KEYS: Permit in-place link replacement in keyring list
[linux-2.6-block.git] / include / linux / key.h
CommitLineData
76181c13 1/* Authentication token and access key management
1da177e4 2 *
76181c13 3 * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
1da177e4
LT
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 *
d410fa4e 12 * See Documentation/security/keys.txt for information on keys/keyrings.
1da177e4
LT
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>
76d8aeab 21#include <linux/rcupdate.h>
0b77f5bf 22#include <linux/sysctl.h>
aa84442d 23#include <linux/rwsem.h>
60063497 24#include <linux/atomic.h>
1da177e4
LT
25
26#ifdef __KERNEL__
27
28/* key handle serial number */
29typedef int32_t key_serial_t;
30
31/* key handle permissions mask */
32typedef uint32_t key_perm_t;
33
34struct key;
35
36#ifdef CONFIG_KEYS
37
38#undef KEY_DEBUGGING
39
664cceb0
DH
40#define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
41#define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
42#define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
43#define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
44#define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
29db9190
DH
45#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
46#define KEY_POS_ALL 0x3f000000
664cceb0
DH
47
48#define KEY_USR_VIEW 0x00010000 /* user permissions... */
49#define KEY_USR_READ 0x00020000
50#define KEY_USR_WRITE 0x00040000
51#define KEY_USR_SEARCH 0x00080000
52#define KEY_USR_LINK 0x00100000
29db9190
DH
53#define KEY_USR_SETATTR 0x00200000
54#define KEY_USR_ALL 0x003f0000
1da177e4
LT
55
56#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
57#define KEY_GRP_READ 0x00000200
58#define KEY_GRP_WRITE 0x00000400
59#define KEY_GRP_SEARCH 0x00000800
60#define KEY_GRP_LINK 0x00001000
29db9190
DH
61#define KEY_GRP_SETATTR 0x00002000
62#define KEY_GRP_ALL 0x00003f00
1da177e4
LT
63
64#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
65#define KEY_OTH_READ 0x00000002
66#define KEY_OTH_WRITE 0x00000004
67#define KEY_OTH_SEARCH 0x00000008
68#define KEY_OTH_LINK 0x00000010
29db9190
DH
69#define KEY_OTH_SETATTR 0x00000020
70#define KEY_OTH_ALL 0x0000003f
1da177e4 71
6b79ccb5
AR
72#define KEY_PERM_UNDEF 0xffffffff
73
1da177e4
LT
74struct seq_file;
75struct user_struct;
76struct signal_struct;
d84f4f99 77struct cred;
1da177e4
LT
78
79struct key_type;
80struct key_owner;
81struct keyring_list;
82struct keyring_name;
83
664cceb0
DH
84/*****************************************************************************/
85/*
86 * key reference with possession attribute handling
87 *
88 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
89 * defined. This is because we abuse the bottom bit of the reference to carry a
90 * flag to indicate whether the calling process possesses that key in one of
91 * its keyrings.
92 *
93 * the key_ref_t has been made a separate type so that the compiler can reject
94 * attempts to dereference it without proper conversion.
95 *
96 * the three functions are used to assemble and disassemble references
97 */
98typedef struct __key_reference_with_attributes *key_ref_t;
99
100static inline key_ref_t make_key_ref(const struct key *key,
101 unsigned long possession)
102{
103 return (key_ref_t) ((unsigned long) key | possession);
104}
105
106static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
107{
108 return (struct key *) ((unsigned long) key_ref & ~1UL);
109}
110
111static inline unsigned long is_key_possessed(const key_ref_t key_ref)
112{
113 return (unsigned long) key_ref & 1UL;
114}
115
1da177e4
LT
116/*****************************************************************************/
117/*
118 * authentication token / access credential / keyring
119 * - types of key include:
120 * - keyrings
121 * - disk encryption IDs
122 * - Kerberos TGTs and tickets
123 */
124struct key {
125 atomic_t usage; /* number of references */
126 key_serial_t serial; /* key serial number */
65d87fe6
DH
127 union {
128 struct list_head graveyard_link;
129 struct rb_node serial_node;
130 };
1da177e4 131 struct key_type *type; /* type of key */
1da177e4
LT
132 struct rw_semaphore sem; /* change vs change sem */
133 struct key_user *user; /* owner of this key */
29db9190 134 void *security; /* security data for this key */
5d135440
DH
135 union {
136 time_t expiry; /* time at which key expires (or 0) */
137 time_t revoked_at; /* time at which key was revoked */
138 };
1da177e4
LT
139 uid_t uid;
140 gid_t gid;
141 key_perm_t perm; /* access permissions */
142 unsigned short quotalen; /* length added to quota */
76d8aeab
DH
143 unsigned short datalen; /* payload data length
144 * - may not match RCU dereferenced payload
145 * - payload should contain own length
146 */
1da177e4
LT
147
148#ifdef KEY_DEBUGGING
149 unsigned magic;
150#define KEY_DEBUG_MAGIC 0x18273645u
151#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
152#endif
153
76d8aeab
DH
154 unsigned long flags; /* status flags (change with bitops) */
155#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
156#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
157#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
158#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
159#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
160#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
700920eb 161#define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */
76d8aeab 162
1da177e4
LT
163 /* the description string
164 * - this is used to match a key against search criteria
165 * - this should be a printable string
166 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
167 */
168 char *description;
169
170 /* type specific data
171 * - this is used by the keyring type to index the name
172 */
173 union {
174 struct list_head link;
7318226e
DH
175 unsigned long x[2];
176 void *p[2];
fdd1b945 177 int reject_error;
1da177e4
LT
178 } type_data;
179
180 /* key data
181 * - this is used to hold the data actually used in cryptography or
182 * whatever
183 */
184 union {
185 unsigned long value;
e63ba744 186 void __rcu *rcudata;
1da177e4 187 void *data;
e63ba744 188 struct keyring_list __rcu *subscriptions;
1da177e4
LT
189 } payload;
190};
191
1da177e4
LT
192extern struct key *key_alloc(struct key_type *type,
193 const char *desc,
d720024e 194 uid_t uid, gid_t gid,
d84f4f99 195 const struct cred *cred,
7e047ef5
DH
196 key_perm_t perm,
197 unsigned long flags);
198
199
200#define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
201#define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
202#define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
203
1da177e4
LT
204extern void key_revoke(struct key *key);
205extern void key_put(struct key *key);
206
207static inline struct key *key_get(struct key *key)
208{
209 if (key)
210 atomic_inc(&key->usage);
211 return key;
212}
213
664cceb0
DH
214static inline void key_ref_put(key_ref_t key_ref)
215{
216 key_put(key_ref_to_ptr(key_ref));
217}
218
1da177e4
LT
219extern struct key *request_key(struct key_type *type,
220 const char *description,
221 const char *callout_info);
222
4e54f085
DH
223extern struct key *request_key_with_auxdata(struct key_type *type,
224 const char *description,
4a38e122
DH
225 const void *callout_info,
226 size_t callout_len,
4e54f085
DH
227 void *aux);
228
76181c13
DH
229extern struct key *request_key_async(struct key_type *type,
230 const char *description,
4a38e122
DH
231 const void *callout_info,
232 size_t callout_len);
76181c13
DH
233
234extern struct key *request_key_async_with_auxdata(struct key_type *type,
235 const char *description,
4a38e122
DH
236 const void *callout_info,
237 size_t callout_len,
76181c13
DH
238 void *aux);
239
240extern int wait_for_key_construction(struct key *key, bool intr);
241
1da177e4
LT
242extern int key_validate(struct key *key);
243
664cceb0
DH
244extern key_ref_t key_create_or_update(key_ref_t keyring,
245 const char *type,
246 const char *description,
247 const void *payload,
248 size_t plen,
6b79ccb5 249 key_perm_t perm,
7e047ef5 250 unsigned long flags);
1da177e4 251
664cceb0 252extern int key_update(key_ref_t key,
1da177e4
LT
253 const void *payload,
254 size_t plen);
255
256extern int key_link(struct key *keyring,
257 struct key *key);
258
259extern int key_unlink(struct key *keyring,
260 struct key *key);
261
262extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
d84f4f99 263 const struct cred *cred,
7e047ef5 264 unsigned long flags,
d720024e 265 struct key *dest);
1da177e4
LT
266
267extern int keyring_clear(struct key *keyring);
268
664cceb0
DH
269extern key_ref_t keyring_search(key_ref_t keyring,
270 struct key_type *type,
271 const char *description);
1da177e4 272
1da177e4
LT
273extern int keyring_add_key(struct key *keyring,
274 struct key *key);
275
276extern struct key *key_lookup(key_serial_t id);
277
456a8167 278static inline key_serial_t key_serial(const struct key *key)
7249db2c
DH
279{
280 return key ? key->serial : 0;
281}
1da177e4 282
59e6b9c1
BS
283extern void key_set_timeout(struct key *, unsigned);
284
78b7280c
DH
285/**
286 * key_is_instantiated - Determine if a key has been positively instantiated
287 * @key: The key to check.
288 *
289 * Return true if the specified key has been positively instantiated, false
290 * otherwise.
291 */
292static inline bool key_is_instantiated(const struct key *key)
293{
294 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
295 !test_bit(KEY_FLAG_NEGATIVE, &key->flags);
296}
297
633e804e
DH
298#define rcu_dereference_key(KEY) \
299 (rcu_dereference_protected((KEY)->payload.rcudata, \
300 rwsem_is_locked(&((struct key *)(KEY))->sem)))
301
ee0b31a2
MZ
302#define rcu_assign_keypointer(KEY, PAYLOAD) \
303 (rcu_assign_pointer((KEY)->payload.rcudata, PAYLOAD))
304
0b77f5bf
DH
305#ifdef CONFIG_SYSCTL
306extern ctl_table key_sysctls[];
307#endif
308
ee18d64c
DH
309extern void key_replace_session_keyring(void);
310
1da177e4
LT
311/*
312 * the userspace interface
313 */
d84f4f99 314extern int install_thread_keyring_to_cred(struct cred *cred);
1da177e4
LT
315extern void key_fsuid_changed(struct task_struct *tsk);
316extern void key_fsgid_changed(struct task_struct *tsk);
317extern void key_init(void);
318
319#else /* CONFIG_KEYS */
320
321#define key_validate(k) 0
322#define key_serial(k) 0
7888e7ff 323#define key_get(k) ({ NULL; })
0dab9cfa 324#define key_revoke(k) do { } while(0)
1da177e4 325#define key_put(k) do { } while(0)
664cceb0 326#define key_ref_put(k) do { } while(0)
8bbf4976
DH
327#define make_key_ref(k, p) NULL
328#define key_ref_to_ptr(k) NULL
664cceb0 329#define is_key_possessed(k) 0
1da177e4
LT
330#define key_fsuid_changed(t) do { } while(0)
331#define key_fsgid_changed(t) do { } while(0)
332#define key_init() do { } while(0)
ee18d64c 333#define key_replace_session_keyring() do { } while(0)
1da177e4
LT
334
335#endif /* CONFIG_KEYS */
336#endif /* __KERNEL__ */
337#endif /* _LINUX_KEY_H */