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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 = { | |
28 | .name = "user", | |
29 | .instantiate = user_instantiate, | |
1da177e4 LT |
30 | .update = user_update, |
31 | .match = user_match, | |
31204ed9 | 32 | .revoke = user_revoke, |
1da177e4 LT |
33 | .destroy = user_destroy, |
34 | .describe = user_describe, | |
35 | .read = user_read, | |
36 | }; | |
37 | ||
16c29b67 MH |
38 | EXPORT_SYMBOL_GPL(key_type_user); |
39 | ||
9f6ed2ca JL |
40 | /* |
41 | * This key type is essentially the same as key_type_user, but it does | |
42 | * not define a .read op. This is suitable for storing username and | |
43 | * password pairs in the keyring that you do not want to be readable | |
44 | * from userspace. | |
45 | */ | |
46 | struct key_type key_type_logon = { | |
47 | .name = "logon", | |
48 | .instantiate = user_instantiate, | |
49 | .update = user_update, | |
50 | .match = user_match, | |
51 | .revoke = user_revoke, | |
52 | .destroy = user_destroy, | |
53 | .describe = user_describe, | |
54 | .vet_description = logon_vet_description, | |
55 | }; | |
56 | EXPORT_SYMBOL_GPL(key_type_logon); | |
57 | ||
1da177e4 LT |
58 | /* |
59 | * instantiate a user defined key | |
60 | */ | |
2aa349f6 | 61 | int user_instantiate(struct key *key, const void *data, size_t datalen) |
1da177e4 | 62 | { |
76d8aeab | 63 | struct user_key_payload *upayload; |
1da177e4 LT |
64 | int ret; |
65 | ||
66 | ret = -EINVAL; | |
67 | if (datalen <= 0 || datalen > 32767 || !data) | |
68 | goto error; | |
69 | ||
70 | ret = key_payload_reserve(key, datalen); | |
71 | if (ret < 0) | |
72 | goto error; | |
73 | ||
1da177e4 | 74 | ret = -ENOMEM; |
76d8aeab DH |
75 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
76 | if (!upayload) | |
1da177e4 LT |
77 | goto error; |
78 | ||
76d8aeab DH |
79 | /* attach the data */ |
80 | upayload->datalen = datalen; | |
81 | memcpy(upayload->data, data, datalen); | |
f6b24579 | 82 | rcu_assign_keypointer(key, upayload); |
1da177e4 LT |
83 | ret = 0; |
84 | ||
2aa349f6 | 85 | error: |
1da177e4 | 86 | return ret; |
a8b17ed0 | 87 | } |
31204ed9 | 88 | |
2aa349f6 DH |
89 | EXPORT_SYMBOL_GPL(user_instantiate); |
90 | ||
1da177e4 LT |
91 | /* |
92 | * update a user defined key | |
76d8aeab | 93 | * - the key's semaphore is write-locked |
1da177e4 | 94 | */ |
2aa349f6 | 95 | int user_update(struct key *key, const void *data, size_t datalen) |
1da177e4 | 96 | { |
76d8aeab | 97 | struct user_key_payload *upayload, *zap; |
1da177e4 LT |
98 | int ret; |
99 | ||
100 | ret = -EINVAL; | |
101 | if (datalen <= 0 || datalen > 32767 || !data) | |
102 | goto error; | |
103 | ||
76d8aeab | 104 | /* construct a replacement payload */ |
1da177e4 | 105 | ret = -ENOMEM; |
76d8aeab DH |
106 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
107 | if (!upayload) | |
1da177e4 LT |
108 | goto error; |
109 | ||
76d8aeab DH |
110 | upayload->datalen = datalen; |
111 | memcpy(upayload->data, data, datalen); | |
1da177e4 LT |
112 | |
113 | /* check the quota and attach the new data */ | |
76d8aeab | 114 | zap = upayload; |
1da177e4 LT |
115 | |
116 | ret = key_payload_reserve(key, datalen); | |
117 | ||
118 | if (ret == 0) { | |
119 | /* attach the new data, displacing the old */ | |
120 | zap = key->payload.data; | |
f6b24579 | 121 | rcu_assign_keypointer(key, upayload); |
1da177e4 LT |
122 | key->expiry = 0; |
123 | } | |
124 | ||
9f35a33b DH |
125 | if (zap) |
126 | kfree_rcu(zap, rcu); | |
1da177e4 | 127 | |
2aa349f6 | 128 | error: |
1da177e4 | 129 | return ret; |
a8b17ed0 | 130 | } |
1da177e4 | 131 | |
2aa349f6 DH |
132 | EXPORT_SYMBOL_GPL(user_update); |
133 | ||
1da177e4 LT |
134 | /* |
135 | * match users on their name | |
136 | */ | |
2aa349f6 | 137 | int user_match(const struct key *key, const void *description) |
1da177e4 LT |
138 | { |
139 | return strcmp(key->description, description) == 0; | |
a8b17ed0 | 140 | } |
1da177e4 | 141 | |
2aa349f6 DH |
142 | EXPORT_SYMBOL_GPL(user_match); |
143 | ||
1da177e4 | 144 | /* |
31204ed9 DH |
145 | * dispose of the links from a revoked keyring |
146 | * - called with the key sem write-locked | |
147 | */ | |
148 | void user_revoke(struct key *key) | |
149 | { | |
150 | struct user_key_payload *upayload = key->payload.data; | |
151 | ||
152 | /* clear the quota */ | |
153 | key_payload_reserve(key, 0); | |
154 | ||
155 | if (upayload) { | |
f6b24579 | 156 | rcu_assign_keypointer(key, NULL); |
3acb458c | 157 | kfree_rcu(upayload, rcu); |
31204ed9 | 158 | } |
a8b17ed0 | 159 | } |
31204ed9 DH |
160 | |
161 | EXPORT_SYMBOL(user_revoke); | |
162 | ||
31204ed9 DH |
163 | /* |
164 | * dispose of the data dangling from the corpse of a user key | |
1da177e4 | 165 | */ |
2aa349f6 | 166 | void user_destroy(struct key *key) |
1da177e4 | 167 | { |
76d8aeab DH |
168 | struct user_key_payload *upayload = key->payload.data; |
169 | ||
170 | kfree(upayload); | |
a8b17ed0 | 171 | } |
1da177e4 | 172 | |
2aa349f6 DH |
173 | EXPORT_SYMBOL_GPL(user_destroy); |
174 | ||
1da177e4 | 175 | /* |
76d8aeab | 176 | * describe the user key |
1da177e4 | 177 | */ |
2aa349f6 | 178 | void user_describe(const struct key *key, struct seq_file *m) |
1da177e4 LT |
179 | { |
180 | seq_puts(m, key->description); | |
78b7280c DH |
181 | if (key_is_instantiated(key)) |
182 | seq_printf(m, ": %u", key->datalen); | |
a8b17ed0 | 183 | } |
1da177e4 | 184 | |
2aa349f6 DH |
185 | EXPORT_SYMBOL_GPL(user_describe); |
186 | ||
1da177e4 LT |
187 | /* |
188 | * read the key data | |
76d8aeab | 189 | * - the key's semaphore is read-locked |
1da177e4 | 190 | */ |
2aa349f6 | 191 | long user_read(const struct key *key, char __user *buffer, size_t buflen) |
1da177e4 | 192 | { |
76d8aeab DH |
193 | struct user_key_payload *upayload; |
194 | long ret; | |
195 | ||
633e804e | 196 | upayload = rcu_dereference_key(key); |
76d8aeab | 197 | ret = upayload->datalen; |
1da177e4 LT |
198 | |
199 | /* we can return the data as is */ | |
200 | if (buffer && buflen > 0) { | |
76d8aeab DH |
201 | if (buflen > upayload->datalen) |
202 | buflen = upayload->datalen; | |
1da177e4 | 203 | |
76d8aeab | 204 | if (copy_to_user(buffer, upayload->data, buflen) != 0) |
1da177e4 LT |
205 | ret = -EFAULT; |
206 | } | |
207 | ||
208 | return ret; | |
a8b17ed0 | 209 | } |
2aa349f6 DH |
210 | |
211 | EXPORT_SYMBOL_GPL(user_read); | |
9f6ed2ca JL |
212 | |
213 | /* Vet the description for a "logon" key */ | |
214 | static int logon_vet_description(const char *desc) | |
215 | { | |
216 | char *p; | |
217 | ||
218 | /* require a "qualified" description string */ | |
219 | p = strchr(desc, ':'); | |
220 | if (!p) | |
221 | return -EINVAL; | |
222 | ||
223 | /* also reject description with ':' as first char */ | |
224 | if (p == desc) | |
225 | return -EINVAL; | |
226 | ||
227 | return 0; | |
228 | } |