sshconnect2.c revision 294333
1/* $OpenBSD: sshconnect2.c,v 1.223 2015/01/30 11:43:14 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 "misc.h" 65#include "readconf.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#include "ssherr.h" 74 75#ifdef GSSAPI 76#include "ssh-gss.h" 77#endif 78 79/* import */ 80extern char *client_version_string; 81extern char *server_version_string; 82extern Options options; 83 84/* 85 * SSH2 key exchange 86 */ 87 88u_char *session_id2 = NULL; 89u_int session_id2_len = 0; 90 91char *xxx_host; 92struct sockaddr *xxx_hostaddr; 93 94static int 95verify_host_key_callback(Key *hostkey, struct ssh *ssh) 96{ 97 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 98 fatal("Host key verification failed."); 99 return 0; 100} 101 102static char * 103order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 104{ 105 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 106 size_t maxlen; 107 struct hostkeys *hostkeys; 108 int ktype; 109 u_int i; 110 111 /* Find all hostkeys for this hostname */ 112 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 113 hostkeys = init_hostkeys(); 114 for (i = 0; i < options.num_user_hostfiles; i++) 115 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 116 for (i = 0; i < options.num_system_hostfiles; i++) 117 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 118 119 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 120 maxlen = strlen(avail) + 1; 121 first = xmalloc(maxlen); 122 last = xmalloc(maxlen); 123 *first = *last = '\0'; 124 125#define ALG_APPEND(to, from) \ 126 do { \ 127 if (*to != '\0') \ 128 strlcat(to, ",", maxlen); \ 129 strlcat(to, from, maxlen); \ 130 } while (0) 131 132 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 133 if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC) 134 fatal("%s: unknown alg %s", __func__, alg); 135 if (lookup_key_in_hostkeys_by_type(hostkeys, 136 sshkey_type_plain(ktype), NULL)) 137 ALG_APPEND(first, alg); 138 else 139 ALG_APPEND(last, alg); 140 } 141#undef ALG_APPEND 142 xasprintf(&ret, "%s%s%s", first, 143 (*first == '\0' || *last == '\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 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; 160 struct kex *kex; 161 int r; 162 163 xxx_host = host; 164 xxx_hostaddr = hostaddr; 165 166 if (options.ciphers == (char *)-1) { 167 logit("No valid ciphers for protocol version 2 given, using defaults."); 168 options.ciphers = NULL; 169 } 170 if (options.ciphers != NULL) { 171 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 172 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 173 } 174 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 175 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 176 myproposal[PROPOSAL_ENC_ALGS_STOC] = 177 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 178 if (options.compression) { 179 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 180 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 181 } else { 182 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 183 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 184 } 185 if (options.macs != NULL) { 186 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 187 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 188 } 189 if (options.hostkeyalgorithms != NULL) 190 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 191 compat_pkalg_proposal(options.hostkeyalgorithms); 192 else { 193 /* Prefer algorithms that we already have keys for */ 194 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 195 compat_pkalg_proposal( 196 order_hostkeyalgs(host, hostaddr, port)); 197 } 198 if (options.kex_algorithms != NULL) 199 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 200 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 201 myproposal[PROPOSAL_KEX_ALGS]); 202 203 if (options.rekey_limit || options.rekey_interval) 204 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 205 (time_t)options.rekey_interval); 206 207 /* start key exchange */ 208 if ((r = kex_setup(active_state, myproposal)) != 0) 209 fatal("kex_setup: %s", ssh_err(r)); 210 kex = active_state->kex; 211#ifdef WITH_OPENSSL 212 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 213 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 214 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 215 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 216# ifdef OPENSSL_HAS_ECC 217 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 218# endif 219#endif 220 kex->kex[KEX_C25519_SHA256] = kexc25519_client; 221 kex->client_version_string=client_version_string; 222 kex->server_version_string=server_version_string; 223 kex->verify_host_key=&verify_host_key_callback; 224 225 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); 226 227 if (options.use_roaming && !kex->roaming) { 228 debug("Roaming not allowed by server"); 229 options.use_roaming = 0; 230 } 231 232 session_id2 = kex->session_id; 233 session_id2_len = kex->session_id_len; 234 235#ifdef DEBUG_KEXDH 236 /* send 1st encrypted/maced/compressed message */ 237 packet_start(SSH2_MSG_IGNORE); 238 packet_put_cstring("markus"); 239 packet_send(); 240 packet_write_wait(); 241#endif 242} 243 244/* 245 * Authenticate user 246 */ 247 248typedef struct cauthctxt Authctxt; 249typedef struct cauthmethod Authmethod; 250typedef struct identity Identity; 251typedef struct idlist Idlist; 252 253struct identity { 254 TAILQ_ENTRY(identity) next; 255 int agent_fd; /* >=0 if agent supports key */ 256 struct sshkey *key; /* public/private key */ 257 char *filename; /* comment for agent-only keys */ 258 int tried; 259 int isprivate; /* key points to the private key */ 260 int userprovided; 261}; 262TAILQ_HEAD(idlist, identity); 263 264struct cauthctxt { 265 const char *server_user; 266 const char *local_user; 267 const char *host; 268 const char *service; 269 struct cauthmethod *method; 270 sig_atomic_t success; 271 char *authlist; 272 int attempt; 273 /* pubkey */ 274 struct idlist keys; 275 int agent_fd; 276 /* hostbased */ 277 Sensitive *sensitive; 278 char *oktypes, *ktypes; 279 const char *active_ktype; 280 /* kbd-interactive */ 281 int info_req_seen; 282 /* generic */ 283 void *methoddata; 284}; 285 286struct cauthmethod { 287 char *name; /* string to compare against server's list */ 288 int (*userauth)(Authctxt *authctxt); 289 void (*cleanup)(Authctxt *authctxt); 290 int *enabled; /* flag in option struct that enables method */ 291 int *batch_flag; /* flag in option struct that disables method */ 292}; 293 294int input_userauth_success(int, u_int32_t, void *); 295int input_userauth_success_unexpected(int, u_int32_t, void *); 296int input_userauth_failure(int, u_int32_t, void *); 297int input_userauth_banner(int, u_int32_t, void *); 298int input_userauth_error(int, u_int32_t, void *); 299int input_userauth_info_req(int, u_int32_t, void *); 300int input_userauth_pk_ok(int, u_int32_t, void *); 301int input_userauth_passwd_changereq(int, u_int32_t, void *); 302 303int userauth_none(Authctxt *); 304int userauth_pubkey(Authctxt *); 305int userauth_passwd(Authctxt *); 306int userauth_kbdint(Authctxt *); 307int userauth_hostbased(Authctxt *); 308 309#ifdef GSSAPI 310int userauth_gssapi(Authctxt *authctxt); 311int input_gssapi_response(int type, u_int32_t, void *); 312int input_gssapi_token(int type, u_int32_t, void *); 313int input_gssapi_hash(int type, u_int32_t, void *); 314int input_gssapi_error(int, u_int32_t, void *); 315int input_gssapi_errtok(int, u_int32_t, void *); 316#endif 317 318void userauth(Authctxt *, char *); 319 320static int sign_and_send_pubkey(Authctxt *, Identity *); 321static void pubkey_prepare(Authctxt *); 322static void pubkey_cleanup(Authctxt *); 323static Key *load_identity_file(char *, int); 324 325static Authmethod *authmethod_get(char *authlist); 326static Authmethod *authmethod_lookup(const char *name); 327static char *authmethods_get(void); 328 329Authmethod authmethods[] = { 330#ifdef GSSAPI 331 {"gssapi-with-mic", 332 userauth_gssapi, 333 NULL, 334 &options.gss_authentication, 335 NULL}, 336#endif 337 {"hostbased", 338 userauth_hostbased, 339 NULL, 340 &options.hostbased_authentication, 341 NULL}, 342 {"publickey", 343 userauth_pubkey, 344 NULL, 345 &options.pubkey_authentication, 346 NULL}, 347 {"keyboard-interactive", 348 userauth_kbdint, 349 NULL, 350 &options.kbd_interactive_authentication, 351 &options.batch_mode}, 352 {"password", 353 userauth_passwd, 354 NULL, 355 &options.password_authentication, 356 &options.batch_mode}, 357 {"none", 358 userauth_none, 359 NULL, 360 NULL, 361 NULL}, 362 {NULL, NULL, NULL, NULL, NULL} 363}; 364 365void 366ssh_userauth2(const char *local_user, const char *server_user, char *host, 367 Sensitive *sensitive) 368{ 369 Authctxt authctxt; 370 int type; 371 372 if (options.challenge_response_authentication) 373 options.kbd_interactive_authentication = 1; 374 375 packet_start(SSH2_MSG_SERVICE_REQUEST); 376 packet_put_cstring("ssh-userauth"); 377 packet_send(); 378 debug("SSH2_MSG_SERVICE_REQUEST sent"); 379 packet_write_wait(); 380 type = packet_read(); 381 if (type != SSH2_MSG_SERVICE_ACCEPT) 382 fatal("Server denied authentication request: %d", type); 383 if (packet_remaining() > 0) { 384 char *reply = packet_get_string(NULL); 385 debug2("service_accept: %s", reply); 386 free(reply); 387 } else { 388 debug2("buggy server: service_accept w/o service"); 389 } 390 packet_check_eom(); 391 debug("SSH2_MSG_SERVICE_ACCEPT received"); 392 393 if (options.preferred_authentications == NULL) 394 options.preferred_authentications = authmethods_get(); 395 396 /* setup authentication context */ 397 memset(&authctxt, 0, sizeof(authctxt)); 398 pubkey_prepare(&authctxt); 399 authctxt.server_user = server_user; 400 authctxt.local_user = local_user; 401 authctxt.host = host; 402 authctxt.service = "ssh-connection"; /* service name */ 403 authctxt.success = 0; 404 authctxt.method = authmethod_lookup("none"); 405 authctxt.authlist = NULL; 406 authctxt.methoddata = NULL; 407 authctxt.sensitive = sensitive; 408 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 409 authctxt.info_req_seen = 0; 410 authctxt.agent_fd = -1; 411 if (authctxt.method == NULL) 412 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 413 414 /* initial userauth request */ 415 userauth_none(&authctxt); 416 417 dispatch_init(&input_userauth_error); 418 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 419 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 420 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 421 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 422 423 pubkey_cleanup(&authctxt); 424 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 425 426 debug("Authentication succeeded (%s).", authctxt.method->name); 427} 428 429void 430userauth(Authctxt *authctxt, char *authlist) 431{ 432 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 433 authctxt->method->cleanup(authctxt); 434 435 free(authctxt->methoddata); 436 authctxt->methoddata = NULL; 437 if (authlist == NULL) { 438 authlist = authctxt->authlist; 439 } else { 440 free(authctxt->authlist); 441 authctxt->authlist = authlist; 442 } 443 for (;;) { 444 Authmethod *method = authmethod_get(authlist); 445 if (method == NULL) 446 fatal("Permission denied (%s).", authlist); 447 authctxt->method = method; 448 449 /* reset the per method handler */ 450 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 451 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 452 453 /* and try new method */ 454 if (method->userauth(authctxt) != 0) { 455 debug2("we sent a %s packet, wait for reply", method->name); 456 break; 457 } else { 458 debug2("we did not send a packet, disable method"); 459 method->enabled = NULL; 460 } 461 } 462} 463 464/* ARGSUSED */ 465int 466input_userauth_error(int type, u_int32_t seq, void *ctxt) 467{ 468 fatal("input_userauth_error: bad message during authentication: " 469 "type %d", type); 470 return 0; 471} 472 473/* ARGSUSED */ 474int 475input_userauth_banner(int type, u_int32_t seq, void *ctxt) 476{ 477 char *msg, *raw, *lang; 478 u_int len; 479 480 debug3("input_userauth_banner"); 481 raw = packet_get_string(&len); 482 lang = packet_get_string(NULL); 483 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 484 if (len > 65536) 485 len = 65536; 486 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 487 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 488 fprintf(stderr, "%s", msg); 489 free(msg); 490 } 491 free(raw); 492 free(lang); 493 return 0; 494} 495 496/* ARGSUSED */ 497int 498input_userauth_success(int type, u_int32_t seq, void *ctxt) 499{ 500 Authctxt *authctxt = ctxt; 501 502 if (authctxt == NULL) 503 fatal("input_userauth_success: no authentication context"); 504 free(authctxt->authlist); 505 authctxt->authlist = NULL; 506 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 507 authctxt->method->cleanup(authctxt); 508 free(authctxt->methoddata); 509 authctxt->methoddata = NULL; 510 authctxt->success = 1; /* break out */ 511 return 0; 512} 513 514int 515input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 516{ 517 Authctxt *authctxt = ctxt; 518 519 if (authctxt == NULL) 520 fatal("%s: no authentication context", __func__); 521 522 fatal("Unexpected authentication success during %s.", 523 authctxt->method->name); 524 return 0; 525} 526 527/* ARGSUSED */ 528int 529input_userauth_failure(int type, u_int32_t seq, void *ctxt) 530{ 531 Authctxt *authctxt = ctxt; 532 char *authlist = NULL; 533 int partial; 534 535 if (authctxt == NULL) 536 fatal("input_userauth_failure: no authentication context"); 537 538 authlist = packet_get_string(NULL); 539 partial = packet_get_char(); 540 packet_check_eom(); 541 542 if (partial != 0) { 543 logit("Authenticated with partial success."); 544 /* reset state */ 545 pubkey_cleanup(authctxt); 546 pubkey_prepare(authctxt); 547 } 548 debug("Authentications that can continue: %s", authlist); 549 550 userauth(authctxt, authlist); 551 return 0; 552} 553 554/* ARGSUSED */ 555int 556input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 557{ 558 Authctxt *authctxt = ctxt; 559 Key *key = NULL; 560 Identity *id = NULL; 561 Buffer b; 562 int pktype, sent = 0; 563 u_int alen, blen; 564 char *pkalg, *fp; 565 u_char *pkblob; 566 567 if (authctxt == NULL) 568 fatal("input_userauth_pk_ok: no authentication context"); 569 if (datafellows & SSH_BUG_PKOK) { 570 /* this is similar to SSH_BUG_PKAUTH */ 571 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 572 pkblob = packet_get_string(&blen); 573 buffer_init(&b); 574 buffer_append(&b, pkblob, blen); 575 pkalg = buffer_get_string(&b, &alen); 576 buffer_free(&b); 577 } else { 578 pkalg = packet_get_string(&alen); 579 pkblob = packet_get_string(&blen); 580 } 581 packet_check_eom(); 582 583 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 584 585 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 586 debug("unknown pkalg %s", pkalg); 587 goto done; 588 } 589 if ((key = key_from_blob(pkblob, blen)) == NULL) { 590 debug("no key from blob. pkalg %s", pkalg); 591 goto done; 592 } 593 if (key->type != pktype) { 594 error("input_userauth_pk_ok: type mismatch " 595 "for decoded key (received %d, expected %d)", 596 key->type, pktype); 597 goto done; 598 } 599 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 600 SSH_FP_DEFAULT)) == NULL) 601 goto done; 602 debug2("input_userauth_pk_ok: fp %s", fp); 603 free(fp); 604 605 /* 606 * search keys in the reverse order, because last candidate has been 607 * moved to the end of the queue. this also avoids confusion by 608 * duplicate keys 609 */ 610 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 611 if (key_equal(key, id->key)) { 612 sent = sign_and_send_pubkey(authctxt, id); 613 break; 614 } 615 } 616done: 617 if (key != NULL) 618 key_free(key); 619 free(pkalg); 620 free(pkblob); 621 622 /* try another method if we did not send a packet */ 623 if (sent == 0) 624 userauth(authctxt, NULL); 625 return 0; 626} 627 628#ifdef GSSAPI 629int 630userauth_gssapi(Authctxt *authctxt) 631{ 632 Gssctxt *gssctxt = NULL; 633 static gss_OID_set gss_supported = NULL; 634 static u_int mech = 0; 635 OM_uint32 min; 636 int ok = 0; 637 638 /* Try one GSSAPI method at a time, rather than sending them all at 639 * once. */ 640 641 if (gss_supported == NULL) 642 gss_indicate_mechs(&min, &gss_supported); 643 644 /* Check to see if the mechanism is usable before we offer it */ 645 while (mech < gss_supported->count && !ok) { 646 /* My DER encoding requires length<128 */ 647 if (gss_supported->elements[mech].length < 128 && 648 ssh_gssapi_check_mechanism(&gssctxt, 649 &gss_supported->elements[mech], authctxt->host)) { 650 ok = 1; /* Mechanism works */ 651 } else { 652 mech++; 653 } 654 } 655 656 if (!ok) 657 return 0; 658 659 authctxt->methoddata=(void *)gssctxt; 660 661 packet_start(SSH2_MSG_USERAUTH_REQUEST); 662 packet_put_cstring(authctxt->server_user); 663 packet_put_cstring(authctxt->service); 664 packet_put_cstring(authctxt->method->name); 665 666 packet_put_int(1); 667 668 packet_put_int((gss_supported->elements[mech].length) + 2); 669 packet_put_char(SSH_GSS_OIDTYPE); 670 packet_put_char(gss_supported->elements[mech].length); 671 packet_put_raw(gss_supported->elements[mech].elements, 672 gss_supported->elements[mech].length); 673 674 packet_send(); 675 676 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 677 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 678 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 679 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 680 681 mech++; /* Move along to next candidate */ 682 683 return 1; 684} 685 686static OM_uint32 687process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 688{ 689 Authctxt *authctxt = ctxt; 690 Gssctxt *gssctxt = authctxt->methoddata; 691 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 692 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 693 gss_buffer_desc gssbuf; 694 OM_uint32 status, ms, flags; 695 Buffer b; 696 697 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 698 recv_tok, &send_tok, &flags); 699 700 if (send_tok.length > 0) { 701 if (GSS_ERROR(status)) 702 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 703 else 704 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 705 706 packet_put_string(send_tok.value, send_tok.length); 707 packet_send(); 708 gss_release_buffer(&ms, &send_tok); 709 } 710 711 if (status == GSS_S_COMPLETE) { 712 /* send either complete or MIC, depending on mechanism */ 713 if (!(flags & GSS_C_INTEG_FLAG)) { 714 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 715 packet_send(); 716 } else { 717 ssh_gssapi_buildmic(&b, authctxt->server_user, 718 authctxt->service, "gssapi-with-mic"); 719 720 gssbuf.value = buffer_ptr(&b); 721 gssbuf.length = buffer_len(&b); 722 723 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 724 725 if (!GSS_ERROR(status)) { 726 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 727 packet_put_string(mic.value, mic.length); 728 729 packet_send(); 730 } 731 732 buffer_free(&b); 733 gss_release_buffer(&ms, &mic); 734 } 735 } 736 737 return status; 738} 739 740/* ARGSUSED */ 741int 742input_gssapi_response(int type, u_int32_t plen, void *ctxt) 743{ 744 Authctxt *authctxt = ctxt; 745 Gssctxt *gssctxt; 746 int oidlen; 747 char *oidv; 748 749 if (authctxt == NULL) 750 fatal("input_gssapi_response: no authentication context"); 751 gssctxt = authctxt->methoddata; 752 753 /* Setup our OID */ 754 oidv = packet_get_string(&oidlen); 755 756 if (oidlen <= 2 || 757 oidv[0] != SSH_GSS_OIDTYPE || 758 oidv[1] != oidlen - 2) { 759 free(oidv); 760 debug("Badly encoded mechanism OID received"); 761 userauth(authctxt, NULL); 762 return 0; 763 } 764 765 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 766 fatal("Server returned different OID than expected"); 767 768 packet_check_eom(); 769 770 free(oidv); 771 772 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 773 /* Start again with next method on list */ 774 debug("Trying to start again"); 775 userauth(authctxt, NULL); 776 return 0; 777 } 778 return 0; 779} 780 781/* ARGSUSED */ 782int 783input_gssapi_token(int type, u_int32_t plen, void *ctxt) 784{ 785 Authctxt *authctxt = ctxt; 786 gss_buffer_desc recv_tok; 787 OM_uint32 status; 788 u_int slen; 789 790 if (authctxt == NULL) 791 fatal("input_gssapi_response: no authentication context"); 792 793 recv_tok.value = packet_get_string(&slen); 794 recv_tok.length = slen; /* safe typecast */ 795 796 packet_check_eom(); 797 798 status = process_gssapi_token(ctxt, &recv_tok); 799 800 free(recv_tok.value); 801 802 if (GSS_ERROR(status)) { 803 /* Start again with the next method in the list */ 804 userauth(authctxt, NULL); 805 return 0; 806 } 807 return 0; 808} 809 810/* ARGSUSED */ 811int 812input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 813{ 814 Authctxt *authctxt = ctxt; 815 Gssctxt *gssctxt; 816 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 817 gss_buffer_desc recv_tok; 818 OM_uint32 ms; 819 u_int len; 820 821 if (authctxt == NULL) 822 fatal("input_gssapi_response: no authentication context"); 823 gssctxt = authctxt->methoddata; 824 825 recv_tok.value = packet_get_string(&len); 826 recv_tok.length = len; 827 828 packet_check_eom(); 829 830 /* Stick it into GSSAPI and see what it says */ 831 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 832 &recv_tok, &send_tok, NULL); 833 834 free(recv_tok.value); 835 gss_release_buffer(&ms, &send_tok); 836 837 /* Server will be returning a failed packet after this one */ 838 return 0; 839} 840 841/* ARGSUSED */ 842int 843input_gssapi_error(int type, u_int32_t plen, void *ctxt) 844{ 845 char *msg; 846 char *lang; 847 848 /* maj */(void)packet_get_int(); 849 /* min */(void)packet_get_int(); 850 msg=packet_get_string(NULL); 851 lang=packet_get_string(NULL); 852 853 packet_check_eom(); 854 855 debug("Server GSSAPI Error:\n%s", msg); 856 free(msg); 857 free(lang); 858 return 0; 859} 860#endif /* GSSAPI */ 861 862int 863userauth_none(Authctxt *authctxt) 864{ 865 /* initial userauth request */ 866 packet_start(SSH2_MSG_USERAUTH_REQUEST); 867 packet_put_cstring(authctxt->server_user); 868 packet_put_cstring(authctxt->service); 869 packet_put_cstring(authctxt->method->name); 870 packet_send(); 871 return 1; 872} 873 874int 875userauth_passwd(Authctxt *authctxt) 876{ 877 static int attempt = 0; 878 char prompt[150]; 879 char *password; 880 const char *host = options.host_key_alias ? options.host_key_alias : 881 authctxt->host; 882 883 if (attempt++ >= options.number_of_password_prompts) 884 return 0; 885 886 if (attempt != 1) 887 error("Permission denied, please try again."); 888 889 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 890 authctxt->server_user, host); 891 password = read_passphrase(prompt, 0); 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_put_char(0); 897 packet_put_cstring(password); 898 explicit_bzero(password, strlen(password)); 899 free(password); 900 packet_add_padding(64); 901 packet_send(); 902 903 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 904 &input_userauth_passwd_changereq); 905 906 return 1; 907} 908 909/* 910 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 911 */ 912/* ARGSUSED */ 913int 914input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 915{ 916 Authctxt *authctxt = ctxt; 917 char *info, *lang, *password = NULL, *retype = NULL; 918 char prompt[150]; 919 const char *host = options.host_key_alias ? options.host_key_alias : 920 authctxt->host; 921 922 debug2("input_userauth_passwd_changereq"); 923 924 if (authctxt == NULL) 925 fatal("input_userauth_passwd_changereq: " 926 "no authentication context"); 927 928 info = packet_get_string(NULL); 929 lang = packet_get_string(NULL); 930 if (strlen(info) > 0) 931 logit("%s", info); 932 free(info); 933 free(lang); 934 packet_start(SSH2_MSG_USERAUTH_REQUEST); 935 packet_put_cstring(authctxt->server_user); 936 packet_put_cstring(authctxt->service); 937 packet_put_cstring(authctxt->method->name); 938 packet_put_char(1); /* additional info */ 939 snprintf(prompt, sizeof(prompt), 940 "Enter %.30s@%.128s's old password: ", 941 authctxt->server_user, host); 942 password = read_passphrase(prompt, 0); 943 packet_put_cstring(password); 944 explicit_bzero(password, strlen(password)); 945 free(password); 946 password = NULL; 947 while (password == NULL) { 948 snprintf(prompt, sizeof(prompt), 949 "Enter %.30s@%.128s's new password: ", 950 authctxt->server_user, host); 951 password = read_passphrase(prompt, RP_ALLOW_EOF); 952 if (password == NULL) { 953 /* bail out */ 954 return 0; 955 } 956 snprintf(prompt, sizeof(prompt), 957 "Retype %.30s@%.128s's new password: ", 958 authctxt->server_user, host); 959 retype = read_passphrase(prompt, 0); 960 if (strcmp(password, retype) != 0) { 961 explicit_bzero(password, strlen(password)); 962 free(password); 963 logit("Mismatch; try again, EOF to quit."); 964 password = NULL; 965 } 966 explicit_bzero(retype, strlen(retype)); 967 free(retype); 968 } 969 packet_put_cstring(password); 970 explicit_bzero(password, strlen(password)); 971 free(password); 972 packet_add_padding(64); 973 packet_send(); 974 975 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 976 &input_userauth_passwd_changereq); 977 return 0; 978} 979 980static int 981identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 982 const u_char *data, size_t datalen, u_int compat) 983{ 984 Key *prv; 985 int ret; 986 987 /* the agent supports this key */ 988 if (id->agent_fd) 989 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 990 data, datalen, compat); 991 992 /* 993 * we have already loaded the private key or 994 * the private key is stored in external hardware 995 */ 996 if (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT)) 997 return (sshkey_sign(id->key, sigp, lenp, data, datalen, 998 compat)); 999 /* load the private key from the file */ 1000 if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL) 1001 return (-1); /* XXX return decent error code */ 1002 ret = sshkey_sign(prv, sigp, lenp, data, datalen, compat); 1003 sshkey_free(prv); 1004 return (ret); 1005} 1006 1007static int 1008sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1009{ 1010 Buffer b; 1011 u_char *blob, *signature; 1012 u_int bloblen; 1013 size_t slen; 1014 u_int skip = 0; 1015 int ret = -1; 1016 int have_sig = 1; 1017 char *fp; 1018 1019 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1020 SSH_FP_DEFAULT)) == NULL) 1021 return 0; 1022 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1023 free(fp); 1024 1025 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1026 /* we cannot handle this key */ 1027 debug3("sign_and_send_pubkey: cannot handle key"); 1028 return 0; 1029 } 1030 /* data to be signed */ 1031 buffer_init(&b); 1032 if (datafellows & SSH_OLD_SESSIONID) { 1033 buffer_append(&b, session_id2, session_id2_len); 1034 skip = session_id2_len; 1035 } else { 1036 buffer_put_string(&b, session_id2, session_id2_len); 1037 skip = buffer_len(&b); 1038 } 1039 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1040 buffer_put_cstring(&b, authctxt->server_user); 1041 buffer_put_cstring(&b, 1042 datafellows & SSH_BUG_PKSERVICE ? 1043 "ssh-userauth" : 1044 authctxt->service); 1045 if (datafellows & SSH_BUG_PKAUTH) { 1046 buffer_put_char(&b, have_sig); 1047 } else { 1048 buffer_put_cstring(&b, authctxt->method->name); 1049 buffer_put_char(&b, have_sig); 1050 buffer_put_cstring(&b, key_ssh_name(id->key)); 1051 } 1052 buffer_put_string(&b, blob, bloblen); 1053 1054 /* generate signature */ 1055 ret = identity_sign(id, &signature, &slen, 1056 buffer_ptr(&b), buffer_len(&b), datafellows); 1057 if (ret != 0) { 1058 free(blob); 1059 buffer_free(&b); 1060 return 0; 1061 } 1062#ifdef DEBUG_PK 1063 buffer_dump(&b); 1064#endif 1065 if (datafellows & SSH_BUG_PKSERVICE) { 1066 buffer_clear(&b); 1067 buffer_append(&b, session_id2, session_id2_len); 1068 skip = session_id2_len; 1069 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1070 buffer_put_cstring(&b, authctxt->server_user); 1071 buffer_put_cstring(&b, authctxt->service); 1072 buffer_put_cstring(&b, authctxt->method->name); 1073 buffer_put_char(&b, have_sig); 1074 if (!(datafellows & SSH_BUG_PKAUTH)) 1075 buffer_put_cstring(&b, key_ssh_name(id->key)); 1076 buffer_put_string(&b, blob, bloblen); 1077 } 1078 free(blob); 1079 1080 /* append signature */ 1081 buffer_put_string(&b, signature, slen); 1082 free(signature); 1083 1084 /* skip session id and packet type */ 1085 if (buffer_len(&b) < skip + 1) 1086 fatal("userauth_pubkey: internal error"); 1087 buffer_consume(&b, skip + 1); 1088 1089 /* put remaining data from buffer into packet */ 1090 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1091 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1092 buffer_free(&b); 1093 packet_send(); 1094 1095 return 1; 1096} 1097 1098static int 1099send_pubkey_test(Authctxt *authctxt, Identity *id) 1100{ 1101 u_char *blob; 1102 u_int bloblen, have_sig = 0; 1103 1104 debug3("send_pubkey_test"); 1105 1106 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1107 /* we cannot handle this key */ 1108 debug3("send_pubkey_test: cannot handle key"); 1109 return 0; 1110 } 1111 /* register callback for USERAUTH_PK_OK message */ 1112 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1113 1114 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1115 packet_put_cstring(authctxt->server_user); 1116 packet_put_cstring(authctxt->service); 1117 packet_put_cstring(authctxt->method->name); 1118 packet_put_char(have_sig); 1119 if (!(datafellows & SSH_BUG_PKAUTH)) 1120 packet_put_cstring(key_ssh_name(id->key)); 1121 packet_put_string(blob, bloblen); 1122 free(blob); 1123 packet_send(); 1124 return 1; 1125} 1126 1127static Key * 1128load_identity_file(char *filename, int userprovided) 1129{ 1130 Key *private; 1131 char prompt[300], *passphrase; 1132 int r, perm_ok = 0, quit = 0, i; 1133 struct stat st; 1134 1135 if (stat(filename, &st) < 0) { 1136 (userprovided ? logit : debug3)("no such identity: %s: %s", 1137 filename, strerror(errno)); 1138 return NULL; 1139 } 1140 snprintf(prompt, sizeof prompt, 1141 "Enter passphrase for key '%.100s': ", filename); 1142 for (i = 0; i <= options.number_of_password_prompts; i++) { 1143 if (i == 0) 1144 passphrase = ""; 1145 else { 1146 passphrase = read_passphrase(prompt, 0); 1147 if (*passphrase == '\0') { 1148 debug2("no passphrase given, try next key"); 1149 free(passphrase); 1150 break; 1151 } 1152 } 1153 switch ((r = sshkey_load_private_type(KEY_UNSPEC, filename, 1154 passphrase, &private, NULL, &perm_ok))) { 1155 case 0: 1156 break; 1157 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1158 if (options.batch_mode) { 1159 quit = 1; 1160 break; 1161 } 1162 if (i != 0) 1163 debug2("bad passphrase given, try again..."); 1164 break; 1165 case SSH_ERR_SYSTEM_ERROR: 1166 if (errno == ENOENT) { 1167 debug2("Load key \"%s\": %s", 1168 filename, ssh_err(r)); 1169 quit = 1; 1170 break; 1171 } 1172 /* FALLTHROUGH */ 1173 default: 1174 error("Load key \"%s\": %s", filename, ssh_err(r)); 1175 quit = 1; 1176 break; 1177 } 1178 if (i > 0) { 1179 explicit_bzero(passphrase, strlen(passphrase)); 1180 free(passphrase); 1181 } 1182 if (private != NULL || quit) 1183 break; 1184 } 1185 return private; 1186} 1187 1188/* 1189 * try keys in the following order: 1190 * 1. agent keys that are found in the config file 1191 * 2. other agent keys 1192 * 3. keys that are only listed in the config file 1193 */ 1194static void 1195pubkey_prepare(Authctxt *authctxt) 1196{ 1197 struct identity *id, *id2, *tmp; 1198 struct idlist agent, files, *preferred; 1199 struct sshkey *key; 1200 int agent_fd, i, r, found; 1201 size_t j; 1202 struct ssh_identitylist *idlist; 1203 1204 TAILQ_INIT(&agent); /* keys from the agent */ 1205 TAILQ_INIT(&files); /* keys from the config file */ 1206 preferred = &authctxt->keys; 1207 TAILQ_INIT(preferred); /* preferred order of keys */ 1208 1209 /* list of keys stored in the filesystem and PKCS#11 */ 1210 for (i = 0; i < options.num_identity_files; i++) { 1211 key = options.identity_keys[i]; 1212 if (key && key->type == KEY_RSA1) 1213 continue; 1214 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1215 continue; 1216 options.identity_keys[i] = NULL; 1217 id = xcalloc(1, sizeof(*id)); 1218 id->key = key; 1219 id->filename = xstrdup(options.identity_files[i]); 1220 id->userprovided = options.identity_file_userprovided[i]; 1221 TAILQ_INSERT_TAIL(&files, id, next); 1222 } 1223 /* Prefer PKCS11 keys that are explicitly listed */ 1224 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1225 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1226 continue; 1227 found = 0; 1228 TAILQ_FOREACH(id2, &files, next) { 1229 if (id2->key == NULL || 1230 (id2->key->flags & SSHKEY_FLAG_EXT) == 0) 1231 continue; 1232 if (sshkey_equal(id->key, id2->key)) { 1233 TAILQ_REMOVE(&files, id, next); 1234 TAILQ_INSERT_TAIL(preferred, id, next); 1235 found = 1; 1236 break; 1237 } 1238 } 1239 /* If IdentitiesOnly set and key not found then don't use it */ 1240 if (!found && options.identities_only) { 1241 TAILQ_REMOVE(&files, id, next); 1242 explicit_bzero(id, sizeof(*id)); 1243 free(id); 1244 } 1245 } 1246 /* list of keys supported by the agent */ 1247 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1248 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1249 debug("%s: ssh_get_authentication_socket: %s", 1250 __func__, ssh_err(r)); 1251 } else if ((r = ssh_fetch_identitylist(agent_fd, 2, &idlist)) != 0) { 1252 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1253 debug("%s: ssh_fetch_identitylist: %s", 1254 __func__, ssh_err(r)); 1255 } else { 1256 for (j = 0; j < idlist->nkeys; j++) { 1257 found = 0; 1258 TAILQ_FOREACH(id, &files, next) { 1259 /* 1260 * agent keys from the config file are 1261 * preferred 1262 */ 1263 if (sshkey_equal(idlist->keys[j], id->key)) { 1264 TAILQ_REMOVE(&files, id, next); 1265 TAILQ_INSERT_TAIL(preferred, id, next); 1266 id->agent_fd = agent_fd; 1267 found = 1; 1268 break; 1269 } 1270 } 1271 if (!found && !options.identities_only) { 1272 id = xcalloc(1, sizeof(*id)); 1273 /* XXX "steals" key/comment from idlist */ 1274 id->key = idlist->keys[j]; 1275 id->filename = idlist->comments[j]; 1276 idlist->keys[j] = NULL; 1277 idlist->comments[j] = NULL; 1278 id->agent_fd = agent_fd; 1279 TAILQ_INSERT_TAIL(&agent, id, next); 1280 } 1281 } 1282 ssh_free_identitylist(idlist); 1283 /* append remaining agent keys */ 1284 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1285 TAILQ_REMOVE(&agent, id, next); 1286 TAILQ_INSERT_TAIL(preferred, id, next); 1287 } 1288 authctxt->agent_fd = agent_fd; 1289 } 1290 /* append remaining keys from the config file */ 1291 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1292 TAILQ_REMOVE(&files, id, next); 1293 TAILQ_INSERT_TAIL(preferred, id, next); 1294 } 1295 TAILQ_FOREACH(id, preferred, next) { 1296 debug2("key: %s (%p),%s", id->filename, id->key, 1297 id->userprovided ? " explicit" : ""); 1298 } 1299} 1300 1301static void 1302pubkey_cleanup(Authctxt *authctxt) 1303{ 1304 Identity *id; 1305 1306 if (authctxt->agent_fd != -1) 1307 ssh_close_authentication_socket(authctxt->agent_fd); 1308 for (id = TAILQ_FIRST(&authctxt->keys); id; 1309 id = TAILQ_FIRST(&authctxt->keys)) { 1310 TAILQ_REMOVE(&authctxt->keys, id, next); 1311 if (id->key) 1312 sshkey_free(id->key); 1313 free(id->filename); 1314 free(id); 1315 } 1316} 1317 1318int 1319userauth_pubkey(Authctxt *authctxt) 1320{ 1321 Identity *id; 1322 int sent = 0; 1323 1324 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1325 if (id->tried++) 1326 return (0); 1327 /* move key to the end of the queue */ 1328 TAILQ_REMOVE(&authctxt->keys, id, next); 1329 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1330 /* 1331 * send a test message if we have the public key. for 1332 * encrypted keys we cannot do this and have to load the 1333 * private key instead 1334 */ 1335 if (id->key != NULL) { 1336 if (key_type_plain(id->key->type) == KEY_RSA && 1337 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1338 debug("Skipped %s key %s for RSA/MD5 server", 1339 key_type(id->key), id->filename); 1340 } else if (id->key->type != KEY_RSA1) { 1341 debug("Offering %s public key: %s", 1342 key_type(id->key), id->filename); 1343 sent = send_pubkey_test(authctxt, id); 1344 } 1345 } else { 1346 debug("Trying private key: %s", id->filename); 1347 id->key = load_identity_file(id->filename, 1348 id->userprovided); 1349 if (id->key != NULL) { 1350 id->isprivate = 1; 1351 if (key_type_plain(id->key->type) == KEY_RSA && 1352 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1353 debug("Skipped %s key %s for RSA/MD5 " 1354 "server", key_type(id->key), 1355 id->filename); 1356 } else { 1357 sent = sign_and_send_pubkey( 1358 authctxt, id); 1359 } 1360 key_free(id->key); 1361 id->key = NULL; 1362 } 1363 } 1364 if (sent) 1365 return (sent); 1366 } 1367 return (0); 1368} 1369 1370/* 1371 * Send userauth request message specifying keyboard-interactive method. 1372 */ 1373int 1374userauth_kbdint(Authctxt *authctxt) 1375{ 1376 static int attempt = 0; 1377 1378 if (attempt++ >= options.number_of_password_prompts) 1379 return 0; 1380 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1381 if (attempt > 1 && !authctxt->info_req_seen) { 1382 debug3("userauth_kbdint: disable: no info_req_seen"); 1383 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1384 return 0; 1385 } 1386 1387 debug2("userauth_kbdint"); 1388 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1389 packet_put_cstring(authctxt->server_user); 1390 packet_put_cstring(authctxt->service); 1391 packet_put_cstring(authctxt->method->name); 1392 packet_put_cstring(""); /* lang */ 1393 packet_put_cstring(options.kbd_interactive_devices ? 1394 options.kbd_interactive_devices : ""); 1395 packet_send(); 1396 1397 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1398 return 1; 1399} 1400 1401/* 1402 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1403 */ 1404int 1405input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1406{ 1407 Authctxt *authctxt = ctxt; 1408 char *name, *inst, *lang, *prompt, *response; 1409 u_int num_prompts, i; 1410 int echo = 0; 1411 1412 debug2("input_userauth_info_req"); 1413 1414 if (authctxt == NULL) 1415 fatal("input_userauth_info_req: no authentication context"); 1416 1417 authctxt->info_req_seen = 1; 1418 1419 name = packet_get_string(NULL); 1420 inst = packet_get_string(NULL); 1421 lang = packet_get_string(NULL); 1422 if (strlen(name) > 0) 1423 logit("%s", name); 1424 if (strlen(inst) > 0) 1425 logit("%s", inst); 1426 free(name); 1427 free(inst); 1428 free(lang); 1429 1430 num_prompts = packet_get_int(); 1431 /* 1432 * Begin to build info response packet based on prompts requested. 1433 * We commit to providing the correct number of responses, so if 1434 * further on we run into a problem that prevents this, we have to 1435 * be sure and clean this up and send a correct error response. 1436 */ 1437 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1438 packet_put_int(num_prompts); 1439 1440 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1441 for (i = 0; i < num_prompts; i++) { 1442 prompt = packet_get_string(NULL); 1443 echo = packet_get_char(); 1444 1445 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1446 1447 packet_put_cstring(response); 1448 explicit_bzero(response, strlen(response)); 1449 free(response); 1450 free(prompt); 1451 } 1452 packet_check_eom(); /* done with parsing incoming message. */ 1453 1454 packet_add_padding(64); 1455 packet_send(); 1456 return 0; 1457} 1458 1459static int 1460ssh_keysign(struct sshkey *key, u_char **sigp, size_t *lenp, 1461 const u_char *data, size_t datalen) 1462{ 1463 struct sshbuf *b; 1464 struct stat st; 1465 pid_t pid; 1466 int i, r, to[2], from[2], status, sock = packet_get_connection_in(); 1467 u_char rversion = 0, version = 2; 1468 void (*osigchld)(int); 1469 1470 *sigp = NULL; 1471 *lenp = 0; 1472 1473 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1474 error("%s: not installed: %s", __func__, strerror(errno)); 1475 return -1; 1476 } 1477 if (fflush(stdout) != 0) { 1478 error("%s: fflush: %s", __func__, strerror(errno)); 1479 return -1; 1480 } 1481 if (pipe(to) < 0) { 1482 error("%s: pipe: %s", __func__, strerror(errno)); 1483 return -1; 1484 } 1485 if (pipe(from) < 0) { 1486 error("%s: pipe: %s", __func__, strerror(errno)); 1487 return -1; 1488 } 1489 if ((pid = fork()) < 0) { 1490 error("%s: fork: %s", __func__, strerror(errno)); 1491 return -1; 1492 } 1493 osigchld = signal(SIGCHLD, SIG_DFL); 1494 if (pid == 0) { 1495 /* keep the socket on exec */ 1496 fcntl(sock, F_SETFD, 0); 1497 permanently_drop_suid(getuid()); 1498 close(from[0]); 1499 if (dup2(from[1], STDOUT_FILENO) < 0) 1500 fatal("%s: dup2: %s", __func__, strerror(errno)); 1501 close(to[1]); 1502 if (dup2(to[0], STDIN_FILENO) < 0) 1503 fatal("%s: dup2: %s", __func__, strerror(errno)); 1504 close(from[1]); 1505 close(to[0]); 1506 /* Close everything but stdio and the socket */ 1507 for (i = STDERR_FILENO + 1; i < sock; i++) 1508 close(i); 1509 closefrom(sock + 1); 1510 debug3("%s: [child] pid=%ld, exec %s", 1511 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1512 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1513 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1514 strerror(errno)); 1515 } 1516 close(from[1]); 1517 close(to[0]); 1518 1519 if ((b = sshbuf_new()) == NULL) 1520 fatal("%s: sshbuf_new failed", __func__); 1521 /* send # of sock, data to be signed */ 1522 if ((r = sshbuf_put_u32(b, sock) != 0) || 1523 (r = sshbuf_put_string(b, data, datalen)) != 0) 1524 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1525 if (ssh_msg_send(to[1], version, b) == -1) 1526 fatal("%s: couldn't send request", __func__); 1527 sshbuf_reset(b); 1528 r = ssh_msg_recv(from[0], b); 1529 close(from[0]); 1530 close(to[1]); 1531 if (r < 0) { 1532 error("%s: no reply", __func__); 1533 goto fail; 1534 } 1535 1536 errno = 0; 1537 while (waitpid(pid, &status, 0) < 0) { 1538 if (errno != EINTR) { 1539 error("%s: waitpid %ld: %s", 1540 __func__, (long)pid, strerror(errno)); 1541 goto fail; 1542 } 1543 } 1544 if (!WIFEXITED(status)) { 1545 error("%s: exited abnormally", __func__); 1546 goto fail; 1547 } 1548 if (WEXITSTATUS(status) != 0) { 1549 error("%s: exited with status %d", 1550 __func__, WEXITSTATUS(status)); 1551 goto fail; 1552 } 1553 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 1554 error("%s: buffer error: %s", __func__, ssh_err(r)); 1555 goto fail; 1556 } 1557 if (rversion != version) { 1558 error("%s: bad version", __func__); 1559 goto fail; 1560 } 1561 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 1562 error("%s: buffer error: %s", __func__, ssh_err(r)); 1563 fail: 1564 signal(SIGCHLD, osigchld); 1565 sshbuf_free(b); 1566 return -1; 1567 } 1568 signal(SIGCHLD, osigchld); 1569 sshbuf_free(b); 1570 1571 return 0; 1572} 1573 1574int 1575userauth_hostbased(Authctxt *authctxt) 1576{ 1577 struct ssh *ssh = active_state; 1578 struct sshkey *private = NULL; 1579 struct sshbuf *b = NULL; 1580 const char *service; 1581 u_char *sig = NULL, *keyblob = NULL; 1582 char *fp = NULL, *chost = NULL, *lname = NULL; 1583 size_t siglen = 0, keylen = 0; 1584 int i, r, success = 0; 1585 1586 if (authctxt->ktypes == NULL) { 1587 authctxt->oktypes = xstrdup(options.hostbased_key_types); 1588 authctxt->ktypes = authctxt->oktypes; 1589 } 1590 1591 /* 1592 * Work through each listed type pattern in HostbasedKeyTypes, 1593 * trying each hostkey that matches the type in turn. 1594 */ 1595 for (;;) { 1596 if (authctxt->active_ktype == NULL) 1597 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 1598 if (authctxt->active_ktype == NULL || 1599 *authctxt->active_ktype == '\0') 1600 break; 1601 debug3("%s: trying key type %s", __func__, 1602 authctxt->active_ktype); 1603 1604 /* check for a useful key */ 1605 private = NULL; 1606 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 1607 if (authctxt->sensitive->keys[i] == NULL || 1608 authctxt->sensitive->keys[i]->type == KEY_RSA1 || 1609 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 1610 continue; 1611 if (match_pattern_list( 1612 sshkey_ssh_name(authctxt->sensitive->keys[i]), 1613 authctxt->active_ktype, 1614 strlen(authctxt->active_ktype), 0) != 1) 1615 continue; 1616 /* we take and free the key */ 1617 private = authctxt->sensitive->keys[i]; 1618 authctxt->sensitive->keys[i] = NULL; 1619 break; 1620 } 1621 /* Found one */ 1622 if (private != NULL) 1623 break; 1624 /* No more keys of this type; advance */ 1625 authctxt->active_ktype = NULL; 1626 } 1627 if (private == NULL) { 1628 free(authctxt->oktypes); 1629 authctxt->oktypes = authctxt->ktypes = NULL; 1630 authctxt->active_ktype = NULL; 1631 debug("No more client hostkeys for hostbased authentication."); 1632 goto out; 1633 } 1634 1635 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 1636 SSH_FP_DEFAULT)) == NULL) { 1637 error("%s: sshkey_fingerprint failed", __func__); 1638 goto out; 1639 } 1640 debug("%s: trying hostkey %s %s", 1641 __func__, sshkey_ssh_name(private), fp); 1642 1643 /* figure out a name for the client host */ 1644 if ((lname = get_local_name(packet_get_connection_in())) == NULL) { 1645 error("%s: cannot get local ipaddr/name", __func__); 1646 goto out; 1647 } 1648 1649 /* XXX sshbuf_put_stringf? */ 1650 xasprintf(&chost, "%s.", lname); 1651 debug2("%s: chost %s", __func__, chost); 1652 1653 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1654 authctxt->service; 1655 1656 /* construct data */ 1657 if ((b = sshbuf_new()) == NULL) { 1658 error("%s: sshbuf_new failed", __func__); 1659 goto out; 1660 } 1661 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 1662 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 1663 goto out; 1664 } 1665 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 1666 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1667 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1668 (r = sshbuf_put_cstring(b, service)) != 0 || 1669 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1670 (r = sshbuf_put_cstring(b, key_ssh_name(private))) != 0 || 1671 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 1672 (r = sshbuf_put_cstring(b, chost)) != 0 || 1673 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 1674 error("%s: buffer error: %s", __func__, ssh_err(r)); 1675 goto out; 1676 } 1677 1678#ifdef DEBUG_PK 1679 sshbuf_dump(b, stderr); 1680#endif 1681 if (authctxt->sensitive->external_keysign) 1682 r = ssh_keysign(private, &sig, &siglen, 1683 sshbuf_ptr(b), sshbuf_len(b)); 1684 else if ((r = sshkey_sign(private, &sig, &siglen, 1685 sshbuf_ptr(b), sshbuf_len(b), datafellows)) != 0) 1686 debug("%s: sshkey_sign: %s", __func__, ssh_err(r)); 1687 if (r != 0) { 1688 error("sign using hostkey %s %s failed", 1689 sshkey_ssh_name(private), fp); 1690 goto out; 1691 } 1692 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1693 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1694 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1695 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1696 (r = sshpkt_put_cstring(ssh, key_ssh_name(private))) != 0 || 1697 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 1698 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 1699 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 1700 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 1701 (r = sshpkt_send(ssh)) != 0) { 1702 error("%s: packet error: %s", __func__, ssh_err(r)); 1703 goto out; 1704 } 1705 success = 1; 1706 1707 out: 1708 if (sig != NULL) { 1709 explicit_bzero(sig, siglen); 1710 free(sig); 1711 } 1712 free(keyblob); 1713 free(lname); 1714 free(fp); 1715 free(chost); 1716 sshkey_free(private); 1717 sshbuf_free(b); 1718 1719 return success; 1720} 1721 1722/* find auth method */ 1723 1724/* 1725 * given auth method name, if configurable options permit this method fill 1726 * in auth_ident field and return true, otherwise return false. 1727 */ 1728static int 1729authmethod_is_enabled(Authmethod *method) 1730{ 1731 if (method == NULL) 1732 return 0; 1733 /* return false if options indicate this method is disabled */ 1734 if (method->enabled == NULL || *method->enabled == 0) 1735 return 0; 1736 /* return false if batch mode is enabled but method needs interactive mode */ 1737 if (method->batch_flag != NULL && *method->batch_flag != 0) 1738 return 0; 1739 return 1; 1740} 1741 1742static Authmethod * 1743authmethod_lookup(const char *name) 1744{ 1745 Authmethod *method = NULL; 1746 if (name != NULL) 1747 for (method = authmethods; method->name != NULL; method++) 1748 if (strcmp(name, method->name) == 0) 1749 return method; 1750 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1751 return NULL; 1752} 1753 1754/* XXX internal state */ 1755static Authmethod *current = NULL; 1756static char *supported = NULL; 1757static char *preferred = NULL; 1758 1759/* 1760 * Given the authentication method list sent by the server, return the 1761 * next method we should try. If the server initially sends a nil list, 1762 * use a built-in default list. 1763 */ 1764static Authmethod * 1765authmethod_get(char *authlist) 1766{ 1767 char *name = NULL; 1768 u_int next; 1769 1770 /* Use a suitable default if we're passed a nil list. */ 1771 if (authlist == NULL || strlen(authlist) == 0) 1772 authlist = options.preferred_authentications; 1773 1774 if (supported == NULL || strcmp(authlist, supported) != 0) { 1775 debug3("start over, passed a different list %s", authlist); 1776 free(supported); 1777 supported = xstrdup(authlist); 1778 preferred = options.preferred_authentications; 1779 debug3("preferred %s", preferred); 1780 current = NULL; 1781 } else if (current != NULL && authmethod_is_enabled(current)) 1782 return current; 1783 1784 for (;;) { 1785 if ((name = match_list(preferred, supported, &next)) == NULL) { 1786 debug("No more authentication methods to try."); 1787 current = NULL; 1788 return NULL; 1789 } 1790 preferred += next; 1791 debug3("authmethod_lookup %s", name); 1792 debug3("remaining preferred: %s", preferred); 1793 if ((current = authmethod_lookup(name)) != NULL && 1794 authmethod_is_enabled(current)) { 1795 debug3("authmethod_is_enabled %s", name); 1796 debug("Next authentication method: %s", name); 1797 free(name); 1798 return current; 1799 } 1800 free(name); 1801 } 1802} 1803 1804static char * 1805authmethods_get(void) 1806{ 1807 Authmethod *method = NULL; 1808 Buffer b; 1809 char *list; 1810 1811 buffer_init(&b); 1812 for (method = authmethods; method->name != NULL; method++) { 1813 if (authmethod_is_enabled(method)) { 1814 if (buffer_len(&b) > 0) 1815 buffer_append(&b, ",", 1); 1816 buffer_append(&b, method->name, strlen(method->name)); 1817 } 1818 } 1819 buffer_append(&b, "\0", 1); 1820 list = xstrdup(buffer_ptr(&b)); 1821 buffer_free(&b); 1822 return list; 1823} 1824 1825