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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/spinlock.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 rwlock_t lock; /* examination vs change lock */
82 struct rw_semaphore sem; /* change vs change sem */
83 struct key_user *user; /* owner of this key */
84 time_t expiry; /* time at which key expires (or 0) */
85 uid_t uid;
86 gid_t gid;
87 key_perm_t perm; /* access permissions */
88 unsigned short quotalen; /* length added to quota */
89 unsigned short datalen; /* payload data length */
90 unsigned short flags; /* status flags (change with lock writelocked) */
91#define KEY_FLAG_INSTANTIATED 0x00000001 /* set if key has been instantiated */
92#define KEY_FLAG_DEAD 0x00000002 /* set if key type has been deleted */
93#define KEY_FLAG_REVOKED 0x00000004 /* set if key had been revoked */
94#define KEY_FLAG_IN_QUOTA 0x00000008 /* set if key consumes quota */
95#define KEY_FLAG_USER_CONSTRUCT 0x00000010 /* set if key is being constructed in userspace */
96#define KEY_FLAG_NEGATIVE 0x00000020 /* set if key is negative */
97
98#ifdef KEY_DEBUGGING
99 unsigned magic;
100#define KEY_DEBUG_MAGIC 0x18273645u
101#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
102#endif
103
104 /* the description string
105 * - this is used to match a key against search criteria
106 * - this should be a printable string
107 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
108 */
109 char *description;
110
111 /* type specific data
112 * - this is used by the keyring type to index the name
113 */
114 union {
115 struct list_head link;
116 } type_data;
117
118 /* key data
119 * - this is used to hold the data actually used in cryptography or
120 * whatever
121 */
122 union {
123 unsigned long value;
124 void *data;
125 struct keyring_list *subscriptions;
126 } payload;
127};
128
129/*****************************************************************************/
130/*
131 * kernel managed key type definition
132 */
133struct key_type {
134 /* name of the type */
135 const char *name;
136
137 /* default payload length for quota precalculation (optional)
138 * - this can be used instead of calling key_payload_reserve(), that
139 * function only needs to be called if the real datalen is different
140 */
141 size_t def_datalen;
142
143 /* instantiate a key of this type
144 * - this method should call key_payload_reserve() to determine if the
145 * user's quota will hold the payload
146 */
147 int (*instantiate)(struct key *key, const void *data, size_t datalen);
148
149 /* duplicate a key of this type (optional)
150 * - the source key will be locked against change
151 * - the new description will be attached
152 * - the quota will have been adjusted automatically from
153 * source->quotalen
154 */
155 int (*duplicate)(struct key *key, const struct key *source);
156
157 /* update a key of this type (optional)
158 * - this method should call key_payload_reserve() to recalculate the
159 * quota consumption
160 * - the key must be locked against read when modifying
161 */
162 int (*update)(struct key *key, const void *data, size_t datalen);
163
164 /* match a key against a description */
165 int (*match)(const struct key *key, const void *desc);
166
167 /* clear the data from a key (optional) */
168 void (*destroy)(struct key *key);
169
170 /* describe a key */
171 void (*describe)(const struct key *key, struct seq_file *p);
172
173 /* read a key's data (optional)
174 * - permission checks will be done by the caller
175 * - the key's semaphore will be readlocked by the caller
176 * - should return the amount of data that could be read, no matter how
177 * much is copied into the buffer
178 * - shouldn't do the copy if the buffer is NULL
179 */
180 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
181
182 /* internal fields */
183 struct list_head link; /* link in types list */
184};
185
186extern struct key_type key_type_keyring;
187
188extern int register_key_type(struct key_type *ktype);
189extern void unregister_key_type(struct key_type *ktype);
190
191extern struct key *key_alloc(struct key_type *type,
192 const char *desc,
193 uid_t uid, gid_t gid, key_perm_t perm,
194 int not_in_quota);
195extern int key_payload_reserve(struct key *key, size_t datalen);
196extern int key_instantiate_and_link(struct key *key,
197 const void *data,
198 size_t datalen,
199 struct key *keyring);
200extern int key_negate_and_link(struct key *key,
201 unsigned timeout,
202 struct key *keyring);
203extern void key_revoke(struct key *key);
204extern void key_put(struct key *key);
205
206static inline struct key *key_get(struct key *key)
207{
208 if (key)
209 atomic_inc(&key->usage);
210 return key;
211}
212
213extern struct key *request_key(struct key_type *type,
214 const char *description,
215 const char *callout_info);
216
217extern int key_validate(struct key *key);
218
219extern struct key *key_create_or_update(struct key *keyring,
220 const char *type,
221 const char *description,
222 const void *payload,
223 size_t plen,
224 int not_in_quota);
225
226extern int key_update(struct key *key,
227 const void *payload,
228 size_t plen);
229
230extern int key_link(struct key *keyring,
231 struct key *key);
232
233extern int key_unlink(struct key *keyring,
234 struct key *key);
235
236extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
237 int not_in_quota, struct key *dest);
238
239extern int keyring_clear(struct key *keyring);
240
241extern struct key *keyring_search(struct key *keyring,
242 struct key_type *type,
243 const char *description);
244
245extern struct key *search_process_keyrings(struct key_type *type,
246 const char *description);
247
248extern int keyring_add_key(struct key *keyring,
249 struct key *key);
250
251extern struct key *key_lookup(key_serial_t id);
252
253#define key_serial(key) ((key) ? (key)->serial : 0)
254
255/*
256 * the userspace interface
257 */
258extern struct key root_user_keyring, root_session_keyring;
259extern int alloc_uid_keyring(struct user_struct *user);
260extern void switch_uid_keyring(struct user_struct *new_user);
261extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
262extern int copy_thread_group_keys(struct task_struct *tsk);
263extern void exit_keys(struct task_struct *tsk);
264extern void exit_thread_group_keys(struct signal_struct *tg);
265extern int suid_keys(struct task_struct *tsk);
266extern int exec_keys(struct task_struct *tsk);
267extern void key_fsuid_changed(struct task_struct *tsk);
268extern void key_fsgid_changed(struct task_struct *tsk);
269extern void key_init(void);
270
271#else /* CONFIG_KEYS */
272
273#define key_validate(k) 0
274#define key_serial(k) 0
275#define key_get(k) NULL
276#define key_put(k) do { } while(0)
277#define alloc_uid_keyring(u) 0
278#define switch_uid_keyring(u) do { } while(0)
279#define copy_keys(f,t) 0
280#define copy_thread_group_keys(t) 0
281#define exit_keys(t) do { } while(0)
282#define exit_thread_group_keys(tg) do { } while(0)
283#define suid_keys(t) do { } while(0)
284#define exec_keys(t) do { } while(0)
285#define key_fsuid_changed(t) do { } while(0)
286#define key_fsgid_changed(t) do { } while(0)
287#define key_init() do { } while(0)
288
289#endif /* CONFIG_KEYS */
290#endif /* __KERNEL__ */
291#endif /* _LINUX_KEY_H */