1 /* $NetBSD: sshconnect2.c,v 1.26 2016/08/02 13:45:12 christos Exp $ */ 2 /* $OpenBSD: sshconnect2.c,v 1.247 2016/07/22 05:46:11 dtucker Exp $ */ 3 /* 4 * Copyright (c) 2000 Markus Friedl. All rights reserved. 5 * Copyright (c) 2008 Damien Miller. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 __RCSID("$NetBSD: sshconnect2.c,v 1.26 2016/08/02 13:45:12 christos Exp $"); 30 #include <sys/types.h> 31 #include <sys/socket.h> 32 #include <sys/wait.h> 33 #include <sys/queue.h> 34 #include <sys/stat.h> 35 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <netdb.h> 39 #include <stdio.h> 40 #include <string.h> 41 #include <signal.h> 42 #include <pwd.h> 43 #include <unistd.h> 44 #include <vis.h> 45 46 #ifdef KRB5 47 #include <krb5.h> 48 #endif 49 50 #include "xmalloc.h" 51 #include "ssh.h" 52 #include "ssh2.h" 53 #include "buffer.h" 54 #include "packet.h" 55 #include "compat.h" 56 #include "cipher.h" 57 #include "key.h" 58 #include "kex.h" 59 #include "myproposal.h" 60 #include "sshconnect.h" 61 #include "authfile.h" 62 #include "dh.h" 63 #include "authfd.h" 64 #include "log.h" 65 #include "misc.h" 66 #include "readconf.h" 67 #include "match.h" 68 #include "dispatch.h" 69 #include "canohost.h" 70 #include "msg.h" 71 #include "pathnames.h" 72 #include "uidswap.h" 73 #include "hostfile.h" 74 #include "ssherr.h" 75 #include "utf8.h" 76 /* XXX */ 77 const char *auth_get_canonical_hostname(struct ssh *, int); 78 79 #ifdef GSSAPI 80 #include "ssh-gss.h" 81 #endif 82 83 /* import */ 84 extern char *client_version_string; 85 extern char *server_version_string; 86 extern Options options; 87 88 /* tty_flag is set in ssh.c. use this in ssh_userauth2 */ 89 /* if it is set then prevent the switch to the null cipher */ 90 91 extern int tty_flag; 92 93 /* 94 * SSH2 key exchange 95 */ 96 97 u_char *session_id2 = NULL; 98 u_int session_id2_len = 0; 99 100 char *xxx_host; 101 struct sockaddr *xxx_hostaddr; 102 103 static int 104 verify_host_key_callback(Key *hostkey, struct ssh *ssh) 105 { 106 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 107 fatal("Host key verification failed."); 108 return 0; 109 } 110 111 static char * 112 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 113 { 114 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 115 size_t maxlen; 116 struct hostkeys *hostkeys; 117 int ktype; 118 u_int i; 119 120 /* Find all hostkeys for this hostname */ 121 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 122 hostkeys = init_hostkeys(); 123 for (i = 0; i < options.num_user_hostfiles; i++) 124 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 125 for (i = 0; i < options.num_system_hostfiles; i++) 126 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 127 128 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 129 maxlen = strlen(avail) + 1; 130 first = xmalloc(maxlen); 131 last = xmalloc(maxlen); 132 *first = *last = '\0'; 133 134 #define ALG_APPEND(to, from) \ 135 do { \ 136 if (*to != '\0') \ 137 strlcat(to, ",", maxlen); \ 138 strlcat(to, from, maxlen); \ 139 } while (0) 140 141 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 142 if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC) 143 fatal("%s: unknown alg %s", __func__, alg); 144 if (lookup_key_in_hostkeys_by_type(hostkeys, 145 sshkey_type_plain(ktype), NULL)) 146 ALG_APPEND(first, alg); 147 else 148 ALG_APPEND(last, alg); 149 } 150 #undef ALG_APPEND 151 xasprintf(&ret, "%s%s%s", first, 152 (*first == '\0' || *last == '\0') ? "" : ",", last); 153 if (*first != '\0') 154 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 155 156 free(first); 157 free(last); 158 free(hostname); 159 free(oavail); 160 free_hostkeys(hostkeys); 161 162 return ret; 163 } 164 165 void 166 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 167 { 168 const char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; 169 char *s; 170 struct kex *kex; 171 int r; 172 173 xxx_host = host; 174 xxx_hostaddr = hostaddr; 175 176 if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL) 177 fatal("%s: kex_names_cat", __func__); 178 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s); 179 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 180 compat_cipher_proposal(options.ciphers); 181 myproposal[PROPOSAL_ENC_ALGS_STOC] = 182 compat_cipher_proposal(options.ciphers); 183 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 184 myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ? 185 "zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib"; 186 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 187 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 188 if (options.hostkeyalgorithms != NULL) { 189 if (kex_assemble_names(KEX_DEFAULT_PK_ALG, 190 &options.hostkeyalgorithms) != 0) 191 fatal("%s: kex_assemble_namelist", __func__); 192 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 193 compat_pkalg_proposal(options.hostkeyalgorithms); 194 } else { 195 /* Enforce default */ 196 options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG); 197 /* Prefer algorithms that we already have keys for */ 198 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 199 compat_pkalg_proposal( 200 order_hostkeyalgs(host, hostaddr, port)); 201 } 202 203 if (options.rekey_limit || options.rekey_interval) 204 packet_set_rekey_limits((u_int32_t)options.rekey_limit, 205 (time_t)options.rekey_interval); 206 207 /* start key exchange */ 208 if ((r = kex_setup(active_state, myproposal)) != 0) 209 fatal("kex_setup: %s", ssh_err(r)); 210 kex = active_state->kex; 211 #ifdef WITH_OPENSSL 212 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 213 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 214 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client; 215 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client; 216 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client; 217 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 218 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 219 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 220 #endif 221 kex->kex[KEX_C25519_SHA256] = kexc25519_client; 222 kex->client_version_string=client_version_string; 223 kex->server_version_string=server_version_string; 224 kex->verify_host_key=&verify_host_key_callback; 225 226 dispatch_run(DISPATCH_BLOCK, &kex->done, active_state); 227 228 /* remove ext-info from the KEX proposals for rekeying */ 229 myproposal[PROPOSAL_KEX_ALGS] = 230 compat_kex_proposal(options.kex_algorithms); 231 if ((r = kex_prop2buf(kex->my, myproposal)) != 0) 232 fatal("kex_prop2buf: %s", ssh_err(r)); 233 234 session_id2 = kex->session_id; 235 session_id2_len = kex->session_id_len; 236 237 #ifdef DEBUG_KEXDH 238 /* send 1st encrypted/maced/compressed message */ 239 packet_start(SSH2_MSG_IGNORE); 240 packet_put_cstring("markus"); 241 packet_send(); 242 packet_write_wait(); 243 #endif 244 } 245 246 /* 247 * Authenticate user 248 */ 249 250 typedef struct cauthctxt Authctxt; 251 typedef struct cauthmethod Authmethod; 252 typedef struct identity Identity; 253 typedef struct idlist Idlist; 254 255 struct identity { 256 TAILQ_ENTRY(identity) next; 257 int agent_fd; /* >=0 if agent supports key */ 258 struct sshkey *key; /* public/private key */ 259 char *filename; /* comment for agent-only keys */ 260 int tried; 261 int isprivate; /* key points to the private key */ 262 int userprovided; 263 }; 264 TAILQ_HEAD(idlist, identity); 265 266 struct cauthctxt { 267 const char *server_user; 268 const char *local_user; 269 const char *host; 270 const char *service; 271 struct cauthmethod *method; 272 sig_atomic_t success; 273 char *authlist; 274 int attempt; 275 /* pubkey */ 276 struct idlist keys; 277 int agent_fd; 278 /* hostbased */ 279 Sensitive *sensitive; 280 char *oktypes, *ktypes; 281 const char *active_ktype; 282 /* kbd-interactive */ 283 int info_req_seen; 284 /* generic */ 285 void *methoddata; 286 }; 287 288 struct cauthmethod { 289 const char *name; /* string to compare against server's list */ 290 int (*userauth)(Authctxt *authctxt); 291 void (*cleanup)(Authctxt *authctxt); 292 int *enabled; /* flag in option struct that enables method */ 293 int *batch_flag; /* flag in option struct that disables method */ 294 }; 295 296 int input_userauth_service_accept(int, u_int32_t, void *); 297 int input_userauth_ext_info(int, u_int32_t, void *); 298 int input_userauth_success(int, u_int32_t, void *); 299 int input_userauth_success_unexpected(int, u_int32_t, void *); 300 int input_userauth_failure(int, u_int32_t, void *); 301 int input_userauth_banner(int, u_int32_t, void *); 302 int input_userauth_error(int, u_int32_t, void *); 303 int input_userauth_info_req(int, u_int32_t, void *); 304 int input_userauth_pk_ok(int, u_int32_t, void *); 305 int input_userauth_passwd_changereq(int, u_int32_t, void *); 306 307 int userauth_none(Authctxt *); 308 int userauth_pubkey(Authctxt *); 309 int userauth_passwd(Authctxt *); 310 int userauth_kbdint(Authctxt *); 311 int userauth_hostbased(Authctxt *); 312 int userauth_kerberos(Authctxt *); 313 314 #ifdef GSSAPI 315 int userauth_gssapi(Authctxt *authctxt); 316 int input_gssapi_response(int type, u_int32_t, void *); 317 int input_gssapi_token(int type, u_int32_t, void *); 318 int input_gssapi_hash(int type, u_int32_t, void *); 319 int input_gssapi_error(int, u_int32_t, void *); 320 int input_gssapi_errtok(int, u_int32_t, void *); 321 #endif 322 323 void userauth(Authctxt *, char *); 324 325 static int sign_and_send_pubkey(Authctxt *, Identity *); 326 static void pubkey_prepare(Authctxt *); 327 static void pubkey_cleanup(Authctxt *); 328 static Key *load_identity_file(Identity *); 329 330 static Authmethod *authmethod_get(char *authlist); 331 static Authmethod *authmethod_lookup(const char *name); 332 static char *authmethods_get(void); 333 334 Authmethod authmethods[] = { 335 #ifdef GSSAPI 336 {"gssapi-with-mic", 337 userauth_gssapi, 338 NULL, 339 &options.gss_authentication, 340 NULL}, 341 #endif 342 {"hostbased", 343 userauth_hostbased, 344 NULL, 345 &options.hostbased_authentication, 346 NULL}, 347 #if KRB5 348 {"kerberos-2@ssh.com", 349 userauth_kerberos, 350 NULL, 351 &options.kerberos_authentication, 352 NULL}, 353 #endif 354 {"publickey", 355 userauth_pubkey, 356 NULL, 357 &options.pubkey_authentication, 358 NULL}, 359 {"keyboard-interactive", 360 userauth_kbdint, 361 NULL, 362 &options.kbd_interactive_authentication, 363 &options.batch_mode}, 364 {"password", 365 userauth_passwd, 366 NULL, 367 &options.password_authentication, 368 &options.batch_mode}, 369 {"none", 370 userauth_none, 371 NULL, 372 NULL, 373 NULL}, 374 {NULL, NULL, NULL, NULL, NULL} 375 }; 376 377 void 378 ssh_userauth2(const char *local_user, const char *server_user, char *host, 379 Sensitive *sensitive) 380 { 381 struct ssh *ssh = active_state; 382 Authctxt authctxt; 383 int r; 384 385 if (options.challenge_response_authentication) 386 options.kbd_interactive_authentication = 1; 387 if (options.preferred_authentications == NULL) 388 options.preferred_authentications = authmethods_get(); 389 390 /* setup authentication context */ 391 memset(&authctxt, 0, sizeof(authctxt)); 392 pubkey_prepare(&authctxt); 393 authctxt.server_user = server_user; 394 authctxt.local_user = local_user; 395 authctxt.host = host; 396 authctxt.service = "ssh-connection"; /* service name */ 397 authctxt.success = 0; 398 authctxt.method = authmethod_lookup("none"); 399 authctxt.authlist = NULL; 400 authctxt.methoddata = NULL; 401 authctxt.sensitive = sensitive; 402 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 403 authctxt.info_req_seen = 0; 404 authctxt.agent_fd = -1; 405 if (authctxt.method == NULL) 406 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 407 408 if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 || 409 (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 || 410 (r = sshpkt_send(ssh)) != 0) 411 fatal("%s: %s", __func__, ssh_err(r)); 412 413 ssh_dispatch_init(ssh, &input_userauth_error); 414 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info); 415 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept); 416 ssh_dispatch_run(ssh, DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 417 418 pubkey_cleanup(&authctxt); 419 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 420 421 /* if the user wants to use the none cipher do it */ 422 /* post authentication and only if the right conditions are met */ 423 /* both of the NONE commands must be true and there must be no */ 424 /* tty allocated */ 425 if ((options.none_switch == 1) && (options.none_enabled == 1)) 426 { 427 if (tty_flag) /* no null on tty sessions */ 428 { 429 /* requested NONE cipher when in a tty */ 430 debug("Cannot switch to NONE cipher with tty allocated"); 431 fprintf(stderr, "NONE cipher switch disabled when a TTY is allocated\n"); 432 } 433 } 434 debug("Authentication succeeded (%s).", authctxt.method->name); 435 } 436 437 /* ARGSUSED */ 438 int 439 input_userauth_service_accept(int type, u_int32_t seqnr, void *ctxt) 440 { 441 Authctxt *authctxt = ctxt; 442 struct ssh *ssh = active_state; 443 int r; 444 445 if (ssh_packet_remaining(ssh) > 0) { 446 char *reply; 447 448 if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0) 449 goto out; 450 debug2("service_accept: %s", reply); 451 free(reply); 452 } else { 453 debug2("buggy server: service_accept w/o service"); 454 } 455 if ((r = sshpkt_get_end(ssh)) != 0) 456 goto out; 457 debug("SSH2_MSG_SERVICE_ACCEPT received"); 458 459 /* initial userauth request */ 460 userauth_none(authctxt); 461 462 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error); 463 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 464 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 465 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 466 r = 0; 467 out: 468 return r; 469 } 470 471 /* ARGSUSED */ 472 int 473 input_userauth_ext_info(int type, u_int32_t seqnr, void *ctxt) 474 { 475 return kex_input_ext_info(type, seqnr, active_state); 476 } 477 478 void 479 userauth(Authctxt *authctxt, char *authlist) 480 { 481 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 482 authctxt->method->cleanup(authctxt); 483 484 free(authctxt->methoddata); 485 authctxt->methoddata = NULL; 486 if (authlist == NULL) { 487 authlist = authctxt->authlist; 488 } else { 489 free(authctxt->authlist); 490 authctxt->authlist = authlist; 491 } 492 for (;;) { 493 Authmethod *method = authmethod_get(authlist); 494 if (method == NULL) 495 fatal("Permission denied (%s).", authlist); 496 authctxt->method = method; 497 498 /* reset the per method handler */ 499 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 500 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 501 502 /* and try new method */ 503 if (method->userauth(authctxt) != 0) { 504 debug2("we sent a %s packet, wait for reply", method->name); 505 break; 506 } else { 507 debug2("we did not send a packet, disable method"); 508 method->enabled = NULL; 509 } 510 } 511 } 512 513 /* ARGSUSED */ 514 int 515 input_userauth_error(int type, u_int32_t seq, void *ctxt) 516 { 517 fatal("input_userauth_error: bad message during authentication: " 518 "type %d", type); 519 return 0; 520 } 521 522 /* ARGSUSED */ 523 int 524 input_userauth_banner(int type, u_int32_t seq, void *ctxt) 525 { 526 char *msg, *lang; 527 u_int len; 528 529 debug3("%s", __func__); 530 msg = packet_get_string(&len); 531 lang = packet_get_string(NULL); 532 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) 533 fmprintf(stderr, "%s", msg); 534 free(msg); 535 free(lang); 536 return 0; 537 } 538 539 /* ARGSUSED */ 540 int 541 input_userauth_success(int type, u_int32_t seq, void *ctxt) 542 { 543 Authctxt *authctxt = ctxt; 544 545 if (authctxt == NULL) 546 fatal("input_userauth_success: no authentication context"); 547 free(authctxt->authlist); 548 authctxt->authlist = NULL; 549 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 550 authctxt->method->cleanup(authctxt); 551 free(authctxt->methoddata); 552 authctxt->methoddata = NULL; 553 authctxt->success = 1; /* break out */ 554 return 0; 555 } 556 557 int 558 input_userauth_success_unexpected(int type, u_int32_t seq, void *ctxt) 559 { 560 Authctxt *authctxt = ctxt; 561 562 if (authctxt == NULL) 563 fatal("%s: no authentication context", __func__); 564 565 fatal("Unexpected authentication success during %s.", 566 authctxt->method->name); 567 return 0; 568 } 569 570 /* ARGSUSED */ 571 int 572 input_userauth_failure(int type, u_int32_t seq, void *ctxt) 573 { 574 Authctxt *authctxt = ctxt; 575 char *authlist = NULL; 576 int partial; 577 578 if (authctxt == NULL) 579 fatal("input_userauth_failure: no authentication context"); 580 581 authlist = packet_get_string(NULL); 582 partial = packet_get_char(); 583 packet_check_eom(); 584 585 if (partial != 0) { 586 verbose("Authenticated with partial success."); 587 /* reset state */ 588 pubkey_cleanup(authctxt); 589 pubkey_prepare(authctxt); 590 } 591 debug("Authentications that can continue: %s", authlist); 592 593 userauth(authctxt, authlist); 594 return 0; 595 } 596 597 /* ARGSUSED */ 598 int 599 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 600 { 601 Authctxt *authctxt = ctxt; 602 Key *key = NULL; 603 Identity *id = NULL; 604 Buffer b; 605 int pktype, sent = 0; 606 u_int alen, blen; 607 char *pkalg, *fp; 608 u_char *pkblob; 609 610 if (authctxt == NULL) 611 fatal("input_userauth_pk_ok: no authentication context"); 612 if (datafellows & SSH_BUG_PKOK) { 613 /* this is similar to SSH_BUG_PKAUTH */ 614 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 615 pkblob = packet_get_string(&blen); 616 buffer_init(&b); 617 buffer_append(&b, pkblob, blen); 618 pkalg = buffer_get_string(&b, &alen); 619 buffer_free(&b); 620 } else { 621 pkalg = packet_get_string(&alen); 622 pkblob = packet_get_string(&blen); 623 } 624 packet_check_eom(); 625 626 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 627 628 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 629 debug("unknown pkalg %s", pkalg); 630 goto done; 631 } 632 if ((key = key_from_blob(pkblob, blen)) == NULL) { 633 debug("no key from blob. pkalg %s", pkalg); 634 goto done; 635 } 636 if (key->type != pktype) { 637 error("input_userauth_pk_ok: type mismatch " 638 "for decoded key (received %d, expected %d)", 639 key->type, pktype); 640 goto done; 641 } 642 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 643 SSH_FP_DEFAULT)) == NULL) 644 goto done; 645 debug2("input_userauth_pk_ok: fp %s", fp); 646 free(fp); 647 648 /* 649 * search keys in the reverse order, because last candidate has been 650 * moved to the end of the queue. this also avoids confusion by 651 * duplicate keys 652 */ 653 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 654 if (key_equal(key, id->key)) { 655 sent = sign_and_send_pubkey(authctxt, id); 656 break; 657 } 658 } 659 done: 660 if (key != NULL) 661 key_free(key); 662 free(pkalg); 663 free(pkblob); 664 665 /* try another method if we did not send a packet */ 666 if (sent == 0) 667 userauth(authctxt, NULL); 668 return 0; 669 } 670 671 #ifdef GSSAPI 672 int 673 userauth_gssapi(Authctxt *authctxt) 674 { 675 Gssctxt *gssctxt = NULL; 676 static gss_OID_set gss_supported = NULL; 677 static u_int mech = 0; 678 OM_uint32 min; 679 int ok = 0; 680 681 /* Try one GSSAPI method at a time, rather than sending them all at 682 * once. */ 683 684 if (gss_supported == NULL) 685 gss_indicate_mechs(&min, &gss_supported); 686 687 /* Check to see if the mechanism is usable before we offer it */ 688 while (mech < gss_supported->count && !ok) { 689 /* My DER encoding requires length<128 */ 690 if (gss_supported->elements[mech].length < 128 && 691 ssh_gssapi_check_mechanism(&gssctxt, 692 &gss_supported->elements[mech], authctxt->host)) { 693 ok = 1; /* Mechanism works */ 694 } else { 695 mech++; 696 } 697 } 698 699 if (!ok) { 700 ssh_gssapi_delete_ctx(&gssctxt); 701 return 0; 702 } 703 704 authctxt->methoddata=(void *)gssctxt; 705 706 packet_start(SSH2_MSG_USERAUTH_REQUEST); 707 packet_put_cstring(authctxt->server_user); 708 packet_put_cstring(authctxt->service); 709 packet_put_cstring(authctxt->method->name); 710 711 packet_put_int(1); 712 713 packet_put_int((gss_supported->elements[mech].length) + 2); 714 packet_put_char(SSH_GSS_OIDTYPE); 715 packet_put_char(gss_supported->elements[mech].length); 716 packet_put_raw(gss_supported->elements[mech].elements, 717 gss_supported->elements[mech].length); 718 719 packet_send(); 720 721 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 722 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 723 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 724 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 725 726 mech++; /* Move along to next candidate */ 727 728 return 1; 729 } 730 731 static OM_uint32 732 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 733 { 734 Authctxt *authctxt = ctxt; 735 Gssctxt *gssctxt = authctxt->methoddata; 736 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 737 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 738 gss_buffer_desc gssbuf; 739 OM_uint32 status, ms, flags; 740 Buffer b; 741 742 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 743 recv_tok, &send_tok, &flags); 744 745 if (send_tok.length > 0) { 746 if (GSS_ERROR(status)) 747 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 748 else 749 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 750 751 packet_put_string(send_tok.value, send_tok.length); 752 packet_send(); 753 gss_release_buffer(&ms, &send_tok); 754 } 755 756 if (status == GSS_S_COMPLETE) { 757 /* send either complete or MIC, depending on mechanism */ 758 if (!(flags & GSS_C_INTEG_FLAG)) { 759 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 760 packet_send(); 761 } else { 762 ssh_gssapi_buildmic(&b, authctxt->server_user, 763 authctxt->service, "gssapi-with-mic"); 764 765 gssbuf.value = buffer_ptr(&b); 766 gssbuf.length = buffer_len(&b); 767 768 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 769 770 if (!GSS_ERROR(status)) { 771 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 772 packet_put_string(mic.value, mic.length); 773 774 packet_send(); 775 } 776 777 buffer_free(&b); 778 gss_release_buffer(&ms, &mic); 779 } 780 } 781 782 return status; 783 } 784 785 /* ARGSUSED */ 786 int 787 input_gssapi_response(int type, u_int32_t plen, void *ctxt) 788 { 789 Authctxt *authctxt = ctxt; 790 Gssctxt *gssctxt; 791 int oidlen; 792 char *oidv; 793 794 if (authctxt == NULL) 795 fatal("input_gssapi_response: no authentication context"); 796 gssctxt = authctxt->methoddata; 797 798 /* Setup our OID */ 799 oidv = packet_get_string(&oidlen); 800 801 if (oidlen <= 2 || 802 oidv[0] != SSH_GSS_OIDTYPE || 803 oidv[1] != oidlen - 2) { 804 free(oidv); 805 debug("Badly encoded mechanism OID received"); 806 userauth(authctxt, NULL); 807 return 0; 808 } 809 810 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 811 fatal("Server returned different OID than expected"); 812 813 packet_check_eom(); 814 815 free(oidv); 816 817 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 818 /* Start again with next method on list */ 819 debug("Trying to start again"); 820 userauth(authctxt, NULL); 821 return 0; 822 } 823 return 0; 824 } 825 826 /* ARGSUSED */ 827 int 828 input_gssapi_token(int type, u_int32_t plen, void *ctxt) 829 { 830 Authctxt *authctxt = ctxt; 831 gss_buffer_desc recv_tok; 832 OM_uint32 status; 833 u_int slen; 834 835 if (authctxt == NULL) 836 fatal("input_gssapi_response: no authentication context"); 837 838 recv_tok.value = packet_get_string(&slen); 839 recv_tok.length = slen; /* safe typecast */ 840 841 packet_check_eom(); 842 843 status = process_gssapi_token(ctxt, &recv_tok); 844 845 free(recv_tok.value); 846 847 if (GSS_ERROR(status)) { 848 /* Start again with the next method in the list */ 849 userauth(authctxt, NULL); 850 return 0; 851 } 852 return 0; 853 } 854 855 /* ARGSUSED */ 856 int 857 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 858 { 859 Authctxt *authctxt = ctxt; 860 Gssctxt *gssctxt; 861 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 862 gss_buffer_desc recv_tok; 863 OM_uint32 ms; 864 u_int len; 865 866 if (authctxt == NULL) 867 fatal("input_gssapi_response: no authentication context"); 868 gssctxt = authctxt->methoddata; 869 870 recv_tok.value = packet_get_string(&len); 871 recv_tok.length = len; 872 873 packet_check_eom(); 874 875 /* Stick it into GSSAPI and see what it says */ 876 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 877 &recv_tok, &send_tok, NULL); 878 879 free(recv_tok.value); 880 gss_release_buffer(&ms, &send_tok); 881 882 /* Server will be returning a failed packet after this one */ 883 return 0; 884 } 885 886 /* ARGSUSED */ 887 int 888 input_gssapi_error(int type, u_int32_t plen, void *ctxt) 889 { 890 char *msg; 891 char *lang; 892 893 /* maj */(void)packet_get_int(); 894 /* min */(void)packet_get_int(); 895 msg=packet_get_string(NULL); 896 lang=packet_get_string(NULL); 897 898 packet_check_eom(); 899 900 debug("Server GSSAPI Error:\n%s", msg); 901 free(msg); 902 free(lang); 903 return 0; 904 } 905 #endif /* GSSAPI */ 906 907 int 908 userauth_none(Authctxt *authctxt) 909 { 910 /* initial userauth request */ 911 packet_start(SSH2_MSG_USERAUTH_REQUEST); 912 packet_put_cstring(authctxt->server_user); 913 packet_put_cstring(authctxt->service); 914 packet_put_cstring(authctxt->method->name); 915 packet_send(); 916 return 1; 917 } 918 919 int 920 userauth_passwd(Authctxt *authctxt) 921 { 922 static int attempt = 0; 923 char prompt[150]; 924 char *password; 925 const char *host = options.host_key_alias ? options.host_key_alias : 926 authctxt->host; 927 928 if (attempt++ >= options.number_of_password_prompts) 929 return 0; 930 931 if (attempt != 1) 932 error("Permission denied, please try again."); 933 934 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 935 authctxt->server_user, host); 936 password = read_passphrase(prompt, 0); 937 packet_start(SSH2_MSG_USERAUTH_REQUEST); 938 packet_put_cstring(authctxt->server_user); 939 packet_put_cstring(authctxt->service); 940 packet_put_cstring(authctxt->method->name); 941 packet_put_char(0); 942 packet_put_cstring(password); 943 explicit_bzero(password, strlen(password)); 944 free(password); 945 packet_add_padding(64); 946 packet_send(); 947 948 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 949 &input_userauth_passwd_changereq); 950 951 return 1; 952 } 953 954 /* 955 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 956 */ 957 /* ARGSUSED */ 958 int 959 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 960 { 961 Authctxt *authctxt = ctxt; 962 char *info, *lang, *password = NULL, *retype = NULL; 963 char prompt[150]; 964 const char *host = options.host_key_alias ? options.host_key_alias : 965 authctxt->host; 966 967 debug2("input_userauth_passwd_changereq"); 968 969 if (authctxt == NULL) 970 fatal("input_userauth_passwd_changereq: " 971 "no authentication context"); 972 973 info = packet_get_string(NULL); 974 lang = packet_get_string(NULL); 975 if (strlen(info) > 0) 976 logit("%s", info); 977 free(info); 978 free(lang); 979 packet_start(SSH2_MSG_USERAUTH_REQUEST); 980 packet_put_cstring(authctxt->server_user); 981 packet_put_cstring(authctxt->service); 982 packet_put_cstring(authctxt->method->name); 983 packet_put_char(1); /* additional info */ 984 snprintf(prompt, sizeof(prompt), 985 "Enter %.30s@%.128s's old password: ", 986 authctxt->server_user, host); 987 password = read_passphrase(prompt, 0); 988 packet_put_cstring(password); 989 explicit_bzero(password, strlen(password)); 990 free(password); 991 password = NULL; 992 while (password == NULL) { 993 snprintf(prompt, sizeof(prompt), 994 "Enter %.30s@%.128s's new password: ", 995 authctxt->server_user, host); 996 password = read_passphrase(prompt, RP_ALLOW_EOF); 997 if (password == NULL) { 998 /* bail out */ 999 return 0; 1000 } 1001 snprintf(prompt, sizeof(prompt), 1002 "Retype %.30s@%.128s's new password: ", 1003 authctxt->server_user, host); 1004 retype = read_passphrase(prompt, 0); 1005 if (strcmp(password, retype) != 0) { 1006 explicit_bzero(password, strlen(password)); 1007 free(password); 1008 logit("Mismatch; try again, EOF to quit."); 1009 password = NULL; 1010 } 1011 explicit_bzero(retype, strlen(retype)); 1012 free(retype); 1013 } 1014 packet_put_cstring(password); 1015 explicit_bzero(password, strlen(password)); 1016 free(password); 1017 packet_add_padding(64); 1018 packet_send(); 1019 1020 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1021 &input_userauth_passwd_changereq); 1022 return 0; 1023 } 1024 1025 static const char * 1026 identity_sign_encode(struct identity *id) 1027 { 1028 struct ssh *ssh = active_state; 1029 1030 if (id->key->type == KEY_RSA) { 1031 switch (ssh->kex->rsa_sha2) { 1032 case 256: 1033 return "rsa-sha2-256"; 1034 case 512: 1035 return "rsa-sha2-512"; 1036 } 1037 } 1038 return key_ssh_name(id->key); 1039 } 1040 1041 static int 1042 identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 1043 const u_char *data, size_t datalen, u_int compat) 1044 { 1045 Key *prv; 1046 int ret; 1047 const char *alg; 1048 1049 alg = identity_sign_encode(id); 1050 1051 /* the agent supports this key */ 1052 if (id->agent_fd != -1) 1053 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 1054 data, datalen, alg, compat); 1055 1056 /* 1057 * we have already loaded the private key or 1058 * the private key is stored in external hardware 1059 */ 1060 if (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT)) 1061 return (sshkey_sign(id->key, sigp, lenp, data, datalen, alg, 1062 compat)); 1063 /* load the private key from the file */ 1064 if ((prv = load_identity_file(id)) == NULL) 1065 return SSH_ERR_KEY_NOT_FOUND; 1066 ret = sshkey_sign(prv, sigp, lenp, data, datalen, alg, compat); 1067 sshkey_free(prv); 1068 return (ret); 1069 } 1070 1071 static int 1072 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1073 { 1074 Buffer b; 1075 Identity *private_id; 1076 u_char *blob, *signature; 1077 size_t slen; 1078 u_int bloblen, skip = 0; 1079 int matched, ret = -1, have_sig = 1; 1080 char *fp; 1081 1082 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1083 SSH_FP_DEFAULT)) == NULL) 1084 return 0; 1085 debug3("%s: %s %s", __func__, key_type(id->key), fp); 1086 free(fp); 1087 1088 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1089 /* we cannot handle this key */ 1090 debug3("sign_and_send_pubkey: cannot handle key"); 1091 return 0; 1092 } 1093 /* data to be signed */ 1094 buffer_init(&b); 1095 if (datafellows & SSH_OLD_SESSIONID) { 1096 buffer_append(&b, session_id2, session_id2_len); 1097 skip = session_id2_len; 1098 } else { 1099 buffer_put_string(&b, session_id2, session_id2_len); 1100 skip = buffer_len(&b); 1101 } 1102 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1103 buffer_put_cstring(&b, authctxt->server_user); 1104 buffer_put_cstring(&b, 1105 datafellows & SSH_BUG_PKSERVICE ? 1106 "ssh-userauth" : 1107 authctxt->service); 1108 if (datafellows & SSH_BUG_PKAUTH) { 1109 buffer_put_char(&b, have_sig); 1110 } else { 1111 buffer_put_cstring(&b, authctxt->method->name); 1112 buffer_put_char(&b, have_sig); 1113 buffer_put_cstring(&b, identity_sign_encode(id)); 1114 } 1115 buffer_put_string(&b, blob, bloblen); 1116 1117 /* 1118 * If the key is an certificate, try to find a matching private key 1119 * and use it to complete the signature. 1120 * If no such private key exists, fall back to trying the certificate 1121 * key itself in case it has a private half already loaded. 1122 */ 1123 if (key_is_cert(id->key)) { 1124 matched = 0; 1125 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1126 if (sshkey_equal_public(id->key, private_id->key) && 1127 id->key->type != private_id->key->type) { 1128 id = private_id; 1129 matched = 1; 1130 break; 1131 } 1132 } 1133 if (matched) { 1134 debug2("%s: using private key \"%s\"%s for " 1135 "certificate", __func__, id->filename, 1136 id->agent_fd != -1 ? " from agent" : ""); 1137 } else { 1138 debug("%s: no separate private key for certificate " 1139 "\"%s\"", __func__, id->filename); 1140 } 1141 } 1142 1143 /* generate signature */ 1144 ret = identity_sign(id, &signature, &slen, 1145 buffer_ptr(&b), buffer_len(&b), datafellows); 1146 if (ret != 0) { 1147 if (ret != SSH_ERR_KEY_NOT_FOUND) 1148 error("%s: signing failed: %s", __func__, ssh_err(ret)); 1149 free(blob); 1150 buffer_free(&b); 1151 return 0; 1152 } 1153 #ifdef DEBUG_PK 1154 buffer_dump(&b); 1155 #endif 1156 if (datafellows & SSH_BUG_PKSERVICE) { 1157 buffer_clear(&b); 1158 buffer_append(&b, session_id2, session_id2_len); 1159 skip = session_id2_len; 1160 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1161 buffer_put_cstring(&b, authctxt->server_user); 1162 buffer_put_cstring(&b, authctxt->service); 1163 buffer_put_cstring(&b, authctxt->method->name); 1164 buffer_put_char(&b, have_sig); 1165 if (!(datafellows & SSH_BUG_PKAUTH)) 1166 buffer_put_cstring(&b, key_ssh_name(id->key)); 1167 buffer_put_string(&b, blob, bloblen); 1168 } 1169 free(blob); 1170 1171 /* append signature */ 1172 buffer_put_string(&b, signature, slen); 1173 free(signature); 1174 1175 /* skip session id and packet type */ 1176 if (buffer_len(&b) < skip + 1) 1177 fatal("userauth_pubkey: internal error"); 1178 buffer_consume(&b, skip + 1); 1179 1180 /* put remaining data from buffer into packet */ 1181 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1182 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1183 buffer_free(&b); 1184 packet_send(); 1185 1186 return 1; 1187 } 1188 1189 static int 1190 send_pubkey_test(Authctxt *authctxt, Identity *id) 1191 { 1192 u_char *blob; 1193 u_int bloblen, have_sig = 0; 1194 1195 debug3("send_pubkey_test"); 1196 1197 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1198 /* we cannot handle this key */ 1199 debug3("send_pubkey_test: cannot handle key"); 1200 return 0; 1201 } 1202 /* register callback for USERAUTH_PK_OK message */ 1203 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1204 1205 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1206 packet_put_cstring(authctxt->server_user); 1207 packet_put_cstring(authctxt->service); 1208 packet_put_cstring(authctxt->method->name); 1209 packet_put_char(have_sig); 1210 if (!(datafellows & SSH_BUG_PKAUTH)) 1211 packet_put_cstring(identity_sign_encode(id)); 1212 packet_put_string(blob, bloblen); 1213 free(blob); 1214 packet_send(); 1215 return 1; 1216 } 1217 1218 static Key * 1219 load_identity_file(Identity *id) 1220 { 1221 Key *private = NULL; 1222 char prompt[300], *passphrase, *comment; 1223 int r, perm_ok = 0, quit = 0, i; 1224 struct stat st; 1225 1226 if (stat(id->filename, &st) < 0) { 1227 (id->userprovided ? logit : debug3)("no such identity: %s: %s", 1228 id->filename, strerror(errno)); 1229 return NULL; 1230 } 1231 snprintf(prompt, sizeof prompt, 1232 "Enter passphrase for key '%.100s': ", id->filename); 1233 for (i = 0; i <= options.number_of_password_prompts; i++) { 1234 if (i == 0) 1235 passphrase = xstrdup(""); 1236 else { 1237 passphrase = read_passphrase(prompt, 0); 1238 if (*passphrase == '\0') { 1239 debug2("no passphrase given, try next key"); 1240 free(passphrase); 1241 break; 1242 } 1243 } 1244 switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename, 1245 passphrase, &private, &comment, &perm_ok))) { 1246 case 0: 1247 break; 1248 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1249 if (options.batch_mode) { 1250 quit = 1; 1251 break; 1252 } 1253 if (i != 0) 1254 debug2("bad passphrase given, try again..."); 1255 break; 1256 case SSH_ERR_SYSTEM_ERROR: 1257 if (errno == ENOENT) { 1258 debug2("Load key \"%s\": %s", 1259 id->filename, ssh_err(r)); 1260 quit = 1; 1261 break; 1262 } 1263 /* FALLTHROUGH */ 1264 default: 1265 error("Load key \"%s\": %s", id->filename, ssh_err(r)); 1266 quit = 1; 1267 break; 1268 } 1269 if (!quit && private != NULL && id->agent_fd == -1 && 1270 !(id->key && id->isprivate)) 1271 maybe_add_key_to_agent(id->filename, private, comment, 1272 passphrase); 1273 if (i > 0) { 1274 explicit_bzero(passphrase, strlen(passphrase)); 1275 free(passphrase); 1276 } 1277 free(comment); 1278 if (private != NULL || quit) 1279 break; 1280 } 1281 return private; 1282 } 1283 1284 /* 1285 * try keys in the following order: 1286 * 1. certificates listed in the config file 1287 * 2. other input certificates 1288 * 3. agent keys that are found in the config file 1289 * 4. other agent keys 1290 * 5. keys that are only listed in the config file 1291 */ 1292 static void 1293 pubkey_prepare(Authctxt *authctxt) 1294 { 1295 struct identity *id, *id2, *tmp; 1296 struct idlist agent, files, *preferred; 1297 struct sshkey *key; 1298 int agent_fd = -1, i, r, found; 1299 size_t j; 1300 struct ssh_identitylist *idlist; 1301 1302 TAILQ_INIT(&agent); /* keys from the agent */ 1303 TAILQ_INIT(&files); /* keys from the config file */ 1304 preferred = &authctxt->keys; 1305 TAILQ_INIT(preferred); /* preferred order of keys */ 1306 1307 /* list of keys stored in the filesystem and PKCS#11 */ 1308 for (i = 0; i < options.num_identity_files; i++) { 1309 key = options.identity_keys[i]; 1310 if (key && key->type == KEY_RSA1) 1311 continue; 1312 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1313 continue; 1314 options.identity_keys[i] = NULL; 1315 id = xcalloc(1, sizeof(*id)); 1316 id->agent_fd = -1; 1317 id->key = key; 1318 id->filename = xstrdup(options.identity_files[i]); 1319 id->userprovided = options.identity_file_userprovided[i]; 1320 TAILQ_INSERT_TAIL(&files, id, next); 1321 } 1322 /* list of certificates specified by user */ 1323 for (i = 0; i < options.num_certificate_files; i++) { 1324 key = options.certificates[i]; 1325 if (!key_is_cert(key) || key->cert == NULL || 1326 key->cert->type != SSH2_CERT_TYPE_USER) 1327 continue; 1328 id = xcalloc(1, sizeof(*id)); 1329 id->agent_fd = -1; 1330 id->key = key; 1331 id->filename = xstrdup(options.certificate_files[i]); 1332 id->userprovided = options.certificate_file_userprovided[i]; 1333 TAILQ_INSERT_TAIL(preferred, id, next); 1334 } 1335 /* list of keys supported by the agent */ 1336 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1337 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1338 debug("%s: ssh_get_authentication_socket: %s", 1339 __func__, ssh_err(r)); 1340 } else if ((r = ssh_fetch_identitylist(agent_fd, 2, &idlist)) != 0) { 1341 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1342 debug("%s: ssh_fetch_identitylist: %s", 1343 __func__, ssh_err(r)); 1344 close(agent_fd); 1345 } else { 1346 for (j = 0; j < idlist->nkeys; j++) { 1347 found = 0; 1348 TAILQ_FOREACH(id, &files, next) { 1349 /* 1350 * agent keys from the config file are 1351 * preferred 1352 */ 1353 if (sshkey_equal(idlist->keys[j], id->key)) { 1354 TAILQ_REMOVE(&files, id, next); 1355 TAILQ_INSERT_TAIL(preferred, id, next); 1356 id->agent_fd = agent_fd; 1357 found = 1; 1358 break; 1359 } 1360 } 1361 if (!found && !options.identities_only) { 1362 id = xcalloc(1, sizeof(*id)); 1363 /* XXX "steals" key/comment from idlist */ 1364 id->key = idlist->keys[j]; 1365 id->filename = idlist->comments[j]; 1366 idlist->keys[j] = NULL; 1367 idlist->comments[j] = NULL; 1368 id->agent_fd = agent_fd; 1369 TAILQ_INSERT_TAIL(&agent, id, next); 1370 } 1371 } 1372 ssh_free_identitylist(idlist); 1373 /* append remaining agent keys */ 1374 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1375 TAILQ_REMOVE(&agent, id, next); 1376 TAILQ_INSERT_TAIL(preferred, id, next); 1377 } 1378 authctxt->agent_fd = agent_fd; 1379 } 1380 /* Prefer PKCS11 keys that are explicitly listed */ 1381 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1382 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1383 continue; 1384 found = 0; 1385 TAILQ_FOREACH(id2, &files, next) { 1386 if (id2->key == NULL || 1387 (id2->key->flags & SSHKEY_FLAG_EXT) == 0) 1388 continue; 1389 if (sshkey_equal(id->key, id2->key)) { 1390 TAILQ_REMOVE(&files, id, next); 1391 TAILQ_INSERT_TAIL(preferred, id, next); 1392 found = 1; 1393 break; 1394 } 1395 } 1396 /* If IdentitiesOnly set and key not found then don't use it */ 1397 if (!found && options.identities_only) { 1398 TAILQ_REMOVE(&files, id, next); 1399 explicit_bzero(id, sizeof(*id)); 1400 free(id); 1401 } 1402 } 1403 /* append remaining keys from the config file */ 1404 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1405 TAILQ_REMOVE(&files, id, next); 1406 TAILQ_INSERT_TAIL(preferred, id, next); 1407 } 1408 /* finally, filter by PubkeyAcceptedKeyTypes */ 1409 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1410 if (id->key != NULL && 1411 match_pattern_list(sshkey_ssh_name(id->key), 1412 options.pubkey_key_types, 0) != 1) { 1413 debug("Skipping %s key %s - " 1414 "not in PubkeyAcceptedKeyTypes", 1415 sshkey_ssh_name(id->key), id->filename); 1416 TAILQ_REMOVE(preferred, id, next); 1417 sshkey_free(id->key); 1418 free(id->filename); 1419 memset(id, 0, sizeof(*id)); 1420 continue; 1421 } 1422 debug2("key: %s (%p)%s%s", id->filename, id->key, 1423 id->userprovided ? ", explicit" : "", 1424 id->agent_fd != -1 ? ", agent" : ""); 1425 } 1426 } 1427 1428 static void 1429 pubkey_cleanup(Authctxt *authctxt) 1430 { 1431 Identity *id; 1432 1433 if (authctxt->agent_fd != -1) 1434 ssh_close_authentication_socket(authctxt->agent_fd); 1435 for (id = TAILQ_FIRST(&authctxt->keys); id; 1436 id = TAILQ_FIRST(&authctxt->keys)) { 1437 TAILQ_REMOVE(&authctxt->keys, id, next); 1438 sshkey_free(id->key); 1439 free(id->filename); 1440 free(id); 1441 } 1442 } 1443 1444 static int 1445 try_identity(Identity *id) 1446 { 1447 if (!id->key) 1448 return (0); 1449 if (key_type_plain(id->key->type) == KEY_RSA && 1450 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1451 debug("Skipped %s key %s for RSA/MD5 server", 1452 key_type(id->key), id->filename); 1453 return (0); 1454 } 1455 return (id->key->type != KEY_RSA1); 1456 } 1457 1458 int 1459 userauth_pubkey(Authctxt *authctxt) 1460 { 1461 Identity *id; 1462 int sent = 0; 1463 1464 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1465 if (id->tried++) 1466 return (0); 1467 /* move key to the end of the queue */ 1468 TAILQ_REMOVE(&authctxt->keys, id, next); 1469 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1470 /* 1471 * send a test message if we have the public key. for 1472 * encrypted keys we cannot do this and have to load the 1473 * private key instead 1474 */ 1475 if (id->key != NULL) { 1476 if (try_identity(id)) { 1477 debug("Offering %s public key: %s", 1478 key_type(id->key), id->filename); 1479 sent = send_pubkey_test(authctxt, id); 1480 } 1481 } else { 1482 debug("Trying private key: %s", id->filename); 1483 id->key = load_identity_file(id); 1484 if (id->key != NULL) { 1485 if (try_identity(id)) { 1486 id->isprivate = 1; 1487 sent = sign_and_send_pubkey( 1488 authctxt, id); 1489 } 1490 key_free(id->key); 1491 id->key = NULL; 1492 } 1493 } 1494 if (sent) 1495 return (sent); 1496 } 1497 return (0); 1498 } 1499 1500 /* 1501 * Send userauth request message specifying keyboard-interactive method. 1502 */ 1503 int 1504 userauth_kbdint(Authctxt *authctxt) 1505 { 1506 static int attempt = 0; 1507 1508 if (attempt++ >= options.number_of_password_prompts) 1509 return 0; 1510 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1511 if (attempt > 1 && !authctxt->info_req_seen) { 1512 debug3("userauth_kbdint: disable: no info_req_seen"); 1513 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1514 return 0; 1515 } 1516 1517 debug2("userauth_kbdint"); 1518 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1519 packet_put_cstring(authctxt->server_user); 1520 packet_put_cstring(authctxt->service); 1521 packet_put_cstring(authctxt->method->name); 1522 packet_put_cstring(""); /* lang */ 1523 packet_put_cstring(options.kbd_interactive_devices ? 1524 options.kbd_interactive_devices : ""); 1525 packet_send(); 1526 1527 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1528 return 1; 1529 } 1530 1531 /* 1532 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1533 */ 1534 int 1535 input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1536 { 1537 Authctxt *authctxt = ctxt; 1538 char *name, *inst, *lang, *prompt, *response; 1539 u_int num_prompts, i; 1540 int echo = 0; 1541 1542 debug2("input_userauth_info_req"); 1543 1544 if (authctxt == NULL) 1545 fatal("input_userauth_info_req: no authentication context"); 1546 1547 authctxt->info_req_seen = 1; 1548 1549 name = packet_get_string(NULL); 1550 inst = packet_get_string(NULL); 1551 lang = packet_get_string(NULL); 1552 if (strlen(name) > 0) 1553 logit("%s", name); 1554 if (strlen(inst) > 0) 1555 logit("%s", inst); 1556 free(name); 1557 free(inst); 1558 free(lang); 1559 1560 num_prompts = packet_get_int(); 1561 /* 1562 * Begin to build info response packet based on prompts requested. 1563 * We commit to providing the correct number of responses, so if 1564 * further on we run into a problem that prevents this, we have to 1565 * be sure and clean this up and send a correct error response. 1566 */ 1567 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1568 packet_put_int(num_prompts); 1569 1570 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1571 for (i = 0; i < num_prompts; i++) { 1572 prompt = packet_get_string(NULL); 1573 echo = packet_get_char(); 1574 1575 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1576 1577 packet_put_cstring(response); 1578 explicit_bzero(response, strlen(response)); 1579 free(response); 1580 free(prompt); 1581 } 1582 packet_check_eom(); /* done with parsing incoming message. */ 1583 1584 packet_add_padding(64); 1585 packet_send(); 1586 return 0; 1587 } 1588 1589 static int 1590 ssh_keysign(struct sshkey *key, u_char **sigp, size_t *lenp, 1591 const u_char *data, size_t datalen) 1592 { 1593 struct sshbuf *b; 1594 struct stat st; 1595 pid_t pid; 1596 int i, r, to[2], from[2], status, sock = packet_get_connection_in(); 1597 u_char rversion = 0, version = 2; 1598 void (*osigchld)(int); 1599 1600 *sigp = NULL; 1601 *lenp = 0; 1602 1603 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1604 error("%s: not installed: %s", __func__, strerror(errno)); 1605 return -1; 1606 } 1607 if (fflush(stdout) != 0) { 1608 error("%s: fflush: %s", __func__, strerror(errno)); 1609 return -1; 1610 } 1611 if (pipe(to) < 0) { 1612 error("%s: pipe: %s", __func__, strerror(errno)); 1613 return -1; 1614 } 1615 if (pipe(from) < 0) { 1616 error("%s: pipe: %s", __func__, strerror(errno)); 1617 return -1; 1618 } 1619 if ((pid = fork()) < 0) { 1620 error("%s: fork: %s", __func__, strerror(errno)); 1621 return -1; 1622 } 1623 osigchld = signal(SIGCHLD, SIG_DFL); 1624 if (pid == 0) { 1625 /* keep the socket on exec */ 1626 fcntl(sock, F_SETFD, 0); 1627 permanently_drop_suid(getuid()); 1628 close(from[0]); 1629 if (dup2(from[1], STDOUT_FILENO) < 0) 1630 fatal("%s: dup2: %s", __func__, strerror(errno)); 1631 close(to[1]); 1632 if (dup2(to[0], STDIN_FILENO) < 0) 1633 fatal("%s: dup2: %s", __func__, strerror(errno)); 1634 close(from[1]); 1635 close(to[0]); 1636 /* Close everything but stdio and the socket */ 1637 for (i = STDERR_FILENO + 1; i < sock; i++) 1638 close(i); 1639 if (closefrom(sock + 1) < 0) 1640 fatal("%s: closefrom: %s", __func__, strerror(errno)); 1641 debug3("%s: [child] pid=%ld, exec %s", 1642 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1643 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL); 1644 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1645 strerror(errno)); 1646 } 1647 close(from[1]); 1648 close(to[0]); 1649 1650 if ((b = sshbuf_new()) == NULL) 1651 fatal("%s: sshbuf_new failed", __func__); 1652 /* send # of sock, data to be signed */ 1653 if ((r = sshbuf_put_u32(b, sock) != 0) || 1654 (r = sshbuf_put_string(b, data, datalen)) != 0) 1655 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1656 if (ssh_msg_send(to[1], version, b) == -1) 1657 fatal("%s: couldn't send request", __func__); 1658 sshbuf_reset(b); 1659 r = ssh_msg_recv(from[0], b); 1660 close(from[0]); 1661 close(to[1]); 1662 if (r < 0) { 1663 error("%s: no reply", __func__); 1664 goto fail; 1665 } 1666 1667 errno = 0; 1668 while (waitpid(pid, &status, 0) < 0) { 1669 if (errno != EINTR) { 1670 error("%s: waitpid %ld: %s", 1671 __func__, (long)pid, strerror(errno)); 1672 goto fail; 1673 } 1674 } 1675 if (!WIFEXITED(status)) { 1676 error("%s: exited abnormally", __func__); 1677 goto fail; 1678 } 1679 if (WEXITSTATUS(status) != 0) { 1680 error("%s: exited with status %d", 1681 __func__, WEXITSTATUS(status)); 1682 goto fail; 1683 } 1684 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 1685 error("%s: buffer error: %s", __func__, ssh_err(r)); 1686 goto fail; 1687 } 1688 if (rversion != version) { 1689 error("%s: bad version", __func__); 1690 goto fail; 1691 } 1692 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 1693 error("%s: buffer error: %s", __func__, ssh_err(r)); 1694 fail: 1695 signal(SIGCHLD, osigchld); 1696 sshbuf_free(b); 1697 return -1; 1698 } 1699 signal(SIGCHLD, osigchld); 1700 sshbuf_free(b); 1701 1702 return 0; 1703 } 1704 1705 int 1706 userauth_hostbased(Authctxt *authctxt) 1707 { 1708 struct ssh *ssh = active_state; 1709 struct sshkey *private = NULL; 1710 struct sshbuf *b = NULL; 1711 const char *service; 1712 u_char *sig = NULL, *keyblob = NULL; 1713 char *fp = NULL, *chost = NULL, *lname = NULL; 1714 size_t siglen = 0, keylen = 0; 1715 int i, r, success = 0; 1716 1717 if (authctxt->ktypes == NULL) { 1718 authctxt->oktypes = xstrdup(options.hostbased_key_types); 1719 authctxt->ktypes = authctxt->oktypes; 1720 } 1721 1722 /* 1723 * Work through each listed type pattern in HostbasedKeyTypes, 1724 * trying each hostkey that matches the type in turn. 1725 */ 1726 for (;;) { 1727 if (authctxt->active_ktype == NULL) 1728 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 1729 if (authctxt->active_ktype == NULL || 1730 *authctxt->active_ktype == '\0') 1731 break; 1732 debug3("%s: trying key type %s", __func__, 1733 authctxt->active_ktype); 1734 1735 /* check for a useful key */ 1736 private = NULL; 1737 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 1738 if (authctxt->sensitive->keys[i] == NULL || 1739 authctxt->sensitive->keys[i]->type == KEY_RSA1 || 1740 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 1741 continue; 1742 if (match_pattern_list( 1743 sshkey_ssh_name(authctxt->sensitive->keys[i]), 1744 authctxt->active_ktype, 0) != 1) 1745 continue; 1746 /* we take and free the key */ 1747 private = authctxt->sensitive->keys[i]; 1748 authctxt->sensitive->keys[i] = NULL; 1749 break; 1750 } 1751 /* Found one */ 1752 if (private != NULL) 1753 break; 1754 /* No more keys of this type; advance */ 1755 authctxt->active_ktype = NULL; 1756 } 1757 if (private == NULL) { 1758 free(authctxt->oktypes); 1759 authctxt->oktypes = authctxt->ktypes = NULL; 1760 authctxt->active_ktype = NULL; 1761 debug("No more client hostkeys for hostbased authentication."); 1762 goto out; 1763 } 1764 1765 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 1766 SSH_FP_DEFAULT)) == NULL) { 1767 error("%s: sshkey_fingerprint failed", __func__); 1768 goto out; 1769 } 1770 debug("%s: trying hostkey %s %s", 1771 __func__, sshkey_ssh_name(private), fp); 1772 1773 /* figure out a name for the client host */ 1774 if ((lname = get_local_name(packet_get_connection_in())) == NULL) { 1775 error("%s: cannot get local ipaddr/name", __func__); 1776 goto out; 1777 } 1778 1779 /* XXX sshbuf_put_stringf? */ 1780 xasprintf(&chost, "%s.", lname); 1781 debug2("%s: chost %s", __func__, chost); 1782 1783 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1784 authctxt->service; 1785 1786 /* construct data */ 1787 if ((b = sshbuf_new()) == NULL) { 1788 error("%s: sshbuf_new failed", __func__); 1789 goto out; 1790 } 1791 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 1792 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 1793 goto out; 1794 } 1795 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 1796 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1797 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1798 (r = sshbuf_put_cstring(b, service)) != 0 || 1799 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1800 (r = sshbuf_put_cstring(b, key_ssh_name(private))) != 0 || 1801 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 1802 (r = sshbuf_put_cstring(b, chost)) != 0 || 1803 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 1804 error("%s: buffer error: %s", __func__, ssh_err(r)); 1805 goto out; 1806 } 1807 1808 #ifdef DEBUG_PK 1809 sshbuf_dump(b, stderr); 1810 #endif 1811 if (authctxt->sensitive->external_keysign) 1812 r = ssh_keysign(private, &sig, &siglen, 1813 sshbuf_ptr(b), sshbuf_len(b)); 1814 else if ((r = sshkey_sign(private, &sig, &siglen, 1815 sshbuf_ptr(b), sshbuf_len(b), NULL, datafellows)) != 0) 1816 debug("%s: sshkey_sign: %s", __func__, ssh_err(r)); 1817 if (r != 0) { 1818 error("sign using hostkey %s %s failed", 1819 sshkey_ssh_name(private), fp); 1820 goto out; 1821 } 1822 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1823 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1824 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1825 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1826 (r = sshpkt_put_cstring(ssh, key_ssh_name(private))) != 0 || 1827 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 1828 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 1829 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 1830 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 1831 (r = sshpkt_send(ssh)) != 0) { 1832 error("%s: packet error: %s", __func__, ssh_err(r)); 1833 goto out; 1834 } 1835 success = 1; 1836 1837 out: 1838 if (sig != NULL) { 1839 explicit_bzero(sig, siglen); 1840 free(sig); 1841 } 1842 free(keyblob); 1843 free(lname); 1844 free(fp); 1845 free(chost); 1846 sshkey_free(private); 1847 sshbuf_free(b); 1848 1849 return success; 1850 } 1851 1852 #if KRB5 1853 static int 1854 ssh_krb5_helper(krb5_data *ap) 1855 { 1856 krb5_context xcontext = NULL; /* XXX share with ssh1 */ 1857 krb5_auth_context xauth_context = NULL; 1858 1859 krb5_context *context; 1860 krb5_auth_context *auth_context; 1861 krb5_error_code problem; 1862 const char *tkfile; 1863 struct stat buf; 1864 krb5_ccache ccache = NULL; 1865 const char *remotehost; 1866 int ret; 1867 const char *errtxt; 1868 struct ssh *ssh = active_state; /* XXX */ 1869 1870 memset(ap, 0, sizeof(*ap)); 1871 1872 context = &xcontext; 1873 auth_context = &xauth_context; 1874 1875 problem = krb5_init_context(context); 1876 if (problem) { 1877 debug("Kerberos v5: krb5_init_context failed"); 1878 ret = 0; 1879 goto out; 1880 } 1881 1882 tkfile = krb5_cc_default_name(*context); 1883 if (strncmp(tkfile, "FILE:", 5) == 0) 1884 tkfile += 5; 1885 1886 if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) { 1887 debug("Kerberos v5: could not get default ccache (permission denied)."); 1888 ret = 0; 1889 goto out; 1890 } 1891 1892 problem = krb5_cc_default(*context, &ccache); 1893 if (problem) { 1894 errtxt = krb5_get_error_message(*context, problem); 1895 if (errtxt != NULL) { 1896 debug("Kerberos v5: krb5_cc_default failed: %s", 1897 errtxt); 1898 krb5_free_error_message(*context, errtxt); 1899 } else 1900 debug("Kerberos v5: krb5_cc_default failed: %d", 1901 problem); 1902 ret = 0; 1903 goto out; 1904 } 1905 1906 remotehost = auth_get_canonical_hostname(ssh, 1); 1907 1908 problem = krb5_mk_req(*context, auth_context, AP_OPTS_MUTUAL_REQUIRED, 1909 "host", remotehost, NULL, ccache, ap); 1910 if (problem) { 1911 errtxt = krb5_get_error_message(*context, problem); 1912 if (errtxt != NULL) { 1913 debug("Kerberos v5: krb5_mk_req failed: %s", errtxt); 1914 krb5_free_error_message(*context, errtxt); 1915 } else 1916 debug("Kerberos v5: krb5_mk_req failed: %d", problem); 1917 ret = 0; 1918 goto out; 1919 } 1920 ret = 1; 1921 1922 out: 1923 if (ccache != NULL) 1924 krb5_cc_close(*context, ccache); 1925 if (*auth_context) 1926 krb5_auth_con_free(*context, *auth_context); 1927 if (*context) 1928 krb5_free_context(*context); 1929 return (ret); 1930 } 1931 1932 int 1933 userauth_kerberos(Authctxt *authctxt) 1934 { 1935 krb5_data ap; 1936 1937 if (ssh_krb5_helper(&ap) == 0) 1938 return (0); 1939 1940 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1941 packet_put_cstring(authctxt->server_user); 1942 packet_put_cstring(authctxt->service); 1943 packet_put_cstring(authctxt->method->name); 1944 packet_put_string(ap.data, ap.length); 1945 packet_send(); 1946 1947 krb5_data_free(&ap); 1948 return (1); 1949 } 1950 #endif 1951 1952 /* find auth method */ 1953 1954 /* 1955 * given auth method name, if configurable options permit this method fill 1956 * in auth_ident field and return true, otherwise return false. 1957 */ 1958 static int 1959 authmethod_is_enabled(Authmethod *method) 1960 { 1961 if (method == NULL) 1962 return 0; 1963 /* return false if options indicate this method is disabled */ 1964 if (method->enabled == NULL || *method->enabled == 0) 1965 return 0; 1966 /* return false if batch mode is enabled but method needs interactive mode */ 1967 if (method->batch_flag != NULL && *method->batch_flag != 0) 1968 return 0; 1969 return 1; 1970 } 1971 1972 static Authmethod * 1973 authmethod_lookup(const char *name) 1974 { 1975 Authmethod *method = NULL; 1976 if (name != NULL) 1977 for (method = authmethods; method->name != NULL; method++) 1978 if (strcmp(name, method->name) == 0) 1979 return method; 1980 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1981 return NULL; 1982 } 1983 1984 /* XXX internal state */ 1985 static Authmethod *current = NULL; 1986 static char *supported = NULL; 1987 static char *preferred = NULL; 1988 1989 /* 1990 * Given the authentication method list sent by the server, return the 1991 * next method we should try. If the server initially sends a nil list, 1992 * use a built-in default list. 1993 */ 1994 static Authmethod * 1995 authmethod_get(char *authlist) 1996 { 1997 char *name = NULL; 1998 u_int next; 1999 2000 /* Use a suitable default if we're passed a nil list. */ 2001 if (authlist == NULL || strlen(authlist) == 0) 2002 authlist = options.preferred_authentications; 2003 2004 if (supported == NULL || strcmp(authlist, supported) != 0) { 2005 debug3("start over, passed a different list %s", authlist); 2006 free(supported); 2007 supported = xstrdup(authlist); 2008 preferred = options.preferred_authentications; 2009 debug3("preferred %s", preferred); 2010 current = NULL; 2011 } else if (current != NULL && authmethod_is_enabled(current)) 2012 return current; 2013 2014 for (;;) { 2015 if ((name = match_list(preferred, supported, &next)) == NULL) { 2016 debug("No more authentication methods to try."); 2017 current = NULL; 2018 return NULL; 2019 } 2020 preferred += next; 2021 debug3("authmethod_lookup %s", name); 2022 debug3("remaining preferred: %s", preferred); 2023 if ((current = authmethod_lookup(name)) != NULL && 2024 authmethod_is_enabled(current)) { 2025 debug3("authmethod_is_enabled %s", name); 2026 debug("Next authentication method: %s", name); 2027 free(name); 2028 return current; 2029 } 2030 free(name); 2031 } 2032 } 2033 2034 static char * 2035 authmethods_get(void) 2036 { 2037 Authmethod *method = NULL; 2038 Buffer b; 2039 char *list; 2040 2041 buffer_init(&b); 2042 for (method = authmethods; method->name != NULL; method++) { 2043 if (authmethod_is_enabled(method)) { 2044 if (buffer_len(&b) > 0) 2045 buffer_append(&b, ",", 1); 2046 buffer_append(&b, method->name, strlen(method->name)); 2047 } 2048 } 2049 if ((list = sshbuf_dup_string(&b)) == NULL) 2050 fatal("%s: sshbuf_dup_string failed", __func__); 2051 buffer_free(&b); 2052 return list; 2053 } 2054 2055