1 /* $OpenBSD: sshconnect2.c,v 1.264 2017/06/14 00:31:38 dtucker Exp $ */ 2 /* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * Copyright (c) 2008 Damien Miller. All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/types.h> 28 #include <sys/socket.h> 29 #include <sys/wait.h> 30 #include <sys/queue.h> 31 #include <sys/stat.h> 32 33 #include <errno.h> 34 #include <fcntl.h> 35 #include <netdb.h> 36 #include <stdio.h> 37 #include <string.h> 38 #include <signal.h> 39 #include <pwd.h> 40 #include <unistd.h> 41 #include <vis.h> 42 43 #include "xmalloc.h" 44 #include "ssh.h" 45 #include "ssh2.h" 46 #include "buffer.h" 47 #include "packet.h" 48 #include "compat.h" 49 #include "cipher.h" 50 #include "key.h" 51 #include "kex.h" 52 #include "myproposal.h" 53 #include "sshconnect.h" 54 #include "authfile.h" 55 #include "dh.h" 56 #include "authfd.h" 57 #include "log.h" 58 #include "misc.h" 59 #include "readconf.h" 60 #include "match.h" 61 #include "dispatch.h" 62 #include "canohost.h" 63 #include "msg.h" 64 #include "pathnames.h" 65 #include "uidswap.h" 66 #include "hostfile.h" 67 #include "ssherr.h" 68 #include "utf8.h" 69 70 #ifdef GSSAPI 71 #include "ssh-gss.h" 72 #endif 73 74 /* import */ 75 extern char *client_version_string; 76 extern char *server_version_string; 77 extern Options options; 78 79 /* 80 * SSH2 key exchange 81 */ 82 83 u_char *session_id2 = NULL; 84 u_int session_id2_len = 0; 85 86 char *xxx_host; 87 struct sockaddr *xxx_hostaddr; 88 89 static int 90 verify_host_key_callback(struct sshkey *hostkey, struct ssh *ssh) 91 { 92 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 93 fatal("Host key verification failed."); 94 return 0; 95 } 96 97 static char * 98 order_hostkeyalgs(char *host, struct sockaddr *hostaddr, u_short port) 99 { 100 char *oavail, *avail, *first, *last, *alg, *hostname, *ret; 101 size_t maxlen; 102 struct hostkeys *hostkeys; 103 int ktype; 104 u_int i; 105 106 /* Find all hostkeys for this hostname */ 107 get_hostfile_hostname_ipaddr(host, hostaddr, port, &hostname, NULL); 108 hostkeys = init_hostkeys(); 109 for (i = 0; i < options.num_user_hostfiles; i++) 110 load_hostkeys(hostkeys, hostname, options.user_hostfiles[i]); 111 for (i = 0; i < options.num_system_hostfiles; i++) 112 load_hostkeys(hostkeys, hostname, options.system_hostfiles[i]); 113 114 oavail = avail = xstrdup(KEX_DEFAULT_PK_ALG); 115 maxlen = strlen(avail) + 1; 116 first = xmalloc(maxlen); 117 last = xmalloc(maxlen); 118 *first = *last = '\0'; 119 120 #define ALG_APPEND(to, from) \ 121 do { \ 122 if (*to != '\0') \ 123 strlcat(to, ",", maxlen); \ 124 strlcat(to, from, maxlen); \ 125 } while (0) 126 127 while ((alg = strsep(&avail, ",")) && *alg != '\0') { 128 if ((ktype = sshkey_type_from_name(alg)) == KEY_UNSPEC) 129 fatal("%s: unknown alg %s", __func__, alg); 130 if (lookup_key_in_hostkeys_by_type(hostkeys, 131 sshkey_type_plain(ktype), NULL)) 132 ALG_APPEND(first, alg); 133 else 134 ALG_APPEND(last, alg); 135 } 136 #undef ALG_APPEND 137 xasprintf(&ret, "%s%s%s", first, 138 (*first == '\0' || *last == '\0') ? "" : ",", last); 139 if (*first != '\0') 140 debug3("%s: prefer hostkeyalgs: %s", __func__, first); 141 142 free(first); 143 free(last); 144 free(hostname); 145 free(oavail); 146 free_hostkeys(hostkeys); 147 148 return ret; 149 } 150 151 void 152 ssh_kex2(char *host, struct sockaddr *hostaddr, u_short port) 153 { 154 char *myproposal[PROPOSAL_MAX] = { KEX_CLIENT }; 155 char *s; 156 struct kex *kex; 157 int r; 158 159 xxx_host = host; 160 xxx_hostaddr = hostaddr; 161 162 if ((s = kex_names_cat(options.kex_algorithms, "ext-info-c")) == NULL) 163 fatal("%s: kex_names_cat", __func__); 164 myproposal[PROPOSAL_KEX_ALGS] = compat_kex_proposal(s); 165 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 166 compat_cipher_proposal(options.ciphers); 167 myproposal[PROPOSAL_ENC_ALGS_STOC] = 168 compat_cipher_proposal(options.ciphers); 169 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 170 myproposal[PROPOSAL_COMP_ALGS_STOC] = options.compression ? 171 "zlib@openssh.com,zlib,none" : "none,zlib@openssh.com,zlib"; 172 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 173 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 174 if (options.hostkeyalgorithms != NULL) { 175 if (kex_assemble_names(KEX_DEFAULT_PK_ALG, 176 &options.hostkeyalgorithms) != 0) 177 fatal("%s: kex_assemble_namelist", __func__); 178 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 179 compat_pkalg_proposal(options.hostkeyalgorithms); 180 } else { 181 /* Enforce default */ 182 options.hostkeyalgorithms = xstrdup(KEX_DEFAULT_PK_ALG); 183 /* Prefer algorithms that we already have keys for */ 184 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 185 compat_pkalg_proposal( 186 order_hostkeyalgs(host, hostaddr, port)); 187 } 188 189 if (options.rekey_limit || options.rekey_interval) 190 packet_set_rekey_limits(options.rekey_limit, 191 options.rekey_interval); 192 193 /* start key exchange */ 194 if ((r = kex_setup(active_state, myproposal)) != 0) 195 fatal("kex_setup: %s", ssh_err(r)); 196 kex = active_state->kex; 197 #ifdef WITH_OPENSSL 198 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 199 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 200 kex->kex[KEX_DH_GRP14_SHA256] = kexdh_client; 201 kex->kex[KEX_DH_GRP16_SHA512] = kexdh_client; 202 kex->kex[KEX_DH_GRP18_SHA512] = kexdh_client; 203 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 204 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 205 kex->kex[KEX_ECDH_SHA2] = kexecdh_client; 206 #endif 207 kex->kex[KEX_C25519_SHA256] = kexc25519_client; 208 kex->client_version_string=client_version_string; 209 kex->server_version_string=server_version_string; 210 kex->verify_host_key=&verify_host_key_callback; 211 212 ssh_dispatch_run_fatal(active_state, DISPATCH_BLOCK, &kex->done); 213 214 /* remove ext-info from the KEX proposals for rekeying */ 215 myproposal[PROPOSAL_KEX_ALGS] = 216 compat_kex_proposal(options.kex_algorithms); 217 if ((r = kex_prop2buf(kex->my, myproposal)) != 0) 218 fatal("kex_prop2buf: %s", ssh_err(r)); 219 220 session_id2 = kex->session_id; 221 session_id2_len = kex->session_id_len; 222 223 #ifdef DEBUG_KEXDH 224 /* send 1st encrypted/maced/compressed message */ 225 packet_start(SSH2_MSG_IGNORE); 226 packet_put_cstring("markus"); 227 packet_send(); 228 packet_write_wait(); 229 #endif 230 } 231 232 /* 233 * Authenticate user 234 */ 235 236 typedef struct cauthctxt Authctxt; 237 typedef struct cauthmethod Authmethod; 238 typedef struct identity Identity; 239 typedef struct idlist Idlist; 240 241 struct identity { 242 TAILQ_ENTRY(identity) next; 243 int agent_fd; /* >=0 if agent supports key */ 244 struct sshkey *key; /* public/private key */ 245 char *filename; /* comment for agent-only keys */ 246 int tried; 247 int isprivate; /* key points to the private key */ 248 int userprovided; 249 }; 250 TAILQ_HEAD(idlist, identity); 251 252 struct cauthctxt { 253 const char *server_user; 254 const char *local_user; 255 const char *host; 256 const char *service; 257 struct cauthmethod *method; 258 sig_atomic_t success; 259 char *authlist; 260 int attempt; 261 /* pubkey */ 262 struct idlist keys; 263 int agent_fd; 264 /* hostbased */ 265 Sensitive *sensitive; 266 char *oktypes, *ktypes; 267 const char *active_ktype; 268 /* kbd-interactive */ 269 int info_req_seen; 270 /* generic */ 271 void *methoddata; 272 }; 273 274 struct cauthmethod { 275 char *name; /* string to compare against server's list */ 276 int (*userauth)(Authctxt *authctxt); 277 void (*cleanup)(Authctxt *authctxt); 278 int *enabled; /* flag in option struct that enables method */ 279 int *batch_flag; /* flag in option struct that disables method */ 280 }; 281 282 int input_userauth_service_accept(int, u_int32_t, struct ssh *); 283 int input_userauth_ext_info(int, u_int32_t, struct ssh *); 284 int input_userauth_success(int, u_int32_t, struct ssh *); 285 int input_userauth_success_unexpected(int, u_int32_t, struct ssh *); 286 int input_userauth_failure(int, u_int32_t, struct ssh *); 287 int input_userauth_banner(int, u_int32_t, struct ssh *); 288 int input_userauth_error(int, u_int32_t, struct ssh *); 289 int input_userauth_info_req(int, u_int32_t, struct ssh *); 290 int input_userauth_pk_ok(int, u_int32_t, struct ssh *); 291 int input_userauth_passwd_changereq(int, u_int32_t, struct ssh *); 292 293 int userauth_none(Authctxt *); 294 int userauth_pubkey(Authctxt *); 295 int userauth_passwd(Authctxt *); 296 int userauth_kbdint(Authctxt *); 297 int userauth_hostbased(Authctxt *); 298 299 #ifdef GSSAPI 300 int userauth_gssapi(Authctxt *authctxt); 301 int input_gssapi_response(int type, u_int32_t, struct ssh *); 302 int input_gssapi_token(int type, u_int32_t, struct ssh *); 303 int input_gssapi_hash(int type, u_int32_t, struct ssh *); 304 int input_gssapi_error(int, u_int32_t, struct ssh *); 305 int input_gssapi_errtok(int, u_int32_t, struct ssh *); 306 #endif 307 308 void userauth(Authctxt *, char *); 309 310 static int sign_and_send_pubkey(Authctxt *, Identity *); 311 static void pubkey_prepare(Authctxt *); 312 static void pubkey_cleanup(Authctxt *); 313 static void pubkey_reset(Authctxt *); 314 static struct sshkey *load_identity_file(Identity *); 315 316 static Authmethod *authmethod_get(char *authlist); 317 static Authmethod *authmethod_lookup(const char *name); 318 static char *authmethods_get(void); 319 320 Authmethod authmethods[] = { 321 #ifdef GSSAPI 322 {"gssapi-with-mic", 323 userauth_gssapi, 324 NULL, 325 &options.gss_authentication, 326 NULL}, 327 #endif 328 {"hostbased", 329 userauth_hostbased, 330 NULL, 331 &options.hostbased_authentication, 332 NULL}, 333 {"publickey", 334 userauth_pubkey, 335 NULL, 336 &options.pubkey_authentication, 337 NULL}, 338 {"keyboard-interactive", 339 userauth_kbdint, 340 NULL, 341 &options.kbd_interactive_authentication, 342 &options.batch_mode}, 343 {"password", 344 userauth_passwd, 345 NULL, 346 &options.password_authentication, 347 &options.batch_mode}, 348 {"none", 349 userauth_none, 350 NULL, 351 NULL, 352 NULL}, 353 {NULL, NULL, NULL, NULL, NULL} 354 }; 355 356 void 357 ssh_userauth2(const char *local_user, const char *server_user, char *host, 358 Sensitive *sensitive) 359 { 360 struct ssh *ssh = active_state; 361 Authctxt authctxt; 362 int r; 363 364 if (options.challenge_response_authentication) 365 options.kbd_interactive_authentication = 1; 366 if (options.preferred_authentications == NULL) 367 options.preferred_authentications = authmethods_get(); 368 369 /* setup authentication context */ 370 memset(&authctxt, 0, sizeof(authctxt)); 371 pubkey_prepare(&authctxt); 372 authctxt.server_user = server_user; 373 authctxt.local_user = local_user; 374 authctxt.host = host; 375 authctxt.service = "ssh-connection"; /* service name */ 376 authctxt.success = 0; 377 authctxt.method = authmethod_lookup("none"); 378 authctxt.authlist = NULL; 379 authctxt.methoddata = NULL; 380 authctxt.sensitive = sensitive; 381 authctxt.active_ktype = authctxt.oktypes = authctxt.ktypes = NULL; 382 authctxt.info_req_seen = 0; 383 authctxt.agent_fd = -1; 384 if (authctxt.method == NULL) 385 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 386 387 if ((r = sshpkt_start(ssh, SSH2_MSG_SERVICE_REQUEST)) != 0 || 388 (r = sshpkt_put_cstring(ssh, "ssh-userauth")) != 0 || 389 (r = sshpkt_send(ssh)) != 0) 390 fatal("%s: %s", __func__, ssh_err(r)); 391 392 ssh->authctxt = &authctxt; 393 ssh_dispatch_init(ssh, &input_userauth_error); 394 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_ext_info); 395 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_ACCEPT, &input_userauth_service_accept); 396 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt.success); /* loop until success */ 397 ssh->authctxt = NULL; 398 399 pubkey_cleanup(&authctxt); 400 ssh_dispatch_range(ssh, SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 401 402 if (!authctxt.success) 403 fatal("Authentication failed."); 404 debug("Authentication succeeded (%s).", authctxt.method->name); 405 } 406 407 /* ARGSUSED */ 408 int 409 input_userauth_service_accept(int type, u_int32_t seq, struct ssh *ssh) 410 { 411 Authctxt *authctxt = ssh->authctxt; 412 int r; 413 414 if (ssh_packet_remaining(ssh) > 0) { 415 char *reply; 416 417 if ((r = sshpkt_get_cstring(ssh, &reply, NULL)) != 0) 418 goto out; 419 debug2("service_accept: %s", reply); 420 free(reply); 421 } else { 422 debug2("buggy server: service_accept w/o service"); 423 } 424 if ((r = sshpkt_get_end(ssh)) != 0) 425 goto out; 426 debug("SSH2_MSG_SERVICE_ACCEPT received"); 427 428 /* initial userauth request */ 429 userauth_none(authctxt); 430 431 ssh_dispatch_set(ssh, SSH2_MSG_EXT_INFO, &input_userauth_error); 432 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 433 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 434 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 435 r = 0; 436 out: 437 return r; 438 } 439 440 /* ARGSUSED */ 441 int 442 input_userauth_ext_info(int type, u_int32_t seqnr, struct ssh *ssh) 443 { 444 return kex_input_ext_info(type, seqnr, ssh); 445 } 446 447 void 448 userauth(Authctxt *authctxt, char *authlist) 449 { 450 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 451 authctxt->method->cleanup(authctxt); 452 453 free(authctxt->methoddata); 454 authctxt->methoddata = NULL; 455 if (authlist == NULL) { 456 authlist = authctxt->authlist; 457 } else { 458 free(authctxt->authlist); 459 authctxt->authlist = authlist; 460 } 461 for (;;) { 462 Authmethod *method = authmethod_get(authlist); 463 if (method == NULL) 464 fatal("%s@%s: Permission denied (%s).", 465 authctxt->server_user, authctxt->host, authlist); 466 authctxt->method = method; 467 468 /* reset the per method handler */ 469 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 470 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 471 472 /* and try new method */ 473 if (method->userauth(authctxt) != 0) { 474 debug2("we sent a %s packet, wait for reply", method->name); 475 break; 476 } else { 477 debug2("we did not send a packet, disable method"); 478 method->enabled = NULL; 479 } 480 } 481 } 482 483 /* ARGSUSED */ 484 int 485 input_userauth_error(int type, u_int32_t seq, struct ssh *ssh) 486 { 487 fatal("input_userauth_error: bad message during authentication: " 488 "type %d", type); 489 return 0; 490 } 491 492 /* ARGSUSED */ 493 int 494 input_userauth_banner(int type, u_int32_t seq, struct ssh *ssh) 495 { 496 char *msg, *lang; 497 u_int len; 498 499 debug3("%s", __func__); 500 msg = packet_get_string(&len); 501 lang = packet_get_string(NULL); 502 if (len > 0 && options.log_level >= SYSLOG_LEVEL_INFO) 503 fmprintf(stderr, "%s", msg); 504 free(msg); 505 free(lang); 506 return 0; 507 } 508 509 /* ARGSUSED */ 510 int 511 input_userauth_success(int type, u_int32_t seq, struct ssh *ssh) 512 { 513 Authctxt *authctxt = ssh->authctxt; 514 515 if (authctxt == NULL) 516 fatal("input_userauth_success: no authentication context"); 517 free(authctxt->authlist); 518 authctxt->authlist = NULL; 519 if (authctxt->method != NULL && authctxt->method->cleanup != NULL) 520 authctxt->method->cleanup(authctxt); 521 free(authctxt->methoddata); 522 authctxt->methoddata = NULL; 523 authctxt->success = 1; /* break out */ 524 return 0; 525 } 526 527 int 528 input_userauth_success_unexpected(int type, u_int32_t seq, struct ssh *ssh) 529 { 530 Authctxt *authctxt = ssh->authctxt; 531 532 if (authctxt == NULL) 533 fatal("%s: no authentication context", __func__); 534 535 fatal("Unexpected authentication success during %s.", 536 authctxt->method->name); 537 return 0; 538 } 539 540 /* ARGSUSED */ 541 int 542 input_userauth_failure(int type, u_int32_t seq, struct ssh *ssh) 543 { 544 Authctxt *authctxt = ssh->authctxt; 545 char *authlist = NULL; 546 int partial; 547 548 if (authctxt == NULL) 549 fatal("input_userauth_failure: no authentication context"); 550 551 authlist = packet_get_string(NULL); 552 partial = packet_get_char(); 553 packet_check_eom(); 554 555 if (partial != 0) { 556 verbose("Authenticated with partial success."); 557 /* reset state */ 558 pubkey_reset(authctxt); 559 } 560 debug("Authentications that can continue: %s", authlist); 561 562 userauth(authctxt, authlist); 563 return 0; 564 } 565 566 /* ARGSUSED */ 567 int 568 input_userauth_pk_ok(int type, u_int32_t seq, struct ssh *ssh) 569 { 570 Authctxt *authctxt = ssh->authctxt; 571 struct sshkey *key = NULL; 572 Identity *id = NULL; 573 Buffer b; 574 int pktype, sent = 0; 575 u_int alen, blen; 576 char *pkalg, *fp; 577 u_char *pkblob; 578 579 if (authctxt == NULL) 580 fatal("input_userauth_pk_ok: no authentication context"); 581 if (datafellows & SSH_BUG_PKOK) { 582 /* this is similar to SSH_BUG_PKAUTH */ 583 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 584 pkblob = packet_get_string(&blen); 585 buffer_init(&b); 586 buffer_append(&b, pkblob, blen); 587 pkalg = buffer_get_string(&b, &alen); 588 buffer_free(&b); 589 } else { 590 pkalg = packet_get_string(&alen); 591 pkblob = packet_get_string(&blen); 592 } 593 packet_check_eom(); 594 595 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 596 597 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 598 debug("unknown pkalg %s", pkalg); 599 goto done; 600 } 601 if ((key = key_from_blob(pkblob, blen)) == NULL) { 602 debug("no key from blob. pkalg %s", pkalg); 603 goto done; 604 } 605 if (key->type != pktype) { 606 error("input_userauth_pk_ok: type mismatch " 607 "for decoded key (received %d, expected %d)", 608 key->type, pktype); 609 goto done; 610 } 611 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 612 SSH_FP_DEFAULT)) == NULL) 613 goto done; 614 debug2("input_userauth_pk_ok: fp %s", fp); 615 free(fp); 616 617 /* 618 * search keys in the reverse order, because last candidate has been 619 * moved to the end of the queue. this also avoids confusion by 620 * duplicate keys 621 */ 622 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 623 if (key_equal(key, id->key)) { 624 sent = sign_and_send_pubkey(authctxt, id); 625 break; 626 } 627 } 628 done: 629 if (key != NULL) 630 key_free(key); 631 free(pkalg); 632 free(pkblob); 633 634 /* try another method if we did not send a packet */ 635 if (sent == 0) 636 userauth(authctxt, NULL); 637 return 0; 638 } 639 640 #ifdef GSSAPI 641 int 642 userauth_gssapi(Authctxt *authctxt) 643 { 644 Gssctxt *gssctxt = NULL; 645 static gss_OID_set gss_supported = NULL; 646 static u_int mech = 0; 647 OM_uint32 min; 648 int ok = 0; 649 650 /* Try one GSSAPI method at a time, rather than sending them all at 651 * once. */ 652 653 if (gss_supported == NULL) 654 gss_indicate_mechs(&min, &gss_supported); 655 656 /* Check to see if the mechanism is usable before we offer it */ 657 while (mech < gss_supported->count && !ok) { 658 /* My DER encoding requires length<128 */ 659 if (gss_supported->elements[mech].length < 128 && 660 ssh_gssapi_check_mechanism(&gssctxt, 661 &gss_supported->elements[mech], authctxt->host)) { 662 ok = 1; /* Mechanism works */ 663 } else { 664 mech++; 665 } 666 } 667 668 if (!ok) 669 return 0; 670 671 authctxt->methoddata=(void *)gssctxt; 672 673 packet_start(SSH2_MSG_USERAUTH_REQUEST); 674 packet_put_cstring(authctxt->server_user); 675 packet_put_cstring(authctxt->service); 676 packet_put_cstring(authctxt->method->name); 677 678 packet_put_int(1); 679 680 packet_put_int((gss_supported->elements[mech].length) + 2); 681 packet_put_char(SSH_GSS_OIDTYPE); 682 packet_put_char(gss_supported->elements[mech].length); 683 packet_put_raw(gss_supported->elements[mech].elements, 684 gss_supported->elements[mech].length); 685 686 packet_send(); 687 688 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 689 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 690 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 691 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 692 693 mech++; /* Move along to next candidate */ 694 695 return 1; 696 } 697 698 static OM_uint32 699 process_gssapi_token(struct ssh *ssh, gss_buffer_t recv_tok) 700 { 701 Authctxt *authctxt = ssh->authctxt; 702 Gssctxt *gssctxt = authctxt->methoddata; 703 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 704 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 705 gss_buffer_desc gssbuf; 706 OM_uint32 status, ms, flags; 707 Buffer b; 708 709 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 710 recv_tok, &send_tok, &flags); 711 712 if (send_tok.length > 0) { 713 if (GSS_ERROR(status)) 714 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 715 else 716 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 717 718 packet_put_string(send_tok.value, send_tok.length); 719 packet_send(); 720 gss_release_buffer(&ms, &send_tok); 721 } 722 723 if (status == GSS_S_COMPLETE) { 724 /* send either complete or MIC, depending on mechanism */ 725 if (!(flags & GSS_C_INTEG_FLAG)) { 726 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 727 packet_send(); 728 } else { 729 ssh_gssapi_buildmic(&b, authctxt->server_user, 730 authctxt->service, "gssapi-with-mic"); 731 732 gssbuf.value = buffer_ptr(&b); 733 gssbuf.length = buffer_len(&b); 734 735 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 736 737 if (!GSS_ERROR(status)) { 738 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 739 packet_put_string(mic.value, mic.length); 740 741 packet_send(); 742 } 743 744 buffer_free(&b); 745 gss_release_buffer(&ms, &mic); 746 } 747 } 748 749 return status; 750 } 751 752 /* ARGSUSED */ 753 int 754 input_gssapi_response(int type, u_int32_t plen, struct ssh *ssh) 755 { 756 Authctxt *authctxt = ssh->authctxt; 757 Gssctxt *gssctxt; 758 int oidlen; 759 char *oidv; 760 761 if (authctxt == NULL) 762 fatal("input_gssapi_response: no authentication context"); 763 gssctxt = authctxt->methoddata; 764 765 /* Setup our OID */ 766 oidv = packet_get_string(&oidlen); 767 768 if (oidlen <= 2 || 769 oidv[0] != SSH_GSS_OIDTYPE || 770 oidv[1] != oidlen - 2) { 771 free(oidv); 772 debug("Badly encoded mechanism OID received"); 773 userauth(authctxt, NULL); 774 return 0; 775 } 776 777 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 778 fatal("Server returned different OID than expected"); 779 780 packet_check_eom(); 781 782 free(oidv); 783 784 if (GSS_ERROR(process_gssapi_token(ssh, GSS_C_NO_BUFFER))) { 785 /* Start again with next method on list */ 786 debug("Trying to start again"); 787 userauth(authctxt, NULL); 788 return 0; 789 } 790 return 0; 791 } 792 793 /* ARGSUSED */ 794 int 795 input_gssapi_token(int type, u_int32_t plen, struct ssh *ssh) 796 { 797 Authctxt *authctxt = ssh->authctxt; 798 gss_buffer_desc recv_tok; 799 OM_uint32 status; 800 u_int slen; 801 802 if (authctxt == NULL) 803 fatal("input_gssapi_response: no authentication context"); 804 805 recv_tok.value = packet_get_string(&slen); 806 recv_tok.length = slen; /* safe typecast */ 807 808 packet_check_eom(); 809 810 status = process_gssapi_token(ssh, &recv_tok); 811 812 free(recv_tok.value); 813 814 if (GSS_ERROR(status)) { 815 /* Start again with the next method in the list */ 816 userauth(authctxt, NULL); 817 return 0; 818 } 819 return 0; 820 } 821 822 /* ARGSUSED */ 823 int 824 input_gssapi_errtok(int type, u_int32_t plen, struct ssh *ssh) 825 { 826 Authctxt *authctxt = ssh->authctxt; 827 Gssctxt *gssctxt; 828 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 829 gss_buffer_desc recv_tok; 830 OM_uint32 ms; 831 u_int len; 832 833 if (authctxt == NULL) 834 fatal("input_gssapi_response: no authentication context"); 835 gssctxt = authctxt->methoddata; 836 837 recv_tok.value = packet_get_string(&len); 838 recv_tok.length = len; 839 840 packet_check_eom(); 841 842 /* Stick it into GSSAPI and see what it says */ 843 (void)ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 844 &recv_tok, &send_tok, NULL); 845 846 free(recv_tok.value); 847 gss_release_buffer(&ms, &send_tok); 848 849 /* Server will be returning a failed packet after this one */ 850 return 0; 851 } 852 853 /* ARGSUSED */ 854 int 855 input_gssapi_error(int type, u_int32_t plen, struct ssh *ssh) 856 { 857 char *msg; 858 char *lang; 859 860 /* maj */(void)packet_get_int(); 861 /* min */(void)packet_get_int(); 862 msg=packet_get_string(NULL); 863 lang=packet_get_string(NULL); 864 865 packet_check_eom(); 866 867 debug("Server GSSAPI Error:\n%s", msg); 868 free(msg); 869 free(lang); 870 return 0; 871 } 872 #endif /* GSSAPI */ 873 874 int 875 userauth_none(Authctxt *authctxt) 876 { 877 /* initial userauth request */ 878 packet_start(SSH2_MSG_USERAUTH_REQUEST); 879 packet_put_cstring(authctxt->server_user); 880 packet_put_cstring(authctxt->service); 881 packet_put_cstring(authctxt->method->name); 882 packet_send(); 883 return 1; 884 } 885 886 int 887 userauth_passwd(Authctxt *authctxt) 888 { 889 static int attempt = 0; 890 char prompt[150]; 891 char *password; 892 const char *host = options.host_key_alias ? options.host_key_alias : 893 authctxt->host; 894 895 if (attempt++ >= options.number_of_password_prompts) 896 return 0; 897 898 if (attempt != 1) 899 error("Permission denied, please try again."); 900 901 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 902 authctxt->server_user, host); 903 password = read_passphrase(prompt, 0); 904 packet_start(SSH2_MSG_USERAUTH_REQUEST); 905 packet_put_cstring(authctxt->server_user); 906 packet_put_cstring(authctxt->service); 907 packet_put_cstring(authctxt->method->name); 908 packet_put_char(0); 909 packet_put_cstring(password); 910 explicit_bzero(password, strlen(password)); 911 free(password); 912 packet_add_padding(64); 913 packet_send(); 914 915 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 916 &input_userauth_passwd_changereq); 917 918 return 1; 919 } 920 921 /* 922 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 923 */ 924 /* ARGSUSED */ 925 int 926 input_userauth_passwd_changereq(int type, u_int32_t seqnr, struct ssh *ssh) 927 { 928 Authctxt *authctxt = ssh->authctxt; 929 char *info, *lang, *password = NULL, *retype = NULL; 930 char prompt[150]; 931 const char *host; 932 933 debug2("input_userauth_passwd_changereq"); 934 935 if (authctxt == NULL) 936 fatal("input_userauth_passwd_changereq: " 937 "no authentication context"); 938 host = options.host_key_alias ? options.host_key_alias : authctxt->host; 939 940 info = packet_get_string(NULL); 941 lang = packet_get_string(NULL); 942 if (strlen(info) > 0) 943 logit("%s", info); 944 free(info); 945 free(lang); 946 packet_start(SSH2_MSG_USERAUTH_REQUEST); 947 packet_put_cstring(authctxt->server_user); 948 packet_put_cstring(authctxt->service); 949 packet_put_cstring(authctxt->method->name); 950 packet_put_char(1); /* additional info */ 951 snprintf(prompt, sizeof(prompt), 952 "Enter %.30s@%.128s's old password: ", 953 authctxt->server_user, host); 954 password = read_passphrase(prompt, 0); 955 packet_put_cstring(password); 956 explicit_bzero(password, strlen(password)); 957 free(password); 958 password = NULL; 959 while (password == NULL) { 960 snprintf(prompt, sizeof(prompt), 961 "Enter %.30s@%.128s's new password: ", 962 authctxt->server_user, host); 963 password = read_passphrase(prompt, RP_ALLOW_EOF); 964 if (password == NULL) { 965 /* bail out */ 966 return 0; 967 } 968 snprintf(prompt, sizeof(prompt), 969 "Retype %.30s@%.128s's new password: ", 970 authctxt->server_user, host); 971 retype = read_passphrase(prompt, 0); 972 if (strcmp(password, retype) != 0) { 973 explicit_bzero(password, strlen(password)); 974 free(password); 975 logit("Mismatch; try again, EOF to quit."); 976 password = NULL; 977 } 978 explicit_bzero(retype, strlen(retype)); 979 free(retype); 980 } 981 packet_put_cstring(password); 982 explicit_bzero(password, strlen(password)); 983 free(password); 984 packet_add_padding(64); 985 packet_send(); 986 987 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 988 &input_userauth_passwd_changereq); 989 return 0; 990 } 991 992 static const char * 993 key_sign_encode(const struct sshkey *key) 994 { 995 struct ssh *ssh = active_state; 996 997 if (key->type == KEY_RSA) { 998 switch (ssh->kex->rsa_sha2) { 999 case 256: 1000 return "rsa-sha2-256"; 1001 case 512: 1002 return "rsa-sha2-512"; 1003 } 1004 } 1005 return key_ssh_name(key); 1006 } 1007 1008 static int 1009 identity_sign(struct identity *id, u_char **sigp, size_t *lenp, 1010 const u_char *data, size_t datalen, u_int compat) 1011 { 1012 struct sshkey *prv; 1013 int ret; 1014 1015 /* the agent supports this key */ 1016 if (id->key != NULL && id->agent_fd != -1) 1017 return ssh_agent_sign(id->agent_fd, id->key, sigp, lenp, 1018 data, datalen, key_sign_encode(id->key), compat); 1019 1020 /* 1021 * we have already loaded the private key or 1022 * the private key is stored in external hardware 1023 */ 1024 if (id->key != NULL && 1025 (id->isprivate || (id->key->flags & SSHKEY_FLAG_EXT))) 1026 return (sshkey_sign(id->key, sigp, lenp, data, datalen, 1027 key_sign_encode(id->key), compat)); 1028 1029 /* load the private key from the file */ 1030 if ((prv = load_identity_file(id)) == NULL) 1031 return SSH_ERR_KEY_NOT_FOUND; 1032 ret = sshkey_sign(prv, sigp, lenp, data, datalen, 1033 key_sign_encode(prv), compat); 1034 sshkey_free(prv); 1035 return (ret); 1036 } 1037 1038 static int 1039 id_filename_matches(Identity *id, Identity *private_id) 1040 { 1041 const char *suffixes[] = { ".pub", "-cert.pub", NULL }; 1042 size_t len = strlen(id->filename), plen = strlen(private_id->filename); 1043 size_t i, slen; 1044 1045 if (strcmp(id->filename, private_id->filename) == 0) 1046 return 1; 1047 for (i = 0; suffixes[i]; i++) { 1048 slen = strlen(suffixes[i]); 1049 if (len > slen && plen == len - slen && 1050 strcmp(id->filename + (len - slen), suffixes[i]) == 0 && 1051 memcmp(id->filename, private_id->filename, plen) == 0) 1052 return 1; 1053 } 1054 return 0; 1055 } 1056 1057 static int 1058 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 1059 { 1060 Buffer b; 1061 Identity *private_id; 1062 u_char *blob, *signature; 1063 size_t slen; 1064 u_int bloblen, skip = 0; 1065 int matched, ret = -1, have_sig = 1; 1066 char *fp; 1067 1068 if ((fp = sshkey_fingerprint(id->key, options.fingerprint_hash, 1069 SSH_FP_DEFAULT)) == NULL) 1070 return 0; 1071 debug3("%s: %s %s", __func__, key_type(id->key), fp); 1072 free(fp); 1073 1074 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1075 /* we cannot handle this key */ 1076 debug3("sign_and_send_pubkey: cannot handle key"); 1077 return 0; 1078 } 1079 /* data to be signed */ 1080 buffer_init(&b); 1081 if (datafellows & SSH_OLD_SESSIONID) { 1082 buffer_append(&b, session_id2, session_id2_len); 1083 skip = session_id2_len; 1084 } else { 1085 buffer_put_string(&b, session_id2, session_id2_len); 1086 skip = buffer_len(&b); 1087 } 1088 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1089 buffer_put_cstring(&b, authctxt->server_user); 1090 buffer_put_cstring(&b, 1091 datafellows & SSH_BUG_PKSERVICE ? 1092 "ssh-userauth" : 1093 authctxt->service); 1094 if (datafellows & SSH_BUG_PKAUTH) { 1095 buffer_put_char(&b, have_sig); 1096 } else { 1097 buffer_put_cstring(&b, authctxt->method->name); 1098 buffer_put_char(&b, have_sig); 1099 buffer_put_cstring(&b, key_sign_encode(id->key)); 1100 } 1101 buffer_put_string(&b, blob, bloblen); 1102 1103 /* 1104 * If the key is an certificate, try to find a matching private key 1105 * and use it to complete the signature. 1106 * If no such private key exists, fall back to trying the certificate 1107 * key itself in case it has a private half already loaded. 1108 */ 1109 if (key_is_cert(id->key)) { 1110 matched = 0; 1111 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1112 if (sshkey_equal_public(id->key, private_id->key) && 1113 id->key->type != private_id->key->type) { 1114 id = private_id; 1115 matched = 1; 1116 break; 1117 } 1118 } 1119 /* 1120 * Exact key matches are preferred, but also allow 1121 * filename matches for non-PKCS#11/agent keys that 1122 * didn't load public keys. This supports the case 1123 * of keeping just a private key file and public 1124 * certificate on disk. 1125 */ 1126 if (!matched && !id->isprivate && id->agent_fd == -1 && 1127 (id->key->flags & SSHKEY_FLAG_EXT) == 0) { 1128 TAILQ_FOREACH(private_id, &authctxt->keys, next) { 1129 if (private_id->key == NULL && 1130 id_filename_matches(id, private_id)) { 1131 id = private_id; 1132 matched = 1; 1133 break; 1134 } 1135 } 1136 } 1137 if (matched) { 1138 debug2("%s: using private key \"%s\"%s for " 1139 "certificate", __func__, id->filename, 1140 id->agent_fd != -1 ? " from agent" : ""); 1141 } else { 1142 debug("%s: no separate private key for certificate " 1143 "\"%s\"", __func__, id->filename); 1144 } 1145 } 1146 1147 /* generate signature */ 1148 ret = identity_sign(id, &signature, &slen, 1149 buffer_ptr(&b), buffer_len(&b), datafellows); 1150 if (ret != 0) { 1151 if (ret != SSH_ERR_KEY_NOT_FOUND) 1152 error("%s: signing failed: %s", __func__, ssh_err(ret)); 1153 free(blob); 1154 buffer_free(&b); 1155 return 0; 1156 } 1157 #ifdef DEBUG_PK 1158 buffer_dump(&b); 1159 #endif 1160 if (datafellows & SSH_BUG_PKSERVICE) { 1161 buffer_clear(&b); 1162 buffer_append(&b, session_id2, session_id2_len); 1163 skip = session_id2_len; 1164 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1165 buffer_put_cstring(&b, authctxt->server_user); 1166 buffer_put_cstring(&b, authctxt->service); 1167 buffer_put_cstring(&b, authctxt->method->name); 1168 buffer_put_char(&b, have_sig); 1169 if (!(datafellows & SSH_BUG_PKAUTH)) 1170 buffer_put_cstring(&b, key_ssh_name(id->key)); 1171 buffer_put_string(&b, blob, bloblen); 1172 } 1173 free(blob); 1174 1175 /* append signature */ 1176 buffer_put_string(&b, signature, slen); 1177 free(signature); 1178 1179 /* skip session id and packet type */ 1180 if (buffer_len(&b) < skip + 1) 1181 fatal("userauth_pubkey: internal error"); 1182 buffer_consume(&b, skip + 1); 1183 1184 /* put remaining data from buffer into packet */ 1185 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1186 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 1187 buffer_free(&b); 1188 packet_send(); 1189 1190 return 1; 1191 } 1192 1193 static int 1194 send_pubkey_test(Authctxt *authctxt, Identity *id) 1195 { 1196 u_char *blob; 1197 u_int bloblen, have_sig = 0; 1198 1199 debug3("send_pubkey_test"); 1200 1201 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 1202 /* we cannot handle this key */ 1203 debug3("send_pubkey_test: cannot handle key"); 1204 return 0; 1205 } 1206 /* register callback for USERAUTH_PK_OK message */ 1207 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 1208 1209 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1210 packet_put_cstring(authctxt->server_user); 1211 packet_put_cstring(authctxt->service); 1212 packet_put_cstring(authctxt->method->name); 1213 packet_put_char(have_sig); 1214 if (!(datafellows & SSH_BUG_PKAUTH)) 1215 packet_put_cstring(key_sign_encode(id->key)); 1216 packet_put_string(blob, bloblen); 1217 free(blob); 1218 packet_send(); 1219 return 1; 1220 } 1221 1222 static struct sshkey * 1223 load_identity_file(Identity *id) 1224 { 1225 struct sshkey *private = NULL; 1226 char prompt[300], *passphrase, *comment; 1227 int r, perm_ok = 0, quit = 0, i; 1228 struct stat st; 1229 1230 if (stat(id->filename, &st) < 0) { 1231 (id->userprovided ? logit : debug3)("no such identity: %s: %s", 1232 id->filename, strerror(errno)); 1233 return NULL; 1234 } 1235 snprintf(prompt, sizeof prompt, 1236 "Enter passphrase for key '%.100s': ", id->filename); 1237 for (i = 0; i <= options.number_of_password_prompts; i++) { 1238 if (i == 0) 1239 passphrase = ""; 1240 else { 1241 passphrase = read_passphrase(prompt, 0); 1242 if (*passphrase == '\0') { 1243 debug2("no passphrase given, try next key"); 1244 free(passphrase); 1245 break; 1246 } 1247 } 1248 switch ((r = sshkey_load_private_type(KEY_UNSPEC, id->filename, 1249 passphrase, &private, &comment, &perm_ok))) { 1250 case 0: 1251 break; 1252 case SSH_ERR_KEY_WRONG_PASSPHRASE: 1253 if (options.batch_mode) { 1254 quit = 1; 1255 break; 1256 } 1257 if (i != 0) 1258 debug2("bad passphrase given, try again..."); 1259 break; 1260 case SSH_ERR_SYSTEM_ERROR: 1261 if (errno == ENOENT) { 1262 debug2("Load key \"%s\": %s", 1263 id->filename, ssh_err(r)); 1264 quit = 1; 1265 break; 1266 } 1267 /* FALLTHROUGH */ 1268 default: 1269 error("Load key \"%s\": %s", id->filename, ssh_err(r)); 1270 quit = 1; 1271 break; 1272 } 1273 if (!quit && private != NULL && id->agent_fd == -1 && 1274 !(id->key && id->isprivate)) 1275 maybe_add_key_to_agent(id->filename, private, comment, 1276 passphrase); 1277 if (i > 0) { 1278 explicit_bzero(passphrase, strlen(passphrase)); 1279 free(passphrase); 1280 } 1281 free(comment); 1282 if (private != NULL || quit) 1283 break; 1284 } 1285 return private; 1286 } 1287 1288 /* 1289 * try keys in the following order: 1290 * 1. certificates listed in the config file 1291 * 2. other input certificates 1292 * 3. agent keys that are found in the config file 1293 * 4. other agent keys 1294 * 5. keys that are only listed in the config file 1295 */ 1296 static void 1297 pubkey_prepare(Authctxt *authctxt) 1298 { 1299 struct identity *id, *id2, *tmp; 1300 struct idlist agent, files, *preferred; 1301 struct sshkey *key; 1302 int agent_fd = -1, i, r, found; 1303 size_t j; 1304 struct ssh_identitylist *idlist; 1305 1306 TAILQ_INIT(&agent); /* keys from the agent */ 1307 TAILQ_INIT(&files); /* keys from the config file */ 1308 preferred = &authctxt->keys; 1309 TAILQ_INIT(preferred); /* preferred order of keys */ 1310 1311 /* list of keys stored in the filesystem and PKCS#11 */ 1312 for (i = 0; i < options.num_identity_files; i++) { 1313 key = options.identity_keys[i]; 1314 if (key && key->cert && key->cert->type != SSH2_CERT_TYPE_USER) 1315 continue; 1316 options.identity_keys[i] = NULL; 1317 id = xcalloc(1, sizeof(*id)); 1318 id->agent_fd = -1; 1319 id->key = key; 1320 id->filename = xstrdup(options.identity_files[i]); 1321 id->userprovided = options.identity_file_userprovided[i]; 1322 TAILQ_INSERT_TAIL(&files, id, next); 1323 } 1324 /* list of certificates specified by user */ 1325 for (i = 0; i < options.num_certificate_files; i++) { 1326 key = options.certificates[i]; 1327 if (!key_is_cert(key) || key->cert == NULL || 1328 key->cert->type != SSH2_CERT_TYPE_USER) 1329 continue; 1330 id = xcalloc(1, sizeof(*id)); 1331 id->agent_fd = -1; 1332 id->key = key; 1333 id->filename = xstrdup(options.certificate_files[i]); 1334 id->userprovided = options.certificate_file_userprovided[i]; 1335 TAILQ_INSERT_TAIL(preferred, id, next); 1336 } 1337 /* list of keys supported by the agent */ 1338 if ((r = ssh_get_authentication_socket(&agent_fd)) != 0) { 1339 if (r != SSH_ERR_AGENT_NOT_PRESENT) 1340 debug("%s: ssh_get_authentication_socket: %s", 1341 __func__, ssh_err(r)); 1342 } else if ((r = ssh_fetch_identitylist(agent_fd, &idlist)) != 0) { 1343 if (r != SSH_ERR_AGENT_NO_IDENTITIES) 1344 debug("%s: ssh_fetch_identitylist: %s", 1345 __func__, ssh_err(r)); 1346 close(agent_fd); 1347 } else { 1348 for (j = 0; j < idlist->nkeys; j++) { 1349 found = 0; 1350 TAILQ_FOREACH(id, &files, next) { 1351 /* 1352 * agent keys from the config file are 1353 * preferred 1354 */ 1355 if (sshkey_equal(idlist->keys[j], id->key)) { 1356 TAILQ_REMOVE(&files, id, next); 1357 TAILQ_INSERT_TAIL(preferred, id, next); 1358 id->agent_fd = agent_fd; 1359 found = 1; 1360 break; 1361 } 1362 } 1363 if (!found && !options.identities_only) { 1364 id = xcalloc(1, sizeof(*id)); 1365 /* XXX "steals" key/comment from idlist */ 1366 id->key = idlist->keys[j]; 1367 id->filename = idlist->comments[j]; 1368 idlist->keys[j] = NULL; 1369 idlist->comments[j] = NULL; 1370 id->agent_fd = agent_fd; 1371 TAILQ_INSERT_TAIL(&agent, id, next); 1372 } 1373 } 1374 ssh_free_identitylist(idlist); 1375 /* append remaining agent keys */ 1376 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1377 TAILQ_REMOVE(&agent, id, next); 1378 TAILQ_INSERT_TAIL(preferred, id, next); 1379 } 1380 authctxt->agent_fd = agent_fd; 1381 } 1382 /* Prefer PKCS11 keys that are explicitly listed */ 1383 TAILQ_FOREACH_SAFE(id, &files, next, tmp) { 1384 if (id->key == NULL || (id->key->flags & SSHKEY_FLAG_EXT) == 0) 1385 continue; 1386 found = 0; 1387 TAILQ_FOREACH(id2, &files, next) { 1388 if (id2->key == NULL || 1389 (id2->key->flags & SSHKEY_FLAG_EXT) == 0) 1390 continue; 1391 if (sshkey_equal(id->key, id2->key)) { 1392 TAILQ_REMOVE(&files, id, next); 1393 TAILQ_INSERT_TAIL(preferred, id, next); 1394 found = 1; 1395 break; 1396 } 1397 } 1398 /* If IdentitiesOnly set and key not found then don't use it */ 1399 if (!found && options.identities_only) { 1400 TAILQ_REMOVE(&files, id, next); 1401 explicit_bzero(id, sizeof(*id)); 1402 free(id); 1403 } 1404 } 1405 /* append remaining keys from the config file */ 1406 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1407 TAILQ_REMOVE(&files, id, next); 1408 TAILQ_INSERT_TAIL(preferred, id, next); 1409 } 1410 /* finally, filter by PubkeyAcceptedKeyTypes */ 1411 TAILQ_FOREACH_SAFE(id, preferred, next, id2) { 1412 if (id->key != NULL && 1413 match_pattern_list(sshkey_ssh_name(id->key), 1414 options.pubkey_key_types, 0) != 1) { 1415 debug("Skipping %s key %s - " 1416 "not in PubkeyAcceptedKeyTypes", 1417 sshkey_ssh_name(id->key), id->filename); 1418 TAILQ_REMOVE(preferred, id, next); 1419 sshkey_free(id->key); 1420 free(id->filename); 1421 memset(id, 0, sizeof(*id)); 1422 continue; 1423 } 1424 debug2("key: %s (%p)%s%s", id->filename, id->key, 1425 id->userprovided ? ", explicit" : "", 1426 id->agent_fd != -1 ? ", agent" : ""); 1427 } 1428 } 1429 1430 static void 1431 pubkey_cleanup(Authctxt *authctxt) 1432 { 1433 Identity *id; 1434 1435 if (authctxt->agent_fd != -1) 1436 ssh_close_authentication_socket(authctxt->agent_fd); 1437 for (id = TAILQ_FIRST(&authctxt->keys); id; 1438 id = TAILQ_FIRST(&authctxt->keys)) { 1439 TAILQ_REMOVE(&authctxt->keys, id, next); 1440 sshkey_free(id->key); 1441 free(id->filename); 1442 free(id); 1443 } 1444 } 1445 1446 static void 1447 pubkey_reset(Authctxt *authctxt) 1448 { 1449 Identity *id; 1450 1451 TAILQ_FOREACH(id, &authctxt->keys, next) 1452 id->tried = 0; 1453 } 1454 1455 static int 1456 try_identity(Identity *id) 1457 { 1458 if (!id->key) 1459 return (0); 1460 if (key_type_plain(id->key->type) == KEY_RSA && 1461 (datafellows & SSH_BUG_RSASIGMD5) != 0) { 1462 debug("Skipped %s key %s for RSA/MD5 server", 1463 key_type(id->key), id->filename); 1464 return (0); 1465 } 1466 return 1; 1467 } 1468 1469 int 1470 userauth_pubkey(Authctxt *authctxt) 1471 { 1472 Identity *id; 1473 int sent = 0; 1474 char *fp; 1475 1476 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1477 if (id->tried++) 1478 return (0); 1479 /* move key to the end of the queue */ 1480 TAILQ_REMOVE(&authctxt->keys, id, next); 1481 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1482 /* 1483 * send a test message if we have the public key. for 1484 * encrypted keys we cannot do this and have to load the 1485 * private key instead 1486 */ 1487 if (id->key != NULL) { 1488 if (try_identity(id)) { 1489 if ((fp = sshkey_fingerprint(id->key, 1490 options.fingerprint_hash, 1491 SSH_FP_DEFAULT)) == NULL) { 1492 error("%s: sshkey_fingerprint failed", 1493 __func__); 1494 return 0; 1495 } 1496 debug("Offering public key: %s %s %s", 1497 sshkey_type(id->key), fp, id->filename); 1498 free(fp); 1499 sent = send_pubkey_test(authctxt, id); 1500 } 1501 } else { 1502 debug("Trying private key: %s", id->filename); 1503 id->key = load_identity_file(id); 1504 if (id->key != NULL) { 1505 if (try_identity(id)) { 1506 id->isprivate = 1; 1507 sent = sign_and_send_pubkey( 1508 authctxt, id); 1509 } 1510 key_free(id->key); 1511 id->key = NULL; 1512 id->isprivate = 0; 1513 } 1514 } 1515 if (sent) 1516 return (sent); 1517 } 1518 return (0); 1519 } 1520 1521 /* 1522 * Send userauth request message specifying keyboard-interactive method. 1523 */ 1524 int 1525 userauth_kbdint(Authctxt *authctxt) 1526 { 1527 static int attempt = 0; 1528 1529 if (attempt++ >= options.number_of_password_prompts) 1530 return 0; 1531 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1532 if (attempt > 1 && !authctxt->info_req_seen) { 1533 debug3("userauth_kbdint: disable: no info_req_seen"); 1534 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1535 return 0; 1536 } 1537 1538 debug2("userauth_kbdint"); 1539 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1540 packet_put_cstring(authctxt->server_user); 1541 packet_put_cstring(authctxt->service); 1542 packet_put_cstring(authctxt->method->name); 1543 packet_put_cstring(""); /* lang */ 1544 packet_put_cstring(options.kbd_interactive_devices ? 1545 options.kbd_interactive_devices : ""); 1546 packet_send(); 1547 1548 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1549 return 1; 1550 } 1551 1552 /* 1553 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1554 */ 1555 int 1556 input_userauth_info_req(int type, u_int32_t seq, struct ssh *ssh) 1557 { 1558 Authctxt *authctxt = ssh->authctxt; 1559 char *name, *inst, *lang, *prompt, *response; 1560 u_int num_prompts, i; 1561 int echo = 0; 1562 1563 debug2("input_userauth_info_req"); 1564 1565 if (authctxt == NULL) 1566 fatal("input_userauth_info_req: no authentication context"); 1567 1568 authctxt->info_req_seen = 1; 1569 1570 name = packet_get_string(NULL); 1571 inst = packet_get_string(NULL); 1572 lang = packet_get_string(NULL); 1573 if (strlen(name) > 0) 1574 logit("%s", name); 1575 if (strlen(inst) > 0) 1576 logit("%s", inst); 1577 free(name); 1578 free(inst); 1579 free(lang); 1580 1581 num_prompts = packet_get_int(); 1582 /* 1583 * Begin to build info response packet based on prompts requested. 1584 * We commit to providing the correct number of responses, so if 1585 * further on we run into a problem that prevents this, we have to 1586 * be sure and clean this up and send a correct error response. 1587 */ 1588 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1589 packet_put_int(num_prompts); 1590 1591 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1592 for (i = 0; i < num_prompts; i++) { 1593 prompt = packet_get_string(NULL); 1594 echo = packet_get_char(); 1595 1596 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1597 1598 packet_put_cstring(response); 1599 explicit_bzero(response, strlen(response)); 1600 free(response); 1601 free(prompt); 1602 } 1603 packet_check_eom(); /* done with parsing incoming message. */ 1604 1605 packet_add_padding(64); 1606 packet_send(); 1607 return 0; 1608 } 1609 1610 static int 1611 ssh_keysign(struct sshkey *key, u_char **sigp, size_t *lenp, 1612 const u_char *data, size_t datalen) 1613 { 1614 struct sshbuf *b; 1615 struct stat st; 1616 pid_t pid; 1617 int i, r, to[2], from[2], status, sock = packet_get_connection_in(); 1618 u_char rversion = 0, version = 2; 1619 void (*osigchld)(int); 1620 1621 *sigp = NULL; 1622 *lenp = 0; 1623 1624 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1625 error("%s: not installed: %s", __func__, strerror(errno)); 1626 return -1; 1627 } 1628 if (fflush(stdout) != 0) { 1629 error("%s: fflush: %s", __func__, strerror(errno)); 1630 return -1; 1631 } 1632 if (pipe(to) < 0) { 1633 error("%s: pipe: %s", __func__, strerror(errno)); 1634 return -1; 1635 } 1636 if (pipe(from) < 0) { 1637 error("%s: pipe: %s", __func__, strerror(errno)); 1638 return -1; 1639 } 1640 if ((pid = fork()) < 0) { 1641 error("%s: fork: %s", __func__, strerror(errno)); 1642 return -1; 1643 } 1644 osigchld = signal(SIGCHLD, SIG_DFL); 1645 if (pid == 0) { 1646 /* keep the socket on exec */ 1647 fcntl(sock, F_SETFD, 0); 1648 permanently_drop_suid(getuid()); 1649 close(from[0]); 1650 if (dup2(from[1], STDOUT_FILENO) < 0) 1651 fatal("%s: dup2: %s", __func__, strerror(errno)); 1652 close(to[1]); 1653 if (dup2(to[0], STDIN_FILENO) < 0) 1654 fatal("%s: dup2: %s", __func__, strerror(errno)); 1655 close(from[1]); 1656 close(to[0]); 1657 /* Close everything but stdio and the socket */ 1658 for (i = STDERR_FILENO + 1; i < sock; i++) 1659 close(i); 1660 closefrom(sock + 1); 1661 debug3("%s: [child] pid=%ld, exec %s", 1662 __func__, (long)getpid(), _PATH_SSH_KEY_SIGN); 1663 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *)NULL); 1664 fatal("%s: exec(%s): %s", __func__, _PATH_SSH_KEY_SIGN, 1665 strerror(errno)); 1666 } 1667 close(from[1]); 1668 close(to[0]); 1669 1670 if ((b = sshbuf_new()) == NULL) 1671 fatal("%s: sshbuf_new failed", __func__); 1672 /* send # of sock, data to be signed */ 1673 if ((r = sshbuf_put_u32(b, sock)) != 0 || 1674 (r = sshbuf_put_string(b, data, datalen)) != 0) 1675 fatal("%s: buffer error: %s", __func__, ssh_err(r)); 1676 if (ssh_msg_send(to[1], version, b) == -1) 1677 fatal("%s: couldn't send request", __func__); 1678 sshbuf_reset(b); 1679 r = ssh_msg_recv(from[0], b); 1680 close(from[0]); 1681 close(to[1]); 1682 if (r < 0) { 1683 error("%s: no reply", __func__); 1684 goto fail; 1685 } 1686 1687 errno = 0; 1688 while (waitpid(pid, &status, 0) < 0) { 1689 if (errno != EINTR) { 1690 error("%s: waitpid %ld: %s", 1691 __func__, (long)pid, strerror(errno)); 1692 goto fail; 1693 } 1694 } 1695 if (!WIFEXITED(status)) { 1696 error("%s: exited abnormally", __func__); 1697 goto fail; 1698 } 1699 if (WEXITSTATUS(status) != 0) { 1700 error("%s: exited with status %d", 1701 __func__, WEXITSTATUS(status)); 1702 goto fail; 1703 } 1704 if ((r = sshbuf_get_u8(b, &rversion)) != 0) { 1705 error("%s: buffer error: %s", __func__, ssh_err(r)); 1706 goto fail; 1707 } 1708 if (rversion != version) { 1709 error("%s: bad version", __func__); 1710 goto fail; 1711 } 1712 if ((r = sshbuf_get_string(b, sigp, lenp)) != 0) { 1713 error("%s: buffer error: %s", __func__, ssh_err(r)); 1714 fail: 1715 signal(SIGCHLD, osigchld); 1716 sshbuf_free(b); 1717 return -1; 1718 } 1719 signal(SIGCHLD, osigchld); 1720 sshbuf_free(b); 1721 1722 return 0; 1723 } 1724 1725 int 1726 userauth_hostbased(Authctxt *authctxt) 1727 { 1728 struct ssh *ssh = active_state; 1729 struct sshkey *private = NULL; 1730 struct sshbuf *b = NULL; 1731 const char *service; 1732 u_char *sig = NULL, *keyblob = NULL; 1733 char *fp = NULL, *chost = NULL, *lname = NULL; 1734 size_t siglen = 0, keylen = 0; 1735 int i, r, success = 0; 1736 1737 if (authctxt->ktypes == NULL) { 1738 authctxt->oktypes = xstrdup(options.hostbased_key_types); 1739 authctxt->ktypes = authctxt->oktypes; 1740 } 1741 1742 /* 1743 * Work through each listed type pattern in HostbasedKeyTypes, 1744 * trying each hostkey that matches the type in turn. 1745 */ 1746 for (;;) { 1747 if (authctxt->active_ktype == NULL) 1748 authctxt->active_ktype = strsep(&authctxt->ktypes, ","); 1749 if (authctxt->active_ktype == NULL || 1750 *authctxt->active_ktype == '\0') 1751 break; 1752 debug3("%s: trying key type %s", __func__, 1753 authctxt->active_ktype); 1754 1755 /* check for a useful key */ 1756 private = NULL; 1757 for (i = 0; i < authctxt->sensitive->nkeys; i++) { 1758 if (authctxt->sensitive->keys[i] == NULL || 1759 authctxt->sensitive->keys[i]->type == KEY_UNSPEC) 1760 continue; 1761 if (match_pattern_list( 1762 sshkey_ssh_name(authctxt->sensitive->keys[i]), 1763 authctxt->active_ktype, 0) != 1) 1764 continue; 1765 /* we take and free the key */ 1766 private = authctxt->sensitive->keys[i]; 1767 authctxt->sensitive->keys[i] = NULL; 1768 break; 1769 } 1770 /* Found one */ 1771 if (private != NULL) 1772 break; 1773 /* No more keys of this type; advance */ 1774 authctxt->active_ktype = NULL; 1775 } 1776 if (private == NULL) { 1777 free(authctxt->oktypes); 1778 authctxt->oktypes = authctxt->ktypes = NULL; 1779 authctxt->active_ktype = NULL; 1780 debug("No more client hostkeys for hostbased authentication."); 1781 goto out; 1782 } 1783 1784 if ((fp = sshkey_fingerprint(private, options.fingerprint_hash, 1785 SSH_FP_DEFAULT)) == NULL) { 1786 error("%s: sshkey_fingerprint failed", __func__); 1787 goto out; 1788 } 1789 debug("%s: trying hostkey %s %s", 1790 __func__, sshkey_ssh_name(private), fp); 1791 1792 /* figure out a name for the client host */ 1793 if ((lname = get_local_name(packet_get_connection_in())) == NULL) { 1794 error("%s: cannot get local ipaddr/name", __func__); 1795 goto out; 1796 } 1797 1798 /* XXX sshbuf_put_stringf? */ 1799 xasprintf(&chost, "%s.", lname); 1800 debug2("%s: chost %s", __func__, chost); 1801 1802 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1803 authctxt->service; 1804 1805 /* construct data */ 1806 if ((b = sshbuf_new()) == NULL) { 1807 error("%s: sshbuf_new failed", __func__); 1808 goto out; 1809 } 1810 if ((r = sshkey_to_blob(private, &keyblob, &keylen)) != 0) { 1811 error("%s: sshkey_to_blob: %s", __func__, ssh_err(r)); 1812 goto out; 1813 } 1814 if ((r = sshbuf_put_string(b, session_id2, session_id2_len)) != 0 || 1815 (r = sshbuf_put_u8(b, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1816 (r = sshbuf_put_cstring(b, authctxt->server_user)) != 0 || 1817 (r = sshbuf_put_cstring(b, service)) != 0 || 1818 (r = sshbuf_put_cstring(b, authctxt->method->name)) != 0 || 1819 (r = sshbuf_put_cstring(b, key_ssh_name(private))) != 0 || 1820 (r = sshbuf_put_string(b, keyblob, keylen)) != 0 || 1821 (r = sshbuf_put_cstring(b, chost)) != 0 || 1822 (r = sshbuf_put_cstring(b, authctxt->local_user)) != 0) { 1823 error("%s: buffer error: %s", __func__, ssh_err(r)); 1824 goto out; 1825 } 1826 1827 #ifdef DEBUG_PK 1828 sshbuf_dump(b, stderr); 1829 #endif 1830 if (authctxt->sensitive->external_keysign) 1831 r = ssh_keysign(private, &sig, &siglen, 1832 sshbuf_ptr(b), sshbuf_len(b)); 1833 else if ((r = sshkey_sign(private, &sig, &siglen, 1834 sshbuf_ptr(b), sshbuf_len(b), NULL, datafellows)) != 0) 1835 debug("%s: sshkey_sign: %s", __func__, ssh_err(r)); 1836 if (r != 0) { 1837 error("sign using hostkey %s %s failed", 1838 sshkey_ssh_name(private), fp); 1839 goto out; 1840 } 1841 if ((r = sshpkt_start(ssh, SSH2_MSG_USERAUTH_REQUEST)) != 0 || 1842 (r = sshpkt_put_cstring(ssh, authctxt->server_user)) != 0 || 1843 (r = sshpkt_put_cstring(ssh, authctxt->service)) != 0 || 1844 (r = sshpkt_put_cstring(ssh, authctxt->method->name)) != 0 || 1845 (r = sshpkt_put_cstring(ssh, key_ssh_name(private))) != 0 || 1846 (r = sshpkt_put_string(ssh, keyblob, keylen)) != 0 || 1847 (r = sshpkt_put_cstring(ssh, chost)) != 0 || 1848 (r = sshpkt_put_cstring(ssh, authctxt->local_user)) != 0 || 1849 (r = sshpkt_put_string(ssh, sig, siglen)) != 0 || 1850 (r = sshpkt_send(ssh)) != 0) { 1851 error("%s: packet error: %s", __func__, ssh_err(r)); 1852 goto out; 1853 } 1854 success = 1; 1855 1856 out: 1857 if (sig != NULL) { 1858 explicit_bzero(sig, siglen); 1859 free(sig); 1860 } 1861 free(keyblob); 1862 free(lname); 1863 free(fp); 1864 free(chost); 1865 sshkey_free(private); 1866 sshbuf_free(b); 1867 1868 return success; 1869 } 1870 1871 /* find auth method */ 1872 1873 /* 1874 * given auth method name, if configurable options permit this method fill 1875 * in auth_ident field and return true, otherwise return false. 1876 */ 1877 static int 1878 authmethod_is_enabled(Authmethod *method) 1879 { 1880 if (method == NULL) 1881 return 0; 1882 /* return false if options indicate this method is disabled */ 1883 if (method->enabled == NULL || *method->enabled == 0) 1884 return 0; 1885 /* return false if batch mode is enabled but method needs interactive mode */ 1886 if (method->batch_flag != NULL && *method->batch_flag != 0) 1887 return 0; 1888 return 1; 1889 } 1890 1891 static Authmethod * 1892 authmethod_lookup(const char *name) 1893 { 1894 Authmethod *method = NULL; 1895 if (name != NULL) 1896 for (method = authmethods; method->name != NULL; method++) 1897 if (strcmp(name, method->name) == 0) 1898 return method; 1899 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1900 return NULL; 1901 } 1902 1903 /* XXX internal state */ 1904 static Authmethod *current = NULL; 1905 static char *supported = NULL; 1906 static char *preferred = NULL; 1907 1908 /* 1909 * Given the authentication method list sent by the server, return the 1910 * next method we should try. If the server initially sends a nil list, 1911 * use a built-in default list. 1912 */ 1913 static Authmethod * 1914 authmethod_get(char *authlist) 1915 { 1916 char *name = NULL; 1917 u_int next; 1918 1919 /* Use a suitable default if we're passed a nil list. */ 1920 if (authlist == NULL || strlen(authlist) == 0) 1921 authlist = options.preferred_authentications; 1922 1923 if (supported == NULL || strcmp(authlist, supported) != 0) { 1924 debug3("start over, passed a different list %s", authlist); 1925 free(supported); 1926 supported = xstrdup(authlist); 1927 preferred = options.preferred_authentications; 1928 debug3("preferred %s", preferred); 1929 current = NULL; 1930 } else if (current != NULL && authmethod_is_enabled(current)) 1931 return current; 1932 1933 for (;;) { 1934 if ((name = match_list(preferred, supported, &next)) == NULL) { 1935 debug("No more authentication methods to try."); 1936 current = NULL; 1937 return NULL; 1938 } 1939 preferred += next; 1940 debug3("authmethod_lookup %s", name); 1941 debug3("remaining preferred: %s", preferred); 1942 if ((current = authmethod_lookup(name)) != NULL && 1943 authmethod_is_enabled(current)) { 1944 debug3("authmethod_is_enabled %s", name); 1945 debug("Next authentication method: %s", name); 1946 free(name); 1947 return current; 1948 } 1949 free(name); 1950 } 1951 } 1952 1953 static char * 1954 authmethods_get(void) 1955 { 1956 Authmethod *method = NULL; 1957 Buffer b; 1958 char *list; 1959 1960 buffer_init(&b); 1961 for (method = authmethods; method->name != NULL; method++) { 1962 if (authmethod_is_enabled(method)) { 1963 if (buffer_len(&b) > 0) 1964 buffer_append(&b, ",", 1); 1965 buffer_append(&b, method->name, strlen(method->name)); 1966 } 1967 } 1968 if ((list = sshbuf_dup_string(&b)) == NULL) 1969 fatal("%s: sshbuf_dup_string failed", __func__); 1970 buffer_free(&b); 1971 return list; 1972 } 1973 1974