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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"
44a053a3 26RCSID("$OpenBSD: sshconnect2.c,v 1.104 2002/06/19 00:27:55 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}
364void
1e608e42 365input_userauth_error(int type, u_int32_t seq, void *ctxt)
3c0ef626 366{
367 fatal("input_userauth_error: bad message during authentication: "
368 "type %d", type);
369}
370void
1e608e42 371input_userauth_banner(int type, u_int32_t seq, void *ctxt)
3c0ef626 372{
373 char *msg, *lang;
374 debug3("input_userauth_banner");
375 msg = packet_get_string(NULL);
376 lang = packet_get_string(NULL);
377 fprintf(stderr, "%s", msg);
378 xfree(msg);
379 xfree(lang);
380}
381void
1e608e42 382input_userauth_success(int type, u_int32_t seq, void *ctxt)
3c0ef626 383{
384 Authctxt *authctxt = ctxt;
385 if (authctxt == NULL)
386 fatal("input_userauth_success: no authentication context");
387 if (authctxt->authlist)
388 xfree(authctxt->authlist);
5598e598 389 if (authctxt->methoddata)
390 xfree(authctxt->methoddata);
3c0ef626 391 clear_auth_state(authctxt);
392 authctxt->success = 1; /* break out */
393}
394void
1e608e42 395input_userauth_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 396{
397 Authctxt *authctxt = ctxt;
398 char *authlist = NULL;
399 int partial;
400
401 if (authctxt == NULL)
402 fatal("input_userauth_failure: no authentication context");
403
404 authlist = packet_get_string(NULL);
405 partial = packet_get_char();
1e608e42 406 packet_check_eom();
3c0ef626 407
408 if (partial != 0)
409 log("Authenticated with partial success.");
410 debug("authentications that can continue: %s", authlist);
411
412 clear_auth_state(authctxt);
413 userauth(authctxt, authlist);
414}
415void
1e608e42 416input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
3c0ef626 417{
418 Authctxt *authctxt = ctxt;
419 Key *key = NULL;
420 Buffer b;
1e608e42 421 int pktype, sent = 0;
422 u_int alen, blen;
423 char *pkalg, *fp;
424 u_char *pkblob;
3c0ef626 425
426 if (authctxt == NULL)
427 fatal("input_userauth_pk_ok: no authentication context");
428 if (datafellows & SSH_BUG_PKOK) {
429 /* this is similar to SSH_BUG_PKAUTH */
430 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
431 pkblob = packet_get_string(&blen);
432 buffer_init(&b);
433 buffer_append(&b, pkblob, blen);
434 pkalg = buffer_get_string(&b, &alen);
435 buffer_free(&b);
436 } else {
437 pkalg = packet_get_string(&alen);
438 pkblob = packet_get_string(&blen);
439 }
1e608e42 440 packet_check_eom();
3c0ef626 441
442 debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
443 pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
444
445 do {
446 if (authctxt->last_key == NULL ||
447 authctxt->last_key_sign == NULL) {
448 debug("no last key or no sign cb");
449 break;
450 }
1e608e42 451 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
3c0ef626 452 debug("unknown pkalg %s", pkalg);
453 break;
454 }
455 if ((key = key_from_blob(pkblob, blen)) == NULL) {
456 debug("no key from blob. pkalg %s", pkalg);
457 break;
458 }
510132b6 459 if (key->type != pktype) {
1e608e42 460 error("input_userauth_pk_ok: type mismatch "
461 "for decoded key (received %d, expected %d)",
44a053a3 462 key->type, pktype);
1e608e42 463 break;
464 }
3c0ef626 465 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
466 debug2("input_userauth_pk_ok: fp %s", fp);
467 xfree(fp);
468 if (!key_equal(key, authctxt->last_key)) {
469 debug("key != last_key");
470 break;
471 }
472 sent = sign_and_send_pubkey(authctxt, key,
473 authctxt->last_key_sign);
1e608e42 474 } while (0);
3c0ef626 475
476 if (key != NULL)
477 key_free(key);
478 xfree(pkalg);
479 xfree(pkblob);
480
481 /* unregister */
482 clear_auth_state(authctxt);
483 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
484
485 /* try another method if we did not send a packet*/
486 if (sent == 0)
487 userauth(authctxt, NULL);
488
489}
490
5598e598 491#ifdef GSSAPI
492int
493userauth_gssapi(Authctxt *authctxt)
494{
495 int i;
496 Gssctxt *gssctxt;
497 static int tries=0;
498
499 /* For now, we only make one attempt at this. We could try offering
500 * the server different GSSAPI OIDs until we get bored, I suppose.
501 */
502 if (tries++>0) return 0;
503
1e608e42 504 if (datafellows & SSH_OLD_GSSAPI) return 0;
505
5598e598 506 gssctxt=xmalloc(sizeof(Gssctxt));
507
508 /* Initialise as much of our context as we can, so failures can be
509 * trapped before sending any packets.
510 */
511 ssh_gssapi_build_ctx(gssctxt);
512 if (ssh_gssapi_import_name(gssctxt,authctxt->host)) {
513 return(0);
514 }
515 authctxt->methoddata=(void *)gssctxt;
516
517 packet_start(SSH2_MSG_USERAUTH_REQUEST);
2e9d2d36 518 if(options.implicit && !(datafellows & SSH_BUG_GSS_EMPTYUSER)) {
519 packet_put_cstring("");
520 } else {
521 packet_put_cstring(authctxt->server_user);
522 }
5598e598 523 packet_put_cstring(authctxt->service);
524 packet_put_cstring(authctxt->method->name);
525
526 /* FIXME: This assumes that our current GSSAPI implementation
527 * supports all of the mechanisms listed in supported_mechs.
528 * This may not be the case - we should use something along
529 * the lines of the code in gss_genr to remove the ones that
530 * aren't supported */
531 packet_put_int(GSS_LAST_ENTRY);
532 for (i=0;i<GSS_LAST_ENTRY;i++) {
533 packet_put_string(supported_mechs[i].oid.elements,
534 supported_mechs[i].oid.length);
535 }
536 packet_send();
537 packet_write_wait();
538
539 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,&input_gssapi_response);
540 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,&input_gssapi_token);
541
542 return 1;
543}
544
545void
1e608e42 546input_gssapi_response(int type, u_int32_t plen, void *ctxt)
5598e598 547{
548 Authctxt *authctxt = ctxt;
549 Gssctxt *gssctxt;
550 OM_uint32 status,ms;
551 int oidlen;
552 char *oidv;
553 gss_buffer_desc send_tok;
554
555 if (authctxt == NULL)
556 fatal("input_gssapi_response: no authentication context");
557 gssctxt = authctxt->methoddata;
558
559 /* Setup our OID */
560 oidv=packet_get_string(&oidlen);
561 ssh_gssapi_set_oid_data(gssctxt,oidv,oidlen);
562
1e608e42 563 packet_check_eom();
5598e598 564
565 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
566 GSS_C_NO_BUFFER, &send_tok,
567 NULL);
568 if (GSS_ERROR(status)) {
569 /* Start again with next method on list */
570 debug("Trying to start again");
571 userauth(authctxt,NULL);
572 return;
573 }
574
575 /* We must have data to send */
576 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
577 packet_put_string(send_tok.value,send_tok.length);
578 packet_send();
579 packet_write_wait();
580 gss_release_buffer(&ms, &send_tok);
581}
582
583void
1e608e42 584input_gssapi_token(int type, u_int32_t plen, void *ctxt)
5598e598 585{
586 Authctxt *authctxt = ctxt;
587 Gssctxt *gssctxt;
588 gss_buffer_desc send_tok,recv_tok;
589 OM_uint32 status;
590
591 if (authctxt == NULL)
592 fatal("input_gssapi_response: no authentication context");
593 gssctxt = authctxt->methoddata;
594
595 recv_tok.value=packet_get_string(&recv_tok.length);
596
597 status=ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
598 &recv_tok, &send_tok, NULL);
599
1e608e42 600 packet_check_eom();
5598e598 601
602 if (GSS_ERROR(status)) {
603 /* Start again with the next method in the list */
604 userauth(authctxt,NULL);
605 return;
606 }
607
608 if (send_tok.length>0) {
609 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
610 packet_put_string(send_tok.value,send_tok.length);
611 packet_send();
612 packet_write_wait();
613 }
614
615 if (status == GSS_S_COMPLETE) {
616 /* If that succeeded, send a exchange complete message */
617 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
618 packet_send();
619 packet_write_wait();
620 }
621}
622
623int
624userauth_external(Authctxt *authctxt)
625{
626 static int attempt =0;
627
628 if (attempt++ >= 1)
629 return 0;
630
631 debug2("userauth_external");
632 packet_start(SSH2_MSG_USERAUTH_REQUEST);
2e9d2d36 633 if(options.implicit && !(datafellows & SSH_BUG_GSS_EMPTYUSER)) {
634 packet_put_cstring("");
635 } else {
636 packet_put_cstring(authctxt->server_user);
637 }
5598e598 638 packet_put_cstring(authctxt->service);
639 packet_put_cstring(authctxt->method->name);
640 packet_send();
641 packet_write_wait();
642 return 1;
643}
644#endif /* GSSAPI */
645
3c0ef626 646int
647userauth_none(Authctxt *authctxt)
648{
649 /* initial userauth request */
650 packet_start(SSH2_MSG_USERAUTH_REQUEST);
651 packet_put_cstring(authctxt->server_user);
652 packet_put_cstring(authctxt->service);
653 packet_put_cstring(authctxt->method->name);
654 packet_send();
655 return 1;
5598e598 656
3c0ef626 657}
658
659int
660userauth_passwd(Authctxt *authctxt)
661{
662 static int attempt = 0;
510132b6 663 char prompt[150];
3c0ef626 664 char *password;
665
666 if (attempt++ >= options.number_of_password_prompts)
667 return 0;
668
1e608e42 669 if (attempt != 1)
3c0ef626 670 error("Permission denied, please try again.");
671
672 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
673 authctxt->server_user, authctxt->host);
674 password = read_passphrase(prompt, 0);
675 packet_start(SSH2_MSG_USERAUTH_REQUEST);
676 packet_put_cstring(authctxt->server_user);
677 packet_put_cstring(authctxt->service);
678 packet_put_cstring(authctxt->method->name);
679 packet_put_char(0);
680 packet_put_cstring(password);
681 memset(password, 0, strlen(password));
682 xfree(password);
683 packet_add_padding(64);
684 packet_send();
510132b6 685
44a053a3 686 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
510132b6 687 &input_userauth_passwd_changereq);
688
3c0ef626 689 return 1;
690}
510132b6 691/*
692 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
693 */
694void
695input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
696{
697 Authctxt *authctxt = ctxt;
698 char *info, *lang, *password = NULL, *retype = NULL;
699 char prompt[150];
700
701 debug2("input_userauth_passwd_changereq");
702
703 if (authctxt == NULL)
704 fatal("input_userauth_passwd_changereq: "
705 "no authentication context");
706
707 info = packet_get_string(NULL);
708 lang = packet_get_string(NULL);
709 if (strlen(info) > 0)
710 log("%s", info);
711 xfree(info);
712 xfree(lang);
713 packet_start(SSH2_MSG_USERAUTH_REQUEST);
714 packet_put_cstring(authctxt->server_user);
715 packet_put_cstring(authctxt->service);
716 packet_put_cstring(authctxt->method->name);
717 packet_put_char(1); /* additional info */
44a053a3 718 snprintf(prompt, sizeof(prompt),
510132b6 719 "Enter %.30s@%.128s's old password: ",
720 authctxt->server_user, authctxt->host);
721 password = read_passphrase(prompt, 0);
722 packet_put_cstring(password);
723 memset(password, 0, strlen(password));
724 xfree(password);
725 password = NULL;
726 while (password == NULL) {
44a053a3 727 snprintf(prompt, sizeof(prompt),
510132b6 728 "Enter %.30s@%.128s's new password: ",
729 authctxt->server_user, authctxt->host);
730 password = read_passphrase(prompt, RP_ALLOW_EOF);
731 if (password == NULL) {
732 /* bail out */
733 return;
734 }
44a053a3 735 snprintf(prompt, sizeof(prompt),
510132b6 736 "Retype %.30s@%.128s's new password: ",
737 authctxt->server_user, authctxt->host);
738 retype = read_passphrase(prompt, 0);
739 if (strcmp(password, retype) != 0) {
740 memset(password, 0, strlen(password));
741 xfree(password);
742 log("Mismatch; try again, EOF to quit.");
743 password = NULL;
744 }
745 memset(retype, 0, strlen(retype));
746 xfree(retype);
747 }
748 packet_put_cstring(password);
749 memset(password, 0, strlen(password));
750 xfree(password);
751 packet_add_padding(64);
752 packet_send();
44a053a3 753
754 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
510132b6 755 &input_userauth_passwd_changereq);
756}
3c0ef626 757
758static void
759clear_auth_state(Authctxt *authctxt)
760{
761 /* XXX clear authentication state */
510132b6 762 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, NULL);
763
3c0ef626 764 if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
765 debug3("clear_auth_state: key_free %p", authctxt->last_key);
766 key_free(authctxt->last_key);
767 }
768 authctxt->last_key = NULL;
769 authctxt->last_key_hint = -2;
770 authctxt->last_key_sign = NULL;
771}
772
773static int
774sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
775{
776 Buffer b;
777 u_char *blob, *signature;
1e608e42 778 u_int bloblen, slen;
3c0ef626 779 int skip = 0;
780 int ret = -1;
781 int have_sig = 1;
782
783 debug3("sign_and_send_pubkey");
784
785 if (key_to_blob(k, &blob, &bloblen) == 0) {
786 /* we cannot handle this key */
787 debug3("sign_and_send_pubkey: cannot handle key");
788 return 0;
789 }
790 /* data to be signed */
791 buffer_init(&b);
792 if (datafellows & SSH_OLD_SESSIONID) {
793 buffer_append(&b, session_id2, session_id2_len);
794 skip = session_id2_len;
795 } else {
796 buffer_put_string(&b, session_id2, session_id2_len);
797 skip = buffer_len(&b);
798 }
799 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
800 buffer_put_cstring(&b, authctxt->server_user);
801 buffer_put_cstring(&b,
802 datafellows & SSH_BUG_PKSERVICE ?
803 "ssh-userauth" :
804 authctxt->service);
805 if (datafellows & SSH_BUG_PKAUTH) {
806 buffer_put_char(&b, have_sig);
807 } else {
808 buffer_put_cstring(&b, authctxt->method->name);
809 buffer_put_char(&b, have_sig);
810 buffer_put_cstring(&b, key_ssh_name(k));
811 }
812 buffer_put_string(&b, blob, bloblen);
813
814 /* generate signature */
815 ret = (*sign_callback)(authctxt, k, &signature, &slen,
816 buffer_ptr(&b), buffer_len(&b));
817 if (ret == -1) {
818 xfree(blob);
819 buffer_free(&b);
820 return 0;
821 }
822#ifdef DEBUG_PK
823 buffer_dump(&b);
824#endif
825 if (datafellows & SSH_BUG_PKSERVICE) {
826 buffer_clear(&b);
827 buffer_append(&b, session_id2, session_id2_len);
828 skip = session_id2_len;
829 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
830 buffer_put_cstring(&b, authctxt->server_user);
831 buffer_put_cstring(&b, authctxt->service);
832 buffer_put_cstring(&b, authctxt->method->name);
833 buffer_put_char(&b, have_sig);
834 if (!(datafellows & SSH_BUG_PKAUTH))
835 buffer_put_cstring(&b, key_ssh_name(k));
836 buffer_put_string(&b, blob, bloblen);
837 }
838 xfree(blob);
839
840 /* append signature */
841 buffer_put_string(&b, signature, slen);
842 xfree(signature);
843
844 /* skip session id and packet type */
845 if (buffer_len(&b) < skip + 1)
846 fatal("userauth_pubkey: internal error");
847 buffer_consume(&b, skip + 1);
848
849 /* put remaining data from buffer into packet */
850 packet_start(SSH2_MSG_USERAUTH_REQUEST);
851 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
852 buffer_free(&b);
853 packet_send();
854
855 return 1;
856}
857
858static int
859send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
860 int hint)
861{
862 u_char *blob;
1e608e42 863 u_int bloblen, have_sig = 0;
3c0ef626 864
865 debug3("send_pubkey_test");
866
867 if (key_to_blob(k, &blob, &bloblen) == 0) {
868 /* we cannot handle this key */
869 debug3("send_pubkey_test: cannot handle key");
870 return 0;
871 }
872 /* register callback for USERAUTH_PK_OK message */
873 authctxt->last_key_sign = sign_callback;
874 authctxt->last_key_hint = hint;
875 authctxt->last_key = k;
876 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
877
878 packet_start(SSH2_MSG_USERAUTH_REQUEST);
879 packet_put_cstring(authctxt->server_user);
880 packet_put_cstring(authctxt->service);
881 packet_put_cstring(authctxt->method->name);
882 packet_put_char(have_sig);
883 if (!(datafellows & SSH_BUG_PKAUTH))
884 packet_put_cstring(key_ssh_name(k));
885 packet_put_string(blob, bloblen);
886 xfree(blob);
887 packet_send();
888 return 1;
889}
890
891static Key *
892load_identity_file(char *filename)
893{
894 Key *private;
895 char prompt[300], *passphrase;
896 int quit, i;
897 struct stat st;
898
899 if (stat(filename, &st) < 0) {
900 debug3("no such identity: %s", filename);
901 return NULL;
902 }
903 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
904 if (private == NULL) {
905 if (options.batch_mode)
906 return NULL;
907 snprintf(prompt, sizeof prompt,
1e608e42 908 "Enter passphrase for key '%.100s': ", filename);
3c0ef626 909 for (i = 0; i < options.number_of_password_prompts; i++) {
910 passphrase = read_passphrase(prompt, 0);
911 if (strcmp(passphrase, "") != 0) {
912 private = key_load_private_type(KEY_UNSPEC, filename,
913 passphrase, NULL);
914 quit = 0;
915 } else {
916 debug2("no passphrase given, try next key");
917 quit = 1;
918 }
919 memset(passphrase, 0, strlen(passphrase));
920 xfree(passphrase);
921 if (private != NULL || quit)
922 break;
923 debug2("bad passphrase given, try again...");
924 }
925 }
926 return private;
927}
928
929static int
1e608e42 930identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
931 u_char *data, u_int datalen)
3c0ef626 932{
933 Key *private;
934 int idx, ret;
935
936 idx = authctxt->last_key_hint;
937 if (idx < 0)
938 return -1;
939
940 /* private key is stored in external hardware */
1e608e42 941 if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
3c0ef626 942 return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
943
944 private = load_identity_file(options.identity_files[idx]);
945 if (private == NULL)
946 return -1;
947 ret = key_sign(private, sigp, lenp, data, datalen);
948 key_free(private);
949 return ret;
950}
951
952static int
1e608e42 953agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
954 u_char *data, u_int datalen)
3c0ef626 955{
956 return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
957}
958
959static int
1e608e42 960key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
961 u_char *data, u_int datalen)
3c0ef626 962{
963 return key_sign(key, sigp, lenp, data, datalen);
964}
965
966static int
967userauth_pubkey_agent(Authctxt *authctxt)
968{
969 static int called = 0;
970 int ret = 0;
971 char *comment;
972 Key *k;
973
974 if (called == 0) {
975 if (ssh_get_num_identities(authctxt->agent, 2) == 0)
976 debug2("userauth_pubkey_agent: no keys at all");
977 called = 1;
978 }
979 k = ssh_get_next_identity(authctxt->agent, &comment, 2);
980 if (k == NULL) {
981 debug2("userauth_pubkey_agent: no more keys");
982 } else {
983 debug("userauth_pubkey_agent: testing agent key %s", comment);
984 xfree(comment);
985 ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
986 if (ret == 0)
987 key_free(k);
988 }
989 if (ret == 0)
990 debug2("userauth_pubkey_agent: no message sent");
991 return ret;
992}
993
994int
995userauth_pubkey(Authctxt *authctxt)
996{
997 static int idx = 0;
998 int sent = 0;
999 Key *key;
1000 char *filename;
1001
1002 if (authctxt->agent != NULL) {
1003 do {
1004 sent = userauth_pubkey_agent(authctxt);
1e608e42 1005 } while (!sent && authctxt->agent->howmany > 0);
3c0ef626 1006 }
1007 while (!sent && idx < options.num_identity_files) {
1008 key = options.identity_keys[idx];
1009 filename = options.identity_files[idx];
1010 if (key == NULL) {
1011 debug("try privkey: %s", filename);
1012 key = load_identity_file(filename);
1013 if (key != NULL) {
1014 sent = sign_and_send_pubkey(authctxt, key,
1015 key_sign_cb);
1016 key_free(key);
1017 }
1018 } else if (key->type != KEY_RSA1) {
1019 debug("try pubkey: %s", filename);
1020 sent = send_pubkey_test(authctxt, key,
1021 identity_sign_cb, idx);
1022 }
1023 idx++;
1024 }
1025 return sent;
1026}
1027
1028/*
1029 * Send userauth request message specifying keyboard-interactive method.
1030 */
1031int
1032userauth_kbdint(Authctxt *authctxt)
1033{
1034 static int attempt = 0;
1035
1036 if (attempt++ >= options.number_of_password_prompts)
1037 return 0;
1038 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1039 if (attempt > 1 && !authctxt->info_req_seen) {
1040 debug3("userauth_kbdint: disable: no info_req_seen");
1041 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1042 return 0;
1043 }
1044
1045 debug2("userauth_kbdint");
1046 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1047 packet_put_cstring(authctxt->server_user);
1048 packet_put_cstring(authctxt->service);
1049 packet_put_cstring(authctxt->method->name);
1050 packet_put_cstring(""); /* lang */
1051 packet_put_cstring(options.kbd_interactive_devices ?
1052 options.kbd_interactive_devices : "");
1053 packet_send();
1054
1055 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1056 return 1;
1057}
1058
1059/*
1060 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1061 */
1062void
1e608e42 1063input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
3c0ef626 1064{
1065 Authctxt *authctxt = ctxt;
1066 char *name, *inst, *lang, *prompt, *response;
1067 u_int num_prompts, i;
1068 int echo = 0;
1069
1070 debug2("input_userauth_info_req");
1071
1072 if (authctxt == NULL)
1073 fatal("input_userauth_info_req: no authentication context");
1074
1075 authctxt->info_req_seen = 1;
1076
1077 name = packet_get_string(NULL);
1078 inst = packet_get_string(NULL);
1079 lang = packet_get_string(NULL);
1080 if (strlen(name) > 0)
1081 log("%s", name);
1082 if (strlen(inst) > 0)
1083 log("%s", inst);
1084 xfree(name);
1085 xfree(inst);
1086 xfree(lang);
1087
1088 num_prompts = packet_get_int();
1089 /*
1090 * Begin to build info response packet based on prompts requested.
1091 * We commit to providing the correct number of responses, so if
1092 * further on we run into a problem that prevents this, we have to
1093 * be sure and clean this up and send a correct error response.
1094 */
1095 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1096 packet_put_int(num_prompts);
1097
1098 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1099 for (i = 0; i < num_prompts; i++) {
1100 prompt = packet_get_string(NULL);
1101 echo = packet_get_char();
1102
1103 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1104
1105 packet_put_cstring(response);
1106 memset(response, 0, strlen(response));
1107 xfree(response);
1108 xfree(prompt);
1109 }
1e608e42 1110 packet_check_eom(); /* done with parsing incoming message. */
3c0ef626 1111
1112 packet_add_padding(64);
1113 packet_send();
1114}
1115
44a053a3 1116static int
1117ssh_keysign(
1118 Key *key,
1119 u_char **sigp, u_int *lenp,
1120 u_char *data, u_int datalen)
1121{
1122 Buffer b;
1123 struct stat st;
1124 pid_t pid;
1125 int to[2], from[2], status, version = 2;
1126
1127 debug("ssh_keysign called");
1128
1129 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1130 error("ssh_keysign: no installed: %s", strerror(errno));
1131 return -1;
1132 }
1133 if (fflush(stdout) != 0)
1134 error("ssh_keysign: fflush: %s", strerror(errno));
1135 if (pipe(to) < 0) {
1136 error("ssh_keysign: pipe: %s", strerror(errno));
1137 return -1;
1138 }
1139 if (pipe(from) < 0) {
1140 error("ssh_keysign: pipe: %s", strerror(errno));
1141 return -1;
1142 }
1143 if ((pid = fork()) < 0) {
1144 error("ssh_keysign: fork: %s", strerror(errno));
1145 return -1;
1146 }
1147 if (pid == 0) {
1148 seteuid(getuid());
1149 setuid(getuid());
1150 close(from[0]);
1151 if (dup2(from[1], STDOUT_FILENO) < 0)
1152 fatal("ssh_keysign: dup2: %s", strerror(errno));
1153 close(to[1]);
1154 if (dup2(to[0], STDIN_FILENO) < 0)
1155 fatal("ssh_keysign: dup2: %s", strerror(errno));
1156 close(from[1]);
1157 close(to[0]);
1158 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1159 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1160 strerror(errno));
1161 }
1162 close(from[1]);
1163 close(to[0]);
1164
1165 buffer_init(&b);
1166 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1167 buffer_put_string(&b, data, datalen);
1168 msg_send(to[1], version, &b);
1169
1170 if (msg_recv(from[0], &b) < 0) {
1171 error("ssh_keysign: no reply");
1172 buffer_clear(&b);
1173 return -1;
1174 }
1175 close(from[0]);
1176 close(to[1]);
1177
1178 while (waitpid(pid, &status, 0) < 0)
1179 if (errno != EINTR)
1180 break;
1181
1182 if (buffer_get_char(&b) != version) {
1183 error("ssh_keysign: bad version");
1184 buffer_clear(&b);
1185 return -1;
1186 }
1187 *sigp = buffer_get_string(&b, lenp);
1188 buffer_clear(&b);
1189
1190 return 0;
1191}
1192
3c0ef626 1193int
1194userauth_hostbased(Authctxt *authctxt)
1195{
1196 Key *private = NULL;
44a053a3 1197 Sensitive *sensitive = authctxt->sensitive;
3c0ef626 1198 Buffer b;
1199 u_char *signature, *blob;
1200 char *chost, *pkalg, *p;
1201 const char *service;
1202 u_int blen, slen;
1203 int ok, i, len, found = 0;
1204
1205 /* check for a useful key */
44a053a3 1206 for (i = 0; i < sensitive->nkeys; i++) {
1207 private = sensitive->keys[i];
3c0ef626 1208 if (private && private->type != KEY_RSA1) {
1209 found = 1;
1210 /* we take and free the key */
44a053a3 1211 sensitive->keys[i] = NULL;
3c0ef626 1212 break;
1213 }
1214 }
1215 if (!found) {
1216 debug("userauth_hostbased: no more client hostkeys");
1217 return 0;
1218 }
1219 if (key_to_blob(private, &blob, &blen) == 0) {
1220 key_free(private);
1221 return 0;
1222 }
1223 /* figure out a name for the client host */
1224 p = get_local_name(packet_get_connection_in());
1225 if (p == NULL) {
1226 error("userauth_hostbased: cannot get local ipaddr/name");
1227 key_free(private);
1228 return 0;
1229 }
1230 len = strlen(p) + 2;
1231 chost = xmalloc(len);
1232 strlcpy(chost, p, len);
1233 strlcat(chost, ".", len);
1234 debug2("userauth_hostbased: chost %s", chost);
1235
1236 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1237 authctxt->service;
1238 pkalg = xstrdup(key_ssh_name(private));
1239 buffer_init(&b);
1240 /* construct data */
1241 buffer_put_string(&b, session_id2, session_id2_len);
1242 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1243 buffer_put_cstring(&b, authctxt->server_user);
1244 buffer_put_cstring(&b, service);
1245 buffer_put_cstring(&b, authctxt->method->name);
1246 buffer_put_cstring(&b, pkalg);
1247 buffer_put_string(&b, blob, blen);
1248 buffer_put_cstring(&b, chost);
1249 buffer_put_cstring(&b, authctxt->local_user);
1250#ifdef DEBUG_PK
1251 buffer_dump(&b);
1252#endif
44a053a3 1253 if (sensitive->external_keysign)
1254 ok = ssh_keysign(private, &signature, &slen,
1255 buffer_ptr(&b), buffer_len(&b));
1256 else
1257 ok = key_sign(private, &signature, &slen,
1258 buffer_ptr(&b), buffer_len(&b));
3c0ef626 1259 key_free(private);
1260 buffer_free(&b);
1261 if (ok != 0) {
1262 error("key_sign failed");
1263 xfree(chost);
1264 xfree(pkalg);
1265 return 0;
1266 }
1267 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1268 packet_put_cstring(authctxt->server_user);
1269 packet_put_cstring(authctxt->service);
1270 packet_put_cstring(authctxt->method->name);
1271 packet_put_cstring(pkalg);
1272 packet_put_string(blob, blen);
1273 packet_put_cstring(chost);
1274 packet_put_cstring(authctxt->local_user);
1275 packet_put_string(signature, slen);
1276 memset(signature, 's', slen);
1277 xfree(signature);
1278 xfree(chost);
1279 xfree(pkalg);
1280
1281 packet_send();
1282 return 1;
1283}
1284
1285/* find auth method */
1286
1287/*
1288 * given auth method name, if configurable options permit this method fill
1289 * in auth_ident field and return true, otherwise return false.
1290 */
1291static int
1292authmethod_is_enabled(Authmethod *method)
1293{
1294 if (method == NULL)
1295 return 0;
1296 /* return false if options indicate this method is disabled */
1297 if (method->enabled == NULL || *method->enabled == 0)
1298 return 0;
1299 /* return false if batch mode is enabled but method needs interactive mode */
1300 if (method->batch_flag != NULL && *method->batch_flag != 0)
1301 return 0;
1302 return 1;
1303}
1304
1305static Authmethod *
1306authmethod_lookup(const char *name)
1307{
1308 Authmethod *method = NULL;
1309 if (name != NULL)
1310 for (method = authmethods; method->name != NULL; method++)
1311 if (strcmp(name, method->name) == 0)
1312 return method;
1313 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1314 return NULL;
1315}
1316
1317/* XXX internal state */
1318static Authmethod *current = NULL;
1319static char *supported = NULL;
1320static char *preferred = NULL;
1321/*
1322 * Given the authentication method list sent by the server, return the
1323 * next method we should try. If the server initially sends a nil list,
1324 * use a built-in default list.
1325 */
1326static Authmethod *
1327authmethod_get(char *authlist)
1328{
1329
1330 char *name = NULL;
1e608e42 1331 u_int next;
3c0ef626 1332
1333 /* Use a suitable default if we're passed a nil list. */
1334 if (authlist == NULL || strlen(authlist) == 0)
1335 authlist = options.preferred_authentications;
1336
1337 if (supported == NULL || strcmp(authlist, supported) != 0) {
1338 debug3("start over, passed a different list %s", authlist);
1339 if (supported != NULL)
1340 xfree(supported);
1341 supported = xstrdup(authlist);
1342 preferred = options.preferred_authentications;
1343 debug3("preferred %s", preferred);
1344 current = NULL;
1345 } else if (current != NULL && authmethod_is_enabled(current))
1346 return current;
1347
1348 for (;;) {
1349 if ((name = match_list(preferred, supported, &next)) == NULL) {
1350 debug("no more auth methods to try");
1351 current = NULL;
1352 return NULL;
1353 }
1354 preferred += next;
1355 debug3("authmethod_lookup %s", name);
1356 debug3("remaining preferred: %s", preferred);
1357 if ((current = authmethod_lookup(name)) != NULL &&
1358 authmethod_is_enabled(current)) {
1359 debug3("authmethod_is_enabled %s", name);
1360 debug("next auth method to try is %s", name);
1361 return current;
1362 }
1363 }
1364}
1365
3c0ef626 1366static char *
1367authmethods_get(void)
1368{
1369 Authmethod *method = NULL;
1e608e42 1370 Buffer b;
1371 char *list;
3c0ef626 1372
1e608e42 1373 buffer_init(&b);
3c0ef626 1374 for (method = authmethods; method->name != NULL; method++) {
1375 if (authmethod_is_enabled(method)) {
1e608e42 1376 if (buffer_len(&b) > 0)
1377 buffer_append(&b, ",", 1);
1378 buffer_append(&b, method->name, strlen(method->name));
3c0ef626 1379 }
1380 }
1e608e42 1381 buffer_append(&b, "\0", 1);
1382 list = xstrdup(buffer_ptr(&b));
1383 buffer_free(&b);
1384 return list;
3c0ef626 1385}
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