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
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
/* request_key_auth.c: request key authorisation controlling key def
*
* 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.
*
* See Documentation/keys-request-key.txt
*/
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <linux/seq_file.h>
#include "internal.h"
static int request_key_auth_instantiate(struct key *, const void *, size_t);
static void request_key_auth_describe(const struct key *, struct seq_file *);
static void request_key_auth_destroy(struct key *);
/*
* the request-key authorisation key type definition
*/
struct key_type key_type_request_key_auth = {
.name = ".request_key_auth",
.def_datalen = sizeof(struct request_key_auth),
.instantiate = request_key_auth_instantiate,
.describe = request_key_auth_describe,
.destroy = request_key_auth_destroy,
};
/*****************************************************************************/
/*
* instantiate a request-key authorisation record
*/
static int request_key_auth_instantiate(struct key *key,
const void *data,
size_t datalen)
{
struct request_key_auth *rka, *irka;
struct key *instkey;
int ret;
ret = -ENOMEM;
rka = kmalloc(sizeof(*rka), GFP_KERNEL);
if (rka) {
/* see if the calling process is already servicing the key
* request of another process */
instkey = key_get_instantiation_authkey(0);
if (!IS_ERR(instkey)) {
/* it is - use that instantiation context here too */
irka = instkey->payload.data;
rka->context = irka->context;
rka->pid = irka->pid;
key_put(instkey);
}
else {
/* it isn't - use this process as the context */
rka->context = current;
rka->pid = current->pid;
}
rka->target_key = key_get((struct key *) data);
key->payload.data = rka;
ret = 0;
}
return ret;
} /* end request_key_auth_instantiate() */
/*****************************************************************************/
/*
*
*/
static void request_key_auth_describe(const struct key *key,
struct seq_file *m)
{
struct request_key_auth *rka = key->payload.data;
seq_puts(m, "key:");
seq_puts(m, key->description);
seq_printf(m, " pid:%d", rka->pid);
} /* end request_key_auth_describe() */
/*****************************************************************************/
/*
* destroy an instantiation authorisation token key
*/
static void request_key_auth_destroy(struct key *key)
{
struct request_key_auth *rka = key->payload.data;
kenter("{%d}", key->serial);
key_put(rka->target_key);
kfree(rka);
} /* end request_key_auth_destroy() */
/*****************************************************************************/
/*
* create a session keyring to be for the invokation of /sbin/request-key and
* stick an authorisation token in it
*/
struct key *request_key_auth_new(struct key *target, struct key **_rkakey)
{
struct key *keyring, *rkakey = NULL;
char desc[20];
int ret;
kenter("%d,", target->serial);
/* allocate a new session keyring */
sprintf(desc, "_req.%u", target->serial);
keyring = keyring_alloc(desc, current->fsuid, current->fsgid, 1, NULL);
if (IS_ERR(keyring)) {
kleave("= %ld", PTR_ERR(keyring));
return keyring;
}
/* allocate the auth key */
sprintf(desc, "%x", target->serial);
rkakey = key_alloc(&key_type_request_key_auth, desc,
current->fsuid, current->fsgid,
KEY_POS_VIEW | KEY_USR_VIEW, 1);
if (IS_ERR(rkakey)) {
key_put(keyring);
kleave("= %ld", PTR_ERR(rkakey));
return rkakey;
}
/* construct and attach to the keyring */
ret = key_instantiate_and_link(rkakey, target, 0, keyring, NULL);
if (ret < 0) {
key_revoke(rkakey);
key_put(rkakey);
key_put(keyring);
kleave("= %d", ret);
return ERR_PTR(ret);
}
*_rkakey = rkakey;
kleave(" = {%d} ({%d})", keyring->serial, rkakey->serial);
return keyring;
} /* end request_key_auth_new() */
/*****************************************************************************/
/*
* get the authorisation key for instantiation of a specific key if attached to
* the current process's keyrings
* - this key is inserted into a keyring and that is set as /sbin/request-key's
* session keyring
* - a target_id of zero specifies any valid token
*/
struct key *key_get_instantiation_authkey(key_serial_t target_id)
{
struct task_struct *tsk = current;
struct key *instkey;
/* we must have our own personal session keyring */
if (!tsk->signal->session_keyring)
return ERR_PTR(-EACCES);
/* and it must contain a suitable request authorisation key
* - lock RCU against session keyring changing
*/
rcu_read_lock();
instkey = keyring_search_instkey(
rcu_dereference(tsk->signal->session_keyring), target_id);
rcu_read_unlock();
return instkey;
} /* end key_get_instantiation_authkey() */
|