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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 | ||
9f6ed2ca JL |
21 | static int logon_vet_description(const char *desc); |
22 | ||
1da177e4 LT |
23 | /* |
24 | * user defined keys take an arbitrary string as the description and an | |
25 | * arbitrary blob of data as the payload | |
26 | */ | |
27 | struct key_type key_type_user = { | |
4bdf0bc3 DH |
28 | .name = "user", |
29 | .def_lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, | |
f9167789 DH |
30 | .preparse = user_preparse, |
31 | .free_preparse = user_free_preparse, | |
32 | .instantiate = generic_key_instantiate, | |
4bdf0bc3 DH |
33 | .update = user_update, |
34 | .match = user_match, | |
35 | .revoke = user_revoke, | |
36 | .destroy = user_destroy, | |
37 | .describe = user_describe, | |
38 | .read = user_read, | |
1da177e4 LT |
39 | }; |
40 | ||
16c29b67 MH |
41 | EXPORT_SYMBOL_GPL(key_type_user); |
42 | ||
9f6ed2ca JL |
43 | /* |
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 | |
47 | * from userspace. | |
48 | */ | |
49 | struct key_type key_type_logon = { | |
50 | .name = "logon", | |
4bdf0bc3 | 51 | .def_lookup_type = KEYRING_SEARCH_LOOKUP_DIRECT, |
f9167789 DH |
52 | .preparse = user_preparse, |
53 | .free_preparse = user_free_preparse, | |
54 | .instantiate = generic_key_instantiate, | |
9f6ed2ca JL |
55 | .update = user_update, |
56 | .match = user_match, | |
57 | .revoke = user_revoke, | |
58 | .destroy = user_destroy, | |
59 | .describe = user_describe, | |
60 | .vet_description = logon_vet_description, | |
61 | }; | |
62 | EXPORT_SYMBOL_GPL(key_type_logon); | |
63 | ||
1da177e4 | 64 | /* |
f9167789 | 65 | * Preparse a user defined key payload |
1da177e4 | 66 | */ |
f9167789 | 67 | int user_preparse(struct key_preparsed_payload *prep) |
1da177e4 | 68 | { |
76d8aeab | 69 | struct user_key_payload *upayload; |
cf7f601c | 70 | size_t datalen = prep->datalen; |
1da177e4 | 71 | |
cf7f601c | 72 | if (datalen <= 0 || datalen > 32767 || !prep->data) |
f9167789 | 73 | return -EINVAL; |
1da177e4 | 74 | |
76d8aeab DH |
75 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
76 | if (!upayload) | |
f9167789 | 77 | return -ENOMEM; |
1da177e4 | 78 | |
76d8aeab | 79 | /* attach the data */ |
f9167789 DH |
80 | prep->quotalen = datalen; |
81 | prep->payload[0] = upayload; | |
76d8aeab | 82 | upayload->datalen = datalen; |
cf7f601c | 83 | memcpy(upayload->data, prep->data, datalen); |
f9167789 | 84 | return 0; |
a8b17ed0 | 85 | } |
f9167789 | 86 | EXPORT_SYMBOL_GPL(user_preparse); |
31204ed9 | 87 | |
f9167789 DH |
88 | /* |
89 | * Free a preparse of a user defined key payload | |
90 | */ | |
91 | void user_free_preparse(struct key_preparsed_payload *prep) | |
92 | { | |
93 | kfree(prep->payload[0]); | |
94 | } | |
95 | EXPORT_SYMBOL_GPL(user_free_preparse); | |
2aa349f6 | 96 | |
1da177e4 LT |
97 | /* |
98 | * update a user defined key | |
76d8aeab | 99 | * - the key's semaphore is write-locked |
1da177e4 | 100 | */ |
cf7f601c | 101 | int user_update(struct key *key, struct key_preparsed_payload *prep) |
1da177e4 | 102 | { |
76d8aeab | 103 | struct user_key_payload *upayload, *zap; |
cf7f601c | 104 | size_t datalen = prep->datalen; |
1da177e4 LT |
105 | int ret; |
106 | ||
107 | ret = -EINVAL; | |
cf7f601c | 108 | if (datalen <= 0 || datalen > 32767 || !prep->data) |
1da177e4 LT |
109 | goto error; |
110 | ||
76d8aeab | 111 | /* construct a replacement payload */ |
1da177e4 | 112 | ret = -ENOMEM; |
76d8aeab DH |
113 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
114 | if (!upayload) | |
1da177e4 LT |
115 | goto error; |
116 | ||
76d8aeab | 117 | upayload->datalen = datalen; |
cf7f601c | 118 | memcpy(upayload->data, prep->data, datalen); |
1da177e4 LT |
119 | |
120 | /* check the quota and attach the new data */ | |
76d8aeab | 121 | zap = upayload; |
1da177e4 LT |
122 | |
123 | ret = key_payload_reserve(key, datalen); | |
124 | ||
125 | if (ret == 0) { | |
126 | /* attach the new data, displacing the old */ | |
127 | zap = key->payload.data; | |
f6b24579 | 128 | rcu_assign_keypointer(key, upayload); |
1da177e4 LT |
129 | key->expiry = 0; |
130 | } | |
131 | ||
9f35a33b DH |
132 | if (zap) |
133 | kfree_rcu(zap, rcu); | |
1da177e4 | 134 | |
2aa349f6 | 135 | error: |
1da177e4 | 136 | return ret; |
a8b17ed0 | 137 | } |
1da177e4 | 138 | |
2aa349f6 DH |
139 | EXPORT_SYMBOL_GPL(user_update); |
140 | ||
1da177e4 LT |
141 | /* |
142 | * match users on their name | |
143 | */ | |
46291959 | 144 | int user_match(const struct key *key, const struct key_match_data *match_data) |
1da177e4 | 145 | { |
46291959 | 146 | return strcmp(key->description, match_data->raw_data) == 0; |
a8b17ed0 | 147 | } |
1da177e4 | 148 | |
2aa349f6 DH |
149 | EXPORT_SYMBOL_GPL(user_match); |
150 | ||
1da177e4 | 151 | /* |
31204ed9 DH |
152 | * dispose of the links from a revoked keyring |
153 | * - called with the key sem write-locked | |
154 | */ | |
155 | void user_revoke(struct key *key) | |
156 | { | |
157 | struct user_key_payload *upayload = key->payload.data; | |
158 | ||
159 | /* clear the quota */ | |
160 | key_payload_reserve(key, 0); | |
161 | ||
162 | if (upayload) { | |
f6b24579 | 163 | rcu_assign_keypointer(key, NULL); |
3acb458c | 164 | kfree_rcu(upayload, rcu); |
31204ed9 | 165 | } |
a8b17ed0 | 166 | } |
31204ed9 DH |
167 | |
168 | EXPORT_SYMBOL(user_revoke); | |
169 | ||
31204ed9 DH |
170 | /* |
171 | * dispose of the data dangling from the corpse of a user key | |
1da177e4 | 172 | */ |
2aa349f6 | 173 | void user_destroy(struct key *key) |
1da177e4 | 174 | { |
76d8aeab DH |
175 | struct user_key_payload *upayload = key->payload.data; |
176 | ||
177 | kfree(upayload); | |
a8b17ed0 | 178 | } |
1da177e4 | 179 | |
2aa349f6 DH |
180 | EXPORT_SYMBOL_GPL(user_destroy); |
181 | ||
1da177e4 | 182 | /* |
76d8aeab | 183 | * describe the user key |
1da177e4 | 184 | */ |
2aa349f6 | 185 | void user_describe(const struct key *key, struct seq_file *m) |
1da177e4 LT |
186 | { |
187 | seq_puts(m, key->description); | |
78b7280c DH |
188 | if (key_is_instantiated(key)) |
189 | seq_printf(m, ": %u", key->datalen); | |
a8b17ed0 | 190 | } |
1da177e4 | 191 | |
2aa349f6 DH |
192 | EXPORT_SYMBOL_GPL(user_describe); |
193 | ||
1da177e4 LT |
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 | ||
633e804e | 203 | upayload = rcu_dereference_key(key); |
76d8aeab | 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; | |
a8b17ed0 | 216 | } |
2aa349f6 DH |
217 | |
218 | EXPORT_SYMBOL_GPL(user_read); | |
9f6ed2ca JL |
219 | |
220 | /* Vet the description for a "logon" key */ | |
221 | static int logon_vet_description(const char *desc) | |
222 | { | |
223 | char *p; | |
224 | ||
225 | /* require a "qualified" description string */ | |
226 | p = strchr(desc, ':'); | |
227 | if (!p) | |
228 | return -EINVAL; | |
229 | ||
230 | /* also reject description with ':' as first char */ | |
231 | if (p == desc) | |
232 | return -EINVAL; | |
233 | ||
234 | return 0; | |
235 | } |