sshconnect2.c revision 226046
1/* $OpenBSD: sshconnect2.c,v 1.188 2011/05/24 07:15:47 djm Exp $ */ 2/* $FreeBSD: head/crypto/openssh/sshconnect2.c 226046 2011-10-05 22:08:17Z des $ */ 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 u_int i; 124 125 /* Find all hostkeys for this hostname */ 126 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 127 hostkeys = init_hostkeys(); 128 for (i = 0; i < options.num_user_hostfiles; i++) 129 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 130 for (i = 0; i < options.num_system_hostfiles; i++) 131 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 132 133 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 134 maxlen = strlen(avail) + 1; 135 first = xmalloc(maxlen); 136 last = xmalloc(maxlen); 137 *first = *last = '\0'; 138 139#define ALG_APPEND(to, from) \ 140 do { \ 141 if (*to != '\0') \ 142 strlcat(to, ",", maxlen); \ 143 strlcat(to, from, maxlen); \ 144 } while (0) 145 146 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 147 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) 148 fatal("%s: unknown alg %s", __func__, alg); 149 if (lookup_key_in_hostkeys_by_type(hostkeys, 150 key_type_plain(ktype), NULL)) 151 ALG_APPEND(first, alg); 152 else 153 ALG_APPEND(last, alg); 154 } 155#undef ALG_APPEND 156 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); 157 if (*first != '\0') 158 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 159 160 xfree(first); 161 xfree(last); 162 xfree(hostname); 163 xfree(oavail); 164 free_hostkeys(hostkeys); 165 166 return ret; 167} 168 169void 170ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 171{ 172 Kex *kex; 173 174 xxx_host = host; 175 xxx_hostaddr = hostaddr; 176 177 if (options.ciphers == (char *)-1) { 178 logit("No valid ciphers for protocol version 2 given, using defaults."); 179 options.ciphers = NULL; 180 } 181 if (options.ciphers != NULL) { 182 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 183 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 184 } 185 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 186 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 187 myproposal[PROPOSAL_ENC_ALGS_STOC] = 188 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 189 if (options.compression) { 190 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 191 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 192 } else { 193 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 194 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 195 } 196 if (options.macs != NULL) { 197 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 198 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 199 } 200 if (options.hostkeyalgorithms != NULL) 201 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 202 options.hostkeyalgorithms; 203 else { 204 /* Prefer algorithms that we already have keys for */ 205 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 206 order_hostkeyalgs(host, hostaddr, port); 207 } 208 if (options.kex_algorithms != NULL) 209 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 210 211 if (options.rekey_limit) 212 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 213 214 /* start key exchange */ 215 kex = kex_setup(myproposal); 216 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 217 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 218 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 219 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 220 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 221 kex->client_version_string=client_version_string; 222 kex->server_version_string=server_version_string; 223 kex->verify_host_key=&verify_host_key_callback; 224 225 xxx_kex = kex; 226 227 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 228 229 if (options.use_roaming && !kex->roaming) { 230 debug("Roaming not allowed by server"); 231 options.use_roaming = 0; 232 } 233 234 session_id2 = kex->session_id; 235 session_id2_len = kex->session_id_len; 236 237#ifdef DEBUG_KEXDH 238 /* send 1st encrypted/maced/compressed message */ 239 packet_start(SSH2_MSG_IGNORE); 240 packet_put_cstring("markus"); 241 packet_send(); 242 packet_write_wait(); 243#endif 244} 245 246/* 247 * Authenticate user 248 */ 249 250typedef struct Authctxt Authctxt; 251typedef struct Authmethod Authmethod; 252typedef struct identity Identity; 253typedef struct idlist Idlist; 254 255struct identity { 256 TAILQ_ENTRY(identity) next; 257 AuthenticationConnection *ac; /* set if agent supports key */ 258 Key *key; /* public/private key */ 259 char *filename; /* comment for agent-only keys */ 260 int tried; 261 int isprivate; /* key points to the private key */ 262}; 263TAILQ_HEAD(idlist, identity); 264 265struct Authctxt { 266 const char *server_user; 267 const char *local_user; 268 const char *host; 269 const char *service; 270 Authmethod *method; 271 sig_atomic_t success; 272 char *authlist; 273 /* pubkey */ 274 Idlist keys; 275 AuthenticationConnection *agent; 276 /* hostbased */ 277 Sensitive *sensitive; 278 /* kbd-interactive */ 279 int info_req_seen; 280 /* generic */ 281 void *methoddata; 282}; 283struct Authmethod { 284 char *name; /* string to compare against server's list */ 285 int (*userauth)(Authctxt *authctxt); 286 void (*cleanup)(Authctxt *authctxt); 287 int *enabled; /* flag in option struct that enables method */ 288 int *batch_flag; /* flag in option struct that disables method */ 289}; 290 291void input_userauth_success(int, u_int32_t, void *); 292void input_userauth_success_unexpected(int, u_int32_t, void *); 293void input_userauth_failure(int, u_int32_t, void *); 294void input_userauth_banner(int, u_int32_t, void *); 295void input_userauth_error(int, u_int32_t, void *); 296void input_userauth_info_req(int, u_int32_t, void *); 297void input_userauth_pk_ok(int, u_int32_t, void *); 298void input_userauth_passwd_changereq(int, u_int32_t, void *); 299void input_userauth_jpake_server_step1(int, u_int32_t, void *); 300void input_userauth_jpake_server_step2(int, u_int32_t, void *); 301void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 302 303int userauth_none(Authctxt *); 304int userauth_pubkey(Authctxt *); 305int userauth_passwd(Authctxt *); 306int userauth_kbdint(Authctxt *); 307int userauth_hostbased(Authctxt *); 308int userauth_jpake(Authctxt *); 309 310void userauth_jpake_cleanup(Authctxt *); 311 312#ifdef GSSAPI 313int userauth_gssapi(Authctxt *authctxt); 314void input_gssapi_response(int type, u_int32_t, void *); 315void input_gssapi_token(int type, u_int32_t, void *); 316void input_gssapi_hash(int type, u_int32_t, void *); 317void input_gssapi_error(int, u_int32_t, void *); 318void input_gssapi_errtok(int, u_int32_t, void *); 319#endif 320 321void userauth(Authctxt *, char *); 322 323static int sign_and_send_pubkey(Authctxt *, Identity *); 324static void pubkey_prepare(Authctxt *); 325static void pubkey_cleanup(Authctxt *); 326static Key *load_identity_file(char *); 327 328static Authmethod *authmethod_get(char *authlist); 329static Authmethod *authmethod_lookup(const char *name); 330static char *authmethods_get(void); 331 332Authmethod authmethods[] = { 333#ifdef GSSAPI 334 {"gssapi-with-mic", 335 userauth_gssapi, 336 NULL, 337 &options.gss_authentication, 338 NULL}, 339#endif 340 {"hostbased", 341 userauth_hostbased, 342 NULL, 343 &options.hostbased_authentication, 344 NULL}, 345 {"publickey", 346 userauth_pubkey, 347 NULL, 348 &options.pubkey_authentication, 349 NULL}, 350#ifdef JPAKE 351 {"jpake-01@openssh.com", 352 userauth_jpake, 353 userauth_jpake_cleanup, 354 &options.zero_knowledge_password_authentication, 355 &options.batch_mode}, 356#endif 357 {"keyboard-interactive", 358 userauth_kbdint, 359 NULL, 360 &options.kbd_interactive_authentication, 361 &options.batch_mode}, 362 {"password", 363 userauth_passwd, 364 NULL, 365 &options.password_authentication, 366 &options.batch_mode}, 367 {"none", 368 userauth_none, 369 NULL, 370 NULL, 371 NULL}, 372 {NULL, NULL, NULL, NULL, NULL} 373}; 374 375void 376ssh_userauth2(const char *local_user, const char *server_user, char *host, 377 Sensitive *sensitive) 378{ 379 Authctxt authctxt; 380 int type; 381 382 if (options.challenge_response_authentication) 383 options.kbd_interactive_authentication = 1; 384 385 packet_start(SSH2_MSG_SERVICE_REQUEST); 386 packet_put_cstring("ssh-userauth"); 387 packet_send(); 388 debug("SSH2_MSG_SERVICE_REQUEST sent"); 389 packet_write_wait(); 390 type = packet_read(); 391 if (type != SSH2_MSG_SERVICE_ACCEPT) 392 fatal("Server denied authentication request: %d", type); 393 if (packet_remaining() > 0) { 394 char *reply = packet_get_string(NULL); 395 debug2("service_accept: %s", reply); 396 xfree(reply); 397 } else { 398 debug2("buggy server: service_accept w/o service"); 399 } 400 packet_check_eom(); 401 debug("SSH2_MSG_SERVICE_ACCEPT received"); 402 403 if (options.preferred_authentications == NULL) 404 options.preferred_authentications = authmethods_get(); 405 406 /* setup authentication context */ 407 memset(&authctxt, 0, sizeof(authctxt)); 408 pubkey_prepare(&authctxt); 409 authctxt.server_user = server_user; 410 authctxt.local_user = local_user; 411 authctxt.host = host; 412 authctxt.service = "ssh-connection"; /* service name */ 413 authctxt.success = 0; 414 authctxt.method = authmethod_lookup("none"); 415 authctxt.authlist = NULL; 416 authctxt.methoddata = NULL; 417 authctxt.sensitive = sensitive; 418 authctxt.info_req_seen = 0; 419 if (authctxt.method == NULL) 420 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 421 422 /* initial userauth request */ 423 userauth_none(&authctxt); 424 425 dispatch_init(&input_userauth_error); 426 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 427 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 428 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 429 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 430 431 pubkey_cleanup(&authctxt); 432 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 433 434#ifdef NONE_CIPHER_ENABLED 435 /* 436 * If the user explicitly requests to use the none cipher enable it 437 * post authentication and only if the right conditions are met: both 438 * of the NONE switches must be true and there must be no tty allocated. 439 */ 440 if (options.none_switch == 1 && options.none_enabled == 1) { 441 if (!tty_flag) { 442 debug("Requesting none cipher re-keying..."); 443 myproposal[PROPOSAL_ENC_ALGS_STOC] = "none"; 444 myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none"; 445 kex_prop2buf(&xxx_kex->my, myproposal); 446 packet_request_rekeying(); 447 fprintf(stderr, "WARNING: enabled NONE cipher\n"); 448 } else { 449 /* Requested NONE cipher on an interactive session. */ 450 debug("Cannot switch to NONE cipher with tty " 451 "allocated"); 452 fprintf(stderr, "NONE cipher switch disabled given " 453 "a TTY is allocated\n"); 454 } 455 } 456#endif 457 debug("Authentication succeeded (%s).", authctxt.method->name); 458} 459 460void 461userauth(Authctxt *authctxt, char *authlist) 462{ 463 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 464 authctxt->method->cleanup(authctxt); 465 466 if (authctxt->methoddata) { 467 xfree(authctxt->methoddata); 468 authctxt->methoddata = NULL; 469 } 470 if (authlist == NULL) { 471 authlist = authctxt->authlist; 472 } else { 473 if (authctxt->authlist) 474 xfree(authctxt->authlist); 475 authctxt->authlist = authlist; 476 } 477 for (;;) { 478 Authmethod *method = authmethod_get(authlist); 479 if (method == NULL) 480 fatal("Permission denied (%s).", authlist); 481 authctxt->method = method; 482 483 /* reset the per method handler */ 484 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 485 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 486 487 /* and try new method */ 488 if (method->userauth(authctxt) != 0) { 489 debug2("we sent a %s packet, wait for reply", method->name); 490 break; 491 } else { 492 debug2("we did not send a packet, disable method"); 493 method->enabled = NULL; 494 } 495 } 496} 497 498/* ARGSUSED */ 499void 500input_userauth_error(int type, u_int32_t seq, void *ctxt) 501{ 502 fatal("input_userauth_error: bad message during authentication: " 503 "type %d", type); 504} 505 506/* ARGSUSED */ 507void 508input_userauth_banner(int type, u_int32_t seq, void *ctxt) 509{ 510 char *msg, *raw, *lang; 511 u_int len; 512 513 debug3("input_userauth_banner"); 514 raw = packet_get_string(&len); 515 lang = packet_get_string(NULL); 516 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 517 if (len > 65536) 518 len = 65536; 519 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 520 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 521 fprintf(stderr, "%s", msg); 522 xfree(msg); 523 } 524 xfree(raw); 525 xfree(lang); 526} 527 528/* ARGSUSED */ 529void 530input_userauth_success(int type, u_int32_t seq, void *ctxt) 531{ 532 Authctxt *authctxt = ctxt; 533 534 if (authctxt == NULL) 535 fatal("input_userauth_success: no authentication context"); 536 if (authctxt->authlist) { 537 xfree(authctxt->authlist); 538 authctxt->authlist = NULL; 539 } 540 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 541 authctxt->method->cleanup(authctxt); 542 if (authctxt->methoddata) { 543 xfree(authctxt->methoddata); 544 authctxt->methoddata = NULL; 545 } 546 authctxt->success = 1; /* break out */ 547} 548 549void 550input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 551{ 552 Authctxt *authctxt = ctxt; 553 554 if (authctxt == NULL) 555 fatal("%s: no authentication context", __func__); 556 557 fatal("Unexpected authentication success during %s.", 558 authctxt->method->name); 559} 560 561/* ARGSUSED */ 562void 563input_userauth_failure(int type, u_int32_t seq, void *ctxt) 564{ 565 Authctxt *authctxt = ctxt; 566 char *authlist = NULL; 567 int partial; 568 569 if (authctxt == NULL) 570 fatal("input_userauth_failure: no authentication context"); 571 572 authlist = packet_get_string(NULL); 573 partial = packet_get_char(); 574 packet_check_eom(); 575 576 if (partial != 0) 577 logit("Authenticated with partial success."); 578 debug("Authentications that can continue: %s", authlist); 579 580 userauth(authctxt, authlist); 581} 582 583/* ARGSUSED */ 584void 585input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 586{ 587 Authctxt *authctxt = ctxt; 588 Key *key = NULL; 589 Identity *id = NULL; 590 Buffer b; 591 int pktype, sent = 0; 592 u_int alen, blen; 593 char *pkalg, *fp; 594 u_char *pkblob; 595 596 if (authctxt == NULL) 597 fatal("input_userauth_pk_ok: no authentication context"); 598 if (datafellows & SSH_BUG_PKOK) { 599 /* this is similar to SSH_BUG_PKAUTH */ 600 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 601 pkblob = packet_get_string(&blen); 602 buffer_init(&b); 603 buffer_append(&b, pkblob, blen); 604 pkalg = buffer_get_string(&b, &alen); 605 buffer_free(&b); 606 } else { 607 pkalg = packet_get_string(&alen); 608 pkblob = packet_get_string(&blen); 609 } 610 packet_check_eom(); 611 612 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 613 614 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 615 debug("unknown pkalg %s", pkalg); 616 goto done; 617 } 618 if ((key = key_from_blob(pkblob, blen)) == NULL) { 619 debug("no key from blob. pkalg %s", pkalg); 620 goto done; 621 } 622 if (key->type != pktype) { 623 error("input_userauth_pk_ok: type mismatch " 624 "for decoded key (received %d, expected %d)", 625 key->type, pktype); 626 goto done; 627 } 628 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 629 debug2("input_userauth_pk_ok: fp %s", fp); 630 xfree(fp); 631 632 /* 633 * search keys in the reverse order, because last candidate has been 634 * moved to the end of the queue. this also avoids confusion by 635 * duplicate keys 636 */ 637 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 638 if (key_equal(key, id->key)) { 639 sent = sign_and_send_pubkey(authctxt, id); 640 break; 641 } 642 } 643done: 644 if (key != NULL) 645 key_free(key); 646 xfree(pkalg); 647 xfree(pkblob); 648 649 /* try another method if we did not send a packet */ 650 if (sent == 0) 651 userauth(authctxt, NULL); 652} 653 654#ifdef GSSAPI 655int 656userauth_gssapi(Authctxt *authctxt) 657{ 658 Gssctxt *gssctxt = NULL; 659 static gss_OID_set gss_supported = NULL; 660 static u_int mech = 0; 661 OM_uint32 min; 662 int ok = 0; 663 664 /* Try one GSSAPI method at a time, rather than sending them all at 665 * once. */ 666 667 if (gss_supported == NULL) 668 gss_indicate_mechs(&min, &gss_supported); 669 670 /* Check to see if the mechanism is usable before we offer it */ 671 while (mech < gss_supported->count && !ok) { 672 /* My DER encoding requires length<128 */ 673 if (gss_supported->elements[mech].length < 128 && 674 ssh_gssapi_check_mechanism(&gssctxt, 675 &gss_supported->elements[mech], authctxt->host)) { 676 ok = 1; /* Mechanism works */ 677 } else { 678 mech++; 679 } 680 } 681 682 if (!ok) 683 return 0; 684 685 authctxt->methoddata=(void *)gssctxt; 686 687 packet_start(SSH2_MSG_USERAUTH_REQUEST); 688 packet_put_cstring(authctxt->server_user); 689 packet_put_cstring(authctxt->service); 690 packet_put_cstring(authctxt->method->name); 691 692 packet_put_int(1); 693 694 packet_put_int((gss_supported->elements[mech].length) + 2); 695 packet_put_char(SSH_GSS_OIDTYPE); 696 packet_put_char(gss_supported->elements[mech].length); 697 packet_put_raw(gss_supported->elements[mech].elements, 698 gss_supported->elements[mech].length); 699 700 packet_send(); 701 702 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 703 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 704 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 705 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 706 707 mech++; /* Move along to next candidate */ 708 709 return 1; 710} 711 712static OM_uint32 713process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 714{ 715 Authctxt *authctxt = ctxt; 716 Gssctxt *gssctxt = authctxt->methoddata; 717 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 718 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 719 gss_buffer_desc gssbuf; 720 OM_uint32 status, ms, flags; 721 Buffer b; 722 723 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 724 recv_tok, &send_tok, &flags); 725 726 if (send_tok.length > 0) { 727 if (GSS_ERROR(status)) 728 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 729 else 730 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 731 732 packet_put_string(send_tok.value, send_tok.length); 733 packet_send(); 734 gss_release_buffer(&ms, &send_tok); 735 } 736 737 if (status == GSS_S_COMPLETE) { 738 /* send either complete or MIC, depending on mechanism */ 739 if (!(flags & GSS_C_INTEG_FLAG)) { 740 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 741 packet_send(); 742 } else { 743 ssh_gssapi_buildmic(&b, authctxt->server_user, 744 authctxt->service, "gssapi-with-mic"); 745 746 gssbuf.value = buffer_ptr(&b); 747 gssbuf.length = buffer_len(&b); 748 749 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 750 751 if (!GSS_ERROR(status)) { 752 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 753 packet_put_string(mic.value, mic.length); 754 755 packet_send(); 756 } 757 758 buffer_free(&b); 759 gss_release_buffer(&ms, &mic); 760 } 761 } 762 763 return status; 764} 765 766/* ARGSUSED */ 767void 768input_gssapi_response(int type, u_int32_t plen, void *ctxt) 769{ 770 Authctxt *authctxt = ctxt; 771 Gssctxt *gssctxt; 772 int oidlen; 773 char *oidv; 774 775 if (authctxt == NULL) 776 fatal("input_gssapi_response: no authentication context"); 777 gssctxt = authctxt->methoddata; 778 779 /* Setup our OID */ 780 oidv = packet_get_string(&oidlen); 781 782 if (oidlen <= 2 || 783 oidv[0] != SSH_GSS_OIDTYPE || 784 oidv[1] != oidlen - 2) { 785 xfree(oidv); 786 debug("Badly encoded mechanism OID received"); 787 userauth(authctxt, NULL); 788 return; 789 } 790 791 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 792 fatal("Server returned different OID than expected"); 793 794 packet_check_eom(); 795 796 xfree(oidv); 797 798 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 799 /* Start again with next method on list */ 800 debug("Trying to start again"); 801 userauth(authctxt, NULL); 802 return; 803 } 804} 805 806/* ARGSUSED */ 807void 808input_gssapi_token(int type, u_int32_t plen, void *ctxt) 809{ 810 Authctxt *authctxt = ctxt; 811 gss_buffer_desc recv_tok; 812 OM_uint32 status; 813 u_int slen; 814 815 if (authctxt == NULL) 816 fatal("input_gssapi_response: no authentication context"); 817 818 recv_tok.value = packet_get_string(&slen); 819 recv_tok.length = slen; /* safe typecast */ 820 821 packet_check_eom(); 822 823 status = process_gssapi_token(ctxt, &recv_tok); 824 825 xfree(recv_tok.value); 826 827 if (GSS_ERROR(status)) { 828 /* Start again with the next method in the list */ 829 userauth(authctxt, NULL); 830 return; 831 } 832} 833 834/* ARGSUSED */ 835void 836input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 837{ 838 Authctxt *authctxt = ctxt; 839 Gssctxt *gssctxt; 840 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 841 gss_buffer_desc recv_tok; 842 OM_uint32 status, ms; 843 u_int len; 844 845 if (authctxt == NULL) 846 fatal("input_gssapi_response: no authentication context"); 847 gssctxt = authctxt->methoddata; 848 849 recv_tok.value = packet_get_string(&len); 850 recv_tok.length = len; 851 852 packet_check_eom(); 853 854 /* Stick it into GSSAPI and see what it says */ 855 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 856 &recv_tok, &send_tok, NULL); 857 858 xfree(recv_tok.value); 859 gss_release_buffer(&ms, &send_tok); 860 861 /* Server will be returning a failed packet after this one */ 862} 863 864/* ARGSUSED */ 865void 866input_gssapi_error(int type, u_int32_t plen, void *ctxt) 867{ 868 OM_uint32 maj, min; 869 char *msg; 870 char *lang; 871 872 maj=packet_get_int(); 873 min=packet_get_int(); 874 msg=packet_get_string(NULL); 875 lang=packet_get_string(NULL); 876 877 packet_check_eom(); 878 879 debug("Server GSSAPI Error:\n%s", msg); 880 xfree(msg); 881 xfree(lang); 882} 883#endif /* GSSAPI */ 884 885int 886userauth_none(Authctxt *authctxt) 887{ 888 /* initial userauth request */ 889 packet_start(SSH2_MSG_USERAUTH_REQUEST); 890 packet_put_cstring(authctxt->server_user); 891 packet_put_cstring(authctxt->service); 892 packet_put_cstring(authctxt->method->name); 893 packet_send(); 894 return 1; 895} 896 897int 898userauth_passwd(Authctxt *authctxt) 899{ 900 static int attempt = 0; 901 char prompt[150]; 902 char *password; 903 const char *host = options.host_key_alias ? options.host_key_alias : 904 authctxt->host; 905 906 if (attempt++ >= options.number_of_password_prompts) 907 return 0; 908 909 if (attempt != 1) 910 error("Permission denied, please try again."); 911 912 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 913 authctxt->server_user, host); 914 password = read_passphrase(prompt, 0); 915 packet_start(SSH2_MSG_USERAUTH_REQUEST); 916 packet_put_cstring(authctxt->server_user); 917 packet_put_cstring(authctxt->service); 918 packet_put_cstring(authctxt->method->name); 919 packet_put_char(0); 920 packet_put_cstring(password); 921 memset(password, 0, strlen(password)); 922 xfree(password); 923 packet_add_padding(64); 924 packet_send(); 925 926 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 927 &input_userauth_passwd_changereq); 928 929 return 1; 930} 931 932/* 933 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 934 */ 935/* ARGSUSED */ 936void 937input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 938{ 939 Authctxt *authctxt = ctxt; 940 char *info, *lang, *password = NULL, *retype = NULL; 941 char prompt[150]; 942 const char *host = options.host_key_alias ? options.host_key_alias : 943 authctxt->host; 944 945 debug2("input_userauth_passwd_changereq"); 946 947 if (authctxt == NULL) 948 fatal("input_userauth_passwd_changereq: " 949 "no authentication context"); 950 951 info = packet_get_string(NULL); 952 lang = packet_get_string(NULL); 953 if (strlen(info) > 0) 954 logit("%s", info); 955 xfree(info); 956 xfree(lang); 957 packet_start(SSH2_MSG_USERAUTH_REQUEST); 958 packet_put_cstring(authctxt->server_user); 959 packet_put_cstring(authctxt->service); 960 packet_put_cstring(authctxt->method->name); 961 packet_put_char(1); /* additional info */ 962 snprintf(prompt, sizeof(prompt), 963 "Enter %.30s@%.128s's old password: ", 964 authctxt->server_user, host); 965 password = read_passphrase(prompt, 0); 966 packet_put_cstring(password); 967 memset(password, 0, strlen(password)); 968 xfree(password); 969 password = NULL; 970 while (password == NULL) { 971 snprintf(prompt, sizeof(prompt), 972 "Enter %.30s@%.128s's new password: ", 973 authctxt->server_user, host); 974 password = read_passphrase(prompt, RP_ALLOW_EOF); 975 if (password == NULL) { 976 /* bail out */ 977 return; 978 } 979 snprintf(prompt, sizeof(prompt), 980 "Retype %.30s@%.128s's new password: ", 981 authctxt->server_user, host); 982 retype = read_passphrase(prompt, 0); 983 if (strcmp(password, retype) != 0) { 984 memset(password, 0, strlen(password)); 985 xfree(password); 986 logit("Mismatch; try again, EOF to quit."); 987 password = NULL; 988 } 989 memset(retype, 0, strlen(retype)); 990 xfree(retype); 991 } 992 packet_put_cstring(password); 993 memset(password, 0, strlen(password)); 994 xfree(password); 995 packet_add_padding(64); 996 packet_send(); 997 998 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 999 &input_userauth_passwd_changereq); 1000} 1001 1002#ifdef JPAKE 1003static char * 1004pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 1005{ 1006 /* OpenBSD crypt(3) handles all of these */ 1007 if (strcmp(crypt_scheme, "crypt") == 0 || 1008 strcmp(crypt_scheme, "bcrypt") == 0 || 1009 strcmp(crypt_scheme, "md5crypt") == 0 || 1010 strcmp(crypt_scheme, "crypt-extended") == 0) 1011 return xstrdup(crypt(password, salt)); 1012 error("%s: unsupported password encryption scheme \"%.100s\"", 1013 __func__, crypt_scheme); 1014 return NULL; 1015} 1016 1017static BIGNUM * 1018jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 1019 const char *salt) 1020{ 1021 char prompt[256], *password, *crypted; 1022 u_char *secret; 1023 u_int secret_len; 1024 BIGNUM *ret; 1025 1026 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 1027 authctxt->server_user, authctxt->host); 1028 password = read_passphrase(prompt, 0); 1029 1030 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 1031 logit("Disabling %s authentication", authctxt->method->name); 1032 authctxt->method->enabled = NULL; 1033 /* Continue with an empty password to fail gracefully */ 1034 crypted = xstrdup(""); 1035 } 1036 1037#ifdef JPAKE_DEBUG 1038 debug3("%s: salt = %s", __func__, salt); 1039 debug3("%s: scheme = %s", __func__, crypt_scheme); 1040 debug3("%s: crypted = %s", __func__, crypted); 1041#endif 1042 1043 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 1044 &secret, &secret_len) != 0) 1045 fatal("%s: hash_buffer", __func__); 1046 1047 bzero(password, strlen(password)); 1048 bzero(crypted, strlen(crypted)); 1049 xfree(password); 1050 xfree(crypted); 1051 1052 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 1053 fatal("%s: BN_bin2bn (secret)", __func__); 1054 bzero(secret, secret_len); 1055 xfree(secret); 1056 1057 return ret; 1058} 1059 1060/* ARGSUSED */ 1061void 1062input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 1063{ 1064 Authctxt *authctxt = ctxt; 1065 struct jpake_ctx *pctx = authctxt->methoddata; 1066 u_char *x3_proof, *x4_proof, *x2_s_proof; 1067 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 1068 char *crypt_scheme, *salt; 1069 1070 /* Disable this message */ 1071 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 1072 1073 if ((pctx->g_x3 = BN_new()) == NULL || 1074 (pctx->g_x4 = BN_new()) == NULL) 1075 fatal("%s: BN_new", __func__); 1076 1077 /* Fetch step 1 values */ 1078 crypt_scheme = packet_get_string(NULL); 1079 salt = packet_get_string(NULL); 1080 pctx->server_id = packet_get_string(&pctx->server_id_len); 1081 packet_get_bignum2(pctx->g_x3); 1082 packet_get_bignum2(pctx->g_x4); 1083 x3_proof = packet_get_string(&x3_proof_len); 1084 x4_proof = packet_get_string(&x4_proof_len); 1085 packet_check_eom(); 1086 1087 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1088 1089 /* Obtain password and derive secret */ 1090 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1091 bzero(crypt_scheme, strlen(crypt_scheme)); 1092 bzero(salt, strlen(salt)); 1093 xfree(crypt_scheme); 1094 xfree(salt); 1095 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1096 1097 /* Calculate step 2 values */ 1098 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1099 pctx->g_x3, pctx->g_x4, pctx->x2, 1100 pctx->server_id, pctx->server_id_len, 1101 pctx->client_id, pctx->client_id_len, 1102 x3_proof, x3_proof_len, 1103 x4_proof, x4_proof_len, 1104 &pctx->a, 1105 &x2_s_proof, &x2_s_proof_len); 1106 1107 bzero(x3_proof, x3_proof_len); 1108 bzero(x4_proof, x4_proof_len); 1109 xfree(x3_proof); 1110 xfree(x4_proof); 1111 1112 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1113 1114 /* Send values for step 2 */ 1115 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1116 packet_put_bignum2(pctx->a); 1117 packet_put_string(x2_s_proof, x2_s_proof_len); 1118 packet_send(); 1119 1120 bzero(x2_s_proof, x2_s_proof_len); 1121 xfree(x2_s_proof); 1122 1123 /* Expect step 2 packet from peer */ 1124 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1125 input_userauth_jpake_server_step2); 1126} 1127 1128/* ARGSUSED */ 1129void 1130input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1131{ 1132 Authctxt *authctxt = ctxt; 1133 struct jpake_ctx *pctx = authctxt->methoddata; 1134 u_char *x4_s_proof; 1135 u_int x4_s_proof_len; 1136 1137 /* Disable this message */ 1138 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1139 1140 if ((pctx->b = BN_new()) == NULL) 1141 fatal("%s: BN_new", __func__); 1142 1143 /* Fetch step 2 values */ 1144 packet_get_bignum2(pctx->b); 1145 x4_s_proof = packet_get_string(&x4_s_proof_len); 1146 packet_check_eom(); 1147 1148 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1149 1150 /* Derive shared key and calculate confirmation hash */ 1151 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1152 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1153 pctx->client_id, pctx->client_id_len, 1154 pctx->server_id, pctx->server_id_len, 1155 session_id2, session_id2_len, 1156 x4_s_proof, x4_s_proof_len, 1157 &pctx->k, 1158 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1159 1160 bzero(x4_s_proof, x4_s_proof_len); 1161 xfree(x4_s_proof); 1162 1163 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1164 1165 /* Send key confirmation proof */ 1166 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1167 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1168 packet_send(); 1169 1170 /* Expect confirmation from peer */ 1171 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1172 input_userauth_jpake_server_confirm); 1173} 1174 1175/* ARGSUSED */ 1176void 1177input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1178{ 1179 Authctxt *authctxt = ctxt; 1180 struct jpake_ctx *pctx = authctxt->methoddata; 1181 1182 /* Disable this message */ 1183 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1184 1185 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1186 packet_check_eom(); 1187 1188 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1189 1190 /* Verify expected confirmation hash */ 1191 if (jpake_check_confirm(pctx->k, 1192 pctx->server_id, pctx->server_id_len, 1193 session_id2, session_id2_len, 1194 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1195 debug("%s: %s success", __func__, authctxt->method->name); 1196 else { 1197 debug("%s: confirmation mismatch", __func__); 1198 /* XXX stash this so if auth succeeds then we can warn/kill */ 1199 } 1200 1201 userauth_jpake_cleanup(authctxt); 1202} 1203#endif /* JPAKE */ 1204 1205static int 1206identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1207 u_char *data, u_int datalen) 1208{ 1209 Key *prv; 1210 int ret; 1211 1212 /* the agent supports this key */ 1213 if (id->ac) 1214 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1215 data, datalen)); 1216 /* 1217 * we have already loaded the private key or 1218 * the private key is stored in external hardware 1219 */ 1220 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1221 return (key_sign(id->key, sigp, lenp, data, datalen)); 1222 /* load the private key from the file */ 1223 if ((prv = load_identity_file(id->filename)) == NULL) 1224 return (-1); 1225 ret = key_sign(prv, sigp, lenp, data, datalen); 1226 key_free(prv); 1227 return (ret); 1228} 1229 1230static int 1231sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1232{ 1233 Buffer b; 1234 u_char *blob, *signature; 1235 u_int bloblen, slen; 1236 u_int skip = 0; 1237 int ret = -1; 1238 int have_sig = 1; 1239 char *fp; 1240 1241 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1242 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1243 xfree(fp); 1244 1245 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1246 /* we cannot handle this key */ 1247 debug3("sign_and_send_pubkey: cannot handle key"); 1248 return 0; 1249 } 1250 /* data to be signed */ 1251 buffer_init(&b); 1252 if (datafellows & SSH_OLD_SESSIONID) { 1253 buffer_append(&b, session_id2, session_id2_len); 1254 skip = session_id2_len; 1255 } else { 1256 buffer_put_string(&b, session_id2, session_id2_len); 1257 skip = buffer_len(&b); 1258 } 1259 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1260 buffer_put_cstring(&b, authctxt->server_user); 1261 buffer_put_cstring(&b, 1262 datafellows & SSH_BUG_PKSERVICE ? 1263 "ssh-userauth" : 1264 authctxt->service); 1265 if (datafellows & SSH_BUG_PKAUTH) { 1266 buffer_put_char(&b, have_sig); 1267 } else { 1268 buffer_put_cstring(&b, authctxt->method->name); 1269 buffer_put_char(&b, have_sig); 1270 buffer_put_cstring(&b, key_ssh_name(id->key)); 1271 } 1272 buffer_put_string(&b, blob, bloblen); 1273 1274 /* generate signature */ 1275 ret = identity_sign(id, &signature, &slen, 1276 buffer_ptr(&b), buffer_len(&b)); 1277 if (ret == -1) { 1278 xfree(blob); 1279 buffer_free(&b); 1280 return 0; 1281 } 1282#ifdef DEBUG_PK 1283 buffer_dump(&b); 1284#endif 1285 if (datafellows & SSH_BUG_PKSERVICE) { 1286 buffer_clear(&b); 1287 buffer_append(&b, session_id2, session_id2_len); 1288 skip = session_id2_len; 1289 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1290 buffer_put_cstring(&b, authctxt->server_user); 1291 buffer_put_cstring(&b, authctxt->service); 1292 buffer_put_cstring(&b, authctxt->method->name); 1293 buffer_put_char(&b, have_sig); 1294 if (!(datafellows & SSH_BUG_PKAUTH)) 1295 buffer_put_cstring(&b, key_ssh_name(id->key)); 1296 buffer_put_string(&b, blob, bloblen); 1297 } 1298 xfree(blob); 1299 1300 /* append signature */ 1301 buffer_put_string(&b, signature, slen); 1302 xfree(signature); 1303 1304 /* skip session id and packet type */ 1305 if (buffer_len(&b) < skip + 1) 1306 fatal("userauth_pubkey: internal error"); 1307 buffer_consume(&b, skip + 1); 1308 1309 /* put remaining data from buffer into packet */ 1310 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1311 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1312 buffer_free(&b); 1313 packet_send(); 1314 1315 return 1; 1316} 1317 1318static int 1319send_pubkey_test(Authctxt *authctxt, Identity *id) 1320{ 1321 u_char *blob; 1322 u_int bloblen, have_sig = 0; 1323 1324 debug3("send_pubkey_test"); 1325 1326 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1327 /* we cannot handle this key */ 1328 debug3("send_pubkey_test: cannot handle key"); 1329 return 0; 1330 } 1331 /* register callback for USERAUTH_PK_OK message */ 1332 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1333 1334 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1335 packet_put_cstring(authctxt->server_user); 1336 packet_put_cstring(authctxt->service); 1337 packet_put_cstring(authctxt->method->name); 1338 packet_put_char(have_sig); 1339 if (!(datafellows & SSH_BUG_PKAUTH)) 1340 packet_put_cstring(key_ssh_name(id->key)); 1341 packet_put_string(blob, bloblen); 1342 xfree(blob); 1343 packet_send(); 1344 return 1; 1345} 1346 1347static Key * 1348load_identity_file(char *filename) 1349{ 1350 Key *private; 1351 char prompt[300], *passphrase; 1352 int perm_ok = 0, quit, i; 1353 struct stat st; 1354 1355 if (stat(filename, &st) < 0) { 1356 debug3("no such identity: %s", filename); 1357 return NULL; 1358 } 1359 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1360 if (!perm_ok) 1361 return NULL; 1362 if (private == NULL) { 1363 if (options.batch_mode) 1364 return NULL; 1365 snprintf(prompt, sizeof prompt, 1366 "Enter passphrase for key '%.100s': ", filename); 1367 for (i = 0; i < options.number_of_password_prompts; i++) { 1368 passphrase = read_passphrase(prompt, 0); 1369 if (strcmp(passphrase, "") != 0) { 1370 private = key_load_private_type(KEY_UNSPEC, 1371 filename, passphrase, NULL, NULL); 1372 quit = 0; 1373 } else { 1374 debug2("no passphrase given, try next key"); 1375 quit = 1; 1376 } 1377 memset(passphrase, 0, strlen(passphrase)); 1378 xfree(passphrase); 1379 if (private != NULL || quit) 1380 break; 1381 debug2("bad passphrase given, try again..."); 1382 } 1383 } 1384 return private; 1385} 1386 1387/* 1388 * try keys in the following order: 1389 * 1. agent keys that are found in the config file 1390 * 2. other agent keys 1391 * 3. keys that are only listed in the config file 1392 */ 1393static void 1394pubkey_prepare(Authctxt *authctxt) 1395{ 1396 Identity *id; 1397 Idlist agent, files, *preferred; 1398 Key *key; 1399 AuthenticationConnection *ac; 1400 char *comment; 1401 int i, found; 1402 1403 TAILQ_INIT(&agent); /* keys from the agent */ 1404 TAILQ_INIT(&files); /* keys from the config file */ 1405 preferred = &authctxt->keys; 1406 TAILQ_INIT(preferred); /* preferred order of keys */ 1407 1408 /* list of keys stored in the filesystem */ 1409 for (i = 0; i < options.num_identity_files; i++) { 1410 key = options.identity_keys[i]; 1411 if (key && key->type == KEY_RSA1) 1412 continue; 1413 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1414 continue; 1415 options.identity_keys[i] = NULL; 1416 id = xcalloc(1, sizeof(*id)); 1417 id->key = key; 1418 id->filename = xstrdup(options.identity_files[i]); 1419 TAILQ_INSERT_TAIL(&files, id, next); 1420 } 1421 /* list of keys supported by the agent */ 1422 if ((ac = ssh_get_authentication_connection())) { 1423 for (key = ssh_get_first_identity(ac, &comment, 2); 1424 key != NULL; 1425 key = ssh_get_next_identity(ac, &comment, 2)) { 1426 found = 0; 1427 TAILQ_FOREACH(id, &files, next) { 1428 /* agent keys from the config file are preferred */ 1429 if (key_equal(key, id->key)) { 1430 key_free(key); 1431 xfree(comment); 1432 TAILQ_REMOVE(&files, id, next); 1433 TAILQ_INSERT_TAIL(preferred, id, next); 1434 id->ac = ac; 1435 found = 1; 1436 break; 1437 } 1438 } 1439 if (!found && !options.identities_only) { 1440 id = xcalloc(1, sizeof(*id)); 1441 id->key = key; 1442 id->filename = comment; 1443 id->ac = ac; 1444 TAILQ_INSERT_TAIL(&agent, id, next); 1445 } 1446 } 1447 /* append remaining agent keys */ 1448 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1449 TAILQ_REMOVE(&agent, id, next); 1450 TAILQ_INSERT_TAIL(preferred, id, next); 1451 } 1452 authctxt->agent = ac; 1453 } 1454 /* append remaining keys from the config file */ 1455 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1456 TAILQ_REMOVE(&files, id, next); 1457 TAILQ_INSERT_TAIL(preferred, id, next); 1458 } 1459 TAILQ_FOREACH(id, preferred, next) { 1460 debug2("key: %s (%p)", id->filename, id->key); 1461 } 1462} 1463 1464static void 1465pubkey_cleanup(Authctxt *authctxt) 1466{ 1467 Identity *id; 1468 1469 if (authctxt->agent != NULL) 1470 ssh_close_authentication_connection(authctxt->agent); 1471 for (id = TAILQ_FIRST(&authctxt->keys); id; 1472 id = TAILQ_FIRST(&authctxt->keys)) { 1473 TAILQ_REMOVE(&authctxt->keys, id, next); 1474 if (id->key) 1475 key_free(id->key); 1476 if (id->filename) 1477 xfree(id->filename); 1478 xfree(id); 1479 } 1480} 1481 1482int 1483userauth_pubkey(Authctxt *authctxt) 1484{ 1485 Identity *id; 1486 int sent = 0; 1487 1488 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1489 if (id->tried++) 1490 return (0); 1491 /* move key to the end of the queue */ 1492 TAILQ_REMOVE(&authctxt->keys, id, next); 1493 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1494 /* 1495 * send a test message if we have the public key. for 1496 * encrypted keys we cannot do this and have to load the 1497 * private key instead 1498 */ 1499 if (id->key && id->key->type != KEY_RSA1) { 1500 debug("Offering %s public key: %s", key_type(id->key), 1501 id->filename); 1502 sent = send_pubkey_test(authctxt, id); 1503 } else if (id->key == NULL) { 1504 debug("Trying private key: %s", id->filename); 1505 id->key = load_identity_file(id->filename); 1506 if (id->key != NULL) { 1507 id->isprivate = 1; 1508 sent = sign_and_send_pubkey(authctxt, id); 1509 key_free(id->key); 1510 id->key = NULL; 1511 } 1512 } 1513 if (sent) 1514 return (sent); 1515 } 1516 return (0); 1517} 1518 1519/* 1520 * Send userauth request message specifying keyboard-interactive method. 1521 */ 1522int 1523userauth_kbdint(Authctxt *authctxt) 1524{ 1525 static int attempt = 0; 1526 1527 if (attempt++ >= options.number_of_password_prompts) 1528 return 0; 1529 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1530 if (attempt > 1 && !authctxt->info_req_seen) { 1531 debug3("userauth_kbdint: disable: no info_req_seen"); 1532 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1533 return 0; 1534 } 1535 1536 debug2("userauth_kbdint"); 1537 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1538 packet_put_cstring(authctxt->server_user); 1539 packet_put_cstring(authctxt->service); 1540 packet_put_cstring(authctxt->method->name); 1541 packet_put_cstring(""); /* lang */ 1542 packet_put_cstring(options.kbd_interactive_devices ? 1543 options.kbd_interactive_devices : ""); 1544 packet_send(); 1545 1546 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1547 return 1; 1548} 1549 1550/* 1551 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1552 */ 1553void 1554input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1555{ 1556 Authctxt *authctxt = ctxt; 1557 char *name, *inst, *lang, *prompt, *response; 1558 u_int num_prompts, i; 1559 int echo = 0; 1560 1561 debug2("input_userauth_info_req"); 1562 1563 if (authctxt == NULL) 1564 fatal("input_userauth_info_req: no authentication context"); 1565 1566 authctxt->info_req_seen = 1; 1567 1568 name = packet_get_string(NULL); 1569 inst = packet_get_string(NULL); 1570 lang = packet_get_string(NULL); 1571 if (strlen(name) > 0) 1572 logit("%s", name); 1573 if (strlen(inst) > 0) 1574 logit("%s", inst); 1575 xfree(name); 1576 xfree(inst); 1577 xfree(lang); 1578 1579 num_prompts = packet_get_int(); 1580 /* 1581 * Begin to build info response packet based on prompts requested. 1582 * We commit to providing the correct number of responses, so if 1583 * further on we run into a problem that prevents this, we have to 1584 * be sure and clean this up and send a correct error response. 1585 */ 1586 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1587 packet_put_int(num_prompts); 1588 1589 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1590 for (i = 0; i < num_prompts; i++) { 1591 prompt = packet_get_string(NULL); 1592 echo = packet_get_char(); 1593 1594 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1595 1596 packet_put_cstring(response); 1597 memset(response, 0, strlen(response)); 1598 xfree(response); 1599 xfree(prompt); 1600 } 1601 packet_check_eom(); /* done with parsing incoming message. */ 1602 1603 packet_add_padding(64); 1604 packet_send(); 1605} 1606 1607static int 1608ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1609 u_char *data, u_int datalen) 1610{ 1611 Buffer b; 1612 struct stat st; 1613 pid_t pid; 1614 int to[2], from[2], status, version = 2; 1615 1616 debug2("ssh_keysign called"); 1617 1618 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1619 error("ssh_keysign: not installed: %s", strerror(errno)); 1620 return -1; 1621 } 1622 if (fflush(stdout) != 0) 1623 error("ssh_keysign: fflush: %s", strerror(errno)); 1624 if (pipe(to) < 0) { 1625 error("ssh_keysign: pipe: %s", strerror(errno)); 1626 return -1; 1627 } 1628 if (pipe(from) < 0) { 1629 error("ssh_keysign: pipe: %s", strerror(errno)); 1630 return -1; 1631 } 1632 if ((pid = fork()) < 0) { 1633 error("ssh_keysign: fork: %s", strerror(errno)); 1634 return -1; 1635 } 1636 if (pid == 0) { 1637 /* keep the socket on exec */ 1638 fcntl(packet_get_connection_in(), F_SETFD, 0); 1639 permanently_drop_suid(getuid()); 1640 close(from[0]); 1641 if (dup2(from[1], STDOUT_FILENO) < 0) 1642 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1643 close(to[1]); 1644 if (dup2(to[0], STDIN_FILENO) < 0) 1645 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1646 close(from[1]); 1647 close(to[0]); 1648 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1649 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1650 strerror(errno)); 1651 } 1652 close(from[1]); 1653 close(to[0]); 1654 1655 buffer_init(&b); 1656 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1657 buffer_put_string(&b, data, datalen); 1658 if (ssh_msg_send(to[1], version, &b) == -1) 1659 fatal("ssh_keysign: couldn't send request"); 1660 1661 if (ssh_msg_recv(from[0], &b) < 0) { 1662 error("ssh_keysign: no reply"); 1663 buffer_free(&b); 1664 return -1; 1665 } 1666 close(from[0]); 1667 close(to[1]); 1668 1669 while (waitpid(pid, &status, 0) < 0) 1670 if (errno != EINTR) 1671 break; 1672 1673 if (buffer_get_char(&b) != version) { 1674 error("ssh_keysign: bad version"); 1675 buffer_free(&b); 1676 return -1; 1677 } 1678 *sigp = buffer_get_string(&b, lenp); 1679 buffer_free(&b); 1680 1681 return 0; 1682} 1683 1684int 1685userauth_hostbased(Authctxt *authctxt) 1686{ 1687 Key *private = NULL; 1688 Sensitive *sensitive = authctxt->sensitive; 1689 Buffer b; 1690 u_char *signature, *blob; 1691 char *chost, *pkalg, *p; 1692 const char *service; 1693 u_int blen, slen; 1694 int ok, i, found = 0; 1695 1696 /* check for a useful key */ 1697 for (i = 0; i < sensitive->nkeys; i++) { 1698 private = sensitive->keys[i]; 1699 if (private && private->type != KEY_RSA1) { 1700 found = 1; 1701 /* we take and free the key */ 1702 sensitive->keys[i] = NULL; 1703 break; 1704 } 1705 } 1706 if (!found) { 1707 debug("No more client hostkeys for hostbased authentication."); 1708 return 0; 1709 } 1710 if (key_to_blob(private, &blob, &blen) == 0) { 1711 key_free(private); 1712 return 0; 1713 } 1714 /* figure out a name for the client host */ 1715 p = get_local_name(packet_get_connection_in()); 1716 if (p == NULL) { 1717 error("userauth_hostbased: cannot get local ipaddr/name"); 1718 key_free(private); 1719 xfree(blob); 1720 return 0; 1721 } 1722 xasprintf(&chost, "%s.", p); 1723 debug2("userauth_hostbased: chost %s", chost); 1724 xfree(p); 1725 1726 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1727 authctxt->service; 1728 pkalg = xstrdup(key_ssh_name(private)); 1729 buffer_init(&b); 1730 /* construct data */ 1731 buffer_put_string(&b, session_id2, session_id2_len); 1732 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1733 buffer_put_cstring(&b, authctxt->server_user); 1734 buffer_put_cstring(&b, service); 1735 buffer_put_cstring(&b, authctxt->method->name); 1736 buffer_put_cstring(&b, pkalg); 1737 buffer_put_string(&b, blob, blen); 1738 buffer_put_cstring(&b, chost); 1739 buffer_put_cstring(&b, authctxt->local_user); 1740#ifdef DEBUG_PK 1741 buffer_dump(&b); 1742#endif 1743 if (sensitive->external_keysign) 1744 ok = ssh_keysign(private, &signature, &slen, 1745 buffer_ptr(&b), buffer_len(&b)); 1746 else 1747 ok = key_sign(private, &signature, &slen, 1748 buffer_ptr(&b), buffer_len(&b)); 1749 key_free(private); 1750 buffer_free(&b); 1751 if (ok != 0) { 1752 error("key_sign failed"); 1753 xfree(chost); 1754 xfree(pkalg); 1755 xfree(blob); 1756 return 0; 1757 } 1758 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1759 packet_put_cstring(authctxt->server_user); 1760 packet_put_cstring(authctxt->service); 1761 packet_put_cstring(authctxt->method->name); 1762 packet_put_cstring(pkalg); 1763 packet_put_string(blob, blen); 1764 packet_put_cstring(chost); 1765 packet_put_cstring(authctxt->local_user); 1766 packet_put_string(signature, slen); 1767 memset(signature, 's', slen); 1768 xfree(signature); 1769 xfree(chost); 1770 xfree(pkalg); 1771 xfree(blob); 1772 1773 packet_send(); 1774 return 1; 1775} 1776 1777#ifdef JPAKE 1778int 1779userauth_jpake(Authctxt *authctxt) 1780{ 1781 struct jpake_ctx *pctx; 1782 u_char *x1_proof, *x2_proof; 1783 u_int x1_proof_len, x2_proof_len; 1784 static int attempt = 0; /* XXX share with userauth_password's? */ 1785 1786 if (attempt++ >= options.number_of_password_prompts) 1787 return 0; 1788 if (attempt != 1) 1789 error("Permission denied, please try again."); 1790 1791 if (authctxt->methoddata != NULL) 1792 fatal("%s: authctxt->methoddata already set (%p)", 1793 __func__, authctxt->methoddata); 1794 1795 authctxt->methoddata = pctx = jpake_new(); 1796 1797 /* 1798 * Send request immediately, to get the protocol going while 1799 * we do the initial computations. 1800 */ 1801 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1802 packet_put_cstring(authctxt->server_user); 1803 packet_put_cstring(authctxt->service); 1804 packet_put_cstring(authctxt->method->name); 1805 packet_send(); 1806 packet_write_wait(); 1807 1808 jpake_step1(pctx->grp, 1809 &pctx->client_id, &pctx->client_id_len, 1810 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1811 &x1_proof, &x1_proof_len, 1812 &x2_proof, &x2_proof_len); 1813 1814 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1815 1816 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1817 packet_put_string(pctx->client_id, pctx->client_id_len); 1818 packet_put_bignum2(pctx->g_x1); 1819 packet_put_bignum2(pctx->g_x2); 1820 packet_put_string(x1_proof, x1_proof_len); 1821 packet_put_string(x2_proof, x2_proof_len); 1822 packet_send(); 1823 1824 bzero(x1_proof, x1_proof_len); 1825 bzero(x2_proof, x2_proof_len); 1826 xfree(x1_proof); 1827 xfree(x2_proof); 1828 1829 /* Expect step 1 packet from peer */ 1830 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1831 input_userauth_jpake_server_step1); 1832 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1833 &input_userauth_success_unexpected); 1834 1835 return 1; 1836} 1837 1838void 1839userauth_jpake_cleanup(Authctxt *authctxt) 1840{ 1841 debug3("%s: clean up", __func__); 1842 if (authctxt->methoddata != NULL) { 1843 jpake_free(authctxt->methoddata); 1844 authctxt->methoddata = NULL; 1845 } 1846 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1847} 1848#endif /* JPAKE */ 1849 1850/* find auth method */ 1851 1852/* 1853 * given auth method name, if configurable options permit this method fill 1854 * in auth_ident field and return true, otherwise return false. 1855 */ 1856static int 1857authmethod_is_enabled(Authmethod *method) 1858{ 1859 if (method == NULL) 1860 return 0; 1861 /* return false if options indicate this method is disabled */ 1862 if (method->enabled == NULL || *method->enabled == 0) 1863 return 0; 1864 /* return false if batch mode is enabled but method needs interactive mode */ 1865 if (method->batch_flag != NULL && *method->batch_flag != 0) 1866 return 0; 1867 return 1; 1868} 1869 1870static Authmethod * 1871authmethod_lookup(const char *name) 1872{ 1873 Authmethod *method = NULL; 1874 if (name != NULL) 1875 for (method = authmethods; method->name != NULL; method++) 1876 if (strcmp(name, method->name) == 0) 1877 return method; 1878 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1879 return NULL; 1880} 1881 1882/* XXX internal state */ 1883static Authmethod *current = NULL; 1884static char *supported = NULL; 1885static char *preferred = NULL; 1886 1887/* 1888 * Given the authentication method list sent by the server, return the 1889 * next method we should try. If the server initially sends a nil list, 1890 * use a built-in default list. 1891 */ 1892static Authmethod * 1893authmethod_get(char *authlist) 1894{ 1895 char *name = NULL; 1896 u_int next; 1897 1898 /* Use a suitable default if we're passed a nil list. */ 1899 if (authlist == NULL || strlen(authlist) == 0) 1900 authlist = options.preferred_authentications; 1901 1902 if (supported == NULL || strcmp(authlist, supported) != 0) { 1903 debug3("start over, passed a different list %s", authlist); 1904 if (supported != NULL) 1905 xfree(supported); 1906 supported = xstrdup(authlist); 1907 preferred = options.preferred_authentications; 1908 debug3("preferred %s", preferred); 1909 current = NULL; 1910 } else if (current != NULL && authmethod_is_enabled(current)) 1911 return current; 1912 1913 for (;;) { 1914 if ((name = match_list(preferred, supported, &next)) == NULL) { 1915 debug("No more authentication methods to try."); 1916 current = NULL; 1917 return NULL; 1918 } 1919 preferred += next; 1920 debug3("authmethod_lookup %s", name); 1921 debug3("remaining preferred: %s", preferred); 1922 if ((current = authmethod_lookup(name)) != NULL && 1923 authmethod_is_enabled(current)) { 1924 debug3("authmethod_is_enabled %s", name); 1925 debug("Next authentication method: %s", name); 1926 xfree(name); 1927 return current; 1928 } 1929 } 1930 if (name != NULL) 1931 xfree(name); 1932} 1933 1934static char * 1935authmethods_get(void) 1936{ 1937 Authmethod *method = NULL; 1938 Buffer b; 1939 char *list; 1940 1941 buffer_init(&b); 1942 for (method = authmethods; method->name != NULL; method++) { 1943 if (authmethod_is_enabled(method)) { 1944 if (buffer_len(&b) > 0) 1945 buffer_append(&b, ",", 1); 1946 buffer_append(&b, method->name, strlen(method->name)); 1947 } 1948 } 1949 buffer_append(&b, "\0", 1); 1950 list = xstrdup(buffer_ptr(&b)); 1951 buffer_free(&b); 1952 return list; 1953} 1954 1955