1 /* user_defined.c: user defined key type
3 * Copyright (C) 2004 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/init.h>
14 #include <linux/slab.h>
15 #include <linux/seq_file.h>
16 #include <linux/err.h>
17 #include <keys/user-type.h>
18 #include <asm/uaccess.h>
21 static int logon_vet_description(const char *desc
);
24 * user defined keys take an arbitrary string as the description and an
25 * arbitrary blob of data as the payload
27 struct key_type key_type_user
= {
29 .def_lookup_type
= KEYRING_SEARCH_LOOKUP_DIRECT
,
30 .instantiate
= user_instantiate
,
31 .update
= user_update
,
33 .revoke
= user_revoke
,
34 .destroy
= user_destroy
,
35 .describe
= user_describe
,
39 EXPORT_SYMBOL_GPL(key_type_user
);
42 * This key type is essentially the same as key_type_user, but it does
43 * not define a .read op. This is suitable for storing username and
44 * password pairs in the keyring that you do not want to be readable
47 struct key_type key_type_logon
= {
49 .def_lookup_type
= KEYRING_SEARCH_LOOKUP_DIRECT
,
50 .instantiate
= user_instantiate
,
51 .update
= user_update
,
53 .revoke
= user_revoke
,
54 .destroy
= user_destroy
,
55 .describe
= user_describe
,
56 .vet_description
= logon_vet_description
,
58 EXPORT_SYMBOL_GPL(key_type_logon
);
61 * instantiate a user defined key
63 int user_instantiate(struct key
*key
, struct key_preparsed_payload
*prep
)
65 struct user_key_payload
*upayload
;
66 size_t datalen
= prep
->datalen
;
70 if (datalen
<= 0 || datalen
> 32767 || !prep
->data
)
73 ret
= key_payload_reserve(key
, datalen
);
78 upayload
= kmalloc(sizeof(*upayload
) + datalen
, GFP_KERNEL
);
83 upayload
->datalen
= datalen
;
84 memcpy(upayload
->data
, prep
->data
, datalen
);
85 rcu_assign_keypointer(key
, upayload
);
92 EXPORT_SYMBOL_GPL(user_instantiate
);
95 * update a user defined key
96 * - the key's semaphore is write-locked
98 int user_update(struct key
*key
, struct key_preparsed_payload
*prep
)
100 struct user_key_payload
*upayload
, *zap
;
101 size_t datalen
= prep
->datalen
;
105 if (datalen
<= 0 || datalen
> 32767 || !prep
->data
)
108 /* construct a replacement payload */
110 upayload
= kmalloc(sizeof(*upayload
) + datalen
, GFP_KERNEL
);
114 upayload
->datalen
= datalen
;
115 memcpy(upayload
->data
, prep
->data
, datalen
);
117 /* check the quota and attach the new data */
120 ret
= key_payload_reserve(key
, datalen
);
123 /* attach the new data, displacing the old */
124 zap
= key
->payload
.data
;
125 rcu_assign_keypointer(key
, upayload
);
136 EXPORT_SYMBOL_GPL(user_update
);
139 * match users on their name
141 int user_match(const struct key
*key
, const void *description
)
143 return strcmp(key
->description
, description
) == 0;
146 EXPORT_SYMBOL_GPL(user_match
);
149 * dispose of the links from a revoked keyring
150 * - called with the key sem write-locked
152 void user_revoke(struct key
*key
)
154 struct user_key_payload
*upayload
= key
->payload
.data
;
156 /* clear the quota */
157 key_payload_reserve(key
, 0);
160 rcu_assign_keypointer(key
, NULL
);
161 kfree_rcu(upayload
, rcu
);
165 EXPORT_SYMBOL(user_revoke
);
168 * dispose of the data dangling from the corpse of a user key
170 void user_destroy(struct key
*key
)
172 struct user_key_payload
*upayload
= key
->payload
.data
;
177 EXPORT_SYMBOL_GPL(user_destroy
);
180 * describe the user key
182 void user_describe(const struct key
*key
, struct seq_file
*m
)
184 seq_puts(m
, key
->description
);
185 if (key_is_instantiated(key
))
186 seq_printf(m
, ": %u", key
->datalen
);
189 EXPORT_SYMBOL_GPL(user_describe
);
193 * - the key's semaphore is read-locked
195 long user_read(const struct key
*key
, char __user
*buffer
, size_t buflen
)
197 struct user_key_payload
*upayload
;
200 upayload
= rcu_dereference_key(key
);
201 ret
= upayload
->datalen
;
203 /* we can return the data as is */
204 if (buffer
&& buflen
> 0) {
205 if (buflen
> upayload
->datalen
)
206 buflen
= upayload
->datalen
;
208 if (copy_to_user(buffer
, upayload
->data
, buflen
) != 0)
215 EXPORT_SYMBOL_GPL(user_read
);
217 /* Vet the description for a "logon" key */
218 static int logon_vet_description(const char *desc
)
222 /* require a "qualified" description string */
223 p
= strchr(desc
, ':');
227 /* also reject description with ':' as first char */