sshconnect2.c revision 215116
1/* $OpenBSD: sshconnect2.c,v 1.183 2010/04/26 22:28:24 djm Exp $ */ 2/* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include "includes.h" 28 29#include <sys/types.h> 30#include <sys/socket.h> 31#include <sys/wait.h> 32#include <sys/stat.h> 33 34#include <errno.h> 35#include <fcntl.h> 36#include <netdb.h> 37#include <pwd.h> 38#include <signal.h> 39#include <stdarg.h> 40#include <stdio.h> 41#include <string.h> 42#include <unistd.h> 43#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) 44#include <vis.h> 45#endif 46 47#include "openbsd-compat/sys-queue.h" 48 49#include "xmalloc.h" 50#include "ssh.h" 51#include "ssh2.h" 52#include "buffer.h" 53#include "packet.h" 54#include "compat.h" 55#include "cipher.h" 56#include "key.h" 57#include "kex.h" 58#include "myproposal.h" 59#include "sshconnect.h" 60#include "authfile.h" 61#include "dh.h" 62#include "authfd.h" 63#include "log.h" 64#include "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" 72#include "schnorr.h" 73#include "jpake.h" 74 75#ifdef GSSAPI 76#include "ssh-gss.h" 77#endif 78 79/* import */ 80extern char *client_version_string; 81extern char *server_version_string; 82extern Options options; 83 84/* 85 * SSH2 key exchange 86 */ 87 88u_char *session_id2 = NULL; 89u_int session_id2_len = 0; 90 91char *xxx_host; 92struct sockaddr *xxx_hostaddr; 93 94Kex *xxx_kex = NULL; 95 96static int 97verify_host_key_callback(Key *hostkey) 98{ 99 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 100 fatal("Host key verification failed."); 101 return 0; 102} 103 104void 105ssh_kex2(char *host, struct sockaddr *hostaddr) 106{ 107 Kex *kex; 108 109 xxx_host = host; 110 xxx_hostaddr = hostaddr; 111 112 if (options.ciphers == (char *)-1) { 113 logit("No valid ciphers for protocol version 2 given, using defaults."); 114 options.ciphers = NULL; 115 } 116 if (options.ciphers != NULL) { 117 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 118 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 119 } 120 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 121 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 122 myproposal[PROPOSAL_ENC_ALGS_STOC] = 123 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 124 if (options.compression) { 125 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 126 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 127 } else { 128 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 129 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 130 } 131 if (options.macs != NULL) { 132 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 133 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 134 } 135 if (options.hostkeyalgorithms != NULL) 136 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 137 options.hostkeyalgorithms; 138 139 if (options.rekey_limit) 140 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 141 142 /* start key exchange */ 143 kex = kex_setup(myproposal); 144 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 145 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 146 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 147 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 148 kex->client_version_string=client_version_string; 149 kex->server_version_string=server_version_string; 150 kex->verify_host_key=&verify_host_key_callback; 151 152 xxx_kex = kex; 153 154 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 155 156 if (options.use_roaming && !kex->roaming) { 157 debug("Roaming not allowed by server"); 158 options.use_roaming = 0; 159 } 160 161 session_id2 = kex->session_id; 162 session_id2_len = kex->session_id_len; 163 164#ifdef DEBUG_KEXDH 165 /* send 1st encrypted/maced/compressed message */ 166 packet_start(SSH2_MSG_IGNORE); 167 packet_put_cstring("markus"); 168 packet_send(); 169 packet_write_wait(); 170#endif 171} 172 173/* 174 * Authenticate user 175 */ 176 177typedef struct Authctxt Authctxt; 178typedef struct Authmethod Authmethod; 179typedef struct identity Identity; 180typedef struct idlist Idlist; 181 182struct identity { 183 TAILQ_ENTRY(identity) next; 184 AuthenticationConnection *ac; /* set if agent supports key */ 185 Key *key; /* public/private key */ 186 char *filename; /* comment for agent-only keys */ 187 int tried; 188 int isprivate; /* key points to the private key */ 189}; 190TAILQ_HEAD(idlist, identity); 191 192struct Authctxt { 193 const char *server_user; 194 const char *local_user; 195 const char *host; 196 const char *service; 197 Authmethod *method; 198 sig_atomic_t success; 199 char *authlist; 200 /* pubkey */ 201 Idlist keys; 202 AuthenticationConnection *agent; 203 /* hostbased */ 204 Sensitive *sensitive; 205 /* kbd-interactive */ 206 int info_req_seen; 207 /* generic */ 208 void *methoddata; 209}; 210struct Authmethod { 211 char *name; /* string to compare against server's list */ 212 int (*userauth)(Authctxt *authctxt); 213 void (*cleanup)(Authctxt *authctxt); 214 int *enabled; /* flag in option struct that enables method */ 215 int *batch_flag; /* flag in option struct that disables method */ 216}; 217 218void input_userauth_success(int, u_int32_t, void *); 219void input_userauth_success_unexpected(int, u_int32_t, void *); 220void input_userauth_failure(int, u_int32_t, void *); 221void input_userauth_banner(int, u_int32_t, void *); 222void input_userauth_error(int, u_int32_t, void *); 223void input_userauth_info_req(int, u_int32_t, void *); 224void input_userauth_pk_ok(int, u_int32_t, void *); 225void input_userauth_passwd_changereq(int, u_int32_t, void *); 226void input_userauth_jpake_server_step1(int, u_int32_t, void *); 227void input_userauth_jpake_server_step2(int, u_int32_t, void *); 228void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 229 230int userauth_none(Authctxt *); 231int userauth_pubkey(Authctxt *); 232int userauth_passwd(Authctxt *); 233int userauth_kbdint(Authctxt *); 234int userauth_hostbased(Authctxt *); 235int userauth_jpake(Authctxt *); 236 237void userauth_jpake_cleanup(Authctxt *); 238 239#ifdef GSSAPI 240int userauth_gssapi(Authctxt *authctxt); 241void input_gssapi_response(int type, u_int32_t, void *); 242void input_gssapi_token(int type, u_int32_t, void *); 243void input_gssapi_hash(int type, u_int32_t, void *); 244void input_gssapi_error(int, u_int32_t, void *); 245void input_gssapi_errtok(int, u_int32_t, void *); 246#endif 247 248void userauth(Authctxt *, char *); 249 250static int sign_and_send_pubkey(Authctxt *, Identity *); 251static void pubkey_prepare(Authctxt *); 252static void pubkey_cleanup(Authctxt *); 253static Key *load_identity_file(char *); 254 255static Authmethod *authmethod_get(char *authlist); 256static Authmethod *authmethod_lookup(const char *name); 257static char *authmethods_get(void); 258 259Authmethod authmethods[] = { 260#ifdef GSSAPI 261 {"gssapi-with-mic", 262 userauth_gssapi, 263 NULL, 264 &options.gss_authentication, 265 NULL}, 266#endif 267 {"hostbased", 268 userauth_hostbased, 269 NULL, 270 &options.hostbased_authentication, 271 NULL}, 272 {"publickey", 273 userauth_pubkey, 274 NULL, 275 &options.pubkey_authentication, 276 NULL}, 277#ifdef JPAKE 278 {"jpake-01@openssh.com", 279 userauth_jpake, 280 userauth_jpake_cleanup, 281 &options.zero_knowledge_password_authentication, 282 &options.batch_mode}, 283#endif 284 {"keyboard-interactive", 285 userauth_kbdint, 286 NULL, 287 &options.kbd_interactive_authentication, 288 &options.batch_mode}, 289 {"password", 290 userauth_passwd, 291 NULL, 292 &options.password_authentication, 293 &options.batch_mode}, 294 {"none", 295 userauth_none, 296 NULL, 297 NULL, 298 NULL}, 299 {NULL, NULL, NULL, NULL, NULL} 300}; 301 302void 303ssh_userauth2(const char *local_user, const char *server_user, char *host, 304 Sensitive *sensitive) 305{ 306 Authctxt authctxt; 307 int type; 308 309 if (options.challenge_response_authentication) 310 options.kbd_interactive_authentication = 1; 311 312 packet_start(SSH2_MSG_SERVICE_REQUEST); 313 packet_put_cstring("ssh-userauth"); 314 packet_send(); 315 debug("SSH2_MSG_SERVICE_REQUEST sent"); 316 packet_write_wait(); 317 type = packet_read(); 318 if (type != SSH2_MSG_SERVICE_ACCEPT) 319 fatal("Server denied authentication request: %d", type); 320 if (packet_remaining() > 0) { 321 char *reply = packet_get_string(NULL); 322 debug2("service_accept: %s", reply); 323 xfree(reply); 324 } else { 325 debug2("buggy server: service_accept w/o service"); 326 } 327 packet_check_eom(); 328 debug("SSH2_MSG_SERVICE_ACCEPT received"); 329 330 if (options.preferred_authentications == NULL) 331 options.preferred_authentications = authmethods_get(); 332 333 /* setup authentication context */ 334 memset(&authctxt, 0, sizeof(authctxt)); 335 pubkey_prepare(&authctxt); 336 authctxt.server_user = server_user; 337 authctxt.local_user = local_user; 338 authctxt.host = host; 339 authctxt.service = "ssh-connection"; /* service name */ 340 authctxt.success = 0; 341 authctxt.method = authmethod_lookup("none"); 342 authctxt.authlist = NULL; 343 authctxt.methoddata = NULL; 344 authctxt.sensitive = sensitive; 345 authctxt.info_req_seen = 0; 346 if (authctxt.method == NULL) 347 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 348 349 /* initial userauth request */ 350 userauth_none(&authctxt); 351 352 dispatch_init(&input_userauth_error); 353 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 354 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 355 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 356 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 357 358 pubkey_cleanup(&authctxt); 359 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 360 361 debug("Authentication succeeded (%s).", authctxt.method->name); 362} 363 364void 365userauth(Authctxt *authctxt, char *authlist) 366{ 367 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 368 authctxt->method->cleanup(authctxt); 369 370 if (authctxt->methoddata) { 371 xfree(authctxt->methoddata); 372 authctxt->methoddata = NULL; 373 } 374 if (authlist == NULL) { 375 authlist = authctxt->authlist; 376 } else { 377 if (authctxt->authlist) 378 xfree(authctxt->authlist); 379 authctxt->authlist = authlist; 380 } 381 for (;;) { 382 Authmethod *method = authmethod_get(authlist); 383 if (method == NULL) 384 fatal("Permission denied (%s).", authlist); 385 authctxt->method = method; 386 387 /* reset the per method handler */ 388 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 389 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 390 391 /* and try new method */ 392 if (method->userauth(authctxt) != 0) { 393 debug2("we sent a %s packet, wait for reply", method->name); 394 break; 395 } else { 396 debug2("we did not send a packet, disable method"); 397 method->enabled = NULL; 398 } 399 } 400} 401 402/* ARGSUSED */ 403void 404input_userauth_error(int type, u_int32_t seq, void *ctxt) 405{ 406 fatal("input_userauth_error: bad message during authentication: " 407 "type %d", type); 408} 409 410/* ARGSUSED */ 411void 412input_userauth_banner(int type, u_int32_t seq, void *ctxt) 413{ 414 char *msg, *raw, *lang; 415 u_int len; 416 417 debug3("input_userauth_banner"); 418 raw = packet_get_string(&len); 419 lang = packet_get_string(NULL); 420 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 421 if (len > 65536) 422 len = 65536; 423 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 424 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 425 fprintf(stderr, "%s", msg); 426 xfree(msg); 427 } 428 xfree(raw); 429 xfree(lang); 430} 431 432/* ARGSUSED */ 433void 434input_userauth_success(int type, u_int32_t seq, void *ctxt) 435{ 436 Authctxt *authctxt = ctxt; 437 438 if (authctxt == NULL) 439 fatal("input_userauth_success: no authentication context"); 440 if (authctxt->authlist) { 441 xfree(authctxt->authlist); 442 authctxt->authlist = NULL; 443 } 444 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 445 authctxt->method->cleanup(authctxt); 446 if (authctxt->methoddata) { 447 xfree(authctxt->methoddata); 448 authctxt->methoddata = NULL; 449 } 450 authctxt->success = 1; /* break out */ 451} 452 453void 454input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 455{ 456 Authctxt *authctxt = ctxt; 457 458 if (authctxt == NULL) 459 fatal("%s: no authentication context", __func__); 460 461 fatal("Unexpected authentication success during %s.", 462 authctxt->method->name); 463} 464 465/* ARGSUSED */ 466void 467input_userauth_failure(int type, u_int32_t seq, void *ctxt) 468{ 469 Authctxt *authctxt = ctxt; 470 char *authlist = NULL; 471 int partial; 472 473 if (authctxt == NULL) 474 fatal("input_userauth_failure: no authentication context"); 475 476 authlist = packet_get_string(NULL); 477 partial = packet_get_char(); 478 packet_check_eom(); 479 480 if (partial != 0) 481 logit("Authenticated with partial success."); 482 debug("Authentications that can continue: %s", authlist); 483 484 userauth(authctxt, authlist); 485} 486 487/* ARGSUSED */ 488void 489input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 490{ 491 Authctxt *authctxt = ctxt; 492 Key *key = NULL; 493 Identity *id = NULL; 494 Buffer b; 495 int pktype, sent = 0; 496 u_int alen, blen; 497 char *pkalg, *fp; 498 u_char *pkblob; 499 500 if (authctxt == NULL) 501 fatal("input_userauth_pk_ok: no authentication context"); 502 if (datafellows & SSH_BUG_PKOK) { 503 /* this is similar to SSH_BUG_PKAUTH */ 504 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 505 pkblob = packet_get_string(&blen); 506 buffer_init(&b); 507 buffer_append(&b, pkblob, blen); 508 pkalg = buffer_get_string(&b, &alen); 509 buffer_free(&b); 510 } else { 511 pkalg = packet_get_string(&alen); 512 pkblob = packet_get_string(&blen); 513 } 514 packet_check_eom(); 515 516 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 517 518 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 519 debug("unknown pkalg %s", pkalg); 520 goto done; 521 } 522 if ((key = key_from_blob(pkblob, blen)) == NULL) { 523 debug("no key from blob. pkalg %s", pkalg); 524 goto done; 525 } 526 if (key->type != pktype) { 527 error("input_userauth_pk_ok: type mismatch " 528 "for decoded key (received %d, expected %d)", 529 key->type, pktype); 530 goto done; 531 } 532 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 533 debug2("input_userauth_pk_ok: fp %s", fp); 534 xfree(fp); 535 536 /* 537 * search keys in the reverse order, because last candidate has been 538 * moved to the end of the queue. this also avoids confusion by 539 * duplicate keys 540 */ 541 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 542 if (key_equal(key, id->key)) { 543 sent = sign_and_send_pubkey(authctxt, id); 544 break; 545 } 546 } 547done: 548 if (key != NULL) 549 key_free(key); 550 xfree(pkalg); 551 xfree(pkblob); 552 553 /* try another method if we did not send a packet */ 554 if (sent == 0) 555 userauth(authctxt, NULL); 556} 557 558#ifdef GSSAPI 559int 560userauth_gssapi(Authctxt *authctxt) 561{ 562 Gssctxt *gssctxt = NULL; 563 static gss_OID_set gss_supported = NULL; 564 static u_int mech = 0; 565 OM_uint32 min; 566 int ok = 0; 567 568 /* Try one GSSAPI method at a time, rather than sending them all at 569 * once. */ 570 571 if (gss_supported == NULL) 572 gss_indicate_mechs(&min, &gss_supported); 573 574 /* Check to see if the mechanism is usable before we offer it */ 575 while (mech < gss_supported->count && !ok) { 576 /* My DER encoding requires length<128 */ 577 if (gss_supported->elements[mech].length < 128 && 578 ssh_gssapi_check_mechanism(&gssctxt, 579 &gss_supported->elements[mech], authctxt->host)) { 580 ok = 1; /* Mechanism works */ 581 } else { 582 mech++; 583 } 584 } 585 586 if (!ok) 587 return 0; 588 589 authctxt->methoddata=(void *)gssctxt; 590 591 packet_start(SSH2_MSG_USERAUTH_REQUEST); 592 packet_put_cstring(authctxt->server_user); 593 packet_put_cstring(authctxt->service); 594 packet_put_cstring(authctxt->method->name); 595 596 packet_put_int(1); 597 598 packet_put_int((gss_supported->elements[mech].length) + 2); 599 packet_put_char(SSH_GSS_OIDTYPE); 600 packet_put_char(gss_supported->elements[mech].length); 601 packet_put_raw(gss_supported->elements[mech].elements, 602 gss_supported->elements[mech].length); 603 604 packet_send(); 605 606 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 607 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 608 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 609 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 610 611 mech++; /* Move along to next candidate */ 612 613 return 1; 614} 615 616static OM_uint32 617process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 618{ 619 Authctxt *authctxt = ctxt; 620 Gssctxt *gssctxt = authctxt->methoddata; 621 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 622 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 623 gss_buffer_desc gssbuf; 624 OM_uint32 status, ms, flags; 625 Buffer b; 626 627 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 628 recv_tok, &send_tok, &flags); 629 630 if (send_tok.length > 0) { 631 if (GSS_ERROR(status)) 632 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 633 else 634 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 635 636 packet_put_string(send_tok.value, send_tok.length); 637 packet_send(); 638 gss_release_buffer(&ms, &send_tok); 639 } 640 641 if (status == GSS_S_COMPLETE) { 642 /* send either complete or MIC, depending on mechanism */ 643 if (!(flags & GSS_C_INTEG_FLAG)) { 644 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 645 packet_send(); 646 } else { 647 ssh_gssapi_buildmic(&b, authctxt->server_user, 648 authctxt->service, "gssapi-with-mic"); 649 650 gssbuf.value = buffer_ptr(&b); 651 gssbuf.length = buffer_len(&b); 652 653 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 654 655 if (!GSS_ERROR(status)) { 656 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 657 packet_put_string(mic.value, mic.length); 658 659 packet_send(); 660 } 661 662 buffer_free(&b); 663 gss_release_buffer(&ms, &mic); 664 } 665 } 666 667 return status; 668} 669 670/* ARGSUSED */ 671void 672input_gssapi_response(int type, u_int32_t plen, void *ctxt) 673{ 674 Authctxt *authctxt = ctxt; 675 Gssctxt *gssctxt; 676 int oidlen; 677 char *oidv; 678 679 if (authctxt == NULL) 680 fatal("input_gssapi_response: no authentication context"); 681 gssctxt = authctxt->methoddata; 682 683 /* Setup our OID */ 684 oidv = packet_get_string(&oidlen); 685 686 if (oidlen <= 2 || 687 oidv[0] != SSH_GSS_OIDTYPE || 688 oidv[1] != oidlen - 2) { 689 xfree(oidv); 690 debug("Badly encoded mechanism OID received"); 691 userauth(authctxt, NULL); 692 return; 693 } 694 695 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 696 fatal("Server returned different OID than expected"); 697 698 packet_check_eom(); 699 700 xfree(oidv); 701 702 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 703 /* Start again with next method on list */ 704 debug("Trying to start again"); 705 userauth(authctxt, NULL); 706 return; 707 } 708} 709 710/* ARGSUSED */ 711void 712input_gssapi_token(int type, u_int32_t plen, void *ctxt) 713{ 714 Authctxt *authctxt = ctxt; 715 gss_buffer_desc recv_tok; 716 OM_uint32 status; 717 u_int slen; 718 719 if (authctxt == NULL) 720 fatal("input_gssapi_response: no authentication context"); 721 722 recv_tok.value = packet_get_string(&slen); 723 recv_tok.length = slen; /* safe typecast */ 724 725 packet_check_eom(); 726 727 status = process_gssapi_token(ctxt, &recv_tok); 728 729 xfree(recv_tok.value); 730 731 if (GSS_ERROR(status)) { 732 /* Start again with the next method in the list */ 733 userauth(authctxt, NULL); 734 return; 735 } 736} 737 738/* ARGSUSED */ 739void 740input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 741{ 742 Authctxt *authctxt = ctxt; 743 Gssctxt *gssctxt; 744 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 745 gss_buffer_desc recv_tok; 746 OM_uint32 status, ms; 747 u_int len; 748 749 if (authctxt == NULL) 750 fatal("input_gssapi_response: no authentication context"); 751 gssctxt = authctxt->methoddata; 752 753 recv_tok.value = packet_get_string(&len); 754 recv_tok.length = len; 755 756 packet_check_eom(); 757 758 /* Stick it into GSSAPI and see what it says */ 759 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 760 &recv_tok, &send_tok, NULL); 761 762 xfree(recv_tok.value); 763 gss_release_buffer(&ms, &send_tok); 764 765 /* Server will be returning a failed packet after this one */ 766} 767 768/* ARGSUSED */ 769void 770input_gssapi_error(int type, u_int32_t plen, void *ctxt) 771{ 772 OM_uint32 maj, min; 773 char *msg; 774 char *lang; 775 776 maj=packet_get_int(); 777 min=packet_get_int(); 778 msg=packet_get_string(NULL); 779 lang=packet_get_string(NULL); 780 781 packet_check_eom(); 782 783 debug("Server GSSAPI Error:\n%s", msg); 784 xfree(msg); 785 xfree(lang); 786} 787#endif /* GSSAPI */ 788 789int 790userauth_none(Authctxt *authctxt) 791{ 792 /* initial userauth request */ 793 packet_start(SSH2_MSG_USERAUTH_REQUEST); 794 packet_put_cstring(authctxt->server_user); 795 packet_put_cstring(authctxt->service); 796 packet_put_cstring(authctxt->method->name); 797 packet_send(); 798 return 1; 799} 800 801int 802userauth_passwd(Authctxt *authctxt) 803{ 804 static int attempt = 0; 805 char prompt[150]; 806 char *password; 807 const char *host = options.host_key_alias ? options.host_key_alias : 808 authctxt->host; 809 810 if (attempt++ >= options.number_of_password_prompts) 811 return 0; 812 813 if (attempt != 1) 814 error("Permission denied, please try again."); 815 816 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 817 authctxt->server_user, host); 818 password = read_passphrase(prompt, 0); 819 packet_start(SSH2_MSG_USERAUTH_REQUEST); 820 packet_put_cstring(authctxt->server_user); 821 packet_put_cstring(authctxt->service); 822 packet_put_cstring(authctxt->method->name); 823 packet_put_char(0); 824 packet_put_cstring(password); 825 memset(password, 0, strlen(password)); 826 xfree(password); 827 packet_add_padding(64); 828 packet_send(); 829 830 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 831 &input_userauth_passwd_changereq); 832 833 return 1; 834} 835 836/* 837 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 838 */ 839/* ARGSUSED */ 840void 841input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 842{ 843 Authctxt *authctxt = ctxt; 844 char *info, *lang, *password = NULL, *retype = NULL; 845 char prompt[150]; 846 const char *host = options.host_key_alias ? options.host_key_alias : 847 authctxt->host; 848 849 debug2("input_userauth_passwd_changereq"); 850 851 if (authctxt == NULL) 852 fatal("input_userauth_passwd_changereq: " 853 "no authentication context"); 854 855 info = packet_get_string(NULL); 856 lang = packet_get_string(NULL); 857 if (strlen(info) > 0) 858 logit("%s", info); 859 xfree(info); 860 xfree(lang); 861 packet_start(SSH2_MSG_USERAUTH_REQUEST); 862 packet_put_cstring(authctxt->server_user); 863 packet_put_cstring(authctxt->service); 864 packet_put_cstring(authctxt->method->name); 865 packet_put_char(1); /* additional info */ 866 snprintf(prompt, sizeof(prompt), 867 "Enter %.30s@%.128s's old password: ", 868 authctxt->server_user, host); 869 password = read_passphrase(prompt, 0); 870 packet_put_cstring(password); 871 memset(password, 0, strlen(password)); 872 xfree(password); 873 password = NULL; 874 while (password == NULL) { 875 snprintf(prompt, sizeof(prompt), 876 "Enter %.30s@%.128s's new password: ", 877 authctxt->server_user, host); 878 password = read_passphrase(prompt, RP_ALLOW_EOF); 879 if (password == NULL) { 880 /* bail out */ 881 return; 882 } 883 snprintf(prompt, sizeof(prompt), 884 "Retype %.30s@%.128s's new password: ", 885 authctxt->server_user, host); 886 retype = read_passphrase(prompt, 0); 887 if (strcmp(password, retype) != 0) { 888 memset(password, 0, strlen(password)); 889 xfree(password); 890 logit("Mismatch; try again, EOF to quit."); 891 password = NULL; 892 } 893 memset(retype, 0, strlen(retype)); 894 xfree(retype); 895 } 896 packet_put_cstring(password); 897 memset(password, 0, strlen(password)); 898 xfree(password); 899 packet_add_padding(64); 900 packet_send(); 901 902 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 903 &input_userauth_passwd_changereq); 904} 905 906#ifdef JPAKE 907static char * 908pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 909{ 910 /* OpenBSD crypt(3) handles all of these */ 911 if (strcmp(crypt_scheme, "crypt") == 0 || 912 strcmp(crypt_scheme, "bcrypt") == 0 || 913 strcmp(crypt_scheme, "md5crypt") == 0 || 914 strcmp(crypt_scheme, "crypt-extended") == 0) 915 return xstrdup(crypt(password, salt)); 916 error("%s: unsupported password encryption scheme \"%.100s\"", 917 __func__, crypt_scheme); 918 return NULL; 919} 920 921static BIGNUM * 922jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 923 const char *salt) 924{ 925 char prompt[256], *password, *crypted; 926 u_char *secret; 927 u_int secret_len; 928 BIGNUM *ret; 929 930 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 931 authctxt->server_user, authctxt->host); 932 password = read_passphrase(prompt, 0); 933 934 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 935 logit("Disabling %s authentication", authctxt->method->name); 936 authctxt->method->enabled = NULL; 937 /* Continue with an empty password to fail gracefully */ 938 crypted = xstrdup(""); 939 } 940 941#ifdef JPAKE_DEBUG 942 debug3("%s: salt = %s", __func__, salt); 943 debug3("%s: scheme = %s", __func__, crypt_scheme); 944 debug3("%s: crypted = %s", __func__, crypted); 945#endif 946 947 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 948 &secret, &secret_len) != 0) 949 fatal("%s: hash_buffer", __func__); 950 951 bzero(password, strlen(password)); 952 bzero(crypted, strlen(crypted)); 953 xfree(password); 954 xfree(crypted); 955 956 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 957 fatal("%s: BN_bin2bn (secret)", __func__); 958 bzero(secret, secret_len); 959 xfree(secret); 960 961 return ret; 962} 963 964/* ARGSUSED */ 965void 966input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 967{ 968 Authctxt *authctxt = ctxt; 969 struct jpake_ctx *pctx = authctxt->methoddata; 970 u_char *x3_proof, *x4_proof, *x2_s_proof; 971 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 972 char *crypt_scheme, *salt; 973 974 /* Disable this message */ 975 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 976 977 if ((pctx->g_x3 = BN_new()) == NULL || 978 (pctx->g_x4 = BN_new()) == NULL) 979 fatal("%s: BN_new", __func__); 980 981 /* Fetch step 1 values */ 982 crypt_scheme = packet_get_string(NULL); 983 salt = packet_get_string(NULL); 984 pctx->server_id = packet_get_string(&pctx->server_id_len); 985 packet_get_bignum2(pctx->g_x3); 986 packet_get_bignum2(pctx->g_x4); 987 x3_proof = packet_get_string(&x3_proof_len); 988 x4_proof = packet_get_string(&x4_proof_len); 989 packet_check_eom(); 990 991 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 992 993 /* Obtain password and derive secret */ 994 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 995 bzero(crypt_scheme, strlen(crypt_scheme)); 996 bzero(salt, strlen(salt)); 997 xfree(crypt_scheme); 998 xfree(salt); 999 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1000 1001 /* Calculate step 2 values */ 1002 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1003 pctx->g_x3, pctx->g_x4, pctx->x2, 1004 pctx->server_id, pctx->server_id_len, 1005 pctx->client_id, pctx->client_id_len, 1006 x3_proof, x3_proof_len, 1007 x4_proof, x4_proof_len, 1008 &pctx->a, 1009 &x2_s_proof, &x2_s_proof_len); 1010 1011 bzero(x3_proof, x3_proof_len); 1012 bzero(x4_proof, x4_proof_len); 1013 xfree(x3_proof); 1014 xfree(x4_proof); 1015 1016 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1017 1018 /* Send values for step 2 */ 1019 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1020 packet_put_bignum2(pctx->a); 1021 packet_put_string(x2_s_proof, x2_s_proof_len); 1022 packet_send(); 1023 1024 bzero(x2_s_proof, x2_s_proof_len); 1025 xfree(x2_s_proof); 1026 1027 /* Expect step 2 packet from peer */ 1028 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1029 input_userauth_jpake_server_step2); 1030} 1031 1032/* ARGSUSED */ 1033void 1034input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1035{ 1036 Authctxt *authctxt = ctxt; 1037 struct jpake_ctx *pctx = authctxt->methoddata; 1038 u_char *x4_s_proof; 1039 u_int x4_s_proof_len; 1040 1041 /* Disable this message */ 1042 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1043 1044 if ((pctx->b = BN_new()) == NULL) 1045 fatal("%s: BN_new", __func__); 1046 1047 /* Fetch step 2 values */ 1048 packet_get_bignum2(pctx->b); 1049 x4_s_proof = packet_get_string(&x4_s_proof_len); 1050 packet_check_eom(); 1051 1052 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1053 1054 /* Derive shared key and calculate confirmation hash */ 1055 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1056 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1057 pctx->client_id, pctx->client_id_len, 1058 pctx->server_id, pctx->server_id_len, 1059 session_id2, session_id2_len, 1060 x4_s_proof, x4_s_proof_len, 1061 &pctx->k, 1062 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1063 1064 bzero(x4_s_proof, x4_s_proof_len); 1065 xfree(x4_s_proof); 1066 1067 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1068 1069 /* Send key confirmation proof */ 1070 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1071 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1072 packet_send(); 1073 1074 /* Expect confirmation from peer */ 1075 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1076 input_userauth_jpake_server_confirm); 1077} 1078 1079/* ARGSUSED */ 1080void 1081input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1082{ 1083 Authctxt *authctxt = ctxt; 1084 struct jpake_ctx *pctx = authctxt->methoddata; 1085 1086 /* Disable this message */ 1087 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1088 1089 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1090 packet_check_eom(); 1091 1092 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1093 1094 /* Verify expected confirmation hash */ 1095 if (jpake_check_confirm(pctx->k, 1096 pctx->server_id, pctx->server_id_len, 1097 session_id2, session_id2_len, 1098 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1099 debug("%s: %s success", __func__, authctxt->method->name); 1100 else { 1101 debug("%s: confirmation mismatch", __func__); 1102 /* XXX stash this so if auth succeeds then we can warn/kill */ 1103 } 1104 1105 userauth_jpake_cleanup(authctxt); 1106} 1107#endif /* JPAKE */ 1108 1109static int 1110identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1111 u_char *data, u_int datalen) 1112{ 1113 Key *prv; 1114 int ret; 1115 1116 /* the agent supports this key */ 1117 if (id->ac) 1118 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1119 data, datalen)); 1120 /* 1121 * we have already loaded the private key or 1122 * the private key is stored in external hardware 1123 */ 1124 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1125 return (key_sign(id->key, sigp, lenp, data, datalen)); 1126 /* load the private key from the file */ 1127 if ((prv = load_identity_file(id->filename)) == NULL) 1128 return (-1); 1129 ret = key_sign(prv, sigp, lenp, data, datalen); 1130 key_free(prv); 1131 return (ret); 1132} 1133 1134static int 1135sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1136{ 1137 Buffer b; 1138 u_char *blob, *signature; 1139 u_int bloblen, slen; 1140 u_int skip = 0; 1141 int ret = -1; 1142 int have_sig = 1; 1143 char *fp; 1144 1145 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1146 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1147 xfree(fp); 1148 1149 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1150 /* we cannot handle this key */ 1151 debug3("sign_and_send_pubkey: cannot handle key"); 1152 return 0; 1153 } 1154 /* data to be signed */ 1155 buffer_init(&b); 1156 if (datafellows & SSH_OLD_SESSIONID) { 1157 buffer_append(&b, session_id2, session_id2_len); 1158 skip = session_id2_len; 1159 } else { 1160 buffer_put_string(&b, session_id2, session_id2_len); 1161 skip = buffer_len(&b); 1162 } 1163 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1164 buffer_put_cstring(&b, authctxt->server_user); 1165 buffer_put_cstring(&b, 1166 datafellows & SSH_BUG_PKSERVICE ? 1167 "ssh-userauth" : 1168 authctxt->service); 1169 if (datafellows & SSH_BUG_PKAUTH) { 1170 buffer_put_char(&b, have_sig); 1171 } else { 1172 buffer_put_cstring(&b, authctxt->method->name); 1173 buffer_put_char(&b, have_sig); 1174 buffer_put_cstring(&b, key_ssh_name(id->key)); 1175 } 1176 buffer_put_string(&b, blob, bloblen); 1177 1178 /* generate signature */ 1179 ret = identity_sign(id, &signature, &slen, 1180 buffer_ptr(&b), buffer_len(&b)); 1181 if (ret == -1) { 1182 xfree(blob); 1183 buffer_free(&b); 1184 return 0; 1185 } 1186#ifdef DEBUG_PK 1187 buffer_dump(&b); 1188#endif 1189 if (datafellows & SSH_BUG_PKSERVICE) { 1190 buffer_clear(&b); 1191 buffer_append(&b, session_id2, session_id2_len); 1192 skip = session_id2_len; 1193 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1194 buffer_put_cstring(&b, authctxt->server_user); 1195 buffer_put_cstring(&b, authctxt->service); 1196 buffer_put_cstring(&b, authctxt->method->name); 1197 buffer_put_char(&b, have_sig); 1198 if (!(datafellows & SSH_BUG_PKAUTH)) 1199 buffer_put_cstring(&b, key_ssh_name(id->key)); 1200 buffer_put_string(&b, blob, bloblen); 1201 } 1202 xfree(blob); 1203 1204 /* append signature */ 1205 buffer_put_string(&b, signature, slen); 1206 xfree(signature); 1207 1208 /* skip session id and packet type */ 1209 if (buffer_len(&b) < skip + 1) 1210 fatal("userauth_pubkey: internal error"); 1211 buffer_consume(&b, skip + 1); 1212 1213 /* put remaining data from buffer into packet */ 1214 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1215 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1216 buffer_free(&b); 1217 packet_send(); 1218 1219 return 1; 1220} 1221 1222static int 1223send_pubkey_test(Authctxt *authctxt, Identity *id) 1224{ 1225 u_char *blob; 1226 u_int bloblen, have_sig = 0; 1227 1228 debug3("send_pubkey_test"); 1229 1230 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1231 /* we cannot handle this key */ 1232 debug3("send_pubkey_test: cannot handle key"); 1233 return 0; 1234 } 1235 /* register callback for USERAUTH_PK_OK message */ 1236 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1237 1238 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1239 packet_put_cstring(authctxt->server_user); 1240 packet_put_cstring(authctxt->service); 1241 packet_put_cstring(authctxt->method->name); 1242 packet_put_char(have_sig); 1243 if (!(datafellows & SSH_BUG_PKAUTH)) 1244 packet_put_cstring(key_ssh_name(id->key)); 1245 packet_put_string(blob, bloblen); 1246 xfree(blob); 1247 packet_send(); 1248 return 1; 1249} 1250 1251static Key * 1252load_identity_file(char *filename) 1253{ 1254 Key *private; 1255 char prompt[300], *passphrase; 1256 int perm_ok = 0, quit, i; 1257 struct stat st; 1258 1259 if (stat(filename, &st) < 0) { 1260 debug3("no such identity: %s", filename); 1261 return NULL; 1262 } 1263 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1264 if (!perm_ok) 1265 return NULL; 1266 if (private == NULL) { 1267 if (options.batch_mode) 1268 return NULL; 1269 snprintf(prompt, sizeof prompt, 1270 "Enter passphrase for key '%.100s': ", filename); 1271 for (i = 0; i < options.number_of_password_prompts; i++) { 1272 passphrase = read_passphrase(prompt, 0); 1273 if (strcmp(passphrase, "") != 0) { 1274 private = key_load_private_type(KEY_UNSPEC, 1275 filename, passphrase, NULL, NULL); 1276 quit = 0; 1277 } else { 1278 debug2("no passphrase given, try next key"); 1279 quit = 1; 1280 } 1281 memset(passphrase, 0, strlen(passphrase)); 1282 xfree(passphrase); 1283 if (private != NULL || quit) 1284 break; 1285 debug2("bad passphrase given, try again..."); 1286 } 1287 } 1288 return private; 1289} 1290 1291/* 1292 * try keys in the following order: 1293 * 1. agent keys that are found in the config file 1294 * 2. other agent keys 1295 * 3. keys that are only listed in the config file 1296 */ 1297static void 1298pubkey_prepare(Authctxt *authctxt) 1299{ 1300 Identity *id; 1301 Idlist agent, files, *preferred; 1302 Key *key; 1303 AuthenticationConnection *ac; 1304 char *comment; 1305 int i, found; 1306 1307 TAILQ_INIT(&agent); /* keys from the agent */ 1308 TAILQ_INIT(&files); /* keys from the config file */ 1309 preferred = &authctxt->keys; 1310 TAILQ_INIT(preferred); /* preferred order of keys */ 1311 1312 /* list of keys stored in the filesystem */ 1313 for (i = 0; i < options.num_identity_files; i++) { 1314 key = options.identity_keys[i]; 1315 if (key && key->type == KEY_RSA1) 1316 continue; 1317 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1318 continue; 1319 options.identity_keys[i] = NULL; 1320 id = xcalloc(1, sizeof(*id)); 1321 id->key = key; 1322 id->filename = xstrdup(options.identity_files[i]); 1323 TAILQ_INSERT_TAIL(&files, id, next); 1324 } 1325 /* list of keys supported by the agent */ 1326 if ((ac = ssh_get_authentication_connection())) { 1327 for (key = ssh_get_first_identity(ac, &comment, 2); 1328 key != NULL; 1329 key = ssh_get_next_identity(ac, &comment, 2)) { 1330 found = 0; 1331 TAILQ_FOREACH(id, &files, next) { 1332 /* agent keys from the config file are preferred */ 1333 if (key_equal(key, id->key)) { 1334 key_free(key); 1335 xfree(comment); 1336 TAILQ_REMOVE(&files, id, next); 1337 TAILQ_INSERT_TAIL(preferred, id, next); 1338 id->ac = ac; 1339 found = 1; 1340 break; 1341 } 1342 } 1343 if (!found && !options.identities_only) { 1344 id = xcalloc(1, sizeof(*id)); 1345 id->key = key; 1346 id->filename = comment; 1347 id->ac = ac; 1348 TAILQ_INSERT_TAIL(&agent, id, next); 1349 } 1350 } 1351 /* append remaining agent keys */ 1352 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1353 TAILQ_REMOVE(&agent, id, next); 1354 TAILQ_INSERT_TAIL(preferred, id, next); 1355 } 1356 authctxt->agent = ac; 1357 } 1358 /* append remaining keys from the config file */ 1359 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1360 TAILQ_REMOVE(&files, id, next); 1361 TAILQ_INSERT_TAIL(preferred, id, next); 1362 } 1363 TAILQ_FOREACH(id, preferred, next) { 1364 debug2("key: %s (%p)", id->filename, id->key); 1365 } 1366} 1367 1368static void 1369pubkey_cleanup(Authctxt *authctxt) 1370{ 1371 Identity *id; 1372 1373 if (authctxt->agent != NULL) 1374 ssh_close_authentication_connection(authctxt->agent); 1375 for (id = TAILQ_FIRST(&authctxt->keys); id; 1376 id = TAILQ_FIRST(&authctxt->keys)) { 1377 TAILQ_REMOVE(&authctxt->keys, id, next); 1378 if (id->key) 1379 key_free(id->key); 1380 if (id->filename) 1381 xfree(id->filename); 1382 xfree(id); 1383 } 1384} 1385 1386int 1387userauth_pubkey(Authctxt *authctxt) 1388{ 1389 Identity *id; 1390 int sent = 0; 1391 1392 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1393 if (id->tried++) 1394 return (0); 1395 /* move key to the end of the queue */ 1396 TAILQ_REMOVE(&authctxt->keys, id, next); 1397 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1398 /* 1399 * send a test message if we have the public key. for 1400 * encrypted keys we cannot do this and have to load the 1401 * private key instead 1402 */ 1403 if (id->key && id->key->type != KEY_RSA1) { 1404 debug("Offering %s public key: %s", key_type(id->key), 1405 id->filename); 1406 sent = send_pubkey_test(authctxt, id); 1407 } else if (id->key == NULL) { 1408 debug("Trying private key: %s", id->filename); 1409 id->key = load_identity_file(id->filename); 1410 if (id->key != NULL) { 1411 id->isprivate = 1; 1412 sent = sign_and_send_pubkey(authctxt, id); 1413 key_free(id->key); 1414 id->key = NULL; 1415 } 1416 } 1417 if (sent) 1418 return (sent); 1419 } 1420 return (0); 1421} 1422 1423/* 1424 * Send userauth request message specifying keyboard-interactive method. 1425 */ 1426int 1427userauth_kbdint(Authctxt *authctxt) 1428{ 1429 static int attempt = 0; 1430 1431 if (attempt++ >= options.number_of_password_prompts) 1432 return 0; 1433 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1434 if (attempt > 1 && !authctxt->info_req_seen) { 1435 debug3("userauth_kbdint: disable: no info_req_seen"); 1436 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1437 return 0; 1438 } 1439 1440 debug2("userauth_kbdint"); 1441 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1442 packet_put_cstring(authctxt->server_user); 1443 packet_put_cstring(authctxt->service); 1444 packet_put_cstring(authctxt->method->name); 1445 packet_put_cstring(""); /* lang */ 1446 packet_put_cstring(options.kbd_interactive_devices ? 1447 options.kbd_interactive_devices : ""); 1448 packet_send(); 1449 1450 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1451 return 1; 1452} 1453 1454/* 1455 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1456 */ 1457void 1458input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1459{ 1460 Authctxt *authctxt = ctxt; 1461 char *name, *inst, *lang, *prompt, *response; 1462 u_int num_prompts, i; 1463 int echo = 0; 1464 1465 debug2("input_userauth_info_req"); 1466 1467 if (authctxt == NULL) 1468 fatal("input_userauth_info_req: no authentication context"); 1469 1470 authctxt->info_req_seen = 1; 1471 1472 name = packet_get_string(NULL); 1473 inst = packet_get_string(NULL); 1474 lang = packet_get_string(NULL); 1475 if (strlen(name) > 0) 1476 logit("%s", name); 1477 if (strlen(inst) > 0) 1478 logit("%s", inst); 1479 xfree(name); 1480 xfree(inst); 1481 xfree(lang); 1482 1483 num_prompts = packet_get_int(); 1484 /* 1485 * Begin to build info response packet based on prompts requested. 1486 * We commit to providing the correct number of responses, so if 1487 * further on we run into a problem that prevents this, we have to 1488 * be sure and clean this up and send a correct error response. 1489 */ 1490 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1491 packet_put_int(num_prompts); 1492 1493 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1494 for (i = 0; i < num_prompts; i++) { 1495 prompt = packet_get_string(NULL); 1496 echo = packet_get_char(); 1497 1498 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1499 1500 packet_put_cstring(response); 1501 memset(response, 0, strlen(response)); 1502 xfree(response); 1503 xfree(prompt); 1504 } 1505 packet_check_eom(); /* done with parsing incoming message. */ 1506 1507 packet_add_padding(64); 1508 packet_send(); 1509} 1510 1511static int 1512ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1513 u_char *data, u_int datalen) 1514{ 1515 Buffer b; 1516 struct stat st; 1517 pid_t pid; 1518 int to[2], from[2], status, version = 2; 1519 1520 debug2("ssh_keysign called"); 1521 1522 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1523 error("ssh_keysign: not installed: %s", strerror(errno)); 1524 return -1; 1525 } 1526 if (fflush(stdout) != 0) 1527 error("ssh_keysign: fflush: %s", strerror(errno)); 1528 if (pipe(to) < 0) { 1529 error("ssh_keysign: pipe: %s", strerror(errno)); 1530 return -1; 1531 } 1532 if (pipe(from) < 0) { 1533 error("ssh_keysign: pipe: %s", strerror(errno)); 1534 return -1; 1535 } 1536 if ((pid = fork()) < 0) { 1537 error("ssh_keysign: fork: %s", strerror(errno)); 1538 return -1; 1539 } 1540 if (pid == 0) { 1541 /* keep the socket on exec */ 1542 fcntl(packet_get_connection_in(), F_SETFD, 0); 1543 permanently_drop_suid(getuid()); 1544 close(from[0]); 1545 if (dup2(from[1], STDOUT_FILENO) < 0) 1546 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1547 close(to[1]); 1548 if (dup2(to[0], STDIN_FILENO) < 0) 1549 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1550 close(from[1]); 1551 close(to[0]); 1552 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1553 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1554 strerror(errno)); 1555 } 1556 close(from[1]); 1557 close(to[0]); 1558 1559 buffer_init(&b); 1560 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1561 buffer_put_string(&b, data, datalen); 1562 if (ssh_msg_send(to[1], version, &b) == -1) 1563 fatal("ssh_keysign: couldn't send request"); 1564 1565 if (ssh_msg_recv(from[0], &b) < 0) { 1566 error("ssh_keysign: no reply"); 1567 buffer_free(&b); 1568 return -1; 1569 } 1570 close(from[0]); 1571 close(to[1]); 1572 1573 while (waitpid(pid, &status, 0) < 0) 1574 if (errno != EINTR) 1575 break; 1576 1577 if (buffer_get_char(&b) != version) { 1578 error("ssh_keysign: bad version"); 1579 buffer_free(&b); 1580 return -1; 1581 } 1582 *sigp = buffer_get_string(&b, lenp); 1583 buffer_free(&b); 1584 1585 return 0; 1586} 1587 1588int 1589userauth_hostbased(Authctxt *authctxt) 1590{ 1591 Key *private = NULL; 1592 Sensitive *sensitive = authctxt->sensitive; 1593 Buffer b; 1594 u_char *signature, *blob; 1595 char *chost, *pkalg, *p; 1596 const char *service; 1597 u_int blen, slen; 1598 int ok, i, found = 0; 1599 1600 /* check for a useful key */ 1601 for (i = 0; i < sensitive->nkeys; i++) { 1602 private = sensitive->keys[i]; 1603 if (private && private->type != KEY_RSA1) { 1604 found = 1; 1605 /* we take and free the key */ 1606 sensitive->keys[i] = NULL; 1607 break; 1608 } 1609 } 1610 if (!found) { 1611 debug("No more client hostkeys for hostbased authentication."); 1612 return 0; 1613 } 1614 if (key_to_blob(private, &blob, &blen) == 0) { 1615 key_free(private); 1616 return 0; 1617 } 1618 /* figure out a name for the client host */ 1619 p = get_local_name(packet_get_connection_in()); 1620 if (p == NULL) { 1621 error("userauth_hostbased: cannot get local ipaddr/name"); 1622 key_free(private); 1623 xfree(blob); 1624 return 0; 1625 } 1626 xasprintf(&chost, "%s.", p); 1627 debug2("userauth_hostbased: chost %s", chost); 1628 xfree(p); 1629 1630 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1631 authctxt->service; 1632 pkalg = xstrdup(key_ssh_name(private)); 1633 buffer_init(&b); 1634 /* construct data */ 1635 buffer_put_string(&b, session_id2, session_id2_len); 1636 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1637 buffer_put_cstring(&b, authctxt->server_user); 1638 buffer_put_cstring(&b, service); 1639 buffer_put_cstring(&b, authctxt->method->name); 1640 buffer_put_cstring(&b, pkalg); 1641 buffer_put_string(&b, blob, blen); 1642 buffer_put_cstring(&b, chost); 1643 buffer_put_cstring(&b, authctxt->local_user); 1644#ifdef DEBUG_PK 1645 buffer_dump(&b); 1646#endif 1647 if (sensitive->external_keysign) 1648 ok = ssh_keysign(private, &signature, &slen, 1649 buffer_ptr(&b), buffer_len(&b)); 1650 else 1651 ok = key_sign(private, &signature, &slen, 1652 buffer_ptr(&b), buffer_len(&b)); 1653 key_free(private); 1654 buffer_free(&b); 1655 if (ok != 0) { 1656 error("key_sign failed"); 1657 xfree(chost); 1658 xfree(pkalg); 1659 xfree(blob); 1660 return 0; 1661 } 1662 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1663 packet_put_cstring(authctxt->server_user); 1664 packet_put_cstring(authctxt->service); 1665 packet_put_cstring(authctxt->method->name); 1666 packet_put_cstring(pkalg); 1667 packet_put_string(blob, blen); 1668 packet_put_cstring(chost); 1669 packet_put_cstring(authctxt->local_user); 1670 packet_put_string(signature, slen); 1671 memset(signature, 's', slen); 1672 xfree(signature); 1673 xfree(chost); 1674 xfree(pkalg); 1675 xfree(blob); 1676 1677 packet_send(); 1678 return 1; 1679} 1680 1681#ifdef JPAKE 1682int 1683userauth_jpake(Authctxt *authctxt) 1684{ 1685 struct jpake_ctx *pctx; 1686 u_char *x1_proof, *x2_proof; 1687 u_int x1_proof_len, x2_proof_len; 1688 static int attempt = 0; /* XXX share with userauth_password's? */ 1689 1690 if (attempt++ >= options.number_of_password_prompts) 1691 return 0; 1692 if (attempt != 1) 1693 error("Permission denied, please try again."); 1694 1695 if (authctxt->methoddata != NULL) 1696 fatal("%s: authctxt->methoddata already set (%p)", 1697 __func__, authctxt->methoddata); 1698 1699 authctxt->methoddata = pctx = jpake_new(); 1700 1701 /* 1702 * Send request immediately, to get the protocol going while 1703 * we do the initial computations. 1704 */ 1705 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1706 packet_put_cstring(authctxt->server_user); 1707 packet_put_cstring(authctxt->service); 1708 packet_put_cstring(authctxt->method->name); 1709 packet_send(); 1710 packet_write_wait(); 1711 1712 jpake_step1(pctx->grp, 1713 &pctx->client_id, &pctx->client_id_len, 1714 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1715 &x1_proof, &x1_proof_len, 1716 &x2_proof, &x2_proof_len); 1717 1718 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1719 1720 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1721 packet_put_string(pctx->client_id, pctx->client_id_len); 1722 packet_put_bignum2(pctx->g_x1); 1723 packet_put_bignum2(pctx->g_x2); 1724 packet_put_string(x1_proof, x1_proof_len); 1725 packet_put_string(x2_proof, x2_proof_len); 1726 packet_send(); 1727 1728 bzero(x1_proof, x1_proof_len); 1729 bzero(x2_proof, x2_proof_len); 1730 xfree(x1_proof); 1731 xfree(x2_proof); 1732 1733 /* Expect step 1 packet from peer */ 1734 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1735 input_userauth_jpake_server_step1); 1736 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1737 &input_userauth_success_unexpected); 1738 1739 return 1; 1740} 1741 1742void 1743userauth_jpake_cleanup(Authctxt *authctxt) 1744{ 1745 debug3("%s: clean up", __func__); 1746 if (authctxt->methoddata != NULL) { 1747 jpake_free(authctxt->methoddata); 1748 authctxt->methoddata = NULL; 1749 } 1750 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1751} 1752#endif /* JPAKE */ 1753 1754/* find auth method */ 1755 1756/* 1757 * given auth method name, if configurable options permit this method fill 1758 * in auth_ident field and return true, otherwise return false. 1759 */ 1760static int 1761authmethod_is_enabled(Authmethod *method) 1762{ 1763 if (method == NULL) 1764 return 0; 1765 /* return false if options indicate this method is disabled */ 1766 if (method->enabled == NULL || *method->enabled == 0) 1767 return 0; 1768 /* return false if batch mode is enabled but method needs interactive mode */ 1769 if (method->batch_flag != NULL && *method->batch_flag != 0) 1770 return 0; 1771 return 1; 1772} 1773 1774static Authmethod * 1775authmethod_lookup(const char *name) 1776{ 1777 Authmethod *method = NULL; 1778 if (name != NULL) 1779 for (method = authmethods; method->name != NULL; method++) 1780 if (strcmp(name, method->name) == 0) 1781 return method; 1782 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1783 return NULL; 1784} 1785 1786/* XXX internal state */ 1787static Authmethod *current = NULL; 1788static char *supported = NULL; 1789static char *preferred = NULL; 1790 1791/* 1792 * Given the authentication method list sent by the server, return the 1793 * next method we should try. If the server initially sends a nil list, 1794 * use a built-in default list. 1795 */ 1796static Authmethod * 1797authmethod_get(char *authlist) 1798{ 1799 char *name = NULL; 1800 u_int next; 1801 1802 /* Use a suitable default if we're passed a nil list. */ 1803 if (authlist == NULL || strlen(authlist) == 0) 1804 authlist = options.preferred_authentications; 1805 1806 if (supported == NULL || strcmp(authlist, supported) != 0) { 1807 debug3("start over, passed a different list %s", authlist); 1808 if (supported != NULL) 1809 xfree(supported); 1810 supported = xstrdup(authlist); 1811 preferred = options.preferred_authentications; 1812 debug3("preferred %s", preferred); 1813 current = NULL; 1814 } else if (current != NULL && authmethod_is_enabled(current)) 1815 return current; 1816 1817 for (;;) { 1818 if ((name = match_list(preferred, supported, &next)) == NULL) { 1819 debug("No more authentication methods to try."); 1820 current = NULL; 1821 return NULL; 1822 } 1823 preferred += next; 1824 debug3("authmethod_lookup %s", name); 1825 debug3("remaining preferred: %s", preferred); 1826 if ((current = authmethod_lookup(name)) != NULL && 1827 authmethod_is_enabled(current)) { 1828 debug3("authmethod_is_enabled %s", name); 1829 debug("Next authentication method: %s", name); 1830 return current; 1831 } 1832 } 1833} 1834 1835static char * 1836authmethods_get(void) 1837{ 1838 Authmethod *method = NULL; 1839 Buffer b; 1840 char *list; 1841 1842 buffer_init(&b); 1843 for (method = authmethods; method->name != NULL; method++) { 1844 if (authmethod_is_enabled(method)) { 1845 if (buffer_len(&b) > 0) 1846 buffer_append(&b, ",", 1); 1847 buffer_append(&b, method->name, strlen(method->name)); 1848 } 1849 } 1850 buffer_append(&b, "\0", 1); 1851 list = xstrdup(buffer_ptr(&b)); 1852 buffer_free(&b); 1853 return list; 1854} 1855 1856