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hammer2 - Implement error processing and free reserve enforcement
[dragonfly.git] / crypto / openssh / sshconnect2.c
blob5078eb99621425a4be0b5544f03b45d6a44079c1
1 /* $OpenBSD: sshconnect2.c,v 1.247 2016/07/22 05:46:11 dtucker 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 #include "ssherr.h"
74 #include "utf8.h"
75
76 #ifdef GSSAPI
77 #include "ssh-gss.h"
78 #endif
79
80 /* import */
81 extern char *client_version_string;
82 extern char *server_version_string;
83 extern Options options;
84
85 /*
86 * SSH2 key exchange
87 */
88
89 u_char *session_id2 = NULL;
90 u_int session_id2_len = 0;
91
92 char *xxx_host;
93 struct sockaddr *xxx_hostaddr;
94
95 static int
96 verify_host_key_callback(Key *hostkey, struct ssh *ssh)
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 = sshkey_type_from_name(alg)) == KEY_UNSPEC)
135 fatal("%s: unknown alg %s", __func__, alg);
136 if (lookup_key_in_hostkeys_by_type(hostkeys,
137 sshkey_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,
144 (*first == '\0' || *last == '\0') ? "" : ",", last);
145 if (*first != '\0')
146 debug3("%s: prefer hostkeyalgs: %s", __func__, first);
147
148 free(first);
149 free(last);
150 free(hostname);
151 free(oavail);
152 free_hostkeys(hostkeys);
153
154 return ret;
155 }
156
157 void
158 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
159 {
160 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT };
161 char *s;
162 struct kex *kex;
163 int r;
164
165 xxx_host = host;
166 xxx_hostaddr = hostaddr;
167
168 if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL)
169 fatal("%s: kex_names_cat", __func__);
170 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s);
171 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
172 compat_cipher_proposal(options.ciphers);
173 myproposal[PROPOSAL_ENC_ALGS_STOC] =
174 compat_cipher_proposal(options.ciphers);
175 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
176 myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ?
177 "zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib";
178 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
179 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
180 if (options.hostkeyalgorithms != NULL) {
181 if (kex_assemble_names(KEX_DEFAULT_PK_ALG,
182 &options.hostkeyalgorithms) != 0)
183 fatal("%s: kex_assemble_namelist", __func__);
184 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
185 compat_pkalg_proposal(options.hostkeyalgorithms);
186 } else {
187 /* Enforce default */
188 options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG);
189 /* Prefer algorithms that we already have keys for */
190 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
191 compat_pkalg_proposal(
192 order_hostkeyalgs(host, hostaddr, port));
193 }
194
195 if (options.rekey_limit || options.rekey_interval)
196 packet_set_rekey_limits((u_int32_t)options.rekey_limit,
197 (time_t)options.rekey_interval);
198
199 /* start key exchange */
200 if ((r = kex_setup(active_state, myproposal)) != 0)
201 fatal("kex_setup: %s", ssh_err(r));
202 kex = active_state->kex;
203 #ifdef WITH_OPENSSL
204 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
205 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
206 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client;
207 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client;
208 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client;
209 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
210 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
211 # ifdef OPENSSL_HAS_ECC
212 kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
213 # endif
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 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state);
221
222 /* remove ext-info from the KEX proposals for rekeying */
223 myproposal[PROPOSAL_KEX_ALGS] =
224 compat_kex_proposal(options.kex_algorithms);
225 if ((r = kex_prop2buf(kex->my, myproposal)) != 0)
226 fatal("kex_prop2buf: %s", ssh_err(r));
227
228 session_id2 = kex->session_id;
229 session_id2_len = kex->session_id_len;
230
231 #ifdef DEBUG_KEXDH
232 /* send 1st encrypted/maced/compressed message */
233 packet_start(SSH2_MSG_IGNORE);
234 packet_put_cstring("markus");
235 packet_send();
236 packet_write_wait();
237 #endif
238 }
239
240 /*
241 * Authenticate user
242 */
243
244 typedef struct cauthctxt Authctxt;
245 typedef struct cauthmethod Authmethod;
246 typedef struct identity Identity;
247 typedef struct idlist Idlist;
248
249 struct identity {
250 TAILQ_ENTRY(identity) next;
251 int agent_fd; /* >=0 if agent supports key */
252 struct sshkey *key; /* public/private key */
253 char *filename; /* comment for agent-only keys */
254 int tried;
255 int isprivate; /* key points to the private key */
256 int userprovided;
257 };
258 TAILQ_HEAD(idlist, identity);
259
260 struct cauthctxt {
261 const char *server_user;
262 const char *local_user;
263 const char *host;
264 const char *service;
265 struct cauthmethod *method;
266 sig_atomic_t success;
267 char *authlist;
268 int attempt;
269 /* pubkey */
270 struct idlist keys;
271 int agent_fd;
272 /* hostbased */
273 Sensitive *sensitive;
274 char *oktypes, *ktypes;
275 const char *active_ktype;
276 /* kbd-interactive */
277 int info_req_seen;
278 /* generic */
279 void *methoddata;
280 };
281
282 struct cauthmethod {
283 char *name; /* string to compare against server's list */
284 int (*userauth)(Authctxt *authctxt);
285 void (*cleanup)(Authctxt *authctxt);
286 int *enabled; /* flag in option struct that enables method */
287 int *batch_flag; /* flag in option struct that disables method */
288 };
289
290 int input_userauth_service_accept(int, u_int32_t, void *);
291 int input_userauth_ext_info(int, u_int32_t, void *);
292 int input_userauth_success(int, u_int32_t, void *);
293 int input_userauth_success_unexpected(int, u_int32_t, void *);
294 int input_userauth_failure(int, u_int32_t, void *);
295 int input_userauth_banner(int, u_int32_t, void *);
296 int input_userauth_error(int, u_int32_t, void *);
297 int input_userauth_info_req(int, u_int32_t, void *);
298 int input_userauth_pk_ok(int, u_int32_t, void *);
299 int input_userauth_passwd_changereq(int, u_int32_t, void *);
300
301 int userauth_none(Authctxt *);
302 int userauth_pubkey(Authctxt *);
303 int userauth_passwd(Authctxt *);
304 int userauth_kbdint(Authctxt *);
305 int userauth_hostbased(Authctxt *);
306
307 #ifdef GSSAPI
308 int userauth_gssapi(Authctxt *authctxt);
309 int input_gssapi_response(int type, u_int32_t, void *);
310 int input_gssapi_token(int type, u_int32_t, void *);
311 int input_gssapi_hash(int type, u_int32_t, void *);
312 int input_gssapi_error(int, u_int32_t, void *);
313 int input_gssapi_errtok(int, u_int32_t, void *);
314 #endif
315
316 void userauth(Authctxt *, char *);
317
318 static int sign_and_send_pubkey(Authctxt *, Identity *);
319 static void pubkey_prepare(Authctxt *);
320 static void pubkey_cleanup(Authctxt *);
321 static Key *load_identity_file(Identity *);
322
323 static Authmethod *authmethod_get(char *authlist);
324 static Authmethod *authmethod_lookup(const char *name);
325 static char *authmethods_get(void);
326
327 Authmethod authmethods[] = {
328 #ifdef GSSAPI
329 {"gssapi-with-mic",
330 userauth_gssapi,
331 NULL,
332 &options.gss_authentication,
333 NULL},
334 #endif
335 {"hostbased",
336 userauth_hostbased,
337 NULL,
338 &options.hostbased_authentication,
339 NULL},
340 {"publickey",
341 userauth_pubkey,
342 NULL,
343 &options.pubkey_authentication,
344 NULL},
345 {"keyboard-interactive",
346 userauth_kbdint,
347 NULL,
348 &options.kbd_interactive_authentication,
349 &options.batch_mode},
350 {"password",
351 userauth_passwd,
352 NULL,
353 &options.password_authentication,
354 &options.batch_mode},
355 {"none",
356 userauth_none,
357 NULL,
358 NULL,
359 NULL},
360 {NULL, NULL, NULL, NULL, NULL}
361 };
362
363 void
364 ssh_userauth2(const char *local_user, const char *server_user, char *host,
365 Sensitive *sensitive)
366 {
367 struct ssh *ssh = active_state;
368 Authctxt authctxt;
369 int r;
370
371 if (options.challenge_response_authentication)
372 options.kbd_interactive_authentication = 1;
373 if (options.preferred_authentications == NULL)
374 options.preferred_authentications = authmethods_get();
375
376 /* setup authentication context */
377 memset(&authctxt, 0, sizeof(authctxt));
378 pubkey_prepare(&authctxt);
379 authctxt.server_user = server_user;
380 authctxt.local_user = local_user;
381 authctxt.host = host;
382 authctxt.service = "ssh-connection"; /* service name */
383 authctxt.success = 0;
384 authctxt.method = authmethod_lookup("none");
385 authctxt.authlist = NULL;
386 authctxt.methoddata = NULL;
387 authctxt.sensitive = sensitive;
388 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL;
389 authctxt.info_req_seen = 0;
390 authctxt.agent_fd = -1;
391 if (authctxt.method == NULL)
392 fatal("ssh_userauth2: internal error: cannot send userauth none request");
393
394 if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 ||
395 (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 ||
396 (r = sshpkt_send(ssh)) != 0)
397 fatal("%s: %s", __func__, ssh_err(r));
398
399 ssh_dispatch_init(ssh, &input_userauth_error);
400 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info);
401 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept);
402 ssh_dispatch_run(ssh, DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
403
404 pubkey_cleanup(&authctxt);
405 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
406
407 debug("Authentication succeeded (%s).", authctxt.method->name);
408 }
409
410 /* ARGSUSED */
411 int
412 input_userauth_service_accept(int type, u_int32_t seqnr, void *ctxt)
413 {
414 Authctxt *authctxt = ctxt;
415 struct ssh *ssh = active_state;
416 int r;
417
418 if (ssh_packet_remaining(ssh) > 0) {
419 char *reply;
420
421 if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0)
422 goto out;
423 debug2("service_accept: %s", reply);
424 free(reply);
425 } else {
426 debug2("buggy server: service_accept w/o service");
427 }
428 if ((r = sshpkt_get_end(ssh)) != 0)
429 goto out;
430 debug("SSH2_MSG_SERVICE_ACCEPT received");
431
432 /* initial userauth request */
433 userauth_none(authctxt);
434
435 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error);
436 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
437 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
438 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
439 r = 0;
440 out:
441 return r;
442 }
443
444 /* ARGSUSED */
445 int
446 input_userauth_ext_info(int type, u_int32_t seqnr, void *ctxt)
447 {
448 return kex_input_ext_info(type, seqnr, active_state);
449 }
450
451 void
452 userauth(Authctxt *authctxt, char *authlist)
453 {
454 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
455 authctxt->method->cleanup(authctxt);
456
457 free(authctxt->methoddata);
458 authctxt->methoddata = NULL;
459 if (authlist == NULL) {
460 authlist = authctxt->authlist;
461 } else {
462 free(authctxt->authlist);
463 authctxt->authlist = authlist;
464 }
465 for (;;) {
466 Authmethod *method = authmethod_get(authlist);
467 if (method == NULL)
468 fatal("Permission denied (%s).", authlist);
469 authctxt->method = method;
470
471 /* reset the per method handler */
472 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
473 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
474
475 /* and try new method */
476 if (method->userauth(authctxt) != 0) {
477 debug2("we sent a %s packet, wait for reply", method->name);
478 break;
479 } else {
480 debug2("we did not send a packet, disable method");
481 method->enabled = NULL;
482 }
483 }
484 }
485
486 /* ARGSUSED */
487 int
488 input_userauth_error(int type, u_int32_t seq, void *ctxt)
489 {
490 fatal("input_userauth_error: bad message during authentication: "
491 "type %d", type);
492 return 0;
493 }
494
495 /* ARGSUSED */
496 int
497 input_userauth_banner(int type, u_int32_t seq, void *ctxt)
498 {
499 char *msg, *lang;
500 u_int len;
501
502 debug3("%s", __func__);
503 msg = packet_get_string(&len);
504 lang = packet_get_string(NULL);
505 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO)
506 fmprintf(stderr, "%s", msg);
507 free(msg);
508 free(lang);
509 return 0;
510 }
511
512 /* ARGSUSED */
513 int
514 input_userauth_success(int type, u_int32_t seq, void *ctxt)
515 {
516 Authctxt *authctxt = ctxt;
517
518 if (authctxt == NULL)
519 fatal("input_userauth_success: no authentication context");
520 free(authctxt->authlist);
521 authctxt->authlist = NULL;
522 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
523 authctxt->method->cleanup(authctxt);
524 free(authctxt->methoddata);
525 authctxt->methoddata = NULL;
526 authctxt->success = 1; /* break out */
527 return 0;
528 }
529
530 int
531 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt)
532 {
533 Authctxt *authctxt = ctxt;
534
535 if (authctxt == NULL)
536 fatal("%s: no authentication context", __func__);
537
538 fatal("Unexpected authentication success during %s.",
539 authctxt->method->name);
540 return 0;
541 }
542
543 /* ARGSUSED */
544 int
545 input_userauth_failure(int type, u_int32_t seq, void *ctxt)
546 {
547 Authctxt *authctxt = ctxt;
548 char *authlist = NULL;
549 int partial;
550
551 if (authctxt == NULL)
552 fatal("input_userauth_failure: no authentication context");
553
554 authlist = packet_get_string(NULL);
555 partial = packet_get_char();
556 packet_check_eom();
557
558 if (partial != 0) {
559 verbose("Authenticated with partial success.");
560 /* reset state */
561 pubkey_cleanup(authctxt);
562 pubkey_prepare(authctxt);
563 }
564 debug("Authentications that can continue: %s", authlist);
565
566 userauth(authctxt, authlist);
567 return 0;
568 }
569
570 /* ARGSUSED */
571 int
572 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
573 {
574 Authctxt *authctxt = ctxt;
575 Key *key = NULL;
576 Identity *id = NULL;
577 Buffer b;
578 int pktype, sent = 0;
579 u_int alen, blen;
580 char *pkalg, *fp;
581 u_char *pkblob;
582
583 if (authctxt == NULL)
584 fatal("input_userauth_pk_ok: no authentication context");
585 if (datafellows & SSH_BUG_PKOK) {
586 /* this is similar to SSH_BUG_PKAUTH */
587 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
588 pkblob = packet_get_string(&blen);
589 buffer_init(&b);
590 buffer_append(&b, pkblob, blen);
591 pkalg = buffer_get_string(&b, &alen);
592 buffer_free(&b);
593 } else {
594 pkalg = packet_get_string(&alen);
595 pkblob = packet_get_string(&blen);
596 }
597 packet_check_eom();
598
599 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
600
601 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
602 debug("unknown pkalg %s", pkalg);
603 goto done;
604 }
605 if ((key = key_from_blob(pkblob, blen)) == NULL) {
606 debug("no key from blob. pkalg %s", pkalg);
607 goto done;
608 }
609 if (key->type != pktype) {
610 error("input_userauth_pk_ok: type mismatch "
611 "for decoded key (received %d, expected %d)",
612 key->type, pktype);
613 goto done;
614 }
615 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash,
616 SSH_FP_DEFAULT)) == NULL)
617 goto done;
618 debug2("input_userauth_pk_ok: fp %s", fp);
619 free(fp);
620
621 /*
622 * search keys in the reverse order, because last candidate has been
623 * moved to the end of the queue. this also avoids confusion by
624 * duplicate keys
625 */
626 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
627 if (key_equal(key, id->key)) {
628 sent = sign_and_send_pubkey(authctxt, id);
629 break;
630 }
631 }
632 done:
633 if (key != NULL)
634 key_free(key);
635 free(pkalg);
636 free(pkblob);
637
638 /* try another method if we did not send a packet */
639 if (sent == 0)
640 userauth(authctxt, NULL);
641 return 0;
642 }
643
644 #ifdef GSSAPI
645 int
646 userauth_gssapi(Authctxt *authctxt)
647 {
648 Gssctxt *gssctxt = NULL;
649 static gss_OID_set gss_supported = NULL;
650 static u_int mech = 0;
651 OM_uint32 min;
652 int ok = 0;
653
654 /* Try one GSSAPI method at a time, rather than sending them all at
655 * once. */
656
657 if (gss_supported == NULL)
658 gss_indicate_mechs(&min, &gss_supported);
659
660 /* Check to see if the mechanism is usable before we offer it */
661 while (mech < gss_supported->count && !ok) {
662 /* My DER encoding requires length<128 */
663 if (gss_supported->elements[mech].length < 128 &&
664 ssh_gssapi_check_mechanism(&gssctxt,
665 &gss_supported->elements[mech], authctxt->host)) {
666 ok = 1; /* Mechanism works */
667 } else {
668 mech++;
669 }
670 }
671
672 if (!ok)
673 return 0;
674
675 authctxt->methoddata=(void *)gssctxt;
676
677 packet_start(SSH2_MSG_USERAUTH_REQUEST);
678 packet_put_cstring(authctxt->server_user);
679 packet_put_cstring(authctxt->service);
680 packet_put_cstring(authctxt->method->name);
681
682 packet_put_int(1);
683
684 packet_put_int((gss_supported->elements[mech].length) + 2);
685 packet_put_char(SSH_GSS_OIDTYPE);
686 packet_put_char(gss_supported->elements[mech].length);
687 packet_put_raw(gss_supported->elements[mech].elements,
688 gss_supported->elements[mech].length);
689
690 packet_send();
691
692 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
693 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
694 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
695 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
696
697 mech++; /* Move along to next candidate */
698
699 return 1;
700 }
701
702 static OM_uint32
703 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
704 {
705 Authctxt *authctxt = ctxt;
706 Gssctxt *gssctxt = authctxt->methoddata;
707 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
708 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
709 gss_buffer_desc gssbuf;
710 OM_uint32 status, ms, flags;
711 Buffer b;
712
713 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
714 recv_tok, &send_tok, &flags);
715
716 if (send_tok.length > 0) {
717 if (GSS_ERROR(status))
718 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
719 else
720 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
721
722 packet_put_string(send_tok.value, send_tok.length);
723 packet_send();
724 gss_release_buffer(&ms, &send_tok);
725 }
726
727 if (status == GSS_S_COMPLETE) {
728 /* send either complete or MIC, depending on mechanism */
729 if (!(flags & GSS_C_INTEG_FLAG)) {
730 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
731 packet_send();
732 } else {
733 ssh_gssapi_buildmic(&b, authctxt->server_user,
734 authctxt->service, "gssapi-with-mic");
735
736 gssbuf.value = buffer_ptr(&b);
737 gssbuf.length = buffer_len(&b);
738
739 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
740
741 if (!GSS_ERROR(status)) {
742 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
743 packet_put_string(mic.value, mic.length);
744
745 packet_send();
746 }
747
748 buffer_free(&b);
749 gss_release_buffer(&ms, &mic);
750 }
751 }
752
753 return status;
754 }
755
756 /* ARGSUSED */
757 int
758 input_gssapi_response(int type, u_int32_t plen, void *ctxt)
759 {
760 Authctxt *authctxt = ctxt;
761 Gssctxt *gssctxt;
762 int oidlen;
763 char *oidv;
764
765 if (authctxt == NULL)
766 fatal("input_gssapi_response: no authentication context");
767 gssctxt = authctxt->methoddata;
768
769 /* Setup our OID */
770 oidv = packet_get_string(&oidlen);
771
772 if (oidlen <= 2 ||
773 oidv[0] != SSH_GSS_OIDTYPE ||
774 oidv[1] != oidlen - 2) {
775 free(oidv);
776 debug("Badly encoded mechanism OID received");
777 userauth(authctxt, NULL);
778 return 0;
779 }
780
781 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
782 fatal("Server returned different OID than expected");
783
784 packet_check_eom();
785
786 free(oidv);
787
788 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
789 /* Start again with next method on list */
790 debug("Trying to start again");
791 userauth(authctxt, NULL);
792 return 0;
793 }
794 return 0;
795 }
796
797 /* ARGSUSED */
798 int
799 input_gssapi_token(int type, u_int32_t plen, void *ctxt)
800 {
801 Authctxt *authctxt = ctxt;
802 gss_buffer_desc recv_tok;
803 OM_uint32 status;
804 u_int slen;
805
806 if (authctxt == NULL)
807 fatal("input_gssapi_response: no authentication context");
808
809 recv_tok.value = packet_get_string(&slen);
810 recv_tok.length = slen; /* safe typecast */
811
812 packet_check_eom();
813
814 status = process_gssapi_token(ctxt, &recv_tok);
815
816 free(recv_tok.value);
817
818 if (GSS_ERROR(status)) {
819 /* Start again with the next method in the list */
820 userauth(authctxt, NULL);
821 return 0;
822 }
823 return 0;
824 }
825
826 /* ARGSUSED */
827 int
828 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
829 {
830 Authctxt *authctxt = ctxt;
831 Gssctxt *gssctxt;
832 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
833 gss_buffer_desc recv_tok;
834 OM_uint32 ms;
835 u_int len;
836
837 if (authctxt == NULL)
838 fatal("input_gssapi_response: no authentication context");
839 gssctxt = authctxt->methoddata;
840
841 recv_tok.value = packet_get_string(&len);
842 recv_tok.length = len;
843
844 packet_check_eom();
845
846 /* Stick it into GSSAPI and see what it says */
847 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
848 &recv_tok, &send_tok, NULL);
849
850 free(recv_tok.value);
851 gss_release_buffer(&ms, &send_tok);
852
853 /* Server will be returning a failed packet after this one */
854 return 0;
855 }
856
857 /* ARGSUSED */
858 int
859 input_gssapi_error(int type, u_int32_t plen, void *ctxt)
860 {
861 char *msg;
862 char *lang;
863
864 /* maj */(void)packet_get_int();
865 /* min */(void)packet_get_int();
866 msg=packet_get_string(NULL);
867 lang=packet_get_string(NULL);
868
869 packet_check_eom();
870
871 debug("Server GSSAPI Error:\n%s", msg);
872 free(msg);
873 free(lang);
874 return 0;
875 }
876 #endif /* GSSAPI */
877
878 int
879 userauth_none(Authctxt *authctxt)
880 {
881 /* initial userauth request */
882 packet_start(SSH2_MSG_USERAUTH_REQUEST);
883 packet_put_cstring(authctxt->server_user);
884 packet_put_cstring(authctxt->service);
885 packet_put_cstring(authctxt->method->name);
886 packet_send();
887 return 1;
888 }
889
890 int
891 userauth_passwd(Authctxt *authctxt)
892 {
893 static int attempt = 0;
894 char prompt[150];
895 char *password;
896 const char *host = options.host_key_alias ? options.host_key_alias :
897 authctxt->host;
898
899 if (attempt++ >= options.number_of_password_prompts)
900 return 0;
901
902 if (attempt != 1)
903 error("Permission denied, please try again.");
904
905 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
906 authctxt->server_user, host);
907 password = read_passphrase(prompt, 0);
908 packet_start(SSH2_MSG_USERAUTH_REQUEST);
909 packet_put_cstring(authctxt->server_user);
910 packet_put_cstring(authctxt->service);
911 packet_put_cstring(authctxt->method->name);
912 packet_put_char(0);
913 packet_put_cstring(password);
914 explicit_bzero(password, strlen(password));
915 free(password);
916 packet_add_padding(64);
917 packet_send();
918
919 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
920 &input_userauth_passwd_changereq);
921
922 return 1;
923 }
924
925 /*
926 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
927 */
928 /* ARGSUSED */
929 int
930 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
931 {
932 Authctxt *authctxt = ctxt;
933 char *info, *lang, *password = NULL, *retype = NULL;
934 char prompt[150];
935 const char *host = options.host_key_alias ? options.host_key_alias :
936 authctxt->host;
937
938 debug2("input_userauth_passwd_changereq");
939
940 if (authctxt == NULL)
941 fatal("input_userauth_passwd_changereq: "
942 "no authentication context");
943
944 info = packet_get_string(NULL);
945 lang = packet_get_string(NULL);
946 if (strlen(info) > 0)
947 logit("%s", info);
948 free(info);
949 free(lang);
950 packet_start(SSH2_MSG_USERAUTH_REQUEST);
951 packet_put_cstring(authctxt->server_user);
952 packet_put_cstring(authctxt->service);
953 packet_put_cstring(authctxt->method->name);
954 packet_put_char(1); /* additional info */
955 snprintf(prompt, sizeof(prompt),
956 "Enter %.30s@%.128s's old password: ",
957 authctxt->server_user, host);
958 password = read_passphrase(prompt, 0);
959 packet_put_cstring(password);
960 explicit_bzero(password, strlen(password));
961 free(password);
962 password = NULL;
963 while (password == NULL) {
964 snprintf(prompt, sizeof(prompt),
965 "Enter %.30s@%.128s's new password: ",
966 authctxt->server_user, host);
967 password = read_passphrase(prompt, RP_ALLOW_EOF);
968 if (password == NULL) {
969 /* bail out */
970 return 0;
971 }
972 snprintf(prompt, sizeof(prompt),
973 "Retype %.30s@%.128s's new password: ",
974 authctxt->server_user, host);
975 retype = read_passphrase(prompt, 0);
976 if (strcmp(password, retype) != 0) {
977 explicit_bzero(password, strlen(password));
978 free(password);
979 logit("Mismatch; try again, EOF to quit.");
980 password = NULL;
981 }
982 explicit_bzero(retype, strlen(retype));
983 free(retype);
984 }
985 packet_put_cstring(password);
986 explicit_bzero(password, strlen(password));
987 free(password);
988 packet_add_padding(64);
989 packet_send();
990
991 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
992 &input_userauth_passwd_changereq);
993 return 0;
994 }
995
996 static const char *
997 identity_sign_encode(struct identity *id)
998 {
999 struct ssh *ssh = active_state;
1000
1001 if (id->key->type == KEY_RSA) {
1002 switch (ssh->kex->rsa_sha2) {
1003 case 256:
1004 return "rsa-sha2-256";
1005 case 512:
1006 return "rsa-sha2-512";
1007 }
1008 }
1009 return key_ssh_name(id->key);
1010 }
1011
1012 static int
1013 identity_sign(struct identity *id, u_char **sigp, size_t *lenp,
1014 const u_char *data, size_t datalen, u_int compat)
1015 {
1016 Key *prv;
1017 int ret;
1018 const char *alg;
1019
1020 alg = identity_sign_encode(id);
1021
1022 /* the agent supports this key */
1023 if (id->agent_fd != -1)
1024 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp,
1025 data, datalen, alg, compat);
1026
1027 /*
1028 * we have already loaded the private key or
1029 * the private key is stored in external hardware
1030 */
1031 if (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))
1032 return (sshkey_sign(id->key, sigp, lenp, data, datalen, alg,
1033 compat));
1034 /* load the private key from the file */
1035 if ((prv = load_identity_file(id)) == NULL)
1036 return SSH_ERR_KEY_NOT_FOUND;
1037 ret = sshkey_sign(prv, sigp, lenp, data, datalen, alg, compat);
1038 sshkey_free(prv);
1039 return (ret);
1040 }
1041
1042 static int
1043 sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1044 {
1045 Buffer b;
1046 Identity *private_id;
1047 u_char *blob, *signature;
1048 size_t slen;
1049 u_int bloblen, skip = 0;
1050 int matched, ret = -1, have_sig = 1;
1051 char *fp;
1052
1053 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash,
1054 SSH_FP_DEFAULT)) == NULL)
1055 return 0;
1056 debug3("%s: %s %s", __func__, key_type(id->key), fp);
1057 free(fp);
1058
1059 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1060 /* we cannot handle this key */
1061 debug3("sign_and_send_pubkey: cannot handle key");
1062 return 0;
1063 }
1064 /* data to be signed */
1065 buffer_init(&b);
1066 if (datafellows & SSH_OLD_SESSIONID) {
1067 buffer_append(&b, session_id2, session_id2_len);
1068 skip = session_id2_len;
1069 } else {
1070 buffer_put_string(&b, session_id2, session_id2_len);
1071 skip = buffer_len(&b);
1072 }
1073 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1074 buffer_put_cstring(&b, authctxt->server_user);
1075 buffer_put_cstring(&b,
1076 datafellows & SSH_BUG_PKSERVICE ?
1077 "ssh-userauth" :
1078 authctxt->service);
1079 if (datafellows & SSH_BUG_PKAUTH) {
1080 buffer_put_char(&b, have_sig);
1081 } else {
1082 buffer_put_cstring(&b, authctxt->method->name);
1083 buffer_put_char(&b, have_sig);
1084 buffer_put_cstring(&b, identity_sign_encode(id));
1085 }
1086 buffer_put_string(&b, blob, bloblen);
1087
1088 /*
1089 * If the key is an certificate, try to find a matching private key
1090 * and use it to complete the signature.
1091 * If no such private key exists, fall back to trying the certificate
1092 * key itself in case it has a private half already loaded.
1093 */
1094 if (key_is_cert(id->key)) {
1095 matched = 0;
1096 TAILQ_FOREACH(private_id, &authctxt->keys, next) {
1097 if (sshkey_equal_public(id->key, private_id->key) &&
1098 id->key->type != private_id->key->type) {
1099 id = private_id;
1100 matched = 1;
1101 break;
1102 }
1103 }
1104 if (matched) {
1105 debug2("%s: using private key \"%s\"%s for "
1106 "certificate", __func__, id->filename,
1107 id->agent_fd != -1 ? " from agent" : "");
1108 } else {
1109 debug("%s: no separate private key for certificate "
1110 "\"%s\"", __func__, id->filename);
1111 }
1112 }
1113
1114 /* generate signature */
1115 ret = identity_sign(id, &signature, &slen,
1116 buffer_ptr(&b), buffer_len(&b), datafellows);
1117 if (ret != 0) {
1118 if (ret != SSH_ERR_KEY_NOT_FOUND)
1119 error("%s: signing failed: %s", __func__, ssh_err(ret));
1120 free(blob);
1121 buffer_free(&b);
1122 return 0;
1123 }
1124 #ifdef DEBUG_PK
1125 buffer_dump(&b);
1126 #endif
1127 if (datafellows & SSH_BUG_PKSERVICE) {
1128 buffer_clear(&b);
1129 buffer_append(&b, session_id2, session_id2_len);
1130 skip = session_id2_len;
1131 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1132 buffer_put_cstring(&b, authctxt->server_user);
1133 buffer_put_cstring(&b, authctxt->service);
1134 buffer_put_cstring(&b, authctxt->method->name);
1135 buffer_put_char(&b, have_sig);
1136 if (!(datafellows & SSH_BUG_PKAUTH))
1137 buffer_put_cstring(&b, key_ssh_name(id->key));
1138 buffer_put_string(&b, blob, bloblen);
1139 }
1140 free(blob);
1141
1142 /* append signature */
1143 buffer_put_string(&b, signature, slen);
1144 free(signature);
1145
1146 /* skip session id and packet type */
1147 if (buffer_len(&b) < skip + 1)
1148 fatal("userauth_pubkey: internal error");
1149 buffer_consume(&b, skip + 1);
1150
1151 /* put remaining data from buffer into packet */
1152 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1153 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1154 buffer_free(&b);
1155 packet_send();
1156
1157 return 1;
1158 }
1159
1160 static int
1161 send_pubkey_test(Authctxt *authctxt, Identity *id)
1162 {
1163 u_char *blob;
1164 u_int bloblen, have_sig = 0;
1165
1166 debug3("send_pubkey_test");
1167
1168 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1169 /* we cannot handle this key */
1170 debug3("send_pubkey_test: cannot handle key");
1171 return 0;
1172 }
1173 /* register callback for USERAUTH_PK_OK message */
1174 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1175
1176 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1177 packet_put_cstring(authctxt->server_user);
1178 packet_put_cstring(authctxt->service);
1179 packet_put_cstring(authctxt->method->name);
1180 packet_put_char(have_sig);
1181 if (!(datafellows & SSH_BUG_PKAUTH))
1182 packet_put_cstring(identity_sign_encode(id));
1183 packet_put_string(blob, bloblen);
1184 free(blob);
1185 packet_send();
1186 return 1;
1187 }
1188
1189 static Key *
1190 load_identity_file(Identity *id)
1191 {
1192 Key *private = NULL;
1193 char prompt[300], *passphrase, *comment;
1194 int r, perm_ok = 0, quit = 0, i;
1195 struct stat st;
1196
1197 if (stat(id->filename, &st) < 0) {
1198 (id->userprovided ? logit : debug3)("no such identity: %s: %s",
1199 id->filename, strerror(errno));
1200 return NULL;
1201 }
1202 snprintf(prompt, sizeof prompt,
1203 "Enter passphrase for key '%.100s': ", id->filename);
1204 for (i = 0; i <= options.number_of_password_prompts; i++) {
1205 if (i == 0)
1206 passphrase = "";
1207 else {
1208 passphrase = read_passphrase(prompt, 0);
1209 if (*passphrase == '\0') {
1210 debug2("no passphrase given, try next key");
1211 free(passphrase);
1212 break;
1213 }
1214 }
1215 switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename,
1216 passphrase, &private, &comment, &perm_ok))) {
1217 case 0:
1218 break;
1219 case SSH_ERR_KEY_WRONG_PASSPHRASE:
1220 if (options.batch_mode) {
1221 quit = 1;
1222 break;
1223 }
1224 if (i != 0)
1225 debug2("bad passphrase given, try again...");
1226 break;
1227 case SSH_ERR_SYSTEM_ERROR:
1228 if (errno == ENOENT) {
1229 debug2("Load key \"%s\": %s",
1230 id->filename, ssh_err(r));
1231 quit = 1;
1232 break;
1233 }
1234 /* FALLTHROUGH */
1235 default:
1236 error("Load key \"%s\": %s", id->filename, ssh_err(r));
1237 quit = 1;
1238 break;
1239 }
1240 if (!quit && private != NULL && id->agent_fd == -1 &&
1241 !(id->key && id->isprivate))
1242 maybe_add_key_to_agent(id->filename, private, comment,
1243 passphrase);
1244 if (i > 0) {
1245 explicit_bzero(passphrase, strlen(passphrase));
1246 free(passphrase);
1247 }
1248 free(comment);
1249 if (private != NULL || quit)
1250 break;
1251 }
1252 return private;
1253 }
1254
1255 /*
1256 * try keys in the following order:
1257 * 1. certificates listed in the config file
1258 * 2. other input certificates
1259 * 3. agent keys that are found in the config file
1260 * 4. other agent keys
1261 * 5. keys that are only listed in the config file
1262 */
1263 static void
1264 pubkey_prepare(Authctxt *authctxt)
1265 {
1266 struct identity *id, *id2, *tmp;
1267 struct idlist agent, files, *preferred;
1268 struct sshkey *key;
1269 int agent_fd = -1, i, r, found;
1270 size_t j;
1271 struct ssh_identitylist *idlist;
1272
1273 TAILQ_INIT(&agent); /* keys from the agent */
1274 TAILQ_INIT(&files); /* keys from the config file */
1275 preferred = &authctxt->keys;
1276 TAILQ_INIT(preferred); /* preferred order of keys */
1277
1278 /* list of keys stored in the filesystem and PKCS#11 */
1279 for (i = 0; i < options.num_identity_files; i++) {
1280 key = options.identity_keys[i];
1281 if (key && key->type == KEY_RSA1)
1282 continue;
1283 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER)
1284 continue;
1285 options.identity_keys[i] = NULL;
1286 id = xcalloc(1, sizeof(*id));
1287 id->agent_fd = -1;
1288 id->key = key;
1289 id->filename = xstrdup(options.identity_files[i]);
1290 id->userprovided = options.identity_file_userprovided[i];
1291 TAILQ_INSERT_TAIL(&files, id, next);
1292 }
1293 /* list of certificates specified by user */
1294 for (i = 0; i < options.num_certificate_files; i++) {
1295 key = options.certificates[i];
1296 if (!key_is_cert(key) || key->cert == NULL ||
1297 key->cert->type != SSH2_CERT_TYPE_USER)
1298 continue;
1299 id = xcalloc(1, sizeof(*id));
1300 id->agent_fd = -1;
1301 id->key = key;
1302 id->filename = xstrdup(options.certificate_files[i]);
1303 id->userprovided = options.certificate_file_userprovided[i];
1304 TAILQ_INSERT_TAIL(preferred, id, next);
1305 }
1306 /* list of keys supported by the agent */
1307 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) {
1308 if (r != SSH_ERR_AGENT_NOT_PRESENT)
1309 debug("%s: ssh_get_authentication_socket: %s",
1310 __func__, ssh_err(r));
1311 } else if ((r = ssh_fetch_identitylist(agent_fd, 2, &idlist)) != 0) {
1312 if (r != SSH_ERR_AGENT_NO_IDENTITIES)
1313 debug("%s: ssh_fetch_identitylist: %s",
1314 __func__, ssh_err(r));
1315 close(agent_fd);
1316 } else {
1317 for (j = 0; j < idlist->nkeys; j++) {
1318 found = 0;
1319 TAILQ_FOREACH(id, &files, next) {
1320 /*
1321 * agent keys from the config file are
1322 * preferred
1323 */
1324 if (sshkey_equal(idlist->keys[j], id->key)) {
1325 TAILQ_REMOVE(&files, id, next);
1326 TAILQ_INSERT_TAIL(preferred, id, next);
1327 id->agent_fd = agent_fd;
1328 found = 1;
1329 break;
1330 }
1331 }
1332 if (!found && !options.identities_only) {
1333 id = xcalloc(1, sizeof(*id));
1334 /* XXX "steals" key/comment from idlist */
1335 id->key = idlist->keys[j];
1336 id->filename = idlist->comments[j];
1337 idlist->keys[j] = NULL;
1338 idlist->comments[j] = NULL;
1339 id->agent_fd = agent_fd;
1340 TAILQ_INSERT_TAIL(&agent, id, next);
1341 }
1342 }
1343 ssh_free_identitylist(idlist);
1344 /* append remaining agent keys */
1345 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1346 TAILQ_REMOVE(&agent, id, next);
1347 TAILQ_INSERT_TAIL(preferred, id, next);
1348 }
1349 authctxt->agent_fd = agent_fd;
1350 }
1351 /* Prefer PKCS11 keys that are explicitly listed */
1352 TAILQ_FOREACH_SAFE(id, &files, next, tmp) {
1353 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0)
1354 continue;
1355 found = 0;
1356 TAILQ_FOREACH(id2, &files, next) {
1357 if (id2->key == NULL ||
1358 (id2->key->flags & SSHKEY_FLAG_EXT) == 0)
1359 continue;
1360 if (sshkey_equal(id->key, id2->key)) {
1361 TAILQ_REMOVE(&files, id, next);
1362 TAILQ_INSERT_TAIL(preferred, id, next);
1363 found = 1;
1364 break;
1365 }
1366 }
1367 /* If IdentitiesOnly set and key not found then don't use it */
1368 if (!found && options.identities_only) {
1369 TAILQ_REMOVE(&files, id, next);
1370 explicit_bzero(id, sizeof(*id));
1371 free(id);
1372 }
1373 }
1374 /* append remaining keys from the config file */
1375 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1376 TAILQ_REMOVE(&files, id, next);
1377 TAILQ_INSERT_TAIL(preferred, id, next);
1378 }
1379 /* finally, filter by PubkeyAcceptedKeyTypes */
1380 TAILQ_FOREACH_SAFE(id, preferred, next, id2) {
1381 if (id->key != NULL &&
1382 match_pattern_list(sshkey_ssh_name(id->key),
1383 options.pubkey_key_types, 0) != 1) {
1384 debug("Skipping %s key %s - "
1385 "not in PubkeyAcceptedKeyTypes",
1386 sshkey_ssh_name(id->key), id->filename);
1387 TAILQ_REMOVE(preferred, id, next);
1388 sshkey_free(id->key);
1389 free(id->filename);
1390 memset(id, 0, sizeof(*id));
1391 continue;
1392 }
1393 debug2("key: %s (%p)%s%s", id->filename, id->key,
1394 id->userprovided ? ", explicit" : "",
1395 id->agent_fd != -1 ? ", agent" : "");
1396 }
1397 }
1398
1399 static void
1400 pubkey_cleanup(Authctxt *authctxt)
1401 {
1402 Identity *id;
1403
1404 if (authctxt->agent_fd != -1)
1405 ssh_close_authentication_socket(authctxt->agent_fd);
1406 for (id = TAILQ_FIRST(&authctxt->keys); id;
1407 id = TAILQ_FIRST(&authctxt->keys)) {
1408 TAILQ_REMOVE(&authctxt->keys, id, next);
1409 sshkey_free(id->key);
1410 free(id->filename);
1411 free(id);
1412 }
1413 }
1414
1415 static int
1416 try_identity(Identity *id)
1417 {
1418 if (!id->key)
1419 return (0);
1420 if (key_type_plain(id->key->type) == KEY_RSA &&
1421 (datafellows & SSH_BUG_RSASIGMD5) != 0) {
1422 debug("Skipped %s key %s for RSA/MD5 server",
1423 key_type(id->key), id->filename);
1424 return (0);
1425 }
1426 return (id->key->type != KEY_RSA1);
1427 }
1428
1429 int
1430 userauth_pubkey(Authctxt *authctxt)
1431 {
1432 Identity *id;
1433 int sent = 0;
1434
1435 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1436 if (id->tried++)
1437 return (0);
1438 /* move key to the end of the queue */
1439 TAILQ_REMOVE(&authctxt->keys, id, next);
1440 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1441 /*
1442 * send a test message if we have the public key. for
1443 * encrypted keys we cannot do this and have to load the
1444 * private key instead
1445 */
1446 if (id->key != NULL) {
1447 if (try_identity(id)) {
1448 debug("Offering %s public key: %s",
1449 key_type(id->key), id->filename);
1450 sent = send_pubkey_test(authctxt, id);
1451 }
1452 } else {
1453 debug("Trying private key: %s", id->filename);
1454 id->key = load_identity_file(id);
1455 if (id->key != NULL) {
1456 if (try_identity(id)) {
1457 id->isprivate = 1;
1458 sent = sign_and_send_pubkey(
1459 authctxt, id);
1460 }
1461 key_free(id->key);
1462 id->key = NULL;
1463 }
1464 }
1465 if (sent)
1466 return (sent);
1467 }
1468 return (0);
1469 }
1470
1471 /*
1472 * Send userauth request message specifying keyboard-interactive method.
1473 */
1474 int
1475 userauth_kbdint(Authctxt *authctxt)
1476 {
1477 static int attempt = 0;
1478
1479 if (attempt++ >= options.number_of_password_prompts)
1480 return 0;
1481 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1482 if (attempt > 1 && !authctxt->info_req_seen) {
1483 debug3("userauth_kbdint: disable: no info_req_seen");
1484 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1485 return 0;
1486 }
1487
1488 debug2("userauth_kbdint");
1489 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1490 packet_put_cstring(authctxt->server_user);
1491 packet_put_cstring(authctxt->service);
1492 packet_put_cstring(authctxt->method->name);
1493 packet_put_cstring(""); /* lang */
1494 packet_put_cstring(options.kbd_interactive_devices ?
1495 options.kbd_interactive_devices : "");
1496 packet_send();
1497
1498 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1499 return 1;
1500 }
1501
1502 /*
1503 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1504 */
1505 int
1506 input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1507 {
1508 Authctxt *authctxt = ctxt;
1509 char *name, *inst, *lang, *prompt, *response;
1510 u_int num_prompts, i;
1511 int echo = 0;
1512
1513 debug2("input_userauth_info_req");
1514
1515 if (authctxt == NULL)
1516 fatal("input_userauth_info_req: no authentication context");
1517
1518 authctxt->info_req_seen = 1;
1519
1520 name = packet_get_string(NULL);
1521 inst = packet_get_string(NULL);
1522 lang = packet_get_string(NULL);
1523 if (strlen(name) > 0)
1524 logit("%s", name);
1525 if (strlen(inst) > 0)
1526 logit("%s", inst);
1527 free(name);
1528 free(inst);
1529 free(lang);
1530
1531 num_prompts = packet_get_int();
1532 /*
1533 * Begin to build info response packet based on prompts requested.
1534 * We commit to providing the correct number of responses, so if
1535 * further on we run into a problem that prevents this, we have to
1536 * be sure and clean this up and send a correct error response.
1537 */
1538 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1539 packet_put_int(num_prompts);
1540
1541 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1542 for (i = 0; i < num_prompts; i++) {
1543 prompt = packet_get_string(NULL);
1544 echo = packet_get_char();
1545
1546 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1547
1548 packet_put_cstring(response);
1549 explicit_bzero(response, strlen(response));
1550 free(response);
1551 free(prompt);
1552 }
1553 packet_check_eom(); /* done with parsing incoming message. */
1554
1555 packet_add_padding(64);
1556 packet_send();
1557 return 0;
1558 }
1559
1560 static int
1561 ssh_keysign(struct sshkey *key, u_char **sigp, size_t *lenp,
1562 const u_char *data, size_t datalen)
1563 {
1564 struct sshbuf *b;
1565 struct stat st;
1566 pid_t pid;
1567 int i, r, to[2], from[2], status, sock = packet_get_connection_in();
1568 u_char rversion = 0, version = 2;
1569 void (*osigchld)(int);
1570
1571 *sigp = NULL;
1572 *lenp = 0;
1573
1574 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
1575 error("%s: not installed: %s", __func__, strerror(errno));
1576 return -1;
1577 }
1578 if (fflush(stdout) != 0) {
1579 error("%s: fflush: %s", __func__, strerror(errno));
1580 return -1;
1581 }
1582 if (pipe(to) < 0) {
1583 error("%s: pipe: %s", __func__, strerror(errno));
1584 return -1;
1585 }
1586 if (pipe(from) < 0) {
1587 error("%s: pipe: %s", __func__, strerror(errno));
1588 return -1;
1589 }
1590 if ((pid = fork()) < 0) {
1591 error("%s: fork: %s", __func__, strerror(errno));
1592 return -1;
1593 }
1594 osigchld = signal(SIGCHLD, SIG_DFL);
1595 if (pid == 0) {
1596 /* keep the socket on exec */
1597 fcntl(sock, F_SETFD, 0);
1598 permanently_drop_suid(getuid());
1599 close(from[0]);
1600 if (dup2(from[1], STDOUT_FILENO) < 0)
1601 fatal("%s: dup2: %s", __func__, strerror(errno));
1602 close(to[1]);
1603 if (dup2(to[0], STDIN_FILENO) < 0)
1604 fatal("%s: dup2: %s", __func__, strerror(errno));
1605 close(from[1]);
1606 close(to[0]);
1607 /* Close everything but stdio and the socket */
1608 for (i = STDERR_FILENO + 1; i < sock; i++)
1609 close(i);
1610 closefrom(sock + 1);
1611 debug3("%s: [child] pid=%ld, exec %s",
1612 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN);
1613 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL);
1614 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN,
1615 strerror(errno));
1616 }
1617 close(from[1]);
1618 close(to[0]);
1619
1620 if ((b = sshbuf_new()) == NULL)
1621 fatal("%s: sshbuf_new failed", __func__);
1622 /* send # of sock, data to be signed */
1623 if ((r = sshbuf_put_u32(b, sock)) != 0 ||
1624 (r = sshbuf_put_string(b, data, datalen)) != 0)
1625 fatal("%s: buffer error: %s", __func__, ssh_err(r));
1626 if (ssh_msg_send(to[1], version, b) == -1)
1627 fatal("%s: couldn't send request", __func__);
1628 sshbuf_reset(b);
1629 r = ssh_msg_recv(from[0], b);
1630 close(from[0]);
1631 close(to[1]);
1632 if (r < 0) {
1633 error("%s: no reply", __func__);
1634 goto fail;
1635 }
1636
1637 errno = 0;
1638 while (waitpid(pid, &status, 0) < 0) {
1639 if (errno != EINTR) {
1640 error("%s: waitpid %ld: %s",
1641 __func__, (long)pid, strerror(errno));
1642 goto fail;
1643 }
1644 }
1645 if (!WIFEXITED(status)) {
1646 error("%s: exited abnormally", __func__);
1647 goto fail;
1648 }
1649 if (WEXITSTATUS(status) != 0) {
1650 error("%s: exited with status %d",
1651 __func__, WEXITSTATUS(status));
1652 goto fail;
1653 }
1654 if ((r = sshbuf_get_u8(b, &rversion)) != 0) {
1655 error("%s: buffer error: %s", __func__, ssh_err(r));
1656 goto fail;
1657 }
1658 if (rversion != version) {
1659 error("%s: bad version", __func__);
1660 goto fail;
1661 }
1662 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) {
1663 error("%s: buffer error: %s", __func__, ssh_err(r));
1664 fail:
1665 signal(SIGCHLD, osigchld);
1666 sshbuf_free(b);
1667 return -1;
1668 }
1669 signal(SIGCHLD, osigchld);
1670 sshbuf_free(b);
1671
1672 return 0;
1673 }
1674
1675 int
1676 userauth_hostbased(Authctxt *authctxt)
1677 {
1678 struct ssh *ssh = active_state;
1679 struct sshkey *private = NULL;
1680 struct sshbuf *b = NULL;
1681 const char *service;
1682 u_char *sig = NULL, *keyblob = NULL;
1683 char *fp = NULL, *chost = NULL, *lname = NULL;
1684 size_t siglen = 0, keylen = 0;
1685 int i, r, success = 0;
1686
1687 if (authctxt->ktypes == NULL) {
1688 authctxt->oktypes = xstrdup(options.hostbased_key_types);
1689 authctxt->ktypes = authctxt->oktypes;
1690 }
1691
1692 /*
1693 * Work through each listed type pattern in HostbasedKeyTypes,
1694 * trying each hostkey that matches the type in turn.
1695 */
1696 for (;;) {
1697 if (authctxt->active_ktype == NULL)
1698 authctxt->active_ktype = strsep(&authctxt->ktypes, ",");
1699 if (authctxt->active_ktype == NULL ||
1700 *authctxt->active_ktype == '\0')
1701 break;
1702 debug3("%s: trying key type %s", __func__,
1703 authctxt->active_ktype);
1704
1705 /* check for a useful key */
1706 private = NULL;
1707 for (i = 0; i < authctxt->sensitive->nkeys; i++) {
1708 if (authctxt->sensitive->keys[i] == NULL ||
1709 authctxt->sensitive->keys[i]->type == KEY_RSA1 ||
1710 authctxt->sensitive->keys[i]->type == KEY_UNSPEC)
1711 continue;
1712 if (match_pattern_list(
1713 sshkey_ssh_name(authctxt->sensitive->keys[i]),
1714 authctxt->active_ktype, 0) != 1)
1715 continue;
1716 /* we take and free the key */
1717 private = authctxt->sensitive->keys[i];
1718 authctxt->sensitive->keys[i] = NULL;
1719 break;
1720 }
1721 /* Found one */
1722 if (private != NULL)
1723 break;
1724 /* No more keys of this type; advance */
1725 authctxt->active_ktype = NULL;
1726 }
1727 if (private == NULL) {
1728 free(authctxt->oktypes);
1729 authctxt->oktypes = authctxt->ktypes = NULL;
1730 authctxt->active_ktype = NULL;
1731 debug("No more client hostkeys for hostbased authentication.");
1732 goto out;
1733 }
1734
1735 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash,
1736 SSH_FP_DEFAULT)) == NULL) {
1737 error("%s: sshkey_fingerprint failed", __func__);
1738 goto out;
1739 }
1740 debug("%s: trying hostkey %s %s",
1741 __func__, sshkey_ssh_name(private), fp);
1742
1743 /* figure out a name for the client host */
1744 if ((lname = get_local_name(packet_get_connection_in())) == NULL) {
1745 error("%s: cannot get local ipaddr/name", __func__);
1746 goto out;
1747 }
1748
1749 /* XXX sshbuf_put_stringf? */
1750 xasprintf(&chost, "%s.", lname);
1751 debug2("%s: chost %s", __func__, chost);
1752
1753 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1754 authctxt->service;
1755
1756 /* construct data */
1757 if ((b = sshbuf_new()) == NULL) {
1758 error("%s: sshbuf_new failed", __func__);
1759 goto out;
1760 }
1761 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) {
1762 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r));
1763 goto out;
1764 }
1765 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 ||
1766 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
1767 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 ||
1768 (r = sshbuf_put_cstring(b, service)) != 0 ||
1769 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 ||
1770 (r = sshbuf_put_cstring(b, key_ssh_name(private))) != 0 ||
1771 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 ||
1772 (r = sshbuf_put_cstring(b, chost)) != 0 ||
1773 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) {
1774 error("%s: buffer error: %s", __func__, ssh_err(r));
1775 goto out;
1776 }
1777
1778 #ifdef DEBUG_PK
1779 sshbuf_dump(b, stderr);
1780 #endif
1781 if (authctxt->sensitive->external_keysign)
1782 r = ssh_keysign(private, &sig, &siglen,
1783 sshbuf_ptr(b), sshbuf_len(b));
1784 else if ((r = sshkey_sign(private, &sig, &siglen,
1785 sshbuf_ptr(b), sshbuf_len(b), NULL, datafellows)) != 0)
1786 debug("%s: sshkey_sign: %s", __func__, ssh_err(r));
1787 if (r != 0) {
1788 error("sign using hostkey %s %s failed",
1789 sshkey_ssh_name(private), fp);
1790 goto out;
1791 }
1792 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 ||
1793 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 ||
1794 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 ||
1795 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 ||
1796 (r = sshpkt_put_cstring(ssh, key_ssh_name(private))) != 0 ||
1797 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 ||
1798 (r = sshpkt_put_cstring(ssh, chost)) != 0 ||
1799 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 ||
1800 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 ||
1801 (r = sshpkt_send(ssh)) != 0) {
1802 error("%s: packet error: %s", __func__, ssh_err(r));
1803 goto out;
1804 }
1805 success = 1;
1806
1807 out:
1808 if (sig != NULL) {
1809 explicit_bzero(sig, siglen);
1810 free(sig);
1811 }
1812 free(keyblob);
1813 free(lname);
1814 free(fp);
1815 free(chost);
1816 sshkey_free(private);
1817 sshbuf_free(b);
1818
1819 return success;
1820 }
1821
1822 /* find auth method */
1823
1824 /*
1825 * given auth method name, if configurable options permit this method fill
1826 * in auth_ident field and return true, otherwise return false.
1827 */
1828 static int
1829 authmethod_is_enabled(Authmethod *method)
1830 {
1831 if (method == NULL)
1832 return 0;
1833 /* return false if options indicate this method is disabled */
1834 if (method->enabled == NULL || *method->enabled == 0)
1835 return 0;
1836 /* return false if batch mode is enabled but method needs interactive mode */
1837 if (method->batch_flag != NULL && *method->batch_flag != 0)
1838 return 0;
1839 return 1;
1840 }
1841
1842 static Authmethod *
1843 authmethod_lookup(const char *name)
1844 {
1845 Authmethod *method = NULL;
1846 if (name != NULL)
1847 for (method = authmethods; method->name != NULL; method++)
1848 if (strcmp(name, method->name) == 0)
1849 return method;
1850 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1851 return NULL;
1852 }
1853
1854 /* XXX internal state */
1855 static Authmethod *current = NULL;
1856 static char *supported = NULL;
1857 static char *preferred = NULL;
1858
1859 /*
1860 * Given the authentication method list sent by the server, return the
1861 * next method we should try. If the server initially sends a nil list,
1862 * use a built-in default list.
1863 */
1864 static Authmethod *
1865 authmethod_get(char *authlist)
1866 {
1867 char *name = NULL;
1868 u_int next;
1869
1870 /* Use a suitable default if we're passed a nil list. */
1871 if (authlist == NULL || strlen(authlist) == 0)
1872 authlist = options.preferred_authentications;
1873
1874 if (supported == NULL || strcmp(authlist, supported) != 0) {
1875 debug3("start over, passed a different list %s", authlist);
1876 free(supported);
1877 supported = xstrdup(authlist);
1878 preferred = options.preferred_authentications;
1879 debug3("preferred %s", preferred);
1880 current = NULL;
1881 } else if (current != NULL && authmethod_is_enabled(current))
1882 return current;
1883
1884 for (;;) {
1885 if ((name = match_list(preferred, supported, &next)) == NULL) {
1886 debug("No more authentication methods to try.");
1887 current = NULL;
1888 return NULL;
1889 }
1890 preferred += next;
1891 debug3("authmethod_lookup %s", name);
1892 debug3("remaining preferred: %s", preferred);
1893 if ((current = authmethod_lookup(name)) != NULL &&
1894 authmethod_is_enabled(current)) {
1895 debug3("authmethod_is_enabled %s", name);
1896 debug("Next authentication method: %s", name);
1897 free(name);
1898 return current;
1899 }
1900 free(name);
1901 }
1902 }
1903
1904 static char *
1905 authmethods_get(void)
1906 {
1907 Authmethod *method = NULL;
1908 Buffer b;
1909 char *list;
1910
1911 buffer_init(&b);
1912 for (method = authmethods; method->name != NULL; method++) {
1913 if (authmethod_is_enabled(method)) {
1914 if (buffer_len(&b) > 0)
1915 buffer_append(&b, ",", 1);
1916 buffer_append(&b, method->name, strlen(method->name));
1917 }
1918 }
1919 if ((list = sshbuf_dup_string(&b)) == NULL)
1920 fatal("%s: sshbuf_dup_string failed", __func__);
1921 buffer_free(&b);
1922 return list;
1923 }
1924
DragonFly BSD