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,
 398                                    unsigned int ctrl, const char *user)
 399 {
 400     int retval, child, fds[2];
 401
 402     D(("called."));
 403     /* create a pipe for the password */
 404     if (pipe(fds) != 0) {
 405         D(("could not make pipe"));
 406         return PAM_AUTH_ERR;
 407     }
 408
 409     /* fork */
 410     child = fork();
 411     if (child == 0) {
 412         static char *envp[] = { NULL };
 413         char *args[] = { NULL, NULL, NULL };
 414
 415         /* XXX - should really tidy up PAM here too */
 416
 417         /* reopen stdin as pipe */
 418         close(fds[1]);
 419         dup2(fds[0], STDIN_FILENO);
 420
 421         /* exec binary helper */
 422         args[0] = x_strdup(CHKPWD_HELPER);
 423         args[1] = x_strdup(user);
 424
 425         execve(CHKPWD_HELPER, args, envp);
 426
 427         /* should not get here: exit with error */
 428         D(("helper binary is not available"));
 429         exit(PAM_AUTHINFO_UNAVAIL);
 430     } else if (child > 0) {
 431         /* wait for child */
 432         /* if the stored password is NULL */
 433         if (off(UNIX__NONULL, ctrl)) {  /* this means we've succeeded */
 434             write(fds[1], "nullok\0\0", 8);
 435         } else {
 436             write(fds[1], "nonull\0\0", 8);
 437         }
 438         if (passwd != NULL) {            /* send the password to the child */
 439             write(fds[1], passwd, strlen(passwd)+1);
 440             passwd = NULL;
 441         } else {
 442             write(fds[1], "", 1);                        /* blank password */
 443         }
 444         close(fds[0]);       /* close here to avoid possible SIGPIPE above */
 445         close(fds[1]);
 446         (void) waitpid(child, &retval, 0);  /* wait for helper to complete */
 447         retval = (retval == 0) ? PAM_SUCCESS:PAM_AUTH_ERR;
 448     } else {
 449         D(("fork failed"));
 450         retval = PAM_AUTH_ERR;
 451     }
 452
 453     D(("returning %d", retval));
 454     return retval;
 455 }
 456
 457 int _unix_verify_password(pam_handle_t * pamh, const char *name
 458                           ,const char *p, unsigned int ctrl)
 459 {
 460         struct passwd *pwd = NULL;
 461         struct spwd *spwdent = NULL;
 462         char *salt = NULL;
 463         char *pp = NULL;
 464         char *data_name;
 465         int retval;
 466
 467         D(("called"));
 468
 469 #ifdef HAVE_PAM_FAIL_DELAY
 470         if (off(UNIX_NODELAY, ctrl)) {
 471                 D(("setting delay"));
 472                 (void) pam_fail_delay(pamh, 2000000);   /* 2 sec delay for on failure */
 473         }
 474 #endif
 475
 476         /* locate the entry for this user */
 477
 478         D(("locating user's record"));
 479
 480         /* UNIX passwords area */
 481         pwd = getpwnam(name);   /* Get password file entry... */
 482
 483         if (pwd != NULL) {
 484                 if (strcmp( pwd->pw_passwd, "*NP*" ) == 0)
 485                 { /* NIS+ */
 486                         uid_t save_euid, save_uid;
 487
 488                         save_euid = geteuid();
 489                         save_uid = getuid();
 490                         if (save_uid == pwd->pw_uid)
 491                                 setreuid( save_euid, save_uid );
 492                         else  {
 493                                 setreuid( 0, -1 );
 494                                 if (setreuid( -1, pwd->pw_uid ) == -1) {
 495                                         setreuid( -1, 0 );
 496                                         setreuid( 0, -1 );
 497                                         if(setreuid( -1, pwd->pw_uid ) == -1)
 498                                                 return PAM_CRED_INSUFFICIENT;
 499                                 }
 500                         }
 501
 502                         spwdent = getspnam( name );
 503                         if (save_uid == pwd->pw_uid)
 504                                 setreuid( save_uid, save_euid );
 505                         else {
 506                                 if (setreuid( -1, 0 ) == -1)
 507                                 setreuid( save_uid, -1 );
 508                                 setreuid( -1, save_euid );
 509                         }
 510                 } else if (strcmp(pwd->pw_passwd, "x") == 0) {
 511                         /*
 512                          * ...and shadow password file entry for this user,
 513                          * if shadowing is enabled
 514                          */
 515                         spwdent = getspnam(name);
 516                 }
 517                 if (spwdent)
 518                         salt = x_strdup(spwdent->sp_pwdp);
 519                 else
 520                         salt = x_strdup(pwd->pw_passwd);
 521         }
 522
 523         data_name = (char *) malloc(sizeof(FAIL_PREFIX) + strlen(name));
 524         if (data_name == NULL) {
 525                 _log_err(LOG_CRIT, pamh, "no memory for data-name");
 526         } else {
 527                 strcpy(data_name, FAIL_PREFIX);
 528                 strcpy(data_name + sizeof(FAIL_PREFIX) - 1, name);
 529         }
 530
 531         retval = PAM_SUCCESS;
 532         if (pwd == NULL || salt == NULL || !strcmp(salt, "x")) {
 533                 if (geteuid()) {
 534                         /* we are not root perhaps this is the reason? Run helper */
 535                         D(("running helper binary"));
 536                         retval = _unix_run_helper_binary(pamh, p, ctrl, name);
 537                         if (pwd == NULL && !on(UNIX_AUDIT,ctrl)
 538                             && retval != PAM_SUCCESS)
 539                         {
 540                                 name = NULL;
 541                         }
 542                 } else {
 543                         D(("user's record unavailable"));
 544                         if (on(UNIX_AUDIT, ctrl)) {
 545                                 /* this might be a typo and the user has given a password
 546                                    instead of a username. Careful with this. */
 547                                 _log_err(LOG_ALERT, pamh,
 548                                          "check pass; user (%s) unknown", name);
 549                         } else {
 550                                 name = NULL;
 551                                 _log_err(LOG_ALERT, pamh,
 552                                          "check pass; user unknown");
 553                         }
 554                         p = NULL;
 555                         retval = PAM_AUTHINFO_UNAVAIL;
 556                 }
 557         } else {
 558                 if (!strlen(salt)) {
 559                         /* the stored password is NULL */
 560                         if (off(UNIX__NONULL, ctrl)) {  /* this means we've succeeded */
 561                                 D(("user has empty password - access granted"));
 562                                 retval = PAM_SUCCESS;
 563                         } else {
 564                                 D(("user has empty password - access denied"));
 565                                 retval = PAM_AUTH_ERR;
 566                         }
 567                 } else if (!p) {
 568                                 retval = PAM_AUTH_ERR;
 569                 } else {
 570                         if (!strncmp(salt, "$1$", 3)) {
 571                                 pp = Goodcrypt_md5(p, salt);
 572                                 if (strcmp(pp, salt) != 0) {
 573                                         pp = Brokencrypt_md5(p, salt);
 574                                 }
 575                         } else {
 576                                 pp = bigcrypt(p, salt);
 577                         }
 578                         p = NULL;               /* no longer needed here */
 579
 580                         /* the moment of truth -- do we agree with the password? */
 581                         D(("comparing state of pp[%s] and salt[%s]", pp, salt));
 582
 583                         if (strcmp(pp, salt) == 0) {
 584                                 retval = PAM_SUCCESS;
 585                         } else {
 586                                 retval = PAM_AUTH_ERR;
 587                         }
 588                 }
 589         }
 590
 591         if (retval == PAM_SUCCESS) {
 592                 if (data_name)  /* reset failures */
 593                         pam_set_data(pamh, data_name, NULL, _cleanup_failures);
 594         } else {
 595                 if (data_name != NULL) {
 596                         struct _pam_failed_auth *new = NULL;
 597                         const struct _pam_failed_auth *old = NULL;
 598
 599                         /* get a failure recorder */
 600
 601                         new = (struct _pam_failed_auth *)
 602                             malloc(sizeof(struct _pam_failed_auth));
 603
 604                         if (new != NULL) {
 605
 606                                 new->user = x_strdup(name ? name : "");
 607                                 new->uid = getuid();
 608                                 new->euid = geteuid();
 609                                 new->name = x_strdup(PAM_getlogin()? PAM_getlogin() : "");
 610
 611                                 /* any previous failures for this user ? */
 612                                 pam_get_data(pamh, data_name, (const void **) &old);
 613
 614                                 if (old != NULL) {
 615                                         new->count = old->count + 1;
 616                                         if (new->count >= UNIX_MAX_RETRIES) {
 617                                                 retval = PAM_MAXTRIES;
 618                                         }
 619                                 } else {
 620                                         const char *service=NULL;
 621                                         const char *ruser=NULL;
 622                                         const char *rhost=NULL;
 623                                         const char *tty=NULL;
 624
 625                                         (void) pam_get_item(pamh, PAM_SERVICE,
 626                                                             (const void **)&service);
 627                                         (void) pam_get_item(pamh, PAM_RUSER,
 628                                                             (const void **)&ruser);
 629                                         (void) pam_get_item(pamh, PAM_RHOST,
 630                                                             (const void **)&rhost);
 631                                         (void) pam_get_item(pamh, PAM_TTY,
 632                                                             (const void **)&tty);
 633
 634                                         _log_err(LOG_NOTICE, pamh,
 635                                                  "authentication failure; "
 636                                                  "logname=%s uid=%d euid=%d "
 637                                                  "tty=%s ruser=%s rhost=%s "
 638                                                  "%s%s",
 639                                                  new->name, new->uid, new->euid,
 640                                                  tty ? tty : "",
 641                                                  ruser ? ruser : "",
 642                                                  rhost ? rhost : "",
 643                                                  (new->user && new->user[0] != '\0')
 644                                                   ? " user=" : "",
 645                                                  new->user
 646                                         );
 647                                         new->count = 1;
 648                                 }
 649
 650                                 pam_set_data(pamh, data_name, new, _cleanup_failures);
 651
 652                         } else {
 653                                 _log_err(LOG_CRIT, pamh,
 654                                          "no memory for failure recorder");
 655                         }
 656                 }
 657         }
 658
 659         if (data_name)
 660                 _pam_delete(data_name);
 661         if (salt)
 662                 _pam_delete(salt);
 663         if (pp)
 664                 _pam_overwrite(pp);
 665
 666         D(("done [%d].", retval));
 667
 668         return retval;
 669 }
 670
 671 /*
 672  * obtain a password from the user
 673  */
 674
 675 int _unix_read_password(pam_handle_t * pamh
 676                         ,unsigned int ctrl
 677                         ,const char *comment
 678                         ,const char *prompt1
 679                         ,const char *prompt2
 680                         ,const char *data_name
 681                         ,const char **pass)
 682 {
 683         int authtok_flag;
 684         int retval;
 685         const char *item;
 686         char *token;
 687
 688         D(("called"));
 689
 690         /*
 691          * make sure nothing inappropriate gets returned
 692          */
 693
 694         *pass = token = NULL;
 695
 696         /*
 697          * which authentication token are we getting?
 698          */
 699
 700         authtok_flag = on(UNIX__OLD_PASSWD, ctrl) ? PAM_OLDAUTHTOK : PAM_AUTHTOK;
 701
 702         /*
 703          * should we obtain the password from a PAM item ?
 704          */
 705
 706         if (on(UNIX_TRY_FIRST_PASS, ctrl) || on(UNIX_USE_FIRST_PASS, ctrl)) {
 707                 retval = pam_get_item(pamh, authtok_flag, (const void **) &item);
 708                 if (retval != PAM_SUCCESS) {
 709                         /* very strange. */
 710                         _log_err(LOG_ALERT, pamh
 711                                  ,"pam_get_item returned error to unix-read-password"
 712                             );
 713                         return retval;
 714                 } else if (item != NULL) {      /* we have a password! */
 715                         *pass = item;
 716                         item = NULL;
 717                         return PAM_SUCCESS;
 718                 } else if (on(UNIX_USE_FIRST_PASS, ctrl)) {
 719                         return PAM_AUTHTOK_RECOVER_ERR;         /* didn't work */
 720                 } else if (on(UNIX_USE_AUTHTOK, ctrl)
 721                            && off(UNIX__OLD_PASSWD, ctrl)) {
 722                         return PAM_AUTHTOK_RECOVER_ERR;
 723                 }
 724         }
 725         /*
 726          * getting here implies we will have to get the password from the
 727          * user directly.
 728          */
 729
 730         {
 731                 struct pam_message msg[3], *pmsg[3];
 732                 struct pam_response *resp;
 733                 int i, replies;
 734
 735                 /* prepare to converse */
 736
 737                 if (comment != NULL && off(UNIX__QUIET, ctrl)) {
 738                         pmsg[0] = &msg[0];
 739                         msg[0].msg_style = PAM_TEXT_INFO;
 740                         msg[0].msg = comment;
 741                         i = 1;
 742                 } else {
 743                         i = 0;
 744                 }
 745
 746                 pmsg[i] = &msg[i];
 747                 msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
 748                 msg[i++].msg = prompt1;
 749                 replies = 1;
 750
 751                 if (prompt2 != NULL) {
 752                         pmsg[i] = &msg[i];
 753                         msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
 754                         msg[i++].msg = prompt2;
 755                         ++replies;
 756                 }
 757                 /* so call the conversation expecting i responses */
 758                 resp = NULL;
 759                 retval = converse(pamh, ctrl, i, pmsg, &resp);
 760
 761                 if (resp != NULL) {
 762
 763                         /* interpret the response */
 764
 765                         if (retval == PAM_SUCCESS) {    /* a good conversation */
 766
 767                                 token = x_strdup(resp[i - replies].resp);
 768                                 if (token != NULL) {
 769                                         if (replies == 2) {
 770
 771                                                 /* verify that password entered correctly */
 772                                                 if (!resp[i - 1].resp
 773                                                     || strcmp(token, resp[i - 1].resp)) {
 774                                                         _pam_delete(token);     /* mistyped */
 775                                                         retval = PAM_AUTHTOK_RECOVER_ERR;
 776                                                         _make_remark(pamh, ctrl
 777                                                                     ,PAM_ERROR_MSG, MISTYPED_PASS);
 778                                                 }
 779                                         }
 780                                 } else {
 781                                         _log_err(LOG_NOTICE, pamh
 782                                                  ,"could not recover authentication token");
 783                                 }
 784
 785                         }
 786                         /*
 787                          * tidy up the conversation (resp_retcode) is ignored
 788                          * -- what is it for anyway? AGM
 789                          */
 790
 791                         _pam_drop_reply(resp, i);
 792
 793                 } else {
 794                         retval = (retval == PAM_SUCCESS)
 795                             ? PAM_AUTHTOK_RECOVER_ERR : retval;
 796                 }
 797         }
 798
 799         if (retval != PAM_SUCCESS) {
 800                 if (on(UNIX_DEBUG, ctrl))
 801                         _log_err(LOG_DEBUG, pamh,
 802                                  "unable to obtain a password");
 803                 return retval;
 804         }
 805         /* 'token' is the entered password */
 806
 807         if (off(UNIX_NOT_SET_PASS, ctrl)) {
 808
 809                 /* we store this password as an item */
 810
 811                 retval = pam_set_item(pamh, authtok_flag, token);
 812                 _pam_delete(token);     /* clean it up */
 813                 if (retval != PAM_SUCCESS
 814                     || (retval = pam_get_item(pamh, authtok_flag
 815                                               ,(const void **) &item))
 816                     != PAM_SUCCESS) {
 817
 818                         _log_err(LOG_CRIT, pamh, "error manipulating password");
 819                         return retval;
 820
 821                 }
 822         } else {
 823                 /*
 824                  * then store it as data specific to this module. pam_end()
 825                  * will arrange to clean it up.
 826                  */
 827
 828                 retval = pam_set_data(pamh, data_name, (void *) token, _cleanup);
 829                 if (retval != PAM_SUCCESS) {
 830                         _log_err(LOG_CRIT, pamh
 831                                  ,"error manipulating password data [%s]"
 832                                  ,pam_strerror(pamh, retval));
 833                         _pam_delete(token);
 834                         return retval;
 835                 }
 836                 item = token;
 837                 token = NULL;   /* break link to password */
 838         }
 839
 840         *pass = item;
 841         item = NULL;            /* break link to password */
 842
 843         return PAM_SUCCESS;
 844 }
 845
 846 /* ****************************************************************** *
 847  * Copyright (c) Jan Rêkorajski 1999.
 848  * Copyright (c) Andrew G. Morgan 1996-8.
 849  * Copyright (c) Alex O. Yuriev, 1996.
 850  * Copyright (c) Cristian Gafton 1996.
 851  *
 852  * Redistribution and use in source and binary forms, with or without
 853  * modification, are permitted provided that the following conditions
 854  * are met:
 855  * 1. Redistributions of source code must retain the above copyright
 856  *    notice, and the entire permission notice in its entirety,
 857  *    including the disclaimer of warranties.
 858  * 2. Redistributions in binary form must reproduce the above copyright
 859  *    notice, this list of conditions and the following disclaimer in the
 860  *    documentation and/or other materials provided with the distribution.
 861  * 3. The name of the author may not be used to endorse or promote
 862  *    products derived from this software without specific prior
 863  *    written permission.
 864  *
 865  * ALTERNATIVELY, this product may be distributed under the terms of
 866  * the GNU Public License, in which case the provisions of the GPL are
 867  * required INSTEAD OF the above restrictions.  (This clause is
 868  * necessary due to a potential bad interaction between the GPL and
 869  * the restrictions contained in a BSD-style copyright.)
 870  *
 871  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 872  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 873  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 874  * DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
 875  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 876  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 877  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 878  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 879  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 880  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 881  * OF THE POSSIBILITY OF SUCH DAMAGE.
 882  */