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>
27 #include <linux/uidgid.h>
29 /* key handle serial number */
30 typedef int32_t key_serial_t;
32 /* key handle permissions mask */
33 typedef uint32_t key_perm_t;
41 #define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
42 #define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
43 #define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
44 #define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
45 #define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
46 #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
47 #define KEY_POS_ALL 0x3f000000
49 #define KEY_USR_VIEW 0x00010000 /* user permissions... */
50 #define KEY_USR_READ 0x00020000
51 #define KEY_USR_WRITE 0x00040000
52 #define KEY_USR_SEARCH 0x00080000
53 #define KEY_USR_LINK 0x00100000
54 #define KEY_USR_SETATTR 0x00200000
55 #define KEY_USR_ALL 0x003f0000
57 #define KEY_GRP_VIEW 0x00000100 /* group permissions... */
58 #define KEY_GRP_READ 0x00000200
59 #define KEY_GRP_WRITE 0x00000400
60 #define KEY_GRP_SEARCH 0x00000800
61 #define KEY_GRP_LINK 0x00001000
62 #define KEY_GRP_SETATTR 0x00002000
63 #define KEY_GRP_ALL 0x00003f00
65 #define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
66 #define KEY_OTH_READ 0x00000002
67 #define KEY_OTH_WRITE 0x00000004
68 #define KEY_OTH_SEARCH 0x00000008
69 #define KEY_OTH_LINK 0x00000010
70 #define KEY_OTH_SETATTR 0x00000020
71 #define KEY_OTH_ALL 0x0000003f
73 #define KEY_PERM_UNDEF 0xffffffff
85 struct keyring_index_key {
86 struct key_type *type;
87 const char *description;
91 /*****************************************************************************/
93 * key reference with possession attribute handling
95 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
96 * defined. This is because we abuse the bottom bit of the reference to carry a
97 * flag to indicate whether the calling process possesses that key in one of
100 * the key_ref_t has been made a separate type so that the compiler can reject
101 * attempts to dereference it without proper conversion.
103 * the three functions are used to assemble and disassemble references
105 typedef struct __key_reference_with_attributes *key_ref_t;
107 static inline key_ref_t make_key_ref(const struct key *key,
110 return (key_ref_t) ((unsigned long) key | possession);
113 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
115 return (struct key *) ((unsigned long) key_ref & ~1UL);
118 static inline bool is_key_possessed(const key_ref_t key_ref)
120 return (unsigned long) key_ref & 1UL;
123 /*****************************************************************************/
125 * authentication token / access credential / keyring
126 * - types of key include:
128 * - disk encryption IDs
129 * - Kerberos TGTs and tickets
132 atomic_t usage; /* number of references */
133 key_serial_t serial; /* key serial number */
135 struct list_head graveyard_link;
136 struct rb_node serial_node;
138 struct rw_semaphore sem; /* change vs change sem */
139 struct key_user *user; /* owner of this key */
140 void *security; /* security data for this key */
142 time_t expiry; /* time at which key expires (or 0) */
143 time_t revoked_at; /* time at which key was revoked */
145 time_t last_used_at; /* last time used for LRU keyring discard */
148 key_perm_t perm; /* access permissions */
149 unsigned short quotalen; /* length added to quota */
150 unsigned short datalen; /* payload data length
151 * - may not match RCU dereferenced payload
152 * - payload should contain own length
157 #define KEY_DEBUG_MAGIC 0x18273645u
158 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
161 unsigned long flags; /* status flags (change with bitops) */
162 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
163 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
164 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
165 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
166 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
167 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
168 #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */
169 #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */
171 /* the key type and key description string
172 * - the desc is used to match a key against search criteria
173 * - it should be a printable string
174 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
177 struct keyring_index_key index_key;
179 struct key_type *type; /* type of key */
184 /* type specific data
185 * - this is used by the keyring type to index the name
188 struct list_head link;
195 * - this is used to hold the data actually used in cryptography or
202 struct keyring_list __rcu *subscriptions;
206 extern struct key *key_alloc(struct key_type *type,
208 kuid_t uid, kgid_t gid,
209 const struct cred *cred,
211 unsigned long flags);
214 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
215 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
216 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
218 extern void key_revoke(struct key *key);
219 extern void key_invalidate(struct key *key);
220 extern void key_put(struct key *key);
222 static inline struct key *__key_get(struct key *key)
224 atomic_inc(&key->usage);
228 static inline struct key *key_get(struct key *key)
230 return key ? __key_get(key) : key;
233 static inline void key_ref_put(key_ref_t key_ref)
235 key_put(key_ref_to_ptr(key_ref));
238 extern struct key *request_key(struct key_type *type,
239 const char *description,
240 const char *callout_info);
242 extern struct key *request_key_with_auxdata(struct key_type *type,
243 const char *description,
244 const void *callout_info,
248 extern struct key *request_key_async(struct key_type *type,
249 const char *description,
250 const void *callout_info,
253 extern struct key *request_key_async_with_auxdata(struct key_type *type,
254 const char *description,
255 const void *callout_info,
259 extern int wait_for_key_construction(struct key *key, bool intr);
261 extern int key_validate(const struct key *key);
263 extern key_ref_t key_create_or_update(key_ref_t keyring,
265 const char *description,
269 unsigned long flags);
271 extern int key_update(key_ref_t key,
275 extern int key_link(struct key *keyring,
278 extern int key_unlink(struct key *keyring,
281 extern struct key *keyring_alloc(const char *description, kuid_t uid, kgid_t gid,
282 const struct cred *cred,
287 extern int keyring_clear(struct key *keyring);
289 extern key_ref_t keyring_search(key_ref_t keyring,
290 struct key_type *type,
291 const char *description);
293 extern int keyring_add_key(struct key *keyring,
296 extern struct key *key_lookup(key_serial_t id);
298 static inline key_serial_t key_serial(const struct key *key)
300 return key ? key->serial : 0;
303 extern void key_set_timeout(struct key *, unsigned);
306 * key_is_instantiated - Determine if a key has been positively instantiated
307 * @key: The key to check.
309 * Return true if the specified key has been positively instantiated, false
312 static inline bool key_is_instantiated(const struct key *key)
314 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
315 !test_bit(KEY_FLAG_NEGATIVE, &key->flags);
318 #define rcu_dereference_key(KEY) \
319 (rcu_dereference_protected((KEY)->payload.rcudata, \
320 rwsem_is_locked(&((struct key *)(KEY))->sem)))
322 #define rcu_assign_keypointer(KEY, PAYLOAD) \
324 rcu_assign_pointer((KEY)->payload.rcudata, (PAYLOAD)); \
328 extern ctl_table key_sysctls[];
331 * the userspace interface
333 extern int install_thread_keyring_to_cred(struct cred *cred);
334 extern void key_fsuid_changed(struct task_struct *tsk);
335 extern void key_fsgid_changed(struct task_struct *tsk);
336 extern void key_init(void);
338 #else /* CONFIG_KEYS */
340 #define key_validate(k) 0
341 #define key_serial(k) 0
342 #define key_get(k) ({ NULL; })
343 #define key_revoke(k) do { } while(0)
344 #define key_invalidate(k) do { } while(0)
345 #define key_put(k) do { } while(0)
346 #define key_ref_put(k) do { } while(0)
347 #define make_key_ref(k, p) NULL
348 #define key_ref_to_ptr(k) NULL
349 #define is_key_possessed(k) 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)
354 #endif /* CONFIG_KEYS */
355 #endif /* __KERNEL__ */
356 #endif /* _LINUX_KEY_H */