sshconnect2.c revision 224640
1/* $OpenBSD: sshconnect2.c,v 1.186 2010/11/29 23:45:51 djm Exp $ */ 2/* $FreeBSD: head/crypto/openssh/sshconnect2.c 224640 2011-08-03 20:00:36Z brooks $ */ 3/* 4 * Copyright (c) 2000 Markus Friedl. All rights reserved. 5 * Copyright (c) 2008 Damien Miller. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28#include "includes.h" 29 30#include <sys/types.h> 31#include <sys/socket.h> 32#include <sys/wait.h> 33#include <sys/stat.h> 34 35#include <errno.h> 36#include <fcntl.h> 37#include <netdb.h> 38#include <pwd.h> 39#include <signal.h> 40#include <stdarg.h> 41#include <stdio.h> 42#include <string.h> 43#include <unistd.h> 44#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) 45#include <vis.h> 46#endif 47 48#include "openbsd-compat/sys-queue.h" 49 50#include "xmalloc.h" 51#include "ssh.h" 52#include "ssh2.h" 53#include "buffer.h" 54#include "packet.h" 55#include "compat.h" 56#include "cipher.h" 57#include "key.h" 58#include "kex.h" 59#include "myproposal.h" 60#include "sshconnect.h" 61#include "authfile.h" 62#include "dh.h" 63#include "authfd.h" 64#include "log.h" 65#include "readconf.h" 66#include "misc.h" 67#include "match.h" 68#include "dispatch.h" 69#include "canohost.h" 70#include "msg.h" 71#include "pathnames.h" 72#include "uidswap.h" 73#include "hostfile.h" 74#include "schnorr.h" 75#include "jpake.h" 76 77#ifdef GSSAPI 78#include "ssh-gss.h" 79#endif 80 81/* import */ 82extern char *client_version_string; 83extern char *server_version_string; 84extern Options options; 85#ifdef NONE_CIPHER_ENABLED 86extern Kex *xxx_kex; 87 88/* 89 * tty_flag is set in ssh.c so we can use it here. If set then prevent 90 * the switch to the null cipher. 91 */ 92 93extern int tty_flag; 94#endif 95 96/* 97 * SSH2 key exchange 98 */ 99 100u_char *session_id2 = NULL; 101u_int session_id2_len = 0; 102 103char *xxx_host; 104struct sockaddr *xxx_hostaddr; 105 106Kex *xxx_kex = NULL; 107 108static int 109verify_host_key_callback(Key *hostkey) 110{ 111 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 112 fatal("Host key verification failed."); 113 return 0; 114} 115 116static char * 117order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 118{ 119 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 120 size_t maxlen; 121 struct hostkeys *hostkeys; 122 int ktype; 123 124 /* Find all hostkeys for this hostname */ 125 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 126 hostkeys = init_hostkeys(); 127 load_hostkeys(hostkeys, hostname, options.user_hostfile2); 128 load_hostkeys(hostkeys, hostname, options.system_hostfile2); 129 load_hostkeys(hostkeys, hostname, options.user_hostfile); 130 load_hostkeys(hostkeys, hostname, options.system_hostfile); 131 132 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 133 maxlen = strlen(avail) + 1; 134 first = xmalloc(maxlen); 135 last = xmalloc(maxlen); 136 *first = *last = '\0'; 137 138#define ALG_APPEND(to, from) \ 139 do { \ 140 if (*to != '\0') \ 141 strlcat(to, ",", maxlen); \ 142 strlcat(to, from, maxlen); \ 143 } while (0) 144 145 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 146 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) 147 fatal("%s: unknown alg %s", __func__, alg); 148 if (lookup_key_in_hostkeys_by_type(hostkeys, 149 key_type_plain(ktype), NULL)) 150 ALG_APPEND(first, alg); 151 else 152 ALG_APPEND(last, alg); 153 } 154#undef ALG_APPEND 155 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); 156 if (*first != '\0') 157 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 158 159 xfree(first); 160 xfree(last); 161 xfree(hostname); 162 xfree(oavail); 163 free_hostkeys(hostkeys); 164 165 return ret; 166} 167 168void 169ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 170{ 171 Kex *kex; 172 173 xxx_host = host; 174 xxx_hostaddr = hostaddr; 175 176 if (options.ciphers == (char *)-1) { 177 logit("No valid ciphers for protocol version 2 given, using defaults."); 178 options.ciphers = NULL; 179 } 180 if (options.ciphers != NULL) { 181 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 182 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 183 } 184 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 185 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 186 myproposal[PROPOSAL_ENC_ALGS_STOC] = 187 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 188 if (options.compression) { 189 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 190 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 191 } else { 192 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 193 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 194 } 195 if (options.macs != NULL) { 196 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 197 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 198 } 199 if (options.hostkeyalgorithms != NULL) 200 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 201 options.hostkeyalgorithms; 202 else { 203 /* Prefer algorithms that we already have keys for */ 204 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 205 order_hostkeyalgs(host, hostaddr, port); 206 } 207 if (options.kex_algorithms != NULL) 208 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 209 210 if (options.rekey_limit) 211 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 212 213 /* start key exchange */ 214 kex = kex_setup(myproposal); 215 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 216 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 217 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 218 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 219 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 220 kex->client_version_string=client_version_string; 221 kex->server_version_string=server_version_string; 222 kex->verify_host_key=&verify_host_key_callback; 223 224 xxx_kex = kex; 225 226 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 227 228 if (options.use_roaming && !kex->roaming) { 229 debug("Roaming not allowed by server"); 230 options.use_roaming = 0; 231 } 232 233 session_id2 = kex->session_id; 234 session_id2_len = kex->session_id_len; 235 236#ifdef DEBUG_KEXDH 237 /* send 1st encrypted/maced/compressed message */ 238 packet_start(SSH2_MSG_IGNORE); 239 packet_put_cstring("markus"); 240 packet_send(); 241 packet_write_wait(); 242#endif 243} 244 245/* 246 * Authenticate user 247 */ 248 249typedef struct Authctxt Authctxt; 250typedef struct Authmethod Authmethod; 251typedef struct identity Identity; 252typedef struct idlist Idlist; 253 254struct identity { 255 TAILQ_ENTRY(identity) next; 256 AuthenticationConnection *ac; /* set if agent supports key */ 257 Key *key; /* public/private key */ 258 char *filename; /* comment for agent-only keys */ 259 int tried; 260 int isprivate; /* key points to the private key */ 261}; 262TAILQ_HEAD(idlist, identity); 263 264struct Authctxt { 265 const char *server_user; 266 const char *local_user; 267 const char *host; 268 const char *service; 269 Authmethod *method; 270 sig_atomic_t success; 271 char *authlist; 272 /* pubkey */ 273 Idlist keys; 274 AuthenticationConnection *agent; 275 /* hostbased */ 276 Sensitive *sensitive; 277 /* kbd-interactive */ 278 int info_req_seen; 279 /* generic */ 280 void *methoddata; 281}; 282struct Authmethod { 283 char *name; /* string to compare against server's list */ 284 int (*userauth)(Authctxt *authctxt); 285 void (*cleanup)(Authctxt *authctxt); 286 int *enabled; /* flag in option struct that enables method */ 287 int *batch_flag; /* flag in option struct that disables method */ 288}; 289 290void input_userauth_success(int, u_int32_t, void *); 291void input_userauth_success_unexpected(int, u_int32_t, void *); 292void input_userauth_failure(int, u_int32_t, void *); 293void input_userauth_banner(int, u_int32_t, void *); 294void input_userauth_error(int, u_int32_t, void *); 295void input_userauth_info_req(int, u_int32_t, void *); 296void input_userauth_pk_ok(int, u_int32_t, void *); 297void input_userauth_passwd_changereq(int, u_int32_t, void *); 298void input_userauth_jpake_server_step1(int, u_int32_t, void *); 299void input_userauth_jpake_server_step2(int, u_int32_t, void *); 300void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 301 302int userauth_none(Authctxt *); 303int userauth_pubkey(Authctxt *); 304int userauth_passwd(Authctxt *); 305int userauth_kbdint(Authctxt *); 306int userauth_hostbased(Authctxt *); 307int userauth_jpake(Authctxt *); 308 309void userauth_jpake_cleanup(Authctxt *); 310 311#ifdef GSSAPI 312int userauth_gssapi(Authctxt *authctxt); 313void input_gssapi_response(int type, u_int32_t, void *); 314void input_gssapi_token(int type, u_int32_t, void *); 315void input_gssapi_hash(int type, u_int32_t, void *); 316void input_gssapi_error(int, u_int32_t, void *); 317void input_gssapi_errtok(int, u_int32_t, void *); 318#endif 319 320void userauth(Authctxt *, char *); 321 322static int sign_and_send_pubkey(Authctxt *, Identity *); 323static void pubkey_prepare(Authctxt *); 324static void pubkey_cleanup(Authctxt *); 325static Key *load_identity_file(char *); 326 327static Authmethod *authmethod_get(char *authlist); 328static Authmethod *authmethod_lookup(const char *name); 329static char *authmethods_get(void); 330 331Authmethod authmethods[] = { 332#ifdef GSSAPI 333 {"gssapi-with-mic", 334 userauth_gssapi, 335 NULL, 336 &options.gss_authentication, 337 NULL}, 338#endif 339 {"hostbased", 340 userauth_hostbased, 341 NULL, 342 &options.hostbased_authentication, 343 NULL}, 344 {"publickey", 345 userauth_pubkey, 346 NULL, 347 &options.pubkey_authentication, 348 NULL}, 349#ifdef JPAKE 350 {"jpake-01@openssh.com", 351 userauth_jpake, 352 userauth_jpake_cleanup, 353 &options.zero_knowledge_password_authentication, 354 &options.batch_mode}, 355#endif 356 {"keyboard-interactive", 357 userauth_kbdint, 358 NULL, 359 &options.kbd_interactive_authentication, 360 &options.batch_mode}, 361 {"password", 362 userauth_passwd, 363 NULL, 364 &options.password_authentication, 365 &options.batch_mode}, 366 {"none", 367 userauth_none, 368 NULL, 369 NULL, 370 NULL}, 371 {NULL, NULL, NULL, NULL, NULL} 372}; 373 374void 375ssh_userauth2(const char *local_user, const char *server_user, char *host, 376 Sensitive *sensitive) 377{ 378 Authctxt authctxt; 379 int type; 380 381 if (options.challenge_response_authentication) 382 options.kbd_interactive_authentication = 1; 383 384 packet_start(SSH2_MSG_SERVICE_REQUEST); 385 packet_put_cstring("ssh-userauth"); 386 packet_send(); 387 debug("SSH2_MSG_SERVICE_REQUEST sent"); 388 packet_write_wait(); 389 type = packet_read(); 390 if (type != SSH2_MSG_SERVICE_ACCEPT) 391 fatal("Server denied authentication request: %d", type); 392 if (packet_remaining() > 0) { 393 char *reply = packet_get_string(NULL); 394 debug2("service_accept: %s", reply); 395 xfree(reply); 396 } else { 397 debug2("buggy server: service_accept w/o service"); 398 } 399 packet_check_eom(); 400 debug("SSH2_MSG_SERVICE_ACCEPT received"); 401 402 if (options.preferred_authentications == NULL) 403 options.preferred_authentications = authmethods_get(); 404 405 /* setup authentication context */ 406 memset(&authctxt, 0, sizeof(authctxt)); 407 pubkey_prepare(&authctxt); 408 authctxt.server_user = server_user; 409 authctxt.local_user = local_user; 410 authctxt.host = host; 411 authctxt.service = "ssh-connection"; /* service name */ 412 authctxt.success = 0; 413 authctxt.method = authmethod_lookup("none"); 414 authctxt.authlist = NULL; 415 authctxt.methoddata = NULL; 416 authctxt.sensitive = sensitive; 417 authctxt.info_req_seen = 0; 418 if (authctxt.method == NULL) 419 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 420 421 /* initial userauth request */ 422 userauth_none(&authctxt); 423 424 dispatch_init(&input_userauth_error); 425 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 426 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 427 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 428 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 429 430 pubkey_cleanup(&authctxt); 431 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 432 433#ifdef NONE_CIPHER_ENABLED 434 /* 435 * If the user explicitly requests to use the none cipher enable it 436 * post authentication and only if the right conditions are met: both 437 * of the NONE switches must be true and there must be no tty allocated. 438 */ 439 if (options.none_switch == 1 && options.none_enabled == 1) { 440 if (!tty_flag) { 441 debug("Requesting none cipher re-keying..."); 442 myproposal[PROPOSAL_ENC_ALGS_STOC] = "none"; 443 myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none"; 444 kex_prop2buf(&xxx_kex->my, myproposal); 445 packet_request_rekeying(); 446 fprintf(stderr, "WARNING: enabled NONE cipher\n"); 447 } else { 448 /* Requested NONE cipher on an interactive session. */ 449 debug("Cannot switch to NONE cipher with tty " 450 "allocated"); 451 fprintf(stderr, "NONE cipher switch disabled given " 452 "a TTY is allocated\n"); 453 } 454 } 455#endif 456 debug("Authentication succeeded (%s).", authctxt.method->name); 457} 458 459void 460userauth(Authctxt *authctxt, char *authlist) 461{ 462 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 463 authctxt->method->cleanup(authctxt); 464 465 if (authctxt->methoddata) { 466 xfree(authctxt->methoddata); 467 authctxt->methoddata = NULL; 468 } 469 if (authlist == NULL) { 470 authlist = authctxt->authlist; 471 } else { 472 if (authctxt->authlist) 473 xfree(authctxt->authlist); 474 authctxt->authlist = authlist; 475 } 476 for (;;) { 477 Authmethod *method = authmethod_get(authlist); 478 if (method == NULL) 479 fatal("Permission denied (%s).", authlist); 480 authctxt->method = method; 481 482 /* reset the per method handler */ 483 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 484 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 485 486 /* and try new method */ 487 if (method->userauth(authctxt) != 0) { 488 debug2("we sent a %s packet, wait for reply", method->name); 489 break; 490 } else { 491 debug2("we did not send a packet, disable method"); 492 method->enabled = NULL; 493 } 494 } 495} 496 497/* ARGSUSED */ 498void 499input_userauth_error(int type, u_int32_t seq, void *ctxt) 500{ 501 fatal("input_userauth_error: bad message during authentication: " 502 "type %d", type); 503} 504 505/* ARGSUSED */ 506void 507input_userauth_banner(int type, u_int32_t seq, void *ctxt) 508{ 509 char *msg, *raw, *lang; 510 u_int len; 511 512 debug3("input_userauth_banner"); 513 raw = packet_get_string(&len); 514 lang = packet_get_string(NULL); 515 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 516 if (len > 65536) 517 len = 65536; 518 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 519 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 520 fprintf(stderr, "%s", msg); 521 xfree(msg); 522 } 523 xfree(raw); 524 xfree(lang); 525} 526 527/* ARGSUSED */ 528void 529input_userauth_success(int type, u_int32_t seq, void *ctxt) 530{ 531 Authctxt *authctxt = ctxt; 532 533 if (authctxt == NULL) 534 fatal("input_userauth_success: no authentication context"); 535 if (authctxt->authlist) { 536 xfree(authctxt->authlist); 537 authctxt->authlist = NULL; 538 } 539 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 540 authctxt->method->cleanup(authctxt); 541 if (authctxt->methoddata) { 542 xfree(authctxt->methoddata); 543 authctxt->methoddata = NULL; 544 } 545 authctxt->success = 1; /* break out */ 546} 547 548void 549input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 550{ 551 Authctxt *authctxt = ctxt; 552 553 if (authctxt == NULL) 554 fatal("%s: no authentication context", __func__); 555 556 fatal("Unexpected authentication success during %s.", 557 authctxt->method->name); 558} 559 560/* ARGSUSED */ 561void 562input_userauth_failure(int type, u_int32_t seq, void *ctxt) 563{ 564 Authctxt *authctxt = ctxt; 565 char *authlist = NULL; 566 int partial; 567 568 if (authctxt == NULL) 569 fatal("input_userauth_failure: no authentication context"); 570 571 authlist = packet_get_string(NULL); 572 partial = packet_get_char(); 573 packet_check_eom(); 574 575 if (partial != 0) 576 logit("Authenticated with partial success."); 577 debug("Authentications that can continue: %s", authlist); 578 579 userauth(authctxt, authlist); 580} 581 582/* ARGSUSED */ 583void 584input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 585{ 586 Authctxt *authctxt = ctxt; 587 Key *key = NULL; 588 Identity *id = NULL; 589 Buffer b; 590 int pktype, sent = 0; 591 u_int alen, blen; 592 char *pkalg, *fp; 593 u_char *pkblob; 594 595 if (authctxt == NULL) 596 fatal("input_userauth_pk_ok: no authentication context"); 597 if (datafellows & SSH_BUG_PKOK) { 598 /* this is similar to SSH_BUG_PKAUTH */ 599 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 600 pkblob = packet_get_string(&blen); 601 buffer_init(&b); 602 buffer_append(&b, pkblob, blen); 603 pkalg = buffer_get_string(&b, &alen); 604 buffer_free(&b); 605 } else { 606 pkalg = packet_get_string(&alen); 607 pkblob = packet_get_string(&blen); 608 } 609 packet_check_eom(); 610 611 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 612 613 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 614 debug("unknown pkalg %s", pkalg); 615 goto done; 616 } 617 if ((key = key_from_blob(pkblob, blen)) == NULL) { 618 debug("no key from blob. pkalg %s", pkalg); 619 goto done; 620 } 621 if (key->type != pktype) { 622 error("input_userauth_pk_ok: type mismatch " 623 "for decoded key (received %d, expected %d)", 624 key->type, pktype); 625 goto done; 626 } 627 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 628 debug2("input_userauth_pk_ok: fp %s", fp); 629 xfree(fp); 630 631 /* 632 * search keys in the reverse order, because last candidate has been 633 * moved to the end of the queue. this also avoids confusion by 634 * duplicate keys 635 */ 636 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 637 if (key_equal(key, id->key)) { 638 sent = sign_and_send_pubkey(authctxt, id); 639 break; 640 } 641 } 642done: 643 if (key != NULL) 644 key_free(key); 645 xfree(pkalg); 646 xfree(pkblob); 647 648 /* try another method if we did not send a packet */ 649 if (sent == 0) 650 userauth(authctxt, NULL); 651} 652 653#ifdef GSSAPI 654int 655userauth_gssapi(Authctxt *authctxt) 656{ 657 Gssctxt *gssctxt = NULL; 658 static gss_OID_set gss_supported = NULL; 659 static u_int mech = 0; 660 OM_uint32 min; 661 int ok = 0; 662 663 /* Try one GSSAPI method at a time, rather than sending them all at 664 * once. */ 665 666 if (gss_supported == NULL) 667 gss_indicate_mechs(&min, &gss_supported); 668 669 /* Check to see if the mechanism is usable before we offer it */ 670 while (mech < gss_supported->count && !ok) { 671 /* My DER encoding requires length<128 */ 672 if (gss_supported->elements[mech].length < 128 && 673 ssh_gssapi_check_mechanism(&gssctxt, 674 &gss_supported->elements[mech], authctxt->host)) { 675 ok = 1; /* Mechanism works */ 676 } else { 677 mech++; 678 } 679 } 680 681 if (!ok) 682 return 0; 683 684 authctxt->methoddata=(void *)gssctxt; 685 686 packet_start(SSH2_MSG_USERAUTH_REQUEST); 687 packet_put_cstring(authctxt->server_user); 688 packet_put_cstring(authctxt->service); 689 packet_put_cstring(authctxt->method->name); 690 691 packet_put_int(1); 692 693 packet_put_int((gss_supported->elements[mech].length) + 2); 694 packet_put_char(SSH_GSS_OIDTYPE); 695 packet_put_char(gss_supported->elements[mech].length); 696 packet_put_raw(gss_supported->elements[mech].elements, 697 gss_supported->elements[mech].length); 698 699 packet_send(); 700 701 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 702 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 703 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 704 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 705 706 mech++; /* Move along to next candidate */ 707 708 return 1; 709} 710 711static OM_uint32 712process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 713{ 714 Authctxt *authctxt = ctxt; 715 Gssctxt *gssctxt = authctxt->methoddata; 716 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 717 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 718 gss_buffer_desc gssbuf; 719 OM_uint32 status, ms, flags; 720 Buffer b; 721 722 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 723 recv_tok, &send_tok, &flags); 724 725 if (send_tok.length > 0) { 726 if (GSS_ERROR(status)) 727 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 728 else 729 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 730 731 packet_put_string(send_tok.value, send_tok.length); 732 packet_send(); 733 gss_release_buffer(&ms, &send_tok); 734 } 735 736 if (status == GSS_S_COMPLETE) { 737 /* send either complete or MIC, depending on mechanism */ 738 if (!(flags & GSS_C_INTEG_FLAG)) { 739 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 740 packet_send(); 741 } else { 742 ssh_gssapi_buildmic(&b, authctxt->server_user, 743 authctxt->service, "gssapi-with-mic"); 744 745 gssbuf.value = buffer_ptr(&b); 746 gssbuf.length = buffer_len(&b); 747 748 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 749 750 if (!GSS_ERROR(status)) { 751 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 752 packet_put_string(mic.value, mic.length); 753 754 packet_send(); 755 } 756 757 buffer_free(&b); 758 gss_release_buffer(&ms, &mic); 759 } 760 } 761 762 return status; 763} 764 765/* ARGSUSED */ 766void 767input_gssapi_response(int type, u_int32_t plen, void *ctxt) 768{ 769 Authctxt *authctxt = ctxt; 770 Gssctxt *gssctxt; 771 int oidlen; 772 char *oidv; 773 774 if (authctxt == NULL) 775 fatal("input_gssapi_response: no authentication context"); 776 gssctxt = authctxt->methoddata; 777 778 /* Setup our OID */ 779 oidv = packet_get_string(&oidlen); 780 781 if (oidlen <= 2 || 782 oidv[0] != SSH_GSS_OIDTYPE || 783 oidv[1] != oidlen - 2) { 784 xfree(oidv); 785 debug("Badly encoded mechanism OID received"); 786 userauth(authctxt, NULL); 787 return; 788 } 789 790 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 791 fatal("Server returned different OID than expected"); 792 793 packet_check_eom(); 794 795 xfree(oidv); 796 797 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 798 /* Start again with next method on list */ 799 debug("Trying to start again"); 800 userauth(authctxt, NULL); 801 return; 802 } 803} 804 805/* ARGSUSED */ 806void 807input_gssapi_token(int type, u_int32_t plen, void *ctxt) 808{ 809 Authctxt *authctxt = ctxt; 810 gss_buffer_desc recv_tok; 811 OM_uint32 status; 812 u_int slen; 813 814 if (authctxt == NULL) 815 fatal("input_gssapi_response: no authentication context"); 816 817 recv_tok.value = packet_get_string(&slen); 818 recv_tok.length = slen; /* safe typecast */ 819 820 packet_check_eom(); 821 822 status = process_gssapi_token(ctxt, &recv_tok); 823 824 xfree(recv_tok.value); 825 826 if (GSS_ERROR(status)) { 827 /* Start again with the next method in the list */ 828 userauth(authctxt, NULL); 829 return; 830 } 831} 832 833/* ARGSUSED */ 834void 835input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 836{ 837 Authctxt *authctxt = ctxt; 838 Gssctxt *gssctxt; 839 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 840 gss_buffer_desc recv_tok; 841 OM_uint32 status, ms; 842 u_int len; 843 844 if (authctxt == NULL) 845 fatal("input_gssapi_response: no authentication context"); 846 gssctxt = authctxt->methoddata; 847 848 recv_tok.value = packet_get_string(&len); 849 recv_tok.length = len; 850 851 packet_check_eom(); 852 853 /* Stick it into GSSAPI and see what it says */ 854 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 855 &recv_tok, &send_tok, NULL); 856 857 xfree(recv_tok.value); 858 gss_release_buffer(&ms, &send_tok); 859 860 /* Server will be returning a failed packet after this one */ 861} 862 863/* ARGSUSED */ 864void 865input_gssapi_error(int type, u_int32_t plen, void *ctxt) 866{ 867 OM_uint32 maj, min; 868 char *msg; 869 char *lang; 870 871 maj=packet_get_int(); 872 min=packet_get_int(); 873 msg=packet_get_string(NULL); 874 lang=packet_get_string(NULL); 875 876 packet_check_eom(); 877 878 debug("Server GSSAPI Error:\n%s", msg); 879 xfree(msg); 880 xfree(lang); 881} 882#endif /* GSSAPI */ 883 884int 885userauth_none(Authctxt *authctxt) 886{ 887 /* initial userauth request */ 888 packet_start(SSH2_MSG_USERAUTH_REQUEST); 889 packet_put_cstring(authctxt->server_user); 890 packet_put_cstring(authctxt->service); 891 packet_put_cstring(authctxt->method->name); 892 packet_send(); 893 return 1; 894} 895 896int 897userauth_passwd(Authctxt *authctxt) 898{ 899 static int attempt = 0; 900 char prompt[150]; 901 char *password; 902 const char *host = options.host_key_alias ? options.host_key_alias : 903 authctxt->host; 904 905 if (attempt++ >= options.number_of_password_prompts) 906 return 0; 907 908 if (attempt != 1) 909 error("Permission denied, please try again."); 910 911 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 912 authctxt->server_user, host); 913 password = read_passphrase(prompt, 0); 914 packet_start(SSH2_MSG_USERAUTH_REQUEST); 915 packet_put_cstring(authctxt->server_user); 916 packet_put_cstring(authctxt->service); 917 packet_put_cstring(authctxt->method->name); 918 packet_put_char(0); 919 packet_put_cstring(password); 920 memset(password, 0, strlen(password)); 921 xfree(password); 922 packet_add_padding(64); 923 packet_send(); 924 925 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 926 &input_userauth_passwd_changereq); 927 928 return 1; 929} 930 931/* 932 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 933 */ 934/* ARGSUSED */ 935void 936input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 937{ 938 Authctxt *authctxt = ctxt; 939 char *info, *lang, *password = NULL, *retype = NULL; 940 char prompt[150]; 941 const char *host = options.host_key_alias ? options.host_key_alias : 942 authctxt->host; 943 944 debug2("input_userauth_passwd_changereq"); 945 946 if (authctxt == NULL) 947 fatal("input_userauth_passwd_changereq: " 948 "no authentication context"); 949 950 info = packet_get_string(NULL); 951 lang = packet_get_string(NULL); 952 if (strlen(info) > 0) 953 logit("%s", info); 954 xfree(info); 955 xfree(lang); 956 packet_start(SSH2_MSG_USERAUTH_REQUEST); 957 packet_put_cstring(authctxt->server_user); 958 packet_put_cstring(authctxt->service); 959 packet_put_cstring(authctxt->method->name); 960 packet_put_char(1); /* additional info */ 961 snprintf(prompt, sizeof(prompt), 962 "Enter %.30s@%.128s's old password: ", 963 authctxt->server_user, host); 964 password = read_passphrase(prompt, 0); 965 packet_put_cstring(password); 966 memset(password, 0, strlen(password)); 967 xfree(password); 968 password = NULL; 969 while (password == NULL) { 970 snprintf(prompt, sizeof(prompt), 971 "Enter %.30s@%.128s's new password: ", 972 authctxt->server_user, host); 973 password = read_passphrase(prompt, RP_ALLOW_EOF); 974 if (password == NULL) { 975 /* bail out */ 976 return; 977 } 978 snprintf(prompt, sizeof(prompt), 979 "Retype %.30s@%.128s's new password: ", 980 authctxt->server_user, host); 981 retype = read_passphrase(prompt, 0); 982 if (strcmp(password, retype) != 0) { 983 memset(password, 0, strlen(password)); 984 xfree(password); 985 logit("Mismatch; try again, EOF to quit."); 986 password = NULL; 987 } 988 memset(retype, 0, strlen(retype)); 989 xfree(retype); 990 } 991 packet_put_cstring(password); 992 memset(password, 0, strlen(password)); 993 xfree(password); 994 packet_add_padding(64); 995 packet_send(); 996 997 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 998 &input_userauth_passwd_changereq); 999} 1000 1001#ifdef JPAKE 1002static char * 1003pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 1004{ 1005 /* OpenBSD crypt(3) handles all of these */ 1006 if (strcmp(crypt_scheme, "crypt") == 0 || 1007 strcmp(crypt_scheme, "bcrypt") == 0 || 1008 strcmp(crypt_scheme, "md5crypt") == 0 || 1009 strcmp(crypt_scheme, "crypt-extended") == 0) 1010 return xstrdup(crypt(password, salt)); 1011 error("%s: unsupported password encryption scheme \"%.100s\"", 1012 __func__, crypt_scheme); 1013 return NULL; 1014} 1015 1016static BIGNUM * 1017jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 1018 const char *salt) 1019{ 1020 char prompt[256], *password, *crypted; 1021 u_char *secret; 1022 u_int secret_len; 1023 BIGNUM *ret; 1024 1025 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 1026 authctxt->server_user, authctxt->host); 1027 password = read_passphrase(prompt, 0); 1028 1029 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 1030 logit("Disabling %s authentication", authctxt->method->name); 1031 authctxt->method->enabled = NULL; 1032 /* Continue with an empty password to fail gracefully */ 1033 crypted = xstrdup(""); 1034 } 1035 1036#ifdef JPAKE_DEBUG 1037 debug3("%s: salt = %s", __func__, salt); 1038 debug3("%s: scheme = %s", __func__, crypt_scheme); 1039 debug3("%s: crypted = %s", __func__, crypted); 1040#endif 1041 1042 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 1043 &secret, &secret_len) != 0) 1044 fatal("%s: hash_buffer", __func__); 1045 1046 bzero(password, strlen(password)); 1047 bzero(crypted, strlen(crypted)); 1048 xfree(password); 1049 xfree(crypted); 1050 1051 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 1052 fatal("%s: BN_bin2bn (secret)", __func__); 1053 bzero(secret, secret_len); 1054 xfree(secret); 1055 1056 return ret; 1057} 1058 1059/* ARGSUSED */ 1060void 1061input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 1062{ 1063 Authctxt *authctxt = ctxt; 1064 struct jpake_ctx *pctx = authctxt->methoddata; 1065 u_char *x3_proof, *x4_proof, *x2_s_proof; 1066 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 1067 char *crypt_scheme, *salt; 1068 1069 /* Disable this message */ 1070 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 1071 1072 if ((pctx->g_x3 = BN_new()) == NULL || 1073 (pctx->g_x4 = BN_new()) == NULL) 1074 fatal("%s: BN_new", __func__); 1075 1076 /* Fetch step 1 values */ 1077 crypt_scheme = packet_get_string(NULL); 1078 salt = packet_get_string(NULL); 1079 pctx->server_id = packet_get_string(&pctx->server_id_len); 1080 packet_get_bignum2(pctx->g_x3); 1081 packet_get_bignum2(pctx->g_x4); 1082 x3_proof = packet_get_string(&x3_proof_len); 1083 x4_proof = packet_get_string(&x4_proof_len); 1084 packet_check_eom(); 1085 1086 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1087 1088 /* Obtain password and derive secret */ 1089 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1090 bzero(crypt_scheme, strlen(crypt_scheme)); 1091 bzero(salt, strlen(salt)); 1092 xfree(crypt_scheme); 1093 xfree(salt); 1094 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1095 1096 /* Calculate step 2 values */ 1097 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1098 pctx->g_x3, pctx->g_x4, pctx->x2, 1099 pctx->server_id, pctx->server_id_len, 1100 pctx->client_id, pctx->client_id_len, 1101 x3_proof, x3_proof_len, 1102 x4_proof, x4_proof_len, 1103 &pctx->a, 1104 &x2_s_proof, &x2_s_proof_len); 1105 1106 bzero(x3_proof, x3_proof_len); 1107 bzero(x4_proof, x4_proof_len); 1108 xfree(x3_proof); 1109 xfree(x4_proof); 1110 1111 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1112 1113 /* Send values for step 2 */ 1114 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1115 packet_put_bignum2(pctx->a); 1116 packet_put_string(x2_s_proof, x2_s_proof_len); 1117 packet_send(); 1118 1119 bzero(x2_s_proof, x2_s_proof_len); 1120 xfree(x2_s_proof); 1121 1122 /* Expect step 2 packet from peer */ 1123 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1124 input_userauth_jpake_server_step2); 1125} 1126 1127/* ARGSUSED */ 1128void 1129input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1130{ 1131 Authctxt *authctxt = ctxt; 1132 struct jpake_ctx *pctx = authctxt->methoddata; 1133 u_char *x4_s_proof; 1134 u_int x4_s_proof_len; 1135 1136 /* Disable this message */ 1137 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1138 1139 if ((pctx->b = BN_new()) == NULL) 1140 fatal("%s: BN_new", __func__); 1141 1142 /* Fetch step 2 values */ 1143 packet_get_bignum2(pctx->b); 1144 x4_s_proof = packet_get_string(&x4_s_proof_len); 1145 packet_check_eom(); 1146 1147 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1148 1149 /* Derive shared key and calculate confirmation hash */ 1150 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1151 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1152 pctx->client_id, pctx->client_id_len, 1153 pctx->server_id, pctx->server_id_len, 1154 session_id2, session_id2_len, 1155 x4_s_proof, x4_s_proof_len, 1156 &pctx->k, 1157 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1158 1159 bzero(x4_s_proof, x4_s_proof_len); 1160 xfree(x4_s_proof); 1161 1162 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1163 1164 /* Send key confirmation proof */ 1165 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1166 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1167 packet_send(); 1168 1169 /* Expect confirmation from peer */ 1170 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1171 input_userauth_jpake_server_confirm); 1172} 1173 1174/* ARGSUSED */ 1175void 1176input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1177{ 1178 Authctxt *authctxt = ctxt; 1179 struct jpake_ctx *pctx = authctxt->methoddata; 1180 1181 /* Disable this message */ 1182 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1183 1184 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1185 packet_check_eom(); 1186 1187 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1188 1189 /* Verify expected confirmation hash */ 1190 if (jpake_check_confirm(pctx->k, 1191 pctx->server_id, pctx->server_id_len, 1192 session_id2, session_id2_len, 1193 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1194 debug("%s: %s success", __func__, authctxt->method->name); 1195 else { 1196 debug("%s: confirmation mismatch", __func__); 1197 /* XXX stash this so if auth succeeds then we can warn/kill */ 1198 } 1199 1200 userauth_jpake_cleanup(authctxt); 1201} 1202#endif /* JPAKE */ 1203 1204static int 1205identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1206 u_char *data, u_int datalen) 1207{ 1208 Key *prv; 1209 int ret; 1210 1211 /* the agent supports this key */ 1212 if (id->ac) 1213 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1214 data, datalen)); 1215 /* 1216 * we have already loaded the private key or 1217 * the private key is stored in external hardware 1218 */ 1219 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1220 return (key_sign(id->key, sigp, lenp, data, datalen)); 1221 /* load the private key from the file */ 1222 if ((prv = load_identity_file(id->filename)) == NULL) 1223 return (-1); 1224 ret = key_sign(prv, sigp, lenp, data, datalen); 1225 key_free(prv); 1226 return (ret); 1227} 1228 1229static int 1230sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1231{ 1232 Buffer b; 1233 u_char *blob, *signature; 1234 u_int bloblen, slen; 1235 u_int skip = 0; 1236 int ret = -1; 1237 int have_sig = 1; 1238 char *fp; 1239 1240 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1241 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1242 xfree(fp); 1243 1244 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1245 /* we cannot handle this key */ 1246 debug3("sign_and_send_pubkey: cannot handle key"); 1247 return 0; 1248 } 1249 /* data to be signed */ 1250 buffer_init(&b); 1251 if (datafellows & SSH_OLD_SESSIONID) { 1252 buffer_append(&b, session_id2, session_id2_len); 1253 skip = session_id2_len; 1254 } else { 1255 buffer_put_string(&b, session_id2, session_id2_len); 1256 skip = buffer_len(&b); 1257 } 1258 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1259 buffer_put_cstring(&b, authctxt->server_user); 1260 buffer_put_cstring(&b, 1261 datafellows & SSH_BUG_PKSERVICE ? 1262 "ssh-userauth" : 1263 authctxt->service); 1264 if (datafellows & SSH_BUG_PKAUTH) { 1265 buffer_put_char(&b, have_sig); 1266 } else { 1267 buffer_put_cstring(&b, authctxt->method->name); 1268 buffer_put_char(&b, have_sig); 1269 buffer_put_cstring(&b, key_ssh_name(id->key)); 1270 } 1271 buffer_put_string(&b, blob, bloblen); 1272 1273 /* generate signature */ 1274 ret = identity_sign(id, &signature, &slen, 1275 buffer_ptr(&b), buffer_len(&b)); 1276 if (ret == -1) { 1277 xfree(blob); 1278 buffer_free(&b); 1279 return 0; 1280 } 1281#ifdef DEBUG_PK 1282 buffer_dump(&b); 1283#endif 1284 if (datafellows & SSH_BUG_PKSERVICE) { 1285 buffer_clear(&b); 1286 buffer_append(&b, session_id2, session_id2_len); 1287 skip = session_id2_len; 1288 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1289 buffer_put_cstring(&b, authctxt->server_user); 1290 buffer_put_cstring(&b, authctxt->service); 1291 buffer_put_cstring(&b, authctxt->method->name); 1292 buffer_put_char(&b, have_sig); 1293 if (!(datafellows & SSH_BUG_PKAUTH)) 1294 buffer_put_cstring(&b, key_ssh_name(id->key)); 1295 buffer_put_string(&b, blob, bloblen); 1296 } 1297 xfree(blob); 1298 1299 /* append signature */ 1300 buffer_put_string(&b, signature, slen); 1301 xfree(signature); 1302 1303 /* skip session id and packet type */ 1304 if (buffer_len(&b) < skip + 1) 1305 fatal("userauth_pubkey: internal error"); 1306 buffer_consume(&b, skip + 1); 1307 1308 /* put remaining data from buffer into packet */ 1309 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1310 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1311 buffer_free(&b); 1312 packet_send(); 1313 1314 return 1; 1315} 1316 1317static int 1318send_pubkey_test(Authctxt *authctxt, Identity *id) 1319{ 1320 u_char *blob; 1321 u_int bloblen, have_sig = 0; 1322 1323 debug3("send_pubkey_test"); 1324 1325 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1326 /* we cannot handle this key */ 1327 debug3("send_pubkey_test: cannot handle key"); 1328 return 0; 1329 } 1330 /* register callback for USERAUTH_PK_OK message */ 1331 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1332 1333 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1334 packet_put_cstring(authctxt->server_user); 1335 packet_put_cstring(authctxt->service); 1336 packet_put_cstring(authctxt->method->name); 1337 packet_put_char(have_sig); 1338 if (!(datafellows & SSH_BUG_PKAUTH)) 1339 packet_put_cstring(key_ssh_name(id->key)); 1340 packet_put_string(blob, bloblen); 1341 xfree(blob); 1342 packet_send(); 1343 return 1; 1344} 1345 1346static Key * 1347load_identity_file(char *filename) 1348{ 1349 Key *private; 1350 char prompt[300], *passphrase; 1351 int perm_ok = 0, quit, i; 1352 struct stat st; 1353 1354 if (stat(filename, &st) < 0) { 1355 debug3("no such identity: %s", filename); 1356 return NULL; 1357 } 1358 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1359 if (!perm_ok) 1360 return NULL; 1361 if (private == NULL) { 1362 if (options.batch_mode) 1363 return NULL; 1364 snprintf(prompt, sizeof prompt, 1365 "Enter passphrase for key '%.100s': ", filename); 1366 for (i = 0; i < options.number_of_password_prompts; i++) { 1367 passphrase = read_passphrase(prompt, 0); 1368 if (strcmp(passphrase, "") != 0) { 1369 private = key_load_private_type(KEY_UNSPEC, 1370 filename, passphrase, NULL, NULL); 1371 quit = 0; 1372 } else { 1373 debug2("no passphrase given, try next key"); 1374 quit = 1; 1375 } 1376 memset(passphrase, 0, strlen(passphrase)); 1377 xfree(passphrase); 1378 if (private != NULL || quit) 1379 break; 1380 debug2("bad passphrase given, try again..."); 1381 } 1382 } 1383 return private; 1384} 1385 1386/* 1387 * try keys in the following order: 1388 * 1. agent keys that are found in the config file 1389 * 2. other agent keys 1390 * 3. keys that are only listed in the config file 1391 */ 1392static void 1393pubkey_prepare(Authctxt *authctxt) 1394{ 1395 Identity *id; 1396 Idlist agent, files, *preferred; 1397 Key *key; 1398 AuthenticationConnection *ac; 1399 char *comment; 1400 int i, found; 1401 1402 TAILQ_INIT(&agent); /* keys from the agent */ 1403 TAILQ_INIT(&files); /* keys from the config file */ 1404 preferred = &authctxt->keys; 1405 TAILQ_INIT(preferred); /* preferred order of keys */ 1406 1407 /* list of keys stored in the filesystem */ 1408 for (i = 0; i < options.num_identity_files; i++) { 1409 key = options.identity_keys[i]; 1410 if (key && key->type == KEY_RSA1) 1411 continue; 1412 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1413 continue; 1414 options.identity_keys[i] = NULL; 1415 id = xcalloc(1, sizeof(*id)); 1416 id->key = key; 1417 id->filename = xstrdup(options.identity_files[i]); 1418 TAILQ_INSERT_TAIL(&files, id, next); 1419 } 1420 /* list of keys supported by the agent */ 1421 if ((ac = ssh_get_authentication_connection())) { 1422 for (key = ssh_get_first_identity(ac, &comment, 2); 1423 key != NULL; 1424 key = ssh_get_next_identity(ac, &comment, 2)) { 1425 found = 0; 1426 TAILQ_FOREACH(id, &files, next) { 1427 /* agent keys from the config file are preferred */ 1428 if (key_equal(key, id->key)) { 1429 key_free(key); 1430 xfree(comment); 1431 TAILQ_REMOVE(&files, id, next); 1432 TAILQ_INSERT_TAIL(preferred, id, next); 1433 id->ac = ac; 1434 found = 1; 1435 break; 1436 } 1437 } 1438 if (!found && !options.identities_only) { 1439 id = xcalloc(1, sizeof(*id)); 1440 id->key = key; 1441 id->filename = comment; 1442 id->ac = ac; 1443 TAILQ_INSERT_TAIL(&agent, id, next); 1444 } 1445 } 1446 /* append remaining agent keys */ 1447 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1448 TAILQ_REMOVE(&agent, id, next); 1449 TAILQ_INSERT_TAIL(preferred, id, next); 1450 } 1451 authctxt->agent = ac; 1452 } 1453 /* append remaining keys from the config file */ 1454 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1455 TAILQ_REMOVE(&files, id, next); 1456 TAILQ_INSERT_TAIL(preferred, id, next); 1457 } 1458 TAILQ_FOREACH(id, preferred, next) { 1459 debug2("key: %s (%p)", id->filename, id->key); 1460 } 1461} 1462 1463static void 1464pubkey_cleanup(Authctxt *authctxt) 1465{ 1466 Identity *id; 1467 1468 if (authctxt->agent != NULL) 1469 ssh_close_authentication_connection(authctxt->agent); 1470 for (id = TAILQ_FIRST(&authctxt->keys); id; 1471 id = TAILQ_FIRST(&authctxt->keys)) { 1472 TAILQ_REMOVE(&authctxt->keys, id, next); 1473 if (id->key) 1474 key_free(id->key); 1475 if (id->filename) 1476 xfree(id->filename); 1477 xfree(id); 1478 } 1479} 1480 1481int 1482userauth_pubkey(Authctxt *authctxt) 1483{ 1484 Identity *id; 1485 int sent = 0; 1486 1487 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1488 if (id->tried++) 1489 return (0); 1490 /* move key to the end of the queue */ 1491 TAILQ_REMOVE(&authctxt->keys, id, next); 1492 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1493 /* 1494 * send a test message if we have the public key. for 1495 * encrypted keys we cannot do this and have to load the 1496 * private key instead 1497 */ 1498 if (id->key && id->key->type != KEY_RSA1) { 1499 debug("Offering %s public key: %s", key_type(id->key), 1500 id->filename); 1501 sent = send_pubkey_test(authctxt, id); 1502 } else if (id->key == NULL) { 1503 debug("Trying private key: %s", id->filename); 1504 id->key = load_identity_file(id->filename); 1505 if (id->key != NULL) { 1506 id->isprivate = 1; 1507 sent = sign_and_send_pubkey(authctxt, id); 1508 key_free(id->key); 1509 id->key = NULL; 1510 } 1511 } 1512 if (sent) 1513 return (sent); 1514 } 1515 return (0); 1516} 1517 1518/* 1519 * Send userauth request message specifying keyboard-interactive method. 1520 */ 1521int 1522userauth_kbdint(Authctxt *authctxt) 1523{ 1524 static int attempt = 0; 1525 1526 if (attempt++ >= options.number_of_password_prompts) 1527 return 0; 1528 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1529 if (attempt > 1 && !authctxt->info_req_seen) { 1530 debug3("userauth_kbdint: disable: no info_req_seen"); 1531 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1532 return 0; 1533 } 1534 1535 debug2("userauth_kbdint"); 1536 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1537 packet_put_cstring(authctxt->server_user); 1538 packet_put_cstring(authctxt->service); 1539 packet_put_cstring(authctxt->method->name); 1540 packet_put_cstring(""); /* lang */ 1541 packet_put_cstring(options.kbd_interactive_devices ? 1542 options.kbd_interactive_devices : ""); 1543 packet_send(); 1544 1545 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1546 return 1; 1547} 1548 1549/* 1550 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1551 */ 1552void 1553input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1554{ 1555 Authctxt *authctxt = ctxt; 1556 char *name, *inst, *lang, *prompt, *response; 1557 u_int num_prompts, i; 1558 int echo = 0; 1559 1560 debug2("input_userauth_info_req"); 1561 1562 if (authctxt == NULL) 1563 fatal("input_userauth_info_req: no authentication context"); 1564 1565 authctxt->info_req_seen = 1; 1566 1567 name = packet_get_string(NULL); 1568 inst = packet_get_string(NULL); 1569 lang = packet_get_string(NULL); 1570 if (strlen(name) > 0) 1571 logit("%s", name); 1572 if (strlen(inst) > 0) 1573 logit("%s", inst); 1574 xfree(name); 1575 xfree(inst); 1576 xfree(lang); 1577 1578 num_prompts = packet_get_int(); 1579 /* 1580 * Begin to build info response packet based on prompts requested. 1581 * We commit to providing the correct number of responses, so if 1582 * further on we run into a problem that prevents this, we have to 1583 * be sure and clean this up and send a correct error response. 1584 */ 1585 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1586 packet_put_int(num_prompts); 1587 1588 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1589 for (i = 0; i < num_prompts; i++) { 1590 prompt = packet_get_string(NULL); 1591 echo = packet_get_char(); 1592 1593 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1594 1595 packet_put_cstring(response); 1596 memset(response, 0, strlen(response)); 1597 xfree(response); 1598 xfree(prompt); 1599 } 1600 packet_check_eom(); /* done with parsing incoming message. */ 1601 1602 packet_add_padding(64); 1603 packet_send(); 1604} 1605 1606static int 1607ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1608 u_char *data, u_int datalen) 1609{ 1610 Buffer b; 1611 struct stat st; 1612 pid_t pid; 1613 int to[2], from[2], status, version = 2; 1614 1615 debug2("ssh_keysign called"); 1616 1617 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1618 error("ssh_keysign: not installed: %s", strerror(errno)); 1619 return -1; 1620 } 1621 if (fflush(stdout) != 0) 1622 error("ssh_keysign: fflush: %s", strerror(errno)); 1623 if (pipe(to) < 0) { 1624 error("ssh_keysign: pipe: %s", strerror(errno)); 1625 return -1; 1626 } 1627 if (pipe(from) < 0) { 1628 error("ssh_keysign: pipe: %s", strerror(errno)); 1629 return -1; 1630 } 1631 if ((pid = fork()) < 0) { 1632 error("ssh_keysign: fork: %s", strerror(errno)); 1633 return -1; 1634 } 1635 if (pid == 0) { 1636 /* keep the socket on exec */ 1637 fcntl(packet_get_connection_in(), F_SETFD, 0); 1638 permanently_drop_suid(getuid()); 1639 close(from[0]); 1640 if (dup2(from[1], STDOUT_FILENO) < 0) 1641 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1642 close(to[1]); 1643 if (dup2(to[0], STDIN_FILENO) < 0) 1644 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1645 close(from[1]); 1646 close(to[0]); 1647 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1648 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1649 strerror(errno)); 1650 } 1651 close(from[1]); 1652 close(to[0]); 1653 1654 buffer_init(&b); 1655 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1656 buffer_put_string(&b, data, datalen); 1657 if (ssh_msg_send(to[1], version, &b) == -1) 1658 fatal("ssh_keysign: couldn't send request"); 1659 1660 if (ssh_msg_recv(from[0], &b) < 0) { 1661 error("ssh_keysign: no reply"); 1662 buffer_free(&b); 1663 return -1; 1664 } 1665 close(from[0]); 1666 close(to[1]); 1667 1668 while (waitpid(pid, &status, 0) < 0) 1669 if (errno != EINTR) 1670 break; 1671 1672 if (buffer_get_char(&b) != version) { 1673 error("ssh_keysign: bad version"); 1674 buffer_free(&b); 1675 return -1; 1676 } 1677 *sigp = buffer_get_string(&b, lenp); 1678 buffer_free(&b); 1679 1680 return 0; 1681} 1682 1683int 1684userauth_hostbased(Authctxt *authctxt) 1685{ 1686 Key *private = NULL; 1687 Sensitive *sensitive = authctxt->sensitive; 1688 Buffer b; 1689 u_char *signature, *blob; 1690 char *chost, *pkalg, *p; 1691 const char *service; 1692 u_int blen, slen; 1693 int ok, i, found = 0; 1694 1695 /* check for a useful key */ 1696 for (i = 0; i < sensitive->nkeys; i++) { 1697 private = sensitive->keys[i]; 1698 if (private && private->type != KEY_RSA1) { 1699 found = 1; 1700 /* we take and free the key */ 1701 sensitive->keys[i] = NULL; 1702 break; 1703 } 1704 } 1705 if (!found) { 1706 debug("No more client hostkeys for hostbased authentication."); 1707 return 0; 1708 } 1709 if (key_to_blob(private, &blob, &blen) == 0) { 1710 key_free(private); 1711 return 0; 1712 } 1713 /* figure out a name for the client host */ 1714 p = get_local_name(packet_get_connection_in()); 1715 if (p == NULL) { 1716 error("userauth_hostbased: cannot get local ipaddr/name"); 1717 key_free(private); 1718 xfree(blob); 1719 return 0; 1720 } 1721 xasprintf(&chost, "%s.", p); 1722 debug2("userauth_hostbased: chost %s", chost); 1723 xfree(p); 1724 1725 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1726 authctxt->service; 1727 pkalg = xstrdup(key_ssh_name(private)); 1728 buffer_init(&b); 1729 /* construct data */ 1730 buffer_put_string(&b, session_id2, session_id2_len); 1731 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1732 buffer_put_cstring(&b, authctxt->server_user); 1733 buffer_put_cstring(&b, service); 1734 buffer_put_cstring(&b, authctxt->method->name); 1735 buffer_put_cstring(&b, pkalg); 1736 buffer_put_string(&b, blob, blen); 1737 buffer_put_cstring(&b, chost); 1738 buffer_put_cstring(&b, authctxt->local_user); 1739#ifdef DEBUG_PK 1740 buffer_dump(&b); 1741#endif 1742 if (sensitive->external_keysign) 1743 ok = ssh_keysign(private, &signature, &slen, 1744 buffer_ptr(&b), buffer_len(&b)); 1745 else 1746 ok = key_sign(private, &signature, &slen, 1747 buffer_ptr(&b), buffer_len(&b)); 1748 key_free(private); 1749 buffer_free(&b); 1750 if (ok != 0) { 1751 error("key_sign failed"); 1752 xfree(chost); 1753 xfree(pkalg); 1754 xfree(blob); 1755 return 0; 1756 } 1757 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1758 packet_put_cstring(authctxt->server_user); 1759 packet_put_cstring(authctxt->service); 1760 packet_put_cstring(authctxt->method->name); 1761 packet_put_cstring(pkalg); 1762 packet_put_string(blob, blen); 1763 packet_put_cstring(chost); 1764 packet_put_cstring(authctxt->local_user); 1765 packet_put_string(signature, slen); 1766 memset(signature, 's', slen); 1767 xfree(signature); 1768 xfree(chost); 1769 xfree(pkalg); 1770 xfree(blob); 1771 1772 packet_send(); 1773 return 1; 1774} 1775 1776#ifdef JPAKE 1777int 1778userauth_jpake(Authctxt *authctxt) 1779{ 1780 struct jpake_ctx *pctx; 1781 u_char *x1_proof, *x2_proof; 1782 u_int x1_proof_len, x2_proof_len; 1783 static int attempt = 0; /* XXX share with userauth_password's? */ 1784 1785 if (attempt++ >= options.number_of_password_prompts) 1786 return 0; 1787 if (attempt != 1) 1788 error("Permission denied, please try again."); 1789 1790 if (authctxt->methoddata != NULL) 1791 fatal("%s: authctxt->methoddata already set (%p)", 1792 __func__, authctxt->methoddata); 1793 1794 authctxt->methoddata = pctx = jpake_new(); 1795 1796 /* 1797 * Send request immediately, to get the protocol going while 1798 * we do the initial computations. 1799 */ 1800 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1801 packet_put_cstring(authctxt->server_user); 1802 packet_put_cstring(authctxt->service); 1803 packet_put_cstring(authctxt->method->name); 1804 packet_send(); 1805 packet_write_wait(); 1806 1807 jpake_step1(pctx->grp, 1808 &pctx->client_id, &pctx->client_id_len, 1809 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1810 &x1_proof, &x1_proof_len, 1811 &x2_proof, &x2_proof_len); 1812 1813 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1814 1815 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1816 packet_put_string(pctx->client_id, pctx->client_id_len); 1817 packet_put_bignum2(pctx->g_x1); 1818 packet_put_bignum2(pctx->g_x2); 1819 packet_put_string(x1_proof, x1_proof_len); 1820 packet_put_string(x2_proof, x2_proof_len); 1821 packet_send(); 1822 1823 bzero(x1_proof, x1_proof_len); 1824 bzero(x2_proof, x2_proof_len); 1825 xfree(x1_proof); 1826 xfree(x2_proof); 1827 1828 /* Expect step 1 packet from peer */ 1829 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1830 input_userauth_jpake_server_step1); 1831 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1832 &input_userauth_success_unexpected); 1833 1834 return 1; 1835} 1836 1837void 1838userauth_jpake_cleanup(Authctxt *authctxt) 1839{ 1840 debug3("%s: clean up", __func__); 1841 if (authctxt->methoddata != NULL) { 1842 jpake_free(authctxt->methoddata); 1843 authctxt->methoddata = NULL; 1844 } 1845 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1846} 1847#endif /* JPAKE */ 1848 1849/* find auth method */ 1850 1851/* 1852 * given auth method name, if configurable options permit this method fill 1853 * in auth_ident field and return true, otherwise return false. 1854 */ 1855static int 1856authmethod_is_enabled(Authmethod *method) 1857{ 1858 if (method == NULL) 1859 return 0; 1860 /* return false if options indicate this method is disabled */ 1861 if (method->enabled == NULL || *method->enabled == 0) 1862 return 0; 1863 /* return false if batch mode is enabled but method needs interactive mode */ 1864 if (method->batch_flag != NULL && *method->batch_flag != 0) 1865 return 0; 1866 return 1; 1867} 1868 1869static Authmethod * 1870authmethod_lookup(const char *name) 1871{ 1872 Authmethod *method = NULL; 1873 if (name != NULL) 1874 for (method = authmethods; method->name != NULL; method++) 1875 if (strcmp(name, method->name) == 0) 1876 return method; 1877 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1878 return NULL; 1879} 1880 1881/* XXX internal state */ 1882static Authmethod *current = NULL; 1883static char *supported = NULL; 1884static char *preferred = NULL; 1885 1886/* 1887 * Given the authentication method list sent by the server, return the 1888 * next method we should try. If the server initially sends a nil list, 1889 * use a built-in default list. 1890 */ 1891static Authmethod * 1892authmethod_get(char *authlist) 1893{ 1894 char *name = NULL; 1895 u_int next; 1896 1897 /* Use a suitable default if we're passed a nil list. */ 1898 if (authlist == NULL || strlen(authlist) == 0) 1899 authlist = options.preferred_authentications; 1900 1901 if (supported == NULL || strcmp(authlist, supported) != 0) { 1902 debug3("start over, passed a different list %s", authlist); 1903 if (supported != NULL) 1904 xfree(supported); 1905 supported = xstrdup(authlist); 1906 preferred = options.preferred_authentications; 1907 debug3("preferred %s", preferred); 1908 current = NULL; 1909 } else if (current != NULL && authmethod_is_enabled(current)) 1910 return current; 1911 1912 for (;;) { 1913 if ((name = match_list(preferred, supported, &next)) == NULL) { 1914 debug("No more authentication methods to try."); 1915 current = NULL; 1916 return NULL; 1917 } 1918 preferred += next; 1919 debug3("authmethod_lookup %s", name); 1920 debug3("remaining preferred: %s", preferred); 1921 if ((current = authmethod_lookup(name)) != NULL && 1922 authmethod_is_enabled(current)) { 1923 debug3("authmethod_is_enabled %s", name); 1924 debug("Next authentication method: %s", name); 1925 return current; 1926 } 1927 } 1928} 1929 1930static char * 1931authmethods_get(void) 1932{ 1933 Authmethod *method = NULL; 1934 Buffer b; 1935 char *list; 1936 1937 buffer_init(&b); 1938 for (method = authmethods; method->name != NULL; method++) { 1939 if (authmethod_is_enabled(method)) { 1940 if (buffer_len(&b) > 0) 1941 buffer_append(&b, ",", 1); 1942 buffer_append(&b, method->name, strlen(method->name)); 1943 } 1944 } 1945 buffer_append(&b, "\0", 1); 1946 list = xstrdup(buffer_ptr(&b)); 1947 buffer_free(&b); 1948 return list; 1949} 1950 1951