Commit | Line | Data |
---|---|---|
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> | |
14 | #include <linux/sched.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/seq_file.h> | |
17 | #include <linux/err.h> | |
2aa349f6 | 18 | #include <keys/user-type.h> |
1da177e4 LT |
19 | #include <asm/uaccess.h> |
20 | #include "internal.h" | |
21 | ||
1da177e4 LT |
22 | /* |
23 | * user defined keys take an arbitrary string as the description and an | |
24 | * arbitrary blob of data as the payload | |
25 | */ | |
26 | struct key_type key_type_user = { | |
27 | .name = "user", | |
28 | .instantiate = user_instantiate, | |
1da177e4 LT |
29 | .update = user_update, |
30 | .match = user_match, | |
31204ed9 | 31 | .revoke = user_revoke, |
1da177e4 LT |
32 | .destroy = user_destroy, |
33 | .describe = user_describe, | |
34 | .read = user_read, | |
35 | }; | |
36 | ||
16c29b67 MH |
37 | EXPORT_SYMBOL_GPL(key_type_user); |
38 | ||
1da177e4 LT |
39 | /*****************************************************************************/ |
40 | /* | |
41 | * instantiate a user defined key | |
42 | */ | |
2aa349f6 | 43 | int user_instantiate(struct key *key, const void *data, size_t datalen) |
1da177e4 | 44 | { |
76d8aeab | 45 | struct user_key_payload *upayload; |
1da177e4 LT |
46 | int ret; |
47 | ||
48 | ret = -EINVAL; | |
49 | if (datalen <= 0 || datalen > 32767 || !data) | |
50 | goto error; | |
51 | ||
52 | ret = key_payload_reserve(key, datalen); | |
53 | if (ret < 0) | |
54 | goto error; | |
55 | ||
1da177e4 | 56 | ret = -ENOMEM; |
76d8aeab DH |
57 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
58 | if (!upayload) | |
1da177e4 LT |
59 | goto error; |
60 | ||
76d8aeab DH |
61 | /* attach the data */ |
62 | upayload->datalen = datalen; | |
63 | memcpy(upayload->data, data, datalen); | |
64 | rcu_assign_pointer(key->payload.data, upayload); | |
1da177e4 LT |
65 | ret = 0; |
66 | ||
2aa349f6 | 67 | error: |
1da177e4 LT |
68 | return ret; |
69 | ||
70 | } /* end user_instantiate() */ | |
31204ed9 | 71 | |
2aa349f6 DH |
72 | EXPORT_SYMBOL_GPL(user_instantiate); |
73 | ||
76d8aeab DH |
74 | /*****************************************************************************/ |
75 | /* | |
76 | * dispose of the old data from an updated user defined key | |
77 | */ | |
78 | static void user_update_rcu_disposal(struct rcu_head *rcu) | |
79 | { | |
80 | struct user_key_payload *upayload; | |
81 | ||
82 | upayload = container_of(rcu, struct user_key_payload, rcu); | |
83 | ||
84 | kfree(upayload); | |
85 | ||
86 | } /* end user_update_rcu_disposal() */ | |
87 | ||
1da177e4 LT |
88 | /*****************************************************************************/ |
89 | /* | |
90 | * update a user defined key | |
76d8aeab | 91 | * - the key's semaphore is write-locked |
1da177e4 | 92 | */ |
2aa349f6 | 93 | int user_update(struct key *key, const void *data, size_t datalen) |
1da177e4 | 94 | { |
76d8aeab | 95 | struct user_key_payload *upayload, *zap; |
1da177e4 LT |
96 | int ret; |
97 | ||
98 | ret = -EINVAL; | |
99 | if (datalen <= 0 || datalen > 32767 || !data) | |
100 | goto error; | |
101 | ||
76d8aeab | 102 | /* construct a replacement payload */ |
1da177e4 | 103 | ret = -ENOMEM; |
76d8aeab DH |
104 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
105 | if (!upayload) | |
1da177e4 LT |
106 | goto error; |
107 | ||
76d8aeab DH |
108 | upayload->datalen = datalen; |
109 | memcpy(upayload->data, data, datalen); | |
1da177e4 LT |
110 | |
111 | /* check the quota and attach the new data */ | |
76d8aeab | 112 | zap = upayload; |
1da177e4 LT |
113 | |
114 | ret = key_payload_reserve(key, datalen); | |
115 | ||
116 | if (ret == 0) { | |
117 | /* attach the new data, displacing the old */ | |
118 | zap = key->payload.data; | |
76d8aeab | 119 | rcu_assign_pointer(key->payload.data, upayload); |
1da177e4 LT |
120 | key->expiry = 0; |
121 | } | |
122 | ||
76d8aeab | 123 | call_rcu(&zap->rcu, user_update_rcu_disposal); |
1da177e4 | 124 | |
2aa349f6 | 125 | error: |
1da177e4 LT |
126 | return ret; |
127 | ||
128 | } /* end user_update() */ | |
129 | ||
2aa349f6 DH |
130 | EXPORT_SYMBOL_GPL(user_update); |
131 | ||
1da177e4 LT |
132 | /*****************************************************************************/ |
133 | /* | |
134 | * match users on their name | |
135 | */ | |
2aa349f6 | 136 | int user_match(const struct key *key, const void *description) |
1da177e4 LT |
137 | { |
138 | return strcmp(key->description, description) == 0; | |
139 | ||
140 | } /* end user_match() */ | |
141 | ||
2aa349f6 DH |
142 | EXPORT_SYMBOL_GPL(user_match); |
143 | ||
1da177e4 LT |
144 | /*****************************************************************************/ |
145 | /* | |
31204ed9 DH |
146 | * dispose of the links from a revoked keyring |
147 | * - called with the key sem write-locked | |
148 | */ | |
149 | void user_revoke(struct key *key) | |
150 | { | |
151 | struct user_key_payload *upayload = key->payload.data; | |
152 | ||
153 | /* clear the quota */ | |
154 | key_payload_reserve(key, 0); | |
155 | ||
156 | if (upayload) { | |
157 | rcu_assign_pointer(key->payload.data, NULL); | |
158 | call_rcu(&upayload->rcu, user_update_rcu_disposal); | |
159 | } | |
160 | ||
161 | } /* end user_revoke() */ | |
162 | ||
163 | EXPORT_SYMBOL(user_revoke); | |
164 | ||
165 | /*****************************************************************************/ | |
166 | /* | |
167 | * dispose of the data dangling from the corpse of a user key | |
1da177e4 | 168 | */ |
2aa349f6 | 169 | void user_destroy(struct key *key) |
1da177e4 | 170 | { |
76d8aeab DH |
171 | struct user_key_payload *upayload = key->payload.data; |
172 | ||
173 | kfree(upayload); | |
1da177e4 LT |
174 | |
175 | } /* end user_destroy() */ | |
176 | ||
2aa349f6 DH |
177 | EXPORT_SYMBOL_GPL(user_destroy); |
178 | ||
1da177e4 LT |
179 | /*****************************************************************************/ |
180 | /* | |
76d8aeab | 181 | * describe the user key |
1da177e4 | 182 | */ |
2aa349f6 | 183 | void user_describe(const struct key *key, struct seq_file *m) |
1da177e4 LT |
184 | { |
185 | seq_puts(m, key->description); | |
186 | ||
187 | seq_printf(m, ": %u", key->datalen); | |
188 | ||
189 | } /* end user_describe() */ | |
190 | ||
2aa349f6 DH |
191 | EXPORT_SYMBOL_GPL(user_describe); |
192 | ||
1da177e4 LT |
193 | /*****************************************************************************/ |
194 | /* | |
195 | * read the key data | |
76d8aeab | 196 | * - the key's semaphore is read-locked |
1da177e4 | 197 | */ |
2aa349f6 | 198 | long user_read(const struct key *key, char __user *buffer, size_t buflen) |
1da177e4 | 199 | { |
76d8aeab DH |
200 | struct user_key_payload *upayload; |
201 | long ret; | |
202 | ||
203 | upayload = rcu_dereference(key->payload.data); | |
204 | ret = upayload->datalen; | |
1da177e4 LT |
205 | |
206 | /* we can return the data as is */ | |
207 | if (buffer && buflen > 0) { | |
76d8aeab DH |
208 | if (buflen > upayload->datalen) |
209 | buflen = upayload->datalen; | |
1da177e4 | 210 | |
76d8aeab | 211 | if (copy_to_user(buffer, upayload->data, buflen) != 0) |
1da177e4 LT |
212 | ret = -EFAULT; |
213 | } | |
214 | ||
215 | return ret; | |
216 | ||
217 | } /* end user_read() */ | |
2aa349f6 DH |
218 | |
219 | EXPORT_SYMBOL_GPL(user_read); |