auth.c

   1 /* $OpenBSD: auth.c,v 1.91 2010/11/29 23:45:51 djm Exp $ */
   2 /*
   3  * Copyright (c) 2000 Markus Friedl.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "includes.h"
  27
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <sys/param.h>
  31
  32 #include <netinet/in.h>
  33
  34 #include <errno.h>
  35 #include <fcntl.h>
  36 #ifdef HAVE_PATHS_H
  37 # include <paths.h>
  38 #endif
  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 #ifdef HAVE_LIBGEN_H
  47 #include <libgen.h>
  48 #endif
  49 #include <stdarg.h>
  50 #include <stdio.h>
  51 #include <string.h>
  52 #include <unistd.h>
  53
  54 #include "xmalloc.h"
  55 #include "match.h"
  56 #include "groupaccess.h"
  57 #include "log.h"
  58 #include "buffer.h"
  59 #include "servconf.h"
  60 #include "key.h"
  61 #include "hostfile.h"
  62 #include "auth.h"
  63 #include "auth-options.h"
  64 #include "canohost.h"
  65 #include "uidswap.h"
  66 #include "misc.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
  75 /* import */
  76 extern ServerOptions options;
  77 extern int use_privsep;
  78 extern Buffer loginmsg;
  79 extern struct passwd *privsep_pw;
  80
  81 /* Debugging messages */
  82 Buffer auth_debug;
  83 int auth_debug_init;
  84
  85 /*
  86  * Check if the user is allowed to log in via ssh. If user is listed
  87  * in DenyUsers or one of user's groups is listed in DenyGroups, false
  88  * will be returned. If AllowUsers isn't empty and user isn't listed
  89  * there, or if AllowGroups isn't empty and one of user's groups isn't
  90  * listed there, false will be returned.
  91  * If the user's shell is not executable, false will be returned.
  92  * Otherwise true is returned.
  93  */
  94 int
  95 allowed_user(struct passwd * pw)
  96 {
  97         struct stat st;
  98         const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
  99         u_int i;
 100 #ifdef USE_SHADOW
 101         struct spwd *spw = NULL;
 102 #endif
 103
 104         /* Shouldn't be called if pw is NULL, but better safe than sorry... */
 105         if (!pw || !pw->pw_name)
 106                 return 0;
 107
 108 #ifdef USE_SHADOW
 109         if (!options.use_pam)
 110                 spw = getspnam(pw->pw_name);
 111 #ifdef HAS_SHADOW_EXPIRE
 112         if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
 113                 return 0;
 114 #endif /* HAS_SHADOW_EXPIRE */
 115 #endif /* USE_SHADOW */
 116
 117         /* grab passwd field for locked account check */
 118         passwd = pw->pw_passwd;
 119 #ifdef USE_SHADOW
 120         if (spw != NULL)
 121 #ifdef USE_LIBIAF
 122                 passwd = get_iaf_password(pw);
 123 #else
 124                 passwd = spw->sp_pwdp;
 125 #endif /* USE_LIBIAF */
 126 #endif
 127
 128         /* check for locked account */
 129         if (!options.use_pam && passwd && *passwd) {
 130                 int locked = 0;
 131
 132 #ifdef LOCKED_PASSWD_STRING
 133                 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
 134                          locked = 1;
 135 #endif
 136 #ifdef LOCKED_PASSWD_PREFIX
 137                 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
 138                     strlen(LOCKED_PASSWD_PREFIX)) == 0)
 139                          locked = 1;
 140 #endif
 141 #ifdef LOCKED_PASSWD_SUBSTR
 142                 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
 143                         locked = 1;
 144 #endif
 145 #ifdef USE_LIBIAF
 146                 free((void *) passwd);
 147 #endif /* USE_LIBIAF */
 148                 if (locked) {
 149                         logit("User %.100s not allowed because account is locked",
 150                             pw->pw_name);
 151                         return 0;
 152                 }
 153         }
 154
 155         /*
 156          * Deny if shell does not exist or is not executable unless we
 157          * are chrooting.
 158          */
 159         if (options.chroot_directory == NULL ||
 160             strcasecmp(options.chroot_directory, "none") == 0) {
 161                 char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
 162                     _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
 163
 164                 if (stat(shell, &st) != 0) {
 165                         logit("User %.100s not allowed because shell %.100s "
 166                             "does not exist", pw->pw_name, shell);
 167                         xfree(shell);
 168                         return 0;
 169                 }
 170                 if (S_ISREG(st.st_mode) == 0 ||
 171                     (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
 172                         logit("User %.100s not allowed because shell %.100s "
 173                             "is not executable", pw->pw_name, shell);
 174                         xfree(shell);
 175                         return 0;
 176                 }
 177                 xfree(shell);
 178         }
 179
 180         if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
 181             options.num_deny_groups > 0 || options.num_allow_groups > 0) {
 182                 hostname = get_canonical_hostname(options.use_dns);
 183                 ipaddr = get_remote_ipaddr();
 184         }
 185
 186         /* Return false if user is listed in DenyUsers */
 187         if (options.num_deny_users > 0) {
 188                 for (i = 0; i < options.num_deny_users; i++)
 189                         if (match_user(pw->pw_name, hostname, ipaddr,
 190                             options.deny_users[i])) {
 191                                 logit("User %.100s from %.100s not allowed "
 192                                     "because listed in DenyUsers",
 193                                     pw->pw_name, hostname);
 194                                 return 0;
 195                         }
 196         }
 197         /* Return false if AllowUsers isn't empty and user isn't listed there */
 198         if (options.num_allow_users > 0) {
 199                 for (i = 0; i < options.num_allow_users; i++)
 200                         if (match_user(pw->pw_name, hostname, ipaddr,
 201                             options.allow_users[i]))
 202                                 break;
 203                 /* i < options.num_allow_users iff we break for loop */
 204                 if (i >= options.num_allow_users) {
 205                         logit("User %.100s from %.100s not allowed because "
 206                             "not listed in AllowUsers", pw->pw_name, hostname);
 207                         return 0;
 208                 }
 209         }
 210         if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
 211                 /* Get the user's group access list (primary and supplementary) */
 212                 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
 213                         logit("User %.100s from %.100s not allowed because "
 214                             "not in any group", pw->pw_name, hostname);
 215                         return 0;
 216                 }
 217
 218                 /* Return false if one of user's groups is listed in DenyGroups */
 219                 if (options.num_deny_groups > 0)
 220                         if (ga_match(options.deny_groups,
 221                             options.num_deny_groups)) {
 222                                 ga_free();
 223                                 logit("User %.100s from %.100s not allowed "
 224                                     "because a group is listed in DenyGroups",
 225                                     pw->pw_name, hostname);
 226                                 return 0;
 227                         }
 228                 /*
 229                  * Return false if AllowGroups isn't empty and one of user's groups
 230                  * isn't listed there
 231                  */
 232                 if (options.num_allow_groups > 0)
 233                         if (!ga_match(options.allow_groups,
 234                             options.num_allow_groups)) {
 235                                 ga_free();
 236                                 logit("User %.100s from %.100s not allowed "
 237                                     "because none of user's groups are listed "
 238                                     "in AllowGroups", pw->pw_name, hostname);
 239                                 return 0;
 240                         }
 241                 ga_free();
 242         }
 243
 244 #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
 245         if (!sys_auth_allowed_user(pw, &loginmsg))
 246                 return 0;
 247 #endif
 248
 249         /* We found no reason not to let this user try to log on... */
 250         return 1;
 251 }
 252
 253 void
 254 auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
 255 {
 256         void (*authlog) (const char *fmt,...) = verbose;
 257         char *authmsg;
 258
 259         if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
 260                 return;
 261
 262         /* Raise logging level */
 263         if (authenticated == 1 ||
 264             !authctxt->valid ||
 265             authctxt->failures >= options.max_authtries / 2 ||
 266             strcmp(method, "password") == 0)
 267                 authlog = logit;
 268
 269         if (authctxt->postponed)
 270                 authmsg = "Postponed";
 271         else
 272                 authmsg = authenticated ? "Accepted" : "Failed";
 273
 274         authlog("%s %s for %s%.100s from %.200s port %d%s",
 275             authmsg,
 276             method,
 277             authctxt->valid ? "" : "invalid user ",
 278             authctxt->user,
 279             get_remote_ipaddr(),
 280             get_remote_port(),
 281             info);
 282
 283 #ifdef CUSTOM_FAILED_LOGIN
 284         if (authenticated == 0 && !authctxt->postponed &&
 285             (strcmp(method, "password") == 0 ||
 286             strncmp(method, "keyboard-interactive", 20) == 0 ||
 287             strcmp(method, "challenge-response") == 0))
 288                 record_failed_login(authctxt->user,
 289                     get_canonical_hostname(options.use_dns), "ssh");
 290 # ifdef WITH_AIXAUTHENTICATE
 291         if (authenticated)
 292                 sys_auth_record_login(authctxt->user,
 293                     get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
 294 # endif
 295 #endif
 296 #ifdef SSH_AUDIT_EVENTS
 297         if (authenticated == 0 && !authctxt->postponed)
 298                 audit_event(audit_classify_auth(method));
 299 #endif
 300 }
 301
 302 /*
 303  * Check whether root logins are disallowed.
 304  */
 305 int
 306 auth_root_allowed(char *method)
 307 {
 308         switch (options.permit_root_login) {
 309         case PERMIT_YES:
 310                 return 1;
 311         case PERMIT_NO_PASSWD:
 312                 if (strcmp(method, "password") != 0)
 313                         return 1;
 314                 break;
 315         case PERMIT_FORCED_ONLY:
 316                 if (forced_command) {
 317                         logit("Root login accepted for forced command.");
 318                         return 1;
 319                 }
 320                 break;
 321         }
 322         logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
 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 static char *
 335 expand_authorized_keys(const char *filename, struct passwd *pw)
 336 {
 337         char *file, ret[MAXPATHLEN];
 338         int i;
 339
 340         file = percent_expand(filename, "h", pw->pw_dir,
 341             "u", pw->pw_name, (char *)NULL);
 342
 343         /*
 344          * Ensure that filename starts anchored. If not, be backward
 345          * compatible and prepend the '%h/'
 346          */
 347         if (*file == '/')
 348                 return (file);
 349
 350         i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
 351         if (i < 0 || (size_t)i >= sizeof(ret))
 352                 fatal("expand_authorized_keys: path too long");
 353         xfree(file);
 354         return (xstrdup(ret));
 355 }
 356
 357 char *
 358 authorized_keys_file(struct passwd *pw)
 359 {
 360         return expand_authorized_keys(options.authorized_keys_file, pw);
 361 }
 362
 363 char *
 364 authorized_keys_file2(struct passwd *pw)
 365 {
 366         return expand_authorized_keys(options.authorized_keys_file2, pw);
 367 }
 368
 369 char *
 370 authorized_principals_file(struct passwd *pw)
 371 {
 372         if (options.authorized_principals_file == NULL)
 373                 return NULL;
 374         return expand_authorized_keys(options.authorized_principals_file, pw);
 375 }
 376
 377 /* return ok if key exists in sysfile or userfile */
 378 HostStatus
 379 check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
 380     const char *sysfile, const char *userfile)
 381 {
 382         char *user_hostfile;
 383         struct stat st;
 384         HostStatus host_status;
 385         struct hostkeys *hostkeys;
 386         const struct hostkey_entry *found;
 387
 388         hostkeys = init_hostkeys();
 389         load_hostkeys(hostkeys, host, sysfile);
 390         if (userfile != NULL) {
 391                 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
 392                 if (options.strict_modes &&
 393                     (stat(user_hostfile, &st) == 0) &&
 394                     ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
 395                     (st.st_mode & 022) != 0)) {
 396                         logit("Authentication refused for %.100s: "
 397                             "bad owner or modes for %.200s",
 398                             pw->pw_name, user_hostfile);
 399                         auth_debug_add("Ignored %.200s: bad ownership or modes",
 400                             user_hostfile);
 401                 } else {
 402                         temporarily_use_uid(pw);
 403                         load_hostkeys(hostkeys, host, user_hostfile);
 404                         restore_uid();
 405                 }
 406                 xfree(user_hostfile);
 407         }
 408         host_status = check_key_in_hostkeys(hostkeys, key, &found);
 409         if (host_status == HOST_REVOKED)
 410                 error("WARNING: revoked key for %s attempted authentication",
 411                     found->host);
 412         else if (host_status == HOST_OK)
 413                 debug("%s: key for %s found at %s:%ld", __func__,
 414                     found->host, found->file, found->line);
 415         else
 416                 debug("%s: key for host %s not found", __func__, host);
 417
 418         free_hostkeys(hostkeys);
 419
 420         return host_status;
 421 }
 422
 423
 424 /*
 425  * Check a given file for security. This is defined as all components
 426  * of the path to the file must be owned by either the owner of
 427  * of the file or root and no directories must be group or world writable.
 428  *
 429  * XXX Should any specific check be done for sym links ?
 430  *
 431  * Takes an open file descriptor, the file name, a uid and and
 432  * error buffer plus max size as arguments.
 433  *
 434  * Returns 0 on success and -1 on failure
 435  */
 436 static int
 437 secure_filename(FILE *f, const char *file, struct passwd *pw,
 438     char *err, size_t errlen)
 439 {
 440         uid_t uid = pw->pw_uid;
 441         char buf[MAXPATHLEN], homedir[MAXPATHLEN];
 442         char *cp;
 443         int comparehome = 0;
 444         struct stat st;
 445
 446         if (realpath(file, buf) == NULL) {
 447                 snprintf(err, errlen, "realpath %s failed: %s", file,
 448                     strerror(errno));
 449                 return -1;
 450         }
 451         if (realpath(pw->pw_dir, homedir) != NULL)
 452                 comparehome = 1;
 453
 454         /* check the open file to avoid races */
 455         if (fstat(fileno(f), &st) < 0 ||
 456             (st.st_uid != 0 && st.st_uid != uid) ||
 457             (st.st_mode & 022) != 0) {
 458                 snprintf(err, errlen, "bad ownership or modes for file %s",
 459                     buf);
 460                 return -1;
 461         }
 462
 463         /* for each component of the canonical path, walking upwards */
 464         for (;;) {
 465                 if ((cp = dirname(buf)) == NULL) {
 466                         snprintf(err, errlen, "dirname() failed");
 467                         return -1;
 468                 }
 469                 strlcpy(buf, cp, sizeof(buf));
 470
 471                 debug3("secure_filename: checking '%s'", buf);
 472                 if (stat(buf, &st) < 0 ||
 473                     (st.st_uid != 0 && st.st_uid != uid) ||
 474                     (st.st_mode & 022) != 0) {
 475                         snprintf(err, errlen,
 476                             "bad ownership or modes for directory %s", buf);
 477                         return -1;
 478                 }
 479
 480                 /* If are past the homedir then we can stop */
 481                 if (comparehome && strcmp(homedir, buf) == 0) {
 482                         debug3("secure_filename: terminating check at '%s'",
 483                             buf);
 484                         break;
 485                 }
 486                 /*
 487                  * dirname should always complete with a "/" path,
 488                  * but we can be paranoid and check for "." too
 489                  */
 490                 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
 491                         break;
 492         }
 493         return 0;
 494 }
 495
 496 static FILE *
 497 auth_openfile(const char *file, struct passwd *pw, int strict_modes,
 498     int log_missing, char *file_type)
 499 {
 500         char line[1024];
 501         struct stat st;
 502         int fd;
 503         FILE *f;
 504
 505         if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
 506                 if (log_missing || errno != ENOENT)
 507                         debug("Could not open %s '%s': %s", file_type, file,
 508                            strerror(errno));
 509                 return NULL;
 510         }
 511
 512         if (fstat(fd, &st) < 0) {
 513                 close(fd);
 514                 return NULL;
 515         }
 516         if (!S_ISREG(st.st_mode)) {
 517                 logit("User %s %s %s is not a regular file",
 518                     pw->pw_name, file_type, file);
 519                 close(fd);
 520                 return NULL;
 521         }
 522         unset_nonblock(fd);
 523         if ((f = fdopen(fd, "r")) == NULL) {
 524                 close(fd);
 525                 return NULL;
 526         }
 527         if (strict_modes &&
 528             secure_filename(f, file, pw, line, sizeof(line)) != 0) {
 529                 fclose(f);
 530                 logit("Authentication refused: %s", line);
 531                 auth_debug_add("Ignored %s: %s", file_type, line);
 532                 return NULL;
 533         }
 534
 535         return f;
 536 }
 537
 538
 539 FILE *
 540 auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
 541 {
 542         return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
 543 }
 544
 545 FILE *
 546 auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
 547 {
 548         return auth_openfile(file, pw, strict_modes, 0,
 549             "authorized principals");
 550 }
 551
 552 struct passwd *
 553 getpwnamallow(const char *user)
 554 {
 555 #ifdef HAVE_LOGIN_CAP
 556         extern login_cap_t *lc;
 557 #ifdef BSD_AUTH
 558         auth_session_t *as;
 559 #endif
 560 #endif
 561         struct passwd *pw;
 562
 563         parse_server_match_config(&options, user,
 564             get_canonical_hostname(options.use_dns), get_remote_ipaddr());
 565
 566 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
 567         aix_setauthdb(user);
 568 #endif
 569
 570         pw = getpwnam(user);
 571
 572 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
 573         aix_restoreauthdb();
 574 #endif
 575 #ifdef HAVE_CYGWIN
 576         /*
 577          * Windows usernames are case-insensitive.  To avoid later problems
 578          * when trying to match the username, the user is only allowed to
 579          * login if the username is given in the same case as stored in the
 580          * user database.
 581          */
 582         if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
 583                 logit("Login name %.100s does not match stored username %.100s",
 584                     user, pw->pw_name);
 585                 pw = NULL;
 586         }
 587 #endif
 588         if (pw == NULL) {
 589                 logit("Invalid user %.100s from %.100s",
 590                     user, get_remote_ipaddr());
 591 #ifdef CUSTOM_FAILED_LOGIN
 592                 record_failed_login(user,
 593                     get_canonical_hostname(options.use_dns), "ssh");
 594 #endif
 595 #ifdef SSH_AUDIT_EVENTS
 596                 audit_event(SSH_INVALID_USER);
 597 #endif /* SSH_AUDIT_EVENTS */
 598                 return (NULL);
 599         }
 600         if (!allowed_user(pw))
 601                 return (NULL);
 602 #ifdef HAVE_LOGIN_CAP
 603         if ((lc = login_getclass(pw->pw_class)) == NULL) {
 604                 debug("unable to get login class: %s", user);
 605                 return (NULL);
 606         }
 607 #ifdef BSD_AUTH
 608         if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
 609             auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
 610                 debug("Approval failure for %s", user);
 611                 pw = NULL;
 612         }
 613         if (as != NULL)
 614                 auth_close(as);
 615 #endif
 616 #endif
 617         if (pw != NULL)
 618                 return (pwcopy(pw));
 619         return (NULL);
 620 }
 621
 622 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
 623 int
 624 auth_key_is_revoked(Key *key)
 625 {
 626         char *key_fp;
 627
 628         if (options.revoked_keys_file == NULL)
 629                 return 0;
 630
 631         switch (key_in_file(key, options.revoked_keys_file, 0)) {
 632         case 0:
 633                 /* key not revoked */
 634                 return 0;
 635         case -1:
 636                 /* Error opening revoked_keys_file: refuse all keys */
 637                 error("Revoked keys file is unreadable: refusing public key "
 638                     "authentication");
 639                 return 1;
 640         case 1:
 641                 /* Key revoked */
 642                 key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 643                 error("WARNING: authentication attempt with a revoked "
 644                     "%s key %s ", key_type(key), key_fp);
 645                 xfree(key_fp);
 646                 return 1;
 647         }
 648         fatal("key_in_file returned junk");
 649 }
 650
 651 void
 652 auth_debug_add(const char *fmt,...)
 653 {
 654         char buf[1024];
 655         va_list args;
 656
 657         if (!auth_debug_init)
 658                 return;
 659
 660         va_start(args, fmt);
 661         vsnprintf(buf, sizeof(buf), fmt, args);
 662         va_end(args);
 663         buffer_put_cstring(&auth_debug, buf);
 664 }
 665
 666 void
 667 auth_debug_send(void)
 668 {
 669         char *msg;
 670
 671         if (!auth_debug_init)
 672                 return;
 673         while (buffer_len(&auth_debug)) {
 674                 msg = buffer_get_string(&auth_debug, NULL);
 675                 packet_send_debug("%s", msg);
 676                 xfree(msg);
 677         }
 678 }
 679
 680 void
 681 auth_debug_reset(void)
 682 {
 683         if (auth_debug_init)
 684                 buffer_clear(&auth_debug);
 685         else {
 686                 buffer_init(&auth_debug);
 687                 auth_debug_init = 1;
 688         }
 689 }
 690
 691 struct passwd *
 692 fakepw(void)
 693 {
 694         static struct passwd fake;
 695
 696         memset(&fake, 0, sizeof(fake));
 697         fake.pw_name = "NOUSER";
 698         fake.pw_passwd =
 699             "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
 700         fake.pw_gecos = "NOUSER";
 701         fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
 702         fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
 703 #ifdef HAVE_PW_CLASS_IN_PASSWD
 704         fake.pw_class = "";
 705 #endif
 706         fake.pw_dir = "/nonexist";
 707         fake.pw_shell = "/nonexist";
 708
 709         return (&fake);
 710 }