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[gssapi-openssh.git] / openssh / sshconnect2.c
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91d9cdd3 1/* $OpenBSD: sshconnect2.c,v 1.170 2008/11/04 08:22:13 djm Exp $ */
3c0ef626 2/*
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
91d9cdd3 4 * Copyright (c) 2008 Damien Miller. All rights reserved.
3c0ef626 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"
9108f8d9 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>
d4487008 35#include <netdb.h>
9108f8d9 36#include <pwd.h>
37#include <signal.h>
38#include <stdarg.h>
39#include <stdio.h>
40#include <string.h>
41#include <unistd.h>
22616013 42#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H)
43#include <vis.h>
44#endif
0fff78ff 45
46#include "openbsd-compat/sys-queue.h"
3c0ef626 47
9108f8d9 48#include "xmalloc.h"
3c0ef626 49#include "ssh.h"
50#include "ssh2.h"
3c0ef626 51#include "buffer.h"
52#include "packet.h"
3c0ef626 53#include "compat.h"
3c0ef626 54#include "cipher.h"
9108f8d9 55#include "key.h"
3c0ef626 56#include "kex.h"
57#include "myproposal.h"
3c0ef626 58#include "sshconnect.h"
59#include "authfile.h"
60#include "dh.h"
61#include "authfd.h"
62#include "log.h"
63#include "readconf.h"
c9f39d2c 64#include "misc.h"
3c0ef626 65#include "match.h"
66#include "dispatch.h"
67#include "canohost.h"
f5799ae1 68#include "msg.h"
69#include "pathnames.h"
9108f8d9 70#include "uidswap.h"
91d9cdd3 71#include "jpake.h"
3c0ef626 72
0fff78ff 73#ifdef GSSAPI
74#include "ssh-gss.h"
75#endif
76
3c0ef626 77/* import */
78extern char *client_version_string;
79extern char *server_version_string;
80extern Options options;
81
82/*
83 * SSH2 key exchange
84 */
85
86u_char *session_id2 = NULL;
0fff78ff 87u_int session_id2_len = 0;
3c0ef626 88
89char *xxx_host;
90struct sockaddr *xxx_hostaddr;
91
92Kex *xxx_kex = NULL;
93
94static int
95verify_host_key_callback(Key *hostkey)
96{
97 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
98 fatal("Host key verification failed.");
99 return 0;
100}
101
102void
103ssh_kex2(char *host, struct sockaddr *hostaddr)
104{
105 Kex *kex;
106
f97edba6 107#ifdef GSSAPI
108 char *orig = NULL, *gss = NULL;
109 char *gss_host = NULL;
110#endif
111
3c0ef626 112 xxx_host = host;
113 xxx_hostaddr = hostaddr;
114
f97edba6 115#ifdef GSSAPI
116 if (options.gss_keyex) {
117 /* Add the GSSAPI mechanisms currently supported on this
118 * client to the key exchange algorithm proposal */
119 orig = myproposal[PROPOSAL_KEX_ALGS];
120
121 if (options.gss_trust_dns)
122 gss_host = (char *)get_canonical_hostname(1);
123 else
124 gss_host = host;
125
126 gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity);
127 if (gss) {
128 debug("Offering GSSAPI proposal: %s", gss);
129 xasprintf(&myproposal[PROPOSAL_KEX_ALGS],
130 "%s,%s", gss, orig);
131 }
132 }
133#endif
134
3c0ef626 135 if (options.ciphers == (char *)-1) {
0fff78ff 136 logit("No valid ciphers for protocol version 2 given, using defaults.");
3c0ef626 137 options.ciphers = NULL;
138 }
139 if (options.ciphers != NULL) {
140 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
141 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
142 }
143 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
144 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
145 myproposal[PROPOSAL_ENC_ALGS_STOC] =
146 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
147 if (options.compression) {
148 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
665a873d 149 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
3c0ef626 150 } else {
151 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
665a873d 152 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
3c0ef626 153 }
154 if (options.macs != NULL) {
155 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
156 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
157 }
158 if (options.hostkeyalgorithms != NULL)
e9a17296 159 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
3c0ef626 160 options.hostkeyalgorithms;
161
f97edba6 162#ifdef GSSAPI
163 /* If we've got GSSAPI algorithms, then we also support the
164 * 'null' hostkey, as a last resort */
165 if (options.gss_keyex && gss) {
166 orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
167 xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],
168 "%s,null", orig);
169 xfree(gss);
170 }
171#endif
172
0fff78ff 173 if (options.rekey_limit)
47686178 174 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
0fff78ff 175
3c0ef626 176 /* start key exchange */
177 kex = kex_setup(myproposal);
6a9b3198 178 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
c9f39d2c 179 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
6a9b3198 180 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
9108f8d9 181 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
f97edba6 182#ifdef GSSAPI
183 if (options.gss_keyex) {
184 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
185 kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client;
186 kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client;
187 }
188#endif
3c0ef626 189 kex->client_version_string=client_version_string;
190 kex->server_version_string=server_version_string;
191 kex->verify_host_key=&verify_host_key_callback;
192
f97edba6 193#ifdef GSSAPI
194 if (options.gss_keyex) {
195 kex->gss_deleg_creds = options.gss_deleg_creds;
196 kex->gss_trust_dns = options.gss_trust_dns;
197 kex->gss_client = options.gss_client_identity;
198 kex->gss_host = gss_host;
199 }
200#endif
201
3c0ef626 202 xxx_kex = kex;
203
204 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
205
206 session_id2 = kex->session_id;
207 session_id2_len = kex->session_id_len;
208
209#ifdef DEBUG_KEXDH
210 /* send 1st encrypted/maced/compressed message */
211 packet_start(SSH2_MSG_IGNORE);
212 packet_put_cstring("markus");
213 packet_send();
214 packet_write_wait();
215#endif
3c0ef626 216}
217
218/*
219 * Authenticate user
220 */
221
222typedef struct Authctxt Authctxt;
223typedef struct Authmethod Authmethod;
0fff78ff 224typedef struct identity Identity;
225typedef struct idlist Idlist;
226
227struct identity {
228 TAILQ_ENTRY(identity) next;
229 AuthenticationConnection *ac; /* set if agent supports key */
230 Key *key; /* public/private key */
231 char *filename; /* comment for agent-only keys */
232 int tried;
233 int isprivate; /* key points to the private key */
234};
235TAILQ_HEAD(idlist, identity);
3c0ef626 236
237struct Authctxt {
238 const char *server_user;
239 const char *local_user;
240 const char *host;
241 const char *service;
242 Authmethod *method;
243 int success;
244 char *authlist;
245 /* pubkey */
0fff78ff 246 Idlist keys;
3c0ef626 247 AuthenticationConnection *agent;
248 /* hostbased */
f5799ae1 249 Sensitive *sensitive;
3c0ef626 250 /* kbd-interactive */
251 int info_req_seen;
0fff78ff 252 /* generic */
253 void *methoddata;
3c0ef626 254};
255struct Authmethod {
256 char *name; /* string to compare against server's list */
257 int (*userauth)(Authctxt *authctxt);
91d9cdd3 258 void (*cleanup)(Authctxt *authctxt);
3c0ef626 259 int *enabled; /* flag in option struct that enables method */
260 int *batch_flag; /* flag in option struct that disables method */
261};
262
e9a17296 263void input_userauth_success(int, u_int32_t, void *);
264void input_userauth_failure(int, u_int32_t, void *);
265void input_userauth_banner(int, u_int32_t, void *);
266void input_userauth_error(int, u_int32_t, void *);
267void input_userauth_info_req(int, u_int32_t, void *);
268void input_userauth_pk_ok(int, u_int32_t, void *);
700318f3 269void input_userauth_passwd_changereq(int, u_int32_t, void *);
91d9cdd3 270void input_userauth_jpake_server_step1(int, u_int32_t, void *);
271void input_userauth_jpake_server_step2(int, u_int32_t, void *);
272void input_userauth_jpake_server_confirm(int, u_int32_t, void *);
3c0ef626 273
e9a17296 274int userauth_none(Authctxt *);
275int userauth_pubkey(Authctxt *);
276int userauth_passwd(Authctxt *);
277int userauth_kbdint(Authctxt *);
278int userauth_hostbased(Authctxt *);
91d9cdd3 279int userauth_jpake(Authctxt *);
280
281void userauth_jpake_cleanup(Authctxt *);
0fff78ff 282
283#ifdef GSSAPI
284int userauth_gssapi(Authctxt *authctxt);
285void input_gssapi_response(int type, u_int32_t, void *);
286void input_gssapi_token(int type, u_int32_t, void *);
287void input_gssapi_hash(int type, u_int32_t, void *);
288void input_gssapi_error(int, u_int32_t, void *);
289void input_gssapi_errtok(int, u_int32_t, void *);
f97edba6 290int userauth_gsskeyex(Authctxt *authctxt);
0fff78ff 291#endif
3c0ef626 292
e9a17296 293void userauth(Authctxt *, char *);
3c0ef626 294
0fff78ff 295static int sign_and_send_pubkey(Authctxt *, Identity *);
296static void pubkey_prepare(Authctxt *);
297static void pubkey_cleanup(Authctxt *);
298static Key *load_identity_file(char *);
3c0ef626 299
300static Authmethod *authmethod_get(char *authlist);
301static Authmethod *authmethod_lookup(const char *name);
302static char *authmethods_get(void);
303
304Authmethod authmethods[] = {
0fff78ff 305#ifdef GSSAPI
f97edba6 306 {"gssapi-keyex",
307 userauth_gsskeyex,
308 &options.gss_authentication,
309 NULL},
cdd66111 310 {"gssapi-with-mic",
0fff78ff 311 userauth_gssapi,
91d9cdd3 312 NULL,
0fff78ff 313 &options.gss_authentication,
314 NULL},
315#endif
3c0ef626 316 {"hostbased",
317 userauth_hostbased,
91d9cdd3 318 NULL,
3c0ef626 319 &options.hostbased_authentication,
320 NULL},
321 {"publickey",
322 userauth_pubkey,
91d9cdd3 323 NULL,
3c0ef626 324 &options.pubkey_authentication,
325 NULL},
91d9cdd3 326#ifdef JPAKE
327 {"jpake-01@openssh.com",
328 userauth_jpake,
329 userauth_jpake_cleanup,
330 &options.zero_knowledge_password_authentication,
331 &options.batch_mode},
332#endif
3c0ef626 333 {"keyboard-interactive",
334 userauth_kbdint,
91d9cdd3 335 NULL,
3c0ef626 336 &options.kbd_interactive_authentication,
337 &options.batch_mode},
338 {"password",
339 userauth_passwd,
91d9cdd3 340 NULL,
3c0ef626 341 &options.password_authentication,
342 &options.batch_mode},
343 {"none",
344 userauth_none,
345 NULL,
91d9cdd3 346 NULL,
3c0ef626 347 NULL},
91d9cdd3 348 {NULL, NULL, NULL, NULL, NULL}
3c0ef626 349};
350
351void
352ssh_userauth2(const char *local_user, const char *server_user, char *host,
f5799ae1 353 Sensitive *sensitive)
3c0ef626 354{
355 Authctxt authctxt;
356 int type;
3c0ef626 357
358 if (options.challenge_response_authentication)
359 options.kbd_interactive_authentication = 1;
360
3c0ef626 361 packet_start(SSH2_MSG_SERVICE_REQUEST);
362 packet_put_cstring("ssh-userauth");
363 packet_send();
6a9b3198 364 debug("SSH2_MSG_SERVICE_REQUEST sent");
3c0ef626 365 packet_write_wait();
e9a17296 366 type = packet_read();
6a9b3198 367 if (type != SSH2_MSG_SERVICE_ACCEPT)
368 fatal("Server denied authentication request: %d", type);
3c0ef626 369 if (packet_remaining() > 0) {
e9a17296 370 char *reply = packet_get_string(NULL);
6a9b3198 371 debug2("service_accept: %s", reply);
3c0ef626 372 xfree(reply);
373 } else {
6a9b3198 374 debug2("buggy server: service_accept w/o service");
3c0ef626 375 }
e9a17296 376 packet_check_eom();
6a9b3198 377 debug("SSH2_MSG_SERVICE_ACCEPT received");
3c0ef626 378
379 if (options.preferred_authentications == NULL)
380 options.preferred_authentications = authmethods_get();
381
382 /* setup authentication context */
383 memset(&authctxt, 0, sizeof(authctxt));
0fff78ff 384 pubkey_prepare(&authctxt);
3c0ef626 385 authctxt.server_user = server_user;
386 authctxt.local_user = local_user;
387 authctxt.host = host;
388 authctxt.service = "ssh-connection"; /* service name */
389 authctxt.success = 0;
390 authctxt.method = authmethod_lookup("none");
391 authctxt.authlist = NULL;
0fff78ff 392 authctxt.methoddata = NULL;
f5799ae1 393 authctxt.sensitive = sensitive;
3c0ef626 394 authctxt.info_req_seen = 0;
395 if (authctxt.method == NULL)
396 fatal("ssh_userauth2: internal error: cannot send userauth none request");
397
398 /* initial userauth request */
399 userauth_none(&authctxt);
400
401 dispatch_init(&input_userauth_error);
402 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
403 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
404 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
405 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
406
0fff78ff 407 pubkey_cleanup(&authctxt);
408 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
3c0ef626 409
6a9b3198 410 debug("Authentication succeeded (%s).", authctxt.method->name);
3c0ef626 411}
0fff78ff 412
3c0ef626 413void
414userauth(Authctxt *authctxt, char *authlist)
415{
91d9cdd3 416 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
417 authctxt->method->cleanup(authctxt);
418
0fff78ff 419 if (authctxt->methoddata) {
420 xfree(authctxt->methoddata);
421 authctxt->methoddata = NULL;
422 }
3c0ef626 423 if (authlist == NULL) {
424 authlist = authctxt->authlist;
425 } else {
426 if (authctxt->authlist)
427 xfree(authctxt->authlist);
428 authctxt->authlist = authlist;
429 }
430 for (;;) {
431 Authmethod *method = authmethod_get(authlist);
432 if (method == NULL)
433 fatal("Permission denied (%s).", authlist);
434 authctxt->method = method;
0fff78ff 435
436 /* reset the per method handler */
437 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
438 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
439
440 /* and try new method */
3c0ef626 441 if (method->userauth(authctxt) != 0) {
442 debug2("we sent a %s packet, wait for reply", method->name);
443 break;
444 } else {
445 debug2("we did not send a packet, disable method");
446 method->enabled = NULL;
447 }
448 }
449}
680cee3b 450
91d9cdd3 451/* ARGSUSED */
3c0ef626 452void
e9a17296 453input_userauth_error(int type, u_int32_t seq, void *ctxt)
3c0ef626 454{
455 fatal("input_userauth_error: bad message during authentication: "
665a873d 456 "type %d", type);
3c0ef626 457}
680cee3b 458
91d9cdd3 459/* ARGSUSED */
3c0ef626 460void
e9a17296 461input_userauth_banner(int type, u_int32_t seq, void *ctxt)
3c0ef626 462{
22616013 463 char *msg, *raw, *lang;
464 u_int len;
cdd66111 465
3c0ef626 466 debug3("input_userauth_banner");
22616013 467 raw = packet_get_string(&len);
3c0ef626 468 lang = packet_get_string(NULL);
91d9cdd3 469 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
22616013 470 if (len > 65536)
471 len = 65536;
91d9cdd3 472 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
473 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL);
cdd66111 474 fprintf(stderr, "%s", msg);
22616013 475 xfree(msg);
476 }
477 xfree(raw);
3c0ef626 478 xfree(lang);
479}
680cee3b 480
91d9cdd3 481/* ARGSUSED */
3c0ef626 482void
e9a17296 483input_userauth_success(int type, u_int32_t seq, void *ctxt)
3c0ef626 484{
485 Authctxt *authctxt = ctxt;
486 if (authctxt == NULL)
487 fatal("input_userauth_success: no authentication context");
cdd66111 488 if (authctxt->authlist) {
3c0ef626 489 xfree(authctxt->authlist);
cdd66111 490 authctxt->authlist = NULL;
491 }
492 if (authctxt->methoddata) {
0fff78ff 493 xfree(authctxt->methoddata);
cdd66111 494 authctxt->methoddata = NULL;
495 }
3c0ef626 496 authctxt->success = 1; /* break out */
497}
680cee3b 498
91d9cdd3 499/* ARGSUSED */
3c0ef626 500void
e9a17296 501input_userauth_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 502{
503 Authctxt *authctxt = ctxt;
504 char *authlist = NULL;
505 int partial;
506
507 if (authctxt == NULL)
508 fatal("input_userauth_failure: no authentication context");
509
510 authlist = packet_get_string(NULL);
511 partial = packet_get_char();
e9a17296 512 packet_check_eom();
3c0ef626 513
514 if (partial != 0)
0fff78ff 515 logit("Authenticated with partial success.");
6a9b3198 516 debug("Authentications that can continue: %s", authlist);
3c0ef626 517
3c0ef626 518 userauth(authctxt, authlist);
519}
91d9cdd3 520
521/* ARGSUSED */
3c0ef626 522void
e9a17296 523input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
3c0ef626 524{
525 Authctxt *authctxt = ctxt;
526 Key *key = NULL;
0fff78ff 527 Identity *id = NULL;
3c0ef626 528 Buffer b;
e9a17296 529 int pktype, sent = 0;
530 u_int alen, blen;
531 char *pkalg, *fp;
532 u_char *pkblob;
3c0ef626 533
534 if (authctxt == NULL)
535 fatal("input_userauth_pk_ok: no authentication context");
536 if (datafellows & SSH_BUG_PKOK) {
537 /* this is similar to SSH_BUG_PKAUTH */
538 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
539 pkblob = packet_get_string(&blen);
540 buffer_init(&b);
541 buffer_append(&b, pkblob, blen);
542 pkalg = buffer_get_string(&b, &alen);
543 buffer_free(&b);
544 } else {
545 pkalg = packet_get_string(&alen);
546 pkblob = packet_get_string(&blen);
547 }
e9a17296 548 packet_check_eom();
3c0ef626 549
0fff78ff 550 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
3c0ef626 551
0fff78ff 552 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
553 debug("unknown pkalg %s", pkalg);
554 goto done;
555 }
556 if ((key = key_from_blob(pkblob, blen)) == NULL) {
557 debug("no key from blob. pkalg %s", pkalg);
558 goto done;
559 }
560 if (key->type != pktype) {
561 error("input_userauth_pk_ok: type mismatch "
562 "for decoded key (received %d, expected %d)",
563 key->type, pktype);
564 goto done;
565 }
566 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
567 debug2("input_userauth_pk_ok: fp %s", fp);
568 xfree(fp);
569
cdd66111 570 /*
571 * search keys in the reverse order, because last candidate has been
572 * moved to the end of the queue. this also avoids confusion by
573 * duplicate keys
574 */
c9f39d2c 575 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
0fff78ff 576 if (key_equal(key, id->key)) {
577 sent = sign_and_send_pubkey(authctxt, id);
3c0ef626 578 break;
579 }
0fff78ff 580 }
581done:
3c0ef626 582 if (key != NULL)
583 key_free(key);
584 xfree(pkalg);
585 xfree(pkblob);
586
41b2f314 587 /* try another method if we did not send a packet */
3c0ef626 588 if (sent == 0)
589 userauth(authctxt, NULL);
0fff78ff 590}
591
592#ifdef GSSAPI
cdd66111 593int
0fff78ff 594userauth_gssapi(Authctxt *authctxt)
595{
596 Gssctxt *gssctxt = NULL;
cdd66111 597 static gss_OID_set gss_supported = NULL;
665a873d 598 static u_int mech = 0;
0fff78ff 599 OM_uint32 min;
600 int ok = 0;
f97edba6 601 const char *gss_host;
602
603 if (options.gss_trust_dns)
604 gss_host = get_canonical_hostname(1);
605 else
606 gss_host = authctxt->host;
0fff78ff 607
608 /* Try one GSSAPI method at a time, rather than sending them all at
609 * once. */
610
cdd66111 611 if (gss_supported == NULL)
f97edba6 612 if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) {
613 gss_supported = NULL;
614 return 0;
615 }
0fff78ff 616
617 /* Check to see if the mechanism is usable before we offer it */
cdd66111 618 while (mech < gss_supported->count && !ok) {
0fff78ff 619 /* My DER encoding requires length<128 */
cdd66111 620 if (gss_supported->elements[mech].length < 128 &&
9108f8d9 621 ssh_gssapi_check_mechanism(&gssctxt,
f97edba6 622 &gss_supported->elements[mech], gss_host,
623 options.gss_client_identity)) {
0fff78ff 624 ok = 1; /* Mechanism works */
625 } else {
626 mech++;
627 }
628 }
629
665a873d 630 if (!ok)
631 return 0;
0fff78ff 632
633 authctxt->methoddata=(void *)gssctxt;
634
635 packet_start(SSH2_MSG_USERAUTH_REQUEST);
636 packet_put_cstring(authctxt->server_user);
637 packet_put_cstring(authctxt->service);
638 packet_put_cstring(authctxt->method->name);
639
640 packet_put_int(1);
641
cdd66111 642 packet_put_int((gss_supported->elements[mech].length) + 2);
643 packet_put_char(SSH_GSS_OIDTYPE);
644 packet_put_char(gss_supported->elements[mech].length);
645 packet_put_raw(gss_supported->elements[mech].elements,
646 gss_supported->elements[mech].length);
0fff78ff 647
648 packet_send();
649
650 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
651 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
652 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
653 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
654
655 mech++; /* Move along to next candidate */
656
657 return 1;
658}
659
cdd66111 660static OM_uint32
661process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
662{
663 Authctxt *authctxt = ctxt;
664 Gssctxt *gssctxt = authctxt->methoddata;
665 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
665a873d 666 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
667 gss_buffer_desc gssbuf;
cdd66111 668 OM_uint32 status, ms, flags;
669 Buffer b;
670
671 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
672 recv_tok, &send_tok, &flags);
673
674 if (send_tok.length > 0) {
675 if (GSS_ERROR(status))
676 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
677 else
678 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
679
680 packet_put_string(send_tok.value, send_tok.length);
681 packet_send();
682 gss_release_buffer(&ms, &send_tok);
683 }
684
685 if (status == GSS_S_COMPLETE) {
686 /* send either complete or MIC, depending on mechanism */
687 if (!(flags & GSS_C_INTEG_FLAG)) {
688 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
689 packet_send();
690 } else {
691 ssh_gssapi_buildmic(&b, authctxt->server_user,
692 authctxt->service, "gssapi-with-mic");
693
694 gssbuf.value = buffer_ptr(&b);
695 gssbuf.length = buffer_len(&b);
696
697 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
698
699 if (!GSS_ERROR(status)) {
700 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
701 packet_put_string(mic.value, mic.length);
702
703 packet_send();
704 }
705
706 buffer_free(&b);
707 gss_release_buffer(&ms, &mic);
708 }
709 }
710
711 return status;
712}
713
91d9cdd3 714/* ARGSUSED */
0fff78ff 715void
716input_gssapi_response(int type, u_int32_t plen, void *ctxt)
717{
718 Authctxt *authctxt = ctxt;
719 Gssctxt *gssctxt;
f97edba6 720 u_int oidlen;
721 u_char *oidv;
0fff78ff 722
723 if (authctxt == NULL)
724 fatal("input_gssapi_response: no authentication context");
725 gssctxt = authctxt->methoddata;
726
727 /* Setup our OID */
728 oidv = packet_get_string(&oidlen);
729
cdd66111 730 if (oidlen <= 2 ||
731 oidv[0] != SSH_GSS_OIDTYPE ||
732 oidv[1] != oidlen - 2) {
733 xfree(oidv);
734 debug("Badly encoded mechanism OID received");
735 userauth(authctxt, NULL);
736 return;
0fff78ff 737 }
738
cdd66111 739 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
740 fatal("Server returned different OID than expected");
741
0fff78ff 742 packet_check_eom();
743
744 xfree(oidv);
745
cdd66111 746 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
0fff78ff 747 /* Start again with next method on list */
748 debug("Trying to start again");
749 userauth(authctxt, NULL);
750 return;
751 }
0fff78ff 752}
753
91d9cdd3 754/* ARGSUSED */
0fff78ff 755void
756input_gssapi_token(int type, u_int32_t plen, void *ctxt)
757{
758 Authctxt *authctxt = ctxt;
0fff78ff 759 gss_buffer_desc recv_tok;
cdd66111 760 OM_uint32 status;
0fff78ff 761 u_int slen;
762
763 if (authctxt == NULL)
764 fatal("input_gssapi_response: no authentication context");
0fff78ff 765
766 recv_tok.value = packet_get_string(&slen);
767 recv_tok.length = slen; /* safe typecast */
768
769 packet_check_eom();
770
cdd66111 771 status = process_gssapi_token(ctxt, &recv_tok);
0fff78ff 772
773 xfree(recv_tok.value);
774
775 if (GSS_ERROR(status)) {
0fff78ff 776 /* Start again with the next method in the list */
777 userauth(authctxt, NULL);
778 return;
779 }
3c0ef626 780}
781
91d9cdd3 782/* ARGSUSED */
0fff78ff 783void
784input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
785{
786 Authctxt *authctxt = ctxt;
787 Gssctxt *gssctxt;
788 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
789 gss_buffer_desc recv_tok;
790 OM_uint32 status, ms;
791 u_int len;
792
793 if (authctxt == NULL)
794 fatal("input_gssapi_response: no authentication context");
795 gssctxt = authctxt->methoddata;
796
797 recv_tok.value = packet_get_string(&len);
798 recv_tok.length = len;
799
800 packet_check_eom();
801
802 /* Stick it into GSSAPI and see what it says */
803 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
665a873d 804 &recv_tok, &send_tok, NULL);
0fff78ff 805
806 xfree(recv_tok.value);
807 gss_release_buffer(&ms, &send_tok);
808
809 /* Server will be returning a failed packet after this one */
810}
811
91d9cdd3 812/* ARGSUSED */
0fff78ff 813void
814input_gssapi_error(int type, u_int32_t plen, void *ctxt)
815{
816 OM_uint32 maj, min;
817 char *msg;
818 char *lang;
819
820 maj=packet_get_int();
821 min=packet_get_int();
822 msg=packet_get_string(NULL);
823 lang=packet_get_string(NULL);
824
825 packet_check_eom();
826
2c06c99b 827 debug("Server GSSAPI Error:\n%s", msg);
0fff78ff 828 xfree(msg);
829 xfree(lang);
830}
f97edba6 831
832int
833userauth_gsskeyex(Authctxt *authctxt)
834{
835 Buffer b;
836 gss_buffer_desc gssbuf;
837 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
838 OM_uint32 ms;
839
840 static int attempt = 0;
841 if (attempt++ >= 1)
842 return (0);
843
844 if (gss_kex_context == NULL) {
845 debug("No valid Key exchange context");
846 return (0);
847 }
848
849 ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service,
850 "gssapi-keyex");
851
852 gssbuf.value = buffer_ptr(&b);
853 gssbuf.length = buffer_len(&b);
854
855 if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) {
856 buffer_free(&b);
857 return (0);
858 }
859
860 packet_start(SSH2_MSG_USERAUTH_REQUEST);
861 packet_put_cstring(authctxt->server_user);
862 packet_put_cstring(authctxt->service);
863 packet_put_cstring(authctxt->method->name);
864 packet_put_string(mic.value, mic.length);
865 packet_send();
866
867 buffer_free(&b);
868 gss_release_buffer(&ms, &mic);
869
870 return (1);
871}
872
0fff78ff 873#endif /* GSSAPI */
874
3c0ef626 875int
876userauth_none(Authctxt *authctxt)
877{
878 /* initial userauth request */
879 packet_start(SSH2_MSG_USERAUTH_REQUEST);
880 packet_put_cstring(authctxt->server_user);
881 packet_put_cstring(authctxt->service);
882 packet_put_cstring(authctxt->method->name);
883 packet_send();
884 return 1;
885}
886
887int
888userauth_passwd(Authctxt *authctxt)
889{
890 static int attempt = 0;
700318f3 891 char prompt[150];
3c0ef626 892 char *password;
893
894 if (attempt++ >= options.number_of_password_prompts)
895 return 0;
896
e9a17296 897 if (attempt != 1)
3c0ef626 898 error("Permission denied, please try again.");
899
900 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
901 authctxt->server_user, authctxt->host);
902 password = read_passphrase(prompt, 0);
903 packet_start(SSH2_MSG_USERAUTH_REQUEST);
904 packet_put_cstring(authctxt->server_user);
905 packet_put_cstring(authctxt->service);
906 packet_put_cstring(authctxt->method->name);
907 packet_put_char(0);
908 packet_put_cstring(password);
909 memset(password, 0, strlen(password));
910 xfree(password);
911 packet_add_padding(64);
912 packet_send();
700318f3 913
f5799ae1 914 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
700318f3 915 &input_userauth_passwd_changereq);
916
3c0ef626 917 return 1;
918}
91d9cdd3 919
700318f3 920/*
921 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
922 */
91d9cdd3 923/* ARGSUSED */
700318f3 924void
925input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
926{
927 Authctxt *authctxt = ctxt;
928 char *info, *lang, *password = NULL, *retype = NULL;
929 char prompt[150];
930
931 debug2("input_userauth_passwd_changereq");
932
933 if (authctxt == NULL)
934 fatal("input_userauth_passwd_changereq: "
935 "no authentication context");
936
937 info = packet_get_string(NULL);
938 lang = packet_get_string(NULL);
939 if (strlen(info) > 0)
0fff78ff 940 logit("%s", info);
700318f3 941 xfree(info);
942 xfree(lang);
943 packet_start(SSH2_MSG_USERAUTH_REQUEST);
944 packet_put_cstring(authctxt->server_user);
945 packet_put_cstring(authctxt->service);
946 packet_put_cstring(authctxt->method->name);
947 packet_put_char(1); /* additional info */
f5799ae1 948 snprintf(prompt, sizeof(prompt),
700318f3 949 "Enter %.30s@%.128s's old password: ",
950 authctxt->server_user, authctxt->host);
951 password = read_passphrase(prompt, 0);
952 packet_put_cstring(password);
953 memset(password, 0, strlen(password));
954 xfree(password);
955 password = NULL;
956 while (password == NULL) {
f5799ae1 957 snprintf(prompt, sizeof(prompt),
700318f3 958 "Enter %.30s@%.128s's new password: ",
959 authctxt->server_user, authctxt->host);
960 password = read_passphrase(prompt, RP_ALLOW_EOF);
961 if (password == NULL) {
962 /* bail out */
963 return;
964 }
f5799ae1 965 snprintf(prompt, sizeof(prompt),
700318f3 966 "Retype %.30s@%.128s's new password: ",
967 authctxt->server_user, authctxt->host);
968 retype = read_passphrase(prompt, 0);
969 if (strcmp(password, retype) != 0) {
970 memset(password, 0, strlen(password));
971 xfree(password);
0fff78ff 972 logit("Mismatch; try again, EOF to quit.");
700318f3 973 password = NULL;
974 }
975 memset(retype, 0, strlen(retype));
976 xfree(retype);
977 }
978 packet_put_cstring(password);
979 memset(password, 0, strlen(password));
980 xfree(password);
981 packet_add_padding(64);
982 packet_send();
f5799ae1 983
984 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
700318f3 985 &input_userauth_passwd_changereq);
986}
3c0ef626 987
91d9cdd3 988#ifdef JPAKE
989static char *
990pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
991{
992 /* OpenBSD crypt(3) handles all of these */
993 if (strcmp(crypt_scheme, "crypt") == 0 ||
994 strcmp(crypt_scheme, "bcrypt") == 0 ||
995 strcmp(crypt_scheme, "md5crypt") == 0 ||
996 strcmp(crypt_scheme, "crypt-extended") == 0)
997 return xstrdup(crypt(password, salt));
998 error("%s: unsupported password encryption scheme \"%.100s\"",
999 __func__, crypt_scheme);
1000 return NULL;
1001}
1002
1003static BIGNUM *
1004jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
1005 const char *salt)
1006{
1007 char prompt[256], *password, *crypted;
1008 u_char *secret;
1009 u_int secret_len;
1010 BIGNUM *ret;
1011
1012 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
1013 authctxt->server_user, authctxt->host);
1014 password = read_passphrase(prompt, 0);
1015
1016 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
1017 logit("Disabling %s authentication", authctxt->method->name);
1018 authctxt->method->enabled = NULL;
1019 /* Continue with an empty password to fail gracefully */
1020 crypted = xstrdup("");
1021 }
1022
1023#ifdef JPAKE_DEBUG
1024 debug3("%s: salt = %s", __func__, salt);
1025 debug3("%s: scheme = %s", __func__, crypt_scheme);
1026 debug3("%s: crypted = %s", __func__, crypted);
1027#endif
1028
1029 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(),
1030 &secret, &secret_len) != 0)
1031 fatal("%s: hash_buffer", __func__);
1032
1033 bzero(password, strlen(password));
1034 bzero(crypted, strlen(crypted));
1035 xfree(password);
1036 xfree(crypted);
1037
1038 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
1039 fatal("%s: BN_bin2bn (secret)", __func__);
1040 bzero(secret, secret_len);
1041 xfree(secret);
1042
1043 return ret;
1044}
1045
1046/* ARGSUSED */
1047void
1048input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
1049{
1050 Authctxt *authctxt = ctxt;
1051 struct jpake_ctx *pctx = authctxt->methoddata;
1052 u_char *x3_proof, *x4_proof, *x2_s_proof;
1053 u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
1054 char *crypt_scheme, *salt;
1055
1056 /* Disable this message */
1057 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
1058
1059 if ((pctx->g_x3 = BN_new()) == NULL ||
1060 (pctx->g_x4 = BN_new()) == NULL)
1061 fatal("%s: BN_new", __func__);
1062
1063 /* Fetch step 1 values */
1064 crypt_scheme = packet_get_string(NULL);
1065 salt = packet_get_string(NULL);
1066 pctx->server_id = packet_get_string(&pctx->server_id_len);
1067 packet_get_bignum2(pctx->g_x3);
1068 packet_get_bignum2(pctx->g_x4);
1069 x3_proof = packet_get_string(&x3_proof_len);
1070 x4_proof = packet_get_string(&x4_proof_len);
1071 packet_check_eom();
1072
1073 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
1074
1075 /* Obtain password and derive secret */
1076 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
1077 bzero(crypt_scheme, strlen(crypt_scheme));
1078 bzero(salt, strlen(salt));
1079 xfree(crypt_scheme);
1080 xfree(salt);
1081 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
1082
1083 /* Calculate step 2 values */
1084 jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
1085 pctx->g_x3, pctx->g_x4, pctx->x2,
1086 pctx->server_id, pctx->server_id_len,
1087 pctx->client_id, pctx->client_id_len,
1088 x3_proof, x3_proof_len,
1089 x4_proof, x4_proof_len,
1090 &pctx->a,
1091 &x2_s_proof, &x2_s_proof_len);
1092
1093 bzero(x3_proof, x3_proof_len);
1094 bzero(x4_proof, x4_proof_len);
1095 xfree(x3_proof);
1096 xfree(x4_proof);
1097
1098 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
1099
1100 /* Send values for step 2 */
1101 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
1102 packet_put_bignum2(pctx->a);
1103 packet_put_string(x2_s_proof, x2_s_proof_len);
1104 packet_send();
1105
1106 bzero(x2_s_proof, x2_s_proof_len);
1107 xfree(x2_s_proof);
1108
1109 /* Expect step 2 packet from peer */
1110 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1111 input_userauth_jpake_server_step2);
1112}
1113
1114/* ARGSUSED */
1115void
1116input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1117{
1118 Authctxt *authctxt = ctxt;
1119 struct jpake_ctx *pctx = authctxt->methoddata;
1120 u_char *x4_s_proof;
1121 u_int x4_s_proof_len;
1122
1123 /* Disable this message */
1124 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1125
1126 if ((pctx->b = BN_new()) == NULL)
1127 fatal("%s: BN_new", __func__);
1128
1129 /* Fetch step 2 values */
1130 packet_get_bignum2(pctx->b);
1131 x4_s_proof = packet_get_string(&x4_s_proof_len);
1132 packet_check_eom();
1133
1134 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1135
1136 /* Derive shared key and calculate confirmation hash */
1137 jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1138 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1139 pctx->client_id, pctx->client_id_len,
1140 pctx->server_id, pctx->server_id_len,
1141 session_id2, session_id2_len,
1142 x4_s_proof, x4_s_proof_len,
1143 &pctx->k,
1144 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1145
1146 bzero(x4_s_proof, x4_s_proof_len);
1147 xfree(x4_s_proof);
1148
1149 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1150
1151 /* Send key confirmation proof */
1152 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1153 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1154 packet_send();
1155
1156 /* Expect confirmation from peer */
1157 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1158 input_userauth_jpake_server_confirm);
1159}
1160
1161/* ARGSUSED */
1162void
1163input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1164{
1165 Authctxt *authctxt = ctxt;
1166 struct jpake_ctx *pctx = authctxt->methoddata;
1167
1168 /* Disable this message */
1169 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1170
1171 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1172 packet_check_eom();
1173
1174 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1175
1176 /* Verify expected confirmation hash */
1177 if (jpake_check_confirm(pctx->k,
1178 pctx->server_id, pctx->server_id_len,
1179 session_id2, session_id2_len,
1180 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1181 debug("%s: %s success", __func__, authctxt->method->name);
1182 else {
1183 debug("%s: confirmation mismatch", __func__);
1184 /* XXX stash this so if auth succeeds then we can warn/kill */
1185 }
1186
1187 userauth_jpake_cleanup(authctxt);
1188}
1189#endif /* JPAKE */
1190
0fff78ff 1191static int
1192identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1193 u_char *data, u_int datalen)
3c0ef626 1194{
0fff78ff 1195 Key *prv;
1196 int ret;
700318f3 1197
0fff78ff 1198 /* the agent supports this key */
1199 if (id->ac)
1200 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1201 data, datalen));
1202 /*
1203 * we have already loaded the private key or
1204 * the private key is stored in external hardware
1205 */
1206 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1207 return (key_sign(id->key, sigp, lenp, data, datalen));
1208 /* load the private key from the file */
1209 if ((prv = load_identity_file(id->filename)) == NULL)
1210 return (-1);
1211 ret = key_sign(prv, sigp, lenp, data, datalen);
1212 key_free(prv);
1213 return (ret);
3c0ef626 1214}
1215
1216static int
0fff78ff 1217sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
3c0ef626 1218{
1219 Buffer b;
1220 u_char *blob, *signature;
e9a17296 1221 u_int bloblen, slen;
0fff78ff 1222 u_int skip = 0;
3c0ef626 1223 int ret = -1;
1224 int have_sig = 1;
1225
1226 debug3("sign_and_send_pubkey");
1227
0fff78ff 1228 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
3c0ef626 1229 /* we cannot handle this key */
1230 debug3("sign_and_send_pubkey: cannot handle key");
1231 return 0;
1232 }
1233 /* data to be signed */
1234 buffer_init(&b);
1235 if (datafellows & SSH_OLD_SESSIONID) {
1236 buffer_append(&b, session_id2, session_id2_len);
1237 skip = session_id2_len;
1238 } else {
1239 buffer_put_string(&b, session_id2, session_id2_len);
1240 skip = buffer_len(&b);
1241 }
1242 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1243 buffer_put_cstring(&b, authctxt->server_user);
1244 buffer_put_cstring(&b,
1245 datafellows & SSH_BUG_PKSERVICE ?
1246 "ssh-userauth" :
1247 authctxt->service);
1248 if (datafellows & SSH_BUG_PKAUTH) {
1249 buffer_put_char(&b, have_sig);
1250 } else {
1251 buffer_put_cstring(&b, authctxt->method->name);
1252 buffer_put_char(&b, have_sig);
0fff78ff 1253 buffer_put_cstring(&b, key_ssh_name(id->key));
3c0ef626 1254 }
1255 buffer_put_string(&b, blob, bloblen);
1256
1257 /* generate signature */
0fff78ff 1258 ret = identity_sign(id, &signature, &slen,
3c0ef626 1259 buffer_ptr(&b), buffer_len(&b));
1260 if (ret == -1) {
1261 xfree(blob);
1262 buffer_free(&b);
1263 return 0;
1264 }
1265#ifdef DEBUG_PK
1266 buffer_dump(&b);
1267#endif
1268 if (datafellows & SSH_BUG_PKSERVICE) {
1269 buffer_clear(&b);
1270 buffer_append(&b, session_id2, session_id2_len);
1271 skip = session_id2_len;
1272 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1273 buffer_put_cstring(&b, authctxt->server_user);
1274 buffer_put_cstring(&b, authctxt->service);
1275 buffer_put_cstring(&b, authctxt->method->name);
1276 buffer_put_char(&b, have_sig);
1277 if (!(datafellows & SSH_BUG_PKAUTH))
0fff78ff 1278 buffer_put_cstring(&b, key_ssh_name(id->key));
3c0ef626 1279 buffer_put_string(&b, blob, bloblen);
1280 }
1281 xfree(blob);
1282
1283 /* append signature */
1284 buffer_put_string(&b, signature, slen);
1285 xfree(signature);
1286
1287 /* skip session id and packet type */
1288 if (buffer_len(&b) < skip + 1)
1289 fatal("userauth_pubkey: internal error");
1290 buffer_consume(&b, skip + 1);
1291
1292 /* put remaining data from buffer into packet */
1293 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1294 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1295 buffer_free(&b);
1296 packet_send();
1297
1298 return 1;
1299}
1300
1301static int
0fff78ff 1302send_pubkey_test(Authctxt *authctxt, Identity *id)
3c0ef626 1303{
1304 u_char *blob;
e9a17296 1305 u_int bloblen, have_sig = 0;
3c0ef626 1306
1307 debug3("send_pubkey_test");
1308
0fff78ff 1309 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
3c0ef626 1310 /* we cannot handle this key */
1311 debug3("send_pubkey_test: cannot handle key");
1312 return 0;
1313 }
1314 /* register callback for USERAUTH_PK_OK message */
3c0ef626 1315 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1316
1317 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1318 packet_put_cstring(authctxt->server_user);
1319 packet_put_cstring(authctxt->service);
1320 packet_put_cstring(authctxt->method->name);
1321 packet_put_char(have_sig);
1322 if (!(datafellows & SSH_BUG_PKAUTH))
0fff78ff 1323 packet_put_cstring(key_ssh_name(id->key));
3c0ef626 1324 packet_put_string(blob, bloblen);
1325 xfree(blob);
1326 packet_send();
1327 return 1;
1328}
1329
1330static Key *
1331load_identity_file(char *filename)
1332{
1333 Key *private;
1334 char prompt[300], *passphrase;
9108f8d9 1335 int perm_ok, quit, i;
3c0ef626 1336 struct stat st;
1337
1338 if (stat(filename, &st) < 0) {
1339 debug3("no such identity: %s", filename);
1340 return NULL;
1341 }
9108f8d9 1342 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1343 if (!perm_ok)
1344 return NULL;
3c0ef626 1345 if (private == NULL) {
1346 if (options.batch_mode)
1347 return NULL;
1348 snprintf(prompt, sizeof prompt,
e9a17296 1349 "Enter passphrase for key '%.100s': ", filename);
3c0ef626 1350 for (i = 0; i < options.number_of_password_prompts; i++) {
1351 passphrase = read_passphrase(prompt, 0);
1352 if (strcmp(passphrase, "") != 0) {
9108f8d9 1353 private = key_load_private_type(KEY_UNSPEC,
1354 filename, passphrase, NULL, NULL);
3c0ef626 1355 quit = 0;
1356 } else {
1357 debug2("no passphrase given, try next key");
1358 quit = 1;
1359 }
1360 memset(passphrase, 0, strlen(passphrase));
1361 xfree(passphrase);
1362 if (private != NULL || quit)
1363 break;
1364 debug2("bad passphrase given, try again...");
1365 }
1366 }
1367 return private;
1368}
1369
0fff78ff 1370/*
1371 * try keys in the following order:
1372 * 1. agent keys that are found in the config file
1373 * 2. other agent keys
1374 * 3. keys that are only listed in the config file
1375 */
1376static void
1377pubkey_prepare(Authctxt *authctxt)
3c0ef626 1378{
0fff78ff 1379 Identity *id;
1380 Idlist agent, files, *preferred;
1381 Key *key;
1382 AuthenticationConnection *ac;
1383 char *comment;
1384 int i, found;
1385
1386 TAILQ_INIT(&agent); /* keys from the agent */
1387 TAILQ_INIT(&files); /* keys from the config file */
1388 preferred = &authctxt->keys;
1389 TAILQ_INIT(preferred); /* preferred order of keys */
1390
1391 /* list of keys stored in the filesystem */
1392 for (i = 0; i < options.num_identity_files; i++) {
1393 key = options.identity_keys[i];
1394 if (key && key->type == KEY_RSA1)
1395 continue;
1396 options.identity_keys[i] = NULL;
9108f8d9 1397 id = xcalloc(1, sizeof(*id));
0fff78ff 1398 id->key = key;
1399 id->filename = xstrdup(options.identity_files[i]);
1400 TAILQ_INSERT_TAIL(&files, id, next);
1401 }
1402 /* list of keys supported by the agent */
1403 if ((ac = ssh_get_authentication_connection())) {
1404 for (key = ssh_get_first_identity(ac, &comment, 2);
1405 key != NULL;
1406 key = ssh_get_next_identity(ac, &comment, 2)) {
1407 found = 0;
1408 TAILQ_FOREACH(id, &files, next) {
cdd66111 1409 /* agent keys from the config file are preferred */
0fff78ff 1410 if (key_equal(key, id->key)) {
1411 key_free(key);
1412 xfree(comment);
1413 TAILQ_REMOVE(&files, id, next);
1414 TAILQ_INSERT_TAIL(preferred, id, next);
1415 id->ac = ac;
1416 found = 1;
1417 break;
1418 }
1419 }
99be0775 1420 if (!found && !options.identities_only) {
9108f8d9 1421 id = xcalloc(1, sizeof(*id));
0fff78ff 1422 id->key = key;
1423 id->filename = comment;
1424 id->ac = ac;
1425 TAILQ_INSERT_TAIL(&agent, id, next);
1426 }
1427 }
1428 /* append remaining agent keys */
1429 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1430 TAILQ_REMOVE(&agent, id, next);
1431 TAILQ_INSERT_TAIL(preferred, id, next);
1432 }
1433 authctxt->agent = ac;
1434 }
1435 /* append remaining keys from the config file */
1436 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1437 TAILQ_REMOVE(&files, id, next);
1438 TAILQ_INSERT_TAIL(preferred, id, next);
1439 }
1440 TAILQ_FOREACH(id, preferred, next) {
1441 debug2("key: %s (%p)", id->filename, id->key);
1442 }
3c0ef626 1443}
1444
0fff78ff 1445static void
1446pubkey_cleanup(Authctxt *authctxt)
3c0ef626 1447{
0fff78ff 1448 Identity *id;
1449
1450 if (authctxt->agent != NULL)
1451 ssh_close_authentication_connection(authctxt->agent);
1452 for (id = TAILQ_FIRST(&authctxt->keys); id;
1453 id = TAILQ_FIRST(&authctxt->keys)) {
1454 TAILQ_REMOVE(&authctxt->keys, id, next);
1455 if (id->key)
1456 key_free(id->key);
1457 if (id->filename)
1458 xfree(id->filename);
1459 xfree(id);
3c0ef626 1460 }
3c0ef626 1461}
1462
1463int
1464userauth_pubkey(Authctxt *authctxt)
1465{
0fff78ff 1466 Identity *id;
3c0ef626 1467 int sent = 0;
0fff78ff 1468
1469 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1470 if (id->tried++)
1471 return (0);
cdd66111 1472 /* move key to the end of the queue */
0fff78ff 1473 TAILQ_REMOVE(&authctxt->keys, id, next);
1474 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1475 /*
1476 * send a test message if we have the public key. for
1477 * encrypted keys we cannot do this and have to load the
1478 * private key instead
1479 */
1480 if (id->key && id->key->type != KEY_RSA1) {
1481 debug("Offering public key: %s", id->filename);
1482 sent = send_pubkey_test(authctxt, id);
1483 } else if (id->key == NULL) {
1484 debug("Trying private key: %s", id->filename);
1485 id->key = load_identity_file(id->filename);
1486 if (id->key != NULL) {
1487 id->isprivate = 1;
1488 sent = sign_and_send_pubkey(authctxt, id);
1489 key_free(id->key);
1490 id->key = NULL;
3c0ef626 1491 }
3c0ef626 1492 }
0fff78ff 1493 if (sent)
1494 return (sent);
3c0ef626 1495 }
0fff78ff 1496 return (0);
3c0ef626 1497}
1498
1499/*
1500 * Send userauth request message specifying keyboard-interactive method.
1501 */
1502int
1503userauth_kbdint(Authctxt *authctxt)
1504{
1505 static int attempt = 0;
1506
1507 if (attempt++ >= options.number_of_password_prompts)
1508 return 0;
1509 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1510 if (attempt > 1 && !authctxt->info_req_seen) {
1511 debug3("userauth_kbdint: disable: no info_req_seen");
1512 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1513 return 0;
1514 }
1515
1516 debug2("userauth_kbdint");
1517 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1518 packet_put_cstring(authctxt->server_user);
1519 packet_put_cstring(authctxt->service);
1520 packet_put_cstring(authctxt->method->name);
1521 packet_put_cstring(""); /* lang */
1522 packet_put_cstring(options.kbd_interactive_devices ?
1523 options.kbd_interactive_devices : "");
1524 packet_send();
1525
1526 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1527 return 1;
1528}
1529
1530/*
1531 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1532 */
1533void
e9a17296 1534input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
3c0ef626 1535{
1536 Authctxt *authctxt = ctxt;
1537 char *name, *inst, *lang, *prompt, *response;
1538 u_int num_prompts, i;
1539 int echo = 0;
1540
1541 debug2("input_userauth_info_req");
1542
1543 if (authctxt == NULL)
1544 fatal("input_userauth_info_req: no authentication context");
1545
1546 authctxt->info_req_seen = 1;
1547
1548 name = packet_get_string(NULL);
1549 inst = packet_get_string(NULL);
1550 lang = packet_get_string(NULL);
1551 if (strlen(name) > 0)
0fff78ff 1552 logit("%s", name);
3c0ef626 1553 if (strlen(inst) > 0)
0fff78ff 1554 logit("%s", inst);
3c0ef626 1555 xfree(name);
1556 xfree(inst);
1557 xfree(lang);
1558
1559 num_prompts = packet_get_int();
1560 /*
1561 * Begin to build info response packet based on prompts requested.
1562 * We commit to providing the correct number of responses, so if
1563 * further on we run into a problem that prevents this, we have to
1564 * be sure and clean this up and send a correct error response.
1565 */
1566 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1567 packet_put_int(num_prompts);
1568
1569 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1570 for (i = 0; i < num_prompts; i++) {
1571 prompt = packet_get_string(NULL);
1572 echo = packet_get_char();
1573
1574 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1575
1576 packet_put_cstring(response);
1577 memset(response, 0, strlen(response));
1578 xfree(response);
1579 xfree(prompt);
1580 }
e9a17296 1581 packet_check_eom(); /* done with parsing incoming message. */
3c0ef626 1582
1583 packet_add_padding(64);
1584 packet_send();
1585}
1586
f5799ae1 1587static int
680cee3b 1588ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
f5799ae1 1589 u_char *data, u_int datalen)
1590{
1591 Buffer b;
1592 struct stat st;
1593 pid_t pid;
1594 int to[2], from[2], status, version = 2;
1595
6a9b3198 1596 debug2("ssh_keysign called");
f5799ae1 1597
1598 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1599 error("ssh_keysign: no installed: %s", strerror(errno));
1600 return -1;
1601 }
1602 if (fflush(stdout) != 0)
1603 error("ssh_keysign: fflush: %s", strerror(errno));
1604 if (pipe(to) < 0) {
1605 error("ssh_keysign: pipe: %s", strerror(errno));
1606 return -1;
1607 }
1608 if (pipe(from) < 0) {
1609 error("ssh_keysign: pipe: %s", strerror(errno));
1610 return -1;
1611 }
1612 if ((pid = fork()) < 0) {
1613 error("ssh_keysign: fork: %s", strerror(errno));
1614 return -1;
1615 }
1616 if (pid == 0) {
9108f8d9 1617 permanently_drop_suid(getuid());
f5799ae1 1618 close(from[0]);
1619 if (dup2(from[1], STDOUT_FILENO) < 0)
1620 fatal("ssh_keysign: dup2: %s", strerror(errno));
1621 close(to[1]);
1622 if (dup2(to[0], STDIN_FILENO) < 0)
1623 fatal("ssh_keysign: dup2: %s", strerror(errno));
1624 close(from[1]);
1625 close(to[0]);
1626 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1627 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1628 strerror(errno));
1629 }
1630 close(from[1]);
1631 close(to[0]);
1632
1633 buffer_init(&b);
1634 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1635 buffer_put_string(&b, data, datalen);
cdd66111 1636 if (ssh_msg_send(to[1], version, &b) == -1)
1637 fatal("ssh_keysign: couldn't send request");
f5799ae1 1638
41b2f314 1639 if (ssh_msg_recv(from[0], &b) < 0) {
f5799ae1 1640 error("ssh_keysign: no reply");
cdd66111 1641 buffer_free(&b);
f5799ae1 1642 return -1;
1643 }
1644 close(from[0]);
1645 close(to[1]);
1646
1647 while (waitpid(pid, &status, 0) < 0)
1648 if (errno != EINTR)
1649 break;
1650
1651 if (buffer_get_char(&b) != version) {
1652 error("ssh_keysign: bad version");
cdd66111 1653 buffer_free(&b);
f5799ae1 1654 return -1;
1655 }
1656 *sigp = buffer_get_string(&b, lenp);
cdd66111 1657 buffer_free(&b);
f5799ae1 1658
1659 return 0;
1660}
1661
3c0ef626 1662int
1663userauth_hostbased(Authctxt *authctxt)
1664{
1665 Key *private = NULL;
f5799ae1 1666 Sensitive *sensitive = authctxt->sensitive;
3c0ef626 1667 Buffer b;
1668 u_char *signature, *blob;
d4487008 1669 char *chost, *pkalg, *p, myname[NI_MAXHOST];
3c0ef626 1670 const char *service;
1671 u_int blen, slen;
1672 int ok, i, len, found = 0;
1673
1674 /* check for a useful key */
f5799ae1 1675 for (i = 0; i < sensitive->nkeys; i++) {
1676 private = sensitive->keys[i];
3c0ef626 1677 if (private && private->type != KEY_RSA1) {
1678 found = 1;
1679 /* we take and free the key */
f5799ae1 1680 sensitive->keys[i] = NULL;
3c0ef626 1681 break;
1682 }
1683 }
1684 if (!found) {
6a9b3198 1685 debug("No more client hostkeys for hostbased authentication.");
3c0ef626 1686 return 0;
1687 }
1688 if (key_to_blob(private, &blob, &blen) == 0) {
1689 key_free(private);
1690 return 0;
1691 }
1692 /* figure out a name for the client host */
d4487008 1693 p = NULL;
1694 if (packet_connection_is_on_socket())
1695 p = get_local_name(packet_get_connection_in());
1696 if (p == NULL) {
1697 if (gethostname(myname, sizeof(myname)) == -1) {
1698 verbose("userauth_hostbased: gethostname: %s",
1699 strerror(errno));
1700 } else
1701 p = xstrdup(myname);
1702 }
3c0ef626 1703 if (p == NULL) {
1704 error("userauth_hostbased: cannot get local ipaddr/name");
1705 key_free(private);
9108f8d9 1706 xfree(blob);
3c0ef626 1707 return 0;
1708 }
1709 len = strlen(p) + 2;
9108f8d9 1710 xasprintf(&chost, "%s.", p);
3c0ef626 1711 debug2("userauth_hostbased: chost %s", chost);
6a9b3198 1712 xfree(p);
3c0ef626 1713
1714 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1715 authctxt->service;
1716 pkalg = xstrdup(key_ssh_name(private));
1717 buffer_init(&b);
1718 /* construct data */
1719 buffer_put_string(&b, session_id2, session_id2_len);
1720 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1721 buffer_put_cstring(&b, authctxt->server_user);
1722 buffer_put_cstring(&b, service);
1723 buffer_put_cstring(&b, authctxt->method->name);
1724 buffer_put_cstring(&b, pkalg);
1725 buffer_put_string(&b, blob, blen);
1726 buffer_put_cstring(&b, chost);
1727 buffer_put_cstring(&b, authctxt->local_user);
1728#ifdef DEBUG_PK
1729 buffer_dump(&b);
1730#endif
f5799ae1 1731 if (sensitive->external_keysign)
1732 ok = ssh_keysign(private, &signature, &slen,
1733 buffer_ptr(&b), buffer_len(&b));
1734 else
1735 ok = key_sign(private, &signature, &slen,
1736 buffer_ptr(&b), buffer_len(&b));
3c0ef626 1737 key_free(private);
1738 buffer_free(&b);
1739 if (ok != 0) {
1740 error("key_sign failed");
1741 xfree(chost);
1742 xfree(pkalg);
9108f8d9 1743 xfree(blob);
3c0ef626 1744 return 0;
1745 }
1746 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1747 packet_put_cstring(authctxt->server_user);
1748 packet_put_cstring(authctxt->service);
1749 packet_put_cstring(authctxt->method->name);
1750 packet_put_cstring(pkalg);
1751 packet_put_string(blob, blen);
1752 packet_put_cstring(chost);
1753 packet_put_cstring(authctxt->local_user);
1754 packet_put_string(signature, slen);
1755 memset(signature, 's', slen);
1756 xfree(signature);
1757 xfree(chost);
1758 xfree(pkalg);
9108f8d9 1759 xfree(blob);
3c0ef626 1760
1761 packet_send();
1762 return 1;
1763}
1764
91d9cdd3 1765#ifdef JPAKE
1766int
1767userauth_jpake(Authctxt *authctxt)
1768{
1769 struct jpake_ctx *pctx;
1770 u_char *x1_proof, *x2_proof;
1771 u_int x1_proof_len, x2_proof_len;
1772 static int attempt = 0; /* XXX share with userauth_password's? */
1773
1774 if (attempt++ >= options.number_of_password_prompts)
1775 return 0;
1776 if (attempt != 1)
1777 error("Permission denied, please try again.");
1778
1779 if (authctxt->methoddata != NULL)
1780 fatal("%s: authctxt->methoddata already set (%p)",
1781 __func__, authctxt->methoddata);
1782
1783 authctxt->methoddata = pctx = jpake_new();
1784
1785 /*
1786 * Send request immediately, to get the protocol going while
1787 * we do the initial computations.
1788 */
1789 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1790 packet_put_cstring(authctxt->server_user);
1791 packet_put_cstring(authctxt->service);
1792 packet_put_cstring(authctxt->method->name);
1793 packet_send();
1794 packet_write_wait();
1795
1796 jpake_step1(pctx->grp,
1797 &pctx->client_id, &pctx->client_id_len,
1798 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1799 &x1_proof, &x1_proof_len,
1800 &x2_proof, &x2_proof_len);
1801
1802 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1803
1804 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1805 packet_put_string(pctx->client_id, pctx->client_id_len);
1806 packet_put_bignum2(pctx->g_x1);
1807 packet_put_bignum2(pctx->g_x2);
1808 packet_put_string(x1_proof, x1_proof_len);
1809 packet_put_string(x2_proof, x2_proof_len);
1810 packet_send();
1811
1812 bzero(x1_proof, x1_proof_len);
1813 bzero(x2_proof, x2_proof_len);
1814 xfree(x1_proof);
1815 xfree(x2_proof);
1816
1817 /* Expect step 1 packet from peer */
1818 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1819 input_userauth_jpake_server_step1);
1820
1821 return 1;
1822}
1823
1824void
1825userauth_jpake_cleanup(Authctxt *authctxt)
1826{
1827 debug3("%s: clean up", __func__);
1828 if (authctxt->methoddata != NULL) {
1829 jpake_free(authctxt->methoddata);
1830 authctxt->methoddata = NULL;
1831 }
1832}
1833#endif /* JPAKE */
1834
3c0ef626 1835/* find auth method */
1836
1837/*
1838 * given auth method name, if configurable options permit this method fill
1839 * in auth_ident field and return true, otherwise return false.
1840 */
1841static int
1842authmethod_is_enabled(Authmethod *method)
1843{
1844 if (method == NULL)
1845 return 0;
1846 /* return false if options indicate this method is disabled */
1847 if (method->enabled == NULL || *method->enabled == 0)
1848 return 0;
1849 /* return false if batch mode is enabled but method needs interactive mode */
1850 if (method->batch_flag != NULL && *method->batch_flag != 0)
1851 return 0;
1852 return 1;
1853}
1854
1855static Authmethod *
1856authmethod_lookup(const char *name)
1857{
1858 Authmethod *method = NULL;
1859 if (name != NULL)
1860 for (method = authmethods; method->name != NULL; method++)
1861 if (strcmp(name, method->name) == 0)
1862 return method;
1863 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1864 return NULL;
1865}
1866
1867/* XXX internal state */
1868static Authmethod *current = NULL;
1869static char *supported = NULL;
1870static char *preferred = NULL;
680cee3b 1871
3c0ef626 1872/*
1873 * Given the authentication method list sent by the server, return the
1874 * next method we should try. If the server initially sends a nil list,
1875 * use a built-in default list.
1876 */
1877static Authmethod *
1878authmethod_get(char *authlist)
1879{
3c0ef626 1880 char *name = NULL;
e9a17296 1881 u_int next;
3c0ef626 1882
1883 /* Use a suitable default if we're passed a nil list. */
1884 if (authlist == NULL || strlen(authlist) == 0)
1885 authlist = options.preferred_authentications;
1886
1887 if (supported == NULL || strcmp(authlist, supported) != 0) {
1888 debug3("start over, passed a different list %s", authlist);
1889 if (supported != NULL)
1890 xfree(supported);
1891 supported = xstrdup(authlist);
1892 preferred = options.preferred_authentications;
1893 debug3("preferred %s", preferred);
1894 current = NULL;
1895 } else if (current != NULL && authmethod_is_enabled(current))
1896 return current;
1897
1898 for (;;) {
1899 if ((name = match_list(preferred, supported, &next)) == NULL) {
6a9b3198 1900 debug("No more authentication methods to try.");
3c0ef626 1901 current = NULL;
1902 return NULL;
1903 }
1904 preferred += next;
1905 debug3("authmethod_lookup %s", name);
1906 debug3("remaining preferred: %s", preferred);
1907 if ((current = authmethod_lookup(name)) != NULL &&
1908 authmethod_is_enabled(current)) {
1909 debug3("authmethod_is_enabled %s", name);
6a9b3198 1910 debug("Next authentication method: %s", name);
3c0ef626 1911 return current;
1912 }
1913 }
1914}
1915
3c0ef626 1916static char *
1917authmethods_get(void)
1918{
1919 Authmethod *method = NULL;
e9a17296 1920 Buffer b;
1921 char *list;
3c0ef626 1922
e9a17296 1923 buffer_init(&b);
3c0ef626 1924 for (method = authmethods; method->name != NULL; method++) {
1925 if (authmethod_is_enabled(method)) {
e9a17296 1926 if (buffer_len(&b) > 0)
1927 buffer_append(&b, ",", 1);
1928 buffer_append(&b, method->name, strlen(method->name));
3c0ef626 1929 }
1930 }
e9a17296 1931 buffer_append(&b, "\0", 1);
1932 list = xstrdup(buffer_ptr(&b));
1933 buffer_free(&b);
1934 return list;
3c0ef626 1935}
91d9cdd3 1936
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