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("$FreeBSD$"); 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 78 static int verify_krb_v5_tgt(krb5_context, krb5_ccache, char *, int); 79 static void cleanup_cache(pam_handle_t *, void *, int); 80 static const char *compat_princ_component(krb5_context, krb5_principal, int); 81 static 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 87 enum { 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 95 static 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 */ 107 PAM_EXTERN int 108 pam_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"); 328 329 cleanup: 330 krb5_free_cred_contents(pam_context, &creds); 331 PAM_LOG("Done cleanup"); 332 cleanup2: 333 krb5_free_principal(pam_context, princ); 334 PAM_LOG("Done cleanup2"); 335 cleanup3: 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 } 348 349 PAM_EXTERN int 350 pam_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 retval = PAM_CRED_UNAVAIL; 411 goto cleanup3; 412 } 413 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_temp); 414 if (krbret != 0) { 415 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", cache_name, 416 krb5_get_err_text(pam_context, krbret)); 417 retval = PAM_SERVICE_ERR; 418 goto cleanup3; 419 } 420 421 /* Get the uid. This should exist. */ 422 pwd = getpwnam(user); 423 if (pwd == NULL) { 424 retval = PAM_USER_UNKNOWN; 425 goto cleanup3; 426 } 427 428 PAM_LOG("Done getpwnam()"); 429 430 /* Avoid following a symlink as root */ 431 if (setegid(pwd->pw_gid)) { 432 retval = PAM_SERVICE_ERR; 433 goto cleanup3; 434 } 435 if (seteuid(pwd->pw_uid)) { 436 retval = PAM_SERVICE_ERR; 437 goto cleanup3; 438 } 439 440 PAM_LOG("Done setegid() & seteuid()"); 441 442 /* Get the cache name */ 443 cache_name = NULL; 444 pam_test_option(&options, PAM_OPT_CCACHE, &cache_name); 445 if (cache_name == NULL) 446 asprintf(&cache_name, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 447 448 p = calloc(PATH_MAX + 16, sizeof(char)); 449 q = cache_name; 450 451 if (p == NULL) { 452 PAM_LOG("Error malloc(): failure"); 453 retval = PAM_BUF_ERR; 454 goto cleanup3; 455 } 456 cache_name = p; 457 458 /* convert %u and %p */ 459 while (*q) { 460 if (*q == '%') { 461 q++; 462 if (*q == 'u') { 463 sprintf(p, "%d", pwd->pw_uid); 464 p += strlen(p); 465 } 466 else if (*q == 'p') { 467 sprintf(p, "%d", getpid()); 468 p += strlen(p); 469 } 470 else { 471 /* Not a special token */ 472 *p++ = '%'; 473 q--; 474 } 475 q++; 476 } 477 else { 478 *p++ = *q++; 479 } 480 } 481 482 PAM_LOG("Got cache_name: %s", cache_name); 483 484 /* Initialize the new ccache */ 485 krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ); 486 if (krbret != 0) { 487 PAM_LOG("Error krb5_cc_get_principal(): %s", 488 krb5_get_err_text(pam_context, krbret)); 489 retval = PAM_SERVICE_ERR; 490 goto cleanup3; 491 } 492 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm); 493 if (krbret != 0) { 494 PAM_LOG("Error krb5_cc_resolve(): %s", 495 krb5_get_err_text(pam_context, krbret)); 496 retval = PAM_SERVICE_ERR; 497 goto cleanup2; 498 } 499 krbret = krb5_cc_initialize(pam_context, ccache_perm, princ); 500 if (krbret != 0) { 501 PAM_LOG("Error krb5_cc_initialize(): %s", 502 krb5_get_err_text(pam_context, krbret)); 503 retval = PAM_SERVICE_ERR; 504 goto cleanup2; 505 } 506 507 PAM_LOG("Cache initialised"); 508 509 /* Prepare for iteration over creds */ 510 krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor); 511 if (krbret != 0) { 512 PAM_LOG("Error krb5_cc_start_seq_get(): %s", 513 krb5_get_err_text(pam_context, krbret)); 514 krb5_cc_destroy(pam_context, ccache_perm); 515 retval = PAM_SERVICE_ERR; 516 goto cleanup2; 517 } 518 519 PAM_LOG("Prepared for iteration"); 520 521 /* Copy the creds (should be two of them) */ 522 while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp, 523 &cursor, &creds) == 0)) { 524 krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds); 525 if (krbret != 0) { 526 PAM_LOG("Error krb5_cc_store_cred(): %s", 527 krb5_get_err_text(pam_context, krbret)); 528 krb5_cc_destroy(pam_context, ccache_perm); 529 krb5_free_cred_contents(pam_context, &creds); 530 retval = PAM_SERVICE_ERR; 531 goto cleanup2; 532 } 533 krb5_free_cred_contents(pam_context, &creds); 534 PAM_LOG("Iteration"); 535 } 536 krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor); 537 538 PAM_LOG("Done iterating"); 539 540 if (strstr(cache_name, "FILE:") == cache_name) { 541 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 542 PAM_LOG("Error chown(): %s", strerror(errno)); 543 krb5_cc_destroy(pam_context, ccache_perm); 544 retval = PAM_SERVICE_ERR; 545 goto cleanup2; 546 } 547 PAM_LOG("Done chown()"); 548 549 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 550 PAM_LOG("Error chmod(): %s", strerror(errno)); 551 krb5_cc_destroy(pam_context, ccache_perm); 552 retval = PAM_SERVICE_ERR; 553 goto cleanup2; 554 } 555 PAM_LOG("Done chmod()"); 556 } 557 558 krb5_cc_close(pam_context, ccache_perm); 559 560 PAM_LOG("Cache closed"); 561 562 cache_env_name = malloc(strlen(cache_name) + 12); 563 if (!cache_env_name) { 564 PAM_LOG("Error malloc(): failure"); 565 krb5_cc_destroy(pam_context, ccache_perm); 566 retval = PAM_BUF_ERR; 567 goto cleanup2; 568 } 569 570 sprintf(cache_env_name, "KRB5CCNAME=%s", cache_name); 571 if ((retval = pam_putenv(pamh, cache_env_name)) != 0) { 572 PAM_LOG("Error pam_putenv(): %s", pam_strerror(pamh, retval)); 573 krb5_cc_destroy(pam_context, ccache_perm); 574 retval = PAM_SERVICE_ERR; 575 goto cleanup2; 576 } 577 578 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 579 580 cleanup2: 581 krb5_free_principal(pam_context, princ); 582 PAM_LOG("Done cleanup2"); 583 cleanup3: 584 krb5_free_context(pam_context); 585 PAM_LOG("Done cleanup3"); 586 587 seteuid(euid); 588 setegid(egid); 589 590 PAM_LOG("Done seteuid() & setegid()"); 591 592 return (retval); 593 } 594 595 /* 596 * account management 597 */ 598 PAM_EXTERN int 599 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 600 int argc, const char *argv[]) 601 { 602 krb5_error_code krbret; 603 krb5_context pam_context; 604 krb5_ccache ccache; 605 krb5_principal princ; 606 struct options options; 607 int retval; 608 const char *user, *ccache_name; 609 610 pam_std_option(&options, other_options, argc, argv); 611 612 PAM_LOG("Options processed"); 613 614 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 615 if (retval != PAM_SUCCESS) 616 return (retval); 617 618 PAM_LOG("Got user: %s", user); 619 620 retval = pam_get_data(pamh, "ccache", (const void **)&ccache_name); 621 if (retval != PAM_SUCCESS) 622 return (PAM_SUCCESS); 623 624 PAM_LOG("Got credentials"); 625 626 krbret = krb5_init_context(&pam_context); 627 if (krbret != 0) { 628 PAM_LOG("Error krb5_init_context() failed"); 629 return (PAM_PERM_DENIED); 630 } 631 632 PAM_LOG("Context initialised"); 633 634 krbret = krb5_cc_resolve(pam_context, ccache_name, &ccache); 635 if (krbret != 0) { 636 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", ccache_name, 637 krb5_get_err_text(pam_context, krbret)); 638 krb5_free_context(pam_context); 639 return (PAM_PERM_DENIED); 640 } 641 642 PAM_LOG("Got ccache %s", ccache_name); 643 644 645 krbret = krb5_cc_get_principal(pam_context, ccache, &princ); 646 if (krbret != 0) { 647 PAM_LOG("Error krb5_cc_get_principal(): %s", 648 krb5_get_err_text(pam_context, krbret)); 649 retval = PAM_PERM_DENIED;; 650 goto cleanup; 651 } 652 653 PAM_LOG("Got principal"); 654 655 if (krb5_kuserok(pam_context, princ, user)) 656 retval = PAM_SUCCESS; 657 else 658 retval = PAM_PERM_DENIED; 659 krb5_free_principal(pam_context, princ); 660 661 PAM_LOG("Done kuserok()"); 662 663 cleanup: 664 krb5_free_context(pam_context); 665 PAM_LOG("Done cleanup"); 666 667 return (retval); 668 669 } 670 671 /* 672 * password management 673 */ 674 PAM_EXTERN int 675 pam_sm_chauthtok(pam_handle_t *pamh, int flags, 676 int argc, const char *argv[]) 677 { 678 krb5_error_code krbret; 679 krb5_context pam_context; 680 krb5_creds creds; 681 krb5_principal princ; 682 krb5_get_init_creds_opt opts; 683 krb5_data result_code_string, result_string; 684 struct options options; 685 int result_code, retval; 686 const char *user, *pass; 687 char *princ_name, *passdup; 688 689 pam_std_option(&options, other_options, argc, argv); 690 691 PAM_LOG("Options processed"); 692 693 if (!(flags & PAM_UPDATE_AUTHTOK)) 694 return (PAM_AUTHTOK_ERR); 695 696 retval = pam_get_item(pamh, PAM_USER, (const void **)&user); 697 if (retval != PAM_SUCCESS) 698 return (retval); 699 700 PAM_LOG("Got user: %s", user); 701 702 krbret = krb5_init_context(&pam_context); 703 if (krbret != 0) { 704 PAM_LOG("Error krb5_init_context() failed"); 705 return (PAM_SERVICE_ERR); 706 } 707 708 PAM_LOG("Context initialised"); 709 710 krb5_get_init_creds_opt_init(&opts); 711 712 PAM_LOG("Credentials options initialised"); 713 714 /* Get principal name */ 715 krbret = krb5_parse_name(pam_context, user, &princ); 716 if (krbret != 0) { 717 PAM_LOG("Error krb5_parse_name(): %s", 718 krb5_get_err_text(pam_context, krbret)); 719 retval = PAM_USER_UNKNOWN; 720 goto cleanup3; 721 } 722 723 /* Now convert the principal name into something human readable */ 724 princ_name = NULL; 725 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 726 if (krbret != 0) { 727 PAM_LOG("Error krb5_unparse_name(): %s", 728 krb5_get_err_text(pam_context, krbret)); 729 retval = PAM_SERVICE_ERR; 730 goto cleanup2; 731 } 732 733 PAM_LOG("Got principal: %s", princ_name); 734 735 /* Get password */ 736 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT); 737 if (retval != PAM_SUCCESS) 738 goto cleanup2; 739 740 PAM_LOG("Got password"); 741 742 memset(&creds, 0, sizeof(krb5_creds)); 743 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 744 pass, NULL, pamh, 0, "kadmin/changepw", &opts); 745 if (krbret != 0) { 746 PAM_LOG("Error krb5_get_init_creds_password()", 747 krb5_get_err_text(pam_context, krbret)); 748 retval = PAM_AUTH_ERR; 749 goto cleanup2; 750 } 751 752 PAM_LOG("Credentials established"); 753 754 /* Now get the new password */ 755 for (;;) { 756 retval = pam_get_authtok(pamh, 757 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 758 if (retval != PAM_TRY_AGAIN) 759 break; 760 pam_error(pamh, "Mismatch; try again, EOF to quit."); 761 } 762 if (retval != PAM_SUCCESS) 763 goto cleanup; 764 765 PAM_LOG("Got new password"); 766 767 /* Change it */ 768 if ((passdup = strdup(pass)) == NULL) { 769 retval = PAM_BUF_ERR; 770 goto cleanup; 771 } 772 krbret = krb5_change_password(pam_context, &creds, passdup, 773 &result_code, &result_code_string, &result_string); 774 free(passdup); 775 if (krbret != 0) { 776 PAM_LOG("Error krb5_change_password(): %s", 777 krb5_get_err_text(pam_context, krbret)); 778 retval = PAM_AUTHTOK_ERR; 779 goto cleanup; 780 } 781 if (result_code) { 782 PAM_LOG("Error krb5_change_password(): (result_code)"); 783 retval = PAM_AUTHTOK_ERR; 784 goto cleanup; 785 } 786 787 PAM_LOG("Password changed"); 788 789 if (result_string.data) 790 free(result_string.data); 791 if (result_code_string.data) 792 free(result_code_string.data); 793 794 cleanup: 795 krb5_free_cred_contents(pam_context, &creds); 796 PAM_LOG("Done cleanup"); 797 cleanup2: 798 krb5_free_principal(pam_context, princ); 799 PAM_LOG("Done cleanup2"); 800 cleanup3: 801 if (princ_name) 802 free(princ_name); 803 804 krb5_free_context(pam_context); 805 806 PAM_LOG("Done cleanup3"); 807 808 return (retval); 809 } 810 811 PAM_MODULE_ENTRY("pam_krb5"); 812 813 /* 814 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 815 * Modified by Sam Hartman <hartmans@mit.edu> to support PAM services 816 * for Debian. 817 * 818 * Verify the Kerberos ticket-granting ticket just retrieved for the 819 * user. If the Kerberos server doesn't respond, assume the user is 820 * trying to fake us out (since we DID just get a TGT from what is 821 * supposedly our KDC). If the host/<host> service is unknown (i.e., 822 * the local keytab doesn't have it), and we cannot find another 823 * service we do have, let her in. 824 * 825 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 826 */ 827 static int 828 verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 829 char *pam_service, int debug) 830 { 831 krb5_error_code retval; 832 krb5_principal princ; 833 krb5_keyblock *keyblock; 834 krb5_data packet; 835 krb5_auth_context auth_context; 836 char phost[BUFSIZ]; 837 const char *services[3], **service; 838 839 packet.data = 0; 840 841 /* If possible we want to try and verify the ticket we have 842 * received against a keytab. We will try multiple service 843 * principals, including at least the host principal and the PAM 844 * service principal. The host principal is preferred because access 845 * to that key is generally sufficient to compromise root, while the 846 * service key for this PAM service may be less carefully guarded. 847 * It is important to check the keytab first before the KDC so we do 848 * not get spoofed by a fake KDC. 849 */ 850 services[0] = "host"; 851 services[1] = pam_service; 852 services[2] = NULL; 853 keyblock = 0; 854 retval = -1; 855 for (service = &services[0]; *service != NULL; service++) { 856 retval = krb5_sname_to_principal(context, NULL, *service, 857 KRB5_NT_SRV_HST, &princ); 858 if (retval != 0) { 859 if (debug) 860 syslog(LOG_DEBUG, 861 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 862 "krb5_sname_to_principal()", 863 krb5_get_err_text(context, retval)); 864 return -1; 865 } 866 867 /* Extract the name directly. */ 868 strncpy(phost, compat_princ_component(context, princ, 1), 869 BUFSIZ); 870 phost[BUFSIZ - 1] = '\0'; 871 872 /* 873 * Do we have service/<host> keys? 874 * (use default/configured keytab, kvno IGNORE_VNO to get the 875 * first match, and ignore enctype.) 876 */ 877 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 878 &keyblock); 879 if (retval != 0) 880 continue; 881 break; 882 } 883 if (retval != 0) { /* failed to find key */ 884 /* Keytab or service key does not exist */ 885 if (debug) 886 syslog(LOG_DEBUG, 887 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 888 "krb5_kt_read_service_key()", 889 krb5_get_err_text(context, retval)); 890 retval = 0; 891 goto cleanup; 892 } 893 if (keyblock) 894 krb5_free_keyblock(context, keyblock); 895 896 /* Talk to the kdc and construct the ticket. */ 897 auth_context = NULL; 898 retval = krb5_mk_req(context, &auth_context, 0, *service, phost, 899 NULL, ccache, &packet); 900 if (auth_context) { 901 krb5_auth_con_free(context, auth_context); 902 auth_context = NULL; /* setup for rd_req */ 903 } 904 if (retval) { 905 if (debug) 906 syslog(LOG_DEBUG, 907 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 908 "krb5_mk_req()", 909 krb5_get_err_text(context, retval)); 910 retval = -1; 911 goto cleanup; 912 } 913 914 /* Try to use the ticket. */ 915 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 916 NULL, NULL); 917 if (retval) { 918 if (debug) 919 syslog(LOG_DEBUG, 920 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 921 "krb5_rd_req()", 922 krb5_get_err_text(context, retval)); 923 retval = -1; 924 } 925 else 926 retval = 1; 927 928 cleanup: 929 if (packet.data) 930 compat_free_data_contents(context, &packet); 931 krb5_free_principal(context, princ); 932 return retval; 933 } 934 935 /* Free the memory for cache_name. Called by pam_end() */ 936 static void 937 cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 938 { 939 krb5_context pam_context; 940 krb5_ccache ccache; 941 krb5_error_code krbret; 942 943 if (krb5_init_context(&pam_context)) 944 return; 945 946 krbret = krb5_cc_resolve(pam_context, data, &ccache); 947 if (krbret == 0) 948 krb5_cc_destroy(pam_context, ccache); 949 krb5_free_context(pam_context); 950 free(data); 951 } 952 953 #ifdef COMPAT_HEIMDAL 954 #ifdef COMPAT_MIT 955 #error This cannot be MIT and Heimdal compatible! 956 #endif 957 #endif 958 959 #ifndef COMPAT_HEIMDAL 960 #ifndef COMPAT_MIT 961 #error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 962 #endif 963 #endif 964 965 #ifdef COMPAT_HEIMDAL 966 static const char * 967 compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 968 { 969 return princ->name.name_string.val[n]; 970 } 971 972 static void 973 compat_free_data_contents(krb5_context context __unused, krb5_data * data) 974 { 975 krb5_xfree(data->data); 976 } 977 #endif 978 979 #ifdef COMPAT_MIT 980 static const char * 981 compat_princ_component(krb5_context context, krb5_principal princ, int n) 982 { 983 return krb5_princ_component(context, princ, n)->data; 984 } 985 986 static void 987 compat_free_data_contents(krb5_context context, krb5_data * data) 988 { 989 krb5_free_data_contents(context, data); 990 } 991 #endif 992