sshconnect2.c revision 295367
1/* $OpenBSD: sshconnect2.c,v 1.226 2015/07/30 00:01:34 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 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal( 167 options.kex_algorithms); 168 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 169 compat_cipher_proposal(options.ciphers); 170 myproposal[PROPOSAL_ENC_ALGS_STOC] = 171 compat_cipher_proposal(options.ciphers); 172 if (options.compression) { 173 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 174 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 175 } else { 176 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 177 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 178 } 179 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 180 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 181 if (options.hostkeyalgorithms != NULL) { 182 if (kex_assemble_names(KEX_DEFAULT_PK_ALG, 183 &options.hostkeyalgorithms) != 0) 184 fatal("%s: kex_assemble_namelist", __func__); 185 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 186 compat_pkalg_proposal(options.hostkeyalgorithms); 187 } else { 188 /* Enforce default */ 189 options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG); 190 /* Prefer algorithms that we already have keys for */ 191 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 192 compat_pkalg_proposal( 193 order_hostkeyalgs(host, hostaddr, port)); 194 } 195 196 if (options.rekey_limit || options.rekey_interval) 197 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 198 (time_t)options.rekey_interval); 199 200 /* start key exchange */ 201 if ((r = kex_setup(active_state, myproposal)) != 0) 202 fatal("kex_setup: %s", ssh_err(r)); 203 kex = active_state->kex; 204#ifdef WITH_OPENSSL 205 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 206 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 207 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 208 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 209# ifdef OPENSSL_HAS_ECC 210 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 211# endif 212#endif 213 kex->kex[KEX_C25519_SHA256] = kexc25519_client; 214 kex->client_version_string=client_version_string; 215 kex->server_version_string=server_version_string; 216 kex->verify_host_key=&verify_host_key_callback; 217 218 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); 219 220 if (options.use_roaming && !kex->roaming) { 221 debug("Roaming not allowed by server"); 222 options.use_roaming = 0; 223 } 224 225 session_id2 = kex->session_id; 226 session_id2_len = kex->session_id_len; 227 228#ifdef DEBUG_KEXDH 229 /* send 1st encrypted/maced/compressed message */ 230 packet_start(SSH2_MSG_IGNORE); 231 packet_put_cstring("markus"); 232 packet_send(); 233 packet_write_wait(); 234#endif 235} 236 237/* 238 * Authenticate user 239 */ 240 241typedef struct cauthctxt Authctxt; 242typedef struct cauthmethod Authmethod; 243typedef struct identity Identity; 244typedef struct idlist Idlist; 245 246struct identity { 247 TAILQ_ENTRY(identity) next; 248 int agent_fd; /* >=0 if agent supports key */ 249 struct sshkey *key; /* public/private key */ 250 char *filename; /* comment for agent-only keys */ 251 int tried; 252 int isprivate; /* key points to the private key */ 253 int userprovided; 254}; 255TAILQ_HEAD(idlist, identity); 256 257struct cauthctxt { 258 const char *server_user; 259 const char *local_user; 260 const char *host; 261 const char *service; 262 struct cauthmethod *method; 263 sig_atomic_t success; 264 char *authlist; 265 int attempt; 266 /* pubkey */ 267 struct idlist keys; 268 int agent_fd; 269 /* hostbased */ 270 Sensitive *sensitive; 271 char *oktypes, *ktypes; 272 const char *active_ktype; 273 /* kbd-interactive */ 274 int info_req_seen; 275 /* generic */ 276 void *methoddata; 277}; 278 279struct cauthmethod { 280 char *name; /* string to compare against server's list */ 281 int (*userauth)(Authctxt *authctxt); 282 void (*cleanup)(Authctxt *authctxt); 283 int *enabled; /* flag in option struct that enables method */ 284 int *batch_flag; /* flag in option struct that disables method */ 285}; 286 287int input_userauth_success(int, u_int32_t, void *); 288int input_userauth_success_unexpected(int, u_int32_t, void *); 289int input_userauth_failure(int, u_int32_t, void *); 290int input_userauth_banner(int, u_int32_t, void *); 291int input_userauth_error(int, u_int32_t, void *); 292int input_userauth_info_req(int, u_int32_t, void *); 293int input_userauth_pk_ok(int, u_int32_t, void *); 294int input_userauth_passwd_changereq(int, u_int32_t, void *); 295 296int userauth_none(Authctxt *); 297int userauth_pubkey(Authctxt *); 298int userauth_passwd(Authctxt *); 299int userauth_kbdint(Authctxt *); 300int userauth_hostbased(Authctxt *); 301 302#ifdef GSSAPI 303int userauth_gssapi(Authctxt *authctxt); 304int input_gssapi_response(int type, u_int32_t, void *); 305int input_gssapi_token(int type, u_int32_t, void *); 306int input_gssapi_hash(int type, u_int32_t, void *); 307int input_gssapi_error(int, u_int32_t, void *); 308int input_gssapi_errtok(int, u_int32_t, void *); 309#endif 310 311void userauth(Authctxt *, char *); 312 313static int sign_and_send_pubkey(Authctxt *, Identity *); 314static void pubkey_prepare(Authctxt *); 315static void pubkey_cleanup(Authctxt *); 316static Key *load_identity_file(char *, int); 317 318static Authmethod *authmethod_get(char *authlist); 319static Authmethod *authmethod_lookup(const char *name); 320static char *authmethods_get(void); 321 322Authmethod authmethods[] = { 323#ifdef GSSAPI 324 {"gssapi-with-mic", 325 userauth_gssapi, 326 NULL, 327 &options.gss_authentication, 328 NULL}, 329#endif 330 {"hostbased", 331 userauth_hostbased, 332 NULL, 333 &options.hostbased_authentication, 334 NULL}, 335 {"publickey", 336 userauth_pubkey, 337 NULL, 338 &options.pubkey_authentication, 339 NULL}, 340 {"keyboard-interactive", 341 userauth_kbdint, 342 NULL, 343 &options.kbd_interactive_authentication, 344 &options.batch_mode}, 345 {"password", 346 userauth_passwd, 347 NULL, 348 &options.password_authentication, 349 &options.batch_mode}, 350 {"none", 351 userauth_none, 352 NULL, 353 NULL, 354 NULL}, 355 {NULL, NULL, NULL, NULL, NULL} 356}; 357 358void 359ssh_userauth2(const char *local_user, const char *server_user, char *host, 360 Sensitive *sensitive) 361{ 362 Authctxt authctxt; 363 int type; 364 365 if (options.challenge_response_authentication) 366 options.kbd_interactive_authentication = 1; 367 368 packet_start(SSH2_MSG_SERVICE_REQUEST); 369 packet_put_cstring("ssh-userauth"); 370 packet_send(); 371 debug("SSH2_MSG_SERVICE_REQUEST sent"); 372 packet_write_wait(); 373 type = packet_read(); 374 if (type != SSH2_MSG_SERVICE_ACCEPT) 375 fatal("Server denied authentication request: %d", type); 376 if (packet_remaining() > 0) { 377 char *reply = packet_get_string(NULL); 378 debug2("service_accept: %s", reply); 379 free(reply); 380 } else { 381 debug2("buggy server: service_accept w/o service"); 382 } 383 packet_check_eom(); 384 debug("SSH2_MSG_SERVICE_ACCEPT received"); 385 386 if (options.preferred_authentications == NULL) 387 options.preferred_authentications = authmethods_get(); 388 389 /* setup authentication context */ 390 memset(&authctxt, 0, sizeof(authctxt)); 391 pubkey_prepare(&authctxt); 392 authctxt.server_user = server_user; 393 authctxt.local_user = local_user; 394 authctxt.host = host; 395 authctxt.service = "ssh-connection"; /* service name */ 396 authctxt.success = 0; 397 authctxt.method = authmethod_lookup("none"); 398 authctxt.authlist = NULL; 399 authctxt.methoddata = NULL; 400 authctxt.sensitive = sensitive; 401 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 402 authctxt.info_req_seen = 0; 403 authctxt.agent_fd = -1; 404 if (authctxt.method == NULL) 405 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 406 407 /* initial userauth request */ 408 userauth_none(&authctxt); 409 410 dispatch_init(&input_userauth_error); 411 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 412 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 413 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 414 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 415 416 pubkey_cleanup(&authctxt); 417 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 418 419 debug("Authentication succeeded (%s).", authctxt.method->name); 420} 421 422void 423userauth(Authctxt *authctxt, char *authlist) 424{ 425 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 426 authctxt->method->cleanup(authctxt); 427 428 free(authctxt->methoddata); 429 authctxt->methoddata = NULL; 430 if (authlist == NULL) { 431 authlist = authctxt->authlist; 432 } else { 433 free(authctxt->authlist); 434 authctxt->authlist = authlist; 435 } 436 for (;;) { 437 Authmethod *method = authmethod_get(authlist); 438 if (method == NULL) 439 fatal("Permission denied (%s).", authlist); 440 authctxt->method = method; 441 442 /* reset the per method handler */ 443 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 444 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 445 446 /* and try new method */ 447 if (method->userauth(authctxt) != 0) { 448 debug2("we sent a %s packet, wait for reply", method->name); 449 break; 450 } else { 451 debug2("we did not send a packet, disable method"); 452 method->enabled = NULL; 453 } 454 } 455} 456 457/* ARGSUSED */ 458int 459input_userauth_error(int type, u_int32_t seq, void *ctxt) 460{ 461 fatal("input_userauth_error: bad message during authentication: " 462 "type %d", type); 463 return 0; 464} 465 466/* ARGSUSED */ 467int 468input_userauth_banner(int type, u_int32_t seq, void *ctxt) 469{ 470 char *msg, *raw, *lang; 471 u_int len; 472 473 debug3("input_userauth_banner"); 474 raw = packet_get_string(&len); 475 lang = packet_get_string(NULL); 476 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 477 if (len > 65536) 478 len = 65536; 479 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 480 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 481 fprintf(stderr, "%s", msg); 482 free(msg); 483 } 484 free(raw); 485 free(lang); 486 return 0; 487} 488 489/* ARGSUSED */ 490int 491input_userauth_success(int type, u_int32_t seq, void *ctxt) 492{ 493 Authctxt *authctxt = ctxt; 494 495 if (authctxt == NULL) 496 fatal("input_userauth_success: no authentication context"); 497 free(authctxt->authlist); 498 authctxt->authlist = NULL; 499 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 500 authctxt->method->cleanup(authctxt); 501 free(authctxt->methoddata); 502 authctxt->methoddata = NULL; 503 authctxt->success = 1; /* break out */ 504 return 0; 505} 506 507int 508input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 509{ 510 Authctxt *authctxt = ctxt; 511 512 if (authctxt == NULL) 513 fatal("%s: no authentication context", __func__); 514 515 fatal("Unexpected authentication success during %s.", 516 authctxt->method->name); 517 return 0; 518} 519 520/* ARGSUSED */ 521int 522input_userauth_failure(int type, u_int32_t seq, void *ctxt) 523{ 524 Authctxt *authctxt = ctxt; 525 char *authlist = NULL; 526 int partial; 527 528 if (authctxt == NULL) 529 fatal("input_userauth_failure: no authentication context"); 530 531 authlist = packet_get_string(NULL); 532 partial = packet_get_char(); 533 packet_check_eom(); 534 535 if (partial != 0) { 536 logit("Authenticated with partial success."); 537 /* reset state */ 538 pubkey_cleanup(authctxt); 539 pubkey_prepare(authctxt); 540 } 541 debug("Authentications that can continue: %s", authlist); 542 543 userauth(authctxt, authlist); 544 return 0; 545} 546 547/* ARGSUSED */ 548int 549input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 550{ 551 Authctxt *authctxt = ctxt; 552 Key *key = NULL; 553 Identity *id = NULL; 554 Buffer b; 555 int pktype, sent = 0; 556 u_int alen, blen; 557 char *pkalg, *fp; 558 u_char *pkblob; 559 560 if (authctxt == NULL) 561 fatal("input_userauth_pk_ok: no authentication context"); 562 if (datafellows & SSH_BUG_PKOK) { 563 /* this is similar to SSH_BUG_PKAUTH */ 564 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 565 pkblob = packet_get_string(&blen); 566 buffer_init(&b); 567 buffer_append(&b, pkblob, blen); 568 pkalg = buffer_get_string(&b, &alen); 569 buffer_free(&b); 570 } else { 571 pkalg = packet_get_string(&alen); 572 pkblob = packet_get_string(&blen); 573 } 574 packet_check_eom(); 575 576 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 577 578 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 579 debug("unknown pkalg %s", pkalg); 580 goto done; 581 } 582 if ((key = key_from_blob(pkblob, blen)) == NULL) { 583 debug("no key from blob. pkalg %s", pkalg); 584 goto done; 585 } 586 if (key->type != pktype) { 587 error("input_userauth_pk_ok: type mismatch " 588 "for decoded key (received %d, expected %d)", 589 key->type, pktype); 590 goto done; 591 } 592 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 593 SSH_FP_DEFAULT)) == NULL) 594 goto done; 595 debug2("input_userauth_pk_ok: fp %s", fp); 596 free(fp); 597 598 /* 599 * search keys in the reverse order, because last candidate has been 600 * moved to the end of the queue. this also avoids confusion by 601 * duplicate keys 602 */ 603 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 604 if (key_equal(key, id->key)) { 605 sent = sign_and_send_pubkey(authctxt, id); 606 break; 607 } 608 } 609done: 610 if (key != NULL) 611 key_free(key); 612 free(pkalg); 613 free(pkblob); 614 615 /* try another method if we did not send a packet */ 616 if (sent == 0) 617 userauth(authctxt, NULL); 618 return 0; 619} 620 621#ifdef GSSAPI 622int 623userauth_gssapi(Authctxt *authctxt) 624{ 625 Gssctxt *gssctxt = NULL; 626 static gss_OID_set gss_supported = NULL; 627 static u_int mech = 0; 628 OM_uint32 min; 629 int ok = 0; 630 631 /* Try one GSSAPI method at a time, rather than sending them all at 632 * once. */ 633 634 if (gss_supported == NULL) 635 gss_indicate_mechs(&min, &gss_supported); 636 637 /* Check to see if the mechanism is usable before we offer it */ 638 while (mech < gss_supported->count && !ok) { 639 /* My DER encoding requires length<128 */ 640 if (gss_supported->elements[mech].length < 128 && 641 ssh_gssapi_check_mechanism(&gssctxt, 642 &gss_supported->elements[mech], authctxt->host)) { 643 ok = 1; /* Mechanism works */ 644 } else { 645 mech++; 646 } 647 } 648 649 if (!ok) 650 return 0; 651 652 authctxt->methoddata=(void *)gssctxt; 653 654 packet_start(SSH2_MSG_USERAUTH_REQUEST); 655 packet_put_cstring(authctxt->server_user); 656 packet_put_cstring(authctxt->service); 657 packet_put_cstring(authctxt->method->name); 658 659 packet_put_int(1); 660 661 packet_put_int((gss_supported->elements[mech].length) + 2); 662 packet_put_char(SSH_GSS_OIDTYPE); 663 packet_put_char(gss_supported->elements[mech].length); 664 packet_put_raw(gss_supported->elements[mech].elements, 665 gss_supported->elements[mech].length); 666 667 packet_send(); 668 669 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 670 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 671 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 672 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 673 674 mech++; /* Move along to next candidate */ 675 676 return 1; 677} 678 679static OM_uint32 680process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 681{ 682 Authctxt *authctxt = ctxt; 683 Gssctxt *gssctxt = authctxt->methoddata; 684 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 685 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 686 gss_buffer_desc gssbuf; 687 OM_uint32 status, ms, flags; 688 Buffer b; 689 690 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 691 recv_tok, &send_tok, &flags); 692 693 if (send_tok.length > 0) { 694 if (GSS_ERROR(status)) 695 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 696 else 697 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 698 699 packet_put_string(send_tok.value, send_tok.length); 700 packet_send(); 701 gss_release_buffer(&ms, &send_tok); 702 } 703 704 if (status == GSS_S_COMPLETE) { 705 /* send either complete or MIC, depending on mechanism */ 706 if (!(flags & GSS_C_INTEG_FLAG)) { 707 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 708 packet_send(); 709 } else { 710 ssh_gssapi_buildmic(&b, authctxt->server_user, 711 authctxt->service, "gssapi-with-mic"); 712 713 gssbuf.value = buffer_ptr(&b); 714 gssbuf.length = buffer_len(&b); 715 716 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 717 718 if (!GSS_ERROR(status)) { 719 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 720 packet_put_string(mic.value, mic.length); 721 722 packet_send(); 723 } 724 725 buffer_free(&b); 726 gss_release_buffer(&ms, &mic); 727 } 728 } 729 730 return status; 731} 732 733/* ARGSUSED */ 734int 735input_gssapi_response(int type, u_int32_t plen, void *ctxt) 736{ 737 Authctxt *authctxt = ctxt; 738 Gssctxt *gssctxt; 739 int oidlen; 740 char *oidv; 741 742 if (authctxt == NULL) 743 fatal("input_gssapi_response: no authentication context"); 744 gssctxt = authctxt->methoddata; 745 746 /* Setup our OID */ 747 oidv = packet_get_string(&oidlen); 748 749 if (oidlen <= 2 || 750 oidv[0] != SSH_GSS_OIDTYPE || 751 oidv[1] != oidlen - 2) { 752 free(oidv); 753 debug("Badly encoded mechanism OID received"); 754 userauth(authctxt, NULL); 755 return 0; 756 } 757 758 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 759 fatal("Server returned different OID than expected"); 760 761 packet_check_eom(); 762 763 free(oidv); 764 765 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 766 /* Start again with next method on list */ 767 debug("Trying to start again"); 768 userauth(authctxt, NULL); 769 return 0; 770 } 771 return 0; 772} 773 774/* ARGSUSED */ 775int 776input_gssapi_token(int type, u_int32_t plen, void *ctxt) 777{ 778 Authctxt *authctxt = ctxt; 779 gss_buffer_desc recv_tok; 780 OM_uint32 status; 781 u_int slen; 782 783 if (authctxt == NULL) 784 fatal("input_gssapi_response: no authentication context"); 785 786 recv_tok.value = packet_get_string(&slen); 787 recv_tok.length = slen; /* safe typecast */ 788 789 packet_check_eom(); 790 791 status = process_gssapi_token(ctxt, &recv_tok); 792 793 free(recv_tok.value); 794 795 if (GSS_ERROR(status)) { 796 /* Start again with the next method in the list */ 797 userauth(authctxt, NULL); 798 return 0; 799 } 800 return 0; 801} 802 803/* ARGSUSED */ 804int 805input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 806{ 807 Authctxt *authctxt = ctxt; 808 Gssctxt *gssctxt; 809 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 810 gss_buffer_desc recv_tok; 811 OM_uint32 ms; 812 u_int len; 813 814 if (authctxt == NULL) 815 fatal("input_gssapi_response: no authentication context"); 816 gssctxt = authctxt->methoddata; 817 818 recv_tok.value = packet_get_string(&len); 819 recv_tok.length = len; 820 821 packet_check_eom(); 822 823 /* Stick it into GSSAPI and see what it says */ 824 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 825 &recv_tok, &send_tok, NULL); 826 827 free(recv_tok.value); 828 gss_release_buffer(&ms, &send_tok); 829 830 /* Server will be returning a failed packet after this one */ 831 return 0; 832} 833 834/* ARGSUSED */ 835int 836input_gssapi_error(int type, u_int32_t plen, void *ctxt) 837{ 838 char *msg; 839 char *lang; 840 841 /* maj */(void)packet_get_int(); 842 /* min */(void)packet_get_int(); 843 msg=packet_get_string(NULL); 844 lang=packet_get_string(NULL); 845 846 packet_check_eom(); 847 848 debug("Server GSSAPI Error:\n%s", msg); 849 free(msg); 850 free(lang); 851 return 0; 852} 853#endif /* GSSAPI */ 854 855int 856userauth_none(Authctxt *authctxt) 857{ 858 /* initial userauth request */ 859 packet_start(SSH2_MSG_USERAUTH_REQUEST); 860 packet_put_cstring(authctxt->server_user); 861 packet_put_cstring(authctxt->service); 862 packet_put_cstring(authctxt->method->name); 863 packet_send(); 864 return 1; 865} 866 867int 868userauth_passwd(Authctxt *authctxt) 869{ 870 static int attempt = 0; 871 char prompt[150]; 872 char *password; 873 const char *host = options.host_key_alias ? options.host_key_alias : 874 authctxt->host; 875 876 if (attempt++ >= options.number_of_password_prompts) 877 return 0; 878 879 if (attempt != 1) 880 error("Permission denied, please try again."); 881 882 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 883 authctxt->server_user, host); 884 password = read_passphrase(prompt, 0); 885 packet_start(SSH2_MSG_USERAUTH_REQUEST); 886 packet_put_cstring(authctxt->server_user); 887 packet_put_cstring(authctxt->service); 888 packet_put_cstring(authctxt->method->name); 889 packet_put_char(0); 890 packet_put_cstring(password); 891 explicit_bzero(password, strlen(password)); 892 free(password); 893 packet_add_padding(64); 894 packet_send(); 895 896 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 897 &input_userauth_passwd_changereq); 898 899 return 1; 900} 901 902/* 903 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 904 */ 905/* ARGSUSED */ 906int 907input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 908{ 909 Authctxt *authctxt = ctxt; 910 char *info, *lang, *password = NULL, *retype = NULL; 911 char prompt[150]; 912 const char *host = options.host_key_alias ? options.host_key_alias : 913 authctxt->host; 914 915 debug2("input_userauth_passwd_changereq"); 916 917 if (authctxt == NULL) 918 fatal("input_userauth_passwd_changereq: " 919 "no authentication context"); 920 921 info = packet_get_string(NULL); 922 lang = packet_get_string(NULL); 923 if (strlen(info) > 0) 924 logit("%s", info); 925 free(info); 926 free(lang); 927 packet_start(SSH2_MSG_USERAUTH_REQUEST); 928 packet_put_cstring(authctxt->server_user); 929 packet_put_cstring(authctxt->service); 930 packet_put_cstring(authctxt->method->name); 931 packet_put_char(1); /* additional info */ 932 snprintf(prompt, sizeof(prompt), 933 "Enter %.30s@%.128s's old password: ", 934 authctxt->server_user, host); 935 password = read_passphrase(prompt, 0); 936 packet_put_cstring(password); 937 explicit_bzero(password, strlen(password)); 938 free(password); 939 password = NULL; 940 while (password == NULL) { 941 snprintf(prompt, sizeof(prompt), 942 "Enter %.30s@%.128s's new password: ", 943 authctxt->server_user, host); 944 password = read_passphrase(prompt, RP_ALLOW_EOF); 945 if (password == NULL) { 946 /* bail out */ 947 return 0; 948 } 949 snprintf(prompt, sizeof(prompt), 950 "Retype %.30s@%.128s's new password: ", 951 authctxt->server_user, host); 952 retype = read_passphrase(prompt, 0); 953 if (strcmp(password, retype) != 0) { 954 explicit_bzero(password, strlen(password)); 955 free(password); 956 logit("Mismatch; try again, EOF to quit."); 957 password = NULL; 958 } 959 explicit_bzero(retype, strlen(retype)); 960 free(retype); 961 } 962 packet_put_cstring(password); 963 explicit_bzero(password, strlen(password)); 964 free(password); 965 packet_add_padding(64); 966 packet_send(); 967 968 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 969 &input_userauth_passwd_changereq); 970 return 0; 971} 972 973static int 974identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 975 const u_char *data, size_t datalen, u_int compat) 976{ 977 Key *prv; 978 int ret; 979 980 /* the agent supports this key */ 981 if (id->agent_fd) 982 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 983 data, datalen, compat); 984 985 /* 986 * we have already loaded the private key or 987 * the private key is stored in external hardware 988 */ 989 if (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT)) 990 return (sshkey_sign(id->key, sigp, lenp, data, datalen, 991 compat)); 992 /* load the private key from the file */ 993 if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL) 994 return (-1); /* XXX return decent error code */ 995 ret = sshkey_sign(prv, sigp, lenp, data, datalen, compat); 996 sshkey_free(prv); 997 return (ret); 998} 999 1000static int 1001sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1002{ 1003 Buffer b; 1004 u_char *blob, *signature; 1005 u_int bloblen; 1006 size_t slen; 1007 u_int skip = 0; 1008 int ret = -1; 1009 int have_sig = 1; 1010 char *fp; 1011 1012 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1013 SSH_FP_DEFAULT)) == NULL) 1014 return 0; 1015 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1016 free(fp); 1017 1018 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1019 /* we cannot handle this key */ 1020 debug3("sign_and_send_pubkey: cannot handle key"); 1021 return 0; 1022 } 1023 /* data to be signed */ 1024 buffer_init(&b); 1025 if (datafellows & SSH_OLD_SESSIONID) { 1026 buffer_append(&b, session_id2, session_id2_len); 1027 skip = session_id2_len; 1028 } else { 1029 buffer_put_string(&b, session_id2, session_id2_len); 1030 skip = buffer_len(&b); 1031 } 1032 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1033 buffer_put_cstring(&b, authctxt->server_user); 1034 buffer_put_cstring(&b, 1035 datafellows & SSH_BUG_PKSERVICE ? 1036 "ssh-userauth" : 1037 authctxt->service); 1038 if (datafellows & SSH_BUG_PKAUTH) { 1039 buffer_put_char(&b, have_sig); 1040 } else { 1041 buffer_put_cstring(&b, authctxt->method->name); 1042 buffer_put_char(&b, have_sig); 1043 buffer_put_cstring(&b, key_ssh_name(id->key)); 1044 } 1045 buffer_put_string(&b, blob, bloblen); 1046 1047 /* generate signature */ 1048 ret = identity_sign(id, &signature, &slen, 1049 buffer_ptr(&b), buffer_len(&b), datafellows); 1050 if (ret != 0) { 1051 free(blob); 1052 buffer_free(&b); 1053 return 0; 1054 } 1055#ifdef DEBUG_PK 1056 buffer_dump(&b); 1057#endif 1058 if (datafellows & SSH_BUG_PKSERVICE) { 1059 buffer_clear(&b); 1060 buffer_append(&b, session_id2, session_id2_len); 1061 skip = session_id2_len; 1062 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1063 buffer_put_cstring(&b, authctxt->server_user); 1064 buffer_put_cstring(&b, authctxt->service); 1065 buffer_put_cstring(&b, authctxt->method->name); 1066 buffer_put_char(&b, have_sig); 1067 if (!(datafellows & SSH_BUG_PKAUTH)) 1068 buffer_put_cstring(&b, key_ssh_name(id->key)); 1069 buffer_put_string(&b, blob, bloblen); 1070 } 1071 free(blob); 1072 1073 /* append signature */ 1074 buffer_put_string(&b, signature, slen); 1075 free(signature); 1076 1077 /* skip session id and packet type */ 1078 if (buffer_len(&b) < skip + 1) 1079 fatal("userauth_pubkey: internal error"); 1080 buffer_consume(&b, skip + 1); 1081 1082 /* put remaining data from buffer into packet */ 1083 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1084 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1085 buffer_free(&b); 1086 packet_send(); 1087 1088 return 1; 1089} 1090 1091static int 1092send_pubkey_test(Authctxt *authctxt, Identity *id) 1093{ 1094 u_char *blob; 1095 u_int bloblen, have_sig = 0; 1096 1097 debug3("send_pubkey_test"); 1098 1099 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1100 /* we cannot handle this key */ 1101 debug3("send_pubkey_test: cannot handle key"); 1102 return 0; 1103 } 1104 /* register callback for USERAUTH_PK_OK message */ 1105 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1106 1107 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1108 packet_put_cstring(authctxt->server_user); 1109 packet_put_cstring(authctxt->service); 1110 packet_put_cstring(authctxt->method->name); 1111 packet_put_char(have_sig); 1112 if (!(datafellows & SSH_BUG_PKAUTH)) 1113 packet_put_cstring(key_ssh_name(id->key)); 1114 packet_put_string(blob, bloblen); 1115 free(blob); 1116 packet_send(); 1117 return 1; 1118} 1119 1120static Key * 1121load_identity_file(char *filename, int userprovided) 1122{ 1123 Key *private; 1124 char prompt[300], *passphrase; 1125 int r, perm_ok = 0, quit = 0, i; 1126 struct stat st; 1127 1128 if (stat(filename, &st) < 0) { 1129 (userprovided ? logit : debug3)("no such identity: %s: %s", 1130 filename, strerror(errno)); 1131 return NULL; 1132 } 1133 snprintf(prompt, sizeof prompt, 1134 "Enter passphrase for key '%.100s': ", filename); 1135 for (i = 0; i <= options.number_of_password_prompts; i++) { 1136 if (i == 0) 1137 passphrase = ""; 1138 else { 1139 passphrase = read_passphrase(prompt, 0); 1140 if (*passphrase == '\0') { 1141 debug2("no passphrase given, try next key"); 1142 free(passphrase); 1143 break; 1144 } 1145 } 1146 switch ((r = sshkey_load_private_type(KEY_UNSPEC, filename, 1147 passphrase, &private, NULL, &perm_ok))) { 1148 case 0: 1149 break; 1150 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1151 if (options.batch_mode) { 1152 quit = 1; 1153 break; 1154 } 1155 if (i != 0) 1156 debug2("bad passphrase given, try again..."); 1157 break; 1158 case SSH_ERR_SYSTEM_ERROR: 1159 if (errno == ENOENT) { 1160 debug2("Load key \"%s\": %s", 1161 filename, ssh_err(r)); 1162 quit = 1; 1163 break; 1164 } 1165 /* FALLTHROUGH */ 1166 default: 1167 error("Load key \"%s\": %s", filename, ssh_err(r)); 1168 quit = 1; 1169 break; 1170 } 1171 if (i > 0) { 1172 explicit_bzero(passphrase, strlen(passphrase)); 1173 free(passphrase); 1174 } 1175 if (private != NULL || quit) 1176 break; 1177 } 1178 return private; 1179} 1180 1181/* 1182 * try keys in the following order: 1183 * 1. agent keys that are found in the config file 1184 * 2. other agent keys 1185 * 3. keys that are only listed in the config file 1186 */ 1187static void 1188pubkey_prepare(Authctxt *authctxt) 1189{ 1190 struct identity *id, *id2, *tmp; 1191 struct idlist agent, files, *preferred; 1192 struct sshkey *key; 1193 int agent_fd, i, r, found; 1194 size_t j; 1195 struct ssh_identitylist *idlist; 1196 1197 TAILQ_INIT(&agent); /* keys from the agent */ 1198 TAILQ_INIT(&files); /* keys from the config file */ 1199 preferred = &authctxt->keys; 1200 TAILQ_INIT(preferred); /* preferred order of keys */ 1201 1202 /* list of keys stored in the filesystem and PKCS#11 */ 1203 for (i = 0; i < options.num_identity_files; i++) { 1204 key = options.identity_keys[i]; 1205 if (key && key->type == KEY_RSA1) 1206 continue; 1207 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1208 continue; 1209 options.identity_keys[i] = NULL; 1210 id = xcalloc(1, sizeof(*id)); 1211 id->key = key; 1212 id->filename = xstrdup(options.identity_files[i]); 1213 id->userprovided = options.identity_file_userprovided[i]; 1214 TAILQ_INSERT_TAIL(&files, id, next); 1215 } 1216 /* Prefer PKCS11 keys that are explicitly listed */ 1217 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1218 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1219 continue; 1220 found = 0; 1221 TAILQ_FOREACH(id2, &files, next) { 1222 if (id2->key == NULL || 1223 (id2->key->flags & SSHKEY_FLAG_EXT) == 0) 1224 continue; 1225 if (sshkey_equal(id->key, id2->key)) { 1226 TAILQ_REMOVE(&files, id, next); 1227 TAILQ_INSERT_TAIL(preferred, id, next); 1228 found = 1; 1229 break; 1230 } 1231 } 1232 /* If IdentitiesOnly set and key not found then don't use it */ 1233 if (!found && options.identities_only) { 1234 TAILQ_REMOVE(&files, id, next); 1235 explicit_bzero(id, sizeof(*id)); 1236 free(id); 1237 } 1238 } 1239 /* list of keys supported by the agent */ 1240 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1241 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1242 debug("%s: ssh_get_authentication_socket: %s", 1243 __func__, ssh_err(r)); 1244 } else if ((r = ssh_fetch_identitylist(agent_fd, 2, &idlist)) != 0) { 1245 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1246 debug("%s: ssh_fetch_identitylist: %s", 1247 __func__, ssh_err(r)); 1248 } else { 1249 for (j = 0; j < idlist->nkeys; j++) { 1250 found = 0; 1251 TAILQ_FOREACH(id, &files, next) { 1252 /* 1253 * agent keys from the config file are 1254 * preferred 1255 */ 1256 if (sshkey_equal(idlist->keys[j], id->key)) { 1257 TAILQ_REMOVE(&files, id, next); 1258 TAILQ_INSERT_TAIL(preferred, id, next); 1259 id->agent_fd = agent_fd; 1260 found = 1; 1261 break; 1262 } 1263 } 1264 if (!found && !options.identities_only) { 1265 id = xcalloc(1, sizeof(*id)); 1266 /* XXX "steals" key/comment from idlist */ 1267 id->key = idlist->keys[j]; 1268 id->filename = idlist->comments[j]; 1269 idlist->keys[j] = NULL; 1270 idlist->comments[j] = NULL; 1271 id->agent_fd = agent_fd; 1272 TAILQ_INSERT_TAIL(&agent, id, next); 1273 } 1274 } 1275 ssh_free_identitylist(idlist); 1276 /* append remaining agent keys */ 1277 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1278 TAILQ_REMOVE(&agent, id, next); 1279 TAILQ_INSERT_TAIL(preferred, id, next); 1280 } 1281 authctxt->agent_fd = agent_fd; 1282 } 1283 /* append remaining keys from the config file */ 1284 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1285 TAILQ_REMOVE(&files, id, next); 1286 TAILQ_INSERT_TAIL(preferred, id, next); 1287 } 1288 TAILQ_FOREACH(id, preferred, next) { 1289 debug2("key: %s (%p),%s", id->filename, id->key, 1290 id->userprovided ? " explicit" : ""); 1291 } 1292} 1293 1294static void 1295pubkey_cleanup(Authctxt *authctxt) 1296{ 1297 Identity *id; 1298 1299 if (authctxt->agent_fd != -1) 1300 ssh_close_authentication_socket(authctxt->agent_fd); 1301 for (id = TAILQ_FIRST(&authctxt->keys); id; 1302 id = TAILQ_FIRST(&authctxt->keys)) { 1303 TAILQ_REMOVE(&authctxt->keys, id, next); 1304 if (id->key) 1305 sshkey_free(id->key); 1306 free(id->filename); 1307 free(id); 1308 } 1309} 1310 1311static int 1312try_identity(Identity *id) 1313{ 1314 if (!id->key) 1315 return (0); 1316 if (match_pattern_list(sshkey_ssh_name(id->key), 1317 options.pubkey_key_types, 0) != 1) { 1318 debug("Skipping %s key %s for not in PubkeyAcceptedKeyTypes", 1319 sshkey_ssh_name(id->key), id->filename); 1320 return (0); 1321 } 1322 if (key_type_plain(id->key->type) == KEY_RSA && 1323 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1324 debug("Skipped %s key %s for RSA/MD5 server", 1325 key_type(id->key), id->filename); 1326 return (0); 1327 } 1328 return (id->key->type != KEY_RSA1); 1329} 1330 1331int 1332userauth_pubkey(Authctxt *authctxt) 1333{ 1334 Identity *id; 1335 int sent = 0; 1336 1337 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1338 if (id->tried++) 1339 return (0); 1340 /* move key to the end of the queue */ 1341 TAILQ_REMOVE(&authctxt->keys, id, next); 1342 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1343 /* 1344 * send a test message if we have the public key. for 1345 * encrypted keys we cannot do this and have to load the 1346 * private key instead 1347 */ 1348 if (id->key != NULL) { 1349 if (try_identity(id)) { 1350 debug("Offering %s public key: %s", 1351 key_type(id->key), id->filename); 1352 sent = send_pubkey_test(authctxt, id); 1353 } 1354 } else { 1355 debug("Trying private key: %s", id->filename); 1356 id->key = load_identity_file(id->filename, 1357 id->userprovided); 1358 if (id->key != NULL) { 1359 if (try_identity(id)) { 1360 id->isprivate = 1; 1361 sent = sign_and_send_pubkey( 1362 authctxt, id); 1363 } 1364 key_free(id->key); 1365 id->key = NULL; 1366 } 1367 } 1368 if (sent) 1369 return (sent); 1370 } 1371 return (0); 1372} 1373 1374/* 1375 * Send userauth request message specifying keyboard-interactive method. 1376 */ 1377int 1378userauth_kbdint(Authctxt *authctxt) 1379{ 1380 static int attempt = 0; 1381 1382 if (attempt++ >= options.number_of_password_prompts) 1383 return 0; 1384 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1385 if (attempt > 1 && !authctxt->info_req_seen) { 1386 debug3("userauth_kbdint: disable: no info_req_seen"); 1387 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1388 return 0; 1389 } 1390 1391 debug2("userauth_kbdint"); 1392 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1393 packet_put_cstring(authctxt->server_user); 1394 packet_put_cstring(authctxt->service); 1395 packet_put_cstring(authctxt->method->name); 1396 packet_put_cstring(""); /* lang */ 1397 packet_put_cstring(options.kbd_interactive_devices ? 1398 options.kbd_interactive_devices : ""); 1399 packet_send(); 1400 1401 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1402 return 1; 1403} 1404 1405/* 1406 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1407 */ 1408int 1409input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1410{ 1411 Authctxt *authctxt = ctxt; 1412 char *name, *inst, *lang, *prompt, *response; 1413 u_int num_prompts, i; 1414 int echo = 0; 1415 1416 debug2("input_userauth_info_req"); 1417 1418 if (authctxt == NULL) 1419 fatal("input_userauth_info_req: no authentication context"); 1420 1421 authctxt->info_req_seen = 1; 1422 1423 name = packet_get_string(NULL); 1424 inst = packet_get_string(NULL); 1425 lang = packet_get_string(NULL); 1426 if (strlen(name) > 0) 1427 logit("%s", name); 1428 if (strlen(inst) > 0) 1429 logit("%s", inst); 1430 free(name); 1431 free(inst); 1432 free(lang); 1433 1434 num_prompts = packet_get_int(); 1435 /* 1436 * Begin to build info response packet based on prompts requested. 1437 * We commit to providing the correct number of responses, so if 1438 * further on we run into a problem that prevents this, we have to 1439 * be sure and clean this up and send a correct error response. 1440 */ 1441 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1442 packet_put_int(num_prompts); 1443 1444 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1445 for (i = 0; i < num_prompts; i++) { 1446 prompt = packet_get_string(NULL); 1447 echo = packet_get_char(); 1448 1449 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1450 1451 packet_put_cstring(response); 1452 explicit_bzero(response, strlen(response)); 1453 free(response); 1454 free(prompt); 1455 } 1456 packet_check_eom(); /* done with parsing incoming message. */ 1457 1458 packet_add_padding(64); 1459 packet_send(); 1460 return 0; 1461} 1462 1463static int 1464ssh_keysign(struct sshkey *key, u_char **sigp, size_t *lenp, 1465 const u_char *data, size_t datalen) 1466{ 1467 struct sshbuf *b; 1468 struct stat st; 1469 pid_t pid; 1470 int i, r, to[2], from[2], status, sock = packet_get_connection_in(); 1471 u_char rversion = 0, version = 2; 1472 void (*osigchld)(int); 1473 1474 *sigp = NULL; 1475 *lenp = 0; 1476 1477 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1478 error("%s: not installed: %s", __func__, strerror(errno)); 1479 return -1; 1480 } 1481 if (fflush(stdout) != 0) { 1482 error("%s: fflush: %s", __func__, strerror(errno)); 1483 return -1; 1484 } 1485 if (pipe(to) < 0) { 1486 error("%s: pipe: %s", __func__, strerror(errno)); 1487 return -1; 1488 } 1489 if (pipe(from) < 0) { 1490 error("%s: pipe: %s", __func__, strerror(errno)); 1491 return -1; 1492 } 1493 if ((pid = fork()) < 0) { 1494 error("%s: fork: %s", __func__, strerror(errno)); 1495 return -1; 1496 } 1497 osigchld = signal(SIGCHLD, SIG_DFL); 1498 if (pid == 0) { 1499 /* keep the socket on exec */ 1500 fcntl(sock, F_SETFD, 0); 1501 permanently_drop_suid(getuid()); 1502 close(from[0]); 1503 if (dup2(from[1], STDOUT_FILENO) < 0) 1504 fatal("%s: dup2: %s", __func__, strerror(errno)); 1505 close(to[1]); 1506 if (dup2(to[0], STDIN_FILENO) < 0) 1507 fatal("%s: dup2: %s", __func__, strerror(errno)); 1508 close(from[1]); 1509 close(to[0]); 1510 /* Close everything but stdio and the socket */ 1511 for (i = STDERR_FILENO + 1; i < sock; i++) 1512 close(i); 1513 closefrom(sock + 1); 1514 debug3("%s: [child] pid=%ld, exec %s", 1515 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1516 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1517 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1518 strerror(errno)); 1519 } 1520 close(from[1]); 1521 close(to[0]); 1522 1523 if ((b = sshbuf_new()) == NULL) 1524 fatal("%s: sshbuf_new failed", __func__); 1525 /* send # of sock, data to be signed */ 1526 if ((r = sshbuf_put_u32(b, sock) != 0) || 1527 (r = sshbuf_put_string(b, data, datalen)) != 0) 1528 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1529 if (ssh_msg_send(to[1], version, b) == -1) 1530 fatal("%s: couldn't send request", __func__); 1531 sshbuf_reset(b); 1532 r = ssh_msg_recv(from[0], b); 1533 close(from[0]); 1534 close(to[1]); 1535 if (r < 0) { 1536 error("%s: no reply", __func__); 1537 goto fail; 1538 } 1539 1540 errno = 0; 1541 while (waitpid(pid, &status, 0) < 0) { 1542 if (errno != EINTR) { 1543 error("%s: waitpid %ld: %s", 1544 __func__, (long)pid, strerror(errno)); 1545 goto fail; 1546 } 1547 } 1548 if (!WIFEXITED(status)) { 1549 error("%s: exited abnormally", __func__); 1550 goto fail; 1551 } 1552 if (WEXITSTATUS(status) != 0) { 1553 error("%s: exited with status %d", 1554 __func__, WEXITSTATUS(status)); 1555 goto fail; 1556 } 1557 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 1558 error("%s: buffer error: %s", __func__, ssh_err(r)); 1559 goto fail; 1560 } 1561 if (rversion != version) { 1562 error("%s: bad version", __func__); 1563 goto fail; 1564 } 1565 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 1566 error("%s: buffer error: %s", __func__, ssh_err(r)); 1567 fail: 1568 signal(SIGCHLD, osigchld); 1569 sshbuf_free(b); 1570 return -1; 1571 } 1572 signal(SIGCHLD, osigchld); 1573 sshbuf_free(b); 1574 1575 return 0; 1576} 1577 1578int 1579userauth_hostbased(Authctxt *authctxt) 1580{ 1581 struct ssh *ssh = active_state; 1582 struct sshkey *private = NULL; 1583 struct sshbuf *b = NULL; 1584 const char *service; 1585 u_char *sig = NULL, *keyblob = NULL; 1586 char *fp = NULL, *chost = NULL, *lname = NULL; 1587 size_t siglen = 0, keylen = 0; 1588 int i, r, success = 0; 1589 1590 if (authctxt->ktypes == NULL) { 1591 authctxt->oktypes = xstrdup(options.hostbased_key_types); 1592 authctxt->ktypes = authctxt->oktypes; 1593 } 1594 1595 /* 1596 * Work through each listed type pattern in HostbasedKeyTypes, 1597 * trying each hostkey that matches the type in turn. 1598 */ 1599 for (;;) { 1600 if (authctxt->active_ktype == NULL) 1601 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 1602 if (authctxt->active_ktype == NULL || 1603 *authctxt->active_ktype == '\0') 1604 break; 1605 debug3("%s: trying key type %s", __func__, 1606 authctxt->active_ktype); 1607 1608 /* check for a useful key */ 1609 private = NULL; 1610 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 1611 if (authctxt->sensitive->keys[i] == NULL || 1612 authctxt->sensitive->keys[i]->type == KEY_RSA1 || 1613 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 1614 continue; 1615 if (match_pattern_list( 1616 sshkey_ssh_name(authctxt->sensitive->keys[i]), 1617 authctxt->active_ktype, 0) != 1) 1618 continue; 1619 /* we take and free the key */ 1620 private = authctxt->sensitive->keys[i]; 1621 authctxt->sensitive->keys[i] = NULL; 1622 break; 1623 } 1624 /* Found one */ 1625 if (private != NULL) 1626 break; 1627 /* No more keys of this type; advance */ 1628 authctxt->active_ktype = NULL; 1629 } 1630 if (private == NULL) { 1631 free(authctxt->oktypes); 1632 authctxt->oktypes = authctxt->ktypes = NULL; 1633 authctxt->active_ktype = NULL; 1634 debug("No more client hostkeys for hostbased authentication."); 1635 goto out; 1636 } 1637 1638 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 1639 SSH_FP_DEFAULT)) == NULL) { 1640 error("%s: sshkey_fingerprint failed", __func__); 1641 goto out; 1642 } 1643 debug("%s: trying hostkey %s %s", 1644 __func__, sshkey_ssh_name(private), fp); 1645 1646 /* figure out a name for the client host */ 1647 if ((lname = get_local_name(packet_get_connection_in())) == NULL) { 1648 error("%s: cannot get local ipaddr/name", __func__); 1649 goto out; 1650 } 1651 1652 /* XXX sshbuf_put_stringf? */ 1653 xasprintf(&chost, "%s.", lname); 1654 debug2("%s: chost %s", __func__, chost); 1655 1656 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1657 authctxt->service; 1658 1659 /* construct data */ 1660 if ((b = sshbuf_new()) == NULL) { 1661 error("%s: sshbuf_new failed", __func__); 1662 goto out; 1663 } 1664 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 1665 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 1666 goto out; 1667 } 1668 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 1669 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1670 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1671 (r = sshbuf_put_cstring(b, service)) != 0 || 1672 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1673 (r = sshbuf_put_cstring(b, key_ssh_name(private))) != 0 || 1674 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 1675 (r = sshbuf_put_cstring(b, chost)) != 0 || 1676 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 1677 error("%s: buffer error: %s", __func__, ssh_err(r)); 1678 goto out; 1679 } 1680 1681#ifdef DEBUG_PK 1682 sshbuf_dump(b, stderr); 1683#endif 1684 if (authctxt->sensitive->external_keysign) 1685 r = ssh_keysign(private, &sig, &siglen, 1686 sshbuf_ptr(b), sshbuf_len(b)); 1687 else if ((r = sshkey_sign(private, &sig, &siglen, 1688 sshbuf_ptr(b), sshbuf_len(b), datafellows)) != 0) 1689 debug("%s: sshkey_sign: %s", __func__, ssh_err(r)); 1690 if (r != 0) { 1691 error("sign using hostkey %s %s failed", 1692 sshkey_ssh_name(private), fp); 1693 goto out; 1694 } 1695 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1696 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1697 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1698 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1699 (r = sshpkt_put_cstring(ssh, key_ssh_name(private))) != 0 || 1700 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 1701 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 1702 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 1703 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 1704 (r = sshpkt_send(ssh)) != 0) { 1705 error("%s: packet error: %s", __func__, ssh_err(r)); 1706 goto out; 1707 } 1708 success = 1; 1709 1710 out: 1711 if (sig != NULL) { 1712 explicit_bzero(sig, siglen); 1713 free(sig); 1714 } 1715 free(keyblob); 1716 free(lname); 1717 free(fp); 1718 free(chost); 1719 sshkey_free(private); 1720 sshbuf_free(b); 1721 1722 return success; 1723} 1724 1725/* find auth method */ 1726 1727/* 1728 * given auth method name, if configurable options permit this method fill 1729 * in auth_ident field and return true, otherwise return false. 1730 */ 1731static int 1732authmethod_is_enabled(Authmethod *method) 1733{ 1734 if (method == NULL) 1735 return 0; 1736 /* return false if options indicate this method is disabled */ 1737 if (method->enabled == NULL || *method->enabled == 0) 1738 return 0; 1739 /* return false if batch mode is enabled but method needs interactive mode */ 1740 if (method->batch_flag != NULL && *method->batch_flag != 0) 1741 return 0; 1742 return 1; 1743} 1744 1745static Authmethod * 1746authmethod_lookup(const char *name) 1747{ 1748 Authmethod *method = NULL; 1749 if (name != NULL) 1750 for (method = authmethods; method->name != NULL; method++) 1751 if (strcmp(name, method->name) == 0) 1752 return method; 1753 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1754 return NULL; 1755} 1756 1757/* XXX internal state */ 1758static Authmethod *current = NULL; 1759static char *supported = NULL; 1760static char *preferred = NULL; 1761 1762/* 1763 * Given the authentication method list sent by the server, return the 1764 * next method we should try. If the server initially sends a nil list, 1765 * use a built-in default list. 1766 */ 1767static Authmethod * 1768authmethod_get(char *authlist) 1769{ 1770 char *name = NULL; 1771 u_int next; 1772 1773 /* Use a suitable default if we're passed a nil list. */ 1774 if (authlist == NULL || strlen(authlist) == 0) 1775 authlist = options.preferred_authentications; 1776 1777 if (supported == NULL || strcmp(authlist, supported) != 0) { 1778 debug3("start over, passed a different list %s", authlist); 1779 free(supported); 1780 supported = xstrdup(authlist); 1781 preferred = options.preferred_authentications; 1782 debug3("preferred %s", preferred); 1783 current = NULL; 1784 } else if (current != NULL && authmethod_is_enabled(current)) 1785 return current; 1786 1787 for (;;) { 1788 if ((name = match_list(preferred, supported, &next)) == NULL) { 1789 debug("No more authentication methods to try."); 1790 current = NULL; 1791 return NULL; 1792 } 1793 preferred += next; 1794 debug3("authmethod_lookup %s", name); 1795 debug3("remaining preferred: %s", preferred); 1796 if ((current = authmethod_lookup(name)) != NULL && 1797 authmethod_is_enabled(current)) { 1798 debug3("authmethod_is_enabled %s", name); 1799 debug("Next authentication method: %s", name); 1800 free(name); 1801 return current; 1802 } 1803 free(name); 1804 } 1805} 1806 1807static char * 1808authmethods_get(void) 1809{ 1810 Authmethod *method = NULL; 1811 Buffer b; 1812 char *list; 1813 1814 buffer_init(&b); 1815 for (method = authmethods; method->name != NULL; method++) { 1816 if (authmethod_is_enabled(method)) { 1817 if (buffer_len(&b) > 0) 1818 buffer_append(&b, ",", 1); 1819 buffer_append(&b, method->name, strlen(method->name)); 1820 } 1821 } 1822 buffer_append(&b, "\0", 1); 1823 list = xstrdup(buffer_ptr(&b)); 1824 buffer_free(&b); 1825 return list; 1826} 1827 1828