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- halex@cvs.openbsd.org 2009/11/22 13:18:00
[openssh-git.git] / sshconnect2.c
blob378526bacd57dfc0ee2ee9104ce525fb121df99b
1 /* $OpenBSD: sshconnect2.c,v 1.175 2009/11/20 00:59:36 dtucker 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 <fcntl.h>
36 #include <netdb.h>
37 #include <pwd.h>
38 #include <signal.h>
39 #include <stdarg.h>
40 #include <stdio.h>
41 #include <string.h>
42 #include <unistd.h>
43 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H)
44 #include <vis.h>
45 #endif
46
47 #include "openbsd-compat/sys-queue.h"
48
49 #include "xmalloc.h"
50 #include "ssh.h"
51 #include "ssh2.h"
52 #include "buffer.h"
53 #include "packet.h"
54 #include "compat.h"
55 #include "cipher.h"
56 #include "key.h"
57 #include "kex.h"
58 #include "myproposal.h"
59 #include "sshconnect.h"
60 #include "authfile.h"
61 #include "dh.h"
62 #include "authfd.h"
63 #include "log.h"
64 #include "readconf.h"
65 #include "misc.h"
66 #include "match.h"
67 #include "dispatch.h"
68 #include "canohost.h"
69 #include "msg.h"
70 #include "pathnames.h"
71 #include "uidswap.h"
72 #include "schnorr.h"
73 #include "jpake.h"
74
75 #ifdef GSSAPI
76 #include "ssh-gss.h"
77 #endif
78
79 /* import */
80 extern char *client_version_string;
81 extern char *server_version_string;
82 extern Options options;
83
84 /*
85 * SSH2 key exchange
86 */
87
88 u_char *session_id2 = NULL;
89 u_int session_id2_len = 0;
90
91 char *xxx_host;
92 struct sockaddr *xxx_hostaddr;
93
94 Kex *xxx_kex = NULL;
95
96 static int
97 verify_host_key_callback(Key *hostkey)
98 {
99 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
100 fatal("Host key verification failed.");
101 return 0;
102 }
103
104 void
105 ssh_kex2(char *host, struct sockaddr *hostaddr)
106 {
107 Kex *kex;
108
109 xxx_host = host;
110 xxx_hostaddr = hostaddr;
111
112 if (options.ciphers == (char *)-1) {
113 logit("No valid ciphers for protocol version 2 given, using defaults.");
114 options.ciphers = NULL;
115 }
116 if (options.ciphers != NULL) {
117 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
118 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
119 }
120 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
121 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
122 myproposal[PROPOSAL_ENC_ALGS_STOC] =
123 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
124 if (options.compression) {
125 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
126 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
127 } else {
128 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
129 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
130 }
131 if (options.macs != NULL) {
132 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
133 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
134 }
135 if (options.hostkeyalgorithms != NULL)
136 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
137 options.hostkeyalgorithms;
138
139 if (options.rekey_limit)
140 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
141
142 /* start key exchange */
143 kex = kex_setup(myproposal);
144 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
145 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
146 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
147 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
148 kex->client_version_string=client_version_string;
149 kex->server_version_string=server_version_string;
150 kex->verify_host_key=&verify_host_key_callback;
151
152 xxx_kex = kex;
153
154 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
155
156 if (options.use_roaming && !kex->roaming) {
157 debug("Roaming not allowed by server");
158 options.use_roaming = 0;
159 }
160
161 session_id2 = kex->session_id;
162 session_id2_len = kex->session_id_len;
163
164 #ifdef DEBUG_KEXDH
165 /* send 1st encrypted/maced/compressed message */
166 packet_start(SSH2_MSG_IGNORE);
167 packet_put_cstring("markus");
168 packet_send();
169 packet_write_wait();
170 #endif
171 }
172
173 /*
174 * Authenticate user
175 */
176
177 typedef struct Authctxt Authctxt;
178 typedef struct Authmethod Authmethod;
179 typedef struct identity Identity;
180 typedef struct idlist Idlist;
181
182 struct identity {
183 TAILQ_ENTRY(identity) next;
184 AuthenticationConnection *ac; /* set if agent supports key */
185 Key *key; /* public/private key */
186 char *filename; /* comment for agent-only keys */
187 int tried;
188 int isprivate; /* key points to the private key */
189 };
190 TAILQ_HEAD(idlist, identity);
191
192 struct Authctxt {
193 const char *server_user;
194 const char *local_user;
195 const char *host;
196 const char *service;
197 Authmethod *method;
198 int success;
199 char *authlist;
200 /* pubkey */
201 Idlist keys;
202 AuthenticationConnection *agent;
203 /* hostbased */
204 Sensitive *sensitive;
205 /* kbd-interactive */
206 int info_req_seen;
207 /* generic */
208 void *methoddata;
209 };
210 struct Authmethod {
211 char *name; /* string to compare against server's list */
212 int (*userauth)(Authctxt *authctxt);
213 void (*cleanup)(Authctxt *authctxt);
214 int *enabled; /* flag in option struct that enables method */
215 int *batch_flag; /* flag in option struct that disables method */
216 };
217
218 void input_userauth_success(int, u_int32_t, void *);
219 void input_userauth_success_unexpected(int, u_int32_t, void *);
220 void input_userauth_failure(int, u_int32_t, void *);
221 void input_userauth_banner(int, u_int32_t, void *);
222 void input_userauth_error(int, u_int32_t, void *);
223 void input_userauth_info_req(int, u_int32_t, void *);
224 void input_userauth_pk_ok(int, u_int32_t, void *);
225 void input_userauth_passwd_changereq(int, u_int32_t, void *);
226 void input_userauth_jpake_server_step1(int, u_int32_t, void *);
227 void input_userauth_jpake_server_step2(int, u_int32_t, void *);
228 void input_userauth_jpake_server_confirm(int, u_int32_t, void *);
229
230 int userauth_none(Authctxt *);
231 int userauth_pubkey(Authctxt *);
232 int userauth_passwd(Authctxt *);
233 int userauth_kbdint(Authctxt *);
234 int userauth_hostbased(Authctxt *);
235 int userauth_jpake(Authctxt *);
236
237 void userauth_jpake_cleanup(Authctxt *);
238
239 #ifdef GSSAPI
240 int userauth_gssapi(Authctxt *authctxt);
241 void input_gssapi_response(int type, u_int32_t, void *);
242 void input_gssapi_token(int type, u_int32_t, void *);
243 void input_gssapi_hash(int type, u_int32_t, void *);
244 void input_gssapi_error(int, u_int32_t, void *);
245 void input_gssapi_errtok(int, u_int32_t, void *);
246 #endif
247
248 void userauth(Authctxt *, char *);
249
250 static int sign_and_send_pubkey(Authctxt *, Identity *);
251 static void pubkey_prepare(Authctxt *);
252 static void pubkey_cleanup(Authctxt *);
253 static Key *load_identity_file(char *);
254
255 static Authmethod *authmethod_get(char *authlist);
256 static Authmethod *authmethod_lookup(const char *name);
257 static char *authmethods_get(void);
258
259 Authmethod authmethods[] = {
260 #ifdef GSSAPI
261 {"gssapi-with-mic",
262 userauth_gssapi,
263 NULL,
264 &options.gss_authentication,
265 NULL},
266 #endif
267 {"hostbased",
268 userauth_hostbased,
269 NULL,
270 &options.hostbased_authentication,
271 NULL},
272 {"publickey",
273 userauth_pubkey,
274 NULL,
275 &options.pubkey_authentication,
276 NULL},
277 #ifdef JPAKE
278 {"jpake-01@openssh.com",
279 userauth_jpake,
280 userauth_jpake_cleanup,
281 &options.zero_knowledge_password_authentication,
282 &options.batch_mode},
283 #endif
284 {"keyboard-interactive",
285 userauth_kbdint,
286 NULL,
287 &options.kbd_interactive_authentication,
288 &options.batch_mode},
289 {"password",
290 userauth_passwd,
291 NULL,
292 &options.password_authentication,
293 &options.batch_mode},
294 {"none",
295 userauth_none,
296 NULL,
297 NULL,
298 NULL},
299 {NULL, NULL, NULL, NULL, NULL}
300 };
301
302 void
303 ssh_userauth2(const char *local_user, const char *server_user, char *host,
304 Sensitive *sensitive)
305 {
306 Authctxt authctxt;
307 int type;
308
309 if (options.challenge_response_authentication)
310 options.kbd_interactive_authentication = 1;
311
312 packet_start(SSH2_MSG_SERVICE_REQUEST);
313 packet_put_cstring("ssh-userauth");
314 packet_send();
315 debug("SSH2_MSG_SERVICE_REQUEST sent");
316 packet_write_wait();
317 type = packet_read();
318 if (type != SSH2_MSG_SERVICE_ACCEPT)
319 fatal("Server denied authentication request: %d", type);
320 if (packet_remaining() > 0) {
321 char *reply = packet_get_string(NULL);
322 debug2("service_accept: %s", reply);
323 xfree(reply);
324 } else {
325 debug2("buggy server: service_accept w/o service");
326 }
327 packet_check_eom();
328 debug("SSH2_MSG_SERVICE_ACCEPT received");
329
330 if (options.preferred_authentications == NULL)
331 options.preferred_authentications = authmethods_get();
332
333 /* setup authentication context */
334 memset(&authctxt, 0, sizeof(authctxt));
335 pubkey_prepare(&authctxt);
336 authctxt.server_user = server_user;
337 authctxt.local_user = local_user;
338 authctxt.host = host;
339 authctxt.service = "ssh-connection"; /* service name */
340 authctxt.success = 0;
341 authctxt.method = authmethod_lookup("none");
342 authctxt.authlist = NULL;
343 authctxt.methoddata = NULL;
344 authctxt.sensitive = sensitive;
345 authctxt.info_req_seen = 0;
346 if (authctxt.method == NULL)
347 fatal("ssh_userauth2: internal error: cannot send userauth none request");
348
349 /* initial userauth request */
350 userauth_none(&authctxt);
351
352 dispatch_init(&input_userauth_error);
353 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
354 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
355 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
356 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
357
358 pubkey_cleanup(&authctxt);
359 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
360
361 debug("Authentication succeeded (%s).", authctxt.method->name);
362 }
363
364 void
365 userauth(Authctxt *authctxt, char *authlist)
366 {
367 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
368 authctxt->method->cleanup(authctxt);
369
370 if (authctxt->methoddata) {
371 xfree(authctxt->methoddata);
372 authctxt->methoddata = NULL;
373 }
374 if (authlist == NULL) {
375 authlist = authctxt->authlist;
376 } else {
377 if (authctxt->authlist)
378 xfree(authctxt->authlist);
379 authctxt->authlist = authlist;
380 }
381 for (;;) {
382 Authmethod *method = authmethod_get(authlist);
383 if (method == NULL)
384 fatal("Permission denied (%s).", authlist);
385 authctxt->method = method;
386
387 /* reset the per method handler */
388 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
389 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
390
391 /* and try new method */
392 if (method->userauth(authctxt) != 0) {
393 debug2("we sent a %s packet, wait for reply", method->name);
394 break;
395 } else {
396 debug2("we did not send a packet, disable method");
397 method->enabled = NULL;
398 }
399 }
400 }
401
402 /* ARGSUSED */
403 void
404 input_userauth_error(int type, u_int32_t seq, void *ctxt)
405 {
406 fatal("input_userauth_error: bad message during authentication: "
407 "type %d", type);
408 }
409
410 /* ARGSUSED */
411 void
412 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
413 {
414 char *msg, *raw, *lang;
415 u_int len;
416
417 debug3("input_userauth_banner");
418 raw = packet_get_string(&len);
419 lang = packet_get_string(NULL);
420 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
421 if (len > 65536)
422 len = 65536;
423 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
424 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL);
425 fprintf(stderr, "%s", msg);
426 xfree(msg);
427 }
428 xfree(raw);
429 xfree(lang);
430 }
431
432 /* ARGSUSED */
433 void
434 input_userauth_success(int type, u_int32_t seq, void *ctxt)
435 {
436 Authctxt *authctxt = ctxt;
437
438 if (authctxt == NULL)
439 fatal("input_userauth_success: no authentication context");
440 if (authctxt->authlist) {
441 xfree(authctxt->authlist);
442 authctxt->authlist = NULL;
443 }
444 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
445 authctxt->method->cleanup(authctxt);
446 if (authctxt->methoddata) {
447 xfree(authctxt->methoddata);
448 authctxt->methoddata = NULL;
449 }
450 authctxt->success = 1; /* break out */
451 }
452
453 void
454 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt)
455 {
456 Authctxt *authctxt = ctxt;
457
458 if (authctxt == NULL)
459 fatal("%s: no authentication context", __func__);
460
461 fatal("Unexpected authentication success during %s.",
462 authctxt->method->name);
463 }
464
465 /* ARGSUSED */
466 void
467 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
468 {
469 Authctxt *authctxt = ctxt;
470 char *authlist = NULL;
471 int partial;
472
473 if (authctxt == NULL)
474 fatal("input_userauth_failure: no authentication context");
475
476 authlist = packet_get_string(NULL);
477 partial = packet_get_char();
478 packet_check_eom();
479
480 if (partial != 0)
481 logit("Authenticated with partial success.");
482 debug("Authentications that can continue: %s", authlist);
483
484 userauth(authctxt, authlist);
485 }
486
487 /* ARGSUSED */
488 void
489 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
490 {
491 Authctxt *authctxt = ctxt;
492 Key *key = NULL;
493 Identity *id = NULL;
494 Buffer b;
495 int pktype, sent = 0;
496 u_int alen, blen;
497 char *pkalg, *fp;
498 u_char *pkblob;
499
500 if (authctxt == NULL)
501 fatal("input_userauth_pk_ok: no authentication context");
502 if (datafellows & SSH_BUG_PKOK) {
503 /* this is similar to SSH_BUG_PKAUTH */
504 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
505 pkblob = packet_get_string(&blen);
506 buffer_init(&b);
507 buffer_append(&b, pkblob, blen);
508 pkalg = buffer_get_string(&b, &alen);
509 buffer_free(&b);
510 } else {
511 pkalg = packet_get_string(&alen);
512 pkblob = packet_get_string(&blen);
513 }
514 packet_check_eom();
515
516 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
517
518 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
519 debug("unknown pkalg %s", pkalg);
520 goto done;
521 }
522 if ((key = key_from_blob(pkblob, blen)) == NULL) {
523 debug("no key from blob. pkalg %s", pkalg);
524 goto done;
525 }
526 if (key->type != pktype) {
527 error("input_userauth_pk_ok: type mismatch "
528 "for decoded key (received %d, expected %d)",
529 key->type, pktype);
530 goto done;
531 }
532 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
533 debug2("input_userauth_pk_ok: fp %s", fp);
534 xfree(fp);
535
536 /*
537 * search keys in the reverse order, because last candidate has been
538 * moved to the end of the queue. this also avoids confusion by
539 * duplicate keys
540 */
541 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
542 if (key_equal(key, id->key)) {
543 sent = sign_and_send_pubkey(authctxt, id);
544 break;
545 }
546 }
547 done:
548 if (key != NULL)
549 key_free(key);
550 xfree(pkalg);
551 xfree(pkblob);
552
553 /* try another method if we did not send a packet */
554 if (sent == 0)
555 userauth(authctxt, NULL);
556 }
557
558 #ifdef GSSAPI
559 int
560 userauth_gssapi(Authctxt *authctxt)
561 {
562 Gssctxt *gssctxt = NULL;
563 static gss_OID_set gss_supported = NULL;
564 static u_int mech = 0;
565 OM_uint32 min;
566 int ok = 0;
567
568 /* Try one GSSAPI method at a time, rather than sending them all at
569 * once. */
570
571 if (gss_supported == NULL)
572 gss_indicate_mechs(&min, &gss_supported);
573
574 /* Check to see if the mechanism is usable before we offer it */
575 while (mech < gss_supported->count && !ok) {
576 /* My DER encoding requires length<128 */
577 if (gss_supported->elements[mech].length < 128 &&
578 ssh_gssapi_check_mechanism(&gssctxt,
579 &gss_supported->elements[mech], authctxt->host)) {
580 ok = 1; /* Mechanism works */
581 } else {
582 mech++;
583 }
584 }
585
586 if (!ok)
587 return 0;
588
589 authctxt->methoddata=(void *)gssctxt;
590
591 packet_start(SSH2_MSG_USERAUTH_REQUEST);
592 packet_put_cstring(authctxt->server_user);
593 packet_put_cstring(authctxt->service);
594 packet_put_cstring(authctxt->method->name);
595
596 packet_put_int(1);
597
598 packet_put_int((gss_supported->elements[mech].length) + 2);
599 packet_put_char(SSH_GSS_OIDTYPE);
600 packet_put_char(gss_supported->elements[mech].length);
601 packet_put_raw(gss_supported->elements[mech].elements,
602 gss_supported->elements[mech].length);
603
604 packet_send();
605
606 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
607 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
608 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
609 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
610
611 mech++; /* Move along to next candidate */
612
613 return 1;
614 }
615
616 static OM_uint32
617 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
618 {
619 Authctxt *authctxt = ctxt;
620 Gssctxt *gssctxt = authctxt->methoddata;
621 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
622 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
623 gss_buffer_desc gssbuf;
624 OM_uint32 status, ms, flags;
625 Buffer b;
626
627 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
628 recv_tok, &send_tok, &flags);
629
630 if (send_tok.length > 0) {
631 if (GSS_ERROR(status))
632 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
633 else
634 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
635
636 packet_put_string(send_tok.value, send_tok.length);
637 packet_send();
638 gss_release_buffer(&ms, &send_tok);
639 }
640
641 if (status == GSS_S_COMPLETE) {
642 /* send either complete or MIC, depending on mechanism */
643 if (!(flags & GSS_C_INTEG_FLAG)) {
644 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
645 packet_send();
646 } else {
647 ssh_gssapi_buildmic(&b, authctxt->server_user,
648 authctxt->service, "gssapi-with-mic");
649
650 gssbuf.value = buffer_ptr(&b);
651 gssbuf.length = buffer_len(&b);
652
653 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
654
655 if (!GSS_ERROR(status)) {
656 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
657 packet_put_string(mic.value, mic.length);
658
659 packet_send();
660 }
661
662 buffer_free(&b);
663 gss_release_buffer(&ms, &mic);
664 }
665 }
666
667 return status;
668 }
669
670 /* ARGSUSED */
671 void
672 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
673 {
674 Authctxt *authctxt = ctxt;
675 Gssctxt *gssctxt;
676 int oidlen;
677 char *oidv;
678
679 if (authctxt == NULL)
680 fatal("input_gssapi_response: no authentication context");
681 gssctxt = authctxt->methoddata;
682
683 /* Setup our OID */
684 oidv = packet_get_string(&oidlen);
685
686 if (oidlen <= 2 ||
687 oidv[0] != SSH_GSS_OIDTYPE ||
688 oidv[1] != oidlen - 2) {
689 xfree(oidv);
690 debug("Badly encoded mechanism OID received");
691 userauth(authctxt, NULL);
692 return;
693 }
694
695 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
696 fatal("Server returned different OID than expected");
697
698 packet_check_eom();
699
700 xfree(oidv);
701
702 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
703 /* Start again with next method on list */
704 debug("Trying to start again");
705 userauth(authctxt, NULL);
706 return;
707 }
708 }
709
710 /* ARGSUSED */
711 void
712 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
713 {
714 Authctxt *authctxt = ctxt;
715 gss_buffer_desc recv_tok;
716 OM_uint32 status;
717 u_int slen;
718
719 if (authctxt == NULL)
720 fatal("input_gssapi_response: no authentication context");
721
722 recv_tok.value = packet_get_string(&slen);
723 recv_tok.length = slen; /* safe typecast */
724
725 packet_check_eom();
726
727 status = process_gssapi_token(ctxt, &recv_tok);
728
729 xfree(recv_tok.value);
730
731 if (GSS_ERROR(status)) {
732 /* Start again with the next method in the list */
733 userauth(authctxt, NULL);
734 return;
735 }
736 }
737
738 /* ARGSUSED */
739 void
740 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
741 {
742 Authctxt *authctxt = ctxt;
743 Gssctxt *gssctxt;
744 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
745 gss_buffer_desc recv_tok;
746 OM_uint32 status, ms;
747 u_int len;
748
749 if (authctxt == NULL)
750 fatal("input_gssapi_response: no authentication context");
751 gssctxt = authctxt->methoddata;
752
753 recv_tok.value = packet_get_string(&len);
754 recv_tok.length = len;
755
756 packet_check_eom();
757
758 /* Stick it into GSSAPI and see what it says */
759 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
760 &recv_tok, &send_tok, NULL);
761
762 xfree(recv_tok.value);
763 gss_release_buffer(&ms, &send_tok);
764
765 /* Server will be returning a failed packet after this one */
766 }
767
768 /* ARGSUSED */
769 void
770 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
771 {
772 OM_uint32 maj, min;
773 char *msg;
774 char *lang;
775
776 maj=packet_get_int();
777 min=packet_get_int();
778 msg=packet_get_string(NULL);
779 lang=packet_get_string(NULL);
780
781 packet_check_eom();
782
783 debug("Server GSSAPI Error:\n%s", msg);
784 xfree(msg);
785 xfree(lang);
786 }
787 #endif /* GSSAPI */
788
789 int
790 userauth_none(Authctxt *authctxt)
791 {
792 /* initial userauth request */
793 packet_start(SSH2_MSG_USERAUTH_REQUEST);
794 packet_put_cstring(authctxt->server_user);
795 packet_put_cstring(authctxt->service);
796 packet_put_cstring(authctxt->method->name);
797 packet_send();
798 return 1;
799 }
800
801 int
802 userauth_passwd(Authctxt *authctxt)
803 {
804 static int attempt = 0;
805 char prompt[150];
806 char *password;
807 const char *host = options.host_key_alias ? options.host_key_alias :
808 authctxt->host;
809
810 if (attempt++ >= options.number_of_password_prompts)
811 return 0;
812
813 if (attempt != 1)
814 error("Permission denied, please try again.");
815
816 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
817 authctxt->server_user, host);
818 password = read_passphrase(prompt, 0);
819 packet_start(SSH2_MSG_USERAUTH_REQUEST);
820 packet_put_cstring(authctxt->server_user);
821 packet_put_cstring(authctxt->service);
822 packet_put_cstring(authctxt->method->name);
823 packet_put_char(0);
824 packet_put_cstring(password);
825 memset(password, 0, strlen(password));
826 xfree(password);
827 packet_add_padding(64);
828 packet_send();
829
830 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
831 &input_userauth_passwd_changereq);
832
833 return 1;
834 }
835
836 /*
837 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
838 */
839 /* ARGSUSED */
840 void
841 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
842 {
843 Authctxt *authctxt = ctxt;
844 char *info, *lang, *password = NULL, *retype = NULL;
845 char prompt[150];
846 const char *host = options.host_key_alias ? options.host_key_alias :
847 authctxt->host;
848
849 debug2("input_userauth_passwd_changereq");
850
851 if (authctxt == NULL)
852 fatal("input_userauth_passwd_changereq: "
853 "no authentication context");
854
855 info = packet_get_string(NULL);
856 lang = packet_get_string(NULL);
857 if (strlen(info) > 0)
858 logit("%s", info);
859 xfree(info);
860 xfree(lang);
861 packet_start(SSH2_MSG_USERAUTH_REQUEST);
862 packet_put_cstring(authctxt->server_user);
863 packet_put_cstring(authctxt->service);
864 packet_put_cstring(authctxt->method->name);
865 packet_put_char(1); /* additional info */
866 snprintf(prompt, sizeof(prompt),
867 "Enter %.30s@%.128s's old password: ",
868 authctxt->server_user, host);
869 password = read_passphrase(prompt, 0);
870 packet_put_cstring(password);
871 memset(password, 0, strlen(password));
872 xfree(password);
873 password = NULL;
874 while (password == NULL) {
875 snprintf(prompt, sizeof(prompt),
876 "Enter %.30s@%.128s's new password: ",
877 authctxt->server_user, host);
878 password = read_passphrase(prompt, RP_ALLOW_EOF);
879 if (password == NULL) {
880 /* bail out */
881 return;
882 }
883 snprintf(prompt, sizeof(prompt),
884 "Retype %.30s@%.128s's new password: ",
885 authctxt->server_user, host);
886 retype = read_passphrase(prompt, 0);
887 if (strcmp(password, retype) != 0) {
888 memset(password, 0, strlen(password));
889 xfree(password);
890 logit("Mismatch; try again, EOF to quit.");
891 password = NULL;
892 }
893 memset(retype, 0, strlen(retype));
894 xfree(retype);
895 }
896 packet_put_cstring(password);
897 memset(password, 0, strlen(password));
898 xfree(password);
899 packet_add_padding(64);
900 packet_send();
901
902 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
903 &input_userauth_passwd_changereq);
904 }
905
906 #ifdef JPAKE
907 static char *
908 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
909 {
910 /* OpenBSD crypt(3) handles all of these */
911 if (strcmp(crypt_scheme, "crypt") == 0 ||
912 strcmp(crypt_scheme, "bcrypt") == 0 ||
913 strcmp(crypt_scheme, "md5crypt") == 0 ||
914 strcmp(crypt_scheme, "crypt-extended") == 0)
915 return xstrdup(crypt(password, salt));
916 error("%s: unsupported password encryption scheme \"%.100s\"",
917 __func__, crypt_scheme);
918 return NULL;
919 }
920
921 static BIGNUM *
922 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
923 const char *salt)
924 {
925 char prompt[256], *password, *crypted;
926 u_char *secret;
927 u_int secret_len;
928 BIGNUM *ret;
929
930 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
931 authctxt->server_user, authctxt->host);
932 password = read_passphrase(prompt, 0);
933
934 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
935 logit("Disabling %s authentication", authctxt->method->name);
936 authctxt->method->enabled = NULL;
937 /* Continue with an empty password to fail gracefully */
938 crypted = xstrdup("");
939 }
940
941 #ifdef JPAKE_DEBUG
942 debug3("%s: salt = %s", __func__, salt);
943 debug3("%s: scheme = %s", __func__, crypt_scheme);
944 debug3("%s: crypted = %s", __func__, crypted);
945 #endif
946
947 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(),
948 &secret, &secret_len) != 0)
949 fatal("%s: hash_buffer", __func__);
950
951 bzero(password, strlen(password));
952 bzero(crypted, strlen(crypted));
953 xfree(password);
954 xfree(crypted);
955
956 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
957 fatal("%s: BN_bin2bn (secret)", __func__);
958 bzero(secret, secret_len);
959 xfree(secret);
960
961 return ret;
962 }
963
964 /* ARGSUSED */
965 void
966 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
967 {
968 Authctxt *authctxt = ctxt;
969 struct jpake_ctx *pctx = authctxt->methoddata;
970 u_char *x3_proof, *x4_proof, *x2_s_proof;
971 u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
972 char *crypt_scheme, *salt;
973
974 /* Disable this message */
975 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
976
977 if ((pctx->g_x3 = BN_new()) == NULL ||
978 (pctx->g_x4 = BN_new()) == NULL)
979 fatal("%s: BN_new", __func__);
980
981 /* Fetch step 1 values */
982 crypt_scheme = packet_get_string(NULL);
983 salt = packet_get_string(NULL);
984 pctx->server_id = packet_get_string(&pctx->server_id_len);
985 packet_get_bignum2(pctx->g_x3);
986 packet_get_bignum2(pctx->g_x4);
987 x3_proof = packet_get_string(&x3_proof_len);
988 x4_proof = packet_get_string(&x4_proof_len);
989 packet_check_eom();
990
991 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
992
993 /* Obtain password and derive secret */
994 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
995 bzero(crypt_scheme, strlen(crypt_scheme));
996 bzero(salt, strlen(salt));
997 xfree(crypt_scheme);
998 xfree(salt);
999 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
1000
1001 /* Calculate step 2 values */
1002 jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
1003 pctx->g_x3, pctx->g_x4, pctx->x2,
1004 pctx->server_id, pctx->server_id_len,
1005 pctx->client_id, pctx->client_id_len,
1006 x3_proof, x3_proof_len,
1007 x4_proof, x4_proof_len,
1008 &pctx->a,
1009 &x2_s_proof, &x2_s_proof_len);
1010
1011 bzero(x3_proof, x3_proof_len);
1012 bzero(x4_proof, x4_proof_len);
1013 xfree(x3_proof);
1014 xfree(x4_proof);
1015
1016 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
1017
1018 /* Send values for step 2 */
1019 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
1020 packet_put_bignum2(pctx->a);
1021 packet_put_string(x2_s_proof, x2_s_proof_len);
1022 packet_send();
1023
1024 bzero(x2_s_proof, x2_s_proof_len);
1025 xfree(x2_s_proof);
1026
1027 /* Expect step 2 packet from peer */
1028 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1029 input_userauth_jpake_server_step2);
1030 }
1031
1032 /* ARGSUSED */
1033 void
1034 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1035 {
1036 Authctxt *authctxt = ctxt;
1037 struct jpake_ctx *pctx = authctxt->methoddata;
1038 u_char *x4_s_proof;
1039 u_int x4_s_proof_len;
1040
1041 /* Disable this message */
1042 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1043
1044 if ((pctx->b = BN_new()) == NULL)
1045 fatal("%s: BN_new", __func__);
1046
1047 /* Fetch step 2 values */
1048 packet_get_bignum2(pctx->b);
1049 x4_s_proof = packet_get_string(&x4_s_proof_len);
1050 packet_check_eom();
1051
1052 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1053
1054 /* Derive shared key and calculate confirmation hash */
1055 jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1056 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1057 pctx->client_id, pctx->client_id_len,
1058 pctx->server_id, pctx->server_id_len,
1059 session_id2, session_id2_len,
1060 x4_s_proof, x4_s_proof_len,
1061 &pctx->k,
1062 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1063
1064 bzero(x4_s_proof, x4_s_proof_len);
1065 xfree(x4_s_proof);
1066
1067 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1068
1069 /* Send key confirmation proof */
1070 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1071 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1072 packet_send();
1073
1074 /* Expect confirmation from peer */
1075 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1076 input_userauth_jpake_server_confirm);
1077 }
1078
1079 /* ARGSUSED */
1080 void
1081 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1082 {
1083 Authctxt *authctxt = ctxt;
1084 struct jpake_ctx *pctx = authctxt->methoddata;
1085
1086 /* Disable this message */
1087 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1088
1089 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1090 packet_check_eom();
1091
1092 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1093
1094 /* Verify expected confirmation hash */
1095 if (jpake_check_confirm(pctx->k,
1096 pctx->server_id, pctx->server_id_len,
1097 session_id2, session_id2_len,
1098 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1099 debug("%s: %s success", __func__, authctxt->method->name);
1100 else {
1101 debug("%s: confirmation mismatch", __func__);
1102 /* XXX stash this so if auth succeeds then we can warn/kill */
1103 }
1104
1105 userauth_jpake_cleanup(authctxt);
1106 }
1107 #endif /* JPAKE */
1108
1109 static int
1110 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1111 u_char *data, u_int datalen)
1112 {
1113 Key *prv;
1114 int ret;
1115
1116 /* the agent supports this key */
1117 if (id->ac)
1118 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1119 data, datalen));
1120 /*
1121 * we have already loaded the private key or
1122 * the private key is stored in external hardware
1123 */
1124 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1125 return (key_sign(id->key, sigp, lenp, data, datalen));
1126 /* load the private key from the file */
1127 if ((prv = load_identity_file(id->filename)) == NULL)
1128 return (-1);
1129 ret = key_sign(prv, sigp, lenp, data, datalen);
1130 key_free(prv);
1131 return (ret);
1132 }
1133
1134 static int
1135 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1136 {
1137 Buffer b;
1138 u_char *blob, *signature;
1139 u_int bloblen, slen;
1140 u_int skip = 0;
1141 int ret = -1;
1142 int have_sig = 1;
1143
1144 debug3("sign_and_send_pubkey");
1145
1146 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1147 /* we cannot handle this key */
1148 debug3("sign_and_send_pubkey: cannot handle key");
1149 return 0;
1150 }
1151 /* data to be signed */
1152 buffer_init(&b);
1153 if (datafellows & SSH_OLD_SESSIONID) {
1154 buffer_append(&b, session_id2, session_id2_len);
1155 skip = session_id2_len;
1156 } else {
1157 buffer_put_string(&b, session_id2, session_id2_len);
1158 skip = buffer_len(&b);
1159 }
1160 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1161 buffer_put_cstring(&b, authctxt->server_user);
1162 buffer_put_cstring(&b,
1163 datafellows & SSH_BUG_PKSERVICE ?
1164 "ssh-userauth" :
1165 authctxt->service);
1166 if (datafellows & SSH_BUG_PKAUTH) {
1167 buffer_put_char(&b, have_sig);
1168 } else {
1169 buffer_put_cstring(&b, authctxt->method->name);
1170 buffer_put_char(&b, have_sig);
1171 buffer_put_cstring(&b, key_ssh_name(id->key));
1172 }
1173 buffer_put_string(&b, blob, bloblen);
1174
1175 /* generate signature */
1176 ret = identity_sign(id, &signature, &slen,
1177 buffer_ptr(&b), buffer_len(&b));
1178 if (ret == -1) {
1179 xfree(blob);
1180 buffer_free(&b);
1181 return 0;
1182 }
1183 #ifdef DEBUG_PK
1184 buffer_dump(&b);
1185 #endif
1186 if (datafellows & SSH_BUG_PKSERVICE) {
1187 buffer_clear(&b);
1188 buffer_append(&b, session_id2, session_id2_len);
1189 skip = session_id2_len;
1190 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1191 buffer_put_cstring(&b, authctxt->server_user);
1192 buffer_put_cstring(&b, authctxt->service);
1193 buffer_put_cstring(&b, authctxt->method->name);
1194 buffer_put_char(&b, have_sig);
1195 if (!(datafellows & SSH_BUG_PKAUTH))
1196 buffer_put_cstring(&b, key_ssh_name(id->key));
1197 buffer_put_string(&b, blob, bloblen);
1198 }
1199 xfree(blob);
1200
1201 /* append signature */
1202 buffer_put_string(&b, signature, slen);
1203 xfree(signature);
1204
1205 /* skip session id and packet type */
1206 if (buffer_len(&b) < skip + 1)
1207 fatal("userauth_pubkey: internal error");
1208 buffer_consume(&b, skip + 1);
1209
1210 /* put remaining data from buffer into packet */
1211 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1212 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1213 buffer_free(&b);
1214 packet_send();
1215
1216 return 1;
1217 }
1218
1219 static int
1220 send_pubkey_test(Authctxt *authctxt, Identity *id)
1221 {
1222 u_char *blob;
1223 u_int bloblen, have_sig = 0;
1224
1225 debug3("send_pubkey_test");
1226
1227 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1228 /* we cannot handle this key */
1229 debug3("send_pubkey_test: cannot handle key");
1230 return 0;
1231 }
1232 /* register callback for USERAUTH_PK_OK message */
1233 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1234
1235 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1236 packet_put_cstring(authctxt->server_user);
1237 packet_put_cstring(authctxt->service);
1238 packet_put_cstring(authctxt->method->name);
1239 packet_put_char(have_sig);
1240 if (!(datafellows & SSH_BUG_PKAUTH))
1241 packet_put_cstring(key_ssh_name(id->key));
1242 packet_put_string(blob, bloblen);
1243 xfree(blob);
1244 packet_send();
1245 return 1;
1246 }
1247
1248 static Key *
1249 load_identity_file(char *filename)
1250 {
1251 Key *private;
1252 char prompt[300], *passphrase;
1253 int perm_ok, quit, i;
1254 struct stat st;
1255
1256 if (stat(filename, &st) < 0) {
1257 debug3("no such identity: %s", filename);
1258 return NULL;
1259 }
1260 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1261 if (!perm_ok)
1262 return NULL;
1263 if (private == NULL) {
1264 if (options.batch_mode)
1265 return NULL;
1266 snprintf(prompt, sizeof prompt,
1267 "Enter passphrase for key '%.100s': ", filename);
1268 for (i = 0; i < options.number_of_password_prompts; i++) {
1269 passphrase = read_passphrase(prompt, 0);
1270 if (strcmp(passphrase, "") != 0) {
1271 private = key_load_private_type(KEY_UNSPEC,
1272 filename, passphrase, NULL, NULL);
1273 quit = 0;
1274 } else {
1275 debug2("no passphrase given, try next key");
1276 quit = 1;
1277 }
1278 memset(passphrase, 0, strlen(passphrase));
1279 xfree(passphrase);
1280 if (private != NULL || quit)
1281 break;
1282 debug2("bad passphrase given, try again...");
1283 }
1284 }
1285 return private;
1286 }
1287
1288 /*
1289 * try keys in the following order:
1290 * 1. agent keys that are found in the config file
1291 * 2. other agent keys
1292 * 3. keys that are only listed in the config file
1293 */
1294 static void
1295 pubkey_prepare(Authctxt *authctxt)
1296 {
1297 Identity *id;
1298 Idlist agent, files, *preferred;
1299 Key *key;
1300 AuthenticationConnection *ac;
1301 char *comment;
1302 int i, found;
1303
1304 TAILQ_INIT(&agent); /* keys from the agent */
1305 TAILQ_INIT(&files); /* keys from the config file */
1306 preferred = &authctxt->keys;
1307 TAILQ_INIT(preferred); /* preferred order of keys */
1308
1309 /* list of keys stored in the filesystem */
1310 for (i = 0; i < options.num_identity_files; i++) {
1311 key = options.identity_keys[i];
1312 if (key && key->type == KEY_RSA1)
1313 continue;
1314 options.identity_keys[i] = NULL;
1315 id = xcalloc(1, sizeof(*id));
1316 id->key = key;
1317 id->filename = xstrdup(options.identity_files[i]);
1318 TAILQ_INSERT_TAIL(&files, id, next);
1319 }
1320 /* list of keys supported by the agent */
1321 if ((ac = ssh_get_authentication_connection())) {
1322 for (key = ssh_get_first_identity(ac, &comment, 2);
1323 key != NULL;
1324 key = ssh_get_next_identity(ac, &comment, 2)) {
1325 found = 0;
1326 TAILQ_FOREACH(id, &files, next) {
1327 /* agent keys from the config file are preferred */
1328 if (key_equal(key, id->key)) {
1329 key_free(key);
1330 xfree(comment);
1331 TAILQ_REMOVE(&files, id, next);
1332 TAILQ_INSERT_TAIL(preferred, id, next);
1333 id->ac = ac;
1334 found = 1;
1335 break;
1336 }
1337 }
1338 if (!found && !options.identities_only) {
1339 id = xcalloc(1, sizeof(*id));
1340 id->key = key;
1341 id->filename = comment;
1342 id->ac = ac;
1343 TAILQ_INSERT_TAIL(&agent, id, next);
1344 }
1345 }
1346 /* append remaining agent keys */
1347 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1348 TAILQ_REMOVE(&agent, id, next);
1349 TAILQ_INSERT_TAIL(preferred, id, next);
1350 }
1351 authctxt->agent = ac;
1352 }
1353 /* append remaining keys from the config file */
1354 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1355 TAILQ_REMOVE(&files, id, next);
1356 TAILQ_INSERT_TAIL(preferred, id, next);
1357 }
1358 TAILQ_FOREACH(id, preferred, next) {
1359 debug2("key: %s (%p)", id->filename, id->key);
1360 }
1361 }
1362
1363 static void
1364 pubkey_cleanup(Authctxt *authctxt)
1365 {
1366 Identity *id;
1367
1368 if (authctxt->agent != NULL)
1369 ssh_close_authentication_connection(authctxt->agent);
1370 for (id = TAILQ_FIRST(&authctxt->keys); id;
1371 id = TAILQ_FIRST(&authctxt->keys)) {
1372 TAILQ_REMOVE(&authctxt->keys, id, next);
1373 if (id->key)
1374 key_free(id->key);
1375 if (id->filename)
1376 xfree(id->filename);
1377 xfree(id);
1378 }
1379 }
1380
1381 int
1382 userauth_pubkey(Authctxt *authctxt)
1383 {
1384 Identity *id;
1385 int sent = 0;
1386
1387 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1388 if (id->tried++)
1389 return (0);
1390 /* move key to the end of the queue */
1391 TAILQ_REMOVE(&authctxt->keys, id, next);
1392 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1393 /*
1394 * send a test message if we have the public key. for
1395 * encrypted keys we cannot do this and have to load the
1396 * private key instead
1397 */
1398 if (id->key && id->key->type != KEY_RSA1) {
1399 debug("Offering public key: %s", id->filename);
1400 sent = send_pubkey_test(authctxt, id);
1401 } else if (id->key == NULL) {
1402 debug("Trying private key: %s", id->filename);
1403 id->key = load_identity_file(id->filename);
1404 if (id->key != NULL) {
1405 id->isprivate = 1;
1406 sent = sign_and_send_pubkey(authctxt, id);
1407 key_free(id->key);
1408 id->key = NULL;
1409 }
1410 }
1411 if (sent)
1412 return (sent);
1413 }
1414 return (0);
1415 }
1416
1417 /*
1418 * Send userauth request message specifying keyboard-interactive method.
1419 */
1420 int
1421 userauth_kbdint(Authctxt *authctxt)
1422 {
1423 static int attempt = 0;
1424
1425 if (attempt++ >= options.number_of_password_prompts)
1426 return 0;
1427 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1428 if (attempt > 1 && !authctxt->info_req_seen) {
1429 debug3("userauth_kbdint: disable: no info_req_seen");
1430 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1431 return 0;
1432 }
1433
1434 debug2("userauth_kbdint");
1435 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1436 packet_put_cstring(authctxt->server_user);
1437 packet_put_cstring(authctxt->service);
1438 packet_put_cstring(authctxt->method->name);
1439 packet_put_cstring(""); /* lang */
1440 packet_put_cstring(options.kbd_interactive_devices ?
1441 options.kbd_interactive_devices : "");
1442 packet_send();
1443
1444 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1445 return 1;
1446 }
1447
1448 /*
1449 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1450 */
1451 void
1452 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1453 {
1454 Authctxt *authctxt = ctxt;
1455 char *name, *inst, *lang, *prompt, *response;
1456 u_int num_prompts, i;
1457 int echo = 0;
1458
1459 debug2("input_userauth_info_req");
1460
1461 if (authctxt == NULL)
1462 fatal("input_userauth_info_req: no authentication context");
1463
1464 authctxt->info_req_seen = 1;
1465
1466 name = packet_get_string(NULL);
1467 inst = packet_get_string(NULL);
1468 lang = packet_get_string(NULL);
1469 if (strlen(name) > 0)
1470 logit("%s", name);
1471 if (strlen(inst) > 0)
1472 logit("%s", inst);
1473 xfree(name);
1474 xfree(inst);
1475 xfree(lang);
1476
1477 num_prompts = packet_get_int();
1478 /*
1479 * Begin to build info response packet based on prompts requested.
1480 * We commit to providing the correct number of responses, so if
1481 * further on we run into a problem that prevents this, we have to
1482 * be sure and clean this up and send a correct error response.
1483 */
1484 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1485 packet_put_int(num_prompts);
1486
1487 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1488 for (i = 0; i < num_prompts; i++) {
1489 prompt = packet_get_string(NULL);
1490 echo = packet_get_char();
1491
1492 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1493
1494 packet_put_cstring(response);
1495 memset(response, 0, strlen(response));
1496 xfree(response);
1497 xfree(prompt);
1498 }
1499 packet_check_eom(); /* done with parsing incoming message. */
1500
1501 packet_add_padding(64);
1502 packet_send();
1503 }
1504
1505 static int
1506 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1507 u_char *data, u_int datalen)
1508 {
1509 Buffer b;
1510 struct stat st;
1511 pid_t pid;
1512 int to[2], from[2], status, version = 2;
1513
1514 debug2("ssh_keysign called");
1515
1516 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1517 error("ssh_keysign: no installed: %s", strerror(errno));
1518 return -1;
1519 }
1520 if (fflush(stdout) != 0)
1521 error("ssh_keysign: fflush: %s", strerror(errno));
1522 if (pipe(to) < 0) {
1523 error("ssh_keysign: pipe: %s", strerror(errno));
1524 return -1;
1525 }
1526 if (pipe(from) < 0) {
1527 error("ssh_keysign: pipe: %s", strerror(errno));
1528 return -1;
1529 }
1530 if ((pid = fork()) < 0) {
1531 error("ssh_keysign: fork: %s", strerror(errno));
1532 return -1;
1533 }
1534 if (pid == 0) {
1535 /* keep the socket on exec */
1536 fcntl(packet_get_connection_in(), F_SETFD, 0);
1537 permanently_drop_suid(getuid());
1538 close(from[0]);
1539 if (dup2(from[1], STDOUT_FILENO) < 0)
1540 fatal("ssh_keysign: dup2: %s", strerror(errno));
1541 close(to[1]);
1542 if (dup2(to[0], STDIN_FILENO) < 0)
1543 fatal("ssh_keysign: dup2: %s", strerror(errno));
1544 close(from[1]);
1545 close(to[0]);
1546 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1547 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1548 strerror(errno));
1549 }
1550 close(from[1]);
1551 close(to[0]);
1552
1553 buffer_init(&b);
1554 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1555 buffer_put_string(&b, data, datalen);
1556 if (ssh_msg_send(to[1], version, &b) == -1)
1557 fatal("ssh_keysign: couldn't send request");
1558
1559 if (ssh_msg_recv(from[0], &b) < 0) {
1560 error("ssh_keysign: no reply");
1561 buffer_free(&b);
1562 return -1;
1563 }
1564 close(from[0]);
1565 close(to[1]);
1566
1567 while (waitpid(pid, &status, 0) < 0)
1568 if (errno != EINTR)
1569 break;
1570
1571 if (buffer_get_char(&b) != version) {
1572 error("ssh_keysign: bad version");
1573 buffer_free(&b);
1574 return -1;
1575 }
1576 *sigp = buffer_get_string(&b, lenp);
1577 buffer_free(&b);
1578
1579 return 0;
1580 }
1581
1582 int
1583 userauth_hostbased(Authctxt *authctxt)
1584 {
1585 Key *private = NULL;
1586 Sensitive *sensitive = authctxt->sensitive;
1587 Buffer b;
1588 u_char *signature, *blob;
1589 char *chost, *pkalg, *p, myname[NI_MAXHOST];
1590 const char *service;
1591 u_int blen, slen;
1592 int ok, i, len, found = 0;
1593
1594 /* check for a useful key */
1595 for (i = 0; i < sensitive->nkeys; i++) {
1596 private = sensitive->keys[i];
1597 if (private && private->type != KEY_RSA1) {
1598 found = 1;
1599 /* we take and free the key */
1600 sensitive->keys[i] = NULL;
1601 break;
1602 }
1603 }
1604 if (!found) {
1605 debug("No more client hostkeys for hostbased authentication.");
1606 return 0;
1607 }
1608 if (key_to_blob(private, &blob, &blen) == 0) {
1609 key_free(private);
1610 return 0;
1611 }
1612 /* figure out a name for the client host */
1613 p = NULL;
1614 if (packet_connection_is_on_socket())
1615 p = get_local_name(packet_get_connection_in());
1616 if (p == NULL) {
1617 if (gethostname(myname, sizeof(myname)) == -1) {
1618 verbose("userauth_hostbased: gethostname: %s",
1619 strerror(errno));
1620 } else
1621 p = xstrdup(myname);
1622 }
1623 if (p == NULL) {
1624 error("userauth_hostbased: cannot get local ipaddr/name");
1625 key_free(private);
1626 xfree(blob);
1627 return 0;
1628 }
1629 len = strlen(p) + 2;
1630 xasprintf(&chost, "%s.", p);
1631 debug2("userauth_hostbased: chost %s", chost);
1632 xfree(p);
1633
1634 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1635 authctxt->service;
1636 pkalg = xstrdup(key_ssh_name(private));
1637 buffer_init(&b);
1638 /* construct data */
1639 buffer_put_string(&b, session_id2, session_id2_len);
1640 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1641 buffer_put_cstring(&b, authctxt->server_user);
1642 buffer_put_cstring(&b, service);
1643 buffer_put_cstring(&b, authctxt->method->name);
1644 buffer_put_cstring(&b, pkalg);
1645 buffer_put_string(&b, blob, blen);
1646 buffer_put_cstring(&b, chost);
1647 buffer_put_cstring(&b, authctxt->local_user);
1648 #ifdef DEBUG_PK
1649 buffer_dump(&b);
1650 #endif
1651 if (sensitive->external_keysign)
1652 ok = ssh_keysign(private, &signature, &slen,
1653 buffer_ptr(&b), buffer_len(&b));
1654 else
1655 ok = key_sign(private, &signature, &slen,
1656 buffer_ptr(&b), buffer_len(&b));
1657 key_free(private);
1658 buffer_free(&b);
1659 if (ok != 0) {
1660 error("key_sign failed");
1661 xfree(chost);
1662 xfree(pkalg);
1663 xfree(blob);
1664 return 0;
1665 }
1666 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1667 packet_put_cstring(authctxt->server_user);
1668 packet_put_cstring(authctxt->service);
1669 packet_put_cstring(authctxt->method->name);
1670 packet_put_cstring(pkalg);
1671 packet_put_string(blob, blen);
1672 packet_put_cstring(chost);
1673 packet_put_cstring(authctxt->local_user);
1674 packet_put_string(signature, slen);
1675 memset(signature, 's', slen);
1676 xfree(signature);
1677 xfree(chost);
1678 xfree(pkalg);
1679 xfree(blob);
1680
1681 packet_send();
1682 return 1;
1683 }
1684
1685 #ifdef JPAKE
1686 int
1687 userauth_jpake(Authctxt *authctxt)
1688 {
1689 struct jpake_ctx *pctx;
1690 u_char *x1_proof, *x2_proof;
1691 u_int x1_proof_len, x2_proof_len;
1692 static int attempt = 0; /* XXX share with userauth_password's? */
1693
1694 if (attempt++ >= options.number_of_password_prompts)
1695 return 0;
1696 if (attempt != 1)
1697 error("Permission denied, please try again.");
1698
1699 if (authctxt->methoddata != NULL)
1700 fatal("%s: authctxt->methoddata already set (%p)",
1701 __func__, authctxt->methoddata);
1702
1703 authctxt->methoddata = pctx = jpake_new();
1704
1705 /*
1706 * Send request immediately, to get the protocol going while
1707 * we do the initial computations.
1708 */
1709 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1710 packet_put_cstring(authctxt->server_user);
1711 packet_put_cstring(authctxt->service);
1712 packet_put_cstring(authctxt->method->name);
1713 packet_send();
1714 packet_write_wait();
1715
1716 jpake_step1(pctx->grp,
1717 &pctx->client_id, &pctx->client_id_len,
1718 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1719 &x1_proof, &x1_proof_len,
1720 &x2_proof, &x2_proof_len);
1721
1722 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1723
1724 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1725 packet_put_string(pctx->client_id, pctx->client_id_len);
1726 packet_put_bignum2(pctx->g_x1);
1727 packet_put_bignum2(pctx->g_x2);
1728 packet_put_string(x1_proof, x1_proof_len);
1729 packet_put_string(x2_proof, x2_proof_len);
1730 packet_send();
1731
1732 bzero(x1_proof, x1_proof_len);
1733 bzero(x2_proof, x2_proof_len);
1734 xfree(x1_proof);
1735 xfree(x2_proof);
1736
1737 /* Expect step 1 packet from peer */
1738 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1739 input_userauth_jpake_server_step1);
1740 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS,
1741 &input_userauth_success_unexpected);
1742
1743 return 1;
1744 }
1745
1746 void
1747 userauth_jpake_cleanup(Authctxt *authctxt)
1748 {
1749 debug3("%s: clean up", __func__);
1750 if (authctxt->methoddata != NULL) {
1751 jpake_free(authctxt->methoddata);
1752 authctxt->methoddata = NULL;
1753 }
1754 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
1755 }
1756 #endif /* JPAKE */
1757
1758 /* find auth method */
1759
1760 /*
1761 * given auth method name, if configurable options permit this method fill
1762 * in auth_ident field and return true, otherwise return false.
1763 */
1764 static int
1765 authmethod_is_enabled(Authmethod *method)
1766 {
1767 if (method == NULL)
1768 return 0;
1769 /* return false if options indicate this method is disabled */
1770 if (method->enabled == NULL || *method->enabled == 0)
1771 return 0;
1772 /* return false if batch mode is enabled but method needs interactive mode */
1773 if (method->batch_flag != NULL && *method->batch_flag != 0)
1774 return 0;
1775 return 1;
1776 }
1777
1778 static Authmethod *
1779 authmethod_lookup(const char *name)
1780 {
1781 Authmethod *method = NULL;
1782 if (name != NULL)
1783 for (method = authmethods; method->name != NULL; method++)
1784 if (strcmp(name, method->name) == 0)
1785 return method;
1786 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1787 return NULL;
1788 }
1789
1790 /* XXX internal state */
1791 static Authmethod *current = NULL;
1792 static char *supported = NULL;
1793 static char *preferred = NULL;
1794
1795 /*
1796 * Given the authentication method list sent by the server, return the
1797 * next method we should try. If the server initially sends a nil list,
1798 * use a built-in default list.
1799 */
1800 static Authmethod *
1801 authmethod_get(char *authlist)
1802 {
1803 char *name = NULL;
1804 u_int next;
1805
1806 /* Use a suitable default if we're passed a nil list. */
1807 if (authlist == NULL || strlen(authlist) == 0)
1808 authlist = options.preferred_authentications;
1809
1810 if (supported == NULL || strcmp(authlist, supported) != 0) {
1811 debug3("start over, passed a different list %s", authlist);
1812 if (supported != NULL)
1813 xfree(supported);
1814 supported = xstrdup(authlist);
1815 preferred = options.preferred_authentications;
1816 debug3("preferred %s", preferred);
1817 current = NULL;
1818 } else if (current != NULL && authmethod_is_enabled(current))
1819 return current;
1820
1821 for (;;) {
1822 if ((name = match_list(preferred, supported, &next)) == NULL) {
1823 debug("No more authentication methods to try.");
1824 current = NULL;
1825 return NULL;
1826 }
1827 preferred += next;
1828 debug3("authmethod_lookup %s", name);
1829 debug3("remaining preferred: %s", preferred);
1830 if ((current = authmethod_lookup(name)) != NULL &&
1831 authmethod_is_enabled(current)) {
1832 debug3("authmethod_is_enabled %s", name);
1833 debug("Next authentication method: %s", name);
1834 return current;
1835 }
1836 }
1837 }
1838
1839 static char *
1840 authmethods_get(void)
1841 {
1842 Authmethod *method = NULL;
1843 Buffer b;
1844 char *list;
1845
1846 buffer_init(&b);
1847 for (method = authmethods; method->name != NULL; method++) {
1848 if (authmethod_is_enabled(method)) {
1849 if (buffer_len(&b) > 0)
1850 buffer_append(&b, ",", 1);
1851 buffer_append(&b, method->name, strlen(method->name));
1852 }
1853 }
1854 buffer_append(&b, "\0", 1);
1855 list = xstrdup(buffer_ptr(&b));
1856 buffer_free(&b);
1857 return list;
1858 }
1859
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