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>
28 /* key handle serial number */
29 typedef int32_t key_serial_t;
31 /* key handle permissions mask */
32 typedef uint32_t key_perm_t;
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 */
45 #define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
46 #define KEY_POS_ALL 0x3f000000
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
53 #define KEY_USR_SETATTR 0x00200000
54 #define KEY_USR_ALL 0x003f0000
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
61 #define KEY_GRP_SETATTR 0x00002000
62 #define KEY_GRP_ALL 0x00003f00
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
69 #define KEY_OTH_SETATTR 0x00000020
70 #define KEY_OTH_ALL 0x0000003f
72 #define KEY_PERM_UNDEF 0xffffffff
84 /*****************************************************************************/
86 * key reference with possession attribute handling
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
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.
96 * the three functions are used to assemble and disassemble references
98 typedef struct __key_reference_with_attributes *key_ref_t;
100 static inline key_ref_t make_key_ref(const struct key *key,
101 unsigned long possession)
103 return (key_ref_t) ((unsigned long) key | possession);
106 static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
108 return (struct key *) ((unsigned long) key_ref & ~1UL);
111 static inline unsigned long is_key_possessed(const key_ref_t key_ref)
113 return (unsigned long) key_ref & 1UL;
116 /*****************************************************************************/
118 * authentication token / access credential / keyring
119 * - types of key include:
121 * - disk encryption IDs
122 * - Kerberos TGTs and tickets
125 atomic_t usage; /* number of references */
126 key_serial_t serial; /* key serial number */
127 struct rb_node serial_node;
128 struct key_type *type; /* type of key */
129 struct rw_semaphore sem; /* change vs change sem */
130 struct key_user *user; /* owner of this key */
131 void *security; /* security data for this key */
133 time_t expiry; /* time at which key expires (or 0) */
134 time_t revoked_at; /* time at which key was revoked */
138 key_perm_t perm; /* access permissions */
139 unsigned short quotalen; /* length added to quota */
140 unsigned short datalen; /* payload data length
141 * - may not match RCU dereferenced payload
142 * - payload should contain own length
147 #define KEY_DEBUG_MAGIC 0x18273645u
148 #define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
151 unsigned long flags; /* status flags (change with bitops) */
152 #define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
153 #define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
154 #define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
155 #define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
156 #define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
157 #define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
158 #define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */
160 /* the description string
161 * - this is used to match a key against search criteria
162 * - this should be a printable string
163 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
167 /* type specific data
168 * - this is used by the keyring type to index the name
171 struct list_head link;
178 * - this is used to hold the data actually used in cryptography or
185 struct keyring_list __rcu *subscriptions;
189 extern struct key *key_alloc(struct key_type *type,
191 uid_t uid, gid_t gid,
192 const struct cred *cred,
194 unsigned long flags);
197 #define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
198 #define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
199 #define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
201 extern void key_revoke(struct key *key);
202 extern void key_put(struct key *key);
204 static inline struct key *key_get(struct key *key)
207 atomic_inc(&key->usage);
211 static inline void key_ref_put(key_ref_t key_ref)
213 key_put(key_ref_to_ptr(key_ref));
216 extern struct key *request_key(struct key_type *type,
217 const char *description,
218 const char *callout_info);
220 extern struct key *request_key_with_auxdata(struct key_type *type,
221 const char *description,
222 const void *callout_info,
226 extern struct key *request_key_async(struct key_type *type,
227 const char *description,
228 const void *callout_info,
231 extern struct key *request_key_async_with_auxdata(struct key_type *type,
232 const char *description,
233 const void *callout_info,
237 extern int wait_for_key_construction(struct key *key, bool intr);
239 extern int key_validate(struct key *key);
241 extern key_ref_t key_create_or_update(key_ref_t keyring,
243 const char *description,
247 unsigned long flags);
249 extern int key_update(key_ref_t key,
253 extern int key_link(struct key *keyring,
256 extern int key_unlink(struct key *keyring,
259 extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
260 const struct cred *cred,
264 extern int keyring_clear(struct key *keyring);
266 extern key_ref_t keyring_search(key_ref_t keyring,
267 struct key_type *type,
268 const char *description);
270 extern int keyring_add_key(struct key *keyring,
273 extern struct key *key_lookup(key_serial_t id);
275 static inline key_serial_t key_serial(const struct key *key)
277 return key ? key->serial : 0;
281 * key_is_instantiated - Determine if a key has been positively instantiated
282 * @key: The key to check.
284 * Return true if the specified key has been positively instantiated, false
287 static inline bool key_is_instantiated(const struct key *key)
289 return test_bit(KEY_FLAG_INSTANTIATED, &key->flags) &&
290 !test_bit(KEY_FLAG_NEGATIVE, &key->flags);
293 #define rcu_dereference_key(KEY) \
294 (rcu_dereference_protected((KEY)->payload.rcudata, \
295 rwsem_is_locked(&((struct key *)(KEY))->sem)))
297 #define rcu_assign_keypointer(KEY, PAYLOAD) \
298 (rcu_assign_pointer((KEY)->payload.rcudata, PAYLOAD))
301 extern ctl_table key_sysctls[];
304 extern void key_replace_session_keyring(void);
307 * the userspace interface
309 extern int install_thread_keyring_to_cred(struct cred *cred);
310 extern void key_fsuid_changed(struct task_struct *tsk);
311 extern void key_fsgid_changed(struct task_struct *tsk);
312 extern void key_init(void);
314 #else /* CONFIG_KEYS */
316 #define key_validate(k) 0
317 #define key_serial(k) 0
318 #define key_get(k) ({ NULL; })
319 #define key_revoke(k) do { } while(0)
320 #define key_put(k) do { } while(0)
321 #define key_ref_put(k) do { } while(0)
322 #define make_key_ref(k, p) NULL
323 #define key_ref_to_ptr(k) NULL
324 #define is_key_possessed(k) 0
325 #define key_fsuid_changed(t) do { } while(0)
326 #define key_fsgid_changed(t) do { } while(0)
327 #define key_init() do { } while(0)
328 #define key_replace_session_keyring() do { } while(0)
330 #endif /* CONFIG_KEYS */
331 #endif /* __KERNEL__ */
332 #endif /* _LINUX_KEY_H */