | if (strlen(info) > 0) | |
1056 | logit("%s", info); | |
1057 | xfree(info); | |
1058 | xfree(lang); | |
1059 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1060 | packet_put_cstring(authctxt->server_user); | |
1061 | packet_put_cstring(authctxt->service); | |
1062 | packet_put_cstring(authctxt->method->name); | |
1063 | packet_put_char(1); /* additional info */ | |
1064 | snprintf(prompt, sizeof(prompt), | |
1065 | "Enter %.30s@%.128s's old password: ", | |
1066 | authctxt->server_user, authctxt->host); | |
1067 | password = read_passphrase(prompt, 0); | |
1068 | packet_put_cstring(password); | |
1069 | memset(password, 0, strlen(password)); | |
1070 | xfree(password); | |
1071 | password = NULL; | |
1072 | while (password == NULL) { | |
1073 | snprintf(prompt, sizeof(prompt), | |
1074 | "Enter %.30s@%.128s's new password: ", | |
1075 | authctxt->server_user, authctxt->host); | |
1076 | password = read_passphrase(prompt, RP_ALLOW_EOF); | |
1077 | if (password == NULL) { | |
1078 | /* bail out */ | |
1079 | return; | |
1080 | } | |
1081 | snprintf(prompt, sizeof(prompt), | |
1082 | "Retype %.30s@%.128s's new password: ", | |
1083 | authctxt->server_user, authctxt->host); | |
1084 | retype = read_passphrase(prompt, 0); | |
1085 | if (strcmp(password, retype) != 0) { | |
1086 | memset(password, 0, strlen(password)); | |
1087 | xfree(password); | |
1088 | logit("Mismatch; try again, EOF to quit."); | |
1089 | password = NULL; | |
1090 | } | |
1091 | memset(retype, 0, strlen(retype)); | |
1092 | xfree(retype); | |
1093 | } | |
1094 | packet_put_cstring(password); | |
1095 | memset(password, 0, strlen(password)); | |
1096 | xfree(password); | |
1097 | packet_add_padding(64); | |
1098 | packet_send(); | |
1099 | ||
1100 | dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, | |
1101 | &input_userauth_passwd_changereq); | |
1102 | } | |
1103 | ||
1104 | #ifdef JPAKE | |
1105 | static char * | |
1106 | pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) | |
1107 | { | |
1108 | /* OpenBSD crypt(3) handles all of these */ | |
1109 | if (strcmp(crypt_scheme, "crypt") == 0 || | |
1110 | strcmp(crypt_scheme, "bcrypt") == 0 || | |
1111 | strcmp(crypt_scheme, "md5crypt") == 0 || | |
1112 | strcmp(crypt_scheme, "crypt-extended") == 0) | |
1113 | return xstrdup(crypt(password, salt)); | |
1114 | error("%s: unsupported password encryption scheme \"%.100s\"", | |
1115 | __func__, crypt_scheme); | |
1116 | return NULL; | |
1117 | } | |
1118 | ||
1119 | static BIGNUM * | |
1120 | jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, | |
1121 | const char *salt) | |
1122 | { | |
1123 | char prompt[256], *password, *crypted; | |
1124 | u_char *secret; | |
1125 | u_int secret_len; | |
1126 | BIGNUM *ret; | |
1127 | ||
1128 | snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", | |
1129 | authctxt->server_user, authctxt->host); | |
1130 | password = read_passphrase(prompt, 0); | |
1131 | ||
1132 | if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { | |
1133 | logit("Disabling %s authentication", authctxt->method->name); | |
1134 | authctxt->method->enabled = NULL; | |
1135 | /* Continue with an empty password to fail gracefully */ | |
1136 | crypted = xstrdup(""); | |
1137 | } | |
1138 | ||
1139 | #ifdef JPAKE_DEBUG | |
1140 | debug3("%s: salt = %s", __func__, salt); | |
1141 | debug3("%s: scheme = %s", __func__, crypt_scheme); | |
1142 | debug3("%s: crypted = %s", __func__, crypted); | |
1143 | #endif | |
1144 | ||
1145 | if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), | |
1146 | &secret, &secret_len) != 0) | |
1147 | fatal("%s: hash_buffer", __func__); | |
1148 | ||
1149 | bzero(password, strlen(password)); | |
1150 | bzero(crypted, strlen(crypted)); | |
1151 | xfree(password); | |
1152 | xfree(crypted); | |
1153 | ||
1154 | if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) | |
1155 | fatal("%s: BN_bin2bn (secret)", __func__); | |
1156 | bzero(secret, secret_len); | |
1157 | xfree(secret); | |
1158 | ||
1159 | return ret; | |
1160 | } | |
1161 | ||
1162 | /* ARGSUSED */ | |
1163 | void | |
1164 | input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) | |
1165 | { | |
1166 | Authctxt *authctxt = ctxt; | |
1167 | struct jpake_ctx *pctx = authctxt->methoddata; | |
1168 | u_char *x3_proof, *x4_proof, *x2_s_proof; | |
1169 | u_int x3_proof_len, x4_proof_len, x2_s_proof_len; | |
1170 | char *crypt_scheme, *salt; | |
1171 | ||
1172 | /* Disable this message */ | |
1173 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); | |
1174 | ||
1175 | if ((pctx->g_x3 = BN_new()) == NULL || | |
1176 | (pctx->g_x4 = BN_new()) == NULL) | |
1177 | fatal("%s: BN_new", __func__); | |
1178 | ||
1179 | /* Fetch step 1 values */ | |
1180 | crypt_scheme = packet_get_string(NULL); | |
1181 | salt = packet_get_string(NULL); | |
1182 | pctx->server_id = packet_get_string(&pctx->server_id_len); | |
1183 | packet_get_bignum2(pctx->g_x3); | |
1184 | packet_get_bignum2(pctx->g_x4); | |
1185 | x3_proof = packet_get_string(&x3_proof_len); | |
1186 | x4_proof = packet_get_string(&x4_proof_len); | |
1187 | packet_check_eom(); | |
1188 | ||
1189 | JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); | |
1190 | ||
1191 | /* Obtain password and derive secret */ | |
1192 | pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); | |
1193 | bzero(crypt_scheme, strlen(crypt_scheme)); | |
1194 | bzero(salt, strlen(salt)); | |
1195 | xfree(crypt_scheme); | |
1196 | xfree(salt); | |
1197 | JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); | |
1198 | ||
1199 | /* Calculate step 2 values */ | |
1200 | jpake_step2(pctx->grp, pctx->s, pctx->g_x1, | |
1201 | pctx->g_x3, pctx->g_x4, pctx->x2, | |
1202 | pctx->server_id, pctx->server_id_len, | |
1203 | pctx->client_id, pctx->client_id_len, | |
1204 | x3_proof, x3_proof_len, | |
1205 | x4_proof, x4_proof_len, | |
1206 | &pctx->a, | |
1207 | &x2_s_proof, &x2_s_proof_len); | |
1208 | ||
1209 | bzero(x3_proof, x3_proof_len); | |
1210 | bzero(x4_proof, x4_proof_len); | |
1211 | xfree(x3_proof); | |
1212 | xfree(x4_proof); | |
1213 | ||
1214 | JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); | |
1215 | ||
1216 | /* Send values for step 2 */ | |
1217 | packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); | |
1218 | packet_put_bignum2(pctx->a); | |
1219 | packet_put_string(x2_s_proof, x2_s_proof_len); | |
1220 | packet_send(); | |
1221 | ||
1222 | bzero(x2_s_proof, x2_s_proof_len); | |
1223 | xfree(x2_s_proof); | |
1224 | ||
1225 | /* Expect step 2 packet from peer */ | |
1226 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, | |
1227 | input_userauth_jpake_server_step2); | |
1228 | } | |
1229 | ||
1230 | /* ARGSUSED */ | |
1231 | void | |
1232 | input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) | |
1233 | { | |
1234 | Authctxt *authctxt = ctxt; | |
1235 | struct jpake_ctx *pctx = authctxt->methoddata; | |
1236 | u_char *x4_s_proof; | |
1237 | u_int x4_s_proof_len; | |
1238 | ||
1239 | /* Disable this message */ | |
1240 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); | |
1241 | ||
1242 | if ((pctx->b = BN_new()) == NULL) | |
1243 | fatal("%s: BN_new", __func__); | |
1244 | ||
1245 | /* Fetch step 2 values */ | |
1246 | packet_get_bignum2(pctx->b); | |
1247 | x4_s_proof = packet_get_string(&x4_s_proof_len); | |
1248 | packet_check_eom(); | |
1249 | ||
1250 | JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); | |
1251 | ||
1252 | /* Derive shared key and calculate confirmation hash */ | |
1253 | jpake_key_confirm(pctx->grp, pctx->s, pctx->b, | |
1254 | pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, | |
1255 | pctx->client_id, pctx->client_id_len, | |
1256 | pctx->server_id, pctx->server_id_len, | |
1257 | session_id2, session_id2_len, | |
1258 | x4_s_proof, x4_s_proof_len, | |
1259 | &pctx->k, | |
1260 | &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); | |
1261 | ||
1262 | bzero(x4_s_proof, x4_s_proof_len); | |
1263 | xfree(x4_s_proof); | |
1264 | ||
1265 | JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); | |
1266 | ||
1267 | /* Send key confirmation proof */ | |
1268 | packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); | |
1269 | packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); | |
1270 | packet_send(); | |
1271 | ||
1272 | /* Expect confirmation from peer */ | |
1273 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, | |
1274 | input_userauth_jpake_server_confirm); | |
1275 | } | |
1276 | ||
1277 | /* ARGSUSED */ | |
1278 | void | |
1279 | input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) | |
1280 | { | |
1281 | Authctxt *authctxt = ctxt; | |
1282 | struct jpake_ctx *pctx = authctxt->methoddata; | |
1283 | ||
1284 | /* Disable this message */ | |
1285 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); | |
1286 | ||
1287 | pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); | |
1288 | packet_check_eom(); | |
1289 | ||
1290 | JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); | |
1291 | ||
1292 | /* Verify expected confirmation hash */ | |
1293 | if (jpake_check_confirm(pctx->k, | |
1294 | pctx->server_id, pctx->server_id_len, | |
1295 | session_id2, session_id2_len, | |
1296 | pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) | |
1297 | debug("%s: %s success", __func__, authctxt->method->name); | |
1298 | else { | |
1299 | debug("%s: confirmation mismatch", __func__); | |
1300 | /* XXX stash this so if auth succeeds then we can warn/kill */ | |
1301 | } | |
1302 | ||
1303 | userauth_jpake_cleanup(authctxt); | |
1304 | } | |
1305 | #endif /* JPAKE */ | |
1306 | ||
1307 | static int | |
1308 | identity_sign(Identity *id, u_char **sigp, u_int *lenp, | |
1309 | u_char *data, u_int datalen) | |
1310 | { | |
1311 | Key *prv; | |
1312 | int ret; | |
1313 | ||
1314 | /* the agent supports this key */ | |
1315 | if (id->ac) | |
1316 | return (ssh_agent_sign(id->ac, id->key, sigp, lenp, | |
1317 | data, datalen)); | |
1318 | /* | |
1319 | * we have already loaded the private key or | |
1320 | * the private key is stored in external hardware | |
1321 | */ | |
1322 | if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) | |
1323 | return (key_sign(id->key, sigp, lenp, data, datalen)); | |
1324 | /* load the private key from the file */ | |
1325 | if ((prv = load_identity_file(id->filename)) == NULL) | |
1326 | return (-1); | |
1327 | ret = key_sign(prv, sigp, lenp, data, datalen); | |
1328 | key_free(prv); | |
1329 | return (ret); | |
1330 | } | |
1331 | ||
1332 | static int | |
1333 | sign_and_send_pubkey(Authctxt *authctxt, Identity *id) | |
1334 | { | |
1335 | Buffer b; | |
1336 | u_char *blob, *signature; | |
1337 | u_int bloblen, slen; | |
1338 | u_int skip = 0; | |
1339 | int ret = -1; | |
1340 | int have_sig = 1; | |
1341 | ||
1342 | debug3("sign_and_send_pubkey"); | |
1343 | ||
1344 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { | |
1345 | /* we cannot handle this key */ | |
1346 | debug3("sign_and_send_pubkey: cannot handle key"); | |
1347 | return 0; | |
1348 | } | |
1349 | /* data to be signed */ | |
1350 | buffer_init(&b); | |
1351 | if (datafellows & SSH_OLD_SESSIONID) { | |
1352 | buffer_append(&b, session_id2, session_id2_len); | |
1353 | skip = session_id2_len; | |
1354 | } else { | |
1355 | buffer_put_string(&b, session_id2, session_id2_len); | |
1356 | skip = buffer_len(&b); | |
1357 | } | |
1358 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
1359 | buffer_put_cstring(&b, authctxt->server_user); | |
1360 | buffer_put_cstring(&b, | |
1361 | datafellows & SSH_BUG_PKSERVICE ? | |
1362 | "ssh-userauth" : | |
1363 | authctxt->service); | |
1364 | if (datafellows & SSH_BUG_PKAUTH) { | |
1365 | buffer_put_char(&b, have_sig); | |
1366 | } else { | |
1367 | buffer_put_cstring(&b, authctxt->method->name); | |
1368 | buffer_put_char(&b, have_sig); | |
1369 | buffer_put_cstring(&b, key_ssh_name(id->key)); | |
1370 | } | |
1371 | buffer_put_string(&b, blob, bloblen); | |
1372 | ||
1373 | /* generate signature */ | |
1374 | ret = identity_sign(id, &signature, &slen, | |
1375 | buffer_ptr(&b), buffer_len(&b)); | |
1376 | if (ret == -1) { | |
1377 | xfree(blob); | |
1378 | buffer_free(&b); | |
1379 | return 0; | |
1380 | } | |
1381 | #ifdef DEBUG_PK | |
1382 | buffer_dump(&b); | |
1383 | #endif | |
1384 | if (datafellows & SSH_BUG_PKSERVICE) { | |
1385 | buffer_clear(&b); | |
1386 | buffer_append(&b, session_id2, session_id2_len); | |
1387 | skip = session_id2_len; | |
1388 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
1389 | buffer_put_cstring(&b, authctxt->server_user); | |
1390 | buffer_put_cstring(&b, authctxt->service); | |
1391 | buffer_put_cstring(&b, authctxt->method->name); | |
1392 | buffer_put_char(&b, have_sig); | |
1393 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
1394 | buffer_put_cstring(&b, key_ssh_name(id->key)); | |
1395 | buffer_put_string(&b, blob, bloblen); | |
1396 | } | |
1397 | xfree(blob); | |
1398 | ||
1399 | /* append signature */ | |
1400 | buffer_put_string(&b, signature, slen); | |
1401 | xfree(signature); | |
1402 | ||
1403 | /* skip session id and packet type */ | |
1404 | if (buffer_len(&b) < skip + 1) | |
1405 | fatal("userauth_pubkey: internal error"); | |
1406 | buffer_consume(&b, skip + 1); | |
1407 | ||
1408 | /* put remaining data from buffer into packet */ | |
1409 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1410 | packet_put_raw(buffer_ptr(&b), buffer_len(&b)); | |
1411 | buffer_free(&b); | |
1412 | packet_send(); | |
1413 | ||
1414 | return 1; | |
1415 | } | |
1416 | ||
1417 | static int | |
1418 | send_pubkey_test(Authctxt *authctxt, Identity *id) | |
1419 | { | |
1420 | u_char *blob; | |
1421 | u_int bloblen, have_sig = 0; | |
1422 | ||
1423 | debug3("send_pubkey_test"); | |
1424 | ||
1425 | if (key_to_blob(id->key, &blob, &bloblen) == 0) { | |
1426 | /* we cannot handle this key */ | |
1427 | debug3("send_pubkey_test: cannot handle key"); | |
1428 | return 0; | |
1429 | } | |
1430 | /* register callback for USERAUTH_PK_OK message */ | |
1431 | dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); | |
1432 | ||
1433 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1434 | packet_put_cstring(authctxt->server_user); | |
1435 | packet_put_cstring(authctxt->service); | |
1436 | packet_put_cstring(authctxt->method->name); | |
1437 | packet_put_char(have_sig); | |
1438 | if (!(datafellows & SSH_BUG_PKAUTH)) | |
1439 | packet_put_cstring(key_ssh_name(id->key)); | |
1440 | packet_put_string(blob, bloblen); | |
1441 | xfree(blob); | |
1442 | packet_send(); | |
1443 | return 1; | |
1444 | } | |
1445 | ||
1446 | static Key * | |
1447 | load_identity_file(char *filename) | |
1448 | { | |
1449 | Key *private; | |
1450 | char prompt[300], *passphrase; | |
1451 | int perm_ok, quit, i; | |
1452 | struct stat st; | |
1453 | ||
1454 | if (stat(filename, &st) < 0) { | |
1455 | debug3("no such identity: %s", filename); | |
1456 | return NULL; | |
1457 | } | |
1458 | private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); | |
1459 | if (!perm_ok) | |
1460 | return NULL; | |
1461 | if (private == NULL) { | |
1462 | if (options.batch_mode) | |
1463 | return NULL; | |
1464 | snprintf(prompt, sizeof prompt, | |
1465 | "Enter passphrase for key '%.100s': ", filename); | |
1466 | for (i = 0; i < options.number_of_password_prompts; i++) { | |
1467 | passphrase = read_passphrase(prompt, 0); | |
1468 | if (strcmp(passphrase, "") != 0) { | |
1469 | private = key_load_private_type(KEY_UNSPEC, | |
1470 | filename, passphrase, NULL, NULL); | |
1471 | quit = 0; | |
1472 | } else { | |
1473 | debug2("no passphrase given, try next key"); | |
1474 | quit = 1; | |
1475 | } | |
1476 | memset(passphrase, 0, strlen(passphrase)); | |
1477 | xfree(passphrase); | |
1478 | if (private != NULL || quit) | |
1479 | break; | |
1480 | debug2("bad passphrase given, try again..."); | |
1481 | } | |
1482 | } | |
1483 | return private; | |
1484 | } | |
1485 | ||
1486 | /* | |
1487 | * try keys in the following order: | |
1488 | * 1. agent keys that are found in the config file | |
1489 | * 2. other agent keys | |
1490 | * 3. keys that are only listed in the config file | |
1491 | */ | |
1492 | static void | |
1493 | pubkey_prepare(Authctxt *authctxt) | |
1494 | { | |
1495 | Identity *id; | |
1496 | Idlist agent, files, *preferred; | |
1497 | Key *key; | |
1498 | AuthenticationConnection *ac; | |
1499 | char *comment; | |
1500 | int i, found; | |
1501 | ||
1502 | TAILQ_INIT(&agent); /* keys from the agent */ | |
1503 | TAILQ_INIT(&files); /* keys from the config file */ | |
1504 | preferred = &authctxt->keys; | |
1505 | TAILQ_INIT(preferred); /* preferred order of keys */ | |
1506 | ||
1507 | /* list of keys stored in the filesystem */ | |
1508 | for (i = 0; i < options.num_identity_files; i++) { | |
1509 | key = options.identity_keys[i]; | |
1510 | if (key && key->type == KEY_RSA1) | |
1511 | continue; | |
1512 | options.identity_keys[i] = NULL; | |
1513 | id = xcalloc(1, sizeof(*id)); | |
1514 | id->key = key; | |
1515 | id->filename = xstrdup(options.identity_files[i]); | |
1516 | TAILQ_INSERT_TAIL(&files, id, next); | |
1517 | } | |
1518 | /* list of keys supported by the agent */ | |
1519 | if ((ac = ssh_get_authentication_connection())) { | |
1520 | for (key = ssh_get_first_identity(ac, &comment, 2); | |
1521 | key != NULL; | |
1522 | key = ssh_get_next_identity(ac, &comment, 2)) { | |
1523 | found = 0; | |
1524 | TAILQ_FOREACH(id, &files, next) { | |
1525 | /* agent keys from the config file are preferred */ | |
1526 | if (key_equal(key, id->key)) { | |
1527 | key_free(key); | |
1528 | xfree(comment); | |
1529 | TAILQ_REMOVE(&files, id, next); | |
1530 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1531 | id->ac = ac; | |
1532 | found = 1; | |
1533 | break; | |
1534 | } | |
1535 | } | |
1536 | if (!found && !options.identities_only) { | |
1537 | id = xcalloc(1, sizeof(*id)); | |
1538 | id->key = key; | |
1539 | id->filename = comment; | |
1540 | id->ac = ac; | |
1541 | TAILQ_INSERT_TAIL(&agent, id, next); | |
1542 | } | |
1543 | } | |
1544 | /* append remaining agent keys */ | |
1545 | for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { | |
1546 | TAILQ_REMOVE(&agent, id, next); | |
1547 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1548 | } | |
1549 | authctxt->agent = ac; | |
1550 | } | |
1551 | /* append remaining keys from the config file */ | |
1552 | for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { | |
1553 | TAILQ_REMOVE(&files, id, next); | |
1554 | TAILQ_INSERT_TAIL(preferred, id, next); | |
1555 | } | |
1556 | TAILQ_FOREACH(id, preferred, next) { | |
1557 | debug2("key: %s (%p)", id->filename, id->key); | |
1558 | } | |
1559 | } | |
1560 | ||
1561 | static void | |
1562 | pubkey_cleanup(Authctxt *authctxt) | |
1563 | { | |
1564 | Identity *id; | |
1565 | ||
1566 | if (authctxt->agent != NULL) | |
1567 | ssh_close_authentication_connection(authctxt->agent); | |
1568 | for (id = TAILQ_FIRST(&authctxt->keys); id; | |
1569 | id = TAILQ_FIRST(&authctxt->keys)) { | |
1570 | TAILQ_REMOVE(&authctxt->keys, id, next); | |
1571 | if (id->key) | |
1572 | key_free(id->key); | |
1573 | if (id->filename) | |
1574 | xfree(id->filename); | |
1575 | xfree(id); | |
1576 | } | |
1577 | } | |
1578 | ||
1579 | int | |
1580 | userauth_pubkey(Authctxt *authctxt) | |
1581 | { | |
1582 | Identity *id; | |
1583 | int sent = 0; | |
1584 | ||
1585 | while ((id = TAILQ_FIRST(&authctxt->keys))) { | |
1586 | if (id->tried++) | |
1587 | return (0); | |
1588 | /* move key to the end of the queue */ | |
1589 | TAILQ_REMOVE(&authctxt->keys, id, next); | |
1590 | TAILQ_INSERT_TAIL(&authctxt->keys, id, next); | |
1591 | /* | |
1592 | * send a test message if we have the public key. for | |
1593 | * encrypted keys we cannot do this and have to load the | |
1594 | * private key instead | |
1595 | */ | |
1596 | if (id->key && id->key->type != KEY_RSA1) { | |
1597 | debug("Offering public key: %s", id->filename); | |
1598 | sent = send_pubkey_test(authctxt, id); | |
1599 | } else if (id->key == NULL) { | |
1600 | debug("Trying private key: %s", id->filename); | |
1601 | id->key = load_identity_file(id->filename); | |
1602 | if (id->key != NULL) { | |
1603 | id->isprivate = 1; | |
1604 | sent = sign_and_send_pubkey(authctxt, id); | |
1605 | key_free(id->key); | |
1606 | id->key = NULL; | |
1607 | } | |
1608 | } | |
1609 | if (sent) | |
1610 | return (sent); | |
1611 | } | |
1612 | return (0); | |
1613 | } | |
1614 | ||
1615 | /* | |
1616 | * Send userauth request message specifying keyboard-interactive method. | |
1617 | */ | |
1618 | int | |
1619 | userauth_kbdint(Authctxt *authctxt) | |
1620 | { | |
1621 | static int attempt = 0; | |
1622 | ||
1623 | if (attempt++ >= options.number_of_password_prompts) | |
1624 | return 0; | |
1625 | /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ | |
1626 | if (attempt > 1 && !authctxt->info_req_seen) { | |
1627 | debug3("userauth_kbdint: disable: no info_req_seen"); | |
1628 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); | |
1629 | return 0; | |
1630 | } | |
1631 | ||
1632 | debug2("userauth_kbdint"); | |
1633 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1634 | packet_put_cstring(authctxt->server_user); | |
1635 | packet_put_cstring(authctxt->service); | |
1636 | packet_put_cstring(authctxt->method->name); | |
1637 | packet_put_cstring(""); /* lang */ | |
1638 | packet_put_cstring(options.kbd_interactive_devices ? | |
1639 | options.kbd_interactive_devices : ""); | |
1640 | packet_send(); | |
1641 | ||
1642 | dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); | |
1643 | return 1; | |
1644 | } | |
1645 | ||
1646 | /* | |
1647 | * parse INFO_REQUEST, prompt user and send INFO_RESPONSE | |
1648 | */ | |
1649 | void | |
1650 | input_userauth_info_req(int type, u_int32_t seq, void *ctxt) | |
1651 | { | |
1652 | Authctxt *authctxt = ctxt; | |
1653 | char *name, *inst, *lang, *prompt, *response; | |
1654 | u_int num_prompts, i; | |
1655 | int echo = 0; | |
1656 | ||
1657 | debug2("input_userauth_info_req"); | |
1658 | ||
1659 | if (authctxt == NULL) | |
1660 | fatal("input_userauth_info_req: no authentication context"); | |
1661 | ||
1662 | authctxt->info_req_seen = 1; | |
1663 | ||
1664 | name = packet_get_string(NULL); | |
1665 | inst = packet_get_string(NULL); | |
1666 | lang = packet_get_string(NULL); | |
1667 | if (strlen(name) > 0) | |
1668 | logit("%s", name); | |
1669 | if (strlen(inst) > 0) | |
1670 | logit("%s", inst); | |
1671 | xfree(name); | |
1672 | xfree(inst); | |
1673 | xfree(lang); | |
1674 | ||
1675 | num_prompts = packet_get_int(); | |
1676 | /* | |
1677 | * Begin to build info response packet based on prompts requested. | |
1678 | * We commit to providing the correct number of responses, so if | |
1679 | * further on we run into a problem that prevents this, we have to | |
1680 | * be sure and clean this up and send a correct error response. | |
1681 | */ | |
1682 | packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); | |
1683 | packet_put_int(num_prompts); | |
1684 | ||
1685 | debug2("input_userauth_info_req: num_prompts %d", num_prompts); | |
1686 | for (i = 0; i < num_prompts; i++) { | |
1687 | prompt = packet_get_string(NULL); | |
1688 | echo = packet_get_char(); | |
1689 | ||
1690 | response = read_passphrase(prompt, echo ? RP_ECHO : 0); | |
1691 | ||
1692 | packet_put_cstring(response); | |
1693 | memset(response, 0, strlen(response)); | |
1694 | xfree(response); | |
1695 | xfree(prompt); | |
1696 | } | |
1697 | packet_check_eom(); /* done with parsing incoming message. */ | |
1698 | ||
1699 | packet_add_padding(64); | |
1700 | packet_send(); | |
1701 | } | |
1702 | ||
1703 | static int | |
1704 | ssh_keysign(Key *key, u_char **sigp, u_int *lenp, | |
1705 | u_char *data, u_int datalen) | |
1706 | { | |
1707 | Buffer b; | |
1708 | struct stat st; | |
1709 | pid_t pid; | |
1710 | int to[2], from[2], status, version = 2; | |
1711 | ||
1712 | debug2("ssh_keysign called"); | |
1713 | ||
1714 | if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { | |
1715 | error("ssh_keysign: no installed: %s", strerror(errno)); | |
1716 | return -1; | |
1717 | } | |
1718 | if (fflush(stdout) != 0) | |
1719 | error("ssh_keysign: fflush: %s", strerror(errno)); | |
1720 | if (pipe(to) < 0) { | |
1721 | error("ssh_keysign: pipe: %s", strerror(errno)); | |
1722 | return -1; | |
1723 | } | |
1724 | if (pipe(from) < 0) { | |
1725 | error("ssh_keysign: pipe: %s", strerror(errno)); | |
1726 | return -1; | |
1727 | } | |
1728 | if ((pid = fork()) < 0) { | |
1729 | error("ssh_keysign: fork: %s", strerror(errno)); | |
1730 | return -1; | |
1731 | } | |
1732 | if (pid == 0) { | |
1733 | permanently_drop_suid(getuid()); | |
1734 | close(from[0]); | |
1735 | if (dup2(from[1], STDOUT_FILENO) < 0) | |
1736 | fatal("ssh_keysign: dup2: %s", strerror(errno)); | |
1737 | close(to[1]); | |
1738 | if (dup2(to[0], STDIN_FILENO) < 0) | |
1739 | fatal("ssh_keysign: dup2: %s", strerror(errno)); | |
1740 | close(from[1]); | |
1741 | close(to[0]); | |
1742 | execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); | |
1743 | fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, | |
1744 | strerror(errno)); | |
1745 | } | |
1746 | close(from[1]); | |
1747 | close(to[0]); | |
1748 | ||
1749 | buffer_init(&b); | |
1750 | buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ | |
1751 | buffer_put_string(&b, data, datalen); | |
1752 | if (ssh_msg_send(to[1], version, &b) == -1) | |
1753 | fatal("ssh_keysign: couldn't send request"); | |
1754 | ||
1755 | if (ssh_msg_recv(from[0], &b) < 0) { | |
1756 | error("ssh_keysign: no reply"); | |
1757 | buffer_free(&b); | |
1758 | return -1; | |
1759 | } | |
1760 | close(from[0]); | |
1761 | close(to[1]); | |
1762 | ||
1763 | while (waitpid(pid, &status, 0) < 0) | |
1764 | if (errno != EINTR) | |
1765 | break; | |
1766 | ||
1767 | if (buffer_get_char(&b) != version) { | |
1768 | error("ssh_keysign: bad version"); | |
1769 | buffer_free(&b); | |
1770 | return -1; | |
1771 | } | |
1772 | *sigp = buffer_get_string(&b, lenp); | |
1773 | buffer_free(&b); | |
1774 | ||
1775 | return 0; | |
1776 | } | |
1777 | ||
1778 | int | |
1779 | userauth_hostbased(Authctxt *authctxt) | |
1780 | { | |
1781 | Key *private = NULL; | |
1782 | Sensitive *sensitive = authctxt->sensitive; | |
1783 | Buffer b; | |
1784 | u_char *signature, *blob; | |
1785 | char *chost, *pkalg, *p, myname[NI_MAXHOST]; | |
1786 | const char *service; | |
1787 | u_int blen, slen; | |
1788 | int ok, i, len, found = 0; | |
1789 | ||
1790 | /* check for a useful key */ | |
1791 | for (i = 0; i < sensitive->nkeys; i++) { | |
1792 | private = sensitive->keys[i]; | |
1793 | if (private && private->type != KEY_RSA1) { | |
1794 | found = 1; | |
1795 | /* we take and free the key */ | |
1796 | sensitive->keys[i] = NULL; | |
1797 | break; | |
1798 | } | |
1799 | } | |
1800 | if (!found) { | |
1801 | debug("No more client hostkeys for hostbased authentication."); | |
1802 | return 0; | |
1803 | } | |
1804 | if (key_to_blob(private, &blob, &blen) == 0) { | |
1805 | key_free(private); | |
1806 | return 0; | |
1807 | } | |
1808 | /* figure out a name for the client host */ | |
1809 | p = NULL; | |
1810 | if (packet_connection_is_on_socket()) | |
1811 | p = get_local_name(packet_get_connection_in()); | |
1812 | if (p == NULL) { | |
1813 | if (gethostname(myname, sizeof(myname)) == -1) { | |
1814 | verbose("userauth_hostbased: gethostname: %s", | |
1815 | strerror(errno)); | |
1816 | } else | |
1817 | p = xstrdup(myname); | |
1818 | } | |
1819 | if (p == NULL) { | |
1820 | error("userauth_hostbased: cannot get local ipaddr/name"); | |
1821 | key_free(private); | |
1822 | xfree(blob); | |
1823 | return 0; | |
1824 | } | |
1825 | len = strlen(p) + 2; | |
1826 | xasprintf(&chost, "%s.", p); | |
1827 | debug2("userauth_hostbased: chost %s", chost); | |
1828 | xfree(p); | |
1829 | ||
1830 | service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : | |
1831 | authctxt->service; | |
1832 | pkalg = xstrdup(key_ssh_name(private)); | |
1833 | buffer_init(&b); | |
1834 | /* construct data */ | |
1835 | buffer_put_string(&b, session_id2, session_id2_len); | |
1836 | buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); | |
1837 | buffer_put_cstring(&b, authctxt->server_user); | |
1838 | buffer_put_cstring(&b, service); | |
1839 | buffer_put_cstring(&b, authctxt->method->name); | |
1840 | buffer_put_cstring(&b, pkalg); | |
1841 | buffer_put_string(&b, blob, blen); | |
1842 | buffer_put_cstring(&b, chost); | |
1843 | buffer_put_cstring(&b, authctxt->local_user); | |
1844 | #ifdef DEBUG_PK | |
1845 | buffer_dump(&b); | |
1846 | #endif | |
1847 | if (sensitive->external_keysign) | |
1848 | ok = ssh_keysign(private, &signature, &slen, | |
1849 | buffer_ptr(&b), buffer_len(&b)); | |
1850 | else | |
1851 | ok = key_sign(private, &signature, &slen, | |
1852 | buffer_ptr(&b), buffer_len(&b)); | |
1853 | key_free(private); | |
1854 | buffer_free(&b); | |
1855 | if (ok != 0) { | |
1856 | error("key_sign failed"); | |
1857 | xfree(chost); | |
1858 | xfree(pkalg); | |
1859 | xfree(blob); | |
1860 | return 0; | |
1861 | } | |
1862 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1863 | packet_put_cstring(authctxt->server_user); | |
1864 | packet_put_cstring(authctxt->service); | |
1865 | packet_put_cstring(authctxt->method->name); | |
1866 | packet_put_cstring(pkalg); | |
1867 | packet_put_string(blob, blen); | |
1868 | packet_put_cstring(chost); | |
1869 | packet_put_cstring(authctxt->local_user); | |
1870 | packet_put_string(signature, slen); | |
1871 | memset(signature, 's', slen); | |
1872 | xfree(signature); | |
1873 | xfree(chost); | |
1874 | xfree(pkalg); | |
1875 | xfree(blob); | |
1876 | ||
1877 | packet_send(); | |
1878 | return 1; | |
1879 | } | |
1880 | ||
1881 | #ifdef JPAKE | |
1882 | int | |
1883 | userauth_jpake(Authctxt *authctxt) | |
1884 | { | |
1885 | struct jpake_ctx *pctx; | |
1886 | u_char *x1_proof, *x2_proof; | |
1887 | u_int x1_proof_len, x2_proof_len; | |
1888 | static int attempt = 0; /* XXX share with userauth_password's? */ | |
1889 | ||
1890 | if (attempt++ >= options.number_of_password_prompts) | |
1891 | return 0; | |
1892 | if (attempt != 1) | |
1893 | error("Permission denied, please try again."); | |
1894 | ||
1895 | if (authctxt->methoddata != NULL) | |
1896 | fatal("%s: authctxt->methoddata already set (%p)", | |
1897 | __func__, authctxt->methoddata); | |
1898 | ||
1899 | authctxt->methoddata = pctx = jpake_new(); | |
1900 | ||
1901 | /* | |
1902 | * Send request immediately, to get the protocol going while | |
1903 | * we do the initial computations. | |
1904 | */ | |
1905 | packet_start(SSH2_MSG_USERAUTH_REQUEST); | |
1906 | packet_put_cstring(authctxt->server_user); | |
1907 | packet_put_cstring(authctxt->service); | |
1908 | packet_put_cstring(authctxt->method->name); | |
1909 | packet_send(); | |
1910 | packet_write_wait(); | |
1911 | ||
1912 | jpake_step1(pctx->grp, | |
1913 | &pctx->client_id, &pctx->client_id_len, | |
1914 | &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, | |
1915 | &x1_proof, &x1_proof_len, | |
1916 | &x2_proof, &x2_proof_len); | |
1917 | ||
1918 | JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); | |
1919 | ||
1920 | packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); | |
1921 | packet_put_string(pctx->client_id, pctx->client_id_len); | |
1922 | packet_put_bignum2(pctx->g_x1); | |
1923 | packet_put_bignum2(pctx->g_x2); | |
1924 | packet_put_string(x1_proof, x1_proof_len); | |
1925 | packet_put_string(x2_proof, x2_proof_len); | |
1926 | packet_send(); | |
1927 | ||
1928 | bzero(x1_proof, x1_proof_len); | |
1929 | bzero(x2_proof, x2_proof_len); | |
1930 | xfree(x1_proof); | |
1931 | xfree(x2_proof); | |
1932 | ||
1933 | /* Expect step 1 packet from peer */ | |
1934 | dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, | |
1935 | input_userauth_jpake_server_step1); | |
1936 | ||
1937 | return 1; | |
1938 | } | |
1939 | ||
1940 | void | |
1941 | userauth_jpake_cleanup(Authctxt *authctxt) | |
1942 | { | |
1943 | debug3("%s: clean up", __func__); | |
1944 | if (authctxt->methoddata != NULL) { | |
1945 | jpake_free(authctxt->methoddata); | |
1946 | authctxt->methoddata = NULL; | |
1947 | } | |
1948 | } | |
1949 | #endif /* JPAKE */ | |
1950 | ||
1951 | /* find auth method */ | |
1952 | ||
1953 | /* | |
1954 | * given auth method name, if configurable options permit this method fill | |
1955 | * in auth_ident field and return true, otherwise return false. | |
1956 | */ | |
1957 | static int | |
1958 | authmethod_is_enabled(Authmethod *method) | |
1959 | { | |
1960 | if (method == NULL) | |
1961 | return 0; | |
1962 | /* return false if options indicate this method is disabled */ | |
1963 | if (method->enabled == NULL || *method->enabled == 0) | |
1964 | return 0; | |
1965 | /* return false if batch mode is enabled but method needs interactive mode */ | |
1966 | if (method->batch_flag != NULL && *method->batch_flag != 0) | |
1967 | return 0; | |
1968 | return 1; | |
1969 | } | |
1970 | ||
1971 | static Authmethod * | |
1972 | authmethod_lookup(const char *name) | |
1973 | { | |
1974 | Authmethod *method = NULL; | |
1975 | if (name != NULL) | |
1976 | for (method = authmethods; method->name != NULL; method++) | |
1977 | if (strcmp(name, method->name) == 0) | |
1978 | return method; | |
1979 | debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); | |
1980 | return NULL; | |
1981 | } | |
1982 | ||
1983 | /* XXX internal state */ | |
1984 | static Authmethod *current = NULL; | |
1985 | static char *supported = NULL; | |
1986 | static char *preferred = NULL; | |
1987 | ||
1988 | /* | |
1989 | * Given the authentication method list sent by the server, return the | |
1990 | * next method we should try. If the server initially sends a nil list, | |
1991 | * use a built-in default list. | |
1992 | */ | |
1993 | static Authmethod * | |
1994 | authmethod_get(char *authlist) | |
1995 | { | |
1996 | char *name = NULL; | |
1997 | u_int next; | |
1998 | ||
1999 | /* Use a suitable default if we're passed a nil list. */ | |
2000 | if (authlist == NULL || strlen(authlist) == 0) | |
2001 | authlist = options.preferred_authentications; | |
2002 | ||
2003 | if (supported == NULL || strcmp(authlist, supported) != 0) { | |
2004 | debug3("start over, passed a different list %s", authlist); | |
2005 | if (supported != NULL) | |
2006 | xfree(supported); | |
2007 | supported = xstrdup(authlist); | |
2008 | preferred = options.preferred_authentications; | |
2009 | debug3("preferred %s", preferred); | |
2010 | current = NULL; | |
2011 | } else if (current != NULL && authmethod_is_enabled(current)) | |
2012 | return current; | |
2013 | ||
2014 | for (;;) { | |
2015 | if ((name = match_list(preferred, supported, &next)) == NULL) { | |
2016 | debug("No more authentication methods to try."); | |
2017 | current = NULL; | |
2018 | return NULL; | |
2019 | } | |
2020 | preferred += next; | |
2021 | debug3("authmethod_lookup %s", name); | |
2022 | debug3("remaining preferred: %s", preferred); | |
2023 | if ((current = authmethod_lookup(name)) != NULL && | |
2024 | authmethod_is_enabled(current)) { | |
2025 | debug3("authmethod_is_enabled %s", name); | |
2026 | debug("Next authentication method: %s", name); | |
2027 | return current; | |
2028 | } | |
2029 | } | |
2030 | } | |
2031 | ||
2032 | static char * | |
2033 | authmethods_get(void) | |
2034 | { | |
2035 | Authmethod *method = NULL; | |
2036 | Buffer b; | |
2037 | char *list; | |
2038 | ||
2039 | buffer_init(&b); | |
2040 | for (method = authmethods; method->name != NULL; method++) { | |
2041 | if (authmethod_is_enabled(method)) { | |
2042 | if (buffer_len(&b) > 0) | |
2043 | buffer_append(&b, ",", 1); | |
2044 | buffer_append(&b, method->name, strlen(method->name)); | |
2045 | } | |
2046 | } | |
2047 | buffer_append(&b, "\0", 1); | |
2048 | list = xstrdup(buffer_ptr(&b)); | |
2049 | buffer_free(&b); | |
2050 | return list; | |
2051 | } | |
2052 |