pam_krb5.c revision 140747
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 140747 2005-01-24 16:49:50Z rwatson $"); 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{ 336 337 krb5_error_code krbret; 338 krb5_context pam_context; 339 krb5_principal princ; 340 krb5_creds creds; 341 krb5_ccache ccache_temp, ccache_perm; 342 krb5_cc_cursor cursor; 343 struct passwd *pwd = NULL; 344 int retval; 345 const char *cache_name, *q; 346 const void *user; 347 void *cache_data; 348 char *cache_name_buf = NULL, *p; 349 350 uid_t euid; 351 gid_t egid; 352 353 if (flags & PAM_DELETE_CRED) 354 return (PAM_SUCCESS); 355 356 if (flags & PAM_REFRESH_CRED) 357 return (PAM_SUCCESS); 358 359 if (flags & PAM_REINITIALIZE_CRED) 360 return (PAM_SUCCESS); 361 362 if (!(flags & PAM_ESTABLISH_CRED)) 363 return (PAM_SERVICE_ERR); 364 365 /* If a persistent cache isn't desired, stop now. */ 366 if (openpam_get_option(pamh, PAM_OPT_NO_CCACHE)) 367 return (PAM_SUCCESS); 368 369 PAM_LOG("Establishing credentials"); 370 371 /* Get username */ 372 retval = pam_get_item(pamh, PAM_USER, &user); 373 if (retval != PAM_SUCCESS) 374 return (retval); 375 376 PAM_LOG("Got user: %s", (const char *)user); 377 378 krbret = krb5_init_context(&pam_context); 379 if (krbret != 0) { 380 PAM_LOG("Error krb5_init_context() failed"); 381 return (PAM_SERVICE_ERR); 382 } 383 384 PAM_LOG("Context initialised"); 385 386 euid = geteuid(); /* Usually 0 */ 387 egid = getegid(); 388 389 PAM_LOG("Got euid, egid: %d %d", euid, egid); 390 391 /* Retrieve the temporary cache */ 392 retval = pam_get_data(pamh, "ccache", &cache_data); 393 if (retval != PAM_SUCCESS) { 394 retval = PAM_CRED_UNAVAIL; 395 goto cleanup3; 396 } 397 krbret = krb5_cc_resolve(pam_context, cache_data, &ccache_temp); 398 if (krbret != 0) { 399 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)cache_data, 400 krb5_get_err_text(pam_context, krbret)); 401 retval = PAM_SERVICE_ERR; 402 goto cleanup3; 403 } 404 405 /* Get the uid. This should exist. */ 406 pwd = getpwnam(user); 407 if (pwd == NULL) { 408 retval = PAM_USER_UNKNOWN; 409 goto cleanup3; 410 } 411 412 PAM_LOG("Done getpwnam()"); 413 414 /* Avoid following a symlink as root */ 415 if (setegid(pwd->pw_gid)) { 416 retval = PAM_SERVICE_ERR; 417 goto cleanup3; 418 } 419 if (seteuid(pwd->pw_uid)) { 420 retval = PAM_SERVICE_ERR; 421 goto cleanup3; 422 } 423 424 PAM_LOG("Done setegid() & seteuid()"); 425 426 /* Get the cache name */ 427 cache_name = openpam_get_option(pamh, PAM_OPT_CCACHE); 428 if (cache_name == NULL) { 429 asprintf(&cache_name_buf, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 430 cache_name = cache_name_buf; 431 } 432 433 p = calloc(PATH_MAX + 16, sizeof(char)); 434 q = cache_name; 435 436 if (p == NULL) { 437 PAM_LOG("Error malloc(): failure"); 438 retval = PAM_BUF_ERR; 439 goto cleanup3; 440 } 441 cache_name = p; 442 443 /* convert %u and %p */ 444 while (*q) { 445 if (*q == '%') { 446 q++; 447 if (*q == 'u') { 448 sprintf(p, "%d", pwd->pw_uid); 449 p += strlen(p); 450 } 451 else if (*q == 'p') { 452 sprintf(p, "%d", getpid()); 453 p += strlen(p); 454 } 455 else { 456 /* Not a special token */ 457 *p++ = '%'; 458 q--; 459 } 460 q++; 461 } 462 else { 463 *p++ = *q++; 464 } 465 } 466 467 PAM_LOG("Got cache_name: %s", cache_name); 468 469 /* Initialize the new ccache */ 470 krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ); 471 if (krbret != 0) { 472 PAM_LOG("Error krb5_cc_get_principal(): %s", 473 krb5_get_err_text(pam_context, krbret)); 474 retval = PAM_SERVICE_ERR; 475 goto cleanup3; 476 } 477 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm); 478 if (krbret != 0) { 479 PAM_LOG("Error krb5_cc_resolve(): %s", 480 krb5_get_err_text(pam_context, krbret)); 481 retval = PAM_SERVICE_ERR; 482 goto cleanup2; 483 } 484 krbret = krb5_cc_initialize(pam_context, ccache_perm, princ); 485 if (krbret != 0) { 486 PAM_LOG("Error krb5_cc_initialize(): %s", 487 krb5_get_err_text(pam_context, krbret)); 488 retval = PAM_SERVICE_ERR; 489 goto cleanup2; 490 } 491 492 PAM_LOG("Cache initialised"); 493 494 /* Prepare for iteration over creds */ 495 krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor); 496 if (krbret != 0) { 497 PAM_LOG("Error krb5_cc_start_seq_get(): %s", 498 krb5_get_err_text(pam_context, krbret)); 499 krb5_cc_destroy(pam_context, ccache_perm); 500 retval = PAM_SERVICE_ERR; 501 goto cleanup2; 502 } 503 504 PAM_LOG("Prepared for iteration"); 505 506 /* Copy the creds (should be two of them) */ 507 while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp, 508 &cursor, &creds) == 0)) { 509 krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds); 510 if (krbret != 0) { 511 PAM_LOG("Error krb5_cc_store_cred(): %s", 512 krb5_get_err_text(pam_context, krbret)); 513 krb5_cc_destroy(pam_context, ccache_perm); 514 krb5_free_cred_contents(pam_context, &creds); 515 retval = PAM_SERVICE_ERR; 516 goto cleanup2; 517 } 518 krb5_free_cred_contents(pam_context, &creds); 519 PAM_LOG("Iteration"); 520 } 521 krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor); 522 523 PAM_LOG("Done iterating"); 524 525 if (strstr(cache_name, "FILE:") == cache_name) { 526 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 527 PAM_LOG("Error chown(): %s", strerror(errno)); 528 krb5_cc_destroy(pam_context, ccache_perm); 529 retval = PAM_SERVICE_ERR; 530 goto cleanup2; 531 } 532 PAM_LOG("Done chown()"); 533 534 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 535 PAM_LOG("Error chmod(): %s", strerror(errno)); 536 krb5_cc_destroy(pam_context, ccache_perm); 537 retval = PAM_SERVICE_ERR; 538 goto cleanup2; 539 } 540 PAM_LOG("Done chmod()"); 541 } 542 543 krb5_cc_close(pam_context, ccache_perm); 544 545 PAM_LOG("Cache closed"); 546 547 retval = pam_setenv(pamh, "KRB5CCNAME", cache_name, 1); 548 if (retval != PAM_SUCCESS) { 549 PAM_LOG("Error pam_setenv(): %s", pam_strerror(pamh, retval)); 550 krb5_cc_destroy(pam_context, ccache_perm); 551 retval = PAM_SERVICE_ERR; 552 goto cleanup2; 553 } 554 555 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 556 557cleanup2: 558 krb5_free_principal(pam_context, princ); 559 PAM_LOG("Done cleanup2"); 560cleanup3: 561 krb5_free_context(pam_context); 562 PAM_LOG("Done cleanup3"); 563 564 seteuid(euid); 565 setegid(egid); 566 567 PAM_LOG("Done seteuid() & setegid()"); 568 569 if (cache_name_buf != NULL) 570 free(cache_name_buf); 571 572 return (retval); 573} 574 575/* 576 * account management 577 */ 578PAM_EXTERN int 579pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 580 int argc __unused, const char *argv[] __unused) 581{ 582 krb5_error_code krbret; 583 krb5_context pam_context; 584 krb5_ccache ccache; 585 krb5_principal princ; 586 int retval; 587 const void *user; 588 void *ccache_name; 589 590 retval = pam_get_item(pamh, PAM_USER, &user); 591 if (retval != PAM_SUCCESS) 592 return (retval); 593 594 PAM_LOG("Got user: %s", (const char *)user); 595 596 retval = pam_get_data(pamh, "ccache", &ccache_name); 597 if (retval != PAM_SUCCESS) 598 return (PAM_SUCCESS); 599 600 PAM_LOG("Got credentials"); 601 602 krbret = krb5_init_context(&pam_context); 603 if (krbret != 0) { 604 PAM_LOG("Error krb5_init_context() failed"); 605 return (PAM_PERM_DENIED); 606 } 607 608 PAM_LOG("Context initialised"); 609 610 krbret = krb5_cc_resolve(pam_context, (const char *)ccache_name, &ccache); 611 if (krbret != 0) { 612 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)ccache_name, 613 krb5_get_err_text(pam_context, krbret)); 614 krb5_free_context(pam_context); 615 return (PAM_PERM_DENIED); 616 } 617 618 PAM_LOG("Got ccache %s", (const char *)ccache_name); 619 620 621 krbret = krb5_cc_get_principal(pam_context, ccache, &princ); 622 if (krbret != 0) { 623 PAM_LOG("Error krb5_cc_get_principal(): %s", 624 krb5_get_err_text(pam_context, krbret)); 625 retval = PAM_PERM_DENIED;; 626 goto cleanup; 627 } 628 629 PAM_LOG("Got principal"); 630 631 if (krb5_kuserok(pam_context, princ, (const char *)user)) 632 retval = PAM_SUCCESS; 633 else 634 retval = PAM_PERM_DENIED; 635 krb5_free_principal(pam_context, princ); 636 637 PAM_LOG("Done kuserok()"); 638 639cleanup: 640 krb5_free_context(pam_context); 641 PAM_LOG("Done cleanup"); 642 643 return (retval); 644 645} 646 647/* 648 * password management 649 */ 650PAM_EXTERN int 651pam_sm_chauthtok(pam_handle_t *pamh, int flags, 652 int argc __unused, const char *argv[] __unused) 653{ 654 krb5_error_code krbret; 655 krb5_context pam_context; 656 krb5_creds creds; 657 krb5_principal princ; 658 krb5_get_init_creds_opt opts; 659 krb5_data result_code_string, result_string; 660 int result_code, retval; 661 const char *pass; 662 const void *user; 663 char *princ_name, *passdup; 664 665 if (!(flags & PAM_UPDATE_AUTHTOK)) 666 return (PAM_AUTHTOK_ERR); 667 668 retval = pam_get_item(pamh, PAM_USER, &user); 669 if (retval != PAM_SUCCESS) 670 return (retval); 671 672 PAM_LOG("Got user: %s", (const char *)user); 673 674 krbret = krb5_init_context(&pam_context); 675 if (krbret != 0) { 676 PAM_LOG("Error krb5_init_context() failed"); 677 return (PAM_SERVICE_ERR); 678 } 679 680 PAM_LOG("Context initialised"); 681 682 krb5_get_init_creds_opt_init(&opts); 683 684 PAM_LOG("Credentials options initialised"); 685 686 /* Get principal name */ 687 krbret = krb5_parse_name(pam_context, (const char *)user, &princ); 688 if (krbret != 0) { 689 PAM_LOG("Error krb5_parse_name(): %s", 690 krb5_get_err_text(pam_context, krbret)); 691 retval = PAM_USER_UNKNOWN; 692 goto cleanup3; 693 } 694 695 /* Now convert the principal name into something human readable */ 696 princ_name = NULL; 697 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 698 if (krbret != 0) { 699 PAM_LOG("Error krb5_unparse_name(): %s", 700 krb5_get_err_text(pam_context, krbret)); 701 retval = PAM_SERVICE_ERR; 702 goto cleanup2; 703 } 704 705 PAM_LOG("Got principal: %s", princ_name); 706 707 /* Get password */ 708 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT); 709 if (retval != PAM_SUCCESS) 710 goto cleanup2; 711 712 PAM_LOG("Got password"); 713 714 memset(&creds, 0, sizeof(krb5_creds)); 715 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 716 pass, NULL, pamh, 0, "kadmin/changepw", &opts); 717 if (krbret != 0) { 718 PAM_LOG("Error krb5_get_init_creds_password(): %s", 719 krb5_get_err_text(pam_context, krbret)); 720 retval = PAM_AUTH_ERR; 721 goto cleanup2; 722 } 723 724 PAM_LOG("Credentials established"); 725 726 /* Now get the new password */ 727 for (;;) { 728 retval = pam_get_authtok(pamh, 729 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 730 if (retval != PAM_TRY_AGAIN) 731 break; 732 pam_error(pamh, "Mismatch; try again, EOF to quit."); 733 } 734 if (retval != PAM_SUCCESS) 735 goto cleanup; 736 737 PAM_LOG("Got new password"); 738 739 /* Change it */ 740 if ((passdup = strdup(pass)) == NULL) { 741 retval = PAM_BUF_ERR; 742 goto cleanup; 743 } 744 krbret = krb5_change_password(pam_context, &creds, passdup, 745 &result_code, &result_code_string, &result_string); 746 free(passdup); 747 if (krbret != 0) { 748 PAM_LOG("Error krb5_change_password(): %s", 749 krb5_get_err_text(pam_context, krbret)); 750 retval = PAM_AUTHTOK_ERR; 751 goto cleanup; 752 } 753 if (result_code) { 754 PAM_LOG("Error krb5_change_password(): (result_code)"); 755 retval = PAM_AUTHTOK_ERR; 756 goto cleanup; 757 } 758 759 PAM_LOG("Password changed"); 760 761 if (result_string.data) 762 free(result_string.data); 763 if (result_code_string.data) 764 free(result_code_string.data); 765 766cleanup: 767 krb5_free_cred_contents(pam_context, &creds); 768 PAM_LOG("Done cleanup"); 769cleanup2: 770 krb5_free_principal(pam_context, princ); 771 PAM_LOG("Done cleanup2"); 772cleanup3: 773 if (princ_name) 774 free(princ_name); 775 776 krb5_free_context(pam_context); 777 778 PAM_LOG("Done cleanup3"); 779 780 return (retval); 781} 782 783PAM_MODULE_ENTRY("pam_krb5"); 784 785/* 786 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 787 * Modified by Sam Hartman <hartmans@mit.edu> to support PAM services 788 * for Debian. 789 * 790 * Verify the Kerberos ticket-granting ticket just retrieved for the 791 * user. If the Kerberos server doesn't respond, assume the user is 792 * trying to fake us out (since we DID just get a TGT from what is 793 * supposedly our KDC). If the host/<host> service is unknown (i.e., 794 * the local keytab doesn't have it), and we cannot find another 795 * service we do have, let her in. 796 * 797 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 798 */ 799/* ARGSUSED */ 800static int 801verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 802 char *pam_service, int debug) 803{ 804 krb5_error_code retval; 805 krb5_principal princ; 806 krb5_keyblock *keyblock; 807 krb5_data packet; 808 krb5_auth_context auth_context; 809 char phost[BUFSIZ]; 810 const char *services[3], **service; 811 812 packet.data = 0; 813 814 /* If possible we want to try and verify the ticket we have 815 * received against a keytab. We will try multiple service 816 * principals, including at least the host principal and the PAM 817 * service principal. The host principal is preferred because access 818 * to that key is generally sufficient to compromise root, while the 819 * service key for this PAM service may be less carefully guarded. 820 * It is important to check the keytab first before the KDC so we do 821 * not get spoofed by a fake KDC. 822 */ 823 services[0] = "host"; 824 services[1] = pam_service; 825 services[2] = NULL; 826 keyblock = 0; 827 retval = -1; 828 for (service = &services[0]; *service != NULL; service++) { 829 retval = krb5_sname_to_principal(context, NULL, *service, 830 KRB5_NT_SRV_HST, &princ); 831 if (retval != 0) { 832 if (debug) 833 syslog(LOG_DEBUG, 834 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 835 "krb5_sname_to_principal()", 836 krb5_get_err_text(context, retval)); 837 return -1; 838 } 839 840 /* Extract the name directly. */ 841 strncpy(phost, compat_princ_component(context, princ, 1), 842 BUFSIZ); 843 phost[BUFSIZ - 1] = '\0'; 844 845 /* 846 * Do we have service/<host> keys? 847 * (use default/configured keytab, kvno IGNORE_VNO to get the 848 * first match, and ignore enctype.) 849 */ 850 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 851 &keyblock); 852 if (retval != 0) 853 continue; 854 break; 855 } 856 if (retval != 0) { /* failed to find key */ 857 /* Keytab or service key does not exist */ 858 if (debug) 859 syslog(LOG_DEBUG, 860 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 861 "krb5_kt_read_service_key()", 862 krb5_get_err_text(context, retval)); 863 retval = 0; 864 goto cleanup; 865 } 866 if (keyblock) 867 krb5_free_keyblock(context, keyblock); 868 869 /* Talk to the kdc and construct the ticket. */ 870 auth_context = NULL; 871 retval = krb5_mk_req(context, &auth_context, 0, *service, phost, 872 NULL, ccache, &packet); 873 if (auth_context) { 874 krb5_auth_con_free(context, auth_context); 875 auth_context = NULL; /* setup for rd_req */ 876 } 877 if (retval) { 878 if (debug) 879 syslog(LOG_DEBUG, 880 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 881 "krb5_mk_req()", 882 krb5_get_err_text(context, retval)); 883 retval = -1; 884 goto cleanup; 885 } 886 887 /* Try to use the ticket. */ 888 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 889 NULL, NULL); 890 if (retval) { 891 if (debug) 892 syslog(LOG_DEBUG, 893 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 894 "krb5_rd_req()", 895 krb5_get_err_text(context, retval)); 896 retval = -1; 897 } 898 else 899 retval = 1; 900 901cleanup: 902 if (packet.data) 903 compat_free_data_contents(context, &packet); 904 krb5_free_principal(context, princ); 905 return retval; 906} 907 908/* Free the memory for cache_name. Called by pam_end() */ 909/* ARGSUSED */ 910static void 911cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 912{ 913 krb5_context pam_context; 914 krb5_ccache ccache; 915 krb5_error_code krbret; 916 917 if (krb5_init_context(&pam_context)) 918 return; 919 920 krbret = krb5_cc_resolve(pam_context, data, &ccache); 921 if (krbret == 0) 922 krb5_cc_destroy(pam_context, ccache); 923 krb5_free_context(pam_context); 924 free(data); 925} 926 927#ifdef COMPAT_HEIMDAL 928#ifdef COMPAT_MIT 929#error This cannot be MIT and Heimdal compatible! 930#endif 931#endif 932 933#ifndef COMPAT_HEIMDAL 934#ifndef COMPAT_MIT 935#error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 936#endif 937#endif 938 939#ifdef COMPAT_HEIMDAL 940/* ARGSUSED */ 941static const char * 942compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 943{ 944 return princ->name.name_string.val[n]; 945} 946 947/* ARGSUSED */ 948static void 949compat_free_data_contents(krb5_context context __unused, krb5_data * data) 950{ 951 krb5_xfree(data->data); 952} 953#endif 954 955#ifdef COMPAT_MIT 956static const char * 957compat_princ_component(krb5_context context, krb5_principal princ, int n) 958{ 959 return krb5_princ_component(context, princ, n)->data; 960} 961 962static void 963compat_free_data_contents(krb5_context context, krb5_data * data) 964{ 965 krb5_free_data_contents(context, data); 966} 967#endif 968