pam_krb5.c revision 123454
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., 2002-2003. 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 123454 2003-12-11 15:48:09Z des $"); 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_FORWARDABLE "forwardable" 90#define PAM_OPT_NO_CCACHE "no_ccache" 91#define PAM_OPT_REUSE_CCACHE "reuse_ccache" 92 93/* 94 * authentication management 95 */ 96PAM_EXTERN int 97pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 98 int argc __unused, const char *argv[] __unused) 99{ 100 krb5_error_code krbret; 101 krb5_context pam_context; 102 krb5_creds creds; 103 krb5_principal princ; 104 krb5_ccache ccache; 105 krb5_get_init_creds_opt opts; 106 struct passwd *pwd; 107 int retval; 108 const char *user, *pass; 109 const void *sourceuser, *service, *item; 110 char *principal, *princ_name, *ccache_name, luser[32], *srvdup; 111 112 retval = pam_get_user(pamh, &user, USER_PROMPT); 113 if (retval != PAM_SUCCESS) 114 return (retval); 115 116 PAM_LOG("Got user: %s", user); 117 118 retval = pam_get_item(pamh, PAM_RUSER, &sourceuser); 119 if (retval != PAM_SUCCESS) 120 return (retval); 121 122 PAM_LOG("Got ruser: %s", (const char *)sourceuser); 123 124 service = NULL; 125 pam_get_item(pamh, PAM_SERVICE, &service); 126 if (service == NULL) 127 service = "unknown"; 128 129 PAM_LOG("Got service: %s", (const char *)service); 130 131 krbret = krb5_init_context(&pam_context); 132 if (krbret != 0) { 133 PAM_VERBOSE_ERROR("Kerberos 5 error"); 134 return (PAM_SERVICE_ERR); 135 } 136 137 PAM_LOG("Context initialised"); 138 139 krb5_get_init_creds_opt_init(&opts); 140 141 if (openpam_get_option(pamh, PAM_OPT_FORWARDABLE)) 142 krb5_get_init_creds_opt_set_forwardable(&opts, 1); 143 144 PAM_LOG("Credentials initialised"); 145 146 krbret = krb5_cc_register(pam_context, &krb5_mcc_ops, FALSE); 147 if (krbret != 0 && krbret != KRB5_CC_TYPE_EXISTS) { 148 PAM_VERBOSE_ERROR("Kerberos 5 error"); 149 retval = PAM_SERVICE_ERR; 150 goto cleanup3; 151 } 152 153 PAM_LOG("Done krb5_cc_register()"); 154 155 /* Get principal name */ 156 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) 157 asprintf(&principal, "%s/%s", (const char *)sourceuser, user); 158 else 159 principal = strdup(user); 160 161 PAM_LOG("Created principal: %s", principal); 162 163 krbret = krb5_parse_name(pam_context, principal, &princ); 164 free(principal); 165 if (krbret != 0) { 166 PAM_LOG("Error krb5_parse_name(): %s", 167 krb5_get_err_text(pam_context, krbret)); 168 PAM_VERBOSE_ERROR("Kerberos 5 error"); 169 retval = PAM_SERVICE_ERR; 170 goto cleanup3; 171 } 172 173 PAM_LOG("Done krb5_parse_name()"); 174 175 /* Now convert the principal name into something human readable */ 176 princ_name = NULL; 177 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 178 if (krbret != 0) { 179 PAM_LOG("Error krb5_unparse_name(): %s", 180 krb5_get_err_text(pam_context, krbret)); 181 PAM_VERBOSE_ERROR("Kerberos 5 error"); 182 retval = PAM_SERVICE_ERR; 183 goto cleanup2; 184 } 185 186 PAM_LOG("Got principal: %s", princ_name); 187 188 /* Get password */ 189 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT); 190 if (retval != PAM_SUCCESS) 191 goto cleanup2; 192 193 PAM_LOG("Got password"); 194 195 /* Verify the local user exists (AFTER getting the password) */ 196 if (strchr(user, '@')) { 197 /* get a local account name for this principal */ 198 krbret = krb5_aname_to_localname(pam_context, princ, 199 sizeof(luser), luser); 200 if (krbret != 0) { 201 PAM_VERBOSE_ERROR("Kerberos 5 error"); 202 PAM_LOG("Error krb5_aname_to_localname(): %s", 203 krb5_get_err_text(pam_context, krbret)); 204 retval = PAM_USER_UNKNOWN; 205 goto cleanup2; 206 } 207 208 retval = pam_set_item(pamh, PAM_USER, luser); 209 if (retval != PAM_SUCCESS) 210 goto cleanup2; 211 212 retval = pam_get_item(pamh, PAM_USER, &item); 213 if (retval != PAM_SUCCESS) 214 goto cleanup2; 215 216 PAM_LOG("PAM_USER Redone"); 217 } 218 219 pwd = getpwnam(user); 220 if (pwd == NULL) { 221 retval = PAM_USER_UNKNOWN; 222 goto cleanup2; 223 } 224 225 PAM_LOG("Done getpwnam()"); 226 227 /* Get a TGT */ 228 memset(&creds, 0, sizeof(krb5_creds)); 229 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 230 pass, NULL, pamh, 0, NULL, &opts); 231 if (krbret != 0) { 232 PAM_VERBOSE_ERROR("Kerberos 5 error"); 233 PAM_LOG("Error krb5_get_init_creds_password(): %s", 234 krb5_get_err_text(pam_context, krbret)); 235 retval = PAM_AUTH_ERR; 236 goto cleanup2; 237 } 238 239 PAM_LOG("Got TGT"); 240 241 /* Generate a temporary cache */ 242 krbret = krb5_cc_gen_new(pam_context, &krb5_mcc_ops, &ccache); 243 if (krbret != 0) { 244 PAM_VERBOSE_ERROR("Kerberos 5 error"); 245 PAM_LOG("Error krb5_cc_gen_new(): %s", 246 krb5_get_err_text(pam_context, krbret)); 247 retval = PAM_SERVICE_ERR; 248 goto cleanup; 249 } 250 krbret = krb5_cc_initialize(pam_context, ccache, princ); 251 if (krbret != 0) { 252 PAM_VERBOSE_ERROR("Kerberos 5 error"); 253 PAM_LOG("Error krb5_cc_initialize(): %s", 254 krb5_get_err_text(pam_context, krbret)); 255 retval = PAM_SERVICE_ERR; 256 goto cleanup; 257 } 258 krbret = krb5_cc_store_cred(pam_context, ccache, &creds); 259 if (krbret != 0) { 260 PAM_VERBOSE_ERROR("Kerberos 5 error"); 261 PAM_LOG("Error krb5_cc_store_cred(): %s", 262 krb5_get_err_text(pam_context, krbret)); 263 krb5_cc_destroy(pam_context, ccache); 264 retval = PAM_SERVICE_ERR; 265 goto cleanup; 266 } 267 268 PAM_LOG("Credentials stashed"); 269 270 /* Verify them */ 271 if ((srvdup = strdup(service)) == NULL) { 272 retval = PAM_BUF_ERR; 273 goto cleanup; 274 } 275 krbret = verify_krb_v5_tgt(pam_context, ccache, srvdup, 276 openpam_get_option(pamh, PAM_OPT_FORWARDABLE) ? 1 : 0); 277 free(srvdup); 278 if (krbret == -1) { 279 PAM_VERBOSE_ERROR("Kerberos 5 error"); 280 krb5_cc_destroy(pam_context, ccache); 281 retval = PAM_AUTH_ERR; 282 goto cleanup; 283 } 284 285 PAM_LOG("Credentials stash verified"); 286 287 retval = pam_get_data(pamh, "ccache", &item); 288 if (retval == PAM_SUCCESS) { 289 krb5_cc_destroy(pam_context, ccache); 290 PAM_VERBOSE_ERROR("Kerberos 5 error"); 291 retval = PAM_AUTH_ERR; 292 goto cleanup; 293 } 294 295 PAM_LOG("Credentials stash not pre-existing"); 296 297 asprintf(&ccache_name, "%s:%s", krb5_cc_get_type(pam_context, 298 ccache), krb5_cc_get_name(pam_context, ccache)); 299 if (ccache_name == NULL) { 300 PAM_VERBOSE_ERROR("Kerberos 5 error"); 301 retval = PAM_BUF_ERR; 302 goto cleanup; 303 } 304 retval = pam_set_data(pamh, "ccache", ccache_name, cleanup_cache); 305 if (retval != 0) { 306 krb5_cc_destroy(pam_context, ccache); 307 PAM_VERBOSE_ERROR("Kerberos 5 error"); 308 retval = PAM_SERVICE_ERR; 309 goto cleanup; 310 } 311 312 PAM_LOG("Credentials stash saved"); 313 314cleanup: 315 krb5_free_cred_contents(pam_context, &creds); 316 PAM_LOG("Done cleanup"); 317cleanup2: 318 krb5_free_principal(pam_context, princ); 319 PAM_LOG("Done cleanup2"); 320cleanup3: 321 if (princ_name) 322 free(princ_name); 323 324 krb5_free_context(pam_context); 325 326 PAM_LOG("Done cleanup3"); 327 328 if (retval != PAM_SUCCESS) 329 PAM_VERBOSE_ERROR("Kerberos 5 refuses you"); 330 331 return (retval); 332} 333 334PAM_EXTERN int 335pam_sm_setcred(pam_handle_t *pamh, int flags, 336 int argc __unused, const char *argv[] __unused) 337{ 338 339 krb5_error_code krbret; 340 krb5_context pam_context; 341 krb5_principal princ; 342 krb5_creds creds; 343 krb5_ccache ccache_temp, ccache_perm; 344 krb5_cc_cursor cursor; 345 struct passwd *pwd = NULL; 346 int retval; 347 const char *cache_name, *q; 348 const void *user, *cache_data; 349 char *cache_name_buf = NULL, *p; 350 351 uid_t euid; 352 gid_t egid; 353 354 if (flags & PAM_DELETE_CRED) 355 return (PAM_SUCCESS); 356 357 if (flags & PAM_REFRESH_CRED) 358 return (PAM_SUCCESS); 359 360 if (flags & PAM_REINITIALIZE_CRED) 361 return (PAM_SUCCESS); 362 363 if (!(flags & PAM_ESTABLISH_CRED)) 364 return (PAM_SERVICE_ERR); 365 366 PAM_LOG("Establishing credentials"); 367 368 /* Get username */ 369 retval = pam_get_item(pamh, PAM_USER, &user); 370 if (retval != PAM_SUCCESS) 371 return (retval); 372 373 PAM_LOG("Got user: %s", (const char *)user); 374 375 krbret = krb5_init_context(&pam_context); 376 if (krbret != 0) { 377 PAM_LOG("Error krb5_init_context() failed"); 378 return (PAM_SERVICE_ERR); 379 } 380 381 PAM_LOG("Context initialised"); 382 383 euid = geteuid(); /* Usually 0 */ 384 egid = getegid(); 385 386 PAM_LOG("Got euid, egid: %d %d", euid, egid); 387 388 /* Retrieve the temporary cache */ 389 retval = pam_get_data(pamh, "ccache", &cache_data); 390 if (retval != PAM_SUCCESS) { 391 retval = PAM_CRED_UNAVAIL; 392 goto cleanup3; 393 } 394 krbret = krb5_cc_resolve(pam_context, cache_data, &ccache_temp); 395 if (krbret != 0) { 396 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)cache_data, 397 krb5_get_err_text(pam_context, krbret)); 398 retval = PAM_SERVICE_ERR; 399 goto cleanup3; 400 } 401 402 /* Get the uid. This should exist. */ 403 pwd = getpwnam(user); 404 if (pwd == NULL) { 405 retval = PAM_USER_UNKNOWN; 406 goto cleanup3; 407 } 408 409 PAM_LOG("Done getpwnam()"); 410 411 /* Avoid following a symlink as root */ 412 if (setegid(pwd->pw_gid)) { 413 retval = PAM_SERVICE_ERR; 414 goto cleanup3; 415 } 416 if (seteuid(pwd->pw_uid)) { 417 retval = PAM_SERVICE_ERR; 418 goto cleanup3; 419 } 420 421 PAM_LOG("Done setegid() & seteuid()"); 422 423 /* Get the cache name */ 424 cache_name = openpam_get_option(pamh, PAM_OPT_CCACHE); 425 if (cache_name == NULL) { 426 asprintf(&cache_name_buf, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 427 cache_name = cache_name_buf; 428 } 429 430 p = calloc(PATH_MAX + 16, sizeof(char)); 431 q = cache_name; 432 433 if (p == NULL) { 434 PAM_LOG("Error malloc(): failure"); 435 retval = PAM_BUF_ERR; 436 goto cleanup3; 437 } 438 cache_name = p; 439 440 /* convert %u and %p */ 441 while (*q) { 442 if (*q == '%') { 443 q++; 444 if (*q == 'u') { 445 sprintf(p, "%d", pwd->pw_uid); 446 p += strlen(p); 447 } 448 else if (*q == 'p') { 449 sprintf(p, "%d", getpid()); 450 p += strlen(p); 451 } 452 else { 453 /* Not a special token */ 454 *p++ = '%'; 455 q--; 456 } 457 q++; 458 } 459 else { 460 *p++ = *q++; 461 } 462 } 463 464 PAM_LOG("Got cache_name: %s", cache_name); 465 466 /* Initialize the new ccache */ 467 krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ); 468 if (krbret != 0) { 469 PAM_LOG("Error krb5_cc_get_principal(): %s", 470 krb5_get_err_text(pam_context, krbret)); 471 retval = PAM_SERVICE_ERR; 472 goto cleanup3; 473 } 474 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm); 475 if (krbret != 0) { 476 PAM_LOG("Error krb5_cc_resolve(): %s", 477 krb5_get_err_text(pam_context, krbret)); 478 retval = PAM_SERVICE_ERR; 479 goto cleanup2; 480 } 481 krbret = krb5_cc_initialize(pam_context, ccache_perm, princ); 482 if (krbret != 0) { 483 PAM_LOG("Error krb5_cc_initialize(): %s", 484 krb5_get_err_text(pam_context, krbret)); 485 retval = PAM_SERVICE_ERR; 486 goto cleanup2; 487 } 488 489 PAM_LOG("Cache initialised"); 490 491 /* Prepare for iteration over creds */ 492 krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor); 493 if (krbret != 0) { 494 PAM_LOG("Error krb5_cc_start_seq_get(): %s", 495 krb5_get_err_text(pam_context, krbret)); 496 krb5_cc_destroy(pam_context, ccache_perm); 497 retval = PAM_SERVICE_ERR; 498 goto cleanup2; 499 } 500 501 PAM_LOG("Prepared for iteration"); 502 503 /* Copy the creds (should be two of them) */ 504 while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp, 505 &cursor, &creds) == 0)) { 506 krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds); 507 if (krbret != 0) { 508 PAM_LOG("Error krb5_cc_store_cred(): %s", 509 krb5_get_err_text(pam_context, krbret)); 510 krb5_cc_destroy(pam_context, ccache_perm); 511 krb5_free_cred_contents(pam_context, &creds); 512 retval = PAM_SERVICE_ERR; 513 goto cleanup2; 514 } 515 krb5_free_cred_contents(pam_context, &creds); 516 PAM_LOG("Iteration"); 517 } 518 krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor); 519 520 PAM_LOG("Done iterating"); 521 522 if (strstr(cache_name, "FILE:") == cache_name) { 523 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 524 PAM_LOG("Error chown(): %s", strerror(errno)); 525 krb5_cc_destroy(pam_context, ccache_perm); 526 retval = PAM_SERVICE_ERR; 527 goto cleanup2; 528 } 529 PAM_LOG("Done chown()"); 530 531 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 532 PAM_LOG("Error chmod(): %s", strerror(errno)); 533 krb5_cc_destroy(pam_context, ccache_perm); 534 retval = PAM_SERVICE_ERR; 535 goto cleanup2; 536 } 537 PAM_LOG("Done chmod()"); 538 } 539 540 krb5_cc_close(pam_context, ccache_perm); 541 542 PAM_LOG("Cache closed"); 543 544 retval = pam_setenv(pamh, "KRB5CCNAME", cache_name, 1); 545 if (retval != PAM_SUCCESS) { 546 PAM_LOG("Error pam_setenv(): %s", pam_strerror(pamh, retval)); 547 krb5_cc_destroy(pam_context, ccache_perm); 548 retval = PAM_SERVICE_ERR; 549 goto cleanup2; 550 } 551 552 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 553 554cleanup2: 555 krb5_free_principal(pam_context, princ); 556 PAM_LOG("Done cleanup2"); 557cleanup3: 558 krb5_free_context(pam_context); 559 PAM_LOG("Done cleanup3"); 560 561 seteuid(euid); 562 setegid(egid); 563 564 PAM_LOG("Done seteuid() & setegid()"); 565 566 if (cache_name_buf != NULL) 567 free(cache_name_buf); 568 569 return (retval); 570} 571 572/* 573 * account management 574 */ 575PAM_EXTERN int 576pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 577 int argc __unused, const char *argv[] __unused) 578{ 579 krb5_error_code krbret; 580 krb5_context pam_context; 581 krb5_ccache ccache; 582 krb5_principal princ; 583 int retval; 584 const void *user, *ccache_name; 585 586 retval = pam_get_item(pamh, PAM_USER, &user); 587 if (retval != PAM_SUCCESS) 588 return (retval); 589 590 PAM_LOG("Got user: %s", (const char *)user); 591 592 retval = pam_get_data(pamh, "ccache", &ccache_name); 593 if (retval != PAM_SUCCESS) 594 return (PAM_SUCCESS); 595 596 PAM_LOG("Got credentials"); 597 598 krbret = krb5_init_context(&pam_context); 599 if (krbret != 0) { 600 PAM_LOG("Error krb5_init_context() failed"); 601 return (PAM_PERM_DENIED); 602 } 603 604 PAM_LOG("Context initialised"); 605 606 krbret = krb5_cc_resolve(pam_context, (const char *)ccache_name, &ccache); 607 if (krbret != 0) { 608 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)ccache_name, 609 krb5_get_err_text(pam_context, krbret)); 610 krb5_free_context(pam_context); 611 return (PAM_PERM_DENIED); 612 } 613 614 PAM_LOG("Got ccache %s", (const char *)ccache_name); 615 616 617 krbret = krb5_cc_get_principal(pam_context, ccache, &princ); 618 if (krbret != 0) { 619 PAM_LOG("Error krb5_cc_get_principal(): %s", 620 krb5_get_err_text(pam_context, krbret)); 621 retval = PAM_PERM_DENIED;; 622 goto cleanup; 623 } 624 625 PAM_LOG("Got principal"); 626 627 if (krb5_kuserok(pam_context, princ, (const char *)user)) 628 retval = PAM_SUCCESS; 629 else 630 retval = PAM_PERM_DENIED; 631 krb5_free_principal(pam_context, princ); 632 633 PAM_LOG("Done kuserok()"); 634 635cleanup: 636 krb5_free_context(pam_context); 637 PAM_LOG("Done cleanup"); 638 639 return (retval); 640 641} 642 643/* 644 * password management 645 */ 646PAM_EXTERN int 647pam_sm_chauthtok(pam_handle_t *pamh, int flags, 648 int argc __unused, const char *argv[] __unused) 649{ 650 krb5_error_code krbret; 651 krb5_context pam_context; 652 krb5_creds creds; 653 krb5_principal princ; 654 krb5_get_init_creds_opt opts; 655 krb5_data result_code_string, result_string; 656 int result_code, retval; 657 const char *pass; 658 const void *user; 659 char *princ_name, *passdup; 660 661 if (!(flags & PAM_UPDATE_AUTHTOK)) 662 return (PAM_AUTHTOK_ERR); 663 664 retval = pam_get_item(pamh, PAM_USER, &user); 665 if (retval != PAM_SUCCESS) 666 return (retval); 667 668 PAM_LOG("Got user: %s", (const char *)user); 669 670 krbret = krb5_init_context(&pam_context); 671 if (krbret != 0) { 672 PAM_LOG("Error krb5_init_context() failed"); 673 return (PAM_SERVICE_ERR); 674 } 675 676 PAM_LOG("Context initialised"); 677 678 krb5_get_init_creds_opt_init(&opts); 679 680 PAM_LOG("Credentials options initialised"); 681 682 /* Get principal name */ 683 krbret = krb5_parse_name(pam_context, (const char *)user, &princ); 684 if (krbret != 0) { 685 PAM_LOG("Error krb5_parse_name(): %s", 686 krb5_get_err_text(pam_context, krbret)); 687 retval = PAM_USER_UNKNOWN; 688 goto cleanup3; 689 } 690 691 /* Now convert the principal name into something human readable */ 692 princ_name = NULL; 693 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 694 if (krbret != 0) { 695 PAM_LOG("Error krb5_unparse_name(): %s", 696 krb5_get_err_text(pam_context, krbret)); 697 retval = PAM_SERVICE_ERR; 698 goto cleanup2; 699 } 700 701 PAM_LOG("Got principal: %s", princ_name); 702 703 /* Get password */ 704 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT); 705 if (retval != PAM_SUCCESS) 706 goto cleanup2; 707 708 PAM_LOG("Got password"); 709 710 memset(&creds, 0, sizeof(krb5_creds)); 711 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 712 pass, NULL, pamh, 0, "kadmin/changepw", &opts); 713 if (krbret != 0) { 714 PAM_LOG("Error krb5_get_init_creds_password()", 715 krb5_get_err_text(pam_context, krbret)); 716 retval = PAM_AUTH_ERR; 717 goto cleanup2; 718 } 719 720 PAM_LOG("Credentials established"); 721 722 /* Now get the new password */ 723 for (;;) { 724 retval = pam_get_authtok(pamh, 725 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 726 if (retval != PAM_TRY_AGAIN) 727 break; 728 pam_error(pamh, "Mismatch; try again, EOF to quit."); 729 } 730 if (retval != PAM_SUCCESS) 731 goto cleanup; 732 733 PAM_LOG("Got new password"); 734 735 /* Change it */ 736 if ((passdup = strdup(pass)) == NULL) { 737 retval = PAM_BUF_ERR; 738 goto cleanup; 739 } 740 krbret = krb5_change_password(pam_context, &creds, passdup, 741 &result_code, &result_code_string, &result_string); 742 free(passdup); 743 if (krbret != 0) { 744 PAM_LOG("Error krb5_change_password(): %s", 745 krb5_get_err_text(pam_context, krbret)); 746 retval = PAM_AUTHTOK_ERR; 747 goto cleanup; 748 } 749 if (result_code) { 750 PAM_LOG("Error krb5_change_password(): (result_code)"); 751 retval = PAM_AUTHTOK_ERR; 752 goto cleanup; 753 } 754 755 PAM_LOG("Password changed"); 756 757 if (result_string.data) 758 free(result_string.data); 759 if (result_code_string.data) 760 free(result_code_string.data); 761 762cleanup: 763 krb5_free_cred_contents(pam_context, &creds); 764 PAM_LOG("Done cleanup"); 765cleanup2: 766 krb5_free_principal(pam_context, princ); 767 PAM_LOG("Done cleanup2"); 768cleanup3: 769 if (princ_name) 770 free(princ_name); 771 772 krb5_free_context(pam_context); 773 774 PAM_LOG("Done cleanup3"); 775 776 return (retval); 777} 778 779PAM_MODULE_ENTRY("pam_krb5"); 780 781/* 782 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 783 * Modified by Sam Hartman <hartmans@mit.edu> to support PAM services 784 * for Debian. 785 * 786 * Verify the Kerberos ticket-granting ticket just retrieved for the 787 * user. If the Kerberos server doesn't respond, assume the user is 788 * trying to fake us out (since we DID just get a TGT from what is 789 * supposedly our KDC). If the host/<host> service is unknown (i.e., 790 * the local keytab doesn't have it), and we cannot find another 791 * service we do have, let her in. 792 * 793 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 794 */ 795/* ARGSUSED */ 796static int 797verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 798 char *pam_service, int debug) 799{ 800 krb5_error_code retval; 801 krb5_principal princ; 802 krb5_keyblock *keyblock; 803 krb5_data packet; 804 krb5_auth_context auth_context; 805 char phost[BUFSIZ]; 806 const char *services[3], **service; 807 808 packet.data = 0; 809 810 /* If possible we want to try and verify the ticket we have 811 * received against a keytab. We will try multiple service 812 * principals, including at least the host principal and the PAM 813 * service principal. The host principal is preferred because access 814 * to that key is generally sufficient to compromise root, while the 815 * service key for this PAM service may be less carefully guarded. 816 * It is important to check the keytab first before the KDC so we do 817 * not get spoofed by a fake KDC. 818 */ 819 services[0] = "host"; 820 services[1] = pam_service; 821 services[2] = NULL; 822 keyblock = 0; 823 retval = -1; 824 for (service = &services[0]; *service != NULL; service++) { 825 retval = krb5_sname_to_principal(context, NULL, *service, 826 KRB5_NT_SRV_HST, &princ); 827 if (retval != 0) { 828 if (debug) 829 syslog(LOG_DEBUG, 830 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 831 "krb5_sname_to_principal()", 832 krb5_get_err_text(context, retval)); 833 return -1; 834 } 835 836 /* Extract the name directly. */ 837 strncpy(phost, compat_princ_component(context, princ, 1), 838 BUFSIZ); 839 phost[BUFSIZ - 1] = '\0'; 840 841 /* 842 * Do we have service/<host> keys? 843 * (use default/configured keytab, kvno IGNORE_VNO to get the 844 * first match, and ignore enctype.) 845 */ 846 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 847 &keyblock); 848 if (retval != 0) 849 continue; 850 break; 851 } 852 if (retval != 0) { /* failed to find key */ 853 /* Keytab or service key does not exist */ 854 if (debug) 855 syslog(LOG_DEBUG, 856 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 857 "krb5_kt_read_service_key()", 858 krb5_get_err_text(context, retval)); 859 retval = 0; 860 goto cleanup; 861 } 862 if (keyblock) 863 krb5_free_keyblock(context, keyblock); 864 865 /* Talk to the kdc and construct the ticket. */ 866 auth_context = NULL; 867 retval = krb5_mk_req(context, &auth_context, 0, *service, phost, 868 NULL, ccache, &packet); 869 if (auth_context) { 870 krb5_auth_con_free(context, auth_context); 871 auth_context = NULL; /* setup for rd_req */ 872 } 873 if (retval) { 874 if (debug) 875 syslog(LOG_DEBUG, 876 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 877 "krb5_mk_req()", 878 krb5_get_err_text(context, retval)); 879 retval = -1; 880 goto cleanup; 881 } 882 883 /* Try to use the ticket. */ 884 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 885 NULL, NULL); 886 if (retval) { 887 if (debug) 888 syslog(LOG_DEBUG, 889 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 890 "krb5_rd_req()", 891 krb5_get_err_text(context, retval)); 892 retval = -1; 893 } 894 else 895 retval = 1; 896 897cleanup: 898 if (packet.data) 899 compat_free_data_contents(context, &packet); 900 krb5_free_principal(context, princ); 901 return retval; 902} 903 904/* Free the memory for cache_name. Called by pam_end() */ 905/* ARGSUSED */ 906static void 907cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 908{ 909 krb5_context pam_context; 910 krb5_ccache ccache; 911 krb5_error_code krbret; 912 913 if (krb5_init_context(&pam_context)) 914 return; 915 916 krbret = krb5_cc_resolve(pam_context, data, &ccache); 917 if (krbret == 0) 918 krb5_cc_destroy(pam_context, ccache); 919 krb5_free_context(pam_context); 920 free(data); 921} 922 923#ifdef COMPAT_HEIMDAL 924#ifdef COMPAT_MIT 925#error This cannot be MIT and Heimdal compatible! 926#endif 927#endif 928 929#ifndef COMPAT_HEIMDAL 930#ifndef COMPAT_MIT 931#error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 932#endif 933#endif 934 935#ifdef COMPAT_HEIMDAL 936/* ARGSUSED */ 937static const char * 938compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 939{ 940 return princ->name.name_string.val[n]; 941} 942 943/* ARGSUSED */ 944static void 945compat_free_data_contents(krb5_context context __unused, krb5_data * data) 946{ 947 krb5_xfree(data->data); 948} 949#endif 950 951#ifdef COMPAT_MIT 952static const char * 953compat_princ_component(krb5_context context, krb5_principal princ, int n) 954{ 955 return krb5_princ_component(context, princ, n)->data; 956} 957 958static void 959compat_free_data_contents(krb5_context context, krb5_data * data) 960{ 961 krb5_free_data_contents(context, data); 962} 963#endif 964