USB: serial: mos7720: fix non-atomic allocation in write path
[linux/fpc-iii.git] / security / keys / user_defined.c
blob66b1840b4110b6ee876af85c8ba598a3054a43f8
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>
19 #include "internal.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 = {
28 .name = "user",
29 .preparse = user_preparse,
30 .free_preparse = user_free_preparse,
31 .instantiate = generic_key_instantiate,
32 .update = user_update,
33 .revoke = user_revoke,
34 .destroy = user_destroy,
35 .describe = user_describe,
36 .read = user_read,
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
45 * from userspace.
47 struct key_type key_type_logon = {
48 .name = "logon",
49 .preparse = user_preparse,
50 .free_preparse = user_free_preparse,
51 .instantiate = generic_key_instantiate,
52 .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 * Preparse a user defined key payload
63 int user_preparse(struct key_preparsed_payload *prep)
65 struct user_key_payload *upayload;
66 size_t datalen = prep->datalen;
68 if (datalen <= 0 || datalen > 32767 || !prep->data)
69 return -EINVAL;
71 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
72 if (!upayload)
73 return -ENOMEM;
75 /* attach the data */
76 prep->quotalen = datalen;
77 prep->payload.data[0] = upayload;
78 upayload->datalen = datalen;
79 memcpy(upayload->data, prep->data, datalen);
80 return 0;
82 EXPORT_SYMBOL_GPL(user_preparse);
85 * Free a preparse of a user defined key payload
87 void user_free_preparse(struct key_preparsed_payload *prep)
89 kfree(prep->payload.data[0]);
91 EXPORT_SYMBOL_GPL(user_free_preparse);
94 * update a user defined key
95 * - the key's semaphore is write-locked
97 int user_update(struct key *key, struct key_preparsed_payload *prep)
99 struct user_key_payload *zap = NULL;
100 int ret;
102 /* check the quota and attach the new data */
103 ret = key_payload_reserve(key, prep->datalen);
104 if (ret < 0)
105 return ret;
107 /* attach the new data, displacing the old */
108 key->expiry = prep->expiry;
109 if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags))
110 zap = rcu_dereference_key(key);
111 rcu_assign_keypointer(key, prep->payload.data[0]);
112 prep->payload.data[0] = NULL;
114 if (zap)
115 kfree_rcu(zap, rcu);
116 return ret;
118 EXPORT_SYMBOL_GPL(user_update);
121 * dispose of the links from a revoked keyring
122 * - called with the key sem write-locked
124 void user_revoke(struct key *key)
126 struct user_key_payload *upayload = key->payload.data[0];
128 /* clear the quota */
129 key_payload_reserve(key, 0);
131 if (upayload) {
132 rcu_assign_keypointer(key, NULL);
133 kfree_rcu(upayload, rcu);
137 EXPORT_SYMBOL(user_revoke);
140 * dispose of the data dangling from the corpse of a user key
142 void user_destroy(struct key *key)
144 struct user_key_payload *upayload = key->payload.data[0];
146 kfree(upayload);
149 EXPORT_SYMBOL_GPL(user_destroy);
152 * describe the user key
154 void user_describe(const struct key *key, struct seq_file *m)
156 seq_puts(m, key->description);
157 if (key_is_instantiated(key))
158 seq_printf(m, ": %u", key->datalen);
161 EXPORT_SYMBOL_GPL(user_describe);
164 * read the key data
165 * - the key's semaphore is read-locked
167 long user_read(const struct key *key, char __user *buffer, size_t buflen)
169 const struct user_key_payload *upayload;
170 long ret;
172 upayload = user_key_payload(key);
173 ret = upayload->datalen;
175 /* we can return the data as is */
176 if (buffer && buflen > 0) {
177 if (buflen > upayload->datalen)
178 buflen = upayload->datalen;
180 if (copy_to_user(buffer, upayload->data, buflen) != 0)
181 ret = -EFAULT;
184 return ret;
187 EXPORT_SYMBOL_GPL(user_read);
189 /* Vet the description for a "logon" key */
190 static int logon_vet_description(const char *desc)
192 char *p;
194 /* require a "qualified" description string */
195 p = strchr(desc, ':');
196 if (!p)
197 return -EINVAL;
199 /* also reject description with ':' as first char */
200 if (p == desc)
201 return -EINVAL;
203 return 0;