1 /* $OpenBSD: auth2.c,v 1.145 2018/03/03 03:15:51 djm Exp $ */ 2 /* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include "includes.h" 27 __RCSID("$FreeBSD$"); 28 29 #include <sys/types.h> 30 #include <sys/stat.h> 31 #include <sys/uio.h> 32 33 #include <fcntl.h> 34 #include <limits.h> 35 #include <pwd.h> 36 #include <stdarg.h> 37 #include <string.h> 38 #include <unistd.h> 39 40 #include "atomicio.h" 41 #include "xmalloc.h" 42 #include "ssh2.h" 43 #include "packet.h" 44 #include "log.h" 45 #include "buffer.h" 46 #include "misc.h" 47 #include "servconf.h" 48 #include "compat.h" 49 #include "key.h" 50 #include "hostfile.h" 51 #include "auth.h" 52 #include "dispatch.h" 53 #include "pathnames.h" 54 #include "buffer.h" 55 #include "blacklist_client.h" 56 57 #ifdef GSSAPI 58 #include "ssh-gss.h" 59 #endif 60 #include "monitor_wrap.h" 61 #include "ssherr.h" 62 63 /* import */ 64 extern ServerOptions options; 65 extern u_char *session_id2; 66 extern u_int session_id2_len; 67 extern Buffer loginmsg; 68 69 /* methods */ 70 71 extern Authmethod method_none; 72 extern Authmethod method_pubkey; 73 extern Authmethod method_passwd; 74 extern Authmethod method_kbdint; 75 extern Authmethod method_hostbased; 76 #ifdef GSSAPI 77 extern Authmethod method_gssapi; 78 #endif 79 80 Authmethod *authmethods[] = { 81 &method_none, 82 &method_pubkey, 83 #ifdef GSSAPI 84 &method_gssapi, 85 #endif 86 &method_passwd, 87 &method_kbdint, 88 &method_hostbased, 89 NULL 90 }; 91 92 /* protocol */ 93 94 static int input_service_request(int, u_int32_t, struct ssh *); 95 static int input_userauth_request(int, u_int32_t, struct ssh *); 96 97 /* helper */ 98 static Authmethod *authmethod_lookup(Authctxt *, const char *); 99 static char *authmethods_get(Authctxt *authctxt); 100 101 #define MATCH_NONE 0 /* method or submethod mismatch */ 102 #define MATCH_METHOD 1 /* method matches (no submethod specified) */ 103 #define MATCH_BOTH 2 /* method and submethod match */ 104 #define MATCH_PARTIAL 3 /* method matches, submethod can't be checked */ 105 static int list_starts_with(const char *, const char *, const char *); 106 107 char * 108 auth2_read_banner(void) 109 { 110 struct stat st; 111 char *banner = NULL; 112 size_t len, n; 113 int fd; 114 115 if ((fd = open(options.banner, O_RDONLY)) == -1) 116 return (NULL); 117 if (fstat(fd, &st) == -1) { 118 close(fd); 119 return (NULL); 120 } 121 if (st.st_size <= 0 || st.st_size > 1*1024*1024) { 122 close(fd); 123 return (NULL); 124 } 125 126 len = (size_t)st.st_size; /* truncate */ 127 banner = xmalloc(len + 1); 128 n = atomicio(read, fd, banner, len); 129 close(fd); 130 131 if (n != len) { 132 free(banner); 133 return (NULL); 134 } 135 banner[n] = '\0'; 136 137 return (banner); 138 } 139 140 void 141 userauth_send_banner(const char *msg) 142 { 143 packet_start(SSH2_MSG_USERAUTH_BANNER); 144 packet_put_cstring(msg); 145 packet_put_cstring(""); /* language, unused */ 146 packet_send(); 147 debug("%s: sent", __func__); 148 } 149 150 static void 151 userauth_banner(void) 152 { 153 char *banner = NULL; 154 155 if (options.banner == NULL) 156 return; 157 158 if ((banner = PRIVSEP(auth2_read_banner())) == NULL) 159 goto done; 160 userauth_send_banner(banner); 161 162 done: 163 free(banner); 164 } 165 166 /* 167 * loop until authctxt->success == TRUE 168 */ 169 void 170 do_authentication2(Authctxt *authctxt) 171 { 172 struct ssh *ssh = active_state; /* XXX */ 173 ssh->authctxt = authctxt; /* XXX move to caller */ 174 ssh_dispatch_init(ssh, &dispatch_protocol_error); 175 ssh_dispatch_set(ssh, SSH2_MSG_SERVICE_REQUEST, &input_service_request); 176 ssh_dispatch_run_fatal(ssh, DISPATCH_BLOCK, &authctxt->success); 177 ssh->authctxt = NULL; 178 } 179 180 /*ARGSUSED*/ 181 static int 182 input_service_request(int type, u_int32_t seq, struct ssh *ssh) 183 { 184 Authctxt *authctxt = ssh->authctxt; 185 u_int len; 186 int acceptit = 0; 187 char *service = packet_get_cstring(&len); 188 packet_check_eom(); 189 190 if (authctxt == NULL) 191 fatal("input_service_request: no authctxt"); 192 193 if (strcmp(service, "ssh-userauth") == 0) { 194 if (!authctxt->success) { 195 acceptit = 1; 196 /* now we can handle user-auth requests */ 197 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); 198 } 199 } 200 /* XXX all other service requests are denied */ 201 202 if (acceptit) { 203 packet_start(SSH2_MSG_SERVICE_ACCEPT); 204 packet_put_cstring(service); 205 packet_send(); 206 packet_write_wait(); 207 } else { 208 debug("bad service request %s", service); 209 packet_disconnect("bad service request %s", service); 210 } 211 free(service); 212 return 0; 213 } 214 215 /*ARGSUSED*/ 216 static int 217 input_userauth_request(int type, u_int32_t seq, struct ssh *ssh) 218 { 219 Authctxt *authctxt = ssh->authctxt; 220 Authmethod *m = NULL; 221 char *user, *service, *method, *style = NULL; 222 int authenticated = 0; 223 #ifdef HAVE_LOGIN_CAP 224 login_cap_t *lc; 225 const char *from_host, *from_ip; 226 #endif 227 228 if (authctxt == NULL) 229 fatal("input_userauth_request: no authctxt"); 230 231 user = packet_get_cstring(NULL); 232 service = packet_get_cstring(NULL); 233 method = packet_get_cstring(NULL); 234 debug("userauth-request for user %s service %s method %s", user, service, method); 235 debug("attempt %d failures %d", authctxt->attempt, authctxt->failures); 236 237 if ((style = strchr(user, ':')) != NULL) 238 *style++ = 0; 239 240 if (authctxt->attempt++ == 0) { 241 /* setup auth context */ 242 authctxt->pw = PRIVSEP(getpwnamallow(user)); 243 authctxt->user = xstrdup(user); 244 if (authctxt->pw && strcmp(service, "ssh-connection")==0) { 245 authctxt->valid = 1; 246 debug2("%s: setting up authctxt for %s", 247 __func__, user); 248 } else { 249 /* Invalid user, fake password information */ 250 authctxt->pw = fakepw(); 251 #ifdef SSH_AUDIT_EVENTS 252 PRIVSEP(audit_event(SSH_INVALID_USER)); 253 #endif 254 } 255 #ifdef USE_PAM 256 if (options.use_pam) 257 PRIVSEP(start_pam(authctxt)); 258 #endif 259 ssh_packet_set_log_preamble(ssh, "%suser %s", 260 authctxt->valid ? "authenticating " : "invalid ", user); 261 setproctitle("%s%s", authctxt->valid ? user : "unknown", 262 use_privsep ? " [net]" : ""); 263 authctxt->service = xstrdup(service); 264 authctxt->style = style ? xstrdup(style) : NULL; 265 if (use_privsep) 266 mm_inform_authserv(service, style); 267 userauth_banner(); 268 if (auth2_setup_methods_lists(authctxt) != 0) 269 packet_disconnect("no authentication methods enabled"); 270 } else if (strcmp(user, authctxt->user) != 0 || 271 strcmp(service, authctxt->service) != 0) { 272 packet_disconnect("Change of username or service not allowed: " 273 "(%s,%s) -> (%s,%s)", 274 authctxt->user, authctxt->service, user, service); 275 } 276 277 #ifdef HAVE_LOGIN_CAP 278 if (authctxt->pw != NULL && 279 (lc = login_getpwclass(authctxt->pw)) != NULL) { 280 logit("user %s login class %s", authctxt->pw->pw_name, 281 authctxt->pw->pw_class); 282 from_host = auth_get_canonical_hostname(ssh, options.use_dns); 283 from_ip = ssh_remote_ipaddr(ssh); 284 if (!auth_hostok(lc, from_host, from_ip)) { 285 logit("Denied connection for %.200s from %.200s [%.200s].", 286 authctxt->pw->pw_name, from_host, from_ip); 287 packet_disconnect("Sorry, you are not allowed to connect."); 288 } 289 if (!auth_timeok(lc, time(NULL))) { 290 logit("LOGIN %.200s REFUSED (TIME) FROM %.200s", 291 authctxt->pw->pw_name, from_host); 292 packet_disconnect("Logins not available right now."); 293 } 294 login_close(lc); 295 } 296 #endif /* HAVE_LOGIN_CAP */ 297 298 /* reset state */ 299 auth2_challenge_stop(ssh); 300 301 #ifdef GSSAPI 302 /* XXX move to auth2_gssapi_stop() */ 303 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL); 304 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL); 305 #endif 306 307 auth2_authctxt_reset_info(authctxt); 308 authctxt->postponed = 0; 309 authctxt->server_caused_failure = 0; 310 311 /* try to authenticate user */ 312 m = authmethod_lookup(authctxt, method); 313 if (m != NULL && authctxt->failures < options.max_authtries) { 314 debug2("input_userauth_request: try method %s", method); 315 authenticated = m->userauth(ssh); 316 } 317 userauth_finish(ssh, authenticated, method, NULL); 318 319 free(service); 320 free(user); 321 free(method); 322 return 0; 323 } 324 325 void 326 userauth_finish(struct ssh *ssh, int authenticated, const char *method, 327 const char *submethod) 328 { 329 Authctxt *authctxt = ssh->authctxt; 330 char *methods; 331 int partial = 0; 332 333 if (!authctxt->valid && authenticated) 334 fatal("INTERNAL ERROR: authenticated invalid user %s", 335 authctxt->user); 336 if (authenticated && authctxt->postponed) 337 fatal("INTERNAL ERROR: authenticated and postponed"); 338 339 /* Special handling for root */ 340 if (authenticated && authctxt->pw->pw_uid == 0 && 341 !auth_root_allowed(ssh, method)) { 342 authenticated = 0; 343 #ifdef SSH_AUDIT_EVENTS 344 PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED)); 345 #endif 346 } 347 348 if (authenticated && options.num_auth_methods != 0) { 349 if (!auth2_update_methods_lists(authctxt, method, submethod)) { 350 authenticated = 0; 351 partial = 1; 352 } 353 } 354 355 /* Log before sending the reply */ 356 auth_log(authctxt, authenticated, partial, method, submethod); 357 358 /* Update information exposed to session */ 359 if (authenticated || partial) 360 auth2_update_session_info(authctxt, method, submethod); 361 362 if (authctxt->postponed) 363 return; 364 365 #ifdef USE_PAM 366 if (options.use_pam && authenticated) { 367 if (!PRIVSEP(do_pam_account())) { 368 /* if PAM returned a message, send it to the user */ 369 if (buffer_len(&loginmsg) > 0) { 370 buffer_append(&loginmsg, "\0", 1); 371 userauth_send_banner(buffer_ptr(&loginmsg)); 372 packet_write_wait(); 373 } 374 fatal("Access denied for user %s by PAM account " 375 "configuration", authctxt->user); 376 } 377 } 378 #endif 379 380 if (authenticated == 1) { 381 /* turn off userauth */ 382 ssh_dispatch_set(ssh, SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore); 383 packet_start(SSH2_MSG_USERAUTH_SUCCESS); 384 packet_send(); 385 packet_write_wait(); 386 /* now we can break out */ 387 authctxt->success = 1; 388 ssh_packet_set_log_preamble(ssh, "user %s", authctxt->user); 389 } else { 390 /* Allow initial try of "none" auth without failure penalty */ 391 if (!partial && !authctxt->server_caused_failure && 392 (authctxt->attempt > 1 || strcmp(method, "none") != 0)) { 393 authctxt->failures++; 394 BLACKLIST_NOTIFY(BLACKLIST_AUTH_FAIL, "ssh"); 395 } 396 if (authctxt->failures >= options.max_authtries) { 397 #ifdef SSH_AUDIT_EVENTS 398 PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES)); 399 #endif 400 auth_maxtries_exceeded(authctxt); 401 } 402 methods = authmethods_get(authctxt); 403 debug3("%s: failure partial=%d next methods=\"%s\"", __func__, 404 partial, methods); 405 packet_start(SSH2_MSG_USERAUTH_FAILURE); 406 packet_put_cstring(methods); 407 packet_put_char(partial); 408 packet_send(); 409 packet_write_wait(); 410 free(methods); 411 } 412 } 413 414 /* 415 * Checks whether method is allowed by at least one AuthenticationMethods 416 * methods list. Returns 1 if allowed, or no methods lists configured. 417 * 0 otherwise. 418 */ 419 int 420 auth2_method_allowed(Authctxt *authctxt, const char *method, 421 const char *submethod) 422 { 423 u_int i; 424 425 /* 426 * NB. authctxt->num_auth_methods might be zero as a result of 427 * auth2_setup_methods_lists(), so check the configuration. 428 */ 429 if (options.num_auth_methods == 0) 430 return 1; 431 for (i = 0; i < authctxt->num_auth_methods; i++) { 432 if (list_starts_with(authctxt->auth_methods[i], method, 433 submethod) != MATCH_NONE) 434 return 1; 435 } 436 return 0; 437 } 438 439 static char * 440 authmethods_get(Authctxt *authctxt) 441 { 442 Buffer b; 443 char *list; 444 u_int i; 445 446 buffer_init(&b); 447 for (i = 0; authmethods[i] != NULL; i++) { 448 if (strcmp(authmethods[i]->name, "none") == 0) 449 continue; 450 if (authmethods[i]->enabled == NULL || 451 *(authmethods[i]->enabled) == 0) 452 continue; 453 if (!auth2_method_allowed(authctxt, authmethods[i]->name, 454 NULL)) 455 continue; 456 if (buffer_len(&b) > 0) 457 buffer_append(&b, ",", 1); 458 buffer_append(&b, authmethods[i]->name, 459 strlen(authmethods[i]->name)); 460 } 461 if ((list = sshbuf_dup_string(&b)) == NULL) 462 fatal("%s: sshbuf_dup_string failed", __func__); 463 buffer_free(&b); 464 return list; 465 } 466 467 static Authmethod * 468 authmethod_lookup(Authctxt *authctxt, const char *name) 469 { 470 int i; 471 472 if (name != NULL) 473 for (i = 0; authmethods[i] != NULL; i++) 474 if (authmethods[i]->enabled != NULL && 475 *(authmethods[i]->enabled) != 0 && 476 strcmp(name, authmethods[i]->name) == 0 && 477 auth2_method_allowed(authctxt, 478 authmethods[i]->name, NULL)) 479 return authmethods[i]; 480 debug2("Unrecognized authentication method name: %s", 481 name ? name : "NULL"); 482 return NULL; 483 } 484 485 /* 486 * Check a comma-separated list of methods for validity. Is need_enable is 487 * non-zero, then also require that the methods are enabled. 488 * Returns 0 on success or -1 if the methods list is invalid. 489 */ 490 int 491 auth2_methods_valid(const char *_methods, int need_enable) 492 { 493 char *methods, *omethods, *method, *p; 494 u_int i, found; 495 int ret = -1; 496 497 if (*_methods == '\0') { 498 error("empty authentication method list"); 499 return -1; 500 } 501 omethods = methods = xstrdup(_methods); 502 while ((method = strsep(&methods, ",")) != NULL) { 503 for (found = i = 0; !found && authmethods[i] != NULL; i++) { 504 if ((p = strchr(method, ':')) != NULL) 505 *p = '\0'; 506 if (strcmp(method, authmethods[i]->name) != 0) 507 continue; 508 if (need_enable) { 509 if (authmethods[i]->enabled == NULL || 510 *(authmethods[i]->enabled) == 0) { 511 error("Disabled method \"%s\" in " 512 "AuthenticationMethods list \"%s\"", 513 method, _methods); 514 goto out; 515 } 516 } 517 found = 1; 518 break; 519 } 520 if (!found) { 521 error("Unknown authentication method \"%s\" in list", 522 method); 523 goto out; 524 } 525 } 526 ret = 0; 527 out: 528 free(omethods); 529 return ret; 530 } 531 532 /* 533 * Prune the AuthenticationMethods supplied in the configuration, removing 534 * any methods lists that include disabled methods. Note that this might 535 * leave authctxt->num_auth_methods == 0, even when multiple required auth 536 * has been requested. For this reason, all tests for whether multiple is 537 * enabled should consult options.num_auth_methods directly. 538 */ 539 int 540 auth2_setup_methods_lists(Authctxt *authctxt) 541 { 542 u_int i; 543 544 if (options.num_auth_methods == 0) 545 return 0; 546 debug3("%s: checking methods", __func__); 547 authctxt->auth_methods = xcalloc(options.num_auth_methods, 548 sizeof(*authctxt->auth_methods)); 549 authctxt->num_auth_methods = 0; 550 for (i = 0; i < options.num_auth_methods; i++) { 551 if (auth2_methods_valid(options.auth_methods[i], 1) != 0) { 552 logit("Authentication methods list \"%s\" contains " 553 "disabled method, skipping", 554 options.auth_methods[i]); 555 continue; 556 } 557 debug("authentication methods list %d: %s", 558 authctxt->num_auth_methods, options.auth_methods[i]); 559 authctxt->auth_methods[authctxt->num_auth_methods++] = 560 xstrdup(options.auth_methods[i]); 561 } 562 if (authctxt->num_auth_methods == 0) { 563 error("No AuthenticationMethods left after eliminating " 564 "disabled methods"); 565 return -1; 566 } 567 return 0; 568 } 569 570 static int 571 list_starts_with(const char *methods, const char *method, 572 const char *submethod) 573 { 574 size_t l = strlen(method); 575 int match; 576 const char *p; 577 578 if (strncmp(methods, method, l) != 0) 579 return MATCH_NONE; 580 p = methods + l; 581 match = MATCH_METHOD; 582 if (*p == ':') { 583 if (!submethod) 584 return MATCH_PARTIAL; 585 l = strlen(submethod); 586 p += 1; 587 if (strncmp(submethod, p, l)) 588 return MATCH_NONE; 589 p += l; 590 match = MATCH_BOTH; 591 } 592 if (*p != ',' && *p != '\0') 593 return MATCH_NONE; 594 return match; 595 } 596 597 /* 598 * Remove method from the start of a comma-separated list of methods. 599 * Returns 0 if the list of methods did not start with that method or 1 600 * if it did. 601 */ 602 static int 603 remove_method(char **methods, const char *method, const char *submethod) 604 { 605 char *omethods = *methods, *p; 606 size_t l = strlen(method); 607 int match; 608 609 match = list_starts_with(omethods, method, submethod); 610 if (match != MATCH_METHOD && match != MATCH_BOTH) 611 return 0; 612 p = omethods + l; 613 if (submethod && match == MATCH_BOTH) 614 p += 1 + strlen(submethod); /* include colon */ 615 if (*p == ',') 616 p++; 617 *methods = xstrdup(p); 618 free(omethods); 619 return 1; 620 } 621 622 /* 623 * Called after successful authentication. Will remove the successful method 624 * from the start of each list in which it occurs. If it was the last method 625 * in any list, then authentication is deemed successful. 626 * Returns 1 if the method completed any authentication list or 0 otherwise. 627 */ 628 int 629 auth2_update_methods_lists(Authctxt *authctxt, const char *method, 630 const char *submethod) 631 { 632 u_int i, found = 0; 633 634 debug3("%s: updating methods list after \"%s\"", __func__, method); 635 for (i = 0; i < authctxt->num_auth_methods; i++) { 636 if (!remove_method(&(authctxt->auth_methods[i]), method, 637 submethod)) 638 continue; 639 found = 1; 640 if (*authctxt->auth_methods[i] == '\0') { 641 debug2("authentication methods list %d complete", i); 642 return 1; 643 } 644 debug3("authentication methods list %d remaining: \"%s\"", 645 i, authctxt->auth_methods[i]); 646 } 647 /* This should not happen, but would be bad if it did */ 648 if (!found) 649 fatal("%s: method not in AuthenticationMethods", __func__); 650 return 0; 651 } 652 653 /* Reset method-specific information */ 654 void auth2_authctxt_reset_info(Authctxt *authctxt) 655 { 656 sshkey_free(authctxt->auth_method_key); 657 free(authctxt->auth_method_info); 658 authctxt->auth_method_key = NULL; 659 authctxt->auth_method_info = NULL; 660 } 661 662 /* Record auth method-specific information for logs */ 663 void 664 auth2_record_info(Authctxt *authctxt, const char *fmt, ...) 665 { 666 va_list ap; 667 int i; 668 669 free(authctxt->auth_method_info); 670 authctxt->auth_method_info = NULL; 671 672 va_start(ap, fmt); 673 i = vasprintf(&authctxt->auth_method_info, fmt, ap); 674 va_end(ap); 675 676 if (i < 0 || authctxt->auth_method_info == NULL) 677 fatal("%s: vasprintf failed", __func__); 678 } 679 680 /* 681 * Records a public key used in authentication. This is used for logging 682 * and to ensure that the same key is not subsequently accepted again for 683 * multiple authentication. 684 */ 685 void 686 auth2_record_key(Authctxt *authctxt, int authenticated, 687 const struct sshkey *key) 688 { 689 struct sshkey **tmp, *dup; 690 int r; 691 692 if ((r = sshkey_demote(key, &dup)) != 0) 693 fatal("%s: copy key: %s", __func__, ssh_err(r)); 694 sshkey_free(authctxt->auth_method_key); 695 authctxt->auth_method_key = dup; 696 697 if (!authenticated) 698 return; 699 700 /* If authenticated, make sure we don't accept this key again */ 701 if ((r = sshkey_demote(key, &dup)) != 0) 702 fatal("%s: copy key: %s", __func__, ssh_err(r)); 703 if (authctxt->nprev_keys >= INT_MAX || 704 (tmp = recallocarray(authctxt->prev_keys, authctxt->nprev_keys, 705 authctxt->nprev_keys + 1, sizeof(*authctxt->prev_keys))) == NULL) 706 fatal("%s: reallocarray failed", __func__); 707 authctxt->prev_keys = tmp; 708 authctxt->prev_keys[authctxt->nprev_keys] = dup; 709 authctxt->nprev_keys++; 710 711 } 712 713 /* Checks whether a key has already been previously used for authentication */ 714 int 715 auth2_key_already_used(Authctxt *authctxt, const struct sshkey *key) 716 { 717 u_int i; 718 char *fp; 719 720 for (i = 0; i < authctxt->nprev_keys; i++) { 721 if (sshkey_equal_public(key, authctxt->prev_keys[i])) { 722 fp = sshkey_fingerprint(authctxt->prev_keys[i], 723 options.fingerprint_hash, SSH_FP_DEFAULT); 724 debug3("%s: key already used: %s %s", __func__, 725 sshkey_type(authctxt->prev_keys[i]), 726 fp == NULL ? "UNKNOWN" : fp); 727 free(fp); 728 return 1; 729 } 730 } 731 return 0; 732 } 733 734 /* 735 * Updates authctxt->session_info with details of authentication. Should be 736 * whenever an authentication method succeeds. 737 */ 738 void 739 auth2_update_session_info(Authctxt *authctxt, const char *method, 740 const char *submethod) 741 { 742 int r; 743 744 if (authctxt->session_info == NULL) { 745 if ((authctxt->session_info = sshbuf_new()) == NULL) 746 fatal("%s: sshbuf_new", __func__); 747 } 748 749 /* Append method[/submethod] */ 750 if ((r = sshbuf_putf(authctxt->session_info, "%s%s%s", 751 method, submethod == NULL ? "" : "/", 752 submethod == NULL ? "" : submethod)) != 0) 753 fatal("%s: append method: %s", __func__, ssh_err(r)); 754 755 /* Append key if present */ 756 if (authctxt->auth_method_key != NULL) { 757 if ((r = sshbuf_put_u8(authctxt->session_info, ' ')) != 0 || 758 (r = sshkey_format_text(authctxt->auth_method_key, 759 authctxt->session_info)) != 0) 760 fatal("%s: append key: %s", __func__, ssh_err(r)); 761 } 762 763 if (authctxt->auth_method_info != NULL) { 764 /* Ensure no ambiguity here */ 765 if (strchr(authctxt->auth_method_info, '\n') != NULL) 766 fatal("%s: auth_method_info contains \\n", __func__); 767 if ((r = sshbuf_put_u8(authctxt->session_info, ' ')) != 0 || 768 (r = sshbuf_putf(authctxt->session_info, "%s", 769 authctxt->auth_method_info)) != 0) { 770 fatal("%s: append method info: %s", 771 __func__, ssh_err(r)); 772 } 773 } 774 if ((r = sshbuf_put_u8(authctxt->session_info, '\n')) != 0) 775 fatal("%s: append: %s", __func__, ssh_err(r)); 776 } 777 778