pam_krb5.c revision 147810
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., 2002-2005. 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 147810 2005-07-07 14:16:38Z kensmith $"); 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#include <security/openpam.h> 75 76#define COMPAT_HEIMDAL 77/* #define COMPAT_MIT */ 78 79static int verify_krb_v5_tgt(krb5_context, krb5_ccache, char *, int); 80static void cleanup_cache(pam_handle_t *, void *, int); 81static const char *compat_princ_component(krb5_context, krb5_principal, int); 82static void compat_free_data_contents(krb5_context, krb5_data *); 83 84#define USER_PROMPT "Username: " 85#define PASSWORD_PROMPT "Password:" 86#define NEW_PASSWORD_PROMPT "New Password:" 87 88#define PAM_OPT_CCACHE "ccache" 89#define PAM_OPT_DEBUG "debug" 90#define PAM_OPT_FORWARDABLE "forwardable" 91#define PAM_OPT_NO_CCACHE "no_ccache" 92#define PAM_OPT_REUSE_CCACHE "reuse_ccache" 93 94/* 95 * authentication management 96 */ 97PAM_EXTERN int 98pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 99 int argc __unused, const char *argv[] __unused) 100{ 101 krb5_error_code krbret; 102 krb5_context pam_context; 103 krb5_creds creds; 104 krb5_principal princ; 105 krb5_ccache ccache; 106 krb5_get_init_creds_opt opts; 107 struct passwd *pwd; 108 int retval; 109 void *ccache_data; 110 const char *user, *pass; 111 const void *sourceuser, *service; 112 char *principal, *princ_name, *ccache_name, luser[32], *srvdup; 113 114 retval = pam_get_user(pamh, &user, USER_PROMPT); 115 if (retval != PAM_SUCCESS) 116 return (retval); 117 118 PAM_LOG("Got user: %s", user); 119 120 retval = pam_get_item(pamh, PAM_RUSER, &sourceuser); 121 if (retval != PAM_SUCCESS) 122 return (retval); 123 124 PAM_LOG("Got ruser: %s", (const char *)sourceuser); 125 126 service = NULL; 127 pam_get_item(pamh, PAM_SERVICE, &service); 128 if (service == NULL) 129 service = "unknown"; 130 131 PAM_LOG("Got service: %s", (const char *)service); 132 133 krbret = krb5_init_context(&pam_context); 134 if (krbret != 0) { 135 PAM_VERBOSE_ERROR("Kerberos 5 error"); 136 return (PAM_SERVICE_ERR); 137 } 138 139 PAM_LOG("Context initialised"); 140 141 krb5_get_init_creds_opt_init(&opts); 142 143 if (openpam_get_option(pamh, PAM_OPT_FORWARDABLE)) 144 krb5_get_init_creds_opt_set_forwardable(&opts, 1); 145 146 PAM_LOG("Credentials initialised"); 147 148 krbret = krb5_cc_register(pam_context, &krb5_mcc_ops, FALSE); 149 if (krbret != 0 && krbret != KRB5_CC_TYPE_EXISTS) { 150 PAM_VERBOSE_ERROR("Kerberos 5 error"); 151 retval = PAM_SERVICE_ERR; 152 goto cleanup3; 153 } 154 155 PAM_LOG("Done krb5_cc_register()"); 156 157 /* Get principal name */ 158 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) 159 asprintf(&principal, "%s/%s", (const char *)sourceuser, user); 160 else 161 principal = strdup(user); 162 163 PAM_LOG("Created principal: %s", principal); 164 165 krbret = krb5_parse_name(pam_context, principal, &princ); 166 free(principal); 167 if (krbret != 0) { 168 PAM_LOG("Error krb5_parse_name(): %s", 169 krb5_get_err_text(pam_context, krbret)); 170 PAM_VERBOSE_ERROR("Kerberos 5 error"); 171 retval = PAM_SERVICE_ERR; 172 goto cleanup3; 173 } 174 175 PAM_LOG("Done krb5_parse_name()"); 176 177 /* Now convert the principal name into something human readable */ 178 princ_name = NULL; 179 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 180 if (krbret != 0) { 181 PAM_LOG("Error krb5_unparse_name(): %s", 182 krb5_get_err_text(pam_context, krbret)); 183 PAM_VERBOSE_ERROR("Kerberos 5 error"); 184 retval = PAM_SERVICE_ERR; 185 goto cleanup2; 186 } 187 188 PAM_LOG("Got principal: %s", princ_name); 189 190 /* Get password */ 191 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT); 192 if (retval != PAM_SUCCESS) 193 goto cleanup2; 194 195 PAM_LOG("Got password"); 196 197 /* Verify the local user exists (AFTER getting the password) */ 198 if (strchr(user, '@')) { 199 /* get a local account name for this principal */ 200 krbret = krb5_aname_to_localname(pam_context, princ, 201 sizeof(luser), luser); 202 if (krbret != 0) { 203 PAM_VERBOSE_ERROR("Kerberos 5 error"); 204 PAM_LOG("Error krb5_aname_to_localname(): %s", 205 krb5_get_err_text(pam_context, krbret)); 206 retval = PAM_USER_UNKNOWN; 207 goto cleanup2; 208 } 209 210 retval = pam_set_item(pamh, PAM_USER, luser); 211 if (retval != PAM_SUCCESS) 212 goto cleanup2; 213 214 PAM_LOG("PAM_USER Redone"); 215 } 216 217 pwd = getpwnam(user); 218 if (pwd == NULL) { 219 retval = PAM_USER_UNKNOWN; 220 goto cleanup2; 221 } 222 223 PAM_LOG("Done getpwnam()"); 224 225 /* Get a TGT */ 226 memset(&creds, 0, sizeof(krb5_creds)); 227 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 228 pass, NULL, pamh, 0, NULL, &opts); 229 if (krbret != 0) { 230 PAM_VERBOSE_ERROR("Kerberos 5 error"); 231 PAM_LOG("Error krb5_get_init_creds_password(): %s", 232 krb5_get_err_text(pam_context, krbret)); 233 retval = PAM_AUTH_ERR; 234 goto cleanup2; 235 } 236 237 PAM_LOG("Got TGT"); 238 239 /* Generate a temporary cache */ 240 krbret = krb5_cc_gen_new(pam_context, &krb5_mcc_ops, &ccache); 241 if (krbret != 0) { 242 PAM_VERBOSE_ERROR("Kerberos 5 error"); 243 PAM_LOG("Error krb5_cc_gen_new(): %s", 244 krb5_get_err_text(pam_context, krbret)); 245 retval = PAM_SERVICE_ERR; 246 goto cleanup; 247 } 248 krbret = krb5_cc_initialize(pam_context, ccache, princ); 249 if (krbret != 0) { 250 PAM_VERBOSE_ERROR("Kerberos 5 error"); 251 PAM_LOG("Error krb5_cc_initialize(): %s", 252 krb5_get_err_text(pam_context, krbret)); 253 retval = PAM_SERVICE_ERR; 254 goto cleanup; 255 } 256 krbret = krb5_cc_store_cred(pam_context, ccache, &creds); 257 if (krbret != 0) { 258 PAM_VERBOSE_ERROR("Kerberos 5 error"); 259 PAM_LOG("Error krb5_cc_store_cred(): %s", 260 krb5_get_err_text(pam_context, krbret)); 261 krb5_cc_destroy(pam_context, ccache); 262 retval = PAM_SERVICE_ERR; 263 goto cleanup; 264 } 265 266 PAM_LOG("Credentials stashed"); 267 268 /* Verify them */ 269 if ((srvdup = strdup(service)) == NULL) { 270 retval = PAM_BUF_ERR; 271 goto cleanup; 272 } 273 krbret = verify_krb_v5_tgt(pam_context, ccache, srvdup, 274 openpam_get_option(pamh, PAM_OPT_DEBUG) ? 1 : 0); 275 free(srvdup); 276 if (krbret == -1) { 277 PAM_VERBOSE_ERROR("Kerberos 5 error"); 278 krb5_cc_destroy(pam_context, ccache); 279 retval = PAM_AUTH_ERR; 280 goto cleanup; 281 } 282 283 PAM_LOG("Credentials stash verified"); 284 285 retval = pam_get_data(pamh, "ccache", &ccache_data); 286 if (retval == PAM_SUCCESS) { 287 krb5_cc_destroy(pam_context, ccache); 288 PAM_VERBOSE_ERROR("Kerberos 5 error"); 289 retval = PAM_AUTH_ERR; 290 goto cleanup; 291 } 292 293 PAM_LOG("Credentials stash not pre-existing"); 294 295 asprintf(&ccache_name, "%s:%s", krb5_cc_get_type(pam_context, 296 ccache), krb5_cc_get_name(pam_context, ccache)); 297 if (ccache_name == NULL) { 298 PAM_VERBOSE_ERROR("Kerberos 5 error"); 299 retval = PAM_BUF_ERR; 300 goto cleanup; 301 } 302 retval = pam_set_data(pamh, "ccache", ccache_name, cleanup_cache); 303 if (retval != 0) { 304 krb5_cc_destroy(pam_context, ccache); 305 PAM_VERBOSE_ERROR("Kerberos 5 error"); 306 retval = PAM_SERVICE_ERR; 307 goto cleanup; 308 } 309 310 PAM_LOG("Credentials stash saved"); 311 312cleanup: 313 krb5_free_cred_contents(pam_context, &creds); 314 PAM_LOG("Done cleanup"); 315cleanup2: 316 krb5_free_principal(pam_context, princ); 317 PAM_LOG("Done cleanup2"); 318cleanup3: 319 if (princ_name) 320 free(princ_name); 321 322 krb5_free_context(pam_context); 323 324 PAM_LOG("Done cleanup3"); 325 326 if (retval != PAM_SUCCESS) 327 PAM_VERBOSE_ERROR("Kerberos 5 refuses you"); 328 329 return (retval); 330} 331 332PAM_EXTERN int 333pam_sm_setcred(pam_handle_t *pamh, int flags, 334 int argc __unused, const char *argv[] __unused) 335{ 336#ifdef _FREEFALL_CONFIG 337 return (PAM_SUCCESS); 338#else 339 340 krb5_error_code krbret; 341 krb5_context pam_context; 342 krb5_principal princ; 343 krb5_creds creds; 344 krb5_ccache ccache_temp, ccache_perm; 345 krb5_cc_cursor cursor; 346 struct passwd *pwd = NULL; 347 int retval; 348 const char *cache_name, *q; 349 const void *user; 350 void *cache_data; 351 char *cache_name_buf = NULL, *p; 352 353 uid_t euid; 354 gid_t egid; 355 356 if (flags & PAM_DELETE_CRED) 357 return (PAM_SUCCESS); 358 359 if (flags & PAM_REFRESH_CRED) 360 return (PAM_SUCCESS); 361 362 if (flags & PAM_REINITIALIZE_CRED) 363 return (PAM_SUCCESS); 364 365 if (!(flags & PAM_ESTABLISH_CRED)) 366 return (PAM_SERVICE_ERR); 367 368 /* If a persistent cache isn't desired, stop now. */ 369 if (openpam_get_option(pamh, PAM_OPT_NO_CCACHE)) 370 return (PAM_SUCCESS); 371 372 PAM_LOG("Establishing credentials"); 373 374 /* Get username */ 375 retval = pam_get_item(pamh, PAM_USER, &user); 376 if (retval != PAM_SUCCESS) 377 return (retval); 378 379 PAM_LOG("Got user: %s", (const char *)user); 380 381 krbret = krb5_init_context(&pam_context); 382 if (krbret != 0) { 383 PAM_LOG("Error krb5_init_context() failed"); 384 return (PAM_SERVICE_ERR); 385 } 386 387 PAM_LOG("Context initialised"); 388 389 euid = geteuid(); /* Usually 0 */ 390 egid = getegid(); 391 392 PAM_LOG("Got euid, egid: %d %d", euid, egid); 393 394 /* Retrieve the temporary cache */ 395 retval = pam_get_data(pamh, "ccache", &cache_data); 396 if (retval != PAM_SUCCESS) { 397 retval = PAM_CRED_UNAVAIL; 398 goto cleanup3; 399 } 400 krbret = krb5_cc_resolve(pam_context, cache_data, &ccache_temp); 401 if (krbret != 0) { 402 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)cache_data, 403 krb5_get_err_text(pam_context, krbret)); 404 retval = PAM_SERVICE_ERR; 405 goto cleanup3; 406 } 407 408 /* Get the uid. This should exist. */ 409 pwd = getpwnam(user); 410 if (pwd == NULL) { 411 retval = PAM_USER_UNKNOWN; 412 goto cleanup3; 413 } 414 415 PAM_LOG("Done getpwnam()"); 416 417 /* Avoid following a symlink as root */ 418 if (setegid(pwd->pw_gid)) { 419 retval = PAM_SERVICE_ERR; 420 goto cleanup3; 421 } 422 if (seteuid(pwd->pw_uid)) { 423 retval = PAM_SERVICE_ERR; 424 goto cleanup3; 425 } 426 427 PAM_LOG("Done setegid() & seteuid()"); 428 429 /* Get the cache name */ 430 cache_name = openpam_get_option(pamh, PAM_OPT_CCACHE); 431 if (cache_name == NULL) { 432 asprintf(&cache_name_buf, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 433 cache_name = cache_name_buf; 434 } 435 436 p = calloc(PATH_MAX + 16, sizeof(char)); 437 q = cache_name; 438 439 if (p == NULL) { 440 PAM_LOG("Error malloc(): failure"); 441 retval = PAM_BUF_ERR; 442 goto cleanup3; 443 } 444 cache_name = p; 445 446 /* convert %u and %p */ 447 while (*q) { 448 if (*q == '%') { 449 q++; 450 if (*q == 'u') { 451 sprintf(p, "%d", pwd->pw_uid); 452 p += strlen(p); 453 } 454 else if (*q == 'p') { 455 sprintf(p, "%d", getpid()); 456 p += strlen(p); 457 } 458 else { 459 /* Not a special token */ 460 *p++ = '%'; 461 q--; 462 } 463 q++; 464 } 465 else { 466 *p++ = *q++; 467 } 468 } 469 470 PAM_LOG("Got cache_name: %s", cache_name); 471 472 /* Initialize the new ccache */ 473 krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ); 474 if (krbret != 0) { 475 PAM_LOG("Error krb5_cc_get_principal(): %s", 476 krb5_get_err_text(pam_context, krbret)); 477 retval = PAM_SERVICE_ERR; 478 goto cleanup3; 479 } 480 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm); 481 if (krbret != 0) { 482 PAM_LOG("Error krb5_cc_resolve(): %s", 483 krb5_get_err_text(pam_context, krbret)); 484 retval = PAM_SERVICE_ERR; 485 goto cleanup2; 486 } 487 krbret = krb5_cc_initialize(pam_context, ccache_perm, princ); 488 if (krbret != 0) { 489 PAM_LOG("Error krb5_cc_initialize(): %s", 490 krb5_get_err_text(pam_context, krbret)); 491 retval = PAM_SERVICE_ERR; 492 goto cleanup2; 493 } 494 495 PAM_LOG("Cache initialised"); 496 497 /* Prepare for iteration over creds */ 498 krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor); 499 if (krbret != 0) { 500 PAM_LOG("Error krb5_cc_start_seq_get(): %s", 501 krb5_get_err_text(pam_context, krbret)); 502 krb5_cc_destroy(pam_context, ccache_perm); 503 retval = PAM_SERVICE_ERR; 504 goto cleanup2; 505 } 506 507 PAM_LOG("Prepared for iteration"); 508 509 /* Copy the creds (should be two of them) */ 510 while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp, 511 &cursor, &creds) == 0)) { 512 krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds); 513 if (krbret != 0) { 514 PAM_LOG("Error krb5_cc_store_cred(): %s", 515 krb5_get_err_text(pam_context, krbret)); 516 krb5_cc_destroy(pam_context, ccache_perm); 517 krb5_free_cred_contents(pam_context, &creds); 518 retval = PAM_SERVICE_ERR; 519 goto cleanup2; 520 } 521 krb5_free_cred_contents(pam_context, &creds); 522 PAM_LOG("Iteration"); 523 } 524 krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor); 525 526 PAM_LOG("Done iterating"); 527 528 if (strstr(cache_name, "FILE:") == cache_name) { 529 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 530 PAM_LOG("Error chown(): %s", strerror(errno)); 531 krb5_cc_destroy(pam_context, ccache_perm); 532 retval = PAM_SERVICE_ERR; 533 goto cleanup2; 534 } 535 PAM_LOG("Done chown()"); 536 537 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 538 PAM_LOG("Error chmod(): %s", strerror(errno)); 539 krb5_cc_destroy(pam_context, ccache_perm); 540 retval = PAM_SERVICE_ERR; 541 goto cleanup2; 542 } 543 PAM_LOG("Done chmod()"); 544 } 545 546 krb5_cc_close(pam_context, ccache_perm); 547 548 PAM_LOG("Cache closed"); 549 550 retval = pam_setenv(pamh, "KRB5CCNAME", cache_name, 1); 551 if (retval != PAM_SUCCESS) { 552 PAM_LOG("Error pam_setenv(): %s", pam_strerror(pamh, retval)); 553 krb5_cc_destroy(pam_context, ccache_perm); 554 retval = PAM_SERVICE_ERR; 555 goto cleanup2; 556 } 557 558 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 559 560cleanup2: 561 krb5_free_principal(pam_context, princ); 562 PAM_LOG("Done cleanup2"); 563cleanup3: 564 krb5_free_context(pam_context); 565 PAM_LOG("Done cleanup3"); 566 567 seteuid(euid); 568 setegid(egid); 569 570 PAM_LOG("Done seteuid() & setegid()"); 571 572 if (cache_name_buf != NULL) 573 free(cache_name_buf); 574 575 return (retval); 576#endif 577} 578 579/* 580 * account management 581 */ 582PAM_EXTERN int 583pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 584 int argc __unused, const char *argv[] __unused) 585{ 586 krb5_error_code krbret; 587 krb5_context pam_context; 588 krb5_ccache ccache; 589 krb5_principal princ; 590 int retval; 591 const void *user; 592 void *ccache_name; 593 594 retval = pam_get_item(pamh, PAM_USER, &user); 595 if (retval != PAM_SUCCESS) 596 return (retval); 597 598 PAM_LOG("Got user: %s", (const char *)user); 599 600 retval = pam_get_data(pamh, "ccache", &ccache_name); 601 if (retval != PAM_SUCCESS) 602 return (PAM_SUCCESS); 603 604 PAM_LOG("Got credentials"); 605 606 krbret = krb5_init_context(&pam_context); 607 if (krbret != 0) { 608 PAM_LOG("Error krb5_init_context() failed"); 609 return (PAM_PERM_DENIED); 610 } 611 612 PAM_LOG("Context initialised"); 613 614 krbret = krb5_cc_resolve(pam_context, (const char *)ccache_name, &ccache); 615 if (krbret != 0) { 616 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)ccache_name, 617 krb5_get_err_text(pam_context, krbret)); 618 krb5_free_context(pam_context); 619 return (PAM_PERM_DENIED); 620 } 621 622 PAM_LOG("Got ccache %s", (const char *)ccache_name); 623 624 625 krbret = krb5_cc_get_principal(pam_context, ccache, &princ); 626 if (krbret != 0) { 627 PAM_LOG("Error krb5_cc_get_principal(): %s", 628 krb5_get_err_text(pam_context, krbret)); 629 retval = PAM_PERM_DENIED;; 630 goto cleanup; 631 } 632 633 PAM_LOG("Got principal"); 634 635 if (krb5_kuserok(pam_context, princ, (const char *)user)) 636 retval = PAM_SUCCESS; 637 else 638 retval = PAM_PERM_DENIED; 639 krb5_free_principal(pam_context, princ); 640 641 PAM_LOG("Done kuserok()"); 642 643cleanup: 644 krb5_free_context(pam_context); 645 PAM_LOG("Done cleanup"); 646 647 return (retval); 648 649} 650 651/* 652 * password management 653 */ 654PAM_EXTERN int 655pam_sm_chauthtok(pam_handle_t *pamh, int flags, 656 int argc __unused, const char *argv[] __unused) 657{ 658 krb5_error_code krbret; 659 krb5_context pam_context; 660 krb5_creds creds; 661 krb5_principal princ; 662 krb5_get_init_creds_opt opts; 663 krb5_data result_code_string, result_string; 664 int result_code, retval; 665 const char *pass; 666 const void *user; 667 char *princ_name, *passdup; 668 669 if (!(flags & PAM_UPDATE_AUTHTOK)) 670 return (PAM_AUTHTOK_ERR); 671 672 retval = pam_get_item(pamh, PAM_USER, &user); 673 if (retval != PAM_SUCCESS) 674 return (retval); 675 676 PAM_LOG("Got user: %s", (const char *)user); 677 678 krbret = krb5_init_context(&pam_context); 679 if (krbret != 0) { 680 PAM_LOG("Error krb5_init_context() failed"); 681 return (PAM_SERVICE_ERR); 682 } 683 684 PAM_LOG("Context initialised"); 685 686 krb5_get_init_creds_opt_init(&opts); 687 688 PAM_LOG("Credentials options initialised"); 689 690 /* Get principal name */ 691 krbret = krb5_parse_name(pam_context, (const char *)user, &princ); 692 if (krbret != 0) { 693 PAM_LOG("Error krb5_parse_name(): %s", 694 krb5_get_err_text(pam_context, krbret)); 695 retval = PAM_USER_UNKNOWN; 696 goto cleanup3; 697 } 698 699 /* Now convert the principal name into something human readable */ 700 princ_name = NULL; 701 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 702 if (krbret != 0) { 703 PAM_LOG("Error krb5_unparse_name(): %s", 704 krb5_get_err_text(pam_context, krbret)); 705 retval = PAM_SERVICE_ERR; 706 goto cleanup2; 707 } 708 709 PAM_LOG("Got principal: %s", princ_name); 710 711 /* Get password */ 712 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT); 713 if (retval != PAM_SUCCESS) 714 goto cleanup2; 715 716 PAM_LOG("Got password"); 717 718 memset(&creds, 0, sizeof(krb5_creds)); 719 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 720 pass, NULL, pamh, 0, "kadmin/changepw", &opts); 721 if (krbret != 0) { 722 PAM_LOG("Error krb5_get_init_creds_password(): %s", 723 krb5_get_err_text(pam_context, krbret)); 724 retval = PAM_AUTH_ERR; 725 goto cleanup2; 726 } 727 728 PAM_LOG("Credentials established"); 729 730 /* Now get the new password */ 731 for (;;) { 732 retval = pam_get_authtok(pamh, 733 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 734 if (retval != PAM_TRY_AGAIN) 735 break; 736 pam_error(pamh, "Mismatch; try again, EOF to quit."); 737 } 738 if (retval != PAM_SUCCESS) 739 goto cleanup; 740 741 PAM_LOG("Got new password"); 742 743 /* Change it */ 744 if ((passdup = strdup(pass)) == NULL) { 745 retval = PAM_BUF_ERR; 746 goto cleanup; 747 } 748 krbret = krb5_change_password(pam_context, &creds, passdup, 749 &result_code, &result_code_string, &result_string); 750 free(passdup); 751 if (krbret != 0) { 752 PAM_LOG("Error krb5_change_password(): %s", 753 krb5_get_err_text(pam_context, krbret)); 754 retval = PAM_AUTHTOK_ERR; 755 goto cleanup; 756 } 757 if (result_code) { 758 PAM_LOG("Error krb5_change_password(): (result_code)"); 759 retval = PAM_AUTHTOK_ERR; 760 goto cleanup; 761 } 762 763 PAM_LOG("Password changed"); 764 765 if (result_string.data) 766 free(result_string.data); 767 if (result_code_string.data) 768 free(result_code_string.data); 769 770cleanup: 771 krb5_free_cred_contents(pam_context, &creds); 772 PAM_LOG("Done cleanup"); 773cleanup2: 774 krb5_free_principal(pam_context, princ); 775 PAM_LOG("Done cleanup2"); 776cleanup3: 777 if (princ_name) 778 free(princ_name); 779 780 krb5_free_context(pam_context); 781 782 PAM_LOG("Done cleanup3"); 783 784 return (retval); 785} 786 787PAM_MODULE_ENTRY("pam_krb5"); 788 789/* 790 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 791 * Modified by Sam Hartman <hartmans@mit.edu> to support PAM services 792 * for Debian. 793 * 794 * Verify the Kerberos ticket-granting ticket just retrieved for the 795 * user. If the Kerberos server doesn't respond, assume the user is 796 * trying to fake us out (since we DID just get a TGT from what is 797 * supposedly our KDC). If the host/<host> service is unknown (i.e., 798 * the local keytab doesn't have it), and we cannot find another 799 * service we do have, let her in. 800 * 801 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 802 */ 803/* ARGSUSED */ 804static int 805verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 806 char *pam_service, int debug) 807{ 808 krb5_error_code retval; 809 krb5_principal princ; 810 krb5_keyblock *keyblock; 811 krb5_data packet; 812 krb5_auth_context auth_context; 813 char phost[BUFSIZ]; 814 const char *services[3], **service; 815 816 packet.data = 0; 817 818 /* If possible we want to try and verify the ticket we have 819 * received against a keytab. We will try multiple service 820 * principals, including at least the host principal and the PAM 821 * service principal. The host principal is preferred because access 822 * to that key is generally sufficient to compromise root, while the 823 * service key for this PAM service may be less carefully guarded. 824 * It is important to check the keytab first before the KDC so we do 825 * not get spoofed by a fake KDC. 826 */ 827 services[0] = "host"; 828 services[1] = pam_service; 829 services[2] = NULL; 830 keyblock = 0; 831 retval = -1; 832 for (service = &services[0]; *service != NULL; service++) { 833 retval = krb5_sname_to_principal(context, NULL, *service, 834 KRB5_NT_SRV_HST, &princ); 835 if (retval != 0) { 836 if (debug) 837 syslog(LOG_DEBUG, 838 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 839 "krb5_sname_to_principal()", 840 krb5_get_err_text(context, retval)); 841 return -1; 842 } 843 844 /* Extract the name directly. */ 845 strncpy(phost, compat_princ_component(context, princ, 1), 846 BUFSIZ); 847 phost[BUFSIZ - 1] = '\0'; 848 849 /* 850 * Do we have service/<host> keys? 851 * (use default/configured keytab, kvno IGNORE_VNO to get the 852 * first match, and ignore enctype.) 853 */ 854 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 855 &keyblock); 856 if (retval != 0) 857 continue; 858 break; 859 } 860 if (retval != 0) { /* failed to find key */ 861 /* Keytab or service key does not exist */ 862 if (debug) 863 syslog(LOG_DEBUG, 864 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 865 "krb5_kt_read_service_key()", 866 krb5_get_err_text(context, retval)); 867 retval = 0; 868 goto cleanup; 869 } 870 if (keyblock) 871 krb5_free_keyblock(context, keyblock); 872 873 /* Talk to the kdc and construct the ticket. */ 874 auth_context = NULL; 875 retval = krb5_mk_req(context, &auth_context, 0, *service, phost, 876 NULL, ccache, &packet); 877 if (auth_context) { 878 krb5_auth_con_free(context, auth_context); 879 auth_context = NULL; /* setup for rd_req */ 880 } 881 if (retval) { 882 if (debug) 883 syslog(LOG_DEBUG, 884 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 885 "krb5_mk_req()", 886 krb5_get_err_text(context, retval)); 887 retval = -1; 888 goto cleanup; 889 } 890 891 /* Try to use the ticket. */ 892 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 893 NULL, NULL); 894 if (retval) { 895 if (debug) 896 syslog(LOG_DEBUG, 897 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 898 "krb5_rd_req()", 899 krb5_get_err_text(context, retval)); 900 retval = -1; 901 } 902 else 903 retval = 1; 904 905cleanup: 906 if (packet.data) 907 compat_free_data_contents(context, &packet); 908 krb5_free_principal(context, princ); 909 return retval; 910} 911 912/* Free the memory for cache_name. Called by pam_end() */ 913/* ARGSUSED */ 914static void 915cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 916{ 917 krb5_context pam_context; 918 krb5_ccache ccache; 919 krb5_error_code krbret; 920 921 if (krb5_init_context(&pam_context)) 922 return; 923 924 krbret = krb5_cc_resolve(pam_context, data, &ccache); 925 if (krbret == 0) 926 krb5_cc_destroy(pam_context, ccache); 927 krb5_free_context(pam_context); 928 free(data); 929} 930 931#ifdef COMPAT_HEIMDAL 932#ifdef COMPAT_MIT 933#error This cannot be MIT and Heimdal compatible! 934#endif 935#endif 936 937#ifndef COMPAT_HEIMDAL 938#ifndef COMPAT_MIT 939#error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 940#endif 941#endif 942 943#ifdef COMPAT_HEIMDAL 944/* ARGSUSED */ 945static const char * 946compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 947{ 948 return princ->name.name_string.val[n]; 949} 950 951/* ARGSUSED */ 952static void 953compat_free_data_contents(krb5_context context __unused, krb5_data * data) 954{ 955 krb5_xfree(data->data); 956} 957#endif 958 959#ifdef COMPAT_MIT 960static const char * 961compat_princ_component(krb5_context context, krb5_principal princ, int n) 962{ 963 return krb5_princ_component(context, princ, n)->data; 964} 965 966static void 967compat_free_data_contents(krb5_context context, krb5_data * data) 968{ 969 krb5_free_data_contents(context, data); 970} 971#endif 972