1 /* $OpenBSD: auth.c,v 1.160 2023/03/05 05:34:09 dtucker 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 <sys/types.h> 27 #include <sys/stat.h> 28 #include <sys/socket.h> 29 #include <sys/wait.h> 30 31 #include <stdlib.h> 32 #include <errno.h> 33 #include <fcntl.h> 34 #include <login_cap.h> 35 #include <paths.h> 36 #include <pwd.h> 37 #include <stdarg.h> 38 #include <stdio.h> 39 #include <string.h> 40 #include <unistd.h> 41 #include <limits.h> 42 #include <netdb.h> 43 #include <time.h> 44 45 #include "xmalloc.h" 46 #include "match.h" 47 #include "groupaccess.h" 48 #include "log.h" 49 #include "sshbuf.h" 50 #include "misc.h" 51 #include "servconf.h" 52 #include "sshkey.h" 53 #include "hostfile.h" 54 #include "auth.h" 55 #include "auth-options.h" 56 #include "canohost.h" 57 #include "uidswap.h" 58 #include "packet.h" 59 #ifdef GSSAPI 60 #include "ssh-gss.h" 61 #endif 62 #include "authfile.h" 63 #include "monitor_wrap.h" 64 #include "ssherr.h" 65 #include "channels.h" 66 67 /* import */ 68 extern ServerOptions options; 69 extern struct include_list includes; 70 extern int use_privsep; 71 extern struct sshauthopt *auth_opts; 72 73 /* Debugging messages */ 74 static struct sshbuf *auth_debug; 75 76 /* 77 * Check if the user is allowed to log in via ssh. If user is listed 78 * in DenyUsers or one of user's groups is listed in DenyGroups, false 79 * will be returned. If AllowUsers isn't empty and user isn't listed 80 * there, or if AllowGroups isn't empty and one of user's groups isn't 81 * listed there, false will be returned. 82 * If the user's shell is not executable, false will be returned. 83 * Otherwise true is returned. 84 */ 85 int 86 allowed_user(struct ssh *ssh, struct passwd * pw) 87 { 88 struct stat st; 89 const char *hostname = NULL, *ipaddr = NULL; 90 int r; 91 u_int i; 92 93 /* Shouldn't be called if pw is NULL, but better safe than sorry... */ 94 if (!pw || !pw->pw_name) 95 return 0; 96 97 /* 98 * Deny if shell does not exist or is not executable unless we 99 * are chrooting. 100 */ 101 if (options.chroot_directory == NULL || 102 strcasecmp(options.chroot_directory, "none") == 0) { 103 char *shell = xstrdup((pw->pw_shell[0] == '\0') ? 104 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ 105 106 if (stat(shell, &st) == -1) { 107 logit("User %.100s not allowed because shell %.100s " 108 "does not exist", pw->pw_name, shell); 109 free(shell); 110 return 0; 111 } 112 if (S_ISREG(st.st_mode) == 0 || 113 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { 114 logit("User %.100s not allowed because shell %.100s " 115 "is not executable", pw->pw_name, shell); 116 free(shell); 117 return 0; 118 } 119 free(shell); 120 } 121 122 if (options.num_deny_users > 0 || options.num_allow_users > 0 || 123 options.num_deny_groups > 0 || options.num_allow_groups > 0) { 124 hostname = auth_get_canonical_hostname(ssh, options.use_dns); 125 ipaddr = ssh_remote_ipaddr(ssh); 126 } 127 128 /* Return false if user is listed in DenyUsers */ 129 if (options.num_deny_users > 0) { 130 for (i = 0; i < options.num_deny_users; i++) { 131 r = match_user(pw->pw_name, hostname, ipaddr, 132 options.deny_users[i]); 133 if (r < 0) { 134 fatal("Invalid DenyUsers pattern \"%.100s\"", 135 options.deny_users[i]); 136 } else if (r != 0) { 137 logit("User %.100s from %.100s not allowed " 138 "because listed in DenyUsers", 139 pw->pw_name, hostname); 140 return 0; 141 } 142 } 143 } 144 /* Return false if AllowUsers isn't empty and user isn't listed there */ 145 if (options.num_allow_users > 0) { 146 for (i = 0; i < options.num_allow_users; i++) { 147 r = match_user(pw->pw_name, hostname, ipaddr, 148 options.allow_users[i]); 149 if (r < 0) { 150 fatal("Invalid AllowUsers pattern \"%.100s\"", 151 options.allow_users[i]); 152 } else if (r == 1) 153 break; 154 } 155 /* i < options.num_allow_users iff we break for loop */ 156 if (i >= options.num_allow_users) { 157 logit("User %.100s from %.100s not allowed because " 158 "not listed in AllowUsers", pw->pw_name, hostname); 159 return 0; 160 } 161 } 162 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { 163 /* Get the user's group access list (primary and supplementary) */ 164 if (ga_init(pw->pw_name, pw->pw_gid) == 0) { 165 logit("User %.100s from %.100s not allowed because " 166 "not in any group", pw->pw_name, hostname); 167 return 0; 168 } 169 170 /* Return false if one of user's groups is listed in DenyGroups */ 171 if (options.num_deny_groups > 0) 172 if (ga_match(options.deny_groups, 173 options.num_deny_groups)) { 174 ga_free(); 175 logit("User %.100s from %.100s not allowed " 176 "because a group is listed in DenyGroups", 177 pw->pw_name, hostname); 178 return 0; 179 } 180 /* 181 * Return false if AllowGroups isn't empty and one of user's groups 182 * isn't listed there 183 */ 184 if (options.num_allow_groups > 0) 185 if (!ga_match(options.allow_groups, 186 options.num_allow_groups)) { 187 ga_free(); 188 logit("User %.100s from %.100s not allowed " 189 "because none of user's groups are listed " 190 "in AllowGroups", pw->pw_name, hostname); 191 return 0; 192 } 193 ga_free(); 194 } 195 /* We found no reason not to let this user try to log on... */ 196 return 1; 197 } 198 199 /* 200 * Formats any key left in authctxt->auth_method_key for inclusion in 201 * auth_log()'s message. Also includes authxtct->auth_method_info if present. 202 */ 203 static char * 204 format_method_key(Authctxt *authctxt) 205 { 206 const struct sshkey *key = authctxt->auth_method_key; 207 const char *methinfo = authctxt->auth_method_info; 208 char *fp, *cafp, *ret = NULL; 209 210 if (key == NULL) 211 return NULL; 212 213 if (sshkey_is_cert(key)) { 214 fp = sshkey_fingerprint(key, 215 options.fingerprint_hash, SSH_FP_DEFAULT); 216 cafp = sshkey_fingerprint(key->cert->signature_key, 217 options.fingerprint_hash, SSH_FP_DEFAULT); 218 xasprintf(&ret, "%s %s ID %s (serial %llu) CA %s %s%s%s", 219 sshkey_type(key), fp == NULL ? "(null)" : fp, 220 key->cert->key_id, 221 (unsigned long long)key->cert->serial, 222 sshkey_type(key->cert->signature_key), 223 cafp == NULL ? "(null)" : cafp, 224 methinfo == NULL ? "" : ", ", 225 methinfo == NULL ? "" : methinfo); 226 free(fp); 227 free(cafp); 228 } else { 229 fp = sshkey_fingerprint(key, options.fingerprint_hash, 230 SSH_FP_DEFAULT); 231 xasprintf(&ret, "%s %s%s%s", sshkey_type(key), 232 fp == NULL ? "(null)" : fp, 233 methinfo == NULL ? "" : ", ", 234 methinfo == NULL ? "" : methinfo); 235 free(fp); 236 } 237 return ret; 238 } 239 240 void 241 auth_log(struct ssh *ssh, int authenticated, int partial, 242 const char *method, const char *submethod) 243 { 244 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 245 int level = SYSLOG_LEVEL_VERBOSE; 246 const char *authmsg; 247 char *extra = NULL; 248 249 if (use_privsep && !mm_is_monitor() && !authctxt->postponed) 250 return; 251 252 /* Raise logging level */ 253 if (authenticated == 1 || 254 !authctxt->valid || 255 authctxt->failures >= options.max_authtries / 2 || 256 strcmp(method, "password") == 0) 257 level = SYSLOG_LEVEL_INFO; 258 259 if (authctxt->postponed) 260 authmsg = "Postponed"; 261 else if (partial) 262 authmsg = "Partial"; 263 else 264 authmsg = authenticated ? "Accepted" : "Failed"; 265 266 if ((extra = format_method_key(authctxt)) == NULL) { 267 if (authctxt->auth_method_info != NULL) 268 extra = xstrdup(authctxt->auth_method_info); 269 } 270 271 do_log2(level, "%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s", 272 authmsg, 273 method, 274 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, 275 authctxt->valid ? "" : "invalid user ", 276 authctxt->user, 277 ssh_remote_ipaddr(ssh), 278 ssh_remote_port(ssh), 279 extra != NULL ? ": " : "", 280 extra != NULL ? extra : ""); 281 282 free(extra); 283 } 284 285 void 286 auth_maxtries_exceeded(struct ssh *ssh) 287 { 288 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 289 290 error("maximum authentication attempts exceeded for " 291 "%s%.100s from %.200s port %d ssh2", 292 authctxt->valid ? "" : "invalid user ", 293 authctxt->user, 294 ssh_remote_ipaddr(ssh), 295 ssh_remote_port(ssh)); 296 ssh_packet_disconnect(ssh, "Too many authentication failures"); 297 /* NOTREACHED */ 298 } 299 300 /* 301 * Check whether root logins are disallowed. 302 */ 303 int 304 auth_root_allowed(struct ssh *ssh, const char *method) 305 { 306 switch (options.permit_root_login) { 307 case PERMIT_YES: 308 return 1; 309 case PERMIT_NO_PASSWD: 310 if (strcmp(method, "publickey") == 0 || 311 strcmp(method, "hostbased") == 0 || 312 strcmp(method, "gssapi-with-mic") == 0) 313 return 1; 314 break; 315 case PERMIT_FORCED_ONLY: 316 if (auth_opts->force_command != NULL) { 317 logit("Root login accepted for forced command."); 318 return 1; 319 } 320 break; 321 } 322 logit("ROOT LOGIN REFUSED FROM %.200s port %d", 323 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 324 return 0; 325 } 326 327 328 /* 329 * Given a template and a passwd structure, build a filename 330 * by substituting % tokenised options. Currently, %% becomes '%', 331 * %h becomes the home directory and %u the username. 332 * 333 * This returns a buffer allocated by xmalloc. 334 */ 335 char * 336 expand_authorized_keys(const char *filename, struct passwd *pw) 337 { 338 char *file, uidstr[32], ret[PATH_MAX]; 339 int i; 340 341 snprintf(uidstr, sizeof(uidstr), "%llu", 342 (unsigned long long)pw->pw_uid); 343 file = percent_expand(filename, "h", pw->pw_dir, 344 "u", pw->pw_name, "U", uidstr, (char *)NULL); 345 346 /* 347 * Ensure that filename starts anchored. If not, be backward 348 * compatible and prepend the '%h/' 349 */ 350 if (path_absolute(file)) 351 return (file); 352 353 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); 354 if (i < 0 || (size_t)i >= sizeof(ret)) 355 fatal("expand_authorized_keys: path too long"); 356 free(file); 357 return (xstrdup(ret)); 358 } 359 360 char * 361 authorized_principals_file(struct passwd *pw) 362 { 363 if (options.authorized_principals_file == NULL) 364 return NULL; 365 return expand_authorized_keys(options.authorized_principals_file, pw); 366 } 367 368 /* return ok if key exists in sysfile or userfile */ 369 HostStatus 370 check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host, 371 const char *sysfile, const char *userfile) 372 { 373 char *user_hostfile; 374 struct stat st; 375 HostStatus host_status; 376 struct hostkeys *hostkeys; 377 const struct hostkey_entry *found; 378 379 hostkeys = init_hostkeys(); 380 load_hostkeys(hostkeys, host, sysfile, 0); 381 if (userfile != NULL) { 382 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); 383 if (options.strict_modes && 384 (stat(user_hostfile, &st) == 0) && 385 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || 386 (st.st_mode & 022) != 0)) { 387 logit("Authentication refused for %.100s: " 388 "bad owner or modes for %.200s", 389 pw->pw_name, user_hostfile); 390 auth_debug_add("Ignored %.200s: bad ownership or modes", 391 user_hostfile); 392 } else { 393 temporarily_use_uid(pw); 394 load_hostkeys(hostkeys, host, user_hostfile, 0); 395 restore_uid(); 396 } 397 free(user_hostfile); 398 } 399 host_status = check_key_in_hostkeys(hostkeys, key, &found); 400 if (host_status == HOST_REVOKED) 401 error("WARNING: revoked key for %s attempted authentication", 402 host); 403 else if (host_status == HOST_OK) 404 debug_f("key for %s found at %s:%ld", 405 found->host, found->file, found->line); 406 else 407 debug_f("key for host %s not found", host); 408 409 free_hostkeys(hostkeys); 410 411 return host_status; 412 } 413 414 struct passwd * 415 getpwnamallow(struct ssh *ssh, const char *user) 416 { 417 extern login_cap_t *lc; 418 auth_session_t *as; 419 struct passwd *pw; 420 struct connection_info *ci; 421 u_int i; 422 423 ci = get_connection_info(ssh, 1, options.use_dns); 424 ci->user = user; 425 parse_server_match_config(&options, &includes, ci); 426 log_change_level(options.log_level); 427 log_verbose_reset(); 428 for (i = 0; i < options.num_log_verbose; i++) 429 log_verbose_add(options.log_verbose[i]); 430 process_permitopen(ssh, &options); 431 432 pw = getpwnam(user); 433 if (pw == NULL) { 434 logit("Invalid user %.100s from %.100s port %d", 435 user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 436 return (NULL); 437 } 438 if (!allowed_user(ssh, pw)) 439 return (NULL); 440 if ((lc = login_getclass(pw->pw_class)) == NULL) { 441 debug("unable to get login class: %s", user); 442 return (NULL); 443 } 444 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || 445 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { 446 debug("Approval failure for %s", user); 447 pw = NULL; 448 } 449 if (as != NULL) 450 auth_close(as); 451 if (pw != NULL) 452 return (pwcopy(pw)); 453 return (NULL); 454 } 455 456 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ 457 int 458 auth_key_is_revoked(struct sshkey *key) 459 { 460 char *fp = NULL; 461 int r; 462 463 if (options.revoked_keys_file == NULL) 464 return 0; 465 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 466 SSH_FP_DEFAULT)) == NULL) { 467 r = SSH_ERR_ALLOC_FAIL; 468 error_fr(r, "fingerprint key"); 469 goto out; 470 } 471 472 r = sshkey_check_revoked(key, options.revoked_keys_file); 473 switch (r) { 474 case 0: 475 break; /* not revoked */ 476 case SSH_ERR_KEY_REVOKED: 477 error("Authentication key %s %s revoked by file %s", 478 sshkey_type(key), fp, options.revoked_keys_file); 479 goto out; 480 default: 481 error_r(r, "Error checking authentication key %s %s in " 482 "revoked keys file %s", sshkey_type(key), fp, 483 options.revoked_keys_file); 484 goto out; 485 } 486 487 /* Success */ 488 r = 0; 489 490 out: 491 free(fp); 492 return r == 0 ? 0 : 1; 493 } 494 495 void 496 auth_debug_add(const char *fmt,...) 497 { 498 char buf[1024]; 499 va_list args; 500 int r; 501 502 va_start(args, fmt); 503 vsnprintf(buf, sizeof(buf), fmt, args); 504 va_end(args); 505 debug3("%s", buf); 506 if (auth_debug != NULL) 507 if ((r = sshbuf_put_cstring(auth_debug, buf)) != 0) 508 fatal_fr(r, "sshbuf_put_cstring"); 509 } 510 511 void 512 auth_debug_send(struct ssh *ssh) 513 { 514 char *msg; 515 int r; 516 517 if (auth_debug == NULL) 518 return; 519 while (sshbuf_len(auth_debug) != 0) { 520 if ((r = sshbuf_get_cstring(auth_debug, &msg, NULL)) != 0) 521 fatal_fr(r, "sshbuf_get_cstring"); 522 ssh_packet_send_debug(ssh, "%s", msg); 523 free(msg); 524 } 525 } 526 527 void 528 auth_debug_reset(void) 529 { 530 if (auth_debug != NULL) 531 sshbuf_reset(auth_debug); 532 else if ((auth_debug = sshbuf_new()) == NULL) 533 fatal_f("sshbuf_new failed"); 534 } 535 536 struct passwd * 537 fakepw(void) 538 { 539 static int done = 0; 540 static struct passwd fake; 541 const char hashchars[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZ" 542 "abcdefghijklmnopqrstuvwxyz0123456789"; /* from bcrypt.c */ 543 char *cp; 544 545 if (done) 546 return (&fake); 547 548 memset(&fake, 0, sizeof(fake)); 549 fake.pw_name = "NOUSER"; 550 fake.pw_passwd = xstrdup("$2a$10$" 551 "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); 552 for (cp = fake.pw_passwd + 7; *cp != '\0'; cp++) 553 *cp = hashchars[arc4random_uniform(sizeof(hashchars) - 1)]; 554 fake.pw_gecos = "NOUSER"; 555 fake.pw_uid = (uid_t)-1; 556 fake.pw_gid = (gid_t)-1; 557 fake.pw_class = ""; 558 fake.pw_dir = "/nonexist"; 559 fake.pw_shell = "/nonexist"; 560 done = 1; 561 562 return (&fake); 563 } 564 565 /* 566 * Returns the remote DNS hostname as a string. The returned string must not 567 * be freed. NB. this will usually trigger a DNS query the first time it is 568 * called. 569 * This function does additional checks on the hostname to mitigate some 570 * attacks on based on conflation of hostnames and IP addresses. 571 */ 572 573 static char * 574 remote_hostname(struct ssh *ssh) 575 { 576 struct sockaddr_storage from; 577 socklen_t fromlen; 578 struct addrinfo hints, *ai, *aitop; 579 char name[NI_MAXHOST], ntop2[NI_MAXHOST]; 580 const char *ntop = ssh_remote_ipaddr(ssh); 581 582 /* Get IP address of client. */ 583 fromlen = sizeof(from); 584 memset(&from, 0, sizeof(from)); 585 if (getpeername(ssh_packet_get_connection_in(ssh), 586 (struct sockaddr *)&from, &fromlen) == -1) { 587 debug("getpeername failed: %.100s", strerror(errno)); 588 return xstrdup(ntop); 589 } 590 591 debug3("Trying to reverse map address %.100s.", ntop); 592 /* Map the IP address to a host name. */ 593 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), 594 NULL, 0, NI_NAMEREQD) != 0) { 595 /* Host name not found. Use ip address. */ 596 return xstrdup(ntop); 597 } 598 599 /* 600 * if reverse lookup result looks like a numeric hostname, 601 * someone is trying to trick us by PTR record like following: 602 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 603 */ 604 memset(&hints, 0, sizeof(hints)); 605 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 606 hints.ai_flags = AI_NUMERICHOST; 607 if (getaddrinfo(name, NULL, &hints, &ai) == 0) { 608 logit("Nasty PTR record \"%s\" is set up for %s, ignoring", 609 name, ntop); 610 freeaddrinfo(ai); 611 return xstrdup(ntop); 612 } 613 614 /* Names are stored in lowercase. */ 615 lowercase(name); 616 617 /* 618 * Map it back to an IP address and check that the given 619 * address actually is an address of this host. This is 620 * necessary because anyone with access to a name server can 621 * define arbitrary names for an IP address. Mapping from 622 * name to IP address can be trusted better (but can still be 623 * fooled if the intruder has access to the name server of 624 * the domain). 625 */ 626 memset(&hints, 0, sizeof(hints)); 627 hints.ai_family = from.ss_family; 628 hints.ai_socktype = SOCK_STREAM; 629 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { 630 logit("reverse mapping checking getaddrinfo for %.700s " 631 "[%s] failed.", name, ntop); 632 return xstrdup(ntop); 633 } 634 /* Look for the address from the list of addresses. */ 635 for (ai = aitop; ai; ai = ai->ai_next) { 636 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, 637 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && 638 (strcmp(ntop, ntop2) == 0)) 639 break; 640 } 641 freeaddrinfo(aitop); 642 /* If we reached the end of the list, the address was not there. */ 643 if (ai == NULL) { 644 /* Address not found for the host name. */ 645 logit("Address %.100s maps to %.600s, but this does not " 646 "map back to the address.", ntop, name); 647 return xstrdup(ntop); 648 } 649 return xstrdup(name); 650 } 651 652 /* 653 * Return the canonical name of the host in the other side of the current 654 * connection. The host name is cached, so it is efficient to call this 655 * several times. 656 */ 657 658 const char * 659 auth_get_canonical_hostname(struct ssh *ssh, int use_dns) 660 { 661 static char *dnsname; 662 663 if (!use_dns) 664 return ssh_remote_ipaddr(ssh); 665 else if (dnsname != NULL) 666 return dnsname; 667 else { 668 dnsname = remote_hostname(ssh); 669 return dnsname; 670 } 671 } 672 673 /* These functions link key/cert options to the auth framework */ 674 675 /* Log sshauthopt options locally and (optionally) for remote transmission */ 676 void 677 auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote) 678 { 679 int do_env = options.permit_user_env && opts->nenv > 0; 680 int do_permitopen = opts->npermitopen > 0 && 681 (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0; 682 int do_permitlisten = opts->npermitlisten > 0 && 683 (options.allow_tcp_forwarding & FORWARD_REMOTE) != 0; 684 size_t i; 685 char msg[1024], buf[64]; 686 687 snprintf(buf, sizeof(buf), "%d", opts->force_tun_device); 688 /* Try to keep this alphabetically sorted */ 689 snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s", 690 opts->permit_agent_forwarding_flag ? " agent-forwarding" : "", 691 opts->force_command == NULL ? "" : " command", 692 do_env ? " environment" : "", 693 opts->valid_before == 0 ? "" : "expires", 694 opts->no_require_user_presence ? " no-touch-required" : "", 695 do_permitopen ? " permitopen" : "", 696 do_permitlisten ? " permitlisten" : "", 697 opts->permit_port_forwarding_flag ? " port-forwarding" : "", 698 opts->cert_principals == NULL ? "" : " principals", 699 opts->permit_pty_flag ? " pty" : "", 700 opts->require_verify ? " uv" : "", 701 opts->force_tun_device == -1 ? "" : " tun=", 702 opts->force_tun_device == -1 ? "" : buf, 703 opts->permit_user_rc ? " user-rc" : "", 704 opts->permit_x11_forwarding_flag ? " x11-forwarding" : ""); 705 706 debug("%s: %s", loc, msg); 707 if (do_remote) 708 auth_debug_add("%s: %s", loc, msg); 709 710 if (options.permit_user_env) { 711 for (i = 0; i < opts->nenv; i++) { 712 debug("%s: environment: %s", loc, opts->env[i]); 713 if (do_remote) { 714 auth_debug_add("%s: environment: %s", 715 loc, opts->env[i]); 716 } 717 } 718 } 719 720 /* Go into a little more details for the local logs. */ 721 if (opts->valid_before != 0) { 722 format_absolute_time(opts->valid_before, buf, sizeof(buf)); 723 debug("%s: expires at %s", loc, buf); 724 } 725 if (opts->cert_principals != NULL) { 726 debug("%s: authorized principals: \"%s\"", 727 loc, opts->cert_principals); 728 } 729 if (opts->force_command != NULL) 730 debug("%s: forced command: \"%s\"", loc, opts->force_command); 731 if (do_permitopen) { 732 for (i = 0; i < opts->npermitopen; i++) { 733 debug("%s: permitted open: %s", 734 loc, opts->permitopen[i]); 735 } 736 } 737 if (do_permitlisten) { 738 for (i = 0; i < opts->npermitlisten; i++) { 739 debug("%s: permitted listen: %s", 740 loc, opts->permitlisten[i]); 741 } 742 } 743 } 744 745 /* Activate a new set of key/cert options; merging with what is there. */ 746 int 747 auth_activate_options(struct ssh *ssh, struct sshauthopt *opts) 748 { 749 struct sshauthopt *old = auth_opts; 750 const char *emsg = NULL; 751 752 debug_f("setting new authentication options"); 753 if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) { 754 error("Inconsistent authentication options: %s", emsg); 755 return -1; 756 } 757 return 0; 758 } 759 760 /* Disable forwarding, etc for the session */ 761 void 762 auth_restrict_session(struct ssh *ssh) 763 { 764 struct sshauthopt *restricted; 765 766 debug_f("restricting session"); 767 768 /* A blank sshauthopt defaults to permitting nothing */ 769 if ((restricted = sshauthopt_new()) == NULL) 770 fatal_f("sshauthopt_new failed"); 771 restricted->permit_pty_flag = 1; 772 restricted->restricted = 1; 773 774 if (auth_activate_options(ssh, restricted) != 0) 775 fatal_f("failed to restrict session"); 776 sshauthopt_free(restricted); 777 } 778