Commit | Line | Data |
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1da177e4 LT |
1 | /* user_defined.c: user defined key type |
2 | * | |
3 | * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. | |
4 | * Written by David Howells (dhowells@redhat.com) | |
5 | * | |
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. | |
10 | */ | |
11 | ||
12 | #include <linux/module.h> | |
13 | #include <linux/init.h> | |
1da177e4 LT |
14 | #include <linux/slab.h> |
15 | #include <linux/seq_file.h> | |
16 | #include <linux/err.h> | |
2aa349f6 | 17 | #include <keys/user-type.h> |
1da177e4 LT |
18 | #include <asm/uaccess.h> |
19 | #include "internal.h" | |
20 | ||
1da177e4 LT |
21 | /* |
22 | * user defined keys take an arbitrary string as the description and an | |
23 | * arbitrary blob of data as the payload | |
24 | */ | |
25 | struct key_type key_type_user = { | |
26 | .name = "user", | |
27 | .instantiate = user_instantiate, | |
1da177e4 LT |
28 | .update = user_update, |
29 | .match = user_match, | |
31204ed9 | 30 | .revoke = user_revoke, |
1da177e4 LT |
31 | .destroy = user_destroy, |
32 | .describe = user_describe, | |
33 | .read = user_read, | |
34 | }; | |
35 | ||
16c29b67 MH |
36 | EXPORT_SYMBOL_GPL(key_type_user); |
37 | ||
1da177e4 LT |
38 | /* |
39 | * instantiate a user defined key | |
40 | */ | |
2aa349f6 | 41 | int user_instantiate(struct key *key, const void *data, size_t datalen) |
1da177e4 | 42 | { |
76d8aeab | 43 | struct user_key_payload *upayload; |
1da177e4 LT |
44 | int ret; |
45 | ||
46 | ret = -EINVAL; | |
47 | if (datalen <= 0 || datalen > 32767 || !data) | |
48 | goto error; | |
49 | ||
50 | ret = key_payload_reserve(key, datalen); | |
51 | if (ret < 0) | |
52 | goto error; | |
53 | ||
1da177e4 | 54 | ret = -ENOMEM; |
76d8aeab DH |
55 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
56 | if (!upayload) | |
1da177e4 LT |
57 | goto error; |
58 | ||
76d8aeab DH |
59 | /* attach the data */ |
60 | upayload->datalen = datalen; | |
61 | memcpy(upayload->data, data, datalen); | |
62 | rcu_assign_pointer(key->payload.data, upayload); | |
1da177e4 LT |
63 | ret = 0; |
64 | ||
2aa349f6 | 65 | error: |
1da177e4 | 66 | return ret; |
a8b17ed0 | 67 | } |
31204ed9 | 68 | |
2aa349f6 DH |
69 | EXPORT_SYMBOL_GPL(user_instantiate); |
70 | ||
76d8aeab DH |
71 | /* |
72 | * dispose of the old data from an updated user defined key | |
73 | */ | |
74 | static void user_update_rcu_disposal(struct rcu_head *rcu) | |
75 | { | |
76 | struct user_key_payload *upayload; | |
77 | ||
78 | upayload = container_of(rcu, struct user_key_payload, rcu); | |
79 | ||
80 | kfree(upayload); | |
a8b17ed0 | 81 | } |
76d8aeab | 82 | |
1da177e4 LT |
83 | /* |
84 | * update a user defined key | |
76d8aeab | 85 | * - the key's semaphore is write-locked |
1da177e4 | 86 | */ |
2aa349f6 | 87 | int user_update(struct key *key, const void *data, size_t datalen) |
1da177e4 | 88 | { |
76d8aeab | 89 | struct user_key_payload *upayload, *zap; |
1da177e4 LT |
90 | int ret; |
91 | ||
92 | ret = -EINVAL; | |
93 | if (datalen <= 0 || datalen > 32767 || !data) | |
94 | goto error; | |
95 | ||
76d8aeab | 96 | /* construct a replacement payload */ |
1da177e4 | 97 | ret = -ENOMEM; |
76d8aeab DH |
98 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
99 | if (!upayload) | |
1da177e4 LT |
100 | goto error; |
101 | ||
76d8aeab DH |
102 | upayload->datalen = datalen; |
103 | memcpy(upayload->data, data, datalen); | |
1da177e4 LT |
104 | |
105 | /* check the quota and attach the new data */ | |
76d8aeab | 106 | zap = upayload; |
1da177e4 LT |
107 | |
108 | ret = key_payload_reserve(key, datalen); | |
109 | ||
110 | if (ret == 0) { | |
111 | /* attach the new data, displacing the old */ | |
112 | zap = key->payload.data; | |
76d8aeab | 113 | rcu_assign_pointer(key->payload.data, upayload); |
1da177e4 LT |
114 | key->expiry = 0; |
115 | } | |
116 | ||
76d8aeab | 117 | call_rcu(&zap->rcu, user_update_rcu_disposal); |
1da177e4 | 118 | |
2aa349f6 | 119 | error: |
1da177e4 | 120 | return ret; |
a8b17ed0 | 121 | } |
1da177e4 | 122 | |
2aa349f6 DH |
123 | EXPORT_SYMBOL_GPL(user_update); |
124 | ||
1da177e4 LT |
125 | /* |
126 | * match users on their name | |
127 | */ | |
2aa349f6 | 128 | int user_match(const struct key *key, const void *description) |
1da177e4 LT |
129 | { |
130 | return strcmp(key->description, description) == 0; | |
a8b17ed0 | 131 | } |
1da177e4 | 132 | |
2aa349f6 DH |
133 | EXPORT_SYMBOL_GPL(user_match); |
134 | ||
1da177e4 | 135 | /* |
31204ed9 DH |
136 | * dispose of the links from a revoked keyring |
137 | * - called with the key sem write-locked | |
138 | */ | |
139 | void user_revoke(struct key *key) | |
140 | { | |
141 | struct user_key_payload *upayload = key->payload.data; | |
142 | ||
143 | /* clear the quota */ | |
144 | key_payload_reserve(key, 0); | |
145 | ||
146 | if (upayload) { | |
147 | rcu_assign_pointer(key->payload.data, NULL); | |
148 | call_rcu(&upayload->rcu, user_update_rcu_disposal); | |
149 | } | |
a8b17ed0 | 150 | } |
31204ed9 DH |
151 | |
152 | EXPORT_SYMBOL(user_revoke); | |
153 | ||
31204ed9 DH |
154 | /* |
155 | * dispose of the data dangling from the corpse of a user key | |
1da177e4 | 156 | */ |
2aa349f6 | 157 | void user_destroy(struct key *key) |
1da177e4 | 158 | { |
76d8aeab DH |
159 | struct user_key_payload *upayload = key->payload.data; |
160 | ||
161 | kfree(upayload); | |
a8b17ed0 | 162 | } |
1da177e4 | 163 | |
2aa349f6 DH |
164 | EXPORT_SYMBOL_GPL(user_destroy); |
165 | ||
1da177e4 | 166 | /* |
76d8aeab | 167 | * describe the user key |
1da177e4 | 168 | */ |
2aa349f6 | 169 | void user_describe(const struct key *key, struct seq_file *m) |
1da177e4 LT |
170 | { |
171 | seq_puts(m, key->description); | |
172 | ||
173 | seq_printf(m, ": %u", key->datalen); | |
a8b17ed0 | 174 | } |
1da177e4 | 175 | |
2aa349f6 DH |
176 | EXPORT_SYMBOL_GPL(user_describe); |
177 | ||
1da177e4 LT |
178 | /* |
179 | * read the key data | |
76d8aeab | 180 | * - the key's semaphore is read-locked |
1da177e4 | 181 | */ |
2aa349f6 | 182 | long user_read(const struct key *key, char __user *buffer, size_t buflen) |
1da177e4 | 183 | { |
76d8aeab DH |
184 | struct user_key_payload *upayload; |
185 | long ret; | |
186 | ||
633e804e | 187 | upayload = rcu_dereference_key(key); |
76d8aeab | 188 | ret = upayload->datalen; |
1da177e4 LT |
189 | |
190 | /* we can return the data as is */ | |
191 | if (buffer && buflen > 0) { | |
76d8aeab DH |
192 | if (buflen > upayload->datalen) |
193 | buflen = upayload->datalen; | |
1da177e4 | 194 | |
76d8aeab | 195 | if (copy_to_user(buffer, upayload->data, buflen) != 0) |
1da177e4 LT |
196 | ret = -EFAULT; |
197 | } | |
198 | ||
199 | return ret; | |
a8b17ed0 | 200 | } |
2aa349f6 DH |
201 | |
202 | EXPORT_SYMBOL_GPL(user_read); |