?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Import OpenSSH-6.7p1.
[dragonfly.git] / crypto / openssh / sshconnect2.c
blob68f7f4fdd2c1d73386cef644623a1b416a4101f1
1 /* $OpenBSD: sshconnect2.c,v 1.210 2014/07/15 15:54:14 millert Exp $ */
2 /*
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
4 * Copyright (c) 2008 Damien Miller. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27 #include "includes.h"
28
29 #include <sys/types.h>
30 #include <sys/socket.h>
31 #include <sys/wait.h>
32 #include <sys/stat.h>
33
34 #include <errno.h>
35 #include <fcntl.h>
36 #include <netdb.h>
37 #include <pwd.h>
38 #include <signal.h>
39 #include <stdarg.h>
40 #include <stdio.h>
41 #include <string.h>
42 #include <unistd.h>
43 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS)
44 #include <vis.h>
45 #endif
46
47 #include "openbsd-compat/sys-queue.h"
48
49 #include "xmalloc.h"
50 #include "ssh.h"
51 #include "ssh2.h"
52 #include "buffer.h"
53 #include "packet.h"
54 #include "compat.h"
55 #include "cipher.h"
56 #include "key.h"
57 #include "kex.h"
58 #include "myproposal.h"
59 #include "sshconnect.h"
60 #include "authfile.h"
61 #include "dh.h"
62 #include "authfd.h"
63 #include "log.h"
64 #include "misc.h"
65 #include "readconf.h"
66 #include "match.h"
67 #include "dispatch.h"
68 #include "canohost.h"
69 #include "msg.h"
70 #include "pathnames.h"
71 #include "uidswap.h"
72 #include "hostfile.h"
73
74 #ifdef GSSAPI
75 #include "ssh-gss.h"
76 #endif
77
78 /* import */
79 extern char *client_version_string;
80 extern char *server_version_string;
81 extern Options options;
82
83 /*
84 * SSH2 key exchange
85 */
86
87 u_char *session_id2 = NULL;
88 u_int session_id2_len = 0;
89
90 char *xxx_host;
91 struct sockaddr *xxx_hostaddr;
92
93 Kex *xxx_kex = NULL;
94
95 static int
96 verify_host_key_callback(Key *hostkey)
97 {
98 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
99 fatal("Host key verification failed.");
100 return 0;
101 }
102
103 static char *
104 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port)
105 {
106 char *oavail, *avail, *first, *last, *alg, *hostname, *ret;
107 size_t maxlen;
108 struct hostkeys *hostkeys;
109 int ktype;
110 u_int i;
111
112 /* Find all hostkeys for this hostname */
113 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL);
114 hostkeys = init_hostkeys();
115 for (i = 0; i < options.num_user_hostfiles; i++)
116 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]);
117 for (i = 0; i < options.num_system_hostfiles; i++)
118 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]);
119
120 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG);
121 maxlen = strlen(avail) + 1;
122 first = xmalloc(maxlen);
123 last = xmalloc(maxlen);
124 *first = *last = '\0';
125
126 #define ALG_APPEND(to, from) \
127 do { \
128 if (*to != '\0') \
129 strlcat(to, ",", maxlen); \
130 strlcat(to, from, maxlen); \
131 } while (0)
132
133 while ((alg = strsep(&avail, ",")) && *alg != '\0') {
134 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC)
135 fatal("%s: unknown alg %s", __func__, alg);
136 if (lookup_key_in_hostkeys_by_type(hostkeys,
137 key_type_plain(ktype), NULL))
138 ALG_APPEND(first, alg);
139 else
140 ALG_APPEND(last, alg);
141 }
142 #undef ALG_APPEND
143 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last);
144 if (*first != '\0')
145 debug3("%s: prefer hostkeyalgs: %s", __func__, first);
146
147 free(first);
148 free(last);
149 free(hostname);
150 free(oavail);
151 free_hostkeys(hostkeys);
152
153 return ret;
154 }
155
156 void
157 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
158 {
159 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
160 Kex *kex;
161
162 xxx_host = host;
163 xxx_hostaddr = hostaddr;
164
165 if (options.ciphers == (char *)-1) {
166 logit("No valid ciphers for protocol version 2 given, using defaults.");
167 options.ciphers = NULL;
168 }
169 if (options.ciphers != NULL) {
170 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
171 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
172 }
173 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
174 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
175 myproposal[PROPOSAL_ENC_ALGS_STOC] =
176 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
177 if (options.compression) {
178 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
179 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
180 } else {
181 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
182 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
183 }
184 if (options.macs != NULL) {
185 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
186 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
187 }
188 if (options.hostkeyalgorithms != NULL)
189 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
190 compat_pkalg_proposal(options.hostkeyalgorithms);
191 else {
192 /* Prefer algorithms that we already have keys for */
193 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
194 compat_pkalg_proposal(
195 order_hostkeyalgs(host, hostaddr, port));
196 }
197 if (options.kex_algorithms != NULL)
198 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
199 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(
200 myproposal[PROPOSAL_KEX_ALGS]);
201
202 if (options.rekey_limit || options.rekey_interval)
203 packet_set_rekey_limits((u_int32_t)options.rekey_limit,
204 (time_t)options.rekey_interval);
205
206 /* start key exchange */
207 kex = kex_setup(myproposal);
208 #ifdef WITH_OPENSSL
209 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
210 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
211 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
212 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
213 kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
214 #endif
215 kex->kex[KEX_C25519_SHA256] = kexc25519_client;
216 kex->client_version_string=client_version_string;
217 kex->server_version_string=server_version_string;
218 kex->verify_host_key=&verify_host_key_callback;
219
220 xxx_kex = kex;
221
222 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
223
224 if (options.use_roaming && !kex->roaming) {
225 debug("Roaming not allowed by server");
226 options.use_roaming = 0;
227 }
228
229 session_id2 = kex->session_id;
230 session_id2_len = kex->session_id_len;
231
232 #ifdef DEBUG_KEXDH
233 /* send 1st encrypted/maced/compressed message */
234 packet_start(SSH2_MSG_IGNORE);
235 packet_put_cstring("markus");
236 packet_send();
237 packet_write_wait();
238 #endif
239 }
240
241 /*
242 * Authenticate user
243 */
244
245 typedef struct Authctxt Authctxt;
246 typedef struct Authmethod Authmethod;
247 typedef struct identity Identity;
248 typedef struct idlist Idlist;
249
250 struct identity {
251 TAILQ_ENTRY(identity) next;
252 AuthenticationConnection *ac; /* set if agent supports key */
253 Key *key; /* public/private key */
254 char *filename; /* comment for agent-only keys */
255 int tried;
256 int isprivate; /* key points to the private key */
257 int userprovided;
258 };
259 TAILQ_HEAD(idlist, identity);
260
261 struct Authctxt {
262 const char *server_user;
263 const char *local_user;
264 const char *host;
265 const char *service;
266 Authmethod *method;
267 sig_atomic_t success;
268 char *authlist;
269 /* pubkey */
270 Idlist keys;
271 AuthenticationConnection *agent;
272 /* hostbased */
273 Sensitive *sensitive;
274 /* kbd-interactive */
275 int info_req_seen;
276 /* generic */
277 void *methoddata;
278 };
279 struct Authmethod {
280 char *name; /* string to compare against server's list */
281 int (*userauth)(Authctxt *authctxt);
282 void (*cleanup)(Authctxt *authctxt);
283 int *enabled; /* flag in option struct that enables method */
284 int *batch_flag; /* flag in option struct that disables method */
285 };
286
287 void input_userauth_success(int, u_int32_t, void *);
288 void input_userauth_success_unexpected(int, u_int32_t, void *);
289 void input_userauth_failure(int, u_int32_t, void *);
290 void input_userauth_banner(int, u_int32_t, void *);
291 void input_userauth_error(int, u_int32_t, void *);
292 void input_userauth_info_req(int, u_int32_t, void *);
293 void input_userauth_pk_ok(int, u_int32_t, void *);
294 void input_userauth_passwd_changereq(int, u_int32_t, void *);
295
296 int userauth_none(Authctxt *);
297 int userauth_pubkey(Authctxt *);
298 int userauth_passwd(Authctxt *);
299 int userauth_kbdint(Authctxt *);
300 int userauth_hostbased(Authctxt *);
301
302 #ifdef GSSAPI
303 int userauth_gssapi(Authctxt *authctxt);
304 void input_gssapi_response(int type, u_int32_t, void *);
305 void input_gssapi_token(int type, u_int32_t, void *);
306 void input_gssapi_hash(int type, u_int32_t, void *);
307 void input_gssapi_error(int, u_int32_t, void *);
308 void input_gssapi_errtok(int, u_int32_t, void *);
309 #endif
310
311 void userauth(Authctxt *, char *);
312
313 static int sign_and_send_pubkey(Authctxt *, Identity *);
314 static void pubkey_prepare(Authctxt *);
315 static void pubkey_cleanup(Authctxt *);
316 static Key *load_identity_file(char *, int);
317
318 static Authmethod *authmethod_get(char *authlist);
319 static Authmethod *authmethod_lookup(const char *name);
320 static char *authmethods_get(void);
321
322 Authmethod authmethods[] = {
323 #ifdef GSSAPI
324 {"gssapi-with-mic",
325 userauth_gssapi,
326 NULL,
327 &options.gss_authentication,
328 NULL},
329 #endif
330 {"hostbased",
331 userauth_hostbased,
332 NULL,
333 &options.hostbased_authentication,
334 NULL},
335 {"publickey",
336 userauth_pubkey,
337 NULL,
338 &options.pubkey_authentication,
339 NULL},
340 {"keyboard-interactive",
341 userauth_kbdint,
342 NULL,
343 &options.kbd_interactive_authentication,
344 &options.batch_mode},
345 {"password",
346 userauth_passwd,
347 NULL,
348 &options.password_authentication,
349 &options.batch_mode},
350 {"none",
351 userauth_none,
352 NULL,
353 NULL,
354 NULL},
355 {NULL, NULL, NULL, NULL, NULL}
356 };
357
358 void
359 ssh_userauth2(const char *local_user, const char *server_user, char *host,
360 Sensitive *sensitive)
361 {
362 Authctxt authctxt;
363 int type;
364
365 if (options.challenge_response_authentication)
366 options.kbd_interactive_authentication = 1;
367
368 packet_start(SSH2_MSG_SERVICE_REQUEST);
369 packet_put_cstring("ssh-userauth");
370 packet_send();
371 debug("SSH2_MSG_SERVICE_REQUEST sent");
372 packet_write_wait();
373 type = packet_read();
374 if (type != SSH2_MSG_SERVICE_ACCEPT)
375 fatal("Server denied authentication request: %d", type);
376 if (packet_remaining() > 0) {
377 char *reply = packet_get_string(NULL);
378 debug2("service_accept: %s", reply);
379 free(reply);
380 } else {
381 debug2("buggy server: service_accept w/o service");
382 }
383 packet_check_eom();
384 debug("SSH2_MSG_SERVICE_ACCEPT received");
385
386 if (options.preferred_authentications == NULL)
387 options.preferred_authentications = authmethods_get();
388
389 /* setup authentication context */
390 memset(&authctxt, 0, sizeof(authctxt));
391 pubkey_prepare(&authctxt);
392 authctxt.server_user = server_user;
393 authctxt.local_user = local_user;
394 authctxt.host = host;
395 authctxt.service = "ssh-connection"; /* service name */
396 authctxt.success = 0;
397 authctxt.method = authmethod_lookup("none");
398 authctxt.authlist = NULL;
399 authctxt.methoddata = NULL;
400 authctxt.sensitive = sensitive;
401 authctxt.info_req_seen = 0;
402 if (authctxt.method == NULL)
403 fatal("ssh_userauth2: internal error: cannot send userauth none request");
404
405 /* initial userauth request */
406 userauth_none(&authctxt);
407
408 dispatch_init(&input_userauth_error);
409 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
410 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
411 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
412 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
413
414 pubkey_cleanup(&authctxt);
415 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
416
417 debug("Authentication succeeded (%s).", authctxt.method->name);
418 }
419
420 void
421 userauth(Authctxt *authctxt, char *authlist)
422 {
423 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
424 authctxt->method->cleanup(authctxt);
425
426 free(authctxt->methoddata);
427 authctxt->methoddata = NULL;
428 if (authlist == NULL) {
429 authlist = authctxt->authlist;
430 } else {
431 free(authctxt->authlist);
432 authctxt->authlist = authlist;
433 }
434 for (;;) {
435 Authmethod *method = authmethod_get(authlist);
436 if (method == NULL)
437 fatal("Permission denied (%s).", authlist);
438 authctxt->method = method;
439
440 /* reset the per method handler */
441 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
442 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
443
444 /* and try new method */
445 if (method->userauth(authctxt) != 0) {
446 debug2("we sent a %s packet, wait for reply", method->name);
447 break;
448 } else {
449 debug2("we did not send a packet, disable method");
450 method->enabled = NULL;
451 }
452 }
453 }
454
455 /* ARGSUSED */
456 void
457 input_userauth_error(int type, u_int32_t seq, void *ctxt)
458 {
459 fatal("input_userauth_error: bad message during authentication: "
460 "type %d", type);
461 }
462
463 /* ARGSUSED */
464 void
465 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
466 {
467 char *msg, *raw, *lang;
468 u_int len;
469
470 debug3("input_userauth_banner");
471 raw = packet_get_string(&len);
472 lang = packet_get_string(NULL);
473 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
474 if (len > 65536)
475 len = 65536;
476 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
477 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH);
478 fprintf(stderr, "%s", msg);
479 free(msg);
480 }
481 free(raw);
482 free(lang);
483 }
484
485 /* ARGSUSED */
486 void
487 input_userauth_success(int type, u_int32_t seq, void *ctxt)
488 {
489 Authctxt *authctxt = ctxt;
490
491 if (authctxt == NULL)
492 fatal("input_userauth_success: no authentication context");
493 free(authctxt->authlist);
494 authctxt->authlist = NULL;
495 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
496 authctxt->method->cleanup(authctxt);
497 free(authctxt->methoddata);
498 authctxt->methoddata = NULL;
499 authctxt->success = 1; /* break out */
500 }
501
502 void
503 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt)
504 {
505 Authctxt *authctxt = ctxt;
506
507 if (authctxt == NULL)
508 fatal("%s: no authentication context", __func__);
509
510 fatal("Unexpected authentication success during %s.",
511 authctxt->method->name);
512 }
513
514 /* ARGSUSED */
515 void
516 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
517 {
518 Authctxt *authctxt = ctxt;
519 char *authlist = NULL;
520 int partial;
521
522 if (authctxt == NULL)
523 fatal("input_userauth_failure: no authentication context");
524
525 authlist = packet_get_string(NULL);
526 partial = packet_get_char();
527 packet_check_eom();
528
529 if (partial != 0) {
530 logit("Authenticated with partial success.");
531 /* reset state */
532 pubkey_cleanup(authctxt);
533 pubkey_prepare(authctxt);
534 }
535 debug("Authentications that can continue: %s", authlist);
536
537 userauth(authctxt, authlist);
538 }
539
540 /* ARGSUSED */
541 void
542 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
543 {
544 Authctxt *authctxt = ctxt;
545 Key *key = NULL;
546 Identity *id = NULL;
547 Buffer b;
548 int pktype, sent = 0;
549 u_int alen, blen;
550 char *pkalg, *fp;
551 u_char *pkblob;
552
553 if (authctxt == NULL)
554 fatal("input_userauth_pk_ok: no authentication context");
555 if (datafellows & SSH_BUG_PKOK) {
556 /* this is similar to SSH_BUG_PKAUTH */
557 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
558 pkblob = packet_get_string(&blen);
559 buffer_init(&b);
560 buffer_append(&b, pkblob, blen);
561 pkalg = buffer_get_string(&b, &alen);
562 buffer_free(&b);
563 } else {
564 pkalg = packet_get_string(&alen);
565 pkblob = packet_get_string(&blen);
566 }
567 packet_check_eom();
568
569 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
570
571 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
572 debug("unknown pkalg %s", pkalg);
573 goto done;
574 }
575 if ((key = key_from_blob(pkblob, blen)) == NULL) {
576 debug("no key from blob. pkalg %s", pkalg);
577 goto done;
578 }
579 if (key->type != pktype) {
580 error("input_userauth_pk_ok: type mismatch "
581 "for decoded key (received %d, expected %d)",
582 key->type, pktype);
583 goto done;
584 }
585 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
586 debug2("input_userauth_pk_ok: fp %s", fp);
587 free(fp);
588
589 /*
590 * search keys in the reverse order, because last candidate has been
591 * moved to the end of the queue. this also avoids confusion by
592 * duplicate keys
593 */
594 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
595 if (key_equal(key, id->key)) {
596 sent = sign_and_send_pubkey(authctxt, id);
597 break;
598 }
599 }
600 done:
601 if (key != NULL)
602 key_free(key);
603 free(pkalg);
604 free(pkblob);
605
606 /* try another method if we did not send a packet */
607 if (sent == 0)
608 userauth(authctxt, NULL);
609 }
610
611 #ifdef GSSAPI
612 int
613 userauth_gssapi(Authctxt *authctxt)
614 {
615 Gssctxt *gssctxt = NULL;
616 static gss_OID_set gss_supported = NULL;
617 static u_int mech = 0;
618 OM_uint32 min;
619 int ok = 0;
620
621 /* Try one GSSAPI method at a time, rather than sending them all at
622 * once. */
623
624 if (gss_supported == NULL)
625 gss_indicate_mechs(&min, &gss_supported);
626
627 /* Check to see if the mechanism is usable before we offer it */
628 while (mech < gss_supported->count && !ok) {
629 /* My DER encoding requires length<128 */
630 if (gss_supported->elements[mech].length < 128 &&
631 ssh_gssapi_check_mechanism(&gssctxt,
632 &gss_supported->elements[mech], authctxt->host)) {
633 ok = 1; /* Mechanism works */
634 } else {
635 mech++;
636 }
637 }
638
639 if (!ok)
640 return 0;
641
642 authctxt->methoddata=(void *)gssctxt;
643
644 packet_start(SSH2_MSG_USERAUTH_REQUEST);
645 packet_put_cstring(authctxt->server_user);
646 packet_put_cstring(authctxt->service);
647 packet_put_cstring(authctxt->method->name);
648
649 packet_put_int(1);
650
651 packet_put_int((gss_supported->elements[mech].length) + 2);
652 packet_put_char(SSH_GSS_OIDTYPE);
653 packet_put_char(gss_supported->elements[mech].length);
654 packet_put_raw(gss_supported->elements[mech].elements,
655 gss_supported->elements[mech].length);
656
657 packet_send();
658
659 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
660 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
661 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
662 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
663
664 mech++; /* Move along to next candidate */
665
666 return 1;
667 }
668
669 static OM_uint32
670 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
671 {
672 Authctxt *authctxt = ctxt;
673 Gssctxt *gssctxt = authctxt->methoddata;
674 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
675 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
676 gss_buffer_desc gssbuf;
677 OM_uint32 status, ms, flags;
678 Buffer b;
679
680 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
681 recv_tok, &send_tok, &flags);
682
683 if (send_tok.length > 0) {
684 if (GSS_ERROR(status))
685 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
686 else
687 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
688
689 packet_put_string(send_tok.value, send_tok.length);
690 packet_send();
691 gss_release_buffer(&ms, &send_tok);
692 }
693
694 if (status == GSS_S_COMPLETE) {
695 /* send either complete or MIC, depending on mechanism */
696 if (!(flags & GSS_C_INTEG_FLAG)) {
697 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
698 packet_send();
699 } else {
700 ssh_gssapi_buildmic(&b, authctxt->server_user,
701 authctxt->service, "gssapi-with-mic");
702
703 gssbuf.value = buffer_ptr(&b);
704 gssbuf.length = buffer_len(&b);
705
706 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
707
708 if (!GSS_ERROR(status)) {
709 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
710 packet_put_string(mic.value, mic.length);
711
712 packet_send();
713 }
714
715 buffer_free(&b);
716 gss_release_buffer(&ms, &mic);
717 }
718 }
719
720 return status;
721 }
722
723 /* ARGSUSED */
724 void
725 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
726 {
727 Authctxt *authctxt = ctxt;
728 Gssctxt *gssctxt;
729 int oidlen;
730 char *oidv;
731
732 if (authctxt == NULL)
733 fatal("input_gssapi_response: no authentication context");
734 gssctxt = authctxt->methoddata;
735
736 /* Setup our OID */
737 oidv = packet_get_string(&oidlen);
738
739 if (oidlen <= 2 ||
740 oidv[0] != SSH_GSS_OIDTYPE ||
741 oidv[1] != oidlen - 2) {
742 free(oidv);
743 debug("Badly encoded mechanism OID received");
744 userauth(authctxt, NULL);
745 return;
746 }
747
748 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
749 fatal("Server returned different OID than expected");
750
751 packet_check_eom();
752
753 free(oidv);
754
755 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
756 /* Start again with next method on list */
757 debug("Trying to start again");
758 userauth(authctxt, NULL);
759 return;
760 }
761 }
762
763 /* ARGSUSED */
764 void
765 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
766 {
767 Authctxt *authctxt = ctxt;
768 gss_buffer_desc recv_tok;
769 OM_uint32 status;
770 u_int slen;
771
772 if (authctxt == NULL)
773 fatal("input_gssapi_response: no authentication context");
774
775 recv_tok.value = packet_get_string(&slen);
776 recv_tok.length = slen; /* safe typecast */
777
778 packet_check_eom();
779
780 status = process_gssapi_token(ctxt, &recv_tok);
781
782 free(recv_tok.value);
783
784 if (GSS_ERROR(status)) {
785 /* Start again with the next method in the list */
786 userauth(authctxt, NULL);
787 return;
788 }
789 }
790
791 /* ARGSUSED */
792 void
793 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
794 {
795 Authctxt *authctxt = ctxt;
796 Gssctxt *gssctxt;
797 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
798 gss_buffer_desc recv_tok;
799 OM_uint32 ms;
800 u_int len;
801
802 if (authctxt == NULL)
803 fatal("input_gssapi_response: no authentication context");
804 gssctxt = authctxt->methoddata;
805
806 recv_tok.value = packet_get_string(&len);
807 recv_tok.length = len;
808
809 packet_check_eom();
810
811 /* Stick it into GSSAPI and see what it says */
812 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
813 &recv_tok, &send_tok, NULL);
814
815 free(recv_tok.value);
816 gss_release_buffer(&ms, &send_tok);
817
818 /* Server will be returning a failed packet after this one */
819 }
820
821 /* ARGSUSED */
822 void
823 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
824 {
825 char *msg;
826 char *lang;
827
828 /* maj */(void)packet_get_int();
829 /* min */(void)packet_get_int();
830 msg=packet_get_string(NULL);
831 lang=packet_get_string(NULL);
832
833 packet_check_eom();
834
835 debug("Server GSSAPI Error:\n%s", msg);
836 free(msg);
837 free(lang);
838 }
839 #endif /* GSSAPI */
840
841 int
842 userauth_none(Authctxt *authctxt)
843 {
844 /* initial userauth request */
845 packet_start(SSH2_MSG_USERAUTH_REQUEST);
846 packet_put_cstring(authctxt->server_user);
847 packet_put_cstring(authctxt->service);
848 packet_put_cstring(authctxt->method->name);
849 packet_send();
850 return 1;
851 }
852
853 int
854 userauth_passwd(Authctxt *authctxt)
855 {
856 static int attempt = 0;
857 char prompt[150];
858 char *password;
859 const char *host = options.host_key_alias ? options.host_key_alias :
860 authctxt->host;
861
862 if (attempt++ >= options.number_of_password_prompts)
863 return 0;
864
865 if (attempt != 1)
866 error("Permission denied, please try again.");
867
868 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
869 authctxt->server_user, host);
870 password = read_passphrase(prompt, 0);
871 packet_start(SSH2_MSG_USERAUTH_REQUEST);
872 packet_put_cstring(authctxt->server_user);
873 packet_put_cstring(authctxt->service);
874 packet_put_cstring(authctxt->method->name);
875 packet_put_char(0);
876 packet_put_cstring(password);
877 explicit_bzero(password, strlen(password));
878 free(password);
879 packet_add_padding(64);
880 packet_send();
881
882 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
883 &input_userauth_passwd_changereq);
884
885 return 1;
886 }
887
888 /*
889 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
890 */
891 /* ARGSUSED */
892 void
893 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
894 {
895 Authctxt *authctxt = ctxt;
896 char *info, *lang, *password = NULL, *retype = NULL;
897 char prompt[150];
898 const char *host = options.host_key_alias ? options.host_key_alias :
899 authctxt->host;
900
901 debug2("input_userauth_passwd_changereq");
902
903 if (authctxt == NULL)
904 fatal("input_userauth_passwd_changereq: "
905 "no authentication context");
906
907 info = packet_get_string(NULL);
908 lang = packet_get_string(NULL);
909 if (strlen(info) > 0)
910 logit("%s", info);
911 free(info);
912 free(lang);
913 packet_start(SSH2_MSG_USERAUTH_REQUEST);
914 packet_put_cstring(authctxt->server_user);
915 packet_put_cstring(authctxt->service);
916 packet_put_cstring(authctxt->method->name);
917 packet_put_char(1); /* additional info */
918 snprintf(prompt, sizeof(prompt),
919 "Enter %.30s@%.128s's old password: ",
920 authctxt->server_user, host);
921 password = read_passphrase(prompt, 0);
922 packet_put_cstring(password);
923 explicit_bzero(password, strlen(password));
924 free(password);
925 password = NULL;
926 while (password == NULL) {
927 snprintf(prompt, sizeof(prompt),
928 "Enter %.30s@%.128s's new password: ",
929 authctxt->server_user, host);
930 password = read_passphrase(prompt, RP_ALLOW_EOF);
931 if (password == NULL) {
932 /* bail out */
933 return;
934 }
935 snprintf(prompt, sizeof(prompt),
936 "Retype %.30s@%.128s's new password: ",
937 authctxt->server_user, host);
938 retype = read_passphrase(prompt, 0);
939 if (strcmp(password, retype) != 0) {
940 explicit_bzero(password, strlen(password));
941 free(password);
942 logit("Mismatch; try again, EOF to quit.");
943 password = NULL;
944 }
945 explicit_bzero(retype, strlen(retype));
946 free(retype);
947 }
948 packet_put_cstring(password);
949 explicit_bzero(password, strlen(password));
950 free(password);
951 packet_add_padding(64);
952 packet_send();
953
954 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
955 &input_userauth_passwd_changereq);
956 }
957
958 static int
959 identity_sign(Identity *id, u_char **sigp, u_int *lenp,
960 u_char *data, u_int datalen)
961 {
962 Key *prv;
963 int ret;
964
965 /* the agent supports this key */
966 if (id->ac)
967 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
968 data, datalen));
969 /*
970 * we have already loaded the private key or
971 * the private key is stored in external hardware
972 */
973 if (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))
974 return (key_sign(id->key, sigp, lenp, data, datalen));
975 /* load the private key from the file */
976 if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL)
977 return (-1);
978 ret = key_sign(prv, sigp, lenp, data, datalen);
979 key_free(prv);
980 return (ret);
981 }
982
983 static int
984 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
985 {
986 Buffer b;
987 u_char *blob, *signature;
988 u_int bloblen, slen;
989 u_int skip = 0;
990 int ret = -1;
991 int have_sig = 1;
992 char *fp;
993
994 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
995 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp);
996 free(fp);
997
998 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
999 /* we cannot handle this key */
1000 debug3("sign_and_send_pubkey: cannot handle key");
1001 return 0;
1002 }
1003 /* data to be signed */
1004 buffer_init(&b);
1005 if (datafellows & SSH_OLD_SESSIONID) {
1006 buffer_append(&b, session_id2, session_id2_len);
1007 skip = session_id2_len;
1008 } else {
1009 buffer_put_string(&b, session_id2, session_id2_len);
1010 skip = buffer_len(&b);
1011 }
1012 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1013 buffer_put_cstring(&b, authctxt->server_user);
1014 buffer_put_cstring(&b,
1015 datafellows & SSH_BUG_PKSERVICE ?
1016 "ssh-userauth" :
1017 authctxt->service);
1018 if (datafellows & SSH_BUG_PKAUTH) {
1019 buffer_put_char(&b, have_sig);
1020 } else {
1021 buffer_put_cstring(&b, authctxt->method->name);
1022 buffer_put_char(&b, have_sig);
1023 buffer_put_cstring(&b, key_ssh_name(id->key));
1024 }
1025 buffer_put_string(&b, blob, bloblen);
1026
1027 /* generate signature */
1028 ret = identity_sign(id, &signature, &slen,
1029 buffer_ptr(&b), buffer_len(&b));
1030 if (ret == -1) {
1031 free(blob);
1032 buffer_free(&b);
1033 return 0;
1034 }
1035 #ifdef DEBUG_PK
1036 buffer_dump(&b);
1037 #endif
1038 if (datafellows & SSH_BUG_PKSERVICE) {
1039 buffer_clear(&b);
1040 buffer_append(&b, session_id2, session_id2_len);
1041 skip = session_id2_len;
1042 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1043 buffer_put_cstring(&b, authctxt->server_user);
1044 buffer_put_cstring(&b, authctxt->service);
1045 buffer_put_cstring(&b, authctxt->method->name);
1046 buffer_put_char(&b, have_sig);
1047 if (!(datafellows & SSH_BUG_PKAUTH))
1048 buffer_put_cstring(&b, key_ssh_name(id->key));
1049 buffer_put_string(&b, blob, bloblen);
1050 }
1051 free(blob);
1052
1053 /* append signature */
1054 buffer_put_string(&b, signature, slen);
1055 free(signature);
1056
1057 /* skip session id and packet type */
1058 if (buffer_len(&b) < skip + 1)
1059 fatal("userauth_pubkey: internal error");
1060 buffer_consume(&b, skip + 1);
1061
1062 /* put remaining data from buffer into packet */
1063 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1064 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1065 buffer_free(&b);
1066 packet_send();
1067
1068 return 1;
1069 }
1070
1071 static int
1072 send_pubkey_test(Authctxt *authctxt, Identity *id)
1073 {
1074 u_char *blob;
1075 u_int bloblen, have_sig = 0;
1076
1077 debug3("send_pubkey_test");
1078
1079 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1080 /* we cannot handle this key */
1081 debug3("send_pubkey_test: cannot handle key");
1082 return 0;
1083 }
1084 /* register callback for USERAUTH_PK_OK message */
1085 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1086
1087 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1088 packet_put_cstring(authctxt->server_user);
1089 packet_put_cstring(authctxt->service);
1090 packet_put_cstring(authctxt->method->name);
1091 packet_put_char(have_sig);
1092 if (!(datafellows & SSH_BUG_PKAUTH))
1093 packet_put_cstring(key_ssh_name(id->key));
1094 packet_put_string(blob, bloblen);
1095 free(blob);
1096 packet_send();
1097 return 1;
1098 }
1099
1100 static Key *
1101 load_identity_file(char *filename, int userprovided)
1102 {
1103 Key *private;
1104 char prompt[300], *passphrase;
1105 int perm_ok = 0, quit, i;
1106 struct stat st;
1107
1108 if (stat(filename, &st) < 0) {
1109 (userprovided ? logit : debug3)("no such identity: %s: %s",
1110 filename, strerror(errno));
1111 return NULL;
1112 }
1113 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1114 if (!perm_ok) {
1115 if (private != NULL)
1116 key_free(private);
1117 return NULL;
1118 }
1119 if (private == NULL) {
1120 if (options.batch_mode)
1121 return NULL;
1122 snprintf(prompt, sizeof prompt,
1123 "Enter passphrase for key '%.100s': ", filename);
1124 for (i = 0; i < options.number_of_password_prompts; i++) {
1125 passphrase = read_passphrase(prompt, 0);
1126 if (strcmp(passphrase, "") != 0) {
1127 private = key_load_private_type(KEY_UNSPEC,
1128 filename, passphrase, NULL, NULL);
1129 quit = 0;
1130 } else {
1131 debug2("no passphrase given, try next key");
1132 quit = 1;
1133 }
1134 explicit_bzero(passphrase, strlen(passphrase));
1135 free(passphrase);
1136 if (private != NULL || quit)
1137 break;
1138 debug2("bad passphrase given, try again...");
1139 }
1140 }
1141 return private;
1142 }
1143
1144 /*
1145 * try keys in the following order:
1146 * 1. agent keys that are found in the config file
1147 * 2. other agent keys
1148 * 3. keys that are only listed in the config file
1149 */
1150 static void
1151 pubkey_prepare(Authctxt *authctxt)
1152 {
1153 Identity *id, *id2, *tmp;
1154 Idlist agent, files, *preferred;
1155 Key *key;
1156 AuthenticationConnection *ac;
1157 char *comment;
1158 int i, found;
1159
1160 TAILQ_INIT(&agent); /* keys from the agent */
1161 TAILQ_INIT(&files); /* keys from the config file */
1162 preferred = &authctxt->keys;
1163 TAILQ_INIT(preferred); /* preferred order of keys */
1164
1165 /* list of keys stored in the filesystem and PKCS#11 */
1166 for (i = 0; i < options.num_identity_files; i++) {
1167 key = options.identity_keys[i];
1168 if (key && key->type == KEY_RSA1)
1169 continue;
1170 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER)
1171 continue;
1172 options.identity_keys[i] = NULL;
1173 id = xcalloc(1, sizeof(*id));
1174 id->key = key;
1175 id->filename = xstrdup(options.identity_files[i]);
1176 id->userprovided = options.identity_file_userprovided[i];
1177 TAILQ_INSERT_TAIL(&files, id, next);
1178 }
1179 /* Prefer PKCS11 keys that are explicitly listed */
1180 TAILQ_FOREACH_SAFE(id, &files, next, tmp) {
1181 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0)
1182 continue;
1183 found = 0;
1184 TAILQ_FOREACH(id2, &files, next) {
1185 if (id2->key == NULL ||
1186 (id2->key->flags & SSHKEY_FLAG_EXT) == 0)
1187 continue;
1188 if (key_equal(id->key, id2->key)) {
1189 TAILQ_REMOVE(&files, id, next);
1190 TAILQ_INSERT_TAIL(preferred, id, next);
1191 found = 1;
1192 break;
1193 }
1194 }
1195 /* If IdentitiesOnly set and key not found then don't use it */
1196 if (!found && options.identities_only) {
1197 TAILQ_REMOVE(&files, id, next);
1198 explicit_bzero(id, sizeof(*id));
1199 free(id);
1200 }
1201 }
1202 /* list of keys supported by the agent */
1203 if ((ac = ssh_get_authentication_connection())) {
1204 for (key = ssh_get_first_identity(ac, &comment, 2);
1205 key != NULL;
1206 key = ssh_get_next_identity(ac, &comment, 2)) {
1207 found = 0;
1208 TAILQ_FOREACH(id, &files, next) {
1209 /* agent keys from the config file are preferred */
1210 if (key_equal(key, id->key)) {
1211 key_free(key);
1212 free(comment);
1213 TAILQ_REMOVE(&files, id, next);
1214 TAILQ_INSERT_TAIL(preferred, id, next);
1215 id->ac = ac;
1216 found = 1;
1217 break;
1218 }
1219 }
1220 if (!found && !options.identities_only) {
1221 id = xcalloc(1, sizeof(*id));
1222 id->key = key;
1223 id->filename = comment;
1224 id->ac = ac;
1225 TAILQ_INSERT_TAIL(&agent, id, next);
1226 }
1227 }
1228 /* append remaining agent keys */
1229 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1230 TAILQ_REMOVE(&agent, id, next);
1231 TAILQ_INSERT_TAIL(preferred, id, next);
1232 }
1233 authctxt->agent = ac;
1234 }
1235 /* append remaining keys from the config file */
1236 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1237 TAILQ_REMOVE(&files, id, next);
1238 TAILQ_INSERT_TAIL(preferred, id, next);
1239 }
1240 TAILQ_FOREACH(id, preferred, next) {
1241 debug2("key: %s (%p),%s", id->filename, id->key,
1242 id->userprovided ? " explicit" : "");
1243 }
1244 }
1245
1246 static void
1247 pubkey_cleanup(Authctxt *authctxt)
1248 {
1249 Identity *id;
1250
1251 if (authctxt->agent != NULL)
1252 ssh_close_authentication_connection(authctxt->agent);
1253 for (id = TAILQ_FIRST(&authctxt->keys); id;
1254 id = TAILQ_FIRST(&authctxt->keys)) {
1255 TAILQ_REMOVE(&authctxt->keys, id, next);
1256 if (id->key)
1257 key_free(id->key);
1258 free(id->filename);
1259 free(id);
1260 }
1261 }
1262
1263 int
1264 userauth_pubkey(Authctxt *authctxt)
1265 {
1266 Identity *id;
1267 int sent = 0;
1268
1269 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1270 if (id->tried++)
1271 return (0);
1272 /* move key to the end of the queue */
1273 TAILQ_REMOVE(&authctxt->keys, id, next);
1274 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1275 /*
1276 * send a test message if we have the public key. for
1277 * encrypted keys we cannot do this and have to load the
1278 * private key instead
1279 */
1280 if (id->key != NULL) {
1281 if (key_type_plain(id->key->type) == KEY_RSA &&
1282 (datafellows & SSH_BUG_RSASIGMD5) != 0) {
1283 debug("Skipped %s key %s for RSA/MD5 server",
1284 key_type(id->key), id->filename);
1285 } else if (id->key->type != KEY_RSA1) {
1286 debug("Offering %s public key: %s",
1287 key_type(id->key), id->filename);
1288 sent = send_pubkey_test(authctxt, id);
1289 }
1290 } else {
1291 debug("Trying private key: %s", id->filename);
1292 id->key = load_identity_file(id->filename,
1293 id->userprovided);
1294 if (id->key != NULL) {
1295 id->isprivate = 1;
1296 if (key_type_plain(id->key->type) == KEY_RSA &&
1297 (datafellows & SSH_BUG_RSASIGMD5) != 0) {
1298 debug("Skipped %s key %s for RSA/MD5 "
1299 "server", key_type(id->key),
1300 id->filename);
1301 } else {
1302 sent = sign_and_send_pubkey(
1303 authctxt, id);
1304 }
1305 key_free(id->key);
1306 id->key = NULL;
1307 }
1308 }
1309 if (sent)
1310 return (sent);
1311 }
1312 return (0);
1313 }
1314
1315 /*
1316 * Send userauth request message specifying keyboard-interactive method.
1317 */
1318 int
1319 userauth_kbdint(Authctxt *authctxt)
1320 {
1321 static int attempt = 0;
1322
1323 if (attempt++ >= options.number_of_password_prompts)
1324 return 0;
1325 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1326 if (attempt > 1 && !authctxt->info_req_seen) {
1327 debug3("userauth_kbdint: disable: no info_req_seen");
1328 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1329 return 0;
1330 }
1331
1332 debug2("userauth_kbdint");
1333 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1334 packet_put_cstring(authctxt->server_user);
1335 packet_put_cstring(authctxt->service);
1336 packet_put_cstring(authctxt->method->name);
1337 packet_put_cstring(""); /* lang */
1338 packet_put_cstring(options.kbd_interactive_devices ?
1339 options.kbd_interactive_devices : "");
1340 packet_send();
1341
1342 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1343 return 1;
1344 }
1345
1346 /*
1347 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1348 */
1349 void
1350 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1351 {
1352 Authctxt *authctxt = ctxt;
1353 char *name, *inst, *lang, *prompt, *response;
1354 u_int num_prompts, i;
1355 int echo = 0;
1356
1357 debug2("input_userauth_info_req");
1358
1359 if (authctxt == NULL)
1360 fatal("input_userauth_info_req: no authentication context");
1361
1362 authctxt->info_req_seen = 1;
1363
1364 name = packet_get_string(NULL);
1365 inst = packet_get_string(NULL);
1366 lang = packet_get_string(NULL);
1367 if (strlen(name) > 0)
1368 logit("%s", name);
1369 if (strlen(inst) > 0)
1370 logit("%s", inst);
1371 free(name);
1372 free(inst);
1373 free(lang);
1374
1375 num_prompts = packet_get_int();
1376 /*
1377 * Begin to build info response packet based on prompts requested.
1378 * We commit to providing the correct number of responses, so if
1379 * further on we run into a problem that prevents this, we have to
1380 * be sure and clean this up and send a correct error response.
1381 */
1382 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1383 packet_put_int(num_prompts);
1384
1385 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1386 for (i = 0; i < num_prompts; i++) {
1387 prompt = packet_get_string(NULL);
1388 echo = packet_get_char();
1389
1390 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1391
1392 packet_put_cstring(response);
1393 explicit_bzero(response, strlen(response));
1394 free(response);
1395 free(prompt);
1396 }
1397 packet_check_eom(); /* done with parsing incoming message. */
1398
1399 packet_add_padding(64);
1400 packet_send();
1401 }
1402
1403 static int
1404 ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1405 u_char *data, u_int datalen)
1406 {
1407 Buffer b;
1408 struct stat st;
1409 pid_t pid;
1410 int to[2], from[2], status, version = 2;
1411
1412 debug2("ssh_keysign called");
1413
1414 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1415 error("ssh_keysign: not installed: %s", strerror(errno));
1416 return -1;
1417 }
1418 if (fflush(stdout) != 0)
1419 error("ssh_keysign: fflush: %s", strerror(errno));
1420 if (pipe(to) < 0) {
1421 error("ssh_keysign: pipe: %s", strerror(errno));
1422 return -1;
1423 }
1424 if (pipe(from) < 0) {
1425 error("ssh_keysign: pipe: %s", strerror(errno));
1426 return -1;
1427 }
1428 if ((pid = fork()) < 0) {
1429 error("ssh_keysign: fork: %s", strerror(errno));
1430 return -1;
1431 }
1432 if (pid == 0) {
1433 /* keep the socket on exec */
1434 fcntl(packet_get_connection_in(), F_SETFD, 0);
1435 permanently_drop_suid(getuid());
1436 close(from[0]);
1437 if (dup2(from[1], STDOUT_FILENO) < 0)
1438 fatal("ssh_keysign: dup2: %s", strerror(errno));
1439 close(to[1]);
1440 if (dup2(to[0], STDIN_FILENO) < 0)
1441 fatal("ssh_keysign: dup2: %s", strerror(errno));
1442 close(from[1]);
1443 close(to[0]);
1444 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1445 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1446 strerror(errno));
1447 }
1448 close(from[1]);
1449 close(to[0]);
1450
1451 buffer_init(&b);
1452 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1453 buffer_put_string(&b, data, datalen);
1454 if (ssh_msg_send(to[1], version, &b) == -1)
1455 fatal("ssh_keysign: couldn't send request");
1456
1457 if (ssh_msg_recv(from[0], &b) < 0) {
1458 error("ssh_keysign: no reply");
1459 buffer_free(&b);
1460 return -1;
1461 }
1462 close(from[0]);
1463 close(to[1]);
1464
1465 while (waitpid(pid, &status, 0) < 0)
1466 if (errno != EINTR)
1467 break;
1468
1469 if (buffer_get_char(&b) != version) {
1470 error("ssh_keysign: bad version");
1471 buffer_free(&b);
1472 return -1;
1473 }
1474 *sigp = buffer_get_string(&b, lenp);
1475 buffer_free(&b);
1476
1477 return 0;
1478 }
1479
1480 int
1481 userauth_hostbased(Authctxt *authctxt)
1482 {
1483 Key *private = NULL;
1484 Sensitive *sensitive = authctxt->sensitive;
1485 Buffer b;
1486 u_char *signature, *blob;
1487 char *chost, *pkalg, *p;
1488 const char *service;
1489 u_int blen, slen;
1490 int ok, i, found = 0;
1491
1492 /* check for a useful key */
1493 for (i = 0; i < sensitive->nkeys; i++) {
1494 private = sensitive->keys[i];
1495 if (private && private->type != KEY_RSA1) {
1496 found = 1;
1497 /* we take and free the key */
1498 sensitive->keys[i] = NULL;
1499 break;
1500 }
1501 }
1502 if (!found) {
1503 debug("No more client hostkeys for hostbased authentication.");
1504 return 0;
1505 }
1506 if (key_to_blob(private, &blob, &blen) == 0) {
1507 key_free(private);
1508 return 0;
1509 }
1510 /* figure out a name for the client host */
1511 p = get_local_name(packet_get_connection_in());
1512 if (p == NULL) {
1513 error("userauth_hostbased: cannot get local ipaddr/name");
1514 key_free(private);
1515 free(blob);
1516 return 0;
1517 }
1518 xasprintf(&chost, "%s.", p);
1519 debug2("userauth_hostbased: chost %s", chost);
1520 free(p);
1521
1522 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1523 authctxt->service;
1524 pkalg = xstrdup(key_ssh_name(private));
1525 buffer_init(&b);
1526 /* construct data */
1527 buffer_put_string(&b, session_id2, session_id2_len);
1528 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1529 buffer_put_cstring(&b, authctxt->server_user);
1530 buffer_put_cstring(&b, service);
1531 buffer_put_cstring(&b, authctxt->method->name);
1532 buffer_put_cstring(&b, pkalg);
1533 buffer_put_string(&b, blob, blen);
1534 buffer_put_cstring(&b, chost);
1535 buffer_put_cstring(&b, authctxt->local_user);
1536 #ifdef DEBUG_PK
1537 buffer_dump(&b);
1538 #endif
1539 if (sensitive->external_keysign)
1540 ok = ssh_keysign(private, &signature, &slen,
1541 buffer_ptr(&b), buffer_len(&b));
1542 else
1543 ok = key_sign(private, &signature, &slen,
1544 buffer_ptr(&b), buffer_len(&b));
1545 key_free(private);
1546 buffer_free(&b);
1547 if (ok != 0) {
1548 error("key_sign failed");
1549 free(chost);
1550 free(pkalg);
1551 free(blob);
1552 return 0;
1553 }
1554 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1555 packet_put_cstring(authctxt->server_user);
1556 packet_put_cstring(authctxt->service);
1557 packet_put_cstring(authctxt->method->name);
1558 packet_put_cstring(pkalg);
1559 packet_put_string(blob, blen);
1560 packet_put_cstring(chost);
1561 packet_put_cstring(authctxt->local_user);
1562 packet_put_string(signature, slen);
1563 explicit_bzero(signature, slen);
1564 free(signature);
1565 free(chost);
1566 free(pkalg);
1567 free(blob);
1568
1569 packet_send();
1570 return 1;
1571 }
1572
1573 /* find auth method */
1574
1575 /*
1576 * given auth method name, if configurable options permit this method fill
1577 * in auth_ident field and return true, otherwise return false.
1578 */
1579 static int
1580 authmethod_is_enabled(Authmethod *method)
1581 {
1582 if (method == NULL)
1583 return 0;
1584 /* return false if options indicate this method is disabled */
1585 if (method->enabled == NULL || *method->enabled == 0)
1586 return 0;
1587 /* return false if batch mode is enabled but method needs interactive mode */
1588 if (method->batch_flag != NULL && *method->batch_flag != 0)
1589 return 0;
1590 return 1;
1591 }
1592
1593 static Authmethod *
1594 authmethod_lookup(const char *name)
1595 {
1596 Authmethod *method = NULL;
1597 if (name != NULL)
1598 for (method = authmethods; method->name != NULL; method++)
1599 if (strcmp(name, method->name) == 0)
1600 return method;
1601 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1602 return NULL;
1603 }
1604
1605 /* XXX internal state */
1606 static Authmethod *current = NULL;
1607 static char *supported = NULL;
1608 static char *preferred = NULL;
1609
1610 /*
1611 * Given the authentication method list sent by the server, return the
1612 * next method we should try. If the server initially sends a nil list,
1613 * use a built-in default list.
1614 */
1615 static Authmethod *
1616 authmethod_get(char *authlist)
1617 {
1618 char *name = NULL;
1619 u_int next;
1620
1621 /* Use a suitable default if we're passed a nil list. */
1622 if (authlist == NULL || strlen(authlist) == 0)
1623 authlist = options.preferred_authentications;
1624
1625 if (supported == NULL || strcmp(authlist, supported) != 0) {
1626 debug3("start over, passed a different list %s", authlist);
1627 free(supported);
1628 supported = xstrdup(authlist);
1629 preferred = options.preferred_authentications;
1630 debug3("preferred %s", preferred);
1631 current = NULL;
1632 } else if (current != NULL && authmethod_is_enabled(current))
1633 return current;
1634
1635 for (;;) {
1636 if ((name = match_list(preferred, supported, &next)) == NULL) {
1637 debug("No more authentication methods to try.");
1638 current = NULL;
1639 return NULL;
1640 }
1641 preferred += next;
1642 debug3("authmethod_lookup %s", name);
1643 debug3("remaining preferred: %s", preferred);
1644 if ((current = authmethod_lookup(name)) != NULL &&
1645 authmethod_is_enabled(current)) {
1646 debug3("authmethod_is_enabled %s", name);
1647 debug("Next authentication method: %s", name);
1648 free(name);
1649 return current;
1650 }
1651 free(name);
1652 }
1653 }
1654
1655 static char *
1656 authmethods_get(void)
1657 {
1658 Authmethod *method = NULL;
1659 Buffer b;
1660 char *list;
1661
1662 buffer_init(&b);
1663 for (method = authmethods; method->name != NULL; method++) {
1664 if (authmethod_is_enabled(method)) {
1665 if (buffer_len(&b) > 0)
1666 buffer_append(&b, ",", 1);
1667 buffer_append(&b, method->name, strlen(method->name));
1668 }
1669 }
1670 buffer_append(&b, "\0", 1);
1671 list = xstrdup(buffer_ptr(&b));
1672 buffer_free(&b);
1673 return list;
1674 }
1675
DragonFly BSD