1/* $OpenBSD: sshconnect2.c,v 1.192 2013/02/17 23:16:57 dtucker Exp $ */ 2/* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include "includes.h" 28 29#include <sys/types.h> 30#include <sys/socket.h> 31#include <sys/wait.h> 32#include <sys/stat.h> 33 34#include <errno.h> 35#include <fcntl.h> 36#include <netdb.h> 37#include <pwd.h> 38#include <signal.h> 39#include <stdarg.h> 40#include <stdio.h> 41#include <string.h> 42#include <unistd.h> 43#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS) 44#include <vis.h> 45#endif 46 47#include "openbsd-compat/sys-queue.h" 48 49#include "xmalloc.h" 50#include "ssh.h" 51#include "ssh2.h" 52#include "buffer.h" 53#include "packet.h" 54#include "compat.h" 55#include "cipher.h" 56#include "key.h" 57#include "kex.h" 58#include "myproposal.h" 59#include "sshconnect.h" 60#include "authfile.h" 61#include "dh.h" 62#include "authfd.h" 63#include "log.h" 64#include "readconf.h" 65#include "misc.h" 66#include "match.h" 67#include "dispatch.h" 68#include "canohost.h" 69#include "msg.h" 70#include "pathnames.h" 71#include "uidswap.h" 72#include "hostfile.h" 73#ifdef JPAKE 74#include "schnorr.h" 75#include "jpake.h" 76#endif 77#include "keychain.h" 78 79#ifdef GSSAPI 80#include "ssh-gss.h" 81#endif 82 83/* import */ 84extern char *client_version_string; 85extern char *server_version_string; 86extern Options options; 87 88/* 89 * SSH2 key exchange 90 */ 91 92u_char *session_id2 = NULL; 93u_int session_id2_len = 0; 94 95char *xxx_host; 96struct sockaddr *xxx_hostaddr; 97 98Kex *xxx_kex = NULL; 99 100static int 101verify_host_key_callback(Key *hostkey) 102{ 103 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 104 fatal("Host key verification failed."); 105 return 0; 106} 107 108static char * 109order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 110{ 111 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 112 size_t maxlen; 113 struct hostkeys *hostkeys; 114 int ktype; 115 u_int i; 116 117 /* Find all hostkeys for this hostname */ 118 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 119 hostkeys = init_hostkeys(); 120 for (i = 0; i < options.num_user_hostfiles; i++) 121 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 122 for (i = 0; i < options.num_system_hostfiles; i++) 123 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 124 125 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 126 maxlen = strlen(avail) + 1; 127 first = xmalloc(maxlen); 128 last = xmalloc(maxlen); 129 *first = *last = '\0'; 130 131#define ALG_APPEND(to, from) \ 132 do { \ 133 if (*to != '\0') \ 134 strlcat(to, ",", maxlen); \ 135 strlcat(to, from, maxlen); \ 136 } while (0) 137 138 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 139 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) 140 fatal("%s: unknown alg %s", __func__, alg); 141 if (lookup_key_in_hostkeys_by_type(hostkeys, 142 key_type_plain(ktype), NULL)) 143 ALG_APPEND(first, alg); 144 else 145 ALG_APPEND(last, alg); 146 } 147#undef ALG_APPEND 148 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); 149 if (*first != '\0') 150 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 151 152 xfree(first); 153 xfree(last); 154 xfree(hostname); 155 xfree(oavail); 156 free_hostkeys(hostkeys); 157 158 return ret; 159} 160 161void 162ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 163{ 164 Kex *kex; 165 166#ifdef GSSAPI 167 char *orig = NULL, *gss = NULL; 168 char *gss_host = NULL; 169#endif 170 171 xxx_host = host; 172 xxx_hostaddr = hostaddr; 173 174#ifdef GSSAPI 175 if (options.gss_keyex) { 176 /* Add the GSSAPI mechanisms currently supported on this 177 * client to the key exchange algorithm proposal */ 178 orig = myproposal[PROPOSAL_KEX_ALGS]; 179 180 if (options.gss_trust_dns) 181 gss_host = (char *)get_canonical_hostname(1); 182 else 183 gss_host = host; 184 185 gss = ssh_gssapi_client_mechanisms(gss_host, options.gss_client_identity); 186 if (gss) { 187 debug("Offering GSSAPI proposal: %s", gss); 188 xasprintf(&myproposal[PROPOSAL_KEX_ALGS], 189 "%s,%s", gss, orig); 190 } 191 } 192#endif 193 194 if (options.ciphers == (char *)-1) { 195 logit("No valid ciphers for protocol version 2 given, using defaults."); 196 options.ciphers = NULL; 197 } 198 if (options.ciphers != NULL) { 199 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 200 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 201 } 202 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 203 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 204 myproposal[PROPOSAL_ENC_ALGS_STOC] = 205 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 206 if (options.compression) { 207 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 208 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 209 } else { 210 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 211 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 212 } 213 if (options.macs != NULL) { 214 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 215 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 216 } 217 if (options.hostkeyalgorithms != NULL) 218 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 219 options.hostkeyalgorithms; 220 else { 221 /* Prefer algorithms that we already have keys for */ 222 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 223 order_hostkeyalgs(host, hostaddr, port); 224 } 225 if (options.kex_algorithms != NULL) 226 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 227 228#ifdef GSSAPI 229 /* If we've got GSSAPI algorithms, then we also support the 230 * 'null' hostkey, as a last resort */ 231 if (options.gss_keyex && gss) { 232 orig = myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS]; 233 xasprintf(&myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS], 234 "%s,null", orig); 235 xfree(gss); 236 } 237#endif 238 239 if (options.rekey_limit) 240 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 241 242 /* start key exchange */ 243 kex = kex_setup(myproposal); 244 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 245 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 246 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 247 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 248 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 249#ifdef GSSAPI 250 if (options.gss_keyex) { 251 kex->kex[KEX_GSS_GRP1_SHA1] = kexgss_client; 252 kex->kex[KEX_GSS_GRP14_SHA1] = kexgss_client; 253 kex->kex[KEX_GSS_GEX_SHA1] = kexgss_client; 254 } 255#endif 256 kex->client_version_string=client_version_string; 257 kex->server_version_string=server_version_string; 258 kex->verify_host_key=&verify_host_key_callback; 259 260#ifdef GSSAPI 261 if (options.gss_keyex) { 262 kex->gss_deleg_creds = options.gss_deleg_creds; 263 kex->gss_trust_dns = options.gss_trust_dns; 264 kex->gss_client = options.gss_client_identity; 265 if (options.gss_server_identity) { 266 kex->gss_host = options.gss_server_identity; 267 } else { 268 kex->gss_host = gss_host; 269 } 270 } 271#endif 272 273 xxx_kex = kex; 274 275 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 276 277 if (options.use_roaming && !kex->roaming) { 278 debug("Roaming not allowed by server"); 279 options.use_roaming = 0; 280 } 281 282 session_id2 = kex->session_id; 283 session_id2_len = kex->session_id_len; 284 285#ifdef DEBUG_KEXDH 286 /* send 1st encrypted/maced/compressed message */ 287 packet_start(SSH2_MSG_IGNORE); 288 packet_put_cstring("markus"); 289 packet_send(); 290 packet_write_wait(); 291#endif 292} 293 294/* 295 * Authenticate user 296 */ 297 298typedef struct Authctxt Authctxt; 299typedef struct Authmethod Authmethod; 300typedef struct identity Identity; 301typedef struct idlist Idlist; 302 303struct identity { 304 TAILQ_ENTRY(identity) next; 305 AuthenticationConnection *ac; /* set if agent supports key */ 306 Key *key; /* public/private key */ 307 char *filename; /* comment for agent-only keys */ 308 int tried; 309 int isprivate; /* key points to the private key */ 310 int userprovided; 311}; 312TAILQ_HEAD(idlist, identity); 313 314struct Authctxt { 315 const char *server_user; 316 const char *local_user; 317 const char *host; 318 const char *service; 319 Authmethod *method; 320 sig_atomic_t success; 321 char *authlist; 322 /* pubkey */ 323 Idlist keys; 324 AuthenticationConnection *agent; 325 /* hostbased */ 326 Sensitive *sensitive; 327 /* kbd-interactive */ 328 int info_req_seen; 329 /* generic */ 330 void *methoddata; 331}; 332struct Authmethod { 333 char *name; /* string to compare against server's list */ 334 int (*userauth)(Authctxt *authctxt); 335 void (*cleanup)(Authctxt *authctxt); 336 int *enabled; /* flag in option struct that enables method */ 337 int *batch_flag; /* flag in option struct that disables method */ 338}; 339 340void input_userauth_success(int, u_int32_t, void *); 341void input_userauth_success_unexpected(int, u_int32_t, void *); 342void input_userauth_failure(int, u_int32_t, void *); 343void input_userauth_banner(int, u_int32_t, void *); 344void input_userauth_error(int, u_int32_t, void *); 345void input_userauth_info_req(int, u_int32_t, void *); 346void input_userauth_pk_ok(int, u_int32_t, void *); 347void input_userauth_passwd_changereq(int, u_int32_t, void *); 348void input_userauth_jpake_server_step1(int, u_int32_t, void *); 349void input_userauth_jpake_server_step2(int, u_int32_t, void *); 350void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 351 352int userauth_none(Authctxt *); 353int userauth_pubkey(Authctxt *); 354int userauth_passwd(Authctxt *); 355int userauth_kbdint(Authctxt *); 356int userauth_hostbased(Authctxt *); 357int userauth_jpake(Authctxt *); 358 359void userauth_jpake_cleanup(Authctxt *); 360 361#ifdef GSSAPI 362int userauth_gssapi(Authctxt *authctxt); 363void input_gssapi_response(int type, u_int32_t, void *); 364void input_gssapi_token(int type, u_int32_t, void *); 365void input_gssapi_hash(int type, u_int32_t, void *); 366void input_gssapi_error(int, u_int32_t, void *); 367void input_gssapi_errtok(int, u_int32_t, void *); 368int userauth_gsskeyex(Authctxt *authctxt); 369#endif 370 371void userauth(Authctxt *, char *); 372 373static int sign_and_send_pubkey(Authctxt *, Identity *); 374static void pubkey_prepare(Authctxt *); 375static void pubkey_cleanup(Authctxt *); 376static Key *load_identity_file(char *, int); 377 378static Authmethod *authmethod_get(char *authlist); 379static Authmethod *authmethod_lookup(const char *name); 380static char *authmethods_get(void); 381 382Authmethod authmethods[] = { 383#ifdef GSSAPI 384 {"gssapi-keyex", 385 userauth_gsskeyex, 386 NULL, 387 &options.gss_authentication, 388 NULL}, 389 {"gssapi-with-mic", 390 userauth_gssapi, 391 NULL, 392 &options.gss_authentication, 393 NULL}, 394#endif 395 {"hostbased", 396 userauth_hostbased, 397 NULL, 398 &options.hostbased_authentication, 399 NULL}, 400 {"publickey", 401 userauth_pubkey, 402 NULL, 403 &options.pubkey_authentication, 404 NULL}, 405#ifdef JPAKE 406 {"jpake-01@openssh.com", 407 userauth_jpake, 408 userauth_jpake_cleanup, 409 &options.zero_knowledge_password_authentication, 410 &options.batch_mode}, 411#endif 412 {"keyboard-interactive", 413 userauth_kbdint, 414 NULL, 415 &options.kbd_interactive_authentication, 416 &options.batch_mode}, 417 {"password", 418 userauth_passwd, 419 NULL, 420 &options.password_authentication, 421 &options.batch_mode}, 422 {"none", 423 userauth_none, 424 NULL, 425 NULL, 426 NULL}, 427 {NULL, NULL, NULL, NULL, NULL} 428}; 429 430void 431ssh_userauth2(const char *local_user, const char *server_user, char *host, 432 Sensitive *sensitive) 433{ 434 Authctxt authctxt; 435 int type; 436 437 if (options.challenge_response_authentication) 438 options.kbd_interactive_authentication = 1; 439 440 packet_start(SSH2_MSG_SERVICE_REQUEST); 441 packet_put_cstring("ssh-userauth"); 442 packet_send(); 443 debug("SSH2_MSG_SERVICE_REQUEST sent"); 444 packet_write_wait(); 445 type = packet_read(); 446 if (type != SSH2_MSG_SERVICE_ACCEPT) 447 fatal("Server denied authentication request: %d", type); 448 if (packet_remaining() > 0) { 449 char *reply = packet_get_string(NULL); 450 debug2("service_accept: %s", reply); 451 xfree(reply); 452 } else { 453 debug2("buggy server: service_accept w/o service"); 454 } 455 packet_check_eom(); 456 debug("SSH2_MSG_SERVICE_ACCEPT received"); 457 458 if (options.preferred_authentications == NULL) 459 options.preferred_authentications = authmethods_get(); 460 461 /* setup authentication context */ 462 memset(&authctxt, 0, sizeof(authctxt)); 463 pubkey_prepare(&authctxt); 464 authctxt.server_user = server_user; 465 authctxt.local_user = local_user; 466 authctxt.host = host; 467 authctxt.service = "ssh-connection"; /* service name */ 468 authctxt.success = 0; 469 authctxt.method = authmethod_lookup("none"); 470 authctxt.authlist = NULL; 471 authctxt.methoddata = NULL; 472 authctxt.sensitive = sensitive; 473 authctxt.info_req_seen = 0; 474 if (authctxt.method == NULL) 475 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 476 477 /* initial userauth request */ 478 userauth_none(&authctxt); 479 480 dispatch_init(&input_userauth_error); 481 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 482 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 483 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 484 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 485 486 pubkey_cleanup(&authctxt); 487 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 488 489 debug("Authentication succeeded (%s).", authctxt.method->name); 490} 491 492void 493userauth(Authctxt *authctxt, char *authlist) 494{ 495 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 496 authctxt->method->cleanup(authctxt); 497 498 if (authctxt->methoddata) { 499 xfree(authctxt->methoddata); 500 authctxt->methoddata = NULL; 501 } 502 if (authlist == NULL) { 503 authlist = authctxt->authlist; 504 } else { 505 if (authctxt->authlist) 506 xfree(authctxt->authlist); 507 authctxt->authlist = authlist; 508 } 509 for (;;) { 510 Authmethod *method = authmethod_get(authlist); 511 if (method == NULL) 512 fatal("Permission denied (%s).", authlist); 513 authctxt->method = method; 514 515 /* reset the per method handler */ 516 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 517 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 518 519 /* and try new method */ 520 if (method->userauth(authctxt) != 0) { 521 debug2("we sent a %s packet, wait for reply", method->name); 522 break; 523 } else { 524 debug2("we did not send a packet, disable method"); 525 method->enabled = NULL; 526 } 527 } 528} 529 530/* ARGSUSED */ 531void 532input_userauth_error(int type, u_int32_t seq, void *ctxt) 533{ 534 fatal("input_userauth_error: bad message during authentication: " 535 "type %d", type); 536} 537 538/* ARGSUSED */ 539void 540input_userauth_banner(int type, u_int32_t seq, void *ctxt) 541{ 542 char *msg, *raw, *lang; 543 u_int len; 544 545 debug3("input_userauth_banner"); 546 raw = packet_get_string(&len); 547 lang = packet_get_string(NULL); 548 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 549 if (len > 65536) 550 len = 65536; 551 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 552 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 553 fprintf(stderr, "%s", msg); 554 xfree(msg); 555 } 556 xfree(raw); 557 xfree(lang); 558} 559 560/* ARGSUSED */ 561void 562input_userauth_success(int type, u_int32_t seq, void *ctxt) 563{ 564 Authctxt *authctxt = ctxt; 565 566 if (authctxt == NULL) 567 fatal("input_userauth_success: no authentication context"); 568 if (authctxt->authlist) { 569 xfree(authctxt->authlist); 570 authctxt->authlist = NULL; 571 } 572 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 573 authctxt->method->cleanup(authctxt); 574 if (authctxt->methoddata) { 575 xfree(authctxt->methoddata); 576 authctxt->methoddata = NULL; 577 } 578 authctxt->success = 1; /* break out */ 579} 580 581void 582input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 583{ 584 Authctxt *authctxt = ctxt; 585 586 if (authctxt == NULL) 587 fatal("%s: no authentication context", __func__); 588 589 fatal("Unexpected authentication success during %s.", 590 authctxt->method->name); 591} 592 593/* ARGSUSED */ 594void 595input_userauth_failure(int type, u_int32_t seq, void *ctxt) 596{ 597 Authctxt *authctxt = ctxt; 598 char *authlist = NULL; 599 int partial; 600 601 if (authctxt == NULL) 602 fatal("input_userauth_failure: no authentication context"); 603 604 authlist = packet_get_string(NULL); 605 partial = packet_get_char(); 606 packet_check_eom(); 607 608 if (partial != 0) 609 logit("Authenticated with partial success."); 610 debug("Authentications that can continue: %s", authlist); 611 612 userauth(authctxt, authlist); 613} 614 615/* ARGSUSED */ 616void 617input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 618{ 619 Authctxt *authctxt = ctxt; 620 Key *key = NULL; 621 Identity *id = NULL; 622 Buffer b; 623 int pktype, sent = 0; 624 u_int alen, blen; 625 char *pkalg, *fp; 626 u_char *pkblob; 627 628 if (authctxt == NULL) 629 fatal("input_userauth_pk_ok: no authentication context"); 630 if (datafellows & SSH_BUG_PKOK) { 631 /* this is similar to SSH_BUG_PKAUTH */ 632 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 633 pkblob = packet_get_string(&blen); 634 buffer_init(&b); 635 buffer_append(&b, pkblob, blen); 636 pkalg = buffer_get_string(&b, &alen); 637 buffer_free(&b); 638 } else { 639 pkalg = packet_get_string(&alen); 640 pkblob = packet_get_string(&blen); 641 } 642 packet_check_eom(); 643 644 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 645 646 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 647 debug("unknown pkalg %s", pkalg); 648 goto done; 649 } 650 if ((key = key_from_blob(pkblob, blen)) == NULL) { 651 debug("no key from blob. pkalg %s", pkalg); 652 goto done; 653 } 654 if (key->type != pktype) { 655 error("input_userauth_pk_ok: type mismatch " 656 "for decoded key (received %d, expected %d)", 657 key->type, pktype); 658 goto done; 659 } 660 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 661 debug2("input_userauth_pk_ok: fp %s", fp); 662 xfree(fp); 663 664 /* 665 * search keys in the reverse order, because last candidate has been 666 * moved to the end of the queue. this also avoids confusion by 667 * duplicate keys 668 */ 669 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 670 if (key_equal(key, id->key)) { 671 sent = sign_and_send_pubkey(authctxt, id); 672 break; 673 } 674 } 675done: 676 if (key != NULL) 677 key_free(key); 678 xfree(pkalg); 679 xfree(pkblob); 680 681 /* try another method if we did not send a packet */ 682 if (sent == 0) 683 userauth(authctxt, NULL); 684} 685 686#ifdef GSSAPI 687int 688userauth_gssapi(Authctxt *authctxt) 689{ 690 Gssctxt *gssctxt = NULL; 691 static gss_OID_set gss_supported = NULL; 692 static u_int mech = 0; 693 OM_uint32 min; 694 int ok = 0; 695 const char *gss_host; 696 697 if (options.gss_server_identity) 698 gss_host = options.gss_server_identity; 699 else if (options.gss_trust_dns) 700 gss_host = get_canonical_hostname(1); 701 else 702 gss_host = authctxt->host; 703 704 /* Try one GSSAPI method at a time, rather than sending them all at 705 * once. */ 706 707 if (gss_supported == NULL) 708 if (GSS_ERROR(gss_indicate_mechs(&min, &gss_supported))) { 709 gss_supported = NULL; 710 return 0; 711 } 712 713 /* Check to see if the mechanism is usable before we offer it */ 714 while (mech < gss_supported->count && !ok) { 715 /* My DER encoding requires length<128 */ 716 if (gss_supported->elements[mech].length < 128 && 717 ssh_gssapi_check_mechanism(&gssctxt, 718 &gss_supported->elements[mech], gss_host, 719 options.gss_client_identity)) { 720 ok = 1; /* Mechanism works */ 721 } else { 722 mech++; 723 } 724 } 725 726 if (!ok) 727 return 0; 728 729 authctxt->methoddata=(void *)gssctxt; 730 731 packet_start(SSH2_MSG_USERAUTH_REQUEST); 732 packet_put_cstring(authctxt->server_user); 733 packet_put_cstring(authctxt->service); 734 packet_put_cstring(authctxt->method->name); 735 736 packet_put_int(1); 737 738 packet_put_int((gss_supported->elements[mech].length) + 2); 739 packet_put_char(SSH_GSS_OIDTYPE); 740 packet_put_char(gss_supported->elements[mech].length); 741 packet_put_raw(gss_supported->elements[mech].elements, 742 gss_supported->elements[mech].length); 743 744 packet_send(); 745 746 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 747 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 748 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 749 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 750 751 mech++; /* Move along to next candidate */ 752 753 return 1; 754} 755 756static OM_uint32 757process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 758{ 759 Authctxt *authctxt = ctxt; 760 Gssctxt *gssctxt = authctxt->methoddata; 761 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 762 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 763 gss_buffer_desc gssbuf; 764 OM_uint32 status, ms, flags; 765 Buffer b; 766 767 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 768 recv_tok, &send_tok, &flags); 769 770 if (send_tok.length > 0) { 771 if (GSS_ERROR(status)) 772 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 773 else 774 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 775 776 packet_put_string(send_tok.value, send_tok.length); 777 packet_send(); 778 gss_release_buffer(&ms, &send_tok); 779 } 780 781 if (status == GSS_S_COMPLETE) { 782 /* send either complete or MIC, depending on mechanism */ 783 if (!(flags & GSS_C_INTEG_FLAG)) { 784 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 785 packet_send(); 786 } else { 787 ssh_gssapi_buildmic(&b, authctxt->server_user, 788 authctxt->service, "gssapi-with-mic"); 789 790 gssbuf.value = buffer_ptr(&b); 791 gssbuf.length = buffer_len(&b); 792 793 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 794 795 if (!GSS_ERROR(status)) { 796 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 797 packet_put_string(mic.value, mic.length); 798 799 packet_send(); 800 } 801 802 buffer_free(&b); 803 gss_release_buffer(&ms, &mic); 804 } 805 } 806 807 return status; 808} 809 810/* ARGSUSED */ 811void 812input_gssapi_response(int type, u_int32_t plen, void *ctxt) 813{ 814 Authctxt *authctxt = ctxt; 815 Gssctxt *gssctxt; 816 u_int oidlen; 817 u_char *oidv; 818 819 if (authctxt == NULL) 820 fatal("input_gssapi_response: no authentication context"); 821 gssctxt = authctxt->methoddata; 822 823 /* Setup our OID */ 824 oidv = packet_get_string(&oidlen); 825 826 if (oidlen <= 2 || 827 oidv[0] != SSH_GSS_OIDTYPE || 828 oidv[1] != oidlen - 2) { 829 xfree(oidv); 830 debug("Badly encoded mechanism OID received"); 831 userauth(authctxt, NULL); 832 return; 833 } 834 835 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 836 fatal("Server returned different OID than expected"); 837 838 packet_check_eom(); 839 840 xfree(oidv); 841 842 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 843 /* Start again with next method on list */ 844 debug("Trying to start again"); 845 userauth(authctxt, NULL); 846 return; 847 } 848} 849 850/* ARGSUSED */ 851void 852input_gssapi_token(int type, u_int32_t plen, void *ctxt) 853{ 854 Authctxt *authctxt = ctxt; 855 gss_buffer_desc recv_tok; 856 OM_uint32 status; 857 u_int slen; 858 859 if (authctxt == NULL) 860 fatal("input_gssapi_response: no authentication context"); 861 862 recv_tok.value = packet_get_string(&slen); 863 recv_tok.length = slen; /* safe typecast */ 864 865 packet_check_eom(); 866 867 status = process_gssapi_token(ctxt, &recv_tok); 868 869 xfree(recv_tok.value); 870 871 if (GSS_ERROR(status)) { 872 /* Start again with the next method in the list */ 873 userauth(authctxt, NULL); 874 return; 875 } 876} 877 878/* ARGSUSED */ 879void 880input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 881{ 882 Authctxt *authctxt = ctxt; 883 Gssctxt *gssctxt; 884 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 885 gss_buffer_desc recv_tok; 886 OM_uint32 status, ms; 887 u_int len; 888 889 if (authctxt == NULL) 890 fatal("input_gssapi_response: no authentication context"); 891 gssctxt = authctxt->methoddata; 892 893 recv_tok.value = packet_get_string(&len); 894 recv_tok.length = len; 895 896 packet_check_eom(); 897 898 /* Stick it into GSSAPI and see what it says */ 899 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 900 &recv_tok, &send_tok, NULL); 901 902 xfree(recv_tok.value); 903 gss_release_buffer(&ms, &send_tok); 904 905 /* Server will be returning a failed packet after this one */ 906} 907 908/* ARGSUSED */ 909void 910input_gssapi_error(int type, u_int32_t plen, void *ctxt) 911{ 912 OM_uint32 maj, min; 913 char *msg; 914 char *lang; 915 916 maj=packet_get_int(); 917 min=packet_get_int(); 918 msg=packet_get_string(NULL); 919 lang=packet_get_string(NULL); 920 921 packet_check_eom(); 922 923 debug("Server GSSAPI Error:\n%s", msg); 924 xfree(msg); 925 xfree(lang); 926} 927 928int 929userauth_gsskeyex(Authctxt *authctxt) 930{ 931 Buffer b; 932 gss_buffer_desc gssbuf; 933 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 934 OM_uint32 ms; 935 936 static int attempt = 0; 937 if (attempt++ >= 1) 938 return (0); 939 940 if (gss_kex_context == NULL) { 941 debug("No valid Key exchange context"); 942 return (0); 943 } 944 945 ssh_gssapi_buildmic(&b, authctxt->server_user, authctxt->service, 946 "gssapi-keyex"); 947 948 gssbuf.value = buffer_ptr(&b); 949 gssbuf.length = buffer_len(&b); 950 951 if (GSS_ERROR(ssh_gssapi_sign(gss_kex_context, &gssbuf, &mic))) { 952 buffer_free(&b); 953 return (0); 954 } 955 956 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_string(mic.value, mic.length); 961 packet_send(); 962 963 buffer_free(&b); 964 gss_release_buffer(&ms, &mic); 965 966 return (1); 967} 968 969#endif /* GSSAPI */ 970 971int 972userauth_none(Authctxt *authctxt) 973{ 974 /* initial userauth request */ 975 packet_start(SSH2_MSG_USERAUTH_REQUEST); 976 packet_put_cstring(authctxt->server_user); 977 packet_put_cstring(authctxt->service); 978 packet_put_cstring(authctxt->method->name); 979 packet_send(); 980 return 1; 981} 982 983int 984userauth_passwd(Authctxt *authctxt) 985{ 986 static int attempt = 0; 987 char prompt[150]; 988 char *password; 989 const char *host = options.host_key_alias ? options.host_key_alias : 990 authctxt->host; 991 992 if (attempt++ >= options.number_of_password_prompts) 993 return 0; 994 995 if (attempt != 1) 996 error("Permission denied, please try again."); 997 998 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 999 authctxt->server_user, host); 1000 password = read_passphrase(prompt, 0); 1001 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1002 packet_put_cstring(authctxt->server_user); 1003 packet_put_cstring(authctxt->service); 1004 packet_put_cstring(authctxt->method->name); 1005 packet_put_char(0); 1006 packet_put_cstring(password); 1007 memset(password, 0, strlen(password)); 1008 xfree(password); 1009 packet_add_padding(64); 1010 packet_send(); 1011 1012 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1013 &input_userauth_passwd_changereq); 1014 1015 return 1; 1016} 1017 1018/* 1019 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 1020 */ 1021/* ARGSUSED */ 1022void 1023input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 1024{ 1025 Authctxt *authctxt = ctxt; 1026 char *info, *lang, *password = NULL, *retype = NULL; 1027 char prompt[150]; 1028 const char *host = options.host_key_alias ? options.host_key_alias : 1029 authctxt->host; 1030 1031 debug2("input_userauth_passwd_changereq"); 1032 1033 if (authctxt == NULL) 1034 fatal("input_userauth_passwd_changereq: " 1035 "no authentication context"); 1036 1037 info = packet_get_string(NULL); 1038 lang = packet_get_string(NULL); 1039 if (strlen(info) > 0) 1040 logit("%s", info); 1041 xfree(info); 1042 xfree(lang); 1043 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1044 packet_put_cstring(authctxt->server_user); 1045 packet_put_cstring(authctxt->service); 1046 packet_put_cstring(authctxt->method->name); 1047 packet_put_char(1); /* additional info */ 1048 snprintf(prompt, sizeof(prompt), 1049 "Enter %.30s@%.128s's old password: ", 1050 authctxt->server_user, host); 1051 password = read_passphrase(prompt, 0); 1052 packet_put_cstring(password); 1053 memset(password, 0, strlen(password)); 1054 xfree(password); 1055 password = NULL; 1056 while (password == NULL) { 1057 snprintf(prompt, sizeof(prompt), 1058 "Enter %.30s@%.128s's new password: ", 1059 authctxt->server_user, host); 1060 password = read_passphrase(prompt, RP_ALLOW_EOF); 1061 if (password == NULL) { 1062 /* bail out */ 1063 return; 1064 } 1065 snprintf(prompt, sizeof(prompt), 1066 "Retype %.30s@%.128s's new password: ", 1067 authctxt->server_user, host); 1068 retype = read_passphrase(prompt, 0); 1069 if (strcmp(password, retype) != 0) { 1070 memset(password, 0, strlen(password)); 1071 xfree(password); 1072 logit("Mismatch; try again, EOF to quit."); 1073 password = NULL; 1074 } 1075 memset(retype, 0, strlen(retype)); 1076 xfree(retype); 1077 } 1078 packet_put_cstring(password); 1079 memset(password, 0, strlen(password)); 1080 xfree(password); 1081 packet_add_padding(64); 1082 packet_send(); 1083 1084 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1085 &input_userauth_passwd_changereq); 1086} 1087 1088#ifdef JPAKE 1089static char * 1090pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 1091{ 1092 /* OpenBSD crypt(3) handles all of these */ 1093 if (strcmp(crypt_scheme, "crypt") == 0 || 1094 strcmp(crypt_scheme, "bcrypt") == 0 || 1095 strcmp(crypt_scheme, "md5crypt") == 0 || 1096 strcmp(crypt_scheme, "crypt-extended") == 0) 1097 return xstrdup(crypt(password, salt)); 1098 error("%s: unsupported password encryption scheme \"%.100s\"", 1099 __func__, crypt_scheme); 1100 return NULL; 1101} 1102 1103static BIGNUM * 1104jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 1105 const char *salt) 1106{ 1107 char prompt[256], *password, *crypted; 1108 u_char *secret; 1109 u_int secret_len; 1110 BIGNUM *ret; 1111 1112 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 1113 authctxt->server_user, authctxt->host); 1114 password = read_passphrase(prompt, 0); 1115 1116 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 1117 logit("Disabling %s authentication", authctxt->method->name); 1118 authctxt->method->enabled = NULL; 1119 /* Continue with an empty password to fail gracefully */ 1120 crypted = xstrdup(""); 1121 } 1122 1123#ifdef JPAKE_DEBUG 1124 debug3("%s: salt = %s", __func__, salt); 1125 debug3("%s: scheme = %s", __func__, crypt_scheme); 1126 debug3("%s: crypted = %s", __func__, crypted); 1127#endif 1128 1129 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 1130 &secret, &secret_len) != 0) 1131 fatal("%s: hash_buffer", __func__); 1132 1133 bzero(password, strlen(password)); 1134 bzero(crypted, strlen(crypted)); 1135 xfree(password); 1136 xfree(crypted); 1137 1138 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 1139 fatal("%s: BN_bin2bn (secret)", __func__); 1140 bzero(secret, secret_len); 1141 xfree(secret); 1142 1143 return ret; 1144} 1145 1146/* ARGSUSED */ 1147void 1148input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 1149{ 1150 Authctxt *authctxt = ctxt; 1151 struct jpake_ctx *pctx = authctxt->methoddata; 1152 u_char *x3_proof, *x4_proof, *x2_s_proof; 1153 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 1154 char *crypt_scheme, *salt; 1155 1156 /* Disable this message */ 1157 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 1158 1159 if ((pctx->g_x3 = BN_new()) == NULL || 1160 (pctx->g_x4 = BN_new()) == NULL) 1161 fatal("%s: BN_new", __func__); 1162 1163 /* Fetch step 1 values */ 1164 crypt_scheme = packet_get_string(NULL); 1165 salt = packet_get_string(NULL); 1166 pctx->server_id = packet_get_string(&pctx->server_id_len); 1167 packet_get_bignum2(pctx->g_x3); 1168 packet_get_bignum2(pctx->g_x4); 1169 x3_proof = packet_get_string(&x3_proof_len); 1170 x4_proof = packet_get_string(&x4_proof_len); 1171 packet_check_eom(); 1172 1173 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1174 1175 /* Obtain password and derive secret */ 1176 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1177 bzero(crypt_scheme, strlen(crypt_scheme)); 1178 bzero(salt, strlen(salt)); 1179 xfree(crypt_scheme); 1180 xfree(salt); 1181 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1182 1183 /* Calculate step 2 values */ 1184 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1185 pctx->g_x3, pctx->g_x4, pctx->x2, 1186 pctx->server_id, pctx->server_id_len, 1187 pctx->client_id, pctx->client_id_len, 1188 x3_proof, x3_proof_len, 1189 x4_proof, x4_proof_len, 1190 &pctx->a, 1191 &x2_s_proof, &x2_s_proof_len); 1192 1193 bzero(x3_proof, x3_proof_len); 1194 bzero(x4_proof, x4_proof_len); 1195 xfree(x3_proof); 1196 xfree(x4_proof); 1197 1198 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1199 1200 /* Send values for step 2 */ 1201 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1202 packet_put_bignum2(pctx->a); 1203 packet_put_string(x2_s_proof, x2_s_proof_len); 1204 packet_send(); 1205 1206 bzero(x2_s_proof, x2_s_proof_len); 1207 xfree(x2_s_proof); 1208 1209 /* Expect step 2 packet from peer */ 1210 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1211 input_userauth_jpake_server_step2); 1212} 1213 1214/* ARGSUSED */ 1215void 1216input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1217{ 1218 Authctxt *authctxt = ctxt; 1219 struct jpake_ctx *pctx = authctxt->methoddata; 1220 u_char *x4_s_proof; 1221 u_int x4_s_proof_len; 1222 1223 /* Disable this message */ 1224 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1225 1226 if ((pctx->b = BN_new()) == NULL) 1227 fatal("%s: BN_new", __func__); 1228 1229 /* Fetch step 2 values */ 1230 packet_get_bignum2(pctx->b); 1231 x4_s_proof = packet_get_string(&x4_s_proof_len); 1232 packet_check_eom(); 1233 1234 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1235 1236 /* Derive shared key and calculate confirmation hash */ 1237 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1238 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1239 pctx->client_id, pctx->client_id_len, 1240 pctx->server_id, pctx->server_id_len, 1241 session_id2, session_id2_len, 1242 x4_s_proof, x4_s_proof_len, 1243 &pctx->k, 1244 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1245 1246 bzero(x4_s_proof, x4_s_proof_len); 1247 xfree(x4_s_proof); 1248 1249 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1250 1251 /* Send key confirmation proof */ 1252 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1253 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1254 packet_send(); 1255 1256 /* Expect confirmation from peer */ 1257 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1258 input_userauth_jpake_server_confirm); 1259} 1260 1261/* ARGSUSED */ 1262void 1263input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1264{ 1265 Authctxt *authctxt = ctxt; 1266 struct jpake_ctx *pctx = authctxt->methoddata; 1267 1268 /* Disable this message */ 1269 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1270 1271 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1272 packet_check_eom(); 1273 1274 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1275 1276 /* Verify expected confirmation hash */ 1277 if (jpake_check_confirm(pctx->k, 1278 pctx->server_id, pctx->server_id_len, 1279 session_id2, session_id2_len, 1280 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1281 debug("%s: %s success", __func__, authctxt->method->name); 1282 else { 1283 debug("%s: confirmation mismatch", __func__); 1284 /* XXX stash this so if auth succeeds then we can warn/kill */ 1285 } 1286 1287 userauth_jpake_cleanup(authctxt); 1288} 1289#endif /* JPAKE */ 1290 1291static int 1292identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1293 u_char *data, u_int datalen) 1294{ 1295 Key *prv; 1296 int ret; 1297 1298 /* the agent supports this key */ 1299 if (id->ac) 1300 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1301 data, datalen)); 1302 /* 1303 * we have already loaded the private key or 1304 * the private key is stored in external hardware 1305 */ 1306 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1307 return (key_sign(id->key, sigp, lenp, data, datalen)); 1308 /* load the private key from the file */ 1309 if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL) 1310 return (-1); 1311 ret = key_sign(prv, sigp, lenp, data, datalen); 1312 key_free(prv); 1313 return (ret); 1314} 1315 1316static int 1317sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1318{ 1319 Buffer b; 1320 u_char *blob, *signature; 1321 u_int bloblen, slen; 1322 u_int skip = 0; 1323 int ret = -1; 1324 int have_sig = 1; 1325 char *fp; 1326 1327 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1328 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1329 xfree(fp); 1330 1331 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1332 /* we cannot handle this key */ 1333 debug3("sign_and_send_pubkey: cannot handle key"); 1334 return 0; 1335 } 1336 /* data to be signed */ 1337 buffer_init(&b); 1338 if (datafellows & SSH_OLD_SESSIONID) { 1339 buffer_append(&b, session_id2, session_id2_len); 1340 skip = session_id2_len; 1341 } else { 1342 buffer_put_string(&b, session_id2, session_id2_len); 1343 skip = buffer_len(&b); 1344 } 1345 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1346 buffer_put_cstring(&b, authctxt->server_user); 1347 buffer_put_cstring(&b, 1348 datafellows & SSH_BUG_PKSERVICE ? 1349 "ssh-userauth" : 1350 authctxt->service); 1351 if (datafellows & SSH_BUG_PKAUTH) { 1352 buffer_put_char(&b, have_sig); 1353 } else { 1354 buffer_put_cstring(&b, authctxt->method->name); 1355 buffer_put_char(&b, have_sig); 1356 buffer_put_cstring(&b, key_ssh_name(id->key)); 1357 } 1358 buffer_put_string(&b, blob, bloblen); 1359 1360 /* generate signature */ 1361 ret = identity_sign(id, &signature, &slen, 1362 buffer_ptr(&b), buffer_len(&b)); 1363 if (ret == -1) { 1364 xfree(blob); 1365 buffer_free(&b); 1366 return 0; 1367 } 1368#ifdef DEBUG_PK 1369 buffer_dump(&b); 1370#endif 1371 if (datafellows & SSH_BUG_PKSERVICE) { 1372 buffer_clear(&b); 1373 buffer_append(&b, session_id2, session_id2_len); 1374 skip = session_id2_len; 1375 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1376 buffer_put_cstring(&b, authctxt->server_user); 1377 buffer_put_cstring(&b, authctxt->service); 1378 buffer_put_cstring(&b, authctxt->method->name); 1379 buffer_put_char(&b, have_sig); 1380 if (!(datafellows & SSH_BUG_PKAUTH)) 1381 buffer_put_cstring(&b, key_ssh_name(id->key)); 1382 buffer_put_string(&b, blob, bloblen); 1383 } 1384 xfree(blob); 1385 1386 /* append signature */ 1387 buffer_put_string(&b, signature, slen); 1388 xfree(signature); 1389 1390 /* skip session id and packet type */ 1391 if (buffer_len(&b) < skip + 1) 1392 fatal("userauth_pubkey: internal error"); 1393 buffer_consume(&b, skip + 1); 1394 1395 /* put remaining data from buffer into packet */ 1396 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1397 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1398 buffer_free(&b); 1399 packet_send(); 1400 1401 return 1; 1402} 1403 1404static int 1405send_pubkey_test(Authctxt *authctxt, Identity *id) 1406{ 1407 u_char *blob; 1408 u_int bloblen, have_sig = 0; 1409 1410 debug3("send_pubkey_test"); 1411 1412 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1413 /* we cannot handle this key */ 1414 debug3("send_pubkey_test: cannot handle key"); 1415 return 0; 1416 } 1417 /* register callback for USERAUTH_PK_OK message */ 1418 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1419 1420 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1421 packet_put_cstring(authctxt->server_user); 1422 packet_put_cstring(authctxt->service); 1423 packet_put_cstring(authctxt->method->name); 1424 packet_put_char(have_sig); 1425 if (!(datafellows & SSH_BUG_PKAUTH)) 1426 packet_put_cstring(key_ssh_name(id->key)); 1427 packet_put_string(blob, bloblen); 1428 xfree(blob); 1429 packet_send(); 1430 return 1; 1431} 1432 1433static Key * 1434load_identity_file(char *filename, int userprovided) 1435{ 1436 Key *private; 1437 char prompt[300], *passphrase; 1438 int perm_ok = 0, quit, i; 1439 struct stat st; 1440 1441 if (stat(filename, &st) < 0) { 1442 (userprovided ? logit : debug3)("no such identity: %s: %s", 1443 filename, strerror(errno)); 1444 return NULL; 1445 } 1446 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1447 if (!perm_ok) 1448 return NULL; 1449 if (private == NULL) { 1450 if (options.batch_mode) 1451 return NULL; 1452 snprintf(prompt, sizeof prompt, 1453 "Enter passphrase for key '%.100s': ", filename); 1454 for (i = 0; i < options.number_of_password_prompts; i++) { 1455#ifdef __APPLE_KEYCHAIN__ 1456 passphrase = keychain_read_passphrase(filename, options.ask_pass_gui); 1457 if (passphrase == NULL) 1458#endif 1459 passphrase = read_passphrase(prompt, 0); 1460 if (strcmp(passphrase, "") != 0) { 1461 private = key_load_private_type(KEY_UNSPEC, 1462 filename, passphrase, NULL, NULL); 1463 quit = 0; 1464 } else { 1465 debug2("no passphrase given, try next key"); 1466 quit = 1; 1467 } 1468 memset(passphrase, 0, strlen(passphrase)); 1469 xfree(passphrase); 1470 if (private != NULL || quit) 1471 break; 1472 debug2("bad passphrase given, try again..."); 1473 } 1474 } 1475 return private; 1476} 1477 1478/* 1479 * try keys in the following order: 1480 * 1. agent keys that are found in the config file 1481 * 2. other agent keys 1482 * 3. keys that are only listed in the config file 1483 */ 1484static void 1485pubkey_prepare(Authctxt *authctxt) 1486{ 1487 Identity *id, *id2, *tmp; 1488 Idlist agent, files, *preferred; 1489 Key *key; 1490 AuthenticationConnection *ac; 1491 char *comment; 1492 int i, found; 1493 1494 TAILQ_INIT(&agent); /* keys from the agent */ 1495 TAILQ_INIT(&files); /* keys from the config file */ 1496 preferred = &authctxt->keys; 1497 TAILQ_INIT(preferred); /* preferred order of keys */ 1498 1499 /* list of keys stored in the filesystem and PKCS#11 */ 1500 for (i = 0; i < options.num_identity_files; i++) { 1501 key = options.identity_keys[i]; 1502 if (key && key->type == KEY_RSA1) 1503 continue; 1504 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1505 continue; 1506 options.identity_keys[i] = NULL; 1507 id = xcalloc(1, sizeof(*id)); 1508 id->key = key; 1509 id->filename = xstrdup(options.identity_files[i]); 1510 id->userprovided = options.identity_file_userprovided[i]; 1511 TAILQ_INSERT_TAIL(&files, id, next); 1512 } 1513 /* Prefer PKCS11 keys that are explicitly listed */ 1514 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1515 if (id->key == NULL || (id->key->flags & KEY_FLAG_EXT) == 0) 1516 continue; 1517 found = 0; 1518 TAILQ_FOREACH(id2, &files, next) { 1519 if (id2->key == NULL || 1520 (id2->key->flags & KEY_FLAG_EXT) != 0) 1521 continue; 1522 if (key_equal(id->key, id2->key)) { 1523 TAILQ_REMOVE(&files, id, next); 1524 TAILQ_INSERT_TAIL(preferred, id, next); 1525 found = 1; 1526 break; 1527 } 1528 } 1529 /* If IdentitiesOnly set and key not found then don't use it */ 1530 if (!found && options.identities_only) { 1531 TAILQ_REMOVE(&files, id, next); 1532 bzero(id, sizeof(id)); 1533 free(id); 1534 } 1535 } 1536 /* list of keys supported by the agent */ 1537 if ((ac = ssh_get_authentication_connection())) { 1538 for (key = ssh_get_first_identity(ac, &comment, 2); 1539 key != NULL; 1540 key = ssh_get_next_identity(ac, &comment, 2)) { 1541 found = 0; 1542 TAILQ_FOREACH(id, &files, next) { 1543 /* agent keys from the config file are preferred */ 1544 if (key_equal(key, id->key)) { 1545 key_free(key); 1546 xfree(comment); 1547 TAILQ_REMOVE(&files, id, next); 1548 TAILQ_INSERT_TAIL(preferred, id, next); 1549 id->ac = ac; 1550 found = 1; 1551 break; 1552 } 1553 } 1554 if (!found && !options.identities_only) { 1555 id = xcalloc(1, sizeof(*id)); 1556 id->key = key; 1557 id->filename = comment; 1558 id->ac = ac; 1559 TAILQ_INSERT_TAIL(&agent, id, next); 1560 } 1561 } 1562 /* append remaining agent keys */ 1563 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1564 TAILQ_REMOVE(&agent, id, next); 1565 TAILQ_INSERT_TAIL(preferred, id, next); 1566 } 1567 authctxt->agent = ac; 1568 } 1569 /* append remaining keys from the config file */ 1570 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1571 TAILQ_REMOVE(&files, id, next); 1572 TAILQ_INSERT_TAIL(preferred, id, next); 1573 } 1574 TAILQ_FOREACH(id, preferred, next) { 1575 debug2("key: %s (%p),%s", id->filename, id->key, 1576 id->userprovided ? " explicit" : ""); 1577 } 1578} 1579 1580static void 1581pubkey_cleanup(Authctxt *authctxt) 1582{ 1583 Identity *id; 1584 1585 if (authctxt->agent != NULL) 1586 ssh_close_authentication_connection(authctxt->agent); 1587 for (id = TAILQ_FIRST(&authctxt->keys); id; 1588 id = TAILQ_FIRST(&authctxt->keys)) { 1589 TAILQ_REMOVE(&authctxt->keys, id, next); 1590 if (id->key) 1591 key_free(id->key); 1592 if (id->filename) 1593 xfree(id->filename); 1594 xfree(id); 1595 } 1596} 1597 1598int 1599userauth_pubkey(Authctxt *authctxt) 1600{ 1601 Identity *id; 1602 int sent = 0; 1603 1604 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1605 if (id->tried++) 1606 return (0); 1607 /* move key to the end of the queue */ 1608 TAILQ_REMOVE(&authctxt->keys, id, next); 1609 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1610 /* 1611 * send a test message if we have the public key. for 1612 * encrypted keys we cannot do this and have to load the 1613 * private key instead 1614 */ 1615 if (id->key && id->key->type != KEY_RSA1) { 1616 debug("Offering %s public key: %s", key_type(id->key), 1617 id->filename); 1618 sent = send_pubkey_test(authctxt, id); 1619 } else if (id->key == NULL) { 1620 debug("Trying private key: %s", id->filename); 1621 id->key = load_identity_file(id->filename, 1622 id->userprovided); 1623 if (id->key != NULL) { 1624 id->isprivate = 1; 1625 sent = sign_and_send_pubkey(authctxt, id); 1626 key_free(id->key); 1627 id->key = NULL; 1628 } 1629 } 1630 if (sent) 1631 return (sent); 1632 } 1633 return (0); 1634} 1635 1636/* 1637 * Send userauth request message specifying keyboard-interactive method. 1638 */ 1639int 1640userauth_kbdint(Authctxt *authctxt) 1641{ 1642 static int attempt = 0; 1643 1644 if (attempt++ >= options.number_of_password_prompts) 1645 return 0; 1646 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1647 if (attempt > 1 && !authctxt->info_req_seen) { 1648 debug3("userauth_kbdint: disable: no info_req_seen"); 1649 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1650 return 0; 1651 } 1652 1653 debug2("userauth_kbdint"); 1654 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1655 packet_put_cstring(authctxt->server_user); 1656 packet_put_cstring(authctxt->service); 1657 packet_put_cstring(authctxt->method->name); 1658 packet_put_cstring(""); /* lang */ 1659 packet_put_cstring(options.kbd_interactive_devices ? 1660 options.kbd_interactive_devices : ""); 1661 packet_send(); 1662 1663 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1664 return 1; 1665} 1666 1667/* 1668 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1669 */ 1670void 1671input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1672{ 1673 Authctxt *authctxt = ctxt; 1674 char *name, *inst, *lang, *prompt, *response; 1675 u_int num_prompts, i; 1676 int echo = 0; 1677 1678 debug2("input_userauth_info_req"); 1679 1680 if (authctxt == NULL) 1681 fatal("input_userauth_info_req: no authentication context"); 1682 1683 authctxt->info_req_seen = 1; 1684 1685 name = packet_get_string(NULL); 1686 inst = packet_get_string(NULL); 1687 lang = packet_get_string(NULL); 1688 if (strlen(name) > 0) 1689 logit("%s", name); 1690 if (strlen(inst) > 0) 1691 logit("%s", inst); 1692 xfree(name); 1693 xfree(inst); 1694 xfree(lang); 1695 1696 num_prompts = packet_get_int(); 1697 /* 1698 * Begin to build info response packet based on prompts requested. 1699 * We commit to providing the correct number of responses, so if 1700 * further on we run into a problem that prevents this, we have to 1701 * be sure and clean this up and send a correct error response. 1702 */ 1703 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1704 packet_put_int(num_prompts); 1705 1706 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1707 for (i = 0; i < num_prompts; i++) { 1708 prompt = packet_get_string(NULL); 1709 echo = packet_get_char(); 1710 1711 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1712 1713 packet_put_cstring(response); 1714 memset(response, 0, strlen(response)); 1715 xfree(response); 1716 xfree(prompt); 1717 } 1718 packet_check_eom(); /* done with parsing incoming message. */ 1719 1720 packet_add_padding(64); 1721 packet_send(); 1722} 1723 1724static int 1725ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1726 u_char *data, u_int datalen) 1727{ 1728 Buffer b; 1729 struct stat st; 1730 pid_t pid; 1731 int to[2], from[2], status, version = 2; 1732 1733 debug2("ssh_keysign called"); 1734 1735 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1736 error("ssh_keysign: not installed: %s", strerror(errno)); 1737 return -1; 1738 } 1739 if (fflush(stdout) != 0) 1740 error("ssh_keysign: fflush: %s", strerror(errno)); 1741 if (pipe(to) < 0) { 1742 error("ssh_keysign: pipe: %s", strerror(errno)); 1743 return -1; 1744 } 1745 if (pipe(from) < 0) { 1746 error("ssh_keysign: pipe: %s", strerror(errno)); 1747 return -1; 1748 } 1749 if ((pid = fork()) < 0) { 1750 error("ssh_keysign: fork: %s", strerror(errno)); 1751 return -1; 1752 } 1753 if (pid == 0) { 1754 /* keep the socket on exec */ 1755 fcntl(packet_get_connection_in(), F_SETFD, 0); 1756 permanently_drop_suid(getuid()); 1757 close(from[0]); 1758 if (dup2(from[1], STDOUT_FILENO) < 0) 1759 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1760 close(to[1]); 1761 if (dup2(to[0], STDIN_FILENO) < 0) 1762 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1763 close(from[1]); 1764 close(to[0]); 1765 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1766 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1767 strerror(errno)); 1768 } 1769 close(from[1]); 1770 close(to[0]); 1771 1772 buffer_init(&b); 1773 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1774 buffer_put_string(&b, data, datalen); 1775 if (ssh_msg_send(to[1], version, &b) == -1) 1776 fatal("ssh_keysign: couldn't send request"); 1777 1778 if (ssh_msg_recv(from[0], &b) < 0) { 1779 error("ssh_keysign: no reply"); 1780 buffer_free(&b); 1781 return -1; 1782 } 1783 close(from[0]); 1784 close(to[1]); 1785 1786 while (waitpid(pid, &status, 0) < 0) 1787 if (errno != EINTR) 1788 break; 1789 1790 if (buffer_get_char(&b) != version) { 1791 error("ssh_keysign: bad version"); 1792 buffer_free(&b); 1793 return -1; 1794 } 1795 *sigp = buffer_get_string(&b, lenp); 1796 buffer_free(&b); 1797 1798 return 0; 1799} 1800 1801int 1802userauth_hostbased(Authctxt *authctxt) 1803{ 1804 Key *private = NULL; 1805 Sensitive *sensitive = authctxt->sensitive; 1806 Buffer b; 1807 u_char *signature, *blob; 1808 char *chost, *pkalg, *p; 1809 const char *service; 1810 u_int blen, slen; 1811 int ok, i, found = 0; 1812 1813 /* check for a useful key */ 1814 for (i = 0; i < sensitive->nkeys; i++) { 1815 private = sensitive->keys[i]; 1816 if (private && private->type != KEY_RSA1) { 1817 found = 1; 1818 /* we take and free the key */ 1819 sensitive->keys[i] = NULL; 1820 break; 1821 } 1822 } 1823 if (!found) { 1824 debug("No more client hostkeys for hostbased authentication."); 1825 return 0; 1826 } 1827 if (key_to_blob(private, &blob, &blen) == 0) { 1828 key_free(private); 1829 return 0; 1830 } 1831 /* figure out a name for the client host */ 1832 p = get_local_name(packet_get_connection_in()); 1833 if (p == NULL) { 1834 error("userauth_hostbased: cannot get local ipaddr/name"); 1835 key_free(private); 1836 xfree(blob); 1837 return 0; 1838 } 1839 xasprintf(&chost, "%s.", p); 1840 debug2("userauth_hostbased: chost %s", chost); 1841 xfree(p); 1842 1843 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1844 authctxt->service; 1845 pkalg = xstrdup(key_ssh_name(private)); 1846 buffer_init(&b); 1847 /* construct data */ 1848 buffer_put_string(&b, session_id2, session_id2_len); 1849 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1850 buffer_put_cstring(&b, authctxt->server_user); 1851 buffer_put_cstring(&b, service); 1852 buffer_put_cstring(&b, authctxt->method->name); 1853 buffer_put_cstring(&b, pkalg); 1854 buffer_put_string(&b, blob, blen); 1855 buffer_put_cstring(&b, chost); 1856 buffer_put_cstring(&b, authctxt->local_user); 1857#ifdef DEBUG_PK 1858 buffer_dump(&b); 1859#endif 1860 if (sensitive->external_keysign) 1861 ok = ssh_keysign(private, &signature, &slen, 1862 buffer_ptr(&b), buffer_len(&b)); 1863 else 1864 ok = key_sign(private, &signature, &slen, 1865 buffer_ptr(&b), buffer_len(&b)); 1866 key_free(private); 1867 buffer_free(&b); 1868 if (ok != 0) { 1869 error("key_sign failed"); 1870 xfree(chost); 1871 xfree(pkalg); 1872 xfree(blob); 1873 return 0; 1874 } 1875 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1876 packet_put_cstring(authctxt->server_user); 1877 packet_put_cstring(authctxt->service); 1878 packet_put_cstring(authctxt->method->name); 1879 packet_put_cstring(pkalg); 1880 packet_put_string(blob, blen); 1881 packet_put_cstring(chost); 1882 packet_put_cstring(authctxt->local_user); 1883 packet_put_string(signature, slen); 1884 memset(signature, 's', slen); 1885 xfree(signature); 1886 xfree(chost); 1887 xfree(pkalg); 1888 xfree(blob); 1889 1890 packet_send(); 1891 return 1; 1892} 1893 1894#ifdef JPAKE 1895int 1896userauth_jpake(Authctxt *authctxt) 1897{ 1898 struct jpake_ctx *pctx; 1899 u_char *x1_proof, *x2_proof; 1900 u_int x1_proof_len, x2_proof_len; 1901 static int attempt = 0; /* XXX share with userauth_password's? */ 1902 1903 if (attempt++ >= options.number_of_password_prompts) 1904 return 0; 1905 if (attempt != 1) 1906 error("Permission denied, please try again."); 1907 1908 if (authctxt->methoddata != NULL) 1909 fatal("%s: authctxt->methoddata already set (%p)", 1910 __func__, authctxt->methoddata); 1911 1912 authctxt->methoddata = pctx = jpake_new(); 1913 1914 /* 1915 * Send request immediately, to get the protocol going while 1916 * we do the initial computations. 1917 */ 1918 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1919 packet_put_cstring(authctxt->server_user); 1920 packet_put_cstring(authctxt->service); 1921 packet_put_cstring(authctxt->method->name); 1922 packet_send(); 1923 packet_write_wait(); 1924 1925 jpake_step1(pctx->grp, 1926 &pctx->client_id, &pctx->client_id_len, 1927 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1928 &x1_proof, &x1_proof_len, 1929 &x2_proof, &x2_proof_len); 1930 1931 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1932 1933 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1934 packet_put_string(pctx->client_id, pctx->client_id_len); 1935 packet_put_bignum2(pctx->g_x1); 1936 packet_put_bignum2(pctx->g_x2); 1937 packet_put_string(x1_proof, x1_proof_len); 1938 packet_put_string(x2_proof, x2_proof_len); 1939 packet_send(); 1940 1941 bzero(x1_proof, x1_proof_len); 1942 bzero(x2_proof, x2_proof_len); 1943 xfree(x1_proof); 1944 xfree(x2_proof); 1945 1946 /* Expect step 1 packet from peer */ 1947 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1948 input_userauth_jpake_server_step1); 1949 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1950 &input_userauth_success_unexpected); 1951 1952 return 1; 1953} 1954 1955void 1956userauth_jpake_cleanup(Authctxt *authctxt) 1957{ 1958 debug3("%s: clean up", __func__); 1959 if (authctxt->methoddata != NULL) { 1960 jpake_free(authctxt->methoddata); 1961 authctxt->methoddata = NULL; 1962 } 1963 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1964} 1965#endif /* JPAKE */ 1966 1967/* find auth method */ 1968 1969/* 1970 * given auth method name, if configurable options permit this method fill 1971 * in auth_ident field and return true, otherwise return false. 1972 */ 1973static int 1974authmethod_is_enabled(Authmethod *method) 1975{ 1976 if (method == NULL) 1977 return 0; 1978 /* return false if options indicate this method is disabled */ 1979 if (method->enabled == NULL || *method->enabled == 0) 1980 return 0; 1981 /* return false if batch mode is enabled but method needs interactive mode */ 1982 if (method->batch_flag != NULL && *method->batch_flag != 0) 1983 return 0; 1984 return 1; 1985} 1986 1987static Authmethod * 1988authmethod_lookup(const char *name) 1989{ 1990 Authmethod *method = NULL; 1991 if (name != NULL) 1992 for (method = authmethods; method->name != NULL; method++) 1993 if (strcmp(name, method->name) == 0) 1994 return method; 1995 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1996 return NULL; 1997} 1998 1999/* XXX internal state */ 2000static Authmethod *current = NULL; 2001static char *supported = NULL; 2002static char *preferred = NULL; 2003 2004/* 2005 * Given the authentication method list sent by the server, return the 2006 * next method we should try. If the server initially sends a nil list, 2007 * use a built-in default list. 2008 */ 2009static Authmethod * 2010authmethod_get(char *authlist) 2011{ 2012 char *name = NULL; 2013 u_int next; 2014 2015 /* Use a suitable default if we're passed a nil list. */ 2016 if (authlist == NULL || strlen(authlist) == 0) 2017 authlist = options.preferred_authentications; 2018 2019 if (supported == NULL || strcmp(authlist, supported) != 0) { 2020 debug3("start over, passed a different list %s", authlist); 2021 if (supported != NULL) 2022 xfree(supported); 2023 supported = xstrdup(authlist); 2024 preferred = options.preferred_authentications; 2025 debug3("preferred %s", preferred); 2026 current = NULL; 2027 } else if (current != NULL && authmethod_is_enabled(current)) 2028 return current; 2029 2030 for (;;) { 2031 if ((name = match_list(preferred, supported, &next)) == NULL) { 2032 debug("No more authentication methods to try."); 2033 current = NULL; 2034 return NULL; 2035 } 2036 preferred += next; 2037 debug3("authmethod_lookup %s", name); 2038 debug3("remaining preferred: %s", preferred); 2039 if ((current = authmethod_lookup(name)) != NULL && 2040 authmethod_is_enabled(current)) { 2041 debug3("authmethod_is_enabled %s", name); 2042 debug("Next authentication method: %s", name); 2043 xfree(name); 2044 return current; 2045 } 2046 } 2047} 2048 2049static char * 2050authmethods_get(void) 2051{ 2052 Authmethod *method = NULL; 2053 Buffer b; 2054 char *list; 2055 2056 buffer_init(&b); 2057 for (method = authmethods; method->name != NULL; method++) { 2058 if (authmethod_is_enabled(method)) { 2059 if (buffer_len(&b) > 0) 2060 buffer_append(&b, ",", 1); 2061 buffer_append(&b, method->name, strlen(method->name)); 2062 } 2063 } 2064 buffer_append(&b, "\0", 1); 2065 list = xstrdup(buffer_ptr(&b)); 2066 buffer_free(&b); 2067 return list; 2068} 2069 2070