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