1 /* $NetBSD: sshconnect2.c,v 1.15 2013/11/08 19:18:25 christos Exp $ */ 2 /* $OpenBSD: sshconnect2.c,v 1.198 2013/06/05 12:52:38 dtucker Exp $ */ 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 __RCSID("$NetBSD: sshconnect2.c,v 1.15 2013/11/08 19:18:25 christos Exp $"); 30 #include <sys/types.h> 31 #include <sys/socket.h> 32 #include <sys/wait.h> 33 #include <sys/queue.h> 34 #include <sys/stat.h> 35 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <netdb.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <signal.h> 42 #include <pwd.h> 43 #include <unistd.h> 44 #include <vis.h> 45 46 #ifdef KRB5 47 #include <krb5.h> 48 #endif 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 */ 82 extern char *client_version_string; 83 extern char *server_version_string; 84 extern Options options; 85 extern Kex *xxx_kex; 86 87 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */ 88 /* if it is set then prevent the switch to the null cipher */ 89 90 extern int tty_flag; 91 92 /* 93 * SSH2 key exchange 94 */ 95 96 u_char *session_id2 = NULL; 97 u_int session_id2_len = 0; 98 99 char *xxx_host; 100 struct sockaddr *xxx_hostaddr; 101 102 Kex *xxx_kex = NULL; 103 104 static int 105 verify_host_key_callback(Key *hostkey) 106 { 107 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 108 fatal("Host key verification failed."); 109 return 0; 110 } 111 112 static char * 113 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 114 { 115 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 116 size_t maxlen; 117 struct hostkeys *hostkeys; 118 int ktype; 119 u_int i; 120 121 /* Find all hostkeys for this hostname */ 122 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 123 hostkeys = init_hostkeys(); 124 for (i = 0; i < options.num_user_hostfiles; i++) 125 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 126 for (i = 0; i < options.num_system_hostfiles; i++) 127 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 128 129 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 130 maxlen = strlen(avail) + 1; 131 first = xmalloc(maxlen); 132 last = xmalloc(maxlen); 133 *first = *last = '\0'; 134 135 #define ALG_APPEND(to, from) \ 136 do { \ 137 if (*to != '\0') \ 138 strlcat(to, ",", maxlen); \ 139 strlcat(to, from, maxlen); \ 140 } while (0) 141 142 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 143 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) 144 fatal("%s: unknown alg %s", __func__, alg); 145 if (lookup_key_in_hostkeys_by_type(hostkeys, 146 key_type_plain(ktype), NULL)) 147 ALG_APPEND(first, alg); 148 else 149 ALG_APPEND(last, alg); 150 } 151 #undef ALG_APPEND 152 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); 153 if (*first != '\0') 154 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 155 156 free(first); 157 free(last); 158 free(hostname); 159 free(oavail); 160 free_hostkeys(hostkeys); 161 162 return ret; 163 } 164 165 void 166 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 167 { 168 Kex *kex; 169 170 xxx_host = host; 171 xxx_hostaddr = hostaddr; 172 173 if (options.ciphers == (char *)-1) { 174 logit("No valid ciphers for protocol version 2 given, using defaults."); 175 options.ciphers = NULL; 176 } 177 if (options.ciphers != NULL) { 178 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 179 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 180 } 181 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 182 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 183 myproposal[PROPOSAL_ENC_ALGS_STOC] = 184 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 185 if (options.compression) { 186 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 187 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 188 } else { 189 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 190 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 191 } 192 if (options.macs != NULL) { 193 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 194 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 195 } 196 if (options.hostkeyalgorithms != NULL) 197 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 198 options.hostkeyalgorithms; 199 else { 200 /* Prefer algorithms that we already have keys for */ 201 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 202 order_hostkeyalgs(host, hostaddr, port); 203 } 204 if (options.kex_algorithms != NULL) 205 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 206 207 if (options.rekey_limit || options.rekey_interval) 208 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 209 (time_t)options.rekey_interval); 210 211 /* start key exchange */ 212 kex = kex_setup(myproposal); 213 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 214 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 215 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 216 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 217 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 218 kex->client_version_string=client_version_string; 219 kex->server_version_string=server_version_string; 220 kex->verify_host_key=&verify_host_key_callback; 221 222 xxx_kex = kex; 223 224 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 225 226 if (options.use_roaming && !kex->roaming) { 227 debug("Roaming not allowed by server"); 228 options.use_roaming = 0; 229 } 230 231 session_id2 = kex->session_id; 232 session_id2_len = kex->session_id_len; 233 234 #ifdef DEBUG_KEXDH 235 /* send 1st encrypted/maced/compressed message */ 236 packet_start(SSH2_MSG_IGNORE); 237 packet_put_cstring("markus"); 238 packet_send(); 239 packet_write_wait(); 240 #endif 241 } 242 243 /* 244 * Authenticate user 245 */ 246 247 typedef struct Authctxt Authctxt; 248 typedef struct Authmethod Authmethod; 249 typedef struct identity Identity; 250 typedef struct idlist Idlist; 251 252 struct identity { 253 TAILQ_ENTRY(identity) next; 254 AuthenticationConnection *ac; /* set if agent supports key */ 255 Key *key; /* public/private key */ 256 char *filename; /* comment for agent-only keys */ 257 int tried; 258 int isprivate; /* key points to the private key */ 259 int userprovided; 260 }; 261 TAILQ_HEAD(idlist, identity); 262 263 struct Authctxt { 264 const char *server_user; 265 const char *local_user; 266 const char *host; 267 const char *service; 268 Authmethod *method; 269 sig_atomic_t success; 270 char *authlist; 271 /* pubkey */ 272 Idlist keys; 273 AuthenticationConnection *agent; 274 /* hostbased */ 275 Sensitive *sensitive; 276 /* kbd-interactive */ 277 int info_req_seen; 278 /* generic */ 279 void *methoddata; 280 }; 281 struct Authmethod { 282 const char *name; /* string to compare against server's list */ 283 int (*userauth)(Authctxt *authctxt); 284 void (*cleanup)(Authctxt *authctxt); 285 int *enabled; /* flag in option struct that enables method */ 286 int *batch_flag; /* flag in option struct that disables method */ 287 }; 288 289 void input_userauth_success(int, u_int32_t, void *); 290 __dead void input_userauth_success_unexpected(int, u_int32_t, void *); 291 void input_userauth_failure(int, u_int32_t, void *); 292 void input_userauth_banner(int, u_int32_t, void *); 293 __dead void input_userauth_error(int, u_int32_t, void *); 294 void input_userauth_info_req(int, u_int32_t, void *); 295 void input_userauth_pk_ok(int, u_int32_t, void *); 296 void input_userauth_passwd_changereq(int, u_int32_t, void *); 297 void input_userauth_jpake_server_step1(int, u_int32_t, void *); 298 void input_userauth_jpake_server_step2(int, u_int32_t, void *); 299 void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 300 301 int userauth_none(Authctxt *); 302 int userauth_pubkey(Authctxt *); 303 int userauth_passwd(Authctxt *); 304 int userauth_kbdint(Authctxt *); 305 int userauth_hostbased(Authctxt *); 306 int userauth_kerberos(Authctxt *); 307 int userauth_jpake(Authctxt *); 308 309 void userauth_jpake_cleanup(Authctxt *); 310 311 #ifdef GSSAPI 312 int userauth_gssapi(Authctxt *authctxt); 313 void input_gssapi_response(int type, u_int32_t, void *); 314 void input_gssapi_token(int type, u_int32_t, void *); 315 void input_gssapi_hash(int type, u_int32_t, void *); 316 void input_gssapi_error(int, u_int32_t, void *); 317 void input_gssapi_errtok(int, u_int32_t, void *); 318 #endif 319 320 void userauth(Authctxt *, char *); 321 322 static int sign_and_send_pubkey(Authctxt *, Identity *); 323 static void pubkey_prepare(Authctxt *); 324 static void pubkey_cleanup(Authctxt *); 325 static Key *load_identity_file(char *, int); 326 327 static Authmethod *authmethod_get(char *authlist); 328 static Authmethod *authmethod_lookup(const char *name); 329 static char *authmethods_get(void); 330 331 Authmethod authmethods[] = { 332 #ifdef GSSAPI 333 {"gssapi-with-mic", 334 userauth_gssapi, 335 NULL, 336 &options.gss_authentication, 337 NULL}, 338 #endif 339 {"hostbased", 340 userauth_hostbased, 341 NULL, 342 &options.hostbased_authentication, 343 NULL}, 344 #if KRB5 345 {"kerberos-2@ssh.com", 346 userauth_kerberos, 347 NULL, 348 &options.kerberos_authentication, 349 NULL}, 350 #endif 351 {"publickey", 352 userauth_pubkey, 353 NULL, 354 &options.pubkey_authentication, 355 NULL}, 356 #ifdef JPAKE 357 {"jpake-01@openssh.com", 358 userauth_jpake, 359 userauth_jpake_cleanup, 360 &options.zero_knowledge_password_authentication, 361 &options.batch_mode}, 362 #endif 363 {"keyboard-interactive", 364 userauth_kbdint, 365 NULL, 366 &options.kbd_interactive_authentication, 367 &options.batch_mode}, 368 {"password", 369 userauth_passwd, 370 NULL, 371 &options.password_authentication, 372 &options.batch_mode}, 373 {"none", 374 userauth_none, 375 NULL, 376 NULL, 377 NULL}, 378 {NULL, NULL, NULL, NULL, NULL} 379 }; 380 381 void 382 ssh_userauth2(const char *local_user, const char *server_user, char *host, 383 Sensitive *sensitive) 384 { 385 Authctxt authctxt; 386 int type; 387 388 if (options.challenge_response_authentication) 389 options.kbd_interactive_authentication = 1; 390 391 packet_start(SSH2_MSG_SERVICE_REQUEST); 392 packet_put_cstring("ssh-userauth"); 393 packet_send(); 394 debug("SSH2_MSG_SERVICE_REQUEST sent"); 395 packet_write_wait(); 396 type = packet_read(); 397 if (type != SSH2_MSG_SERVICE_ACCEPT) 398 fatal("Server denied authentication request: %d", type); 399 if (packet_remaining() > 0) { 400 char *reply = packet_get_string(NULL); 401 debug2("service_accept: %s", reply); 402 free(reply); 403 } else { 404 debug2("buggy server: service_accept w/o service"); 405 } 406 packet_check_eom(); 407 debug("SSH2_MSG_SERVICE_ACCEPT received"); 408 409 if (options.preferred_authentications == NULL) 410 options.preferred_authentications = authmethods_get(); 411 412 /* setup authentication context */ 413 memset(&authctxt, 0, sizeof(authctxt)); 414 pubkey_prepare(&authctxt); 415 authctxt.server_user = server_user; 416 authctxt.local_user = local_user; 417 authctxt.host = host; 418 authctxt.service = "ssh-connection"; /* service name */ 419 authctxt.success = 0; 420 authctxt.method = authmethod_lookup("none"); 421 authctxt.authlist = NULL; 422 authctxt.methoddata = NULL; 423 authctxt.sensitive = sensitive; 424 authctxt.info_req_seen = 0; 425 if (authctxt.method == NULL) 426 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 427 428 /* initial userauth request */ 429 userauth_none(&authctxt); 430 431 dispatch_init(&input_userauth_error); 432 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 433 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 434 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 435 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 436 437 pubkey_cleanup(&authctxt); 438 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 439 440 /* if the user wants to use the none cipher do it */ 441 /* post authentication and only if the right conditions are met */ 442 /* both of the NONE commands must be true and there must be no */ 443 /* tty allocated */ 444 if ((options.none_switch == 1) && (options.none_enabled == 1)) 445 { 446 if (!tty_flag) /* no null on tty sessions */ 447 { 448 debug("Requesting none rekeying..."); 449 myproposal[PROPOSAL_ENC_ALGS_STOC] = "none"; 450 myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none"; 451 kex_prop2buf(&xxx_kex->my,myproposal); 452 packet_request_rekeying(); 453 fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n"); 454 } 455 else 456 { 457 /* requested NONE cipher when in a tty */ 458 debug("Cannot switch to NONE cipher with tty allocated"); 459 fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n"); 460 } 461 } 462 debug("Authentication succeeded (%s).", authctxt.method->name); 463 } 464 465 void 466 userauth(Authctxt *authctxt, char *authlist) 467 { 468 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 469 authctxt->method->cleanup(authctxt); 470 471 free(authctxt->methoddata); 472 authctxt->methoddata = NULL; 473 if (authlist == NULL) { 474 authlist = authctxt->authlist; 475 } else { 476 free(authctxt->authlist); 477 authctxt->authlist = authlist; 478 } 479 for (;;) { 480 Authmethod *method = authmethod_get(authlist); 481 if (method == NULL) 482 fatal("Permission denied (%s).", authlist); 483 authctxt->method = method; 484 485 /* reset the per method handler */ 486 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 487 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 488 489 /* and try new method */ 490 if (method->userauth(authctxt) != 0) { 491 debug2("we sent a %s packet, wait for reply", method->name); 492 break; 493 } else { 494 debug2("we did not send a packet, disable method"); 495 method->enabled = NULL; 496 } 497 } 498 } 499 500 /* ARGSUSED */ 501 void 502 input_userauth_error(int type, u_int32_t seq, void *ctxt) 503 { 504 fatal("input_userauth_error: bad message during authentication: " 505 "type %d", type); 506 } 507 508 /* ARGSUSED */ 509 void 510 input_userauth_banner(int type, u_int32_t seq, void *ctxt) 511 { 512 char *msg, *raw, *lang; 513 u_int len; 514 515 debug3("input_userauth_banner"); 516 raw = packet_get_string(&len); 517 lang = packet_get_string(NULL); 518 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 519 if (len > 65536) 520 len = 65536; 521 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 522 strvisx(msg, raw, len, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 523 fprintf(stderr, "%s", msg); 524 free(msg); 525 } 526 free(raw); 527 free(lang); 528 } 529 530 /* ARGSUSED */ 531 void 532 input_userauth_success(int type, u_int32_t seq, void *ctxt) 533 { 534 Authctxt *authctxt = ctxt; 535 536 if (authctxt == NULL) 537 fatal("input_userauth_success: no authentication context"); 538 free(authctxt->authlist); 539 authctxt->authlist = NULL; 540 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 541 authctxt->method->cleanup(authctxt); 542 free(authctxt->methoddata); 543 authctxt->methoddata = NULL; 544 authctxt->success = 1; /* break out */ 545 } 546 547 void 548 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 549 { 550 Authctxt *authctxt = ctxt; 551 552 if (authctxt == NULL) 553 fatal("%s: no authentication context", __func__); 554 555 fatal("Unexpected authentication success during %s.", 556 authctxt->method->name); 557 } 558 559 /* ARGSUSED */ 560 void 561 input_userauth_failure(int type, u_int32_t seq, void *ctxt) 562 { 563 Authctxt *authctxt = ctxt; 564 char *authlist = NULL; 565 int partial; 566 567 if (authctxt == NULL) 568 fatal("input_userauth_failure: no authentication context"); 569 570 authlist = packet_get_string(NULL); 571 partial = packet_get_char(); 572 packet_check_eom(); 573 574 if (partial != 0) { 575 logit("Authenticated with partial success."); 576 /* reset state */ 577 pubkey_cleanup(authctxt); 578 pubkey_prepare(authctxt); 579 } 580 debug("Authentications that can continue: %s", authlist); 581 582 userauth(authctxt, authlist); 583 } 584 585 /* ARGSUSED */ 586 void 587 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 588 { 589 Authctxt *authctxt = ctxt; 590 Key *key = NULL; 591 Identity *id = NULL; 592 Buffer b; 593 int pktype, sent = 0; 594 u_int alen, blen; 595 char *pkalg, *fp; 596 u_char *pkblob; 597 598 if (authctxt == NULL) 599 fatal("input_userauth_pk_ok: no authentication context"); 600 if (datafellows & SSH_BUG_PKOK) { 601 /* this is similar to SSH_BUG_PKAUTH */ 602 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 603 pkblob = packet_get_string(&blen); 604 buffer_init(&b); 605 buffer_append(&b, pkblob, blen); 606 pkalg = buffer_get_string(&b, &alen); 607 buffer_free(&b); 608 } else { 609 pkalg = packet_get_string(&alen); 610 pkblob = packet_get_string(&blen); 611 } 612 packet_check_eom(); 613 614 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 615 616 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 617 debug("unknown pkalg %s", pkalg); 618 goto done; 619 } 620 if ((key = key_from_blob(pkblob, blen)) == NULL) { 621 debug("no key from blob. pkalg %s", pkalg); 622 goto done; 623 } 624 if (key->type != pktype) { 625 error("input_userauth_pk_ok: type mismatch " 626 "for decoded key (received %d, expected %d)", 627 key->type, pktype); 628 goto done; 629 } 630 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 631 debug2("input_userauth_pk_ok: fp %s", fp); 632 free(fp); 633 634 /* 635 * search keys in the reverse order, because last candidate has been 636 * moved to the end of the queue. this also avoids confusion by 637 * duplicate keys 638 */ 639 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 640 if (key_equal(key, id->key)) { 641 sent = sign_and_send_pubkey(authctxt, id); 642 break; 643 } 644 } 645 done: 646 if (key != NULL) 647 key_free(key); 648 free(pkalg); 649 free(pkblob); 650 651 /* try another method if we did not send a packet */ 652 if (sent == 0) 653 userauth(authctxt, NULL); 654 } 655 656 #ifdef GSSAPI 657 int 658 userauth_gssapi(Authctxt *authctxt) 659 { 660 Gssctxt *gssctxt = NULL; 661 static gss_OID_set gss_supported = NULL; 662 static u_int mech = 0; 663 OM_uint32 min; 664 int ok = 0; 665 666 /* Try one GSSAPI method at a time, rather than sending them all at 667 * once. */ 668 669 if (gss_supported == NULL) 670 gss_indicate_mechs(&min, &gss_supported); 671 672 /* Check to see if the mechanism is usable before we offer it */ 673 while (mech < gss_supported->count && !ok) { 674 /* My DER encoding requires length<128 */ 675 if (gss_supported->elements[mech].length < 128 && 676 ssh_gssapi_check_mechanism(&gssctxt, 677 &gss_supported->elements[mech], authctxt->host)) { 678 ok = 1; /* Mechanism works */ 679 } else { 680 mech++; 681 } 682 } 683 684 if (!ok) { 685 ssh_gssapi_delete_ctx(&gssctxt); 686 return 0; 687 } 688 689 authctxt->methoddata=(void *)gssctxt; 690 691 packet_start(SSH2_MSG_USERAUTH_REQUEST); 692 packet_put_cstring(authctxt->server_user); 693 packet_put_cstring(authctxt->service); 694 packet_put_cstring(authctxt->method->name); 695 696 packet_put_int(1); 697 698 packet_put_int((gss_supported->elements[mech].length) + 2); 699 packet_put_char(SSH_GSS_OIDTYPE); 700 packet_put_char(gss_supported->elements[mech].length); 701 packet_put_raw(gss_supported->elements[mech].elements, 702 gss_supported->elements[mech].length); 703 704 packet_send(); 705 706 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 707 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 708 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 709 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 710 711 mech++; /* Move along to next candidate */ 712 713 return 1; 714 } 715 716 static OM_uint32 717 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 718 { 719 Authctxt *authctxt = ctxt; 720 Gssctxt *gssctxt = authctxt->methoddata; 721 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 722 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 723 gss_buffer_desc gssbuf; 724 OM_uint32 status, ms, flags; 725 Buffer b; 726 727 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 728 recv_tok, &send_tok, &flags); 729 730 if (send_tok.length > 0) { 731 if (GSS_ERROR(status)) 732 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 733 else 734 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 735 736 packet_put_string(send_tok.value, send_tok.length); 737 packet_send(); 738 gss_release_buffer(&ms, &send_tok); 739 } 740 741 if (status == GSS_S_COMPLETE) { 742 /* send either complete or MIC, depending on mechanism */ 743 if (!(flags & GSS_C_INTEG_FLAG)) { 744 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 745 packet_send(); 746 } else { 747 ssh_gssapi_buildmic(&b, authctxt->server_user, 748 authctxt->service, "gssapi-with-mic"); 749 750 gssbuf.value = buffer_ptr(&b); 751 gssbuf.length = buffer_len(&b); 752 753 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 754 755 if (!GSS_ERROR(status)) { 756 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 757 packet_put_string(mic.value, mic.length); 758 759 packet_send(); 760 } 761 762 buffer_free(&b); 763 gss_release_buffer(&ms, &mic); 764 } 765 } 766 767 return status; 768 } 769 770 /* ARGSUSED */ 771 void 772 input_gssapi_response(int type, u_int32_t plen, void *ctxt) 773 { 774 Authctxt *authctxt = ctxt; 775 Gssctxt *gssctxt; 776 int oidlen; 777 char *oidv; 778 779 if (authctxt == NULL) 780 fatal("input_gssapi_response: no authentication context"); 781 gssctxt = authctxt->methoddata; 782 783 /* Setup our OID */ 784 oidv = packet_get_string(&oidlen); 785 786 if (oidlen <= 2 || 787 oidv[0] != SSH_GSS_OIDTYPE || 788 oidv[1] != oidlen - 2) { 789 free(oidv); 790 debug("Badly encoded mechanism OID received"); 791 userauth(authctxt, NULL); 792 return; 793 } 794 795 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 796 fatal("Server returned different OID than expected"); 797 798 packet_check_eom(); 799 800 free(oidv); 801 802 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 803 /* Start again with next method on list */ 804 debug("Trying to start again"); 805 userauth(authctxt, NULL); 806 return; 807 } 808 } 809 810 /* ARGSUSED */ 811 void 812 input_gssapi_token(int type, u_int32_t plen, void *ctxt) 813 { 814 Authctxt *authctxt = ctxt; 815 gss_buffer_desc recv_tok; 816 OM_uint32 status; 817 u_int slen; 818 819 if (authctxt == NULL) 820 fatal("input_gssapi_response: no authentication context"); 821 822 recv_tok.value = packet_get_string(&slen); 823 recv_tok.length = slen; /* safe typecast */ 824 825 packet_check_eom(); 826 827 status = process_gssapi_token(ctxt, &recv_tok); 828 829 free(recv_tok.value); 830 831 if (GSS_ERROR(status)) { 832 /* Start again with the next method in the list */ 833 userauth(authctxt, NULL); 834 return; 835 } 836 } 837 838 /* ARGSUSED */ 839 void 840 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 841 { 842 Authctxt *authctxt = ctxt; 843 Gssctxt *gssctxt; 844 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 845 gss_buffer_desc recv_tok; 846 OM_uint32 ms; 847 u_int len; 848 849 if (authctxt == NULL) 850 fatal("input_gssapi_response: no authentication context"); 851 gssctxt = authctxt->methoddata; 852 853 recv_tok.value = packet_get_string(&len); 854 recv_tok.length = len; 855 856 packet_check_eom(); 857 858 /* Stick it into GSSAPI and see what it says */ 859 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 860 &recv_tok, &send_tok, NULL); 861 862 free(recv_tok.value); 863 gss_release_buffer(&ms, &send_tok); 864 865 /* Server will be returning a failed packet after this one */ 866 } 867 868 /* ARGSUSED */ 869 void 870 input_gssapi_error(int type, u_int32_t plen, void *ctxt) 871 { 872 char *msg; 873 char *lang; 874 875 /* maj */(void)packet_get_int(); 876 /* min */(void)packet_get_int(); 877 msg=packet_get_string(NULL); 878 lang=packet_get_string(NULL); 879 880 packet_check_eom(); 881 882 debug("Server GSSAPI Error:\n%s", msg); 883 free(msg); 884 free(lang); 885 } 886 #endif /* GSSAPI */ 887 888 int 889 userauth_none(Authctxt *authctxt) 890 { 891 /* initial userauth request */ 892 packet_start(SSH2_MSG_USERAUTH_REQUEST); 893 packet_put_cstring(authctxt->server_user); 894 packet_put_cstring(authctxt->service); 895 packet_put_cstring(authctxt->method->name); 896 packet_send(); 897 return 1; 898 } 899 900 int 901 userauth_passwd(Authctxt *authctxt) 902 { 903 static int attempt = 0; 904 char prompt[150]; 905 char *password; 906 const char *host = options.host_key_alias ? options.host_key_alias : 907 authctxt->host; 908 909 if (attempt++ >= options.number_of_password_prompts) 910 return 0; 911 912 if (attempt != 1) 913 error("Permission denied, please try again."); 914 915 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 916 authctxt->server_user, host); 917 password = read_passphrase(prompt, 0); 918 packet_start(SSH2_MSG_USERAUTH_REQUEST); 919 packet_put_cstring(authctxt->server_user); 920 packet_put_cstring(authctxt->service); 921 packet_put_cstring(authctxt->method->name); 922 packet_put_char(0); 923 packet_put_cstring(password); 924 memset(password, 0, strlen(password)); 925 free(password); 926 packet_add_padding(64); 927 packet_send(); 928 929 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 930 &input_userauth_passwd_changereq); 931 932 return 1; 933 } 934 935 /* 936 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 937 */ 938 /* ARGSUSED */ 939 void 940 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 941 { 942 Authctxt *authctxt = ctxt; 943 char *info, *lang, *password = NULL, *retype = NULL; 944 char prompt[150]; 945 const char *host = options.host_key_alias ? options.host_key_alias : 946 authctxt->host; 947 948 debug2("input_userauth_passwd_changereq"); 949 950 if (authctxt == NULL) 951 fatal("input_userauth_passwd_changereq: " 952 "no authentication context"); 953 954 info = packet_get_string(NULL); 955 lang = packet_get_string(NULL); 956 if (strlen(info) > 0) 957 logit("%s", info); 958 free(info); 959 free(lang); 960 packet_start(SSH2_MSG_USERAUTH_REQUEST); 961 packet_put_cstring(authctxt->server_user); 962 packet_put_cstring(authctxt->service); 963 packet_put_cstring(authctxt->method->name); 964 packet_put_char(1); /* additional info */ 965 snprintf(prompt, sizeof(prompt), 966 "Enter %.30s@%.128s's old password: ", 967 authctxt->server_user, host); 968 password = read_passphrase(prompt, 0); 969 packet_put_cstring(password); 970 memset(password, 0, strlen(password)); 971 free(password); 972 password = NULL; 973 while (password == NULL) { 974 snprintf(prompt, sizeof(prompt), 975 "Enter %.30s@%.128s's new password: ", 976 authctxt->server_user, host); 977 password = read_passphrase(prompt, RP_ALLOW_EOF); 978 if (password == NULL) { 979 /* bail out */ 980 return; 981 } 982 snprintf(prompt, sizeof(prompt), 983 "Retype %.30s@%.128s's new password: ", 984 authctxt->server_user, host); 985 retype = read_passphrase(prompt, 0); 986 if (strcmp(password, retype) != 0) { 987 memset(password, 0, strlen(password)); 988 free(password); 989 logit("Mismatch; try again, EOF to quit."); 990 password = NULL; 991 } 992 memset(retype, 0, strlen(retype)); 993 free(retype); 994 } 995 packet_put_cstring(password); 996 memset(password, 0, strlen(password)); 997 free(password); 998 packet_add_padding(64); 999 packet_send(); 1000 1001 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1002 &input_userauth_passwd_changereq); 1003 } 1004 1005 #ifdef JPAKE 1006 static char * 1007 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 1008 { 1009 /* OpenBSD crypt(3) handles all of these */ 1010 if (strcmp(crypt_scheme, "crypt") == 0 || 1011 strcmp(crypt_scheme, "bcrypt") == 0 || 1012 strcmp(crypt_scheme, "md5crypt") == 0 || 1013 strcmp(crypt_scheme, "crypt-extended") == 0) 1014 return xstrdup(crypt(password, salt)); 1015 error("%s: unsupported password encryption scheme \"%.100s\"", 1016 __func__, crypt_scheme); 1017 return NULL; 1018 } 1019 1020 static BIGNUM * 1021 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 1022 const char *salt) 1023 { 1024 char prompt[256], *password, *crypted; 1025 u_char *secret; 1026 u_int secret_len; 1027 BIGNUM *ret; 1028 1029 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 1030 authctxt->server_user, authctxt->host); 1031 password = read_passphrase(prompt, 0); 1032 1033 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 1034 logit("Disabling %s authentication", authctxt->method->name); 1035 authctxt->method->enabled = NULL; 1036 /* Continue with an empty password to fail gracefully */ 1037 crypted = xstrdup(""); 1038 } 1039 1040 #ifdef JPAKE_DEBUG 1041 debug3("%s: salt = %s", __func__, salt); 1042 debug3("%s: scheme = %s", __func__, crypt_scheme); 1043 debug3("%s: crypted = %s", __func__, crypted); 1044 #endif 1045 1046 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 1047 &secret, &secret_len) != 0) 1048 fatal("%s: hash_buffer", __func__); 1049 1050 bzero(password, strlen(password)); 1051 bzero(crypted, strlen(crypted)); 1052 free(password); 1053 free(crypted); 1054 1055 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 1056 fatal("%s: BN_bin2bn (secret)", __func__); 1057 bzero(secret, secret_len); 1058 free(secret); 1059 1060 return ret; 1061 } 1062 1063 /* ARGSUSED */ 1064 void 1065 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 1066 { 1067 Authctxt *authctxt = ctxt; 1068 struct jpake_ctx *pctx = authctxt->methoddata; 1069 u_char *x3_proof, *x4_proof, *x2_s_proof; 1070 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 1071 char *crypt_scheme, *salt; 1072 1073 /* Disable this message */ 1074 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 1075 1076 if ((pctx->g_x3 = BN_new()) == NULL || 1077 (pctx->g_x4 = BN_new()) == NULL) 1078 fatal("%s: BN_new", __func__); 1079 1080 /* Fetch step 1 values */ 1081 crypt_scheme = packet_get_string(NULL); 1082 salt = packet_get_string(NULL); 1083 pctx->server_id = packet_get_string(&pctx->server_id_len); 1084 packet_get_bignum2(pctx->g_x3); 1085 packet_get_bignum2(pctx->g_x4); 1086 x3_proof = packet_get_string(&x3_proof_len); 1087 x4_proof = packet_get_string(&x4_proof_len); 1088 packet_check_eom(); 1089 1090 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1091 1092 /* Obtain password and derive secret */ 1093 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1094 bzero(crypt_scheme, strlen(crypt_scheme)); 1095 bzero(salt, strlen(salt)); 1096 free(crypt_scheme); 1097 free(salt); 1098 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1099 1100 /* Calculate step 2 values */ 1101 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1102 pctx->g_x3, pctx->g_x4, pctx->x2, 1103 pctx->server_id, pctx->server_id_len, 1104 pctx->client_id, pctx->client_id_len, 1105 x3_proof, x3_proof_len, 1106 x4_proof, x4_proof_len, 1107 &pctx->a, 1108 &x2_s_proof, &x2_s_proof_len); 1109 1110 bzero(x3_proof, x3_proof_len); 1111 bzero(x4_proof, x4_proof_len); 1112 free(x3_proof); 1113 free(x4_proof); 1114 1115 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1116 1117 /* Send values for step 2 */ 1118 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1119 packet_put_bignum2(pctx->a); 1120 packet_put_string(x2_s_proof, x2_s_proof_len); 1121 packet_send(); 1122 1123 bzero(x2_s_proof, x2_s_proof_len); 1124 free(x2_s_proof); 1125 1126 /* Expect step 2 packet from peer */ 1127 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1128 input_userauth_jpake_server_step2); 1129 } 1130 1131 /* ARGSUSED */ 1132 void 1133 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1134 { 1135 Authctxt *authctxt = ctxt; 1136 struct jpake_ctx *pctx = authctxt->methoddata; 1137 u_char *x4_s_proof; 1138 u_int x4_s_proof_len; 1139 1140 /* Disable this message */ 1141 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1142 1143 if ((pctx->b = BN_new()) == NULL) 1144 fatal("%s: BN_new", __func__); 1145 1146 /* Fetch step 2 values */ 1147 packet_get_bignum2(pctx->b); 1148 x4_s_proof = packet_get_string(&x4_s_proof_len); 1149 packet_check_eom(); 1150 1151 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1152 1153 /* Derive shared key and calculate confirmation hash */ 1154 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1155 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1156 pctx->client_id, pctx->client_id_len, 1157 pctx->server_id, pctx->server_id_len, 1158 session_id2, session_id2_len, 1159 x4_s_proof, x4_s_proof_len, 1160 &pctx->k, 1161 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1162 1163 bzero(x4_s_proof, x4_s_proof_len); 1164 free(x4_s_proof); 1165 1166 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1167 1168 /* Send key confirmation proof */ 1169 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1170 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1171 packet_send(); 1172 1173 /* Expect confirmation from peer */ 1174 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1175 input_userauth_jpake_server_confirm); 1176 } 1177 1178 /* ARGSUSED */ 1179 void 1180 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1181 { 1182 Authctxt *authctxt = ctxt; 1183 struct jpake_ctx *pctx = authctxt->methoddata; 1184 1185 /* Disable this message */ 1186 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1187 1188 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1189 packet_check_eom(); 1190 1191 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1192 1193 /* Verify expected confirmation hash */ 1194 if (jpake_check_confirm(pctx->k, 1195 pctx->server_id, pctx->server_id_len, 1196 session_id2, session_id2_len, 1197 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1198 debug("%s: %s success", __func__, authctxt->method->name); 1199 else { 1200 debug("%s: confirmation mismatch", __func__); 1201 /* XXX stash this so if auth succeeds then we can warn/kill */ 1202 } 1203 1204 userauth_jpake_cleanup(authctxt); 1205 } 1206 #endif /* JPAKE */ 1207 1208 static int 1209 identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1210 u_char *data, u_int datalen) 1211 { 1212 Key *prv; 1213 int ret; 1214 1215 /* the agent supports this key */ 1216 if (id->ac) 1217 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1218 data, datalen)); 1219 /* 1220 * we have already loaded the private key or 1221 * the private key is stored in external hardware 1222 */ 1223 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1224 return (key_sign(id->key, sigp, lenp, data, datalen)); 1225 /* load the private key from the file */ 1226 if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL) 1227 return (-1); 1228 ret = key_sign(prv, sigp, lenp, data, datalen); 1229 key_free(prv); 1230 return (ret); 1231 } 1232 1233 static int 1234 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1235 { 1236 Buffer b; 1237 u_char *blob, *signature; 1238 u_int bloblen, slen; 1239 u_int skip = 0; 1240 int ret = -1; 1241 int have_sig = 1; 1242 char *fp; 1243 1244 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1245 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1246 free(fp); 1247 1248 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1249 /* we cannot handle this key */ 1250 debug3("sign_and_send_pubkey: cannot handle key"); 1251 return 0; 1252 } 1253 /* data to be signed */ 1254 buffer_init(&b); 1255 if (datafellows & SSH_OLD_SESSIONID) { 1256 buffer_append(&b, session_id2, session_id2_len); 1257 skip = session_id2_len; 1258 } else { 1259 buffer_put_string(&b, session_id2, session_id2_len); 1260 skip = buffer_len(&b); 1261 } 1262 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1263 buffer_put_cstring(&b, authctxt->server_user); 1264 buffer_put_cstring(&b, 1265 datafellows & SSH_BUG_PKSERVICE ? 1266 "ssh-userauth" : 1267 authctxt->service); 1268 if (datafellows & SSH_BUG_PKAUTH) { 1269 buffer_put_char(&b, have_sig); 1270 } else { 1271 buffer_put_cstring(&b, authctxt->method->name); 1272 buffer_put_char(&b, have_sig); 1273 buffer_put_cstring(&b, key_ssh_name(id->key)); 1274 } 1275 buffer_put_string(&b, blob, bloblen); 1276 1277 /* generate signature */ 1278 ret = identity_sign(id, &signature, &slen, 1279 buffer_ptr(&b), buffer_len(&b)); 1280 if (ret == -1) { 1281 free(blob); 1282 buffer_free(&b); 1283 return 0; 1284 } 1285 #ifdef DEBUG_PK 1286 buffer_dump(&b); 1287 #endif 1288 if (datafellows & SSH_BUG_PKSERVICE) { 1289 buffer_clear(&b); 1290 buffer_append(&b, session_id2, session_id2_len); 1291 skip = session_id2_len; 1292 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1293 buffer_put_cstring(&b, authctxt->server_user); 1294 buffer_put_cstring(&b, authctxt->service); 1295 buffer_put_cstring(&b, authctxt->method->name); 1296 buffer_put_char(&b, have_sig); 1297 if (!(datafellows & SSH_BUG_PKAUTH)) 1298 buffer_put_cstring(&b, key_ssh_name(id->key)); 1299 buffer_put_string(&b, blob, bloblen); 1300 } 1301 free(blob); 1302 1303 /* append signature */ 1304 buffer_put_string(&b, signature, slen); 1305 free(signature); 1306 1307 /* skip session id and packet type */ 1308 if (buffer_len(&b) < skip + 1) 1309 fatal("userauth_pubkey: internal error"); 1310 buffer_consume(&b, skip + 1); 1311 1312 /* put remaining data from buffer into packet */ 1313 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1314 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1315 buffer_free(&b); 1316 packet_send(); 1317 1318 return 1; 1319 } 1320 1321 static int 1322 send_pubkey_test(Authctxt *authctxt, Identity *id) 1323 { 1324 u_char *blob; 1325 u_int bloblen, have_sig = 0; 1326 1327 debug3("send_pubkey_test"); 1328 1329 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1330 /* we cannot handle this key */ 1331 debug3("send_pubkey_test: cannot handle key"); 1332 return 0; 1333 } 1334 /* register callback for USERAUTH_PK_OK message */ 1335 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1336 1337 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1338 packet_put_cstring(authctxt->server_user); 1339 packet_put_cstring(authctxt->service); 1340 packet_put_cstring(authctxt->method->name); 1341 packet_put_char(have_sig); 1342 if (!(datafellows & SSH_BUG_PKAUTH)) 1343 packet_put_cstring(key_ssh_name(id->key)); 1344 packet_put_string(blob, bloblen); 1345 free(blob); 1346 packet_send(); 1347 return 1; 1348 } 1349 1350 static Key * 1351 load_identity_file(char *filename, int userprovided) 1352 { 1353 Key *private; 1354 char prompt[300], *passphrase; 1355 int perm_ok = 0, quit, i; 1356 struct stat st; 1357 1358 if (stat(filename, &st) < 0) { 1359 (userprovided ? logit : debug3)("no such identity: %s: %s", 1360 filename, strerror(errno)); 1361 return NULL; 1362 } 1363 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1364 if (!perm_ok) { 1365 if (private != NULL) 1366 key_free(private); 1367 return NULL; 1368 } 1369 if (private == NULL) { 1370 if (options.batch_mode) 1371 return NULL; 1372 snprintf(prompt, sizeof prompt, 1373 "Enter passphrase for key '%.100s': ", filename); 1374 for (i = 0; i < options.number_of_password_prompts; i++) { 1375 passphrase = read_passphrase(prompt, 0); 1376 if (strcmp(passphrase, "") != 0) { 1377 private = key_load_private_type(KEY_UNSPEC, 1378 filename, passphrase, NULL, NULL); 1379 quit = 0; 1380 } else { 1381 debug2("no passphrase given, try next key"); 1382 quit = 1; 1383 } 1384 memset(passphrase, 0, strlen(passphrase)); 1385 free(passphrase); 1386 if (private != NULL || quit) 1387 break; 1388 debug2("bad passphrase given, try again..."); 1389 } 1390 } 1391 return private; 1392 } 1393 1394 /* 1395 * try keys in the following order: 1396 * 1. agent keys that are found in the config file 1397 * 2. other agent keys 1398 * 3. keys that are only listed in the config file 1399 */ 1400 static void 1401 pubkey_prepare(Authctxt *authctxt) 1402 { 1403 Identity *id, *id2, *tmp; 1404 Idlist agent, files, *preferred; 1405 Key *key; 1406 AuthenticationConnection *ac; 1407 char *comment; 1408 int i, found; 1409 1410 TAILQ_INIT(&agent); /* keys from the agent */ 1411 TAILQ_INIT(&files); /* keys from the config file */ 1412 preferred = &authctxt->keys; 1413 TAILQ_INIT(preferred); /* preferred order of keys */ 1414 1415 /* list of keys stored in the filesystem and PKCS#11 */ 1416 for (i = 0; i < options.num_identity_files; i++) { 1417 key = options.identity_keys[i]; 1418 if (key && key->type == KEY_RSA1) 1419 continue; 1420 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1421 continue; 1422 options.identity_keys[i] = NULL; 1423 id = xcalloc(1, sizeof(*id)); 1424 id->key = key; 1425 id->filename = xstrdup(options.identity_files[i]); 1426 id->userprovided = options.identity_file_userprovided[i]; 1427 TAILQ_INSERT_TAIL(&files, id, next); 1428 } 1429 /* Prefer PKCS11 keys that are explicitly listed */ 1430 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1431 if (id->key == NULL || (id->key->flags & KEY_FLAG_EXT) == 0) 1432 continue; 1433 found = 0; 1434 TAILQ_FOREACH(id2, &files, next) { 1435 if (id2->key == NULL || 1436 (id2->key->flags & KEY_FLAG_EXT) != 0) 1437 continue; 1438 if (key_equal(id->key, id2->key)) { 1439 TAILQ_REMOVE(&files, id, next); 1440 TAILQ_INSERT_TAIL(preferred, id, next); 1441 found = 1; 1442 break; 1443 } 1444 } 1445 /* If IdentitiesOnly set and key not found then don't use it */ 1446 if (!found && options.identities_only) { 1447 TAILQ_REMOVE(&files, id, next); 1448 memset(id, 0, sizeof(*id)); 1449 free(id); 1450 } 1451 } 1452 /* list of keys supported by the agent */ 1453 if ((ac = ssh_get_authentication_connection())) { 1454 for (key = ssh_get_first_identity(ac, &comment, 2); 1455 key != NULL; 1456 key = ssh_get_next_identity(ac, &comment, 2)) { 1457 found = 0; 1458 TAILQ_FOREACH(id, &files, next) { 1459 /* agent keys from the config file are preferred */ 1460 if (key_equal(key, id->key)) { 1461 key_free(key); 1462 free(comment); 1463 TAILQ_REMOVE(&files, id, next); 1464 TAILQ_INSERT_TAIL(preferred, id, next); 1465 id->ac = ac; 1466 found = 1; 1467 break; 1468 } 1469 } 1470 if (!found && !options.identities_only) { 1471 id = xcalloc(1, sizeof(*id)); 1472 id->key = key; 1473 id->filename = comment; 1474 id->ac = ac; 1475 TAILQ_INSERT_TAIL(&agent, id, next); 1476 } 1477 } 1478 /* append remaining agent keys */ 1479 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1480 TAILQ_REMOVE(&agent, id, next); 1481 TAILQ_INSERT_TAIL(preferred, id, next); 1482 } 1483 authctxt->agent = ac; 1484 } 1485 /* append remaining keys from the config file */ 1486 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1487 TAILQ_REMOVE(&files, id, next); 1488 TAILQ_INSERT_TAIL(preferred, id, next); 1489 } 1490 TAILQ_FOREACH(id, preferred, next) { 1491 debug2("key: %s (%p),%s", id->filename, id->key, 1492 id->userprovided ? " explicit" : ""); 1493 } 1494 } 1495 1496 static void 1497 pubkey_cleanup(Authctxt *authctxt) 1498 { 1499 Identity *id; 1500 1501 if (authctxt->agent != NULL) 1502 ssh_close_authentication_connection(authctxt->agent); 1503 for (id = TAILQ_FIRST(&authctxt->keys); id; 1504 id = TAILQ_FIRST(&authctxt->keys)) { 1505 TAILQ_REMOVE(&authctxt->keys, id, next); 1506 if (id->key) 1507 key_free(id->key); 1508 free(id->filename); 1509 free(id); 1510 } 1511 } 1512 1513 int 1514 userauth_pubkey(Authctxt *authctxt) 1515 { 1516 Identity *id; 1517 int sent = 0; 1518 1519 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1520 if (id->tried++) 1521 return (0); 1522 /* move key to the end of the queue */ 1523 TAILQ_REMOVE(&authctxt->keys, id, next); 1524 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1525 /* 1526 * send a test message if we have the public key. for 1527 * encrypted keys we cannot do this and have to load the 1528 * private key instead 1529 */ 1530 if (id->key && id->key->type != KEY_RSA1) { 1531 debug("Offering %s public key: %s", key_type(id->key), 1532 id->filename); 1533 sent = send_pubkey_test(authctxt, id); 1534 } else if (id->key == NULL) { 1535 debug("Trying private key: %s", id->filename); 1536 id->key = load_identity_file(id->filename, 1537 id->userprovided); 1538 if (id->key != NULL) { 1539 id->isprivate = 1; 1540 sent = sign_and_send_pubkey(authctxt, id); 1541 key_free(id->key); 1542 id->key = NULL; 1543 } 1544 } 1545 if (sent) 1546 return (sent); 1547 } 1548 return (0); 1549 } 1550 1551 /* 1552 * Send userauth request message specifying keyboard-interactive method. 1553 */ 1554 int 1555 userauth_kbdint(Authctxt *authctxt) 1556 { 1557 static int attempt = 0; 1558 1559 if (attempt++ >= options.number_of_password_prompts) 1560 return 0; 1561 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1562 if (attempt > 1 && !authctxt->info_req_seen) { 1563 debug3("userauth_kbdint: disable: no info_req_seen"); 1564 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1565 return 0; 1566 } 1567 1568 debug2("userauth_kbdint"); 1569 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1570 packet_put_cstring(authctxt->server_user); 1571 packet_put_cstring(authctxt->service); 1572 packet_put_cstring(authctxt->method->name); 1573 packet_put_cstring(""); /* lang */ 1574 packet_put_cstring(options.kbd_interactive_devices ? 1575 options.kbd_interactive_devices : ""); 1576 packet_send(); 1577 1578 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1579 return 1; 1580 } 1581 1582 /* 1583 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1584 */ 1585 void 1586 input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1587 { 1588 Authctxt *authctxt = ctxt; 1589 char *name, *inst, *lang, *prompt, *response; 1590 u_int num_prompts, i; 1591 int echo = 0; 1592 1593 debug2("input_userauth_info_req"); 1594 1595 if (authctxt == NULL) 1596 fatal("input_userauth_info_req: no authentication context"); 1597 1598 authctxt->info_req_seen = 1; 1599 1600 name = packet_get_string(NULL); 1601 inst = packet_get_string(NULL); 1602 lang = packet_get_string(NULL); 1603 if (strlen(name) > 0) 1604 logit("%s", name); 1605 if (strlen(inst) > 0) 1606 logit("%s", inst); 1607 free(name); 1608 free(inst); 1609 free(lang); 1610 1611 num_prompts = packet_get_int(); 1612 /* 1613 * Begin to build info response packet based on prompts requested. 1614 * We commit to providing the correct number of responses, so if 1615 * further on we run into a problem that prevents this, we have to 1616 * be sure and clean this up and send a correct error response. 1617 */ 1618 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1619 packet_put_int(num_prompts); 1620 1621 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1622 for (i = 0; i < num_prompts; i++) { 1623 prompt = packet_get_string(NULL); 1624 echo = packet_get_char(); 1625 1626 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1627 1628 packet_put_cstring(response); 1629 memset(response, 0, strlen(response)); 1630 free(response); 1631 free(prompt); 1632 } 1633 packet_check_eom(); /* done with parsing incoming message. */ 1634 1635 packet_add_padding(64); 1636 packet_send(); 1637 } 1638 1639 static int 1640 ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1641 u_char *data, u_int datalen) 1642 { 1643 Buffer b; 1644 struct stat st; 1645 pid_t pid; 1646 int to[2], from[2], status, version = 2; 1647 1648 debug2("ssh_keysign called"); 1649 1650 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1651 error("ssh_keysign: not installed: %s", strerror(errno)); 1652 return -1; 1653 } 1654 if (fflush(stdout) != 0) 1655 error("ssh_keysign: fflush: %s", strerror(errno)); 1656 if (pipe(to) < 0) { 1657 error("ssh_keysign: pipe: %s", strerror(errno)); 1658 return -1; 1659 } 1660 if (pipe(from) < 0) { 1661 error("ssh_keysign: pipe: %s", strerror(errno)); 1662 return -1; 1663 } 1664 if ((pid = fork()) < 0) { 1665 error("ssh_keysign: fork: %s", strerror(errno)); 1666 return -1; 1667 } 1668 if (pid == 0) { 1669 /* keep the socket on exec */ 1670 fcntl(packet_get_connection_in(), F_SETFD, 0); 1671 permanently_drop_suid(getuid()); 1672 close(from[0]); 1673 if (dup2(from[1], STDOUT_FILENO) < 0) 1674 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1675 close(to[1]); 1676 if (dup2(to[0], STDIN_FILENO) < 0) 1677 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1678 close(from[1]); 1679 close(to[0]); 1680 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1681 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1682 strerror(errno)); 1683 } 1684 close(from[1]); 1685 close(to[0]); 1686 1687 buffer_init(&b); 1688 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1689 buffer_put_string(&b, data, datalen); 1690 if (ssh_msg_send(to[1], version, &b) == -1) 1691 fatal("ssh_keysign: couldn't send request"); 1692 1693 if (ssh_msg_recv(from[0], &b) < 0) { 1694 error("ssh_keysign: no reply"); 1695 buffer_free(&b); 1696 return -1; 1697 } 1698 close(from[0]); 1699 close(to[1]); 1700 1701 while (waitpid(pid, &status, 0) < 0) 1702 if (errno != EINTR) 1703 break; 1704 1705 if (buffer_get_char(&b) != version) { 1706 error("ssh_keysign: bad version"); 1707 buffer_free(&b); 1708 return -1; 1709 } 1710 *sigp = buffer_get_string(&b, lenp); 1711 buffer_free(&b); 1712 1713 return 0; 1714 } 1715 1716 int 1717 userauth_hostbased(Authctxt *authctxt) 1718 { 1719 Key *private = NULL; 1720 Sensitive *sensitive = authctxt->sensitive; 1721 Buffer b; 1722 u_char *signature, *blob; 1723 char *chost, *pkalg, *p; 1724 const char *service; 1725 u_int blen, slen; 1726 int ok, i, found = 0; 1727 1728 /* check for a useful key */ 1729 for (i = 0; i < sensitive->nkeys; i++) { 1730 private = sensitive->keys[i]; 1731 if (private && private->type != KEY_RSA1) { 1732 found = 1; 1733 /* we take and free the key */ 1734 sensitive->keys[i] = NULL; 1735 break; 1736 } 1737 } 1738 if (!found) { 1739 debug("No more client hostkeys for hostbased authentication."); 1740 return 0; 1741 } 1742 if (key_to_blob(private, &blob, &blen) == 0) { 1743 key_free(private); 1744 return 0; 1745 } 1746 /* figure out a name for the client host */ 1747 p = get_local_name(packet_get_connection_in()); 1748 if (p == NULL) { 1749 error("userauth_hostbased: cannot get local ipaddr/name"); 1750 key_free(private); 1751 free(blob); 1752 return 0; 1753 } 1754 xasprintf(&chost, "%s.", p); 1755 debug2("userauth_hostbased: chost %s", chost); 1756 free(p); 1757 1758 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1759 authctxt->service; 1760 pkalg = xstrdup(key_ssh_name(private)); 1761 buffer_init(&b); 1762 /* construct data */ 1763 buffer_put_string(&b, session_id2, session_id2_len); 1764 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1765 buffer_put_cstring(&b, authctxt->server_user); 1766 buffer_put_cstring(&b, service); 1767 buffer_put_cstring(&b, authctxt->method->name); 1768 buffer_put_cstring(&b, pkalg); 1769 buffer_put_string(&b, blob, blen); 1770 buffer_put_cstring(&b, chost); 1771 buffer_put_cstring(&b, authctxt->local_user); 1772 #ifdef DEBUG_PK 1773 buffer_dump(&b); 1774 #endif 1775 if (sensitive->external_keysign) 1776 ok = ssh_keysign(private, &signature, &slen, 1777 buffer_ptr(&b), buffer_len(&b)); 1778 else 1779 ok = key_sign(private, &signature, &slen, 1780 buffer_ptr(&b), buffer_len(&b)); 1781 key_free(private); 1782 buffer_free(&b); 1783 if (ok != 0) { 1784 error("key_sign failed"); 1785 free(chost); 1786 free(pkalg); 1787 free(blob); 1788 return 0; 1789 } 1790 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1791 packet_put_cstring(authctxt->server_user); 1792 packet_put_cstring(authctxt->service); 1793 packet_put_cstring(authctxt->method->name); 1794 packet_put_cstring(pkalg); 1795 packet_put_string(blob, blen); 1796 packet_put_cstring(chost); 1797 packet_put_cstring(authctxt->local_user); 1798 packet_put_string(signature, slen); 1799 memset(signature, 's', slen); 1800 free(signature); 1801 free(chost); 1802 free(pkalg); 1803 free(blob); 1804 1805 packet_send(); 1806 return 1; 1807 } 1808 1809 #ifdef JPAKE 1810 int 1811 userauth_jpake(Authctxt *authctxt) 1812 { 1813 struct jpake_ctx *pctx; 1814 u_char *x1_proof, *x2_proof; 1815 u_int x1_proof_len, x2_proof_len; 1816 static int attempt = 0; /* XXX share with userauth_password's? */ 1817 1818 if (attempt++ >= options.number_of_password_prompts) 1819 return 0; 1820 if (attempt != 1) 1821 error("Permission denied, please try again."); 1822 1823 if (authctxt->methoddata != NULL) 1824 fatal("%s: authctxt->methoddata already set (%p)", 1825 __func__, authctxt->methoddata); 1826 1827 authctxt->methoddata = pctx = jpake_new(); 1828 1829 /* 1830 * Send request immediately, to get the protocol going while 1831 * we do the initial computations. 1832 */ 1833 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1834 packet_put_cstring(authctxt->server_user); 1835 packet_put_cstring(authctxt->service); 1836 packet_put_cstring(authctxt->method->name); 1837 packet_send(); 1838 packet_write_wait(); 1839 1840 jpake_step1(pctx->grp, 1841 &pctx->client_id, &pctx->client_id_len, 1842 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1843 &x1_proof, &x1_proof_len, 1844 &x2_proof, &x2_proof_len); 1845 1846 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1847 1848 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1849 packet_put_string(pctx->client_id, pctx->client_id_len); 1850 packet_put_bignum2(pctx->g_x1); 1851 packet_put_bignum2(pctx->g_x2); 1852 packet_put_string(x1_proof, x1_proof_len); 1853 packet_put_string(x2_proof, x2_proof_len); 1854 packet_send(); 1855 1856 bzero(x1_proof, x1_proof_len); 1857 bzero(x2_proof, x2_proof_len); 1858 free(x1_proof); 1859 free(x2_proof); 1860 1861 /* Expect step 1 packet from peer */ 1862 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1863 input_userauth_jpake_server_step1); 1864 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1865 &input_userauth_success_unexpected); 1866 1867 return 1; 1868 } 1869 1870 void 1871 userauth_jpake_cleanup(Authctxt *authctxt) 1872 { 1873 debug3("%s: clean up", __func__); 1874 if (authctxt->methoddata != NULL) { 1875 jpake_free(authctxt->methoddata); 1876 authctxt->methoddata = NULL; 1877 } 1878 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1879 } 1880 #endif /* JPAKE */ 1881 1882 #if KRB5 1883 static int 1884 ssh_krb5_helper(krb5_data *ap) 1885 { 1886 krb5_context xcontext = NULL; /* XXX share with ssh1 */ 1887 krb5_auth_context xauth_context = NULL; 1888 1889 krb5_context *context; 1890 krb5_auth_context *auth_context; 1891 krb5_error_code problem; 1892 const char *tkfile; 1893 struct stat buf; 1894 krb5_ccache ccache = NULL; 1895 const char *remotehost; 1896 int ret; 1897 const char *errtxt; 1898 1899 memset(ap, 0, sizeof(*ap)); 1900 1901 context = &xcontext; 1902 auth_context = &xauth_context; 1903 1904 problem = krb5_init_context(context); 1905 if (problem) { 1906 debug("Kerberos v5: krb5_init_context failed"); 1907 ret = 0; 1908 goto out; 1909 } 1910 1911 tkfile = krb5_cc_default_name(*context); 1912 if (strncmp(tkfile, "FILE:", 5) == 0) 1913 tkfile += 5; 1914 1915 if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) { 1916 debug("Kerberos v5: could not get default ccache (permission denied)."); 1917 ret = 0; 1918 goto out; 1919 } 1920 1921 problem = krb5_cc_default(*context, &ccache); 1922 if (problem) { 1923 errtxt = krb5_get_error_message(*context, problem); 1924 if (errtxt != NULL) { 1925 debug("Kerberos v5: krb5_cc_default failed: %s", 1926 errtxt); 1927 krb5_free_error_message(*context, errtxt); 1928 } else 1929 debug("Kerberos v5: krb5_cc_default failed: %d", 1930 problem); 1931 ret = 0; 1932 goto out; 1933 } 1934 1935 remotehost = get_canonical_hostname(1); 1936 1937 problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED, 1938 "host", remotehost, NULL, ccache, ap); 1939 if (problem) { 1940 errtxt = krb5_get_error_message(*context, problem); 1941 if (errtxt != NULL) { 1942 debug("Kerberos v5: krb5_mk_req failed: %s", errtxt); 1943 krb5_free_error_message(*context, errtxt); 1944 } else 1945 debug("Kerberos v5: krb5_mk_req failed: %d", problem); 1946 ret = 0; 1947 goto out; 1948 } 1949 ret = 1; 1950 1951 out: 1952 if (ccache != NULL) 1953 krb5_cc_close(*context, ccache); 1954 if (*auth_context) 1955 krb5_auth_con_free(*context, *auth_context); 1956 if (*context) 1957 krb5_free_context(*context); 1958 return (ret); 1959 } 1960 1961 int 1962 userauth_kerberos(Authctxt *authctxt) 1963 { 1964 krb5_data ap; 1965 1966 if (ssh_krb5_helper(&ap) == 0) 1967 return (0); 1968 1969 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1970 packet_put_cstring(authctxt->server_user); 1971 packet_put_cstring(authctxt->service); 1972 packet_put_cstring(authctxt->method->name); 1973 packet_put_string(ap.data, ap.length); 1974 packet_send(); 1975 1976 krb5_data_free(&ap); 1977 return (1); 1978 } 1979 #endif 1980 1981 /* find auth method */ 1982 1983 /* 1984 * given auth method name, if configurable options permit this method fill 1985 * in auth_ident field and return true, otherwise return false. 1986 */ 1987 static int 1988 authmethod_is_enabled(Authmethod *method) 1989 { 1990 if (method == NULL) 1991 return 0; 1992 /* return false if options indicate this method is disabled */ 1993 if (method->enabled == NULL || *method->enabled == 0) 1994 return 0; 1995 /* return false if batch mode is enabled but method needs interactive mode */ 1996 if (method->batch_flag != NULL && *method->batch_flag != 0) 1997 return 0; 1998 return 1; 1999 } 2000 2001 static Authmethod * 2002 authmethod_lookup(const char *name) 2003 { 2004 Authmethod *method = NULL; 2005 if (name != NULL) 2006 for (method = authmethods; method->name != NULL; method++) 2007 if (strcmp(name, method->name) == 0) 2008 return method; 2009 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 2010 return NULL; 2011 } 2012 2013 /* XXX internal state */ 2014 static Authmethod *current = NULL; 2015 static char *supported = NULL; 2016 static char *preferred = NULL; 2017 2018 /* 2019 * Given the authentication method list sent by the server, return the 2020 * next method we should try. If the server initially sends a nil list, 2021 * use a built-in default list. 2022 */ 2023 static Authmethod * 2024 authmethod_get(char *authlist) 2025 { 2026 char *name = NULL; 2027 u_int next; 2028 2029 /* Use a suitable default if we're passed a nil list. */ 2030 if (authlist == NULL || strlen(authlist) == 0) 2031 authlist = options.preferred_authentications; 2032 2033 if (supported == NULL || strcmp(authlist, supported) != 0) { 2034 debug3("start over, passed a different list %s", authlist); 2035 free(supported); 2036 supported = xstrdup(authlist); 2037 preferred = options.preferred_authentications; 2038 debug3("preferred %s", preferred); 2039 current = NULL; 2040 } else if (current != NULL && authmethod_is_enabled(current)) 2041 return current; 2042 2043 for (;;) { 2044 if ((name = match_list(preferred, supported, &next)) == NULL) { 2045 debug("No more authentication methods to try."); 2046 current = NULL; 2047 return NULL; 2048 } 2049 preferred += next; 2050 debug3("authmethod_lookup %s", name); 2051 debug3("remaining preferred: %s", preferred); 2052 if ((current = authmethod_lookup(name)) != NULL && 2053 authmethod_is_enabled(current)) { 2054 debug3("authmethod_is_enabled %s", name); 2055 debug("Next authentication method: %s", name); 2056 free(name); 2057 return current; 2058 } 2059 free(name); 2060 } 2061 } 2062 2063 static char * 2064 authmethods_get(void) 2065 { 2066 Authmethod *method = NULL; 2067 Buffer b; 2068 char *list; 2069 2070 buffer_init(&b); 2071 for (method = authmethods; method->name != NULL; method++) { 2072 if (authmethod_is_enabled(method)) { 2073 if (buffer_len(&b) > 0) 2074 buffer_append(&b, ",", 1); 2075 buffer_append(&b, method->name, strlen(method->name)); 2076 } 2077 } 2078 buffer_append(&b, "\0", 1); 2079 list = xstrdup(buffer_ptr(&b)); 2080 buffer_free(&b); 2081 return list; 2082 } 2083 2084