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>
13 #include <linux/security.h>
16 /*****************************************************************************/
18 * check to see whether permission is granted to use a key in the desired way,
19 * but permit the security modules to override
21 int key_task_permission(const key_ref_t key_ref,
22 struct task_struct *context,
25 const struct cred *cred;
30 key = key_ref_to_ptr(key_ref);
33 cred = __task_cred(context);
35 /* use the second 8-bits of permissions for keys the caller owns */
36 if (key->uid == cred->fsuid) {
37 kperm = key->perm >> 16;
41 /* use the third 8-bits of permissions for keys the caller has a group
42 * membership in common with */
43 if (key->gid != -1 && key->perm & KEY_GRP_ALL) {
44 if (key->gid == cred->fsgid) {
45 kperm = key->perm >> 8;
49 ret = groups_search(cred->group_info, key->gid);
51 kperm = key->perm >> 8;
56 /* otherwise use the least-significant 8-bits */
62 /* use the top 8-bits of permissions for keys the caller possesses
63 * - possessor permissions are additive with other permissions
65 if (is_key_possessed(key_ref))
66 kperm |= key->perm >> 24;
68 kperm = kperm & perm & KEY_ALL;
73 /* let LSM be the final arbiter */
74 return security_key_permission(key_ref, context, perm);
76 } /* end key_task_permission() */
78 EXPORT_SYMBOL(key_task_permission);
80 /*****************************************************************************/
84 int key_validate(struct key *key)
90 /* check it's still accessible */
92 if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
93 test_bit(KEY_FLAG_DEAD, &key->flags))
96 /* check it hasn't expired */
99 now = current_kernel_time();
100 if (now.tv_sec >= key->expiry)
108 } /* end key_validate() */
110 EXPORT_SYMBOL(key_validate);