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merged OpenSSH 3.4p1 to trunk
[gssapi-openssh.git] / openssh / sshconnect2.c
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3c0ef626 1/*
2 * Copyright (c) 2000 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
276b07a3 26RCSID("$OpenBSD: sshconnect2.c,v 1.105 2002/06/23 03:30:17 deraadt Exp $");
3c0ef626 27
28#include "ssh.h"
29#include "ssh2.h"
30#include "xmalloc.h"
3c0ef626 31#include "buffer.h"
32#include "packet.h"
3c0ef626 33#include "compat.h"
34#include "bufaux.h"
35#include "cipher.h"
36#include "kex.h"
37#include "myproposal.h"
3c0ef626 38#include "sshconnect.h"
39#include "authfile.h"
40#include "dh.h"
41#include "authfd.h"
42#include "log.h"
43#include "readconf.h"
44#include "readpass.h"
45#include "match.h"
46#include "dispatch.h"
47#include "canohost.h"
44a053a3 48#include "msg.h"
49#include "pathnames.h"
3c0ef626 50
5598e598 51#ifdef GSSAPI
52#include "ssh-gss.h"
53#endif
54
3c0ef626 55/* import */
56extern char *client_version_string;
57extern char *server_version_string;
58extern Options options;
59
60/*
61 * SSH2 key exchange
62 */
63
64u_char *session_id2 = NULL;
65int session_id2_len = 0;
66
67char *xxx_host;
68struct sockaddr *xxx_hostaddr;
69
70Kex *xxx_kex = NULL;
71
72static int
73verify_host_key_callback(Key *hostkey)
74{
75 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
76 fatal("Host key verification failed.");
77 return 0;
78}
79
80void
81ssh_kex2(char *host, struct sockaddr *hostaddr)
82{
83 Kex *kex;
1e608e42 84#ifdef GSSAPI
85 char *orig, *gss;
86 int len;
87#endif
3c0ef626 88
89 xxx_host = host;
90 xxx_hostaddr = hostaddr;
91
5598e598 92#ifdef GSSAPI
1e608e42 93 /* Add the GSSAPI mechanisms currently supported on this client to
94 * the key exchange algorithm proposal */
95 orig = myproposal[PROPOSAL_KEX_ALGS];
96 gss = ssh_gssapi_mechanisms(0,host);
97 if (gss) {
98 len = strlen(orig)+strlen(gss)+2;
99 myproposal[PROPOSAL_KEX_ALGS]=xmalloc(len);
100 snprintf(myproposal[PROPOSAL_KEX_ALGS],len,"%s,%s",gss,orig);
5598e598 101 }
102#endif
103
3c0ef626 104 if (options.ciphers == (char *)-1) {
105 log("No valid ciphers for protocol version 2 given, using defaults.");
106 options.ciphers = NULL;
107 }
108 if (options.ciphers != NULL) {
109 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
110 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
111 }
112 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
113 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
114 myproposal[PROPOSAL_ENC_ALGS_STOC] =
115 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
116 if (options.compression) {
117 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
118 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
119 } else {
120 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
121 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
122 }
123 if (options.macs != NULL) {
124 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
125 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
126 }
127 if (options.hostkeyalgorithms != NULL)
1e608e42 128 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
3c0ef626 129 options.hostkeyalgorithms;
130
1e608e42 131#ifdef GSSAPI
132 /* If we've got GSSAPI algorithms, then we also support the
133 * 'null' hostkey, as a last resort */
134 if (gss) {
135 orig=myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS];
136 len = strlen(orig)+sizeof(",null");
137 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]=xmalloc(len);
138 snprintf(myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS],len,"%s,null",orig);
139 }
140#endif
141
3c0ef626 142 /* start key exchange */
143 kex = kex_setup(myproposal);
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;
5598e598 147 kex->host=host;
148
149#ifdef GSSAPI
150 kex->options.gss_deleg_creds=options.gss_deleg_creds;
151#endif
3c0ef626 152
153 xxx_kex = kex;
154
155 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
156
157 session_id2 = kex->session_id;
158 session_id2_len = kex->session_id_len;
159
160#ifdef DEBUG_KEXDH
161 /* send 1st encrypted/maced/compressed message */
162 packet_start(SSH2_MSG_IGNORE);
163 packet_put_cstring("markus");
164 packet_send();
165 packet_write_wait();
166#endif
167 debug("done: ssh_kex2.");
168}
169
170/*
171 * Authenticate user
172 */
173
174typedef struct Authctxt Authctxt;
175typedef struct Authmethod Authmethod;
176
177typedef int sign_cb_fn(
178 Authctxt *authctxt, Key *key,
1e608e42 179 u_char **sigp, u_int *lenp, u_char *data, u_int datalen);
3c0ef626 180
181struct Authctxt {
182 const char *server_user;
183 const char *local_user;
184 const char *host;
185 const char *service;
186 Authmethod *method;
187 int success;
188 char *authlist;
189 /* pubkey */
190 Key *last_key;
191 sign_cb_fn *last_key_sign;
192 int last_key_hint;
193 AuthenticationConnection *agent;
194 /* hostbased */
44a053a3 195 Sensitive *sensitive;
3c0ef626 196 /* kbd-interactive */
197 int info_req_seen;
5598e598 198 /* generic */
199 void *methoddata;
3c0ef626 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
1e608e42 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 *);
510132b6 214void input_userauth_passwd_changereq(int, u_int32_t, void *);
3c0ef626 215
1e608e42 216int userauth_none(Authctxt *);
217int userauth_pubkey(Authctxt *);
218int userauth_passwd(Authctxt *);
219int userauth_kbdint(Authctxt *);
220int userauth_hostbased(Authctxt *);
3c0ef626 221
5598e598 222#ifdef GSSAPI
1e608e42 223int userauth_external(Authctxt *authctxt);
224int userauth_gssapi(Authctxt *authctxt);
225void input_gssapi_response(int type, u_int32_t plen, void *ctxt);
226void input_gssapi_token(int type, u_int32_t plen, void *ctxt);
227void input_gssapi_hash(int type, u_int32_t plen, void *ctxt);
5598e598 228#endif
229
1e608e42 230void userauth(Authctxt *, char *);
3c0ef626 231
232static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
233static void clear_auth_state(Authctxt *);
234
235static Authmethod *authmethod_get(char *authlist);
236static Authmethod *authmethod_lookup(const char *name);
237static char *authmethods_get(void);
238
239Authmethod authmethods[] = {
5598e598 240#ifdef GSSAPI
241 {"external-keyx",
242 userauth_external,
243 &options.gss_authentication,
244 NULL},
245 {"gssapi",
246 userauth_gssapi,
247 &options.gss_authentication,
248 NULL},
249#endif
3c0ef626 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,
44a053a3 275 Sensitive *sensitive)
3c0ef626 276{
277 Authctxt authctxt;
278 int type;
3c0ef626 279
280 if (options.challenge_response_authentication)
281 options.kbd_interactive_authentication = 1;
282
283 debug("send SSH2_MSG_SERVICE_REQUEST");
284 packet_start(SSH2_MSG_SERVICE_REQUEST);
285 packet_put_cstring("ssh-userauth");
286 packet_send();
287 packet_write_wait();
1e608e42 288 type = packet_read();
3c0ef626 289 if (type != SSH2_MSG_SERVICE_ACCEPT) {
290 fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
291 }
292 if (packet_remaining() > 0) {
1e608e42 293 char *reply = packet_get_string(NULL);
3c0ef626 294 debug("service_accept: %s", reply);
295 xfree(reply);
296 } else {
297 debug("buggy server: service_accept w/o service");
298 }
1e608e42 299 packet_check_eom();
3c0ef626 300 debug("got SSH2_MSG_SERVICE_ACCEPT");
301
302 if (options.preferred_authentications == NULL)
303 options.preferred_authentications = authmethods_get();
304
305 /* setup authentication context */
306 memset(&authctxt, 0, sizeof(authctxt));
307 authctxt.agent = ssh_get_authentication_connection();
308 authctxt.server_user = server_user;
309 authctxt.local_user = local_user;
310 authctxt.host = host;
311 authctxt.service = "ssh-connection"; /* service name */
312 authctxt.success = 0;
313 authctxt.method = authmethod_lookup("none");
314 authctxt.authlist = NULL;
5598e598 315 authctxt.methoddata = NULL;
44a053a3 316 authctxt.sensitive = sensitive;
3c0ef626 317 authctxt.info_req_seen = 0;
318 if (authctxt.method == NULL)
319 fatal("ssh_userauth2: internal error: cannot send userauth none request");
320
321 /* initial userauth request */
322 userauth_none(&authctxt);
323
324 dispatch_init(&input_userauth_error);
325 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
326 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
327 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
328 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
329
330 if (authctxt.agent != NULL)
331 ssh_close_authentication_connection(authctxt.agent);
332
333 debug("ssh-userauth2 successful: method %s", authctxt.method->name);
334}
335void
336userauth(Authctxt *authctxt, char *authlist)
337{
5598e598 338 if (authctxt->methoddata!=NULL) {
339 xfree(authctxt->methoddata);
340 authctxt->methoddata=NULL;
341 }
342
3c0ef626 343 if (authlist == NULL) {
344 authlist = authctxt->authlist;
345 } else {
346 if (authctxt->authlist)
347 xfree(authctxt->authlist);
348 authctxt->authlist = authlist;
349 }
350 for (;;) {
351 Authmethod *method = authmethod_get(authlist);
352 if (method == NULL)
353 fatal("Permission denied (%s).", authlist);
354 authctxt->method = method;
355 if (method->userauth(authctxt) != 0) {
356 debug2("we sent a %s packet, wait for reply", method->name);
357 break;
358 } else {
359 debug2("we did not send a packet, disable method");
360 method->enabled = NULL;
361 }
362 }
363}
276b07a3 364
3c0ef626 365void
1e608e42 366input_userauth_error(int type, u_int32_t seq, void *ctxt)
3c0ef626 367{
368 fatal("input_userauth_error: bad message during authentication: "
369 "type %d", type);
370}
276b07a3 371
3c0ef626 372void
1e608e42 373input_userauth_banner(int type, u_int32_t seq, void *ctxt)
3c0ef626 374{
375 char *msg, *lang;
376 debug3("input_userauth_banner");
377 msg = packet_get_string(NULL);
378 lang = packet_get_string(NULL);
379 fprintf(stderr, "%s", msg);
380 xfree(msg);
381 xfree(lang);
382}
276b07a3 383
3c0ef626 384void
1e608e42 385input_userauth_success(int type, u_int32_t seq, void *ctxt)
3c0ef626 386{
387 Authctxt *authctxt = ctxt;
388 if (authctxt == NULL)
389 fatal("input_userauth_success: no authentication context");
390 if (authctxt->authlist)
391 xfree(authctxt->authlist);
5598e598 392 if (authctxt->methoddata)
393 xfree(authctxt->methoddata);
3c0ef626 394 clear_auth_state(authctxt);
395 authctxt->success = 1; /* break out */
396}
276b07a3 397
3c0ef626 398void
1e608e42 399input_userauth_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 400{
401 Authctxt *authctxt = ctxt;
402 char *authlist = NULL;
403 int partial;
404
405 if (authctxt == NULL)
406 fatal("input_userauth_failure: no authentication context");
407
408 authlist = packet_get_string(NULL);
409 partial = packet_get_char();
1e608e42 410 packet_check_eom();
3c0ef626 411
412 if (partial != 0)
413 log("Authenticated with partial success.");
414 debug("authentications that can continue: %s", authlist);
415
416 clear_auth_state(authctxt);
417 userauth(authctxt, authlist);
418}
419void
1e608e42 420input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
3c0ef626 421{
422 Authctxt *authctxt = ctxt;
423 Key *key = NULL;
424 Buffer b;
1e608e42 425 int pktype, sent = 0;
426 u_int alen, blen;
427 char *pkalg, *fp;
428 u_char *pkblob;
3c0ef626 429
430 if (authctxt == NULL)
431 fatal("input_userauth_pk_ok: no authentication context");
432 if (datafellows & SSH_BUG_PKOK) {
433 /* this is similar to SSH_BUG_PKAUTH */
434 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
435 pkblob = packet_get_string(&blen);
436 buffer_init(&b);
437 buffer_append(&b, pkblob, blen);
438 pkalg = buffer_get_string(&b, &alen);
439 buffer_free(&b);
440 } else {
441 pkalg = packet_get_string(&alen);
442 pkblob = packet_get_string(&blen);
443 }
1e608e42 444 packet_check_eom();
3c0ef626 445
276b07a3 446 debug("input_userauth_pk_ok: pkalg %s blen %u lastkey %p hint %d",
3c0ef626 447 pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
448
449 do {
450 if (authctxt->last_key == NULL ||
451 authctxt->last_key_sign == NULL) {
452 debug("no last key or no sign cb");
453 break;
454 }
1e608e42 455 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
3c0ef626 456 debug("unknown pkalg %s", pkalg);
457 break;
458 }
459 if ((key = key_from_blob(pkblob, blen)) == NULL) {
460 debug("no key from blob. pkalg %s", pkalg);
461 break;
462 }
510132b6 463 if (key->type != pktype) {
1e608e42 464 error("input_userauth_pk_ok: type mismatch "
465 "for decoded key (received %d, expected %d)",
44a053a3 466 key->type, pktype);
1e608e42 467 break;
468 }
3c0ef626 469 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
470 debug2("input_userauth_pk_ok: fp %s", fp);
471 xfree(fp);
472 if (!key_equal(key, authctxt->last_key)) {
473 debug("key != last_key");
474 break;
475 }
476 sent = sign_and_send_pubkey(authctxt, key,
477 authctxt->last_key_sign);
1e608e42 478 } while (0);
3c0ef626 479
480 if (key != NULL)
481 key_free(key);
482 xfree(pkalg);
483 xfree(pkblob);
484
485 /* unregister */
486 clear_auth_state(authctxt);
487 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
488
489 /* try another method if we did not send a packet*/
490 if (sent == 0)
491 userauth(authctxt, NULL);
492
493}
494
5598e598 495#ifdef GSSAPI
496int
497userauth_gssapi(Authctxt *authctxt)
498{
499 int i;
500 Gssctxt *gssctxt;
501 static int tries=0;
502
503 /* For now, we only make one attempt at this. We could try offering
504 * the server different GSSAPI OIDs until we get bored, I suppose.
505 */
506 if (tries++>0) return 0;
507
1e608e42 508 if (datafellows & SSH_OLD_GSSAPI) return 0;
509
5598e598 510 gssctxt=xmalloc(sizeof(Gssctxt));
511
512 /* Initialise as much of our context as we can, so failures can be
513 * trapped before sending any packets.
514 */
515 ssh_gssapi_build_ctx(gssctxt);
516 if (ssh_gssapi_import_name(gssctxt,authctxt->host)) {
517 return(0);
518 }
519 authctxt->methoddata=(void *)gssctxt;
520
521 packet_start(SSH2_MSG_USERAUTH_REQUEST);
2e9d2d36 522 if(options.implicit && !(datafellows & SSH_BUG_GSS_EMPTYUSER)) {
523 packet_put_cstring("");
524 } else {
525 packet_put_cstring(authctxt->server_user);
526 }
5598e598 527 packet_put_cstring(authctxt->service);
528 packet_put_cstring(authctxt->method->name);
529
530 /* FIXME: This assumes that our current GSSAPI implementation
531 * supports all of the mechanisms listed in supported_mechs.
532 * This may not be the case - we should use something along
533 * the lines of the code in gss_genr to remove the ones that
534 * aren't supported */
535 packet_put_int(GSS_LAST_ENTRY);
536 for (i=0;i<GSS_LAST_ENTRY;i++) {
537 packet_put_string(supported_mechs[i].oid.elements,
538 supported_mechs[i].oid.length);
539 }
540 packet_send();
541 packet_write_wait();
542
543 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,&input_gssapi_response);
544 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,&input_gssapi_token);
545
546 return 1;
547}
548
549void
1e608e42 550input_gssapi_response(int type, u_int32_t plen, void *ctxt)
5598e598 551{
552 Authctxt *authctxt = ctxt;
553 Gssctxt *gssctxt;
554 OM_uint32 status,ms;
555 int oidlen;
556 char *oidv;
557 gss_buffer_desc send_tok;
558
559 if (authctxt == NULL)
560 fatal("input_gssapi_response: no authentication context");
561 gssctxt = authctxt->methoddata;
562
563 /* Setup our OID */
564 oidv=packet_get_string(&oidlen);
565 ssh_gssapi_set_oid_data(gssctxt,oidv,oidlen);
566
1e608e42 567 packet_check_eom();
5598e598 568
569 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
570 GSS_C_NO_BUFFER, &send_tok,
571 NULL);
572 if (GSS_ERROR(status)) {
573 /* Start again with next method on list */
574 debug("Trying to start again");
575 userauth(authctxt,NULL);
576 return;
577 }
578
579 /* We must have data to send */
580 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
581 packet_put_string(send_tok.value,send_tok.length);
582 packet_send();
583 packet_write_wait();
584 gss_release_buffer(&ms, &send_tok);
585}
586
587void
1e608e42 588input_gssapi_token(int type, u_int32_t plen, void *ctxt)
5598e598 589{
590 Authctxt *authctxt = ctxt;
591 Gssctxt *gssctxt;
592 gss_buffer_desc send_tok,recv_tok;
593 OM_uint32 status;
594
595 if (authctxt == NULL)
596 fatal("input_gssapi_response: no authentication context");
597 gssctxt = authctxt->methoddata;
598
599 recv_tok.value=packet_get_string(&recv_tok.length);
600
601 status=ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
602 &recv_tok, &send_tok, NULL);
603
1e608e42 604 packet_check_eom();
5598e598 605
606 if (GSS_ERROR(status)) {
607 /* Start again with the next method in the list */
608 userauth(authctxt,NULL);
609 return;
610 }
611
612 if (send_tok.length>0) {
613 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
614 packet_put_string(send_tok.value,send_tok.length);
615 packet_send();
616 packet_write_wait();
617 }
618
619 if (status == GSS_S_COMPLETE) {
620 /* If that succeeded, send a exchange complete message */
621 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
622 packet_send();
623 packet_write_wait();
624 }
625}
626
627int
628userauth_external(Authctxt *authctxt)
629{
630 static int attempt =0;
631
632 if (attempt++ >= 1)
633 return 0;
634
635 debug2("userauth_external");
636 packet_start(SSH2_MSG_USERAUTH_REQUEST);
2e9d2d36 637 if(options.implicit && !(datafellows & SSH_BUG_GSS_EMPTYUSER)) {
638 packet_put_cstring("");
639 } else {
640 packet_put_cstring(authctxt->server_user);
641 }
5598e598 642 packet_put_cstring(authctxt->service);
643 packet_put_cstring(authctxt->method->name);
644 packet_send();
645 packet_write_wait();
646 return 1;
647}
648#endif /* GSSAPI */
649
3c0ef626 650int
651userauth_none(Authctxt *authctxt)
652{
653 /* initial userauth request */
654 packet_start(SSH2_MSG_USERAUTH_REQUEST);
655 packet_put_cstring(authctxt->server_user);
656 packet_put_cstring(authctxt->service);
657 packet_put_cstring(authctxt->method->name);
658 packet_send();
659 return 1;
5598e598 660
3c0ef626 661}
662
663int
664userauth_passwd(Authctxt *authctxt)
665{
666 static int attempt = 0;
510132b6 667 char prompt[150];
3c0ef626 668 char *password;
669
670 if (attempt++ >= options.number_of_password_prompts)
671 return 0;
672
1e608e42 673 if (attempt != 1)
3c0ef626 674 error("Permission denied, please try again.");
675
676 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
677 authctxt->server_user, authctxt->host);
678 password = read_passphrase(prompt, 0);
679 packet_start(SSH2_MSG_USERAUTH_REQUEST);
680 packet_put_cstring(authctxt->server_user);
681 packet_put_cstring(authctxt->service);
682 packet_put_cstring(authctxt->method->name);
683 packet_put_char(0);
684 packet_put_cstring(password);
685 memset(password, 0, strlen(password));
686 xfree(password);
687 packet_add_padding(64);
688 packet_send();
510132b6 689
44a053a3 690 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
510132b6 691 &input_userauth_passwd_changereq);
692
3c0ef626 693 return 1;
694}
510132b6 695/*
696 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
697 */
698void
699input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
700{
701 Authctxt *authctxt = ctxt;
702 char *info, *lang, *password = NULL, *retype = NULL;
703 char prompt[150];
704
705 debug2("input_userauth_passwd_changereq");
706
707 if (authctxt == NULL)
708 fatal("input_userauth_passwd_changereq: "
709 "no authentication context");
710
711 info = packet_get_string(NULL);
712 lang = packet_get_string(NULL);
713 if (strlen(info) > 0)
714 log("%s", info);
715 xfree(info);
716 xfree(lang);
717 packet_start(SSH2_MSG_USERAUTH_REQUEST);
718 packet_put_cstring(authctxt->server_user);
719 packet_put_cstring(authctxt->service);
720 packet_put_cstring(authctxt->method->name);
721 packet_put_char(1); /* additional info */
44a053a3 722 snprintf(prompt, sizeof(prompt),
510132b6 723 "Enter %.30s@%.128s's old password: ",
724 authctxt->server_user, authctxt->host);
725 password = read_passphrase(prompt, 0);
726 packet_put_cstring(password);
727 memset(password, 0, strlen(password));
728 xfree(password);
729 password = NULL;
730 while (password == NULL) {
44a053a3 731 snprintf(prompt, sizeof(prompt),
510132b6 732 "Enter %.30s@%.128s's new password: ",
733 authctxt->server_user, authctxt->host);
734 password = read_passphrase(prompt, RP_ALLOW_EOF);
735 if (password == NULL) {
736 /* bail out */
737 return;
738 }
44a053a3 739 snprintf(prompt, sizeof(prompt),
510132b6 740 "Retype %.30s@%.128s's new password: ",
741 authctxt->server_user, authctxt->host);
742 retype = read_passphrase(prompt, 0);
743 if (strcmp(password, retype) != 0) {
744 memset(password, 0, strlen(password));
745 xfree(password);
746 log("Mismatch; try again, EOF to quit.");
747 password = NULL;
748 }
749 memset(retype, 0, strlen(retype));
750 xfree(retype);
751 }
752 packet_put_cstring(password);
753 memset(password, 0, strlen(password));
754 xfree(password);
755 packet_add_padding(64);
756 packet_send();
44a053a3 757
758 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
510132b6 759 &input_userauth_passwd_changereq);
760}
3c0ef626 761
762static void
763clear_auth_state(Authctxt *authctxt)
764{
765 /* XXX clear authentication state */
510132b6 766 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, NULL);
767
3c0ef626 768 if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
769 debug3("clear_auth_state: key_free %p", authctxt->last_key);
770 key_free(authctxt->last_key);
771 }
772 authctxt->last_key = NULL;
773 authctxt->last_key_hint = -2;
774 authctxt->last_key_sign = NULL;
775}
776
777static int
778sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
779{
780 Buffer b;
781 u_char *blob, *signature;
1e608e42 782 u_int bloblen, slen;
3c0ef626 783 int skip = 0;
784 int ret = -1;
785 int have_sig = 1;
786
787 debug3("sign_and_send_pubkey");
788
789 if (key_to_blob(k, &blob, &bloblen) == 0) {
790 /* we cannot handle this key */
791 debug3("sign_and_send_pubkey: cannot handle key");
792 return 0;
793 }
794 /* data to be signed */
795 buffer_init(&b);
796 if (datafellows & SSH_OLD_SESSIONID) {
797 buffer_append(&b, session_id2, session_id2_len);
798 skip = session_id2_len;
799 } else {
800 buffer_put_string(&b, session_id2, session_id2_len);
801 skip = buffer_len(&b);
802 }
803 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
804 buffer_put_cstring(&b, authctxt->server_user);
805 buffer_put_cstring(&b,
806 datafellows & SSH_BUG_PKSERVICE ?
807 "ssh-userauth" :
808 authctxt->service);
809 if (datafellows & SSH_BUG_PKAUTH) {
810 buffer_put_char(&b, have_sig);
811 } else {
812 buffer_put_cstring(&b, authctxt->method->name);
813 buffer_put_char(&b, have_sig);
814 buffer_put_cstring(&b, key_ssh_name(k));
815 }
816 buffer_put_string(&b, blob, bloblen);
817
818 /* generate signature */
819 ret = (*sign_callback)(authctxt, k, &signature, &slen,
820 buffer_ptr(&b), buffer_len(&b));
821 if (ret == -1) {
822 xfree(blob);
823 buffer_free(&b);
824 return 0;
825 }
826#ifdef DEBUG_PK
827 buffer_dump(&b);
828#endif
829 if (datafellows & SSH_BUG_PKSERVICE) {
830 buffer_clear(&b);
831 buffer_append(&b, session_id2, session_id2_len);
832 skip = session_id2_len;
833 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
834 buffer_put_cstring(&b, authctxt->server_user);
835 buffer_put_cstring(&b, authctxt->service);
836 buffer_put_cstring(&b, authctxt->method->name);
837 buffer_put_char(&b, have_sig);
838 if (!(datafellows & SSH_BUG_PKAUTH))
839 buffer_put_cstring(&b, key_ssh_name(k));
840 buffer_put_string(&b, blob, bloblen);
841 }
842 xfree(blob);
843
844 /* append signature */
845 buffer_put_string(&b, signature, slen);
846 xfree(signature);
847
848 /* skip session id and packet type */
849 if (buffer_len(&b) < skip + 1)
850 fatal("userauth_pubkey: internal error");
851 buffer_consume(&b, skip + 1);
852
853 /* put remaining data from buffer into packet */
854 packet_start(SSH2_MSG_USERAUTH_REQUEST);
855 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
856 buffer_free(&b);
857 packet_send();
858
859 return 1;
860}
861
862static int
863send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
864 int hint)
865{
866 u_char *blob;
1e608e42 867 u_int bloblen, have_sig = 0;
3c0ef626 868
869 debug3("send_pubkey_test");
870
871 if (key_to_blob(k, &blob, &bloblen) == 0) {
872 /* we cannot handle this key */
873 debug3("send_pubkey_test: cannot handle key");
874 return 0;
875 }
876 /* register callback for USERAUTH_PK_OK message */
877 authctxt->last_key_sign = sign_callback;
878 authctxt->last_key_hint = hint;
879 authctxt->last_key = k;
880 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
881
882 packet_start(SSH2_MSG_USERAUTH_REQUEST);
883 packet_put_cstring(authctxt->server_user);
884 packet_put_cstring(authctxt->service);
885 packet_put_cstring(authctxt->method->name);
886 packet_put_char(have_sig);
887 if (!(datafellows & SSH_BUG_PKAUTH))
888 packet_put_cstring(key_ssh_name(k));
889 packet_put_string(blob, bloblen);
890 xfree(blob);
891 packet_send();
892 return 1;
893}
894
895static Key *
896load_identity_file(char *filename)
897{
898 Key *private;
899 char prompt[300], *passphrase;
900 int quit, i;
901 struct stat st;
902
903 if (stat(filename, &st) < 0) {
904 debug3("no such identity: %s", filename);
905 return NULL;
906 }
907 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
908 if (private == NULL) {
909 if (options.batch_mode)
910 return NULL;
911 snprintf(prompt, sizeof prompt,
1e608e42 912 "Enter passphrase for key '%.100s': ", filename);
3c0ef626 913 for (i = 0; i < options.number_of_password_prompts; i++) {
914 passphrase = read_passphrase(prompt, 0);
915 if (strcmp(passphrase, "") != 0) {
916 private = key_load_private_type(KEY_UNSPEC, filename,
917 passphrase, NULL);
918 quit = 0;
919 } else {
920 debug2("no passphrase given, try next key");
921 quit = 1;
922 }
923 memset(passphrase, 0, strlen(passphrase));
924 xfree(passphrase);
925 if (private != NULL || quit)
926 break;
927 debug2("bad passphrase given, try again...");
928 }
929 }
930 return private;
931}
932
933static int
1e608e42 934identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
935 u_char *data, u_int datalen)
3c0ef626 936{
937 Key *private;
938 int idx, ret;
939
940 idx = authctxt->last_key_hint;
941 if (idx < 0)
942 return -1;
943
944 /* private key is stored in external hardware */
1e608e42 945 if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
3c0ef626 946 return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
947
948 private = load_identity_file(options.identity_files[idx]);
949 if (private == NULL)
950 return -1;
951 ret = key_sign(private, sigp, lenp, data, datalen);
952 key_free(private);
953 return ret;
954}
955
956static int
1e608e42 957agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
958 u_char *data, u_int datalen)
3c0ef626 959{
960 return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
961}
962
963static int
1e608e42 964key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
965 u_char *data, u_int datalen)
3c0ef626 966{
967 return key_sign(key, sigp, lenp, data, datalen);
968}
969
970static int
971userauth_pubkey_agent(Authctxt *authctxt)
972{
973 static int called = 0;
974 int ret = 0;
975 char *comment;
976 Key *k;
977
978 if (called == 0) {
979 if (ssh_get_num_identities(authctxt->agent, 2) == 0)
980 debug2("userauth_pubkey_agent: no keys at all");
981 called = 1;
982 }
983 k = ssh_get_next_identity(authctxt->agent, &comment, 2);
984 if (k == NULL) {
985 debug2("userauth_pubkey_agent: no more keys");
986 } else {
987 debug("userauth_pubkey_agent: testing agent key %s", comment);
988 xfree(comment);
989 ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
990 if (ret == 0)
991 key_free(k);
992 }
993 if (ret == 0)
994 debug2("userauth_pubkey_agent: no message sent");
995 return ret;
996}
997
998int
999userauth_pubkey(Authctxt *authctxt)
1000{
1001 static int idx = 0;
1002 int sent = 0;
1003 Key *key;
1004 char *filename;
1005
1006 if (authctxt->agent != NULL) {
1007 do {
1008 sent = userauth_pubkey_agent(authctxt);
1e608e42 1009 } while (!sent && authctxt->agent->howmany > 0);
3c0ef626 1010 }
1011 while (!sent && idx < options.num_identity_files) {
1012 key = options.identity_keys[idx];
1013 filename = options.identity_files[idx];
1014 if (key == NULL) {
1015 debug("try privkey: %s", filename);
1016 key = load_identity_file(filename);
1017 if (key != NULL) {
1018 sent = sign_and_send_pubkey(authctxt, key,
1019 key_sign_cb);
1020 key_free(key);
1021 }
1022 } else if (key->type != KEY_RSA1) {
1023 debug("try pubkey: %s", filename);
1024 sent = send_pubkey_test(authctxt, key,
1025 identity_sign_cb, idx);
1026 }
1027 idx++;
1028 }
1029 return sent;
1030}
1031
1032/*
1033 * Send userauth request message specifying keyboard-interactive method.
1034 */
1035int
1036userauth_kbdint(Authctxt *authctxt)
1037{
1038 static int attempt = 0;
1039
1040 if (attempt++ >= options.number_of_password_prompts)
1041 return 0;
1042 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1043 if (attempt > 1 && !authctxt->info_req_seen) {
1044 debug3("userauth_kbdint: disable: no info_req_seen");
1045 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1046 return 0;
1047 }
1048
1049 debug2("userauth_kbdint");
1050 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1051 packet_put_cstring(authctxt->server_user);
1052 packet_put_cstring(authctxt->service);
1053 packet_put_cstring(authctxt->method->name);
1054 packet_put_cstring(""); /* lang */
1055 packet_put_cstring(options.kbd_interactive_devices ?
1056 options.kbd_interactive_devices : "");
1057 packet_send();
1058
1059 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1060 return 1;
1061}
1062
1063/*
1064 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1065 */
1066void
1e608e42 1067input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
3c0ef626 1068{
1069 Authctxt *authctxt = ctxt;
1070 char *name, *inst, *lang, *prompt, *response;
1071 u_int num_prompts, i;
1072 int echo = 0;
1073
1074 debug2("input_userauth_info_req");
1075
1076 if (authctxt == NULL)
1077 fatal("input_userauth_info_req: no authentication context");
1078
1079 authctxt->info_req_seen = 1;
1080
1081 name = packet_get_string(NULL);
1082 inst = packet_get_string(NULL);
1083 lang = packet_get_string(NULL);
1084 if (strlen(name) > 0)
1085 log("%s", name);
1086 if (strlen(inst) > 0)
1087 log("%s", inst);
1088 xfree(name);
1089 xfree(inst);
1090 xfree(lang);
1091
1092 num_prompts = packet_get_int();
1093 /*
1094 * Begin to build info response packet based on prompts requested.
1095 * We commit to providing the correct number of responses, so if
1096 * further on we run into a problem that prevents this, we have to
1097 * be sure and clean this up and send a correct error response.
1098 */
1099 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1100 packet_put_int(num_prompts);
1101
1102 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1103 for (i = 0; i < num_prompts; i++) {
1104 prompt = packet_get_string(NULL);
1105 echo = packet_get_char();
1106
1107 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1108
1109 packet_put_cstring(response);
1110 memset(response, 0, strlen(response));
1111 xfree(response);
1112 xfree(prompt);
1113 }
1e608e42 1114 packet_check_eom(); /* done with parsing incoming message. */
3c0ef626 1115
1116 packet_add_padding(64);
1117 packet_send();
1118}
1119
44a053a3 1120static int
276b07a3 1121ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
44a053a3 1122 u_char *data, u_int datalen)
1123{
1124 Buffer b;
1125 struct stat st;
1126 pid_t pid;
1127 int to[2], from[2], status, version = 2;
1128
1129 debug("ssh_keysign called");
1130
1131 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1132 error("ssh_keysign: no installed: %s", strerror(errno));
1133 return -1;
1134 }
1135 if (fflush(stdout) != 0)
1136 error("ssh_keysign: fflush: %s", strerror(errno));
1137 if (pipe(to) < 0) {
1138 error("ssh_keysign: pipe: %s", strerror(errno));
1139 return -1;
1140 }
1141 if (pipe(from) < 0) {
1142 error("ssh_keysign: pipe: %s", strerror(errno));
1143 return -1;
1144 }
1145 if ((pid = fork()) < 0) {
1146 error("ssh_keysign: fork: %s", strerror(errno));
1147 return -1;
1148 }
1149 if (pid == 0) {
1150 seteuid(getuid());
1151 setuid(getuid());
1152 close(from[0]);
1153 if (dup2(from[1], STDOUT_FILENO) < 0)
1154 fatal("ssh_keysign: dup2: %s", strerror(errno));
1155 close(to[1]);
1156 if (dup2(to[0], STDIN_FILENO) < 0)
1157 fatal("ssh_keysign: dup2: %s", strerror(errno));
1158 close(from[1]);
1159 close(to[0]);
1160 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1161 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1162 strerror(errno));
1163 }
1164 close(from[1]);
1165 close(to[0]);
1166
1167 buffer_init(&b);
1168 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1169 buffer_put_string(&b, data, datalen);
1170 msg_send(to[1], version, &b);
1171
1172 if (msg_recv(from[0], &b) < 0) {
1173 error("ssh_keysign: no reply");
1174 buffer_clear(&b);
1175 return -1;
1176 }
1177 close(from[0]);
1178 close(to[1]);
1179
1180 while (waitpid(pid, &status, 0) < 0)
1181 if (errno != EINTR)
1182 break;
1183
1184 if (buffer_get_char(&b) != version) {
1185 error("ssh_keysign: bad version");
1186 buffer_clear(&b);
1187 return -1;
1188 }
1189 *sigp = buffer_get_string(&b, lenp);
1190 buffer_clear(&b);
1191
1192 return 0;
1193}
1194
3c0ef626 1195int
1196userauth_hostbased(Authctxt *authctxt)
1197{
1198 Key *private = NULL;
44a053a3 1199 Sensitive *sensitive = authctxt->sensitive;
3c0ef626 1200 Buffer b;
1201 u_char *signature, *blob;
1202 char *chost, *pkalg, *p;
1203 const char *service;
1204 u_int blen, slen;
1205 int ok, i, len, found = 0;
1206
1207 /* check for a useful key */
44a053a3 1208 for (i = 0; i < sensitive->nkeys; i++) {
1209 private = sensitive->keys[i];
3c0ef626 1210 if (private && private->type != KEY_RSA1) {
1211 found = 1;
1212 /* we take and free the key */
44a053a3 1213 sensitive->keys[i] = NULL;
3c0ef626 1214 break;
1215 }
1216 }
1217 if (!found) {
1218 debug("userauth_hostbased: no more client hostkeys");
1219 return 0;
1220 }
1221 if (key_to_blob(private, &blob, &blen) == 0) {
1222 key_free(private);
1223 return 0;
1224 }
1225 /* figure out a name for the client host */
1226 p = get_local_name(packet_get_connection_in());
1227 if (p == NULL) {
1228 error("userauth_hostbased: cannot get local ipaddr/name");
1229 key_free(private);
1230 return 0;
1231 }
1232 len = strlen(p) + 2;
1233 chost = xmalloc(len);
1234 strlcpy(chost, p, len);
1235 strlcat(chost, ".", len);
1236 debug2("userauth_hostbased: chost %s", chost);
1237
1238 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1239 authctxt->service;
1240 pkalg = xstrdup(key_ssh_name(private));
1241 buffer_init(&b);
1242 /* construct data */
1243 buffer_put_string(&b, session_id2, session_id2_len);
1244 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1245 buffer_put_cstring(&b, authctxt->server_user);
1246 buffer_put_cstring(&b, service);
1247 buffer_put_cstring(&b, authctxt->method->name);
1248 buffer_put_cstring(&b, pkalg);
1249 buffer_put_string(&b, blob, blen);
1250 buffer_put_cstring(&b, chost);
1251 buffer_put_cstring(&b, authctxt->local_user);
1252#ifdef DEBUG_PK
1253 buffer_dump(&b);
1254#endif
44a053a3 1255 if (sensitive->external_keysign)
1256 ok = ssh_keysign(private, &signature, &slen,
1257 buffer_ptr(&b), buffer_len(&b));
1258 else
1259 ok = key_sign(private, &signature, &slen,
1260 buffer_ptr(&b), buffer_len(&b));
3c0ef626 1261 key_free(private);
1262 buffer_free(&b);
1263 if (ok != 0) {
1264 error("key_sign failed");
1265 xfree(chost);
1266 xfree(pkalg);
1267 return 0;
1268 }
1269 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1270 packet_put_cstring(authctxt->server_user);
1271 packet_put_cstring(authctxt->service);
1272 packet_put_cstring(authctxt->method->name);
1273 packet_put_cstring(pkalg);
1274 packet_put_string(blob, blen);
1275 packet_put_cstring(chost);
1276 packet_put_cstring(authctxt->local_user);
1277 packet_put_string(signature, slen);
1278 memset(signature, 's', slen);
1279 xfree(signature);
1280 xfree(chost);
1281 xfree(pkalg);
1282
1283 packet_send();
1284 return 1;
1285}
1286
1287/* find auth method */
1288
1289/*
1290 * given auth method name, if configurable options permit this method fill
1291 * in auth_ident field and return true, otherwise return false.
1292 */
1293static int
1294authmethod_is_enabled(Authmethod *method)
1295{
1296 if (method == NULL)
1297 return 0;
1298 /* return false if options indicate this method is disabled */
1299 if (method->enabled == NULL || *method->enabled == 0)
1300 return 0;
1301 /* return false if batch mode is enabled but method needs interactive mode */
1302 if (method->batch_flag != NULL && *method->batch_flag != 0)
1303 return 0;
1304 return 1;
1305}
1306
1307static Authmethod *
1308authmethod_lookup(const char *name)
1309{
1310 Authmethod *method = NULL;
1311 if (name != NULL)
1312 for (method = authmethods; method->name != NULL; method++)
1313 if (strcmp(name, method->name) == 0)
1314 return method;
1315 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1316 return NULL;
1317}
1318
1319/* XXX internal state */
1320static Authmethod *current = NULL;
1321static char *supported = NULL;
1322static char *preferred = NULL;
276b07a3 1323
3c0ef626 1324/*
1325 * Given the authentication method list sent by the server, return the
1326 * next method we should try. If the server initially sends a nil list,
1327 * use a built-in default list.
1328 */
1329static Authmethod *
1330authmethod_get(char *authlist)
1331{
1332
1333 char *name = NULL;
1e608e42 1334 u_int next;
3c0ef626 1335
1336 /* Use a suitable default if we're passed a nil list. */
1337 if (authlist == NULL || strlen(authlist) == 0)
1338 authlist = options.preferred_authentications;
1339
1340 if (supported == NULL || strcmp(authlist, supported) != 0) {
1341 debug3("start over, passed a different list %s", authlist);
1342 if (supported != NULL)
1343 xfree(supported);
1344 supported = xstrdup(authlist);
1345 preferred = options.preferred_authentications;
1346 debug3("preferred %s", preferred);
1347 current = NULL;
1348 } else if (current != NULL && authmethod_is_enabled(current))
1349 return current;
1350
1351 for (;;) {
1352 if ((name = match_list(preferred, supported, &next)) == NULL) {
1353 debug("no more auth methods to try");
1354 current = NULL;
1355 return NULL;
1356 }
1357 preferred += next;
1358 debug3("authmethod_lookup %s", name);
1359 debug3("remaining preferred: %s", preferred);
1360 if ((current = authmethod_lookup(name)) != NULL &&
1361 authmethod_is_enabled(current)) {
1362 debug3("authmethod_is_enabled %s", name);
1363 debug("next auth method to try is %s", name);
1364 return current;
1365 }
1366 }
1367}
1368
3c0ef626 1369static char *
1370authmethods_get(void)
1371{
1372 Authmethod *method = NULL;
1e608e42 1373 Buffer b;
1374 char *list;
3c0ef626 1375
1e608e42 1376 buffer_init(&b);
3c0ef626 1377 for (method = authmethods; method->name != NULL; method++) {
1378 if (authmethod_is_enabled(method)) {
1e608e42 1379 if (buffer_len(&b) > 0)
1380 buffer_append(&b, ",", 1);
1381 buffer_append(&b, method->name, strlen(method->name));
3c0ef626 1382 }
1383 }
1e608e42 1384 buffer_append(&b, "\0", 1);
1385 list = xstrdup(buffer_ptr(&b));
1386 buffer_free(&b);
1387 return list;
3c0ef626 1388}
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