1 /* $OpenBSD: auth.c,v 1.161 2024/05/17 00:30:23 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 <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 struct sshauthopt *auth_opts; 71 72 /* Debugging messages */ 73 static struct sshbuf *auth_debug; 74 75 /* 76 * Check if the user is allowed to log in via ssh. If user is listed 77 * in DenyUsers or one of user's groups is listed in DenyGroups, false 78 * will be returned. If AllowUsers isn't empty and user isn't listed 79 * there, or if AllowGroups isn't empty and one of user's groups isn't 80 * listed there, false will be returned. 81 * If the user's shell is not executable, false will be returned. 82 * Otherwise true is returned. 83 */ 84 int 85 allowed_user(struct ssh *ssh, struct passwd * pw) 86 { 87 struct stat st; 88 const char *hostname = NULL, *ipaddr = NULL; 89 int r; 90 u_int i; 91 92 /* Shouldn't be called if pw is NULL, but better safe than sorry... */ 93 if (!pw || !pw->pw_name) 94 return 0; 95 96 /* 97 * Deny if shell does not exist or is not executable unless we 98 * are chrooting. 99 */ 100 if (options.chroot_directory == NULL || 101 strcasecmp(options.chroot_directory, "none") == 0) { 102 char *shell = xstrdup((pw->pw_shell[0] == '\0') ? 103 _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */ 104 105 if (stat(shell, &st) == -1) { 106 logit("User %.100s not allowed because shell %.100s " 107 "does not exist", pw->pw_name, shell); 108 free(shell); 109 return 0; 110 } 111 if (S_ISREG(st.st_mode) == 0 || 112 (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) { 113 logit("User %.100s not allowed because shell %.100s " 114 "is not executable", pw->pw_name, shell); 115 free(shell); 116 return 0; 117 } 118 free(shell); 119 } 120 121 if (options.num_deny_users > 0 || options.num_allow_users > 0 || 122 options.num_deny_groups > 0 || options.num_allow_groups > 0) { 123 hostname = auth_get_canonical_hostname(ssh, options.use_dns); 124 ipaddr = ssh_remote_ipaddr(ssh); 125 } 126 127 /* Return false if user is listed in DenyUsers */ 128 if (options.num_deny_users > 0) { 129 for (i = 0; i < options.num_deny_users; i++) { 130 r = match_user(pw->pw_name, hostname, ipaddr, 131 options.deny_users[i]); 132 if (r < 0) { 133 fatal("Invalid DenyUsers pattern \"%.100s\"", 134 options.deny_users[i]); 135 } else if (r != 0) { 136 logit("User %.100s from %.100s not allowed " 137 "because listed in DenyUsers", 138 pw->pw_name, hostname); 139 return 0; 140 } 141 } 142 } 143 /* Return false if AllowUsers isn't empty and user isn't listed there */ 144 if (options.num_allow_users > 0) { 145 for (i = 0; i < options.num_allow_users; i++) { 146 r = match_user(pw->pw_name, hostname, ipaddr, 147 options.allow_users[i]); 148 if (r < 0) { 149 fatal("Invalid AllowUsers pattern \"%.100s\"", 150 options.allow_users[i]); 151 } else if (r == 1) 152 break; 153 } 154 /* i < options.num_allow_users iff we break for loop */ 155 if (i >= options.num_allow_users) { 156 logit("User %.100s from %.100s not allowed because " 157 "not listed in AllowUsers", pw->pw_name, hostname); 158 return 0; 159 } 160 } 161 if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { 162 /* Get the user's group access list (primary and supplementary) */ 163 if (ga_init(pw->pw_name, pw->pw_gid) == 0) { 164 logit("User %.100s from %.100s not allowed because " 165 "not in any group", pw->pw_name, hostname); 166 return 0; 167 } 168 169 /* Return false if one of user's groups is listed in DenyGroups */ 170 if (options.num_deny_groups > 0) 171 if (ga_match(options.deny_groups, 172 options.num_deny_groups)) { 173 ga_free(); 174 logit("User %.100s from %.100s not allowed " 175 "because a group is listed in DenyGroups", 176 pw->pw_name, hostname); 177 return 0; 178 } 179 /* 180 * Return false if AllowGroups isn't empty and one of user's groups 181 * isn't listed there 182 */ 183 if (options.num_allow_groups > 0) 184 if (!ga_match(options.allow_groups, 185 options.num_allow_groups)) { 186 ga_free(); 187 logit("User %.100s from %.100s not allowed " 188 "because none of user's groups are listed " 189 "in AllowGroups", pw->pw_name, hostname); 190 return 0; 191 } 192 ga_free(); 193 } 194 /* We found no reason not to let this user try to log on... */ 195 return 1; 196 } 197 198 /* 199 * Formats any key left in authctxt->auth_method_key for inclusion in 200 * auth_log()'s message. Also includes authxtct->auth_method_info if present. 201 */ 202 static char * 203 format_method_key(Authctxt *authctxt) 204 { 205 const struct sshkey *key = authctxt->auth_method_key; 206 const char *methinfo = authctxt->auth_method_info; 207 char *fp, *cafp, *ret = NULL; 208 209 if (key == NULL) 210 return NULL; 211 212 if (sshkey_is_cert(key)) { 213 fp = sshkey_fingerprint(key, 214 options.fingerprint_hash, SSH_FP_DEFAULT); 215 cafp = sshkey_fingerprint(key->cert->signature_key, 216 options.fingerprint_hash, SSH_FP_DEFAULT); 217 xasprintf(&ret, "%s %s ID %s (serial %llu) CA %s %s%s%s", 218 sshkey_type(key), fp == NULL ? "(null)" : fp, 219 key->cert->key_id, 220 (unsigned long long)key->cert->serial, 221 sshkey_type(key->cert->signature_key), 222 cafp == NULL ? "(null)" : cafp, 223 methinfo == NULL ? "" : ", ", 224 methinfo == NULL ? "" : methinfo); 225 free(fp); 226 free(cafp); 227 } else { 228 fp = sshkey_fingerprint(key, options.fingerprint_hash, 229 SSH_FP_DEFAULT); 230 xasprintf(&ret, "%s %s%s%s", sshkey_type(key), 231 fp == NULL ? "(null)" : fp, 232 methinfo == NULL ? "" : ", ", 233 methinfo == NULL ? "" : methinfo); 234 free(fp); 235 } 236 return ret; 237 } 238 239 void 240 auth_log(struct ssh *ssh, int authenticated, int partial, 241 const char *method, const char *submethod) 242 { 243 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 244 int level = SYSLOG_LEVEL_VERBOSE; 245 const char *authmsg; 246 char *extra = NULL; 247 248 if (!mm_is_monitor() && !authctxt->postponed) 249 return; 250 251 /* Raise logging level */ 252 if (authenticated == 1 || 253 !authctxt->valid || 254 authctxt->failures >= options.max_authtries / 2 || 255 strcmp(method, "password") == 0) 256 level = SYSLOG_LEVEL_INFO; 257 258 if (authctxt->postponed) 259 authmsg = "Postponed"; 260 else if (partial) 261 authmsg = "Partial"; 262 else 263 authmsg = authenticated ? "Accepted" : "Failed"; 264 265 if ((extra = format_method_key(authctxt)) == NULL) { 266 if (authctxt->auth_method_info != NULL) 267 extra = xstrdup(authctxt->auth_method_info); 268 } 269 270 do_log2(level, "%s %s%s%s for %s%.100s from %.200s port %d ssh2%s%s", 271 authmsg, 272 method, 273 submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod, 274 authctxt->valid ? "" : "invalid user ", 275 authctxt->user, 276 ssh_remote_ipaddr(ssh), 277 ssh_remote_port(ssh), 278 extra != NULL ? ": " : "", 279 extra != NULL ? extra : ""); 280 281 free(extra); 282 } 283 284 void 285 auth_maxtries_exceeded(struct ssh *ssh) 286 { 287 Authctxt *authctxt = (Authctxt *)ssh->authctxt; 288 289 error("maximum authentication attempts exceeded for " 290 "%s%.100s from %.200s port %d ssh2", 291 authctxt->valid ? "" : "invalid user ", 292 authctxt->user, 293 ssh_remote_ipaddr(ssh), 294 ssh_remote_port(ssh)); 295 ssh_packet_disconnect(ssh, "Too many authentication failures"); 296 /* NOTREACHED */ 297 } 298 299 /* 300 * Check whether root logins are disallowed. 301 */ 302 int 303 auth_root_allowed(struct ssh *ssh, const char *method) 304 { 305 switch (options.permit_root_login) { 306 case PERMIT_YES: 307 return 1; 308 case PERMIT_NO_PASSWD: 309 if (strcmp(method, "publickey") == 0 || 310 strcmp(method, "hostbased") == 0 || 311 strcmp(method, "gssapi-with-mic") == 0) 312 return 1; 313 break; 314 case PERMIT_FORCED_ONLY: 315 if (auth_opts->force_command != NULL) { 316 logit("Root login accepted for forced command."); 317 return 1; 318 } 319 break; 320 } 321 logit("ROOT LOGIN REFUSED FROM %.200s port %d", 322 ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 323 return 0; 324 } 325 326 327 /* 328 * Given a template and a passwd structure, build a filename 329 * by substituting % tokenised options. Currently, %% becomes '%', 330 * %h becomes the home directory and %u the username. 331 * 332 * This returns a buffer allocated by xmalloc. 333 */ 334 char * 335 expand_authorized_keys(const char *filename, struct passwd *pw) 336 { 337 char *file, uidstr[32], ret[PATH_MAX]; 338 int i; 339 340 snprintf(uidstr, sizeof(uidstr), "%llu", 341 (unsigned long long)pw->pw_uid); 342 file = percent_expand(filename, "h", pw->pw_dir, 343 "u", pw->pw_name, "U", uidstr, (char *)NULL); 344 345 /* 346 * Ensure that filename starts anchored. If not, be backward 347 * compatible and prepend the '%h/' 348 */ 349 if (path_absolute(file)) 350 return (file); 351 352 i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file); 353 if (i < 0 || (size_t)i >= sizeof(ret)) 354 fatal("expand_authorized_keys: path too long"); 355 free(file); 356 return (xstrdup(ret)); 357 } 358 359 char * 360 authorized_principals_file(struct passwd *pw) 361 { 362 if (options.authorized_principals_file == NULL) 363 return NULL; 364 return expand_authorized_keys(options.authorized_principals_file, pw); 365 } 366 367 /* return ok if key exists in sysfile or userfile */ 368 HostStatus 369 check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host, 370 const char *sysfile, const char *userfile) 371 { 372 char *user_hostfile; 373 struct stat st; 374 HostStatus host_status; 375 struct hostkeys *hostkeys; 376 const struct hostkey_entry *found; 377 378 hostkeys = init_hostkeys(); 379 load_hostkeys(hostkeys, host, sysfile, 0); 380 if (userfile != NULL) { 381 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); 382 if (options.strict_modes && 383 (stat(user_hostfile, &st) == 0) && 384 ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || 385 (st.st_mode & 022) != 0)) { 386 logit("Authentication refused for %.100s: " 387 "bad owner or modes for %.200s", 388 pw->pw_name, user_hostfile); 389 auth_debug_add("Ignored %.200s: bad ownership or modes", 390 user_hostfile); 391 } else { 392 temporarily_use_uid(pw); 393 load_hostkeys(hostkeys, host, user_hostfile, 0); 394 restore_uid(); 395 } 396 free(user_hostfile); 397 } 398 host_status = check_key_in_hostkeys(hostkeys, key, &found); 399 if (host_status == HOST_REVOKED) 400 error("WARNING: revoked key for %s attempted authentication", 401 host); 402 else if (host_status == HOST_OK) 403 debug_f("key for %s found at %s:%ld", 404 found->host, found->file, found->line); 405 else 406 debug_f("key for host %s not found", host); 407 408 free_hostkeys(hostkeys); 409 410 return host_status; 411 } 412 413 struct passwd * 414 getpwnamallow(struct ssh *ssh, const char *user) 415 { 416 extern login_cap_t *lc; 417 auth_session_t *as; 418 struct passwd *pw; 419 struct connection_info *ci; 420 u_int i; 421 422 ci = server_get_connection_info(ssh, 1, options.use_dns); 423 ci->user = user; 424 parse_server_match_config(&options, &includes, ci); 425 log_change_level(options.log_level); 426 log_verbose_reset(); 427 for (i = 0; i < options.num_log_verbose; i++) 428 log_verbose_add(options.log_verbose[i]); 429 server_process_permitopen(ssh); 430 431 pw = getpwnam(user); 432 if (pw == NULL) { 433 logit("Invalid user %.100s from %.100s port %d", 434 user, ssh_remote_ipaddr(ssh), ssh_remote_port(ssh)); 435 return (NULL); 436 } 437 if (!allowed_user(ssh, pw)) 438 return (NULL); 439 if ((lc = login_getclass(pw->pw_class)) == NULL) { 440 debug("unable to get login class: %s", user); 441 return (NULL); 442 } 443 if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 || 444 auth_approval(as, lc, pw->pw_name, "ssh") <= 0) { 445 debug("Approval failure for %s", user); 446 pw = NULL; 447 } 448 if (as != NULL) 449 auth_close(as); 450 if (pw != NULL) 451 return (pwcopy(pw)); 452 return (NULL); 453 } 454 455 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */ 456 int 457 auth_key_is_revoked(struct sshkey *key) 458 { 459 char *fp = NULL; 460 int r; 461 462 if (options.revoked_keys_file == NULL) 463 return 0; 464 if ((fp = sshkey_fingerprint(key, options.fingerprint_hash, 465 SSH_FP_DEFAULT)) == NULL) { 466 r = SSH_ERR_ALLOC_FAIL; 467 error_fr(r, "fingerprint key"); 468 goto out; 469 } 470 471 r = sshkey_check_revoked(key, options.revoked_keys_file); 472 switch (r) { 473 case 0: 474 break; /* not revoked */ 475 case SSH_ERR_KEY_REVOKED: 476 error("Authentication key %s %s revoked by file %s", 477 sshkey_type(key), fp, options.revoked_keys_file); 478 goto out; 479 default: 480 error_r(r, "Error checking authentication key %s %s in " 481 "revoked keys file %s", sshkey_type(key), fp, 482 options.revoked_keys_file); 483 goto out; 484 } 485 486 /* Success */ 487 r = 0; 488 489 out: 490 free(fp); 491 return r == 0 ? 0 : 1; 492 } 493 494 void 495 auth_debug_add(const char *fmt,...) 496 { 497 char buf[1024]; 498 va_list args; 499 int r; 500 501 va_start(args, fmt); 502 vsnprintf(buf, sizeof(buf), fmt, args); 503 va_end(args); 504 debug3("%s", buf); 505 if (auth_debug != NULL) 506 if ((r = sshbuf_put_cstring(auth_debug, buf)) != 0) 507 fatal_fr(r, "sshbuf_put_cstring"); 508 } 509 510 void 511 auth_debug_send(struct ssh *ssh) 512 { 513 char *msg; 514 int r; 515 516 if (auth_debug == NULL) 517 return; 518 while (sshbuf_len(auth_debug) != 0) { 519 if ((r = sshbuf_get_cstring(auth_debug, &msg, NULL)) != 0) 520 fatal_fr(r, "sshbuf_get_cstring"); 521 ssh_packet_send_debug(ssh, "%s", msg); 522 free(msg); 523 } 524 } 525 526 void 527 auth_debug_reset(void) 528 { 529 if (auth_debug != NULL) 530 sshbuf_reset(auth_debug); 531 else if ((auth_debug = sshbuf_new()) == NULL) 532 fatal_f("sshbuf_new failed"); 533 } 534 535 struct passwd * 536 fakepw(void) 537 { 538 static int done = 0; 539 static struct passwd fake; 540 const char hashchars[] = "./ABCDEFGHIJKLMNOPQRSTUVWXYZ" 541 "abcdefghijklmnopqrstuvwxyz0123456789"; /* from bcrypt.c */ 542 char *cp; 543 544 if (done) 545 return (&fake); 546 547 memset(&fake, 0, sizeof(fake)); 548 fake.pw_name = "NOUSER"; 549 fake.pw_passwd = xstrdup("$2a$10$" 550 "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"); 551 for (cp = fake.pw_passwd + 7; *cp != '\0'; cp++) 552 *cp = hashchars[arc4random_uniform(sizeof(hashchars) - 1)]; 553 fake.pw_gecos = "NOUSER"; 554 fake.pw_uid = (uid_t)-1; 555 fake.pw_gid = (gid_t)-1; 556 fake.pw_class = ""; 557 fake.pw_dir = "/nonexist"; 558 fake.pw_shell = "/nonexist"; 559 done = 1; 560 561 return (&fake); 562 } 563 564 /* 565 * Return the canonical name of the host in the other side of the current 566 * connection. The host name is cached, so it is efficient to call this 567 * several times. 568 */ 569 570 const char * 571 auth_get_canonical_hostname(struct ssh *ssh, int use_dns) 572 { 573 static char *dnsname; 574 575 if (!use_dns) 576 return ssh_remote_ipaddr(ssh); 577 if (dnsname != NULL) 578 return dnsname; 579 dnsname = ssh_remote_hostname(ssh); 580 return dnsname; 581 } 582 583 /* These functions link key/cert options to the auth framework */ 584 585 /* Log sshauthopt options locally and (optionally) for remote transmission */ 586 void 587 auth_log_authopts(const char *loc, const struct sshauthopt *opts, int do_remote) 588 { 589 int do_env = options.permit_user_env && opts->nenv > 0; 590 int do_permitopen = opts->npermitopen > 0 && 591 (options.allow_tcp_forwarding & FORWARD_LOCAL) != 0; 592 int do_permitlisten = opts->npermitlisten > 0 && 593 (options.allow_tcp_forwarding & FORWARD_REMOTE) != 0; 594 size_t i; 595 char msg[1024], buf[64]; 596 597 snprintf(buf, sizeof(buf), "%d", opts->force_tun_device); 598 /* Try to keep this alphabetically sorted */ 599 snprintf(msg, sizeof(msg), "key options:%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s", 600 opts->permit_agent_forwarding_flag ? " agent-forwarding" : "", 601 opts->force_command == NULL ? "" : " command", 602 do_env ? " environment" : "", 603 opts->valid_before == 0 ? "" : "expires", 604 opts->no_require_user_presence ? " no-touch-required" : "", 605 do_permitopen ? " permitopen" : "", 606 do_permitlisten ? " permitlisten" : "", 607 opts->permit_port_forwarding_flag ? " port-forwarding" : "", 608 opts->cert_principals == NULL ? "" : " principals", 609 opts->permit_pty_flag ? " pty" : "", 610 opts->require_verify ? " uv" : "", 611 opts->force_tun_device == -1 ? "" : " tun=", 612 opts->force_tun_device == -1 ? "" : buf, 613 opts->permit_user_rc ? " user-rc" : "", 614 opts->permit_x11_forwarding_flag ? " x11-forwarding" : ""); 615 616 debug("%s: %s", loc, msg); 617 if (do_remote) 618 auth_debug_add("%s: %s", loc, msg); 619 620 if (options.permit_user_env) { 621 for (i = 0; i < opts->nenv; i++) { 622 debug("%s: environment: %s", loc, opts->env[i]); 623 if (do_remote) { 624 auth_debug_add("%s: environment: %s", 625 loc, opts->env[i]); 626 } 627 } 628 } 629 630 /* Go into a little more details for the local logs. */ 631 if (opts->valid_before != 0) { 632 format_absolute_time(opts->valid_before, buf, sizeof(buf)); 633 debug("%s: expires at %s", loc, buf); 634 } 635 if (opts->cert_principals != NULL) { 636 debug("%s: authorized principals: \"%s\"", 637 loc, opts->cert_principals); 638 } 639 if (opts->force_command != NULL) 640 debug("%s: forced command: \"%s\"", loc, opts->force_command); 641 if (do_permitopen) { 642 for (i = 0; i < opts->npermitopen; i++) { 643 debug("%s: permitted open: %s", 644 loc, opts->permitopen[i]); 645 } 646 } 647 if (do_permitlisten) { 648 for (i = 0; i < opts->npermitlisten; i++) { 649 debug("%s: permitted listen: %s", 650 loc, opts->permitlisten[i]); 651 } 652 } 653 } 654 655 /* Activate a new set of key/cert options; merging with what is there. */ 656 int 657 auth_activate_options(struct ssh *ssh, struct sshauthopt *opts) 658 { 659 struct sshauthopt *old = auth_opts; 660 const char *emsg = NULL; 661 662 debug_f("setting new authentication options"); 663 if ((auth_opts = sshauthopt_merge(old, opts, &emsg)) == NULL) { 664 error("Inconsistent authentication options: %s", emsg); 665 return -1; 666 } 667 return 0; 668 } 669 670 /* Disable forwarding, etc for the session */ 671 void 672 auth_restrict_session(struct ssh *ssh) 673 { 674 struct sshauthopt *restricted; 675 676 debug_f("restricting session"); 677 678 /* A blank sshauthopt defaults to permitting nothing */ 679 if ((restricted = sshauthopt_new()) == NULL) 680 fatal_f("sshauthopt_new failed"); 681 restricted->permit_pty_flag = 1; 682 restricted->restricted = 1; 683 684 if (auth_activate_options(ssh, restricted) != 0) 685 fatal_f("failed to restrict session"); 686 sshauthopt_free(restricted); 687 } 688