2 * Adapted in part from MIT Kerberos 5-1.2.1 slave/kprop.c and from
3 * http://docs.sun.com/?p=/doc/816-1331/6m7oo9sms&a=view
5 * Copyright (c) 2002-2004 The Regents of the University of Michigan.
8 * Andy Adamson <andros@umich.edu>
9 * J. Bruce Fields <bfields@umich.edu>
10 * Marius Aamodt Eriksen <marius@umich.edu>
11 * Kevin Coffman <kwc@umich.edu>
17 * Copyright 1990,1991 by the Massachusetts Institute of Technology.
18 * All Rights Reserved.
20 * Export of this software from the United States of America may
21 * require a specific license from the United States Government.
22 * It is the responsibility of any person or organization contemplating
23 * export to obtain such a license before exporting.
25 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
26 * distribute this software and its documentation for any purpose and
27 * without fee is hereby granted, provided that the above copyright
28 * notice appear in all copies and that both that copyright notice and
29 * this permission notice appear in supporting documentation, and that
30 * the name of M.I.T. not be used in advertising or publicity pertaining
31 * to distribution of the software without specific, written prior
32 * permission. Furthermore if you modify this software you must label
33 * your software as modified software and not distribute it in such a
34 * fashion that it might be confused with the original M.I.T. software.
35 * M.I.T. makes no representations about the suitability of
36 * this software for any purpose. It is provided "as is" without express
37 * or implied warranty.
41 * Copyright 1994 by OpenVision Technologies, Inc.
43 * Permission to use, copy, modify, distribute, and sell this software
44 * and its documentation for any purpose is hereby granted without fee,
45 * provided that the above copyright notice appears in all copies and
46 * that both that copyright notice and this permission notice appear in
47 * supporting documentation, and that the name of OpenVision not be used
48 * in advertising or publicity pertaining to distribution of the software
49 * without specific, written prior permission. OpenVision makes no
50 * representations about the suitability of this software for any
51 * purpose. It is provided "as is" without express or implied warranty.
53 * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
54 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
55 * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
56 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
57 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
58 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
59 * PERFORMANCE OF THIS SOFTWARE.
64 Copyright (c) 2004 The Regents of the University of Michigan.
67 Redistribution and use in source and binary forms, with or without
68 modification, are permitted provided that the following conditions
71 1. Redistributions of source code must retain the above copyright
72 notice, this list of conditions and the following disclaimer.
73 2. Redistributions in binary form must reproduce the above copyright
74 notice, this list of conditions and the following disclaimer in the
75 documentation and/or other materials provided with the distribution.
76 3. Neither the name of the University nor the names of its
77 contributors may be used to endorse or promote products derived
78 from this software without specific prior written permission.
80 THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
81 WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
82 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
83 DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
84 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
85 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
86 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
87 BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
88 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
89 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
90 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
98 #include <sys/param.h>
100 #include <sys/stat.h>
101 #include <sys/socket.h>
102 #include <arpa/inet.h>
110 #include <gssapi/gssapi.h>
111 #ifdef USE_PRIVATE_KRB5_FUNCTIONS
112 #include <gssapi/gssapi_krb5.h>
115 #include <rpc/auth_gss.h>
118 #include "err_util.h"
119 #include "gss_util.h"
120 #include "gss_oids.h"
121 #include "krb5_util.h"
123 /* Global list of principals/cache file names for machine credentials */
124 struct gssd_k5_kt_princ *gssd_k5_kt_princ_list = NULL;
126 /*==========================*/
127 /*=== Internal routines ===*/
128 /*==========================*/
130 static int select_krb5_ccache(const struct dirent *d);
131 static int gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d);
132 static int gssd_get_single_krb5_cred(krb5_context context,
133 krb5_keytab kt, struct gssd_k5_kt_princ *ple);
134 static int gssd_have_realm_ple(krb5_data *realm);
135 static int gssd_process_krb5_keytab(krb5_context context, krb5_keytab kt,
139 * Called from the scandir function to weed out potential krb5
140 * credentials cache files
143 * 0 => don't select this one
144 * 1 => select this one
147 select_krb5_ccache(const struct dirent *d)
149 /* Don't consider anything but regular files. (No symlinks, etc.) */
150 if (d->d_type != DT_REG)
153 if (strstr(d->d_name, GSSD_DEFAULT_CRED_PREFIX))
160 * Look in the GSSD_DEFAULT_CRED_DIR for files that look like they
161 * are Kerberos Credential Cache files for a given UID. Return
162 * non-zero and the dirent pointer for the entry most likely to be
163 * what we want. Otherwise, return zero and no dirent pointer.
164 * The caller is responsible for freeing the dirent if one is returned.
167 * 0 => could not find an existing entry
168 * 1 => found an existing entry
171 gssd_find_existing_krb5_ccache(uid_t uid, struct dirent **d)
173 struct dirent **namelist;
177 struct dirent *best_match_dir = NULL;
178 struct stat best_match_stat, tmp_stat;
181 n = scandir(GSSD_DEFAULT_CRED_DIR, &namelist, select_krb5_ccache, 0);
183 perror("scandir looking for krb5 credentials caches");
188 snprintf(substring, sizeof(substring), "_%d", uid);
189 for (i = 0; i < n; i++) {
190 printerr(3, "CC file '%s' being considered\n",
191 namelist[i]->d_name);
192 if (strstr(namelist[i]->d_name, substring)) {
193 snprintf(statname, sizeof(statname),
194 "%s/%s", GSSD_DEFAULT_CRED_DIR,
195 namelist[i]->d_name);
196 if (stat(statname, &tmp_stat)) {
197 printerr(0, "Error doing stat "
202 printerr(3, "CC file '%s' matches "
203 "name check and has "
207 /* if more than one match is found,
208 * return the most recent (the one
209 * with the latest mtime),
210 * and don't free the dirent */
212 best_match_dir = namelist[i];
213 best_match_stat = tmp_stat;
218 * If the current match has
219 * an mtime later than the
220 * one we are looking at,
221 * then use the current match.
222 * Otherwise, we still have
225 if (tmp_stat.st_mtime >
226 best_match_stat.st_mtime) {
227 free(best_match_dir);
228 best_match_dir = namelist[i];
229 best_match_stat = tmp_stat;
234 printerr(3, "CC file '%s' is our "
235 "current best match "
236 "with mtime of %u\n",
237 best_match_dir->d_name,
238 best_match_stat.st_mtime);
254 #ifdef HAVE_SET_ALLOWABLE_ENCTYPES
256 * this routine obtains a credentials handle via gss_acquire_cred()
257 * then calls gss_krb5_set_allowable_enctypes() to limit the encryption
260 * XXX Should call some function to determine the enctypes supported
261 * by the kernel. (Only need to do that once!)
265 * -1 => there was an error
269 limit_krb5_enctypes(struct rpc_gss_sec *sec, uid_t uid)
271 u_int maj_stat, min_stat;
273 /* krb5_enctype enctypes[] = {ENCTYPE_DES3_CBC_SHA1};
274 ENCTYPE_ARCFOUR_HMAC, */
275 krb5_enctype enctypes[] = {ENCTYPE_DES3_CBC_SHA1,
277 ENCTYPE_DES_CBC_CRC};
278 int num_enctypes = sizeof(enctypes) / sizeof(enctypes[0]);
280 maj_stat = gss_acquire_cred(&min_stat, NULL, 0,
281 GSS_C_NULL_OID_SET, GSS_C_INITIATE,
284 if (maj_stat != GSS_S_COMPLETE) {
285 printerr(0, "WARNING: error from gss_acquire_cred "
286 "for user with uid %d (%s)\n",
287 uid, error_message(min_stat));
291 maj_stat = gss_set_allowable_enctypes(&min_stat, credh, &krb5oid,
292 num_enctypes, &enctypes);
293 if (maj_stat != GSS_S_COMPLETE) {
294 printerr(0, "WARNING: error from gss_set_allowable_enctypes "
295 "for user with uid %d (%s)\n",
296 uid, error_message(min_stat));
303 #endif /* HAVE_SET_ALLOWABLE_ENCTYPES */
306 * Obtain credentials via a key in the keytab given
307 * a keytab handle and a gssd_k5_kt_princ structure.
308 * Checks to see if current credentials are expired,
309 * if not, uses the keytab to obtain new credentials.
312 * 0 => success (or credentials have not expired)
316 gssd_get_single_krb5_cred(krb5_context context,
318 struct gssd_k5_kt_princ *ple)
320 krb5_get_init_creds_opt options;
322 krb5_ccache ccache = NULL;
323 char kt_name[BUFSIZ];
324 char cc_name[BUFSIZ];
326 time_t now = time(0);
328 memset(&my_creds, 0, sizeof(my_creds));
330 if (ple->ccname && ple->endtime > now) {
331 printerr(2, "INFO: Credentials in CC '%s' are good until %d\n",
332 ple->ccname, ple->endtime);
337 if ((code = krb5_kt_get_name(context, kt, kt_name, BUFSIZ))) {
338 printerr(0, "ERROR: Unable to get keytab name in "
339 "gssd_get_single_krb5_cred\n");
343 krb5_get_init_creds_opt_init(&options);
344 krb5_get_init_creds_opt_set_address_list(&options, NULL);
346 #ifdef TEST_SHORT_LIFETIME
347 /* set a short lifetime (for debugging only!) */
348 printerr(0, "WARNING: Using (debug) short machine cred lifetime!\n");
349 krb5_get_init_creds_opt_set_tkt_life(&options, 5*60);
351 if ((code = krb5_get_init_creds_keytab(context, &my_creds, ple->princ,
352 kt, 0, 0, &options))) {
354 if ((krb5_unparse_name(context, ple->princ, &pname))) {
357 printerr(0, "WARNING: %s while getting initial ticket for "
358 "principal '%s' from keytab '%s'\n",
360 pname ? pname : "<unparsable>", kt_name);
361 if (pname) krb5_free_unparsed_name(context, pname);
366 * Initialize cache file which we're going to be using
369 snprintf(cc_name, sizeof(cc_name), "FILE:%s/%s%s_%s",
370 GSSD_DEFAULT_CRED_DIR, GSSD_DEFAULT_CRED_PREFIX,
371 GSSD_DEFAULT_MACHINE_CRED_SUFFIX, ple->realm);
372 ple->endtime = my_creds.times.endtime;
373 ple->ccname = strdup(cc_name);
374 if (ple->ccname == NULL) {
375 printerr(0, "ERROR: no storage to duplicate credentials "
380 if ((code = krb5_cc_resolve(context, cc_name, &ccache))) {
381 printerr(0, "ERROR: %s while opening credential cache '%s'\n",
382 error_message(code), cc_name);
385 if ((code = krb5_cc_initialize(context, ccache, ple->princ))) {
386 printerr(0, "ERROR: %s while initializing credential "
387 "cache '%s'\n", error_message(code), cc_name);
390 if ((code = krb5_cc_store_cred(context, ccache, &my_creds))) {
391 printerr(0, "ERROR: %s while storing credentials in '%s'\n",
392 error_message(code), cc_name);
397 printerr(1, "Using (machine) credentials cache: '%s'\n", cc_name);
400 krb5_cc_close(context, ccache);
401 krb5_free_cred_contents(context, &my_creds);
406 * Determine if we already have a ple for the given realm
409 * 0 => no ple found for given realm
410 * 1 => found ple for given realm
413 gssd_have_realm_ple(krb5_data *realm)
415 struct gssd_k5_kt_princ *ple;
417 for (ple = gssd_k5_kt_princ_list; ple; ple = ple->next) {
418 if ((realm->length == strlen(ple->realm)) &&
419 (strncmp(realm->data, ple->realm, realm->length) == 0)) {
427 * Process the given keytab file and create a list of principals we
428 * might use to perform mount operations.
435 gssd_process_krb5_keytab(krb5_context context, krb5_keytab kt, char *kt_name)
437 krb5_kt_cursor cursor;
438 krb5_keytab_entry kte;
439 krb5_error_code code;
440 struct gssd_k5_kt_princ *ple;
444 * Look through each entry in the keytab file and determine
445 * if we might want to use it later to do a mount. If so,
446 * save info in the global principal list
447 * (gssd_k5_kt_princ_list).
448 * Note: (ple == principal list entry)
450 if ((code = krb5_kt_start_seq_get(context, kt, &cursor))) {
451 printerr(0, "ERROR: %s while beginning keytab scan "
453 error_message(code), kt_name);
458 while ((code = krb5_kt_next_entry(context, kt, &kte, &cursor)) == 0) {
460 if ((code = krb5_unparse_name(context, kte.principal,
462 printerr(0, "WARNING: Skipping keytab entry because "
463 "we failed to unparse principal name: %s\n",
464 error_message(code));
467 printerr(2, "Processing keytab entry for principal '%s'\n",
469 if ( (kte.principal->data[0].length == GSSD_SERVICE_NAME_LEN) &&
470 (strncmp(kte.principal->data[0].data, GSSD_SERVICE_NAME,
471 GSSD_SERVICE_NAME_LEN) == 0) &&
472 (!gssd_have_realm_ple(&kte.principal->realm)) ) {
473 printerr(2, "We will use this entry (%s)\n", pname);
474 ple = malloc(sizeof(struct gssd_k5_kt_princ));
476 printerr(0, "ERROR: could not allocate storage "
477 "for principal list entry\n");
478 krb5_free_unparsed_name(context, pname);
482 /* These will be filled in later */
487 strndup(kte.principal->realm.data,
488 kte.principal->realm.length))
490 printerr(0, "ERROR: %s while copying realm to "
491 "principal list entry\n",
492 "not enough memory");
493 krb5_free_unparsed_name(context, pname);
497 if ((code = krb5_copy_principal(context,
498 kte.principal, &ple->princ))) {
499 printerr(0, "ERROR: %s while copying principal "
500 "to principal list entry\n",
501 error_message(code));
502 krb5_free_unparsed_name(context, pname);
506 if (gssd_k5_kt_princ_list == NULL)
507 gssd_k5_kt_princ_list = ple;
509 ple->next = gssd_k5_kt_princ_list;
510 gssd_k5_kt_princ_list = ple;
514 printerr(2, "We will NOT use this entry (%s)\n",
517 krb5_free_unparsed_name(context, pname);
520 if ((code = krb5_kt_end_seq_get(context, kt, &cursor))) {
521 printerr(0, "WARNING: %s while ending keytab scan for "
523 error_message(code), kt_name);
532 /*==========================*/
533 /*=== External routines ===*/
534 /*==========================*/
537 * Attempt to find the best match for a credentials cache file
538 * given only a UID. We really need more information, but we
539 * do the best we can.
545 gssd_setup_krb5_user_gss_ccache(uid_t uid, char *servername)
547 char buf[MAX_NETOBJ_SZ];
548 #ifdef HAVE_GSS_KRB5_CCACHE_NAME
553 printerr(2, "getting credentials for client with uid %u for "
554 "server %s\n", uid, servername);
555 memset(buf, 0, sizeof(buf));
556 if (gssd_find_existing_krb5_ccache(uid, &d)) {
557 snprintf(buf, sizeof(buf), "FILE:%s/%s",
558 GSSD_DEFAULT_CRED_DIR, d->d_name);
562 snprintf(buf, sizeof(buf), "FILE:%s/%s%u",
563 GSSD_DEFAULT_CRED_DIR,
564 GSSD_DEFAULT_CRED_PREFIX, uid);
565 printerr(2, "using %s as credentials cache for client with "
566 "uid %u for server %s\n", buf, uid, servername);
567 #ifdef HAVE_GSS_KRB5_CCACHE_NAME
568 gss_krb5_ccache_name(&min_stat, buf, NULL);
571 * Set the KRB5CCNAME environment variable to tell the krb5 code
572 * which credentials cache to use. (Instead of using the private
573 * function above for which there is no generic gssapi
576 setenv("KRB5CCNAME", buf, 1);
581 * Let the gss code know where to find the machine credentials ccache.
587 gssd_setup_krb5_machine_gss_ccache(char *ccname)
589 #ifdef HAVE_GSS_KRB5_CCACHE_NAME
592 printerr(2, "using %s as credentials cache for machine creds\n",
594 #ifdef HAVE_GSS_KRB5_CCACHE_NAME
595 gss_krb5_ccache_name(&min_stat, ccname, NULL);
598 * Set the KRB5CCNAME environment variable to tell the krb5 code
599 * which credentials cache to use. (Instead of using the private
600 * function above for which there is no generic gssapi
603 setenv("KRB5CCNAME", ccname, 1);
608 * The first time through this routine, go through the keytab and
609 * determine which keys we will try to use as machine credentials.
610 * Every time through this routine, try to obtain credentials using
611 * the keytab entries selected the first time through.
614 * 0 => obtained one or more credentials
620 gssd_refresh_krb5_machine_creds(void)
622 krb5_context context = NULL;
623 krb5_keytab kt = NULL;;
624 krb5_error_code code;
626 struct gssd_k5_kt_princ *ple;
628 static int processed_keytab = 0;
631 code = krb5_init_context(&context);
633 printerr(0, "ERROR: %s while initializing krb5 in "
634 "gssd_refresh_krb5_machine_creds\n",
635 error_message(code));
640 printerr(1, "Using keytab file '%s'\n", keytabfile);
642 if ((code = krb5_kt_resolve(context, keytabfile, &kt))) {
643 printerr(0, "ERROR: %s while resolving keytab '%s'\n",
644 error_message(code), keytabfile);
648 /* Only go through the keytab file once. Only print messages once. */
649 if (gssd_k5_kt_princ_list == NULL && !processed_keytab) {
650 processed_keytab = 1;
651 gssd_process_krb5_keytab(context, kt, keytabfile);
652 if (gssd_k5_kt_princ_list == NULL) {
653 printerr(0, "ERROR: No usable keytab entries found in "
654 "keytab '%s'\n", keytabfile);
655 printerr(0, "Do you have a valid keytab entry for "
656 "%s/<your.host>@<YOUR.REALM> in "
657 "keytab file %s ?\n",
658 GSSD_SERVICE_NAME, keytabfile);
659 printerr(0, "Continuing without (machine) credentials "
660 "- nfs4 mounts with Kerberos will fail\n");
665 * If we don't have any keytab entries we liked, then we have a problem
667 if (gssd_k5_kt_princ_list == NULL) {
673 * Now go through the list of saved entries and get initial
674 * credentials for them (We can't do this while making the
675 * list because it messes up the keytab iteration cursor
676 * when we use the keytab to get credentials.)
678 for (ple = gssd_k5_kt_princ_list; ple; ple = ple->next) {
679 if ((gssd_get_single_krb5_cred(context, kt, ple)) == 0) {
684 printerr(0, "ERROR: No usable machine credentials obtained\n");
690 if (kt) krb5_kt_close(context, kt);
691 krb5_free_context(context);
698 * Return an array of pointers to names of credential cache files
699 * which can be used to try to create gss contexts with a server.
702 * 0 => list is attached
706 gssd_get_krb5_machine_cred_list(char ***list)
710 int listsize = listinc;
713 struct gssd_k5_kt_princ *ple;
717 *list = (char **) NULL;
719 /* Refresh machine credentials */
720 if ((retval = gssd_refresh_krb5_machine_creds())) {
724 if ((l = (char **) malloc(listsize * sizeof(char *))) == NULL) {
729 for (ple = gssd_k5_kt_princ_list; ple; ple = ple->next) {
731 if (i + 1 > listsize) {
734 realloc(l, listsize * sizeof(char *));
740 if ((l[i++] = strdup(ple->ccname)) == NULL) {
757 * Frees the list of names returned in get_krb5_machine_cred_list()
760 gssd_free_krb5_machine_cred_list(char **list)
766 for (n = list; n && *n; n++) {
773 * Called upon exit. Destroys machine credentials.
776 gssd_destroy_krb5_machine_creds(void)
778 krb5_context context;
779 krb5_error_code code = 0;
781 struct gssd_k5_kt_princ *ple;
783 code = krb5_init_context(&context);
785 printerr(0, "ERROR: %s while initializing krb5\n",
786 error_message(code));
790 for (ple = gssd_k5_kt_princ_list; ple; ple = ple->next) {
793 if ((code = krb5_cc_resolve(context, ple->ccname, &ccache))) {
794 printerr(0, "WARNING: %s while resolving credential "
795 "cache '%s' for destruction\n",
796 error_message(code), ple->ccname);
800 if ((code = krb5_cc_destroy(context, ccache))) {
801 printerr(0, "WARNING: %s while destroying credential "
803 error_message(code), ple->ccname);
807 krb5_free_context(context);