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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* 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>
David Howells76d8aea2005-06-23 22:00:49 -070021#include <linux/rcupdate.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#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
David Howells664cceb2005-09-28 17:03:15 +010038#define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
39#define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
40#define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
41#define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
42#define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
David Howells29db9192005-10-30 15:02:44 -080043#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
44#define KEY_POS_ALL 0x3f000000
David Howells664cceb2005-09-28 17:03:15 +010045
46#define KEY_USR_VIEW 0x00010000 /* user permissions... */
47#define KEY_USR_READ 0x00020000
48#define KEY_USR_WRITE 0x00040000
49#define KEY_USR_SEARCH 0x00080000
50#define KEY_USR_LINK 0x00100000
David Howells29db9192005-10-30 15:02:44 -080051#define KEY_USR_SETATTR 0x00200000
52#define KEY_USR_ALL 0x003f0000
Linus Torvalds1da177e2005-04-16 15:20:36 -070053
54#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
55#define KEY_GRP_READ 0x00000200
56#define KEY_GRP_WRITE 0x00000400
57#define KEY_GRP_SEARCH 0x00000800
58#define KEY_GRP_LINK 0x00001000
David Howells29db9192005-10-30 15:02:44 -080059#define KEY_GRP_SETATTR 0x00002000
60#define KEY_GRP_ALL 0x00003f00
Linus Torvalds1da177e2005-04-16 15:20:36 -070061
62#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
63#define KEY_OTH_READ 0x00000002
64#define KEY_OTH_WRITE 0x00000004
65#define KEY_OTH_SEARCH 0x00000008
66#define KEY_OTH_LINK 0x00000010
David Howells29db9192005-10-30 15:02:44 -080067#define KEY_OTH_SETATTR 0x00000020
68#define KEY_OTH_ALL 0x0000003f
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
70struct seq_file;
71struct user_struct;
72struct signal_struct;
73
74struct key_type;
75struct key_owner;
76struct keyring_list;
77struct keyring_name;
78
79/*****************************************************************************/
80/*
David Howells664cceb2005-09-28 17:03:15 +010081 * key reference with possession attribute handling
82 *
83 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
84 * defined. This is because we abuse the bottom bit of the reference to carry a
85 * flag to indicate whether the calling process possesses that key in one of
86 * its keyrings.
87 *
88 * the key_ref_t has been made a separate type so that the compiler can reject
89 * attempts to dereference it without proper conversion.
90 *
91 * the three functions are used to assemble and disassemble references
92 */
93typedef struct __key_reference_with_attributes *key_ref_t;
94
95static inline key_ref_t make_key_ref(const struct key *key,
96 unsigned long possession)
97{
98 return (key_ref_t) ((unsigned long) key | possession);
99}
100
101static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
102{
103 return (struct key *) ((unsigned long) key_ref & ~1UL);
104}
105
106static inline unsigned long is_key_possessed(const key_ref_t key_ref)
107{
108 return (unsigned long) key_ref & 1UL;
109}
110
111/*****************************************************************************/
112/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113 * authentication token / access credential / keyring
114 * - types of key include:
115 * - keyrings
116 * - disk encryption IDs
117 * - Kerberos TGTs and tickets
118 */
119struct key {
120 atomic_t usage; /* number of references */
121 key_serial_t serial; /* key serial number */
122 struct rb_node serial_node;
123 struct key_type *type; /* type of key */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124 struct rw_semaphore sem; /* change vs change sem */
125 struct key_user *user; /* owner of this key */
David Howells29db9192005-10-30 15:02:44 -0800126 void *security; /* security data for this key */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 time_t expiry; /* time at which key expires (or 0) */
128 uid_t uid;
129 gid_t gid;
130 key_perm_t perm; /* access permissions */
131 unsigned short quotalen; /* length added to quota */
David Howells76d8aea2005-06-23 22:00:49 -0700132 unsigned short datalen; /* payload data length
133 * - may not match RCU dereferenced payload
134 * - payload should contain own length
135 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136
137#ifdef KEY_DEBUGGING
138 unsigned magic;
139#define KEY_DEBUG_MAGIC 0x18273645u
140#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
141#endif
142
David Howells76d8aea2005-06-23 22:00:49 -0700143 unsigned long flags; /* status flags (change with bitops) */
144#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
145#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
146#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
147#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
148#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
149#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
150
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151 /* the description string
152 * - this is used to match a key against search criteria
153 * - this should be a printable string
154 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
155 */
156 char *description;
157
158 /* type specific data
159 * - this is used by the keyring type to index the name
160 */
161 union {
162 struct list_head link;
163 } type_data;
164
165 /* key data
166 * - this is used to hold the data actually used in cryptography or
167 * whatever
168 */
169 union {
170 unsigned long value;
171 void *data;
172 struct keyring_list *subscriptions;
173 } payload;
174};
175
176/*****************************************************************************/
177/*
178 * kernel managed key type definition
179 */
180struct key_type {
181 /* name of the type */
182 const char *name;
183
184 /* default payload length for quota precalculation (optional)
185 * - this can be used instead of calling key_payload_reserve(), that
186 * function only needs to be called if the real datalen is different
187 */
188 size_t def_datalen;
189
190 /* instantiate a key of this type
191 * - this method should call key_payload_reserve() to determine if the
192 * user's quota will hold the payload
193 */
194 int (*instantiate)(struct key *key, const void *data, size_t datalen);
195
196 /* duplicate a key of this type (optional)
197 * - the source key will be locked against change
198 * - the new description will be attached
199 * - the quota will have been adjusted automatically from
200 * source->quotalen
201 */
202 int (*duplicate)(struct key *key, const struct key *source);
203
204 /* update a key of this type (optional)
205 * - this method should call key_payload_reserve() to recalculate the
206 * quota consumption
207 * - the key must be locked against read when modifying
208 */
209 int (*update)(struct key *key, const void *data, size_t datalen);
210
211 /* match a key against a description */
212 int (*match)(const struct key *key, const void *desc);
213
214 /* clear the data from a key (optional) */
215 void (*destroy)(struct key *key);
216
217 /* describe a key */
218 void (*describe)(const struct key *key, struct seq_file *p);
219
220 /* read a key's data (optional)
221 * - permission checks will be done by the caller
222 * - the key's semaphore will be readlocked by the caller
223 * - should return the amount of data that could be read, no matter how
224 * much is copied into the buffer
225 * - shouldn't do the copy if the buffer is NULL
226 */
227 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
228
229 /* internal fields */
230 struct list_head link; /* link in types list */
231};
232
233extern struct key_type key_type_keyring;
234
235extern int register_key_type(struct key_type *ktype);
236extern void unregister_key_type(struct key_type *ktype);
237
238extern struct key *key_alloc(struct key_type *type,
239 const char *desc,
240 uid_t uid, gid_t gid, key_perm_t perm,
241 int not_in_quota);
242extern int key_payload_reserve(struct key *key, size_t datalen);
243extern int key_instantiate_and_link(struct key *key,
244 const void *data,
245 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700246 struct key *keyring,
247 struct key *instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700248extern int key_negate_and_link(struct key *key,
249 unsigned timeout,
David Howells3e301482005-06-23 22:00:56 -0700250 struct key *keyring,
251 struct key *instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700252extern void key_revoke(struct key *key);
253extern void key_put(struct key *key);
254
255static inline struct key *key_get(struct key *key)
256{
257 if (key)
258 atomic_inc(&key->usage);
259 return key;
260}
261
David Howells664cceb2005-09-28 17:03:15 +0100262static inline void key_ref_put(key_ref_t key_ref)
263{
264 key_put(key_ref_to_ptr(key_ref));
265}
266
Linus Torvalds1da177e2005-04-16 15:20:36 -0700267extern struct key *request_key(struct key_type *type,
268 const char *description,
269 const char *callout_info);
270
271extern int key_validate(struct key *key);
272
David Howells664cceb2005-09-28 17:03:15 +0100273extern key_ref_t key_create_or_update(key_ref_t keyring,
274 const char *type,
275 const char *description,
276 const void *payload,
277 size_t plen,
278 int not_in_quota);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
David Howells664cceb2005-09-28 17:03:15 +0100280extern int key_update(key_ref_t key,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 const void *payload,
282 size_t plen);
283
284extern int key_link(struct key *keyring,
285 struct key *key);
286
287extern int key_unlink(struct key *keyring,
288 struct key *key);
289
290extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
291 int not_in_quota, struct key *dest);
292
293extern int keyring_clear(struct key *keyring);
294
David Howells664cceb2005-09-28 17:03:15 +0100295extern key_ref_t keyring_search(key_ref_t keyring,
296 struct key_type *type,
297 const char *description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299extern int keyring_add_key(struct key *keyring,
300 struct key *key);
301
302extern struct key *key_lookup(key_serial_t id);
303
David Howells76d8aea2005-06-23 22:00:49 -0700304extern void keyring_replace_payload(struct key *key, void *replacement);
305
Linus Torvalds1da177e2005-04-16 15:20:36 -0700306#define key_serial(key) ((key) ? (key)->serial : 0)
307
308/*
309 * the userspace interface
310 */
311extern struct key root_user_keyring, root_session_keyring;
312extern int alloc_uid_keyring(struct user_struct *user);
313extern void switch_uid_keyring(struct user_struct *new_user);
314extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
315extern int copy_thread_group_keys(struct task_struct *tsk);
316extern void exit_keys(struct task_struct *tsk);
317extern void exit_thread_group_keys(struct signal_struct *tg);
318extern int suid_keys(struct task_struct *tsk);
319extern int exec_keys(struct task_struct *tsk);
320extern void key_fsuid_changed(struct task_struct *tsk);
321extern void key_fsgid_changed(struct task_struct *tsk);
322extern void key_init(void);
323
David Howells7888e7f2005-06-23 22:00:51 -0700324#define __install_session_keyring(tsk, keyring) \
325({ \
326 struct key *old_session = tsk->signal->session_keyring; \
327 tsk->signal->session_keyring = keyring; \
328 old_session; \
329})
330
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331#else /* CONFIG_KEYS */
332
333#define key_validate(k) 0
334#define key_serial(k) 0
David Howells7888e7f2005-06-23 22:00:51 -0700335#define key_get(k) ({ NULL; })
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336#define key_put(k) do { } while(0)
David Howells664cceb2005-09-28 17:03:15 +0100337#define key_ref_put(k) do { } while(0)
338#define make_key_ref(k) ({ NULL; })
339#define key_ref_to_ptr(k) ({ NULL; })
340#define is_key_possessed(k) 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341#define alloc_uid_keyring(u) 0
342#define switch_uid_keyring(u) do { } while(0)
David Howells7888e7f2005-06-23 22:00:51 -0700343#define __install_session_keyring(t, k) ({ NULL; })
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344#define copy_keys(f,t) 0
345#define copy_thread_group_keys(t) 0
346#define exit_keys(t) do { } while(0)
347#define exit_thread_group_keys(tg) do { } while(0)
348#define suid_keys(t) do { } while(0)
349#define exec_keys(t) do { } while(0)
350#define key_fsuid_changed(t) do { } while(0)
351#define key_fsgid_changed(t) do { } while(0)
352#define key_init() do { } while(0)
353
354#endif /* CONFIG_KEYS */
355#endif /* __KERNEL__ */
356#endif /* _LINUX_KEY_H */