granicus.if.org Git - linux-pam/blob - modules/pam_unix/pam_unix_passwd.c

   1 /*
   2  * Main coding by Elliot Lee <sopwith@redhat.com>, Red Hat Software.
   3  * Copyright (C) 1996.
   4  * Copyright (c) Jan Rêkorajski, 1999.
   5  * Copyright (c) Red Hat, Inc., 2007, 2008.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, and the entire permission notice in its entirety,
  12  *    including the disclaimer of warranties.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 3. The name of the author may not be used to endorse or promote
  17  *    products derived from this software without specific prior
  18  *    written permission.
  19  *
  20  * ALTERNATIVELY, this product may be distributed under the terms of
  21  * the GNU Public License, in which case the provisions of the GPL are
  22  * required INSTEAD OF the above restrictions.  (This clause is
  23  * necessary due to a potential bad interaction between the GPL and
  24  * the restrictions contained in a BSD-style copyright.)
  25  *
  26  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
  27  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  28  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  29  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  30  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  31  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  32  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  34  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
  36  * OF THE POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 #include "config.h"
  40
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <stdarg.h>
  44 #include <string.h>
  45 #include <malloc.h>
  46 #include <unistd.h>
  47 #include <errno.h>
  48 #include <sys/types.h>
  49 #include <pwd.h>
  50 #include <syslog.h>
  51 #include <shadow.h>
  52 #include <time.h>               /* for time() */
  53 #include <fcntl.h>
  54 #include <ctype.h>
  55 #include <sys/time.h>
  56 #include <sys/stat.h>
  57 #include <rpc/rpc.h>
  58 #include <rpcsvc/yp_prot.h>
  59 #include <rpcsvc/ypclnt.h>
  60
  61 #include <signal.h>
  62 #include <errno.h>
  63 #include <sys/wait.h>
  64 #ifdef WITH_SELINUX
  65 static int selinux_enabled=-1;
  66 #include <selinux/selinux.h>
  67 #define SELINUX_ENABLED (selinux_enabled!=-1 ? selinux_enabled : (selinux_enabled=is_selinux_enabled()>0))
  68 #endif
  69
  70 #include <security/_pam_macros.h>
  71
  72 /* indicate the following groups are defined */
  73
  74 #define PAM_SM_PASSWORD
  75
  76 #include <security/pam_modules.h>
  77 #include <security/pam_ext.h>
  78 #include <security/pam_modutil.h>
  79
  80 #include "yppasswd.h"
  81 #include "md5.h"
  82 #include "support.h"
  83 #include "passverify.h"
  84 #include "bigcrypt.h"
  85
  86 #if !((__GLIBC__ == 2) && (__GLIBC_MINOR__ >= 1))
  87 extern int getrpcport(const char *host, unsigned long prognum,
  88                       unsigned long versnum, unsigned int proto);
  89 #endif                          /* GNU libc 2.1 */
  90
  91 /*
  92    How it works:
  93    Gets in username (has to be done) from the calling program
  94    Does authentication of user (only if we are not running as root)
  95    Gets new password/checks for sanity
  96    Sets it.
  97  */
  98
  99 /* data tokens */
 100
 101 #define _UNIX_OLD_AUTHTOK       "-UN*X-OLD-PASS"
 102 #define _UNIX_NEW_AUTHTOK       "-UN*X-NEW-PASS"
 103
 104 #define MAX_PASSWD_TRIES        3
 105
 106 static char *getNISserver(pam_handle_t *pamh)
 107 {
 108         char *master;
 109         char *domainname;
 110         int port, err;
 111
 112         if ((err = yp_get_default_domain(&domainname)) != 0) {
 113                 pam_syslog(pamh, LOG_WARNING, "can't get local yp domain: %s",
 114                          yperr_string(err));
 115                 return NULL;
 116         }
 117         if ((err = yp_master(domainname, "passwd.byname", &master)) != 0) {
 118                 pam_syslog(pamh, LOG_WARNING, "can't find the master ypserver: %s",
 119                          yperr_string(err));
 120                 return NULL;
 121         }
 122         port = getrpcport(master, YPPASSWDPROG, YPPASSWDPROC_UPDATE, IPPROTO_UDP);
 123         if (port == 0) {
 124                 pam_syslog(pamh, LOG_WARNING,
 125                          "yppasswdd not running on NIS master host");
 126                 return NULL;
 127         }
 128         if (port >= IPPORT_RESERVED) {
 129                 pam_syslog(pamh, LOG_WARNING,
 130                          "yppasswd daemon running on illegal port");
 131                 return NULL;
 132         }
 133         return master;
 134 }
 135
 136 #ifdef WITH_SELINUX
 137
 138 static int _unix_run_update_binary(pam_handle_t *pamh, unsigned int ctrl, const char *user,
 139     const char *fromwhat, const char *towhat, int remember)
 140 {
 141     int retval, child, fds[2];
 142     void (*sighandler)(int) = NULL;
 143
 144     D(("called."));
 145     /* create a pipe for the password */
 146     if (pipe(fds) != 0) {
 147         D(("could not make pipe"));
 148         return PAM_AUTH_ERR;
 149     }
 150
 151     if (off(UNIX_NOREAP, ctrl)) {
 152         /*
 153          * This code arranges that the demise of the child does not cause
 154          * the application to receive a signal it is not expecting - which
 155          * may kill the application or worse.
 156          *
 157          * The "noreap" module argument is provided so that the admin can
 158          * override this behavior.
 159          */
 160         sighandler = signal(SIGCHLD, SIG_DFL);
 161     }
 162
 163     /* fork */
 164     child = fork();
 165     if (child == 0) {
 166         int i=0;
 167         struct rlimit rlim;
 168         static char *envp[] = { NULL };
 169         char *args[] = { NULL, NULL, NULL, NULL, NULL, NULL };
 170         char buffer[16];
 171
 172         /* XXX - should really tidy up PAM here too */
 173
 174         /* reopen stdin as pipe */
 175         dup2(fds[0], STDIN_FILENO);
 176
 177         if (getrlimit(RLIMIT_NOFILE,&rlim)==0) {
 178           if (rlim.rlim_max >= MAX_FD_NO)
 179             rlim.rlim_max = MAX_FD_NO;
 180           for (i=0; i < (int)rlim.rlim_max; i++) {
 181             if (i != STDIN_FILENO)
 182                    close(i);
 183           }
 184         }
 185
 186         if (SELINUX_ENABLED && geteuid() == 0) {
 187           /* must set the real uid to 0 so the helper will not error
 188              out if pam is called from setuid binary (su, sudo...) */
 189           setuid(0);
 190         }
 191
 192         /* exec binary helper */
 193         args[0] = x_strdup(UPDATE_HELPER);
 194         args[1] = x_strdup(user);
 195         args[2] = x_strdup("update");
 196         if (on(UNIX_SHADOW, ctrl))
 197                 args[3] = x_strdup("1");
 198         else
 199                 args[3] = x_strdup("0");
 200
 201         snprintf(buffer, sizeof(buffer), "%d", remember);
 202         args[4] = x_strdup(buffer);
 203
 204         execve(UPDATE_HELPER, args, envp);
 205
 206         /* should not get here: exit with error */
 207         D(("helper binary is not available"));
 208         exit(PAM_AUTHINFO_UNAVAIL);
 209     } else if (child > 0) {
 210         /* wait for child */
 211         /* if the stored password is NULL */
 212         int rc=0;
 213         if (fromwhat)
 214           pam_modutil_write(fds[1], fromwhat, strlen(fromwhat)+1);
 215         else
 216           pam_modutil_write(fds[1], "", 1);
 217         if (towhat) {
 218           pam_modutil_write(fds[1], towhat, strlen(towhat)+1);
 219         }
 220         else
 221           pam_modutil_write(fds[1], "", 1);
 222
 223         close(fds[0]);       /* close here to avoid possible SIGPIPE above */
 224         close(fds[1]);
 225         rc=waitpid(child, &retval, 0);  /* wait for helper to complete */
 226         if (rc<0) {
 227           pam_syslog(pamh, LOG_ERR, "unix_update waitpid failed: %m");
 228           retval = PAM_AUTH_ERR;
 229         } else {
 230           retval = WEXITSTATUS(retval);
 231         }
 232     } else {
 233         D(("fork failed"));
 234         close(fds[0]);
 235         close(fds[1]);
 236         retval = PAM_AUTH_ERR;
 237     }
 238
 239     if (sighandler != SIG_ERR) {
 240         (void) signal(SIGCHLD, sighandler);   /* restore old signal handler */
 241     }
 242
 243     return retval;
 244 }
 245 #endif
 246
 247 static int check_old_password(const char *forwho, const char *newpass)
 248 {
 249         static char buf[16384];
 250         char *s_luser, *s_uid, *s_npas, *s_pas;
 251         int retval = PAM_SUCCESS;
 252         FILE *opwfile;
 253
 254         opwfile = fopen(OLD_PASSWORDS_FILE, "r");
 255         if (opwfile == NULL)
 256                 return PAM_ABORT;
 257
 258         while (fgets(buf, 16380, opwfile)) {
 259                 if (!strncmp(buf, forwho, strlen(forwho))) {
 260                         char *sptr;
 261                         buf[strlen(buf) - 1] = '\0';
 262                         s_luser = strtok_r(buf, ":,", &sptr);
 263                         s_uid = strtok_r(NULL, ":,", &sptr);
 264                         s_npas = strtok_r(NULL, ":,", &sptr);
 265                         s_pas = strtok_r(NULL, ":,", &sptr);
 266                         while (s_pas != NULL) {
 267                                 char *md5pass = Goodcrypt_md5(newpass, s_pas);
 268                                 if (!strcmp(md5pass, s_pas)) {
 269                                         _pam_delete(md5pass);
 270                                         retval = PAM_AUTHTOK_ERR;
 271                                         break;
 272                                 }
 273                                 s_pas = strtok_r(NULL, ":,", &sptr);
 274                                 _pam_delete(md5pass);
 275                         }
 276                         break;
 277                 }
 278         }
 279         fclose(opwfile);
 280
 281         return retval;
 282 }
 283
 284 static int _do_setpass(pam_handle_t* pamh, const char *forwho,
 285                        const char *fromwhat,
 286                        char *towhat, unsigned int ctrl, int remember)
 287 {
 288         struct passwd *pwd = NULL;
 289         int retval = 0;
 290         int unlocked = 0;
 291         char *master = NULL;
 292
 293         D(("called"));
 294
 295         pwd = getpwnam(forwho);
 296
 297         if (pwd == NULL) {
 298                 retval = PAM_AUTHTOK_ERR;
 299                 goto done;
 300         }
 301
 302         if (on(UNIX_NIS, ctrl) && _unix_comesfromsource(pamh, forwho, 0, 1)) {
 303             if ((master=getNISserver(pamh)) != NULL) {
 304                 struct timeval timeout;
 305                 struct yppasswd yppwd;
 306                 CLIENT *clnt;
 307                 int status;
 308                 enum clnt_stat err;
 309
 310                 /* Unlock passwd file to avoid deadlock */
 311                 unlock_pwdf();
 312                 unlocked = 1;
 313
 314                 /* Initialize password information */
 315                 yppwd.newpw.pw_passwd = pwd->pw_passwd;
 316                 yppwd.newpw.pw_name = pwd->pw_name;
 317                 yppwd.newpw.pw_uid = pwd->pw_uid;
 318                 yppwd.newpw.pw_gid = pwd->pw_gid;
 319                 yppwd.newpw.pw_gecos = pwd->pw_gecos;
 320                 yppwd.newpw.pw_dir = pwd->pw_dir;
 321                 yppwd.newpw.pw_shell = pwd->pw_shell;
 322                 yppwd.oldpass = fromwhat ? strdup (fromwhat) : strdup ("");
 323                 yppwd.newpw.pw_passwd = towhat;
 324
 325                 D(("Set password %s for %s", yppwd.newpw.pw_passwd, forwho));
 326
 327                 /* The yppasswd.x file said `unix authentication required',
 328                  * so I added it. This is the only reason it is in here.
 329                  * My yppasswdd doesn't use it, but maybe some others out there
 330                  * do.                                        --okir
 331                  */
 332                 clnt = clnt_create(master, YPPASSWDPROG, YPPASSWDVERS, "udp");
 333                 clnt->cl_auth = authunix_create_default();
 334                 memset((char *) &status, '\0', sizeof(status));
 335                 timeout.tv_sec = 25;
 336                 timeout.tv_usec = 0;
 337                 err = clnt_call(clnt, YPPASSWDPROC_UPDATE,
 338                                 (xdrproc_t) xdr_yppasswd, (char *) &yppwd,
 339                                 (xdrproc_t) xdr_int, (char *) &status,
 340                                 timeout);
 341
 342                 free (yppwd.oldpass);
 343
 344                 if (err) {
 345                         _make_remark(pamh, ctrl, PAM_TEXT_INFO,
 346                                 clnt_sperrno(err));
 347                 } else if (status) {
 348                         D(("Error while changing NIS password.\n"));
 349                 }
 350                 D(("The password has%s been changed on %s.",
 351                    (err || status) ? " not" : "", master));
 352                 pam_syslog(pamh, LOG_NOTICE, "password%s changed for %s on %s",
 353                          (err || status) ? " not" : "", pwd->pw_name, master);
 354
 355                 auth_destroy(clnt->cl_auth);
 356                 clnt_destroy(clnt);
 357                 if (err || status) {
 358                         _make_remark(pamh, ctrl, PAM_TEXT_INFO,
 359                                 _("NIS password could not be changed."));
 360                         retval = PAM_TRY_AGAIN;
 361                 }
 362 #ifdef DEBUG
 363                 sleep(5);
 364 #endif
 365             } else {
 366                     retval = PAM_TRY_AGAIN;
 367             }
 368         }
 369
 370         if (_unix_comesfromsource(pamh, forwho, 1, 0)) {
 371                 if(unlocked) {
 372                         if (lock_pwdf() != PAM_SUCCESS) {
 373                                 return PAM_AUTHTOK_LOCK_BUSY;
 374                         }
 375                 }
 376 #ifdef WITH_SELINUX
 377                 if (unix_selinux_confined())
 378                           return _unix_run_update_binary(pamh, ctrl, forwho, fromwhat, towhat, remember);
 379 #endif
 380                 /* first, save old password */
 381                 if (save_old_password(pamh, forwho, fromwhat, remember)) {
 382                         retval = PAM_AUTHTOK_ERR;
 383                         goto done;
 384                 }
 385                 if (on(UNIX_SHADOW, ctrl) || is_pwd_shadowed(pwd)) {
 386                         retval = unix_update_shadow(pamh, forwho, towhat);
 387                         if (retval == PAM_SUCCESS)
 388                                 if (!is_pwd_shadowed(pwd))
 389                                         retval = unix_update_passwd(pamh, forwho, "x");
 390                 } else {
 391                         retval = unix_update_passwd(pamh, forwho, towhat);
 392                 }
 393         }
 394
 395
 396 done:
 397         unlock_pwdf();
 398
 399         return retval;
 400 }
 401
 402 static int _unix_verify_shadow(pam_handle_t *pamh, const char *user, unsigned int ctrl)
 403 {
 404         struct passwd *pwent = NULL;    /* Password and shadow password */
 405         struct spwd *spent = NULL;      /* file entries for the user */
 406         int daysleft;
 407         int retval;
 408
 409         retval = get_account_info(pamh, user, &pwent, &spent);
 410         if (retval == PAM_USER_UNKNOWN) {
 411                 return retval;
 412         }
 413
 414         if (retval == PAM_SUCCESS && spent == NULL)
 415                 return PAM_SUCCESS;
 416
 417         if (retval == PAM_UNIX_RUN_HELPER) {
 418                 retval = _unix_run_verify_binary(pamh, ctrl, user, &daysleft);
 419                 if (retval == PAM_AUTH_ERR || retval == PAM_USER_UNKNOWN)
 420                         return retval;
 421         }
 422         else if (retval == PAM_SUCCESS)
 423                 retval = check_shadow_expiry(pamh, spent, &daysleft);
 424
 425         if (on(UNIX__IAMROOT, ctrl) || retval == PAM_NEW_AUTHTOK_REQD)
 426                 return PAM_SUCCESS;
 427
 428         return retval;
 429 }
 430
 431 static int _pam_unix_approve_pass(pam_handle_t * pamh
 432                                   ,unsigned int ctrl
 433                                   ,const char *pass_old
 434                                   ,const char *pass_new)
 435 {
 436         const void *user;
 437         const char *remark = NULL;
 438         int retval = PAM_SUCCESS;
 439
 440         D(("&new=%p, &old=%p", pass_old, pass_new));
 441         D(("new=[%s]", pass_new));
 442         D(("old=[%s]", pass_old));
 443
 444         if (pass_new == NULL || (pass_old && !strcmp(pass_old, pass_new))) {
 445                 if (on(UNIX_DEBUG, ctrl)) {
 446                         pam_syslog(pamh, LOG_DEBUG, "bad authentication token");
 447                 }
 448                 _make_remark(pamh, ctrl, PAM_ERROR_MSG, pass_new == NULL ?
 449                         _("No password supplied") : _("Password unchanged"));
 450                 return PAM_AUTHTOK_ERR;
 451         }
 452         /*
 453          * if one wanted to hardwire authentication token strength
 454          * checking this would be the place - AGM
 455          */
 456
 457         retval = pam_get_item(pamh, PAM_USER, &user);
 458         if (retval != PAM_SUCCESS) {
 459                 if (on(UNIX_DEBUG, ctrl)) {
 460                         pam_syslog(pamh, LOG_ERR, "Can not get username");
 461                         return PAM_AUTHTOK_ERR;
 462                 }
 463         }
 464         if (off(UNIX__IAMROOT, ctrl)) {
 465                 if (strlen(pass_new) < 6)
 466                   remark = _("You must choose a longer password");
 467                 D(("length check [%s]", remark));
 468                 if (on(UNIX_REMEMBER_PASSWD, ctrl)) {
 469                         if ((retval = check_old_password(user, pass_new)) == PAM_AUTHTOK_ERR)
 470                           remark = _("Password has been already used. Choose another.");
 471                         if (retval == PAM_ABORT) {
 472                                 pam_syslog(pamh, LOG_ERR, "can't open %s file to check old passwords",
 473                                         OLD_PASSWORDS_FILE);
 474                                 return retval;
 475                         }
 476                 }
 477         }
 478         if (remark) {
 479                 _make_remark(pamh, ctrl, PAM_ERROR_MSG, remark);
 480                 retval = PAM_AUTHTOK_ERR;
 481         }
 482         return retval;
 483 }
 484
 485
 486 PAM_EXTERN int pam_sm_chauthtok(pam_handle_t * pamh, int flags,
 487                                 int argc, const char **argv)
 488 {
 489         unsigned int ctrl, lctrl;
 490         int retval;
 491         int remember = -1;
 492         int rounds = -1;
 493
 494         /* <DO NOT free() THESE> */
 495         const char *user;
 496         const void *pass_old, *pass_new;
 497         /* </DO NOT free() THESE> */
 498
 499         D(("called."));
 500
 501         ctrl = _set_ctrl(pamh, flags, &remember, &rounds, argc, argv);
 502
 503         /*
 504          * First get the name of a user
 505          */
 506         retval = pam_get_user(pamh, &user, NULL);
 507         if (retval == PAM_SUCCESS) {
 508                 /*
 509                  * Various libraries at various times have had bugs related to
 510                  * '+' or '-' as the first character of a user name. Don't
 511                  * allow them.
 512                  */
 513                 if (user == NULL || user[0] == '-' || user[0] == '+') {
 514                         pam_syslog(pamh, LOG_ERR, "bad username [%s]", user);
 515                         return PAM_USER_UNKNOWN;
 516                 }
 517                 if (retval == PAM_SUCCESS && on(UNIX_DEBUG, ctrl))
 518                         pam_syslog(pamh, LOG_DEBUG, "username [%s] obtained",
 519                                  user);
 520         } else {
 521                 if (on(UNIX_DEBUG, ctrl))
 522                         pam_syslog(pamh, LOG_DEBUG,
 523                                  "password - could not identify user");
 524                 return retval;
 525         }
 526
 527         D(("Got username of %s", user));
 528
 529         /*
 530          * Before we do anything else, check to make sure that the user's
 531          * info is in one of the databases we can modify from this module,
 532          * which currently is 'files' and 'nis'.  We have to do this because
 533          * getpwnam() doesn't tell you *where* the information it gives you
 534          * came from, nor should it.  That's our job.
 535          */
 536         if (_unix_comesfromsource(pamh, user, 1, on(UNIX_NIS, ctrl)) == 0) {
 537                 pam_syslog(pamh, LOG_DEBUG,
 538                          "user \"%s\" does not exist in /etc/passwd%s",
 539                          user, on(UNIX_NIS, ctrl) ? " or NIS" : "");
 540                 return PAM_USER_UNKNOWN;
 541         } else {
 542                 struct passwd *pwd;
 543                 _unix_getpwnam(pamh, user, 1, 1, &pwd);
 544                 if (pwd == NULL) {
 545                         pam_syslog(pamh, LOG_DEBUG,
 546                                 "user \"%s\" has corrupted passwd entry",
 547                                 user);
 548                         return PAM_USER_UNKNOWN;
 549                 }
 550         }
 551
 552         /*
 553          * This is not an AUTH module!
 554          */
 555         if (on(UNIX__NONULL, ctrl))
 556                 set(UNIX__NULLOK, ctrl);
 557
 558         if (on(UNIX__PRELIM, ctrl)) {
 559                 /*
 560                  * obtain and verify the current password (OLDAUTHTOK) for
 561                  * the user.
 562                  */
 563                 char *Announce;
 564
 565                 D(("prelim check"));
 566
 567                 if (_unix_blankpasswd(pamh, ctrl, user)) {
 568                         return PAM_SUCCESS;
 569                 } else if (off(UNIX__IAMROOT, ctrl)) {
 570                         /* instruct user what is happening */
 571                         if (asprintf(&Announce, _("Changing password for %s."),
 572                                 user) < 0) {
 573                                 pam_syslog(pamh, LOG_CRIT,
 574                                          "password - out of memory");
 575                                 return PAM_BUF_ERR;
 576                         }
 577
 578                         lctrl = ctrl;
 579                         set(UNIX__OLD_PASSWD, lctrl);
 580                         retval = _unix_read_password(pamh, lctrl
 581                                                      ,Announce
 582                                              ,_("(current) UNIX password: ")
 583                                                      ,NULL
 584                                                      ,_UNIX_OLD_AUTHTOK
 585                                              ,&pass_old);
 586                         free(Announce);
 587
 588                         if (retval != PAM_SUCCESS) {
 589                                 pam_syslog(pamh, LOG_NOTICE,
 590                                     "password - (old) token not obtained");
 591                                 return retval;
 592                         }
 593                         /* verify that this is the password for this user */
 594
 595                         retval = _unix_verify_password(pamh, user, pass_old, ctrl);
 596                 } else {
 597                         D(("process run by root so do nothing this time around"));
 598                         pass_old = NULL;
 599                         retval = PAM_SUCCESS;   /* root doesn't have too */
 600                 }
 601
 602                 if (retval != PAM_SUCCESS) {
 603                         D(("Authentication failed"));
 604                         pass_old = NULL;
 605                         return retval;
 606                 }
 607                 retval = pam_set_item(pamh, PAM_OLDAUTHTOK, (const void *) pass_old);
 608                 pass_old = NULL;
 609                 if (retval != PAM_SUCCESS) {
 610                         pam_syslog(pamh, LOG_CRIT,
 611                                  "failed to set PAM_OLDAUTHTOK");
 612                 }
 613                 retval = _unix_verify_shadow(pamh,user, ctrl);
 614                 if (retval == PAM_AUTHTOK_ERR) {
 615                         if (off(UNIX__IAMROOT, ctrl))
 616                                 _make_remark(pamh, ctrl, PAM_ERROR_MSG,
 617                                              _("You must wait longer to change your password"));
 618                         else
 619                                 retval = PAM_SUCCESS;
 620                 }
 621         } else if (on(UNIX__UPDATE, ctrl)) {
 622                 /*
 623                  * tpass is used below to store the _pam_md() return; it
 624                  * should be _pam_delete()'d.
 625                  */
 626
 627                 char *tpass = NULL;
 628                 int retry = 0;
 629
 630                 /*
 631                  * obtain the proposed password
 632                  */
 633
 634                 D(("do update"));
 635
 636                 /*
 637                  * get the old token back. NULL was ok only if root [at this
 638                  * point we assume that this has already been enforced on a
 639                  * previous call to this function].
 640                  */
 641
 642                 if (off(UNIX_NOT_SET_PASS, ctrl)) {
 643                         retval = pam_get_item(pamh, PAM_OLDAUTHTOK
 644                                               ,&pass_old);
 645                 } else {
 646                         retval = pam_get_data(pamh, _UNIX_OLD_AUTHTOK
 647                                               ,&pass_old);
 648                         if (retval == PAM_NO_MODULE_DATA) {
 649                                 retval = PAM_SUCCESS;
 650                                 pass_old = NULL;
 651                         }
 652                 }
 653                 D(("pass_old [%s]", pass_old));
 654
 655                 if (retval != PAM_SUCCESS) {
 656                         pam_syslog(pamh, LOG_NOTICE, "user not authenticated");
 657                         return retval;
 658                 }
 659
 660                 D(("get new password now"));
 661
 662                 lctrl = ctrl;
 663
 664                 if (on(UNIX_USE_AUTHTOK, lctrl)) {
 665                         set(UNIX_USE_FIRST_PASS, lctrl);
 666                 }
 667                 retry = 0;
 668                 retval = PAM_AUTHTOK_ERR;
 669                 while ((retval != PAM_SUCCESS) && (retry++ < MAX_PASSWD_TRIES)) {
 670                         /*
 671                          * use_authtok is to force the use of a previously entered
 672                          * password -- needed for pluggable password strength checking
 673                          */
 674
 675                         retval = _unix_read_password(pamh, lctrl
 676                                                      ,NULL
 677                                              ,_("Enter new UNIX password: ")
 678                                             ,_("Retype new UNIX password: ")
 679                                                      ,_UNIX_NEW_AUTHTOK
 680                                              ,&pass_new);
 681
 682                         if (retval != PAM_SUCCESS) {
 683                                 if (on(UNIX_DEBUG, ctrl)) {
 684                                         pam_syslog(pamh, LOG_ALERT,
 685                                                  "password - new password not obtained");
 686                                 }
 687                                 pass_old = NULL;        /* tidy up */
 688                                 return retval;
 689                         }
 690                         D(("returned to _unix_chauthtok"));
 691
 692                         /*
 693                          * At this point we know who the user is and what they
 694                          * propose as their new password. Verify that the new
 695                          * password is acceptable.
 696                          */
 697
 698                         if (*(const char *)pass_new == '\0') {  /* "\0" password = NULL */
 699                                 pass_new = NULL;
 700                         }
 701                         retval = _pam_unix_approve_pass(pamh, ctrl, pass_old, pass_new);
 702
 703                         if (retval != PAM_SUCCESS && off(UNIX_NOT_SET_PASS, ctrl)) {
 704                                 pam_set_item(pamh, PAM_AUTHTOK, NULL);
 705                         }
 706                 }
 707
 708                 if (retval != PAM_SUCCESS) {
 709                         pam_syslog(pamh, LOG_NOTICE,
 710                                  "new password not acceptable");
 711                         pass_new = pass_old = NULL;     /* tidy up */
 712                         return retval;
 713                 }
 714                 if (lock_pwdf() != PAM_SUCCESS) {
 715                         return PAM_AUTHTOK_LOCK_BUSY;
 716                 }
 717
 718                 if (pass_old) {
 719                         retval = _unix_verify_password(pamh, user, pass_old, ctrl);
 720                         if (retval != PAM_SUCCESS) {
 721                                 pam_syslog(pamh, LOG_NOTICE, "user password changed by another process");
 722                                 unlock_pwdf();
 723                                 return retval;
 724                         }
 725                 }
 726
 727                 retval = _unix_verify_shadow(pamh, user, ctrl);
 728                 if (retval != PAM_SUCCESS) {
 729                         pam_syslog(pamh, LOG_NOTICE, "user shadow entry expired");
 730                         unlock_pwdf();
 731                         return retval;
 732                 }
 733
 734                 retval = _pam_unix_approve_pass(pamh, ctrl, pass_old, pass_new);
 735                 if (retval != PAM_SUCCESS) {
 736                         pam_syslog(pamh, LOG_NOTICE,
 737                                  "new password not acceptable 2");
 738                         pass_new = pass_old = NULL;     /* tidy up */
 739                         unlock_pwdf();
 740                         return retval;
 741                 }
 742
 743                 /*
 744                  * By reaching here we have approved the passwords and must now
 745                  * rebuild the password database file.
 746                  */
 747
 748                 /*
 749                  * First we encrypt the new password.
 750                  */
 751
 752                 tpass = create_password_hash(pass_new, ctrl, rounds);
 753                 if (tpass == NULL) {
 754                         pam_syslog(pamh, LOG_CRIT,
 755                                 "out of memory for password");
 756                         pass_new = pass_old = NULL;     /* tidy up */
 757                         unlock_pwdf();
 758                         return PAM_BUF_ERR;
 759                 }
 760
 761                 D(("password processed"));
 762
 763                 /* update the password database(s) -- race conditions..? */
 764
 765                 retval = _do_setpass(pamh, user, pass_old, tpass, ctrl,
 766                                      remember);
 767                 /* _do_setpass has called unlock_pwdf for us */
 768
 769                 _pam_delete(tpass);
 770                 pass_old = pass_new = NULL;
 771         } else {                /* something has broken with the module */
 772                 pam_syslog(pamh, LOG_ALERT,
 773                          "password received unknown request");
 774                 retval = PAM_ABORT;
 775         }
 776
 777         D(("retval was %d", retval));
 778
 779         return retval;
 780 }
 781
 782
 783 /* static module data */
 784 #ifdef PAM_STATIC
 785 struct pam_module _pam_unix_passwd_modstruct = {
 786     "pam_unix_passwd",
 787     NULL,
 788     NULL,
 789     NULL,
 790     NULL,
 791     NULL,
 792     pam_sm_chauthtok,
 793 };
 794 #endif