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openssh-3.6.1p1-gssapi-20030416.diff from Simon
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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"
6a9b3198 26RCSID("$OpenBSD: sshconnect2.c,v 1.114 2003/04/01 10:22:21 markus 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"
f5799ae1 48#include "msg.h"
49#include "pathnames.h"
3c0ef626 50
898296fe 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;
898296fe 84#ifdef GSSAPI
85 char *orig, *gss;
86 int len;
87#endif
3c0ef626 88
89 xxx_host = host;
90 xxx_hostaddr = hostaddr;
91
898296fe 92#ifdef GSSAPI
93 /* Add the GSSAPI mechanisms currently supported on this client to
3e196425 94 * the key exchange algorithm proposal */
898296fe 95 orig = myproposal[PROPOSAL_KEX_ALGS];
96 gss = ssh_gssapi_client_mechanisms(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);
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] =
41b2f314 118 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib,none";
3c0ef626 119 } else {
120 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
41b2f314 121 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib";
3c0ef626 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)
e9a17296 128 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
3c0ef626 129 options.hostkeyalgorithms;
130
898296fe 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
3c0ef626 141 /* start key exchange */
142 kex = kex_setup(myproposal);
6a9b3198 143 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
144 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
898296fe 145#ifdef GSSAPI
146 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client;
147#endif
3c0ef626 148 kex->client_version_string=client_version_string;
149 kex->server_version_string=server_version_string;
150 kex->verify_host_key=&verify_host_key_callback;
898296fe 151 kex->host=host;
152#ifdef GSSAPI
153 kex->options.gss_deleg_creds=options.gss_deleg_creds;
154#endif
3c0ef626 155 xxx_kex = kex;
156
157 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
158
159 session_id2 = kex->session_id;
160 session_id2_len = kex->session_id_len;
161
162#ifdef DEBUG_KEXDH
163 /* send 1st encrypted/maced/compressed message */
164 packet_start(SSH2_MSG_IGNORE);
165 packet_put_cstring("markus");
166 packet_send();
167 packet_write_wait();
168#endif
3c0ef626 169}
170
171/*
172 * Authenticate user
173 */
174
175typedef struct Authctxt Authctxt;
176typedef struct Authmethod Authmethod;
177
178typedef int sign_cb_fn(
179 Authctxt *authctxt, Key *key,
e9a17296 180 u_char **sigp, u_int *lenp, u_char *data, u_int datalen);
3c0ef626 181
182struct Authctxt {
183 const char *server_user;
184 const char *local_user;
185 const char *host;
186 const char *service;
187 Authmethod *method;
188 int success;
189 char *authlist;
190 /* pubkey */
191 Key *last_key;
192 sign_cb_fn *last_key_sign;
193 int last_key_hint;
194 AuthenticationConnection *agent;
195 /* hostbased */
f5799ae1 196 Sensitive *sensitive;
3c0ef626 197 /* kbd-interactive */
198 int info_req_seen;
898296fe 199 /* generic */
200 void *methoddata;
3c0ef626 201};
202struct Authmethod {
203 char *name; /* string to compare against server's list */
204 int (*userauth)(Authctxt *authctxt);
205 int *enabled; /* flag in option struct that enables method */
206 int *batch_flag; /* flag in option struct that disables method */
207};
208
e9a17296 209void input_userauth_success(int, u_int32_t, void *);
210void input_userauth_failure(int, u_int32_t, void *);
211void input_userauth_banner(int, u_int32_t, void *);
212void input_userauth_error(int, u_int32_t, void *);
213void input_userauth_info_req(int, u_int32_t, void *);
214void input_userauth_pk_ok(int, u_int32_t, void *);
700318f3 215void input_userauth_passwd_changereq(int, u_int32_t, void *);
3c0ef626 216
e9a17296 217int userauth_none(Authctxt *);
218int userauth_pubkey(Authctxt *);
219int userauth_passwd(Authctxt *);
220int userauth_kbdint(Authctxt *);
221int userauth_hostbased(Authctxt *);
3c0ef626 222
898296fe 223#ifdef GSSAPI
224int userauth_external(Authctxt *authctxt);
225int userauth_gssapi(Authctxt *authctxt);
3e196425 226void input_gssapi_response(int type, u_int32_t, void *);
227void input_gssapi_token(int type, u_int32_t, void *);
228void input_gssapi_hash(int type, u_int32_t, void *);
898296fe 229void input_gssapi_error(int, u_int32_t, void *);
3e196425 230void input_gssapi_errtok(int, u_int32_t, void *);
898296fe 231#endif
232
e9a17296 233void userauth(Authctxt *, char *);
3c0ef626 234
235static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
236static void clear_auth_state(Authctxt *);
237
238static Authmethod *authmethod_get(char *authlist);
239static Authmethod *authmethod_lookup(const char *name);
240static char *authmethods_get(void);
241
242Authmethod authmethods[] = {
898296fe 243#ifdef GSSAPI
244 {"external-keyx",
245 userauth_external,
246 &options.gss_authentication,
247 NULL},
248 {"gssapi",
249 userauth_gssapi,
250 &options.gss_authentication,
251 NULL},
252#endif
3c0ef626 253 {"hostbased",
254 userauth_hostbased,
255 &options.hostbased_authentication,
256 NULL},
257 {"publickey",
258 userauth_pubkey,
259 &options.pubkey_authentication,
260 NULL},
261 {"keyboard-interactive",
262 userauth_kbdint,
263 &options.kbd_interactive_authentication,
264 &options.batch_mode},
265 {"password",
266 userauth_passwd,
267 &options.password_authentication,
268 &options.batch_mode},
269 {"none",
270 userauth_none,
271 NULL,
272 NULL},
273 {NULL, NULL, NULL, NULL}
274};
275
276void
277ssh_userauth2(const char *local_user, const char *server_user, char *host,
f5799ae1 278 Sensitive *sensitive)
3c0ef626 279{
280 Authctxt authctxt;
281 int type;
3c0ef626 282
283 if (options.challenge_response_authentication)
284 options.kbd_interactive_authentication = 1;
285
3c0ef626 286 packet_start(SSH2_MSG_SERVICE_REQUEST);
287 packet_put_cstring("ssh-userauth");
288 packet_send();
6a9b3198 289 debug("SSH2_MSG_SERVICE_REQUEST sent");
3c0ef626 290 packet_write_wait();
e9a17296 291 type = packet_read();
6a9b3198 292 if (type != SSH2_MSG_SERVICE_ACCEPT)
293 fatal("Server denied authentication request: %d", type);
3c0ef626 294 if (packet_remaining() > 0) {
e9a17296 295 char *reply = packet_get_string(NULL);
6a9b3198 296 debug2("service_accept: %s", reply);
3c0ef626 297 xfree(reply);
298 } else {
6a9b3198 299 debug2("buggy server: service_accept w/o service");
3c0ef626 300 }
e9a17296 301 packet_check_eom();
6a9b3198 302 debug("SSH2_MSG_SERVICE_ACCEPT received");
3c0ef626 303
304 if (options.preferred_authentications == NULL)
305 options.preferred_authentications = authmethods_get();
306
307 /* setup authentication context */
308 memset(&authctxt, 0, sizeof(authctxt));
309 authctxt.agent = ssh_get_authentication_connection();
310 authctxt.server_user = server_user;
311 authctxt.local_user = local_user;
312 authctxt.host = host;
313 authctxt.service = "ssh-connection"; /* service name */
314 authctxt.success = 0;
315 authctxt.method = authmethod_lookup("none");
316 authctxt.authlist = NULL;
898296fe 317 authctxt.methoddata = NULL;
f5799ae1 318 authctxt.sensitive = sensitive;
3c0ef626 319 authctxt.info_req_seen = 0;
320 if (authctxt.method == NULL)
321 fatal("ssh_userauth2: internal error: cannot send userauth none request");
322
323 /* initial userauth request */
324 userauth_none(&authctxt);
325
326 dispatch_init(&input_userauth_error);
327 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
328 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
329 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
330 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
331
332 if (authctxt.agent != NULL)
333 ssh_close_authentication_connection(authctxt.agent);
334
6a9b3198 335 debug("Authentication succeeded (%s).", authctxt.method->name);
3c0ef626 336}
337void
338userauth(Authctxt *authctxt, char *authlist)
339{
898296fe 340 if (authctxt->methoddata!=NULL) {
341 xfree(authctxt->methoddata);
342 authctxt->methoddata=NULL;
343 }
344
3c0ef626 345 if (authlist == NULL) {
346 authlist = authctxt->authlist;
347 } else {
348 if (authctxt->authlist)
349 xfree(authctxt->authlist);
350 authctxt->authlist = authlist;
351 }
352 for (;;) {
353 Authmethod *method = authmethod_get(authlist);
354 if (method == NULL)
355 fatal("Permission denied (%s).", authlist);
356 authctxt->method = method;
357 if (method->userauth(authctxt) != 0) {
358 debug2("we sent a %s packet, wait for reply", method->name);
359 break;
360 } else {
361 debug2("we did not send a packet, disable method");
362 method->enabled = NULL;
363 }
364 }
365}
680cee3b 366
3c0ef626 367void
e9a17296 368input_userauth_error(int type, u_int32_t seq, void *ctxt)
3c0ef626 369{
370 fatal("input_userauth_error: bad message during authentication: "
371 "type %d", type);
372}
680cee3b 373
3c0ef626 374void
e9a17296 375input_userauth_banner(int type, u_int32_t seq, void *ctxt)
3c0ef626 376{
377 char *msg, *lang;
378 debug3("input_userauth_banner");
379 msg = packet_get_string(NULL);
380 lang = packet_get_string(NULL);
381 fprintf(stderr, "%s", msg);
382 xfree(msg);
383 xfree(lang);
384}
680cee3b 385
3c0ef626 386void
e9a17296 387input_userauth_success(int type, u_int32_t seq, void *ctxt)
3c0ef626 388{
389 Authctxt *authctxt = ctxt;
390 if (authctxt == NULL)
391 fatal("input_userauth_success: no authentication context");
392 if (authctxt->authlist)
393 xfree(authctxt->authlist);
898296fe 394 if (authctxt->methoddata)
395 xfree(authctxt->methoddata);
3c0ef626 396 clear_auth_state(authctxt);
397 authctxt->success = 1; /* break out */
398}
680cee3b 399
3c0ef626 400void
e9a17296 401input_userauth_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 402{
403 Authctxt *authctxt = ctxt;
404 char *authlist = NULL;
405 int partial;
406
407 if (authctxt == NULL)
408 fatal("input_userauth_failure: no authentication context");
409
410 authlist = packet_get_string(NULL);
411 partial = packet_get_char();
e9a17296 412 packet_check_eom();
3c0ef626 413
414 if (partial != 0)
415 log("Authenticated with partial success.");
6a9b3198 416 debug("Authentications that can continue: %s", authlist);
3c0ef626 417
418 clear_auth_state(authctxt);
419 userauth(authctxt, authlist);
420}
421void
e9a17296 422input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
3c0ef626 423{
424 Authctxt *authctxt = ctxt;
425 Key *key = NULL;
426 Buffer b;
e9a17296 427 int pktype, sent = 0;
428 u_int alen, blen;
429 char *pkalg, *fp;
430 u_char *pkblob;
3c0ef626 431
432 if (authctxt == NULL)
433 fatal("input_userauth_pk_ok: no authentication context");
434 if (datafellows & SSH_BUG_PKOK) {
435 /* this is similar to SSH_BUG_PKAUTH */
436 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
437 pkblob = packet_get_string(&blen);
438 buffer_init(&b);
439 buffer_append(&b, pkblob, blen);
440 pkalg = buffer_get_string(&b, &alen);
441 buffer_free(&b);
442 } else {
443 pkalg = packet_get_string(&alen);
444 pkblob = packet_get_string(&blen);
445 }
e9a17296 446 packet_check_eom();
3c0ef626 447
6a9b3198 448 debug("Server accepts key: pkalg %s blen %u lastkey %p hint %d",
3c0ef626 449 pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
450
451 do {
452 if (authctxt->last_key == NULL ||
453 authctxt->last_key_sign == NULL) {
454 debug("no last key or no sign cb");
455 break;
456 }
e9a17296 457 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
3c0ef626 458 debug("unknown pkalg %s", pkalg);
459 break;
460 }
461 if ((key = key_from_blob(pkblob, blen)) == NULL) {
462 debug("no key from blob. pkalg %s", pkalg);
463 break;
464 }
700318f3 465 if (key->type != pktype) {
e9a17296 466 error("input_userauth_pk_ok: type mismatch "
467 "for decoded key (received %d, expected %d)",
f5799ae1 468 key->type, pktype);
e9a17296 469 break;
470 }
3c0ef626 471 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
472 debug2("input_userauth_pk_ok: fp %s", fp);
473 xfree(fp);
474 if (!key_equal(key, authctxt->last_key)) {
475 debug("key != last_key");
476 break;
477 }
478 sent = sign_and_send_pubkey(authctxt, key,
479 authctxt->last_key_sign);
e9a17296 480 } while (0);
3c0ef626 481
482 if (key != NULL)
483 key_free(key);
484 xfree(pkalg);
485 xfree(pkblob);
486
487 /* unregister */
488 clear_auth_state(authctxt);
489 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
490
41b2f314 491 /* try another method if we did not send a packet */
3c0ef626 492 if (sent == 0)
493 userauth(authctxt, NULL);
494
495}
496
898296fe 497#ifdef GSSAPI
498int
499userauth_gssapi(Authctxt *authctxt)
500{
501 Gssctxt *gssctxt = NULL;
502 static gss_OID_set supported = NULL;
503 static int mech=0;
504 OM_uint32 min;
505 int ok=0;
506
507 /* Things work better if we send one mechanism at a time, rather
3e196425 508 * than them all at once. This means that if we fail at some point
509 * in the middle of a negotiation, we can come back and try something
510 * different. */
898296fe 511
512 if (datafellows & SSH_OLD_GSSAPI) return 0;
513
514 /* Before we offer a mechanism, check that we can support it. Don't
3e196425 515 * bother trying to get credentials - as the standard fallback will
516 * deal with that kind of failure.
517 */
898296fe 518
519 if (supported==NULL) gss_indicate_mechs(&min, &supported);
520
521 while (mech<supported->count && !ok) {
522 if (gssctxt) ssh_gssapi_delete_ctx(&gssctxt);
523 ssh_gssapi_build_ctx(&gssctxt);
524 ssh_gssapi_set_oid(gssctxt,&supported->elements[mech]);
525
526 /* The DER encoding below only works for lengths<128,
3e196425 527 * so check this here
528 */
898296fe 529 if (supported->elements[mech].length<128 &&
530 !GSS_ERROR(ssh_gssapi_import_name(gssctxt,
531 authctxt->host))) {
3e196425 532 ok = 1; /* Mechanism works */
898296fe 533 } else {
534 mech++;
535 }
536 }
537
538 if (!ok) return 0;
539
540 authctxt->methoddata=(void *)gssctxt;
541
542 packet_start(SSH2_MSG_USERAUTH_REQUEST);
543 packet_put_cstring(authctxt->server_user);
544 packet_put_cstring(authctxt->service);
545 packet_put_cstring(authctxt->method->name);
546
547 packet_put_int(1);
548
549 /* The newest gsskeyex draft stipulates that OIDs should
3e196425 550 * be DER encoded, so we need to add the object type and
551 * length information back on */
898296fe 552 if (datafellows & SSH_BUG_GSSAPI_BER) {
553 packet_put_string(supported->elements[mech].elements,
554 supported->elements[mech].length);
555 } else {
556 packet_put_int((supported->elements[mech].length)+2);
557 packet_put_char(0x06);
558 packet_put_char(supported->elements[mech].length);
559 packet_put_raw(supported->elements[mech].elements,
560 supported->elements[mech].length);
561 }
562
563 packet_send();
564 packet_write_wait();
565
566 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,&input_gssapi_response);
567 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,&input_gssapi_token);
568 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR,&input_gssapi_error);
3e196425 569 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK,&input_gssapi_errtok);
898296fe 570
571 mech++; /* Move along to next candidate */
572
573 return 1;
574}
575
576void
577input_gssapi_response(int type, u_int32_t plen, void *ctxt)
578{
579 Authctxt *authctxt = ctxt;
580 Gssctxt *gssctxt;
581 OM_uint32 status,ms;
582 int oidlen;
583 char *oidv;
584 gss_buffer_desc send_tok;
585
586 if (authctxt == NULL)
587 fatal("input_gssapi_response: no authentication context");
588 gssctxt = authctxt->methoddata;
589
590 /* Setup our OID */
591 oidv=packet_get_string(&oidlen);
592
593 if (datafellows & SSH_BUG_GSSAPI_BER) {
594 if (!ssh_gssapi_check_oid(gssctxt,oidv,oidlen)) {
595 fatal("Server returned different OID than expected");
596 }
597 ssh_gssapi_set_oid_data(gssctxt,oidv,oidlen);
598 } else {
599 if(oidv[0]!=0x06 || oidv[1]!=oidlen-2) {
600 debug("Badly encoded mechanism OID received");
601 clear_auth_state(authctxt);
602 userauth(authctxt,NULL);
603 return;
604 }
605 if (!ssh_gssapi_check_oid(gssctxt,oidv+2,oidlen-2)) {
606 fatal("Server returned different OID than expected");
607 }
608 ssh_gssapi_set_oid_data(gssctxt,oidv+2,oidlen-2);
609 }
610
611 packet_check_eom();
612
613 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
614 GSS_C_NO_BUFFER, &send_tok,
615 NULL);
616 if (GSS_ERROR(status)) {
3e196425 617 if (send_tok.length>0) {
618 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
619 packet_put_string(send_tok.value,send_tok.length);
620 packet_send();
621 packet_write_wait();
622 }
898296fe 623 /* Start again with next method on list */
624 debug("Trying to start again");
625 clear_auth_state(authctxt);
626 userauth(authctxt,NULL);
627 return;
628 }
629
630 /* We must have data to send */
631 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
632 packet_put_string(send_tok.value,send_tok.length);
633 packet_send();
634 packet_write_wait();
635 gss_release_buffer(&ms, &send_tok);
636}
637
638void
639input_gssapi_token(int type, u_int32_t plen, void *ctxt)
640{
641 Authctxt *authctxt = ctxt;
642 Gssctxt *gssctxt;
643 gss_buffer_desc send_tok,recv_tok;
644 OM_uint32 status;
645
646 if (authctxt == NULL)
647 fatal("input_gssapi_response: no authentication context");
648 gssctxt = authctxt->methoddata;
649
650 recv_tok.value=packet_get_string(&recv_tok.length);
651
652 status=ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
653 &recv_tok, &send_tok, NULL);
654
655 packet_check_eom();
656
657 if (GSS_ERROR(status)) {
3e196425 658 if (send_tok.length>0) {
659 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
660 packet_put_string(send_tok.value,send_tok.length);
661 packet_send();
662 packet_write_wait();
663 }
898296fe 664 /* Start again with the next method in the list */
665 clear_auth_state(authctxt);
666 userauth(authctxt,NULL);
667 return;
668 }
669
670 if (send_tok.length>0) {
671 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
672 packet_put_string(send_tok.value,send_tok.length);
673 packet_send();
674 packet_write_wait();
675 }
676
677 if (status == GSS_S_COMPLETE) {
678 /* If that succeeded, send a exchange complete message */
679 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
680 packet_send();
681 packet_write_wait();
682 }
683}
684
3e196425 685void
686input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
687{
688 Authctxt *authctxt = ctxt;
689 Gssctxt *gssctxt;
690 gss_buffer_desc send_tok,recv_tok;
691 OM_uint32 status;
692
693 if (authctxt == NULL)
694 fatal("input_gssapi_response: no authentication context");
695 gssctxt = authctxt->methoddata;
696
697 recv_tok.value=packet_get_string(&recv_tok.length);
698
699 /* Stick it into GSSAPI and see what it says */
700 status=ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
701 &recv_tok, &send_tok, NULL);
702
703 packet_check_eom();
704
705 /* We can't send a packet to the server */
706
707 /* The draft says that we should wait for the server to fail
708 * before starting the next authentication. So, we clear the
709 * state, but don't do anything else */
710 clear_auth_state(authctxt);
711 return;
712}
713
898296fe 714void
715input_gssapi_error(int type, u_int32_t plen, void *ctxt)
716{
717 OM_uint32 maj,min;
718 char *msg;
719 char *lang;
720
721 maj=packet_get_int();
722 min=packet_get_int();
723 msg=packet_get_string(NULL);
724 lang=packet_get_string(NULL);
725
726 packet_check_eom();
727
728 fprintf(stderr, "Server GSSAPI Error:\n%s\n", msg);
729 xfree(msg);
730 xfree(lang);
731}
732
733int
734userauth_external(Authctxt *authctxt)
735{
736 static int attempt =0;
737
738 if (attempt++ >= 1)
739 return 0;
740
741 debug2("userauth_external");
742 packet_start(SSH2_MSG_USERAUTH_REQUEST);
743 packet_put_cstring(authctxt->server_user);
744 packet_put_cstring(authctxt->service);
745 packet_put_cstring(authctxt->method->name);
746 packet_send();
747 packet_write_wait();
748 return 1;
749}
750#endif /* GSSAPI */
751
3c0ef626 752int
753userauth_none(Authctxt *authctxt)
754{
755 /* initial userauth request */
756 packet_start(SSH2_MSG_USERAUTH_REQUEST);
757 packet_put_cstring(authctxt->server_user);
758 packet_put_cstring(authctxt->service);
759 packet_put_cstring(authctxt->method->name);
760 packet_send();
761 return 1;
898296fe 762
3c0ef626 763}
764
765int
766userauth_passwd(Authctxt *authctxt)
767{
768 static int attempt = 0;
700318f3 769 char prompt[150];
3c0ef626 770 char *password;
771
772 if (attempt++ >= options.number_of_password_prompts)
773 return 0;
774
e9a17296 775 if (attempt != 1)
3c0ef626 776 error("Permission denied, please try again.");
777
778 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
779 authctxt->server_user, authctxt->host);
780 password = read_passphrase(prompt, 0);
781 packet_start(SSH2_MSG_USERAUTH_REQUEST);
782 packet_put_cstring(authctxt->server_user);
783 packet_put_cstring(authctxt->service);
784 packet_put_cstring(authctxt->method->name);
785 packet_put_char(0);
786 packet_put_cstring(password);
787 memset(password, 0, strlen(password));
788 xfree(password);
789 packet_add_padding(64);
790 packet_send();
700318f3 791
f5799ae1 792 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
700318f3 793 &input_userauth_passwd_changereq);
794
3c0ef626 795 return 1;
796}
700318f3 797/*
798 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
799 */
800void
801input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
802{
803 Authctxt *authctxt = ctxt;
804 char *info, *lang, *password = NULL, *retype = NULL;
805 char prompt[150];
806
807 debug2("input_userauth_passwd_changereq");
808
809 if (authctxt == NULL)
810 fatal("input_userauth_passwd_changereq: "
811 "no authentication context");
812
813 info = packet_get_string(NULL);
814 lang = packet_get_string(NULL);
815 if (strlen(info) > 0)
816 log("%s", info);
817 xfree(info);
818 xfree(lang);
819 packet_start(SSH2_MSG_USERAUTH_REQUEST);
820 packet_put_cstring(authctxt->server_user);
821 packet_put_cstring(authctxt->service);
822 packet_put_cstring(authctxt->method->name);
823 packet_put_char(1); /* additional info */
f5799ae1 824 snprintf(prompt, sizeof(prompt),
700318f3 825 "Enter %.30s@%.128s's old password: ",
826 authctxt->server_user, authctxt->host);
827 password = read_passphrase(prompt, 0);
828 packet_put_cstring(password);
829 memset(password, 0, strlen(password));
830 xfree(password);
831 password = NULL;
832 while (password == NULL) {
f5799ae1 833 snprintf(prompt, sizeof(prompt),
700318f3 834 "Enter %.30s@%.128s's new password: ",
835 authctxt->server_user, authctxt->host);
836 password = read_passphrase(prompt, RP_ALLOW_EOF);
837 if (password == NULL) {
838 /* bail out */
839 return;
840 }
f5799ae1 841 snprintf(prompt, sizeof(prompt),
700318f3 842 "Retype %.30s@%.128s's new password: ",
843 authctxt->server_user, authctxt->host);
844 retype = read_passphrase(prompt, 0);
845 if (strcmp(password, retype) != 0) {
846 memset(password, 0, strlen(password));
847 xfree(password);
848 log("Mismatch; try again, EOF to quit.");
849 password = NULL;
850 }
851 memset(retype, 0, strlen(retype));
852 xfree(retype);
853 }
854 packet_put_cstring(password);
855 memset(password, 0, strlen(password));
856 xfree(password);
857 packet_add_padding(64);
858 packet_send();
f5799ae1 859
860 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
700318f3 861 &input_userauth_passwd_changereq);
862}
3c0ef626 863
864static void
865clear_auth_state(Authctxt *authctxt)
866{
867 /* XXX clear authentication state */
700318f3 868 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, NULL);
898296fe 869#ifdef GSSAPI
870 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,NULL);
871 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN,NULL);
872 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR,NULL);
873#endif
874
3c0ef626 875 if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
876 debug3("clear_auth_state: key_free %p", authctxt->last_key);
877 key_free(authctxt->last_key);
878 }
879 authctxt->last_key = NULL;
880 authctxt->last_key_hint = -2;
881 authctxt->last_key_sign = NULL;
882}
883
884static int
885sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
886{
887 Buffer b;
888 u_char *blob, *signature;
e9a17296 889 u_int bloblen, slen;
3c0ef626 890 int skip = 0;
891 int ret = -1;
892 int have_sig = 1;
893
894 debug3("sign_and_send_pubkey");
895
896 if (key_to_blob(k, &blob, &bloblen) == 0) {
897 /* we cannot handle this key */
898 debug3("sign_and_send_pubkey: cannot handle key");
899 return 0;
900 }
901 /* data to be signed */
902 buffer_init(&b);
903 if (datafellows & SSH_OLD_SESSIONID) {
904 buffer_append(&b, session_id2, session_id2_len);
905 skip = session_id2_len;
906 } else {
907 buffer_put_string(&b, session_id2, session_id2_len);
908 skip = buffer_len(&b);
909 }
910 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
911 buffer_put_cstring(&b, authctxt->server_user);
912 buffer_put_cstring(&b,
913 datafellows & SSH_BUG_PKSERVICE ?
914 "ssh-userauth" :
915 authctxt->service);
916 if (datafellows & SSH_BUG_PKAUTH) {
917 buffer_put_char(&b, have_sig);
918 } else {
919 buffer_put_cstring(&b, authctxt->method->name);
920 buffer_put_char(&b, have_sig);
921 buffer_put_cstring(&b, key_ssh_name(k));
922 }
923 buffer_put_string(&b, blob, bloblen);
924
925 /* generate signature */
926 ret = (*sign_callback)(authctxt, k, &signature, &slen,
927 buffer_ptr(&b), buffer_len(&b));
928 if (ret == -1) {
929 xfree(blob);
930 buffer_free(&b);
931 return 0;
932 }
933#ifdef DEBUG_PK
934 buffer_dump(&b);
935#endif
936 if (datafellows & SSH_BUG_PKSERVICE) {
937 buffer_clear(&b);
938 buffer_append(&b, session_id2, session_id2_len);
939 skip = session_id2_len;
940 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
941 buffer_put_cstring(&b, authctxt->server_user);
942 buffer_put_cstring(&b, authctxt->service);
943 buffer_put_cstring(&b, authctxt->method->name);
944 buffer_put_char(&b, have_sig);
945 if (!(datafellows & SSH_BUG_PKAUTH))
946 buffer_put_cstring(&b, key_ssh_name(k));
947 buffer_put_string(&b, blob, bloblen);
948 }
949 xfree(blob);
950
951 /* append signature */
952 buffer_put_string(&b, signature, slen);
953 xfree(signature);
954
955 /* skip session id and packet type */
956 if (buffer_len(&b) < skip + 1)
957 fatal("userauth_pubkey: internal error");
958 buffer_consume(&b, skip + 1);
959
960 /* put remaining data from buffer into packet */
961 packet_start(SSH2_MSG_USERAUTH_REQUEST);
962 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
963 buffer_free(&b);
964 packet_send();
965
966 return 1;
967}
968
969static int
970send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
971 int hint)
972{
973 u_char *blob;
e9a17296 974 u_int bloblen, have_sig = 0;
3c0ef626 975
976 debug3("send_pubkey_test");
977
978 if (key_to_blob(k, &blob, &bloblen) == 0) {
979 /* we cannot handle this key */
980 debug3("send_pubkey_test: cannot handle key");
981 return 0;
982 }
983 /* register callback for USERAUTH_PK_OK message */
984 authctxt->last_key_sign = sign_callback;
985 authctxt->last_key_hint = hint;
986 authctxt->last_key = k;
987 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
988
989 packet_start(SSH2_MSG_USERAUTH_REQUEST);
990 packet_put_cstring(authctxt->server_user);
991 packet_put_cstring(authctxt->service);
992 packet_put_cstring(authctxt->method->name);
993 packet_put_char(have_sig);
994 if (!(datafellows & SSH_BUG_PKAUTH))
995 packet_put_cstring(key_ssh_name(k));
996 packet_put_string(blob, bloblen);
997 xfree(blob);
998 packet_send();
999 return 1;
1000}
1001
1002static Key *
1003load_identity_file(char *filename)
1004{
1005 Key *private;
1006 char prompt[300], *passphrase;
1007 int quit, i;
1008 struct stat st;
1009
1010 if (stat(filename, &st) < 0) {
1011 debug3("no such identity: %s", filename);
1012 return NULL;
1013 }
1014 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
1015 if (private == NULL) {
1016 if (options.batch_mode)
1017 return NULL;
1018 snprintf(prompt, sizeof prompt,
e9a17296 1019 "Enter passphrase for key '%.100s': ", filename);
3c0ef626 1020 for (i = 0; i < options.number_of_password_prompts; i++) {
1021 passphrase = read_passphrase(prompt, 0);
1022 if (strcmp(passphrase, "") != 0) {
1023 private = key_load_private_type(KEY_UNSPEC, filename,
1024 passphrase, NULL);
1025 quit = 0;
1026 } else {
1027 debug2("no passphrase given, try next key");
1028 quit = 1;
1029 }
1030 memset(passphrase, 0, strlen(passphrase));
1031 xfree(passphrase);
1032 if (private != NULL || quit)
1033 break;
1034 debug2("bad passphrase given, try again...");
1035 }
1036 }
1037 return private;
1038}
1039
1040static int
e9a17296 1041identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
1042 u_char *data, u_int datalen)
3c0ef626 1043{
1044 Key *private;
1045 int idx, ret;
1046
1047 idx = authctxt->last_key_hint;
1048 if (idx < 0)
1049 return -1;
1050
1051 /* private key is stored in external hardware */
e9a17296 1052 if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
3c0ef626 1053 return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
1054
1055 private = load_identity_file(options.identity_files[idx]);
1056 if (private == NULL)
1057 return -1;
1058 ret = key_sign(private, sigp, lenp, data, datalen);
1059 key_free(private);
1060 return ret;
1061}
1062
1063static int
e9a17296 1064agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
1065 u_char *data, u_int datalen)
3c0ef626 1066{
1067 return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
1068}
1069
1070static int
e9a17296 1071key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
1072 u_char *data, u_int datalen)
3c0ef626 1073{
1074 return key_sign(key, sigp, lenp, data, datalen);
1075}
1076
1077static int
1078userauth_pubkey_agent(Authctxt *authctxt)
1079{
1080 static int called = 0;
1081 int ret = 0;
1082 char *comment;
1083 Key *k;
1084
1085 if (called == 0) {
1086 if (ssh_get_num_identities(authctxt->agent, 2) == 0)
1087 debug2("userauth_pubkey_agent: no keys at all");
1088 called = 1;
1089 }
1090 k = ssh_get_next_identity(authctxt->agent, &comment, 2);
1091 if (k == NULL) {
1092 debug2("userauth_pubkey_agent: no more keys");
1093 } else {
6a9b3198 1094 debug("Offering agent key: %s", comment);
3c0ef626 1095 xfree(comment);
1096 ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
1097 if (ret == 0)
1098 key_free(k);
1099 }
1100 if (ret == 0)
1101 debug2("userauth_pubkey_agent: no message sent");
1102 return ret;
1103}
1104
1105int
1106userauth_pubkey(Authctxt *authctxt)
1107{
1108 static int idx = 0;
1109 int sent = 0;
1110 Key *key;
1111 char *filename;
1112
1113 if (authctxt->agent != NULL) {
1114 do {
1115 sent = userauth_pubkey_agent(authctxt);
e9a17296 1116 } while (!sent && authctxt->agent->howmany > 0);
3c0ef626 1117 }
1118 while (!sent && idx < options.num_identity_files) {
1119 key = options.identity_keys[idx];
1120 filename = options.identity_files[idx];
1121 if (key == NULL) {
6a9b3198 1122 debug("Trying private key: %s", filename);
3c0ef626 1123 key = load_identity_file(filename);
1124 if (key != NULL) {
1125 sent = sign_and_send_pubkey(authctxt, key,
1126 key_sign_cb);
1127 key_free(key);
1128 }
1129 } else if (key->type != KEY_RSA1) {
6a9b3198 1130 debug("Offering public key: %s", filename);
3c0ef626 1131 sent = send_pubkey_test(authctxt, key,
1132 identity_sign_cb, idx);
1133 }
1134 idx++;
1135 }
1136 return sent;
1137}
1138
1139/*
1140 * Send userauth request message specifying keyboard-interactive method.
1141 */
1142int
1143userauth_kbdint(Authctxt *authctxt)
1144{
1145 static int attempt = 0;
1146
1147 if (attempt++ >= options.number_of_password_prompts)
1148 return 0;
1149 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1150 if (attempt > 1 && !authctxt->info_req_seen) {
1151 debug3("userauth_kbdint: disable: no info_req_seen");
1152 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1153 return 0;
1154 }
1155
1156 debug2("userauth_kbdint");
1157 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1158 packet_put_cstring(authctxt->server_user);
1159 packet_put_cstring(authctxt->service);
1160 packet_put_cstring(authctxt->method->name);
1161 packet_put_cstring(""); /* lang */
1162 packet_put_cstring(options.kbd_interactive_devices ?
1163 options.kbd_interactive_devices : "");
1164 packet_send();
1165
1166 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1167 return 1;
1168}
1169
1170/*
1171 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1172 */
1173void
e9a17296 1174input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
3c0ef626 1175{
1176 Authctxt *authctxt = ctxt;
1177 char *name, *inst, *lang, *prompt, *response;
1178 u_int num_prompts, i;
1179 int echo = 0;
1180
1181 debug2("input_userauth_info_req");
1182
1183 if (authctxt == NULL)
1184 fatal("input_userauth_info_req: no authentication context");
1185
1186 authctxt->info_req_seen = 1;
1187
1188 name = packet_get_string(NULL);
1189 inst = packet_get_string(NULL);
1190 lang = packet_get_string(NULL);
1191 if (strlen(name) > 0)
1192 log("%s", name);
1193 if (strlen(inst) > 0)
1194 log("%s", inst);
1195 xfree(name);
1196 xfree(inst);
1197 xfree(lang);
1198
1199 num_prompts = packet_get_int();
1200 /*
1201 * Begin to build info response packet based on prompts requested.
1202 * We commit to providing the correct number of responses, so if
1203 * further on we run into a problem that prevents this, we have to
1204 * be sure and clean this up and send a correct error response.
1205 */
1206 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1207 packet_put_int(num_prompts);
1208
1209 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1210 for (i = 0; i < num_prompts; i++) {
1211 prompt = packet_get_string(NULL);
1212 echo = packet_get_char();
1213
1214 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1215
1216 packet_put_cstring(response);
1217 memset(response, 0, strlen(response));
1218 xfree(response);
1219 xfree(prompt);
1220 }
e9a17296 1221 packet_check_eom(); /* done with parsing incoming message. */
3c0ef626 1222
1223 packet_add_padding(64);
1224 packet_send();
1225}
1226
f5799ae1 1227static int
680cee3b 1228ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
f5799ae1 1229 u_char *data, u_int datalen)
1230{
1231 Buffer b;
1232 struct stat st;
1233 pid_t pid;
1234 int to[2], from[2], status, version = 2;
1235
6a9b3198 1236 debug2("ssh_keysign called");
f5799ae1 1237
1238 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1239 error("ssh_keysign: no installed: %s", strerror(errno));
1240 return -1;
1241 }
1242 if (fflush(stdout) != 0)
1243 error("ssh_keysign: fflush: %s", strerror(errno));
1244 if (pipe(to) < 0) {
1245 error("ssh_keysign: pipe: %s", strerror(errno));
1246 return -1;
1247 }
1248 if (pipe(from) < 0) {
1249 error("ssh_keysign: pipe: %s", strerror(errno));
1250 return -1;
1251 }
1252 if ((pid = fork()) < 0) {
1253 error("ssh_keysign: fork: %s", strerror(errno));
1254 return -1;
1255 }
1256 if (pid == 0) {
1257 seteuid(getuid());
1258 setuid(getuid());
1259 close(from[0]);
1260 if (dup2(from[1], STDOUT_FILENO) < 0)
1261 fatal("ssh_keysign: dup2: %s", strerror(errno));
1262 close(to[1]);
1263 if (dup2(to[0], STDIN_FILENO) < 0)
1264 fatal("ssh_keysign: dup2: %s", strerror(errno));
1265 close(from[1]);
1266 close(to[0]);
1267 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1268 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1269 strerror(errno));
1270 }
1271 close(from[1]);
1272 close(to[0]);
1273
1274 buffer_init(&b);
1275 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1276 buffer_put_string(&b, data, datalen);
41b2f314 1277 ssh_msg_send(to[1], version, &b);
f5799ae1 1278
41b2f314 1279 if (ssh_msg_recv(from[0], &b) < 0) {
f5799ae1 1280 error("ssh_keysign: no reply");
1281 buffer_clear(&b);
1282 return -1;
1283 }
1284 close(from[0]);
1285 close(to[1]);
1286
1287 while (waitpid(pid, &status, 0) < 0)
1288 if (errno != EINTR)
1289 break;
1290
1291 if (buffer_get_char(&b) != version) {
1292 error("ssh_keysign: bad version");
1293 buffer_clear(&b);
1294 return -1;
1295 }
1296 *sigp = buffer_get_string(&b, lenp);
1297 buffer_clear(&b);
1298
1299 return 0;
1300}
1301
3c0ef626 1302int
1303userauth_hostbased(Authctxt *authctxt)
1304{
1305 Key *private = NULL;
f5799ae1 1306 Sensitive *sensitive = authctxt->sensitive;
3c0ef626 1307 Buffer b;
1308 u_char *signature, *blob;
1309 char *chost, *pkalg, *p;
1310 const char *service;
1311 u_int blen, slen;
1312 int ok, i, len, found = 0;
1313
1314 /* check for a useful key */
f5799ae1 1315 for (i = 0; i < sensitive->nkeys; i++) {
1316 private = sensitive->keys[i];
3c0ef626 1317 if (private && private->type != KEY_RSA1) {
1318 found = 1;
1319 /* we take and free the key */
f5799ae1 1320 sensitive->keys[i] = NULL;
3c0ef626 1321 break;
1322 }
1323 }
1324 if (!found) {
6a9b3198 1325 debug("No more client hostkeys for hostbased authentication.");
3c0ef626 1326 return 0;
1327 }
1328 if (key_to_blob(private, &blob, &blen) == 0) {
1329 key_free(private);
1330 return 0;
1331 }
1332 /* figure out a name for the client host */
1333 p = get_local_name(packet_get_connection_in());
1334 if (p == NULL) {
1335 error("userauth_hostbased: cannot get local ipaddr/name");
1336 key_free(private);
1337 return 0;
1338 }
1339 len = strlen(p) + 2;
1340 chost = xmalloc(len);
1341 strlcpy(chost, p, len);
1342 strlcat(chost, ".", len);
1343 debug2("userauth_hostbased: chost %s", chost);
6a9b3198 1344 xfree(p);
3c0ef626 1345
1346 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1347 authctxt->service;
1348 pkalg = xstrdup(key_ssh_name(private));
1349 buffer_init(&b);
1350 /* construct data */
1351 buffer_put_string(&b, session_id2, session_id2_len);
1352 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1353 buffer_put_cstring(&b, authctxt->server_user);
1354 buffer_put_cstring(&b, service);
1355 buffer_put_cstring(&b, authctxt->method->name);
1356 buffer_put_cstring(&b, pkalg);
1357 buffer_put_string(&b, blob, blen);
1358 buffer_put_cstring(&b, chost);
1359 buffer_put_cstring(&b, authctxt->local_user);
1360#ifdef DEBUG_PK
1361 buffer_dump(&b);
1362#endif
f5799ae1 1363 if (sensitive->external_keysign)
1364 ok = ssh_keysign(private, &signature, &slen,
1365 buffer_ptr(&b), buffer_len(&b));
1366 else
1367 ok = key_sign(private, &signature, &slen,
1368 buffer_ptr(&b), buffer_len(&b));
3c0ef626 1369 key_free(private);
1370 buffer_free(&b);
1371 if (ok != 0) {
1372 error("key_sign failed");
1373 xfree(chost);
1374 xfree(pkalg);
1375 return 0;
1376 }
1377 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1378 packet_put_cstring(authctxt->server_user);
1379 packet_put_cstring(authctxt->service);
1380 packet_put_cstring(authctxt->method->name);
1381 packet_put_cstring(pkalg);
1382 packet_put_string(blob, blen);
1383 packet_put_cstring(chost);
1384 packet_put_cstring(authctxt->local_user);
1385 packet_put_string(signature, slen);
1386 memset(signature, 's', slen);
1387 xfree(signature);
1388 xfree(chost);
1389 xfree(pkalg);
1390
1391 packet_send();
1392 return 1;
1393}
1394
1395/* find auth method */
1396
1397/*
1398 * given auth method name, if configurable options permit this method fill
1399 * in auth_ident field and return true, otherwise return false.
1400 */
1401static int
1402authmethod_is_enabled(Authmethod *method)
1403{
1404 if (method == NULL)
1405 return 0;
1406 /* return false if options indicate this method is disabled */
1407 if (method->enabled == NULL || *method->enabled == 0)
1408 return 0;
1409 /* return false if batch mode is enabled but method needs interactive mode */
1410 if (method->batch_flag != NULL && *method->batch_flag != 0)
1411 return 0;
1412 return 1;
1413}
1414
1415static Authmethod *
1416authmethod_lookup(const char *name)
1417{
1418 Authmethod *method = NULL;
1419 if (name != NULL)
1420 for (method = authmethods; method->name != NULL; method++)
1421 if (strcmp(name, method->name) == 0)
1422 return method;
1423 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1424 return NULL;
1425}
1426
1427/* XXX internal state */
1428static Authmethod *current = NULL;
1429static char *supported = NULL;
1430static char *preferred = NULL;
680cee3b 1431
3c0ef626 1432/*
1433 * Given the authentication method list sent by the server, return the
1434 * next method we should try. If the server initially sends a nil list,
1435 * use a built-in default list.
1436 */
1437static Authmethod *
1438authmethod_get(char *authlist)
1439{
3c0ef626 1440 char *name = NULL;
e9a17296 1441 u_int next;
3c0ef626 1442
1443 /* Use a suitable default if we're passed a nil list. */
1444 if (authlist == NULL || strlen(authlist) == 0)
1445 authlist = options.preferred_authentications;
1446
1447 if (supported == NULL || strcmp(authlist, supported) != 0) {
1448 debug3("start over, passed a different list %s", authlist);
1449 if (supported != NULL)
1450 xfree(supported);
1451 supported = xstrdup(authlist);
1452 preferred = options.preferred_authentications;
1453 debug3("preferred %s", preferred);
1454 current = NULL;
1455 } else if (current != NULL && authmethod_is_enabled(current))
1456 return current;
1457
1458 for (;;) {
1459 if ((name = match_list(preferred, supported, &next)) == NULL) {
6a9b3198 1460 debug("No more authentication methods to try.");
3c0ef626 1461 current = NULL;
1462 return NULL;
1463 }
1464 preferred += next;
1465 debug3("authmethod_lookup %s", name);
1466 debug3("remaining preferred: %s", preferred);
1467 if ((current = authmethod_lookup(name)) != NULL &&
1468 authmethod_is_enabled(current)) {
1469 debug3("authmethod_is_enabled %s", name);
6a9b3198 1470 debug("Next authentication method: %s", name);
3c0ef626 1471 return current;
1472 }
1473 }
1474}
1475
3c0ef626 1476static char *
1477authmethods_get(void)
1478{
1479 Authmethod *method = NULL;
e9a17296 1480 Buffer b;
1481 char *list;
3c0ef626 1482
e9a17296 1483 buffer_init(&b);
3c0ef626 1484 for (method = authmethods; method->name != NULL; method++) {
1485 if (authmethod_is_enabled(method)) {
e9a17296 1486 if (buffer_len(&b) > 0)
1487 buffer_append(&b, ",", 1);
1488 buffer_append(&b, method->name, strlen(method->name));
3c0ef626 1489 }
1490 }
e9a17296 1491 buffer_append(&b, "\0", 1);
1492 list = xstrdup(buffer_ptr(&b));
1493 buffer_free(&b);
1494 return list;
3c0ef626 1495}
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