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 .instantiate = user_instantiate,
30 .update = user_update,
32 .revoke = user_revoke,
33 .destroy = user_destroy,
34 .describe = user_describe,
38 EXPORT_SYMBOL_GPL(key_type_user);
41 * This key type is essentially the same as key_type_user, but it does
42 * not define a .read op. This is suitable for storing username and
43 * password pairs in the keyring that you do not want to be readable
46 struct key_type key_type_logon = {
48 .instantiate = user_instantiate,
49 .update = user_update,
51 .revoke = user_revoke,
52 .destroy = user_destroy,
53 .describe = user_describe,
54 .vet_description = logon_vet_description,
56 EXPORT_SYMBOL_GPL(key_type_logon);
59 * instantiate a user defined key
61 int user_instantiate(struct key *key, const void *data, size_t datalen)
63 struct user_key_payload *upayload;
67 if (datalen <= 0 || datalen > 32767 || !data)
70 ret = key_payload_reserve(key, datalen);
75 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
80 upayload->datalen = datalen;
81 memcpy(upayload->data, data, datalen);
82 rcu_assign_keypointer(key, upayload);
89 EXPORT_SYMBOL_GPL(user_instantiate);
92 * update a user defined key
93 * - the key's semaphore is write-locked
95 int user_update(struct key *key, const void *data, size_t datalen)
97 struct user_key_payload *upayload, *zap;
101 if (datalen <= 0 || datalen > 32767 || !data)
104 /* construct a replacement payload */
106 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
110 upayload->datalen = datalen;
111 memcpy(upayload->data, data, datalen);
113 /* check the quota and attach the new data */
116 ret = key_payload_reserve(key, datalen);
119 /* attach the new data, displacing the old */
120 zap = key->payload.data;
121 rcu_assign_keypointer(key, upayload);
132 EXPORT_SYMBOL_GPL(user_update);
135 * match users on their name
137 int user_match(const struct key *key, const void *description)
139 return strcmp(key->description, description) == 0;
142 EXPORT_SYMBOL_GPL(user_match);
145 * dispose of the links from a revoked keyring
146 * - called with the key sem write-locked
148 void user_revoke(struct key *key)
150 struct user_key_payload *upayload = key->payload.data;
152 /* clear the quota */
153 key_payload_reserve(key, 0);
156 rcu_assign_keypointer(key, NULL);
157 kfree_rcu(upayload, rcu);
161 EXPORT_SYMBOL(user_revoke);
164 * dispose of the data dangling from the corpse of a user key
166 void user_destroy(struct key *key)
168 struct user_key_payload *upayload = key->payload.data;
173 EXPORT_SYMBOL_GPL(user_destroy);
176 * describe the user key
178 void user_describe(const struct key *key, struct seq_file *m)
180 seq_puts(m, key->description);
181 if (key_is_instantiated(key))
182 seq_printf(m, ": %u", key->datalen);
185 EXPORT_SYMBOL_GPL(user_describe);
189 * - the key's semaphore is read-locked
191 long user_read(const struct key *key, char __user *buffer, size_t buflen)
193 struct user_key_payload *upayload;
196 upayload = rcu_dereference_key(key);
197 ret = upayload->datalen;
199 /* we can return the data as is */
200 if (buffer && buflen > 0) {
201 if (buflen > upayload->datalen)
202 buflen = upayload->datalen;
204 if (copy_to_user(buffer, upayload->data, buflen) != 0)
211 EXPORT_SYMBOL_GPL(user_read);
213 /* Vet the description for a "logon" key */
214 static int logon_vet_description(const char *desc)
218 /* require a "qualified" description string */
219 p = strchr(desc, ':');
223 /* also reject description with ':' as first char */