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>
26 #include <linux/refcount.h>
29 #include <linux/uidgid.h>
31 /* key handle serial number */
32 typedef int32_t key_serial_t
;
34 /* key handle permissions mask */
35 typedef uint32_t key_perm_t
;
43 #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
44 #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
45 #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
46 #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
47 #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
48 #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
49 #define KEY_POS_ALL 0x3f000000
51 #define KEY_USR_VIEW 0x00010000 /* user permissions... */
52 #define KEY_USR_READ 0x00020000
53 #define KEY_USR_WRITE 0x00040000
54 #define KEY_USR_SEARCH 0x00080000
55 #define KEY_USR_LINK 0x00100000
56 #define KEY_USR_SETATTR 0x00200000
57 #define KEY_USR_ALL 0x003f0000
59 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */
60 #define KEY_GRP_READ 0x00000200
61 #define KEY_GRP_WRITE 0x00000400
62 #define KEY_GRP_SEARCH 0x00000800
63 #define KEY_GRP_LINK 0x00001000
64 #define KEY_GRP_SETATTR 0x00002000
65 #define KEY_GRP_ALL 0x00003f00
67 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
68 #define KEY_OTH_READ 0x00000002
69 #define KEY_OTH_WRITE 0x00000004
70 #define KEY_OTH_SEARCH 0x00000008
71 #define KEY_OTH_LINK 0x00000010
72 #define KEY_OTH_SETATTR 0x00000020
73 #define KEY_OTH_ALL 0x0000003f
75 #define KEY_PERM_UNDEF 0xffffffff
87 struct keyring_index_key
{
88 struct key_type
*type
;
89 const char *description
;
94 void __rcu
*rcu_data0
;
98 /*****************************************************************************/
100 * key reference with possession attribute handling
102 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
103 * defined. This is because we abuse the bottom bit of the reference to carry a
104 * flag to indicate whether the calling process possesses that key in one of
107 * the key_ref_t has been made a separate type so that the compiler can reject
108 * attempts to dereference it without proper conversion.
110 * the three functions are used to assemble and disassemble references
112 typedef struct __key_reference_with_attributes
*key_ref_t
;
114 static inline key_ref_t
make_key_ref(const struct key
*key
,
117 return (key_ref_t
) ((unsigned long) key
| possession
);
120 static inline struct key
*key_ref_to_ptr(const key_ref_t key_ref
)
122 return (struct key
*) ((unsigned long) key_ref
& ~1UL);
125 static inline bool is_key_possessed(const key_ref_t key_ref
)
127 return (unsigned long) key_ref
& 1UL;
130 typedef int (*key_restrict_link_func_t
)(struct key
*dest_keyring
,
131 const struct key_type
*type
,
132 const union key_payload
*payload
,
133 struct key
*restriction_key
);
135 struct key_restriction
{
136 key_restrict_link_func_t check
;
138 struct key_type
*keytype
;
141 /*****************************************************************************/
143 * authentication token / access credential / keyring
144 * - types of key include:
146 * - disk encryption IDs
147 * - Kerberos TGTs and tickets
150 refcount_t usage
; /* number of references */
151 key_serial_t serial
; /* key serial number */
153 struct list_head graveyard_link
;
154 struct rb_node serial_node
;
156 struct rw_semaphore sem
; /* change vs change sem */
157 struct key_user
*user
; /* owner of this key */
158 void *security
; /* security data for this key */
160 time_t expiry
; /* time at which key expires (or 0) */
161 time_t revoked_at
; /* time at which key was revoked */
163 time_t last_used_at
; /* last time used for LRU keyring discard */
166 key_perm_t perm
; /* access permissions */
167 unsigned short quotalen
; /* length added to quota */
168 unsigned short datalen
; /* payload data length
169 * - may not match RCU dereferenced payload
170 * - payload should contain own length
175 #define KEY_DEBUG_MAGIC 0x18273645u
176 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
179 unsigned long flags
; /* status flags (change with bitops) */
180 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
181 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
182 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
183 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
184 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
185 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
186 #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */
187 #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */
188 #define KEY_FLAG_BUILTIN 8 /* set if key is built in to the kernel */
189 #define KEY_FLAG_ROOT_CAN_INVAL 9 /* set if key can be invalidated by root without permission */
190 #define KEY_FLAG_KEEP 10 /* set if key should not be removed */
192 /* the key type and key description string
193 * - the desc is used to match a key against search criteria
194 * - it should be a printable string
195 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
198 struct keyring_index_key index_key
;
200 struct key_type
*type
; /* type of key */
206 * - this is used to hold the data actually used in cryptography or
210 union key_payload payload
;
213 struct list_head name_link
;
214 struct assoc_array keys
;
219 /* This is set on a keyring to restrict the addition of a link to a key
220 * to it. If this structure isn't provided then it is assumed that the
221 * keyring is open to any addition. It is ignored for non-keyring
222 * keys. Only set this value using keyring_restrict(), keyring_alloc(),
225 * This is intended for use with rings of trusted keys whereby addition
226 * to the keyring needs to be controlled. KEY_ALLOC_BYPASS_RESTRICTION
227 * overrides this, allowing the kernel to add extra keys without
230 struct key_restriction
*restrict_link
;
233 extern struct key
*key_alloc(struct key_type
*type
,
235 kuid_t uid
, kgid_t gid
,
236 const struct cred
*cred
,
239 struct key_restriction
*restrict_link
);
242 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
243 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
244 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
245 #define KEY_ALLOC_BUILT_IN 0x0004 /* Key is built into kernel */
246 #define KEY_ALLOC_BYPASS_RESTRICTION 0x0008 /* Override the check on restricted keyrings */
248 extern void key_revoke(struct key
*key
);
249 extern void key_invalidate(struct key
*key
);
250 extern void key_put(struct key
*key
);
252 static inline struct key
*__key_get(struct key
*key
)
254 refcount_inc(&key
->usage
);
258 static inline struct key
*key_get(struct key
*key
)
260 return key
? __key_get(key
) : key
;
263 static inline void key_ref_put(key_ref_t key_ref
)
265 key_put(key_ref_to_ptr(key_ref
));
268 extern struct key
*request_key(struct key_type
*type
,
269 const char *description
,
270 const char *callout_info
);
272 extern struct key
*request_key_with_auxdata(struct key_type
*type
,
273 const char *description
,
274 const void *callout_info
,
278 extern struct key
*request_key_async(struct key_type
*type
,
279 const char *description
,
280 const void *callout_info
,
283 extern struct key
*request_key_async_with_auxdata(struct key_type
*type
,
284 const char *description
,
285 const void *callout_info
,
289 extern int wait_for_key_construction(struct key
*key
, bool intr
);
291 extern int key_validate(const struct key
*key
);
293 extern key_ref_t
key_create_or_update(key_ref_t keyring
,
295 const char *description
,
299 unsigned long flags
);
301 extern int key_update(key_ref_t key
,
305 extern int key_link(struct key
*keyring
,
308 extern int key_unlink(struct key
*keyring
,
311 extern struct key
*keyring_alloc(const char *description
, kuid_t uid
, kgid_t gid
,
312 const struct cred
*cred
,
315 struct key_restriction
*restrict_link
,
318 extern int restrict_link_reject(struct key
*keyring
,
319 const struct key_type
*type
,
320 const union key_payload
*payload
,
321 struct key
*restriction_key
);
323 extern int keyring_clear(struct key
*keyring
);
325 extern key_ref_t
keyring_search(key_ref_t keyring
,
326 struct key_type
*type
,
327 const char *description
);
329 extern int keyring_add_key(struct key
*keyring
,
332 extern int keyring_restrict(key_ref_t keyring
, const char *type
,
333 const char *restriction
);
335 extern struct key
*key_lookup(key_serial_t id
);
337 static inline key_serial_t
key_serial(const struct key
*key
)
339 return key
? key
->serial
: 0;
342 extern void key_set_timeout(struct key
*, unsigned);
345 * The permissions required on a key that we're looking up.
347 #define KEY_NEED_VIEW 0x01 /* Require permission to view attributes */
348 #define KEY_NEED_READ 0x02 /* Require permission to read content */
349 #define KEY_NEED_WRITE 0x04 /* Require permission to update / modify */
350 #define KEY_NEED_SEARCH 0x08 /* Require permission to search (keyring) or find (key) */
351 #define KEY_NEED_LINK 0x10 /* Require permission to link */
352 #define KEY_NEED_SETATTR 0x20 /* Require permission to change attributes */
353 #define KEY_NEED_ALL 0x3f /* All the above permissions */
356 * key_is_instantiated - Determine if a key has been positively instantiated
357 * @key: The key to check.
359 * Return true if the specified key has been positively instantiated, false
362 static inline bool key_is_instantiated(const struct key
*key
)
364 return test_bit(KEY_FLAG_INSTANTIATED
, &key
->flags
) &&
365 !test_bit(KEY_FLAG_NEGATIVE
, &key
->flags
);
368 #define dereference_key_rcu(KEY) \
369 (rcu_dereference((KEY)->payload.rcu_data0))
371 #define dereference_key_locked(KEY) \
372 (rcu_dereference_protected((KEY)->payload.rcu_data0, \
373 rwsem_is_locked(&((struct key *)(KEY))->sem)))
375 #define rcu_assign_keypointer(KEY, PAYLOAD) \
377 rcu_assign_pointer((KEY)->payload.rcu_data0, (PAYLOAD)); \
381 extern struct ctl_table key_sysctls
[];
384 * the userspace interface
386 extern int install_thread_keyring_to_cred(struct cred
*cred
);
387 extern void key_fsuid_changed(struct task_struct
*tsk
);
388 extern void key_fsgid_changed(struct task_struct
*tsk
);
389 extern void key_init(void);
391 #else /* CONFIG_KEYS */
393 #define key_validate(k) 0
394 #define key_serial(k) 0
395 #define key_get(k) ({ NULL; })
396 #define key_revoke(k) do { } while(0)
397 #define key_invalidate(k) do { } while(0)
398 #define key_put(k) do { } while(0)
399 #define key_ref_put(k) do { } while(0)
400 #define make_key_ref(k, p) NULL
401 #define key_ref_to_ptr(k) NULL
402 #define is_key_possessed(k) 0
403 #define key_fsuid_changed(t) do { } while(0)
404 #define key_fsgid_changed(t) do { } while(0)
405 #define key_init() do { } while(0)
407 #endif /* CONFIG_KEYS */
408 #endif /* __KERNEL__ */
409 #endif /* _LINUX_KEY_H */