1 /* $OpenBSD: auth.c,v 1.159 2022/12/09 00:17:40 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 "compat.h" 66 #include "channels.h" 67 68 /* import */ 69 extern ServerOptions options; 70 extern struct include_list includes; 71 extern int use_privsep; 72 extern struct sshauthopt *auth_opts; 73 74 /* Debugging messages */ 75 static struct sshbuf *auth_debug; 76 77 /* 78 * Check if the user is allowed to log in via ssh. If user is listed 79 * in DenyUsers or one of user's groups is listed in DenyGroups, false 80 * will be returned. If AllowUsers isn't empty and user isn't listed 81 * there, or if AllowGroups isn't empty and one of user's groups isn't 82 * listed there, false will be returned. 83 * If the user's shell is not executable, false will be returned. 84 * Otherwise true is returned. 85 */ 86 int 87 allowed_user(struct ssh *ssh, struct passwd * pw) 88 { 89 struct stat st; 90 const char *hostname = NULL, *ipaddr = NULL; 91 int r; 92 u_int i; 93 94 /* Shouldn't be called if pw is NULL, but better safe than sorry... */ 95 if (!pw || !pw->pw_name) 96 return 0; 97 98 /* 99 * Deny if shell does not exist or is not executable unless we 100 * are chrooting. 101 */ 102 if (options.chroot_directory == NULL || 103 strcasecmp(options.chroot_directory, "none") == 0) { 104 char *shell = xstrdup((pw->pw_shell[0] == '\0') ? 105 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ 106 107 if (stat(shell, &st) == -1) { 108 logit("User %.100s not allowed because shell %.100s " 109 "does not exist", pw->pw_name, shell); 110 free(shell); 111 return 0; 112 } 113 if (S_ISREG(st.st_mode) == 0 || 114 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { 115 logit("User %.100s not allowed because shell %.100s " 116 "is not executable", pw->pw_name, shell); 117 free(shell); 118 return 0; 119 } 120 free(shell); 121 } 122 123 if (options.num_deny_users > 0 || options.num_allow_users > 0 || 124 options.num_deny_groups > 0 || options.num_allow_groups > 0) { 125 hostname = auth_get_canonical_hostname(ssh, options.use_dns); 126 ipaddr = ssh_remote_ipaddr(ssh); 127 } 128 129 /* Return false if user is listed in DenyUsers */ 130 if (options.num_deny_users > 0) { 131 for (i = 0; i < options.num_deny_users; i++) { 132 r = match_user(pw->pw_name, hostname, ipaddr, 133 options.deny_users[i]); 134 if (r < 0) { 135 fatal("Invalid DenyUsers pattern \"%.100s\"", 136 options.deny_users[i]); 137 } else if (r != 0) { 138 logit("User %.100s from %.100s not allowed " 139 "because listed in DenyUsers", 140 pw->pw_name, hostname); 141 return 0; 142 } 143 } 144 } 145 /* Return false if AllowUsers isn't empty and user isn't listed there */ 146 if (options.num_allow_users > 0) { 147 for (i = 0; i < options.num_allow_users; i++) { 148 r = match_user(pw->pw_name, hostname, ipaddr, 149 options.allow_users[i]); 150 if (r < 0) { 151 fatal("Invalid AllowUsers pattern \"%.100s\"", 152 options.allow_users[i]); 153 } else if (r == 1) 154 break; 155 } 156 /* i < options.num_allow_users iff we break for loop */ 157 if (i >= options.num_allow_users) { 158 logit("User %.100s from %.100s not allowed because " 159 "not listed in AllowUsers", pw->pw_name, hostname); 160 return 0; 161 } 162 } 163 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { 164 /* Get the user's group access list (primary and supplementary) */ 165 if (ga_init(pw->pw_name, pw->pw_gid) == 0) { 166 logit("User %.100s from %.100s not allowed because " 167 "not in any group", pw->pw_name, hostname); 168 return 0; 169 } 170 171 /* Return false if one of user's groups is listed in DenyGroups */ 172 if (options.num_deny_groups > 0) 173 if (ga_match(options.deny_groups, 174 options.num_deny_groups)) { 175 ga_free(); 176 logit("User %.100s from %.100s not allowed " 177 "because a group is listed in DenyGroups", 178 pw->pw_name, hostname); 179 return 0; 180 } 181 /* 182 * Return false if AllowGroups isn't empty and one of user's groups 183 * isn't listed there 184 */ 185 if (options.num_allow_groups > 0) 186 if (!ga_match(options.allow_groups, 187 options.num_allow_groups)) { 188 ga_free(); 189 logit("User %.100s from %.100s not allowed " 190 "because none of user's groups are listed " 191 "in AllowGroups", pw->pw_name, hostname); 192 return 0; 193 } 194 ga_free(); 195 } 196 /* We found no reason not to let this user try to log on... */ 197 return 1; 198 } 199 200 /* 201 * Formats any key left in authctxt->auth_method_key for inclusion in 202 * auth_log()'s message. Also includes authxtct->auth_method_info if present. 203 */ 204 static char * 205 format_method_key(Authctxt *authctxt) 206 { 207 const struct sshkey *key = authctxt->auth_method_key; 208 const char *methinfo = authctxt->auth_method_info; 209 char *fp, *cafp, *ret = NULL; 210 211 if (key == NULL) 212 return NULL; 213 214 if (sshkey_is_cert(key)) { 215 fp = sshkey_fingerprint(key, 216 options.fingerprint_hash, SSH_FP_DEFAULT); 217 cafp = sshkey_fingerprint(key->cert->signature_key, 218 options.fingerprint_hash, SSH_FP_DEFAULT); 219 xasprintf(&ret, "%s %s ID %s (serial %llu) CA %s %s%s%s", 220 sshkey_type(key), fp == NULL ? "(null)" : fp, 221 key->cert->key_id, 222 (unsigned long long)key->cert->serial, 223 sshkey_type(key->cert->signature_key), 224 cafp == NULL ? "(null)" : cafp, 225 methinfo == NULL ? "" : ", ", 226 methinfo == NULL ? "" : methinfo); 227 free(fp); 228 free(cafp); 229 } else { 230 fp = sshkey_fingerprint(key, options.fingerprint_hash, 231 SSH_FP_DEFAULT); 232 xasprintf(&ret, "%s %s%s%s", sshkey_type(key), 233 fp == NULL ? "(null)" : fp, 234 methinfo == NULL ? "" : ", ", 235 methinfo == NULL ? "" : methinfo); 236 free(fp); 237 } 238 return ret; 239 } 240 241 void 242 auth_log(struct ssh *ssh, int authenticated, int partial, 243 const char *method, const char *submethod) 244 { 245 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 246 int level = SYSLOG_LEVEL_VERBOSE; 247 const char *authmsg; 248 char *extra = NULL; 249 250 if (use_privsep && !mm_is_monitor() && !authctxt->postponed) 251 return; 252 253 /* Raise logging level */ 254 if (authenticated == 1 || 255 !authctxt->valid || 256 authctxt->failures >= options.max_authtries / 2 || 257 strcmp(method, "password") == 0) 258 level = SYSLOG_LEVEL_INFO; 259 260 if (authctxt->postponed) 261 authmsg = "Postponed"; 262 else if (partial) 263 authmsg = "Partial"; 264 else 265 authmsg = authenticated ? "Accepted" : "Failed"; 266 267 if ((extra = format_method_key(authctxt)) == NULL) { 268 if (authctxt->auth_method_info != NULL) 269 extra = xstrdup(authctxt->auth_method_info); 270 } 271 272 do_log2(level, "%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s", 273 authmsg, 274 method, 275 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, 276 authctxt->valid ? "" : "invalid user ", 277 authctxt->user, 278 ssh_remote_ipaddr(ssh), 279 ssh_remote_port(ssh), 280 extra != NULL ? ": " : "", 281 extra != NULL ? extra : ""); 282 283 free(extra); 284 } 285 286 void 287 auth_maxtries_exceeded(struct ssh *ssh) 288 { 289 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 290 291 error("maximum authentication attempts exceeded for " 292 "%s%.100s from %.200s port %d ssh2", 293 authctxt->valid ? "" : "invalid user ", 294 authctxt->user, 295 ssh_remote_ipaddr(ssh), 296 ssh_remote_port(ssh)); 297 ssh_packet_disconnect(ssh, "Too many authentication failures"); 298 /* NOTREACHED */ 299 } 300 301 /* 302 * Check whether root logins are disallowed. 303 */ 304 int 305 auth_root_allowed(struct ssh *ssh, const char *method) 306 { 307 switch (options.permit_root_login) { 308 case PERMIT_YES: 309 return 1; 310 case PERMIT_NO_PASSWD: 311 if (strcmp(method, "publickey") == 0 || 312 strcmp(method, "hostbased") == 0 || 313 strcmp(method, "gssapi-with-mic") == 0) 314 return 1; 315 break; 316 case PERMIT_FORCED_ONLY: 317 if (auth_opts->force_command != NULL) { 318 logit("Root login accepted for forced command."); 319 return 1; 320 } 321 break; 322 } 323 logit("ROOT LOGIN REFUSED FROM %.200s port %d", 324 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 325 return 0; 326 } 327 328 329 /* 330 * Given a template and a passwd structure, build a filename 331 * by substituting % tokenised options. Currently, %% becomes '%', 332 * %h becomes the home directory and %u the username. 333 * 334 * This returns a buffer allocated by xmalloc. 335 */ 336 char * 337 expand_authorized_keys(const char *filename, struct passwd *pw) 338 { 339 char *file, uidstr[32], ret[PATH_MAX]; 340 int i; 341 342 snprintf(uidstr, sizeof(uidstr), "%llu", 343 (unsigned long long)pw->pw_uid); 344 file = percent_expand(filename, "h", pw->pw_dir, 345 "u", pw->pw_name, "U", uidstr, (char *)NULL); 346 347 /* 348 * Ensure that filename starts anchored. If not, be backward 349 * compatible and prepend the '%h/' 350 */ 351 if (path_absolute(file)) 352 return (file); 353 354 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); 355 if (i < 0 || (size_t)i >= sizeof(ret)) 356 fatal("expand_authorized_keys: path too long"); 357 free(file); 358 return (xstrdup(ret)); 359 } 360 361 char * 362 authorized_principals_file(struct passwd *pw) 363 { 364 if (options.authorized_principals_file == NULL) 365 return NULL; 366 return expand_authorized_keys(options.authorized_principals_file, pw); 367 } 368 369 /* return ok if key exists in sysfile or userfile */ 370 HostStatus 371 check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host, 372 const char *sysfile, const char *userfile) 373 { 374 char *user_hostfile; 375 struct stat st; 376 HostStatus host_status; 377 struct hostkeys *hostkeys; 378 const struct hostkey_entry *found; 379 380 hostkeys = init_hostkeys(); 381 load_hostkeys(hostkeys, host, sysfile, 0); 382 if (userfile != NULL) { 383 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); 384 if (options.strict_modes && 385 (stat(user_hostfile, &st) == 0) && 386 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || 387 (st.st_mode & 022) != 0)) { 388 logit("Authentication refused for %.100s: " 389 "bad owner or modes for %.200s", 390 pw->pw_name, user_hostfile); 391 auth_debug_add("Ignored %.200s: bad ownership or modes", 392 user_hostfile); 393 } else { 394 temporarily_use_uid(pw); 395 load_hostkeys(hostkeys, host, user_hostfile, 0); 396 restore_uid(); 397 } 398 free(user_hostfile); 399 } 400 host_status = check_key_in_hostkeys(hostkeys, key, &found); 401 if (host_status == HOST_REVOKED) 402 error("WARNING: revoked key for %s attempted authentication", 403 host); 404 else if (host_status == HOST_OK) 405 debug_f("key for %s found at %s:%ld", 406 found->host, found->file, found->line); 407 else 408 debug_f("key for host %s not found", host); 409 410 free_hostkeys(hostkeys); 411 412 return host_status; 413 } 414 415 struct passwd * 416 getpwnamallow(struct ssh *ssh, const char *user) 417 { 418 extern login_cap_t *lc; 419 auth_session_t *as; 420 struct passwd *pw; 421 struct connection_info *ci; 422 u_int i; 423 424 ci = get_connection_info(ssh, 1, options.use_dns); 425 ci->user = user; 426 parse_server_match_config(&options, &includes, ci); 427 log_change_level(options.log_level); 428 log_verbose_reset(); 429 for (i = 0; i < options.num_log_verbose; i++) 430 log_verbose_add(options.log_verbose[i]); 431 process_permitopen(ssh, &options); 432 433 pw = getpwnam(user); 434 if (pw == NULL) { 435 logit("Invalid user %.100s from %.100s port %d", 436 user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 437 return (NULL); 438 } 439 if (!allowed_user(ssh, pw)) 440 return (NULL); 441 if ((lc = login_getclass(pw->pw_class)) == NULL) { 442 debug("unable to get login class: %s", user); 443 return (NULL); 444 } 445 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || 446 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { 447 debug("Approval failure for %s", user); 448 pw = NULL; 449 } 450 if (as != NULL) 451 auth_close(as); 452 if (pw != NULL) 453 return (pwcopy(pw)); 454 return (NULL); 455 } 456 457 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ 458 int 459 auth_key_is_revoked(struct sshkey *key) 460 { 461 char *fp = NULL; 462 int r; 463 464 if (options.revoked_keys_file == NULL) 465 return 0; 466 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 467 SSH_FP_DEFAULT)) == NULL) { 468 r = SSH_ERR_ALLOC_FAIL; 469 error_fr(r, "fingerprint key"); 470 goto out; 471 } 472 473 r = sshkey_check_revoked(key, options.revoked_keys_file); 474 switch (r) { 475 case 0: 476 break; /* not revoked */ 477 case SSH_ERR_KEY_REVOKED: 478 error("Authentication key %s %s revoked by file %s", 479 sshkey_type(key), fp, options.revoked_keys_file); 480 goto out; 481 default: 482 error_r(r, "Error checking authentication key %s %s in " 483 "revoked keys file %s", sshkey_type(key), fp, 484 options.revoked_keys_file); 485 goto out; 486 } 487 488 /* Success */ 489 r = 0; 490 491 out: 492 free(fp); 493 return r == 0 ? 0 : 1; 494 } 495 496 void 497 auth_debug_add(const char *fmt,...) 498 { 499 char buf[1024]; 500 va_list args; 501 int r; 502 503 va_start(args, fmt); 504 vsnprintf(buf, sizeof(buf), fmt, args); 505 va_end(args); 506 debug3("%s", buf); 507 if (auth_debug != NULL) 508 if ((r = sshbuf_put_cstring(auth_debug, buf)) != 0) 509 fatal_fr(r, "sshbuf_put_cstring"); 510 } 511 512 void 513 auth_debug_send(struct ssh *ssh) 514 { 515 char *msg; 516 int r; 517 518 if (auth_debug == NULL) 519 return; 520 while (sshbuf_len(auth_debug) != 0) { 521 if ((r = sshbuf_get_cstring(auth_debug, &msg, NULL)) != 0) 522 fatal_fr(r, "sshbuf_get_cstring"); 523 ssh_packet_send_debug(ssh, "%s", msg); 524 free(msg); 525 } 526 } 527 528 void 529 auth_debug_reset(void) 530 { 531 if (auth_debug != NULL) 532 sshbuf_reset(auth_debug); 533 else if ((auth_debug = sshbuf_new()) == NULL) 534 fatal_f("sshbuf_new failed"); 535 } 536 537 struct passwd * 538 fakepw(void) 539 { 540 static int done = 0; 541 static struct passwd fake; 542 const char hashchars[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZ" 543 "abcdefghijklmnopqrstuvwxyz0123456789"; /* from bcrypt.c */ 544 char *cp; 545 546 if (done) 547 return (&fake); 548 549 memset(&fake, 0, sizeof(fake)); 550 fake.pw_name = "NOUSER"; 551 fake.pw_passwd = xstrdup("$2a$10$" 552 "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); 553 for (cp = fake.pw_passwd + 7; *cp != '\0'; cp++) 554 *cp = hashchars[arc4random_uniform(sizeof(hashchars) - 1)]; 555 fake.pw_gecos = "NOUSER"; 556 fake.pw_uid = (uid_t)-1; 557 fake.pw_gid = (gid_t)-1; 558 fake.pw_class = ""; 559 fake.pw_dir = "/nonexist"; 560 fake.pw_shell = "/nonexist"; 561 done = 1; 562 563 return (&fake); 564 } 565 566 /* 567 * Returns the remote DNS hostname as a string. The returned string must not 568 * be freed. NB. this will usually trigger a DNS query the first time it is 569 * called. 570 * This function does additional checks on the hostname to mitigate some 571 * attacks on based on conflation of hostnames and IP addresses. 572 */ 573 574 static char * 575 remote_hostname(struct ssh *ssh) 576 { 577 struct sockaddr_storage from; 578 socklen_t fromlen; 579 struct addrinfo hints, *ai, *aitop; 580 char name[NI_MAXHOST], ntop2[NI_MAXHOST]; 581 const char *ntop = ssh_remote_ipaddr(ssh); 582 583 /* Get IP address of client. */ 584 fromlen = sizeof(from); 585 memset(&from, 0, sizeof(from)); 586 if (getpeername(ssh_packet_get_connection_in(ssh), 587 (struct sockaddr *)&from, &fromlen) == -1) { 588 debug("getpeername failed: %.100s", strerror(errno)); 589 return xstrdup(ntop); 590 } 591 592 debug3("Trying to reverse map address %.100s.", ntop); 593 /* Map the IP address to a host name. */ 594 if (getnameinfo((struct sockaddr *)&from, fromlen, name, sizeof(name), 595 NULL, 0, NI_NAMEREQD) != 0) { 596 /* Host name not found. Use ip address. */ 597 return xstrdup(ntop); 598 } 599 600 /* 601 * if reverse lookup result looks like a numeric hostname, 602 * someone is trying to trick us by PTR record like following: 603 * 1.1.1.10.in-addr.arpa. IN PTR 2.3.4.5 604 */ 605 memset(&hints, 0, sizeof(hints)); 606 hints.ai_socktype = SOCK_DGRAM; /*dummy*/ 607 hints.ai_flags = AI_NUMERICHOST; 608 if (getaddrinfo(name, NULL, &hints, &ai) == 0) { 609 logit("Nasty PTR record \"%s\" is set up for %s, ignoring", 610 name, ntop); 611 freeaddrinfo(ai); 612 return xstrdup(ntop); 613 } 614 615 /* Names are stored in lowercase. */ 616 lowercase(name); 617 618 /* 619 * Map it back to an IP address and check that the given 620 * address actually is an address of this host. This is 621 * necessary because anyone with access to a name server can 622 * define arbitrary names for an IP address. Mapping from 623 * name to IP address can be trusted better (but can still be 624 * fooled if the intruder has access to the name server of 625 * the domain). 626 */ 627 memset(&hints, 0, sizeof(hints)); 628 hints.ai_family = from.ss_family; 629 hints.ai_socktype = SOCK_STREAM; 630 if (getaddrinfo(name, NULL, &hints, &aitop) != 0) { 631 logit("reverse mapping checking getaddrinfo for %.700s " 632 "[%s] failed.", name, ntop); 633 return xstrdup(ntop); 634 } 635 /* Look for the address from the list of addresses. */ 636 for (ai = aitop; ai; ai = ai->ai_next) { 637 if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop2, 638 sizeof(ntop2), NULL, 0, NI_NUMERICHOST) == 0 && 639 (strcmp(ntop, ntop2) == 0)) 640 break; 641 } 642 freeaddrinfo(aitop); 643 /* If we reached the end of the list, the address was not there. */ 644 if (ai == NULL) { 645 /* Address not found for the host name. */ 646 logit("Address %.100s maps to %.600s, but this does not " 647 "map back to the address.", ntop, name); 648 return xstrdup(ntop); 649 } 650 return xstrdup(name); 651 } 652 653 /* 654 * Return the canonical name of the host in the other side of the current 655 * connection. The host name is cached, so it is efficient to call this 656 * several times. 657 */ 658 659 const char * 660 auth_get_canonical_hostname(struct ssh *ssh, int use_dns) 661 { 662 static char *dnsname; 663 664 if (!use_dns) 665 return ssh_remote_ipaddr(ssh); 666 else if (dnsname != NULL) 667 return dnsname; 668 else { 669 dnsname = remote_hostname(ssh); 670 return dnsname; 671 } 672 } 673 674 /* These functions link key/cert options to the auth framework */ 675 676 /* Log sshauthopt options locally and (optionally) for remote transmission */ 677 void 678 auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote) 679 { 680 int do_env = options.permit_user_env && opts->nenv > 0; 681 int do_permitopen = opts->npermitopen > 0 && 682 (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0; 683 int do_permitlisten = opts->npermitlisten > 0 && 684 (options.allow_tcp_forwarding & FORWARD_REMOTE) != 0; 685 size_t i; 686 char msg[1024], buf[64]; 687 688 snprintf(buf, sizeof(buf), "%d", opts->force_tun_device); 689 /* Try to keep this alphabetically sorted */ 690 snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s", 691 opts->permit_agent_forwarding_flag ? " agent-forwarding" : "", 692 opts->force_command == NULL ? "" : " command", 693 do_env ? " environment" : "", 694 opts->valid_before == 0 ? "" : "expires", 695 opts->no_require_user_presence ? " no-touch-required" : "", 696 do_permitopen ? " permitopen" : "", 697 do_permitlisten ? " permitlisten" : "", 698 opts->permit_port_forwarding_flag ? " port-forwarding" : "", 699 opts->cert_principals == NULL ? "" : " principals", 700 opts->permit_pty_flag ? " pty" : "", 701 opts->require_verify ? " uv" : "", 702 opts->force_tun_device == -1 ? "" : " tun=", 703 opts->force_tun_device == -1 ? "" : buf, 704 opts->permit_user_rc ? " user-rc" : "", 705 opts->permit_x11_forwarding_flag ? " x11-forwarding" : ""); 706 707 debug("%s: %s", loc, msg); 708 if (do_remote) 709 auth_debug_add("%s: %s", loc, msg); 710 711 if (options.permit_user_env) { 712 for (i = 0; i < opts->nenv; i++) { 713 debug("%s: environment: %s", loc, opts->env[i]); 714 if (do_remote) { 715 auth_debug_add("%s: environment: %s", 716 loc, opts->env[i]); 717 } 718 } 719 } 720 721 /* Go into a little more details for the local logs. */ 722 if (opts->valid_before != 0) { 723 format_absolute_time(opts->valid_before, buf, sizeof(buf)); 724 debug("%s: expires at %s", loc, buf); 725 } 726 if (opts->cert_principals != NULL) { 727 debug("%s: authorized principals: \"%s\"", 728 loc, opts->cert_principals); 729 } 730 if (opts->force_command != NULL) 731 debug("%s: forced command: \"%s\"", loc, opts->force_command); 732 if (do_permitopen) { 733 for (i = 0; i < opts->npermitopen; i++) { 734 debug("%s: permitted open: %s", 735 loc, opts->permitopen[i]); 736 } 737 } 738 if (do_permitlisten) { 739 for (i = 0; i < opts->npermitlisten; i++) { 740 debug("%s: permitted listen: %s", 741 loc, opts->permitlisten[i]); 742 } 743 } 744 } 745 746 /* Activate a new set of key/cert options; merging with what is there. */ 747 int 748 auth_activate_options(struct ssh *ssh, struct sshauthopt *opts) 749 { 750 struct sshauthopt *old = auth_opts; 751 const char *emsg = NULL; 752 753 debug_f("setting new authentication options"); 754 if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) { 755 error("Inconsistent authentication options: %s", emsg); 756 return -1; 757 } 758 return 0; 759 } 760 761 /* Disable forwarding, etc for the session */ 762 void 763 auth_restrict_session(struct ssh *ssh) 764 { 765 struct sshauthopt *restricted; 766 767 debug_f("restricting session"); 768 769 /* A blank sshauthopt defaults to permitting nothing */ 770 if ((restricted = sshauthopt_new()) == NULL) 771 fatal_f("sshauthopt_new failed"); 772 restricted->permit_pty_flag = 1; 773 restricted->restricted = 1; 774 775 if (auth_activate_options(ssh, restricted) != 0) 776 fatal_f("failed to restrict session"); 777 sshauthopt_free(restricted); 778 } 779