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Import of OpenSSH 3.3p1
[gssapi-openssh.git] / openssh / sshconnect2.c
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3c0ef626 1/*
2 * Copyright (c) 2000 Markus Friedl. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
f5799ae1 26RCSID("$OpenBSD: sshconnect2.c,v 1.104 2002/06/19 00:27:55 deraadt Exp $");
3c0ef626 27
28#include "ssh.h"
29#include "ssh2.h"
30#include "xmalloc.h"
3c0ef626 31#include "buffer.h"
32#include "packet.h"
3c0ef626 33#include "compat.h"
34#include "bufaux.h"
35#include "cipher.h"
36#include "kex.h"
37#include "myproposal.h"
3c0ef626 38#include "sshconnect.h"
39#include "authfile.h"
40#include "dh.h"
41#include "authfd.h"
42#include "log.h"
43#include "readconf.h"
44#include "readpass.h"
45#include "match.h"
46#include "dispatch.h"
47#include "canohost.h"
f5799ae1 48#include "msg.h"
49#include "pathnames.h"
3c0ef626 50
51/* import */
52extern char *client_version_string;
53extern char *server_version_string;
54extern Options options;
55
56/*
57 * SSH2 key exchange
58 */
59
60u_char *session_id2 = NULL;
61int session_id2_len = 0;
62
63char *xxx_host;
64struct sockaddr *xxx_hostaddr;
65
66Kex *xxx_kex = NULL;
67
68static int
69verify_host_key_callback(Key *hostkey)
70{
71 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
72 fatal("Host key verification failed.");
73 return 0;
74}
75
76void
77ssh_kex2(char *host, struct sockaddr *hostaddr)
78{
79 Kex *kex;
80
81 xxx_host = host;
82 xxx_hostaddr = hostaddr;
83
84 if (options.ciphers == (char *)-1) {
85 log("No valid ciphers for protocol version 2 given, using defaults.");
86 options.ciphers = NULL;
87 }
88 if (options.ciphers != NULL) {
89 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
90 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
91 }
92 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
93 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
94 myproposal[PROPOSAL_ENC_ALGS_STOC] =
95 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
96 if (options.compression) {
97 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
98 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib";
99 } else {
100 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
101 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none";
102 }
103 if (options.macs != NULL) {
104 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
105 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
106 }
107 if (options.hostkeyalgorithms != NULL)
e9a17296 108 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
3c0ef626 109 options.hostkeyalgorithms;
110
111 /* start key exchange */
112 kex = kex_setup(myproposal);
113 kex->client_version_string=client_version_string;
114 kex->server_version_string=server_version_string;
115 kex->verify_host_key=&verify_host_key_callback;
116
117 xxx_kex = kex;
118
119 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
120
121 session_id2 = kex->session_id;
122 session_id2_len = kex->session_id_len;
123
124#ifdef DEBUG_KEXDH
125 /* send 1st encrypted/maced/compressed message */
126 packet_start(SSH2_MSG_IGNORE);
127 packet_put_cstring("markus");
128 packet_send();
129 packet_write_wait();
130#endif
131 debug("done: ssh_kex2.");
132}
133
134/*
135 * Authenticate user
136 */
137
138typedef struct Authctxt Authctxt;
139typedef struct Authmethod Authmethod;
140
141typedef int sign_cb_fn(
142 Authctxt *authctxt, Key *key,
e9a17296 143 u_char **sigp, u_int *lenp, u_char *data, u_int datalen);
3c0ef626 144
145struct Authctxt {
146 const char *server_user;
147 const char *local_user;
148 const char *host;
149 const char *service;
150 Authmethod *method;
151 int success;
152 char *authlist;
153 /* pubkey */
154 Key *last_key;
155 sign_cb_fn *last_key_sign;
156 int last_key_hint;
157 AuthenticationConnection *agent;
158 /* hostbased */
f5799ae1 159 Sensitive *sensitive;
3c0ef626 160 /* kbd-interactive */
161 int info_req_seen;
162};
163struct Authmethod {
164 char *name; /* string to compare against server's list */
165 int (*userauth)(Authctxt *authctxt);
166 int *enabled; /* flag in option struct that enables method */
167 int *batch_flag; /* flag in option struct that disables method */
168};
169
e9a17296 170void input_userauth_success(int, u_int32_t, void *);
171void input_userauth_failure(int, u_int32_t, void *);
172void input_userauth_banner(int, u_int32_t, void *);
173void input_userauth_error(int, u_int32_t, void *);
174void input_userauth_info_req(int, u_int32_t, void *);
175void input_userauth_pk_ok(int, u_int32_t, void *);
700318f3 176void input_userauth_passwd_changereq(int, u_int32_t, void *);
3c0ef626 177
e9a17296 178int userauth_none(Authctxt *);
179int userauth_pubkey(Authctxt *);
180int userauth_passwd(Authctxt *);
181int userauth_kbdint(Authctxt *);
182int userauth_hostbased(Authctxt *);
3c0ef626 183
e9a17296 184void userauth(Authctxt *, char *);
3c0ef626 185
186static int sign_and_send_pubkey(Authctxt *, Key *, sign_cb_fn *);
187static void clear_auth_state(Authctxt *);
188
189static Authmethod *authmethod_get(char *authlist);
190static Authmethod *authmethod_lookup(const char *name);
191static char *authmethods_get(void);
192
193Authmethod authmethods[] = {
194 {"hostbased",
195 userauth_hostbased,
196 &options.hostbased_authentication,
197 NULL},
198 {"publickey",
199 userauth_pubkey,
200 &options.pubkey_authentication,
201 NULL},
202 {"keyboard-interactive",
203 userauth_kbdint,
204 &options.kbd_interactive_authentication,
205 &options.batch_mode},
206 {"password",
207 userauth_passwd,
208 &options.password_authentication,
209 &options.batch_mode},
210 {"none",
211 userauth_none,
212 NULL,
213 NULL},
214 {NULL, NULL, NULL, NULL}
215};
216
217void
218ssh_userauth2(const char *local_user, const char *server_user, char *host,
f5799ae1 219 Sensitive *sensitive)
3c0ef626 220{
221 Authctxt authctxt;
222 int type;
3c0ef626 223
224 if (options.challenge_response_authentication)
225 options.kbd_interactive_authentication = 1;
226
227 debug("send SSH2_MSG_SERVICE_REQUEST");
228 packet_start(SSH2_MSG_SERVICE_REQUEST);
229 packet_put_cstring("ssh-userauth");
230 packet_send();
231 packet_write_wait();
e9a17296 232 type = packet_read();
3c0ef626 233 if (type != SSH2_MSG_SERVICE_ACCEPT) {
234 fatal("denied SSH2_MSG_SERVICE_ACCEPT: %d", type);
235 }
236 if (packet_remaining() > 0) {
e9a17296 237 char *reply = packet_get_string(NULL);
3c0ef626 238 debug("service_accept: %s", reply);
239 xfree(reply);
240 } else {
241 debug("buggy server: service_accept w/o service");
242 }
e9a17296 243 packet_check_eom();
3c0ef626 244 debug("got SSH2_MSG_SERVICE_ACCEPT");
245
246 if (options.preferred_authentications == NULL)
247 options.preferred_authentications = authmethods_get();
248
249 /* setup authentication context */
250 memset(&authctxt, 0, sizeof(authctxt));
251 authctxt.agent = ssh_get_authentication_connection();
252 authctxt.server_user = server_user;
253 authctxt.local_user = local_user;
254 authctxt.host = host;
255 authctxt.service = "ssh-connection"; /* service name */
256 authctxt.success = 0;
257 authctxt.method = authmethod_lookup("none");
258 authctxt.authlist = NULL;
f5799ae1 259 authctxt.sensitive = sensitive;
3c0ef626 260 authctxt.info_req_seen = 0;
261 if (authctxt.method == NULL)
262 fatal("ssh_userauth2: internal error: cannot send userauth none request");
263
264 /* initial userauth request */
265 userauth_none(&authctxt);
266
267 dispatch_init(&input_userauth_error);
268 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
269 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
270 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
271 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
272
273 if (authctxt.agent != NULL)
274 ssh_close_authentication_connection(authctxt.agent);
275
276 debug("ssh-userauth2 successful: method %s", authctxt.method->name);
277}
278void
279userauth(Authctxt *authctxt, char *authlist)
280{
281 if (authlist == NULL) {
282 authlist = authctxt->authlist;
283 } else {
284 if (authctxt->authlist)
285 xfree(authctxt->authlist);
286 authctxt->authlist = authlist;
287 }
288 for (;;) {
289 Authmethod *method = authmethod_get(authlist);
290 if (method == NULL)
291 fatal("Permission denied (%s).", authlist);
292 authctxt->method = method;
293 if (method->userauth(authctxt) != 0) {
294 debug2("we sent a %s packet, wait for reply", method->name);
295 break;
296 } else {
297 debug2("we did not send a packet, disable method");
298 method->enabled = NULL;
299 }
300 }
301}
302void
e9a17296 303input_userauth_error(int type, u_int32_t seq, void *ctxt)
3c0ef626 304{
305 fatal("input_userauth_error: bad message during authentication: "
306 "type %d", type);
307}
308void
e9a17296 309input_userauth_banner(int type, u_int32_t seq, void *ctxt)
3c0ef626 310{
311 char *msg, *lang;
312 debug3("input_userauth_banner");
313 msg = packet_get_string(NULL);
314 lang = packet_get_string(NULL);
315 fprintf(stderr, "%s", msg);
316 xfree(msg);
317 xfree(lang);
318}
319void
e9a17296 320input_userauth_success(int type, u_int32_t seq, void *ctxt)
3c0ef626 321{
322 Authctxt *authctxt = ctxt;
323 if (authctxt == NULL)
324 fatal("input_userauth_success: no authentication context");
325 if (authctxt->authlist)
326 xfree(authctxt->authlist);
327 clear_auth_state(authctxt);
328 authctxt->success = 1; /* break out */
329}
330void
e9a17296 331input_userauth_failure(int type, u_int32_t seq, void *ctxt)
3c0ef626 332{
333 Authctxt *authctxt = ctxt;
334 char *authlist = NULL;
335 int partial;
336
337 if (authctxt == NULL)
338 fatal("input_userauth_failure: no authentication context");
339
340 authlist = packet_get_string(NULL);
341 partial = packet_get_char();
e9a17296 342 packet_check_eom();
3c0ef626 343
344 if (partial != 0)
345 log("Authenticated with partial success.");
346 debug("authentications that can continue: %s", authlist);
347
348 clear_auth_state(authctxt);
349 userauth(authctxt, authlist);
350}
351void
e9a17296 352input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
3c0ef626 353{
354 Authctxt *authctxt = ctxt;
355 Key *key = NULL;
356 Buffer b;
e9a17296 357 int pktype, sent = 0;
358 u_int alen, blen;
359 char *pkalg, *fp;
360 u_char *pkblob;
3c0ef626 361
362 if (authctxt == NULL)
363 fatal("input_userauth_pk_ok: no authentication context");
364 if (datafellows & SSH_BUG_PKOK) {
365 /* this is similar to SSH_BUG_PKAUTH */
366 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
367 pkblob = packet_get_string(&blen);
368 buffer_init(&b);
369 buffer_append(&b, pkblob, blen);
370 pkalg = buffer_get_string(&b, &alen);
371 buffer_free(&b);
372 } else {
373 pkalg = packet_get_string(&alen);
374 pkblob = packet_get_string(&blen);
375 }
e9a17296 376 packet_check_eom();
3c0ef626 377
378 debug("input_userauth_pk_ok: pkalg %s blen %d lastkey %p hint %d",
379 pkalg, blen, authctxt->last_key, authctxt->last_key_hint);
380
381 do {
382 if (authctxt->last_key == NULL ||
383 authctxt->last_key_sign == NULL) {
384 debug("no last key or no sign cb");
385 break;
386 }
e9a17296 387 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
3c0ef626 388 debug("unknown pkalg %s", pkalg);
389 break;
390 }
391 if ((key = key_from_blob(pkblob, blen)) == NULL) {
392 debug("no key from blob. pkalg %s", pkalg);
393 break;
394 }
700318f3 395 if (key->type != pktype) {
e9a17296 396 error("input_userauth_pk_ok: type mismatch "
397 "for decoded key (received %d, expected %d)",
f5799ae1 398 key->type, pktype);
e9a17296 399 break;
400 }
3c0ef626 401 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
402 debug2("input_userauth_pk_ok: fp %s", fp);
403 xfree(fp);
404 if (!key_equal(key, authctxt->last_key)) {
405 debug("key != last_key");
406 break;
407 }
408 sent = sign_and_send_pubkey(authctxt, key,
409 authctxt->last_key_sign);
e9a17296 410 } while (0);
3c0ef626 411
412 if (key != NULL)
413 key_free(key);
414 xfree(pkalg);
415 xfree(pkblob);
416
417 /* unregister */
418 clear_auth_state(authctxt);
419 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, NULL);
420
421 /* try another method if we did not send a packet*/
422 if (sent == 0)
423 userauth(authctxt, NULL);
424
425}
426
427int
428userauth_none(Authctxt *authctxt)
429{
430 /* initial userauth request */
431 packet_start(SSH2_MSG_USERAUTH_REQUEST);
432 packet_put_cstring(authctxt->server_user);
433 packet_put_cstring(authctxt->service);
434 packet_put_cstring(authctxt->method->name);
435 packet_send();
436 return 1;
437}
438
439int
440userauth_passwd(Authctxt *authctxt)
441{
442 static int attempt = 0;
700318f3 443 char prompt[150];
3c0ef626 444 char *password;
445
446 if (attempt++ >= options.number_of_password_prompts)
447 return 0;
448
e9a17296 449 if (attempt != 1)
3c0ef626 450 error("Permission denied, please try again.");
451
452 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
453 authctxt->server_user, authctxt->host);
454 password = read_passphrase(prompt, 0);
455 packet_start(SSH2_MSG_USERAUTH_REQUEST);
456 packet_put_cstring(authctxt->server_user);
457 packet_put_cstring(authctxt->service);
458 packet_put_cstring(authctxt->method->name);
459 packet_put_char(0);
460 packet_put_cstring(password);
461 memset(password, 0, strlen(password));
462 xfree(password);
463 packet_add_padding(64);
464 packet_send();
700318f3 465
f5799ae1 466 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
700318f3 467 &input_userauth_passwd_changereq);
468
3c0ef626 469 return 1;
470}
700318f3 471/*
472 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
473 */
474void
475input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
476{
477 Authctxt *authctxt = ctxt;
478 char *info, *lang, *password = NULL, *retype = NULL;
479 char prompt[150];
480
481 debug2("input_userauth_passwd_changereq");
482
483 if (authctxt == NULL)
484 fatal("input_userauth_passwd_changereq: "
485 "no authentication context");
486
487 info = packet_get_string(NULL);
488 lang = packet_get_string(NULL);
489 if (strlen(info) > 0)
490 log("%s", info);
491 xfree(info);
492 xfree(lang);
493 packet_start(SSH2_MSG_USERAUTH_REQUEST);
494 packet_put_cstring(authctxt->server_user);
495 packet_put_cstring(authctxt->service);
496 packet_put_cstring(authctxt->method->name);
497 packet_put_char(1); /* additional info */
f5799ae1 498 snprintf(prompt, sizeof(prompt),
700318f3 499 "Enter %.30s@%.128s's old password: ",
500 authctxt->server_user, authctxt->host);
501 password = read_passphrase(prompt, 0);
502 packet_put_cstring(password);
503 memset(password, 0, strlen(password));
504 xfree(password);
505 password = NULL;
506 while (password == NULL) {
f5799ae1 507 snprintf(prompt, sizeof(prompt),
700318f3 508 "Enter %.30s@%.128s's new password: ",
509 authctxt->server_user, authctxt->host);
510 password = read_passphrase(prompt, RP_ALLOW_EOF);
511 if (password == NULL) {
512 /* bail out */
513 return;
514 }
f5799ae1 515 snprintf(prompt, sizeof(prompt),
700318f3 516 "Retype %.30s@%.128s's new password: ",
517 authctxt->server_user, authctxt->host);
518 retype = read_passphrase(prompt, 0);
519 if (strcmp(password, retype) != 0) {
520 memset(password, 0, strlen(password));
521 xfree(password);
522 log("Mismatch; try again, EOF to quit.");
523 password = NULL;
524 }
525 memset(retype, 0, strlen(retype));
526 xfree(retype);
527 }
528 packet_put_cstring(password);
529 memset(password, 0, strlen(password));
530 xfree(password);
531 packet_add_padding(64);
532 packet_send();
f5799ae1 533
534 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
700318f3 535 &input_userauth_passwd_changereq);
536}
3c0ef626 537
538static void
539clear_auth_state(Authctxt *authctxt)
540{
541 /* XXX clear authentication state */
700318f3 542 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, NULL);
543
3c0ef626 544 if (authctxt->last_key != NULL && authctxt->last_key_hint == -1) {
545 debug3("clear_auth_state: key_free %p", authctxt->last_key);
546 key_free(authctxt->last_key);
547 }
548 authctxt->last_key = NULL;
549 authctxt->last_key_hint = -2;
550 authctxt->last_key_sign = NULL;
551}
552
553static int
554sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
555{
556 Buffer b;
557 u_char *blob, *signature;
e9a17296 558 u_int bloblen, slen;
3c0ef626 559 int skip = 0;
560 int ret = -1;
561 int have_sig = 1;
562
563 debug3("sign_and_send_pubkey");
564
565 if (key_to_blob(k, &blob, &bloblen) == 0) {
566 /* we cannot handle this key */
567 debug3("sign_and_send_pubkey: cannot handle key");
568 return 0;
569 }
570 /* data to be signed */
571 buffer_init(&b);
572 if (datafellows & SSH_OLD_SESSIONID) {
573 buffer_append(&b, session_id2, session_id2_len);
574 skip = session_id2_len;
575 } else {
576 buffer_put_string(&b, session_id2, session_id2_len);
577 skip = buffer_len(&b);
578 }
579 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
580 buffer_put_cstring(&b, authctxt->server_user);
581 buffer_put_cstring(&b,
582 datafellows & SSH_BUG_PKSERVICE ?
583 "ssh-userauth" :
584 authctxt->service);
585 if (datafellows & SSH_BUG_PKAUTH) {
586 buffer_put_char(&b, have_sig);
587 } else {
588 buffer_put_cstring(&b, authctxt->method->name);
589 buffer_put_char(&b, have_sig);
590 buffer_put_cstring(&b, key_ssh_name(k));
591 }
592 buffer_put_string(&b, blob, bloblen);
593
594 /* generate signature */
595 ret = (*sign_callback)(authctxt, k, &signature, &slen,
596 buffer_ptr(&b), buffer_len(&b));
597 if (ret == -1) {
598 xfree(blob);
599 buffer_free(&b);
600 return 0;
601 }
602#ifdef DEBUG_PK
603 buffer_dump(&b);
604#endif
605 if (datafellows & SSH_BUG_PKSERVICE) {
606 buffer_clear(&b);
607 buffer_append(&b, session_id2, session_id2_len);
608 skip = session_id2_len;
609 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
610 buffer_put_cstring(&b, authctxt->server_user);
611 buffer_put_cstring(&b, authctxt->service);
612 buffer_put_cstring(&b, authctxt->method->name);
613 buffer_put_char(&b, have_sig);
614 if (!(datafellows & SSH_BUG_PKAUTH))
615 buffer_put_cstring(&b, key_ssh_name(k));
616 buffer_put_string(&b, blob, bloblen);
617 }
618 xfree(blob);
619
620 /* append signature */
621 buffer_put_string(&b, signature, slen);
622 xfree(signature);
623
624 /* skip session id and packet type */
625 if (buffer_len(&b) < skip + 1)
626 fatal("userauth_pubkey: internal error");
627 buffer_consume(&b, skip + 1);
628
629 /* put remaining data from buffer into packet */
630 packet_start(SSH2_MSG_USERAUTH_REQUEST);
631 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
632 buffer_free(&b);
633 packet_send();
634
635 return 1;
636}
637
638static int
639send_pubkey_test(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback,
640 int hint)
641{
642 u_char *blob;
e9a17296 643 u_int bloblen, have_sig = 0;
3c0ef626 644
645 debug3("send_pubkey_test");
646
647 if (key_to_blob(k, &blob, &bloblen) == 0) {
648 /* we cannot handle this key */
649 debug3("send_pubkey_test: cannot handle key");
650 return 0;
651 }
652 /* register callback for USERAUTH_PK_OK message */
653 authctxt->last_key_sign = sign_callback;
654 authctxt->last_key_hint = hint;
655 authctxt->last_key = k;
656 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
657
658 packet_start(SSH2_MSG_USERAUTH_REQUEST);
659 packet_put_cstring(authctxt->server_user);
660 packet_put_cstring(authctxt->service);
661 packet_put_cstring(authctxt->method->name);
662 packet_put_char(have_sig);
663 if (!(datafellows & SSH_BUG_PKAUTH))
664 packet_put_cstring(key_ssh_name(k));
665 packet_put_string(blob, bloblen);
666 xfree(blob);
667 packet_send();
668 return 1;
669}
670
671static Key *
672load_identity_file(char *filename)
673{
674 Key *private;
675 char prompt[300], *passphrase;
676 int quit, i;
677 struct stat st;
678
679 if (stat(filename, &st) < 0) {
680 debug3("no such identity: %s", filename);
681 return NULL;
682 }
683 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL);
684 if (private == NULL) {
685 if (options.batch_mode)
686 return NULL;
687 snprintf(prompt, sizeof prompt,
e9a17296 688 "Enter passphrase for key '%.100s': ", filename);
3c0ef626 689 for (i = 0; i < options.number_of_password_prompts; i++) {
690 passphrase = read_passphrase(prompt, 0);
691 if (strcmp(passphrase, "") != 0) {
692 private = key_load_private_type(KEY_UNSPEC, filename,
693 passphrase, NULL);
694 quit = 0;
695 } else {
696 debug2("no passphrase given, try next key");
697 quit = 1;
698 }
699 memset(passphrase, 0, strlen(passphrase));
700 xfree(passphrase);
701 if (private != NULL || quit)
702 break;
703 debug2("bad passphrase given, try again...");
704 }
705 }
706 return private;
707}
708
709static int
e9a17296 710identity_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
711 u_char *data, u_int datalen)
3c0ef626 712{
713 Key *private;
714 int idx, ret;
715
716 idx = authctxt->last_key_hint;
717 if (idx < 0)
718 return -1;
719
720 /* private key is stored in external hardware */
e9a17296 721 if (options.identity_keys[idx]->flags & KEY_FLAG_EXT)
3c0ef626 722 return key_sign(options.identity_keys[idx], sigp, lenp, data, datalen);
723
724 private = load_identity_file(options.identity_files[idx]);
725 if (private == NULL)
726 return -1;
727 ret = key_sign(private, sigp, lenp, data, datalen);
728 key_free(private);
729 return ret;
730}
731
732static int
e9a17296 733agent_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
734 u_char *data, u_int datalen)
3c0ef626 735{
736 return ssh_agent_sign(authctxt->agent, key, sigp, lenp, data, datalen);
737}
738
739static int
e9a17296 740key_sign_cb(Authctxt *authctxt, Key *key, u_char **sigp, u_int *lenp,
741 u_char *data, u_int datalen)
3c0ef626 742{
743 return key_sign(key, sigp, lenp, data, datalen);
744}
745
746static int
747userauth_pubkey_agent(Authctxt *authctxt)
748{
749 static int called = 0;
750 int ret = 0;
751 char *comment;
752 Key *k;
753
754 if (called == 0) {
755 if (ssh_get_num_identities(authctxt->agent, 2) == 0)
756 debug2("userauth_pubkey_agent: no keys at all");
757 called = 1;
758 }
759 k = ssh_get_next_identity(authctxt->agent, &comment, 2);
760 if (k == NULL) {
761 debug2("userauth_pubkey_agent: no more keys");
762 } else {
763 debug("userauth_pubkey_agent: testing agent key %s", comment);
764 xfree(comment);
765 ret = send_pubkey_test(authctxt, k, agent_sign_cb, -1);
766 if (ret == 0)
767 key_free(k);
768 }
769 if (ret == 0)
770 debug2("userauth_pubkey_agent: no message sent");
771 return ret;
772}
773
774int
775userauth_pubkey(Authctxt *authctxt)
776{
777 static int idx = 0;
778 int sent = 0;
779 Key *key;
780 char *filename;
781
782 if (authctxt->agent != NULL) {
783 do {
784 sent = userauth_pubkey_agent(authctxt);
e9a17296 785 } while (!sent && authctxt->agent->howmany > 0);
3c0ef626 786 }
787 while (!sent && idx < options.num_identity_files) {
788 key = options.identity_keys[idx];
789 filename = options.identity_files[idx];
790 if (key == NULL) {
791 debug("try privkey: %s", filename);
792 key = load_identity_file(filename);
793 if (key != NULL) {
794 sent = sign_and_send_pubkey(authctxt, key,
795 key_sign_cb);
796 key_free(key);
797 }
798 } else if (key->type != KEY_RSA1) {
799 debug("try pubkey: %s", filename);
800 sent = send_pubkey_test(authctxt, key,
801 identity_sign_cb, idx);
802 }
803 idx++;
804 }
805 return sent;
806}
807
808/*
809 * Send userauth request message specifying keyboard-interactive method.
810 */
811int
812userauth_kbdint(Authctxt *authctxt)
813{
814 static int attempt = 0;
815
816 if (attempt++ >= options.number_of_password_prompts)
817 return 0;
818 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
819 if (attempt > 1 && !authctxt->info_req_seen) {
820 debug3("userauth_kbdint: disable: no info_req_seen");
821 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
822 return 0;
823 }
824
825 debug2("userauth_kbdint");
826 packet_start(SSH2_MSG_USERAUTH_REQUEST);
827 packet_put_cstring(authctxt->server_user);
828 packet_put_cstring(authctxt->service);
829 packet_put_cstring(authctxt->method->name);
830 packet_put_cstring(""); /* lang */
831 packet_put_cstring(options.kbd_interactive_devices ?
832 options.kbd_interactive_devices : "");
833 packet_send();
834
835 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
836 return 1;
837}
838
839/*
840 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
841 */
842void
e9a17296 843input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
3c0ef626 844{
845 Authctxt *authctxt = ctxt;
846 char *name, *inst, *lang, *prompt, *response;
847 u_int num_prompts, i;
848 int echo = 0;
849
850 debug2("input_userauth_info_req");
851
852 if (authctxt == NULL)
853 fatal("input_userauth_info_req: no authentication context");
854
855 authctxt->info_req_seen = 1;
856
857 name = packet_get_string(NULL);
858 inst = packet_get_string(NULL);
859 lang = packet_get_string(NULL);
860 if (strlen(name) > 0)
861 log("%s", name);
862 if (strlen(inst) > 0)
863 log("%s", inst);
864 xfree(name);
865 xfree(inst);
866 xfree(lang);
867
868 num_prompts = packet_get_int();
869 /*
870 * Begin to build info response packet based on prompts requested.
871 * We commit to providing the correct number of responses, so if
872 * further on we run into a problem that prevents this, we have to
873 * be sure and clean this up and send a correct error response.
874 */
875 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
876 packet_put_int(num_prompts);
877
878 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
879 for (i = 0; i < num_prompts; i++) {
880 prompt = packet_get_string(NULL);
881 echo = packet_get_char();
882
883 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
884
885 packet_put_cstring(response);
886 memset(response, 0, strlen(response));
887 xfree(response);
888 xfree(prompt);
889 }
e9a17296 890 packet_check_eom(); /* done with parsing incoming message. */
3c0ef626 891
892 packet_add_padding(64);
893 packet_send();
894}
895
f5799ae1 896static int
897ssh_keysign(
898 Key *key,
899 u_char **sigp, u_int *lenp,
900 u_char *data, u_int datalen)
901{
902 Buffer b;
903 struct stat st;
904 pid_t pid;
905 int to[2], from[2], status, version = 2;
906
907 debug("ssh_keysign called");
908
909 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
910 error("ssh_keysign: no installed: %s", strerror(errno));
911 return -1;
912 }
913 if (fflush(stdout) != 0)
914 error("ssh_keysign: fflush: %s", strerror(errno));
915 if (pipe(to) < 0) {
916 error("ssh_keysign: pipe: %s", strerror(errno));
917 return -1;
918 }
919 if (pipe(from) < 0) {
920 error("ssh_keysign: pipe: %s", strerror(errno));
921 return -1;
922 }
923 if ((pid = fork()) < 0) {
924 error("ssh_keysign: fork: %s", strerror(errno));
925 return -1;
926 }
927 if (pid == 0) {
928 seteuid(getuid());
929 setuid(getuid());
930 close(from[0]);
931 if (dup2(from[1], STDOUT_FILENO) < 0)
932 fatal("ssh_keysign: dup2: %s", strerror(errno));
933 close(to[1]);
934 if (dup2(to[0], STDIN_FILENO) < 0)
935 fatal("ssh_keysign: dup2: %s", strerror(errno));
936 close(from[1]);
937 close(to[0]);
938 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
939 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
940 strerror(errno));
941 }
942 close(from[1]);
943 close(to[0]);
944
945 buffer_init(&b);
946 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
947 buffer_put_string(&b, data, datalen);
948 msg_send(to[1], version, &b);
949
950 if (msg_recv(from[0], &b) < 0) {
951 error("ssh_keysign: no reply");
952 buffer_clear(&b);
953 return -1;
954 }
955 close(from[0]);
956 close(to[1]);
957
958 while (waitpid(pid, &status, 0) < 0)
959 if (errno != EINTR)
960 break;
961
962 if (buffer_get_char(&b) != version) {
963 error("ssh_keysign: bad version");
964 buffer_clear(&b);
965 return -1;
966 }
967 *sigp = buffer_get_string(&b, lenp);
968 buffer_clear(&b);
969
970 return 0;
971}
972
3c0ef626 973int
974userauth_hostbased(Authctxt *authctxt)
975{
976 Key *private = NULL;
f5799ae1 977 Sensitive *sensitive = authctxt->sensitive;
3c0ef626 978 Buffer b;
979 u_char *signature, *blob;
980 char *chost, *pkalg, *p;
981 const char *service;
982 u_int blen, slen;
983 int ok, i, len, found = 0;
984
985 /* check for a useful key */
f5799ae1 986 for (i = 0; i < sensitive->nkeys; i++) {
987 private = sensitive->keys[i];
3c0ef626 988 if (private && private->type != KEY_RSA1) {
989 found = 1;
990 /* we take and free the key */
f5799ae1 991 sensitive->keys[i] = NULL;
3c0ef626 992 break;
993 }
994 }
995 if (!found) {
996 debug("userauth_hostbased: no more client hostkeys");
997 return 0;
998 }
999 if (key_to_blob(private, &blob, &blen) == 0) {
1000 key_free(private);
1001 return 0;
1002 }
1003 /* figure out a name for the client host */
1004 p = get_local_name(packet_get_connection_in());
1005 if (p == NULL) {
1006 error("userauth_hostbased: cannot get local ipaddr/name");
1007 key_free(private);
1008 return 0;
1009 }
1010 len = strlen(p) + 2;
1011 chost = xmalloc(len);
1012 strlcpy(chost, p, len);
1013 strlcat(chost, ".", len);
1014 debug2("userauth_hostbased: chost %s", chost);
1015
1016 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1017 authctxt->service;
1018 pkalg = xstrdup(key_ssh_name(private));
1019 buffer_init(&b);
1020 /* construct data */
1021 buffer_put_string(&b, session_id2, session_id2_len);
1022 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1023 buffer_put_cstring(&b, authctxt->server_user);
1024 buffer_put_cstring(&b, service);
1025 buffer_put_cstring(&b, authctxt->method->name);
1026 buffer_put_cstring(&b, pkalg);
1027 buffer_put_string(&b, blob, blen);
1028 buffer_put_cstring(&b, chost);
1029 buffer_put_cstring(&b, authctxt->local_user);
1030#ifdef DEBUG_PK
1031 buffer_dump(&b);
1032#endif
f5799ae1 1033 if (sensitive->external_keysign)
1034 ok = ssh_keysign(private, &signature, &slen,
1035 buffer_ptr(&b), buffer_len(&b));
1036 else
1037 ok = key_sign(private, &signature, &slen,
1038 buffer_ptr(&b), buffer_len(&b));
3c0ef626 1039 key_free(private);
1040 buffer_free(&b);
1041 if (ok != 0) {
1042 error("key_sign failed");
1043 xfree(chost);
1044 xfree(pkalg);
1045 return 0;
1046 }
1047 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1048 packet_put_cstring(authctxt->server_user);
1049 packet_put_cstring(authctxt->service);
1050 packet_put_cstring(authctxt->method->name);
1051 packet_put_cstring(pkalg);
1052 packet_put_string(blob, blen);
1053 packet_put_cstring(chost);
1054 packet_put_cstring(authctxt->local_user);
1055 packet_put_string(signature, slen);
1056 memset(signature, 's', slen);
1057 xfree(signature);
1058 xfree(chost);
1059 xfree(pkalg);
1060
1061 packet_send();
1062 return 1;
1063}
1064
1065/* find auth method */
1066
1067/*
1068 * given auth method name, if configurable options permit this method fill
1069 * in auth_ident field and return true, otherwise return false.
1070 */
1071static int
1072authmethod_is_enabled(Authmethod *method)
1073{
1074 if (method == NULL)
1075 return 0;
1076 /* return false if options indicate this method is disabled */
1077 if (method->enabled == NULL || *method->enabled == 0)
1078 return 0;
1079 /* return false if batch mode is enabled but method needs interactive mode */
1080 if (method->batch_flag != NULL && *method->batch_flag != 0)
1081 return 0;
1082 return 1;
1083}
1084
1085static Authmethod *
1086authmethod_lookup(const char *name)
1087{
1088 Authmethod *method = NULL;
1089 if (name != NULL)
1090 for (method = authmethods; method->name != NULL; method++)
1091 if (strcmp(name, method->name) == 0)
1092 return method;
1093 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1094 return NULL;
1095}
1096
1097/* XXX internal state */
1098static Authmethod *current = NULL;
1099static char *supported = NULL;
1100static char *preferred = NULL;
1101/*
1102 * Given the authentication method list sent by the server, return the
1103 * next method we should try. If the server initially sends a nil list,
1104 * use a built-in default list.
1105 */
1106static Authmethod *
1107authmethod_get(char *authlist)
1108{
1109
1110 char *name = NULL;
e9a17296 1111 u_int next;
3c0ef626 1112
1113 /* Use a suitable default if we're passed a nil list. */
1114 if (authlist == NULL || strlen(authlist) == 0)
1115 authlist = options.preferred_authentications;
1116
1117 if (supported == NULL || strcmp(authlist, supported) != 0) {
1118 debug3("start over, passed a different list %s", authlist);
1119 if (supported != NULL)
1120 xfree(supported);
1121 supported = xstrdup(authlist);
1122 preferred = options.preferred_authentications;
1123 debug3("preferred %s", preferred);
1124 current = NULL;
1125 } else if (current != NULL && authmethod_is_enabled(current))
1126 return current;
1127
1128 for (;;) {
1129 if ((name = match_list(preferred, supported, &next)) == NULL) {
1130 debug("no more auth methods to try");
1131 current = NULL;
1132 return NULL;
1133 }
1134 preferred += next;
1135 debug3("authmethod_lookup %s", name);
1136 debug3("remaining preferred: %s", preferred);
1137 if ((current = authmethod_lookup(name)) != NULL &&
1138 authmethod_is_enabled(current)) {
1139 debug3("authmethod_is_enabled %s", name);
1140 debug("next auth method to try is %s", name);
1141 return current;
1142 }
1143 }
1144}
1145
3c0ef626 1146static char *
1147authmethods_get(void)
1148{
1149 Authmethod *method = NULL;
e9a17296 1150 Buffer b;
1151 char *list;
3c0ef626 1152
e9a17296 1153 buffer_init(&b);
3c0ef626 1154 for (method = authmethods; method->name != NULL; method++) {
1155 if (authmethod_is_enabled(method)) {
e9a17296 1156 if (buffer_len(&b) > 0)
1157 buffer_append(&b, ",", 1);
1158 buffer_append(&b, method->name, strlen(method->name));
3c0ef626 1159 }
1160 }
e9a17296 1161 buffer_append(&b, "\0", 1);
1162 list = xstrdup(buffer_ptr(&b));
1163 buffer_free(&b);
1164 return list;
3c0ef626 1165}
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