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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - security/keys/permission.c
1 /* Key permission checking
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/export.h>
13 #include <linux/security.h>
17 * key_task_permission - Check a key can be used
18 * @key_ref: The key to check.
19 * @cred: The credentials to use.
20 * @perm: The permissions to check for.
22 * Check to see whether permission is granted to use a key in the desired way,
23 * but permit the security modules to override.
25 * The caller must hold either a ref on cred or must hold the RCU readlock.
27 * Returns 0 if successful, -EACCES if access is denied based on the
28 * permissions bits or the LSM check.
30 int key_task_permission(const key_ref_t key_ref
, const struct cred
*cred
,
37 key
= key_ref_to_ptr(key_ref
);
39 /* use the second 8-bits of permissions for keys the caller owns */
40 if (uid_eq(key
->uid
, cred
->fsuid
)) {
41 kperm
= key
->perm
>> 16;
45 /* use the third 8-bits of permissions for keys the caller has a group
46 * membership in common with */
47 if (gid_valid(key
->gid
) && key
->perm
& KEY_GRP_ALL
) {
48 if (gid_eq(key
->gid
, cred
->fsgid
)) {
49 kperm
= key
->perm
>> 8;
53 ret
= groups_search(cred
->group_info
, key
->gid
);
55 kperm
= key
->perm
>> 8;
60 /* otherwise use the least-significant 8-bits */
65 /* use the top 8-bits of permissions for keys the caller possesses
66 * - possessor permissions are additive with other permissions
68 if (is_key_possessed(key_ref
))
69 kperm
|= key
->perm
>> 24;
71 kperm
= kperm
& perm
& KEY_NEED_ALL
;
76 /* let LSM be the final arbiter */
77 return security_key_permission(key_ref
, cred
, perm
);
79 EXPORT_SYMBOL(key_task_permission
);
82 * key_validate - Validate a key.
83 * @key: The key to be validated.
85 * Check that a key is valid, returning 0 if the key is okay, -ENOKEY if the
86 * key is invalidated, -EKEYREVOKED if the key's type has been removed or if
87 * the key has been revoked or -EKEYEXPIRED if the key has expired.
89 int key_validate(const struct key
*key
)
91 unsigned long flags
= READ_ONCE(key
->flags
);
92 time64_t expiry
= READ_ONCE(key
->expiry
);
94 if (flags
& (1 << KEY_FLAG_INVALIDATED
))
97 /* check it's still accessible */
98 if (flags
& ((1 << KEY_FLAG_REVOKED
) |
99 (1 << KEY_FLAG_DEAD
)))
102 /* check it hasn't expired */
104 if (ktime_get_real_seconds() >= expiry
)
110 EXPORT_SYMBOL(key_validate
);