1 /* $OpenBSD: auth.c,v 1.164 2026/02/11 22:57:16 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 28 #include <sys/types.h> 29 #include <sys/stat.h> 30 #include <sys/socket.h> 31 #include <sys/wait.h> 32 33 #include <netinet/in.h> 34 35 #include <stdlib.h> 36 #include <errno.h> 37 #include <fcntl.h> 38 #include <paths.h> 39 #include <pwd.h> 40 #ifdef HAVE_LOGIN_H 41 #include <login.h> 42 #endif 43 #ifdef USE_SHADOW 44 #include <shadow.h> 45 #endif 46 #include <stdarg.h> 47 #include <stdio.h> 48 #include <string.h> 49 #include <unistd.h> 50 #include <limits.h> 51 #include <netdb.h> 52 #include <time.h> 53 54 #include "xmalloc.h" 55 #include "match.h" 56 #include "groupaccess.h" 57 #include "log.h" 58 #include "sshbuf.h" 59 #include "misc.h" 60 #include "servconf.h" 61 #include "sshkey.h" 62 #include "hostfile.h" 63 #include "auth.h" 64 #include "auth-options.h" 65 #include "canohost.h" 66 #include "uidswap.h" 67 #include "packet.h" 68 #include "loginrec.h" 69 #ifdef GSSAPI 70 #include "ssh-gss.h" 71 #endif 72 #include "authfile.h" 73 #include "monitor_wrap.h" 74 #include "ssherr.h" 75 #include "channels.h" 76 #include "blocklist_client.h" 77 78 /* import */ 79 extern ServerOptions options; 80 extern struct include_list includes; 81 extern struct sshbuf *loginmsg; 82 extern struct passwd *privsep_pw; 83 extern struct sshauthopt *auth_opts; 84 85 /* Debugging messages */ 86 static struct sshbuf *auth_debug; 87 88 /* 89 * Check if the user is allowed to log in via ssh. If user is listed 90 * in DenyUsers or one of user's groups is listed in DenyGroups, false 91 * will be returned. If AllowUsers isn't empty and user isn't listed 92 * there, or if AllowGroups isn't empty and one of user's groups isn't 93 * listed there, false will be returned. 94 * If the user's shell is not executable, false will be returned. 95 * Otherwise true is returned. 96 */ 97 int 98 allowed_user(struct ssh *ssh, struct passwd * pw) 99 { 100 struct stat st; 101 const char *hostname = NULL, *ipaddr = NULL; 102 int r; 103 u_int i; 104 105 /* Shouldn't be called if pw is NULL, but better safe than sorry... */ 106 if (!pw || !pw->pw_name) 107 return 0; 108 109 if (!options.use_pam && platform_locked_account(pw)) { 110 logit("User %.100s not allowed because account is locked", 111 pw->pw_name); 112 return 0; 113 } 114 115 /* 116 * Deny if shell does not exist or is not executable unless we 117 * are chrooting. 118 */ 119 if (options.chroot_directory == NULL || 120 strcasecmp(options.chroot_directory, "none") == 0) { 121 char *shell = xstrdup((pw->pw_shell[0] == '\0') ? 122 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ 123 124 if (stat(shell, &st) == -1) { 125 logit("User %.100s not allowed because shell %.100s " 126 "does not exist", pw->pw_name, shell); 127 free(shell); 128 return 0; 129 } 130 if (S_ISREG(st.st_mode) == 0 || 131 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { 132 logit("User %.100s not allowed because shell %.100s " 133 "is not executable", pw->pw_name, shell); 134 free(shell); 135 return 0; 136 } 137 free(shell); 138 } 139 140 if (options.num_deny_users > 0 || options.num_allow_users > 0 || 141 options.num_deny_groups > 0 || options.num_allow_groups > 0) { 142 hostname = auth_get_canonical_hostname(ssh, options.use_dns); 143 ipaddr = ssh_remote_ipaddr(ssh); 144 } 145 146 /* Return false if user is listed in DenyUsers */ 147 if (options.num_deny_users > 0) { 148 for (i = 0; i < options.num_deny_users; i++) { 149 r = match_user(pw->pw_name, hostname, ipaddr, 150 options.deny_users[i]); 151 if (r < 0) { 152 fatal("Invalid DenyUsers pattern \"%.100s\"", 153 options.deny_users[i]); 154 } else if (r != 0) { 155 logit("User %.100s from %.100s not allowed " 156 "because listed in DenyUsers", 157 pw->pw_name, hostname); 158 return 0; 159 } 160 } 161 } 162 /* Return false if AllowUsers isn't empty and user isn't listed there */ 163 if (options.num_allow_users > 0) { 164 for (i = 0; i < options.num_allow_users; i++) { 165 r = match_user(pw->pw_name, hostname, ipaddr, 166 options.allow_users[i]); 167 if (r < 0) { 168 fatal("Invalid AllowUsers pattern \"%.100s\"", 169 options.allow_users[i]); 170 } else if (r == 1) 171 break; 172 } 173 /* i < options.num_allow_users iff we break for loop */ 174 if (i >= options.num_allow_users) { 175 logit("User %.100s from %.100s not allowed because " 176 "not listed in AllowUsers", pw->pw_name, hostname); 177 return 0; 178 } 179 } 180 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { 181 /* Get the user's group access list (primary and supplementary) */ 182 if (ga_init(pw->pw_name, pw->pw_gid) == 0) { 183 logit("User %.100s from %.100s not allowed because " 184 "not in any group", pw->pw_name, hostname); 185 return 0; 186 } 187 188 /* Return false if one of user's groups is listed in DenyGroups */ 189 if (options.num_deny_groups > 0) 190 if (ga_match(options.deny_groups, 191 options.num_deny_groups)) { 192 ga_free(); 193 logit("User %.100s from %.100s not allowed " 194 "because a group is listed in DenyGroups", 195 pw->pw_name, hostname); 196 return 0; 197 } 198 /* 199 * Return false if AllowGroups isn't empty and one of user's groups 200 * isn't listed there 201 */ 202 if (options.num_allow_groups > 0) 203 if (!ga_match(options.allow_groups, 204 options.num_allow_groups)) { 205 ga_free(); 206 logit("User %.100s from %.100s not allowed " 207 "because none of user's groups are listed " 208 "in AllowGroups", pw->pw_name, hostname); 209 return 0; 210 } 211 ga_free(); 212 } 213 214 #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER 215 if (!sys_auth_allowed_user(pw, loginmsg)) 216 return 0; 217 #endif 218 219 /* We found no reason not to let this user try to log on... */ 220 return 1; 221 } 222 223 /* 224 * Formats any key left in authctxt->auth_method_key for inclusion in 225 * auth_log()'s message. Also includes authxtct->auth_method_info if present. 226 */ 227 static char * 228 format_method_key(Authctxt *authctxt) 229 { 230 const struct sshkey *key = authctxt->auth_method_key; 231 const char *methinfo = authctxt->auth_method_info; 232 char *fp, *cafp, *ret = NULL; 233 234 if (key == NULL) 235 return NULL; 236 237 if (sshkey_is_cert(key)) { 238 fp = sshkey_fingerprint(key, 239 options.fingerprint_hash, SSH_FP_DEFAULT); 240 cafp = sshkey_fingerprint(key->cert->signature_key, 241 options.fingerprint_hash, SSH_FP_DEFAULT); 242 xasprintf(&ret, "%s %s ID %s (serial %llu) CA %s %s%s%s", 243 sshkey_type(key), fp == NULL ? "(null)" : fp, 244 key->cert->key_id, 245 (unsigned long long)key->cert->serial, 246 sshkey_type(key->cert->signature_key), 247 cafp == NULL ? "(null)" : cafp, 248 methinfo == NULL ? "" : ", ", 249 methinfo == NULL ? "" : methinfo); 250 free(fp); 251 free(cafp); 252 } else { 253 fp = sshkey_fingerprint(key, options.fingerprint_hash, 254 SSH_FP_DEFAULT); 255 xasprintf(&ret, "%s %s%s%s", sshkey_type(key), 256 fp == NULL ? "(null)" : fp, 257 methinfo == NULL ? "" : ", ", 258 methinfo == NULL ? "" : methinfo); 259 free(fp); 260 } 261 return ret; 262 } 263 264 void 265 auth_log(struct ssh *ssh, int authenticated, int partial, 266 const char *method, const char *submethod) 267 { 268 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 269 int level = SYSLOG_LEVEL_VERBOSE; 270 const char *authmsg; 271 char *extra = NULL; 272 273 if (!mm_is_monitor() && !authctxt->postponed) 274 return; 275 276 /* Raise logging level */ 277 if (authenticated == 1 || 278 !authctxt->valid || 279 authctxt->failures >= options.max_authtries / 2 || 280 strcmp(method, "password") == 0) 281 level = SYSLOG_LEVEL_INFO; 282 283 if (authctxt->postponed) 284 authmsg = "Postponed"; 285 else if (partial) 286 authmsg = "Partial"; 287 else { 288 authmsg = authenticated ? "Accepted" : "Failed"; 289 if (authenticated) 290 BLOCKLIST_NOTIFY(ssh, BLOCKLIST_AUTH_OK, 291 "Authenticated"); 292 } 293 294 if ((extra = format_method_key(authctxt)) == NULL) { 295 if (authctxt->auth_method_info != NULL) 296 extra = xstrdup(authctxt->auth_method_info); 297 } 298 299 do_log2(level, "%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s", 300 authmsg, 301 method, 302 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, 303 authctxt->valid ? "" : "invalid user ", 304 authctxt->user, 305 ssh_remote_ipaddr(ssh), 306 ssh_remote_port(ssh), 307 extra != NULL ? ": " : "", 308 extra != NULL ? extra : ""); 309 310 free(extra); 311 312 #if defined(CUSTOM_FAILED_LOGIN) || defined(SSH_AUDIT_EVENTS) 313 if (authenticated == 0 && !(authctxt->postponed || partial)) { 314 /* Log failed login attempt */ 315 # ifdef CUSTOM_FAILED_LOGIN 316 if (strcmp(method, "password") == 0 || 317 strncmp(method, "keyboard-interactive", 20) == 0 || 318 strcmp(method, "challenge-response") == 0) 319 record_failed_login(ssh, authctxt->user, 320 auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); 321 # endif 322 # ifdef SSH_AUDIT_EVENTS 323 audit_event(ssh, audit_classify_auth(method)); 324 # endif 325 } 326 #endif 327 #if defined(CUSTOM_FAILED_LOGIN) && defined(WITH_AIXAUTHENTICATE) 328 if (authenticated) 329 sys_auth_record_login(authctxt->user, 330 auth_get_canonical_hostname(ssh, options.use_dns), "ssh", 331 loginmsg); 332 #endif 333 } 334 335 void 336 auth_maxtries_exceeded(struct ssh *ssh) 337 { 338 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 339 340 BLOCKLIST_NOTIFY(ssh, BLOCKLIST_AUTH_FAIL, "Maximum attempts exceeded"); 341 error("maximum authentication attempts exceeded for " 342 "%s%.100s from %.200s port %d ssh2", 343 authctxt->valid ? "" : "invalid user ", 344 authctxt->user, 345 ssh_remote_ipaddr(ssh), 346 ssh_remote_port(ssh)); 347 ssh_packet_disconnect(ssh, "Too many authentication failures"); 348 /* NOTREACHED */ 349 } 350 351 /* 352 * Check whether root logins are disallowed. 353 */ 354 int 355 auth_root_allowed(struct ssh *ssh, const char *method) 356 { 357 switch (options.permit_root_login) { 358 case PERMIT_YES: 359 return 1; 360 case PERMIT_NO_PASSWD: 361 if (strcmp(method, "publickey") == 0 || 362 strcmp(method, "hostbased") == 0 || 363 strcmp(method, "gssapi-with-mic") == 0) 364 return 1; 365 break; 366 case PERMIT_FORCED_ONLY: 367 if (auth_opts->force_command != NULL) { 368 logit("Root login accepted for forced command."); 369 return 1; 370 } 371 break; 372 } 373 logit("ROOT LOGIN REFUSED FROM %.200s port %d", 374 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 375 return 0; 376 } 377 378 379 /* 380 * Given a template and a passwd structure, build a filename 381 * by substituting % tokenised options. Currently, %% becomes '%', 382 * %h becomes the home directory and %u the username. 383 * 384 * This returns a buffer allocated by xmalloc. 385 */ 386 char * 387 expand_authorized_keys(const char *filename, struct passwd *pw) 388 { 389 char *file, uidstr[32], ret[PATH_MAX]; 390 int i; 391 392 snprintf(uidstr, sizeof(uidstr), "%llu", 393 (unsigned long long)pw->pw_uid); 394 file = percent_expand(filename, "h", pw->pw_dir, 395 "u", pw->pw_name, "U", uidstr, (char *)NULL); 396 397 /* 398 * Ensure that filename starts anchored. If not, be backward 399 * compatible and prepend the '%h/' 400 */ 401 if (path_absolute(file)) 402 return (file); 403 404 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); 405 if (i < 0 || (size_t)i >= sizeof(ret)) 406 fatal("expand_authorized_keys: path too long"); 407 free(file); 408 return (xstrdup(ret)); 409 } 410 411 char * 412 authorized_principals_file(struct passwd *pw) 413 { 414 if (options.authorized_principals_file == NULL) 415 return NULL; 416 return expand_authorized_keys(options.authorized_principals_file, pw); 417 } 418 419 /* return ok if key exists in sysfile or userfile */ 420 HostStatus 421 check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host, 422 const char *sysfile, const char *userfile) 423 { 424 char *user_hostfile; 425 struct stat st; 426 HostStatus host_status; 427 struct hostkeys *hostkeys; 428 const struct hostkey_entry *found; 429 430 hostkeys = init_hostkeys(); 431 load_hostkeys(hostkeys, host, sysfile, 0); 432 if (userfile != NULL) { 433 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); 434 if (options.strict_modes && 435 (stat(user_hostfile, &st) == 0) && 436 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || 437 (st.st_mode & 022) != 0)) { 438 logit("Authentication refused for %.100s: " 439 "bad owner or modes for %.200s", 440 pw->pw_name, user_hostfile); 441 auth_debug_add("Ignored %.200s: bad ownership or modes", 442 user_hostfile); 443 } else { 444 temporarily_use_uid(pw); 445 load_hostkeys(hostkeys, host, user_hostfile, 0); 446 restore_uid(); 447 } 448 free(user_hostfile); 449 } 450 host_status = check_key_in_hostkeys(hostkeys, key, &found); 451 if (host_status == HOST_REVOKED) 452 error("WARNING: revoked key for %s attempted authentication", 453 host); 454 else if (host_status == HOST_OK) 455 debug_f("key for %s found at %s:%ld", 456 found->host, found->file, found->line); 457 else 458 debug_f("key for host %s not found", host); 459 460 free_hostkeys(hostkeys); 461 462 return host_status; 463 } 464 465 struct passwd * 466 getpwnamallow(struct ssh *ssh, const char *user) 467 { 468 #ifdef HAVE_LOGIN_CAP 469 extern login_cap_t *lc; 470 #ifdef HAVE_AUTH_HOSTOK 471 const char *from_host, *from_ip; 472 #endif 473 #ifdef BSD_AUTH 474 auth_session_t *as; 475 #endif 476 #endif 477 struct passwd *pw; 478 struct connection_info *ci; 479 u_int i; 480 481 ci = server_get_connection_info(ssh, 1, options.use_dns); 482 ci->user = user; 483 ci->user_invalid = getpwnam(user) == NULL; 484 parse_server_match_config(&options, &includes, ci); 485 log_change_level(options.log_level); 486 log_verbose_reset(); 487 for (i = 0; i < options.num_log_verbose; i++) 488 log_verbose_add(options.log_verbose[i]); 489 server_process_permitopen(ssh); 490 491 #if defined(_AIX) && defined(HAVE_SETAUTHDB) 492 aix_setauthdb(user); 493 #endif 494 495 pw = getpwnam(user); 496 497 #if defined(_AIX) && defined(HAVE_SETAUTHDB) 498 aix_restoreauthdb(); 499 #endif 500 if (pw == NULL) { 501 BLOCKLIST_NOTIFY(ssh, BLOCKLIST_AUTH_FAIL, "Invalid user"); 502 logit("Invalid user %.100s from %.100s port %d", 503 user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 504 #ifdef CUSTOM_FAILED_LOGIN 505 record_failed_login(ssh, user, 506 auth_get_canonical_hostname(ssh, options.use_dns), "ssh"); 507 #endif 508 #ifdef SSH_AUDIT_EVENTS 509 audit_event(ssh, SSH_INVALID_USER); 510 #endif /* SSH_AUDIT_EVENTS */ 511 return (NULL); 512 } 513 if (!allowed_user(ssh, pw)) 514 return (NULL); 515 #ifdef HAVE_LOGIN_CAP 516 if ((lc = login_getpwclass(pw)) == NULL) { 517 debug("unable to get login class: %s", user); 518 return (NULL); 519 } 520 #ifdef HAVE_AUTH_HOSTOK 521 from_host = auth_get_canonical_hostname(ssh, options.use_dns); 522 from_ip = ssh_remote_ipaddr(ssh); 523 if (!auth_hostok(lc, from_host, from_ip)) { 524 debug("Denied connection for %.200s from %.200s [%.200s].", 525 pw->pw_name, from_host, from_ip); 526 return (NULL); 527 } 528 #endif /* HAVE_AUTH_HOSTOK */ 529 #ifdef HAVE_AUTH_TIMEOK 530 if (!auth_timeok(lc, time(NULL))) { 531 debug("LOGIN %.200s REFUSED (TIME)", pw->pw_name); 532 return (NULL); 533 } 534 #endif /* HAVE_AUTH_TIMEOK */ 535 #ifdef BSD_AUTH 536 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || 537 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { 538 debug("Approval failure for %s", user); 539 pw = NULL; 540 } 541 if (as != NULL) 542 auth_close(as); 543 #endif 544 #endif 545 if (pw != NULL) 546 return (pwcopy(pw)); 547 return (NULL); 548 } 549 550 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ 551 int 552 auth_key_is_revoked(struct sshkey *key) 553 { 554 char *fp = NULL; 555 u_int i; 556 int r; 557 558 if (options.num_revoked_keys_files == 0) 559 return 0; 560 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 561 SSH_FP_DEFAULT)) == NULL) { 562 r = SSH_ERR_ALLOC_FAIL; 563 error_fr(r, "fingerprint key"); 564 goto out; 565 } 566 567 for (i = 0; i < options.num_revoked_keys_files; i++) { 568 r = sshkey_check_revoked(key, options.revoked_keys_files[i]); 569 switch (r) { 570 case 0: 571 break; /* not revoked */ 572 case SSH_ERR_KEY_REVOKED: 573 error("Authentication key %s %s revoked by file %s", 574 sshkey_type(key), fp, 575 options.revoked_keys_files[i]); 576 goto out; 577 default: 578 error_r(r, "Error checking authentication key %s %s in " 579 "revoked keys file %s", sshkey_type(key), fp, 580 options.revoked_keys_files[i]); 581 goto out; 582 } 583 } 584 585 /* Success */ 586 r = 0; 587 588 out: 589 free(fp); 590 return r == 0 ? 0 : 1; 591 } 592 593 void 594 auth_debug_add(const char *fmt,...) 595 { 596 char buf[1024]; 597 va_list args; 598 int r; 599 600 va_start(args, fmt); 601 vsnprintf(buf, sizeof(buf), fmt, args); 602 va_end(args); 603 debug3("%s", buf); 604 if (auth_debug != NULL) 605 if ((r = sshbuf_put_cstring(auth_debug, buf)) != 0) 606 fatal_fr(r, "sshbuf_put_cstring"); 607 } 608 609 void 610 auth_debug_send(struct ssh *ssh) 611 { 612 char *msg; 613 int r; 614 615 if (auth_debug == NULL) 616 return; 617 while (sshbuf_len(auth_debug) != 0) { 618 if ((r = sshbuf_get_cstring(auth_debug, &msg, NULL)) != 0) 619 fatal_fr(r, "sshbuf_get_cstring"); 620 ssh_packet_send_debug(ssh, "%s", msg); 621 free(msg); 622 } 623 } 624 625 void 626 auth_debug_reset(void) 627 { 628 if (auth_debug != NULL) 629 sshbuf_reset(auth_debug); 630 else if ((auth_debug = sshbuf_new()) == NULL) 631 fatal_f("sshbuf_new failed"); 632 } 633 634 struct passwd * 635 fakepw(void) 636 { 637 static int done = 0; 638 static struct passwd fake; 639 const char hashchars[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZ" 640 "abcdefghijklmnopqrstuvwxyz0123456789"; /* from bcrypt.c */ 641 char *cp; 642 643 if (done) 644 return (&fake); 645 646 memset(&fake, 0, sizeof(fake)); 647 fake.pw_name = "NOUSER"; 648 fake.pw_passwd = xstrdup("$2a$10$" 649 "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); 650 for (cp = fake.pw_passwd + 7; *cp != '\0'; cp++) 651 *cp = hashchars[arc4random_uniform(sizeof(hashchars) - 1)]; 652 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS 653 fake.pw_gecos = "NOUSER"; 654 #endif 655 fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid; 656 fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid; 657 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS 658 fake.pw_class = ""; 659 #endif 660 fake.pw_dir = "/nonexist"; 661 fake.pw_shell = "/nonexist"; 662 done = 1; 663 664 return (&fake); 665 } 666 667 /* 668 * Return the canonical name of the host in the other side of the current 669 * connection. The host name is cached, so it is efficient to call this 670 * several times. 671 */ 672 673 const char * 674 auth_get_canonical_hostname(struct ssh *ssh, int use_dns) 675 { 676 static char *dnsname; 677 678 if (!use_dns) 679 return ssh_remote_ipaddr(ssh); 680 if (dnsname != NULL) 681 return dnsname; 682 dnsname = ssh_remote_hostname(ssh); 683 return dnsname; 684 } 685 686 /* These functions link key/cert options to the auth framework */ 687 688 /* Log sshauthopt options locally and (optionally) for remote transmission */ 689 void 690 auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote) 691 { 692 int do_env = options.permit_user_env && opts->nenv > 0; 693 int do_permitopen = opts->npermitopen > 0 && 694 (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0; 695 int do_permitlisten = opts->npermitlisten > 0 && 696 (options.allow_tcp_forwarding & FORWARD_REMOTE) != 0; 697 size_t i; 698 char msg[1024], buf[64]; 699 700 snprintf(buf, sizeof(buf), "%d", opts->force_tun_device); 701 /* Try to keep this alphabetically sorted */ 702 snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s", 703 opts->permit_agent_forwarding_flag ? " agent-forwarding" : "", 704 opts->force_command == NULL ? "" : " command", 705 do_env ? " environment" : "", 706 opts->valid_before == 0 ? "" : "expires", 707 opts->no_require_user_presence ? " no-touch-required" : "", 708 do_permitopen ? " permitopen" : "", 709 do_permitlisten ? " permitlisten" : "", 710 opts->permit_port_forwarding_flag ? " port-forwarding" : "", 711 opts->cert_principals == NULL ? "" : " principals", 712 opts->permit_pty_flag ? " pty" : "", 713 opts->require_verify ? " uv" : "", 714 opts->force_tun_device == -1 ? "" : " tun=", 715 opts->force_tun_device == -1 ? "" : buf, 716 opts->permit_user_rc ? " user-rc" : "", 717 opts->permit_x11_forwarding_flag ? " x11-forwarding" : ""); 718 719 debug("%s: %s", loc, msg); 720 if (do_remote) 721 auth_debug_add("%s: %s", loc, msg); 722 723 if (options.permit_user_env) { 724 for (i = 0; i < opts->nenv; i++) { 725 debug("%s: environment: %s", loc, opts->env[i]); 726 if (do_remote) { 727 auth_debug_add("%s: environment: %s", 728 loc, opts->env[i]); 729 } 730 } 731 } 732 733 /* Go into a little more details for the local logs. */ 734 if (opts->valid_before != 0) { 735 format_absolute_time(opts->valid_before, buf, sizeof(buf)); 736 debug("%s: expires at %s", loc, buf); 737 } 738 if (opts->cert_principals != NULL) { 739 debug("%s: authorized principals: \"%s\"", 740 loc, opts->cert_principals); 741 } 742 if (opts->force_command != NULL) 743 debug("%s: forced command: \"%s\"", loc, opts->force_command); 744 if (do_permitopen) { 745 for (i = 0; i < opts->npermitopen; i++) { 746 debug("%s: permitted open: %s", 747 loc, opts->permitopen[i]); 748 } 749 } 750 if (do_permitlisten) { 751 for (i = 0; i < opts->npermitlisten; i++) { 752 debug("%s: permitted listen: %s", 753 loc, opts->permitlisten[i]); 754 } 755 } 756 } 757 758 /* Activate a new set of key/cert options; merging with what is there. */ 759 int 760 auth_activate_options(struct ssh *ssh, struct sshauthopt *opts) 761 { 762 struct sshauthopt *old = auth_opts; 763 const char *emsg = NULL; 764 765 debug_f("setting new authentication options"); 766 if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) { 767 error("Inconsistent authentication options: %s", emsg); 768 return -1; 769 } 770 sshauthopt_free(old); 771 return 0; 772 } 773 774 /* Disable forwarding, etc for the session */ 775 void 776 auth_restrict_session(struct ssh *ssh) 777 { 778 struct sshauthopt *restricted; 779 780 debug_f("restricting session"); 781 782 /* A blank sshauthopt defaults to permitting nothing */ 783 if ((restricted = sshauthopt_new()) == NULL) 784 fatal_f("sshauthopt_new failed"); 785 restricted->permit_pty_flag = 1; 786 restricted->restricted = 1; 787 788 if (auth_activate_options(ssh, restricted) != 0) 789 fatal_f("failed to restrict session"); 790 sshauthopt_free(restricted); 791 } 792