1 /* permission.c: key permission determination
3 * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
12 #include <linux/module.h>
15 /*****************************************************************************/
17 * check to see whether permission is granted to use a key in the desired way,
18 * but permit the security modules to override
20 int key_task_permission(const key_ref_t key_ref,
21 struct task_struct *context,
28 key = key_ref_to_ptr(key_ref);
30 /* use the top 8-bits of permissions for keys the caller possesses */
31 if (is_key_possessed(key_ref)) {
32 kperm = key->perm >> 24;
36 /* use the second 8-bits of permissions for keys the caller owns */
37 if (key->uid == context->fsuid) {
38 kperm = key->perm >> 16;
42 /* use the third 8-bits of permissions for keys the caller has a group
43 * membership in common with */
44 if (key->gid != -1 && key->perm & KEY_GRP_ALL) {
45 if (key->gid == context->fsgid) {
46 kperm = key->perm >> 8;
51 ret = groups_search(context->group_info, key->gid);
55 kperm = key->perm >> 8;
60 /* otherwise use the least-significant 8-bits */
64 kperm = kperm & perm & KEY_ALL;
68 } /* end key_task_permission() */
70 EXPORT_SYMBOL(key_task_permission);