blob: baf3d5f31e7136c6a92f5cd73d947accc6308530 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
/* permission.c: key permission determination
*
* Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/security.h>
#include "internal.h"
/*****************************************************************************/
/*
* check to see whether permission is granted to use a key in the desired way,
* but permit the security modules to override
*/
int key_task_permission(const key_ref_t key_ref,
struct task_struct *context,
key_perm_t perm)
{
struct cred *cred = context->cred;
struct key *key;
key_perm_t kperm;
int ret;
key = key_ref_to_ptr(key_ref);
/* use the second 8-bits of permissions for keys the caller owns */
if (key->uid == cred->fsuid) {
kperm = key->perm >> 16;
goto use_these_perms;
}
/* use the third 8-bits of permissions for keys the caller has a group
* membership in common with */
if (key->gid != -1 && key->perm & KEY_GRP_ALL) {
if (key->gid == cred->fsgid) {
kperm = key->perm >> 8;
goto use_these_perms;
}
spin_lock(&cred->lock);
ret = groups_search(cred->group_info, key->gid);
spin_unlock(&cred->lock);
if (ret) {
kperm = key->perm >> 8;
goto use_these_perms;
}
}
/* otherwise use the least-significant 8-bits */
kperm = key->perm;
use_these_perms:
/* use the top 8-bits of permissions for keys the caller possesses
* - possessor permissions are additive with other permissions
*/
if (is_key_possessed(key_ref))
kperm |= key->perm >> 24;
kperm = kperm & perm & KEY_ALL;
if (kperm != perm)
return -EACCES;
/* let LSM be the final arbiter */
return security_key_permission(key_ref, context, perm);
} /* end key_task_permission() */
EXPORT_SYMBOL(key_task_permission);
/*****************************************************************************/
/*
* validate a key
*/
int key_validate(struct key *key)
{
struct timespec now;
int ret = 0;
if (key) {
/* check it's still accessible */
ret = -EKEYREVOKED;
if (test_bit(KEY_FLAG_REVOKED, &key->flags) ||
test_bit(KEY_FLAG_DEAD, &key->flags))
goto error;
/* check it hasn't expired */
ret = 0;
if (key->expiry) {
now = current_kernel_time();
if (now.tv_sec >= key->expiry)
ret = -EKEYEXPIRED;
}
}
error:
return ret;
} /* end key_validate() */
EXPORT_SYMBOL(key_validate);
|
