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