Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/shaggy...
[deliverable/linux.git] / include / linux / key.h
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1/* key.h: authentication token and access key management
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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 *
12 * See Documentation/keys.txt for information on keys/keyrings.
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>
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22#include <asm/atomic.h>
23
24#ifdef __KERNEL__
25
26/* key handle serial number */
27typedef int32_t key_serial_t;
28
29/* key handle permissions mask */
30typedef uint32_t key_perm_t;
31
32struct key;
33
34#ifdef CONFIG_KEYS
35
36#undef KEY_DEBUGGING
37
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38#define KEY_POS_VIEW 0x01000000 /* possessor can view a key's attributes */
39#define KEY_POS_READ 0x02000000 /* possessor can read key payload / view keyring */
40#define KEY_POS_WRITE 0x04000000 /* possessor can update key payload / add link to keyring */
41#define KEY_POS_SEARCH 0x08000000 /* possessor can find a key in search / search a keyring */
42#define KEY_POS_LINK 0x10000000 /* possessor can create a link to a key/keyring */
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43#define KEY_POS_SETATTR 0x20000000 /* possessor can set key attributes */
44#define KEY_POS_ALL 0x3f000000
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45
46#define KEY_USR_VIEW 0x00010000 /* user permissions... */
47#define KEY_USR_READ 0x00020000
48#define KEY_USR_WRITE 0x00040000
49#define KEY_USR_SEARCH 0x00080000
50#define KEY_USR_LINK 0x00100000
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51#define KEY_USR_SETATTR 0x00200000
52#define KEY_USR_ALL 0x003f0000
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53
54#define KEY_GRP_VIEW 0x00000100 /* group permissions... */
55#define KEY_GRP_READ 0x00000200
56#define KEY_GRP_WRITE 0x00000400
57#define KEY_GRP_SEARCH 0x00000800
58#define KEY_GRP_LINK 0x00001000
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59#define KEY_GRP_SETATTR 0x00002000
60#define KEY_GRP_ALL 0x00003f00
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61
62#define KEY_OTH_VIEW 0x00000001 /* third party permissions... */
63#define KEY_OTH_READ 0x00000002
64#define KEY_OTH_WRITE 0x00000004
65#define KEY_OTH_SEARCH 0x00000008
66#define KEY_OTH_LINK 0x00000010
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67#define KEY_OTH_SETATTR 0x00000020
68#define KEY_OTH_ALL 0x0000003f
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69
70struct seq_file;
71struct user_struct;
72struct signal_struct;
73
74struct key_type;
75struct key_owner;
76struct keyring_list;
77struct keyring_name;
78
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79/*****************************************************************************/
80/*
81 * key reference with possession attribute handling
82 *
83 * NOTE! key_ref_t is a typedef'd pointer to a type that is not actually
84 * defined. This is because we abuse the bottom bit of the reference to carry a
85 * flag to indicate whether the calling process possesses that key in one of
86 * its keyrings.
87 *
88 * the key_ref_t has been made a separate type so that the compiler can reject
89 * attempts to dereference it without proper conversion.
90 *
91 * the three functions are used to assemble and disassemble references
92 */
93typedef struct __key_reference_with_attributes *key_ref_t;
94
95static inline key_ref_t make_key_ref(const struct key *key,
96 unsigned long possession)
97{
98 return (key_ref_t) ((unsigned long) key | possession);
99}
100
101static inline struct key *key_ref_to_ptr(const key_ref_t key_ref)
102{
103 return (struct key *) ((unsigned long) key_ref & ~1UL);
104}
105
106static inline unsigned long is_key_possessed(const key_ref_t key_ref)
107{
108 return (unsigned long) key_ref & 1UL;
109}
110
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111/*****************************************************************************/
112/*
113 * authentication token / access credential / keyring
114 * - types of key include:
115 * - keyrings
116 * - disk encryption IDs
117 * - Kerberos TGTs and tickets
118 */
119struct key {
120 atomic_t usage; /* number of references */
121 key_serial_t serial; /* key serial number */
122 struct rb_node serial_node;
123 struct key_type *type; /* type of key */
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124 struct rw_semaphore sem; /* change vs change sem */
125 struct key_user *user; /* owner of this key */
29db9190 126 void *security; /* security data for this key */
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127 time_t expiry; /* time at which key expires (or 0) */
128 uid_t uid;
129 gid_t gid;
130 key_perm_t perm; /* access permissions */
131 unsigned short quotalen; /* length added to quota */
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132 unsigned short datalen; /* payload data length
133 * - may not match RCU dereferenced payload
134 * - payload should contain own length
135 */
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136
137#ifdef KEY_DEBUGGING
138 unsigned magic;
139#define KEY_DEBUG_MAGIC 0x18273645u
140#define KEY_DEBUG_MAGIC_X 0xf8e9dacbu
141#endif
142
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143 unsigned long flags; /* status flags (change with bitops) */
144#define KEY_FLAG_INSTANTIATED 0 /* set if key has been instantiated */
145#define KEY_FLAG_DEAD 1 /* set if key type has been deleted */
146#define KEY_FLAG_REVOKED 2 /* set if key had been revoked */
147#define KEY_FLAG_IN_QUOTA 3 /* set if key consumes quota */
148#define KEY_FLAG_USER_CONSTRUCT 4 /* set if key is being constructed in userspace */
149#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
150
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151 /* the description string
152 * - this is used to match a key against search criteria
153 * - this should be a printable string
154 * - eg: for krb5 AFS, this might be "afs@REDHAT.COM"
155 */
156 char *description;
157
158 /* type specific data
159 * - this is used by the keyring type to index the name
160 */
161 union {
162 struct list_head link;
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163 unsigned long x[2];
164 void *p[2];
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165 } type_data;
166
167 /* key data
168 * - this is used to hold the data actually used in cryptography or
169 * whatever
170 */
171 union {
172 unsigned long value;
173 void *data;
174 struct keyring_list *subscriptions;
175 } payload;
176};
177
178/*****************************************************************************/
179/*
180 * kernel managed key type definition
181 */
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182typedef int (*request_key_actor_t)(struct key *key, struct key *authkey,
183 const char *op, void *aux);
b5f545c8 184
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185struct key_type {
186 /* name of the type */
187 const char *name;
188
189 /* default payload length for quota precalculation (optional)
190 * - this can be used instead of calling key_payload_reserve(), that
191 * function only needs to be called if the real datalen is different
192 */
193 size_t def_datalen;
194
195 /* instantiate a key of this type
196 * - this method should call key_payload_reserve() to determine if the
197 * user's quota will hold the payload
198 */
199 int (*instantiate)(struct key *key, const void *data, size_t datalen);
200
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201 /* update a key of this type (optional)
202 * - this method should call key_payload_reserve() to recalculate the
203 * quota consumption
204 * - the key must be locked against read when modifying
205 */
206 int (*update)(struct key *key, const void *data, size_t datalen);
207
208 /* match a key against a description */
209 int (*match)(const struct key *key, const void *desc);
210
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211 /* clear some of the data from a key on revokation (optional)
212 * - the key's semaphore will be write-locked by the caller
213 */
214 void (*revoke)(struct key *key);
215
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216 /* clear the data from a key (optional) */
217 void (*destroy)(struct key *key);
218
219 /* describe a key */
220 void (*describe)(const struct key *key, struct seq_file *p);
221
222 /* read a key's data (optional)
223 * - permission checks will be done by the caller
224 * - the key's semaphore will be readlocked by the caller
225 * - should return the amount of data that could be read, no matter how
226 * much is copied into the buffer
227 * - shouldn't do the copy if the buffer is NULL
228 */
229 long (*read)(const struct key *key, char __user *buffer, size_t buflen);
230
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231 /* handle request_key() for this type instead of invoking
232 * /sbin/request-key (optional)
233 * - key is the key to instantiate
234 * - authkey is the authority to assume when instantiating this key
235 * - op is the operation to be done, usually "create"
236 * - the call must not return until the instantiation process has run
237 * its course
238 */
239 request_key_actor_t request_key;
240
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241 /* internal fields */
242 struct list_head link; /* link in types list */
243};
244
245extern struct key_type key_type_keyring;
246
247extern int register_key_type(struct key_type *ktype);
248extern void unregister_key_type(struct key_type *ktype);
249
250extern struct key *key_alloc(struct key_type *type,
251 const char *desc,
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252 uid_t uid, gid_t gid,
253 struct task_struct *ctx,
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254 key_perm_t perm,
255 unsigned long flags);
256
257
258#define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
259#define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
260#define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
261
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262extern int key_payload_reserve(struct key *key, size_t datalen);
263extern int key_instantiate_and_link(struct key *key,
264 const void *data,
265 size_t datalen,
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266 struct key *keyring,
267 struct key *instkey);
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268extern int key_negate_and_link(struct key *key,
269 unsigned timeout,
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270 struct key *keyring,
271 struct key *instkey);
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272extern void key_revoke(struct key *key);
273extern void key_put(struct key *key);
274
275static inline struct key *key_get(struct key *key)
276{
277 if (key)
278 atomic_inc(&key->usage);
279 return key;
280}
281
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282static inline void key_ref_put(key_ref_t key_ref)
283{
284 key_put(key_ref_to_ptr(key_ref));
285}
286
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287extern struct key *request_key(struct key_type *type,
288 const char *description,
289 const char *callout_info);
290
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291extern struct key *request_key_with_auxdata(struct key_type *type,
292 const char *description,
293 const char *callout_info,
294 void *aux);
295
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296extern int key_validate(struct key *key);
297
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298extern key_ref_t key_create_or_update(key_ref_t keyring,
299 const char *type,
300 const char *description,
301 const void *payload,
302 size_t plen,
7e047ef5 303 unsigned long flags);
1da177e4 304
664cceb0 305extern int key_update(key_ref_t key,
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306 const void *payload,
307 size_t plen);
308
309extern int key_link(struct key *keyring,
310 struct key *key);
311
312extern int key_unlink(struct key *keyring,
313 struct key *key);
314
315extern struct key *keyring_alloc(const char *description, uid_t uid, gid_t gid,
d720024e 316 struct task_struct *ctx,
7e047ef5 317 unsigned long flags,
d720024e 318 struct key *dest);
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319
320extern int keyring_clear(struct key *keyring);
321
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322extern key_ref_t keyring_search(key_ref_t keyring,
323 struct key_type *type,
324 const char *description);
1da177e4 325
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326extern int keyring_add_key(struct key *keyring,
327 struct key *key);
328
329extern struct key *key_lookup(key_serial_t id);
330
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331extern void keyring_replace_payload(struct key *key, void *replacement);
332
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333#define key_serial(key) ((key) ? (key)->serial : 0)
334
335/*
336 * the userspace interface
337 */
338extern struct key root_user_keyring, root_session_keyring;
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339extern int alloc_uid_keyring(struct user_struct *user,
340 struct task_struct *ctx);
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341extern void switch_uid_keyring(struct user_struct *new_user);
342extern int copy_keys(unsigned long clone_flags, struct task_struct *tsk);
343extern int copy_thread_group_keys(struct task_struct *tsk);
344extern void exit_keys(struct task_struct *tsk);
345extern void exit_thread_group_keys(struct signal_struct *tg);
346extern int suid_keys(struct task_struct *tsk);
347extern int exec_keys(struct task_struct *tsk);
348extern void key_fsuid_changed(struct task_struct *tsk);
349extern void key_fsgid_changed(struct task_struct *tsk);
350extern void key_init(void);
351
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DH
352#define __install_session_keyring(tsk, keyring) \
353({ \
354 struct key *old_session = tsk->signal->session_keyring; \
355 tsk->signal->session_keyring = keyring; \
356 old_session; \
357})
358
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359#else /* CONFIG_KEYS */
360
361#define key_validate(k) 0
362#define key_serial(k) 0
7888e7ff 363#define key_get(k) ({ NULL; })
1da177e4 364#define key_put(k) do { } while(0)
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DH
365#define key_ref_put(k) do { } while(0)
366#define make_key_ref(k) ({ NULL; })
367#define key_ref_to_ptr(k) ({ NULL; })
368#define is_key_possessed(k) 0
d720024e 369#define alloc_uid_keyring(u,c) 0
1da177e4 370#define switch_uid_keyring(u) do { } while(0)
7888e7ff 371#define __install_session_keyring(t, k) ({ NULL; })
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372#define copy_keys(f,t) 0
373#define copy_thread_group_keys(t) 0
374#define exit_keys(t) do { } while(0)
375#define exit_thread_group_keys(tg) do { } while(0)
376#define suid_keys(t) do { } while(0)
377#define exec_keys(t) do { } while(0)
378#define key_fsuid_changed(t) do { } while(0)
379#define key_fsgid_changed(t) do { } while(0)
380#define key_init() do { } while(0)
381
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382/* Initial keyrings */
383extern struct key root_user_keyring;
384extern struct key root_session_keyring;
385
1da177e4
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386#endif /* CONFIG_KEYS */
387#endif /* __KERNEL__ */
388#endif /* _LINUX_KEY_H */
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