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     struct sigaction newsa, oldsa;
 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         memset(&newsa, '\0', sizeof(newsa));
 161         newsa.sa_handler = SIG_DFL;
 162         sigaction(SIGCHLD, &newsa, &oldsa);
 163     }
 164
 165     /* fork */
 166     child = fork();
 167     if (child == 0) {
 168         int i=0;
 169         struct rlimit rlim;
 170         static char *envp[] = { NULL };
 171         char *args[] = { NULL, NULL, NULL, NULL, NULL, NULL };
 172         char buffer[16];
 173
 174         /* XXX - should really tidy up PAM here too */
 175
 176         /* reopen stdin as pipe */
 177         dup2(fds[0], STDIN_FILENO);
 178
 179         if (getrlimit(RLIMIT_NOFILE,&rlim)==0) {
 180           if (rlim.rlim_max >= MAX_FD_NO)
 181             rlim.rlim_max = MAX_FD_NO;
 182           for (i=0; i < (int)rlim.rlim_max; i++) {
 183             if (i != STDIN_FILENO)
 184                    close(i);
 185           }
 186         }
 187
 188         if (SELINUX_ENABLED && geteuid() == 0) {
 189           /* must set the real uid to 0 so the helper will not error
 190              out if pam is called from setuid binary (su, sudo...) */
 191           setuid(0);
 192         }
 193
 194         /* exec binary helper */
 195         args[0] = x_strdup(UPDATE_HELPER);
 196         args[1] = x_strdup(user);
 197         args[2] = x_strdup("update");
 198         if (on(UNIX_SHADOW, ctrl))
 199                 args[3] = x_strdup("1");
 200         else
 201                 args[3] = x_strdup("0");
 202
 203         snprintf(buffer, sizeof(buffer), "%d", remember);
 204         args[4] = x_strdup(buffer);
 205
 206         execve(UPDATE_HELPER, args, envp);
 207
 208         /* should not get here: exit with error */
 209         D(("helper binary is not available"));
 210         exit(PAM_AUTHINFO_UNAVAIL);
 211     } else if (child > 0) {
 212         /* wait for child */
 213         /* if the stored password is NULL */
 214         int rc=0;
 215         if (fromwhat)
 216           pam_modutil_write(fds[1], fromwhat, strlen(fromwhat)+1);
 217         else
 218           pam_modutil_write(fds[1], "", 1);
 219         if (towhat) {
 220           pam_modutil_write(fds[1], towhat, strlen(towhat)+1);
 221         }
 222         else
 223           pam_modutil_write(fds[1], "", 1);
 224
 225         close(fds[0]);       /* close here to avoid possible SIGPIPE above */
 226         close(fds[1]);
 227         rc=waitpid(child, &retval, 0);  /* wait for helper to complete */
 228         if (rc<0) {
 229           pam_syslog(pamh, LOG_ERR, "unix_update waitpid failed: %m");
 230           retval = PAM_AUTH_ERR;
 231         } else {
 232           retval = WEXITSTATUS(retval);
 233         }
 234     } else {
 235         D(("fork failed"));
 236         close(fds[0]);
 237         close(fds[1]);
 238         retval = PAM_AUTH_ERR;
 239     }
 240
 241     if (off(UNIX_NOREAP, ctrl)) {
 242         sigaction(SIGCHLD, &oldsa, NULL);   /* restore old signal handler */
 243     }
 244
 245     return retval;
 246 }
 247 #endif
 248
 249 static int check_old_password(const char *forwho, const char *newpass)
 250 {
 251         static char buf[16384];
 252         char *s_luser, *s_uid, *s_npas, *s_pas;
 253         int retval = PAM_SUCCESS;
 254         FILE *opwfile;
 255
 256         opwfile = fopen(OLD_PASSWORDS_FILE, "r");
 257         if (opwfile == NULL)
 258                 return PAM_ABORT;
 259
 260         while (fgets(buf, 16380, opwfile)) {
 261                 if (!strncmp(buf, forwho, strlen(forwho))) {
 262                         char *sptr;
 263                         buf[strlen(buf) - 1] = '\0';
 264                         s_luser = strtok_r(buf, ":,", &sptr);
 265                         s_uid = strtok_r(NULL, ":,", &sptr);
 266                         s_npas = strtok_r(NULL, ":,", &sptr);
 267                         s_pas = strtok_r(NULL, ":,", &sptr);
 268                         while (s_pas != NULL) {
 269                                 char *md5pass = Goodcrypt_md5(newpass, s_pas);
 270                                 if (!strcmp(md5pass, s_pas)) {
 271                                         _pam_delete(md5pass);
 272                                         retval = PAM_AUTHTOK_ERR;
 273                                         break;
 274                                 }
 275                                 s_pas = strtok_r(NULL, ":,", &sptr);
 276                                 _pam_delete(md5pass);
 277                         }
 278                         break;
 279                 }
 280         }
 281         fclose(opwfile);
 282
 283         return retval;
 284 }
 285
 286 static int _do_setpass(pam_handle_t* pamh, const char *forwho,
 287                        const char *fromwhat,
 288                        char *towhat, unsigned int ctrl, int remember)
 289 {
 290         struct passwd *pwd = NULL;
 291         int retval = 0;
 292         int unlocked = 0;
 293         char *master = NULL;
 294
 295         D(("called"));
 296
 297         pwd = getpwnam(forwho);
 298
 299         if (pwd == NULL) {
 300                 retval = PAM_AUTHTOK_ERR;
 301                 goto done;
 302         }
 303
 304         if (on(UNIX_NIS, ctrl) && _unix_comesfromsource(pamh, forwho, 0, 1)) {
 305             if ((master=getNISserver(pamh)) != NULL) {
 306                 struct timeval timeout;
 307                 struct yppasswd yppwd;
 308                 CLIENT *clnt;
 309                 int status;
 310                 enum clnt_stat err;
 311
 312                 /* Unlock passwd file to avoid deadlock */
 313                 unlock_pwdf();
 314                 unlocked = 1;
 315
 316                 /* Initialize password information */
 317                 yppwd.newpw.pw_passwd = pwd->pw_passwd;
 318                 yppwd.newpw.pw_name = pwd->pw_name;
 319                 yppwd.newpw.pw_uid = pwd->pw_uid;
 320                 yppwd.newpw.pw_gid = pwd->pw_gid;
 321                 yppwd.newpw.pw_gecos = pwd->pw_gecos;
 322                 yppwd.newpw.pw_dir = pwd->pw_dir;
 323                 yppwd.newpw.pw_shell = pwd->pw_shell;
 324                 yppwd.oldpass = fromwhat ? strdup (fromwhat) : strdup ("");
 325                 yppwd.newpw.pw_passwd = towhat;
 326
 327                 D(("Set password %s for %s", yppwd.newpw.pw_passwd, forwho));
 328
 329                 /* The yppasswd.x file said `unix authentication required',
 330                  * so I added it. This is the only reason it is in here.
 331                  * My yppasswdd doesn't use it, but maybe some others out there
 332                  * do.                                        --okir
 333                  */
 334                 clnt = clnt_create(master, YPPASSWDPROG, YPPASSWDVERS, "udp");
 335                 clnt->cl_auth = authunix_create_default();
 336                 memset((char *) &status, '\0', sizeof(status));
 337                 timeout.tv_sec = 25;
 338                 timeout.tv_usec = 0;
 339                 err = clnt_call(clnt, YPPASSWDPROC_UPDATE,
 340                                 (xdrproc_t) xdr_yppasswd, (char *) &yppwd,
 341                                 (xdrproc_t) xdr_int, (char *) &status,
 342                                 timeout);
 343
 344                 free (yppwd.oldpass);
 345
 346                 if (err) {
 347                         _make_remark(pamh, ctrl, PAM_TEXT_INFO,
 348                                 clnt_sperrno(err));
 349                 } else if (status) {
 350                         D(("Error while changing NIS password.\n"));
 351                 }
 352                 D(("The password has%s been changed on %s.",
 353                    (err || status) ? " not" : "", master));
 354                 pam_syslog(pamh, LOG_NOTICE, "password%s changed for %s on %s",
 355                          (err || status) ? " not" : "", pwd->pw_name, master);
 356
 357                 auth_destroy(clnt->cl_auth);
 358                 clnt_destroy(clnt);
 359                 if (err || status) {
 360                         _make_remark(pamh, ctrl, PAM_TEXT_INFO,
 361                                 _("NIS password could not be changed."));
 362                         retval = PAM_TRY_AGAIN;
 363                 }
 364 #ifdef DEBUG
 365                 sleep(5);
 366 #endif
 367             } else {
 368                     retval = PAM_TRY_AGAIN;
 369             }
 370         }
 371
 372         if (_unix_comesfromsource(pamh, forwho, 1, 0)) {
 373                 if(unlocked) {
 374                         if (lock_pwdf() != PAM_SUCCESS) {
 375                                 return PAM_AUTHTOK_LOCK_BUSY;
 376                         }
 377                 }
 378 #ifdef WITH_SELINUX
 379                 if (unix_selinux_confined())
 380                           return _unix_run_update_binary(pamh, ctrl, forwho, fromwhat, towhat, remember);
 381 #endif
 382                 /* first, save old password */
 383                 if (save_old_password(pamh, forwho, fromwhat, remember)) {
 384                         retval = PAM_AUTHTOK_ERR;
 385                         goto done;
 386                 }
 387                 if (on(UNIX_SHADOW, ctrl) || is_pwd_shadowed(pwd)) {
 388                         retval = unix_update_shadow(pamh, forwho, towhat);
 389                         if (retval == PAM_SUCCESS)
 390                                 if (!is_pwd_shadowed(pwd))
 391                                         retval = unix_update_passwd(pamh, forwho, "x");
 392                 } else {
 393                         retval = unix_update_passwd(pamh, forwho, towhat);
 394                 }
 395         }
 396
 397
 398 done:
 399         unlock_pwdf();
 400
 401         return retval;
 402 }
 403
 404 static int _unix_verify_shadow(pam_handle_t *pamh, const char *user, unsigned int ctrl)
 405 {
 406         struct passwd *pwent = NULL;    /* Password and shadow password */
 407         struct spwd *spent = NULL;      /* file entries for the user */
 408         int daysleft;
 409         int retval;
 410
 411         retval = get_account_info(pamh, user, &pwent, &spent);
 412         if (retval == PAM_USER_UNKNOWN) {
 413                 return retval;
 414         }
 415
 416         if (retval == PAM_SUCCESS && spent == NULL)
 417                 return PAM_SUCCESS;
 418
 419         if (retval == PAM_UNIX_RUN_HELPER) {
 420                 retval = _unix_run_verify_binary(pamh, ctrl, user, &daysleft);
 421                 if (retval == PAM_AUTH_ERR || retval == PAM_USER_UNKNOWN)
 422                         return retval;
 423         }
 424         else if (retval == PAM_SUCCESS)
 425                 retval = check_shadow_expiry(pamh, spent, &daysleft);
 426
 427         if (on(UNIX__IAMROOT, ctrl) || retval == PAM_NEW_AUTHTOK_REQD)
 428                 return PAM_SUCCESS;
 429
 430         return retval;
 431 }
 432
 433 static int _pam_unix_approve_pass(pam_handle_t * pamh
 434                                   ,unsigned int ctrl
 435                                   ,const char *pass_old
 436                                   ,const char *pass_new)
 437 {
 438         const void *user;
 439         const char *remark = NULL;
 440         int retval = PAM_SUCCESS;
 441
 442         D(("&new=%p, &old=%p", pass_old, pass_new));
 443         D(("new=[%s]", pass_new));
 444         D(("old=[%s]", pass_old));
 445
 446         if (pass_new == NULL || (pass_old && !strcmp(pass_old, pass_new))) {
 447                 if (on(UNIX_DEBUG, ctrl)) {
 448                         pam_syslog(pamh, LOG_DEBUG, "bad authentication token");
 449                 }
 450                 _make_remark(pamh, ctrl, PAM_ERROR_MSG, pass_new == NULL ?
 451                         _("No password supplied") : _("Password unchanged"));
 452                 return PAM_AUTHTOK_ERR;
 453         }
 454         /*
 455          * if one wanted to hardwire authentication token strength
 456          * checking this would be the place - AGM
 457          */
 458
 459         retval = pam_get_item(pamh, PAM_USER, &user);
 460         if (retval != PAM_SUCCESS) {
 461                 if (on(UNIX_DEBUG, ctrl)) {
 462                         pam_syslog(pamh, LOG_ERR, "Can not get username");
 463                         return PAM_AUTHTOK_ERR;
 464                 }
 465         }
 466         if (off(UNIX__IAMROOT, ctrl)) {
 467                 if (strlen(pass_new) < 6)
 468                   remark = _("You must choose a longer password");
 469                 D(("length check [%s]", remark));
 470                 if (on(UNIX_REMEMBER_PASSWD, ctrl)) {
 471                         if ((retval = check_old_password(user, pass_new)) == PAM_AUTHTOK_ERR)
 472                           remark = _("Password has been already used. Choose another.");
 473                         if (retval == PAM_ABORT) {
 474                                 pam_syslog(pamh, LOG_ERR, "can't open %s file to check old passwords",
 475                                         OLD_PASSWORDS_FILE);
 476                                 return retval;
 477                         }
 478                 }
 479         }
 480         if (remark) {
 481                 _make_remark(pamh, ctrl, PAM_ERROR_MSG, remark);
 482                 retval = PAM_AUTHTOK_ERR;
 483         }
 484         return retval;
 485 }
 486
 487
 488 PAM_EXTERN int pam_sm_chauthtok(pam_handle_t * pamh, int flags,
 489                                 int argc, const char **argv)
 490 {
 491         unsigned int ctrl, lctrl;
 492         int retval;
 493         int remember = -1;
 494         int rounds = -1;
 495
 496         /* <DO NOT free() THESE> */
 497         const char *user;
 498         const void *pass_old, *pass_new;
 499         /* </DO NOT free() THESE> */
 500
 501         D(("called."));
 502
 503         ctrl = _set_ctrl(pamh, flags, &remember, &rounds, argc, argv);
 504
 505         /*
 506          * First get the name of a user
 507          */
 508         retval = pam_get_user(pamh, &user, NULL);
 509         if (retval == PAM_SUCCESS) {
 510                 /*
 511                  * Various libraries at various times have had bugs related to
 512                  * '+' or '-' as the first character of a user name. Don't
 513                  * allow them.
 514                  */
 515                 if (user == NULL || user[0] == '-' || user[0] == '+') {
 516                         pam_syslog(pamh, LOG_ERR, "bad username [%s]", user);
 517                         return PAM_USER_UNKNOWN;
 518                 }
 519                 if (retval == PAM_SUCCESS && on(UNIX_DEBUG, ctrl))
 520                         pam_syslog(pamh, LOG_DEBUG, "username [%s] obtained",
 521                                  user);
 522         } else {
 523                 if (on(UNIX_DEBUG, ctrl))
 524                         pam_syslog(pamh, LOG_DEBUG,
 525                                  "password - could not identify user");
 526                 return retval;
 527         }
 528
 529         D(("Got username of %s", user));
 530
 531         /*
 532          * Before we do anything else, check to make sure that the user's
 533          * info is in one of the databases we can modify from this module,
 534          * which currently is 'files' and 'nis'.  We have to do this because
 535          * getpwnam() doesn't tell you *where* the information it gives you
 536          * came from, nor should it.  That's our job.
 537          */
 538         if (_unix_comesfromsource(pamh, user, 1, on(UNIX_NIS, ctrl)) == 0) {
 539                 pam_syslog(pamh, LOG_DEBUG,
 540                          "user \"%s\" does not exist in /etc/passwd%s",
 541                          user, on(UNIX_NIS, ctrl) ? " or NIS" : "");
 542                 return PAM_USER_UNKNOWN;
 543         } else {
 544                 struct passwd *pwd;
 545                 _unix_getpwnam(pamh, user, 1, 1, &pwd);
 546                 if (pwd == NULL) {
 547                         pam_syslog(pamh, LOG_DEBUG,
 548                                 "user \"%s\" has corrupted passwd entry",
 549                                 user);
 550                         return PAM_USER_UNKNOWN;
 551                 }
 552         }
 553
 554         /*
 555          * This is not an AUTH module!
 556          */
 557         if (on(UNIX__NONULL, ctrl))
 558                 set(UNIX__NULLOK, ctrl);
 559
 560         if (on(UNIX__PRELIM, ctrl)) {
 561                 /*
 562                  * obtain and verify the current password (OLDAUTHTOK) for
 563                  * the user.
 564                  */
 565                 char *Announce;
 566
 567                 D(("prelim check"));
 568
 569                 if (_unix_blankpasswd(pamh, ctrl, user)) {
 570                         return PAM_SUCCESS;
 571                 } else if (off(UNIX__IAMROOT, ctrl)) {
 572                         /* instruct user what is happening */
 573                         if (asprintf(&Announce, _("Changing password for %s."),
 574                                 user) < 0) {
 575                                 pam_syslog(pamh, LOG_CRIT,
 576                                          "password - out of memory");
 577                                 return PAM_BUF_ERR;
 578                         }
 579
 580                         lctrl = ctrl;
 581                         set(UNIX__OLD_PASSWD, lctrl);
 582                         retval = _unix_read_password(pamh, lctrl
 583                                                      ,Announce
 584                                              ,_("(current) UNIX password: ")
 585                                                      ,NULL
 586                                                      ,_UNIX_OLD_AUTHTOK
 587                                              ,&pass_old);
 588                         free(Announce);
 589
 590                         if (retval != PAM_SUCCESS) {
 591                                 pam_syslog(pamh, LOG_NOTICE,
 592                                     "password - (old) token not obtained");
 593                                 return retval;
 594                         }
 595                         /* verify that this is the password for this user */
 596
 597                         retval = _unix_verify_password(pamh, user, pass_old, ctrl);
 598                 } else {
 599                         D(("process run by root so do nothing this time around"));
 600                         pass_old = NULL;
 601                         retval = PAM_SUCCESS;   /* root doesn't have too */
 602                 }
 603
 604                 if (retval != PAM_SUCCESS) {
 605                         D(("Authentication failed"));
 606                         pass_old = NULL;
 607                         return retval;
 608                 }
 609                 retval = pam_set_item(pamh, PAM_OLDAUTHTOK, (const void *) pass_old);
 610                 pass_old = NULL;
 611                 if (retval != PAM_SUCCESS) {
 612                         pam_syslog(pamh, LOG_CRIT,
 613                                  "failed to set PAM_OLDAUTHTOK");
 614                 }
 615                 retval = _unix_verify_shadow(pamh,user, ctrl);
 616                 if (retval == PAM_AUTHTOK_ERR) {
 617                         if (off(UNIX__IAMROOT, ctrl))
 618                                 _make_remark(pamh, ctrl, PAM_ERROR_MSG,
 619                                              _("You must wait longer to change your password"));
 620                         else
 621                                 retval = PAM_SUCCESS;
 622                 }
 623         } else if (on(UNIX__UPDATE, ctrl)) {
 624                 /*
 625                  * tpass is used below to store the _pam_md() return; it
 626                  * should be _pam_delete()'d.
 627                  */
 628
 629                 char *tpass = NULL;
 630                 int retry = 0;
 631
 632                 /*
 633                  * obtain the proposed password
 634                  */
 635
 636                 D(("do update"));
 637
 638                 /*
 639                  * get the old token back. NULL was ok only if root [at this
 640                  * point we assume that this has already been enforced on a
 641                  * previous call to this function].
 642                  */
 643
 644                 if (off(UNIX_NOT_SET_PASS, ctrl)) {
 645                         retval = pam_get_item(pamh, PAM_OLDAUTHTOK
 646                                               ,&pass_old);
 647                 } else {
 648                         retval = pam_get_data(pamh, _UNIX_OLD_AUTHTOK
 649                                               ,&pass_old);
 650                         if (retval == PAM_NO_MODULE_DATA) {
 651                                 retval = PAM_SUCCESS;
 652                                 pass_old = NULL;
 653                         }
 654                 }
 655                 D(("pass_old [%s]", pass_old));
 656
 657                 if (retval != PAM_SUCCESS) {
 658                         pam_syslog(pamh, LOG_NOTICE, "user not authenticated");
 659                         return retval;
 660                 }
 661
 662                 D(("get new password now"));
 663
 664                 lctrl = ctrl;
 665
 666                 if (on(UNIX_USE_AUTHTOK, lctrl)) {
 667                         set(UNIX_USE_FIRST_PASS, lctrl);
 668                 }
 669                 retry = 0;
 670                 retval = PAM_AUTHTOK_ERR;
 671                 while ((retval != PAM_SUCCESS) && (retry++ < MAX_PASSWD_TRIES)) {
 672                         /*
 673                          * use_authtok is to force the use of a previously entered
 674                          * password -- needed for pluggable password strength checking
 675                          */
 676
 677                         retval = _unix_read_password(pamh, lctrl
 678                                                      ,NULL
 679                                              ,_("Enter new UNIX password: ")
 680                                             ,_("Retype new UNIX password: ")
 681                                                      ,_UNIX_NEW_AUTHTOK
 682                                              ,&pass_new);
 683
 684                         if (retval != PAM_SUCCESS) {
 685                                 if (on(UNIX_DEBUG, ctrl)) {
 686                                         pam_syslog(pamh, LOG_ALERT,
 687                                                  "password - new password not obtained");
 688                                 }
 689                                 pass_old = NULL;        /* tidy up */
 690                                 return retval;
 691                         }
 692                         D(("returned to _unix_chauthtok"));
 693
 694                         /*
 695                          * At this point we know who the user is and what they
 696                          * propose as their new password. Verify that the new
 697                          * password is acceptable.
 698                          */
 699
 700                         if (*(const char *)pass_new == '\0') {  /* "\0" password = NULL */
 701                                 pass_new = NULL;
 702                         }
 703                         retval = _pam_unix_approve_pass(pamh, ctrl, pass_old, pass_new);
 704
 705                         if (retval != PAM_SUCCESS && off(UNIX_NOT_SET_PASS, ctrl)) {
 706                                 pam_set_item(pamh, PAM_AUTHTOK, NULL);
 707                         }
 708                 }
 709
 710                 if (retval != PAM_SUCCESS) {
 711                         pam_syslog(pamh, LOG_NOTICE,
 712                                  "new password not acceptable");
 713                         pass_new = pass_old = NULL;     /* tidy up */
 714                         return retval;
 715                 }
 716                 if (lock_pwdf() != PAM_SUCCESS) {
 717                         return PAM_AUTHTOK_LOCK_BUSY;
 718                 }
 719
 720                 if (pass_old) {
 721                         retval = _unix_verify_password(pamh, user, pass_old, ctrl);
 722                         if (retval != PAM_SUCCESS) {
 723                                 pam_syslog(pamh, LOG_NOTICE, "user password changed by another process");
 724                                 unlock_pwdf();
 725                                 return retval;
 726                         }
 727                 }
 728
 729                 retval = _unix_verify_shadow(pamh, user, ctrl);
 730                 if (retval != PAM_SUCCESS) {
 731                         pam_syslog(pamh, LOG_NOTICE, "user shadow entry expired");
 732                         unlock_pwdf();
 733                         return retval;
 734                 }
 735
 736                 retval = _pam_unix_approve_pass(pamh, ctrl, pass_old, pass_new);
 737                 if (retval != PAM_SUCCESS) {
 738                         pam_syslog(pamh, LOG_NOTICE,
 739                                  "new password not acceptable 2");
 740                         pass_new = pass_old = NULL;     /* tidy up */
 741                         unlock_pwdf();
 742                         return retval;
 743                 }
 744
 745                 /*
 746                  * By reaching here we have approved the passwords and must now
 747                  * rebuild the password database file.
 748                  */
 749
 750                 /*
 751                  * First we encrypt the new password.
 752                  */
 753
 754                 tpass = create_password_hash(pamh, pass_new, ctrl, rounds);
 755                 if (tpass == NULL) {
 756                         pam_syslog(pamh, LOG_CRIT,
 757                                 "out of memory for password");
 758                         pass_new = pass_old = NULL;     /* tidy up */
 759                         unlock_pwdf();
 760                         return PAM_BUF_ERR;
 761                 }
 762
 763                 D(("password processed"));
 764
 765                 /* update the password database(s) -- race conditions..? */
 766
 767                 retval = _do_setpass(pamh, user, pass_old, tpass, ctrl,
 768                                      remember);
 769                 /* _do_setpass has called unlock_pwdf for us */
 770
 771                 _pam_delete(tpass);
 772                 pass_old = pass_new = NULL;
 773         } else {                /* something has broken with the module */
 774                 pam_syslog(pamh, LOG_ALERT,
 775                          "password received unknown request");
 776                 retval = PAM_ABORT;
 777         }
 778
 779         D(("retval was %d", retval));
 780
 781         return retval;
 782 }
 783
 784
 785 /* static module data */
 786 #ifdef PAM_STATIC
 787 struct pam_module _pam_unix_passwd_modstruct = {
 788     "pam_unix_passwd",
 789     NULL,
 790     NULL,
 791     NULL,
 792     NULL,
 793     NULL,
 794     pam_sm_chauthtok,
 795 };
 796 #endif