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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/slab.h>
15#include <linux/seq_file.h>
16#include <linux/err.h>
17#include <keys/user-type.h>
18#include <asm/uaccess.h>
19#include "internal.h"
20
21static int logon_vet_description(const char *desc);
22
23/*
24 * user defined keys take an arbitrary string as the description and an
25 * arbitrary blob of data as the payload
26 */
27struct key_type key_type_user = {
28 .name = "user",
29 .preparse = user_preparse,
30 .free_preparse = user_free_preparse,
31 .instantiate = generic_key_instantiate,
32 .update = user_update,
33 .revoke = user_revoke,
34 .destroy = user_destroy,
35 .describe = user_describe,
36 .read = user_read,
37};
38
39EXPORT_SYMBOL_GPL(key_type_user);
40
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 */
47struct key_type key_type_logon = {
48 .name = "logon",
49 .preparse = user_preparse,
50 .free_preparse = user_free_preparse,
51 .instantiate = generic_key_instantiate,
52 .update = user_update,
53 .revoke = user_revoke,
54 .destroy = user_destroy,
55 .describe = user_describe,
56 .vet_description = logon_vet_description,
57};
58EXPORT_SYMBOL_GPL(key_type_logon);
59
60/*
61 * Preparse a user defined key payload
62 */
63int user_preparse(struct key_preparsed_payload *prep)
64{
65 struct user_key_payload *upayload;
66 size_t datalen = prep->datalen;
67
68 if (datalen <= 0 || datalen > 32767 || !prep->data)
69 return -EINVAL;
70
71 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
72 if (!upayload)
73 return -ENOMEM;
74
75 /* attach the data */
76 prep->quotalen = datalen;
77 prep->payload.data[0] = upayload;
78 upayload->datalen = datalen;
79 memcpy(upayload->data, prep->data, datalen);
80 return 0;
81}
82EXPORT_SYMBOL_GPL(user_preparse);
83
84/*
85 * Free a preparse of a user defined key payload
86 */
87void user_free_preparse(struct key_preparsed_payload *prep)
88{
89 kfree(prep->payload.data[0]);
90}
91EXPORT_SYMBOL_GPL(user_free_preparse);
92
93/*
94 * update a user defined key
95 * - the key's semaphore is write-locked
96 */
97int user_update(struct key *key, struct key_preparsed_payload *prep)
98{
99 struct user_key_payload *upayload, *zap;
100 size_t datalen = prep->datalen;
101 int ret;
102
103 ret = -EINVAL;
104 if (datalen <= 0 || datalen > 32767 || !prep->data)
105 goto error;
106
107 /* construct a replacement payload */
108 ret = -ENOMEM;
109 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
110 if (!upayload)
111 goto error;
112
113 upayload->datalen = datalen;
114 memcpy(upayload->data, prep->data, datalen);
115
116 /* check the quota and attach the new data */
117 zap = upayload;
118
119 ret = key_payload_reserve(key, datalen);
120
121 if (ret == 0) {
122 /* attach the new data, displacing the old */
123 if (!test_bit(KEY_FLAG_NEGATIVE, &key->flags))
124 zap = key->payload.data[0];
125 else
126 zap = NULL;
127 rcu_assign_keypointer(key, upayload);
128 key->expiry = 0;
129 }
130
131 if (zap)
132 kfree_rcu(zap, rcu);
133
134error:
135 return ret;
136}
137
138EXPORT_SYMBOL_GPL(user_update);
139
140/*
141 * dispose of the links from a revoked keyring
142 * - called with the key sem write-locked
143 */
144void user_revoke(struct key *key)
145{
146 struct user_key_payload *upayload = key->payload.data[0];
147
148 /* clear the quota */
149 key_payload_reserve(key, 0);
150
151 if (upayload) {
152 rcu_assign_keypointer(key, NULL);
153 kfree_rcu(upayload, rcu);
154 }
155}
156
157EXPORT_SYMBOL(user_revoke);
158
159/*
160 * dispose of the data dangling from the corpse of a user key
161 */
162void user_destroy(struct key *key)
163{
164 struct user_key_payload *upayload = key->payload.data[0];
165
166 kfree(upayload);
167}
168
169EXPORT_SYMBOL_GPL(user_destroy);
170
171/*
172 * describe the user key
173 */
174void user_describe(const struct key *key, struct seq_file *m)
175{
176 seq_puts(m, key->description);
177 if (key_is_instantiated(key))
178 seq_printf(m, ": %u", key->datalen);
179}
180
181EXPORT_SYMBOL_GPL(user_describe);
182
183/*
184 * read the key data
185 * - the key's semaphore is read-locked
186 */
187long user_read(const struct key *key, char __user *buffer, size_t buflen)
188{
189 const struct user_key_payload *upayload;
190 long ret;
191
192 upayload = user_key_payload(key);
193 ret = upayload->datalen;
194
195 /* we can return the data as is */
196 if (buffer && buflen > 0) {
197 if (buflen > upayload->datalen)
198 buflen = upayload->datalen;
199
200 if (copy_to_user(buffer, upayload->data, buflen) != 0)
201 ret = -EFAULT;
202 }
203
204 return ret;
205}
206
207EXPORT_SYMBOL_GPL(user_read);
208
209/* Vet the description for a "logon" key */
210static int logon_vet_description(const char *desc)
211{
212 char *p;
213
214 /* require a "qualified" description string */
215 p = strchr(desc, ':');
216 if (!p)
217 return -EINVAL;
218
219 /* also reject description with ':' as first char */
220 if (p == desc)
221 return -EINVAL;
222
223 return 0;
224}
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/slab.h>
15#include <linux/seq_file.h>
16#include <linux/err.h>
17#include <keys/user-type.h>
18#include <asm/uaccess.h>
19#include "internal.h"
20
21static int logon_vet_description(const char *desc);
22
23/*
24 * user defined keys take an arbitrary string as the description and an
25 * arbitrary blob of data as the payload
26 */
27struct key_type key_type_user = {
28 .name = "user",
29 .instantiate = user_instantiate,
30 .update = user_update,
31 .match = user_match,
32 .revoke = user_revoke,
33 .destroy = user_destroy,
34 .describe = user_describe,
35 .read = user_read,
36};
37
38EXPORT_SYMBOL_GPL(key_type_user);
39
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 */
46struct 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};
56EXPORT_SYMBOL_GPL(key_type_logon);
57
58/*
59 * instantiate a user defined key
60 */
61int user_instantiate(struct key *key, const void *data, size_t datalen)
62{
63 struct user_key_payload *upayload;
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
74 ret = -ENOMEM;
75 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
76 if (!upayload)
77 goto error;
78
79 /* attach the data */
80 upayload->datalen = datalen;
81 memcpy(upayload->data, data, datalen);
82 rcu_assign_keypointer(key, upayload);
83 ret = 0;
84
85error:
86 return ret;
87}
88
89EXPORT_SYMBOL_GPL(user_instantiate);
90
91/*
92 * update a user defined key
93 * - the key's semaphore is write-locked
94 */
95int user_update(struct key *key, const void *data, size_t datalen)
96{
97 struct user_key_payload *upayload, *zap;
98 int ret;
99
100 ret = -EINVAL;
101 if (datalen <= 0 || datalen > 32767 || !data)
102 goto error;
103
104 /* construct a replacement payload */
105 ret = -ENOMEM;
106 upayload = kmalloc(sizeof(*upayload) + datalen, GFP_KERNEL);
107 if (!upayload)
108 goto error;
109
110 upayload->datalen = datalen;
111 memcpy(upayload->data, data, datalen);
112
113 /* check the quota and attach the new data */
114 zap = upayload;
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;
121 rcu_assign_keypointer(key, upayload);
122 key->expiry = 0;
123 }
124
125 if (zap)
126 kfree_rcu(zap, rcu);
127
128error:
129 return ret;
130}
131
132EXPORT_SYMBOL_GPL(user_update);
133
134/*
135 * match users on their name
136 */
137int user_match(const struct key *key, const void *description)
138{
139 return strcmp(key->description, description) == 0;
140}
141
142EXPORT_SYMBOL_GPL(user_match);
143
144/*
145 * dispose of the links from a revoked keyring
146 * - called with the key sem write-locked
147 */
148void 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) {
156 rcu_assign_keypointer(key, NULL);
157 kfree_rcu(upayload, rcu);
158 }
159}
160
161EXPORT_SYMBOL(user_revoke);
162
163/*
164 * dispose of the data dangling from the corpse of a user key
165 */
166void user_destroy(struct key *key)
167{
168 struct user_key_payload *upayload = key->payload.data;
169
170 kfree(upayload);
171}
172
173EXPORT_SYMBOL_GPL(user_destroy);
174
175/*
176 * describe the user key
177 */
178void user_describe(const struct key *key, struct seq_file *m)
179{
180 seq_puts(m, key->description);
181 if (key_is_instantiated(key))
182 seq_printf(m, ": %u", key->datalen);
183}
184
185EXPORT_SYMBOL_GPL(user_describe);
186
187/*
188 * read the key data
189 * - the key's semaphore is read-locked
190 */
191long user_read(const struct key *key, char __user *buffer, size_t buflen)
192{
193 struct user_key_payload *upayload;
194 long ret;
195
196 upayload = rcu_dereference_key(key);
197 ret = upayload->datalen;
198
199 /* we can return the data as is */
200 if (buffer && buflen > 0) {
201 if (buflen > upayload->datalen)
202 buflen = upayload->datalen;
203
204 if (copy_to_user(buffer, upayload->data, buflen) != 0)
205 ret = -EFAULT;
206 }
207
208 return ret;
209}
210
211EXPORT_SYMBOL_GPL(user_read);
212
213/* Vet the description for a "logon" key */
214static 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}