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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/rcupdate.h>
22#include <asm/atomic.h>
23
24#ifdef __KERNEL__
25
26/* key handle serial number */
27typedef int32_t key_serial_t;
28
29/* key handle permissions mask */
30typedef uint32_t key_perm_t;
31
32struct 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
59struct seq_file;
60struct user_struct;
61struct signal_struct;
62
63struct key_type;
64struct key_owner;
65struct keyring_list;
66struct keyring_name;
67
68/*****************************************************************************/
69/*
70 * authentication token / access credential / keyring
71 * - types of key include:
72 * - keyrings
73 * - disk encryption IDs
74 * - Kerberos TGTs and tickets
75 */
76struct key {
77 atomic_t usage; /* number of references */
78 key_serial_t serial; /* key serial number */
79 struct rb_node serial_node;
80 struct key_type *type; /* type of key */
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 * - may not match RCU dereferenced payload
90 * - payload should contain own length
91 */
92
93#ifdef KEY_DEBUGGING
94 unsigned magic;
95#define KEY_DEBUG_MAGIC 0x18273645u
96#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
97#endif
98
99 unsigned long flags; /* status flags (change with bitops) */
100#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
101#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
102#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
103#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
104#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
105#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
106
107 /* the description string
108 * - this is used to match a key against search criteria
109 * - this should be a printable string
110 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
111 */
112 char *description;
113
114 /* type specific data
115 * - this is used by the keyring type to index the name
116 */
117 union {
118 struct list_head link;
119 } type_data;
120
121 /* key data
122 * - this is used to hold the data actually used in cryptography or
123 * whatever
124 */
125 union {
126 unsigned long value;
127 void *data;
128 struct keyring_list *subscriptions;
129 } payload;
130};
131
132/*****************************************************************************/
133/*
134 * kernel managed key type definition
135 */
136struct key_type {
137 /* name of the type */
138 const char *name;
139
140 /* default payload length for quota precalculation (optional)
141 * - this can be used instead of calling key_payload_reserve(), that
142 * function only needs to be called if the real datalen is different
143 */
144 size_t def_datalen;
145
146 /* instantiate a key of this type
147 * - this method should call key_payload_reserve() to determine if the
148 * user's quota will hold the payload
149 */
150 int (*instantiate)(struct key *key, const void *data, size_t datalen);
151
152 /* duplicate a key of this type (optional)
153 * - the source key will be locked against change
154 * - the new description will be attached
155 * - the quota will have been adjusted automatically from
156 * source->quotalen
157 */
158 int (*duplicate)(struct key *key, const struct key *source);
159
160 /* update a key of this type (optional)
161 * - this method should call key_payload_reserve() to recalculate the
162 * quota consumption
163 * - the key must be locked against read when modifying
164 */
165 int (*update)(struct key *key, const void *data, size_t datalen);
166
167 /* match a key against a description */
168 int (*match)(const struct key *key, const void *desc);
169
170 /* clear the data from a key (optional) */
171 void (*destroy)(struct key *key);
172
173 /* describe a key */
174 void (*describe)(const struct key *key, struct seq_file *p);
175
176 /* read a key's data (optional)
177 * - permission checks will be done by the caller
178 * - the key's semaphore will be readlocked by the caller
179 * - should return the amount of data that could be read, no matter how
180 * much is copied into the buffer
181 * - shouldn't do the copy if the buffer is NULL
182 */
183 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
184
185 /* internal fields */
186 struct list_head link; /* link in types list */
187};
188
189extern struct key_type key_type_keyring;
190
191extern int register_key_type(struct key_type *ktype);
192extern void unregister_key_type(struct key_type *ktype);
193
194extern struct key *key_alloc(struct key_type *type,
195 const char *desc,
196 uid_t uid, gid_t gid, key_perm_t perm,
197 int not_in_quota);
198extern int key_payload_reserve(struct key *key, size_t datalen);
199extern int key_instantiate_and_link(struct key *key,
200 const void *data,
201 size_t datalen,
202 struct key *keyring,
203 struct key *instkey);
204extern int key_negate_and_link(struct key *key,
205 unsigned timeout,
206 struct key *keyring,
207 struct key *instkey);
208extern void key_revoke(struct key *key);
209extern void key_put(struct key *key);
210
211static inline struct key *key_get(struct key *key)
212{
213 if (key)
214 atomic_inc(&key->usage);
215 return key;
216}
217
218extern struct key *request_key(struct key_type *type,
219 const char *description,
220 const char *callout_info);
221
222extern int key_validate(struct key *key);
223
224extern struct key *key_create_or_update(struct key *keyring,
225 const char *type,
226 const char *description,
227 const void *payload,
228 size_t plen,
229 int not_in_quota);
230
231extern int key_update(struct key *key,
232 const void *payload,
233 size_t plen);
234
235extern int key_link(struct key *keyring,
236 struct key *key);
237
238extern int key_unlink(struct key *keyring,
239 struct key *key);
240
241extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
242 int not_in_quota, struct key *dest);
243
244extern int keyring_clear(struct key *keyring);
245
246extern struct key *keyring_search(struct key *keyring,
247 struct key_type *type,
248 const char *description);
249
250extern int keyring_add_key(struct key *keyring,
251 struct key *key);
252
253extern struct key *key_lookup(key_serial_t id);
254
255extern void keyring_replace_payload(struct key *key, void *replacement);
256
257#define key_serial(key) ((key) ? (key)->serial : 0)
258
259/*
260 * the userspace interface
261 */
262extern struct key root_user_keyring, root_session_keyring;
263extern int alloc_uid_keyring(struct user_struct *user);
264extern void switch_uid_keyring(struct user_struct *new_user);
265extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
266extern int copy_thread_group_keys(struct task_struct *tsk);
267extern void exit_keys(struct task_struct *tsk);
268extern void exit_thread_group_keys(struct signal_struct *tg);
269extern int suid_keys(struct task_struct *tsk);
270extern int exec_keys(struct task_struct *tsk);
271extern void key_fsuid_changed(struct task_struct *tsk);
272extern void key_fsgid_changed(struct task_struct *tsk);
273extern void key_init(void);
274
275#define __install_session_keyring(tsk, keyring) \
276({ \
277 struct key *old_session = tsk->signal->session_keyring; \
278 tsk->signal->session_keyring = keyring; \
279 old_session; \
280})
281
282#else /* CONFIG_KEYS */
283
284#define key_validate(k) 0
285#define key_serial(k) 0
286#define key_get(k) ({ NULL; })
287#define key_put(k) do { } while(0)
288#define alloc_uid_keyring(u) 0
289#define switch_uid_keyring(u) do { } while(0)
290#define __install_session_keyring(t, k) ({ NULL; })
291#define copy_keys(f,t) 0
292#define copy_thread_group_keys(t) 0
293#define exit_keys(t) do { } while(0)
294#define exit_thread_group_keys(tg) do { } while(0)
295#define suid_keys(t) do { } while(0)
296#define exec_keys(t) do { } while(0)
297#define key_fsuid_changed(t) do { } while(0)
298#define key_fsgid_changed(t) do { } while(0)
299#define key_init() do { } while(0)
300
301#endif /* CONFIG_KEYS */
302#endif /* __KERNEL__ */
303#endif /* _LINUX_KEY_H */