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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> |
7c0f6ba6 | 18 | #include <linux/uaccess.h> |
1da177e4 LT |
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 | 28 | .name = "user", |
f9167789 DH |
29 | .preparse = user_preparse, |
30 | .free_preparse = user_free_preparse, | |
31 | .instantiate = generic_key_instantiate, | |
4bdf0bc3 | 32 | .update = user_update, |
4bdf0bc3 DH |
33 | .revoke = user_revoke, |
34 | .destroy = user_destroy, | |
35 | .describe = user_describe, | |
36 | .read = user_read, | |
1da177e4 LT |
37 | }; |
38 | ||
16c29b67 MH |
39 | EXPORT_SYMBOL_GPL(key_type_user); |
40 | ||
9f6ed2ca JL |
41 | /* |
42 | * This key type is essentially the same as key_type_user, but it does | |
43 | * not define a .read op. This is suitable for storing username and | |
44 | * password pairs in the keyring that you do not want to be readable | |
45 | * from userspace. | |
46 | */ | |
47 | struct key_type key_type_logon = { | |
48 | .name = "logon", | |
f9167789 DH |
49 | .preparse = user_preparse, |
50 | .free_preparse = user_free_preparse, | |
51 | .instantiate = generic_key_instantiate, | |
9f6ed2ca | 52 | .update = user_update, |
9f6ed2ca JL |
53 | .revoke = user_revoke, |
54 | .destroy = user_destroy, | |
55 | .describe = user_describe, | |
56 | .vet_description = logon_vet_description, | |
57 | }; | |
58 | EXPORT_SYMBOL_GPL(key_type_logon); | |
59 | ||
1da177e4 | 60 | /* |
f9167789 | 61 | * Preparse a user defined key payload |
1da177e4 | 62 | */ |
f9167789 | 63 | int user_preparse(struct key_preparsed_payload *prep) |
1da177e4 | 64 | { |
76d8aeab | 65 | struct user_key_payload *upayload; |
cf7f601c | 66 | size_t datalen = prep->datalen; |
1da177e4 | 67 | |
cf7f601c | 68 | if (datalen <= 0 || datalen > 32767 || !prep->data) |
f9167789 | 69 | return -EINVAL; |
1da177e4 | 70 | |
76d8aeab DH |
71 | upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL); |
72 | if (!upayload) | |
f9167789 | 73 | return -ENOMEM; |
1da177e4 | 74 | |
76d8aeab | 75 | /* attach the data */ |
f9167789 | 76 | prep->quotalen = datalen; |
146aa8b1 | 77 | prep->payload.data[0] = upayload; |
76d8aeab | 78 | upayload->datalen = datalen; |
cf7f601c | 79 | memcpy(upayload->data, prep->data, datalen); |
f9167789 | 80 | return 0; |
a8b17ed0 | 81 | } |
f9167789 | 82 | EXPORT_SYMBOL_GPL(user_preparse); |
31204ed9 | 83 | |
f9167789 DH |
84 | /* |
85 | * Free a preparse of a user defined key payload | |
86 | */ | |
87 | void user_free_preparse(struct key_preparsed_payload *prep) | |
88 | { | |
6966c749 | 89 | kzfree(prep->payload.data[0]); |
f9167789 DH |
90 | } |
91 | EXPORT_SYMBOL_GPL(user_free_preparse); | |
2aa349f6 | 92 | |
6966c749 EB |
93 | static void user_free_payload_rcu(struct rcu_head *head) |
94 | { | |
95 | struct user_key_payload *payload; | |
96 | ||
97 | payload = container_of(head, struct user_key_payload, rcu); | |
98 | kzfree(payload); | |
99 | } | |
100 | ||
1da177e4 LT |
101 | /* |
102 | * update a user defined key | |
76d8aeab | 103 | * - the key's semaphore is write-locked |
1da177e4 | 104 | */ |
cf7f601c | 105 | int user_update(struct key *key, struct key_preparsed_payload *prep) |
1da177e4 | 106 | { |
898de7d0 | 107 | struct user_key_payload *zap = NULL; |
1da177e4 LT |
108 | int ret; |
109 | ||
1da177e4 | 110 | /* check the quota and attach the new data */ |
898de7d0 DH |
111 | ret = key_payload_reserve(key, prep->datalen); |
112 | if (ret < 0) | |
113 | return ret; | |
114 | ||
115 | /* attach the new data, displacing the old */ | |
116 | key->expiry = prep->expiry; | |
fb6c49cf | 117 | if (key_is_positive(key)) |
0837e49a | 118 | zap = dereference_key_locked(key); |
898de7d0 DH |
119 | rcu_assign_keypointer(key, prep->payload.data[0]); |
120 | prep->payload.data[0] = NULL; | |
1da177e4 | 121 | |
9f35a33b | 122 | if (zap) |
6966c749 | 123 | call_rcu(&zap->rcu, user_free_payload_rcu); |
1da177e4 | 124 | return ret; |
a8b17ed0 | 125 | } |
2aa349f6 DH |
126 | EXPORT_SYMBOL_GPL(user_update); |
127 | ||
1da177e4 | 128 | /* |
31204ed9 DH |
129 | * dispose of the links from a revoked keyring |
130 | * - called with the key sem write-locked | |
131 | */ | |
132 | void user_revoke(struct key *key) | |
133 | { | |
0837e49a | 134 | struct user_key_payload *upayload = user_key_payload_locked(key); |
31204ed9 DH |
135 | |
136 | /* clear the quota */ | |
137 | key_payload_reserve(key, 0); | |
138 | ||
139 | if (upayload) { | |
f6b24579 | 140 | rcu_assign_keypointer(key, NULL); |
6966c749 | 141 | call_rcu(&upayload->rcu, user_free_payload_rcu); |
31204ed9 | 142 | } |
a8b17ed0 | 143 | } |
31204ed9 DH |
144 | |
145 | EXPORT_SYMBOL(user_revoke); | |
146 | ||
31204ed9 DH |
147 | /* |
148 | * dispose of the data dangling from the corpse of a user key | |
1da177e4 | 149 | */ |
2aa349f6 | 150 | void user_destroy(struct key *key) |
1da177e4 | 151 | { |
146aa8b1 | 152 | struct user_key_payload *upayload = key->payload.data[0]; |
76d8aeab | 153 | |
6966c749 | 154 | kzfree(upayload); |
a8b17ed0 | 155 | } |
1da177e4 | 156 | |
2aa349f6 DH |
157 | EXPORT_SYMBOL_GPL(user_destroy); |
158 | ||
1da177e4 | 159 | /* |
76d8aeab | 160 | * describe the user key |
1da177e4 | 161 | */ |
2aa349f6 | 162 | void user_describe(const struct key *key, struct seq_file *m) |
1da177e4 LT |
163 | { |
164 | seq_puts(m, key->description); | |
fb6c49cf | 165 | if (key_is_positive(key)) |
78b7280c | 166 | seq_printf(m, ": %u", key->datalen); |
a8b17ed0 | 167 | } |
1da177e4 | 168 | |
2aa349f6 DH |
169 | EXPORT_SYMBOL_GPL(user_describe); |
170 | ||
1da177e4 LT |
171 | /* |
172 | * read the key data | |
76d8aeab | 173 | * - the key's semaphore is read-locked |
1da177e4 | 174 | */ |
2aa349f6 | 175 | long user_read(const struct key *key, char __user *buffer, size_t buflen) |
1da177e4 | 176 | { |
146aa8b1 | 177 | const struct user_key_payload *upayload; |
76d8aeab DH |
178 | long ret; |
179 | ||
0837e49a | 180 | upayload = user_key_payload_locked(key); |
76d8aeab | 181 | ret = upayload->datalen; |
1da177e4 LT |
182 | |
183 | /* we can return the data as is */ | |
184 | if (buffer && buflen > 0) { | |
76d8aeab DH |
185 | if (buflen > upayload->datalen) |
186 | buflen = upayload->datalen; | |
1da177e4 | 187 | |
76d8aeab | 188 | if (copy_to_user(buffer, upayload->data, buflen) != 0) |
1da177e4 LT |
189 | ret = -EFAULT; |
190 | } | |
191 | ||
192 | return ret; | |
a8b17ed0 | 193 | } |
2aa349f6 DH |
194 | |
195 | EXPORT_SYMBOL_GPL(user_read); | |
9f6ed2ca JL |
196 | |
197 | /* Vet the description for a "logon" key */ | |
198 | static int logon_vet_description(const char *desc) | |
199 | { | |
200 | char *p; | |
201 | ||
202 | /* require a "qualified" description string */ | |
203 | p = strchr(desc, ':'); | |
204 | if (!p) | |
205 | return -EINVAL; | |
206 | ||
207 | /* also reject description with ':' as first char */ | |
208 | if (p == desc) | |
209 | return -EINVAL; | |
210 | ||
211 | return 0; | |
212 | } |