1 /* $OpenBSD: sshconnect2.c,v 1.162 2006/08/30 00:06:51 dtucker Exp $ */ 2 /* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include <sys/types.h> 27 #include <sys/socket.h> 28 #include <sys/wait.h> 29 #include <sys/queue.h> 30 #include <sys/stat.h> 31 32 #include <errno.h> 33 #include <stdio.h> 34 #include <string.h> 35 #include <signal.h> 36 #include <pwd.h> 37 #include <unistd.h> 38 39 #include "xmalloc.h" 40 #include "ssh.h" 41 #include "ssh2.h" 42 #include "buffer.h" 43 #include "packet.h" 44 #include "compat.h" 45 #include "cipher.h" 46 #include "key.h" 47 #include "kex.h" 48 #include "myproposal.h" 49 #include "sshconnect.h" 50 #include "authfile.h" 51 #include "dh.h" 52 #include "authfd.h" 53 #include "log.h" 54 #include "readconf.h" 55 #include "misc.h" 56 #include "match.h" 57 #include "dispatch.h" 58 #include "canohost.h" 59 #include "msg.h" 60 #include "pathnames.h" 61 #include "uidswap.h" 62 63 #ifdef GSSAPI 64 #include "ssh-gss.h" 65 #endif 66 67 /* import */ 68 extern char *client_version_string; 69 extern char *server_version_string; 70 extern Options options; 71 72 /* 73 * SSH2 key exchange 74 */ 75 76 u_char *session_id2 = NULL; 77 u_int session_id2_len = 0; 78 79 char *xxx_host; 80 struct sockaddr *xxx_hostaddr; 81 82 Kex *xxx_kex = NULL; 83 84 static int 85 verify_host_key_callback(Key *hostkey) 86 { 87 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 88 fatal("Host key verification failed."); 89 return 0; 90 } 91 92 void 93 ssh_kex2(char *host, struct sockaddr *hostaddr) 94 { 95 Kex *kex; 96 97 xxx_host = host; 98 xxx_hostaddr = hostaddr; 99 100 if (options.ciphers == (char *)-1) { 101 logit("No valid ciphers for protocol version 2 given, using defaults."); 102 options.ciphers = NULL; 103 } 104 if (options.ciphers != NULL) { 105 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 106 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 107 } 108 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 109 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 110 myproposal[PROPOSAL_ENC_ALGS_STOC] = 111 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 112 if (options.compression) { 113 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 114 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 115 } else { 116 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 117 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 118 } 119 if (options.macs != NULL) { 120 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 121 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 122 } 123 if (options.hostkeyalgorithms != NULL) 124 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 125 options.hostkeyalgorithms; 126 127 if (options.rekey_limit) 128 packet_set_rekey_limit(options.rekey_limit); 129 130 /* start key exchange */ 131 kex = kex_setup(myproposal); 132 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 133 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 134 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 135 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 136 kex->client_version_string=client_version_string; 137 kex->server_version_string=server_version_string; 138 kex->verify_host_key=&verify_host_key_callback; 139 140 xxx_kex = kex; 141 142 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 143 144 session_id2 = kex->session_id; 145 session_id2_len = kex->session_id_len; 146 147 #ifdef DEBUG_KEXDH 148 /* send 1st encrypted/maced/compressed message */ 149 packet_start(SSH2_MSG_IGNORE); 150 packet_put_cstring("markus"); 151 packet_send(); 152 packet_write_wait(); 153 #endif 154 } 155 156 /* 157 * Authenticate user 158 */ 159 160 typedef struct Authctxt Authctxt; 161 typedef struct Authmethod Authmethod; 162 typedef struct identity Identity; 163 typedef struct idlist Idlist; 164 165 struct identity { 166 TAILQ_ENTRY(identity) next; 167 AuthenticationConnection *ac; /* set if agent supports key */ 168 Key *key; /* public/private key */ 169 char *filename; /* comment for agent-only keys */ 170 int tried; 171 int isprivate; /* key points to the private key */ 172 }; 173 TAILQ_HEAD(idlist, identity); 174 175 struct Authctxt { 176 const char *server_user; 177 const char *local_user; 178 const char *host; 179 const char *service; 180 Authmethod *method; 181 int success; 182 char *authlist; 183 /* pubkey */ 184 Idlist keys; 185 AuthenticationConnection *agent; 186 /* hostbased */ 187 Sensitive *sensitive; 188 /* kbd-interactive */ 189 int info_req_seen; 190 /* generic */ 191 void *methoddata; 192 }; 193 struct Authmethod { 194 char *name; /* string to compare against server's list */ 195 int (*userauth)(Authctxt *authctxt); 196 int *enabled; /* flag in option struct that enables method */ 197 int *batch_flag; /* flag in option struct that disables method */ 198 }; 199 200 void input_userauth_success(int, u_int32_t, void *); 201 void input_userauth_failure(int, u_int32_t, void *); 202 void input_userauth_banner(int, u_int32_t, void *); 203 void input_userauth_error(int, u_int32_t, void *); 204 void input_userauth_info_req(int, u_int32_t, void *); 205 void input_userauth_pk_ok(int, u_int32_t, void *); 206 void input_userauth_passwd_changereq(int, u_int32_t, void *); 207 208 int userauth_none(Authctxt *); 209 int userauth_pubkey(Authctxt *); 210 int userauth_passwd(Authctxt *); 211 int userauth_kbdint(Authctxt *); 212 int userauth_hostbased(Authctxt *); 213 int userauth_kerberos(Authctxt *); 214 215 #ifdef GSSAPI 216 int userauth_gssapi(Authctxt *authctxt); 217 void input_gssapi_response(int type, u_int32_t, void *); 218 void input_gssapi_token(int type, u_int32_t, void *); 219 void input_gssapi_hash(int type, u_int32_t, void *); 220 void input_gssapi_error(int, u_int32_t, void *); 221 void input_gssapi_errtok(int, u_int32_t, void *); 222 #endif 223 224 void userauth(Authctxt *, char *); 225 226 static int sign_and_send_pubkey(Authctxt *, Identity *); 227 static void pubkey_prepare(Authctxt *); 228 static void pubkey_cleanup(Authctxt *); 229 static Key *load_identity_file(char *); 230 231 static Authmethod *authmethod_get(char *authlist); 232 static Authmethod *authmethod_lookup(const char *name); 233 static char *authmethods_get(void); 234 235 Authmethod authmethods[] = { 236 #ifdef GSSAPI 237 {"gssapi-with-mic", 238 userauth_gssapi, 239 &options.gss_authentication, 240 NULL}, 241 #endif 242 {"hostbased", 243 userauth_hostbased, 244 &options.hostbased_authentication, 245 NULL}, 246 {"publickey", 247 userauth_pubkey, 248 &options.pubkey_authentication, 249 NULL}, 250 {"keyboard-interactive", 251 userauth_kbdint, 252 &options.kbd_interactive_authentication, 253 &options.batch_mode}, 254 {"password", 255 userauth_passwd, 256 &options.password_authentication, 257 &options.batch_mode}, 258 {"none", 259 userauth_none, 260 NULL, 261 NULL}, 262 {NULL, NULL, NULL, NULL} 263 }; 264 265 void 266 ssh_userauth2(const char *local_user, const char *server_user, char *host, 267 Sensitive *sensitive) 268 { 269 Authctxt authctxt; 270 int type; 271 272 if (options.challenge_response_authentication) 273 options.kbd_interactive_authentication = 1; 274 275 packet_start(SSH2_MSG_SERVICE_REQUEST); 276 packet_put_cstring("ssh-userauth"); 277 packet_send(); 278 debug("SSH2_MSG_SERVICE_REQUEST sent"); 279 packet_write_wait(); 280 type = packet_read(); 281 if (type != SSH2_MSG_SERVICE_ACCEPT) 282 fatal("Server denied authentication request: %d", type); 283 if (packet_remaining() > 0) { 284 char *reply = packet_get_string(NULL); 285 debug2("service_accept: %s", reply); 286 xfree(reply); 287 } else { 288 debug2("buggy server: service_accept w/o service"); 289 } 290 packet_check_eom(); 291 debug("SSH2_MSG_SERVICE_ACCEPT received"); 292 293 if (options.preferred_authentications == NULL) 294 options.preferred_authentications = authmethods_get(); 295 296 /* setup authentication context */ 297 memset(&authctxt, 0, sizeof(authctxt)); 298 pubkey_prepare(&authctxt); 299 authctxt.server_user = server_user; 300 authctxt.local_user = local_user; 301 authctxt.host = host; 302 authctxt.service = "ssh-connection"; /* service name */ 303 authctxt.success = 0; 304 authctxt.method = authmethod_lookup("none"); 305 authctxt.authlist = NULL; 306 authctxt.methoddata = NULL; 307 authctxt.sensitive = sensitive; 308 authctxt.info_req_seen = 0; 309 if (authctxt.method == NULL) 310 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 311 312 /* initial userauth request */ 313 userauth_none(&authctxt); 314 315 dispatch_init(&input_userauth_error); 316 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 317 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 318 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 319 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 320 321 pubkey_cleanup(&authctxt); 322 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 323 324 debug("Authentication succeeded (%s).", authctxt.method->name); 325 } 326 327 void 328 userauth(Authctxt *authctxt, char *authlist) 329 { 330 if (authctxt->methoddata) { 331 xfree(authctxt->methoddata); 332 authctxt->methoddata = NULL; 333 } 334 if (authlist == NULL) { 335 authlist = authctxt->authlist; 336 } else { 337 if (authctxt->authlist) 338 xfree(authctxt->authlist); 339 authctxt->authlist = authlist; 340 } 341 for (;;) { 342 Authmethod *method = authmethod_get(authlist); 343 if (method == NULL) 344 fatal("Permission denied (%s).", authlist); 345 authctxt->method = method; 346 347 /* reset the per method handler */ 348 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 349 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 350 351 /* and try new method */ 352 if (method->userauth(authctxt) != 0) { 353 debug2("we sent a %s packet, wait for reply", method->name); 354 break; 355 } else { 356 debug2("we did not send a packet, disable method"); 357 method->enabled = NULL; 358 } 359 } 360 } 361 362 void 363 input_userauth_error(int type, u_int32_t seq, void *ctxt) 364 { 365 fatal("input_userauth_error: bad message during authentication: " 366 "type %d", type); 367 } 368 369 void 370 input_userauth_banner(int type, u_int32_t seq, void *ctxt) 371 { 372 char *msg, *lang; 373 374 debug3("input_userauth_banner"); 375 msg = packet_get_string(NULL); 376 lang = packet_get_string(NULL); 377 if (options.log_level >= SYSLOG_LEVEL_INFO) 378 fprintf(stderr, "%s", msg); 379 xfree(msg); 380 xfree(lang); 381 } 382 383 void 384 input_userauth_success(int type, u_int32_t seq, void *ctxt) 385 { 386 Authctxt *authctxt = ctxt; 387 if (authctxt == NULL) 388 fatal("input_userauth_success: no authentication context"); 389 if (authctxt->authlist) { 390 xfree(authctxt->authlist); 391 authctxt->authlist = NULL; 392 } 393 if (authctxt->methoddata) { 394 xfree(authctxt->methoddata); 395 authctxt->methoddata = NULL; 396 } 397 authctxt->success = 1; /* break out */ 398 } 399 400 void 401 input_userauth_failure(int type, u_int32_t seq, void *ctxt) 402 { 403 Authctxt *authctxt = ctxt; 404 char *authlist = NULL; 405 int partial; 406 407 if (authctxt == NULL) 408 fatal("input_userauth_failure: no authentication context"); 409 410 authlist = packet_get_string(NULL); 411 partial = packet_get_char(); 412 packet_check_eom(); 413 414 if (partial != 0) 415 logit("Authenticated with partial success."); 416 debug("Authentications that can continue: %s", authlist); 417 418 userauth(authctxt, authlist); 419 } 420 void 421 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 422 { 423 Authctxt *authctxt = ctxt; 424 Key *key = NULL; 425 Identity *id = NULL; 426 Buffer b; 427 int pktype, sent = 0; 428 u_int alen, blen; 429 char *pkalg, *fp; 430 u_char *pkblob; 431 432 if (authctxt == NULL) 433 fatal("input_userauth_pk_ok: no authentication context"); 434 if (datafellows & SSH_BUG_PKOK) { 435 /* this is similar to SSH_BUG_PKAUTH */ 436 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 437 pkblob = packet_get_string(&blen); 438 buffer_init(&b); 439 buffer_append(&b, pkblob, blen); 440 pkalg = buffer_get_string(&b, &alen); 441 buffer_free(&b); 442 } else { 443 pkalg = packet_get_string(&alen); 444 pkblob = packet_get_string(&blen); 445 } 446 packet_check_eom(); 447 448 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 449 450 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 451 debug("unknown pkalg %s", pkalg); 452 goto done; 453 } 454 if ((key = key_from_blob(pkblob, blen)) == NULL) { 455 debug("no key from blob. pkalg %s", pkalg); 456 goto done; 457 } 458 if (key->type != pktype) { 459 error("input_userauth_pk_ok: type mismatch " 460 "for decoded key (received %d, expected %d)", 461 key->type, pktype); 462 goto done; 463 } 464 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 465 debug2("input_userauth_pk_ok: fp %s", fp); 466 xfree(fp); 467 468 /* 469 * search keys in the reverse order, because last candidate has been 470 * moved to the end of the queue. this also avoids confusion by 471 * duplicate keys 472 */ 473 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 474 if (key_equal(key, id->key)) { 475 sent = sign_and_send_pubkey(authctxt, id); 476 break; 477 } 478 } 479 done: 480 if (key != NULL) 481 key_free(key); 482 xfree(pkalg); 483 xfree(pkblob); 484 485 /* try another method if we did not send a packet */ 486 if (sent == 0) 487 userauth(authctxt, NULL); 488 } 489 490 #ifdef GSSAPI 491 int 492 userauth_gssapi(Authctxt *authctxt) 493 { 494 Gssctxt *gssctxt = NULL; 495 static gss_OID_set gss_supported = NULL; 496 static u_int mech = 0; 497 OM_uint32 min; 498 int ok = 0; 499 500 /* Try one GSSAPI method at a time, rather than sending them all at 501 * once. */ 502 503 if (gss_supported == NULL) 504 gss_indicate_mechs(&min, &gss_supported); 505 506 /* Check to see if the mechanism is usable before we offer it */ 507 while (mech < gss_supported->count && !ok) { 508 /* My DER encoding requires length<128 */ 509 if (gss_supported->elements[mech].length < 128 && 510 ssh_gssapi_check_mechanism(&gssctxt, 511 &gss_supported->elements[mech], authctxt->host)) { 512 ok = 1; /* Mechanism works */ 513 } else { 514 mech++; 515 } 516 } 517 518 if (!ok) 519 return 0; 520 521 authctxt->methoddata=(void *)gssctxt; 522 523 packet_start(SSH2_MSG_USERAUTH_REQUEST); 524 packet_put_cstring(authctxt->server_user); 525 packet_put_cstring(authctxt->service); 526 packet_put_cstring(authctxt->method->name); 527 528 packet_put_int(1); 529 530 packet_put_int((gss_supported->elements[mech].length) + 2); 531 packet_put_char(SSH_GSS_OIDTYPE); 532 packet_put_char(gss_supported->elements[mech].length); 533 packet_put_raw(gss_supported->elements[mech].elements, 534 gss_supported->elements[mech].length); 535 536 packet_send(); 537 538 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 539 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 540 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 541 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 542 543 mech++; /* Move along to next candidate */ 544 545 return 1; 546 } 547 548 static OM_uint32 549 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 550 { 551 Authctxt *authctxt = ctxt; 552 Gssctxt *gssctxt = authctxt->methoddata; 553 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 554 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 555 gss_buffer_desc gssbuf; 556 OM_uint32 status, ms, flags; 557 Buffer b; 558 559 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 560 recv_tok, &send_tok, &flags); 561 562 if (send_tok.length > 0) { 563 if (GSS_ERROR(status)) 564 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 565 else 566 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 567 568 packet_put_string(send_tok.value, send_tok.length); 569 packet_send(); 570 gss_release_buffer(&ms, &send_tok); 571 } 572 573 if (status == GSS_S_COMPLETE) { 574 /* send either complete or MIC, depending on mechanism */ 575 if (!(flags & GSS_C_INTEG_FLAG)) { 576 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 577 packet_send(); 578 } else { 579 ssh_gssapi_buildmic(&b, authctxt->server_user, 580 authctxt->service, "gssapi-with-mic"); 581 582 gssbuf.value = buffer_ptr(&b); 583 gssbuf.length = buffer_len(&b); 584 585 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 586 587 if (!GSS_ERROR(status)) { 588 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 589 packet_put_string(mic.value, mic.length); 590 591 packet_send(); 592 } 593 594 buffer_free(&b); 595 gss_release_buffer(&ms, &mic); 596 } 597 } 598 599 return status; 600 } 601 602 void 603 input_gssapi_response(int type, u_int32_t plen, void *ctxt) 604 { 605 Authctxt *authctxt = ctxt; 606 Gssctxt *gssctxt; 607 int oidlen; 608 char *oidv; 609 610 if (authctxt == NULL) 611 fatal("input_gssapi_response: no authentication context"); 612 gssctxt = authctxt->methoddata; 613 614 /* Setup our OID */ 615 oidv = packet_get_string(&oidlen); 616 617 if (oidlen <= 2 || 618 oidv[0] != SSH_GSS_OIDTYPE || 619 oidv[1] != oidlen - 2) { 620 xfree(oidv); 621 debug("Badly encoded mechanism OID received"); 622 userauth(authctxt, NULL); 623 return; 624 } 625 626 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 627 fatal("Server returned different OID than expected"); 628 629 packet_check_eom(); 630 631 xfree(oidv); 632 633 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 634 /* Start again with next method on list */ 635 debug("Trying to start again"); 636 userauth(authctxt, NULL); 637 return; 638 } 639 } 640 641 void 642 input_gssapi_token(int type, u_int32_t plen, void *ctxt) 643 { 644 Authctxt *authctxt = ctxt; 645 gss_buffer_desc recv_tok; 646 OM_uint32 status; 647 u_int slen; 648 649 if (authctxt == NULL) 650 fatal("input_gssapi_response: no authentication context"); 651 652 recv_tok.value = packet_get_string(&slen); 653 recv_tok.length = slen; /* safe typecast */ 654 655 packet_check_eom(); 656 657 status = process_gssapi_token(ctxt, &recv_tok); 658 659 xfree(recv_tok.value); 660 661 if (GSS_ERROR(status)) { 662 /* Start again with the next method in the list */ 663 userauth(authctxt, NULL); 664 return; 665 } 666 } 667 668 void 669 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 670 { 671 Authctxt *authctxt = ctxt; 672 Gssctxt *gssctxt; 673 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 674 gss_buffer_desc recv_tok; 675 OM_uint32 status, ms; 676 u_int len; 677 678 if (authctxt == NULL) 679 fatal("input_gssapi_response: no authentication context"); 680 gssctxt = authctxt->methoddata; 681 682 recv_tok.value = packet_get_string(&len); 683 recv_tok.length = len; 684 685 packet_check_eom(); 686 687 /* Stick it into GSSAPI and see what it says */ 688 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 689 &recv_tok, &send_tok, NULL); 690 691 xfree(recv_tok.value); 692 gss_release_buffer(&ms, &send_tok); 693 694 /* Server will be returning a failed packet after this one */ 695 } 696 697 void 698 input_gssapi_error(int type, u_int32_t plen, void *ctxt) 699 { 700 OM_uint32 maj, min; 701 char *msg; 702 char *lang; 703 704 maj=packet_get_int(); 705 min=packet_get_int(); 706 msg=packet_get_string(NULL); 707 lang=packet_get_string(NULL); 708 709 packet_check_eom(); 710 711 debug("Server GSSAPI Error:\n%s", msg); 712 xfree(msg); 713 xfree(lang); 714 } 715 #endif /* GSSAPI */ 716 717 int 718 userauth_none(Authctxt *authctxt) 719 { 720 /* initial userauth request */ 721 packet_start(SSH2_MSG_USERAUTH_REQUEST); 722 packet_put_cstring(authctxt->server_user); 723 packet_put_cstring(authctxt->service); 724 packet_put_cstring(authctxt->method->name); 725 packet_send(); 726 return 1; 727 } 728 729 int 730 userauth_passwd(Authctxt *authctxt) 731 { 732 static int attempt = 0; 733 char prompt[150]; 734 char *password; 735 736 if (attempt++ >= options.number_of_password_prompts) 737 return 0; 738 739 if (attempt != 1) 740 error("Permission denied, please try again."); 741 742 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 743 authctxt->server_user, authctxt->host); 744 password = read_passphrase(prompt, 0); 745 packet_start(SSH2_MSG_USERAUTH_REQUEST); 746 packet_put_cstring(authctxt->server_user); 747 packet_put_cstring(authctxt->service); 748 packet_put_cstring(authctxt->method->name); 749 packet_put_char(0); 750 packet_put_cstring(password); 751 memset(password, 0, strlen(password)); 752 xfree(password); 753 packet_add_padding(64); 754 packet_send(); 755 756 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 757 &input_userauth_passwd_changereq); 758 759 return 1; 760 } 761 /* 762 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 763 */ 764 void 765 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 766 { 767 Authctxt *authctxt = ctxt; 768 char *info, *lang, *password = NULL, *retype = NULL; 769 char prompt[150]; 770 771 debug2("input_userauth_passwd_changereq"); 772 773 if (authctxt == NULL) 774 fatal("input_userauth_passwd_changereq: " 775 "no authentication context"); 776 777 info = packet_get_string(NULL); 778 lang = packet_get_string(NULL); 779 if (strlen(info) > 0) 780 logit("%s", info); 781 xfree(info); 782 xfree(lang); 783 packet_start(SSH2_MSG_USERAUTH_REQUEST); 784 packet_put_cstring(authctxt->server_user); 785 packet_put_cstring(authctxt->service); 786 packet_put_cstring(authctxt->method->name); 787 packet_put_char(1); /* additional info */ 788 snprintf(prompt, sizeof(prompt), 789 "Enter %.30s@%.128s's old password: ", 790 authctxt->server_user, authctxt->host); 791 password = read_passphrase(prompt, 0); 792 packet_put_cstring(password); 793 memset(password, 0, strlen(password)); 794 xfree(password); 795 password = NULL; 796 while (password == NULL) { 797 snprintf(prompt, sizeof(prompt), 798 "Enter %.30s@%.128s's new password: ", 799 authctxt->server_user, authctxt->host); 800 password = read_passphrase(prompt, RP_ALLOW_EOF); 801 if (password == NULL) { 802 /* bail out */ 803 return; 804 } 805 snprintf(prompt, sizeof(prompt), 806 "Retype %.30s@%.128s's new password: ", 807 authctxt->server_user, authctxt->host); 808 retype = read_passphrase(prompt, 0); 809 if (strcmp(password, retype) != 0) { 810 memset(password, 0, strlen(password)); 811 xfree(password); 812 logit("Mismatch; try again, EOF to quit."); 813 password = NULL; 814 } 815 memset(retype, 0, strlen(retype)); 816 xfree(retype); 817 } 818 packet_put_cstring(password); 819 memset(password, 0, strlen(password)); 820 xfree(password); 821 packet_add_padding(64); 822 packet_send(); 823 824 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 825 &input_userauth_passwd_changereq); 826 } 827 828 static int 829 identity_sign(Identity *id, u_char **sigp, u_int *lenp, 830 u_char *data, u_int datalen) 831 { 832 Key *prv; 833 int ret; 834 835 /* the agent supports this key */ 836 if (id->ac) 837 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 838 data, datalen)); 839 /* 840 * we have already loaded the private key or 841 * the private key is stored in external hardware 842 */ 843 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 844 return (key_sign(id->key, sigp, lenp, data, datalen)); 845 /* load the private key from the file */ 846 if ((prv = load_identity_file(id->filename)) == NULL) 847 return (-1); 848 ret = key_sign(prv, sigp, lenp, data, datalen); 849 key_free(prv); 850 return (ret); 851 } 852 853 static int 854 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 855 { 856 Buffer b; 857 u_char *blob, *signature; 858 u_int bloblen, slen; 859 u_int skip = 0; 860 int ret = -1; 861 int have_sig = 1; 862 863 debug3("sign_and_send_pubkey"); 864 865 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 866 /* we cannot handle this key */ 867 debug3("sign_and_send_pubkey: cannot handle key"); 868 return 0; 869 } 870 /* data to be signed */ 871 buffer_init(&b); 872 if (datafellows & SSH_OLD_SESSIONID) { 873 buffer_append(&b, session_id2, session_id2_len); 874 skip = session_id2_len; 875 } else { 876 buffer_put_string(&b, session_id2, session_id2_len); 877 skip = buffer_len(&b); 878 } 879 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 880 buffer_put_cstring(&b, authctxt->server_user); 881 buffer_put_cstring(&b, 882 datafellows & SSH_BUG_PKSERVICE ? 883 "ssh-userauth" : 884 authctxt->service); 885 if (datafellows & SSH_BUG_PKAUTH) { 886 buffer_put_char(&b, have_sig); 887 } else { 888 buffer_put_cstring(&b, authctxt->method->name); 889 buffer_put_char(&b, have_sig); 890 buffer_put_cstring(&b, key_ssh_name(id->key)); 891 } 892 buffer_put_string(&b, blob, bloblen); 893 894 /* generate signature */ 895 ret = identity_sign(id, &signature, &slen, 896 buffer_ptr(&b), buffer_len(&b)); 897 if (ret == -1) { 898 xfree(blob); 899 buffer_free(&b); 900 return 0; 901 } 902 #ifdef DEBUG_PK 903 buffer_dump(&b); 904 #endif 905 if (datafellows & SSH_BUG_PKSERVICE) { 906 buffer_clear(&b); 907 buffer_append(&b, session_id2, session_id2_len); 908 skip = session_id2_len; 909 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 910 buffer_put_cstring(&b, authctxt->server_user); 911 buffer_put_cstring(&b, authctxt->service); 912 buffer_put_cstring(&b, authctxt->method->name); 913 buffer_put_char(&b, have_sig); 914 if (!(datafellows & SSH_BUG_PKAUTH)) 915 buffer_put_cstring(&b, key_ssh_name(id->key)); 916 buffer_put_string(&b, blob, bloblen); 917 } 918 xfree(blob); 919 920 /* append signature */ 921 buffer_put_string(&b, signature, slen); 922 xfree(signature); 923 924 /* skip session id and packet type */ 925 if (buffer_len(&b) < skip + 1) 926 fatal("userauth_pubkey: internal error"); 927 buffer_consume(&b, skip + 1); 928 929 /* put remaining data from buffer into packet */ 930 packet_start(SSH2_MSG_USERAUTH_REQUEST); 931 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 932 buffer_free(&b); 933 packet_send(); 934 935 return 1; 936 } 937 938 static int 939 send_pubkey_test(Authctxt *authctxt, Identity *id) 940 { 941 u_char *blob; 942 u_int bloblen, have_sig = 0; 943 944 debug3("send_pubkey_test"); 945 946 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 947 /* we cannot handle this key */ 948 debug3("send_pubkey_test: cannot handle key"); 949 return 0; 950 } 951 /* register callback for USERAUTH_PK_OK message */ 952 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 953 954 packet_start(SSH2_MSG_USERAUTH_REQUEST); 955 packet_put_cstring(authctxt->server_user); 956 packet_put_cstring(authctxt->service); 957 packet_put_cstring(authctxt->method->name); 958 packet_put_char(have_sig); 959 if (!(datafellows & SSH_BUG_PKAUTH)) 960 packet_put_cstring(key_ssh_name(id->key)); 961 packet_put_string(blob, bloblen); 962 xfree(blob); 963 packet_send(); 964 return 1; 965 } 966 967 static Key * 968 load_identity_file(char *filename) 969 { 970 Key *private; 971 char prompt[300], *passphrase; 972 int perm_ok, quit, i; 973 struct stat st; 974 975 if (stat(filename, &st) < 0) { 976 debug3("no such identity: %s", filename); 977 return NULL; 978 } 979 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 980 if (!perm_ok) 981 return NULL; 982 if (private == NULL) { 983 if (options.batch_mode) 984 return NULL; 985 snprintf(prompt, sizeof prompt, 986 "Enter passphrase for key '%.100s': ", filename); 987 for (i = 0; i < options.number_of_password_prompts; i++) { 988 passphrase = read_passphrase(prompt, 0); 989 if (strcmp(passphrase, "") != 0) { 990 private = key_load_private_type(KEY_UNSPEC, 991 filename, passphrase, NULL, NULL); 992 quit = 0; 993 } else { 994 debug2("no passphrase given, try next key"); 995 quit = 1; 996 } 997 memset(passphrase, 0, strlen(passphrase)); 998 xfree(passphrase); 999 if (private != NULL || quit) 1000 break; 1001 debug2("bad passphrase given, try again..."); 1002 } 1003 } 1004 return private; 1005 } 1006 1007 /* 1008 * try keys in the following order: 1009 * 1. agent keys that are found in the config file 1010 * 2. other agent keys 1011 * 3. keys that are only listed in the config file 1012 */ 1013 static void 1014 pubkey_prepare(Authctxt *authctxt) 1015 { 1016 Identity *id; 1017 Idlist agent, files, *preferred; 1018 Key *key; 1019 AuthenticationConnection *ac; 1020 char *comment; 1021 int i, found; 1022 1023 TAILQ_INIT(&agent); /* keys from the agent */ 1024 TAILQ_INIT(&files); /* keys from the config file */ 1025 preferred = &authctxt->keys; 1026 TAILQ_INIT(preferred); /* preferred order of keys */ 1027 1028 /* list of keys stored in the filesystem */ 1029 for (i = 0; i < options.num_identity_files; i++) { 1030 key = options.identity_keys[i]; 1031 if (key && key->type == KEY_RSA1) 1032 continue; 1033 options.identity_keys[i] = NULL; 1034 id = xcalloc(1, sizeof(*id)); 1035 id->key = key; 1036 id->filename = xstrdup(options.identity_files[i]); 1037 TAILQ_INSERT_TAIL(&files, id, next); 1038 } 1039 /* list of keys supported by the agent */ 1040 if ((ac = ssh_get_authentication_connection())) { 1041 for (key = ssh_get_first_identity(ac, &comment, 2); 1042 key != NULL; 1043 key = ssh_get_next_identity(ac, &comment, 2)) { 1044 found = 0; 1045 TAILQ_FOREACH(id, &files, next) { 1046 /* agent keys from the config file are preferred */ 1047 if (key_equal(key, id->key)) { 1048 key_free(key); 1049 xfree(comment); 1050 TAILQ_REMOVE(&files, id, next); 1051 TAILQ_INSERT_TAIL(preferred, id, next); 1052 id->ac = ac; 1053 found = 1; 1054 break; 1055 } 1056 } 1057 if (!found && !options.identities_only) { 1058 id = xcalloc(1, sizeof(*id)); 1059 id->key = key; 1060 id->filename = comment; 1061 id->ac = ac; 1062 TAILQ_INSERT_TAIL(&agent, id, next); 1063 } 1064 } 1065 /* append remaining agent keys */ 1066 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1067 TAILQ_REMOVE(&agent, id, next); 1068 TAILQ_INSERT_TAIL(preferred, id, next); 1069 } 1070 authctxt->agent = ac; 1071 } 1072 /* append remaining keys from the config file */ 1073 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1074 TAILQ_REMOVE(&files, id, next); 1075 TAILQ_INSERT_TAIL(preferred, id, next); 1076 } 1077 TAILQ_FOREACH(id, preferred, next) { 1078 debug2("key: %s (%p)", id->filename, id->key); 1079 } 1080 } 1081 1082 static void 1083 pubkey_cleanup(Authctxt *authctxt) 1084 { 1085 Identity *id; 1086 1087 if (authctxt->agent != NULL) 1088 ssh_close_authentication_connection(authctxt->agent); 1089 for (id = TAILQ_FIRST(&authctxt->keys); id; 1090 id = TAILQ_FIRST(&authctxt->keys)) { 1091 TAILQ_REMOVE(&authctxt->keys, id, next); 1092 if (id->key) 1093 key_free(id->key); 1094 if (id->filename) 1095 xfree(id->filename); 1096 xfree(id); 1097 } 1098 } 1099 1100 int 1101 userauth_pubkey(Authctxt *authctxt) 1102 { 1103 Identity *id; 1104 int sent = 0; 1105 1106 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1107 if (id->tried++) 1108 return (0); 1109 /* move key to the end of the queue */ 1110 TAILQ_REMOVE(&authctxt->keys, id, next); 1111 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1112 /* 1113 * send a test message if we have the public key. for 1114 * encrypted keys we cannot do this and have to load the 1115 * private key instead 1116 */ 1117 if (id->key && id->key->type != KEY_RSA1) { 1118 debug("Offering public key: %s", id->filename); 1119 sent = send_pubkey_test(authctxt, id); 1120 } else if (id->key == NULL) { 1121 debug("Trying private key: %s", id->filename); 1122 id->key = load_identity_file(id->filename); 1123 if (id->key != NULL) { 1124 id->isprivate = 1; 1125 sent = sign_and_send_pubkey(authctxt, id); 1126 key_free(id->key); 1127 id->key = NULL; 1128 } 1129 } 1130 if (sent) 1131 return (sent); 1132 } 1133 return (0); 1134 } 1135 1136 /* 1137 * Send userauth request message specifying keyboard-interactive method. 1138 */ 1139 int 1140 userauth_kbdint(Authctxt *authctxt) 1141 { 1142 static int attempt = 0; 1143 1144 if (attempt++ >= options.number_of_password_prompts) 1145 return 0; 1146 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1147 if (attempt > 1 && !authctxt->info_req_seen) { 1148 debug3("userauth_kbdint: disable: no info_req_seen"); 1149 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1150 return 0; 1151 } 1152 1153 debug2("userauth_kbdint"); 1154 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1155 packet_put_cstring(authctxt->server_user); 1156 packet_put_cstring(authctxt->service); 1157 packet_put_cstring(authctxt->method->name); 1158 packet_put_cstring(""); /* lang */ 1159 packet_put_cstring(options.kbd_interactive_devices ? 1160 options.kbd_interactive_devices : ""); 1161 packet_send(); 1162 1163 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1164 return 1; 1165 } 1166 1167 /* 1168 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1169 */ 1170 void 1171 input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1172 { 1173 Authctxt *authctxt = ctxt; 1174 char *name, *inst, *lang, *prompt, *response; 1175 u_int num_prompts, i; 1176 int echo = 0; 1177 1178 debug2("input_userauth_info_req"); 1179 1180 if (authctxt == NULL) 1181 fatal("input_userauth_info_req: no authentication context"); 1182 1183 authctxt->info_req_seen = 1; 1184 1185 name = packet_get_string(NULL); 1186 inst = packet_get_string(NULL); 1187 lang = packet_get_string(NULL); 1188 if (strlen(name) > 0) 1189 logit("%s", name); 1190 if (strlen(inst) > 0) 1191 logit("%s", inst); 1192 xfree(name); 1193 xfree(inst); 1194 xfree(lang); 1195 1196 num_prompts = packet_get_int(); 1197 /* 1198 * Begin to build info response packet based on prompts requested. 1199 * We commit to providing the correct number of responses, so if 1200 * further on we run into a problem that prevents this, we have to 1201 * be sure and clean this up and send a correct error response. 1202 */ 1203 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1204 packet_put_int(num_prompts); 1205 1206 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1207 for (i = 0; i < num_prompts; i++) { 1208 prompt = packet_get_string(NULL); 1209 echo = packet_get_char(); 1210 1211 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1212 1213 packet_put_cstring(response); 1214 memset(response, 0, strlen(response)); 1215 xfree(response); 1216 xfree(prompt); 1217 } 1218 packet_check_eom(); /* done with parsing incoming message. */ 1219 1220 packet_add_padding(64); 1221 packet_send(); 1222 } 1223 1224 static int 1225 ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1226 u_char *data, u_int datalen) 1227 { 1228 Buffer b; 1229 struct stat st; 1230 pid_t pid; 1231 int to[2], from[2], status, version = 2; 1232 1233 debug2("ssh_keysign called"); 1234 1235 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1236 error("ssh_keysign: no installed: %s", strerror(errno)); 1237 return -1; 1238 } 1239 if (fflush(stdout) != 0) 1240 error("ssh_keysign: fflush: %s", strerror(errno)); 1241 if (pipe(to) < 0) { 1242 error("ssh_keysign: pipe: %s", strerror(errno)); 1243 return -1; 1244 } 1245 if (pipe(from) < 0) { 1246 error("ssh_keysign: pipe: %s", strerror(errno)); 1247 return -1; 1248 } 1249 if ((pid = fork()) < 0) { 1250 error("ssh_keysign: fork: %s", strerror(errno)); 1251 return -1; 1252 } 1253 if (pid == 0) { 1254 permanently_drop_suid(getuid()); 1255 close(from[0]); 1256 if (dup2(from[1], STDOUT_FILENO) < 0) 1257 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1258 close(to[1]); 1259 if (dup2(to[0], STDIN_FILENO) < 0) 1260 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1261 close(from[1]); 1262 close(to[0]); 1263 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1264 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1265 strerror(errno)); 1266 } 1267 close(from[1]); 1268 close(to[0]); 1269 1270 buffer_init(&b); 1271 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1272 buffer_put_string(&b, data, datalen); 1273 if (ssh_msg_send(to[1], version, &b) == -1) 1274 fatal("ssh_keysign: couldn't send request"); 1275 1276 if (ssh_msg_recv(from[0], &b) < 0) { 1277 error("ssh_keysign: no reply"); 1278 buffer_free(&b); 1279 return -1; 1280 } 1281 close(from[0]); 1282 close(to[1]); 1283 1284 while (waitpid(pid, &status, 0) < 0) 1285 if (errno != EINTR) 1286 break; 1287 1288 if (buffer_get_char(&b) != version) { 1289 error("ssh_keysign: bad version"); 1290 buffer_free(&b); 1291 return -1; 1292 } 1293 *sigp = buffer_get_string(&b, lenp); 1294 buffer_free(&b); 1295 1296 return 0; 1297 } 1298 1299 int 1300 userauth_hostbased(Authctxt *authctxt) 1301 { 1302 Key *private = NULL; 1303 Sensitive *sensitive = authctxt->sensitive; 1304 Buffer b; 1305 u_char *signature, *blob; 1306 char *chost, *pkalg, *p; 1307 const char *service; 1308 u_int blen, slen; 1309 int ok, i, len, found = 0; 1310 1311 /* check for a useful key */ 1312 for (i = 0; i < sensitive->nkeys; i++) { 1313 private = sensitive->keys[i]; 1314 if (private && private->type != KEY_RSA1) { 1315 found = 1; 1316 /* we take and free the key */ 1317 sensitive->keys[i] = NULL; 1318 break; 1319 } 1320 } 1321 if (!found) { 1322 debug("No more client hostkeys for hostbased authentication."); 1323 return 0; 1324 } 1325 if (key_to_blob(private, &blob, &blen) == 0) { 1326 key_free(private); 1327 return 0; 1328 } 1329 /* figure out a name for the client host */ 1330 p = get_local_name(packet_get_connection_in()); 1331 if (p == NULL) { 1332 error("userauth_hostbased: cannot get local ipaddr/name"); 1333 key_free(private); 1334 xfree(blob); 1335 return 0; 1336 } 1337 len = strlen(p) + 2; 1338 xasprintf(&chost, "%s.", p); 1339 debug2("userauth_hostbased: chost %s", chost); 1340 xfree(p); 1341 1342 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1343 authctxt->service; 1344 pkalg = xstrdup(key_ssh_name(private)); 1345 buffer_init(&b); 1346 /* construct data */ 1347 buffer_put_string(&b, session_id2, session_id2_len); 1348 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1349 buffer_put_cstring(&b, authctxt->server_user); 1350 buffer_put_cstring(&b, service); 1351 buffer_put_cstring(&b, authctxt->method->name); 1352 buffer_put_cstring(&b, pkalg); 1353 buffer_put_string(&b, blob, blen); 1354 buffer_put_cstring(&b, chost); 1355 buffer_put_cstring(&b, authctxt->local_user); 1356 #ifdef DEBUG_PK 1357 buffer_dump(&b); 1358 #endif 1359 if (sensitive->external_keysign) 1360 ok = ssh_keysign(private, &signature, &slen, 1361 buffer_ptr(&b), buffer_len(&b)); 1362 else 1363 ok = key_sign(private, &signature, &slen, 1364 buffer_ptr(&b), buffer_len(&b)); 1365 key_free(private); 1366 buffer_free(&b); 1367 if (ok != 0) { 1368 error("key_sign failed"); 1369 xfree(chost); 1370 xfree(pkalg); 1371 xfree(blob); 1372 return 0; 1373 } 1374 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1375 packet_put_cstring(authctxt->server_user); 1376 packet_put_cstring(authctxt->service); 1377 packet_put_cstring(authctxt->method->name); 1378 packet_put_cstring(pkalg); 1379 packet_put_string(blob, blen); 1380 packet_put_cstring(chost); 1381 packet_put_cstring(authctxt->local_user); 1382 packet_put_string(signature, slen); 1383 memset(signature, 's', slen); 1384 xfree(signature); 1385 xfree(chost); 1386 xfree(pkalg); 1387 xfree(blob); 1388 1389 packet_send(); 1390 return 1; 1391 } 1392 1393 /* find auth method */ 1394 1395 /* 1396 * given auth method name, if configurable options permit this method fill 1397 * in auth_ident field and return true, otherwise return false. 1398 */ 1399 static int 1400 authmethod_is_enabled(Authmethod *method) 1401 { 1402 if (method == NULL) 1403 return 0; 1404 /* return false if options indicate this method is disabled */ 1405 if (method->enabled == NULL || *method->enabled == 0) 1406 return 0; 1407 /* return false if batch mode is enabled but method needs interactive mode */ 1408 if (method->batch_flag != NULL && *method->batch_flag != 0) 1409 return 0; 1410 return 1; 1411 } 1412 1413 static Authmethod * 1414 authmethod_lookup(const char *name) 1415 { 1416 Authmethod *method = NULL; 1417 if (name != NULL) 1418 for (method = authmethods; method->name != NULL; method++) 1419 if (strcmp(name, method->name) == 0) 1420 return method; 1421 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1422 return NULL; 1423 } 1424 1425 /* XXX internal state */ 1426 static Authmethod *current = NULL; 1427 static char *supported = NULL; 1428 static char *preferred = NULL; 1429 1430 /* 1431 * Given the authentication method list sent by the server, return the 1432 * next method we should try. If the server initially sends a nil list, 1433 * use a built-in default list. 1434 */ 1435 static Authmethod * 1436 authmethod_get(char *authlist) 1437 { 1438 char *name = NULL; 1439 u_int next; 1440 1441 /* Use a suitable default if we're passed a nil list. */ 1442 if (authlist == NULL || strlen(authlist) == 0) 1443 authlist = options.preferred_authentications; 1444 1445 if (supported == NULL || strcmp(authlist, supported) != 0) { 1446 debug3("start over, passed a different list %s", authlist); 1447 if (supported != NULL) 1448 xfree(supported); 1449 supported = xstrdup(authlist); 1450 preferred = options.preferred_authentications; 1451 debug3("preferred %s", preferred); 1452 current = NULL; 1453 } else if (current != NULL && authmethod_is_enabled(current)) 1454 return current; 1455 1456 for (;;) { 1457 if ((name = match_list(preferred, supported, &next)) == NULL) { 1458 debug("No more authentication methods to try."); 1459 current = NULL; 1460 return NULL; 1461 } 1462 preferred += next; 1463 debug3("authmethod_lookup %s", name); 1464 debug3("remaining preferred: %s", preferred); 1465 if ((current = authmethod_lookup(name)) != NULL && 1466 authmethod_is_enabled(current)) { 1467 debug3("authmethod_is_enabled %s", name); 1468 debug("Next authentication method: %s", name); 1469 return current; 1470 } 1471 } 1472 } 1473 1474 static char * 1475 authmethods_get(void) 1476 { 1477 Authmethod *method = NULL; 1478 Buffer b; 1479 char *list; 1480 1481 buffer_init(&b); 1482 for (method = authmethods; method->name != NULL; method++) { 1483 if (authmethod_is_enabled(method)) { 1484 if (buffer_len(&b) > 0) 1485 buffer_append(&b, ",", 1); 1486 buffer_append(&b, method->name, strlen(method->name)); 1487 } 1488 } 1489 buffer_append(&b, "\0", 1); 1490 list = xstrdup(buffer_ptr(&b)); 1491 buffer_free(&b); 1492 return list; 1493 } 1494