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/types.h> 51 #include <sys/stat.h> 52 #include <errno.h> 53 #include <limits.h> 54 #include <pwd.h> 55 #include <stdio.h> 56 #include <stdlib.h> 57 #include <string.h> 58 #include <syslog.h> 59 #include <unistd.h> 60 61 #include <krb5.h> 62 #include <com_err.h> 63 64 #define PAM_SM_AUTH 65 #define PAM_SM_ACCOUNT 66 #define PAM_SM_PASSWORD 67 68 #include <security/pam_appl.h> 69 #include <security/pam_modules.h> 70 #include <security/pam_mod_misc.h> 71 #include <security/openpam.h> 72 73 #define COMPAT_HEIMDAL 74 /* #define COMPAT_MIT */ 75 76 static int verify_krb_v5_tgt_begin(krb5_context, char *, int, 77 const char **, krb5_principal *, char[static BUFSIZ]); 78 static int verify_krb_v5_tgt(krb5_context, krb5_ccache, char *, int, 79 const char *, krb5_principal, char[static BUFSIZ]); 80 static void verify_krb_v5_tgt_cleanup(krb5_context, int, 81 const char *, krb5_principal, char[static BUFSIZ]); 82 static void cleanup_cache(pam_handle_t *, void *, int); 83 static const char *compat_princ_component(krb5_context, krb5_principal, int); 84 static void compat_free_data_contents(krb5_context, krb5_data *); 85 86 #define USER_PROMPT "Username: " 87 #define PASSWORD_PROMPT "Password:" 88 #define NEW_PASSWORD_PROMPT "New Password:" 89 90 #define PAM_OPT_CCACHE "ccache" 91 #define PAM_OPT_DEBUG "debug" 92 #define PAM_OPT_FORWARDABLE "forwardable" 93 #define PAM_OPT_NO_CCACHE "no_ccache" 94 #define PAM_OPT_NO_USER_CHECK "no_user_check" 95 #define PAM_OPT_REUSE_CCACHE "reuse_ccache" 96 #define PAM_OPT_NO_USER_CHECK "no_user_check" 97 #define PAM_OPT_ALLOW_KDC_SPOOF "allow_kdc_spoof" 98 99 #define PAM_LOG_KRB5_ERR(ctx, rv, fmt, ...) \ 100 do { \ 101 const char *krb5msg = krb5_get_error_message(ctx, rv); \ 102 PAM_LOG(fmt ": %s", ##__VA_ARGS__, krb5msg); \ 103 krb5_free_error_message(ctx, krb5msg); \ 104 } while (0) 105 106 /* 107 * authentication management 108 */ 109 PAM_EXTERN int 110 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 111 int argc __unused, const char *argv[] __unused) 112 { 113 krb5_error_code krbret; 114 krb5_context krbctx; 115 int debug; 116 const char *auth_service; 117 krb5_principal auth_princ; 118 char auth_phost[BUFSIZ]; 119 krb5_creds creds; 120 krb5_principal princ; 121 krb5_ccache ccache; 122 krb5_get_init_creds_opt *opts; 123 struct passwd *pwd; 124 int retval; 125 const void *ccache_data; 126 const char *user, *pass; 127 const void *sourceuser, *service; 128 char *principal, *princ_name, *ccache_name, luser[32], *srvdup; 129 130 retval = pam_get_user(pamh, &user, USER_PROMPT); 131 if (retval != PAM_SUCCESS) 132 return (retval); 133 134 PAM_LOG("Got user: %s", user); 135 136 retval = pam_get_item(pamh, PAM_RUSER, &sourceuser); 137 if (retval != PAM_SUCCESS) 138 return (retval); 139 140 PAM_LOG("Got ruser: %s", (const char *)sourceuser); 141 142 service = NULL; 143 pam_get_item(pamh, PAM_SERVICE, &service); 144 if (service == NULL) 145 service = "unknown"; 146 147 PAM_LOG("Got service: %s", (const char *)service); 148 149 if ((srvdup = strdup(service)) == NULL) { 150 retval = PAM_BUF_ERR; 151 goto cleanup6; 152 } 153 154 krbret = krb5_init_context(&krbctx); 155 if (krbret != 0) { 156 PAM_VERBOSE_ERROR("Kerberos 5 error"); 157 retval = PAM_SERVICE_ERR; 158 goto cleanup5; 159 } 160 161 PAM_LOG("Context initialised"); 162 163 debug = openpam_get_option(pamh, PAM_OPT_DEBUG) ? 1 : 0; 164 krbret = verify_krb_v5_tgt_begin(krbctx, srvdup, debug, 165 &auth_service, &auth_princ, auth_phost); 166 if (krbret != 0) { /* failed to find key */ 167 /* Keytab or service key does not exist */ 168 /* 169 * Give up now because we can't authenticate the KDC 170 * with a keytab, unless the administrator asked to 171 * have the traditional behaviour of being vulnerable 172 * to spoofed KDCs. 173 */ 174 if (!openpam_get_option(pamh, PAM_OPT_ALLOW_KDC_SPOOF)) { 175 retval = PAM_SERVICE_ERR; 176 goto cleanup4; 177 } 178 } 179 180 krbret = krb5_cc_register(krbctx, &krb5_mcc_ops, FALSE); 181 if (krbret != 0 && krbret != KRB5_CC_TYPE_EXISTS) { 182 PAM_VERBOSE_ERROR("Kerberos 5 error"); 183 retval = PAM_SERVICE_ERR; 184 goto cleanup3; 185 } 186 187 PAM_LOG("Done krb5_cc_register()"); 188 189 /* Get principal name */ 190 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) 191 asprintf(&principal, "%s/%s", (const char *)sourceuser, user); 192 else 193 principal = strdup(user); 194 195 PAM_LOG("Created principal: %s", principal); 196 197 krbret = krb5_parse_name(krbctx, principal, &princ); 198 free(principal); 199 if (krbret != 0) { 200 PAM_LOG_KRB5_ERR(krbctx, krbret, "Error krb5_parse_name()"); 201 PAM_VERBOSE_ERROR("Kerberos 5 error"); 202 retval = PAM_SERVICE_ERR; 203 goto cleanup3; 204 } 205 206 PAM_LOG("Done krb5_parse_name()"); 207 208 /* Now convert the principal name into something human readable */ 209 princ_name = NULL; 210 krbret = krb5_unparse_name(krbctx, princ, &princ_name); 211 if (krbret != 0) { 212 PAM_LOG_KRB5_ERR(krbctx, krbret, 213 "Error krb5_unparse_name()"); 214 PAM_VERBOSE_ERROR("Kerberos 5 error"); 215 retval = PAM_SERVICE_ERR; 216 goto cleanup2; 217 } 218 219 PAM_LOG("Got principal: %s", princ_name); 220 221 /* Get password */ 222 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, PASSWORD_PROMPT); 223 if (retval != PAM_SUCCESS) 224 goto cleanup2; 225 226 PAM_LOG("Got password"); 227 228 if (openpam_get_option(pamh, PAM_OPT_NO_USER_CHECK)) 229 PAM_LOG("Skipping local user check"); 230 else { 231 232 /* Verify the local user exists (AFTER getting the password) */ 233 if (strchr(user, '@')) { 234 /* get a local account name for this principal */ 235 krbret = krb5_aname_to_localname(krbctx, princ, 236 sizeof(luser), luser); 237 if (krbret != 0) { 238 PAM_VERBOSE_ERROR("Kerberos 5 error"); 239 PAM_LOG_KRB5_ERR(krbctx, krbret, 240 "Error krb5_aname_to_localname()"); 241 retval = PAM_USER_UNKNOWN; 242 goto cleanup2; 243 } 244 245 retval = pam_set_item(pamh, PAM_USER, luser); 246 if (retval != PAM_SUCCESS) 247 goto cleanup2; 248 249 PAM_LOG("PAM_USER Redone"); 250 } 251 252 if (!openpam_get_option(pamh, PAM_OPT_NO_USER_CHECK)) { 253 pwd = getpwnam(user); 254 if (pwd == NULL) { 255 retval = PAM_USER_UNKNOWN; 256 goto cleanup2; 257 } 258 } 259 260 PAM_LOG("Done getpwnam()"); 261 } 262 263 /* Initialize credentials request options. */ 264 krbret = krb5_get_init_creds_opt_alloc(krbctx, &opts); 265 if (krbret != 0) { 266 PAM_LOG_KRB5_ERR(krbctx, krbret, 267 "Error krb5_get_init_creds_opt_alloc()"); 268 PAM_VERBOSE_ERROR("Kerberos 5 error"); 269 retval = PAM_SERVICE_ERR; 270 goto cleanup2; 271 } 272 krb5_get_init_creds_opt_set_default_flags(krbctx, 273 service, NULL, opts); 274 275 if (openpam_get_option(pamh, PAM_OPT_FORWARDABLE)) 276 krb5_get_init_creds_opt_set_forwardable(opts, 1); 277 278 PAM_LOG("Credential options initialised"); 279 280 /* Get a TGT */ 281 memset(&creds, 0, sizeof(krb5_creds)); 282 krbret = krb5_get_init_creds_password(krbctx, &creds, princ, 283 pass, NULL, pamh, 0, NULL, opts); 284 krb5_get_init_creds_opt_free(krbctx, opts); 285 if (krbret != 0) { 286 PAM_VERBOSE_ERROR("Kerberos 5 error"); 287 PAM_LOG_KRB5_ERR(krbctx, krbret, 288 "Error krb5_get_init_creds_password()"); 289 retval = PAM_AUTH_ERR; 290 goto cleanup2; 291 } 292 293 PAM_LOG("Got TGT"); 294 295 /* Generate a temporary cache */ 296 krbret = krb5_cc_new_unique(krbctx, krb5_cc_type_memory, NULL, &ccache); 297 if (krbret != 0) { 298 PAM_VERBOSE_ERROR("Kerberos 5 error"); 299 PAM_LOG_KRB5_ERR(krbctx, krbret, 300 "Error krb5_cc_new_unique()"); 301 retval = PAM_SERVICE_ERR; 302 goto cleanup; 303 } 304 krbret = krb5_cc_initialize(krbctx, ccache, princ); 305 if (krbret != 0) { 306 PAM_VERBOSE_ERROR("Kerberos 5 error"); 307 PAM_LOG_KRB5_ERR(krbctx, krbret, 308 "Error krb5_cc_initialize()"); 309 retval = PAM_SERVICE_ERR; 310 goto cleanup; 311 } 312 krbret = krb5_cc_store_cred(krbctx, ccache, &creds); 313 if (krbret != 0) { 314 PAM_VERBOSE_ERROR("Kerberos 5 error"); 315 PAM_LOG_KRB5_ERR(krbctx, krbret, 316 "Error krb5_cc_store_cred()"); 317 krb5_cc_destroy(krbctx, ccache); 318 retval = PAM_SERVICE_ERR; 319 goto cleanup; 320 } 321 322 PAM_LOG("Credentials stashed"); 323 324 /* Verify them */ 325 krbret = verify_krb_v5_tgt(krbctx, ccache, srvdup, 326 debug, 327 auth_service, auth_princ, auth_phost); 328 free(srvdup); 329 srvdup = NULL; 330 if (krbret == -1) { 331 PAM_VERBOSE_ERROR("Kerberos 5 error"); 332 krb5_cc_destroy(krbctx, ccache); 333 retval = PAM_AUTH_ERR; 334 goto cleanup; 335 } 336 337 PAM_LOG("Credentials stash verified"); 338 339 retval = pam_get_data(pamh, "ccache", &ccache_data); 340 if (retval == PAM_SUCCESS) { 341 krb5_cc_destroy(krbctx, ccache); 342 PAM_VERBOSE_ERROR("Kerberos 5 error"); 343 retval = PAM_AUTH_ERR; 344 goto cleanup; 345 } 346 347 PAM_LOG("Credentials stash not pre-existing"); 348 349 asprintf(&ccache_name, "%s:%s", krb5_cc_get_type(krbctx, 350 ccache), krb5_cc_get_name(krbctx, ccache)); 351 if (ccache_name == NULL) { 352 PAM_VERBOSE_ERROR("Kerberos 5 error"); 353 retval = PAM_BUF_ERR; 354 goto cleanup; 355 } 356 retval = pam_set_data(pamh, "ccache", ccache_name, cleanup_cache); 357 if (retval != 0) { 358 krb5_cc_destroy(krbctx, ccache); 359 PAM_VERBOSE_ERROR("Kerberos 5 error"); 360 retval = PAM_SERVICE_ERR; 361 goto cleanup; 362 } 363 364 PAM_LOG("Credentials stash saved"); 365 366 cleanup: 367 krb5_free_cred_contents(krbctx, &creds); 368 PAM_LOG("Done cleanup"); 369 cleanup2: 370 krb5_free_principal(krbctx, princ); 371 if (princ_name) 372 free(princ_name); 373 PAM_LOG("Done cleanup2"); 374 375 cleanup3: 376 krb5_free_context(krbctx); 377 378 PAM_LOG("Done cleanup3"); 379 380 cleanup4: 381 verify_krb_v5_tgt_cleanup(krbctx, debug, 382 auth_service, auth_princ, auth_phost); 383 PAM_LOG("Done cleanup4"); 384 385 cleanup5: 386 if (srvdup != NULL) 387 free(srvdup); 388 PAM_LOG("Done cleanup5"); 389 390 cleanup6: 391 if (retval != PAM_SUCCESS) 392 PAM_VERBOSE_ERROR("Kerberos 5 refuses you"); 393 PAM_LOG("Done cleanup6"); 394 395 return (retval); 396 } 397 398 PAM_EXTERN int 399 pam_sm_setcred(pam_handle_t *pamh, int flags, 400 int argc __unused, const char *argv[] __unused) 401 { 402 #ifdef _FREEFALL_CONFIG 403 return (PAM_SUCCESS); 404 #else 405 406 krb5_error_code krbret; 407 krb5_context krbctx; 408 krb5_principal princ; 409 krb5_creds creds; 410 krb5_ccache ccache_temp, ccache_perm; 411 krb5_cc_cursor cursor; 412 struct passwd *pwd = NULL; 413 int retval; 414 const char *cache_name, *q; 415 const void *user; 416 const void *cache_data; 417 char *cache_name_buf = NULL, *p; 418 419 uid_t euid; 420 gid_t egid; 421 422 if (flags & PAM_DELETE_CRED) 423 return (PAM_SUCCESS); 424 425 if (flags & PAM_REFRESH_CRED) 426 return (PAM_SUCCESS); 427 428 if (flags & PAM_REINITIALIZE_CRED) 429 return (PAM_SUCCESS); 430 431 if (!(flags & PAM_ESTABLISH_CRED)) 432 return (PAM_SERVICE_ERR); 433 434 /* If a persistent cache isn't desired, stop now. */ 435 if (openpam_get_option(pamh, PAM_OPT_NO_CCACHE) || 436 openpam_get_option(pamh, PAM_OPT_NO_USER_CHECK)) 437 return (PAM_SUCCESS); 438 439 PAM_LOG("Establishing credentials"); 440 441 /* Get username */ 442 retval = pam_get_item(pamh, PAM_USER, &user); 443 if (retval != PAM_SUCCESS) 444 return (retval); 445 446 PAM_LOG("Got user: %s", (const char *)user); 447 448 krbret = krb5_init_context(&krbctx); 449 if (krbret != 0) { 450 PAM_LOG("Error krb5_init_context() failed"); 451 return (PAM_SERVICE_ERR); 452 } 453 454 PAM_LOG("Context initialised"); 455 456 euid = geteuid(); /* Usually 0 */ 457 egid = getegid(); 458 459 PAM_LOG("Got euid, egid: %d %d", euid, egid); 460 461 /* Retrieve the temporary cache */ 462 retval = pam_get_data(pamh, "ccache", &cache_data); 463 if (retval != PAM_SUCCESS) { 464 retval = PAM_CRED_UNAVAIL; 465 goto cleanup3; 466 } 467 krbret = krb5_cc_resolve(krbctx, cache_data, &ccache_temp); 468 if (krbret != 0) { 469 PAM_LOG_KRB5_ERR(krbctx, krbret, 470 "Error krb5_cc_resolve(\"%s\")", (const char *)cache_data); 471 retval = PAM_SERVICE_ERR; 472 goto cleanup3; 473 } 474 475 /* Get the uid. This should exist. */ 476 pwd = getpwnam(user); 477 if (pwd == NULL) { 478 retval = PAM_USER_UNKNOWN; 479 goto cleanup3; 480 } 481 482 PAM_LOG("Done getpwnam()"); 483 484 /* Avoid following a symlink as root */ 485 if (setegid(pwd->pw_gid)) { 486 retval = PAM_SERVICE_ERR; 487 goto cleanup3; 488 } 489 if (seteuid(pwd->pw_uid)) { 490 retval = PAM_SERVICE_ERR; 491 goto cleanup3; 492 } 493 494 PAM_LOG("Done setegid() & seteuid()"); 495 496 /* Get the cache name */ 497 cache_name = openpam_get_option(pamh, PAM_OPT_CCACHE); 498 if (cache_name == NULL) { 499 asprintf(&cache_name_buf, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 500 cache_name = cache_name_buf; 501 } 502 503 p = calloc(PATH_MAX + 16, sizeof(char)); 504 q = cache_name; 505 506 if (p == NULL) { 507 PAM_LOG("Error malloc(): failure"); 508 retval = PAM_BUF_ERR; 509 goto cleanup3; 510 } 511 cache_name = p; 512 513 /* convert %u and %p */ 514 while (*q) { 515 if (*q == '%') { 516 q++; 517 if (*q == 'u') { 518 sprintf(p, "%d", pwd->pw_uid); 519 p += strlen(p); 520 } 521 else if (*q == 'p') { 522 sprintf(p, "%d", getpid()); 523 p += strlen(p); 524 } 525 else { 526 /* Not a special token */ 527 *p++ = '%'; 528 q--; 529 } 530 q++; 531 } 532 else { 533 *p++ = *q++; 534 } 535 } 536 537 PAM_LOG("Got cache_name: %s", cache_name); 538 539 /* Initialize the new ccache */ 540 krbret = krb5_cc_get_principal(krbctx, ccache_temp, &princ); 541 if (krbret != 0) { 542 PAM_LOG_KRB5_ERR(krbctx, krbret, 543 "Error krb5_cc_get_principal()"); 544 retval = PAM_SERVICE_ERR; 545 goto cleanup3; 546 } 547 krbret = krb5_cc_resolve(krbctx, cache_name, &ccache_perm); 548 if (krbret != 0) { 549 PAM_LOG_KRB5_ERR(krbctx, krbret, "Error krb5_cc_resolve()"); 550 retval = PAM_SERVICE_ERR; 551 goto cleanup2; 552 } 553 krbret = krb5_cc_initialize(krbctx, ccache_perm, princ); 554 if (krbret != 0) { 555 PAM_LOG_KRB5_ERR(krbctx, krbret, 556 "Error krb5_cc_initialize()"); 557 retval = PAM_SERVICE_ERR; 558 goto cleanup2; 559 } 560 561 PAM_LOG("Cache initialised"); 562 563 /* Prepare for iteration over creds */ 564 krbret = krb5_cc_start_seq_get(krbctx, ccache_temp, &cursor); 565 if (krbret != 0) { 566 PAM_LOG_KRB5_ERR(krbctx, krbret, 567 "Error krb5_cc_start_seq_get()"); 568 krb5_cc_destroy(krbctx, ccache_perm); 569 retval = PAM_SERVICE_ERR; 570 goto cleanup2; 571 } 572 573 PAM_LOG("Prepared for iteration"); 574 575 /* Copy the creds (should be two of them) */ 576 while (krb5_cc_next_cred(krbctx, ccache_temp, &cursor, &creds) == 0) { 577 krbret = krb5_cc_store_cred(krbctx, ccache_perm, &creds); 578 if (krbret != 0) { 579 PAM_LOG_KRB5_ERR(krbctx, krbret, 580 "Error krb5_cc_store_cred()"); 581 krb5_cc_destroy(krbctx, ccache_perm); 582 krb5_free_cred_contents(krbctx, &creds); 583 retval = PAM_SERVICE_ERR; 584 goto cleanup2; 585 } 586 krb5_free_cred_contents(krbctx, &creds); 587 PAM_LOG("Iteration"); 588 } 589 krb5_cc_end_seq_get(krbctx, ccache_temp, &cursor); 590 591 PAM_LOG("Done iterating"); 592 593 if (strstr(cache_name, "FILE:") == cache_name) { 594 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 595 PAM_LOG("Error chown(): %s", strerror(errno)); 596 krb5_cc_destroy(krbctx, ccache_perm); 597 retval = PAM_SERVICE_ERR; 598 goto cleanup2; 599 } 600 PAM_LOG("Done chown()"); 601 602 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 603 PAM_LOG("Error chmod(): %s", strerror(errno)); 604 krb5_cc_destroy(krbctx, ccache_perm); 605 retval = PAM_SERVICE_ERR; 606 goto cleanup2; 607 } 608 PAM_LOG("Done chmod()"); 609 } 610 611 krb5_cc_close(krbctx, ccache_perm); 612 613 PAM_LOG("Cache closed"); 614 615 retval = pam_setenv(pamh, "KRB5CCNAME", cache_name, 1); 616 if (retval != PAM_SUCCESS) { 617 PAM_LOG("Error pam_setenv(): %s", pam_strerror(pamh, retval)); 618 krb5_cc_destroy(krbctx, ccache_perm); 619 retval = PAM_SERVICE_ERR; 620 goto cleanup2; 621 } 622 623 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 624 625 cleanup2: 626 krb5_free_principal(krbctx, princ); 627 PAM_LOG("Done cleanup2"); 628 cleanup3: 629 krb5_free_context(krbctx); 630 PAM_LOG("Done cleanup3"); 631 632 seteuid(euid); 633 setegid(egid); 634 635 PAM_LOG("Done seteuid() & setegid()"); 636 637 if (cache_name_buf != NULL) 638 free(cache_name_buf); 639 640 return (retval); 641 #endif 642 } 643 644 /* 645 * account management 646 */ 647 PAM_EXTERN int 648 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 649 int argc __unused, const char *argv[] __unused) 650 { 651 krb5_error_code krbret; 652 krb5_context krbctx; 653 krb5_ccache ccache; 654 krb5_principal princ; 655 int retval; 656 const void *user; 657 const void *ccache_name; 658 659 retval = pam_get_item(pamh, PAM_USER, &user); 660 if (retval != PAM_SUCCESS) 661 return (retval); 662 663 PAM_LOG("Got user: %s", (const char *)user); 664 665 retval = pam_get_data(pamh, "ccache", &ccache_name); 666 if (retval != PAM_SUCCESS) 667 return (PAM_SUCCESS); 668 669 PAM_LOG("Got credentials"); 670 671 krbret = krb5_init_context(&krbctx); 672 if (krbret != 0) { 673 PAM_LOG("Error krb5_init_context() failed"); 674 return (PAM_PERM_DENIED); 675 } 676 677 PAM_LOG("Context initialised"); 678 679 krbret = krb5_cc_resolve(krbctx, (const char *)ccache_name, &ccache); 680 if (krbret != 0) { 681 PAM_LOG_KRB5_ERR(krbctx, krbret, 682 "Error krb5_cc_resolve(\"%s\")", (const char *)ccache_name); 683 krb5_free_context(krbctx); 684 return (PAM_PERM_DENIED); 685 } 686 687 PAM_LOG("Got ccache %s", (const char *)ccache_name); 688 689 690 krbret = krb5_cc_get_principal(krbctx, ccache, &princ); 691 if (krbret != 0) { 692 PAM_LOG_KRB5_ERR(krbctx, krbret, 693 "Error krb5_cc_get_principal()"); 694 retval = PAM_PERM_DENIED; 695 goto cleanup; 696 } 697 698 PAM_LOG("Got principal"); 699 700 if (krb5_kuserok(krbctx, princ, (const char *)user)) 701 retval = PAM_SUCCESS; 702 else 703 retval = PAM_PERM_DENIED; 704 krb5_free_principal(krbctx, princ); 705 706 PAM_LOG("Done kuserok()"); 707 708 cleanup: 709 krb5_free_context(krbctx); 710 PAM_LOG("Done cleanup"); 711 712 return (retval); 713 714 } 715 716 /* 717 * password management 718 */ 719 PAM_EXTERN int 720 pam_sm_chauthtok(pam_handle_t *pamh, int flags, 721 int argc __unused, const char *argv[] __unused) 722 { 723 krb5_error_code krbret; 724 krb5_context krbctx; 725 krb5_creds creds; 726 krb5_principal princ; 727 krb5_get_init_creds_opt *opts; 728 krb5_data result_code_string, result_string; 729 int result_code, retval; 730 const char *pass; 731 const void *user; 732 char *princ_name, *passdup; 733 734 if (!(flags & PAM_UPDATE_AUTHTOK)) 735 return (PAM_AUTHTOK_ERR); 736 737 retval = pam_get_item(pamh, PAM_USER, &user); 738 if (retval != PAM_SUCCESS) 739 return (retval); 740 741 PAM_LOG("Got user: %s", (const char *)user); 742 743 krbret = krb5_init_context(&krbctx); 744 if (krbret != 0) { 745 PAM_LOG("Error krb5_init_context() failed"); 746 return (PAM_SERVICE_ERR); 747 } 748 749 PAM_LOG("Context initialised"); 750 751 /* Get principal name */ 752 krbret = krb5_parse_name(krbctx, (const char *)user, &princ); 753 if (krbret != 0) { 754 PAM_LOG_KRB5_ERR(krbctx, krbret, 755 "Error krb5_parse_name()"); 756 retval = PAM_USER_UNKNOWN; 757 goto cleanup3; 758 } 759 760 /* Now convert the principal name into something human readable */ 761 princ_name = NULL; 762 krbret = krb5_unparse_name(krbctx, princ, &princ_name); 763 if (krbret != 0) { 764 PAM_LOG_KRB5_ERR(krbctx, krbret, 765 "Error krb5_unparse_name()"); 766 retval = PAM_SERVICE_ERR; 767 goto cleanup2; 768 } 769 770 PAM_LOG("Got principal: %s", princ_name); 771 772 /* Get password */ 773 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, PASSWORD_PROMPT); 774 if (retval != PAM_SUCCESS) 775 goto cleanup2; 776 777 PAM_LOG("Got password"); 778 779 /* Initialize credentials request options. */ 780 krbret = krb5_get_init_creds_opt_alloc(krbctx, &opts); 781 if (krbret != 0) { 782 PAM_LOG_KRB5_ERR(krbctx, krbret, 783 "Error krb5_get_init_creds_opt_alloc()"); 784 PAM_VERBOSE_ERROR("Kerberos 5 error"); 785 retval = PAM_SERVICE_ERR; 786 goto cleanup2; 787 } 788 789 PAM_LOG("Credentials options initialised"); 790 791 memset(&creds, 0, sizeof(krb5_creds)); 792 krbret = krb5_get_init_creds_password(krbctx, &creds, princ, 793 pass, NULL, pamh, 0, "kadmin/changepw", opts); 794 krb5_get_init_creds_opt_free(krbctx, opts); 795 if (krbret != 0) { 796 PAM_LOG_KRB5_ERR(krbctx, krbret, 797 "Error krb5_get_init_creds_password()"); 798 retval = PAM_AUTH_ERR; 799 goto cleanup2; 800 } 801 802 PAM_LOG("Credentials established"); 803 804 /* Now get the new password */ 805 for (;;) { 806 retval = pam_get_authtok(pamh, 807 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 808 if (retval != PAM_TRY_AGAIN) 809 break; 810 pam_error(pamh, "Mismatch; try again, EOF to quit."); 811 } 812 if (retval != PAM_SUCCESS) 813 goto cleanup; 814 815 PAM_LOG("Got new password"); 816 817 /* Change it */ 818 if ((passdup = strdup(pass)) == NULL) { 819 retval = PAM_BUF_ERR; 820 goto cleanup; 821 } 822 krbret = krb5_set_password(krbctx, &creds, passdup, NULL, 823 &result_code, &result_code_string, &result_string); 824 free(passdup); 825 if (krbret != 0) { 826 PAM_LOG_KRB5_ERR(krbctx, krbret, 827 "Error krb5_change_password()"); 828 retval = PAM_AUTHTOK_ERR; 829 goto cleanup; 830 } 831 if (result_code) { 832 PAM_LOG("Error krb5_change_password(): (result_code)"); 833 retval = PAM_AUTHTOK_ERR; 834 goto cleanup; 835 } 836 837 PAM_LOG("Password changed"); 838 839 if (result_string.data) 840 free(result_string.data); 841 if (result_code_string.data) 842 free(result_code_string.data); 843 844 cleanup: 845 krb5_free_cred_contents(krbctx, &creds); 846 PAM_LOG("Done cleanup"); 847 cleanup2: 848 krb5_free_principal(krbctx, princ); 849 if (princ_name) 850 free(princ_name); 851 PAM_LOG("Done cleanup2"); 852 853 cleanup3: 854 krb5_free_context(krbctx); 855 856 PAM_LOG("Done cleanup3"); 857 858 return (retval); 859 } 860 861 PAM_MODULE_ENTRY("pam_krb5"); 862 863 /* 864 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 865 * Modified by Sam Hartman <hartmans@mit.edu> to support PAM services 866 * for Debian. 867 * 868 * Verify the Kerberos ticket-granting ticket just retrieved for the 869 * user. If the Kerberos server doesn't respond, assume the user is 870 * trying to fake us out (since we DID just get a TGT from what is 871 * supposedly our KDC). If the host/<host> service is unknown (i.e., 872 * the local keytab doesn't have it), and we cannot find another 873 * service we do have, let her in. 874 * 875 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 876 */ 877 /* ARGSUSED */ 878 static int 879 verify_krb_v5_tgt_begin(krb5_context context, char *pam_service, int debug, 880 const char **servicep, krb5_principal *princp __unused, char phost[static BUFSIZ]) 881 { 882 krb5_error_code retval; 883 krb5_principal princ; 884 krb5_keyblock *keyblock; 885 const char *services[3], **service; 886 887 *servicep = NULL; 888 889 if (debug) 890 openlog("pam_krb5", LOG_PID, LOG_AUTHPRIV); 891 892 /* If possible we want to try and verify the ticket we have 893 * received against a keytab. We will try multiple service 894 * principals, including at least the host principal and the PAM 895 * service principal. The host principal is preferred because access 896 * to that key is generally sufficient to compromise root, while the 897 * service key for this PAM service may be less carefully guarded. 898 * It is important to check the keytab first before the KDC so we do 899 * not get spoofed by a fake KDC. 900 */ 901 services[0] = "host"; 902 services[1] = pam_service; 903 services[2] = NULL; 904 keyblock = NULL; 905 retval = -1; 906 for (service = &services[0]; *service != NULL; service++) { 907 retval = krb5_sname_to_principal(context, NULL, *service, 908 KRB5_NT_SRV_HST, &princ); 909 if (retval != 0) { 910 if (debug) { 911 const char *msg = krb5_get_error_message( 912 context, retval); 913 syslog(LOG_DEBUG, 914 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 915 "krb5_sname_to_principal()", msg); 916 krb5_free_error_message(context, msg); 917 } 918 return -1; 919 } 920 921 /* Extract the name directly. */ 922 strncpy(phost, compat_princ_component(context, princ, 1), 923 BUFSIZ); 924 phost[BUFSIZ - 1] = '\0'; 925 926 /* 927 * Do we have service/<host> keys? 928 * (use default/configured keytab, kvno IGNORE_VNO to get the 929 * first match, and ignore enctype.) 930 */ 931 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 932 &keyblock); 933 if (retval != 0) 934 continue; 935 break; 936 } 937 if (keyblock) 938 krb5_free_keyblock(context, keyblock); 939 940 return (retval); 941 } 942 943 static int 944 verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 945 char *pam_service __unused, int debug, 946 const char *service, krb5_principal princ, char phost[static BUFSIZ]) 947 { 948 krb5_error_code retval; 949 krb5_auth_context auth_context = NULL; 950 krb5_data packet; 951 952 if (service == NULL) 953 return (0); /* uncertain, can't authenticate KDC */ 954 955 packet.data = 0; 956 957 /* Talk to the kdc and construct the ticket. */ 958 auth_context = NULL; 959 retval = krb5_mk_req(context, &auth_context, 0, service, phost, 960 NULL, ccache, &packet); 961 if (auth_context) { 962 krb5_auth_con_free(context, auth_context); 963 auth_context = NULL; /* setup for rd_req */ 964 } 965 if (retval) { 966 if (debug) { 967 const char *msg = krb5_get_error_message(context, 968 retval); 969 syslog(LOG_DEBUG, 970 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 971 "krb5_mk_req()", msg); 972 krb5_free_error_message(context, msg); 973 } 974 retval = -1; 975 goto cleanup; 976 } 977 978 /* Try to use the ticket. */ 979 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 980 NULL, NULL); 981 if (retval) { 982 if (debug) { 983 const char *msg = krb5_get_error_message(context, 984 retval); 985 syslog(LOG_DEBUG, 986 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 987 "krb5_rd_req()", msg); 988 krb5_free_error_message(context, msg); 989 } 990 retval = -1; 991 } 992 else 993 retval = 1; 994 995 cleanup: 996 if (packet.data) 997 compat_free_data_contents(context, &packet); 998 return (retval); 999 } 1000 1001 static void 1002 verify_krb_v5_tgt_cleanup(krb5_context context, int debug, 1003 const char *service, krb5_principal princ, char phost[static BUFSIZ] __unused) 1004 { 1005 1006 if (service) 1007 krb5_free_principal(context, princ); 1008 if (debug) 1009 closelog(); 1010 1011 } 1012 1013 /* Free the memory for cache_name. Called by pam_end() */ 1014 /* ARGSUSED */ 1015 static void 1016 cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 1017 { 1018 krb5_context krbctx; 1019 krb5_ccache ccache; 1020 krb5_error_code krbret; 1021 1022 if (krb5_init_context(&krbctx)) 1023 return; 1024 1025 krbret = krb5_cc_resolve(krbctx, data, &ccache); 1026 if (krbret == 0) 1027 krb5_cc_destroy(krbctx, ccache); 1028 krb5_free_context(krbctx); 1029 free(data); 1030 } 1031 1032 #ifdef COMPAT_HEIMDAL 1033 #ifdef COMPAT_MIT 1034 #error This cannot be MIT and Heimdal compatible! 1035 #endif 1036 #endif 1037 1038 #ifndef COMPAT_HEIMDAL 1039 #ifndef COMPAT_MIT 1040 #error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 1041 #endif 1042 #endif 1043 1044 #ifdef COMPAT_HEIMDAL 1045 /* ARGSUSED */ 1046 static const char * 1047 compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 1048 { 1049 return princ->name.name_string.val[n]; 1050 } 1051 1052 /* ARGSUSED */ 1053 static void 1054 compat_free_data_contents(krb5_context context __unused, krb5_data * data) 1055 { 1056 krb5_xfree(data->data); 1057 } 1058 #endif 1059 1060 #ifdef COMPAT_MIT 1061 static const char * 1062 compat_princ_component(krb5_context context, krb5_principal princ, int n) 1063 { 1064 return krb5_princ_component(context, princ, n)->data; 1065 } 1066 1067 static void 1068 compat_free_data_contents(krb5_context context, krb5_data * data) 1069 { 1070 krb5_free_data_contents(context, data); 1071 } 1072 #endif 1073