1 /* $NetBSD: sshconnect2.c,v 1.4 2009/12/27 01:40:47 christos Exp $ */ 2 /* $OpenBSD: sshconnect2.c,v 1.171 2009/03/05 07:18:19 djm Exp $ */ 3 /* 4 * Copyright (c) 2000 Markus Friedl. All rights reserved. 5 * Copyright (c) 2008 Damien Miller. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 __RCSID("$NetBSD: sshconnect2.c,v 1.4 2009/12/27 01:40:47 christos Exp $"); 30 #include <sys/types.h> 31 #include <sys/socket.h> 32 #include <sys/wait.h> 33 #include <sys/queue.h> 34 #include <sys/stat.h> 35 36 #include <errno.h> 37 #include <netdb.h> 38 #include <stdio.h> 39 #include <string.h> 40 #include <signal.h> 41 #include <pwd.h> 42 #include <unistd.h> 43 #include <vis.h> 44 45 #ifdef KRB5 46 #include <krb5.h> 47 #endif 48 49 #include "xmalloc.h" 50 #include "ssh.h" 51 #include "ssh2.h" 52 #include "buffer.h" 53 #include "packet.h" 54 #include "compat.h" 55 #include "cipher.h" 56 #include "key.h" 57 #include "kex.h" 58 #include "myproposal.h" 59 #include "sshconnect.h" 60 #include "authfile.h" 61 #include "dh.h" 62 #include "authfd.h" 63 #include "log.h" 64 #include "readconf.h" 65 #include "misc.h" 66 #include "match.h" 67 #include "dispatch.h" 68 #include "canohost.h" 69 #include "msg.h" 70 #include "pathnames.h" 71 #include "uidswap.h" 72 #include "schnorr.h" 73 #include "jpake.h" 74 75 #ifdef GSSAPI 76 #include "ssh-gss.h" 77 #endif 78 79 /* import */ 80 extern char *client_version_string; 81 extern char *server_version_string; 82 extern Options options; 83 extern Kex *xxx_kex; 84 85 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */ 86 /* if it is set then prevent the switch to the null cipher */ 87 88 extern int tty_flag; 89 90 /* 91 * SSH2 key exchange 92 */ 93 94 u_char *session_id2 = NULL; 95 u_int session_id2_len = 0; 96 97 char *xxx_host; 98 struct sockaddr *xxx_hostaddr; 99 100 Kex *xxx_kex = NULL; 101 102 static int 103 verify_host_key_callback(Key *hostkey) 104 { 105 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 106 fatal("Host key verification failed."); 107 return 0; 108 } 109 110 void 111 ssh_kex2(char *host, struct sockaddr *hostaddr) 112 { 113 Kex *kex; 114 115 xxx_host = host; 116 xxx_hostaddr = hostaddr; 117 118 if (options.ciphers == (char *)-1) { 119 logit("No valid ciphers for protocol version 2 given, using defaults."); 120 options.ciphers = NULL; 121 } 122 if (options.ciphers != NULL) { 123 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 124 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 125 } 126 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 127 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 128 myproposal[PROPOSAL_ENC_ALGS_STOC] = 129 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 130 if (options.compression) { 131 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 132 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 133 } else { 134 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 135 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 136 } 137 if (options.macs != NULL) { 138 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 139 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 140 } 141 if (options.hostkeyalgorithms != NULL) 142 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 143 options.hostkeyalgorithms; 144 145 if (options.rekey_limit) 146 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 147 148 /* start key exchange */ 149 kex = kex_setup(myproposal); 150 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 151 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 152 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 153 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 154 kex->client_version_string=client_version_string; 155 kex->server_version_string=server_version_string; 156 kex->verify_host_key=&verify_host_key_callback; 157 158 xxx_kex = kex; 159 160 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 161 162 session_id2 = kex->session_id; 163 session_id2_len = kex->session_id_len; 164 165 #ifdef DEBUG_KEXDH 166 /* send 1st encrypted/maced/compressed message */ 167 packet_start(SSH2_MSG_IGNORE); 168 packet_put_cstring("markus"); 169 packet_send(); 170 packet_write_wait(); 171 #endif 172 } 173 174 /* 175 * Authenticate user 176 */ 177 178 typedef struct Authctxt Authctxt; 179 typedef struct Authmethod Authmethod; 180 typedef struct identity Identity; 181 typedef struct idlist Idlist; 182 183 struct identity { 184 TAILQ_ENTRY(identity) next; 185 AuthenticationConnection *ac; /* set if agent supports key */ 186 Key *key; /* public/private key */ 187 char *filename; /* comment for agent-only keys */ 188 int tried; 189 int isprivate; /* key points to the private key */ 190 }; 191 TAILQ_HEAD(idlist, identity); 192 193 struct Authctxt { 194 const char *server_user; 195 const char *local_user; 196 const char *host; 197 const char *service; 198 Authmethod *method; 199 sig_atomic_t success; 200 char *authlist; 201 /* pubkey */ 202 Idlist keys; 203 AuthenticationConnection *agent; 204 /* hostbased */ 205 Sensitive *sensitive; 206 /* kbd-interactive */ 207 int info_req_seen; 208 /* generic */ 209 void *methoddata; 210 }; 211 struct Authmethod { 212 char *name; /* string to compare against server's list */ 213 int (*userauth)(Authctxt *authctxt); 214 void (*cleanup)(Authctxt *authctxt); 215 int *enabled; /* flag in option struct that enables method */ 216 int *batch_flag; /* flag in option struct that disables method */ 217 }; 218 219 void input_userauth_success(int, u_int32_t, void *); 220 void input_userauth_failure(int, u_int32_t, void *); 221 void input_userauth_banner(int, u_int32_t, void *); 222 void input_userauth_error(int, u_int32_t, void *); 223 void input_userauth_info_req(int, u_int32_t, void *); 224 void input_userauth_pk_ok(int, u_int32_t, void *); 225 void input_userauth_passwd_changereq(int, u_int32_t, void *); 226 void input_userauth_jpake_server_step1(int, u_int32_t, void *); 227 void input_userauth_jpake_server_step2(int, u_int32_t, void *); 228 void input_userauth_jpake_server_confirm(int, u_int32_t, void *); 229 230 int userauth_none(Authctxt *); 231 int userauth_pubkey(Authctxt *); 232 int userauth_passwd(Authctxt *); 233 int userauth_kbdint(Authctxt *); 234 int userauth_hostbased(Authctxt *); 235 int userauth_kerberos(Authctxt *); 236 int userauth_jpake(Authctxt *); 237 238 void userauth_jpake_cleanup(Authctxt *); 239 240 #ifdef GSSAPI 241 int userauth_gssapi(Authctxt *authctxt); 242 void input_gssapi_response(int type, u_int32_t, void *); 243 void input_gssapi_token(int type, u_int32_t, void *); 244 void input_gssapi_hash(int type, u_int32_t, void *); 245 void input_gssapi_error(int, u_int32_t, void *); 246 void input_gssapi_errtok(int, u_int32_t, void *); 247 #endif 248 249 void userauth(Authctxt *, char *); 250 251 static int sign_and_send_pubkey(Authctxt *, Identity *); 252 static void pubkey_prepare(Authctxt *); 253 static void pubkey_cleanup(Authctxt *); 254 static Key *load_identity_file(char *); 255 256 static Authmethod *authmethod_get(char *authlist); 257 static Authmethod *authmethod_lookup(const char *name); 258 static char *authmethods_get(void); 259 260 Authmethod authmethods[] = { 261 #ifdef GSSAPI 262 {"gssapi-with-mic", 263 userauth_gssapi, 264 NULL, 265 &options.gss_authentication, 266 NULL}, 267 #endif 268 {"hostbased", 269 userauth_hostbased, 270 NULL, 271 &options.hostbased_authentication, 272 NULL}, 273 #if KRB5 274 {"kerberos-2@ssh.com", 275 userauth_kerberos, 276 NULL, 277 &options.kerberos_authentication, 278 NULL}, 279 #endif 280 {"publickey", 281 userauth_pubkey, 282 NULL, 283 &options.pubkey_authentication, 284 NULL}, 285 #ifdef JPAKE 286 {"jpake-01@openssh.com", 287 userauth_jpake, 288 userauth_jpake_cleanup, 289 &options.zero_knowledge_password_authentication, 290 &options.batch_mode}, 291 #endif 292 {"keyboard-interactive", 293 userauth_kbdint, 294 NULL, 295 &options.kbd_interactive_authentication, 296 &options.batch_mode}, 297 {"password", 298 userauth_passwd, 299 NULL, 300 &options.password_authentication, 301 &options.batch_mode}, 302 {"none", 303 userauth_none, 304 NULL, 305 NULL, 306 NULL}, 307 {NULL, NULL, NULL, NULL, NULL} 308 }; 309 310 void 311 ssh_userauth2(const char *local_user, const char *server_user, char *host, 312 Sensitive *sensitive) 313 { 314 Authctxt authctxt; 315 int type; 316 317 if (options.challenge_response_authentication) 318 options.kbd_interactive_authentication = 1; 319 320 packet_start(SSH2_MSG_SERVICE_REQUEST); 321 packet_put_cstring("ssh-userauth"); 322 packet_send(); 323 debug("SSH2_MSG_SERVICE_REQUEST sent"); 324 packet_write_wait(); 325 type = packet_read(); 326 if (type != SSH2_MSG_SERVICE_ACCEPT) 327 fatal("Server denied authentication request: %d", type); 328 if (packet_remaining() > 0) { 329 char *reply = packet_get_string(NULL); 330 debug2("service_accept: %s", reply); 331 xfree(reply); 332 } else { 333 debug2("buggy server: service_accept w/o service"); 334 } 335 packet_check_eom(); 336 debug("SSH2_MSG_SERVICE_ACCEPT received"); 337 338 if (options.preferred_authentications == NULL) 339 options.preferred_authentications = authmethods_get(); 340 341 /* setup authentication context */ 342 memset(&authctxt, 0, sizeof(authctxt)); 343 pubkey_prepare(&authctxt); 344 authctxt.server_user = server_user; 345 authctxt.local_user = local_user; 346 authctxt.host = host; 347 authctxt.service = "ssh-connection"; /* service name */ 348 authctxt.success = 0; 349 authctxt.method = authmethod_lookup("none"); 350 authctxt.authlist = NULL; 351 authctxt.methoddata = NULL; 352 authctxt.sensitive = sensitive; 353 authctxt.info_req_seen = 0; 354 if (authctxt.method == NULL) 355 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 356 357 /* initial userauth request */ 358 userauth_none(&authctxt); 359 360 dispatch_init(&input_userauth_error); 361 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 362 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 363 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 364 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 365 366 pubkey_cleanup(&authctxt); 367 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 368 369 /* if the user wants to use the none cipher do it */ 370 /* post authentication and only if the right conditions are met */ 371 /* both of the NONE commands must be true and there must be no */ 372 /* tty allocated */ 373 if ((options.none_switch == 1) && (options.none_enabled == 1)) 374 { 375 if (!tty_flag) /* no null on tty sessions */ 376 { 377 debug("Requesting none rekeying..."); 378 myproposal[PROPOSAL_ENC_ALGS_STOC] = "none"; 379 myproposal[PROPOSAL_ENC_ALGS_CTOS] = "none"; 380 kex_prop2buf(&xxx_kex->my,myproposal); 381 packet_request_rekeying(); 382 fprintf(stderr, "WARNING: ENABLED NONE CIPHER\n"); 383 } 384 else 385 { 386 /* requested NONE cipher when in a tty */ 387 debug("Cannot switch to NONE cipher with tty allocated"); 388 fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n"); 389 } 390 } 391 debug("Authentication succeeded (%s).", authctxt.method->name); 392 } 393 394 void 395 userauth(Authctxt *authctxt, char *authlist) 396 { 397 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 398 authctxt->method->cleanup(authctxt); 399 400 if (authctxt->methoddata) { 401 xfree(authctxt->methoddata); 402 authctxt->methoddata = NULL; 403 } 404 if (authlist == NULL) { 405 authlist = authctxt->authlist; 406 } else { 407 if (authctxt->authlist) 408 xfree(authctxt->authlist); 409 authctxt->authlist = authlist; 410 } 411 for (;;) { 412 Authmethod *method = authmethod_get(authlist); 413 if (method == NULL) 414 fatal("Permission denied (%s).", authlist); 415 authctxt->method = method; 416 417 /* reset the per method handler */ 418 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 419 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 420 421 /* and try new method */ 422 if (method->userauth(authctxt) != 0) { 423 debug2("we sent a %s packet, wait for reply", method->name); 424 break; 425 } else { 426 debug2("we did not send a packet, disable method"); 427 method->enabled = NULL; 428 } 429 } 430 } 431 432 /* ARGSUSED */ 433 void 434 input_userauth_error(int type, u_int32_t seq, void *ctxt) 435 { 436 fatal("input_userauth_error: bad message during authentication: " 437 "type %d", type); 438 } 439 440 /* ARGSUSED */ 441 void 442 input_userauth_banner(int type, u_int32_t seq, void *ctxt) 443 { 444 char *msg, *raw, *lang; 445 u_int len; 446 447 debug3("input_userauth_banner"); 448 raw = packet_get_string(&len); 449 lang = packet_get_string(NULL); 450 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) { 451 if (len > 65536) 452 len = 65536; 453 msg = xmalloc(len * 4 + 1); /* max expansion from strnvis() */ 454 strvisx(msg, raw, len, VIS_SAFE|VIS_OCTAL); 455 fprintf(stderr, "%s", msg); 456 xfree(msg); 457 } 458 xfree(raw); 459 xfree(lang); 460 } 461 462 /* ARGSUSED */ 463 void 464 input_userauth_success(int type, u_int32_t seq, void *ctxt) 465 { 466 Authctxt *authctxt = ctxt; 467 if (authctxt == NULL) 468 fatal("input_userauth_success: no authentication context"); 469 if (authctxt->authlist) { 470 xfree(authctxt->authlist); 471 authctxt->authlist = NULL; 472 } 473 if (authctxt->methoddata) { 474 xfree(authctxt->methoddata); 475 authctxt->methoddata = NULL; 476 } 477 authctxt->success = 1; /* break out */ 478 } 479 480 /* ARGSUSED */ 481 void 482 input_userauth_failure(int type, u_int32_t seq, void *ctxt) 483 { 484 Authctxt *authctxt = ctxt; 485 char *authlist = NULL; 486 int partial; 487 488 if (authctxt == NULL) 489 fatal("input_userauth_failure: no authentication context"); 490 491 authlist = packet_get_string(NULL); 492 partial = packet_get_char(); 493 packet_check_eom(); 494 495 if (partial != 0) 496 logit("Authenticated with partial success."); 497 debug("Authentications that can continue: %s", authlist); 498 499 userauth(authctxt, authlist); 500 } 501 502 /* ARGSUSED */ 503 void 504 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 505 { 506 Authctxt *authctxt = ctxt; 507 Key *key = NULL; 508 Identity *id = NULL; 509 Buffer b; 510 int pktype, sent = 0; 511 u_int alen, blen; 512 char *pkalg, *fp; 513 u_char *pkblob; 514 515 if (authctxt == NULL) 516 fatal("input_userauth_pk_ok: no authentication context"); 517 if (datafellows & SSH_BUG_PKOK) { 518 /* this is similar to SSH_BUG_PKAUTH */ 519 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 520 pkblob = packet_get_string(&blen); 521 buffer_init(&b); 522 buffer_append(&b, pkblob, blen); 523 pkalg = buffer_get_string(&b, &alen); 524 buffer_free(&b); 525 } else { 526 pkalg = packet_get_string(&alen); 527 pkblob = packet_get_string(&blen); 528 } 529 packet_check_eom(); 530 531 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 532 533 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 534 debug("unknown pkalg %s", pkalg); 535 goto done; 536 } 537 if ((key = key_from_blob(pkblob, blen)) == NULL) { 538 debug("no key from blob. pkalg %s", pkalg); 539 goto done; 540 } 541 if (key->type != pktype) { 542 error("input_userauth_pk_ok: type mismatch " 543 "for decoded key (received %d, expected %d)", 544 key->type, pktype); 545 goto done; 546 } 547 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 548 debug2("input_userauth_pk_ok: fp %s", fp); 549 xfree(fp); 550 551 /* 552 * search keys in the reverse order, because last candidate has been 553 * moved to the end of the queue. this also avoids confusion by 554 * duplicate keys 555 */ 556 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 557 if (key_equal(key, id->key)) { 558 sent = sign_and_send_pubkey(authctxt, id); 559 break; 560 } 561 } 562 done: 563 if (key != NULL) 564 key_free(key); 565 xfree(pkalg); 566 xfree(pkblob); 567 568 /* try another method if we did not send a packet */ 569 if (sent == 0) 570 userauth(authctxt, NULL); 571 } 572 573 #ifdef GSSAPI 574 int 575 userauth_gssapi(Authctxt *authctxt) 576 { 577 Gssctxt *gssctxt = NULL; 578 static gss_OID_set gss_supported = NULL; 579 static u_int mech = 0; 580 OM_uint32 min; 581 int ok = 0; 582 583 /* Try one GSSAPI method at a time, rather than sending them all at 584 * once. */ 585 586 if (gss_supported == NULL) 587 gss_indicate_mechs(&min, &gss_supported); 588 589 /* Check to see if the mechanism is usable before we offer it */ 590 while (mech < gss_supported->count && !ok) { 591 /* My DER encoding requires length<128 */ 592 if (gss_supported->elements[mech].length < 128 && 593 ssh_gssapi_check_mechanism(&gssctxt, 594 &gss_supported->elements[mech], authctxt->host)) { 595 ok = 1; /* Mechanism works */ 596 } else { 597 mech++; 598 } 599 } 600 601 if (!ok) { 602 ssh_gssapi_delete_ctx(&gssctxt); 603 return 0; 604 } 605 606 authctxt->methoddata=(void *)gssctxt; 607 608 packet_start(SSH2_MSG_USERAUTH_REQUEST); 609 packet_put_cstring(authctxt->server_user); 610 packet_put_cstring(authctxt->service); 611 packet_put_cstring(authctxt->method->name); 612 613 packet_put_int(1); 614 615 packet_put_int((gss_supported->elements[mech].length) + 2); 616 packet_put_char(SSH_GSS_OIDTYPE); 617 packet_put_char(gss_supported->elements[mech].length); 618 packet_put_raw(gss_supported->elements[mech].elements, 619 gss_supported->elements[mech].length); 620 621 packet_send(); 622 623 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 624 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 625 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 626 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 627 628 mech++; /* Move along to next candidate */ 629 630 return 1; 631 } 632 633 static OM_uint32 634 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 635 { 636 Authctxt *authctxt = ctxt; 637 Gssctxt *gssctxt = authctxt->methoddata; 638 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 639 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 640 gss_buffer_desc gssbuf; 641 OM_uint32 status, ms, flags; 642 Buffer b; 643 644 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 645 recv_tok, &send_tok, &flags); 646 647 if (send_tok.length > 0) { 648 if (GSS_ERROR(status)) 649 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 650 else 651 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 652 653 packet_put_string(send_tok.value, send_tok.length); 654 packet_send(); 655 gss_release_buffer(&ms, &send_tok); 656 } 657 658 if (status == GSS_S_COMPLETE) { 659 /* send either complete or MIC, depending on mechanism */ 660 if (!(flags & GSS_C_INTEG_FLAG)) { 661 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 662 packet_send(); 663 } else { 664 ssh_gssapi_buildmic(&b, authctxt->server_user, 665 authctxt->service, "gssapi-with-mic"); 666 667 gssbuf.value = buffer_ptr(&b); 668 gssbuf.length = buffer_len(&b); 669 670 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 671 672 if (!GSS_ERROR(status)) { 673 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 674 packet_put_string(mic.value, mic.length); 675 676 packet_send(); 677 } 678 679 buffer_free(&b); 680 gss_release_buffer(&ms, &mic); 681 } 682 } 683 684 return status; 685 } 686 687 /* ARGSUSED */ 688 void 689 input_gssapi_response(int type, u_int32_t plen, void *ctxt) 690 { 691 Authctxt *authctxt = ctxt; 692 Gssctxt *gssctxt; 693 int oidlen; 694 char *oidv; 695 696 if (authctxt == NULL) 697 fatal("input_gssapi_response: no authentication context"); 698 gssctxt = authctxt->methoddata; 699 700 /* Setup our OID */ 701 oidv = packet_get_string(&oidlen); 702 703 if (oidlen <= 2 || 704 oidv[0] != SSH_GSS_OIDTYPE || 705 oidv[1] != oidlen - 2) { 706 xfree(oidv); 707 debug("Badly encoded mechanism OID received"); 708 userauth(authctxt, NULL); 709 return; 710 } 711 712 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 713 fatal("Server returned different OID than expected"); 714 715 packet_check_eom(); 716 717 xfree(oidv); 718 719 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 720 /* Start again with next method on list */ 721 debug("Trying to start again"); 722 userauth(authctxt, NULL); 723 return; 724 } 725 } 726 727 /* ARGSUSED */ 728 void 729 input_gssapi_token(int type, u_int32_t plen, void *ctxt) 730 { 731 Authctxt *authctxt = ctxt; 732 gss_buffer_desc recv_tok; 733 OM_uint32 status; 734 u_int slen; 735 736 if (authctxt == NULL) 737 fatal("input_gssapi_response: no authentication context"); 738 739 recv_tok.value = packet_get_string(&slen); 740 recv_tok.length = slen; /* safe typecast */ 741 742 packet_check_eom(); 743 744 status = process_gssapi_token(ctxt, &recv_tok); 745 746 xfree(recv_tok.value); 747 748 if (GSS_ERROR(status)) { 749 /* Start again with the next method in the list */ 750 userauth(authctxt, NULL); 751 return; 752 } 753 } 754 755 /* ARGSUSED */ 756 void 757 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 758 { 759 Authctxt *authctxt = ctxt; 760 Gssctxt *gssctxt; 761 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 762 gss_buffer_desc recv_tok; 763 OM_uint32 status, ms; 764 u_int len; 765 766 if (authctxt == NULL) 767 fatal("input_gssapi_response: no authentication context"); 768 gssctxt = authctxt->methoddata; 769 770 recv_tok.value = packet_get_string(&len); 771 recv_tok.length = len; 772 773 packet_check_eom(); 774 775 /* Stick it into GSSAPI and see what it says */ 776 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 777 &recv_tok, &send_tok, NULL); 778 779 xfree(recv_tok.value); 780 gss_release_buffer(&ms, &send_tok); 781 782 /* Server will be returning a failed packet after this one */ 783 } 784 785 /* ARGSUSED */ 786 void 787 input_gssapi_error(int type, u_int32_t plen, void *ctxt) 788 { 789 OM_uint32 maj, min; 790 char *msg; 791 char *lang; 792 793 maj=packet_get_int(); 794 min=packet_get_int(); 795 msg=packet_get_string(NULL); 796 lang=packet_get_string(NULL); 797 798 packet_check_eom(); 799 800 debug("Server GSSAPI Error:\n%s", msg); 801 xfree(msg); 802 xfree(lang); 803 } 804 #endif /* GSSAPI */ 805 806 int 807 userauth_none(Authctxt *authctxt) 808 { 809 /* initial userauth request */ 810 packet_start(SSH2_MSG_USERAUTH_REQUEST); 811 packet_put_cstring(authctxt->server_user); 812 packet_put_cstring(authctxt->service); 813 packet_put_cstring(authctxt->method->name); 814 packet_send(); 815 return 1; 816 } 817 818 int 819 userauth_passwd(Authctxt *authctxt) 820 { 821 static int attempt = 0; 822 char prompt[150]; 823 char *password; 824 825 if (attempt++ >= options.number_of_password_prompts) 826 return 0; 827 828 if (attempt != 1) 829 error("Permission denied, please try again."); 830 831 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 832 authctxt->server_user, authctxt->host); 833 password = read_passphrase(prompt, 0); 834 packet_start(SSH2_MSG_USERAUTH_REQUEST); 835 packet_put_cstring(authctxt->server_user); 836 packet_put_cstring(authctxt->service); 837 packet_put_cstring(authctxt->method->name); 838 packet_put_char(0); 839 packet_put_cstring(password); 840 memset(password, 0, strlen(password)); 841 xfree(password); 842 packet_add_padding(64); 843 packet_send(); 844 845 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 846 &input_userauth_passwd_changereq); 847 848 return 1; 849 } 850 851 /* 852 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 853 */ 854 /* ARGSUSED */ 855 void 856 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 857 { 858 Authctxt *authctxt = ctxt; 859 char *info, *lang, *password = NULL, *retype = NULL; 860 char prompt[150]; 861 862 debug2("input_userauth_passwd_changereq"); 863 864 if (authctxt == NULL) 865 fatal("input_userauth_passwd_changereq: " 866 "no authentication context"); 867 868 info = packet_get_string(NULL); 869 lang = packet_get_string(NULL); 870 if (strlen(info) > 0) 871 logit("%s", info); 872 xfree(info); 873 xfree(lang); 874 packet_start(SSH2_MSG_USERAUTH_REQUEST); 875 packet_put_cstring(authctxt->server_user); 876 packet_put_cstring(authctxt->service); 877 packet_put_cstring(authctxt->method->name); 878 packet_put_char(1); /* additional info */ 879 snprintf(prompt, sizeof(prompt), 880 "Enter %.30s@%.128s's old password: ", 881 authctxt->server_user, authctxt->host); 882 password = read_passphrase(prompt, 0); 883 packet_put_cstring(password); 884 memset(password, 0, strlen(password)); 885 xfree(password); 886 password = NULL; 887 while (password == NULL) { 888 snprintf(prompt, sizeof(prompt), 889 "Enter %.30s@%.128s's new password: ", 890 authctxt->server_user, authctxt->host); 891 password = read_passphrase(prompt, RP_ALLOW_EOF); 892 if (password == NULL) { 893 /* bail out */ 894 return; 895 } 896 snprintf(prompt, sizeof(prompt), 897 "Retype %.30s@%.128s's new password: ", 898 authctxt->server_user, authctxt->host); 899 retype = read_passphrase(prompt, 0); 900 if (strcmp(password, retype) != 0) { 901 memset(password, 0, strlen(password)); 902 xfree(password); 903 logit("Mismatch; try again, EOF to quit."); 904 password = NULL; 905 } 906 memset(retype, 0, strlen(retype)); 907 xfree(retype); 908 } 909 packet_put_cstring(password); 910 memset(password, 0, strlen(password)); 911 xfree(password); 912 packet_add_padding(64); 913 packet_send(); 914 915 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 916 &input_userauth_passwd_changereq); 917 } 918 919 #ifdef JPAKE 920 static char * 921 pw_encrypt(const char *password, const char *crypt_scheme, const char *salt) 922 { 923 /* OpenBSD crypt(3) handles all of these */ 924 if (strcmp(crypt_scheme, "crypt") == 0 || 925 strcmp(crypt_scheme, "bcrypt") == 0 || 926 strcmp(crypt_scheme, "md5crypt") == 0 || 927 strcmp(crypt_scheme, "crypt-extended") == 0) 928 return xstrdup(crypt(password, salt)); 929 error("%s: unsupported password encryption scheme \"%.100s\"", 930 __func__, crypt_scheme); 931 return NULL; 932 } 933 934 static BIGNUM * 935 jpake_password_to_secret(Authctxt *authctxt, const char *crypt_scheme, 936 const char *salt) 937 { 938 char prompt[256], *password, *crypted; 939 u_char *secret; 940 u_int secret_len; 941 BIGNUM *ret; 942 943 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password (JPAKE): ", 944 authctxt->server_user, authctxt->host); 945 password = read_passphrase(prompt, 0); 946 947 if ((crypted = pw_encrypt(password, crypt_scheme, salt)) == NULL) { 948 logit("Disabling %s authentication", authctxt->method->name); 949 authctxt->method->enabled = NULL; 950 /* Continue with an empty password to fail gracefully */ 951 crypted = xstrdup(""); 952 } 953 954 #ifdef JPAKE_DEBUG 955 debug3("%s: salt = %s", __func__, salt); 956 debug3("%s: scheme = %s", __func__, crypt_scheme); 957 debug3("%s: crypted = %s", __func__, crypted); 958 #endif 959 960 if (hash_buffer(crypted, strlen(crypted), EVP_sha256(), 961 &secret, &secret_len) != 0) 962 fatal("%s: hash_buffer", __func__); 963 964 bzero(password, strlen(password)); 965 bzero(crypted, strlen(crypted)); 966 xfree(password); 967 xfree(crypted); 968 969 if ((ret = BN_bin2bn(secret, secret_len, NULL)) == NULL) 970 fatal("%s: BN_bin2bn (secret)", __func__); 971 bzero(secret, secret_len); 972 xfree(secret); 973 974 return ret; 975 } 976 977 /* ARGSUSED */ 978 void 979 input_userauth_jpake_server_step1(int type, u_int32_t seq, void *ctxt) 980 { 981 Authctxt *authctxt = ctxt; 982 struct jpake_ctx *pctx = authctxt->methoddata; 983 u_char *x3_proof, *x4_proof, *x2_s_proof; 984 u_int x3_proof_len, x4_proof_len, x2_s_proof_len; 985 char *crypt_scheme, *salt; 986 987 /* Disable this message */ 988 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, NULL); 989 990 if ((pctx->g_x3 = BN_new()) == NULL || 991 (pctx->g_x4 = BN_new()) == NULL) 992 fatal("%s: BN_new", __func__); 993 994 /* Fetch step 1 values */ 995 crypt_scheme = packet_get_string(NULL); 996 salt = packet_get_string(NULL); 997 pctx->server_id = packet_get_string(&pctx->server_id_len); 998 packet_get_bignum2(pctx->g_x3); 999 packet_get_bignum2(pctx->g_x4); 1000 x3_proof = packet_get_string(&x3_proof_len); 1001 x4_proof = packet_get_string(&x4_proof_len); 1002 packet_check_eom(); 1003 1004 JPAKE_DEBUG_CTX((pctx, "step 1 received in %s", __func__)); 1005 1006 /* Obtain password and derive secret */ 1007 pctx->s = jpake_password_to_secret(authctxt, crypt_scheme, salt); 1008 bzero(crypt_scheme, strlen(crypt_scheme)); 1009 bzero(salt, strlen(salt)); 1010 xfree(crypt_scheme); 1011 xfree(salt); 1012 JPAKE_DEBUG_BN((pctx->s, "%s: s = ", __func__)); 1013 1014 /* Calculate step 2 values */ 1015 jpake_step2(pctx->grp, pctx->s, pctx->g_x1, 1016 pctx->g_x3, pctx->g_x4, pctx->x2, 1017 pctx->server_id, pctx->server_id_len, 1018 pctx->client_id, pctx->client_id_len, 1019 x3_proof, x3_proof_len, 1020 x4_proof, x4_proof_len, 1021 &pctx->a, 1022 &x2_s_proof, &x2_s_proof_len); 1023 1024 bzero(x3_proof, x3_proof_len); 1025 bzero(x4_proof, x4_proof_len); 1026 xfree(x3_proof); 1027 xfree(x4_proof); 1028 1029 JPAKE_DEBUG_CTX((pctx, "step 2 sending in %s", __func__)); 1030 1031 /* Send values for step 2 */ 1032 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP2); 1033 packet_put_bignum2(pctx->a); 1034 packet_put_string(x2_s_proof, x2_s_proof_len); 1035 packet_send(); 1036 1037 bzero(x2_s_proof, x2_s_proof_len); 1038 xfree(x2_s_proof); 1039 1040 /* Expect step 2 packet from peer */ 1041 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, 1042 input_userauth_jpake_server_step2); 1043 } 1044 1045 /* ARGSUSED */ 1046 void 1047 input_userauth_jpake_server_step2(int type, u_int32_t seq, void *ctxt) 1048 { 1049 Authctxt *authctxt = ctxt; 1050 struct jpake_ctx *pctx = authctxt->methoddata; 1051 u_char *x4_s_proof; 1052 u_int x4_s_proof_len; 1053 1054 /* Disable this message */ 1055 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP2, NULL); 1056 1057 if ((pctx->b = BN_new()) == NULL) 1058 fatal("%s: BN_new", __func__); 1059 1060 /* Fetch step 2 values */ 1061 packet_get_bignum2(pctx->b); 1062 x4_s_proof = packet_get_string(&x4_s_proof_len); 1063 packet_check_eom(); 1064 1065 JPAKE_DEBUG_CTX((pctx, "step 2 received in %s", __func__)); 1066 1067 /* Derive shared key and calculate confirmation hash */ 1068 jpake_key_confirm(pctx->grp, pctx->s, pctx->b, 1069 pctx->x2, pctx->g_x1, pctx->g_x2, pctx->g_x3, pctx->g_x4, 1070 pctx->client_id, pctx->client_id_len, 1071 pctx->server_id, pctx->server_id_len, 1072 session_id2, session_id2_len, 1073 x4_s_proof, x4_s_proof_len, 1074 &pctx->k, 1075 &pctx->h_k_cid_sessid, &pctx->h_k_cid_sessid_len); 1076 1077 bzero(x4_s_proof, x4_s_proof_len); 1078 xfree(x4_s_proof); 1079 1080 JPAKE_DEBUG_CTX((pctx, "confirm sending in %s", __func__)); 1081 1082 /* Send key confirmation proof */ 1083 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_CONFIRM); 1084 packet_put_string(pctx->h_k_cid_sessid, pctx->h_k_cid_sessid_len); 1085 packet_send(); 1086 1087 /* Expect confirmation from peer */ 1088 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, 1089 input_userauth_jpake_server_confirm); 1090 } 1091 1092 /* ARGSUSED */ 1093 void 1094 input_userauth_jpake_server_confirm(int type, u_int32_t seq, void *ctxt) 1095 { 1096 Authctxt *authctxt = ctxt; 1097 struct jpake_ctx *pctx = authctxt->methoddata; 1098 1099 /* Disable this message */ 1100 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_CONFIRM, NULL); 1101 1102 pctx->h_k_sid_sessid = packet_get_string(&pctx->h_k_sid_sessid_len); 1103 packet_check_eom(); 1104 1105 JPAKE_DEBUG_CTX((pctx, "confirm received in %s", __func__)); 1106 1107 /* Verify expected confirmation hash */ 1108 if (jpake_check_confirm(pctx->k, 1109 pctx->server_id, pctx->server_id_len, 1110 session_id2, session_id2_len, 1111 pctx->h_k_sid_sessid, pctx->h_k_sid_sessid_len) == 1) 1112 debug("%s: %s success", __func__, authctxt->method->name); 1113 else { 1114 debug("%s: confirmation mismatch", __func__); 1115 /* XXX stash this so if auth succeeds then we can warn/kill */ 1116 } 1117 1118 userauth_jpake_cleanup(authctxt); 1119 } 1120 #endif /* JPAKE */ 1121 1122 static int 1123 identity_sign(Identity *id, u_char **sigp, u_int *lenp, 1124 u_char *data, u_int datalen) 1125 { 1126 Key *prv; 1127 int ret; 1128 1129 /* the agent supports this key */ 1130 if (id->ac) 1131 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 1132 data, datalen)); 1133 /* 1134 * we have already loaded the private key or 1135 * the private key is stored in external hardware 1136 */ 1137 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 1138 return (key_sign(id->key, sigp, lenp, data, datalen)); 1139 /* load the private key from the file */ 1140 if ((prv = load_identity_file(id->filename)) == NULL) 1141 return (-1); 1142 ret = key_sign(prv, sigp, lenp, data, datalen); 1143 key_free(prv); 1144 return (ret); 1145 } 1146 1147 static int 1148 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1149 { 1150 Buffer b; 1151 u_char *blob, *signature; 1152 u_int bloblen, slen; 1153 u_int skip = 0; 1154 int ret = -1; 1155 int have_sig = 1; 1156 1157 debug3("sign_and_send_pubkey"); 1158 1159 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1160 /* we cannot handle this key */ 1161 debug3("sign_and_send_pubkey: cannot handle key"); 1162 return 0; 1163 } 1164 /* data to be signed */ 1165 buffer_init(&b); 1166 if (datafellows & SSH_OLD_SESSIONID) { 1167 buffer_append(&b, session_id2, session_id2_len); 1168 skip = session_id2_len; 1169 } else { 1170 buffer_put_string(&b, session_id2, session_id2_len); 1171 skip = buffer_len(&b); 1172 } 1173 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1174 buffer_put_cstring(&b, authctxt->server_user); 1175 buffer_put_cstring(&b, 1176 datafellows & SSH_BUG_PKSERVICE ? 1177 "ssh-userauth" : 1178 authctxt->service); 1179 if (datafellows & SSH_BUG_PKAUTH) { 1180 buffer_put_char(&b, have_sig); 1181 } else { 1182 buffer_put_cstring(&b, authctxt->method->name); 1183 buffer_put_char(&b, have_sig); 1184 buffer_put_cstring(&b, key_ssh_name(id->key)); 1185 } 1186 buffer_put_string(&b, blob, bloblen); 1187 1188 /* generate signature */ 1189 ret = identity_sign(id, &signature, &slen, 1190 buffer_ptr(&b), buffer_len(&b)); 1191 if (ret == -1) { 1192 xfree(blob); 1193 buffer_free(&b); 1194 return 0; 1195 } 1196 #ifdef DEBUG_PK 1197 buffer_dump(&b); 1198 #endif 1199 if (datafellows & SSH_BUG_PKSERVICE) { 1200 buffer_clear(&b); 1201 buffer_append(&b, session_id2, session_id2_len); 1202 skip = session_id2_len; 1203 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1204 buffer_put_cstring(&b, authctxt->server_user); 1205 buffer_put_cstring(&b, authctxt->service); 1206 buffer_put_cstring(&b, authctxt->method->name); 1207 buffer_put_char(&b, have_sig); 1208 if (!(datafellows & SSH_BUG_PKAUTH)) 1209 buffer_put_cstring(&b, key_ssh_name(id->key)); 1210 buffer_put_string(&b, blob, bloblen); 1211 } 1212 xfree(blob); 1213 1214 /* append signature */ 1215 buffer_put_string(&b, signature, slen); 1216 xfree(signature); 1217 1218 /* skip session id and packet type */ 1219 if (buffer_len(&b) < skip + 1) 1220 fatal("userauth_pubkey: internal error"); 1221 buffer_consume(&b, skip + 1); 1222 1223 /* put remaining data from buffer into packet */ 1224 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1225 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1226 buffer_free(&b); 1227 packet_send(); 1228 1229 return 1; 1230 } 1231 1232 static int 1233 send_pubkey_test(Authctxt *authctxt, Identity *id) 1234 { 1235 u_char *blob; 1236 u_int bloblen, have_sig = 0; 1237 1238 debug3("send_pubkey_test"); 1239 1240 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1241 /* we cannot handle this key */ 1242 debug3("send_pubkey_test: cannot handle key"); 1243 return 0; 1244 } 1245 /* register callback for USERAUTH_PK_OK message */ 1246 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1247 1248 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1249 packet_put_cstring(authctxt->server_user); 1250 packet_put_cstring(authctxt->service); 1251 packet_put_cstring(authctxt->method->name); 1252 packet_put_char(have_sig); 1253 if (!(datafellows & SSH_BUG_PKAUTH)) 1254 packet_put_cstring(key_ssh_name(id->key)); 1255 packet_put_string(blob, bloblen); 1256 xfree(blob); 1257 packet_send(); 1258 return 1; 1259 } 1260 1261 static Key * 1262 load_identity_file(char *filename) 1263 { 1264 Key *private; 1265 char prompt[300], *passphrase; 1266 int perm_ok, quit, i; 1267 struct stat st; 1268 1269 if (stat(filename, &st) < 0) { 1270 debug3("no such identity: %s", filename); 1271 return NULL; 1272 } 1273 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 1274 if (!perm_ok) 1275 return NULL; 1276 if (private == NULL) { 1277 if (options.batch_mode) 1278 return NULL; 1279 snprintf(prompt, sizeof prompt, 1280 "Enter passphrase for key '%.100s': ", filename); 1281 for (i = 0; i < options.number_of_password_prompts; i++) { 1282 passphrase = read_passphrase(prompt, 0); 1283 if (strcmp(passphrase, "") != 0) { 1284 private = key_load_private_type(KEY_UNSPEC, 1285 filename, passphrase, NULL, NULL); 1286 quit = 0; 1287 } else { 1288 debug2("no passphrase given, try next key"); 1289 quit = 1; 1290 } 1291 memset(passphrase, 0, strlen(passphrase)); 1292 xfree(passphrase); 1293 if (private != NULL || quit) 1294 break; 1295 debug2("bad passphrase given, try again..."); 1296 } 1297 } 1298 return private; 1299 } 1300 1301 /* 1302 * try keys in the following order: 1303 * 1. agent keys that are found in the config file 1304 * 2. other agent keys 1305 * 3. keys that are only listed in the config file 1306 */ 1307 static void 1308 pubkey_prepare(Authctxt *authctxt) 1309 { 1310 Identity *id; 1311 Idlist agent, files, *preferred; 1312 Key *key; 1313 AuthenticationConnection *ac; 1314 char *comment; 1315 int i, found; 1316 1317 TAILQ_INIT(&agent); /* keys from the agent */ 1318 TAILQ_INIT(&files); /* keys from the config file */ 1319 preferred = &authctxt->keys; 1320 TAILQ_INIT(preferred); /* preferred order of keys */ 1321 1322 /* list of keys stored in the filesystem */ 1323 for (i = 0; i < options.num_identity_files; i++) { 1324 key = options.identity_keys[i]; 1325 if (key && key->type == KEY_RSA1) 1326 continue; 1327 options.identity_keys[i] = NULL; 1328 id = xcalloc(1, sizeof(*id)); 1329 id->key = key; 1330 id->filename = xstrdup(options.identity_files[i]); 1331 TAILQ_INSERT_TAIL(&files, id, next); 1332 } 1333 /* list of keys supported by the agent */ 1334 if ((ac = ssh_get_authentication_connection())) { 1335 for (key = ssh_get_first_identity(ac, &comment, 2); 1336 key != NULL; 1337 key = ssh_get_next_identity(ac, &comment, 2)) { 1338 found = 0; 1339 TAILQ_FOREACH(id, &files, next) { 1340 /* agent keys from the config file are preferred */ 1341 if (key_equal(key, id->key)) { 1342 key_free(key); 1343 xfree(comment); 1344 TAILQ_REMOVE(&files, id, next); 1345 TAILQ_INSERT_TAIL(preferred, id, next); 1346 id->ac = ac; 1347 found = 1; 1348 break; 1349 } 1350 } 1351 if (!found && !options.identities_only) { 1352 id = xcalloc(1, sizeof(*id)); 1353 id->key = key; 1354 id->filename = comment; 1355 id->ac = ac; 1356 TAILQ_INSERT_TAIL(&agent, id, next); 1357 } 1358 } 1359 /* append remaining agent keys */ 1360 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1361 TAILQ_REMOVE(&agent, id, next); 1362 TAILQ_INSERT_TAIL(preferred, id, next); 1363 } 1364 authctxt->agent = ac; 1365 } 1366 /* append remaining keys from the config file */ 1367 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1368 TAILQ_REMOVE(&files, id, next); 1369 TAILQ_INSERT_TAIL(preferred, id, next); 1370 } 1371 TAILQ_FOREACH(id, preferred, next) { 1372 debug2("key: %s (%p)", id->filename, id->key); 1373 } 1374 } 1375 1376 static void 1377 pubkey_cleanup(Authctxt *authctxt) 1378 { 1379 Identity *id; 1380 1381 if (authctxt->agent != NULL) 1382 ssh_close_authentication_connection(authctxt->agent); 1383 for (id = TAILQ_FIRST(&authctxt->keys); id; 1384 id = TAILQ_FIRST(&authctxt->keys)) { 1385 TAILQ_REMOVE(&authctxt->keys, id, next); 1386 if (id->key) 1387 key_free(id->key); 1388 if (id->filename) 1389 xfree(id->filename); 1390 xfree(id); 1391 } 1392 } 1393 1394 int 1395 userauth_pubkey(Authctxt *authctxt) 1396 { 1397 Identity *id; 1398 int sent = 0; 1399 1400 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1401 if (id->tried++) 1402 return (0); 1403 /* move key to the end of the queue */ 1404 TAILQ_REMOVE(&authctxt->keys, id, next); 1405 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1406 /* 1407 * send a test message if we have the public key. for 1408 * encrypted keys we cannot do this and have to load the 1409 * private key instead 1410 */ 1411 if (id->key && id->key->type != KEY_RSA1) { 1412 debug("Offering public key: %s", id->filename); 1413 sent = send_pubkey_test(authctxt, id); 1414 } else if (id->key == NULL) { 1415 debug("Trying private key: %s", id->filename); 1416 id->key = load_identity_file(id->filename); 1417 if (id->key != NULL) { 1418 id->isprivate = 1; 1419 sent = sign_and_send_pubkey(authctxt, id); 1420 key_free(id->key); 1421 id->key = NULL; 1422 } 1423 } 1424 if (sent) 1425 return (sent); 1426 } 1427 return (0); 1428 } 1429 1430 /* 1431 * Send userauth request message specifying keyboard-interactive method. 1432 */ 1433 int 1434 userauth_kbdint(Authctxt *authctxt) 1435 { 1436 static int attempt = 0; 1437 1438 if (attempt++ >= options.number_of_password_prompts) 1439 return 0; 1440 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1441 if (attempt > 1 && !authctxt->info_req_seen) { 1442 debug3("userauth_kbdint: disable: no info_req_seen"); 1443 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1444 return 0; 1445 } 1446 1447 debug2("userauth_kbdint"); 1448 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1449 packet_put_cstring(authctxt->server_user); 1450 packet_put_cstring(authctxt->service); 1451 packet_put_cstring(authctxt->method->name); 1452 packet_put_cstring(""); /* lang */ 1453 packet_put_cstring(options.kbd_interactive_devices ? 1454 options.kbd_interactive_devices : ""); 1455 packet_send(); 1456 1457 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1458 return 1; 1459 } 1460 1461 /* 1462 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1463 */ 1464 void 1465 input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1466 { 1467 Authctxt *authctxt = ctxt; 1468 char *name, *inst, *lang, *prompt, *response; 1469 u_int num_prompts, i; 1470 int echo = 0; 1471 1472 debug2("input_userauth_info_req"); 1473 1474 if (authctxt == NULL) 1475 fatal("input_userauth_info_req: no authentication context"); 1476 1477 authctxt->info_req_seen = 1; 1478 1479 name = packet_get_string(NULL); 1480 inst = packet_get_string(NULL); 1481 lang = packet_get_string(NULL); 1482 if (strlen(name) > 0) 1483 logit("%s", name); 1484 if (strlen(inst) > 0) 1485 logit("%s", inst); 1486 xfree(name); 1487 xfree(inst); 1488 xfree(lang); 1489 1490 num_prompts = packet_get_int(); 1491 /* 1492 * Begin to build info response packet based on prompts requested. 1493 * We commit to providing the correct number of responses, so if 1494 * further on we run into a problem that prevents this, we have to 1495 * be sure and clean this up and send a correct error response. 1496 */ 1497 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1498 packet_put_int(num_prompts); 1499 1500 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1501 for (i = 0; i < num_prompts; i++) { 1502 prompt = packet_get_string(NULL); 1503 echo = packet_get_char(); 1504 1505 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1506 1507 packet_put_cstring(response); 1508 memset(response, 0, strlen(response)); 1509 xfree(response); 1510 xfree(prompt); 1511 } 1512 packet_check_eom(); /* done with parsing incoming message. */ 1513 1514 packet_add_padding(64); 1515 packet_send(); 1516 } 1517 1518 static int 1519 ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1520 u_char *data, u_int datalen) 1521 { 1522 Buffer b; 1523 struct stat st; 1524 pid_t pid; 1525 int to[2], from[2], status, version = 2; 1526 1527 debug2("ssh_keysign called"); 1528 1529 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1530 error("ssh_keysign: no installed: %s", strerror(errno)); 1531 return -1; 1532 } 1533 if (fflush(stdout) != 0) 1534 error("ssh_keysign: fflush: %s", strerror(errno)); 1535 if (pipe(to) < 0) { 1536 error("ssh_keysign: pipe: %s", strerror(errno)); 1537 return -1; 1538 } 1539 if (pipe(from) < 0) { 1540 error("ssh_keysign: pipe: %s", strerror(errno)); 1541 return -1; 1542 } 1543 if ((pid = fork()) < 0) { 1544 error("ssh_keysign: fork: %s", strerror(errno)); 1545 return -1; 1546 } 1547 if (pid == 0) { 1548 permanently_drop_suid(getuid()); 1549 close(from[0]); 1550 if (dup2(from[1], STDOUT_FILENO) < 0) 1551 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1552 close(to[1]); 1553 if (dup2(to[0], STDIN_FILENO) < 0) 1554 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1555 close(from[1]); 1556 close(to[0]); 1557 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1558 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1559 strerror(errno)); 1560 } 1561 close(from[1]); 1562 close(to[0]); 1563 1564 buffer_init(&b); 1565 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1566 buffer_put_string(&b, data, datalen); 1567 if (ssh_msg_send(to[1], version, &b) == -1) 1568 fatal("ssh_keysign: couldn't send request"); 1569 1570 if (ssh_msg_recv(from[0], &b) < 0) { 1571 error("ssh_keysign: no reply"); 1572 buffer_free(&b); 1573 return -1; 1574 } 1575 close(from[0]); 1576 close(to[1]); 1577 1578 while (waitpid(pid, &status, 0) < 0) 1579 if (errno != EINTR) 1580 break; 1581 1582 if (buffer_get_char(&b) != version) { 1583 error("ssh_keysign: bad version"); 1584 buffer_free(&b); 1585 return -1; 1586 } 1587 *sigp = buffer_get_string(&b, lenp); 1588 buffer_free(&b); 1589 1590 return 0; 1591 } 1592 1593 int 1594 userauth_hostbased(Authctxt *authctxt) 1595 { 1596 Key *private = NULL; 1597 Sensitive *sensitive = authctxt->sensitive; 1598 Buffer b; 1599 u_char *signature, *blob; 1600 char *chost, *pkalg, *p, myname[NI_MAXHOST]; 1601 const char *service; 1602 u_int blen, slen; 1603 int ok, i, len, found = 0; 1604 1605 /* check for a useful key */ 1606 for (i = 0; i < sensitive->nkeys; i++) { 1607 private = sensitive->keys[i]; 1608 if (private && private->type != KEY_RSA1) { 1609 found = 1; 1610 /* we take and free the key */ 1611 sensitive->keys[i] = NULL; 1612 break; 1613 } 1614 } 1615 if (!found) { 1616 debug("No more client hostkeys for hostbased authentication."); 1617 return 0; 1618 } 1619 if (key_to_blob(private, &blob, &blen) == 0) { 1620 key_free(private); 1621 return 0; 1622 } 1623 /* figure out a name for the client host */ 1624 p = NULL; 1625 if (packet_connection_is_on_socket()) 1626 p = get_local_name(packet_get_connection_in()); 1627 if (p == NULL) { 1628 if (gethostname(myname, sizeof(myname)) == -1) { 1629 verbose("userauth_hostbased: gethostname: %s", 1630 strerror(errno)); 1631 } else 1632 p = xstrdup(myname); 1633 } 1634 if (p == NULL) { 1635 error("userauth_hostbased: cannot get local ipaddr/name"); 1636 key_free(private); 1637 xfree(blob); 1638 return 0; 1639 } 1640 len = strlen(p) + 2; 1641 xasprintf(&chost, "%s.", p); 1642 debug2("userauth_hostbased: chost %s", chost); 1643 xfree(p); 1644 1645 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1646 authctxt->service; 1647 pkalg = xstrdup(key_ssh_name(private)); 1648 buffer_init(&b); 1649 /* construct data */ 1650 buffer_put_string(&b, session_id2, session_id2_len); 1651 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1652 buffer_put_cstring(&b, authctxt->server_user); 1653 buffer_put_cstring(&b, service); 1654 buffer_put_cstring(&b, authctxt->method->name); 1655 buffer_put_cstring(&b, pkalg); 1656 buffer_put_string(&b, blob, blen); 1657 buffer_put_cstring(&b, chost); 1658 buffer_put_cstring(&b, authctxt->local_user); 1659 #ifdef DEBUG_PK 1660 buffer_dump(&b); 1661 #endif 1662 if (sensitive->external_keysign) 1663 ok = ssh_keysign(private, &signature, &slen, 1664 buffer_ptr(&b), buffer_len(&b)); 1665 else 1666 ok = key_sign(private, &signature, &slen, 1667 buffer_ptr(&b), buffer_len(&b)); 1668 key_free(private); 1669 buffer_free(&b); 1670 if (ok != 0) { 1671 error("key_sign failed"); 1672 xfree(chost); 1673 xfree(pkalg); 1674 xfree(blob); 1675 return 0; 1676 } 1677 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1678 packet_put_cstring(authctxt->server_user); 1679 packet_put_cstring(authctxt->service); 1680 packet_put_cstring(authctxt->method->name); 1681 packet_put_cstring(pkalg); 1682 packet_put_string(blob, blen); 1683 packet_put_cstring(chost); 1684 packet_put_cstring(authctxt->local_user); 1685 packet_put_string(signature, slen); 1686 memset(signature, 's', slen); 1687 xfree(signature); 1688 xfree(chost); 1689 xfree(pkalg); 1690 xfree(blob); 1691 1692 packet_send(); 1693 return 1; 1694 } 1695 1696 #ifdef JPAKE 1697 int 1698 userauth_jpake(Authctxt *authctxt) 1699 { 1700 struct jpake_ctx *pctx; 1701 u_char *x1_proof, *x2_proof; 1702 u_int x1_proof_len, x2_proof_len; 1703 static int attempt = 0; /* XXX share with userauth_password's? */ 1704 1705 if (attempt++ >= options.number_of_password_prompts) 1706 return 0; 1707 if (attempt != 1) 1708 error("Permission denied, please try again."); 1709 1710 if (authctxt->methoddata != NULL) 1711 fatal("%s: authctxt->methoddata already set (%p)", 1712 __func__, authctxt->methoddata); 1713 1714 authctxt->methoddata = pctx = jpake_new(); 1715 1716 /* 1717 * Send request immediately, to get the protocol going while 1718 * we do the initial computations. 1719 */ 1720 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1721 packet_put_cstring(authctxt->server_user); 1722 packet_put_cstring(authctxt->service); 1723 packet_put_cstring(authctxt->method->name); 1724 packet_send(); 1725 packet_write_wait(); 1726 1727 jpake_step1(pctx->grp, 1728 &pctx->client_id, &pctx->client_id_len, 1729 &pctx->x1, &pctx->x2, &pctx->g_x1, &pctx->g_x2, 1730 &x1_proof, &x1_proof_len, 1731 &x2_proof, &x2_proof_len); 1732 1733 JPAKE_DEBUG_CTX((pctx, "step 1 sending in %s", __func__)); 1734 1735 packet_start(SSH2_MSG_USERAUTH_JPAKE_CLIENT_STEP1); 1736 packet_put_string(pctx->client_id, pctx->client_id_len); 1737 packet_put_bignum2(pctx->g_x1); 1738 packet_put_bignum2(pctx->g_x2); 1739 packet_put_string(x1_proof, x1_proof_len); 1740 packet_put_string(x2_proof, x2_proof_len); 1741 packet_send(); 1742 1743 bzero(x1_proof, x1_proof_len); 1744 bzero(x2_proof, x2_proof_len); 1745 xfree(x1_proof); 1746 xfree(x2_proof); 1747 1748 /* Expect step 1 packet from peer */ 1749 dispatch_set(SSH2_MSG_USERAUTH_JPAKE_SERVER_STEP1, 1750 input_userauth_jpake_server_step1); 1751 1752 return 1; 1753 } 1754 1755 void 1756 userauth_jpake_cleanup(Authctxt *authctxt) 1757 { 1758 debug3("%s: clean up", __func__); 1759 if (authctxt->methoddata != NULL) { 1760 jpake_free(authctxt->methoddata); 1761 authctxt->methoddata = NULL; 1762 } 1763 } 1764 #endif /* JPAKE */ 1765 1766 #if KRB5 1767 static int 1768 ssh_krb5_helper(krb5_data *ap) 1769 { 1770 krb5_context xcontext = NULL; /* XXX share with ssh1 */ 1771 krb5_auth_context xauth_context = NULL; 1772 1773 krb5_context *context; 1774 krb5_auth_context *auth_context; 1775 krb5_error_code problem; 1776 const char *tkfile; 1777 struct stat buf; 1778 krb5_ccache ccache = NULL; 1779 const char *remotehost; 1780 int ret; 1781 1782 memset(ap, 0, sizeof(*ap)); 1783 1784 context = &xcontext; 1785 auth_context = &xauth_context; 1786 1787 problem = krb5_init_context(context); 1788 if (problem) { 1789 debug("Kerberos v5: krb5_init_context failed"); 1790 ret = 0; 1791 goto out; 1792 } 1793 1794 tkfile = krb5_cc_default_name(*context); 1795 if (strncmp(tkfile, "FILE:", 5) == 0) 1796 tkfile += 5; 1797 1798 if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) { 1799 debug("Kerberos v5: could not get default ccache (permission denied)."); 1800 ret = 0; 1801 goto out; 1802 } 1803 1804 problem = krb5_cc_default(*context, &ccache); 1805 if (problem) { 1806 debug("Kerberos v5: krb5_cc_default failed: %s", 1807 krb5_get_err_text(*context, problem)); 1808 ret = 0; 1809 goto out; 1810 } 1811 1812 remotehost = get_canonical_hostname(1); 1813 1814 problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED, 1815 "host", remotehost, NULL, ccache, ap); 1816 if (problem) { 1817 debug("Kerberos v5: krb5_mk_req failed: %s", 1818 krb5_get_err_text(*context, problem)); 1819 ret = 0; 1820 goto out; 1821 } 1822 ret = 1; 1823 1824 out: 1825 if (ccache != NULL) 1826 krb5_cc_close(*context, ccache); 1827 if (*auth_context) 1828 krb5_auth_con_free(*context, *auth_context); 1829 if (*context) 1830 krb5_free_context(*context); 1831 return (ret); 1832 } 1833 1834 int 1835 userauth_kerberos(Authctxt *authctxt) 1836 { 1837 krb5_data ap; 1838 1839 if (ssh_krb5_helper(&ap) == 0) 1840 return (0); 1841 1842 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1843 packet_put_cstring(authctxt->server_user); 1844 packet_put_cstring(authctxt->service); 1845 packet_put_cstring(authctxt->method->name); 1846 packet_put_string(ap.data, ap.length); 1847 packet_send(); 1848 1849 krb5_data_free(&ap); 1850 return (1); 1851 } 1852 #endif 1853 1854 /* find auth method */ 1855 1856 /* 1857 * given auth method name, if configurable options permit this method fill 1858 * in auth_ident field and return true, otherwise return false. 1859 */ 1860 static int 1861 authmethod_is_enabled(Authmethod *method) 1862 { 1863 if (method == NULL) 1864 return 0; 1865 /* return false if options indicate this method is disabled */ 1866 if (method->enabled == NULL || *method->enabled == 0) 1867 return 0; 1868 /* return false if batch mode is enabled but method needs interactive mode */ 1869 if (method->batch_flag != NULL && *method->batch_flag != 0) 1870 return 0; 1871 return 1; 1872 } 1873 1874 static Authmethod * 1875 authmethod_lookup(const char *name) 1876 { 1877 Authmethod *method = NULL; 1878 if (name != NULL) 1879 for (method = authmethods; method->name != NULL; method++) 1880 if (strcmp(name, method->name) == 0) 1881 return method; 1882 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1883 return NULL; 1884 } 1885 1886 /* XXX internal state */ 1887 static Authmethod *current = NULL; 1888 static char *supported = NULL; 1889 static char *preferred = NULL; 1890 1891 /* 1892 * Given the authentication method list sent by the server, return the 1893 * next method we should try. If the server initially sends a nil list, 1894 * use a built-in default list. 1895 */ 1896 static Authmethod * 1897 authmethod_get(char *authlist) 1898 { 1899 char *name = NULL; 1900 u_int next; 1901 1902 /* Use a suitable default if we're passed a nil list. */ 1903 if (authlist == NULL || strlen(authlist) == 0) 1904 authlist = options.preferred_authentications; 1905 1906 if (supported == NULL || strcmp(authlist, supported) != 0) { 1907 debug3("start over, passed a different list %s", authlist); 1908 if (supported != NULL) 1909 xfree(supported); 1910 supported = xstrdup(authlist); 1911 preferred = options.preferred_authentications; 1912 debug3("preferred %s", preferred); 1913 current = NULL; 1914 } else if (current != NULL && authmethod_is_enabled(current)) 1915 return current; 1916 1917 for (;;) { 1918 if ((name = match_list(preferred, supported, &next)) == NULL) { 1919 debug("No more authentication methods to try."); 1920 current = NULL; 1921 return NULL; 1922 } 1923 preferred += next; 1924 debug3("authmethod_lookup %s", name); 1925 debug3("remaining preferred: %s", preferred); 1926 if ((current = authmethod_lookup(name)) != NULL && 1927 authmethod_is_enabled(current)) { 1928 debug3("authmethod_is_enabled %s", name); 1929 debug("Next authentication method: %s", name); 1930 return current; 1931 } 1932 } 1933 } 1934 1935 static char * 1936 authmethods_get(void) 1937 { 1938 Authmethod *method = NULL; 1939 Buffer b; 1940 char *list; 1941 1942 buffer_init(&b); 1943 for (method = authmethods; method->name != NULL; method++) { 1944 if (authmethod_is_enabled(method)) { 1945 if (buffer_len(&b) > 0) 1946 buffer_append(&b, ",", 1); 1947 buffer_append(&b, method->name, strlen(method->name)); 1948 } 1949 } 1950 buffer_append(&b, "\0", 1); 1951 list = xstrdup(buffer_ptr(&b)); 1952 buffer_free(&b); 1953 return list; 1954 } 1955 1956