1 /* Authentication token and access key management
3 * Copyright (C) 2004, 2007 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
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.
12 * See Documentation/security/keys.txt for information on keys/keyrings.
18 #include <linux/types.h>
19 #include <linux/list.h>
20 #include <linux/rbtree.h>
21 #include <linux/rcupdate.h>
22 #include <linux/sysctl.h>
23 #include <linux/rwsem.h>
24 #include <linux/atomic.h>
25 #include <linux/assoc_array.h>
28 #include <linux/uidgid.h>
30 /* key handle serial number */
31 typedef int32_t key_serial_t
;
33 /* key handle permissions mask */
34 typedef uint32_t key_perm_t
;
42 #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
43 #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
44 #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
45 #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
46 #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
47 #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
48 #define KEY_POS_ALL 0x3f000000
50 #define KEY_USR_VIEW 0x00010000 /* user permissions... */
51 #define KEY_USR_READ 0x00020000
52 #define KEY_USR_WRITE 0x00040000
53 #define KEY_USR_SEARCH 0x00080000
54 #define KEY_USR_LINK 0x00100000
55 #define KEY_USR_SETATTR 0x00200000
56 #define KEY_USR_ALL 0x003f0000
58 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */
59 #define KEY_GRP_READ 0x00000200
60 #define KEY_GRP_WRITE 0x00000400
61 #define KEY_GRP_SEARCH 0x00000800
62 #define KEY_GRP_LINK 0x00001000
63 #define KEY_GRP_SETATTR 0x00002000
64 #define KEY_GRP_ALL 0x00003f00
66 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
67 #define KEY_OTH_READ 0x00000002
68 #define KEY_OTH_WRITE 0x00000004
69 #define KEY_OTH_SEARCH 0x00000008
70 #define KEY_OTH_LINK 0x00000010
71 #define KEY_OTH_SETATTR 0x00000020
72 #define KEY_OTH_ALL 0x0000003f
74 #define KEY_PERM_UNDEF 0xffffffff
86 struct keyring_index_key
{
87 struct key_type
*type
;
88 const char *description
;
93 void __rcu
*rcu_data0
;
97 /*****************************************************************************/
99 * key reference with possession attribute handling
101 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
102 * defined. This is because we abuse the bottom bit of the reference to carry a
103 * flag to indicate whether the calling process possesses that key in one of
106 * the key_ref_t has been made a separate type so that the compiler can reject
107 * attempts to dereference it without proper conversion.
109 * the three functions are used to assemble and disassemble references
111 typedef struct __key_reference_with_attributes
*key_ref_t
;
113 static inline key_ref_t
make_key_ref(const struct key
*key
,
116 return (key_ref_t
) ((unsigned long) key
| possession
);
119 static inline struct key
*key_ref_to_ptr(const key_ref_t key_ref
)
121 return (struct key
*) ((unsigned long) key_ref
& ~1UL);
124 static inline bool is_key_possessed(const key_ref_t key_ref
)
126 return (unsigned long) key_ref
& 1UL;
129 /*****************************************************************************/
131 * authentication token / access credential / keyring
132 * - types of key include:
134 * - disk encryption IDs
135 * - Kerberos TGTs and tickets
138 atomic_t usage
; /* number of references */
139 key_serial_t serial
; /* key serial number */
141 struct list_head graveyard_link
;
142 struct rb_node serial_node
;
144 struct rw_semaphore sem
; /* change vs change sem */
145 struct key_user
*user
; /* owner of this key */
146 void *security
; /* security data for this key */
148 time_t expiry
; /* time at which key expires (or 0) */
149 time_t revoked_at
; /* time at which key was revoked */
151 time_t last_used_at
; /* last time used for LRU keyring discard */
154 key_perm_t perm
; /* access permissions */
155 unsigned short quotalen
; /* length added to quota */
156 unsigned short datalen
; /* payload data length
157 * - may not match RCU dereferenced payload
158 * - payload should contain own length
163 #define KEY_DEBUG_MAGIC 0x18273645u
164 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
167 unsigned long flags
; /* status flags (change with bitops) */
168 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
169 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
170 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
171 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
172 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
173 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
174 #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */
175 #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */
176 #define KEY_FLAG_TRUSTED 8 /* set if key is trusted */
177 #define KEY_FLAG_TRUSTED_ONLY 9 /* set if keyring only accepts links to trusted keys */
178 #define KEY_FLAG_BUILTIN 10 /* set if key is builtin */
179 #define KEY_FLAG_ROOT_CAN_INVAL 11 /* set if key can be invalidated by root without permission */
180 #define KEY_FLAG_KEEP 12 /* set if key should not be removed */
182 /* the key type and key description string
183 * - the desc is used to match a key against search criteria
184 * - it should be a printable string
185 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
188 struct keyring_index_key index_key
;
190 struct key_type
*type
; /* type of key */
196 * - this is used to hold the data actually used in cryptography or
200 union key_payload payload
;
203 struct list_head name_link
;
204 struct assoc_array keys
;
210 extern struct key
*key_alloc(struct key_type
*type
,
212 kuid_t uid
, kgid_t gid
,
213 const struct cred
*cred
,
215 unsigned long flags
);
218 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
219 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
220 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
221 #define KEY_ALLOC_TRUSTED 0x0004 /* Key should be flagged as trusted */
223 extern void key_revoke(struct key
*key
);
224 extern void key_invalidate(struct key
*key
);
225 extern void key_put(struct key
*key
);
227 static inline struct key
*__key_get(struct key
*key
)
229 atomic_inc(&key
->usage
);
233 static inline struct key
*key_get(struct key
*key
)
235 return key
? __key_get(key
) : key
;
238 static inline void key_ref_put(key_ref_t key_ref
)
240 key_put(key_ref_to_ptr(key_ref
));
243 extern struct key
*request_key(struct key_type
*type
,
244 const char *description
,
245 const char *callout_info
);
247 extern struct key
*request_key_with_auxdata(struct key_type
*type
,
248 const char *description
,
249 const void *callout_info
,
253 extern struct key
*request_key_async(struct key_type
*type
,
254 const char *description
,
255 const void *callout_info
,
258 extern struct key
*request_key_async_with_auxdata(struct key_type
*type
,
259 const char *description
,
260 const void *callout_info
,
264 extern int wait_for_key_construction(struct key
*key
, bool intr
);
266 extern int key_validate(const struct key
*key
);
268 extern key_ref_t
key_create_or_update(key_ref_t keyring
,
270 const char *description
,
274 unsigned long flags
);
276 extern int key_update(key_ref_t key
,
280 extern int key_link(struct key
*keyring
,
283 extern int key_unlink(struct key
*keyring
,
286 extern struct key
*keyring_alloc(const char *description
, kuid_t uid
, kgid_t gid
,
287 const struct cred
*cred
,
292 extern int keyring_clear(struct key
*keyring
);
294 extern key_ref_t
keyring_search(key_ref_t keyring
,
295 struct key_type
*type
,
296 const char *description
);
298 extern int keyring_add_key(struct key
*keyring
,
301 extern struct key
*key_lookup(key_serial_t id
);
303 static inline key_serial_t
key_serial(const struct key
*key
)
305 return key
? key
->serial
: 0;
308 extern void key_set_timeout(struct key
*, unsigned);
311 * The permissions required on a key that we're looking up.
313 #define KEY_NEED_VIEW 0x01 /* Require permission to view attributes */
314 #define KEY_NEED_READ 0x02 /* Require permission to read content */
315 #define KEY_NEED_WRITE 0x04 /* Require permission to update / modify */
316 #define KEY_NEED_SEARCH 0x08 /* Require permission to search (keyring) or find (key) */
317 #define KEY_NEED_LINK 0x10 /* Require permission to link */
318 #define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */
319 #define KEY_NEED_ALL 0x3f /* All the above permissions */
322 * key_is_instantiated - Determine if a key has been positively instantiated
323 * @key: The key to check.
325 * Return true if the specified key has been positively instantiated, false
328 static inline bool key_is_instantiated(const struct key
*key
)
330 return test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
) &&
331 !test_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
334 #define rcu_dereference_key(KEY) \
335 (rcu_dereference_protected((KEY)->payload.rcu_data0, \
336 rwsem_is_locked(&((struct key *)(KEY))->sem)))
338 #define rcu_assign_keypointer(KEY, PAYLOAD) \
340 rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \
344 extern struct ctl_table key_sysctls
[];
347 * the userspace interface
349 extern int install_thread_keyring_to_cred(struct cred
*cred
);
350 extern void key_fsuid_changed(struct task_struct
*tsk
);
351 extern void key_fsgid_changed(struct task_struct
*tsk
);
352 extern void key_init(void);
354 #else /* CONFIG_KEYS */
356 #define key_validate(k) 0
357 #define key_serial(k) 0
358 #define key_get(k) ({ NULL; })
359 #define key_revoke(k) do { } while(0)
360 #define key_invalidate(k) do { } while(0)
361 #define key_put(k) do { } while(0)
362 #define key_ref_put(k) do { } while(0)
363 #define make_key_ref(k, p) NULL
364 #define key_ref_to_ptr(k) NULL
365 #define is_key_possessed(k) 0
366 #define key_fsuid_changed(t) do { } while(0)
367 #define key_fsgid_changed(t) do { } while(0)
368 #define key_init() do { } while(0)
370 #endif /* CONFIG_KEYS */
371 #endif /* __KERNEL__ */
372 #endif /* _LINUX_KEY_H */