1 /* $OpenBSD: sshconnect2.c,v 1.189 2012/06/22 12:30:26 dtucker Exp $ */ 2 /* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/types.h> 28 #include <sys/socket.h> 29 #include <sys/wait.h> 30 #include <sys/queue.h> 31 #include <sys/stat.h> 32 33 #include <errno.h> 34 #include <fcntl.h> 35 #include <netdb.h> 36 #include <stdio.h> 37 #include <string.h> 38 #include <signal.h> 39 #include <pwd.h> 40 #include <unistd.h> 41 #include <vis.h> 42 43 #include "xmalloc.h" 44 #include "ssh.h" 45 #include "ssh2.h" 46 #include "buffer.h" 47 #include "packet.h" 48 #include "compat.h" 49 #include "cipher.h" 50 #include "key.h" 51 #include "kex.h" 52 #include "myproposal.h" 53 #include "sshconnect.h" 54 #include "authfile.h" 55 #include "dh.h" 56 #include "authfd.h" 57 #include "log.h" 58 #include "readconf.h" 59 #include "misc.h" 60 #include "match.h" 61 #include "dispatch.h" 62 #include "canohost.h" 63 #include "msg.h" 64 #include "pathnames.h" 65 #include "uidswap.h" 66 #include "hostfile.h" 67 #include "schnorr.h" 68 #include "jpake.h" 69 70 #ifdef GSSAPI 71 #include "ssh-gss.h" 72 #endif 73 74 /* import */ 75 extern char *client_version_string; 76 extern char *server_version_string; 77 extern Options options; 78 79 /* 80 * SSH2 key exchange 81 */ 82 83 u_char *session_id2 = NULL; 84 u_int session_id2_len = 0; 85 86 char *xxx_host; 87 struct sockaddr *xxx_hostaddr; 88 89 Kex *xxx_kex = NULL; 90 91 static int 92 verify_host_key_callback(Key *hostkey) 93 { 94 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 95 fatal("Host key verification failed."); 96 return 0; 97 } 98 99 static char * 100 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 101 { 102 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 103 size_t maxlen; 104 struct hostkeys *hostkeys; 105 int ktype; 106 u_int i; 107 108 /* Find all hostkeys for this hostname */ 109 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 110 hostkeys = init_hostkeys(); 111 for (i = 0; i < options.num_user_hostfiles; i++) 112 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 113 for (i = 0; i < options.num_system_hostfiles; i++) 114 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 115 116 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 117 maxlen = strlen(avail) + 1; 118 first = xmalloc(maxlen); 119 last = xmalloc(maxlen); 120 *first = *last = '\0'; 121 122 #define ALG_APPEND(to, from) \ 123 do { \ 124 if (*to != '\0') \ 125 strlcat(to, ",", maxlen); \ 126 strlcat(to, from, maxlen); \ 127 } while (0) 128 129 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 130 if ((ktype = key_type_from_name(alg)) == KEY_UNSPEC) 131 fatal("%s: unknown alg %s", __func__, alg); 132 if (lookup_key_in_hostkeys_by_type(hostkeys, 133 key_type_plain(ktype), NULL)) 134 ALG_APPEND(first, alg); 135 else 136 ALG_APPEND(last, alg); 137 } 138 #undef ALG_APPEND 139 xasprintf(&ret, "%s%s%s", first, *first == '\0' ? "" : ",", last); 140 if (*first != '\0') 141 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 142 143 xfree(first); 144 xfree(last); 145 xfree(hostname); 146 xfree(oavail); 147 free_hostkeys(hostkeys); 148 149 return ret; 150 } 151 152 void 153 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 154 { 155 Kex *kex; 156 157 xxx_host = host; 158 xxx_hostaddr = hostaddr; 159 160 if (options.ciphers == (char *)-1) { 161 logit("No valid ciphers for protocol version 2 given, using defaults."); 162 options.ciphers = NULL; 163 } 164 if (options.ciphers != NULL) { 165 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 166 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 167 } 168 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 169 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 170 myproposal[PROPOSAL_ENC_ALGS_STOC] = 171 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 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 if (options.macs != NULL) { 180 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 181 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 182 } 183 if (options.hostkeyalgorithms != NULL) 184 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 185 options.hostkeyalgorithms; 186 else { 187 /* Prefer algorithms that we already have keys for */ 188 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 189 order_hostkeyalgs(host, hostaddr, port); 190 } 191 if (options.kex_algorithms != NULL) 192 myproposal[PROPOSAL_KEX_ALGS] = options.kex_algorithms; 193 194 if (options.rekey_limit) 195 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 196 197 /* start key exchange */ 198 kex = kex_setup(myproposal); 199 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 200 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 201 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 202 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 203 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 204 kex->client_version_string=client_version_string; 205 kex->server_version_string=server_version_string; 206 kex->verify_host_key=&verify_host_key_callback; 207 208 xxx_kex = kex; 209 210 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 211 212 if (options.use_roaming && !kex->roaming) { 213 debug("Roaming not allowed by server"); 214 options.use_roaming = 0; 215 } 216 217 session_id2 = kex->session_id; 218 session_id2_len = kex->session_id_len; 219 220 #ifdef DEBUG_KEXDH 221 /* send 1st encrypted/maced/compressed message */ 222 packet_start(SSH2_MSG_IGNORE); 223 packet_put_cstring("markus"); 224 packet_send(); 225 packet_write_wait(); 226 #endif 227 } 228 229 /* 230 * Authenticate user 231 */ 232 233 typedef struct Authctxt Authctxt; 234 typedef struct Authmethod Authmethod; 235 typedef struct identity Identity; 236 typedef struct idlist Idlist; 237 238 struct identity { 239 TAILQ_ENTRY(identity) next; 240 AuthenticationConnection *ac; /* set if agent supports key */ 241 Key *key; /* public/private key */ 242 char *filename; /* comment for agent-only keys */ 243 int tried; 244 int isprivate; /* key points to the private key */ 245 }; 246 TAILQ_HEAD(idlist, identity); 247 248 struct Authctxt { 249 const char *server_user; 250 const char *local_user; 251 const char *host; 252 const char *service; 253 Authmethod *method; 254 sig_atomic_t success; 255 char *authlist; 256 /* pubkey */ 257 Idlist keys; 258 AuthenticationConnection *agent; 259 /* hostbased */ 260 Sensitive *sensitive; 261 /* kbd-interactive */ 262 int info_req_seen; 263 /* generic */ 264 void *methoddata; 265 }; 266 struct Authmethod { 267 char *name; /* string to compare against server's list */ 268 int (*userauth)(Authctxt *authctxt); 269 void (*cleanup)(Authctxt *authctxt); 270 int *enabled; /* flag in option struct that enables method */ 271 int *batch_flag; /* flag in option struct that disables method */ 272 }; 273 274 void input_userauth_success(int, u_int32_t, void *); 275 void input_userauth_success_unexpected(int, u_int32_t, void *); 276 void input_userauth_failure(int, u_int32_t, void *); 277 void input_userauth_banner(int, u_int32_t, void *); 278 void input_userauth_error(int, u_int32_t, void *); 279 void input_userauth_info_req(int, u_int32_t, void *); 280 void input_userauth_pk_ok(int, u_int32_t, void *); 281 void input_userauth_passwd_changereq(int, u_int32_t, void *); 282 void input_userauth_jpake_server_step1(int, u_int32_t, void *); 283 void input_userauth_jpake_server_step2(int, u_int32_t, void *); 284 void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 285 286 int userauth_none(Authctxt *); 287 int userauth_pubkey(Authctxt *); 288 int userauth_passwd(Authctxt *); 289 int userauth_kbdint(Authctxt *); 290 int userauth_hostbased(Authctxt *); 291 int userauth_jpake(Authctxt *); 292 293 void userauth_jpake_cleanup(Authctxt *); 294 295 #ifdef GSSAPI 296 int userauth_gssapi(Authctxt *authctxt); 297 void input_gssapi_response(int type, u_int32_t, void *); 298 void input_gssapi_token(int type, u_int32_t, void *); 299 void input_gssapi_hash(int type, u_int32_t, void *); 300 void input_gssapi_error(int, u_int32_t, void *); 301 void input_gssapi_errtok(int, u_int32_t, void *); 302 #endif 303 304 void userauth(Authctxt *, char *); 305 306 static int sign_and_send_pubkey(Authctxt *, Identity *); 307 static void pubkey_prepare(Authctxt *); 308 static void pubkey_cleanup(Authctxt *); 309 static Key *load_identity_file(char *); 310 311 static Authmethod *authmethod_get(char *authlist); 312 static Authmethod *authmethod_lookup(const char *name); 313 static char *authmethods_get(void); 314 315 Authmethod authmethods[] = { 316 #ifdef GSSAPI 317 {"gssapi-with-mic", 318 userauth_gssapi, 319 NULL, 320 &options.gss_authentication, 321 NULL}, 322 #endif 323 {"hostbased", 324 userauth_hostbased, 325 NULL, 326 &options.hostbased_authentication, 327 NULL}, 328 {"publickey", 329 userauth_pubkey, 330 NULL, 331 &options.pubkey_authentication, 332 NULL}, 333 #ifdef JPAKE 334 {"jpake-01@openssh.com", 335 userauth_jpake, 336 userauth_jpake_cleanup, 337 &options.zero_knowledge_password_authentication, 338 &options.batch_mode}, 339 #endif 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 }; 357 358 void 359 ssh_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 xfree(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.info_req_seen = 0; 402 if (authctxt.method == NULL) 403 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 404 405 /* initial userauth request */ 406 userauth_none(&authctxt); 407 408 dispatch_init(&input_userauth_error); 409 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 410 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 411 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 412 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 413 414 pubkey_cleanup(&authctxt); 415 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 416 417 debug("Authentication succeeded (%s).", authctxt.method->name); 418 } 419 420 void 421 userauth(Authctxt *authctxt, char *authlist) 422 { 423 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 424 authctxt->method->cleanup(authctxt); 425 426 if (authctxt->methoddata) { 427 xfree(authctxt->methoddata); 428 authctxt->methoddata = NULL; 429 } 430 if (authlist == NULL) { 431 authlist = authctxt->authlist; 432 } else { 433 if (authctxt->authlist) 434 xfree(authctxt->authlist); 435 authctxt->authlist = authlist; 436 } 437 for (;;) { 438 Authmethod *method = authmethod_get(authlist); 439 if (method == NULL) 440 fatal("Permission denied (%s).", authlist); 441 authctxt->method = method; 442 443 /* reset the per method handler */ 444 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 445 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 446 447 /* and try new method */ 448 if (method->userauth(authctxt) != 0) { 449 debug2("we sent a %s packet, wait for reply", method->name); 450 break; 451 } else { 452 debug2("we did not send a packet, disable method"); 453 method->enabled = NULL; 454 } 455 } 456 } 457 458 /* ARGSUSED */ 459 void 460 input_userauth_error(int type, u_int32_t seq, void *ctxt) 461 { 462 fatal("input_userauth_error: bad message during authentication: " 463 "type %d", type); 464 } 465 466 /* ARGSUSED */ 467 void 468 input_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 xfree(msg); 483 } 484 xfree(raw); 485 xfree(lang); 486 } 487 488 /* ARGSUSED */ 489 void 490 input_userauth_success(int type, u_int32_t seq, void *ctxt) 491 { 492 Authctxt *authctxt = ctxt; 493 494 if (authctxt == NULL) 495 fatal("input_userauth_success: no authentication context"); 496 if (authctxt->authlist) { 497 xfree(authctxt->authlist); 498 authctxt->authlist = NULL; 499 } 500 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 501 authctxt->method->cleanup(authctxt); 502 if (authctxt->methoddata) { 503 xfree(authctxt->methoddata); 504 authctxt->methoddata = NULL; 505 } 506 authctxt->success = 1; /* break out */ 507 } 508 509 void 510 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 511 { 512 Authctxt *authctxt = ctxt; 513 514 if (authctxt == NULL) 515 fatal("%s: no authentication context", __func__); 516 517 fatal("Unexpected authentication success during %s.", 518 authctxt->method->name); 519 } 520 521 /* ARGSUSED */ 522 void 523 input_userauth_failure(int type, u_int32_t seq, void *ctxt) 524 { 525 Authctxt *authctxt = ctxt; 526 char *authlist = NULL; 527 int partial; 528 529 if (authctxt == NULL) 530 fatal("input_userauth_failure: no authentication context"); 531 532 authlist = packet_get_string(NULL); 533 partial = packet_get_char(); 534 packet_check_eom(); 535 536 if (partial != 0) 537 logit("Authenticated with partial success."); 538 debug("Authentications that can continue: %s", authlist); 539 540 userauth(authctxt, authlist); 541 } 542 543 /* ARGSUSED */ 544 void 545 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 546 { 547 Authctxt *authctxt = ctxt; 548 Key *key = NULL; 549 Identity *id = NULL; 550 Buffer b; 551 int pktype, sent = 0; 552 u_int alen, blen; 553 char *pkalg, *fp; 554 u_char *pkblob; 555 556 if (authctxt == NULL) 557 fatal("input_userauth_pk_ok: no authentication context"); 558 if (datafellows & SSH_BUG_PKOK) { 559 /* this is similar to SSH_BUG_PKAUTH */ 560 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 561 pkblob = packet_get_string(&blen); 562 buffer_init(&b); 563 buffer_append(&b, pkblob, blen); 564 pkalg = buffer_get_string(&b, &alen); 565 buffer_free(&b); 566 } else { 567 pkalg = packet_get_string(&alen); 568 pkblob = packet_get_string(&blen); 569 } 570 packet_check_eom(); 571 572 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 573 574 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 575 debug("unknown pkalg %s", pkalg); 576 goto done; 577 } 578 if ((key = key_from_blob(pkblob, blen)) == NULL) { 579 debug("no key from blob. pkalg %s", pkalg); 580 goto done; 581 } 582 if (key->type != pktype) { 583 error("input_userauth_pk_ok: type mismatch " 584 "for decoded key (received %d, expected %d)", 585 key->type, pktype); 586 goto done; 587 } 588 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 589 debug2("input_userauth_pk_ok: fp %s", fp); 590 xfree(fp); 591 592 /* 593 * search keys in the reverse order, because last candidate has been 594 * moved to the end of the queue. this also avoids confusion by 595 * duplicate keys 596 */ 597 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 598 if (key_equal(key, id->key)) { 599 sent = sign_and_send_pubkey(authctxt, id); 600 break; 601 } 602 } 603 done: 604 if (key != NULL) 605 key_free(key); 606 xfree(pkalg); 607 xfree(pkblob); 608 609 /* try another method if we did not send a packet */ 610 if (sent == 0) 611 userauth(authctxt, NULL); 612 } 613 614 #ifdef GSSAPI 615 int 616 userauth_gssapi(Authctxt *authctxt) 617 { 618 Gssctxt *gssctxt = NULL; 619 static gss_OID_set gss_supported = NULL; 620 static u_int mech = 0; 621 OM_uint32 min; 622 int ok = 0; 623 624 /* Try one GSSAPI method at a time, rather than sending them all at 625 * once. */ 626 627 if (gss_supported == NULL) 628 gss_indicate_mechs(&min, &gss_supported); 629 630 /* Check to see if the mechanism is usable before we offer it */ 631 while (mech < gss_supported->count && !ok) { 632 /* My DER encoding requires length<128 */ 633 if (gss_supported->elements[mech].length < 128 && 634 ssh_gssapi_check_mechanism(&gssctxt, 635 &gss_supported->elements[mech], authctxt->host)) { 636 ok = 1; /* Mechanism works */ 637 } else { 638 mech++; 639 } 640 } 641 642 if (!ok) 643 return 0; 644 645 authctxt->methoddata=(void *)gssctxt; 646 647 packet_start(SSH2_MSG_USERAUTH_REQUEST); 648 packet_put_cstring(authctxt->server_user); 649 packet_put_cstring(authctxt->service); 650 packet_put_cstring(authctxt->method->name); 651 652 packet_put_int(1); 653 654 packet_put_int((gss_supported->elements[mech].length) + 2); 655 packet_put_char(SSH_GSS_OIDTYPE); 656 packet_put_char(gss_supported->elements[mech].length); 657 packet_put_raw(gss_supported->elements[mech].elements, 658 gss_supported->elements[mech].length); 659 660 packet_send(); 661 662 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 663 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 664 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 665 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 666 667 mech++; /* Move along to next candidate */ 668 669 return 1; 670 } 671 672 static OM_uint32 673 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 674 { 675 Authctxt *authctxt = ctxt; 676 Gssctxt *gssctxt = authctxt->methoddata; 677 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 678 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 679 gss_buffer_desc gssbuf; 680 OM_uint32 status, ms, flags; 681 Buffer b; 682 683 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 684 recv_tok, &send_tok, &flags); 685 686 if (send_tok.length > 0) { 687 if (GSS_ERROR(status)) 688 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 689 else 690 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 691 692 packet_put_string(send_tok.value, send_tok.length); 693 packet_send(); 694 gss_release_buffer(&ms, &send_tok); 695 } 696 697 if (status == GSS_S_COMPLETE) { 698 /* send either complete or MIC, depending on mechanism */ 699 if (!(flags & GSS_C_INTEG_FLAG)) { 700 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 701 packet_send(); 702 } else { 703 ssh_gssapi_buildmic(&b, authctxt->server_user, 704 authctxt->service, "gssapi-with-mic"); 705 706 gssbuf.value = buffer_ptr(&b); 707 gssbuf.length = buffer_len(&b); 708 709 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 710 711 if (!GSS_ERROR(status)) { 712 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 713 packet_put_string(mic.value, mic.length); 714 715 packet_send(); 716 } 717 718 buffer_free(&b); 719 gss_release_buffer(&ms, &mic); 720 } 721 } 722 723 return status; 724 } 725 726 /* ARGSUSED */ 727 void 728 input_gssapi_response(int type, u_int32_t plen, void *ctxt) 729 { 730 Authctxt *authctxt = ctxt; 731 Gssctxt *gssctxt; 732 int oidlen; 733 char *oidv; 734 735 if (authctxt == NULL) 736 fatal("input_gssapi_response: no authentication context"); 737 gssctxt = authctxt->methoddata; 738 739 /* Setup our OID */ 740 oidv = packet_get_string(&oidlen); 741 742 if (oidlen <= 2 || 743 oidv[0] != SSH_GSS_OIDTYPE || 744 oidv[1] != oidlen - 2) { 745 xfree(oidv); 746 debug("Badly encoded mechanism OID received"); 747 userauth(authctxt, NULL); 748 return; 749 } 750 751 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 752 fatal("Server returned different OID than expected"); 753 754 packet_check_eom(); 755 756 xfree(oidv); 757 758 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 759 /* Start again with next method on list */ 760 debug("Trying to start again"); 761 userauth(authctxt, NULL); 762 return; 763 } 764 } 765 766 /* ARGSUSED */ 767 void 768 input_gssapi_token(int type, u_int32_t plen, void *ctxt) 769 { 770 Authctxt *authctxt = ctxt; 771 gss_buffer_desc recv_tok; 772 OM_uint32 status; 773 u_int slen; 774 775 if (authctxt == NULL) 776 fatal("input_gssapi_response: no authentication context"); 777 778 recv_tok.value = packet_get_string(&slen); 779 recv_tok.length = slen; /* safe typecast */ 780 781 packet_check_eom(); 782 783 status = process_gssapi_token(ctxt, &recv_tok); 784 785 xfree(recv_tok.value); 786 787 if (GSS_ERROR(status)) { 788 /* Start again with the next method in the list */ 789 userauth(authctxt, NULL); 790 return; 791 } 792 } 793 794 /* ARGSUSED */ 795 void 796 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 797 { 798 Authctxt *authctxt = ctxt; 799 Gssctxt *gssctxt; 800 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 801 gss_buffer_desc recv_tok; 802 OM_uint32 status, ms; 803 u_int len; 804 805 if (authctxt == NULL) 806 fatal("input_gssapi_response: no authentication context"); 807 gssctxt = authctxt->methoddata; 808 809 recv_tok.value = packet_get_string(&len); 810 recv_tok.length = len; 811 812 packet_check_eom(); 813 814 /* Stick it into GSSAPI and see what it says */ 815 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 816 &recv_tok, &send_tok, NULL); 817 818 xfree(recv_tok.value); 819 gss_release_buffer(&ms, &send_tok); 820 821 /* Server will be returning a failed packet after this one */ 822 } 823 824 /* ARGSUSED */ 825 void 826 input_gssapi_error(int type, u_int32_t plen, void *ctxt) 827 { 828 OM_uint32 maj, min; 829 char *msg; 830 char *lang; 831 832 maj=packet_get_int(); 833 min=packet_get_int(); 834 msg=packet_get_string(NULL); 835 lang=packet_get_string(NULL); 836 837 packet_check_eom(); 838 839 debug("Server GSSAPI Error:\n%s", msg); 840 xfree(msg); 841 xfree(lang); 842 } 843 #endif /* GSSAPI */ 844 845 int 846 userauth_none(Authctxt *authctxt) 847 { 848 /* initial userauth request */ 849 packet_start(SSH2_MSG_USERAUTH_REQUEST); 850 packet_put_cstring(authctxt->server_user); 851 packet_put_cstring(authctxt->service); 852 packet_put_cstring(authctxt->method->name); 853 packet_send(); 854 return 1; 855 } 856 857 int 858 userauth_passwd(Authctxt *authctxt) 859 { 860 static int attempt = 0; 861 char prompt[150]; 862 char *password; 863 const char *host = options.host_key_alias ? options.host_key_alias : 864 authctxt->host; 865 866 if (attempt++ >= options.number_of_password_prompts) 867 return 0; 868 869 if (attempt != 1) 870 error("Permission denied, please try again."); 871 872 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 873 authctxt->server_user, host); 874 password = read_passphrase(prompt, 0); 875 packet_start(SSH2_MSG_USERAUTH_REQUEST); 876 packet_put_cstring(authctxt->server_user); 877 packet_put_cstring(authctxt->service); 878 packet_put_cstring(authctxt->method->name); 879 packet_put_char(0); 880 packet_put_cstring(password); 881 memset(password, 0, strlen(password)); 882 xfree(password); 883 packet_add_padding(64); 884 packet_send(); 885 886 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 887 &input_userauth_passwd_changereq); 888 889 return 1; 890 } 891 892 /* 893 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 894 */ 895 /* ARGSUSED */ 896 void 897 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 898 { 899 Authctxt *authctxt = ctxt; 900 char *info, *lang, *password = NULL, *retype = NULL; 901 char prompt[150]; 902 const char *host = options.host_key_alias ? options.host_key_alias : 903 authctxt->host; 904 905 debug2("input_userauth_passwd_changereq"); 906 907 if (authctxt == NULL) 908 fatal("input_userauth_passwd_changereq: " 909 "no authentication context"); 910 911 info = packet_get_string(NULL); 912 lang = packet_get_string(NULL); 913 if (strlen(info) > 0) 914 logit("%s", info); 915 xfree(info); 916 xfree(lang); 917 packet_start(SSH2_MSG_USERAUTH_REQUEST); 918 packet_put_cstring(authctxt->server_user); 919 packet_put_cstring(authctxt->service); 920 packet_put_cstring(authctxt->method->name); 921 packet_put_char(1); /* additional info */ 922 snprintf(prompt, sizeof(prompt), 923 "Enter %.30s@%.128s's old password: ", 924 authctxt->server_user, host); 925 password = read_passphrase(prompt, 0); 926 packet_put_cstring(password); 927 memset(password, 0, strlen(password)); 928 xfree(password); 929 password = NULL; 930 while (password == NULL) { 931 snprintf(prompt, sizeof(prompt), 932 "Enter %.30s@%.128s's new password: ", 933 authctxt->server_user, host); 934 password = read_passphrase(prompt, RP_ALLOW_EOF); 935 if (password == NULL) { 936 /* bail out */ 937 return; 938 } 939 snprintf(prompt, sizeof(prompt), 940 "Retype %.30s@%.128s's new password: ", 941 authctxt->server_user, host); 942 retype = read_passphrase(prompt, 0); 943 if (strcmp(password, retype) != 0) { 944 memset(password, 0, strlen(password)); 945 xfree(password); 946 logit("Mismatch; try again, EOF to quit."); 947 password = NULL; 948 } 949 memset(retype, 0, strlen(retype)); 950 xfree(retype); 951 } 952 packet_put_cstring(password); 953 memset(password, 0, strlen(password)); 954 xfree(password); 955 packet_add_padding(64); 956 packet_send(); 957 958 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 959 &input_userauth_passwd_changereq); 960 } 961 962 #ifdef JPAKE 963 static char * 964 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 965 { 966 /* OpenBSD crypt(3) handles all of these */ 967 if (strcmp(crypt_scheme, "crypt") == 0 || 968 strcmp(crypt_scheme, "bcrypt") == 0 || 969 strcmp(crypt_scheme, "md5crypt") == 0 || 970 strcmp(crypt_scheme, "crypt-extended") == 0) 971 return xstrdup(crypt(password, salt)); 972 error("%s: unsupported password encryption scheme \"%.100s\"", 973 __func__, crypt_scheme); 974 return NULL; 975 } 976 977 static BIGNUM * 978 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 979 const char *salt) 980 { 981 char prompt[256], *password, *crypted; 982 u_char *secret; 983 u_int secret_len; 984 BIGNUM *ret; 985 986 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 987 authctxt->server_user, authctxt->host); 988 password = read_passphrase(prompt, 0); 989 990 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 991 logit("Disabling %s authentication", authctxt->method->name); 992 authctxt->method->enabled = NULL; 993 /* Continue with an empty password to fail gracefully */ 994 crypted = xstrdup(""); 995 } 996 997 #ifdef JPAKE_DEBUG 998 debug3("%s: salt = %s", __func__, salt); 999 debug3("%s: scheme = %s", __func__, crypt_scheme); 1000 debug3("%s: crypted = %s", __func__, crypted); 1001 #endif 1002 1003 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 1004 &secret, &secret_len) != 0) 1005 fatal("%s: hash_buffer", __func__); 1006 1007 bzero(password, strlen(password)); 1008 bzero(crypted, strlen(crypted)); 1009 xfree(password); 1010 xfree(crypted); 1011 1012 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 1013 fatal("%s: BN_bin2bn (secret)", __func__); 1014 bzero(secret, secret_len); 1015 xfree(secret); 1016 1017 return ret; 1018 } 1019 1020 /* ARGSUSED */ 1021 void 1022 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 1023 { 1024 Authctxt *authctxt = ctxt; 1025 struct jpake_ctx *pctx = authctxt->methoddata; 1026 u_char *x3_proof, *x4_proof, *x2_s_proof; 1027 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 1028 char *crypt_scheme, *salt; 1029 1030 /* Disable this message */ 1031 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 1032 1033 if ((pctx->g_x3 = BN_new()) == NULL || 1034 (pctx->g_x4 = BN_new()) == NULL) 1035 fatal("%s: BN_new", __func__); 1036 1037 /* Fetch step 1 values */ 1038 crypt_scheme = packet_get_string(NULL); 1039 salt = packet_get_string(NULL); 1040 pctx->server_id = packet_get_string(&pctx->server_id_len); 1041 packet_get_bignum2(pctx->g_x3); 1042 packet_get_bignum2(pctx->g_x4); 1043 x3_proof = packet_get_string(&x3_proof_len); 1044 x4_proof = packet_get_string(&x4_proof_len); 1045 packet_check_eom(); 1046 1047 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1048 1049 /* Obtain password and derive secret */ 1050 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1051 bzero(crypt_scheme, strlen(crypt_scheme)); 1052 bzero(salt, strlen(salt)); 1053 xfree(crypt_scheme); 1054 xfree(salt); 1055 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1056 1057 /* Calculate step 2 values */ 1058 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1059 pctx->g_x3, pctx->g_x4, pctx->x2, 1060 pctx->server_id, pctx->server_id_len, 1061 pctx->client_id, pctx->client_id_len, 1062 x3_proof, x3_proof_len, 1063 x4_proof, x4_proof_len, 1064 &pctx->a, 1065 &x2_s_proof, &x2_s_proof_len); 1066 1067 bzero(x3_proof, x3_proof_len); 1068 bzero(x4_proof, x4_proof_len); 1069 xfree(x3_proof); 1070 xfree(x4_proof); 1071 1072 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1073 1074 /* Send values for step 2 */ 1075 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1076 packet_put_bignum2(pctx->a); 1077 packet_put_string(x2_s_proof, x2_s_proof_len); 1078 packet_send(); 1079 1080 bzero(x2_s_proof, x2_s_proof_len); 1081 xfree(x2_s_proof); 1082 1083 /* Expect step 2 packet from peer */ 1084 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1085 input_userauth_jpake_server_step2); 1086 } 1087 1088 /* ARGSUSED */ 1089 void 1090 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1091 { 1092 Authctxt *authctxt = ctxt; 1093 struct jpake_ctx *pctx = authctxt->methoddata; 1094 u_char *x4_s_proof; 1095 u_int x4_s_proof_len; 1096 1097 /* Disable this message */ 1098 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1099 1100 if ((pctx->b = BN_new()) == NULL) 1101 fatal("%s: BN_new", __func__); 1102 1103 /* Fetch step 2 values */ 1104 packet_get_bignum2(pctx->b); 1105 x4_s_proof = packet_get_string(&x4_s_proof_len); 1106 packet_check_eom(); 1107 1108 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1109 1110 /* Derive shared key and calculate confirmation hash */ 1111 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1112 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1113 pctx->client_id, pctx->client_id_len, 1114 pctx->server_id, pctx->server_id_len, 1115 session_id2, session_id2_len, 1116 x4_s_proof, x4_s_proof_len, 1117 &pctx->k, 1118 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1119 1120 bzero(x4_s_proof, x4_s_proof_len); 1121 xfree(x4_s_proof); 1122 1123 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1124 1125 /* Send key confirmation proof */ 1126 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1127 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1128 packet_send(); 1129 1130 /* Expect confirmation from peer */ 1131 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1132 input_userauth_jpake_server_confirm); 1133 } 1134 1135 /* ARGSUSED */ 1136 void 1137 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1138 { 1139 Authctxt *authctxt = ctxt; 1140 struct jpake_ctx *pctx = authctxt->methoddata; 1141 1142 /* Disable this message */ 1143 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1144 1145 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1146 packet_check_eom(); 1147 1148 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1149 1150 /* Verify expected confirmation hash */ 1151 if (jpake_check_confirm(pctx->k, 1152 pctx->server_id, pctx->server_id_len, 1153 session_id2, session_id2_len, 1154 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1155 debug("%s: %s success", __func__, authctxt->method->name); 1156 else { 1157 debug("%s: confirmation mismatch", __func__); 1158 /* XXX stash this so if auth succeeds then we can warn/kill */ 1159 } 1160 1161 userauth_jpake_cleanup(authctxt); 1162 } 1163 #endif /* JPAKE */ 1164 1165 static int 1166 identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1167 u_char *data, u_int datalen) 1168 { 1169 Key *prv; 1170 int ret; 1171 1172 /* the agent supports this key */ 1173 if (id->ac) 1174 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1175 data, datalen)); 1176 /* 1177 * we have already loaded the private key or 1178 * the private key is stored in external hardware 1179 */ 1180 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1181 return (key_sign(id->key, sigp, lenp, data, datalen)); 1182 /* load the private key from the file */ 1183 if ((prv = load_identity_file(id->filename)) == NULL) 1184 return (-1); 1185 ret = key_sign(prv, sigp, lenp, data, datalen); 1186 key_free(prv); 1187 return (ret); 1188 } 1189 1190 static int 1191 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1192 { 1193 Buffer b; 1194 u_char *blob, *signature; 1195 u_int bloblen, slen; 1196 u_int skip = 0; 1197 int ret = -1; 1198 int have_sig = 1; 1199 char *fp; 1200 1201 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1202 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1203 xfree(fp); 1204 1205 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1206 /* we cannot handle this key */ 1207 debug3("sign_and_send_pubkey: cannot handle key"); 1208 return 0; 1209 } 1210 /* data to be signed */ 1211 buffer_init(&b); 1212 if (datafellows & SSH_OLD_SESSIONID) { 1213 buffer_append(&b, session_id2, session_id2_len); 1214 skip = session_id2_len; 1215 } else { 1216 buffer_put_string(&b, session_id2, session_id2_len); 1217 skip = buffer_len(&b); 1218 } 1219 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1220 buffer_put_cstring(&b, authctxt->server_user); 1221 buffer_put_cstring(&b, 1222 datafellows & SSH_BUG_PKSERVICE ? 1223 "ssh-userauth" : 1224 authctxt->service); 1225 if (datafellows & SSH_BUG_PKAUTH) { 1226 buffer_put_char(&b, have_sig); 1227 } else { 1228 buffer_put_cstring(&b, authctxt->method->name); 1229 buffer_put_char(&b, have_sig); 1230 buffer_put_cstring(&b, key_ssh_name(id->key)); 1231 } 1232 buffer_put_string(&b, blob, bloblen); 1233 1234 /* generate signature */ 1235 ret = identity_sign(id, &signature, &slen, 1236 buffer_ptr(&b), buffer_len(&b)); 1237 if (ret == -1) { 1238 xfree(blob); 1239 buffer_free(&b); 1240 return 0; 1241 } 1242 #ifdef DEBUG_PK 1243 buffer_dump(&b); 1244 #endif 1245 if (datafellows & SSH_BUG_PKSERVICE) { 1246 buffer_clear(&b); 1247 buffer_append(&b, session_id2, session_id2_len); 1248 skip = session_id2_len; 1249 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1250 buffer_put_cstring(&b, authctxt->server_user); 1251 buffer_put_cstring(&b, authctxt->service); 1252 buffer_put_cstring(&b, authctxt->method->name); 1253 buffer_put_char(&b, have_sig); 1254 if (!(datafellows & SSH_BUG_PKAUTH)) 1255 buffer_put_cstring(&b, key_ssh_name(id->key)); 1256 buffer_put_string(&b, blob, bloblen); 1257 } 1258 xfree(blob); 1259 1260 /* append signature */ 1261 buffer_put_string(&b, signature, slen); 1262 xfree(signature); 1263 1264 /* skip session id and packet type */ 1265 if (buffer_len(&b) < skip + 1) 1266 fatal("userauth_pubkey: internal error"); 1267 buffer_consume(&b, skip + 1); 1268 1269 /* put remaining data from buffer into packet */ 1270 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1271 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1272 buffer_free(&b); 1273 packet_send(); 1274 1275 return 1; 1276 } 1277 1278 static int 1279 send_pubkey_test(Authctxt *authctxt, Identity *id) 1280 { 1281 u_char *blob; 1282 u_int bloblen, have_sig = 0; 1283 1284 debug3("send_pubkey_test"); 1285 1286 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1287 /* we cannot handle this key */ 1288 debug3("send_pubkey_test: cannot handle key"); 1289 return 0; 1290 } 1291 /* register callback for USERAUTH_PK_OK message */ 1292 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1293 1294 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1295 packet_put_cstring(authctxt->server_user); 1296 packet_put_cstring(authctxt->service); 1297 packet_put_cstring(authctxt->method->name); 1298 packet_put_char(have_sig); 1299 if (!(datafellows & SSH_BUG_PKAUTH)) 1300 packet_put_cstring(key_ssh_name(id->key)); 1301 packet_put_string(blob, bloblen); 1302 xfree(blob); 1303 packet_send(); 1304 return 1; 1305 } 1306 1307 static Key * 1308 load_identity_file(char *filename) 1309 { 1310 Key *private; 1311 char prompt[300], *passphrase; 1312 int perm_ok = 0, quit, i; 1313 struct stat st; 1314 1315 if (stat(filename, &st) < 0) { 1316 debug3("no such identity: %s", filename); 1317 return NULL; 1318 } 1319 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1320 if (!perm_ok) 1321 return NULL; 1322 if (private == NULL) { 1323 if (options.batch_mode) 1324 return NULL; 1325 snprintf(prompt, sizeof prompt, 1326 "Enter passphrase for key '%.100s': ", filename); 1327 for (i = 0; i < options.number_of_password_prompts; i++) { 1328 passphrase = read_passphrase(prompt, 0); 1329 if (strcmp(passphrase, "") != 0) { 1330 private = key_load_private_type(KEY_UNSPEC, 1331 filename, passphrase, NULL, NULL); 1332 quit = 0; 1333 } else { 1334 debug2("no passphrase given, try next key"); 1335 quit = 1; 1336 } 1337 memset(passphrase, 0, strlen(passphrase)); 1338 xfree(passphrase); 1339 if (private != NULL || quit) 1340 break; 1341 debug2("bad passphrase given, try again..."); 1342 } 1343 } 1344 return private; 1345 } 1346 1347 /* 1348 * try keys in the following order: 1349 * 1. agent keys that are found in the config file 1350 * 2. other agent keys 1351 * 3. keys that are only listed in the config file 1352 */ 1353 static void 1354 pubkey_prepare(Authctxt *authctxt) 1355 { 1356 Identity *id; 1357 Idlist agent, files, *preferred; 1358 Key *key; 1359 AuthenticationConnection *ac; 1360 char *comment; 1361 int i, found; 1362 1363 TAILQ_INIT(&agent); /* keys from the agent */ 1364 TAILQ_INIT(&files); /* keys from the config file */ 1365 preferred = &authctxt->keys; 1366 TAILQ_INIT(preferred); /* preferred order of keys */ 1367 1368 /* list of keys stored in the filesystem */ 1369 for (i = 0; i < options.num_identity_files; i++) { 1370 key = options.identity_keys[i]; 1371 if (key && key->type == KEY_RSA1) 1372 continue; 1373 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1374 continue; 1375 options.identity_keys[i] = NULL; 1376 id = xcalloc(1, sizeof(*id)); 1377 id->key = key; 1378 id->filename = xstrdup(options.identity_files[i]); 1379 TAILQ_INSERT_TAIL(&files, id, next); 1380 } 1381 /* list of keys supported by the agent */ 1382 if ((ac = ssh_get_authentication_connection())) { 1383 for (key = ssh_get_first_identity(ac, &comment, 2); 1384 key != NULL; 1385 key = ssh_get_next_identity(ac, &comment, 2)) { 1386 found = 0; 1387 TAILQ_FOREACH(id, &files, next) { 1388 /* agent keys from the config file are preferred */ 1389 if (key_equal(key, id->key)) { 1390 key_free(key); 1391 xfree(comment); 1392 TAILQ_REMOVE(&files, id, next); 1393 TAILQ_INSERT_TAIL(preferred, id, next); 1394 id->ac = ac; 1395 found = 1; 1396 break; 1397 } 1398 } 1399 if (!found && !options.identities_only) { 1400 id = xcalloc(1, sizeof(*id)); 1401 id->key = key; 1402 id->filename = comment; 1403 id->ac = ac; 1404 TAILQ_INSERT_TAIL(&agent, id, next); 1405 } 1406 } 1407 /* append remaining agent keys */ 1408 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1409 TAILQ_REMOVE(&agent, id, next); 1410 TAILQ_INSERT_TAIL(preferred, id, next); 1411 } 1412 authctxt->agent = ac; 1413 } 1414 /* append remaining keys from the config file */ 1415 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1416 TAILQ_REMOVE(&files, id, next); 1417 TAILQ_INSERT_TAIL(preferred, id, next); 1418 } 1419 TAILQ_FOREACH(id, preferred, next) { 1420 debug2("key: %s (%p)", id->filename, id->key); 1421 } 1422 } 1423 1424 static void 1425 pubkey_cleanup(Authctxt *authctxt) 1426 { 1427 Identity *id; 1428 1429 if (authctxt->agent != NULL) 1430 ssh_close_authentication_connection(authctxt->agent); 1431 for (id = TAILQ_FIRST(&authctxt->keys); id; 1432 id = TAILQ_FIRST(&authctxt->keys)) { 1433 TAILQ_REMOVE(&authctxt->keys, id, next); 1434 if (id->key) 1435 key_free(id->key); 1436 if (id->filename) 1437 xfree(id->filename); 1438 xfree(id); 1439 } 1440 } 1441 1442 int 1443 userauth_pubkey(Authctxt *authctxt) 1444 { 1445 Identity *id; 1446 int sent = 0; 1447 1448 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1449 if (id->tried++) 1450 return (0); 1451 /* move key to the end of the queue */ 1452 TAILQ_REMOVE(&authctxt->keys, id, next); 1453 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1454 /* 1455 * send a test message if we have the public key. for 1456 * encrypted keys we cannot do this and have to load the 1457 * private key instead 1458 */ 1459 if (id->key && id->key->type != KEY_RSA1) { 1460 debug("Offering %s public key: %s", key_type(id->key), 1461 id->filename); 1462 sent = send_pubkey_test(authctxt, id); 1463 } else if (id->key == NULL) { 1464 debug("Trying private key: %s", id->filename); 1465 id->key = load_identity_file(id->filename); 1466 if (id->key != NULL) { 1467 id->isprivate = 1; 1468 sent = sign_and_send_pubkey(authctxt, id); 1469 key_free(id->key); 1470 id->key = NULL; 1471 } 1472 } 1473 if (sent) 1474 return (sent); 1475 } 1476 return (0); 1477 } 1478 1479 /* 1480 * Send userauth request message specifying keyboard-interactive method. 1481 */ 1482 int 1483 userauth_kbdint(Authctxt *authctxt) 1484 { 1485 static int attempt = 0; 1486 1487 if (attempt++ >= options.number_of_password_prompts) 1488 return 0; 1489 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1490 if (attempt > 1 && !authctxt->info_req_seen) { 1491 debug3("userauth_kbdint: disable: no info_req_seen"); 1492 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1493 return 0; 1494 } 1495 1496 debug2("userauth_kbdint"); 1497 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1498 packet_put_cstring(authctxt->server_user); 1499 packet_put_cstring(authctxt->service); 1500 packet_put_cstring(authctxt->method->name); 1501 packet_put_cstring(""); /* lang */ 1502 packet_put_cstring(options.kbd_interactive_devices ? 1503 options.kbd_interactive_devices : ""); 1504 packet_send(); 1505 1506 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1507 return 1; 1508 } 1509 1510 /* 1511 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1512 */ 1513 void 1514 input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1515 { 1516 Authctxt *authctxt = ctxt; 1517 char *name, *inst, *lang, *prompt, *response; 1518 u_int num_prompts, i; 1519 int echo = 0; 1520 1521 debug2("input_userauth_info_req"); 1522 1523 if (authctxt == NULL) 1524 fatal("input_userauth_info_req: no authentication context"); 1525 1526 authctxt->info_req_seen = 1; 1527 1528 name = packet_get_string(NULL); 1529 inst = packet_get_string(NULL); 1530 lang = packet_get_string(NULL); 1531 if (strlen(name) > 0) 1532 logit("%s", name); 1533 if (strlen(inst) > 0) 1534 logit("%s", inst); 1535 xfree(name); 1536 xfree(inst); 1537 xfree(lang); 1538 1539 num_prompts = packet_get_int(); 1540 /* 1541 * Begin to build info response packet based on prompts requested. 1542 * We commit to providing the correct number of responses, so if 1543 * further on we run into a problem that prevents this, we have to 1544 * be sure and clean this up and send a correct error response. 1545 */ 1546 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1547 packet_put_int(num_prompts); 1548 1549 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1550 for (i = 0; i < num_prompts; i++) { 1551 prompt = packet_get_string(NULL); 1552 echo = packet_get_char(); 1553 1554 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1555 1556 packet_put_cstring(response); 1557 memset(response, 0, strlen(response)); 1558 xfree(response); 1559 xfree(prompt); 1560 } 1561 packet_check_eom(); /* done with parsing incoming message. */ 1562 1563 packet_add_padding(64); 1564 packet_send(); 1565 } 1566 1567 static int 1568 ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1569 u_char *data, u_int datalen) 1570 { 1571 Buffer b; 1572 struct stat st; 1573 pid_t pid; 1574 int to[2], from[2], status, version = 2; 1575 1576 debug2("ssh_keysign called"); 1577 1578 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1579 error("ssh_keysign: not installed: %s", strerror(errno)); 1580 return -1; 1581 } 1582 if (fflush(stdout) != 0) 1583 error("ssh_keysign: fflush: %s", strerror(errno)); 1584 if (pipe(to) < 0) { 1585 error("ssh_keysign: pipe: %s", strerror(errno)); 1586 return -1; 1587 } 1588 if (pipe(from) < 0) { 1589 error("ssh_keysign: pipe: %s", strerror(errno)); 1590 return -1; 1591 } 1592 if ((pid = fork()) < 0) { 1593 error("ssh_keysign: fork: %s", strerror(errno)); 1594 return -1; 1595 } 1596 if (pid == 0) { 1597 /* keep the socket on exec */ 1598 fcntl(packet_get_connection_in(), F_SETFD, 0); 1599 permanently_drop_suid(getuid()); 1600 close(from[0]); 1601 if (dup2(from[1], STDOUT_FILENO) < 0) 1602 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1603 close(to[1]); 1604 if (dup2(to[0], STDIN_FILENO) < 0) 1605 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1606 close(from[1]); 1607 close(to[0]); 1608 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1609 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1610 strerror(errno)); 1611 } 1612 close(from[1]); 1613 close(to[0]); 1614 1615 buffer_init(&b); 1616 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1617 buffer_put_string(&b, data, datalen); 1618 if (ssh_msg_send(to[1], version, &b) == -1) 1619 fatal("ssh_keysign: couldn't send request"); 1620 1621 if (ssh_msg_recv(from[0], &b) < 0) { 1622 error("ssh_keysign: no reply"); 1623 buffer_free(&b); 1624 return -1; 1625 } 1626 close(from[0]); 1627 close(to[1]); 1628 1629 while (waitpid(pid, &status, 0) < 0) 1630 if (errno != EINTR) 1631 break; 1632 1633 if (buffer_get_char(&b) != version) { 1634 error("ssh_keysign: bad version"); 1635 buffer_free(&b); 1636 return -1; 1637 } 1638 *sigp = buffer_get_string(&b, lenp); 1639 buffer_free(&b); 1640 1641 return 0; 1642 } 1643 1644 int 1645 userauth_hostbased(Authctxt *authctxt) 1646 { 1647 Key *private = NULL; 1648 Sensitive *sensitive = authctxt->sensitive; 1649 Buffer b; 1650 u_char *signature, *blob; 1651 char *chost, *pkalg, *p; 1652 const char *service; 1653 u_int blen, slen; 1654 int ok, i, found = 0; 1655 1656 /* check for a useful key */ 1657 for (i = 0; i < sensitive->nkeys; i++) { 1658 private = sensitive->keys[i]; 1659 if (private && private->type != KEY_RSA1) { 1660 found = 1; 1661 /* we take and free the key */ 1662 sensitive->keys[i] = NULL; 1663 break; 1664 } 1665 } 1666 if (!found) { 1667 debug("No more client hostkeys for hostbased authentication."); 1668 return 0; 1669 } 1670 if (key_to_blob(private, &blob, &blen) == 0) { 1671 key_free(private); 1672 return 0; 1673 } 1674 /* figure out a name for the client host */ 1675 p = get_local_name(packet_get_connection_in()); 1676 if (p == NULL) { 1677 error("userauth_hostbased: cannot get local ipaddr/name"); 1678 key_free(private); 1679 xfree(blob); 1680 return 0; 1681 } 1682 xasprintf(&chost, "%s.", p); 1683 debug2("userauth_hostbased: chost %s", chost); 1684 xfree(p); 1685 1686 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1687 authctxt->service; 1688 pkalg = xstrdup(key_ssh_name(private)); 1689 buffer_init(&b); 1690 /* construct data */ 1691 buffer_put_string(&b, session_id2, session_id2_len); 1692 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1693 buffer_put_cstring(&b, authctxt->server_user); 1694 buffer_put_cstring(&b, service); 1695 buffer_put_cstring(&b, authctxt->method->name); 1696 buffer_put_cstring(&b, pkalg); 1697 buffer_put_string(&b, blob, blen); 1698 buffer_put_cstring(&b, chost); 1699 buffer_put_cstring(&b, authctxt->local_user); 1700 #ifdef DEBUG_PK 1701 buffer_dump(&b); 1702 #endif 1703 if (sensitive->external_keysign) 1704 ok = ssh_keysign(private, &signature, &slen, 1705 buffer_ptr(&b), buffer_len(&b)); 1706 else 1707 ok = key_sign(private, &signature, &slen, 1708 buffer_ptr(&b), buffer_len(&b)); 1709 key_free(private); 1710 buffer_free(&b); 1711 if (ok != 0) { 1712 error("key_sign failed"); 1713 xfree(chost); 1714 xfree(pkalg); 1715 xfree(blob); 1716 return 0; 1717 } 1718 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1719 packet_put_cstring(authctxt->server_user); 1720 packet_put_cstring(authctxt->service); 1721 packet_put_cstring(authctxt->method->name); 1722 packet_put_cstring(pkalg); 1723 packet_put_string(blob, blen); 1724 packet_put_cstring(chost); 1725 packet_put_cstring(authctxt->local_user); 1726 packet_put_string(signature, slen); 1727 memset(signature, 's', slen); 1728 xfree(signature); 1729 xfree(chost); 1730 xfree(pkalg); 1731 xfree(blob); 1732 1733 packet_send(); 1734 return 1; 1735 } 1736 1737 #ifdef JPAKE 1738 int 1739 userauth_jpake(Authctxt *authctxt) 1740 { 1741 struct jpake_ctx *pctx; 1742 u_char *x1_proof, *x2_proof; 1743 u_int x1_proof_len, x2_proof_len; 1744 static int attempt = 0; /* XXX share with userauth_password's? */ 1745 1746 if (attempt++ >= options.number_of_password_prompts) 1747 return 0; 1748 if (attempt != 1) 1749 error("Permission denied, please try again."); 1750 1751 if (authctxt->methoddata != NULL) 1752 fatal("%s: authctxt->methoddata already set (%p)", 1753 __func__, authctxt->methoddata); 1754 1755 authctxt->methoddata = pctx = jpake_new(); 1756 1757 /* 1758 * Send request immediately, to get the protocol going while 1759 * we do the initial computations. 1760 */ 1761 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1762 packet_put_cstring(authctxt->server_user); 1763 packet_put_cstring(authctxt->service); 1764 packet_put_cstring(authctxt->method->name); 1765 packet_send(); 1766 packet_write_wait(); 1767 1768 jpake_step1(pctx->grp, 1769 &pctx->client_id, &pctx->client_id_len, 1770 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1771 &x1_proof, &x1_proof_len, 1772 &x2_proof, &x2_proof_len); 1773 1774 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1775 1776 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1777 packet_put_string(pctx->client_id, pctx->client_id_len); 1778 packet_put_bignum2(pctx->g_x1); 1779 packet_put_bignum2(pctx->g_x2); 1780 packet_put_string(x1_proof, x1_proof_len); 1781 packet_put_string(x2_proof, x2_proof_len); 1782 packet_send(); 1783 1784 bzero(x1_proof, x1_proof_len); 1785 bzero(x2_proof, x2_proof_len); 1786 xfree(x1_proof); 1787 xfree(x2_proof); 1788 1789 /* Expect step 1 packet from peer */ 1790 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1791 input_userauth_jpake_server_step1); 1792 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1793 &input_userauth_success_unexpected); 1794 1795 return 1; 1796 } 1797 1798 void 1799 userauth_jpake_cleanup(Authctxt *authctxt) 1800 { 1801 debug3("%s: clean up", __func__); 1802 if (authctxt->methoddata != NULL) { 1803 jpake_free(authctxt->methoddata); 1804 authctxt->methoddata = NULL; 1805 } 1806 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1807 } 1808 #endif /* JPAKE */ 1809 1810 /* find auth method */ 1811 1812 /* 1813 * given auth method name, if configurable options permit this method fill 1814 * in auth_ident field and return true, otherwise return false. 1815 */ 1816 static int 1817 authmethod_is_enabled(Authmethod *method) 1818 { 1819 if (method == NULL) 1820 return 0; 1821 /* return false if options indicate this method is disabled */ 1822 if (method->enabled == NULL || *method->enabled == 0) 1823 return 0; 1824 /* return false if batch mode is enabled but method needs interactive mode */ 1825 if (method->batch_flag != NULL && *method->batch_flag != 0) 1826 return 0; 1827 return 1; 1828 } 1829 1830 static Authmethod * 1831 authmethod_lookup(const char *name) 1832 { 1833 Authmethod *method = NULL; 1834 if (name != NULL) 1835 for (method = authmethods; method->name != NULL; method++) 1836 if (strcmp(name, method->name) == 0) 1837 return method; 1838 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1839 return NULL; 1840 } 1841 1842 /* XXX internal state */ 1843 static Authmethod *current = NULL; 1844 static char *supported = NULL; 1845 static char *preferred = NULL; 1846 1847 /* 1848 * Given the authentication method list sent by the server, return the 1849 * next method we should try. If the server initially sends a nil list, 1850 * use a built-in default list. 1851 */ 1852 static Authmethod * 1853 authmethod_get(char *authlist) 1854 { 1855 char *name = NULL; 1856 u_int next; 1857 1858 /* Use a suitable default if we're passed a nil list. */ 1859 if (authlist == NULL || strlen(authlist) == 0) 1860 authlist = options.preferred_authentications; 1861 1862 if (supported == NULL || strcmp(authlist, supported) != 0) { 1863 debug3("start over, passed a different list %s", authlist); 1864 if (supported != NULL) 1865 xfree(supported); 1866 supported = xstrdup(authlist); 1867 preferred = options.preferred_authentications; 1868 debug3("preferred %s", preferred); 1869 current = NULL; 1870 } else if (current != NULL && authmethod_is_enabled(current)) 1871 return current; 1872 1873 for (;;) { 1874 if ((name = match_list(preferred, supported, &next)) == NULL) { 1875 debug("No more authentication methods to try."); 1876 current = NULL; 1877 return NULL; 1878 } 1879 preferred += next; 1880 debug3("authmethod_lookup %s", name); 1881 debug3("remaining preferred: %s", preferred); 1882 if ((current = authmethod_lookup(name)) != NULL && 1883 authmethod_is_enabled(current)) { 1884 debug3("authmethod_is_enabled %s", name); 1885 debug("Next authentication method: %s", name); 1886 xfree(name); 1887 return current; 1888 } 1889 } 1890 } 1891 1892 static char * 1893 authmethods_get(void) 1894 { 1895 Authmethod *method = NULL; 1896 Buffer b; 1897 char *list; 1898 1899 buffer_init(&b); 1900 for (method = authmethods; method->name != NULL; method++) { 1901 if (authmethod_is_enabled(method)) { 1902 if (buffer_len(&b) > 0) 1903 buffer_append(&b, ",", 1); 1904 buffer_append(&b, method->name, strlen(method->name)); 1905 } 1906 } 1907 buffer_append(&b, "\0", 1); 1908 list = xstrdup(buffer_ptr(&b)); 1909 buffer_free(&b); 1910 return list; 1911 } 1912 1913