1 /*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21
22 /*
23 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
24 * Use is subject to license terms.
25 */
26
27 #include <sys/types.h>
28 #include <unistd.h>
29 #include <dlfcn.h>
30 #include "k5-int.h"
31
32 #define KRB5_UID "app_krb5_user_uid"
33
34 /*
35 * mech_krb5 makes various calls to getuid(). When employed by gssd(8) and
36 * ktkt_warnd(8), app_krb5_user_uid() is used to select a given user's
37 * credential cache, rather than the id of the process.
38 */
39 uid_t
krb5_getuid()40 krb5_getuid()
41 {
42 static uid_t (*gptr)() = NULL;
43 void *handle;
44
45 if (gptr == NULL) {
46 /*
47 * Specifically look for app_krb5_user_uid() in the application,
48 * and don't fall into an exhaustive search through all of the
49 * process dependencies. This interface is suplied from
50 * gssd(8) and ktkt_warnd(8).
51 */
52 if (((handle = dlopen(0, (RTLD_LAZY | RTLD_FIRST))) == NULL) ||
53 ((gptr = (uid_t (*)())dlsym(handle, KRB5_UID)) == NULL)) {
54 /*
55 * Fall back to the default getuid(), which is probably
56 * libc.
57 */
58 gptr = &getuid;
59 }
60 }
61
62 /*
63 * Return the appropriate uid. Note, if a default getuid() couldn't
64 * be found, the getuid assignment would have failed to relocate, and
65 * hence this module would fail to load.
66 */
67 return ((*gptr)());
68 }
69