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 */