sshconnect2.c revision 294693
1/* $OpenBSD: sshconnect2.c,v 1.204 2014/02/02 03:44:32 djm Exp $ */ 2/* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include "includes.h" 28 29#include <sys/types.h> 30#include <sys/socket.h> 31#include <sys/wait.h> 32#include <sys/stat.h> 33 34#include <errno.h> 35#include <fcntl.h> 36#include <netdb.h> 37#include <pwd.h> 38#include <signal.h> 39#include <stdarg.h> 40#include <stdio.h> 41#include <string.h> 42#include <unistd.h> 43#if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !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 74#ifdef GSSAPI 75#include "ssh-gss.h" 76#endif 77 78/* import */ 79extern char *client_version_string; 80extern char *server_version_string; 81extern Options options; 82 83/* 84 * SSH2 key exchange 85 */ 86 87u_char *session_id2 = NULL; 88u_int session_id2_len = 0; 89 90char *xxx_host; 91struct sockaddr *xxx_hostaddr; 92 93Kex *xxx_kex = NULL; 94 95static int 96verify_host_key_callback(Key *hostkey) 97{ 98 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 99 fatal("Host key verification failed."); 100 return 0; 101} 102 103static char * 104order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 105{ 106 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 107 size_t maxlen; 108 struct hostkeys *hostkeys; 109 int ktype; 110 u_int i; 111 112 /* Find all hostkeys for this hostname */ 113 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 114 hostkeys = init_hostkeys(); 115 for (i = 0; i < options.num_user_hostfiles; i++) 116 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 117 for (i = 0; i < options.num_system_hostfiles; i++) 118 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 119 120 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 121 maxlen = strlen(avail) + 1; 122 first = xmalloc(maxlen); 123 last = xmalloc(maxlen); 124 *first = *last = '\0'; 125 126#define ALG_APPEND(to, from) \ 127 do { \ 128 if (*to != '\0') \ 129 strlcat(to, ",", maxlen); \ 130 strlcat(to, from, maxlen); \ 131 } while (0) 132 133 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 134 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) 135 fatal("%s: unknown alg %s", __func__, alg); 136 if (lookup_key_in_hostkeys_by_type(hostkeys, 137 key_type_plain(ktype), NULL)) 138 ALG_APPEND(first, alg); 139 else 140 ALG_APPEND(last, alg); 141 } 142#undef ALG_APPEND 143 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); 144 if (*first != '\0') 145 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 146 147 free(first); 148 free(last); 149 free(hostname); 150 free(oavail); 151 free_hostkeys(hostkeys); 152 153 return ret; 154} 155 156void 157ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 158{ 159 Kex *kex; 160 161 xxx_host = host; 162 xxx_hostaddr = hostaddr; 163 164 if (options.ciphers == (char *)-1) { 165 logit("No valid ciphers for protocol version 2 given, using defaults."); 166 options.ciphers = NULL; 167 } 168 if (options.ciphers != NULL) { 169 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 170 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 171 } 172 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 173 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 174 myproposal[PROPOSAL_ENC_ALGS_STOC] = 175 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 176 if (options.compression) { 177 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 178 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 179 } else { 180 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 181 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 182 } 183 if (options.macs != NULL) { 184 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 185 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 186 } 187 if (options.hostkeyalgorithms != NULL) 188 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 189 compat_pkalg_proposal(options.hostkeyalgorithms); 190 else { 191 /* Prefer algorithms that we already have keys for */ 192 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 193 compat_pkalg_proposal( 194 order_hostkeyalgs(host, hostaddr, port)); 195 } 196 if (options.kex_algorithms != NULL) 197 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 198 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 199 myproposal[PROPOSAL_KEX_ALGS]); 200 201 if (options.rekey_limit || options.rekey_interval) 202 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 203 (time_t)options.rekey_interval); 204 205 /* start key exchange */ 206 kex = kex_setup(myproposal); 207 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 208 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 209 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 210 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 211 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 212 kex->kex[KEX_C25519_SHA256] = kexc25519_client; 213 kex->client_version_string=client_version_string; 214 kex->server_version_string=server_version_string; 215 kex->verify_host_key=&verify_host_key_callback; 216 217 xxx_kex = kex; 218 219 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 220 221 if (options.use_roaming && !kex->roaming) { 222 debug("Roaming not allowed by server"); 223 options.use_roaming = 0; 224 } 225 226 session_id2 = kex->session_id; 227 session_id2_len = kex->session_id_len; 228 229#ifdef DEBUG_KEXDH 230 /* send 1st encrypted/maced/compressed message */ 231 packet_start(SSH2_MSG_IGNORE); 232 packet_put_cstring("markus"); 233 packet_send(); 234 packet_write_wait(); 235#endif 236} 237 238/* 239 * Authenticate user 240 */ 241 242typedef struct Authctxt Authctxt; 243typedef struct Authmethod Authmethod; 244typedef struct identity Identity; 245typedef struct idlist Idlist; 246 247struct identity { 248 TAILQ_ENTRY(identity) next; 249 AuthenticationConnection *ac; /* set if agent supports key */ 250 Key *key; /* public/private key */ 251 char *filename; /* comment for agent-only keys */ 252 int tried; 253 int isprivate; /* key points to the private key */ 254 int userprovided; 255}; 256TAILQ_HEAD(idlist, identity); 257 258struct Authctxt { 259 const char *server_user; 260 const char *local_user; 261 const char *host; 262 const char *service; 263 Authmethod *method; 264 sig_atomic_t success; 265 char *authlist; 266 /* pubkey */ 267 Idlist keys; 268 AuthenticationConnection *agent; 269 /* hostbased */ 270 Sensitive *sensitive; 271 /* kbd-interactive */ 272 int info_req_seen; 273 /* generic */ 274 void *methoddata; 275}; 276struct Authmethod { 277 char *name; /* string to compare against server's list */ 278 int (*userauth)(Authctxt *authctxt); 279 void (*cleanup)(Authctxt *authctxt); 280 int *enabled; /* flag in option struct that enables method */ 281 int *batch_flag; /* flag in option struct that disables method */ 282}; 283 284void input_userauth_success(int, u_int32_t, void *); 285void input_userauth_success_unexpected(int, u_int32_t, void *); 286void input_userauth_failure(int, u_int32_t, void *); 287void input_userauth_banner(int, u_int32_t, void *); 288void input_userauth_error(int, u_int32_t, void *); 289void input_userauth_info_req(int, u_int32_t, void *); 290void input_userauth_pk_ok(int, u_int32_t, void *); 291void input_userauth_passwd_changereq(int, u_int32_t, void *); 292 293int userauth_none(Authctxt *); 294int userauth_pubkey(Authctxt *); 295int userauth_passwd(Authctxt *); 296int userauth_kbdint(Authctxt *); 297int userauth_hostbased(Authctxt *); 298 299#ifdef GSSAPI 300int userauth_gssapi(Authctxt *authctxt); 301void input_gssapi_response(int type, u_int32_t, void *); 302void input_gssapi_token(int type, u_int32_t, void *); 303void input_gssapi_hash(int type, u_int32_t, void *); 304void input_gssapi_error(int, u_int32_t, void *); 305void input_gssapi_errtok(int, u_int32_t, void *); 306#endif 307 308void userauth(Authctxt *, char *); 309 310static int sign_and_send_pubkey(Authctxt *, Identity *); 311static void pubkey_prepare(Authctxt *); 312static void pubkey_cleanup(Authctxt *); 313static Key *load_identity_file(char *, int); 314 315static Authmethod *authmethod_get(char *authlist); 316static Authmethod *authmethod_lookup(const char *name); 317static char *authmethods_get(void); 318 319Authmethod authmethods[] = { 320#ifdef GSSAPI 321 {"gssapi-with-mic", 322 userauth_gssapi, 323 NULL, 324 &options.gss_authentication, 325 NULL}, 326#endif 327 {"hostbased", 328 userauth_hostbased, 329 NULL, 330 &options.hostbased_authentication, 331 NULL}, 332 {"publickey", 333 userauth_pubkey, 334 NULL, 335 &options.pubkey_authentication, 336 NULL}, 337 {"keyboard-interactive", 338 userauth_kbdint, 339 NULL, 340 &options.kbd_interactive_authentication, 341 &options.batch_mode}, 342 {"password", 343 userauth_passwd, 344 NULL, 345 &options.password_authentication, 346 &options.batch_mode}, 347 {"none", 348 userauth_none, 349 NULL, 350 NULL, 351 NULL}, 352 {NULL, NULL, NULL, NULL, NULL} 353}; 354 355void 356ssh_userauth2(const char *local_user, const char *server_user, char *host, 357 Sensitive *sensitive) 358{ 359 Authctxt authctxt; 360 int type; 361 362 if (options.challenge_response_authentication) 363 options.kbd_interactive_authentication = 1; 364 365 packet_start(SSH2_MSG_SERVICE_REQUEST); 366 packet_put_cstring("ssh-userauth"); 367 packet_send(); 368 debug("SSH2_MSG_SERVICE_REQUEST sent"); 369 packet_write_wait(); 370 type = packet_read(); 371 if (type != SSH2_MSG_SERVICE_ACCEPT) 372 fatal("Server denied authentication request: %d", type); 373 if (packet_remaining() > 0) { 374 char *reply = packet_get_string(NULL); 375 debug2("service_accept: %s", reply); 376 free(reply); 377 } else { 378 debug2("buggy server: service_accept w/o service"); 379 } 380 packet_check_eom(); 381 debug("SSH2_MSG_SERVICE_ACCEPT received"); 382 383 if (options.preferred_authentications == NULL) 384 options.preferred_authentications = authmethods_get(); 385 386 /* setup authentication context */ 387 memset(&authctxt, 0, sizeof(authctxt)); 388 pubkey_prepare(&authctxt); 389 authctxt.server_user = server_user; 390 authctxt.local_user = local_user; 391 authctxt.host = host; 392 authctxt.service = "ssh-connection"; /* service name */ 393 authctxt.success = 0; 394 authctxt.method = authmethod_lookup("none"); 395 authctxt.authlist = NULL; 396 authctxt.methoddata = NULL; 397 authctxt.sensitive = sensitive; 398 authctxt.info_req_seen = 0; 399 if (authctxt.method == NULL) 400 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 401 402 /* initial userauth request */ 403 userauth_none(&authctxt); 404 405 dispatch_init(&input_userauth_error); 406 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 407 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 408 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 409 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 410 411 pubkey_cleanup(&authctxt); 412 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 413 414 debug("Authentication succeeded (%s).", authctxt.method->name); 415} 416 417void 418userauth(Authctxt *authctxt, char *authlist) 419{ 420 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 421 authctxt->method->cleanup(authctxt); 422 423 free(authctxt->methoddata); 424 authctxt->methoddata = NULL; 425 if (authlist == NULL) { 426 authlist = authctxt->authlist; 427 } else { 428 free(authctxt->authlist); 429 authctxt->authlist = authlist; 430 } 431 for (;;) { 432 Authmethod *method = authmethod_get(authlist); 433 if (method == NULL) 434 fatal("Permission denied (%s).", authlist); 435 authctxt->method = method; 436 437 /* reset the per method handler */ 438 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 439 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 440 441 /* and try new method */ 442 if (method->userauth(authctxt) != 0) { 443 debug2("we sent a %s packet, wait for reply", method->name); 444 break; 445 } else { 446 debug2("we did not send a packet, disable method"); 447 method->enabled = NULL; 448 } 449 } 450} 451 452/* ARGSUSED */ 453void 454input_userauth_error(int type, u_int32_t seq, void *ctxt) 455{ 456 fatal("input_userauth_error: bad message during authentication: " 457 "type %d", type); 458} 459 460/* ARGSUSED */ 461void 462input_userauth_banner(int type, u_int32_t seq, void *ctxt) 463{ 464 char *msg, *raw, *lang; 465 u_int len; 466 467 debug3("input_userauth_banner"); 468 raw = packet_get_string(&len); 469 lang = packet_get_string(NULL); 470 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 471 if (len > 65536) 472 len = 65536; 473 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 474 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 475 fprintf(stderr, "%s", msg); 476 free(msg); 477 } 478 free(raw); 479 free(lang); 480} 481 482/* ARGSUSED */ 483void 484input_userauth_success(int type, u_int32_t seq, void *ctxt) 485{ 486 Authctxt *authctxt = ctxt; 487 488 if (authctxt == NULL) 489 fatal("input_userauth_success: no authentication context"); 490 free(authctxt->authlist); 491 authctxt->authlist = NULL; 492 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 493 authctxt->method->cleanup(authctxt); 494 free(authctxt->methoddata); 495 authctxt->methoddata = NULL; 496 authctxt->success = 1; /* break out */ 497} 498 499void 500input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 501{ 502 Authctxt *authctxt = ctxt; 503 504 if (authctxt == NULL) 505 fatal("%s: no authentication context", __func__); 506 507 fatal("Unexpected authentication success during %s.", 508 authctxt->method->name); 509} 510 511/* ARGSUSED */ 512void 513input_userauth_failure(int type, u_int32_t seq, void *ctxt) 514{ 515 Authctxt *authctxt = ctxt; 516 char *authlist = NULL; 517 int partial; 518 519 if (authctxt == NULL) 520 fatal("input_userauth_failure: no authentication context"); 521 522 authlist = packet_get_string(NULL); 523 partial = packet_get_char(); 524 packet_check_eom(); 525 526 if (partial != 0) { 527 logit("Authenticated with partial success."); 528 /* reset state */ 529 pubkey_cleanup(authctxt); 530 pubkey_prepare(authctxt); 531 } 532 debug("Authentications that can continue: %s", authlist); 533 534 userauth(authctxt, authlist); 535} 536 537/* ARGSUSED */ 538void 539input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 540{ 541 Authctxt *authctxt = ctxt; 542 Key *key = NULL; 543 Identity *id = NULL; 544 Buffer b; 545 int pktype, sent = 0; 546 u_int alen, blen; 547 char *pkalg, *fp; 548 u_char *pkblob; 549 550 if (authctxt == NULL) 551 fatal("input_userauth_pk_ok: no authentication context"); 552 if (datafellows & SSH_BUG_PKOK) { 553 /* this is similar to SSH_BUG_PKAUTH */ 554 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 555 pkblob = packet_get_string(&blen); 556 buffer_init(&b); 557 buffer_append(&b, pkblob, blen); 558 pkalg = buffer_get_string(&b, &alen); 559 buffer_free(&b); 560 } else { 561 pkalg = packet_get_string(&alen); 562 pkblob = packet_get_string(&blen); 563 } 564 packet_check_eom(); 565 566 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 567 568 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 569 debug("unknown pkalg %s", pkalg); 570 goto done; 571 } 572 if ((key = key_from_blob(pkblob, blen)) == NULL) { 573 debug("no key from blob. pkalg %s", pkalg); 574 goto done; 575 } 576 if (key->type != pktype) { 577 error("input_userauth_pk_ok: type mismatch " 578 "for decoded key (received %d, expected %d)", 579 key->type, pktype); 580 goto done; 581 } 582 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 583 debug2("input_userauth_pk_ok: fp %s", fp); 584 free(fp); 585 586 /* 587 * search keys in the reverse order, because last candidate has been 588 * moved to the end of the queue. this also avoids confusion by 589 * duplicate keys 590 */ 591 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 592 if (key_equal(key, id->key)) { 593 sent = sign_and_send_pubkey(authctxt, id); 594 break; 595 } 596 } 597done: 598 if (key != NULL) 599 key_free(key); 600 free(pkalg); 601 free(pkblob); 602 603 /* try another method if we did not send a packet */ 604 if (sent == 0) 605 userauth(authctxt, NULL); 606} 607 608#ifdef GSSAPI 609int 610userauth_gssapi(Authctxt *authctxt) 611{ 612 Gssctxt *gssctxt = NULL; 613 static gss_OID_set gss_supported = NULL; 614 static u_int mech = 0; 615 OM_uint32 min; 616 int ok = 0; 617 618 /* Try one GSSAPI method at a time, rather than sending them all at 619 * once. */ 620 621 if (gss_supported == NULL) 622 gss_indicate_mechs(&min, &gss_supported); 623 624 /* Check to see if the mechanism is usable before we offer it */ 625 while (mech < gss_supported->count && !ok) { 626 /* My DER encoding requires length<128 */ 627 if (gss_supported->elements[mech].length < 128 && 628 ssh_gssapi_check_mechanism(&gssctxt, 629 &gss_supported->elements[mech], authctxt->host)) { 630 ok = 1; /* Mechanism works */ 631 } else { 632 mech++; 633 } 634 } 635 636 if (!ok) 637 return 0; 638 639 authctxt->methoddata=(void *)gssctxt; 640 641 packet_start(SSH2_MSG_USERAUTH_REQUEST); 642 packet_put_cstring(authctxt->server_user); 643 packet_put_cstring(authctxt->service); 644 packet_put_cstring(authctxt->method->name); 645 646 packet_put_int(1); 647 648 packet_put_int((gss_supported->elements[mech].length) + 2); 649 packet_put_char(SSH_GSS_OIDTYPE); 650 packet_put_char(gss_supported->elements[mech].length); 651 packet_put_raw(gss_supported->elements[mech].elements, 652 gss_supported->elements[mech].length); 653 654 packet_send(); 655 656 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 657 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 658 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 659 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 660 661 mech++; /* Move along to next candidate */ 662 663 return 1; 664} 665 666static OM_uint32 667process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 668{ 669 Authctxt *authctxt = ctxt; 670 Gssctxt *gssctxt = authctxt->methoddata; 671 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 672 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 673 gss_buffer_desc gssbuf; 674 OM_uint32 status, ms, flags; 675 Buffer b; 676 677 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 678 recv_tok, &send_tok, &flags); 679 680 if (send_tok.length > 0) { 681 if (GSS_ERROR(status)) 682 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 683 else 684 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 685 686 packet_put_string(send_tok.value, send_tok.length); 687 packet_send(); 688 gss_release_buffer(&ms, &send_tok); 689 } 690 691 if (status == GSS_S_COMPLETE) { 692 /* send either complete or MIC, depending on mechanism */ 693 if (!(flags & GSS_C_INTEG_FLAG)) { 694 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 695 packet_send(); 696 } else { 697 ssh_gssapi_buildmic(&b, authctxt->server_user, 698 authctxt->service, "gssapi-with-mic"); 699 700 gssbuf.value = buffer_ptr(&b); 701 gssbuf.length = buffer_len(&b); 702 703 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 704 705 if (!GSS_ERROR(status)) { 706 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 707 packet_put_string(mic.value, mic.length); 708 709 packet_send(); 710 } 711 712 buffer_free(&b); 713 gss_release_buffer(&ms, &mic); 714 } 715 } 716 717 return status; 718} 719 720/* ARGSUSED */ 721void 722input_gssapi_response(int type, u_int32_t plen, void *ctxt) 723{ 724 Authctxt *authctxt = ctxt; 725 Gssctxt *gssctxt; 726 int oidlen; 727 char *oidv; 728 729 if (authctxt == NULL) 730 fatal("input_gssapi_response: no authentication context"); 731 gssctxt = authctxt->methoddata; 732 733 /* Setup our OID */ 734 oidv = packet_get_string(&oidlen); 735 736 if (oidlen <= 2 || 737 oidv[0] != SSH_GSS_OIDTYPE || 738 oidv[1] != oidlen - 2) { 739 free(oidv); 740 debug("Badly encoded mechanism OID received"); 741 userauth(authctxt, NULL); 742 return; 743 } 744 745 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 746 fatal("Server returned different OID than expected"); 747 748 packet_check_eom(); 749 750 free(oidv); 751 752 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 753 /* Start again with next method on list */ 754 debug("Trying to start again"); 755 userauth(authctxt, NULL); 756 return; 757 } 758} 759 760/* ARGSUSED */ 761void 762input_gssapi_token(int type, u_int32_t plen, void *ctxt) 763{ 764 Authctxt *authctxt = ctxt; 765 gss_buffer_desc recv_tok; 766 OM_uint32 status; 767 u_int slen; 768 769 if (authctxt == NULL) 770 fatal("input_gssapi_response: no authentication context"); 771 772 recv_tok.value = packet_get_string(&slen); 773 recv_tok.length = slen; /* safe typecast */ 774 775 packet_check_eom(); 776 777 status = process_gssapi_token(ctxt, &recv_tok); 778 779 free(recv_tok.value); 780 781 if (GSS_ERROR(status)) { 782 /* Start again with the next method in the list */ 783 userauth(authctxt, NULL); 784 return; 785 } 786} 787 788/* ARGSUSED */ 789void 790input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 791{ 792 Authctxt *authctxt = ctxt; 793 Gssctxt *gssctxt; 794 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 795 gss_buffer_desc recv_tok; 796 OM_uint32 ms; 797 u_int len; 798 799 if (authctxt == NULL) 800 fatal("input_gssapi_response: no authentication context"); 801 gssctxt = authctxt->methoddata; 802 803 recv_tok.value = packet_get_string(&len); 804 recv_tok.length = len; 805 806 packet_check_eom(); 807 808 /* Stick it into GSSAPI and see what it says */ 809 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 810 &recv_tok, &send_tok, NULL); 811 812 free(recv_tok.value); 813 gss_release_buffer(&ms, &send_tok); 814 815 /* Server will be returning a failed packet after this one */ 816} 817 818/* ARGSUSED */ 819void 820input_gssapi_error(int type, u_int32_t plen, void *ctxt) 821{ 822 char *msg; 823 char *lang; 824 825 /* maj */(void)packet_get_int(); 826 /* min */(void)packet_get_int(); 827 msg=packet_get_string(NULL); 828 lang=packet_get_string(NULL); 829 830 packet_check_eom(); 831 832 debug("Server GSSAPI Error:\n%s", msg); 833 free(msg); 834 free(lang); 835} 836#endif /* GSSAPI */ 837 838int 839userauth_none(Authctxt *authctxt) 840{ 841 /* initial userauth request */ 842 packet_start(SSH2_MSG_USERAUTH_REQUEST); 843 packet_put_cstring(authctxt->server_user); 844 packet_put_cstring(authctxt->service); 845 packet_put_cstring(authctxt->method->name); 846 packet_send(); 847 return 1; 848} 849 850int 851userauth_passwd(Authctxt *authctxt) 852{ 853 static int attempt = 0; 854 char prompt[150]; 855 char *password; 856 const char *host = options.host_key_alias ? options.host_key_alias : 857 authctxt->host; 858 859 if (attempt++ >= options.number_of_password_prompts) 860 return 0; 861 862 if (attempt != 1) 863 error("Permission denied, please try again."); 864 865 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 866 authctxt->server_user, host); 867 password = read_passphrase(prompt, 0); 868 packet_start(SSH2_MSG_USERAUTH_REQUEST); 869 packet_put_cstring(authctxt->server_user); 870 packet_put_cstring(authctxt->service); 871 packet_put_cstring(authctxt->method->name); 872 packet_put_char(0); 873 packet_put_cstring(password); 874 explicit_bzero(password, strlen(password)); 875 free(password); 876 packet_add_padding(64); 877 packet_send(); 878 879 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 880 &input_userauth_passwd_changereq); 881 882 return 1; 883} 884 885/* 886 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 887 */ 888/* ARGSUSED */ 889void 890input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 891{ 892 Authctxt *authctxt = ctxt; 893 char *info, *lang, *password = NULL, *retype = NULL; 894 char prompt[150]; 895 const char *host = options.host_key_alias ? options.host_key_alias : 896 authctxt->host; 897 898 debug2("input_userauth_passwd_changereq"); 899 900 if (authctxt == NULL) 901 fatal("input_userauth_passwd_changereq: " 902 "no authentication context"); 903 904 info = packet_get_string(NULL); 905 lang = packet_get_string(NULL); 906 if (strlen(info) > 0) 907 logit("%s", info); 908 free(info); 909 free(lang); 910 packet_start(SSH2_MSG_USERAUTH_REQUEST); 911 packet_put_cstring(authctxt->server_user); 912 packet_put_cstring(authctxt->service); 913 packet_put_cstring(authctxt->method->name); 914 packet_put_char(1); /* additional info */ 915 snprintf(prompt, sizeof(prompt), 916 "Enter %.30s@%.128s's old password: ", 917 authctxt->server_user, host); 918 password = read_passphrase(prompt, 0); 919 packet_put_cstring(password); 920 explicit_bzero(password, strlen(password)); 921 free(password); 922 password = NULL; 923 while (password == NULL) { 924 snprintf(prompt, sizeof(prompt), 925 "Enter %.30s@%.128s's new password: ", 926 authctxt->server_user, host); 927 password = read_passphrase(prompt, RP_ALLOW_EOF); 928 if (password == NULL) { 929 /* bail out */ 930 return; 931 } 932 snprintf(prompt, sizeof(prompt), 933 "Retype %.30s@%.128s's new password: ", 934 authctxt->server_user, host); 935 retype = read_passphrase(prompt, 0); 936 if (strcmp(password, retype) != 0) { 937 explicit_bzero(password, strlen(password)); 938 free(password); 939 logit("Mismatch; try again, EOF to quit."); 940 password = NULL; 941 } 942 explicit_bzero(retype, strlen(retype)); 943 free(retype); 944 } 945 packet_put_cstring(password); 946 explicit_bzero(password, strlen(password)); 947 free(password); 948 packet_add_padding(64); 949 packet_send(); 950 951 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 952 &input_userauth_passwd_changereq); 953} 954 955static int 956identity_sign(Identity *id, u_char **sigp, u_int *lenp, 957 u_char *data, u_int datalen) 958{ 959 Key *prv; 960 int ret; 961 962 /* the agent supports this key */ 963 if (id->ac) 964 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 965 data, datalen)); 966 /* 967 * we have already loaded the private key or 968 * the private key is stored in external hardware 969 */ 970 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 971 return (key_sign(id->key, sigp, lenp, data, datalen)); 972 /* load the private key from the file */ 973 if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL) 974 return (-1); 975 ret = key_sign(prv, sigp, lenp, data, datalen); 976 key_free(prv); 977 return (ret); 978} 979 980static int 981sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 982{ 983 Buffer b; 984 u_char *blob, *signature; 985 u_int bloblen, slen; 986 u_int skip = 0; 987 int ret = -1; 988 int have_sig = 1; 989 char *fp; 990 991 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 992 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 993 free(fp); 994 995 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 996 /* we cannot handle this key */ 997 debug3("sign_and_send_pubkey: cannot handle key"); 998 return 0; 999 } 1000 /* data to be signed */ 1001 buffer_init(&b); 1002 if (datafellows & SSH_OLD_SESSIONID) { 1003 buffer_append(&b, session_id2, session_id2_len); 1004 skip = session_id2_len; 1005 } else { 1006 buffer_put_string(&b, session_id2, session_id2_len); 1007 skip = buffer_len(&b); 1008 } 1009 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1010 buffer_put_cstring(&b, authctxt->server_user); 1011 buffer_put_cstring(&b, 1012 datafellows & SSH_BUG_PKSERVICE ? 1013 "ssh-userauth" : 1014 authctxt->service); 1015 if (datafellows & SSH_BUG_PKAUTH) { 1016 buffer_put_char(&b, have_sig); 1017 } else { 1018 buffer_put_cstring(&b, authctxt->method->name); 1019 buffer_put_char(&b, have_sig); 1020 buffer_put_cstring(&b, key_ssh_name(id->key)); 1021 } 1022 buffer_put_string(&b, blob, bloblen); 1023 1024 /* generate signature */ 1025 ret = identity_sign(id, &signature, &slen, 1026 buffer_ptr(&b), buffer_len(&b)); 1027 if (ret == -1) { 1028 free(blob); 1029 buffer_free(&b); 1030 return 0; 1031 } 1032#ifdef DEBUG_PK 1033 buffer_dump(&b); 1034#endif 1035 if (datafellows & SSH_BUG_PKSERVICE) { 1036 buffer_clear(&b); 1037 buffer_append(&b, session_id2, session_id2_len); 1038 skip = session_id2_len; 1039 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1040 buffer_put_cstring(&b, authctxt->server_user); 1041 buffer_put_cstring(&b, authctxt->service); 1042 buffer_put_cstring(&b, authctxt->method->name); 1043 buffer_put_char(&b, have_sig); 1044 if (!(datafellows & SSH_BUG_PKAUTH)) 1045 buffer_put_cstring(&b, key_ssh_name(id->key)); 1046 buffer_put_string(&b, blob, bloblen); 1047 } 1048 free(blob); 1049 1050 /* append signature */ 1051 buffer_put_string(&b, signature, slen); 1052 free(signature); 1053 1054 /* skip session id and packet type */ 1055 if (buffer_len(&b) < skip + 1) 1056 fatal("userauth_pubkey: internal error"); 1057 buffer_consume(&b, skip + 1); 1058 1059 /* put remaining data from buffer into packet */ 1060 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1061 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1062 buffer_free(&b); 1063 packet_send(); 1064 1065 return 1; 1066} 1067 1068static int 1069send_pubkey_test(Authctxt *authctxt, Identity *id) 1070{ 1071 u_char *blob; 1072 u_int bloblen, have_sig = 0; 1073 1074 debug3("send_pubkey_test"); 1075 1076 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1077 /* we cannot handle this key */ 1078 debug3("send_pubkey_test: cannot handle key"); 1079 return 0; 1080 } 1081 /* register callback for USERAUTH_PK_OK message */ 1082 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1083 1084 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1085 packet_put_cstring(authctxt->server_user); 1086 packet_put_cstring(authctxt->service); 1087 packet_put_cstring(authctxt->method->name); 1088 packet_put_char(have_sig); 1089 if (!(datafellows & SSH_BUG_PKAUTH)) 1090 packet_put_cstring(key_ssh_name(id->key)); 1091 packet_put_string(blob, bloblen); 1092 free(blob); 1093 packet_send(); 1094 return 1; 1095} 1096 1097static Key * 1098load_identity_file(char *filename, int userprovided) 1099{ 1100 Key *private; 1101 char prompt[300], *passphrase; 1102 int perm_ok = 0, quit, i; 1103 struct stat st; 1104 1105 if (stat(filename, &st) < 0) { 1106 (userprovided ? logit : debug3)("no such identity: %s: %s", 1107 filename, strerror(errno)); 1108 return NULL; 1109 } 1110 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1111 if (!perm_ok) { 1112 if (private != NULL) 1113 key_free(private); 1114 return NULL; 1115 } 1116 if (private == NULL) { 1117 if (options.batch_mode) 1118 return NULL; 1119 snprintf(prompt, sizeof prompt, 1120 "Enter passphrase for key '%.100s': ", filename); 1121 for (i = 0; i < options.number_of_password_prompts; i++) { 1122 passphrase = read_passphrase(prompt, 0); 1123 if (strcmp(passphrase, "") != 0) { 1124 private = key_load_private_type(KEY_UNSPEC, 1125 filename, passphrase, NULL, NULL); 1126 quit = 0; 1127 } else { 1128 debug2("no passphrase given, try next key"); 1129 quit = 1; 1130 } 1131 explicit_bzero(passphrase, strlen(passphrase)); 1132 free(passphrase); 1133 if (private != NULL || quit) 1134 break; 1135 debug2("bad passphrase given, try again..."); 1136 } 1137 } 1138 return private; 1139} 1140 1141/* 1142 * try keys in the following order: 1143 * 1. agent keys that are found in the config file 1144 * 2. other agent keys 1145 * 3. keys that are only listed in the config file 1146 */ 1147static void 1148pubkey_prepare(Authctxt *authctxt) 1149{ 1150 Identity *id, *id2, *tmp; 1151 Idlist agent, files, *preferred; 1152 Key *key; 1153 AuthenticationConnection *ac; 1154 char *comment; 1155 int i, found; 1156 1157 TAILQ_INIT(&agent); /* keys from the agent */ 1158 TAILQ_INIT(&files); /* keys from the config file */ 1159 preferred = &authctxt->keys; 1160 TAILQ_INIT(preferred); /* preferred order of keys */ 1161 1162 /* list of keys stored in the filesystem and PKCS#11 */ 1163 for (i = 0; i < options.num_identity_files; i++) { 1164 key = options.identity_keys[i]; 1165 if (key && key->type == KEY_RSA1) 1166 continue; 1167 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1168 continue; 1169 options.identity_keys[i] = NULL; 1170 id = xcalloc(1, sizeof(*id)); 1171 id->key = key; 1172 id->filename = xstrdup(options.identity_files[i]); 1173 id->userprovided = options.identity_file_userprovided[i]; 1174 TAILQ_INSERT_TAIL(&files, id, next); 1175 } 1176 /* Prefer PKCS11 keys that are explicitly listed */ 1177 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1178 if (id->key == NULL || (id->key->flags & KEY_FLAG_EXT) == 0) 1179 continue; 1180 found = 0; 1181 TAILQ_FOREACH(id2, &files, next) { 1182 if (id2->key == NULL || 1183 (id2->key->flags & KEY_FLAG_EXT) != 0) 1184 continue; 1185 if (key_equal(id->key, id2->key)) { 1186 TAILQ_REMOVE(&files, id, next); 1187 TAILQ_INSERT_TAIL(preferred, id, next); 1188 found = 1; 1189 break; 1190 } 1191 } 1192 /* If IdentitiesOnly set and key not found then don't use it */ 1193 if (!found && options.identities_only) { 1194 TAILQ_REMOVE(&files, id, next); 1195 explicit_bzero(id, sizeof(*id)); 1196 free(id); 1197 } 1198 } 1199 /* list of keys supported by the agent */ 1200 if ((ac = ssh_get_authentication_connection())) { 1201 for (key = ssh_get_first_identity(ac, &comment, 2); 1202 key != NULL; 1203 key = ssh_get_next_identity(ac, &comment, 2)) { 1204 found = 0; 1205 TAILQ_FOREACH(id, &files, next) { 1206 /* agent keys from the config file are preferred */ 1207 if (key_equal(key, id->key)) { 1208 key_free(key); 1209 free(comment); 1210 TAILQ_REMOVE(&files, id, next); 1211 TAILQ_INSERT_TAIL(preferred, id, next); 1212 id->ac = ac; 1213 found = 1; 1214 break; 1215 } 1216 } 1217 if (!found && !options.identities_only) { 1218 id = xcalloc(1, sizeof(*id)); 1219 id->key = key; 1220 id->filename = comment; 1221 id->ac = ac; 1222 TAILQ_INSERT_TAIL(&agent, id, next); 1223 } 1224 } 1225 /* append remaining agent keys */ 1226 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1227 TAILQ_REMOVE(&agent, id, next); 1228 TAILQ_INSERT_TAIL(preferred, id, next); 1229 } 1230 authctxt->agent = ac; 1231 } 1232 /* append remaining keys from the config file */ 1233 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1234 TAILQ_REMOVE(&files, id, next); 1235 TAILQ_INSERT_TAIL(preferred, id, next); 1236 } 1237 TAILQ_FOREACH(id, preferred, next) { 1238 debug2("key: %s (%p),%s", id->filename, id->key, 1239 id->userprovided ? " explicit" : ""); 1240 } 1241} 1242 1243static void 1244pubkey_cleanup(Authctxt *authctxt) 1245{ 1246 Identity *id; 1247 1248 if (authctxt->agent != NULL) 1249 ssh_close_authentication_connection(authctxt->agent); 1250 for (id = TAILQ_FIRST(&authctxt->keys); id; 1251 id = TAILQ_FIRST(&authctxt->keys)) { 1252 TAILQ_REMOVE(&authctxt->keys, id, next); 1253 if (id->key) 1254 key_free(id->key); 1255 free(id->filename); 1256 free(id); 1257 } 1258} 1259 1260int 1261userauth_pubkey(Authctxt *authctxt) 1262{ 1263 Identity *id; 1264 int sent = 0; 1265 1266 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1267 if (id->tried++) 1268 return (0); 1269 /* move key to the end of the queue */ 1270 TAILQ_REMOVE(&authctxt->keys, id, next); 1271 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1272 /* 1273 * send a test message if we have the public key. for 1274 * encrypted keys we cannot do this and have to load the 1275 * private key instead 1276 */ 1277 if (id->key != NULL) { 1278 if (key_type_plain(id->key->type) == KEY_RSA && 1279 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1280 debug("Skipped %s key %s for RSA/MD5 server", 1281 key_type(id->key), id->filename); 1282 } else if (id->key->type != KEY_RSA1) { 1283 debug("Offering %s public key: %s", 1284 key_type(id->key), id->filename); 1285 sent = send_pubkey_test(authctxt, id); 1286 } 1287 } else { 1288 debug("Trying private key: %s", id->filename); 1289 id->key = load_identity_file(id->filename, 1290 id->userprovided); 1291 if (id->key != NULL) { 1292 id->isprivate = 1; 1293 if (key_type_plain(id->key->type) == KEY_RSA && 1294 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1295 debug("Skipped %s key %s for RSA/MD5 " 1296 "server", key_type(id->key), 1297 id->filename); 1298 } else { 1299 sent = sign_and_send_pubkey( 1300 authctxt, id); 1301 } 1302 key_free(id->key); 1303 id->key = NULL; 1304 } 1305 } 1306 if (sent) 1307 return (sent); 1308 } 1309 return (0); 1310} 1311 1312/* 1313 * Send userauth request message specifying keyboard-interactive method. 1314 */ 1315int 1316userauth_kbdint(Authctxt *authctxt) 1317{ 1318 static int attempt = 0; 1319 1320 if (attempt++ >= options.number_of_password_prompts) 1321 return 0; 1322 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1323 if (attempt > 1 && !authctxt->info_req_seen) { 1324 debug3("userauth_kbdint: disable: no info_req_seen"); 1325 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1326 return 0; 1327 } 1328 1329 debug2("userauth_kbdint"); 1330 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1331 packet_put_cstring(authctxt->server_user); 1332 packet_put_cstring(authctxt->service); 1333 packet_put_cstring(authctxt->method->name); 1334 packet_put_cstring(""); /* lang */ 1335 packet_put_cstring(options.kbd_interactive_devices ? 1336 options.kbd_interactive_devices : ""); 1337 packet_send(); 1338 1339 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1340 return 1; 1341} 1342 1343/* 1344 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1345 */ 1346void 1347input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1348{ 1349 Authctxt *authctxt = ctxt; 1350 char *name, *inst, *lang, *prompt, *response; 1351 u_int num_prompts, i; 1352 int echo = 0; 1353 1354 debug2("input_userauth_info_req"); 1355 1356 if (authctxt == NULL) 1357 fatal("input_userauth_info_req: no authentication context"); 1358 1359 authctxt->info_req_seen = 1; 1360 1361 name = packet_get_string(NULL); 1362 inst = packet_get_string(NULL); 1363 lang = packet_get_string(NULL); 1364 if (strlen(name) > 0) 1365 logit("%s", name); 1366 if (strlen(inst) > 0) 1367 logit("%s", inst); 1368 free(name); 1369 free(inst); 1370 free(lang); 1371 1372 num_prompts = packet_get_int(); 1373 /* 1374 * Begin to build info response packet based on prompts requested. 1375 * We commit to providing the correct number of responses, so if 1376 * further on we run into a problem that prevents this, we have to 1377 * be sure and clean this up and send a correct error response. 1378 */ 1379 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1380 packet_put_int(num_prompts); 1381 1382 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1383 for (i = 0; i < num_prompts; i++) { 1384 prompt = packet_get_string(NULL); 1385 echo = packet_get_char(); 1386 1387 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1388 1389 packet_put_cstring(response); 1390 explicit_bzero(response, strlen(response)); 1391 free(response); 1392 free(prompt); 1393 } 1394 packet_check_eom(); /* done with parsing incoming message. */ 1395 1396 packet_add_padding(64); 1397 packet_send(); 1398} 1399 1400static int 1401ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1402 u_char *data, u_int datalen) 1403{ 1404 Buffer b; 1405 struct stat st; 1406 pid_t pid; 1407 int to[2], from[2], status, version = 2; 1408 1409 debug2("ssh_keysign called"); 1410 1411 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1412 error("ssh_keysign: not installed: %s", strerror(errno)); 1413 return -1; 1414 } 1415 if (fflush(stdout) != 0) 1416 error("ssh_keysign: fflush: %s", strerror(errno)); 1417 if (pipe(to) < 0) { 1418 error("ssh_keysign: pipe: %s", strerror(errno)); 1419 return -1; 1420 } 1421 if (pipe(from) < 0) { 1422 error("ssh_keysign: pipe: %s", strerror(errno)); 1423 return -1; 1424 } 1425 if ((pid = fork()) < 0) { 1426 error("ssh_keysign: fork: %s", strerror(errno)); 1427 return -1; 1428 } 1429 if (pid == 0) { 1430 /* keep the socket on exec */ 1431 fcntl(packet_get_connection_in(), F_SETFD, 0); 1432 permanently_drop_suid(getuid()); 1433 close(from[0]); 1434 if (dup2(from[1], STDOUT_FILENO) < 0) 1435 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1436 close(to[1]); 1437 if (dup2(to[0], STDIN_FILENO) < 0) 1438 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1439 close(from[1]); 1440 close(to[0]); 1441 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1442 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1443 strerror(errno)); 1444 } 1445 close(from[1]); 1446 close(to[0]); 1447 1448 buffer_init(&b); 1449 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1450 buffer_put_string(&b, data, datalen); 1451 if (ssh_msg_send(to[1], version, &b) == -1) 1452 fatal("ssh_keysign: couldn't send request"); 1453 1454 if (ssh_msg_recv(from[0], &b) < 0) { 1455 error("ssh_keysign: no reply"); 1456 buffer_free(&b); 1457 return -1; 1458 } 1459 close(from[0]); 1460 close(to[1]); 1461 1462 while (waitpid(pid, &status, 0) < 0) 1463 if (errno != EINTR) 1464 break; 1465 1466 if (buffer_get_char(&b) != version) { 1467 error("ssh_keysign: bad version"); 1468 buffer_free(&b); 1469 return -1; 1470 } 1471 *sigp = buffer_get_string(&b, lenp); 1472 buffer_free(&b); 1473 1474 return 0; 1475} 1476 1477int 1478userauth_hostbased(Authctxt *authctxt) 1479{ 1480 Key *private = NULL; 1481 Sensitive *sensitive = authctxt->sensitive; 1482 Buffer b; 1483 u_char *signature, *blob; 1484 char *chost, *pkalg, *p; 1485 const char *service; 1486 u_int blen, slen; 1487 int ok, i, found = 0; 1488 1489 /* check for a useful key */ 1490 for (i = 0; i < sensitive->nkeys; i++) { 1491 private = sensitive->keys[i]; 1492 if (private && private->type != KEY_RSA1) { 1493 found = 1; 1494 /* we take and free the key */ 1495 sensitive->keys[i] = NULL; 1496 break; 1497 } 1498 } 1499 if (!found) { 1500 debug("No more client hostkeys for hostbased authentication."); 1501 return 0; 1502 } 1503 if (key_to_blob(private, &blob, &blen) == 0) { 1504 key_free(private); 1505 return 0; 1506 } 1507 /* figure out a name for the client host */ 1508 p = get_local_name(packet_get_connection_in()); 1509 if (p == NULL) { 1510 error("userauth_hostbased: cannot get local ipaddr/name"); 1511 key_free(private); 1512 free(blob); 1513 return 0; 1514 } 1515 xasprintf(&chost, "%s.", p); 1516 debug2("userauth_hostbased: chost %s", chost); 1517 free(p); 1518 1519 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1520 authctxt->service; 1521 pkalg = xstrdup(key_ssh_name(private)); 1522 buffer_init(&b); 1523 /* construct data */ 1524 buffer_put_string(&b, session_id2, session_id2_len); 1525 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1526 buffer_put_cstring(&b, authctxt->server_user); 1527 buffer_put_cstring(&b, service); 1528 buffer_put_cstring(&b, authctxt->method->name); 1529 buffer_put_cstring(&b, pkalg); 1530 buffer_put_string(&b, blob, blen); 1531 buffer_put_cstring(&b, chost); 1532 buffer_put_cstring(&b, authctxt->local_user); 1533#ifdef DEBUG_PK 1534 buffer_dump(&b); 1535#endif 1536 if (sensitive->external_keysign) 1537 ok = ssh_keysign(private, &signature, &slen, 1538 buffer_ptr(&b), buffer_len(&b)); 1539 else 1540 ok = key_sign(private, &signature, &slen, 1541 buffer_ptr(&b), buffer_len(&b)); 1542 key_free(private); 1543 buffer_free(&b); 1544 if (ok != 0) { 1545 error("key_sign failed"); 1546 free(chost); 1547 free(pkalg); 1548 free(blob); 1549 return 0; 1550 } 1551 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1552 packet_put_cstring(authctxt->server_user); 1553 packet_put_cstring(authctxt->service); 1554 packet_put_cstring(authctxt->method->name); 1555 packet_put_cstring(pkalg); 1556 packet_put_string(blob, blen); 1557 packet_put_cstring(chost); 1558 packet_put_cstring(authctxt->local_user); 1559 packet_put_string(signature, slen); 1560 explicit_bzero(signature, slen); 1561 free(signature); 1562 free(chost); 1563 free(pkalg); 1564 free(blob); 1565 1566 packet_send(); 1567 return 1; 1568} 1569 1570/* find auth method */ 1571 1572/* 1573 * given auth method name, if configurable options permit this method fill 1574 * in auth_ident field and return true, otherwise return false. 1575 */ 1576static int 1577authmethod_is_enabled(Authmethod *method) 1578{ 1579 if (method == NULL) 1580 return 0; 1581 /* return false if options indicate this method is disabled */ 1582 if (method->enabled == NULL || *method->enabled == 0) 1583 return 0; 1584 /* return false if batch mode is enabled but method needs interactive mode */ 1585 if (method->batch_flag != NULL && *method->batch_flag != 0) 1586 return 0; 1587 return 1; 1588} 1589 1590static Authmethod * 1591authmethod_lookup(const char *name) 1592{ 1593 Authmethod *method = NULL; 1594 if (name != NULL) 1595 for (method = authmethods; method->name != NULL; method++) 1596 if (strcmp(name, method->name) == 0) 1597 return method; 1598 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1599 return NULL; 1600} 1601 1602/* XXX internal state */ 1603static Authmethod *current = NULL; 1604static char *supported = NULL; 1605static char *preferred = NULL; 1606 1607/* 1608 * Given the authentication method list sent by the server, return the 1609 * next method we should try. If the server initially sends a nil list, 1610 * use a built-in default list. 1611 */ 1612static Authmethod * 1613authmethod_get(char *authlist) 1614{ 1615 char *name = NULL; 1616 u_int next; 1617 1618 /* Use a suitable default if we're passed a nil list. */ 1619 if (authlist == NULL || strlen(authlist) == 0) 1620 authlist = options.preferred_authentications; 1621 1622 if (supported == NULL || strcmp(authlist, supported) != 0) { 1623 debug3("start over, passed a different list %s", authlist); 1624 free(supported); 1625 supported = xstrdup(authlist); 1626 preferred = options.preferred_authentications; 1627 debug3("preferred %s", preferred); 1628 current = NULL; 1629 } else if (current != NULL && authmethod_is_enabled(current)) 1630 return current; 1631 1632 for (;;) { 1633 if ((name = match_list(preferred, supported, &next)) == NULL) { 1634 debug("No more authentication methods to try."); 1635 current = NULL; 1636 return NULL; 1637 } 1638 preferred += next; 1639 debug3("authmethod_lookup %s", name); 1640 debug3("remaining preferred: %s", preferred); 1641 if ((current = authmethod_lookup(name)) != NULL && 1642 authmethod_is_enabled(current)) { 1643 debug3("authmethod_is_enabled %s", name); 1644 debug("Next authentication method: %s", name); 1645 free(name); 1646 return current; 1647 } 1648 free(name); 1649 } 1650} 1651 1652static char * 1653authmethods_get(void) 1654{ 1655 Authmethod *method = NULL; 1656 Buffer b; 1657 char *list; 1658 1659 buffer_init(&b); 1660 for (method = authmethods; method->name != NULL; method++) { 1661 if (authmethod_is_enabled(method)) { 1662 if (buffer_len(&b) > 0) 1663 buffer_append(&b, ",", 1); 1664 buffer_append(&b, method->name, strlen(method->name)); 1665 } 1666 } 1667 buffer_append(&b, "\0", 1); 1668 list = xstrdup(buffer_ptr(&b)); 1669 buffer_free(&b); 1670 return list; 1671} 1672 1673