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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 */
43#define KEY_POS_ALL 0x1f000000
44
45#define KEY_USR_VIEW 0x00010000 /* user permissions... */
46#define KEY_USR_READ 0x00020000
47#define KEY_USR_WRITE 0x00040000
48#define KEY_USR_SEARCH 0x00080000
49#define KEY_USR_LINK 0x00100000
Linus Torvalds1da177e2005-04-16 15:20:36 -070050#define KEY_USR_ALL 0x001f0000
51
52#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
53#define KEY_GRP_READ 0x00000200
54#define KEY_GRP_WRITE 0x00000400
55#define KEY_GRP_SEARCH 0x00000800
56#define KEY_GRP_LINK 0x00001000
57#define KEY_GRP_ALL 0x00001f00
58
59#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
60#define KEY_OTH_READ 0x00000002
61#define KEY_OTH_WRITE 0x00000004
62#define KEY_OTH_SEARCH 0x00000008
63#define KEY_OTH_LINK 0x00000010
64#define KEY_OTH_ALL 0x0000001f
65
66struct seq_file;
67struct user_struct;
68struct signal_struct;
69
70struct key_type;
71struct key_owner;
72struct keyring_list;
73struct keyring_name;
74
75/*****************************************************************************/
76/*
David Howells664cceb2005-09-28 17:03:15 +010077 * key reference with possession attribute handling
78 *
79 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
80 * defined. This is because we abuse the bottom bit of the reference to carry a
81 * flag to indicate whether the calling process possesses that key in one of
82 * its keyrings.
83 *
84 * the key_ref_t has been made a separate type so that the compiler can reject
85 * attempts to dereference it without proper conversion.
86 *
87 * the three functions are used to assemble and disassemble references
88 */
89typedef struct __key_reference_with_attributes *key_ref_t;
90
91static inline key_ref_t make_key_ref(const struct key *key,
92 unsigned long possession)
93{
94 return (key_ref_t) ((unsigned long) key | possession);
95}
96
97static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
98{
99 return (struct key *) ((unsigned long) key_ref & ~1UL);
100}
101
102static inline unsigned long is_key_possessed(const key_ref_t key_ref)
103{
104 return (unsigned long) key_ref & 1UL;
105}
106
107/*****************************************************************************/
108/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 * authentication token / access credential / keyring
110 * - types of key include:
111 * - keyrings
112 * - disk encryption IDs
113 * - Kerberos TGTs and tickets
114 */
115struct key {
116 atomic_t usage; /* number of references */
117 key_serial_t serial; /* key serial number */
118 struct rb_node serial_node;
119 struct key_type *type; /* type of key */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120 struct rw_semaphore sem; /* change vs change sem */
121 struct key_user *user; /* owner of this key */
122 time_t expiry; /* time at which key expires (or 0) */
123 uid_t uid;
124 gid_t gid;
125 key_perm_t perm; /* access permissions */
126 unsigned short quotalen; /* length added to quota */
David Howells76d8aea2005-06-23 22:00:49 -0700127 unsigned short datalen; /* payload data length
128 * - may not match RCU dereferenced payload
129 * - payload should contain own length
130 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131
132#ifdef KEY_DEBUGGING
133 unsigned magic;
134#define KEY_DEBUG_MAGIC 0x18273645u
135#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
136#endif
137
David Howells76d8aea2005-06-23 22:00:49 -0700138 unsigned long flags; /* status flags (change with bitops) */
139#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
140#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
141#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
142#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
143#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
144#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 /* the description string
147 * - this is used to match a key against search criteria
148 * - this should be a printable string
149 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
150 */
151 char *description;
152
153 /* type specific data
154 * - this is used by the keyring type to index the name
155 */
156 union {
157 struct list_head link;
158 } type_data;
159
160 /* key data
161 * - this is used to hold the data actually used in cryptography or
162 * whatever
163 */
164 union {
165 unsigned long value;
166 void *data;
167 struct keyring_list *subscriptions;
168 } payload;
169};
170
171/*****************************************************************************/
172/*
173 * kernel managed key type definition
174 */
175struct key_type {
176 /* name of the type */
177 const char *name;
178
179 /* default payload length for quota precalculation (optional)
180 * - this can be used instead of calling key_payload_reserve(), that
181 * function only needs to be called if the real datalen is different
182 */
183 size_t def_datalen;
184
185 /* instantiate a key of this type
186 * - this method should call key_payload_reserve() to determine if the
187 * user's quota will hold the payload
188 */
189 int (*instantiate)(struct key *key, const void *data, size_t datalen);
190
191 /* duplicate a key of this type (optional)
192 * - the source key will be locked against change
193 * - the new description will be attached
194 * - the quota will have been adjusted automatically from
195 * source->quotalen
196 */
197 int (*duplicate)(struct key *key, const struct key *source);
198
199 /* update a key of this type (optional)
200 * - this method should call key_payload_reserve() to recalculate the
201 * quota consumption
202 * - the key must be locked against read when modifying
203 */
204 int (*update)(struct key *key, const void *data, size_t datalen);
205
206 /* match a key against a description */
207 int (*match)(const struct key *key, const void *desc);
208
209 /* clear the data from a key (optional) */
210 void (*destroy)(struct key *key);
211
212 /* describe a key */
213 void (*describe)(const struct key *key, struct seq_file *p);
214
215 /* read a key's data (optional)
216 * - permission checks will be done by the caller
217 * - the key's semaphore will be readlocked by the caller
218 * - should return the amount of data that could be read, no matter how
219 * much is copied into the buffer
220 * - shouldn't do the copy if the buffer is NULL
221 */
222 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
223
224 /* internal fields */
225 struct list_head link; /* link in types list */
226};
227
228extern struct key_type key_type_keyring;
229
230extern int register_key_type(struct key_type *ktype);
231extern void unregister_key_type(struct key_type *ktype);
232
233extern struct key *key_alloc(struct key_type *type,
234 const char *desc,
235 uid_t uid, gid_t gid, key_perm_t perm,
236 int not_in_quota);
237extern int key_payload_reserve(struct key *key, size_t datalen);
238extern int key_instantiate_and_link(struct key *key,
239 const void *data,
240 size_t datalen,
David Howells3e301482005-06-23 22:00:56 -0700241 struct key *keyring,
242 struct key *instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700243extern int key_negate_and_link(struct key *key,
244 unsigned timeout,
David Howells3e301482005-06-23 22:00:56 -0700245 struct key *keyring,
246 struct key *instkey);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700247extern void key_revoke(struct key *key);
248extern void key_put(struct key *key);
249
250static inline struct key *key_get(struct key *key)
251{
252 if (key)
253 atomic_inc(&key->usage);
254 return key;
255}
256
David Howells664cceb2005-09-28 17:03:15 +0100257static inline void key_ref_put(key_ref_t key_ref)
258{
259 key_put(key_ref_to_ptr(key_ref));
260}
261
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262extern struct key *request_key(struct key_type *type,
263 const char *description,
264 const char *callout_info);
265
266extern int key_validate(struct key *key);
267
David Howells664cceb2005-09-28 17:03:15 +0100268extern key_ref_t key_create_or_update(key_ref_t keyring,
269 const char *type,
270 const char *description,
271 const void *payload,
272 size_t plen,
273 int not_in_quota);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274
David Howells664cceb2005-09-28 17:03:15 +0100275extern int key_update(key_ref_t key,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276 const void *payload,
277 size_t plen);
278
279extern int key_link(struct key *keyring,
280 struct key *key);
281
282extern int key_unlink(struct key *keyring,
283 struct key *key);
284
285extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
286 int not_in_quota, struct key *dest);
287
288extern int keyring_clear(struct key *keyring);
289
David Howells664cceb2005-09-28 17:03:15 +0100290extern key_ref_t keyring_search(key_ref_t keyring,
291 struct key_type *type,
292 const char *description);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294extern int keyring_add_key(struct key *keyring,
295 struct key *key);
296
297extern struct key *key_lookup(key_serial_t id);
298
David Howells76d8aea2005-06-23 22:00:49 -0700299extern void keyring_replace_payload(struct key *key, void *replacement);
300
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301#define key_serial(key) ((key) ? (key)->serial : 0)
302
303/*
304 * the userspace interface
305 */
306extern struct key root_user_keyring, root_session_keyring;
307extern int alloc_uid_keyring(struct user_struct *user);
308extern void switch_uid_keyring(struct user_struct *new_user);
309extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
310extern int copy_thread_group_keys(struct task_struct *tsk);
311extern void exit_keys(struct task_struct *tsk);
312extern void exit_thread_group_keys(struct signal_struct *tg);
313extern int suid_keys(struct task_struct *tsk);
314extern int exec_keys(struct task_struct *tsk);
315extern void key_fsuid_changed(struct task_struct *tsk);
316extern void key_fsgid_changed(struct task_struct *tsk);
317extern void key_init(void);
318
David Howells7888e7f2005-06-23 22:00:51 -0700319#define __install_session_keyring(tsk, keyring) \
320({ \
321 struct key *old_session = tsk->signal->session_keyring; \
322 tsk->signal->session_keyring = keyring; \
323 old_session; \
324})
325
Linus Torvalds1da177e2005-04-16 15:20:36 -0700326#else /* CONFIG_KEYS */
327
328#define key_validate(k) 0
329#define key_serial(k) 0
David Howells7888e7f2005-06-23 22:00:51 -0700330#define key_get(k) ({ NULL; })
Linus Torvalds1da177e2005-04-16 15:20:36 -0700331#define key_put(k) do { } while(0)
David Howells664cceb2005-09-28 17:03:15 +0100332#define key_ref_put(k) do { } while(0)
333#define make_key_ref(k) ({ NULL; })
334#define key_ref_to_ptr(k) ({ NULL; })
335#define is_key_possessed(k) 0
Linus Torvalds1da177e2005-04-16 15:20:36 -0700336#define alloc_uid_keyring(u) 0
337#define switch_uid_keyring(u) do { } while(0)
David Howells7888e7f2005-06-23 22:00:51 -0700338#define __install_session_keyring(t, k) ({ NULL; })
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339#define copy_keys(f,t) 0
340#define copy_thread_group_keys(t) 0
341#define exit_keys(t) do { } while(0)
342#define exit_thread_group_keys(tg) do { } while(0)
343#define suid_keys(t) do { } while(0)
344#define exec_keys(t) do { } while(0)
345#define key_fsuid_changed(t) do { } while(0)
346#define key_fsgid_changed(t) do { } while(0)
347#define key_init() do { } while(0)
348
349#endif /* CONFIG_KEYS */
350#endif /* __KERNEL__ */
351#endif /* _LINUX_KEY_H */