pam_krb5.c revision 1.20
1 /* $NetBSD: pam_krb5.c,v 1.20 2007/03/10 18:30:45 christos Exp $ */ 2 3 /*- 4 * This pam_krb5 module contains code that is: 5 * Copyright (c) Derrick J. Brashear, 1996. All rights reserved. 6 * Copyright (c) Frank Cusack, 1999-2001. All rights reserved. 7 * Copyright (c) Jacques A. Vidrine, 2000-2001. All rights reserved. 8 * Copyright (c) Nicolas Williams, 2001. All rights reserved. 9 * Copyright (c) Perot Systems Corporation, 2001. All rights reserved. 10 * Copyright (c) Mark R V Murray, 2001. All rights reserved. 11 * Copyright (c) Networks Associates Technology, Inc., 2002-2005. 12 * All rights reserved. 13 * 14 * Portions of this software were developed for the FreeBSD Project by 15 * ThinkSec AS and NAI Labs, the Security Research Division of Network 16 * Associates, Inc. under DARPA/SPAWAR contract N66001-01-C-8035 17 * ("CBOSS"), as part of the DARPA CHATS research program. 18 * 19 * Redistribution and use in source and binary forms, with or without 20 * modification, are permitted provided that the following conditions 21 * are met: 22 * 1. Redistributions of source code must retain the above copyright 23 * notices, and the entire permission notice in its entirety, 24 * including the disclaimer of warranties. 25 * 2. Redistributions in binary form must reproduce the above copyright 26 * notice, this list of conditions and the following disclaimer in the 27 * documentation and/or other materials provided with the distribution. 28 * 3. The name of the author may not be used to endorse or promote 29 * products derived from this software without specific prior 30 * written permission. 31 * 32 * ALTERNATIVELY, this product may be distributed under the terms of 33 * the GNU Public License, in which case the provisions of the GPL are 34 * required INSTEAD OF the above restrictions. (This clause is 35 * necessary due to a potential bad interaction between the GPL and 36 * the restrictions contained in a BSD-style copyright.) 37 * 38 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED 39 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 40 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 41 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, 42 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 43 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 44 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 45 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 46 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 47 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 48 * OF THE POSSIBILITY OF SUCH DAMAGE. 49 * 50 */ 51 52 #include <sys/cdefs.h> 53 #ifdef __FreeBSD__ 54 __FBSDID("$FreeBSD: src/lib/libpam/modules/pam_krb5/pam_krb5.c,v 1.22 2005/01/24 16:49:50 rwatson Exp $"); 55 #else 56 __RCSID("$NetBSD: pam_krb5.c,v 1.20 2007/03/10 18:30:45 christos Exp $"); 57 #endif 58 59 #include <sys/types.h> 60 #include <sys/stat.h> 61 #include <errno.h> 62 #include <limits.h> 63 #include <pwd.h> 64 #include <stdio.h> 65 #include <stdlib.h> 66 #include <string.h> 67 #include <syslog.h> 68 #include <unistd.h> 69 70 #include <krb5/krb5.h> 71 #include <krb5/com_err.h> 72 #include <krb5/parse_time.h> 73 74 #define PAM_SM_AUTH 75 #define PAM_SM_ACCOUNT 76 #define PAM_SM_PASSWORD 77 78 #include <security/pam_appl.h> 79 #include <security/pam_modules.h> 80 #include <security/pam_mod_misc.h> 81 #include <security/openpam.h> 82 83 #define COMPAT_HEIMDAL 84 /* #define COMPAT_MIT */ 85 86 static int verify_krb_v5_tgt(krb5_context, krb5_ccache, char *, int); 87 static void cleanup_cache(pam_handle_t *, void *, int); 88 static const char *compat_princ_component(krb5_context, krb5_principal, int); 89 static void compat_free_data_contents(krb5_context, krb5_data *); 90 91 #define USER_PROMPT "Username: " 92 #define PASSWORD_PROMPT "%s's Password:" 93 #define NEW_PASSWORD_PROMPT "New Password:" 94 95 #define PAM_OPT_CCACHE "ccache" 96 #define PAM_OPT_DEBUG "debug" 97 #define PAM_OPT_FORWARDABLE "forwardable" 98 #define PAM_OPT_RENEWABLE "renewable" 99 #define PAM_OPT_NO_CCACHE "no_ccache" 100 #define PAM_OPT_REUSE_CCACHE "reuse_ccache" 101 102 /* 103 * authentication management 104 */ 105 PAM_EXTERN int 106 pam_sm_authenticate(pam_handle_t *pamh, int flags __unused, 107 int argc __unused, const char *argv[] __unused) 108 { 109 krb5_error_code krbret; 110 krb5_context pam_context; 111 krb5_creds creds; 112 krb5_principal princ; 113 krb5_ccache ccache; 114 krb5_get_init_creds_opt opts; 115 struct passwd *pwd, pwres; 116 int retval; 117 void *ccache_data; 118 const char *user, *pass; 119 const void *sourceuser, *service; 120 char *principal, *princ_name, *ccache_name, luser[32], *srvdup; 121 char password_prompt[80]; 122 char pwbuf[1024]; 123 const char *rtime; 124 125 princ_name = NULL; 126 retval = pam_get_user(pamh, &user, USER_PROMPT); 127 if (retval != PAM_SUCCESS) 128 return (retval); 129 130 PAM_LOG("Got user: %s", user); 131 132 retval = pam_get_item(pamh, PAM_RUSER, &sourceuser); 133 if (retval != PAM_SUCCESS) 134 return (retval); 135 136 PAM_LOG("Got ruser: %s", (const char *)sourceuser); 137 138 service = NULL; 139 pam_get_item(pamh, PAM_SERVICE, &service); 140 if (service == NULL) 141 service = "unknown"; 142 143 PAM_LOG("Got service: %s", (const char *)service); 144 145 krbret = krb5_init_context(&pam_context); 146 if (krbret != 0) { 147 PAM_VERBOSE_ERROR("Kerberos 5 error"); 148 return (PAM_SERVICE_ERR); 149 } 150 151 PAM_LOG("Context initialised"); 152 153 krb5_get_init_creds_opt_init(&opts); 154 155 if (openpam_get_option(pamh, PAM_OPT_FORWARDABLE)) 156 krb5_get_init_creds_opt_set_forwardable(&opts, 1); 157 158 if ((rtime = openpam_get_option(pamh, PAM_OPT_RENEWABLE)) != NULL) { 159 krb5_deltat renew; 160 char rbuf[80], *rp; 161 162 if (*rtime) { 163 (void)strlcpy(rbuf, rtime, sizeof(rbuf)); 164 rtime = rbuf; 165 for (rp = rbuf; *rp; rp++) 166 if (*rp == '_') 167 *rp = ' '; 168 } 169 else 170 rtime = "1 month"; 171 renew = parse_time(rtime, "s"); 172 krb5_get_init_creds_opt_set_renew_life(&opts, renew); 173 } 174 175 176 177 PAM_LOG("Credentials initialised"); 178 179 krbret = krb5_cc_register(pam_context, &krb5_mcc_ops, FALSE); 180 if (krbret != 0 && krbret != KRB5_CC_TYPE_EXISTS) { 181 PAM_VERBOSE_ERROR("Kerberos 5 error"); 182 retval = PAM_SERVICE_ERR; 183 goto cleanup3; 184 } 185 186 PAM_LOG("Done krb5_cc_register()"); 187 188 /* Get principal name */ 189 if (openpam_get_option(pamh, PAM_OPT_AUTH_AS_SELF)) 190 asprintf(&principal, "%s/%s", (const char *)sourceuser, user); 191 else 192 principal = strdup(user); 193 194 PAM_LOG("Created principal: %s", principal); 195 196 krbret = krb5_parse_name(pam_context, principal, &princ); 197 free(principal); 198 if (krbret != 0) { 199 PAM_LOG("Error krb5_parse_name(): %s", 200 krb5_get_err_text(pam_context, krbret)); 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 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 210 if (krbret != 0) { 211 PAM_LOG("Error krb5_unparse_name(): %s", 212 krb5_get_err_text(pam_context, krbret)); 213 PAM_VERBOSE_ERROR("Kerberos 5 error"); 214 retval = PAM_SERVICE_ERR; 215 goto cleanup2; 216 } 217 218 PAM_LOG("Got principal: %s", princ_name); 219 220 /* Get password */ 221 (void) snprintf(password_prompt, sizeof(password_prompt), 222 PASSWORD_PROMPT, princ_name); 223 retval = pam_get_authtok(pamh, PAM_AUTHTOK, &pass, password_prompt); 224 if (retval != PAM_SUCCESS) 225 goto cleanup2; 226 227 PAM_LOG("Got password"); 228 229 /* Verify the local user exists (AFTER getting the password) */ 230 if (strchr(user, '@')) { 231 /* get a local account name for this principal */ 232 krbret = krb5_aname_to_localname(pam_context, princ, 233 sizeof(luser), luser); 234 if (krbret != 0) { 235 PAM_VERBOSE_ERROR("Kerberos 5 error"); 236 PAM_LOG("Error krb5_aname_to_localname(): %s", 237 krb5_get_err_text(pam_context, krbret)); 238 retval = PAM_USER_UNKNOWN; 239 goto cleanup2; 240 } 241 242 retval = pam_set_item(pamh, PAM_USER, luser); 243 if (retval != PAM_SUCCESS) 244 goto cleanup2; 245 246 PAM_LOG("PAM_USER Redone"); 247 } 248 249 if (getpwnam_r(user, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 || 250 pwd == NULL) { 251 retval = PAM_USER_UNKNOWN; 252 goto cleanup2; 253 } 254 255 PAM_LOG("Done getpwnam_r()"); 256 257 /* Get a TGT */ 258 memset(&creds, 0, sizeof(krb5_creds)); 259 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 260 pass, NULL, pamh, 0, NULL, &opts); 261 if (krbret != 0) { 262 PAM_VERBOSE_ERROR("Kerberos 5 error"); 263 PAM_LOG("Error krb5_get_init_creds_password(): %s", 264 krb5_get_err_text(pam_context, krbret)); 265 retval = PAM_AUTH_ERR; 266 goto cleanup2; 267 } 268 269 PAM_LOG("Got TGT"); 270 271 /* Generate a temporary cache */ 272 krbret = krb5_cc_gen_new(pam_context, &krb5_mcc_ops, &ccache); 273 if (krbret != 0) { 274 PAM_VERBOSE_ERROR("Kerberos 5 error"); 275 PAM_LOG("Error krb5_cc_gen_new(): %s", 276 krb5_get_err_text(pam_context, krbret)); 277 retval = PAM_SERVICE_ERR; 278 goto cleanup; 279 } 280 krbret = krb5_cc_initialize(pam_context, ccache, princ); 281 if (krbret != 0) { 282 PAM_VERBOSE_ERROR("Kerberos 5 error"); 283 PAM_LOG("Error krb5_cc_initialize(): %s", 284 krb5_get_err_text(pam_context, krbret)); 285 retval = PAM_SERVICE_ERR; 286 goto cleanup; 287 } 288 krbret = krb5_cc_store_cred(pam_context, ccache, &creds); 289 if (krbret != 0) { 290 PAM_VERBOSE_ERROR("Kerberos 5 error"); 291 PAM_LOG("Error krb5_cc_store_cred(): %s", 292 krb5_get_err_text(pam_context, krbret)); 293 krb5_cc_destroy(pam_context, ccache); 294 retval = PAM_SERVICE_ERR; 295 goto cleanup; 296 } 297 298 PAM_LOG("Credentials stashed"); 299 300 /* Verify them */ 301 if ((srvdup = strdup(service)) == NULL) { 302 retval = PAM_BUF_ERR; 303 goto cleanup; 304 } 305 krbret = verify_krb_v5_tgt(pam_context, ccache, srvdup, 306 openpam_get_option(pamh, PAM_OPT_DEBUG) ? 1 : 0); 307 free(srvdup); 308 if (krbret == -1) { 309 PAM_VERBOSE_ERROR("Kerberos 5 error"); 310 krb5_cc_destroy(pam_context, ccache); 311 retval = PAM_AUTH_ERR; 312 goto cleanup; 313 } 314 315 PAM_LOG("Credentials stash verified"); 316 317 retval = pam_get_data(pamh, "ccache", &ccache_data); 318 if (retval == PAM_SUCCESS) { 319 krb5_cc_destroy(pam_context, ccache); 320 PAM_VERBOSE_ERROR("Kerberos 5 error"); 321 retval = PAM_AUTH_ERR; 322 goto cleanup; 323 } 324 325 PAM_LOG("Credentials stash not pre-existing"); 326 327 asprintf(&ccache_name, "%s:%s", krb5_cc_get_type(pam_context, 328 ccache), krb5_cc_get_name(pam_context, ccache)); 329 if (ccache_name == NULL) { 330 PAM_VERBOSE_ERROR("Kerberos 5 error"); 331 retval = PAM_BUF_ERR; 332 goto cleanup; 333 } 334 retval = pam_set_data(pamh, "ccache", ccache_name, cleanup_cache); 335 if (retval != 0) { 336 krb5_cc_destroy(pam_context, ccache); 337 PAM_VERBOSE_ERROR("Kerberos 5 error"); 338 retval = PAM_SERVICE_ERR; 339 goto cleanup; 340 } 341 342 PAM_LOG("Credentials stash saved"); 343 344 cleanup: 345 krb5_free_cred_contents(pam_context, &creds); 346 PAM_LOG("Done cleanup"); 347 cleanup2: 348 krb5_free_principal(pam_context, princ); 349 PAM_LOG("Done cleanup2"); 350 cleanup3: 351 if (princ_name) 352 free(princ_name); 353 354 krb5_free_context(pam_context); 355 356 PAM_LOG("Done cleanup3"); 357 358 if (retval != PAM_SUCCESS) 359 PAM_VERBOSE_ERROR("Kerberos 5 refuses you"); 360 361 return (retval); 362 } 363 364 PAM_EXTERN int 365 pam_sm_setcred(pam_handle_t *pamh, int flags, 366 int argc __unused, const char *argv[] __unused) 367 { 368 369 krb5_error_code krbret; 370 krb5_context pam_context; 371 krb5_principal princ; 372 krb5_creds creds; 373 krb5_ccache ccache_temp, ccache_perm; 374 krb5_cc_cursor cursor; 375 struct passwd *pwd = NULL, pwres; 376 int retval; 377 const char *cache_name, *q; 378 const void *user; 379 void *cache_data; 380 char *cache_name_buf = NULL, *p, *cache_name_buf2 = NULL; 381 char pwbuf[1024]; 382 383 uid_t euid; 384 gid_t egid; 385 386 if (flags & PAM_DELETE_CRED) 387 return (PAM_SUCCESS); /* XXX */ 388 389 if (!(flags & (PAM_REFRESH_CRED|PAM_REINITIALIZE_CRED|PAM_ESTABLISH_CRED))) 390 return (PAM_SERVICE_ERR); 391 392 /* If a persistent cache isn't desired, stop now. */ 393 if (openpam_get_option(pamh, PAM_OPT_NO_CCACHE)) 394 return (PAM_SUCCESS); 395 396 PAM_LOG("Establishing credentials"); 397 398 /* Get username */ 399 retval = pam_get_item(pamh, PAM_USER, &user); 400 if (retval != PAM_SUCCESS) 401 return (retval); 402 403 PAM_LOG("Got user: %s", (const char *)user); 404 405 krbret = krb5_init_context(&pam_context); 406 if (krbret != 0) { 407 PAM_LOG("Error krb5_init_context() failed"); 408 return (PAM_SERVICE_ERR); 409 } 410 411 PAM_LOG("Context initialised"); 412 413 euid = geteuid(); /* Usually 0 */ 414 egid = getegid(); 415 416 PAM_LOG("Got euid, egid: %d %d", euid, egid); 417 418 /* Retrieve the temporary cache */ 419 retval = pam_get_data(pamh, "ccache", &cache_data); 420 if (retval != PAM_SUCCESS) { 421 retval = PAM_CRED_UNAVAIL; 422 goto cleanup3; 423 } 424 krbret = krb5_cc_resolve(pam_context, cache_data, &ccache_temp); 425 if (krbret != 0) { 426 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)cache_data, 427 krb5_get_err_text(pam_context, krbret)); 428 retval = PAM_SERVICE_ERR; 429 goto cleanup3; 430 } 431 432 /* Get the uid. This should exist. */ 433 if (getpwnam_r(user, &pwres, pwbuf, sizeof(pwbuf), &pwd) != 0 || 434 pwd == NULL) { 435 retval = PAM_USER_UNKNOWN; 436 goto cleanup3; 437 } 438 439 PAM_LOG("Done getpwnam_r()"); 440 441 /* Avoid following a symlink as root */ 442 if (setegid(pwd->pw_gid)) { 443 retval = PAM_SERVICE_ERR; 444 goto cleanup3; 445 } 446 if (seteuid(pwd->pw_uid)) { 447 retval = PAM_SERVICE_ERR; 448 goto cleanup3; 449 } 450 451 PAM_LOG("Done setegid() & seteuid()"); 452 453 if (flags & (PAM_REFRESH_CRED|PAM_REINITIALIZE_CRED)) { 454 cache_name = getenv("KRB5CCNAME"); 455 if (!cache_name) 456 goto cleanup3; 457 } else { 458 /* Get the cache name */ 459 cache_name = openpam_get_option(pamh, PAM_OPT_CCACHE); 460 if (cache_name == NULL) { 461 asprintf(&cache_name_buf, "FILE:/tmp/krb5cc_%d", pwd->pw_uid); 462 cache_name = cache_name_buf; 463 } 464 465 /* XXX potential overflow */ 466 cache_name_buf2 = p = calloc(PATH_MAX + 16, sizeof(char)); 467 q = cache_name; 468 469 if (p == NULL) { 470 PAM_LOG("Error malloc(): failure"); 471 retval = PAM_BUF_ERR; 472 goto cleanup3; 473 } 474 cache_name = p; 475 476 /* convert %u and %p */ 477 while (*q) { 478 if (*q == '%') { 479 q++; 480 if (*q == 'u') { 481 sprintf(p, "%d", pwd->pw_uid); 482 p += strlen(p); 483 } 484 else if (*q == 'p') { 485 sprintf(p, "%d", getpid()); 486 p += strlen(p); 487 } 488 else { 489 /* Not a special token */ 490 *p++ = '%'; 491 q--; 492 } 493 q++; 494 } 495 else { 496 *p++ = *q++; 497 } 498 } 499 } 500 501 PAM_LOG("Got cache_name: %s", cache_name); 502 503 /* Initialize the new ccache */ 504 krbret = krb5_cc_get_principal(pam_context, ccache_temp, &princ); 505 if (krbret != 0) { 506 PAM_LOG("Error krb5_cc_get_principal(): %s", 507 krb5_get_err_text(pam_context, krbret)); 508 retval = PAM_SERVICE_ERR; 509 goto cleanup3; 510 } 511 krbret = krb5_cc_resolve(pam_context, cache_name, &ccache_perm); 512 if (krbret != 0) { 513 PAM_LOG("Error krb5_cc_resolve(): %s", 514 krb5_get_err_text(pam_context, krbret)); 515 retval = PAM_SERVICE_ERR; 516 goto cleanup2; 517 } 518 519 krbret = krb5_cc_initialize(pam_context, ccache_perm, princ); 520 if (krbret != 0) { 521 PAM_LOG("Error krb5_cc_initialize(): %s", 522 krb5_get_err_text(pam_context, krbret)); 523 retval = PAM_SERVICE_ERR; 524 goto cleanup2; 525 } 526 527 PAM_LOG("Cache initialised"); 528 529 /* Prepare for iteration over creds */ 530 krbret = krb5_cc_start_seq_get(pam_context, ccache_temp, &cursor); 531 if (krbret != 0) { 532 PAM_LOG("Error krb5_cc_start_seq_get(): %s", 533 krb5_get_err_text(pam_context, krbret)); 534 krb5_cc_destroy(pam_context, ccache_perm); 535 retval = PAM_SERVICE_ERR; 536 goto cleanup2; 537 } 538 539 PAM_LOG("Prepared for iteration"); 540 541 /* Copy the creds (should be two of them) */ 542 while ((krbret = krb5_cc_next_cred(pam_context, ccache_temp, 543 &cursor, &creds) == 0)) { 544 545 krbret = krb5_cc_store_cred(pam_context, ccache_perm, &creds); 546 if (krbret != 0) { 547 PAM_LOG("Error krb5_cc_store_cred(): %s", 548 krb5_get_err_text(pam_context, krbret)); 549 krb5_cc_destroy(pam_context, ccache_perm); 550 krb5_free_cred_contents(pam_context, &creds); 551 retval = PAM_SERVICE_ERR; 552 goto cleanup2; 553 } 554 555 krb5_free_cred_contents(pam_context, &creds); 556 PAM_LOG("Iteration"); 557 } 558 559 krb5_cc_end_seq_get(pam_context, ccache_temp, &cursor); 560 561 PAM_LOG("Done iterating"); 562 563 if (flags & PAM_ESTABLISH_CRED) { 564 if (strstr(cache_name, "FILE:") == cache_name) { 565 if (chown(&cache_name[5], pwd->pw_uid, pwd->pw_gid) == -1) { 566 PAM_LOG("Error chown(): %s", strerror(errno)); 567 krb5_cc_destroy(pam_context, ccache_perm); 568 retval = PAM_SERVICE_ERR; 569 goto cleanup2; 570 } 571 PAM_LOG("Done chown()"); 572 573 if (chmod(&cache_name[5], (S_IRUSR | S_IWUSR)) == -1) { 574 PAM_LOG("Error chmod(): %s", strerror(errno)); 575 krb5_cc_destroy(pam_context, ccache_perm); 576 retval = PAM_SERVICE_ERR; 577 goto cleanup2; 578 } 579 PAM_LOG("Done chmod()"); 580 } 581 } 582 583 krb5_cc_close(pam_context, ccache_perm); 584 585 PAM_LOG("Cache closed"); 586 587 retval = pam_setenv(pamh, "KRB5CCNAME", cache_name, 1); 588 if (retval != PAM_SUCCESS) { 589 PAM_LOG("Error pam_setenv(): %s", pam_strerror(pamh, retval)); 590 retval = PAM_SERVICE_ERR; 591 goto cleanup2; 592 } 593 594 PAM_LOG("Environment done: KRB5CCNAME=%s", cache_name); 595 596 cleanup2: 597 krb5_free_principal(pam_context, princ); 598 PAM_LOG("Done cleanup2"); 599 cleanup3: 600 krb5_free_context(pam_context); 601 PAM_LOG("Done cleanup3"); 602 603 seteuid(euid); 604 setegid(egid); 605 606 PAM_LOG("Done seteuid() & setegid()"); 607 608 if (cache_name_buf != NULL) 609 free(cache_name_buf); 610 if (cache_name_buf2 != NULL) 611 free(cache_name_buf2); 612 613 return (retval); 614 } 615 616 /* 617 * account management 618 */ 619 PAM_EXTERN int 620 pam_sm_acct_mgmt(pam_handle_t *pamh, int flags __unused, 621 int argc __unused, const char *argv[] __unused) 622 { 623 krb5_error_code krbret; 624 krb5_context pam_context; 625 krb5_ccache ccache; 626 krb5_principal princ; 627 int retval; 628 const void *user; 629 void *ccache_name; 630 631 retval = pam_get_item(pamh, PAM_USER, &user); 632 if (retval != PAM_SUCCESS) 633 return (retval); 634 635 PAM_LOG("Got user: %s", (const char *)user); 636 637 retval = pam_get_data(pamh, "ccache", &ccache_name); 638 if (retval != PAM_SUCCESS) 639 return (PAM_SUCCESS); 640 641 PAM_LOG("Got credentials"); 642 643 krbret = krb5_init_context(&pam_context); 644 if (krbret != 0) { 645 PAM_LOG("Error krb5_init_context() failed"); 646 return (PAM_PERM_DENIED); 647 } 648 649 PAM_LOG("Context initialised"); 650 651 krbret = krb5_cc_resolve(pam_context, (const char *)ccache_name, &ccache); 652 if (krbret != 0) { 653 PAM_LOG("Error krb5_cc_resolve(\"%s\"): %s", (const char *)ccache_name, 654 krb5_get_err_text(pam_context, krbret)); 655 krb5_free_context(pam_context); 656 return (PAM_PERM_DENIED); 657 } 658 659 PAM_LOG("Got ccache %s", (const char *)ccache_name); 660 661 662 krbret = krb5_cc_get_principal(pam_context, ccache, &princ); 663 if (krbret != 0) { 664 PAM_LOG("Error krb5_cc_get_principal(): %s", 665 krb5_get_err_text(pam_context, krbret)); 666 retval = PAM_PERM_DENIED;; 667 goto cleanup; 668 } 669 670 PAM_LOG("Got principal"); 671 672 if (krb5_kuserok(pam_context, princ, (const char *)user)) 673 retval = PAM_SUCCESS; 674 else 675 retval = PAM_PERM_DENIED; 676 krb5_free_principal(pam_context, princ); 677 678 PAM_LOG("Done kuserok()"); 679 680 cleanup: 681 krb5_free_context(pam_context); 682 PAM_LOG("Done cleanup"); 683 684 return (retval); 685 686 } 687 688 /* 689 * password management 690 */ 691 PAM_EXTERN int 692 pam_sm_chauthtok(pam_handle_t *pamh, int flags, 693 int argc __unused, const char *argv[] __unused) 694 { 695 krb5_error_code krbret; 696 krb5_context pam_context; 697 krb5_creds creds; 698 krb5_principal princ; 699 krb5_get_init_creds_opt opts; 700 krb5_data result_code_string, result_string; 701 int result_code, retval; 702 const char *pass; 703 const void *user; 704 char *princ_name, *passdup; 705 char password_prompt[80]; 706 707 princ_name = NULL; 708 if (flags & PAM_PRELIM_CHECK) { 709 /* Nothing to do here. */ 710 return (PAM_SUCCESS); 711 } 712 713 if (!(flags & PAM_UPDATE_AUTHTOK)) { 714 PAM_LOG("Illegal flags argument"); 715 return (PAM_ABORT); 716 } 717 718 retval = pam_get_item(pamh, PAM_USER, &user); 719 if (retval != PAM_SUCCESS) 720 return (retval); 721 722 PAM_LOG("Got user: %s", (const char *)user); 723 724 krbret = krb5_init_context(&pam_context); 725 if (krbret != 0) { 726 PAM_LOG("Error krb5_init_context() failed"); 727 return (PAM_SERVICE_ERR); 728 } 729 730 PAM_LOG("Context initialised"); 731 732 krb5_get_init_creds_opt_init(&opts); 733 734 krb5_get_init_creds_opt_set_tkt_life(&opts, 300); 735 krb5_get_init_creds_opt_set_forwardable(&opts, FALSE); 736 krb5_get_init_creds_opt_set_proxiable(&opts, FALSE); 737 738 PAM_LOG("Credentials options initialised"); 739 740 /* Get principal name */ 741 krbret = krb5_parse_name(pam_context, (const char *)user, &princ); 742 if (krbret != 0) { 743 PAM_LOG("Error krb5_parse_name(): %s", 744 krb5_get_err_text(pam_context, krbret)); 745 retval = PAM_USER_UNKNOWN; 746 goto cleanup3; 747 } 748 749 /* Now convert the principal name into something human readable */ 750 krbret = krb5_unparse_name(pam_context, princ, &princ_name); 751 if (krbret != 0) { 752 PAM_LOG("Error krb5_unparse_name(): %s", 753 krb5_get_err_text(pam_context, krbret)); 754 retval = PAM_SERVICE_ERR; 755 goto cleanup2; 756 } 757 758 PAM_LOG("Got principal: %s", princ_name); 759 760 /* Get password */ 761 (void) snprintf(password_prompt, sizeof(password_prompt), 762 PASSWORD_PROMPT, princ_name); 763 retval = pam_get_authtok(pamh, PAM_OLDAUTHTOK, &pass, password_prompt); 764 if (retval != PAM_SUCCESS) 765 goto cleanup2; 766 767 PAM_LOG("Got password"); 768 769 memset(&creds, 0, sizeof(krb5_creds)); 770 krbret = krb5_get_init_creds_password(pam_context, &creds, princ, 771 pass, NULL, pamh, 0, "kadmin/changepw", &opts); 772 if (krbret != 0) { 773 PAM_LOG("Error krb5_get_init_creds_password(): %s", 774 krb5_get_err_text(pam_context, krbret)); 775 retval = PAM_AUTH_ERR; 776 goto cleanup2; 777 } 778 779 PAM_LOG("Credentials established"); 780 781 /* Now get the new password */ 782 for (;;) { 783 retval = pam_get_authtok(pamh, 784 PAM_AUTHTOK, &pass, NEW_PASSWORD_PROMPT); 785 if (retval != PAM_TRY_AGAIN) 786 break; 787 pam_error(pamh, "Mismatch; try again, EOF to quit."); 788 } 789 if (retval != PAM_SUCCESS) 790 goto cleanup; 791 792 PAM_LOG("Got new password"); 793 794 /* Change it */ 795 if ((passdup = strdup(pass)) == NULL) { 796 retval = PAM_BUF_ERR; 797 goto cleanup; 798 } 799 800 krb5_data_zero(&result_code_string); 801 krb5_data_zero(&result_string); 802 803 krbret = krb5_change_password(pam_context, &creds, passdup, 804 &result_code, &result_code_string, &result_string); 805 free(passdup); 806 if (krbret != 0) { 807 pam_error(pamh, "Unable to set password: %s", 808 krb5_get_err_text(pam_context, krbret)); 809 retval = PAM_AUTHTOK_ERR; 810 goto cleanup; 811 } 812 if (result_code) { 813 pam_info(pamh, "%s%s%.*s", 814 krb5_passwd_result_to_string(pam_context, result_code), 815 result_string.length > 0 ? ": " : "", 816 (int)result_string.length, 817 result_string.length > 0 ? (char *)result_string.data : ""); 818 retval = PAM_AUTHTOK_ERR; 819 } else { 820 PAM_LOG("Password changed"); 821 } 822 823 krb5_data_free(&result_string); 824 krb5_data_free(&result_code_string); 825 826 cleanup: 827 krb5_free_cred_contents(pam_context, &creds); 828 PAM_LOG("Done cleanup"); 829 cleanup2: 830 krb5_free_principal(pam_context, princ); 831 PAM_LOG("Done cleanup2"); 832 cleanup3: 833 if (princ_name) 834 free(princ_name); 835 836 krb5_free_context(pam_context); 837 838 PAM_LOG("Done cleanup3"); 839 840 return (retval); 841 } 842 843 PAM_MODULE_ENTRY("pam_krb5"); 844 845 /* 846 * This routine with some modification is from the MIT V5B6 appl/bsd/login.c 847 * Modified by Sam Hartman <hartmans (at) mit.edu> to support PAM services 848 * for Debian. 849 * 850 * Verify the Kerberos ticket-granting ticket just retrieved for the 851 * user. If the Kerberos server doesn't respond, assume the user is 852 * trying to fake us out (since we DID just get a TGT from what is 853 * supposedly our KDC). If the host/<host> service is unknown (i.e., 854 * the local keytab doesn't have it), and we cannot find another 855 * service we do have, let her in. 856 * 857 * Returns 1 for confirmation, -1 for failure, 0 for uncertainty. 858 */ 859 /* ARGSUSED */ 860 static int 861 verify_krb_v5_tgt(krb5_context context, krb5_ccache ccache, 862 char *pam_service, int debug) 863 { 864 krb5_error_code retval; 865 krb5_principal princ; 866 krb5_keyblock *keyblock; 867 krb5_data packet; 868 krb5_auth_context auth_context = NULL; 869 char phost[BUFSIZ]; 870 const char *services[3], **service; 871 struct syslog_data data = SYSLOG_DATA_INIT; 872 873 packet.data = 0; 874 875 if (debug) 876 openlog_r("pam_krb5", LOG_PID, LOG_AUTHPRIV, &data); 877 878 /* If possible we want to try and verify the ticket we have 879 * received against a keytab. We will try multiple service 880 * principals, including at least the host principal and the PAM 881 * service principal. The host principal is preferred because access 882 * to that key is generally sufficient to compromise root, while the 883 * service key for this PAM service may be less carefully guarded. 884 * It is important to check the keytab first before the KDC so we do 885 * not get spoofed by a fake KDC. 886 */ 887 services[0] = "host"; 888 services[1] = pam_service; 889 services[2] = NULL; 890 keyblock = 0; 891 retval = -1; 892 for (service = &services[0]; *service != NULL; service++) { 893 retval = krb5_sname_to_principal(context, NULL, *service, 894 KRB5_NT_SRV_HST, &princ); 895 if (retval != 0) { 896 if (debug) 897 syslog_r(LOG_DEBUG, &data, 898 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 899 "krb5_sname_to_principal()", 900 krb5_get_err_text(context, retval)); 901 return -1; 902 } 903 904 /* Extract the name directly. */ 905 strncpy(phost, compat_princ_component(context, princ, 1), 906 BUFSIZ); 907 phost[BUFSIZ - 1] = '\0'; 908 909 /* 910 * Do we have service/<host> keys? 911 * (use default/configured keytab, kvno IGNORE_VNO to get the 912 * first match, and ignore enctype.) 913 */ 914 retval = krb5_kt_read_service_key(context, NULL, princ, 0, 0, 915 &keyblock); 916 if (retval != 0) 917 continue; 918 break; 919 } 920 if (retval != 0) { /* failed to find key */ 921 /* Keytab or service key does not exist */ 922 if (debug) 923 syslog_r(LOG_DEBUG, &data, 924 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 925 "krb5_kt_read_service_key()", 926 krb5_get_err_text(context, retval)); 927 retval = 0; 928 goto cleanup; 929 } 930 if (keyblock) 931 krb5_free_keyblock(context, keyblock); 932 933 /* Talk to the kdc and construct the ticket. */ 934 auth_context = NULL; 935 retval = krb5_mk_req(context, &auth_context, 0, *service, phost, 936 NULL, ccache, &packet); 937 if (auth_context) { 938 krb5_auth_con_free(context, auth_context); 939 auth_context = NULL; /* setup for rd_req */ 940 } 941 if (retval) { 942 if (debug) 943 syslog_r(LOG_DEBUG, &data, 944 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 945 "krb5_mk_req()", 946 krb5_get_err_text(context, retval)); 947 retval = -1; 948 goto cleanup; 949 } 950 951 /* Try to use the ticket. */ 952 retval = krb5_rd_req(context, &auth_context, &packet, princ, NULL, 953 NULL, NULL); 954 if (retval) { 955 if (debug) 956 syslog_r(LOG_DEBUG, &data, 957 "pam_krb5: verify_krb_v5_tgt(): %s: %s", 958 "krb5_rd_req()", 959 krb5_get_err_text(context, retval)); 960 retval = -1; 961 } 962 else 963 retval = 1; 964 965 cleanup: 966 if (debug) 967 closelog_r(&data); 968 if (packet.data) 969 compat_free_data_contents(context, &packet); 970 if (auth_context) { 971 krb5_auth_con_free(context, auth_context); 972 auth_context = NULL; /* setup for rd_req */ 973 } 974 krb5_free_principal(context, princ); 975 return retval; 976 } 977 978 /* Free the memory for cache_name. Called by pam_end() */ 979 /* ARGSUSED */ 980 static void 981 cleanup_cache(pam_handle_t *pamh __unused, void *data, int pam_end_status __unused) 982 { 983 krb5_context pam_context; 984 krb5_ccache ccache; 985 krb5_error_code krbret; 986 987 if (krb5_init_context(&pam_context)) 988 return; 989 990 krbret = krb5_cc_resolve(pam_context, data, &ccache); 991 if (krbret == 0) 992 krb5_cc_destroy(pam_context, ccache); 993 krb5_free_context(pam_context); 994 free(data); 995 } 996 997 #ifdef COMPAT_HEIMDAL 998 #ifdef COMPAT_MIT 999 #error This cannot be MIT and Heimdal compatible! 1000 #endif 1001 #endif 1002 1003 #ifndef COMPAT_HEIMDAL 1004 #ifndef COMPAT_MIT 1005 #error One of COMPAT_MIT and COMPAT_HEIMDAL must be specified! 1006 #endif 1007 #endif 1008 1009 #ifdef COMPAT_HEIMDAL 1010 /* ARGSUSED */ 1011 static const char * 1012 compat_princ_component(krb5_context context __unused, krb5_principal princ, int n) 1013 { 1014 return princ->name.name_string.val[n]; 1015 } 1016 1017 /* ARGSUSED */ 1018 static void 1019 compat_free_data_contents(krb5_context context __unused, krb5_data * data) 1020 { 1021 krb5_xfree(data->data); 1022 } 1023 #endif 1024 1025 #ifdef COMPAT_MIT 1026 static const char * 1027 compat_princ_component(krb5_context context, krb5_principal princ, int n) 1028 { 1029 return krb5_princ_component(context, princ, n)->data; 1030 } 1031 1032 static void 1033 compat_free_data_contents(krb5_context context, krb5_data * data) 1034 { 1035 krb5_free_data_contents(context, data); 1036 } 1037 #endif 1038
Indexes created Mon Sep 29 21:09:56 GMT 2025