Import OpenSSH-5.9p1.
[dragonfly.git] / crypto / openssh / sshconnect2.c
CommitLineData
1c188a7f 1/* $OpenBSD: sshconnect2.c,v 1.188 2011/05/24 07:15:47 djm Exp $ */
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2/*
3 * Copyright (c) 2000 Markus Friedl. All rights reserved.
cb5eb4f1 4 * Copyright (c) 2008 Damien Miller. All rights reserved.
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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>
856ea928 35#include <fcntl.h>
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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>
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43#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H)
44#include <vis.h>
45#endif
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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 "readconf.h"
65#include "misc.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"
9f304aaf 72#include "hostfile.h"
40c002af 73#include "schnorr.h"
cb5eb4f1 74#include "jpake.h"
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75
76#ifdef GSSAPI
77#include "ssh-gss.h"
78#endif
79
80/* import */
81extern char *client_version_string;
82extern char *server_version_string;
83extern Options options;
84
85/*
86 * SSH2 key exchange
87 */
88
89u_char *session_id2 = NULL;
90u_int session_id2_len = 0;
91
92char *xxx_host;
93struct sockaddr *xxx_hostaddr;
94
95Kex *xxx_kex = NULL;
96
97static int
98verify_host_key_callback(Key *hostkey)
99{
100 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1)
101 fatal("Host key verification failed.");
102 return 0;
103}
104
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105static char *
106order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port)
107{
108 char *oavail, *avail, *first, *last, *alg, *hostname, *ret;
109 size_t maxlen;
110 struct hostkeys *hostkeys;
111 int ktype;
1c188a7f 112 u_int i;
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113
114 /* Find all hostkeys for this hostname */
115 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL);
116 hostkeys = init_hostkeys();
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117 for (i = 0; i < options.num_user_hostfiles; i++)
118 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]);
119 for (i = 0; i < options.num_system_hostfiles; i++)
120 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]);
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121
122 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG);
123 maxlen = strlen(avail) + 1;
124 first = xmalloc(maxlen);
125 last = xmalloc(maxlen);
126 *first = *last = '\0';
127
128#define ALG_APPEND(to, from) \
129 do { \
130 if (*to != '\0') \
131 strlcat(to, ",", maxlen); \
132 strlcat(to, from, maxlen); \
133 } while (0)
134
135 while ((alg = strsep(&avail, ",")) && *alg != '\0') {
136 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC)
137 fatal("%s: unknown alg %s", __func__, alg);
138 if (lookup_key_in_hostkeys_by_type(hostkeys,
139 key_type_plain(ktype), NULL))
140 ALG_APPEND(first, alg);
141 else
142 ALG_APPEND(last, alg);
143 }
144#undef ALG_APPEND
145 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last);
146 if (*first != '\0')
147 debug3("%s: prefer hostkeyalgs: %s", __func__, first);
148
149 xfree(first);
150 xfree(last);
151 xfree(hostname);
152 xfree(oavail);
153 free_hostkeys(hostkeys);
154
155 return ret;
156}
157
16c343f1 158void
9f304aaf 159ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port)
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160{
161 Kex *kex;
162
163 xxx_host = host;
164 xxx_hostaddr = hostaddr;
165
166 if (options.ciphers == (char *)-1) {
167 logit("No valid ciphers for protocol version 2 given, using defaults.");
168 options.ciphers = NULL;
169 }
170 if (options.ciphers != NULL) {
171 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
172 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers;
173 }
174 myproposal[PROPOSAL_ENC_ALGS_CTOS] =
175 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]);
176 myproposal[PROPOSAL_ENC_ALGS_STOC] =
177 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]);
178 if (options.compression) {
179 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
180 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none";
181 } else {
182 myproposal[PROPOSAL_COMP_ALGS_CTOS] =
183 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib";
184 }
185 if (options.macs != NULL) {
186 myproposal[PROPOSAL_MAC_ALGS_CTOS] =
187 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs;
188 }
189 if (options.hostkeyalgorithms != NULL)
190 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
191 options.hostkeyalgorithms;
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192 else {
193 /* Prefer algorithms that we already have keys for */
194 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] =
195 order_hostkeyalgs(host, hostaddr, port);
196 }
197 if (options.kex_algorithms != NULL)
198 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms;
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199
200 if (options.rekey_limit)
201 packet_set_rekey_limit((u_int32_t)options.rekey_limit);
202
203 /* start key exchange */
204 kex = kex_setup(myproposal);
205 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client;
206 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client;
207 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client;
208 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client;
9f304aaf 209 kex->kex[KEX_ECDH_SHA2] = kexecdh_client;
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210 kex->client_version_string=client_version_string;
211 kex->server_version_string=server_version_string;
212 kex->verify_host_key=&verify_host_key_callback;
213
214 xxx_kex = kex;
215
216 dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
217
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218 if (options.use_roaming && !kex->roaming) {
219 debug("Roaming not allowed by server");
220 options.use_roaming = 0;
221 }
222
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223 session_id2 = kex->session_id;
224 session_id2_len = kex->session_id_len;
225
226#ifdef DEBUG_KEXDH
227 /* send 1st encrypted/maced/compressed message */
228 packet_start(SSH2_MSG_IGNORE);
229 packet_put_cstring("markus");
230 packet_send();
231 packet_write_wait();
232#endif
233}
234
235/*
236 * Authenticate user
237 */
238
239typedef struct Authctxt Authctxt;
240typedef struct Authmethod Authmethod;
241typedef struct identity Identity;
242typedef struct idlist Idlist;
243
244struct identity {
245 TAILQ_ENTRY(identity) next;
246 AuthenticationConnection *ac; /* set if agent supports key */
247 Key *key; /* public/private key */
248 char *filename; /* comment for agent-only keys */
249 int tried;
250 int isprivate; /* key points to the private key */
251};
252TAILQ_HEAD(idlist, identity);
253
254struct Authctxt {
255 const char *server_user;
256 const char *local_user;
257 const char *host;
258 const char *service;
259 Authmethod *method;
856ea928 260 sig_atomic_t success;
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261 char *authlist;
262 /* pubkey */
263 Idlist keys;
264 AuthenticationConnection *agent;
265 /* hostbased */
266 Sensitive *sensitive;
267 /* kbd-interactive */
268 int info_req_seen;
269 /* generic */
270 void *methoddata;
271};
272struct Authmethod {
273 char *name; /* string to compare against server's list */
274 int (*userauth)(Authctxt *authctxt);
cb5eb4f1 275 void (*cleanup)(Authctxt *authctxt);
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276 int *enabled; /* flag in option struct that enables method */
277 int *batch_flag; /* flag in option struct that disables method */
278};
279
280void input_userauth_success(int, u_int32_t, void *);
856ea928 281void input_userauth_success_unexpected(int, u_int32_t, void *);
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282void input_userauth_failure(int, u_int32_t, void *);
283void input_userauth_banner(int, u_int32_t, void *);
284void input_userauth_error(int, u_int32_t, void *);
285void input_userauth_info_req(int, u_int32_t, void *);
286void input_userauth_pk_ok(int, u_int32_t, void *);
287void input_userauth_passwd_changereq(int, u_int32_t, void *);
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288void input_userauth_jpake_server_step1(int, u_int32_t, void *);
289void input_userauth_jpake_server_step2(int, u_int32_t, void *);
290void input_userauth_jpake_server_confirm(int, u_int32_t, void *);
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291
292int userauth_none(Authctxt *);
293int userauth_pubkey(Authctxt *);
294int userauth_passwd(Authctxt *);
295int userauth_kbdint(Authctxt *);
296int userauth_hostbased(Authctxt *);
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297int userauth_jpake(Authctxt *);
298
299void userauth_jpake_cleanup(Authctxt *);
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300
301#ifdef GSSAPI
302int userauth_gssapi(Authctxt *authctxt);
303void input_gssapi_response(int type, u_int32_t, void *);
304void input_gssapi_token(int type, u_int32_t, void *);
305void input_gssapi_hash(int type, u_int32_t, void *);
306void input_gssapi_error(int, u_int32_t, void *);
307void input_gssapi_errtok(int, u_int32_t, void *);
308#endif
309
310void userauth(Authctxt *, char *);
311
312static int sign_and_send_pubkey(Authctxt *, Identity *);
313static void pubkey_prepare(Authctxt *);
314static void pubkey_cleanup(Authctxt *);
315static Key *load_identity_file(char *);
316
317static Authmethod *authmethod_get(char *authlist);
318static Authmethod *authmethod_lookup(const char *name);
319static char *authmethods_get(void);
320
321Authmethod authmethods[] = {
322#ifdef GSSAPI
323 {"gssapi-with-mic",
324 userauth_gssapi,
cb5eb4f1 325 NULL,
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326 &options.gss_authentication,
327 NULL},
328#endif
329 {"hostbased",
330 userauth_hostbased,
cb5eb4f1 331 NULL,
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332 &options.hostbased_authentication,
333 NULL},
334 {"publickey",
335 userauth_pubkey,
cb5eb4f1 336 NULL,
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337 &options.pubkey_authentication,
338 NULL},
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339#ifdef JPAKE
340 {"jpake-01@openssh.com",
341 userauth_jpake,
342 userauth_jpake_cleanup,
343 &options.zero_knowledge_password_authentication,
344 &options.batch_mode},
345#endif
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346 {"keyboard-interactive",
347 userauth_kbdint,
cb5eb4f1 348 NULL,
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349 &options.kbd_interactive_authentication,
350 &options.batch_mode},
351 {"password",
352 userauth_passwd,
cb5eb4f1 353 NULL,
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354 &options.password_authentication,
355 &options.batch_mode},
356 {"none",
357 userauth_none,
358 NULL,
cb5eb4f1 359 NULL,
16c343f1 360 NULL},
cb5eb4f1 361 {NULL, NULL, NULL, NULL, NULL}
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PA
362};
363
364void
365ssh_userauth2(const char *local_user, const char *server_user, char *host,
366 Sensitive *sensitive)
367{
368 Authctxt authctxt;
369 int type;
370
371 if (options.challenge_response_authentication)
372 options.kbd_interactive_authentication = 1;
373
374 packet_start(SSH2_MSG_SERVICE_REQUEST);
375 packet_put_cstring("ssh-userauth");
376 packet_send();
377 debug("SSH2_MSG_SERVICE_REQUEST sent");
378 packet_write_wait();
379 type = packet_read();
380 if (type != SSH2_MSG_SERVICE_ACCEPT)
381 fatal("Server denied authentication request: %d", type);
382 if (packet_remaining() > 0) {
383 char *reply = packet_get_string(NULL);
384 debug2("service_accept: %s", reply);
385 xfree(reply);
386 } else {
387 debug2("buggy server: service_accept w/o service");
388 }
389 packet_check_eom();
390 debug("SSH2_MSG_SERVICE_ACCEPT received");
391
392 if (options.preferred_authentications == NULL)
393 options.preferred_authentications = authmethods_get();
394
395 /* setup authentication context */
396 memset(&authctxt, 0, sizeof(authctxt));
397 pubkey_prepare(&authctxt);
398 authctxt.server_user = server_user;
399 authctxt.local_user = local_user;
400 authctxt.host = host;
401 authctxt.service = "ssh-connection"; /* service name */
402 authctxt.success = 0;
403 authctxt.method = authmethod_lookup("none");
404 authctxt.authlist = NULL;
405 authctxt.methoddata = NULL;
406 authctxt.sensitive = sensitive;
407 authctxt.info_req_seen = 0;
408 if (authctxt.method == NULL)
409 fatal("ssh_userauth2: internal error: cannot send userauth none request");
410
411 /* initial userauth request */
412 userauth_none(&authctxt);
413
414 dispatch_init(&input_userauth_error);
415 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
416 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure);
417 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner);
418 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */
419
420 pubkey_cleanup(&authctxt);
421 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL);
422
423 debug("Authentication succeeded (%s).", authctxt.method->name);
424}
425
426void
427userauth(Authctxt *authctxt, char *authlist)
428{
cb5eb4f1
PA
429 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
430 authctxt->method->cleanup(authctxt);
431
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432 if (authctxt->methoddata) {
433 xfree(authctxt->methoddata);
434 authctxt->methoddata = NULL;
435 }
436 if (authlist == NULL) {
437 authlist = authctxt->authlist;
438 } else {
439 if (authctxt->authlist)
440 xfree(authctxt->authlist);
441 authctxt->authlist = authlist;
442 }
443 for (;;) {
444 Authmethod *method = authmethod_get(authlist);
445 if (method == NULL)
446 fatal("Permission denied (%s).", authlist);
447 authctxt->method = method;
448
449 /* reset the per method handler */
450 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN,
451 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL);
452
453 /* and try new method */
454 if (method->userauth(authctxt) != 0) {
455 debug2("we sent a %s packet, wait for reply", method->name);
456 break;
457 } else {
458 debug2("we did not send a packet, disable method");
459 method->enabled = NULL;
460 }
461 }
462}
463
cb5eb4f1 464/* ARGSUSED */
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465void
466input_userauth_error(int type, u_int32_t seq, void *ctxt)
467{
468 fatal("input_userauth_error: bad message during authentication: "
469 "type %d", type);
470}
471
cb5eb4f1 472/* ARGSUSED */
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473void
474input_userauth_banner(int type, u_int32_t seq, void *ctxt)
475{
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476 char *msg, *raw, *lang;
477 u_int len;
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478
479 debug3("input_userauth_banner");
3b69e377 480 raw = packet_get_string(&len);
16c343f1 481 lang = packet_get_string(NULL);
cb5eb4f1 482 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) {
3b69e377
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483 if (len > 65536)
484 len = 65536;
cb5eb4f1 485 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */
856ea928 486 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH);
16c343f1 487 fprintf(stderr, "%s", msg);
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PA
488 xfree(msg);
489 }
490 xfree(raw);
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491 xfree(lang);
492}
493
cb5eb4f1 494/* ARGSUSED */
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495void
496input_userauth_success(int type, u_int32_t seq, void *ctxt)
497{
498 Authctxt *authctxt = ctxt;
856ea928 499
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500 if (authctxt == NULL)
501 fatal("input_userauth_success: no authentication context");
502 if (authctxt->authlist) {
503 xfree(authctxt->authlist);
504 authctxt->authlist = NULL;
505 }
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506 if (authctxt->method != NULL && authctxt->method->cleanup != NULL)
507 authctxt->method->cleanup(authctxt);
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508 if (authctxt->methoddata) {
509 xfree(authctxt->methoddata);
510 authctxt->methoddata = NULL;
511 }
512 authctxt->success = 1; /* break out */
513}
514
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PA
515void
516input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt)
517{
518 Authctxt *authctxt = ctxt;
519
520 if (authctxt == NULL)
521 fatal("%s: no authentication context", __func__);
522
523 fatal("Unexpected authentication success during %s.",
524 authctxt->method->name);
525}
526
cb5eb4f1 527/* ARGSUSED */
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528void
529input_userauth_failure(int type, u_int32_t seq, void *ctxt)
530{
531 Authctxt *authctxt = ctxt;
532 char *authlist = NULL;
533 int partial;
534
535 if (authctxt == NULL)
536 fatal("input_userauth_failure: no authentication context");
537
538 authlist = packet_get_string(NULL);
539 partial = packet_get_char();
540 packet_check_eom();
541
542 if (partial != 0)
543 logit("Authenticated with partial success.");
544 debug("Authentications that can continue: %s", authlist);
545
546 userauth(authctxt, authlist);
547}
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548
549/* ARGSUSED */
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550void
551input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt)
552{
553 Authctxt *authctxt = ctxt;
554 Key *key = NULL;
555 Identity *id = NULL;
556 Buffer b;
557 int pktype, sent = 0;
558 u_int alen, blen;
559 char *pkalg, *fp;
560 u_char *pkblob;
561
562 if (authctxt == NULL)
563 fatal("input_userauth_pk_ok: no authentication context");
564 if (datafellows & SSH_BUG_PKOK) {
565 /* this is similar to SSH_BUG_PKAUTH */
566 debug2("input_userauth_pk_ok: SSH_BUG_PKOK");
567 pkblob = packet_get_string(&blen);
568 buffer_init(&b);
569 buffer_append(&b, pkblob, blen);
570 pkalg = buffer_get_string(&b, &alen);
571 buffer_free(&b);
572 } else {
573 pkalg = packet_get_string(&alen);
574 pkblob = packet_get_string(&blen);
575 }
576 packet_check_eom();
577
578 debug("Server accepts key: pkalg %s blen %u", pkalg, blen);
579
580 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) {
581 debug("unknown pkalg %s", pkalg);
582 goto done;
583 }
584 if ((key = key_from_blob(pkblob, blen)) == NULL) {
585 debug("no key from blob. pkalg %s", pkalg);
586 goto done;
587 }
588 if (key->type != pktype) {
589 error("input_userauth_pk_ok: type mismatch "
590 "for decoded key (received %d, expected %d)",
591 key->type, pktype);
592 goto done;
593 }
594 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
595 debug2("input_userauth_pk_ok: fp %s", fp);
596 xfree(fp);
597
598 /*
599 * search keys in the reverse order, because last candidate has been
600 * moved to the end of the queue. this also avoids confusion by
601 * duplicate keys
602 */
603 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) {
604 if (key_equal(key, id->key)) {
605 sent = sign_and_send_pubkey(authctxt, id);
606 break;
607 }
608 }
609done:
610 if (key != NULL)
611 key_free(key);
612 xfree(pkalg);
613 xfree(pkblob);
614
615 /* try another method if we did not send a packet */
616 if (sent == 0)
617 userauth(authctxt, NULL);
618}
619
620#ifdef GSSAPI
621int
622userauth_gssapi(Authctxt *authctxt)
623{
624 Gssctxt *gssctxt = NULL;
625 static gss_OID_set gss_supported = NULL;
626 static u_int mech = 0;
627 OM_uint32 min;
628 int ok = 0;
629
630 /* Try one GSSAPI method at a time, rather than sending them all at
631 * once. */
632
633 if (gss_supported == NULL)
634 gss_indicate_mechs(&min, &gss_supported);
635
636 /* Check to see if the mechanism is usable before we offer it */
637 while (mech < gss_supported->count && !ok) {
638 /* My DER encoding requires length<128 */
639 if (gss_supported->elements[mech].length < 128 &&
640 ssh_gssapi_check_mechanism(&gssctxt,
641 &gss_supported->elements[mech], authctxt->host)) {
642 ok = 1; /* Mechanism works */
643 } else {
644 mech++;
645 }
646 }
647
648 if (!ok)
649 return 0;
650
651 authctxt->methoddata=(void *)gssctxt;
652
653 packet_start(SSH2_MSG_USERAUTH_REQUEST);
654 packet_put_cstring(authctxt->server_user);
655 packet_put_cstring(authctxt->service);
656 packet_put_cstring(authctxt->method->name);
657
658 packet_put_int(1);
659
660 packet_put_int((gss_supported->elements[mech].length) + 2);
661 packet_put_char(SSH_GSS_OIDTYPE);
662 packet_put_char(gss_supported->elements[mech].length);
663 packet_put_raw(gss_supported->elements[mech].elements,
664 gss_supported->elements[mech].length);
665
666 packet_send();
667
668 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response);
669 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token);
670 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error);
671 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok);
672
673 mech++; /* Move along to next candidate */
674
675 return 1;
676}
677
678static OM_uint32
679process_gssapi_token(void *ctxt, gss_buffer_t recv_tok)
680{
681 Authctxt *authctxt = ctxt;
682 Gssctxt *gssctxt = authctxt->methoddata;
683 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
684 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER;
685 gss_buffer_desc gssbuf;
686 OM_uint32 status, ms, flags;
687 Buffer b;
688
689 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
690 recv_tok, &send_tok, &flags);
691
692 if (send_tok.length > 0) {
693 if (GSS_ERROR(status))
694 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK);
695 else
696 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN);
697
698 packet_put_string(send_tok.value, send_tok.length);
699 packet_send();
700 gss_release_buffer(&ms, &send_tok);
701 }
702
703 if (status == GSS_S_COMPLETE) {
704 /* send either complete or MIC, depending on mechanism */
705 if (!(flags & GSS_C_INTEG_FLAG)) {
706 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE);
707 packet_send();
708 } else {
709 ssh_gssapi_buildmic(&b, authctxt->server_user,
710 authctxt->service, "gssapi-with-mic");
711
712 gssbuf.value = buffer_ptr(&b);
713 gssbuf.length = buffer_len(&b);
714
715 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic);
716
717 if (!GSS_ERROR(status)) {
718 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC);
719 packet_put_string(mic.value, mic.length);
720
721 packet_send();
722 }
723
724 buffer_free(&b);
725 gss_release_buffer(&ms, &mic);
726 }
727 }
728
729 return status;
730}
731
cb5eb4f1 732/* ARGSUSED */
16c343f1
PA
733void
734input_gssapi_response(int type, u_int32_t plen, void *ctxt)
735{
736 Authctxt *authctxt = ctxt;
737 Gssctxt *gssctxt;
738 int oidlen;
739 char *oidv;
740
741 if (authctxt == NULL)
742 fatal("input_gssapi_response: no authentication context");
743 gssctxt = authctxt->methoddata;
744
745 /* Setup our OID */
746 oidv = packet_get_string(&oidlen);
747
748 if (oidlen <= 2 ||
749 oidv[0] != SSH_GSS_OIDTYPE ||
750 oidv[1] != oidlen - 2) {
751 xfree(oidv);
752 debug("Badly encoded mechanism OID received");
753 userauth(authctxt, NULL);
754 return;
755 }
756
757 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2))
758 fatal("Server returned different OID than expected");
759
760 packet_check_eom();
761
762 xfree(oidv);
763
764 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) {
765 /* Start again with next method on list */
766 debug("Trying to start again");
767 userauth(authctxt, NULL);
768 return;
769 }
770}
771
cb5eb4f1 772/* ARGSUSED */
16c343f1
PA
773void
774input_gssapi_token(int type, u_int32_t plen, void *ctxt)
775{
776 Authctxt *authctxt = ctxt;
777 gss_buffer_desc recv_tok;
778 OM_uint32 status;
779 u_int slen;
780
781 if (authctxt == NULL)
782 fatal("input_gssapi_response: no authentication context");
783
784 recv_tok.value = packet_get_string(&slen);
785 recv_tok.length = slen; /* safe typecast */
786
787 packet_check_eom();
788
789 status = process_gssapi_token(ctxt, &recv_tok);
790
791 xfree(recv_tok.value);
792
793 if (GSS_ERROR(status)) {
794 /* Start again with the next method in the list */
795 userauth(authctxt, NULL);
796 return;
797 }
798}
799
cb5eb4f1 800/* ARGSUSED */
16c343f1
PA
801void
802input_gssapi_errtok(int type, u_int32_t plen, void *ctxt)
803{
804 Authctxt *authctxt = ctxt;
805 Gssctxt *gssctxt;
806 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER;
807 gss_buffer_desc recv_tok;
808 OM_uint32 status, ms;
809 u_int len;
810
811 if (authctxt == NULL)
812 fatal("input_gssapi_response: no authentication context");
813 gssctxt = authctxt->methoddata;
814
815 recv_tok.value = packet_get_string(&len);
816 recv_tok.length = len;
817
818 packet_check_eom();
819
820 /* Stick it into GSSAPI and see what it says */
821 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds,
822 &recv_tok, &send_tok, NULL);
823
824 xfree(recv_tok.value);
825 gss_release_buffer(&ms, &send_tok);
826
827 /* Server will be returning a failed packet after this one */
828}
829
cb5eb4f1 830/* ARGSUSED */
16c343f1
PA
831void
832input_gssapi_error(int type, u_int32_t plen, void *ctxt)
833{
834 OM_uint32 maj, min;
835 char *msg;
836 char *lang;
837
838 maj=packet_get_int();
839 min=packet_get_int();
840 msg=packet_get_string(NULL);
841 lang=packet_get_string(NULL);
842
843 packet_check_eom();
844
845 debug("Server GSSAPI Error:\n%s", msg);
846 xfree(msg);
847 xfree(lang);
848}
849#endif /* GSSAPI */
850
851int
852userauth_none(Authctxt *authctxt)
853{
854 /* initial userauth request */
855 packet_start(SSH2_MSG_USERAUTH_REQUEST);
856 packet_put_cstring(authctxt->server_user);
857 packet_put_cstring(authctxt->service);
858 packet_put_cstring(authctxt->method->name);
859 packet_send();
860 return 1;
861}
862
863int
864userauth_passwd(Authctxt *authctxt)
865{
866 static int attempt = 0;
867 char prompt[150];
868 char *password;
856ea928
PA
869 const char *host = options.host_key_alias ? options.host_key_alias :
870 authctxt->host;
16c343f1
PA
871
872 if (attempt++ >= options.number_of_password_prompts)
873 return 0;
874
875 if (attempt != 1)
876 error("Permission denied, please try again.");
877
878 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ",
856ea928 879 authctxt->server_user, host);
16c343f1
PA
880 password = read_passphrase(prompt, 0);
881 packet_start(SSH2_MSG_USERAUTH_REQUEST);
882 packet_put_cstring(authctxt->server_user);
883 packet_put_cstring(authctxt->service);
884 packet_put_cstring(authctxt->method->name);
885 packet_put_char(0);
886 packet_put_cstring(password);
887 memset(password, 0, strlen(password));
888 xfree(password);
889 packet_add_padding(64);
890 packet_send();
891
892 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
893 &input_userauth_passwd_changereq);
894
895 return 1;
896}
cb5eb4f1 897
16c343f1
PA
898/*
899 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST
900 */
cb5eb4f1 901/* ARGSUSED */
16c343f1
PA
902void
903input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt)
904{
905 Authctxt *authctxt = ctxt;
906 char *info, *lang, *password = NULL, *retype = NULL;
907 char prompt[150];
856ea928
PA
908 const char *host = options.host_key_alias ? options.host_key_alias :
909 authctxt->host;
16c343f1
PA
910
911 debug2("input_userauth_passwd_changereq");
912
913 if (authctxt == NULL)
914 fatal("input_userauth_passwd_changereq: "
915 "no authentication context");
916
917 info = packet_get_string(NULL);
918 lang = packet_get_string(NULL);
919 if (strlen(info) > 0)
920 logit("%s", info);
921 xfree(info);
922 xfree(lang);
923 packet_start(SSH2_MSG_USERAUTH_REQUEST);
924 packet_put_cstring(authctxt->server_user);
925 packet_put_cstring(authctxt->service);
926 packet_put_cstring(authctxt->method->name);
927 packet_put_char(1); /* additional info */
928 snprintf(prompt, sizeof(prompt),
929 "Enter %.30s@%.128s's old password: ",
856ea928 930 authctxt->server_user, host);
16c343f1
PA
931 password = read_passphrase(prompt, 0);
932 packet_put_cstring(password);
933 memset(password, 0, strlen(password));
934 xfree(password);
935 password = NULL;
936 while (password == NULL) {
937 snprintf(prompt, sizeof(prompt),
938 "Enter %.30s@%.128s's new password: ",
856ea928 939 authctxt->server_user, host);
16c343f1
PA
940 password = read_passphrase(prompt, RP_ALLOW_EOF);
941 if (password == NULL) {
942 /* bail out */
943 return;
944 }
945 snprintf(prompt, sizeof(prompt),
946 "Retype %.30s@%.128s's new password: ",
856ea928 947 authctxt->server_user, host);
16c343f1
PA
948 retype = read_passphrase(prompt, 0);
949 if (strcmp(password, retype) != 0) {
950 memset(password, 0, strlen(password));
951 xfree(password);
952 logit("Mismatch; try again, EOF to quit.");
953 password = NULL;
954 }
955 memset(retype, 0, strlen(retype));
956 xfree(retype);
957 }
958 packet_put_cstring(password);
959 memset(password, 0, strlen(password));
960 xfree(password);
961 packet_add_padding(64);
962 packet_send();
963
964 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ,
965 &input_userauth_passwd_changereq);
966}
967
cb5eb4f1
PA
968#ifdef JPAKE
969static char *
970pw_encrypt(const char *password, const char *crypt_scheme, const char *salt)
971{
972 /* OpenBSD crypt(3) handles all of these */
973 if (strcmp(crypt_scheme, "crypt") == 0 ||
974 strcmp(crypt_scheme, "bcrypt") == 0 ||
975 strcmp(crypt_scheme, "md5crypt") == 0 ||
976 strcmp(crypt_scheme, "crypt-extended") == 0)
977 return xstrdup(crypt(password, salt));
978 error("%s: unsupported password encryption scheme \"%.100s\"",
979 __func__, crypt_scheme);
980 return NULL;
981}
982
983static BIGNUM *
984jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme,
985 const char *salt)
986{
987 char prompt[256], *password, *crypted;
988 u_char *secret;
989 u_int secret_len;
990 BIGNUM *ret;
991
992 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ",
993 authctxt->server_user, authctxt->host);
994 password = read_passphrase(prompt, 0);
995
996 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) {
997 logit("Disabling %s authentication", authctxt->method->name);
998 authctxt->method->enabled = NULL;
999 /* Continue with an empty password to fail gracefully */
1000 crypted = xstrdup("");
1001 }
1002
1003#ifdef JPAKE_DEBUG
1004 debug3("%s: salt = %s", __func__, salt);
1005 debug3("%s: scheme = %s", __func__, crypt_scheme);
1006 debug3("%s: crypted = %s", __func__, crypted);
1007#endif
1008
1009 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(),
1010 &secret, &secret_len) != 0)
1011 fatal("%s: hash_buffer", __func__);
1012
1013 bzero(password, strlen(password));
1014 bzero(crypted, strlen(crypted));
1015 xfree(password);
1016 xfree(crypted);
1017
1018 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL)
1019 fatal("%s: BN_bin2bn (secret)", __func__);
1020 bzero(secret, secret_len);
1021 xfree(secret);
1022
1023 return ret;
1024}
1025
1026/* ARGSUSED */
1027void
1028input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt)
1029{
1030 Authctxt *authctxt = ctxt;
1031 struct jpake_ctx *pctx = authctxt->methoddata;
1032 u_char *x3_proof, *x4_proof, *x2_s_proof;
1033 u_int x3_proof_len, x4_proof_len, x2_s_proof_len;
1034 char *crypt_scheme, *salt;
1035
1036 /* Disable this message */
1037 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL);
1038
1039 if ((pctx->g_x3 = BN_new()) == NULL ||
1040 (pctx->g_x4 = BN_new()) == NULL)
1041 fatal("%s: BN_new", __func__);
1042
1043 /* Fetch step 1 values */
1044 crypt_scheme = packet_get_string(NULL);
1045 salt = packet_get_string(NULL);
1046 pctx->server_id = packet_get_string(&pctx->server_id_len);
1047 packet_get_bignum2(pctx->g_x3);
1048 packet_get_bignum2(pctx->g_x4);
1049 x3_proof = packet_get_string(&x3_proof_len);
1050 x4_proof = packet_get_string(&x4_proof_len);
1051 packet_check_eom();
1052
1053 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__));
1054
1055 /* Obtain password and derive secret */
1056 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt);
1057 bzero(crypt_scheme, strlen(crypt_scheme));
1058 bzero(salt, strlen(salt));
1059 xfree(crypt_scheme);
1060 xfree(salt);
1061 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__));
1062
1063 /* Calculate step 2 values */
1064 jpake_step2(pctx->grp, pctx->s, pctx->g_x1,
1065 pctx->g_x3, pctx->g_x4, pctx->x2,
1066 pctx->server_id, pctx->server_id_len,
1067 pctx->client_id, pctx->client_id_len,
1068 x3_proof, x3_proof_len,
1069 x4_proof, x4_proof_len,
1070 &pctx->a,
1071 &x2_s_proof, &x2_s_proof_len);
1072
1073 bzero(x3_proof, x3_proof_len);
1074 bzero(x4_proof, x4_proof_len);
1075 xfree(x3_proof);
1076 xfree(x4_proof);
1077
1078 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__));
1079
1080 /* Send values for step 2 */
1081 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2);
1082 packet_put_bignum2(pctx->a);
1083 packet_put_string(x2_s_proof, x2_s_proof_len);
1084 packet_send();
1085
1086 bzero(x2_s_proof, x2_s_proof_len);
1087 xfree(x2_s_proof);
1088
1089 /* Expect step 2 packet from peer */
1090 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2,
1091 input_userauth_jpake_server_step2);
1092}
1093
1094/* ARGSUSED */
1095void
1096input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt)
1097{
1098 Authctxt *authctxt = ctxt;
1099 struct jpake_ctx *pctx = authctxt->methoddata;
1100 u_char *x4_s_proof;
1101 u_int x4_s_proof_len;
1102
1103 /* Disable this message */
1104 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL);
1105
1106 if ((pctx->b = BN_new()) == NULL)
1107 fatal("%s: BN_new", __func__);
1108
1109 /* Fetch step 2 values */
1110 packet_get_bignum2(pctx->b);
1111 x4_s_proof = packet_get_string(&x4_s_proof_len);
1112 packet_check_eom();
1113
1114 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__));
1115
1116 /* Derive shared key and calculate confirmation hash */
1117 jpake_key_confirm(pctx->grp, pctx->s, pctx->b,
1118 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4,
1119 pctx->client_id, pctx->client_id_len,
1120 pctx->server_id, pctx->server_id_len,
1121 session_id2, session_id2_len,
1122 x4_s_proof, x4_s_proof_len,
1123 &pctx->k,
1124 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len);
1125
1126 bzero(x4_s_proof, x4_s_proof_len);
1127 xfree(x4_s_proof);
1128
1129 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__));
1130
1131 /* Send key confirmation proof */
1132 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM);
1133 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len);
1134 packet_send();
1135
1136 /* Expect confirmation from peer */
1137 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM,
1138 input_userauth_jpake_server_confirm);
1139}
1140
1141/* ARGSUSED */
1142void
1143input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt)
1144{
1145 Authctxt *authctxt = ctxt;
1146 struct jpake_ctx *pctx = authctxt->methoddata;
1147
1148 /* Disable this message */
1149 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL);
1150
1151 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len);
1152 packet_check_eom();
1153
1154 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__));
1155
1156 /* Verify expected confirmation hash */
1157 if (jpake_check_confirm(pctx->k,
1158 pctx->server_id, pctx->server_id_len,
1159 session_id2, session_id2_len,
1160 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1)
1161 debug("%s: %s success", __func__, authctxt->method->name);
1162 else {
1163 debug("%s: confirmation mismatch", __func__);
1164 /* XXX stash this so if auth succeeds then we can warn/kill */
1165 }
1166
1167 userauth_jpake_cleanup(authctxt);
1168}
1169#endif /* JPAKE */
1170
16c343f1
PA
1171static int
1172identity_sign(Identity *id, u_char **sigp, u_int *lenp,
1173 u_char *data, u_int datalen)
1174{
1175 Key *prv;
1176 int ret;
1177
1178 /* the agent supports this key */
1179 if (id->ac)
1180 return (ssh_agent_sign(id->ac, id->key, sigp, lenp,
1181 data, datalen));
1182 /*
1183 * we have already loaded the private key or
1184 * the private key is stored in external hardware
1185 */
1186 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT))
1187 return (key_sign(id->key, sigp, lenp, data, datalen));
1188 /* load the private key from the file */
1189 if ((prv = load_identity_file(id->filename)) == NULL)
1190 return (-1);
1191 ret = key_sign(prv, sigp, lenp, data, datalen);
1192 key_free(prv);
1193 return (ret);
1194}
1195
1196static int
1197sign_and_send_pubkey(Authctxt *authctxt, Identity *id)
1198{
1199 Buffer b;
1200 u_char *blob, *signature;
1201 u_int bloblen, slen;
1202 u_int skip = 0;
1203 int ret = -1;
1204 int have_sig = 1;
856ea928 1205 char *fp;
16c343f1 1206
856ea928
PA
1207 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX);
1208 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp);
1209 xfree(fp);
16c343f1
PA
1210
1211 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1212 /* we cannot handle this key */
1213 debug3("sign_and_send_pubkey: cannot handle key");
1214 return 0;
1215 }
1216 /* data to be signed */
1217 buffer_init(&b);
1218 if (datafellows & SSH_OLD_SESSIONID) {
1219 buffer_append(&b, session_id2, session_id2_len);
1220 skip = session_id2_len;
1221 } else {
1222 buffer_put_string(&b, session_id2, session_id2_len);
1223 skip = buffer_len(&b);
1224 }
1225 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1226 buffer_put_cstring(&b, authctxt->server_user);
1227 buffer_put_cstring(&b,
1228 datafellows & SSH_BUG_PKSERVICE ?
1229 "ssh-userauth" :
1230 authctxt->service);
1231 if (datafellows & SSH_BUG_PKAUTH) {
1232 buffer_put_char(&b, have_sig);
1233 } else {
1234 buffer_put_cstring(&b, authctxt->method->name);
1235 buffer_put_char(&b, have_sig);
1236 buffer_put_cstring(&b, key_ssh_name(id->key));
1237 }
1238 buffer_put_string(&b, blob, bloblen);
1239
1240 /* generate signature */
1241 ret = identity_sign(id, &signature, &slen,
1242 buffer_ptr(&b), buffer_len(&b));
1243 if (ret == -1) {
1244 xfree(blob);
1245 buffer_free(&b);
1246 return 0;
1247 }
1248#ifdef DEBUG_PK
1249 buffer_dump(&b);
1250#endif
1251 if (datafellows & SSH_BUG_PKSERVICE) {
1252 buffer_clear(&b);
1253 buffer_append(&b, session_id2, session_id2_len);
1254 skip = session_id2_len;
1255 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1256 buffer_put_cstring(&b, authctxt->server_user);
1257 buffer_put_cstring(&b, authctxt->service);
1258 buffer_put_cstring(&b, authctxt->method->name);
1259 buffer_put_char(&b, have_sig);
1260 if (!(datafellows & SSH_BUG_PKAUTH))
1261 buffer_put_cstring(&b, key_ssh_name(id->key));
1262 buffer_put_string(&b, blob, bloblen);
1263 }
1264 xfree(blob);
1265
1266 /* append signature */
1267 buffer_put_string(&b, signature, slen);
1268 xfree(signature);
1269
1270 /* skip session id and packet type */
1271 if (buffer_len(&b) < skip + 1)
1272 fatal("userauth_pubkey: internal error");
1273 buffer_consume(&b, skip + 1);
1274
1275 /* put remaining data from buffer into packet */
1276 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1277 packet_put_raw(buffer_ptr(&b), buffer_len(&b));
1278 buffer_free(&b);
1279 packet_send();
1280
1281 return 1;
1282}
1283
1284static int
1285send_pubkey_test(Authctxt *authctxt, Identity *id)
1286{
1287 u_char *blob;
1288 u_int bloblen, have_sig = 0;
1289
1290 debug3("send_pubkey_test");
1291
1292 if (key_to_blob(id->key, &blob, &bloblen) == 0) {
1293 /* we cannot handle this key */
1294 debug3("send_pubkey_test: cannot handle key");
1295 return 0;
1296 }
1297 /* register callback for USERAUTH_PK_OK message */
1298 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok);
1299
1300 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1301 packet_put_cstring(authctxt->server_user);
1302 packet_put_cstring(authctxt->service);
1303 packet_put_cstring(authctxt->method->name);
1304 packet_put_char(have_sig);
1305 if (!(datafellows & SSH_BUG_PKAUTH))
1306 packet_put_cstring(key_ssh_name(id->key));
1307 packet_put_string(blob, bloblen);
1308 xfree(blob);
1309 packet_send();
1310 return 1;
1311}
1312
1313static Key *
1314load_identity_file(char *filename)
1315{
1316 Key *private;
1317 char prompt[300], *passphrase;
856ea928 1318 int perm_ok = 0, quit, i;
16c343f1
PA
1319 struct stat st;
1320
1321 if (stat(filename, &st) < 0) {
1322 debug3("no such identity: %s", filename);
1323 return NULL;
1324 }
1325 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok);
1326 if (!perm_ok)
1327 return NULL;
1328 if (private == NULL) {
1329 if (options.batch_mode)
1330 return NULL;
1331 snprintf(prompt, sizeof prompt,
1332 "Enter passphrase for key '%.100s': ", filename);
1333 for (i = 0; i < options.number_of_password_prompts; i++) {
1334 passphrase = read_passphrase(prompt, 0);
1335 if (strcmp(passphrase, "") != 0) {
1336 private = key_load_private_type(KEY_UNSPEC,
1337 filename, passphrase, NULL, NULL);
1338 quit = 0;
1339 } else {
1340 debug2("no passphrase given, try next key");
1341 quit = 1;
1342 }
1343 memset(passphrase, 0, strlen(passphrase));
1344 xfree(passphrase);
1345 if (private != NULL || quit)
1346 break;
1347 debug2("bad passphrase given, try again...");
1348 }
1349 }
1350 return private;
1351}
1352
1353/*
1354 * try keys in the following order:
1355 * 1. agent keys that are found in the config file
1356 * 2. other agent keys
1357 * 3. keys that are only listed in the config file
1358 */
1359static void
1360pubkey_prepare(Authctxt *authctxt)
1361{
1362 Identity *id;
1363 Idlist agent, files, *preferred;
1364 Key *key;
1365 AuthenticationConnection *ac;
1366 char *comment;
1367 int i, found;
1368
1369 TAILQ_INIT(&agent); /* keys from the agent */
1370 TAILQ_INIT(&files); /* keys from the config file */
1371 preferred = &authctxt->keys;
1372 TAILQ_INIT(preferred); /* preferred order of keys */
1373
1374 /* list of keys stored in the filesystem */
1375 for (i = 0; i < options.num_identity_files; i++) {
1376 key = options.identity_keys[i];
1377 if (key && key->type == KEY_RSA1)
1378 continue;
856ea928
PA
1379 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER)
1380 continue;
16c343f1
PA
1381 options.identity_keys[i] = NULL;
1382 id = xcalloc(1, sizeof(*id));
1383 id->key = key;
1384 id->filename = xstrdup(options.identity_files[i]);
1385 TAILQ_INSERT_TAIL(&files, id, next);
1386 }
1387 /* list of keys supported by the agent */
1388 if ((ac = ssh_get_authentication_connection())) {
1389 for (key = ssh_get_first_identity(ac, &comment, 2);
1390 key != NULL;
1391 key = ssh_get_next_identity(ac, &comment, 2)) {
1392 found = 0;
1393 TAILQ_FOREACH(id, &files, next) {
1394 /* agent keys from the config file are preferred */
1395 if (key_equal(key, id->key)) {
1396 key_free(key);
1397 xfree(comment);
1398 TAILQ_REMOVE(&files, id, next);
1399 TAILQ_INSERT_TAIL(preferred, id, next);
1400 id->ac = ac;
1401 found = 1;
1402 break;
1403 }
1404 }
1405 if (!found && !options.identities_only) {
1406 id = xcalloc(1, sizeof(*id));
1407 id->key = key;
1408 id->filename = comment;
1409 id->ac = ac;
1410 TAILQ_INSERT_TAIL(&agent, id, next);
1411 }
1412 }
1413 /* append remaining agent keys */
1414 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) {
1415 TAILQ_REMOVE(&agent, id, next);
1416 TAILQ_INSERT_TAIL(preferred, id, next);
1417 }
1418 authctxt->agent = ac;
1419 }
1420 /* append remaining keys from the config file */
1421 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) {
1422 TAILQ_REMOVE(&files, id, next);
1423 TAILQ_INSERT_TAIL(preferred, id, next);
1424 }
1425 TAILQ_FOREACH(id, preferred, next) {
1426 debug2("key: %s (%p)", id->filename, id->key);
1427 }
1428}
1429
1430static void
1431pubkey_cleanup(Authctxt *authctxt)
1432{
1433 Identity *id;
1434
1435 if (authctxt->agent != NULL)
1436 ssh_close_authentication_connection(authctxt->agent);
1437 for (id = TAILQ_FIRST(&authctxt->keys); id;
1438 id = TAILQ_FIRST(&authctxt->keys)) {
1439 TAILQ_REMOVE(&authctxt->keys, id, next);
1440 if (id->key)
1441 key_free(id->key);
1442 if (id->filename)
1443 xfree(id->filename);
1444 xfree(id);
1445 }
1446}
1447
1448int
1449userauth_pubkey(Authctxt *authctxt)
1450{
1451 Identity *id;
1452 int sent = 0;
1453
1454 while ((id = TAILQ_FIRST(&authctxt->keys))) {
1455 if (id->tried++)
1456 return (0);
1457 /* move key to the end of the queue */
1458 TAILQ_REMOVE(&authctxt->keys, id, next);
1459 TAILQ_INSERT_TAIL(&authctxt->keys, id, next);
1460 /*
1461 * send a test message if we have the public key. for
1462 * encrypted keys we cannot do this and have to load the
1463 * private key instead
1464 */
1465 if (id->key && id->key->type != KEY_RSA1) {
856ea928
PA
1466 debug("Offering %s public key: %s", key_type(id->key),
1467 id->filename);
16c343f1
PA
1468 sent = send_pubkey_test(authctxt, id);
1469 } else if (id->key == NULL) {
1470 debug("Trying private key: %s", id->filename);
1471 id->key = load_identity_file(id->filename);
1472 if (id->key != NULL) {
1473 id->isprivate = 1;
1474 sent = sign_and_send_pubkey(authctxt, id);
1475 key_free(id->key);
1476 id->key = NULL;
1477 }
1478 }
1479 if (sent)
1480 return (sent);
1481 }
1482 return (0);
1483}
1484
1485/*
1486 * Send userauth request message specifying keyboard-interactive method.
1487 */
1488int
1489userauth_kbdint(Authctxt *authctxt)
1490{
1491 static int attempt = 0;
1492
1493 if (attempt++ >= options.number_of_password_prompts)
1494 return 0;
1495 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */
1496 if (attempt > 1 && !authctxt->info_req_seen) {
1497 debug3("userauth_kbdint: disable: no info_req_seen");
1498 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL);
1499 return 0;
1500 }
1501
1502 debug2("userauth_kbdint");
1503 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1504 packet_put_cstring(authctxt->server_user);
1505 packet_put_cstring(authctxt->service);
1506 packet_put_cstring(authctxt->method->name);
1507 packet_put_cstring(""); /* lang */
1508 packet_put_cstring(options.kbd_interactive_devices ?
1509 options.kbd_interactive_devices : "");
1510 packet_send();
1511
1512 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req);
1513 return 1;
1514}
1515
1516/*
1517 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE
1518 */
1519void
1520input_userauth_info_req(int type, u_int32_t seq, void *ctxt)
1521{
1522 Authctxt *authctxt = ctxt;
1523 char *name, *inst, *lang, *prompt, *response;
1524 u_int num_prompts, i;
1525 int echo = 0;
1526
1527 debug2("input_userauth_info_req");
1528
1529 if (authctxt == NULL)
1530 fatal("input_userauth_info_req: no authentication context");
1531
1532 authctxt->info_req_seen = 1;
1533
1534 name = packet_get_string(NULL);
1535 inst = packet_get_string(NULL);
1536 lang = packet_get_string(NULL);
1537 if (strlen(name) > 0)
1538 logit("%s", name);
1539 if (strlen(inst) > 0)
1540 logit("%s", inst);
1541 xfree(name);
1542 xfree(inst);
1543 xfree(lang);
1544
1545 num_prompts = packet_get_int();
1546 /*
1547 * Begin to build info response packet based on prompts requested.
1548 * We commit to providing the correct number of responses, so if
1549 * further on we run into a problem that prevents this, we have to
1550 * be sure and clean this up and send a correct error response.
1551 */
1552 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE);
1553 packet_put_int(num_prompts);
1554
1555 debug2("input_userauth_info_req: num_prompts %d", num_prompts);
1556 for (i = 0; i < num_prompts; i++) {
1557 prompt = packet_get_string(NULL);
1558 echo = packet_get_char();
1559
1560 response = read_passphrase(prompt, echo ? RP_ECHO : 0);
1561
1562 packet_put_cstring(response);
1563 memset(response, 0, strlen(response));
1564 xfree(response);
1565 xfree(prompt);
1566 }
1567 packet_check_eom(); /* done with parsing incoming message. */
1568
1569 packet_add_padding(64);
1570 packet_send();
1571}
1572
1573static int
1574ssh_keysign(Key *key, u_char **sigp, u_int *lenp,
1575 u_char *data, u_int datalen)
1576{
1577 Buffer b;
1578 struct stat st;
1579 pid_t pid;
1580 int to[2], from[2], status, version = 2;
1581
1582 debug2("ssh_keysign called");
1583
1584 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) {
856ea928 1585 error("ssh_keysign: not installed: %s", strerror(errno));
16c343f1
PA
1586 return -1;
1587 }
1588 if (fflush(stdout) != 0)
1589 error("ssh_keysign: fflush: %s", strerror(errno));
1590 if (pipe(to) < 0) {
1591 error("ssh_keysign: pipe: %s", strerror(errno));
1592 return -1;
1593 }
1594 if (pipe(from) < 0) {
1595 error("ssh_keysign: pipe: %s", strerror(errno));
1596 return -1;
1597 }
1598 if ((pid = fork()) < 0) {
1599 error("ssh_keysign: fork: %s", strerror(errno));
1600 return -1;
1601 }
1602 if (pid == 0) {
856ea928
PA
1603 /* keep the socket on exec */
1604 fcntl(packet_get_connection_in(), F_SETFD, 0);
16c343f1
PA
1605 permanently_drop_suid(getuid());
1606 close(from[0]);
1607 if (dup2(from[1], STDOUT_FILENO) < 0)
1608 fatal("ssh_keysign: dup2: %s", strerror(errno));
1609 close(to[1]);
1610 if (dup2(to[0], STDIN_FILENO) < 0)
1611 fatal("ssh_keysign: dup2: %s", strerror(errno));
1612 close(from[1]);
1613 close(to[0]);
1614 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0);
1615 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN,
1616 strerror(errno));
1617 }
1618 close(from[1]);
1619 close(to[0]);
1620
1621 buffer_init(&b);
1622 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */
1623 buffer_put_string(&b, data, datalen);
1624 if (ssh_msg_send(to[1], version, &b) == -1)
1625 fatal("ssh_keysign: couldn't send request");
1626
1627 if (ssh_msg_recv(from[0], &b) < 0) {
1628 error("ssh_keysign: no reply");
1629 buffer_free(&b);
1630 return -1;
1631 }
1632 close(from[0]);
1633 close(to[1]);
1634
1635 while (waitpid(pid, &status, 0) < 0)
1636 if (errno != EINTR)
1637 break;
1638
1639 if (buffer_get_char(&b) != version) {
1640 error("ssh_keysign: bad version");
1641 buffer_free(&b);
1642 return -1;
1643 }
1644 *sigp = buffer_get_string(&b, lenp);
1645 buffer_free(&b);
1646
1647 return 0;
1648}
1649
1650int
1651userauth_hostbased(Authctxt *authctxt)
1652{
1653 Key *private = NULL;
1654 Sensitive *sensitive = authctxt->sensitive;
1655 Buffer b;
1656 u_char *signature, *blob;
856ea928 1657 char *chost, *pkalg, *p;
16c343f1
PA
1658 const char *service;
1659 u_int blen, slen;
856ea928 1660 int ok, i, found = 0;
16c343f1
PA
1661
1662 /* check for a useful key */
1663 for (i = 0; i < sensitive->nkeys; i++) {
1664 private = sensitive->keys[i];
1665 if (private && private->type != KEY_RSA1) {
1666 found = 1;
1667 /* we take and free the key */
1668 sensitive->keys[i] = NULL;
1669 break;
1670 }
1671 }
1672 if (!found) {
1673 debug("No more client hostkeys for hostbased authentication.");
1674 return 0;
1675 }
1676 if (key_to_blob(private, &blob, &blen) == 0) {
1677 key_free(private);
1678 return 0;
1679 }
1680 /* figure out a name for the client host */
856ea928 1681 p = get_local_name(packet_get_connection_in());
16c343f1
PA
1682 if (p == NULL) {
1683 error("userauth_hostbased: cannot get local ipaddr/name");
1684 key_free(private);
1685 xfree(blob);
1686 return 0;
1687 }
16c343f1
PA
1688 xasprintf(&chost, "%s.", p);
1689 debug2("userauth_hostbased: chost %s", chost);
1690 xfree(p);
1691
1692 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
1693 authctxt->service;
1694 pkalg = xstrdup(key_ssh_name(private));
1695 buffer_init(&b);
1696 /* construct data */
1697 buffer_put_string(&b, session_id2, session_id2_len);
1698 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
1699 buffer_put_cstring(&b, authctxt->server_user);
1700 buffer_put_cstring(&b, service);
1701 buffer_put_cstring(&b, authctxt->method->name);
1702 buffer_put_cstring(&b, pkalg);
1703 buffer_put_string(&b, blob, blen);
1704 buffer_put_cstring(&b, chost);
1705 buffer_put_cstring(&b, authctxt->local_user);
1706#ifdef DEBUG_PK
1707 buffer_dump(&b);
1708#endif
1709 if (sensitive->external_keysign)
1710 ok = ssh_keysign(private, &signature, &slen,
1711 buffer_ptr(&b), buffer_len(&b));
1712 else
1713 ok = key_sign(private, &signature, &slen,
1714 buffer_ptr(&b), buffer_len(&b));
1715 key_free(private);
1716 buffer_free(&b);
1717 if (ok != 0) {
1718 error("key_sign failed");
1719 xfree(chost);
1720 xfree(pkalg);
1721 xfree(blob);
1722 return 0;
1723 }
1724 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1725 packet_put_cstring(authctxt->server_user);
1726 packet_put_cstring(authctxt->service);
1727 packet_put_cstring(authctxt->method->name);
1728 packet_put_cstring(pkalg);
1729 packet_put_string(blob, blen);
1730 packet_put_cstring(chost);
1731 packet_put_cstring(authctxt->local_user);
1732 packet_put_string(signature, slen);
1733 memset(signature, 's', slen);
1734 xfree(signature);
1735 xfree(chost);
1736 xfree(pkalg);
1737 xfree(blob);
1738
1739 packet_send();
1740 return 1;
1741}
1742
cb5eb4f1
PA
1743#ifdef JPAKE
1744int
1745userauth_jpake(Authctxt *authctxt)
1746{
1747 struct jpake_ctx *pctx;
1748 u_char *x1_proof, *x2_proof;
1749 u_int x1_proof_len, x2_proof_len;
1750 static int attempt = 0; /* XXX share with userauth_password's? */
1751
1752 if (attempt++ >= options.number_of_password_prompts)
1753 return 0;
1754 if (attempt != 1)
1755 error("Permission denied, please try again.");
1756
1757 if (authctxt->methoddata != NULL)
1758 fatal("%s: authctxt->methoddata already set (%p)",
1759 __func__, authctxt->methoddata);
1760
1761 authctxt->methoddata = pctx = jpake_new();
1762
1763 /*
1764 * Send request immediately, to get the protocol going while
1765 * we do the initial computations.
1766 */
1767 packet_start(SSH2_MSG_USERAUTH_REQUEST);
1768 packet_put_cstring(authctxt->server_user);
1769 packet_put_cstring(authctxt->service);
1770 packet_put_cstring(authctxt->method->name);
1771 packet_send();
1772 packet_write_wait();
1773
1774 jpake_step1(pctx->grp,
1775 &pctx->client_id, &pctx->client_id_len,
1776 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2,
1777 &x1_proof, &x1_proof_len,
1778 &x2_proof, &x2_proof_len);
1779
1780 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__));
1781
1782 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1);
1783 packet_put_string(pctx->client_id, pctx->client_id_len);
1784 packet_put_bignum2(pctx->g_x1);
1785 packet_put_bignum2(pctx->g_x2);
1786 packet_put_string(x1_proof, x1_proof_len);
1787 packet_put_string(x2_proof, x2_proof_len);
1788 packet_send();
1789
1790 bzero(x1_proof, x1_proof_len);
1791 bzero(x2_proof, x2_proof_len);
1792 xfree(x1_proof);
1793 xfree(x2_proof);
1794
1795 /* Expect step 1 packet from peer */
1796 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1,
1797 input_userauth_jpake_server_step1);
856ea928
PA
1798 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS,
1799 &input_userauth_success_unexpected);
cb5eb4f1
PA
1800
1801 return 1;
1802}
1803
1804void
1805userauth_jpake_cleanup(Authctxt *authctxt)
1806{
1807 debug3("%s: clean up", __func__);
1808 if (authctxt->methoddata != NULL) {
1809 jpake_free(authctxt->methoddata);
1810 authctxt->methoddata = NULL;
1811 }
856ea928 1812 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success);
cb5eb4f1
PA
1813}
1814#endif /* JPAKE */
1815
16c343f1
PA
1816/* find auth method */
1817
1818/*
1819 * given auth method name, if configurable options permit this method fill
1820 * in auth_ident field and return true, otherwise return false.
1821 */
1822static int
1823authmethod_is_enabled(Authmethod *method)
1824{
1825 if (method == NULL)
1826 return 0;
1827 /* return false if options indicate this method is disabled */
1828 if (method->enabled == NULL || *method->enabled == 0)
1829 return 0;
1830 /* return false if batch mode is enabled but method needs interactive mode */
1831 if (method->batch_flag != NULL && *method->batch_flag != 0)
1832 return 0;
1833 return 1;
1834}
1835
1836static Authmethod *
1837authmethod_lookup(const char *name)
1838{
1839 Authmethod *method = NULL;
1840 if (name != NULL)
1841 for (method = authmethods; method->name != NULL; method++)
1842 if (strcmp(name, method->name) == 0)
1843 return method;
1844 debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
1845 return NULL;
1846}
1847
1848/* XXX internal state */
1849static Authmethod *current = NULL;
1850static char *supported = NULL;
1851static char *preferred = NULL;
1852
1853/*
1854 * Given the authentication method list sent by the server, return the
1855 * next method we should try. If the server initially sends a nil list,
1856 * use a built-in default list.
1857 */
1858static Authmethod *
1859authmethod_get(char *authlist)
1860{
1861 char *name = NULL;
1862 u_int next;
1863
1864 /* Use a suitable default if we're passed a nil list. */
1865 if (authlist == NULL || strlen(authlist) == 0)
1866 authlist = options.preferred_authentications;
1867
1868 if (supported == NULL || strcmp(authlist, supported) != 0) {
1869 debug3("start over, passed a different list %s", authlist);
1870 if (supported != NULL)
1871 xfree(supported);
1872 supported = xstrdup(authlist);
1873 preferred = options.preferred_authentications;
1874 debug3("preferred %s", preferred);
1875 current = NULL;
1876 } else if (current != NULL && authmethod_is_enabled(current))
1877 return current;
1878
1879 for (;;) {
1880 if ((name = match_list(preferred, supported, &next)) == NULL) {
1881 debug("No more authentication methods to try.");
1882 current = NULL;
1883 return NULL;
1884 }
1885 preferred += next;
1886 debug3("authmethod_lookup %s", name);
1887 debug3("remaining preferred: %s", preferred);
1888 if ((current = authmethod_lookup(name)) != NULL &&
1889 authmethod_is_enabled(current)) {
1890 debug3("authmethod_is_enabled %s", name);
1891 debug("Next authentication method: %s", name);
1c188a7f 1892 xfree(name);
16c343f1
PA
1893 return current;
1894 }
1895 }
1c188a7f
PA
1896 if (name != NULL)
1897 xfree(name);
16c343f1
PA
1898}
1899
1900static char *
1901authmethods_get(void)
1902{
1903 Authmethod *method = NULL;
1904 Buffer b;
1905 char *list;
1906
1907 buffer_init(&b);
1908 for (method = authmethods; method->name != NULL; method++) {
1909 if (authmethod_is_enabled(method)) {
1910 if (buffer_len(&b) > 0)
1911 buffer_append(&b, ",", 1);
1912 buffer_append(&b, method->name, strlen(method->name));
1913 }
1914 }
1915 buffer_append(&b, "\0", 1);
1916 list = xstrdup(buffer_ptr(&b));
1917 buffer_free(&b);
1918 return list;
1919}
cb5eb4f1 1920