pam_krb5.c revision 109069
1/*- 2 * This pam_krb5 module contains code that is: 3 * Copyright (c) Derrick J. Brashear, 1996. All rights reserved. 4 * Copyright (c) Frank Cusack, 1999-2001. All rights reserved. 5 * Copyright (c) Jacques A. Vidrine, 2000-2001. All rights reserved. 6 * Copyright (c) Nicolas Williams, 2001. All rights reserved. 7 * Copyright (c) Perot Systems Corporation, 2001. All rights reserved. 8 * Copyright (c) Mark R V Murray, 2001. All rights reserved. 9 * Copyright (c) Networks Associates Technology, Inc., 2002. 10 * All rights reserved. 11 * 12 * Portions of this software were developed for the FreeBSD Project by 13 * ThinkSec AS and NAI Labs, the Security Research Division of Network 14 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 15 * ("CBOSS"), as part of the DARPA CHATS research program. 16 * 17 * Redistribution and use in source and binary forms, with or without 18 * modification, are permitted provided that the following conditions 19 * are met: 20 * 1. Redistributions of source code must retain the above copyright 21 * notices, and the entire permission notice in its entirety, 22 * including the disclaimer of warranties. 23 * 2. Redistributions in binary form must reproduce the above copyright 24 * notice, this list of conditions and the following disclaimer in the 25 * documentation and/or other materials provided with the distribution. 26 * 3. The name of the author may not be used to endorse or promote 27 * products derived from this software without specific prior 28 * written permission. 29 * 30 * ALTERNATIVELY, this product may be distributed under the terms of 31 * the GNU Public License, in which case the provisions of the GPL are 32 * required INSTEAD OF the above restrictions. (This clause is 33 * necessary due to a potential bad interaction between the GPL and 34 * the restrictions contained in a BSD-style copyright.) 35 * 36 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED 37 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 38 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 39 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 40 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 41 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 42 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 43 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 44 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 45 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 46 * OF THE POSSIBILITY OF SUCH DAMAGE. 47 * 48 */ 49 50#include <sys/cdefs.h> 51__FBSDID("$FreeBSD: head/lib/libpam/modules/pam_krb5/pam_krb5.c 109069 2003-01-10 13:38:44Z nectar $"); 52 53#include <sys/types.h> 54#include <sys/stat.h> 55#include <errno.h> 56#include <limits.h> 57#include <pwd.h> 58#include <stdio.h> 59#include <stdlib.h> 60#include <string.h> 61#include <syslog.h> 62#include <unistd.h> 63 64#include <krb5.h> 65#include <com_err.h> 66 67#define PAM_SM_AUTH 68#define PAM_SM_ACCOUNT 69#define PAM_SM_PASSWORD 70 71#include <security/pam_appl.h> 72#include <security/pam_modules.h> 73#include <security/pam_mod_misc.h> 74 75#define COMPAT_HEIMDAL 76/* #define COMPAT_MIT */ 77 78static int verify_krb_v5_tgt(krb5_context, krb5_ccache, char *, int); 79static void cleanup_cache(pam_handle_t *, void *, int); 80static const char *compat_princ_component(krb5_context, krb5_principal, int); 81static void compat_free_data_contents(krb5_context, krb5_data *); 82 83#define USER_PROMPT "Username: " 84#define PASSWORD_PROMPT "Password:" 85#define NEW_PASSWORD_PROMPT "New Password:" 86 87enum { 88 PAM_OPT_AUTH_AS_SELF = PAM_OPT_STD_MAX, 89 PAM_OPT_CCACHE, 90 PAM_OPT_FORWARDABLE, 91 PAM_OPT_NO_CCACHE, 92 PAM_OPT_REUSE_CCACHE 93}; 94 95static struct opttab other_options[] = { 96 { "auth_as_self", PAM_OPT_AUTH_AS_SELF }, 97 { "ccache", PAM_OPT_CCACHE }, 98 { "forwardable", PAM_OPT_FORWARDABLE }, 99 { "no_ccache", PAM_OPT_NO_CCACHE }, 100 { "reuse_ccache", PAM_OPT_REUSE_CCACHE }, 101 { NULL, 0 } 102}; 103 104/* 105 * authentication management 106 */ 107PAM_EXTERN int 108pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 109 int argc, const char *argv[]) 110{ 111 krb5_error_code krbret; 112 krb5_context pam_context; 113 krb5_creds creds; 114 krb5_principal princ; 115 krb5_ccache ccache; 116 krb5_get_init_creds_opt opts; 117 struct options options; 118 struct passwd *pwd; 119 int retval; 120 const char *sourceuser, *user, *pass, *service; 121 char *principal, *princ_name, *ccache_name, luser[32], *srvdup; 122 123 pam_std_option(&options, other_options, argc, argv); 124 125 PAM_LOG("Options processed"); 126 127 retval = pam_get_user(pamh, &user, USER_PROMPT); 128 if (retval != PAM_SUCCESS) 129 return (retval); 130 131 PAM_LOG("Got user: %s", user); 132 133 retval = pam_get_item(pamh, PAM_RUSER, (const void **)&sourceuser); 134 if (retval != PAM_SUCCESS) 135 return (retval); 136 137 PAM_LOG("Got ruser: %s", sourceuser); 138 139 service = NULL; 140 pam_get_item(pamh, PAM_SERVICE, (const void **)&service); 141 if (service == NULL) 142 service = "unknown"; 143 144 PAM_LOG("Got service: %s", service); 145 146 krbret = krb5_init_context(&pam_context); 147 if (krbret != 0) { 148 PAM_VERBOSE_ERROR("Kerberos 5 error"); 149 return (PAM_SERVICE_ERR); 150 } 151 152 PAM_LOG("Context initialised"); 153 154 krb5_get_init_creds_opt_init(&opts); 155 156 if (pam_test_option(&options, PAM_OPT_FORWARDABLE, NULL)) 157 krb5_get_init_creds_opt_set_forwardable(&opts, 1); 158 159 PAM_LOG("Credentials initialised"); 160 161 krbret = krb5_cc_register(pam_context, &krb5_mcc_ops, FALSE); 162 if (krbret != 0 && krbret != KRB5_CC_TYPE_EXISTS) { 163 PAM_VERBOSE_ERROR("Kerberos 5 error"); 164 retval = PAM_SERVICE_ERR; 165 goto cleanup3; 166 } 167 168 PAM_LOG("Done krb5_cc_register()"); 169 170 /* Get principal name */ 171 if (pam_test_option(&options, PAM_OPT_AUTH_AS_SELF, NULL)) 172 asprintf(&principal, "%s/%s", sourceuser, user); 173 else 174 principal = strdup(user); 175 176 PAM_LOG("Created principal: %s", principal); 177 178 krbret = krb5_parse_name(pam_context, principal, &princ); 179 free(principal); 180 if (krbret != 0) { 181 PAM_LOG("Error krb5_parse_name(): %s", 182 krb5_get_err_text(pam_context, krbret)); 183 PAM_VERBOSE_ERROR("Kerberos 5 error"); 184 retval = PAM_SERVICE_ERR; 185 goto cleanup3; 186 } 187 188 PAM_LOG("Done krb5_parse_name()"); 189 190 /* Now convert the principal name into something human readable */ 191 princ_name = NULL; 192 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 193 if (krbret != 0) { 194 PAM_LOG("Error krb5_unparse_name(): %s", 195 krb5_get_err_text(pam_context, krbret)); 196 PAM_VERBOSE_ERROR("Kerberos 5 error"); 197 retval = PAM_SERVICE_ERR; 198 goto cleanup2; 199 } 200 201 PAM_LOG("Got principal: %s", princ_name); 202 203 /* Get password */ 204 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT); 205 if (retval != PAM_SUCCESS) 206 goto cleanup2; 207 208 PAM_LOG("Got password"); 209 210 /* Verify the local user exists (AFTER getting the password) */ 211 if (strchr(user, '@')) { 212 /* get a local account name for this principal */ 213 krbret = krb5_aname_to_localname(pam_context, princ, 214 sizeof(luser), luser); 215 if (krbret != 0) { 216 PAM_VERBOSE_ERROR("Kerberos 5 error"); 217 PAM_LOG("Error krb5_aname_to_localname(): %s", 218 krb5_get_err_text(pam_context, krbret)); 219 retval = PAM_USER_UNKNOWN; 220 goto cleanup2; 221 } 222 223 retval = pam_set_item(pamh, PAM_USER, luser); 224 if (retval != PAM_SUCCESS) 225 goto cleanup2; 226 227 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 228 if (retval != PAM_SUCCESS) 229 goto cleanup2; 230 231 PAM_LOG("PAM_USER Redone"); 232 } 233 234 pwd = getpwnam(user); 235 if (pwd == NULL) { 236 retval = PAM_USER_UNKNOWN; 237 goto cleanup2; 238 } 239 240 PAM_LOG("Done getpwnam()"); 241 242 /* Get a TGT */ 243 memset(&creds, 0, sizeof(krb5_creds)); 244 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 245 pass, NULL, pamh, 0, NULL, &opts); 246 if (krbret != 0) { 247 PAM_VERBOSE_ERROR("Kerberos 5 error"); 248 PAM_LOG("Error krb5_get_init_creds_password(): %s", 249 krb5_get_err_text(pam_context, krbret)); 250 retval = PAM_AUTH_ERR; 251 goto cleanup2; 252 } 253 254 PAM_LOG("Got TGT"); 255 256 /* Generate a temporary cache */ 257 krbret = krb5_cc_gen_new(pam_context, &krb5_mcc_ops, &ccache); 258 if (krbret != 0) { 259 PAM_VERBOSE_ERROR("Kerberos 5 error"); 260 PAM_LOG("Error krb5_cc_gen_new(): %s", 261 krb5_get_err_text(pam_context, krbret)); 262 retval = PAM_SERVICE_ERR; 263 goto cleanup; 264 } 265 krbret = krb5_cc_initialize(pam_context, ccache, princ); 266 if (krbret != 0) { 267 PAM_VERBOSE_ERROR("Kerberos 5 error"); 268 PAM_LOG("Error krb5_cc_initialize(): %s", 269 krb5_get_err_text(pam_context, krbret)); 270 retval = PAM_SERVICE_ERR; 271 goto cleanup; 272 } 273 krbret = krb5_cc_store_cred(pam_context, ccache, &creds); 274 if (krbret != 0) { 275 PAM_VERBOSE_ERROR("Kerberos 5 error"); 276 PAM_LOG("Error krb5_cc_store_cred(): %s", 277 krb5_get_err_text(pam_context, krbret)); 278 krb5_cc_destroy(pam_context, ccache); 279 retval = PAM_SERVICE_ERR; 280 goto cleanup; 281 } 282 283 PAM_LOG("Credentials stashed"); 284 285 /* Verify them */ 286 if ((srvdup = strdup(service)) == NULL) { 287 retval = PAM_BUF_ERR; 288 goto cleanup; 289 } 290 krbret = verify_krb_v5_tgt(pam_context, ccache, srvdup, 291 pam_test_option(&options, PAM_OPT_FORWARDABLE, NULL)); 292 free(srvdup); 293 if (krbret == -1) { 294 PAM_VERBOSE_ERROR("Kerberos 5 error"); 295 krb5_cc_destroy(pam_context, ccache); 296 retval = PAM_AUTH_ERR; 297 goto cleanup; 298 } 299 300 PAM_LOG("Credentials stash verified"); 301 302 retval = pam_get_data(pamh, "ccache", (const void **)&ccache_name); 303 if (retval == PAM_SUCCESS) { 304 krb5_cc_destroy(pam_context, ccache); 305 PAM_VERBOSE_ERROR("Kerberos 5 error"); 306 retval = PAM_AUTH_ERR; 307 goto cleanup; 308 } 309 310 PAM_LOG("Credentials stash not pre-existing"); 311 312 asprintf(&ccache_name, "%s:%s", krb5_cc_get_type(pam_context, 313 ccache), krb5_cc_get_name(pam_context, ccache)); 314 if (ccache_name == NULL) { 315 PAM_VERBOSE_ERROR("Kerberos 5 error"); 316 retval = PAM_BUF_ERR; 317 goto cleanup; 318 } 319 retval = pam_set_data(pamh, "ccache", ccache_name, cleanup_cache); 320 if (retval != 0) { 321 krb5_cc_destroy(pam_context, ccache); 322 PAM_VERBOSE_ERROR("Kerberos 5 error"); 323 retval = PAM_SERVICE_ERR; 324 goto cleanup; 325 } 326 327 PAM_LOG("Credentials stash saved"); 328 329cleanup: 330 krb5_free_cred_contents(pam_context, &creds); 331 PAM_LOG("Done cleanup"); 332cleanup2: 333 krb5_free_principal(pam_context, princ); 334 PAM_LOG("Done cleanup2"); 335cleanup3: 336 if (princ_name) 337 free(princ_name); 338 339 krb5_free_context(pam_context); 340 341 PAM_LOG("Done cleanup3"); 342 343 if (retval != PAM_SUCCESS) 344 PAM_VERBOSE_ERROR("Kerberos 5 refuses you"); 345 346 return (retval); 347} 348 349PAM_EXTERN int 350pam_sm_setcred(pam_handle_t *pamh, int flags, 351 int argc, const char *argv[]) 352{ 353 354 krb5_error_code krbret; 355 krb5_context pam_context; 356 krb5_principal princ; 357 krb5_creds creds; 358 krb5_ccache ccache_temp, ccache_perm; 359 krb5_cc_cursor cursor; 360 struct options options; 361 struct passwd *pwd = NULL; 362 int retval; 363 char *user; 364 char *cache_name, *cache_env_name, *p, *q; 365 366 uid_t euid; 367 gid_t egid; 368 369 pam_std_option(&options, other_options, argc, argv); 370 371 PAM_LOG("Options processed"); 372 373 if (flags & PAM_DELETE_CRED) 374 return (PAM_SUCCESS); 375 376 if (flags & PAM_REFRESH_CRED) 377 return (PAM_SUCCESS); 378 379 if (flags & PAM_REINITIALIZE_CRED) 380 return (PAM_SUCCESS); 381 382 if (!(flags & PAM_ESTABLISH_CRED)) 383 return (PAM_SERVICE_ERR); 384 385 PAM_LOG("Establishing credentials"); 386 387 /* Get username */ 388 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 389 if (retval != PAM_SUCCESS) 390 return (retval); 391 392 PAM_LOG("Got user: %s", user); 393 394 krbret = krb5_init_context(&pam_context); 395 if (krbret != 0) { 396 PAM_LOG("Error krb5_init_context() failed"); 397 return (PAM_SERVICE_ERR); 398 } 399 400 PAM_LOG("Context initialised"); 401 402 euid = geteuid(); /* Usually 0 */ 403 egid = getegid(); 404 405 PAM_LOG("Got euid, egid: %d %d", euid, egid); 406 407 /* Retrieve the temporary cache */ 408 retval = pam_get_data(pamh, "ccache", (const void **)&cache_name); 409 if (retval != PAM_SUCCESS) 410 goto cleanup3; 411 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_temp); 412 if (krbret != 0) { 413 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", cache_name, 414 krb5_get_err_text(pam_context, krbret)); 415 goto cleanup3; 416 } 417 418 /* Get the uid. This should exist. */ 419 pwd = getpwnam(user); 420 if (pwd == NULL) { 421 retval = PAM_USER_UNKNOWN; 422 goto cleanup3; 423 } 424 425 PAM_LOG("Done getpwnam()"); 426 427 /* Avoid following a symlink as root */ 428 if (setegid(pwd->pw_gid)) { 429 retval = PAM_SERVICE_ERR; 430 goto cleanup3; 431 } 432 if (seteuid(pwd->pw_uid)) { 433 retval = PAM_SERVICE_ERR; 434 goto cleanup3; 435 } 436 437 PAM_LOG("Done setegid() & seteuid()"); 438 439 /* Get the cache name */ 440 cache_name = NULL; 441 pam_test_option(&options, PAM_OPT_CCACHE, &cache_name); 442 if (cache_name == NULL) 443 asprintf(&cache_name, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 444 445 p = calloc(PATH_MAX + 16, sizeof(char)); 446 q = cache_name; 447 448 if (p == NULL) { 449 PAM_LOG("Error malloc(): failure"); 450 retval = PAM_BUF_ERR; 451 goto cleanup3; 452 } 453 cache_name = p; 454 455 /* convert %u and %p */ 456 while (*q) { 457 if (*q == '%') { 458 q++; 459 if (*q == 'u') { 460 sprintf(p, "%d", pwd->pw_uid); 461 p += strlen(p); 462 } 463 else if (*q == 'p') { 464 sprintf(p, "%d", getpid()); 465 p += strlen(p); 466 } 467 else { 468 /* Not a special token */ 469 *p++ = '%'; 470 q--; 471 } 472 q++; 473 } 474 else { 475 *p++ = *q++; 476 } 477 } 478 479 PAM_LOG("Got cache_name: %s", cache_name); 480 481 /* Initialize the new ccache */ 482 krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ); 483 if (krbret != 0) { 484 PAM_LOG("Error krb5_cc_get_principal(): %s", 485 krb5_get_err_text(pam_context, krbret)); 486 retval = PAM_SERVICE_ERR; 487 goto cleanup3; 488 } 489 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm); 490 if (krbret != 0) { 491 PAM_LOG("Error krb5_cc_resolve(): %s", 492 krb5_get_err_text(pam_context, krbret)); 493 retval = PAM_SERVICE_ERR; 494 goto cleanup2; 495 } 496 krbret = krb5_cc_initialize(pam_context, ccache_perm, princ); 497 if (krbret != 0) { 498 PAM_LOG("Error krb5_cc_initialize(): %s", 499 krb5_get_err_text(pam_context, krbret)); 500 retval = PAM_SERVICE_ERR; 501 goto cleanup2; 502 } 503 504 PAM_LOG("Cache initialised"); 505 506 /* Prepare for iteration over creds */ 507 krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor); 508 if (krbret != 0) { 509 PAM_LOG("Error krb5_cc_start_seq_get(): %s", 510 krb5_get_err_text(pam_context, krbret)); 511 krb5_cc_destroy(pam_context, ccache_perm); 512 retval = PAM_SERVICE_ERR; 513 goto cleanup2; 514 } 515 516 PAM_LOG("Prepared for iteration"); 517 518 /* Copy the creds (should be two of them) */ 519 while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp, 520 &cursor, &creds) == 0)) { 521 krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds); 522 if (krbret != 0) { 523 PAM_LOG("Error krb5_cc_store_cred(): %s", 524 krb5_get_err_text(pam_context, krbret)); 525 krb5_cc_destroy(pam_context, ccache_perm); 526 krb5_free_cred_contents(pam_context, &creds); 527 retval = PAM_SERVICE_ERR; 528 goto cleanup2; 529 } 530 krb5_free_cred_contents(pam_context, &creds); 531 PAM_LOG("Iteration"); 532 } 533 krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor); 534 535 PAM_LOG("Done iterating"); 536 537 if (strstr(cache_name, "FILE:") == cache_name) { 538 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 539 PAM_LOG("Error chown(): %s", strerror(errno)); 540 krb5_cc_destroy(pam_context, ccache_perm); 541 retval = PAM_SERVICE_ERR; 542 goto cleanup2; 543 } 544 PAM_LOG("Done chown()"); 545 546 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 547 PAM_LOG("Error chmod(): %s", strerror(errno)); 548 krb5_cc_destroy(pam_context, ccache_perm); 549 retval = PAM_SERVICE_ERR; 550 goto cleanup2; 551 } 552 PAM_LOG("Done chmod()"); 553 } 554 555 krb5_cc_close(pam_context, ccache_perm); 556 557 PAM_LOG("Cache closed"); 558 559 cache_env_name = malloc(strlen(cache_name) + 12); 560 if (!cache_env_name) { 561 PAM_LOG("Error malloc(): failure"); 562 krb5_cc_destroy(pam_context, ccache_perm); 563 retval = PAM_BUF_ERR; 564 goto cleanup2; 565 } 566 567 sprintf(cache_env_name, "KRB5CCNAME=%s", cache_name); 568 if ((retval = pam_putenv(pamh, cache_env_name)) != 0) { 569 PAM_LOG("Error pam_putenv(): %s", pam_strerror(pamh, retval)); 570 krb5_cc_destroy(pam_context, ccache_perm); 571 retval = PAM_SERVICE_ERR; 572 goto cleanup2; 573 } 574 575 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 576 577cleanup2: 578 krb5_free_principal(pam_context, princ); 579 PAM_LOG("Done cleanup2"); 580cleanup3: 581 krb5_free_context(pam_context); 582 PAM_LOG("Done cleanup3"); 583 584 seteuid(euid); 585 setegid(egid); 586 587 PAM_LOG("Done seteuid() & setegid()"); 588 589 return (retval); 590} 591 592/* 593 * account management 594 */ 595PAM_EXTERN int 596pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 597 int argc, const char *argv[]) 598{ 599 krb5_error_code krbret; 600 krb5_context pam_context; 601 krb5_ccache ccache; 602 krb5_principal princ; 603 struct options options; 604 int retval; 605 const char *user, *ccache_name; 606 607 pam_std_option(&options, other_options, argc, argv); 608 609 PAM_LOG("Options processed"); 610 611 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 612 if (retval != PAM_SUCCESS) 613 return (retval); 614 615 PAM_LOG("Got user: %s", user); 616 617 krbret = krb5_init_context(&pam_context); 618 if (krbret != 0) { 619 PAM_LOG("Error krb5_init_context() failed"); 620 return (PAM_PERM_DENIED); 621 } 622 623 PAM_LOG("Context initialised"); 624 625 retval = pam_get_data(pamh, "ccache", (const void **)&ccache_name); 626 if (retval != PAM_SUCCESS) 627 return (PAM_SUCCESS); 628 krbret = krb5_cc_resolve(pam_context, ccache_name, &ccache); 629 if (krbret != 0) { 630 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", ccache_name, 631 krb5_get_err_text(pam_context, krbret)); 632 krb5_free_context(pam_context); 633 return (PAM_PERM_DENIED); 634 } 635 636 PAM_LOG("Got ccache %s", ccache_name); 637 638 639 krbret = krb5_cc_get_principal(pam_context, ccache, &princ); 640 if (krbret != 0) { 641 PAM_LOG("Error krb5_cc_get_principal(): %s", 642 krb5_get_err_text(pam_context, krbret)); 643 retval = PAM_PERM_DENIED;; 644 goto cleanup; 645 } 646 647 PAM_LOG("Got principal"); 648 649 if (krb5_kuserok(pam_context, princ, user)) 650 retval = PAM_SUCCESS; 651 else 652 retval = PAM_PERM_DENIED; 653 krb5_free_principal(pam_context, princ); 654 655 PAM_LOG("Done kuserok()"); 656 657cleanup: 658 krb5_free_context(pam_context); 659 PAM_LOG("Done cleanup"); 660 661 return (retval); 662 663} 664 665/* 666 * password management 667 */ 668PAM_EXTERN int 669pam_sm_chauthtok(pam_handle_t *pamh, int flags, 670 int argc, const char *argv[]) 671{ 672 krb5_error_code krbret; 673 krb5_context pam_context; 674 krb5_creds creds; 675 krb5_principal princ; 676 krb5_get_init_creds_opt opts; 677 krb5_data result_code_string, result_string; 678 struct options options; 679 int result_code, retval; 680 const char *user, *pass; 681 char *princ_name, *passdup; 682 683 pam_std_option(&options, other_options, argc, argv); 684 685 PAM_LOG("Options processed"); 686 687 if (!(flags & PAM_UPDATE_AUTHTOK)) 688 return (PAM_AUTHTOK_ERR); 689 690 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 691 if (retval != PAM_SUCCESS) 692 return (retval); 693 694 PAM_LOG("Got user: %s", user); 695 696 krbret = krb5_init_context(&pam_context); 697 if (krbret != 0) { 698 PAM_LOG("Error krb5_init_context() failed"); 699 return (PAM_SERVICE_ERR); 700 } 701 702 PAM_LOG("Context initialised"); 703 704 krb5_get_init_creds_opt_init(&opts); 705 706 PAM_LOG("Credentials options initialised"); 707 708 /* Get principal name */ 709 krbret = krb5_parse_name(pam_context, user, &princ); 710 if (krbret != 0) { 711 PAM_LOG("Error krb5_parse_name(): %s", 712 krb5_get_err_text(pam_context, krbret)); 713 retval = PAM_USER_UNKNOWN; 714 goto cleanup3; 715 } 716 717 /* Now convert the principal name into something human readable */ 718 princ_name = NULL; 719 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 720 if (krbret != 0) { 721 PAM_LOG("Error krb5_unparse_name(): %s", 722 krb5_get_err_text(pam_context, krbret)); 723 retval = PAM_SERVICE_ERR; 724 goto cleanup2; 725 } 726 727 PAM_LOG("Got principal: %s", princ_name); 728 729 /* Get password */ 730 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT); 731 if (retval != PAM_SUCCESS) 732 goto cleanup2; 733 734 PAM_LOG("Got password"); 735 736 memset(&creds, 0, sizeof(krb5_creds)); 737 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 738 pass, NULL, pamh, 0, "kadmin/changepw", &opts); 739 if (krbret != 0) { 740 PAM_LOG("Error krb5_get_init_creds_password()", 741 krb5_get_err_text(pam_context, krbret)); 742 retval = PAM_AUTH_ERR; 743 goto cleanup2; 744 } 745 746 PAM_LOG("Credentials established"); 747 748 /* Now get the new password */ 749 for (;;) { 750 retval = pam_get_authtok(pamh, 751 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 752 if (retval != PAM_TRY_AGAIN) 753 break; 754 pam_error(pamh, "Mismatch; try again, EOF to quit."); 755 } 756 if (retval != PAM_SUCCESS) 757 goto cleanup; 758 759 PAM_LOG("Got new password"); 760 761 /* Change it */ 762 if ((passdup = strdup(pass)) == NULL) { 763 retval = PAM_BUF_ERR; 764 goto cleanup; 765 } 766 krbret = krb5_change_password(pam_context, &creds, passdup, 767 &result_code, &result_code_string, &result_string); 768 free(passdup); 769 if (krbret != 0) { 770 PAM_LOG("Error krb5_change_password(): %s", 771 krb5_get_err_text(pam_context, krbret)); 772 retval = PAM_AUTHTOK_ERR; 773 goto cleanup; 774 } 775 if (result_code) { 776 PAM_LOG("Error krb5_change_password(): (result_code)"); 777 retval = PAM_AUTHTOK_ERR; 778 goto cleanup; 779 } 780 781 PAM_LOG("Password changed"); 782 783 if (result_string.data) 784 free(result_string.data); 785 if (result_code_string.data) 786 free(result_code_string.data); 787 788cleanup: 789 krb5_free_cred_contents(pam_context, &creds); 790 PAM_LOG("Done cleanup"); 791cleanup2: 792 krb5_free_principal(pam_context, princ); 793 PAM_LOG("Done cleanup2"); 794cleanup3: 795 if (princ_name) 796 free(princ_name); 797 798 krb5_free_context(pam_context); 799 800 PAM_LOG("Done cleanup3"); 801 802 return (retval); 803} 804 805PAM_MODULE_ENTRY("pam_krb5"); 806 807/* 808 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 809 * Modified by Sam Hartman <hartmans@mit.edu> to support PAM services 810 * for Debian. 811 * 812 * Verify the Kerberos ticket-granting ticket just retrieved for the 813 * user. If the Kerberos server doesn't respond, assume the user is 814 * trying to fake us out (since we DID just get a TGT from what is 815 * supposedly our KDC). If the host/<host> service is unknown (i.e., 816 * the local keytab doesn't have it), and we cannot find another 817 * service we do have, let her in. 818 * 819 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 820 */ 821static int 822verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 823 char *pam_service, int debug) 824{ 825 krb5_error_code retval; 826 krb5_principal princ; 827 krb5_keyblock *keyblock; 828 krb5_data packet; 829 krb5_auth_context auth_context; 830 char phost[BUFSIZ]; 831 const char *services[3], **service; 832 833 packet.data = 0; 834 835 /* If possible we want to try and verify the ticket we have 836 * received against a keytab. We will try multiple service 837 * principals, including at least the host principal and the PAM 838 * service principal. The host principal is preferred because access 839 * to that key is generally sufficient to compromise root, while the 840 * service key for this PAM service may be less carefully guarded. 841 * It is important to check the keytab first before the KDC so we do 842 * not get spoofed by a fake KDC. 843 */ 844 services[0] = "host"; 845 services[1] = pam_service; 846 services[2] = NULL; 847 keyblock = 0; 848 retval = -1; 849 for (service = &services[0]; *service != NULL; service++) { 850 retval = krb5_sname_to_principal(context, NULL, *service, 851 KRB5_NT_SRV_HST, &princ); 852 if (retval != 0) { 853 if (debug) 854 syslog(LOG_DEBUG, 855 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 856 "krb5_sname_to_principal()", 857 krb5_get_err_text(context, retval)); 858 return -1; 859 } 860 861 /* Extract the name directly. */ 862 strncpy(phost, compat_princ_component(context, princ, 1), 863 BUFSIZ); 864 phost[BUFSIZ - 1] = '\0'; 865 866 /* 867 * Do we have service/<host> keys? 868 * (use default/configured keytab, kvno IGNORE_VNO to get the 869 * first match, and ignore enctype.) 870 */ 871 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 872 &keyblock); 873 if (retval != 0) 874 continue; 875 break; 876 } 877 if (retval != 0) { /* failed to find key */ 878 /* Keytab or service key does not exist */ 879 if (debug) 880 syslog(LOG_DEBUG, 881 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 882 "krb5_kt_read_service_key()", 883 krb5_get_err_text(context, retval)); 884 retval = 0; 885 goto cleanup; 886 } 887 if (keyblock) 888 krb5_free_keyblock(context, keyblock); 889 890 /* Talk to the kdc and construct the ticket. */ 891 auth_context = NULL; 892 retval = krb5_mk_req(context, &auth_context, 0, *service, phost, 893 NULL, ccache, &packet); 894 if (auth_context) { 895 krb5_auth_con_free(context, auth_context); 896 auth_context = NULL; /* setup for rd_req */ 897 } 898 if (retval) { 899 if (debug) 900 syslog(LOG_DEBUG, 901 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 902 "krb5_mk_req()", 903 krb5_get_err_text(context, retval)); 904 retval = -1; 905 goto cleanup; 906 } 907 908 /* Try to use the ticket. */ 909 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 910 NULL, NULL); 911 if (retval) { 912 if (debug) 913 syslog(LOG_DEBUG, 914 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 915 "krb5_rd_req()", 916 krb5_get_err_text(context, retval)); 917 retval = -1; 918 } 919 else 920 retval = 1; 921 922cleanup: 923 if (packet.data) 924 compat_free_data_contents(context, &packet); 925 krb5_free_principal(context, princ); 926 return retval; 927} 928 929/* Free the memory for cache_name. Called by pam_end() */ 930static void 931cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 932{ 933 krb5_context pam_context; 934 krb5_ccache ccache; 935 krb5_error_code krbret; 936 937 if (krb5_init_context(&pam_context)) 938 return; 939 940 krbret = krb5_cc_resolve(pam_context, data, &ccache); 941 if (krbret == 0) 942 krb5_cc_destroy(pam_context, ccache); 943 krb5_free_context(pam_context); 944 free(data); 945} 946 947#ifdef COMPAT_HEIMDAL 948#ifdef COMPAT_MIT 949#error This cannot be MIT and Heimdal compatible! 950#endif 951#endif 952 953#ifndef COMPAT_HEIMDAL 954#ifndef COMPAT_MIT 955#error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 956#endif 957#endif 958 959#ifdef COMPAT_HEIMDAL 960static const char * 961compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 962{ 963 return princ->name.name_string.val[n]; 964} 965 966static void 967compat_free_data_contents(krb5_context context __unused, krb5_data * data) 968{ 969 krb5_xfree(data->data); 970} 971#endif 972 973#ifdef COMPAT_MIT 974static const char * 975compat_princ_component(krb5_context context, krb5_principal princ, int n) 976{ 977 return krb5_princ_component(context, princ, n)->data; 978} 979 980static void 981compat_free_data_contents(krb5_context context, krb5_data * data) 982{ 983 krb5_free_data_contents(context, data); 984} 985#endif 986