sshconnect2.c revision 197679
1/* $OpenBSD: sshconnect2.c,v 1.171 2009/03/05 07:18:19 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 <netdb.h> 36#include <pwd.h> 37#include <signal.h> 38#include <stdarg.h> 39#include <stdio.h> 40#include <string.h> 41#include <unistd.h> 42#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) 43#include <vis.h> 44#endif 45 46#include "openbsd-compat/sys-queue.h" 47 48#include "xmalloc.h" 49#include "ssh.h" 50#include "ssh2.h" 51#include "buffer.h" 52#include "packet.h" 53#include "compat.h" 54#include "cipher.h" 55#include "key.h" 56#include "kex.h" 57#include "myproposal.h" 58#include "sshconnect.h" 59#include "authfile.h" 60#include "dh.h" 61#include "authfd.h" 62#include "log.h" 63#include "readconf.h" 64#include "misc.h" 65#include "match.h" 66#include "dispatch.h" 67#include "canohost.h" 68#include "msg.h" 69#include "pathnames.h" 70#include "uidswap.h" 71#include "schnorr.h" 72#include "jpake.h" 73 74#ifdef GSSAPI 75#include "ssh-gss.h" 76#endif 77 78/* import */ 79extern char *client_version_string; 80extern char *server_version_string; 81extern Options options; 82 83/* 84 * SSH2 key exchange 85 */ 86 87u_char *session_id2 = NULL; 88u_int session_id2_len = 0; 89 90char *xxx_host; 91struct sockaddr *xxx_hostaddr; 92 93Kex *xxx_kex = NULL; 94 95static int 96verify_host_key_callback(Key *hostkey) 97{ 98 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 99 fatal("Host key verification failed."); 100 return 0; 101} 102 103void 104ssh_kex2(char *host, struct sockaddr *hostaddr) 105{ 106 Kex *kex; 107 108 xxx_host = host; 109 xxx_hostaddr = hostaddr; 110 111 if (options.ciphers == (char *)-1) { 112 logit("No valid ciphers for protocol version 2 given, using defaults."); 113 options.ciphers = NULL; 114 } 115 if (options.ciphers != NULL) { 116 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 117 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 118 } 119 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 120 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 121 myproposal[PROPOSAL_ENC_ALGS_STOC] = 122 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 123 if (options.compression) { 124 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 125 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 126 } else { 127 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 128 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 129 } 130 if (options.macs != NULL) { 131 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 132 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 133 } 134 if (options.hostkeyalgorithms != NULL) 135 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 136 options.hostkeyalgorithms; 137 138 if (options.rekey_limit) 139 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 140 141 /* start key exchange */ 142 kex = kex_setup(myproposal); 143 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 144 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 145 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 146 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 147 kex->client_version_string=client_version_string; 148 kex->server_version_string=server_version_string; 149 kex->verify_host_key=&verify_host_key_callback; 150 151 xxx_kex = kex; 152 153 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 154 155 session_id2 = kex->session_id; 156 session_id2_len = kex->session_id_len; 157 158#ifdef DEBUG_KEXDH 159 /* send 1st encrypted/maced/compressed message */ 160 packet_start(SSH2_MSG_IGNORE); 161 packet_put_cstring("markus"); 162 packet_send(); 163 packet_write_wait(); 164#endif 165} 166 167/* 168 * Authenticate user 169 */ 170 171typedef struct Authctxt Authctxt; 172typedef struct Authmethod Authmethod; 173typedef struct identity Identity; 174typedef struct idlist Idlist; 175 176struct identity { 177 TAILQ_ENTRY(identity) next; 178 AuthenticationConnection *ac; /* set if agent supports key */ 179 Key *key; /* public/private key */ 180 char *filename; /* comment for agent-only keys */ 181 int tried; 182 int isprivate; /* key points to the private key */ 183}; 184TAILQ_HEAD(idlist, identity); 185 186struct Authctxt { 187 const char *server_user; 188 const char *local_user; 189 const char *host; 190 const char *service; 191 Authmethod *method; 192 int success; 193 char *authlist; 194 /* pubkey */ 195 Idlist keys; 196 AuthenticationConnection *agent; 197 /* hostbased */ 198 Sensitive *sensitive; 199 /* kbd-interactive */ 200 int info_req_seen; 201 /* generic */ 202 void *methoddata; 203}; 204struct Authmethod { 205 char *name; /* string to compare against server's list */ 206 int (*userauth)(Authctxt *authctxt); 207 void (*cleanup)(Authctxt *authctxt); 208 int *enabled; /* flag in option struct that enables method */ 209 int *batch_flag; /* flag in option struct that disables method */ 210}; 211 212void input_userauth_success(int, u_int32_t, void *); 213void input_userauth_failure(int, u_int32_t, void *); 214void input_userauth_banner(int, u_int32_t, void *); 215void input_userauth_error(int, u_int32_t, void *); 216void input_userauth_info_req(int, u_int32_t, void *); 217void input_userauth_pk_ok(int, u_int32_t, void *); 218void input_userauth_passwd_changereq(int, u_int32_t, void *); 219void input_userauth_jpake_server_step1(int, u_int32_t, void *); 220void input_userauth_jpake_server_step2(int, u_int32_t, void *); 221void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 222 223int userauth_none(Authctxt *); 224int userauth_pubkey(Authctxt *); 225int userauth_passwd(Authctxt *); 226int userauth_kbdint(Authctxt *); 227int userauth_hostbased(Authctxt *); 228int userauth_jpake(Authctxt *); 229 230void userauth_jpake_cleanup(Authctxt *); 231 232#ifdef GSSAPI 233int userauth_gssapi(Authctxt *authctxt); 234void input_gssapi_response(int type, u_int32_t, void *); 235void input_gssapi_token(int type, u_int32_t, void *); 236void input_gssapi_hash(int type, u_int32_t, void *); 237void input_gssapi_error(int, u_int32_t, void *); 238void input_gssapi_errtok(int, u_int32_t, void *); 239#endif 240 241void userauth(Authctxt *, char *); 242 243static int sign_and_send_pubkey(Authctxt *, Identity *); 244static void pubkey_prepare(Authctxt *); 245static void pubkey_cleanup(Authctxt *); 246static Key *load_identity_file(char *); 247 248static Authmethod *authmethod_get(char *authlist); 249static Authmethod *authmethod_lookup(const char *name); 250static char *authmethods_get(void); 251 252Authmethod authmethods[] = { 253#ifdef GSSAPI 254 {"gssapi-with-mic", 255 userauth_gssapi, 256 NULL, 257 &options.gss_authentication, 258 NULL}, 259#endif 260 {"hostbased", 261 userauth_hostbased, 262 NULL, 263 &options.hostbased_authentication, 264 NULL}, 265 {"publickey", 266 userauth_pubkey, 267 NULL, 268 &options.pubkey_authentication, 269 NULL}, 270#ifdef JPAKE 271 {"jpake-01@openssh.com", 272 userauth_jpake, 273 userauth_jpake_cleanup, 274 &options.zero_knowledge_password_authentication, 275 &options.batch_mode}, 276#endif 277 {"keyboard-interactive", 278 userauth_kbdint, 279 NULL, 280 &options.kbd_interactive_authentication, 281 &options.batch_mode}, 282 {"password", 283 userauth_passwd, 284 NULL, 285 &options.password_authentication, 286 &options.batch_mode}, 287 {"none", 288 userauth_none, 289 NULL, 290 NULL, 291 NULL}, 292 {NULL, NULL, NULL, NULL, NULL} 293}; 294 295void 296ssh_userauth2(const char *local_user, const char *server_user, char *host, 297 Sensitive *sensitive) 298{ 299 Authctxt authctxt; 300 int type; 301 302 if (options.challenge_response_authentication) 303 options.kbd_interactive_authentication = 1; 304 305 packet_start(SSH2_MSG_SERVICE_REQUEST); 306 packet_put_cstring("ssh-userauth"); 307 packet_send(); 308 debug("SSH2_MSG_SERVICE_REQUEST sent"); 309 packet_write_wait(); 310 type = packet_read(); 311 if (type != SSH2_MSG_SERVICE_ACCEPT) 312 fatal("Server denied authentication request: %d", type); 313 if (packet_remaining() > 0) { 314 char *reply = packet_get_string(NULL); 315 debug2("service_accept: %s", reply); 316 xfree(reply); 317 } else { 318 debug2("buggy server: service_accept w/o service"); 319 } 320 packet_check_eom(); 321 debug("SSH2_MSG_SERVICE_ACCEPT received"); 322 323 if (options.preferred_authentications == NULL) 324 options.preferred_authentications = authmethods_get(); 325 326 /* setup authentication context */ 327 memset(&authctxt, 0, sizeof(authctxt)); 328 pubkey_prepare(&authctxt); 329 authctxt.server_user = server_user; 330 authctxt.local_user = local_user; 331 authctxt.host = host; 332 authctxt.service = "ssh-connection"; /* service name */ 333 authctxt.success = 0; 334 authctxt.method = authmethod_lookup("none"); 335 authctxt.authlist = NULL; 336 authctxt.methoddata = NULL; 337 authctxt.sensitive = sensitive; 338 authctxt.info_req_seen = 0; 339 if (authctxt.method == NULL) 340 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 341 342 /* initial userauth request */ 343 userauth_none(&authctxt); 344 345 dispatch_init(&input_userauth_error); 346 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 347 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 348 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 349 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 350 351 pubkey_cleanup(&authctxt); 352 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 353 354 debug("Authentication succeeded (%s).", authctxt.method->name); 355} 356 357void 358userauth(Authctxt *authctxt, char *authlist) 359{ 360 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 361 authctxt->method->cleanup(authctxt); 362 363 if (authctxt->methoddata) { 364 xfree(authctxt->methoddata); 365 authctxt->methoddata = NULL; 366 } 367 if (authlist == NULL) { 368 authlist = authctxt->authlist; 369 } else { 370 if (authctxt->authlist) 371 xfree(authctxt->authlist); 372 authctxt->authlist = authlist; 373 } 374 for (;;) { 375 Authmethod *method = authmethod_get(authlist); 376 if (method == NULL) 377 fatal("Permission denied (%s).", authlist); 378 authctxt->method = method; 379 380 /* reset the per method handler */ 381 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 382 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 383 384 /* and try new method */ 385 if (method->userauth(authctxt) != 0) { 386 debug2("we sent a %s packet, wait for reply", method->name); 387 break; 388 } else { 389 debug2("we did not send a packet, disable method"); 390 method->enabled = NULL; 391 } 392 } 393} 394 395/* ARGSUSED */ 396void 397input_userauth_error(int type, u_int32_t seq, void *ctxt) 398{ 399 fatal("input_userauth_error: bad message during authentication: " 400 "type %d", type); 401} 402 403/* ARGSUSED */ 404void 405input_userauth_banner(int type, u_int32_t seq, void *ctxt) 406{ 407 char *msg, *raw, *lang; 408 u_int len; 409 410 debug3("input_userauth_banner"); 411 raw = packet_get_string(&len); 412 lang = packet_get_string(NULL); 413 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 414 if (len > 65536) 415 len = 65536; 416 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 417 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL); 418 fprintf(stderr, "%s", msg); 419 xfree(msg); 420 } 421 xfree(raw); 422 xfree(lang); 423} 424 425/* ARGSUSED */ 426void 427input_userauth_success(int type, u_int32_t seq, void *ctxt) 428{ 429 Authctxt *authctxt = ctxt; 430 if (authctxt == NULL) 431 fatal("input_userauth_success: no authentication context"); 432 if (authctxt->authlist) { 433 xfree(authctxt->authlist); 434 authctxt->authlist = NULL; 435 } 436 if (authctxt->methoddata) { 437 xfree(authctxt->methoddata); 438 authctxt->methoddata = NULL; 439 } 440 authctxt->success = 1; /* break out */ 441} 442 443/* ARGSUSED */ 444void 445input_userauth_failure(int type, u_int32_t seq, void *ctxt) 446{ 447 Authctxt *authctxt = ctxt; 448 char *authlist = NULL; 449 int partial; 450 451 if (authctxt == NULL) 452 fatal("input_userauth_failure: no authentication context"); 453 454 authlist = packet_get_string(NULL); 455 partial = packet_get_char(); 456 packet_check_eom(); 457 458 if (partial != 0) 459 logit("Authenticated with partial success."); 460 debug("Authentications that can continue: %s", authlist); 461 462 userauth(authctxt, authlist); 463} 464 465/* ARGSUSED */ 466void 467input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 468{ 469 Authctxt *authctxt = ctxt; 470 Key *key = NULL; 471 Identity *id = NULL; 472 Buffer b; 473 int pktype, sent = 0; 474 u_int alen, blen; 475 char *pkalg, *fp; 476 u_char *pkblob; 477 478 if (authctxt == NULL) 479 fatal("input_userauth_pk_ok: no authentication context"); 480 if (datafellows & SSH_BUG_PKOK) { 481 /* this is similar to SSH_BUG_PKAUTH */ 482 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 483 pkblob = packet_get_string(&blen); 484 buffer_init(&b); 485 buffer_append(&b, pkblob, blen); 486 pkalg = buffer_get_string(&b, &alen); 487 buffer_free(&b); 488 } else { 489 pkalg = packet_get_string(&alen); 490 pkblob = packet_get_string(&blen); 491 } 492 packet_check_eom(); 493 494 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 495 496 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 497 debug("unknown pkalg %s", pkalg); 498 goto done; 499 } 500 if ((key = key_from_blob(pkblob, blen)) == NULL) { 501 debug("no key from blob. pkalg %s", pkalg); 502 goto done; 503 } 504 if (key->type != pktype) { 505 error("input_userauth_pk_ok: type mismatch " 506 "for decoded key (received %d, expected %d)", 507 key->type, pktype); 508 goto done; 509 } 510 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 511 debug2("input_userauth_pk_ok: fp %s", fp); 512 xfree(fp); 513 514 /* 515 * search keys in the reverse order, because last candidate has been 516 * moved to the end of the queue. this also avoids confusion by 517 * duplicate keys 518 */ 519 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 520 if (key_equal(key, id->key)) { 521 sent = sign_and_send_pubkey(authctxt, id); 522 break; 523 } 524 } 525done: 526 if (key != NULL) 527 key_free(key); 528 xfree(pkalg); 529 xfree(pkblob); 530 531 /* try another method if we did not send a packet */ 532 if (sent == 0) 533 userauth(authctxt, NULL); 534} 535 536#ifdef GSSAPI 537int 538userauth_gssapi(Authctxt *authctxt) 539{ 540 Gssctxt *gssctxt = NULL; 541 static gss_OID_set gss_supported = NULL; 542 static u_int mech = 0; 543 OM_uint32 min; 544 int ok = 0; 545 546 /* Try one GSSAPI method at a time, rather than sending them all at 547 * once. */ 548 549 if (gss_supported == NULL) 550 gss_indicate_mechs(&min, &gss_supported); 551 552 /* Check to see if the mechanism is usable before we offer it */ 553 while (mech < gss_supported->count && !ok) { 554 /* My DER encoding requires length<128 */ 555 if (gss_supported->elements[mech].length < 128 && 556 ssh_gssapi_check_mechanism(&gssctxt, 557 &gss_supported->elements[mech], authctxt->host)) { 558 ok = 1; /* Mechanism works */ 559 } else { 560 mech++; 561 } 562 } 563 564 if (!ok) 565 return 0; 566 567 authctxt->methoddata=(void *)gssctxt; 568 569 packet_start(SSH2_MSG_USERAUTH_REQUEST); 570 packet_put_cstring(authctxt->server_user); 571 packet_put_cstring(authctxt->service); 572 packet_put_cstring(authctxt->method->name); 573 574 packet_put_int(1); 575 576 packet_put_int((gss_supported->elements[mech].length) + 2); 577 packet_put_char(SSH_GSS_OIDTYPE); 578 packet_put_char(gss_supported->elements[mech].length); 579 packet_put_raw(gss_supported->elements[mech].elements, 580 gss_supported->elements[mech].length); 581 582 packet_send(); 583 584 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 585 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 586 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 587 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 588 589 mech++; /* Move along to next candidate */ 590 591 return 1; 592} 593 594static OM_uint32 595process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 596{ 597 Authctxt *authctxt = ctxt; 598 Gssctxt *gssctxt = authctxt->methoddata; 599 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 600 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 601 gss_buffer_desc gssbuf; 602 OM_uint32 status, ms, flags; 603 Buffer b; 604 605 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 606 recv_tok, &send_tok, &flags); 607 608 if (send_tok.length > 0) { 609 if (GSS_ERROR(status)) 610 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 611 else 612 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 613 614 packet_put_string(send_tok.value, send_tok.length); 615 packet_send(); 616 gss_release_buffer(&ms, &send_tok); 617 } 618 619 if (status == GSS_S_COMPLETE) { 620 /* send either complete or MIC, depending on mechanism */ 621 if (!(flags & GSS_C_INTEG_FLAG)) { 622 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 623 packet_send(); 624 } else { 625 ssh_gssapi_buildmic(&b, authctxt->server_user, 626 authctxt->service, "gssapi-with-mic"); 627 628 gssbuf.value = buffer_ptr(&b); 629 gssbuf.length = buffer_len(&b); 630 631 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 632 633 if (!GSS_ERROR(status)) { 634 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 635 packet_put_string(mic.value, mic.length); 636 637 packet_send(); 638 } 639 640 buffer_free(&b); 641 gss_release_buffer(&ms, &mic); 642 } 643 } 644 645 return status; 646} 647 648/* ARGSUSED */ 649void 650input_gssapi_response(int type, u_int32_t plen, void *ctxt) 651{ 652 Authctxt *authctxt = ctxt; 653 Gssctxt *gssctxt; 654 int oidlen; 655 char *oidv; 656 657 if (authctxt == NULL) 658 fatal("input_gssapi_response: no authentication context"); 659 gssctxt = authctxt->methoddata; 660 661 /* Setup our OID */ 662 oidv = packet_get_string(&oidlen); 663 664 if (oidlen <= 2 || 665 oidv[0] != SSH_GSS_OIDTYPE || 666 oidv[1] != oidlen - 2) { 667 xfree(oidv); 668 debug("Badly encoded mechanism OID received"); 669 userauth(authctxt, NULL); 670 return; 671 } 672 673 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 674 fatal("Server returned different OID than expected"); 675 676 packet_check_eom(); 677 678 xfree(oidv); 679 680 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 681 /* Start again with next method on list */ 682 debug("Trying to start again"); 683 userauth(authctxt, NULL); 684 return; 685 } 686} 687 688/* ARGSUSED */ 689void 690input_gssapi_token(int type, u_int32_t plen, void *ctxt) 691{ 692 Authctxt *authctxt = ctxt; 693 gss_buffer_desc recv_tok; 694 OM_uint32 status; 695 u_int slen; 696 697 if (authctxt == NULL) 698 fatal("input_gssapi_response: no authentication context"); 699 700 recv_tok.value = packet_get_string(&slen); 701 recv_tok.length = slen; /* safe typecast */ 702 703 packet_check_eom(); 704 705 status = process_gssapi_token(ctxt, &recv_tok); 706 707 xfree(recv_tok.value); 708 709 if (GSS_ERROR(status)) { 710 /* Start again with the next method in the list */ 711 userauth(authctxt, NULL); 712 return; 713 } 714} 715 716/* ARGSUSED */ 717void 718input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 719{ 720 Authctxt *authctxt = ctxt; 721 Gssctxt *gssctxt; 722 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 723 gss_buffer_desc recv_tok; 724 OM_uint32 status, ms; 725 u_int len; 726 727 if (authctxt == NULL) 728 fatal("input_gssapi_response: no authentication context"); 729 gssctxt = authctxt->methoddata; 730 731 recv_tok.value = packet_get_string(&len); 732 recv_tok.length = len; 733 734 packet_check_eom(); 735 736 /* Stick it into GSSAPI and see what it says */ 737 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 738 &recv_tok, &send_tok, NULL); 739 740 xfree(recv_tok.value); 741 gss_release_buffer(&ms, &send_tok); 742 743 /* Server will be returning a failed packet after this one */ 744} 745 746/* ARGSUSED */ 747void 748input_gssapi_error(int type, u_int32_t plen, void *ctxt) 749{ 750 OM_uint32 maj, min; 751 char *msg; 752 char *lang; 753 754 maj=packet_get_int(); 755 min=packet_get_int(); 756 msg=packet_get_string(NULL); 757 lang=packet_get_string(NULL); 758 759 packet_check_eom(); 760 761 debug("Server GSSAPI Error:\n%s", msg); 762 xfree(msg); 763 xfree(lang); 764} 765#endif /* GSSAPI */ 766 767int 768userauth_none(Authctxt *authctxt) 769{ 770 /* initial userauth request */ 771 packet_start(SSH2_MSG_USERAUTH_REQUEST); 772 packet_put_cstring(authctxt->server_user); 773 packet_put_cstring(authctxt->service); 774 packet_put_cstring(authctxt->method->name); 775 packet_send(); 776 return 1; 777} 778 779int 780userauth_passwd(Authctxt *authctxt) 781{ 782 static int attempt = 0; 783 char prompt[150]; 784 char *password; 785 786 if (attempt++ >= options.number_of_password_prompts) 787 return 0; 788 789 if (attempt != 1) 790 error("Permission denied, please try again."); 791 792 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 793 authctxt->server_user, authctxt->host); 794 password = read_passphrase(prompt, 0); 795 packet_start(SSH2_MSG_USERAUTH_REQUEST); 796 packet_put_cstring(authctxt->server_user); 797 packet_put_cstring(authctxt->service); 798 packet_put_cstring(authctxt->method->name); 799 packet_put_char(0); 800 packet_put_cstring(password); 801 memset(password, 0, strlen(password)); 802 xfree(password); 803 packet_add_padding(64); 804 packet_send(); 805 806 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 807 &input_userauth_passwd_changereq); 808 809 return 1; 810} 811 812/* 813 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 814 */ 815/* ARGSUSED */ 816void 817input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 818{ 819 Authctxt *authctxt = ctxt; 820 char *info, *lang, *password = NULL, *retype = NULL; 821 char prompt[150]; 822 823 debug2("input_userauth_passwd_changereq"); 824 825 if (authctxt == NULL) 826 fatal("input_userauth_passwd_changereq: " 827 "no authentication context"); 828 829 info = packet_get_string(NULL); 830 lang = packet_get_string(NULL); 831 if (strlen(info) > 0) 832 logit("%s", info); 833 xfree(info); 834 xfree(lang); 835 packet_start(SSH2_MSG_USERAUTH_REQUEST); 836 packet_put_cstring(authctxt->server_user); 837 packet_put_cstring(authctxt->service); 838 packet_put_cstring(authctxt->method->name); 839 packet_put_char(1); /* additional info */ 840 snprintf(prompt, sizeof(prompt), 841 "Enter %.30s@%.128s's old password: ", 842 authctxt->server_user, authctxt->host); 843 password = read_passphrase(prompt, 0); 844 packet_put_cstring(password); 845 memset(password, 0, strlen(password)); 846 xfree(password); 847 password = NULL; 848 while (password == NULL) { 849 snprintf(prompt, sizeof(prompt), 850 "Enter %.30s@%.128s's new password: ", 851 authctxt->server_user, authctxt->host); 852 password = read_passphrase(prompt, RP_ALLOW_EOF); 853 if (password == NULL) { 854 /* bail out */ 855 return; 856 } 857 snprintf(prompt, sizeof(prompt), 858 "Retype %.30s@%.128s's new password: ", 859 authctxt->server_user, authctxt->host); 860 retype = read_passphrase(prompt, 0); 861 if (strcmp(password, retype) != 0) { 862 memset(password, 0, strlen(password)); 863 xfree(password); 864 logit("Mismatch; try again, EOF to quit."); 865 password = NULL; 866 } 867 memset(retype, 0, strlen(retype)); 868 xfree(retype); 869 } 870 packet_put_cstring(password); 871 memset(password, 0, strlen(password)); 872 xfree(password); 873 packet_add_padding(64); 874 packet_send(); 875 876 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 877 &input_userauth_passwd_changereq); 878} 879 880#ifdef JPAKE 881static char * 882pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 883{ 884 /* OpenBSD crypt(3) handles all of these */ 885 if (strcmp(crypt_scheme, "crypt") == 0 || 886 strcmp(crypt_scheme, "bcrypt") == 0 || 887 strcmp(crypt_scheme, "md5crypt") == 0 || 888 strcmp(crypt_scheme, "crypt-extended") == 0) 889 return xstrdup(crypt(password, salt)); 890 error("%s: unsupported password encryption scheme \"%.100s\"", 891 __func__, crypt_scheme); 892 return NULL; 893} 894 895static BIGNUM * 896jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 897 const char *salt) 898{ 899 char prompt[256], *password, *crypted; 900 u_char *secret; 901 u_int secret_len; 902 BIGNUM *ret; 903 904 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 905 authctxt->server_user, authctxt->host); 906 password = read_passphrase(prompt, 0); 907 908 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 909 logit("Disabling %s authentication", authctxt->method->name); 910 authctxt->method->enabled = NULL; 911 /* Continue with an empty password to fail gracefully */ 912 crypted = xstrdup(""); 913 } 914 915#ifdef JPAKE_DEBUG 916 debug3("%s: salt = %s", __func__, salt); 917 debug3("%s: scheme = %s", __func__, crypt_scheme); 918 debug3("%s: crypted = %s", __func__, crypted); 919#endif 920 921 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 922 &secret, &secret_len) != 0) 923 fatal("%s: hash_buffer", __func__); 924 925 bzero(password, strlen(password)); 926 bzero(crypted, strlen(crypted)); 927 xfree(password); 928 xfree(crypted); 929 930 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 931 fatal("%s: BN_bin2bn (secret)", __func__); 932 bzero(secret, secret_len); 933 xfree(secret); 934 935 return ret; 936} 937 938/* ARGSUSED */ 939void 940input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 941{ 942 Authctxt *authctxt = ctxt; 943 struct jpake_ctx *pctx = authctxt->methoddata; 944 u_char *x3_proof, *x4_proof, *x2_s_proof; 945 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 946 char *crypt_scheme, *salt; 947 948 /* Disable this message */ 949 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 950 951 if ((pctx->g_x3 = BN_new()) == NULL || 952 (pctx->g_x4 = BN_new()) == NULL) 953 fatal("%s: BN_new", __func__); 954 955 /* Fetch step 1 values */ 956 crypt_scheme = packet_get_string(NULL); 957 salt = packet_get_string(NULL); 958 pctx->server_id = packet_get_string(&pctx->server_id_len); 959 packet_get_bignum2(pctx->g_x3); 960 packet_get_bignum2(pctx->g_x4); 961 x3_proof = packet_get_string(&x3_proof_len); 962 x4_proof = packet_get_string(&x4_proof_len); 963 packet_check_eom(); 964 965 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 966 967 /* Obtain password and derive secret */ 968 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 969 bzero(crypt_scheme, strlen(crypt_scheme)); 970 bzero(salt, strlen(salt)); 971 xfree(crypt_scheme); 972 xfree(salt); 973 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 974 975 /* Calculate step 2 values */ 976 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 977 pctx->g_x3, pctx->g_x4, pctx->x2, 978 pctx->server_id, pctx->server_id_len, 979 pctx->client_id, pctx->client_id_len, 980 x3_proof, x3_proof_len, 981 x4_proof, x4_proof_len, 982 &pctx->a, 983 &x2_s_proof, &x2_s_proof_len); 984 985 bzero(x3_proof, x3_proof_len); 986 bzero(x4_proof, x4_proof_len); 987 xfree(x3_proof); 988 xfree(x4_proof); 989 990 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 991 992 /* Send values for step 2 */ 993 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 994 packet_put_bignum2(pctx->a); 995 packet_put_string(x2_s_proof, x2_s_proof_len); 996 packet_send(); 997 998 bzero(x2_s_proof, x2_s_proof_len); 999 xfree(x2_s_proof); 1000 1001 /* Expect step 2 packet from peer */ 1002 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1003 input_userauth_jpake_server_step2); 1004} 1005 1006/* ARGSUSED */ 1007void 1008input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1009{ 1010 Authctxt *authctxt = ctxt; 1011 struct jpake_ctx *pctx = authctxt->methoddata; 1012 u_char *x4_s_proof; 1013 u_int x4_s_proof_len; 1014 1015 /* Disable this message */ 1016 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1017 1018 if ((pctx->b = BN_new()) == NULL) 1019 fatal("%s: BN_new", __func__); 1020 1021 /* Fetch step 2 values */ 1022 packet_get_bignum2(pctx->b); 1023 x4_s_proof = packet_get_string(&x4_s_proof_len); 1024 packet_check_eom(); 1025 1026 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1027 1028 /* Derive shared key and calculate confirmation hash */ 1029 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1030 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1031 pctx->client_id, pctx->client_id_len, 1032 pctx->server_id, pctx->server_id_len, 1033 session_id2, session_id2_len, 1034 x4_s_proof, x4_s_proof_len, 1035 &pctx->k, 1036 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1037 1038 bzero(x4_s_proof, x4_s_proof_len); 1039 xfree(x4_s_proof); 1040 1041 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1042 1043 /* Send key confirmation proof */ 1044 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1045 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1046 packet_send(); 1047 1048 /* Expect confirmation from peer */ 1049 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1050 input_userauth_jpake_server_confirm); 1051} 1052 1053/* ARGSUSED */ 1054void 1055input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1056{ 1057 Authctxt *authctxt = ctxt; 1058 struct jpake_ctx *pctx = authctxt->methoddata; 1059 1060 /* Disable this message */ 1061 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1062 1063 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1064 packet_check_eom(); 1065 1066 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1067 1068 /* Verify expected confirmation hash */ 1069 if (jpake_check_confirm(pctx->k, 1070 pctx->server_id, pctx->server_id_len, 1071 session_id2, session_id2_len, 1072 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1073 debug("%s: %s success", __func__, authctxt->method->name); 1074 else { 1075 debug("%s: confirmation mismatch", __func__); 1076 /* XXX stash this so if auth succeeds then we can warn/kill */ 1077 } 1078 1079 userauth_jpake_cleanup(authctxt); 1080} 1081#endif /* JPAKE */ 1082 1083static int 1084identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1085 u_char *data, u_int datalen) 1086{ 1087 Key *prv; 1088 int ret; 1089 1090 /* the agent supports this key */ 1091 if (id->ac) 1092 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1093 data, datalen)); 1094 /* 1095 * we have already loaded the private key or 1096 * the private key is stored in external hardware 1097 */ 1098 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1099 return (key_sign(id->key, sigp, lenp, data, datalen)); 1100 /* load the private key from the file */ 1101 if ((prv = load_identity_file(id->filename)) == NULL) 1102 return (-1); 1103 ret = key_sign(prv, sigp, lenp, data, datalen); 1104 key_free(prv); 1105 return (ret); 1106} 1107 1108static int 1109sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1110{ 1111 Buffer b; 1112 u_char *blob, *signature; 1113 u_int bloblen, slen; 1114 u_int skip = 0; 1115 int ret = -1; 1116 int have_sig = 1; 1117 1118 debug3("sign_and_send_pubkey"); 1119 1120 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1121 /* we cannot handle this key */ 1122 debug3("sign_and_send_pubkey: cannot handle key"); 1123 return 0; 1124 } 1125 /* data to be signed */ 1126 buffer_init(&b); 1127 if (datafellows & SSH_OLD_SESSIONID) { 1128 buffer_append(&b, session_id2, session_id2_len); 1129 skip = session_id2_len; 1130 } else { 1131 buffer_put_string(&b, session_id2, session_id2_len); 1132 skip = buffer_len(&b); 1133 } 1134 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1135 buffer_put_cstring(&b, authctxt->server_user); 1136 buffer_put_cstring(&b, 1137 datafellows & SSH_BUG_PKSERVICE ? 1138 "ssh-userauth" : 1139 authctxt->service); 1140 if (datafellows & SSH_BUG_PKAUTH) { 1141 buffer_put_char(&b, have_sig); 1142 } else { 1143 buffer_put_cstring(&b, authctxt->method->name); 1144 buffer_put_char(&b, have_sig); 1145 buffer_put_cstring(&b, key_ssh_name(id->key)); 1146 } 1147 buffer_put_string(&b, blob, bloblen); 1148 1149 /* generate signature */ 1150 ret = identity_sign(id, &signature, &slen, 1151 buffer_ptr(&b), buffer_len(&b)); 1152 if (ret == -1) { 1153 xfree(blob); 1154 buffer_free(&b); 1155 return 0; 1156 } 1157#ifdef DEBUG_PK 1158 buffer_dump(&b); 1159#endif 1160 if (datafellows & SSH_BUG_PKSERVICE) { 1161 buffer_clear(&b); 1162 buffer_append(&b, session_id2, session_id2_len); 1163 skip = session_id2_len; 1164 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1165 buffer_put_cstring(&b, authctxt->server_user); 1166 buffer_put_cstring(&b, authctxt->service); 1167 buffer_put_cstring(&b, authctxt->method->name); 1168 buffer_put_char(&b, have_sig); 1169 if (!(datafellows & SSH_BUG_PKAUTH)) 1170 buffer_put_cstring(&b, key_ssh_name(id->key)); 1171 buffer_put_string(&b, blob, bloblen); 1172 } 1173 xfree(blob); 1174 1175 /* append signature */ 1176 buffer_put_string(&b, signature, slen); 1177 xfree(signature); 1178 1179 /* skip session id and packet type */ 1180 if (buffer_len(&b) < skip + 1) 1181 fatal("userauth_pubkey: internal error"); 1182 buffer_consume(&b, skip + 1); 1183 1184 /* put remaining data from buffer into packet */ 1185 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1186 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1187 buffer_free(&b); 1188 packet_send(); 1189 1190 return 1; 1191} 1192 1193static int 1194send_pubkey_test(Authctxt *authctxt, Identity *id) 1195{ 1196 u_char *blob; 1197 u_int bloblen, have_sig = 0; 1198 1199 debug3("send_pubkey_test"); 1200 1201 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1202 /* we cannot handle this key */ 1203 debug3("send_pubkey_test: cannot handle key"); 1204 return 0; 1205 } 1206 /* register callback for USERAUTH_PK_OK message */ 1207 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1208 1209 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1210 packet_put_cstring(authctxt->server_user); 1211 packet_put_cstring(authctxt->service); 1212 packet_put_cstring(authctxt->method->name); 1213 packet_put_char(have_sig); 1214 if (!(datafellows & SSH_BUG_PKAUTH)) 1215 packet_put_cstring(key_ssh_name(id->key)); 1216 packet_put_string(blob, bloblen); 1217 xfree(blob); 1218 packet_send(); 1219 return 1; 1220} 1221 1222static Key * 1223load_identity_file(char *filename) 1224{ 1225 Key *private; 1226 char prompt[300], *passphrase; 1227 int perm_ok, quit, i; 1228 struct stat st; 1229 1230 if (stat(filename, &st) < 0) { 1231 debug3("no such identity: %s", filename); 1232 return NULL; 1233 } 1234 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1235 if (!perm_ok) 1236 return NULL; 1237 if (private == NULL) { 1238 if (options.batch_mode) 1239 return NULL; 1240 snprintf(prompt, sizeof prompt, 1241 "Enter passphrase for key '%.100s': ", filename); 1242 for (i = 0; i < options.number_of_password_prompts; i++) { 1243 passphrase = read_passphrase(prompt, 0); 1244 if (strcmp(passphrase, "") != 0) { 1245 private = key_load_private_type(KEY_UNSPEC, 1246 filename, passphrase, NULL, NULL); 1247 quit = 0; 1248 } else { 1249 debug2("no passphrase given, try next key"); 1250 quit = 1; 1251 } 1252 memset(passphrase, 0, strlen(passphrase)); 1253 xfree(passphrase); 1254 if (private != NULL || quit) 1255 break; 1256 debug2("bad passphrase given, try again..."); 1257 } 1258 } 1259 return private; 1260} 1261 1262/* 1263 * try keys in the following order: 1264 * 1. agent keys that are found in the config file 1265 * 2. other agent keys 1266 * 3. keys that are only listed in the config file 1267 */ 1268static void 1269pubkey_prepare(Authctxt *authctxt) 1270{ 1271 Identity *id; 1272 Idlist agent, files, *preferred; 1273 Key *key; 1274 AuthenticationConnection *ac; 1275 char *comment; 1276 int i, found; 1277 1278 TAILQ_INIT(&agent); /* keys from the agent */ 1279 TAILQ_INIT(&files); /* keys from the config file */ 1280 preferred = &authctxt->keys; 1281 TAILQ_INIT(preferred); /* preferred order of keys */ 1282 1283 /* list of keys stored in the filesystem */ 1284 for (i = 0; i < options.num_identity_files; i++) { 1285 key = options.identity_keys[i]; 1286 if (key && key->type == KEY_RSA1) 1287 continue; 1288 options.identity_keys[i] = NULL; 1289 id = xcalloc(1, sizeof(*id)); 1290 id->key = key; 1291 id->filename = xstrdup(options.identity_files[i]); 1292 TAILQ_INSERT_TAIL(&files, id, next); 1293 } 1294 /* list of keys supported by the agent */ 1295 if ((ac = ssh_get_authentication_connection())) { 1296 for (key = ssh_get_first_identity(ac, &comment, 2); 1297 key != NULL; 1298 key = ssh_get_next_identity(ac, &comment, 2)) { 1299 found = 0; 1300 TAILQ_FOREACH(id, &files, next) { 1301 /* agent keys from the config file are preferred */ 1302 if (key_equal(key, id->key)) { 1303 key_free(key); 1304 xfree(comment); 1305 TAILQ_REMOVE(&files, id, next); 1306 TAILQ_INSERT_TAIL(preferred, id, next); 1307 id->ac = ac; 1308 found = 1; 1309 break; 1310 } 1311 } 1312 if (!found && !options.identities_only) { 1313 id = xcalloc(1, sizeof(*id)); 1314 id->key = key; 1315 id->filename = comment; 1316 id->ac = ac; 1317 TAILQ_INSERT_TAIL(&agent, id, next); 1318 } 1319 } 1320 /* append remaining agent keys */ 1321 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1322 TAILQ_REMOVE(&agent, id, next); 1323 TAILQ_INSERT_TAIL(preferred, id, next); 1324 } 1325 authctxt->agent = ac; 1326 } 1327 /* append remaining keys from the config file */ 1328 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1329 TAILQ_REMOVE(&files, id, next); 1330 TAILQ_INSERT_TAIL(preferred, id, next); 1331 } 1332 TAILQ_FOREACH(id, preferred, next) { 1333 debug2("key: %s (%p)", id->filename, id->key); 1334 } 1335} 1336 1337static void 1338pubkey_cleanup(Authctxt *authctxt) 1339{ 1340 Identity *id; 1341 1342 if (authctxt->agent != NULL) 1343 ssh_close_authentication_connection(authctxt->agent); 1344 for (id = TAILQ_FIRST(&authctxt->keys); id; 1345 id = TAILQ_FIRST(&authctxt->keys)) { 1346 TAILQ_REMOVE(&authctxt->keys, id, next); 1347 if (id->key) 1348 key_free(id->key); 1349 if (id->filename) 1350 xfree(id->filename); 1351 xfree(id); 1352 } 1353} 1354 1355int 1356userauth_pubkey(Authctxt *authctxt) 1357{ 1358 Identity *id; 1359 int sent = 0; 1360 1361 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1362 if (id->tried++) 1363 return (0); 1364 /* move key to the end of the queue */ 1365 TAILQ_REMOVE(&authctxt->keys, id, next); 1366 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1367 /* 1368 * send a test message if we have the public key. for 1369 * encrypted keys we cannot do this and have to load the 1370 * private key instead 1371 */ 1372 if (id->key && id->key->type != KEY_RSA1) { 1373 debug("Offering public key: %s", id->filename); 1374 sent = send_pubkey_test(authctxt, id); 1375 } else if (id->key == NULL) { 1376 debug("Trying private key: %s", id->filename); 1377 id->key = load_identity_file(id->filename); 1378 if (id->key != NULL) { 1379 id->isprivate = 1; 1380 sent = sign_and_send_pubkey(authctxt, id); 1381 key_free(id->key); 1382 id->key = NULL; 1383 } 1384 } 1385 if (sent) 1386 return (sent); 1387 } 1388 return (0); 1389} 1390 1391/* 1392 * Send userauth request message specifying keyboard-interactive method. 1393 */ 1394int 1395userauth_kbdint(Authctxt *authctxt) 1396{ 1397 static int attempt = 0; 1398 1399 if (attempt++ >= options.number_of_password_prompts) 1400 return 0; 1401 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1402 if (attempt > 1 && !authctxt->info_req_seen) { 1403 debug3("userauth_kbdint: disable: no info_req_seen"); 1404 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1405 return 0; 1406 } 1407 1408 debug2("userauth_kbdint"); 1409 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1410 packet_put_cstring(authctxt->server_user); 1411 packet_put_cstring(authctxt->service); 1412 packet_put_cstring(authctxt->method->name); 1413 packet_put_cstring(""); /* lang */ 1414 packet_put_cstring(options.kbd_interactive_devices ? 1415 options.kbd_interactive_devices : ""); 1416 packet_send(); 1417 1418 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1419 return 1; 1420} 1421 1422/* 1423 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1424 */ 1425void 1426input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1427{ 1428 Authctxt *authctxt = ctxt; 1429 char *name, *inst, *lang, *prompt, *response; 1430 u_int num_prompts, i; 1431 int echo = 0; 1432 1433 debug2("input_userauth_info_req"); 1434 1435 if (authctxt == NULL) 1436 fatal("input_userauth_info_req: no authentication context"); 1437 1438 authctxt->info_req_seen = 1; 1439 1440 name = packet_get_string(NULL); 1441 inst = packet_get_string(NULL); 1442 lang = packet_get_string(NULL); 1443 if (strlen(name) > 0) 1444 logit("%s", name); 1445 if (strlen(inst) > 0) 1446 logit("%s", inst); 1447 xfree(name); 1448 xfree(inst); 1449 xfree(lang); 1450 1451 num_prompts = packet_get_int(); 1452 /* 1453 * Begin to build info response packet based on prompts requested. 1454 * We commit to providing the correct number of responses, so if 1455 * further on we run into a problem that prevents this, we have to 1456 * be sure and clean this up and send a correct error response. 1457 */ 1458 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1459 packet_put_int(num_prompts); 1460 1461 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1462 for (i = 0; i < num_prompts; i++) { 1463 prompt = packet_get_string(NULL); 1464 echo = packet_get_char(); 1465 1466 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1467 1468 packet_put_cstring(response); 1469 memset(response, 0, strlen(response)); 1470 xfree(response); 1471 xfree(prompt); 1472 } 1473 packet_check_eom(); /* done with parsing incoming message. */ 1474 1475 packet_add_padding(64); 1476 packet_send(); 1477} 1478 1479static int 1480ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1481 u_char *data, u_int datalen) 1482{ 1483 Buffer b; 1484 struct stat st; 1485 pid_t pid; 1486 int to[2], from[2], status, version = 2; 1487 1488 debug2("ssh_keysign called"); 1489 1490 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1491 error("ssh_keysign: no installed: %s", strerror(errno)); 1492 return -1; 1493 } 1494 if (fflush(stdout) != 0) 1495 error("ssh_keysign: fflush: %s", strerror(errno)); 1496 if (pipe(to) < 0) { 1497 error("ssh_keysign: pipe: %s", strerror(errno)); 1498 return -1; 1499 } 1500 if (pipe(from) < 0) { 1501 error("ssh_keysign: pipe: %s", strerror(errno)); 1502 return -1; 1503 } 1504 if ((pid = fork()) < 0) { 1505 error("ssh_keysign: fork: %s", strerror(errno)); 1506 return -1; 1507 } 1508 if (pid == 0) { 1509 permanently_drop_suid(getuid()); 1510 close(from[0]); 1511 if (dup2(from[1], STDOUT_FILENO) < 0) 1512 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1513 close(to[1]); 1514 if (dup2(to[0], STDIN_FILENO) < 0) 1515 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1516 close(from[1]); 1517 close(to[0]); 1518 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1519 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1520 strerror(errno)); 1521 } 1522 close(from[1]); 1523 close(to[0]); 1524 1525 buffer_init(&b); 1526 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1527 buffer_put_string(&b, data, datalen); 1528 if (ssh_msg_send(to[1], version, &b) == -1) 1529 fatal("ssh_keysign: couldn't send request"); 1530 1531 if (ssh_msg_recv(from[0], &b) < 0) { 1532 error("ssh_keysign: no reply"); 1533 buffer_free(&b); 1534 return -1; 1535 } 1536 close(from[0]); 1537 close(to[1]); 1538 1539 while (waitpid(pid, &status, 0) < 0) 1540 if (errno != EINTR) 1541 break; 1542 1543 if (buffer_get_char(&b) != version) { 1544 error("ssh_keysign: bad version"); 1545 buffer_free(&b); 1546 return -1; 1547 } 1548 *sigp = buffer_get_string(&b, lenp); 1549 buffer_free(&b); 1550 1551 return 0; 1552} 1553 1554int 1555userauth_hostbased(Authctxt *authctxt) 1556{ 1557 Key *private = NULL; 1558 Sensitive *sensitive = authctxt->sensitive; 1559 Buffer b; 1560 u_char *signature, *blob; 1561 char *chost, *pkalg, *p, myname[NI_MAXHOST]; 1562 const char *service; 1563 u_int blen, slen; 1564 int ok, i, len, found = 0; 1565 1566 /* check for a useful key */ 1567 for (i = 0; i < sensitive->nkeys; i++) { 1568 private = sensitive->keys[i]; 1569 if (private && private->type != KEY_RSA1) { 1570 found = 1; 1571 /* we take and free the key */ 1572 sensitive->keys[i] = NULL; 1573 break; 1574 } 1575 } 1576 if (!found) { 1577 debug("No more client hostkeys for hostbased authentication."); 1578 return 0; 1579 } 1580 if (key_to_blob(private, &blob, &blen) == 0) { 1581 key_free(private); 1582 return 0; 1583 } 1584 /* figure out a name for the client host */ 1585 p = NULL; 1586 if (packet_connection_is_on_socket()) 1587 p = get_local_name(packet_get_connection_in()); 1588 if (p == NULL) { 1589 if (gethostname(myname, sizeof(myname)) == -1) { 1590 verbose("userauth_hostbased: gethostname: %s", 1591 strerror(errno)); 1592 } else 1593 p = xstrdup(myname); 1594 } 1595 if (p == NULL) { 1596 error("userauth_hostbased: cannot get local ipaddr/name"); 1597 key_free(private); 1598 xfree(blob); 1599 return 0; 1600 } 1601 len = strlen(p) + 2; 1602 xasprintf(&chost, "%s.", p); 1603 debug2("userauth_hostbased: chost %s", chost); 1604 xfree(p); 1605 1606 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1607 authctxt->service; 1608 pkalg = xstrdup(key_ssh_name(private)); 1609 buffer_init(&b); 1610 /* construct data */ 1611 buffer_put_string(&b, session_id2, session_id2_len); 1612 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1613 buffer_put_cstring(&b, authctxt->server_user); 1614 buffer_put_cstring(&b, service); 1615 buffer_put_cstring(&b, authctxt->method->name); 1616 buffer_put_cstring(&b, pkalg); 1617 buffer_put_string(&b, blob, blen); 1618 buffer_put_cstring(&b, chost); 1619 buffer_put_cstring(&b, authctxt->local_user); 1620#ifdef DEBUG_PK 1621 buffer_dump(&b); 1622#endif 1623 if (sensitive->external_keysign) 1624 ok = ssh_keysign(private, &signature, &slen, 1625 buffer_ptr(&b), buffer_len(&b)); 1626 else 1627 ok = key_sign(private, &signature, &slen, 1628 buffer_ptr(&b), buffer_len(&b)); 1629 key_free(private); 1630 buffer_free(&b); 1631 if (ok != 0) { 1632 error("key_sign failed"); 1633 xfree(chost); 1634 xfree(pkalg); 1635 xfree(blob); 1636 return 0; 1637 } 1638 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1639 packet_put_cstring(authctxt->server_user); 1640 packet_put_cstring(authctxt->service); 1641 packet_put_cstring(authctxt->method->name); 1642 packet_put_cstring(pkalg); 1643 packet_put_string(blob, blen); 1644 packet_put_cstring(chost); 1645 packet_put_cstring(authctxt->local_user); 1646 packet_put_string(signature, slen); 1647 memset(signature, 's', slen); 1648 xfree(signature); 1649 xfree(chost); 1650 xfree(pkalg); 1651 xfree(blob); 1652 1653 packet_send(); 1654 return 1; 1655} 1656 1657#ifdef JPAKE 1658int 1659userauth_jpake(Authctxt *authctxt) 1660{ 1661 struct jpake_ctx *pctx; 1662 u_char *x1_proof, *x2_proof; 1663 u_int x1_proof_len, x2_proof_len; 1664 static int attempt = 0; /* XXX share with userauth_password's? */ 1665 1666 if (attempt++ >= options.number_of_password_prompts) 1667 return 0; 1668 if (attempt != 1) 1669 error("Permission denied, please try again."); 1670 1671 if (authctxt->methoddata != NULL) 1672 fatal("%s: authctxt->methoddata already set (%p)", 1673 __func__, authctxt->methoddata); 1674 1675 authctxt->methoddata = pctx = jpake_new(); 1676 1677 /* 1678 * Send request immediately, to get the protocol going while 1679 * we do the initial computations. 1680 */ 1681 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1682 packet_put_cstring(authctxt->server_user); 1683 packet_put_cstring(authctxt->service); 1684 packet_put_cstring(authctxt->method->name); 1685 packet_send(); 1686 packet_write_wait(); 1687 1688 jpake_step1(pctx->grp, 1689 &pctx->client_id, &pctx->client_id_len, 1690 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1691 &x1_proof, &x1_proof_len, 1692 &x2_proof, &x2_proof_len); 1693 1694 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1695 1696 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1697 packet_put_string(pctx->client_id, pctx->client_id_len); 1698 packet_put_bignum2(pctx->g_x1); 1699 packet_put_bignum2(pctx->g_x2); 1700 packet_put_string(x1_proof, x1_proof_len); 1701 packet_put_string(x2_proof, x2_proof_len); 1702 packet_send(); 1703 1704 bzero(x1_proof, x1_proof_len); 1705 bzero(x2_proof, x2_proof_len); 1706 xfree(x1_proof); 1707 xfree(x2_proof); 1708 1709 /* Expect step 1 packet from peer */ 1710 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1711 input_userauth_jpake_server_step1); 1712 1713 return 1; 1714} 1715 1716void 1717userauth_jpake_cleanup(Authctxt *authctxt) 1718{ 1719 debug3("%s: clean up", __func__); 1720 if (authctxt->methoddata != NULL) { 1721 jpake_free(authctxt->methoddata); 1722 authctxt->methoddata = NULL; 1723 } 1724} 1725#endif /* JPAKE */ 1726 1727/* find auth method */ 1728 1729/* 1730 * given auth method name, if configurable options permit this method fill 1731 * in auth_ident field and return true, otherwise return false. 1732 */ 1733static int 1734authmethod_is_enabled(Authmethod *method) 1735{ 1736 if (method == NULL) 1737 return 0; 1738 /* return false if options indicate this method is disabled */ 1739 if (method->enabled == NULL || *method->enabled == 0) 1740 return 0; 1741 /* return false if batch mode is enabled but method needs interactive mode */ 1742 if (method->batch_flag != NULL && *method->batch_flag != 0) 1743 return 0; 1744 return 1; 1745} 1746 1747static Authmethod * 1748authmethod_lookup(const char *name) 1749{ 1750 Authmethod *method = NULL; 1751 if (name != NULL) 1752 for (method = authmethods; method->name != NULL; method++) 1753 if (strcmp(name, method->name) == 0) 1754 return method; 1755 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1756 return NULL; 1757} 1758 1759/* XXX internal state */ 1760static Authmethod *current = NULL; 1761static char *supported = NULL; 1762static char *preferred = NULL; 1763 1764/* 1765 * Given the authentication method list sent by the server, return the 1766 * next method we should try. If the server initially sends a nil list, 1767 * use a built-in default list. 1768 */ 1769static Authmethod * 1770authmethod_get(char *authlist) 1771{ 1772 char *name = NULL; 1773 u_int next; 1774 1775 /* Use a suitable default if we're passed a nil list. */ 1776 if (authlist == NULL || strlen(authlist) == 0) 1777 authlist = options.preferred_authentications; 1778 1779 if (supported == NULL || strcmp(authlist, supported) != 0) { 1780 debug3("start over, passed a different list %s", authlist); 1781 if (supported != NULL) 1782 xfree(supported); 1783 supported = xstrdup(authlist); 1784 preferred = options.preferred_authentications; 1785 debug3("preferred %s", preferred); 1786 current = NULL; 1787 } else if (current != NULL && authmethod_is_enabled(current)) 1788 return current; 1789 1790 for (;;) { 1791 if ((name = match_list(preferred, supported, &next)) == NULL) { 1792 debug("No more authentication methods to try."); 1793 current = NULL; 1794 return NULL; 1795 } 1796 preferred += next; 1797 debug3("authmethod_lookup %s", name); 1798 debug3("remaining preferred: %s", preferred); 1799 if ((current = authmethod_lookup(name)) != NULL && 1800 authmethod_is_enabled(current)) { 1801 debug3("authmethod_is_enabled %s", name); 1802 debug("Next authentication method: %s", name); 1803 return current; 1804 } 1805 } 1806} 1807 1808static char * 1809authmethods_get(void) 1810{ 1811 Authmethod *method = NULL; 1812 Buffer b; 1813 char *list; 1814 1815 buffer_init(&b); 1816 for (method = authmethods; method->name != NULL; method++) { 1817 if (authmethod_is_enabled(method)) { 1818 if (buffer_len(&b) > 0) 1819 buffer_append(&b, ",", 1); 1820 buffer_append(&b, method->name, strlen(method->name)); 1821 } 1822 } 1823 buffer_append(&b, "\0", 1); 1824 list = xstrdup(buffer_ptr(&b)); 1825 buffer_free(&b); 1826 return list; 1827} 1828 1829