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
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
|
/* General persistent per-UID keyrings register
*
* Copyright (C) 2013 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 Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/user_namespace.h>
#include "internal.h"
unsigned persistent_keyring_expiry = 3 * 24 * 3600; /* Expire after 3 days of non-use */
/*
* Create the persistent keyring register for the current user namespace.
*
* Called with the namespace's sem locked for writing.
*/
static int key_create_persistent_register(struct user_namespace *ns)
{
struct key *reg = keyring_alloc(".persistent_register",
KUIDT_INIT(0), KGIDT_INIT(0),
current_cred(),
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ),
KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
if (IS_ERR(reg))
return PTR_ERR(reg);
ns->persistent_keyring_register = reg;
return 0;
}
/*
* Create the persistent keyring for the specified user.
*
* Called with the namespace's sem locked for writing.
*/
static key_ref_t key_create_persistent(struct user_namespace *ns, kuid_t uid,
struct keyring_index_key *index_key)
{
struct key *persistent;
key_ref_t reg_ref, persistent_ref;
if (!ns->persistent_keyring_register) {
long err = key_create_persistent_register(ns);
if (err < 0)
return ERR_PTR(err);
} else {
reg_ref = make_key_ref(ns->persistent_keyring_register, true);
persistent_ref = find_key_to_update(reg_ref, index_key);
if (persistent_ref)
return persistent_ref;
}
persistent = keyring_alloc(index_key->description,
uid, INVALID_GID, current_cred(),
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ),
KEY_ALLOC_NOT_IN_QUOTA, NULL,
ns->persistent_keyring_register);
if (IS_ERR(persistent))
return ERR_CAST(persistent);
return make_key_ref(persistent, true);
}
/*
* Get the persistent keyring for a specific UID and link it to the nominated
* keyring.
*/
static long key_get_persistent(struct user_namespace *ns, kuid_t uid,
key_ref_t dest_ref)
{
struct keyring_index_key index_key;
struct key *persistent;
key_ref_t reg_ref, persistent_ref;
char buf[32];
long ret;
/* Look in the register if it exists */
index_key.type = &key_type_keyring;
index_key.description = buf;
index_key.desc_len = sprintf(buf, "_persistent.%u", from_kuid(ns, uid));
if (ns->persistent_keyring_register) {
reg_ref = make_key_ref(ns->persistent_keyring_register, true);
down_read(&ns->persistent_keyring_register_sem);
persistent_ref = find_key_to_update(reg_ref, &index_key);
up_read(&ns->persistent_keyring_register_sem);
if (persistent_ref)
goto found;
}
/* It wasn't in the register, so we'll need to create it. We might
* also need to create the register.
*/
down_write(&ns->persistent_keyring_register_sem);
persistent_ref = key_create_persistent(ns, uid, &index_key);
up_write(&ns->persistent_keyring_register_sem);
if (!IS_ERR(persistent_ref))
goto found;
return PTR_ERR(persistent_ref);
found:
ret = key_task_permission(persistent_ref, current_cred(), KEY_NEED_LINK);
if (ret == 0) {
persistent = key_ref_to_ptr(persistent_ref);
ret = key_link(key_ref_to_ptr(dest_ref), persistent);
if (ret == 0) {
key_set_timeout(persistent, persistent_keyring_expiry);
ret = persistent->serial;
}
}
key_ref_put(persistent_ref);
return ret;
}
/*
* Get the persistent keyring for a specific UID and link it to the nominated
* keyring.
*/
long keyctl_get_persistent(uid_t _uid, key_serial_t destid)
{
struct user_namespace *ns = current_user_ns();
key_ref_t dest_ref;
kuid_t uid;
long ret;
/* -1 indicates the current user */
if (_uid == (uid_t)-1) {
uid = current_uid();
} else {
uid = make_kuid(ns, _uid);
if (!uid_valid(uid))
return -EINVAL;
/* You can only see your own persistent cache if you're not
* sufficiently privileged.
*/
if (!uid_eq(uid, current_uid()) &&
!uid_eq(uid, current_euid()) &&
!ns_capable(ns, CAP_SETUID))
return -EPERM;
}
/* There must be a destination keyring */
dest_ref = lookup_user_key(destid, KEY_LOOKUP_CREATE, KEY_NEED_WRITE);
if (IS_ERR(dest_ref))
return PTR_ERR(dest_ref);
if (key_ref_to_ptr(dest_ref)->type != &key_type_keyring) {
ret = -ENOTDIR;
goto out_put_dest;
}
ret = key_get_persistent(ns, uid, dest_ref);
out_put_dest:
key_ref_put(dest_ref);
return ret;
}
|
