1 /* $OpenBSD: sshconnect2.c,v 1.266 2017/08/27 00:38:41 dtucker Exp $ */ 2 /* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include "includes.h" 28 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <sys/wait.h> 32 #include <sys/stat.h> 33 34 #include <errno.h> 35 #include <fcntl.h> 36 #include <netdb.h> 37 #include <pwd.h> 38 #include <signal.h> 39 #include <stdarg.h> 40 #include <stdio.h> 41 #include <string.h> 42 #include <unistd.h> 43 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) && !defined(BROKEN_STRNVIS) 44 #include <vis.h> 45 #endif 46 47 #include "openbsd-compat/sys-queue.h" 48 49 #include "xmalloc.h" 50 #include "ssh.h" 51 #include "ssh2.h" 52 #include "buffer.h" 53 #include "packet.h" 54 #include "compat.h" 55 #include "cipher.h" 56 #include "key.h" 57 #include "kex.h" 58 #include "myproposal.h" 59 #include "sshconnect.h" 60 #include "authfile.h" 61 #include "dh.h" 62 #include "authfd.h" 63 #include "log.h" 64 #include "misc.h" 65 #include "readconf.h" 66 #include "match.h" 67 #include "dispatch.h" 68 #include "canohost.h" 69 #include "msg.h" 70 #include "pathnames.h" 71 #include "uidswap.h" 72 #include "hostfile.h" 73 #include "ssherr.h" 74 #include "utf8.h" 75 76 #ifdef GSSAPI 77 #include "ssh-gss.h" 78 #endif 79 80 /* import */ 81 extern char *client_version_string; 82 extern char *server_version_string; 83 extern Options options; 84 85 /* 86 * SSH2 key exchange 87 */ 88 89 u_char *session_id2 = NULL; 90 u_int session_id2_len = 0; 91 92 char *xxx_host; 93 struct sockaddr *xxx_hostaddr; 94 95 static int 96 verify_host_key_callback(struct sshkey *hostkey, struct ssh *ssh) 97 { 98 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 99 fatal("Host key verification failed."); 100 return 0; 101 } 102 103 static char * 104 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 105 { 106 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 107 size_t maxlen; 108 struct hostkeys *hostkeys; 109 int ktype; 110 u_int i; 111 112 /* Find all hostkeys for this hostname */ 113 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 114 hostkeys = init_hostkeys(); 115 for (i = 0; i < options.num_user_hostfiles; i++) 116 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 117 for (i = 0; i < options.num_system_hostfiles; i++) 118 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 119 120 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 121 maxlen = strlen(avail) + 1; 122 first = xmalloc(maxlen); 123 last = xmalloc(maxlen); 124 *first = *last = '\0'; 125 126 #define ALG_APPEND(to, from) \ 127 do { \ 128 if (*to != '\0') \ 129 strlcat(to, ",", maxlen); \ 130 strlcat(to, from, maxlen); \ 131 } while (0) 132 133 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 134 if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC) 135 fatal("%s: unknown alg %s", __func__, alg); 136 if (lookup_key_in_hostkeys_by_type(hostkeys, 137 sshkey_type_plain(ktype), NULL)) 138 ALG_APPEND(first, alg); 139 else 140 ALG_APPEND(last, alg); 141 } 142 #undef ALG_APPEND 143 xasprintf(&ret, "%s%s%s", first, 144 (*first == '\0' || *last == '\0') ? "" : ",", last); 145 if (*first != '\0') 146 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 147 148 free(first); 149 free(last); 150 free(hostname); 151 free(oavail); 152 free_hostkeys(hostkeys); 153 154 return ret; 155 } 156 157 void 158 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 159 { 160 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; 161 char *s; 162 struct kex *kex; 163 int r; 164 165 xxx_host = host; 166 xxx_hostaddr = hostaddr; 167 168 if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL) 169 fatal("%s: kex_names_cat", __func__); 170 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s); 171 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 172 compat_cipher_proposal(options.ciphers); 173 myproposal[PROPOSAL_ENC_ALGS_STOC] = 174 compat_cipher_proposal(options.ciphers); 175 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 176 myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ? 177 "zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib"; 178 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 179 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 180 if (options.hostkeyalgorithms != NULL) { 181 if (kex_assemble_names(KEX_DEFAULT_PK_ALG, 182 &options.hostkeyalgorithms) != 0) 183 fatal("%s: kex_assemble_namelist", __func__); 184 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 185 compat_pkalg_proposal(options.hostkeyalgorithms); 186 } else { 187 /* Enforce default */ 188 options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG); 189 /* Prefer algorithms that we already have keys for */ 190 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 191 compat_pkalg_proposal( 192 order_hostkeyalgs(host, hostaddr, port)); 193 } 194 195 if (options.rekey_limit || options.rekey_interval) 196 packet_set_rekey_limits(options.rekey_limit, 197 options.rekey_interval); 198 199 /* start key exchange */ 200 if ((r = kex_setup(active_state, myproposal)) != 0) 201 fatal("kex_setup: %s", ssh_err(r)); 202 kex = active_state->kex; 203 #ifdef WITH_OPENSSL 204 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 205 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 206 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client; 207 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client; 208 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client; 209 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 210 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 211 # ifdef OPENSSL_HAS_ECC 212 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 213 # endif 214 #endif 215 kex->kex[KEX_C25519_SHA256] = kexc25519_client; 216 kex->client_version_string=client_version_string; 217 kex->server_version_string=server_version_string; 218 kex->verify_host_key=&verify_host_key_callback; 219 220 ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done); 221 222 /* remove ext-info from the KEX proposals for rekeying */ 223 myproposal[PROPOSAL_KEX_ALGS] = 224 compat_kex_proposal(options.kex_algorithms); 225 if ((r = kex_prop2buf(kex->my, myproposal)) != 0) 226 fatal("kex_prop2buf: %s", ssh_err(r)); 227 228 session_id2 = kex->session_id; 229 session_id2_len = kex->session_id_len; 230 231 #ifdef DEBUG_KEXDH 232 /* send 1st encrypted/maced/compressed message */ 233 packet_start(SSH2_MSG_IGNORE); 234 packet_put_cstring("markus"); 235 packet_send(); 236 packet_write_wait(); 237 #endif 238 } 239 240 /* 241 * Authenticate user 242 */ 243 244 typedef struct cauthctxt Authctxt; 245 typedef struct cauthmethod Authmethod; 246 typedef struct identity Identity; 247 typedef struct idlist Idlist; 248 249 struct identity { 250 TAILQ_ENTRY(identity) next; 251 int agent_fd; /* >=0 if agent supports key */ 252 struct sshkey *key; /* public/private key */ 253 char *filename; /* comment for agent-only keys */ 254 int tried; 255 int isprivate; /* key points to the private key */ 256 int userprovided; 257 }; 258 TAILQ_HEAD(idlist, identity); 259 260 struct cauthctxt { 261 const char *server_user; 262 const char *local_user; 263 const char *host; 264 const char *service; 265 struct cauthmethod *method; 266 sig_atomic_t success; 267 char *authlist; 268 int attempt; 269 /* pubkey */ 270 struct idlist keys; 271 int agent_fd; 272 /* hostbased */ 273 Sensitive *sensitive; 274 char *oktypes, *ktypes; 275 const char *active_ktype; 276 /* kbd-interactive */ 277 int info_req_seen; 278 /* generic */ 279 void *methoddata; 280 }; 281 282 struct cauthmethod { 283 char *name; /* string to compare against server's list */ 284 int (*userauth)(Authctxt *authctxt); 285 void (*cleanup)(Authctxt *authctxt); 286 int *enabled; /* flag in option struct that enables method */ 287 int *batch_flag; /* flag in option struct that disables method */ 288 }; 289 290 int input_userauth_service_accept(int, u_int32_t, struct ssh *); 291 int input_userauth_ext_info(int, u_int32_t, struct ssh *); 292 int input_userauth_success(int, u_int32_t, struct ssh *); 293 int input_userauth_success_unexpected(int, u_int32_t, struct ssh *); 294 int input_userauth_failure(int, u_int32_t, struct ssh *); 295 int input_userauth_banner(int, u_int32_t, struct ssh *); 296 int input_userauth_error(int, u_int32_t, struct ssh *); 297 int input_userauth_info_req(int, u_int32_t, struct ssh *); 298 int input_userauth_pk_ok(int, u_int32_t, struct ssh *); 299 int input_userauth_passwd_changereq(int, u_int32_t, struct ssh *); 300 301 int userauth_none(Authctxt *); 302 int userauth_pubkey(Authctxt *); 303 int userauth_passwd(Authctxt *); 304 int userauth_kbdint(Authctxt *); 305 int userauth_hostbased(Authctxt *); 306 307 #ifdef GSSAPI 308 int userauth_gssapi(Authctxt *authctxt); 309 int input_gssapi_response(int type, u_int32_t, struct ssh *); 310 int input_gssapi_token(int type, u_int32_t, struct ssh *); 311 int input_gssapi_hash(int type, u_int32_t, struct ssh *); 312 int input_gssapi_error(int, u_int32_t, struct ssh *); 313 int input_gssapi_errtok(int, u_int32_t, struct ssh *); 314 #endif 315 316 void userauth(Authctxt *, char *); 317 318 static int sign_and_send_pubkey(Authctxt *, Identity *); 319 static void pubkey_prepare(Authctxt *); 320 static void pubkey_cleanup(Authctxt *); 321 static void pubkey_reset(Authctxt *); 322 static struct sshkey *load_identity_file(Identity *); 323 324 static Authmethod *authmethod_get(char *authlist); 325 static Authmethod *authmethod_lookup(const char *name); 326 static char *authmethods_get(void); 327 328 Authmethod authmethods[] = { 329 #ifdef GSSAPI 330 {"gssapi-with-mic", 331 userauth_gssapi, 332 NULL, 333 &options.gss_authentication, 334 NULL}, 335 #endif 336 {"hostbased", 337 userauth_hostbased, 338 NULL, 339 &options.hostbased_authentication, 340 NULL}, 341 {"publickey", 342 userauth_pubkey, 343 NULL, 344 &options.pubkey_authentication, 345 NULL}, 346 {"keyboard-interactive", 347 userauth_kbdint, 348 NULL, 349 &options.kbd_interactive_authentication, 350 &options.batch_mode}, 351 {"password", 352 userauth_passwd, 353 NULL, 354 &options.password_authentication, 355 &options.batch_mode}, 356 {"none", 357 userauth_none, 358 NULL, 359 NULL, 360 NULL}, 361 {NULL, NULL, NULL, NULL, NULL} 362 }; 363 364 void 365 ssh_userauth2(const char *local_user, const char *server_user, char *host, 366 Sensitive *sensitive) 367 { 368 struct ssh *ssh = active_state; 369 Authctxt authctxt; 370 int r; 371 372 if (options.challenge_response_authentication) 373 options.kbd_interactive_authentication = 1; 374 if (options.preferred_authentications == NULL) 375 options.preferred_authentications = authmethods_get(); 376 377 /* setup authentication context */ 378 memset(&authctxt, 0, sizeof(authctxt)); 379 pubkey_prepare(&authctxt); 380 authctxt.server_user = server_user; 381 authctxt.local_user = local_user; 382 authctxt.host = host; 383 authctxt.service = "ssh-connection"; /* service name */ 384 authctxt.success = 0; 385 authctxt.method = authmethod_lookup("none"); 386 authctxt.authlist = NULL; 387 authctxt.methoddata = NULL; 388 authctxt.sensitive = sensitive; 389 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 390 authctxt.info_req_seen = 0; 391 authctxt.agent_fd = -1; 392 if (authctxt.method == NULL) 393 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 394 395 if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 || 396 (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 || 397 (r = sshpkt_send(ssh)) != 0) 398 fatal("%s: %s", __func__, ssh_err(r)); 399 400 ssh->authctxt = &authctxt; 401 ssh_dispatch_init(ssh, &input_userauth_error); 402 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info); 403 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept); 404 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */ 405 ssh->authctxt = NULL; 406 407 pubkey_cleanup(&authctxt); 408 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 409 410 if (!authctxt.success) 411 fatal("Authentication failed."); 412 debug("Authentication succeeded (%s).", authctxt.method->name); 413 } 414 415 /* ARGSUSED */ 416 int 417 input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh) 418 { 419 Authctxt *authctxt = ssh->authctxt; 420 int r; 421 422 if (ssh_packet_remaining(ssh) > 0) { 423 char *reply; 424 425 if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0) 426 goto out; 427 debug2("service_accept: %s", reply); 428 free(reply); 429 } else { 430 debug2("buggy server: service_accept w/o service"); 431 } 432 if ((r = sshpkt_get_end(ssh)) != 0) 433 goto out; 434 debug("SSH2_MSG_SERVICE_ACCEPT received"); 435 436 /* initial userauth request */ 437 userauth_none(authctxt); 438 439 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error); 440 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 441 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 442 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 443 r = 0; 444 out: 445 return r; 446 } 447 448 /* ARGSUSED */ 449 int 450 input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh) 451 { 452 return kex_input_ext_info(type, seqnr, ssh); 453 } 454 455 void 456 userauth(Authctxt *authctxt, char *authlist) 457 { 458 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 459 authctxt->method->cleanup(authctxt); 460 461 free(authctxt->methoddata); 462 authctxt->methoddata = NULL; 463 if (authlist == NULL) { 464 authlist = authctxt->authlist; 465 } else { 466 free(authctxt->authlist); 467 authctxt->authlist = authlist; 468 } 469 for (;;) { 470 Authmethod *method = authmethod_get(authlist); 471 if (method == NULL) 472 fatal("%s@%s: Permission denied (%s).", 473 authctxt->server_user, authctxt->host, authlist); 474 authctxt->method = method; 475 476 /* reset the per method handler */ 477 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 478 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 479 480 /* and try new method */ 481 if (method->userauth(authctxt) != 0) { 482 debug2("we sent a %s packet, wait for reply", method->name); 483 break; 484 } else { 485 debug2("we did not send a packet, disable method"); 486 method->enabled = NULL; 487 } 488 } 489 } 490 491 /* ARGSUSED */ 492 int 493 input_userauth_error(int type, u_int32_t seq, struct ssh *ssh) 494 { 495 fatal("input_userauth_error: bad message during authentication: " 496 "type %d", type); 497 return 0; 498 } 499 500 /* ARGSUSED */ 501 int 502 input_userauth_banner(int type, u_int32_t seq, struct ssh *ssh) 503 { 504 char *msg, *lang; 505 u_int len; 506 507 debug3("%s", __func__); 508 msg = packet_get_string(&len); 509 lang = packet_get_string(NULL); 510 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) 511 fmprintf(stderr, "%s", msg); 512 free(msg); 513 free(lang); 514 return 0; 515 } 516 517 /* ARGSUSED */ 518 int 519 input_userauth_success(int type, u_int32_t seq, struct ssh *ssh) 520 { 521 Authctxt *authctxt = ssh->authctxt; 522 523 if (authctxt == NULL) 524 fatal("input_userauth_success: no authentication context"); 525 free(authctxt->authlist); 526 authctxt->authlist = NULL; 527 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 528 authctxt->method->cleanup(authctxt); 529 free(authctxt->methoddata); 530 authctxt->methoddata = NULL; 531 authctxt->success = 1; /* break out */ 532 return 0; 533 } 534 535 int 536 input_userauth_success_unexpected(int type, u_int32_t seq, struct ssh *ssh) 537 { 538 Authctxt *authctxt = ssh->authctxt; 539 540 if (authctxt == NULL) 541 fatal("%s: no authentication context", __func__); 542 543 fatal("Unexpected authentication success during %s.", 544 authctxt->method->name); 545 return 0; 546 } 547 548 /* ARGSUSED */ 549 int 550 input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh) 551 { 552 Authctxt *authctxt = ssh->authctxt; 553 char *authlist = NULL; 554 int partial; 555 556 if (authctxt == NULL) 557 fatal("input_userauth_failure: no authentication context"); 558 559 authlist = packet_get_string(NULL); 560 partial = packet_get_char(); 561 packet_check_eom(); 562 563 if (partial != 0) { 564 verbose("Authenticated with partial success."); 565 /* reset state */ 566 pubkey_reset(authctxt); 567 } 568 debug("Authentications that can continue: %s", authlist); 569 570 userauth(authctxt, authlist); 571 return 0; 572 } 573 574 /* ARGSUSED */ 575 int 576 input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh) 577 { 578 Authctxt *authctxt = ssh->authctxt; 579 struct sshkey *key = NULL; 580 Identity *id = NULL; 581 Buffer b; 582 int pktype, sent = 0; 583 u_int alen, blen; 584 char *pkalg, *fp; 585 u_char *pkblob; 586 587 if (authctxt == NULL) 588 fatal("input_userauth_pk_ok: no authentication context"); 589 if (datafellows & SSH_BUG_PKOK) { 590 /* this is similar to SSH_BUG_PKAUTH */ 591 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 592 pkblob = packet_get_string(&blen); 593 buffer_init(&b); 594 buffer_append(&b, pkblob, blen); 595 pkalg = buffer_get_string(&b, &alen); 596 buffer_free(&b); 597 } else { 598 pkalg = packet_get_string(&alen); 599 pkblob = packet_get_string(&blen); 600 } 601 packet_check_eom(); 602 603 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 604 605 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 606 debug("unknown pkalg %s", pkalg); 607 goto done; 608 } 609 if ((key = key_from_blob(pkblob, blen)) == NULL) { 610 debug("no key from blob. pkalg %s", pkalg); 611 goto done; 612 } 613 if (key->type != pktype) { 614 error("input_userauth_pk_ok: type mismatch " 615 "for decoded key (received %d, expected %d)", 616 key->type, pktype); 617 goto done; 618 } 619 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 620 SSH_FP_DEFAULT)) == NULL) 621 goto done; 622 debug2("input_userauth_pk_ok: fp %s", fp); 623 free(fp); 624 625 /* 626 * search keys in the reverse order, because last candidate has been 627 * moved to the end of the queue. this also avoids confusion by 628 * duplicate keys 629 */ 630 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 631 if (key_equal(key, id->key)) { 632 sent = sign_and_send_pubkey(authctxt, id); 633 break; 634 } 635 } 636 done: 637 if (key != NULL) 638 key_free(key); 639 free(pkalg); 640 free(pkblob); 641 642 /* try another method if we did not send a packet */ 643 if (sent == 0) 644 userauth(authctxt, NULL); 645 return 0; 646 } 647 648 #ifdef GSSAPI 649 int 650 userauth_gssapi(Authctxt *authctxt) 651 { 652 Gssctxt *gssctxt = NULL; 653 static gss_OID_set gss_supported = NULL; 654 static u_int mech = 0; 655 OM_uint32 min; 656 int ok = 0; 657 658 /* Try one GSSAPI method at a time, rather than sending them all at 659 * once. */ 660 661 if (gss_supported == NULL) 662 gss_indicate_mechs(&min, &gss_supported); 663 664 /* Check to see if the mechanism is usable before we offer it */ 665 while (mech < gss_supported->count && !ok) { 666 /* My DER encoding requires length<128 */ 667 if (gss_supported->elements[mech].length < 128 && 668 ssh_gssapi_check_mechanism(&gssctxt, 669 &gss_supported->elements[mech], authctxt->host)) { 670 ok = 1; /* Mechanism works */ 671 } else { 672 mech++; 673 } 674 } 675 676 if (!ok) 677 return 0; 678 679 authctxt->methoddata=(void *)gssctxt; 680 681 packet_start(SSH2_MSG_USERAUTH_REQUEST); 682 packet_put_cstring(authctxt->server_user); 683 packet_put_cstring(authctxt->service); 684 packet_put_cstring(authctxt->method->name); 685 686 packet_put_int(1); 687 688 packet_put_int((gss_supported->elements[mech].length) + 2); 689 packet_put_char(SSH_GSS_OIDTYPE); 690 packet_put_char(gss_supported->elements[mech].length); 691 packet_put_raw(gss_supported->elements[mech].elements, 692 gss_supported->elements[mech].length); 693 694 packet_send(); 695 696 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 697 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 698 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 699 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 700 701 mech++; /* Move along to next candidate */ 702 703 return 1; 704 } 705 706 static OM_uint32 707 process_gssapi_token(struct ssh *ssh, gss_buffer_t recv_tok) 708 { 709 Authctxt *authctxt = ssh->authctxt; 710 Gssctxt *gssctxt = authctxt->methoddata; 711 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 712 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 713 gss_buffer_desc gssbuf; 714 OM_uint32 status, ms, flags; 715 Buffer b; 716 717 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 718 recv_tok, &send_tok, &flags); 719 720 if (send_tok.length > 0) { 721 if (GSS_ERROR(status)) 722 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 723 else 724 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 725 726 packet_put_string(send_tok.value, send_tok.length); 727 packet_send(); 728 gss_release_buffer(&ms, &send_tok); 729 } 730 731 if (status == GSS_S_COMPLETE) { 732 /* send either complete or MIC, depending on mechanism */ 733 if (!(flags & GSS_C_INTEG_FLAG)) { 734 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 735 packet_send(); 736 } else { 737 ssh_gssapi_buildmic(&b, authctxt->server_user, 738 authctxt->service, "gssapi-with-mic"); 739 740 gssbuf.value = buffer_ptr(&b); 741 gssbuf.length = buffer_len(&b); 742 743 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 744 745 if (!GSS_ERROR(status)) { 746 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 747 packet_put_string(mic.value, mic.length); 748 749 packet_send(); 750 } 751 752 buffer_free(&b); 753 gss_release_buffer(&ms, &mic); 754 } 755 } 756 757 return status; 758 } 759 760 /* ARGSUSED */ 761 int 762 input_gssapi_response(int type, u_int32_t plen, struct ssh *ssh) 763 { 764 Authctxt *authctxt = ssh->authctxt; 765 Gssctxt *gssctxt; 766 int oidlen; 767 char *oidv; 768 769 if (authctxt == NULL) 770 fatal("input_gssapi_response: no authentication context"); 771 gssctxt = authctxt->methoddata; 772 773 /* Setup our OID */ 774 oidv = packet_get_string(&oidlen); 775 776 if (oidlen <= 2 || 777 oidv[0] != SSH_GSS_OIDTYPE || 778 oidv[1] != oidlen - 2) { 779 free(oidv); 780 debug("Badly encoded mechanism OID received"); 781 userauth(authctxt, NULL); 782 return 0; 783 } 784 785 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 786 fatal("Server returned different OID than expected"); 787 788 packet_check_eom(); 789 790 free(oidv); 791 792 if (GSS_ERROR(process_gssapi_token(ssh, GSS_C_NO_BUFFER))) { 793 /* Start again with next method on list */ 794 debug("Trying to start again"); 795 userauth(authctxt, NULL); 796 return 0; 797 } 798 return 0; 799 } 800 801 /* ARGSUSED */ 802 int 803 input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh) 804 { 805 Authctxt *authctxt = ssh->authctxt; 806 gss_buffer_desc recv_tok; 807 OM_uint32 status; 808 u_int slen; 809 810 if (authctxt == NULL) 811 fatal("input_gssapi_response: no authentication context"); 812 813 recv_tok.value = packet_get_string(&slen); 814 recv_tok.length = slen; /* safe typecast */ 815 816 packet_check_eom(); 817 818 status = process_gssapi_token(ssh, &recv_tok); 819 820 free(recv_tok.value); 821 822 if (GSS_ERROR(status)) { 823 /* Start again with the next method in the list */ 824 userauth(authctxt, NULL); 825 return 0; 826 } 827 return 0; 828 } 829 830 /* ARGSUSED */ 831 int 832 input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh) 833 { 834 Authctxt *authctxt = ssh->authctxt; 835 Gssctxt *gssctxt; 836 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 837 gss_buffer_desc recv_tok; 838 OM_uint32 ms; 839 u_int len; 840 841 if (authctxt == NULL) 842 fatal("input_gssapi_response: no authentication context"); 843 gssctxt = authctxt->methoddata; 844 845 recv_tok.value = packet_get_string(&len); 846 recv_tok.length = len; 847 848 packet_check_eom(); 849 850 /* Stick it into GSSAPI and see what it says */ 851 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 852 &recv_tok, &send_tok, NULL); 853 854 free(recv_tok.value); 855 gss_release_buffer(&ms, &send_tok); 856 857 /* Server will be returning a failed packet after this one */ 858 return 0; 859 } 860 861 /* ARGSUSED */ 862 int 863 input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh) 864 { 865 char *msg; 866 char *lang; 867 868 /* maj */(void)packet_get_int(); 869 /* min */(void)packet_get_int(); 870 msg=packet_get_string(NULL); 871 lang=packet_get_string(NULL); 872 873 packet_check_eom(); 874 875 debug("Server GSSAPI Error:\n%s", msg); 876 free(msg); 877 free(lang); 878 return 0; 879 } 880 #endif /* GSSAPI */ 881 882 int 883 userauth_none(Authctxt *authctxt) 884 { 885 /* initial userauth request */ 886 packet_start(SSH2_MSG_USERAUTH_REQUEST); 887 packet_put_cstring(authctxt->server_user); 888 packet_put_cstring(authctxt->service); 889 packet_put_cstring(authctxt->method->name); 890 packet_send(); 891 return 1; 892 } 893 894 int 895 userauth_passwd(Authctxt *authctxt) 896 { 897 static int attempt = 0; 898 char prompt[256]; 899 char *password; 900 const char *host = options.host_key_alias ? options.host_key_alias : 901 authctxt->host; 902 903 if (attempt++ >= options.number_of_password_prompts) 904 return 0; 905 906 if (attempt != 1) 907 error("Permission denied, please try again."); 908 909 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 910 authctxt->server_user, host); 911 password = read_passphrase(prompt, 0); 912 packet_start(SSH2_MSG_USERAUTH_REQUEST); 913 packet_put_cstring(authctxt->server_user); 914 packet_put_cstring(authctxt->service); 915 packet_put_cstring(authctxt->method->name); 916 packet_put_char(0); 917 packet_put_cstring(password); 918 explicit_bzero(password, strlen(password)); 919 free(password); 920 packet_add_padding(64); 921 packet_send(); 922 923 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 924 &input_userauth_passwd_changereq); 925 926 return 1; 927 } 928 929 /* 930 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 931 */ 932 /* ARGSUSED */ 933 int 934 input_userauth_passwd_changereq(int type, u_int32_t seqnr, struct ssh *ssh) 935 { 936 Authctxt *authctxt = ssh->authctxt; 937 char *info, *lang, *password = NULL, *retype = NULL; 938 char prompt[256]; 939 const char *host; 940 941 debug2("input_userauth_passwd_changereq"); 942 943 if (authctxt == NULL) 944 fatal("input_userauth_passwd_changereq: " 945 "no authentication context"); 946 host = options.host_key_alias ? options.host_key_alias : authctxt->host; 947 948 info = packet_get_string(NULL); 949 lang = packet_get_string(NULL); 950 if (strlen(info) > 0) 951 logit("%s", info); 952 free(info); 953 free(lang); 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(1); /* additional info */ 959 snprintf(prompt, sizeof(prompt), 960 "Enter %.30s@%.128s's old password: ", 961 authctxt->server_user, host); 962 password = read_passphrase(prompt, 0); 963 packet_put_cstring(password); 964 explicit_bzero(password, strlen(password)); 965 free(password); 966 password = NULL; 967 while (password == NULL) { 968 snprintf(prompt, sizeof(prompt), 969 "Enter %.30s@%.128s's new password: ", 970 authctxt->server_user, host); 971 password = read_passphrase(prompt, RP_ALLOW_EOF); 972 if (password == NULL) { 973 /* bail out */ 974 return 0; 975 } 976 snprintf(prompt, sizeof(prompt), 977 "Retype %.30s@%.128s's new password: ", 978 authctxt->server_user, host); 979 retype = read_passphrase(prompt, 0); 980 if (strcmp(password, retype) != 0) { 981 explicit_bzero(password, strlen(password)); 982 free(password); 983 logit("Mismatch; try again, EOF to quit."); 984 password = NULL; 985 } 986 explicit_bzero(retype, strlen(retype)); 987 free(retype); 988 } 989 packet_put_cstring(password); 990 explicit_bzero(password, strlen(password)); 991 free(password); 992 packet_add_padding(64); 993 packet_send(); 994 995 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 996 &input_userauth_passwd_changereq); 997 return 0; 998 } 999 1000 static const char * 1001 key_sign_encode(const struct sshkey *key) 1002 { 1003 struct ssh *ssh = active_state; 1004 1005 if (key->type == KEY_RSA) { 1006 switch (ssh->kex->rsa_sha2) { 1007 case 256: 1008 return "rsa-sha2-256"; 1009 case 512: 1010 return "rsa-sha2-512"; 1011 } 1012 } 1013 return key_ssh_name(key); 1014 } 1015 1016 static int 1017 identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 1018 const u_char *data, size_t datalen, u_int compat) 1019 { 1020 struct sshkey *prv; 1021 int ret; 1022 1023 /* the agent supports this key */ 1024 if (id->key != NULL && id->agent_fd != -1) 1025 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 1026 data, datalen, key_sign_encode(id->key), compat); 1027 1028 /* 1029 * we have already loaded the private key or 1030 * the private key is stored in external hardware 1031 */ 1032 if (id->key != NULL && 1033 (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))) 1034 return (sshkey_sign(id->key, sigp, lenp, data, datalen, 1035 key_sign_encode(id->key), compat)); 1036 1037 /* load the private key from the file */ 1038 if ((prv = load_identity_file(id)) == NULL) 1039 return SSH_ERR_KEY_NOT_FOUND; 1040 if (id->key != NULL && !sshkey_equal_public(prv, id->key)) { 1041 error("%s: private key %s contents do not match public", 1042 __func__, id->filename); 1043 return SSH_ERR_KEY_NOT_FOUND; 1044 } 1045 ret = sshkey_sign(prv, sigp, lenp, data, datalen, 1046 key_sign_encode(prv), compat); 1047 sshkey_free(prv); 1048 return (ret); 1049 } 1050 1051 static int 1052 id_filename_matches(Identity *id, Identity *private_id) 1053 { 1054 const char *suffixes[] = { ".pub", "-cert.pub", NULL }; 1055 size_t len = strlen(id->filename), plen = strlen(private_id->filename); 1056 size_t i, slen; 1057 1058 if (strcmp(id->filename, private_id->filename) == 0) 1059 return 1; 1060 for (i = 0; suffixes[i]; i++) { 1061 slen = strlen(suffixes[i]); 1062 if (len > slen && plen == len - slen && 1063 strcmp(id->filename + (len - slen), suffixes[i]) == 0 && 1064 memcmp(id->filename, private_id->filename, plen) == 0) 1065 return 1; 1066 } 1067 return 0; 1068 } 1069 1070 static int 1071 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1072 { 1073 Buffer b; 1074 Identity *private_id; 1075 u_char *blob, *signature; 1076 size_t slen; 1077 u_int bloblen, skip = 0; 1078 int matched, ret = -1, have_sig = 1; 1079 char *fp; 1080 1081 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1082 SSH_FP_DEFAULT)) == NULL) 1083 return 0; 1084 debug3("%s: %s %s", __func__, key_type(id->key), fp); 1085 free(fp); 1086 1087 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1088 /* we cannot handle this key */ 1089 debug3("sign_and_send_pubkey: cannot handle key"); 1090 return 0; 1091 } 1092 /* data to be signed */ 1093 buffer_init(&b); 1094 if (datafellows & SSH_OLD_SESSIONID) { 1095 buffer_append(&b, session_id2, session_id2_len); 1096 skip = session_id2_len; 1097 } else { 1098 buffer_put_string(&b, session_id2, session_id2_len); 1099 skip = buffer_len(&b); 1100 } 1101 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1102 buffer_put_cstring(&b, authctxt->server_user); 1103 buffer_put_cstring(&b, 1104 datafellows & SSH_BUG_PKSERVICE ? 1105 "ssh-userauth" : 1106 authctxt->service); 1107 if (datafellows & SSH_BUG_PKAUTH) { 1108 buffer_put_char(&b, have_sig); 1109 } else { 1110 buffer_put_cstring(&b, authctxt->method->name); 1111 buffer_put_char(&b, have_sig); 1112 buffer_put_cstring(&b, key_sign_encode(id->key)); 1113 } 1114 buffer_put_string(&b, blob, bloblen); 1115 1116 /* 1117 * If the key is an certificate, try to find a matching private key 1118 * and use it to complete the signature. 1119 * If no such private key exists, fall back to trying the certificate 1120 * key itself in case it has a private half already loaded. 1121 */ 1122 if (key_is_cert(id->key)) { 1123 matched = 0; 1124 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1125 if (sshkey_equal_public(id->key, private_id->key) && 1126 id->key->type != private_id->key->type) { 1127 id = private_id; 1128 matched = 1; 1129 break; 1130 } 1131 } 1132 /* 1133 * Exact key matches are preferred, but also allow 1134 * filename matches for non-PKCS#11/agent keys that 1135 * didn't load public keys. This supports the case 1136 * of keeping just a private key file and public 1137 * certificate on disk. 1138 */ 1139 if (!matched && !id->isprivate && id->agent_fd == -1 && 1140 (id->key->flags & SSHKEY_FLAG_EXT) == 0) { 1141 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1142 if (private_id->key == NULL && 1143 id_filename_matches(id, private_id)) { 1144 id = private_id; 1145 matched = 1; 1146 break; 1147 } 1148 } 1149 } 1150 if (matched) { 1151 debug2("%s: using private key \"%s\"%s for " 1152 "certificate", __func__, id->filename, 1153 id->agent_fd != -1 ? " from agent" : ""); 1154 } else { 1155 debug("%s: no separate private key for certificate " 1156 "\"%s\"", __func__, id->filename); 1157 } 1158 } 1159 1160 /* generate signature */ 1161 ret = identity_sign(id, &signature, &slen, 1162 buffer_ptr(&b), buffer_len(&b), datafellows); 1163 if (ret != 0) { 1164 if (ret != SSH_ERR_KEY_NOT_FOUND) 1165 error("%s: signing failed: %s", __func__, ssh_err(ret)); 1166 free(blob); 1167 buffer_free(&b); 1168 return 0; 1169 } 1170 #ifdef DEBUG_PK 1171 buffer_dump(&b); 1172 #endif 1173 if (datafellows & SSH_BUG_PKSERVICE) { 1174 buffer_clear(&b); 1175 buffer_append(&b, session_id2, session_id2_len); 1176 skip = session_id2_len; 1177 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1178 buffer_put_cstring(&b, authctxt->server_user); 1179 buffer_put_cstring(&b, authctxt->service); 1180 buffer_put_cstring(&b, authctxt->method->name); 1181 buffer_put_char(&b, have_sig); 1182 if (!(datafellows & SSH_BUG_PKAUTH)) 1183 buffer_put_cstring(&b, key_ssh_name(id->key)); 1184 buffer_put_string(&b, blob, bloblen); 1185 } 1186 free(blob); 1187 1188 /* append signature */ 1189 buffer_put_string(&b, signature, slen); 1190 free(signature); 1191 1192 /* skip session id and packet type */ 1193 if (buffer_len(&b) < skip + 1) 1194 fatal("userauth_pubkey: internal error"); 1195 buffer_consume(&b, skip + 1); 1196 1197 /* put remaining data from buffer into packet */ 1198 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1199 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1200 buffer_free(&b); 1201 packet_send(); 1202 1203 return 1; 1204 } 1205 1206 static int 1207 send_pubkey_test(Authctxt *authctxt, Identity *id) 1208 { 1209 u_char *blob; 1210 u_int bloblen, have_sig = 0; 1211 1212 debug3("send_pubkey_test"); 1213 1214 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1215 /* we cannot handle this key */ 1216 debug3("send_pubkey_test: cannot handle key"); 1217 return 0; 1218 } 1219 /* register callback for USERAUTH_PK_OK message */ 1220 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1221 1222 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1223 packet_put_cstring(authctxt->server_user); 1224 packet_put_cstring(authctxt->service); 1225 packet_put_cstring(authctxt->method->name); 1226 packet_put_char(have_sig); 1227 if (!(datafellows & SSH_BUG_PKAUTH)) 1228 packet_put_cstring(key_sign_encode(id->key)); 1229 packet_put_string(blob, bloblen); 1230 free(blob); 1231 packet_send(); 1232 return 1; 1233 } 1234 1235 static struct sshkey * 1236 load_identity_file(Identity *id) 1237 { 1238 struct sshkey *private = NULL; 1239 char prompt[300], *passphrase, *comment; 1240 int r, perm_ok = 0, quit = 0, i; 1241 struct stat st; 1242 1243 if (stat(id->filename, &st) < 0) { 1244 (id->userprovided ? logit : debug3)("no such identity: %s: %s", 1245 id->filename, strerror(errno)); 1246 return NULL; 1247 } 1248 snprintf(prompt, sizeof prompt, 1249 "Enter passphrase for key '%.100s': ", id->filename); 1250 for (i = 0; i <= options.number_of_password_prompts; i++) { 1251 if (i == 0) 1252 passphrase = ""; 1253 else { 1254 passphrase = read_passphrase(prompt, 0); 1255 if (*passphrase == '\0') { 1256 debug2("no passphrase given, try next key"); 1257 free(passphrase); 1258 break; 1259 } 1260 } 1261 switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename, 1262 passphrase, &private, &comment, &perm_ok))) { 1263 case 0: 1264 break; 1265 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1266 if (options.batch_mode) { 1267 quit = 1; 1268 break; 1269 } 1270 if (i != 0) 1271 debug2("bad passphrase given, try again..."); 1272 break; 1273 case SSH_ERR_SYSTEM_ERROR: 1274 if (errno == ENOENT) { 1275 debug2("Load key \"%s\": %s", 1276 id->filename, ssh_err(r)); 1277 quit = 1; 1278 break; 1279 } 1280 /* FALLTHROUGH */ 1281 default: 1282 error("Load key \"%s\": %s", id->filename, ssh_err(r)); 1283 quit = 1; 1284 break; 1285 } 1286 if (!quit && private != NULL && id->agent_fd == -1 && 1287 !(id->key && id->isprivate)) 1288 maybe_add_key_to_agent(id->filename, private, comment, 1289 passphrase); 1290 if (i > 0) { 1291 explicit_bzero(passphrase, strlen(passphrase)); 1292 free(passphrase); 1293 } 1294 free(comment); 1295 if (private != NULL || quit) 1296 break; 1297 } 1298 return private; 1299 } 1300 1301 /* 1302 * try keys in the following order: 1303 * 1. certificates listed in the config file 1304 * 2. other input certificates 1305 * 3. agent keys that are found in the config file 1306 * 4. other agent keys 1307 * 5. keys that are only listed in the config file 1308 */ 1309 static void 1310 pubkey_prepare(Authctxt *authctxt) 1311 { 1312 struct identity *id, *id2, *tmp; 1313 struct idlist agent, files, *preferred; 1314 struct sshkey *key; 1315 int agent_fd = -1, i, r, found; 1316 size_t j; 1317 struct ssh_identitylist *idlist; 1318 1319 TAILQ_INIT(&agent); /* keys from the agent */ 1320 TAILQ_INIT(&files); /* keys from the config file */ 1321 preferred = &authctxt->keys; 1322 TAILQ_INIT(preferred); /* preferred order of keys */ 1323 1324 /* list of keys stored in the filesystem and PKCS#11 */ 1325 for (i = 0; i < options.num_identity_files; i++) { 1326 key = options.identity_keys[i]; 1327 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1328 continue; 1329 options.identity_keys[i] = NULL; 1330 id = xcalloc(1, sizeof(*id)); 1331 id->agent_fd = -1; 1332 id->key = key; 1333 id->filename = xstrdup(options.identity_files[i]); 1334 id->userprovided = options.identity_file_userprovided[i]; 1335 TAILQ_INSERT_TAIL(&files, id, next); 1336 } 1337 /* list of certificates specified by user */ 1338 for (i = 0; i < options.num_certificate_files; i++) { 1339 key = options.certificates[i]; 1340 if (!key_is_cert(key) || key->cert == NULL || 1341 key->cert->type != SSH2_CERT_TYPE_USER) 1342 continue; 1343 id = xcalloc(1, sizeof(*id)); 1344 id->agent_fd = -1; 1345 id->key = key; 1346 id->filename = xstrdup(options.certificate_files[i]); 1347 id->userprovided = options.certificate_file_userprovided[i]; 1348 TAILQ_INSERT_TAIL(preferred, id, next); 1349 } 1350 /* list of keys supported by the agent */ 1351 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1352 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1353 debug("%s: ssh_get_authentication_socket: %s", 1354 __func__, ssh_err(r)); 1355 } else if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 1356 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1357 debug("%s: ssh_fetch_identitylist: %s", 1358 __func__, ssh_err(r)); 1359 close(agent_fd); 1360 } else { 1361 for (j = 0; j < idlist->nkeys; j++) { 1362 found = 0; 1363 TAILQ_FOREACH(id, &files, next) { 1364 /* 1365 * agent keys from the config file are 1366 * preferred 1367 */ 1368 if (sshkey_equal(idlist->keys[j], id->key)) { 1369 TAILQ_REMOVE(&files, id, next); 1370 TAILQ_INSERT_TAIL(preferred, id, next); 1371 id->agent_fd = agent_fd; 1372 found = 1; 1373 break; 1374 } 1375 } 1376 if (!found && !options.identities_only) { 1377 id = xcalloc(1, sizeof(*id)); 1378 /* XXX "steals" key/comment from idlist */ 1379 id->key = idlist->keys[j]; 1380 id->filename = idlist->comments[j]; 1381 idlist->keys[j] = NULL; 1382 idlist->comments[j] = NULL; 1383 id->agent_fd = agent_fd; 1384 TAILQ_INSERT_TAIL(&agent, id, next); 1385 } 1386 } 1387 ssh_free_identitylist(idlist); 1388 /* append remaining agent keys */ 1389 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1390 TAILQ_REMOVE(&agent, id, next); 1391 TAILQ_INSERT_TAIL(preferred, id, next); 1392 } 1393 authctxt->agent_fd = agent_fd; 1394 } 1395 /* Prefer PKCS11 keys that are explicitly listed */ 1396 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1397 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1398 continue; 1399 found = 0; 1400 TAILQ_FOREACH(id2, &files, next) { 1401 if (id2->key == NULL || 1402 (id2->key->flags & SSHKEY_FLAG_EXT) == 0) 1403 continue; 1404 if (sshkey_equal(id->key, id2->key)) { 1405 TAILQ_REMOVE(&files, id, next); 1406 TAILQ_INSERT_TAIL(preferred, id, next); 1407 found = 1; 1408 break; 1409 } 1410 } 1411 /* If IdentitiesOnly set and key not found then don't use it */ 1412 if (!found && options.identities_only) { 1413 TAILQ_REMOVE(&files, id, next); 1414 explicit_bzero(id, sizeof(*id)); 1415 free(id); 1416 } 1417 } 1418 /* append remaining keys from the config file */ 1419 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1420 TAILQ_REMOVE(&files, id, next); 1421 TAILQ_INSERT_TAIL(preferred, id, next); 1422 } 1423 /* finally, filter by PubkeyAcceptedKeyTypes */ 1424 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1425 if (id->key != NULL && 1426 match_pattern_list(sshkey_ssh_name(id->key), 1427 options.pubkey_key_types, 0) != 1) { 1428 debug("Skipping %s key %s - " 1429 "not in PubkeyAcceptedKeyTypes", 1430 sshkey_ssh_name(id->key), id->filename); 1431 TAILQ_REMOVE(preferred, id, next); 1432 sshkey_free(id->key); 1433 free(id->filename); 1434 memset(id, 0, sizeof(*id)); 1435 continue; 1436 } 1437 debug2("key: %s (%p)%s%s", id->filename, id->key, 1438 id->userprovided ? ", explicit" : "", 1439 id->agent_fd != -1 ? ", agent" : ""); 1440 } 1441 } 1442 1443 static void 1444 pubkey_cleanup(Authctxt *authctxt) 1445 { 1446 Identity *id; 1447 1448 if (authctxt->agent_fd != -1) 1449 ssh_close_authentication_socket(authctxt->agent_fd); 1450 for (id = TAILQ_FIRST(&authctxt->keys); id; 1451 id = TAILQ_FIRST(&authctxt->keys)) { 1452 TAILQ_REMOVE(&authctxt->keys, id, next); 1453 sshkey_free(id->key); 1454 free(id->filename); 1455 free(id); 1456 } 1457 } 1458 1459 static void 1460 pubkey_reset(Authctxt *authctxt) 1461 { 1462 Identity *id; 1463 1464 TAILQ_FOREACH(id, &authctxt->keys, next) 1465 id->tried = 0; 1466 } 1467 1468 static int 1469 try_identity(Identity *id) 1470 { 1471 if (!id->key) 1472 return (0); 1473 if (key_type_plain(id->key->type) == KEY_RSA && 1474 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1475 debug("Skipped %s key %s for RSA/MD5 server", 1476 key_type(id->key), id->filename); 1477 return (0); 1478 } 1479 return 1; 1480 } 1481 1482 int 1483 userauth_pubkey(Authctxt *authctxt) 1484 { 1485 Identity *id; 1486 int sent = 0; 1487 char *fp; 1488 1489 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1490 if (id->tried++) 1491 return (0); 1492 /* move key to the end of the queue */ 1493 TAILQ_REMOVE(&authctxt->keys, id, next); 1494 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1495 /* 1496 * send a test message if we have the public key. for 1497 * encrypted keys we cannot do this and have to load the 1498 * private key instead 1499 */ 1500 if (id->key != NULL) { 1501 if (try_identity(id)) { 1502 if ((fp = sshkey_fingerprint(id->key, 1503 options.fingerprint_hash, 1504 SSH_FP_DEFAULT)) == NULL) { 1505 error("%s: sshkey_fingerprint failed", 1506 __func__); 1507 return 0; 1508 } 1509 debug("Offering public key: %s %s %s", 1510 sshkey_type(id->key), fp, id->filename); 1511 free(fp); 1512 sent = send_pubkey_test(authctxt, id); 1513 } 1514 } else { 1515 debug("Trying private key: %s", id->filename); 1516 id->key = load_identity_file(id); 1517 if (id->key != NULL) { 1518 if (try_identity(id)) { 1519 id->isprivate = 1; 1520 sent = sign_and_send_pubkey( 1521 authctxt, id); 1522 } 1523 key_free(id->key); 1524 id->key = NULL; 1525 id->isprivate = 0; 1526 } 1527 } 1528 if (sent) 1529 return (sent); 1530 } 1531 return (0); 1532 } 1533 1534 /* 1535 * Send userauth request message specifying keyboard-interactive method. 1536 */ 1537 int 1538 userauth_kbdint(Authctxt *authctxt) 1539 { 1540 static int attempt = 0; 1541 1542 if (attempt++ >= options.number_of_password_prompts) 1543 return 0; 1544 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1545 if (attempt > 1 && !authctxt->info_req_seen) { 1546 debug3("userauth_kbdint: disable: no info_req_seen"); 1547 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1548 return 0; 1549 } 1550 1551 debug2("userauth_kbdint"); 1552 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1553 packet_put_cstring(authctxt->server_user); 1554 packet_put_cstring(authctxt->service); 1555 packet_put_cstring(authctxt->method->name); 1556 packet_put_cstring(""); /* lang */ 1557 packet_put_cstring(options.kbd_interactive_devices ? 1558 options.kbd_interactive_devices : ""); 1559 packet_send(); 1560 1561 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1562 return 1; 1563 } 1564 1565 /* 1566 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1567 */ 1568 int 1569 input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh) 1570 { 1571 Authctxt *authctxt = ssh->authctxt; 1572 char *name, *inst, *lang, *prompt, *response; 1573 u_int num_prompts, i; 1574 int echo = 0; 1575 1576 debug2("input_userauth_info_req"); 1577 1578 if (authctxt == NULL) 1579 fatal("input_userauth_info_req: no authentication context"); 1580 1581 authctxt->info_req_seen = 1; 1582 1583 name = packet_get_string(NULL); 1584 inst = packet_get_string(NULL); 1585 lang = packet_get_string(NULL); 1586 if (strlen(name) > 0) 1587 logit("%s", name); 1588 if (strlen(inst) > 0) 1589 logit("%s", inst); 1590 free(name); 1591 free(inst); 1592 free(lang); 1593 1594 num_prompts = packet_get_int(); 1595 /* 1596 * Begin to build info response packet based on prompts requested. 1597 * We commit to providing the correct number of responses, so if 1598 * further on we run into a problem that prevents this, we have to 1599 * be sure and clean this up and send a correct error response. 1600 */ 1601 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1602 packet_put_int(num_prompts); 1603 1604 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1605 for (i = 0; i < num_prompts; i++) { 1606 prompt = packet_get_string(NULL); 1607 echo = packet_get_char(); 1608 1609 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1610 1611 packet_put_cstring(response); 1612 explicit_bzero(response, strlen(response)); 1613 free(response); 1614 free(prompt); 1615 } 1616 packet_check_eom(); /* done with parsing incoming message. */ 1617 1618 packet_add_padding(64); 1619 packet_send(); 1620 return 0; 1621 } 1622 1623 static int 1624 ssh_keysign(struct sshkey *key, u_char **sigp, size_t *lenp, 1625 const u_char *data, size_t datalen) 1626 { 1627 struct sshbuf *b; 1628 struct stat st; 1629 pid_t pid; 1630 int i, r, to[2], from[2], status, sock = packet_get_connection_in(); 1631 u_char rversion = 0, version = 2; 1632 void (*osigchld)(int); 1633 1634 *sigp = NULL; 1635 *lenp = 0; 1636 1637 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1638 error("%s: not installed: %s", __func__, strerror(errno)); 1639 return -1; 1640 } 1641 if (fflush(stdout) != 0) { 1642 error("%s: fflush: %s", __func__, strerror(errno)); 1643 return -1; 1644 } 1645 if (pipe(to) < 0) { 1646 error("%s: pipe: %s", __func__, strerror(errno)); 1647 return -1; 1648 } 1649 if (pipe(from) < 0) { 1650 error("%s: pipe: %s", __func__, strerror(errno)); 1651 return -1; 1652 } 1653 if ((pid = fork()) < 0) { 1654 error("%s: fork: %s", __func__, strerror(errno)); 1655 return -1; 1656 } 1657 osigchld = signal(SIGCHLD, SIG_DFL); 1658 if (pid == 0) { 1659 /* keep the socket on exec */ 1660 fcntl(sock, F_SETFD, 0); 1661 permanently_drop_suid(getuid()); 1662 close(from[0]); 1663 if (dup2(from[1], STDOUT_FILENO) < 0) 1664 fatal("%s: dup2: %s", __func__, strerror(errno)); 1665 close(to[1]); 1666 if (dup2(to[0], STDIN_FILENO) < 0) 1667 fatal("%s: dup2: %s", __func__, strerror(errno)); 1668 close(from[1]); 1669 close(to[0]); 1670 /* Close everything but stdio and the socket */ 1671 for (i = STDERR_FILENO + 1; i < sock; i++) 1672 close(i); 1673 closefrom(sock + 1); 1674 debug3("%s: [child] pid=%ld, exec %s", 1675 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1676 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL); 1677 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1678 strerror(errno)); 1679 } 1680 close(from[1]); 1681 close(to[0]); 1682 1683 if ((b = sshbuf_new()) == NULL) 1684 fatal("%s: sshbuf_new failed", __func__); 1685 /* send # of sock, data to be signed */ 1686 if ((r = sshbuf_put_u32(b, sock)) != 0 || 1687 (r = sshbuf_put_string(b, data, datalen)) != 0) 1688 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1689 if (ssh_msg_send(to[1], version, b) == -1) 1690 fatal("%s: couldn't send request", __func__); 1691 sshbuf_reset(b); 1692 r = ssh_msg_recv(from[0], b); 1693 close(from[0]); 1694 close(to[1]); 1695 if (r < 0) { 1696 error("%s: no reply", __func__); 1697 goto fail; 1698 } 1699 1700 errno = 0; 1701 while (waitpid(pid, &status, 0) < 0) { 1702 if (errno != EINTR) { 1703 error("%s: waitpid %ld: %s", 1704 __func__, (long)pid, strerror(errno)); 1705 goto fail; 1706 } 1707 } 1708 if (!WIFEXITED(status)) { 1709 error("%s: exited abnormally", __func__); 1710 goto fail; 1711 } 1712 if (WEXITSTATUS(status) != 0) { 1713 error("%s: exited with status %d", 1714 __func__, WEXITSTATUS(status)); 1715 goto fail; 1716 } 1717 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 1718 error("%s: buffer error: %s", __func__, ssh_err(r)); 1719 goto fail; 1720 } 1721 if (rversion != version) { 1722 error("%s: bad version", __func__); 1723 goto fail; 1724 } 1725 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 1726 error("%s: buffer error: %s", __func__, ssh_err(r)); 1727 fail: 1728 signal(SIGCHLD, osigchld); 1729 sshbuf_free(b); 1730 return -1; 1731 } 1732 signal(SIGCHLD, osigchld); 1733 sshbuf_free(b); 1734 1735 return 0; 1736 } 1737 1738 int 1739 userauth_hostbased(Authctxt *authctxt) 1740 { 1741 struct ssh *ssh = active_state; 1742 struct sshkey *private = NULL; 1743 struct sshbuf *b = NULL; 1744 const char *service; 1745 u_char *sig = NULL, *keyblob = NULL; 1746 char *fp = NULL, *chost = NULL, *lname = NULL; 1747 size_t siglen = 0, keylen = 0; 1748 int i, r, success = 0; 1749 1750 if (authctxt->ktypes == NULL) { 1751 authctxt->oktypes = xstrdup(options.hostbased_key_types); 1752 authctxt->ktypes = authctxt->oktypes; 1753 } 1754 1755 /* 1756 * Work through each listed type pattern in HostbasedKeyTypes, 1757 * trying each hostkey that matches the type in turn. 1758 */ 1759 for (;;) { 1760 if (authctxt->active_ktype == NULL) 1761 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 1762 if (authctxt->active_ktype == NULL || 1763 *authctxt->active_ktype == '\0') 1764 break; 1765 debug3("%s: trying key type %s", __func__, 1766 authctxt->active_ktype); 1767 1768 /* check for a useful key */ 1769 private = NULL; 1770 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 1771 if (authctxt->sensitive->keys[i] == NULL || 1772 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 1773 continue; 1774 if (match_pattern_list( 1775 sshkey_ssh_name(authctxt->sensitive->keys[i]), 1776 authctxt->active_ktype, 0) != 1) 1777 continue; 1778 /* we take and free the key */ 1779 private = authctxt->sensitive->keys[i]; 1780 authctxt->sensitive->keys[i] = NULL; 1781 break; 1782 } 1783 /* Found one */ 1784 if (private != NULL) 1785 break; 1786 /* No more keys of this type; advance */ 1787 authctxt->active_ktype = NULL; 1788 } 1789 if (private == NULL) { 1790 free(authctxt->oktypes); 1791 authctxt->oktypes = authctxt->ktypes = NULL; 1792 authctxt->active_ktype = NULL; 1793 debug("No more client hostkeys for hostbased authentication."); 1794 goto out; 1795 } 1796 1797 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 1798 SSH_FP_DEFAULT)) == NULL) { 1799 error("%s: sshkey_fingerprint failed", __func__); 1800 goto out; 1801 } 1802 debug("%s: trying hostkey %s %s", 1803 __func__, sshkey_ssh_name(private), fp); 1804 1805 /* figure out a name for the client host */ 1806 if ((lname = get_local_name(packet_get_connection_in())) == NULL) { 1807 error("%s: cannot get local ipaddr/name", __func__); 1808 goto out; 1809 } 1810 1811 /* XXX sshbuf_put_stringf? */ 1812 xasprintf(&chost, "%s.", lname); 1813 debug2("%s: chost %s", __func__, chost); 1814 1815 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1816 authctxt->service; 1817 1818 /* construct data */ 1819 if ((b = sshbuf_new()) == NULL) { 1820 error("%s: sshbuf_new failed", __func__); 1821 goto out; 1822 } 1823 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 1824 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 1825 goto out; 1826 } 1827 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 1828 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1829 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1830 (r = sshbuf_put_cstring(b, service)) != 0 || 1831 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1832 (r = sshbuf_put_cstring(b, key_ssh_name(private))) != 0 || 1833 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 1834 (r = sshbuf_put_cstring(b, chost)) != 0 || 1835 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 1836 error("%s: buffer error: %s", __func__, ssh_err(r)); 1837 goto out; 1838 } 1839 1840 #ifdef DEBUG_PK 1841 sshbuf_dump(b, stderr); 1842 #endif 1843 if (authctxt->sensitive->external_keysign) 1844 r = ssh_keysign(private, &sig, &siglen, 1845 sshbuf_ptr(b), sshbuf_len(b)); 1846 else if ((r = sshkey_sign(private, &sig, &siglen, 1847 sshbuf_ptr(b), sshbuf_len(b), NULL, datafellows)) != 0) 1848 debug("%s: sshkey_sign: %s", __func__, ssh_err(r)); 1849 if (r != 0) { 1850 error("sign using hostkey %s %s failed", 1851 sshkey_ssh_name(private), fp); 1852 goto out; 1853 } 1854 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1855 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1856 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1857 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1858 (r = sshpkt_put_cstring(ssh, key_ssh_name(private))) != 0 || 1859 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 1860 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 1861 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 1862 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 1863 (r = sshpkt_send(ssh)) != 0) { 1864 error("%s: packet error: %s", __func__, ssh_err(r)); 1865 goto out; 1866 } 1867 success = 1; 1868 1869 out: 1870 if (sig != NULL) { 1871 explicit_bzero(sig, siglen); 1872 free(sig); 1873 } 1874 free(keyblob); 1875 free(lname); 1876 free(fp); 1877 free(chost); 1878 sshkey_free(private); 1879 sshbuf_free(b); 1880 1881 return success; 1882 } 1883 1884 /* find auth method */ 1885 1886 /* 1887 * given auth method name, if configurable options permit this method fill 1888 * in auth_ident field and return true, otherwise return false. 1889 */ 1890 static int 1891 authmethod_is_enabled(Authmethod *method) 1892 { 1893 if (method == NULL) 1894 return 0; 1895 /* return false if options indicate this method is disabled */ 1896 if (method->enabled == NULL || *method->enabled == 0) 1897 return 0; 1898 /* return false if batch mode is enabled but method needs interactive mode */ 1899 if (method->batch_flag != NULL && *method->batch_flag != 0) 1900 return 0; 1901 return 1; 1902 } 1903 1904 static Authmethod * 1905 authmethod_lookup(const char *name) 1906 { 1907 Authmethod *method = NULL; 1908 if (name != NULL) 1909 for (method = authmethods; method->name != NULL; method++) 1910 if (strcmp(name, method->name) == 0) 1911 return method; 1912 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1913 return NULL; 1914 } 1915 1916 /* XXX internal state */ 1917 static Authmethod *current = NULL; 1918 static char *supported = NULL; 1919 static char *preferred = NULL; 1920 1921 /* 1922 * Given the authentication method list sent by the server, return the 1923 * next method we should try. If the server initially sends a nil list, 1924 * use a built-in default list. 1925 */ 1926 static Authmethod * 1927 authmethod_get(char *authlist) 1928 { 1929 char *name = NULL; 1930 u_int next; 1931 1932 /* Use a suitable default if we're passed a nil list. */ 1933 if (authlist == NULL || strlen(authlist) == 0) 1934 authlist = options.preferred_authentications; 1935 1936 if (supported == NULL || strcmp(authlist, supported) != 0) { 1937 debug3("start over, passed a different list %s", authlist); 1938 free(supported); 1939 supported = xstrdup(authlist); 1940 preferred = options.preferred_authentications; 1941 debug3("preferred %s", preferred); 1942 current = NULL; 1943 } else if (current != NULL && authmethod_is_enabled(current)) 1944 return current; 1945 1946 for (;;) { 1947 if ((name = match_list(preferred, supported, &next)) == NULL) { 1948 debug("No more authentication methods to try."); 1949 current = NULL; 1950 return NULL; 1951 } 1952 preferred += next; 1953 debug3("authmethod_lookup %s", name); 1954 debug3("remaining preferred: %s", preferred); 1955 if ((current = authmethod_lookup(name)) != NULL && 1956 authmethod_is_enabled(current)) { 1957 debug3("authmethod_is_enabled %s", name); 1958 debug("Next authentication method: %s", name); 1959 free(name); 1960 return current; 1961 } 1962 free(name); 1963 } 1964 } 1965 1966 static char * 1967 authmethods_get(void) 1968 { 1969 Authmethod *method = NULL; 1970 Buffer b; 1971 char *list; 1972 1973 buffer_init(&b); 1974 for (method = authmethods; method->name != NULL; method++) { 1975 if (authmethod_is_enabled(method)) { 1976 if (buffer_len(&b) > 0) 1977 buffer_append(&b, ",", 1); 1978 buffer_append(&b, method->name, strlen(method->name)); 1979 } 1980 } 1981 if ((list = sshbuf_dup_string(&b)) == NULL) 1982 fatal("%s: sshbuf_dup_string failed", __func__); 1983 buffer_free(&b); 1984 return list; 1985 } 1986 1987