sshconnect2.c revision 221420
1/* $OpenBSD: sshconnect2.c,v 1.186 2010/11/29 23:45:51 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 "hostfile.h" 73#include "schnorr.h" 74#include "jpake.h" 75 76#ifdef GSSAPI 77#include "ssh-gss.h" 78#endif 79 80/* import */ 81extern char *client_version_string; 82extern char *server_version_string; 83extern Options options; 84 85/* 86 * SSH2 key exchange 87 */ 88 89u_char *session_id2 = NULL; 90u_int session_id2_len = 0; 91 92char *xxx_host; 93struct sockaddr *xxx_hostaddr; 94 95Kex *xxx_kex = NULL; 96 97static int 98verify_host_key_callback(Key *hostkey) 99{ 100 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 101 fatal("Host key verification failed."); 102 return 0; 103} 104 105static char * 106order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 107{ 108 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 109 size_t maxlen; 110 struct hostkeys *hostkeys; 111 int ktype; 112 113 /* Find all hostkeys for this hostname */ 114 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 115 hostkeys = init_hostkeys(); 116 load_hostkeys(hostkeys, hostname, options.user_hostfile2); 117 load_hostkeys(hostkeys, hostname, options.system_hostfile2); 118 load_hostkeys(hostkeys, hostname, options.user_hostfile); 119 load_hostkeys(hostkeys, hostname, options.system_hostfile); 120 121 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 122 maxlen = strlen(avail) + 1; 123 first = xmalloc(maxlen); 124 last = xmalloc(maxlen); 125 *first = *last = '\0'; 126 127#define ALG_APPEND(to, from) \ 128 do { \ 129 if (*to != '\0') \ 130 strlcat(to, ",", maxlen); \ 131 strlcat(to, from, maxlen); \ 132 } while (0) 133 134 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 135 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) 136 fatal("%s: unknown alg %s", __func__, alg); 137 if (lookup_key_in_hostkeys_by_type(hostkeys, 138 key_type_plain(ktype), NULL)) 139 ALG_APPEND(first, alg); 140 else 141 ALG_APPEND(last, alg); 142 } 143#undef ALG_APPEND 144 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); 145 if (*first != '\0') 146 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 147 148 xfree(first); 149 xfree(last); 150 xfree(hostname); 151 xfree(oavail); 152 free_hostkeys(hostkeys); 153 154 return ret; 155} 156 157void 158ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 159{ 160 Kex *kex; 161 162 xxx_host = host; 163 xxx_hostaddr = hostaddr; 164 165 if (options.ciphers == (char *)-1) { 166 logit("No valid ciphers for protocol version 2 given, using defaults."); 167 options.ciphers = NULL; 168 } 169 if (options.ciphers != NULL) { 170 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 171 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 172 } 173 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 174 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 175 myproposal[PROPOSAL_ENC_ALGS_STOC] = 176 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 177 if (options.compression) { 178 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 179 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 180 } else { 181 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 182 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 183 } 184 if (options.macs != NULL) { 185 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 186 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 187 } 188 if (options.hostkeyalgorithms != NULL) 189 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 190 options.hostkeyalgorithms; 191 else { 192 /* Prefer algorithms that we already have keys for */ 193 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 194 order_hostkeyalgs(host, hostaddr, port); 195 } 196 if (options.kex_algorithms != NULL) 197 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 198 199 if (options.rekey_limit) 200 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 201 202 /* start key exchange */ 203 kex = kex_setup(myproposal); 204 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 205 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 206 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 207 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 208 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 209 kex->client_version_string=client_version_string; 210 kex->server_version_string=server_version_string; 211 kex->verify_host_key=&verify_host_key_callback; 212 213 xxx_kex = kex; 214 215 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 216 217 if (options.use_roaming && !kex->roaming) { 218 debug("Roaming not allowed by server"); 219 options.use_roaming = 0; 220 } 221 222 session_id2 = kex->session_id; 223 session_id2_len = kex->session_id_len; 224 225#ifdef DEBUG_KEXDH 226 /* send 1st encrypted/maced/compressed message */ 227 packet_start(SSH2_MSG_IGNORE); 228 packet_put_cstring("markus"); 229 packet_send(); 230 packet_write_wait(); 231#endif 232} 233 234/* 235 * Authenticate user 236 */ 237 238typedef struct Authctxt Authctxt; 239typedef struct Authmethod Authmethod; 240typedef struct identity Identity; 241typedef struct idlist Idlist; 242 243struct identity { 244 TAILQ_ENTRY(identity) next; 245 AuthenticationConnection *ac; /* set if agent supports key */ 246 Key *key; /* public/private key */ 247 char *filename; /* comment for agent-only keys */ 248 int tried; 249 int isprivate; /* key points to the private key */ 250}; 251TAILQ_HEAD(idlist, identity); 252 253struct Authctxt { 254 const char *server_user; 255 const char *local_user; 256 const char *host; 257 const char *service; 258 Authmethod *method; 259 sig_atomic_t success; 260 char *authlist; 261 /* pubkey */ 262 Idlist keys; 263 AuthenticationConnection *agent; 264 /* hostbased */ 265 Sensitive *sensitive; 266 /* kbd-interactive */ 267 int info_req_seen; 268 /* generic */ 269 void *methoddata; 270}; 271struct Authmethod { 272 char *name; /* string to compare against server's list */ 273 int (*userauth)(Authctxt *authctxt); 274 void (*cleanup)(Authctxt *authctxt); 275 int *enabled; /* flag in option struct that enables method */ 276 int *batch_flag; /* flag in option struct that disables method */ 277}; 278 279void input_userauth_success(int, u_int32_t, void *); 280void input_userauth_success_unexpected(int, u_int32_t, void *); 281void input_userauth_failure(int, u_int32_t, void *); 282void input_userauth_banner(int, u_int32_t, void *); 283void input_userauth_error(int, u_int32_t, void *); 284void input_userauth_info_req(int, u_int32_t, void *); 285void input_userauth_pk_ok(int, u_int32_t, void *); 286void input_userauth_passwd_changereq(int, u_int32_t, void *); 287void input_userauth_jpake_server_step1(int, u_int32_t, void *); 288void input_userauth_jpake_server_step2(int, u_int32_t, void *); 289void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 290 291int userauth_none(Authctxt *); 292int userauth_pubkey(Authctxt *); 293int userauth_passwd(Authctxt *); 294int userauth_kbdint(Authctxt *); 295int userauth_hostbased(Authctxt *); 296int userauth_jpake(Authctxt *); 297 298void userauth_jpake_cleanup(Authctxt *); 299 300#ifdef GSSAPI 301int userauth_gssapi(Authctxt *authctxt); 302void input_gssapi_response(int type, u_int32_t, void *); 303void input_gssapi_token(int type, u_int32_t, void *); 304void input_gssapi_hash(int type, u_int32_t, void *); 305void input_gssapi_error(int, u_int32_t, void *); 306void input_gssapi_errtok(int, u_int32_t, void *); 307#endif 308 309void userauth(Authctxt *, char *); 310 311static int sign_and_send_pubkey(Authctxt *, Identity *); 312static void pubkey_prepare(Authctxt *); 313static void pubkey_cleanup(Authctxt *); 314static Key *load_identity_file(char *); 315 316static Authmethod *authmethod_get(char *authlist); 317static Authmethod *authmethod_lookup(const char *name); 318static char *authmethods_get(void); 319 320Authmethod authmethods[] = { 321#ifdef GSSAPI 322 {"gssapi-with-mic", 323 userauth_gssapi, 324 NULL, 325 &options.gss_authentication, 326 NULL}, 327#endif 328 {"hostbased", 329 userauth_hostbased, 330 NULL, 331 &options.hostbased_authentication, 332 NULL}, 333 {"publickey", 334 userauth_pubkey, 335 NULL, 336 &options.pubkey_authentication, 337 NULL}, 338#ifdef JPAKE 339 {"jpake-01@openssh.com", 340 userauth_jpake, 341 userauth_jpake_cleanup, 342 &options.zero_knowledge_password_authentication, 343 &options.batch_mode}, 344#endif 345 {"keyboard-interactive", 346 userauth_kbdint, 347 NULL, 348 &options.kbd_interactive_authentication, 349 &options.batch_mode}, 350 {"password", 351 userauth_passwd, 352 NULL, 353 &options.password_authentication, 354 &options.batch_mode}, 355 {"none", 356 userauth_none, 357 NULL, 358 NULL, 359 NULL}, 360 {NULL, NULL, NULL, NULL, NULL} 361}; 362 363void 364ssh_userauth2(const char *local_user, const char *server_user, char *host, 365 Sensitive *sensitive) 366{ 367 Authctxt authctxt; 368 int type; 369 370 if (options.challenge_response_authentication) 371 options.kbd_interactive_authentication = 1; 372 373 packet_start(SSH2_MSG_SERVICE_REQUEST); 374 packet_put_cstring("ssh-userauth"); 375 packet_send(); 376 debug("SSH2_MSG_SERVICE_REQUEST sent"); 377 packet_write_wait(); 378 type = packet_read(); 379 if (type != SSH2_MSG_SERVICE_ACCEPT) 380 fatal("Server denied authentication request: %d", type); 381 if (packet_remaining() > 0) { 382 char *reply = packet_get_string(NULL); 383 debug2("service_accept: %s", reply); 384 xfree(reply); 385 } else { 386 debug2("buggy server: service_accept w/o service"); 387 } 388 packet_check_eom(); 389 debug("SSH2_MSG_SERVICE_ACCEPT received"); 390 391 if (options.preferred_authentications == NULL) 392 options.preferred_authentications = authmethods_get(); 393 394 /* setup authentication context */ 395 memset(&authctxt, 0, sizeof(authctxt)); 396 pubkey_prepare(&authctxt); 397 authctxt.server_user = server_user; 398 authctxt.local_user = local_user; 399 authctxt.host = host; 400 authctxt.service = "ssh-connection"; /* service name */ 401 authctxt.success = 0; 402 authctxt.method = authmethod_lookup("none"); 403 authctxt.authlist = NULL; 404 authctxt.methoddata = NULL; 405 authctxt.sensitive = sensitive; 406 authctxt.info_req_seen = 0; 407 if (authctxt.method == NULL) 408 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 409 410 /* initial userauth request */ 411 userauth_none(&authctxt); 412 413 dispatch_init(&input_userauth_error); 414 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 415 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 416 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 417 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 418 419 pubkey_cleanup(&authctxt); 420 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 421 422 debug("Authentication succeeded (%s).", authctxt.method->name); 423} 424 425void 426userauth(Authctxt *authctxt, char *authlist) 427{ 428 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 429 authctxt->method->cleanup(authctxt); 430 431 if (authctxt->methoddata) { 432 xfree(authctxt->methoddata); 433 authctxt->methoddata = NULL; 434 } 435 if (authlist == NULL) { 436 authlist = authctxt->authlist; 437 } else { 438 if (authctxt->authlist) 439 xfree(authctxt->authlist); 440 authctxt->authlist = authlist; 441 } 442 for (;;) { 443 Authmethod *method = authmethod_get(authlist); 444 if (method == NULL) 445 fatal("Permission denied (%s).", authlist); 446 authctxt->method = method; 447 448 /* reset the per method handler */ 449 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 450 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 451 452 /* and try new method */ 453 if (method->userauth(authctxt) != 0) { 454 debug2("we sent a %s packet, wait for reply", method->name); 455 break; 456 } else { 457 debug2("we did not send a packet, disable method"); 458 method->enabled = NULL; 459 } 460 } 461} 462 463/* ARGSUSED */ 464void 465input_userauth_error(int type, u_int32_t seq, void *ctxt) 466{ 467 fatal("input_userauth_error: bad message during authentication: " 468 "type %d", type); 469} 470 471/* ARGSUSED */ 472void 473input_userauth_banner(int type, u_int32_t seq, void *ctxt) 474{ 475 char *msg, *raw, *lang; 476 u_int len; 477 478 debug3("input_userauth_banner"); 479 raw = packet_get_string(&len); 480 lang = packet_get_string(NULL); 481 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 482 if (len > 65536) 483 len = 65536; 484 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 485 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 486 fprintf(stderr, "%s", msg); 487 xfree(msg); 488 } 489 xfree(raw); 490 xfree(lang); 491} 492 493/* ARGSUSED */ 494void 495input_userauth_success(int type, u_int32_t seq, void *ctxt) 496{ 497 Authctxt *authctxt = ctxt; 498 499 if (authctxt == NULL) 500 fatal("input_userauth_success: no authentication context"); 501 if (authctxt->authlist) { 502 xfree(authctxt->authlist); 503 authctxt->authlist = NULL; 504 } 505 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 506 authctxt->method->cleanup(authctxt); 507 if (authctxt->methoddata) { 508 xfree(authctxt->methoddata); 509 authctxt->methoddata = NULL; 510 } 511 authctxt->success = 1; /* break out */ 512} 513 514void 515input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 516{ 517 Authctxt *authctxt = ctxt; 518 519 if (authctxt == NULL) 520 fatal("%s: no authentication context", __func__); 521 522 fatal("Unexpected authentication success during %s.", 523 authctxt->method->name); 524} 525 526/* ARGSUSED */ 527void 528input_userauth_failure(int type, u_int32_t seq, void *ctxt) 529{ 530 Authctxt *authctxt = ctxt; 531 char *authlist = NULL; 532 int partial; 533 534 if (authctxt == NULL) 535 fatal("input_userauth_failure: no authentication context"); 536 537 authlist = packet_get_string(NULL); 538 partial = packet_get_char(); 539 packet_check_eom(); 540 541 if (partial != 0) 542 logit("Authenticated with partial success."); 543 debug("Authentications that can continue: %s", authlist); 544 545 userauth(authctxt, authlist); 546} 547 548/* ARGSUSED */ 549void 550input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 551{ 552 Authctxt *authctxt = ctxt; 553 Key *key = NULL; 554 Identity *id = NULL; 555 Buffer b; 556 int pktype, sent = 0; 557 u_int alen, blen; 558 char *pkalg, *fp; 559 u_char *pkblob; 560 561 if (authctxt == NULL) 562 fatal("input_userauth_pk_ok: no authentication context"); 563 if (datafellows & SSH_BUG_PKOK) { 564 /* this is similar to SSH_BUG_PKAUTH */ 565 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 566 pkblob = packet_get_string(&blen); 567 buffer_init(&b); 568 buffer_append(&b, pkblob, blen); 569 pkalg = buffer_get_string(&b, &alen); 570 buffer_free(&b); 571 } else { 572 pkalg = packet_get_string(&alen); 573 pkblob = packet_get_string(&blen); 574 } 575 packet_check_eom(); 576 577 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 578 579 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 580 debug("unknown pkalg %s", pkalg); 581 goto done; 582 } 583 if ((key = key_from_blob(pkblob, blen)) == NULL) { 584 debug("no key from blob. pkalg %s", pkalg); 585 goto done; 586 } 587 if (key->type != pktype) { 588 error("input_userauth_pk_ok: type mismatch " 589 "for decoded key (received %d, expected %d)", 590 key->type, pktype); 591 goto done; 592 } 593 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 594 debug2("input_userauth_pk_ok: fp %s", fp); 595 xfree(fp); 596 597 /* 598 * search keys in the reverse order, because last candidate has been 599 * moved to the end of the queue. this also avoids confusion by 600 * duplicate keys 601 */ 602 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 603 if (key_equal(key, id->key)) { 604 sent = sign_and_send_pubkey(authctxt, id); 605 break; 606 } 607 } 608done: 609 if (key != NULL) 610 key_free(key); 611 xfree(pkalg); 612 xfree(pkblob); 613 614 /* try another method if we did not send a packet */ 615 if (sent == 0) 616 userauth(authctxt, NULL); 617} 618 619#ifdef GSSAPI 620int 621userauth_gssapi(Authctxt *authctxt) 622{ 623 Gssctxt *gssctxt = NULL; 624 static gss_OID_set gss_supported = NULL; 625 static u_int mech = 0; 626 OM_uint32 min; 627 int ok = 0; 628 629 /* Try one GSSAPI method at a time, rather than sending them all at 630 * once. */ 631 632 if (gss_supported == NULL) 633 gss_indicate_mechs(&min, &gss_supported); 634 635 /* Check to see if the mechanism is usable before we offer it */ 636 while (mech < gss_supported->count && !ok) { 637 /* My DER encoding requires length<128 */ 638 if (gss_supported->elements[mech].length < 128 && 639 ssh_gssapi_check_mechanism(&gssctxt, 640 &gss_supported->elements[mech], authctxt->host)) { 641 ok = 1; /* Mechanism works */ 642 } else { 643 mech++; 644 } 645 } 646 647 if (!ok) 648 return 0; 649 650 authctxt->methoddata=(void *)gssctxt; 651 652 packet_start(SSH2_MSG_USERAUTH_REQUEST); 653 packet_put_cstring(authctxt->server_user); 654 packet_put_cstring(authctxt->service); 655 packet_put_cstring(authctxt->method->name); 656 657 packet_put_int(1); 658 659 packet_put_int((gss_supported->elements[mech].length) + 2); 660 packet_put_char(SSH_GSS_OIDTYPE); 661 packet_put_char(gss_supported->elements[mech].length); 662 packet_put_raw(gss_supported->elements[mech].elements, 663 gss_supported->elements[mech].length); 664 665 packet_send(); 666 667 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 668 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 669 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 670 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 671 672 mech++; /* Move along to next candidate */ 673 674 return 1; 675} 676 677static OM_uint32 678process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 679{ 680 Authctxt *authctxt = ctxt; 681 Gssctxt *gssctxt = authctxt->methoddata; 682 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 683 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 684 gss_buffer_desc gssbuf; 685 OM_uint32 status, ms, flags; 686 Buffer b; 687 688 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 689 recv_tok, &send_tok, &flags); 690 691 if (send_tok.length > 0) { 692 if (GSS_ERROR(status)) 693 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 694 else 695 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 696 697 packet_put_string(send_tok.value, send_tok.length); 698 packet_send(); 699 gss_release_buffer(&ms, &send_tok); 700 } 701 702 if (status == GSS_S_COMPLETE) { 703 /* send either complete or MIC, depending on mechanism */ 704 if (!(flags & GSS_C_INTEG_FLAG)) { 705 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 706 packet_send(); 707 } else { 708 ssh_gssapi_buildmic(&b, authctxt->server_user, 709 authctxt->service, "gssapi-with-mic"); 710 711 gssbuf.value = buffer_ptr(&b); 712 gssbuf.length = buffer_len(&b); 713 714 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 715 716 if (!GSS_ERROR(status)) { 717 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 718 packet_put_string(mic.value, mic.length); 719 720 packet_send(); 721 } 722 723 buffer_free(&b); 724 gss_release_buffer(&ms, &mic); 725 } 726 } 727 728 return status; 729} 730 731/* ARGSUSED */ 732void 733input_gssapi_response(int type, u_int32_t plen, void *ctxt) 734{ 735 Authctxt *authctxt = ctxt; 736 Gssctxt *gssctxt; 737 int oidlen; 738 char *oidv; 739 740 if (authctxt == NULL) 741 fatal("input_gssapi_response: no authentication context"); 742 gssctxt = authctxt->methoddata; 743 744 /* Setup our OID */ 745 oidv = packet_get_string(&oidlen); 746 747 if (oidlen <= 2 || 748 oidv[0] != SSH_GSS_OIDTYPE || 749 oidv[1] != oidlen - 2) { 750 xfree(oidv); 751 debug("Badly encoded mechanism OID received"); 752 userauth(authctxt, NULL); 753 return; 754 } 755 756 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 757 fatal("Server returned different OID than expected"); 758 759 packet_check_eom(); 760 761 xfree(oidv); 762 763 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 764 /* Start again with next method on list */ 765 debug("Trying to start again"); 766 userauth(authctxt, NULL); 767 return; 768 } 769} 770 771/* ARGSUSED */ 772void 773input_gssapi_token(int type, u_int32_t plen, void *ctxt) 774{ 775 Authctxt *authctxt = ctxt; 776 gss_buffer_desc recv_tok; 777 OM_uint32 status; 778 u_int slen; 779 780 if (authctxt == NULL) 781 fatal("input_gssapi_response: no authentication context"); 782 783 recv_tok.value = packet_get_string(&slen); 784 recv_tok.length = slen; /* safe typecast */ 785 786 packet_check_eom(); 787 788 status = process_gssapi_token(ctxt, &recv_tok); 789 790 xfree(recv_tok.value); 791 792 if (GSS_ERROR(status)) { 793 /* Start again with the next method in the list */ 794 userauth(authctxt, NULL); 795 return; 796 } 797} 798 799/* ARGSUSED */ 800void 801input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 802{ 803 Authctxt *authctxt = ctxt; 804 Gssctxt *gssctxt; 805 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 806 gss_buffer_desc recv_tok; 807 OM_uint32 status, ms; 808 u_int len; 809 810 if (authctxt == NULL) 811 fatal("input_gssapi_response: no authentication context"); 812 gssctxt = authctxt->methoddata; 813 814 recv_tok.value = packet_get_string(&len); 815 recv_tok.length = len; 816 817 packet_check_eom(); 818 819 /* Stick it into GSSAPI and see what it says */ 820 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 821 &recv_tok, &send_tok, NULL); 822 823 xfree(recv_tok.value); 824 gss_release_buffer(&ms, &send_tok); 825 826 /* Server will be returning a failed packet after this one */ 827} 828 829/* ARGSUSED */ 830void 831input_gssapi_error(int type, u_int32_t plen, void *ctxt) 832{ 833 OM_uint32 maj, min; 834 char *msg; 835 char *lang; 836 837 maj=packet_get_int(); 838 min=packet_get_int(); 839 msg=packet_get_string(NULL); 840 lang=packet_get_string(NULL); 841 842 packet_check_eom(); 843 844 debug("Server GSSAPI Error:\n%s", msg); 845 xfree(msg); 846 xfree(lang); 847} 848#endif /* GSSAPI */ 849 850int 851userauth_none(Authctxt *authctxt) 852{ 853 /* initial userauth request */ 854 packet_start(SSH2_MSG_USERAUTH_REQUEST); 855 packet_put_cstring(authctxt->server_user); 856 packet_put_cstring(authctxt->service); 857 packet_put_cstring(authctxt->method->name); 858 packet_send(); 859 return 1; 860} 861 862int 863userauth_passwd(Authctxt *authctxt) 864{ 865 static int attempt = 0; 866 char prompt[150]; 867 char *password; 868 const char *host = options.host_key_alias ? options.host_key_alias : 869 authctxt->host; 870 871 if (attempt++ >= options.number_of_password_prompts) 872 return 0; 873 874 if (attempt != 1) 875 error("Permission denied, please try again."); 876 877 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 878 authctxt->server_user, host); 879 password = read_passphrase(prompt, 0); 880 packet_start(SSH2_MSG_USERAUTH_REQUEST); 881 packet_put_cstring(authctxt->server_user); 882 packet_put_cstring(authctxt->service); 883 packet_put_cstring(authctxt->method->name); 884 packet_put_char(0); 885 packet_put_cstring(password); 886 memset(password, 0, strlen(password)); 887 xfree(password); 888 packet_add_padding(64); 889 packet_send(); 890 891 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 892 &input_userauth_passwd_changereq); 893 894 return 1; 895} 896 897/* 898 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 899 */ 900/* ARGSUSED */ 901void 902input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 903{ 904 Authctxt *authctxt = ctxt; 905 char *info, *lang, *password = NULL, *retype = NULL; 906 char prompt[150]; 907 const char *host = options.host_key_alias ? options.host_key_alias : 908 authctxt->host; 909 910 debug2("input_userauth_passwd_changereq"); 911 912 if (authctxt == NULL) 913 fatal("input_userauth_passwd_changereq: " 914 "no authentication context"); 915 916 info = packet_get_string(NULL); 917 lang = packet_get_string(NULL); 918 if (strlen(info) > 0) 919 logit("%s", info); 920 xfree(info); 921 xfree(lang); 922 packet_start(SSH2_MSG_USERAUTH_REQUEST); 923 packet_put_cstring(authctxt->server_user); 924 packet_put_cstring(authctxt->service); 925 packet_put_cstring(authctxt->method->name); 926 packet_put_char(1); /* additional info */ 927 snprintf(prompt, sizeof(prompt), 928 "Enter %.30s@%.128s's old password: ", 929 authctxt->server_user, host); 930 password = read_passphrase(prompt, 0); 931 packet_put_cstring(password); 932 memset(password, 0, strlen(password)); 933 xfree(password); 934 password = NULL; 935 while (password == NULL) { 936 snprintf(prompt, sizeof(prompt), 937 "Enter %.30s@%.128s's new password: ", 938 authctxt->server_user, host); 939 password = read_passphrase(prompt, RP_ALLOW_EOF); 940 if (password == NULL) { 941 /* bail out */ 942 return; 943 } 944 snprintf(prompt, sizeof(prompt), 945 "Retype %.30s@%.128s's new password: ", 946 authctxt->server_user, host); 947 retype = read_passphrase(prompt, 0); 948 if (strcmp(password, retype) != 0) { 949 memset(password, 0, strlen(password)); 950 xfree(password); 951 logit("Mismatch; try again, EOF to quit."); 952 password = NULL; 953 } 954 memset(retype, 0, strlen(retype)); 955 xfree(retype); 956 } 957 packet_put_cstring(password); 958 memset(password, 0, strlen(password)); 959 xfree(password); 960 packet_add_padding(64); 961 packet_send(); 962 963 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 964 &input_userauth_passwd_changereq); 965} 966 967#ifdef JPAKE 968static char * 969pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 970{ 971 /* OpenBSD crypt(3) handles all of these */ 972 if (strcmp(crypt_scheme, "crypt") == 0 || 973 strcmp(crypt_scheme, "bcrypt") == 0 || 974 strcmp(crypt_scheme, "md5crypt") == 0 || 975 strcmp(crypt_scheme, "crypt-extended") == 0) 976 return xstrdup(crypt(password, salt)); 977 error("%s: unsupported password encryption scheme \"%.100s\"", 978 __func__, crypt_scheme); 979 return NULL; 980} 981 982static BIGNUM * 983jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 984 const char *salt) 985{ 986 char prompt[256], *password, *crypted; 987 u_char *secret; 988 u_int secret_len; 989 BIGNUM *ret; 990 991 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 992 authctxt->server_user, authctxt->host); 993 password = read_passphrase(prompt, 0); 994 995 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 996 logit("Disabling %s authentication", authctxt->method->name); 997 authctxt->method->enabled = NULL; 998 /* Continue with an empty password to fail gracefully */ 999 crypted = xstrdup(""); 1000 } 1001 1002#ifdef JPAKE_DEBUG 1003 debug3("%s: salt = %s", __func__, salt); 1004 debug3("%s: scheme = %s", __func__, crypt_scheme); 1005 debug3("%s: crypted = %s", __func__, crypted); 1006#endif 1007 1008 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 1009 &secret, &secret_len) != 0) 1010 fatal("%s: hash_buffer", __func__); 1011 1012 bzero(password, strlen(password)); 1013 bzero(crypted, strlen(crypted)); 1014 xfree(password); 1015 xfree(crypted); 1016 1017 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 1018 fatal("%s: BN_bin2bn (secret)", __func__); 1019 bzero(secret, secret_len); 1020 xfree(secret); 1021 1022 return ret; 1023} 1024 1025/* ARGSUSED */ 1026void 1027input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 1028{ 1029 Authctxt *authctxt = ctxt; 1030 struct jpake_ctx *pctx = authctxt->methoddata; 1031 u_char *x3_proof, *x4_proof, *x2_s_proof; 1032 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 1033 char *crypt_scheme, *salt; 1034 1035 /* Disable this message */ 1036 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 1037 1038 if ((pctx->g_x3 = BN_new()) == NULL || 1039 (pctx->g_x4 = BN_new()) == NULL) 1040 fatal("%s: BN_new", __func__); 1041 1042 /* Fetch step 1 values */ 1043 crypt_scheme = packet_get_string(NULL); 1044 salt = packet_get_string(NULL); 1045 pctx->server_id = packet_get_string(&pctx->server_id_len); 1046 packet_get_bignum2(pctx->g_x3); 1047 packet_get_bignum2(pctx->g_x4); 1048 x3_proof = packet_get_string(&x3_proof_len); 1049 x4_proof = packet_get_string(&x4_proof_len); 1050 packet_check_eom(); 1051 1052 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1053 1054 /* Obtain password and derive secret */ 1055 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1056 bzero(crypt_scheme, strlen(crypt_scheme)); 1057 bzero(salt, strlen(salt)); 1058 xfree(crypt_scheme); 1059 xfree(salt); 1060 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1061 1062 /* Calculate step 2 values */ 1063 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1064 pctx->g_x3, pctx->g_x4, pctx->x2, 1065 pctx->server_id, pctx->server_id_len, 1066 pctx->client_id, pctx->client_id_len, 1067 x3_proof, x3_proof_len, 1068 x4_proof, x4_proof_len, 1069 &pctx->a, 1070 &x2_s_proof, &x2_s_proof_len); 1071 1072 bzero(x3_proof, x3_proof_len); 1073 bzero(x4_proof, x4_proof_len); 1074 xfree(x3_proof); 1075 xfree(x4_proof); 1076 1077 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1078 1079 /* Send values for step 2 */ 1080 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1081 packet_put_bignum2(pctx->a); 1082 packet_put_string(x2_s_proof, x2_s_proof_len); 1083 packet_send(); 1084 1085 bzero(x2_s_proof, x2_s_proof_len); 1086 xfree(x2_s_proof); 1087 1088 /* Expect step 2 packet from peer */ 1089 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1090 input_userauth_jpake_server_step2); 1091} 1092 1093/* ARGSUSED */ 1094void 1095input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1096{ 1097 Authctxt *authctxt = ctxt; 1098 struct jpake_ctx *pctx = authctxt->methoddata; 1099 u_char *x4_s_proof; 1100 u_int x4_s_proof_len; 1101 1102 /* Disable this message */ 1103 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1104 1105 if ((pctx->b = BN_new()) == NULL) 1106 fatal("%s: BN_new", __func__); 1107 1108 /* Fetch step 2 values */ 1109 packet_get_bignum2(pctx->b); 1110 x4_s_proof = packet_get_string(&x4_s_proof_len); 1111 packet_check_eom(); 1112 1113 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1114 1115 /* Derive shared key and calculate confirmation hash */ 1116 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1117 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1118 pctx->client_id, pctx->client_id_len, 1119 pctx->server_id, pctx->server_id_len, 1120 session_id2, session_id2_len, 1121 x4_s_proof, x4_s_proof_len, 1122 &pctx->k, 1123 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1124 1125 bzero(x4_s_proof, x4_s_proof_len); 1126 xfree(x4_s_proof); 1127 1128 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1129 1130 /* Send key confirmation proof */ 1131 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1132 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1133 packet_send(); 1134 1135 /* Expect confirmation from peer */ 1136 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1137 input_userauth_jpake_server_confirm); 1138} 1139 1140/* ARGSUSED */ 1141void 1142input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1143{ 1144 Authctxt *authctxt = ctxt; 1145 struct jpake_ctx *pctx = authctxt->methoddata; 1146 1147 /* Disable this message */ 1148 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1149 1150 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1151 packet_check_eom(); 1152 1153 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1154 1155 /* Verify expected confirmation hash */ 1156 if (jpake_check_confirm(pctx->k, 1157 pctx->server_id, pctx->server_id_len, 1158 session_id2, session_id2_len, 1159 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1160 debug("%s: %s success", __func__, authctxt->method->name); 1161 else { 1162 debug("%s: confirmation mismatch", __func__); 1163 /* XXX stash this so if auth succeeds then we can warn/kill */ 1164 } 1165 1166 userauth_jpake_cleanup(authctxt); 1167} 1168#endif /* JPAKE */ 1169 1170static int 1171identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1172 u_char *data, u_int datalen) 1173{ 1174 Key *prv; 1175 int ret; 1176 1177 /* the agent supports this key */ 1178 if (id->ac) 1179 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1180 data, datalen)); 1181 /* 1182 * we have already loaded the private key or 1183 * the private key is stored in external hardware 1184 */ 1185 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1186 return (key_sign(id->key, sigp, lenp, data, datalen)); 1187 /* load the private key from the file */ 1188 if ((prv = load_identity_file(id->filename)) == NULL) 1189 return (-1); 1190 ret = key_sign(prv, sigp, lenp, data, datalen); 1191 key_free(prv); 1192 return (ret); 1193} 1194 1195static int 1196sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1197{ 1198 Buffer b; 1199 u_char *blob, *signature; 1200 u_int bloblen, slen; 1201 u_int skip = 0; 1202 int ret = -1; 1203 int have_sig = 1; 1204 char *fp; 1205 1206 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1207 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1208 xfree(fp); 1209 1210 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1211 /* we cannot handle this key */ 1212 debug3("sign_and_send_pubkey: cannot handle key"); 1213 return 0; 1214 } 1215 /* data to be signed */ 1216 buffer_init(&b); 1217 if (datafellows & SSH_OLD_SESSIONID) { 1218 buffer_append(&b, session_id2, session_id2_len); 1219 skip = session_id2_len; 1220 } else { 1221 buffer_put_string(&b, session_id2, session_id2_len); 1222 skip = buffer_len(&b); 1223 } 1224 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1225 buffer_put_cstring(&b, authctxt->server_user); 1226 buffer_put_cstring(&b, 1227 datafellows & SSH_BUG_PKSERVICE ? 1228 "ssh-userauth" : 1229 authctxt->service); 1230 if (datafellows & SSH_BUG_PKAUTH) { 1231 buffer_put_char(&b, have_sig); 1232 } else { 1233 buffer_put_cstring(&b, authctxt->method->name); 1234 buffer_put_char(&b, have_sig); 1235 buffer_put_cstring(&b, key_ssh_name(id->key)); 1236 } 1237 buffer_put_string(&b, blob, bloblen); 1238 1239 /* generate signature */ 1240 ret = identity_sign(id, &signature, &slen, 1241 buffer_ptr(&b), buffer_len(&b)); 1242 if (ret == -1) { 1243 xfree(blob); 1244 buffer_free(&b); 1245 return 0; 1246 } 1247#ifdef DEBUG_PK 1248 buffer_dump(&b); 1249#endif 1250 if (datafellows & SSH_BUG_PKSERVICE) { 1251 buffer_clear(&b); 1252 buffer_append(&b, session_id2, session_id2_len); 1253 skip = session_id2_len; 1254 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1255 buffer_put_cstring(&b, authctxt->server_user); 1256 buffer_put_cstring(&b, authctxt->service); 1257 buffer_put_cstring(&b, authctxt->method->name); 1258 buffer_put_char(&b, have_sig); 1259 if (!(datafellows & SSH_BUG_PKAUTH)) 1260 buffer_put_cstring(&b, key_ssh_name(id->key)); 1261 buffer_put_string(&b, blob, bloblen); 1262 } 1263 xfree(blob); 1264 1265 /* append signature */ 1266 buffer_put_string(&b, signature, slen); 1267 xfree(signature); 1268 1269 /* skip session id and packet type */ 1270 if (buffer_len(&b) < skip + 1) 1271 fatal("userauth_pubkey: internal error"); 1272 buffer_consume(&b, skip + 1); 1273 1274 /* put remaining data from buffer into packet */ 1275 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1276 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1277 buffer_free(&b); 1278 packet_send(); 1279 1280 return 1; 1281} 1282 1283static int 1284send_pubkey_test(Authctxt *authctxt, Identity *id) 1285{ 1286 u_char *blob; 1287 u_int bloblen, have_sig = 0; 1288 1289 debug3("send_pubkey_test"); 1290 1291 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1292 /* we cannot handle this key */ 1293 debug3("send_pubkey_test: cannot handle key"); 1294 return 0; 1295 } 1296 /* register callback for USERAUTH_PK_OK message */ 1297 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1298 1299 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1300 packet_put_cstring(authctxt->server_user); 1301 packet_put_cstring(authctxt->service); 1302 packet_put_cstring(authctxt->method->name); 1303 packet_put_char(have_sig); 1304 if (!(datafellows & SSH_BUG_PKAUTH)) 1305 packet_put_cstring(key_ssh_name(id->key)); 1306 packet_put_string(blob, bloblen); 1307 xfree(blob); 1308 packet_send(); 1309 return 1; 1310} 1311 1312static Key * 1313load_identity_file(char *filename) 1314{ 1315 Key *private; 1316 char prompt[300], *passphrase; 1317 int perm_ok = 0, quit, i; 1318 struct stat st; 1319 1320 if (stat(filename, &st) < 0) { 1321 debug3("no such identity: %s", filename); 1322 return NULL; 1323 } 1324 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1325 if (!perm_ok) 1326 return NULL; 1327 if (private == NULL) { 1328 if (options.batch_mode) 1329 return NULL; 1330 snprintf(prompt, sizeof prompt, 1331 "Enter passphrase for key '%.100s': ", filename); 1332 for (i = 0; i < options.number_of_password_prompts; i++) { 1333 passphrase = read_passphrase(prompt, 0); 1334 if (strcmp(passphrase, "") != 0) { 1335 private = key_load_private_type(KEY_UNSPEC, 1336 filename, passphrase, NULL, NULL); 1337 quit = 0; 1338 } else { 1339 debug2("no passphrase given, try next key"); 1340 quit = 1; 1341 } 1342 memset(passphrase, 0, strlen(passphrase)); 1343 xfree(passphrase); 1344 if (private != NULL || quit) 1345 break; 1346 debug2("bad passphrase given, try again..."); 1347 } 1348 } 1349 return private; 1350} 1351 1352/* 1353 * try keys in the following order: 1354 * 1. agent keys that are found in the config file 1355 * 2. other agent keys 1356 * 3. keys that are only listed in the config file 1357 */ 1358static void 1359pubkey_prepare(Authctxt *authctxt) 1360{ 1361 Identity *id; 1362 Idlist agent, files, *preferred; 1363 Key *key; 1364 AuthenticationConnection *ac; 1365 char *comment; 1366 int i, found; 1367 1368 TAILQ_INIT(&agent); /* keys from the agent */ 1369 TAILQ_INIT(&files); /* keys from the config file */ 1370 preferred = &authctxt->keys; 1371 TAILQ_INIT(preferred); /* preferred order of keys */ 1372 1373 /* list of keys stored in the filesystem */ 1374 for (i = 0; i < options.num_identity_files; i++) { 1375 key = options.identity_keys[i]; 1376 if (key && key->type == KEY_RSA1) 1377 continue; 1378 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1379 continue; 1380 options.identity_keys[i] = NULL; 1381 id = xcalloc(1, sizeof(*id)); 1382 id->key = key; 1383 id->filename = xstrdup(options.identity_files[i]); 1384 TAILQ_INSERT_TAIL(&files, id, next); 1385 } 1386 /* list of keys supported by the agent */ 1387 if ((ac = ssh_get_authentication_connection())) { 1388 for (key = ssh_get_first_identity(ac, &comment, 2); 1389 key != NULL; 1390 key = ssh_get_next_identity(ac, &comment, 2)) { 1391 found = 0; 1392 TAILQ_FOREACH(id, &files, next) { 1393 /* agent keys from the config file are preferred */ 1394 if (key_equal(key, id->key)) { 1395 key_free(key); 1396 xfree(comment); 1397 TAILQ_REMOVE(&files, id, next); 1398 TAILQ_INSERT_TAIL(preferred, id, next); 1399 id->ac = ac; 1400 found = 1; 1401 break; 1402 } 1403 } 1404 if (!found && !options.identities_only) { 1405 id = xcalloc(1, sizeof(*id)); 1406 id->key = key; 1407 id->filename = comment; 1408 id->ac = ac; 1409 TAILQ_INSERT_TAIL(&agent, id, next); 1410 } 1411 } 1412 /* append remaining agent keys */ 1413 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1414 TAILQ_REMOVE(&agent, id, next); 1415 TAILQ_INSERT_TAIL(preferred, id, next); 1416 } 1417 authctxt->agent = ac; 1418 } 1419 /* append remaining keys from the config file */ 1420 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1421 TAILQ_REMOVE(&files, id, next); 1422 TAILQ_INSERT_TAIL(preferred, id, next); 1423 } 1424 TAILQ_FOREACH(id, preferred, next) { 1425 debug2("key: %s (%p)", id->filename, id->key); 1426 } 1427} 1428 1429static void 1430pubkey_cleanup(Authctxt *authctxt) 1431{ 1432 Identity *id; 1433 1434 if (authctxt->agent != NULL) 1435 ssh_close_authentication_connection(authctxt->agent); 1436 for (id = TAILQ_FIRST(&authctxt->keys); id; 1437 id = TAILQ_FIRST(&authctxt->keys)) { 1438 TAILQ_REMOVE(&authctxt->keys, id, next); 1439 if (id->key) 1440 key_free(id->key); 1441 if (id->filename) 1442 xfree(id->filename); 1443 xfree(id); 1444 } 1445} 1446 1447int 1448userauth_pubkey(Authctxt *authctxt) 1449{ 1450 Identity *id; 1451 int sent = 0; 1452 1453 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1454 if (id->tried++) 1455 return (0); 1456 /* move key to the end of the queue */ 1457 TAILQ_REMOVE(&authctxt->keys, id, next); 1458 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1459 /* 1460 * send a test message if we have the public key. for 1461 * encrypted keys we cannot do this and have to load the 1462 * private key instead 1463 */ 1464 if (id->key && id->key->type != KEY_RSA1) { 1465 debug("Offering %s public key: %s", key_type(id->key), 1466 id->filename); 1467 sent = send_pubkey_test(authctxt, id); 1468 } else if (id->key == NULL) { 1469 debug("Trying private key: %s", id->filename); 1470 id->key = load_identity_file(id->filename); 1471 if (id->key != NULL) { 1472 id->isprivate = 1; 1473 sent = sign_and_send_pubkey(authctxt, id); 1474 key_free(id->key); 1475 id->key = NULL; 1476 } 1477 } 1478 if (sent) 1479 return (sent); 1480 } 1481 return (0); 1482} 1483 1484/* 1485 * Send userauth request message specifying keyboard-interactive method. 1486 */ 1487int 1488userauth_kbdint(Authctxt *authctxt) 1489{ 1490 static int attempt = 0; 1491 1492 if (attempt++ >= options.number_of_password_prompts) 1493 return 0; 1494 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1495 if (attempt > 1 && !authctxt->info_req_seen) { 1496 debug3("userauth_kbdint: disable: no info_req_seen"); 1497 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1498 return 0; 1499 } 1500 1501 debug2("userauth_kbdint"); 1502 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1503 packet_put_cstring(authctxt->server_user); 1504 packet_put_cstring(authctxt->service); 1505 packet_put_cstring(authctxt->method->name); 1506 packet_put_cstring(""); /* lang */ 1507 packet_put_cstring(options.kbd_interactive_devices ? 1508 options.kbd_interactive_devices : ""); 1509 packet_send(); 1510 1511 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1512 return 1; 1513} 1514 1515/* 1516 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1517 */ 1518void 1519input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1520{ 1521 Authctxt *authctxt = ctxt; 1522 char *name, *inst, *lang, *prompt, *response; 1523 u_int num_prompts, i; 1524 int echo = 0; 1525 1526 debug2("input_userauth_info_req"); 1527 1528 if (authctxt == NULL) 1529 fatal("input_userauth_info_req: no authentication context"); 1530 1531 authctxt->info_req_seen = 1; 1532 1533 name = packet_get_string(NULL); 1534 inst = packet_get_string(NULL); 1535 lang = packet_get_string(NULL); 1536 if (strlen(name) > 0) 1537 logit("%s", name); 1538 if (strlen(inst) > 0) 1539 logit("%s", inst); 1540 xfree(name); 1541 xfree(inst); 1542 xfree(lang); 1543 1544 num_prompts = packet_get_int(); 1545 /* 1546 * Begin to build info response packet based on prompts requested. 1547 * We commit to providing the correct number of responses, so if 1548 * further on we run into a problem that prevents this, we have to 1549 * be sure and clean this up and send a correct error response. 1550 */ 1551 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1552 packet_put_int(num_prompts); 1553 1554 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1555 for (i = 0; i < num_prompts; i++) { 1556 prompt = packet_get_string(NULL); 1557 echo = packet_get_char(); 1558 1559 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1560 1561 packet_put_cstring(response); 1562 memset(response, 0, strlen(response)); 1563 xfree(response); 1564 xfree(prompt); 1565 } 1566 packet_check_eom(); /* done with parsing incoming message. */ 1567 1568 packet_add_padding(64); 1569 packet_send(); 1570} 1571 1572static int 1573ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1574 u_char *data, u_int datalen) 1575{ 1576 Buffer b; 1577 struct stat st; 1578 pid_t pid; 1579 int to[2], from[2], status, version = 2; 1580 1581 debug2("ssh_keysign called"); 1582 1583 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1584 error("ssh_keysign: not installed: %s", strerror(errno)); 1585 return -1; 1586 } 1587 if (fflush(stdout) != 0) 1588 error("ssh_keysign: fflush: %s", strerror(errno)); 1589 if (pipe(to) < 0) { 1590 error("ssh_keysign: pipe: %s", strerror(errno)); 1591 return -1; 1592 } 1593 if (pipe(from) < 0) { 1594 error("ssh_keysign: pipe: %s", strerror(errno)); 1595 return -1; 1596 } 1597 if ((pid = fork()) < 0) { 1598 error("ssh_keysign: fork: %s", strerror(errno)); 1599 return -1; 1600 } 1601 if (pid == 0) { 1602 /* keep the socket on exec */ 1603 fcntl(packet_get_connection_in(), F_SETFD, 0); 1604 permanently_drop_suid(getuid()); 1605 close(from[0]); 1606 if (dup2(from[1], STDOUT_FILENO) < 0) 1607 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1608 close(to[1]); 1609 if (dup2(to[0], STDIN_FILENO) < 0) 1610 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1611 close(from[1]); 1612 close(to[0]); 1613 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1614 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1615 strerror(errno)); 1616 } 1617 close(from[1]); 1618 close(to[0]); 1619 1620 buffer_init(&b); 1621 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1622 buffer_put_string(&b, data, datalen); 1623 if (ssh_msg_send(to[1], version, &b) == -1) 1624 fatal("ssh_keysign: couldn't send request"); 1625 1626 if (ssh_msg_recv(from[0], &b) < 0) { 1627 error("ssh_keysign: no reply"); 1628 buffer_free(&b); 1629 return -1; 1630 } 1631 close(from[0]); 1632 close(to[1]); 1633 1634 while (waitpid(pid, &status, 0) < 0) 1635 if (errno != EINTR) 1636 break; 1637 1638 if (buffer_get_char(&b) != version) { 1639 error("ssh_keysign: bad version"); 1640 buffer_free(&b); 1641 return -1; 1642 } 1643 *sigp = buffer_get_string(&b, lenp); 1644 buffer_free(&b); 1645 1646 return 0; 1647} 1648 1649int 1650userauth_hostbased(Authctxt *authctxt) 1651{ 1652 Key *private = NULL; 1653 Sensitive *sensitive = authctxt->sensitive; 1654 Buffer b; 1655 u_char *signature, *blob; 1656 char *chost, *pkalg, *p; 1657 const char *service; 1658 u_int blen, slen; 1659 int ok, i, found = 0; 1660 1661 /* check for a useful key */ 1662 for (i = 0; i < sensitive->nkeys; i++) { 1663 private = sensitive->keys[i]; 1664 if (private && private->type != KEY_RSA1) { 1665 found = 1; 1666 /* we take and free the key */ 1667 sensitive->keys[i] = NULL; 1668 break; 1669 } 1670 } 1671 if (!found) { 1672 debug("No more client hostkeys for hostbased authentication."); 1673 return 0; 1674 } 1675 if (key_to_blob(private, &blob, &blen) == 0) { 1676 key_free(private); 1677 return 0; 1678 } 1679 /* figure out a name for the client host */ 1680 p = get_local_name(packet_get_connection_in()); 1681 if (p == NULL) { 1682 error("userauth_hostbased: cannot get local ipaddr/name"); 1683 key_free(private); 1684 xfree(blob); 1685 return 0; 1686 } 1687 xasprintf(&chost, "%s.", p); 1688 debug2("userauth_hostbased: chost %s", chost); 1689 xfree(p); 1690 1691 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1692 authctxt->service; 1693 pkalg = xstrdup(key_ssh_name(private)); 1694 buffer_init(&b); 1695 /* construct data */ 1696 buffer_put_string(&b, session_id2, session_id2_len); 1697 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1698 buffer_put_cstring(&b, authctxt->server_user); 1699 buffer_put_cstring(&b, service); 1700 buffer_put_cstring(&b, authctxt->method->name); 1701 buffer_put_cstring(&b, pkalg); 1702 buffer_put_string(&b, blob, blen); 1703 buffer_put_cstring(&b, chost); 1704 buffer_put_cstring(&b, authctxt->local_user); 1705#ifdef DEBUG_PK 1706 buffer_dump(&b); 1707#endif 1708 if (sensitive->external_keysign) 1709 ok = ssh_keysign(private, &signature, &slen, 1710 buffer_ptr(&b), buffer_len(&b)); 1711 else 1712 ok = key_sign(private, &signature, &slen, 1713 buffer_ptr(&b), buffer_len(&b)); 1714 key_free(private); 1715 buffer_free(&b); 1716 if (ok != 0) { 1717 error("key_sign failed"); 1718 xfree(chost); 1719 xfree(pkalg); 1720 xfree(blob); 1721 return 0; 1722 } 1723 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1724 packet_put_cstring(authctxt->server_user); 1725 packet_put_cstring(authctxt->service); 1726 packet_put_cstring(authctxt->method->name); 1727 packet_put_cstring(pkalg); 1728 packet_put_string(blob, blen); 1729 packet_put_cstring(chost); 1730 packet_put_cstring(authctxt->local_user); 1731 packet_put_string(signature, slen); 1732 memset(signature, 's', slen); 1733 xfree(signature); 1734 xfree(chost); 1735 xfree(pkalg); 1736 xfree(blob); 1737 1738 packet_send(); 1739 return 1; 1740} 1741 1742#ifdef JPAKE 1743int 1744userauth_jpake(Authctxt *authctxt) 1745{ 1746 struct jpake_ctx *pctx; 1747 u_char *x1_proof, *x2_proof; 1748 u_int x1_proof_len, x2_proof_len; 1749 static int attempt = 0; /* XXX share with userauth_password's? */ 1750 1751 if (attempt++ >= options.number_of_password_prompts) 1752 return 0; 1753 if (attempt != 1) 1754 error("Permission denied, please try again."); 1755 1756 if (authctxt->methoddata != NULL) 1757 fatal("%s: authctxt->methoddata already set (%p)", 1758 __func__, authctxt->methoddata); 1759 1760 authctxt->methoddata = pctx = jpake_new(); 1761 1762 /* 1763 * Send request immediately, to get the protocol going while 1764 * we do the initial computations. 1765 */ 1766 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1767 packet_put_cstring(authctxt->server_user); 1768 packet_put_cstring(authctxt->service); 1769 packet_put_cstring(authctxt->method->name); 1770 packet_send(); 1771 packet_write_wait(); 1772 1773 jpake_step1(pctx->grp, 1774 &pctx->client_id, &pctx->client_id_len, 1775 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1776 &x1_proof, &x1_proof_len, 1777 &x2_proof, &x2_proof_len); 1778 1779 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1780 1781 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1782 packet_put_string(pctx->client_id, pctx->client_id_len); 1783 packet_put_bignum2(pctx->g_x1); 1784 packet_put_bignum2(pctx->g_x2); 1785 packet_put_string(x1_proof, x1_proof_len); 1786 packet_put_string(x2_proof, x2_proof_len); 1787 packet_send(); 1788 1789 bzero(x1_proof, x1_proof_len); 1790 bzero(x2_proof, x2_proof_len); 1791 xfree(x1_proof); 1792 xfree(x2_proof); 1793 1794 /* Expect step 1 packet from peer */ 1795 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1796 input_userauth_jpake_server_step1); 1797 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1798 &input_userauth_success_unexpected); 1799 1800 return 1; 1801} 1802 1803void 1804userauth_jpake_cleanup(Authctxt *authctxt) 1805{ 1806 debug3("%s: clean up", __func__); 1807 if (authctxt->methoddata != NULL) { 1808 jpake_free(authctxt->methoddata); 1809 authctxt->methoddata = NULL; 1810 } 1811 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1812} 1813#endif /* JPAKE */ 1814 1815/* find auth method */ 1816 1817/* 1818 * given auth method name, if configurable options permit this method fill 1819 * in auth_ident field and return true, otherwise return false. 1820 */ 1821static int 1822authmethod_is_enabled(Authmethod *method) 1823{ 1824 if (method == NULL) 1825 return 0; 1826 /* return false if options indicate this method is disabled */ 1827 if (method->enabled == NULL || *method->enabled == 0) 1828 return 0; 1829 /* return false if batch mode is enabled but method needs interactive mode */ 1830 if (method->batch_flag != NULL && *method->batch_flag != 0) 1831 return 0; 1832 return 1; 1833} 1834 1835static Authmethod * 1836authmethod_lookup(const char *name) 1837{ 1838 Authmethod *method = NULL; 1839 if (name != NULL) 1840 for (method = authmethods; method->name != NULL; method++) 1841 if (strcmp(name, method->name) == 0) 1842 return method; 1843 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1844 return NULL; 1845} 1846 1847/* XXX internal state */ 1848static Authmethod *current = NULL; 1849static char *supported = NULL; 1850static char *preferred = NULL; 1851 1852/* 1853 * Given the authentication method list sent by the server, return the 1854 * next method we should try. If the server initially sends a nil list, 1855 * use a built-in default list. 1856 */ 1857static Authmethod * 1858authmethod_get(char *authlist) 1859{ 1860 char *name = NULL; 1861 u_int next; 1862 1863 /* Use a suitable default if we're passed a nil list. */ 1864 if (authlist == NULL || strlen(authlist) == 0) 1865 authlist = options.preferred_authentications; 1866 1867 if (supported == NULL || strcmp(authlist, supported) != 0) { 1868 debug3("start over, passed a different list %s", authlist); 1869 if (supported != NULL) 1870 xfree(supported); 1871 supported = xstrdup(authlist); 1872 preferred = options.preferred_authentications; 1873 debug3("preferred %s", preferred); 1874 current = NULL; 1875 } else if (current != NULL && authmethod_is_enabled(current)) 1876 return current; 1877 1878 for (;;) { 1879 if ((name = match_list(preferred, supported, &next)) == NULL) { 1880 debug("No more authentication methods to try."); 1881 current = NULL; 1882 return NULL; 1883 } 1884 preferred += next; 1885 debug3("authmethod_lookup %s", name); 1886 debug3("remaining preferred: %s", preferred); 1887 if ((current = authmethod_lookup(name)) != NULL && 1888 authmethod_is_enabled(current)) { 1889 debug3("authmethod_is_enabled %s", name); 1890 debug("Next authentication method: %s", name); 1891 return current; 1892 } 1893 } 1894} 1895 1896static char * 1897authmethods_get(void) 1898{ 1899 Authmethod *method = NULL; 1900 Buffer b; 1901 char *list; 1902 1903 buffer_init(&b); 1904 for (method = authmethods; method->name != NULL; method++) { 1905 if (authmethod_is_enabled(method)) { 1906 if (buffer_len(&b) > 0) 1907 buffer_append(&b, ",", 1); 1908 buffer_append(&b, method->name, strlen(method->name)); 1909 } 1910 } 1911 buffer_append(&b, "\0", 1); 1912 list = xstrdup(buffer_ptr(&b)); 1913 buffer_free(&b); 1914 return list; 1915} 1916 1917