1 /* $OpenBSD: sshconnect2.c,v 1.193 2013/03/05 20:16:09 markus 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 int userprovided; 246 }; 247 TAILQ_HEAD(idlist, identity); 248 249 struct Authctxt { 250 const char *server_user; 251 const char *local_user; 252 const char *host; 253 const char *service; 254 Authmethod *method; 255 sig_atomic_t success; 256 char *authlist; 257 /* pubkey */ 258 Idlist keys; 259 AuthenticationConnection *agent; 260 /* hostbased */ 261 Sensitive *sensitive; 262 /* kbd-interactive */ 263 int info_req_seen; 264 /* generic */ 265 void *methoddata; 266 }; 267 struct Authmethod { 268 char *name; /* string to compare against server's list */ 269 int (*userauth)(Authctxt *authctxt); 270 void (*cleanup)(Authctxt *authctxt); 271 int *enabled; /* flag in option struct that enables method */ 272 int *batch_flag; /* flag in option struct that disables method */ 273 }; 274 275 void input_userauth_success(int, u_int32_t, void *); 276 void input_userauth_success_unexpected(int, u_int32_t, void *); 277 void input_userauth_failure(int, u_int32_t, void *); 278 void input_userauth_banner(int, u_int32_t, void *); 279 void input_userauth_error(int, u_int32_t, void *); 280 void input_userauth_info_req(int, u_int32_t, void *); 281 void input_userauth_pk_ok(int, u_int32_t, void *); 282 void input_userauth_passwd_changereq(int, u_int32_t, void *); 283 void input_userauth_jpake_server_step1(int, u_int32_t, void *); 284 void input_userauth_jpake_server_step2(int, u_int32_t, void *); 285 void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 286 287 int userauth_none(Authctxt *); 288 int userauth_pubkey(Authctxt *); 289 int userauth_passwd(Authctxt *); 290 int userauth_kbdint(Authctxt *); 291 int userauth_hostbased(Authctxt *); 292 int userauth_jpake(Authctxt *); 293 294 void userauth_jpake_cleanup(Authctxt *); 295 296 #ifdef GSSAPI 297 int userauth_gssapi(Authctxt *authctxt); 298 void input_gssapi_response(int type, u_int32_t, void *); 299 void input_gssapi_token(int type, u_int32_t, void *); 300 void input_gssapi_hash(int type, u_int32_t, void *); 301 void input_gssapi_error(int, u_int32_t, void *); 302 void input_gssapi_errtok(int, u_int32_t, void *); 303 #endif 304 305 void userauth(Authctxt *, char *); 306 307 static int sign_and_send_pubkey(Authctxt *, Identity *); 308 static void pubkey_prepare(Authctxt *); 309 static void pubkey_cleanup(Authctxt *); 310 static Key *load_identity_file(char *, int); 311 312 static Authmethod *authmethod_get(char *authlist); 313 static Authmethod *authmethod_lookup(const char *name); 314 static char *authmethods_get(void); 315 316 Authmethod authmethods[] = { 317 #ifdef GSSAPI 318 {"gssapi-with-mic", 319 userauth_gssapi, 320 NULL, 321 &options.gss_authentication, 322 NULL}, 323 #endif 324 {"hostbased", 325 userauth_hostbased, 326 NULL, 327 &options.hostbased_authentication, 328 NULL}, 329 {"publickey", 330 userauth_pubkey, 331 NULL, 332 &options.pubkey_authentication, 333 NULL}, 334 #ifdef JPAKE 335 {"jpake-01@openssh.com", 336 userauth_jpake, 337 userauth_jpake_cleanup, 338 &options.zero_knowledge_password_authentication, 339 &options.batch_mode}, 340 #endif 341 {"keyboard-interactive", 342 userauth_kbdint, 343 NULL, 344 &options.kbd_interactive_authentication, 345 &options.batch_mode}, 346 {"password", 347 userauth_passwd, 348 NULL, 349 &options.password_authentication, 350 &options.batch_mode}, 351 {"none", 352 userauth_none, 353 NULL, 354 NULL, 355 NULL}, 356 {NULL, NULL, NULL, NULL, NULL} 357 }; 358 359 void 360 ssh_userauth2(const char *local_user, const char *server_user, char *host, 361 Sensitive *sensitive) 362 { 363 Authctxt authctxt; 364 int type; 365 366 if (options.challenge_response_authentication) 367 options.kbd_interactive_authentication = 1; 368 369 packet_start(SSH2_MSG_SERVICE_REQUEST); 370 packet_put_cstring("ssh-userauth"); 371 packet_send(); 372 debug("SSH2_MSG_SERVICE_REQUEST sent"); 373 packet_write_wait(); 374 type = packet_read(); 375 if (type != SSH2_MSG_SERVICE_ACCEPT) 376 fatal("Server denied authentication request: %d", type); 377 if (packet_remaining() > 0) { 378 char *reply = packet_get_string(NULL); 379 debug2("service_accept: %s", reply); 380 xfree(reply); 381 } else { 382 debug2("buggy server: service_accept w/o service"); 383 } 384 packet_check_eom(); 385 debug("SSH2_MSG_SERVICE_ACCEPT received"); 386 387 if (options.preferred_authentications == NULL) 388 options.preferred_authentications = authmethods_get(); 389 390 /* setup authentication context */ 391 memset(&authctxt, 0, sizeof(authctxt)); 392 pubkey_prepare(&authctxt); 393 authctxt.server_user = server_user; 394 authctxt.local_user = local_user; 395 authctxt.host = host; 396 authctxt.service = "ssh-connection"; /* service name */ 397 authctxt.success = 0; 398 authctxt.method = authmethod_lookup("none"); 399 authctxt.authlist = NULL; 400 authctxt.methoddata = NULL; 401 authctxt.sensitive = sensitive; 402 authctxt.info_req_seen = 0; 403 if (authctxt.method == NULL) 404 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 405 406 /* initial userauth request */ 407 userauth_none(&authctxt); 408 409 dispatch_init(&input_userauth_error); 410 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 411 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 412 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 413 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 414 415 pubkey_cleanup(&authctxt); 416 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 417 418 debug("Authentication succeeded (%s).", authctxt.method->name); 419 } 420 421 void 422 userauth(Authctxt *authctxt, char *authlist) 423 { 424 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 425 authctxt->method->cleanup(authctxt); 426 427 if (authctxt->methoddata) { 428 xfree(authctxt->methoddata); 429 authctxt->methoddata = NULL; 430 } 431 if (authlist == NULL) { 432 authlist = authctxt->authlist; 433 } else { 434 if (authctxt->authlist) 435 xfree(authctxt->authlist); 436 authctxt->authlist = authlist; 437 } 438 for (;;) { 439 Authmethod *method = authmethod_get(authlist); 440 if (method == NULL) 441 fatal("Permission denied (%s).", authlist); 442 authctxt->method = method; 443 444 /* reset the per method handler */ 445 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 446 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 447 448 /* and try new method */ 449 if (method->userauth(authctxt) != 0) { 450 debug2("we sent a %s packet, wait for reply", method->name); 451 break; 452 } else { 453 debug2("we did not send a packet, disable method"); 454 method->enabled = NULL; 455 } 456 } 457 } 458 459 /* ARGSUSED */ 460 void 461 input_userauth_error(int type, u_int32_t seq, void *ctxt) 462 { 463 fatal("input_userauth_error: bad message during authentication: " 464 "type %d", type); 465 } 466 467 /* ARGSUSED */ 468 void 469 input_userauth_banner(int type, u_int32_t seq, void *ctxt) 470 { 471 char *msg, *raw, *lang; 472 u_int len; 473 474 debug3("input_userauth_banner"); 475 raw = packet_get_string(&len); 476 lang = packet_get_string(NULL); 477 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 478 if (len > 65536) 479 len = 65536; 480 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 481 strnvis(msg, raw, len * 4 + 1, VIS_SAFE|VIS_OCTAL|VIS_NOSLASH); 482 fprintf(stderr, "%s", msg); 483 xfree(msg); 484 } 485 xfree(raw); 486 xfree(lang); 487 } 488 489 /* ARGSUSED */ 490 void 491 input_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 if (authctxt->authlist) { 498 xfree(authctxt->authlist); 499 authctxt->authlist = NULL; 500 } 501 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 502 authctxt->method->cleanup(authctxt); 503 if (authctxt->methoddata) { 504 xfree(authctxt->methoddata); 505 authctxt->methoddata = NULL; 506 } 507 authctxt->success = 1; /* break out */ 508 } 509 510 void 511 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 512 { 513 Authctxt *authctxt = ctxt; 514 515 if (authctxt == NULL) 516 fatal("%s: no authentication context", __func__); 517 518 fatal("Unexpected authentication success during %s.", 519 authctxt->method->name); 520 } 521 522 /* ARGSUSED */ 523 void 524 input_userauth_failure(int type, u_int32_t seq, void *ctxt) 525 { 526 Authctxt *authctxt = ctxt; 527 char *authlist = NULL; 528 int partial; 529 530 if (authctxt == NULL) 531 fatal("input_userauth_failure: no authentication context"); 532 533 authlist = packet_get_string(NULL); 534 partial = packet_get_char(); 535 packet_check_eom(); 536 537 if (partial != 0) { 538 logit("Authenticated with partial success."); 539 /* reset state */ 540 pubkey_cleanup(authctxt); 541 pubkey_prepare(authctxt); 542 } 543 debug("Authentications that can continue: %s", authlist); 544 545 userauth(authctxt, authlist); 546 } 547 548 /* ARGSUSED */ 549 void 550 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 551 { 552 Authctxt *authctxt = ctxt; 553 Key *key = NULL; 554 Identity *id = NULL; 555 Buffer b; 556 int pktype, sent = 0; 557 u_int alen, blen; 558 char *pkalg, *fp; 559 u_char *pkblob; 560 561 if (authctxt == NULL) 562 fatal("input_userauth_pk_ok: no authentication context"); 563 if (datafellows & SSH_BUG_PKOK) { 564 /* this is similar to SSH_BUG_PKAUTH */ 565 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 566 pkblob = packet_get_string(&blen); 567 buffer_init(&b); 568 buffer_append(&b, pkblob, blen); 569 pkalg = buffer_get_string(&b, &alen); 570 buffer_free(&b); 571 } else { 572 pkalg = packet_get_string(&alen); 573 pkblob = packet_get_string(&blen); 574 } 575 packet_check_eom(); 576 577 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 578 579 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 580 debug("unknown pkalg %s", pkalg); 581 goto done; 582 } 583 if ((key = key_from_blob(pkblob, blen)) == NULL) { 584 debug("no key from blob. pkalg %s", pkalg); 585 goto done; 586 } 587 if (key->type != pktype) { 588 error("input_userauth_pk_ok: type mismatch " 589 "for decoded key (received %d, expected %d)", 590 key->type, pktype); 591 goto done; 592 } 593 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 594 debug2("input_userauth_pk_ok: fp %s", fp); 595 xfree(fp); 596 597 /* 598 * search keys in the reverse order, because last candidate has been 599 * moved to the end of the queue. this also avoids confusion by 600 * duplicate keys 601 */ 602 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 603 if (key_equal(key, id->key)) { 604 sent = sign_and_send_pubkey(authctxt, id); 605 break; 606 } 607 } 608 done: 609 if (key != NULL) 610 key_free(key); 611 xfree(pkalg); 612 xfree(pkblob); 613 614 /* try another method if we did not send a packet */ 615 if (sent == 0) 616 userauth(authctxt, NULL); 617 } 618 619 #ifdef GSSAPI 620 int 621 userauth_gssapi(Authctxt *authctxt) 622 { 623 Gssctxt *gssctxt = NULL; 624 static gss_OID_set gss_supported = NULL; 625 static u_int mech = 0; 626 OM_uint32 min; 627 int ok = 0; 628 629 /* Try one GSSAPI method at a time, rather than sending them all at 630 * once. */ 631 632 if (gss_supported == NULL) 633 gss_indicate_mechs(&min, &gss_supported); 634 635 /* Check to see if the mechanism is usable before we offer it */ 636 while (mech < gss_supported->count && !ok) { 637 /* My DER encoding requires length<128 */ 638 if (gss_supported->elements[mech].length < 128 && 639 ssh_gssapi_check_mechanism(&gssctxt, 640 &gss_supported->elements[mech], authctxt->host)) { 641 ok = 1; /* Mechanism works */ 642 } else { 643 mech++; 644 } 645 } 646 647 if (!ok) 648 return 0; 649 650 authctxt->methoddata=(void *)gssctxt; 651 652 packet_start(SSH2_MSG_USERAUTH_REQUEST); 653 packet_put_cstring(authctxt->server_user); 654 packet_put_cstring(authctxt->service); 655 packet_put_cstring(authctxt->method->name); 656 657 packet_put_int(1); 658 659 packet_put_int((gss_supported->elements[mech].length) + 2); 660 packet_put_char(SSH_GSS_OIDTYPE); 661 packet_put_char(gss_supported->elements[mech].length); 662 packet_put_raw(gss_supported->elements[mech].elements, 663 gss_supported->elements[mech].length); 664 665 packet_send(); 666 667 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 668 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 669 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 670 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 671 672 mech++; /* Move along to next candidate */ 673 674 return 1; 675 } 676 677 static OM_uint32 678 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 679 { 680 Authctxt *authctxt = ctxt; 681 Gssctxt *gssctxt = authctxt->methoddata; 682 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 683 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 684 gss_buffer_desc gssbuf; 685 OM_uint32 status, ms, flags; 686 Buffer b; 687 688 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 689 recv_tok, &send_tok, &flags); 690 691 if (send_tok.length > 0) { 692 if (GSS_ERROR(status)) 693 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 694 else 695 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 696 697 packet_put_string(send_tok.value, send_tok.length); 698 packet_send(); 699 gss_release_buffer(&ms, &send_tok); 700 } 701 702 if (status == GSS_S_COMPLETE) { 703 /* send either complete or MIC, depending on mechanism */ 704 if (!(flags & GSS_C_INTEG_FLAG)) { 705 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 706 packet_send(); 707 } else { 708 ssh_gssapi_buildmic(&b, authctxt->server_user, 709 authctxt->service, "gssapi-with-mic"); 710 711 gssbuf.value = buffer_ptr(&b); 712 gssbuf.length = buffer_len(&b); 713 714 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 715 716 if (!GSS_ERROR(status)) { 717 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 718 packet_put_string(mic.value, mic.length); 719 720 packet_send(); 721 } 722 723 buffer_free(&b); 724 gss_release_buffer(&ms, &mic); 725 } 726 } 727 728 return status; 729 } 730 731 /* ARGSUSED */ 732 void 733 input_gssapi_response(int type, u_int32_t plen, void *ctxt) 734 { 735 Authctxt *authctxt = ctxt; 736 Gssctxt *gssctxt; 737 int oidlen; 738 char *oidv; 739 740 if (authctxt == NULL) 741 fatal("input_gssapi_response: no authentication context"); 742 gssctxt = authctxt->methoddata; 743 744 /* Setup our OID */ 745 oidv = packet_get_string(&oidlen); 746 747 if (oidlen <= 2 || 748 oidv[0] != SSH_GSS_OIDTYPE || 749 oidv[1] != oidlen - 2) { 750 xfree(oidv); 751 debug("Badly encoded mechanism OID received"); 752 userauth(authctxt, NULL); 753 return; 754 } 755 756 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 757 fatal("Server returned different OID than expected"); 758 759 packet_check_eom(); 760 761 xfree(oidv); 762 763 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 764 /* Start again with next method on list */ 765 debug("Trying to start again"); 766 userauth(authctxt, NULL); 767 return; 768 } 769 } 770 771 /* ARGSUSED */ 772 void 773 input_gssapi_token(int type, u_int32_t plen, void *ctxt) 774 { 775 Authctxt *authctxt = ctxt; 776 gss_buffer_desc recv_tok; 777 OM_uint32 status; 778 u_int slen; 779 780 if (authctxt == NULL) 781 fatal("input_gssapi_response: no authentication context"); 782 783 recv_tok.value = packet_get_string(&slen); 784 recv_tok.length = slen; /* safe typecast */ 785 786 packet_check_eom(); 787 788 status = process_gssapi_token(ctxt, &recv_tok); 789 790 xfree(recv_tok.value); 791 792 if (GSS_ERROR(status)) { 793 /* Start again with the next method in the list */ 794 userauth(authctxt, NULL); 795 return; 796 } 797 } 798 799 /* ARGSUSED */ 800 void 801 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 802 { 803 Authctxt *authctxt = ctxt; 804 Gssctxt *gssctxt; 805 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 806 gss_buffer_desc recv_tok; 807 OM_uint32 status, ms; 808 u_int len; 809 810 if (authctxt == NULL) 811 fatal("input_gssapi_response: no authentication context"); 812 gssctxt = authctxt->methoddata; 813 814 recv_tok.value = packet_get_string(&len); 815 recv_tok.length = len; 816 817 packet_check_eom(); 818 819 /* Stick it into GSSAPI and see what it says */ 820 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 821 &recv_tok, &send_tok, NULL); 822 823 xfree(recv_tok.value); 824 gss_release_buffer(&ms, &send_tok); 825 826 /* Server will be returning a failed packet after this one */ 827 } 828 829 /* ARGSUSED */ 830 void 831 input_gssapi_error(int type, u_int32_t plen, void *ctxt) 832 { 833 OM_uint32 maj, min; 834 char *msg; 835 char *lang; 836 837 maj=packet_get_int(); 838 min=packet_get_int(); 839 msg=packet_get_string(NULL); 840 lang=packet_get_string(NULL); 841 842 packet_check_eom(); 843 844 debug("Server GSSAPI Error:\n%s", msg); 845 xfree(msg); 846 xfree(lang); 847 } 848 #endif /* GSSAPI */ 849 850 int 851 userauth_none(Authctxt *authctxt) 852 { 853 /* initial userauth request */ 854 packet_start(SSH2_MSG_USERAUTH_REQUEST); 855 packet_put_cstring(authctxt->server_user); 856 packet_put_cstring(authctxt->service); 857 packet_put_cstring(authctxt->method->name); 858 packet_send(); 859 return 1; 860 } 861 862 int 863 userauth_passwd(Authctxt *authctxt) 864 { 865 static int attempt = 0; 866 char prompt[150]; 867 char *password; 868 const char *host = options.host_key_alias ? options.host_key_alias : 869 authctxt->host; 870 871 if (attempt++ >= options.number_of_password_prompts) 872 return 0; 873 874 if (attempt != 1) 875 error("Permission denied, please try again."); 876 877 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 878 authctxt->server_user, host); 879 password = read_passphrase(prompt, 0); 880 packet_start(SSH2_MSG_USERAUTH_REQUEST); 881 packet_put_cstring(authctxt->server_user); 882 packet_put_cstring(authctxt->service); 883 packet_put_cstring(authctxt->method->name); 884 packet_put_char(0); 885 packet_put_cstring(password); 886 memset(password, 0, strlen(password)); 887 xfree(password); 888 packet_add_padding(64); 889 packet_send(); 890 891 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 892 &input_userauth_passwd_changereq); 893 894 return 1; 895 } 896 897 /* 898 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 899 */ 900 /* ARGSUSED */ 901 void 902 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 903 { 904 Authctxt *authctxt = ctxt; 905 char *info, *lang, *password = NULL, *retype = NULL; 906 char prompt[150]; 907 const char *host = options.host_key_alias ? options.host_key_alias : 908 authctxt->host; 909 910 debug2("input_userauth_passwd_changereq"); 911 912 if (authctxt == NULL) 913 fatal("input_userauth_passwd_changereq: " 914 "no authentication context"); 915 916 info = packet_get_string(NULL); 917 lang = packet_get_string(NULL); 918 if (strlen(info) > 0) 919 logit("%s", info); 920 xfree(info); 921 xfree(lang); 922 packet_start(SSH2_MSG_USERAUTH_REQUEST); 923 packet_put_cstring(authctxt->server_user); 924 packet_put_cstring(authctxt->service); 925 packet_put_cstring(authctxt->method->name); 926 packet_put_char(1); /* additional info */ 927 snprintf(prompt, sizeof(prompt), 928 "Enter %.30s@%.128s's old password: ", 929 authctxt->server_user, host); 930 password = read_passphrase(prompt, 0); 931 packet_put_cstring(password); 932 memset(password, 0, strlen(password)); 933 xfree(password); 934 password = NULL; 935 while (password == NULL) { 936 snprintf(prompt, sizeof(prompt), 937 "Enter %.30s@%.128s's new password: ", 938 authctxt->server_user, host); 939 password = read_passphrase(prompt, RP_ALLOW_EOF); 940 if (password == NULL) { 941 /* bail out */ 942 return; 943 } 944 snprintf(prompt, sizeof(prompt), 945 "Retype %.30s@%.128s's new password: ", 946 authctxt->server_user, host); 947 retype = read_passphrase(prompt, 0); 948 if (strcmp(password, retype) != 0) { 949 memset(password, 0, strlen(password)); 950 xfree(password); 951 logit("Mismatch; try again, EOF to quit."); 952 password = NULL; 953 } 954 memset(retype, 0, strlen(retype)); 955 xfree(retype); 956 } 957 packet_put_cstring(password); 958 memset(password, 0, strlen(password)); 959 xfree(password); 960 packet_add_padding(64); 961 packet_send(); 962 963 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 964 &input_userauth_passwd_changereq); 965 } 966 967 #ifdef JPAKE 968 static char * 969 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 970 { 971 /* OpenBSD crypt(3) handles all of these */ 972 if (strcmp(crypt_scheme, "crypt") == 0 || 973 strcmp(crypt_scheme, "bcrypt") == 0 || 974 strcmp(crypt_scheme, "md5crypt") == 0 || 975 strcmp(crypt_scheme, "crypt-extended") == 0) 976 return xstrdup(crypt(password, salt)); 977 error("%s: unsupported password encryption scheme \"%.100s\"", 978 __func__, crypt_scheme); 979 return NULL; 980 } 981 982 static BIGNUM * 983 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 984 const char *salt) 985 { 986 char prompt[256], *password, *crypted; 987 u_char *secret; 988 u_int secret_len; 989 BIGNUM *ret; 990 991 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 992 authctxt->server_user, authctxt->host); 993 password = read_passphrase(prompt, 0); 994 995 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 996 logit("Disabling %s authentication", authctxt->method->name); 997 authctxt->method->enabled = NULL; 998 /* Continue with an empty password to fail gracefully */ 999 crypted = xstrdup(""); 1000 } 1001 1002 #ifdef JPAKE_DEBUG 1003 debug3("%s: salt = %s", __func__, salt); 1004 debug3("%s: scheme = %s", __func__, crypt_scheme); 1005 debug3("%s: crypted = %s", __func__, crypted); 1006 #endif 1007 1008 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 1009 &secret, &secret_len) != 0) 1010 fatal("%s: hash_buffer", __func__); 1011 1012 bzero(password, strlen(password)); 1013 bzero(crypted, strlen(crypted)); 1014 xfree(password); 1015 xfree(crypted); 1016 1017 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 1018 fatal("%s: BN_bin2bn (secret)", __func__); 1019 bzero(secret, secret_len); 1020 xfree(secret); 1021 1022 return ret; 1023 } 1024 1025 /* ARGSUSED */ 1026 void 1027 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 1028 { 1029 Authctxt *authctxt = ctxt; 1030 struct jpake_ctx *pctx = authctxt->methoddata; 1031 u_char *x3_proof, *x4_proof, *x2_s_proof; 1032 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 1033 char *crypt_scheme, *salt; 1034 1035 /* Disable this message */ 1036 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 1037 1038 if ((pctx->g_x3 = BN_new()) == NULL || 1039 (pctx->g_x4 = BN_new()) == NULL) 1040 fatal("%s: BN_new", __func__); 1041 1042 /* Fetch step 1 values */ 1043 crypt_scheme = packet_get_string(NULL); 1044 salt = packet_get_string(NULL); 1045 pctx->server_id = packet_get_string(&pctx->server_id_len); 1046 packet_get_bignum2(pctx->g_x3); 1047 packet_get_bignum2(pctx->g_x4); 1048 x3_proof = packet_get_string(&x3_proof_len); 1049 x4_proof = packet_get_string(&x4_proof_len); 1050 packet_check_eom(); 1051 1052 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1053 1054 /* Obtain password and derive secret */ 1055 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1056 bzero(crypt_scheme, strlen(crypt_scheme)); 1057 bzero(salt, strlen(salt)); 1058 xfree(crypt_scheme); 1059 xfree(salt); 1060 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1061 1062 /* Calculate step 2 values */ 1063 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1064 pctx->g_x3, pctx->g_x4, pctx->x2, 1065 pctx->server_id, pctx->server_id_len, 1066 pctx->client_id, pctx->client_id_len, 1067 x3_proof, x3_proof_len, 1068 x4_proof, x4_proof_len, 1069 &pctx->a, 1070 &x2_s_proof, &x2_s_proof_len); 1071 1072 bzero(x3_proof, x3_proof_len); 1073 bzero(x4_proof, x4_proof_len); 1074 xfree(x3_proof); 1075 xfree(x4_proof); 1076 1077 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1078 1079 /* Send values for step 2 */ 1080 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1081 packet_put_bignum2(pctx->a); 1082 packet_put_string(x2_s_proof, x2_s_proof_len); 1083 packet_send(); 1084 1085 bzero(x2_s_proof, x2_s_proof_len); 1086 xfree(x2_s_proof); 1087 1088 /* Expect step 2 packet from peer */ 1089 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1090 input_userauth_jpake_server_step2); 1091 } 1092 1093 /* ARGSUSED */ 1094 void 1095 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1096 { 1097 Authctxt *authctxt = ctxt; 1098 struct jpake_ctx *pctx = authctxt->methoddata; 1099 u_char *x4_s_proof; 1100 u_int x4_s_proof_len; 1101 1102 /* Disable this message */ 1103 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1104 1105 if ((pctx->b = BN_new()) == NULL) 1106 fatal("%s: BN_new", __func__); 1107 1108 /* Fetch step 2 values */ 1109 packet_get_bignum2(pctx->b); 1110 x4_s_proof = packet_get_string(&x4_s_proof_len); 1111 packet_check_eom(); 1112 1113 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1114 1115 /* Derive shared key and calculate confirmation hash */ 1116 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1117 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1118 pctx->client_id, pctx->client_id_len, 1119 pctx->server_id, pctx->server_id_len, 1120 session_id2, session_id2_len, 1121 x4_s_proof, x4_s_proof_len, 1122 &pctx->k, 1123 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1124 1125 bzero(x4_s_proof, x4_s_proof_len); 1126 xfree(x4_s_proof); 1127 1128 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1129 1130 /* Send key confirmation proof */ 1131 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1132 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1133 packet_send(); 1134 1135 /* Expect confirmation from peer */ 1136 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1137 input_userauth_jpake_server_confirm); 1138 } 1139 1140 /* ARGSUSED */ 1141 void 1142 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1143 { 1144 Authctxt *authctxt = ctxt; 1145 struct jpake_ctx *pctx = authctxt->methoddata; 1146 1147 /* Disable this message */ 1148 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1149 1150 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1151 packet_check_eom(); 1152 1153 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1154 1155 /* Verify expected confirmation hash */ 1156 if (jpake_check_confirm(pctx->k, 1157 pctx->server_id, pctx->server_id_len, 1158 session_id2, session_id2_len, 1159 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1160 debug("%s: %s success", __func__, authctxt->method->name); 1161 else { 1162 debug("%s: confirmation mismatch", __func__); 1163 /* XXX stash this so if auth succeeds then we can warn/kill */ 1164 } 1165 1166 userauth_jpake_cleanup(authctxt); 1167 } 1168 #endif /* JPAKE */ 1169 1170 static int 1171 identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1172 u_char *data, u_int datalen) 1173 { 1174 Key *prv; 1175 int ret; 1176 1177 /* the agent supports this key */ 1178 if (id->ac) 1179 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1180 data, datalen)); 1181 /* 1182 * we have already loaded the private key or 1183 * the private key is stored in external hardware 1184 */ 1185 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1186 return (key_sign(id->key, sigp, lenp, data, datalen)); 1187 /* load the private key from the file */ 1188 if ((prv = load_identity_file(id->filename, id->userprovided)) == NULL) 1189 return (-1); 1190 ret = key_sign(prv, sigp, lenp, data, datalen); 1191 key_free(prv); 1192 return (ret); 1193 } 1194 1195 static int 1196 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1197 { 1198 Buffer b; 1199 u_char *blob, *signature; 1200 u_int bloblen, slen; 1201 u_int skip = 0; 1202 int ret = -1; 1203 int have_sig = 1; 1204 char *fp; 1205 1206 fp = key_fingerprint(id->key, SSH_FP_MD5, SSH_FP_HEX); 1207 debug3("sign_and_send_pubkey: %s %s", key_type(id->key), fp); 1208 xfree(fp); 1209 1210 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1211 /* we cannot handle this key */ 1212 debug3("sign_and_send_pubkey: cannot handle key"); 1213 return 0; 1214 } 1215 /* data to be signed */ 1216 buffer_init(&b); 1217 if (datafellows & SSH_OLD_SESSIONID) { 1218 buffer_append(&b, session_id2, session_id2_len); 1219 skip = session_id2_len; 1220 } else { 1221 buffer_put_string(&b, session_id2, session_id2_len); 1222 skip = buffer_len(&b); 1223 } 1224 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1225 buffer_put_cstring(&b, authctxt->server_user); 1226 buffer_put_cstring(&b, 1227 datafellows & SSH_BUG_PKSERVICE ? 1228 "ssh-userauth" : 1229 authctxt->service); 1230 if (datafellows & SSH_BUG_PKAUTH) { 1231 buffer_put_char(&b, have_sig); 1232 } else { 1233 buffer_put_cstring(&b, authctxt->method->name); 1234 buffer_put_char(&b, have_sig); 1235 buffer_put_cstring(&b, key_ssh_name(id->key)); 1236 } 1237 buffer_put_string(&b, blob, bloblen); 1238 1239 /* generate signature */ 1240 ret = identity_sign(id, &signature, &slen, 1241 buffer_ptr(&b), buffer_len(&b)); 1242 if (ret == -1) { 1243 xfree(blob); 1244 buffer_free(&b); 1245 return 0; 1246 } 1247 #ifdef DEBUG_PK 1248 buffer_dump(&b); 1249 #endif 1250 if (datafellows & SSH_BUG_PKSERVICE) { 1251 buffer_clear(&b); 1252 buffer_append(&b, session_id2, session_id2_len); 1253 skip = session_id2_len; 1254 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1255 buffer_put_cstring(&b, authctxt->server_user); 1256 buffer_put_cstring(&b, authctxt->service); 1257 buffer_put_cstring(&b, authctxt->method->name); 1258 buffer_put_char(&b, have_sig); 1259 if (!(datafellows & SSH_BUG_PKAUTH)) 1260 buffer_put_cstring(&b, key_ssh_name(id->key)); 1261 buffer_put_string(&b, blob, bloblen); 1262 } 1263 xfree(blob); 1264 1265 /* append signature */ 1266 buffer_put_string(&b, signature, slen); 1267 xfree(signature); 1268 1269 /* skip session id and packet type */ 1270 if (buffer_len(&b) < skip + 1) 1271 fatal("userauth_pubkey: internal error"); 1272 buffer_consume(&b, skip + 1); 1273 1274 /* put remaining data from buffer into packet */ 1275 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1276 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1277 buffer_free(&b); 1278 packet_send(); 1279 1280 return 1; 1281 } 1282 1283 static int 1284 send_pubkey_test(Authctxt *authctxt, Identity *id) 1285 { 1286 u_char *blob; 1287 u_int bloblen, have_sig = 0; 1288 1289 debug3("send_pubkey_test"); 1290 1291 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1292 /* we cannot handle this key */ 1293 debug3("send_pubkey_test: cannot handle key"); 1294 return 0; 1295 } 1296 /* register callback for USERAUTH_PK_OK message */ 1297 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1298 1299 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1300 packet_put_cstring(authctxt->server_user); 1301 packet_put_cstring(authctxt->service); 1302 packet_put_cstring(authctxt->method->name); 1303 packet_put_char(have_sig); 1304 if (!(datafellows & SSH_BUG_PKAUTH)) 1305 packet_put_cstring(key_ssh_name(id->key)); 1306 packet_put_string(blob, bloblen); 1307 xfree(blob); 1308 packet_send(); 1309 return 1; 1310 } 1311 1312 static Key * 1313 load_identity_file(char *filename, int userprovided) 1314 { 1315 Key *private; 1316 char prompt[300], *passphrase; 1317 int perm_ok = 0, quit, i; 1318 struct stat st; 1319 1320 if (stat(filename, &st) < 0) { 1321 (userprovided ? logit : debug3)("no such identity: %s: %s", 1322 filename, strerror(errno)); 1323 return NULL; 1324 } 1325 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1326 if (!perm_ok) 1327 return NULL; 1328 if (private == NULL) { 1329 if (options.batch_mode) 1330 return NULL; 1331 snprintf(prompt, sizeof prompt, 1332 "Enter passphrase for key '%.100s': ", filename); 1333 for (i = 0; i < options.number_of_password_prompts; i++) { 1334 passphrase = read_passphrase(prompt, 0); 1335 if (strcmp(passphrase, "") != 0) { 1336 private = key_load_private_type(KEY_UNSPEC, 1337 filename, passphrase, NULL, NULL); 1338 quit = 0; 1339 } else { 1340 debug2("no passphrase given, try next key"); 1341 quit = 1; 1342 } 1343 memset(passphrase, 0, strlen(passphrase)); 1344 xfree(passphrase); 1345 if (private != NULL || quit) 1346 break; 1347 debug2("bad passphrase given, try again..."); 1348 } 1349 } 1350 return private; 1351 } 1352 1353 /* 1354 * try keys in the following order: 1355 * 1. agent keys that are found in the config file 1356 * 2. other agent keys 1357 * 3. keys that are only listed in the config file 1358 */ 1359 static void 1360 pubkey_prepare(Authctxt *authctxt) 1361 { 1362 Identity *id, *id2, *tmp; 1363 Idlist agent, files, *preferred; 1364 Key *key; 1365 AuthenticationConnection *ac; 1366 char *comment; 1367 int i, found; 1368 1369 TAILQ_INIT(&agent); /* keys from the agent */ 1370 TAILQ_INIT(&files); /* keys from the config file */ 1371 preferred = &authctxt->keys; 1372 TAILQ_INIT(preferred); /* preferred order of keys */ 1373 1374 /* list of keys stored in the filesystem and PKCS#11 */ 1375 for (i = 0; i < options.num_identity_files; i++) { 1376 key = options.identity_keys[i]; 1377 if (key && key->type == KEY_RSA1) 1378 continue; 1379 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1380 continue; 1381 options.identity_keys[i] = NULL; 1382 id = xcalloc(1, sizeof(*id)); 1383 id->key = key; 1384 id->filename = xstrdup(options.identity_files[i]); 1385 id->userprovided = options.identity_file_userprovided[i]; 1386 TAILQ_INSERT_TAIL(&files, id, next); 1387 } 1388 /* Prefer PKCS11 keys that are explicitly listed */ 1389 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1390 if (id->key == NULL || (id->key->flags & KEY_FLAG_EXT) == 0) 1391 continue; 1392 found = 0; 1393 TAILQ_FOREACH(id2, &files, next) { 1394 if (id2->key == NULL || 1395 (id2->key->flags & KEY_FLAG_EXT) != 0) 1396 continue; 1397 if (key_equal(id->key, id2->key)) { 1398 TAILQ_REMOVE(&files, id, next); 1399 TAILQ_INSERT_TAIL(preferred, id, next); 1400 found = 1; 1401 break; 1402 } 1403 } 1404 /* If IdentitiesOnly set and key not found then don't use it */ 1405 if (!found && options.identities_only) { 1406 TAILQ_REMOVE(&files, id, next); 1407 bzero(id, sizeof(id)); 1408 free(id); 1409 } 1410 } 1411 /* list of keys supported by the agent */ 1412 if ((ac = ssh_get_authentication_connection())) { 1413 for (key = ssh_get_first_identity(ac, &comment, 2); 1414 key != NULL; 1415 key = ssh_get_next_identity(ac, &comment, 2)) { 1416 found = 0; 1417 TAILQ_FOREACH(id, &files, next) { 1418 /* agent keys from the config file are preferred */ 1419 if (key_equal(key, id->key)) { 1420 key_free(key); 1421 xfree(comment); 1422 TAILQ_REMOVE(&files, id, next); 1423 TAILQ_INSERT_TAIL(preferred, id, next); 1424 id->ac = ac; 1425 found = 1; 1426 break; 1427 } 1428 } 1429 if (!found && !options.identities_only) { 1430 id = xcalloc(1, sizeof(*id)); 1431 id->key = key; 1432 id->filename = comment; 1433 id->ac = ac; 1434 TAILQ_INSERT_TAIL(&agent, id, next); 1435 } 1436 } 1437 /* append remaining agent keys */ 1438 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1439 TAILQ_REMOVE(&agent, id, next); 1440 TAILQ_INSERT_TAIL(preferred, id, next); 1441 } 1442 authctxt->agent = ac; 1443 } 1444 /* append remaining keys from the config file */ 1445 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1446 TAILQ_REMOVE(&files, id, next); 1447 TAILQ_INSERT_TAIL(preferred, id, next); 1448 } 1449 TAILQ_FOREACH(id, preferred, next) { 1450 debug2("key: %s (%p),%s", id->filename, id->key, 1451 id->userprovided ? " explicit" : ""); 1452 } 1453 } 1454 1455 static void 1456 pubkey_cleanup(Authctxt *authctxt) 1457 { 1458 Identity *id; 1459 1460 if (authctxt->agent != NULL) 1461 ssh_close_authentication_connection(authctxt->agent); 1462 for (id = TAILQ_FIRST(&authctxt->keys); id; 1463 id = TAILQ_FIRST(&authctxt->keys)) { 1464 TAILQ_REMOVE(&authctxt->keys, id, next); 1465 if (id->key) 1466 key_free(id->key); 1467 if (id->filename) 1468 xfree(id->filename); 1469 xfree(id); 1470 } 1471 } 1472 1473 int 1474 userauth_pubkey(Authctxt *authctxt) 1475 { 1476 Identity *id; 1477 int sent = 0; 1478 1479 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1480 if (id->tried++) 1481 return (0); 1482 /* move key to the end of the queue */ 1483 TAILQ_REMOVE(&authctxt->keys, id, next); 1484 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1485 /* 1486 * send a test message if we have the public key. for 1487 * encrypted keys we cannot do this and have to load the 1488 * private key instead 1489 */ 1490 if (id->key && id->key->type != KEY_RSA1) { 1491 debug("Offering %s public key: %s", key_type(id->key), 1492 id->filename); 1493 sent = send_pubkey_test(authctxt, id); 1494 } else if (id->key == NULL) { 1495 debug("Trying private key: %s", id->filename); 1496 id->key = load_identity_file(id->filename, 1497 id->userprovided); 1498 if (id->key != NULL) { 1499 id->isprivate = 1; 1500 sent = sign_and_send_pubkey(authctxt, id); 1501 key_free(id->key); 1502 id->key = NULL; 1503 } 1504 } 1505 if (sent) 1506 return (sent); 1507 } 1508 return (0); 1509 } 1510 1511 /* 1512 * Send userauth request message specifying keyboard-interactive method. 1513 */ 1514 int 1515 userauth_kbdint(Authctxt *authctxt) 1516 { 1517 static int attempt = 0; 1518 1519 if (attempt++ >= options.number_of_password_prompts) 1520 return 0; 1521 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1522 if (attempt > 1 && !authctxt->info_req_seen) { 1523 debug3("userauth_kbdint: disable: no info_req_seen"); 1524 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1525 return 0; 1526 } 1527 1528 debug2("userauth_kbdint"); 1529 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1530 packet_put_cstring(authctxt->server_user); 1531 packet_put_cstring(authctxt->service); 1532 packet_put_cstring(authctxt->method->name); 1533 packet_put_cstring(""); /* lang */ 1534 packet_put_cstring(options.kbd_interactive_devices ? 1535 options.kbd_interactive_devices : ""); 1536 packet_send(); 1537 1538 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1539 return 1; 1540 } 1541 1542 /* 1543 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1544 */ 1545 void 1546 input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1547 { 1548 Authctxt *authctxt = ctxt; 1549 char *name, *inst, *lang, *prompt, *response; 1550 u_int num_prompts, i; 1551 int echo = 0; 1552 1553 debug2("input_userauth_info_req"); 1554 1555 if (authctxt == NULL) 1556 fatal("input_userauth_info_req: no authentication context"); 1557 1558 authctxt->info_req_seen = 1; 1559 1560 name = packet_get_string(NULL); 1561 inst = packet_get_string(NULL); 1562 lang = packet_get_string(NULL); 1563 if (strlen(name) > 0) 1564 logit("%s", name); 1565 if (strlen(inst) > 0) 1566 logit("%s", inst); 1567 xfree(name); 1568 xfree(inst); 1569 xfree(lang); 1570 1571 num_prompts = packet_get_int(); 1572 /* 1573 * Begin to build info response packet based on prompts requested. 1574 * We commit to providing the correct number of responses, so if 1575 * further on we run into a problem that prevents this, we have to 1576 * be sure and clean this up and send a correct error response. 1577 */ 1578 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1579 packet_put_int(num_prompts); 1580 1581 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1582 for (i = 0; i < num_prompts; i++) { 1583 prompt = packet_get_string(NULL); 1584 echo = packet_get_char(); 1585 1586 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1587 1588 packet_put_cstring(response); 1589 memset(response, 0, strlen(response)); 1590 xfree(response); 1591 xfree(prompt); 1592 } 1593 packet_check_eom(); /* done with parsing incoming message. */ 1594 1595 packet_add_padding(64); 1596 packet_send(); 1597 } 1598 1599 static int 1600 ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1601 u_char *data, u_int datalen) 1602 { 1603 Buffer b; 1604 struct stat st; 1605 pid_t pid; 1606 int to[2], from[2], status, version = 2; 1607 1608 debug2("ssh_keysign called"); 1609 1610 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1611 error("ssh_keysign: not installed: %s", strerror(errno)); 1612 return -1; 1613 } 1614 if (fflush(stdout) != 0) 1615 error("ssh_keysign: fflush: %s", strerror(errno)); 1616 if (pipe(to) < 0) { 1617 error("ssh_keysign: pipe: %s", strerror(errno)); 1618 return -1; 1619 } 1620 if (pipe(from) < 0) { 1621 error("ssh_keysign: pipe: %s", strerror(errno)); 1622 return -1; 1623 } 1624 if ((pid = fork()) < 0) { 1625 error("ssh_keysign: fork: %s", strerror(errno)); 1626 return -1; 1627 } 1628 if (pid == 0) { 1629 /* keep the socket on exec */ 1630 fcntl(packet_get_connection_in(), F_SETFD, 0); 1631 permanently_drop_suid(getuid()); 1632 close(from[0]); 1633 if (dup2(from[1], STDOUT_FILENO) < 0) 1634 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1635 close(to[1]); 1636 if (dup2(to[0], STDIN_FILENO) < 0) 1637 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1638 close(from[1]); 1639 close(to[0]); 1640 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1641 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1642 strerror(errno)); 1643 } 1644 close(from[1]); 1645 close(to[0]); 1646 1647 buffer_init(&b); 1648 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1649 buffer_put_string(&b, data, datalen); 1650 if (ssh_msg_send(to[1], version, &b) == -1) 1651 fatal("ssh_keysign: couldn't send request"); 1652 1653 if (ssh_msg_recv(from[0], &b) < 0) { 1654 error("ssh_keysign: no reply"); 1655 buffer_free(&b); 1656 return -1; 1657 } 1658 close(from[0]); 1659 close(to[1]); 1660 1661 while (waitpid(pid, &status, 0) < 0) 1662 if (errno != EINTR) 1663 break; 1664 1665 if (buffer_get_char(&b) != version) { 1666 error("ssh_keysign: bad version"); 1667 buffer_free(&b); 1668 return -1; 1669 } 1670 *sigp = buffer_get_string(&b, lenp); 1671 buffer_free(&b); 1672 1673 return 0; 1674 } 1675 1676 int 1677 userauth_hostbased(Authctxt *authctxt) 1678 { 1679 Key *private = NULL; 1680 Sensitive *sensitive = authctxt->sensitive; 1681 Buffer b; 1682 u_char *signature, *blob; 1683 char *chost, *pkalg, *p; 1684 const char *service; 1685 u_int blen, slen; 1686 int ok, i, found = 0; 1687 1688 /* check for a useful key */ 1689 for (i = 0; i < sensitive->nkeys; i++) { 1690 private = sensitive->keys[i]; 1691 if (private && private->type != KEY_RSA1) { 1692 found = 1; 1693 /* we take and free the key */ 1694 sensitive->keys[i] = NULL; 1695 break; 1696 } 1697 } 1698 if (!found) { 1699 debug("No more client hostkeys for hostbased authentication."); 1700 return 0; 1701 } 1702 if (key_to_blob(private, &blob, &blen) == 0) { 1703 key_free(private); 1704 return 0; 1705 } 1706 /* figure out a name for the client host */ 1707 p = get_local_name(packet_get_connection_in()); 1708 if (p == NULL) { 1709 error("userauth_hostbased: cannot get local ipaddr/name"); 1710 key_free(private); 1711 xfree(blob); 1712 return 0; 1713 } 1714 xasprintf(&chost, "%s.", p); 1715 debug2("userauth_hostbased: chost %s", chost); 1716 xfree(p); 1717 1718 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1719 authctxt->service; 1720 pkalg = xstrdup(key_ssh_name(private)); 1721 buffer_init(&b); 1722 /* construct data */ 1723 buffer_put_string(&b, session_id2, session_id2_len); 1724 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1725 buffer_put_cstring(&b, authctxt->server_user); 1726 buffer_put_cstring(&b, service); 1727 buffer_put_cstring(&b, authctxt->method->name); 1728 buffer_put_cstring(&b, pkalg); 1729 buffer_put_string(&b, blob, blen); 1730 buffer_put_cstring(&b, chost); 1731 buffer_put_cstring(&b, authctxt->local_user); 1732 #ifdef DEBUG_PK 1733 buffer_dump(&b); 1734 #endif 1735 if (sensitive->external_keysign) 1736 ok = ssh_keysign(private, &signature, &slen, 1737 buffer_ptr(&b), buffer_len(&b)); 1738 else 1739 ok = key_sign(private, &signature, &slen, 1740 buffer_ptr(&b), buffer_len(&b)); 1741 key_free(private); 1742 buffer_free(&b); 1743 if (ok != 0) { 1744 error("key_sign failed"); 1745 xfree(chost); 1746 xfree(pkalg); 1747 xfree(blob); 1748 return 0; 1749 } 1750 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1751 packet_put_cstring(authctxt->server_user); 1752 packet_put_cstring(authctxt->service); 1753 packet_put_cstring(authctxt->method->name); 1754 packet_put_cstring(pkalg); 1755 packet_put_string(blob, blen); 1756 packet_put_cstring(chost); 1757 packet_put_cstring(authctxt->local_user); 1758 packet_put_string(signature, slen); 1759 memset(signature, 's', slen); 1760 xfree(signature); 1761 xfree(chost); 1762 xfree(pkalg); 1763 xfree(blob); 1764 1765 packet_send(); 1766 return 1; 1767 } 1768 1769 #ifdef JPAKE 1770 int 1771 userauth_jpake(Authctxt *authctxt) 1772 { 1773 struct jpake_ctx *pctx; 1774 u_char *x1_proof, *x2_proof; 1775 u_int x1_proof_len, x2_proof_len; 1776 static int attempt = 0; /* XXX share with userauth_password's? */ 1777 1778 if (attempt++ >= options.number_of_password_prompts) 1779 return 0; 1780 if (attempt != 1) 1781 error("Permission denied, please try again."); 1782 1783 if (authctxt->methoddata != NULL) 1784 fatal("%s: authctxt->methoddata already set (%p)", 1785 __func__, authctxt->methoddata); 1786 1787 authctxt->methoddata = pctx = jpake_new(); 1788 1789 /* 1790 * Send request immediately, to get the protocol going while 1791 * we do the initial computations. 1792 */ 1793 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1794 packet_put_cstring(authctxt->server_user); 1795 packet_put_cstring(authctxt->service); 1796 packet_put_cstring(authctxt->method->name); 1797 packet_send(); 1798 packet_write_wait(); 1799 1800 jpake_step1(pctx->grp, 1801 &pctx->client_id, &pctx->client_id_len, 1802 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1803 &x1_proof, &x1_proof_len, 1804 &x2_proof, &x2_proof_len); 1805 1806 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1807 1808 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1809 packet_put_string(pctx->client_id, pctx->client_id_len); 1810 packet_put_bignum2(pctx->g_x1); 1811 packet_put_bignum2(pctx->g_x2); 1812 packet_put_string(x1_proof, x1_proof_len); 1813 packet_put_string(x2_proof, x2_proof_len); 1814 packet_send(); 1815 1816 bzero(x1_proof, x1_proof_len); 1817 bzero(x2_proof, x2_proof_len); 1818 xfree(x1_proof); 1819 xfree(x2_proof); 1820 1821 /* Expect step 1 packet from peer */ 1822 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1823 input_userauth_jpake_server_step1); 1824 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, 1825 &input_userauth_success_unexpected); 1826 1827 return 1; 1828 } 1829 1830 void 1831 userauth_jpake_cleanup(Authctxt *authctxt) 1832 { 1833 debug3("%s: clean up", __func__); 1834 if (authctxt->methoddata != NULL) { 1835 jpake_free(authctxt->methoddata); 1836 authctxt->methoddata = NULL; 1837 } 1838 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 1839 } 1840 #endif /* JPAKE */ 1841 1842 /* find auth method */ 1843 1844 /* 1845 * given auth method name, if configurable options permit this method fill 1846 * in auth_ident field and return true, otherwise return false. 1847 */ 1848 static int 1849 authmethod_is_enabled(Authmethod *method) 1850 { 1851 if (method == NULL) 1852 return 0; 1853 /* return false if options indicate this method is disabled */ 1854 if (method->enabled == NULL || *method->enabled == 0) 1855 return 0; 1856 /* return false if batch mode is enabled but method needs interactive mode */ 1857 if (method->batch_flag != NULL && *method->batch_flag != 0) 1858 return 0; 1859 return 1; 1860 } 1861 1862 static Authmethod * 1863 authmethod_lookup(const char *name) 1864 { 1865 Authmethod *method = NULL; 1866 if (name != NULL) 1867 for (method = authmethods; method->name != NULL; method++) 1868 if (strcmp(name, method->name) == 0) 1869 return method; 1870 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1871 return NULL; 1872 } 1873 1874 /* XXX internal state */ 1875 static Authmethod *current = NULL; 1876 static char *supported = NULL; 1877 static char *preferred = NULL; 1878 1879 /* 1880 * Given the authentication method list sent by the server, return the 1881 * next method we should try. If the server initially sends a nil list, 1882 * use a built-in default list. 1883 */ 1884 static Authmethod * 1885 authmethod_get(char *authlist) 1886 { 1887 char *name = NULL; 1888 u_int next; 1889 1890 /* Use a suitable default if we're passed a nil list. */ 1891 if (authlist == NULL || strlen(authlist) == 0) 1892 authlist = options.preferred_authentications; 1893 1894 if (supported == NULL || strcmp(authlist, supported) != 0) { 1895 debug3("start over, passed a different list %s", authlist); 1896 if (supported != NULL) 1897 xfree(supported); 1898 supported = xstrdup(authlist); 1899 preferred = options.preferred_authentications; 1900 debug3("preferred %s", preferred); 1901 current = NULL; 1902 } else if (current != NULL && authmethod_is_enabled(current)) 1903 return current; 1904 1905 for (;;) { 1906 if ((name = match_list(preferred, supported, &next)) == NULL) { 1907 debug("No more authentication methods to try."); 1908 current = NULL; 1909 return NULL; 1910 } 1911 preferred += next; 1912 debug3("authmethod_lookup %s", name); 1913 debug3("remaining preferred: %s", preferred); 1914 if ((current = authmethod_lookup(name)) != NULL && 1915 authmethod_is_enabled(current)) { 1916 debug3("authmethod_is_enabled %s", name); 1917 debug("Next authentication method: %s", name); 1918 xfree(name); 1919 return current; 1920 } 1921 } 1922 } 1923 1924 static char * 1925 authmethods_get(void) 1926 { 1927 Authmethod *method = NULL; 1928 Buffer b; 1929 char *list; 1930 1931 buffer_init(&b); 1932 for (method = authmethods; method->name != NULL; method++) { 1933 if (authmethod_is_enabled(method)) { 1934 if (buffer_len(&b) > 0) 1935 buffer_append(&b, ",", 1); 1936 buffer_append(&b, method->name, strlen(method->name)); 1937 } 1938 } 1939 buffer_append(&b, "\0", 1); 1940 list = xstrdup(buffer_ptr(&b)); 1941 buffer_free(&b); 1942 return list; 1943 } 1944 1945