1 /* key.h: authentication token and access key management
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 * See Documentation/keys.txt for information on keys/keyrings.
13 */
14
15 #ifndef _LINUX_KEY_H
16 #define _LINUX_KEY_H
17
18 #include <linux/types.h>
19 #include <linux/list.h>
20 #include <linux/rbtree.h>
21 #include <linux/spinlock.h>
22 #include <asm/atomic.h>
23
24 #ifdef __KERNEL__
25
26 /* key handle serial number */
27 typedef int32_t key_serial_t;
28
29 /* key handle permissions mask */
30 typedef uint32_t key_perm_t;
31
32 struct key;
33
34 #ifdef CONFIG_KEYS
35
36 #undef KEY_DEBUGGING
37
38 #define KEY_USR_VIEW 0x00010000 /* user can view a key's attributes */
39 #define KEY_USR_READ 0x00020000 /* user can read key payload / view keyring */
40 #define KEY_USR_WRITE 0x00040000 /* user can update key payload / add link to keyring */
41 #define KEY_USR_SEARCH 0x00080000 /* user can find a key in search / search a keyring */
42 #define KEY_USR_LINK 0x00100000 /* user can create a link to a key/keyring */
43 #define KEY_USR_ALL 0x001f0000
44
45 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */
46 #define KEY_GRP_READ 0x00000200
47 #define KEY_GRP_WRITE 0x00000400
48 #define KEY_GRP_SEARCH 0x00000800
49 #define KEY_GRP_LINK 0x00001000
50 #define KEY_GRP_ALL 0x00001f00
51
52 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
53 #define KEY_OTH_READ 0x00000002
54 #define KEY_OTH_WRITE 0x00000004
55 #define KEY_OTH_SEARCH 0x00000008
56 #define KEY_OTH_LINK 0x00000010
57 #define KEY_OTH_ALL 0x0000001f
58
59 struct seq_file;
60 struct user_struct;
61
62 struct key_type;
63 struct key_owner;
64 struct keyring_list;
65 struct keyring_name;
66
67 /*****************************************************************************/
68 /*
69 * authentication token / access credential / keyring
70 * - types of key include:
71 * - keyrings
72 * - disk encryption IDs
73 * - Kerberos TGTs and tickets
74 */
75 struct key {
76 atomic_t usage; /* number of references */
77 key_serial_t serial; /* key serial number */
78 struct rb_node serial_node;
79 struct key_type *type; /* type of key */
80 rwlock_t lock; /* examination vs change lock */
81 struct rw_semaphore sem; /* change vs change sem */
82 struct key_user *user; /* owner of this key */
83 time_t expiry; /* time at which key expires (or 0) */
84 uid_t uid;
85 gid_t gid;
86 key_perm_t perm; /* access permissions */
87 unsigned short quotalen; /* length added to quota */
88 unsigned short datalen; /* payload data length */
89 unsigned short flags; /* status flags (change with lock writelocked) */
90 #define KEY_FLAG_INSTANTIATED 0x00000001 /* set if key has been instantiated */
91 #define KEY_FLAG_DEAD 0x00000002 /* set if key type has been deleted */
92 #define KEY_FLAG_REVOKED 0x00000004 /* set if key had been revoked */
93 #define KEY_FLAG_IN_QUOTA 0x00000008 /* set if key consumes quota */
94 #define KEY_FLAG_USER_CONSTRUCT 0x00000010 /* set if key is being constructed in userspace */
95 #define KEY_FLAG_NEGATIVE 0x00000020 /* set if key is negative */
96
97 #ifdef KEY_DEBUGGING
98 unsigned magic;
99 #define KEY_DEBUG_MAGIC 0x18273645u
100 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
101 #endif
102
103 /* the description string
104 * - this is used to match a key against search criteria
105 * - this should be a printable string
106 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
107 */
108 char *description;
109
110 /* type specific data
111 * - this is used by the keyring type to index the name
112 */
113 union {
114 struct list_head link;
115 } type_data;
116
117 /* key data
118 * - this is used to hold the data actually used in cryptography or
119 * whatever
120 */
121 union {
122 unsigned long value;
123 void *data;
124 struct keyring_list *subscriptions;
125 } payload;
126 };
127
128 /*****************************************************************************/
129 /*
130 * kernel managed key type definition
131 */
132 struct key_type {
133 /* name of the type */
134 const char *name;
135
136 /* default payload length for quota precalculation (optional)
137 * - this can be used instead of calling key_payload_reserve(), that
138 * function only needs to be called if the real datalen is different
139 */
140 size_t def_datalen;
141
142 /* instantiate a key of this type
143 * - this method should call key_payload_reserve() to determine if the
144 * user's quota will hold the payload
145 */
146 int (*instantiate)(struct key *key, const void *data, size_t datalen);
147
148 /* duplicate a key of this type (optional)
149 * - the source key will be locked against change
150 * - the new description will be attached
151 * - the quota will have been adjusted automatically from
152 * source->quotalen
153 */
154 int (*duplicate)(struct key *key, const struct key *source);
155
156 /* update a key of this type (optional)
157 * - this method should call key_payload_reserve() to recalculate the
158 * quota consumption
159 * - the key must be locked against read when modifying
160 */
161 int (*update)(struct key *key, const void *data, size_t datalen);
162
163 /* match a key against a description */
164 int (*match)(const struct key *key, const void *desc);
165
166 /* clear the data from a key (optional) */
167 void (*destroy)(struct key *key);
168
169 /* describe a key */
170 void (*describe)(const struct key *key, struct seq_file *p);
171
172 /* read a key's data (optional)
173 * - permission checks will be done by the caller
174 * - the key's semaphore will be readlocked by the caller
175 * - should return the amount of data that could be read, no matter how
176 * much is copied into the buffer
177 * - shouldn't do the copy if the buffer is NULL
178 */
179 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
180
181 /* internal fields */
182 struct list_head link; /* link in types list */
183 };
184
185 extern struct key_type key_type_keyring;
186
187 extern int register_key_type(struct key_type *ktype);
188 extern void unregister_key_type(struct key_type *ktype);
189
190 extern struct key *key_alloc(struct key_type *type,
191 const char *desc,
192 uid_t uid, gid_t gid, key_perm_t perm,
193 int not_in_quota);
194 extern int key_payload_reserve(struct key *key, size_t datalen);
195 extern int key_instantiate_and_link(struct key *key,
196 const void *data,
197 size_t datalen,
198 struct key *keyring);
199 extern int key_negate_and_link(struct key *key,
200 unsigned timeout,
201 struct key *keyring);
202 extern void key_revoke(struct key *key);
203 extern void key_put(struct key *key);
204
205 static inline struct key *key_get(struct key *key)
206 {
207 if (key)
208 atomic_inc(&key->usage);
209 return key;
210 }
211
212 extern struct key *request_key(struct key_type *type,
213 const char *description,
214 const char *callout_info);
215
216 extern int key_validate(struct key *key);
217
218 extern struct key *key_create_or_update(struct key *keyring,
219 const char *type,
220 const char *description,
221 const void *payload,
222 size_t plen,
223 int not_in_quota);
224
225 extern int key_update(struct key *key,
226 const void *payload,
227 size_t plen);
228
229 extern int key_link(struct key *keyring,
230 struct key *key);
231
232 extern int key_unlink(struct key *keyring,
233 struct key *key);
234
235 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
236 int not_in_quota, struct key *dest);
237
238 extern int keyring_clear(struct key *keyring);
239
240 extern struct key *keyring_search(struct key *keyring,
241 struct key_type *type,
242 const char *description);
243
244 extern struct key *search_process_keyrings(struct key_type *type,
245 const char *description);
246
247 extern int keyring_add_key(struct key *keyring,
248 struct key *key);
249
250 extern struct key *key_lookup(key_serial_t id);
251
252 #define key_serial(key) ((key) ? (key)->serial : 0)
253
254 /*
255 * the userspace interface
256 */
257 extern struct key root_user_keyring, root_session_keyring;
258 extern int alloc_uid_keyring(struct user_struct *user);
259 extern void switch_uid_keyring(struct user_struct *new_user);
260 extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
261 extern void exit_keys(struct task_struct *tsk);
262 extern int suid_keys(struct task_struct *tsk);
263 extern int exec_keys(struct task_struct *tsk);
264 extern void key_fsuid_changed(struct task_struct *tsk);
265 extern void key_fsgid_changed(struct task_struct *tsk);
266 extern void key_init(void);
267
268 #else /* CONFIG_KEYS */
269
270 #define key_validate(k) 0
271 #define key_serial(k) 0
272 #define key_get(k) NULL
273 #define key_put(k) do { } while(0)
274 #define alloc_uid_keyring(u) 0
275 #define switch_uid_keyring(u) do { } while(0)
276 #define copy_keys(f,t) 0
277 #define exit_keys(t) do { } while(0)
278 #define suid_keys(t) do { } while(0)
279 #define exec_keys(t) do { } while(0)
280 #define key_fsuid_changed(t) do { } while(0)
281 #define key_fsgid_changed(t) do { } while(0)
282 #define key_init() do { } while(0)
283
284 #endif /* CONFIG_KEYS */
285 #endif /* __KERNEL__ */
286 #endif /* _LINUX_KEY_H */
287
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