pam_krb5.c revision 96444
1/*- 2 * Copyright 2001 Mark R V Murray 3 * Copyright Frank Cusack fcusack@fcusack.com 1999-2000 4 * All rights reserved 5 * Copyright (c) 2002 Networks Associates Technology, Inc. 6 * All rights reserved. 7 * 8 * Portions of this software were developed for the FreeBSD Project by 9 * ThinkSec AS and NAI Labs, the Security Research Division of Network 10 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 11 * ("CBOSS"), as part of the DARPA CHATS research program. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, and the entire permission notice in its entirety, 18 * including the disclaimer of warranties. 19 * 2. Redistributions in binary form must reproduce the above copyright 20 * notice, this list of conditions and the following disclaimer in the 21 * documentation and/or other materials provided with the distribution. 22 * 3. The name of the author may not be used to endorse or promote 23 * products derived from this software without specific prior 24 * written permission. 25 * 26 * ALTERNATIVELY, this product may be distributed under the terms of 27 * the GNU Public License, in which case the provisions of the GPL are 28 * required INSTEAD OF the above restrictions. (This clause is 29 * necessary due to a potential bad interaction between the GPL and 30 * the restrictions contained in a BSD-style copyright.) 31 * 32 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED 33 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 34 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 35 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 36 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 37 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 38 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 40 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 41 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 42 * OF THE POSSIBILITY OF SUCH DAMAGE. 43 * --------------------------------------------------------------------------- 44 * 45 * This software may contain code from Naomaru Itoi: 46 * 47 * PAM-kerberos5 module Copyright notice. 48 * Naomaru Itoi <itoi@eecs.umich.edu>, June 24, 1997. 49 * 50 * ---------------------------------------------------------------------------- 51 * COPYRIGHT (c) 1997 52 * THE REGENTS OF THE UNIVERSITY OF MICHIGAN 53 * ALL RIGHTS RESERVED 54 * 55 * PERMISSION IS GRANTED TO USE, COPY, CREATE DERIVATIVE WORKS AND REDISTRIBUTE 56 * THIS SOFTWARE AND SUCH DERIVATIVE WORKS FOR ANY PURPOSE, SO LONG AS THE NAME 57 * OF THE UNIVERSITY OF MICHIGAN IS NOT USED IN ANY ADVERTISING OR PUBLICITY 58 * PERTAINING TO THE USE OR DISTRIBUTION OF THIS SOFTWARE WITHOUT SPECIFIC, 59 * WRITTEN PRIOR AUTHORIZATION. IF THE ABOVE COPYRIGHT NOTICE OR ANY OTHER 60 * IDENTIFICATION OF THE UNIVERSITY OF MICHIGAN IS INCLUDED IN ANY COPY OF ANY 61 * PORTION OF THIS SOFTWARE, THEN THE DISCLAIMER BELOW MUST ALSO BE INCLUDED. 62 * 63 * THE SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION FROM THE UNIVERSITY OF 64 * MICHIGAN AS TO ITS FITNESS FOR ANY PURPOSE, AND WITHOUT WARRANTY BY THE 65 * UNIVERSITY OF MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING 66 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF MERCHANTABITILY AND FITNESS FOR A 67 * PARTICULAR PURPOSE. THE REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE 68 * LIABLE FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR 69 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING OUT OF OR IN 70 * CONNECTION WITH THE USE OF THE SOFTWARE, EVEN IF IT HAS BEEN OR IS HEREAFTER 71 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. 72 * 73 * PAM-kerberos5 module is written based on PAM-kerberos4 module 74 * by Derrick J. Brashear and kerberos5-1.0pl1 by M.I.T. kerberos team. 75 * Permission to use, copy, modify, distribute this software is hereby 76 * granted, as long as it is granted by Derrick J. Brashear and 77 * M.I.T. kerberos team. Followings are their copyright information. 78 * ---------------------------------------------------------------------------- 79 * 80 * This software may contain code from Derrick J. Brashear: 81 * 82 * 83 * Copyright (c) Derrick J. Brashear, 1996. All rights reserved 84 * 85 * Redistribution and use in source and binary forms, with or without 86 * modification, are permitted provided that the following conditions 87 * are met: 88 * 1. Redistributions of source code must retain the above copyright 89 * notice, and the entire permission notice in its entirety, 90 * including the disclaimer of warranties. 91 * 2. Redistributions in binary form must reproduce the above copyright 92 * notice, this list of conditions and the following disclaimer in the 93 * documentation and/or other materials provided with the distribution. 94 * 3. The name of the author may not be used to endorse or promote 95 * products derived from this software without specific prior 96 * written permission. 97 * 98 * ALTERNATIVELY, this product may be distributed under the terms of 99 * the GNU Public License, in which case the provisions of the GPL are 100 * required INSTEAD OF the above restrictions. (This clause is 101 * necessary due to a potential bad interaction between the GPL and 102 * the restrictions contained in a BSD-style copyright.) 103 * 104 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED 105 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 106 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 107 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 108 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 109 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 110 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 111 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 112 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 113 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 114 * OF THE POSSIBILITY OF SUCH DAMAGE. 115 * 116 * ---------------------------------------------------------------------------- 117 * 118 * This software may contain code from MIT Kerberos 5: 119 * 120 * Copyright Notice and Legal Administrivia 121 * ---------------------------------------- 122 * 123 * Copyright (C) 1996 by the Massachusetts Institute of Technology. 124 * 125 * All rights reserved. 126 * 127 * Export of this software from the United States of America may require 128 * a specific license from the United States Government. It is the 129 * responsibility of any person or organization contemplating export to 130 * obtain such a license before exporting. 131 * 132 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 133 * distribute this software and its documentation for any purpose and 134 * without fee is hereby granted, provided that the above copyright 135 * notice appear in all copies and that both that copyright notice and 136 * this permission notice appear in supporting documentation, and that 137 * the name of M.I.T. not be used in advertising or publicity pertaining 138 * to distribution of the software without specific, written prior 139 * permission. M.I.T. makes no representations about the suitability of 140 * this software for any purpose. It is provided "as is" without express 141 * or implied warranty. 142 * 143 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 144 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 145 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 146 * 147 * Individual source code files are copyright MIT, Cygnus Support, 148 * OpenVision, Oracle, Sun Soft, and others. 149 * 150 * Project Athena, Athena, Athena MUSE, Discuss, Hesiod, Kerberos, Moira, 151 * and Zephyr are trademarks of the Massachusetts Institute of Technology 152 * (MIT). No commercial use of these trademarks may be made without 153 * prior written permission of MIT. 154 * 155 * "Commercial use" means use of a name in a product or other for-profit 156 * manner. It does NOT prevent a commercial firm from referring to the 157 * MIT trademarks in order to convey information (although in doing so, 158 * recognition of their trademark status should be given). 159 * 160 * The following copyright and permission notice applies to the 161 * OpenVision Kerberos Administration system located in kadmin/create, 162 * kadmin/dbutil, kadmin/passwd, kadmin/server, lib/kadm5, and portions 163 * of lib/rpc: 164 * 165 * Copyright, OpenVision Technologies, Inc., 1996, All Rights Reserved 166 * 167 * WARNING: Retrieving the OpenVision Kerberos Administration system 168 * source code, as described below, indicates your acceptance of the 169 * following terms. If you do not agree to the following terms, do not 170 * retrieve the OpenVision Kerberos administration system. 171 * 172 * You may freely use and distribute the Source Code and Object Code 173 * compiled from it, with or without modification, but this Source 174 * Code is provided to you "AS IS" EXCLUSIVE OF ANY WARRANTY, 175 * INCLUDING, WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY OR 176 * FITNESS FOR A PARTICULAR PURPOSE, OR ANY OTHER WARRANTY, WHETHER 177 * EXPRESS OR IMPLIED. IN NO EVENT WILL OPENVISION HAVE ANY LIABILITY 178 * FOR ANY LOST PROFITS, LOSS OF DATA OR COSTS OF PROCUREMENT OF 179 * SUBSTITUTE GOODS OR SERVICES, OR FOR ANY SPECIAL, INDIRECT, OR 180 * CONSEQUENTIAL DAMAGES ARISING OUT OF THIS AGREEMENT, INCLUDING, 181 * WITHOUT LIMITATION, THOSE RESULTING FROM THE USE OF THE SOURCE 182 * CODE, OR THE FAILURE OF THE SOURCE CODE TO PERFORM, OR FOR ANY 183 * OTHER REASON. 184 * 185 * OpenVision retains all copyrights in the donated Source Code. OpenVision 186 * also retains copyright to derivative works of the Source Code, whether 187 * created by OpenVision or by a third party. The OpenVision copyright 188 * notice must be preserved if derivative works are made based on the 189 * donated Source Code. 190 * 191 * OpenVision Technologies, Inc. has donated this Kerberos 192 * Administration system to MIT for inclusion in the standard 193 * Kerberos 5 distribution. This donation underscores our 194 * commitment to continuing Kerberos technology development 195 * and our gratitude for the valuable work which has been 196 * performed by MIT and the Kerberos community. 197 * 198 */ 199 200#include <sys/cdefs.h> 201__FBSDID("$FreeBSD: head/lib/libpam/modules/pam_krb5/pam_krb5.c 96444 2002-05-12 07:06:27Z des $"); 202 203#include <sys/types.h> 204#include <sys/stat.h> 205#include <errno.h> 206#include <limits.h> 207#include <pwd.h> 208#include <stdio.h> 209#include <stdlib.h> 210#include <string.h> 211#include <syslog.h> 212#include <unistd.h> 213 214#include <krb5.h> 215#include <com_err.h> 216 217#define PAM_SM_AUTH 218#define PAM_SM_ACCOUNT 219#define PAM_SM_PASSWORD 220 221#include <security/pam_appl.h> 222#include <security/pam_modules.h> 223#include <security/pam_mod_misc.h> 224 225#define COMPAT_HEIMDAL 226/* #define COMPAT_MIT */ 227 228static int verify_krb_v5_tgt(krb5_context, krb5_ccache, char *, int); 229static void cleanup_cache(pam_handle_t *, void *, int); 230static const char *compat_princ_component(krb5_context, krb5_principal, int); 231static void compat_free_data_contents(krb5_context, krb5_data *); 232 233#define USER_PROMPT "Username: " 234#define PASSWORD_PROMPT "Password:" 235#define NEW_PASSWORD_PROMPT "New Password:" 236 237enum { 238 PAM_OPT_AUTH_AS_SELF = PAM_OPT_STD_MAX, 239 PAM_OPT_CCACHE, 240 PAM_OPT_FORWARDABLE, 241 PAM_OPT_NO_CCACHE, 242 PAM_OPT_REUSE_CCACHE 243}; 244 245static struct opttab other_options[] = { 246 { "auth_as_self", PAM_OPT_AUTH_AS_SELF }, 247 { "ccache", PAM_OPT_CCACHE }, 248 { "forwardable", PAM_OPT_FORWARDABLE }, 249 { "no_ccache", PAM_OPT_NO_CCACHE }, 250 { "reuse_ccache", PAM_OPT_REUSE_CCACHE }, 251 { NULL, 0 } 252}; 253 254/* 255 * authentication management 256 */ 257PAM_EXTERN int 258pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 259 int argc, const char *argv[]) 260{ 261 krb5_error_code krbret; 262 krb5_context pam_context; 263 krb5_creds creds; 264 krb5_principal princ; 265 krb5_ccache ccache, ccache_check; 266 krb5_get_init_creds_opt opts; 267 struct options options; 268 struct passwd *pwd; 269 int retval; 270 const char *sourceuser, *user, *pass, *service; 271 char *principal, *princ_name, *cache_name, luser[32], *srvdup; 272 273 pam_std_option(&options, other_options, argc, argv); 274 275 PAM_LOG("Options processed"); 276 277 retval = pam_get_user(pamh, &user, USER_PROMPT); 278 if (retval != PAM_SUCCESS) 279 return (retval); 280 281 PAM_LOG("Got user: %s", user); 282 283 retval = pam_get_item(pamh, PAM_RUSER, (const void **)&sourceuser); 284 if (retval != PAM_SUCCESS) 285 return (retval); 286 287 PAM_LOG("Got ruser: %s", sourceuser); 288 289 service = NULL; 290 pam_get_item(pamh, PAM_SERVICE, (const void **)&service); 291 if (service == NULL) 292 service = "unknown"; 293 294 PAM_LOG("Got service: %s", service); 295 296 krbret = krb5_init_context(&pam_context); 297 if (krbret != 0) { 298 PAM_VERBOSE_ERROR("Kerberos 5 error"); 299 return (PAM_SERVICE_ERR); 300 } 301 302 PAM_LOG("Context initialised"); 303 304 krb5_get_init_creds_opt_init(&opts); 305 306 if (pam_test_option(&options, PAM_OPT_FORWARDABLE, NULL)) 307 krb5_get_init_creds_opt_set_forwardable(&opts, 1); 308 309 PAM_LOG("Credentials initialised"); 310 311 krbret = krb5_cc_register(pam_context, &krb5_mcc_ops, FALSE); 312 if (krbret != 0 && krbret != KRB5_CC_TYPE_EXISTS) { 313 PAM_VERBOSE_ERROR("Kerberos 5 error"); 314 retval = PAM_SERVICE_ERR; 315 goto cleanup3; 316 } 317 318 PAM_LOG("Done krb5_cc_register()"); 319 320 /* Get principal name */ 321 if (pam_test_option(&options, PAM_OPT_AUTH_AS_SELF, NULL)) 322 asprintf(&principal, "%s/%s", sourceuser, user); 323 else 324 principal = strdup(user); 325 326 PAM_LOG("Created principal: %s", principal); 327 328 krbret = krb5_parse_name(pam_context, principal, &princ); 329 free(principal); 330 if (krbret != 0) { 331 PAM_LOG("Error krb5_parse_name(): %s", error_message(krbret)); 332 PAM_VERBOSE_ERROR("Kerberos 5 error"); 333 retval = PAM_SERVICE_ERR; 334 goto cleanup3; 335 } 336 337 PAM_LOG("Done krb5_parse_name()"); 338 339 /* Now convert the principal name into something human readable */ 340 princ_name = NULL; 341 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 342 if (krbret != 0) { 343 PAM_LOG("Error krb5_unparse_name(): %s", error_message(krbret)); 344 PAM_VERBOSE_ERROR("Kerberos 5 error"); 345 retval = PAM_SERVICE_ERR; 346 goto cleanup2; 347 } 348 349 PAM_LOG("Got principal: %s", princ_name); 350 351 /* Get password */ 352 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT); 353 if (retval != PAM_SUCCESS) 354 goto cleanup2; 355 356 PAM_LOG("Got password"); 357 358 /* Verify the local user exists (AFTER getting the password) */ 359 if (strchr(user, '@')) { 360 /* get a local account name for this principal */ 361 krbret = krb5_aname_to_localname(pam_context, princ, 362 sizeof(luser), luser); 363 if (krbret != 0) { 364 PAM_VERBOSE_ERROR("Kerberos 5 error"); 365 PAM_LOG("Error krb5_aname_to_localname(): %s", 366 error_message(krbret)); 367 retval = PAM_USER_UNKNOWN; 368 goto cleanup2; 369 } 370 371 retval = pam_set_item(pamh, PAM_USER, luser); 372 if (retval != PAM_SUCCESS) 373 goto cleanup2; 374 375 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 376 if (retval != PAM_SUCCESS) 377 goto cleanup2; 378 379 PAM_LOG("PAM_USER Redone"); 380 } 381 382 pwd = getpwnam(user); 383 if (pwd == NULL) { 384 retval = PAM_USER_UNKNOWN; 385 goto cleanup2; 386 } 387 388 PAM_LOG("Done getpwnam()"); 389 390 /* Get a TGT */ 391 memset(&creds, 0, sizeof(krb5_creds)); 392 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 393 pass, NULL, pamh, 0, NULL, &opts); 394 if (krbret != 0) { 395 PAM_VERBOSE_ERROR("Kerberos 5 error"); 396 PAM_LOG("Error krb5_get_init_creds_password(): %s", 397 error_message(krbret)); 398 retval = PAM_AUTH_ERR; 399 goto cleanup2; 400 } 401 402 PAM_LOG("Got TGT"); 403 404 /* Generate a unique cache_name */ 405 asprintf(&cache_name, "MEMORY:/tmp/%s.%d", service, getpid()); 406 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache); 407 free(cache_name); 408 if (krbret != 0) { 409 PAM_VERBOSE_ERROR("Kerberos 5 error"); 410 PAM_LOG("Error krb5_cc_resolve(): %s", error_message(krbret)); 411 retval = PAM_SERVICE_ERR; 412 goto cleanup; 413 } 414 krbret = krb5_cc_initialize(pam_context, ccache, princ); 415 if (krbret != 0) { 416 PAM_VERBOSE_ERROR("Kerberos 5 error"); 417 PAM_LOG("Error krb5_cc_initialize(): %s", error_message(krbret)); 418 retval = PAM_SERVICE_ERR; 419 goto cleanup; 420 } 421 krbret = krb5_cc_store_cred(pam_context, ccache, &creds); 422 if (krbret != 0) { 423 PAM_VERBOSE_ERROR("Kerberos 5 error"); 424 PAM_LOG("Error krb5_cc_store_cred(): %s", error_message(krbret)); 425 krb5_cc_destroy(pam_context, ccache); 426 retval = PAM_SERVICE_ERR; 427 goto cleanup; 428 } 429 430 PAM_LOG("Credentials stashed"); 431 432 /* Verify them */ 433 if ((srvdup = strdup(service)) == NULL) { 434 retval = PAM_BUF_ERR; 435 goto cleanup; 436 } 437 krbret = verify_krb_v5_tgt(pam_context, ccache, srvdup, 438 pam_test_option(&options, PAM_OPT_FORWARDABLE, NULL)); 439 free(srvdup); 440 if (krbret == -1) { 441 PAM_VERBOSE_ERROR("Kerberos 5 error"); 442 krb5_cc_destroy(pam_context, ccache); 443 retval = PAM_AUTH_ERR; 444 goto cleanup; 445 } 446 447 PAM_LOG("Credentials stash verified"); 448 449 retval = pam_get_data(pamh, "ccache", (const void **)&ccache_check); 450 if (retval == PAM_SUCCESS) { 451 krb5_cc_destroy(pam_context, ccache); 452 PAM_VERBOSE_ERROR("Kerberos 5 error"); 453 retval = PAM_AUTH_ERR; 454 goto cleanup; 455 } 456 457 PAM_LOG("Credentials stash not pre-existing"); 458 459 retval = pam_set_data(pamh, "ccache", ccache, cleanup_cache); 460 if (retval != 0) { 461 krb5_cc_destroy(pam_context, ccache); 462 PAM_VERBOSE_ERROR("Kerberos 5 error"); 463 retval = PAM_SERVICE_ERR; 464 goto cleanup; 465 } 466 467 PAM_LOG("Credentials stash saved"); 468 469cleanup: 470 krb5_free_cred_contents(pam_context, &creds); 471 PAM_LOG("Done cleanup"); 472cleanup2: 473 krb5_free_principal(pam_context, princ); 474 PAM_LOG("Done cleanup2"); 475cleanup3: 476 if (princ_name) 477 free(princ_name); 478 479 krb5_free_context(pam_context); 480 481 PAM_LOG("Done cleanup3"); 482 483 if (retval != PAM_SUCCESS) 484 PAM_VERBOSE_ERROR("Kerberos 5 refuses you"); 485 486 return (retval); 487} 488 489PAM_EXTERN int 490pam_sm_setcred(pam_handle_t *pamh, int flags, 491 int argc, const char *argv[]) 492{ 493 494 krb5_error_code krbret; 495 krb5_context pam_context; 496 krb5_principal princ; 497 krb5_creds creds; 498 krb5_ccache ccache_temp, ccache_perm; 499 krb5_cc_cursor cursor; 500 struct options options; 501 struct passwd *pwd = NULL; 502 int retval; 503 char *user; 504 char *cache_name, *cache_env_name, *p, *q; 505 506 uid_t euid; 507 gid_t egid; 508 509 pam_std_option(&options, other_options, argc, argv); 510 511 PAM_LOG("Options processed"); 512 513 if (flags & PAM_DELETE_CRED) 514 return (PAM_SUCCESS); 515 516 if (flags & PAM_REFRESH_CRED) 517 return (PAM_SUCCESS); 518 519 if (flags & PAM_REINITIALIZE_CRED) 520 return (PAM_SUCCESS); 521 522 if (!(flags & PAM_ESTABLISH_CRED)) 523 return (PAM_SERVICE_ERR); 524 525 PAM_LOG("Establishing credentials"); 526 527 /* Get username */ 528 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 529 if (retval != PAM_SUCCESS) 530 return (retval); 531 532 PAM_LOG("Got user: %s", user); 533 534 krbret = krb5_init_context(&pam_context); 535 if (krbret != 0) { 536 PAM_LOG("Error krb5_init_context(): %s", error_message(krbret)); 537 return (PAM_SERVICE_ERR); 538 } 539 540 PAM_LOG("Context initialised"); 541 542 euid = geteuid(); /* Usually 0 */ 543 egid = getegid(); 544 545 PAM_LOG("Got euid, egid: %d %d", euid, egid); 546 547 /* Retrieve the cache name */ 548 retval = pam_get_data(pamh, "ccache", (const void **)&ccache_temp); 549 if (retval != PAM_SUCCESS) 550 goto cleanup3; 551 552 /* Get the uid. This should exist. */ 553 pwd = getpwnam(user); 554 if (pwd == NULL) { 555 retval = PAM_USER_UNKNOWN; 556 goto cleanup3; 557 } 558 559 PAM_LOG("Done getpwnam()"); 560 561 /* Avoid following a symlink as root */ 562 if (setegid(pwd->pw_gid)) { 563 retval = PAM_SERVICE_ERR; 564 goto cleanup3; 565 } 566 if (seteuid(pwd->pw_uid)) { 567 retval = PAM_SERVICE_ERR; 568 goto cleanup3; 569 } 570 571 PAM_LOG("Done setegid() & seteuid()"); 572 573 /* Get the cache name */ 574 cache_name = NULL; 575 pam_test_option(&options, PAM_OPT_CCACHE, &cache_name); 576 if (cache_name == NULL) 577 asprintf(&cache_name, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 578 579 p = calloc(PATH_MAX + 16, sizeof(char)); 580 q = cache_name; 581 582 if (p == NULL) { 583 PAM_LOG("Error malloc(): failure"); 584 retval = PAM_BUF_ERR; 585 goto cleanup3; 586 } 587 cache_name = p; 588 589 /* convert %u and %p */ 590 while (*q) { 591 if (*q == '%') { 592 q++; 593 if (*q == 'u') { 594 sprintf(p, "%d", pwd->pw_uid); 595 p += strlen(p); 596 } 597 else if (*q == 'p') { 598 sprintf(p, "%d", getpid()); 599 p += strlen(p); 600 } 601 else { 602 /* Not a special token */ 603 *p++ = '%'; 604 q--; 605 } 606 q++; 607 } 608 else { 609 *p++ = *q++; 610 } 611 } 612 613 PAM_LOG("Got cache_name: %s", cache_name); 614 615 /* Initialize the new ccache */ 616 krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ); 617 if (krbret != 0) { 618 PAM_LOG("Error krb5_cc_get_principal(): %s", 619 error_message(krbret)); 620 retval = PAM_SERVICE_ERR; 621 goto cleanup3; 622 } 623 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm); 624 if (krbret != 0) { 625 PAM_LOG("Error krb5_cc_resolve(): %s", error_message(krbret)); 626 retval = PAM_SERVICE_ERR; 627 goto cleanup2; 628 } 629 krbret = krb5_cc_initialize(pam_context, ccache_perm, princ); 630 if (krbret != 0) { 631 PAM_LOG("Error krb5_cc_initialize(): %s", error_message(krbret)); 632 retval = PAM_SERVICE_ERR; 633 goto cleanup2; 634 } 635 636 PAM_LOG("Cache initialised"); 637 638 /* Prepare for iteration over creds */ 639 krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor); 640 if (krbret != 0) { 641 PAM_LOG("Error krb5_cc_start_seq_get(): %s", error_message(krbret)); 642 krb5_cc_destroy(pam_context, ccache_perm); 643 retval = PAM_SERVICE_ERR; 644 goto cleanup2; 645 } 646 647 PAM_LOG("Prepared for iteration"); 648 649 /* Copy the creds (should be two of them) */ 650 while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp, 651 &cursor, &creds) == 0)) { 652 krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds); 653 if (krbret != 0) { 654 PAM_LOG("Error krb5_cc_store_cred(): %s", 655 error_message(krbret)); 656 krb5_cc_destroy(pam_context, ccache_perm); 657 krb5_free_cred_contents(pam_context, &creds); 658 retval = PAM_SERVICE_ERR; 659 goto cleanup2; 660 } 661 krb5_free_cred_contents(pam_context, &creds); 662 PAM_LOG("Iteration"); 663 } 664 krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor); 665 666 PAM_LOG("Done iterating"); 667 668 if (strstr(cache_name, "FILE:") == cache_name) { 669 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 670 PAM_LOG("Error chown(): %s", strerror(errno)); 671 krb5_cc_destroy(pam_context, ccache_perm); 672 retval = PAM_SERVICE_ERR; 673 goto cleanup2; 674 } 675 PAM_LOG("Done chown()"); 676 677 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 678 PAM_LOG("Error chmod(): %s", strerror(errno)); 679 krb5_cc_destroy(pam_context, ccache_perm); 680 retval = PAM_SERVICE_ERR; 681 goto cleanup2; 682 } 683 PAM_LOG("Done chmod()"); 684 } 685 686 krb5_cc_close(pam_context, ccache_perm); 687 688 PAM_LOG("Cache closed"); 689 690 cache_env_name = malloc(strlen(cache_name) + 12); 691 if (!cache_env_name) { 692 PAM_LOG("Error malloc(): failure"); 693 krb5_cc_destroy(pam_context, ccache_perm); 694 retval = PAM_BUF_ERR; 695 goto cleanup2; 696 } 697 698 sprintf(cache_env_name, "KRB5CCNAME=%s", cache_name); 699 if ((retval = pam_putenv(pamh, cache_env_name)) != 0) { 700 PAM_LOG("Error pam_putenv(): %s", pam_strerror(pamh, retval)); 701 krb5_cc_destroy(pam_context, ccache_perm); 702 retval = PAM_SERVICE_ERR; 703 goto cleanup2; 704 } 705 706 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 707 708cleanup2: 709 krb5_free_principal(pam_context, princ); 710 PAM_LOG("Done cleanup2"); 711cleanup3: 712 krb5_free_context(pam_context); 713 PAM_LOG("Done cleanup3"); 714 715 seteuid(euid); 716 setegid(egid); 717 718 PAM_LOG("Done seteuid() & setegid()"); 719 720 return (retval); 721} 722 723/* 724 * account management 725 */ 726PAM_EXTERN int 727pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 728 int argc, const char *argv[]) 729{ 730 krb5_error_code krbret; 731 krb5_context pam_context; 732 krb5_ccache ccache; 733 krb5_principal princ; 734 struct options options; 735 int retval; 736 const char *user; 737 738 pam_std_option(&options, other_options, argc, argv); 739 740 PAM_LOG("Options processed"); 741 742 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 743 if (retval != PAM_SUCCESS) 744 return (retval); 745 746 PAM_LOG("Got user: %s", user); 747 748 retval = pam_get_data(pamh, "ccache", (const void **)&ccache); 749 if (retval != PAM_SUCCESS) 750 return (PAM_SUCCESS); 751 752 PAM_LOG("Got ccache"); 753 754 krbret = krb5_init_context(&pam_context); 755 if (krbret != 0) { 756 PAM_LOG("Error krb5_init_context(): %s", error_message(krbret)); 757 return (PAM_PERM_DENIED); 758 } 759 760 PAM_LOG("Context initialised"); 761 762 krbret = krb5_cc_get_principal(pam_context, ccache, &princ); 763 if (krbret != 0) { 764 PAM_LOG("Error krb5_cc_get_principal(): %s", error_message(krbret)); 765 retval = PAM_PERM_DENIED;; 766 goto cleanup; 767 } 768 769 PAM_LOG("Got principal"); 770 771 if (krb5_kuserok(pam_context, princ, user)) 772 retval = PAM_SUCCESS; 773 else 774 retval = PAM_PERM_DENIED; 775 krb5_free_principal(pam_context, princ); 776 777 PAM_LOG("Done kuserok()"); 778 779cleanup: 780 krb5_free_context(pam_context); 781 PAM_LOG("Done cleanup"); 782 783 return (retval); 784 785} 786 787/* 788 * password management 789 */ 790PAM_EXTERN int 791pam_sm_chauthtok(pam_handle_t *pamh, int flags, 792 int argc, const char *argv[]) 793{ 794 krb5_error_code krbret; 795 krb5_context pam_context; 796 krb5_creds creds; 797 krb5_principal princ; 798 krb5_get_init_creds_opt opts; 799 krb5_data result_code_string, result_string; 800 struct options options; 801 int result_code, retval; 802 const char *user, *pass; 803 char *princ_name, *passdup; 804 805 pam_std_option(&options, other_options, argc, argv); 806 807 PAM_LOG("Options processed"); 808 809 if (!(flags & PAM_UPDATE_AUTHTOK)) 810 return (PAM_AUTHTOK_ERR); 811 812 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 813 if (retval != PAM_SUCCESS) 814 return (retval); 815 816 PAM_LOG("Got user: %s", user); 817 818 krbret = krb5_init_context(&pam_context); 819 if (krbret != 0) { 820 PAM_LOG("Error krb5_init_context(): %s", error_message(krbret)); 821 return (PAM_SERVICE_ERR); 822 } 823 824 PAM_LOG("Context initialised"); 825 826 krb5_get_init_creds_opt_init(&opts); 827 828 PAM_LOG("Credentials options initialised"); 829 830 /* Get principal name */ 831 krbret = krb5_parse_name(pam_context, user, &princ); 832 if (krbret != 0) { 833 PAM_LOG("Error krb5_parse_name(): %s", error_message(krbret)); 834 retval = PAM_USER_UNKNOWN; 835 goto cleanup3; 836 } 837 838 /* Now convert the principal name into something human readable */ 839 princ_name = NULL; 840 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 841 if (krbret != 0) { 842 PAM_LOG("Error krb5_unparse_name(): %s", error_message(krbret)); 843 retval = PAM_SERVICE_ERR; 844 goto cleanup2; 845 } 846 847 PAM_LOG("Got principal: %s", princ_name); 848 849 /* Get password */ 850 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT); 851 if (retval != PAM_SUCCESS) 852 goto cleanup2; 853 854 PAM_LOG("Got password"); 855 856 memset(&creds, 0, sizeof(krb5_creds)); 857 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 858 pass, NULL, pamh, 0, "kadmin/changepw", &opts); 859 if (krbret != 0) { 860 PAM_LOG("Error krb5_get_init_creds_password()", 861 error_message(krbret)); 862 retval = PAM_AUTH_ERR; 863 goto cleanup2; 864 } 865 866 PAM_LOG("Credentials established"); 867 868 /* Now get the new password */ 869 for (;;) { 870 retval = pam_get_authtok(pamh, 871 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 872 if (retval != PAM_TRY_AGAIN) 873 break; 874 pam_error(pamh, "Mismatch; try again, EOF to quit."); 875 } 876 if (retval != PAM_SUCCESS) 877 goto cleanup; 878 879 PAM_LOG("Got new password"); 880 881 /* Change it */ 882 if ((passdup = strdup(pass)) == NULL) { 883 retval = PAM_BUF_ERR; 884 goto cleanup; 885 } 886 krbret = krb5_change_password(pam_context, &creds, passdup, 887 &result_code, &result_code_string, &result_string); 888 free(passdup); 889 if (krbret != 0) { 890 PAM_LOG("Error krb5_change_password(): %s", 891 error_message(krbret)); 892 retval = PAM_AUTHTOK_ERR; 893 goto cleanup; 894 } 895 if (result_code) { 896 PAM_LOG("Error krb5_change_password(): (result_code)"); 897 retval = PAM_AUTHTOK_ERR; 898 goto cleanup; 899 } 900 901 PAM_LOG("Password changed"); 902 903 if (result_string.data) 904 free(result_string.data); 905 if (result_code_string.data) 906 free(result_code_string.data); 907 908cleanup: 909 krb5_free_cred_contents(pam_context, &creds); 910 PAM_LOG("Done cleanup"); 911cleanup2: 912 krb5_free_principal(pam_context, princ); 913 PAM_LOG("Done cleanup2"); 914cleanup3: 915 if (princ_name) 916 free(princ_name); 917 918 krb5_free_context(pam_context); 919 920 PAM_LOG("Done cleanup3"); 921 922 return (retval); 923} 924 925PAM_MODULE_ENTRY("pam_krb5"); 926 927/* 928 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 929 * Modified by Sam Hartman <hartmans@mit.edu> to support PAM services 930 * for Debian. 931 * 932 * Verify the Kerberos ticket-granting ticket just retrieved for the 933 * user. If the Kerberos server doesn't respond, assume the user is 934 * trying to fake us out (since we DID just get a TGT from what is 935 * supposedly our KDC). If the host/<host> service is unknown (i.e., 936 * the local keytab doesn't have it), and we cannot find another 937 * service we do have, let her in. 938 * 939 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 940 */ 941static int 942verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 943 char *pam_service, int debug) 944{ 945 krb5_error_code retval; 946 krb5_principal princ; 947 krb5_keyblock *keyblock; 948 krb5_data packet; 949 krb5_auth_context auth_context; 950 char phost[BUFSIZ]; 951 const char *services[3], **service; 952 953 packet.data = 0; 954 955 /* If possible we want to try and verify the ticket we have 956 * received against a keytab. We will try multiple service 957 * principals, including at least the host principal and the PAM 958 * service principal. The host principal is preferred because access 959 * to that key is generally sufficient to compromise root, while the 960 * service key for this PAM service may be less carefully guarded. 961 * It is important to check the keytab first before the KDC so we do 962 * not get spoofed by a fake KDC. 963 */ 964 services[0] = "host"; 965 services[1] = pam_service; 966 services[2] = NULL; 967 keyblock = 0; 968 retval = -1; 969 for (service = &services[0]; *service != NULL; service++) { 970 retval = krb5_sname_to_principal(context, NULL, *service, 971 KRB5_NT_SRV_HST, &princ); 972 if (retval != 0) { 973 if (debug) 974 syslog(LOG_DEBUG, "pam_krb5: verify_krb_v5_tgt(): %s: %s", "krb5_sname_to_principal()", error_message(retval)); 975 return -1; 976 } 977 978 /* Extract the name directly. */ 979 strncpy(phost, compat_princ_component(context, princ, 1), 980 BUFSIZ); 981 phost[BUFSIZ - 1] = '\0'; 982 983 /* 984 * Do we have service/<host> keys? 985 * (use default/configured keytab, kvno IGNORE_VNO to get the 986 * first match, and ignore enctype.) 987 */ 988 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 989 &keyblock); 990 if (retval != 0) 991 continue; 992 break; 993 } 994 if (retval != 0) { /* failed to find key */ 995 /* Keytab or service key does not exist */ 996 if (debug) 997 syslog(LOG_DEBUG, "pam_krb5: verify_krb_v5_tgt(): %s: %s", "krb5_kt_read_service_key()", error_message(retval)); 998 retval = 0; 999 goto cleanup; 1000 } 1001 if (keyblock) 1002 krb5_free_keyblock(context, keyblock); 1003 1004 /* Talk to the kdc and construct the ticket. */ 1005 auth_context = NULL; 1006 retval = krb5_mk_req(context, &auth_context, 0, *service, phost, 1007 NULL, ccache, &packet); 1008 if (auth_context) { 1009 krb5_auth_con_free(context, auth_context); 1010 auth_context = NULL; /* setup for rd_req */ 1011 } 1012 if (retval) { 1013 if (debug) 1014 syslog(LOG_DEBUG, "pam_krb5: verify_krb_v5_tgt(): %s: %s", "krb5_mk_req()", error_message(retval)); 1015 retval = -1; 1016 goto cleanup; 1017 } 1018 1019 /* Try to use the ticket. */ 1020 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 1021 NULL, NULL); 1022 if (retval) { 1023 if (debug) 1024 syslog(LOG_DEBUG, "pam_krb5: verify_krb_v5_tgt(): %s: %s", "krb5_rd_req()", error_message(retval)); 1025 retval = -1; 1026 } 1027 else 1028 retval = 1; 1029 1030cleanup: 1031 if (packet.data) 1032 compat_free_data_contents(context, &packet); 1033 krb5_free_principal(context, princ); 1034 return retval; 1035} 1036 1037/* Free the memory for cache_name. Called by pam_end() */ 1038static void 1039cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 1040{ 1041 krb5_context pam_context; 1042 krb5_ccache ccache; 1043 1044 if (krb5_init_context(&pam_context)) 1045 return; 1046 1047 ccache = (krb5_ccache)data; 1048 krb5_cc_destroy(pam_context, ccache); 1049 krb5_free_context(pam_context); 1050} 1051 1052#ifdef COMPAT_HEIMDAL 1053#ifdef COMPAT_MIT 1054#error This cannot be MIT and Heimdal compatible! 1055#endif 1056#endif 1057 1058#ifndef COMPAT_HEIMDAL 1059#ifndef COMPAT_MIT 1060#error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 1061#endif 1062#endif 1063 1064#ifdef COMPAT_HEIMDAL 1065static const char * 1066compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 1067{ 1068 return princ->name.name_string.val[n]; 1069} 1070 1071static void 1072compat_free_data_contents(krb5_context context __unused, krb5_data * data) 1073{ 1074 krb5_xfree(data->data); 1075} 1076#endif 1077 1078#ifdef COMPAT_MIT 1079static const char * 1080compat_princ_component(krb5_context context, krb5_principal princ, int n) 1081{ 1082 return krb5_princ_component(context, princ, n)->data; 1083} 1084 1085static void 1086compat_free_data_contents(krb5_context context, krb5_data * data) 1087{ 1088 krb5_free_data_contents(context, data); 1089} 1090#endif 1091