1/* $OpenBSD: sshconnect2.c,v 1.288 2018/10/11 03:48:04 djm Exp $ */ 2/* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27#include "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 "sshbuf.h" 53#include "packet.h" 54#include "compat.h" 55#include "cipher.h" 56#include "sshkey.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 */ 81extern char *client_version_string; 82extern char *server_version_string; 83extern Options options; 84 85/* 86 * SSH2 key exchange 87 */ 88 89u_char *session_id2 = NULL; 90u_int session_id2_len = 0; 91 92char *xxx_host; 93struct sockaddr *xxx_hostaddr; 94 95static int 96verify_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 103static char * 104order_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 157void 158ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 159{ 160 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; 161 char *s, *all_key; 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 all_key = sshkey_alg_list(0, 0, 1, ','); 182 if (kex_assemble_names(&options.hostkeyalgorithms, 183 KEX_DEFAULT_PK_ALG, all_key) != 0) 184 fatal("%s: kex_assemble_namelist", __func__); 185 free(all_key); 186 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 187 compat_pkalg_proposal(options.hostkeyalgorithms); 188 } else { 189 /* Enforce default */ 190 options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG); 191 /* Prefer algorithms that we already have keys for */ 192 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 193 compat_pkalg_proposal( 194 order_hostkeyalgs(host, hostaddr, port)); 195 } 196 197 if (options.rekey_limit || options.rekey_interval) 198 packet_set_rekey_limits(options.rekey_limit, 199 options.rekey_interval); 200 201 /* start key exchange */ 202 if ((r = kex_setup(active_state, myproposal)) != 0) 203 fatal("kex_setup: %s", ssh_err(r)); 204 kex = active_state->kex; 205#ifdef WITH_OPENSSL 206 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 207 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 208 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client; 209 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client; 210 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client; 211 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 212 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 213# ifdef OPENSSL_HAS_ECC 214 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 215# endif 216#endif 217 kex->kex[KEX_C25519_SHA256] = kexc25519_client; 218 kex->client_version_string=client_version_string; 219 kex->server_version_string=server_version_string; 220 kex->verify_host_key=&verify_host_key_callback; 221 222 ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done); 223 224 /* remove ext-info from the KEX proposals for rekeying */ 225 myproposal[PROPOSAL_KEX_ALGS] = 226 compat_kex_proposal(options.kex_algorithms); 227 if ((r = kex_prop2buf(kex->my, myproposal)) != 0) 228 fatal("kex_prop2buf: %s", ssh_err(r)); 229 230 session_id2 = kex->session_id; 231 session_id2_len = kex->session_id_len; 232 233#ifdef DEBUG_KEXDH 234 /* send 1st encrypted/maced/compressed message */ 235 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 236 (r = sshpkt_put_cstring(ssh, "markus")) != 0 || 237 (r = sshpkt_send(ssh)) != 0 || 238 (r = ssh_packet_write_wait(ssh)) != 0) 239 fatal("%s: %s", __func__, ssh_err(r)); 240#endif 241} 242 243/* 244 * Authenticate user 245 */ 246 247typedef struct cauthctxt Authctxt; 248typedef struct cauthmethod Authmethod; 249typedef struct identity Identity; 250typedef struct idlist Idlist; 251 252struct identity { 253 TAILQ_ENTRY(identity) next; 254 int agent_fd; /* >=0 if agent supports key */ 255 struct sshkey *key; /* public/private key */ 256 char *filename; /* comment for agent-only keys */ 257 int tried; 258 int isprivate; /* key points to the private key */ 259 int userprovided; 260}; 261TAILQ_HEAD(idlist, identity); 262 263struct cauthctxt { 264 const char *server_user; 265 const char *local_user; 266 const char *host; 267 const char *service; 268 struct cauthmethod *method; 269 sig_atomic_t success; 270 char *authlist; 271 int attempt; 272 /* pubkey */ 273 struct idlist keys; 274 int agent_fd; 275 /* hostbased */ 276 Sensitive *sensitive; 277 char *oktypes, *ktypes; 278 const char *active_ktype; 279 /* kbd-interactive */ 280 int info_req_seen; 281 /* generic */ 282 void *methoddata; 283}; 284 285struct cauthmethod { 286 char *name; /* string to compare against server's list */ 287 int (*userauth)(Authctxt *authctxt); 288 void (*cleanup)(Authctxt *authctxt); 289 int *enabled; /* flag in option struct that enables method */ 290 int *batch_flag; /* flag in option struct that disables method */ 291}; 292 293int input_userauth_service_accept(int, u_int32_t, struct ssh *); 294int input_userauth_ext_info(int, u_int32_t, struct ssh *); 295int input_userauth_success(int, u_int32_t, struct ssh *); 296int input_userauth_success_unexpected(int, u_int32_t, struct ssh *); 297int input_userauth_failure(int, u_int32_t, struct ssh *); 298int input_userauth_banner(int, u_int32_t, struct ssh *); 299int input_userauth_error(int, u_int32_t, struct ssh *); 300int input_userauth_info_req(int, u_int32_t, struct ssh *); 301int input_userauth_pk_ok(int, u_int32_t, struct ssh *); 302int input_userauth_passwd_changereq(int, u_int32_t, struct ssh *); 303 304int userauth_none(Authctxt *); 305int userauth_pubkey(Authctxt *); 306int userauth_passwd(Authctxt *); 307int userauth_kbdint(Authctxt *); 308int userauth_hostbased(Authctxt *); 309 310#ifdef GSSAPI 311int userauth_gssapi(Authctxt *authctxt); 312int input_gssapi_response(int type, u_int32_t, struct ssh *); 313int input_gssapi_token(int type, u_int32_t, struct ssh *); 314int input_gssapi_hash(int type, u_int32_t, struct ssh *); 315int input_gssapi_error(int, u_int32_t, struct ssh *); 316int input_gssapi_errtok(int, u_int32_t, struct ssh *); 317#endif 318 319void userauth(Authctxt *, char *); 320 321static int sign_and_send_pubkey(struct ssh *ssh, Authctxt *, Identity *); 322static void pubkey_prepare(Authctxt *); 323static void pubkey_cleanup(Authctxt *); 324static void pubkey_reset(Authctxt *); 325static struct sshkey *load_identity_file(Identity *); 326 327static Authmethod *authmethod_get(char *authlist); 328static Authmethod *authmethod_lookup(const char *name); 329static char *authmethods_get(void); 330 331Authmethod authmethods[] = { 332#ifdef GSSAPI 333 {"gssapi-with-mic", 334 userauth_gssapi, 335 NULL, 336 &options.gss_authentication, 337 NULL}, 338#endif 339 {"hostbased", 340 userauth_hostbased, 341 NULL, 342 &options.hostbased_authentication, 343 NULL}, 344 {"publickey", 345 userauth_pubkey, 346 NULL, 347 &options.pubkey_authentication, 348 NULL}, 349 {"keyboard-interactive", 350 userauth_kbdint, 351 NULL, 352 &options.kbd_interactive_authentication, 353 &options.batch_mode}, 354 {"password", 355 userauth_passwd, 356 NULL, 357 &options.password_authentication, 358 &options.batch_mode}, 359 {"none", 360 userauth_none, 361 NULL, 362 NULL, 363 NULL}, 364 {NULL, NULL, NULL, NULL, NULL} 365}; 366 367void 368ssh_userauth2(const char *local_user, const char *server_user, char *host, 369 Sensitive *sensitive) 370{ 371 struct ssh *ssh = active_state; 372 Authctxt authctxt; 373 int r; 374 375 if (options.challenge_response_authentication) 376 options.kbd_interactive_authentication = 1; 377 if (options.preferred_authentications == NULL) 378 options.preferred_authentications = authmethods_get(); 379 380 /* setup authentication context */ 381 memset(&authctxt, 0, sizeof(authctxt)); 382 pubkey_prepare(&authctxt); 383 authctxt.server_user = server_user; 384 authctxt.local_user = local_user; 385 authctxt.host = host; 386 authctxt.service = "ssh-connection"; /* service name */ 387 authctxt.success = 0; 388 authctxt.method = authmethod_lookup("none"); 389 authctxt.authlist = NULL; 390 authctxt.methoddata = NULL; 391 authctxt.sensitive = sensitive; 392 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 393 authctxt.info_req_seen = 0; 394 authctxt.agent_fd = -1; 395 if (authctxt.method == NULL) 396 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 397 398 if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 || 399 (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 || 400 (r = sshpkt_send(ssh)) != 0) 401 fatal("%s: %s", __func__, ssh_err(r)); 402 403 ssh->authctxt = &authctxt; 404 ssh_dispatch_init(ssh, &input_userauth_error); 405 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info); 406 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept); 407 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */ 408 ssh->authctxt = NULL; 409 410 pubkey_cleanup(&authctxt); 411 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 412 413 if (!authctxt.success) 414 fatal("Authentication failed."); 415 debug("Authentication succeeded (%s).", authctxt.method->name); 416} 417 418/* ARGSUSED */ 419int 420input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh) 421{ 422 Authctxt *authctxt = ssh->authctxt; 423 int r; 424 425 if (ssh_packet_remaining(ssh) > 0) { 426 char *reply; 427 428 if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0) 429 goto out; 430 debug2("service_accept: %s", reply); 431 free(reply); 432 } else { 433 debug2("buggy server: service_accept w/o service"); 434 } 435 if ((r = sshpkt_get_end(ssh)) != 0) 436 goto out; 437 debug("SSH2_MSG_SERVICE_ACCEPT received"); 438 439 /* initial userauth request */ 440 userauth_none(authctxt); 441 442 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error); 443 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 444 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 445 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 446 r = 0; 447 out: 448 return r; 449} 450 451/* ARGSUSED */ 452int 453input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh) 454{ 455 return kex_input_ext_info(type, seqnr, ssh); 456} 457 458void 459userauth(Authctxt *authctxt, char *authlist) 460{ 461 struct ssh *ssh = active_state; /* XXX */ 462 463 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 464 authctxt->method->cleanup(authctxt); 465 466 free(authctxt->methoddata); 467 authctxt->methoddata = NULL; 468 if (authlist == NULL) { 469 authlist = authctxt->authlist; 470 } else { 471 free(authctxt->authlist); 472 authctxt->authlist = authlist; 473 } 474 for (;;) { 475 Authmethod *method = authmethod_get(authlist); 476 if (method == NULL) 477 fatal("%s@%s: Permission denied (%s).", 478 authctxt->server_user, authctxt->host, authlist); 479 authctxt->method = method; 480 481 /* reset the per method handler */ 482 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_PER_METHOD_MIN, 483 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 484 485 /* and try new method */ 486 if (method->userauth(authctxt) != 0) { 487 debug2("we sent a %s packet, wait for reply", method->name); 488 break; 489 } else { 490 debug2("we did not send a packet, disable method"); 491 method->enabled = NULL; 492 } 493 } 494} 495 496/* ARGSUSED */ 497int 498input_userauth_error(int type, u_int32_t seq, struct ssh *ssh) 499{ 500 fatal("input_userauth_error: bad message during authentication: " 501 "type %d", type); 502 return 0; 503} 504 505/* ARGSUSED */ 506int 507input_userauth_banner(int type, u_int32_t seq, struct ssh *ssh) 508{ 509 char *msg, *lang; 510 u_int len; 511 512 debug3("%s", __func__); 513 msg = packet_get_string(&len); 514 lang = packet_get_string(NULL); 515 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) 516 fmprintf(stderr, "%s", msg); 517 free(msg); 518 free(lang); 519 return 0; 520} 521 522/* ARGSUSED */ 523int 524input_userauth_success(int type, u_int32_t seq, struct ssh *ssh) 525{ 526 Authctxt *authctxt = ssh->authctxt; 527 528 if (authctxt == NULL) 529 fatal("input_userauth_success: no authentication context"); 530 free(authctxt->authlist); 531 authctxt->authlist = NULL; 532 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 533 authctxt->method->cleanup(authctxt); 534 free(authctxt->methoddata); 535 authctxt->methoddata = NULL; 536 authctxt->success = 1; /* break out */ 537 return 0; 538} 539 540int 541input_userauth_success_unexpected(int type, u_int32_t seq, struct ssh *ssh) 542{ 543 Authctxt *authctxt = ssh->authctxt; 544 545 if (authctxt == NULL) 546 fatal("%s: no authentication context", __func__); 547 548 fatal("Unexpected authentication success during %s.", 549 authctxt->method->name); 550 return 0; 551} 552 553/* ARGSUSED */ 554int 555input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh) 556{ 557 Authctxt *authctxt = ssh->authctxt; 558 char *authlist = NULL; 559 u_char partial; 560 int r; 561 562 if (authctxt == NULL) 563 fatal("input_userauth_failure: no authentication context"); 564 565 if ((r = sshpkt_get_cstring(ssh, &authlist, NULL)) != 0 || 566 (r = sshpkt_get_u8(ssh, &partial)) != 0 || 567 (r = sshpkt_get_end(ssh)) != 0) 568 goto out; 569 570 if (partial != 0) { 571 verbose("Authenticated with partial success."); 572 /* reset state */ 573 pubkey_reset(authctxt); 574 } 575 debug("Authentications that can continue: %s", authlist); 576 577 userauth(authctxt, authlist); 578 authlist = NULL; 579 out: 580 free(authlist); 581 return 0; 582} 583 584/* 585 * Format an identity for logging including filename, key type, fingerprint 586 * and location (agent, etc.). Caller must free. 587 */ 588static char * 589format_identity(Identity *id) 590{ 591 char *fp = NULL, *ret = NULL; 592 593 if (id->key != NULL) { 594 fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 595 SSH_FP_DEFAULT); 596 } 597 xasprintf(&ret, "%s %s%s%s%s%s%s", 598 id->filename, 599 id->key ? sshkey_type(id->key) : "", id->key ? " " : "", 600 fp ? fp : "", 601 id->userprovided ? " explicit" : "", 602 (id->key && (id->key->flags & SSHKEY_FLAG_EXT)) ? " token" : "", 603 id->agent_fd != -1 ? " agent" : ""); 604 free(fp); 605 return ret; 606} 607 608/* ARGSUSED */ 609int 610input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh) 611{ 612 Authctxt *authctxt = ssh->authctxt; 613 struct sshkey *key = NULL; 614 Identity *id = NULL; 615 int pktype, found = 0, sent = 0; 616 size_t blen; 617 char *pkalg = NULL, *fp = NULL, *ident = NULL; 618 u_char *pkblob = NULL; 619 int r; 620 621 if (authctxt == NULL) 622 fatal("input_userauth_pk_ok: no authentication context"); 623 624 if ((r = sshpkt_get_cstring(ssh, &pkalg, NULL)) != 0 || 625 (r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 || 626 (r = sshpkt_get_end(ssh)) != 0) 627 goto done; 628 629 if ((pktype = sshkey_type_from_name(pkalg)) == KEY_UNSPEC) { 630 debug("%s: server sent unknown pkalg %s", __func__, pkalg); 631 goto done; 632 } 633 if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) { 634 debug("no key from blob. pkalg %s: %s", pkalg, ssh_err(r)); 635 goto done; 636 } 637 if (key->type != pktype) { 638 error("input_userauth_pk_ok: type mismatch " 639 "for decoded key (received %d, expected %d)", 640 key->type, pktype); 641 goto done; 642 } 643 644 /* 645 * search keys in the reverse order, because last candidate has been 646 * moved to the end of the queue. this also avoids confusion by 647 * duplicate keys 648 */ 649 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 650 if (sshkey_equal(key, id->key)) { 651 found = 1; 652 break; 653 } 654 } 655 if (!found || id == NULL) { 656 fp = sshkey_fingerprint(key, options.fingerprint_hash, 657 SSH_FP_DEFAULT); 658 error("%s: server replied with unknown key: %s %s", __func__, 659 sshkey_type(key), fp == NULL ? "<ERROR>" : fp); 660 goto done; 661 } 662 ident = format_identity(id); 663 debug("Server accepts key: %s", ident); 664 sent = sign_and_send_pubkey(ssh, authctxt, id); 665 r = 0; 666 done: 667 sshkey_free(key); 668 free(ident); 669 free(fp); 670 free(pkalg); 671 free(pkblob); 672 673 /* try another method if we did not send a packet */ 674 if (r == 0 && sent == 0) 675 userauth(authctxt, NULL); 676 return r; 677} 678 679#ifdef GSSAPI 680int 681userauth_gssapi(Authctxt *authctxt) 682{ 683 struct ssh *ssh = active_state; /* XXX */ 684 Gssctxt *gssctxt = NULL; 685 static gss_OID_set gss_supported = NULL; 686 static u_int mech = 0; 687 OM_uint32 min; 688 int r, ok = 0; 689 690 /* Try one GSSAPI method at a time, rather than sending them all at 691 * once. */ 692 693 if (gss_supported == NULL) 694 gss_indicate_mechs(&min, &gss_supported); 695 696 /* Check to see if the mechanism is usable before we offer it */ 697 while (mech < gss_supported->count && !ok) { 698 /* My DER encoding requires length<128 */ 699 if (gss_supported->elements[mech].length < 128 && 700 ssh_gssapi_check_mechanism(&gssctxt, 701 &gss_supported->elements[mech], authctxt->host)) { 702 ok = 1; /* Mechanism works */ 703 } else { 704 mech++; 705 } 706 } 707 708 if (!ok) 709 return 0; 710 711 authctxt->methoddata=(void *)gssctxt; 712 713 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 714 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 715 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 716 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 717 (r = sshpkt_put_u32(ssh, 1)) != 0 || 718 (r = sshpkt_put_u32(ssh, 719 (gss_supported->elements[mech].length) + 2)) != 0 || 720 (r = sshpkt_put_u8(ssh, SSH_GSS_OIDTYPE)) != 0 || 721 (r = sshpkt_put_u8(ssh, 722 gss_supported->elements[mech].length)) != 0 || 723 (r = sshpkt_put(ssh, 724 gss_supported->elements[mech].elements, 725 gss_supported->elements[mech].length)) != 0 || 726 (r = sshpkt_send(ssh)) != 0) 727 fatal("%s: %s", __func__, ssh_err(r)); 728 729 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 730 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 731 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 732 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 733 734 mech++; /* Move along to next candidate */ 735 736 return 1; 737} 738 739static OM_uint32 740process_gssapi_token(struct ssh *ssh, gss_buffer_t recv_tok) 741{ 742 Authctxt *authctxt = ssh->authctxt; 743 Gssctxt *gssctxt = authctxt->methoddata; 744 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 745 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 746 gss_buffer_desc gssbuf; 747 OM_uint32 status, ms, flags; 748 int r; 749 750 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 751 recv_tok, &send_tok, &flags); 752 753 if (send_tok.length > 0) { 754 u_char type = GSS_ERROR(status) ? 755 SSH2_MSG_USERAUTH_GSSAPI_ERRTOK : 756 SSH2_MSG_USERAUTH_GSSAPI_TOKEN; 757 758 if ((r = sshpkt_start(ssh, type)) != 0 || 759 (r = sshpkt_put_string(ssh, send_tok.value, 760 send_tok.length)) != 0 || 761 (r = sshpkt_send(ssh)) != 0) 762 fatal("%s: %s", __func__, ssh_err(r)); 763 764 gss_release_buffer(&ms, &send_tok); 765 } 766 767 if (status == GSS_S_COMPLETE) { 768 /* send either complete or MIC, depending on mechanism */ 769 if (!(flags & GSS_C_INTEG_FLAG)) { 770 if ((r = sshpkt_start(ssh, 771 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE)) != 0 || 772 (r = sshpkt_send(ssh)) != 0) 773 fatal("%s: %s", __func__, ssh_err(r)); 774 } else { 775 struct sshbuf *b; 776 777 if ((b = sshbuf_new()) == NULL) 778 fatal("%s: sshbuf_new failed", __func__); 779 ssh_gssapi_buildmic(b, authctxt->server_user, 780 authctxt->service, "gssapi-with-mic"); 781 782 if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL) 783 fatal("%s: sshbuf_mutable_ptr failed", __func__); 784 gssbuf.length = sshbuf_len(b); 785 786 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 787 788 if (!GSS_ERROR(status)) { 789 if ((r = sshpkt_start(ssh, 790 SSH2_MSG_USERAUTH_GSSAPI_MIC)) != 0 || 791 (r = sshpkt_put_string(ssh, mic.value, 792 mic.length)) != 0 || 793 (r = sshpkt_send(ssh)) != 0) 794 fatal("%s: %s", __func__, ssh_err(r)); 795 } 796 797 sshbuf_free(b); 798 gss_release_buffer(&ms, &mic); 799 } 800 } 801 802 return status; 803} 804 805/* ARGSUSED */ 806int 807input_gssapi_response(int type, u_int32_t plen, struct ssh *ssh) 808{ 809 Authctxt *authctxt = ssh->authctxt; 810 Gssctxt *gssctxt; 811 size_t oidlen; 812 u_char *oidv = NULL; 813 int r; 814 815 if (authctxt == NULL) 816 fatal("input_gssapi_response: no authentication context"); 817 gssctxt = authctxt->methoddata; 818 819 /* Setup our OID */ 820 if ((r = sshpkt_get_string(ssh, &oidv, &oidlen)) != 0) 821 goto done; 822 823 if (oidlen <= 2 || 824 oidv[0] != SSH_GSS_OIDTYPE || 825 oidv[1] != oidlen - 2) { 826 debug("Badly encoded mechanism OID received"); 827 userauth(authctxt, NULL); 828 goto ok; 829 } 830 831 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 832 fatal("Server returned different OID than expected"); 833 834 if ((r = sshpkt_get_end(ssh)) != 0) 835 goto done; 836 837 if (GSS_ERROR(process_gssapi_token(ssh, GSS_C_NO_BUFFER))) { 838 /* Start again with next method on list */ 839 debug("Trying to start again"); 840 userauth(authctxt, NULL); 841 goto ok; 842 } 843 ok: 844 r = 0; 845 done: 846 free(oidv); 847 return r; 848} 849 850/* ARGSUSED */ 851int 852input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh) 853{ 854 Authctxt *authctxt = ssh->authctxt; 855 gss_buffer_desc recv_tok; 856 u_char *p = NULL; 857 size_t len; 858 OM_uint32 status; 859 int r; 860 861 if (authctxt == NULL) 862 fatal("input_gssapi_response: no authentication context"); 863 864 if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || 865 (r = sshpkt_get_end(ssh)) != 0) 866 goto out; 867 868 recv_tok.value = p; 869 recv_tok.length = len; 870 status = process_gssapi_token(ssh, &recv_tok); 871 872 /* Start again with the next method in the list */ 873 if (GSS_ERROR(status)) { 874 userauth(authctxt, NULL); 875 /* ok */ 876 } 877 r = 0; 878 out: 879 free(p); 880 return r; 881} 882 883/* ARGSUSED */ 884int 885input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh) 886{ 887 Authctxt *authctxt = ssh->authctxt; 888 Gssctxt *gssctxt; 889 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 890 gss_buffer_desc recv_tok; 891 OM_uint32 ms; 892 u_char *p = NULL; 893 size_t len; 894 int r; 895 896 if (authctxt == NULL) 897 fatal("input_gssapi_response: no authentication context"); 898 gssctxt = authctxt->methoddata; 899 900 if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || 901 (r = sshpkt_get_end(ssh)) != 0) { 902 free(p); 903 return r; 904 } 905 906 /* Stick it into GSSAPI and see what it says */ 907 recv_tok.value = p; 908 recv_tok.length = len; 909 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 910 &recv_tok, &send_tok, NULL); 911 free(p); 912 gss_release_buffer(&ms, &send_tok); 913 914 /* Server will be returning a failed packet after this one */ 915 return 0; 916} 917 918/* ARGSUSED */ 919int 920input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh) 921{ 922 char *msg = NULL; 923 char *lang = NULL; 924 int r; 925 926 if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* maj */ 927 (r = sshpkt_get_u32(ssh, NULL)) != 0 || /* min */ 928 (r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 929 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 930 goto out; 931 r = sshpkt_get_end(ssh); 932 debug("Server GSSAPI Error:\n%s", msg); 933 out: 934 free(msg); 935 free(lang); 936 return r; 937} 938#endif /* GSSAPI */ 939 940int 941userauth_none(Authctxt *authctxt) 942{ 943 struct ssh *ssh = active_state; /* XXX */ 944 int r; 945 946 /* initial userauth request */ 947 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 948 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 949 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 950 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 951 (r = sshpkt_send(ssh)) != 0) 952 fatal("%s: %s", __func__, ssh_err(r)); 953 return 1; 954} 955 956int 957userauth_passwd(Authctxt *authctxt) 958{ 959 struct ssh *ssh = active_state; /* XXX */ 960 static int attempt = 0; 961 char prompt[256]; 962 char *password; 963 const char *host = options.host_key_alias ? options.host_key_alias : 964 authctxt->host; 965 int r; 966 967 if (attempt++ >= options.number_of_password_prompts) 968 return 0; 969 970 if (attempt != 1) 971 error("Permission denied, please try again."); 972 973 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 974 authctxt->server_user, host); 975 password = read_passphrase(prompt, 0); 976 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 977 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 978 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 979 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 980 (r = sshpkt_put_u8(ssh, 0)) != 0 || 981 (r = sshpkt_put_cstring(ssh, password)) != 0 || 982 (r = sshpkt_add_padding(ssh, 64)) != 0 || 983 (r = sshpkt_send(ssh)) != 0) 984 fatal("%s: %s", __func__, ssh_err(r)); 985 986 if (password) 987 freezero(password, strlen(password)); 988 989 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 990 &input_userauth_passwd_changereq); 991 992 return 1; 993} 994 995/* 996 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 997 */ 998/* ARGSUSED */ 999int 1000input_userauth_passwd_changereq(int type, u_int32_t seqnr, struct ssh *ssh) 1001{ 1002 Authctxt *authctxt = ssh->authctxt; 1003 char *info = NULL, *lang = NULL, *password = NULL, *retype = NULL; 1004 char prompt[256]; 1005 const char *host; 1006 int r; 1007 1008 debug2("input_userauth_passwd_changereq"); 1009 1010 if (authctxt == NULL) 1011 fatal("input_userauth_passwd_changereq: " 1012 "no authentication context"); 1013 host = options.host_key_alias ? options.host_key_alias : authctxt->host; 1014 1015 if ((r = sshpkt_get_cstring(ssh, &info, NULL)) != 0 || 1016 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 1017 goto out; 1018 if (strlen(info) > 0) 1019 logit("%s", info); 1020 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1021 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1022 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1023 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1024 (r = sshpkt_put_u8(ssh, 1)) != 0) /* additional info */ 1025 goto out; 1026 1027 snprintf(prompt, sizeof(prompt), 1028 "Enter %.30s@%.128s's old password: ", 1029 authctxt->server_user, host); 1030 password = read_passphrase(prompt, 0); 1031 if ((r = sshpkt_put_cstring(ssh, password)) != 0) 1032 goto out; 1033 1034 freezero(password, strlen(password)); 1035 password = NULL; 1036 while (password == NULL) { 1037 snprintf(prompt, sizeof(prompt), 1038 "Enter %.30s@%.128s's new password: ", 1039 authctxt->server_user, host); 1040 password = read_passphrase(prompt, RP_ALLOW_EOF); 1041 if (password == NULL) { 1042 /* bail out */ 1043 r = 0; 1044 goto out; 1045 } 1046 snprintf(prompt, sizeof(prompt), 1047 "Retype %.30s@%.128s's new password: ", 1048 authctxt->server_user, host); 1049 retype = read_passphrase(prompt, 0); 1050 if (strcmp(password, retype) != 0) { 1051 freezero(password, strlen(password)); 1052 logit("Mismatch; try again, EOF to quit."); 1053 password = NULL; 1054 } 1055 freezero(retype, strlen(retype)); 1056 } 1057 if ((r = sshpkt_put_cstring(ssh, password)) != 0 || 1058 (r = sshpkt_add_padding(ssh, 64)) != 0 || 1059 (r = sshpkt_send(ssh)) != 0) 1060 goto out; 1061 1062 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1063 &input_userauth_passwd_changereq); 1064 r = 0; 1065 out: 1066 if (password) 1067 freezero(password, strlen(password)); 1068 free(info); 1069 free(lang); 1070 return r; 1071} 1072 1073/* 1074 * Select an algorithm for publickey signatures. 1075 * Returns algorithm (caller must free) or NULL if no mutual algorithm found. 1076 * 1077 * Call with ssh==NULL to ignore server-sig-algs extension list and 1078 * only attempt with the key's base signature type. 1079 */ 1080static char * 1081key_sig_algorithm(struct ssh *ssh, const struct sshkey *key) 1082{ 1083 char *allowed, *oallowed, *cp, *tmp, *alg = NULL; 1084 1085 /* 1086 * The signature algorithm will only differ from the key algorithm 1087 * for RSA keys/certs and when the server advertises support for 1088 * newer (SHA2) algorithms. 1089 */ 1090 if (ssh == NULL || ssh->kex->server_sig_algs == NULL || 1091 (key->type != KEY_RSA && key->type != KEY_RSA_CERT) || 1092 (key->type == KEY_RSA_CERT && (datafellows & SSH_BUG_SIGTYPE))) { 1093 /* Filter base key signature alg against our configuration */ 1094 return match_list(sshkey_ssh_name(key), 1095 options.pubkey_key_types, NULL); 1096 } 1097 1098 /* 1099 * For RSA keys/certs, since these might have a different sig type: 1100 * find the first entry in PubkeyAcceptedKeyTypes of the right type 1101 * that also appears in the supported signature algorithms list from 1102 * the server. 1103 */ 1104 oallowed = allowed = xstrdup(options.pubkey_key_types); 1105 while ((cp = strsep(&allowed, ",")) != NULL) { 1106 if (sshkey_type_from_name(cp) != key->type) 1107 continue; 1108 tmp = match_list(sshkey_sigalg_by_name(cp), ssh->kex->server_sig_algs, NULL); 1109 if (tmp != NULL) 1110 alg = xstrdup(cp); 1111 free(tmp); 1112 if (alg != NULL) 1113 break; 1114 } 1115 free(oallowed); 1116 return alg; 1117} 1118 1119static int 1120identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 1121 const u_char *data, size_t datalen, u_int compat, const char *alg) 1122{ 1123 struct sshkey *prv; 1124 int r; 1125 1126 /* The agent supports this key. */ 1127 if (id->key != NULL && id->agent_fd != -1) { 1128 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 1129 data, datalen, alg, compat); 1130 } 1131 1132 /* 1133 * We have already loaded the private key or the private key is 1134 * stored in external hardware. 1135 */ 1136 if (id->key != NULL && 1137 (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))) { 1138 if ((r = sshkey_sign(id->key, sigp, lenp, data, datalen, 1139 alg, compat)) != 0) 1140 return r; 1141 /* 1142 * PKCS#11 tokens may not support all signature algorithms, 1143 * so check what we get back. 1144 */ 1145 if ((r = sshkey_check_sigtype(*sigp, *lenp, alg)) != 0) 1146 return r; 1147 return 0; 1148 } 1149 1150 /* Load the private key from the file. */ 1151 if ((prv = load_identity_file(id)) == NULL) 1152 return SSH_ERR_KEY_NOT_FOUND; 1153 if (id->key != NULL && !sshkey_equal_public(prv, id->key)) { 1154 error("%s: private key %s contents do not match public", 1155 __func__, id->filename); 1156 return SSH_ERR_KEY_NOT_FOUND; 1157 } 1158 r = sshkey_sign(prv, sigp, lenp, data, datalen, alg, compat); 1159 sshkey_free(prv); 1160 return r; 1161} 1162 1163static int 1164id_filename_matches(Identity *id, Identity *private_id) 1165{ 1166 const char *suffixes[] = { ".pub", "-cert.pub", NULL }; 1167 size_t len = strlen(id->filename), plen = strlen(private_id->filename); 1168 size_t i, slen; 1169 1170 if (strcmp(id->filename, private_id->filename) == 0) 1171 return 1; 1172 for (i = 0; suffixes[i]; i++) { 1173 slen = strlen(suffixes[i]); 1174 if (len > slen && plen == len - slen && 1175 strcmp(id->filename + (len - slen), suffixes[i]) == 0 && 1176 memcmp(id->filename, private_id->filename, plen) == 0) 1177 return 1; 1178 } 1179 return 0; 1180} 1181 1182static int 1183sign_and_send_pubkey(struct ssh *ssh, Authctxt *authctxt, Identity *id) 1184{ 1185 struct sshbuf *b = NULL; 1186 Identity *private_id, *sign_id = NULL; 1187 u_char *signature = NULL; 1188 size_t slen = 0, skip = 0; 1189 int r, fallback_sigtype, sent = 0; 1190 char *alg = NULL, *fp = NULL; 1191 const char *loc = ""; 1192 1193 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1194 SSH_FP_DEFAULT)) == NULL) 1195 return 0; 1196 1197 debug3("%s: %s %s", __func__, sshkey_type(id->key), fp); 1198 1199 /* 1200 * If the key is an certificate, try to find a matching private key 1201 * and use it to complete the signature. 1202 * If no such private key exists, fall back to trying the certificate 1203 * key itself in case it has a private half already loaded. 1204 * This will try to set sign_id to the private key that will perform 1205 * the signature. 1206 */ 1207 if (sshkey_is_cert(id->key)) { 1208 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1209 if (sshkey_equal_public(id->key, private_id->key) && 1210 id->key->type != private_id->key->type) { 1211 sign_id = private_id; 1212 break; 1213 } 1214 } 1215 /* 1216 * Exact key matches are preferred, but also allow 1217 * filename matches for non-PKCS#11/agent keys that 1218 * didn't load public keys. This supports the case 1219 * of keeping just a private key file and public 1220 * certificate on disk. 1221 */ 1222 if (sign_id == NULL && 1223 !id->isprivate && id->agent_fd == -1 && 1224 (id->key->flags & SSHKEY_FLAG_EXT) == 0) { 1225 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1226 if (private_id->key == NULL && 1227 id_filename_matches(id, private_id)) { 1228 sign_id = private_id; 1229 break; 1230 } 1231 } 1232 } 1233 if (sign_id != NULL) { 1234 debug2("%s: using private key \"%s\"%s for " 1235 "certificate", __func__, id->filename, 1236 id->agent_fd != -1 ? " from agent" : ""); 1237 } else { 1238 debug("%s: no separate private key for certificate " 1239 "\"%s\"", __func__, id->filename); 1240 } 1241 } 1242 1243 /* 1244 * If the above didn't select another identity to do the signing 1245 * then default to the one we started with. 1246 */ 1247 if (sign_id == NULL) 1248 sign_id = id; 1249 1250 /* assemble and sign data */ 1251 for (fallback_sigtype = 0; fallback_sigtype <= 1; fallback_sigtype++) { 1252 free(alg); 1253 slen = 0; 1254 signature = NULL; 1255 if ((alg = key_sig_algorithm(fallback_sigtype ? NULL : ssh, 1256 id->key)) == NULL) { 1257 error("%s: no mutual signature supported", __func__); 1258 goto out; 1259 } 1260 debug3("%s: signing using %s", __func__, alg); 1261 1262 sshbuf_free(b); 1263 if ((b = sshbuf_new()) == NULL) 1264 fatal("%s: sshbuf_new failed", __func__); 1265 if (datafellows & SSH_OLD_SESSIONID) { 1266 if ((r = sshbuf_put(b, session_id2, 1267 session_id2_len)) != 0) { 1268 fatal("%s: sshbuf_put: %s", 1269 __func__, ssh_err(r)); 1270 } 1271 } else { 1272 if ((r = sshbuf_put_string(b, session_id2, 1273 session_id2_len)) != 0) { 1274 fatal("%s: sshbuf_put_string: %s", 1275 __func__, ssh_err(r)); 1276 } 1277 } 1278 skip = sshbuf_len(b); 1279 if ((r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1280 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1281 (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || 1282 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1283 (r = sshbuf_put_u8(b, 1)) != 0 || 1284 (r = sshbuf_put_cstring(b, alg)) != 0 || 1285 (r = sshkey_puts(id->key, b)) != 0) { 1286 fatal("%s: assemble signed data: %s", 1287 __func__, ssh_err(r)); 1288 } 1289 1290 /* generate signature */ 1291 r = identity_sign(sign_id, &signature, &slen, 1292 sshbuf_ptr(b), sshbuf_len(b), datafellows, alg); 1293 if (r == 0) 1294 break; 1295 else if (r == SSH_ERR_KEY_NOT_FOUND) 1296 goto out; /* soft failure */ 1297 else if (r == SSH_ERR_SIGN_ALG_UNSUPPORTED && 1298 !fallback_sigtype) { 1299 if (sign_id->agent_fd != -1) 1300 loc = "agent "; 1301 else if ((sign_id->key->flags & SSHKEY_FLAG_EXT) != 0) 1302 loc = "token "; 1303 logit("%skey %s %s returned incorrect signature type", 1304 loc, sshkey_type(id->key), fp); 1305 continue; 1306 } 1307 error("%s: signing failed: %s", __func__, ssh_err(r)); 1308 goto out; 1309 } 1310 if (slen == 0 || signature == NULL) /* shouldn't happen */ 1311 fatal("%s: no signature", __func__); 1312 1313 /* append signature */ 1314 if ((r = sshbuf_put_string(b, signature, slen)) != 0) 1315 fatal("%s: append signature: %s", __func__, ssh_err(r)); 1316 1317#ifdef DEBUG_PK 1318 sshbuf_dump(b, stderr); 1319#endif 1320 /* skip session id and packet type */ 1321 if ((r = sshbuf_consume(b, skip + 1)) != 0) 1322 fatal("%s: consume: %s", __func__, ssh_err(r)); 1323 1324 /* put remaining data from buffer into packet */ 1325 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1326 (r = sshpkt_putb(ssh, b)) != 0 || 1327 (r = sshpkt_send(ssh)) != 0) 1328 fatal("%s: enqueue request: %s", __func__, ssh_err(r)); 1329 1330 /* success */ 1331 sent = 1; 1332 1333 out: 1334 free(fp); 1335 free(alg); 1336 sshbuf_free(b); 1337 freezero(signature, slen); 1338 return sent; 1339} 1340 1341static int 1342send_pubkey_test(struct ssh *ssh, Authctxt *authctxt, Identity *id) 1343{ 1344 u_char *blob = NULL; 1345 char *alg = NULL; 1346 size_t bloblen; 1347 u_int have_sig = 0; 1348 int sent = 0, r; 1349 1350 if ((alg = key_sig_algorithm(ssh, id->key)) == NULL) { 1351 debug("%s: no mutual signature algorithm", __func__); 1352 goto out; 1353 } 1354 1355 if ((r = sshkey_to_blob(id->key, &blob, &bloblen)) != 0) { 1356 /* we cannot handle this key */ 1357 debug3("%s: cannot handle key", __func__); 1358 goto out; 1359 } 1360 /* register callback for USERAUTH_PK_OK message */ 1361 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1362 1363 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1364 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1365 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1366 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1367 (r = sshpkt_put_u8(ssh, have_sig)) != 0 || 1368 (r = sshpkt_put_cstring(ssh, alg)) != 0 || 1369 (r = sshpkt_put_string(ssh, blob, bloblen)) != 0 || 1370 (r = sshpkt_send(ssh)) != 0) 1371 fatal("%s: %s", __func__, ssh_err(r)); 1372 sent = 1; 1373 1374 out: 1375 free(alg); 1376 free(blob); 1377 return sent; 1378} 1379 1380static struct sshkey * 1381load_identity_file(Identity *id) 1382{ 1383 struct sshkey *private = NULL; 1384 char prompt[300], *passphrase, *comment; 1385 int r, perm_ok = 0, quit = 0, i; 1386 struct stat st; 1387 1388 if (stat(id->filename, &st) < 0) { 1389 (id->userprovided ? logit : debug3)("no such identity: %s: %s", 1390 id->filename, strerror(errno)); 1391 return NULL; 1392 } 1393 snprintf(prompt, sizeof prompt, 1394 "Enter passphrase for key '%.100s': ", id->filename); 1395 for (i = 0; i <= options.number_of_password_prompts; i++) { 1396 if (i == 0) 1397 passphrase = ""; 1398 else { 1399 passphrase = read_passphrase(prompt, 0); 1400 if (*passphrase == '\0') { 1401 debug2("no passphrase given, try next key"); 1402 free(passphrase); 1403 break; 1404 } 1405 } 1406 switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename, 1407 passphrase, &private, &comment, &perm_ok))) { 1408 case 0: 1409 break; 1410 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1411 if (options.batch_mode) { 1412 quit = 1; 1413 break; 1414 } 1415 if (i != 0) 1416 debug2("bad passphrase given, try again..."); 1417 break; 1418 case SSH_ERR_SYSTEM_ERROR: 1419 if (errno == ENOENT) { 1420 debug2("Load key \"%s\": %s", 1421 id->filename, ssh_err(r)); 1422 quit = 1; 1423 break; 1424 } 1425 /* FALLTHROUGH */ 1426 default: 1427 error("Load key \"%s\": %s", id->filename, ssh_err(r)); 1428 quit = 1; 1429 break; 1430 } 1431 if (!quit && private != NULL && id->agent_fd == -1 && 1432 !(id->key && id->isprivate)) 1433 maybe_add_key_to_agent(id->filename, private, comment, 1434 passphrase); 1435 if (i > 0) 1436 freezero(passphrase, strlen(passphrase)); 1437 free(comment); 1438 if (private != NULL || quit) 1439 break; 1440 } 1441 return private; 1442} 1443 1444static int 1445key_type_allowed_by_config(struct sshkey *key) 1446{ 1447 if (match_pattern_list(sshkey_ssh_name(key), 1448 options.pubkey_key_types, 0) == 1) 1449 return 1; 1450 1451 /* RSA keys/certs might be allowed by alternate signature types */ 1452 switch (key->type) { 1453 case KEY_RSA: 1454 if (match_pattern_list("rsa-sha2-512", 1455 options.pubkey_key_types, 0) == 1) 1456 return 1; 1457 if (match_pattern_list("rsa-sha2-256", 1458 options.pubkey_key_types, 0) == 1) 1459 return 1; 1460 break; 1461 case KEY_RSA_CERT: 1462 if (match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", 1463 options.pubkey_key_types, 0) == 1) 1464 return 1; 1465 if (match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", 1466 options.pubkey_key_types, 0) == 1) 1467 return 1; 1468 break; 1469 } 1470 return 0; 1471} 1472 1473 1474/* 1475 * try keys in the following order: 1476 * 1. certificates listed in the config file 1477 * 2. other input certificates 1478 * 3. agent keys that are found in the config file 1479 * 4. other agent keys 1480 * 5. keys that are only listed in the config file 1481 */ 1482static void 1483pubkey_prepare(Authctxt *authctxt) 1484{ 1485 struct identity *id, *id2, *tmp; 1486 struct idlist agent, files, *preferred; 1487 struct sshkey *key; 1488 int agent_fd = -1, i, r, found; 1489 size_t j; 1490 struct ssh_identitylist *idlist; 1491 char *ident; 1492 1493 TAILQ_INIT(&agent); /* keys from the agent */ 1494 TAILQ_INIT(&files); /* keys from the config file */ 1495 preferred = &authctxt->keys; 1496 TAILQ_INIT(preferred); /* preferred order of keys */ 1497 1498 /* list of keys stored in the filesystem and PKCS#11 */ 1499 for (i = 0; i < options.num_identity_files; i++) { 1500 key = options.identity_keys[i]; 1501 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1502 continue; 1503 options.identity_keys[i] = NULL; 1504 id = xcalloc(1, sizeof(*id)); 1505 id->agent_fd = -1; 1506 id->key = key; 1507 id->filename = xstrdup(options.identity_files[i]); 1508 id->userprovided = options.identity_file_userprovided[i]; 1509 TAILQ_INSERT_TAIL(&files, id, next); 1510 } 1511 /* list of certificates specified by user */ 1512 for (i = 0; i < options.num_certificate_files; i++) { 1513 key = options.certificates[i]; 1514 if (!sshkey_is_cert(key) || key->cert == NULL || 1515 key->cert->type != SSH2_CERT_TYPE_USER) 1516 continue; 1517 id = xcalloc(1, sizeof(*id)); 1518 id->agent_fd = -1; 1519 id->key = key; 1520 id->filename = xstrdup(options.certificate_files[i]); 1521 id->userprovided = options.certificate_file_userprovided[i]; 1522 TAILQ_INSERT_TAIL(preferred, id, next); 1523 } 1524 /* list of keys supported by the agent */ 1525 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1526 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1527 debug("%s: ssh_get_authentication_socket: %s", 1528 __func__, ssh_err(r)); 1529 } else if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 1530 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1531 debug("%s: ssh_fetch_identitylist: %s", 1532 __func__, ssh_err(r)); 1533 close(agent_fd); 1534 } else { 1535 for (j = 0; j < idlist->nkeys; j++) { 1536 found = 0; 1537 TAILQ_FOREACH(id, &files, next) { 1538 /* 1539 * agent keys from the config file are 1540 * preferred 1541 */ 1542 if (sshkey_equal(idlist->keys[j], id->key)) { 1543 TAILQ_REMOVE(&files, id, next); 1544 TAILQ_INSERT_TAIL(preferred, id, next); 1545 id->agent_fd = agent_fd; 1546 found = 1; 1547 break; 1548 } 1549 } 1550 if (!found && !options.identities_only) { 1551 id = xcalloc(1, sizeof(*id)); 1552 /* XXX "steals" key/comment from idlist */ 1553 id->key = idlist->keys[j]; 1554 id->filename = idlist->comments[j]; 1555 idlist->keys[j] = NULL; 1556 idlist->comments[j] = NULL; 1557 id->agent_fd = agent_fd; 1558 TAILQ_INSERT_TAIL(&agent, id, next); 1559 } 1560 } 1561 ssh_free_identitylist(idlist); 1562 /* append remaining agent keys */ 1563 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1564 TAILQ_REMOVE(&agent, id, next); 1565 TAILQ_INSERT_TAIL(preferred, id, next); 1566 } 1567 authctxt->agent_fd = agent_fd; 1568 } 1569 /* Prefer PKCS11 keys that are explicitly listed */ 1570 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1571 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1572 continue; 1573 found = 0; 1574 TAILQ_FOREACH(id2, &files, next) { 1575 if (id2->key == NULL || 1576 (id2->key->flags & SSHKEY_FLAG_EXT) == 0) 1577 continue; 1578 if (sshkey_equal(id->key, id2->key)) { 1579 TAILQ_REMOVE(&files, id, next); 1580 TAILQ_INSERT_TAIL(preferred, id, next); 1581 found = 1; 1582 break; 1583 } 1584 } 1585 /* If IdentitiesOnly set and key not found then don't use it */ 1586 if (!found && options.identities_only) { 1587 TAILQ_REMOVE(&files, id, next); 1588 freezero(id, sizeof(*id)); 1589 } 1590 } 1591 /* append remaining keys from the config file */ 1592 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1593 TAILQ_REMOVE(&files, id, next); 1594 TAILQ_INSERT_TAIL(preferred, id, next); 1595 } 1596 /* finally, filter by PubkeyAcceptedKeyTypes */ 1597 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1598 if (id->key != NULL && !key_type_allowed_by_config(id->key)) { 1599 debug("Skipping %s key %s - " 1600 "not in PubkeyAcceptedKeyTypes", 1601 sshkey_ssh_name(id->key), id->filename); 1602 TAILQ_REMOVE(preferred, id, next); 1603 sshkey_free(id->key); 1604 free(id->filename); 1605 memset(id, 0, sizeof(*id)); 1606 continue; 1607 } 1608 } 1609 /* List the keys we plan on using */ 1610 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1611 ident = format_identity(id); 1612 debug("Will attempt key: %s", ident); 1613 free(ident); 1614 } 1615 debug2("%s: done", __func__); 1616} 1617 1618static void 1619pubkey_cleanup(Authctxt *authctxt) 1620{ 1621 Identity *id; 1622 1623 if (authctxt->agent_fd != -1) 1624 ssh_close_authentication_socket(authctxt->agent_fd); 1625 for (id = TAILQ_FIRST(&authctxt->keys); id; 1626 id = TAILQ_FIRST(&authctxt->keys)) { 1627 TAILQ_REMOVE(&authctxt->keys, id, next); 1628 sshkey_free(id->key); 1629 free(id->filename); 1630 free(id); 1631 } 1632} 1633 1634static void 1635pubkey_reset(Authctxt *authctxt) 1636{ 1637 Identity *id; 1638 1639 TAILQ_FOREACH(id, &authctxt->keys, next) 1640 id->tried = 0; 1641} 1642 1643static int 1644try_identity(Identity *id) 1645{ 1646 if (!id->key) 1647 return (0); 1648 if (sshkey_type_plain(id->key->type) == KEY_RSA && 1649 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1650 debug("Skipped %s key %s for RSA/MD5 server", 1651 sshkey_type(id->key), id->filename); 1652 return (0); 1653 } 1654 return 1; 1655} 1656 1657int 1658userauth_pubkey(Authctxt *authctxt) 1659{ 1660 struct ssh *ssh = active_state; /* XXX */ 1661 Identity *id; 1662 int sent = 0; 1663 char *ident; 1664 1665 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1666 if (id->tried++) 1667 return (0); 1668 /* move key to the end of the queue */ 1669 TAILQ_REMOVE(&authctxt->keys, id, next); 1670 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1671 /* 1672 * send a test message if we have the public key. for 1673 * encrypted keys we cannot do this and have to load the 1674 * private key instead 1675 */ 1676 if (id->key != NULL) { 1677 if (try_identity(id)) { 1678 ident = format_identity(id); 1679 debug("Offering public key: %s", ident); 1680 free(ident); 1681 sent = send_pubkey_test(ssh, authctxt, id); 1682 } 1683 } else { 1684 debug("Trying private key: %s", id->filename); 1685 id->key = load_identity_file(id); 1686 if (id->key != NULL) { 1687 if (try_identity(id)) { 1688 id->isprivate = 1; 1689 sent = sign_and_send_pubkey(ssh, 1690 authctxt, id); 1691 } 1692 sshkey_free(id->key); 1693 id->key = NULL; 1694 id->isprivate = 0; 1695 } 1696 } 1697 if (sent) 1698 return (sent); 1699 } 1700 return (0); 1701} 1702 1703/* 1704 * Send userauth request message specifying keyboard-interactive method. 1705 */ 1706int 1707userauth_kbdint(Authctxt *authctxt) 1708{ 1709 struct ssh *ssh = active_state; /* XXX */ 1710 static int attempt = 0; 1711 int r; 1712 1713 if (attempt++ >= options.number_of_password_prompts) 1714 return 0; 1715 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1716 if (attempt > 1 && !authctxt->info_req_seen) { 1717 debug3("userauth_kbdint: disable: no info_req_seen"); 1718 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1719 return 0; 1720 } 1721 1722 debug2("userauth_kbdint"); 1723 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1724 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1725 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1726 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1727 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* lang */ 1728 (r = sshpkt_put_cstring(ssh, options.kbd_interactive_devices ? 1729 options.kbd_interactive_devices : "")) != 0 || 1730 (r = sshpkt_send(ssh)) != 0) 1731 fatal("%s: %s", __func__, ssh_err(r)); 1732 1733 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1734 return 1; 1735} 1736 1737/* 1738 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1739 */ 1740int 1741input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh) 1742{ 1743 Authctxt *authctxt = ssh->authctxt; 1744 char *name = NULL, *inst = NULL, *lang = NULL, *prompt = NULL; 1745 char *response = NULL; 1746 u_char echo = 0; 1747 u_int num_prompts, i; 1748 int r; 1749 1750 debug2("input_userauth_info_req"); 1751 1752 if (authctxt == NULL) 1753 fatal("input_userauth_info_req: no authentication context"); 1754 1755 authctxt->info_req_seen = 1; 1756 1757 if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 || 1758 (r = sshpkt_get_cstring(ssh, &inst, NULL)) != 0 || 1759 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 1760 goto out; 1761 if (strlen(name) > 0) 1762 logit("%s", name); 1763 if (strlen(inst) > 0) 1764 logit("%s", inst); 1765 1766 if ((r = sshpkt_get_u32(ssh, &num_prompts)) != 0) 1767 goto out; 1768 /* 1769 * Begin to build info response packet based on prompts requested. 1770 * We commit to providing the correct number of responses, so if 1771 * further on we run into a problem that prevents this, we have to 1772 * be sure and clean this up and send a correct error response. 1773 */ 1774 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE)) != 0 || 1775 (r = sshpkt_put_u32(ssh, num_prompts)) != 0) 1776 goto out; 1777 1778 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1779 for (i = 0; i < num_prompts; i++) { 1780 if ((r = sshpkt_get_cstring(ssh, &prompt, NULL)) != 0 || 1781 (r = sshpkt_get_u8(ssh, &echo)) != 0) 1782 goto out; 1783 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1784 if ((r = sshpkt_put_cstring(ssh, response)) != 0) 1785 goto out; 1786 freezero(response, strlen(response)); 1787 free(prompt); 1788 response = prompt = NULL; 1789 } 1790 /* done with parsing incoming message. */ 1791 if ((r = sshpkt_get_end(ssh)) != 0 || 1792 (r = sshpkt_add_padding(ssh, 64)) != 0) 1793 goto out; 1794 r = sshpkt_send(ssh); 1795 out: 1796 if (response) 1797 freezero(response, strlen(response)); 1798 free(prompt); 1799 free(name); 1800 free(inst); 1801 free(lang); 1802 return r; 1803} 1804 1805static int 1806ssh_keysign(struct sshkey *key, u_char **sigp, size_t *lenp, 1807 const u_char *data, size_t datalen) 1808{ 1809 struct sshbuf *b; 1810 struct stat st; 1811 pid_t pid; 1812 int i, r, to[2], from[2], status, sock = packet_get_connection_in(); 1813 u_char rversion = 0, version = 2; 1814 void (*osigchld)(int); 1815 1816 *sigp = NULL; 1817 *lenp = 0; 1818 1819 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1820 error("%s: not installed: %s", __func__, strerror(errno)); 1821 return -1; 1822 } 1823 if (fflush(stdout) != 0) { 1824 error("%s: fflush: %s", __func__, strerror(errno)); 1825 return -1; 1826 } 1827 if (pipe(to) < 0) { 1828 error("%s: pipe: %s", __func__, strerror(errno)); 1829 return -1; 1830 } 1831 if (pipe(from) < 0) { 1832 error("%s: pipe: %s", __func__, strerror(errno)); 1833 return -1; 1834 } 1835 if ((pid = fork()) < 0) { 1836 error("%s: fork: %s", __func__, strerror(errno)); 1837 return -1; 1838 } 1839 osigchld = signal(SIGCHLD, SIG_DFL); 1840 if (pid == 0) { 1841 /* keep the socket on exec */ 1842 fcntl(sock, F_SETFD, 0); 1843 close(from[0]); 1844 if (dup2(from[1], STDOUT_FILENO) < 0) 1845 fatal("%s: dup2: %s", __func__, strerror(errno)); 1846 close(to[1]); 1847 if (dup2(to[0], STDIN_FILENO) < 0) 1848 fatal("%s: dup2: %s", __func__, strerror(errno)); 1849 close(from[1]); 1850 close(to[0]); 1851 /* Close everything but stdio and the socket */ 1852 for (i = STDERR_FILENO + 1; i < sock; i++) 1853 close(i); 1854 closefrom(sock + 1); 1855 debug3("%s: [child] pid=%ld, exec %s", 1856 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1857 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL); 1858 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1859 strerror(errno)); 1860 } 1861 close(from[1]); 1862 close(to[0]); 1863 1864 if ((b = sshbuf_new()) == NULL) 1865 fatal("%s: sshbuf_new failed", __func__); 1866 /* send # of sock, data to be signed */ 1867 if ((r = sshbuf_put_u32(b, sock)) != 0 || 1868 (r = sshbuf_put_string(b, data, datalen)) != 0) 1869 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1870 if (ssh_msg_send(to[1], version, b) == -1) 1871 fatal("%s: couldn't send request", __func__); 1872 sshbuf_reset(b); 1873 r = ssh_msg_recv(from[0], b); 1874 close(from[0]); 1875 close(to[1]); 1876 if (r < 0) { 1877 error("%s: no reply", __func__); 1878 goto fail; 1879 } 1880 1881 errno = 0; 1882 while (waitpid(pid, &status, 0) < 0) { 1883 if (errno != EINTR) { 1884 error("%s: waitpid %ld: %s", 1885 __func__, (long)pid, strerror(errno)); 1886 goto fail; 1887 } 1888 } 1889 if (!WIFEXITED(status)) { 1890 error("%s: exited abnormally", __func__); 1891 goto fail; 1892 } 1893 if (WEXITSTATUS(status) != 0) { 1894 error("%s: exited with status %d", 1895 __func__, WEXITSTATUS(status)); 1896 goto fail; 1897 } 1898 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 1899 error("%s: buffer error: %s", __func__, ssh_err(r)); 1900 goto fail; 1901 } 1902 if (rversion != version) { 1903 error("%s: bad version", __func__); 1904 goto fail; 1905 } 1906 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 1907 error("%s: buffer error: %s", __func__, ssh_err(r)); 1908 fail: 1909 signal(SIGCHLD, osigchld); 1910 sshbuf_free(b); 1911 return -1; 1912 } 1913 signal(SIGCHLD, osigchld); 1914 sshbuf_free(b); 1915 1916 return 0; 1917} 1918 1919int 1920userauth_hostbased(Authctxt *authctxt) 1921{ 1922 struct ssh *ssh = active_state; /* XXX */ 1923 struct sshkey *private = NULL; 1924 struct sshbuf *b = NULL; 1925 u_char *sig = NULL, *keyblob = NULL; 1926 char *fp = NULL, *chost = NULL, *lname = NULL; 1927 size_t siglen = 0, keylen = 0; 1928 int i, r, success = 0; 1929 1930 if (authctxt->ktypes == NULL) { 1931 authctxt->oktypes = xstrdup(options.hostbased_key_types); 1932 authctxt->ktypes = authctxt->oktypes; 1933 } 1934 1935 /* 1936 * Work through each listed type pattern in HostbasedKeyTypes, 1937 * trying each hostkey that matches the type in turn. 1938 */ 1939 for (;;) { 1940 if (authctxt->active_ktype == NULL) 1941 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 1942 if (authctxt->active_ktype == NULL || 1943 *authctxt->active_ktype == '\0') 1944 break; 1945 debug3("%s: trying key type %s", __func__, 1946 authctxt->active_ktype); 1947 1948 /* check for a useful key */ 1949 private = NULL; 1950 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 1951 if (authctxt->sensitive->keys[i] == NULL || 1952 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 1953 continue; 1954 if (match_pattern_list( 1955 sshkey_ssh_name(authctxt->sensitive->keys[i]), 1956 authctxt->active_ktype, 0) != 1) 1957 continue; 1958 /* we take and free the key */ 1959 private = authctxt->sensitive->keys[i]; 1960 authctxt->sensitive->keys[i] = NULL; 1961 break; 1962 } 1963 /* Found one */ 1964 if (private != NULL) 1965 break; 1966 /* No more keys of this type; advance */ 1967 authctxt->active_ktype = NULL; 1968 } 1969 if (private == NULL) { 1970 free(authctxt->oktypes); 1971 authctxt->oktypes = authctxt->ktypes = NULL; 1972 authctxt->active_ktype = NULL; 1973 debug("No more client hostkeys for hostbased authentication."); 1974 goto out; 1975 } 1976 1977 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 1978 SSH_FP_DEFAULT)) == NULL) { 1979 error("%s: sshkey_fingerprint failed", __func__); 1980 goto out; 1981 } 1982 debug("%s: trying hostkey %s %s", 1983 __func__, sshkey_ssh_name(private), fp); 1984 1985 /* figure out a name for the client host */ 1986 if ((lname = get_local_name(packet_get_connection_in())) == NULL) { 1987 error("%s: cannot get local ipaddr/name", __func__); 1988 goto out; 1989 } 1990 1991 /* XXX sshbuf_put_stringf? */ 1992 xasprintf(&chost, "%s.", lname); 1993 debug2("%s: chost %s", __func__, chost); 1994 1995 /* construct data */ 1996 if ((b = sshbuf_new()) == NULL) { 1997 error("%s: sshbuf_new failed", __func__); 1998 goto out; 1999 } 2000 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 2001 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 2002 goto out; 2003 } 2004 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 2005 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 2006 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 2007 (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || 2008 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 2009 (r = sshbuf_put_cstring(b, sshkey_ssh_name(private))) != 0 || 2010 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 2011 (r = sshbuf_put_cstring(b, chost)) != 0 || 2012 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 2013 error("%s: buffer error: %s", __func__, ssh_err(r)); 2014 goto out; 2015 } 2016 2017#ifdef DEBUG_PK 2018 sshbuf_dump(b, stderr); 2019#endif 2020 r = ssh_keysign(private, &sig, &siglen, 2021 sshbuf_ptr(b), sshbuf_len(b)); 2022 if (r != 0) { 2023 error("sign using hostkey %s %s failed", 2024 sshkey_ssh_name(private), fp); 2025 goto out; 2026 } 2027 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 2028 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 2029 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 2030 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 2031 (r = sshpkt_put_cstring(ssh, sshkey_ssh_name(private))) != 0 || 2032 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 2033 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 2034 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 2035 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 2036 (r = sshpkt_send(ssh)) != 0) { 2037 error("%s: packet error: %s", __func__, ssh_err(r)); 2038 goto out; 2039 } 2040 success = 1; 2041 2042 out: 2043 if (sig != NULL) 2044 freezero(sig, siglen); 2045 free(keyblob); 2046 free(lname); 2047 free(fp); 2048 free(chost); 2049 sshkey_free(private); 2050 sshbuf_free(b); 2051 2052 return success; 2053} 2054 2055/* find auth method */ 2056 2057/* 2058 * given auth method name, if configurable options permit this method fill 2059 * in auth_ident field and return true, otherwise return false. 2060 */ 2061static int 2062authmethod_is_enabled(Authmethod *method) 2063{ 2064 if (method == NULL) 2065 return 0; 2066 /* return false if options indicate this method is disabled */ 2067 if (method->enabled == NULL || *method->enabled == 0) 2068 return 0; 2069 /* return false if batch mode is enabled but method needs interactive mode */ 2070 if (method->batch_flag != NULL && *method->batch_flag != 0) 2071 return 0; 2072 return 1; 2073} 2074 2075static Authmethod * 2076authmethod_lookup(const char *name) 2077{ 2078 Authmethod *method = NULL; 2079 if (name != NULL) 2080 for (method = authmethods; method->name != NULL; method++) 2081 if (strcmp(name, method->name) == 0) 2082 return method; 2083 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 2084 return NULL; 2085} 2086 2087/* XXX internal state */ 2088static Authmethod *current = NULL; 2089static char *supported = NULL; 2090static char *preferred = NULL; 2091 2092/* 2093 * Given the authentication method list sent by the server, return the 2094 * next method we should try. If the server initially sends a nil list, 2095 * use a built-in default list. 2096 */ 2097static Authmethod * 2098authmethod_get(char *authlist) 2099{ 2100 char *name = NULL; 2101 u_int next; 2102 2103 /* Use a suitable default if we're passed a nil list. */ 2104 if (authlist == NULL || strlen(authlist) == 0) 2105 authlist = options.preferred_authentications; 2106 2107 if (supported == NULL || strcmp(authlist, supported) != 0) { 2108 debug3("start over, passed a different list %s", authlist); 2109 free(supported); 2110 supported = xstrdup(authlist); 2111 preferred = options.preferred_authentications; 2112 debug3("preferred %s", preferred); 2113 current = NULL; 2114 } else if (current != NULL && authmethod_is_enabled(current)) 2115 return current; 2116 2117 for (;;) { 2118 if ((name = match_list(preferred, supported, &next)) == NULL) { 2119 debug("No more authentication methods to try."); 2120 current = NULL; 2121 return NULL; 2122 } 2123 preferred += next; 2124 debug3("authmethod_lookup %s", name); 2125 debug3("remaining preferred: %s", preferred); 2126 if ((current = authmethod_lookup(name)) != NULL && 2127 authmethod_is_enabled(current)) { 2128 debug3("authmethod_is_enabled %s", name); 2129 debug("Next authentication method: %s", name); 2130 free(name); 2131 return current; 2132 } 2133 free(name); 2134 } 2135} 2136 2137static char * 2138authmethods_get(void) 2139{ 2140 Authmethod *method = NULL; 2141 struct sshbuf *b; 2142 char *list; 2143 int r; 2144 2145 if ((b = sshbuf_new()) == NULL) 2146 fatal("%s: sshbuf_new failed", __func__); 2147 for (method = authmethods; method->name != NULL; method++) { 2148 if (authmethod_is_enabled(method)) { 2149 if ((r = sshbuf_putf(b, "%s%s", 2150 sshbuf_len(b) ? "," : "", method->name)) != 0) 2151 fatal("%s: buffer error: %s", 2152 __func__, ssh_err(r)); 2153 } 2154 } 2155 if ((list = sshbuf_dup_string(b)) == NULL) 2156 fatal("%s: sshbuf_dup_string failed", __func__); 2157 sshbuf_free(b); 2158 return list; 2159} 2160