1 /* $OpenBSD: sshconnect2.c,v 1.322 2020/05/13 09:52:41 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 <stdio.h> 40 #include <string.h> 41 #include <stdarg.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 #include "ssh-sk.h" 76 #include "sk-api.h" 77 78 #ifdef GSSAPI 79 #include "ssh-gss.h" 80 #endif 81 82 /* import */ 83 extern char *client_version_string; 84 extern char *server_version_string; 85 extern Options options; 86 87 /* 88 * SSH2 key exchange 89 */ 90 91 u_char *session_id2 = NULL; 92 u_int session_id2_len = 0; 93 94 char *xxx_host; 95 struct sockaddr *xxx_hostaddr; 96 97 static int 98 verify_host_key_callback(struct sshkey *hostkey, struct ssh *ssh) 99 { 100 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 101 fatal("Host key verification failed."); 102 return 0; 103 } 104 105 static char * 106 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 107 { 108 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 109 size_t maxlen; 110 struct hostkeys *hostkeys; 111 int ktype; 112 u_int i; 113 114 /* Find all hostkeys for this hostname */ 115 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 116 hostkeys = init_hostkeys(); 117 for (i = 0; i < options.num_user_hostfiles; i++) 118 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 119 for (i = 0; i < options.num_system_hostfiles; i++) 120 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 121 122 oavail = avail = xstrdup(options.hostkeyalgorithms); 123 maxlen = strlen(avail) + 1; 124 first = xmalloc(maxlen); 125 last = xmalloc(maxlen); 126 *first = *last = '\0'; 127 128 #define ALG_APPEND(to, from) \ 129 do { \ 130 if (*to != '\0') \ 131 strlcat(to, ",", maxlen); \ 132 strlcat(to, from, maxlen); \ 133 } while (0) 134 135 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 136 if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC) 137 fatal("%s: unknown alg %s", __func__, alg); 138 /* 139 * If we have a @cert-authority marker in known_hosts then 140 * prefer all certificate algorithms. 141 */ 142 if (sshkey_type_is_cert(ktype) && 143 lookup_marker_in_hostkeys(hostkeys, MRK_CA)) { 144 ALG_APPEND(first, alg); 145 continue; 146 } 147 /* If the key appears in known_hosts then prefer it */ 148 if (lookup_key_in_hostkeys_by_type(hostkeys, 149 sshkey_type_plain(ktype), NULL)) { 150 ALG_APPEND(first, alg); 151 continue; 152 } 153 /* Otherwise, put it last */ 154 ALG_APPEND(last, alg); 155 } 156 #undef ALG_APPEND 157 xasprintf(&ret, "%s%s%s", first, 158 (*first == '\0' || *last == '\0') ? "" : ",", last); 159 if (*first != '\0') 160 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 161 162 free(first); 163 free(last); 164 free(hostname); 165 free(oavail); 166 free_hostkeys(hostkeys); 167 168 return ret; 169 } 170 171 void 172 ssh_kex2(struct ssh *ssh, char *host, struct sockaddr *hostaddr, u_short port) 173 { 174 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; 175 char *s, *all_key; 176 int r, use_known_hosts_order = 0; 177 178 xxx_host = host; 179 xxx_hostaddr = hostaddr; 180 181 /* 182 * If the user has not specified HostkeyAlgorithms, or has only 183 * appended or removed algorithms from that list then prefer algorithms 184 * that are in the list that are supported by known_hosts keys. 185 */ 186 if (options.hostkeyalgorithms == NULL || 187 options.hostkeyalgorithms[0] == '-' || 188 options.hostkeyalgorithms[0] == '+') 189 use_known_hosts_order = 1; 190 191 /* Expand or fill in HostkeyAlgorithms */ 192 all_key = sshkey_alg_list(0, 0, 1, ','); 193 if (kex_assemble_names(&options.hostkeyalgorithms, 194 kex_default_pk_alg(), all_key) != 0) 195 fatal("%s: kex_assemble_namelist", __func__); 196 free(all_key); 197 198 if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL) 199 fatal("%s: kex_names_cat", __func__); 200 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s); 201 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 202 compat_cipher_proposal(options.ciphers); 203 myproposal[PROPOSAL_ENC_ALGS_STOC] = 204 compat_cipher_proposal(options.ciphers); 205 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 206 myproposal[PROPOSAL_COMP_ALGS_STOC] = 207 (char *)compression_alg_list(options.compression); 208 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 209 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 210 if (use_known_hosts_order) { 211 /* Query known_hosts and prefer algorithms that appear there */ 212 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 213 compat_pkalg_proposal( 214 order_hostkeyalgs(host, hostaddr, port)); 215 } else { 216 /* Use specified HostkeyAlgorithms exactly */ 217 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 218 compat_pkalg_proposal(options.hostkeyalgorithms); 219 } 220 221 if (options.rekey_limit || options.rekey_interval) 222 ssh_packet_set_rekey_limits(ssh, options.rekey_limit, 223 options.rekey_interval); 224 225 /* start key exchange */ 226 if ((r = kex_setup(ssh, myproposal)) != 0) 227 fatal("kex_setup: %s", ssh_err(r)); 228 #ifdef WITH_OPENSSL 229 ssh->kex->kex[KEX_DH_GRP1_SHA1] = kex_gen_client; 230 ssh->kex->kex[KEX_DH_GRP14_SHA1] = kex_gen_client; 231 ssh->kex->kex[KEX_DH_GRP14_SHA256] = kex_gen_client; 232 ssh->kex->kex[KEX_DH_GRP16_SHA512] = kex_gen_client; 233 ssh->kex->kex[KEX_DH_GRP18_SHA512] = kex_gen_client; 234 ssh->kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 235 ssh->kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 236 # ifdef OPENSSL_HAS_ECC 237 ssh->kex->kex[KEX_ECDH_SHA2] = kex_gen_client; 238 # endif 239 #endif 240 ssh->kex->kex[KEX_C25519_SHA256] = kex_gen_client; 241 ssh->kex->kex[KEX_KEM_SNTRUP4591761X25519_SHA512] = kex_gen_client; 242 ssh->kex->verify_host_key=&verify_host_key_callback; 243 244 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &ssh->kex->done); 245 246 /* remove ext-info from the KEX proposals for rekeying */ 247 myproposal[PROPOSAL_KEX_ALGS] = 248 compat_kex_proposal(options.kex_algorithms); 249 if ((r = kex_prop2buf(ssh->kex->my, myproposal)) != 0) 250 fatal("kex_prop2buf: %s", ssh_err(r)); 251 252 session_id2 = ssh->kex->session_id; 253 session_id2_len = ssh->kex->session_id_len; 254 255 #ifdef DEBUG_KEXDH 256 /* send 1st encrypted/maced/compressed message */ 257 if ((r = sshpkt_start(ssh, SSH2_MSG_IGNORE)) != 0 || 258 (r = sshpkt_put_cstring(ssh, "markus")) != 0 || 259 (r = sshpkt_send(ssh)) != 0 || 260 (r = ssh_packet_write_wait(ssh)) != 0) 261 fatal("%s: %s", __func__, ssh_err(r)); 262 #endif 263 } 264 265 /* 266 * Authenticate user 267 */ 268 269 typedef struct cauthctxt Authctxt; 270 typedef struct cauthmethod Authmethod; 271 typedef struct identity Identity; 272 typedef struct idlist Idlist; 273 274 struct identity { 275 TAILQ_ENTRY(identity) next; 276 int agent_fd; /* >=0 if agent supports key */ 277 struct sshkey *key; /* public/private key */ 278 char *filename; /* comment for agent-only keys */ 279 int tried; 280 int isprivate; /* key points to the private key */ 281 int userprovided; 282 }; 283 TAILQ_HEAD(idlist, identity); 284 285 struct cauthctxt { 286 const char *server_user; 287 const char *local_user; 288 const char *host; 289 const char *service; 290 struct cauthmethod *method; 291 sig_atomic_t success; 292 char *authlist; 293 #ifdef GSSAPI 294 /* gssapi */ 295 gss_OID_set gss_supported_mechs; 296 u_int mech_tried; 297 #endif 298 /* pubkey */ 299 struct idlist keys; 300 int agent_fd; 301 /* hostbased */ 302 Sensitive *sensitive; 303 char *oktypes, *ktypes; 304 const char *active_ktype; 305 /* kbd-interactive */ 306 int info_req_seen; 307 int attempt_kbdint; 308 /* password */ 309 int attempt_passwd; 310 /* generic */ 311 void *methoddata; 312 }; 313 314 struct cauthmethod { 315 char *name; /* string to compare against server's list */ 316 int (*userauth)(struct ssh *ssh); 317 void (*cleanup)(struct ssh *ssh); 318 int *enabled; /* flag in option struct that enables method */ 319 int *batch_flag; /* flag in option struct that disables method */ 320 }; 321 322 static int input_userauth_service_accept(int, u_int32_t, struct ssh *); 323 static int input_userauth_ext_info(int, u_int32_t, struct ssh *); 324 static int input_userauth_success(int, u_int32_t, struct ssh *); 325 static int input_userauth_failure(int, u_int32_t, struct ssh *); 326 static int input_userauth_banner(int, u_int32_t, struct ssh *); 327 static int input_userauth_error(int, u_int32_t, struct ssh *); 328 static int input_userauth_info_req(int, u_int32_t, struct ssh *); 329 static int input_userauth_pk_ok(int, u_int32_t, struct ssh *); 330 static int input_userauth_passwd_changereq(int, u_int32_t, struct ssh *); 331 332 static int userauth_none(struct ssh *); 333 static int userauth_pubkey(struct ssh *); 334 static int userauth_passwd(struct ssh *); 335 static int userauth_kbdint(struct ssh *); 336 static int userauth_hostbased(struct ssh *); 337 338 #ifdef GSSAPI 339 static int userauth_gssapi(struct ssh *); 340 static void userauth_gssapi_cleanup(struct ssh *); 341 static int input_gssapi_response(int type, u_int32_t, struct ssh *); 342 static int input_gssapi_token(int type, u_int32_t, struct ssh *); 343 static int input_gssapi_error(int, u_int32_t, struct ssh *); 344 static int input_gssapi_errtok(int, u_int32_t, struct ssh *); 345 #endif 346 347 void userauth(struct ssh *, char *); 348 349 static void pubkey_cleanup(struct ssh *); 350 static int sign_and_send_pubkey(struct ssh *ssh, Identity *); 351 static void pubkey_prepare(Authctxt *); 352 static void pubkey_reset(Authctxt *); 353 static struct sshkey *load_identity_file(Identity *); 354 355 static Authmethod *authmethod_get(char *authlist); 356 static Authmethod *authmethod_lookup(const char *name); 357 static char *authmethods_get(void); 358 359 Authmethod authmethods[] = { 360 #ifdef GSSAPI 361 {"gssapi-with-mic", 362 userauth_gssapi, 363 userauth_gssapi_cleanup, 364 &options.gss_authentication, 365 NULL}, 366 #endif 367 {"hostbased", 368 userauth_hostbased, 369 NULL, 370 &options.hostbased_authentication, 371 NULL}, 372 {"publickey", 373 userauth_pubkey, 374 NULL, 375 &options.pubkey_authentication, 376 NULL}, 377 {"keyboard-interactive", 378 userauth_kbdint, 379 NULL, 380 &options.kbd_interactive_authentication, 381 &options.batch_mode}, 382 {"password", 383 userauth_passwd, 384 NULL, 385 &options.password_authentication, 386 &options.batch_mode}, 387 {"none", 388 userauth_none, 389 NULL, 390 NULL, 391 NULL}, 392 {NULL, NULL, NULL, NULL, NULL} 393 }; 394 395 void 396 ssh_userauth2(struct ssh *ssh, const char *local_user, 397 const char *server_user, char *host, Sensitive *sensitive) 398 { 399 Authctxt authctxt; 400 int r; 401 402 if (options.challenge_response_authentication) 403 options.kbd_interactive_authentication = 1; 404 if (options.preferred_authentications == NULL) 405 options.preferred_authentications = authmethods_get(); 406 407 /* setup authentication context */ 408 memset(&authctxt, 0, sizeof(authctxt)); 409 authctxt.server_user = server_user; 410 authctxt.local_user = local_user; 411 authctxt.host = host; 412 authctxt.service = "ssh-connection"; /* service name */ 413 authctxt.success = 0; 414 authctxt.method = authmethod_lookup("none"); 415 authctxt.authlist = NULL; 416 authctxt.methoddata = NULL; 417 authctxt.sensitive = sensitive; 418 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 419 authctxt.info_req_seen = 0; 420 authctxt.attempt_kbdint = 0; 421 authctxt.attempt_passwd = 0; 422 #if GSSAPI 423 authctxt.gss_supported_mechs = NULL; 424 authctxt.mech_tried = 0; 425 #endif 426 authctxt.agent_fd = -1; 427 pubkey_prepare(&authctxt); 428 if (authctxt.method == NULL) { 429 fatal("%s: internal error: cannot send userauth none request", 430 __func__); 431 } 432 433 if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 || 434 (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 || 435 (r = sshpkt_send(ssh)) != 0) 436 fatal("%s: %s", __func__, ssh_err(r)); 437 438 ssh->authctxt = &authctxt; 439 ssh_dispatch_init(ssh, &input_userauth_error); 440 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info); 441 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept); 442 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */ 443 pubkey_cleanup(ssh); 444 ssh->authctxt = NULL; 445 446 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 447 448 if (!authctxt.success) 449 fatal("Authentication failed."); 450 debug("Authentication succeeded (%s).", authctxt.method->name); 451 } 452 453 /* ARGSUSED */ 454 static int 455 input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh) 456 { 457 int r; 458 459 if (ssh_packet_remaining(ssh) > 0) { 460 char *reply; 461 462 if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0) 463 goto out; 464 debug2("service_accept: %s", reply); 465 free(reply); 466 } else { 467 debug2("buggy server: service_accept w/o service"); 468 } 469 if ((r = sshpkt_get_end(ssh)) != 0) 470 goto out; 471 debug("SSH2_MSG_SERVICE_ACCEPT received"); 472 473 /* initial userauth request */ 474 userauth_none(ssh); 475 476 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error); 477 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 478 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 479 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 480 r = 0; 481 out: 482 return r; 483 } 484 485 /* ARGSUSED */ 486 static int 487 input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh) 488 { 489 return kex_input_ext_info(type, seqnr, ssh); 490 } 491 492 void 493 userauth(struct ssh *ssh, char *authlist) 494 { 495 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 496 497 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 498 authctxt->method->cleanup(ssh); 499 500 free(authctxt->methoddata); 501 authctxt->methoddata = NULL; 502 if (authlist == NULL) { 503 authlist = authctxt->authlist; 504 } else { 505 free(authctxt->authlist); 506 authctxt->authlist = authlist; 507 } 508 for (;;) { 509 Authmethod *method = authmethod_get(authlist); 510 if (method == NULL) 511 fatal("%s@%s: Permission denied (%s).", 512 authctxt->server_user, authctxt->host, authlist); 513 authctxt->method = method; 514 515 /* reset the per method handler */ 516 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_PER_METHOD_MIN, 517 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 518 519 /* and try new method */ 520 if (method->userauth(ssh) != 0) { 521 debug2("we sent a %s packet, wait for reply", method->name); 522 break; 523 } else { 524 debug2("we did not send a packet, disable method"); 525 method->enabled = NULL; 526 } 527 } 528 } 529 530 /* ARGSUSED */ 531 static int 532 input_userauth_error(int type, u_int32_t seq, struct ssh *ssh) 533 { 534 fatal("%s: bad message during authentication: type %d", __func__, type); 535 return 0; 536 } 537 538 /* ARGSUSED */ 539 static int 540 input_userauth_banner(int type, u_int32_t seq, struct ssh *ssh) 541 { 542 char *msg = NULL; 543 size_t len; 544 int r; 545 546 debug3("%s", __func__); 547 if ((r = sshpkt_get_cstring(ssh, &msg, &len)) != 0 || 548 (r = sshpkt_get_cstring(ssh, NULL, NULL)) != 0) 549 goto out; 550 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) 551 fmprintf(stderr, "%s", msg); 552 r = 0; 553 out: 554 free(msg); 555 return r; 556 } 557 558 /* ARGSUSED */ 559 static int 560 input_userauth_success(int type, u_int32_t seq, struct ssh *ssh) 561 { 562 Authctxt *authctxt = ssh->authctxt; 563 564 if (authctxt == NULL) 565 fatal("%s: no authentication context", __func__); 566 free(authctxt->authlist); 567 authctxt->authlist = NULL; 568 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 569 authctxt->method->cleanup(ssh); 570 free(authctxt->methoddata); 571 authctxt->methoddata = NULL; 572 authctxt->success = 1; /* break out */ 573 return 0; 574 } 575 576 #if 0 577 static int 578 input_userauth_success_unexpected(int type, u_int32_t seq, struct ssh *ssh) 579 { 580 Authctxt *authctxt = ssh->authctxt; 581 582 if (authctxt == NULL) 583 fatal("%s: no authentication context", __func__); 584 585 fatal("Unexpected authentication success during %s.", 586 authctxt->method->name); 587 return 0; 588 } 589 #endif 590 591 /* ARGSUSED */ 592 static int 593 input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh) 594 { 595 Authctxt *authctxt = ssh->authctxt; 596 char *authlist = NULL; 597 u_char partial; 598 599 if (authctxt == NULL) 600 fatal("input_userauth_failure: no authentication context"); 601 602 if (sshpkt_get_cstring(ssh, &authlist, NULL) != 0 || 603 sshpkt_get_u8(ssh, &partial) != 0 || 604 sshpkt_get_end(ssh) != 0) 605 goto out; 606 607 if (partial != 0) { 608 verbose("Authenticated with partial success."); 609 /* reset state */ 610 pubkey_reset(authctxt); 611 } 612 debug("Authentications that can continue: %s", authlist); 613 614 userauth(ssh, authlist); 615 authlist = NULL; 616 out: 617 free(authlist); 618 return 0; 619 } 620 621 /* 622 * Format an identity for logging including filename, key type, fingerprint 623 * and location (agent, etc.). Caller must free. 624 */ 625 static char * 626 format_identity(Identity *id) 627 { 628 char *fp = NULL, *ret = NULL; 629 const char *note = ""; 630 631 if (id->key != NULL) { 632 fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 633 SSH_FP_DEFAULT); 634 } 635 if (id->key) { 636 if ((id->key->flags & SSHKEY_FLAG_EXT) != 0) 637 note = " token"; 638 else if (sshkey_is_sk(id->key)) 639 note = " authenticator"; 640 } 641 xasprintf(&ret, "%s %s%s%s%s%s%s", 642 id->filename, 643 id->key ? sshkey_type(id->key) : "", id->key ? " " : "", 644 fp ? fp : "", 645 id->userprovided ? " explicit" : "", note, 646 id->agent_fd != -1 ? " agent" : ""); 647 free(fp); 648 return ret; 649 } 650 651 /* ARGSUSED */ 652 static int 653 input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh) 654 { 655 Authctxt *authctxt = ssh->authctxt; 656 struct sshkey *key = NULL; 657 Identity *id = NULL; 658 int pktype, found = 0, sent = 0; 659 size_t blen; 660 char *pkalg = NULL, *fp = NULL, *ident = NULL; 661 u_char *pkblob = NULL; 662 int r; 663 664 if (authctxt == NULL) 665 fatal("input_userauth_pk_ok: no authentication context"); 666 667 if ((r = sshpkt_get_cstring(ssh, &pkalg, NULL)) != 0 || 668 (r = sshpkt_get_string(ssh, &pkblob, &blen)) != 0 || 669 (r = sshpkt_get_end(ssh)) != 0) 670 goto done; 671 672 if ((pktype = sshkey_type_from_name(pkalg)) == KEY_UNSPEC) { 673 debug("%s: server sent unknown pkalg %s", __func__, pkalg); 674 goto done; 675 } 676 if ((r = sshkey_from_blob(pkblob, blen, &key)) != 0) { 677 debug("no key from blob. pkalg %s: %s", pkalg, ssh_err(r)); 678 goto done; 679 } 680 if (key->type != pktype) { 681 error("input_userauth_pk_ok: type mismatch " 682 "for decoded key (received %d, expected %d)", 683 key->type, pktype); 684 goto done; 685 } 686 687 /* 688 * search keys in the reverse order, because last candidate has been 689 * moved to the end of the queue. this also avoids confusion by 690 * duplicate keys 691 */ 692 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 693 if (sshkey_equal(key, id->key)) { 694 found = 1; 695 break; 696 } 697 } 698 if (!found || id == NULL) { 699 fp = sshkey_fingerprint(key, options.fingerprint_hash, 700 SSH_FP_DEFAULT); 701 error("%s: server replied with unknown key: %s %s", __func__, 702 sshkey_type(key), fp == NULL ? "<ERROR>" : fp); 703 goto done; 704 } 705 ident = format_identity(id); 706 debug("Server accepts key: %s", ident); 707 sent = sign_and_send_pubkey(ssh, id); 708 r = 0; 709 done: 710 sshkey_free(key); 711 free(ident); 712 free(fp); 713 free(pkalg); 714 free(pkblob); 715 716 /* try another method if we did not send a packet */ 717 if (r == 0 && sent == 0) 718 userauth(ssh, NULL); 719 return r; 720 } 721 722 #ifdef GSSAPI 723 static int 724 userauth_gssapi(struct ssh *ssh) 725 { 726 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 727 Gssctxt *gssctxt = NULL; 728 OM_uint32 min; 729 int r, ok = 0; 730 gss_OID mech = NULL; 731 732 /* Try one GSSAPI method at a time, rather than sending them all at 733 * once. */ 734 735 if (authctxt->gss_supported_mechs == NULL) 736 gss_indicate_mechs(&min, &authctxt->gss_supported_mechs); 737 738 /* Check to see whether the mechanism is usable before we offer it */ 739 while (authctxt->mech_tried < authctxt->gss_supported_mechs->count && 740 !ok) { 741 mech = &authctxt->gss_supported_mechs-> 742 elements[authctxt->mech_tried]; 743 /* My DER encoding requires length<128 */ 744 if (mech->length < 128 && ssh_gssapi_check_mechanism(&gssctxt, 745 mech, authctxt->host)) { 746 ok = 1; /* Mechanism works */ 747 } else { 748 authctxt->mech_tried++; 749 } 750 } 751 752 if (!ok || mech == NULL) 753 return 0; 754 755 authctxt->methoddata=(void *)gssctxt; 756 757 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 758 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 759 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 760 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 761 (r = sshpkt_put_u32(ssh, 1)) != 0 || 762 (r = sshpkt_put_u32(ssh, (mech->length) + 2)) != 0 || 763 (r = sshpkt_put_u8(ssh, SSH_GSS_OIDTYPE)) != 0 || 764 (r = sshpkt_put_u8(ssh, mech->length)) != 0 || 765 (r = sshpkt_put(ssh, mech->elements, mech->length)) != 0 || 766 (r = sshpkt_send(ssh)) != 0) 767 fatal("%s: %s", __func__, ssh_err(r)); 768 769 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 770 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 771 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 772 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 773 774 authctxt->mech_tried++; /* Move along to next candidate */ 775 776 return 1; 777 } 778 779 static void 780 userauth_gssapi_cleanup(struct ssh *ssh) 781 { 782 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 783 Gssctxt *gssctxt = (Gssctxt *)authctxt->methoddata; 784 785 ssh_gssapi_delete_ctx(&gssctxt); 786 authctxt->methoddata = NULL; 787 788 free(authctxt->gss_supported_mechs); 789 authctxt->gss_supported_mechs = NULL; 790 } 791 792 static OM_uint32 793 process_gssapi_token(struct ssh *ssh, gss_buffer_t recv_tok) 794 { 795 Authctxt *authctxt = ssh->authctxt; 796 Gssctxt *gssctxt = authctxt->methoddata; 797 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 798 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 799 gss_buffer_desc gssbuf; 800 OM_uint32 status, ms, flags; 801 int r; 802 803 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 804 recv_tok, &send_tok, &flags); 805 806 if (send_tok.length > 0) { 807 u_char type = GSS_ERROR(status) ? 808 SSH2_MSG_USERAUTH_GSSAPI_ERRTOK : 809 SSH2_MSG_USERAUTH_GSSAPI_TOKEN; 810 811 if ((r = sshpkt_start(ssh, type)) != 0 || 812 (r = sshpkt_put_string(ssh, send_tok.value, 813 send_tok.length)) != 0 || 814 (r = sshpkt_send(ssh)) != 0) 815 fatal("%s: %s", __func__, ssh_err(r)); 816 817 gss_release_buffer(&ms, &send_tok); 818 } 819 820 if (status == GSS_S_COMPLETE) { 821 /* send either complete or MIC, depending on mechanism */ 822 if (!(flags & GSS_C_INTEG_FLAG)) { 823 if ((r = sshpkt_start(ssh, 824 SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE)) != 0 || 825 (r = sshpkt_send(ssh)) != 0) 826 fatal("%s: %s", __func__, ssh_err(r)); 827 } else { 828 struct sshbuf *b; 829 830 if ((b = sshbuf_new()) == NULL) 831 fatal("%s: sshbuf_new failed", __func__); 832 ssh_gssapi_buildmic(b, authctxt->server_user, 833 authctxt->service, "gssapi-with-mic"); 834 835 if ((gssbuf.value = sshbuf_mutable_ptr(b)) == NULL) 836 fatal("%s: sshbuf_mutable_ptr failed", __func__); 837 gssbuf.length = sshbuf_len(b); 838 839 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 840 841 if (!GSS_ERROR(status)) { 842 if ((r = sshpkt_start(ssh, 843 SSH2_MSG_USERAUTH_GSSAPI_MIC)) != 0 || 844 (r = sshpkt_put_string(ssh, mic.value, 845 mic.length)) != 0 || 846 (r = sshpkt_send(ssh)) != 0) 847 fatal("%s: %s", __func__, ssh_err(r)); 848 } 849 850 sshbuf_free(b); 851 gss_release_buffer(&ms, &mic); 852 } 853 } 854 855 return status; 856 } 857 858 /* ARGSUSED */ 859 static int 860 input_gssapi_response(int type, u_int32_t plen, struct ssh *ssh) 861 { 862 Authctxt *authctxt = ssh->authctxt; 863 Gssctxt *gssctxt; 864 size_t oidlen; 865 u_char *oidv = NULL; 866 int r; 867 868 if (authctxt == NULL) 869 fatal("input_gssapi_response: no authentication context"); 870 gssctxt = authctxt->methoddata; 871 872 /* Setup our OID */ 873 if ((r = sshpkt_get_string(ssh, &oidv, &oidlen)) != 0) 874 goto done; 875 876 if (oidlen <= 2 || 877 oidv[0] != SSH_GSS_OIDTYPE || 878 oidv[1] != oidlen - 2) { 879 debug("Badly encoded mechanism OID received"); 880 userauth(ssh, NULL); 881 goto ok; 882 } 883 884 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 885 fatal("Server returned different OID than expected"); 886 887 if ((r = sshpkt_get_end(ssh)) != 0) 888 goto done; 889 890 if (GSS_ERROR(process_gssapi_token(ssh, GSS_C_NO_BUFFER))) { 891 /* Start again with next method on list */ 892 debug("Trying to start again"); 893 userauth(ssh, NULL); 894 goto ok; 895 } 896 ok: 897 r = 0; 898 done: 899 free(oidv); 900 return r; 901 } 902 903 /* ARGSUSED */ 904 static int 905 input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh) 906 { 907 Authctxt *authctxt = ssh->authctxt; 908 gss_buffer_desc recv_tok; 909 u_char *p = NULL; 910 size_t len; 911 OM_uint32 status; 912 int r; 913 914 if (authctxt == NULL) 915 fatal("input_gssapi_response: no authentication context"); 916 917 if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || 918 (r = sshpkt_get_end(ssh)) != 0) 919 goto out; 920 921 recv_tok.value = p; 922 recv_tok.length = len; 923 status = process_gssapi_token(ssh, &recv_tok); 924 925 /* Start again with the next method in the list */ 926 if (GSS_ERROR(status)) { 927 userauth(ssh, NULL); 928 /* ok */ 929 } 930 r = 0; 931 out: 932 free(p); 933 return r; 934 } 935 936 /* ARGSUSED */ 937 static int 938 input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh) 939 { 940 Authctxt *authctxt = ssh->authctxt; 941 Gssctxt *gssctxt; 942 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 943 gss_buffer_desc recv_tok; 944 OM_uint32 ms; 945 u_char *p = NULL; 946 size_t len; 947 int r; 948 949 if (authctxt == NULL) 950 fatal("input_gssapi_response: no authentication context"); 951 gssctxt = authctxt->methoddata; 952 953 if ((r = sshpkt_get_string(ssh, &p, &len)) != 0 || 954 (r = sshpkt_get_end(ssh)) != 0) { 955 free(p); 956 return r; 957 } 958 959 /* Stick it into GSSAPI and see what it says */ 960 recv_tok.value = p; 961 recv_tok.length = len; 962 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 963 &recv_tok, &send_tok, NULL); 964 free(p); 965 gss_release_buffer(&ms, &send_tok); 966 967 /* Server will be returning a failed packet after this one */ 968 return 0; 969 } 970 971 /* ARGSUSED */ 972 static int 973 input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh) 974 { 975 char *msg = NULL; 976 char *lang = NULL; 977 int r; 978 979 if ((r = sshpkt_get_u32(ssh, NULL)) != 0 || /* maj */ 980 (r = sshpkt_get_u32(ssh, NULL)) != 0 || /* min */ 981 (r = sshpkt_get_cstring(ssh, &msg, NULL)) != 0 || 982 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 983 goto out; 984 r = sshpkt_get_end(ssh); 985 debug("Server GSSAPI Error:\n%s", msg); 986 out: 987 free(msg); 988 free(lang); 989 return r; 990 } 991 #endif /* GSSAPI */ 992 993 static int 994 userauth_none(struct ssh *ssh) 995 { 996 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 997 int r; 998 999 /* initial userauth request */ 1000 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1001 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1002 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1003 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1004 (r = sshpkt_send(ssh)) != 0) 1005 fatal("%s: %s", __func__, ssh_err(r)); 1006 return 1; 1007 } 1008 1009 static int 1010 userauth_passwd(struct ssh *ssh) 1011 { 1012 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1013 char *password, *prompt = NULL; 1014 const char *host = options.host_key_alias ? options.host_key_alias : 1015 authctxt->host; 1016 int r; 1017 1018 if (authctxt->attempt_passwd++ >= options.number_of_password_prompts) 1019 return 0; 1020 1021 if (authctxt->attempt_passwd != 1) 1022 error("Permission denied, please try again."); 1023 1024 xasprintf(&prompt, "%s@%s's password: ", authctxt->server_user, host); 1025 password = read_passphrase(prompt, 0); 1026 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1027 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1028 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1029 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1030 (r = sshpkt_put_u8(ssh, 0)) != 0 || 1031 (r = sshpkt_put_cstring(ssh, password)) != 0 || 1032 (r = sshpkt_add_padding(ssh, 64)) != 0 || 1033 (r = sshpkt_send(ssh)) != 0) 1034 fatal("%s: %s", __func__, ssh_err(r)); 1035 1036 free(prompt); 1037 if (password != NULL) 1038 freezero(password, strlen(password)); 1039 1040 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1041 &input_userauth_passwd_changereq); 1042 1043 return 1; 1044 } 1045 1046 /* 1047 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 1048 */ 1049 /* ARGSUSED */ 1050 static int 1051 input_userauth_passwd_changereq(int type, u_int32_t seqnr, struct ssh *ssh) 1052 { 1053 Authctxt *authctxt = ssh->authctxt; 1054 char *info = NULL, *lang = NULL, *password = NULL, *retype = NULL; 1055 char prompt[256]; 1056 const char *host; 1057 int r; 1058 1059 debug2("input_userauth_passwd_changereq"); 1060 1061 if (authctxt == NULL) 1062 fatal("input_userauth_passwd_changereq: " 1063 "no authentication context"); 1064 host = options.host_key_alias ? options.host_key_alias : authctxt->host; 1065 1066 if ((r = sshpkt_get_cstring(ssh, &info, NULL)) != 0 || 1067 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 1068 goto out; 1069 if (strlen(info) > 0) 1070 logit("%s", info); 1071 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1072 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1073 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1074 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1075 (r = sshpkt_put_u8(ssh, 1)) != 0) /* additional info */ 1076 goto out; 1077 1078 snprintf(prompt, sizeof(prompt), 1079 "Enter %.30s@%.128s's old password: ", 1080 authctxt->server_user, host); 1081 password = read_passphrase(prompt, 0); 1082 if ((r = sshpkt_put_cstring(ssh, password)) != 0) 1083 goto out; 1084 1085 freezero(password, strlen(password)); 1086 password = NULL; 1087 while (password == NULL) { 1088 snprintf(prompt, sizeof(prompt), 1089 "Enter %.30s@%.128s's new password: ", 1090 authctxt->server_user, host); 1091 password = read_passphrase(prompt, RP_ALLOW_EOF); 1092 if (password == NULL) { 1093 /* bail out */ 1094 r = 0; 1095 goto out; 1096 } 1097 snprintf(prompt, sizeof(prompt), 1098 "Retype %.30s@%.128s's new password: ", 1099 authctxt->server_user, host); 1100 retype = read_passphrase(prompt, 0); 1101 if (strcmp(password, retype) != 0) { 1102 freezero(password, strlen(password)); 1103 logit("Mismatch; try again, EOF to quit."); 1104 password = NULL; 1105 } 1106 freezero(retype, strlen(retype)); 1107 } 1108 if ((r = sshpkt_put_cstring(ssh, password)) != 0 || 1109 (r = sshpkt_add_padding(ssh, 64)) != 0 || 1110 (r = sshpkt_send(ssh)) != 0) 1111 goto out; 1112 1113 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 1114 &input_userauth_passwd_changereq); 1115 r = 0; 1116 out: 1117 if (password) 1118 freezero(password, strlen(password)); 1119 free(info); 1120 free(lang); 1121 return r; 1122 } 1123 1124 /* 1125 * Select an algorithm for publickey signatures. 1126 * Returns algorithm (caller must free) or NULL if no mutual algorithm found. 1127 * 1128 * Call with ssh==NULL to ignore server-sig-algs extension list and 1129 * only attempt with the key's base signature type. 1130 */ 1131 static char * 1132 key_sig_algorithm(struct ssh *ssh, const struct sshkey *key) 1133 { 1134 char *allowed, *oallowed, *cp, *tmp, *alg = NULL; 1135 1136 /* 1137 * The signature algorithm will only differ from the key algorithm 1138 * for RSA keys/certs and when the server advertises support for 1139 * newer (SHA2) algorithms. 1140 */ 1141 if (ssh == NULL || ssh->kex->server_sig_algs == NULL || 1142 (key->type != KEY_RSA && key->type != KEY_RSA_CERT) || 1143 (key->type == KEY_RSA_CERT && (datafellows & SSH_BUG_SIGTYPE))) { 1144 /* Filter base key signature alg against our configuration */ 1145 return match_list(sshkey_ssh_name(key), 1146 options.pubkey_key_types, NULL); 1147 } 1148 1149 /* 1150 * For RSA keys/certs, since these might have a different sig type: 1151 * find the first entry in PubkeyAcceptedKeyTypes of the right type 1152 * that also appears in the supported signature algorithms list from 1153 * the server. 1154 */ 1155 oallowed = allowed = xstrdup(options.pubkey_key_types); 1156 while ((cp = strsep(&allowed, ",")) != NULL) { 1157 if (sshkey_type_from_name(cp) != key->type) 1158 continue; 1159 tmp = match_list(sshkey_sigalg_by_name(cp), ssh->kex->server_sig_algs, NULL); 1160 if (tmp != NULL) 1161 alg = xstrdup(cp); 1162 free(tmp); 1163 if (alg != NULL) 1164 break; 1165 } 1166 free(oallowed); 1167 return alg; 1168 } 1169 1170 static int 1171 identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 1172 const u_char *data, size_t datalen, u_int compat, const char *alg) 1173 { 1174 struct sshkey *sign_key = NULL, *prv = NULL; 1175 int r = SSH_ERR_INTERNAL_ERROR; 1176 struct notifier_ctx *notifier = NULL; 1177 char *fp = NULL; 1178 1179 *sigp = NULL; 1180 *lenp = 0; 1181 1182 /* The agent supports this key. */ 1183 if (id->key != NULL && id->agent_fd != -1) { 1184 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 1185 data, datalen, alg, compat); 1186 } 1187 1188 /* 1189 * We have already loaded the private key or the private key is 1190 * stored in external hardware. 1191 */ 1192 if (id->key != NULL && 1193 (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))) { 1194 sign_key = id->key; 1195 } else { 1196 /* Load the private key from the file. */ 1197 if ((prv = load_identity_file(id)) == NULL) 1198 return SSH_ERR_KEY_NOT_FOUND; 1199 if (id->key != NULL && !sshkey_equal_public(prv, id->key)) { 1200 error("%s: private key %s contents do not match public", 1201 __func__, id->filename); 1202 r = SSH_ERR_KEY_NOT_FOUND; 1203 goto out; 1204 } 1205 sign_key = prv; 1206 if (sshkey_is_sk(sign_key) && 1207 (sign_key->sk_flags & SSH_SK_USER_PRESENCE_REQD)) { 1208 /* XXX match batch mode should just skip these keys? */ 1209 if ((fp = sshkey_fingerprint(sign_key, 1210 options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) 1211 fatal("%s: sshkey_fingerprint", __func__); 1212 notifier = notify_start(options.batch_mode, 1213 "Confirm user presence for key %s %s", 1214 sshkey_type(sign_key), fp); 1215 free(fp); 1216 } 1217 } 1218 if ((r = sshkey_sign(sign_key, sigp, lenp, data, datalen, 1219 alg, options.sk_provider, compat)) != 0) { 1220 debug("%s: sshkey_sign: %s", __func__, ssh_err(r)); 1221 goto out; 1222 } 1223 /* 1224 * PKCS#11 tokens may not support all signature algorithms, 1225 * so check what we get back. 1226 */ 1227 if ((r = sshkey_check_sigtype(*sigp, *lenp, alg)) != 0) { 1228 debug("%s: sshkey_check_sigtype: %s", __func__, ssh_err(r)); 1229 goto out; 1230 } 1231 /* success */ 1232 r = 0; 1233 out: 1234 notify_complete(notifier); 1235 sshkey_free(prv); 1236 return r; 1237 } 1238 1239 static int 1240 id_filename_matches(Identity *id, Identity *private_id) 1241 { 1242 const char *suffixes[] = { ".pub", "-cert.pub", NULL }; 1243 size_t len = strlen(id->filename), plen = strlen(private_id->filename); 1244 size_t i, slen; 1245 1246 if (strcmp(id->filename, private_id->filename) == 0) 1247 return 1; 1248 for (i = 0; suffixes[i]; i++) { 1249 slen = strlen(suffixes[i]); 1250 if (len > slen && plen == len - slen && 1251 strcmp(id->filename + (len - slen), suffixes[i]) == 0 && 1252 memcmp(id->filename, private_id->filename, plen) == 0) 1253 return 1; 1254 } 1255 return 0; 1256 } 1257 1258 static int 1259 sign_and_send_pubkey(struct ssh *ssh, Identity *id) 1260 { 1261 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1262 struct sshbuf *b = NULL; 1263 Identity *private_id, *sign_id = NULL; 1264 u_char *signature = NULL; 1265 size_t slen = 0, skip = 0; 1266 int r, fallback_sigtype, sent = 0; 1267 char *alg = NULL, *fp = NULL; 1268 const char *loc = ""; 1269 1270 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1271 SSH_FP_DEFAULT)) == NULL) 1272 return 0; 1273 1274 debug3("%s: %s %s", __func__, sshkey_type(id->key), fp); 1275 1276 /* 1277 * If the key is an certificate, try to find a matching private key 1278 * and use it to complete the signature. 1279 * If no such private key exists, fall back to trying the certificate 1280 * key itself in case it has a private half already loaded. 1281 * This will try to set sign_id to the private key that will perform 1282 * the signature. 1283 */ 1284 if (sshkey_is_cert(id->key)) { 1285 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1286 if (sshkey_equal_public(id->key, private_id->key) && 1287 id->key->type != private_id->key->type) { 1288 sign_id = private_id; 1289 break; 1290 } 1291 } 1292 /* 1293 * Exact key matches are preferred, but also allow 1294 * filename matches for non-PKCS#11/agent keys that 1295 * didn't load public keys. This supports the case 1296 * of keeping just a private key file and public 1297 * certificate on disk. 1298 */ 1299 if (sign_id == NULL && 1300 !id->isprivate && id->agent_fd == -1 && 1301 (id->key->flags & SSHKEY_FLAG_EXT) == 0) { 1302 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1303 if (private_id->key == NULL && 1304 id_filename_matches(id, private_id)) { 1305 sign_id = private_id; 1306 break; 1307 } 1308 } 1309 } 1310 if (sign_id != NULL) { 1311 debug2("%s: using private key \"%s\"%s for " 1312 "certificate", __func__, id->filename, 1313 id->agent_fd != -1 ? " from agent" : ""); 1314 } else { 1315 debug("%s: no separate private key for certificate " 1316 "\"%s\"", __func__, id->filename); 1317 } 1318 } 1319 1320 /* 1321 * If the above didn't select another identity to do the signing 1322 * then default to the one we started with. 1323 */ 1324 if (sign_id == NULL) 1325 sign_id = id; 1326 1327 /* assemble and sign data */ 1328 for (fallback_sigtype = 0; fallback_sigtype <= 1; fallback_sigtype++) { 1329 free(alg); 1330 slen = 0; 1331 signature = NULL; 1332 if ((alg = key_sig_algorithm(fallback_sigtype ? NULL : ssh, 1333 id->key)) == NULL) { 1334 error("%s: no mutual signature supported", __func__); 1335 goto out; 1336 } 1337 debug3("%s: signing using %s %s", __func__, alg, fp); 1338 1339 sshbuf_free(b); 1340 if ((b = sshbuf_new()) == NULL) 1341 fatal("%s: sshbuf_new failed", __func__); 1342 if (datafellows & SSH_OLD_SESSIONID) { 1343 if ((r = sshbuf_put(b, session_id2, 1344 session_id2_len)) != 0) { 1345 fatal("%s: sshbuf_put: %s", 1346 __func__, ssh_err(r)); 1347 } 1348 } else { 1349 if ((r = sshbuf_put_string(b, session_id2, 1350 session_id2_len)) != 0) { 1351 fatal("%s: sshbuf_put_string: %s", 1352 __func__, ssh_err(r)); 1353 } 1354 } 1355 skip = sshbuf_len(b); 1356 if ((r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1357 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1358 (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || 1359 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1360 (r = sshbuf_put_u8(b, 1)) != 0 || 1361 (r = sshbuf_put_cstring(b, alg)) != 0 || 1362 (r = sshkey_puts(id->key, b)) != 0) { 1363 fatal("%s: assemble signed data: %s", 1364 __func__, ssh_err(r)); 1365 } 1366 1367 /* generate signature */ 1368 r = identity_sign(sign_id, &signature, &slen, 1369 sshbuf_ptr(b), sshbuf_len(b), datafellows, alg); 1370 if (r == 0) 1371 break; 1372 else if (r == SSH_ERR_KEY_NOT_FOUND) 1373 goto out; /* soft failure */ 1374 else if (r == SSH_ERR_SIGN_ALG_UNSUPPORTED && 1375 !fallback_sigtype) { 1376 if (sign_id->agent_fd != -1) 1377 loc = "agent "; 1378 else if ((sign_id->key->flags & SSHKEY_FLAG_EXT) != 0) 1379 loc = "token "; 1380 logit("%skey %s %s returned incorrect signature type", 1381 loc, sshkey_type(id->key), fp); 1382 continue; 1383 } 1384 error("%s: signing failed for %s \"%s\"%s: %s", __func__, 1385 sshkey_type(sign_id->key), sign_id->filename, 1386 id->agent_fd != -1 ? " from agent" : "", ssh_err(r)); 1387 goto out; 1388 } 1389 if (slen == 0 || signature == NULL) /* shouldn't happen */ 1390 fatal("%s: no signature", __func__); 1391 1392 /* append signature */ 1393 if ((r = sshbuf_put_string(b, signature, slen)) != 0) 1394 fatal("%s: append signature: %s", __func__, ssh_err(r)); 1395 1396 #ifdef DEBUG_PK 1397 sshbuf_dump(b, stderr); 1398 #endif 1399 /* skip session id and packet type */ 1400 if ((r = sshbuf_consume(b, skip + 1)) != 0) 1401 fatal("%s: consume: %s", __func__, ssh_err(r)); 1402 1403 /* put remaining data from buffer into packet */ 1404 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1405 (r = sshpkt_putb(ssh, b)) != 0 || 1406 (r = sshpkt_send(ssh)) != 0) 1407 fatal("%s: enqueue request: %s", __func__, ssh_err(r)); 1408 1409 /* success */ 1410 sent = 1; 1411 1412 out: 1413 free(fp); 1414 free(alg); 1415 sshbuf_free(b); 1416 freezero(signature, slen); 1417 return sent; 1418 } 1419 1420 static int 1421 send_pubkey_test(struct ssh *ssh, Identity *id) 1422 { 1423 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1424 u_char *blob = NULL; 1425 char *alg = NULL; 1426 size_t bloblen; 1427 u_int have_sig = 0; 1428 int sent = 0, r; 1429 1430 if ((alg = key_sig_algorithm(ssh, id->key)) == NULL) { 1431 debug("%s: no mutual signature algorithm", __func__); 1432 goto out; 1433 } 1434 1435 if ((r = sshkey_to_blob(id->key, &blob, &bloblen)) != 0) { 1436 /* we cannot handle this key */ 1437 debug3("%s: cannot handle key", __func__); 1438 goto out; 1439 } 1440 /* register callback for USERAUTH_PK_OK message */ 1441 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1442 1443 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1444 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1445 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1446 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1447 (r = sshpkt_put_u8(ssh, have_sig)) != 0 || 1448 (r = sshpkt_put_cstring(ssh, alg)) != 0 || 1449 (r = sshpkt_put_string(ssh, blob, bloblen)) != 0 || 1450 (r = sshpkt_send(ssh)) != 0) 1451 fatal("%s: %s", __func__, ssh_err(r)); 1452 sent = 1; 1453 1454 out: 1455 free(alg); 1456 free(blob); 1457 return sent; 1458 } 1459 1460 static struct sshkey * 1461 load_identity_file(Identity *id) 1462 { 1463 struct sshkey *private = NULL; 1464 char prompt[300], *passphrase, *comment; 1465 int r, quit = 0, i; 1466 struct stat st; 1467 1468 if (stat(id->filename, &st) == -1) { 1469 (id->userprovided ? logit : debug3)("no such identity: %s: %s", 1470 id->filename, strerror(errno)); 1471 return NULL; 1472 } 1473 snprintf(prompt, sizeof prompt, 1474 "Enter passphrase for key '%.100s': ", id->filename); 1475 for (i = 0; i <= options.number_of_password_prompts; i++) { 1476 if (i == 0) 1477 passphrase = ""; 1478 else { 1479 passphrase = read_passphrase(prompt, 0); 1480 if (*passphrase == '\0') { 1481 debug2("no passphrase given, try next key"); 1482 free(passphrase); 1483 break; 1484 } 1485 } 1486 switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename, 1487 passphrase, &private, &comment))) { 1488 case 0: 1489 break; 1490 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1491 if (options.batch_mode) { 1492 quit = 1; 1493 break; 1494 } 1495 if (i != 0) 1496 debug2("bad passphrase given, try again..."); 1497 break; 1498 case SSH_ERR_SYSTEM_ERROR: 1499 if (errno == ENOENT) { 1500 debug2("Load key \"%s\": %s", 1501 id->filename, ssh_err(r)); 1502 quit = 1; 1503 break; 1504 } 1505 /* FALLTHROUGH */ 1506 default: 1507 error("Load key \"%s\": %s", id->filename, ssh_err(r)); 1508 quit = 1; 1509 break; 1510 } 1511 if (private != NULL && sshkey_is_sk(private) && 1512 options.sk_provider == NULL) { 1513 debug("key \"%s\" is an authenticator-hosted key, " 1514 "but no provider specified", id->filename); 1515 sshkey_free(private); 1516 private = NULL; 1517 quit = 1; 1518 } 1519 if (!quit && private != NULL && id->agent_fd == -1 && 1520 !(id->key && id->isprivate)) 1521 maybe_add_key_to_agent(id->filename, private, comment, 1522 passphrase); 1523 if (i > 0) 1524 freezero(passphrase, strlen(passphrase)); 1525 free(comment); 1526 if (private != NULL || quit) 1527 break; 1528 } 1529 return private; 1530 } 1531 1532 static int 1533 key_type_allowed_by_config(struct sshkey *key) 1534 { 1535 if (match_pattern_list(sshkey_ssh_name(key), 1536 options.pubkey_key_types, 0) == 1) 1537 return 1; 1538 1539 /* RSA keys/certs might be allowed by alternate signature types */ 1540 switch (key->type) { 1541 case KEY_RSA: 1542 if (match_pattern_list("rsa-sha2-512", 1543 options.pubkey_key_types, 0) == 1) 1544 return 1; 1545 if (match_pattern_list("rsa-sha2-256", 1546 options.pubkey_key_types, 0) == 1) 1547 return 1; 1548 break; 1549 case KEY_RSA_CERT: 1550 if (match_pattern_list("rsa-sha2-512-cert-v01@openssh.com", 1551 options.pubkey_key_types, 0) == 1) 1552 return 1; 1553 if (match_pattern_list("rsa-sha2-256-cert-v01@openssh.com", 1554 options.pubkey_key_types, 0) == 1) 1555 return 1; 1556 break; 1557 } 1558 return 0; 1559 } 1560 1561 1562 /* 1563 * try keys in the following order: 1564 * 1. certificates listed in the config file 1565 * 2. other input certificates 1566 * 3. agent keys that are found in the config file 1567 * 4. other agent keys 1568 * 5. keys that are only listed in the config file 1569 */ 1570 static void 1571 pubkey_prepare(Authctxt *authctxt) 1572 { 1573 struct identity *id, *id2, *tmp; 1574 struct idlist agent, files, *preferred; 1575 struct sshkey *key; 1576 int agent_fd = -1, i, r, found; 1577 size_t j; 1578 struct ssh_identitylist *idlist; 1579 char *ident; 1580 1581 TAILQ_INIT(&agent); /* keys from the agent */ 1582 TAILQ_INIT(&files); /* keys from the config file */ 1583 preferred = &authctxt->keys; 1584 TAILQ_INIT(preferred); /* preferred order of keys */ 1585 1586 /* list of keys stored in the filesystem and PKCS#11 */ 1587 for (i = 0; i < options.num_identity_files; i++) { 1588 key = options.identity_keys[i]; 1589 if (key && key->cert && 1590 key->cert->type != SSH2_CERT_TYPE_USER) { 1591 debug("%s: ignoring certificate %s: not a user " 1592 "certificate", __func__, 1593 options.identity_files[i]); 1594 continue; 1595 } 1596 if (key && sshkey_is_sk(key) && options.sk_provider == NULL) { 1597 debug("%s: ignoring authenticator-hosted key %s as no " 1598 "SecurityKeyProvider has been specified", 1599 __func__, options.identity_files[i]); 1600 continue; 1601 } 1602 options.identity_keys[i] = NULL; 1603 id = xcalloc(1, sizeof(*id)); 1604 id->agent_fd = -1; 1605 id->key = key; 1606 id->filename = xstrdup(options.identity_files[i]); 1607 id->userprovided = options.identity_file_userprovided[i]; 1608 TAILQ_INSERT_TAIL(&files, id, next); 1609 } 1610 /* list of certificates specified by user */ 1611 for (i = 0; i < options.num_certificate_files; i++) { 1612 key = options.certificates[i]; 1613 if (!sshkey_is_cert(key) || key->cert == NULL || 1614 key->cert->type != SSH2_CERT_TYPE_USER) { 1615 debug("%s: ignoring certificate %s: not a user " 1616 "certificate", __func__, 1617 options.identity_files[i]); 1618 continue; 1619 } 1620 if (key && sshkey_is_sk(key) && options.sk_provider == NULL) { 1621 debug("%s: ignoring authenticator-hosted key " 1622 "certificate %s as no " 1623 "SecurityKeyProvider has been specified", 1624 __func__, options.identity_files[i]); 1625 continue; 1626 } 1627 id = xcalloc(1, sizeof(*id)); 1628 id->agent_fd = -1; 1629 id->key = key; 1630 id->filename = xstrdup(options.certificate_files[i]); 1631 id->userprovided = options.certificate_file_userprovided[i]; 1632 TAILQ_INSERT_TAIL(preferred, id, next); 1633 } 1634 /* list of keys supported by the agent */ 1635 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1636 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1637 debug("%s: ssh_get_authentication_socket: %s", 1638 __func__, ssh_err(r)); 1639 } else if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 1640 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1641 debug("%s: ssh_fetch_identitylist: %s", 1642 __func__, ssh_err(r)); 1643 close(agent_fd); 1644 } else { 1645 for (j = 0; j < idlist->nkeys; j++) { 1646 found = 0; 1647 TAILQ_FOREACH(id, &files, next) { 1648 /* 1649 * agent keys from the config file are 1650 * preferred 1651 */ 1652 if (sshkey_equal(idlist->keys[j], id->key)) { 1653 TAILQ_REMOVE(&files, id, next); 1654 TAILQ_INSERT_TAIL(preferred, id, next); 1655 id->agent_fd = agent_fd; 1656 found = 1; 1657 break; 1658 } 1659 } 1660 if (!found && !options.identities_only) { 1661 id = xcalloc(1, sizeof(*id)); 1662 /* XXX "steals" key/comment from idlist */ 1663 id->key = idlist->keys[j]; 1664 id->filename = idlist->comments[j]; 1665 idlist->keys[j] = NULL; 1666 idlist->comments[j] = NULL; 1667 id->agent_fd = agent_fd; 1668 TAILQ_INSERT_TAIL(&agent, id, next); 1669 } 1670 } 1671 ssh_free_identitylist(idlist); 1672 /* append remaining agent keys */ 1673 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1674 TAILQ_REMOVE(&agent, id, next); 1675 TAILQ_INSERT_TAIL(preferred, id, next); 1676 } 1677 authctxt->agent_fd = agent_fd; 1678 } 1679 /* Prefer PKCS11 keys that are explicitly listed */ 1680 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1681 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1682 continue; 1683 found = 0; 1684 TAILQ_FOREACH(id2, &files, next) { 1685 if (id2->key == NULL || 1686 (id2->key->flags & SSHKEY_FLAG_EXT) != 0) 1687 continue; 1688 if (sshkey_equal(id->key, id2->key)) { 1689 TAILQ_REMOVE(&files, id, next); 1690 TAILQ_INSERT_TAIL(preferred, id, next); 1691 found = 1; 1692 break; 1693 } 1694 } 1695 /* If IdentitiesOnly set and key not found then don't use it */ 1696 if (!found && options.identities_only) { 1697 TAILQ_REMOVE(&files, id, next); 1698 freezero(id, sizeof(*id)); 1699 } 1700 } 1701 /* append remaining keys from the config file */ 1702 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1703 TAILQ_REMOVE(&files, id, next); 1704 TAILQ_INSERT_TAIL(preferred, id, next); 1705 } 1706 /* finally, filter by PubkeyAcceptedKeyTypes */ 1707 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1708 if (id->key != NULL && !key_type_allowed_by_config(id->key)) { 1709 debug("Skipping %s key %s - " 1710 "not in PubkeyAcceptedKeyTypes", 1711 sshkey_ssh_name(id->key), id->filename); 1712 TAILQ_REMOVE(preferred, id, next); 1713 sshkey_free(id->key); 1714 free(id->filename); 1715 memset(id, 0, sizeof(*id)); 1716 continue; 1717 } 1718 } 1719 /* List the keys we plan on using */ 1720 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1721 ident = format_identity(id); 1722 debug("Will attempt key: %s", ident); 1723 free(ident); 1724 } 1725 debug2("%s: done", __func__); 1726 } 1727 1728 static void 1729 pubkey_cleanup(struct ssh *ssh) 1730 { 1731 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1732 Identity *id; 1733 1734 if (authctxt->agent_fd != -1) { 1735 ssh_close_authentication_socket(authctxt->agent_fd); 1736 authctxt->agent_fd = -1; 1737 } 1738 for (id = TAILQ_FIRST(&authctxt->keys); id; 1739 id = TAILQ_FIRST(&authctxt->keys)) { 1740 TAILQ_REMOVE(&authctxt->keys, id, next); 1741 sshkey_free(id->key); 1742 free(id->filename); 1743 free(id); 1744 } 1745 } 1746 1747 static void 1748 pubkey_reset(Authctxt *authctxt) 1749 { 1750 Identity *id; 1751 1752 TAILQ_FOREACH(id, &authctxt->keys, next) 1753 id->tried = 0; 1754 } 1755 1756 static int 1757 try_identity(Identity *id) 1758 { 1759 if (!id->key) 1760 return (0); 1761 if (sshkey_type_plain(id->key->type) == KEY_RSA && 1762 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1763 debug("Skipped %s key %s for RSA/MD5 server", 1764 sshkey_type(id->key), id->filename); 1765 return (0); 1766 } 1767 return 1; 1768 } 1769 1770 static int 1771 userauth_pubkey(struct ssh *ssh) 1772 { 1773 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1774 Identity *id; 1775 int sent = 0; 1776 char *ident; 1777 1778 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1779 if (id->tried++) 1780 return (0); 1781 /* move key to the end of the queue */ 1782 TAILQ_REMOVE(&authctxt->keys, id, next); 1783 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1784 /* 1785 * send a test message if we have the public key. for 1786 * encrypted keys we cannot do this and have to load the 1787 * private key instead 1788 */ 1789 if (id->key != NULL) { 1790 if (try_identity(id)) { 1791 ident = format_identity(id); 1792 debug("Offering public key: %s", ident); 1793 free(ident); 1794 sent = send_pubkey_test(ssh, id); 1795 } 1796 } else { 1797 debug("Trying private key: %s", id->filename); 1798 id->key = load_identity_file(id); 1799 if (id->key != NULL) { 1800 if (try_identity(id)) { 1801 id->isprivate = 1; 1802 sent = sign_and_send_pubkey(ssh, id); 1803 } 1804 sshkey_free(id->key); 1805 id->key = NULL; 1806 id->isprivate = 0; 1807 } 1808 } 1809 if (sent) 1810 return (sent); 1811 } 1812 return (0); 1813 } 1814 1815 /* 1816 * Send userauth request message specifying keyboard-interactive method. 1817 */ 1818 static int 1819 userauth_kbdint(struct ssh *ssh) 1820 { 1821 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 1822 int r; 1823 1824 if (authctxt->attempt_kbdint++ >= options.number_of_password_prompts) 1825 return 0; 1826 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1827 if (authctxt->attempt_kbdint > 1 && !authctxt->info_req_seen) { 1828 debug3("userauth_kbdint: disable: no info_req_seen"); 1829 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1830 return 0; 1831 } 1832 1833 debug2("userauth_kbdint"); 1834 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1835 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1836 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1837 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1838 (r = sshpkt_put_cstring(ssh, "")) != 0 || /* lang */ 1839 (r = sshpkt_put_cstring(ssh, options.kbd_interactive_devices ? 1840 options.kbd_interactive_devices : "")) != 0 || 1841 (r = sshpkt_send(ssh)) != 0) 1842 fatal("%s: %s", __func__, ssh_err(r)); 1843 1844 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1845 return 1; 1846 } 1847 1848 /* 1849 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1850 */ 1851 static int 1852 input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh) 1853 { 1854 Authctxt *authctxt = ssh->authctxt; 1855 char *name = NULL, *inst = NULL, *lang = NULL, *prompt = NULL; 1856 char *response = NULL; 1857 u_char echo = 0; 1858 u_int num_prompts, i; 1859 int r; 1860 1861 debug2("input_userauth_info_req"); 1862 1863 if (authctxt == NULL) 1864 fatal("input_userauth_info_req: no authentication context"); 1865 1866 authctxt->info_req_seen = 1; 1867 1868 if ((r = sshpkt_get_cstring(ssh, &name, NULL)) != 0 || 1869 (r = sshpkt_get_cstring(ssh, &inst, NULL)) != 0 || 1870 (r = sshpkt_get_cstring(ssh, &lang, NULL)) != 0) 1871 goto out; 1872 if (strlen(name) > 0) 1873 logit("%s", name); 1874 if (strlen(inst) > 0) 1875 logit("%s", inst); 1876 1877 if ((r = sshpkt_get_u32(ssh, &num_prompts)) != 0) 1878 goto out; 1879 /* 1880 * Begin to build info response packet based on prompts requested. 1881 * We commit to providing the correct number of responses, so if 1882 * further on we run into a problem that prevents this, we have to 1883 * be sure and clean this up and send a correct error response. 1884 */ 1885 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_INFO_RESPONSE)) != 0 || 1886 (r = sshpkt_put_u32(ssh, num_prompts)) != 0) 1887 goto out; 1888 1889 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1890 for (i = 0; i < num_prompts; i++) { 1891 if ((r = sshpkt_get_cstring(ssh, &prompt, NULL)) != 0 || 1892 (r = sshpkt_get_u8(ssh, &echo)) != 0) 1893 goto out; 1894 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1895 if ((r = sshpkt_put_cstring(ssh, response)) != 0) 1896 goto out; 1897 freezero(response, strlen(response)); 1898 free(prompt); 1899 response = prompt = NULL; 1900 } 1901 /* done with parsing incoming message. */ 1902 if ((r = sshpkt_get_end(ssh)) != 0 || 1903 (r = sshpkt_add_padding(ssh, 64)) != 0) 1904 goto out; 1905 r = sshpkt_send(ssh); 1906 out: 1907 if (response) 1908 freezero(response, strlen(response)); 1909 free(prompt); 1910 free(name); 1911 free(inst); 1912 free(lang); 1913 return r; 1914 } 1915 1916 static int 1917 ssh_keysign(struct ssh *ssh, struct sshkey *key, u_char **sigp, size_t *lenp, 1918 const u_char *data, size_t datalen) 1919 { 1920 struct sshbuf *b; 1921 struct stat st; 1922 pid_t pid; 1923 int r, to[2], from[2], status; 1924 int sock = ssh_packet_get_connection_in(ssh); 1925 u_char rversion = 0, version = 2; 1926 void (*osigchld)(int); 1927 1928 *sigp = NULL; 1929 *lenp = 0; 1930 1931 if (stat(_PATH_SSH_KEY_SIGN, &st) == -1) { 1932 error("%s: not installed: %s", __func__, strerror(errno)); 1933 return -1; 1934 } 1935 if (fflush(stdout) != 0) { 1936 error("%s: fflush: %s", __func__, strerror(errno)); 1937 return -1; 1938 } 1939 if (pipe(to) == -1) { 1940 error("%s: pipe: %s", __func__, strerror(errno)); 1941 return -1; 1942 } 1943 if (pipe(from) == -1) { 1944 error("%s: pipe: %s", __func__, strerror(errno)); 1945 return -1; 1946 } 1947 if ((pid = fork()) == -1) { 1948 error("%s: fork: %s", __func__, strerror(errno)); 1949 return -1; 1950 } 1951 osigchld = ssh_signal(SIGCHLD, SIG_DFL); 1952 if (pid == 0) { 1953 close(from[0]); 1954 if (dup2(from[1], STDOUT_FILENO) == -1) 1955 fatal("%s: dup2: %s", __func__, strerror(errno)); 1956 close(to[1]); 1957 if (dup2(to[0], STDIN_FILENO) == -1) 1958 fatal("%s: dup2: %s", __func__, strerror(errno)); 1959 close(from[1]); 1960 close(to[0]); 1961 1962 if (dup2(sock, STDERR_FILENO + 1) == -1) 1963 fatal("%s: dup2: %s", __func__, strerror(errno)); 1964 sock = STDERR_FILENO + 1; 1965 fcntl(sock, F_SETFD, 0); /* keep the socket on exec */ 1966 closefrom(sock + 1); 1967 1968 debug3("%s: [child] pid=%ld, exec %s", 1969 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1970 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL); 1971 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1972 strerror(errno)); 1973 } 1974 close(from[1]); 1975 close(to[0]); 1976 sock = STDERR_FILENO + 1; 1977 1978 if ((b = sshbuf_new()) == NULL) 1979 fatal("%s: sshbuf_new failed", __func__); 1980 /* send # of sock, data to be signed */ 1981 if ((r = sshbuf_put_u32(b, sock)) != 0 || 1982 (r = sshbuf_put_string(b, data, datalen)) != 0) 1983 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1984 if (ssh_msg_send(to[1], version, b) == -1) 1985 fatal("%s: couldn't send request", __func__); 1986 sshbuf_reset(b); 1987 r = ssh_msg_recv(from[0], b); 1988 close(from[0]); 1989 close(to[1]); 1990 if (r < 0) { 1991 error("%s: no reply", __func__); 1992 goto fail; 1993 } 1994 1995 errno = 0; 1996 while (waitpid(pid, &status, 0) == -1) { 1997 if (errno != EINTR) { 1998 error("%s: waitpid %ld: %s", 1999 __func__, (long)pid, strerror(errno)); 2000 goto fail; 2001 } 2002 } 2003 if (!WIFEXITED(status)) { 2004 error("%s: exited abnormally", __func__); 2005 goto fail; 2006 } 2007 if (WEXITSTATUS(status) != 0) { 2008 error("%s: exited with status %d", 2009 __func__, WEXITSTATUS(status)); 2010 goto fail; 2011 } 2012 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 2013 error("%s: buffer error: %s", __func__, ssh_err(r)); 2014 goto fail; 2015 } 2016 if (rversion != version) { 2017 error("%s: bad version", __func__); 2018 goto fail; 2019 } 2020 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 2021 error("%s: buffer error: %s", __func__, ssh_err(r)); 2022 fail: 2023 ssh_signal(SIGCHLD, osigchld); 2024 sshbuf_free(b); 2025 return -1; 2026 } 2027 ssh_signal(SIGCHLD, osigchld); 2028 sshbuf_free(b); 2029 2030 return 0; 2031 } 2032 2033 static int 2034 userauth_hostbased(struct ssh *ssh) 2035 { 2036 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 2037 struct sshkey *private = NULL; 2038 struct sshbuf *b = NULL; 2039 u_char *sig = NULL, *keyblob = NULL; 2040 char *fp = NULL, *chost = NULL, *lname = NULL; 2041 size_t siglen = 0, keylen = 0; 2042 int i, r, success = 0; 2043 2044 if (authctxt->ktypes == NULL) { 2045 authctxt->oktypes = xstrdup(options.hostbased_key_types); 2046 authctxt->ktypes = authctxt->oktypes; 2047 } 2048 2049 /* 2050 * Work through each listed type pattern in HostbasedKeyTypes, 2051 * trying each hostkey that matches the type in turn. 2052 */ 2053 for (;;) { 2054 if (authctxt->active_ktype == NULL) 2055 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 2056 if (authctxt->active_ktype == NULL || 2057 *authctxt->active_ktype == '\0') 2058 break; 2059 debug3("%s: trying key type %s", __func__, 2060 authctxt->active_ktype); 2061 2062 /* check for a useful key */ 2063 private = NULL; 2064 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 2065 if (authctxt->sensitive->keys[i] == NULL || 2066 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 2067 continue; 2068 if (match_pattern_list( 2069 sshkey_ssh_name(authctxt->sensitive->keys[i]), 2070 authctxt->active_ktype, 0) != 1) 2071 continue; 2072 /* we take and free the key */ 2073 private = authctxt->sensitive->keys[i]; 2074 authctxt->sensitive->keys[i] = NULL; 2075 break; 2076 } 2077 /* Found one */ 2078 if (private != NULL) 2079 break; 2080 /* No more keys of this type; advance */ 2081 authctxt->active_ktype = NULL; 2082 } 2083 if (private == NULL) { 2084 free(authctxt->oktypes); 2085 authctxt->oktypes = authctxt->ktypes = NULL; 2086 authctxt->active_ktype = NULL; 2087 debug("No more client hostkeys for hostbased authentication."); 2088 goto out; 2089 } 2090 2091 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 2092 SSH_FP_DEFAULT)) == NULL) { 2093 error("%s: sshkey_fingerprint failed", __func__); 2094 goto out; 2095 } 2096 debug("%s: trying hostkey %s %s", 2097 __func__, sshkey_ssh_name(private), fp); 2098 2099 /* figure out a name for the client host */ 2100 lname = get_local_name(ssh_packet_get_connection_in(ssh)); 2101 if (lname == NULL) { 2102 error("%s: cannot get local ipaddr/name", __func__); 2103 goto out; 2104 } 2105 2106 /* XXX sshbuf_put_stringf? */ 2107 xasprintf(&chost, "%s.", lname); 2108 debug2("%s: chost %s", __func__, chost); 2109 2110 /* construct data */ 2111 if ((b = sshbuf_new()) == NULL) { 2112 error("%s: sshbuf_new failed", __func__); 2113 goto out; 2114 } 2115 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 2116 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 2117 goto out; 2118 } 2119 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 2120 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 2121 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 2122 (r = sshbuf_put_cstring(b, authctxt->service)) != 0 || 2123 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 2124 (r = sshbuf_put_cstring(b, sshkey_ssh_name(private))) != 0 || 2125 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 2126 (r = sshbuf_put_cstring(b, chost)) != 0 || 2127 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 2128 error("%s: buffer error: %s", __func__, ssh_err(r)); 2129 goto out; 2130 } 2131 2132 #ifdef DEBUG_PK 2133 sshbuf_dump(b, stderr); 2134 #endif 2135 if ((r = ssh_keysign(ssh, private, &sig, &siglen, 2136 sshbuf_ptr(b), sshbuf_len(b))) != 0) { 2137 error("sign using hostkey %s %s failed", 2138 sshkey_ssh_name(private), fp); 2139 goto out; 2140 } 2141 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 2142 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 2143 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 2144 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 2145 (r = sshpkt_put_cstring(ssh, sshkey_ssh_name(private))) != 0 || 2146 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 2147 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 2148 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 2149 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 2150 (r = sshpkt_send(ssh)) != 0) { 2151 error("%s: packet error: %s", __func__, ssh_err(r)); 2152 goto out; 2153 } 2154 success = 1; 2155 2156 out: 2157 if (sig != NULL) 2158 freezero(sig, siglen); 2159 free(keyblob); 2160 free(lname); 2161 free(fp); 2162 free(chost); 2163 sshkey_free(private); 2164 sshbuf_free(b); 2165 2166 return success; 2167 } 2168 2169 /* find auth method */ 2170 2171 /* 2172 * given auth method name, if configurable options permit this method fill 2173 * in auth_ident field and return true, otherwise return false. 2174 */ 2175 static int 2176 authmethod_is_enabled(Authmethod *method) 2177 { 2178 if (method == NULL) 2179 return 0; 2180 /* return false if options indicate this method is disabled */ 2181 if (method->enabled == NULL || *method->enabled == 0) 2182 return 0; 2183 /* return false if batch mode is enabled but method needs interactive mode */ 2184 if (method->batch_flag != NULL && *method->batch_flag != 0) 2185 return 0; 2186 return 1; 2187 } 2188 2189 static Authmethod * 2190 authmethod_lookup(const char *name) 2191 { 2192 Authmethod *method = NULL; 2193 if (name != NULL) 2194 for (method = authmethods; method->name != NULL; method++) 2195 if (strcmp(name, method->name) == 0) 2196 return method; 2197 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 2198 return NULL; 2199 } 2200 2201 /* XXX internal state */ 2202 static Authmethod *current = NULL; 2203 static char *supported = NULL; 2204 static char *preferred = NULL; 2205 2206 /* 2207 * Given the authentication method list sent by the server, return the 2208 * next method we should try. If the server initially sends a nil list, 2209 * use a built-in default list. 2210 */ 2211 static Authmethod * 2212 authmethod_get(char *authlist) 2213 { 2214 char *name = NULL; 2215 u_int next; 2216 2217 /* Use a suitable default if we're passed a nil list. */ 2218 if (authlist == NULL || strlen(authlist) == 0) 2219 authlist = options.preferred_authentications; 2220 2221 if (supported == NULL || strcmp(authlist, supported) != 0) { 2222 debug3("start over, passed a different list %s", authlist); 2223 free(supported); 2224 supported = xstrdup(authlist); 2225 preferred = options.preferred_authentications; 2226 debug3("preferred %s", preferred); 2227 current = NULL; 2228 } else if (current != NULL && authmethod_is_enabled(current)) 2229 return current; 2230 2231 for (;;) { 2232 if ((name = match_list(preferred, supported, &next)) == NULL) { 2233 debug("No more authentication methods to try."); 2234 current = NULL; 2235 return NULL; 2236 } 2237 preferred += next; 2238 debug3("authmethod_lookup %s", name); 2239 debug3("remaining preferred: %s", preferred); 2240 if ((current = authmethod_lookup(name)) != NULL && 2241 authmethod_is_enabled(current)) { 2242 debug3("authmethod_is_enabled %s", name); 2243 debug("Next authentication method: %s", name); 2244 free(name); 2245 return current; 2246 } 2247 free(name); 2248 } 2249 } 2250 2251 static char * 2252 authmethods_get(void) 2253 { 2254 Authmethod *method = NULL; 2255 struct sshbuf *b; 2256 char *list; 2257 int r; 2258 2259 if ((b = sshbuf_new()) == NULL) 2260 fatal("%s: sshbuf_new failed", __func__); 2261 for (method = authmethods; method->name != NULL; method++) { 2262 if (authmethod_is_enabled(method)) { 2263 if ((r = sshbuf_putf(b, "%s%s", 2264 sshbuf_len(b) ? "," : "", method->name)) != 0) 2265 fatal("%s: buffer error: %s", 2266 __func__, ssh_err(r)); 2267 } 2268 } 2269 if ((list = sshbuf_dup_string(b)) == NULL) 2270 fatal("%s: sshbuf_dup_string failed", __func__); 2271 sshbuf_free(b); 2272 return list; 2273 } 2274