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 | ||
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 | */ | |
cf7f601c | 61 | int user_instantiate(struct key *key, struct key_preparsed_payload *prep) |
1da177e4 | 62 | { |
76d8aeab | 63 | struct user_key_payload *upayload; |
cf7f601c | 64 | size_t datalen = prep->datalen; |
1da177e4 LT |
65 | int ret; |
66 | ||
67 | ret = -EINVAL; | |
cf7f601c | 68 | if (datalen <= 0 || datalen > 32767 || !prep->data) |
1da177e4 LT |
69 | goto error; |
70 | ||
71 | ret = key_payload_reserve(key, datalen); | |
72 | if (ret < 0) | |
73 | goto error; | |
74 | ||
1da177e4 | 75 | ret = -ENOMEM; |
76d8aeab DH |
76 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
77 | if (!upayload) | |
1da177e4 LT |
78 | goto error; |
79 | ||
76d8aeab DH |
80 | /* attach the data */ |
81 | upayload->datalen = datalen; | |
cf7f601c | 82 | memcpy(upayload->data, prep->data, datalen); |
f6b24579 | 83 | rcu_assign_keypointer(key, upayload); |
1da177e4 LT |
84 | ret = 0; |
85 | ||
2aa349f6 | 86 | error: |
1da177e4 | 87 | return ret; |
a8b17ed0 | 88 | } |
31204ed9 | 89 | |
2aa349f6 DH |
90 | EXPORT_SYMBOL_GPL(user_instantiate); |
91 | ||
1da177e4 LT |
92 | /* |
93 | * update a user defined key | |
76d8aeab | 94 | * - the key's semaphore is write-locked |
1da177e4 | 95 | */ |
cf7f601c | 96 | int user_update(struct key *key, struct key_preparsed_payload *prep) |
1da177e4 | 97 | { |
76d8aeab | 98 | struct user_key_payload *upayload, *zap; |
cf7f601c | 99 | size_t datalen = prep->datalen; |
1da177e4 LT |
100 | int ret; |
101 | ||
102 | ret = -EINVAL; | |
cf7f601c | 103 | if (datalen <= 0 || datalen > 32767 || !prep->data) |
1da177e4 LT |
104 | goto error; |
105 | ||
76d8aeab | 106 | /* construct a replacement payload */ |
1da177e4 | 107 | ret = -ENOMEM; |
76d8aeab DH |
108 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
109 | if (!upayload) | |
1da177e4 LT |
110 | goto error; |
111 | ||
76d8aeab | 112 | upayload->datalen = datalen; |
cf7f601c | 113 | memcpy(upayload->data, prep->data, datalen); |
1da177e4 LT |
114 | |
115 | /* check the quota and attach the new data */ | |
76d8aeab | 116 | zap = upayload; |
1da177e4 LT |
117 | |
118 | ret = key_payload_reserve(key, datalen); | |
119 | ||
120 | if (ret == 0) { | |
121 | /* attach the new data, displacing the old */ | |
122 | zap = key->payload.data; | |
f6b24579 | 123 | rcu_assign_keypointer(key, upayload); |
1da177e4 LT |
124 | key->expiry = 0; |
125 | } | |
126 | ||
9f35a33b DH |
127 | if (zap) |
128 | kfree_rcu(zap, rcu); | |
1da177e4 | 129 | |
2aa349f6 | 130 | error: |
1da177e4 | 131 | return ret; |
a8b17ed0 | 132 | } |
1da177e4 | 133 | |
2aa349f6 DH |
134 | EXPORT_SYMBOL_GPL(user_update); |
135 | ||
1da177e4 LT |
136 | /* |
137 | * match users on their name | |
138 | */ | |
2aa349f6 | 139 | int user_match(const struct key *key, const void *description) |
1da177e4 LT |
140 | { |
141 | return strcmp(key->description, description) == 0; | |
a8b17ed0 | 142 | } |
1da177e4 | 143 | |
2aa349f6 DH |
144 | EXPORT_SYMBOL_GPL(user_match); |
145 | ||
1da177e4 | 146 | /* |
31204ed9 DH |
147 | * dispose of the links from a revoked keyring |
148 | * - called with the key sem write-locked | |
149 | */ | |
150 | void user_revoke(struct key *key) | |
151 | { | |
152 | struct user_key_payload *upayload = key->payload.data; | |
153 | ||
154 | /* clear the quota */ | |
155 | key_payload_reserve(key, 0); | |
156 | ||
157 | if (upayload) { | |
f6b24579 | 158 | rcu_assign_keypointer(key, NULL); |
3acb458c | 159 | kfree_rcu(upayload, rcu); |
31204ed9 | 160 | } |
a8b17ed0 | 161 | } |
31204ed9 DH |
162 | |
163 | EXPORT_SYMBOL(user_revoke); | |
164 | ||
31204ed9 DH |
165 | /* |
166 | * dispose of the data dangling from the corpse of a user key | |
1da177e4 | 167 | */ |
2aa349f6 | 168 | void user_destroy(struct key *key) |
1da177e4 | 169 | { |
76d8aeab DH |
170 | struct user_key_payload *upayload = key->payload.data; |
171 | ||
172 | kfree(upayload); | |
a8b17ed0 | 173 | } |
1da177e4 | 174 | |
2aa349f6 DH |
175 | EXPORT_SYMBOL_GPL(user_destroy); |
176 | ||
1da177e4 | 177 | /* |
76d8aeab | 178 | * describe the user key |
1da177e4 | 179 | */ |
2aa349f6 | 180 | void user_describe(const struct key *key, struct seq_file *m) |
1da177e4 LT |
181 | { |
182 | seq_puts(m, key->description); | |
78b7280c DH |
183 | if (key_is_instantiated(key)) |
184 | seq_printf(m, ": %u", key->datalen); | |
a8b17ed0 | 185 | } |
1da177e4 | 186 | |
2aa349f6 DH |
187 | EXPORT_SYMBOL_GPL(user_describe); |
188 | ||
1da177e4 LT |
189 | /* |
190 | * read the key data | |
76d8aeab | 191 | * - the key's semaphore is read-locked |
1da177e4 | 192 | */ |
2aa349f6 | 193 | long user_read(const struct key *key, char __user *buffer, size_t buflen) |
1da177e4 | 194 | { |
76d8aeab DH |
195 | struct user_key_payload *upayload; |
196 | long ret; | |
197 | ||
633e804e | 198 | upayload = rcu_dereference_key(key); |
76d8aeab | 199 | ret = upayload->datalen; |
1da177e4 LT |
200 | |
201 | /* we can return the data as is */ | |
202 | if (buffer && buflen > 0) { | |
76d8aeab DH |
203 | if (buflen > upayload->datalen) |
204 | buflen = upayload->datalen; | |
1da177e4 | 205 | |
76d8aeab | 206 | if (copy_to_user(buffer, upayload->data, buflen) != 0) |
1da177e4 LT |
207 | ret = -EFAULT; |
208 | } | |
209 | ||
210 | return ret; | |
a8b17ed0 | 211 | } |
2aa349f6 DH |
212 | |
213 | EXPORT_SYMBOL_GPL(user_read); | |
9f6ed2ca JL |
214 | |
215 | /* Vet the description for a "logon" key */ | |
216 | static int logon_vet_description(const char *desc) | |
217 | { | |
218 | char *p; | |
219 | ||
220 | /* require a "qualified" description string */ | |
221 | p = strchr(desc, ':'); | |
222 | if (!p) | |
223 | return -EINVAL; | |
224 | ||
225 | /* also reject description with ':' as first char */ | |
226 | if (p == desc) | |
227 | return -EINVAL; | |
228 | ||
229 | return 0; | |
230 | } |