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

   1 /*
   2  * $Id$
   3  *
   4  * Copyright information at end of file.
   5  */
   6
   7 #define _BSD_SOURCE
   8
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <stdarg.h>
  12 #include <string.h>
  13 #include <malloc.h>
  14 #include <pwd.h>
  15 #include <shadow.h>
  16 #include <limits.h>
  17 #include <utmp.h>
  18
  19 #include <security/_pam_macros.h>
  20 #include <security/pam_modules.h>
  21
  22 #include "md5.h"
  23 #include "support.h"
  24
  25 extern char *crypt(const char *key, const char *salt);
  26 extern char *bigcrypt(const char *key, const char *salt);
  27
  28 /* syslogging function for errors and other information */
  29
  30 void _log_err(int err, pam_handle_t *pamh, const char *format,...)
  31 {
  32         char *service = NULL;
  33         char logname[256];
  34         va_list args;
  35
  36         pam_get_item(pamh, PAM_SERVICE, (const void **) &service);
  37         if (service) {
  38                 strncpy(logname, service, sizeof(logname));
  39                 logname[sizeof(logname) - 1 - strlen("(pam_unix)")] = '\0';
  40                 strncat(logname, "(pam_unix)", strlen("(pam_unix)"));
  41         } else {
  42                 strncpy(logname, "pam_unix", sizeof(logname) - 1);
  43         }
  44
  45         va_start(args, format);
  46         openlog(logname, LOG_CONS | LOG_PID, LOG_AUTH);
  47         vsyslog(err, format, args);
  48         va_end(args);
  49         closelog();
  50 }
  51
  52 /* this is a front-end for module-application conversations */
  53
  54 static int converse(pam_handle_t * pamh, int ctrl, int nargs
  55                     ,struct pam_message **message
  56                     ,struct pam_response **response)
  57 {
  58         int retval;
  59         struct pam_conv *conv;
  60
  61         D(("begin to converse"));
  62
  63         retval = pam_get_item(pamh, PAM_CONV, (const void **) &conv);
  64         if (retval == PAM_SUCCESS) {
  65
  66                 retval = conv->conv(nargs, (const struct pam_message **) message
  67                                     ,response, conv->appdata_ptr);
  68
  69                 D(("returned from application's conversation function"));
  70
  71                 if (retval != PAM_SUCCESS && on(UNIX_DEBUG, ctrl)) {
  72                         _log_err(LOG_DEBUG, pamh, "conversation failure [%s]"
  73                                  ,pam_strerror(pamh, retval));
  74                 }
  75         } else if (retval != PAM_CONV_AGAIN) {
  76                 _log_err(LOG_ERR, pamh
  77                          ,"couldn't obtain coversation function [%s]"
  78                          ,pam_strerror(pamh, retval));
  79         }
  80         D(("ready to return from module conversation"));
  81
  82         return retval;          /* propagate error status */
  83 }
  84
  85 int _make_remark(pam_handle_t * pamh, unsigned int ctrl
  86                        ,int type, const char *text)
  87 {
  88         int retval = PAM_SUCCESS;
  89
  90         if (off(UNIX__QUIET, ctrl)) {
  91                 struct pam_message *pmsg[1], msg[1];
  92                 struct pam_response *resp;
  93
  94                 pmsg[0] = &msg[0];
  95                 msg[0].msg = text;
  96                 msg[0].msg_style = type;
  97
  98                 resp = NULL;
  99                 retval = converse(pamh, ctrl, 1, pmsg, &resp);
 100
 101                 if (resp) {
 102                         _pam_drop_reply(resp, 1);
 103                 }
 104         }
 105         return retval;
 106 }
 107
 108   /*
 109    * Beacause getlogin() is braindead and sometimes it just
 110    * doesn't work, we reimplement it here.
 111    */
 112 char *PAM_getlogin(void)
 113 {
 114         struct utmp *ut, line;
 115         char *curr_tty, *retval;
 116         static char curr_user[sizeof(ut->ut_user) + 4];
 117
 118         retval = NULL;
 119
 120         curr_tty = ttyname(0);
 121         if (curr_tty != NULL) {
 122                 D(("PAM_getlogin ttyname: %s", curr_tty));
 123                 curr_tty += 5;
 124                 setutent();
 125                 strncpy(line.ut_line, curr_tty, sizeof line.ut_line);
 126                 if ((ut = getutline(&line)) != NULL) {
 127                         strncpy(curr_user, ut->ut_user, sizeof(ut->ut_user));
 128                         retval = curr_user;
 129                 }
 130                 endutent();
 131         }
 132         D(("PAM_getlogin retval: %s", retval));
 133
 134         return retval;
 135 }
 136
 137 /*
 138  * set the control flags for the UNIX module.
 139  */
 140
 141 int _set_ctrl(pam_handle_t *pamh, int flags, int *remember, int argc,
 142               const char **argv)
 143 {
 144         unsigned int ctrl;
 145
 146         D(("called."));
 147
 148         ctrl = UNIX_DEFAULTS;   /* the default selection of options */
 149
 150         /* set some flags manually */
 151
 152         if (getuid() == 0 && !(flags & PAM_CHANGE_EXPIRED_AUTHTOK)) {
 153                 D(("IAMROOT"));
 154                 set(UNIX__IAMROOT, ctrl);
 155         }
 156         if (flags & PAM_UPDATE_AUTHTOK) {
 157                 D(("UPDATE_AUTHTOK"));
 158                 set(UNIX__UPDATE, ctrl);
 159         }
 160         if (flags & PAM_PRELIM_CHECK) {
 161                 D(("PRELIM_CHECK"));
 162                 set(UNIX__PRELIM, ctrl);
 163         }
 164         if (flags & PAM_DISALLOW_NULL_AUTHTOK) {
 165                 D(("DISALLOW_NULL_AUTHTOK"));
 166                 set(UNIX__NONULL, ctrl);
 167         }
 168         if (flags & PAM_SILENT) {
 169                 D(("SILENT"));
 170                 set(UNIX__QUIET, ctrl);
 171         }
 172         /* now parse the arguments to this module */
 173
 174         while (argc-- > 0) {
 175                 int j;
 176
 177                 D(("pam_unix arg: %s", *argv));
 178
 179                 for (j = 0; j < UNIX_CTRLS_; ++j) {
 180                         if (unix_args[j].token
 181                             && !strncmp(*argv, unix_args[j].token, strlen(unix_args[j].token))) {
 182                                 break;
 183                         }
 184                 }
 185
 186                 if (j >= UNIX_CTRLS_) {
 187                         _log_err(LOG_ERR, pamh,
 188                                  "unrecognized option [%s]", *argv);
 189                 } else {
 190                         ctrl &= unix_args[j].mask;      /* for turning things off */
 191                         ctrl |= unix_args[j].flag;      /* for turning things on  */
 192
 193                         if (remember != NULL) {
 194                                 if (j == UNIX_REMEMBER_PASSWD) {
 195                                         *remember = strtol(*argv + 9, NULL, 10);
 196                                         if ((*remember == LONG_MIN) || (*remember == LONG_MAX))
 197                                                 *remember = -1;
 198                                         if (*remember > 400)
 199                                                 *remember = 400;
 200                                 }
 201                         }
 202                 }
 203
 204                 ++argv;         /* step to next argument */
 205         }
 206
 207         /* auditing is a more sensitive version of debug */
 208
 209         if (on(UNIX_AUDIT, ctrl)) {
 210                 set(UNIX_DEBUG, ctrl);
 211         }
 212         /* return the set of flags */
 213
 214         D(("done."));
 215         return ctrl;
 216 }
 217
 218 static void _cleanup(pam_handle_t * pamh, void *x, int error_status)
 219 {
 220         _pam_delete(x);
 221 }
 222
 223 /* ************************************************************** *
 224  * Useful non-trivial functions                                   *
 225  * ************************************************************** */
 226
 227   /*
 228    * the following is used to keep track of the number of times a user fails
 229    * to authenticate themself.
 230    */
 231
 232 #define FAIL_PREFIX                   "-UN*X-FAIL-"
 233 #define UNIX_MAX_RETRIES              3
 234
 235 struct _pam_failed_auth {
 236         char *user;             /* user that's failed to be authenticated */
 237         char *name;             /* attempt from user with name */
 238         int uid;                /* uid of calling user */
 239         int euid;               /* euid of calling process */
 240         int count;              /* number of failures so far */
 241 };
 242
 243 #ifndef PAM_DATA_REPLACE
 244 #error "Need to get an updated libpam 0.52 or better"
 245 #endif
 246
 247 static void _cleanup_failures(pam_handle_t * pamh, void *fl, int err)
 248 {
 249         int quiet;
 250         const char *service = NULL;
 251         const char *ruser = NULL;
 252         const char *rhost = NULL;
 253         const char *tty = NULL;
 254         struct _pam_failed_auth *failure;
 255
 256         D(("called"));
 257
 258         quiet = err & PAM_DATA_SILENT;  /* should we log something? */
 259         err &= PAM_DATA_REPLACE;        /* are we just replacing data? */
 260         failure = (struct _pam_failed_auth *) fl;
 261
 262         if (failure != NULL) {
 263
 264                 if (!quiet && !err) {   /* under advisement from Sun,may go away */
 265
 266                         /* log the number of authentication failures */
 267                         if (failure->count > 1) {
 268                                 (void) pam_get_item(pamh, PAM_SERVICE,
 269                                                     (const void **)&service);
 270                                 (void) pam_get_item(pamh, PAM_RUSER,
 271                                                     (const void **)&ruser);
 272                                 (void) pam_get_item(pamh, PAM_RHOST,
 273                                                     (const void **)&rhost);
 274                                 (void) pam_get_item(pamh, PAM_TTY,
 275                                                     (const void **)&tty);
 276                                 _log_err(LOG_NOTICE, pamh,
 277                                          "%d more authentication failure%s; "
 278                                          "logname=%s uid=%d euid=%d "
 279                                          "tty=%s ruser=%s rhost=%s "
 280                                          "%s%s",
 281                                          failure->count - 1, failure->count == 2 ? "" : "s",
 282                                          failure->name, failure->uid, failure->euid,
 283                                          tty ? tty : "", ruser ? ruser : "",
 284                                          rhost ? rhost : "",
 285                                          (failure->user && failure->user[0] != '\0')
 286                                           ? " user=" : "", failure->user
 287                                 );
 288
 289                                 if (failure->count > UNIX_MAX_RETRIES) {
 290                                         _log_err(LOG_ALERT, pamh
 291                                                  ,"service(%s) ignoring max retries; %d > %d"
 292                                                  ,service == NULL ? "**unknown**" : service
 293                                                  ,failure->count
 294                                                  ,UNIX_MAX_RETRIES);
 295                                 }
 296                         }
 297                 }
 298                 _pam_delete(failure->user);     /* tidy up */
 299                 _pam_delete(failure->name);     /* tidy up */
 300                 free(failure);
 301         }
 302 }
 303
 304 /*
 305  * _unix_blankpasswd() is a quick check for a blank password
 306  *
 307  * returns TRUE if user does not have a password
 308  * - to avoid prompting for one in such cases (CG)
 309  */
 310
 311 int _unix_blankpasswd(unsigned int ctrl, const char *name)
 312 {
 313         struct passwd *pwd = NULL;
 314         struct spwd *spwdent = NULL;
 315         char *salt = NULL;
 316         int retval;
 317
 318         D(("called"));
 319
 320         /*
 321          * This function does not have to be too smart if something goes
 322          * wrong, return FALSE and let this case to be treated somewhere
 323          * else (CG)
 324          */
 325
 326         if (on(UNIX__NONULL, ctrl))
 327                 return 0;       /* will fail but don't let on yet */
 328
 329         /* UNIX passwords area */
 330         pwd = getpwnam(name);   /* Get password file entry... */
 331
 332         if (pwd != NULL) {
 333                 if (strcmp( pwd->pw_passwd, "*NP*" ) == 0)
 334                 { /* NIS+ */
 335                         uid_t save_euid, save_uid;
 336
 337                         save_euid = geteuid();
 338                         save_uid = getuid();
 339                         if (save_uid == pwd->pw_uid)
 340                                 setreuid( save_euid, save_uid );
 341                         else  {
 342                                 setreuid( 0, -1 );
 343                                 if (setreuid( -1, pwd->pw_uid ) == -1) {
 344                                         setreuid( -1, 0 );
 345                                         setreuid( 0, -1 );
 346                                         if(setreuid( -1, pwd->pw_uid ) == -1)
 347                                                 /* Will fail elsewhere. */
 348                                                 return 0;
 349                                 }
 350                         }
 351
 352                         spwdent = getspnam( name );
 353                         if (save_uid == pwd->pw_uid)
 354                                 setreuid( save_uid, save_euid );
 355                         else {
 356                                 if (setreuid( -1, 0 ) == -1)
 357                                 setreuid( save_uid, -1 );
 358                                 setreuid( -1, save_euid );
 359                         }
 360                 } else if (strcmp(pwd->pw_passwd, "x") == 0) {
 361                         /*
 362                          * ...and shadow password file entry for this user,
 363                          * if shadowing is enabled
 364                          */
 365                         spwdent = getspnam(name);
 366                 }
 367                 if (spwdent)
 368                         salt = x_strdup(spwdent->sp_pwdp);
 369                 else
 370                         salt = x_strdup(pwd->pw_passwd);
 371         }
 372         /* Does this user have a password? */
 373         if (salt == NULL) {
 374                 retval = 0;
 375         } else {
 376                 if (strlen(salt) == 0)
 377                         retval = 1;
 378                 else
 379                         retval = 0;
 380         }
 381
 382         /* tidy up */
 383
 384         if (salt)
 385                 _pam_delete(salt);
 386
 387         return retval;
 388 }
 389
 390 /*
 391  * verify the password of a user
 392  */
 393
 394 #include <sys/types.h>
 395 #include <sys/wait.h>
 396
 397 static int _unix_run_helper_binary(pam_handle_t *pamh, const char *passwd, unsigned int ctrl)
 398 {
 399     int retval, child, fds[2];
 400
 401     D(("called."));
 402     /* create a pipe for the password */
 403     if (pipe(fds) != 0) {
 404         D(("could not make pipe"));
 405         return PAM_AUTH_ERR;
 406     }
 407
 408     /* fork */
 409     child = fork();
 410     if (child == 0) {
 411         static char *args[] = { NULL, NULL };
 412         static char *envp[] = { NULL };
 413
 414         /* XXX - should really tidy up PAM here too */
 415
 416         /* reopen stdin as pipe */
 417         close(fds[1]);
 418         dup2(fds[0], STDIN_FILENO);
 419
 420         /* exec binary helper */
 421         args[0] = x_strdup(CHKPWD_HELPER);
 422         execve(CHKPWD_HELPER, args, envp);
 423
 424         /* should not get here: exit with error */
 425         D(("helper binary is not available"));
 426         exit(PAM_AUTHINFO_UNAVAIL);
 427     } else if (child > 0) {
 428         /* wait for child */
 429         /* if the stored password is NULL */
 430         if (off(UNIX__NONULL, ctrl)) {  /* this means we've succeeded */
 431             write(fds[1], "nullok\0\0", 8);
 432         } else {
 433             write(fds[1], "nonull\0\0", 8);
 434         }
 435         if (passwd != NULL) {            /* send the password to the child */
 436             write(fds[1], passwd, strlen(passwd)+1);
 437             passwd = NULL;
 438         } else {
 439             write(fds[1], "", 1);                        /* blank password */
 440         }
 441         close(fds[0]);       /* close here to avoid possible SIGPIPE above */
 442         close(fds[1]);
 443         (void) waitpid(child, &retval, 0);  /* wait for helper to complete */
 444         retval = (retval == 0) ? PAM_SUCCESS:PAM_AUTH_ERR;
 445     } else {
 446         D(("fork failed"));
 447         retval = PAM_AUTH_ERR;
 448     }
 449
 450     D(("returning %d", retval));
 451     return retval;
 452 }
 453
 454 int _unix_verify_password(pam_handle_t * pamh, const char *name
 455                           ,const char *p, unsigned int ctrl)
 456 {
 457         struct passwd *pwd = NULL;
 458         struct spwd *spwdent = NULL;
 459         char *salt = NULL;
 460         char *pp = NULL;
 461         char *data_name;
 462         int retval;
 463
 464         D(("called"));
 465
 466 #ifdef HAVE_PAM_FAIL_DELAY
 467         if (off(UNIX_NODELAY, ctrl)) {
 468                 D(("setting delay"));
 469                 (void) pam_fail_delay(pamh, 2000000);   /* 2 sec delay for on failure */
 470         }
 471 #endif
 472
 473         /* locate the entry for this user */
 474
 475         D(("locating user's record"));
 476
 477         /* UNIX passwords area */
 478         pwd = getpwnam(name);   /* Get password file entry... */
 479
 480         if (pwd != NULL) {
 481                 if (strcmp( pwd->pw_passwd, "*NP*" ) == 0)
 482                 { /* NIS+ */
 483                         uid_t save_euid, save_uid;
 484
 485                         save_euid = geteuid();
 486                         save_uid = getuid();
 487                         if (save_uid == pwd->pw_uid)
 488                                 setreuid( save_euid, save_uid );
 489                         else  {
 490                                 setreuid( 0, -1 );
 491                                 if (setreuid( -1, pwd->pw_uid ) == -1) {
 492                                         setreuid( -1, 0 );
 493                                         setreuid( 0, -1 );
 494                                         if(setreuid( -1, pwd->pw_uid ) == -1)
 495                                                 return PAM_CRED_INSUFFICIENT;
 496                                 }
 497                         }
 498
 499                         spwdent = getspnam( name );
 500                         if (save_uid == pwd->pw_uid)
 501                                 setreuid( save_uid, save_euid );
 502                         else {
 503                                 if (setreuid( -1, 0 ) == -1)
 504                                 setreuid( save_uid, -1 );
 505                                 setreuid( -1, save_euid );
 506                         }
 507                 } else if (strcmp(pwd->pw_passwd, "x") == 0) {
 508                         /*
 509                          * ...and shadow password file entry for this user,
 510                          * if shadowing is enabled
 511                          */
 512                         spwdent = getspnam(name);
 513                 }
 514                 if (spwdent)
 515                         salt = x_strdup(spwdent->sp_pwdp);
 516                 else
 517                         salt = x_strdup(pwd->pw_passwd);
 518         }
 519
 520         data_name = (char *) malloc(sizeof(FAIL_PREFIX) + strlen(name));
 521         if (data_name == NULL) {
 522                 _log_err(LOG_CRIT, pamh, "no memory for data-name");
 523         } else {
 524                 strcpy(data_name, FAIL_PREFIX);
 525                 strcpy(data_name + sizeof(FAIL_PREFIX) - 1, name);
 526         }
 527
 528         retval = PAM_SUCCESS;
 529         if (pwd == NULL || salt == NULL || !strcmp(salt, "x")) {
 530                 if (geteuid()) {
 531                         /* we are not root perhaps this is the reason? Run helper */
 532                         D(("running helper binary"));
 533                         retval = _unix_run_helper_binary(pamh, p, ctrl);
 534                         if (pwd == NULL && !on(UNIX_AUDIT,ctrl)
 535                             && retval != PAM_SUCCESS)
 536                         {
 537                                 name = NULL;
 538                         }
 539                 } else {
 540                         D(("user's record unavailable"));
 541                         if (on(UNIX_AUDIT, ctrl)) {
 542                                 /* this might be a typo and the user has given a password
 543                                    instead of a username. Careful with this. */
 544                                 _log_err(LOG_ALERT, pamh,
 545                                          "check pass; user (%s) unknown", name);
 546                         } else {
 547                                 name = NULL;
 548                                 _log_err(LOG_ALERT, pamh,
 549                                          "check pass; user unknown");
 550                         }
 551                         p = NULL;
 552                         retval = PAM_AUTHINFO_UNAVAIL;
 553                 }
 554         } else {
 555                 if (!strlen(salt)) {
 556                         /* the stored password is NULL */
 557                         if (off(UNIX__NONULL, ctrl)) {  /* this means we've succeeded */
 558                                 D(("user has empty password - access granted"));
 559                                 retval = PAM_SUCCESS;
 560                         } else {
 561                                 D(("user has empty password - access denied"));
 562                                 retval = PAM_AUTH_ERR;
 563                         }
 564                 } else if (!p) {
 565                                 retval = PAM_AUTH_ERR;
 566                 } else {
 567                         if (!strncmp(salt, "$1$", 3)) {
 568                                 pp = Goodcrypt_md5(p, salt);
 569                                 if (strcmp(pp, salt) != 0) {
 570                                         pp = Brokencrypt_md5(p, salt);
 571                                 }
 572                         } else {
 573                                 pp = bigcrypt(p, salt);
 574                         }
 575                         p = NULL;               /* no longer needed here */
 576
 577                         /* the moment of truth -- do we agree with the password? */
 578                         D(("comparing state of pp[%s] and salt[%s]", pp, salt));
 579
 580                         if (strcmp(pp, salt) == 0) {
 581                                 retval = PAM_SUCCESS;
 582                         } else {
 583                                 retval = PAM_AUTH_ERR;
 584                         }
 585                 }
 586         }
 587
 588         if (retval == PAM_SUCCESS) {
 589                 if (data_name)  /* reset failures */
 590                         pam_set_data(pamh, data_name, NULL, _cleanup_failures);
 591         } else {
 592                 if (data_name != NULL) {
 593                         struct _pam_failed_auth *new = NULL;
 594                         const struct _pam_failed_auth *old = NULL;
 595
 596                         /* get a failure recorder */
 597
 598                         new = (struct _pam_failed_auth *)
 599                             malloc(sizeof(struct _pam_failed_auth));
 600
 601                         if (new != NULL) {
 602
 603                                 new->user = x_strdup(name ? name : "");
 604                                 new->uid = getuid();
 605                                 new->euid = geteuid();
 606                                 new->name = x_strdup(PAM_getlogin()? PAM_getlogin() : "");
 607
 608                                 /* any previous failures for this user ? */
 609                                 pam_get_data(pamh, data_name, (const void **) &old);
 610
 611                                 if (old != NULL) {
 612                                         new->count = old->count + 1;
 613                                         if (new->count >= UNIX_MAX_RETRIES) {
 614                                                 retval = PAM_MAXTRIES;
 615                                         }
 616                                 } else {
 617                                         const char *service=NULL;
 618                                         const char *ruser=NULL;
 619                                         const char *rhost=NULL;
 620                                         const char *tty=NULL;
 621
 622                                         (void) pam_get_item(pamh, PAM_SERVICE,
 623                                                             (const void **)&service);
 624                                         (void) pam_get_item(pamh, PAM_RUSER,
 625                                                             (const void **)&ruser);
 626                                         (void) pam_get_item(pamh, PAM_RHOST,
 627                                                             (const void **)&rhost);
 628                                         (void) pam_get_item(pamh, PAM_TTY,
 629                                                             (const void **)&tty);
 630
 631                                         _log_err(LOG_NOTICE, pamh,
 632                                                  "authentication failure; "
 633                                                  "logname=%s uid=%d euid=%d "
 634                                                  "tty=%s ruser=%s rhost=%s "
 635                                                  "%s%s",
 636                                                  new->name, new->uid, new->euid,
 637                                                  tty ? tty : "",
 638                                                  ruser ? ruser : "",
 639                                                  rhost ? rhost : "",
 640                                                  (new->user && new->user[0] != '\0')
 641                                                   ? " user=" : "",
 642                                                  new->user
 643                                         );
 644                                         new->count = 1;
 645                                 }
 646
 647                                 pam_set_data(pamh, data_name, new, _cleanup_failures);
 648
 649                         } else {
 650                                 _log_err(LOG_CRIT, pamh,
 651                                          "no memory for failure recorder");
 652                         }
 653                 }
 654         }
 655
 656         if (data_name)
 657                 _pam_delete(data_name);
 658         if (salt)
 659                 _pam_delete(salt);
 660         if (pp)
 661                 _pam_overwrite(pp);
 662
 663         D(("done [%d].", retval));
 664
 665         return retval;
 666 }
 667
 668 /*
 669  * obtain a password from the user
 670  */
 671
 672 int _unix_read_password(pam_handle_t * pamh
 673                         ,unsigned int ctrl
 674                         ,const char *comment
 675                         ,const char *prompt1
 676                         ,const char *prompt2
 677                         ,const char *data_name
 678                         ,const char **pass)
 679 {
 680         int authtok_flag;
 681         int retval;
 682         const char *item;
 683         char *token;
 684
 685         D(("called"));
 686
 687         /*
 688          * make sure nothing inappropriate gets returned
 689          */
 690
 691         *pass = token = NULL;
 692
 693         /*
 694          * which authentication token are we getting?
 695          */
 696
 697         authtok_flag = on(UNIX__OLD_PASSWD, ctrl) ? PAM_OLDAUTHTOK : PAM_AUTHTOK;
 698
 699         /*
 700          * should we obtain the password from a PAM item ?
 701          */
 702
 703         if (on(UNIX_TRY_FIRST_PASS, ctrl) || on(UNIX_USE_FIRST_PASS, ctrl)) {
 704                 retval = pam_get_item(pamh, authtok_flag, (const void **) &item);
 705                 if (retval != PAM_SUCCESS) {
 706                         /* very strange. */
 707                         _log_err(LOG_ALERT, pamh
 708                                  ,"pam_get_item returned error to unix-read-password"
 709                             );
 710                         return retval;
 711                 } else if (item != NULL) {      /* we have a password! */
 712                         *pass = item;
 713                         item = NULL;
 714                         return PAM_SUCCESS;
 715                 } else if (on(UNIX_USE_FIRST_PASS, ctrl)) {
 716                         return PAM_AUTHTOK_RECOVER_ERR;         /* didn't work */
 717                 } else if (on(UNIX_USE_AUTHTOK, ctrl)
 718                            && off(UNIX__OLD_PASSWD, ctrl)) {
 719                         return PAM_AUTHTOK_RECOVER_ERR;
 720                 }
 721         }
 722         /*
 723          * getting here implies we will have to get the password from the
 724          * user directly.
 725          */
 726
 727         {
 728                 struct pam_message msg[3], *pmsg[3];
 729                 struct pam_response *resp;
 730                 int i, replies;
 731
 732                 /* prepare to converse */
 733
 734                 if (comment != NULL && off(UNIX__QUIET, ctrl)) {
 735                         pmsg[0] = &msg[0];
 736                         msg[0].msg_style = PAM_TEXT_INFO;
 737                         msg[0].msg = comment;
 738                         i = 1;
 739                 } else {
 740                         i = 0;
 741                 }
 742
 743                 pmsg[i] = &msg[i];
 744                 msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
 745                 msg[i++].msg = prompt1;
 746                 replies = 1;
 747
 748                 if (prompt2 != NULL) {
 749                         pmsg[i] = &msg[i];
 750                         msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
 751                         msg[i++].msg = prompt2;
 752                         ++replies;
 753                 }
 754                 /* so call the conversation expecting i responses */
 755                 resp = NULL;
 756                 retval = converse(pamh, ctrl, i, pmsg, &resp);
 757
 758                 if (resp != NULL) {
 759
 760                         /* interpret the response */
 761
 762                         if (retval == PAM_SUCCESS) {    /* a good conversation */
 763
 764                                 token = x_strdup(resp[i - replies].resp);
 765                                 if (token != NULL) {
 766                                         if (replies == 2) {
 767
 768                                                 /* verify that password entered correctly */
 769                                                 if (!resp[i - 1].resp
 770                                                     || strcmp(token, resp[i - 1].resp)) {
 771                                                         _pam_delete(token);     /* mistyped */
 772                                                         retval = PAM_AUTHTOK_RECOVER_ERR;
 773                                                         _make_remark(pamh, ctrl
 774                                                                     ,PAM_ERROR_MSG, MISTYPED_PASS);
 775                                                 }
 776                                         }
 777                                 } else {
 778                                         _log_err(LOG_NOTICE, pamh
 779                                                  ,"could not recover authentication token");
 780                                 }
 781
 782                         }
 783                         /*
 784                          * tidy up the conversation (resp_retcode) is ignored
 785                          * -- what is it for anyway? AGM
 786                          */
 787
 788                         _pam_drop_reply(resp, i);
 789
 790                 } else {
 791                         retval = (retval == PAM_SUCCESS)
 792                             ? PAM_AUTHTOK_RECOVER_ERR : retval;
 793                 }
 794         }
 795
 796         if (retval != PAM_SUCCESS) {
 797                 if (on(UNIX_DEBUG, ctrl))
 798                         _log_err(LOG_DEBUG, pamh,
 799                                  "unable to obtain a password");
 800                 return retval;
 801         }
 802         /* 'token' is the entered password */
 803
 804         if (off(UNIX_NOT_SET_PASS, ctrl)) {
 805
 806                 /* we store this password as an item */
 807
 808                 retval = pam_set_item(pamh, authtok_flag, token);
 809                 _pam_delete(token);     /* clean it up */
 810                 if (retval != PAM_SUCCESS
 811                     || (retval = pam_get_item(pamh, authtok_flag
 812                                               ,(const void **) &item))
 813                     != PAM_SUCCESS) {
 814
 815                         _log_err(LOG_CRIT, pamh, "error manipulating password");
 816                         return retval;
 817
 818                 }
 819         } else {
 820                 /*
 821                  * then store it as data specific to this module. pam_end()
 822                  * will arrange to clean it up.
 823                  */
 824
 825                 retval = pam_set_data(pamh, data_name, (void *) token, _cleanup);
 826                 if (retval != PAM_SUCCESS) {
 827                         _log_err(LOG_CRIT, pamh
 828                                  ,"error manipulating password data [%s]"
 829                                  ,pam_strerror(pamh, retval));
 830                         _pam_delete(token);
 831                         return retval;
 832                 }
 833                 item = token;
 834                 token = NULL;   /* break link to password */
 835         }
 836
 837         *pass = item;
 838         item = NULL;            /* break link to password */
 839
 840         return PAM_SUCCESS;
 841 }
 842
 843 /* ****************************************************************** *
 844  * Copyright (c) Jan Rêkorajski 1999.
 845  * Copyright (c) Andrew G. Morgan 1996-8.
 846  * Copyright (c) Alex O. Yuriev, 1996.
 847  * Copyright (c) Cristian Gafton 1996.
 848  *
 849  * Redistribution and use in source and binary forms, with or without
 850  * modification, are permitted provided that the following conditions
 851  * are met:
 852  * 1. Redistributions of source code must retain the above copyright
 853  *    notice, and the entire permission notice in its entirety,
 854  *    including the disclaimer of warranties.
 855  * 2. Redistributions in binary form must reproduce the above copyright
 856  *    notice, this list of conditions and the following disclaimer in the
 857  *    documentation and/or other materials provided with the distribution.
 858  * 3. The name of the author may not be used to endorse or promote
 859  *    products derived from this software without specific prior
 860  *    written permission.
 861  *
 862  * ALTERNATIVELY, this product may be distributed under the terms of
 863  * the GNU Public License, in which case the provisions of the GPL are
 864  * required INSTEAD OF the above restrictions.  (This clause is
 865  * necessary due to a potential bad interaction between the GPL and
 866  * the restrictions contained in a BSD-style copyright.)
 867  *
 868  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 869  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 870  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 871  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 872  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 873  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 874  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 875  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 876  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 877  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 878  * OF THE POSSIBILITY OF SUCH DAMAGE.
 879  */