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 .preparse = user_preparse,
31 .free_preparse = user_free_preparse,
32 .instantiate = generic_key_instantiate,
33 .update = user_update,
35 .revoke = user_revoke,
36 .destroy = user_destroy,
37 .describe = user_describe,
41 EXPORT_SYMBOL_GPL(key_type_user);
44 * This key type is essentially the same as key_type_user, but it does
45 * not define a .read op. This is suitable for storing username and
46 * password pairs in the keyring that you do not want to be readable
49 struct key_type key_type_logon = {
51 .def_lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT,
52 .preparse = user_preparse,
53 .free_preparse = user_free_preparse,
54 .instantiate = generic_key_instantiate,
55 .update = user_update,
57 .revoke = user_revoke,
58 .destroy = user_destroy,
59 .describe = user_describe,
60 .vet_description = logon_vet_description,
62 EXPORT_SYMBOL_GPL(key_type_logon);
65 * Preparse a user defined key payload
67 int user_preparse(struct key_preparsed_payload *prep)
69 struct user_key_payload *upayload;
70 size_t datalen = prep->datalen;
72 if (datalen <= 0 || datalen > 32767 || !prep->data)
75 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
80 prep->quotalen = datalen;
81 prep->payload[0] = upayload;
82 upayload->datalen = datalen;
83 memcpy(upayload->data, prep->data, datalen);
86 EXPORT_SYMBOL_GPL(user_preparse);
89 * Free a preparse of a user defined key payload
91 void user_free_preparse(struct key_preparsed_payload *prep)
93 kfree(prep->payload[0]);
95 EXPORT_SYMBOL_GPL(user_free_preparse);
98 * update a user defined key
99 * - the key's semaphore is write-locked
101 int user_update(struct key *key, struct key_preparsed_payload *prep)
103 struct user_key_payload *upayload, *zap;
104 size_t datalen = prep->datalen;
108 if (datalen <= 0 || datalen > 32767 || !prep->data)
111 /* construct a replacement payload */
113 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
117 upayload->datalen = datalen;
118 memcpy(upayload->data, prep->data, datalen);
120 /* check the quota and attach the new data */
123 ret = key_payload_reserve(key, datalen);
126 /* attach the new data, displacing the old */
127 zap = key->payload.data;
128 rcu_assign_keypointer(key, upayload);
139 EXPORT_SYMBOL_GPL(user_update);
142 * match users on their name
144 int user_match(const struct key *key, const void *description)
146 return strcmp(key->description, description) == 0;
149 EXPORT_SYMBOL_GPL(user_match);
152 * dispose of the links from a revoked keyring
153 * - called with the key sem write-locked
155 void user_revoke(struct key *key)
157 struct user_key_payload *upayload = key->payload.data;
159 /* clear the quota */
160 key_payload_reserve(key, 0);
163 rcu_assign_keypointer(key, NULL);
164 kfree_rcu(upayload, rcu);
168 EXPORT_SYMBOL(user_revoke);
171 * dispose of the data dangling from the corpse of a user key
173 void user_destroy(struct key *key)
175 struct user_key_payload *upayload = key->payload.data;
180 EXPORT_SYMBOL_GPL(user_destroy);
183 * describe the user key
185 void user_describe(const struct key *key, struct seq_file *m)
187 seq_puts(m, key->description);
188 if (key_is_instantiated(key))
189 seq_printf(m, ": %u", key->datalen);
192 EXPORT_SYMBOL_GPL(user_describe);
196 * - the key's semaphore is read-locked
198 long user_read(const struct key *key, char __user *buffer, size_t buflen)
200 struct user_key_payload *upayload;
203 upayload = rcu_dereference_key(key);
204 ret = upayload->datalen;
206 /* we can return the data as is */
207 if (buffer && buflen > 0) {
208 if (buflen > upayload->datalen)
209 buflen = upayload->datalen;
211 if (copy_to_user(buffer, upayload->data, buflen) != 0)
218 EXPORT_SYMBOL_GPL(user_read);
220 /* Vet the description for a "logon" key */
221 static int logon_vet_description(const char *desc)
225 /* require a "qualified" description string */
226 p = strchr(desc, ':');
230 /* also reject description with ':' as first char */