Add README.DELETED to the OpenSSH's vendor branch.
[dragonfly.git] / crypto / openssh / sshconnect2.c
CommitLineData
3b69e377 1/* $OpenBSD: sshconnect2.c,v 1.166 2008/07/17 08:48:00 djm Exp $ */
16c343f1
PA
2/*
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "includes.h"
27
28#include <sys/types.h>
29#include <sys/socket.h>
30#include <sys/wait.h>
31#include <sys/stat.h>
32
33#include <errno.h>
34#include <netdb.h>
35#include <pwd.h>
36#include <signal.h>
37#include <stdarg.h>
38#include <stdio.h>
39#include <string.h>
40#include <unistd.h>
3b69e377
PA
41#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H)
42#include <vis.h>
43#endif
16c343f1
PA
44
45#include "openbsd-compat/sys-queue.h"
46
47#include "xmalloc.h"
48#include "ssh.h"
49#include "ssh2.h"
50#include "buffer.h"
51#include "packet.h"
52#include "compat.h"
53#include "cipher.h"
54#include "key.h"
55#include "kex.h"
56#include "myproposal.h"
57#include "sshconnect.h"
58#include "authfile.h"
59#include "dh.h"
60#include "authfd.h"
61#include "log.h"
62#include "readconf.h"
63#include "misc.h"
64#include "match.h"
65#include "dispatch.h"
66#include "canohost.h"
67#include "msg.h"
68#include "pathnames.h"
69#include "uidswap.h"
70
71#ifdef GSSAPI
72#include "ssh-gss.h"
73#endif
74
75/* import */
76extern char *client_version_string;
77extern char *server_version_string;
78extern Options options;
79
80/*
81 * SSH2 key exchange
82 */
83
84u_char *session_id2 = NULL;
85u_int session_id2_len = 0;
86
87char *xxx_host;
88struct sockaddr *xxx_hostaddr;
89
90Kex *xxx_kex = NULL;
91
92static int
93verify_host_key_callback(Key *hostkey)
94{
95 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
96 fatal("Host key verification failed.");
97 return 0;
98}
99
100void
101ssh_kex2(char *host, struct sockaddr *hostaddr)
102{
103 Kex *kex;
104
105 xxx_host = host;
106 xxx_hostaddr = hostaddr;
107
108 if (options.ciphers == (char *)-1) {
109 logit("No valid ciphers for protocol version 2 given, using defaults.");
110 options.ciphers = NULL;
111 }
112 if (options.ciphers != NULL) {
113 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
114 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
115 }
116 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
117 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
118 myproposal[PROPOSAL_ENC_ALGS_STOC] =
119 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
120 if (options.compression) {
121 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
122 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
123 } else {
124 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
125 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
126 }
127 if (options.macs != NULL) {
128 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
129 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
130 }
131 if (options.hostkeyalgorithms != NULL)
132 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
133 options.hostkeyalgorithms;
134
135 if (options.rekey_limit)
136 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
137
138 /* start key exchange */
139 kex = kex_setup(myproposal);
140 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
141 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
142 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
143 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
144 kex->client_version_string=client_version_string;
145 kex->server_version_string=server_version_string;
146 kex->verify_host_key=&verify_host_key_callback;
147
148 xxx_kex = kex;
149
150 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
151
152 session_id2 = kex->session_id;
153 session_id2_len = kex->session_id_len;
154
155#ifdef DEBUG_KEXDH
156 /* send 1st encrypted/maced/compressed message */
157 packet_start(SSH2_MSG_IGNORE);
158 packet_put_cstring("markus");
159 packet_send();
160 packet_write_wait();
161#endif
162}
163
164/*
165 * Authenticate user
166 */
167
168typedef struct Authctxt Authctxt;
169typedef struct Authmethod Authmethod;
170typedef struct identity Identity;
171typedef struct idlist Idlist;
172
173struct identity {
174 TAILQ_ENTRY(identity) next;
175 AuthenticationConnection *ac; /* set if agent supports key */
176 Key *key; /* public/private key */
177 char *filename; /* comment for agent-only keys */
178 int tried;
179 int isprivate; /* key points to the private key */
180};
181TAILQ_HEAD(idlist, identity);
182
183struct Authctxt {
184 const char *server_user;
185 const char *local_user;
186 const char *host;
187 const char *service;
188 Authmethod *method;
189 int success;
190 char *authlist;
191 /* pubkey */
192 Idlist keys;
193 AuthenticationConnection *agent;
194 /* hostbased */
195 Sensitive *sensitive;
196 /* kbd-interactive */
197 int info_req_seen;
198 /* generic */
199 void *methoddata;
200};
201struct Authmethod {
202 char *name; /* string to compare against server's list */
203 int (*userauth)(Authctxt *authctxt);
204 int *enabled; /* flag in option struct that enables method */
205 int *batch_flag; /* flag in option struct that disables method */
206};
207
208void input_userauth_success(int, u_int32_t, void *);
209void input_userauth_failure(int, u_int32_t, void *);
210void input_userauth_banner(int, u_int32_t, void *);
211void input_userauth_error(int, u_int32_t, void *);
212void input_userauth_info_req(int, u_int32_t, void *);
213void input_userauth_pk_ok(int, u_int32_t, void *);
214void input_userauth_passwd_changereq(int, u_int32_t, void *);
215
216int userauth_none(Authctxt *);
217int userauth_pubkey(Authctxt *);
218int userauth_passwd(Authctxt *);
219int userauth_kbdint(Authctxt *);
220int userauth_hostbased(Authctxt *);
221int userauth_kerberos(Authctxt *);
222
223#ifdef GSSAPI
224int userauth_gssapi(Authctxt *authctxt);
225void input_gssapi_response(int type, u_int32_t, void *);
226void input_gssapi_token(int type, u_int32_t, void *);
227void input_gssapi_hash(int type, u_int32_t, void *);
228void input_gssapi_error(int, u_int32_t, void *);
229void input_gssapi_errtok(int, u_int32_t, void *);
230#endif
231
232void userauth(Authctxt *, char *);
233
234static int sign_and_send_pubkey(Authctxt *, Identity *);
235static void pubkey_prepare(Authctxt *);
236static void pubkey_cleanup(Authctxt *);
237static Key *load_identity_file(char *);
238
239static Authmethod *authmethod_get(char *authlist);
240static Authmethod *authmethod_lookup(const char *name);
241static char *authmethods_get(void);
242
243Authmethod authmethods[] = {
244#ifdef GSSAPI
245 {"gssapi-with-mic",
246 userauth_gssapi,
247 &options.gss_authentication,
248 NULL},
249#endif
250 {"hostbased",
251 userauth_hostbased,
252 &options.hostbased_authentication,
253 NULL},
254 {"publickey",
255 userauth_pubkey,
256 &options.pubkey_authentication,
257 NULL},
258 {"keyboard-interactive",
259 userauth_kbdint,
260 &options.kbd_interactive_authentication,
261 &options.batch_mode},
262 {"password",
263 userauth_passwd,
264 &options.password_authentication,
265 &options.batch_mode},
266 {"none",
267 userauth_none,
268 NULL,
269 NULL},
270 {NULL, NULL, NULL, NULL}
271};
272
273void
274ssh_userauth2(const char *local_user, const char *server_user, char *host,
275 Sensitive *sensitive)
276{
277 Authctxt authctxt;
278 int type;
279
280 if (options.challenge_response_authentication)
281 options.kbd_interactive_authentication = 1;
282
283 packet_start(SSH2_MSG_SERVICE_REQUEST);
284 packet_put_cstring("ssh-userauth");
285 packet_send();
286 debug("SSH2_MSG_SERVICE_REQUEST sent");
287 packet_write_wait();
288 type = packet_read();
289 if (type != SSH2_MSG_SERVICE_ACCEPT)
290 fatal("Server denied authentication request: %d", type);
291 if (packet_remaining() > 0) {
292 char *reply = packet_get_string(NULL);
293 debug2("service_accept: %s", reply);
294 xfree(reply);
295 } else {
296 debug2("buggy server: service_accept w/o service");
297 }
298 packet_check_eom();
299 debug("SSH2_MSG_SERVICE_ACCEPT received");
300
301 if (options.preferred_authentications == NULL)
302 options.preferred_authentications = authmethods_get();
303
304 /* setup authentication context */
305 memset(&authctxt, 0, sizeof(authctxt));
306 pubkey_prepare(&authctxt);
307 authctxt.server_user = server_user;
308 authctxt.local_user = local_user;
309 authctxt.host = host;
310 authctxt.service = "ssh-connection"; /* service name */
311 authctxt.success = 0;
312 authctxt.method = authmethod_lookup("none");
313 authctxt.authlist = NULL;
314 authctxt.methoddata = NULL;
315 authctxt.sensitive = sensitive;
316 authctxt.info_req_seen = 0;
317 if (authctxt.method == NULL)
318 fatal("ssh_userauth2: internal error: cannot send userauth none request");
319
320 /* initial userauth request */
321 userauth_none(&authctxt);
322
323 dispatch_init(&input_userauth_error);
324 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
325 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
326 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
327 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
328
329 pubkey_cleanup(&authctxt);
330 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
331
332 debug("Authentication succeeded (%s).", authctxt.method->name);
333}
334
335void
336userauth(Authctxt *authctxt, char *authlist)
337{
338 if (authctxt->methoddata) {
339 xfree(authctxt->methoddata);
340 authctxt->methoddata = NULL;
341 }
342 if (authlist == NULL) {
343 authlist = authctxt->authlist;
344 } else {
345 if (authctxt->authlist)
346 xfree(authctxt->authlist);
347 authctxt->authlist = authlist;
348 }
349 for (;;) {
350 Authmethod *method = authmethod_get(authlist);
351 if (method == NULL)
352 fatal("Permission denied (%s).", authlist);
353 authctxt->method = method;
354
355 /* reset the per method handler */
356 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
357 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
358
359 /* and try new method */
360 if (method->userauth(authctxt) != 0) {
361 debug2("we sent a %s packet, wait for reply", method->name);
362 break;
363 } else {
364 debug2("we did not send a packet, disable method");
365 method->enabled = NULL;
366 }
367 }
368}
369
370void
371input_userauth_error(int type, u_int32_t seq, void *ctxt)
372{
373 fatal("input_userauth_error: bad message during authentication: "
374 "type %d", type);
375}
376
377void
378input_userauth_banner(int type, u_int32_t seq, void *ctxt)
379{
3b69e377
PA
380 char *msg, *raw, *lang;
381 u_int len;
16c343f1
PA
382
383 debug3("input_userauth_banner");
3b69e377 384 raw = packet_get_string(&len);
16c343f1 385 lang = packet_get_string(NULL);
3b69e377
PA
386 if (options.log_level >= SYSLOG_LEVEL_INFO) {
387 if (len > 65536)
388 len = 65536;
389 msg = xmalloc(len * 4); /* max expansion from strnvis() */
390 strnvis(msg, raw, len * 4, VIS_SAFE|VIS_OCTAL);
16c343f1 391 fprintf(stderr, "%s", msg);
3b69e377
PA
392 xfree(msg);
393 }
394 xfree(raw);
16c343f1
PA
395 xfree(lang);
396}
397
398void
399input_userauth_success(int type, u_int32_t seq, void *ctxt)
400{
401 Authctxt *authctxt = ctxt;
402 if (authctxt == NULL)
403 fatal("input_userauth_success: no authentication context");
404 if (authctxt->authlist) {
405 xfree(authctxt->authlist);
406 authctxt->authlist = NULL;
407 }
408 if (authctxt->methoddata) {
409 xfree(authctxt->methoddata);
410 authctxt->methoddata = NULL;
411 }
412 authctxt->success = 1; /* break out */
413}
414
415void
416input_userauth_failure(int type, u_int32_t seq, void *ctxt)
417{
418 Authctxt *authctxt = ctxt;
419 char *authlist = NULL;
420 int partial;
421
422 if (authctxt == NULL)
423 fatal("input_userauth_failure: no authentication context");
424
425 authlist = packet_get_string(NULL);
426 partial = packet_get_char();
427 packet_check_eom();
428
429 if (partial != 0)
430 logit("Authenticated with partial success.");
431 debug("Authentications that can continue: %s", authlist);
432
433 userauth(authctxt, authlist);
434}
435void
436input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
437{
438 Authctxt *authctxt = ctxt;
439 Key *key = NULL;
440 Identity *id = NULL;
441 Buffer b;
442 int pktype, sent = 0;
443 u_int alen, blen;
444 char *pkalg, *fp;
445 u_char *pkblob;
446
447 if (authctxt == NULL)
448 fatal("input_userauth_pk_ok: no authentication context");
449 if (datafellows & SSH_BUG_PKOK) {
450 /* this is similar to SSH_BUG_PKAUTH */
451 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
452 pkblob = packet_get_string(&blen);
453 buffer_init(&b);
454 buffer_append(&b, pkblob, blen);
455 pkalg = buffer_get_string(&b, &alen);
456 buffer_free(&b);
457 } else {
458 pkalg = packet_get_string(&alen);
459 pkblob = packet_get_string(&blen);
460 }
461 packet_check_eom();
462
463 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
464
465 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
466 debug("unknown pkalg %s", pkalg);
467 goto done;
468 }
469 if ((key = key_from_blob(pkblob, blen)) == NULL) {
470 debug("no key from blob. pkalg %s", pkalg);
471 goto done;
472 }
473 if (key->type != pktype) {
474 error("input_userauth_pk_ok: type mismatch "
475 "for decoded key (received %d, expected %d)",
476 key->type, pktype);
477 goto done;
478 }
479 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
480 debug2("input_userauth_pk_ok: fp %s", fp);
481 xfree(fp);
482
483 /*
484 * search keys in the reverse order, because last candidate has been
485 * moved to the end of the queue. this also avoids confusion by
486 * duplicate keys
487 */
488 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
489 if (key_equal(key, id->key)) {
490 sent = sign_and_send_pubkey(authctxt, id);
491 break;
492 }
493 }
494done:
495 if (key != NULL)
496 key_free(key);
497 xfree(pkalg);
498 xfree(pkblob);
499
500 /* try another method if we did not send a packet */
501 if (sent == 0)
502 userauth(authctxt, NULL);
503}
504
505#ifdef GSSAPI
506int
507userauth_gssapi(Authctxt *authctxt)
508{
509 Gssctxt *gssctxt = NULL;
510 static gss_OID_set gss_supported = NULL;
511 static u_int mech = 0;
512 OM_uint32 min;
513 int ok = 0;
514
515 /* Try one GSSAPI method at a time, rather than sending them all at
516 * once. */
517
518 if (gss_supported == NULL)
519 gss_indicate_mechs(&min, &gss_supported);
520
521 /* Check to see if the mechanism is usable before we offer it */
522 while (mech < gss_supported->count && !ok) {
523 /* My DER encoding requires length<128 */
524 if (gss_supported->elements[mech].length < 128 &&
525 ssh_gssapi_check_mechanism(&gssctxt,
526 &gss_supported->elements[mech], authctxt->host)) {
527 ok = 1; /* Mechanism works */
528 } else {
529 mech++;
530 }
531 }
532
533 if (!ok)
534 return 0;
535
536 authctxt->methoddata=(void *)gssctxt;
537
538 packet_start(SSH2_MSG_USERAUTH_REQUEST);
539 packet_put_cstring(authctxt->server_user);
540 packet_put_cstring(authctxt->service);
541 packet_put_cstring(authctxt->method->name);
542
543 packet_put_int(1);
544
545 packet_put_int((gss_supported->elements[mech].length) + 2);
546 packet_put_char(SSH_GSS_OIDTYPE);
547 packet_put_char(gss_supported->elements[mech].length);
548 packet_put_raw(gss_supported->elements[mech].elements,
549 gss_supported->elements[mech].length);
550
551 packet_send();
552
553 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
554 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
555 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
556 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
557
558 mech++; /* Move along to next candidate */
559
560 return 1;
561}
562
563static OM_uint32
564process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
565{
566 Authctxt *authctxt = ctxt;
567 Gssctxt *gssctxt = authctxt->methoddata;
568 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
569 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
570 gss_buffer_desc gssbuf;
571 OM_uint32 status, ms, flags;
572 Buffer b;
573
574 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
575 recv_tok, &send_tok, &flags);
576
577 if (send_tok.length > 0) {
578 if (GSS_ERROR(status))
579 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
580 else
581 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
582
583 packet_put_string(send_tok.value, send_tok.length);
584 packet_send();
585 gss_release_buffer(&ms, &send_tok);
586 }
587
588 if (status == GSS_S_COMPLETE) {
589 /* send either complete or MIC, depending on mechanism */
590 if (!(flags & GSS_C_INTEG_FLAG)) {
591 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
592 packet_send();
593 } else {
594 ssh_gssapi_buildmic(&b, authctxt->server_user,
595 authctxt->service, "gssapi-with-mic");
596
597 gssbuf.value = buffer_ptr(&b);
598 gssbuf.length = buffer_len(&b);
599
600 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
601
602 if (!GSS_ERROR(status)) {
603 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
604 packet_put_string(mic.value, mic.length);
605
606 packet_send();
607 }
608
609 buffer_free(&b);
610 gss_release_buffer(&ms, &mic);
611 }
612 }
613
614 return status;
615}
616
617void
618input_gssapi_response(int type, u_int32_t plen, void *ctxt)
619{
620 Authctxt *authctxt = ctxt;
621 Gssctxt *gssctxt;
622 int oidlen;
623 char *oidv;
624
625 if (authctxt == NULL)
626 fatal("input_gssapi_response: no authentication context");
627 gssctxt = authctxt->methoddata;
628
629 /* Setup our OID */
630 oidv = packet_get_string(&oidlen);
631
632 if (oidlen <= 2 ||
633 oidv[0] != SSH_GSS_OIDTYPE ||
634 oidv[1] != oidlen - 2) {
635 xfree(oidv);
636 debug("Badly encoded mechanism OID received");
637 userauth(authctxt, NULL);
638 return;
639 }
640
641 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
642 fatal("Server returned different OID than expected");
643
644 packet_check_eom();
645
646 xfree(oidv);
647
648 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
649 /* Start again with next method on list */
650 debug("Trying to start again");
651 userauth(authctxt, NULL);
652 return;
653 }
654}
655
656void
657input_gssapi_token(int type, u_int32_t plen, void *ctxt)
658{
659 Authctxt *authctxt = ctxt;
660 gss_buffer_desc recv_tok;
661 OM_uint32 status;
662 u_int slen;
663
664 if (authctxt == NULL)
665 fatal("input_gssapi_response: no authentication context");
666
667 recv_tok.value = packet_get_string(&slen);
668 recv_tok.length = slen; /* safe typecast */
669
670 packet_check_eom();
671
672 status = process_gssapi_token(ctxt, &recv_tok);
673
674 xfree(recv_tok.value);
675
676 if (GSS_ERROR(status)) {
677 /* Start again with the next method in the list */
678 userauth(authctxt, NULL);
679 return;
680 }
681}
682
683void
684input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
685{
686 Authctxt *authctxt = ctxt;
687 Gssctxt *gssctxt;
688 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
689 gss_buffer_desc recv_tok;
690 OM_uint32 status, ms;
691 u_int len;
692
693 if (authctxt == NULL)
694 fatal("input_gssapi_response: no authentication context");
695 gssctxt = authctxt->methoddata;
696
697 recv_tok.value = packet_get_string(&len);
698 recv_tok.length = len;
699
700 packet_check_eom();
701
702 /* Stick it into GSSAPI and see what it says */
703 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
704 &recv_tok, &send_tok, NULL);
705
706 xfree(recv_tok.value);
707 gss_release_buffer(&ms, &send_tok);
708
709 /* Server will be returning a failed packet after this one */
710}
711
712void
713input_gssapi_error(int type, u_int32_t plen, void *ctxt)
714{
715 OM_uint32 maj, min;
716 char *msg;
717 char *lang;
718
719 maj=packet_get_int();
720 min=packet_get_int();
721 msg=packet_get_string(NULL);
722 lang=packet_get_string(NULL);
723
724 packet_check_eom();
725
726 debug("Server GSSAPI Error:\n%s", msg);
727 xfree(msg);
728 xfree(lang);
729}
730#endif /* GSSAPI */
731
732int
733userauth_none(Authctxt *authctxt)
734{
735 /* initial userauth request */
736 packet_start(SSH2_MSG_USERAUTH_REQUEST);
737 packet_put_cstring(authctxt->server_user);
738 packet_put_cstring(authctxt->service);
739 packet_put_cstring(authctxt->method->name);
740 packet_send();
741 return 1;
742}
743
744int
745userauth_passwd(Authctxt *authctxt)
746{
747 static int attempt = 0;
748 char prompt[150];
749 char *password;
750
751 if (attempt++ >= options.number_of_password_prompts)
752 return 0;
753
754 if (attempt != 1)
755 error("Permission denied, please try again.");
756
757 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
758 authctxt->server_user, authctxt->host);
759 password = read_passphrase(prompt, 0);
760 packet_start(SSH2_MSG_USERAUTH_REQUEST);
761 packet_put_cstring(authctxt->server_user);
762 packet_put_cstring(authctxt->service);
763 packet_put_cstring(authctxt->method->name);
764 packet_put_char(0);
765 packet_put_cstring(password);
766 memset(password, 0, strlen(password));
767 xfree(password);
768 packet_add_padding(64);
769 packet_send();
770
771 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
772 &input_userauth_passwd_changereq);
773
774 return 1;
775}
776/*
777 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
778 */
779void
780input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
781{
782 Authctxt *authctxt = ctxt;
783 char *info, *lang, *password = NULL, *retype = NULL;
784 char prompt[150];
785
786 debug2("input_userauth_passwd_changereq");
787
788 if (authctxt == NULL)
789 fatal("input_userauth_passwd_changereq: "
790 "no authentication context");
791
792 info = packet_get_string(NULL);
793 lang = packet_get_string(NULL);
794 if (strlen(info) > 0)
795 logit("%s", info);
796 xfree(info);
797 xfree(lang);
798 packet_start(SSH2_MSG_USERAUTH_REQUEST);
799 packet_put_cstring(authctxt->server_user);
800 packet_put_cstring(authctxt->service);
801 packet_put_cstring(authctxt->method->name);
802 packet_put_char(1); /* additional info */
803 snprintf(prompt, sizeof(prompt),
804 "Enter %.30s@%.128s's old password: ",
805 authctxt->server_user, authctxt->host);
806 password = read_passphrase(prompt, 0);
807 packet_put_cstring(password);
808 memset(password, 0, strlen(password));
809 xfree(password);
810 password = NULL;
811 while (password == NULL) {
812 snprintf(prompt, sizeof(prompt),
813 "Enter %.30s@%.128s's new password: ",
814 authctxt->server_user, authctxt->host);
815 password = read_passphrase(prompt, RP_ALLOW_EOF);
816 if (password == NULL) {
817 /* bail out */
818 return;
819 }
820 snprintf(prompt, sizeof(prompt),
821 "Retype %.30s@%.128s's new password: ",
822 authctxt->server_user, authctxt->host);
823 retype = read_passphrase(prompt, 0);
824 if (strcmp(password, retype) != 0) {
825 memset(password, 0, strlen(password));
826 xfree(password);
827 logit("Mismatch; try again, EOF to quit.");
828 password = NULL;
829 }
830 memset(retype, 0, strlen(retype));
831 xfree(retype);
832 }
833 packet_put_cstring(password);
834 memset(password, 0, strlen(password));
835 xfree(password);
836 packet_add_padding(64);
837 packet_send();
838
839 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
840 &input_userauth_passwd_changereq);
841}
842
843static int
844identity_sign(Identity *id, u_char **sigp, u_int *lenp,
845 u_char *data, u_int datalen)
846{
847 Key *prv;
848 int ret;
849
850 /* the agent supports this key */
851 if (id->ac)
852 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
853 data, datalen));
854 /*
855 * we have already loaded the private key or
856 * the private key is stored in external hardware
857 */
858 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
859 return (key_sign(id->key, sigp, lenp, data, datalen));
860 /* load the private key from the file */
861 if ((prv = load_identity_file(id->filename)) == NULL)
862 return (-1);
863 ret = key_sign(prv, sigp, lenp, data, datalen);
864 key_free(prv);
865 return (ret);
866}
867
868static int
869sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
870{
871 Buffer b;
872 u_char *blob, *signature;
873 u_int bloblen, slen;
874 u_int skip = 0;
875 int ret = -1;
876 int have_sig = 1;
877
878 debug3("sign_and_send_pubkey");
879
880 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
881 /* we cannot handle this key */
882 debug3("sign_and_send_pubkey: cannot handle key");
883 return 0;
884 }
885 /* data to be signed */
886 buffer_init(&b);
887 if (datafellows & SSH_OLD_SESSIONID) {
888 buffer_append(&b, session_id2, session_id2_len);
889 skip = session_id2_len;
890 } else {
891 buffer_put_string(&b, session_id2, session_id2_len);
892 skip = buffer_len(&b);
893 }
894 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
895 buffer_put_cstring(&b, authctxt->server_user);
896 buffer_put_cstring(&b,
897 datafellows & SSH_BUG_PKSERVICE ?
898 "ssh-userauth" :
899 authctxt->service);
900 if (datafellows & SSH_BUG_PKAUTH) {
901 buffer_put_char(&b, have_sig);
902 } else {
903 buffer_put_cstring(&b, authctxt->method->name);
904 buffer_put_char(&b, have_sig);
905 buffer_put_cstring(&b, key_ssh_name(id->key));
906 }
907 buffer_put_string(&b, blob, bloblen);
908
909 /* generate signature */
910 ret = identity_sign(id, &signature, &slen,
911 buffer_ptr(&b), buffer_len(&b));
912 if (ret == -1) {
913 xfree(blob);
914 buffer_free(&b);
915 return 0;
916 }
917#ifdef DEBUG_PK
918 buffer_dump(&b);
919#endif
920 if (datafellows & SSH_BUG_PKSERVICE) {
921 buffer_clear(&b);
922 buffer_append(&b, session_id2, session_id2_len);
923 skip = session_id2_len;
924 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
925 buffer_put_cstring(&b, authctxt->server_user);
926 buffer_put_cstring(&b, authctxt->service);
927 buffer_put_cstring(&b, authctxt->method->name);
928 buffer_put_char(&b, have_sig);
929 if (!(datafellows & SSH_BUG_PKAUTH))
930 buffer_put_cstring(&b, key_ssh_name(id->key));
931 buffer_put_string(&b, blob, bloblen);
932 }
933 xfree(blob);
934
935 /* append signature */
936 buffer_put_string(&b, signature, slen);
937 xfree(signature);
938
939 /* skip session id and packet type */
940 if (buffer_len(&b) < skip + 1)
941 fatal("userauth_pubkey: internal error");
942 buffer_consume(&b, skip + 1);
943
944 /* put remaining data from buffer into packet */
945 packet_start(SSH2_MSG_USERAUTH_REQUEST);
946 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
947 buffer_free(&b);
948 packet_send();
949
950 return 1;
951}
952
953static int
954send_pubkey_test(Authctxt *authctxt, Identity *id)
955{
956 u_char *blob;
957 u_int bloblen, have_sig = 0;
958
959 debug3("send_pubkey_test");
960
961 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
962 /* we cannot handle this key */
963 debug3("send_pubkey_test: cannot handle key");
964 return 0;
965 }
966 /* register callback for USERAUTH_PK_OK message */
967 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
968
969 packet_start(SSH2_MSG_USERAUTH_REQUEST);
970 packet_put_cstring(authctxt->server_user);
971 packet_put_cstring(authctxt->service);
972 packet_put_cstring(authctxt->method->name);
973 packet_put_char(have_sig);
974 if (!(datafellows & SSH_BUG_PKAUTH))
975 packet_put_cstring(key_ssh_name(id->key));
976 packet_put_string(blob, bloblen);
977 xfree(blob);
978 packet_send();
979 return 1;
980}
981
982static Key *
983load_identity_file(char *filename)
984{
985 Key *private;
986 char prompt[300], *passphrase;
987 int perm_ok, quit, i;
988 struct stat st;
989
990 if (stat(filename, &st) < 0) {
991 debug3("no such identity: %s", filename);
992 return NULL;
993 }
994 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
995 if (!perm_ok)
996 return NULL;
997 if (private == NULL) {
998 if (options.batch_mode)
999 return NULL;
1000 snprintf(prompt, sizeof prompt,
1001 "Enter passphrase for key '%.100s': ", filename);
1002 for (i = 0; i < options.number_of_password_prompts; i++) {
1003 passphrase = read_passphrase(prompt, 0);
1004 if (strcmp(passphrase, "") != 0) {
1005 private = key_load_private_type(KEY_UNSPEC,
1006 filename, passphrase, NULL, NULL);
1007 quit = 0;
1008 } else {
1009 debug2("no passphrase given, try next key");
1010 quit = 1;
1011 }
1012 memset(passphrase, 0, strlen(passphrase));
1013 xfree(passphrase);
1014 if (private != NULL || quit)
1015 break;
1016 debug2("bad passphrase given, try again...");
1017 }
1018 }
1019 return private;
1020}
1021
1022/*
1023 * try keys in the following order:
1024 * 1. agent keys that are found in the config file
1025 * 2. other agent keys
1026 * 3. keys that are only listed in the config file
1027 */
1028static void
1029pubkey_prepare(Authctxt *authctxt)
1030{
1031 Identity *id;
1032 Idlist agent, files, *preferred;
1033 Key *key;
1034 AuthenticationConnection *ac;
1035 char *comment;
1036 int i, found;
1037
1038 TAILQ_INIT(&agent); /* keys from the agent */
1039 TAILQ_INIT(&files); /* keys from the config file */
1040 preferred = &authctxt->keys;
1041 TAILQ_INIT(preferred); /* preferred order of keys */
1042
1043 /* list of keys stored in the filesystem */
1044 for (i = 0; i < options.num_identity_files; i++) {
1045 key = options.identity_keys[i];
1046 if (key && key->type == KEY_RSA1)
1047 continue;
1048 options.identity_keys[i] = NULL;
1049 id = xcalloc(1, sizeof(*id));
1050 id->key = key;
1051 id->filename = xstrdup(options.identity_files[i]);
1052 TAILQ_INSERT_TAIL(&files, id, next);
1053 }
1054 /* list of keys supported by the agent */
1055 if ((ac = ssh_get_authentication_connection())) {
1056 for (key = ssh_get_first_identity(ac, &comment, 2);
1057 key != NULL;
1058 key = ssh_get_next_identity(ac, &comment, 2)) {
1059 found = 0;
1060 TAILQ_FOREACH(id, &files, next) {
1061 /* agent keys from the config file are preferred */
1062 if (key_equal(key, id->key)) {
1063 key_free(key);
1064 xfree(comment);
1065 TAILQ_REMOVE(&files, id, next);
1066 TAILQ_INSERT_TAIL(preferred, id, next);
1067 id->ac = ac;
1068 found = 1;
1069 break;
1070 }
1071 }
1072 if (!found && !options.identities_only) {
1073 id = xcalloc(1, sizeof(*id));
1074 id->key = key;
1075 id->filename = comment;
1076 id->ac = ac;
1077 TAILQ_INSERT_TAIL(&agent, id, next);
1078 }
1079 }
1080 /* append remaining agent keys */
1081 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1082 TAILQ_REMOVE(&agent, id, next);
1083 TAILQ_INSERT_TAIL(preferred, id, next);
1084 }
1085 authctxt->agent = ac;
1086 }
1087 /* append remaining keys from the config file */
1088 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1089 TAILQ_REMOVE(&files, id, next);
1090 TAILQ_INSERT_TAIL(preferred, id, next);
1091 }
1092 TAILQ_FOREACH(id, preferred, next) {
1093 debug2("key: %s (%p)", id->filename, id->key);
1094 }
1095}
1096
1097static void
1098pubkey_cleanup(Authctxt *authctxt)
1099{
1100 Identity *id;
1101
1102 if (authctxt->agent != NULL)
1103 ssh_close_authentication_connection(authctxt->agent);
1104 for (id = TAILQ_FIRST(&authctxt->keys); id;
1105 id = TAILQ_FIRST(&authctxt->keys)) {
1106 TAILQ_REMOVE(&authctxt->keys, id, next);
1107 if (id->key)
1108 key_free(id->key);
1109 if (id->filename)
1110 xfree(id->filename);
1111 xfree(id);
1112 }
1113}
1114
1115int
1116userauth_pubkey(Authctxt *authctxt)
1117{
1118 Identity *id;
1119 int sent = 0;
1120
1121 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1122 if (id->tried++)
1123 return (0);
1124 /* move key to the end of the queue */
1125 TAILQ_REMOVE(&authctxt->keys, id, next);
1126 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1127 /*
1128 * send a test message if we have the public key. for
1129 * encrypted keys we cannot do this and have to load the
1130 * private key instead
1131 */
1132 if (id->key && id->key->type != KEY_RSA1) {
1133 debug("Offering public key: %s", id->filename);
1134 sent = send_pubkey_test(authctxt, id);
1135 } else if (id->key == NULL) {
1136 debug("Trying private key: %s", id->filename);
1137 id->key = load_identity_file(id->filename);
1138 if (id->key != NULL) {
1139 id->isprivate = 1;
1140 sent = sign_and_send_pubkey(authctxt, id);
1141 key_free(id->key);
1142 id->key = NULL;
1143 }
1144 }
1145 if (sent)
1146 return (sent);
1147 }
1148 return (0);
1149}
1150
1151/*
1152 * Send userauth request message specifying keyboard-interactive method.
1153 */
1154int
1155userauth_kbdint(Authctxt *authctxt)
1156{
1157 static int attempt = 0;
1158
1159 if (attempt++ >= options.number_of_password_prompts)
1160 return 0;
1161 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1162 if (attempt > 1 && !authctxt->info_req_seen) {
1163 debug3("userauth_kbdint: disable: no info_req_seen");
1164 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1165 return 0;
1166 }
1167
1168 debug2("userauth_kbdint");
1169 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1170 packet_put_cstring(authctxt->server_user);
1171 packet_put_cstring(authctxt->service);
1172 packet_put_cstring(authctxt->method->name);
1173 packet_put_cstring(""); /* lang */
1174 packet_put_cstring(options.kbd_interactive_devices ?
1175 options.kbd_interactive_devices : "");
1176 packet_send();
1177
1178 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1179 return 1;
1180}
1181
1182/*
1183 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1184 */
1185void
1186input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1187{
1188 Authctxt *authctxt = ctxt;
1189 char *name, *inst, *lang, *prompt, *response;
1190 u_int num_prompts, i;
1191 int echo = 0;
1192
1193 debug2("input_userauth_info_req");
1194
1195 if (authctxt == NULL)
1196 fatal("input_userauth_info_req: no authentication context");
1197
1198 authctxt->info_req_seen = 1;
1199
1200 name = packet_get_string(NULL);
1201 inst = packet_get_string(NULL);
1202 lang = packet_get_string(NULL);
1203 if (strlen(name) > 0)
1204 logit("%s", name);
1205 if (strlen(inst) > 0)
1206 logit("%s", inst);
1207 xfree(name);
1208 xfree(inst);
1209 xfree(lang);
1210
1211 num_prompts = packet_get_int();
1212 /*
1213 * Begin to build info response packet based on prompts requested.
1214 * We commit to providing the correct number of responses, so if
1215 * further on we run into a problem that prevents this, we have to
1216 * be sure and clean this up and send a correct error response.
1217 */
1218 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1219 packet_put_int(num_prompts);
1220
1221 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1222 for (i = 0; i < num_prompts; i++) {
1223 prompt = packet_get_string(NULL);
1224 echo = packet_get_char();
1225
1226 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1227
1228 packet_put_cstring(response);
1229 memset(response, 0, strlen(response));
1230 xfree(response);
1231 xfree(prompt);
1232 }
1233 packet_check_eom(); /* done with parsing incoming message. */
1234
1235 packet_add_padding(64);
1236 packet_send();
1237}
1238
1239static int
1240ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1241 u_char *data, u_int datalen)
1242{
1243 Buffer b;
1244 struct stat st;
1245 pid_t pid;
1246 int to[2], from[2], status, version = 2;
1247
1248 debug2("ssh_keysign called");
1249
1250 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1251 error("ssh_keysign: no installed: %s", strerror(errno));
1252 return -1;
1253 }
1254 if (fflush(stdout) != 0)
1255 error("ssh_keysign: fflush: %s", strerror(errno));
1256 if (pipe(to) < 0) {
1257 error("ssh_keysign: pipe: %s", strerror(errno));
1258 return -1;
1259 }
1260 if (pipe(from) < 0) {
1261 error("ssh_keysign: pipe: %s", strerror(errno));
1262 return -1;
1263 }
1264 if ((pid = fork()) < 0) {
1265 error("ssh_keysign: fork: %s", strerror(errno));
1266 return -1;
1267 }
1268 if (pid == 0) {
1269 permanently_drop_suid(getuid());
1270 close(from[0]);
1271 if (dup2(from[1], STDOUT_FILENO) < 0)
1272 fatal("ssh_keysign: dup2: %s", strerror(errno));
1273 close(to[1]);
1274 if (dup2(to[0], STDIN_FILENO) < 0)
1275 fatal("ssh_keysign: dup2: %s", strerror(errno));
1276 close(from[1]);
1277 close(to[0]);
1278 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1279 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1280 strerror(errno));
1281 }
1282 close(from[1]);
1283 close(to[0]);
1284
1285 buffer_init(&b);
1286 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1287 buffer_put_string(&b, data, datalen);
1288 if (ssh_msg_send(to[1], version, &b) == -1)
1289 fatal("ssh_keysign: couldn't send request");
1290
1291 if (ssh_msg_recv(from[0], &b) < 0) {
1292 error("ssh_keysign: no reply");
1293 buffer_free(&b);
1294 return -1;
1295 }
1296 close(from[0]);
1297 close(to[1]);
1298
1299 while (waitpid(pid, &status, 0) < 0)
1300 if (errno != EINTR)
1301 break;
1302
1303 if (buffer_get_char(&b) != version) {
1304 error("ssh_keysign: bad version");
1305 buffer_free(&b);
1306 return -1;
1307 }
1308 *sigp = buffer_get_string(&b, lenp);
1309 buffer_free(&b);
1310
1311 return 0;
1312}
1313
1314int
1315userauth_hostbased(Authctxt *authctxt)
1316{
1317 Key *private = NULL;
1318 Sensitive *sensitive = authctxt->sensitive;
1319 Buffer b;
1320 u_char *signature, *blob;
1321 char *chost, *pkalg, *p, myname[NI_MAXHOST];
1322 const char *service;
1323 u_int blen, slen;
1324 int ok, i, len, found = 0;
1325
1326 /* check for a useful key */
1327 for (i = 0; i < sensitive->nkeys; i++) {
1328 private = sensitive->keys[i];
1329 if (private && private->type != KEY_RSA1) {
1330 found = 1;
1331 /* we take and free the key */
1332 sensitive->keys[i] = NULL;
1333 break;
1334 }
1335 }
1336 if (!found) {
1337 debug("No more client hostkeys for hostbased authentication.");
1338 return 0;
1339 }
1340 if (key_to_blob(private, &blob, &blen) == 0) {
1341 key_free(private);
1342 return 0;
1343 }
1344 /* figure out a name for the client host */
1345 p = NULL;
1346 if (packet_connection_is_on_socket())
1347 p = get_local_name(packet_get_connection_in());
1348 if (p == NULL) {
1349 if (gethostname(myname, sizeof(myname)) == -1) {
1350 verbose("userauth_hostbased: gethostname: %s",
1351 strerror(errno));
1352 } else
1353 p = xstrdup(myname);
1354 }
1355 if (p == NULL) {
1356 error("userauth_hostbased: cannot get local ipaddr/name");
1357 key_free(private);
1358 xfree(blob);
1359 return 0;
1360 }
1361 len = strlen(p) + 2;
1362 xasprintf(&chost, "%s.", p);
1363 debug2("userauth_hostbased: chost %s", chost);
1364 xfree(p);
1365
1366 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1367 authctxt->service;
1368 pkalg = xstrdup(key_ssh_name(private));
1369 buffer_init(&b);
1370 /* construct data */
1371 buffer_put_string(&b, session_id2, session_id2_len);
1372 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1373 buffer_put_cstring(&b, authctxt->server_user);
1374 buffer_put_cstring(&b, service);
1375 buffer_put_cstring(&b, authctxt->method->name);
1376 buffer_put_cstring(&b, pkalg);
1377 buffer_put_string(&b, blob, blen);
1378 buffer_put_cstring(&b, chost);
1379 buffer_put_cstring(&b, authctxt->local_user);
1380#ifdef DEBUG_PK
1381 buffer_dump(&b);
1382#endif
1383 if (sensitive->external_keysign)
1384 ok = ssh_keysign(private, &signature, &slen,
1385 buffer_ptr(&b), buffer_len(&b));
1386 else
1387 ok = key_sign(private, &signature, &slen,
1388 buffer_ptr(&b), buffer_len(&b));
1389 key_free(private);
1390 buffer_free(&b);
1391 if (ok != 0) {
1392 error("key_sign failed");
1393 xfree(chost);
1394 xfree(pkalg);
1395 xfree(blob);
1396 return 0;
1397 }
1398 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1399 packet_put_cstring(authctxt->server_user);
1400 packet_put_cstring(authctxt->service);
1401 packet_put_cstring(authctxt->method->name);
1402 packet_put_cstring(pkalg);
1403 packet_put_string(blob, blen);
1404 packet_put_cstring(chost);
1405 packet_put_cstring(authctxt->local_user);
1406 packet_put_string(signature, slen);
1407 memset(signature, 's', slen);
1408 xfree(signature);
1409 xfree(chost);
1410 xfree(pkalg);
1411 xfree(blob);
1412
1413 packet_send();
1414 return 1;
1415}
1416
1417/* find auth method */
1418
1419/*
1420 * given auth method name, if configurable options permit this method fill
1421 * in auth_ident field and return true, otherwise return false.
1422 */
1423static int
1424authmethod_is_enabled(Authmethod *method)
1425{
1426 if (method == NULL)
1427 return 0;
1428 /* return false if options indicate this method is disabled */
1429 if (method->enabled == NULL || *method->enabled == 0)
1430 return 0;
1431 /* return false if batch mode is enabled but method needs interactive mode */
1432 if (method->batch_flag != NULL && *method->batch_flag != 0)
1433 return 0;
1434 return 1;
1435}
1436
1437static Authmethod *
1438authmethod_lookup(const char *name)
1439{
1440 Authmethod *method = NULL;
1441 if (name != NULL)
1442 for (method = authmethods; method->name != NULL; method++)
1443 if (strcmp(name, method->name) == 0)
1444 return method;
1445 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1446 return NULL;
1447}
1448
1449/* XXX internal state */
1450static Authmethod *current = NULL;
1451static char *supported = NULL;
1452static char *preferred = NULL;
1453
1454/*
1455 * Given the authentication method list sent by the server, return the
1456 * next method we should try. If the server initially sends a nil list,
1457 * use a built-in default list.
1458 */
1459static Authmethod *
1460authmethod_get(char *authlist)
1461{
1462 char *name = NULL;
1463 u_int next;
1464
1465 /* Use a suitable default if we're passed a nil list. */
1466 if (authlist == NULL || strlen(authlist) == 0)
1467 authlist = options.preferred_authentications;
1468
1469 if (supported == NULL || strcmp(authlist, supported) != 0) {
1470 debug3("start over, passed a different list %s", authlist);
1471 if (supported != NULL)
1472 xfree(supported);
1473 supported = xstrdup(authlist);
1474 preferred = options.preferred_authentications;
1475 debug3("preferred %s", preferred);
1476 current = NULL;
1477 } else if (current != NULL && authmethod_is_enabled(current))
1478 return current;
1479
1480 for (;;) {
1481 if ((name = match_list(preferred, supported, &next)) == NULL) {
1482 debug("No more authentication methods to try.");
1483 current = NULL;
1484 return NULL;
1485 }
1486 preferred += next;
1487 debug3("authmethod_lookup %s", name);
1488 debug3("remaining preferred: %s", preferred);
1489 if ((current = authmethod_lookup(name)) != NULL &&
1490 authmethod_is_enabled(current)) {
1491 debug3("authmethod_is_enabled %s", name);
1492 debug("Next authentication method: %s", name);
1493 return current;
1494 }
1495 }
1496}
1497
1498static char *
1499authmethods_get(void)
1500{
1501 Authmethod *method = NULL;
1502 Buffer b;
1503 char *list;
1504
1505 buffer_init(&b);
1506 for (method = authmethods; method->name != NULL; method++) {
1507 if (authmethod_is_enabled(method)) {
1508 if (buffer_len(&b) > 0)
1509 buffer_append(&b, ",", 1);
1510 buffer_append(&b, method->name, strlen(method->name));
1511 }
1512 }
1513 buffer_append(&b, "\0", 1);
1514 list = xstrdup(buffer_ptr(&b));
1515 buffer_free(&b);
1516 return list;
1517}