crypto/openssh/auth.c

   1 /* $OpenBSD: auth.c,v 1.106 2014/07/15 15:54:14 millert 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 "misc.h"
  60 #include "servconf.h"
  61 #include "key.h"
  62 #include "hostfile.h"
  63 #include "auth.h"
  64 #include "auth-options.h"
  65 #include "canohost.h"
  66 #include "uidswap.h"
  67 #include "packet.h"
  68 #include "loginrec.h"
  69 #ifdef GSSAPI
  70 #include "ssh-gss.h"
  71 #endif
  72 #include "authfile.h"
  73 #include "monitor_wrap.h"
  74 #include "krl.h"
  75 #include "compat.h"
  76
  77 /* import */
  78 extern ServerOptions options;
  79 extern int use_privsep;
  80 extern Buffer loginmsg;
  81 extern struct passwd *privsep_pw;
  82
  83 /* Debugging messages */
  84 Buffer auth_debug;
  85 int auth_debug_init;
  86
  87 /*
  88  * Check if the user is allowed to log in via ssh. If user is listed
  89  * in DenyUsers or one of user's groups is listed in DenyGroups, false
  90  * will be returned. If AllowUsers isn't empty and user isn't listed
  91  * there, or if AllowGroups isn't empty and one of user's groups isn't
  92  * listed there, false will be returned.
  93  * If the user's shell is not executable, false will be returned.
  94  * Otherwise true is returned.
  95  */
  96 int
  97 allowed_user(struct passwd * pw)
  98 {
  99         struct stat st;
 100         const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
 101         u_int i;
 102 #ifdef USE_SHADOW
 103         struct spwd *spw = NULL;
 104 #endif
 105
 106         /* Shouldn't be called if pw is NULL, but better safe than sorry... */
 107         if (!pw || !pw->pw_name)
 108                 return 0;
 109
 110 #ifdef USE_SHADOW
 111         if (!options.use_pam)
 112                 spw = getspnam(pw->pw_name);
 113 #ifdef HAS_SHADOW_EXPIRE
 114         if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
 115                 return 0;
 116 #endif /* HAS_SHADOW_EXPIRE */
 117 #endif /* USE_SHADOW */
 118
 119         /* grab passwd field for locked account check */
 120         passwd = pw->pw_passwd;
 121 #ifdef USE_SHADOW
 122         if (spw != NULL)
 123 #ifdef USE_LIBIAF
 124                 passwd = get_iaf_password(pw);
 125 #else
 126                 passwd = spw->sp_pwdp;
 127 #endif /* USE_LIBIAF */
 128 #endif
 129
 130         /* check for locked account */
 131         if (!options.use_pam && passwd && *passwd) {
 132                 int locked = 0;
 133
 134 #ifdef LOCKED_PASSWD_STRING
 135                 if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
 136                          locked = 1;
 137 #endif
 138 #ifdef LOCKED_PASSWD_PREFIX
 139                 if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
 140                     strlen(LOCKED_PASSWD_PREFIX)) == 0)
 141                          locked = 1;
 142 #endif
 143 #ifdef LOCKED_PASSWD_SUBSTR
 144                 if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
 145                         locked = 1;
 146 #endif
 147 #ifdef USE_LIBIAF
 148                 free((void *) passwd);
 149 #endif /* USE_LIBIAF */
 150                 if (locked) {
 151                         logit("User %.100s not allowed because account is locked",
 152                             pw->pw_name);
 153                         return 0;
 154                 }
 155         }
 156
 157         /*
 158          * Deny if shell does not exist or is not executable unless we
 159          * are chrooting.
 160          */
 161         if (options.chroot_directory == NULL ||
 162             strcasecmp(options.chroot_directory, "none") == 0) {
 163                 char *shell = xstrdup((pw->pw_shell[0] == '\0') ?
 164                     _PATH_BSHELL : pw->pw_shell); /* empty = /bin/sh */
 165
 166                 if (stat(shell, &st) != 0) {
 167                         logit("User %.100s not allowed because shell %.100s "
 168                             "does not exist", pw->pw_name, shell);
 169                         free(shell);
 170                         return 0;
 171                 }
 172                 if (S_ISREG(st.st_mode) == 0 ||
 173                     (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
 174                         logit("User %.100s not allowed because shell %.100s "
 175                             "is not executable", pw->pw_name, shell);
 176                         free(shell);
 177                         return 0;
 178                 }
 179                 free(shell);
 180         }
 181
 182         if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
 183             options.num_deny_groups > 0 || options.num_allow_groups > 0) {
 184                 hostname = get_canonical_hostname(options.use_dns);
 185                 ipaddr = get_remote_ipaddr();
 186         }
 187
 188         /* Return false if user is listed in DenyUsers */
 189         if (options.num_deny_users > 0) {
 190                 for (i = 0; i < options.num_deny_users; i++)
 191                         if (match_user(pw->pw_name, hostname, ipaddr,
 192                             options.deny_users[i])) {
 193                                 logit("User %.100s from %.100s not allowed "
 194                                     "because listed in DenyUsers",
 195                                     pw->pw_name, hostname);
 196                                 return 0;
 197                         }
 198         }
 199         /* Return false if AllowUsers isn't empty and user isn't listed there */
 200         if (options.num_allow_users > 0) {
 201                 for (i = 0; i < options.num_allow_users; i++)
 202                         if (match_user(pw->pw_name, hostname, ipaddr,
 203                             options.allow_users[i]))
 204                                 break;
 205                 /* i < options.num_allow_users iff we break for loop */
 206                 if (i >= options.num_allow_users) {
 207                         logit("User %.100s from %.100s not allowed because "
 208                             "not listed in AllowUsers", pw->pw_name, hostname);
 209                         return 0;
 210                 }
 211         }
 212         if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
 213                 /* Get the user's group access list (primary and supplementary) */
 214                 if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
 215                         logit("User %.100s from %.100s not allowed because "
 216                             "not in any group", pw->pw_name, hostname);
 217                         return 0;
 218                 }
 219
 220                 /* Return false if one of user's groups is listed in DenyGroups */
 221                 if (options.num_deny_groups > 0)
 222                         if (ga_match(options.deny_groups,
 223                             options.num_deny_groups)) {
 224                                 ga_free();
 225                                 logit("User %.100s from %.100s not allowed "
 226                                     "because a group is listed in DenyGroups",
 227                                     pw->pw_name, hostname);
 228                                 return 0;
 229                         }
 230                 /*
 231                  * Return false if AllowGroups isn't empty and one of user's groups
 232                  * isn't listed there
 233                  */
 234                 if (options.num_allow_groups > 0)
 235                         if (!ga_match(options.allow_groups,
 236                             options.num_allow_groups)) {
 237                                 ga_free();
 238                                 logit("User %.100s from %.100s not allowed "
 239                                     "because none of user's groups are listed "
 240                                     "in AllowGroups", pw->pw_name, hostname);
 241                                 return 0;
 242                         }
 243                 ga_free();
 244         }
 245
 246 #ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
 247         if (!sys_auth_allowed_user(pw, &loginmsg))
 248                 return 0;
 249 #endif
 250
 251         /* We found no reason not to let this user try to log on... */
 252         return 1;
 253 }
 254
 255 void
 256 auth_info(Authctxt *authctxt, const char *fmt, ...)
 257 {
 258         va_list ap;
 259         int i;
 260
 261         free(authctxt->info);
 262         authctxt->info = NULL;
 263
 264         va_start(ap, fmt);
 265         i = vasprintf(&authctxt->info, fmt, ap);
 266         va_end(ap);
 267
 268         if (i < 0 || authctxt->info == NULL)
 269                 fatal("vasprintf failed");
 270 }
 271
 272 void
 273 auth_log(Authctxt *authctxt, int authenticated, int partial,
 274     const char *method, const char *submethod)
 275 {
 276         void (*authlog) (const char *fmt,...) = verbose;
 277         char *authmsg;
 278
 279         if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
 280                 return;
 281
 282         /* Raise logging level */
 283         if (authenticated == 1 ||
 284             !authctxt->valid ||
 285             authctxt->failures >= options.max_authtries / 2 ||
 286             strcmp(method, "password") == 0)
 287                 authlog = logit;
 288
 289         if (authctxt->postponed)
 290                 authmsg = "Postponed";
 291         else if (partial)
 292                 authmsg = "Partial";
 293         else
 294                 authmsg = authenticated ? "Accepted" : "Failed";
 295
 296         authlog("%s %s%s%s for %s%.100s from %.200s port %d %s%s%s",
 297             authmsg,
 298             method,
 299             submethod != NULL ? "/" : "", submethod == NULL ? "" : submethod,
 300             authctxt->valid ? "" : "invalid user ",
 301             authctxt->user,
 302             get_remote_ipaddr(),
 303             get_remote_port(),
 304             compat20 ? "ssh2" : "ssh1",
 305             authctxt->info != NULL ? ": " : "",
 306             authctxt->info != NULL ? authctxt->info : "");
 307         free(authctxt->info);
 308         authctxt->info = NULL;
 309
 310 #ifdef CUSTOM_FAILED_LOGIN
 311         if (authenticated == 0 && !authctxt->postponed &&
 312             (strcmp(method, "password") == 0 ||
 313             strncmp(method, "keyboard-interactive", 20) == 0 ||
 314             strcmp(method, "challenge-response") == 0))
 315                 record_failed_login(authctxt->user,
 316                     get_canonical_hostname(options.use_dns), "ssh");
 317 # ifdef WITH_AIXAUTHENTICATE
 318         if (authenticated)
 319                 sys_auth_record_login(authctxt->user,
 320                     get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
 321 # endif
 322 #endif
 323 #ifdef SSH_AUDIT_EVENTS
 324         if (authenticated == 0 && !authctxt->postponed)
 325                 audit_event(audit_classify_auth(method));
 326 #endif
 327 }
 328
 329
 330 void
 331 auth_maxtries_exceeded(Authctxt *authctxt)
 332 {
 333         packet_disconnect("Too many authentication failures for "
 334             "%s%.100s from %.200s port %d %s",
 335             authctxt->valid ? "" : "invalid user ",
 336             authctxt->user,
 337             get_remote_ipaddr(),
 338             get_remote_port(),
 339             compat20 ? "ssh2" : "ssh1");
 340         /* NOTREACHED */
 341 }
 342
 343 /*
 344  * Check whether root logins are disallowed.
 345  */
 346 int
 347 auth_root_allowed(const char *method)
 348 {
 349         switch (options.permit_root_login) {
 350         case PERMIT_YES:
 351                 return 1;
 352         case PERMIT_NO_PASSWD:
 353                 if (strcmp(method, "password") != 0)
 354                         return 1;
 355                 break;
 356         case PERMIT_FORCED_ONLY:
 357                 if (forced_command) {
 358                         logit("Root login accepted for forced command.");
 359                         return 1;
 360                 }
 361                 break;
 362         }
 363         logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
 364         return 0;
 365 }
 366
 367
 368 /*
 369  * Given a template and a passwd structure, build a filename
 370  * by substituting % tokenised options. Currently, %% becomes '%',
 371  * %h becomes the home directory and %u the username.
 372  *
 373  * This returns a buffer allocated by xmalloc.
 374  */
 375 char *
 376 expand_authorized_keys(const char *filename, struct passwd *pw)
 377 {
 378         char *file, ret[MAXPATHLEN];
 379         int i;
 380
 381         file = percent_expand(filename, "h", pw->pw_dir,
 382             "u", pw->pw_name, (char *)NULL);
 383
 384         /*
 385          * Ensure that filename starts anchored. If not, be backward
 386          * compatible and prepend the '%h/'
 387          */
 388         if (*file == '/')
 389                 return (file);
 390
 391         i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
 392         if (i < 0 || (size_t)i >= sizeof(ret))
 393                 fatal("expand_authorized_keys: path too long");
 394         free(file);
 395         return (xstrdup(ret));
 396 }
 397
 398 char *
 399 authorized_principals_file(struct passwd *pw)
 400 {
 401         if (options.authorized_principals_file == NULL ||
 402             strcasecmp(options.authorized_principals_file, "none") == 0)
 403                 return NULL;
 404         return expand_authorized_keys(options.authorized_principals_file, pw);
 405 }
 406
 407 /* return ok if key exists in sysfile or userfile */
 408 HostStatus
 409 check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
 410     const char *sysfile, const char *userfile)
 411 {
 412         char *user_hostfile;
 413         struct stat st;
 414         HostStatus host_status;
 415         struct hostkeys *hostkeys;
 416         const struct hostkey_entry *found;
 417
 418         hostkeys = init_hostkeys();
 419         load_hostkeys(hostkeys, host, sysfile);
 420         if (userfile != NULL) {
 421                 user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
 422                 if (options.strict_modes &&
 423                     (stat(user_hostfile, &st) == 0) &&
 424                     ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
 425                     (st.st_mode & 022) != 0)) {
 426                         logit("Authentication refused for %.100s: "
 427                             "bad owner or modes for %.200s",
 428                             pw->pw_name, user_hostfile);
 429                         auth_debug_add("Ignored %.200s: bad ownership or modes",
 430                             user_hostfile);
 431                 } else {
 432                         temporarily_use_uid(pw);
 433                         load_hostkeys(hostkeys, host, user_hostfile);
 434                         restore_uid();
 435                 }
 436                 free(user_hostfile);
 437         }
 438         host_status = check_key_in_hostkeys(hostkeys, key, &found);
 439         if (host_status == HOST_REVOKED)
 440                 error("WARNING: revoked key for %s attempted authentication",
 441                     found->host);
 442         else if (host_status == HOST_OK)
 443                 debug("%s: key for %s found at %s:%ld", __func__,
 444                     found->host, found->file, found->line);
 445         else
 446                 debug("%s: key for host %s not found", __func__, host);
 447
 448         free_hostkeys(hostkeys);
 449
 450         return host_status;
 451 }
 452
 453 /*
 454  * Check a given path for security. This is defined as all components
 455  * of the path to the file must be owned by either the owner of
 456  * of the file or root and no directories must be group or world writable.
 457  *
 458  * XXX Should any specific check be done for sym links ?
 459  *
 460  * Takes a file name, its stat information (preferably from fstat() to
 461  * avoid races), the uid of the expected owner, their home directory and an
 462  * error buffer plus max size as arguments.
 463  *
 464  * Returns 0 on success and -1 on failure
 465  */
 466 int
 467 auth_secure_path(const char *name, struct stat *stp, const char *pw_dir,
 468     uid_t uid, char *err, size_t errlen)
 469 {
 470         char buf[MAXPATHLEN], homedir[MAXPATHLEN];
 471         char *cp;
 472         int comparehome = 0;
 473         struct stat st;
 474
 475         if (realpath(name, buf) == NULL) {
 476                 snprintf(err, errlen, "realpath %s failed: %s", name,
 477                     strerror(errno));
 478                 return -1;
 479         }
 480         if (pw_dir != NULL && realpath(pw_dir, homedir) != NULL)
 481                 comparehome = 1;
 482
 483         if (!S_ISREG(stp->st_mode)) {
 484                 snprintf(err, errlen, "%s is not a regular file", buf);
 485                 return -1;
 486         }
 487         if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) ||
 488             (stp->st_mode & 022) != 0) {
 489                 snprintf(err, errlen, "bad ownership or modes for file %s",
 490                     buf);
 491                 return -1;
 492         }
 493
 494         /* for each component of the canonical path, walking upwards */
 495         for (;;) {
 496                 if ((cp = dirname(buf)) == NULL) {
 497                         snprintf(err, errlen, "dirname() failed");
 498                         return -1;
 499                 }
 500                 strlcpy(buf, cp, sizeof(buf));
 501
 502                 if (stat(buf, &st) < 0 ||
 503                     (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) ||
 504                     (st.st_mode & 022) != 0) {
 505                         snprintf(err, errlen,
 506                             "bad ownership or modes for directory %s", buf);
 507                         return -1;
 508                 }
 509
 510                 /* If are past the homedir then we can stop */
 511                 if (comparehome && strcmp(homedir, buf) == 0)
 512                         break;
 513
 514                 /*
 515                  * dirname should always complete with a "/" path,
 516                  * but we can be paranoid and check for "." too
 517                  */
 518                 if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
 519                         break;
 520         }
 521         return 0;
 522 }
 523
 524 /*
 525  * Version of secure_path() that accepts an open file descriptor to
 526  * avoid races.
 527  *
 528  * Returns 0 on success and -1 on failure
 529  */
 530 static int
 531 secure_filename(FILE *f, const char *file, struct passwd *pw,
 532     char *err, size_t errlen)
 533 {
 534         struct stat st;
 535
 536         /* check the open file to avoid races */
 537         if (fstat(fileno(f), &st) < 0) {
 538                 snprintf(err, errlen, "cannot stat file %s: %s",
 539                     file, strerror(errno));
 540                 return -1;
 541         }
 542         return auth_secure_path(file, &st, pw->pw_dir, pw->pw_uid, err, errlen);
 543 }
 544
 545 static FILE *
 546 auth_openfile(const char *file, struct passwd *pw, int strict_modes,
 547     int log_missing, char *file_type)
 548 {
 549         char line[1024];
 550         struct stat st;
 551         int fd;
 552         FILE *f;
 553
 554         if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1) {
 555                 if (log_missing || errno != ENOENT)
 556                         debug("Could not open %s '%s': %s", file_type, file,
 557                            strerror(errno));
 558                 return NULL;
 559         }
 560
 561         if (fstat(fd, &st) < 0) {
 562                 close(fd);
 563                 return NULL;
 564         }
 565         if (!S_ISREG(st.st_mode)) {
 566                 logit("User %s %s %s is not a regular file",
 567                     pw->pw_name, file_type, file);
 568                 close(fd);
 569                 return NULL;
 570         }
 571         unset_nonblock(fd);
 572         if ((f = fdopen(fd, "r")) == NULL) {
 573                 close(fd);
 574                 return NULL;
 575         }
 576         if (strict_modes &&
 577             secure_filename(f, file, pw, line, sizeof(line)) != 0) {
 578                 fclose(f);
 579                 logit("Authentication refused: %s", line);
 580                 auth_debug_add("Ignored %s: %s", file_type, line);
 581                 return NULL;
 582         }
 583
 584         return f;
 585 }
 586
 587
 588 FILE *
 589 auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
 590 {
 591         return auth_openfile(file, pw, strict_modes, 1, "authorized keys");
 592 }
 593
 594 FILE *
 595 auth_openprincipals(const char *file, struct passwd *pw, int strict_modes)
 596 {
 597         return auth_openfile(file, pw, strict_modes, 0,
 598             "authorized principals");
 599 }
 600
 601 struct passwd *
 602 getpwnamallow(const char *user)
 603 {
 604 #ifdef HAVE_LOGIN_CAP
 605         extern login_cap_t *lc;
 606 #ifdef BSD_AUTH
 607         auth_session_t *as;
 608 #endif
 609 #endif
 610         struct passwd *pw;
 611         struct connection_info *ci = get_connection_info(1, options.use_dns);
 612
 613         ci->user = user;
 614         parse_server_match_config(&options, ci);
 615
 616 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
 617         aix_setauthdb(user);
 618 #endif
 619
 620         pw = getpwnam(user);
 621
 622 #if defined(_AIX) && defined(HAVE_SETAUTHDB)
 623         aix_restoreauthdb();
 624 #endif
 625 #ifdef HAVE_CYGWIN
 626         /*
 627          * Windows usernames are case-insensitive.  To avoid later problems
 628          * when trying to match the username, the user is only allowed to
 629          * login if the username is given in the same case as stored in the
 630          * user database.
 631          */
 632         if (pw != NULL && strcmp(user, pw->pw_name) != 0) {
 633                 logit("Login name %.100s does not match stored username %.100s",
 634                     user, pw->pw_name);
 635                 pw = NULL;
 636         }
 637 #endif
 638         if (pw == NULL) {
 639                 logit("Invalid user %.100s from %.100s",
 640                     user, get_remote_ipaddr());
 641 #ifdef CUSTOM_FAILED_LOGIN
 642                 record_failed_login(user,
 643                     get_canonical_hostname(options.use_dns), "ssh");
 644 #endif
 645 #ifdef SSH_AUDIT_EVENTS
 646                 audit_event(SSH_INVALID_USER);
 647 #endif /* SSH_AUDIT_EVENTS */
 648                 return (NULL);
 649         }
 650         if (!allowed_user(pw))
 651                 return (NULL);
 652 #ifdef HAVE_LOGIN_CAP
 653         if ((lc = login_getclass(pw->pw_class)) == NULL) {
 654                 debug("unable to get login class: %s", user);
 655                 return (NULL);
 656         }
 657 #ifdef BSD_AUTH
 658         if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
 659             auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
 660                 debug("Approval failure for %s", user);
 661                 pw = NULL;
 662         }
 663         if (as != NULL)
 664                 auth_close(as);
 665 #endif
 666 #endif
 667         if (pw != NULL)
 668                 return (pwcopy(pw));
 669         return (NULL);
 670 }
 671
 672 /* Returns 1 if key is revoked by revoked_keys_file, 0 otherwise */
 673 int
 674 auth_key_is_revoked(Key *key)
 675 {
 676 #ifdef WITH_OPENSSL
 677         char *key_fp;
 678
 679         if (options.revoked_keys_file == NULL)
 680                 return 0;
 681         switch (ssh_krl_file_contains_key(options.revoked_keys_file, key)) {
 682         case 0:
 683                 return 0;       /* Not revoked */
 684         case -2:
 685                 break;          /* Not a KRL */
 686         default:
 687                 goto revoked;
 688         }
 689 #endif
 690         debug3("%s: treating %s as a key list", __func__,
 691             options.revoked_keys_file);
 692         switch (key_in_file(key, options.revoked_keys_file, 0)) {
 693         case 0:
 694                 /* key not revoked */
 695                 return 0;
 696         case -1:
 697                 /* Error opening revoked_keys_file: refuse all keys */
 698                 error("Revoked keys file is unreadable: refusing public key "
 699                     "authentication");
 700                 return 1;
 701 #ifdef WITH_OPENSSL
 702         case 1:
 703  revoked:
 704                 /* Key revoked */
 705                 key_fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX);
 706                 error("WARNING: authentication attempt with a revoked "
 707                     "%s key %s ", key_type(key), key_fp);
 708                 free(key_fp);
 709                 return 1;
 710 #endif
 711         }
 712         fatal("key_in_file returned junk");
 713 }
 714
 715 void
 716 auth_debug_add(const char *fmt,...)
 717 {
 718         char buf[1024];
 719         va_list args;
 720
 721         if (!auth_debug_init)
 722                 return;
 723
 724         va_start(args, fmt);
 725         vsnprintf(buf, sizeof(buf), fmt, args);
 726         va_end(args);
 727         buffer_put_cstring(&auth_debug, buf);
 728 }
 729
 730 void
 731 auth_debug_send(void)
 732 {
 733         char *msg;
 734
 735         if (!auth_debug_init)
 736                 return;
 737         while (buffer_len(&auth_debug)) {
 738                 msg = buffer_get_string(&auth_debug, NULL);
 739                 packet_send_debug("%s", msg);
 740                 free(msg);
 741         }
 742 }
 743
 744 void
 745 auth_debug_reset(void)
 746 {
 747         if (auth_debug_init)
 748                 buffer_clear(&auth_debug);
 749         else {
 750                 buffer_init(&auth_debug);
 751                 auth_debug_init = 1;
 752         }
 753 }
 754
 755 struct passwd *
 756 fakepw(void)
 757 {
 758         static struct passwd fake;
 759
 760         memset(&fake, 0, sizeof(fake));
 761         fake.pw_name = "NOUSER";
 762         fake.pw_passwd =
 763             "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
 764 #ifdef HAVE_STRUCT_PASSWD_PW_GECOS
 765         fake.pw_gecos = "NOUSER";
 766 #endif
 767         fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
 768         fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
 769 #ifdef HAVE_STRUCT_PASSWD_PW_CLASS
 770         fake.pw_class = "";
 771 #endif
 772         fake.pw_dir = "/nonexist";
 773         fake.pw_shell = "/nonexist";
 774
 775         return (&fake);
 776 }